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KING'S 
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LONDON 

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KING'S  COLLEGE  LONDON 


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THE 

CYCLOPAEDIA 

OF 

ANATOMY  and  PHYSIOLOGY. 


VOL.  II. 


LONDON : 

MARCHANT,  PRINTER,  I NG RAM-COURT- 


THE 


OF 

ANATOMY  and  PHYSIOLOGY. 

EDITED  BY 

ROBERT  B.  TODD,  M.D.  F.R.S. 

FELLOW    OF    THE    ROYAL    COLLEGE    OF  PHYSICIANS) 
PROFESSOR   OF  PHYSIOLOGY    AND  OF   GENERAL   AND  MORBID  ANATOMY   IN  KING'S  COLLEGE, 

LONDON,   ETC.  ETC. 


I)  I  A  I  N  8. 


LONDON: 

SHERWOOD,   GILBERT,  AND  PIPER, 

PATERNOSTER- ROW. 

1839. 


CONTRIBUTORS. 


ROBERT  ADAMS,  Esq. 

Surgeon  to  the  Richmond  Hospital,  and  Lecturer  on 
Anatomy  and  Surgery,  Duhlin. 

B.  ALCOCK,  M.B.  Dublin. 
W.  P.  ALISON,  M.D.  F.R.S.E. 

Professor  of  the  Institutes  of  Medicine  in  the  Univer- 
sity of  Edinburgh,  &c. 

JOHN  ANDERSON,  Esq.  M.E.S. Richmond. 
J.  APJOHN,  M.D.  M.R.I.A. 

Prof,  of  Chem.  to  the  Royal  Coll.'of  Surgeons,  Ireland. 

VICTOR  AUDOUIN,  M.D.  Paris. 

Profcsseur-Administrateurau  Musecd'Histoire  Naturelle. 

B.  G.  BABINGTON,  M.D.  F.R.S. 
THOMAS  BELL,  F.R.S. 

Professor  of  Zoology  in  King's  College,  London. 

CHARLES  BENSON,  M.D.  M.R.I.A. 

Prof,  of  Med.  to  the  Royal  Col.  of  Surgeons,  Ireland. 

JOHN  BOSTOCK,  M.D.  V.P.R.S.  London. 
W.  BOWMAN,  Esq. 

Demonstrator  of  Anatomy,  King's  College,  London. 

W.  T.  BRANDE,  F.R.S. 

Professor  of  Chemistry  to  the  Royal  Institution,  &c. 

J.  E.  BRENAN,  M.D. 
G.BRESCHET,  M.D. 

Surgeon  to  the  Hotel-Dieu,  Paris. 

W.  B.  CARPENTER,  Esq. 

Lect.  on  Forensic  Med.  at  the  Bristol  Med.  Sch.,  &c. 

JOHN  COLDSTREAM,  M.D.  Leith. 

Member  of  the  Wernerian  Natural  History  Society  of 
Edinburgh,  &c.  &c. 

DAVID  CRAIGIE,  M.D.  F.R.S.E. 

Fellow  of  the  RoyalCollege  of  Physicians,Edinburgh,&c. 

T.  BLIZARD  CURLING,  Esq. 

Assistant  Surgeon  to  the  London  Hospital,  and  Lec- 
turer on  Morbid  Anatomv. 

G.  P.  DESHAYES,  M.D.  Paris. 
A.  T.  S.  DODD,  Esq. 

Surgeon  to  the  Infirmary,  Chichester,  and  late  Demon- 
strator of  Anatomy  at  Guy's  Hospital. 

H.  DUTROCHET,  M.D. 

Member  of  the  Institute  of  France,  Paris. 

W.F.EDWARDS,  M.D.  F.R.S. 

Member  of  the  Institute  of  France,  Paris. 

H.  MILNE  EDWARDS,  M.D. 

Professor  of  Natural  History  to  the  College  of  Henry 
IV.,  and  to  the  Central  School  of  Arts  and  Manu- 
factures, Paris. 

ARTHUR  FARRE,  M.B.  F.R.S. 

Physician  to  the  Gen.  Disp.,  and  Lect.  on  Forensic 
Med.  and  Comp.  Anat.  and  Physiol,  at  St.  Bartholo- 
mew's Hospital. 

R.  D.  GRAINGER,  Esq. 

Lecturer  on  Anatomy  and  Physiology  at  the  Webb- 
Street  School  of  Anatomy. 

R.  E.  GRANT,  M.D.  F.R.S.  L.  &  E. 

Fellow  of  the  Royal  College  of  Physicians,  Edinburgh, 
and  Professor  of  Comparative  Anatomy  and  Zoology  in 
University  College,  &c.  &c. 

MARSHALL  HALL,  M.D.  F.R.S.  L.  &  E. 

London. 
HENRY  HANCOCK,  Esq. 

Lect.  on  Anat.  and  Physiology  at,  and  Surgeon  to  the 
Charing-Crnss  Hospital. 

ROBERT  HARRISON,  M.D.  M.R.I.A. 

Prof,  of  Anat.  and  Surg,  in  the  Univ.  of  Dublin. 

JOHN  HART,  M.D.  M.RJ.A. 

Prof,  of  Anat.  in  the  Royal  Coll.  of  Sur.  Dublin. 

ISID.  GEOFFROY  ST.  H1LAIRE,  M.D. 

Member  of  the  Institute  of  France,  Paris. 

ARTHUR  JACOB,  M.D.  M.R.I.A. 

Professor  of  Anatomy  and  Physiology  to  the  Royal 
College  of  Surgeons  in  Ireland. 

T.  RYMER  JONES,  Esq. 

Prof,  of  Comp.  Anat.,  in  King's  College,  London. 


T.  WHARTON  JONES,  Esq.  London. 
F.  KIERNAN,  F.R.S.  London. 
T.  WILKINSON  KING,  Esq. 

Lect.  on  Comp.  Anat.  and  Physiol,  at  Guy's  Hospital. 

SAMUEL  LANE,  Esq. 

Lecturer  on  Anatomy,  St.  George's  Hospital,  London. 

F.  T.  MACDOUGALL,  Esq. 
JOHN  MALYN,  Esq. 

Surgeon  to  the  Western  Dispensary. 

W.  F.  MONTGOMERY,  M.D.  M.R.I.A. 

Fellow  and  Professor  of  Midwifery  to  the  King  and 
Queen's  College  of  Physicians  in  Ireland. 

GEORGE  NEWPORT,  Esq. 

Vice-Pres.  of  the  Entomological  Society  of  London. 

R.  OWEN,  F.R.S.  F.G.S. 

Professor  of  Comparative  Anatomy  and  Physiology  to 
the  Royal  College  of  Surgeons  in  London. 

RICHARD  PARTRIDGE,  F.R.S. 

Prof,  of  Descriptive  and  Surgical  Anat.  in  King's  Coll. 
London. 

BENJAMIN  PHILLIPS,  F.R.S.  London. 

Surgeon  to  the  Marylebone  Infirmary. 

W.  H.  PORTER,  Esq. 

Prof,  of  Surgery  to  the  Royal  Coll.  of  Surg,  in  Ireland. 

J.  C.  PRICHARD,  M.D.  F.R.S. 

Corresponding  Member  of  the  Institute  of  France, 
Member  of  the  Royal  Academy  of  Medicine  of  Palis, 
and  Senior  Physician  to  the  Bristol  Infirmary. 

G.  O.  REES,  M.D.  London. 
J.  REID,  M.D.  Edinburgh. 

Fellow  of  the  Royal  College  of  Physicians  in  Edin- 
burgh, and  Lecturer  on  the  Institutes  of  Medicine. 

EDWARD  R1GBY,  M.D.  F.L.S. 

Lect.  on  Midwifery  at  St.  Bartholomew's  Hospital. 

J.  FORBES  ROYLE,  M.D.  V.P.R.S.  F.G.S. 

Professor  of  Materia  Medicain  King's  College,  London. 

HENRY  SEARLE,  Esq.  London. 
E.  R.  A.  SERRES,  M.D. 

Physician  to  the  Hospital  of  La  Pitie,  &c.  &.C.  Paris. 

W.  SHARPEY,  M.D.  F.R.S.E. 

Prof,  of  Anat.  and  Physiol,  in  Univ.  Col.  London. 

JOHN  SIMON,  Esq. 

Demonstrator  of  Anatomy  in  King's  College,  London. 

J.  Y.  SIMPSON,  M.D. 

Fellow  of  the  Royal  College  of  Physicians,  Edinburgh, 
and  Lecturer  on  Midwifery. 

SAMUEL  SOLLY,  F.R.S. 
GABRIEL  STOKES,  M.D. 

Surgeon  to  the  South  Eastern  Dispensary,  and  Demon- 
strator of  Anatomy  in  the  Park-street  School  of  Medi- 
cine, Dublin. 

J.  A.  SYMONDS,  M.D. 

Physician  to  the  Bristol  General  Hospital  and  Dispen- 
sary, and  Lecturer  on  the  Theory  and  Practice  of  Medi- 
cine at  the  Bristol  Medical  School. 

ALLEN  THOMSON,  M.D. 

Fellow  of  the  Royal  College  of  Surgeons,  andLccturer 
on  the  Institutions  of  Medicine,  Edinburgh. 

RUDOLPH  WAGNER,  M.D. 

Professor  of  Medicine  and  of  Comparative  Anatomy 
in  the  Royal  University,  Eiiangen. 

C.  WIIEATSTONE,  F.R.S. 

Professor  of  Natural  Philosophy  in  King's  College, London. 

REV.  G.WILLIS,  F.R.S.  F.G.S.  Cambridge. 
R.  WILLIS,  M.D. 

Physician  to  the  Royal  Infirmary  for  Children,  and 
Lecturer  on  the  Theory  and  Practice  of  Medicine  in 
the  Aldersgate-street  School. 

W.  J.ERASMUS  WILSON,  Esq. 

Leclureron  Anat  .and  Physiol,  in  Sydenham  Coll  Lon.; 
and  Consulting  Surgeon  to  the  St.  Pancras  Infirmary. 

W.  YARRELL,  F.L.S.  F.Z.S. 


CONTENTS  OF  THE  SECOND  VOLUME. 


Diaphragm   Dr.  Benson 

Digestion    Dr.  linstock 

Digestive  Canal   Dr.  Grant 

Echinodermata   Dr.  Sharpey 

Edentata    T.  Bell,  Esq 

Elasticity    Dr.Brcnan 

Elbow,  Region  of  the  Dr.  Hart  . . 
Elbow,    Joint    of,  } 


Page 
1 
6 
27 
.  30 
4G 
55 
62 


Normal  Anatomy 


Dr.  Hart  »   05 


Elbow,  Joint  of,  Ab-  \ 


j  R.  Adams,  Esq.  . .  07 


normal  Anatomy  . 

Electricity,  Animal  ..  Dr.  Coldstream  . . 

Endosmosis    Dr.  Dutrochet  .... 

Entozoa   R.  Owen,  Esq  

Erectile  Tissue  ......  Dr.  Hart  

Excretion    Dr.  Alison  

Extremity   Dr.  Todd  

Eye   Dr.  Jacob  

Face    R.  Partridge,  Esq. 

Fascia   Dr.  Todd  

Fat    W.T.  Brande,Esq. 

Femoral  Artery   Dr.  Alcock  

Fibrine    W.T.  Brande,  Esq. 

Fibro-Cartilage   Dr.  Todd  

Fibrous  Tissue   R.D.Grainger, Esq. 

Fibular  Artery   Dr.  Todd  

Fifth  Pair  of  Nerves. .  Dr.  Alcock  

Foetus   Dr.  Montgomery. 

Foot,    Bones  and 

Joints  of  

Fool,  Abnormal  Con-  i 

'        ,  cA.T.  S.  Dodd,Esq. 

ditions  of  } 

Foot,  Regions  and  i 
„.     .      „  \A.T.S.Dodd,Esq. 
Muscles  of    5  '  1 


Todd 


81 
98 
111 
144 
117 
154 
171 
207 
229 
231 
235 
257 
260 
203 
267 
268 
316 

338 
347 
350 


}  .S'.  Solly,  Esq  361 


Fore-arm,  Muscles 
and  Regions  of  . 

Fourth  Pair  of  Nerves  Dr.  Alcock   

Ganglion   R.D.Grainger, Esq. 

Gasteropoda   T.  Rymer  Jones,  Esq. 


370 
371 
377 


Gelatin    W.T.  Brande,  Esq. 

Generation.  Organs  >  „  „         „  _, 

'     h       \T.  Rymer  Jones,  Esq. 
of   ' 

Generation   Dr.  Allen  Thomson.. 

Gland   R.D.  Grainger,  Esq. 

Glosso  pharyngeal  ~>  _     _  . , 

J  Dr.  Real  

Nerve  * 

Glutasal  Region  A  T.  S.  Dodd,  Esq. 

Groin,  Region  of  the  Dr.  Todd  

Haamatosiue   Dr.  Rees  

Hand,  Bones  of  the  Dr.  Todd  

Hand,    Abnormal  > 

}  R.  Adams,  Esq  

Conditions  of  the  ' 

Hand,  Muscles  of  >  _  _  ,,,,  _  ,,' 

'  ^F.T.  M'Dougall,  Esq. 

Hand,  Regions  of  the  F.  T.  M'Dougall,  Esq. 
Hearing,  Organ  of. .  T.  W.  Jones,  Esq.  . . 

Hearing   Dr.  Todd  

Heart   Dr.  Reid  

Heart,     on    the  -v 

Arrangement   of  >H.  Searle,  Esq  


the  Fibres  of  the 


s 


Page 
41)4 

400 

424 
480 

194 

500 
503 
503 
505 

510 

519 

523 
529 
564 
577 

619 


Heart,  Abnormal   1  „ 

',.  .        „  ,    \Dr.  Todd  

Conditions  of  the  ' 

Heat,  Animal  Dr.  W.F.Edwards  . 

Hermaphroditism  ..  Dr.  Simpson  

Hernia   W.  II.  Porter,  Esq. 

Hibernation   Dr.  Marshall  Hall  . . 

Hip-Joint,  Normal  >  TT 

.  i  II.  Hancock,  Esq.  . . 

Anatomy  ' 

Hip-Joint,  Abnor-  )  r.    .  ,  „ 

v  k.  Adams,  Esq. 


malConditions  of 

Hyperemia    Dr.  Todd  

Hypertrophy   Dr.  Todd  

Iliac  Arteries   Dr.  Alcock   , 

Innominata  Artery  .  H.  Hancock,  Esq.  . . 

Insecta    G.  Newport,  Esq.  . 

Insectivora   T.  Bell,  Esq  


630 

648 
684 
738 
764 

770 

780 

825 
826 
827 
850 
853 
994 


THE 


CYCLOPAEDIA 


ANATOMY  AND  PHYSIOLOGY. 


DIAPHRAGM  (in  anatomy),  (Jia^ay^a, 
inter,  and  (p^curo-a,  sepio,  claudo  ;  Lat.  dia- 
phragm a  ;  Ital.  diaf'ramma;  Fr.  diaphragms; 
Ger.  Zwerchfell ;  Eng.  midriff),  the  name  given 
to  that  musculo-tendinous  septum  by  which  the 
cavities  of  the  thorax  and  abdomen  are  separated 
from  each  other  in  the  Mammalia. 

Nothing  analogous  to  the  diaphragm  of  mam- 
mals can  be  detected  in  the  Invertebrate  classes 
of  animals  ;  the  function  of  which  it  is  a  princi- 
pal muscularagentin  the  Mammalia,  respiration, 
being  effected  by  the  skin,  intestines,  stigmata, 
trachea1,  gills,  &c.  Most  of  the  Vertebrata, 
however,  exhibit  something  analogous  to  the 
diaphragm.  Thus  in  Fishes  the  muscular  sep- 
tum dividing  the  cavity  of  the  branchial  ap- 
paratus (thorax)  from  the  abdomen  bears  a 
certain  resemblance  to  the  diaphragm.  Birds 
have  muscles  which  proceed  obliquely  upwards 
in  the  form  of  flat  bundles  of  fibres  from  the 
middle  of  the  lower  ribs  to  the  under  part  of 
the  lungs,  where  they  are  lost  in  the  pleura 
covering  these  organs  ;  and  thus  by  their  con- 
traction depress  the  lungs  themselves,  expand 
their  cells,  and  facilitate  the  ingress  of  air 
into  them.  These  muscular  fibres  are  particu- 
larly developed  in  the  parrot.*  But,  as  has 
been  said,  it  is  only  in  Mammalia  that  the 
genuine  diaphragm  is  to  be  found  ;  and  all  the 
animals  of  this  class  possess  it.  The  organ,  as 
might  be  expected,  undergoes  some  modifica- 
tions in  different  families.  In  amphibious  and 
cetaceous  mammalia  it  approximates  to  that  of 
birds.    A  very  strong  and  fleshy  diaphragm  is 

*  C.  G.  Carus,  Comparative  Anatomy. 
VOL.  II. 


attached  to  the  dorsal  side  of  the  cavity  of  the 
trunk  so  low  down  that  it  ascends  considerably 
in  order  to  be  connected  in  a  peculiar  manner 
with  the  upper  and  anterior  extremity  of  the 
abdominal  muscles ;  so  that  the  lungs  lie  be- 
hind rather  than  above  the  diaphragm.'*  In 
the  porpoise  there  is  no  central  tendon.f  The 
horse,  elephant,  rhinoceros,  and  other  animals 
whose  ribs  approach  the  pelvis,  have  a  very- 
extensive  diaphragm,  which  forms  an  elevated 
arch  towards  the  thorax.}  This  shape  is  neces- 
sary to  accommodate  the  bulky  contents  of  the 
abdomen,  without  altering  the  attachments  of 
the  muscle,  which,  as  in  man,  are  connected  to 
the  lowest  ribs.  Some  other  variations  from 
the  structure  and  form  of  the  diaphragm  in  man 
might  be  noticed,  but  they  are  very  unim- 
portant. We  shall  therefore  proceed  to  give  a 
detailed  account  of  the  muscle  in  the  human 
subject. 

Diaphragm  (human  anatomy). — The  dia- 
phragm in  man  is  a  muscle  of  great  importance 
(post  cor  facile  princeps,  Haller),  being  the  chief 
agent  by  which  respiration  is  carried  on,  while 
it  assists  in  the  performance  of  many  other  im- 
portant processes.  It  is  placed  between  the 
thorax  and  abdomen,  forming  a  convex  floor 
to  the  former,  and  a  concave  ceiling  to  the 
latter.  Although  a  single  muscle,  and  situated 
in  the  median  line,  it  is  not  symmetrical ;  the 
right  side  of  it  is  more  extensive  than  the  left. 
Symmetry,  however,  was  not  necessary  in  an 

*  C.  G.  Cams,  Comparative  Anatomy, 
t  Tyson. 

%  Cuvier,  Anat.  Comp.  vol.  iv. 

B 


2 


DIAPHRAGM. 


organ  which  could  exert  no  influence  on  the 
external  form ;  nor  was  it  to  be  expected  in  a 
muscle  which  is  not  wholly  voluntary.  In  this 
article  it  is  intended  to  describe,  1st,  the  form, 
structure,  and  organization  of  the  diaphragm ; 
2nd,  its  uses ;  and,  3rd,  its  malformations  and 
diseases. 


Fig.  I. 


Thoracic  surface  seen  from  behind,  the  vertebrae  being 
removed. 


For  the  convenience  of  description  the  dia- 
phragm is  usually  divided  into  two  portions — 
the  upper,  which  is  called  the  costal,  or  true  or 
greater  muscle  ;  and  the  lower,  which  is  named 
the  vertebral,  or  smaller,  and  is  also  well  known 
as  the  crura  or  pillars.  This  division  is  sanc- 
tioned by  the  situation,  the  shape,  and  the  uses 
of  the  two  portions. 

The  upper  portion,  placed  tranversely,  (sep- 
tum transversum,)  is  thin,  but  of  great  super- 
ficial extent,  being  connected  by  its  margins  to 
the  entire  circumference  of  the  inferior  outlet  of 
the  thorax.  Narrow  between  the  sternum  and 
spine,  it  spreads  out  on  each  side  into  large 
wings,  and  its  outline  bears  some  resemblance 
to  the  figure  of  eight  laid  on  the  side,  thus  od  . 
The  centre  is  tendinous ;  the  border  consists  of 
fleshy  fibres.  The  tendinous  part  (Jig.  1,  T) 
{centrum  tendineum,  s.  nerveum,  s.  phrenicum, 
cordifbrm  tendon)  is  of  considerable  size,  and 
in  shape  resembles  the  trefoil  leaf.  It  presents 
a  large  semicircular  notch  behind  towards  the 
spine,  and  is  deeply  divided  on  its  anterior 
margin  into  three  lobes,  of  which  one  points  for- 
wards and  one  to  each  side.  Of  these  lobes  the 
right  is  usually  the  largest,  the  left  the  smallest; 
the  anterior  is  the  shortest,  and  sometimes  the 
broadest;  the  left  is  the  narrowest  and  often 
the  longest.  But  these  proportions  will  be 
found  to  vary  in  different  individuals.  The 
tendon  is  composed  of  fibres  which  pursue 
various  courses.  The  greater  number  radiate 
from  the  vertebral  notch  ;  these  are  crossed  by 
others  which  run  in  every  direction,  and  which 
seem  to  be  continuous  with  the  muscular 
fibres ;  and  others  again  appear  to  be  laid  on 
the  tendon  as  accessaries,  rather  than  as  con- 
tributing to  its  texture.  These  last  are  most 
distinctly  seen  in  old  men,  and  on  the  under 
surface  of  the  right  lobe.  The  tendinous  centre 
forms  nearly  the  highest  part  of  the  arch.  It  is 
less  curved  than  the  fleshy  portion,  and  more 
fixed  in  its  position.  One  large  opening  pre- 
sents itself  here,  between  the  right  and  middle 
lobes,  through  which  the  vena  cava  passes  to 
the  heart. 

From  the  anterior  and  lateral  margins  of  this 
tendon  the  muscular  fibres  pass  off  in  arches, 
to  be  inserted  into  all  the  base  of  the  thorax  by 
digitations  which  mix  with  those  of  the  trans- 
versus  abdominis. 

Beginning  in  front,  we  find  two  slender  fasci- 
culi running  downwards  and  forwards  to  the 
ensiform  cartilage.  These  are  separated  from 
each  other  by  a  line  of  cellular  tissue,  marking 
the  median  line  of  the  muscle;  sometimes  one 
or  both  of  these  bundles  may  be  absent,  pro- 
bably resulting  from  an  arrest  of  formation. 
To  the  outside  of  these,  on  each  side,  a  con- 
siderable triangular  interval  exists,  where  the 
pleura  and  peritoneum  are  separated  only  by 
cellular  substance.  Here  some  small  branches 
of  the  internal  mammary  artery  pass  to  the  ab- 
domen ;  and  in  this  situation  fluids  might  easily 
find  their  way  from  the  cellular  tissue  of  one 
cavity  to  that  of  the  other.  The  fibres  next  in 
order,  bounding  these  spaces  externally,  are 
much  longer ;  they  pass  outwards  and  down- 
wards to  the  seventh  rib,  and  are  inserted  by  a 


DIAPHRAGM. 


A, 


broad  digitation  into  the  point  of  the  bone  and 
into  about  one  half  of  the  adjoining  portion  of 
its  cartilage.  The  next  fibres  are  still  longer, 
usually  the  longest  of  all;  they  run  outwards, 
then  downwards,  forming  the  second  digitation, 
which  is  attached  in  a  similar  manner  to  the 
eighth  rib.  The  following  fibres  becoming 
shorter  as  they  approach  the  spinal  notch,  go  to 
the  ninth  and  tenth  ribs,  and  are  similarly  con- 
nected. The  succeeding  ones,  still  shorter, 
proceed  to  the  eleventh  and  twelfth,  and  attach 
themselves  to  a  considerable  portion  of  their 
length.  In  the  two  lowest  intercostal  spaces 
the  diaphragm  and  transversus  abdominis  are 
united  by  a  common  aponeurosis,  which  is  very 
thin ;  and  here  it  is  not  very  unusual  to  meet 
with  a  deficiency  in  the  diaphragm.  The  thin 
portion  of  the  muscle,  near  to  the  crura,  has  its 
short  fleshy  fibres  inserted  into  the  ligamentum 
arcuatum  externum.*  (JVg.  1,  d.)  This  last  appel- 
lation is  bestowed  on  a  thin  aponeurosis  which 
stretches  from  the  inferior  margin  of  the  last  rib 
to  the  point  of  the  transverse  process  of  the  first 
lumbar  vertebra.  In  reality  it  is  nothing  more 
than  the  anterior  layer  of  the  tendon  of  the 
transversus  abdominis  which  lies  in  front  of  the 
quadratus  lumborum  muscle,  and  is  connected 
to  the  lowest  rib.  By  pulling  the  rib  outwards 
the  aponeurosis  is  projected  into  a  fold  which 
looks  like  a  ligament.  It  is  designated  ex- 
ternum to  distinguish  it  from  another  that  is 
much  stronger  and  more  truly  ligamentous, 
which  arches  over  the  psoas  magnus  muscle, 
is  attached  to  the  transverse  process  of  the 
first  lumbar  vertebra  (just  where  the  former 
ends),  and  to  the  body  of  the  second.  The 
latter  is  known  as  the  ligamentum  arcuatum 
internum  f  (fig.  it  is  also  called  the  true, 

and  the  external  the  false, — names  derived  from 
their  structure. 

The  vertebral  or  smaller  muscle  of  the  dia- 
phragm is  placed  almost  perpendicularly.  The 
fibres  pass  off  from  the  concave  margin  of  the 
tendon  which  is  turned  to  the  spine.  They  run 
downwards  and  a  little  backwards  at  first,  then 
along  the  lumbar  vertebra,  into  which  they  are 
principally  inserted.  The  shortest  and  most 
external  of  them  go  to  the  internal  ligamentum 
arcuatum ;  but  the  greater  number  form  two 
large  and  long  fasciculi,  the  crura,  or  pillars,  or 
appendices  of  the  diaphragm. 

The  right  crus  is  longer  and  thicker  than  the 
left,  and  is  nearer  to  the  middle  line.  It  is 
attached  by  tendinous  slips  to  the  bodies  of  the 
three  (often  of  the  four)  superior  lumbar  ver- 
tebrae and  to  the  intervertebral  substances.  The 
left  is  attached  in  a  similar  way,  but  never  de- 
scends so  low.  Both  become  smaller  as  they 
pass  down,  the  more  external  fibres  being 
soonest  inserted.  The  muscular  bundles,  on 
quitting  the  cordiform  tendon,  separate  imme- 
diately from  each  other,  to  permit  the  oesopha- 
gus to  pass  into  the  abdomen,  and  unite  again 
behind  that  tube.  Here  a  crossing  or  inter- 
lacing of  the  fibres  takes  place,  a  considerable 
bundle  descending  from  the  left  side  of  the 


*  Arcus  tendinous  exterior,  Scnac. 
t  Arcus  tendineus  interior,  Id. 


oesophagus  to  the  right  crus,  and  a  smaller  one 
from  the  right  side  to  the  left  crus.  In  general 
the  latter  is  placed  anteriorly  ;  and  occasionally 
two  bundles  descend  from  each  side  alternating 
with  their  opposites.  The  fleshy  fibres  again 
separate  on  a  level  with  the  lower  edge  of  the 
last  dorsal  vertebra  to  allow  the  aorta  to  pass, 
and  they  continue  afterwards  distinct. 

The  foramina  or  openings  which  present 
themselves  in  this  septum  require  to  be  noticed. 
Three  large  ones  have  been  already  mentioned ; 
but  as  the  organs  which  they  transmit  are  of 
great  importance,  they  deserve  more  minute  at- 
tention. The  first  is  situated  in  the  tendon  of 
the  diaphragm,  toward  its  posterior  part,  a  little 
to  the  right  of  the  centre  (Jig A,  c).  It  corre- 
sponds to  the  line  of  division  between  the  middle 
and  right  lobes.  Its  shape  is  quadrangular, 
(foramen  quadratum,)  having  an  anterior,  a  pos- 
terior, a  right  and  a  left  edge.  The  right  is  the 
longest,  the  anterior  the  shortest,  and  these  two 
often  appear  to  form  but  one.  The  inferior 
vena  cava  passes  through  this  opening  and  im- 
mediately empties  itself  into  the  right  auricle  of 
the  heart.  The  vein  is  firmly  connected  to  the 
foramen  by  means  of  thin  aponeuroses  sent  off 
from  the  tendinous  margins;  the  posterior 
margin  sending  fibres  upwards,  the  lateral 
downwards,  and  the  anterior  in  both  directions. 
This  is  the  highest  opening  in  the  diaphragm, 
being  on  a  level  with  the  lower  edge  of  the 
ninth  dorsal  vertebra  and  fifth  rib.  As  the 
boundaries  of  it  are  entirely  tendinous  they 
cannot  act  on  the  vein  themselves,  and  the  ac- 
tion of  the  muscular  fibres  only  serves  to  keep 
it  dilated.  Some  branches  of  the  phrenic  nerve 
accompany  this  vein. 

A  little  to  the  left  of  the  median  line,  and 
close  behind  the  central  tendon,  we  find  an 
opening  of  an  elliptical  form  through  which  the 
oesophagus  and  pneumogastric  nerves  pass  (fig. 
i,e).  Its  major  axis,  two  inches  in  length,  is  di- 
rected obliquely  downwardsand  backwards.  The 
borders  are  entirely  muscular,  at  least  very  ge- 
nerally, for  it  sometimes  happens  that  the  ante- 
rior extremity  is  bounded  by  the  cordiform  ten- 
don. It  results  from  a  separation  of  the  fibres 
which  are  descending  to  constitute  the  crura, 
and  may  be  said  to  lie  between  the  crura.  The 
crossing  or  interlacing  of  the  fibres  which  takes 
place  just  behind  it  must  enable  them  to  shut 
up  this  opening  completely  when  they  act 
strongly.  This  foramen  is  on  a  level  with  the 
tenth  dorsal  vertebra,  its  upper  and  lower  an- 
gles corresponding  to  the  planes  of  the  upper 
and  lower  surfaces  of  that  bone. 

About  two  inches  below  the  inferior  point 
of  the  oesophageal  opening  the  aorta  may  be 
seen,  coming  out  of  the  thorax,  opposite  the 
lower  edge  of  the  last  dorsal  vertebra  (fig.  1,  a.) 
This  great  vessel  enters  the  abdomen  by  a  canal 
which  is  formed  posteriorly  by  bone,  anteriorly 
by  the  decussating  fibres,  and  on  either  side  by 
the  crura  of  the  diaphragm.  These  crura,  after 
passing  along  the  sides  of  the  artery,  almost 
meet  behind  it  by  their  tendinous  expansions 
lower  down.  The  margin  of  the  aortic  opening 
is  bordered  with  tendon,  and  the  fleshy  fibres 
are  so  connected  with  it  that  their  action  does 

B  2 


4 


DIAPHRAGM. 


not  at  all  diminish  the  size  of  the  passage 
Along  with  the  aorta  and  to  its  right  side  we 
see  the  vena  azygos  and  thoracic  duct  passing 
into  the  thorax. 

Some  other  foramina  transmit  vessels  and 
nerves,  but  they  are  very  small  and  irregular. 
The  sympathetic  nerve  usually  passes  with  the 
psoas  muscle  under  the  internal  ligamentum 
arcuatum.  The  right  splanchnic  slips  out  of 
the  thorax  between  the  fibres  of  the  right  eras, 
at  a  point  internal,  superior,  and  anterior  to  the 
sympathetic.  The  left  splanchnic  comes  in  the 
same  way,  or  more  frequently  with  the  aorta. 
The  lesser  splanchnic  passes  at  the  outer  side 
of  the  former,  separated  from  it  by  a  few  fibres. 
Behind  the  external  ligamentum  arcuatum  the 
last  dorsal  nerve  may  be  seen.  Filaments  of 
the  phrenic  nerve  pierce  the  muscle  in  several 
places,  principally  its  tendinous  part,  and  some 
pass  through  the  opening  for  the  vena  cava. 
And  branches  of  the  internal  mammary  artery 
creep  through  those  cellular'  spaces  which  are 
left  between  the  xiphoid  cartilage  and  first 
costal  attachment. 

The  upper  muscle  of  the  diaphragm  is  lined 
for  the  most  part  of  its  under  surface  by  the 
peritoneum,  and  on  its  upper  by  the  pleurae 
and  pericardium  ;  being  thus  placed  between 
serous  membranes.  In  some  points  the  peri- 
toneum is  reflected  off  to  form  ligaments  for 
the  liver,  and  there  this  last  organ  comes  in 
contact  with  the  muscle.  The  same  thing  oc- 
curs to  a  small  extent  in  the  case  of  the  kid- 
neys. The  upper  surface  too  is  for  a  little  way 
all  along  its  margin  destitute  of  serous  covering, 
and  in  contact  with  the  ribs,  intercostal  mus- 
cles, quadratus  lumborum,  psoas,  and  triangu- 
laris sterni.  Over  the  serous  membranes  on 
the  thoracic  surface  we  find  on  each  side  the 
base  of  the  lungs,  and  in  the  centre  the  heart 
resting  on  the  middle  lobe  of  the  tendon  and 
on  some  muscular  fibres  to  its  right.  The  ab- 
dominal surface  is  related  to  the  liver,  stomach, 
spleen,  and  kidneys. 

The  inferior  muscle  of  the  diaphragm  has 
one  surface  turned  back  to  the  spinal  column, 
and  in  contact  with  it  and  with  a  little  of  the 
aorta;  the  other  surface  looks  forwards,  and  is 
covered  by  the  suprarenal  capsules,  the  semi- 
lunar ganglia,  and  various  nerves,  the  aorta  and 
its  principal  branches,  the  ascending  cava,  the 
commencement  of  the  abdominal  vena  porta 
and  its  tributaries,  the  pancreas,  stomach,  duo- 
denum, and  occasionally  other  parts.  Little 
or  no  peritoneum  can  touch  this  portion. 

Arteries. —  A  muscle  of  so  much  importance 
in  the  animal  economy  as  the  diaphragm,  and 
so  perpetually  in  action,  requires  a  large  supply 
of  blood.  This  it  receives  through  numerous 
channels  and  from  distinct  sources  ;  and  as  all 
its  vessels  inosculate  freely  in  its  substance,  no 
failure  in  the  supply  can  well  occur.  The 
phrenic  and  internal  mammary  are  distributed 
to  its  middle ;  the  same  vessels,  with  the  in- 
tercostal, the  lumbal,  and  some  small  aortic 
twigs,  feed  the  circumference. 

Veins. — The  veins  of  the  diaphragm  accom- 
pany the  arteries  as  in  other  parts  of  the  body  ; 
each  artery  having  one  or  two  vena;  comites. 


The  principal  veins,  however,  correspond  to  the 
phrenic  artery,  and  pour  their  blood  into  two 
trunks,  a  right  and  a  left,  which  empty  them- 
selves into  the  cava.  They  are  usually  seen 
on  the  under  surface  of  the  tendon,  sometimes 
on  the  upper;  or  there  may  be  two  above  and 
two  below.  Occasionally  they  lie  between  the 
two  surfaces,  so  that  their  entrance  into  the 
cava  is  not  seen  ;  and  in  some  cases  they  join 
the  hepatic  veins. 

Lymphatics. — The  diaphragm  is  furnished 
with  lymphatic  vessels  as  other  muscles,  but 
there  is  nothing  peculiar  in  them.  They  are 
not  easily  demonstrated,  as  they  do  not  form 
any  very  distinct  trunks,  but  join  with  the 
lymphatics  of  the  neighbouring  organs. 

Nerves. — The  diaphragm  receives  a  great 
number  of  nerves.  The  lumbar  send  twigs  to 
the  crura,  the  lower  dorsal  to  the  broad  muscle, 
and  there  is  a  phrenic  plexus  sent  off  from  the 
solar,  which  accompanies  the  phrenic  arteries, 
and  distributes  its  numerous  and  delicate  fila- 
ments with  extreme  minuteness  to  the  under 
surface  of  the  muscle.  From  the  plexus  which 
the  eighth  pair  forms  on  the  stomach,  we  trace 
also  some  fine  filaments.  But  the  chief  and 
most  important  nerves  are  the  phrenic.  The 
phrenic  nerve  arises  from  the  cervical  plexus ; 
its  principal  origin  is  from  the  fourth  cervical 
nerve,  to  which  there  is  usually  joined  a  small 
twig  from  the  third.  It  runs  down  along  the 
anterior  scalenus,  and  gets  into  the  thorax  be- 
tween the  subclavian  artery  and  vein.  In  the 
neck  it  generally  receives  filaments  from  each 
cervical  nerve.  As  it  enters  the  thorax,  it  com- 
municates with  the  inferior  cervical  ganglion, 
and  gets  a  filament  from  the  descendens  noni 
and  the  pneumogastric.  The  nerve  thus  formed 
is  conducted  by  the  mediastinum  and  pericar- 
dium, in  front  of  the  root  of  the  lung,  to  the 
diaphragm;  the  left  being  a  little  longer  than 
the  right,  and  thrown  somewhat  further  back 
by  the  position  of  the  heart. 

It  enters  the  diaphragm  at  the  anterior  edge 
of  the  tendon  in  six  or  seven  branches,  the 
largest  of  which  pass  backwards.  Some  go 
through  the  muscle,  ramify  on  its  under  sur- 
face, and  anastomose  with  the  solar  plexus ; 
and  one  may  usually  be  traced  through  the 
opening  for  the  cava  on  to  that  plexus.  The 
influence  which  these  nerves  exert  on  die  organ 
will  presently  be  adverted  to. 

Uses. — The  chief  use  of  the  diaphragm  is  to 
assist  in  the  function  of  respiration,  and  it  will 
be  found  to  be  the  principal  agent  in  the  me- 
chanical part  of  that  process.  By  its  action 
the  thoracic  cavity  is  enlarged  from  above 
downwards,  whilst  its  circumference  is  in- 
creased by  the  intercostal  and  other  muscles. 

When  the  diaphragm  acts,  the  entire  muscle 
descends,  pushing  the  abdominal  viscera  down- 
wards and  forwards ;  but  its  different  portions 
descend  very  unequally.  The  tendinous  centre 
is  nearly  fixed,  and  the  crura  are  incapable  of 
much  change  of  position ;  it  is  only  in  the 
broad  lateral  expansions  that  the  motion  is  very 
apparent.  The  muscular  fibres  of  these  when 
relaxed  are  pressed  upwards,  and  present 
arches,  convex  to  the  thorax,  and  rising  even 


above  the  tendon ;  but  when  brought  into  ac- 
tion, each  fibre  approaches  to  a  right  line,  which 
runs  obliquely  down  from  the  tendon  to  its 
point  of  insertion.  Thus,  instead  of  a  great 
arch  we  have  a  number  of  inclined  planes,  very 
short  in  front,  very  long  at  the  sides,  and  of 
intermediate  length  further  back,  all  surmount- 
ed by  a  tendinous  platform.  The  base  of  the 
lung  resting  on  the  muscle  descends  with  it ; 
the  liver,  stomach,  spleen,  and  all  the  moveable 
viscera  of  the  abdomen  are  pressed  downwards 
and  forwards  against  the  abdominal  muscles. 
When  the  diaphragm  descends,  therefore,  in- 
spiration takes  place  by  the  rush  of  air  into  the 
expanding  thorax ;  when  it  ascends  expiration 
is  the  result,  the  air  being  forced  out.  In  the 
former  case  the  diaphragm  is  active ;  in  the 
latter  it  is  completely  passive,  following  the  re- 
siliency of  the  lungs,  and  pressed  up  by  the 
action  of  the  abdominal  muscles  on  the  viscera 
beneath.*  The  central  tendon  descends  very 
little  on  account  of  its  attachment  to  the  peri- 
cardium :  descent  here  would  be  useless  or 
worse;  but  the  lateral  portions  on  which  the 
broad  bases  of  the  lungs  rest,  freely  change  their 
place,  and  allow  of  considerable  expansion  of 
the  thorax  where  it  is  most  required. 

From  viewing  the  insertion  of  the  diaphragm 
into  the  lower  ribs  it  might  be  thought  that 
they  would  be  drawn  in  by  its  action,  and  the 
capacity  of  the  thorax  thereby  diminished  more 
than  increased;  but  the  intercostals  prevent 
this  occurrence  by  acting  at  the  same  moment 
to  elevate  and  draw  out  the  ribs. 

The  crura,  besides  acting  in  common  with 
the  broad  muscle  in  enlarging  the  thorax,  serve 
to  fix  the  central  tendon,  and  prevent  it  from 
being  drawn  to  either  side  by  the  irregular  ac- 
tion of  either  half  of  the  muscle,  or  forced  too 
high  up.  They  may  also  by  their  fibres  conti- 
nued on  each  side  of  the  oesophageal  orifice, 
and  contracting  in  concert  with  the  rest  of  the 
muscle,  close  that  opening,  and  thus  prevent 
regurgitation  from  the  stomach  at  the  time 
when  this  viscus  is  pressed  upon  by  the  descent 
of  the  diaphragm. 

The  extent  to  which  the  diaphragm  descends 
is  not  great.  The  central  tendon  will  not  admit 
of  much  displacement  in  the  normal  state  of 
the  parts,  and  the  shape  and  motions  of  the 
liver  show  that  even  the  great  ate  do  not  un- 
dergo much  alteration.  Haller  indeed  says 
that  he  saw  the  diaphragm  descend  so  much  in 
violent  inspiration  as  to  present  a  convexity  to- 
wards the  abdomen. f  But  this  is  quite  incre- 
dible. The  utmost  muscular  effort,  if  there 
were  no  fixed  point  in  its  centre,  could  only 
obliterate  the  arch;  but  even  this  we  think  im- 
possible on  account  of  its  attachments.  We 
find  on  some  occasions  one  side  of  the  dia- 
phragm act  independently  of  the  other. 

The  importance  of  the  diaphragm  in  respira- 
tion is  shewn  by  the  difficulty  with  which  that 

,,r  *  Senac  says  the  anterior  fibres  assist  in  expira- 
tion by  drawing  the  ribs  inwards  and  backwards. 
Acad,  des  Sciences,  1729. 

t  In  violentissima  respiratione  omnino  vidi  deor- 
sum  versus  abdomen  diaphragma  convexum  reddi. 
Haller,  Elcm.  I'hys.  lib.  viii.  sect.  1. 


IAGM.  5 

function  is  performed  when  the  actions  of  the 
muscle  are  interfered  with.  Ascites  and  tu- 
mours in  the  abdomen  render  the  breathing 
shorter;  even  a  full  meal  will  have  this  effect, 
owing  to  the  impediments  to  the  descent  of  the 
diaphragm.  If  the  phrenic  nerves  be  divided 
in  a  living  animal,  great  difficulty  of  breathing- 
follows,  the  entire  labour  of  respiration  being 
thrown  on  the  muscles  which  elevate  the  ribs. 
If  the  spinal  marrow  be  divided  above  the, 
giving  off  of  the  phrenic  nerves,  respiration 
ceases  at  once,  but  not  so  if  divided  imme- 
diately below  that  point ;  and  in  a  case  of  fatal 
dyspnoea  Beclard  could  find  no  cause  but  a 
tumour  on  one  of  the  phrenic  nerves. 

Besides  the  part  which  it  plays  in  respira- 
tion, it  is  probable  that  the  diaphragm,  by  its 
ordinary  motions,  exerts  a  beneficial  influence 
on  the  digestive  organs.  The  liver  must  be 
more  or  less  affected  by  it  in  its  secretion,  and 
the  gall-bladder  is  supposed  to  receive  from  it 
a  compression  which  in  some  degree  makes 
amends  for  the  want  of  muscular  fibres,*  whilst 
the  agitation  of  the  hollow  viscera  will  favour 
the  transmission  of  their  contents. 

The  chyle  in  the  lacteals  and  thoracic  duct 
may  also  receive  an  impulse  from  the  dia- 
phragm. 

Some  anatomists  were  of  opinion  that  the 
venous  circulation  in  the  abdomen  was  also 
assisted  by  the  pressure,  but  the  absence  of 
valves  in  these  vessels  must  prevent  them  from 
deriving  any  assistance  from  alternate  compres- 
sion and  relaxation.  It  acts  powerfully,  how- 
ever, on  the  venous  circulation  of  the  whole 
system  by  the  vacuum  which  it  has  a  tendency 
to  form  in  the  thorax. 

The  nerves  which  pass  through  the  dia- 
phragm, as  the  par  vagum,  sympathetics,  and 
splanchnics,  were  formerly  supposed  to  suffer 
compression,  and  the  alternate  transmission  and 
interruption  of  the  nervous  influence,  it  was 
thought,  could  account  for  the  pulsations  of 
the  heart  and  the  vermicular  motions  of  the 
intestines.  But  all  this  is  too  obviously  erro- 
neous to  require  comment. 

The  diaphragm  assists,  though  rather  as  a 
passive  instrument,  in  the  expulsion  of  the 
urine,  feces,  &c.  For  this  purpose  the  thorax 
is  filled  with  air,  the  rima  glottidis  is  closed, 
and  the  diaphragm  forms  a  resisting  surface 
against  which  the  abdominal  muscles  press  the 
hollow  viscera,  and  force  out  their  contents 
wherever  an  exit  is  afforded  them. 

The  diaphragm  is  more  or  less  engaged  in 
hiccup,  yawning,  sighing,  sobbing,  groaning, 
which  are  all  actions  connected  in  various 
ways  with  the  function  of  respiration,  and  some 
of  them  more  especially  dependent  on  the  dia- 
phragm, particularly  hiccup,  which  is  an  explo- 
sive inspiration,  in  which  the  diaphragm  acts 
involuntarily  by  a  short  and  sudden  effort,  a 
sound  being  at  the  same  time  produced  in  the 
larynx. 

The  diaphragm  also  performs  an  important 
part  in  vomiting.  A  full  inspiration  precedes 
this  act,  then  the  glottis  is  closed,  and  the  ab- 

*  Senac. 


6 


DIGESTION. 


dominal  muscles  forcibly  press  the  stomach 
against  the  diaphragm,  so  as  to  assist  the  anti- 
peristaltic motion  of  that  viscus.  Magendie 
made  experiments  to  show  that  unless  the  dia- 
phragm or  abdominal  muscles  acted  on  the 
stomach,  no  vomiting  could  take  place.  He 
went  too  far,  however,  when  he  attributed  the 
entire  result  to  them.  Substituting  a  pig's 
bladder  for  the  stomach,  he  injected  tartar 
emetic  into  the  veins,  and  vomiting  followed. 
But  he  forgot  that  pressure  might  readily 
empty  a  dead  bladder  and  have  little  effect  on 
a  living  stomach.  And  that  such  is  the  case 
we  may  be  certain,  else  every  cough  would 
evacuate  the  stomach. 

Lastly,  the  diaphragm  acts  the  part  of  a  sep- 
tum or  mediastinum  to  separate  the  two  great 
cavities  between  which  it  is  placed.  When 
this  septum  is  wanting,  the  abdominal  viscera 
get  into  the  thorax,  and  in  such  cases  the  lungs 
are  constantly  found  in  a  rudimentary  state  : 
their  further  evolution  being  impeded  by  the 
pressure  exerted  on  them  by  the  intruding 
viscera.* 

It  has  been  stated  that  the  oesophageal  open- 
ing may  be  closed  by  those  fibres  of  the  crura 
which  curve  round  it.  The  other  openings,  as 
the  aortic,  and  that  for  the  ascending  cava,  can- 
not be  diminished  by  the  efforts  of  the  muscle. 
This  is  plain  from  the  tendinous  margins  which 
they  present,  and  the  manner  in  which  the  mus- 
cular fibres  are  attached  to  their  borders. 

We  have  not  mentioned  some  of  the  uses 
which  the  ancients  ascribed  to  the  diaphragm — 
as,  that  it  is  the  seat  of  the  passions,f  that  it 
prevented  noxious  vapours  from  rising  into  the 
thorax,  that  it  fanned  the  hypochondria,  and  so 
forth.  These  are  too  fanciful  to  demand  serious 
notice. 

Malformations  and  diseases.  —  The  dia- 
phragm may  be  absent  in  whole  or  in  part  by 
congenital  malformation.  In  the  very  young 
foetus  the  thorax  and  abdomen  form  one  cavity, 
as  in  birds,  reptiles,  and  fishes ;  and  the  deve- 
lopment of  the  diaphragm,  as  of  most  other 
organs,  is  by  a  process  of  growth  from  the  cir- 
cumference to  'the  centre.  If,  therefore,  an 
arrest  of  formation  occur  at  a  very  early  period 
of  foetal  existence,  the  muscle  may  be  entirely 
wanting;  if  at  a  later  period,  some  deficiency 
will  be  found  at  or  near  the  centre.  An  exam- 
ple of  the  total  absence  of  the  diaphragm  was 
dissected  by  Diemorbroeck.  The  subject  lived 
to  the  age  of  seven  years  without  suffering  any 
inconvenience  except  a  frequent  cough. J  Con- 
genital deficiencies  near  its  middle  are  not  very 
rare.  They  are  observed  oftener  towards  the 
left  than  the  right  side,  and  are  always  accom- 
panied with  a  protrusion  of  the  abdominal 
viscera  into  the  thorax,  not  vice  versa.  The 
development  of  the  thoracic  viscera  is  impeded 
by  this  intrusion,  and  they  remain  more  or  less 

*  Andral's  Pathological  Anatomy,  tr.  by  Town- 
send  and  West,  vol.  i. 

t  The  word  phrenic,  used  with  reference  to  the 
diaphragm,  as  phrenic  nerve,  phrenic  centre,  &c. 
has  its  origin  in  this  opinion,  <J>p£Vif,  a  <f(r,v,  mens, 
tanquam  mentis  sedes. 

$  Diet,  des  Sciences  Med.  art.  Diaphragme. 


rudimentary.  It  sometimes  happens  that  the 
natural  openings  of  the  diaphragm  are  too 
large,  and  then  protrusions  or  herniee  are  apt  to 
occur  by  the  sides  of  the  tubes  which  they 
were  intended  alone  to  transmit. 

Openings  frequently  occur  in  consequence 
of  disease  or  violence.  Ulcers  often  make  a 
perforation,  and  it  is  common  enough  to  see  an 
abscess  of  the  liver  make  its  way  into  the  lung 
through  the  diaphragm.  The  writer  lately  saw 
an  abscess,  which  formed  in  the  gastrosplenic 
omentum,  take  the  same  course.  Wounds  often 
penetrate  the  diaphragm,  and  it  is  remarkable 
that  however  small  they  may  be,  a  ventral 
phrenic  hernia  is  sure  to  follow. 

The  diaphragm  has  been  suddenly  ruptured 
during  violent  muscular  efforts,  vomiting,  falls, 
&c.  and  instant  death  has  usually  followed. 
Various  examples  of  such  ruptures  are  recorded 
in  the  Dictionnaire  des  Sciences  Med.  art. 
Diaphragme.  The  countenance  in  all  such 
cases  assumes  the  peculiar  expression  or  grin 
called  risns  Sardonicus. 

The  diaphragm  is  subject  to  attacks  of  in- 
flammation, which,  in  almost  every  case,  is 
communicated  to  it  by  the  adhering  pleura  or 
peritoneum.  It  is  indeed  usually  confined  to 
one  or  other  of  these  serous  membranes,  chiefly 
the  pleura,  and  does  not  affect  the  muscular 
fibre.  It  is,  notwithstanding,  termed  diaphrag- 
mitis.  Hippocrates  called  it  phrenitis,  and 
Boerhaave  changed  the  name  to  paraphrenitis, 
to  distinguish  it  from  a  well-known  cerebral 
affection. 

Gangrene,  collections  of  pus,  tumours,  &c.  are 
occasionally  met  with,  and  are  of  very  difficult 
diagnosis. 

Cartilaginous  and  osseous  deposits  have  been 
found  on  both  sides  of  the  diaphragm  in  the 
subserous  cellular  tissue. 

The  diaphragm  is  often  considerably  dis- 
placed upwards  or  downwards.  In  ascites, 
and  in  consequence  of  diseases  of  the  liver  and 
of  abdominal  tumours,  it  may  be  pushed  up  to 
the  second  rib  on  one  side ;  in  thoracic  affec- 
tions again  it  has  been  so  pushed  down  as  to 
become  convex,  in  part  of  its  extent,  towards 
the  abdomen.  Senac  mentions  a  case  of  great 
enlargement  of  the  heart  which  caused  the  cen- 
tral tendon  to  be  buried  in  the  abdomen,  it 
being  formed  into  a  kind  of  pouch.*  Dr.  W. 
Stokes  found  the  left  ala  convex  towards  the 
abdomen  in  emphysema  of  the  lungs, f  and  it 
is  known  to  yield  extensively  to  the  pressure  of 
fluid  in  cases  of  empyema,  more  especially  if 
the  pleura  covering  it  has  been  much  engaged, 
as  the  same  accurate  observer  has  noticed  and 
explained. 

For  Bibliography  see  that  of  Anatomy  (Intro, 
duction). 

( Charles  Benson.) 

DIGESTION.  (Fr.  digestion;  Germ.  Ver- 
dauung ;  Ital.  digestione.)  This  term  is  em- 
ployed in  Physiology  to  designate  that  func- 
tion by  which  alimentary  matter  is  received 

*  Acad,  des  Sciences,  Mem.  1729. 
t  Dublin  Med.  Journal,  vol.  ix.  p.  37. 


DIGESTION. 


7 


into  an  appropriate  organ,  or  set  of  organs, 
and  where  it  is  subjected  to  a  specific  action, 
which  adapts  it  for  the  purpose  of  nutrition.* 
In  its  original  and  technical  sense  this  action 
was  confined  to  the  stomach,f  but  it  is  gene- 
rally applied  more  extensively,  so  as  to  include 
a  number  of  distinct  operations,  and  a  suc- 
cession of  changes,  which  the  food  experiences, 
after  it  has  been  received  into  the  stomach, 
until  a  portion  of  its  elements  are  separated 
from  the  mass,  and  are  conveyed,  by  means  of 
the  lacteals,  to  the  bloodvessels. 

In  the  following  article  we  shall  employ  the 
term  in  its  most  extensive  acceptation,  and 
shall  regard  the  whole  as  one  function,  the 
successive  steps  of  which  are  intimately  and 
necessarily  connected  together,  and  each  of 
them  essential  to  the  completion  of  the  whole.J 
We  shall  commence  by  a  description  of  the 
organs  of  digestion,  we  shall  next  give  an  ac- 
count of  the  nature  of  the  substances  usually 
employed  as  food  ;  in  the  third  place  we  shall 
trace  the  successive  changes  which  the  food 
experiences  in  the  different  parts  of  the  pro- 
cess; in  the  fourth  place  we  shall  examine 
some  of  the  hypotheses  that  have  been  pro- 
posed to  explain  these  various  operations,  and 
shall  conclude  by  some  remarks  on  certain 
affections  of  the  digestive  organs,  which  are 
connected  with,  or  dependant  upon,  their 
functions. 

I.  Description  of  the  organs  of  digestion. — 
The  organs  of  digestion,  taken  in  their  most 
comprehensive  sense,  may  be  arranged  under 
three  divisions :  the  first,  by  which  the  aliment 
is  prepared  for  the  chemical  change  which  it  is 
afterwards  to  experience,  and  is  conveyed  into 
the  stomach,  being  principally  of  a  mechanical 
nature ;  secondly,  what  have  been  more  ex- 
clusively termed  the  proper  digestive  organs, 
where  the  aliment  receives  its  appropriate 
chemical  changes;  and  lastly,  those  organs 
by  which,  after  the  nutritive  substance  thus 
elaborated  has  been  separated  from  the 
mass,  in  order  to  be  conveyed  into  the 
blood,  the  residuary  matter  is  expelled  from 
the  system.§ 

*  The  term  appears  to  have  been  originally  bor- 
rowed from  the  chemists,  or  the  chemical  physio- 
logists, who  supposed  that  the  aliment  was  ma- 
cerated in  the  stomach  precisely  in  the  same 
manner  as  substances  are  said  to  be  digested  in 
various  operations  in  the  laboratory.  It  was  a  term 
very  frequently  employed  by  Van  Helmont. — See 
Castelli,  Lexicon,  "  Diqestio." 

t  Cullen's  Physiol.  §201. 

X  Magendie  divides  the  process  of  digestion  into 
eight  distinct  actions  :  1,  the  reception  of  the  food  ; 
2,  mastication  ;  3,  insalivation  ;  4,  deglutition  ;  5, 
the  action  of  the  stomach ;  6,  of  the  smaller  in- 
testines;  7,  of  the  large  intestines;  8,  expulsion 
of  the  faxes.  Phys.  t.  ii.  p.  33.  Adelon  and 
Chaussier  arrange  them  under  seven  heads  :  appe- 
tition,  gustation,  mastication,  deglution,  chymilica- 
tion,  chylification,  and  defalcation.  Diet.  Sc.  Med. 
t.  ix.  p.  357. 

§  Adelon  considers  the  digestive  organs  to  con- 
sist of  six  essential  parts  :  the  mouth,  the  pharynx 
and  oesophagus,  the  stomach,  the  duodenum,  the 
small  intestines,  and  the  large  intestines.  Diet. 
Sc.  Med.  t.  ix.  p.  355. 


In  the  higher  orders  of  animals,  where  the 
functions  are  more  numerous,  and  more  varied 
in  their  nature,  we  find  them  to  be  so  inti- 
mately connected  together,  and  dependent  on 
each  other,  that  it  is  impossible  for  any  one 
of  them  to  be  suspended  without  the  derange- 
ment of  the  whole.  But  as  we  descend  to 
animals  of  a  less  perfect  and  complicated 
structure,  the  functions  are  considerably  re- 
duced in  number,  and  seem  also  to  be  less 
intimately  connected,  so  that  certain  of  them 
are  either  altogether  wanting,  or  are  performed, 
although  imperfectly,  by  other  organs,  which 
are  not  exclusively  appropriated  to  them. 
Thus  we  observe  that  some,  even  of  the  parts 
which  are  the  most  essential  to  human  ex- 
istence, as  the  brain,  the  heart,  and  the  lungs, 
are  not  to  be  found  in  many  very  extensive 
classes  of  animals,  some  of  the  functions  be- 
longing to  these  organs  being  entirely  deficient, 
or  being  effected  in  a  more  simple  or  a  less 
complete  manner,  by  a  less  complicated  ap- 
paratus. As  we  descend  still  lower  in  the 
scale,  we  find  the  functions  still  more  restricted 
and  simplified,  until  we  arrive  at  the  lowest 
term  which  would  appear  to  be  compatible 
with  the  existence  of  an  organized  being,  where 
no  functions  remain  but  those  which  seem  to 
be  essential  to  the  original  formation  of  the 
animal  and  to  its  subsequent  nutrition.  That 
some  apparatus  of  this  description  is  abso- 
lutely essential  may  be  concluded,  both  from 
the  consideration,  that  the  nutritive  matter 
which  is  received  into  the  system  must  un- 
dergo a  certain  change,  either  chemical  or 
mechanical,  before  it  can  be  employed  for  this 
purpose,  as  well  as  from  the  fact,  that  a  sto- 
mach, or  something  equivalent  to  it,  has  been 
found  to  be  the  circumstance,  which  is  the 
most  characteristic  of  animal,  as  distinguished 
from  vegetable  life.*  Accordingly,  with  a  very 
few  exceptions,  and  those  perhaps  depending 
rather  upon  the  inaccuracy  of  our  observation, 
than  upon  the  actual  fact,  it  is  generally  ad- 
mitted, that  every  animal,  the  size  and  texture 
of  which  admit  of  its  being  distinctly  ex- 
amined, is  possessed  of  sortie  organ  appro- 
priated to  the  purposes  of  digestion.f 

Of  the  three  orders  of  parts  mentioned 
above,  the  second  is  the  only  indispensable  one, 
or  that  which  is  alone  essential  to  the  due  per- 
formance of  the  function.  In  many  cases  the 
aliment  is  directly  received  into  the  stomach, 
without  any  previous  preparation,  either  che- 
mical or  mechanical,  and  there  are  not  a  few 
instances  in  which  the  residuary  matter  is  im- 
mediately rejected  from  the  stomach,  without 
any  distinct  apparatus  for  its  removal.    In  the 

*  Smith's  Introd.  to  Botany,  p.  5  ;  Grant,  Cyc. 
of  Anat.  v.  i.  p.  107.  Dr.  Willis,  on  the  other 
hand,  remarks,  in  the  same  work,  that  nothing 
resembling  a  stomach  has  been  found  in  any  vege- 
table, p.  107. 

t  Soemmering,  Corp.  hum.  fab.  t.  vi.  p.  229  ; 
Blumenbach's  Comp.  Anat.  §  82.  Many  of  the 
exceptions  which  were  supposed  to  exist  to  the 
general  rule  have  been  removed  by  the  interesting 
observations  of  Ehrenberg  ;  Ann.  Sc.  Nat.  t.  ii. 
2e  ser.;  Rogct's  Bridgewater  Treatise,  v.  ii.  p.  95. 


DIGESTION. 


following  pages  our  main  object  will  be  to  give 
an  account  of  the  function  of  digestion  as  it  is 
exercised  in  man  and  in  those  animals  which 
the  most  nearly  resemble  him,  referring  to 
other  animals  only  so  far  as  it  may  contribute 
to  illustrate  or  explain  the  nature  of  the  ope- 
ration in  the  human  species. 

In  the  various  divisions  of  the  Mammalia 
the  first  order  of  parts  may  be  arranged  under 
the  five  heads  of  the  mouth  with  its  muscular 
appendages,  the  teeth,  the  salivary  glands, 
the  pharynx,  and  the  oesophagus.  With  the 
exception  of  the  salivary  glands,  the  effect 
of  these  organs  is  entirely  mechanical ;  it  con- 
sists in  the  prehension,  the  mastication,  and 
the  deglutition  of  the  aliment.  The  first  of 
these  organs  may  be  again  subdivided  into 
three  parts,  the  lips,  the  cheeks,  and  the 
tongue ;  the  lips  being  more  immediately 
adapted  for  seizing  and  retaining  the  food, 
and  the  others  for  conveying  it,  in  the  first 
instance,  to  the  teeth,  for  the  purpose  of  mas- 
tication, and  afterwards  to  the  pharynx,  in 
order  that  it  may  be  swallowed.  In  this,  as 
in  every  other  part  of  the  animal  frame,  we 
perceive  that  adaptation  of  the  structure  of 
each  individual  organ  to  the  general  habits  of 
the  animal,  which  forms  a  constant  subject  of 
delight  and  admiration  to  the  anatomist  and 
the  physiologist.  In  animals  that  feed  upon 
succulent  and  luxuriant  herbage  the  lips  are 
capacious,  strong,  and  pendulous,  for  the  pur- 
pose of  grasping  and  detaching  their  food, 
while  in  those  that  employ  an  animal  diet, 
where  their  prey  is  to  be  seized  and  divided 
principally  by  means  of  the  teeth,  the  lips  are 
thin,  membranous,  and  retractile.  Again  in 
the  muscles  that  are  connected  with  the  cheeks, 
we  find  the  same  adaptation,  although  perhaps 
not  in  so  obvious  a  degree.  We  observe  that 
animals  who  receive  large  quantities  of  food, 
either  in  consequence  of  its  being  of  a  less 
nutritive  nature,  or  from  any  other  peculiarity 
in  their  habits  and  organization,  as  well  as 
those  whose  food  is  of  a  harder  consistence 
and  firmer  texture,  have  larger  and  more 
powerful  muscles,  both  for  the  purpose  of 
moving  the  jaws  with  greater  force,  and  for 
acting  upon  the  larger  mass  of  matter  which  is 
taken  into  the  mouth. 

The  principle  of  adaptation  is  still  more 
remarkable  in  the  teeth.  Among  the  different 
orders  which  compose  the  Mammalia,  we  ob- 
serve a  general  analogy  and  resemblance  be- 
tween the  teeth,  both  as  to  their  number,  form, 
and  relative  position,  while,  at  the  same  time, 
there  is  so  great  a  diversity  in  the  different 
tribes  of  animals,  that  some  of  the  most  dis- 
tinguished naturalists  have  regarded  these 
organs  as  the  parts  the  best  adapted  for  form- 
ing the  basis  of  their  systematic  arrangements, 
inasmuch  as  they  afford  the  most  characteristic 
marks  of  the  habits  of  the  animals,  and  of  the 
peculiarities  of  their  other  functions.*  Thus, 
by  an  inspection  of  the  teeth  we  can  at  once 
discover  whether  the  individual  is  intended  to 

*  Linnasus,   Sys.  Nat.  t.  i.  p.  16  et  alibi  ; 
Shaw's  Zool,  v.  i.  Intioil.  p.  vii  et  alibi. 


employ  animal  or  vegetable  food,  some  of  them 
being  obviously  adapted  for  seizing  and  lace- 
rating the  animals  which  they  acquire  in  the 
chace  or  by  combat,  while  the  teeth  of  others 
are  obviously  formed  for  the  cropping  of  vege- 
tables, and  for  breaking  down  and  triturating 
the  tough  and  rigid  parts  of  which  they  prin- 
cipally consist.  It  is  with  a  view  to  this  dou- 
ble purpose  of  prehension  and  mastication  that 
the  great  division  of  the  teeth  into  the  incisors 
and  the  molares,  the  cutting  and  the  grinding 
teeth,  depends,  the  former  being  of  course 
situated  in  the  front  of  the  mouth,  the  latter 
in  the  sides  of  the  jaws.  The  chemical  com- 
position and  mechanical  texture  of  the  teeth  is 
no  less  adapted  to  their  office  of  dividing  and 
comminuting  the  food  than  their  figure  and 
position.  They  are  composed  of  nearly  the 
same  materials  with  the  bones  generally,  but 
their  texture  is  considerably  more  dense  and 
compact,  while  they  are  covered  with  an  ena- 
mel of  so  peculiarly  firm  a  consistence,  as  to 
enable  them,  in  many  kinds  of  animals,  to 
break  down  and  pulverize  even  the  hardest 
bones  of  other  animals,  and  to  reduce  them  to 
a  state  in  which  they  may  be  swallowed,  and 
received  by  the  stomach,  in  the  condition  the 
best  adapted  for  being  acted  upon  by  the  gastric 
juice.* 

At  the  same  time  that  the  alimentary  matter 
is  subjected  to  the  mechanical  action  of  the 
teeth,  it  is  mixed  with  the  fluids  that  are  dis- 
charged from  the  salivary  and  mucous  glands, 
which  are  situated  in  various  parts  of  the 
mouth.  The  use  of  the  saliva  is  to  soften  the 
food,  and  thus  render  it  more  easily  masti- 
cated, to  facilitate  its  passage  along  the  pha- 
rynx and  oesophagus,  and  perhaps,  by  a  certain 
chemical  action,  to  prepare  it  for  the  change 
which  it  is  afterwards  to  experience,  when  it  is 
received  into  the  stomach  .f 

The  food,  after  it  has  been  sufficiently  di- 
vided by  the  teeth,  and  incorporated  with  the 
saliva,  is  transmitted,  by  the  act  of  deglutition, 
into  the  stomach.  There  is  perhaps  no  part 
of  the  system,  which  exhibits  a  more  perfect 
specimen  of  animal  mechanism  than  the  pro- 
cess of  deglutition.  It  consists  in  the  succes- 
sive contraction  of  various  muscles,  lhat  are 
connected  with  the  contiguous  parts,  each  of 
which  contributes  to  form  a  series  of  mecha- 
nical actions,  which,  when  connected  with 
each  other,  effect  the  ultimate  object  in  the 
most  complete  manner.  The  muscles  of  the 
mouth  and  the  tongue  first  mould  the  mas- 
ticated aliment  into  the  proper  form,  and  trans- 
mit it  to  the  pharynx ;  this  part  is,  at  the  same 
time,  by  the  cooperation  of  other  muscles, 
placed  in  the  most  suitable  position  for  re- 
ceiving the  alimentary  mass,  and  transmitting 
it  to  the  oesophagus,  while  another  set  of  mus- 

*  Hatchett,  in  Phil.  Trans,  for  1799,  p.  328-9 ; 
Berzelius,  View  of  Animal  Chemistry,  p.  78 ; 
Pepys,  in  Fox  on  the  Teeth,  p.  92  et  seq  ;  Turner's 
Chemistry,  p.  1012. 

t  For  the  opinions  that  were  entertained  by  the 
older  physiologists  on  this  point  the  reader  is  re- 
ferred to  Baglivi,  Diss.  2,  circa  salivam,  op. 
p.  412  et  seq.;  also  to  Haller,  El.  Phys.  18.  2.  13. 


DIGESTION. 


9 


cles  causes  the  epiglottis  to  close  the  passage 
into  the  larynx.  The  muscular  fibres  of  the 
oesophagus  itself  are  now  brought  into  play, 
and  by  their  successive  contraction,  propel  the 
food  from  the  upper  to  the  lower  part  of  the 
tube,  and  thus  convey  it  to  its  final  destination. 
These  three  stages,  which  altogether  constitute 
.a  very  complicated  train  of  actions,  are  so 
connected  with  each  other,  that  the  operation 
appears  to  be  of  the  most  simple  kind;  it  is 
one  of  the  first  that  is  performed  by  the  newly 
born  animal,  and  is  exercised  during  the  whole 
period  of  existence  with  the  most  perfect 
facility.* 

The  food,  after  having  thus  experienced  the 
action  of  the  first  order  of  parts,  which,  as  we 
have  seen  above,  is  principally,  if  not  entirely, 
of  a  mechanical  nature,  is  finally  deposited  in 
the  stomach.  The  stomach  is  a  bag  of  an 
irregular  oval  form,  which  lies  obliquely  across 
the  upper  part  of  the  abdomen,  in  what  is 
termed,  from  the  presence  of  this  organ,  the 
epigastric  region.  The  structure  of  the  sto- 
mach, considered  in  its  physiological  relation, 
is  threefold.  A  large  portion  of  it  is  composed 
of  membranous  matter,  which  gives  it  its  ge- 
neral form,  determines  its  bulk,  and  connects 
it  with  the  neighbouring  parts,  constituting  its 
external  coat.  To  the  interior  surface  of  this 
coat  are  attached  a  number  of  muscular  fibres, 
by  which  the  various  contractile  actions  of  the 
stomach  are  performed;  these,  although  not 
capable  of  being  exhibited  as  a  connected  or 
continuous  structure,  are  considered,  accord- 
ing to  the  custom  of  the  anatomists,  as  com- 
posing the  muscular  coat,  while  its  internal 
coat  consists  of  a  mucous  membrane,  which 
appears  to  be  the  immediate  seat  of  the  se- 
creting glands,  from  which  the  stomach  de- 
rives its  appropriate  fluids.  But  besides  this, 
which  may  be  regarded  as  the  physiological 
structure  of  the  stomach,  by  which  its  parts 
are  so  arranged  as  to  give  the  organ  its  form 
and  position,  its  contractile  power,  and  its 
chemical  action,  the  anatomists  have  resolved  it 
into  a  greater  number  of  mechanical  divisions, 
depending  principally  upon  the  minuteness  to 
which  they  have  carried  their  dissections.  In 
this  way  no  less  than  six  or  even  eight  distinct 
strata  or  coats  have  been  assigned  to  the  sto- 
mach. First,  the  peritoneal  covering,  which  it 
has  in  common  with  all  the  other  abdominal 
viscera,  the  dense  membrane  which  more 
especially  gives  the  stomach  its  form,  called 
in  the  language  of  the  older  writers  the  ner- 
vous coat,  two  muscular  coats,f  one  composed 
of  longitudinal  and  the  other  of  circular  fibres, 
and  the  innermost,  or,  as  it  has  been  termed, 

*  For  a  minute  account  of  the  process  of  deglu- 
tition generally  we  may  refer  to  Boerhaave,  Praol. 
t.  i.  §  70.  .2,  Hallcr's  Phys.  by  Mihles,  lect.  23; 
Prim.  Lin.  cap.  18,  <f  607  .  .  621  ;  El.  Phys.  xviii. 
3.  21.  .5;  Dumas,  Physiol,  t.  i.  p.  341.  .  353,  who 
divides  the  act  of  deglutition  into  four  stages,  and 
to  Magendie,  Physiol,  t.  ii.  p.  54..  67,  who  reduces 
them  to  three. 

f  Boyer,  ubi  supra,  supposes  that  the  muscular 
fibres  are  arranged  in  three  layers.  See  also  El- 
liotsou's  Physiol,  p.  78. 


the  villous  coat,  together  with  three  cellular 
coats,  which  are  situated  between  the  former 
and  connect  them  with  each  other.  The  ner- 
vous coat  is  usually  described  as  being  the  seat 
of  the  glands,  as  well  as  of  the  bloodvessels, 
nerves,  and  absorbents  which  belong  to  the 
stomach;  but  although  they  cannot  perhaps 
be  actually  traced  beyond  this  part,  there  is 
some  reason  to  suppose  that  their  ultimate 
destination  is  on  the  innermost  or  villous 
coat. 

The  membranous  part  of  the  stomach  ap- 
pears to  be  peculiarly  distensible,  so  as  readily 
to  admit  of  having  its  capacity  greatly  and 
suddenly  increased,  in  order  to  contain  the 
large  quantity  of  solids  and  fluids  that  are 
occasionally  received  into  it,  while  its  mus- 
cular fibres  and  nerves  are  possessed  respec- 
tively of  a  high  degree  of  contractility  and 
sensibility,  by  which  they  act  powerfully  on 
its  contents,  propelling  them,  when  necessary, 
into  the  duodenum,  and  thus  reducing  the 
bulk  of  the  stomach  to  its  ordinary  standard. 
Besides  the  mucous  fluid  which  the  inner  sur- 
face secretes,  in  common  with  all  other  mem- 
branes of  this  description,  the  stomach  is  sup- 
posed to  possess  certain  glands,  adapted  for 
the  formation  of  a  specific  fluid,  termed  the 
gastric  juice,  which  acts  an  important  part  in 
the  process  of  digestion  ;  but  the  presence  of 
these  glands  has  been  rather  inferred  from  then- 
supposed  necessity,  than  from  any  actual  ob- 
servation of  their  existence.* 

From  the  peculiar  form  and  disposition  of 
what  have  been  termed  the  muscular  coats  of 
the  stomach,  they  not  only  enable  the  organ 
to  contract  in  its  whole  extent  and  in  all  direc- 
tions, but  they  give  to  its  individual  parts  the 
power  of  successively  contracting  and  relaxing, 
so  as  to  produce  what  has  been  termed  its 
peristaltic  or  vermicular  motion  .f  The  effect 
produced  appears  to  be,  in  the  first  instance, 
to  form  in  the  interior  of  the  stomach  a  series 
of  folds  or  furrows,  and  at  the  same  time  to 
agitate  the  alimentary  mass,  so  as  to  bring 
every  part  of  it,  in  its  turn,  within  the  in- 
fluence of  the  gastric  juice,  while  the  whole 
of  the  mass  is  gradually  carried  forwards  to- 
wards the  pylorus,  and  is  in  due  time  dis- 
charged from  that  orifice.  The  muscular  fibres 
of  the  stomach,  like  all  those  that  are  con- 
nected with  membranous  expansions,  forming 
what  are  termed  muscular  coats,  are  not  under 
the  control  of  the  will. 

In  consequence  of  the  great  degree  of  vitality 
which  the  stomach  possesses,  a  circumstance  in 
which  it  is  surpassed  by  scarcely  any  organ  in 
the  whole  body,  it  is  very  plentifully  provided 
with  bloodvessels  and  with  nerves.  The  arteries, 
according  to  the  ordinary  construction  of  the  sys- 
tem, are  furnished  by  the  contiguous  large  trunks, 


*  Winslow's  Anat.  Sect.  viii.  §  63..5  •,  Haller,  El. 
Phys.  xix.  1.  14;  Bell's  Anat.  v".  iv.  p.  58. 

t  Haller,  El.  Phys.  xix.  4.  9,0;  Boycr,  Anat. 
t.  iv.  p.  333  .  .  5  ;  Benin,  Mem.  Acad,  "pour  1760, 
p.  58  et  seq.;  this  writer  appears  to  have  been  one 
of  the  first  who  gave  us  a  correct  description  of  fie 
muscular  coats  of  the  stomach. 


10 


DIGESTION. 


while  the  veins,  in  common  with  all  those  that  be- 
long to  what  are  termed  the  chylopoietic  viscera, 
terminate  in  the  vena  portae.*  The  nerves  of  the 
stomach  are  not  only  very  numerous,  but  they 
are  remarkable  for  the  number  of  different 
sources  whence  they  derive  their  origin.  These 
are,  in  the  first  instance,  threefold  ;  it  is  fur- 
nished with  a  large  quantity  of  ganglionic 
nerves,  in  common  with  all  the  neighbouring 
viscera ;  it  likewise  receives  nerves  directly 
from  the  spinal  cord,  and  unlike  all  the  other 
parts  of  the  body,  except  what  are  termed  the 
organs  of  sense,  it  has  a  pair  of  cerebral  nerves 
in  a  great  degree  appropriated  to  it.  The 
specific  uses  of  these  different  nerves  are  not 
certainly  ascertained,  and  it  would  scarcely  fall 
under  the  immediate  object  of  this  treatise  to 
enter  upon  the  consideration  of  this  point ;  but 
we  may  observe,  that  no  organ,  in  any  part  of 
the  body,  partakes  more  fully  of  what  may  be 
considered  as  the  actions  of  the  nervous  system, 
or  is  more  remarkably  affected  by  its  various 
changes,  including  not  merely  those  of  a  physio- 
logical nature,  but  such  likewise  as  are  con- 
nected with  the  various  mental  impressions.f 

The  two  extremities  of  the  stomach,  by  which 
the  food  is  received  and  discharged,  are  respec- 
tively termed  the  cardia  and  the  pylorus.  Their 
structure,  in  many  respects,  differs  from  that 
of  the  other  parts  of  the  organ.  The  cardia  is 
remarkable  for  the  great  proportion  of  nerves 
which  are  distributed  over  it,  and  as  these  are 
principally  derived  from  the  par  vagum,  or  the 
eighth  pair  of  cerebral  nerves,  we  may  under- 
stand why  this  should  be  the  most  sensitive 
part  of  the  stomach.  The  pyloius  is  remarkable 
for  the  mechanical  disposition  of  its  muscular 
fibres,  which  form  an  imperfect  kind  of  sphinc- 
ter, by  which  the  food  is  detained  in  the  cavity 
until  it  has  experienced  the  chemical  action  of 
the  gastric  juice.  And  besides  the  functions 
which  are  actually  possessed  by  this  part,  many 
imaginary  and  mysterious  powers  were  ascribed 
to  the  pylorus  by  the  older  physiologists.  The 
sensibility  of  the  stomach  was  supposed  to 
reside  more  especially  in  this  extremity  ;  it  was 
selected  by  some  of  the  visionary  philosophers 
of  the  sixteenth  and  seventeenth  centuries  as 
being  the  seat  of  the  soul,  and  even  some  of  the 
moderns  ascribe  to  it  a  kind  of  intelligence  or 
peculiar  tact,  by  which  it  is  enabled  to  select  the 
part  of  the  alimentary  mass,  which  has  been 
sufficiently  prepared  to  enter  the  duodenum, 
while  it  prevents  the  remainder  from  passing 
through  its  orifice,  and  retains  it  for  the  purpose 
of  being  still  farther  elaborated.]: 

On  account  of  the  form  and  position  of  the 
stomach  it  is  sufficiently  obvious,  that  a  con- 
siderable proportion  of  its  contents  must  be,  at 
all  times,  below  the  level  of  the  pylorus.  The 
food  is  hence  prevented  from  passing  too  hastily 
out  of  the  organ,  while  we  may  conclude  that 

*  Winslow,  sect.  viii.  §  2.  72.  .7  ;  Haller,  El. 
Phys.  xix.  ).  16.  .20 ;  Blumenbach,  Jnst.  Physiol. 
§  356  ;  Bell's  Dissect,  p.  19  .  .  25.  pi.  3,  4. 

t  Winslow,  ubi  supra,  78,  9 ;  Haller,  xix.  1.  21  ; 
Blumenbach,  §  355;  Bell's  Anat.  v.  iv.  p.  64; 
Walter,  Tab.  nerv.  No.  3,  4. 

i  Richcrand,  Physiol.  §23.  §  111,  2. 


the  transmission  of  the  food  is  almost  entirely 
effected  by  the  contraction  of  its  muscular 
fibres,  aided  probably  by  the  diaphragm  and 
the  abdominal  muscles,  but  scarcely  in  any 
degree  by  the  mere  action  of  gravity.*  It  must, 
however,  be  observed  that  the  position  of  the 
stomach  generally,  with  respect  to  the  neighbour- 
ing organs,  as  well  as  the  relation  of  its  different 
parts  to  each  other,  varies  considerablyaccording 
to  its  state  of  repletion  ;  when  it  is  the  most  fully 
distended,  its  large  arch,  which  previously  was 
pendulous,  is  now  pushed  forwards  and  raised 
upwards,  so  as  to  be  nearly  on  the  same  level 
with  the  pylorus.f 

When  the  food  leaves  the  stomach,  it  is  re- 
ceived by  the  intestinal  canal,  a  long  and 
winding  tube,  which  varies  much  in  its  diameter 
and  its  form,  in  the  different  parts  of  its  course, 
but  which,  both  in  its  anatomical  structure  and 
in  its  physiological  functions,  bears  a  consider- 
able resemblance  to  the  stomach.  It  may  be 
said,  in  the  same  manner,  to  consist  of  three 
essential  parts,  the  membranous,  the  muscular, 
and  the  mucous,  which  respectively  serve  to 
give  it  its  form,  to  enable  it  to  propel  its  con- 
tents, and  to  furnish  the  necessary  secretions. 
With  respect  to  the  form  of  its  individual  parts, 
it  has  been  divided,  in  the  first  instance,  into 
the  large  and  small  intestines,  a  division  which 
depends  upon  the  comparative  diameter  of  the 
two  portions,  while  each  of  these  has  been  sub- 
divided into  three  parts,  depending  more  upon 
their  form  and  their  position  than  upon  their 
structure  or  functions. 

But  although  it  may  be  supposed,  that  the 
division  of  the  tube  into  the  great  and  small  in- 
testines refers  to  their  difference  of  size  alone,  it 
is  to  be  observed  that  they  perform  very  differ- 
ent functions,  and  are  subservient  to  very  differ- 
ent purposes  in  the  animal  ceconomy.  It  is  in 
the  small  intestines,  and  more  especially  in  the 
first  portion  of  them,  termed  the  duodenum, 
that  what  must  be  considered  as  the  most  essen- 
tial or  specific  part  of  the  function  of  digestion 
is  effected,  the  formation  of  chyle,  while  it  is 
almost  exclusively  in  the  duodenum  and  the 
other  small  intestines,  the  jejunum  and  the 
ileum,  that  the  chyle  thus  produced  is  taken  up 
by  the  lacteals,  in  order  to  be  conveyed  to 
the  thoracic  duct,  and  finally  deposited  in  the 
bloodvessels. 

The  use  of  the  large  intestines,  and  more  es- 
pecially of  the  colon,  which  constitutes  a  con- 
siderable proportion  of  the  whole,  appears  to  be 
more  of  a  mechanical  nature,  serving  as  a  depo- 
sit or  reservoir,  in  which  the  residuary  matter 
is  received  and  lodged,  for  a  certain  period,  until 
it  is  finally  expelled  from  the  system.  The 
division  between  the  parts  of  the  small  intestines, 
to  which  the  names  jejunum  and  ileum  have 
been  applied,  is  entirely  arbitrary,  as  they  ap- 
pear to  be  precisely  similar  to  each  other,  both 
in  their  structure  and  their  functions.  But  the 
case  is  very  different  with  respect  to  the  duode- 
num, which  in  both  these  respects  possesses  a 
clearly  marked  and  distinctive  character.  Of 

*  Haller,  ubi  supra,  §2.  .4. 
t  Blumenbach,  §  353. 


DIGESTION. 


11 


this  anatomists  have  long  been  well  aware,  and 
it  has  accordingly  been  made  the  object  of  par- 
ticular attention,  and  has  even  received  the  ap- 
pellation of  the  accessory  stomach ;  but  we  shall 
enter  more  particularly  into  the  consideration  of 
this  subject  when  we  come  to  treat  upon  the 
difference  between  chyme  and  chyle,  and  the 
nature  of  the  process  by  which  it  is  effected. 

The  peculiarities  of  the  digestive  organs  in 
the  different  classes  of  animals  are  interesting, 
not  merely  as  affording  remarkable  examples  of 
the  adaptation  of  the  animal  to  the  situation  in 
which  it  is  placed,  but  are  especially  worthy  of 
our  notice  on  this  occasion,  as  serving  to  illus- 
trate the  nature  of  the  operation  generally,  and 
the  mode  in  which  its  various  stages  are  related 
to  each  other.  The  most  remarkable  examples 
of  this  kind  are  the  complicated  stomachs  of  the 
ruminant  quadrupeds,  and  the  muscular  sto- 
machs of  certain  classes  of  birds.* 

The  ruminant  animals  belong  to  the  class  of 
the  mammalia,  and  are  such  as  feed  principally 
upon  the  stalks  and  leaves  of  plants.  The  quan- 
tity of  food  which  they  take  is  very  consider- 
able ;  it  is  swallowed,  in  the  first  instance,  al- 
most without  mastication,  and  is  received  into 
the  first  stomach,  a  large  cavity,  which  is  termed 
the  venter  magnus,  pause,  or  paunch.\  The 
food,  after  remaining  for  some  time  in  this  sto- 
mach, for  the  purpose,  as  it  would  appear,  of 
being  macerated,  is  next  conveyed  into  the 
second  stomach,  a  smaller  cavity,  the  internal 
coat  of  which  is  drawn  up  into  folds  that  lie  in 
both  directions,  so  as  to  form  a  number  of  an- 
gular cells,  from  which  circumstance  it  has 
received  the  appellation  of  reticulum,  bonnet, 
or  honeycomb.  The  reticulum  is  provided 
with  a  number  of  strong  muscular  fibres,  by 
which  the  food  is  rounded  into  the  form  of  a 
ball,  and  is  propelled  along  the  oesophagus  into 
the  mouth.  It  is  now  completely  masticated, 
after  having  been  properly  prepared  for  the  pro- 
cess by  its  previous  maceration  in  the  paunch  ; 
this  mastication  constitutes  what  has  been 
termed  chewing  the  cud,  or  rumination. 

When  the  food  has  been  sufficiently  com- 
minuted it  is  again  swallowed,  but  by  a  pecu- 
liar mechanism  of  muscular  contraction  the 
passage  into  the  venter  magnus  is  closed,  while 
an  opening  is  left  for  it  to  pass  into  the  third 
stomach,  termed  omasum,  feui  I  let,  or  muniplies  ; 
it  is  smaller  than  any  of  the  other  cavities,  and 
its  internal  coat  is  formed  into  a  series  of  strong 
ridges  and  furrows,  but  without  the  transverse 
ridges  of  the  reticulum.  From  the  omasum  the 
food  is  finally  deposited  in  the  fourth  stomach, 
the  abomasum,  caillette,  or  reed,  a  cavity  consi- 
derably larger  than  either  the  second  or  third 
stomach,  although  less  than  the  first.  It  is  of 
an  irregular  conical  form,  the  base  being  turned 

*  For  an  interesting  account  of  the  comparative 
anatomy  of  the  digestive  organs  we  may  refer  to 
Carus's  Comparative  Anatomy,  by  Gore,  v.  ii.  p.  72 
et  seq. 

t  We  have  selected  the  terms  by  which  each  of 
the  four  stomachs  is  usually  designated  in  Latin, 
French,  and  English  respectively;  there  are,  how- 
ever, various  other  names  which  have  been  applied 
to  them. 


to  the  omasum  ;  it  is  lined  with  a  thick  mucous 
or  villous  coat,  which  is  contracted  into  ridges 
or  furrows,  somewhat  in  the  manner  of  the  oma- 
sum, and  it  appears  to  be  that  part  of  the  diges- 
tive apparatus  which  is  analogous  to  the  single 
stomach  of  the  other  mammalia,  where  the  ali- 
ment undergoes  the  process  of  chymification,  the 
three  first  stomachs  being  intended  to  macerate 
and  grind  it  down,  in  order  to  prepare  it  for  the 
action  of  the  gastric  juice.   (See  Ruminantia.) 

Although  we  conceive  that  the  operation  of 
the  different  parts  of  this  complicated  apparatus 
is  pretty  well  understood,  it  still  remains  for  us 
to  inquire  into  the  final  cause  of  the  arrange- 
ment, or  why  the  maceration  and  mastication  of 
the  food  in  certain  classes  of  animals  should  be 
effected  in  a  manner  so  different  from  what  it  is 
in  others,  which,  in  their  general  structure  and 
functions,  the  most  nearly  resemble  them.  The 
opinion  which  was  entertained  on  this  subject 
by  the  older  anatomists,  and  which  may  be  still 
regarded  as  the  popular  doctrine,  is,  that  the 
nature  of  the  food  of  these  animals,  and  the  large 
quantity  of  it  necessary  for  their  support,  requires 
a  greater  length  of  time  for  its  comminution  and 
a  greater  quantity  of  the  mucous  secretions  than 
it  could  obtain  by  the  ordinary  process.  But 
although  there  may  be  some  foundation  for  this 
opinion,  the  more  extended  observations  of 
modern  naturalists  show,  that  it  does  not  apply 
in  all  cases,  and  that  there  are  so  many  excep- 
tions to  the  general  rule  as  to  lead  us  to  doubt 
the  truth  of  the  position.*    It  is  to  be  ob- 
served, that  when  animals  with  ruminant  sto- 
machs take  in  liquids,  the  fluid  passes  immedi- 
ately into  the  second  stomach,f  where  it  is 
mixed  with  the   aliment  after  it  has  been 
macerated  in  the  venter  magnus,  and  probably 
moulds  it  into  the  proper  form,  for  its  return 
along  the  oesophagus  into  the  mouth.  While 
the  young  animal  is  nourished  by  the  mother's 
milk,  the  fluid  is  conveyed,  in  the  first  instance, 
through  the  third  stomach  into  the  fourth,  and  it 
is  not  until  it  begins  to  take  solid  food,  that  the 
process  of  rumination  is  established.     It  is 
hence  concluded,  that  the  animal  possesses  the 
power  of  conveying  the  food  at  pleasure  either 
into  the  first  or  the  third  stomach,  and  of  return- 
ing it  from  the  second  into  the  mouth  ;|  these, 
like  many  other  voluntary  acts,  being  of  the 
kind  which  are  termed  instinctive. 

The  other  kind  of  stomach  which  we  referred 
to  above  as  possessing  a  peculiar  structure, 
and  acting  on  a  different  principle  from  that  of 
the  human  species,  is  the  muscular  stomach  of 
certain  classes  of  birds.  Birds  are  not  pro~ 
vided  with  teeth,  or  with  any  apparatus  which 
can  directly  serve  for  the  process  of  mastica- 
tion; yet  many  of  them  feed  upon  hard  sub- 
stances, which  cannot  be  acted  upon  by  the 
gastric  juice,  until  they  have  undergone  some 
process,  by  which  they  may  be  comminuted  or 
ground  down  into  a  pulpy  mass.  This  is 
effected  by  the  ingluvies,  the  craw  or  crop,  and 
the  ventricuius  bnlbosus  or  gizzard.    The  first 

*  Blumenbach's  Comp.  Anat.  p.  138.  note  20. 
t  Home,  ubi  supra,  p.  363. 

\  Blumcnbach,  uhi  supra,  p.  138.  note  18;  Ray's 
Wisdom  of  God,  &c,  p.  188. 


12 


DIGESTION. 


of  these  is  a  large  membranous  bag,  analogous 
to  the  paunch  of  the  ruminants,  into  which  the 
food,  without  any  previous  alteration,  is  re- 
ceived from  the  oesophagus,  and  where  it  is 
macerated  in  the  usual  manner  by  the  conjoined 
action  of  heat  and  moisture. 

The  gizzard  is  of  much  smaller  dimensions 
than  the  crop,  composed  of  four  muscles,  two 
of  which  are  of  a  flattened  form  and  of  very 
dense  texture,  lined  internally  with  a  firm  cal- 
lous membrane,  and  capable  of  an  extremely 
powerful  action.    These  constitute  the  main 
part  of  the  parietes,  the  two  other  muscles  being 
much  smaller,  and  situated  at  the  extremities, 
serving,  as  it  would  appear,  merely  to  com- 
plete the  cavity.*    The  gizzard  is  so  connected 
with  the  crop,  that  the  food,  after  due  macera- 
tion, is  allowed  to  pass  by  small  successive 
portions  between  the  two  larger  muscles ;  by 
their  contraction  they  are  moved  laterally  and 
obliquely  upon  each  other,  so  that  whatever  is 
placed  between  them  is  completely  triturated. 
The  force  of  these  muscles,  as  well  as  the 
impenetrability  of  their  investing  membrane,  is 
almost  inconceivably  great,  so  that,  according 
to  the  experiments  of  Spallanzani  and  others, 
not  only  are  the  hardest  kinds  of  seeds  and 
grains  reduced  to  a  perfect  pulp,  but  even 
pieces  of  glass,  sharp  metallic  instruments, 
and  mineral  substances,  are  broken  down  or 
flattened,  while  the  part  still  remains  unin- 
jured.f    The  action  of  both  the  crop  and  the 
gizzard  must  be  regarded  as  at  least  essentially 
mechanical,  mainly  adapted  for  the  purposes 
of  maceration  and  trituration,  and  as  compen- 
sating for  the  saliva  and  teeth  of  man  and  the 
greatest  part  of  the  mammalia.    We  are  able 
in  this  case  to  observe  the  connexion  between 
the  habits  of  the  animals  and  the  peculiarities 
of  their  organs  more  clearly  than  with  regard 
to  the  ruminants,  for  we  can  always  perceive 
an  intimate  relation  between  the  food  of  the 
different  kinds  of  birds  and  the  structure  of 
their  stomach. 

II.  An  account  of  the  nature  of  the  substances 
usually  employed  as  food. — All  the  articles  that 
are  employed  in  diet  may  be  arranged  under 
the  two  primary  divisions  of  animal  and  vege- 
table, according  to  the  source  whence  they  are 
derived.  Those  in  which  the  distinctive  cha- 
racters are  the  most  strongly  marked  differ  both 
in  their  proximate  principles  and  their  ultimate 
elements,  although  in  this,  as  in  most  other  cases, 
there  are  many  intermediate  shades.  The  ulti- 
mate elements  of  vegetables  are  oxygen,  hy- 
drogen, and  carbon,  to  which,  in  some  cases, 
a  portion  of  nitrogen  is  added.  Animal  sub- 
stances contain  all  these  four  ingredients,  the 
carbon  being  in  less  quantity  than  in  vege- 

*  Grew,  ubi  supra,  p.  34 ;  Bluinenbach,  ubi 
supra,  §99;  Pcjer,  Anat.  Ventr.  Gall.,  in  Man- 
get,  Bibl.  Anat.  t.  i.  p.  172;  Hunter  on  the  Ani- 
mal G3conomy,  p.  198-9;  C'lift,  in  Phil.  Trans,  for 
1807,  pi.  5,  fig.  1  ;  Home's  Lect.  v.  ii.  pi.  49,  62  ; 
and  the  ait.  Avp.s. 

t  Spallanzani,  Dissert,  i.  §  5  . .  8,  and  10 .  .  22  ; 
see  also  Acad,  del  Cimento,  p.  268,9  ;  Borelli,  De 
motu  anim.  t.  ii.  prop.  189 ;  Redi,  Esperiense,  p.  89 
et  seq.  ;  Grew,  ch.  8  ;  the  art.  "  Birds"  in  Rees  ; 
and  "  Aves"  by  Air.  Owen,  in  the  present  work- 


tables,  while  the  hydrogen,  and  still  more  the 
nitrogen,  are  generally  in  much  greater  quan- 
tity. There  are  various  circumstances  which 
seem  to  prove  that  either  species  of  diet  is 
alone  competent  to  the  support  of  life,  although 
each  of  them  is  more  especially  adapted  to 
certain  classes  of  animals.  This,  it  is  pro- 
bable, depends  both  upon  the  chemical  and 
the  mechanical  nature  of  the  substances  in 
question,  but  perhaps  more  upon  the  latter 
than  the  former,  for  we  find  that  the  processes 
of  cookery,  which  act  principally  upon  mecha- 
nical principles,  render  various  substances  per- 
fectly digestible,  which  the  stomach  could  not 
act  upon  before  they  had  undergone  these 
operations.  We  also  find  that  animals,  which, 
in  their  natural  state,  have  the  strongest  in- 
stinctive predilection  for  certain  kinds  of  food, 
may,  by  a  gradual  training  and  the  necessary 
preparation  of  the  articles  employed,  have  their 
habits  entirely  changed,  without  their  health 
being  in  any  degree  affected. 

There  is,  however,  a  circumstance  in  the 
structure  of  the  animal,  which  clearly  points 
out  a  natural  provision  for  the  reception  of  one 
species  of  food  in  preference  to  the  other,  viz. 
the  comparative  capacity  of  the  digestive  or- 
gans. It  may  be  concluded  that,  in  all  cases, 
the  aliment  must  undergo  a  certain  change 
before  it  can  serve  for  the  purpose  of  nutrition, 
and  that  this  change  will  occupy  a  greater 
length  of  time,  and  that  a  greater  bulk  of 
materials  will  be  requisite,  according  as  the 
nature  of  the  food  received  into  the  stomach  is 
more  or  less  different  from  the  substance  into 
which  it  is  to  be  afterwards  reduced.  Hence, 
as  a  very  general  rule,  we  find  that  the  diges- 
tive organs  of  carnivorous  animals  are  less 
capacious  than  those  of  the  herbivorous,  and 
that  even  in  the  latter  there  is  a  considerable 
difference,  according  as  the  food  consists  of 
seeds  and  fruits  or  of  the  leaves  and  stems  of 
plants. 

There  are  indeed  certain  circumstances  in  the 
habits  of  some  of  the  carnivora  which  require 
organs  of  considerable  capacity,  as,  for  ex- 
ample, those  beasts  of  prey  who  take  their 
food  at  long  intervals,  being  supplied,  as  it 
were,  in  an  occasional  or  incidental  manner, 
so  that  it  becomes  necessary  for  them  to  lay  up 
a  considerable  store  of  materials,  and  to  take 
advantage  of  any  opportunity  which  presents 
itself  of  replenishing  the  stomach.  The  anato- 
mical structure  of  the  human  digestive  organs 
indicates  that  man  was  intended  by  nature  for 
a  mixed  diet  of  animal  and  vegetable  aliment, 
but  with  a  preponderance  towards  the  latter  ;* 
and  it  appears  in  fact  that,  while  a  suitable 
combination  of  the  two  seems  the  most  condu- 
cive to  his  health,  and  to  the  due  performance 
of  all  his  functions,  either  species  is  alone 
competent  to  his  growth  and  nutrition.f 

*  Cuvier,  Regne  Animal,  t.  i.  p.  86;  Lawrence's 
Lect.  p.  217  et  seq.  ;  see  also  the  elaborate  dis- 
sertation of  Richter,  De  victus  animalis  antiq.  &c. 

t  Haller,  El.  Phys.  xix.  3.  2  .  .  4  ;  these  sections 
contain  a  very  full  account  of  the  different  kinds  of 
diet  employed  by  different  nations  or  individuals. 
We  have  a  number  of  curious  facts  of  this  kind  in 


DIGESTION. 


18 


The  most  important  of  the  proximate  prin- 
ciples employed  in  diet  are  fibrin,  albumen, 
oil,  jelly,  gluten,  mucilage,  farina,  and  sugar, 
to  which  may  be  added  some  others  of  less 
frequent  occurrence.  They  are  derived,  more 
or  less,  from  almost  all  the  classes  of  animals 
and  vegetables,  and  from  nearly  all  their  indi- 
vidual parts,  their  employment  being  regulated, 
in  most  cases,  rather  by  the  facility  with  which 
they  are  procured,  and  reduced  into  a  form  proper 
to  be  acted  upon  by  the  stomach,  than  by  the 
quantity  of  nutritive  matter  which  they  con- 
tain. This  is  one  of  those  subjects  in  which 
we  have  to  notice  the  remarkable  effects  of 
habit  and  custom,  both  on  the  functions  and 
the  sensations.  We  find  whole  tribes  of  people 
living  on  a  diet,  which,  to  those  unaccustomed 
to  it,  would  be  not  only  in  the  highest  degree 
unpalatable,  but  likewise  altogether  indiges- 
tible ;  while,  by  the  various  modes  of  preparing 
food,  which  have  been  suggested,  either  by 
luxury  or  by  necessity,  the  most  intractable 
substances  are  reduced  into  a  digestible  state.* 
The  writers  on  dietetics  have  attempted  to 
include  all  substances  that  are  competent  to 
afford  nutrition  under  a  few  general  principles, 
of  which,  as  they  exist  in  nature,  they  are 
supposed  to  be  composed.  Cullen,  who  may 
be  considered  as  the  first  who  attempted  to  in- 
troduce correct  philosophical  principles  into 
this  department  of  physiology,  reduced  them 
to  two,  the  oily  and  the  saccharine,  and  endea- 
voured to  prove  that  all  the  animal  fluids  may 
be  referred  to  these  principles.!  Magendie, 
on  the  contrary,  proceeding  less  upon  their 
chemical  composition  than  upon  the  forms 
under  which  they  present  themselves,  classes 
alimentary  substances  under  the  nine  heads  of 
farinaceous,  mucilaginous,  saccharine,  acidu- 
lous, oily,  caseous,  gelatinous,  albuminous, 
and  fibrinous. J  Dr.  Prout,  whose  views  on 
this  subject  are  marked  by  his  characteristic 
acuteness,  reverts  to  the  mode  of  Cullen,  ad- 
mitting only  of  the  oily,  the  saccharine,  and 
the  albuminous  principles,  which  three,  he 
conceives,  form  the  "  groundwork  of  all  orga- 
nized bodies. "§ 

Of  animal  compounds  which  are  employed 


Stark's  works,  p.  94,  5;  see  also  Lorry,  Sur  les  ali- 
mens  ;  Plonk,  Bromatologia ;  Soemmering,  Corp. 
hum.  fab.  p.  241,  250 ;  Richerand,  El.  Phys.  §  3, 
p.  83  ;  Parr's  Diet.  art.  Aliment;  Pearson's  Syn- 
opsis, parti.  ;  Lawrence's  Lect.  p.  201,  9  ;  Thack- 
rah's  2d  Lect.  on  Diet,  p.  54  et  seq.  ;  Paris 
on  Diet  ;  Kogct's  Bridgewattr  Treatise,  part  2, 
ch.  3,  §  1. 

*  Elliotson's  Physiol,  p.  65,  6  ;  Rogct,  part  2, 
ch.  3,  §  1. 

t  Physiol.  $211,  and  Mat.  Med.  v.  i.  p.  1,  eh. 
1,  p.  218  et  seq. 

{  Physiol,  t.  ii.  p.  3,  4;  see  also  Fordyce  on  Di- 
gestion, p.  84  et  seq. ;  Paris  on  Diet,  part  2,  p. 
117  et  seq.  ;  Richerand,  El.  Physiol.  §  3,  p.  82; 
Dumas,  Physiol,  t.  i.  p.  187  ;  Davy's  Lect.  on  Agric. 
Chem.  p.  73  et  seq.  ;  Londe,  Diet,  de  Med.  et 
de  Chir.  art.  "  Aliment,"  t.  ii.  p.  1  et  seq;  Ros- 
tan,  Diet,  de  Med.  art.  "  Aliment,"  t.  i.  p.  523 
etseq.;  Rullier,  Ibid.  Art.  "Nutrition,"  t.  xv. 
p.  161  et  seq. ;  Kellie,  in  Brewster's  Encyc.  Art. 
"  A  liment." 

§  Abstract  of  his  Gulstonian  Lecture,  p.  5,  9. 


in  diet  milk  may  be  regarded  as  holding  the  first 
place,  both  from  its  nutritive  and  its  digestible 
properties,  and  as  such  it  has  no  doubt  been 
provided  by  nature  for  the  newly-born  animal, 
when  it  requires  a  diet,  which  may  be  adapted 
to  the  delicacy  of  its  organs  in  its  novel  state 
of  existence,  while,  at  the  same  time,  it  pro- 
vides for  its  rapid  growth.  We  accordingly 
find  that  the  three  principles  mentioned  above 
are  combined  in  milk  in  a  manner  the  most 
proper  for  this  double  purpose,  and  that  there 
is  no  compound,  either  natural  or  artificial, 
which  is  equally  well  suited  to  it.*  Next  to 
milk,  with  respect  to  its  nutritive  properties, 
we  may  class  eggs  of  various  kinds,  the  mus- 
cular fibre  of  animals,  and  their  gelatinous  and 
albuminous  parts,  very  few  of  which,  how- 
ever, are  employed  in  diet  until  they  have 
undergone  the  various  operations  of  cookery. 
Of  these  operations  the  most  important  in  their 
dietetical  effect  is  the  formation  of  decoctions 
or  infusions,  constituting  soups  of  all  descrip- 
tions, in  which  we  retain  the  more  soluble, 
and,  for  the  most  part,  the  more  nutritive  matter, 
while  the  residue  is  rejected.  The  fish  which 
are  usually  employed  in  diet  consist  of  a  much 
greater  proportion  of  jelly  and  albumen  than 
the  flesh  of  the  mammalia  and  of  birds ;  these 
principles  are  united,  in  most  cases,  with  a  con- 
siderable quantity  of  oil. 

The  most  nutritive  of  the  vegetable  proximate 
principles  is  gluten  ;  it  forms-  a  considerable 
proportion  of  certain  kinds  of  seeds,  and  more 
especially  of  wheat,  and  we  accordingly  find 
that  in  all  those  countries  which  admit  of  the 
growth  of  this  plant,  and  which  have  arrived 
at  any  considerable  degree  of  civilization, 
wheaten  bread  forms  the  most  important  article 
of  vegetable  diet,  and  one  which  appears  the 
best  adapted  for  all  ages  and  all  constitutions. 
Next  to  gluten  we  may  rank  farina,  both  from 
its  valuable  properties  and  from  the  extent  to 
which  it  is  employed.  It  enters  largely  into 
the  composition  of  wheat  and  of  the  other 
seeds  of  the  cerealia,  also  of  rice  and  maize, 
while  it  constitutes  a  great  proportion  of  the 
whole  substance  of  the  leguminous  seeds  and 
of  tubers.  It  also  forms  the  principal  in- 
gredient of  the  chesnut,  and  of  the  esculent 
alga?,  so  that,  upon  the  whole,  we  may  con- 
sider it  as  entering  more  largely  into  the  aliment 
of  mankind,  m  all  different  climates  and  situa- 
tions, than  any  other  vegetable  compound. 

Perhaps  there  is  no  proximate  principle 
which  contains  in  the  same  bulk  a  larger  pro- 
portion of  nutritive  matter  than  oil,  and  we 
accordingly  find  that  oil,  as  derived  either  from 
the  animal  or  vegetable  kingdom,  enters  largely 
into  the  diet  of  all  nations.  But  it  affords  an 
example  of  one  of  those  articles,  which,  al- 
though highly  nutritious,  is  not  very  digestible 
without  a  due  admixture  of  other  substances, 
which  may  in  some  way  render  it  more  proper 
for  the  action  of  the  gastric  juice  f    It  may 

*  Prout,  ut  supra,  p.  12. 

t  It  is  upon  this  principle,  rather  than  to  the  ab- 
sence of  azote,  that  we  should  be  disposed  to  account 
for  the  results  of  Magendie's  experiments,  in  which 


14 


DIGESTION. 


indeed  be  received  as  a  very  general  rule  that  a 
certain  quantity  of  matter,  which  in  itself 
contains  but  a  small  proportion  of  the  princi- 
ples which  immediately  serve  for  nutrition,  js 
necessary  for  the  due  performance  of  the  func- 
tions of  the  stomach,  probably  in  some  degree 
for  the  purpose  of  mere  dilution  or  mechanical 
division.  The  same  remark  applies  to  sugar 
as  to  oil.  Sugar  would  appear  to  be  one  of 
the  most  nutritive  of  the  proximate  principles, 
but  when  taken  alone  or  in  too  great  quantity 
it  deranges  the  digestive  organs,  and  becomes 
incapable  of  supporting  life.* 

The  difference  in  the  different  kinds  of  ali- 
ment between  their  capacity  of  affording,  the 
materials  from  which  chyme  may  be  produced, 
and  the  facility  with  which  they  are  acted  upon 
by  the  stomach,  or  in  ordinary  language,  be- 
tween their  nutritive  and  their  digestible  quality, 
has  been  distinctly  recognized  by  various  phy- 
siologists,t  although  it  has  not  always  been 
sufficiently  attended  to.  We  have  some  strik- 
ing illustrations  of  the  fact  in  a  series  of  expe- 
riments which  were  performed  by  Goss,J  and 
in  those  of  Stark,§  where  the  digestibility  and 
the  nutrition  of  various  species  of  aliment  bore 
no  relation  to  each  other,  while  they  afford  the 
most  decisive  proof  of  the  advantage,  or  rather 
the  necessity,  of  a  mixture  of  substances,  in 
order  to  produce  the  compound  which  is  the 
best  adapted  for  the  action  of  the  stomach. 

We  have  referred  above  to  the  difference  in 
the  digestive  powers  of  the  stomachs  of  diffe- 
rent classes  of  animals  as  depending  on  their 
peculiar  organization.  In  many  instances  the 
difference  is  so  strongly  marked  as  to  leave  no 
doubt  either  as  to  its  existence  or  as  to  the 
cause  by  which  it  is  directly  produced.  But 
there  are  many  cases  where  we  observe  the 
effect  without  being  able  to  assign  any  imme- 
diate cause  for  it ;  where  substances,  which  are 
highly  nutritive  and  perfectly  salutary  to  certain 
individuals,  are  apparently  incapable  of  being 
digested  by  others.  After  making  all  due  al- 
lowance for  the  effects  of  habit,  association, 
or  even  caprice,  there  still  appears  sufficient 
ground  for  concluding  that  there  are  original 
differences  in  the  powers  of  the  stomach,  which 
cannot  be  assigned  to  any  more  general  prin- 
ciple. This  observation  applies  principally  to 
the  individuals  of  the  human  species,  where 
such  variations,  or,  as  they  have  been  termed, 
idiosyncrasies,  of  all  descriptions  are  much 
more  apparent  than  in  any  other  kind  of  ani- 
mals. All  other  animals,  even  those  which 
the  most  nearly  resemble  the  human  species, 
are  much  more  uniform  in  this  respect,  being 
guided  in  the  choice  of  their  food  principally 
by  that  instinctive  feeling  which  leads  them 

he  found  that  animals  could  not  be  fed  upon  pure 
sugar,  oil,  or  gum-,  Physiol,  t.  ii.  p. 390,  and  Ann. 
Chim.  et  Phys.  t.  iii.  p.  66  et  seq.  ;  see  Bos- 
tock's  Physiol,  v.  ii.  p.  467,  8. 

*  Haller,  El.  Phys.  xix.  3.  12;  Stark's  Works, 
p.  94  et  alibi;  Pearson's  Synopsis,  p.  104,  5. 

t  Adelon  et  Chaussier,  Diet.  Sc.  Med.  Art. 
"  Digestion,"  t.  ix. 

t  Spallanzani,  Sur  la  Digestion,  par  Senebier, 
p.  cxxxi...cxl. 

§  Works,  p.  89  et  seq. 


to  select  the  substances  which  are  the  best 
adapted  for  their  organs.  But  even  here  we 
meet  with  ceitain  peculiarities,  where  animals 
prefer  certain  kinds  of  aliment,  and  where 
there  is  no  obvious  anatomical  or  physiological 
cause  which  can  explain  the  effect.  This, 
however,  we  may  regard  as  an  exception  to  the 
general  rule,  for  there  is  perhaps  no  one  of  the 
functions  in  which  we  are  enabled  more  clearly 
to  trace  the  adaptation  of  the  organ  to  the  struc- 
ture and  habits  of  the  animal,  than  in  what 
respects  the  supply  of  nutrition,  including  the 
mode  of  procuring  the  food,  and  the  whole  of 
the  series  of  changes  which  it  experiences  from 
the  digestive  organs.* 

Liquids  of  various  kinds  constitute  an  im- 
portant part  of  the  diet  of  almost  all  indivi- 
duals. They  may  be  arranged  under  the  two 
divisions  of  those  liquids  which  we  employ 
merely  for  the  purpose  of  quenching  thirst,  or 
diluting  our  solid  food,  or  such  as  are  made 
the  vehicles  of  nutriment,  including  various 
kinds  of  decoctions  and  infusions.  The  latter 
are  derived  both  from  the  animal  and  the  vege- 
table kingdoms,  and  when  duly  prepared  form 
a  species  of  food,  which,  as  containing  the 
most  soluble  and  the  most  sapid  portions,  is, 
in  most  cases,  both  highly  nutritive  and  diges- 
tible. But  we  observe  here  the  same  kind  of 
idiosyncrasy  to  which  we  referred  above,  and 
which  it  frequently  becomes  necessary  to  attend 
to  in  the  directions  that  are  given  respecting 
diet,  and  more  especially  to  invalids  and  to 
children. 

The  liquids  that  are  employed  for  the  pur- 
pose of  quenching  thirst,  which  are  more  pro- 
perly styled  drinks,  may  be  arranged  under  the 
two  heads  of  vegetable  infusions  or  decoctions 
and  fermented  liquors.  Of  the  former  a  great 
variety  have  been  employed  in  different  coun- 
tries and  at  different  periods,  but  in  Europe, 
almost  the  only  kinds  which  are  in  common 
use  are  tea  and  coffee.  These  cannot  be  con- 
sidered as  in  themselves  affording  any  nourish- 
ment, but  they  are  generally  employed  with  the 
addition  of  some  nutritive  substance,  and  if  not 
taken  in  excess,  would  appear  to  promote 
digestion,  and  to  exercise  a  favourable  influence 
on  the  system  at  large. 

It  has  been  observed  that  all  tribes  of  people 
that  have  made  the  least  advances  in  the  arts 
of  life,  either  by  accidental  observation  or  by 
tradition,  have  become  acquainted  with  the 
process  of  fermentation,  and  have  indulged  in 
the  use  of  certain  species  of  vinous  liquors. 
The  making  of  wine  is  among  the  first  transac- 
tions that  are  recorded  of  Noah  after  he  left  the 
ark,  and  the  experiment  which  he  made  of  its 
effects  has  been  but  too  frequently  repeated  by 
his  progeny.  The  basis  of  all  vinous  liquors 
being  the  saccharine  principle,  the  grape  has 
been  naturally  had  recourse  to  in  all  those  parts 
of  the  world  which  are  adapted  to  the  growth 
of  the  vine ;  in  the  more  northern  regions,  as 
in  our  own  island,  different  species  of  grains 
are  employed,  in  which  the  sugar  is  evolved  by 
an  artificial  process,  while  in  the  torrid  zone, 

*  Bostock's  Physiol,  v.  ii.  p.  469,  70. 


DIGESTION. 


15 


other  saccharine  juices,  procured  from  certain 
tropical  plants,  are  employed  for  the  same  pur- 
pose. The  fermented  liquors  of  our  own  coun- 
try generally  contain  a  considerable  quantity  of 
mucilaginous  and  saccharine  matter,  which  still 
remains  undecomposed,  and  which  is  directly 
nutritive ;  but  fully  fermented  wines  are  only 
indirectly  so,  as  aiding  the  digestive  powers 
by  their  stimulating  effect  on  the  stomach. 

It  is  generally  admitted,  that  the  operation 
of  alcohol,  when  properly  diluted,  and  when 
taken  in  moderate  quantity,  is  favourable  to  the 
health  of  most  individuals  who  are  engaged  in 
laborious  pursuits,  and  have  occasion  to  exert 
the  full  powers  of  the  system.  But  the  almost 
irresistible  temptation  to  excess,  and  the  fatal 
consequences  which  thence  ensue,  both  to  our 
physical  and  our  mental  constitution,  have  long 
been  the  subject  of  deep  regret  and  severe  re- 
prehension, both  to  the  physician  and  the  mo- 
ralist, and  it  may  be  asserted,  that  of  all  the 
gifts  which  providence  has  bestowed  on  the 
human  race,  there  is  none  which,  according  to 
the  present  state  of  society,  would  appear  of 
such  dubious  advantage  as  the  knowledge  of 
the  process  by  which  one  of  the  most  nutritive 
articles  of  diet  is  converted  into  one  of  the 
deadliest  poisons. 

We  have  now  to  notice  a  class  of  substances 
very  generally  employed  in  diet,  which  are  not 
in  themselves  nutritive,  but  are  added  to  our 
food,  for  the  purpose  of  rendering  it  more  agree- 
able to  the  palate.  These  are  the  various  arti- 
cles styled  condiments ;  they  may  be  classed 
under  the  two  heads  of  salts  and  spices.  There 
is  so  very  general  a  disposition  among  all  classes 
of  people  in  all  countries  to  relish  sapid  food, 
that  we  are  led  to  conceive  that  there  must  be 
some  final  cause  for  it,  independent  of  the  mere 
gratification  of  the  senses,  or  that  this  gratifica- 
tion is  made  subservient  to  some  more  import- 
ant purpose.  With  respect  to  what  is  termed 
common  salt,  the  muriate  of  soda,  we  observe, 
in  many  cases,  the  same  relish  for  it  among  the 
lower  animals  as  in  man.  We  have  well  au- 
thenticated accounts  given  us,  by  various  tra- 
vellers and  naturalists,  of  the  extraordinary 
efforts  which  are  made  by  the  beasts  of  prey 
which  inhabit  the  great  African  and  American 
continents,  to  obtain  it.*  We  can  scarcely 
therefore  doubt  that  it  must  be,  in  some  way  or 
other,  essential  to  the  well-being  of  the  animal; 
but  whether  it  directly  promotes  the  process  of 
chymification,  or  whether  it  be  taken  into  the 
stomach,  for  the  purpose  of  being  transmitted 
to  the  blood,  and  thus  furnishing  to  the  system 
the  portion  of  saline  matter  which  is  always 
present  in  the  animal  fluids,  must  be  considered 
as  entirely  conjectural.f 

The  other  division  of  condiments,  the  spices, 
are  very  numerous,  and  are  derived  from  vari- 
ous sources,  but  are  chiefly  of  vegetable  origin. 
They  are  generally  of  a  stimulating  nature,  and 

*  Among  these  we  may  select  the  account  given 
us  by  Mr.  Hodgson,  in  his  interesting  letters  from 
North  America,  vol.  i.  p.  240,  1,  note. 

t  Haller,  El.  Phys.  xix.  3,  11  ;  Fordyce  on 
Digestion,  p.  55. 


such  as  may  be  supposed  to  act,  in  the  first  in- 
stance, on  the  nervous  system.  Some  of  them 
increase  the  action  of  the  heart  and  arteries, 
and  some  of  them  augment  the  secretions  or 
excretions,  but  they  differ  essentially  from 
alcohol,  in  not  producing  any  thing  resembling 
intoxication  and  the  subsequent  exhaustion. 
Thus  they  are  much  less  injurious  to  the  con- 
stitution, even  when  taken  to  excess,  and  are 
seldom  liable  to  any  stronger  imputation  than 
that  of  being  useless.  They  afford  some  of  the 
most  remarkable  examples  of  the  effect  of  habit 
on  the  system,  in  changing  or  modifying  our 
.original  perceptions,  for  it  is  very  generally 
found  that  those  substances  to  which  we  be- 
come, in  process  of  time,  the  most  attached, 
are  such  as,  in  the  first  instance,  were  not  only 
perfectly  indifferent,  but  even  positively  dis- 
gusting. 

Before  we  quit  this  part  of  the  subject  it 
remains  for  us  to  say  a  few  words  respecting 
the  class  of  substances  which  are  properly 
termed  medicaments.  The  medicaments  are 
nearly  related  to  the  condiments  in  their  action 
on  the  system,  but  with  this  difference,  that 
they  are  not  only  disagreeable  to  the  palate,  but 
are,  for  the  most  part,  incapable  of  being  re- 
conciled to  it  by  habit.  But  there  is  in  fact 
no  exact  line  of  demarcation  between  them  ; 
many  of  the  articles  which  are  usually  consi- 
dered as  condiments,  being  not  unfrequently 
used  in  medicine,  and  some  of  what  are  gene- 
rally regarded  as  the  most  active  and  nauseous 
medicines,  being  employed  by  some  individuals 
as  agreeable  condiments.  Both  these  classes 
of  substances  appear  to  differ  in  one  essential 
particular  from  what  are  more  properly  re- 
garded as  articles  of  diet,  that  while  it  is  essen- 
tial to  the  operation  of  the  latter,  that  they 
should  be  decomposed,  and  probably  resolved 
into  their  constituent  elements,  the  specific 
effect  of  the  former  seems  to  depend  upon  their 
acting  on  the  stomach  in  their  entire  state. 
Nearly  connected  to  this  class  of  substances, 
and  indeed  differing  from  it  only  in  degree,  are 
the  articles  that  are  usually  termed  poisons. 
The  term  may,  however,  be  regarded  as  entirely 
a  popular  designation,  for  as  there  is  no  active 
medicine  which  may  not  immediately  destroy 
life  by  an  excessive  or  improper  administra- 
tion, so  there  are  no  substances,  among  those 
which  are  usually  considered  as  poisonous,  which 
may  not,  under  certain  circumstances,  prove 
valuable  medical  agents. 

III.  An  account  of  the  changes  which  the 
food  experiences  in  the  process  of  digestion. — 
We  now  proceed  to  the  consideration  of  the 
third  subject  which  we  proposed  for  our  in- 
quiry, the  nature  of  the  change  which  the  food 
undergoes  during  the  process  of  digestion.  In 
prosecuting  this  inquiry  we  shall  consider  in 
succession  the  various  processes  by  which  the 
aliment,  after  being  received  into  the  mouth,  is 
brought  into  the  state  of  chyle.  These  changes 
may  be  reduced  essentially  to  three ;  the  me- 
chanical division  of  the  food,  as  effected  by  the 
operations  of  maceration,  mastication,  and  tri- 
turation; the  conversion  of  the  alimentary  mass 
into  chyme,  by  the  action  of  the  gastric  juice ; 


16 


DIGESTION. 


and  lastly,  the  conversion  of  chyme  into  chyle 
in  the  duodenum.* 

After  the  account  which  we  have  given  above 
of  the  organs  of  mastication,  nothing  further 
remains  for  us  to  say  on  the  first  part  of  the 
process ;  we  may  therefore  conceive  that  the 
food,  after  it  has  been  mechanically  divided  by 
means  of  the  teeth  or  any  analogous  organ,  is 
conveyed  to  the  stomach,  in  order  to  be  acted 
on  by  the  gastric  juice  and  converted  into 
chyme.f  The  process  of  chymification  consists 
in  a  certain  chemical  change,  by  which  the 
aliment,  from  whatever  source  it  may  have  been 
derived,  and  whatever  may  have  been  its  origi- 
nal constitution,  is  converted  into  a  uniform 
pultaceous  mass,  having  certain  specific  pro- 
perties, which  are  different  from  those  of  the 
substances  from  which  it  is  formed. 

And  we  may  here  observe,  that  this  kind  of 
change,  which  has  been  frequently  spoken  of 
as  something  of  a  mysterious  or  inexplicable 
nature,  is  perfectly  analogous  to  what  takes 
place  in  all  chemical  action,  where  the  addition 
of  a  new  agent  imparts  new  properties  to  the 
mixture.  The  supposed  difficulty  in  this  case 
has  arisen  from  an  indistinct  conception  in  the 
minds  of  many  physiologists,  both  of  the  nature 
of  chemical  action  generally,  and  of  the  appro- 
priate powers  which  belong  to  a  living  orga- 
nized system.  The  essential  and  exclusive 
functions  of  vitality  may  probably  be  all  re- 
duced to  two  great  principles  of  sensation  and 
motion,  as  depending  primarily  upon  the  action 
of  the  nerves  and  the  muscles.  Chemical  affi- 
nity is  independent  of  these  principles,  but  it 
is,  in  various  ways,  modified  by  their  operation, 
by  bringing  the  agents  into  contact,  by  separa- 
ting them  from  each  other,  and  thus  enabling 
them  to  produce  new  compounds,  and  when 
the  compounds  are  formed,  by  removing  them 
from  the  further  action  of  the  agents,  and  by 
conveying  them  to  the  situations  when  they  are 
required,  for  the  exercise  of  some  new  function. 
In  the  present  case  the  glands  of  the  stomach 
secrete  a  fluid  possessed  of  specific  properties  ; 
by  the  act  of  deglutition,  and  by  the  muscular 
contraction  of  the  stomach  itself,  the  alimentary 
mass  is  conveyed  to  the  part  where  it  may  be 
brought  into  contact  and  mixed  with  this  fluid. 
Each  portion  of  the  aliment  is  successively 
subjected  to  the  due  action  of  this  agent,  and 
when  the  process  is  completed,  it  is  carried 
through  the  pylorus  out  of  the  stomach,  while 
a  new  portion  of  aliment  takes  its  place  and 
goes  through  the  same  process. 

In  this  part  of  our  subject  there  are  two 

*  See  on  this  subject  Magendie,  Physiol,  t.  ii. 
p.  81,  2;  Dr.  Prout's  paper  in  Ann.  Phil.  vol.  xiii 
and  xiv.  and  Dr.  Philip's  Inquiry,  ch.  vii.  sect.  1. 

f  It  is  necessary  to  remark  in  this  p'.ace,  that 
most  of  the  older  physiologists,  and  some  even  of  a 
later  period,  have  employed  the  terms  chyme  and 
chyle  indiscriminately,  or  at  least  have  not  made 
any  accurate  distinction  between  them.  The  words 
j^iAo?  and  X"!*'";  appea''  to  be  nearly  synonymous  in 
their  original  acceptation;  see  Castelli,  Lexicon, 
and  Stephens,  Thes.  in  loco.  The  latest  physiolo- 
gists have,  however,  for  the  most  part,  employed 
the  two  terms  in  the  restricted  sense  which  is 
adopted  in  this  article. 


points  which  will  require  our  particular  atten- 
tion ;  first,  we  must  ascertain  the  properties  of 
chyme,  and  secondly,  those  of  the  gastric  juice. 
It  is  commonly  stated,  that  from  whatever 
source  the  chyme  is  derived,  provided  the 
stomach  be  in  a  healthy  state,  its  properties  are 
always  the  same,*  and  it  must  be  admitted 
that,  as  a  general  principle,  this  would  appear 
to  be  the  case.  In  animals  of  the  same  species, 
notwithstanding  the  miscellaneous  nature  of  the 
substances  that  are  employed  in  diet,  the  result 
of  the  complete  action  of  the  stomach  is  a  mass 
of  uniform  consistence,  in  which  the  peculiar 
sensible  properties  of  the  articles  of  food  cannot 
be  recognized.  But  this  statement  must  be  re- 
ceived with  certain  limitations,  and  is  only  ap- 
plicable to  the  ordinary  diet,  for  we  have  reason 
to  believe,  not  only  that  the  chyme  produced 
from  animal  matter  differs  from  that  of  vegetable 
origin,  but  even  that  different  species  of  vege- 
table aliment  produce  a  different  kind  of 
chyme.  The  chyme  from  fruits  or  green  vege- 
table matter  is  notoriously  more  disposed  to 
pass  into  the  acetous  fermentation  than  chyme 
formed  from  farina  or  gluten,  a  circumstance 
which  must  depend  upon  a  difference  in  their 
chemical  constitution.  We  also  know  that  the 
same  kind  of  aliment  is  differently  acted  on  by 
the  gastric  juice  of  different  individuals;  but 
this  may  probably  depend  upon  some  variation 
in  the  nature  of  the  gastric  juice  itself,  and  is 
therefore  to  be  referred  to  a  different  principle. 

Disregarding,  however,  for  the  present  what 
may  appear  only  exceptions  to  the  general  rule, 
we  must  inquire  into  the  nature  of  the  sub- 
stance which  is  found,  under  ordinary  circum- 
stances, in  the  proper  digestive  stomach,  after 
it  has  experienced  the  full  operation  of  the 
gastric  juice.  Although  many  observations 
have  been  made  upon  the  pultaceous  mass 
which  is  thus  produced,  our  information  re- 
specting it  is  not  very  precise ;  we  are  told 
little  more  than  that  the  texture,  odour,  and 
flavour  of  the  food  employed  are  no  longer 
perceptible,  and  it  is  said  to  have  slightly  acid 
properties,  or  rather  to  be  disposed  to  pass  into 
the  acetous  fermentation.  As  we  remarked 
above,  the  change  which  the  food  undergoes  is 
to  be  regarded  as  the  result  of  chemical  action, 
where  not  merely  the  mechanical  texture  and 
the  physical  properties  of  the  substance  are 
changed,  but  where  it  has  acquired  new  chemi- 
cal relations. 

This  conclusion  is  deduced  from  a  number 
of  very  interesting  experiments,  which  were 
performed  successively  by  Reaumur,  Stevens, 
and  Spallanzani,  and  which  consisted  in  insert- 
ing different  kinds  of  alimentary  matter  into 
perforated  tubes  or  balls,  or  inclosing  them  in 
pieces  of  porous  cloth.  These  were  introduced 
into  the  stomach,  and  after  some  time  were  re- 
moved from  it  and  examined,  when  it  was 
found  that  the  inclosed  substances  had  under- 
gone more  or  less  completely  the  process  of 
chymification,  while  the  enclosing  body  was 

*  Haller,  El.  Phys.  xix.  4,  31 ;  see  the  remarks 
of  Tiedemann  and  Gmelin  in  the  third  section  of 
their  researches. 


DIGESTION. 


17 


not  acted  upon,  thus  proving  decisively  that 
the  effect  was  not  produced  by  a  mere  mecha- 
nical operation*  The  results  of  these  experi- 
ments have  been  confirmed  by  some  remark- 
able facts,  which  bear  still  more  directly  upon 
the  point  under  investigation,  where  certain  in- 
dividuals have  had  preternatural  openings  made 
into  the  stomach,  either  from  accident  or  dis- 
ease, while  the  functions  of  the  part  appear  to 
have  been  but  little,  if  at  all,  impaired.  By 
this  means  the  operation  that  is  going  forwards 
in  this  organ  may  be  minutely  watched  in  all 
its  various  stages,  and  we  are  enabled  to  ob- 
serve the  change  which  the  food  undergoes 
from  the  time  that  it  enters  the  stomach  until 
it  passes  from  the  pylorus,  and  to  compare  the 
changes  which  the  different  kinds  of  food  ex- 
perience during  the  progress  of  the  whole  mass. 

A  case  of  this  kind  is  related  by  Circaud, 
where  an  individual  lived  many  years  with  a 
fistulous  opening  into  the  stomach  ;f  but  a 
much  more  remarkable  case  of  the  same  de- 
scription has  been  lately  communicated  by  Dr. 
Beaumont.  The  individual  in  question  was 
wounded,  early  in  life,  by  a  shot  in  the  epigas- 
tric region,  which  perforated  the  stomach. 
After  some  time  the  wounded  part  healed, 
with  the  exception  of  an  aperture  two  and  a 
half  inches  in  diameter,  which  communicated 
with  the  stomach.  He  lived  many  years  in 
this  state,  in  perfect  health  and  vigour,  so  as  to 
be  capable  of  following  a  laborious  occupation, 
while  the  fistulous  opening  still  remained. 
Under  these  circumstances  he  was  made  the 
subject  of  experiment  by  Dr.  Beaumont,  who 
for  the  space  of  eight  years  continued  his  ob- 
servations, with  great  assiduity  and  minuteness, 
on  the  action  of  the  stomach  both  in  its  ordi- 
nary state,  and  when  subjected  to  different  con- 
ditions, for  the  immediate  purpose  of  the  expe- 
riment. We  may  remark  generally,  that  the 
results  of  the  experiments  confirm  those  of 
Spallanzani  in  their  most  essential  particulars, 
and  at  the  same  time  enable  us  to  decide  upon 
some  points  which  were  left  imperfect  by  that 
naturalist. I 

Among  the  more  important  points  respecting 
the  formation  of  chyme,  which  appear  to  be 
confirmed  by  the  experiments  of  Dr.  Beau- 
mont, are  the  following;  that  the  different 
kinds  of  aliment  all  require  to  undergo  the 
same  process,  by  means  of  the  gastric  fluid, 
in  order  to  be  reduced  into  chyme ;  that  the 
rapidity  of  the  process  differs  considerably 
according  to  the  delicacy  of  their  natural  tex- 
ture or  the  degree  of  their  mechanical  division; 
that  the  saliva  is  of  no  specific  use  in  the  con- 
version of  aliment  into  chyme;  that  animal 
substances  are  more  easily  converted  into 
chyme  than  vegetables ;  and  that  oily  sub- 
stances, although  they  contain  a  large  quantity 

*  Reaumur,  Med.  Acad,  pour  1752,  p.  266  et  seq. 
and  p.  461  et  seq.  ;  Stevens,  De  Alim.  Concoct, 
cap.  xii.  ex.  1  ...  9  and  11  .  .  .23;  Spallanzani, 
Exp&r.  sur  la  Digest,  passim  ;  Blumenbach,  Inst. 
Physiol.  § 358, 9  ;  Monro  (Tert. )  Elem.  v.  i.  p.  532. 

J-  Journ.  de  Phys.  t.  liii.  p.  156,  7. 

X  Beaumont  on  the  Gastric  Juice  and  on  Diges- 
tion, sect.  1,  5. 

VOL.  II. 


of  nutriment,  are  comparatively  difficult  of 

digestion.* 

We  must  next  inquire  into  the  physical  and 
chemical  properties  of  the  gastric  juice,  the 
fluid  secreted  from  the  interior  of  the  stomach, 
by  which  the  change  in  the  aliment,  that  we 
have  been  describing,  is  produced.  Since  the 
publication  of  Reaumur's  experiments,  about 
the  middle  of  the  last  century,  the  general 
opinion  among  physiologists  and  chemists  has 
been,  that  the  gastric  juice  possesses  specific 
properties,  which  enable  it  to  dissolve  or  com- 
bine with  the  aliment;  and  many  experiments 
have  been  performed  for  the  purpose  of  ascer- 
taining the  chemical  nature  of  the  secretion, 
so  as  to  account  for  the  powerful  action  which 
it  appears  to  possess  over  such  a  great  variety 
of  substances.  Besides  the  more  general  ac- 
count which  we  have  of  the  gastric  juice  by 
Boerhaave,  Haller,  and  Reaumur,f  it  was  made 
the  subject  of  an  elaborate  series  of  expe- 
riments by  Spallanzani;]:  it  was  also  analyzed 
by  Scopoli§  and  by  Carminati,|[  and  has  been 
lately  examined  by  Dr.  Prout,5[  and  by  MM. 
Tiedemann  and  Gmelin.**  The  result  is,  upon 
the  whole,  rather  unsatisfactory,  or  at  least  it 
may  be  said,  that  nothing  has  been  detected 
in  the  fluid,  which  seems  to  account  for  or 
explain  the  powerful  action  which  it  exercises 
on  the  alimentary  substances  subjected  to  its 
influence. ft  All  that  we  learn  is,  that  the 
gastric  juice  contains  certain  saline  substances 
in  small  quantity,  more  especially  the  muriate 
of  soda,  in  common  with  the  other  animal 
fluids,  but  that  it  does  not  differ  essentially, 
in  its  chemical  properties,  from  saliva,  or  from 
the  secretions  of  mucous  membranes  gene- 
rally. Dr.  Prout  indeed  informs  us,  that  a 
quantity  of  muriatic  acid  is  always  present  in 
the  stomach  during  digestion  ;}}  but  as  there 
does  not  seem  to  be  any  decisive  evidence  of  its 
appearance  previously  to  the  introduction  of 
the  food  into  the  stomach,  we  ought  probably 
rather  to  consider  it  as  developed  by  the  pro- 
cess of  digestion,  than  as  entering  into  the 
constitution  of  the  gastric  juice ;  nor  indeed, 
if  it  were  so,  are  we  able  to  explain  the  mode 
in  which  it  operates  in  converting  aliment  into 
chyme. §§  This  apparent  difficulty  in  account- 
ing for  the  mode  in  which  chyme  is  formed  by 
the  gastric  juice,  and  the  supposed  inadequacy 

*  Beaumont,  page  275  .  .  8  et  alibi. 

t  Boerhaave,  Praelect.  §  77  et  seq. ;  Haller,  El. 
Phys.  xix.  1.  15.  et  4.  20;  Reaumur,  Mem.  Acad, 
pour  1752,  p.  480,  495. 

t  Ut  supra,  §  81  et  seq.  145,  185,  192. 

§  In  Spallanzani,  §  244. 

||  Jour.  Phys.  t.  xxiv.  p.  168  et  seq. 

if  Ann.  Phil.  v.  xiii.  p.  13. 

**  Rechcrchcs  sur  la  Digestion,  trad,  par  Jour- 
dan. 

tt  Henry's  Chem.  v.  ii.  p.  410,  1. 

it  Phil.  Trans,  for  1824,  p.  45  et  seq. 

The  presence  of  acid  in  the  stomach,  in  its 
healthy  state,  has  been  made  the  subject  of  in- 
quiry by  many  experimentalists,  and  of  much  con- 
troversy ;  the  result  is  that  the  older  physiologists 
generally  denied  its  existence,  except  in  morbid 
states  of  the  stomach,  while  many  of  the  most 
eminent  modern  physiologists  believe  it  to  be 
always  present,  and  indeed  regard  it  as  an  esscn- 

C 


18 


DIGESTION. 


of  tlie  agent  to  this  purpose,  has  led  to  many 
singular  theoretical  opinions,  which  will  be 
noticed  in  a  subsequent  part  of  this  article.* 

But  in  whatever  way,  or  upon  whatever 
principle  we  may  explain  the  action  of  the 
gastric  fluid  upon  the  aliment,  we  are  irre- 
sistibly led  to  the  conclusion,  that  it  is  the 
physical  agent  which  produces  the  effect,  not 
only  from  those  cases,  where  in  consequence 
of  a  preternatural  opening  into  the  stomach 
we  are  able  to  observe  the  actual  phenomena 
of  digestion,  but  still  more  so,  by  the  expe- 
riments on  what  has  been  termed  artificial  di- 
gestion, especially  those  of  Spallanzani  and 
Beaumont,  where  the  gastric  juice  has  been 
procured,  and  applied  out  of  the  stomach, 
and  where  the  process  of  chymification  has 
proceeded,  as  nearly  resembling  that  in  the 
stomach  itself  as  might  reasonably  be  ex- 
pected, considering  the  unavoidable  imper- 
fection of  the  experiment.  This  imperfection 
respects  both  the  mode  of  obtaining  the  gastric 
juice  itself,  and  the  mode  of  applying  it  to 
the  aliment.  We  reduce  the  action  of  the 
stomach  into  somewhat  of  an  unnatural  con- 
dition in  order  to  procure  the  secretion,  and 
in  the  application  of  it  we  are  deprived  of  the 
contractile  motion  of  the  organ ;  yet,  not- 
withstanding these  unavoidable  circumstances, 
the  substances  were  reduced  to  a  state  very 
considerably  resembling  that  of  chyme.  That 
this  change  was  not  produced  by  a  mere  me- 
chanical action  is  proved  by  the  circumstance, 
that  the  change  in  the  substances  operated  on 
bore  no  proportion  to  the  hardness  of  their 
texture  or  other  physical  properties.  Thus  we 
find  that  the  gastric  fluid  acts  upon  dense 
membrane,  and  in  some  cases,  even  upon 
bone,  while  there  are  other  substances,  of  a 
very  delicate  texture,  which  are  not  affected 
by  it.  This  kind  of  selection  of  certain  sub- 
stances in  preference  to  others  bears  so  close 
an  analogy  to  the  operation  of  chemical  affinity, 
that  we  ought  not  to  refuse  our  assent  to  the 
idea  of  their  belonging  to  the  same  class  of 

tial  agent  in  the  process.  From  the  first  part  of 
this  remark  we  must,  however,  except  Vanhelmont 
and  Willis;  Ortus  Med.  p.  164  .  .  7  et  alibi  ;  De 
Ferment,  op.  t.  i.  p.  25.  See  Haller  in  Boerhaave, 
Praelect.  not.  ad  §  77,  and  El.  Phys.  xix.  1.  15, 
and  4.  29 ;  Fordyce,  p.  150,  1  ;  Spallanzani, 
§  239  . .  245  ;  Hunter,  p.  293  et  seq. ;  Circaud,  ut 
supra;  Dumas,  El.  Phys.  t.  i.  p.  278  . .  0  ;  Tiede- 
mann  et  Gmelin,  Recherches,  t.  i.  p.  166, 
7.  It  may  be  proper  to  remark  that  Leuret  and 
Lassaigne  do  not  admit  of  the  presence  of  this 
acid  ;  they,  on  the  contrary,  suppose  that  the 
gastric  juice  owes  its  acid  properties  to  the  lactic 
acid  ;  Recherches  Physiol,  et  Cliimiques,  p.  114.  .7; 
Dr.  Prout  has,  however,  as  we  conceive,  satisfac- 
torily answered  their  objections  to  his  experiments ; 
Ann.  Phil.  v.  xii.  p.  406.  Dr.  Carswell  considers 
acidity  to  be  the  essential  and  active  property 
of  the  gastric  juice  ;  Pathol.  Anat.  fas.  5. 

*  Montegre  has  lately  performed  a  series  of  ex- 
periments, the  results  of  which  lead  him  to  deny 
the  specific  action  of  the  gastric  juice  ;  Exper.  sur 
la  Digestion,  p.  43,  4.  But,  notwithstanding  the 
apparent  accuracy  with  which  they  were  conducted, 
we  cannot  but  suspect  some  source  of  error,  seeing 
how  much  they  are  at  variance  with  all  our  other 
information  on  the  subject. 


actions,  although  it  occurs  under  circum- 
stances where  we  might  not  have  expected  to 
find  it. 

There  are  two  other  properties  of  the  gastric 
juice,  besides  its  solvent  power,  which  are  at 
least  as  difficult  to  account  for,  but  of  which 
we  seem  to  have  very  complete  evidence, — 
its  property  of  coagulating  albumen,  and  that 
of  preventing  putrefaction.  It  is  the  former 
of  these  properties  which  we  employ  in  mak- 
ing cheese,  cheese  being  essentially  the  albu- 
minous part  of  milk,  coagulated  by  means  of 
what  is  termed  rennet,  a  fluid  consisting  of  the 
infusion  of  the  digestive  stomach  of  the  calf. 
This  is  unequivocally  a  chemical  change,  yet 
it  is  very  difficult  to  explain  it  upon  any  che- 
mical principle,  i.  e.  to  refer  this  individual 
case  to  any  series  of  facts,  with  which  it  can 
be  connected.*  We  can  only  say  in  this 
instance,  as  in  so  many  others  in  the  physical 
sciences,  that  although  the  fact  is  clearly 
ascertained,  its  efficient  cause  still  remains 
doubtful. 

We  are  compelled  to  make  the  same  re- 
mark with  regard  to  the  other  property  of  the 
gastric  juice,  to  which  we  have  referred  above, 
its  antiseptic  power.  Of  the  fact,  however, 
we  are  well  assured,  both  as  occurring  in  the 
natural  process  of  digestion,  and  in  the  expe- 
riments that  have  been  made  out  of  the  body. 
It  is  not  uncommon  for  carnivorous  animals 
to  take  their  food  in  a  half  putrid  state,  when 
it  is  found  that  the  first  action  of  the  gastric 
juice  is  to  remove  the  fcetor;  and  an  effect  of 
precisely  the  same  kind  was  noticed  by  Spal- 
lanzani in  his  experiments.-^  Here  again  we 
have  a  chemical  change,  the  nature  of  which 
we  cannot  explain;  it  is,  however,  a  circum- 
stance which  may  appear  less  remarkable,  with 
respect  to  the  subject  now  under  consideration, 
because  the  action  of  antiseptics  generally  is 
one  which  we  find  it  difficult  to  refer  to  any 
general  principles. 

Respecting  the  process  of  chymification  it 
only  remains  for  us  to  remark,  that  the  con- 
tractile action  of  the  stomach  is  admirably 
fitted  to  aid  the  chemical  action  of  the  secreted 
fluids  ;  the  vermicular  motion  of  the  organ  has 
the  effect  of  keeping  the  whole  of  its  contents 
in  a  gradual  state  of  progression  from  the 
catdia  to  the  pylorus,  while,  at  the  same  time, 
each  individual  portion  of  the  aliment  is  com- 
pletely mixed  together,  and  brought  into  the 

*  This  difficulty  appears  to  be  increased  by  the 
amount  of  effect  which  is  produced  by  the  very 
small  quantity  of  the  agent ;  Fordyce  informs  us, 
that  a  very  few  grains  of  the  inner  coat  of  the 
stomach,  a  very  small  proportion  of  which  must 
have  consisted  of  the  secretion,  was  capable,  when 
infused  in  water,  of  coagulating  more  than  one 
hundred  parts  of  milk;  p.  57,9;  176  et  seq.; 
Prout,  Ann.  Phil.  v.  xiij.  p.  13  et  seq. 

t  Exper.  §  250.. 2  et  alibi ;  see  also  Hunter  on  the 
Anim.  CEcon.  p.  204.  Montegre  does  not  admit 
of  this  property,  and  would  appear  to  doubt  also 
of  the  coagulating  power  of  the  gastric  juice,  p.  21 
et  alibi  ;  the  same  opinion  is  also  maintained  by 
Dr.  Thackrah,  lect.  p.  14;  but  it  would  require  a 
very  powerful  series  of  negative  facts  to  controvert 
the  strong  evidence  that  we  possess  on  this 
subject. 


DIGESTION. 


19 


proper  state  for  being  received  into  the  duode- 
num. The  undulatory  motion  of  the  stomach 
is  more  especially  effected  by  the  circular  fibres, 
while  the  longitudinal  fibres  are  more  effective 
in  the  progressive  motion  of  its  contents  from 
the  cardia  to  the  pylorus. 

The  alimentary  mass  is  now  to  undergo  the 
last  of  the  three  changes  to  which  we  referred 
above,  its  conversion  from  chyme  into  chyle. 
These  substances  are  obviously  different  from 
each  other  in  their  sensible  properties,  but 
respecting  the  exact  nature  of  this  difference, 
the  change  which  they  experience,  or  the  mode 
in  which  it  is  produced,  we  have  little  certain 
information.  The  fact  appears  to  be,  that  as 
soon  as  the  uniform  pultaceous  mass,  which 
composes  the  chyme,  enters  the  duodenum, 
it  begins  to  separate  into  two  parts,  a  white 
creamy  substance,  which  constitutes  the  chyle, 
and  a  residuary  mass,  which  is  gradually  con- 
verted into  faces,  and  is  propelled  along  the 
course  of  the  intestine,  in  order  to  be  finally 
expelled  from  the  system*  Although  no  point 
in  physiology  appears  to  be  more  clearly  as- 
certained than  that  chyle,  properly  so  called, 
is  never  found  in  the  stomach,  and  that  the 
duodenum  is  the  appropriate  organ  for  its  pro- 
duction, yet  owing  partly  to  the  inaccurate 
mode  in  which  the  terms  have  been  employed, 
and  partly  to  the  inaccuracy  of  our  obser- 
vation, some  writers,  even  in  our  own  times,f 
have  spoken  of  chyle  as  being  formed  in  the 
stomach,  and  have  conceived  that  the  only 
change  which  was  effected  in  the  duodenum 
was  the  separation  of  the  chyle  from  the  re- 
mainder of  the  mass. | 

With  respect  to  the  mode  in  which  this 
change  is  brought  about,  or  the  agent  by  which 
it  is  effected,  we  have  little  to  offer  except  con- 
jecture. The  secretions  of  the  liver  and  the 
pancreas  are,  each  of  them,  conveyed  into  the 
duodenum,  and  it  has  been  stated  that  the 
completion  of  the  chyle  takes  place  exactly  at 
the  part  where  the  bile  and  the  pancreatic  juice 
enter  into  the  intestines.  Of  this,  however, 
we  do  not  possess  any  direct  evidence,  and 
the  fact,  that  in  certain  cases  of  disease  or  mal- 
formation, the  process  of  chylification  has  gone 
on,  nearly  in  its  ordinary  course,  although  the 
fluids  in  question  have  not  been  transmitted 
into  the  intestine,§  appears  to  furnish  a  de- 

*  Prout,  ut  supra,  v.  xiii.  p.  12  et  alibi.  The 
difference  between  chyme  and  chyle,  as  well  as  the 
different  organs  in  which  they  are  elaborated,  was 
well  known  to  some  of  the  older  writers,  although 
not  acknowledged  ;  see  Juncker,  Conspect.  Physiol, 
tab.  11  et25;  Vanhclmont,  Ortus  Med.  p.  167,  8, 
and  Baglivi,  Diss.  3.  circa  bilem. 

t  Home,  in  Phil.  Trans,  for  1807,  p.  88,  9. 

t  On  this  subject  the  reader  is  referred  to  the 
following  works:  Boerhaave,  Praelect.  §  90  .  .  5  ; 
Haller,  ibid,  in  notis,  Prim.  Lin.  §  635  .  .  8  et  alibi, 
and  El.  Phys.  xviii.  4.  24,  31  et  xxiv.  2.  1 ;  Hunter, 
Anim.  CEcon.  p.  213  ;  Fordyce,  ut  supra,  passim  ; 
Bell's  Anat.  v.  iv.  p.  65  et  seq.  ;  Monro's  (Tert.) 
Elera.  v.  i.  p.  552 ;  Richerand,  El.  Physiol.  §11, 
25. 

$  The  experiments  of  Sir  B.  Brodie,  in  which 
the  formation  of  chyle  appears  to  have  been  sus- 
pended by  tying  the  biliary  duct,  although  inte- 


nsive objection  to  the  hypothesis.  Some  phy- 
siologists have  conceived  that  the  duodenum 
itself  secretes  a  specific  fluid,  analogous  to 
that  in  the  stomach,  by  which  the  process  of 
chylification  is  effected ;  but  we  have  no  evi- 
dence of  the  existence  of  this  fluid,  except  the 
supposed  necessity  to  explain  the  effects  that 
are  produced.  In  this  deficiency  of  direct  evi- 
dence we  appear  to  be  reduced  to  the  sup- 
position, that  the  conversion  of  chyme  into 
chyle  is  effected  partly  by  the  mutual  action 
of  its  constituent  elements  on  each  other,  aided 
perhaps,  in  some  degree,  by  the  intervention 
of  the  bile  and  the  pancreatic  juice.* 

We  have  various  analyses  of  chyle,  which 
appear  to  have  been  made  with  sufficient  accu- 
racy. It  is  a  white  opaque  substance,  re- 
sembling cream  in  its  appearance  and  phy- 
sical properties.  When  removed  from  the 
body,  it  shows  a  tendency  to  concrete  and 
undergoes  a  change  considerably  resembling 
the  coagulation  of  the  blood,  by  which  it  se- 
parates into  two  parts,  a  dense  white  coagulum, 
and  a  transparent  colourless  fluid,  analogous 
respectively  to  crassamentum  and  to  serum. 
The  chemical  properties  of  chyle  appear  very 
similar  to  those  of  the  blood,  and  it  also  re- 
sembles blood  in  the  nature  of  its  saline  con- 
tents; but  it  differs  from  it  in  containing  a 
portion  of  oil  as  one  of  its  essential  consti- 
tuents, while  in  the  blood  oil  is  only  an  occa- 
sional, and  probably  a  morbid  ingredient. f 

The  chemical  analysis  of  chyle  was  first 
made  by  Vauquelin,  who  employed  for  this 
purpose  the  contents  of  the  thoracic  duct  and 
large  lacteals  of  a  horse.  The  coagulum  from 
the  duct  was  observed  to  be  of  a  light  pink 
colour,  while  the  corresponding  part  from  the 
lacteals  was  nearly  white ;  but  it  is  not  ascer- 
tained how  far  this  difference  of  colour  de- 
pended upon  an  accidental  occurrence,  or 
whether  it  is  to  be  regarded  as  a  uniform  cir- 
cumstance. The  jcoagulum  contained  a  sub- 
stance which  bore  a  considerable  resemblance 
to  fibrine,  or  perhaps  more  correctly  possessed 
properties  intermediate  between  fibrine  and 
albumen.  The  liquid  part  of  the  chyle  was 
found  to  be  very  similar  to  the  serum  of  the 
blood,  differing  from  it  only  in  containing  a 
quantity  of  an  oily  or  fatty  substance;  like 
serum  it  exhibited  marks  of  an  uncombined 
alcali.J 

resting  and  important,  cannot  be  regarded  as  con- 
clusive, until  we  are  more  minutely  informed  of 
every  circumstance  connected  with  them;  Quart. 
Journ.  v.  xiv.  p.  341  et  seq. 

*  Dr.  Prout  conceives,  that  the  bile  is  the  prin- 
cipal agent  in  this  process  ;  and  that  when  it  is 
added  to  the  contents  of  the  duodenum,  it  separates 
the  chyle  by  a  kind  of  precipitation  ;  it  does  not, 
however,  appear  very  clearly  what  is  the  exact 
nature  of  the  chemical  action  which  takes  place. 

t  Fordyce,  p.  121 ;  Young's  Med.  Lit.  p.  516  ; 
Dumas,  t.  i.  p.  379  .  .  1  ;  Magendie,  t.  ii.  p.  154..8. 
Some  late  experiments  appear  indeed  to  prove  that 
a  certain  quantity  of  an  oily  matter  is  always  present 
in  the  blood  ;  but  the  proportion  in  the  chyle  is  at 
least  very  much  more  considerable. 

f  Ann.  Chim.  t.  lxxxi.  p.  113  et  seq.;  Ann.  Phil, 
v.  ii.  p.  220  et  seq.  We  have  some  experiments 
on  chyle  by  Emmert,  previous  to  those  of  Vauque- 

C  2 


20 


DIGESTION. 


The  next  experiments  which  we  possess  are 
those  of  Marcet,  who  operated  upon  the  chyle 
as  procured  from  dogs.  One  main  object  of 
his  researches  was  to  ascertain  how  far  chyle 
of  animal  origin  differs  from  that  from  vege- 
tables, and  he  had  the  food  of  the  dogs  regu- 
lated accordingly.  His  results  with  regard  to 
the  general  nature  and  properties  of  chyle  cor- 
respond very  exactly  with  those  of  Vauquelin. 
He  found  the  coagulum  to  have  a  pink  colour, 
and  to  contain  a  fibrous  or  filamentous  sub- 
stance, while  the  liquid  part  contained  a  quan- 
tity of  an  oily  matter,  which  floated  on  its 
surface  like  cream.  This  oily  matter  appeared, 
however,  to  be  confined  to  the  animal  chyle, 
and  it  is  remarked  generally,  that  this  bore 
more  resemblance  to  blood  than  the  chyle  from 
vegetables.  They  contained  the  same  saline 
ingredients,  but  the  solid  residuum  of  the 
animal  chyle  was  considerably  greater;  and 
as  the  vegetable  chyle,  when  submitted  to 
destructive  distillation,  was  found  to  contain 
much  more  carbon,  it  was  inferred  that  the 
animal  chyle  must  have  contained  proportion- 
ably  more  hydrogen  and  nitrogen.*  Upon 
these  experiments  we  may  remark,  that  the 
difference  between  the  animal  and  the  vege- 
table chyle  in  this  case  might  perhaps  depend 
in  some  degree  upon  vegetable  food  being  less 
adapted  to  the  digestive  organs  of  the  dog  ; 
because  the  chyle  of  the  horse,  as  examined  by 
Vauquelin,  appeared  to  be  more  completely 
animalized,  although  it  must  have  been  derived 
from  vegetable  diet. 

The  experiments  of  Dr.  Prout  agreed  gene- 
rally with  those  of  Vauquelin  and  Marcet ; 
he  found  the  coagulum  and  the  fluid  part 
analogous  to  the  two  components  of  the  blood, 
and  he  likewise  observed  the  oily  matter.  He 
compared  the  chyle  derived  from  animal,  with 
that  from  vegetable  food,  and  detected  the  oil 
in  both  of  them,  and,  upon  the  whole,  he 
found  them  to  differ  less  than  was  supposed 
by  Marcet ;  he  remarks,  however,  that  the 
latter  contains  more  water  and  less  albuminous 
matter  than  the  former.f  We  were  likewise 
indebted  to  Dr.  Prout  for  an  interesting  ac- 
count of  the  successive  changes  which  the 
chyle  experiences,  from  its  entrance  into  the 
lacteals,  until  it  is  finally  deposited  in  the 
thoracic  duet,  its  gradual  conversion  into 
blood  corresponding  to  the  progress  along  the 
vessels.]: 

While  the  alimentary  mass  passes  through 
the  small  intestines,  the  chyle,  as  it  is  separated 
from  it,  is  taken  up  by  the  lacteals,  so  that 
when  it  arrives  at  the  large  intestines,  nothing 
remains  but  the  residuary  matter,  whch  is  to 
be  discharged  from  the  system ;  this  consli- 

lin,  but  they  do  not  contain  much  precise  informa- 
tion ;  Ann.  Chim.  t.  lxxx.  p.  81  et  seq. 

*  Med.  Chir.  Trans,  v.  vi.  p.  618  et  seq. 

f  In  some  late  experiments  which  were  per- 
formed by  MM.  Macaire  and  F.  Marcet,  on  the 
origin  of  nitrogen  in  animals,  they  analyzed  the 
two  species  of  chyle,  and  found  them  to  be  nearly 
the  same  in  their  chemical  composition,  and  espe- 
cially in  respect  to  the  quantity  of  nitrogen  which 
they  contained  ;  Ann.  Chim.  t.  li.  p.  371. 

|  Ann.  Phil.  v.  xiii.  p.  22. .5.  See  also  Magendie, 
Physiol,  t.  ii.  p.  154.. 8. 


tutes  what  has  been  termed  the  process  of 
defecation.  There  can  be  no  doubt  that  the 
principal  and  primary  use  of  the  large  in- 
testines is  to  serve  as  a  depository  for  this 
residuary  mass,  yet  there  are  certain  circum- 
stances in  their  anatomical  and  physiological 
structure,  which  might  render  it  probable  that 
some  farther  purpose  is  served  by  them  than 
the  mere  retention  of  the  faeces.  Dr.  Prout, 
who  has  minutely  examined .  the  successive 
changes  which  the  contents  of  the  intestinal 
canal  experience,  observes  that  the  secretions 
even  of  the  rectum  still  possess  the  property 
of  coagulating  milk,  which  we  noticed  above 
as  being  one  of  the  most  distinguishing  cha- 
racters of  the  digestive  system,  so  that  it  would 
seem  that  these  organs,  in  some  way  or  other, 
still  assist  in  the  process  of  nutrition.  We 
may  presume,  however,  that  this  is  only  a 
secondary  object,  and  that  the  primary  use 
of  the  large  intestines  is  to  serve  as  a  reservoir, 
in  which  the  faecal  mass  might  be  retained, 
in  order  to  be  evacuated  at  certain  intervals 
only.*    (See  Intestinal  Canal.) 

Before  we  dismiss  this  part  of  our  subject,  it 
may  be  proper  to  make  a  few  remarks  upon 
two  of  the  abdominal  viscera,  which,  from  their 
anatomical  position  and  their  physiological  rela- 
tions, are  generally  classed  among  the  chylopoi- 
etic  organs,  as  being  supposed  to  contribute  to 
the  function  of  digestion ;  these  are  the  pancreas 
and  the  spleen.  The  pancreas  bears  a  very  near 
resemblance  to  the  salivary  glands  of  the  mouth 
and  fauces,  both  from  its  intimate  structure  and 
from  the  nature  of  its  secretions,  and  it  has  been 
presumed,  that  it  acts  in  the  same  manner  upon 
the  aliment  ;f  it  must,  however,  be  admitted 
that  we  have  little  but  analogy  or  conjecture  in 
favour  of  this  opinion. 

The  spleen  is  an  organ  which,  both  from  its 
size,  its  situation,  and  the  number  of  blood- 
vessels belonging  to  it,  has  been  supposed  to 
serve  some  important  purpose  in  the  animal 
economy,  and  from  its  apparent  connexion  with 
the  stomach  to  be,  in  some  way,  concerned  in 
the  process  of  digestion.  ^But  although  many 

*  Prout,  ut  supra,  p.  15  .  .  22  ;  see  also  Soem- 
mering, Corp.  Hum.  Fab.  t.  vi.  §  241.  We  do  not 
perceive  that  there  is  any  foundation  for  the  hy- 
pothesis of  Sir  E.  Home,  that  the  colon  is  the  organ 
in  which  the  adipose  matter  is  produced,  lect.  v.  i. 
p.  468  et  seq.  and  Phil.  Trans,  for  1821,  p.  34. 
Dr.  O'Beirne  has  lately  published  an  essay  on  the 
process  of  defamation,  to  which  we  shall  refer  our 
readers,  as  containing  some  new  views  ,on  the 
subject.  We  are  indebted  to  Berzelius  for  an  ana- 
lysis of  the  faeces,  which  appears  more  minute 
than  any  that  had  been  previously  made. 

t  For  an  account  of  the  pancreas  and  its  secre- 
tions we  may  refer  to  De  Graaf,  Tract.  Anat.  Med. 
as  the  first  correct  treatise  on  the  subject ;  to  Boer- 
haave,  Pralect.  $101,  cum  notis ;  Haller,  Prim. 
Lin.  cap.  22.  and  El.  Phys.  xxii. ;  Soemmering, 
Corp.  Hum.  Fab.  t.  vi.  p.  142.. 8;  Fordyce, 
ut  supra,  p.  70..  2;  Blumenbach,  Inst.  Physiol. 
$24:  Santorini,  tab.  13.  fig.  1.  Tiedemann  and 
Gmelin  have  given  us  the  result  of  their  examina- 
tion of  the  pancreatic  juice,  from  which  they  con- 
clude that  it  differs  in  some  respects  from  the 
saliva;  Recherches,  t.  i.  p.  41,  2.  Eeuret  and 
Lassaigne,  on  the  contrary,  suppose  these  secre- 
tions to  be  very  neaily  identical ;  Recherches, 
p,  49  et  seq. 


DIGESTION. 


21 


hypotheses  and  conjectures  have  been  formed 
on  the  subject,  there  is  none  which  seems  to 
have  obtained  any  credit  with  physiologists,  or 
indeed  to  be  entitled  to  much  consideration.* 
The  latest  researches  on  the  subject  are  those  of 
Home,  and  of  Tiedemann  and  Gmelin.  Home 
examined  the  structure  of  the  spleen,  and,  as  the 
result  of  his  investigation,  informs  us  that  it 
consists  entirely  of  a  congeries  of  bloodvessels 
and  absorbents,  and  that  there  are  interstices 
between  the  vessels  into  which  the  blood  is 
effused,  through  certain  natural  orifices  in  the 
veins,  when  they  are  much  distended.  The 
conclusion  which*  he  forms  respecting  the  use  of 
the  spleen  is,  that  it  is  a  reservoir  for  any  super- 
fluous matter,  which  may  exist  in  the  stomach, 
after  the  process  of  digestion  is  completed, 
which  is  not  carried  off  by  the  intestines,  as 
serum,  lymph,  globules, and  mucus;  that  these 
are  conveyed  to  the  spleen  by  certain  communi- 
cating vessels,  and  are  removed  from  it,  partly 
by  the  veins  and  partly  by  the  absorbents.f 

The  account  of  the  structure  of  the  spleen 
which  is  given  us  by  Tiedemann  and  Gmelin 
is  considerably  different  from  that  of  Home. 
They  inform  us  that  it  essentially  resembles 
that  of  the  lymphatic  glands,  and  they  conceive 
that  it  is  to  be  regarded  as  an  appendage  to  the 
lymphatic  system.  They  suppose  its  specific 
function  to  be  the  secretion  of  a  fluid  which  is 
conveyed  to  the  thoracic  duct,  and  being  united 
with  the  chyle,  converts  it  into  blood. \  There 
are  many  circumstances  which  render  it  pro- 
bable that  the  spleen,  in  some  way  or  other, 
promotes  sanguification,  and  we  have  some 
reason  to  believe,  that  there  is  an  immediate 
and  a  ready  communication  between  its  arterial 
and  its  absorbent  systems,  but  we  conceive 
that  the  hypothesis  must  still  be  regarded  rather 
as  a  plausible  conjecture,  than  as  a  deduction 
from  facts. 

There  is  moreover  a  circumstance  which 
must  not  be  overlooked  in  our  speculations 
respecting  the  spleen,  that  we  have  some  well 
authenticated  cases,  where  it  has  been  either 
originally  wanting,  or  has  been  removed  from 
the  body  without  apparent  injury .§  This  argu- 
ment cannot,  however,  be  considered  as  decisive, 
because  it  is  well  known,  that  in  consequence  of 
the  extraordinary  compensating  powers  of  the 
system,  certain  organs  may  be  occasionally  dis- 
pensed with,  which,  under  ordinary  circumstan- 

*  See  Haller,  El,  Phys.  lib.  xxi.  ;  Soemmering, 
t.  vi.  p.  149  et  seq. 

t  Phil.  Trans,  for  1808,  p.  45  et  seq.  and  p.  133 
et  seq.,  and  for  1821,  p.  35  et  seq.  pi.  3. .8. 

\  We  have  an  ample  and  apparently  correct  ab- 
stract of  the  memoir  of  Tiedemann  and  Gmelin  in 
the  Ed.  Med.  Jonrn  v.  xviii.  p.  285  et  seq.  See 
also  on  this  subject  Elliotson's  Physiol,  p.  108  et 
seq. ;  also  an  essay  by  Dr.  Hodgkin,  appended  to 
his  translation  of  Edwards's  physiological  work. 

$  Baillic's  Morbid  Anat.,  p.  260,  1  ;  works,  by 
Wardrop,  v.  ii.  p.  235.  [Dupuytren  observed  an  in- 
creased voracity  in  dogs  from  which  the  spleen  had 
been  removed. — Assolant,  Dissertation  du  Rate  ;  and 
Mayo  has  in  two  instances  remarked  a  considerable 
obesity  in  dogs  after  the  removal  of  the  spleen, 
but  does  not  say  whether  this  may  not  be  attribu- 
table to  the  increase  in  the  quantity  of  their  food. 
In  both  instances  the  duration  of  the  obesity  was 
for  less  than  a  year.    Mayo's  Pathol,  vol.  i. — Ed.] 


ces,  appear  the  most  essential  to  its  existence 
and  welfare.  We  may  therefore  conclude  with 
respect  to  the  pancreas  and  the  spleen,  that 
although  there  is  reason  to  suppose  that  they 
contribute,  in  some  way,  to  the  function  of  di- 
gestion, we  are  still  unable  to  ascertain  the  pre- 
cise mode  in  which  they  conduce  to  this  end. 

Before  we  dismiss  this  part  of  our  subject,  it 
will  be  necessary  to  make  a  few  observations 
upon  a  question,  which  has  been  proposed  in 
relation  to  the  digestive  process,  whether  any 
part  of  the  aliment  passes  through  the  stomach, 
and  is  taken  up  by  the  absorbents,  without  de- 
composition. It  is  obvious  that  this  cannot  be 
the  case  with  vegetable  substances  of  any  des- 
cription, and  with  respect  to  substances  of  ani- 
mal origin,  that  form  a  part  of  the  diet,  although 
they  approach  so  much  nearer  to  the  nature  of 
chyle,  yet  it  appears  that  they  are  not  entirely 
identical  with  it,  and  that  they  must  conse- 
quently be  decomposed  and  assimilated  to  the 
general  mass,  before  they  can  serve  for  the  pur- 
poses of  nutrition.  There  are  indeed  certain 
substances,  that  are  received  into  the  stomach, 
which  would  appear  to  form  exceptions  to  this 
general  principle;  these  are  the  various  saline 
substances,  which  are  found  in  all  organized 
bodies,  as  well  as  some  others,  which  give  their 
appropriate  odours  and  flavours  to  the  food,  and 
also  certain  medical  agents.  There  are  some 
salts,  which  appear  to  constitute  an  essential 
part  of  the  blood  and  other  animal  fluids,  and 
as  the  same  salts  are  introduced  into  the  sto- 
mach with  the  food,  we  may  conceive  that 
they  pass  unchanged  into  the  vessels.  There 
are  likewise  certain  substances  which  give  their 
specific  odour  to  the  milk,  and  to  other  secre- 
tions and  excretions,  proving  that  they  likewise 
pass  into  the  circulating  system  without  suffer- 
ing decomposition,  and  the  same  is  the  case 
with  some  of  the  medicaments.* 

IV.  Theory  of  digestion. — We  now  enter 
upon  the  fourth  branch  of  our  inquiry,  the  mode 
in  which  we  are  to  explain  the  action  of  the  di- 
gestive organs  upon  the  aliment.  This  has  been 
one  of  the  most  fertile  sources  of  conjecture  and 
speculation  from  the  earliest  period,  from  Hip- 
pocrates down  to  our  own  times,  and  the  ques- 
tion is  one  respecting  which  the  greatest  differ- 
ence of  opinion  still  exists  among  the  most 
intelligent  physiologists  f  We  shall  not  think 
it  necessary  to  notice  the  opinions  of  the  older 
writers,  which  were  necessarily  formed  from 
very  insufficient  data,  but  shall  select  those  hy- 
potheses which  appear  deserving  of  more  par- 
ticular attention,  either  as  having  been  supported 
by  men  of  acknowledged  eminence,    or  as 

*  See  the  remarks  of  Fordycc,  p.  122,  3  ;  the 
results  of  the  experiments  that  have  been  made  on 
this  point  are  somewhat  contradictory  ;  but  upon 
the  vvhole  there  seems  no  doubt  that,  under  certain 
circumstances,  various  extraneous  substances  may 
be  taken  up  by  the  absorbents  and  recognized  in 
the  Mood  and  other  fluids.  See  Uostock's  Physiol, 
v.  ii.  p.  569,  0,  note. 

t  For  an  account  of  the  doctrines  maintained  by 
the  earlier  physiologists,  the  reader  is  referred  to 
the  treatise  of  Fernel,  De  Concoctionibus,  Physiot. 
lib.  vi.  cap.  6  ;  Doerhaave,  Praelect.  not.  ad  j  86  ; 
llaller,  El.  Phys.  xix.  4  et  5  passim;  and  lilu- 
menbach,  Instit.  Physiol.  $360. 


22 


DIGESTION. 


possessing  in  themselves  the  merit  of  consis- 
tency and  probability.  Those  which  we  shall 
select  are  the  theories  of  trituration,  of  fermen- 
tation, of  chemical  solution,  and  of  nervous 
action,  under  one  or  other  of  which  we  may 
comprehend  all  the  most  important  speculations 
which  have  engaged  the  attention  of  modern 
physiologists. 

The  hypothesis  of  trituration  may  be  consi- 
dered as  having  originated  with  the  mechanical 
physiologists  of  the  seventeenth  century,  and 
was  apparently  supported  by  the  curious  facts, 
which  were,  at  that  time,  more  particularly 
brought  into  view  and  minutely  ascertained,  of 
the  great  force  exercised  by  the  muscular  sto- 
machs of  certain  tribes  of  birds.  The  facts, 
although  perhaps  in  some  instances  rather  ex- 
aggerated, were  sufficiently  curious,  but  the 
deductions  from  them  were  incorrect,  first,  in 
extending  the  analogy  from  one  class  of  ani- 
mals to  other  classes,  where  it  was  altogether 
inapplicable;  and  secondly,  in  conceiving  of 
the  trituration  which  takes  place  in  these  mus- 
cular stomachs,  as  constituting  the  proper  pro- 
cess of  digestion,  whereas  it  is  merely  a  preli- 
minary process,  equivalent  to  mastication.  The 
aliment,  after  it  leaves  the  gizzard,  is  in  the 
same  state  of  comminution  into  which  it  is  re- 
duced by  the  teeth  of  those  animals  that  are 
provided  with  these  organs,  and  is  then  sub- 
jected to  the  action  of  the  proper  digestive 
stomach,  and  undergoes  the  process  of  chymi- 
fication.  On  this  point  the  experiments  of 
Stevens  and  Spallanzani,  which  were  referred 
to  above,  are  quite  decisive;  they  show  clearly 
how  far  the  agency  of  mechanical  action  is  in- 
strumental in  the  process  of  digestion,  and  they 
also  show  that  some  other  principle  is  essentially 
necessary  for  its  completion.* 

While  the  mathematical  physiologists  were 
thus  attempting  to  explain  the  theory  of  diges- 
tion upon  the  principles  of  mechanical  action, 
their  rivals  the  chemists,  who  in  every  point 
strenuously  opposed  them,  brought  forward 
their  hypothesis  of  fermentation.  This  was 
originally,  at  least  in  modern  times,  advanced  by 
Vanhelmont,  and  was  embraced  by  a  large 
part  of  his  contemporaries  and  successors.! 
It  may  indeed  be  considered  as  having  been, 
for  some  time,  the  prevailing  theory  ;  a  circum- 
stance which  we  may  ascribe,  partly  to  the 
comprehensive,  or  rather  the  indeterminate 
sense  in  which  the  term  was  employed,  and 
partly  from  the  actual  phenomena  attending  the 
process,  which  were  more  easily  referable  to 
this  operation  than  to  any  other  which  was  then 
recognized. 

*  For  an  account  of  the  effects  of  trituration,  as 
given  by  some  of  the  older  physiologists,  the  rea- 
der is  more  particularly  referred  to  the  works  of 
Pitcairn,  who  was  one  of  the  most  learned  men  of 
his  time  ;  Dissert,  p,  72..95  ;  Elem.  cap,  v.  p.  25..7  ; 
see  also  Haller,  El.  Phys.  xix.  5.  1;  Hales, 
Statical  Essays,  v.  ii.  p,  174,  5;  Cheselden's  Anat. 
p.  152.. 5;  Fordyce,  ut  supra,  p.  124..  138  :  and 
Richerand,  Physiol.  *  18. 

+  See  particularly  his  singular  treatise  entitled 
"  Sextuplex  Digestio  alimenti  humani,"  where, 
together  with  much  mysticism  and  false  reasoning, 
we  find  many  acute  remarks  and  some  curious  in- 
formation. 


The  merits,  or  rather  the  truth  of  this  hypo- 
thesis rests,  in  some  degree,  upon  the  defini- 
tion of  the  term  fermentation,  or  the  mode  in 
which  it  was  employed  by  the  writers  of  that 
period.  As  far  as  we  can  understand  their 
meaning,  and  perhaps  we  may  even  say,  as  far 
as  they  themselves  attached  any  definite  idea 
to  their  own  expressions,  they  ascribed  to  this 
process  every  change  which  the  constituents  of 
the  body  undergo  by  their  action  upon  each 
other.  Fermentation  was  therefore  the  cause 
of  the  morbid  changes  which  the  system  expe- 
riences, as  well  as  of  its  natural  actions ;  it  was 
equally  the  cause  of  fever  and  inflammation,  as 
of  secretion  and  digestion ;  and  so  far  was  this 
theory  pushed,  that  even  muscular  contraction 
and  nervous  sensation  were  referred  to  certain 
fermentative  processes.  As  our  ideas  on  this 
subject  became  more  correct,  in  consequence  of 
the  extension  of  our  information,  our  language 
became  more  precise.  The  change  which  cer- 
tain vegetable  infusions  undergo  in  the  forma- 
tion of  alcohol  was  assumed  as  the  type  of  this 
class  of  actions ;  the  controversy  then  took  a 
new  aspect,  and  the  question  at  issue  was, 
whether  the  change  of  aliment  into  chyme  and 
afterwards  into  chyle  ought  to  be  referred  to 
the  same  class  of  operations  with  that  by  which 
sugar  and  mucilage  are  converted  into  alcohol. 
This  question  we  shall  be  more  able  to  answer 
satisfactorily  when  we  have  taken  a  view  of  the 
next  hypothesis,  that  of  chemical  solution. 

The  doctrine  of  chemical  solution,  as  applied 
to  the  action  of  the  stomach  upon  the  aliment 
received  into  it,  is,  in  many  respects,  very  similar 
to  that  of  fermentation,  depending,  as  will  be 
seen,  partly  upon  the  definition  of  the  terms 
employed,  and  partly  upon  the  minute  obser- 
vation of  the  various  steps  of  the  process.  The 
hypothesis  owes  its  origin  to  the  experiments  of 
Reaumur,  and  was  very  much  confirmed  by  those 
of  Stevens  and  Spallanzani,  so  often  referred 
to,  and  especially  those  of  the  latter  experimen- 
talist, where  chymification  was  produced  out  of 
the  body,  simply  by  exposing  the  various  species 
of  aliment  to  the  gastric  juice  obtained  from 
the  stomach,  in  a  proper  temperature,  and 
under  circumstances,  as  nearly  as  possible,  re- 
sembling those  of  the  natural  digestion.* 
Making  a  due  allowance  for  the  unavoidable 
causes  of  interference,  the  results  maybe  regard- 
ed as  satisfactory,  and  they  clearly  prove  one 
part  of  the  hypothesis,  that  the  vital  operation 
of  the  stomach  consists  merely  in  providing  the 
agent,  and  in  bringing  the  alimentary  substan- 
ces within  the  sphere  of  its  action.  This  con- 
clusion is  still  farther  sanctioned  by  the  power  of 
the  gastric  juice  in  suspending  or  correcting 
putrefaction,  and  in  coagulating  milk,  both 
which  properties  are  observed  in  experiments 
made  out  of  the  body,  apparently  in  as  great  a 
degree  as  in  the  stomach  itself,  and  which  can 
only  be  referred  to  the  chemical  relations  of  the 
substances  employed.  These  considerations 
must  be  allowed  to  be  very  favourable  to  the 
hypothesis  of  chemical  solution,  but  still  there 
are  many  very  serious  difficulties  which  we 
have  to  encounter,  before  we  can  regard  it  as 

*  We  may  remark  that  the  experiments  of  Dr. 
Beaumont  lead  us  to  the  same  conclusion. 


DIGESTION. 


23 


fully  established.  Of  these  the  most  Import- 
ant is  the  objection,  which  has  been  frequently 
urged  against  it,  and  has  perhaps  never  been 
satisfactorily  repelled,  that  it  is  contrary  to  the 
ordinary  operations  of  chemical  action  for  the 
same  agent  to  be  able  to  red  uce  the  various 
and  heterogeneous  matters  that  are  taken  into  the 
stomach  into  a  uniform  and  homogeneous  mass, 
and  this  difficulty  is  further  increased,  when  we 
perceive  this  powerful  effect  to  be  produced  by 
a  substance  possessed  of  properties  apparently 
so  little  active  as  the  gastric  juice.* 

These  objections,  and  others  of  an  analogous 
nature,  have  appeared  to  many  of  the  most  emi- 
nent modern  physiologists  to  press  so  powerfully 
upon  any  hypothesis  of  digestion  which  is  derived 
from  either  mechanical  or  chemical  principles, 
that  they  have  conceived  it  necessary  to  abandon 
altogether  this  mode  of  reasoning,  and  have 
referred  it  entirely  to  the  direct  action  of  what 
has  been  termed  the  vital  principle.  It  is 
assumed  that  the  internal  coat  of  the  stomach  is 
endowed  with  a  specific  property,  peculiar  to 
itself,  and  essentially  different  from  any  merely 
physical  agency,  by  which  it  acts  upon  the  food 
and  reduces  it  to  the  state  of  chyme.  This  vital 
property  of  the  stomach  is  supposed  to  be 
proved,  both  by  the  necessity  of  having  recourse 
to  this  kind  of  power,  in  consequence  of  the  in- 
adequacy of  the  ordinary  properties  of  matter, 
and  to  be  farther  confirmed  by  certain  facts  that 
have  been  supposed  to  prove  that  the  same 
substance  is  differently  affected  by  the  gastric 
juice,  merely' in  consequence  of  the  absence  or 
presence  of  this  principle.  Thus  it  has  been 
observed,  that  in  cases  of  sudden  death,  the 
stomach  itself  has  been  partially  digested  by  the 
gastric  juice  that  was  secreted  during  life,f  and 

*  Tiedemann  and  Gmclin,  as  the  result  of  their 
elaborate  experimental  researches  into  the  nature 
of  the  digestive  process,  conclude  that  it  consists 
essentially  in  the  solution  of  the  aliment  by  the 
gastric  juice.  Water  alone,  they  observe,  at  the  tem- 
perature of  the  mammalia,  is  capable  of  dissolving 
many  of  the  articles  employed  in  diet,  and'many 
•which  are  not  soluble  in  water  are  so  in  the  acids 
which  are  found  in  the  stomach,  and  to  these  they 
are  disposed  to  refer  a  considerable  part  of  the 
operation  ;  Rccherches,  t.  i.  p.  3fS3..7.  We  may, 
however,  remark,  that  a  solution  of  the  alimentary 
matters  in  water,  or  even  in  the  acids  that  exist 
in  the  stomach,  cannot  be  supposed  to  be  identical 
with  chyme. 

t  This  curious  fact,  which  was  first  announced  by 
Hunter,  Phil.  Trans,  for  1772,  p.  447  et  seq.,  and 
afterwards  more  fully  detailed  in  his  Observ.  on  the 
Anim.  CEcon.  p.  226.. .1,  has  since  been  fully  con- 
firmed by  the  observations  of  some  of  the  most  emi- 
nent modern  anatomists.  See  particularly  Baillie's 
Morb.  Anat.  ch.  7.  p.  148,  9,  and  works  by  War- 
drop,/v.  ii.  p.  136,  7,  and  engrav.  to  Morb.  Anat.  fas. 
3.  pi.  7.  fig.  2.  ;  Beck's  Med.  Jurisp.  by  Dunlop,  p. 
376. .380  contains  many  references  andgood  remarks. 
We  have  a  valuable  paper  on  the  subject  by  Br. 
Gairdner,  Ed.  Med.  Chir.  Trans,  v.  i.  p.  311  ct  seq. 
and  also  by  Br.  Carswell,  Ed.  Med.  Jour.  v.  xxxiv. 
p.  282  ct  seq.  ;  also  Archives  de  Med.  Fev.  1830, 
and  Amer.  Jour.  Med.  Sc.  v.  vii.  p.  227. .9.  In  the 
Cambridge  Phil.  Trans,  v.  i.  p.  287  etseq.,  we  have 
a  case  of  this  description  by  Br.  Haviland.  Br. 
Carswell  has  given  an  accurate  and  ample  account  of 
the  appearances  and  effects  produced  by  the  gastric 
juice  on'  the  stomach,  in  the  fifth  number  of  his 
Pathol.  Anat.  ■  it  is  accompanied  by  two  excellent 
plates. 


upon  this  principle  it  has  been  found,  that  cer- 
tain kinds  of  worms,  which  exist  in  the  diges- 
tive organs  of  animals,  are  not  affected  by  the 
gastric  juice  as  long  as  they  remain  alive,  but 
that  after  death  they  become  subject  to  its 
action. 

This  hypothesis  of  the  vital  principle  is  the 
one  which  was  supported  by  Fordyce  in  his 
elaborate  treatise,  and  is  probably  that  which, 
under  certain  modifications,  may  be  regarded  as 
the  prevailing  opinion  of  the  modern  physiolo- 
gists. To  a  certain  extent  it  is  correct,  and  the 
position  on  which  it  is  founded,  that  the  living 
body  differs  essentially  in  its  powers  and  pro- 
perties from  the  dead  body,  cannot  be  denied. 
But  it  may  still  be  questioned,  whether  the  ex- 
planation thus  offered  be  not  rather  verbal  than 
real,  or  whether  any  actual  explanation  is 
afforded  of  the  phenomena,  or  any  actual  diffi- 
culty removed  by  adopting  this  mode  of  ex- 
pression. Every  one  admits  that  a  living  sto- 
mach differs  from  one  that  is  deprived  of  life, 
but  still  it  remains  for  us  to  point  out  in  what 
this  difference  consists ;  is  it  a  chemical  or  a 
mechanical  action  ?  or  if  it  be  not  referable  to 
either  of  these  actions,  to  what  general  principle 
can  it  be  referred  ?  It  is  contrary  to  the  rules 
of  sound  reasoning  to  invent  a  new  agent  for 
the  urgency  of  the  individual  case,  until  we  are 
able  to  demonstrate  the  absolute  impossibility 
of  employing  those  which  were  previously 
recognized.  With  respect  therefore  to  the 
hypothesis  of  the  vital  principle,  as  maintained 
by  Fordyce  and  many  of  the  modern  physiolo- 
gists, we  should  say,  that  it  is  rather  a  verbal 
than  a  real  explanation  of  the  phenomena,  and 
that  it  rather  evades  the  objections  than  answers 
them. 

The  last  hypothesis  of  digestion  which  we 
proposed  to  notice,  that  of  nervous  action, 
although  somewhat  allied  to  the  one  which  we 
have  last  examined,  is  more  precise  and  defi- 
nite in  its  statement,  and  consequently  more 
entitled  to  our  consideration.  It  assumes,  that 
the  process  of  digestion  depends  upon  the 
direct  and  immediate  agency  of  the  nervous 
system.  It  is  founded  upon  the  anatomical 
fact  of  the  mode  in  which  the  stomach  is  con- 
nected with  the  nervous  system,  and  upon  the 
observed  relations  between  those  causes  that  act 
through  the  medium  of  this  system,  and  the 
changes  that  take  place  in  the  action  of  the 
stomach.  With  respect  to  the  anatomical  ar- 
gument it  has  been  urged,  that  there  is  no 
organ  of  the  body,  which  is  provided  with  such 
a  number  of  nerves,  proceeding  from  so  many 
sources,  and  connected  in  so  direct  a  way 
with  the  cerebral  system.  There  are  equally 
remarkable  circumstances  of  a  physiological 
and  pathological  nature,  which  prove  the  inti- 
mate connection  between  the  nervous  system 
and  the  action  of  the  stomach.  Not  only  does 
the  stomach  partake  of  almost  every  change 
that  occurs,  in  any  part  of  the  corporeal  frame, 
either  natural  or  morbid,  in  a  way  which  we 
must  conceive  can  only  be  brought  about 
through  the  intervention  of  the  nervous  sys- 
tem, but  it  is  affected  by  our  mental  emo- 
tions, and  that  probably  in  a  greater  degree 
than  any  other  of  our  organs,  except  tho:e  that 


24 


DIGESTION. 


are  immediately  connected  with  the  external 
senses.  Its  functions  are  excited  or  depressed 
by  various  causes,  which  can  only  act  through 
the  medium  of  the  mind  or  imagination;  while 
it  is  argued  that  in  all  cases  its  various  condi- 
tions and  the  changes  which  its  functions  expe- 
rience can  be  referred  to  no  cause,  except  to 
corresponding  changes  in  the  nervous  system.* 
This  hypothesis,  like  that  of  the  vital  prin- 
ciple, has  been  supported  by  the  consideration 
of  the  inadequacy  of  all  the  other  modes  of 
explaining  the  phenomena,  and  the  impossi- 
bility of  referring  them  either  to  mechanical 
or  to  chemical  principles.  But  it  has  this  clear 
and  decided  advantage,  that  it  rests  upon  the 
co-operation  of  an  actual  agent  of  great  and 
acknowledged  power,  one  the  existence  of 
which  is  universally  recognized,  the  only  ques- 
tion being  whether  it  is  applicable  to  this  indi- 
vidual case.  But  although  we  admit  the  facts 
in  their  full  force,  we  must  still  demur  to  the 
conclusions  that  must  be  deduced  from  them. 
If  we  inquire  upon  what  principle,  or  by  what 
medium  the  nervous  system  can  operate  on  the 
digestive  functions,  two  modes  present  them- 
selves to  the  mind.  We  may  ascribe  the 
effect  either  to  the  general  operation  of  the 
nervous  energy,  whatever  this  may  be,  which 
pervades  every  part  of  the  system,  and  the 
stomach  among  the  rest,  and  which  gives  it 
those  powers  which  distinguish  living  from 
dead  matter;  or  we  may  conceive  that  the  ner- 
vous system  is,  in  some  way,  more  especially 
concerned  in  the  production  of  the  gastric 
juice,  and  that  consequently  whatever  tends  to 
decrease  or  diminish  the  nervous  energy,  may 
operate  in  the  increased  or  diminished  produc- 
tion of  this  secretion,  and  thus  indirectly,  al- 
though necessarily,  affect  the  digestive  func- 
tion. But  although  we  may  admit  the  truth 
of  both  these  suppositions,  we  gain  no  specific 
answer  to  our  inquiry.  It  is  not  enough  to  be 
informed  that  the  stomach  acts  upon  its  con- 
tents because  it  is  alive,  or  that  whatever  pre- 
vents the  secretion  of  the  gastric  juice  puts  a 
stop  to  the  digestion.  Our  inquiry  embraces 
a  farther  object,  and  leads  us  to  investigate 
die  nature  of  the  connexion  between  these  facts 
and  the  ultimate  effect  produced,  or  to  discover 
the  reason  why  certain  acknowledged  effects 
are  connected  with  certain  acknowledged  causes; 
but  to  this  question  the  nervous  hypothesis 
gives  us  no  satisfactory  answer.  It  indeed 
rather  involves  the  theory  of  secretion  than  of 
digestion,  for  even  were  it  to  be  clearly  proved 
that  the  nervous  power  (whether,  according  to 
the  hypothesis  of  Dr.  Philip,  we  identify  it 
with  the  galvanic  influence,  or  we  act  the  more 
cautious  part  of  not  attempting  to  explain  its 
nature,)  is  the  immediate  agent  in  the  forma- 
tion of  the  secretions,  still  we  are  left  equally 

*  It  was  on  facts  of  this  description  that  Vanhel- 
mont  founded  his  hypothesis  of  the  stomach  being 
the  immediate  seat  of  the  soul  ;  Orlus  Med.  p. 
248,  49,  50.  See  also  on  the  same  subject  the 
remarks  of  Hartley,  on  Man,  v.  i.  p.  189,  and 
Soemmering,  §  179.. .4,  who  may  be  respectively 
considered  as  among  the  most  accurate  metaphysi- 
cians and  anatomists  of  modern  times. 


uninformed  concerning  the  mode  in  which  this 
fluid,  when  secreted,  performs  its  appropriate 
function.* 

From  this  brief  review  of  the  different  the- 
ories of  digestion  we  may  conclude,  that  the 
hypothesis  of  trituration  is  decidedly  incorrect, 
and  that  those  of  the  vital  principle  and  the 
nervous  energy  do  not  resolve  the  question. 
We  are  therefore  reduced  to  the  two  chemical 
hypotheses,  which,  although  not  without  con- 
siderable difficulties,  are  not  so  palpably  defec- 
tive or  erroneous.  In  deciding  between  these 
two  hypotheses  it  must  be  our  first  object  to 
ascertain  the  exact  sense  in  which  the  term 
fermentation  was  used  by  the  older  physio- 
logists, and  how  far,  according  to  the  modern 
use  of  the  term,  it  is  applicable  to  the  phe- 
nomena in  question.  The  word  was  originally 
employed  in  a  very  extensive,  and,  as  may  be 
supposed,  in  a  somewhat  vague  manner,  to 
designate  every  spontaneous  change  which  took 
place  between  bodies  that  were  placed  in  con- 
tact, and  which  generally  manifested  itself  by 
the  extrication  of  some  gaseous  or  volatile 
matter.  Thus  all  the  spontaneous  changes  in 
the  body,  whether  natural  or  morbid,  were 
considered  to  be  different  kinds  of  fermen- 
tations, and  many  of  the  changes  that  take 
place  among  inorganic  substances,  as  well  as 
various  processes  in  the  laboratory,  were  dis- 
tinguished by  the  same  appellation. 

As  our  knowledge  of  the  nature  of  these 
processes  was  extended,  and  we  were  thus 
enabled  to  ascertain  more  correctly  what  was 
the  change  which  was  produced,  our  language 
became  more  correct  and  better  defined,  and 
the  term  fermentation  was  restricted  to  a  spe- 
cific operation,  in  which  certain  proximate 
principles,  derived  from  organized  bodies,!  act 
upon  each  other,  and  enter  into  new  elementary 
combinations.  The  process  is  generally  pro- 
moted by  the  addition  of  a  substance  called 
the  ferment,  which  is  employed  to  enable  the 
bodies  to  act  upon  each  in  the  first  instance, 
although,  when  the  action  has  commenced,  its 
presence  may  be  no  longer  necessary.  The 
most  familiar  kind  of  fermentation  is  that  by 
which  a  mixture  of  sugar  and  mucilage  is  con- 
verted into  alcohol,  and  that  by  which  the 
same  substances,  when  exposed  to  the  atmos- 
phere, and  to  a  certain  temperature,  are  con- 
verted into  acetous  acid.  How  far  we  are  to 
extend  the  number  of  fermentations  is  a  point 
respecting  which  chemists  are  not  agreed,  and 
indeed  there  appears  to  be  no  reason  but  that 
of  convenience  which  can  decide  the  point. 
We  accordingly  find  that  while  Mr.  Brande  is 
disposed  to  restrict  the  term  to  the  vinous  and 
acetous  fermentation,^  others  extend  it  to  three, 
four,  or  with  Dumas, §  even  to  six  processes. 

*  We  may  refer  our  readers  to  the  judicious  re- 
marks of  Dr.  Prichard,  in  his  Essay  on  the  Vital 
Prin.  sect.  8. 

t  Some  of  the  most  eminent  chemists  confine  the 
process  of  fermentation  to  the  proximate  principles 
derived  from  vegetables  ;  but  this  restriction  is  Dot 
universally  adopted,  nor  does  it  appear  to  be  neces- 
sary. 

i  Ut supra. 

§  Ut  supra. 


DIGESTION. 


25 


Among  these,  one  which  is  the  subject  of  daily 
observation  is  the  panary,  or  that  by  which 
dough  is  converted  into  bread,  a  change  which 
appears  to  come  strictly  under  the  definition, 
as  a  spontaneous  action  among  the  elementary 
constituents  of  the  body,  by  which  a  substance 
is  produced,  essentially  different  from  the  one 
from  which  it  was  composed.  Now  we  are 
disposed  to  think  that  the  same  principle  will 
apply  to  the  conversion  of  aliment  into  chyme, 
and  that  it  is  little  more  than  a  difference  in 
the  mode  of  expression,  whether  we  say  that 
digestion  depends  upon  chemical  action  gene- 
rally, or  upon  that  peculiar  kind  of  chemical 
action  which  has  been  termed  fermentation. 

The  foregoing  remarks  apply  immediately  to 
the  production  of  chyme,  and  it  still  remains 
for  us  to  consider  whether  the  same  mode  of 
reasoning  can  be  applied  to  the  further  conver- 
sion of  chyme  into  chyle.  And  it  must  be 
confessed  that  this  part  of  our  subject  presents 
us  with  new  difficulties,  and  that  the  analogy, 
which  in  the  former  case  was  imperfect,  is 
apparently  still  more  so,  when  we  apply  it  to  . 
the  action  of  cliylification.  Here  we  have  a 
chemical  change  in  the  constituents,  without 
the  intervention  of  any  assignable  agent,  at- 
tended with  the  production  of  a  new  substance, 
in  consequence,  as  far  as  we  can  judge,  of  the 
spontaneous  action  of  the  elements  upon  each 
other,  and  with  the  separation  of  the  substance 
thus  formed  from  the  remainder  of  the  mass. 
But  although  the  operation  may  be  somewhat 
more  complicated,  and  although  we  may  find 
it  less  easy  to  assign  an  efficient  cause  for  each 
step  of  the  process,  there  will  be  found  nothing 
contrary  to  the  recognized  effects  of  chemical 
affinity.  And  with  respect  to  the  question, 
how  far  these  effects  should  be  referred  to  the 
specific  action  of  fermentation,  we  may  remark 
that  the  result  of  the  proper  fermentative  pro- 
cesses is  to  form  a  new  product,  and  to  sepa- 
rate the  product  thus  formed  from  the  residuary 
mass.  Upon  the  whole  therefore  we  may  con- 
clude, that  although  there  are  many  points  in 
the  chemical  theory  of  digestion  that  are  still 
unexplained  and  require  to  be  further  investi- 
gated, yet  that  we  have  no  facts  which  directly 
oppose  it,  while  -the  difficulties  which  we  feel 
on  certain  points  would  appear  to  be  princi- 
pally owing  to  the  imperfect  state  of  our  know- 
ledge on  the  subject. 

V.  Peculiar  affections  of  the  digestive  or- 
gans.— We  now  proceed,  in  the  last  place,  to 
offer  some  remarks  on  certain  affections  of  the 
stomach  and  its  appendages,  which  are  only 
indirectly  connected  with  the  function  of  diges- 
tion. Of  these  the  most  important  are  hunger, 
thirst,  and  nausea;  we  shall  consider  in  suc- 
cession the  causes  of  each  of  them,  and  the 
relation  which  they  bear  to  the  animal  economy 
in  general. 

Hunger  is  a  peculiar  perception  experienced 
in  the  stomach,  depending  on  the  want  of 
food.  Its  final  cause  is  obvious,  but  respecting 
its  efficient  cause  there  has  been  considerable 
difference  of  opinion  among  physiologists, 
some  referring  it  to  a  mechanical,  others  to  a 
chemical  action,  while  by  a  third  set  of  writers 


it  is  referred  exclusively  to  a  peculiar  condition 
of  the  nervous  system.  Before  we  enter  into 
the  respective  merits  of  these  opinions  it  will 
be  necessary  to  remark  concerning  the  feeling 
excited  by  hunger,  that  it  is  one  of  a  specific 
nature,  as  essentially  different  from  the  mere 
perception  of  touch,  as  the  sense  of  sight  is 
from  that  of  mechanical  pressure  made  on  the 
ball  of  the  eye.  In  physiological  language 
the  stomach  may  be  regarded  as  one  of  the 
organs  of  sense,  in  the  same  way  with  the  eye 
and  the  ear;  i.  e.  a  part  furnished  with  a  spe- 
cific apparatus  for  producing  specific  impres- 
sions on  a  set  of  nerves  appropriated  to  it, 
which  convey  to  the  mind  certain  perceptions, 
and  which,  by  habit  or  by  instinct,  we  connect 
with  certain  conditions  of  the  organ.  In  most 
cases  we  are  able  to  point  out  distinctly  the 
nature  of  the  agent  which  produces  these  per- 
ceptions, as  light  when  applied  to  the  eye,  and 
the  undulations  of  the  air  to  the  ear ;  in  the 
particular  case  of  the  stomach  we  are  not  able 
to  point  out  any  corresponding  agent  of  this 
description,  and  in  so  far  the  analogy  between 
the  stomach  and  the  organs  of  sense  must  be 
considered  as  defective. 

The  mechanical  physiologists  ascribed  hun- 
ger to  the  friction  of  the  different  parts  of  the 
internal  membrane  of  the  stomach  on  each 
other,  an  opinion  which,  although  sanctioned 
to  a  certain  extent  by  Haller,*  must  be  aban- 
doned, whether  we  regard  the  anatomical 
structure  of  the  part,  which  shows  that  such 
friction  is  incompatible  with  its  rounded  form, 
and  the  disposition  of  its  muscular  fibres,  or 
the  nature  of  the  sensation  itself,  which  is 
specifically  different  from  that  produced  by 
pressure,  or  any  species  of  mechanical  impulse 
on  the  surface  of  the  body.  Nor  can  the  hy- 
pothesis be  maintained,  which  supposes  that 
the  action  of  the  gastric  juice,  by  its  tendency 
to  decompose  organized  substances,  exercises 
a  degree  of  this  eroding  quality  on  the  internal 
coat  of  the  stomach,  and  thus  produces  the 
uneasy  sensation.  But  in  this  hypothesis  the 
great  distinction,  which  has  been  so  frequently 
referred  to,  between  living  and  dead  matter  as 
to  the  action  of  the  gastric  juice  is  disregarded; 
besides  that  from  every  analogy  which  we  pos- 
sess, it  might  be  presumed  that  a  substance  so 
mild  and  apparently  so  little  active  as  the  gas- 
tric juice,  could  not  produce  effects,  which 
must  be  attributed  to  a  body  possessed  of  highly 
acid  or  noxious  qualities.  And  it  may  be  fur- 
ther remarked,  that  in  cases  of  the  most  pro- 
tracted privation  of  food,  and  where  death  has 
occurred  after  the  most  severe  pangs  of  hunger, 
nothing  like  erosion  of  the  stomach  has  been 
observed,  and  that  conversely,  in  those  in- 
stances where  this  effect  has  been  produced 
after  death,  we  have  no  reason  to  suppose  that 
it  was  in  any  degree  caused  by  the  deficiency 
of  food,  or  had  been  preceded  by  hunger. 

From  what  has  been  stated  above  it  may  be 
inferred  that  the  view  which  we  feel  disposed 
to  take  of  the  efficient  cause  of  hunger  is  to 
regard  it  as  a  specific  perception,  occasioned 

*  Prim.  Lin.  §  36'8  ;  El.  Phys.  xix.  2,  12. 


26 


DIGESTION. 


by  a  peculiar  state  induced  on  certain  of  the 
nerves  of  the  stomach,  in  the  same  way  that 
certain  nerves  of  the  eye  and  of  the  ear  receive 
the  impressions  of  light  and  of  sound.  There 
is,  however,  this  difference  between  the  two 
cases,  that  in  the  instance  of  the  eye  and  the 
ear  we  are  able  to  point  out  the  agent  by  which 
the  impression  is  made,  whereas  we  are  unable 
to  do  this  with  respect  to  the  stomach.* 

The  perception  of  thirst,  although  seated  in 
the  tongue  and  fauces,  is  so  intimately  con- 
nected with  the  state  of  the  stomach,  as  to  be 
properly  referred  to  our  consideration  in  this 
place.  It  is  immediately  produced  by  a  defi- 
ciency of  the  mucous  secretion  of  the  part, 
and  consequently  must  be  regarded  as  ulti- 
mately depending  on  a  peculiar  condition  of 
the  glands  which  secrete  this  substance.  Al- 
though the  sensation  of  thirst  has  a  less  specific 
character  than  that  of  hunger,  yet  we  conceive 
that  it  must  be  referred  to  a  peculiar  action 
induced  upon  the  nerves  of  the  part,  in  a  way 
analogous  to  what  we  suppose  to  take  place 
with  respect  to  hunger,  and  like  it  depending 
on  a  peculiar  action,  the  intimate  nature  of 
which  we  are  unable  to  explain.f 

There  are  various  circumstances,  which  differ 
much  in  their  nature  and  origin,  acting  upon 
different  parts  of  the  system,  which  all  concur 
in  producing  a  peculiar  sensation  termed  nausea, 
which  is  referred  to  the  region  of  the  stomach. 
It  is  usually  attended  with  a  considerable 
derangement  of  all  the  powers  of  the  body, 
both  muscular  and  nervous,  and  if  continued, 
produces  the  effort  to  vomit.  The  act  of  vomit- 
ing consists  in  an  inversion  of  the  peristaltic 
motion  of  the  stomach,  commencing  at  the 
pylorus,  which  causes  the  contents  to  be  carried 
towards  the  cardia,  and  to  be  forcibly  ejected 
from  the  oesophagus.  It  has  been  generally 
supposed  that  the  impression  which  produces 
nausea,  and  ultimately  vomiting,  is  in  the  first 
instance  made  on  the  nerves  of  the  stomach, 
that  it  is  communicated  by  them  to  its  muscu- 
lar fibres,  that  their  action  is  transmitted, 
probably  by  the  intervention  of  the  nerves,  to 
the  muscles  of  the  abdomen  and  to  the  dia- 
phragm, and  that  their  contraction  cooperates 
with  the  muscular  coats  of  the  stomach  in  the 
evacuation  of  its  contents.  It  has  long  been  a 
subject  of  controversy  among  physiologists  in 
what  degree  the  abdominal  muscles  assist  the 
coats  of  the  stomach,  or  how  far  the  latter  are 

*  See  the  remarks  of  Blumenbach,  ut  supra, 
§  21 ;  Magendie,  Physiol,  t.  ii.  p.  24  et  seq.  and 
art.  "  Digestion,"  in  Diet.  Sc.  Med.  t.  ix.  p.  370.. 5. 
We  have  some  valuable  observations  by  Boerhaave, 
Praclect.  §  88.  cum  notis ;  also  by  Soemmering, 
Corp.  Hum.  Fab.  t.  vi.  §  149. .56.  Haller  describes 
the  phenomena  of  long-continued  fasting  with  his 
usual  minute  correctness;  El  Phys.  xix.  2,  3.. 7; 
we  have  some  interesting  cases  of  long-protracted 
abstinence  in  Dr.  Copland's  Trans,  of  Richerand's 
Physiol,  p.  565  et  seq. 

t  For  an  account  of  the  phenomena  of  thirst, 
and  the  explanations  that  have  been  offered  of 
them,  the  reader  is  referred  to  Boerhaave,  Praelect. 
§585,  804;  Haller,  Prim.  Lin.  $  639  ;  El.  Phys. 
xix.  2,  9 ;  Blumenbach,  Physiol.  §  330-2,  cum 
nota  B;  Magendie,  Physiol,  t.  ii.  p.  31. .3;  Elliot- 
son's  Physiol,  p.  52. 


competent  to  produce  the  effect  without  the 
aid  of  the  former.  Haller  supposed  that  the 
stomach  alone  is  capable  of  evacuating  its 
contents,*  while  Chirac,  Duverney,f  and  other 
French  physiologists  conceived  that  this  organ 
is  entirely  passive  in  the  act  of  vomiting,  and 
the  same  opinion  has  been  lately  maintained 
by  Magendie,  and  supported  by  a  series  of 
direct  experiments.  He  not  only  found  that 
vomiting  was  entirely  suspended,  when  the 
abdominal  muscles  and  diaphragm  were  ren- 
dered incapable  of  acting  upon  the  stomach, 
but  he  even  informs  us,  that  when  the  stomach 
was  removed,  and  a  bladder  substituted  in  its 
place,  vomiting  was  still  induced.]: 

But  we  are  still  disposed  to  believe  that  the 
commonly  received  doctrine  is  the  correct  one; 
that  the  action  commences  in  the  muscular 
fibres  of  the  stomach,  and  is  materially  assisted 
by  the  diaphragm  and  abdominal  muscles. 
We  rest  our  opinion  on  the  analogy  of  the 
other  hollow  viscera,  the  uterus,  the  bladder, 
and  the  intestines,  where  the  contraction 
commences  in  the  organ  itself ;  on  the  ante- 
cedent probability,  that  as  the  agent  which 
produces  the  effect  is,  in  most  cases,  applied 
to  the  stomach,  it  must  be  supposed  to  act 
immediately  upon  it,  and  lastly  on  the  mecha- 
nical nature  of  the  act  of  vomiting,  which 
appears  to  be  produced  rather  by  a  sudden 
and  forcible  contraction  of  the  organ  itself, 
than  by  any  external  pressure  exercised  upon 
it.  We  conceive  also  that  this  view  of  the 
subject  is  confirmed  by  the  effect  that  succeeds 
to  the  division  of  the  par  vagum ;  it  is  asserted 
that  when  this  nerve  is  divided  vomiting  can 
no  longer  take  place,  and  as  it  is  distributed 
principally  over  the  stomach,  so  as  to  make  it 
appear  that  this  organ  is  its  specific  destination, 
we  may  presume  that  the  incapacity  for  vomit- 
ing depends  upon  the  loss  of  power  in  the 
stomach.  § 

*  El  Phys.  xix.  4.  12,  14 ;  see  also  Lieutaud, 
Mem.  Acad,  pour  1752,  p.  223  et  seq. ;  Sauvages, 
Nosol.  Meth.  t.  ii.  p.  337. 

t  Miscel.  Curios.  Dec.  ii.  ant.  4,  obs.  125,  p. 
247,  8,  and  Mem.  Acad,  pour  1700,  hist.  p.  27. 
Nearly  the  same  opinion  was  maintained  by  Hun- 
ter, Anim.  CEcon.  p.  199,  0. 

|  Mem.  sur  le  vomissctnent,  "p.  19,  2,  and 
Physiol,  t.  ii.  p.  138.. 40. 

S  Bell's  Anat.  vol.  iv.  p.  54  et  seq.  Legallois  and 
Beclard  performed  a  series  of  experiments  on  this 
subject,  which  consisted  in  injecting  into  the  veins 
a  solution  of  emetic  tartar.  They  particularly 
attended  to  the  effect  produced  on  the  oesophagus, 
the  diaphragm,  the  abdominal  muscles,  and  the 
stomach  itself;  the  conclusion  which  may  be  de- 
duced from  these  experiments  is,  that  vomiting 
cannot  take  place  without  the  compression  of  some 
of  the  contiguous  parts  upon  the  stomach  ;  CEuvres 
de  Legallois,  t.  ii.  p.  91  et  seq.  Dr.  Hall  has  lately 
investigated  the  nature  of  the  connexion  between 
the  act  of  vomiting  and  the  state  of  the  organs  of 
respiration.  He  conceives  that  the  diaphragm  is 
passive  in  the  operation  and  that  the  larynx  is 
closed,  and  he  hence  concludes  that  the  muscles 
of  expiration,  by  their  sudden  contraction,  press 
upon  the  stomach  and  project  its  contents  through 
the  oesophagus  ;  Quart.  Journ.  We  must  conceive, 
however,  that  a  slate  of  nausea  must  be,  in  the 
first  instance,  induced,  and  this  must  take  place 
through  the  intervention  of  the  nerves  of  the 


DIGESTIVE  CANAL. 


27 


With  respect  to  the  causes  of  nausea  they 
may  be  reduced  to  two  heads ;  those  that  act 
immediately  on  the  stomach,  and  those  that 
act,  in  the  first  instance,  on  the  system  at  large. 
Of  the  first  class  the  most  active  in  their  opera- 
tion are  the  medicinal  substances  which  are 
specifically  styled  emetics,  from  their  peculiar 
tendency  to  produce  nausea  and  subsequent 
vomiting.  Besides  these  certain  kinds  of  food, 
or  food  of  any  description,  if  it  remain  in  an 
undigested  state,  and  various  substances  of  an 
acrid  or  stimulating  nature  frequently  produce 
nausea  and  vomiting.  In  the  second  class  of 
causes  we  have  to  enumerate  various  circum- 
stances, which  act  .upon  parts  of  the  body, 
sometimes  very  remote  from  the  stomach,  but 
which,  either  by  direct  nervous  communica- 
tion, by  sympathy,  or  association,  produce  the 
effect  in  question.  One  of  the  most  powerful 
of  these  is  the  motion  of  a  vessel  at  sea,  giving 
rise  to  the  well-known  and  most  distressing 
sensation  of  sea-sickness,  certain  morbid  affec- 
tions of  the  brain,  particular  odours  and  flavours, 
renal  and  biliary  calculi,  herniae  or  other  affec- 
tions of  the  intestinal  canal,  and  lastly,  certain 
causes  which  can  act  only  through  the  medium 
of  the  mind  or  imagination.  These  various 
circumstances,  although  so  extremely  different 
in  their  nature  and  origin,  agree  in  producing 
a  similar  effect  on  the  stomach,  which  may  be 
explained  by  referring  to  the  nervous  com- 
munications which  exist  between  the  organ 
and  every  part  of  the  system,  and  more  espe- 
cially with  the  other  abdominal  viscera  and  the 
brain.* 

Bibliography.  —  Acad,  del  Cimento,  Esper. 
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Baglivi,  Opera,  Lugd.  1704.  Baillie's  Morbid  Anat. 
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stomach.  See  also  the  art.  "  Vomissement,"  by 
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*  Haller,  Prim.  Lin.  §  652,  and  El.  Phys.  xix. 
4,  13;  Soemmering,  Corp.  Hum.  Fab.  t.  iv.  §  178; 
Magendie,  ut  supra. 


digestion,  (2d  ed. )  Lond.  1791.  Fox  on  the  teeth, 
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1767.  Hall,  in  Quart.  Journ.  Hartley  on  man, 
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from  North  America.  Home's  Lectures  on  compa- 
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spect.  Physiol.  Kellie,  in  Brewster's  Encyc. 
Legallois,  CEuvres  de,  Par.  1624.  Leuret  <Sp  Las- 
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1781.  Lower,  De  corde,  Amst.  1669.  Macaire 
F.  Marcet,  in  Ann.  Chim.  t.  ii.  Magendie,  in  Ann. 
Chim.  et  Phys.  t.  iii.  Magendie,  in  Diet.  Sc.  Med. 
t.  ix.  Ditto,  Sur  le  Vomissement,  Par.  1813. 
Marcet,  in  Med.  Chir.  Tr.  vol.  vi.  M'Bride's 
Essays  (2d  ed.)  Lond.  1767.  Montegre,  Exper. 
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in  Ed.  Med.  Essays,  vol.  iv.  Monro  ( Tert.)  on 
the  gullet,  Edin.  1811.  O'Beirne  on  defaecation, 
Dub.  1833.  Paris  on  diet,  Lond.  1826.  Parr's 
Med.  Diet.  Lond.  1809.  Pearson's  Synopsis,  Lond. 
1808.  Peyer,  Anat.  Ventric.,  in  Manget,  Bibl. 
anat.  Peyer,  Mericologia,  Basil.  1685.  Philip's 
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principle,  Lond.  1829.  Pringle's  Observations, 
(3d  ed.)  Lond.  1761.  Proui's  Abstract  of  his 
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xiv.  Ditto,  in  Phil.  Trans,  for  1824.  Ray's 
Wisdom  of  God,  Lond.  1717.  Reaumur,  in  Mem. 
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(J.  Bostock.) 

DIGESTIVE  CANAL  (Comp.  Anat.)  — 
The  digestive  canal  is  that  cavity  of  the  body 
which  is  destined  to  receive  the  food  of  animals 
and  to  retain  it  until  its  nutritious  part  has  been 
separated  or  absorbed.  It  is  termed  also  the 
alimentary  or  the  intestinal  canal.  As  it  is  the 
part  into  which  foreign  matter  is  first  conveyed 
for  the  nutriment  of  the  system,  its  forms  and 
structure  are  most  intimately  related  to  the  kind 
of  food,  and  consequently  to  the  living  habits 
and  instincts,  ard  the  whole  mechanism  of 
animals.  The  most  universal  organs  in  the 
animal  kingdom  are  the  digestive,  and  most  of 
the  others  may  be  considered  as  secondary  or 
subservient  to  these.  The  lowest  animals  pre- 
sent us  with  no  other  organs  than  those  sub- 
servient to  digestion,  and  almost  all  the  organs 


28 


DIGESTIVE  CANAL. 


which  are  superadded  to  these  as  we  ascend  in 
the  scale  either  form  an  extension  of  the  nutri- 
tive apparatus,  or  are  destined  to  regulate  the 
kind  of  food  admitted  into  the  alimentary 
cavity.  An  animal,  in  the  abstract,  may  almost 
be  viewed  as  a  moving  sac,  organized  to  con- 
vert foreign  matter  into  its  own  likeness,  and 
all  the  complex  organs  of  animal  life  are  but 
auxiliaries  to  this  primitive  digestive  bag.  The 
bones  and  other  hard  parts  which  form  the 
solid  frame-work  of  the  body  connected  toge- 
ther by  their  various  ligaments  serve  only  as 
firm  levers  to  enable  the  active  organs,  the 
muscles,  to  carry  it  to  and  fro,  and  the  ner- 
vous system  with  its  various  organs  of  sense 
serve  but  to  direct  its  motions  in  quest  of  food. 
Nature  has  placed  the  unorganized  food  of 
plants  on  the  exterior  of  their  body,  and  their 
vessels  are  sent  there  to  seek  it,  which  roots 
them  through  life  to  a  fixed  point;  but  animals 
place  their  food  in  their  stomach  and  have  their 
roots  directed  inwards  and  towards  that  central 
reservoir,  so  that  they  can  move  about  and 
select  what  is  most  congenial  to  their  nature. 
The  organs  of  animal  life  relate  to  this  diffe- 
rence between  the  two  organized  kingdoms — 
to  this  locomotion  of  animals  and  their  power 
of  selecting  their  food;  but  the  organs  of  vege- 
tative life  of  which  the  alimentary  canal  is  the 
first,  relate  merely  to  the  assimilation  of  food 
when  already  within  the  body,  and  are  there- 
fore common  to  animals  with  plants.  The 
digestive  surface  of  the  plant  is  the  surface  of 
its  root,  ramified  and  fixed  in  the  soil,  which 
affords  it  a  never-failing  supply  of  food;  so 
that  the  vegetable  is  like  an  animal  with  its 
stomach  turned  inside  out.  The  organs  of 
relation  are  necessarily  connected  with  the 
varied  circumstances  in  which  animals  are 
placed,  and  are  remarkable  for  their  variable 
character,  and  even  for  their  inconstancy  in  the 
lower  tribes,  where  they  are  often  entirely  want- 
ing; but  those  of  vegetative  or  organic  life  are 
more  regular  and  constant  in  their  character, 
and  indeed  no  organ  is  more  universal  among 
animals  than  that  internal  digestive  cavity  by 
which  they  differ  so  much  from  the  species  of 
the  vegetable  kingdom.  This  primitive  sac  is 
but  a  development  or  a  continuation  of  the 
mucous  surface  of  the  skin,  which  extends 
into  the  homogeneous  cellular  tissue  of  the 
body,  or  completely  through  it ;  and  although, 
in  the  simplest  conditions  of  animals,  it  per- 
forms alone  all  the  assimilative  functions,  we 
find  it,  as  we  ascend  in  the  scale,  giving  origin 
to  various  other  systems  to  which  distinct  parts 
of  the  complex  function  of  assimilation  are 
entrusted.  Thus  the  peripheral  mode  of  nutri- 
tion of  the  plant  passes  insensibly  into  the 
central  internal  mode  of  the  animal,  and  all 
the  organs  of  organic  life,  whether  they  open 
into  the  digestive  cavity  within,  or  on  the 
surface  of  the  body  without,  may  be  considered 
as  originating  from  the  skin,  which  is  itself  only 
a  portion  of  the  primitive  cellular  tissue  of  the 
body,  here  modified  by  the  contact  of  the  sur- 
rounding element  so  as  to  assume  the  character 
of  a  mucous  membrane.  As  the  various  tubular 
prolongations  become  more  and  more  developed 


and  isolated  from  this  primitive  source,  they 
assume  properties  more  and  more  peculiar, 
and  thus  form  the  numerous  glandular  appara- 
tus and  vascular  systems. 

An  internal  digestive  cavity,  the  first  element 
of  all  the  organs  subservient  to  individual 
nutrition,  is  observed  in  every  class  of  animals 
and  almost  in  every  genus ;  and  where  this  part 
has  not  yet  been  perceived,  there  can  be  little 
doubt,  from  analogy,  of  its  existence.  Its 
form  and  structure  vary  according  to  the  kind 
of  food  on  which  the  various  tribes  of  animals 
are  destined  to  subsist,  and  the  extent  of  elabo- 
ration it  requires  to  undergo  to  assimilate  it  to 
the  animal's  body ;  so  that  the  diversities  of 
this  first  part  of  the  digestive  apparatus  are 
intimately  related  to  all  the  living  habits  of 
animals,  and  to  all  the  peculiarities  they  pre- 
sent in  their  other  assimilative  organs  and  in 
their  organs  of  relation. 

1.  Polj/gastrica.  In  the  monads  a  digestive 
apparatus  is  distinctly  seen,  and  in  almost  all 
the  other  genera  of  animalcules,  where,  indeed, 
the  internal  cavities  connected  with  this  im- 
portant function  are  so  numerous  in  almost  all 
the  known  forms  of  these  animals  that  this 
lowest  class  of  animals  has  been  termed  poly- 
gastrica  to  express  their  common  character. 
From  the  transparency  of  these  minute  animals, 
their  digestive  sacs  appear,  when  empty  or 
when  filled  with  water,  like  portions  of  the 
common  cellular  substance  of  the  body,  or 
like  animalcules  which  have  been  swallowed, 
or  like  internal  gemmules ;  and  from  not  being 
generally  recognized  as  alimentary  cavities, 
many  observers  were  led  to  suppose  that  the 
animalcules  are  nourished  solely  by  superficial 
absorption  like  marine  plants.  Leuwenhoeck, 
however,  not  doubting  that  they  possessed  a  sto- 
mach, believed  that  they  devour  each  other;  this 
was  observed  also  by  Ellis,  and  Spallanzani  main- 
tained that  they  devour  each  other  so  voraciously 
that  they  are  seen  to  become  distended  with 
this  food.  Goeze  saw  the  trichoda  seizing  and 
swallowing  the  animalcules  which  were  smaller 
than  itself.  Baron  Gleichen,  in  order  to  dis- 
cover the  form  of  their  internal  digestive  cavi- 
ties, placed  them  in  infusions  coloured  with 
carmine  which  they  soon  swallowed,  and  in 
his  coloured  plates  he  has  represented  this  red 
colouring  matter  as  filling  the  internal  stomachs 
of  numerous  tricliodte,  vorticella;,  and  other 
animalcules.  Indeed  those  internal  globular 
cavities  of  animalcules  are  represented  in  the 
plates  of  Miiller,  Bruguiere,  and  all  the  older 
writers  on  this  class.  But  Ehrenberg,  by 
adopting  the  plan  of  Gleichen  and  Trembley 
of  employing  opaque  colouring  matter  to  detect 
the  forms  of  these  internal  cavities,  and  by 
using  principally  carmine,  sap-green,  and  indigo, 
carefully  freed  from  all  impurities  which  might 
prevent  their  being  swallowed,  has  succeeded 
better  than  all  his  predecessors  in  unfolding 
the  structure  of  the  digestive  organs  of  animal- 
cules. Such  coloured  organic  matter  diffused 
as  fine  particles  mechanically  suspended  in  the 
water  in  which  animalcules  are  placed,  is 
readily  swallowed  by  them,  and  renders  visible 
through  their  transparent  bodies  the  form  and 


DIGESTIVE  CANAL. 


29 


disposition  of  their  alimentary  cavities;  but 
however  long  they  remain  in  these  coloured 
infusions,  with  their  stomachs  distended  with 
the  colouring  matter,  it  is  not  perceived  to 
communicate  the  slightest  tinge  to  the  general 
cellular  tissue  of  their  body.  In  most  of  the 
animals  of  this  class  there  is  an  alimentary 
canal  with  an  oral  and  an  anal  orifice,  which 
traverses  the  body  and  is  provided  with  nume- 
rous small  round  coecal  appendices,  which  open 
into  its  sides  throughout  its  whole  course,  and 
which  appear  to  perform  the  office  of  stomachs 
in  receiving  and  preparing  the  food.  In  the 
simplest  forms  of  animalcules  however,  (as  in 
the  monas  atomus  represented  in  fig.  4  A)  there 


is  but  one  orifice  {fig.  4  A,  a)  to  the  alimen- 
tary cavity,  and  the  numerous  coecal  appendices 
(fig.  4  A,  b)  open  into  this  general  wide  orifice 
placed  at  the  anterior  extremity  of  the  body. 
This  simpler  form  of  the  digestive  apparatus 
is  found  in  the  monads  and  in  about  forty  other 
known  genera  of  polygastrica,  which,  from 
this  circumstance  of  their  having  no  intestine 
passing  through  their  body,  have  been  grouped 
together  as  an  order  under  the  name  of  anen- 
tera.  In  the  ?nonas  termo,  which  is  only 
about  the  two-thousandth  of  a  line  in  diameter, 
four  and  even  six  of  these  roand  stomachs  have 
been  seen  filled  with  the  colouring  matter, 
although  they  did  not  appear  to  be  half  the 
number  which  might  be  contained  in  its  body. 
Each  of  these  round  stomachs  was  about  ^  of 
a  line  in  diameter,  and  they  appear  to  open, 
as  in  other  ane.ntcra,  by  a  narrow  neck  into  a 
wide  funnel-shaped  mouth  surrounded  with  a 
single  row  of  long  vibratile  cilia,  which  attract 
the  floating  organic  particles  or  minuter  invisi- 
ble animalcules  as  food.  This  anenterous  form 
of  the  digestive  sacs  is  found  both  in  the  lori- 
cated  and  in  the  naked  kinds  of  animalcules 
belonging  to  the  lowest  genera  of  the  class, 
many  of  which,  however,  have  been  found  to 
be  only  the  young  of  supposed  higher  genera. 

The  intestine  which  traverses  the  interior  of 
the  body  in  all  the  higher  forms  of  polygastric 
animalcules,  and  connects  all  the  internal  sto- 
machs with  its  cavity,  presents  very  different 
appearances  in  different  genera  and  even  in 
different  species  of  the  same  genus.  In  the 
vorticellu  citrina  (fig.  4  13)  the  intestine  (fig. 
4  B,  b,  c)  passes  downwards  from  the  mouth, 
nearly  of  equal  width  throughout,  and  after 
forming  a  curve  in  the  lower  part  of  the  body, 
it  ascends  to  terminate  at  the  same  oral  funnel- 
shaped  ciliated  aperture,  (fig-^  B,  a,)  between 


the  two  circles  of  cilia  around  the  head  at 
which  it  commenced,  having  numerous  coecal 
stomachs  communicating  with  its  cylindrical 
equal  canal  throughout  its  whole  course.  This 
circular  form  of  intestine  opening  at  both  its 
extremities  in  the  same  ciliated  aperture,  is 
seen  also  in  the  carchesium,  zoocladium,  episty- 
lis,  ophrydium,  vaginicola,  and  other  genera, 
which  from  this  character  are  termed  cyclocasla. 
In  some  of  the  animalcules  of  this  group,  as  in 
the  stentor  polymorphic,  (fig.  5  M,)  the  intes- 


Fis.  5. 


■xnt 


Fig.  6. 


tine  pursuing  the  same  circular  course  through 
the  body,  is  sacculated  or  irregularly  dilated  into 
round  vesicles  throughout  its  whole  length,  and 
from  these  enlarged  parts  the  little  stomachs 
commence  by  short  narrow  necks.  In  other 
species  of  the  stentor  the  intestine  is  twisted  in 
a  spiral  manner  throughout  its  circular  course. 
Many  of  the  polygastric  animalcules  which  ap- 
proach nearer  to  the  helminthoid  classes  in  the 
lengthened  form  of  their  body,  have  the  mouth 
and  anus  placed  at  the  opposite  extremities,  as 
in  these  higher  classes.  In  the  long  body  of 
the  enchelis  pupa,  (fig.  6,)  the  intestine  is 
seen  passing  straight  and  cylindri- 
cal through  the  body  from  the  wide 
ciliated  terminal  mouth  (fig.  6,  a) 
to  the  opposite  dilated  anal  termi- 
nation (fig.  6,  b)  and  giving  off 
numerous  small  sacs  along  its  whole 
course.  Such  animalcules  form  the 
group  termed  orthocala  from  this 
straight  course  of  the  intestine.  The 
intestine,  however,in  the  leucoplirys 
patula  (fig.  5  A)  passes  in  a  spiral 
course  through  the  short  and  broad 
body  of  the  animalcule,  giving  off 
small  stomachs  or  cceca  along  its 
whole  course,  and  such  crooked 
forms  of  the  alimentary  canal  com- 
pose the  group  of  campylocorta,  in 
the  distribution  of  this  class  proposed  by 
Ehrenberg. 

Thirty-five  genera  of  polygastrica  present  an 
intestine  passing  through  their  transparent  body, 
and  developing  from  its  parietes  these  minute 
globular  cceca,  which  have  been  regarded  as 
stomachs,  from  the  quickness  with  which  the 
animalcule  conveys  the  food  into  them,  and 
from  its  not  accumulating  or  retaining  its  food 
in  any  other  part  of  the  digestive  apparatus. 
More  than  a  hundred  of  these  stomachs  have 
been  seen  in  the parammcium  and  aurelia  filled 
at  the  same  time,  and  there  may  have  been 
many  more  unseen  from  their  empty  and  col- 
lapsed state.    These  little  sacs  are  contracted, 


30 


echinodermata. 


filiform, and  almost  invisible,  when  empty;  but 
they  are  susceptible  of  great  dilatation,  and 
are  sometimes  seen  filled  with  water  or  dis- 
tended with  smaller  animalcules  seized  as  food. 
Viewed  through  the  microscope  these  minute 
animals  present  very  different  appearances,  ac- 
cording to  the  quantity  and  kind  of  food  con- 
tained in  their  ccecal  appendices,  and  from  this 
circumstance  twelve  different  species  of  animal- 
cules, belonging  to  six  supposed  distinct  genera, 
have  been  formed  of  the  single  vorticella  con- 
vallaria.  No  glandular  organs  to  assist  in 
digestion  have  been  observed  in  the  polygastric 
animalcules  ;  and  notwithstanding  their  almost 
invisible  minuteness  and  the  great  simplicity 
of  their  structure,  they  appear  to  be  the  most 
numerous,  the  most  active,  the  most  prolific, 
and  the  most  voracious  of  all  living  beings. 
Very  recently,  by  the  aid  of  an  improved  mi- 
croscope made  at  Berlin,  Ehrenberg  has  been 
able  to  detect  a  dental  apparatus  in  the  kolpoda 
cucullulus  of  Muller,  one  of  these  minute  poly- 
gastric animalcules,  which  shews  a  further  ana- 
logy between  them  and  the  helminthoid  articu- 
lata.  Notwithstanding  the  number  of  stomachs 
in  this  class  of  animals,  and  the  infinite  variety 
Of  prey  which  commonly  surround  them,  we 
often  observe  them  devouring  animals,  which 
from  their  magnitude  are  incapable  of  being 
conveyed  into  these  cavities.  I  have  observed 
a  trachelitis,  after  swallowing  several  monads 
which  swarmed  around  it,  proceed  slowly  to 
swallow  down  a  trkhoda,  which  appeared  to 
be  ten  times  the  size  of  one  of  its  internal  sacs. 
It  took  about  a  minute  to  swallow  the  trkhoda, 
after  having  turned  it  in  different  directions 
with  its  long  transparent  moveable  upper  lip. 
The  prey  could  not  be  perceived  to  offer  the 
slightest  resistance,  while  the  trachelitis,  with 
its  upper  lip  spread  over  the  small  anterior  end 
of  the  trkhoda,  gradually  advanced  and  ex- 
panded the  short  lower  lip  to  embrace  it  below. 
The  body  of  the  trachelitis  was  much  shortened 
during  this  prolonged  act,  being  drawn  forwards 
towards  the  lips,  and  the  animalcule,  become 
slower  in  its  movements,  was  sensibly  distended 
on  one  side  by  this  large  prey  in  the  intestine ; 
but  in  less  than  half  an  hour  it  had  recovered 
its  usual  lengthened  form  and  gliding  move- 
ments, and  was  seen  to  seize  again  the  smaller 
monads  around  it.  Ehrenberg  has  figured  an 
enchelys  swallowing  a  loxodes  ten  times  the 
size  of  its  stomachs  even  when  filled  with  car- 
mine, and  in  the  body  of  the  loxodes  he  has 
represented  navic'iiRe  which  have  been  swal- 
lowed, though  several  times  the  size  of  any  of 
its  stomachs  distended  with  sap-green.  In  the 
capacious  alimentary  cavity  of  the  paramacium 
chrysalis  I  have  found  a  constant  slow  revolu- 
tion of  the  whole  contents,  like  the  cyclosis  in 
the  large  cells  of  a  chara,  and  the  round  sacs 
appear  often  to  be  driven  to  and  fro  like  loose 
balls  in  a  sac.  Baron  Gleichen  has  figured 
some  of  these  round  sacs  of  Ehrenberg  separate 
from  the  animalcules,  as  a  bolus  of  matter 
which  had  escaped  per  anum.  These  round 
transparent  bodies  are  often  hurried  to  one  end 
of  the  animalcule's  body  and  then  to  the  oppo- 
site, or  spread  generally  through  the  cavity, 


and  they  sometimes  join  partially  in  the  general 
internal  cyclosis  of  the  abdominal  cavity.  In 
many  genera  of  polygastric  animalcules  a  cir- 
cular proboscis  is  seen  around  the  mouth, 
composed  of  long  parallel  straight  teeth  closely 
applied  to  each  other,  which  can  be  extended 
or  retracted,  and  forms  their  masticating  appa- 
ratus. 

(For  the  higher  forms  of  the  alimentary  canal 
in  all  the  separate  classes  of  the  animal  king- 
dom, see  the  names  of  the  several  classes  from 
the  Porifera  to  the  Mammalia,  Animal 
Kingdom,  and  the  preceding  article  Diges- 
tion.) 

(R.  E.  Grant.) 

ECHINODERMATA,  (e^.™?,  echinus— 
^fj/xa,  coriu/n,)  Fr.  Echinodermes.  A  class 
of  invertebrate  animals  belonging  to  the  di- 
vision lladiata  or  the  Cycloneurose  sub-king- 
dom. The  most  familiar  examples  of  them  are 
the  common  sea-urchin  and  star-fish. 

In  these  the  skin  is  covered  with  prickles,  a 
circumstance  from  which  the  class  has  received 
its  name ;  but  animals  of  corresponding  in- 
ternal structure,  such  as  the  Holothuria,  are 
also  comprehended  among  the  Echinodermata, 
although  the  skin  is  destitute  of  prickles. 
They  are  all  inhabitants  of  the  sea,  examples 
of  them  are  found  in  all  climates,  and  the 
remains  of  extinct  species  exist  in  a  fossil  state 
in  various  mineral  strata. 

Naturalists  are  not  agreed  as  to  the  limits 
of  this  class.  Cuvier  includes  in  it  two  orders 
of  animals;  the  first  provided  with  tubular 
retractile  organs  named  feet,  the  second  desti- 
tute of  feet,  but  allied,  he  conceives,  to  the  first 
in  other  respects.  Other  zoologists  separate  this 
second  order  of  Cuvier  from  the  Echinoder- 
mata. But  in  fact  these  apodous  animals, 
comprehending  the  genera  Molpadia,  Minyas, 
Priapulus,  and  Sipunculus,  are  as  yet  so  im- 
perfectly known,  at  least  as  regards  their  in- 
ternal structure,  that  naturalists  seem  at  a  loss 
to  discover  their  appropriate  place  in  the  zoo- 
logical system.  In  these  circumstances  we 
shall  confine  ourselves  to  the  consideration  of 
the  true  or  pedicellate  Echinodermata,  of  whose 
systematic  arrangement  the  following  is  a  tabu- 
lar view. 

Order  I.  ASTEROIDEA  or  STELLE- 
RIDA. 

Body  depressed,  divided  into  rays  like  a  star, 
or  at  least  with  prominent  angles.  Mouth 
inferior,  generally  no  anus. 

a.  Holes  for  the  feet  disposed  in  grooves 
on  the  inferior  surface. 

Genus  1.  Asterias,  (figs-  298  vol.  i. 
7-22.) 

b.  No  grooves  for  the  feet. 

Genus  2.  Ophiura.  Rays  simple,  elon- 
gated, cirrhous,  with  lateral  spines. 

Genus  3.  Euryale.  Rays  long,  cir- 
rhous, divided  dichotomously. 

Genus  4.  Comatula.  Rays  in  two 
sets,  dorsal  and  marginal.  The  dor- 
sal rays  simple,  filiform,  cirrhous. 
The  marginal  much  larger  and  pin- 
nated, their  inferior  pinnules  turned 


ECIIINODERMATA. 


31 


downwards  and  surrounding  the  ven- 
tral disk.  Border  of  the  mouth 
formed  by  a  prominent  membranous 
tube. 

Genus  5.  Encrinus.  Body  supported 
on  a  jointed  stem.    (With  one  ex- 
ception the  species  are  all  fossil.) 
Order  II.  EC  HI  JS  IDA. 
Body  globular  or  ovoid,  without  rays  ;  skin 
containing  a  calcareous  shell ;  anus  distinct. 

a.  liegularia.  Mouth  and  anus  diametri- 
cally opposite  in  the  centre  of  the  ventral 
and  dorsal  surface  respectively. 

Genus  1.  Echinus,   (figs.  33  vol.  i. 

10-19.) 
Genus  2.  Cidarites. 

b.  Mesostoma.  Mouth  in  the  centre,  anus 
eccentric. 

Genus 

r 


Anus  on 
the  ventral 
surface  or 
the  border. 


3.  Galerites. 

4.  EciIINONEUS. 


f  Rows  of  feet 
[  extending 
J  from  the  anus 
*  to  the  inferior 
opening  of  the 
shell. 


8.  Cassidulus. 

9.  NuCLEOLITES. 


Rows  of  feet 
not  extending 
►to  the  inferior 
opening  of  the 
shell. 


Mouth  and  anus  both  ec- 


5.  Scutella. 

6.  Clypeaster, 
„  7. Fibularia. 

Anus 
above  the 
border 
dorsal . 

c.  Plagyostoma. 
centric. 

Genus  10.  Ananchites. 
Genus  11.  Spatangus. 
Order  III.  HO  LOTH  U  RIM. 
Body  oblong,  (fig.  34  vol.  i.)  coriaceous,  with 
the  anus  (k)  and  mouth  (a)  at  its  opposite 
extremities.    Mouth  surrounded  with  retrac- 
tile, branched  tentacula  (o).    Organ  of  re- 
spiration a  ramified  tube  (fi,.f,,f),  placed 
within  the  body  and  opening  at  the  anus. 
Genus.  Holothuria.  (Jig.  34  p.  109, 
vol.  i.  and  Jig.  20.) 
The  genera  Aster ias,  Echinus,  and  Holo- 
thuria are  those  in  which  the  internal  struc- 
ture has  been  most  frequently  and  fully  inves- 
tigated ;  they  are  therefore  usually  selected  as 
the  leading  examples  in  anatomical  descriptions 
of  the  Echinodermata,  the  peculiarities  of  other 
genera  being  mentioned  in  so  far  as  they  have 
been  satisfactorily  ascertained,  and  are  of  suffi- 
cient importance  to  demand  special  notice. 

1.  Integuments. — An  incision  made  through 
the  tough  skin  of  the  star-fish  or  shell  of  the 
sea-urchin,  lays  open  the  internal  cavity  of 
the  body  in  which  the  viscera  lie;  so  that  in 
these  animals  the  integuments  in  a  great  mea- 
sure constitute  the  parietes  of  the  body,  there 
being  little  else  except  the  peritoneum  or  lining 
membrane  of  the  visceral  cavity  which  is  spread 
over  their  internal  surface.  In  the  Holothuria 
there  are  muscles  of  considerable  thickness  be- 
neath the  skin.  The  integuments  of  the  former 
animals  contain  imbedded  pieces  of  calcareous 
substance,  which  constitute  a  kind  of  cutaneous 
skeleton.  In  the  latter  there  is  merely  a  calca- 
reous ring  surrounding  the  mouth. 

a  In  the  Asterias  the  integuments  consist  of, 


1st,  a  tough  coriaceous  membrane,  with  por- 
tions of  calcareous  substance  imbedded  in  it, 
or  at  least  connected  by  it ;  2d,  a  softer  external 
membrane ;  3d,  various  appendages.  The 
calcareous  pieces  form  inferiorly  a  ring  round 
the  mouth  and  a  series  of  transverse  segments 
(from  a  to  A,Jig.7;  C,  fig.  22,)  placed  in  succes- 
F)g.  7. 


Inferior  view  of  Asterias  rubens:  at  A  part  of  the 
feet  ts  removed. 

sion  along  the  floor  of  each  ray.  The  first  of  these 
segments  is  connected  with  the  ring;  they  de- 
crease in  size  as  they  approach  the  point  or 
distal  end  of  the  ray,  and  openings  are  left 
between  them  for  the  passage  of  the  feet.  In 
the  Asterias  rubens,  which  has  five  rays,  the 
central  ring  consists  of  ten  larger  and  five 
smaller  pieces,  the  former  disposed  in  pairs 
opposite  the  commencement  of  the  rays,  the 
latter  corresponding  to  the  angles  between  the 
rays.  The  segments  of  the  rays  are  symme- 
trical ;  in  the  species  mentioned  they  consist 
of  two  oblong  pieces  {a,  Jig.  8),  united  in  the 
Fig.  8. 


Section  of  a  ray  of  Asterias  rubens,  showing  the 
arrangement  of  the  calcareous  pieces. 


32 


ECIIINODERMATA. 


median  line,  and  two  smaller  ones  (b,  b,) 
placed  laterally.  On  the  sides  of  the  ray  the 
calcareous  substance  is  disposed,  as  it  were,  in 
ribs  (c,  c,  Jig.  9) ;  these  rise  from  the  floor  at 
first  nearly  parallel  with  each  other,  and  are  con- 
nected by  cross  bars,  but  on  approaching  the 
upper  part  or  roof  of  the  ray  they  cross  in  all 
directions  and  form  an  irregular  network,  the 
intervals  of  which  are  occupied  by  softer  inte- 
gument. The  ribs  and  bars  are  made  up  of 
small  pieces  joined  by  plane  but  oblique  sur- 
faces, a  mode  of  construction  calculated  to 
admit  of  their  being  lengthened  and  shortened 
upon  one  another,  and  thus  to  allow  of  the  ca- 
vity they  surround  being  dilated  and  contracted. 

Fig.  9. 


Portion  of  a  ray  of  Asterias  rubens  viewed  laterally. 

A  broad  calcareous  disk  is  situated  on  the 
upper  surface  of  the  body,  in  the  angle  be- 
tween two  of  the  rays,  (jigs.  12  and  1 6,  z,)  which 
is  connected  internally  with  a  singular  organ 
named  by  Tiedemann  the  sand  canal,  to  be 
afterwards  described.  The  calcareous  pieces 
are  of  a  homogeneous  structure,  without  cells 
or  fibres ;  they  consist,  according  to  Hatchett's 
analysis,  of  carbonate  of  lime,  with  a  smaller 
proportion  of  phosphate  of  lime. 

The  coriaceous  membrane  which  connects 
the  pieces  of  the  skeleton  is  made  up  of  white 
glistening  fibres.  It  is  contractile  and  irritable, 
for  it  slowly  shrinks  on  being  scratched  with 
the  point  of  a  knife,  or  when  it  is  cut  through. 

The  external  membrane  is  much  thinner  and 
softer  than  that  just  described  ;  in  various  parts 
it  is  coloured,  or  in  these  parts  there  is  a  co- 
loured layer  underneath  it. 

The  appendages  or  processes  on  the  surface 
of  the  body  are  of  three  kinds.  First,  calcareous 
spines ;  these  are  found  over  the  whole  surface 
except  the  grooves  for  the  feet.  They  are  at- 
tached by  a  moveable  joint  at  their  base  to  the 
calcareous  pieces  of  the  skin,  and  are  invested 
by  the  external  soft  membrane  nearly  as  far  as 
their  point.  Those  on  the  upper  surface  are 
solitary,  short,  and  for  the  most  part  club- 
shaped,  their  broader  summit  being  marked 
with  radiating  points  ;  whence  they  were  named 
stelliform  processes  by  Tiedemann.  On  each 
side  of  the  groove  for  the  feet  the  spines  are 
thickly  set  (<*,  c,  jig.  7) ;  these  in  Asterias 
rubens  form  three  rows,  in  the  middle  and 
innermost  of  which  they  are  placed  three  deep. 
On  this  part  of  the  surface  they  are  also  longer 
and  pointed.  The  spines  are  slowly  moved  at 
the  will  of  the  animal. 

The  appendages  of  the  second  kind  are  of  a 


very  singular  nature ;  they  have  the  appearance 
of  pincers  or  crabs'  claws  in  miniature  (Jig.  298, 
c,  b,  b,  p.  615,  vol.  i.)  and  were  described 
by  Miiller  as  parasitical  animals  under  the 
name  of  Pedicellaria.  Monro  gave  the  name 
of  antenna?  to  analogous  organs  which  are 
found  on  the  sea-urchin.  They  probably  do 
not  exist  in  all  species,  for  Tiedemann  makes 
no  mention  of  them  in  his  description  of  A. 
auranliaca.  In  A.  rubens  they  cover  the 
surface  generally,  and  form  dense  groups  round 
the  spines.  Each  consists  of  a  soft  stem 
bearing  at  its  summit,  or  (when  branched)  at 
the  point  of  each  branch,  a  sort  of  forceps  of 
calcareous  matter  not  unlike  a  crab's  claw, 
except  that  the  two  blades  are  equal  and  similar. 
When  the  point  of  a  fine  needle  is  introduced 
between  the  blades,  which  are  for  the  most 
part  open  in  a  fresh  and  vigorous  specimen, 
they  instantly  close  and  grasp  it  with  consi- 
derable force.  The  particular  use  of  these 
prehensile  organs  is  not  apparent ;  their  stem, 
it  may  be  remarked,  is  quite  impervious. 

The  third  sort  of  appendages  consists  of  those 
which  are  named  the  respiratory  tubes;  they 
will  be  considered  afterwards. 

The  other  genera  of  Asteroidea  have  also  a 
cutaneous  skeleton  presenting  the  same  general 
mode  of  construction  as  that  of  Asterias,  but 
with  certain  modifications  of  structure  and  stdl 
greater  differences  of  form  in  particular  cases. 
Of  these  we  may  here  notice  the  crinoid  ec/ii- 
nodermata  and  the  genus  comatula,   as  the 
most  interesting  examples.    The  former  ani- 
mals, comprehended  by  most  naturalists  in  the 
genus  Encrinus,  are,  with  one  exception  ( the 
Enc.  caput  medusa  or  Pentacrinitc )  found  only 
in  a  fossil  state,  and  the  remains  of  their  ske- 
letons constitute  the  fossils  named  encrinites, 
trochites,  entrochites,  &c.    An  idea  of  their 
structure  may  be  obtained  if  we  imagine  an 
asterias  placed  with  its  mouth  upwards  on  a 
columnar  jointed  stem,  one  end  of  which  is 
connected  to  the  dorsal  surface  of  the  animal, 
and  the  other  most  probably  fixed  at  the  bottom 
of  the  sea.    The  rays  or  arms  extending  from 
the   circumference  of  the  body  are  much 
branched,  and  at  last  pinnated  ;  other  jointed 
processes,  named  auxiliary  arms,  surround  the 
stem  in  whorls  placed  at  short  intervals.  The 
column  is  perforated  in  its  centre  with  a  narrow 
canal,  down  which  a  prolongation  of  the  sto- 
mach extends,  and  lateral  canals  proceed  from 
the  central  one  through  the  verticillate  auxiliary 
arms.    The  Comatula  has  rays  spreading  from 
the  circumference  of  the  body,  branched  and 
pinnated  like  those  of  the  pentacrinite.    It  is 
not  fixed  on  a  column,  but  the  dorsal  surface 
of  the  body  is  elevated  in  the  middle,  and 
bears  a  number  of  smaller  rays  or  arms,  and 
this  dorsal  eminence  with  its  rays  has  been 
sometimes  compared  to  a  rudiment  of  the 
column  of  the  pentacrinite  with  its  auxiliary 
arms.     Besides  the  mouth  there  is  an  anal 
opening  on  the  ventral  surface,  situated  on  an 
eminence  near  the  margin.* 

b.  In  the  sea-urchin  the  calcareous  matter  is 
disposed  in  polygonal  plates,   which,  being 

*  Meckel,  Vergl.  Anat.  ii.  p.  31. 


ECHINODERMATA. 


33 


firmly  joined  to  one  another,  form  by  their 
union  a  shell  approaching  more  or  less  to  a 
spherical  figure,  (Jig.  10,  A,  B.)  The  shell  is 
covered  outside  by  a  membranous  integu- 
ment, spines,  and  other  appendages;  on  the 
inside  it  is  lined  by  the  peritoneum.    It  is 

Fig.  10.  A. 


Fig.  10.  B. 


Echinus  esculentus  opened,  intestine  removed. 
A,  under  half  of  shell.  B,  upper  half,  o,  oeso- 
phagus cut.  b,  termination  of  the  intestine. 
c,  c,  c,  ovaries,  d,  d,  vesicular  laminae  of  the 
feet.  At  e,  e,  the  lamina?  are  removed  to  show 
the  perforations  for  the  feet. 

perforated  above  for  the  anal  orifice  of  the 
intestine  (6),  and  below  it  presents  a  much 
larger  opening,  which  is  closed  by  the  mem- 
branous integument,  except  in  the  middle, 
where  the  mouth  is  situated  (fig.  15).  The 
pieces  composing  the  shell  are  mostly  five- 
sided,  transversely  oblong,  and  disposed  in 
twenty  vertical  rows  or  columns,  which  extend 
from  the  anus  to  the  inferior  opening.  Ten  of 
the  columns  are  narrower,  and  consist  of  smaller 
pieces,  (fig-  10,  e,  e,)  which  are  perforated 
with  holes  for  the  feet ;  they  are  thence  termed 
ambulacral.  The  other  ten  are  broader,  and 
consist  of  larger  pieces  (f,f).  The  ten  am- 
bulacral columns  are  disposed  in  five  pairs, 
with  which  the  ten  larger  columns,  also  dis- 
posed in  pairs,  alternate.  The  two  columns  of 
each  pair  are  joined  by  a  zigzag  line.  The 

VOL.  II. 


upper  ends  of  the  columns  are  connected  with 
ten  plates,  alternately  larger  and  smaller,  placed 
round  the  anus ;  the  larger  perforated  for  the 
passage  of  the  oviducts,  and  named  ovarial 
plates,  the  smaller  also  perforated  by  a  smaller 
hole,  which  is  connected  with  the  vascular  sys- 
tem. At  its  lower  edge  the  shell  sends  inwards 
a  process  in  form  of  an  arch  over  each  pair  of 
the  ambulacral  columns  (g,  g,  g).  The  number 
of  plates  in  a  row  varies  with  the  age  of  the 
animal,  increasing  as  it  grows  older  and  larger. 
They  are  marked  on  the  outside  with  tubercles 
or  knobs,  of  various  sizes,  which  support  the 
spines.  The  spines  themselves  have  a  cup-like 
cavity  at  their  base,  which  is  connected  with 
and  moves  on  the  prominent  tubercle,  the 
union  being  effected  at  the  circumference  of 
the  articulation  by  the  soft  irritable  integu- 
ment, or,  according  to  some,  by  distinct  mus- 
cular fibres. 

Besides  the  spines,  there  exist  on  the  external 
surface  of  the  Echinus  appendages  (fig.  11), 
of  the  same  nature  as  the  claw-like  organs  of 
the  Asterias,  only  that  in  the  Echinus  the  sort 
of  forceps  which  they  bear  at  their  extremity 
for  the  most  part  consists  of  three  blades. 

Fig.U. 


The  shell  of  the  irregularly-shaped  Echinida 
differs  considerably  in  structure  from  that  of 
Echinus.  The  division  into  plates  is  less  ob- 
vious, and  in  some  cases  disappears  altogether. 
The  series  of  holes  or  ambulacra  do  not  extend 
uninterruptedly  from  the  anus  to  the  lower 
orifice.  Lastly,  in  Clypeaster  the  shell  is  di- 
vided interiorly,  by  vertical  calcareous  parti- 
tions, into  five  compartments  which  commu- 
nicate together,  the  septa  being  incomplete. 

c.  The  integuments  of  the  Holothuriae  differ 
considerably  in  different  species.  In  those 
species  in  which  there  is  a  marked  distinction 
of  the  dorsal  and  ventral  surface  of  the  body, 
the  integument  differs  in  character  on  these 
two  surfaces  :  in  other  cases  it  is  pretty  nearly 
uniform  over  the  whole  body.  It  in  general 
consists  of  a  white  fibrous  layer,  which  consti- 
tutes its  chief  thickness,  and  a  soft  coloured 
layer  and  epidermis  placed  more  exteriorly. 
In  some  species  the  skin  exhibits  hard  conical 
warts  scattered  over  the  dorsal  surface;  in  others 
it  contains  imbricated  calcareous  scales.  In 
H.  phantapus,  in  addition  to  these  scales, 
which  are  about  a  line  in  breadth,  the  in- 
tegument, according  to  our  observation,  is 
thickly  beset  with  small  calcareous  eminences, 
about  ^5  of  an  inch  in  diameter,  resembling, 
except  in  size,  the  short  calcareous  processes 
on  the  upper  surface  of  the  Asterias. 

A  calcareous  ring,  forming  in  many  species 
the  only  hard  part  of  the  body,  surrounds  the 


34 


ECHINODERMATA. 


mouth.  It  is  made  up  of  ten  pieces  alternately 
larger  and  smaller,  and  gives  attachment  to  the 
longitudinal  muscles  of  the  body.  It  is  re- 
garded as  the  rudiment  of  a  skeleton,  while 
the  addition  of  scales  or  plates  in  the  skin 
forms  in  some  species  an  approach  to  the  more 
perfect  cutaneous  skeletons  of  the  star-fish  and 
sea-urchin. 

2.  Organs  of  motion. — The  spines  of  some 
Echinodermata  are  employed  to  a  certain  extent 
as  organs  of  locomotion;  they  have  been  al- 
ready described.  The  star-fish  has  the  power 
of  slowly  moving  its  rays ;  it  can  bend  them 
towards  the  dorsal  or  ventral  surface,  or  ap- 
proximate some  of  them  while  it  separates 
others  more  widely,  and  thus  prepare  itself  for 
creeping  through  narrow  passages.  Tiedemann 
ascribes  these  motions  wholly  to  the  contractile 
skin  ;  they  are  no  doubt  partly  effected  by  that 
tissue,  but  Meckel  describes  distinct  muscles 
passing  between  the  calcareous  plates  which 
form  the  floor  of  the  rays,  and  we  have  our- 
selves observed  a  distinct  band  of  muscular 
fibres  running  along  the  roof  of  each  ray  be- 
tween the  coriaceous  skin  and  peritoneal  mem- 
brane, and  also  transverse  fibres,  but  less 
marked,  lying  between  the  same  parts ;  the 
latter  are  seen  adhering  to  the  external  surface 
of  the  peritoneal  membrane  when  it  is  stript 
off. 

The  muscular  system  of  the  Holothuria  is 
much  more  developed.  Ten  longitudinal  mus- 
cles (jig.  20,  s,  s,  s,)  arise  from  the  calcareous 
ring  in  the  vicinity  of  the  mouth,  and  pass 
along  the  body  in  the  form  of  broad  bands  to 
the  posterior  extremity;  between  these  and  the 
skin  transverse  or  circular  muscles  (/,  /,)  are 
situated;  they  extend  over  the  whole  internal 
surface  of  the  skin. 

The  principal  locomotive  organs  of  Echino- 


dermata are  the  membranous  tubes  named  the 
feet.  These  are  very  numerous  and  are  usually 
disposed  in  regular  rows;  they  contain  a  clear 
fluid,  which  is  conveyed  to  them  by  a  peculiar 
system  of  vessels.  Each  foot  consists  of  two 
parts,  an  internal  and  generally  vesicular  por- 
tion (Jig.  12,  d,)  placed  within  the  body,  and  a 
tubular  part  (c)  on  the  outside,  projecting  from 
the  surface  and  continuous  with  the  first  through 
an  aperture  in  the  skin  or  shell  (Jig.  23,/J.  The 
tube  is  closed  at  the  extremity  and  terminates 
there  in  a  sucker,  which  has  usually  the  form 
of  a  disk  slightly  depressed  in  the  centre. 
Both  parts  of  the  foot  are  evidently  muscular, 
the  fibres  of  the  tubular  portion  being  disposed 
in  a  circular  and  a  longitudinal  layer;  the 
cavity  is  lined  with  a  transparent  membrane, 
and  the  tubular  part  moreover  receives  an 
external  covering  from  the  epidermis.  The 
foot  is  extended  by  the  contraction  of  its  inter- 
nal vesicle,  which  forces  the  fluid  into  the  tube, 
or  when  a  vesicle  is  wanting,  by  the  projection 
of  a  fluid  into  the  tube  from  a  communicating 
vessel ;  the  tubular  part  is  thus  distended  and 
elongated  ;  it  retracts  itself  of  course  by  its 
muscular  fibres,  and  when  this  takes  place  the 
fluid  is  forced  back  again  into  the  vesicular 
or  internal  part.  In  progression  the  animal 
extends  a  few  of  its  feet  in  the  direction  in 
which  it  desires  to  go,  attaches  the  suckers  to 
rocks,  stones,  or  other  fixed  objects  immedi- 
ately in  advance,  then  shortening  its  feet  it 
draws  its  body  in  the  wished-for  direction. 

a.  In  the  starfish  the  feet  are  disposed  in 
rows  along  the  under  surface  of  the  rays,  di- 
minishing in  size  as  they  approach  the  extre- 
mity (Jig.  7,  a,  b,  d).  There  are  usually  two  sim- 
ple rows  in  each  ray,  (fig.  23,  c,J  and  the  vesi- 
cular part  is  for  the  most  part  deeply  cleft  into  two 
lobes  (as  in  A.  aurantiaca,  fig.  22,  d,  d ).  In 


Fig.  12. 


ECHINODERMATA. 


35 


other  cases,  as  A.  rubens,  there  are  two  double 
rows  (Jig.  7,  b,)  in  every  ray,  and  each  foot 
has  a  round  undivided  vesicle  (Jigs.  12  and 
16,  d). 

The  canals   or  vessels  which  convey  the 
fluid  to  and  from  the  feet  are  all  connected  with 
a  circular  vessel  situated  in  the  vicinity  of  the 
mouth.    This  vessel  (Jigs.  12  and  22,  i,  i,)  lies 
immediately  within  the  calcareous  ring  already 
described  as  connecting  the  rays  at  their  com- 
mencement ;  from  it  a  straight  canal  proceeds 
along  the  floor  of  each  ray  in  the  median  line, 
and  in  its  progress  gives  off  lateral  branches 
which  open  into  the  vesicles  of  the  feet.  There 
are  moreover  connected  with  the  circular  ves- 
sel,— first,  a  certain  number  of  bodies  (ten  in 
five-rayed   species)  which  Tiedemann  com- 
pares to  glands  (Jigs.  12  and  22,  m,  m);  they 
are  very  small,  brown,  sacculated  organs,  each 
opening  by  a  small  orifice  into  the  circular 
vessel;  Tiedemann  supposes  them  to  be  the 
source  from  which  the  fluid  filling  the  feet  is 
derived.    Secondly,  pyriform  sacs;  mA.au- 
rantiaca  there  are  four  groups  of  these  (Jig. 
22,  k);   and  each  group  consists  of  three 
or   four   sacs  which    open   by  a  common 
tubular  pedicle  into  the  circular  vessel.  In  some 
other  species  there  are  five  simple  sacs.  They 
are  muscular,  and  Tiedemann  conceives  them 
to  be  the  chief  agents  by  which  the  fluid  is 
forced  into  the  vesicles  of  the  feet,  to  which 
they  are  placed  in  a  sort  of  antagonism.  It 
would  seem,  however,  that  this  purpose  may 
be  accomplished  by  other  means,  for  according 
to  Meckel's  statement,  and,  we  may  add,  our 
own  observation,  they  are  not  present  in  all 
species.    Lastly,  the  circular  vessel  receives 
the  singular  organ  named  the  stone  canal  or 
sand  canal  by  Tiedemann,  (figs.  12  and  22,  S,) 
who  describes  it  as  a  membranous  eanal  con- 
taining a  friable  mass  of  sandy  or  earthy 
matter,  which  commences  by  a  wide  origin  on 
the  inferior  or  internal  surface  of  the  calcareous 
disk  (Jigs.  12  and  16,  z,)  already  described 
as  situate  on  the  upper  part  of  the  body, 
descends  in  a  duplicature  of  fibrous  membrane, 
and  opens  by  a  narrow  orifice  into  the  circular 
vessel,  the  upper  or  wide  end  being  closed  by 
the  disk.    Ehrenberg  has  correctly  remarked 
that  this  organ  is  not  filled  with  an  amorphous 
mass  of  earthy  or  cretaceous  matter ;  he  de- 
scribes it  as  exhibiting  a  dense  network  of 
calcareous  fibres  with  hexagonal  and  penta- 
gonal meshes,  resembling  in  some  respects  the 
cavernous  structure  of  the  penis.    The  result 
of  our  own  examination  in  more  than  one 
species  is  different  still.     We  have  always 
found  the  earthy  matter  forming  a  jointed  cal- 
careous tube.    This  tube,  which  is  about  the 
thickness  of  a  surgeon's  probe,  is  composed 
of  rings  of  calcareous  substance  connected  by 
membrane,  so  that  viewed  externally  it  is  not 
unlike  the  windpipe  of  a  small  animal.  On 
cutting  it  across,  however,  it  is  found  to  be 
more  complex  in  structure  than  appears  exter- 
nally, for  it  contains  within,  two  convoluted 
lamince  of  the  same  nature  as  its  calcareous 
parietes  (fig.\3).  These  lamina?  are  rolled  lon- 
gitudinally; they  rise  conjointly  or  as  one,  from 


Portion  of  the  sand 
canal  of  Asterias 
rubens,  magnified. 


Fig.  13. 

the  internal  surface  of  the 
tube,  pass  inwardly  a  cer- 
tain way,  then  separating 
are  rolled  in  opposite  di- 
rections ;  something  after 
the  same  manner  as  the 
inferior  turbinated  bone  of 
the  ox.  These  internal 
laminae  become  more  con- 
voluted towards  the  upper 
end,  where  at  last  they,  as 
well  as  the  more  external 
part  of  the  tube,  join  the 
dorsal  disk,  appearing  gra- 
dually to  -become  conti- 
nuous with  its  substance. 
The  disk  is  perforated  with  numerous  pores 
which  open  into  the  tube.  Tiedemann  con- 
ceives the  function  of  the  sand  canal  to  be  that 
of  secreting  the  earthy  matter  required  for  the 
growth  of  the  calcareous  skeleton.  Meckel 
considered  this  view  as  very  improbable,  and 
the  description  we  have  given  does  not  tend  to 
corroborate  it.  We  must  confess  ourselves 
unable  to  offer  more  than  mere  conjecture  as  to 
the  use  of  this  singular  structure.  If  the  fluid 
contained  in  the  feet  and  their  vessels  be  sea- 
water,  (either  pure  or  with  an  admixture  of 
organic  particles,)  which  is  probable  from  its 
chemical  composition,  may  it  not  be  intro- 
duced and  perhaps  again  discharged  through 
the  pores  of  the  disk  and  the  calcareous  tube, 
the  porous  disk  serving  as  a  sort  of  filter  to 
exclude  impurities  ? 

In  the  Echinus  the  feet  are  disposed  in  ver- 
tical rows  running  from  the  anal  orifice  towards 
the  mouth;  and  the  corresponding  rows  of 
apertures  (fig.  10,  e,  e,)  thus  diverging  from  a 
point  have  been  compared  to  garden-walks, 
and  named  ambulacra.  In  most  cases  the  feet 
extend  all  the  way  to  the  inferior  opening  of 
the  shell,  but  in  some  genera  they  stop  short 
before  reaching  this  point.  There  are  ten  rows 
disposed  in  five  pairs.  The  tubular  part  of  each 
foot  communicates  with  the  interior  of  the  shell 
by  two  branches  which  pass  through  two  aper- 
tures. These  branches  in  some  species  (as 
E.  sexatalis)  communicate  directly  with  the 
canals  which  convey  the  fluid  to  the  feet ;  in 
others  (as  E.  esculentus )  they  open  into  a 
plexus  of  vessels,  by  the  intervention  of  which 
they  are  connected  with  the  canals.  The  plex- 
uses of  vessels  alluded  to  are  formed  in  leaf- 
like membranes  (Jig.  \A,d,d,  representing  two 
of  them  magnified,)  which  are  of  equal  num.- 

Fig.  14. 


ber  with  the  feet,  and  of  course  disposed  in 

d  2 


36 


ECHINODERMATA. 


double  rows  on  the  inside  of  the  shell  (Jig.  10, 
d.)  Monro  describes  each  foot  as  communi- 
cating with  two  of  these  laminae,  and  conse- 
quently every  lamina  as  receiving  a  branch  from 
two  feet;  in  our  own  dissections  we  have  al- 
ways found  that  both  branches  of  each  foot 
belonged  to  one  lamina.  These  branches  are 
represented  as  cut  at  a  in  the  annexed  figure. 

Five  longitudinal  vessels  run  down  on  the 
inside  of  the  shell,  there  being  one  in  the 
middle  of  each  double  row  of  feet  (figs.  10  and 
14,  u);  lateral  branches  go  off  from  these  either 
directly  to  the  feet  or  to  the  laminar  plexuses 
when  they  are  present.  The  five  longitudinal 
vessels  descending  towards  the  mouth  rise 
through  the  dental  apparatus  named  the  lan- 
tern, and  open  into  five  sacs  or  receptacles 
placed  on  its  upper  part,  where  according  to 
Tiedemann  they  terminate.  Monro  on  the 
other  hand  describes  the  sacs  as  communicating 
together,  and  states  that  from  them  the  liquor 
passes  down  the  sockets  of  the  teeth,  and  is 
discharged  into  the  sea.  The  vessels  and  la- 
minae are  highly  irritable,  and  by  their  contrac- 
tion distend  the  feet. 

Ten  tubular  tentacula,  similar  in  structure 
to  the  feet,  are  situated  in  the  vicinity  of  the 
mouth  (fig.  15,  d,  d,  d.)  In  Ech.  esculentus 
they  are  attached  to  the  small  calcareous  plates 


Fig.  15, 


Part  of  the  inferior  surface  of  tlie  Echinus, 
a,  mouth  ;    6,  b,  margin  of  the  inferior  open- 
ing of  the  shell ;  e,  e,  membrane  which  fills 
it. 

which  are  imbedded  in  the  membrane  that  fills 
up  the  aperture  of  the  shell.  The  plates  are 
each  pierced  with  a  hole,  through  which  the 
tentacula  communicate  with  the  canals  of  the 
feet. 

In  Holothuriee  the  feet  are  sometimes  scat- 
tered over  the  whole  surface  of  the  body; 
in  other  species  (as  H.  pentactes J  they  are 
placed  in  five  longitudinal  and  tolerably  regular 
rows  ;  while  in  others  again  they  are  confined 
to  the  ventral  surface,  as  in  H.  phantapus, 
where  they  form  only  three  rows.  The  tubular 
part  (fig-  20,  b,  b,)  is  in  general  very  shorty 
and  is  connected  with  a  simple  vesicle  inside. 
The  vessels  of  the  feet  arise  from  a  circular 
canal  which  surrounds  the  stomach  near  the 
fore  part  of  the  body.  One  or  sometimes  two 
large  pyriform  sacs  (Jig.  34,  b,  p.  109,  vol.  i.) 


open  into  this  canal,  and  a  number  of  small 
brown  hollow  glandular-like  bodies  are  also 
connected  with  it.  Five  vessels  issue  from  it, 
which  run  forwards  and  terminate  in  a  second 
canal  situate  immediately  within  the  calcareous 
ring  which  surrounds  the  mouth.  This  se- 
cond circular  canal  is  connected  with  the 
tentacula,  as  will  be  afterwards  described,  and 
it  gives  off  five  longitudinal  vessels  which  run 
towards  the  posterior  end  of  the  body,  and  dis- 
tribute lateral  branches  to  the  vesicles  of  the 
feet.  Tiedemann  regards  the  fluid  contained 
in  this  system  of  vessels  as  a  secretion,  and 
conceives  that  it  nourishes  the  skin,  the  mus- 
cles, and  tissue  of  the  feet,  besides  supplying 
to  the  latter  the  mechanical  means  of  their 
distension.  Further  observation  would,  how- 
ever, be  required  in  order  to  determine  its  true 
nature,  lor  there  is  much  reason  to  suspect 
that  the  fluid  of  the  feet  in  other  Echinoder- 
mata  consists  at  least  in  great  part  of  sea-water, 
and  it  is  not  to  be  supposed  that  in  the  Holo- 
thuria it  should  be  materially  different. 

Under  this  head  we  may  notice  the  tentacula 
of  the  Holothuria  (Jig.  34,  o,  p.  109,  vol.  i.)  re- 
tracted, as  they  present  a  great  analogy  in  struc- 
ture with  the  feet.  These  organs  are  placed  round 
the  mouth  and  are  twenty  in  number;  the  ex- 
tremity of  each  is  formed  into  a  circular  sucker 
surrounded  by  five  or  six  branched  processes. 
They  are  hollow,  and  a  great  part  of  them  is 
lodged  within  the  body ;  this  internal  part  is 
long  and  tapering,  and  communicates  by  a 
.small  orifice  with  the  anterior  circular  canal 
already  described,  from  which  the  tentacula 
receive  their  distending  fluid.  In  the  rest  of 
their  structure  and  in  their  mode  of  action  they 
resemble  the  feet.  They  seem  to  be  very  sen- 
sible, and  are  probably  used  as  organs  of  touch 
as  well  as  prehension.  In  H.  pentactes  the 
tentacula  are  very  large,  much  larger  than  in 
H.  tubulosa. 

3.  Digestive  organs. — The  digestive  appa- 
ratus is  very  simple.  The  sea-urchin  and 
Holothuria  have  an  alimentary  canal  with  a 
mouth  and  anus,  but  in  the  star-fish  there  is 
merely  a  stomach  with  coecal  appendages  and 
only  one  orifice.  The  cavity  in  which  the 
alimentary  organs  and  other  viscera  are  lodged 
is  lined  with  a  peritoneal  membrane,  which 
being  reflected  upon  them  forms  their  external 
tunic,  and  attaches  them  by  a  duplicature  or 
mesentery  to  the  inside  of  the  cavity.  The 
Echinodermata  are  said  to  live  chiefly  on  tes- 
taceous mollusca  and  Crustacea. 

a.  In  Asterias  a  short  but  dilatable  gullet 
leads  to  the  stomach  (Jigs.  16  and  22,  f),  which 
occupies  the  central  part  of  the  animal,  and 
from  the  stomach  a  pair  of  lobulated  coeca  (g, 
g,  and  g',  g',  inflated,)  pass  into  each  ray. 
The  stomach  is  connected  at  various  places 
with  the  parietes  of  the  body  by  ligamentous 
bands ;  it  is  thin  and  membranous,  soft  and 
corrugated  on  the  internal  surface,  receiving 
externally  a  covering  of  peritoneum,  and  con- 
taining muscular  fibres  which  are  more  obvious 
towards  the  lower  part,  when  it  adjoins  the 
still  more  muscular  oesophagus.  Two  or  more 
blind  sacs  (I),  branched  in  some  species,  open 


ECHINODERMATA. 
Fig.  16. 


37 


Asterias  rubens:  three  rays  opened — in  the  one,  at  A,  cceca  cut  short  to  shew  the  vesicles  of  the  feet, 
d,  d,  and  one  ovary,  o;  g,  g,  cceca,  g'  g' ,  coeca  inflated. 


into  it  from  above,  which  are  probably  secre- 
ting organs.  The  coeca  are  thin  and  mem- 
branous like  the  stomach;  each  consists  of  a 
central  tube  with  lateral  branches,  which  in 
their  turn  are  lobed  or  branched,  and  terminate 
in  cellular  dilatations.  The  two  coeca  of  a  ray 
sometimes  communicate  with  the  stomach  by  a 
short  single  tube  (A);  in  other  cases  they  have 
separate  orifices.  They  do  not  reach  so  far  as 
the  distal  end  of  the  ray;  each  one  is  attached 
to  the  roof  by  what  might  be  called  a  double 
mesentery,  for  the  peritoneum  forms  here  two 
duplicatures  (Jigs.  12  and  16,  n,)  between  the 
coecum  and  the  roof  of  the  ray.  A  space  is 
inclosed  between   these  duplicatures  which 


opens  into  the  central  part  of  the  body  at  the 
root  of  the  coeca. 

Such  is  the  structure  in  the  Asterias,  but  in 
some  other  genera  belonging  to  the  tribe  of 
Asteroidea  it  is  different.  In  Ophiura,  Eu- 
ryule,  and  Comatula,  in  which  the  rays  are 
very  long  and  slender,  the  cceca  are  mere  cel- 
lular dilatations  of  the  stomach,  and  do  not 
extend  into  the  rays.  Comatula  moreover  dif- 
fers from  all  the  tribe,  inasmuch  as  its  alimen- 
tary canal  has  two  openings,  a  mouth  and  anus, 
situated  near  to  each  other  on  the  ventral  sur- 
face. 

The  mouth  of  the  star-fish  is  very  dilatable, 
so  as  to  admit  large  mollusca  in  their  entire 


38 


ECHINODERMATA. 


shell.  The  gullet  and  part  of  the  stomach  are 
usually  everted,  protruded,  and  applied  round 
the  object  to  be  swallowed,  which  is  then  drawn 
in.  The  hard  or  indigestible  matters,  such  as 
the  shells  of  mollusca,  are  discharged  by  the 
mouth.  The  star-fish  is  said  to  be  very  de- 
structive to  oyster-beds,  and  is  popularly  be- 
lieved to  suck  the  animals  out  of  their  shells. 
Bishop  Sprat,  in  his  History  of  the  Royal 
Society,  informs  us  that  great  penalties  are 
laid  by  the  Admiralty  Court  upon  those  en- 
gaged in  the  oyster-fishery  who  "  do  not  tread 
under  their  feet  or  throw  upon  the  shore  a  fish 
which  they  call  a  Five-finger,  resembling  a 
spur-rowel,  because  that  fish  gets  into  the 
oysters  when  they  gape,  and  sucks  them  out." 
Tiedemann  found  the  coeca  to  contain  a  grey- 
ish-white fluid  which  he  supposed  to  be  di- 
gested aliment ;  others  again,  such  as  Meckel, 
regard  the  coeca  as  secreting  organs,  analogous 
to  die  biliary  organs  of  many  invertebrate  ani- 
mals, with  which,  it  must  be  allowed,  they 
agree  in  several  respects. 

b.  The  mouth  of  the  Echinus  is  an  orifice 
situated  in  the  middle  of  the  circular  mem- 
brane which  fills  up  the  lower  aperture  of  the 
shell  (fig. 15,  a.)  The  points  of  the  five  teeth 
are  seen  within  it,  and  at  no  great  distance 
from  its  circumference  the  ten  tubular  tentacula 
(d)  are  observable,  which  have  been  already 
described.  The  teeth  are  set  in  five  moveable 
sockets  or  jaws  which  surround  the  commence- 
ment of  the  gullet,  and  with  the  addition  of 
some  accessory  pieces  form  the  singular  struc- 
ture usually  named  Aristotle  s  lantern.  The 
lantern  (Jigs.  10, 17, and  18)  has  the  appearance 
of  a  five-sided  pyramid  placed  with  its  apex 

Fig.  ir. 


Dental  apparatus  of  ihe  Sea-vrdiin  viewed 
,    from  above. 


downwards  or  towards  the  mouth,  the  gullet 
(«)  rising  through  its  centre.  It  is  made  up  of 
five  smaller  hollow  pyramids  (It,)  which  are  the 
sockets  of  the  teeth.  Each  lesser  pyramid  is 
three-sided ;  its  external  side  (fig.  18,  A',) 
which  forms  one  of  the  faces  of  the  greater 
pyramid,  presents  an  opening  in  its  upper 
half  which  is  closed  by  membrane  ;  its  lateral 
faces  (fig.  18,  h,  A,)  are  applied  to  the  cor- 
responding sides  of  the  adjacent  sockets,  with 
which  they  are  connected  by  short  muscular 
fibres  (p);  they  approach  each  other  at  the  inner 


Fig.  18. 


A,  two  sockets  with  teeth,         B,  single  socket  with 
of  Echinus  esculentus.  its  tooth  viewed  on 

the  outside. 

edge  of  the  socket,  but  do  not  meet.  The 
tooth  (f)  is  prismatic,  very  long,  and  lodged 
in  a  groove  formed  in  the  external  side  of  the 
socket ;  its  point  projects  beyond  the  apex  of 
the  socket;  its  opposite  extremity  or  root  rises 
above  the  base,  where  it  is  bent  inwards  and 
downwards  and  inclosed  in  a  membrane.  The 
teeth  are  very  hard  at  the  point,  but  softer 
towards  the  root,  where  they  are  easily  sepa- 
rable into  transverse  scales  or  plates  with  a 
fine  silky  or  asbestine  lustre;  they  seem  to 
grow  continually  at  the  root,  and  wear  at  the 
point  as  in  the  Rodentia. 

Ten  additional  pieces  contribute  to  form  the 
lantern.  Five  of  these  (i)  are  oblong  and 
flattened,  and  are  placed  horizontally,  in  a  ra- 
diating manner,  on  the  upper  surface  of  the 
lantern,  occupying  the  intervals  between  the 
bases  of  the  lesser  pyramids.  The  other  five 
(k)  are  placed  directly  over  the  first ;  they  are 
longer  but  more  slender,  and  bent  in  a  semi- 
circular form,  the  convexity  being  upwards ; 
their  central  ends  are  articulated  with  the  cor- 
responding extremities  of  the  horizontal  pieces ; 
the  outer  ends  are  bifid  and  give  attachment  to 
ligaments. 

The  muscles  and  ligaments  belonging  to  the 
dental  apparatus  partly  pass  between  its  dif- 
ferent pieces,  and  partly  connect  it  with  the 
border  of  the  shell.  It  will  be  recollected  that 
the  border  of  the  shell  forms  five  processes 
(figs.  1 0  and  17,  g,g,  g,)  which  rise  in  the  form 
of  arches  into  its  cavity  round  the  lower  aper- 
ture. Ten  muscles  (m,  m,)  arise  from  these 
arches,  and  descending  inwardly  are  inserted 
into  the  lesser  pyramids  or  sockets  near  the 
point.  Two  of  these  muscles  come  from  every 
arch,  and  diverging  are  inserted  into  different 
pyramids,  so  that  each  pyramid  receives  its 
two  muscles  in  a  converging  manner  from  two 
adjacent  arches.  The  muscles  described  draw 
outwards  the  sockets  separating  them  and 
widening  the  mouth.  Other  ten  muscles  (n,  n,) 
arise  in  pairs  from  the  border  of  the  shell  in 
the  intervals  of  the  arches,  and,  ascending,  are 
inserted  into  the  outer  surface  of  the  sockets 
near  their  base,  each  socket  receiving  a  pair. 
These  are  antagonists  to  the  last  described ; 
they  move  the  points  of  the  pyramids,  and 
consequently  the  teeth  inwards  and  against 
each  other.    Five  muscles  composed  of  short 


ECHINODERMATA. 


39 


transverse  fibres  (p,  fig.  18,)  unite  the  lateral 
surfaces  of  the  sockets,  and  serve  to  approxi- 
mate them,  acting  collectively  as  a  sort  of 
sphincter,  and  as  antagonists  to  those  first  de- 
scribed. Lastly,  five  muscles  (figs.  10  and  17, 
o,  o,  o,)  pass  between  the  semicircular  pieces 
on  the  upper  part  of  the  lantern.  Besides  the 
muscles  described,  there  are  ten  very  thin 
whitish  bands  (s,  s,)  which  arise  in  pairs  from 
the  external  forked  extremities  of  the  semi- 
circular pieces,  and  are  inserted  into  the  border 
of  the  shell  in  the  intervals  between  the  arches. 
Tiedemann  describes  these  bands  as  muscles ; 
Meckel,  on  the  other  hand,  considers  them  as 
ligaments ;  in  the  E.  esculentus  they  certainly 
seem  to  us  to  be  ligamentous.  Two  liga- 
mentous filaments  pass  from  the  central  end  of 
every  semicircular  piece  to  the  gullet.  A  co- 
vering of  the  peritoneum  envelopes  the  dental 
apparatus,  extending  to  it  from  the  border  of 
the  shell. 

The  oesophagus  (fig.  19,  a,)  rises  through 
the  lantern,  to  which  it  is  connected  by  fine 
ligaments,  and  after  a  few  curvatures  termi- 
nates in  a  wider  part  of  the  alimentary  canal, 
somewhat  in  the  same  way  as  the  small  intes- 
tine joins  the  great  in  the  human  body.  The 
wider  portion  (b,  b,)  of  the  canal  turns  twice 
round  the  inside  of  the  shell  in  a  waving 
manner,  and  terminates  at  the  anus  (c).  In 


Fig.  19. 


Internal  view  of  Echinus  sexatilis. 
A,  under  half;  B,  upper. 


its  second  or  superior  circuit  it  changes  to  an 
opposite  direction,  but  its  flexures  in  both  cir- 
cuits are  parallel.  The  tissue  of  the  alimentary 
canal  is  very  delicate,  the  external  tunic  is 
formed  by  the  peritoneum,  which  attaches  the 
intestine  by  a  mesentery  to  the  shell,  lines  the 
inside  of  the  latter,  and  is  reflected  over  the 
ovaries  and  the  lantern.  The  inner  coat  of  the 
intestine  is  soft  and  of  a  brownish-yellow  co- 
lour; between  it  and  the  external,  Tiedemann 
states  that  delicate  longitudinal  and  circular 
muscular  fibres  are  distinguishable. 

The  Echini  are  generally  believed  to  feed  on 
mollusca  and  Crustacea,  and  in  corroboration 
of  this,  Tiedemann  states  that  he  has  found  in 
the  Echinus  sexatilis  small  univalve  and  bivalve 
shells  entire  among  the  excrements,  besides 
fragments  of  larger  ones.  Blainville,*  on  the 
other  hand,  could  never  find  any  thing  else 
than  sand  in  the  alimentary  canal,  and  he  re- 
marks that  the  general  opinion  as  to  the  carni- 

i  *  Diet,  des  Sc.  Nat.  art.  Oursin. 


vorous  habits  of  the  sea-urchin  is  probably 
more  an  inference  from  the  structure  of  the 
teeth  and  jaws  than  the  result  of  observation  ; 
he,  however,  adds  that  M.Bosc  had  witnessed 
an  echinus  in  the  act  of  seizing  and  devouring 
a  small  crustaceous  animal.  In  the  intestine 
of  the  E.  esculentus  we  have  usually  found 
numerous  small  morsels  of  sea-weed,  for  the 
most  part  encrusted  with  a  flustra.  The  excre- 
ments, which  are  in  the  form  of  small  round 
pellets  about  the  size  of  peppercorns,  consist 
chiefly  of  sandy  matter  with  fragments  of  shells, 
but  it  would  be  difficult  to  say  whether  these 
are  the  remains  of  digested  mollusca  or  merely 
a  portion  of  the  usual  testaceous  debris  so 
abundant  in  sand  and  mud. 

The  principal  difference  of  the  alimentary 
organs  in  the  different  genera  of  Echinida  de- 
pends on  the  position  of  the  anus  and  the 
presence  or  absence  of  teeth.  In  Scutella, 
Clypeaster,  Fibularia,  Echinoneus,  Galerites, 
Ananchites,  and  Spatangus,  the  anus  as  well 
as  the  mouth  opens  on  the  under  surface.  In 
Echinus,  Cidaris,  Cassichda,  and  Nucleolites, 
it  is  situated  on  the  upper  surface ;  in  the  first 
two  exactly  in  the  centre,  in  the  last  two  at  a 
greater  or  less  distance  from  it.  The  teeth  are 
wanting  in  Spatangus  and  Cassidula. 

c.  The  alimentary  canal  of  the  Holothuria  is 


Fig.  20. 


Hulothuria  tubulosu  :  alimentary  canal  and  blood* 
vessels. 

The  respiratory  organ,  c,  c,  is  cut  short. 


40 


ECHINODERMATA. 


very  simple  (fig.  20,  e,f,  g,  h.) 
At  the  mouth  it  is  surrounded  by 
the  tentacula  and  calcareous  ring 
already  described,  it  passes  back- 
wards on  the  right  side  the  whole 
length  of  the  body  (from  e  to/,) 
then  bending  forwards  it  returns 
to  near  the  mouth  (from  f  to  g,) 
and  at  last  runs  back  again  to  the 
posterior  extremity  (from  g  to  A,) 
where  it  terminates  in  a  short  and 
wide  cloacal  cavity  (d),  common 
to  it  and  the  respiratory  organ, 
and  opening  externally  at  the 
anus.  The  intestine  is  fixed  by  a 
mesentery,  and  the  cloaca  is  con- 
nected to  the  parietes  of  the  body 
by  numerous  muscular  bands  de- 
rived from  the  transverse  muscles. 
The  coats  of  the  canal  are  thin ; 
Tiedemann  enumerates  three,  an 
external  derived  from  the  perito- 
neum, a  middle  which  is  very  vas- 
cular and  contains  muscular  fibres, 
and  an  internal  or  mucous.  In 
H.  tubulosa  a  small  part  of  the 
canal  near  its  commencement  is 
wider  than  the  rest,  has  thicker 
coats,  and  is  more  decidedly  mus- 
cular; Tiedemann  regards  this 
part  as  the  stomach.  In  H.  pentactes,  the  part 
immediately  succeeding  the  oesophagus  and  ex- 
tending nearly  to  the  first  flexure,  is  somewhat 
cellular  and  at  the  same  time  wider,  but  thin- 
ner in  its  coats  than  the  rest  of  the  canal ; 
this  part  is  considered  to  be  the  stomach  by 
Meckel. 

It  is  a  singular  fact,  which  it  appears  was 
first  noticed  by  Iledi,  that  several  species  of 
Holothuria,  on  being  taken  from  the  sea  and 
put  into  a  vessel  of  sea-water,  discharge  their 
intestine  and  part  of  the  respiratory  organ 
through  the  anus.  This  operation  is  effected 
by  repeated  contractions  of  the  cutaneous 
muscles,  and  some  naturalists  are  disposed  to 
regard  it  as  a  voluntary  act. 

4.  Respii'atory  organs. — The  Echinodermata 
breathe  through  the  medium  of  sea-water.  In 
the  star-fish  and  urchin  the  water  enters  the 
body,  passing  into  the  space  in  which  the 
viscera  are  lodged,  and  this  cavity,  which,  as 
already  stated,  is  lined  by  a  peritoneal  mem- 
brane and  occupies  the  greater  part  of  the 
body,  is  generally  regarded  as  the  chief  seat  of 
the  respiratory  process.  In  the  Holothuria  the 
water  is  alternately  drawn  in  and  expelled  from 
a  tubular  respiratory  organ  ramified  within  the 
body. 

a.  In  the  star-fish  the  water  is  generally  be- 
lieved to  enter  and  issue  from  the  body  by 
numerous  small  tubes  on  the  surface,  which 
have  accordingly  been  named  the  respiratory 
tubes.  These  are  very  small,  membranous,  and 
in  figure  somewhat  conical  (fig.  298,  c,  c, 
p.  615,  vol.  i.);  they  communicate  at  their 
base  with  the  interior  of  the  body,  and  are 
perforated  at  the  summit  by  an  orifice  which 
can  be  very  accurately  closed.  Most  of  them 
are  placed  in  groups  or  patches,  and  opposite 


Fig.  21. 


Portion  of  the  shin  of  Asterias  rubens,  seen  on  the  inside  and  magnified, 
c,  c,  peritoneal  membrane  raised. 

each  group  the  fibrous  membrane  forming  the 
wall  of  the  body  presents  on  its  inside  a  shal- 
low pit  (fig.2l,  a;  fig. 298,  vol.  i.  e;  fig.  16,  s,s,) 
perforated  with  holes,  through  which  the  tubes 
communicate  with  the  internal  cavity.  The 
tubes  are  formed  externally  of  the  superficial 
layer  of  the  skin,  and  are  lined  in  the  inside 
by  a  prolongation  of  the  peritoneal  membrane. 
This  membrane  lines  the  parietes  of  the  body, 
and  is  reflected  over  the  contained  parts;  at 
least  it  covers  the  stomach  and  caeca,  and  pro- 
bably also  the  ovaries  and  vesicles  of  the  feet; 
opposite  the  perforated  pits  it  sends  prolonga- 
tions (b,  b,)  through  the  holes  into  the  tubes, 
as  may  be  easilv  seen  on  stripping  off"  a  portion 
of  it. 

There  can  be  no  doubt  that  sea-water  enters 
the  peritoneal  cavity.  The  animal  slowly  dis- 
tends itself  with  that  fluid,  and  again,  but  at 
no  stated  interval,  gives  out  a  portion  of  it: 
this  is  obvious  from  the  fact  that  the  same 
animal  may  be  seen  distended  at  one  time  and 
flaccid  at  another.  Naturalists  are  generally  of 
opinion  that  the  water  enters  and  issues  by  the 
respiratory  tubes,  and  indeed  no  other  orifices 
have  been  discovered;  we  must,  however, 
freely  own  that  we  have  never  been  able 
actually  to  observe  its  passage  through  these 
tubes. 

The  peritoneal  membrane  seems  to  be  the 
principal  seat  of  respiration ;  spread  over  the 
viscera  and  the  parietes  of  their  containing 
cavity,  and  lining  the  respiratory  tubes,  it  pre- 
sents a  great  extent  of  surface  continually  in 
contact  with  the  surrounding  medium  ;  and  we 
have  found  that  a  beautiful  provision  exists  for 
maintaining  currents  of  water  along  the  mem- 
brane, and  thus  effecting  that  constant  reno- 
vation of  the  fluid  in  contact  with  its  surface 


ECHINODERMATA. 


41 


which  is  required  in  the  respiratory  process. 
These  currents  are  produced  by  means  of  cilia ; 
they  are  more  particularly  described  in  the 
article  Cilia,  to  which  we  refer  the  reader. 
Ciliary  currents  take  place  also  on  the  external 
surface  of  the  body,  which  probably  partakes 
in  the  process  of  respiration  ;  we  have  more- 
over observed  them  within  the  tubular  feet 
and  on  the  internal  surface  of  the  stomach  and 
cceca;  in  this  last  situation  they  are  probably 
subservient  to  digestion,  but  their  use  is  more 
fully  considered  in  the  article  referred  to. 

b.  The  respiratory  system  of  the  sea-urchin 
is  very  similar.  The  water  enters  the  body 
through  membranous  respiratory  tubes,  which 
are  collected  into  ten  small  bunches  (Jig.  15, 
e,  e),  situated  on  the  under  surface  of  the 
animal  at  the  border  of  the  shell,  and  opening 
internally  by  ten  perforated  pits  like  those  of 
the  Asterias.  The  fluid  being  introduced  into 
the  peritoneal  cavity,  is  moved  along  its  parietes 
and  over  the  surface  of  the  alimentary  canal, 
the  ovaries  and  the  vascular  laminre  of  the 
feet,  by  the  action  of  cilia.  Ciliary  currents 
have  also  been  observed  on  the  external  surface 
of  the  body. 

c.  The  respiratory  organ  of  Holothuria  (Jig. 
34,  /,  /',  h,  p.  109,  vol.  i.)  has  some  resem- 
blance in  form  to  that  of  air-breathing  animals. 
It  is  a  very  long  membranous  sac,  placed 
within  the  body,  which  opens  into  the  cloaca 
near  the  rectum  and  extends  forwards  from 
thence  nearly  the  whole  length  of  the  body, 
either  single,  or  (as  in  Holothuria  tubulosa) 
divided  into  two  main  branches  (Jig.  20,  c,  c, 
cut  short,  Jig.  34,  f,f,  p.  109,  vol.  i.),  which 
in  the  vicinity  of  the  cloaca  are  joined  by  a 
short  common  stem.    One  of  these  branches 
is  intimately  connected  by  bloodvessels  to  the 
intestine,  the  other  by  muscular  fasciculi  to 
the  parietes  of  the  body.     The  sac,  whether 
single  or  bifid,  gives  off  a  great  many  lateral 
branches,  which  after  successive  divisions  ter- 
minate in  shut  or  blind  extremities.  Both 
stem  and  branches  contain  distinct  circular  and 
longitudinal  muscular  fibres,  and  contract  on 
being  irritated.    In  the  act  of  respiration  sea- 
water  is  drawn  into  and  expelled  from  this 
organ,  and  its  entrance  and  exit,  which  may 
be  readily  seen  at  the  cloaca,  occur  in  some 
species  so  often  as  once,  twice,  or  even  three 
times  in  a  minute.    The  alternate  inhalation 
and  expulsion  of  the  fluid  are  effected  partly 
by  the  action  of  the  muscular  parietes  of  the 
body,  but  principally,  it  would  appear,  by  the 
muscular  fibres  of  the  organ  itself,  for  Tiede- 
mann  observed   the  process  still  to  go  on, 
though   with   diminished  activity,  when  the 
animal  was  cut  open  and  the  organ  exposed. 
Cuvier  states  that  the  sac  in  some  species  is 
without  branches. 

5.  Vascular  system. — A  system  of  vessels 
for  the  circulation  of  the  blood  exists  in  the 
animals  under  consideration.  The  tenuity  of 
their  coats,  however,  and  pale  colour  of  their 
contents  render  it  extremely  difficult  to  trace 
completely  the  distribution  of  these  vessels, 
and  we  accordingly  find  that  the  descriptions 
of  them  given  by  Tiedemann  and  Delle  Chiaje, 


the  principal  authorities  on  the  subject,  differ 
materially  from  each  other.     According  to 
Tiedemann  the  proper  sanguiferous  system  is, 
in  its  distribution,  in  a  great  measure  confined 
to  the  alimentary  organs  and  ovaries,  or  to 
these  and  the  respiratory  organ  where  such  is 
present ;  he  therefore  supposes  that  the  canals 
which  convey  the  fluid  of  the  feet  serve  more- 
over as  nutritious  vessels  to  parts  of  the  body 
also  supplied  by  the  sanguiferous  system.  In 
short  he  conceives  that  there  are  two  systems  of 
nutritious  vessels  distinct  from  each  other,  the 
sanguiferous  system,  confined  to  certain  organs 
already  named,  and  the  vessels  of  the  feet, 
destined  to  nourish  another  set  of  parts ;  the 
vessels  of  the  first  system  carrying  blood, 
those  of  the  second  a  nutritious  fluid  secreted 
from  the  blood.    Delle  Chiaje  on  the  other 
hand  maintains  that  the  two  orders  of  vessels 
communicate  together  and  form  but  one  sys- 
tem.   From  our  own  observations   on  the 
Asterias  we  are  disposed  to  conclude  that  the 
vessels  of  the  feet  form  a  system  apart  from 
the  bloodvessels,  as  is  maintained  by  Tiede- 
mann ;  but  there  seems  considerable  reason  to 
doubt  whether,  as  that  author  supposes,  they 
serve  as  the  nutritious  vessels  of  the  parts  in 
which  they  run ;  for  even  according  to  his  own 
admirable  description  it  does  not  appear  that 
they  ramify  in  the  tissues,  if  we  except,  perhaps, 
the  skin  of  the  Holothuria.    Moreover  their 
contained  liquid  does  not  present  the  usual 
characters  of  blood  or  of  a  fluid  adapted  to 
nourish  the  textures ;  it  is  true  there  are  float- 
ing particles  suspended  in  it,  but  the  clear 
fluid  when  filtered  yields  no  trace  of  animal 
matter,  but  agrees  almost  entirely  in  com- 
position with  sea-water;  at  least  such  is  the 
result  of  our  examination  of  it  in  the  Asterias. 
The  vessels  of  the  feet  having  been  already  de- 
scribed, we  have  here  only  to  give  an  account  of 
the  proper  sanguiferous  system,  following  Tiede- 
mann as  our  leading  authority,  but  at  the  same 
time  stating  the  more  material  points  in  which 
Delle  Chiaje  differs  from  him. 

a.  In  Asterias  a  delicate  vessel  runs  along 
the  upper  surface  of  each  of  the  cceca.  There 
are,  of  course,  ten  such  vessels  in  Asterias 
aurantiaca  (from  which  the  description  is  taken) 
corresponding  in  number  with  the  cceca 
(Jig.  22,  v,  v).  They  commence  near  the 
extremity  of  trie  rays,  and,  receiving  branches 
from  the  branches  and  lobes  of  the  coeca, 
proceed  to  the  central  part  of  the  animal,  where 
they  terminate  in  a  circular  vessel  (x)  which 
runs  round  the  upper  part  of  the  body  on  the 
internal  surface.  The  circular  vessel  also  re- 
ceives ten  branches  (y,y)  from  the  ovaries, 
and  five  from  the  stomach,  which  before  joining 
it  unite  into  two  (w).  The  vessels  described 
seem  to  constitute  the  venous  system,  and 
Tiedemann  further  supposes  that  the  ccecal  and 
gastric  veins  convey  the  chyle  or  nutritious 
part  of  the  food  from  the  alimentary  organs. 
The  circular  vein  opens  into  a  vertical  canal 
(h,  and  fig.  12,  h),  which  descends  along  the 
prominent  angle  between  two  rays,  inclosed 
in  the  same  membranous  sheath  with  the  sand 
canal  already  described,  and  terminates  in  an 


42  ECHINODERMATA, 


Asterias  aurantiaca  opened  from  above. 

A,  ray  with  thn  cceca  g,  g,'m  their  place.  B,  coeca  removed  ;  vesicles  of  feet  d,  seen.  C,  vesicles  of 
feet  removed  to  shew  the  calcareous  segments  of  the  ray.  D,  skin  forming  roof  of  the  body 
and  rays  A,  B,  C,  raised  ;  vessels  seen  on  its  inner  surface  with  collapsed  stomach,/,  &c. 


inferior  circular  vessel.  The  descending  canal 
is  dilated  in  the  middle ;  its  comparatively 
thick  brown  coloured  parietes  are  smooth 
externally,  but  reticulated  on  the  inside  and 
composed  of  interlaced  fibres,  which  Tiede- 
mann  found  to  possess  muscular  irritability. 
He  accordingly  considers  this  canal  as  the 
heart.  The  inferior  circular  vessel  (which 
must  not  be  confounded  with  the  circular 
canal  connected  with  the  feet)  surrounds  the 
mouth  on  the  outside  or  inferior  surface ;  it 
sends  out  five  branches  which  pass  into  the 
interior  of  the  body,  and  are  distributed  to  the 
stomach,  coeca  and  ovaries.  Tiedemann  re- 
gards these  branches  with  the  circular  vessel 
from  which  they  proceed  as  arteries,  and  he 
thinks  it  probable  that  their  minute  ramifica- 
tions open  into  the  radicles  of  the  veins, 


though  from  their  delicacy  he  has  not  been 
able  to  ascertain  the  fact  by  injection. 

Tiedemann's  view  of  the  function  of  the 
respective  vessels  is  derived  solely  from  a  con- 
sideration of  their  anatomical  disposition,  and 
while  in  the  same  way  it  may  be  inferred  that 
the  blood  circulates  in  a  direction  conformable 
with  this  view,  it  must  nevertheless  be  kept  in 
mind  that  no  direct  physiological  proof  of 
such  a  course  of  the  blood  has  been  yet  ob- 
tained. Besides  the  vessels  described,  Tiede- 
mann found  yet  another  circular  vessel  sur- 
rounding the  mouth  on  the  under  surface  and 
placed  more  superficially  than  the  last  men- 
tioned ;  it  is  of  an  orange  colour  and  sends  a 
branch  along  each  of  the  rays,  in  the  groove 
which  is  on  the  middle  of  their  inferior  sur- 
face.   He  could  trace  no  connection  between 


ECHINODERMATA. 


43 


this  vessel  or  its  branches  and  the  rest  of  the 
vascular  system,  and  he  professes  himself  at  a 
loss  to  conjecture  what  may  be  its  function. 

According  to  Delle  Chiaje  the  circular  ves- 
sel (i,  i,  Jigs. 12  and  22,)  into  which  the  canals  of 
the  feet  open  receives  also  the  veins  from  the  up- 
per surface  of  the  cceca  and  stomach.  The  same 
vessel,  which  he  names  the  venous  sinus,  gives 
out — 1 .  twenty  short  dental  arteries ;  2 .  the  mesa- 
raics  to  the  under  surface  of  the  cceca;  3.  five 
vertebral  arteries  which  open  into  the  vesicles 
of  the  feet;  4.  the  radial  to  the  under  part  of 
each  ray ;  5.  the  dorsal  arteries  to  the  upper 
part  of  the  ray,  which  extend  their  ramifications 
to  the  external  surface  of  the  body. 

b.  Echinus.     A  circular  vessel,  supposed 
to  be  of  a  venous  nature,  surrounds  the  anal 
extremity  of  the  intestine  (fig.  19,  at  c),  being 
situated  on  the  internal  surface  of  the  shell. 
A  vertical  vessel  (e,  cut  short)  descends  from 
it  towards  the  lantern  and  opens  into  a  short 
oval  canal  (h)  with  muscular  parietes,  which 
exhibits  during  life  slow  but  distinct  contrac- 
tions and  dilatations,  and  which  is  therefore 
considered  as  a  heart.     The  heart  is  situated 
near  the  commencement  of  the    intestine ; 
a  vessel  (i,  i,  i,  i)  issues  from  it  which  first 
sends  branches  to  the  oesophagus   and  the 
muscles  and  membranes  of  the  lantern,  and 
then  runs  along  the  whole  intestine  on  its  inner 
border,  first  increasing  somewhat  in  diameter, 
afterwards  gradually  diminishing   as    it  ap- 
proaches the  anus,  where  it  terminates.  This 
vessel  gives  off  at  all  points  of  its  course  small 
branches  to  the  intestine ;  it  contains  a  dark 
yellow  fluid  coagulable  by  alcohol,  and  its 
parietes   contract   on    mechanical    irritation ; 
Tiedemann  conceives  it  to  be  an  artery.  Ano- 
ther vessel  (A',  k,  k,  k)  equal  in  length  to  the 
last  described,  but  not  directly  connected  with 
the  heart,  runs  along  the  intestine  on  its  outer 
or  mesenteric  border;  it  also  is  widest  in  the 
middle  of  its  course,  fiom  whence  it  may  be 
traced  in  one  direction  as  far  as  the  lantern, 
and  in  the  other  to  the  vicinity  of  the  anus. 
Along  its  whole  course  this  vessel  receives 
small  branches  from  the  intestine,  and  gives 
off  branches  from  its  other  side,  which  pass 
along  the  mesentery  to  the  internal  surface  of 
the  shell,  and  are  ramified  on  the  lining  or 
peritoneal  membrane.    Tiedemann  regards  this 
vessel  as  a  vein  ;  but  as  it  does  not  directly 
communicate  with  either  the  heart  or  the  cir- 
cular vessel,  he  conceives  that  the  fluid  which 
it  circulates  is  conveyed  into  it  by  one  set  of 
branches,  and  out  of  it  by  the  other,  the  in- 
testinal being  its  entering  and  the  mesenteric 
or  peritoneal  its  issuing  branches.    Lastly,  the 
circular  vessel  placed  round  the  termination  of 
the  intestine  receives  several   vessels  which 
come  from  the  peritoneal  lining  of  the  shell, 
and  whose  commencing  branches  are  probably 
continuous  with  the  terminations  of  the  peri- 
toneal branches  from  the  longitudinal  vein. 
Tiedemann  conceives  the  circulation  to  take 
place  in  the  following  manner.    The  blood 
passes  from  the  circular  vessel  into  the  heart ; 
it  is  then  propelled  along  the  artery  and  its 
branches ;  from  these  it  passes  into  the  veins 


of  the  intestine,  which  also  absorb  the  chyle, 
and  the  mixed  fluid  is  conveyed  into  the  great 
longitudinal  vein;  it  next  passes  into  the 
branches  of  this  vessel,  which  are  distributed 
to  the  lining  membrane  of  the  shell,  and  is  at 
last  conveyed  back  by  another  set  of  vessels 
into  the  circular  vein,  from  which  we  have 
supposed  it  to  set  out.  That  this  is  the  course 
of  the  circulation  is  inferred  from  the  anatomy 
of  the  circulating  organs.  On  similar  grounds 
Tiedemann  with  great  probability  supposes  that 
the  blood  undergoes  its  respiratory  change, 
at  least  chiefly,  in  its  passage  through  the 
vessels  of  the  peritoneal  membrane,  being 
there  most  effectually  exposed  to  the  influence 
of  the  water;  he  accordingly  compares  the 
branches  of  the  great  vein  which  ramify  on 
that  membrane  to  pulmonary  or  branchial 
arteries,  and  the  vessels  which  return  the  blood 
to  the  circular  vein,  together  with  that  vein 
itself,  to  pulmonary  veins.  He  found  that  the 
fluid  contained  in  the  longitudinal  vein  was 
of  a  yellowish  white  colour,  from  which  cir- 
cumstance, as  well  as  from  the  fact  that  he 
could  discover  no  special  chyliferous  vessels, 
he  inferred  that  the  chyle  was  absorbed  by  its 
intestinal  branches.  This  vein  did  not  con- 
tract on  the  application  of  stimuli. 

Delle  Chiaje's  description  of  the  vessels 
of  the  Echinus  is  in  substance  as  follows.  An 
annular  vessel  surrounds  the  oesophagus ;  it 
receives  the  termination  of  the  intestinal  vein, 
and  gives  out  the  intestinal  artery,  which  like 
the  vein  runs  along  the  intestine,  and  also  five 
oesophageal  arteries,  which  before  ramifying  on 
the  mouth  communicate  (by  means  of  a  branch 
passing  between  the  muscles  of  the  teeth)  with 
the  dorsal  arteries.  These  last  are  the  canals 
of  the  feet;  they  run  along  the  ambulacra  to 
the  anus,  where,  according  to  Delle  Chiaje, 
they  form  a  ring,  and  in  their  course  send 
lateral  branches  into  the  feet. 

c.  Holothuria.  A  vessel  (Jig.  20,  i,  i,  i,  i,), 
which  Tiedemann  conceives  to  be  the  great 
artery,  runs  along  the  free  border  of  the  intes- 
tine. It  is  widest  in  the  middle,  and  gradually 
disappears  posteriorly  in  the  neighbourhood  of 
the  cloaca,  while  anteriorly  it  forms  an  annular 
vessel  (at  e)  round  the  stomach,  out  of  which 
branches  proceed  to  the  stomach,  the  ovaries 
and  the  sac  connected  with  the  canals  of  the 
feet  and  ten  taenia  formerly  described.  A  short 
but  wide  anastomosing  branch  (cut  at  k,  k,) 
passes  from  the  artery  about  the  middle  of  the 
first  portion  of  the  intestine,  to  join  it  again  at 
the  middle  of  the  second  portion  (m),  that  is, 
nearly  about  the  middle  of  the  arterial  trunk 
itself.  Slow  contractions,  followed  by  dilata- 
tions, were  observed  by  Tiedemann  in  this 
vessel ;  they  commenced  at  the  middle  or 
widest  part,  and  proceeded  in  opposite  direc- 
tions to  its  two  extremities,  carrying  on  the 
light  brown-coloured  blood  contained  within  it 
in  a  corresponding  manner.  The  main  artery, 
which  seems  thus  also  to  serve  the  purpose  of 
a  heart,  sends  in  its  course  numerous  branches 
to  the  intestine,  from  these  the  blood  is  received 
by  the  commencing  veins,  which,  uniting  to- 
gether at  the  opposite  or  attached  border  of  the 


44 


EC  HI  NOD  ERM  ATA. 


intestine,  form  a  plexus  along  its  first  portion, 
whose  branches  ultimately  terminate  in  a  large 
longitudinal  venous  trunk  (n,  n,  n,  n).  The 
blood  is  conveyed  from  this  great  vein  to  the 
right  branch  of  the  respiratory  organ,  (which 
lies  between  the  first  and  second  portions  of 
intestine,)  by  a  considerable  number  of  vessels 
which  divide  like  arteries  into  smaller  ramifi- 
cations on  the  lung,  and  may  therefore  be  com- 
pared to  pulmonary  arteries.  The  capillary 
branches  of  these  vessels  transmit  the  blood 
into  the  commencing  pulmonary  veins,  which, 
uniting  into  larger  and  larger  branches,  ter- 
minate in  a  third  longitudinal  vessel  (t>), 
situated  on  the  second  portion  of  intestine. 
This  last-mentioned  vessel,  which  may  be  con- 
sidered as  the  great  pulmonary  vein,  sends 
branches  on  the  intestine  which  open  into  the 
wide  part  of  the  main  artery,  and  thus  the 
blood  is  carried  to  the  place  whence  it  set  out. 
According  to  Delle  Chiaje,  the  principal  vein, 
after  diminishing  in  width,  opens  into  the 
oblong  sac  which  is  connected  with  the  vessels 
of  the  feet,  and  out  of  this  bag  six  vessels 
issue.  One  of  these  is  the  great  artery,  which 
runs  along  the  intestine ;  the  other  five  are  the 
vessels  of  the  tentacula  and  feet  previously 
described;  each  of  them  sends  four  branches 
forwards  to  the  tentacula,  and  a  long  one 
backwards  between  the  longitudinal  muscles 
to  the  vesicles  of  the  feet. 

5.  Nerves. — Tiedemann  discovered  a  nervous 
system  in  the  star-fish.  He  describes  it  (in  A. 
aurantiaca)  as  consisting  of  a  delicate  white 
cord  surrounding  the  mouth,  in  form  of  a  ring 
immediately  on  the  outside  of  the  circular 
vessel  into  which  the  heart  opens,  and  of  di- 
verging filaments  which  arise  from  the  annular 
cord  opposite  the  rays.  ( Fig.  23.)    There  are 


Fig.  23. 


c,feet ;  e,feet  cut  across  ;  f,  apertures  for  the  feet. 


three  filaments  for  each  ray;  one  runs  along 
the  under  surface  in  the  median  line,  and  ap- 
pears to  send  small  branches  to  the  feet ;  the 
other  two,  which  are  shorter,  pass  between  the 
first  and  second  segment  of  the  ray  into  the 
interior  of  the  body,  and  are  probably  distri- 


buted to  the  stomach.  Tiedemann  could  dis- 
cover no  ganglia,  but  others  describe  minute 
ganglia  as  existing  at  the  points  where  the 
diverging  filaments  originate.* 

The  Echinodermata  have  not  generally  been 
supposed  to  possess  any  other  sense  than  that 
of  touch.  Professor  Ehrenberg  has  how- 
ever recently  called  attention  to  certain  parts 
in  the  Asterias,  which  he  is  disposed  to  re- 
gard as  organs  of  vision.f  These  have  the  ap- 
pearance of  small  red  spots,  one  of  which  is  seen 
at  the  extremity  of  each  ray.  They  have  been 
long  known  to  exist  in  several  species  of  Asterias, 
but  no  one  ever  assigned  to  them  any  particular 
use  till  lately,  when  Professor  Ehrenberg,  struck 
with  their  resemblance  in  aspect  to  the  eyes  of 
Entomostraca  and  Infusoria,  conjectured  that 
they  might  be  of  the  same  nature.  He  states  that 
he  has  traced  the  long  nerve  of  the  ray  as  far 
as  the  extremity,  where  it  swells  into  a  sort  of 
ganglion  with  which  the  red  point  or  supposed 
eye  is  connected. 

In  the  Echinus  Tiedemann  observed  fine 
filaments  on  the  internal  surface  of  the  mem- 
brane which  fills  the  inferior  opening  of  the 
shell,  and  on  the  dental  apparatus  and  the 
longitudinal  vessels  of  the  feet,  from  which  he 
inferred  that  a  nervous  system  probably  existed 
in  the  Echinus  analogous  in  form  to  that  of  the 
Asterias.  In  the  same  way  he  was  led  to  sus- 
pect the  existence  of  such  a  system  in  the 
Holothuria,  though  by  dissection  he  could  make 
out  nothing  more  than  several  exceedingly 
delicate  filaments,  some  of  which  were  situated 
in  the  neighbourhood  of  the  mouth,  and  ap- 
peared to  enter  the  tentacula,  and  others  lay 
on  the  longitudinal  muscles.  Dr.  Grant  de- 
scribes a  connected  nervous  system  in  the  Echi- 
nus and  Holothuria,  but  without  mentioning 
on  whose  observations  his  description,  which 
we  here  transcribe,  is  founded.  "  A  nervous 
chord,"  he  states,  "  is  seen  round  the  oeso- 
phagus of  the  Echinus,  which  sends  delicate 
white  filaments  to  the  complicated  muscular 
and  sensitive  apparatus  of  the  mouth ;  other 
nerves  are  seen  extending  upwards  from  the 
same  oesophageal  ring,  along  the  course  of 
the  vessels  in  the  interior  of  the  abdominal 
cavity.  In  the  Holothuria  the  nervous  sys- 
tem is  extensively  developed.  Interior  to 
the  osseous  apparatus  of  the  mouth  is  a  white 
nervous  ring  around  the  oesophagus,  from 
which  nerves  pass  outwards  to  the  large 
ramified  tentacula  around  the  mouth,  and 
others  extend  upwards  along  the  course  of 
the  eight  strong  longitudinal  muscular  bands. 
Fine  white  filaments  are  likewise  seen  passing 
inwards  to  the  stomach  and  alimentary  ap- 
paratus."! In  a  recent  notice  of  some  obser- 
vations on  the  Echinus  by  M.  Van  Beneden,  it 
is  stated  that  he  distinctly  recognized  a  nervous 
collar  surrounding  the  oesophagus. 

6.  Generative  organs.  —  The  only  organs 
hitherto  discovered  in  the  Echinodermata,  which 

*  Grant's  Comparative  Anatomy,  p.  184. 
t  Miiller's  Archiv  fiir  Anatomie,  Physiologie, 
&c,  1834.  p.  577. 

X  Comparative  Anatomy,  p.  184. 


ECHINODERMATA. 


45 


can  with  certainty  be  regarded  as  belonging  to 
the  generative  system,  are  the  ovaries,  which 
are  found  in  all.  These  animals  would  there- 
fore appear  to  have  no  distinction  of  sex. 
Whether  the  concurrence  of  two  individuals  is 
in  general  necessary  for  propagation  is  uncer- 
tain ;  O.  Fabricius  affirms  it  of  the  star-fish, 
but  further  observation  would  be  required  satis- 
factorily to  establish  the  fact ;  he  says  "  con- 
greditur"  (Ast.  rubens)  "  mense  Maio,  oribus 
arete  connexis,  altera  supina."* 

a.  The  ovaries  of  Asterias  seem  to  vary  in 
number  according  to  the  species.  In  A.  rubens 
and  aurantiaca  there  are  ten,  two  being  situated 
in  each  ray,  above  the  vesicles  of  the  feet. 
Each  of  these  organs  consists  in  the  former 
species  of  an  oblong  cluster  of  ramified  tubes, 
(Jigs  A 2 and  16,  o, and  ato',  cut  short),  proceeding 
all  from  a  single  stem  by  which  the  organ  is 
fixed,  and  terminating  in  round  vesicular  dila- 
tations. In  A.  aurantiaca  the  tubes  are  not 
all  connected  by  a  single  stem,  but  form  about 
twenty  fasciculi,  each  of  which  has  a  distinct 
attachment  (jig.  22,  o,  u ). 

The  vesicles  contain  a  whitish  pulpy  sub- 
stance, with  which  they  are  more  or  less  dis- 
tended according  to  the  season  of  the  year; 
so  that  the  ovary,  varying  thus  in  size,  is  found 
to  occupy  sometimes  a  greater  at  other  times  a 
less  extent  of  the  ray,  to  the  commencement 
or  base  of  which  it  is  attached.  Tiedemann 
could  discover  no  excretory  duct  of  the  ovary; 
and  nothing  positive  is  known  as  to  the  way 
in  which  the  ova  are  formed  and  discharged 
from  the  body.  Tiedemann  conjectures  that 
they  escape  by  openings  situate  in  the  neigh- 
bourhood of  the  mouth,  in  the  angles  between 
the  rays. 

The  Ophiurahas  also  ten  ovaries,  which  do 
not  lie  in  the  rays,  but  in  the  central  part  of 
the  animal,  and  which,  according  to  Meckel, 
open  externally  by  orifices  on  the  ventral  sur- 
face. 

b.  The  Echinus  has  five  ovaries,  (fig.  10,  c,) 
attached  to  the  inside  of  the  shell  in  the  upper 
part  of  the  body,  and  occupying  the  spaces 
between  the  five  rows  of  feet.  They  are  often 
joined  together  laterally.  They  consist  of  an 
assemblage  of  small  round  bodies,  which  are 
the  ova.  Five  short  tubular  oviducts  come 
from  the  upper  end  of  the  ovaries  and  open 
externally  by  an  equal  number  of  orifices, 
pierced  in  five  oval  plates  which  surround  the 
anus.  The  size  of  these  organs,  as  in  the  star- 
fish, varies  much  according  to  the  degree  of 
maturity  of  the  ova.  The  ovary,  or  row  as  it 
is  named,  is  the  part  used  as  food.  Mr.  Pen- 
nant states  that  the  E.  esculentus  is  "  eaten  by 
the  poor  in  many  parts  of  England,  and  by 
the  better  sort  abroad ;"  in  ancient  Rome  the 
Echini  formed  a  favourite  dish  at  the  tables  of 
the  great. 

c.  The  ovary  of  Ilolothuria  tubulosa  (Jig.  34, 
m,  p.  109,  vol.  i  )  is  situated  at  the  fore  part 
of  the  body  near  the  stomach  and  first  portion 
of  the  intestine.  It  is  a  tube  with  many  clus- 
tering branches,  which  terminate  in  blind  and 

*  Fauna  Gvocnlandica,  p.  368. 


slightly  dilated  extremities.  The  main  tube  or 
oviduct  runs  forwards  along  the  stomach,  and 
opens  externally  on  the  dorsal  aspect  of  the 
body  a  little  way  behind  the  mouth.  Between 
the  insertion  of  its  branches  and  its  external 
orifice,  eight  or  ten  pyriform  vesicles  open  into 
it,  close  to  each  other,  by  long  tubular  pedi- 
cles. 

The  size  of  the  ovary  varies  excessively  at 
different  periods  ;  its  branches  usually  contain 
a  whitish  fluid ;  but  Tiedemann  states  that 
about  the  end  of  October  he  has  in  some  in- 
stances found  the  organ  enlarged  to  twice  or 
three  times  its  usual  dimensions,  and  con- 
taining oblong  brown-coloured  bodies  from 
half  a  line  to  a  line  in  length,  which  he  sup- 
poses were  eggs  or  perhaps  embryos.  From  a 
statement  of  O.  Fabricius  it  would  appear  that 
the  Hoi.  pentactes  is  ovo-vivi parous  :  he  says, 
"  est  vivipara :  mense  enim  Martio  in  ilia  versus 
anum  pullum  libere  natantem,  rubicundum 
vidi."*  The  pyriform  vesicles  are  found  en- 
larged at  the  same  time  with  the  ovary  itself, 
and  Tiedemann  conjectures  they  may  be  male 
organs,  by  which  a  fecundating  fluid  is  produced 
and  applied  to  the  ova. 

7.  Regeneration  of  lost  parts. — The  star-fish 
affords  an  example  of  great  regenerating  power. 
Individuals  are  often  found  which  have  evi- 
dently sustained  the  loss  of  one  or  more  rays, 
and  in  which  new  rays,  as  yet  incomplete 
in  their  growth,  occupy  the  place  of  the 
old.  Experiments  have  been  even  purposely 
made  which  were  attended  with  the  same 
result;  but  we  are  not  aware  that  the  process 
of  regeneration  in  these  animals  has  been  care- 
fully traced  in  its  successive  steps,  or  at  least 
fully  described.  In  1741  and  42,  Messrs. 
Bernard  de  Jussieu,  Guettard,  and  Gerard  de 
Villars  made  observations  and  experiments  on 
this  subject  at  various  parts  of  the  coast  of 
France.  These  researches  were  undertaken  at 
the  request  of  M.  de  Reaumur,  who  thus  de- 
scribes them.  "  They  (M.  de  Jussieu  and 
Guettard)  brought  me  specimens  of  star-fish 
with  four  large  rays  and  a  small  one  still 
growing ;  they  found  others  with  only  three 
large  and  two  extremely  small  rays ;  others 
again  with  two  large  rays  and  three  very 
small,  and,  as  it  seemed,  very  young  ones. 
Lastly  they  more  than  once  met  with  a  single 
large  ray  from  which  four  small  ones  had 
begun  to  sprout."  After  remarking  that  the 
fact  had  been  long  familiarly  known  to  the 
fishermen,  M.  Reaumur  continues,  "  The 
portions  into  which  Messrs.  Jussieu  and  Guet- 
tard had  divided  the  animals  appeared  to  go 
on  well,  the  wounds  cicatrized  and  consoli- 
dated, but  the  experimenters  were  obliged  to 
limit  their  stay  on  the  coast  to  about  fifteen 
days ;  too  short  a  period  to  trace  the  progress 
of  a  reproduction  which  apparently  is  not 
completed  till  after  several  months,  or  perhaps 
even  upwards  of  a  year."-f 

BlBLIOGKAPH Y.— Kleinius,  Naturalis  dispositio 

*  Fauna  Groenlandica,  p.  353. 
f  Reaumur,  Memoires  pour  servir  a  l'histoire 
des  insectes,  tome  vi.  preface,  page  lx.  sq. 


46 


EDENTATA. 


Echinodermatum,  4to.  Lips.  1778.  Linkius,  De 
stellis  marinis,  fol.  Lips.  1733.  Blainville,  Diet, 
des  Sc.  Nat.  art.  Oursin.  Tiedeinann,  Anatomie 
der  Rohrenholothurie,  &c.  Heidelberg,  1820.  Eh- 
renberg,  in  Meckel's  Archiv  fur  Anat.  &c.  1834. 
Delle  Chiaje,  Memorie  sulla  storia  degli  animali 
senza  vertebre  del  regno  di  Napoli. 

(W.  Sharper/.) 

EDENTATA. — A  group  of  mammiferous 
animals,  exhibiting  no  very  distinct  general 
characters  to  indicate  any  close  mutual  affinities 
between  them,  but  agreeing  in  the  unimport- 
ant character  of  the  absence  of  incisive  teeth 
and  the  possession  of  long  claws.  They  may 
indeed  be  considered  as  consisting  of  two  very 
distinct  groups  ;  the  one  exclusively  vegetable 
feeders,  the  other  generally  insectivorous  in 
their  habits.  To  the  first  belong  the  Sloths 
( Brudypm ),  (fig.  24),  constituting  the  Tar- 
digrada  of  Illiger ;  to  the  second,  the  Ant- 
eaters  ( Myrmecophaga),  ( fig.  25),  the  Arma- 


dillos ( Dasypus),  ("^g.  26),  the  Pangolin  ( Ma- 
nis )  (fig.  27),  with  their  congeners,  and  the  re- 
cently discovered  American  fossorial  animal,  the 
Chlamyphorus,  forming  the  Edentata  proper. 
The  enormous  extinct  animal,  the  Megathe- 
rium (Jig.  28),  may  be  considered  as  an  addi- 
tional form,  and  a  very  interesting  and  impor- 
tant one,  as  it  certainly  exhibits  some  charac- 
ters which  appear  to  connect  the  Tardigrada 
and  the  true  Edentata.  The  organisation  of 
these  forms  is  so  different  as  to  require  a  se- 
parate description.  The  Ornithorynchus  and 
the  Echidna  are  necessarily  excluded  from  the 
Edentata,  with  which  they  had  been  united 
by  Cuvier  and  others,  and  form  the  group 
called  Monotremata  by  Geoffroy. 

In  the  Sloths,  the  whole  structure  is  evidently 
formed  to  enable  them  to  pass  their  life  in 
trees,  amongst  the  branches  of  which  they  con- 
stantly reside,  hanging  with  the  back  down- 
wards and  creeping  slowly  along  in  this  remark- 
able   position,    embracing   the   bough,  and 


Skeleton  of  the  Ant-eater, 


EDENTATA. 

Fig.  26. 


47 


Skeleton  of  the  Armadillo. 
Fig.  27. 


Skeleton  of  the  Mams. 
Fig.  28. 


Skeleton  of  the  Megatherium. 


stretching  out  their  hands,  which  in  the  AY  or 
Bradypus  tridactylus  are  of  great  length,  to 
enable  them  to  lay  hold  of  the  extreme  twigs, 
and  bring  them  to  the  mouth.  Their  progres- 
sion on  the  ground  is  excessively  slow  and 
awkward,  and  should  they  be  obliged  to  have 
recourse  to  it  either  from  accident  or  from 
being  forced  by  famine  to  seek  a  new  tree  on 
which  to  obtain  their  subsistence,  they  quit  it 
as  speedily  as  their  peculiar  organization  will 
permit,  and  ascend  the  nearest  tree  with  an 
awkward  attempt  at  alacrity.    The  whole  of 


their  structure  is  admirably  adapted  to  these 
extraordinary  habits;  and  although  upon  a 
comparison  of  these  slow-moving  creatures 
with  the  active  and  intelligent  and  elegant  ani- 
mals which  form  the  more  conspicuous  groups 
of  the  Edentata,  they  may  appear  to  possess 
but  few  advantages  of  structure,  and  little  to 
excite  interest  in  their  habits,  yet  a  careful 
investigation  into  the  relation  between  their 
organization  and  their  mode  of  life  will  shew 
that  not  even  in  the  most  elevated  forms  of 
the  animal  creation,  does  the  wisdom  of  the 


48 


EDENTATA. 


Creator  display  itself  more  fully  than  in  the 
construction  of  these  contemned  and  apparently 
apathetic  beings.  I  must  refer  the  reader  to 
a  highly  interesting  paper  by  Professor  Buck- 
land  in  the  Linnaean  Transactions,  in  which 
the  libels  of  Cuvier  on  this  maligned  animal 
are  beautifully  and  satisfactorily  refuted. 

The  Ant-eaters  and  Armadillos,  on  the  other 
hand,  which  may  be  considered  as  the  true 
Edentata,  are  constructed  for  very  different 
habits,  and  the  Chlurnyphorus  must  be  consi- 
dered as  offering  a  very  near  affinity  to  the 
latter  genus.  The  Ant-eaters  with  their  thick 
long  hair  and  fossorial  claws,  and  the  long  ex- 
tensile tongue  with  which  they  are  furnished, 
are  thus  enabled  to  scratch  or  dig  up  the  ant- 
hills and  to  receive  their  minute  but  multi- 
tudinous inhabitants  on  the  mucous  surface  of 
the  tongue;  whilst  by  their  long  dense  hair 
they  are  protected  from  the  annoyance  or  dan- 
ger which  their  little  troublesome  victims 
would  otherwise  inflict.  The  Armadillos  and 
the  Chlamyphorus,  on  the  other  hand,  pursue 
their  insect  prey  either  on  or  beneath  the  sur- 
face of  the  earth,  and  are  protected  from  the 
attacks  of  their  enemies  by  the  panoply  of 
mail  with  which  they  are  furnished. 

The  osseous  system.  The  cranium. — The  ge- 
neral character  which  at  once  strikes  us  in  look- 
ing at  the  cranium  of  the  Sloths  (Jig.  29)  is  its 


Fig.  29. 


Head  of  the  Sloth. 


extreme  shortness,  particularly  with  regard  to 
the  facial  portion,  and  the  roundness  of  its 
whole  contour.  In  the  insectivorous  forms 
the  muzzle,  on  the  contrary,  is  greatly  elongated. 
The  frontal  bone  in  the  Tardigrada  is  large,  and 
the  anterior  portion  convex ;  it  has  no  zygo- 
matic process,  and  the  frontal  and  orbital  por- 
tions pass  into  each  other  by  a  very  obtuse 
angle.  The  parietal  bone  in  most  is  of  a  square 
figure.    In  the  Armadillos  (fig.  30)  and  in  the 


Fig.  30. 


Head  of  the  Armadillo. 


Orycteropus  the  two  parietals  are  united  from 
an  early  period ;  in  the  Ant-eaters,  on  the  con- 
trary, they  remain  separate.  In  the  Sloth  the 
squamous  portion  of  the  temporal  bone  is  of 
large  dimensions,  and  the  acoustic  portion  of 
but  moderate  size.  The  zygomatic  process  is 
small  and  does  not  reach  the  jugal  bone ;  a  con- 
struction which  is  still  more  conspicuously 
seen  in  the  Ant-eaters.  The  occipital  bone  is 
large ;  the  squamous  portion  broad  and 
rounded,  the  superior  part  being  continued  to 
the  inferior  by  an  obtuse  angle  in  the  Sloths, 
and  by  nearly  a  right  anglein  the  true  Edentata. 
The  occipital  foramen  is  round.  The  jugal 
bone  offers  some  remarkable  peculiarities  in  its 
form.  In  the  Ant-eaters  (Jig.  31)  it  occurs  in  a 


Fig.  31. 


Head  of  the  Ant-eater. 


very  imperfect  condition,  being  merely  an  ob- 
long plate  of  bone,  terminating  posteriorly  in 
a  rounded  point,  situated  in  the  posterior  ex- 
tremity of  the  superior  maxillary  bone,  and 
beneath  the  lachrymal,  extending  posteriorly 
scarcely  beyond  the  latter ;  consequently  it  is 
remote  from  the  temporal  bone  throughout  the 
whole  length  of  the  temporal  fossa,  and  there 
is  no  zygomatic  arch.  In  the  Munis  (fig. 
32)  it  is  absolutely  wanting.    In  the  Arma- 


Fig.  32. 


Head  of  the  Manis. 


dillos  it  is  somewhat  more  fully  developed ; 
it  is  larger  and  higher  and  reaches  the  tem- 
poral bone  by  its  posterior  portion.  In  the 
Sloths,  especially  in  the  Bradypus  diJactylus, 
or  Unau,  it  attains  a  much  greater  size,  and  has 
on  its  inferior  margin  a  long  process  extending 
downwards  and  backwards  almost  to  the  base 
of  the  lower  jaw.  This  remarkable  process  is 
also  found  in  the  enormous  fossil  animal  the 
Megatherium  (Jig.  33).  The  posterior  extremity 
of  the  jugal  bone  is  remote  from  the  zygomatic 
process  of  the  temporal  in  the  Sloths,  but  in  the 
Megatherium  these  bones  are  united,  and  the 
zygomatic  arch  is  therefore  complete.  The  in- 
ferior maxillary  bone  varies  excessively  in  this 
order.  In  the  Orycteropus,  Manis,  and  Myrme- 
cophaga,  it  is  extremely  long  and  depressed  ; 
its  height  does  not  greatly  vary  in  the  whole  of 
its  length.  In  the  Armadillos  it  is  much  shorter, 
and  in  the  Sloths  it  is  extremely  short  and  trun- 
cated. The  intermaxillary  bone  is  excessively 
small  in  the  Ant-eaters  and  the  Sloth,  which  are 
not  furnished  with  any  incisive  teeth,  but  in 
Armadillos  it  attains  a  somewhat  greater  degree 
of  development,  especially  in  the  genus  Da- 


EDENTATA. 


49 


Fig.  33. 


Head  of  the  Megatherium. 

sypus.  The  inferior  maxillary  bone  varies 
no  less  in  its  form  in  the  different  genera  of 
this  incongruous  order  than  the  superior.  It 
is  greatly  elongated  and  very  slender  in  the 
Edentata  proper,  particularly  in  the  Ant-eaters ; 
the  ascending  plate  is  thin  and  small,  the  right 
and  left  branches  of  the  bone  are  united  at  the 
symphysis  to  a  considerable  extent,  and  at  a 
very  acute  angle.  In  the  Sloths  this  bone  ex- 
hibits a  very  different  structure;  it  is  short  and 
deep,  the  ascending  plate  is  broad  and  almost 
square,  the  angular  process  is  very  large,  and 
the  two  branches  of  the  jaw  unite  at  the 
symphysis  without  an  angle,  the  anterior  por- 
tion of  each  side  being  curved  inwards  to  meet 
its  fellow.  In  the  Megatherium  the  body  of 
the  bone  is  still  higher  and  shorter,  but  the  an- 
terior part  is  prolonged  into  a  narrow  and  de- 
pressed groove  somewhat  similar  to  that  of  the 
elephant. 

The  vertebral  column. — The  variation  in  the 
form  and  construction  of  the  vertebra  will  be 
found  to  bear  an  exact  relation  to  the  habits  of 
the  different  genera.  The  cervical  vertebra  of 
the  A'i,  Bradypus  triductylus,  have  always,  until 
very  recently,  been  believed  to  form  an  excep- 
tion to  the  general  law,  which  assigns  seven  as 
the  strict  number  of  these  bones  in  the  mam- 
miferous  animals.  That  this  number  should 
exist  equally  in  the  hog  and  the  giraffe  is  in- 
deed a  remarkable  fact,  and  may  be  considered 
as  a  striking  illustration  of  the  law  by  which 
variations  in  volume  in  any  particular  system 
of  organs  are  provided  for  rather  by  the  differ- 
ence in  volume  or  in  the  relative  proportions  of 
the  organs  themselves,  than  by  any  abrupt 
change  in  their  number.  The  supposed  excep- 
tion to  this  law  which  now  comes  under  our 
notice  consists  in  the  fact  that  the  neck  of  the 
animal  in  question,  (speaking  of  the  part 
rather  in  reference  to  its  use  than  in  strict  ana- 
tomical language,)  is  formed  of  nine  vertebrae. 
Two  skeletons  in  my  own  possession,  however, 
have  enabled  me  to  demonstrate  that  the  posterior 
two  of  these  vertebrae  (Jig.  34)  have  attached  to 
them  the  rudiments  of  two  pair  of  ribs  in  the 
form  of  small  elongated  bones  articulated  to  the 
transverse  processes  of  these  bones,  which  are 
therefore  to  be  considered  as  truly  dorsal  ver- 
tebrae, modified  into  a  cervical  form  and  func- 
tion, suited  to  the  peculiar  wants  of  the  animal. 
The  object  of  the  increased  number  of  ver- 
tebrae in  the  neck  is  evidently  to  allow  of  a 
more  extensive  rotation  of  the  head ;  for  as 

VOL.  II. 


Fig.  34. 


Neck  of  the  Sloth. 


each  of  the  bones  turns  to  a  small  extent  upon 
the  succeeding  one,  it  is  clear  that  the  degree 
of  rotation  of  the  extreme  point  will  be  in  pro- 
portion to  the  number  of  moveable  pieces  in 
the  whole  series.  When  the  habits  of  this 
extraordinary  animal  are  considered,  hanging 
as  it  does  from  the  under  surface  of  boughs 
with  the  back  downwards,  it  is  obvious  that  the 
only  means  by  which  it  could  look  downwards 
towards  the  ground  must  be»by  rotation  of  the 
neck  ;  and  as  it  was  necessary,  in  order  to 
effect  this  without  diminishing  the  firmness  of 
the  cervical  portion  of  the  vertebral  column,  to 
add  certain  moveable  points  to  the  number 
possessed  by  the  rest  of  the  class,  the  ad- 
ditional motion  was  acquired  by  modifying 
the  two  superior  dorsal  vertebrae,  and  giving 
them  the  office  of  cervical,  rather  than  in- 
fringing on  a  rule  which  is  thus  preserved 
entire  without  a  single  known  exception. 

In  the  two-toed  Sloth  there  is  but  one  pair  of 
these  rudimentary  ribs,  and  consequently  only 
the  first  dorsal  vertebra  enters  into  the  compo- 
sition of  the  neck. 

The  dorsal  portion  of  the  vertebral  column  is 
particularly  long  in  the  Ant-eaters  as  well  as  the 
Sloth.  These  vertebrae  are  also  generally  more 
numerous  in  this  than  in  most  other  groups— the 
great  Ant-eater  having  sixteen,  the  A'i  fourteen, 
and  the  (Jnau  no  less  than  twenty-three — a  larger 
number  than  is  found  in  any  other  mammi- 
ferous  animal.  The  ribs  offer  some  striking 
peculiarities  in  their  construction.  In  the  Ant- 
eaters  and  Armadillos  they  are  excessively  broad 
with  the  exception  of  the  first  and  second.  In 
the  Myrmecophaga  jubala  and  M.  didacti/la 
they  overlap  each  other  in  an  imbricated  man- 
ner on  the  upper  part, — a  conformation  which 
gives  great  solidity  to  the  chest.  The  Sloths 
and  the  Megatherium  exhibit  also  considerable 
breadth  of  the  ribs,  but  to  a  much  less  extent 
than  that  just  described,  and  the  latter  animal, 


E 


50 


EDENTATA. 


at  least  in  the  remains  lately  described  by  Mr. 
Clift,  the  part  joining  the  sternum,  and  answer- 
ing to  the  cartilages  of  the  ribs,  is  bony  and  is 
connected  to  the  rib  itself  by  a  moveable  arti- 
culation. The  lumbar  vertebra  are  generally 
broad  and  furnished  with  strong  spinous  pro- 
cesses. The  transverse  processes  are  incon- 
siderable in  the  Sloths,  but  large  in  the  Edentata 
proper.  In  the  Armadillos  the  anterior  articu- 
lar processes  are  particularly  strong  and  larger 
even  than  the  spinous.  This  is  the  case,  but  to 
a  less  degree,  in  the  Ant-eaters.  In  the  Orycte- 
ropus  there  are  slight  indications  of  inferior 
spinous  processes  on  most  of  the  lumbar  verte- 
bra, consisting  of  a  small  longitudinal  crest. 
The  caudal  vertebrae  vary  excessively  in  num- 
ber. In  the  Unau  and  Bradypus  didactylus 
they  are  very  few — not  more  than  seven  or 
eight ;  in  the  large  Ant-eater  forty,  and  in  the 
African  Manis  forty-five.  In  the  remains  of 
the  Megatherium  lately  deposited  in  the  Mu- 
seum of  the  Royal  College  of  Surgeons,  the 
tail  would  appear,  according  to  Mr.  Clift's 
computation,  to  consist  of  eighteen  vertebrae  at 
least.  The  caudal  vertebra?  of  the  Edentata 
proper  have  inferior  spinous  processes  of  a 
remarkable  form,  being  constituted  of  two 
branches  meeting  inferiorly  in  the  median  line. 
The  Megatherium  possesses  similar  V-shaped 
processes.  In  the  Myrmecophaga  didactyla  the 
two  branches  are  not  united  in  the  anterior  two 
of  them.  The  sternum  offers  a  considerable 
developement  of  themanubriumor  anterior  bone 
in  the  whole  of  the  Edentata,  particularly  in  the 
Ant-eaters  and  Armadillos.  It  is  also  rather 
large  in  the  Megatherium. 

The  pelvis  in  the  Edentata  proper  is  much 
elongated,  and  the  acetabulum  rather  behind  the 
middle  of  the  whole  length  of  the  bones.  The 
ileum,  which  forms  the  anterior  half  of  the  pel- 
vis in  the  Armadillo,  is  fixed  to  the  sacrum  by 
its  posterior  portion,  a  surface  of  considerable 
extent.  The  ischium  and  pubis  are  large,  the  is- 
chiatic  notch  wide,  and  the  cavity  of  the  pelvis 
capacious.  In  the  Sloths  and  Megatherium 
the  pelvis  is  of  large  dimensions,  the  ilia  very 
broad,  especially  in  the  latter ;  the  cavity  capa- 
cious, and  the  outlet  large.  The  ossa  pubis  are 
joined  at  the  symphysis  in  most  of  the  Eden- 
tata, as  is  now  ascertained  by  Mr.  Clift,  in  the 
Megatherium .  In  the  Myrmecophaga  didac- 
tyla, it  is  stated  by  Cuvier  to  be  open.  The  size 
of  the  pelvis  in  the  Megatherium  is  enormous. 
On  comparison  of  it  with  the  pelvis  of  an 
elephant  eleven  feet  in  length,  Mr.  Clift  found 
that  in  the  former  the  ilia  are  5ft.  lin  ,  and  in 
the  latter  only  3ft.  8in. 

The  anterior  extremity. — The  principal  cha- 
racteristic of  the  bones  of  the  arm  in  the  Sloth 
is  their  extraordinary  length.  The  humerus  is 
very  much  elongated  and  cylindrical,  with  the 
elevations  but  slightly  marked.  The  ulna  and 
radius  axe  ajso  very  long,  and  bowed,  so  that 
the  bones  are  distant  at  the  middle  of  their 
length  ;  the  radius  is  very  broad  anteriorly. 
The  very  complete  power  of  pronation  and  su- 
pination enjoyed  by  this  animal  is  no  less  ob- 
viously suited  to  its  habits  than  the  great 
length  of  its  anterior  extremities  ;  both  of  which 
peculiarities  are  admirably  subservient  to  the 


complicated  objects  of  holding  by  the  boughs, 
of  advancing  along  their  under-surface,  and  of 
reaching  and  bringing  to  the  mouth  the  leaves 
on  which  it  feeds  ;  and  the  structure  of  the 
hand  (Jig.  35)  is  no  less  suited  to  the  same  pur- 


Pig.  35. 


Hand  of  the  Sloth. 


poses.  The  carpus  is  as  long  as  it  is  broad ;  it  is 
composed  of  six  pieces  only,  of  which  four  form 
the  first  series,  and  two  the  second.  The  os 
scaphoides  is  the  largest  of  the  whole,  and  is 
articulated  with  the  os  semilunare  by  a  convex 
articular  surface  :  the  os  cuneiforme  presents  on 
its  ulnar  side  an  oblique  flattened  surface  ;  the 
os  pisiforme,  which  is  not  named  by  Cuvier, 
does  however  exist,  though  it  is  of  small  size. 
The  inner  and  larger  piece  of  the  anterior  series 
probably  consists  of  the  as  trapezium,  trape- 
zoideum,  and  magnum  united;  and  the  external 
one  solely  of  the  os  unciforme.  In  the  Unau  the 
os  trapezoides  is  distinct.  The  metacarpal 
bones,  to  return  to  the  AY,  consist  of  three  per- 
fect and  two  rudimentary,  the  whole  of  which 
are  united  at  their  base  to  each  other  and  to  the 
inner  solid  carpal  piece,  consisting  of  the  three 
bones  before  mentioned;  so  that  in  fact  the  five 
metacarpal  bones,  with  the  os  trapezium,  tra- 
pezoideum,  and  magnum,  form  one  solid  osseous 
piece.  The  fingers,  which  are  three  only,  are 
very  long,  and  consist  each  of  two  moveable 
phalanges  only,  the  first  being  very  small  and 
early  anchylosed  to  the  metacarpal  bone.  In  a 
very  young  skeleton  in  my  possession,  these 
bones  are  not  yet  united.  There  is  but  very 
little  flexion  between  this  part  and  the  second 
phalanx,  but  between  the  latter  and  the  third  or 
ungueal  phalanx  the  flexion  is  complete,  the 
latter  being  bent  down  to  the  palm  with  perfect 
ease.  These  ungueal  bones  are  very  long, 
curved,  laterally  compressed,  large  at  the  base, 
at  which  part  there  is,  as  in  the  cats,  a  bony 
sheath  to  cover  the  base  of  the  claw ;  and  the 
latter  envelopes  the  phalanx  for  about  five-sixths 
of  its  length. 

The  posterior  extremity  in  this  remarkable 
animal  offers  no  less  striking  peculiarities. 
The  breadth  and  openness  of  its  pelvis  have  been 
already  noticed.  Fhefemur  is  articulated  to  the 
acetabulum  so  as  to  stand  obliquely  outwards 
from  the  pelvis  ;  it  has  a  short  head,  and  is  it- 
self rather  short,  strong,  and  flattened.  The 
tibia  and  Jibula  are  long  and  slender,  and  some- 
what curved  ;  the  superior  articular  surfaces  of 
the  tibia  are  flat,  that  of  the  inferior  extremity 


EDENTATA. 


51 


small,  triangular  and  slightly  concave  ;  but  the 
most  extraordinary  articulation  is  that  of  the 
fibula  with  the  astragalus;  its  inferior  extremity 
terminates  in  a  conical  point,  which  enters  and 
plays  in  a  corresponding  cavity  in  the  latter 
bone.  This  peculiarity  of  the  articulation  of 
the  ankle,  which  was  considered  by  Cuvier  as 
only  additional  evidence  of  the  imperfection 
of  the  animal's  structure,  is  no  less  admirably 
adapted  to  its  habits  than  those  points  which 
have  been  previously  noticed.  The  feet,  it  is 
true,  are  turned  inwards,  and  there  is  no  pos- 
sibility of  placing  the  sole  on  the  ground;  but 
it  is  the  better  adapted  for  clasping  boughs, 
and  the  freedom  of  rotation  which  is  provided 
by  this  curious  joint  allows  of  every  kind  of 
motion  required  in  such  circumstances.  The 
tarsus  consists  of  the  astragalus  and  os  calcis, 
which  are  separate,  and  of  the  usual  anterior 
series  of  bones,  which  in  the  aged  individuals 
are  anchylosed  together  as  well  as  to  the  meta- 
tarsal bones,  which  are  themselves  united  as 
in  the  carpus.  The  tubercle  of  the  os  calcis  is 
very  long,  and  so  situated  as  to  afford  a  sort  of 
opposing  thumb  to  the  flexed  phalanges.  The 
latter  bones  very  nearly  resemble  those  of  the 
anterior  extremity. 

It  is  impossible  not  to  be  struck,  even  on  a 
superficial  view  of  the  extraordinary  structure  of 
the  anterior  and  posterior  extremities  of  the  Sloth, 
with  the  complete  adaptation  of  this  deviation 
from  the  normal  form  to  its  peculiar  mode  of 
life.  Grasping  the  boughs  of  trees  on  which  it 
both  feeds  and  reposes,  crawling  along  with 
the  back  downwards  and  the  belly  pressed 
against  the  tree,  and  culling,  with  the  long 
arms,  the  leaves  at  the  inaccessible  extre- 
mities of  the  branches,  the  usual  construction 
of  the  members  would  be  absolutely  useless, 
and  an  incumbrance  instead  of  an  assistance. 
But  by  the  great  breadth  of  the  pelvis,  the  di- 
rection of  the  femora,  the  long  and  curved  claws, 
the  consolidation  of  the  tarsus,  and  the  curious 
structure  of  the  articulation  of  the  fibula  with 
the  astragalus,  every  requirement  of  security 
and  progression  is  obtained;  whilst  in  the  an- 
terior extremity  the  extensive  motion  of  the 
shoulder-joint,  the  great  length  of  the  arms,  the 
complete  flexion  of  the  fingers,  and  other  peculia- 
rities, combine,  with  that  security  and  facility  of 
progression,  the  most  effective  means  of  ob- 
taining the  animal's  peculiar  food. 

Of  the  Edentata  proper. — The  extremities 
in  animals  of  this  class  are,  as  may  be  con- 
cluded from  their  habits,  very 
differently  constituted  from  those 
which  have  just  been  described. 
In  all  of  them  the  object  to  be 
obtained  is  facility  in  digging 
the  ground,  or  scratching  up 
immense  nests,  in  search  of 
the  insects  which  constitute 
the  principal  food  of  most  of 
these  animals.  The  gigantic 
Megatherium,  however,  appears 
to  have  combined  the  phytopha- 
gous character  of  the  Sloth  with 
the  fossorial  habits  of  the  Dasy- 
pus,  and  is  supposed  to  have 
lived    upon    roots,   which  it 


snatched  or  dug  up  with  its  enormous  claws. 
The  scapula  of  theA.nt-eaters  and  Armadillos  is 
found  nearly  like  that  of  the  Sloth  ;  in  the 
Myrmecophagajubata  a  process  of  bone  extends 
from  the  coracoid  process  to  the  anterior  margin, 
rendering  that  which  is  a  notch  in  other  species 
a  complete  foramen.  A  second  spine  inferior 
to  the  true  one  is  also  observed  in  that  species, 
in  which  respect  it  resembles  the  Unau  or 
two-toed  Sloth.  The  scapula  of  the  Armadillos 
is  very  high  and  narrow.  In  that  of  the  Mega- 
therium there  exists  a  large  process  of  bone  ex- 
tending from  the  coracoid  process  to  the  acro- 
mion,andthus  completely  uniting  theseprocesses. 
The  clavicle  exists  in  many  of  the  Edentata,  as 
the  Armadillos  and  Ant-eaters,  but  is  wanting 
in  the  Manis  or  Pangolin.  That  of  the  Megathe- 
rium offers  a  remarkable  peculiarity.  It  extends 
from  the  acromion,  not  to  the  sternum  as  in  all 
other  cases,  but  to  the  first  rib.  The  humerus  is 
in  most  of  the  order  very  short  and  robust,  and 
its  elevations  strongly  marked.  In  the  Ant-eaters 
the  part  above  the  inner  condyle  is  extremely 
developed,  to  give  attachment  to  the  powerful 
flexors  of  the  claws  ;  and  the  crests  for  the  in- 
sertion of  the  deltoid  and  great  pectoral  muscles 
are  very  prominent  and  angular, — a  structure 
which  is  also  conspicuous  in  the  Armadillos  and 
Manis.  The  humerus  of  the  Megatherium  has 
a  similar  general  form;  it  is  rude,  short,  and 
excessively  strong,  with  abrupt  and  large  ele- 
vations for  the  different  muscular  attachments  ; 
the  inferior  part  especially  becomes  suddenly 
larger,  from  the  existence  of  a  strong  and  ele- 
vated external  crest. 

The  habits  of  the  Edentata  proper  demand 
a  very  different  construction  of  the  fore-arm 
from  that  of  the  Sloth.  Requiring  immense 
strength  in  digging  the  ground,  the  short  ole- 
cranon which  exists  in  the  Sloth  would  be 
wholly  inefficient.  A  long  lever  is  necessary, 
and  hence  we  find  that  in  the  whole  of  these 
the  olecranon  is  of  an  extraordinary  length,  and 
that  in  the  Megatherium  its  more  moderate 
length  is  compensated  for  by  its  immense 
strength.  In  the  five-toed  Armadillo  this  pro- 
cess is  so  extensive  as  to  render  the  ulna  no 
less  than  twice  the  length  of  the  radius,  and 
in  the  other  species  of  the  same  genus  it  is 
not  much  less.  Trie  radius  is  broad,  robust, 
and  strongly  marked,  particularly  towards  the 
carpal  extremity.  The  hand  in  the  Myrmeco- 
phuga  (fig  36)  and  its  kindred  genus  Manis 

Fig.  36. 


Hand  of  the  Ant-eater. 


E  2 


S3 


EDENTATA. 


offers  a  very  remarkable  structure.  The  ungueal 
phalanges,  like  those  of  the  Sloth,  are  restricted 
in  their  motion  to  simple  flexion,  in  which 
position  they  are  retained  during  repose  by 
Strong  ligaments.  In  the  Myrmecophaga  the 
terminal  phalanges  are  deeply  grooved  in  the 
margin  ;  in  the  latter  they  are  bifid.  The  pha- 
langes of  the  fingers  themselves  are  very  une- 
qual in  length  and  thickness.  The  middle 
finger  is  of  extraordinary  size,  every  articula- 
tion being  very  robust,  and  almost  twice  as 
thick  as  either  of  the  others;  the  next  on  each 
side  are  nearly  as  long  but  much  smaller,  and 
the  outer  shorter  still  and  very  slender.  The 
outer  finger  has  no  claw  ;  the  four  others  are 
furnished  with  claws.  The  hand  in  Dasypus 
and  Orycleropus  is  also  of  a  very  remarkable 
conformation,  particularly  in  the  gigantic  spe- 
cies of  Armadillo,  Priodunta  gigantea  (Jig  37) 

Fig.  37. 


Hand  of  the  Gigantic  Armadillo. 

of  Fr.  Cuvier.  Amongst  the  peculiarities  of 
structure  in  this  animal  are  the  following. 
In  addition  to  several  remarkable  anomalies 
in  the  carpal  bones,  the  bone  which  results 
from  the  ossification  of  the  flexor  profundus 
muscle  is  very  large,  developed  posteriorly 
into  a  large  and  irregularly  formed  head, 
articulated  by  large  surfaces  to  the  os  semi- 
lunar and  pisiforme,  presenting  concave  sur- 
faces on  the  side  of  the  fore-arm,  and  termi- 
nating towards  the  hand  by  an  enlargement 
which  is  compressed  and  smaller  than  the  head. 
The  metacarpals  are  no  less  extraordinary. 
Those  of  the  thumb  and  index,  as  well  as  their 
phalanges,  are  slender,  of  the  usual  construc- 
tion, but  that  of  the  middle  finger  is  irregularly 
rectangular  and  broader  than  it  is  long ;  and  the 
phalanx  which  it  supports  is  of  a  corresponding 
form  and  size,  being  extraordinarily  short  and 
broad.  The  corresponding  bones  of  the  fourth 
finger  are  similarly  formed,  but  somewhat 
smaller.  The  ungueal  or  terminal  phalanx  of 
the  middle  finger  is  enormously  large  and 
strong,  curved  outwards,  and  having  at  its  base 
a  large  bony  hood  or  case  for  the  lodgement  of 
the  claw;  the  terminal  phalanx  of  the  fourth 
finger  is  similar,  but  of  somewhat  smaller  di- 
mensions. The  fifth  or  little  finger  is  much 
smaller,  but  is  furnished  with  a  claw  of  some 
size.  The  conformation  of  the  hand  of  this 
animal  affords  a  most  formidable  weapon,  or 
as  a  powerful  fossorial  instrument,  in  the  three 
outer  claws,  whilst  the  two  inner  ones  are  only 
formed  for  scratching  or  other  similarly  slight 
actions. 

The  posterior  extremity  of  the  Edentata 
proper  offers  perhaps  less  striking  peculiarities 
of  structure.    The  femur  in  general  is  of  mo- 


derate length,  but  large  and  strong;  and  an 
elevated  crest,  arising  from  the  great  trochanter, 
extends  nearly  the  whole  length  of  the  bone. 
In  the  Ant-eaters  and  the  Megatherium,  it  is 
particularly  broad  and  flattened,  and  the  greater 
and  lesser  trochanters  are  not  particularly  pro- 
minent. In  the  genus  Dasypus  the  great  tro- 
chanter on  the  contrary  is  of  great  size,  and 
from  the  middle  of  its  outer  margin  arises  a 
large  process  which  is  directed  outwards.  The 
tibia  and  fibula  in  the  latter  genus  are  extremely 
broad,  arched,  and  anchylosed  at  both  extremi- 
ties. In  the  Ant-eaters,  on  the  other  hand,  these 
bones  are  of  the  ordinary  form,  and  have  no 
osseous  union.  In  the  Megatherium  they  are 
united  by  the  superior  third  of  their  length,  and 
closely  in  contact  at  the  lower  part ;  they  are 
both  short  and  extremely  thick,  particularly  the 
tibia.  The  tarsus  is  composed  in  the  two-toed 
Ant-eaters  of  at  least  eight  distinct  bones,  the 

largest  of  which  is  a  supernumerary 
'  bone,  situated  at  the  inner  part  of  the 

5335^s  foot,  upon  the  scaphoid;  it  extendsback- 

wards  as  far  as  the  tuberosity  of  the 

os  calcis,  and  thus  forms  a  broad  base 
Ik        to  the  posterior  part  of  the  sole  of  the 
\  11       foot.    The  Myrmecophaga  jubata  has 
\  1       also  a  supernumerary  bone,  but  of 
t/       smaller  dimensions ;  but  the  Armadillos 

and  Orycteropus  have  but  the  seven  or- 
dinary bones  of  the  tarsus.  The  metatarsal 
bones  and  the  toes  are  probably  invariably  five 
throughout  the  Edentata  proper;  the  toes  of 
the  posterior  extremity  offer  few  peculiarities  of 
any  consequence.  Both  the  anterior  and  poste- 
rior feet  of  the  Megatherium  are  peculiar  in  their 
structure.  In  the  former,  those  fingers  which 
are  completely  formed  are  the  three  middle 
ones,  the  little  finger  being  rudimentary,  and 
the  thumb  having  no  claw.  The  ungueal  pha- 
langes of  the  three  former  are  enormously  deve- 
loped, principally  as  regards  the  bony  enve- 
lope for  the  base  of  the  claw ;  the  size  and 
thickness  of  which  indicate  that  the  claws 
themselves  must  have  been  of  great  size  and 
immense  strength,  and  have  afforded  powerful 
implements  for  tearing  up  the  suiface  of  the 
ground  in  search  of  roots.  On  the  hinder 
foot,  there  is  a  single  toe  of  a  similar  con- 
struction, which  is  the  third  ;  the  fourth  and 
fifth,  although  of  considerable  size,  bore  no 
claws.  This  enormous  extinct  animal  is  cer- 
tainly among  the  most  extraordinary  produc- 
tions of  the  ancient  world.  Of  dimensions  the 
most  unwieldy,  and  with  a  skeleton  as  solid  as 
that  of  the  most  enormous  amongst  the  Pachy- 
dermata,  we  find  a  cranium,  and  especially 
teeth,  which  exhibit  a  very  near  relation  to  those 
of  the  Sloth,  and  members  which  are  no  less 
remarkably  allied  to  the  Ant-eaters  and  the  Ar- 
madillos. However  the  difference  in  bulk  may 
iippear  at  first  sight  to  interfere  with  the  idea  of 
these  affinities,  and  however  difficult  it  may  be 
at  once  to  reconcile  the  relation  between  a 
small  active  animal  like  the  Armadillo,  or 
an  inhabitant  of  trees  like  the  Sloth,  and 
this  enormous  and  unwieldy  tenant  of  the 
earth's  earlier  surface,  the  affinities  are  neither 
less  true  nor  more  probable  than  those  which 
subsist  between  the  light  rabbit-like  hyrax 


EDENTATA. 


53 


and  the  ponderous  rhinoceros  of  the  present 
world. 

There  is  still  another  very  interesting  animal, 
the  account  of  whose  osteology  I  have  not  in- 
termixed with  that  of  the  other  Edentata,  be- 
cause it  is  as  yet  but  little  known,  and  because 
its  peculiarities  are  particularly  interesting. 
This  is  the  Chlamyphorus  truncatus  (fig-  38)  of 
Dr.Harlam,  of  which  I  have  the  opportunity  of 


animals  belonging  to  the  same  order.  To  the 
Echidna  and  Ornithorynchus  it  is  also  similar 
in  the  first  bone  of  the  sternum,  and  in  the 
bony  articulations  as  well  as  the  dilated  con- 
necting plates  of  the  true  and  false  ribs. 

"  In  the  form  of  the  lower  jaw,  and  in  other 
points  equally  obvious,  the  Chlamyphorus  ex- 
hibits characters  to  be  found  in  some  species 
of    Ruminant  ia    and    Pachydermuta.  On 


Skeleton  of  the  CMamyplwrus  truncatus. 


offering  a  very  correct  figure,  for  which  I  am 
indebted  to  the  kindness  of  my  friend  Mr. 
Yarrell.  This  very  remarkable  animal  was 
discovered  in  the  interior  of  Chili,  burrowing 
like  the  mole,  and  like  that  animal  residing 
principally  underground.  The  detail  of  its 
organization  will  be  found,  as  given  by  Mr. 
Yarrell,  in  the  third  volume  of  the  Zoolo- 
gical Journal,  to  which  I  refer.  The  general 
results  of  that  gentleman's  observations  are  as 
follow  : 

"  It  has  much  less  real  resemblance  to  the 
mole,  Talpa  Europea,  than  its  external  form 
and  subterranean  habits  would  induce  us  to 
expect.  In  the  shortness  and  great  strength  of 
the  legs,  and  in  the  articulation  of  the  claws  to 
the  first  phalanges  of  the  toes,  it  is  similar ;  but 
in  the  form  of  the  bones  of  the  anterior  extre- 
mity, as  well  as  in  the  compressed  claws,  it  is 
perfectly  different ;  nor  do  the  articulations  of 
the  bones  nor  the  arrangement  of  the  muscles, 
allow  any  of  the  lateral  motion  so  conspicuous 
in  the  mole.  The  hinder  extremities  of  the 
Chlamyphorus  are  also  much  more  powerful. 

"It  resembles  the  Brady  pus  tridactylus  in  the 
form  of  the  teeth,  and  in  the  acute  descending 
process  of  the  zygoma,  but  here  all  comparison 
with  the  Sloth  ceases. 

"  The  skeleton  of  the  Chlamyphorus  will  be 
found  to  resemble  that  of  the  Armadillo  (Dasypi 
species  plures)  more  than  any  other  known 
quadruped.  In  the  peculiar  ossification  of  the 
cervical  vertebrae ;  in  possessing  the  sesamoid 
bones  of  the  feet ;  in  the  general  form  of  all 
the  bones,  except  those  of  the  pelvis,  as  well  as 
in  the  nature  of  the  external  covering,  they  are 
decidedly  similar ;  they  differ  however  in  the 
form  and  appendages  of  the  head,  in  the  com- 
position and  arrangement  of  the  coat  of  mail, 
and  particularly  in  the  posterior  truncated  ex- 
tremity and  tail. 

"  There  is  a  resemblance  to  be  perceived  in 
the  form  of  some  of  the  bones  of  the  Chlamy- 
phorus to  those  of  the  Oryctcropus  capensis  and 
Murmecophaga  jubata,  as  might  be  expected  in 


this  sketch  of  its  relations  it  is  unnecessary 
to  dilate.  Its  near  affinity  to  the  genera  Dasy- 
pus  and  Tatusia  however  is  so  obvious  that 
there  can  be  no  doubt  of  the  propriety  of  con- 
sidering it  as  belonging  to  the  same  family  of 
the  order;  whilst  its  relation  to  the  mole  can 
of  course  only  be  considered  as  one  of  analogy, 
in  which  respect  it  offers  many  interesting 
characters." 

Digestive  organs. — In  the  character  of  these 
organs  there  is  no  less  diversity  between  the 
Turdigrada  and  the  Edentata  proper  than  in 
the  osteology  already  described.  The  former, 
essentially  herbivorous,  yet  living  principally 
upon  the  young  succulent  leaves  which  clothe 
the  extremities  of  the  branches,  have  the  teeth 
formed  for  bruising  this  kind  of  nourishment, 
and  an  articulation  of  the  lower  jaw  which 
allows  of  a  degree  of  motion  commensurate 
with  the  object.  The  teeth  consist  of  a  cylinder 
of  bone  enclosed  within  a  simple  case  of 
enamel,  but  without  any  of  the  convolutions 
of  these  two  substances  which  characterize  the 
structure  of  these  organs  in  the  Ruminantia 
and  other  graminivorous  animals.  They  are 
in  fact  the  most  simple  which  are  found  in 
any  of  the  Mammifera.  There  is  a  single 
canine  on  each  side  above  and  below,  both 
in  the  Unau,  but  none  in  the  Ai. 

In  one  form  of  the  Armadillos,  the  genus 
Dasypus  as  now  restricted,  there  are  two  in- 
cisive teeth  in  the  upper  and  four  in  the  lower 
jaw,  and  sixteen  molares  in  each.  In  the 
allied  genus  Tatusia  there  are  no  incisive  or 
canine  teeth,  and  the  molares  are  even  rather 
more  numerous,  and  in  the  Priodonta  Gigas 
there  are  no  less  than  fifty  in  the  upper  and 
forty-eight  in  the  lower  jaw.  These  are  all 
simple,  and  formed  for  crushing  insects. 

The  stomach  in  the  Sloths  is  very  remarkably 
formed.  In  the  Brady  pus  didactylus  (Jig.  39)  it 
is  double.  The  first  is  large  and  rounded,  con- 
tracted posteriorly,  and  produced  into  a  conical 
appendix,  which  is  doubled  from  the  left  to 
the  right,  and  its  cavity  is  separated  from  that 


54 


EDENTATA. 


Fig.  39. 


Stomach  of  the  Sloth. 


of  the  stomach  by  a  semilunar  fold.  The 
cardia  opens  very  far  towards  the  right  side, 
leaving  a  very  large  pouch,  and  enters  a  canal 
which  proceeds  along  the  right  side  of  the 
first  stomach,  giving  off  from  its  right  margin 
a  broad  process,  which  separates  the  pouch 
of  the  stomach  from  the  other  cavity,  which 
lies  between  the  pouch  and  the  appendix 
before  mentioned.  Thus  the  first  stomach 
is  divided  into  three  cavities.  The  canal 
already  described  turns  from  the  left  towards 
the  right,  and  enters  the  second  stomach  by 
a  narrow  opening.  The  second  stomach  is 
of  a  slender  form,  much  smaller  than  the 
former ;  its  parietes  are  very  thin  for  the  first 
half  of  its  length,  but  much  thickened  towards 
the  pylorus ;  and  the  two  portions  are  sepa- 
rated by  a  semilunar  fold.  Again,  the  first 
portion  of  this  second  stomach  is  itself  partially 
divided  by  a  beautifully  indented  fold,  the 
dentated  processes  of  which  are  directed 
towards  the  pylorus.  There  is  also  attached 
to  the  second  stomach  a  small  cul-de-sac, 
which  lies  between  two  similar  ones  connected 
with  the  first  stomach,  the  internal  surface  of 
all  of  which  appears  to  be  glandular.  In  the 
AT  the  appendix  to  the  second  stomach  is  much 
longer,  and  divided  into  three  chambers  by 
two  membranous  partitions. 

The  whole  of  this  structure,  and  especially 
the  canal  which  extends  from  the  cardia  to  the 
second  stomach,  indicates  a  very  remarkable 
relation  to  that  of  the  ruminants,  and  is 
evidently  intended  for  the  digestion  of  vege- 
table substances  only. 

In  the  Edetitata  proper  the  stomach  is,  as 
may  be  expected,  far  more  simple.  In  the 
Myrmecophaga  didactyla  it  is  of  a  globular 
form,  and  simple.  In  the  Manis  pentadaclyla 
or  Pangolin,  it  is  internally  divided  by  a  fold 
into  two  cavities,  of  which  the  left,  analogous 
to  the  paunch,  is  thin,  and  the  pyloric,  or  true 
digestive  portion,  much  thicker. 

The  intestinal  canal  does  not  present  the 
same  striking  distinctions  between  the  large 
and  small  intestines  which  are  observed  in 
most  other  mammifera.  There  are  in  the 
Ant-eaters  two  ccecal  appendices,  which  may 
be  considered  as  forming  the  boundary  between 
the  two  portions,  of  which  the  posterior  is 
very  much  shorter  than  the  anterior.  It  is 
remarkable  that  the  entrance  to  these'  small 
cceca  is  so  contracted  as  wholly  to  prevent 


the  passage  of  any  faeces  into  them.  In  the 
Munis  longicauda  there  is  not  the  vestige  of  a 
coecum.  In  the  Orycteropus  it  is  short  and 
oval.  In  the  Turdigrada,  the  Ai  for  example, 
the  large  intestine  is  at  once  distinguished 
from  the  small  by  its  sudden  enlargement,  and 
at  their  junction  is  found  a  slight  fold,  which 
partially  separates  them. 

The  liver  offers  but  few  peculiarities  of 
consequence  in  a  physiological  point  of  view. 
In  the  Ant-eaters,  the  Armadillos,  and  the 
Orycterope,  it  consists  of  three  lobes.  In 
the  former  the  hepatic  duct  joins  the  cystic 
at  a  considerable  distance  from  the  neck  of 
the  gall-bladder,  and,  as  in  the  Armadillo,  at 
a  very  acute  angle. 

Organs  of  circulation. — In  a  paper  in  the 
Philosophical  Transactions,  Sir  A.  Carlisle 
described  a  very  remarkable  peculiarity  of  the 
arrangement  of  the  arteries  of  the  limbs  in 
several  slow-moving  animals,  of  which  number 
were  the  Bradypus  tridactylus  and  Bradypus 
didactylus.  It  appears  that  the  axillary  and 
iliac  arteries,  on  entering  the  upper  and  lower 
limbs,  are  suddenly  divided  into  a  number  of 
cylinders  of  equal  size,  which  occasionally 
anastomose  with  each  other.  They  are  ex-  * 
clusively  distributed  in  the  muscles.  Those 
of  the  other  parts  of  the  body,  and  even 
those  of  the  limbs  which  supply  the  bones, 
&c.  do  not  deviate  from  the  usual  mode  of 
distribution.  In  the  former  species  no  less 
than  forty-two  of  these  cylinders  were  counted 
on  the  superficies  of  the  brachial  fasciculus, 
and  there  were  probably  not  less  than  twenty 
concealed  in  the  middle.  In  the  second 
species  they  were  less  numerous,  and  deviated 
from  the  usual  form.  This  difference  in  the 
two  species  is  perfectly  consistent  with  what 
is  known  of  their  habits  ;  for  there  can  be  no 
doubt  that  the  peculiarity  has  reference  to  the 
slowness  of  motion  of  these  animals,  in  which 
character  the  Ai  far  exceeds  the  Unau.  "  The 
effect  of  this  peculiar  disposition  of  the  arteries, 
in  the  limbs  of  these  slow-moving  quadrupeds, 
will  be  that  of  retarding  the  velocity  of  the 
blood.  It  is  well  known,  and  has  been 
explained  by  various  writers,  that  the  blood 
moves  quicker  in  the  arteries  near  the  heart 
than  in  the  remote  branches ;  and  also,  that 
fluids  move  more  rapidly  through  tubes  which 
branch  oft*  suddenly  from  large  trunks  than 
if  they  had  been  propelled  for  a  considerable 
distance  through  small-sized  cylinders ;  be- 
sides the  frequent  communications  in  the 
cylinders  of  the  Bradypus  tridactylus  must 
produce  eddies  which  will  retard  the  progress 
of  the  fluid.  From  these  and  a  variety  of 
other  facts,  it  will  appear  that  one  effect  on 
the  animal  economy,  connected  with  this  ar- 
rangement of  vessels,  must  be  that  of  di- 
minishing the  velocity  of  blood  passing  into 
the  muscles  of  the  limbs.  It  may  be  difficult 
to  determine  whether  the  slow  movement  of 
the  blood  sent  to  these  muscles  be  a  subor- 
dinate convenience  to  other  primary  causes  of 
their  slow  contraction,  or  whether  it  be  of 
itself  the  immediate  and  principal  cause." 
The  integument  in  the  Manis  as  well  as  in 


ELASTICITY 


55 


the  genera  Dasi/pus  and  Tutmia,  comprehend- 
ing the  Armadillos,  and  in  Chlumyplwrus,  ex- 
hibits various  modifications  of  a  very  extraordi- 
nary nature.  The  body  of  the  Munis  is  co- 
vered with  large  imbricated  scales,  of  a  more 
or  less  rhomboidal  form,  of  a  horny  consistence, 
and  a  reddish  brown  colour.  The  true  struc- 
ture of  these  scales  is  undoubtedly  a  congeries 
of  hairs,  as  is  evinced  in  the  longitudinal 
lines  with  which  they  are  all  marked.  They  form 
a  very  firm  and  complete  protection  to  the 
animal  when  rolled  up  in  a  ball,  which  is  its 
ordinary  means  of  escaping  from  danger.  The 
scales  cover  the  whole  surface,  excepting  the 
inferior  part  of  the  head  and  tail,  the  axilla;, 
the  middle  of  the  belly,  the  inner  surface  of  the 
thighs,  and  the  soles  of  the  feet,  all  of  which 
parts,  excepting  the  latter,  are  furnished  with  a 
few  scattered  hairs.  In  the  Armadillos  an 
osseous  crust  or  shell  envelopes  the  whole  of 
the  upper  part  of  the  head  and  the  body,  the 
outer  part  of  the  limbs,  and  the  whole  of  the 
tail.  The  inferior  parts  of  the  body  are  not 
thus  protected,  but  scantly  covered  with  hair, 
intermixed  with  a  kind  of  hard  warts  or  scales. 
Their  armour  is  composed  of  a  helmet  covering 
the  upper  part  of  the  head,  of  a  buckler  over 
the  shoulders,  a  similar  one  over  the  crupper, 
and  the  back  has  numerous  imbricated  bands, 
which  move  upon  each  other,  varying  in  num- 
ber in  the  different  species;  the  tail  is  covered 
by  rings,  also  allowing  of  motion.  It  is  clear 
that  this  hard  bony  armour  is  capable  of  afford- 
ing these  animals  the  most  complete  protection 
when  coiled  up,  which  is  the  position  usually 
assumed  by  them  when  in  danger,  or  during 
repose.  Although  there  is  mutual  motion  only 
at  the  margins  of  the  different  pieces  and  at  the 
commissures  of  the  bands,  there  is  considerable 
yielding  at  every  portion  of  this  coat  of  mail. 
Each  of  the  larger  pieces  is  composed  of  nume- 
rous adherent  smaller  ones,  hexagonal,  and  per- 
fectly tessellated ;  those  of  the  shoulders  are 
arranged  in  segments  of  concentric  circles,  the 
concavity  being  in  front,  so  that  the  anterior 
series,  which  is  the  shortest,  embraces  the  neck 
of  the  animal.  The  covering  of  the  posterior 
part  has  a  similar  arrangement,  but  reversed, 
so  that  the  short  concave  margin  meets  the 
origin  of  the  tail.  The  cuirass  of  the  Chlamy- 
plwrus  truncatus  differs  in  many  respects  from 
that  of  the  Armadillos,  and  is  thus  described 
by  Dr.  Harlam  in  the  only  account  which  we 
have  of  the  details  of  this  singular  animal,  with 
the  exception  of  the  very  interesting  descrip- 
tion of  its  osteology  by  Mr.Yarrell,  in  the  third 
volume  of  the  Zoological  Journal. 

"  The  shell  which  covers  the  body  is  of  a 
consistence  somewhat  more  dense  and  inflexi- 
ble than  sole  leather  of  equal  thickness.  It  is 
composed  of  a  series  of  plates  of  a  square, 
rhomboidal,  or  cubical  form  ;  each  row  sepa- 
rated by  an  epidermal  or  membranous  produc- 
tion, which  is  reflected  above  and  beneath,  over 
the  plates  ;  the  rows  include  from  fifteen  to 
twenty-two  plates;  the  shell  being  broadest  at 
its  posterior  half,  extending  about  one-half 
round  the  body ;  this  covering  is  loose  through- 


out, excepting  along  the  spine  of  the  back  and 
top  of  the  head  ;  being  attached  to  the  back 
immediately  above  the  spine,  by  a  loose  arti- 
cular production,  and  by  two  remarkable  bony 
processes ;  on  the  top  of  the  os  fronds,  by 
means  of  two  large  plates,  which  are  nearly  in- 
corporated with  the  bone  beneath  ;  but  for  this 
attachment,  and  the  tail  being  firmly  curved 
beneath  the  belly,  the  covering  would  be  very 
easily  detached.  The  number  of  rows  of  plates 
on  the  back,  counting  from  the  vertex,  (where 
they  commence,)  is  twenty-four;  at  the  twenty- 
fourth  the  shell  curves  suddenly  downwards, 
so  as  to  form  a  right  angle  with  the  body  ;  this 
truncated  surface  is  composed  of  plates  nearly 
similar  to  those  of  the  back  ;  they  are  disposed 
in  semicircular  rows,  five  in  number  ;  the  lower 
margin  somewhat  elliptical,  presents  a  notch  in 
its  centre,  in  which  is  attached  the  free  portion 
of  tail,  which  makes  an  abrupt  curvature,  and 
runs  beneath  the  belly  parallel  to  the  axis  of 
the  body  ;  the  free  portion  of  the  tail  consists 
of  fourteen  caudal  vertebra1,  surrounded  by  as 
many  plates,  similar  to  those  of  the  body  ;  the 
extremity  of  the  tail  being  depressed  so  as  to 
form  a  paddle  ;  the  rest  of  the  tail  compressed. 
The  caudal  vertebra?  extend  up  to  the  top  of 
the  back,  beneath  the  truncated  surface,  where 
the  sacrum  is  bent  to  meet  the  tail.  The  supe- 
rior semicircular  margin  of  the  truncated  sur- 
face, together  with  the  lateral  margins  of  the 
shell,  are  beautifully  fringed  with  silky  hair.'' 

It  is  much  to  be  regretted  that  but  little  is 
known  of  the  generation  of  these  animals.  The 
dissections  which  have  hitherto  been  made  of 
the  more  interesting  forms  have  been  imper- 
fectly performed,  or  the  subjects  themselves 
have  been  in  such  a  condition  as  to  allow  of 
but  very  incomplete  observations. 

For  BiBUo^A'rHiY,  see  that  of  Mammalia. 

ELASTICITY  (Germ.  Springkraft,  Fe- 
derkrqf't)  is  that  property  of  natural  bodies  in 
virtue  of  which  they  admit  of  change  either  of 
size  or  form  from  the  application  of  external 
force,  resuming,  upon  the  suspension  of  that 
force,  their  proper  shape  or  volume. 

Though  elasticity  is  a  purely  physical  pro- 
perty, its  investigation  is  scarcely  less  interest- 
ing in  physiological  than  in  mechanical  science. 
The  most  cursory  examination  of  a  living  body 
is  sufficient  to  convince  us,  that  nature,  in 
regulating  its  varied  functions,  has  availed 
herself  no  less  of  physical  than  of  vital  laws. 
As  it  is  the  province  of  the  physiologist  to 
explain  and  analyze  the  several  actions  whose 
aggregate  is  life,  to  trace  each  to  its  proper 
source,  and  to  distinguish  those  which  are 
truly  vital  from  those  which  are  merely  mecha- 
nical, it  is  plain  that  an  acquaintance  with  the 
physical  properties  of  the  material  elements  of 
living  bodies  becomes  one  of  the  foundations 
of  his  knowledge.  Hence,  in  a  publication, 
the  design  of  which  is  to  present  a  complete 
view  of  the  structure  and  functions  of  living 


5(3 


ELASTICITY. 


beings,  it  would  be  improper  to  omit  some 
notice  of  those  properties  of'  matter  which  are 
so  frequently  and  so  admirably  employed  in 
fitting  them  for  their  uses.  In  this  article  we 
shall  offer,  in  the  first  place,  some  remarks 
upon  elasticity  generally,  upon  its  laws,  and 
upon  the  distinction  between  it  and  other 
forces  ;  we  shall  next  advert  to  its  existence  in 
the  organized  tissues  of  the  animal  machine ; 
and,  lastly,  we  shall  point  out  some  important 
actions  in  the  living  body  where  elasticity  plays 
a  principal  part. 

I.  General  remarks  on  elasticity — its  laws, 
fyc. — The  degree  of  elasticity  possessed  by  un- 
organized bodies  is  extremely  variable;  in 
some  it  is  so  great  that  they  have  obtained  the 
name  of  perfectly  elastic ;  while  in  others  this 
property  is  so  extremely  small,  that  its  very 
existence  has  been  overlooked.  Air  is  the 
most  perfectly  elastic  substance  with  which 
we  are  acquainted  ;  in  experiments  made  upon 
atmospheric  air  a  portion  of  it  has  been  left 
for  years  subjected  to  a  continued  pressure, 
upon  the  removal  of  which  under  the  same 
temperature  and  barometric  altitude,  it  forth- 
with resumed  its  original  volume.  Amongst 
solid  bodies,  the  most  conspicuously  elastic 
are  certain  metals  and  metallic  alloys,  glass, 
ivory,  &c;  while  other  solids,  such  as  moist 
clay,  butter,  wax,  and  many  similar  substances, 
possess  elasticity  in  an  almost  imperceptible 
degree.  Fluids  have  long  been  considered  as 
completely  inelastic ;  but  though  it  is  ex- 
tremely difficult  to  demonstrate  this  property, 
yet  the  experiments  of  Canton  would  seem  to 
indicate  its  existence ;  they  place  at  least  be- 
yond all  doubt  their  possession  of  another 
property,  namely,  compressibility,  —  a  pro- 
perty somewhat  allied  to  that  we  are  now  con- 
sidering. 

The  laws  which  regulate  the  elastic  force 
are  not  exactly  the  same  in  these  three  classes 
of  natural  bodies.  In  the  gaseous  or  perfectly 
elastic  bodies  elasticity  may  be  said  to  deter- 
mine their  volume :  their  particles  having  an 
incessant  tendency  to  expand  into  a  greater 
space  are  controuled  merely  by  the  surround- 
ing pressure,  and  hence  the  bulk  of  gases  is 
always  inversely  proportional  to  the  compres- 
sing force.  This  law,  at  least  in  the  case  of 
atmospheric  air,  applies  within  all  known  de- 
grees of  condensation  and  rarefaction.  By 
means  of  accumulated  pressure,  air  may  be  so 
reduced  in  volume,  that  upon  suddenly  libe- 
rating it,  as  in  the  air-gun,  it  expands  with 
amazing  force  ;  and  in  the  receiver  of  the  air- 
pump,  even  when  reduced  to  one-thousandth 
pirt  its  original  quantity,  it  has  still  elasticity 
enough  to  raise  the  valve.  Another  important 
law  of  elasticity  in  gases  is  that  its  power  is 
increased  by  heat  and  diminished  by  cold, 
and  this  applies  not  only  to  the  permanently 
elastic  gases  but  to  those  likewise  of  another 
kind,  such  as  the  vapours  of  alcohol,  mer- 
cury, nitric  and  muriatic  acids,  and  water ;  the 
elastic  vapours  of  the  nitric  and  muriatic  acids 
not  unfrequently  burst  the  vessels  containing 
them ;  the  vapours  of  mercury  have  broken 


through  an  iron  box ;  and  the  vapours  of  al- 
cohol have  sometimes  occasioned  in  distil- 
leries the  most  terrible  explosions :  the  elas- 
ticity of  steam,  and  the  fact  that  wg  can  in- 
crease its  power  to  any  extent  by  means  of 
heat,  has  enabled  us  to  construct  the  steam- 
engine,  and  thus  armed  mankind  with  a  phy- 
sical power  superior  to  every  obstacle. 

Solid  bodies  are  never  perfectly  elastic ;  for 
although  some,  when  acted  upon  by  forces 
within  a  certain  range,  are  as  completely  elastic 
as  the  gases  themselves,  yet  if  the  disturbing 
force  be  carried  beyond  a  certain  degree,  they 
will  never  resume  their  original  condition. 
Thus,  a  harp-string  gently  drawn  by  the  finger 
is  thrown  by  its  elasticity  into  vibratory  mo- 
tions, returning  when  these  have  ceased  to  its 
exact  original  state:  this  may  be  frequently 
repeated  and  always  with  the  same  effect,  as 
proved  by  the  same  note  being  repeatedly  ob- 
tained. If,  however,  it  be  once  drawn  with  too 
great  a  force,  it  no  longer  returns  to  its  original 
condition,  a  different  tone  is  now  produced  by  it : 
in  other  words,  the  solid  substance  of  which 
it  is  composed  exhibits  a  perfect  elasticity, 
not,  as  the  gases,  under  every  degree  of  force, 
but  only  within  a  certain  limit.  Heat  pro- 
duces very  different  effects  upon  the  elasticity 
of  gaseous  and  solid  bodies;  we  have  just 
seen  that  we  can  increase  the  elastic  power  of 
the  former  to  any  extent  by  means  of  heat, 
but  the  elasticity  of  solids  is,  on  the  contrary, 
usually  diminished  by  it ;  very  high  tempera- 
tures completely  destroy  it  even  in  the  most 
elastic  metals.  The  design  of  this  article  does 
not  permit  us  to  enter  more  fully  into  the  con- 
sideration of  those  laws,  or  of  the  experiments 
by  which  they  are  demonstrated.  We  must 
refer  for  the  further  investigation  of  this  sub- 
ject to  works  which  treat  expressly  upon 
physics. 

The  various  hypotheses  which  have  been 
put  forth  to  explain  the  nature  of  elasticity, 
though  many  of  them  extremely  ingenious, 
do  not  however  properly  come  within  the  pro- 
vince of  the  physical  much  less  of  the  phy- 
siological enquirer.  Indeed,  while  men  di- 
rected their  attention  to  such  speculations  little 
or  no  progress  was  made  in  real  knowledge. 
The  cause  of  elasticity,  like  that  of  life,  is 
probably  beyond  the  sphere  of  human  un- 
derstanding ;  and  hence,  in  both  sciences,  the 
method  of  investigation  should  be  the  same — 
to  study  the  laws  or  conditions  under  which 
the  phenomena  present  themselves,  and  to  lay 
aside  all  speculations  as  to  their  causes.  But 
in  abandoning  these  inquiries  into  the  nature 
of  elasticity  we  must  particularly  advert  to  the 
necessity  of  the  physiologist  possessing  a  clear 
and  definite  idea  of  this  property  of  matter, 
so  as  to  be  enabled  to  recognize  it  under  every 
circumstance,  and  to  distinguish  it  from  other 
physical  and  vital  forces.  Ignorance  upon  this 
point  has  been  at  all  times  a  fruitful  source  of 
error  in  physiological  investigations.  The  pro- 
perty with  which  it  is  especially  liable  to  be 
confounded  is  contractility :  when  it  is  re- 
membered that  at  one  period  of  medic  al  his- 


ELASTICITY. 


S7 


tory  these  two  properties  were  looked  upon  as 
identical ;  that  even  the  illustrious  Cullen  has 
scarcely  distinguished  them,  and  that  some  of 
our  most  eminent  living  physiologists  have 
fallen  into  manifest  errors  upon  the  same  sub- 
ject, it  becomes  plain  that  we  cannot  be  too 
particular  in  familiarizing  ourselves  with  the 
distinctions  between  these  totally  independent 
forces. 

It  is  not  enough  to  say  that  contractility  is 
a  vital  and  elasticity  a  physical  property;  for 
as  we  are  ignorant  alike  of  the  nature  of  life 
and  of  elasticity,  a  distinction  founded  upon 
any  such  assumption  must  necessarily  be  futile. 
It  is  only  by  a  diligent  comparison  of  then- 
respective  laws  that  we  can  assign  to  each  its 
proper  limits.  Let  us  then  observe  in  con- 
trasting them,  first,  that  elasticity  can  never 
act  as  a  prime  mover;  it  is  never  a  source  of 
power,  but  merely  the  reaction  of  a  force  pre- 
viously applied :  thus,  the  elasticity  of  the 
spring  will  never  of  itself  set  the  watch  in 
motion  unless  some  external  force  shall,  in  the 
first  instance,  have  acted  upon  or  bent  it.  But 
contractility  can  of  itself  originate  motion,  at 
least  it  is  not  essential  that  any  mechanical 
force  with  which  we  are  acquainted  should 
precede  its  action.  Again,  the  force  of  elas- 
ticity can  never  exceed  that  other  power  which 
has  called  it  into  existence ;  if,  for  instance, 
a  weight  of  one  pound  be  required  to  depress 
an  elastic  spring,  the  force  of  reaction  upon 
the  removal  of  that  weight  can  never  exceed 
the  measure  of  a  pound.  But,  in  the  case  of 
muscular  contraction,  there  is  no  such  limit ; 
there  is  no  fixed  ratio  between  the  cause  and 
the  effect;  the  slightest  touch  of  a  sharp  in- 
strument will,  in  an  irritable  muscle,  such  as 
the  heart,  excite  the  most  violent  contractions. 
Elasticity  cannot  manifest  itself  except  by  the 
removal  or  suspension  of  the  cause  which  has 
called  it  into  action  :  muscularity  requires  no 
such  suspension  of  its  exciting  cause.  The 
exciting  cause  of  elasticity  is  always  of  a  phy- 
sical nature;  but  many  other  causes  no  ways 
allied  to  physical  ones  may  excite  the  muscular 
power.  Lastly,  elasticity  is  not  destroyed  by 
death  nor  affected  by  opium  or  other  narcotics, 
while  contractility  presents  a  very  striking  con- 
trast in  both  these  respects. 

These  facts  are  quite  conclusive  in  proving 
that  muscular  and  elastic  contraction  are  go- 
verned by  distinct  laws,  and  cannot  conse- 
quently be  referred  to  the  same  source.  But 
if  some  physiologists  have  erred  in  overlooking 
the  distinctions  between  these  two  properties, 
if  they  have  not  analysed  with  sufficient  care, 
others  have  unquestionably  erred  in  an  oppo- 
site direction,  and  by  pushing  analysis  too  far, 
have  attributed  to  imaginary  forces  effects 
which  are  the  result  of  elasticity  alone.  We 
feel  much  diffidence  in  controverting  any  doc- 
trine supported  by  the  genius  and  authority 
of  Bichat,  but  we  confess  that  the  distinction 
which  that  celebrated  anatomist  is  so  anxious 
throughout  his  various  works  to  establish  be- 
tween what  he  terms  "  contractility  of  tissue" 
and  elasticity,  appears  to  us  unfounded.  Elas- 


ticity according  to  him  is  a  purely  physical 
property.  Contractility  of  tissue,  though  not 
actually  a  vital  one,  is  however  found  only  in 
the  animal  tissues;  it  does  not  depend  directly 
upon  life,  but  results  merely  from  the  texture 
and  organization  of  those  particles  which  con- 
stitute the  vital  organs.  The  following  passage 
from  his  work  upon  "  Life  and  Death"  may, 
perhaps,  assist  us  in  understanding  his  views 
upon  this  subject.  "  Most  organs  of  our 
bodies  are  held  in  a  state  of  tension  by  various 
causes ;  the  voluntary  muscles  by  their  anta- 
gonists ;  the  hollow  muscles  by  the  substances 
contained  within  them ;  the  vessels  by  means 
of  their  circulating  fluids;  the  skin  of  one 
portion  of  the  body  by  that  which  covers  the 
neighbouring  part;  the  alveolar  walls  by  the 
teeth  contained  within  them.  Now,  upon  the 
suspension  of  the  distending  causes,  contrac- 
tion takes  place:  divide  a  long  muscle, — its 
antagonist  becomes  shortened;  empty  a  hol- 
low muscle,  it  shrinks  upon  itself:  prevent  the 
blood  from  entering  an  artery,  the  vessel  be- 
comes a  ligament:  cut  through  the  integu- 
ments, the  divided  edges  are  separated  from 
each  other  by  the  contraction  of  the  adjoining 
skin  :  extract  a  tooth  from  its  alveolus,  that 
channel  becomes  obliterated.  *  *  *  In  all  these 
cases  it  is  the  removal  of  a  tension  naturally 
inherent  in  the  tissue  which  determines  its 
contraction: — in  other  instances  it  is  the  re- 
moval of  a  tension  which  does  not  naturally 
reside  in  the  part.  Thus  we  see  the  abdomen 
contract  after  parturition ;  the  maxillary  sinus 
after  the  extirpation  of  a  fungous  growth ;  the 
cellular  tissue  after  the  removal  of  an  abscess ; 
the  tunica  vaginalis  after  the  operation  for 
hydrocele;  the  integument  of  the  scrotum 
after  the  removal  of  an  enlarged  testicle ;  the 
aneurismal  sac  upon  the  emptying  of  its  fluid." 
He  remarks  in  another  place  that  motion 
when  the  result  of  elasticity  is  quick  and  sud- 
den, and  ceases  as  abruptly  as  it  has  been  pro- 
duced; but  the  motions  which  result  from 
contractility  of  tissue  are  slow  and  impercep- 
tible, lasting  frequently  for  hours  and  even 
days,  as  are  seen  in  the  retraction  of  muscles 
after  amputation.  The  distinction  laid  down 
in  these  passages  appears  to  us  totally  un- 
supported :  to  say,  for  example,  that  even  in  a 
dead  artery  there  are  two  principles  of  con- 
traction which,  though  their  mode  of  action  is 
literally  the  same,  should  nevertheless  be  con- 
sidered distinct  and  referred  to  different  sources 
appears  contrary  to  every  rule  of  philosophic 
reasoning.  As  to  the  distinction  drawn  from 
the  comparative  quickness  of  these  motions, 
it  is  only  necessary  to  say  that  upon  this  view 
of  the  subject  even  the  movement  of  the 
watch-spring  itself  cannot  be  attributed  to  elas- 
ticity. We  must  then  conclude  that  there  are 
two  and  only  two  forces  to  which  all  the 
various  movements  of  living  bodies  can  be 
referred  ;  the  one  a  vital  force  regulated  by  its 
own  proper  laws,  the  other  a  general  physical 
property,  whose  mode  of  action  is  essentially 
the  same  in  organized  and  unorganized  bodies  : 
the  phenomena  above  enumerated  by  Bichat 


58 


ELASTICITY. 


are  certainly  not  the  result  of  vital  action  (for 
he  admits  that  the  contractility  of  tissue  to 
which  he  ascribes  them  is  not  destroyed  by 
death) :  they  must  then  be  owing  to  a  physical 
force,  and  amongst  the  various  physical  agen- 
cies we  are  acquainted  with,  elasticity  is  the 
only  one  to  which  they  can  be  referred. 

The  "  vis  tnortua"  of  Haller  appears  like- 
wise to  differ  little  if  at  all  from  elasticity. 
Speaking  of  this  force  he  observes,  that,  as 
indeed  the  very  name  implies,  it  is  totally  in- 
dependent of  life,  and  adds — "  Haec  vis  in 
partibus  animalium  perpetuo  agere  videtur, 
etiamsi  non  perpetuus  effectus  adparet.  Vi- 
detur enim  contractio  cuique  particulae  propria 
a  contraria  contractione  duorum  elementorum 
vicinorum  impugnari  et  distrahi,  ut  qua? 
breviores  fieri  non  possunt,  quin  mediam  par- 
ticulam  distrahant.  Id  dum  fit  in  omnibus, 
quies  videtur,  quae  est  summa  virium  contra- 
riarum  se  destruentium.  Quam  primum  vero 
aliqua  particula  a  sodalibus  separatur,  inflicto 
vulnere,  tunc  utique  labium  vulneris,  nunc 
liberum,  nec  a  contraria  potestate  retentum,  se 
ad  earn  vicinam,  a  qua  trahitur,  integramque 
incisa?  membranae  partem  retrahit."  The  facts 
so  accurately  described  in  this  passage  are 
easily  explained  by  the  operation  of  elasticity. 
Why  then  multiply  causes  ?  Why  assume  the 
existence  of  another  principle  in  order  to  ac- 
count for  them  ?  The  phenomena  ascribed  by 
Cullen  and  others  to  what  he  terms  "  tonicity," 
are  also,  at  least  in  many  instances,  the  effects 
of  the  same  physical  force.  (See  Contrac- 
tility.) 

II.  The  tissues  of  the  animal  body  are  pos- 
sessed of  very  various  degrees  of  elasticity; 
some  of  them  are  but  little  inferior  to  the  most 
highly  elastic  unorganized  substances,  while 
others  are  endowed  with  this  property  in  so 
very  trifling  a  degree,  that  in  our  physiological 
and  pathological  reasonings  concerning  them, 
we  may  almost  consider  it  as  absent.  We 
shall  endeavour  to  arrange  the  principal  organic 
tissues  in  the  order  of  their  elasticity,  and  shall 
then  proceed  to  offer  a  few  remarks  upon  each. 

1.  Yellow  fibrous  tissue.  2.  Cartilage.  3. 
Fibro-cartilage.  4.  Skin.  5.  Cellular  mem- 
brane. 6.  Muscle.  7.  Bone.  8.  Mucous 
membrane.  9.  Serous  membrane.  10.  Ner- 
vous matter.    11.  Fibrous  membrane. 

This  view  of  the  comparative  elasticity  of 
the  different  tissues  must  not  be  regarded  as 
rigorously  exact :  owing  to  the  impossibility 
of  procuring  each  one  perfectly  separate  from 
the  others,  the  result  of  our  experiments  can  be 
considered  merely  as  approximate. 

1.  The  yellow  fibrous  system. — The  tissues 
composing  this  system  are  unquestionably  the 
most  highly  elastic  of  all :  the  ligamenta  sub- 
flava  which  unite  the  laminae  of  the  vertebrae 
to  one  another,  and  the  ligamentum  nuchas 
which  suspends  the  head  in  some  of  the  larger 
quadrupeds,  are  scarcely  inferior  to  caoutchouc 
in  this  respect.  The  middle  coat  of  arteries 
is  referred  by  Beclard  to  the  yellow  fibrous 
system,  perhaps  from  its  possessing  in  so  high 
a  degree  this  characteristic  property.    Its  exis- 


tence may  be  demonstrated  by  various  experi- 
ments, and  many  of  the  physiological  and 
pathological  phenomena  of  the  arterial  tissue 
are  modified  or  determined  by  its  presence. 
The  sudden  expansion  of  an  artery  whether  in 
the  living  or  dead  body  upon  the  removal  of 
a  force  pressing  its  sides  together ;  the  gradual 
contraction  of  a  divided  artery,  by  means  of 
which  hemorrhage  is  so  frequently  arrested ; 
the  contraction  or  obliteration  of  the  vessel 
beyond  the  ligature,  after  it  has  been  taken  up 
in  aneurism  ;  the  obliteration  of  the  umbilical 
arteries  and  of  the  ductus  arteriosus  soon  after 
birth  ;  the  gaping  which  occurs  in  longitudinal 
wounds  of  arteries  owing  to  the  recession  of 
the  divided  edges;  the  power  possessed  by  these 
vessels  of  accommodating  their  size  to  the 
quantity  of  circulating  blood,  (thus  causing 
endless  variations  in  the  volume  of  the  pulse 
even  in  the  same  individual) ; — all  these  facts 
have  been  accounted  for  by  the  transverse 
elasticity  of  the  middle  coat.  The  effects  of 
this  property  in  a  longitudinal  direction  may 
be  seen  in  the  retraction  of  divided  arteries 
during  amputation  ;  in  the  sort  of  locomotion 
which  these  vessels  undergo  from  the  impulse 
of  the  blood,  and  in  the  enlargement  of  a 
transverse  arterial  wound  by  the  retraction  of 
its  edges.  The  proper  coat  of  veins,  though 
belonging  likewise  to  this  system,  is  however 
much  less  elastic  than  that  of  the  arteries  ;  but 
we  cannot  agree  with  those  who  deny  this 
property  to  the  venous  tissue.  The  sudden 
flow  of  blood  from  a  portion  of  vein  included 
between  two  ligatures  ;  the  constantly  varying 
size  of  the  cutaneous  veins  according  to  the 
volume  of  their  contents ;  the  obliteration 
under  certain  circumstances  of  veins  where 
circulation  has  been  arrested,  appear  to  us 
explicable  only  by  attributing  this  property  to 
them. 

2.  Cartilage  is  possessed  of  very  great  elas- 
ticity. On  pressing  the  point  of  a  scalpel 
into  cartilage  it  is  expelled  upon  the  suspension 
of  the  force  by  the  contraction  of  the  sur- 
rounding substance.  It  may  also  be  well  de- 
monstrated by  twisting  or  bending  the  carti- 
lages of  the  ribs,  or  those  of  the  nose,  eyelid, 
&c.  The  elasticity  of  cartilage  in  the  adult  is 
much  greater  than  in  the  child  or  old  person. 
We  shall  allude  presently  to  the  several  impor- 
tant objects  to  which  this  property  as  connected 
with  cartilage  is  applied. 

3.  Fibro-cartilage. — The  elasticity  of  this 
tissue  may  be  studied  in  the  intervertebral 
fibro-cartilages,  in  which  it  contributes  so 
remarkably  to  the  obscure  movements  of  the 
spinal  column  and  to  the  security  of  the  chord : 
it  is  remarkably  displayed  in  restoring  the  sub- 
stance to  its  proper  condition,  when  pressure 
rather  than  twisting  or  bending  has  been  the 
cause  of  derangement.  The  fibro-cartilaginous 
funnels  through  which  the  tendons  are  trans- 
mitted, possess  likewise  this  property  to  a  great 
extent.  Bichat  found,  on  removing  a  tendon 
in  a  living  dog,  that  the  funnel  through  which 
it  had  been  transmitted  became  impervious, 
like  an  artery  under  similar  circumstances. 


ELASTICITY. 


59 


4.  Skin. — The  great  elasticity  of  the  cuta- 
neous tissue  is  exhibited  in  innumerable  in- 
stances; the  extension  which  it  undergoes  in 
pregnancy,  in  ascites,  in  cases  of  large  fatty 
and  other  tumours,  and  the  promptitude  with 
which  in  these  instances  it  returns  to  its  proper 
state  after  the  removal  of  the  distending  causes, 
are  matters  of  every  day  observation,  and  are 
chiefly  owing  to  its  elasticity.  The  great  re- 
traction of  the  integuments  in  amputation 
depends  likewise  upon  the  same  principle. 
There  is  perhaps  no  tissue  in  the  body  where 
elasticity  is  more  impaired  by  advanced  age  : 
in  the  young  or  adult  subject,  when,  owing  to 
disease  or  other  causes,  the  subcutaneous  adi- 
pose matter  has  become  suddenly  absorbed, 
the  skin,  owing  to  its  great  elasticity,  is  ena- 
bled to  contract,  and  thus  accommodate  itself 
to  the  diminished  distention  ;  while  in  old  age, 
under  the  same  circumstances,  the  power  of 
contraction  is  lost,  and  hence  it  hangs  in  loose 
folds  or  wrinkles,  so  characteristic  of  that 
period  of  life.  These  remarks  are  meant  to 
apply  chiefly  to  the  true  skin  or  corion. 

5.  Cellular  tisme  ranks  high  among  the 
elastic  structures  :  many  of  the  cases  which 
we  have  just  instanced  as  proving  the  elasticity 
of  the  cutaneous  tissue,  indicate  likewise  its 
existence  in  the  cellular  membrane;  anasarca, 
oedema,  and  still  more  emphysema,  can  occur 
only  in  consequence  of  the  distention  of  those 
filamentous  threads  which  form  the  cells  ;  and 
as  recession  occurs  immediately  upon  the  re- 
moval of  the  distending  force,  it  is  plain 
that  elasticity  is  the  principle  to  which  the 
change  must  be  attributed.  We  may  likewise 
remark  that  there  is  no  tissue  whose  elasticity 
is  so  frequently  and  perhaps  so  usefully  em- 
ployed as  that  which  we  are  now  considering ; 
for  it  is  by  this  property  of  cellular  membrane 
that  the  motion  of  the  several  muscles  is  per- 
mitted and  even  assisted  :  thus  upon  elevating 
the  arm  the  yielding  cellular  tissue  of  the 
axilla  permits  the  member  to  be  drawn  up- 
wards, and  when  the  arm  is  again  depressed 
the  elasticity  of  the  same  tense  filaments  as- 
sists in  some  degree  the  muscles  which  bring 
it  down. 

6.  Muscle. — Elasticity  appears  to  belong  to 
the  muscular  system  in  a  very  high  degree  ;  it 
is,  however,  extremely  difficult  to  estimate  its 
extent  in  the  muscular  fibre  itself,  partly  owing 
to  its  being  the  seat  of  two  other  contractile 
forces,  the  vis  insita  and  vis  nervea,  and  partly 
to  the  great  quantity  of  cellular  and  other  tis- 
sues which  enter  into  the  structure  of  muscle, 
and  thus  impart  to  it  their  physical  properties. 
There  are  however  many  instances  in  which  we 
must  concede  elasticity  to  the  muscular  fibre  ; 
the  contraction  which  occurs  in  the  abdominal 
muscles  even  long  after  death,  upon  removing 
the  accumulation  of  air  or  fluid  contained 
within  the  peritoneum;  and  the  recession  of 
the  cut  edges  which  takes  place  upon  dividing 
a  muscle  under  the  same  circumstances,  cannot 
be  ascribed  either  to  the  vis  nervea  or  to  the 
vis  insita,  (for  they  have  ceased  to  exist,)  and 
the  contraction  is  evidently  too  extensive  to  be 


attributed  wholly  to  the  cellular  tissue.  But 
we  may  observe  the  operation  of  this  property 
even  in  the  living  muscles  :  on  dividing  the 
facial  muscles  of  one  side  in  a  living  animal 
the  mouth  is  gradually  drawn  towards  the 
opposite,  and  this  takes  place  not  by  the 
effort,  but  solely  by  the  elasticity  of  the  un- 
injured muscles,  which  have  now  no  coun- 
teracting force  upon  the  other  side  to  resist 
their  contraction.  So  it  is  with  all  the  other 
muscles  during  what  is  called  their  state  of 
rest :  the  elasticity  of  one  class  is  exactly  ba- 
lanced by  the  same  property  in  their  antago- 
nists; and  hence  when  the  influence  of  the 
will  is  completely  withdrawn,  as  in  sleep,  we 
may  estimate  the  comparative  quantity  of  elas- 
ticity which  antagonizing  muscles  are  possessed 
of :  those  of  the  face  for  example  are  exactly 
equal  upon  opposite  sides  in  this  respect,  and 
accordingly  the  mouth  retains  its  proper  central 
position  ;  but  in  the  limbs,  as  the  elasticity  of 
the  flexors  exceeds  that  of  the  extensors,  we 
usually  find  these  parts  of  the  body  during 
sleep  in  a  semiflexed  position. 

7.  Bone  possesses  considerable  elasticity, 
though  its  degree  is  frequently  underrated  by 
the  superficial  observer.  It  is  not  easily  demon- 
strable in  the  larger  bones,  but  upon  cutting 
even  these  into  thin  plates  its  existence  becomes 
at  once  evident.  There  are  many  phenomena 
both  healthy  and  diseased  which  depend  upon 
the  elasticity  of  bone ;  the  enlargement  of  the 
maxillary  sinus  from  the  growth  of  fungus 
within  its  cavity,  and  the  collapse  of  its  walls 
upon  the  removal  of  the  distending  matter;  the 
obliteration  of  the  alveolus  after  the  extraction 
of  a  tooth ;  the  narrowing  of  the  optic  hole 
which  is  found  in  cases  of  atrophy  of  the  optic 
nerves,  and  of  the  carotid  canal  after  tying  the 
carotid  artery  ;  the  diminution  of  the  orbital 
cavity  which  gradually  takes  place  upon  extir- 
pation of  the  eye — all  these  changes  depend  in 
a  great  degree  upon  the  elastic  qualities  of  bone. 
The  great  elasticity  of  the  osseous  system  in  the 
young  subject,  and  the  almost  entire  absence  of 
it  in  the  bones  of  old  persons,  is  at  once  ex- 
plained by  the  fact  that  elasticity  resides  in  the 
cartilaginous  and  not  in  the  earthy  ingredient ; 
the  great  proportion  of  the  former  in  the  young 
bone,  and  the  accumulating  deposition  of  earthy 
matter  as  age  advances,  are  known  to  every 
observer. 

8.  Mucous  membrane. — That  this  tissue  is 
possessed  of  some  degree  of  elasticity  would 
appear  from  the  well-known  contraction  which 
is  found  in  the  lower  part  of  the  intestinal  canal 
after  the  establishment  of  an  artificial  anus; 
from  the  great  variation  of  size  which  is  observed 
in  the  stomach,  and  by  means  of  which  it  can 
accomodate  itself  to  the  quantity  of  food  con- 
tained within  it;  and  from  many  other  simi- 
lar instances.  But  in  these  cases  it  is  often 
difficult  to  determine  how  far  contraction  de- 
pends upon  the  mucous  membrane,  or  upon  the 
other  tissues  with  which  it  is  associated.  We 
should  also  bear  in  mind  that  the  contraction  of 
the  inner  coat  of  the  stomach  is  much  less 
than  might  in  the  first  instance  be  supposed  ; 


60 


ELASTICITY. 


the  numerous  folds  or  rugee  into  which  it  is 
thrown  seem  destined  to  compensate  for  its  im- 
perfect elasticity. 

9.  Serous  membrane  is  still  lower  in  the 
scale.  In  those  organs  whose  size  is  subjected 
to  frequent  variation,  such  as  the  stomach,  in- 
testines, urinary  bladder,  &c,  we  find  an  inter- 
esting provision  to  permit  enlargement  without 
at  all  stretching  their  serous  envelope.  The 
organ,  instead  of  possessing  a  simple  serous 
capsule,  is  inserted  between  two  loosely  adher- 
ent folds  of  peritoneum  which  permit  its  insinu- 
ation between  them  as  soon  as  distension  takes 
place.  By  this  simple  contrivance  the  possibi- 
lity of  rupture  or  even  tension  of  the  serous  coat 
is  completely  obviated,  even  in  cases  of  extreme 
enlargement.  The  tunica  vaginalis  testis 
would  appear  to  possess  more  elasticity  than 
other  membranes  of  this  class : — after  the  ope- 
ration for  hydrocele,  a  disease  in  which  it  is 
distended  far  beyond  its  proper  limits,  a  sudden 
contraction  of  its  tissue  evidently  occurs. 

10.  Nervous  matter. — Upon  the  division  of 
a  nerve  little  or  no  retraction  of  the  divided  ex- 
tremities takes  place.  The  brain  however 
possesses  an  obscure  elasticity,  as  may  be  seen 
upon  making  a  horizontal  section  of  its  sub- 
stance :  the  numerous  red  points  which  there 
present  themselves  are  owing  to  the  blood  forced 
from  the  divided  vessels  by  the  surrounding 
pressure. 

11.  Fibrous  membrane  is  remarkable  for 
its  very  low  degree  of  elasticity;  hence  liga- 
ments and  tendons  often  give  way  rather  than 
yield  to  a  distending  force.  It  is  owing  to  the 
unyielding  nature  of  the  subcutaneous  fascia  in 
some  situations  that  abscesses  and  other  swel- 
lings occurring  beneath,  produce  but  little  swel- 
ling upon  the  surface,  and  cause  such  severe 
pain  to  the  patient;  hence  too  upon  dividing 
this  fascia,  no  enlargement  of  the  wound  occurs 
as  in  other  tissues  by  the  elastic  retraction  of  its 
edges.  When  the  distending  force  however 
is  slowly  applied,  there  appears  to  exist  some 
degree  of"  elasticity  even  in  fibrous  membranes  ; 
thus  in  hydrops  articuli  the  structures  about  the 
joint  are  frequently  much  distended  by  the  ac- 
cumulation of  fluid  within,  upon  the  absorption 
of  which  they  slowly  resume  their  proper  con- 
dition. 

III.  We  shall  now  proceed  to  point  out 
some  instances  in  which  elasticity  plays  an  im- 
portant part  in  the  mechanism  of  organized 
beings ;  but  it  may  be  necessary  to  remark  that 
in  doing  so  we  by  no  means  profess  to  give  an 
anatomical  description  of  the  various  structures 
alluded  to.  We  shall  endeavour  merely  to  bring 
into  one  general  view  some  of  the  most  inter- 
esting cases  in  which  elasticity  plays  a  prominent 
part,  and  thus  enable  the  reader  to  refer  to  the 
separate  articles  in  which  these  details  are  fully 
discussed. 

Nature  avails  herself  of  this  physical  property 
in  the  construction  of  organized  bodies,  for 
several  distinct  ends.  It  is  sometimes  employed 
as  a  means  of  protecting  certain  delicate  and 
important  organs  by  bearing  off  or  decomposing 
the  forces  to  which  they  are  exposed.    It  is 


often  used  to  economise  muscular  contraction, 
not  only  in  supporting  depending  parts,  but 
likewise  in  effecting  the  movement  of  one  por- 
tion of  the  body  upon  another.  In  some  instan- 
ces it  is  rendered  subservient  to  the  general 
movement  of  the  body,  or  locomotion.  By  elas- 
ticity the  proper  patulous  condition  of  certain 
canals  and  outlets  is  secured ;  and  lastly,  it  very 
often  serves  to  divide  the  power  of  particular 
muscles  or  sets  of  muscles,  and  thus  to  transfer 
the  contractile  force  from  one  portion  of  an  ap- 
paratus to  another. 

1.  Elasticity  is  employed  by  nature  as  a 
means  of  protecting  the  body  generally,  or  some 
of  its  organs  more  particularly,  against  external 
violence.  The  great  elasticity  of  the  various 
tissues  in  the  young  subject,  and  of  the  osseous 
system  especially,  affords  at  that  period  of  life  no 
inconsiderable  security  to  the  whole  system  : 
the  bones  themselves  can  yield  in  a  very  great 
degree  to  external  impressions  and  thus  prevent 
their  bad  effects.  The  frequent  and  apparently 
dangerous  falls  of  children,  and  the  perfect  im- 
punity with  which  they  are  encountered,  are 
known  to  every  one,  and  can  easily  be  accounted 
for  by  the  great  elasticity  of  the  tissues  at  that 
period  of  life.  The  opposite  extreme  of  human 
existence,  in  which  we  meet  with  the  reverse  of 
these  conditions,  is  equally  illustrative  of  our 
subject ;  for  then  the  bones,  owing  to  the  pro- 
gressive accumulation  of  earthy  matter,  have  al- 
most lost  their  power  of  yielding,  and  hence  a 
very  slight  force  is  sufficient  to  fracture  them. 
But  elasticity  plays  a  still  more  important  part 
in  protecting  certain  organs,  such  as  the  spinal 
chord,  whose  structure  is  so  delicate  that  it  may 
be  torn  by  the  slightest  violence,  and  whose  func- 
tion is  frequently  deranged  even  by  mere  con- 
cussion. The  mechanism  of  the  vertebral  column 
exhibits  at  every  step  the  most  admirable  appli- 
cation of  elasticity  to  the  protection  of  its  con- 
tents. An  unskilful  mechanic  who  sought  to 
afford  the  greatest  security  to  this  contained  or- 
gan might  naturally  enough  suppose  that  its 
safety  would  be  proportionate  to  the  strength 
and  density  of  the  material  which  he  should 
employ  in  incasing  it ;  he  would  probably 
have  thrown  around  it  a  strong  cylinder  of  solid 
bone,  such  as  we  see  employed  for  a  different 
object  in  the  tibia  or  femur.  But  the  condition 
of  old  age  again  affords  us  a  complete  refutation 
of  such  reasonings ;  the  spinal  column  by  the 
successive  consolidation  of  its  component  parts 
is  then  in  fact  converted  into  one  long  cylinder 
of  extraordinary  strength ;  it  has  become  literally 
a  single  bone ;  but  now  every  touch  upon  the 
surface  of  the  body,  every  application  of  the  foot 
upon  the  ground,  is  conveyed  by  the  solid  and 
almost  inelastic  bones  to  the  spinal  cord,  thus 
rendering  even  the  movements  of  progression  a 
source  of  pain ;  hence  repose  is  the  natural  con- 
dition of  this  period  of  life,  as  restless  activity  is 
that  of  childhood.  But  looking  at  the  spinal 
column  in  the  active  or  adult  age  we  perceive  a 
totally  different  mechanism  ;  it  now  consists  of 
no  less  than  twenty-four  distinct  bones  piled  one 
upon  the  other  and  connected  by  twenty-four 
layers  of  fibro-cartilage,  a  tissue,  as  we  have  al- 


ELASTICITY. 


61 


ready  seen,  possessed  of  extraordinary  elasticity. 
The  chord,  instead  of  filling  the  whole  cavity,  is 
suspended  within  it  by  means  of  an  elastic  liga- 
ment; and  thus  this  delicate  cylinder  of  nervous 
matter  is  hung  loosely  upon  a  series  of  elastic 
springs  which  effectually  break  the  many  jolts 
and  concussions  incident  to  the  frame  in  the 
various  movements  of  active  life.  It  is  owing 
to  this  extreme  elasticity  of  the  spinal  column, 
that  even  after  very  long-continued  pressure,  it 
soon  recovers  its  proper  condition.  When,  for 
instance,  from  long  and  severe  exercise  the  fibro- 
cartilages  have  become  somewhat  pressed  down 
by  the  superincumbent  weight,  a  few  hours' 
repose  in  the  horizontal  position  is  sufficient  to 
restore  the  spine  to  its  proper  length.  This  fact 
has  not  escaped  the  shrewd  practical  observa- 
tion of  the  lower  classes  ;  when  admission  into 
the  army  can  be  obtained  only  by  persons  of  a 
certain  stature,  the  candidate  who  apprehends 
he  can  spare  nothing  in  that  particular,  usually 
presents  himself  after  his  night's  repose.  The 
delicate  viscera  of  the  thoracic  cavity  owe  like- 
wise their  safety  in  a  great  degree  to  the  same  me- 
chanism. The  cartilages  which  connect  the  ribs 
and  sternum,  and  which,  as  we  shall  presently 
find,  are  destined  to  modify  the  movements  of 
the  thorax,  tend  likewise  to  its  security  by  per- 
mitting it  to  yield  to  external  forces.  The  ob- 
scure elasticity  of  the  ribs  themselves  and  of  the 
ligaments  connecting  them  to  the  spine  contri- 
bute to  the  same  end ;  hence  we  seldom  find 
the  thoracic  viscera  ruptured  even  by  the  greatest 
violence  applied  against  their  walls.  It  is  this 
elasticity,  aided  no  doubt  by  other  still  more 
efficient  causes,  which  enables  the  mountebank 
to  receive  with  impunity  the  blows  of  the 
weightiest  sledge  on  an  anvil  laid  upon  his 
chest. 

2.  Elasticity  is  often  had  recourse  to  as  a 
substitute  for  muscular  contraction,  and,  as  it 
would  appear,  with  a  view  to  economize  that 
more  important  property.  We  find,  for  ex- 
ample, that  in  most  animals  the  abdominal 
viscera  are  supported  in  their  position  chiefly 
by  the  muscles  of  the  abdomen,  and  that  on 
being  forced  downwards  in  inspiration  by  the 
descent  of  the  diaphragm,  they  are  again 
pressed  upwards  by  the  contraction  of  these 
muscles.  In  the  large  ruminating  quadrupeds 
whose  abdominal  viscera  are  of  so  great  a  size, 
and  in  whom,  owing  to  the  horizontal  position 
of  the  trunk,  these  organs  tend  directly  down- 
wards, the  quantity  of  muscular  power  requi- 
site to  support  and  move  them  should  neces- 
sarily have  been  of  great  amount ;  but  instead 
of  increasing  the  quantity  of  muscle  to  such 
an  extent,  nature  has  effected  her  purposes 
by  much  more  simple  means.  Beneath  the 
abdominal  integuments  there  exists  a  mem- 
brane of  great  strength  and  elasticity,  which 
not  only  supports  the  viscera  but  also  helps 
to  elevate  them  after  they  have  been  forced 
downwards  in  inspiration.  The  elastic  liga- 
mentum  nucha,  which  in  these  animals  sup- 
ports the  very  weighty  head,  is  a  simple  but 
complete  substitute  for  the  great  mass  of 
muscle  which  should  have  existed  on  the  back 


part  of  the  neck,  in  order  to  effect  the  same 
end.  So  obviously  in  this  instance  is  elasticity 
a  substitute  for  muscularity,  that  upon  com- 
paring the  structure  in  various  animals  we  find 
the  strength  and  elasticity  of  the  ligament 
always  proportionate  to  the  weight  of  the  head 
which  it  has  to  support.  In  the  carnivora  an 
interesting  application  of  this  property  is  seen 
in  the  retractile  ligament  passing  between  the 
claw  and  the  phalangeal  bone ;  as  the  claw  in 
many  genera  is  the  chief  weapon  of  attack,  it 
must  not  be  suffered  to  come  into  contact  with 
the  ground  in  progression,  for  otherwise  it 
would  become  blunted,  as  seen  in  those  which 
do  not  use  it  for  the  purposes  mentioned;  it  is 
consequently  suspended  by  the  retractile  liga- 
ment until  drawn  down  at  the  will  of  the  animal 
by  means  of  the  flexor  muscles.  Elasticity  is 
here  used  as  the  means  of  suspension  in  order 
to  save  the  effort  of  a  constant  muscular  exer- 
tion. In  the  mollusea  we  see  this  property 
again  employed  to  economize  muscularity : 
the  shell  of  the  oyster  admits  of  being  opened 
as  well  as  closed  at  the  will  of  the  animal ; 
but  muscularity  is  the  source  of  the  one  ac- 
tion; elasticity  residing  in  a  strong  ligament  is 
the  means  of  effecting  the  other. 

3.  Elasticity  frequently  preserves  the  patu- 
lous condition  of  certain  outlets  in  the  animal 
body,  as,  for  example,  those  of  the  eyes  and 
nostrils.  This  object  is  attained  by  the  inser- 
tion of  a  rim  of  highly  elastic  cartilage  into 
the  soft  parts  which  bound  these  openings.  A 
material  of  greater  rigidity,  such  as  bone, 
would,  it  may  be  objected,  have  answered  the 
purpose  still  better:  but  the  rigidity  of  that 
substance  would  have  greatly  interfered  with 
the  free  movements  necessary  for  the  functions 
of  the  lids,  and  in  the  nose  would  not  only 
have  increased  the  risk  of  injury  from  external 
violence,  but  would  have  prevented  the  ap- 
proximation of  the  alse  which  must  take  place 
in  order  to  expel  the  nasal  mucus.  Neither 
would  a  soft  and  inelastic  material  have  an- 
swered the  purpose,  for  then  the  first  effect  of 
inspiration  would  be  to  approximate  the  edges 
of  the  opening,  and  thus  to  prevent  the  further 
entrance  of  air.  The  tracheal  and  bronchial 
canals  are  likewise  preserved  patulous  by  the 
same  elastic  material ;  and  we  again  meet  with 
it  performing  a  like  office  in  the  Eustachian 
tube  and  the  external  meatus  of  the  ear. 

4.  Elasticity  is  sometimes  rendered  subser- 
vient to  locomotion,  or  the  general  movement 
of  the  body.  The  elastic  pad  placed  beneath 
the  foot  of  the  dromedary  and  many  other  ani- 
mals is  no  doubt  intended  to  facilitate  progres- 
sion, and  to  compensate  in  some  degree  for 
the  yielding  looseness  of  the  sands  upon  which 
they  tread.  The  same  apparatus  is  found  in 
very  great  perfection  in  the  feet  of  the  carni- 
vora, and  must  be  of  great  use  in  enabling 
them  to  make  those  enormous  bounds  by  which 
they  spring  upon  their  prey.  But  perhaps  one 
of  the  most  interesting  examples  of  elasticity 
being  rendered  subservient  to  locomotion  is 
met  with  in  certain  fish.  The  salmon,  during 
its  annual  ascent  to  fresh-water  streams  for  the 


62 


REGION  OF  THE  ELBOW. 


purpose  of  depositing  its  spawn,  often  encoun- 
ters cataracts  of  great  height,  and  which 
would  seem  to  render  farther  progress  impos- 
sible. By  means,  however,  of  a  powerfully 
muscular  tail  and  elastic  spine  it  is  enabled  to 
surmount  those  obstacles ;  resting  one  side 
upon  a  solid  fulcrum,  it  seizes  its  tail  between 
its  teeth,  and  thus  draws  itself  into  an  arch  of 
amazing  tension  ;  then  suddenly  letting  go  its 
hold,  and  thus  freeing  the  elastic  spring  which 
its  body  represented,  it  is  thrown  into  the  air, 
often,  as  Twiss  has  seen  in  Ballyshannon  in 
Ireland,  to  a  height  of  twelve  or  fifteen  feet, 
and  falls  beyond  the  obstacle  which  had  op- 
posed it. 

5.  Elasticity  becomes  occasionally  in  the 
animal  machine  a  means  of  dividing  muscular 
force,  and  thus  transferring  it  from  one  portion 
of  an  apparatus  to  another.  The  muscles  of 
inspiration  are,  if  we  may  use  the  word,  too 
strong  for  their  opponents,  and  hence  it  be- 
comes necessary  to  transfer  a  portion  of  their 
superfluous  strength  to  the  weaker  set.  This 
is  effected  by  means  of  the  elastic  cartilages 
which  connect  the  ribs  and  sternum.  The  in- 
spiratory muscles  in  enlarging  the  thorax  act 
with  such  a  force  that  they  not  only  elevate  the 
ribs,  but  even  stretch  and  twist  the  cartilages, 
and  hence  no  sooner  is  inspiration  completed 
than  elasticity  conies  into  play,  tending  to  depress 
the  ribs  and  thus  to  assist  the  weaker  muscles. 
But  we  must  not  fall  into  the  error  of  suppo- 
sing that  elasticity  is  in  this  case  a  substitute 
for  muscularity,  and  much  less  that  it  is  in 
itself  a  source  of  power.  The  only  power 
exercised  by  it  is  that  which  it  has  just  bor- 
rowed from  the  inspiratory  muscles :  had  not 
the  elasticity  of  the  cartilages  been  set  in  action 
by  this  external  agency,  it  would,  like  the  elas- 
ticity of  the  watch-spring  under  the  same  cir- 
cumstances, have  remained  for  ever  dormant. 
In  those  interesting  discussions  which  have 
arisen  of  late  years  relative  to  what  is  termed 
the  suction  power  of  the  heart,  we  apprehend 
that  much  error  has  arisen  from  overlooking 
this  simple  law  of  elasticity.  That  doctine 
will  of  course  be  fully  stated  and  examined 
in  its  proper  place ;  at  present  we  shall  merely 
observe  that  it  was  first  regularly  put  forward 
in  the  admirable  work  of  Dr.  Wilson  Philip, 
that  it  was  followed  up  and  explained  by  Dr. 
Carson,  and  that  these  views  were  regarded  by 
Laennec  with  such  respect  that  he  pronounces 
their  discovery  the  most  important  step  made 
in  this  department  of  physiology  since  the 
time  of  Harvey.  The  heart,  it  is  said,  is  not 
merely  a  forcing  pump  which  by  the  contrac- 
tion of  its  ventricle  propels  the  blood  through- 
out the  arteries  ;  it  is  likewise  a  suction  pump, 
for  by  the  expansion  of  the  auricles  it  draws  in 
the  blood  from  the  veins.  Now  this  expansive 
force,  if  indeed  it  exist  at  all,  is,  we  are  quite 
satisfied,  merely  the  effect  of  the  heart's  elas- 
ticity; for  the  reasonings  of  those  who  attempt 
to  prove  it  of  a  specific  nature  are  evidently 
insufficient.  In  this  point  of  view  the  heart's 
expansion  cannot  be  regarded  as  a  new  and 
independent  power;  if  that  organ  be  really 


elastic,  then  the  muscular  force  of  its  systole 
must  be  greater  than  it  would  otherwise  have 
been,  for  it  has  not  only  to  propel  the  blood 
through  the  arterial  system,  but  likewise  to 
overcome  the  resisting  elasticity  of  its  own 
structure:  this  suction  power  of  the  heart  is 
then  merely  the  recoil  of  the  surplus  force ; 
what  is  gained  upon  the  one  hand  is  lost  upon 
the  other ;  and  hence  elasticity  in  this  instance 
cannot  be  regarded  as  an  independent  prin- 
ciple contributing  to  the  blood's  motion,  but 
merely  as  a  means  of  dividing  muscular  power 
and  transferring  a  portion  of  it  from  the  begin- 
ning of  the  arterial  to  the  end  of  the  venous 
system. 

6.  An  interesting  application  of  elasticity  in 
the  animal  machine  is  to  convert  an  occasional 
or  intermitting  force  into  a  continued  one.  As 
human  ingenuity  has  long  since  discovered  the 
application  of  this  principle,  we  may  see  it 
employed  in  many  mechanical  contrivances. 
In  the  common  fire-engine,  for  instance,  we 
observe  that  though  it  is  worked  by  interrupted 
jerks,  yet  the  water  issues  from  its  pipe,  not 
per  saltum  as  we  should  have  expected,  but  in 
one  uniform  and  continued  stream.  This  is 
effected  by  causing  the  fluid  to  pass,  in  the  first 
instance,  into  a  hermetically  sealed  vessel  con- 
taining a  portion  of  atmospheric  air  :  the  accu- 
mulation of  the  water  presses  the  air  into  a 
smaller  space,  but  in  doing  so  it  is  reacted 
upon  by  the  elasticity  of  that  gas,  which  may 
thus  be  considered  as  a  powerfully  elastic 
spring  exerting  upon  the  surface  of  the  water 
an  uniform  and  continual  pressure.  The  very 
same  principle  is  employed  in  the  mechanism 
of  the  arterial  system.  Upon  opening  one  of 
the  small  arteries  we  perceive  that  the  blood 
does  not  flow  per  saltum  as  in  those  which  are 
nearer  to  the  heart,  but  issues  in  an  uniform 
and  uninterrupted  stream.  The  intermitting 
action  of  the  heart  has  in  fact  been  converted 
into  a  continued  one  by  means  of  the  elasticity 
of  the  arterial  tissue.  We  might  indeed  say 
with  truth  that  the  blood  in  these  small  arteries 
is  not  directly  propelled  by  the  heart  at  all; 
the  force  of  that  organ  is  expended  in  distend- 
ing the  larger  elastic  arteries,  as  the  force  in  the 
fire-engine  is  expended  in  compressing  the  air. 
The  immediate  cause  of  motion  is  in  the  one 
case  the  reaction  of  the  elastic  air,  and  in  the 
other  the  reaction  of  the  elactic  artery. 

For  the  Bibliography  of  this  article,  see  that 
of  Fibrous  Tissue  and  Muscle. 

( Joint  E.  Bretian.) 

ELBOW,  REGION  OF  THE  ;  fold  or 
bend  of  the  arm.  (Fr.  plidubras;  coude.)  The 
region  of  the  elbow  is  situated  at  the  angular 
union  of  the  arm  with  the  fore-arm,  and  con- 
tains the  humero-cubital  articulation  and  the 
various  organs  which  surround  it :  the  extent 
of  this  region  may  be  determined,  superiorly 
by  a  circular  line  at  a  finger's  breadth  above 
the  internal  condyle,  and  inferiorly  by  a  similar 
line  at  two  fingers'  breadth  below  that  process : 
its  greatest  extent  is  in  the  transverse  direction, 
and  it  forms  an  angle  salient  posteriorly  and 


TtEGION  OF  THE  ELBOW. 


63 


retiring  in  front,  which  cannot  be  effaced  even 
in  the  utmost  extension  of  the  fore-arm.  The  ' 
anterior  surface  of  this  region  when  examined  in 
the  arm  of  a  muscular  man  presents  a  triangular 
depression,  in  which  is  observed  the  confluence 
of  several  large  subcutaneous  veins ;  the  base 
of  this  depression  is  above  ;  the  sides  are 
formed  by  two  prominences,  of  which  the  ex- 
ternal is  larger  and  more  marked  than  the  in- 
ternal, and  the  apex  of  the  triangle  is  formed 
inferiorly  by  the  convergence  of  these  pro- 
minences, which  consist  of  the  two  masses  of 
the  muscles  of  the  fore-arm  which  arise  from 
the  condyles  of  the  humerus.  This  triangular 
depression  is  divided  superiorly  into  two  por- 
tions by  a  prominence  formed  by  the  tendon 
of  the  biceps ;  in  the  external  or  larger  portion 
the  median  cephalic  vein  is  situated,  the  in- 
ternal is  occupied  by  the  oblique  course  of  the 
median  basilic  vein  and  the  trunk  of  the 
brachial  artery,  the  pulsations  of  which  can 
usually  be  felt  and  are  even  sometimes  visible 
in  this  space :  the  superficial  radial  or  cephalic 
vein  and  the  two  ulnar  veins  which  contribute 
to  form  the  basilic  are  also  apparent  in  this 
region,  being  situated  over  the  lateral  mus- 
cular prominences.  In  the  arm  of  a  corpulent 
female,  instead  of  the  appearances  here  de- 
scribed, the  front  of  the  elbow  presents  a 
semilunar  fold  or  depression,  the  concavity  of 
which  embraces  the  prominence  formed  by  the 
biceps. 

Laterally,  the  region  of  the  elbow  presents 
two  prominences  formed  by  the  condyles  of 
the  humerus,  of  which  the  internal  is  more 
marked  and  higher  than  the  external :  in  the 
arms  of  corpulent  persons,  on  the  contrary, 
two  depressions  like  dimples  are  placed  over 
the  condyles. 

Posteriorly,  the  olecranon  forms  a  remark- 
able prominence,  the  situation  of  which  varies 
in  its  relation  to  the  condyles  of  the  humerus 
according  to  the  different  motions  of  the  fore- 
arm ;  in  complete  extension  it  is  above  the 
level  of  these  processes,  in  semiflexion  it  is  on 
the  same  level  with  them,  and  is  below  them 
when  the  elbow  is  flexed  to  a  right  angle. 

On  either  side  of  the  olecranon  there  is  a 
depression  of  which  that  on  the  internal  side 
is  more  marked ;  pressure  here  produces  a 
painful  sensation  which  is  felt  in  the  little 
ringer  and  the  inner  side  of  the  ring-finger; 
in  the  depression  external  to  the  olecranon  the 
posterior  edge  of  the  head  of  the  radius  can 
be  felt  rotating  immediately  below  the  external 
condyle  when  pronation  and  supination  of  the 
fore-arm  are  performed.  An  accurate  know- 
ledge of  the  relations  of  these  parts  is  essential 
to  the  forming  an  accurate  diagnosis  in  cases 
of  fractures  and  dislocations  in  this  region. 

Skin  and  subcutaneous  tissue.  —  The  skin 
covering  this  region  is  thin,  smooth,  and  de- 
licate in  front ;  it  is  furnished  with  hairs  over 
the  lateral  prominences,  where  it  also  contains 
sebaceous  follicles  in  greater  numbers  than 
over  the  anterior  depression.  In  consequence 
of  being  very  vascular  and  plentifully  supplied 
with  nerves,  the  skin  here  is  prone  to  inflam- 


mation, and  is  often  the  seat  of  small  phlegmo- 
nous abscesses  and  of  erysipelas.  Posteriorly 
the  skin  is  thicker,  rough  on  the  surface,  and 
generally  thrown  into  transverse  folds  above 
the  olecranon,  particularly  in  extension :  it 
abounds  more  in  sebaceous  follicles  and  hairs 
here  than  on  the  anterior  surface.  The  sub- 
cutaneous cellular  tissue  in  front  consists  of 
two  layers :  one  of  these,  more  deep-seated, 
forms  a  sort  of  fascia,  between  the  layers  of 
which  the  subcutaneous  veins  and  nerves  are 
situated ;  the  other,  superficial,  is  principally 
composed  of  adipose  tissue  and  varies  very 
much  in  thickness.  In  lean  persons  this  latter 
layer  is  often  of  extreme  tenuity ;  while  the 
other,  on  the  contrary,  is  then  thicker  and  more 
closely  adherent  to  the  skin.  This  deeper 
layer  is  considerably  thicker  over  the  anterior 
angular  depression  than  on  the  lateral  pro- 
minences :  it  sinks  in  between  the  pronator 
radii  teres  and  supinator  longus  in  company 
with  the  deep  median  vein,  and  is  continuous 
with  the  cellular  tissue  between  the  muscles 
and  around  the  articulation.  Posteriorly  the 
subcutaneous  cellular  membrane  is  more  loose 
and  lamellar  :  adipose  tissue  is  almost  always 
absent  in  it  over  the  condyles  of  the  humerus, 
and  on  the  smooth  posterior  surface  of  the 
olecranon,  there  is  merely  a  subcutaneous 
bursa  mucosa  between  the  skin  and  the  peri- 
osteum. 

The  subcutaneous  cellular  tissue  in  front  of 
the  elbow  contains  some  large  veins,  besides 
lymphatics  and  filaments  of  cutaneous  nerves. 
As  the  subcutaneous  veins  in  this  region  are 
those  most  frequently  selected  by  surgeons 
for  the  operation  of  phlebotomy,  and  as  un- 
toward consequences  sometimes  result  from  a 
want  of  due  care  or  of  sufficient  anatomical 
knowledge  on  the  part  of  the  operator,  their 
situation  and  connexions  should  be  carefully 
studied. 

These  veins  are  subject  to  much  variety  in 
their  size,  number,  and  situation:  the  following 
arrangement  of  them  is  that  most  uniformly 
adopted  by  authors  as  the  normal  one :  three 
principal  veins  coming  from  the  fore-aim  enter 
the  lower  part  of  this  region:  1st,  the  radial 
or  cephalic  on  the  external  side  courses  along 
the  external  muscular  prominence  and  ascends 
to  the  arm  on  the  external  side  of  the  biceps  ; 
2d,  the  ulnar  or  basilic  ascends  over  the  in- 
ternal muscular  prominence  and  the  internal 
condyle  of  the  humerus  to  the  inner  side  of 
the  biceps;  3d,  the  median  vein  ascending 
from  the  front  of  the  fore-arm  enters  the  apex 
of  the  triangular  depression  of  the  elbow,  at 
which  point  it  is  usually  augmented  by  a  deep 
branch  coming  from  the  deep  radial  and  ulnar 
veins,  and  immediately  divides  at  an  acute 
angle  into  two  branches,  one  of  which  ascends 
on  each  side  of  the  biceps ;  the  internal  of 
these,  called  median  basilic,  runs  obliquely 
upwards  and  inwards  over  the  course  of  the 
brachial  artery,  and  joins  the  basilic  vein  above 
the  internal  condyle ;  its  lower  extremity  is 
external  to  the  brachial  artery,  which  it  crosses 
obliquely  so  as  to  get  internal  to  it  superiorly  : 


84 


REGION  -OF  THE  ELBOW. 


the  other  division  of  the  median  vein,  called 
median  cephalic,  passes  obliquely  upwards 
and  outwards,  external  to  the  prominence 
formed  by  the  biceps,  and  joins  the  cephalic  at 
an  acute  angle  above  the  external  condyle. 

The  cephalic,  the  basilic,  and  the  two  divi- 
sions of  the  median  vein  joining  them,  form  a 
figure  which  somewhat  resembles  the  Roman 
capital  letter  M. 

The  superficial  lymphatic  vessels  follow  the 
course  of  the  veins ;  those  on  the  internal  side 
are  larger  and  enter  small  ganglions,  varying 
in  number  from  two  to  five,  which  are  situated 
in  the  subcutaneous  cellular  tissue,  above  and 
in  front  of  the  internal  condyle,  where  they 
are  sometimes  seen  swollen  and  inflamed  in 
consequence  of  inflammatory  affections  of  the 
hand  or  fore- arm. 

The  subcutaneous  nerves  are  :  branches  of 
the  internal  cutaneous,  usually  three  or  four  in 
number,  the  external  cutaneous,  and  some 
twigs  from  the  radial  and  ulnar  nerves.  The 
branches  of  the  internal  cutaneous  pass  down 
to  the  fore-arm,  generally  superficial  to  the 
basilic  and  median  basilic  veins,  while  the 
external  cutaneous  lies  deeper  than  the  ce- 
phalic and  median  cephalic,  with  the  latter  of 
which  it  is  more  intimately  connected.  Some 
twigs  from  both  the  internal  and  the  external 
cutaneous  nerves  are  distributed  to  the  inte- 
guments behind  the  elbow. 

Aponeurosis. — The  aponeurosis  of  the  region 
of  the  elbow  is  continuous  with  the  brachial 
aponeurosis  above,  and  with  that  of  the  fore- 
arm inferiorly ;  it  is  strong  behind  the  elbow, 
where  it  receives  an  expansion  from  the  tendon 
of  the  triceps,  and  has  an  intimate  adhesion  to 
the  margin  of  the  olecranon :  on  each  side  it 
is  firmly  attached  to  the  condyles  of  the  hu- 
merus, sending  off  several  layers  from  its 
internal  surface,  which  form  septa  between  the 
origins  of  the  muscles  of  the  fore-arm  which 
arise  from  these  processes :  anteriorly  it  is 
spread  over  the  triangular  depression,  where 
its  strength  is  considerably  increased  by  ex- 
pansions which  it  receives  from  the  tendons  of 
the  biceps  and  the  brachials  amicus  ;  the  ex- 
pansion from  the  brachiaeus  anticus  comes 
forward  on  the  external  side  of  the  tendon  of 
the  biceps,  and  is  lost  over  the  external  mus- 
cular prominence  of  the  fore-arm  in  front  of 
the  external  condyle  ;  the  expansion  from  the 
biceps  forms  a  narrow  band  about  half  an  inch 
in  breadth  where  it  is  first  detached  from  the 
tendon  of  that  muscle ;  it  then  descends 
obliquely  to  the  inner  side  of  the  fore-arm,  on 
the  aponeurosis  of  which  it  is  lost  about  two 
inches  below  the  inner  condyle.  Superiorly 
this  expansion  crosses  over  the  brachial  artery, 
and  its  superior  margin  is  defined  by  a  lunated 
border  to  which  the  brachial  aponeurosis  is 
attached,  while  its  inferior  margin  is  con- 
founded with  the  aponeurosis  of  the  fore- 
arm. 

From  the  above  described  attachments  of 
the  tendons  of  the  biceps  and  brachiaeus  an- 
ticus to  the  aponeurosis  of  this  region,  it  fol- 
lows as  a  necessary  consequence  that  the  con- 


tractions of  these  muscles  must  have  the  effect 
of  rendering  it  more  tense. 

The  aponeurosis  of  the  arm  assumes  the 
form  of  a  very  thin  fascia  as  it  approaches  the 
superior  margin  of  the  expansion  of  the  biceps  ; 
at  this  place  it  often  appears  to  degenerate 
into  cellular  tissue  which  covers  an  oval  space 
placed  obliquely,  the  broader  extremity  of 
which  is  below,  being  bounded  by  the  expan- 
sion of  the  biceps  externally  and  inferiorly, 
and  by  a  sort  of  defined  border  terminating 
the  lower  margin  of  the  brachial  aponeurosis 
superiorly  and  internally :  in  this  oval  space 
the  brachial  artery  and  the  median  nerve  which 
lies  to  its  inner  side  are  more  thinly  covered 
than  in  any  other  part  of  their  course.  The 
aponeurosis  is  also  very  weak  on  the  external 
side  of  the  expansion  of  the  biceps,  where  it 
is  pierced  by  the  deep  branch  of  the  median 
vein,  and  by  the  external  cutaneous  nerve 
which  comes  from  beneath  the  aponeurosis  at 
this  place. 

The  brachial  artery  terminates  by  dividing 
into  the  radial  and  ulnar  arteries  in  the  tri- 
angular depression,  which  is  bounded  exter- 
nally by  the  supinator  longus  and  internally  by 
the  pronator  radii  teres. 

This  artery  enters  the  region  of  the  elbow  on 
the  internal  side  of  the  tendon  of  the  biceps 
included  in  a  common  sheath  with  its  two 
venae  comites,  one  of  which  lies  on  either  side 
of  it ;  it  lies  on  the  surface  of  the  brachiaeus 
anticus,  and,  becoming  deeper  as  it  descends, 
it  divides  into  the  radial  and  ulnar  arteries  at 
about  an  inch  below  the  level  of  the  internal 
condyle.  The  median  nerve  lies  internal  to  it, 
separated  from  it  at  first  by  cellular  tissue ; 
lower  down,  where  this  nerve  pierces  the  pro- 
nator teres,  the  external  origin  of  that  muscle 
arising  from  the  coronoid  process  is  interposed 
between  it  and  the  artery  :  the  radial  and  ulnar 
arteries,  while  still  in  this  region,  give  off  their 
recurrent  branches,  which  pass  upwards,  encir- 
cling the  condyles  of  the  humerus,  to  anasto- 
mose with  the  profundae  and  anastomotic 
branches  of  the  brachial,  as  described  in  the 
article  Brachial  Artery.  The  venae  comites 
of  the  brachial,  radial,  and  ulnar  arteries  are 
double  :  these  vessels  are  also  accompanied  by 
a  deep  set  of  lymphatics.  The  nerves  which 
traverse  this  region  beneath  the  aponeurosis 
are,  the  median  on  the  internal  side  of  the 
brachial  artery ;  the  radial,  which,  descending 
between  the  brachiaeus  anticus  and  the  supinator 
radii  longus,  then  between  the  biceps  and  ex- 
tensor carpi  radialis,  divides  into  two  branches, 
the  posterior  of  which  passes  between  the  supi- 
nator brevis  and  extensor  carpi  radialis  brevior 
to  the  muscles  on  the  back  part  of  the  fore-arm, 
while  the  anterior  branch  or  proper  radial 
nerve  descends  in  the  fore-arm  under  the  su- 
pinator radii  longus.  The  trunk  of  the  ulnar 
nerve  passes  behind  the  internal  condyle,  and 
entering  between  the  two  heads  of  the  flexor 
carpi  ulnaris  follows  that  muscle  down  the 
fore-arm. 

Development. — In  early  life  the  condyles  of 
the  humerus  are  not  so  well  marked,  nor  is 


ARTICULATION  OF  THE  ELBOW. 


65 


the  olecranon  so  prominent,  in  consequence  of 
which  extension  of  the  elbow  can  be  carried 
farther  than  in  the  adult.  At  the  same  period 
the  lesser  sigmoid  cavity  of  the  ulna  is  pro- 
portionally smaller,  and  the  annular  ligament 
of  the  radius  much  more  extensive. 

Varieties. — When  a  high  division  of  the 
brachial  artery  takes  place,  it  often  happens 
that  the  radial  artery  takes  a  superficial  course, 
sometimes  under  and  occasionally  over  the 
aponeurosis  to  its  usual  destination.  The  pos- 
sibility of  this  occurrence  should  be  constantly 
held  in  recollection  in  performing  phlebotomy 
in  this  region,  as  it  is  evident  that  the  vessel, 
when  thus  superficially  situated,  is  exposed  to 
be  wounded  by  the  lancet  of  the  operator. 

In  considering  the  relative  advantages  pre- 
sented by  each  of  the  superficial  veins  which 
may  be  selected  for  phlebotomy,  it  is  necessary 
to  remark  that  the  operation  may  be  performed 
on  any  of  the  veins  at  the  bend  of  the  arm  ; 
on  the  cephalic  and  basilic  veins  it  is  un- 
attended with  any  danger;  not  so,  however, 
when  either  the  median  basilic  or  median 
cephalic  is  the  vessel  selected.  When  bleed- 
ing in  the  median  basilic  vein  about  the  mid- 
dle of  its  course,  if  the  lancet  should  transfix 
the  vein,  there  is  danger  of  the  instrument 
wounding  the  brachial  artery,  an  accident  of 
serious  consequence ;  the  risk  of  this  accident 
is  not  so  great  when  the  vein  is  opened  near 
its  lower  part,  as  the  brachial  artery  retires 
from  it  here  towards  the  bottom  of  the  trian- 
gular depression  of  the  elbow ;  besides  the 
occasional  risk  of  wounding  the  radial  artery, 
which,  in  consequence  of  a  high  bifurcation 
of  the  brachial,  sometimes  follows  the  super- 
ficial course  already  alluded  to,  the  branches 
of  the  internal  cutaneous  nerve  may  be  wholly 
or  partially  divided  ;  in  which  latter  case  sharp 
pains  are  usually  felt  extending  along  the 
course  of  these  nerves.  Opening  the  median 
cephalic  vein  may  be  performed  without  ap- 
prehension of  injury  to  the  brachial  artery; 
the  external  cutaneous  nerve  however,  the 
trunk  of  which  lies  behind  this  vein,  may  suffer 
a  puncture,  in  consequence  of  the  lancet  being 
pushed  too  deeply,  the  consequences  follow- 
ing which  have  been  in  many  instances  a  pain- 
ful affection  extending  along  the  branches  of 
this  nerve  to  their  terminations.  In  those  un- 
fortunate cases  in  which  the  brachial  artery  is 
punctured,  should  the  wound  in  the  artery 
not  be  closed  and  united  by  properly  regulated 
pressure,  the  consequence  likely  to  ensue  may 
be  one  of  the  following:  1,  the  blood  escap- 
ing from  the  wound  in  the  artery  may  become 
diffused  through  the  cellular  membrane  of  the 
limb  extending  principally  upwards  towards 
the  axilla  along  the  sheath  of  the  vessel,  ( the 
diffused  false  aneurism ;)  2,  the  blood  which 
escapes  from  the  artery  may  be  circumscribed 
within  a  limited  space  by  the  cellular  mem- 
brane which  surrounds  it  becoming  condensed, 
(the  circumscribed  false  aneurism ;)  3,  the 
wounded  orifices  of  the  artery  and  vein  may 
remain  in  apposition,  and  adhere  to  each  other, 
allowing  the  blood   to  pass  from  the  artery 

VOL.  II. 


directly  into  the  vein,  constituting  the  affection 
called  aneurismal  varix  ;  4,  or  a  circum- 
scribed sac  may  be  formed  between  the  artery 
and  vein,  having  a  communication  with  both 
vessels,  the  varicose  aneurism. 

(J.  Hart.) 

ELBOW  (ARTICULATION  OF  THE), 
ayxcov,  cubitus  ;  Fr.  coude  ;  Germ,  elbogen  ; 
Ital.  gomito.  The  elbow  or  humero-cubital 
articulation  is  an  angular  ginglymus  formed  by 
the  inferior  articular  extremity  of  the  os  humeri 
and  the  superior  articular  extremities  of  the 
radius  and  ulna,  the  surfaces  of  which  are,  in. 
the  recent  state,  covered  with  a  cartilaginous 
incrustation,  and  kept  in  apposition  by  an  ex- 
tensive synovial  capsule,  an  anterior,  a  poste- 
rior, and  two  strong  lateral  ligaments. 

The  muscles  which  cover  this  articulation 
are,  the  brachiaeus  anticus,  the  inferior  tendon 
of  the  triceps,  and  some  of  the  muscles  of  the 
fore-arm  anteriorly,  the  triceps  and  anconasus 
posteriorly,  and  the  superior  attachments  of 
several  of  the  muscles  of  the  fore-arm  laterally. 

Bones. — The  lower  part  of  the  humerus  is 
flattened  before  and  behind,  and  curved  a  little 
forwards  :  an  obtuse  longitudinal  ridge,  on  a 
line  corresponding  to  the  lesser  tuberosity  at 
its  superior  extremity,  divides  it  into  two  slo- 
ping surfaces  anteriorly,  while  posteriorly  it 
presents  a  broad,  flat,  triangular  surface :  a 
sharp  ridge  on  each  side  terminates  below  in  a 
rough  tuberosity,  called  a  condyle  ;  the  exter- 
nal condyle  is  the  smaller  of  the  two,  and  when 
the  arm  hangs  loosely  by  the  side,  it  is  directed 
outwards  and  forwards  :  the  internal  condyle 
is  much  larger,  more  prominent,  and  directed 
inwards  and  backwards :  a  line  let  fall  per- 
pendicularly from  the  most  prominent  part  of 
the  greater  tuberosity  above  would  fall  upon 
the  external  condyle ;  the  internal  condyle 
bears  a  similar  relation  to  the  centre  of  the 
superior  articular  head  of  the  humerus.  The 
inferior  articular  surface  extends  transversely, 
below  and  between  the  condyles,  and  presents 
a  series  of  eminences  and  depressions  ;  begin- 
ning at  the  external  side,  a  small  spheroidal 
eminence,  the  eminentia  capitata  or  lesser  head, 
situated  on  the  front  of  the  external  condyle, 
directed  forwards  and  received  into  the  circular 
cavity  on  the  head  of  the  radius,  internal  to 
this  is  a  small  grooved  depression  which  lodges 
the  internal  part  of  the  border  of  that  cavity: 
the  remainder  of  this  surface  forms  a  sort  of 
pulley,  to  which  the  greater  sigmoid  cavity  of 
the  ulna  corresponds;  this,  which  is  called  the 
trochlea,  presents  a  large  depression  placed  be- 
tween two  raised  ridges  :  the  depressed  portion 
of  the  trochlea  winds  round  the  lower  extre- 
mity of  the  humerus  in  an  oblique  direction 
from  before  backwards  and  a  little  outwards, 
being  broader  behind  than  in  front ;  its  external 
border  forms  a  semicircular  ridge,  smooth  in 
front  and  sharp  behind,  the  anterior  part  of 
which  corresponds  to  the  division  between  the 
radius  and  ulna;  its  internal  margin  also  forms 
a  semicircular  ridge,  sharper  and  more  promi- 
nent than  the  external,  and  which  projects  half 


CO 


ARTICULATION  OF  THE  ELBOW. 


an  inch  below  the  internal  condyle,  having  be- 
tween it  and  this  latter  process  a  sinuosity  in 
which  the  ulnar  nerve  lies  ;  it  is  the  prominence 
of  this  ridge  which  determines  the  obliquity  in 
the  direction  of  the  humerus,  observable  when 
its  inferior  articular  extremity  is  placed  on  a 
horizontal  surface. 

Behind  and  above  the  trochlea  a  large  trian- 
gular depression  (fossa  posterior )  receives  the 
olecranon  in  extension  of  the  fore-arm  ;  a  simi- 
lar depression  of  smaller  size  (fossa  anterior) 
receives  the  coronoid  process  in  flexion  ;  these 
two  fossae  are  separated  by  a  plate  of  bone, 
often  so  thin  as  to  be  diaphanous,  and  some- 
times they  communicate  by  an  aperture,  the 
longest  diameter  of  which  is  transverse,  as  in 
the  quadrumana,  carnivora,  glires,  and  pachy- 
dermata ;  Meckel  is  of  opinion  that  the  exist- 
ence of  this  aperture  in  the  human  subject  is 
more  frequent  in  the  Negro  and  Papuas  than 
in  the  Caucasian  race  ;*  however  it  did  not 
exist  in  any  one  of  three  Negroes  and  four 
Mulattoes  which  I  dissected,  while  I  possess 
two  specimens  of  it,  and  have  seen  several 
others  which  occurred  in  Europeans  :  a  second 
small  fossa  frequently  exists  above  in  front  of 
the  eminentia  capitata,  into  which  the  head  of 
the  radius  is  received  in  complete  flexion. 

The  superior  extremity  of  the  ulna  presents 
anteriorly  a  deep  cavity,  ( the  greater  sigmoid 
cavity,)  which  is  concave  from  above  down- 
wards and  convex  in  the  transverse  direction  : 
it  is  bounded  behind  by  the  olecranon  and  in 
front  by  the  coronoid  process ;  the  surface  of 
this  cavity  is  smooth  and  covered  by  cartilage, 
with  the  exception  of  a  rough  transverse  notch 
which  extends  from  the  internal  side  nearly  the 
whole  way  across  it,  and  the  inequalities  of 
which  are  effaced  in  the  recent  state  by  a 
cushion  of  soft  adipose  tissue  :  on  the  external 
side  of  the  coronoid  process  there  is  a  small 
smooth  lateral  surface,  oval  in  shape,  ( the  lesser 
sigmoid  cavity,)  which  is  concave  from  before 
backwards ;  this  depression  is  covered  by  an 
extension  of  the  cartilage  of  the  greater  sigmoid 
cavity,  and  receives  the  internal  side  of  the 
head  of  the  radius. 

The  superior  extremity  of  the  radius  forms  a 
shallow  circular  depression  which  receives  the 
lesser  head  of  the  humerus;  this  surface  is 
covered  by  a  cartilage  which  extends  over  its 
circumference  on  a  circular  surface  applied  to 
the  lesser  sigmoid  cavity  of  the  ulna  internally, 
and  embraced  by  the  annular  ligament  in  the 
rest  of  its  extent :  the  articular  head  of  the 
radius  is  supported  on  a  cylindrical  portion, 
called  its  neck,  which  is  much  smaller  in  its 
circumference,  of  about  a  finger's  breadth  long 
and  curved  a  little  outwards,  its  junction  with 
the  shaft  of  the  bone  being  marked  internally 
by  a  rough  tuberosity,  the  tubercle  of  the  ra- 
dius, into  the  posterior  side  of  which  the  tendon 
of  the  triceps  is  inserted. 

Ligaments. — The  fibrous  ligaments  of  the 
elbow  are  four  in  number;  1st,  the  anterior 

*  Handbucli  der  menschlicherf  Anatomie,  band 

ii. 


ligament  consists  of  oblique  and  perpendicular 
fibres  arising  superiorly  from  the  front  of  the 
condyles  and  the  part  of  the  humerus  imme- 
diately above  the  two  anterior  articular  fossse, 
and  is  inserted  into  the  anterior  edge  of  the 
coronoid  process  of  the  ulna  inferiorly  ;  2d,  the 
posterior  ligament  is  less  distinct  than  the  an- 
terior, consisting  of  transverse  fibres  extending 
from  one  condyle  to  the  other,  which  become 
more  evident  when  the  elbow  is  flexed ;  3d,  the 
external  lateral  ligament  arises  from  the  ante- 
rior surface  of  the  external  condyle  by  a  thick 
cord-like  fasciculus  of  shining  silvery  fibres, 
and  spreads  out  into  a  broad  flat  expansion, 
which  is  inserted  into  the  whole  length  of  the 
annular  ligament  of  the  radius  and  into  the 
anterior  and  posterior  margins  of  the  lesser  sig- 
moid cavity  of  the  ulna;  the  tendons  of  origin 
of  the  supinator  brevis  and  extensor  muscles  of 
the  hand  are  intimately  connected  to  the  exter- 
nal surface  of  this  ligament,  but  can  be  easily 
separated  from  it  by  careful  dissection  ;  4th, 
the  internal  lateral  ligament  arises  from  the  an- 
terior surface  of  the  internal  condyle  of  the 
humerus,  and  passing  over  the  internal  side  of 
the  synovial  capsule,  divides  into  two  portions, 
an  anterior  and  a  posterior,  the  former  of  which 
is  inserted  into  the  inner  side  of  the  coronoid 
process,  and  the  latter  into  the  internal  side  of 
the  olecranon  :  this  ligament  presents  more  of 
a  flattened  form,  and  is  more  easily  separated 
from  the  tendons  of  the  muscles  which  cover  it 
than  the  external  lateral  ligament. 

The  synovial  capsule,  having  covered  the  ar- 
ticular surface  of  the  humerus,  ascends  above 
this  surface  as  high  as  an  irregular  continuous 
line,  including  the  two  anterior  articular  fossog 
in  front,  the  posterior  articular  fossa  behind, 
and  limited  by  the  bases  of  the  condyles  late- 
rally ;  at  the  level  of  this  line  the  capsule  is  re- 
flected from  the  humerus,  and  descends  on  the 
internal  surfaces  of  the  fibrous  ligaments  to  be 
expanded  over  the  articular  surfaces  of  the 
radius  and  ulna,  to  the  cartilaginous  coverings 
of  which  it  adheres  in  the  same  intimate  man- 
ner as  to  that  of  the  articular  surface  of  the 
humerus  ;  the  portion  of  it  corresponding  to 
the  radius  descends  within  the  annular  liga- 
ment, below  which  it  is  reflected  on  the  neck, 
and  thence  continued  over  the  head  of  that 
bone ;  while  it  becomes  attached  to  the  ulna  at 
the  line  which  circumscribes  the  greater  and 
lesser  sigmoid  cavities  over  the  surfaces  of 
which  it  is  extended  ;  this  capsule,  which  is 
rather  tense  where  it  lines  the  lateral  ligaments, 
is  flaccid  and  sacculated  anteriorly  and  poste- 
riorly, so  as  not  to  interfere  with  the  freedom  of 
flexion  and  extension  of  the  elbow :  below  the 
margin  of  the  annular  ligament  and  before  it 
is  attached  to  the  neck  of  the  radius,  it  forms  a 
cul-de-sac  so  loose  as  to  permit  the  rotatory 
motions  of  that  bone  to  be  executed  without 
restraint. 

Several  masses  of  adipose  cellular  tissue  are 
situated  around  the  articulation  external  to  the 
synovial  capsule,  more  especially  in  the  articu- 
lar fossae  at  the  posterior  margin  of  the  olecra- 
non :  between  the  radius  and  ulna  and  in  the 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


67 


notch  on  the  internal  side  of  the  greater  sigmoid 
cavity,  there  always  occurs  a  mass  of  this  sub- 
stance from  which  a  production  extends  over 
the  rough  groove  described  above,  dividing  the 
sigmoid  cavity  transversely. 

The  synovial  capsule  adheres  closely  to  the 
fibrous  ligaments,  except  where  masses  of  adi- 
pose tissue  are  interposed,  to  which  it  is  but 
loosely  connected. 

Motions. — The  elbow  is  a  joint  remarkable 
for  possessing  great  solidity,  which  is  partly 
owing  to  the  extent  of  its  osseous  surfaces  and 
the  manner  in  which  they  are  locked  into  each 
other,  and  partly  to  the  strong  lateral  ligaments 
and  the  muscles  which  surround  it. 

The  motions  enjoyed  by  the  elbow-joint  are 
flexion  and  extension. 

Flexion  may  vary  in  degree  so  as  to  be  com- 
plete or  incomplete :  in  complete  flexion  the 
fore-arm  is  carried  forwards  and  inwards  in  an 
oblique  direction  across  the  front  of  the  thorax, 
so  as  to  bring  the  hand  towards  the  mouth  ; 
the  direction  of  the  fore-arm  is  determined  in 
this  movement  by  the  obliquity  of  the  trochlea 
of  the  humerus  from  behind  forwards  and  in- 
wards, as  described  above,  and  influenced  by 
the  clavicle  preventing  the  falling  inwards  of 
the  shoulder;  were  it  not  for  the  support  of 
the  clavicle,  the  hand  in  this  movement,  instead 
of  being  carried  to  the  mouth,  would  be  direct- 
ed to  the  shoulder  of  the  opposite  side  :  when 
flexion  of  the  elbow  is  carried  to  its  greatest 
extent,  the  coronoid  process  and  the  head  of 
the  radius  are  received  into  the  anterior  articu- 
lar fossae  of  the  humerus,  displacing  the  adipose 
masses  from  these  cavities,  the  olecranon  is 
brought  downwards  on  the  trochlea  so  as  to  be 
placed  below  the  level  of  the  condyles  of  the 
humerus ;  the  posterior  part  of  the  synovial 
capsule,  the  posterior  ligament,  and  the  triceps 
and  anconeus  muscles  are  made  tense,  and 
applied  to  the  adipose  mass  in  the  posterior 
articular  fossa  and  to  the  posterior  part  of  the 
trochlea :  the  anterior  part  of  the  capsule  and 
the  anterior  ligament  are  relaxed,  as  are  also  the 
lateral  ligaments.  A  dislocation  is  rendered 
impossible  in  this  state  of  the  articulation, 
being  effectually  opposed  by  the  hold  which 
the  coronoid  process  has  on  the  front  of  the 
trochlea  of  the  humerus. 

In  partial  flexion  or  semiflexion,  the  several 
parts  of  the  articulation  are  differently  circum- 
stanced ;  the  coronoid  process  being  carried 
down  is  no  longer  applied  to  the  front  of  the 
humerus,  the  olecranon  is  on  a  plane  with  the 
condyles,  and  the  lateral  ligaments  are  on  the 
stretch  :  in  this  state  of  the  parts  a  powerful 
force  applied  to  the  olecranon  from  behind 
might  have  the  effect  of  displacing  the  ulna 
forwards,  were  it  not  for  the  great  mobility  of 
the  limb,  owing  to  which  a  force  thus  applied 
is  moderated  or  altogether  expended  in  increa- 
sing the  degree  of  flexion  ;  hence  a  dislocation 
of  the  ulna  forwards  on  the  humerus  is  an  acci- 
dent which  never  happens. 

In  extension,  the  olecranon,  ascending  above 
the  level  of  the  condyles,  is  received  into  the 
posterior  articular  fossa,  displacing  the  adipose 
substance  which  previously  occupied  that  fossa, 


the  radius  is  brought  back  on  the  lesser  head 
of  the  humerus,  over  the  anterior  part  of  which 
and  of  the  trochlea  the  capsule  and  the  anterior 
ligament  are  stretched;  the  lateral  ligaments, 
the  tendon  of  the  triceps,  and  the  brachials 
anticus  are  also  in  a  state  of  tension  :  the  pos- 
terior part  of  the  capsule  and  the  posterior 
ligament  are  necessarily  relaxed.  It  is  when 
the  elbow  is  in  such  a  state  of  extension  as 
here  described  that  a  dislocation  of  the  fore-arm 
backwards  usually  occurs  in  consequence  of  a 
fall  on  the  hand ;  the  force  producing  the  dis- 
location in  this  case  operates  in  the  following 
way,  the  fore-arm  serving  as  a  fixed  point,  the 
humerus  becomes  a  lever  of  the  first  order,  the 
fulcrum  of  which  is  the  point  of  the  olecranon 
applied  to  the  posterior  side  of  its  lower  extre- 
mity, the  power  is  represented  by  the  weight 
of  the  trunk  of  the  body  applied  to  its  superior 
extremity  in  front,  and  acting  with  a  force  pro- 
portioned to  its  remoteness  from  the  point  of 
resistance  formed  by  the  ligaments  and  muscles 
which  are  found  in  a  state  of  tension  in  front ; 
when  this  force  is  such  as  to  overcome  the  re- 
sistance, the  ligaments  in  front  are  ruptured, 
the  lower  extremity  of  the  humerus  is  then 
driven  downwards  in  front  of  the  bones  of  the 
fore-arm,  the  upper  extremities  of  which  are 
forced  upwards  behind  the  humerus,  so  that 
the  coronoid  process  comes  to  occupy  the  nor- 
mal situation  of  the  olecranon  in  the  posterior 
articular  fossa. 

Lateral  motion.  —  Anatomists  have  been 
divided  in  opinion  as  to  the  possibility  of  any 
lateral  motion  being  performed  by  the  ulna  on 
the  humerus.  Albinus,  Boyer,  Beclard,  Cru- 
veilhier,  and  others,  have  denied  the  occurrence 
of  it;  Monro  and  Bichat,  however,  have  dis- 
tinctly noticed  it :  they  consider  that  this  mo- 
tion is  possible  only  in  the  semifixed  state  of 
the  elbow,  when  the  lateral  ligaments  are  most 
relaxed  :  in  complete  flexion,  as  well  as  in  ex- 
tension, the  tense  state  of  these  ligaments  effec- 
tually opposes  any  such  movement.  In  my 
opinion  it  is  easy  to  satisfy  one's  self  as  to  the 
occurrence  of  this  motion  ;  it  consists  of  a  slight 
degree  of  rolling  of  the  middle  prominent  part 
of  the  greater  sigmoid  cavity  in  the  fossa  of  the 
trochlea,  produced  by  those  fibres  of  the  lower 
part  of  the  triceps  which  extend  from  the  con- 
dyle on  each  side  to  the  olecranon,  and  by  the 
action  of  the  anconeus  externally, 

(J.  Hart.) 

ELBOW-JOINT,  ABNORMAL  CON- 
DITION OF.— Placed  in  the  middle  of  the 
long  lever  which  the  upper  extremity  repre- 
sents, the  elbow-joint  is  of  necessity  exposed 
to  numerous  accidents,  the  most  remarkable  of 
which  are  fractures  and  luxations.  These,  re- 
duced or  unreduced,  produce  immediate  and 
remote  effects,  to  which  it  is  our  business  in 
this  place  to  advert.  Congenital  malforma- 
tions sometimes,  though  very  rarely,  are  to  be 
met  with  affecting  this  articulation,  and  require 
some  brief  consideration. 

The  several  structures  too,  which  enter  into 
the  composition  of  the  elbow-joint,  are  each 
and  all  occasionally  affected   by  acute  and 

f  2 


08 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


chronic  inflammations,  the  consequences  of 
which  we  cannot  omit  to  notice,  and  many  of 
these  have  their  reputed  source  either  in  struma 
or  syphilis,  while  others  are  attributed  to  an  ar- 
thritic or  to  a  rheumatic  diathesis. 

I.  -Accident. — Fractures. — Fractures  of  the 
bones  of  the  elbow-joint  may  be  classed  as 
to  their  situation  and  direction  :  first,  as  they 
affect  the  lower  extremity  of  the  humerus  ;  and, 
secondly,  as  they  engage  the  upper  extremities 
of  the  bones  of  the  fore-arm. 

1.  Simple  fractures  of  the  humerus  near 
the  elbow-joint  may  be  transverse  or  oblique. 
When  this  bone  is  fractured  transversely  at  its 
lower  part  immediately  above  its  condyles,  or 
in  young  subjects  through  its  lower  epiphysis, 
in  either  case  the  olecranon  process  is  pulled 
backwards  and  upwards  by  the  triceps,  while 
the  part  of  the  humerus  superior  to  the  fracture, 
that  is,  almost  the  whole  of  the  bone,  is  carried 
forwards,  and  forms  such  a  projection  below  as 
much  resembles  a  luxation  forwards  of  the  true 
articular  extremity  of  the  bone  ;  the  prominence 
in  front  is  also  considerably  increased  by  the  in- 
clination forwards  of  the  upper  extremity  of  the 
lower  short  fragment,  which  is  pulled  in  this 
direction  by  the  supinators  and  pronators  taking 
their  fixed  point  below.  The  prominence  for- 
wards, fori  led  by  the  angle  of  contact  between 
the  upper  and  lower  fragments  of  the  humerus, 
is  covered  in  front  by  the  brachialis  anticus 
and  biceps;  and  there  is  a  projection  behind 
formed  by  the  olecranon  process  equally  well 
marked  ;  so  that,  in  comparing  the  posterior 
aspects  of  the  two  articulations,  we  see  the  ole- 
cranon process  at  the  affected  side  exceed  by  its 
projection  backwards  that  of  the  uninjured  arm 
an  inch  or  more  :  when  to  all  this  we  add  the 
observation  that  the  antero-posterior  diameter  of 
the  arm  is  evidently  augmented,  we  have  here 
many  of  the  signs  which  might  lead  one  to  sus- 
pect the  existence  of  the  luxation  of  the  bones  of 
the  fore-arm  backwards.  There  is  this  differ- 
ence however,  namely,  that  in  fracture  a  crepitus 
can  be  felt,  and  the  deformity  is  not  accompa- 
nied with  any  changes  of  the  normal  relations 
existing  between  the  olecranon  and  the  con- 
dyles. 

Oblique  fractures  near  the  elbow-joint  are 
usually  prolonged  into  the  articulation,  and 
may  be  either  external  or  internal.  The  frac- 
ture may  traverse  in  an  oblique  line  from 
without  inwards,  and  from  above  downwards ; 
and  then  the  external  condyle  and  capitulum 
of  the  humerus  will  be  detached  from  the  shaft 
of  that  bone,  and  will  constitute  the  external 
or  inferior  fragment ;  or  the  fracture  may  take 
place  obliquely  from  above  downwards,  and 
from  within  outwards,  so  as  to  comprehend 
the  trochlea  of  the  humerus  and  internal  con- 
dyle in  the  inner  fragment.  In  the  first  case, 
or  external  fracture,  the  posterior  muscles  of 
the  fore-arm  will  have  a  tendency  to  pull 
the  condyle  downwards  and  backwards  ;  and 
in  the  second,  the  internal  fragment  with  the 
trochlea  will  be  drawn  downwards  and  for- 
wards by  the  pronator  muscles. 

Oblique  fractures,  extending  into  the  elbow- 
joint,  detaching  the  external  condyle  of  the  os 


humeri,  maybe  detected  by  the  following  sym- 
ptoms. There  is  considerable  swelling  and 
pain  upon  pressure  on  the  external  condyle  : 
and  the  motions  of  the  elbow-joint,  both  of  ex- 
tension and  flexion,  are  performed  with  pain; 
but  the  principal  diagnostic  sign  is  the  crepitus 
produced  by  communicating  a  rotatory  motion 
to  the  fore-arm.  If  the  portion  of  the  frac- 
tured condyle  be  large,  it  is  drawn  a  little 
backwards,  and  it  carries  the  radius  with  it ; 
but  if  the  portion  be  small,  this  circumstance 
does  not  occur ;  if  the  fracture  of  the  external 
condyle  take  place  immediately  above  it  and 
within  the  synovial  sac,  it  is  stated  by  Sir  A. 
Cooper  that  no  union  will  take  place  except 
by  means  of  ligament.*  The  oblique  fracture 
of  the  external  condyle  is  frequently  met  with 
in  children  ;  a  fall  on  the  hand  forwards  may 
cause  it,  the  impulse  being  transmitted  along 
the  radius  to  the  capitulum  and  outer  condyle 
of  the  humerus.  The  connexion  of  the  radius 
with  the  ulna  at  this  period  of  life  is  so  loose 
that  no  resistance  is  afforded  to  the  forcible 
ascent  of  the  radius  when  a  sudden  fall  for- 
wards on  the  palm  of  the  hand  occurs :  and 
hence  in  the  young  subject  particularly  an 
oblique  fracture  of  the  outer  condyle  of  the 
humerus  can  readily  happen  :  at  a  late  period 
of  life,  the  connexions  between  the  bones  of 
the  fore-arm  are  so  strong  and  unyielding,  that 
from  a  similar  fall  forwards  on  the  hand,  it  is 
the  lower  extremity  of  the  radius  which  would 
be  obliquely  fractured. 

There  is  at  this  moment  in  the  Richmond 
Hospital  a  young  woman  who  met  with  this 
oblique  fracture  of  the  external  condyle  of  the 
humerus  near  the  elbow,  when  she  was  only 
five  years  of  age.  The  outer  condyle  and 
capitulum  of  the  humerus  were  detached  ob- 
liquely from  the  shaft  of  the  bone  and  thrown 
backwards,  carrying  with  them  the  head  and 
upper  extremity  of  the  radius  ;  she  now  has 
very  good  use  of  her  arm,  but  in  consequence 
of  the  accident  much  deformity  exists,  parti- 
cularly when  she  extends  the  fore-arm.  The 
obtuse  angle  salient  internally,  which  the  fore- 
arm forms  with  the  arm  in  the  natural  state 
when  it  is  fully  extended,  and  the  hand  supi- 
nated,  does  not  exist.  On  the  contrary,  in  this 
case  the  salient  angle  is  external,  and  corres- 
ponds to  the  outer  condyle  and  head  of  the 
radius,  and  the  retiring  angle  is  placed  inter- 
nally.   (See  Jig.  40.) 

The  internal  condyle  of  the  humerus  is  fre- 
quently broken  obliquely  from  the  body  of  the 
bone,  and  the  symptoms  by  which  the  accident 
is  known  are  the  following :  when  the  fore-arm 
is  extended  on  the  arm,  the  ulna  projects  be- 
hind the  humerus;  the  lower  end  of  the  hume- 
rus, too,  advances  on  the  ulna,  so  that  it  can 
be  easily  felt  on  the  anterior  part  of  the  joint ; 
on  flexing  the  fore-arm  on  the  arm,  the  ulna 
resumes  its  usual  position ;  by  grasping  the 
condyles  and  bending  and  extending  the  fore- 
arm, a  crepitus  is  perceived  at  the  internal  con- 
dyle :  this  accident  usually  occurs  in  youth, 

*  See  plate  xxvi.  fig.  1,  of  Sir  A.  Cooper's  work 
on  Fractures  and  Dislocations. 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


69 


Fig.  40. 


Fracture  and  retraction  of  the  outer  condyle  of  the  humerus. 


although  it  may  be  seen  in  those  advanced  in 
life.  It  is  an  injury  very  likely  to  be  mis- 
taken for  a  dislocation. 

2.  Fractures  which  engage  the  upper  extre- 
mity of  the  bones  of  the  fore-arm  are  chiefly 
confined  to  the  ulna,  for  the  radius  very  seldom 
suffers.  Sometimes  the  olecranon  process  at 
the  ulna  is  broken  off,  and  occasionally  a  frac- 
ture of  the  coronoid  process  occurs,  the  con- 
sequences of  which  last  accident  are  sometimes 
very  serious.  Sir  A.  Cooper  gives  us  the  fol- 
lowing history:  "A  gentleman  came  to  London 
for  the  opinion  of  different  surgeons  upon  an 
injury  he  had  received  in  his  elbow.  lie  had 
fallen  on  his  hand  whilst  in  the  act  of  running, 
and  on  rising  he  found  his  elbow  incapable  of 
being  bent,  nor  could  he  entirely  extend  it ; 
he  applied  to  his  surgeon  in  the  country,  who 
upon  examination  found  that  the  ulna  pro- 
jected backwards  when  the  arm  was  ex- 
tended, but  it  was  without  much  difficulty  drawn 
forwards  and  bent,  and  the  deformity  was  then 
removed.  It  was  concluded  that  the  coronoid 
process  was  detached  from  the  ulna,  and  that 
thus  during  extension  the  ulna  slip]  ed  back 
behind  the  inner  condyle  of  the  humerus." 

A  preparation  of  an  accident,  supposed  to 
be  similar,  is  preserved  in  the  Museum  of  St. 
Thomas's  Hospital;  the  coronoid  process,  which 
had  been  broken  off  within  the  joint,  had  united 
by  ligament  only,  so  as  to  move  readily  upon 
the  ulna,  and  thus  alter  the  sigmoid  cavity  of 
the  ulna  so  much  as  to  allow  in  extension  that 
bone  to  glide  backwards  upon  the  condyles  of 
the  humerus. 

Fracture  of  the  olecranon. — This  process  of 
the  ulna  is  not  unfrequently  broken  off,  and 
the  accident  is  attended  by  symptoms  which 
render  the  injury  so  evident  that  the  nature  of 
the  case  can  hardly  be  mistaken.  Pain  is  felt 
at  the  back  of  the  elbow,  and  a  soft  swelling 
is  soon  produced  there,  through  which  the 
surgeon's  finger  readily  sinks  into  the  joint ; 
the  olecranon  can  be  felt  in  a  detached  piece 
elevated  sometimes  to  half  an  inch  and  some- 
times to  two  inches  above  the  portion  of  the 
ulna  from  which  it  has  been  broken.  This 
elevated  portion  of  bone  moves  readily  from 
side  to  side,  but  it  is  with  great  difficulty 
drawn  downwards  ;  if  the  arm  be  bent,  the 
separation  between  the  ulna  and  olecranon  be- 
comes much  greater. 

The  patient  has  scarcely  any  power  to  extend 
the  fore-arm,  and  the  attempt  produces  very 
considerable  pain,  but  he  bends  it  with  facility, 


and  if  the  limb  be  left  undisturbed  it  is  prone 
to  remain  in  the  semiflexed  position.  For  se- 
veral days  after  the  injury  has  been  sustained, 
much  swelling  of  the  elbow  is  produced,  there 
is  an  appearance  of  ecchymosis  to  a  consider- 
able extent,  and  an  effusion  of  fluid  into  the 
joint  ensues;  but  the  extent  to  which  these 
symptoms  proceed  depends  upon  the  violence 
which  produced  the  accident.  The  rotation  of 
the  radius  upon  the  ulna  is  still  preserved;  no 
crepitus  is  felt  unless  the  separation  of  the  bone 
is  extremely  slight.  Fractures  of  the  upper 
extremity  of  the  ulna  are  sometimes  very  com- 
plicated. Thus  Mr.  Samuel  Cooper  informs  us 
that  there  is  a  preparation  in  the  Museum  of  the 
London  University,  illustrating  a  case  in  which 
the  ulna  is  broken  at  the  elbow,  the  posterior 
fragment  being  displaced  backwards  by  the 
action  of  the  triceps  ;  the  coronoid  process  is 
broken  off ;  the  upper  head  of  the  radius  is 
also  dislocated  from  the  lesser  sigmoid  cavity 
of  the  ulna,  and  drawn  upwards  by  the  action 
of  the  biceps. 

Luxations. — The  bones  of  tho  fore-arm  are 
liable  to  a  great  variety  of  luxations  at  the 
elbow-joint ;  the  following  arrangement  will  pro- 
bably be  found  to  comprehend  most  of  those 
accidents  as  yet  known  and  described. 

1.  Luxations  of  both  bones  backwards;  2. 
Luxations  of  both  bones  laterally,  complete 
and  incomplete  ;  3.  Luxations  of  both  bones 
laterally  and  posteriorly  ;  4.  Luxation  of  the 
ulna  alone  backwards;  5.  Luxation  of  the 
radius  alone  forward  ;  6.  Luxation  of  the  ra- 
dius externally  and  superiorly ;  7.  Complete 
luxation  of  the  radius  backwards  ;  8.  Sub-lux- 
ation of  the  radius  backward  ;  9.  Congenital 
luxation  of  the  radius. 

1.  Luxation  of  both  bones  of  the  fore-arm 
backwards. — This  luxation  is  the  most  frequent 
of  all  those  to  which  the  elbow-joint  is  liable; 
it  is  usually  produced  by  a  fall  on  the  palm  of 
the  hand,  the  fore-arm  being  at  the  time  ex- 
tended on  the  arm,  and  carried  forwards,  as 
when  a  person  falling  forwards  puts  out  his 
hand  to  save  himself. 

The  patient  suffers  at  the  moment  of  the  acci- 
dent an  acute  pain  in  the  elbow-joint,  and  is  often 
conscious  of  something  having  given  way  in  the 
joint.  The  fore-arm  inclines  to  a  state  of  supina- 
tion (Jig.  41);  the  whole  extremity  is  manifestly 
shortened  ;  the  olecranon  process  rises  very 
much  above  the  level  of  the  tuberosities;  or,  to 
speak  more  correctly,  with  reference  to  the  po- 
sition of  the  limb,  which  is  always  presented  to 


70 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


Fig.  41. 


Luxation  of  both  bones  backwards. 


us  for  examination  more  or  less  flexed,  this 
process  is  placed  much  behind  and  somewhat 
below  the  plane  of  the  condyles  of  the  humerus. 
The  tendon  of  the  triceps  carried  back  with  the 
olecranon  stands  out  in  relief,  as  the  tendo 
Achillis  does  from  the  malleoli.  This  part  of 
the  triceps  thus  standing  out  can  be  seized 
through  the  integuments  by  the  fingers,  and  we 
perceive  in  front  an  interval  between  it  and  the 
back  part  of  the  humerus.  Anteriorly,  in  the 
fold  of  the  arm,  through  the  thickness  of  the 
soft  parts,  we  can  feel  a  hard  tumour,  situated 
obliquely  from  without  inwards  and  back- 
wards, formed  by  the  lower  articular  extremity 
of  the  humerus.  The  rounded  head  of  the 
radius  can  be  seen  prominent  below  the  exter- 
nal condyle,  and  we  can  occasionally  even  sink 
the  end  of  the  thumb  into  the  hollow  of  its 
cup-like  extremity,  and  if  now  a  movement  of 
pronation  and  supination  be  communicated  to 
it,  the  nature  of  the  case  becomes  very  evi- 
dent. 

The  patient  himself  feels  the  arm  powerless, 
and  we  find  we  can  communicate  to  it  but 
little  motion.  When  we  make  the  attempt  to 
rotate  or  flex  the  arm  on  the  fore-arm,  we  find 
our  efforts  resisted,  and  that  we  give  the  patient 
pain  ;  a  little  extension  of  the  elbow-joint  is 


allowed ;  and  we  have  invariably  found  that  a 
lateral  movement  of  abduction  and  adduction 
could  be  given  to  the  fore-arm,  motions  this 
joint  does  not  enjoy  in  the  natural  state,  but 
which  we  can  account  for  being  now  permitted, 
when  we  recollect  the  complete  laceration  the 
lateral  ligaments  must  suffer  in  this  injury. 

The  transverse  fracture  of  the  lower  extremity 
of  the  humerus,  or  a  forcible  separation  of  its 
lower  epiphysis,  are  accidents  most  liable  to 
be  confounded  with  luxation  of  both  bones 
backwards;  but  although  the  elbow  projects 
much  backwards,  and  there  is  a  marked 
prominence  in  front,  still  the  relative  position 
of  the  condyles  of  the  humerus  and  the  olecra- 
non process  is  not  altered  in  the  fracture,  as  they 
have  already  been  described  to  be,  in  the  lux- 
ation. Add  to  this,  that  in  the  fracture  the  sur- 
geon can  flex  the  patient's  fore-arm  on  his  arm, 
a  movement  which,  in  the  luxation,  the  patient 
can  neither  himself  fully  perform,  nor  can  it  be 
communicated. 

In  the  case  of  the  transverse  fracture  also, 
notwithstanding  the  apparent  similitude  at  first 
with  the  luxation,  when  a  steady  extension  is 
made  by  pulling  the  hand  forwards,  while  the 
arm  is  fixed,  all  the  marks  of  luxation  disap- 
pear, to  return  again  very  shortly,  when  the 
extending  force  is  relaxed.  In  fracture,  too,  a 
characteristic  crepitus  may  be  felt  just  above 
the  elbow-joint,  by  rotating  the  fore-arm  on  the 
humerus.  It  is  very  true  that,  in  some  cases 
of  luxation,  the  dislocated  bones  are  very  rea- 
dily restored  to  their  place,  and  on  the  other 
hand,  that  a  transverse  fracture  of  the  humerus 
may,  after  it  is  reduced,  remain  so  for  a  little 
time,  and  thus  we  may  perhaps  account  for  the 
fact,  that  these  accidents  have  been  confounded 
with  each  other,  and  the  mistake  is  a  serious 
one.  To  guard  against  error  in  our  diagnosis, 
it  would  be  well,  after  the  bones  have  been  re- 
duced, to  try  the  experiment  of  pushing  the 
fore-arm  backwards,  while  the  arm  is  steadily 
pressed  forwards ;  if  the  accident  has  been  a 
luxation,  no  change  occurs,  but  if  there  has 
been  a  transverse  fracture  of  the  humerus,  or 
of  the  coronoid  process  of  the  ulna,  all  appear- 
ances which  erroneously  induced  a  suspicion 
that  the  accident  was  one  of  luxation,  are  re- 
newed, but  not  so  the  error  of  attributing  these 
appearances  to  a  luxation,  for  now  the  exist- 
ence of  a  fracture  can  no  longer  be  doubted. 
Lastly,  after  the  bones,  in  a  case  of  luxation, 
are  apparently  restored,  it  will  be  prudent  to 
examine  the  head  of  the  radius,  and  it  will  be 
right  to  be  satisfied  that  this  bone  has  also  been 
replaced  as  well  as  the  ulna,  for,  in  the  luxa- 
tion of  both  bones  backwards,  the  connexion  of 
the  radius  with  the  ulna  by  means  of  the  coronary 
and  oblique  ligaments,  may  have  suffered,  and 
under  such  circumstances,  if  care  be  not  taken, 
the  restoration  of  the  radius  to  the  lesser  sig- 
moid cavity  of  the  ulna  and  capitulum  of  the 
humerus  may  have  been  forgotten,  as  we  have 
known  to  have  happened  in  one  instance. 

When  the  luxation  of  both  bones  backwards 
is  simple,  and  by  mistake  or  neglect  has  been 
left  unreduced,  the  case  soon  becomes  irreme- 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


71 


diable  ;  the  patient  for  ever  loses  the  power  of 
fully  flexing  the  fore-arm,  and  the  muscles  of 
the  arm  become  more  or  less  atrophied ;  the 
powers  of  pronation  and  supination  also  become 
impaired,  but  extension  of  the  elbow-joint  can 
be  performed. 

Sir  A.  Cooper  had  an  opportunity  of  dissect- 
ing a  compound  luxation  of  the  elbow-joint,  in 
which  the  radius  and  ulna  were  thrown  back- 
wards, and  the  specimen  is  preserved  in  the 
Museum  of  St.  Thomas's  Hospital,  and  a  re- 
presentation given  in  his  work  on  dislocations : 
see  plate  xxiii.  fig.  2.  The  coronoid  process 
of  the  ulna  was  thrown  into  the  posterior  fossa 
of  the  os  humeri,  and  the  olecranon  projected 
at  the  back  part  of  the  elbow,  above  its  natura  1 
situation,  an  inch  and  a  half.  The  radius  was 
placed  behind  the  external  condyle  of  the  os 
humeri,  and  the  humerus  was  thrown  forwards 
on  the  anterior  part  of  the  fore-arm,  where  it 
formed  a  large  projection.  The  capsular  liga- 
ment was  torn  through  anteriorly  to  a  great  ex- 
tent;  the  coronary  ligament  remained  entire. 
The  biceps  muscle  was  slightly  put  on  the 
stretch  by  the  radius  receding,  but  the  brachia- 
lis  anticus  was  excessively  stretched  by  the 
altered  position  of  the  coronoid  process  of  the 
ulna. 

This  was  a  recent  case ;  but  it  would  ap- 
pear from  the  dissections  which  have  been 
made  of  cases  which  had  been  left  for  a  long 
time  unreduced,  that  a  new  bony  cavity  had 
been  made  on  the  front  of  the  coronoid  process 
of  the  ulna,  while  the  brachialis  anticus  be- 
came the  seat  of  ossific  depositions.  An  in- 
teresting case  of  this  kind  is  recorded  by  Cru- 
veilhier,  and  figured  by  him  in  his  Anat.  Pathol, 
plate  iv.  fig.  1.  Beclard  also  met  with  a  simi- 
lar case  in  dissection. 

2.  Lateral  dislocation  of  the  bones  of  the  fore- 
arm.— Lateral  dislocations  of  the  elbow-joint  are 
rare,  and  this  circumstance  is  owing  to  the  great 
transverse  extent  of  the  articular  surfaces,  to  the 
inequalities  which  the  corresponding  surface 
of  the  humerus  presents  in  the  transverse  di- 
rection, to  the  strength  of  the  lateral  liga- 
ments, and  the  attachment  to  them  of  the  tendons 
of  those  superficial  muscles  which  pass  to  the 
anterior  and  posterior  part  of  the  fore-arm, 
which  tendons  almost  identify  themselves  with 
the  laleral  ligaments,  and  must  considerably 
strengthen  and  support  the  joint  laterally. 
Again,  the  force  which  would  have  a  tendency 
to  luxate  the  bones  laterally  can  very  rarely  be 
directed  in  such  a  manner  as  to  produce  the 
luxation  we  are  now  considering,  nor  are  the 
muscles  ever  so  directed  as  to  produce  them. 

We  find  in  authors  circumstantial  accounts 
of  the  symptoms  of  the  complete  luxation 
outwards  and  also  of  the  complete  luxation 
inwards  ;  but  we  have  not  had  any  opportuni- 
ties ourselves  of  witnessing  these  complete  luxa- 
tions as  the  immediate  result  of  accidents. 
Indeed  we  can  scarcely  conceive  any  complete 
luxation  outwards  to  correspond  exactly  to  the 
description  given ;  as  we  imagine  that  when- 
ever the  bones  of  the  fore-arm  are  completely 
thrown  outwards,  these  bones  must  be  drawn 


Fig.  42. 


Luxation  outwards  of  both  bones  of  the  fore-arm, 
consecutive  to  caries  of  the  trochlea  and  great 
sigmoid  canity  of  the  ulna. 

immediately  upward  along  the  outer  side 
of  the  arm.  We  can  conceive  it  possible, 
however,  that  the  bones  of  the  fore-arm  may 
be  completely  dislocated  inwards  from  the 
trochlea  of  the  humerus,  and  still  be  restrained 
from  yielding  to  those  forces  which  would  draw 
them  upwards  and  inwards,  by  the  great  pro- 
jection inwards  of  the  internal  condyle  of  the 
humerus,  which  we  know  is  so  much  more 
prominent  than  the  external.  We  could  scarcely 
mistake  the  case  of  complete  lateral  luxation 
of  the  fore-arm,  whether  it  was  inwards  or 
outwards. 

In  the  incomplete  lateral  luxations  of  the 
bones  of  the  fore-arm  at  the  elbow-joint,  the 
articular  surfaces  of  the  bones  are  still  in  con- 
nexion, but  the  points  of  contact  of  their 
naturally  corresponding  surfaces  are  altered 
more  or  less  as  to  their  relative  positions  to 
each  other.  In  these  luxations  the  bones  of 
the  fore-arm  may  be  thrown  partially  outwards 
or  partially  inwards.  In  the  luxation  outwards, 
the  cavity  of  the  superior  extremity  of  the 
radius  abandons  the  lesser  head  of  the  humerus, 
and  its  cup-like  extremity  may  be  felt  beneath 
the  skin,  while  the  great  sigmoid  cavity  of  the 
ulna  corresponds  to  the  capitulum  of  the 
humerus  from  which  the  radius  has  been  dis- 
placed. As  to  the  anatomy  of  the  parts  under 
such  circumstances,  the  ligaments  must  be  all 
torn,  the  biceps  and  triceps  muscles  must  be 
pulled  outwards  in  the  direction  of  the  bones 
of  the  fore-arm,  into  which  they  are  inserted, 
the  supinator  brevis  muscle  cannot  escape  lace- 
ration, and  the  musculo-spiral  nerve  must  be 
more  or  less  stretched.  There  must  be  danger 
of  such  a  luxation  being  rendered  complete  or 
even  compound. 

One  of  the  most  remarkable  of  the  external 
signs  of  this  injury  is  an  increase  of  breadth  of 
the  fore-arm  in  the  line  of  the  articulation.  There 
is  a  considerable  projection  seen  at  the  outer 
side  of  the  arm  formed  by  the  head  of  the  radius, 
and  an  angular  depression  immediately  above 
this.    On  the  inner  side  of  the  arm  we  see  the 


72 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


prominence  formed  by  the  inner  condyle  of  the 
humerus,  and  its  lower  extremity.  The  fore-arm 
is  flexed,  and  the  patient  feels  it  impossible  to 
move  the  joint.  The  deviation  and  curved  direc- 
tion outwards  given  to  the  biceps  and  triceps, 
and  approximation  of  the  olecranon  to  the 
outer  condyle  of  the  humerus,  all  taken  toge- 
ther sufficiently  characterize  this  rare  accident. 

In  the  incomplete  luxation  inwards,  the 
cavity  of  the  superior  extremity  of  the  radius, 
in  abandoning  the  small  head  of  the  humerus, 
may  be  carried  more  or  less  inwards,  and  be 
placed  under  the  internal  border  of  the  articu- 
lar pulley  or  trochlea  of  this  bone,  while  the 
inner  edge  of  the  great  sigmoid  cavity  of  the 
ulna  and  olecranon  process  must  project  in- 
wards beneath  the  inner  condyle  of  the  humerus. 
The  ligaments  must  be  all  torn  as  well  as  some 
of  the  muscles  arising  from  the  internal  con- 
dyle of  the  humerus,  the  biceps  and  triceps 
are  turned  from  their  usual  direction  and  are 
curved  inwards,  and  the  ulnar  nerve  must  be 
more  or  less  stretched.  The  external  signs  of 
incomplete  luxation  inwards  are  what  the 
anatomy  of  the  parts  above  described  would 
lead  us  to  expect;  there  is  a  remarkable  increase 
of  breadth  across  the  line  of  the  joint,  perma- 
nent flexion  of  the  fore-arm,  and  a  powerless 
condition  of  the  limb,  all  which  were  noticed 
m  the  former  case.  We  must  add  to  these  a 
remarkable  projection  below  and  internal  to 
the  inner  condyle  of  the  humerus,  formed  by 
the  internal  edge  of  the  great  sigmoid  cavity 
of  the  ulna.  Our  attention  is  also  attracted  by 
the  approximation  of  the  olecranon  process 
and  inner  condyle  of  the  humerus  to  each  other, 
and  the  distance  Of  the  olecranon  from  the 
outer  condyle  of  the  humerus,  which  forms  a 
remarkable  projection  externally. 

3.  Under  the  head  of  lateral  luxations  of 
the  elbow-joint,  Sir  A.  Cooper  has  described 
accidents  which  might  perhaps  be  more  cor- 
rectly designated- — a,  complete  luxation  of  the 
bones  of  the  fore-arm  at  the  elbow  backwards 
and  outwards ;  b,  complete  luxation  of  the 
bones  of  the  fore-arm  at  the  elbow  backwards 
and  inwards. 

a.  Luxation  of  the  bones  of  the  fore-arm 
backwards  and  outwards. — In  this  case  the 
ulna,  instead  of  being  thrown  into  the  posterior 
fossa  of  the  os  humeri,  has  its  coronoid  process 
situated  on  the  back  part  of  the  external  con- 
dyle of  the  humerus.  The  projection  of  the 
ulna  backwards  is  greater  in  this  than  in  the 
former  luxation,  and  the  radius  forms  a  pro- 
tuberance behind  and  on  the  outer  side  of  the 
os  humeri,  so  as  to  produce  a  depression  above 
it.  The  rotation  of  the  head  of  the  radius  can 
be  distinctly  felt  by  rolling  the  hand. 

b.  Luxation  of  the  bones  of  the  fore-arm 
backwards  and  inwards. — Sometimes  the  ulna 
is  thrown  on  the  internal  condyle  of  the  os 
humeri,  but  it  still  projects  posteriorly,  as  in 
the  external  dislocation,  and  then  the  head  of 
the  radius  is  placed  in  the  posterior  fossa  of 
the  humerus.  The  external  condyle  of  the 
humerus  in  this  case  projects  very  much  out- 
wards, and  the  usual  prominence  of  the  inter- 


nal condyle  is  lost.  The  olecranon  process 
approaches  nearer  than  natural  to  the  middle 
line  of  the  body,  and  is  pointed  inwards,  being 
thrown  more  posteriorly  than  in  any  other  lux- 
ation. 

4.  Luxation  of  the  ulna  alone  directly  back- 
wards.— The  ulna  is  sometimes  thrown  back 
upon  the  os  humeri,  without  being  followed 
by  the  radius.  The  appearance  of  the  limb  is 
much  deformed  by  the  contortion  inwards  of 
the  fore-arm  and  hand ;  the  olecranon  projects, 
and  can  be  felt  behind  the  os  humeri.  Exten- 
sion of  the  arm  is  impracticable  but  by  force, 
which  will  reduce  the  luxation,  and  it  cannot 
be  bent  to  more  than  a  right  angle.  It  is  an 
accident  somewhat  difficult  to  detect,  but  its 
distinguishing  marks  are  the  projection  of  the 
ulna,  and  the  twist  of  the  fore-arm  inwards. 
A  specimen  of  this  accident  is  preserved  in  the 
Museum  of  St.  Thomas's  Hospital ;  the  luxa- 
tion had  existed  for  a  length  of  time.  The 
coronoid  process  of  the  ulna  was  thrown  into 
the  posterior  fossa  of  the  humerus,  and  the 
olecranon  was  found  projecting  behind  the 
humerus  much  beyond  its  usual  situation. 
The  radius  rested  upon  the  external  condyle, 
and  had  formed  a  small  socket  for  its  head,  in 
which  it  was  able  to  roll.*  The  coronary  and 
oblique  ligaments  had  been  torn  through,  and 
also  a  small  part  of  the  interosseous  ligament. 
The  brachialis  anticus  was  stretched  round  the 
trochlea  of  the  humerus,  and  the  triceps  had 
been  carried  backwards  with  the  olecranon. 

5.  Luxations  of  the  upper  extremity  of  the 
radius  from  the  humerus  and  ulna. — When  we 
look  into  the  best  books  we  possess  for  infor- 
mation on  this  subject,  we  must  be  struck  with 
the  remarkable  discrepancy  of  the  opinions  we 
find  expressed  by  the  authors.  Thus,  upon 
the  subject  of  luxation  forwards  of  the  radius, 
we  find  the  celebrated  Boyer  stating  that  he 
doubts  such  a  luxation  can  occur  without  being 
complicated  with  a  fracture.  Sanson  states  that 
this  luxation  forwards  has  never  been  observed, 
and  moreover  advances  what  he  considers  as 
anatomical  and  physiological  explanations,  to 
show  the  impossibility  of  such  an  occurrence. 
Sir  A.  Cooper,  on  the  contrary,  gives  six 
examples  of  the  luxation  of  the  upper  extre- 
mity of  the  radius  forwards.  The  French 
writers  state  of  the  luxation  of  this  extremity 
of  the  radius  backwards,  that  although  it  is 
rare  it  has  been  many  times  witnessed,  while 
Sir  A.  Cooper,  alluding  to  this  luxation  back- 
wards, says,  "  this  is  an  accident  which  I  have- 
never  seen  in  the  living,"  but  he  gives  an 
anatomical  account  of  the  appearances  found 
in  a  subject,  the  history  of  which  was  unknown, 
brought  into  St.  Thomas's  Hospital  for  dissec- 
tion. Having  thus  stated  the  different  opinions 
of  authors  upon  this  subject,  we  shall  proceed 
to  give  an  account  of — a,  the  luxation  of  the 
upper  extremity  of  the  radius  forwards ;  b,  of 
its  luxation  laterally  and  upwards ;  c,  of  its 
luxation  backwards ;  d,  of  its  sub-luxation ; 
e,  of  its  congenital  luxation  backwards. 

*  See  plate  xxiv.fg.  2,  in  Sir  A.  Cooper's  work. 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


73 


a.  Luxation  of  the  radius  at  the  elbow-joint 
forwards. — The  symptoms  of  this  accident  are 
as  follows :  the  fore-arm  is  slightly  bent,  but 
cannot  be  brought  to  a  right  angle  with  the  arm, 
nor  can  it  be  completely  extended  ;  when  it  is 
suddenly  bent,  the  head  of  the  radius  strikes 
against  the  fore  part  of  the  humerus,  and  pro- 
duces so  sudden  a  stop  to  its  motion  as  at  once 
to  convince  the  surgeon  that  one  bone  strikes 
against  the  other.  The  hand  is  placed  in  a 
prone  position;  but  neither  its  pronation  nor 
its  supination  can  be  completely  performed, 
although  its  pronation  may  be  nearly  complete. 
The  head  of  the  radius  may  be  felt  on  the  front 
and  upper  part  of  the  elbow-joint,  and  if  rota- 
tion of  the  hand  be  attempted,  the  bone  will 
be  perceived  to  roll;  this  last  circumstance 
and  the  sudden  stop  to  the  bending  of  the  arm 
are  the  best  diagnostic  marks  of  this  injury. 
In  the  dissection  of  this  case,  the  head  of  the 
radius  is  found  resting  in  the  hollow  above  the 
external  condyle  of  the  os  humeri.  The  ulna 
is  in  its  natural  position.  The  coronary  and 
part  of  the  capsular  ligaments  as  well  as  the 
oblique  and  a  portion  of  the  interosseous  liga- 
ments are  torn  through.  The  laceration  of  the 
latter  ligament  allows  of  the  separation  of  the 
two  bones.  The  biceps  muscle  is  shortened 
(fig-  43). 

Fig.  43. 


Luxation  of  the  radius  forwards. 

We  have  known  an  instance  in  which  this 
accident  was  produced  in  the  following  man- 
ner :  the  patient  in  endeavouring  to  protect  his 
head  from  a  blow  aimed  at  him  by  a  man  who 
with  both  hands  wielded  a  spade,  received  the 
force  and  weight  of  the  spade  on  the  edge  of 
the  ulna,  which,  at  the  same  time  that  it  pro- 
duced a  compound  fracture  of  this  bone,  also 
dislocated  the  radius  forwards.  This  latter 
complication  not  having  been  discovered  in 
time,  remained  ever  afterwards  unreduced. 

b.  Lateral  dislocation  of  the  upper  extremity 
of  the  radius. — This  is  an  accident  we  find 
alluded  to  for  the  first  time  by  Sir  A.  Cooper, 
in  the  appendix  to  the  edition  of  his  work  on 
luxations.  He  does  not  adduce  any  recent 
case  of  it,  but  states  that  Mr.  Freeman  brought 


to  his  house  a  gentleman,  aged  twenty-five, 
whose  pony  having  run  away  with  him  when 
he  was  twelve  years  old,  he  had  struck  his 
elbow  against  a  tree,  while  his  arm  was  bent 
and  advanced  before  his  head,  in  consequence 
of  which  the  olecranon  was  broken,  and  the 
radius  luxated  upwards  and  outwards  above 
the  external  condyle.  When  the  arm  was  bent, 
the  head  of  the  radius  passed  the  os  humeri ; 
he  had  a  useful  motion  of  the  limb,  but  neither 
the  flexion  nor  the  extension  was  complete. 

As  the  case  here  stated  is  the  only  one  we 
are  acquainted  with  on  record  of  luxation  of 
the  radius  upwards  and  outwards,  we  may  be 
perhaps  excused  for  exceeding  our  ordinary 
limits  by  relating  the  following  case  of  this 
accident ;  the  subject  of  it  was  a  very  intelligent 
medical  student,  about  twenty-three  years  old, 
and  we  shall  give  the  case  nearly  in  his  own 
words : — 

He  writes  as  follows  :  "  When  I  was  very- 
young,  a  blow  was  aimed  at  my  head  by  a 
person  having  a  heavy  boat-pole  in  his  hands. 
I  endeavoured  to  save  my  head  by  parrying  the 
blow  with  my  left  arm.  I  received  the  pole  on 
the  middle  and  back  part  of  the  fore-arm  with 
a  force  which  knocked  me  down,  and  caused  a 
wide  lacerated  wound  where  the  pole  came  in 
contact  with  it.  Whether  a  luxation  of  the 
radius  occurred  at  this  time  or  not  was  not 
known,  but  ever  since  the  accident  the  arm 
has  been  weak,  and  about  seven  years  ago 
the  weakness  increased,  and  it  became  liable 
to  partial  luxations  forwards  upon  the  slightest 
causes,  which  luxations  I  reduced  myself  by 
making  extension  with  my  right  arm,  until  at 
length  I  got  a  severe  fall,  which  dislocated  it 
to  such  an  extent,  forwards  and  outwards,  as  to 
defy  my  attempts  to  restore  it.  The  arm  was 
locked  in  the  flexed  position,  and  the  head  of 
the  radius  was  to  be  felt  high  up,  and  pro- 
jecting slightly  outside  the  external  condyle  of 
the  humerus.  The  biceps  muscle  was  con- 
tracted, and  its  tendon  was  very  prominent, 
hard,  and  tense,  like  a  bowstring.  The  hand 
was  supinated.  I  suffered  little  pain,  except 
when  extension  was  attempted,  when  it  became 
intense.  Sir  A.  Cooper  remarks,  in  his  cases 
of  luxation  of  the  radius  forwards,  that  the 
fore-arm  is  slightly  bent,  but  cannot  be  bent 
to  a  right  angle,  nor  completely  extended.  My 
arm  was  bent  to  an  acute  angle,  and  could  not 
admit  of  the  slightest  extension.  The  luxation 
was  reduced  by  extension,  and  in  six  weeks 
passive  motion  was  begun;  but  I  found  it 
painful  to  use  it,  and  the  head  of  the  radius 
would  often  catch  in  the  ridge  above  the  ex- 
ternal condyle,  but  on  extending  the  arm  it 
returned  with  a  noise  into  its  place.  A  month, 
however,  did  not  pass  before  I  was  one  morn- 
ing awakened  in  making  some  awkward  move- 
ment in  my  bed,  and  my  arm  became  luxated 
worse  than  ever.  On  this  occasion  the  surgeon 
who  heretofore  had  easily  replaced  the  bone 
found  it  impracticable  to  effect  it,  and  called 
in  Mr.  Colles  to  his  assistance ;  but  although 
much  force  was  used  it  was  in  vain.  From 
this  time  the  head  of  the  radius  never  was 


7-! 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


returned  back  to  its  proper  situation,  but  habi- 
tually remained  dislocated  completely  forwards 
in  front  of  the  external  condyle.  The  liga- 
ments seemed  to  have  been  so  lacerated,  and 
the  joint  felt  so  weak,  that  I  was  in  constant 
terror  lest  the  bone  should  be  further  luxated 
as  formerly,  and  that  it  should  again  slip  over 
the  external  condyle  of  the  humerus.  I  could 
extend  my  arm,  but  not  fully,  and  could  rotate 
it,  but  could  not  flex  it  sufficiently  to  use  my 
fork  at  dinner.  In  this  state  I  remained  for  six 
years,  and  in  the  winter  of  1834-5  the  radius 
was  again  luxated  laterally  over  the  external 
condyle  of  the  humerus  by  a  fall  from  my  bed. 
Now  the  difficulty  experienced  in  bringing  the 
bone  back  to  the  situation  it  had  so  long  occu- 
pied in  front  of  the  external  condyle,  was  ex- 
treme. I  went  to  the  hospital,  and  two  sur- 
geons, assisted  by  six  of  my  brother  pupils, 
could  not,  with  all  their  force,  reduce  the  bone. 
The  pulleys  were  also  now  used,  but  without  suc- 
cess. Dr.  O'Beirne  and  the  late  Dr.  M'Dowel 
were  called  into  consultation  ;  they  placed  me 
sitting  on  my  bed,  and  fixing  the  hollow  angle 
at  the  bend  of  the  elbow  against  one  of  the 
bed-posts,  they  used  great  force  to  straighten 
it,  in  which  they  succeeded;  that  is  to  say, 
they  replaced  the  bone,  not  into  its  original 
berth,  but  back  to  the  new  socket,  which  had 
been  formed  for  it  in  front  of  the  external  con- 
dyle, where  it  had  been  lodged  for  six  years 
previously  to  the  last  accident,  and  where  it 
now  remains.  At  this  moment  it  presents  all 
the  characters  assigned  to  the  luxation  of  the 
radius  forwards  ;  the  rounded  head  of  this  bone 
is  quite  prominent  in  front  of  the  external  con- 
dyle of  the  humerus,  in  which  situation  it 
seems  to  have  worked  for  itself  a  socket,  and 
behind  the  head  of  the  radius  a  deep  depres- 
sion exists.  The  arm  has  a  rounded  appear- 
ance, and  the  fore-arm  is  .much  wasted." 

This  case  seems  to  us  important  as  proving 
three  circumsi.ances  :  1 .  that  a  partial  luxation 
forwards  of  the  radius  can  exist  from  relaxation 
or  elongation  of  ligaments  ;  2 .  that  this  partial 
luxation  or  weakness  of  the  joint  is  readily 
convertible  into  the  true  luxation  forwards ; 
and,  3.  that  in  the  case  of  unreduced  luxation 
of  the  radius  forwards  the  patient  is  still  in 
danger  of  further  luxation  of  this  bone  laterally, 
or  above  the  capitulum  and  outer  condyle  of 
the  humerus. 

e.  Luxation  of  the  tipper  extremity  of'  the 
radius  backwards. — This  luxation  would  appear 
to  be  the  most  frequent  the  upper  extremity  of 
the  radius  is  liable  to,  although  it  cannot  be 
considered  a  common  accident.  When,  how- 
ever, we  consider  the  functions  of  this  joint 
and  its  form,  we  shall  not  be  surprised  to  find 
the  luxation  backwards-  more  usual  than  that 
forwards.  The  articulation  is  less  sustained 
posteriorly  by  muscular  parts  than  in  front, 
when  the  fleshy  bellies  of  the  supinators  cover 
and  support  it.  There  is  also  much  latitude 
given  to  the  movement  of  pronation,  and  the 
pronators  are  very  powerful  muscles.  During 
a  forced  pronation,  the  radius  becomes  very 
oblique,  and  its  upper  extremity  has  a  strong- 


tendency  to  pass  behind  the  axis  of  the  hu- 
merus. 

The  motion  of  supination,  on  the  contrary, 
is  not  so  frequent,  the  muscles  to  effect  it  are 
not  so  powerful,  and  the  oblique  and  interos- 
seous ligaments,  which  afford  no  restraint  in 
the  motion  of  pronation,  are,  on  the  contrary, 
soon  rendered  tense,  and  oppose  a  forced 
supination,  which  is  the  movement  most  likely 
to  be  followed  by  the  luxation  forwards.  We 
think,  therefore,  we  have  physiological  grounds 
for  our  belief  that  the  luxation  of  the  radius 
backwards  ought  to  be  the  most  frequent  lux- 
ation of  the  radius  at  the  elbow-joint.  When 
the  luxation  of  the  upper  extremity  of  the 
radius  backward  has  occurred,  the  patient 
feels  at  the  moment  a  severe  pain  in  the  region 
of  the  joint.  The  fore-arm  is  flexed,  and  the 
hand  remains  fixed  in  a  state  of  pronation. 
Supination  cannot  be  effected  either  by  the 
voluntary  action  of  muscles  or  by  force  ap- 
plied, and  each  effort,  tending  to  produce  this 
effect,  is  attended  with  a  considerable  augmen- 
tation of  pain.  The  hand  and  fingers  are  held 
in  a  moderate  state  of  flexion.  Finally,  the 
superior  extremity  of  the  radius  forms  a  mani- 
fest prominence  behind  the  capitulum  or  small 
head  of  the  humerus. 

When  the  bone  is  left  unreduced,  many  of 
the  motions  of  the  fore-arm  are  rendered  im- 
perfect, particularly  supination  ;  but  the  shoul- 
der articulation  becomes  somewhat  more  free, 
and  in  some  degree  this  circumstance  makes 
up  for  the  deficiency. 

Sir  A.  Cooper,  who  has  not  seen  any  example 
of  this  luxation  of  the  radius  backwards  in  the 
living  subject,  has  given  us  an  account  of  a  dis- 
section of  this  injury.  He  informs  us  that  in 
the  winter  of  1821  a  subject  was  brought  for  dis- 
section into  the  theatre  of  St.  Thomas's  Hos- 
pital, in  which  was  found  this  luxation,  which 
had  never  been  reduced.  The  head  of  the 
radius  was  thrown  behind  the  external  condyle 
of  the  humerus,  and  rather  to  the  lower  extre- 
mity of  that  bone.  When  the  arm  was  ex- 
tended, the  head  of  the  radius  could  be  seen  as 
well  as  felt  behind  the  externat  condyle  of  the 
humerus.  On  dissecting  the  ligaments,  the 
coronary  ligament  was  found  to  be  torn  through 
at  its  fore  part,  and  the  oblique  ligament  had 
also  given  way.  The  capsular  ligament  was 
partially  torn,  and  the  head  of  the  radius 
would  have  receded  much  more  had.  it  not 
been  supported  by  the  fascia  which  extends 
over  the  muscles  of  the  fore-arm. 

d.  Sub-luxation  of  the  tipper  extremity  of 
the  radius,  with  elongation  of  the  coronary 
ligament. — While  Boyer  denies  the  possibility 
of  any  partial  luxation  of  the  upper  extremity 
of  the  radius,  he  describes  very  clearly  an 
abnormal  condition  of  the  radio-humeral  joint, 
of  which  we  have  seen  many  examples,  and 
which  perhaps  we  may  call  a  sub-luxation. 
The  ligaments  which  connect  the  head  of  the 
radius  to  the  ulna,  in  the  cases  above  alluded 
to,  undergo  a  gradual  relaxation  and  elonga- 
tion, so  that  whenever  an  unusual  effort  is 
made  to  produce  a  strong  pronation  of  the 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


75 


fore-arm,  the  head  of  the  radius  is  permitted 
to  pass  backwards,  somewhat  behind  its  na- 
tural situation  ;  but  as  soon  as  the  effort  ceases, 
the  radius  resumes  its  natural  position  in  the 
lesser  sigmoid  cavity  of  the  ulna.  A  true  lux- 
ation in  these  cases  cannot  be  said  to  happen, 
unless  the  effort  of  pronation  is  sufficient  to 
bring  the  superior  extremity  of  the  radius 
behind  the  small  head  of  the  humerus ;  when- 
ever this  has  occurred,  then  the  sub-luxation 
is  converted  into  the  complete  luxation  of  the 
radius  backwards,  and  presents  all  the  cha- 
racters of  this  accident,  and  it  cannot  be  re- 
placed without  the  assistance  of  art.  It  is 
known  to  anatomists  that  the  radio-cubital 
joint  is  not  advanced  much  in  its  development 
in  infants  ;  that  the  lesser  sigmoid  cavity  is  as 
yet  small  and  shallow ;  and  that  the  coronary 
ligament  of  the  radius  is  proportionally  longer 
and  more  yielding  than  it  is  destined  to  be  in 
after  life.  This  articulation,  however,  is  fully 
equal,  even  at  this  earliest  period  of  life, 
to  sustain  any  efforts  that  its  own  pronator 
muscles  can  communicate  to  it ;  but  it  is 
by  no  means  constructed  so  as  to  be  able 
to  resist  those  forced  movements  of  pronation 
and  stretching  we  see  too  frequently  given  to 
the  fore-arms  of  infants  of  a  tender  age,  by 
their  attendants,  who  in  lifting  them  from  the 
ground  usually  seize  them  by  the  fore-arms, 
these  being  at  the  time  in  a  full  state  of  pro- 
nation. Thus  we  find  that  in  delicate  children 
the  foundation  is  laid  for  that  elongation  of 
the  coronary  ligament,  which  ends  in  the  con- 
dition of  this  joint  we  have  denominated  sub- 
luxation. We  have  usually  observed  that  the 
subjects  of  this  affection  were  delicate  from 
their  youth,  and  that  sometimes  only  one, 
and  that  frequently  both  arms  were  affected ; 
that  in  all  cases  the  extremity  was  more  or  less 
deformed,  having  a  bowed  appearance,  the 
convexity  being  external ;  that  a  very  evident 
protuberance  could  be  seen  and  felt  in  the 
situation  of  the  head  of  the  radius  ;  and  that 
the  patient  had  nearly  perfect  use  of  the  arm, 
although  he  could  neither  fully  flex  nor  extend 
it.  When  the  surgeon  places  his  thumb  on 
the  external  condyle  of  the  humerus  and  head 
of  the  radius  in  one  of  these  cases,  and  at  the 
same  time  has  the  fore-arm  supinated,  the  head 
of  the  radius  is  felt  to  rotate  in  its  proper  place, 
and  on  its  axis,  as  in  its  perfect  condition  ; 
but  if  now  a  forced  movement  of  pronation  be 
given  to  the  head  of  the  radius,  the  latter  will 
be  observed  to  slip  backwards  towards  the 
olecranon  process  :  every  time  the  patient  him- 
self fully  pronates  the  fore-arm,  the  sub-lux- 
ation occurs,  and  in  supination  the  radius 
resumes  its  place  again.  This  relaxation  of 
the  ligaments  of  the  radio-cubital  joint,  no 
matter  how  produced,  at  all  events  predisposes 
those  affected  with  it  to  the  more  complete 
luxation  of  the  radius  backwards. 

e.  Congenital  or  original  luxation  of  the 
superior  extremity  of  the  radius  backward,^ — 
Dupuytren  is  the  first  pathologist  who  has 
spoken  of  the  congenital  luxation  of  the 
radius;   he  met  with  a  case  of  the  kind  in 


dissection,  and  described  it  in  his  lectures. 
He  found  that  the  superior  extremity  of  each 
radius  had  abandoned  its  natural  situation, 
and  was  found  situated  behind  the  inferior 
extremity  of  the  humerus,  having  passed  this 
extremity  an  inch  at  least.  This  disposition 
being  absolutely  the  same  on  each  side  of  the 
body,  there  existed  no  difference  between  these 
two  luxations,  which  were  probably  conge- 
nital. It  is  also  stated  that  Dupuytren  had 
mentioned  that  about  twenty  or  twenty-five 
years  before  he  dissected  the  case  now  alluded 
to,  he  had  seen  a  case  nearly  similar,  but  he 
was  unwilling  to  speak  positively  on  these 
cases,  as  the  history  was  unknown,  and  acci- 
dent or  disease  might  have  produced  similar 
results. 

Cruveilhier,  in  his  very  valuable  work  on 
Pathological  Anatomy,  quotes  the  above  ob- 
servations from  Dupuytren's  lectures,  and 
seems  to  disagree  entirely  with  the  celebrated 
surgeon  of  the  Hotel-Dieu,  advancing  it  as 
his  opinion,  that  it  vvould  be  much  more  na- 
tural to  suppose  that  the  cases  described  by 
Dupuytren  were  not  congenital,  but  rather 
very  old  luxations,  a  long  time  left  unre- 
duced. 

It  is  very  true  that  Dupuytren  speaks  with 
hesitation  about  the  matter,  as  he  appears  to 
have  met  with  but  two  cases,  nor  can  any  one 
speak  with  certainty  on  this  subject,  until  ob- 
servation on  the  living,  and  anatomical  in- 
vestigations, shall  be  combined  to  elucidate 
the  matter ;  but  we  think  that  already  enough 
can  be  adduced  to  shew,  that  we  have  strong 
grounds  for  believing  that  such  a  congenital 
defect  as  luxation  of  the  upper  extremity  of 
the  radius  backwards  may  be  occasionally  met 
with,  and  this  is  an  opinion  we  think  our- 
selves authorised  to  advance,  because  of  the 
facts  and  reasons  we  can  adduce  to  support  it. 

In  the  Museum  of  the  Royal  College  of  Sur- 
geons in  Ireland,  there  is  a  specimen,  which 
the  writer  considers  to  be  one  of  congenital  lux- 
ation of  the  upper  extremity  of  the  left  radius 
backwards;  fig.  44  is  a  representation  of  it. 
The  outer  condyle  of  the  humerus  exists,  but 
in  front  of  it  there  is  no  rounded  head  or 
capitulum  for  the  radius,  or  any  trace  of  the 
usual  convex  articular  surface  ever  having 
existed.  The  coronoid  process  and  great  sig- 
moid cavity  of  the  ulna  are  unusually  large 
transversely,  and  stretch  almost  the  whole  way 
across  the  lower  articular  extremity  of  the 
humerus,  which  is  entirely  formed  into  one 
single  trochlea  wider  than  natural.  The  head 
of  the  radius,  which  seems  never  to  have  been 
adequately  developed,  is  situated  behind  the 
plane  of  the  outer  condyle  of  the  humerus. 
The  tubercle  of  the  radius  is  much  enlarged, 
and  leans  against  the  lesser  sigmoid  cavity  of 
the  ulna,  while  the  neck  of  the  radius,  directed 
somewhat  backward,  is  twice  its  natural  length, 
and  instead  of  reaching  merely  to  the  level  of 
the  lesser  sigmoid  cavity  of  the  ulna,  stretches 
as  high  up  along  the  ulna  as  to  reach  near  to 
the  level  of  the  summit  of  the  olecranon  pro- 
cess, while  the  carpal  extremities  of  the  radius 


76 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


and  ulna  are,  in  their 
natural  state,  on  an  even 
line  with  each  other. 
There  is  scarcely  any 
interosseous  interval,  the 
bones  seem  so  closely 
connected  with  each  other. 
Indeed,  from  the  inspec- 
tion of  this  preparation, 
we  may  justly  infer  that 
the  fore-arm  during  life 
had  remained  much  in 
a  state  of  semiflexion  on 
the  arm,  and  of  rigid 
pronation,  and  that  the 
movement  of  supination 
was  nearly  impracticable. 
This  defective  formation, 
or  atrophy  of  the  capitu- 
lum  and  increased  deve- 
lopement  of  the  trochlea 
of  the  humerus,  which 
was  so  formed  to  ac- 
commodate itself  to  the 
unusual  breadth  acquired 
by  the  coronoid  process 
and  the  whole  of  the 
ulna,  must  not  be  con- 
sidered unprecedented. 
We  find,  by  referring  to 
the  beautiful  work  of 
Sandifort,  (the  Museum 
Anatomicum,  table  ciii. 
fig.  3,)  a  case  similar  to 
the  above  delineated 
(fig.  45).  In  referring 
to  it,  the  author  states 
that  the  bones  of  the 
fore-arm  were  anchylosed , 
that  the  form  of  the  ca 
pitulum  was 
the  head  of  the  radius 
■was  luxated  completely 
backwards,  and  that  the 
ulna  alone  remained  in 
articulation  with  the  hu- 
meri s ;  the  parallelism 
between  these  two  cases 
will  be  still  more  fully 
seen,  when,  speaking  of 
the  lower  articular  extre- 
mity of  the  humerus,  we 


.     ;  Congenital  luxation  of  the 

lost,   tnat     Tadius  backlvarfom 


Fig.  45. 


■ 


'  IP 
1 1 1 

k  it 


find  that  he  says,"  Figura  A 

ergocapituliperiil.Rotula  /llOHMHB|>t 

unica,  sed  major  forma-  I^J^^|' 

tur;"   and  of  the  ulna, 

"  insignem  acquisivit  am- 

plitudinem  et  totam  infe-  , 
r.  .    ,  Vonqemtal  malformation 

norem  ossis  humeri  par-    »f  HgU  hJumerm  _ 

tem  admittere  potuit.  trochlea  enlarged— no 

In  examining  very  capitulum. 
lately  the  splendid  col- 
lection of  morbid  specimens  contained  in 
the  Museum  of  Guy's  Hospital,  the  writer's 
attention  was  caught  by  observing  a  pre- 
paration of  the  radius  and  ulna,  belonging, 
he  is  certain,  to  the  same  class  of  diseases 
now  under  consideration,  namely,  congenital 
luxations  of  the  radius.    In  this  preparation 


there  is  a  very  oblique  relative  position  of  the 
bones  of  the  fore-arm  to  each  other.  While 
their  carpal  extremities  are  exactly  upon  a  line 
with  each  other  below,  the  neck  of  the  radius 
is  elongated  upwards,  and  the  head  of  this 
bone  is  displaced  much  backwards,  and  is 
situated  behind  and  below  the  outer  condyle 
of  the  humerus,  and  reaches  nearly  to  the 
summit  of  the  olecranon.  The  coronoid  pro- 
cess and  great  sigmoid  cavity  of  the  ulna  have 
acquired  much  breadth,  and  what  is  remark- 
able in  this  case,  and  in  which  it  differs  from 
any  other  we  have  seen,  is,  that  a  process  of 
caries  had  been  going  on  in  the  articulation. 
Cruveilhier  has  given  four  drawings  of  two 
cases  of  complete  luxation  backward  of  the 
radius,  which  he  however  does  not  consider  to 
be  congenital.  Nor  is  it  in  our  power  abso- 
lutely to  prove  that  they  are  specimens  of 
congenital  luxations  backwards,  although  we 
feel  persuaded  that  all  the  cases  we  have  re- 
ferred to,  these  inclusive,  are  very  curious 
specimens  of  this  congenital  deformity  of  the 
radio-humeral  articulation. 

The  previous  history  of  all  the  cases  we 
have  collected  is  totally  unknown ;  it  is  re- 
corded of  them  all,  that  the  arm  was  re- 
markable for  its  deficient  development,  that 
the  fore-arm  was  in  a  state  of  demi-pro- 
nation  and  demi-flexion,  that  the  movement 
of  extension  was  incomplete,  and  of  su- 
pination impossible.  Cruveilhier,  in  the  ac- 
count he  has  given  of  both  his  cases,  states 
that  the  superior  extremity  of  the  radius  was 
at  the  level  of  the  summit 
of  the  olecranon  process 
(Jig-  46),  and  that  the  infe- 
rior or  carpal  extremity  of 
the  two  bones  of  the  fore- 
arm were  on  the  same  pre- 
cise line  below,  and  that  no 
deformity  here  existed.  The 
head  of  the  radius  and  tu- 
bercle were  deformed,  or  ra- 
ther imperfectly  developed, 
while  there  was  an  elonga- 
tion of  the  neck  of  the  ra- 
dius upwards  for  more  than 
an  inch.  Cruveilhier  can- 
not concur  with  those  who 
consider  these  cases  as  ex- 
amples of  congenital  luxa- 
tions, but  looks  upon  them 
as  old  luxations,  which  had 
been  left  unreduced. 

For  our  part  we  cannot 
see  in  these  pathological  ob- 
servations any  thing  to  con- 
vince us  that  any  one  of  the 
cases  alluded  to  was  an  old 
luxation  originally  produced 
by  accident  or  disease.  Sup- 
pose, for  argument  sake,  it 
be  admitted  that,  from  long 
disease,  the  form    of  the 

,   capitulum    was  altogether 
Malformation  of  the  j  £     fa     t,       d;  nQ 
radius,   in   winch  ,     >  ...  , 

it  was  found  as  longer  m  contact  with  it,  and 
long  as  the  ulna,     that  the  acquired  breadth  of 


Fig.  46. 


1 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT.  77 


the  sigmoid  cavity  of  the  ulna  was  the  result  of 
a  natural  effort  to  compensate  for  the  loss  of 
strength  the  joint  suffered  from  the  dislocation 
of  the  radius.  Still,  supposing  it  possible  that 
the  surface  of  the  capitulum  of  the  humerus 
could  be  so  completely  removed,  under  such 
circumstances,  as  we  find  it  was  in  the  cases  of 
which  Jigs.  44  and  45  are  delineations,  we  may 
ask,  is  it  likely,  from  accident  or  disease, 
that  both  elbow-joints  should  be  similarly 
affected,  as  they  were  in  Dupuytren's  cases. 
Another  circumstance  in  our  mind  cannot  be 
accounted  for,  unless  by  supposing  these  cases 
congenital,  namely,  the  alteration  and  great 
elongation  of  the  neck  of  the  radius.  "  L'ex- 
tremite  superieure  de  chaque  radius  avait 
abandonne  sa  situation  naturelle,  se  trouvait 
place  derriere  l'extremite  inferieure  de  l'hu- 
merus,  et  depassait  cette  extremite  d'un 
pouce  au  moins.  Cette  disposition  etait  ab- 
solument  la  meme  de  chaque  cote  du  corps." 
We  know  of  no  process  which  could  take 
place  in  the  head  and  neck  of  the  radius  after 
it  had  been  dislocated,  which  could  satis- 
factorily account  for  the  elongation  of  the 
radius,  which  has  been  remarked  in  these 
cases.  While  looking  on  them  as  congenital, 
we  need  not  be  surprised  at  it ;  for  we  have 
known  the  neck  of  the  femur  elongated  and 
atrophied,  in  the  case  of  congenital  luxation 
of  the  femur,  and  have  very  frequently  seen 
the  lower  extremity  of  the  ulna  exceed  in  length 
by  half  an  inch  the  corresponding  extremity 
of  the  radius  ;  and  these  were  cases  in  which 
no  doubt  could  be  entertained  that  they  were 
congenital. 

Disease. — -Acute  and  chronic  inflammation 
produces  effects  on  the  membranes,  cartilages, 
and  bones  entering  into  the  composition  of  the 
elbow-joint,  which  will  be  found  nearly  analo- 
gous to  those  which  the  same  morbid  action  pro- 
duces on  similar  structures  in  other  articulations. 
A  few  local  peculiarities,  if  we  may  so  call  them, 
when  the  elbow  is  the  seat  of  the  acute  or 
chronic  disease,  should  alone  occupy  our  atten- 
tion here. 

Synovitis  of  the  elbow-joint,  uncombined 
with  any  affection  of  the  other  structures,  is 
rare  ;  it  may,  however,  present  itself  either  in 
the  acute  or  subacute  form.  Increased  effusion 
of  fluid  into  the  joint,  accompanied  with  the 
usual  local  and  sympathetic  phenomena  of  in- 
flammation, is  the  result.  Two  well-marked 
oblong  swellings  at  each  side  of  the  olecranon 
process  in  these  cases  first  present  themselves, 
which  after  a  time,  if  the  disease  proceeds, 
join  and  form  one  swelling,  which  extends  up 
the  back  of  the  arm,  occupying  the  cellular  in- 
terval existing  between  the  back  part  of  the 
humerus  and  the  front  of  the  triceps  muscle, 
opposite  to  the  outer  condyle  of  the  humerus 
and  head  of  the  radius;  the  supinators  arising 
here  are,  in  severe  cases,  occasionally  elevated 
and  thrown  out  from  the  bones  by  a  soft  tumour, 
which,  upon  examination,  conveys  to  the  fingers 
a  distinct  feeling  of  a  fluid  contained  beneath. 
The  nature  of  the  accumulated  fluid  will,  when 
the  joint  is  cut  into,  be  found  to  vary.  When 
the  effusion  has  followed  an  acute  attack  of  in- 


flammation of  the  membrane,  it  will  be  gene- 
rally found  to  be  purulent,  though  sometimes 
we  have  observed  the  quality  of  the  synovia 
but  little  altered,  except  that  it  was  more  or 
less  turbid.  When  the  contents  of  the  synovial 
sac  have  been  washed  away,  the  membrane  will 
be  seen  to  be  highly  vascular,  and  the  ves- 
sels of  the  subsynovial  tissue  congested 
with  blood,  and  its  cells  infiltrated  with  se- 
rum; while,  if  fine  injection,  coloured  with 
vermillion,  is  thrown  into  the  vascular  system 
of  these  parts,  the  unusual  redness  the  mem- 
branes assume  can  only  be  compared  in  height 
of  colouring  to  the  membrane  of  the  eye  in 
acute  conjunctivitis.  With  this  intense  red- 
ness of  the  surrounding  membranes  is  strongly 
contrasted  the  appearance  of  the  cartilages  of 
the  joint;  these,  but  little  altered  from  their 
natural  colour,  are  seldom  in  this  articulation 
found  covered  with  vascular  membranes,  and 
even  when  the  surrounding  structures  are  mi- 
nutely injected,  the  fluid  cannot  be  made  to 
penetrate  the  synovial  investment  of  the  carti- 
lages. 

Cartilage. — When  acute  inflammation  has 
existed  in  the  synovial  membrane  or  bones  of 
the  elbow-joint,  the  articular  cartilages  covering 
these  will  very  frequently  be  found  to  have 
assumed,  in  patches,  a  dull  yellow  colour ;  in 
the  latter  discoloured  points  the  cartilage  is  soft- 
ened, and  a  blunt  probe  slightly  pressed  will 
sink  into  its  structure,  and  its  subjacent  surface 
will  be  found  to  be  detached.  A  new  vascular 
membrane  having  been  interposed  between  the 
cartilage  and  the  cancellous  structure  of  the 
bone,  this  elevation  and  partial  detachment  of 
the  articular  cartilages  from  the  heads  of  the 
bone,  and  interposition  of  a  new  organized  mem- 
brane, are  probably  the  usual  preludes  to  those 
other  changes  we  notice.  Thus  sometimes  a 
leaf  or  flap  of  the  articular  cartilage,  adherent 
only  by  an  edge,  hangs  into  the  cavity  of  the 
joint,  and  again  fragments  of  this  structure 
completely  detached  are  found  loose  in  the  in- 
terior of  the  articulation.  In  these  instances 
there  is  reason  to  conjecture  that  the  diseased 
action  which  detached  the  cartilage  began  on 
the  surface  of  this  structure  contiguous  to  the 
bone.  We  have  occasionally,  however,  evidence 
of  ulcerative  absorption  having  commenced  on 
the  free  surface  of  the  cartilage.  The  peculiar 
worm-eaten  appearance  which  the  surfaces  of 
cartilages  next  the  cavity  of  the  joint  occa- 
sionally present,  and  which,  wherever  it  exists, 
is  considered  by  many  pathologists  to  be  the 
result  of  a  process  of  ulceration  which  had  be- 
gun on  the  free  surfaces  of  the  articular  carti- 
lages, has  been  occasionally  though  rarely  seen 
in  the  elbow-joint ;  much  more  frequently  in 
examining  elbow-joints  which  have  been  the 
seat  of  disease,  the  articular  surfaces  of  the  bones 
have  been  found  extensively  divested  of  their 
cartilages  ;  a  few  patches  of  them  alone  here 
and  there  remain  ;  and  these,  though  apparently 
thinner  than  natural,  are  of  their  ordinary  tex- 
ture, and  are  firmly  adherent  to  bone. 

Such  extensive  removal  of  cartilage,  which 
has  exposed  the  cancelli  of  the  heads  of  the 
bones,  has  generally  been  the  result  of  some 


78 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


very  violent  attack  of  inflammation,  which,  no 
matter  in  what  situation  it  had  originated,  ulti- 
mately we  find  had  not  spared  any  of  the  tis- 
sues entering  into  the  formation  of  the  articu- 
lation. 

Bone. — The  elastic  white  swelling  (which  is 
one  of  the  usual  external  signs  of  this  articular 
caries  when  the  bones  of  the  elbow-joint  are  the 
seat  of  the  affection)  is  always  situated  poste- 
riorly, and  gives  a  characteristic  appearance 
and  a  rounded  form  to  the  back  part  of  the 
elbow-joint,  which  cannot  be  mistaken  nor 
misunderstood.  The  wasted  appearance  of  the 
arm  above  and  of  the  fore-arm  below  makes 
this  swelling  more  conspicuous,  and  the  whole 
limb  remains  habitually  in  the  semiflexed  posi- 
tion, with  the  fore-arm  somewhat  prone  ;  every 
movement  of  the  articulation  causes  the  patient 
much  pain.  The  disease,  thus  arrived  at  its 
second  or  third  stage,  may  remain  stationary 
for  a  time  or  terminate  in  an  anchylosis  of  the 
bones ;  commonly,  however,  the  morbid  pro- 
cess goes  on.  Luxation  of  one  or  both  bones 
of  the  fore-arm  occurs,  symptomatic  abscesses 
present  themselves,  and  these  after  a  time  make 
their  way  to  the  surface,  and  discharge  their 
contents  through  openings,  sometimes  near, 
and  frequently  at  a  distance  from  the  joint;  and 
thus,  at  length,  we  see  formed  direct  outlets  as 
well  as  sinuses  and  fistulous  canals,  which  give 
exit  to  exhausting  discharges.  The  pain  and 
irritation  attendant  on  the  disease  itself,  added 
to  all  these,  give  rise  to  hectic  fever,  which  too 
frequently  nothing  but  the  desperate  measure 
of  amputation  will  arrest.  The  disease,  which 
produces  such  serious  consequences,  often  be- 
gins very  insidiously,  either  in  the  head  of  the 
radius  and  external  condyle  of  the  humerus,  or 
in  the  trochlea  of  this  bone  and  the  great  sig- 
moid cavity  of  the  ulna.  When  the  disease 
begins  at  the  radial  side,  the  pain  runs  along 
the  course  of  the  musculo-spiral  nerve,  and 
there  is  a  manifest  swelling  externally  in  the 
situation  of  the  radio-humeral  articulation  : 
although  there  is  even  now  a  marked  tendency 
in  the  fore-arm  to  remain  in  a  semiflexed  posi- 
tion, still  gentle  flexion  and  limited  extension 
are  admissible  ;  but  when  the  radius  is  pressed 
against  the  humerus,  and  a  movement  of  rota- 
tion at  the  same  time  is  given  to  the  fore-arm, 
much  pain  is  complained  of.  The  disease  may 
go  on,  confining  itself  chiefly  to  the  radial  side 
of  the  elbow-joint  through  its  first  stage  of 
pain  and  swelling ;  through  its  second  of  effu- 
sion of  fluids  and  relaxation  of  the  coronary  and 
external  lateral  ligament;  and,  thirdly,  to  dislo- 
cation backwards  of  the  head  of  the  radius, 
and  even  to  suppuration  and  discharge  of  mat- 
ter through  an  ulceration  or  slough  of  the  inte- 
guments. 

When  the  caries  has  commenced  in  one  of 
the  opposed  surfaces  of  the  trochlea  of  the 
humerus  or  great  sigmoid  cavity  of  the  ulna, 
the  swelling  and  effusion  are  first  noticed  in- 
ternally at  the  side  of  the  olecranon  and  inter- 
nal condyle.  The  pain  extends  to  the  wrist 
along  the  course  of  the  ulnar  nerve  ;  the  fore- 
arm is  in  this  case  also  in  a  state  of  semi- 
flexion, and  any  attempt  to  extend  or  increase 


the  degree  of  flexion  causes  very  severe  pain, 
while,  on  the  contrary,  a  movement  of  rotation 
of  the  fore-arm  is  permitted.  If  the  disease  pro- 
ceeds, the  great  sigmoid  cavity  of  the  ulna  be- 
comes wider  and  deeper,  and  the  humerus  ad- 
vances on  the  coronoid  process ;  the  internal 
lateral  ligaments  are  relaxed,  and  the  triceps 
drags  back  the  fore-arm,  so  that  the  olecranon 
process  projects  somewhat  posteriorly,  and  there 
is  a  tendency  to  a  displacement  backwards. 

Whether  the  disease  has  originated  on  the 
radial  or  ulnar  side  of  the  joint,  it  very  generally 
spreads  so  as  to  involve  the  articular  surfaces 
of  the  three  bones,  and  now  the  disease,  termed 
scrophulous  white  swelling,  becomes  fully  esta- 
blished, and  is  easily  recognized  by  the  usual 
signs.  Besides  dislocation  backwards,  either  of 
the  radius  or  of  the  ulna  singly,  or  of  both 
these  bones  together,  lateral  displacements  of 
the  bones  of  the  fore-arm  at  the  elbow  have 
been  noticed  as  a  consequence  of  caries ;  nor 
need  we  be  surprised  at  such  variety  of  posi- 
tion being  assumed  by  the  bones,  when  inflam- 
mation has  softened  the  strong  lateral  ligaments 
and  caused  their  ulceration.  While  the  patient 
is  confined  to  bed  or  to  the  horizontal  posture, 
the  mere  position  which  is  given  to  the  fore-arm 
on  the  pillow  will  influence  the  direction  of 
the  displacement  that  will  occur.  We  have 
seen,  under  such  circumstances,  complete  late- 
ral displacement  of  both  bones  of  the  fore-arm 
outwards.  The  internal  condyle  of  the  hume- 
rus pressing  against  the  integuments  covering 
it  had  caused  a  round  slough,  through  which 
the  internal  condyle  of  this  bone  protruded, 
while  the  rounded  head  of  the  radius  had  on 
the  outer  side  caused  a  similar  slough  and 
ulceration  of  the  integuments,  through  which 
the  upper  cup-like  extremity  of  this  bone  had 
protruded. 

This  lateral  displacement  of  both  bones  of 
the  fore-arm  outwards,  whether  occurring  sud- 
denly from  accident,  or  slowly  from  the 
effects  of  articular  caries,  if  it  be  complete, 
must  always  (we  imagine)  be  followed  by  a 
consecutive  dislocation  upwards.  In  this  case 
of  caries  above  alluded  to,  we  found  the  whole 
extremity  somewhat  shortened,  that  the  hand 
remained  habitually  prone,  and  that  the  fore- 
arm (in  a  state  of  semiflexion  as  to  the  arm) 
was  directed  with  considerable  obliquity  in- 
wards. It  was  plain  that  the  causes  of  all 
these  external  signs  were,  that  both  bones  of 
the  fore-arm  having  their  normal  relation  to 
each  other,  were  first  carried  completely  out- 
side the  inferior  extremity  of  the  humerus,  and 
were  then  drawn  upwards  above  the  level  of 
the  outer  condyle  of  this  bone.  The  olecranon 
process  was  not  thrown  at  all  backwards,  but 
was  situated  immediately  above  and  outside 
the  external  condyle  of  the  humerus  ;  the  coro- 
noid process  was  in  front  of  this  bone;  the 
inner  semilunar  edge  of  the  great  sigmoid  ca- 
vity therefore  corresponded  to  the  convexity  of 
the  outer  side  of  the  humerus,  and  seemed,  as 
it  were,  to  embrace  this  bone  here  so  as  to  for- 
bid any  further  retraction  of  the  fore-arm. 
When  we  proceed  to  examine  an  elbow-joint 
which  has  been  the  seat  of  a  scrophulous  white 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


79 


swelling  that  had  presented  the  usual  charac- 
ters of  this  disease  in  its  advanced  form,  we 
usually  notice  the  surface  of  the  skin  studded 
over  here  and  there  with  the  orifices  of  fistulous 
canals  ;  these  are  found  generally  to  have  pro- 
ceeded by  a  winding  course,  either  from  the 
cavity  of  the  elbow-joint  or  from  the  cancellous 
structure  of  the  bones,  or  from  both  these 
sources.  W  hen  a  section  is  made  of  the  bones 
in  this  advanced  period  of  the  disease,  they 
will  generally  be  found  to  be  softened  in  the 
interior,  and  to  contain  a  fatty  or  yellowish 
cheese-like  matter  in  their  cells  ;  when  exam- 
ined in  an  earlier  stage  of  this  scrophulous 
caries,  these  organs  are  generally  found  to  be  pre- 
ternaturally  red  and  vascular,  and  with  much 
less  proportion  of  earthy  matter  than  natural, 
so  that  they  admit  not  only  of  being  cut  with  a 
knife  without  turning  its  edge,  but  yield  and 
are  crushed  under  very  slight  pressure. 

We  have  also  occasionally  opportunities  of 
examining  the  joint  when  the  process  of  caries 
would  appear  to  have  been  arrested  and  to 
have  given  place  to  a  new  growth  of  bony  vege- 
tations around  the  joint ;  under  such  circum- 
stances, conical  granulations,  several  lines  in 
length,  shoot  out  like  stalactites  around  the 
trochlea  of  the  humerus  and  from  the  olecranon 
and  coronoid  processes  of  the  ulna  ;  the  bones 
are,  however,  in  these  specimens  remarkably 
light,  porous,  and  friable.  In  some  cases, 
however,  the  caries  of  the  bone  has  altogether 
ceased,  and  a  process  of  anchylosis  has  been  es- 
tablished, and  the  fore-arm  is  flexed  on  the  arm : 
a  section  through  the  elbow-joint  longitudinally 
will  in  such  cases  frequently  exhibit  a  com- 
plete continuation  of  the  cancelli  through  the 
joint  from  the  cells  of  the  humerus  to  those  of 
the  radius  and  ulna. 

Rheumatism. — The  elbow-joint,  like  all  the 
other  articulations,  is  liable  to  attacks  of  acute 
rheumatic  inflammation,  the  external  signs  of 
which  differ  but  little  from  those  which  we 
observe  to  attend  an  ordinary  case  of  acute 
synovitis.  The  disease,  however,  seldom  fixes 
itself  for  any  time  upon  this  or  any  one  joint 
in  particular  and  usually  terminates  favourably, 
so  that  opportunities  seldom  occur  of  ascer- 
taining by  anatomical  examination  the  effects 
of  this  species  of  inflammation  in  the  different 
structures  of  the  elbow-joint.  But  this  articu- 
lation is,  in  the  adult  and  in  those  advanced  in 
life,  affected  by  a  disease  which,  for  want  of  a 
better  name,  is  termed  chronic  rheumatism, 
the  anatomical  characters  of  which  are  very 
remarkable,  yet  they  never  have  received 
from  pathologists  that  attention  they  appear 
to  us  to  deserve.  In  these  cases  the  elbow- 
joint  becomes  enlarged  and  deformed;  its  or- 
dinary movements,  whether  of  flexion,  exten- 
sion, or  rotation,  become  restricted  within  very 
narrow  limits ;  and  when  we  communicate 
to  the  joint  any  of  these  motions,  the  patient 
complains  of  much  pain,  and  a  very  remarkable 
crepitation  of  rough  rubbing  surfaces  is  per- 
ceived :  a  careful  external  examination  of  the 
joint  will  in  such  circumstances  enable  us  to 
detect  foreign  bodies  in  the  articulation.  Some 
of  them  are  small,  but  others  occasionally  are 


met  with  of  a  very  large  size,  and  can  easily  be 
felt  through  the  integuments.    Sometimes  the 
synovial  membrane  of  the  joint  itself  is  much 
distended  with  fluid,  and  the  bursa  of  the  ole- 
cranon is  likewise  affected,  in  which  small  fo- 
reign bodies  are  also  to  be  detected  :  sometimes, 
however,  there  would  appear  to  exist  in  the  in- 
terior of  the  joint  even  less  synovia  than  natural. 
The  muscles  of  the  arm  and  fore-arm  for  want  of 
use  are  more  or  less  wasted  and  atrophied.  As 
the  external  appearances  vary,  so  also  do  we  find 
the  anatomical  characters  of  the  disease  to  pre- 
sent varieties,  some  of  which  deserve  notice. 
We  have  found  the  most  general  abnormal  ap- 
pearance to  be  that  the  cartilages  are  removed 
from  the  heads  of  the  bones  which  are  greatly 
enlarged,  and  that  these  articular  surfaces  are 
covered   by  a  smooth  porcelain-like  deposit, 
and  after  a  time  attain  the  polish  and  smooth- 
ness of  ivory  :   the  trochlea  of  the  humerus, 
also,  and  corresponding  surface  of  the  great 
sigmoid  cavity  of  the  ulna  are  also  marked 
with  narrow  parallel  sulci  or  grooves  in  the  di- 
rection of  flexion  and  extension.   In  these  cases 
the  radio-humeral  joint  is- likewise  affected,  the 
head  of  the  radius  becomes  greatly  enlarged, 
and  it  assumes  quite  a  globular  form,  while  the 
anterior  and  outer  part  of  the  lower  extremity 
of  the  humerus  will  have  its  capitulum  or  con- 
vex head  not  only  removed,   but  here  the 
humerus  will  be  found  to  be  even  excavated  to 
receive  the  head  of  the  radius,  and  to  accom- 
modate itself  to  the  new  form  it  has  acquired 
from  disease.    In  many  cases  where  the  radius 
had  become  thus  enlarged  and  of  a  globular 
form,  the  writer  has  found  the  cartilage  removed 
altogether  and  its  place  occupied  by  an  ivory- 
like enamel.    In  two  examples  he  has  seen  a 
depression  or  dimple  in  this  rounded  head  of 
the  radius,  similar  to  what  naturally  exists  in 
the  head  of  the  femur,  and  in  these  two  cases, 
strange  to  relate,  a  distinct  bundle  of  ligament- 
ous fibres  analogous  to  a  round  ligament  passed 
from  the  dimple  or  depression  alluded  to,  con- 
necting this  head  of  the  radius  to  the  back 
part  of  the  sigmoid  cavity  of  the  ulna.  In 
some  few  cases,  when  the  external  signs  of  this 
chronic  disease  in  the  elbow-joint  were  present, 
we  have  found  the  bones  of  this  articulation 
enlarged,  hard,  and  presenting  a  rough  porous 
appearance,  while  the  cartilage  was  entirely 
removed ;  but  in  these  specimens  no  ivorv 
deposit  was  formed.     These  were  cases  in 
which  the  same  disease  existed  locally,  and  the 
same  disposition  prevailed  in  the  constitution  ; 
but  from  the  bones  having  been  kept  in  a  state 
of  quietude,  the  rough  surfaces  of  the  articular 
extremities  had  not  been  smoothed  by  the 
effects  of  friction,  nor  an  ivory-like  enamel 
formed.    We  believe  that  in  such  cases,  were 
life  prolonged,  anchyloses  would  be  established : 
in  other  instances  the  head  of  the  radius  has 
not  been  found  enlarged  as  above  described, 
but  otherwise  altered  from  its  natural  form. 
The  superior  articular  extremity  of  this  bone 
has  been  found  excavated  from  before  back- 
wards, its  outline  not  being  circular  nor  exactly 
oval  but  ovoidal,  accurately  representing  on  a 
small  scale  the  glenoid  cavity  of  the  scapula. 


80 


ABNORMAL  CONDITION  OF  THE  ELBOW-JOINT. 


It  may  be  remarked  that  one  of  our  patients, 
a  man,  aged  sixty,  in  the  surgical  wards  of 
the  House  of  Industry,  who  had  for  many 
years  suffered  from  the  severest  forms  of  chronic 
rheumatism  in  all  the  articulations,  got  diarrhoea 
and  died.  The  writer  had  previously  noted 
in  particular  the  condition  of  the  right  elbow- 
joint;  the  motions  of  flexion  and  extension 
were  very  limited,  attended  with  much  crepi- 
tation, and  caused  to  the  patient  very  great 
pain.  The  exact  condition  of  the  bones 
described  in  the  preceding  paragraph  existed, 
and  the  loss  of  the  circular  outline  of  the 
radius  fully  accounted  for  what  we  had  in  this 
case  previously  noted,  viz.  that  to  remove  the 
hand  from  the  state  of  pronation  in  which  it 
habitually  remained,  or  to  communicate  any 
movement  of  rotation  to  the  radius  was  nearly 
impracticable;  the  glenoid-shaped  surface  for 
the  head  of  the  radius  allowed  of  flexion  and 
extension  in  the  radio-humeral  articulation,  but 
any  except  the  perfect  circular  form  was  ill- 
suited  to  permit  any  rotatory  movement  of  the 
radius  on  the  ulna.  This  then  is  a  peculiar 
disease  which  causes  a  complete  removal  of 
the  articular  cartilage  from  the  head  of  the 
bones  of  the  elbow-joint,  so  that  the  porous  sub- 
stance of  the  bones  becomes  exposed  :  they  do 
not  become  carious,  but  on  the  contrary  they 
are  enlarged,  hard,  aud  their  surfaces  seem  to 
expand.  If  the  joint  be  much  used,  the  effects 
of  friction  become  evident;  if  kept  at  rest,  they 
are  rough,  and  anchylosis  may  take  place. 

From  the  phenomena  we  observe  in  the 
variety  of  cases  that  present  themselves,  we 
may  infer  that,  when  this  disease  affects  the 
elbow-joint,  in  whichever  bone  most  vitality 
exists  and  most  active  nutrition  is  going  on, 
enlargement  would  appear  to  take  place,  while 
in  the  bone  which  is  softer  arid  in  which  the 
process  of  nutrition  is  least,  the  effects  of  fric- 
tion become  of  course  most  manifest.  Thus, 
in  some  cases,  as  already  mentioned,  we  have 
found  the  head  of  the  radius  greatly  enlarged 
and  of  a  globular  form,  and  the  outer  condyle  of 
the  humerus  excavated  to  adapt  itself  to  this 
convexity,  while  on  the  contrary,  in  other  cases 
the  outer  condyle  of  the  humerus  seemed  to 
have  been  the  seat  of  active  nutrition,  and  the 
head  of  the  radius  to  have  been  rendered  soft  and 
to  have  yielded  to  the  effects  of  friction.  In  all 
these  cases,  there  seems  to  be  a  veiy  active  cir- 
culation of  blood  in  the  capillary  vessels  of  the 
bones  and  other  structures  of  the  joint.  Much 
of  the  synovial  membrane  may  be  removed 
with  the  cartilages  ;  but  the  synovial  folds  and 
fimbriae  (as  they  are  called)  which  encircle  the 
neck  of  the  radius,  and  occupy  the  different 
fossae  in  front  and  behind  the  trochlea  of  the 
humerus,  become  unusually  vascular  and  en- 
larged. 

In  most  of  the  cases  we  have  examined,  we 
have  discovered  what  are  called  foreign  bodies 
in  the  cavity  of  the  joint.  These  we  have  found 
of  all  sizes,  from  that  of  a  pea  to  that  of  a 
walnut.  Some  were  seen  hanging  into  the 
cavity  of  the  articulation,  being  suspended  by 
white  slender  membranous  threads  which 
seemed  to  be  productions  from  the  synovial 


sac;  and  some  were  loose  in  the  joint:  while,  as 
to  their  structure,  some  were  cartilaginous  and 
bony.  The  number  of  these  foreign  bodies 
we  have  seen  in  the  cavity  of  the  elbow-joint 
we  confess  has  astonished  us,  amounting  in 
one  case  to  twenty,  in  another  to  forty-five. 
In  all  these  cases  the  vessels  of  the  synovial 
fimbria;  of  the  joint  were  in  a  highly  congested 
state.  The  co-existence,  therefore,  of  foreign 
bodies  with  such  a  condition  of  the  membranes 
and  their  capillary  vessels  as  these  dissections 
elicited,  cannot  be  too  fully  impressed  on  the 
mind  of  the  practical  surgeon,  who  is  some- 
times solicited  to  undertake  an  apparently 
simple  operation  for  their  removal.  Lastly, 
instead  of  the  few  scattered  fibres  external  to 
the  synovial  sac,  which,  in  this  joint,  when  in  a 
normal  state,  can  scarcely  be  said  to  resemble 
even  the  rudiment  of  a  capsule,  we  have  found 
in  these  morbid  specimens  the  thickness  and 
number  of  ligamentous  fibres  so  considerable, 
that  the  joint  seemed  to  possess  almost  a  com- 
plete capsular  ligament. 

In  Cruveilhier's  Pathological  Anatomy,  Li- 
vraison  No.  9,  Plate  6,  Figure  1,  there  is  a  gra- 
phic delineation  of  an  elbow,  illustrating  many 
of  the  points  here  alluded  to :  he  denominates 
the  disease  usure  des  cartilages,  but  it  is  quite 
sufficient  to  look  at  one  of  these  cases,  either 
in  the  living  or  the  dead,  to  be  satisfied 
that  the  disease  does  not  confine  itself  to 
the  cartilages  of  the  joint,  but  that  the  arti- 
cular heads  of  the  bones  are  also  engaged; 
indeed,  in  many  of  our  specimens,  the  bones 
of  the  elbow-joint  are  so  much  enlarged  as  to 
resemble  at  first  sight  the  knee-joint;  the  shafts 
also  of  the  ulna  and  radius  are  heavier  and 
harder  than  natural,and  their  cancellated  struc- 
ture no  longer  exists,  the  cells  being  so  densely 
penetrated  with  phosphate  of  lime  that  the 
sections  of  these  bones  in  several  parts  present 
the  appearance  of  ivory.  This  account  of  the 
state  of  the  elbow-joint  produced  by  that  slow 
disease  called  chronic  rheumatism,  is  the  result 
of  many  observations  and  dissections  made 
specially  by  ourselves.  We  may  also  add  that 
Mr.  Smith,  the  able  curator  of  the  Museum  of 
the  Richmond  Hospital,  who  has  given  equal 
attention  to  such  investigations,  has  examined 
and  preserved  several  specimens  which  verify 
the  account  here  given  of  the  anatomical  cha- 
racters of  this  disease  ;  while,  under  the  writer's 
own  immediate  charge  in  the  House  of  Industry, 
are  numerous  living  examples  of,  and  sufferers 
from,  this  chronic  disease,  affecting  the  elbow- 
joint.  In  most  of  these  cases,  however,  some 
of  the  other  articulations  are  equally  engaged.* 
(  R.  Adams.) 

*  [Since  the  preceding  article  was  put  to  press, 
the  Editor  has  been  favoured  with  the  following 
communication  from  the  Author,  which  is  too  inte- 
resting to  be  omitted  :  '*  Within  these  three  days  I 
met  with  a  very  singular  case  of  congenital 
deformity  of  both  elbows  in  a  girl  about  eleven 
years  of  age.  The  radius  could  be  felt  to  press 
forwards  and  backwards  for  the  extent  of  an  inch 
when  it  was  rotated  either  in  pronation  or  su- 
pination. These  movements  did  not  consist  in 
a  simple  rotation  of  the  radius  on  its  longitu- 


ANIMAL  ELECTRICITY. 


81 


ELECTRICITY,  ANIMAL.— A  power, 
or  imponderable  agent,  possessed  by  and 
evolved  from  certain  living  animals,  which 
enables  them,  independently  of  the  operations 
of  external  agents  on  their  structures,  to  pro- 
duce several  of  the  phenomena  exhibited  by 
common  and  voltaic  electricity,  generated  in 
inorganic  matter. 

The  animals  so  endowed,  with  which  we  are 
at  present  acquainted,  are  all  fishes ;  and  the 
effect  by  which  their  power  is  most  sensibly 
made  known  to  us  is  the  feeling  of  a  shock,  or 
momentary  stunning,  which  is  experienced  in 
the  hand  that  touches  their  surface. 

It  is  still  doubtful  whether  the  agent  which 
produces  this  effect  be  absolutely  identical 
with  those  which  produce  the  various  pheno- 
mena of  common  and  voltaic  electricity,  ther- 
mo-electricity, &c;  but  the  most  recent  re- 
searches on  the  subject  render  it  probable  that 
it  is  the  same  in  its  nature,  although  different 
in  intensity. 

When  Galvani  discovered  the  possibility  of 
exciting  muscular  contraction  by  establishing 
an  external  communication  between  the  nerves 
and  muscles  by  means  of  metals,  he  imagined 
that  the  contraction  was  produced  by  the  sti- 
mulus of  a  peculiar  agent  (or  fluid)  existing  in 
the  nerves  in  a  state  of  accumulation,  which, 
being  attracted  by  the  metals,  passed  along 
them  to  the  external  surface  of  the  muscles. 
The  agent,  which  was  supposed  to  remain  latent 
in  the  nerves,  was  called  by  some  "  the  nervous 
fluid,"  as  it  was  imagined  to  be  identical  with 
that  power  which  animates  the  nerves  during 
life.  Galvani  seems  to  have  entertained  this 
notion.  Other  philosophers,  avoiding  a  name 
derived  from  a  theory,  denominated  the  agent 
Galvanism.    Afterwards  it  was  called  Animal 

dinal  axis,  but  a  real  change  of  place  of  the 
upper  extremity  of  the  radius  on  the  outer  con- 
dyle of  the  humerus.  The  elbow  was  but  slightly 
deformed,  and  all  its  motions  were  perfect  ex- 
cept extension,  which  was  not  complete,  but  the 
girl  had  perfect  rise  of  both  arms  and  fore-arms, 
which  were  exactly  similarly  formed.  The  ra- 
dius seemed  principally  in  fault,  and  the  motions 
of  the  upper  head  corresponded  much  to  the  de- 
scription given  of  the  subluxation.  (Vide  p.  74.) 
I  was  afforded  an  opportunity  of  examining  the 
joints  in  consequence  of  the  child  having  died  of 
scarlet  fever.  Both  joints  were  exactly  alike. 
The  radius  was  large,  the  great  sigmoid  cavity 
of  the  ulna  was  not  half  its  usual  size,  and  the 
coronoid  process  did  not  exist.  The  trochlea  on 
the  humerus,  corresponding  to  the  diminished 
sigmoid  cavity,  was  one-half  less  than  its  natural 
size  so  that  the  lower  extremity  of  the  humerus  bore 
so  striking  a  resemblance  to  the  condyles  of  the 
femur,  when  viewed  posteriorly  from  the  popli- 
teal space,  that  nobody  could  look  at  it  without 
observing  the  striking  resemblance  in  miniature 
of  the  humerus  to  the  femur.  There  were  fib  ous 
bands  representing  the  crucial  ligaments,  and  all 
the  fibres  around  were  yellow  and  stronger  than 
na  tural.  The  annular  ligament  of  the  head 
of  the  radius  was  wider  than  natural  but  much 
stronger,  and  accounted  for  the  passing  to  and 
fro  of  this  head  in  pronation  and  supination. 
That  the  deformity  was  congenital  no  one  can 
doubt  :  the  appearance — the  history  —the  exis- 
tence of  the  same  malformation  on  both  sides,  all 
prove  it."  Dec.  12,  1836'.] 
VOL.  II. 


Electricity.  These  views  were  supported  by 
Valli,  Carradori,  Aldini,  and  Fowler.  But, 
since  Volta  and  others  demonstrated  that  the 
contractions  of  the  muscles  in  Galvani's  expe- 
riments were  owing  to  electricity  developed  by 
the  contact  of  the  metals  employed,  and  not 
to  any  fluid  pre-existent  in  the  nerves,  the 
term  Animal  Electricity  has  had  its  meaning 
changed.  At  present,  most  physiologists  use 
it  in  the  sense  which  is  implied  in  the  defini- 
tion given  above. 

That  is  not  called  Animal  Electricity  which 
is  generated  by  the  friction  of  animal  sub- 
stances one  upon  the  other,  or  by  the  mere 
contact  of  animal  tissues  of  dissimilar  natures. 
The  phenomena  so  developed  have  their  source 
in  common  and  voltaic  electricity.  They  are 
phenomena  exhibited  by  animals  in  common 
with  inorganic  matter.  As  the  study  of  these, 
however,  may  ultimately  lead  to  the  elucidation 
of  some  points  connected  with  the  electricity 
of  living  fishes,  they  shall  be  noticed  in  the 
course  of  the  following  article. 

It  is  in  the  mode  of  its  development  that 
the  chief  peculiarity  of  Animal  Electricity 
consists.  None  of  the  usual  excitants  of  elec- 
tricity are  concerned  in  it.  There  is  no  che- 
mical action,  no  friction,  no  alterations  of  tem- 
perature, no  pressure,  no  change  of  form.  The 
exercise  of  the  animal's  will,  and  the  integrity 
of  the  nervous  system,  as  well  as  of  certain 
peculiar  organs  which  exist  in  all  the  animals 
endowed  with  electrical  power,  seem  to  be 
alone  sufficient  for  its  evolution. 

The  following  are  the  systematic  names  of 
the  electrical  fishes  at  present  known :  — 

Torpedo  nurke. 

  unimaculata.  llisso. 

  murmoratu.  Ditto. 

  Galvanii.  Ditto. 

Gymnolus  electricus. 

Trichiurus  electricus. 

Malapterurus  electricus. 

Tetraodon  electricus. 
The  four  species  of  Torpedo  inhabit  various 
parts  of  the  Atlantic  and  Mediterranean.  They 
were  formerly  regarded  as  constituting  one 
species,  (Raia  Torpedo,  of  Linnaeus;)  and  now 
Dr.  John  Davy  proposes  to  reduce  them  to 
two ;  having  satisfied  himself  (and  in  this  he  is 
supported  by  the  opinions  of  Cuvier  and  of 
Rudolphi)  that  the  T.  marmorata  and  T.  Gal- 
vanii are  merely  varieties  of  the  same  species, 
for  which  he  suggests  the  name  of  T.  diversi- 
color.  It  is  known  in  Italy  by  the  name  of  the 
Tremola.  The  other  species  (the  Occhiatella 
of  the  Italians)  Dr.  Davy  thinks  would  be 
better  named  T.  oculata.  Both  pass  in  Malta 
under  the  term  Haddayla.  The  first  of  these 
species  (T.  vulgaris,  of  Fleming,)  occurs  on 
the  south  coast  of  England,  where  it  some- 
times attains  a  great  size.  Pennant  mentions 
one  which  measured  four  feet  in  length  and 
two  and  a  half  in  breadth,  and  weighed  fifty- 
three  pounds.  And  Mr.  Walsh  describes  an- 
other which  was  four  feet  six  inches  in  length, 
and  of  the  weight  of  seventy-three  pounds.* 

*  Phil.  Trans.  1774. 

G 


89 


ANIMAL  ELECTRICITY. 


Both  species  (Na§xii  of  Aristotle  and  Oppian) 
are  abundant  in  some  parts  of  the  Mediter- 
ranean, and  are  frequently  brought  to  the 
market  of  Rome.  Off  the  west  coasts  of 
France,  in  Table-bay  at  the  Cape  of  Good 
Hope,  in  the  Persian  Gulf  and  in  the  Pacific 
Ocean,  the  same,  or  at  least  nearly  similar 
species  are  plentiful.  They  frequently  form  an 
article  of  food  amongst  the  poorer  class  in  the 
coast  towns  between  the  Loire  and  the  Ga- 
ronne; but  the  electrical  organs  are  carefully 
avoided,  as  they  are  supposed  to  possess  some 
poisonous  properties.  The  Gymnotus  is  found 
in  several  of  the  rivers  of  South  America ;  it 
was  met  with  by  Humboldt  in  the  Guarapiche, 
the  Oronoco,  the  Colorado,  and  the  Amazon. 
The  Malapterurus  (Silurus,  of  Linnreus)  occurs 
in  the  Niger,  the  Senegal,  and  the  Nile;  the 
Trichiurus  in  the  Indian  Seas ;  the  Tetraodon 
has  been  met  with  only  on  the  shores  of  Jo- 
hanna, one  of  the  Comoro  Isles.  According 
to  Margrav*  there  is  a  kind  of  ray-shark  on  the 
coasts  of  Brazil,  which  possesses  the  power  of 
giving  shocks.  He  described  the  fish  under 
the  name  of  Paraque.f  It  is  the  Rhinobatus 
electricus  of  Schneider  and  other  modern  ich- 
thyologists. But  in  an  examination  which 
Rudolphi  made  of  the  fish  in  question,  he 
found  no  structure  resembling  that  peculiar 
organ  which  exists  in  all  the  well-known  elec- 
trical fishes.  No  other  naturalist  has  made  the 
same  observation  as  Margrav,  so  that  the  elec- 
trical power  of  this  fish  cannot  be  regarded  as 
satisfactorily  ascertained.  In  Maxwell's  Ob- 
servations on  Congo,  mention  is  made  of  a 
large  fish  "  like  a  cod,"  possessed  of  electrical 
powers,  which  was  taken  in  the  Atlantic  Ocean. 
No  such  animal  has  yet  come  under  the  notice 
of  any  scientific  observer.  Certain  insects 
seem  to  be  possessed  of  some  power  re- 
sembling animal  electricity  in  its  effects,  but 
few  observations  have  hitherto  been  made  on 
these.  Reduvius  serratus  is  one  of  the  insects 
so  endowed  ;  with  regard  to  which  an  intel- 
ligent naturalist  reports,  that,  on  placing  a 
living  individual  on  the  palm  of  his  hand,  he 
felt  a  kind  of  shock,  which  extended  even  to 
his  shoulder;  and  that,  immediately  after- 
wards, he  perceived  on  his  hand  red  spots  at 
the  places  whereon  the  six  feet  of  the  insect 
had  rested.]:  Margrav  described  a  species  of 
Mantis,  a  native  of  Brazil,  which,  on  being 
touched,  gave  a  shock  felt  through  the  whole 
body.  According  to  the  report  of  Molina§ 
and  Vidaure,||  when  the  Sepia  hexapodia  is 
seized  with  the  naked  hand,  a  degree  of  numb- 
ness is  felt,  which  continues  for  a  few  seconds. 
Alcyonium  bursa,  a  native  of  the  German 
Ocean,  is  said  to  have  communicated  to  the 
hand  a  sensation  like  that  of  an  electrical 
shock. 

It  must  be  regarded  as  an  extremely  interest- 

*  Hist,  rerum  Nat.  Brasil.  1648. 
t  The  name  Puraqua  is  used  by  Condamine  in 
reference  to  the  Gymnotus. 

X  Kirby  and  Spence's  Entomol.  vol.  i.  110. 
6  Naturgesch.  von  Chili.  S.  175. 
jj  Gesch.  des  Kbnigr.  Chili.  S.  63. 
f  Treviranus,  Biologie.  V.  144. 


ing  fact  that  the  electric  fishes  belong  to  genera 
widely  removed,  from  one  another  in  structure 
and  habits,  and  yet  that  their  own  structure  is 
not  so  peculiar  as  to  prevent  them  from  being 
arranged  along  with  many  other  fishes  posses- 
sing no  degree  of  the  same  power  and  no 
vestige  of  a  structure  analogous  to  their  own. 

As  the  fishes  enumerated  above  have  not  all 
been  examined  with  the  same  degree  of  atten- 
tion, we  are  ignorant  of  the  extent  to  which 
they  exhibit  phenomena  exactly  resembling  one 
another.  But  it  is  well  ascertained  that  they 
all  agree  in  possessing  the  power  of  commu- 
nicating a  sudden  shock  to  the  hand  which 
touches  them.  This  shock  causes  a  certain 
degree  of  temporary  numbness  not  only  in  the 
finger  which  immediately  touches  the  fish,  but 
also  in  the  hand,  and  sometimes  even  in  the 
arm.  The  sensation  produced  has  been  com- 
pared by  different  experimenters  to  the  shock 
felt  on  the  discharge  of  a  Leyden  phial,  dif- 
fering from  it  only  in  force.  Hence  the  shock 
caused  by  an  electrical  fish  is  said  to  be  pro- 
duced by  a  discharge  of  its  electricity.  The 
numerous  facts  relating  to  the  phenomena 
which  accompany  or  are  connected  with  this 
discharge,  which  have  been  collected  by  the 
industry  of  the  many  observers  of  the  last  and 
the  present  age,  who  have  devoted  their  atten- 
tion to  the  subject,*  may  be  conveniently  ar- 
ranged under  the  following  heads:  1.  the 
circumstances  under  which  the  discharge  takes 
place  :  2.  the  motions  of  the  fish  in  the  act 
of  discharging :  3.  physiological  effects  of 
the  discharge:  4.  magnetical  effects  of  the 
discharge :  5.  chemical  effects  of  the  dis- 
charge :  6.  results  of  experiments  on  the 
transmission  of  the  discharge  through  various 
conducting  bodies :  7.  the  production  of  a 
spark  and  evolution  of  heat :  8.  results 
of  experiments  in  which  the  nerves,  electrical 
organs,  and  other  parts,  were  mutilated  :  9. 
descriptions  of  the  electrical  organs  in  the 
several  fishes  which  have  been  anatomized. 

I.  Circumstances  under  which  the  discharge 
takes  place. — Electrical  fishes  exert  their  pecu- 
liar power  only  occasionally,  at  irregular  inter- 
vals, and  chiefly  when  excited  by  the  approach 
of  some  animal,  or  by  the  irritation  of  their 
surface  by  some  foreign  body.  The  discharge, 
both  with  regard  to  time  and  intensity,  seems 
to  be  dependent  on  an  exertion  of  the  will. 
They  discharge  both  in  water  and  in  air. 
Sometimes  the  discharge  is  repeated  several 
times  in  close  succession  ;  at  other  times,  par- 
ticularly when  the  fish  is  languid,  only  one 
discharge  follows  each  irritation.  The  inten- 
sity of  the  torpedo's  discharge  is  generally 
greater  when  the  fish  is  vigorous,  becomes  gra- 
dually less  as  its  strength  fails,  and  is  wholly 
imperceptible  shortly  before  death  takes  place  ; 
but  Dr.  Davy  has  met  with  some  languid  and 
dying  fish  which  exerted  considerable  electrical 

*  Redi,  Reaumur,  Walsh,  Ingenhousz,  John 
Hunter,  Cavendish,  Bancroft,  Spallanzani,  Wil- 
liamson, Humboldt,  Gay  Lussac,  Geoffroy,  J.  T. 
Todd,  and  Dr.  John  Davy,  have  all  laboured  in 
the  same  field  of  inquiry. 


ANIMAL  ELECTRICITY. 


83 


power.  No  irritation  has  ever  produced  a  dis- 
charge after  death.  The  intensity  of  the  elec- 
trical power  seems  to  bear  no  relation  to  the 
size  of  the  fish,  at  least  after  it  has  attained 
mature  age ;  small  fish  are  almost  always  ac- 
tively electrical. 

The  torpedo  sometimes  bears  great  irritation, 
even  the  firm  grasp  of  a  hand,  without  dis- 
charging. In  these  circumstances  it  writhes 
and  twists  itself  about  for  some  time,  using 
strong  efforts  to  escape,  before  it  emits  its 
electricity.  In  a  few  instances  it  has  been 
found  impossible  by  any  means  to  excite  even 
vigorous  torpedos  to  discharge.  Both  Lace- 
pede  and  Reaumur  handled  and  irritated  the 
most  lively  torpedos,  even  while  yet  in  their 
native  element,  without  experiencing  any  shock. 
But  generally  the  shocks  are  stronger  when  the 
skin  of  the  fish  is  in  any  way  irritated.  All 
electrical  fishes  soon  become  exhausted  and 
die,  even  in  sea-water,  when  they  are  excited 
to  give  a  continued  succession  of  discharges. 
But  fishes  much  exhausted  by  frequent  dis- 
charges recover  their  electrical  energy  after  a 
few  hours'  rest.  The  torpedo  seems  to  possess 
electrical  power  even  in  the  earliest  periods  of 
its  existence.  Spallanzani  relates  that  he  found 
within  a  female  torpedo  two  living  foetuses, 
which  gave  distinct  shocks  on  being  removed 
from  their  coverings.  Dr.  Davy,  also,  once 
received  a  sharp  although  not  a  strong  shock, 
in  extracting  foetal  fish  from  the  uterine  cavities 
of  a  dying  torpedo. 

When  the  Gymnotus  is  grasped  by  the  hand, 
the  intensity  of  the  discharge  is  moderate  at 
first,  but  is  increased  if  the  pressure  be  conti- 
nued. The  torpedo  discharges  whenever  it  is 
taken  out  of  the  water ;  and  Walsh  found  that 
a  vigorous  fish  repeats  the  discharge  as  often 
as  it  is  lifted  out,  and  again  on  being  re-im- 
mersed ;  also  that  it  gives  more  violent  shocks 
in  air  than  in  water.  Spallanzani  found  the 
shock  to  be  more  severe  when  the  fish  was  laid 
on  a  plate  of  glass.  The  following  observation, 
reported  by  Walsh,  seems  to  prove  that  the 
Gymnotus  can  distinguish  at  some  distance 
between  substances  capable  of  receiving  and 
conducting  its  discharge,  and  those  which  can- 
not conduct ;  and  that  (excepting  when  it  is 
much  irritated)  it  discharges  only  when  con- 
ducting bodies  are  presented  to  it.  Two  wires 
were  put  into  the  water  of  the  vessel  in  which 
a  Gymnotus  was  swimming;  these  wires  were 
of  some  length,  and  stretched;  they  termi- 
nated in  two  glasses  filled  with  water  placed 
at  a  considerable  distance  from  each  other. 
Whilst  the  apparatus  remained  in  this  state, 
and  the  circulation  was  of  course  interrupted, 
the  animal  did  not  prepare  to  exercise  his 
power,  but  whenever  any  conducting  substance 
filled  the  interval,  and  rendered  the  circle 
complete,  it  instantly  approached  the  wires, 
arranged  itself,  and  gave  the  shock. 

The  same  fish,  according  to  the  observations 
of  Messrs.  Humboldt  and  Bonpland,  appears 
to  have  the  power  of  transmitting  its  discharge 
in  any  direction  it  pleases,  or  towards  the 
point  where  it  is  most  sharply  irritated ;  and 
further,  it  seems  to  be  able  to  discharge,  some- 


times from  a  single  point,  at  other  times  from 
the  whole  of  its  surface.  Dr.  Davy  has  s  itis- 
fied  himself  that  the  Torpedo  also  has  the 
power  of  discharging  its  electricity  in  any 
direction  it  chooses. 

The  shock  produced  by  the  discharge  of  the 
Gymnotus  is  most  severely  felt  when  one  hand 
seizes  the  head  and  the  other  the  tail.  When 
two  persons  take  hold  of  a  Gymnotus,  the  one 
by  the  head  or  by  the  middle  of  the  body,  and 
the  other  by  the  tail,  both  standing  on  the 
ground,  shocks  are  felt,  sometimes  by  one 
alone,  sometimes  by  both.  It  has  been  ob- 
served that  when  metals  are  placed  in  the 
vessel  or  pond  containing  a  Gymnotus,  the  fish 
appears  much  agitated,  and  discharges  very 
frequently. 

II.  Motions  of  the.  fish  in  the  act  of  dis- 
charging.— These  have  been  particularly  ob- 
served only  in  the  Torpedo  and  Gymnotus.  At 
the  time  of  discharging,  according  to  some  ob- 
servers, the  Torpedo  generally  becomes  some- 
what tumid  anterior  to  the  lateral  fins,  retracts 
its  eyes  within  their  orbits,  and  moves  its 
lateral  fins  in  a  convulsive  manner.  When 
the  fish  begins  to  lose  its  plumpness,  after 
having  given  frequent  shocks,  "  a  little  tran- 
sient agitation"  is  perceptible  along  the  carti- 
lages which  surround  the  electrical  organs  at 
the  time  of  the  discharge.  Dr.  Davy,  how- 
ever, states  that  he  has  never  seen  the  Torpedo 
of  the  Mediterranean  retract  its  eyes  at  the 
time  of  discharging ;  and  that  he  has  not  been 
able  to  associate  any  apparent  movement  of  the 
fish  with  the  electrical  discharge. 

The  Gymnotus  sometimes  emits  pie  strongest 
discharges  without  moving  any  part  of  its  sur- 
face in  the  slightest  perceptible  degree.  But, 
at  other  times,  it  seems  to  arrange  itself  so  as 
to  bring  the  side  of  its  body  into  a  parallel 
with  the  object  of  its  attack  before  discharging. 
When  a  small  fish  is  brought  near  a  Gymno- 
tus, it  swims  directly  up  to  it,  as  if  about  to 
seize  it ;  on  approaching  close,  however,  it 
halts,  seems  to  view  the  fish  for  a  few  seconds, 
and  then,  without  making  the  smallest  move- 
ment discoverable  by  the  eye,  emits  its  dis- 
charge ;  should  the  small  fish  not  be  killed  by 
the  first,  the  Gymnotus  gives  a  second,  and  a 
third  shock,  until  its  object  is  accomplished. 
It  continues  to  kill  a  large  number  in  close 
succession,  if  they  be  supplied  to  it,  but  it 
eats  very  few. 

III.  Physiological  effects  of  the  discharge. — 
The  effects  of  the  discharge  on  man  vary  ac- 
cording to  its  intensity  and  the  extent  of  the 
surface  of  the  fish  which  is  touched.  A  vigo- 
rous torpedo  causes  a  momentary  shock,  which 
is  felt  through  the  arm  even  as  far  as  the  shoul- 
der, and.  leaves  a  degree  of  painful  numbness 
in  the  finger  and  hand,  continuing  for  a  few 
seconds,  and  then  going  off  entirely.  Some 
observers  have  compared  the  sensation  pro- 
duced to  that  felt  in  the  arm  when  the  elbow  is 
struck  so  as  to  compress  strongly  the  ulnar 
nerve ;  and  others  (even  such  as  have  been 
much  accustomed  to  receive  electric  shocks) 
have  declared  the  sensation  to  be  extremely 
painful ;  Gay  Lussac  and  Humboldt  say  that 

G  2 


84 


ANIMAL  ELECTRICITY. 


it  is  more  so  than  the  shock  produced  by  the 
Leyden  phial ;  and  Configliachi  compares  it 
to  that  caused  by  the  contact  of  two  poles  of 
the  voltaic  pile.  Ingenhousz  thus  describes 
his  sensations  under  the  discharge  of  the  tor- 
pedo. "  I  took  a  torpedo  in  my  hand,  so  that 
my  thumbs  pressed  gently  on  the  upper  surface 
of  the  lateral  fin,  whilst  my  forefingers  pressed 
the  opposite  side.  About  one  or  two  minutes 
after  I  felt  a  sudden  trembling  in  my  thumbs, 
which  extended  no  further  than  my  hands  ; 
this  lasted  about  two  or  three  seconds.  After 
some  seconds  more,  the  same  trembling  was 
felt  again.  Sometimes  it  did  not  return  in 
several  minutes,  and  then  came  again  at  very 
different  intervals.  Sometimes  I  felt  the  trem- 
bling both  in  my  fingers  and  my  thumb.  These 
tremors  gave  me  the  same  sensations  as  if  a 
great  number  of  very  small  electrical  bottles 
were  discharged  through  my  hand  very  quickly 
one  after  the  other.  Sometimes  the  shock  was 
very  weak,  at  other  times  so  strong  that  I  was 
very  near  being  obliged  to  quit  my  hold  of  the 
animal."*  Walsh  ascertained  that  the  same 
torpedo  has  the  power  of  discharging  in  two 
different  manners,  so  as  to  produce  at  one 
time  the  effect  described  by  Ingenhousz  as  a 
trembling,  and  at  another  time  a  sharp  instan- 
taneous shock  closely  resembling  that  produced 
by  the  discharge  of  a  Leyden  phial.f  Accord- 
ing to  Sir  H.  Davy,  "  whoever  has  felt  the 
shocks  both  of  the  voltaic  battery  and  of  the 
torpedo  must  have  been  convinced,  as  far  as 
sensation  is  concerned,  of  their  strict  ana- 

logy-"t 

Sometimes  the  torpedo  buries  itself  in  the 
sand  left  dry  at  ebb-tide;  and  it  has  occasionally 
happened,  according  to  some  naturalists,  that 
persons  walking  across  the  sand,  and  treading 
upon  the  spot  beneath  which  the  electrical  fish 
lay  concealed,  have  received  his  discharge  so 
fully  as  to  be  thrown  down.§ 

The  effects  produced  by  the  discharge  of  the 
Gymnotus  are  more  severe.  When  it  is  touched 
with  one  hand,  a  smart  shock  is  generally  felt 
in  the  hand  and  fore-arm ;  and,  when  both 
hands  are  applied,  the  shock  passes  through  the 
breast.  The  discharges  of  large  fish  (they  grow 
to  the  length  of  twenty  feet  in  their  native 
rivers)  sometimes  prove  sufficient  to  deprive 

*  Phil.  Trans.  1775,  2. 
t  Phil.  Trans.  1773,  467. 
%  Phil.  Trans.  1829,  15. 

§  The  experience  of  Dr.  Davy  would  lead  us  to 
call  in  question  the  possibility  of  such  an  occurrence  ; 
for  he  has  always  found  it  necessary  to  touch  the 
opposite  surfaces  of  the  electrical  organs  or  organ  to 
receive  the  torpedo's  shock.  He  has  irritated  torpe- 
dos  very  frequently  by  pressing  with  the  finger  on 
different  parts  of  the  back,  but  however  much  the 
fish  were  irritated  he  never  had  any  sensation  re- 
ferable to  the  passage  of  the  electricity.  In  corro- 
boration of  his  opinion  that  the  fish  cannot  give  a 
shock  excepting  the  two  opposite  surfaces  of  its 
electrical  organs  be  connected  by  conductors,  Dr.D. 
states  that  when  one  surface  only  is  touched  and  irri- 
tated, the  fish  themselves  appear  to  make  an  effort 
to  bring,  by  muscular  contraction,  the  border  of  the 
other  surface  into  contact  with  the  offending  body. 
This"  is  done  even  by  fcetal  fish.  Phil.  Trans. 
1834.' 


men,  while  bathing,  of  sense  and  motion. 
Fermin  found  that  a  strong  one  had  power  to 
give  a  shock  to  fourteen  persons  at  the  same 
time  ;  and  other  experimenters  have  seen  twenty- 
seven  persons  simultaneously  receive  its  shock. 
Humboldt  states  that,  having  placed  his  feet 
on  a  fresh  Gymnotus,  he  experienced  a  more 
dreadful  shock  than  he  ever  received  from  a 
Leyden  phial,  and  that  it  left  a  severe  pain  in 
his  knees  and  in  other  parts  of  his  body,  which 
continued  for  seveial  hours.  Sometimes  the 
discharge  occasions  strong  contractions  of  the 
flexor  muscles  of  the  hand  which  grasps  the 
fish,  so  that  it  cannot  be  immediately  let  go ; 
and  then,  the  shock  being  repeated  still  more 
severely,  painful  sensations  are  experienced 
thoughout  the  whole  body,  and  headache  with 
soreness  of  the  legs  remains  for  some  time  after.* 
Paralytic  affections,  as  well  as  giddiness  and 
dimness  of  sight,  are  said  sometimes  to  have 
followed  the  reception  of  strong  discharges.f 
It  is  stated  by  some  observers  that  there  are  men 
who  are  as  insusceptible  of  the  shocks  of  electrical 
fishes  as  others  are  of  those  from  the  Leyden 
phial ;  and  that  women  affected  with  nervous 
diseases  are  seldom  conscious  of  receiving  the 
discharge.  Kaempfer  asserted}  that,  by  sup- 
pressing respiration  for  a  short  time,  any  man 
may  render  himself  insensible  to  the  torpedo's 
discharge;  but  this  has  been  disproved  by 
Walsh  and  other  observers. 

Regarding  the  effects  of  the  discharges  of  the 
other  electrical  fishes,  we  know  very  little.  The 
shock  given  by  the  Malapterurusof  the  Nile  and 
Niger  (Silurus,  Linn.)  is  said  to  be  more  feeble 
than  that  of  the  Torpedo,  and  yet  very  painful, 
attended  with  trembling,  and  followed  by 
soreness  of  the  limbs.  In  attempting  to  take  an 
individual  of  Tetraodon  electricus  in  his  hand, 
Lieutenant  Paterson  (its  discoverer)  received  so 
severe  an  electrical  shock  that  he  was  obliged  to 
quit  his  hold. 

The  effects  of  the  discharge  of  the  Gymnotus 
on  the  larger  animals  cannot  be  better  illustrated 
then  by  the  account  which  Humboldt  has  given 
of  the  method  of  capturing  the  fish  adopted  by 
the  South  American  Indians.  This  method 
consists  in  irritating  the  fish  by  driving  horses 
into  the  pools  which  it  inhabits.  It  directs 
its  electricity  in  repeated  discharges  against 
these  horses  until  it  becomes  exhausted,  when  it 
falls  an  easy  and  harmless  prey  into  the  hands  of 
the  fishermen.  Humboldt  saw  about  thirty 
wild  horses  and  mules  forced  into  a  pool  con- 
taining numerous  Gymnoti.  The  Indians  sur- 
rounded the  banks  closely,  and  being  armed 
with  harpoons  and  long  reeds,  effectually  pre- 
vented the  escape  of  the  horses.  The  fishes 
were  aroused  by  their  trampling,  and,  coming 
to  the  surface,  directed  their  electrical  discharges 
against  the  bellies  of  the  intruders.  Several 
horses  were  quickly  stunned,  and  disappeared 
beneath  the  surface  of  the  water.  Others,  ex- 
hibiting signs  of  dreadful  agony,  hurried  to  the 
bank,  with  bristled  mane  and  haggard  eye,  but 

*  Bryant,  Trans.  Amer.  Soc.  ii.  167. 
t  Flagg,  do.  ii.  170.  - 
I     X  Amoen.  Exot.  514. 


ANIMAL  ELECTRICITY. 


85 


there  they  were  met  by  the  wild  cries  and  violent 
menaces  of  the  Indians,  which  forced  them  again 
to  enter  the  water.  And  when,  at  last,  the  sur- 
vivors were  permitted  to  leave  the  pool,  they 
came  out  enfeebled  to  the  last  degree,  and  their 
benumbed  limbs  being  unable  to  support  them, 
they  stretched  themselves  out  upon  the  sand 
completely  exhausted.  In  the  course  of  five 
minutes  two  horses  were  drowned.  By  degrees, 
the  discharges  from  the  Gymnoti  becoming  less 
intense,  the  horses  no  longer  manifested  the 
same  signs  of  agony,  and  the  wearied  fishes  ap- 
proached the  margin  of  the  pool, almost  lifeless; 
and  then  they  were  easily  captured  by  means  of 
small  harpoons  attached  to  long  cords.  The 
fishes  left  in  a  pool  thus  disturbed  were  found 
scarcely  able  to  give  even  weak  shocks  at  the 
end  of  two  days  from  the  time  of  their  combat 
with  the  horses.  Humboldt  concluded  from 
what  he  saw  and  heard,  that  the  horses  which 
are  lost  in  the  course  of  this  singular  fishery  are 
not  killed,  but  merely  stunned,  by  the  dis- 
charge. Their  death  is  occasioned  by  the  con- 
sequent submersion. 

In  this  way  many  mules  are  destroyed  in  at- 
tempting to  ford  rivers  inhabited  by  the  Gymno- 
tus.  So  great  a  number  of  mules  were  thus  lost 
within  the  last  few  years  at  a  ford  near  Uritucu, 
that  the  road  by  it  was  entirely  abandoned. 
When  small  fishes  receive  the  discharge  of  a 
Gymnotus,  they  are  immediately  stunned,  turn 
upon  their  backs,  and  remain  motionless.  They 
however,  for  the  most  part,  recover  after  being 
removed  to  another  vessel.  Reaumur  reports 
that  he  once  saw  a  duck  killed  by  the  repeated 
discharges  of  a  torpedo  ;  but  both  Ingenhousz 
and  Dr.  John  Davy  kept  small  fishes  in  the  same 
vessel  with  torpedos,  without  observing  that  the 
former  showed  any  symptoms  of  suffering  from 
the  shock  of  the  latter.  Humboldt  saw  one 
Gymnotus  receive  the  discharge  of  another  with- 
out giving  any  evidence  of  feeling  it.  Galvani, 
having  placed  some  frogs' thighs,  skinned,  on  the 
back  of  a  torpedo,  saw  them  convulsed  when  the 
fish  was  excited  to  discharge. 

It  is  said  that  the  discharge  of  the  torpedo  is 
used  medicinally  by  the  Arabians  of  the  present 
day,  particularly  in  fevers.  The  patient  is  placed 
naked  on  a  table,  and  the  fish  applied  to  all  the 
members  of  the  body  in  succession,  so  that  each 
should  receive,  at  least,  one  shock.  This  treat- 
ment causes  rather  severe  suffering,  but  enjoys 
the  reputation  of  being  febrifuge. 

IV.  Magnetical  effects  of  the  discharge  — 
Schilling  asserted  that  he  had  seen  the  magnetic 
needle  set  in  motion  by  the  discharge  of  a  Gym- 
notus ;*  also,  that  the  fish  was  attracted  by  a 
magnet,  and  adhered  to  it ;  and  that  it  became 
so  languid  when  detached  from  the  magnet,  that 
it  gave  no  shock  when  irritated.  Ingenhousz, 
Spallanzani,  Flagg,  Humboldt,  and  Bonpland 
obtained  no  such  results  in  repeating  the  expe- 
riments of  Schilling.  Professor  Hahn  of  Ley- 
den  suggests  that  the  fish  examined  by  Schilling 
may  have  been  coated  with  particles  of  ferrugi- 
nous sand,  which  frequently  forms  the  beds  of 
the  American  rivers  inhabited  by  the  Gymnotus ; 

*  Mem.  de  l'Acad.  de  Berlin,  1770. 


and  that  these,  adhering  to  its  glutinous  skin, 
may  have  given  rise  to  the  phenomena  observed 
by  Schilling.  In  quoting  the  contradictory 
statements  of  the  above-mentioned  observers, 
Treviranus  remarks,*  "  it  is  a  striking  circum- 
stance that  so  good  an  observer  as  Schilling  was 
should  have  been  convinced  that  he  saw  such 
magnetic  phenomena  in  connexion  with  the  fish, 
and  still  more  remarkable  is  it  that  Humboldt 
and  Bonpland  should  have  found  a  belief  in 
the  possession  of  magnetic  properties  by  the 
Gymnotus  prevalent  amongst  the  inhabitants 
of  the  Savannas  of  Caraccas." 

Sir  Humphry  Davy  passed  many  strong  dis- 
charges from  a  torpedo  through  the  circuit  of  an 
extremely  delicate  magnetic  electrometer,  with- 
out perceiving  the  slightest  deviation  of,  or  effect 
on,  the  needle.  He  explained  this  negative 
result  by  supposing,  that  the  motion  of  the 
electricity  in  the  organ  of  the  torpedo  is  in 
no  measurable  time,  and  that  a  current  of  some 
continuance  is  necessary  to  produce  the  devia- 
tion of  the  magnetic  needle.f  Under  more 
favourable  circumstances  than  those  in  which 
Sir  H.  Davy  investigated  the  properties  of  the 
electricity  of  the  torpedo,  Dr.  John  Davy  re- 
sumed the  enquiry  at  Malta,  and  ascertained,  in 
the  most  satisfactory  manner,  that  animal  elec- 
tricity is  capable  of  producing  magnetic  effects. 
He  not  only  saw  the  needle  of  a  magnetic  elec- 
trometer very  much  affected  by  the  discharge  of 
a  torpedo,  but  he  found  needles,  previously  free 
from  magnetism,  converted  into  magnets  by  the 
same.  In  one  experiment,  he  placed  eight 
needles  within  a  spiral,  formed  of  fine  copper 
wire,  one  inch  and  a  half  long,  and  one  tenth  of 
an  inch  in  diameter,  containingaboutonehundred 
and  eighty  convolutions, and  weighingfour  grains 
and  a  half.  A  single  discharge  from  a  torpedo, 
six  inches  long,  having  been  passed  through 
this,  the  contained  needles  were  all  converted 
into  magnets,  each  one  as  strong  as  if  only  one 
had  been  used.  It  was  found  that  the  ends  of 
the  needles  which  were  nearest  the  ventral  sur- 
face of  the  fish  had  received  southern  polarity, 
and  of  course  the  other  extremities  northern  po- 
larity. The  discharges  from  fish,  only  four  hours 
after  they  were  taken  from  the  uterine  cavities  of 
their  mother,  were  sufficiently  strong  to  magne- 
tize needles  through  the  medium  of  a  spiral,  al- 
though but  feebly.  The  same  kind  of  result  was 
obtained  with  the  multiplier;  the  needle  of 
which,  when  subjected  to  a  torpedo's  discharge, 
indicated  that  the  electricity  of  the  dorsal  surface 
corresponded  with  that  of  the  copperplate  of 
the  voltaic  pile,  and  the  electricity  of  the  ventral 
surface  with  that  of  the  zinc  plate. 

In  1827,  before  Dr.  Davy  performed  his  ex- 
periments, similar  magnetic  effects  were  observed 
by  means  of  the  multiplier,  by  MM.  De 
Blainville  and  Fleuriau,  at  La  Rochelle.  They 

*  Biologie,  v.  145. 

t  Phil.  Trans.  1829.  16.  Similar  experiments 
were  made  with  the  discharge  of  the  Gymnotus  by 
Messrs.  Rittenhouse  and  Kinnersly  with  the  same 
results.  They  saw  no  effect  produced  on  the  elec- 
trometer. Philadelphia  Med .  and  Phys.  Journal, 
i.  15. 


86 


ANIMAL  ELECTRICITY. 


thrust  into  the  electrical  organ  of  a  torpedo 
the  two  needles  which  terminate  the  wires  of 
Schweigger's  multiplier,  and  immediately  saw 
the  magnetic  needle  describe  more  than  half  a 
revolution.* 

V.  Chemical  effects  of  the  discharge. — It 
does  not  appear  that  any  observer  before  Sir 
H.  Davy  attempted  to  ascertain  what  chemical 
effects  the  discharge  from  electrical  fishes  is 
capable  of  producing.  But  Sir  Humphry 
obtained  only  negative  results.  He  passed  the 
shocks  of  the  torpedo  through  the  unterrupted 
circuit  made  by  the  silver  wire  through  water, 
without  being  able  to  perceive  the  slightest  de- 
composition of  the  water.f  Dr.  John  Davy, 
however,  has  obtained  decisive  evidence  of 
chemical  agency  being  exerted  by  animal  elec- 
tricity. The  fishes  which  he  made  use  of  in 
his  experiments  were  more  recently  taken  from 
the  sea,  and  were,  consequently,  more  vigorous 
than  those  which  were  the  subjects  of  Sir 
Humphry's  observations;  and  it  was,  probably, 
owing  to  this  circumstance  that  the  results  which 
he  obtained  were  different  from  those  of  his 
brother's  experiments. 

By  means  of  golden  wires,  one  of  which  was 
applied  to  the  upper  surface  of  the  fish,  and  the 
other  to  its  under  surface,  Dr.  Davy  passed  the 
discharge  from  a  torpedo  through  solutions  of 
nitrate  of  silver,  common  salt,  and  superacetate 
of  lead,  and  found  that  all  were  decomposed. 
The  decomposition  of  the  superacetate  of  lead 
was  effected  only  when  the  fish  seemed  to  put 
forth  all  its  energy,  after  being  much  irritated. J 
From  the  solution  of  nitrate  of  silver,  the  metal 
was  precipitated  only  on  the  wire  connected 
with  the  ventral  surface  of  the  fish.  When 
platina  wires  were  used,  and  plunged  into  nitric 
acid,  gas  was  given  off  only  from  that  in  con- 
nexion with  the  dorsal  surface.  A  solution  of 
iodide  of  potassium  and  starch  having  been 
subjected  to  the  discharge  conveyed  along  the 
platma  wires,  had  the  iodine  in  combination 
with  the  starch  precipitated  from  it  on  the  wire 
from  the  upper  surface.§  By  the  same  dis- 
charges which  produced  these  chemical  effects, 
the  needle  in  the  galvanometer  was  moved,  the 
spirit  in  the  air-thermometer  was  raised,  and 
needles  in  the  spiral  were  magnetized. 

VI.  Results  of  experiments  on  the  transmis- 
sion of  the  discharge  through  various  conduct- 
ing bodies. — Almost  all  bodies  which  are  con- 
ductors of  common  and  voltaic  electricity  con- 
duct also  the  discharge  of  electrical  fishes ;  and 
those  which  are  non-conductors  with  regard  to 
the  former  are  the  same  with  regard  to  the  latter. 
But  the  discharge  of  the  torpedo,  when  feeble, 
does  not  pass  along  even  good  conductors  ;  and 
this  circumstance  has  given  rise  to  some  dis- 
crepancy between  the  statements  of  different 
observers.  Walsh  received  the  torpedo's  dis- 
charge through  iron  bolts  and  wet  hempen 
cords.  The  French  fishermen  declare  that  they 
sometimes  receive  shocks  through  nets,  while 

*  Pouillet,  Plem.  de  Phys.  i.  773. 
t  Phil.  Trans.  1829. 
t  Phil.  Trans.  1832. 
§  Phil.  Trans.  1834. 


the  fish  is  twelve  feet  distant  from  their  hands. 
But  Humboldt  and  Gay  Lussac  state  that  they 
received  no  shock  when  they  touched  the  fish 
with  a  key  or  any  other  conducting  body;* 
further,  that  when  they  placed  the  fish  upon  a 
metallic  plate,  so  that  the  inferior  surface  of  its 
electric  organ  touched  the  metal,  the  hand  which 
supported  it  felt  no  shock  :  and  they  concluded 
from  their  experiments  that  the  torpedo  could 
not  transmit  its  discharge  through  even  a  thin 
layer  of  water  ;  although  they  found  that  when, 
two  persons  applied  each  one  hand  to  the  fish, 
and  completed  a  circuit  through  their  own 
bodies  by  means  of  a  pointed  piece  of  metal 
held  in  the  other  hand,  and  plunged  into  a  little 
water  placed  upon  an  insulating  body,  both 
felt  the  shock.  In  one  instance  Dr.  Davy 
received  the  torpedo's  shock  through  water,  but 
his  hand  was  within  a  very  short  distance  of  the 
fish.  Walsh  transmitted  the  torpedo's  discharge 
through  a  chain  of  eight  persons,  who  com- 
municated with  one  another  only  by  water  con- 
tained in  basins,  in  which  their  hands  were 
immersed.  And  the  same  observer  also  found 
that  when  a  torpedo  was  touched  with  a  single 
finger  of  one  hand,  while  the  other  hand  was 
held  in  the  water  at  some  distance,  shocks 
were  distinctly  felt  in  both  hands.  Numerous 
observations  made  on  the  Gymnotus  leave  no 
doubt  with  regard  to  the  passage  of  its  discharge 
through  water.  If  a  person  hold  his  finger  in 
the  water  several  inches  (some  say  even  ten 
feet)  distant  from  the  fish,  and  another  person 
touch  it,  both  receive  shocks  equally  severe. 
Dr.  Williamson  found  that  a  person  holding  his 
finger  in  a  stream  of  water,  running  from  a  hole 
made  in  the  bottom  of  a  wooden  vessel  in 
which  a  Gymnotus  was  swimming,  very  dis- 
tinctly felt  all  the  discharges  given  by  the  fish. 
The  discharge  from  the  Gymnotus  passes  through 
a  chain  of  ten  persons,  so  that  they  all  seem  to 
feel  the  shock  in  the  same  degree.  It  is  con- 
ducted by  iron  rods  several  feet  in  length.  It 
does  not  pass  through  air,  interposed  between 
metallic  conductors,  until  these  are  brought 
within  about  one-hundredth  of  an  inch  of  each 
other. 

So  far  as  they  have  been  examined,  the  phe- 
nomena presented  by  the  discharge  of  the 
Silurus  have  been  found  to  be  nearly  the  same 
as  those  just  detailed. 

VII.  The  production  of  a  spark,  and  evolu- 
tion of  heat. — No  observer  has  hitherto  seen  light 
emitted  from  the  body  of  any  electrical  fish  at 
the  time  of  the  discharge ;  but,  by  artificial 
arrangements,  some  have  succeeded  in  pro- 
ducing sparks  in  the  course  of  the  circuit  de- 
scribed by  the  discharge.  In  1792,  Gardini 
saw  a  spark  from  a  torpedo's  discharge,  in 
the  course  of  his  repeating  some  of  Walsh's 
experiments.  And  in  1797,  Galvani  obtained 
a  small  spark,  visible  only  with  the  aid  of  a 
lens,  from  a  torpedo  ;  but  it  does  not  appear  that 
any  other  observer  has  been  equally  successful 
with  regard  to  this  fish.  Very  recently,  Dr.  Davy 
has  directed  his  attention  particularly  to  this 
point,  and,  although  he  used  active  fish,  and  took 

*  Ann.  de  Chimie,  t.  lxv.  15. 


ANIMAL  ELECTRICITY. 


87 


every  possible  precaution,  he  could  neither,  in 
the  light,  detect  the  slightest  indications  of  the 
passage  of  electricity  through  even  very  small 
intervals  of  air,  nor  observe  a  spark  in  the  dark. 
He  was  equally  unsuccessful  in  using  an  elec- 
troscope formed  on  the  principle  of  Coulomb's, 
which  displayed  sparks  when  touched  either 
with  a  small  rod  of  glass  slightly  excited,  or  of 
sealing-wax.  He  varied  the  trials,  using  highly 
rarefied  air  at  ordinary  temperatures,  and  also 
condensed  air  deprived  of  moisture,  with  the 
same  negative  result.  He  insulated  the  fish  on 
a  plate  of  glass,  wiped  its  margin  dry,  and 
besmeared  it  with  oil,  but  no  spark  could  be 
procured. 

Dr.  Davy  was  more  successful  in  obtaining 
indications  of  the  evolution  of  heat  during  the 
torpedo's  discharge.  He  used  Harris's  electro- 
meter, and  saw  proof  of  an  elevation  of  tem- 
perature in  the  motions  of  the  fluid  in  the  air- 
thermometer;  thus  corroborating  the  prediction 
of  Dr.  Faraday,  who  was  previously  convinced 
that,  by  means  of  this  instrument,  the  evolution 
of  heat  by  animal  electricity  would  be  made 
evident.  Dr.  Davy  made  several  experiments 
with  the  view  of  ascertaining  whether  very  fine 
platina  wire  might  not  be  ignited  in  the  passage 
of  the  electricity  of  the  torpedo,  but  never 
witnessed  the  expected  effect.  Upon  this  he 
remarks,  "This  want  of  ignition  may,  at  first 
view,  seem  contrary  to  the  effect  on  the  ther- 
mometer ;  but  perhaps  it  ought  not  to  be  con- 
sidered so,  taking  into  account  the  rapid  man- 
ner in  which  the  heat  evolved  in  the  fine  pla- 
tina wire  must  be  carried  off  by  the  adjoining 
compound  wire  of  platina  and  silver."* 

From  the  discharge  of  the  Gymnotus,  Walsh, 
Fahlberg,  Guisan,  and  other  observers  of  the 
last  century,  obtained  sparks.  Walsh  attached 
a  thin  sheet  of  pewter  to  a  plate  of  glass,  cut  a 
very  fine  slit  in  it,  and  then  passed  the  discharge 
along  the  metallic  sheet,  the  fish  being  at  the 
time  out  of  the  water.  A  spark  was  very  dis- 
tinctly seen  at  the  margins  of  the  slit.  Fahlberg 
of  Stockholm  used  the  same  kind  of  apparatus, 
but  with  gold  leaves  instead  of  pewter,  and 
placed  the  margins  of  these  about  a  line  apart. 
Dr.  Williamson  fixed  two  brass  rods  in  a  frame, 
and  brought  their  points  to  within  one-hundredth 
of  an  inch  of  each  other,  but,  although  the  dis- 
charge of  the  gymnotus  passed  from  one  rod  to 
the  other  through  the  intervening  air,  there  was 
no  spark.  Humboldt  watched  an  active  Gym- 
notus for  a  long  time  during  the  night,  and 
irritated  it  so  as  to  obtain  from  it  many  sharp 
discharges,  but  he  saw  no  spark. 

VIII.  Results  of  experiments  in  which  the 
nerves,  electrical  organs,  and  other  parts  were 
mutilated. — The  general  result  of  these  experi- 
ments is,  that  destruction  of  the  communications 
between  the  electrical  organs  and  the  nervous 
centres  is  followed  by  annihilation  of  the  power 
of  discharging. 

According  to  Mr.  Todd,  (whose  experiments 
were  made  on  the  torpedo  at  the  Cape  of  Good 
Hope,)  it  is  necessary  to  cut  through  all  the 
nerves  going  to  the  electrical  organs  to  destroy 

*  Phil.  Trans.  1834. 


their  peculiar  powers.  He  cut  through  all  on 
one  side,  and  some  on  the  other,  but  still 
shocks  were  given.  He  also  lacerated  the 
organs  themselves  extensively,  without  destroy- 
ing the  discharging  power.  Mr.  Todd  found 
that  fishes  in  which  all  the  electrical  nerves  had 
been  cut  appeared  more  vivacious  after  the 
operation  than  before  it,  and  actually  lived 
longer  than  others  not  so  injured,  but  which 
were  excited  to  discharge  frequently.* 

In  repeating  Mr.  Todd's  experiments,  Dr. 
Davy  obtained  very  similar  results;  but  he 
mentions  that  "when  a  small  portion  of  brain 
was  accidentally  left,  contiguous  to  the  elec- 
trical nerves  of  one  side,  and  with  which  they 
were  connected,  the  fish,  on  being  irritated, 
gave  a  shock  to  an  assistant,  who  grasped  the 
corresponding  electrical  organ. "f 

Spallanzani  found  that  the  torpedo  loses  its 
power  of  giving  shocks  after  the  aponeurotic 
covering  of  the  electrical  organs  is  removed ; 
but  that  the  cutting  out  of  the  heart  does  not 
lessen  this  power  until  the  animal  life  begins  to 
suffer  from  the  loss  of  blood. 

Humboldt  cut  a  Gymnotus  through  the  mid- 
dle of  the  body  transversely,  and  found  that  the 
anterior  portion  alone  continued  to  give  shocks. 

Experiments  of  this  kind  have  not  yet  been 
performed  on  the  Silurus ;  but,  judging  from 
the  structure  of  the  organs  in  this  fish,  we  have 
every  reason  to  expect  that  the  results  of  such 
experiments  on  it  would  be  the  same.  While 
we  would  not  be  understood  to  sanction  the 
wanton  repetition  of  experiments  such  as  these, 
which  cannot  but  be  productive  of  much  suffer- 
ing to  the  subjects  of  them,  we  must  yet  repeat 
here  the  suggestion  recently  made  by  Professor 
Muller  of  Berlin  with  regard  to  future  experi- 
ments on  the  Gymnotus  and  Silurus.  He  points 
out  how  very  desirable  it  is  to  ascertain  whether 
the  double  organs  of  these  fishes  act  as  opposite 
electromotors,  which  might  be  determined  by 
cutting  out  one  organ  from  either  side,  and  then 
exciting  the  fish  to  discharge.  The  same  dis- 
tinguished physiologist  remarks  that  if  he  had 
an  opportunity  of  experimenting  on  the  torpedo, 
his  first  experiment  should  be,  after  having  cut 
through  the  nerves  going  to  the  electrical  organs, 
to  irritate  their  cut  extremities,  still  in  connexion 
with  the  organs,  with  mechanical  and  galvanic 
stimulants,  with  the  view  of  discovering  whether 
these  would  excite  the  organs  to  discharge  their 
electricity.^ 

IX.  Anatomy  of  the  electrical  organs. — The 
experiments  referred  to  in  the  former  section 
sufficiently  demonstrate  that  the  manifestation 
of  the  peculiar  power  possessed  by  electrical 
fishes  depends  on  the  integrity  of  the  connexion 
between  their  nervous  centres  and  certain 
organs  of  a  peculiar  structure,  which  have 
been  named  the  electrical  organs.  These  have 
been  particularly  examined  in  the  Torpedo, 
Gymnotus,  and  Silurus,  by  several  anatomists, 
and  no  doubt  is  entertained  that  they,  together 

*  Phil.  Trans.  1816. 

f  Phil.  Trans.  1834.  120. 

I  Handbuch  der  Physiol,  des  Menschen.  Co- 
blenz.  1833. 


38 


ANIMAL  ELECTRICITY. 


with  their  large  nerves,  are  the  sole  means  coverings  are  discovered  investing  the  electrical 

employed  in  bringing  this  mysterious  agent  organs.    The  outer  one  has  longitudinal  fibres, 

under  the  control  of  the  animal's  volition,  which  are  rather  loosely  adherent,  and,  around 

They  are  therefore  well  worthy  of  an  attentive  the  margins  of  the  organs,  seem  to  inosculate 

examination.  with  the  skin.    The  inner  fascia  is  of  consider- 

1.  The  electrical  organs  in  the  torpedo. —  able  density,  forms  the  immediate  tunic  of  the 

The  torpedo  is  a  flat  fish,  possessing  the  same  electric  columns,  and  sends  processes  down 

general  appearance  and  structure  as  the  rays,  between  them  to  form  their  partitions.  Through- 

and  classed  along  with  them  in  zoological  sys-  out  their  whole  extent,  the  essential  part  of  the 

terns.    The  electrical  organs  occupy  a  large  electrical  organs  is  formed  by  a  whitish  soft 

Fig.  47. 


Upper  surface  of  electrical  organ  of  left  side. 

A,  common  integuments.  B,  hranchial  opening.  C,  eye.  D,  situation  of  the  gills.  E  E,  skin  dis- 
sected off  from  the  electrical  organ,  and  turned  outwards.  F,  part  of  the  skin  which  covered  the  gills, 
G  G,  the  upper  surface  of  electrical  organ. 


part  of  the  broad  expansions  of  the  body, 
which  in  the  other  allied  fishes  are  formed 
only  by  the  lateral  fins.  They  form  two  sepa- 
rate masses,  one  on  either  side  of  the  head  and 
gills,  extending  outwardly  to  the  cartilaginous 
margins  of  the  great  fins;  and,  posteriorly,  to 
the  cartilage  which  separates  the  thoracic  from 
the  al  dorainal  cavity.  Their  form  and  the 
honey-comb  embossments  of  their  surfaces  can 
be  distinguished  through  the  skin  both  of  the 
dorsal  and  ventral  aspects.  The  common  inte- 
guments being  removed,   two  strong  fascial 


pulp,  divided  into  numerous  pentagonal  prisms 
by  the  fascial  processes  just  mentioned.  These 
lie  close  together,  parallel  with  one  another, 
and  perpendicularly  between  the  dorsal  and 
ventral  surfaces  of  the  fish,  so  that  their  extre- 
mities are  separated  from  these  surfaces  only 
by  their  fascial  and  the  common  integuments. 
YVhen  these  are  removed,  the  columns  present 
something  of  the  appearance  of  a  honey-comb. 
The  columns  are  longest  next  to  the  head  and 
gills,  and  thence  gra  lually  diminish  outwardly, 
until,  on  the  external  margin,  they  are  only 


ANIMAL  ELECTRICITY. 


89 


about  one-sixth  of  the  length  of  the  internal 
ones.  In  a  fish  described  by  John  Hunter,* 
of  which  the  whole  electrical  organ  was  about 
five  inches  in  length,  the  longest  column  was 
about  one  inch  and  a  half,  and  the  shortest 
about  one-fourth  of  an  inch  in  length.  In  the 
same  fish  the  average  diameter  of  each  column 
was  about  two-tenths  of  an  inch.  In  a  fish 
from  the  Mediterranean,  thirteen  inches  and  a 
half  in  length,  and  about  seven  inches  in 
breadth,  (which,  through  the  kindness  of  Dr. 
Allen  Thomson,  we  have  had  an  opportunity 
of  examining  in  detail,)  the  length  of  the 
longest  columns  is  one  inch,  and  that  of  the 
shortest  about  three-tenths  of  an  inch.  Most 
of  these  columns  are  either  irregular  pentagons, 
or  irregular  hexagons ;  a  few  are  nearly  tetra- 
gonal. They  are  united  to  one  another  by 
short  but  strong  fibres,  and  by  a  reticular 
expansion  of  tendinous  threads  spread  through 
them.  Their  number  varies  considerably  ac- 
cording to  the  age  of  the  fish.  Hunter  con- 
jectured that  a  few  new  columns  are  added 
every  year  to  the  circumference  of  the  organ. 
In  one  of  the  largest  fish  that  has  yet  been 
particularly  examined,  which  was  four  feet  and 
a  half  in  length,  the  number  of  columns  in 
one  electrical  organ  was  1182.  Mr.  Hunter 
found  470  in  each  organ  in  a  fish  of  ordinary 
size.  Mr.  Hunter  described  each  column  as 
being  divided  into  numerous  distinct  compart- 
ments by  delicate  membranous  partitions, 
placed  horizontally,  at  very  short  distances 
from  each  other.  The  interstices  between  them 
appeared  to  him  to  contain  a  fluid.  He  found 
the  partitions  in  several  places  adhering  to  one 
another  by  bloodvessels;  and  all,  throughout 
their  whole  extent,  attached  to  the  inside  of 
the  column  by  a  fine  cellular  membrane.  In 
a  column  of  one  inch  in  length,  he  reckoned 
150  partitions,  and  it  appeared  to  him  that 
their  number  is  the  same  within  the  same  space 
in  all  the  columns.f  Hence,  he  thought  it 
likely  that  "  the  increase  in  the  length  of  a 
column,  during  the  growth  of  the  animal,  does 
not  enlarge  the  distance  between  each  partition 
in  proportion  to  that  growth,  but  that  new 
partitions  are  formed  and  added  to  the  extre- 
mity of  the  column  from  the  fascia." 

The  partitions  are  covered  with  fine  network 
of  arteries,  veins,  and  nerves.  According  to 
Hunter,  "  they  are  very  vascular."  He  described 
the  numerous  arterial  branches  which  ramify 
on  the  walls  of  the  columns  as  "  sending  in- 
wards from  the  circumference  all  around,  on 
each  partition,  small  arteries  which  anastomose 
upon  it,  and  passing  also  from  one  to  the  other, 
unite  with  the  vessels  of  the  adjacent  parti- 
tions." The  partitions  themselves  are  so  deli- 
cate as  not  to  admit  of  being  satisfactorily 
examined  in  the  fresh  fish  :  (all  Hunter's  obser- 
vations were  made  upon  fish  that  had  been 
preserved  in  spirits,  by  which,  doubtless,  the 
delicate  membranes  were  rendered  more  opaque, 
and  therefore  more  easily  visible.)    In  point 

*  Pl.il.  Trans  1773,  481. 

t  Desmotilins  and  Majenriie  say  that  they  found 
only  seven  or  eight  partitions  in  each  column. 
Anat.  des  Syst.  Nerv.  ii.  378. 


of  fact,  Dr.  Davy  has  never  seen  them  in  the 
course  of  the  numerous  dissections  which  he 
has  made  of  the  electrical  organs  in  fish  recently 
taken;  whereas,  in  specimens  sent  hither  by 
him,  preserved  in  spirits,  Dr.  Allen  Thomson 
and  the  writer  of  this  article  have  satisfactorily 
ascertained  their  existence  and  structure  as 
described  by  Hunter.  Dr.  Davy  says,  "  when 
I  have  examined  with  a  single  lens,  which 
magnifies  more  than  200  times,  a  column  of 
the  electrical  organs,  it  has  not  exhibited  any 
regular  structure ;  it  has  appeared  as  a  homo- 
geneous mass,  with  a  few  fibres  passing  into  it 
in  irregular  directions,  which  were  probably 
nervous  fibres."*  However,  after  having  im- 
mersed the  organs  in  boiling  water,  Dr.  Davy 
has  occasionally  seen  something  like  a  lami- 
nated structure  within  the  column.  Rudolphi 
satisfied  himself  of  the  division  of  the  columns 
by  membranous  partitions,  and  further,  that 
each  partition  is  supplied  with  a  distinct  nerve.-f- 
In  a  memoir  on  the  comparative  anatomy  of 
the  Torpedo,  Gymnotus,  and  Silurus,  Geoff'roy 
described!  the  columns  as  being  filled  with  a 
semifluid  matter  composed  of  gelatine  and 
albumen. 

A  lar«e  quantity  of  fluid  enters  into  the 
composition  of  the  general  mass  of  the  elec- 
trical organs.  Dr.  Davy  has  found  that  they 
lose  more  by  drying  than  any  other  part  of  the 
fish — nearly  93  per  cent.;  while  the  soft  parts 
in  general,  including  the  electrical  organs,  lose 
only  84.5  per  cent,§  He  believes  that  the  fluids 
of  the  organs  hold  various  substances  in  solution, 
but  the  exact  nature  and  proportions  of  them 
have  not  been  ascertained.  We  are  indebted 
to  the  same  indefatigable  observer  for  an  ac- 
count of  the  specific  gravity  of  the  electrical 
organs.  He  found  it  to  be  very  low  compared 
with  that  of  the  truly  muscular  parts  of  the 
fish, — namely,  1.020,  to  water  as  1.0G0,  while 
that  of  a  part  of  the  abdominal  muscles  of  the 
same  full-grown  fish  was  1.058,  and  of  the 
dorsal  muscles  1.065.  In  a  fish  eight  inches 
long,  five  inches  across  the  widest  part,  and 
which  weighed  2065  grains  entire,  the  electric 
organs  together  weighed  302  grains,  the  liver 
only  105  grains. 

No  contraction  has  ever  been  seen  in  the 
electrical  organs  of  living  fish  under  the  stimu- 
lus of  the  strongest  excitants,  not  even  under 
that  of  galvanism ;  so  that,  although  what 
appear  to  be  tendinous  threads  are  spread 
amongst  and  over  the  columns,  we  have  no 
reason  to  suppose  that  any  muscular  tissue 
enters  into  their  composition.  But,  in  all 
directions,  they  are  exposed  to  the  pressure  of 

*  Phil.  Trans.  1832.  259. 

t  Ahhandl.  der  Acad,  der  Wissensch.  in  Berlin. 
1820.  224. 

t  Ann.  dn  Mus.  TvTo.  5. 

§  The  sma'lest  torpedo  employed  hy  Dr.  Davy 
in  his  experiments  weighed  410  grains,  and  con- 
tained only  48  grains  of  solid  matter;  its  elec- 
trical organs  weighed  150  grains,  and  contained 
only  14  grains  of  solid  matter;  yet  this  small  mass 
gave  sharp  shocks,  converted  needles  into  magnets, 
affected  distinctly  the  multiplier,  and  acted  as  a 
chemical  agent.  "  A  priori,  how  inconceivable 
that  these  effects  could  be  so  produced'." 


00 


ANIMAL  ELECTRICITY. 


strong  muscles,  such  as  are  plainly  designed  to 
compress  them.  Some  of  these  are  inserted  into 
the  marginal  cartilages  of  the  fins;  and  there  is  a 
set  of  very  powerful  ones,  arranged  in  a  cruci- 
form manner  on  the  ventral  surface,  so  placed 
as  to  compress  the  electrical  organs  most  strongly 
during  their  contraction.  Dr.  Davy  remarks, 
"  It  is  only  necessary  to  compare  these  muscles 
as  they  exist  in  the  torpedo  with  the  same  in 
any  other  species  of  ray  to  be  convinced  that 
they  are  adequate  to,  and  designed  for,  the 
compression  of  the  batteries." 

Some  observers,  as  John  Hunter,  state  that  a 
large  proportion  of  blood  circulates  through  the 
electrical  organs.  Girardi  found  the  torpedo 
much  more  full  of  blood  than  the  other  rays.* 
But  Dr.  Davy  says,  that  there  are  very  few 
vessels  containing  red  blood  in  the  organs  them- 
selves; although  their  tegumentary  coverings 
and  the  adjoining  mucous  system  are  highly 
vascular.  The  arteries  of  the  organs  are 
branches  from  the  arteries  of  the  gills  ;  their 
veins  run  between  the  gills  direct  to  the  auricle. 
The  temperature  of  the  electrical  organs  is  not 
at  all  higher  than  that  of  other  parts  of  the  fish. 

All  anatomists  who  have  examined  the  torpedo 
have  had  their  attention  much  arrested  by  the 
great  size  of  the  nerves  distributed  to  the  electri- 
cal organs.  These  consist  of  three  principal 
trunks,  all  arising  immediately  from  the  cerebro- 
spinal system.  The  two  anterior  trunks  are  re- 
garded by  Desmoulins  and  Majendie  f  as 
portions  of  the  fifth  pair  of  nerves,  and  the  third 
as  a  branch  of  the  eighth  pair.  But  the  first 
electrical  nerve  seems  to  have  an  origin  altogether 
distinct  from  the  root  of  what  is  unquestionably 
the  main  portion  of  the  fifth  pair,  although  it 
certainly  is  in  very  close  proximity  with  it,  and, 
in  passing  out  of  the  cranium,  the  two  nerves 
seem  to  be  in  some  degree  united  for  a  short 
space.  Immediately  beyond  this  point  of  union, 
the  electrical  nerve  sends  a  soft  twig  to  a  small 
cavity  within  the  adjoining  cartilage,  (which  Dr. 
Davy  thinks  is  the  ear,)  and  then  divides  into 
three  small  branches,  and  two  large  ones.  One 
of  the  small  branches  goes  to  the  gills,  another 
to  the  neighbouring  muscles,  and  the  third  to 
the  mouth.  The  first  of  the  large  branches  runs 
along  the  outer  margin  of  the  electrical  organ, 
advancing  first  anteriorly,  then  going  round  to 
the  posterior  part  of  its  circumference,  and 
losing  itself  in  the  mucous  glands  of  the  tegu- 
mentary system,  without  sending  a  single  twig 
into  the  electrical  organ  itself.  The  other  great 
branch  is  inferior  to  the  former  in  position,  but 
much  more  voluminous  ;  it  enters  the  electrical 
organ,  and  is  ramified  through  its  anterior  third 
part,  passing  between  its  columns,  and  giving 
off  numerous  twigs  for  the  supply  of  the  walls  of 
the  columns,  and  the  partitions,  on  which  it 
terminates;  some  of  which  pass  even  into  the 
gelatinous  matter  with  which  the  columns  are 
filled.  This  branch,  from  its  very  origin,  has 
all  its  fibres  separated,  isolated,  and  parallel, 
held  together  only  by  cellular  tissue,  which 
also  forms  a  kind  of  membranous  sheath  around 

*  Mem.  della  Soc.  Ital.  iii.  553. 
t  Anat.  Comp.  des  Syst,  nerv. 


the  nerve.  Just  as  it  reaches  the  organ,  it  is 
divided  horizontally  into  two  portions,  one  of 
which  runs  near  the  upper  surface,  the  other  on 
the  plane  between  the  lower  and  middle  thirds 
of  the  thickness  of  the  organ. 

When  examined  with  a  high  magnifying 
power,  the  minute  branches  of  the  electrical 
nerves  present  a  dotted  appearance,  showing  as 
if  the  medullary  substance  were  arranged  within 
the  sheath,  not  in  a  continuous  line,  but  in  a 
succession  of  small  portions  with  a  little  space 
between  each.* 

The  second  electrical  nerve  rises  a  little  be- 
hind the  former.  After  leaving  the  cranium,  it 
divides  into  two  large  branches,  which,  with  the 
exception  of  a  few  twigs  which  go  to  the  gills, 
are  wholly  distributed  in  the  middle  third  of 
the  electrical  organs,  in  the  same  manner  as  the 
first  pair. 

The  third  electrical  nerve  arises'from  the  brain 
close  to  the  second,  from  which,  however,  it  is 
separated  by  a  thin  cartilaginous  plate.  The 
greater  portion  of  it  goes  to  the  electrical  organ, 
and  is  distributed  through  its  posterior  third.  It 
also  supplies  part  of  the  gills,  the  gullet,  the  sto- 
mach, and  the  tail.  Dr.  Davy  says  it  appeared 
to  him  that  the  branch  of  this  nerve  which  goes 
to  the  stomach  is  the  principal  nerve  of  that 
organ  :  it  is  spread  over  its  great  arch.f  The 
same  observer  also  points  out  as  deserving  of 
particular  attention,  a  very  large  plexus  of  nerves 
formed  by  a  union  of  the  anterior  and  posterior 
cervical  nerves,  of  the  former  of  which  there  are 
seventeen  on  either  side,  and  only  fourteen  of 
the  latter.  This  plexus  presents  itself  as  a 
single  trunk  just  below  the  transverse  cartilage 
that  divides  the  thoracic  from  the  abdominal 
cavity.  It  sends  a  recurrent  branch  to  the 
muscles  and  skin  of  the  under  surface  of  the 
thorax;  but  the  larger  portion  is  distributed 
upon  the  pectoral  fin  and  the  neighbouring 
parts.  The  motive  and  sentient  powers  of  the 
muscles  and  integuments  connected  with  the 
electrical  organs  seem  to  depend  on  this 
plexus. 

The  only  other  peculiarity  of  structure  in  the 
torpedo  which  can  be  supposed  to  be  in  any 
way  connected  with  its  electrical  power,  is  in 
the  system  of  mucous  ducts,  which  is  much 
more  fully  developed  in  it  than  in  any  other  ray 
with  which  we  are  acquainted.  It  consists  of 
numerous  groups  of  glands  arranged  chiefly 
around  the  electrical  organs;  and  of  tubes  con- 
nected with  these,  having  strong  and  dense 
coats,  filled  with  a  thick  mucus  secreted  by  the 
glands.  The  tubes  open  chiefly  on  the  dorsal 
surface  of  the  skin,  and  pour  out  the  mucus, 

*  Dr.  John  Davy,  Phil.  Trans.  1834. 

t  On  this  subject,  Dr.  Davy  remarks — *'  It  is  an 
interesting  fact  that  the  nerves  of  the  stomach  are 
derived  from  those  supplying  the  electrical  organs. 
Perhaps  superfluous  electricity,  when  not  required 
for  the  defence  of  the  animal,  may  be  directed  to 
this  organ  to  promote  digestion.  In  the  instance  of 
a  fish  which  I  had  in  my  possession  alive  many  days, 
and  which  was  frequently  excited  to  give  shocks,  di- 
gestion appeared  to  have  been  completely  arrested; 
when  it  died,  a  small  fish  was  found  in  its  stomach, 
much  in  the  same  state  as  when  it  was  swallowed — 
no  portion  of  it  had  been  dissolved." 


ANIMAL  ELECTRICITY. 


91 


Fig.  48. 


The  right  electrical  organ  divided  horizontally  at  the  place  where  the  nerves  enter,  the  upper  half 

being  turned  outwards. 

A  A,  The  first  or  anterior  electrical  nerve. 

B  B,  The  second  or  middle  nerve  arising  behind  the  gill. 

C  C,  The  anterior  branch  of  the  third  nerve  arising  behind  the  second  gill. 

D  D,  The  posterior  branch  of  the  third  nerve  arising  behind  the  third  gill. 


which,  probably,  serves  as  a  medium  of  com- 
munication between  the  electrical  organs  ;  being, 
apparently,  a  better  conductor  of  electricity 
than  either  the  naked  skin  or  salt  water* 

With  regard  to  the  development  of  the  elec- 
trical organs,  it  appears  that,  in  the  earliest 
stages  of  foetal  growth,  they  cannot  be  seen.  In 
a  foetus  of  about  seven-tenths  of  an  inch  in 
length,  Dr.  Davy  found  neither  electrical  organs 
nor  fins.  In  another,  more  than  one  inch  long, 
the  organs  were  beginning  to  appear,  and  the 
roots  of  the  electrical  nerves  were  visible, 
although  the  brain  could  not  be  seen.  In  this 
stage,  the  external  branchial  filaments  •  were 
about  six-tenths  of  an  inch  in  length,  and  pre- 

*  Davy,  Phil.  Trans.  1832.  Also  Annates  du 
Mus.  no.  v.,  in  which  E.  Geoffroy  endeavoured  to 
show  that  the  common  mucous  system  of  rays  is 
absent  in  the  torpedo,  and  that  its  place  is  supplied 
by  the  columns  of  the  electrical  organs,  which  he 
believed  to  be  analogous  to  the  mucous  ducts. 


sented  a  very  remarkable  appearance.  In  a 
foetus  of  two  inches  and  a  half  long,  the  electrical 
organs  were  distinctly  formed,  and  the  branchial 
filaments  still  long.  These  filaments  Dr.  Davy 
supposes  to  be  destined  to  absorb  matter  for  the 
formation  of  the  electrical  organs,  and,  perhaps, 
the  gills  and  adjoining  mucous  glands.  They 
are  most  numerous  and  of  greatest  length  while 
the  electrical  organs  are  forming,  appearing  just 
before  these  organs  begin  to  be  developed,  and 
being  removed  when  they  are  tolerably  com- 
plete.— In  no  other  allied  fishes  is  there  the 
same  "  elaborate  apparatus  of  filaments ;" 
where  they  do  exist,  they  are  less  numerous  and 
very  much  shorter. 

2.  The  electrical  organs  in  the  Gymnotus. — 
This  fish  has  a  general  resemblance  in  form  to 
the  common  eel.  Its  electrical  organs  occupy 
nearly  one-third  of  its  whole  bulk.  They  are 
formed  by  two  series  of  tendinous  membranes  ; 
one  of  which  consists  of  horizontal  plates,  run- 


92 


ANIMAL  ELECTRICITY. 


ning  from  the  abdominal  cavity  towards  the  tail, 
placed  one  above  another  with  short  distances 
between  them  ;  the  other  of  perpendicular  plates, 
forming,  along  with  the  other  series,  small  quad- 
rangular cells,  which  are  filled  with  a  semi-gela- 
tinous transparent  substance.  This  structure  is 
divided  longitudinally  into  two  pairs  of  distinct 
organs,  one  considerably  larger  than  the  other. 
The  greater  pair  (k  k,  fig.  49)  lies  above  the 
other,  and  immediately  beneath  the  long  mus- 
cles of  the  tail.    They  are  separated  from  one 


another  by  part  of  these  muscles,  by  the  air- 
bladder,  and  by  a  central  membranous  partition. 
They  occupy  a  large  portion  of  the  lower  and 
lateral  parts  of  the  body,  and  are  covered  exter- 
nally only  by  the  common  integuments.  The 
smaller  pair  are  covered  also  by  the  muscles  of 
the  caudal  fin.  Both  pairs  of  organs  are  some- 
what angular  in  their  transverse  section,  trun- 
cated anteriorly,  tapering  towards  the  tail.  In 
theGymnotus  dissected  by  John  Hunter,*  which 
was  about  two  feet  four  inches  long,  the  large 


Fig.  49. 


The  surface  of  the  electrical  organs  of  the  Gymnotus,  on  the  right  side,  after  removal  of  the  integuments. 

a,  the  lower  jaw.  b,  the  abdomen,  c,  anus,  d,  pectoral  fin.  e,  dorsal  surface  of  fish.  //,  anal 
fin.  gg,  skin  turned  back,  h  h,  lateral  muscles  of  the  anal  fin  turned  back  with  the  skin,  to  expose 
the  small  electrical  organ,  i,  part  of  this  muscle  left  in  its  place,  k  k,  the  large  electrical  organ.  /  I, 
the  small  electrical  oiyan.  m  m,  the  substance  which  divides  the  large  organ  from  the  small,  n,  a 
space  from  which  the  partition  is  removed. 

organ  of  one  side  was  about  one  inch 
and  one  quarter  in  breadth  at  its 
thickest  part,  and  in  this  space  there 
were  thirty-four  longitudinal  septa. 
(In  a  specimen  examined  by  Dr. 
Knox,  there  were  thirty-one  of  these 
septa.f)  The  smaller  organ  in  the 
same  fish  was  about  half  an  inch  in 
breadth,  and  contained  fourteen  septa, 
which  were  slightly  waved.  The  per- 
pendicular or  transverse  membranes 
are  placed  much  more  closely  toge- 
ther than  those  of  the  other  series. 
John  Hunter  and  Dr.  Knox  counted 
two  hundred  and  forty  of  them  in 
an  inch.  They  are  of  a  softer  texture 
than  the  longitudinal  plates.  It  ap- 
pears probable  (as  Hunter  suggested) 
that  these  septa,  longitudinal  and 
transverse,  answer  the  same  purpose 
as  the  columns  in  the  torpedo.  La- 
cepede  calculated  that  the  discharg- 
ing surface  of  these  organs  in  a  fish 
four  feet  in  length  is,  at  least,  one 
hundred  and  twenty-three  square  feet 
in  extent;  while  in  a  torpedo  of  ordi- 
nary size,  the  discharging  surface  is 
only  about  fifty-eight  feet  square. 

The  nerves  of  the  electrical  organs 
of  the  Gymnotus  are  derived  from  the 
spinal  marrow  alone.  They  are  very 
large  and  numerous,  and  are  divided 
into  very  fine  twigs  on  the  cells  of  the 
organs.  Dr.  Knox  counted  fifteen 
nervous  branches  distributed  to  each 
inch  of  the  organ.  He  describes 
them  as  being  flattened  like  the  ci- 
liary nerves  of  Mammalia.  Each 

*  Phil.  Trans.  Ixv.  1775. 
t  Edin.  Journ.  of  Science,  i.  96.  1824. 


A  transverse  section  of  the  Gymnotus. 

a,  the  surface  of  the  side  of  the  fish,  b,  the  anal  fin.  c  c, 
cut  ends  of  the  dorsal  muscles,  d,  cavity  of  the  air-bladder. 
e,  body  of  the  spine.  /,  spinal  marrow,  g,  aorta  and  vena 
cava,  h  h,  cut  ends  of  the  two  large  electrical  organs,  i  i, 
cut  ends  of  the  two  small  organs,  k,  partition  between  the 
two  organs. 


ANIMAL  ELECTRICITY. 


93 


nerve  is,  for  the  most  part,  divided  into  five 
distinct  branches  before  entering  the  electrical 
organs ;  and  these  are  again  subdivided  into, 
at  least,  as  many  branches  as  there  are  longi- 
tudinal septa.  Rudolphi  describes  a  nerve 
formed  from  branches  of  the  fifth  pair  and 
sympathetic,  which  runs  beneath  the  lateral 
line,  over  the  surface  of  the  electrical  organs, 
but  does  not  enter  them.  This  has,  by  some, 
been  supposed  to  be  an  electrical  nerve,  but 
without  sufficient  reason.* 

3.  The  electrical  organs  in  the  Silurus. — 
The  only  organ  that  can  be  regarded  as  con- 
nected with  the  electrical  function  in  this  fish 
is  a  thick  layer  of  dense  cellular  tissue,  which 
completely  surrounds  the  body  immediately 
beneath  the  integuments.  So  compact  is  it 
that,  at  first  sight,  it  might  be  mistaken  for  a 
deposit  of  fatty  matter.  But,  under  the  mi- 
croscope, it  appears  to  be  composed  of  ten- 
dinous fibres,  closely  interwoven,  the  meshes 
of  which  are  filled  with  a  gelatinous  substance. 
This  organ  is  divided  by  a  strong  aponeurotic 
membrane  into  two  circular  layers,  one  outer, 
lying  immediately  beneath  the  corion,  the  other 
interna],  placed  above  the  muscles.  Both  or- 
gans are  isolated  from  the  surrounding  paits 
by  a  dense  fascia,  excepting  where  the  nerves 
and  bloodvessels  enter.  The  cells  or  meshes 
in  the  outer  organ,  formed  by  its  reticulated 
fibres,  are  rhombic  in  shape,  and  very  minute, 
so  as  to  require  a  lens  to  see  them  well.  The 
component  tissue  of  the  inner  organ  is  some- 
what flaky,  and  also  cellular. 

The  nerves  of  the  outer  organ  are  branches 
of  the  fifth  pair,  which  runs  beneath  the  lateral 
line  and  above  the  aponeurotic  covering  of  the 
organ.  This  aponeurosis  is  pierced  by  many 
holes  for  the  transmission  of  the  nerves,  which 
are  lost  within  the  cellular  tissue  of  the  organ. 
The  intercostals  supply  the  inner  organ  :  their 
electrical  branches  are  numerous  and  remarka- 
bly fine.f 

The  organs  of  the  other  known  electrical 
fishes  have  not  yet  come  under  the  notice  of 
any  anatomist. 

In  taking  a  general  view  of  these  interesting 
organs,  we  are  struck  with  the  existence  of  a 
certain  degree  of  analogy  amongst  them,  and 
yet  we  fail  to  discover  such  resemblances  as 
might  be  expected,  and  such  as  exist  between 
the  structures  of  other  organs  performing  the 
same  functions  in  different  animals.  Here  we 
have  tendinous  membranes  variously  arranged, 
yet  all  so  as  to  form  a  series  of  separate  cells 
filled  with  a  gelatinous  matter.  But  how  great 
is  the  difference  between  the  large  columnar 
cell  in  the  torpedo  full  of  delicate  partitions, 
and  the  minute  rhombic  cells  of  the  Silurus  ! 
All,  however,  are  equally  supplied  with  nerves 
of  very  great  size,  larger  than  any  others  in  the 
same  animals;  and,  indeed,  we  may  venture 
to  say,  larger  than  any  nerve  in  any  other  ani- 
mal of  like  bulk. 

"  Abhandl.  der  Acad.  v.  Berlin,  1820-21.  229, 
and  Blainville,  Princ.  d'Anat.  Comp.  i.  232. 

t  Rudolphi,  (Abhandl.  der  Acad.  v.  Berlin. 
1824.)  140. 


The  organs  vary  in  different  fishes  ;  first,  in 
situation  relatively  to  other  organs.  They 
bound  the  sides  of  the  head  in  the  torpedo ; 
run  along  the  tail  of  the  Gymnotus,  and  sur- 
round the  body  of  the  Silurus  ;  secondly,  in 
having  different  sources  of  nervous  energy  ; 
and,  thirdly,  in  the  form  of  the  cells.  No 
other  fishes  have  aponeuroses  so  extensive,  or 
such  an  accumulation  of  gelatine  and  albumen 
in  any  cellular  organ.  Broussonet  remarked 
that  "  all  the  electrical  fishes  at  present  known 
to  us,  although  all  belonging  to  different  classes, 
have  yet  certain  characters  in  common.  All, 
for  instance,  have  the  skin  smooth,  without 
scales,  thick,  and  pierced  with  small  holes, 
most  numerous  about  the  head,  and  which 
pour  out  a  peculiar  fluid.  Their  fins  are 
formed  of  soft  and  flexible  rays,  united  by 
means  of  dense  membranes.  Neither  the 
Gymnotus  nor  torpedo  has  any  dorsal  fin ; 
the  Silurus  has  only  a  small  one,  without  rays, 
situated  near  the  tail.    All  have  small  eyes."* 

X.  Analogies  of  animal  electricity . — Setting 
aside  the  vague  hypotheses  of  the  older  philo- 
sophers, (some  of  whom  attributed  the  phe- 
nomena produced  by  the  peculiar  power  of 
electrical  fishes  entirely  to  the  mechanical  effect 
of  certain  rapid  motions  of  their  surface,  and 
others  to  the  influence  of  currents  of  minute 
corpuscules  flowing  from  the  body  of  the  fish 
in  the  act  of  discharging,)  we  can  have  no  dif- 
ficulty in  referring  this  very  remarkable  series 
of  phenomena  to  the  agency  of  some  power 
very  analogous  to  common  or  voltaic  elec- 
tricity, which  seems  to  stand  in  the  same  rela- 
tion to  these  as  they  do  to  electricity  derived 
from  other  sources.-f- 

It  was  by  Muschenbroek  that  the  effects 
of  the  torpedo's  discharge  were  first  referred 
to  electricity.  He  was  led  to  imagine  that 
the  agent  producing  the  shock  was  truly 
electrical  from  the  similarity  of  its  effects 
to  those  of  the  discharge  of  the  Leydenjar. 
Succeeding  observations,  however,  as  we 
have  seen,  have  shewn  that  certain  differences 
exist  between  the  phenomena  produced  by 
Animal  Electricity  and  those  observed  in  con- 
nexion with  the  discharge  of  the  Leyden  jar  : 
the  chief  of  these  are — its  passage  through  air 
only  to  a  very  small  distance;  its  producing 
only  very  slight  igniting  effects  even  when  con- 
siderably accumulated ;  and  its  manifesting 
but  feebly  the  phenomena  of  attraction  and 
repulsion.  Further,  it  affects  the  multiplier 
more  strongly  than  common  electricity  does 
under  ordinary  circumstances,  and  its  chemical 
effects  are  more  distinct.  From  voltaic  elec- 
tricity it  is  distinguished  by  the  comparative 
feebleness  of  its  power  of  decomposing  water; 
by  the  greater  sharpness  of  the  shock  caused 
by  the  discharge,  and  by  the  weakness  of  its 
magnetizing  power. 

Only  four  of  the  eight  experimental  effects 
enumerated  by  Dr.  Faradayf  as  characteristic 

*  Mem.  de  l'Acad.  de  Paris,  1782.  693. 
t  It  is  interesting  to  know  that  the  Arabic  name 
of  the  torpedo  (Rausch)  means  also  lightning. 
X  Philos.  Trans.  1833. 


94 


ANIMAL  ELECTRICITY. 


of  common  and  voltaic  electricity  are  pro- 
duced by  animal  electricity;  which  appears 
to  be  sufficient  to  prove  that  the  latter  is  as 
much  a  peculiar  power  distinct  from  these  as 
are  the  agents  called  magneto-electricity  and 
thermo-electricity.  Perhaps,  however,  what 
we  at  present  regard  as  so  many  powers  dif- 
fering from  one  another  in  their  natures,  may 
be  merely  modifications  of  the  same  power, 
varied  in  its  sensible  properties  by  changes  in 
the  circumstances  under  which  they  are  mani- 
fested. This  latter  view  is  that  taken  by  D.r. 
Wilson  Philip,  who  holds  that  Animal  Elec- 
tricity is  just  common  electricity  modified  in 
its  properties  by  those  of  life,  under  the  in- 
fluence of  which  it  operates  in  the  living 
animal. 

Sir  Humphry  Davy  thought  he  saw  a 
stronger  analogy  between  common  and  animal 
electricity,  than  between  voltaic  and  animal 
electricity,  but  concluded  that  the  latter  would 
be  found  by  more  extended  researches  than 
he  was  able  to  make  to  be  "  of  a  distinctive 
and  peculiar  kind."*  Cavendish,  on  the  other 
hand,  believed  that  there  is  a  complete  identity 
between  common  electricity  and  that  of  fishes. 
And  this  lie  laboured  to  prove  by  imitating 
several  of  the  peculiarities  of  the  discharge  of 
the  torpedo  by  a  particular  arrangement  of 
small  Leyden  jars,  forming  a  battery,  from 
which  the  electricity  was  discharged  in  large 
quantity  but  of  low  intensity.f  Others,  again, 
have  attempted  to  trace  a  certain  resemblance 
between  the  structure  of  the  electrical  organs 
of  the  torpedo  and  the  formation  of  the  voltaic 
pile,  "  inasmuch  as  they  are  formed  of  alter- 
nate layers  of  moistened  conductors  of  dif- 
ferent natures,  to  wit,  of  membranous  parti- 
tions, and  of  gelatinous  and  albuminous  fluid." 
(Tiedemann.)  They  suppose  that  the  nerves, 
being  spread  over  one  side  of  the  transverse 
partitions  of  the  cells,  produce  opposite  states 
of  electrical  tension  on  the  two  sides  of  the 
partition.  In  the  present  imperfect  state  of 
electrical  science,  all  such  hypotheses  are  un- 
satisfactory. 

The  only  conclusions  which,  in  our  opinion, 
can  be  legitimately  drawn  from  the  accumu- 
lated facts  on  the  subject  are — that  the  shock 
given  by  electrical  fishes  is  caused  by  an  agent 
closely  allied  in  its  nature  to  common  elec- 
tricity and  other  like  powers  ;}  and  that  the 
developement  and  discharge  of  this  agent  are 
strictly  dependent  on  the  integrity  of  the  ner- 
vous communication  between  certain  peculiar 
organs  and  the  great  nervous  centres. 

It  is  evident  that  the  nervous  system  plays 
a  very  important  part  in  the  electrical  function. 
But  whether  its  influence  merely  stimulates 
the  electrical  organs  to  do  what  their  organic 

*  Philos.  Trans.  1829.  16. 
t  Philos.  Trans.  1776.  196. 

%  The  latest  experiments  on  the  subject,  with 
which  we  are  acquainted,  are  those  of  Messrs. 
Becquerel  and  Breschet,  reported  to  the  Academy 
of  Sciences  in  October,  1835,  (Ann.  des  Sciences 
Nat.  n.  s.  iv.  253,)  which  seem  to  have  been  per- 
formed with  great  care.  The  experimenters  com- 
pletely satisfied  themselves  that  the  shock  of  the 
torpedo  is  the  result  of  an  electrical  discharge .  ■ 


structure  renders  them  capable  of  doing,  or 
really  supplies  them  with  a  stream  of  the  im-, 
ponderable  agent  which  they  accumulate,  and 
then,  under  voluntary  impulses,  discharge,,  is 
still  a  point  for  further  investigation.    In  the 
structure  of  the  electrical  organs,  we  do  not 
see  any  arrangement  such  as  researches  in  elec- 
tricity artificially  developed  lead  us  to  believe 
fitted  either  to  produce  or  to  accumulate  elec- 
tricity.   But  this  is  in  itself  no  reason  why 
we  should  conclude  that  the  organs  have  not 
such  powers.    It  seems  more  in  accordance 
with  what  we  know  of  the  actions  of  other 
parts  of  the  animal  frame,  to  believe  that  they 
do  possess  such  powers.  But — if  the  elec- 
trical organs,   by  their  organic  structure,  be 
fitted  to  develope  and  to  discharge  electricity 
under  the  nervous  influence,  just  as  a  gland 
secretes  its  peculiar  fluid  and  its  ducts  eject  it, 
why  (it  may  be  asked)  are  the  nerves  going  to 
these  organs  of  so  very  great  a  size  compared 
with  the  same  parts  in  other  organs  of  similar 
bulk  and  very  energetic  action  ?    Is  their  sub- 
jection to  the  will  of  the  animal  sufficient  to 
account  for  the  difference  ?  or  does  it  indicate, 
as  some  physiologists  maintain,  that  the  ner- 
vous influence  does  more  in  this  case  than 
merely  supply  the  vital  stimulus  such  as  is 
received  by  all  other  organs  in  common  ?  In 
other  words — is  the  agent  discharged  by  the 
fish  as  electricity  first  developed  in  the  ner- 
vous centres,  and  only  accumulated  in  the 
electrical  organs ;  and  is  this  agent  identical 
with  common  nervism  ?    To  these  questions 
we  cannot  yet  give  a  satisfactory  reply.  They 
point  the  way  to  some  very  interesting  and  im- 
portant fields  of  investigation,  and  cheer  us 
with  the  hope  of  considerably  extending  our 
acquaintance  with  the  physiology  of  the  nerves, 
on  the  supposition  that  the  phenomena  of  ani- 
mal electricity  shall  one  day  be  proved  to  be 
owing  to  an  accumulation  and  discharge  of  the 
very  same  agent  that  causes  contraction  of 
muscles,  &c.    Such  a  view  appears  to  have 
been  taken  of  this  subject  by  Sir  II.  Davy 
when  he  remarked,*  "  there  seems  a  gleam  of 
light  worth  pursuing  in  the  peculiarities  of 
animal  electricity, — its  connexion  with  so  large 
a  nervous  system, — its  dependence  on  the  will 
of  the  animal, — and  the  instantaneous  nature 
of  its  transfer,  which  may  lead,  when  pursued  by 
adequate  inquirers,  to  results  very  important  for 
physiology."  Treviranus,  in  1818,  suggested  the 
likelihood  of  the  power  concerned  m  the  ma- 
nifestation of  electrical  phenomena  by  animals, 
being  one  of  those  on  which  continuance  of 
life  in  general  depends.    "  Perhaps,"  said  he,f 
"  it  is  the  same  power  which  enables  the  tor- 
pedo to  give  electric  shocks  that  is  the  imme- 
diate cause  of  the  contraction  of  muscular 
fibres."     The  same  hypothesis  is  thus  ex- 
pressed by  Carus4    "  Numerous  nerves  are 
distributed  upon  the  cells  of  the  electrical 
organs,  and  as  it  is  through  the  agency  of 

*  Philos.  Trans.  1828. 
t  Biologie.  v.  141. 

\  Traite  element,  d'anat.  comp.  2d  edit.  i.  392. 
(French  translation  by  Jourdan. ) 


ANIMAL  ELECTRICITY. 


95 


these  nerves  that  the  organs  act,  it  is  not  im- 
possible that  the  nervous  influence  itself  is 
accumulated  in  these  cells  as  in  condensers, 
and  that  it  is  discharged  at  will,  just  as  this 
influence  is  accumulated  in  the  muscular  tissue 
to  produce  contraction  of  its  fibres."  It  was 
reflection  on  the  phenomena  of  animal  elec- 
tricity that  led  Dr.  Wollaston  to  form  the  hy- 
pothesis, which  he  supported  with  so  much 
ability,  of  secretion  in  general  being  depen- 
dant on  electricity,  conveyed  by  the  nerves, 
and  acting  on  the  secerning  organs.*  Dr. 
Wilson  Philip,  also,  thinks  that  the  circum- 
stances under  which  electrical  action  is  mani- 
fested by  fishes  go  to  the  support  of  his  theory 
of  the  nervous  influence  being  identical  with 
common  and  voltaic  electricity.  Dr.  Faraday 
says  that,  from  the  time  that  it  was  shewn  that 
electricity  could  perform  the  functions  of  the 
nervous  influence,  he  has  had  no  doubt  of  their 
very  close  relation,  and  probably  as  effects  of 
one  common  cause.  To  the  numerous  list  of 
learned  observers  who  have  speculated  on  this 
interesting  subject,  we  have  to  add  the  re- 
spected name  of  Sir  John  Herschel,  who 
imagines  that  the  present  state  of  electrical 
science  warrants  the  conjecture,  that  the  brain 
and  spinal  marrow  form  an  electric  organ, 
which  is  spontaneously  discharged  along  the 
nerves,  at  brief  intervals,  "  when  the  tension 
of  the  electricity  reaches  a  certain  point. "f 
Meissner,  again,  supposes  that  the  blood  be- 
comes charged  with  electricity  in  the  lungs, 
during  the  chemical  process  of  respiration ; 
that  the  electricity  immediately  traverses  the 
nerves  of  the  lungs,  and  then  the  other  parts 
of  the  ganglionic  system  ;  that  hence  the  cen- 
tral organs  of  the  nervous  system  become 
charged  ;  and  that  the  brain,  on  and  through 
which  the  will  acts,  being  charged,  excites  the 
several  organs  to  activity  through  the  medium 
of  their  respective  nerves,  along  which  electric 
currents  are  passed.}  The  facts,  (in  addition 
to  those  which  have  chiefly  engaged  our  atten- 
tion in  this  article,)  upon  which  such  theories 
are  built  are, —  (1)  that  the  muscles  of  an 
animal  recently  dead  contract  when  common 
electricity  passes  through  them,  just  as  they  do 
when  they  are  subject  to  the  animal's  will ; 
(2)  that  voltaic  electricity  acts  upon  secreting 
organs,  so  as  to  enable  them  in  some  degree  to 
carry  on  their  functions  after  their  proper  nerves 
have  been  cut;  and  (3)  that  the  same  agent 
appears  to  influence  powerfully  the  capillary 
circulation.  But,  although  these  facts,  taken 
along  with  what  we  know  of  the  phenomena 
of  the  electricity  of  fishes,  certainly  do  appear 
to  favour  the  views  to  which  we  have  just 

■*  Phil.  Mag.  xxxiii.  488. 

f  Discourse  on  the  Study  of  Nat.  Phil.  343. 
t  Syst.  der  Heilkunde.  Wien.  1832.  If  hypo- 
theses such  as  these  should  hereafter  be  proved  to 
express  the  true  state  of  the  case,  the  electrical 
fishes  will  become  objects  of  great  interest  to  the 
physiologist,  as  presenting  him  with  opportunities, 
such  as  no  other  animals  afford,  of  studying  in 
accumulation  the  properties  of  that  wonderful  agent, 
which  is  the  moving  power  of  the  animal  organiza- 
tion, and  a  very  important  link  in  the  chain  of 
causes  and  effects  bj<  which  life  is  manifested. 


alluded,  there  are  yet  other  facts  which  are  so' 
hostile  to  them  as  to  make  it  probable  that 
they  do  not  express  the  truth.  For  instance, 
the  most  carefully  conducted  experiments  have 
failed  to  demonstrate  the  existence  of  electric 
currents  through  muscles  during  their  contrac- 
tion; which,  from  all  that  is  known  of  the 
phenomena  exhibited  by  electricity  in  other 
circumstances,  it  may  be  presumed  would  not 
have  been  the  case  had  it  been  the  immediate 
stimulant  of  muscular  contraction.  M.  Per- 
son has  applied  the  poles  of  a  galvanometer  to 
the  spinal  marrow  without  obtaining  any  indi- 
cations of  the  existence  of  electrical  currents 
through  its  substance.  The  subjects  of  Per- 
son's experiments  were  cats,  dogs,  rabbits, 
eels,  and  frogs.  The  spinal  canal  having  been 
opened,  the  piles  of  the  galvanometer  were 
placed  in  communication  with  the  anterior  and 
posterior  columns  of  the  cord.  This  was  clone 
at  different  parts,  after  the  roots  of  the  nerves 
had  been  cut.  Small  plates  of  platina,  with 
which  the  wires  of  the  instrument  were  armed, 
were  thrust  into  the  cerebellum  and  into  several 
of  the  largest  nerves.  These  experiments  were 
repeated  after  the  animals  had  been  placed 
under  the  influence  of  strychnia.  But  there 
was  no  certain  indication  of  electricity  ob- 
tained, although  the  most  delicate  instruments 
were  used.*  Person's  experiments  have  been 
repeated  by  Muller  with  the  same  results. 
Messrs.  Prevost  and  Dumas,  however,  state 
that,  having  armed  the  branches  of  their  gal- 
vanometer with  two  wires  of  platina,  exactly 
alike,  and  having  plunged  one  of  them  into 
the  muscles  of  a  frog's  leg,  while,  with  the 
other,  heated  to  redness,  they  touched  its 
nerves,  they  saw  considerable  deviations  of  the 
needle  of  the  instrument  follow  the  contrac- 
tions of  the  muscles.f  But  seeing  that  the 
electricity  made  manifest  in  this  experiment 
may  have  been  developed  rather  by  the  con- 
tact of  the  hot  wire  and  the  nerves  than  by  the 
nervous  actions,  we  cannot  admit  that  it  is 
sufficient  to  prove  the  existence  of  electrical 
currents  in  muscles  during  their  contraction. 
Dr.  Faraday,  also,  has  lately  experimented  on 
living  muscles  with  the  very  delicate  galvano- 
meter invented  by  himself,  but  has  entirely 
failed  to  obtain  indications  of  moving  electri- 
city. Negative  results  such  as  these,  obtained 
by  so  many  practised  observers,  are  sufficient 
to  induce  us  to  withhold  our  assent  from  those 
theories  which  make  nervism  identical  with 
electricity,  until  the  whole  subject  shall  have 
been  more  fully  investigated. 

As  in  some  degree  illustrative  of  the  pheno- 
mena of  animal  electricity,  properly  so  called, 
we  must  here  take  notice  of  the  manifestation 
of  common  electricity  in  animal  substances  and 
in  living  animals. 

The  mere  contact  of  heterogeneous  bodies  is 

*  Journal  de  Physiol,  x,  217.  Some  years  ago 
M.  Pouillet  announced  that  he  had  witnessed 
electrical  phenomena  during  the  operation  of  the 
acupuncture  of  muscles  ;  but  he  has  since  con- 
fessed that  he  was  deceived. 

f  Edwards,  De  l'iiifiuencc  ties  agens  physiques 
sur  la  Vie,  in  Appendix. 


96 


ANIMAL  ELECTRICITY. 


sufficient  for  the  development  of  electricity;  and 
animal  tissues  of  dissimilar  natures,  both  living 
and  dead,  obey  the  same  law  as  other  sub- 
stances in  this  respect.  For  instance,  a  kind  of 
voltaic  pile  has  been  formed  by  building  up  layers 
of  muscle  and  nerve  placed  one  above  the  other 
alternately;  (Buntzen :)  also  by  placing  one  upon 
another  alternate  layers  of  muscular  fibre  and 
brain,  separated  by  a  porous  substance,  soaked 
in  salt-water.  (Lagrave.)  Another  such  has 
been  made  with  plates  of  one  kind  of  metal, 
fresh  muscle,  and  salt-water,  or  blood,  which 
acted  on  the  galvanometer.  When  the  con- 
ductors of  a  galvanometer  (Schweigger's)  are 
armed  with  plates  of  platina,  on  one  of 
which  a  piece  of  muscle  of  a  few  ounces  in 
weight  is  placed,  and  the  conductors  are  then 
plunged  in  blood  or  in  a  weak  solution  of  salt, 
a  deviation  of  the  magnetic  needle  of  the  in- 
strument is  perceptible.  (Prevost  and  Dumas.) 
The  same  happens  when  to  one  conductor  is 
applied  a  plate  of  platina  moistened  with  mu- 
riate of  antimony  or  nitric  acid,  to  the  other  a 
piece  of  nerve,  muscle,  or  brain,  and  both  are 
brought  into  contact.  (Majendie.)  Dry  piles 
of  considerable  electrical  power  may  be  formed 
of  organic  materials  alone,  without  the  interven- 
tion of  metals.  If  concentrated  extracts  of 
organic  bodies  (animal  or  vegetable)  be  spread 
upon  thin  paper,  and  piles  be  built  up  of  discs 
cut  from  this  paper,  so  that  two  dissimilar  layers 
be  separated  by  two  thicknesses  of  the  paper, 
so  much  electricity  is  developed  that  the  elec- 
trometer is  affected.  (Kcemtz.)  When  two 
persons,  both  insulated,  join  hands,  electricity 
is  developed  sufficiently  to  affect  Coulomb's 
electroscope.  And,  if  the  contraction  of  mus- 
cles, the  nervous  connexion  of  which  with  the 
living  body  has  been  destroyed,  be  considered 
as  a  proof  that  thpy  are  subject  to  the  influence 
of  electricity,  there  are  numerous  experiments 
on  record  tending  to  prove  that  electricity  is 
evolved  by  the  mere  contact  of  two  dissimilar 
animal  substances.  Galvani,  Volta,  Humboldt, 
Aldini,  Kellie,  and  Miiller,  have  all  found  that 
when  the  muscles  and  the  great  nerves  of  a 
frog's  limb  are  touched  synchronously  with  a 
piece  of  the  muscle  of  a  warm-blooded  animal, 
weak  contractions  of  the  frog's  muscles  ensue ; 
and  that,  when  the  crural  muscles  are  cut  and 
folded  back  so  as  to  touch  the  lumbar  nerves, 
muscular  contractions  are  perceived  in  the  lower 
part  of  the  limb.  Aldini  excited  most  powerful 
contractions  by  bringing  the  nerves  of  a  warm- 
blooded animal  into  contact  with  the  muscles 
of  a  cold-blooded  animal,  and  vice  versa.  And 
Miiller  has  further  found  that  contractions  are 
excited  by  touching  the  moistened  skin  of  the 
leg  with  the  nerves  of  the  thigh  dissected  out 
and  turned  down  upon  them  ;  the  nerves  being- 
held  by  means  of  an  insulating  rod.* 

Tiedemann  thus  states  the  general  results  of 
experiments  such  as  these.  "1.  The  nerves 
of  the  muscles  in  which  it  is  proposed  to  excite 
convulsions  must  make  part  of  the  chain. 
2.  The  nerve  or  portion  of  nerve  which  is  to 

*  Handbuch  der  Physiol,  des  Mensclicn.  Berlin, 
1833. 


make  part  of  the  chain  must  be  isolated  as 
completely  as  may  be,  and  no  other  conductor 
must  produce  derivation  in  this  portion  of  the 
chain,  so  as  to  oblige  the  electric  current,  when 
developed  in  the  chain,  to  take  a  course  through 
the  nerves.  3.  Cceteris  paribus,  the  convulsions 
are  so  much  stronger,  and  are  manifested  over  a 
greater  extent,  as  the  nervous  portion,  acting  as 
a  conductor,  enters  into  the  chain.  4-  The 
convulsions  are  so  much  more  powerful,  and 
last  the  longer,  as  the  chain  is  quickly  formed, 
and  the  surface  with  which  the  parts  consti- 
tuting it  are  in  contact  is  extensive."*  And 
lastly,  we  now  know  that  even  the  evaporation 
of  fluids,  and  changes  in  the  molecular  consti- 
tution of  both  solids  and  fluids  are  always 
accompanied  by  electrical  excitation.  . 

Applying  these  facts  to  our  knowledge  of 
the  various  processes  of  the  animal  ceconomy, 
we  cannot  but  conclude  that,  in  the  course  of 
the  many  interchanges  that  are  constantly  taking 
place  amongst  the  component  particles  of  all 
living  organs,  electricity  (perhaps  modified  by 
the  organic  forces)  must  be  developed  alto- 
gether independently  of  nervous  influence.  It 
is  certain,  however,  that  electricity  flowing  from 
this  source  is  very  feebly  manifested ;  at  least  it 
affects  our  best  electrometers  in  a  very  incon- 
siderable degree.  Saussure  frequently  ex- 
amined the  electricity  of  his  own  body  by 
means  of  Volta's  electrometer,  used  along  with 
a  condenser,  but  always  failed  to  perceive  any 
indications  of  free  electricity  while  he  was 
entirely  naked.  It  was  also  imperceptible 
while  lie  perspired  freely,  and  when  his  clothing 
was  cold.  Under  other  circumstances,  he  found 
the  electricity  of  his  body  sometimes  positive, 
and  at  other  times  negative ;  but  he  could  not 
determine  the  causes  of  these  variations.  Simi- 
lar observations  were  made  by  Hemmer  of 
Mannheim  in  1786,  both  on  the  electricity  of 
his  own  body,  and  on  that  of  many  other  indi- 
viduals placed  in  various  circumstances.  He 
obtained  the  following  results.  1.  Electricity 
is  developed  in  all  men,  but  varies  in  intensity 
and  in  nature  in  different  individuals.  2.  The 
character  and  intensity  of  the  electricity  fre- 
quently varies  in  the  same  person.  In  2422 
experiments,  it  was  1252  times  positive,  771 
negative,  and  399  times  imperceptible.  3.  When 
the  body  is  at  rest  and  warm,  its  electricity  is 
always  positive.  4.  When  the  surface  is  much 
cooled,  the  electricity  becomes  negative.  5.  It 
is  also  negative  when  the  muscular  vigour  is 
diminished.  More  recently  this  subject  has 
been  investigated  by  Messrs.  Pfaff  and  Ahrens.f 
They  used  a  gold-leaf  electrometer;  and  the 
subjects  of  their  observations  were  insulated. 
The  collecting  plate  screwed  on  the  electrometer 
was  touched  by  the  person  experimented  upon. 
The  upper  plate  of  the  same  was  placed  in 
communication  with  the  ground  by  means  of 
conductors.  The  results  which  they  thus  pro- 
cured were  as  follows: — 1.  The  electricity  of 
healthy  men  is  generally  positive.  2.  Irritable 
men  of  sanguine  temperament  have  more  free 

*  Pliysiol.  trans!,  by  Drs.  Gully  and  Lane,  276". 
t  Meckel's  Arehiv.  iii.  161. 


ANIMAL  ELECTRICITY. 


97 


electricity  than  those  of  a  phlegmatic  tempera- 
ment. 3.  An  increased  accumulation  of  elec- 
tricity takes  place  in  the  evening.  4.  Spirituous 
drinks  augment  its  intensity.  5.  The  elec- 
tricity of  Women  is  more  frequently  negative 
than  that  of  men.  6.  In  winter,  while  the  body 
is  very  cold,  no  electricity  is  manifested,  but  it 
gradually  reappears  as  the  body  is  warmed. 
7.  The  whole  body  naked,  as  well  as  every  part 
of  .it,  shews  the  same  phenomena.  8.  During 
the  existence  of  rheumatism,  the  electricity  is 
greatly  diminished  in  intensity,  but  as  the  dis- 
ease declines  it  again  increases.  Gardini  found 
that  the  electricity  of  women  during  menstrua- 
tion and  pregnancy  is  negative. 

Some  individuals  exhibit  electrical  pheno- 
mena much  more  readily  than  others.  Some 
persons,  for  instance,  hardly  ever  pull  off  articles 
of  dress  worn  next  the  skin  without  sparks  and 
a  crackling  noise  being  produced.  It  is  related 
of  a  certain  monk  that  sparks  were  always 
emitted  from  his  hair  when  it  was  stroked  back- 
wards ;  and  of  an  Italian  lady  that  her  skin, 
when  rubbed  with  a  linen  cloth,  gave  out  sparks, 
attended  with  a  crackling  noise.  The  same 
phenomenon,  as  exhibited  by  the  cat,  and  by 
other  animals  covered  with  a  soft  fur,  is  daily 
observed.  But  it  has  been  stated  that  the  cat's 
electricity  may  be  accumulated  in  its  own  body 
and  given  off  suddenly,  so  as  to  produce  a 
shock.  Romer  says,*  "  If  one  take  a  cat  in  his 
lap,  in  dry  weather,  and  apply  the  left  hand 
to  its  breast,  while  with  the  right  he  strokes 
its  back,  at  first  he  obtains  only  a  few  sparks 
from  the  hair;  but,  after  continuing  to  stroke 
for  some  time,  he  receives  a  sharp  shock,  which 
is  often  felt  above  the  wrists  of  both  arms.  At 
the  same  moment,  the  animal  runs  off  with 
expressions  of  terror,  and  will  seldom  submit 
itself  to  a  second  experiment."  In  repeating 
this  experiment,  we  have  obtained  the  like 
result. 

We  are  not  aware  of  any  other  observer  having 
met  with  any  thing  resembling  an  accumulation 
of  electricity  in  quadrupeds,  excepting  Cotugno, 
who  asserted  that,  in  dissecting  a  living  mouse, 
lie  felt  an  electric  shock  when  its  tail  touched 
his  finger.f 

XL  Uses  of  animal  electricity. — The  pur- 
pose which  the  electrical  function  is  fitted 
to  serve  in  the  animal  economy  is  proba- 
bly not  single.  It  is  very  evident  that  the 
discharge  from  the  organs  frequently  strikes 
terror  into  the  enemies  of  their  possessors,  and 
thus  it  may  be  regarded  as  a  means  of  defence; 
while,  in  certain  circumstances,  it  may  be  useful 
in  enabling  the  fish  more  easily  to  secure  its 
prey.  But  this,  probably,  is  not  all.  It  is 
very  likely,  as  Dr.  Roget  has  suggested,!  that 
the  electrical  organs  communicate  to  the  fish 
perceptions  of  electrical  states  and  changes  in 
surrounding  bodies,  (very  different  from  any 
that  we  can  feel,)  in  the  same  way  as  other 
organs  of  sense  convey  perceptions  with  regard 

*  Gilbert's  Ann.  der  Phys.  B.  xvii. 
t  Humboldt.    Ueber  die  gereii-te    Musk-ei-uttd- ' 
Nervenfaser.    Berlin,  1793.  i.  30. 

t  Bridgewater  Treatise,  i,  31.             ,      \  L 
VOL.  II.  J'      V  v   ,.  - — 


to  light  and  sound.  Such  perceptions  we  carl 
conceive  to  be  very  useful  and  pleasurable  to 
animals  living  in  the  dark  abysses  of  the  waters. 

Some  of  Dr.  John  Davy's  observations  make 
it  very  doubtful  whether  the  electrical  function 
is  ever  subservient  to  that  of  prehension  of  food. 
He  kept  young  torpedos  for  a  period  of  five 
months  or  more,  in  large  jars  of  salt  water, 
during  which  time  they  ate  nothing,  although 
very  small  fishes,  both  dead  and  alive,  were  put 
into  the  water.  Yet  they  grew,  and  their  elec- 
trical energies  and  general  activity  increased.* 
The  small  fishes  seemed  to  have  no  dread  of  the 
torpedos.  On  one  occasion,  however,  when  a 
lively  torpedo  was  placed  in  a  small  vessel 
along  with  a  smelt,  and  excited  to  discharge, 
the  smelt  was  evidently  alarmed,  and  once  or 
twice,  when  exposed  to  the  shock,  leaped  nearly 
out  of  the  vessel,  but  it  was  not  injured  by  the 
electricity.  It  has  also  been  frequently  ob- 
served of  the  gymnotus  that  it  eats  very  few  of 
the  fishes  that  it  kills  by  its  discharge. 

The  electrical  power  of  the  young  fish  is 
proportionally  very  much  greater  than  that  of 
the  old,  and  can  be  exerted  without  exhaus- 
tion and  loss  of  life  much  more  frequently. 
After  a  few  shocks,  most  of  the  old  fish  which 
Dr.  Davy  has  endeavoured  to  keep  alive  have 
become  languid,  and  died  in  a  few  hours, 
whilst  young  ones,  from  three  to  six  inches 
long,  remained  active  during  ten  or  fifteen  days, 
and  sometimes  lived  as  many  weeks.  Hence 
Dr.  Davy  concludes  that  the  chief  use  of  the 
electrical  function  is  to  guard  the  fish  from  its 
enemies,  rather  than  to  enable  it  to  destroy  its 
prey,  and  so  provide  itself  with  food.  He  fur- 
ther conjectures  that,  besides  its  defensive  use, 
the  electrical  function  may  serve  also  to  assist 
in  respiration  by  effecting  the  decomposition  of 
the  surrounding  water,  and  so  supplying  the 
gills  with  air  when  the  fish  is  lying  covered 
with  mud  or  sand,  in  which  it  is  easy  to  con- 
ceive that  pure  air  may  be  deficient.  And  Dr. 
Davy  has  often  imagined  that  he  saw  something 
of  this  kind  going  on.  After  repeated  dis- 
charges, he  has  observed,  all  around  the  margin 
of  the  pectoral  fins,  an  appearance  as  if  very 
minute  bubbles  of  air  were  generated  in  it  and 
confined.  That  this  may  be  one  purpose 
which  the  electrical  function  is  designed  to 
serve,  is  rendered  still  more  probable  by  the 
circumstance,  that  the  gills  (in  the  torpedo  at 
least)  are  largely  supplied  with  twigs  of  the 
electrical  nerves.  In  fishes  in  which  he  had 
cut  the  electrical  nerves,  Dr.  Davy  found  the 
secretion  of  the  cutaneous  mucus  considerably 
diminished  or  altogether  arrested ;  and  hence 
he  supposes  that  the  electricity  assists  in  the 
production  of  this  fluid. 

Lastly,  it  has  been  conjectured  that  the  elec- 
trical function  is  subservient  to  that  of  digestion. 
This  idea  was  started  by  Mr.  J.  Couch  some 
years  ago.f  He  says,  "  Without  denying  that 
the  torpedo  may  devour  that  which  it  disables 
by  the  shock,  I  conceive  that  the  principal  use 
of  this  power  has  a  reference  to  the  functions  of 

-J  Phil.  Trans.  1835. 
>">   s  j      N^Jiinn.  Trans,  xiv.  89. 

 «-'.    {  '   A"***  H 


/  1 


98 


NDOSMOSIS. 


digestion.  It  is  well  known  that  an  effect  of 
lightning  or  the  electric  shock  is  to  deprive 
animated  bodies  very  suddenly  of  their  irrita- 
bility ;  and  that  thereby  they  are  rendered  more 
readily  disposed  to  pass  into  a  state  of  disso- 
lution than  they  would  otherwise  be;  in  which 
condition  the  digestive  powers  of  the  stomach 
can  be  much  more  speedily  and  effectually 
exerted  on  them.  If  any  creature  may  seem 
to  require  such  a  preparation  of  the  food  more 
than  another,  it  is  the  torpedo,  the  whole  intes- 
tinal canal  of  which  is  not  more  than  half  as 
long  as  the  stomach." 

These  views  receive  some  support  from  the 
fact  that  the  nerves  of  the  stomach  are  derived 
from  those  supplying  the  electrical  organs ;  and 
perhaps  also  from  the  fact,  reported  by  Dr. 
Davy  regarding  a  torpedo,  in  which,  after  it  had 
been  frequently  excited  to  give  shocks,  diges- 
tion seemed  to  be  completely  arrested. 

The  only  conclusion  to  which,  in  the  present 
state  of  our  knowledge,  we  can  come  on  this 
point  is,  that  although  the  electrical  organs  form 
a  very  efficient  means  of  defence  from  their 
enemies  for  the  fishes  which  possess  them,  this 
is  not  the  only  purpose  they  are  intended  to 
serve  ;  what,  however,  their  other  uses  are  is  at 
present  only  matter  of  conjecture. 

There  remains  yet  unentered  upon  a  large 
field  of  enquiry  connected  with  the  physiology 
of  those  wonderful  organs,  which,  we  doubt 
not,  will  yield  to  future  ages  very  striking 
examples  of  that  nice  and  close  adaptation  of 
means  to  ends  which  so  clearly  proves  to  us  the 
existence  and  continued  exercise  of  Wisdom 
Supreme,  "  upholding  all  things  by  the  word  of 
his  power,"  making  the  smallest  of  his  works 
"  very  good,"  and  "  to  be  thought  upon." 

Bibliography.—  Volta,  Memorie  sull'  elettri- 
cita  animali,  1782.  Gahani,  Dell'  uso  e  dell'  at- 
tivita  dell'  arco  conduttore  nelle  contrazioni  dei 
moscoli.  Bologna,  1794.  Ejus.  Memorie  sull' 
elettricita  animate,  Bologn.  1797.  Fowler,  Expe- 
riments and  Observations  relative  to  the  influence 
called  animal  electricity.  Lond.  1793.  Aldini, 
Essai  Theorique  et  experimental  sur  le  Galvanisme, 
et  in  Bulletin  des  sciences,  an  xi..  No.  68.  Pfaff, 
Ueber  thierische  Elettricitiit  und  Reizburkeit. 
Leipzig,  1795.  Humboldt,  Versuche  iiber  die  ge- 
reizte  Muskel  und  Nervenfaser.  Berlin,  1797. 
Treviranus,  Biologie.  Tiedemann,  Physiologic 
M'uller,  Physiologie.  Carus,  Anat.  Comp.  French 
ed.  t.  i.  Lorenzini,  Osservazioni  interno  alle  tor- 
pedini,  Flor.  1678.  Walsh,  Phil.  Trans.  1774. 
Pringle  on  the  Torpedo,  Lond.  1783.  higenhousz, 
Phil.  Trans.  1775.  Hunter,  Phil.  Trans,  t.  lxiii. 
et  lxv.  Geoffrey  Saint  Hilaire,  Ann.  du  Mns.  t.  i. 
Humboldt,  Kecueil  d'observ.  de  zoologie  et  d'anat. 
comp.  Knox,  Edin.  Journal  of  Science,  1824. 
Todd,  Phil. Trans.  1816.  Davy,  Phil.  Trans.  1834. 
Majendie  and  Desmoulins,  Anat.  des  Systemes  Nerv. 
t.  ii.  Rudolphi,  Abhandl.  der  Acad,  der  Wissen- 
schaft  in  Berlin,  1820.  Becquerel,  Tiaite  d'Elec- 
tricite  et  Galvanism,  t.  iv.  Par.  1836. 

(John  Coldstream. ) 

ENCEPHALON.  In  order  to  lay  before 
the  reader  a  connected  view  of  the  Anatomy  of 
the  Encephalon  in  conjunction  with  that  of  the 
Medulla  Spinalis,  the  Anatomy  of  both  these 
organs  will  be  given  under  the  article  "  Ner- 
vous Centres." 


ENDOSMOSIS,  (ivSov,  intus,  acr^o?,  im- 
pulsus). — Accident  having  made  me  acquainted 
with  the  fact  that  a  small  animal  bladder,  con- 
taining an  organic  fluid,  became  considerably 
distended  by  remaining  for  some  time  plunged 
in  water,  and  that  the  water  even  expelled" the 
thicker  fluid  contained  within  the  bladder,  when 
there  was  a  hole  by  which  it  could  escape,  I  be- 
thought me  of  the  probable  cause  of  this  pheno- 
menon, and  soon  came  to  the  conclusion  that  it 
depended  on  the  difference  of  density  between 
the  included  or  interior  fluid,  and  the  water  or 
exterior  fluid.  I  found  that  the  coeca  of  fowls 
filled  with  milk, thin  syrup,  &c.  and  secured  with 
a  ligature,  became  turgid  and  even  excessively 
distended  when  treated  in  the  same  way.  I  now 
discovered  that  the  fluids  contained  in  the  coeca 
permeated  their  coals,  and  were  diffused  in  the 
surrounding  water.  I  saw,  further,  that  two 
opposite  currents  were  established  through  the 
parietes  of  the  coeca;  the  first  and  stronger 
formed  by  the  exterior  water  flowing  towards 
the  fluid  contained  in  the  coeca;  the  second 
and  weaker,  by  the  thick  included  fluid  flow- 
ing towards  the  water.  To  the  first  of  these 
currents  I  gave  the  name  of  Endosmosis,  and  to 
the  second  that  of  Exosnwsis.  These  titles,  I 
must  allow,  are  objectionable,  and  perhaps 
badly  chosen.  The  first  conveys  the  idea  of  an 
entrance  and  the  second  of  an  exit.  Now,  the 
phenomenon,  regarded  in  its  proper  point  of 
view,  consists  in  a  double  permeation  of  fluids, 
abstracted  from  any  idea  of  entrance  or  exit. 
Besides,  the  current  of  endosmosis,  which, 
etymologically  speaking,  expresses  an  in-going 
current,  may  nevertheless  be,  experimentally 
speaking,  an  out-going  current ;  this,  for  exam- 
ple, happens  when  a  hollow  membranous  organ, 
containing  water,  comes  to  be  placed  in  contact 
exteriorly  with  a  fluid  more  dense  than  water. 
There  is  then  a  current  of  endosmosis  which 
goes  out  of  the  bladder,  and  a  current  of  exos- 
mosis  which  enters  it.  Thus  facts  are  found  in 
contradiction  to  the  terms,  and  these  I  should 
not  have  hesitated  to  change,  if  their  general 
adoption  did  not  render  this  change  very  diffi- 
cult, and  subject  to  great  inconvenience.  I  have, 
therefore,  resolved  to  retain  them,  wishing  it  to 
be  understood  by  naturalists  that  no  attention 
is  here  paid  to  their  etymological  signification. 

To  estimate  the  amount  of  endosmosis  I 
contrived  an  apparatus  to  which  I  gave  the 
name  of  endosmometer ;  it  consists  of  a  small 
bottle,  the  bottom  of  which  is  taken  out,  and 
replaced  by  a  piece  of  bladder.  Into  this  bottle 
I  pour  some  dense  fluid,  and  close  the  neck  with 
a  cork,  through  which  a  glass  tube,  fixed  upon 
a  graduated  scale,  is  passed.  I  then  plunge 
the  bottle,  which  I  entitle  the  reservoir  of'  the 
endosmometer,  into  pure  water,  which,  by  en- 
dosmosis, penetrates  the  bottle  in  various  quan- 
tities through  the  membrane  closing  its  bottom. 
The  dense  fluid  in  the  bottle,  increased  in  quan- 
tity by  this  addition,  rises  in  the  tube  fitted  to 
its  neck,  and  the  velocity  of  its  ascent  becomes 
the  measure  of  the  velocity  of  the  endosmosis. 

To  measure  the  strength  of  endosmosis,  I 
have  made  use  of  an  endosmometer  in  which 
the  tube  was  twice  bent  upon  itself,  the  as- 


ENDOSMOSIS. 


99 


tending  branch  containing  a  column  of  mer- 
cury,* which  was  raised  by  the  interior  fluid 
of  the  §ndosmometer  in  proportion  as  the  en- 
dosmosis, increased  the  volume  of  this  fluid.* 
By  means  of  these  two  instruments  I  have 
foetid  that  the  velocity  and  strength  of  endos- 
mosis  follow  exactly  the  same  law.  Both  are 
m  relation  to  the  quantities  which  express,  in 
two  comparative  experiments,  the  excess  of 
density  of  two  dense  fluids  contained  in  the 
endosmometer,  above  the  density  of  water, 
which  in  these  two  experiments  is  exterior  to 
the  instrument.  Thus,  for  example,  in  putting 
successively  into  the  same  endosmometer,  syrup 
of  which  the  density  is  1.1,  and  syrup  of  which 
the  density  is  1.2,  and  in  plunging  in  both 
cases  the  reservoir  of  the  endosmometer  into 
pure  water,  you  obtain  in  the  first  case  an  en- 
dosmosis,  of  which  the  strength  and  velocity 
are  represented  by  1 ,  and  in  the  second  case  an 
endosmosis,  of  which  the  strength  and  velocity 
are  represented  by  2  ;  that  is  to  say,  by  the 
numbers  relative  to  the  fractionals  0.1  and  0.2, 
which  express  the  excesses  of  density  of  the 
two  solutions  of  sugar  above  the  density  of 
water,  which  is  1.  I  have  ascertained  by  ex- 
periment that  the  strength  of  endosmosis  is 
such  that,  with  syrup  of  which  the  density  is 
1.11,  and  an  endosmometer,  the  opening  of 
which  is  closed  by  three  pieces  of  bladder,  one 
over  the  other,  you  obtain  an  endosmosis  which 
raises  the  mercury  to  1  metre  238  millimetres, 
or  4.5  inches  9  lines,  which  is  equivalent  to  an 
elevation  of  water  of  16  metres  77  centimetres, 
or  51  feet  8  inches.  It  follows  from  this,  that 
in  employing  syrup,  of  which  the  density  was 
1.33,  (its  ordinary  density,)  you  would  obtain 
an  endosmosis,  the  strength  of  which  would  be 
capable  of  raising  water  more  than  150  feet. 

Fluids  of  a  different  nature  have,  with  refer- 
ence to  endosmosis,  properties  which  are  in  no 
way  in  proportion  to  their  respective  densities. 
Thus  sugar-water  and  gum-water  of  the  same 
density,  being  put  successively  into  the  same 
endosmometer,  which  is  plunged  into  pure 
water,  the  former  produces  the  endosmosis 
with  a  velocity  as  17,  and  the  latter  with  a 
velocity  as  8  only.  I  have  seen,  in  the  same 
manner,  a  solution  of  hydrochlorate  of  soda 
and  a  solution  of  sulphate  of  soda  of  the  same 
density,  put  successively  in  the  same  endosmo- 
meter surrounded  with  pure  water;  the  velo- 
city of  the  endosmosis  produced  by  the  solu- 
tion of  sulphate  of  soda  is  exactly  double  that 
of  the  endosmosis  produced  by  the  solution  of 
hydrochlorate  of  soda.  These  results  are  inva- 
riable, and  I  am  persuaded  that  if  1  have  ever 
obtained  a  different  result,  the  experiment  has 
been  defective. 

I  have  made  several  experiments  since  with 
gelatinous  and  albuminous  waters  placed  suc- 
cessively in  the  same  endosmometer,  surround- 
ed with  pure  water,  which  produced  endos- 
mosis severally  in  the  proportion  of  1  to  4  ; 
so  that  the  albumen  had  four  times  more  power 
of  endosmosis  than  the  gelatine.    I  have  seen 

*  See  my  work  entitled,  Nouvelles  Recherches  sur 
l'cndosmose  et  l'exosmose,  &c.  8vo.  Paris,  1828. 


by  another  experiment  that  the  power  of  en- 
dosmosis of  syrup  is  to  the  power  of  endos- 
mosis of  albuminous  water  of  the  same  den- 
sity, as  11  is  to  12. 

All  alkalies  and  soluble  salts  produce  en- 
dosmosis ;  so  do  all  acids,  but  each  with  spe- 
cial phenomena,  which  will  be  noticed  by  and 
by.  These  chemical  agents  in  general  occasion 
an  endosmosis  of  short  duration  only,  when  the 
endosmometer  is  closed  with  a  portion  of  an 
animal  membrane.  Organic  fluids  alone,  which 
are  not  very  sensibly  either  acid  or  alkaline,  or 
salt,  produce  lasting  endosmosis,  which,  in- 
deed, does  not  stop  until  the  fluids  are  altered 
by  putrefaction,  when  they  become  charged 
with  sulphuretted  hydrogen.  I  have  shown  that 
when  an  endosmometer  is  closed  with  a  thin 
plate  of  baked  clay  instead  of  the  animal  mem- 
brane, the  endosmosis  which  a  saline  solution 
produces,  and  which  would  have  stopped  in  a 
few  hours  with  the  animal  membrane,  continues 
to  go  on  indefinitely  with  the  baked  clay. 

The  property  of  destroying  endosmosis  may 
be  considered  as  belonging  to  all  chemical  re- 
agents, but  merely  on  account  of  their  sus- 
ceptibility to  enter  into  combination  with  the 
permeable  partition  of  the  endosmometer.  Thus 
all  acids,  alkalies,  soluble  salts,  alcohol,  &c. 
being  disposed  to  combine  with  the  elements  of 
organic  membranes,  destroy  endosmosis,  al- 
though they  had  induced  it  before  their  complete 
combination  with  the  elements  of  the  membrane 
had  taken  place  ;  and  it  is  not  until  this  combi- 
nation is  complete  that  endosmosis  ceases.  Or- 
ganic fluids,  which  have  no  chemical  action  upon 
the  elements  of  the  membrane  of  the  endosmo- 
meter, ought  not,  consequently,  to  tend  to  the 
destruction  of  endosmosis,  unless  some  change 
should  take  place  which  should  give  them  a 
chemical  action,  such  as  they  usually  acquire 
by  decomposition,  when  they  usually  become 
charged  with  sulphuretted  hydrogen. 

My  earlier  experiments  tended  to  show  that 
carbonate  of  lime  (chuux  carbonatee )  reduced 
to  thin  laminje,  and  employed  to  close  an  en- 
dosmometer, is  totally  without  the  power  of 
producing  endosmosis ;  my  latter  experiments 
have  somewhat  modified  this  conclusion.  After 
having  vainly  employed  lamhrae  of  carbonate 
of  lime  of  greater  or  less  thickness,  I  finished 
.by  making  use  of  one  of  white  marble,  two 
millimetres  in  thickness,  but  with  no  better 
success.  Without  carrying  my  experiments 
further,  I  concluded  that  porous  carbonate  of 
lime  was  totally  unapt  to  excite  endosmosis. 
This  conclusion  having,  notwithstanding,  left 
some  doubts  in  my  mind,  I  again  took  the  same 
plate  of  marble  with  the  intention  of  measuring- 
its  permeability  to  water,  compared  with  the 
various  degrees  of  thickness  which  I  could  give 
it,  and  of  renewing,  at  the  same  time,  my  at- 
tempts to  make  it  produce  endosmosis.  Having 
closed  an  endosmometer  with  this  plate  of  mar- 
ble, I  filled  the  reservoir  and  the  tube  of  the 
instrument  with  pure  water,  and  suspended  it 
over  a  vessel  filled  with  water, in  which  the  plate 
of  marble  only  was  immersed.  If  the  marble 
had  been  permeable  to  water,  the  fluid  con- 
tained in  the  endosmometer  would  have  flowed 

h  2 


100 


ENDOSMOSIS. 


through  the  capillary  conduits  of  the  plate,  and 
this  flow  would  have  become  perceptible  by 
the  sinking  of  the  water  in  the  tube,  the  inte- 
rior of  which  was  only  two  millimeters  in  dia- 
meter. 

The  result  of  this  experiment  was  that  the 
plate  of  marble,  which  was  four  centimeters  in 
diameter,  did  not  lose  by  filtration,  in  one 
day,  more  than  the  small  quantity  of  water 
capable,  by  its  subtraction,  of  lowering  its 
level  one  millimeter  and  a  half  in  the  tube. 
I  next  tried  syrup  in  this  endosmometer,  the 
reservoir  being  plunged  into  pure  water ;  but 
no  endosmosis  was  induced.  I  now  reduced 
the  thickness  of  the  plate  of  marble  to  one 
millimeter  and  a  half;  in  this  state  it  lost  by 
filtration,  in  the  course  of  a  day,  eleven  mil- 
limeters of  water  measured  by  the  tube.  The 
permeability  of  this  plate  was,  as  may  be  per- 
ceived, very  sensibly  increased  :  still  the  en- 
dosmometer which  it  closed  when  filled  with 
syrup  showed  no  indications  of  endosmosis. 
1  reduced  the  thickness  of  the  plate  of  marble 
to  one  millimeter.  In  this  state  it  lost  by  fil- 
tration, in  the  space  of  a  day,  twenty-one  milli- 
meters of  water  measured  in  the  tube.  I  put 
into  the  endosmometer,  which  this  plate  of 
marble  closed,  the  same  syrup  which  had  been 
used  in  the  preceding  experiments,  and  the 
density  of  which  was  1.12,  and  I  now  ob- 
tained an  endosmosis  which  manifested  itself 
by  an  ascension  of  seven  millimeters  in  four- 
and-twenty  hours.  This  last  experiment  proved 
'  to  me  that  carbonate  of  lime  was  not,  as  I  had 
hitherto  found  it,  totally  without  the  power  to 
produce  endosmosis.  1  wished  to  compare 
this  plate  of  marble  with  a  piece  of  bladder  of 
the  same  surface  under  the  double  point  of 
view,  of  their  permeability,  and  their  respec- 
tive properties  of  producing  endosmosis.  Having 
therefore  taken  off  the  plate  of  marble  which 
closed  the  endosmometer,  I  replaced  it  by  a 
piece  of  bladder  whose  permeability  to  water  I 
measured  in  the  same  manner  as  above.  1  found 
this  permeability  very  nearly  equal  to  that  of 
the  plate  of  marble  of  one  millimeter  in  thick- 
ness. I  then  put  into  this  endosmometer 
some  syrup  similar  in  density  to  that  which  I 
had  used  in  the  same  endosmometer  closed 
with  the  plate  of  marble.  The  endosmosis 
which  I  obtained  raised  the  syrup  seventy-three 
millimeters  in  three  hours.  Thus  the  permea- 
bility to  water  being  equal  in  the  bladder  and 
in  the  plate  of  marble,  the  endosmosis  pro- 
duced by  the  first  was  to  the  endosmosis  pro- 
duced by  the  second  as  584  is  to  7,  a  most 
extraordinary  difference,  and  difficult  to  be 
accounted  for.  These  experiments  prove  that 
carbonate  of  lime  is  but  very  little  apt  to  pro- 
duce endosmosis,  in  which  it  differs  singularly 
from  baked  clay,  thin  laminaB  of  which  are 
almost  as  apt  to  produce  endosmosis  as  organic 
membranes. 

The  varieties  of  sulphate  of  lime  which  may 
be  employed  in  endosmometrical  experiments 
are  not  sufficiently  numerous  or  of  sufficient 
variety  of  permeability  for  it  to  be  possible  to 
appreciate  the  properties  of  this  substance  in 
relation  to  endosmosis.    I  found  that  the  sul- 


phate of  lime  used  in  the  manufacture  of 
plaster  in  the  environs  of  Paris,  employed  in 
thin  plates  to  close  an  endosmometer,  did  not 
produce  endosmosis.  But  this  mineral  is  per- 
haps too  easily  permeable.  In  fact  it  is  found 
impossible  to  obtain  endosmosis  when  the  in- 
terior fluid  of  the  endosmometer  flows  easily 
by  filtration,  in  virtue  of  its  weight,  through 
porous  plates.  I  should  say  as  much  of  plates 
of  freestone  ( gres)  which  I  have  employed 
without  success  in  these  experiments,  but  that 
I  recollect  to  have  obtained  the  phenomenon 
in  a  very  slight  degree  with  a  plate  of  freestone 
very  close-grained  and  very  little  permeable  to 
fluids. 

I  have  tried  a  variety  of  experiments  shew- 
ing that  an  increase  of  temperature  increases 
endosmosis.  This  result  has  been  confirmed 
by  repeated  experiments. 

The  quantity  of  the  same  fluid  introduced 
by  endosmosis,  and  with  the  same  sort  of  per- 
meable partition,  is  generally  in  proportion  to 
the  extent  of  surface  of  this  partition.  The 
following  experiment  demonstrated  this  fact. 
I  took  two  endosmometers,  the  membranes  of 
which,  taken  from  the  same  bladder,  were  of 
diameters  in  the  relation  of  one  to  two;  I  filled 
the  reservoirs  of  these  two  endosmometers  with 
syrup  of  equal  density,  and  then  plunged  them 
into  pure  water.  I  had  taken  care  to  weigh 
them  previously  with  great  exactness.  After 
continuing  the  experiment  for  two  hours,  I 
weighed  the  instruments  afresh,  and  found  in 
the  large  endosmometer  four  times  as  great  an 
increase  of  weight  as  in  the  small  one,  which 
proved  that  the  first  had  introduced,  by  endos- 
mosis, four  times  as  much  water  as  the  second. 
This  relation  was  exactly  that  of  the  extent  of 
surface  of  their  respective  membranes,  the 
diameters  of  which  were  as  one  is  to  two,  and 
their  surfaces  consequently  as  one  is  to  four. 

1  have  thus  enumerated  the  effects;  let  us 
now  endeavour  to  ascertain  their  causes. 

The  first  idea  which  presented  itself  to  my 
mind  to  explain  the  phenomenon  of  endosmosis 
was  that  it  was  owing  to  electricity.  We  know 
that  effects  exactly  similar  to  those  of  endos- 
mosis are  produced  by  means  of  the  electricity 
of  the  voltaic  pile  in  the  experiment  of  M. 
Porret,  inserted  in  the  Annates  de  Chirnie, 
vol.  xi.  p.  137.  This  naturalist  having  divided 
a  vessel  into  two  compartments  by  a  septum  of 
bladder,  filled  one  of  the  compartments  with 
water,  and  put  only  a  small  quantity  in  the 
other.  Havmg  placed  the  positive  pole  of  the 
pile  in  communication  with  the  compartment 
full  of  water,  and  the  negative  pole  with  the 
compartment  containing  little  water,  the  fluid 
was  forced  through  the  bladder  from  the  full 
compartment  into  the  almost  empty  one,  and 
there  rose  to  a  higher  level  than  that  to  which 
it  was  reduced  in  the  original  full  compart- 
ment. 

I  varied  this  experiment  by  applying  it  to  my 
own  apparatus.  I  put  pure  water  into  an 
endosmometer,  the  membrane  of  which  was 
plunged  into  water.  I  made  the  interior  water 
of  the  endosmometer  communicate  with  the 
negative  pole  of  the  pile,  and  the  exterior 


END0SM0S1S. 


101 


water  with  the  positive  pole.  I  soon  saw  the 
water  rise  in  the  tube  of  the  instrument :  en- 
dosmosis  had  taken  place.  The  similarity  of 
effects  led  me  to  admit  that  some  particular 
and  unknown  mode  or  form  of  electricity  was 
the  cause  of  the  endosmosis  produced  by  the 
heterogeneous  nature  of  fluids.  It  was  in 
vain,  however,  that  I  tried  to  discover  signs  of 
this  electricity  with  the  most  delicate  electro- 
meters. 

In  reflecting  afterwards  upon  what  might  be 
the  common  cause  of  the  phenomenon  pre- 
sented in  Porret's  experiment  and  that  of  or- 
dinary endosmosis,  I  was  inclined  to  think 
that  electricity  might  not  be  the  immediate 
cause  of  the  effects  exhibited,  and  that  it  only 
acted  in  the  case  cited  by  producing  heteroge- 
neousness  of  quality  in  the  two  fluids  subjected 
to  the  positive  and  negative  poles.  Experience 
seems  to  have  confirmed  my  doubts  on  this 
point.  I  took  a  small  endosmometer  of  glass, 
closed  by  a  piece  of  bladder,  and  filled  its  re- 
servoir with  water  coloured  blue  with  the  co- 
louring matter  of  violets;  I  plunged  the  reser- 
voir of  this  endosmometer  into  the  same  co- 
loured water  contained  in  a  small  glass  vessel ; 
I  put  this  latter  fluid  in  communication  with 
the  positive  pole  of  the  voltaic  pile,  and  the 
interior  fluid  of  the  endosmometer  in  commu- 
nication with  the  negative  pole.  The  exterior 
blue  fluid  soon  became  red,  and  consequently 
acid,  and  the  interior  blue  fluid  became  green, 
and  consequently  alkaline.  These  two  fluids 
having  thus  become  heterogeneous,  to  this  may 
be  ascribed  the  endosmosis  which  manifested 
itself,  and  which  increased  the  volume  of  the 
interior  fluid  at  the  expense  of  the  volume  of 
the  exterior  fluid.  Thus  electricity  would  not 
be  in  this  case  the  immediate  cause  of  endos- 
mosis, but  the  remote  one  ;  it  would  only  act 
in  producing  the  heterogeneous  quality  in  the 
two  fluids,  and  it  would  be  this  quality  which 
would  produce  the  passage  of  fluids  as  in  the 
experiments  on  endosmosis,  the  discovery  of 
which  belongs  to  me. 

But  let  us  now  inquire  in  what  way  hetero- 
geneousness  of  quality  in  two  fluids,  separated 
by  a  membranous  partition,  occasions  the  phe- 
nomenon of  endosmosis.  Upon  this  point 
opinions  are  greatly  divided.  M.  Poisson  and 
Mr.  Power  have  each,  in  his  own  way,  given 
an  analytical  explanation  of  the  phenomenon, 
and  ascribed  it  to  the  action  of  the  capillary 
canals  of  the  porous  septum  interposed  be- 
tween»the  two  fluids.  In  this  explanation  the 
phenomenon  of  the  current  of  exosmosis  is  set 
aside,  or  regarded  as  occurring  merely  acciden- 
tally. Now  this  is  entirely  opposed  to  the  fact, 
— we  have  constantly  evidence  of  the  simulta- 
neous existence  of  the  two  opposite  and  une- 
qual currents  of  endosmosis  and  exosmosis. 

Endosmosis  by  others  has  been  held  to  be 
simply  the  effect  of  the  viscidity  of  one  of  the 
fluids  divided  by  a  porous  septum.  This  visci- 
dity prevents  the  upper  fluid  from  permeating 
the  interposed  septum,  whilst  the  inferior  fluid, 
little  or  not  at  all  viscid,  filters  readily  through 
the  septum  and  mingles  with  the  upper  fluid, 


whose  volume  it  consequently  increases.  This 
opinion,  published  by  a  man  of  distinction,  de- 
serves to  be  seriously  investigated. 

When  an  equal  weight  of  gum  arabic  and  of 
sugar  is  dissolved  in  two  equal  weights  of  water, 
the  viscidity  of  the  different  solutions  is  by  no 
means  the  same,  the  solution  of  the  gum  is  ob- 
viously more  viscid  than  that  of  the  sugar. 
Now  if  these  two  solutions  be  divided  by  a 
piece  of  bladder,  the  current  of  endosmosis 
will  be  found  to  flow  from  the  solution  of  the 
gum  towards  that  of  the  sugar  ;  in  other  words, 
from  the  more  viscid  to  the  less  viscid  fluid; 
in  this  instance,  consequently,  we  see  the  more- 
viscid  fluid  permeating  the  membrane  with 
greater  facility  or  in  greater  quantity, than  the1 
less  viscid  fluid.  More  than  this,  the  same 
phenomenon  takes  place  if  the  quantity  of  the 
gum  be  made  double  that  of  the  sugar.  I  have, 
for  instance,  tried  a  solution  of  two  parts  of 
gum  arabic  in  thirty-two  parts  of  water,  (den- 
sity 1.023,)  and  a  solution  of  one  part  of  sugar 
in  the  same  quantity  of  the  menstruum,  (den- 
sity 1.01-1,)  divided  by  a  piece  of  bladder,  and 
found  that  the  endosmotic  current  was  still 
directed  from  the  solution  of  the  gum  towards 
that  of  the  sugar.  These  facts  suffice  to  prove- 
that  the  endosmotic  current  does  not  always 
flow  from  the  less  towards  the  more  viscid 
fluid.  It  is  not,  therefore,  the  inequality  of 
vicosity  in  these  two  fluids  which  is,  in  this 
instance,  the  cause  of  their  unequal  permeation 
across  the  porous  lamina  which  separates  them. 

In  order  to  place  these  facts  beyond  a  doubt, 
the  comparative  viscidity  of  the  gum-water  and 
the  sugar-water  which  were  made  use  of  in  the 
experiments  of  which  I  have  been  speaking, 
required  to  be  accurately  measured.  Such  a 
comparative  estimate  of  the  viscidity  of  fluids 
may  be  obtained  by  observing  the  time  which 
an  equal  quantity  of  each  of  them,  at  the  same 
temperature,  takes  to  run  through  a  glass  capil- 
lary tube.  In  this  way  I  tried,  1st,  pure  water; 
2d,  a  solution  of  one  part  of  sugar  in  thirty-two 
parts  of  water;  3d,  a  solution  of  one  part  of 
gum-arabic  in  thirty-two  parts  of  water;  4th,  and 
lastly,  a  solution  of  two  parts  of  gum  in  thirty- 
two  of  water.  With  a  temperature  of  +7°  cent. 
I  found  that  fifteen  centilitres  of  pure  water 
passed  through  a  capillary  tube  of  glass  in  one 
hundred  and  fifty-seven  seconds;  that  fifteen 
centilitres  of  the  solution  of  one  part  of  sugar 
in  thirty-two  of  water  passed  through  the  same 
tube  in  one  hundred  and  fifty-nine  seconds  and 
a  half ;  that  fifteen  centilitres  of  the  solution  of 
one  part  of  gum  in  thirty-two  of  water  passed 
through  in  two  bundled  and  sixty-two  seconds 
and  one-third  ;  and  that  the  same  quantity  of 
the  solution  of  two  parts  of  gum  in  thirty-two 
of  water  required  three  hundred  and  twenty-six 
seconds  to  pass  through. 

From  these  experiments  it  appears  that  the 
viscidity  of  the  solution  of  sua;ar,  in  the  propor- 
tion of  one  to  thirty-two  of  water,  (density 
1.014,)  is  very  little  above  that  of  pure  water; 
that  the  viscidity  of  the  solution  of  gum-arabic, 
in  the  proportion  of  one  to  thirty-two  of  water, 
is  much  greater  than  that  of  the  sugared  water 


102 


ENDOSMOSIS. 


just  mentioned  ;  and  finally,  that  the  viscidity 
of  the  gum-water,  containing  two  parts  of  gum 
to  thirty-two  of  water,  (density  1.023,)  is  twice 
as  viscid  as  the  solution  of  sugar  employed. 

It  seems  that  nothing  more  is  wanting  to 
these  proofs  of  the  fact  that  endosmosis  does 
not  depend  on  the  mere  viscidity  of  fluids. 
Nevertheless  I  shall  cite  another  proof  of  this 
truth.  The  very  singular  fact  I  am  about  to 
mention  will  also  prove  that  the  septa  employed 
exert  a  special  influence  on  the  direction  in 
which  endosmosis  takes  place. 

It  is  well  known  that,  in  separating  water 
from  alcohol  by  an  organized  animal  or  vege- 
table membrane,  the  endosmotic  current  flows 
from  the  water  towards  the  alcohol.  I  employed 
oil-silk  (taffetas  go?nme )  or  silk  covered  with  a 
layer  of  caoutchouc,  which  may  be  regarded  as 
equivalent  to  a  thin  lamina  of  elastic  gum,  as 
the  medium  of  separation  between  these  two 
fluids.    During  the  first  thirty-six  hours  of  the 
experiment,  I  observed  an  extremely  slow  en^ 
dosmotic  current  from  the  alcohol  towards  the 
water.    After  this  period  the  endosmosis,  with 
the  same  direction,  became  very  rapid.  This 
increase  in  the  rapidity  of  the  endosmosis  I 
considered  due  to  some  alteration  in  the  caout- 
chouc produced  by  the  action  of  the  alcohol, 
and  in  consequence  of  which  it  became  more 
readily  permeable.    The  endosmotic  current, 
however,  let  it  be  observed,  is  always  from  the 
water  towards  the  alcohol  in  this  experiment, 
instead  of  being  from  the  alcohol  towards  the 
water,  as  is  constantly  the  case  when  the  septum 
between  the  spirit  and  the  water  is  formed  by 
an  organic,  whether  animal  or  vegetable,  tissue. 
We  have  thus  a  clear  demonstration  of  the 
great  influence  possessed  by  the  septum  upon 
the  direction  of  the  current  of  endosmosis.  We 
have,  also,  in  the  instance  just  quoted,  a  proof 
that  the  different  degrees  of  viscidity  of  two 
liquids  plays  no  part  in  the  production  of  this 
phenomenon.    I  would  remark  that  the  endos- 
motic current  carrying  the  alcohol  towards  the 
watey  athwart  the  septum  of  caoutchouc  is  ac- 
companied by  a  counter-current,  which  carries 
the  water  towards  the  alcohol  through  the  same 
septum.    I  assured  myself  that  the  alcohol  had 
received  some  addition  of  water ;  and  yet  it  is 
well  known  that  caoutchouc  is  impermeable  to 
water ;  which  would  seem  to  say  that  the  latter 
fluid  could  only  have  passed  through  the  sep- 
tum of  caoutchouc  by  becoming  mingled  with 
the  alcohol  occupying  the  molecular  interstices 
of  that  substance.    Once  within  these  intersti- 
ces the  alcohol  attracts  the  water  by  the  affinity 
of  mixture,  (a finite  de  mixtion )  and  enables 
it  to  penetrate  the  substance  of  the  caoutchouc, 
which  denies  all  access  to  water  when  it  is 
pure.    It  is  therefore  to  the  state  of  commixtion 
within  the  capillary  tubes  of  the  septum  that  the 
two  opposed  fluids  proceed  the  one  towards 
the  other  with  cross  but  unequal  motions.  The 
means  I  took  to  ascertain  the  fact  of  water 
having  become  mixed  with  the  alcohol  was 
simple  enough  :  I  set  fire  to  a  quantity  of  the 
fluid  which  had  served  for  the  experiment,  and 
found  that,  after  all  the  spirit  had  burned  out, 


a  considerable  quantity  of  water  remained, 
whilst  the  alcohol,  previously  to  being  so  em- 
ployed, burned  away  entirely,  leaving  no  water 
behind  it. 

The  theoretical  views  of  Magnus  in  regard 
to  endosmosis  have  been  adopted  by  Berzelius 
in  his  Chemistry,  and  the  idea  upon  which  they 
are  based  has  been  reproduced  by  M.  Poisson. 
To  give  a  clear  notion  of  this  theory,  let  us  sup- 
pose that  a  measure  of  salt  water  is  separated 
from  a  measure  of  pure  water  by  a  permeable 
septum,  a  piece  of  bladder  for  example ;  the 
current  of  endosmosis,  in  this  instance,  will  be 
from  the  pure  water  towards  the  salt,  and  for 
the  following  reason :  in  the  salt  water  there 
are  three  attractions,  namely,  the  attraction  of 
the  molecules  of  the  water  for  one  another; 
secondly,  the  attraction  of  the  molecules  of  the 
salt  for  one  another;  and  thirdly,  the  reciprocal 
attraction  of  the  molecules  of  the  water  and  of 
the  molecules  of  the  salt.  The  pure  water  on 
the  opposite  side  of  the  septum  again  has  no 
more  than  a  single  form  of  attraction,  to 
wit,  that  of  its  particles  for  one  another.  The 
salt  water  subjected  to  three  attractions  will  be 
moved,  it  may  be  imagined,  with  greater  diffi- 
culty than  the  pure  water,  the  molecules  of 
which  are  obedient  to  but  one  attraction.  Con- 
sequently, in  the  reciprocal  attraction  of  these 
two  fluids,  the  one,  the  molecules  of  which  are 
the  least  subjected  to  attraction  among  them- 
selves, will  make  its  way  with  greatest  rapidity 
athwart  the  capillary  conduits  of  the  dividing 
membrane. 

This  theory  has  a  seducing  aspect,  but  we 
shall  find  immediately  that  it  is  inapplicable  to 
certain  endosmotic  phenomena  presented  by 
acids. 

I  have  shown  above  that  it  is  not  always  to- 
wards the  denser  fluid  that  the  endosmotic  cur- 
rent is  turned.  Thus  alcohol  and  ether  are 
very  much  less  dense  than  water,  and  yet  it  is 
towards  these  fluids  of  inferior  density  that 
water  flows  in  endosmotic  experiments.  Alco- 
hol and  ether  have  this  in  common  with  dense 
fluids  generally,  that  they  rise  to  a  less  height 
in  capillary  tubes  than  water.  From  this  ob- 
servation I  was  led  to  imagine  that  the  endos- 
motic current  was  always  from  the  fluid  having 
the  greatest  power  of  capillary  ascension,  to- 
wards the  fluid  having  the  least  of  this  capa- 
city. It  is  true,  indeed,  as  we  have  already 
seen,  that  alcohol  proceeds  by  endosmosis  to- 
wards water  when  the  medium  dividing  them 
is  caoutchouc.  This  would  seem  to  say  that 
alcohol  would  rise  higher  than  water  in  capil- 
lary tubes  of  caoutchouc;  and  it  is  certain  that 
caoutchouc  has  a  greater  attraction  for  alcohol 
than  for  water,  inasmuch  as  the  surface  of 
India-rubber  is  much  more  readily  wetted  by 
alcohol  than  by  water,  which  only  adheres  to 
it  partially  and  imperfectly.  This  fact,  there- 
fore, would  not  be  in  contradiction  to  my 
theory  ;  although  I  must  confess  that  it  is  not 
reconcilable  with  certain  endosmotic  pheno- 
mena presented  by  the  acids,  as  we  shall  imme- 
diately have  occasion  to  perceive.  In  spite  of 
this,  however,  I  do  not  think  I  ought  to  pass 


ENDOSMOSIS. 


103 


in  silence  all  the  proofs  that  seem  to  establish 
this  theory  upon  a  basis  of  sufficient  solidity  ; 
for  I  cannot  but  perceive  that  it  is  applicable 
to  the  most  general  phenomena  of  endosmosis, 
phenomena,  too,  which  the  acids,  like  all  other 
fluid  bodies,  exhibit,  although  they  also  present 
endosmotic  phenomena  in  addition  of  a  diffe- 
rent nature,  and  which  belong  to  them  exclu- 
sively. 

Inequality  of  density  being  one  cause  of  en- 
dosmosis  among  fluids,  it  became  a  point  with 
me  first  to  ascertain  what  differences  in  power 
of  capillary  ascension  resulted  from  determi- 
nate differences  of  density  among  fluids  ;  and 
next,  to  discover  whether  the  difference  in 
power  of  capillary  ascent  of  two  fluids  bore 
any  constant  ratio  to  the  difference  of  endos- 
mosis  as  it  is  proclaimed  by  experiment. 

The  height  to  which  different  fluids  rise  in 
capillary  tubes  depends  on  a  variety  of  causes, 
in  appearance  very  different,  but  which  must 
have  some  fundamental  analogy.  Of  all  fluids 
water  is  that  which  rises  highest;  and  sub- 
stances held  dissolved  in  it  which  increase  its 
density,  lessen  its  power  of  capillary  ascent, 
which  is  also  diminished  by  increase  of  tempe- 
rature :  hot  water  ascends  a  less  way  in  a  capil- 
lary tube  than  cold  water.  Combustible  fluids, 
such  as  alcohol  and  ether,  are  like  dense  fluids 
in  regard  to  power  of  capillary  ascent ;  so  that 
combustibility  acts  in  the  same  manner  as  den- 
sity in  this  respect.  The  matter  of  which  ca- 
pillary tubes  are  formed  is  also  endowed  with 
the  power  of  modifying  the  capillary  ascent  of 
fluids.  Thus  water,  at  the  same  temperature, 
will  not  rise  to  the  same  height  in  a  series  of 
equal  capillary  tubes  made  of  different  mate- 
rials. These  multiplied  elements,  which  enter 
into  the  determination  of  the  capillary  ascend- 
ing power  of  different  fluids,  render  it  an  ex- 
tremely complicated  phenomenon.  To  simplify 
the  study  of  this  phenomenon  in  the  greatest 
possible  degree,  let  us  confine  ourselves  to  the 
use  of  two  fluids,  namely,  water  and  a  solution 
of  the  hydrochlorate  of  soda.  It  is  easy  to  try 
the  latter  fluid  of  different  densities,  and  to 
compare  the  power  of  capillary  ascent  pos- 
sessed by  each  of  these  with  that  of  pure  water 
at  like  temperatures.  The  same  glass  tube  will 
answer  for  these  comparative  experiments.  Be- 
fore detailing  these  experiments,  however,  I 
have  one  important  remark  to  make,  which  is 
this;  that  the  layer  of  fluid  which  moistens, 
internally,  the  canal  of  a  tube  is  one  of  the 
elements  of  the  capillary  ascension  which  this 
tube  effects.  Thus,  water  will  rise  to  a  de- 
terminate height,  in  a  tube  interiorly  moistened 
with  water ;  but  if  the  interior  of  the  tube  be 
moistened  by  a  saline  solution,  or  by  any  other 
watery  fluid,  or  by  alcohol,  pure  water  will  not 
again  rise  so  high  in  this  tube  as  when  it  was 
moistened  by  water  only.  It  will  be  in  vain 
to  attempt  to  cleanse  the  tube  by  passing  water 
repeatedly  through  it ;  water  will  never  detach 
the  stratum  of  saline  or  other  liquid  which  ad- 
heres to  it,  and  which  diminishes  its  power  of 
producing  capillary  ascension.  To  detach  this 
stratum  of  fluid  you  must  pass  a  filiform  body 
repeatedly  through  the  tube  full  of  water ;  it  is 


only  by  the  rubbing  of  this  body  that  the  stratum 
can  be  detached.  It  must  be  evident  after  this 
observation,  that  in  making  experiments  on  the 
power  of  capillary  ascension  with  various 
fluids  and  with  the  same  tube,  it  is  necessary 
to  cleanse  this  tube  with  great  care  before  each 
experiment;  without  this  we  should  have  de- 
fective results.  We  must  also  take  care  not 
to  warm  the  tube  by  holding  it  between  the 
fingers,  for  if  the  temperature  be  increased  it 
will  no  longer  exert  so  strong  a  capillary  attrac- 
tion. Let  us  now  pass  to  the  detail  of  these 
experiments. 

I  prepared  a  solution  of  hydrochlorate  of 
soda,  the  density  of  which  was  1.12,  the  den- 
sity of  the  water  being  one.  I  took  a  part  of 
this  solution  and  to  it  added  an  equal  volume 
of  water,  which  gave  it  a  density  of  1.06.  I 
had  thus  two  saline  solutions,  of  which  the 
excess  of  density,  above  the  density  of  water, 
was  0.12  and  0.06.  The  excess  was  thus 
in  the  relation  of  two  to  one.  From  my  former 
experiments,  these  two  excesses  ought  to  serve 
as  measures  of  the  endosmosis  produced  by 
each  of  these  saline  solutions,  put  successively 
into  the  same  endosmometer  plunged  in  pure 
water.  In  fact,  having  submitted  both  of  the 
saline  solutions  to  experiment,  I  obtained  from 
the  most  dense  solution  an  endosmosis  exactly 
double  of  that  which  was  produced  by  the  least 
dense  solution.  I  next  inquired  into  the  rela- 
tion existing  between  the  known  density  of  these 
two  saline  solutions  and  water,  and  the  power  of 
capillary  ascension  possessed  by  the  three  fluids. 
I  took  a  glass  tube,  whose  capillary  action 
raised  water  to  the  height  of  12  lines  at  a 
temperature  of  +  10  degrees  It.  (50  Fahrenh.) 
I  found  that  the  same  tube,  at  the  same  tem- 
perature, raised  to  6j  lines  the  solution  of 
hydrochlorate  of  soda,  the  density  of  which 
was  1.12,  and  that  it  raised  to  9^  lines  the 
solution  of  the  same  salt,  the  density  of  which 


was  1.06. 

1.  The  capillary  ascension  of  the  water 
being   ....  12 

The  capillary  ascension  of  the  most 
dense  fluid  being   6 \ 

The  excess  of  the  capillary  ascension 
of  water  is   5 1 

2.  The   capillary  ascension  of  water 
being   ...  12 

The  capillary  ascension  of  the  least 
dense  saline  solution  being   9 1 

The  excess  of  the  capillary  ascension 
of  water  is   2 1 


Thus  the  two  excesses  of  the  capillary  ascen- 
sion of  water  above  the  capillary  ascension  of 
each  of  these  saline  solutions  are  5i|  and  2^,  or 
4|  and  2f.  numbers  which  are  in  the  relation  of 
two  to  one,  as  are  the  two  excesses  0.12  and 
0.06  of  the  density  of  the  two  saline  solutions 
above  the  density  of  water.  Here,  then,  are  two 
saline  solutions  which,  put  separately  in  relation 
to  pure  water,  produce  endosmosis  intherelation 
of  2  to  1.    Shall  we  refer  this  result  to  the 


104 


ENDOSMOSIS. 


circumstance  that  the  excesses  of  density  of 
each  of  these  saline  solutions  over  the  density 
of  water  are  in  the  ratio  of  2  to  1,  or  to  this, 
— that  the  excesses  in  the  power  of  capillary 
ascent  of  each  of  these  saline  solutions  over  the 
power  of  capillary  ascent  of  water  are  in  the 
ratio  of  2  to  1  ?  In  other  words,  is  it  the  re- 
spective density  of  the  two  fluids  which  regu- 
lates or  determines  their  endosmosis,  or  is  it 
the  respective  powers  of  capillary  ascension  of 
the  fluids  severally  ? 

The  following  experiment  will  solve  this 
question.  We  have  seen  above  that  a  solution 
of  sulphate  of  soda  and  a  solution  of  hydro- 
chlorate  of  soda  of  equal  densities  being  put 
in  relation  to  pure  water,  produce  endosmoses 
which  are  in  the  relation  of  two  to  one.  Here 
the  difference  of  density  does  not  interfere  with 
the  regulation  of  the  endosmosis;  we  must  then 
see  if  it  be  regulated  by  the  power  of  capillary 
ascension.  I  prepared  a  solution  of  sulphate 
of  soda  and  one  of  hy  drochlorate  of  soda,  having 
the  same  density  1.085,  and  tested  their  ca- 
pillary ascension  in  the  same  tube  in  which  we 
have  seen  pure  water  raised  to  a  height  of  12 
lines  at  a  temperature  of  +  10  degrees  R. 
I  found  that  in  the  same  tube  and  at  the  same 
temperature  the  capillary  ascension  of  the  so- 
lution of  sulphate  of  soda  was  of  8  lines, 
and  that  of  the  solution  of  hydrochlorate  of 
soda  was  of  10  lines.  The  excess  of  the  capil- 
lary ascension  of  water  above  that  of  the  solu- 
tion of  sulphate  of  soda  is  consequently  4 ; 
the  excess  of  the  capillary  ascension  of  water 
above  the  solution  of  hydrochlorate  of  soda  is 
2.  These  two  excesses  are  in  the  relation  of 
two  to  one,  a  relation  which  also  measures  the 
endosmosis  produced  with  the  concurrence  of 
water  by  each  of  these  two  solutions  of  equal 
density.  The  result  of  this  is  that  the  capillary 
ascension,  or  power  of  capillary  ascent,  of  fluids 
governs  their  endosmosis,  and  that  their  density 
only  intervenes  in  this  case  as  the  determining 
cause  of  their  capillary  ascension.  But  how 
does  the  capillary  action  operate  here  ?  This  ap- 
pears to  be  difficult  to  determine.  The  capillary 
action  never  carries  fluids  out  of  the  canals  in 
which  it  takes  place ;  how  then  apply  this  action 
to  the  phenomenon  of  double  permeation,  which 
takes  place  in  endosmosis  and  exosmosis  ? 
This  double  permeation,  which  carries  two  he- 
terogeneous fluids  towards  each  other,  seems 
as  though  it  were  the  result  of  the  reciprocal 
attraction  of  the  two  fluids,  of  their  tendency 
to  associate  by  admixture.  In  experiments  of 
endosmosis  made  with  a  dense  fluid  and  water, 
the  tendency  to  mix  is  favoured  by  the  respec- 
tive positions  of  the  two  .fluids ;  the  dense 
fluid  is  above  and  the  water  below.  This  dis- 
position may  possibly  be  one  cause  which  fa- 
vours the  reciprocal  mixture  of  the  two  fluids, 
whose  specific  gravity  would  tend  to  place 
them  in  an  inverse  situation  to  that  given  them 
in  the  experiment.  This  does  not  take  place 
when  experiments  on  endosmosis  are  made 
with  alcohol  and  water;  then  the  alcohol,  spe- 
cifically lighter  than  water,  is  situated  above 
this  latter  fluid,  and,  notwithstanding  this,  the 
endosmosis  is  exceedingly  energetic ;  we  must 


then  acknowledge  that  the  specific  gravity  of 
two  fluids  has  not  here  the  degree  of  influence 
that  might  be  supposed  to  belong  to  it  at  first 
sight.  We  have  consequently  no  means  left  to 
explain  the  course  of  the  two  fluids  towards  each 
other  athwart  the  capillary  canals  of  the  parti- 
tion which  separates  them,  but  their  reciprocal 
attraction  or  tendency  to  admixture.  In  ad- 
mitting that  such  is  the  efficient  cause  of  this 
double  permeation  we  must  also  necessarily 
admit  that  this  efficient  cause  is  governed  in 
its  operation  by  the  capillary  action  of  the  par- 
tition. 

Here  another  question  presents  itself, — do 
the  two  fluids  accomplish  their  admixture 
in  the  capillary  canals  themselves,  or  do  they 
cross  the  partition  by  different  capillary  canals, 
so  that  neither  fluid  mixes  with  its  opposite 
fluid  until  the  moment  of  its  exit  from  the 
capillary  canals  ?  On  the  latter  hypothesis  it 
were  necessary  to  admit  that  the  number  and 
diameter  of  the  capillary  canals  followed  sepa- 
rately by  each  of  the  two  fluids  must  be  per- 
fectly equal,  for,  without  that,  how  would  the 
general  result  of  this  double  permeation,  a  result 
which  is  explained  by  the  quantity  of  endosmo- 
sis, be  in  exact  relation  with  the  capillary  action 
on  the  two  fluids  ?  Now  it  is  repugnant  to 
reason  to  admit  any  such  perfect  equality  among 
all  the  capillary  canals,  or  to  suppose  an  equal 
number  especially  fitted  for  the  transmission  of 
each  of  the  two  fluids.  It  must  then  necessarily 
be  allowed  that  the  transmission  of  the  two  op- 
posite fluids  takes  place  by  the  same  capillary 
canals,  and  that  consequently  this  double 
movement  of  transmission  takes  place  by  a 
reciprocal  penetration  of  the  two  fluids. 

The  preceding  theory,  with  which  I  was  at 
one  time  inclined  to  rest  satisfied,  and  which, 
indeed,  seemed  to  be  based  on  a  sufficiently 
firm  foundation,  was  however  brought  into  jeo- 
pardy by  a  discovery  which  I  made  subse- 
quently, in  regard  to  the  phenomena  of  endos- 
mosis exhibited  by  certain  acids  separated 
from  pure  water  by  a  layer  of  animal  mem- 
brane. 

In  the  earliest  experiments  I  made  on  the 
endosmosis  of  the  acids,  I  observed  a  number 
of  anomalous  phenomena,  for  which  I  felt  my- 
self incompetent  to  assign  any  sufficient  reason. 
I  had  always  placed  the  acids  above  the  water, 
from  which  they  were  separated  by  a  layer  of 
animal  membrane.  Certain  acids,  such  as  the 
hydrochloric,  at  very  different  degrees  of  den- 
sity, and  nitric  acid  only  at  pretty  high  degrees 
of  density,  gave  me  an  endosmosis,  the  current 
of  which  was  directed  from  the  inferior  water 
towards  the  superior  acid,  so  that  the  acid  rose 
gradually  in  the  tube  of  the  endosmometer. 
On  the  other  hand,  I  had  always  found  the 
sulphuric  acid  pretty  largely  diluted,  and  the 
hydrosulphuric  acid,  under  the  same  circum- 
stances as  the  acids  mentioned  above,  gradually 
to  sink  in  the  tube  of  the  endosmometer.  I  con- 
cluded from  this  that,  these  acids  did  not  occasion 
any  endosmosis,  and  that  they  passed  mechani- 
cally, and  merely  in  virtue  of  their  gravity, 
athwart  the  animal  membrane  to  mingle  with 
the  water.    I  had  also  found  that  the  sulphuric 


ENDOSMOSIS. 


105 


arid  hydrosulphuric  acids,  added  to  gum-water, 
deprived  it  of  the  faculty  of  producing  endos- 
mosis,  and  that  this  acidulated  water  fell  in  the 
tube  of  the  endosmometer,  instead  of  rising,  as 
simple  gum-water  constantly  does.  These  facts 
induced  me  to  say  metaphorically  that  the  sul- 
phuric and  hydrosulphuric  acids  were  the  ene- 
mies of  endosmosis. 

More  recent  inquiries  have  enabled  me  to 
see  the  above  mentioned  phenomena  in  ano- 
ther light.  It  was  the  oxalic  acid  which  led 
me  to  the  conclusions  I  shall  now  lay  be- 
fore the  reader.  Having  poured  a  solution 
of  this  acid  into  the  endosmometer  closed 
with  a  piece  of  bladder,  and  placed  the  re- 
servoir m  water,  I  found  the  acid  fluid  sink 
rapidly  in  the  tube,  and  flow  towards  the 
inferior  water,  making  its  way  by  filtration 
through  the  animal  membrane.  I  then  reversed 
the  arrangement  observed  in  this  experi- 
ment. I  filled  the  endosmometer  with  water, 
and  plunged  the  reservoir  into  a  solution  of 
oxalic  acid.  I  was  now  surprised  to  find  the 
water  making  its  way  rapidly  into  the  endos- 
mometer, and  the  column  rising  in  the  tube,  so 
that,  in  opposition  to  all  I  had  yet  observed, 
here  was  the  current  of  endosmosis  directed 
from  the  acid  towards  the  water.  The  follow- 
ing are  the  particulars  of  this  experiment. 
Having  poured  some  rain-water  into  the  reser- 
voir of  the  endosmometer,  I  plunged  the  reser- 
voir, closed  with  a  piece  of  bladder,  into  a  so- 
lution of  oxalic  acid  of  the  density  of  1.045, 
(11.6  parts  of  crystallized  acid  in  100  of  the 
solution,)  the  temperature  being  +  25  cent. 
The  ascent  of  the  water  in  the  tube  of  the  en- 
dosmometer lasted  for  three  days,  becoming 
gradually  slower  and  slower.  The  ascent  hav- 
ing then  become  almost  imperceptible,  I  emp- 
tied the  endosmometer,  in  the  contents  of 
which  I  found  water  charged  with  oxalic  acid. 
The  exterior  fluid  was  reduced  in  density  to 
1.033,  so  that,  whilst  the  lower  acid  had  pene- 
trated the  upper  water  by  endosmosis,  the 
water  had  penetrated  the  acid  by  exosmosis, 
and  thus  diminished  its  density  ;  the  permea- 
tion of  the  water,  however,  had  been  less  con- 
siderable than  that  of  the  acid  ;  so  that  the 
upper  water,  increased  in  volume,  had  risen  in 
the  tube  of  the  endosmometer.  We  have  thus, 
in  the  present  instance,  another  obvious  proof 
of  the  existence  of  two  opposite  and  unequal 
currents.  Having  filled  the  reservoir  of  the  en- 
dosmometer anew  with  rain-water,  I  placed  it  in 
the  solution  of  oxalic  acid  already  used,  and  of 
the  reduced  density  of  1.033.  The  ascent  in 
the  tube  which  again  occurred,  having  almost 
ceased  at  the  end  of  two  days,  I  tested  the 
fluid  in  the  endosmometer,  and  found  it  to  con- 
tain oxalic  acid, and  discovered  the  density  of  the 
external  fluid  further  reduced  to  1.025.  I  re- 
peated the  same  experiment  a  third  time,  filling 
the  reservoir  of  the  endosmometer  with  rain- 
water, and  plunging  it  in  the  old  acid  solution. 
Endosmosis  went  on  as  before,  but  with  less 
celerity.  Having  given  up  the  experiment,  after 
the  lapse  of  twenty-four  hours  I  found  the 
density  of  the  exterior  fluid  now  reduced  to 
1.023,  and  the  internal  fluid  to  contain  a  por- 


tion of  oxalic  acid  as  before.  I  reduced  the 
densi'y  of  the  exterior  acid  solution  to  1.01, 
but  the  included  water  still  gave  evidence  of  a 
pretty  active  endosmosis.  I  reduced  the  den- 
sity of  the  acid  to  1.005,  (1.2  of  acid  to  100 
of  the  solution,)  and  the  endosmosis  was  still 
very  remarkable.  In  these  experiments  I  found 
that  the  endosmosis  was  by  so  much  the  more 
rapid  as  the  exterior  acid  solution  was  more 
dense,  so  that  the  capacity  of  oxalic  acid  to 
permeate  an  animal  membrane  would  appear 
to  increase  with  the  density  of  its  solution  in 
water.  In  these  experiments,  too,  we  observe 
a  fluid,  more  dense  than  water,  and  having  a 
less  power  of  capillary  ascent  than  it,  never- 
theless forming  the  stronger  current,  or  current 
of  endosmosis,  whilst  the  water  opposed  to  this 
fluid  forms  the  iveukcr  current,  or  counter-cur- 
rent of  exosmosis.  This  is  in  opposition  to  all 
I  had  observed  before ;  and  the  theory  I  had 
raised  on  the  different  capacities  of  capillary 
ascent  possessed  by  two  opposed  fluids  is  con- 
sequently shaken,  or  at  all  events  proved  to  be 
no  longer  generally  applicable.  What  may  be 
the  cause  of  this  new  phenomenon  ?  Do  animal 
membranes  give  passage  more  readily  through 
their  meshes  to  solutions  of  oxalic  acid  than  to 
water  ?  This  point  I  sought  to  determine  by 
the  following  experiments. 

The  filtration  of  a  fluid,  by  virtue  of  its  gra- 
vity, through  a  porous  lamina,  the  capillary 
canals  of  which  are  very  minute,  is  not  readily 
appreciable,  unless  the  inferior  or  outer  surface 
of  this  porous  plate  is  kept  plunged  in  or 
moistened  by  the  same  fluid.  It  is  in  this  way 
only  that  the  filtration  of  fluids  through  animal 
membranes,  the  texture  of  which  is  dense  (a 
piece  of  bladder  for  example,)  becomes  appre- 
ciable. It  is  essential  that  the  inferior  aspect 
of  the  membrane  be  bathed  with  the  same  fluid 
as  that  which  rests  on  its  superior  aspect,  in 
order  that  no  foreign  cause  modify  its  filtration. 
We  know  in  fact  that  the  heterogeneousness  of 
two  fluids,  by  producing  endosmosis,  would 
completely  mask  the  effects  of  simple  filtration. 
Would  I,  then,  try  the  filtration  of  water  through 
a  membrane,  I  apply  this  membrane  to  an  en- 
dosmometer, which  I  fill  with  water  to  a  certain 
height  in  the  tube  of  the  instrument;  I  next 
apply  the  lower  surface  of  this  membrane  to 
the  surface  of  a  body  of  water  placed  below  it. 
The  water  contained  in  the  endosmometer  filters 
through  the  membrane  and  mingles  with  the 
water  in  the  vessel  below;  the  amount  of  this 
filtration  in  a  given  time  is  indicated  by  the 
fall  of  the  column  in  the  graduated  tube  of  the 
instrument.  Would  I  essay  comparatively  the 
filtration  of  any  watery  solution,  I  place  this 
solution  in  the  same  endosmometer,  and  taking 
care  to  keep  the  exterior  of  the  membranous 
part  of  the  instrument  in  contact  with  a  solution 
of  the  same  nature,  situated  below  it,  I  observe 
the  degree  to  which  the  depression  of  the  co- 
lumn in  the  tube  takes  place  in  a  space  of  time 
equal  to  that  which  was  taken  by  the  filtration 
of  the  water.  It  is  necessary  to  begin  by 
proving  the  filtration  of  water;  after  this  the 
filtration  of  the  watery  solution  may  be  tried; 
but  it  is  always  to  be  borne  in  mind  that  the 


106 


ENDOSMOSIS. 


membrane  of  the  endosmometer  must  have 
been  kept  plunged  in  the  watery  solution  about 
to  be  experimented  on  for  at  least  a  quarter  of 
an  hour,  in  order  that  it  may  become  tho- 
roughly impregnated  with  the  solution,  and  to 
secure  that  this  should  take  the  place  of  the 
water  which  the  membrane  had  formerly  con- 
tained in  its  pores.  Without  this  measure  of 
precaution,  the  results  of  the  second  experi- 
ment would  be  faulty.  It  is  also  indispensa- 
ble that  the  circumstances  under  which  the 
two  experiments  are  performed  are  in  all  re- 
spects exactly  alike.  It  was  in  this  way  that  I 
proceeded  to  ascertain  comparatively  the  capa- 
city of  filtration  of  water  to  that  of .  a  watery 
solution  of  oxalic  acid  through  a  piece  of  blad- 
der. I  found  that  the  filtrating  power  of  rain- 
water, at  the  temperature  of  +  21  cent,  being 
denoted  by  24,  the  filtrating  power  of  a  watery 
solution  of  oxalic  acid  of  no  greater  density 
than  1.005,  (1.2  of  acid  to  100  of  solution,)  was 
denoted  by  12.  A  solution  of  the  same  acid,  of 
the  density  of  1 .01 , being  tried,  its  filtrating  power 
was  found  to  be  represented  by  9.  By  these  ex- 
periments it  is  therefore  proved  that  water  tra- 
verses an  animal  membrane  more  readily  than 
a  solution  of  oxalic  acid.  Why  then  does  the 
latter  solution  traverse  an  animal  membrane 
more  readily  and  in  greater  quantity  than  water, 
when  it  is  water  which  is  in  contact  with  the 
surface  of  the  membrane  opposite  to  that  which 
is  in  contact  with  the  acid  ?  This  is  a  question 
which  I  find  it  impossible  to  answer  in  the 
present  state  of  our  knowledge. 

The  discovery  of  this  singular  property  of 
the  oxalic  acid  to  cause  the  endosmotic  current 
to  flow  towards  the  water  when  separated  from 
the  latter  fluid  by  a  lamina  of  ammal  mem- 
brane, led  me  to  imagine  that  all  the  acids 
would  be  found  to  possess  a  similar  property. 
And  this  I  ascertained,  in  the  first  instance,  to 
be  the  case  in  regard  to  the  tartaric  and  citric 
acids.  Both  of  these  acids  are  much  more  so- 
luble in  water  than  oxalic  acid.  The  saturated 
solution  of  oxalic  acid  at  +  25  cent,  has  no 
higher  a  density  than  1.045  (11.6  acid  to  100 
of  the  solution.)  But  the  solubility  of  the  tar- 
taric and  citric  acids  is  such  that  their  watery 
solutions  may  have  a  density  of  far  greater 
amount.  I  tried  the  endosmotic  effects  of  the 
tartaric  and  citric  acids  in  watery  solution  of 
various  density,  and  I  discovered,  not  without 
surprise,  that  very  dense  solutions  of  them  and 
solutions  of  inferior  density  exhibited  endos- 
motic phenomena  in  inverse  ratios.  Thus, 
when  a  solution  of  tartaric  acid  was  of  a  den- 
sity above  1.05,  (11  crystallized  acid  in  100  of 
solution,)  and  it  was  divided  from  water  by  an 
animal  membrane,  the  temperature  being  +  25 
cent,  the  endosmotic  current  is  directed  from 
the  water  towards  the  acid  ;  but  when,  under 
the  same  circumstances,  the  density  of  the  acid 
solution  is  below  1.05,  the  current  of  endos- 
mosis  is  directed  from  the  acid  towards  the 
water,  just  as  we  have  found  it  to  be  with  refe- 
rence to  the  oxalic  acid.  Consequently,  ac- 
cording to  its  greater  or  less  density,  tartaric 
acid  presents  the  phenomenon  of  endosmosis  in 
two  opposite  directions.    At  the  mean  density 


of  1.05,  at  a  temperature  of  ■+•  25°  cent,  it 
exhibits  no  obvious  endosmotic  phenomena 
whatever ;  not  that  there  is  not  reciprocal  pe- 
netration between  the  acid  and  the  water,  which 
are  divided  by  the  animal  membrane  ;  but  this 
reciprocal  penetration  takes  place  so  equally  on 
either  side,  that  there  is  no  increase  of  bulk  of 
the  one  fluid  at  the  cost  of  the  other — there  is 
no  endosmosis.  The  citric  acid  exhibits  pre- 
cisely the  same  phenomena ;  the  point  of  mean 
density,  which  divides  its  two  opposed  endos- 
motic capacities,  is  also  very  nearly  the  same, 
namely,  1 .05  at  a  temperature  of  -\-  25°  cent. 
These  facts  induced  me  to  imagine  that  if  the 
oxalic  acid  alone  presented  the  endosmotic  cur- 
rent directed  from  the  acid  towards  the  water, 
this  arose  from  the  fact  of  its  solution  at  +  25° 
cent,  falling  short  of  the  density  necessary  to 
permit  the  acid  solution  to  cause  the  endosmo- 
tic current  to  flow  from  the  water  towards  the 
acid. 

The  preceding  observations  were  made  during 
the  heats  of  summer.  The  centigrade  thermo- 
meter was  standing  at  +  25°  when  I  determined 
the  mean  term  of  density  of  the  solution  of  tar- 
taric acid,  above  and  short  of  which  the  endos- 
mosis happening  between  this  solution  and 
water  is  directed  towards  the  acid.  ..It  was  of 
importance  to  know  whether  a  depression  of 
temperature  would  cause  any  modification  in 
these  phenomena.  I  therefore  repeated  the 
same  experiments  when  the  temperature  was 
4-15°  cent,  and  I  was  astonished  to  find  that 
the  mean  term  of  density,  of  which  we  have 
spoken  above,  was  considerably  altered,  being 
made  to  move  in  the  direction  of  the  increase 
of  density  of  the  acid  solution.  Thus  the  mean 
term  of  density  being  1.05,  (11  crystallized 
acid  to  100  solution,)  at  a  temperature  of  +  25° 
cent,  it  came  to  be  1.1,  (21  acid  to  100  solu- 
tion,) at  a  temperature  of  +  15°  of  the  same 
scale ;  that  is  to  say,  the  solution  of  tartaric 
acid,  which  now  occupies  the  mean  term,  con- 
tains nearly  twice  as  much  acid  as  the  solution 
which  stood  at  the  previous  mean  term,  when 
the  temperature  was  ten  degrees  of  the  centi- 
grade scale  higher.  This  first  essay  was  enough 
to  lead  to  the  inference  that  the  mean  term  of 
density,  which  we  are  now  discussing,  would 
undergo  further  alterations  in  the  same  sense 
with  further  depressions  of  temperature;  and 
this  was  actually  found  to  be  the  case.  At  a 
temperature  of  8J°  cent,  the  solution  of  tarta- 
ric acid,  of  the  density  1.1,  was  no  longer  the 
solution  of  mean  density  dividing  the  two  op- 
posed endosmotic  currents,  as  it  was  when  the 
temperature  was  +  15°  cent.  This  solution 
then  caused  the  endosmotic  current  to  flow 
freely  towards  the  water.  I  had  to  increase  its 
density  to  1.15  (30  acid  to  100  solution)  to 
come  to  the  new  mean  term,  beyond  which  the 
current  of  endosmosis  was  directed  towards  the 
acid,  and  within  which  it  was  directed  towards 
the  water.  With  the  temperature  depressed  to 
a  quarter  of  a  degree  cent,  above  zero,  the 
solution  of  tartaric  acid,  of  the  density  of  1.15, 
no  longer  presented  the  mean  term ;  this  solution 
now  occasioned  endosmosis  towards  the  water, 
which  indicated  that  the  mean  term  was  to  be 


ENDOSMOSIS. 


107 


sought  for  in  a  more  dense  solution  of  tartaric 
acid,  and  this  I  actually  found  in  a  solution  of 
the  density  of  1.21  (40  acid  to  100  solution). 
Every  solution  of  this  acid  of  greater  density 
than  1.21,  at  the  temperature  of  £th  of  a  degree 
above  zero  cent,  caused  the  endosmotic  cur- 
rent to  flow  from  the  water  towards  the  acid, 
and  every  solution  of  the  same  acid,  under  the 
density  of  1.21,  caused  the  endosmotic  current 
from  the  acid  towards  the  water.    From  all 
these  experiments  it  follows  that  a  fall  of  tem- 
perature favours  the  endosmosis  towards  the 
water,  and  that  a  rise  of  temperature  favours 
the  endosmosis  towards  the  acid.    Jn  fact,  the 
same  solution  of  tartaric  acid  occasions  at  one 
time  endosmosis  towards  the  acid,  when  the 
temperature  is  high ;  at  another,  endosmosis 
towards  the  water  when  the  temperature  is  re- 
latively low.    It  would  appear  from  this,  that 
a  depression  of  temperature  renders  the  solu- 
tion of  tartaric  acid  more  apt  than  water  to 
permeate  animal  membranes,  and  that  there  is 
a  certain  concordance  between  this  capacity  of 
permeation  and  the  temperature  and  the  den- 
sity of  the  acid  solution.    This  phenonemon, 
at  first  sight,  appears  analogous  to  that  which 
M.  Girard  discovered,*  in  regard  to  the  com- 
parative flow  of  a  solution  of  nitre  and  of  pure 
water  through  a  capillary  glass  tube.  M.  Girard 
found  that,  at  a  temperature  of  +10°,  a  solu- 
tion of  one  part  of  nitrate  of  potash  in  three 
parts  of  water  flows  more  rapidly  than  pure 
water  through  a  capillary  glass  tube,  whilst  the 
same  solution  flows  more  slowly  than  water 
when  the  temperature  is  above  -|-  10°.  To 
discover  whether  this  apparent  analogy  was 
well  founded  or  not,  I  made  an  experiment  to 
ascertain  the  relative  duration   of  the  flow 
through  a  capillary  glass  tube  of  a  given  mea- 
sure of  pure  water,  and  a  like  measure  of  a 
solution  of  tartaric  acid,  the  density  of  which 
was  1.05  (21.8  parts  acid,  100  solution.)  The 
temperature  being  +  7°  cent.  I  found  that 
fifteen  centilitres  of  water  flowed  through  a  ca- 
pillary glass  tube  in  157  seconds;  but  the 
same  quantity  of  the  solution  of  tartaric  acid 
required  301  seconds  to  pass  through  the  same 
capillary  tube.    There  is  consequently  no  ac- 
tual analogy  to  be  established  between  the  re- 
sults of  the  experiments  of  M.  Girard  and  the 
fact  of  the  endosmosis  towards  the  water,  which 
takes  place  when  at  a  temperature  of  +7° 
cent,  a  solution  of  tartaric  acid  of  the  den- 
sity of  1.105,  is  separated  from  a  volume  of 
pure  water  by  a  piece  of  an  animal  membrane. 
It  may  be  as  well  if  I  here  state  that  when  a 
solution  of  one  part  of  nitrate  of  potash  in  three 
parts  of  water  was  separated  by  a  piece  of 
bladder  from  pure  water,  I  have  always  ob- 
served the  endosmotic  current  directed  towards 
the  solution ;  the  temperature  might  be  at 
zero,  or -J-  10°,  or  higher,  the  same  phenome- 
non always  occurred.    This  is  sufficient  to 
prove  that  endosmosis  is  governed  by  laws  en- 
tirely different  from  those  that  preside  over 
simple  capillary  filtration.     I  add,  that  the 
solution  of  tartaric  acid,  of  1.105  density,  hav- 

'  Mem.  de  l'Acud.  des  Sciences,  1816. 


ing  a  viscidity  nearly  the  double  of  that  of 
water,  and  passing,  nevertheless,  by  endosmo- 
sis into  the  latter  fluid,  when  it  is  separated 
from  it  by  an  animal  membrane,  and  the  tem- 
perature is  +  7°  cent,  also  proves  that  endos- 
mosis does  not  generally  depend  on  the  visci- 
dity of  fluids. 

Acid  solutions  are  the  only  fluids  which  have 
yet  been  found  to  occasion  the  endosmotic  cur- 
rent to  flow  towards  water  when  separated  from 
this  fluid  by  an  animal  membrane.    The  whole 
of  the  acids,  without  exception,  exhibit  this 
phenomenon,  which  was  long  overlooked  by 
me,  from  its  having  been  confounded  with 
another  phenomenon,  namely,  the  abolition  of 
endosmosis.    I  have  in  fact  shown,  in  a  work 
already  before  the  public,*  that  all  fluids  which 
act  chemically  on  the  membrane  of  the  endos- 
mometer,  put  an  end,  with  greater  or  less  cele- 
rity, to  the  phenomenon  of  endosmosis, — it 
goes  on  for  some  time,  but  it  never  fails  to 
cease  at  length.    Sulphuric  acid,  above  all  the 
other  acids,  has  the  property  of  putting  an  end 
to  endosmosis.    This  acid,  poured  into  the  en- 
dosmometer,  sinks  by  virtue  of  its  simple  gravity 
towards  the  lower  water,  filtering  mechanically 
through  the  membrane  placed  between  it  and 
the  water.    If  the  position  of  the  two  fluids  be 
reversed,  the  endosmometer  being  charged  with 
water,  and  the  sulphuric  acid  placed  externally 
and  on  the  lower  level,  the  water  still  sinks  to- 
wards the  acid,  passing  in  its  turn  mechani- 
cally through  the  membranous  septum  of  the 
instrument,  rendered  incapable  of  effecting  en- 
dosmosis.   From  these  experiments  I  was  led 
at  first  to  conclude  that  sulphuric  acid  was  in- 
active as  regards  endosmosis ;  in  other  words, 
was  incapable  of  exhibiting  or  producing  this 
phenomenon.    I  have  since  found,  however, 
that  the  sulphuric,  like  all  the  other  acids,  has 
the  faculty  of  exerting  endosmosis  in  the  two 
opposite  directions,  but  always  during  a  very 
brief  space  of  time  only.    Thus  the  tempera- 
ture being  +  10°  cent.,  sulphuric  acid,  of  the 
density  of  1.093,  separated  from  water  by  a 
piece  of  bladder,  the  endosmotic  current  is 
directed  from  the  water  towards  the  acid,  but 
the  phenomenon  lasts  only  for  a  short  time ; 
the  current  soon  ceases,  and  if  the  acid  be  on 
the  higher  level,  it  then  begins  to  sink  by  sim- 
ple mechanical  filtration  towards  the  water. 
At  the  same  temperature  of  +  10°  cent.,  the 
sulphuric  acid  attenuated  to  1.054  being  placed 
in  the  endosmometer,  and  the  reservoir  and  a 
part  of  the  tube  being  plunged  in  water,  en- 
dosmosis is  established,  but  in  this  case  the 
current  is  from  the  acid  towards  the  water,  so 
that  the  acid  liquor  sinks  in  the  tube  ;  and  that 
this  sinking  is  due  to  endosmosis  is  demon- 
strated by  the  fact  of  the  acid  continuing  to 
sink  in  the  tube  of  the  endosmometer  a  consi- 
derable way  below  the  level  of  the  external 
water,  and  not  stopping  short  when  the  level  is 
obtained,  as  it  does  when  the  descent  is  owing 
to  simple  mechanical  filtration.    In  this  expe- 
riment, as  in  the  one  detailed  immediately  be- 

*  Nouv.  Redhetches  sur  l'Emlosmose,  &c.  p.  25. 
See  also  my  Memoir  in  the  49th  vol.  of  the  Annates 
de  Chimie,  p.  415. 


108 


ENDOSMOSIS. 


fore  it,  the  endosmosis  towards  the  water  is 
abolished,  and  then  the  column  in  the  endos- 
mometer  begins  to  rise  again  slowly,  until  the 
level  of  the  external  and  included  fluids  corre- 
spond.   We,  therefore,  see  that  at  a  tempera- 
ture of  +  10°  cent.,  sulphuric  acid,  of  the 
density  of  1.093,  presents  the  current  of  endos- 
mosis from  the  water  towards  the  acid  ;  whilst 
the  density  being  1.054,  the  endosmosis  is 
from  the  acid  towards  the  water.  Between 
these  two  opposite  endosmotic  currents  there 
necessarily  exists  a  mean  when  no  phenomena 
of  the  kind  occur.    This  mean,  the  tempera- 
ture continuing     10°,  I  find  to  belong  to  sul- 
phuric acid  of  the  density  of  1.07.    The  two 
fluids,  divided  by  the  animal  membrane  of  the 
endosmometer,  penetrate  one  another  athwart 
the  septum  reciprocally  and  in  equal  measure, 
so  that  the  contents  of  the  endosmometer  re- 
main for  a  certain  time  at  the  same  height  in 
the  tube  of  the  instrument ;  subsequently  the 
contained  fluid  begins  to  sink  in  consequence 
of  the  cessation  of  all  endosmosis.    These  ex- 
periments were  necessarily  undertaken  when 
the  temperature  was  mpderate  or  low ;  the 
phenomena  detailed  would  not  else  have  been 
appreciable ;  for  in  a  warm  atmosphere  the 
abolition  of  endosmosis  by  sulphuric  acid  is 
accomplished  so  rapidly,  that  it  is  with  diffi- 
culty the  slight  current  established  in  the  first 
instance  can  be  observed. 

Sulphurous  acid,  of  the  density  1.02,  sepa- 
rated from  water  by  an  animal  membrane,  only 
exhibits  endosmosis  towards  the  water ;  this 
endosmosis  is  pretty  active  at  first ;  but  after 
the  lapse  of  a  brief  interval  the  current  ceases, 
just  as  it  does  with  the  sulphuric  acid.  These 
results  I  came  to  after  a  number  of  experi- 
ments, the  temperature  being  at  one  time  +  5°, 
and  at  another  +25°  cent. 

Formerly  I  regarded  the  hydrosulphuric  acid 
as  inactive  in  regard  to  endosmosis  ;  I  assimi- 
lated it,  in  this  respect,  with  the  sulphuric  acid. 
The  fact,  however,  is  that,  like  the  sulphuric 
acid,  it  has  the  property  of  producing  endos- 
mosis. The  acid  I  employed  was  of  the  den- 
sity of  1 .00628.  With  a  piece  of  bladder  be- 
tween this  acid  and  water,  the  endosmosis  was 
constantly  towards  the  water.  This  conclusion 
was  not  influenced  by  variations  of  tempera- 
ture between  -j-  4°  and  -f-  25°  cent.  The  ac- 
tion was  somewhat  protracted,  but  the  endos- 
mosis never  failed  to  cease  after  a  certain  time, 
as  in  the  case  of  the  sulphuric  acid. 

The  nitric  acid  of  considerable  density  exhi- 
bits endosmosis  towards  the  acid  when  sepa- 
rated from  water  by  a  piece  of  animal  mem- 
brane. Thus,  at  a  temperature  of  +10°  cent, 
this  acid  (density  1.12  or  higher)  presents  the 
current  flowing  towards  the  acid.  Under  the 
same  circumstances,  but  of  the  density  of  1.08, 
the  endosmosis  is  towards  the  water.  Of  the 
density  1.09,  the  mean  term  between  the  two 
opposite  endosmoses  is  obtained.  At  higher 
temperatures  the  nitric  acid  very  speedily  puts 
an  end  to  the  phenomena  of  endosmosis,  espe- 
cially when  its  density  is  not  very  high,  so  that 
it  becomes  difficult  to  perceive  the  very  tran- 
sient currents  produced  in  the  first  instance. 


The  hydrochloric  is  the  most  potent  of  all 
the  mineral  acids  in  directing  the  current  of 
endosmosis  from  the  water  towards  the  acid. 
Its  density  must  be  considerably  reduced  before 
it.  offers  the  direction  of  the  current  changed,  or 
from  the  acid  towards  the  water.  At  a  tempe- 
rature of  4-  22°  cent,  for  instance,  the  hydro- 
chloric acid  has  to  be  brought,  by  the  addition 
of  water,  to  a  density  no  higher  than  1.003, 
before  it  presents  the  endosmosis  flowing  to- 
wards the  water,  from  which,  as  understood,  it 
is  divided  by  a  layer  of  animal  membrane.  Of 
greater  density  the  endosmosis  is  towards  the 
acid.  When  the  temperature  is  lower  than 
+  22°,  the  same  acid,  of  greater  density,  ac- 
quires the  property  of  causing  endosmosis  to- 
wards the  water.  Thus,  with  the  centigrade 
thermometer  at  +  10°,  I  found  that  hydro- 
chloric acid  of  1.017  density  presented  the 
mean  term  between  the  two  opposite  endosmo- 
ses. At  the  same  temperature  hydrochloric 
acid,  of  1.02  density,  presented  endosmosis  to- 
wards the  acid,  and  of  1.015  density,  endos- 
mosis towards  the  water.  Under  a  higher 
temperature,  however,  and  of  the  latter  density 
(1.015),  the  endosmosis  was  towards  the  water, 
so  that  a  depression  of  12°  cent,  in  tem- 
perature causes  the  mean  term  of  the  density  of 
hydrochloric  acid,  which  separates  the  two  op- 
posed endosmoses,  to  rise  from  that  of  about 
1.003  to  that  of  1.027;  that  is  to  say,  the 
quantity  of  acid  added  to  the  water  must  be 
increased  almost  six-fold  to  produce  the  same 
effects. 

In  the  present  state  of  our  knowledge,  we 
find  it  quite  impossible  to  give  any  explanation 
of  the  remarkable  phenomenon  exhibited  in  the 
changes  of  direction  of  the  endosmotic  currents 
according  to  the  degree  of  density  of  the  acid 
and  the  temperature.  The  singularity  of  this 
phenomenon  will  appear  the  greater  when  the 
following  observation  is  taken  into  the  account. 
Hitherto  it  was  always  by  a  layer  of  animal 
membrane  that  I  separated  the  acid  from  the 
water.  Instead  of  the  animal  membrane  I 
now  tried  the  effect  of  one  of  vegetable  origin. 
We  have  seen  above  that  oxalic  acid,  whatever 
its  density  and  under  whatever  temperature, 
when  separated  from  water  by  an  animal  mem- 
brane, always  exhibited  endosmosis  from  the 
acid  towards  the  water.  I  filled  a  pod  of  the 
colutea  arborexcens,  which  being  opened  at  one 
end  only  and  forming  a  little  bag,  was  readily 
attached  by  means  of  a  ligature  to  a  glass  tube, 
with  a  solution  of  oxalic  acid,  and  having 
plunged  it  into  rain-water,  endosmosis  was  ma- 
nifested by  the  ascent  of  the  contained  acid 
fluid  in  the  tube ;  that  is  to  say,  the  current 
flowed  from  the  water  towards  the  acid.  The 
lower  part  of  the  leek  ( allium  porrum )  is  en- 
veloped or  sheathed  by  the  tubular  petioles  of 
the  leaves.  By  slitting  these  cylindrical  tubes 
down  one  side,  vegetable  membranous  webs,  of 
sufficient  breadth  and  strength  to  be  tied  upon 
the  reservoir  of  an  endosmometer,  are  readily 
obtained.  An  endosmometer,  fitted  with  one 
of  these  vegetable  membranes,  having  been 
filled  with  a  solution  of  oxalic  acid,  and  then 
plunged  into  rain-water,  the  included  fluid  rose 


ENDOSMOSIS. 


109 


gradually  in  the  tube  of  the  endosmometer,  so 
that  the  endosmosis  was  from  the  water  towards 
the  acid,  the  reverse  of  that  which  takes  place 
when  the  endosmometer  is  furnished  with  an 
animal  membrane.  The  tartaric  and  citric 
acids  of  densities  below  1.05,  and  at  a  tempe- 
rature of  +  25°  cent,  exhibit  endosmosis  to- 
wards the  water  with  an  animal  membrane ; 
but  with  a  vegetable  membrane  the  case  is 
altered ;  the  endosmosis  being  then  directed 
from  the  water  towards  the  acid.  I  have  tried 
solutions  of  tartaric  acid,  decreasing  gradually 
in  density  from  1.05  (11  tartaric  acid  to  100 
solution)  to  a  density  so  low  as  1.0004,  (1  tar- 
taric acid,  1000  solution,)  and  always  seen  the 
endosmosis  towards  the  acid.  A  gradual  fall 
in  the  temperature  from  -J-  25°  to  near  zero  did 
not  affect  the  result. 

Sulphuric  acid  of  1.0274  density  and  at  a 
temperature  of  ■+■  4°  centes.  when  separated 
from  water  by  a  vegetable  membrane,  exhibited 
endosmosis  towards  the  acid  ;  separated  by  an 
animal  membrane,  however,  the  endosmosis 
was  towards  the  water. 

Hydrosulphuric  acid  (density  1.00628)  sepa- 
rated from  water  by  an  animal  membrane, 
always  shows  endosmosis  towards  the  water ; 
but  separated  by  a  vegetable  membrane,  the 
current  is  as  uniformly  towards  the  acid.  The 
experiment  from  which  I  deduce  this  result 
was  only  performed  at  a  temperature  of  -j-  5°. 

Sulphurous  acid  (density  1.02)  separated 
from  water  by  an  animal  membrane,  exhibits 
an  active  endosmosis  towards  the  water,  at 
every  temperature  from  zero  up  to  +  25°  centes. 
(I  have  made  no  experiments  on  endosmosis  at 
higher  temperatures.)  When  sulphurous  acid, 
of  the  density  of  1.02,  is  separated  from  water 
by  a  layer  of  vegetable  membrane,  it  presents 
neither  endosmosis  towards  the  acid  nor  endos- 
mosis towards  the  water ;  it  then  appears  to  be 
under  the  influence  of  the  simple  laws  presiding 
over  the  flow  of  fluids  by  filtration  :  there  is 
abolition  of  endosmosis.  [  was  anxious  to  see 
what  endosmotic  effects  it  would  produce  with 
an  endosmometer  closed  with  a  layer  of  baked 
clay,  and  it  was  not  without  surprise  that  I  saw 
the  current  flowing  vigorously  towards  the 
water.  I  had  put  the  acid  into  the  reservoir  of 
the  endosmometer;  and  the  included  fluid  rose 
to  a  considerable  height  in  the  tube  of  the  in- 
strument, which  I  had  taken  care  to  immerse 
in  water  to  the  place  where  the  acid  rose  in  the 
tube.  The  acid  continued  to  sink  in  the  tube 
of  the  endosmometer  for  four  hours,  and  had 
then  fallen  to  about  12  centimetres  below  the 
level  of  the  external  water ;  it  subsequently  be- 
gan to  rise  slowly  in  the  tube,  and  finally 
gained  the  level  of  the  external  water,  where  it 
remained.  It  was  obvious  that  the  sulphurous 
acid  had  sunk  in  the  tube  below  the  level  of  the 
water,  in  consequence  of  endosmosis  towards  the 
water,  and  that  its  subsequent  rise  to  the  level 
of  the  water  was  due  to  simple  filtration  through 
the  membrane.  Endosmosis  had  then  ceased. 
Sulphuric  acid,  diluted  with  water  to  the  den- 
sity of  1.0549,  exhibits  the  same  phenomena  as 
sulphurous  acid  when  separated  from  water  by 
a  lamina  of  baked  clay  :  it  first  occasions  en- 


dosmosis towards  the  water,  but  after  some 
minutes  this  endosmosis  ceases,  and  is  not  re- 
placed by  endosmosis  of  an  opposite  nature ; 
simple  filtration  from  the  effect  of  gravity  is  all 
that  then  takes  place;  endosmosis  of  each  kind 
is  put  a  stop  to.  Hydrosulphuric  acid,  sepa- 
rated from  water  by  a  lamina  of  baked  clay, 
gives  the  same  results  precisely  as  the  sulphu- 
ric acid.  This  phenomenon  is  rendered  still 
more  strange  by  the  fact  of  its  not  being  general. 
Thus  the  oxalic  acid  exhibits  endosmosis  to- 
wards the  acid  when  this  is  separated  from 
water  by  a  lamina  of  baked  clay.  This  fact  I 
ascertained  under  a  variety  of  temperatures 
from  +  4°  to  +  25°  centes.  and  with  solutions 
of  the  acid  of  as  great  density  as  could  be  ob- 
tained at  each  temperature,  as  well  as  with  so- 
lutions of  very  low  density.  The  tartaric  acid 
also  presents  endosmosis  towards  the  acid  when 
separated  from  water  by  a  lamina  of  baked 
clay.  I  had  formerly  found  *  that  a  little  sul- 
phuric or  hydrosulphuric  acid  added  to  gum- 
water,  causes  the  current  of  endosmosis  to  cease 
flowing  from  the  water  towards  the  gum-water, 
so  that  the  latter  fluid,  instead  of  rising  in  the 
tube  of  the  endosmometer,  begins  gradually  to 
fall.  I  then  attributed  this  phenomenon  to  the 
abolition  of  endosmosis  ;  but  it  is  evident  that 
in  certain  cases  it  is  owing  to  the  current  of  en- 
dosmosis changing  its  direction  and  flowing 
from  the  acid  towards  the  water.  Thus,  with 
reference  to  the  acidulated  gum-water,  of  which 
I  have  just  spoken,  when  placed  above  water, 
from  which  it  was  separated  by  an  animal 
membrane,  it  fell  in  the  stem  of  the  endosmo- 
meter and  flowed  towards  the  water,  either  from 
the  abolition  of  endosmosis,  and  in  virtue  of  its 
gravity,  or  in  consequence  of  the  establishment 
of  an  endosmotic  current  towards  the  external 
water.  Experiment  can  alone  determine  which 
of  these  two  causes  is  the  efficient  one  of  the 
descent  of  the  acidulated  fluid  in  the  stem  of 
the  endosmometer.  The  whole  of  the  acids 
used  of  such  density  as  comports  with  the  pro- 
duction of  endosmosis  towards  water,  and  in 
sufficient  quantity,  are  adequate  to  overcome 
the  disposition  which  any  fluid  may  possess  to 
produce  endosmosis  in  the  opposite  direction. 
Here  is  a  case  in  illustration  of  this  point.  The 
power  of  sugar-water  in  causing  endosmosis  is 
very  great,  as  I  have  shown  already.  Water 
holding  no  more  than  one-sixteenth  of  its 
weight  of  sugar  in  solution  causes  rapid  endos- 
mosis from  the  water  towards  the  solution.  But 
I  have  found  that,  by  adding  to  this  sweet 
liquid  a  quantity  of  oxalic  acid  equal  in  weight 
to  that  of  the  sugar  which  it  holds  in  solution, 
the  direction  of  the  endosmotic  current  is  im- 
mediately changed  ;  the  flow  is  no  longer  from 
the  water  towards  the  solution,  but  from  the 
sweet-sour  solution  towards  the  water,  so  that 
the  oxalic  acid  may  be  said  to  compel  the  sac- 
charine solution  to  which  it  is  added  to  take 
the  direction  of  the  endosmotic  current  which 
is  proper  to  it.  Here  it  is  the  viscid  and  dense 
fluid,  with  little  power  of  capillary  ascent, 
which  traverses  the  animal  membrane  with 

*  Nouv.  Rech.  sur  l'Endosmose,  p.  8. 


110 


ENDOSMOSIS. 


greater  ease  and  more  rapidity  than  pure  water. 
This  may  be  added  to  the  facts  set  forth  already 
to  prove,  in  the  most  decided  manner,  that  the 
greater  power  of  permeation  manifested  by  one 
of  the  two  fluids  in  experiments  on  endosmosis 
does  not  follow  from  any  greater  viscidity  it 
may  possess  than  the  fluid  opposed  to  it.  In 
sixteen  parts  of  water  I  dissolved  two  parts  of 
sugar  and  one  part  of  oxalic  acid.  In  this  so- 
lution I  plunged  the  reservoir  of  an  endosmo- 
meter,  closed  with  a  piece  of  bladder,  and  filled 
with  pure  water  :  this  did  not  show  any  diffe- 
rence of  level  in  the  tube  during  the  two  hours 
that  I  continued  the  experiment.  There  was 
consequently  no  endosmosis.  Nevertheless,  I 
found  that  the  water  contained  in  the  endosmo- 
meter  contained  a  large  quantity  of  oxalic  acid, 
whether  tested  by  the  addition  of  lime-water 
or  by  the  palate,  which  last  also  detected  the 
presence  of  sugar.  Thus  the  sweet-sour  fluid, 
exterior  to  the  endosmometer,  had  penetrated 
the  water  contained  within  its  cavity.  If  this 
circumstance  was  proclaimed  by  no  increase  in 
the  volume  of  the  water,  this  undoubtedly  was 
owing  to  the  included  water  having  lost  by  the 
descending  counter-current  an  amount  exactly 
equal  to  the  amount  it  had  gained  by  the  in- 
ward or  ascending  current.  There  was  no  en- 
dosmosis in  the  sense  in  which  I  use  that  word, 
although  it  is  certain  that  there  were  two  active 
antagonist  currents  athwart  the  membrane  which 
separated  the  two  fluids.  It  must  not  be  lost 
sight  of  that  I  only  give  the  title  of  endosmosis 
to  a  stronger  current  opposed  to  a  weaker 
counter-current,  antagonists  to  each  other,  and 
proceeding  simultaneously  athwart  the  septum, 
dividing  the  two  fluids  which  are  made  the 
subjects  of  experiment.  The  instant  these  two 
antagonist  currents  become  equal,  there  is  no 
accumulation  of  fluid  on  one  side,  and  there  is 
then  no  longer  any  effort  at  dilatation  or  im- 
pulsion ;  in  a  word,  there  is  no  longer  any 
endosmosis. 

The  opposite  directions  in  which  the  endos- 
mosis towards  water,  effected  by  acids  of  deter- 
minate density,  and  the  endosmosis  from  water 
occasioned  by  other  fluids,  would  lead  us  to 
conclude  that  in  placing  such  a  fluid  as  gum- 
water  or  sugar-water  in  an  endosmometer  fur- 
nished with  an  animal  membrane,  and  in  con- 
tact externally  with  an  acid  solution  of  appro- 
priate density,  we  should  have  a  much  more 
rapid  endosmosis  towards  the  included  fluid 
than  if  it  were  pure  water  in  which  the  endos- 
mometer was  plunged  ;  and  this  in  fact  is  what 
I  have  found  to  be  the  case  by  experiment. 
Into  an  endosmometer,  closed  with  a  piece  of 
bladder,  I  poured  a  solution  of  five  parts  of 
sugar  in  twenty-four  parts  of  water.  .Having 
plunged  the  reservoir  of  the  instrument  into 
water,  I  obtained  in  the  course  of  an  hour  an 
ascent  of  the  included  fluid,  which  may  be  re- 
presented by  the  number  9.  The  reservoir  of 
the  same  endosmometer  filled  with  a  portion  of 
the  same  saccharine  solution,  having  been 
plunged  into  a  solution  of  oxalic  acid,  the  den- 
sity of  which  was  1.014,  (3.2  parts  acid  to  100 
solution,)  I  obtained  in  the  course  of  an  hour 
an  ascent  of  the  included  fluid,  which  required 


to  be  represented  by  the  number  27.  The 
substitution  of  a  solution  of  oxalic  acid  for 
pure  water  consequently  caused  the  amount  of 
endosmosis  in  the  same  interval  of  time  to  be 
tripled.  I  obtained  like  results  with  the  tarta- 
ric and  citric  acids,  employed  of  the  densities 
required  to  enable  them  to  produce  endosmosis 
towards  water.  From  these  experiments  it 
would  appear  that  water,  charged  with  a  small 
proportion  of  one  of  the  acids,  of  which  men- 
tion has  been  made,  possesses  a  power  of  pene- 
tration athwart  animal  membranes  greater  than 
that  inherent  in  pure  water.  But  a  direct  ex- 
periment, detailed  in  an  earlier  part  of  this 
paper,  proves  that  this  is  not  the  case ;  pure 
water  used  by  itself  is  still  the  fluid  that  pos- 
sesses the  greatest  power  of  penetrating  through 
animal  membranes.  If,  consequently,  in  those 
experiments  which  I  have  last  described,  the 
water  charged  with  acid  passed  more  readily 
and  more  copiously  into  the  saccharine  solu- 
tion than  pure  water,  this  happens  undoubtedly 
from  other  causes  or  conditions  which  I  cannot 
take  upon  me  to  explain,  but  which  appear  to 
be :  1st.  A  reciprocal  action  between  the  two 
heterogeneous  fluids,  an  action  which  modifies, 
which  even  completely  inverts  the  natural 
power  of  penetration  possessed  by  each  of  the 
fluids  when  employed  singly  ;  2d.  %  particular 
action  of  the  membrane  upon  the  two  fluids 
which  penetrate  it,  an  action  which,  with  the 
animal  membrane,  gives  the  stronger  current 
or  current  of  endosmosis  to  the  acid  solution  of 
due  density,  and  the  weaker  current  or  coun- 
ter-current of  exosmosis  to  the  pure  water.  It 
seems  to  me  impossible  to  deny  this  peculiar 
action  to  the  animal  membrane,  when  we  see 
that  a  vegetable  membrane  in  the  same  circum- 
stances produces  endosmotic  phenomena  di- 
rectly the  reverse.  The  peculiar  influence  of 
the  membranous  septum  is  likewise  manifested 
in  a  very  striking  way  in  the  experiment  in 
which  I  have  shown  that  the  current  of  endos- 
mosis flows  from  water  towards  alcohol  when 
these  two  fluids  are  divided  by  an  animal 
membrane,  and,  on  the  contrary,  that  the  cur- 
rent of  endosmosis  flows  from  alcohol  towards 
water  when  the  two  fluids  are  separated  by  a 
membranous  septum  of  caoutchouc. 

Endosmosis,  in  the  present  order  of  things, 
is  a  phenomenon  restricted  to  the  realm  of  or- 
ganization ;  it  is  nowhere  observed  in  the  inor- 
ganic world.  It  is  in  fact  only  among  organ- 
ized beings  that  we  observe  fluids  of  different 
density  separated  by  thin  septa  and  capillary 
pores ;  we  meet  with  nothing  of  the  same  kind 
among  inorganic  bodies.  Endosmosis,  then, 
is  a  physical  phenomenon  inherent  exclusively 
in  organic  bodies,  and  observation  teaches  us 
that  this  phenomenon  plays  a  part  of  the  high- 
est importance  in  their  economy.  It  is  among 
vegetables  especially  that  the  importance  of  the 
phenomenon  strikes  us ;  I  have,  in  fact,  de- 
monstrated that  it  is  to  endosmosis  that  are 
due,  in  great  part,  the  motions  of  the  sap,  and 
particularly  its  very  energetic  ascending  motion. 
I  have  also  shown  that  all  the  spontaneous  mo- 
tions of  vegetables  are  referable  to  endosmosis. 
The  organic  vegetable  tissue  is  composed  of  a 


ENTOZOA. 


Ill 


multitude  of  agglomerated  cells  mingled  with 
tubes.  The  whole  of  these  hollow  organs,  the 
parietes  of  which  are  extremely  thin,  and  which 
contain  fluids  the  densities  of  which  vary,  ne- 
cessarily make  mutual  exchanges  of  their  con- 
tents by  way  of  endosmosis  and  exosmosis. 
Nor  can  we  suppose  but  that  the  same  pheno- 
mena take  place  among  the  various  cells  and 
cavities  exhibited  by  the  organism  of  animals. 
But  the  effects  of  endosmosis,  its  influence  on 
the  physiological  phenomena  presented  by  ani- 
mals, has  yet  to  be  determined  ;  and  here,  un- 
doubtedly, the  physiologist  has  an  ample  field 
before  him  for  inquiry.  I  shall  only  say  in 
conclusion,  and  with  reference  to  this  very  in- 
teresting part  of  the  subject,  that  I  have  satis- 
fied myself  that  it  is  to  endosmosis  that  the 
motions  of  the  well-known  spiral  spring  tubes  of 
the  milt  of  the  cuttle-fish,  when  put  into  water, 
are  owing. 

(H.  Dutrochet.) 

ENTOZOA,  (euto?,  intus,  tpov,  animal,) 
eA/aikGe;  crrgoyyvhoi,  eA^ivQe;  wXcnuca,  ctcry.a.- 
£»Je;,  Arist.  et  Antiq.  Vers  Intestinaux,  Cuv. 
Entelmintha,  Splanchnelmintha,  Zeder. 

The  term  Entozoa,  like  the  term  Infusoria, 
is  indicative  of  a  series  of  animals,  associated 
together  chiefly  in  consequence  of  a  similarity 
of  local  habitation  ;  which  in  the  present  class 
is  the  internal  parts  of  animals. 

In  treating  therefore  of  the  organization  of 
these  parasites,  we  are  compelled  to  consider 
them,  not  as  a  class  of  animals  established 
on  any  common,  exclusive,  or  intelligible  cha- 
racters, but  as  the  inhabitants  of  a  peculiar  dis- 
trict or  country. 

They  do  not,  indeed,  present  the  types  of  so 
many  distinct  groups  as  those  into  which  the 
naturalist  finds  it  necessary  to  distribute  the 
subjects  of  a  local  Fauna,  yet  they  can  as  little 
be  regarded  as  constituting  one  natural  assem- 
blage in  the  system  of  Animated  Nature. 
And  it  may  be  further  observed  that  as  the 
members  of  no  single  class  of  animals  are  con- 
fined to  one  particular  country,  so  neither  are 
the  differgfit  natural  groups  of  Entozoa  exclu- 
sivelv^jepresented  by  species  parasitic  in  the 
interior  of  animal  bodies.  Few  zoologists,  we 
apprehend,  would  dissociate  and  place  in  sepa- 
rate classes,  in  any  system  professing  to  set 
forth  the  natural  affinities  of  the  animal  king- 
dom, the  P lunar ia  from  the  Tremutoda,  or  the 
Vibrioniclce  from  the  microscopic  parasite  of  the 
human  muscles. 

In  the  present  article  it  is  proposed  to  divide 
the  various  animals  confounded  together  under 
the  common  term  of  Entozoa  or  Entelmintha 
into  three  primary  groups  or  classes;  and,  as  in 
speaking  of  the  traits  of  organization  common 
to  each,  it  becomes  not  only  convenient  but 
necessary  to  have  terms  for  the  groups  so 
spoken  of,  they  will  be  denominated  Protel- 
mint/ia,  Sterelmintha,  and  Ccelelmintha  respec- 
tively. 

It  may  be  observed  that  each  of  these 
groups,  which  here  follow  one  another  in  the 
order  of  their  respective  superiority  or  com- 
plexity of  organization,  has  been  indicated, 


and  more  or  less  accurately  defined  by  pre- 
vious zoologists.  After  the  dismemberment 
of  the  Infusoria  of  Cuvier  into  the  classes 
Polygastrica  and  Kotifera,  which  resulted 
from  the  researches  of  Professor  Ehrenberg 
into  the  structure  of  these  microscopic  beings, 
there  remained  certain  families  of  Animalcules 
which  could  not  be  definitely  classed  with 
either :  these  were  the  Cercariadce  and  Vibrio- 
nida.  Mr.  Pritchard,  in  his  very  useful  work 
on  Animalcules,  has  applied  to  the  latter  fa- 
mily the  term  Entozoa,  from  the  analogy  of 
their  external  form  to  the  ordinary  species  of 
intestinal  worms  ;  and  it  is  somewhat  singular 
that  a  species  referrible  to  the  Vibrionidce 
should  subsequently  have  been  detected  in  the 
human  body  itself.  Premising  that  the  tribe 
Vibrionidie  as  at  present  constituted  is  by  no 
means  a  natural  group,  and  that  some  of  the 
higher  organized  genera,  as  Anguillula,  are  re- 
ferrible to  the  highest  rather  than  the  lowest  of 
the  classes  of  Entozoa,  we  join  the  lower  organ- 
ized genera,  which  have  no  distinct  oviducts,  and 
which,  like  the  parasitic  Trichina,  resemble  the 
foetal  stage  of  the  Nematoid  worms,  with  the 
Cercariada,  in  which  the  generative  apparatus 
is  equally  inconspicuous;  and  these  families, 
dismembered  from  the  Infusoria  of  Lamarck, 
constitute  the  class  Protelmintha,  the  first 
or  earliest  forms  of  Entozoa. 

The  second  and  third  classes  correspond  to 
the  two  divisions  of  the  class  Intestinalia,  in 
the  '  Regne  Animal '  of  Cuvier,  and  which  are 
there  respectively  denominated  '  Vers  Intesti- 
naux Parenchymateux,'  and  '  Vers  Intestinaux 
Cavitaires.'  The  characters  of  these  classes  will 
be  fully  considered  hereafter;  and  in  the  mean- 
while but  little  apology  seems  necessary  for  in- 
venting names  expressive  of  the  leading  distinc- 
tion of  each  group  as  Latin  equivalents  for  the 
compound  French  phrases  by  which  they  have 
hitherto  been  designated.  Etyu><?  appears  to 
have  been  applied  by  the  Greeks  to  the  in- 
testinal worms  generally,  as  Aristotle  speaks 
of  eA^ivGe?  TrXaTEtai,  intestinalia  lata,  and 
sA^Se?  argoyyvhcct,  intestinalia  teretia.  In 
framing  the  terms  Sterelmintha  and  Calelmin- 
tha,  from  Efyui*;  o-reqta.,  a  solid  or  parenchy- 
matous worm,  and  Etyuv;  x.oi\ri,  a  hollow  or 
cavitary  worm,  I  follow  the  example  of  Zeder, 
and  omit  the  aspirate  letter.  It  may  be  ob- 
served by  the  way  that  Zeder's  term  Splanchnel- 
mintha, besides  including  animals  which  are 
developed  in  other  parts  than  the  viscera,  is, 
like  the  term  Entozoa,  open  to  the  objection  of 
being  applied  to  a  series  of  animals  which,  ac- 
cording to  their  organization,  belong  to  distinct 
classes. 

The  limits  and  object  of  the  present  article 
obviously  forbid  an  extensive  or  very  minute 
consideration  of  the  anatomical  details  of  each 
of  these  classes  of  animals,  and  we  are  com- 
pelled to  confine  ourselves  almost  exclusively 
to  such  illustrations  of  their  respective  plans 
of  organization  as  are  afforded  by  the  species 
referrible  to  each  which  inhabit  the  human  body. 

If  a  drop  of  the  secretion  of  the  testicle  be 
expressed  from  the  divided  vas  deferens  in 
a  recently  killed  mammiferous  animal,  which 


112 


ENTOZOA. 


has  arrived  at  maturity,  and  be  diluted  with 
a  little  pure  tepid  water  and  placed  in  the 
field  of  a  microscope,  a  swarm  of  minute 
beings  resembling  tadpoles  will  be  observed 
moving  about  with  various  degrees  of  velo- 
city, and  in  various  directions,  apparently  by 
means  of  the  inflexions  of  a  filamentary  caudal 
appendage.  These  are  the  seminal  animalcules, 
Zoosperms,  or  Spermatozoa  (Jig-  51):  and,  as 
it  is  still  undetermined  whether  they  are  to  be 
regarded  as  analogous  to  the  moving  filaments 
of  the  pollen  of  plants,  or  as  independent  or- 
ganisms, it  has  been  deemed  more  convenient 
to  consider  them  zoographically  in  the  present 
article  as  members  of  the  class  Entozoa. 

The  body  to  which  the  tail  is  attached  is 
of  an  oval  and  flattened  or  compressed  form, 
so  that,  when  viewed  sideways,  the  Zoosperm 
appears  to  be  a  moving  filament  like  a  minute 
Vibrio.  It  is  this  compressed  form  of  the 
body  which  principally  distinguishes  the  Sper- 
matozoa or  seminal  Cercaria,  from  the  true 
Cercaria  of  vegetable  infusions,  in  which  the 
body  is  ovoid  or  cylindrical ;  the  caudal  ap- 
pendage of  the  Spermatozoa  is  also  propor- 
tionally longer  than  in  the  Cercaria. 

In  some  species  of  the  latter  genus  an  oral 
aperture  and  ocelliform  specks  of  an  opake 
red  colour  have  been  obsprved  on  the  anterior 
part  of  the  body,  and  they  manifest  their  sen- 
sibility to  light  by  collecting  towards  the  side 
of  the  vessel  exposed  to  that  influence.  In 
the  Zoosperms,  which  are  developed  exclu- 
sively in  the  dark  recesses  of  animal  bodies, 
the  simplest  rudiments  of  a  visual  organ  would 
be  superfluous ;  they  are,  in  fact,  devoid  of 
ocelli,  and  even  an  oral  aperture  has  not  yet 
been  detected  in  these  simplest  and  most  mi- 
nute of  Entozoa.  In  neither  the  Zoosperms 
nor  the  Cercaria  has  the  polygastric  struc- 
ture been  determined.  On  the  contrary,  some 
of  the  non-parasitic  species,  as  the  Cercaria 
Lemna,  are  stated  to  have  '  a  true  alimen- 
tary canal,  not  polygastric'  * 

The  Spermatozoa  are  not,  however,  the  only 
examples  of  the  present  order  of  Protelmintha 
which  have'  their  habitat  in  the  interior  of  living 
animals ;  many  of  the  Entozoa  themselves  have 
been  observed  to  be  infested  by  internal  para- 
sites, which  are  referrible  by  their  external  form 
to  the  Cercariada. 

Although  no  distinct  organs  of  generation 
have  been  detected,  there  is  reason  to  suspect 
that  the  Spermatozoa  are  oviparous :  they  are 
also  stated  to  propagate  by  spontaneous  fission ; 
the  separation  taking  place  between  the  disc  of 
the  body  and  the  caudal  appendage;  each  of 
which  develope  the  part  required  to  form  a 
perfect  whole. 

The  Zoosperms  of  each  genus  of  animals 
present  differences  of  form  or  proportion,  and 
frequently  also  differences  of  relative  size  as 
compared  to  the  animal  in  which  they  are  deve- 
loped ;  thus,  in  the  figures'  subjoined,  which 
are  all  magnified  in  the  same  degree,  the 
Zoosperm  from  the  Rabbit  is  nearly  as  large  as 
that  from  the  Bull,  (fig.  51.) 

*  Pi'itchard's  Animalcules,  p.  184. 


Bull. 


Rabbit. 


Sparrow. 


Silk-worm  Moth. 
Fig.  52. 


1 

Development  of  Sper- 
matozoa, Hunting. 


They  appear  to  be 
formed  in  the  seminal 
secretion  under  similar 
laws  to  those  which  pre- 
side over  the  develop- 
ment of  other  Entozoa 
in  the  mucous  secretion 
of  the  Intestines,  &c.,but 
are  more  constant  in  their 
existence,  and  must  there- 
fore be  regarded  as  fulfil- 
ling some  more  important 
office  in  the  economy  of 
the  animal  in  which  they 
exist. 

They  are  not  found  in 
the  seminal  passages  or 
glands  until  the  full  pe- 
riod of  puberty;  and  in 
some  cases  would  seem 
to  be  periodically  deve- 
loped. In  the  Hedgehog 
and  Mole,  which  exhibit 
a  periodical  variation  in 
the  size  of  the  testes  in  a 
well-marked  degree,  the 
Spermatozoa  are  not  ob- 
servable in  those  glands 
during    their    state  of 
quiescence   and  partial 
atrophy.  Professor  Wag- 
ner* examined  the  testes 
of   different  Passerine 
Birds  in  the  winter  sea- 
son, when  those  bodies 
are  much  diminished  in 
size.    (See  vol.i.  p.  354, 
fig.  183.)  They  then  con- 
tained only  granular  sub- 
stances, without  a  trace  of 
the  Spermatozoa.  When 
the  same  bodies  were  ex- 
amined in  spring,  they 
were  found  to  contain 
spherical  granules  of  dif- 
ferent sizes  and  appear- 
ances, (A,  B,  fig.  52,) 
which  led  to  the  suppo- 
sition that  they  were  the 
ova  of  the  Spermatozoa  in 
different  stages  of  deve- 
lopment, and  capsules 
containing  each  a  nume- 
rous group  of  Sperma- 
tozoa (C)  were  also  pre- 
sent ;  whence  it  would 
appear  that  many  of  these 
animalcules  were  deve- 
loped from  a  single  ovum. 
In  the  semen  contained 
in  the  vasa  deferentia  the 
Spermatozoa  (D)  were  in 
great  numbers,  having 
escaped  from  their  cap- 
sules ;  they  exhibit  a  re- 
markable rotation  on  their 

*  Mailer's  Archiv.  1836, 
p.  225. 


ENTOZOA. 


113 


axis,  which  continues  for  five  or  ten  minutes  after 
the  death  of  the  bird  in  which  they  are  developed. 
Some  have  supposed  that  these  animalcules 
were  the  result  of  a  putrefactive  process,  but 
this  is  disproved  by  their  presence  in  testicles 
which  have  been  removed  from  living  animals, 
and  by  their  ceasing  in  fact  to  exist  when  the 
seminal  secretion  begins  to  undergo  a  decom- 
position. Their  extraordinary  number  is  such 
that  a  drop  of  semen  appears  as  a  moving  mass, 
in  which  nothing  can  be  distinguished  until  it 
has  been  diluted  as  before-mentioned,  when 
the  animalcules  are  seen  to  disengage  them- 
selves and  commence  their  undulatory  move- 
ments. By  means  of  the  continual  agitation 
thus  produced  the  chemical  elements  of  the 
fecundating  fluid  are  probably  kept  in  a  due 
state  of  admixture.  By  the  same  movements 
the  impregnating  influence  of  the  semen  may 
be  carried  beyond  the  boundary  which  it 
reaches  in  the  female  organs  from  the  expulsive 
actions  of  the  coitus.  It  has  been  conjectured 
that  from  the  rapid  and  extensive  multiplication 
of  these  animalcules  they  may  contribute  to  pro- 
duce the  stimulus  of  the  rut.  But  the  con- 
sideration of  the  part  which  the  Zoosperms 
may  play  in  generation  belongs  to  the  Physio- 
logical history  of  that  function,  and  would 
lead  to  discussions  foreign  to  the  present 
article,  which  treats  of  their  form  and  structure 
simply  as  the  parasites  of  animal  bodies. 

In  the  human  subject  the  form  of  the  Zoo- 
sperm  is  accurately  represented  in  Jig.  51. 

Among  the  cold-blooded  Reptiles  the  Zoo- 
sperms  of  the  Frog  (jig.  51)  have  been  ex- 
amined with  most  attention,  and  have  been 
the  subject  of  interesting  experiments  in  the 
hands  of  Spallanzani  and  Dumas. 

The  milt  or  developed  testicle  of  the  osseous 
Fishes  abounds  with  moving  bodies  of  a  glo- 
bular form.  In  the  Shark  and  Ray  the  Zoo- 
sperms  are  of  a  linear  and  spiral  form. 

The  molluscous  animals  are  favourable  sub- 
jects for  the  examination  of  the  present  tribe 
of  Entozoa  on  account  of  the  great  relative 
size  of  the  parasites  of  the  seminal  secretion. 
They  are  mostly  of  a  filamentary  form,  and 
have  long  been  known  in  the  Cephalopods. 
The  Zoosperms  of  the  Snail  (  Helix  Pomatia) 
present  an  undulated  capillary  body,  and  move 
sufficiently  slowly  to  permit  their  being  readily 
followed  by  the  eye. 

The  Spermatozoa  have  been  detected  and 
described  in  the  different  classes  of  the  Arti- 
culate Animals.  In  Insects  they  are  of  a  fine 
capillary  form,  and  are  generally  aggregated  in 
bundles.  They  abound  in  the  semen  of  the 
Anellides  and  Cirripeds;  lastly,  these  parasites 
have  been  found  to  exist  in  vast  numbers  in  the 
spermatic  tubes  of  the  higher  organized  En- 
tozoa themselves. 

The  second  tribe  of  Protelmint/ia  includes 
those  cylindrical,  filiform,  eel-like,  microscopic 
Animalcules  which  abound  in  decayed  vege- 
table paste,  stale  vinegar,  &c.  together  with 
others  which  have  attracted  particular  attention 
by  the  destructive  waste  caused  by  certain  spe- 
cies which  are  parasitic  on  living  vegetables. 
These  animalcules  are  termed  Vibrionidce  from 

vol.  ir. 


their  darting  or  quivering  motion.  They  differ 
from  the  polygastric  Infusories,  not  only  in 
the  absence  of  internal  stomachs  but  also  of 
external  cilia,  which  is  inferred  by  their  not 
exciting  any  currents  when  placed  in  coloured 
water.  They  present  a  higher  grade  of  organi- 
zation than  the  Cercarian  tribe  in  the  presence 
of  a  straight  alimentary  canal,  which  is  re- 
markably distinct  in  some  of  the  higher  forms 
of  the  group,  as  the  Gordioides  and  Oxyu- 
roides  of  Bory  St.  Vincent. 

The  higher  organized  Vibriones  have  distinct 
generative  organs,  and  are  ovo-viviparous. 

In  the  species  of  Vibrio  which  infests  the 
grains  of  wheat  and  occasions  the  destructive 
disease  called  Ear-cockle  or  Purples,  Mr.  Bauer 
found  the  ova  arranged  between  the  alimentary 
canal  and  the  integument,  in  a  chaplet  or 
moniliform  oviduct  which  terminated  by  a 
bilabiate  orifice  at  a  little  distance  from  the 
caudal  extremity  of  the  body.  The  ova  are 
discharged  at  this  orifice  in  strings  of  five  or 
six,  adhering  to  each  other.  Each  egg  is  about 
3^jth  of  an  inch  long,  and  g'^th  or  ^th  in  di- 
ameter :  and  they  are  sufficiently  transparent 
to  allow  of  the  young  worm  being  seen  within : 
and  the  embryo,  in  about  an  hour  and  a  half 
after  the  egg  is  laid,  extricates  itself  from  the 
egg-coverings.  Of  the  numerous  individuals 
examined  by  Mr.  Bauer,  not  any  exhibited 
external  distinctions  of  sex,  and  he  believes 
them  to  be  hermaphrodites. 

In  the  Anguillula  aceti,  or  common  Vinegar- 
eel,  Bory  St.  Vincent  has  distinguished  indi- 
viduals in  which  a  slender  spiculum  is  pro- 
truded from  the  labiate  orifice  corresponding 
to  that  above  described  from  which  the  ova 
are  extruded ;  these  individuals  he  considers 
to  be  males ;  they  are  much  less  numerous 
than  the  females ;  are  considerably  smaller ; 
and  the  internal  chaplet  of  ova  is  not  dis- 
cernible in  them.  In  the  female  the  ova  are 
arranged  in  two  series  on  each  side  of  the 
alimentary  canal,  and  the  embryo  worms  are 
usually  seen  to  escape  from  the  egg-coverings 
while  yet  within  the  body  of  the  parent,  and 
to  be  born  alive.  Ehrenberg  figures  the  two 
sexes  of  Anguillula fluviatilis  'm  his  first  trea- 
tise on  the  Infusoria  (tab.  vii.  fig.  5.*)  The 
granular  testis  and  intromittent  spiculum,  which 
is  single,  are  conspicuous  in  the  male ;  the  ova 
in  the  female  are  large  and  arranged  as  in 
Anguillula  aceti.  Such  an  organization,  it  is 
obvious,  closely  approximates  these  higher 
Vibrionidae  to  the  nematoid  Entozoa,  as  the 
Ascarides  and  Oxyuri,  and  further  researches 
on  this  interesting  group  will  doubtless  lead  to 
the  dismemberment  of  the  Oxyuroid  family 
from  the  more  simple  Vibrionidce,  as  the 
genera  Bacterium,  Spirillum,  and  Vibrio,  with 
which  they  are  at  present  associated. 

To  the  group  composed  of  the  three  last- 
named  genera,  the  microscopic  parasite  of  the 
human  muscles,  termed  Trichina  Spiralis,  is 
referrible.f 

*  Organisation,  systematik  und  georaphisches 
Verhaltniss  der  Infusionthieschen,  1«30. 

t  Zool.  Trans,  vol.  i.  p.  315,  and  Zool.  Pro- 
ceedings,  for  February,  1835. 

I 


114 


ENTOZOA. 


This  singular  Entozoon  I  discovered  in  a 
portion  of  the  muscles  of  a  male  subject,  which 
■was  transmitted  to  me  for  examination,  at  the 
beginning  of  1835,  by  Mr.  Wormald,  Demon- 
strator of  Anatomy  at  St.  Bartholomew's  Hos- 
pital, on  account  of  a  peculiar  speckled  ap- 
pearance of  those  parts.  This  state  of  the 
muscles  had  been  noticed  by  that  gentleman 
as  an  occasional  but  rare  occurrence  in  subjects 
dissected  at  St.  Bartholomew's  in  several  pre- 
vious years. 

The  portion  of  muscle  was  beset  with  minute 
whitish  specks,  as  represented  in  the  subjoined 
cut  (fig-  53) :   and  in  fourteen  subsequent 
instances  which  have 
Fig.  53.  come  to  my  knowledge 

of  the  presence  of  this 
entozoon  in  the  human 
subject,  the  muscles 
have  presented  very 
similar  appearances. 
The  specks  are  produ- 
ced by  the  cysts  con- 
taining the  worm,  and 
vary,  as  to  their  dis- 
tinctness, according  to 
their  degreesof  opacity, 
whiteness,  and  hard- 
ness. 

The  cysts  are  very 
readily  detected  by 
gently  compressing  a 
thin  slice  of  the  infect- 
ed muscle  between  two 
pieces  of  glass  and  ap- 
plying a  magnifying  power  of  an  inch  focus. 
They  are  of  an  elliptical  figure,  with  the  extremi- 
ties more  or  less  attenuated,  often  unequally 
elongated,  and  always  more  opaque  than  the  body 
or  intermediate  part  of  the  cyst,  which  is,  in 
general,  sufficiently  transparent  to  shew  that 
it  contains  a  minute  coiled-up  worm. 

The  cysts  are  always  arranged  with  their 
long  axis  parallel  to  the  course  of  the  mus- 
cular fibres,  which  probably  results  from  their 
yielding  to  the  pressure  of  the  contained  worm, 
and  becoming  elongated  at  the  two  points 
where  the  separation  of  the  muscular  fasciculi 
most  readily  takes  place,  and  offers  least  re- 
sistance ;  and  for  the  same  reason  one  or  both 
of  the  extremities  of  the  cyst 
become  from  repeated  pressure 
and  irritation  thicker  and  more 
opaque  than  the  rest.  That  the 
adhesive  process  in  the  cellular 
tissue,  to  which  I  refer  the  for- 
mation of  the  cyst,  was  most 
active  at  the  extremities  of  the 
cyst  is  also  evinced  by  the  closer 
adhesion  which  these  parts  have 
to  the  surrounding  cellular  tissue. 

The  cysts  measure  generally 
about  j'jth  of  an  inch  in  their 
longitudinal,  and  -^th  of  an  inch 
in  their  transverse  diameters : 
like  other  cysts  which  are  the 
result  of  the  adhesive  inflamma- 
tion, they  have  a  rough  exterior, 
and  are  of  a  laminated  texture. 


Cysts  of  the  Trichina 
Spiralis  in  situ,  natural 
size. 


A  separateCh/st 
of  the  Trichi- 
na, which  is 
seen  coiled  up 
through  the 
transparent 
coats,  magni- 
fied. 


Fig.  55. 


The  innermost  layer  (fig.  54),  however,  can 
sometimes  be  detached  entire,  like  a  distinct 
cyst,  from  the  outer  portion,  and  its  contour 
is  generally  well  marked  when  seen  by  trans- 
mitted light.  By  cutting  off  the  extremity  of  the 
cyst,  which  may  be  done  with  a  cataract  needle 
or  fine  knife,  and  gently  pressing  on  the  opposite 
extremity,  the  Trichina  and  the  granular  secre- 
tion with  which  it  is  surrounded,  will  escape  ; 
and  it  frequently  starts  out  as  soon  as  the  cyst 
is  opened.  But  this  delicate  operation  requires 
some  practice  and  familiarity  with  microsco- 
pical dissection,  and  many  attempts  may  fail 
before  the  dissector  succeeds  in  liberating  the 
worm  entire  and  uninjured. 

When  first  extracted,  the  Trichina  is  usually 
disposed  in  two  or  two  and  a  half  spiral  coils  : 
when  straightened  out  (which  is  to  be  done 
with  a  pair  of  hooked  needles,  when  the  sur- 
rounding moisture  is  so  far  evaporated  as  that 
the  adhesion  of  the  middle  of  the  worm  to  the 
glass  it  rests  upon  shall  afford  a  due  resistance 
to  a  pressure  of  the  needle  upon  the  extremi- 
ties), it  measures  ^th  of  an  inch  in  length  and 
.^gth  of  an  inch  in  diameter,  and  now  requires 
for  its  satisfactory  examination  a  magnifying 
power  of  at  least  200  linear  admeasurement. 
The  worm  (fig.  55)  is  cylindrical  and  fili- 
form, terminating  obtusely 
at  both  extremities,  which 
are  of  unequal  sizes ;  taper  - 
ing  towards  one  end  for 
about  one-fourth  part  of  its 
length,  but  continuing  of 
uniform  diameter  from  that 
point  to  the  opposite  ex- 
tremity. 

Until  lately  it  was  only 
at  the  larger  extremity  that 
I  have  been  able  to  distin- 
guish an  indication  of  an 
orifice,  and  this  is  situated 
in  many  specimens  in  the  centre  of  a  transverse, 
bilabiate,  linear  mouth,  (a,  fig.  54.) 

A  recently  extracted  living  worm,  when  ex- 
amined by  a  good  achromatic  instrument  be- 
fore any  evaporation  of  the  surrounding  fluid 
has  affected  the  integument,  presents  a  smooth 
transparent  exterior  skin,  inclosing  apparently 
a  fine  granular  parenchyma.  It  is  curious  to 
watch  the  variety  of  deceptive  appearances  of 
a  more  complex  organization  which  result  from 
the  wrinkling  of  the  delicate  integument.  I 
have  sometimes  perceived  what  seemed  to  be 
a  sacculated  or  spiral  intestine ;  and,  as  eva- 
poration proceeds,  this  has  apparently  been 
surrounded  by  minute  tortuous  tubes ;  but  the 
fallacy  of  the  latter  appearance  is  easily  de- 
tected. A  structure,  which  I  have  found  in 
more  recent  and  better  preserved  specimens 
than  those  which  were  the  subjects  of  my  first 
description,  is  evidently  real,  and  may  pro- 
bably belong  to  the  generative  system  of  the 
Trichina  ;  it  consists  of  a  small  rounded  cluster 
of  granules  of  a  darker  or  more  opaque  nature 
than  the  rest  of  the  body ;  it  is  situated  about 
one-fifth  of  the  length  of  the  animal  from  the 
larger  or  anterior  extremity,  and  extends  about 
half-way  across  the  body. 


Trichina  spiral) 
magnified. 


ENTOZOA. 


115 


Dr.  Arthur  Farre,  whose  powers  of  patient 
and  minute  observation  and  practised  skill 
with  the  microscope,  are  well  known  to  those 
who  have  the  pleasure  of  his  acquaintance, 
discovered, by  theexamination  of  recent  Trichinae 
under  favourable  circumstances,  that  they  pos- 
sess an  intestinal  canal  with  distinct  parietes. 
He  describes  it  as  commencing  at  the  large  end 
of  the  worm,  bounded  by  two  parallel  but 
slightly  irregular  lines  for  about  one-fifth  of 
the  length  of  the  body,  and  then  assuming  a 
sacculated  structure  which  "  becomes  gradually 
lost  towards  the  smaller  end  where  the  canal 
assumes  a  zig-zag  or  perhaps  spiral  course,  and 
at  length  terminates  at  the  small  end."* 

In  a  recent  examination  of  some  Trichina 
from  an  aged  male  subject  at  St.  Bartholomew's 
Hospital,  I  perceived  a  transverse  slit  close  to 
the  small  extremity  on  the  concave  side,  which 
I  regard  as  the  anus. 

The  muscles  which  are  affected  by  the  Tri- 
china are  those  of  the  voluntary  class ;  and  the 
superficial  ones  are  found  to  contain  them  in 
greater  numbers  than  those  which  are  deep- 
seated;  the  pectoralis  major,  latissimus  dorsi, 
and  other  large  flat  muscles  usually  present 
them  in  great  abundance.  They  have  been 
detected  in  the  muscles  of  the  eye,  and  even 
in  those  belonging  to  the  ossicles  of  the  ear, 
and  of  whose  actions  we  are  wholly  uncon- 
scious: they  also  occur  in  the  diaphragm,  in 
the  muscles  of  the  tongue,  in  those  of  the 
soft  palate,  in  the  constrictors  of  the  pharynx, 
in  the  levator  ani,  in  the  external  sphincter  ani, 
and  in  the  muscles  of  the  urethra.  But  they 
have  not  yet  been  detected  in  the  muscular 
tunic  of  the  stomach  and  intestines,  in  the 
detrusor  urinae,  or  in  the  heart.  It  is  an  inte- 
resting fact  that  all  the  muscles  infested  by  the 
Trichina  are  characterized  by  the  striated  ap- 
pearance of  the  ultimate  fasciculi :  while  the 
muscles  of  organic  life,  in  which  they  are 
absent,  have,  with  the  exception  of  the  heart, 
smooth  fibres,  not  grouped  into  fasciculi,  but 
reticularly  united. 

From  the  instances  of  this  parasitical  affec- 
tion of  the  human  body  which  have  already 
been  recorded,  and  from  other  unpublished 
cases  in  which  I  have  examined  the  worms, 
it  is  evident  that  their  presence  in  the  system 
is  unconnected  with  age,  sex,  or  any  particular 
form  of  disease.  They  have  been  found  in  the 
bodies  of  persons  who  have  died  of  cancer  of; 
the  penis ;  tubercles  in  the  lungs ;  exhaustion  | 
of  the  vital  powers  by  extensive  external  ul- 
ceration of  the  leg ;  fever  combined  with  tu- 
bercle^ in  the  lungs;  aneurism  of  the  aorta; 
sudden  depression  of  the  vital  powers  after  a 
comminuted  fracture  of  the  humerus ;  diar- 
rhoea. 

The  cases  which  had  occurred  before  the 
publication  of  the  first  description  of  this 
Entozoon  led  me  to  conceive  that,  although  the 
species  was  of  so  minute  a  size,  yet  the  num- 
ber of  individuals  infesting  the  body  was  so 
immense,  and  their  distribution  through  the 
muscular  system  so  extensive,  that  they  might 

*  See  Medical  Gazette,  December,  1835. 


ment  required  for  their  support;  and  I  ob- 
served "  that  it  was  satisfactory  to  believe,  that 
the  Trichina  are  productive  of  no  other  con- 
sequences than  debility  of  the  muscular  system; 
and  it  may  be  questioned  how  far  they  can  be 
considered  as  a  primary  cause  of  debility,  since 
an  enfeebled  state  of  the  vital  powers  is  the 
probable  condition  under  which  they  are 
originally  developed.  No  painful  or  incon- 
venient symptoms  were  present  in  any  of  the 
above-mentioned  cases  to  lead  the  medical 
attendants  to  suspect  the  condition  of  the  mus- 
cular system,  which  dissection  afterwards  dis- 
closed :  and  it  is  probable  that  in  all  cases  the 
patient  himself  will  be  unconscious  of  the 
presence  of  the  microscopic  parasites  which 
are  enjoying  their  vitality  at  his  expense."* 
Since  writing  the  above,  a  case  has  occurred 
in  which  the  Trichinae  were  met  with  in  the 
muscles  of  a  man  who  was  killed  while  in  the 
apparent  enjoyment  of  robust  health  by  a  frac- 
ture of  the  skull.  I  received  portions  of  the 
muscles  of  the  larynx  of  this  individual  from 
my  friend  Mr.  Curling,  Assistant-Surgeon  to 
the  London-Hospital,  who  has  recorded  the 
case  in  the  Medical  Gazette,  and  the  worms 
were  similar  in  every  respect  to  those  occurring 
in  the  diseased  subjects.  The  deduction  there- 
fore of  the  development  of  the  Trichina  being 
dependent  on  an  enfeeblement  of  the  vital 
powers  is  invalidated  by  this  interesting  ex- 
ample.f 

Leaving  now  the  consideration  of  Entozoa, 
which  from  their  minute  size  and  organization 
would  have  ranked  with  the  vast  assemblage 
of  animalcules  which  are  collected  under  the 
head  Infusoria  in  the  Regne  Animal,  we  come 
next  to  the  consideration  of  the  animals  which 
form  that  scarcely  less  heterogeneous  class,  the 
Entozoa  of  Rudolphi.  These  are  distributed  by 
that  Naturalist  into  five  orders,  which  may  be 
synthetically  arranged  and  characterized  as 
follows. 

Ordo  I.   Cystica,  Rudi.  (jtyo-Ti?)  vesica.) 
Vermes    vesiculares,  Blasenwiirmer, 
Cyst-worms  or  Hydatids. 
Char.    Body  flattened  or  rounded,  conti- 
nued posteriorly  into  a  cyst,  which  is 
sometimes  common   to  many  indivi- 
duals.   Head  provided  with  pits  (bo- 
thria  two  or  four)  or  suctorious  pores 
(four),  and  with  a  circle  of  hooklels 
sV^XA.er  with  four  unarmed   or  uncinated 
vSi^*/tentacles.     No  discernible  organs  of 
generation. 

Obs.  This  order  is  not  a  very  natural  one; 
the  species  composing  it  are  closely  allied  to  the 
Tape-worms  in  the  structure  of  the  head,  and 
when  this  is  combined  with  a  jointed  structure 
of  the  body,  as  in  the  Cysticercus  J'asciolaris 
common  in  the  liver  of  Rats,  the  small  caudal 
vesicle  forms  but  a  slight  ground  for  a  distinc- 
tion of  ordinal  importance.  The  Cystica  of 
Rudolphi  form  part  of  the  Order  Tanioidea  of 
Cuvier;  and  maybe  regarded  as  representing 

*  Zoological  Transactions,  vol.  i.  p.  315. 
t  Zool.  Trans,  vol.  i.  p.  323. 

i  2 


116 


ENTOZOA. 


the  immature  states  of  the  higher  orders  of 
Sterelmintha. 

Ordo  II.   Cestoidea,  (xscto?,  cingulum, 
uh>s,  forma.) 

Vermes    taniaformes,  Bandwurmer, 
Tape-worms. 
Char.    Body  elongated,  flattened,  soft, 
continuous,  or  articulated.   Head  either 
simply  labiate,  or  provided  with  pits 
(bothria)  or  suctorious  orifices  (oscula 
suctoria)  either  two  or  four  in  number, 
and  sometimes  with  four  retractile  un- 
armed or  uncinated  tentacles.  Andro- 
gynous generative  organs. 
Obs.    In  this  order  Rudolphi  includes  the 
inarticulated  Ligula,  with  simple  heads  un- 
provided with  bothria  or  suckers;  a  conjunc- 
tion which  detracts  from  the  natural  character 
of  the  group.     Cuvier  separates  the  Ligula 
from  the  Tania,  and  they  form  exclusively  his 
Order  Cestoidea ;  it  must  be  observed,  however, 
that  the  passage  from  the  one  to  the  other  is 
rendered  very  gradual  by  the  traces  of  bothria, 
and  of  generative  organs  which  appear  in  the 
higher  organized  Ligula  found  in  the  intestines 
of  Birds ;  and    respecting  which  Rudolphi 
hazards  the  theory  that  they  are  the  more  simple 
Ligula  of  Fishes,  developed  into  a  higher  grade 
of  structure  by  the  warmth  and  abundant  nutri- 
ment which  they  meet  with  in  the  intestines  of 
Birds  which  have  swallowed  the  Fishes  infested 
by  them. 

Oudo  III.    Them atoda,  (T^fta,  foramen, 
r^ri/ji.cc.TaS'rii  foraminosus.) 

Vermes  suctorii,  Saugwurmer,  Fluke- 
worms. 

Char.  Body  soft,  rounded,  or  flattened. 
Head  indistinct,  with  a  suctorious  fo- 
ramen ;  generally  one  or  more  suctorious 
cavities  for  adhesion  in  different  parts  of 
the  body.  Organs  of'  both  sexes  in  each 
individual. 

Obs.  This  very  natural  order  includes,  in  the 
system  of  Cuvier,  many  species  which  do  not 
infest  other  animals,  but  are  found  only  in 
fresh  waters ;  these  non-parasitic  species  form 
the  greater  part  of  the  genus  Planaria  of  Muller, 
(Jig.  80.)  Rudolphi,  who  seems  to  have  sup- 
posed the  Planaria  to  be  of  a  more  simple 
organization  than  they  truly  possess,  approxi- 
mates them  to  the  Ligulas  or  inarticulated  Ces- 
toidea. Other  naturalists,  unwilling  to  asso- 
ciate the  Planaria  with  the  Entozoa,  have 
placed  them  in  the  Class  Anellida,  but  the 
absence  of  a  ganglionic  abdominal  nervous 
chord,  of  a  floating  intestine,  and  of  an  anus, 
renders  such  an  association  very  arbitrary. 
Ordo  IV.  Acanthocepuala,  (a.jca>6a, 
spina,  x.i$a.\-n,  caput.) 

Vermes     uncinati,  Haeken-wvrmer, 
Hooked-woi^ms. 
Char.    Body  elongated,  round,  sub-elas- 
tic.   Head  with  a  retractile  proboscis 
armed  with  recurved  spines,  (Jig.  74.) 
Sexual  Organs  appropriated  to  distinct 
individuals,  male  and  female. 
Obs.    This  natural  group  includes  the  most 
noxious  of  the  internal  parasites ;  fortunately 
no  species  is  known  to  infest  the  human  body. 


They  abound  in  the  lower  animals,  and  present 
great  diversity  of  form,  some  being  cylindrical 
and  others  sacciform. 

OrdoV.  Nematoidea,  (iD^a.,Jilum,  ei^oj, 
forma.) 

Vermes  teretes,  Rund-w'urmer.  Round- 
worms. 

Char.  Body  elongated,  rounded,  elastic. 
Mouth  variously  organized  according  to 
the  genera.  A  true  intestinal  canal 
terminating  by  a  distinct  anus.  Sexes 
distinct. 

Obs.  The  internal  character  which  Rudolphi 
has  introduced  in  his  definition  of  this  Order,* 
viz.  that  derived  from  the  structure  of  the  ali- 
mentary canal,  its  free  course  through  the  body, 
and  its  termination  by  a  distinct  anus  at  the 
extremity  opposite  the  mouth,  is  one  of  much 
greater  value  than  any  of  the  external  modifica- 
tions of  the  body  which  characterize  the  four 
preceding  orders.  It  is,  in  fact,  a  trait  of  or- 
ganization which  is  accompanied  by  corre- 
sponding modifications  of  other  important 
parts,  more  especially  the  nervous  system. 

The  Entozoa  which  manifest  this  higher  type 
of  structure  form  in  the  syslem  of  Cuvier  a 
group  equivalent  to  that  which  is  constituted 
by  the  four  other  orders  combined.  The  En- 
tozoa composing  the  first  four  orders  above 
characterized  have  no  distinct  abdominal  cavity 
or  intestine,but  the  digestive  function  is  carried 
on  in  canals  without  an  anal  outlet  excavated 
in  the  parenchymatous  substance  of  the  body, 
and  Cuvier  accordingly  denominates  them  the 
Vers  intestinaux  parenchymateux.  The  Ne- 
matoidea, with  which  Cuvier  rightly  associates 
the  genus  Pentastoma  of  Rudolphi,  and  also 
(but  less  naturally)  the  Vers  rigidules  of  La- 
marck, or  Epizoa,  he  denominates  '  Vers  intes- 
tinaux cavitaires.' 

With  respect  to  the  Epizoa,  or  the  external 
Lerna?an  parasites  of  Fishes,  although  they 
agree  with  the  Nematoidea  and  all  inferior 
Entozoa  in  the  absence  of  distinct  respiratory 
organs,  yet  the  ciliated  natatory  members  which 
they  possess  in  the  young  state,  and  the  exter- 
nal ovarian  appendages  of  the  adult,  are  cha- 
racters which  raise  them  above  the  Entozoa  as 
a  distinct  and  higher  class  of  animals,  having 
intimate  relations  with  the  soft-skinned  Sipho- 
nostomous  Crustaceans. 

Limiting,  then,  the  Cavitary  Entozoa  to  the 
Nematoidea  of  Rudolphi,  and  the  Genera  Lin- 
guatula,  Pentastoma,  Porocephulus,  and  Syn- 
gamus,  which,  under  the  habit  of  Cestoid  or 
Trematode  Worms,  mask  a  higher  grade  of 
organization,  we  propose  to  regard  them  as  a 
group  equivalent  to  the  Sterelmintha,  and  to 
retain  for  them  the  name  of  Ctzlelmintha. 

The  class  of  Entozoa  thus  constituted  em- 
braces already  the  types  of  three  different 
orders,  of  which  one  is  formed  by  the  Nema- 
toidea of  Rudolphi,  a  second  has  been  esta- 
blished by  Diesing  for  the  genus  Pentastoma 
and  its  congeneric  forms,  under  the  name  of 

*  "  Corpus  teres  elasticum,  tractus  intestinalis 
hinc  ore,  illinc  ano  terminatus.  Alia  individua 
mascula,  alia  feminea. "Synops.  Entox.  p.  3. 


ENTOZOA. 


117 


Acanthotheca ;  and  the  singular  organization 
of  the  Syngamus  of  Siebold,  presently  to  be 
described,  clearly  indicates  the  type  of  a  third 
order  of  Cavitary  Entozoa. 

As  a  short  description  has  already  been 
given  of  the  species  of  Protelmintha  which 
inhabit  the  human  body,  we  shall  proceed  to 
notice  those  species  belonging  to  the  two  di- 
visions of  Entozoa  above  defined,  which  have 
a  similar  locality,  before  entering  upon  the 
organization  of  the  class  generally. 

The  first  and  simplest  parasite  which  de- 
mands our  attention  is  the  common  globular 
Hydatid,  which  is  frequently  developed  in  the 
substance  of  the  liver,  kidney,  or  other  abdo- 
minal viscera,  and  occasionally  exists  in  prodi- 
gious numbers  in  dropsical  cysts  in  the  human 
subject. 

Considerable  diversity  of  opinion  still  exists 
as  to  the  nature  of  these  ambiguous  productions, 
to  which  Laennec  first  gave  the  name  of  Ace- 
phalocysts ;  we  shall  nevertheless  admit  them 
into  the  category  of  human  parasites,  for  reasons 
which  are  stated  in  the  following  descrip- 
tion. 

The  Acephalocyst  is  an  organized  being, 
consisting  of  a  globular  bag,  which  is  com- 
posed of  condensed  albuminous  matter,  of  a 
laminated  texture,  and  contains  a  limpid  co- 
lourless fluid,  with  a  little  albuminous  and  a 
greater  proportion  of  gelatinous  substance. 

The  properties  by  which  we  recognize  the 
Acephalocyst  as  an  independent  or  individual 
organized  being  are,  first,  growth,  by  intrinsic 
power  of  imbibition ;  and,  secondly,  reproduc- 
tion of  its  species  by  gemmation.  The  young 
Acephalocysts  are  developed  between  the  layers 
of  the  parent  cyst,  and  thrown  off  either  inter- 
nally or  externally  according  to  the  species. 

As  the  best  observers  agree  in  stating  that 
the  Acephalocyst  is  impassive  under  the  appli- 
cation of  stimuli  of  any  kind,  and  manifests 
no  contractile  power  either  partial  or  general, 
save  such  as  evidently  results  from  elasticity, 
in  short,  neither  feels  nor  moves,  it  cannot,  as 
the  animal  kingdom  is  at  present  characterized, 
be  referred  to  that  division  of  organic  nature. 

It  would  then  be  a  question  how  far  its 
chemical  composition  forbids  us  to  rank  the 
Acephalocyst  among  vegetables.  In  this  king- 
dom it  would  obviously  take  place  next  those 
simple  and  minute  vesicles,  which,  in  the 
aggregate,  constitute  the  green  matter  of 
Priestly,  ( Protococcus  viridis,  Agardh ;)  or 
those  equally  simple  but  differently  coloured 
Psychodiaria,  which  give  rise  to  the  red 
snow  of  the  Arctic  regions,  (Protococcus  Ker- 
mesianus.)  These  "  first-born  of  Flora''  con- 
sist in  fact  of  a  simple  transparent  cyst,  and 
propagate  their  kind  by  gemmules  developed 
from  the  external  surface  of  the  parent. 

Or  shall  we,  from  the  accidental  circum- 
stance of  the  Acephalocyst  being  developed 
in  the  interior  of  animal  bodies,  regard  it,  as 
Rudolphi  would  persuade,  in  the  same  light 
as  an  ulcer,  or  pustule, — as  a  mere  morbid  pro- 
duct? 

The  reasons  assigned  by  the  learned  Pro- 


Acephalocystis  endogena. 


fessor*  do  induce  us  to  consider  the  Acephalo- 
cyst as  a  being  far  inferior  in  the  scale  of  orga- 
nization to  the  Cysticercus;  but  still  not  the  less 
as  an  independent  organized  species,  sharing  its 
place  of  development  and  sphere  of  existence 
in  common  with  the  rest  of  the  Entozoa. 

Acephulocystis  endogena.    Pill-box  Hydatid 
of  Hunter,  (fig.  56).    This  species  is  so  called 
from    the  circum- 
Fig.  56.  stance  of  the  gem- 

mules  being  detach- 
ed from  the  internal 
surface  of  the  cyst, 
where  they  grow, 
and,  in  like  man- 
ner, propagate  their 
kind,  so  that  the 
successive  genera- 
tions produce  the 
appearance  descri- 
bed by  Hunter  and 
other  pathologists. 
The  membrane 
of  the  cyst  is  thin,  delicate,  transparent,  or 
with  a  certain  pearly  semi-opacity;  it  tears 
readily  and  equally  in  every  direction,  and 
can,  in  large  specimens,  be  separated  into 
lamina;.  The  phenomenon  of  endosmose  is 
readily  seen  by  placing  the  recent  Acepha- 
locyst in  a  coloured  liquid,  little  streams  of 
which  are  gradually  transmitted  and  mingle 
with  the  fluid  of  the  parasite.  The  vesicles  or 
gemmules,  developed  in  the  parietes  of  the 
cyst,  may  be  observed  of  different  sizes,  some 
of  microscopic  dimensions,  others  of  a  line  in 
diameter  before  they  are  cast  off,  see  fig.  56, 
where  a  shows  the  laminated  membrane,  b  the 
minute  Acephalocysts  developed  between  its 
layers. 

The  Acephalocyst  of  the  Ox  and  other  Ru- 
minant Animals  differs  from  that  of  the  Hu- 
man Subject  in  excluding  the  gemmule  from  the 
external  surface,  whence  the  species  is  termed 
Acephulocystis  exogena  by  Kuril.  Both  kinds 
are  contained  in  an  adventitious  cyst,  com- 
posed of  the  condensed  cellular  substance  of 
the  organ  in  which  they  are  developed. 

The  Genus  Echinococcus  is  admitted  by 
Rudolphi  into  the  Order  Cystica,  less  on  ac- 
count of  the  external  globular  cyst,  which, 
like  the  Acephalocyst,  is  unprovided  with  a 
head  or  mouth,  than  from  the  structure 
of  the  minute  bodies  which  it  contains, 
and  which  are  described  as  possessing  the 
armed  and  suctorious  head  characteristic  of 
the  Ccenuri  and  Cysticerci.  It  must  be  ob- 
served that  Rudolphi-f  does  not  ascribe  this 

*  Mihi,  quidem,  ea  tandem  hydatis  animal 
vivum  vocatur,  qua?  vitam  propriam  degit  uti  Cys- 
ticerci, Coenuri,  &c.  Quae  autem  organismi  alieni 
( v.  c.  humani)  particulum  efficit  animal,  me 
judice,  dici  nequit.  Mortua  non  est,  quamdiu 
organismi  partem  sistit,  uti  etiam  ulcus,  pustula, 
efflorescentia  ;  sed  haec  ideo  non  sunt  animalia. — ■ 
Synops.  Entoz.  p.  551. 

t  Vermiculi  globosi,  subglobosi,  obovati,  obcor- 
dati,  etc.;  pro  capite  plus  minus  vel  exserto  vel 
rctracto;  posticc  mox  obtusissimi,  mox  obtusi,  mox 
acuti.    Corona  uncinulorum,   uti  vidctur,  duplex. 


118 


ENTOZOA. 


complicated  structure  to  the  vermiculi  of  the 
Human  Echinococcus  on  his  own  authority, 
and  speaks  doubtfully  respecting  the  coronet 
of  hooklets  and  suctorious  mouths  of  the  ver- 
miculi contained  in  the  cyst  of  the  Echinococcus 
of  the  Sheep,  Hog,  &c. 

The  Echinococcus  hominis,  (Jig.  57,)  which 
occurs  in  cysts  in  the 
Fig.  57.  liver,  spleen,  omen- 

tum, or  mesentery,  is 
composed  ofan  exter- 
nal yellow  coriace- 
ous, sometimes  crus- 
taceous  tunic,  and  an 
internal  transparent, 
firm,  gelatinous 
membrane.  The  form 
of  the  contained  ver- 
miculi is  represented 
in  the  magnified  view 
subjoined,  (fig.  58,)  taken  from  the  Elminto- 
grafia  humuna  of  Delle  Chiaje. 

Fig.  58. 


Echinococcus  hominis. 


Vermictcfi  ofi Echinococcus  hominis,  highly  magnified 


Miiller*\fe!&.  recently  described  a  species  of 
Echinococ^svgaded  with  the  urine  by  a  young 
man  labouring  under  symptoms  of  renal  disease. 
The  tunfe  of  the  containing  cyst  was  a  thick 
white  membrane,  not  naturally  divided  into 
laminse;  th&Wiimalcules  floating  in  the  con- 
tained fluid  presented  a  circle  of  hooklets  and 
four  obtuse  processes  round  the  head  ;  the  pos- 
terior end  of  the  body  obtuse :  some  of  thenj 
were  inclosed  in  small  vesicles  floating  in  the 
large  one ;  others  presented  a  filamentary  pro- 
cess at  their  obtuse  end,  probably  a  connecting 
pedicle  which  had  been  broken  through. 

Of  the  species  entitled  Echinococcus  veteri- 
norum  we  have  carefully  examined  several  in- 
dividuals soon  after  they  were  extracted  from 
the  recently-killed  animal,  (a  sow,  in  which 
they  existed  in  great  abundance  in  cysts  in  the 
abdomen.)  The  containing  cysts  were  com- 
posed of  two  layers,  artificially  separable, 
both  of  a  gelatinous  texture,  nearly  colourless 
and  subtransparent,  the  external  one  being  the 
firmest.  The  contained  fluid  was  colourless 
and  limpid,  with  a  few  granular  bodies  floating 

Oscula  suetoria  quatuor  ;  an  haec  in  omnibus  ?  Ipse 
saltern  in  suis  Echinococcis  non  vidi,  set!  dum  Be- 
rolini  recens  examinarem,  microscopio  solito  et 
bono  destitutes  erara. —Hist.  Entoz. 

*  Archiv  fur  Physiol.  (Jahresbcricht),  1836. 


in  it,  and  immense  numbers  of  extremely  mi- 
nute particles  applied  but  not  adherent  to  the 
internal  surface  of  the  cyst.  On  examining 
these  particles  with  a  high  magnifying  power, 
they  were  seen  to  be  living  animalcules  of  an 
ovate  form,  moving  freely  by  means  of  superfi- 
cial vibratile  cilia,  having  an  orifice  at  the  smaller 
end  from  which  a  granular  and  glairy  substance 
was  occasionally  discharged,  and  a  trilobate  de- 
pression at  the  greater  and  anterior  extremity 
produced  by  the  retraction  of  part  of  the  body. 
I  watched  attentively  and  for  a  long  period  a 
number  of  these  animalcules  in  the  hope  of 
seeing  the  head  completely  protruded,  but  with- 
out success.  On  compressing  the  animalcula 
between  plates  of  glass,  a  group  of  long,  slen- 
der, straight,  sharp-pointed  spines  became  vi- 
sible within  the  body,  at  its  anterior  part,  and 
directed  towards  the  anterior  depression,  pre- 
cisely resembling  the  parts  described  and  fi- 
gured by  Ehrenberg  as  the  teeth  of  the  Poly- 
gastric  Infusories ;  the  rest  of  the  body  was 
occupied  by  large  clear  globules,  the  stomachs  ? 
and  smaller  granules.  Animalcules  thus  orga- 
nized, it  is  evident,  cannot  be  classed  with  cystic 
Entozoa,  but  must  be  referred  to  the  Polygastric 
Infusoria, 

The  globular  cyst  which  is  commonly  deve- 
loped in  the  brain  of  Sheep  differs  from  the 
Echinococcus  in  having  organically  attached  to 
itanumber  of  small  vermiform  appendages,  pro- 
vided severally  with  suctorious  orifices,  and  an 
uncinated  rostellum,  similar  to  those  in  the  head 
of  the  Armed  Tanis.  But  as  this  cystic  genus, 
denominated  Canurus,  (xonof,  communis,  av^oc, 
cauda,  from  the  terminal  cyst  being  common 
to  many  bodies  and  heads,)  is  not  met  with  in 
the  human  subject,  a  simple  notice  of  it  is  here 
sufficient. 

When  the  dilated  cyst  forms  the  termina- 
tion of  a  single  Entozoon,  organized  as  above 
described,  it  is  termed  Cysticercus,  (xvotk, 
vesica,  xipx.of,  cauda),  and  of  this  genus  there 
are  several  species,  distinguished  for  the 
most  part  by  the  forms  and  proportions  of 
the  neck  or  body  intervening  between  the 
head  and  the  cyst ;  as  for  example,  the  Cyst. 
J'asciolaris,  Cyst,  fistularis,  Cyst,  longicoltis, 
Cyst,  tenuicollis,  &c.  The  only  species  of 
this  genus  known  to  infest  the  human  body 
is  the  Cysticercus  cellulose,  Rud.  (the  Hydatis 
Finna  of  Blumenbach).  It  is  developed, 
like  the  Trichina,  in  the  interfascicular  cel- 
lular tissue  of  the  muscles,  and,  like  it,  is  in- 
variably surrounded  by  an  adventitious  cap- 
sule of  the  surrounding  substance  condensed 
by  the  adhesive  inflammation.    Fig.  59  exhi- 

Fig.  59. 


Portion  of  human  muscle,  with  Cysticercus  cdluloscc. 


EWTOZOA. 


119 


bits  a  portion  of  muscle  thus  infested;  a  the 
adventitious  cyst  laid  open,  exposing  the  Hy- 
datid; a'  the  adventitious  cyst  elongated  by  the 
extension  of  the  head  and  neck  of  the  inclosed 
hydatid  b  in  the  direction  of  the  muscular  fibres. 
The  cysticercus  itself  sometimes  attains  the  size 
exhibited  in  Jig.  60,  in  which  a  indicates  the 


Fig.  60.  Fig.  61. 


Magnified  head  of  Cysticerus  celluloses. 

head,  b  the  neck  or  body,  and  c  the  dilated 
vesicular  tail.  Fig.  61  exhibits  the  head 
sufficiently  magnified  to  show  the  uncinated 
rostellum  or  proboscis  d  for  irritation  and 
adhesion,  and  the  suctorious  discs  e  e  for  im- 
bibing the  surrounding  nutriment. 

The  occurrence  of  this  Entozoon  in  the  Hu- 
man Subject  appears  to  be  less  common  in  this 
country  than  on  the  Continent.  In  the  course 
of  five  years  we  have  become  acquainted  with 
only  two  cases,  one  in  a  subject  at  the  Dis- 
secting-Rooms  of  St.  Bartholomew's,  the  other 
in  a  subject  at  the  Webb-street  School  of  Ana- 
tomy. Rudolphi  relates  that  out  of  two  hun- 
dred and  fifty  bodies  dissected  annually  at  the 
Anatomical  School  of  Berlin,  from  four  to  five 
were  found  through  nine  consecutive  years  to 
be  infested  more  or  less  copiously  with  the 
Cysticercus  cellulose;  for  the  most  part  the 
subjects  had  been  of  the  leucophlegmatic 
temperament,  but  not  affected  with  ascites  or 
anasarca.  The  muscles  most  obnoxious  to 
the  Entozoon  in  question  are  the  glutcei,  psoas, 
iliacus  internus,  and  the  extensors  of  the  thigh; 
they  have  been  found  also  in  the  muscular 
tissue  of  the  heart,  and  in  parts  not  muscular, 
as  the  brain  and  eye.  Soemmering  detected 
one  specimen  of  the  Cysticercus  cellulose 
in  the  anterior  chamber  of  the  eye  of  a  young 
woman  a;t.  18.*  The  following  is  a  more  re- 
cent account  of  a  specimen  which  was  deve- 
loped in  the  anterior  chamber  of  the  eye  of  a 
patient  in  the  Glasgow  Ophthalmic  Infirmary. 

"  Case. — From  the  month  of  August,  1832, 
till  about  the  middle  of  January,  1833,  when 
she  was  first  brought  to  Mr.  Logan,  the  child 
had  suffered  repeated  attacks  of  inflammation 
in  the  left  eye.  Mr.  L.  found  the  cornea  so 
nebulous,  and  the  ophthalmia  so  severe,  that  he 
dreaded  a  total  loss  of  sight.  He  treated  the 
case  as  one  of  scrofulous  ophthalmia;  and  after 
the  use  of  alterative  medicines,  and  the  appli- 
cation of  a  blister  behind  the  ear,  the  inflam- 

*  See  Isis,  1830,  p.  717,  as  quoted  by  Norc'- 
mann,  Mikrographisrhe  Beitrage  zur  Naturgcschicte 
tier  wirbellosen  thiere. 


matory  symptoms  subsided,  leaving,  however, 
a  slight  opacity  of  the  lower  part  of  the  cornea. 
After  a  week,  the  child  was  again  brought  to 
Mr.  L.,  who,  on  examining  the  eye,  disco- 
vered, to  his  great  surprise,  a  semitransparent 
body,  of  about  two  lines  in  diameter,  floating 
unattached  in  the  anterior  chamber.  This 
body  appeared  almost  perfectly  spherical,  ex- 
cept that  there  proceeded  from  its  lower  edge 
a  slender  process,  of  a  white  colour,  with  a 
slightly  bulbous  extremity,  not  unlike  the  pro- 
boscis of  a  common  fly.  This  process  Mr.  L. 
observed  to  be  of  greater  specific  gravity  than 
the  spherical  or  cystic  portion,  so  that  it  always 
turned  into  the  most  depending  position.  He 
also  remarked  that  it  was  projected  or  elongated 
from  time  to  time,  and  again  retracted,  sp  as 
to  be  completely  hid  within  the  cystic  portion  ; 
while  this,  in  its  turn,  assumed  various  changes 
of  form,  explicable  only  on  the  supposition  of 
the  whole  constituting  a  living  hydatid. 

"  On  the  3d  April,  when  I  examined  the  case, 
I  found  the  cornea  slightly  nebulous,  the  eye 
free  from  inflammation  and  pain,  and  the  ap- 
pearances and  movements  of  the  animal  exactly 
such  as  described  by  Mr.  Logan.  When  the 
patient  kept  her  head  "at  rest,  as  she  sat  before 
me,  in  a  moderate  light,  the  animal  covered 
the  two  lower  thirds  of  the  pupil.  Watching 
it  carefully,  its  cystic  portion  was  seen  to  be- 
come more  or  less  spherical,  and  then  to  assume 
a  flattened  form,  while  its  head  I  saw  at  one 
moment  thrust  suddenly  down  to  the  bottom 
of  the  anterior  chamber,  and  at  the  next  drawn 
up  so  completely  as  scarcely  to  be  visible.  Mr. 
Meikle  turned  the  child's  head  gently  back, 
and  instantly  the  hydatid  revolved  through  the 
aqueous  humour,  so  that  the  head  fell  to  the 
upper  edge  of  the  cornea,  now  become  the 
more  depending  part.  On  the  child  again 
leaning  forwards,  it  settled  like  a  little  balloon 
in  its  former  position,  preventing  the  patient 
from  seeing  objects  directly  before  her,  or 
below  the  level  of  the  eye,  but  permitting  the 
vision  of  such  as  were  placed  above.  Mr. 
Logan  had  observed  no  increase  of  size  in  the 
animal  while  it  was  under  his  inspection.  Mr. 
Meikle  had  watched  it  carefully  for  three  weeks 
without  observing  any  other  change  than  a 
slight  increase  in  the  opacity  of  the  cystic 
portion. 

"  To  every  one  who  had  seen  or  heard  of  Mr. 
Logan's  case,  the  question  naturally  occurred, 
Ought  not  this  animal  to  be  removed  from  the 
eye?  Mr.  Logan  and  Mr.  Meikle  appeared  to 
have  deferred  employing  any  means  for  destroy- 
ing or  removing  it ;  first,  because  it  seemed  to 
be  producing  no  mischief :  and,  secondly,  be- 
cause there  was  a  probability  that  it  was  a 
short-lived  animal,  and  likely  therefore  speedily 
to  perish  and  shrink  away,  so  as  to  give  no 
greater  irritation  than  a  shred  of  lenticular 
capsule.  Various  means  naturally  suggested 
themselves  for  killing  the  animal,  such  as 
passing  electric  or  galvanic  shocks  through  the 
eye,  rubbing  in  oil  of  turpentine  round  the 
orbital  region,  giving  this  medicine  internally 
in  small  doses,  or  putting  the  child  on  a  course 
of  sulphate  of  quiua,  or  some  other  vegetable 


120 


ENTOZOA. 


bitter  known  to  be  inimical  to  the  life  of  the 
Entozoa.  As  the  patient  appeared  to  be  in 
perfect  health,  it  was  natural  to  suppose  that 
the  other  organs  were  free  from  hydatids,  and 
that  a  change  of  diet  would  have  little  or  no 
effect  upon  the  solitary  individual  in  the  aque- 
ous humour.  Had  she,  on  the  contrary,  pre- 
sented a  cachectic  constitution,  with  pale  com- 
plexion, tumid  belly,  debility,  and  fever,  none 
of  which  symptoms  were  present,  we  should 
have  been  led  to  suspect  that  what  was  visible, 
in  the  eye  was  but  a  sample  of  innumerable 
hydatids  in  the  internal  parts  of  the  body,  and 
might  have  recommended  a  change  of  diet, 
with  some  hopes  of  success.  In  the  course  of  six 
weeks  after  I  saw  the  patient,  the  cysticercus 
having  enlarged  in  size,  the  vessels  of  the  con- 
junctiva and  sclerotica  became  turgid,  the  iris 
changed  in  colour,  and  less  free  in  its  motions, 
while  the  child  complained  much  of  pain  in  the 
eye ;  it  was  decided  that  the  operation  of  ex- 
traction should  be  attempted,  and  I  owe  to 
Dr.  Robertson  of  Edinburgh,  who  operated,  the 
communication  of  the  following  particulars. 
The  incision  of  the  cornea  was  performed  with- 
out the  slightest  difficulty,  but  no  persuasion 
or  threats  could  induce  the  child  again  to  open 
the  eye ;  she  became  perfectly  unruly,  and  the 
muscles  compressed  the  eye-ball  so  powerfully 
that  the  lens  was  forced  out,  and  the  hydatid 
ruptured.  The  patient  was  put  to  bed  in  this 
state.  In  the  evening  Dr.  R.  succeeded  in 
getting  the  girl  to  open  the  eyelids,  when  with 
the  forceps  he  extracted  from  the  lips  of  the 
incision  the  remains  of  the  animal  in  shreds, 
it  being  so  delicate  as  scarcely  to  bear  the 
slightest  touch.  A  portion  of  the  iris  remained 
in  the  wound,  which  nothing  would  induce  the 
girl  to  allow  Dr.  R.  to  attempt  to  return. 

"  After  the  eye  healed,  the  cornea  remained 
clear,  except  at  the  cicatrice,  where  it  was  only 
semitransparent;  the  pupil,  in  consequence  of 
adhesion  to  the  cicatrice,  was  elliptical,  and  the 
opaque  capsule  of  the  lens  occupied  the  pu- 
pillary aperture.  The  patient  readily  recog- 
nized the  presence  of  light." 

The  Cysticercus  cellulosa  occurs  also  in 
quadrupeds,  and  is  found  most  commonly  and 
in  greatest  abundance  in  the  Hog,  giving  rise 
to  that  state  of  the  muscles  which  is  called 
"  measly  pork." 

Of  the  Cestoid  Ol  der  of  Entozoa  two  species 
belonging  to  different  genera  infest  the  Hu- 
man Body.  The  Swiss  and  Russians  are 
troubled  with  the  Bo'thriocephdlus  latus;  the 
English,  Dutch,  and  Germans  with  the  Tama 
solium :  both  kinds  occur,  but  not  simulta- 
neously in  the  same  individual,  in  the  French. 
It  is  not  in  our  province  to  dwell  upon  the 
medical  remedies  for  these  parasites,  but  we 
may  observe  that  the  old  vermifuge  mentioned 
by  Celsus,  viz.  the  bark  of  the  pomegranate,  is 
equally  efficacious  and  safer  perhaps  than  the 
oleum  terebinthina  commonly  employed  in 
this  country  for  theexpulsion  of  theTape-worm. 

From  the  singular  geographical  distribution, 
as  it  may  be  termed,  of  the  above  Cestoid 
parasites,  the  Bothriocepnalui  latus  rarely  falls 
under  the  observation  of  the  English  Enlozoo- 


logist.    It  may  be  readily  distinguished  from 
the  Tenia  solium  by  the  form  of  the  segments, 
which  are  broader  than  they  are  long,  and  by 
the  position  of  the  genital  pores,  which  occur 
in  a  series  along  the  middle  of  one  of  the  flat- 
tened surfaces  of  the  body,  and  not  at  the  mar- 
gin of  each  segment  as  in  the  Tania  solium. 
The  head,  which  was  for  a  long  time  a  deside- 
ratum in  natural  history,  has  at  length  been  dis- 
covered by  Bremser.  It  is  of  an  elongated  form, 
two-thirds  of  a  line  in  length,  and  presents,  in- 
stead of  the  four  round  oscula 
Fig.  62.        characteristic  of  the  true  Tania, 
two  lateral  longitudinal  fossae, 
or  bothria,  ( a  a,  Jig.  62,  which 
is  a  highly-magnified  view  of 
the  head  of  the  Bothrioce- 
phalus  latus.) 

The  Tania  solium  (Jig.  63) 
attains  the  length  of  from  four 
to  ten  feet,  and  has  been  ob- 
served to  extend  from  the  pylo- 
rus to  within  seven  inches  of 
the  anus  of  the  human  intes- 
tine.*   Its  breadth  varies  from 
one-fourth  of  a  line  at  its  an- 
terior part  to  three  or  four 
lines  towards  the  posterior  part 
of  the  body,  which  then  again 
diminishes.  The  head  is  small, 
Head  of  Bothrio-    and  generally  hemispherical, 
cephalm  latus    broader  than  long,  and  often 
magnified.         as  if  truncated  anteriorly :  the 

Fie  63. 


Tcenia  solium,  two-thirds  natural  sixe.  \ 

*  See  Robin,  in  J  urnal  de  Medecinc,  torn.  xxv. 
(1766),  p.  222. 


ENTOZOA. 


121 


four  mouths,  or  oscula,  are  situated  on  the 
anterior  surface,  ( a,  Jig.  63,)  and  surround 
the  central  rostellum,  which  is  very  short,  termi- 
nated by  a  minute  apical  papilla,  and  surround- 
ed by  a  double  circle  of  small  recurved  hooks. 
The  segments  of  the  neck,  or  anterior  part  of  the 
body,  are  represented  by  transverse  rugae,  the 
marginal  angles  of  which  scarcely  project  be- 
yond the  lateral  line ;  the  succeeding  seg- 
ments are  subquadrate,  their  length  scarcely 
exceeding  their  breadth,  they  then  become  sen- 
sibly longer,  narrower  anteriorly,  thicker  and 
broader  at  the  posterior  margin,  which  slightly 
overlaps  the  succeeding  joint ;  the  last  series  of 
segments  are  sometimes  twice  or  three  times  as 
long  as  they  are  broad.  The  generative  orifices 
(b,  b)  are  placed  near  the  middle  of  one  of  the 
margins  of  each  joint,  and  are  generally  alter- 
nate. 

The  Tania  solium  is  subject  to  many  varieties 
of  form  or  malformations;  the  head  has  been  ob- 
served to  present  six  oscula  instead  of  four.  In 
the  Imperial  Museum  at  Vienna,  so  celebrated 
for  its  entozoological  collection,  there  is  a  por- 
tion of  a  Tania  solium,  of  which  one  of  the 
margins  is  single  and  the  other  double,  as  it 
were  two  taeniae  joined  by  one  margin.  In  the 
Museum  of  the  College  of  Surgeons  is  preserved 
a  fragment  of  the  Tsema  solium  of  unusual  size; 
it  swells  out  suddenly  to  the  breadth  of  three- 
fourths  of  an  inch  with  a  proportionate  degree 
of  thickness,  and  then  diminishes  to  the  usual 
breadth.* 

The  species  of  Tania  infesting  the  intestines 
of  other  animals  are  extremely  numerous,  ne- 
vertheless they  are  rare  in  Fishes,  in  which  they 
seem  to  be  replaced  by  the  Bothriocephali  and 
Ligulte.  The  determination  of  the  species  in 
this,  as  in  every  other  natural  and  circumscribed 
genus,  is  extremely  difficult  and  often  uncer- 
tain :  their  study  is  facilitated  by  distributing 
them  into  the  three  following  sections,  of  which 
the  first  includes  those  species  which  are  de- 
prived of  a  proboscis,  Teenia  inermes ;  the 
second  those  which  have  a  proboscis,  but  un- 
armed, T&n'ue  rostellata ;  the 
third  the  Tape-worms  with  an 
uncinated  proboscis,  Tania  ar- 
viatcE. 

The  Trematode  Order,  which 
is  the  most  extensive  division  of 
the  Parenchymatous  class  of  En- 
tozoa,  and  embraces  the  greatest 
number  of  generic  forms,  in- 
cludes only  two  species  infesting 
the  human  body,  one  of  which, 
the  liver-fluke  (Distoma  hepati- 
cum ),  is  extremely  rare,  and  the 
other  ( Polystoma  Pinguicola) 
somewhat  problematical. 

The  Distoma  heputicum  (Jig. 
64)  is  found  in  the  gall-bladder 
and  ducts  of  the  liver  of  a  variety 
of  quadrupeds,  and  very  com- 
monly in  the  Sheep.  When  it 
occurs  in  the  Human  species,  it 
is  generally  developed  in  the 

Sec  Catal.  of  Nat.  Hist.  No.  216. 


Fig.  64. 


same  locality.  The  form  of  this  species  of  En- 
tozoa  is  ovate,  elongate,  flattened ;  the  anterior 
pore  or  true  mouth  (a)  is  round  and  small,  the 
posterior  cavity  (b),  which  is  imperforate  and 
subservient  only  to  adhesion  and  locomotion, 
is  large,  transversely  oval,  and  situated  on  the 
ventral  surface  of  the  body  in  the  anterior 
moiety.  Between  these  cavities  there  is  a  third 
orifice  (c)  exclusively  destined,  like  the  orifice 
on  each  joint  of  the  Taenia,  to  the  generative 
system ;  and  from  which  a  small  cylindrical 
process,  or  lemniscus,  is  generally  protruded  in 
the  full-sized  specimens. 

The  form  of  the  body  is  so  different  in  the 
young  Distomata,  that  Rudolphi  was  induced 
to  believe  the  specimens  from  the  human  gall- 
bladder which  were  in  this  state,  to  belong  to 
a  distinct  species,  which  he  termed  lanceo- 
latum  ;  this  modification,  which  is  wholly  de- 
pendent upon  age,  is  shown  in  the  subjoined 
figure ;  and  we  shall  hereafter  have  to  notice  the 
more  extraordinary  changes,  amounting  to  a 
metamorphosis,  which  the  Distomata  infesting 
the  intestines  of  Fish  undergo. 

The  Polystoma  Pinguicola  was  discovered 
by  Treutler,  in  the  cavity  of  an  indurated  adi- 
pose tubercle,  in  the  left  ovarium  of  a  female, 
aetat.  20 ;  it  is  represented  in  situ,  at  A,  Jig.  62. 

Its  natural  size  and  shape 
is  shewn  at  B,  the  body  is 
depressed,subconvex  above, 
concave  below,  subtruncate 
anteriorly,  a  little  contracted 
behind  the  head,  pointed  at 
the  posterior  extremity.  On 
the  under  side  of  the  head 
C,  there  are  six  orbicular 
pores  disposed  in  a  semi- 
lunar form  :  a  larger  sucto- 
rious  cavity  occurs  on  the 
ventral  aspect  at  the  begin- 
ning of  the  tail  (b  B),  and  a 
small  orifice  is  situated  at 
the  apical  extremity. 

A  second  species  of  Po- 
lystoma (Polystoma  Vena- 
rum  ),  stated  by  Treutler  to 
have  been  situated  in  the 
anterior  tibial  vein  of  a  Man, 
which  was  accidentally  ruptured  while  bathing, 
is  generally  supposed  to  have  belonged  to  a 
species  of  Planaria,  and  to  have  been  acci- 
dentally introduced  into  the  strange  locality 
above-mentioned . 

The  worms  of  the  Trematode  order  are  those 
which  are  most  frequent  in  the  interior  of  the 
eyes  of  different  animals,  perhaps  the  most 
singular  situation  in  which  Entozoa  have  as  yet 
been  found,  and  respecting  which  much  in- 
teresting information  has  recently  been  given 
by  Ur.  Nordmann,  in  the  first  part  of  his 
beautiful  work  entitled  "  Mikrographische 
Beitrage  zur  Naturgeschicte  der  Wirbellosen 
Thiere."  Of  the  species  described  and  figured 
in  that  work,  we  have  selected  for  illustration 
the  Diplostomum  volvens. 

Fig.  66  exhibits  a  magnified  view  of  the 
vitreous  humour  of  a  Perch  ( Percujluviutilis, 
Linn.)  containing  numerous  specimens  of  fchis 


Polystoma 
Pinguicola. 


122 


ENTOZOA. 


Fig.  66. 


Diplostomum  volvens  in  the  eye  of  a  Perch. 

parasite,  which  sometimes  exists  in  such  pro- 
digious numbers,  that  the  cavity  of  the  eyeball 
is  almost  exclusively  filled  by  them.  They 
not  only  infest  the  vitreous  but  also  the  aqueous 
humours,  and  have  been  found  in  the  choroid 
gland. 

All  the  species  of  Diplostomum  are  very 
small,  seldom  exceeding  a  sixth  part  of  a  line 
in  length.  They  resemble  the  genus  Distoma, 
and  present  some  affinity  to  the  Cercaria, 
which  infest  the  fresh-water  Snails ;  but  they 
have  characters  peculiar  to  themselves  which 
entitle  them  to  rank  as  a  distinct  genus ;  of 
these  the  principal  external  one  is  the  addi- 
tional sucker  developed  on  the  ventral  aspect 
of  the  body,  as  compared  with  Distoma, 
whence  Nordmann  calls  the  genus  Diplosto- 
mum, though  Diplo-cott/lus  would  be  the  more 
appropriate  designation,  since,  as  before  ob- 
served, the  ventral  depressions  are  simply 
organs  of  adhesion,  and  have  no  communication 
with  the  alimentary  canal.  Besides  the  suckers 
the  Diplostomum  has  an  anterior  mouth  f  a,  jig. 
81),  as  in  the  Distoma.  The  first  or  anterior 
sucker  (b,Jig.  81 )  is  twice  the  size  of  the  mouth; 
and  the  second  ( c,jig.  81)  is  again  double  the 
size  of  the  former.  As  the  figure  shows  the 
vessels  from  the  dorsal  aspect,  these  suckers 
can  only  be  seen  in  outline.  The  animal  has 
great  power  over  them  and  can  contract  the 
parenchyma  of  the  body  surrounding  them, 
so  as  to  make  them  project  like  rudimental 
extremities  from  the  ventral  surface. 

It  has  been  already  observed  that  no  species 
of  the  Acanthocephalous  order  of  Entozoa  has 
hitherto  been  found  in  the  Human  body,  the 
illustration  of  this  form  of  the  Sterelmintha 
will  therefore  be  confined  to  the  section  treat- 
ing of  the  general  anatomy  of  the  Entozoa. 

The  Class  Calelmintha  contains  several 
species  of  Entozoa  which  are  obnoxious  to 
man  ;  of  these  may  be  first  mentioned  the 
Medina  or  Guinea-worm  ( Filaria  Medinensis, 
Gmel.)  This  species  is  developed  in  the  sub- 
cutaneous cellular  texture,  generally  in  the 
lower  extremities,  especially  the  feet,  sometimes 
in  the  scrotum,  and  also,  but  very  rarely,  be- 


Fig.  67.  neath  the  tunica  conjunctiva 
of  the  eye.  It  appears  to  be 
endemic  in  the  tropical  regions 
of  Asia  and  Africa. 

The  length  of  this  worm 
varies  from  six  inches,  to  two, 
eight,  or  twelve  feet;  its  thick- 
ness from  half  to  two-thirds 
of  a  line ;  it  is  of  a  whitish 
colour  in  general,  but  some- 
times of  a  dark  brown  hue. 
The  body  is  round  and  sub- 
equal,  a  little  attenuated  to- 
wards the  anterior  extremity. 
In  a  recent  specimen  of  small 
size,  we  have  observed  that  the 
orbicular  mouth  was  surround- 
ed by  three  slightly  raised 
swellings,  which  were  conti- 
nued a  little  way  along  the 
body  and  gradually  lost ;  the 
body  is  traversed  by  two  lon- 
gitudinal lines  corresponding 
to  the  intervals  of  the  two  well- 
marked  fasciculi  of  longitu- 
dinal muscular  fibres.  The 
caudal  extremity  of  the  male 
is  obtuse,  and  emits  a  single 
spiculum ;  in  the  female  it  is 
acute  and  suddenly  inflected. 

The  Filaria  Medinensis,  as 
has  just  been  observed,  is  oc- 
casionally located  in  the  close 
vicinity  of  the  organ  of  vision ; 
but  another  much  smaller  spe- 
cies of  the  same  Genus  of 
Nematoidea  infests  the  cavity 
of  the  eyeball  itself. 

The  Filaria  oculi  humani 
was  detected  by  Nordmann  in 
the  Liquor  Morgagni  of  the 
capsule  of  a  crystalline  lens  of 
a  man  who  had  undergone  the 
operation  of  extraction  for  ca- 
taract under  the  hands  of  the 
Baron  von  Grafe.  In  this  in- 
stance the  capsule  of  the  lens 
had  been  extracted  entire,  and 
upon  a  careful  examination 
half  an  hour  after  extraction 
there  wereobserved  in  the  fluid 
above-mentioned  two  minute 
and  delicate  Filaria  coiled  up 
in  the  form  of  a  ring.  One  of 
these  worms,  when  examined 
microscopically,  presented  a  rupture  in  the  mid- 
dle of  its  body,  probably  occasioned  by  the  ex- 
tracting needle,  from  which  rupture  the  intesti- 
nal canal  was  protruding ;  the  other  was  entire 
and  measured  three-fourths  of  a  line  in  length  ; 
it  presented  a  simple  mouth  without  any  appa- 
rent papillse,  (as  are  observed  to  characterize 
the  large  Filaria  which  infests  the  eye  of  the 
Horse,)  and  through  the  transparent  integument 
could  be  seen  a  straight  intestinal  canal,  sur- 
rounded by  convolutions  of  the  oviducts,  and 
terminating  at  an  incurved  anal  extremity. 

The  third  species  of  Filaria  enumerated 
among  the  Entozoa  Hominis  is  the  Filaria 


Filaria  Medinensis. 


ENTOZOA. 


123 


bronchialis  (jig.  68);  it  was  detected  by  Treut- 
ler*  in  the  enlarged 
Fig.  68.  bronchial  glands  of  a 

n       man:  the  length  of  this 
JST.      worm  is  about  an  inch  ; 
l/f        it  is  slender,  subatten- 
11  uated  anteriorly  (a), 

II  and  emitting  the  male 

j  j  spiculum  from  an  in- 

II  curved  obtuse  anal  ex- 

\\  tremity  (6). 

w.  The  next  Human 

\%         Entozoon  of  the  Ne- 
matoid  order  belongs 
\|i      to  the  genus  Tricho- 
]l      cephalus,  which,  like 
J  a       Filaria,  is  character- 
li       ized  by  an  orbicular 
M  mouth,  but  differs  from 

it  in  the  capillary  form 
^  of  the  anterior  part  of 

Filaria  bronchialis,       »he  h°p>  anf  in.  the 
magnified.  i°rm  of  the  sheath  or 

preputial  covering  of 
the  male  spiculum.  The  species  in  question, 
the  Tricocephalus  dispar,  Rud.  is  of  small  size, 
and  the  male  (*  fig.  69)  is  rather  less  than  the 
female.  It  occurs  most  commonly  in  the 
coecum  and  colon,  more  rarely  in  the  small 
intestines.  Occasionally  it  is  found  loose  in 
the  abdominal  cavity,  having  perforated  the 
coats  of  the  intestine.  The  capillary  portion 
of  this  species  makes  about  two-thirds  of  its 
entire  length  ;  it  is  transversely  striated,  and 
contains  a  simple  straight  intestinal  canal; 
the  head  (a)  is  acute,  with  a  small  simple 
terminal  mouth.  The  thick  part  of  the  body 
is  spirally  convoluted  on  the  same  plane,  and 
exhibits  more  plainly  the  dilated  moniliform 
intestine  (6) ;  it  terminates  in  an  obtuse  anal 
extremity,  from  the  inner  side  of  which  pro- 
ject the  intromittent  spiculum  and  its  sheath 
(c,  d).  The  corresponding  extremity  in  the 
female  exhibits  a  simple  foramen,  which,  like 
the  outlet  of  a  cloaca,  serves  the  office  of  both 
anus  and  vulva. 

With  respect  to  the  following  parasite  of  the 
Human  body,  the  Spiroptera  Hominis,  Rud., 
considerable  obscurity  prevails.    A  poor  wo- 
man, who  is  still  living  in  the  workhouse  of 
the  parish  of  St.  Sepulchre,  London,  has  been 
subject,  since  the  year  1806,  (when  she  was 
twenty-four  years  old,)  up  to  the  present  time, 
to  retention  of  urine,  accompanied  with  dis- 
tress and  pain  indicative  of  disease  of  the 
bladder.     The  catheter  has  been  employed 
from  time  to  time  during  this  long  period  to 
draw  off  the  urine,  and  its  application  has 
been,  and  continues  occasionally  to  be,  followed 
by  the  extraction  and  subsequent  discharge  of 
worms,  or  vermiform  substances,  with  nume- 
rous small  granular  bodies.    The  latter  are  of 
uniform  size,  resembling  small  grains  of  sand  : 
those  which  we  have  examined,  and  which  were 
preserved  in  spirit,  present  a  subglobular,  or 
irregularly  flattened  form ;  but  when  recently 

*  Opusc.  Patholog.  Anat.  p.  10,  tab.  ii.  fig.  3 — 
7.  Hamularia  Lymphaiica. 


Fig  69. 


Trichocepludus  dispar.    (*Natural  she. ) 


expelled,  I  am  assured  by  my  friend  Dr. 
Arthur  Farre,  that  they  are  perfectly  spherical ; 
they  consist  of  an  external  smooth,  firm,  dia- 
phanous coat,  including  a  compact  mass  of 
brown  and  minutely  granular  substance.  The 
inner  surface  of  the  containing  capsule  pre- 
sents, under  the  microscope,  a  regular,  beau- 
tiful, and  minute  reticulation,  produced  by 
depressions  or  cells  of  a  hexagonal  form. 
These,  therefore,  we  regard  as  ova,  and  not  as 
fortuitous  morbid  productions.*    The  vermi- 

*  "  Ovula  vero  sic  dicta  subglobosa  cum  arenulis 


124 


ENTOZOA. 


form  substances  are  elongated  bodies  of  a 
moderately  firm,  solid,  homogeneous  texture, 
varying  in  length  from  four  to  eight  inches ; 
attenuated  at  both  extremities;  having  the 
diameter  of  a  line  half-way  between  the  ex- 
tremities and  the  middle  part,  where  the  body 
is  contracted  and  abruptly  bent  upon  itself. 
Some  are  irregularly  trigonal,  others  tetragonal. 
In  the  three-sided  specimens  one  surface  is 
broad,  convex,  and  smooth ;  the  other  two  are 
narrow  and  concave,  and  separated  by  a  nar- 
row longitudinal  groove,  in  which  is  sometimes 
lodged  a  filamentary  brown  concretion.  In 
the  tetragonal  portions  the  broad  smooth  sur- 
face is  divided  into  two  parts  by  the  rising  of 
the  middle  part  of  the  convexity  into  an  angle. 
The  most  remarkable  appearance  in  these  am- 
biguous productions  is  the  beautiful  crenation 
of  one  of  the  angles  or  ridges  between  the 
convex  and  concave  facet;  which,  from  its 
regularity  and  constancy,  can  hardly  be  ac- 
counted for  on  the  theory  of  their  nature  and 
origin  suggested  by  Rudolphi :  '  lymphamque 
in  canalibus  fistulosis  coactam  passimque  com- 
pressam  filum  inrequale  efformare  crediderim.'* 
On  the  other  hand  it  is  equally  difficult  to  form 
any  satisfactory  notion  of  these  substances 
as  organized  bodies  growing  by  an  inherent 
and  independent  vitality.  We  have  not  been 
able  to  observe  a  single  example  in  vhich  the 
substance  had  both  extremities  well  defined 
and  unbroken ;  these,  on  the  contrary,  are 
flattened,  membranous,  and  more  or  less  jagged 
and  irregular.  They  present  no  trace  of  ali- 
mentary or  generative  orifices  on  any  part  of 
their  exterior  surface,  nor  any  canals  subser- 
vient to  those  functions,  in  the  interior  paren- 

Fig.  70. 


Spiroptera  hominis.  (*  Natural  sixe.) 

per  catheterem  ex  vesica  pauperculs  educta,  ne- 
quaquam  talia  habenda  sunt.  Corpuscula  sunt 
plus  minus  globosa,  tertiam  lineae  partem  diametro 
superantia,  duriuscula,  forcipi  comprimenti  reni- 
tentia,  dissecta  solida  visa,  quominus  pro  hydalulis 
haberi  possint,  quales  pritno  suspicatus  sum.  Con- 
crcmenta;  sunt  lymphatica  in  vesica  imorbosa  ex 
humoribus  alienatis  ibidem  secretis,  simili  forsan 
inodo  acarenula;  ex  lolio  pra;cipitata." — Rudolphi, 
Synops.  Entoz.  p.  251. 
*  Ibid.  p.  252. 


chyma.  If  subsequent  observations  on  re- 
cently expelled  specimens  of  these  most 
curious  and  interesting  productions  should, 
however,  establish  their  claims  to  be  regarded 
as  Entozoa,  they  will  probably  rank  as  a  sim- 
ple form  of  Sterelmint/ia.* 

The  existence  of  the  Spiroptera  Hominis  is 
founded  on  the  observation  of  substances  very 
different  from  the  preceding  productions.  The 
specimens  so  called  were  transmitted  to  Ru- 
dolphi, in  a  separate  phial,  at  the  same  time 
with  the  ova  and  larger  parenchymatous  bodies 
above  described,  and  are  presumed  to  have 
been  expelled  from  the  same  female  under  the 
same  circumstances.  They  consisted  of  six 
small  Nematoid  worms  of  different  sexes ; 
the  males  (fig.  70*)  were  eight,  the  females  ten 
lines  in  length,  slender,  white,  highly  elastic. 

The  head  (</,  fig.  70)  truncated,  and  with 
one  or  two  papillaa ;  the  mouth  orbicular,  the 
body  attenuated  at  both  extremities,  but  espe- 
cially anteriorly.  The  tail  in  the  female 
thicker,  and  with  a  short  obtuse  apex;  that  of 
the  male  more  slender,  and  emitting  a  small 
mesial  tubulus  (c),  probably  the  sheath  of  the 
penis :  a  dermal  aliform  production  near  the 
same  extremity  determines  the  reference  of  this 
Entozoon  to  the  genus  Spiroptera. 

There  are  no  specimens  of  this  Entozoon 
among  the  substances  discharged  from  the 
urethra  of  the  female,  whose  case  is  above 
alluded  to,  which  are  preserved  in  the  Museum 
of  the  College  of  Surgeons. 

The  following  parasite  of  the  urinary  appar 
ratus,  concerning  which  no  obscurity  or  doubt 
prevails,  is  the  Strongylus  gigas  (fig.  71),  the 
giant  not  only  of  its  genus  but  of  the  whole 
class  of  cavitary  worms.  This  species  is  de- 
veloped in  the  parenchyma  of  the  kidney 
itself,  and  occasionally  attains  the  length  of 
three  feet,  with  a  diameter  of  half  an  inch. 
A  worm  of  nearly  this  magnitude,  which  oc- 
cupied the  entire  capsule  of  the  left  kidney, 
of  the  parenchyma  of  which  it  had  occasioned 
the  total  destruction,  is  preserved  in  the.  collec- 
tion of  the  Royal  College  of  Surgeons. 

The  male  Strongylus  gigas  is  less  than  the 
female,  and  is  slightly  attenuated  at  both  ex- 
tremities. The  head  («)  is  obtuse,  the  mouth 
orbicular,  and  surrounded  by  six  hemispherical 
papillae  (a);  the  body  is  slightly  impressed 
with  circular  striae,  and  with  two  longitudinal 
impressions  ;  the  tail  is  incurved  in  the  male, 
and  terminated  by  a  dilated  pouch  orbursa,  from 
the  base  of  which  the  single  intromittent  spi- 
culum  (6)  projects.  In  the  female  the  caudal 
extremity  is  less  attenuated  and  straighter, 
with  the  anus  (c)  a  little  below  the  apex :  the 
vulva  ( d,fig.  95)  is  situated  at  a  short  distance 
from  the  anterior  extremity. 

The  Strongylus  gigas  is  not  confined  to  the 
Human  Subject,  but  more  frequently  infests 
the  kidney  of  the  Dog,  Wolf,  Otter,  Raccoon, 
Glutton,  Horse,  and  Bull.  It  is  generally  of 
a  dark  blood-colour,  which  seems  to  be  owing 

*  These  bodies  are  figured  in  the  excellent  ac- 
count of  the  present  anomalous  case  by  Mr.  Law- 
rence, in  the  Medico  -  Chirurgical  Transactions, 
vol.  ii.  pi.  8,  p.  385. 


ENTOZOA. 


125 


Fig.  71. 


Strongylus  gigas,  male. 

to  the  nature  of  its  food,  which  is  derived  from 
the  vessels  of  the  kidney,  as,  where  suppuration 
has  taken  place  around  it,  the  worm  has  been 
found  of  a  whitish  hue. 

The  Round-worm  ( Ascaris  Lumbricoides, 
Linn.)  (Jig.  72)  is  the  first  described*  and 
most  common  of  the  Human  Entozoa,  and 
is  that  which  has  been  subjected  to  the  most 
repeated,  minute,  and  successful  anatomical 
examinations.  It  is  found  in  the  intestines  of 
Man,  the  Hog,  and  the  Ox.  In  the  Human 
subject  the  round  worms  are  much  more  com- 
mon in  children  than  in  adults,  and  are  ex- 
tremely rare  in  aged  persons.  They  are  most 
obnoxious  to  individuals  of  the  lymphatic  tem- 
perament, and  such  as  use  gross  and  indi- 
gestible food,  or  who  inhabit  low  and  damp 

*  It  is  the  gX/uiv;  errpoyyuXoc  of  Hippocrates. 


Fig.  72.    localities.    They  generally  occur 
a        in  the  small  intestines. 

The  body  is  round,  elastic,  with 
a  smooth  shining  surface,  of  a 
whitish  or  yellowish  colour ;  atte- 
nuated towards  both  extremities, 
but  chiefly  towards  the  anterior 
one  ( a, fig.  72),  which  commences 
abruptly  by  three  tubercles  which 
surround  the  mouth,  and  charac- 
terize the  genus.  The  posterior 
extremity  (b)  terminates  in  an  ob- 
tuse point,  at  the  apex  of  which  a 
small  black  point  may  frequently 
be  observed.  In  the  female  this 
extremity  is  straighter  and  thicker 
than  in  the  male,  in  which  it  is 
terminated  more  acutely,  and  is 
abruptly  curved  towards  the  ventral 
side  of  the  body.  The  anus  is 
situated  in  both  sexes  close  to  the 
extremity  of  the  tail,  in  form  like 
a  transverse  fissure.  In  the  female 
the  body  generally  presents  a  con- 
striction at  the  junction  of  the  an- 
terior with  the  middle  third  (c)  in 
which  the  vulva  (d)  is  situated. 

The  body  of  the  Ascaris  lumbri- 
coides is  transversely  furrowed  with 
numerous  very  fine  stria,  and  is 
marked  with  four  longitudinal  equi- 
distant lines  extending  from  the 
head  to  the  tail.  These  lines  are 
independent  of  the  exterior  enve- 
lope, which  simply  covers  them ; 
two  are  lateral,  and  are  larger  than 
the  others,  which  are  dorsal  and 
ventral.  The  lateral  lines  com- 
mence on  each  side  the  mouth, 
but,  from  their  extreme  fineness, 
can  with  difficulty  be  perceived ; 
they  slightly  enlarge  as  they  pass 
downwards  to  about  one-third  of 
a  line  in  diameter  in  large  speci- 
mens, and  then  gradually  diminish 
to  the  sides  of  the  caudal  extremi- 
ty. They  are  occasionally  of  a  red 
colour,  and  denote  the  situation  of 
the  principal  vessels  of  the  body. 
The  dorsal  and  abdominal  longitu- 
dinal lines  (e,  fig.  72)  are  less 
marked  than  the  preceding,  and 
by  no  means  widen  in  the  same 
proportion  at  the  middle  of  the 
body.  They  correspond  to  the  two 
nervous  chords,  hereafter  to  be 
described. 

The  last  species  of  Human  En- 
tozoon  which  remains  to  be  noticed 
is  the  Ascaris  vermicularis  (fig.  73), 
a  small  worm,  also  noticed  by  Hip- 
pocrates under  the  name  of  xa-nct^g, 
and  claiming  the  attention  of  all  phy- 
sicians since  his  time,  as  one  of  the 
most  troublesome  parasites  of  chil- 
dren, and  occasionally  of  adults; 
in  both  of  whom  it  infests  the  larger 
intestines,  especially  the  rectum. 

The  size  of  the  Ascaris  vermicularis  varies 


126 


ENTOZOA. 


according  to  the  sex ;  the  males  rarely  equal 
two  lines  in  length  ;  the  females  attain  to  five 
lines  (*fig.  73.)    They  are  proportionally  slen- 
der, white,  and  highly  elastic.  The 
Fig.  73.    head  is  obtuse,  and  presents,  ac- 
H«     cording  to  the  repeated  observa- 
-a-    Hm     t'ons  °f  tne  experienced  Rudolphi, 
the  three  valvular  papillae  charac- 
teristic of  the  genus  Ascaris ;  but 
other  Helminthologists,  who  have 
failed  in  detecting  this  organization, 
refer  the  species   to  the  genus 
Oxyuris.    Besides  the  papillae  the 
head  presents  a  lateral,  semi-obo- 
vate  membrane  on  each  side,  the 
broader  end  being  anterior.  The 
body  soon  begins  to  grow  smaller, 
and  gradually  diminishes  to  a  su- 
bulate straight  extremity  in  the 
female.    In  the  male  the  posterior 
extremity  is  thicker,  and  is  spirally 
inflected  and  terminates  obtusely ; 
the  head  is  narrower  than  in  the 
female. 

In  the  following  tabular  arrange- 
ment of  the  internal  parasites  of 
the  Human  body,  they  are  disposed 
miculm-  Ver'  'n       c'asses  to  wn'cn  they  appear 
7*NatZal  resPectively  to  belong  according  to 
sixe 

0f     their  organization. 
female.) 

ENTOZOA  HOMINIS. 

Classis  Psychodiaria,  Bory  St.  Vincent. 

1.  Acephalocystis  endogena,  cui  locus 

Hepar,  cavum  Abdominis,  &c. 

2.  Echinococcus  Hominis,  Hepar,  Lien, 

Omentum. 
Classis  Polygastrica,  Ehrenberg. 

3.  Animalcula  Echinococci,  Hepar,  &c. 

in  Echinococco  abdita.* 
Classis  Protelmintha. 

4.  Cercaria  Seminis,  Semen  virile. 

5.  Trichina  spiralis,  Musculi  voluntarii. 
Classis  Sterelmintha. 

6.  Cysticercus  cellulosa,  Musculi,  Cere- 

brum, Oculus. 

7.  Taenia  Solium,  Intestina  tenuia. 

8.  Botkriocepalus  latus,  Intestina  tenuia. 

9.  Poly  stoma  Pinguicola,  Ovaria. 

10.  Distoma  hepaticum,  Vesica  fellea. 
Classis  Ccelelmintha. 

11.  Filaria  Medinensis,  Contextus  cellu- 

losus. 

12.  Filaria  oculi,  Cavum  Oculi. 

13.  Filaria  bronchialis,  Glandular  bron- 

chiales. 

14.  Tricocephalus  dispar,  Coecum,  Intes- 

tina crassa. 

15.  Spiroptera  hominis,  Vesica  urinaria. 

16.  Strongylus  gigas,  Ren. 

17.  Ascaris  lumbricoides,  Intestina  tenuia. 

18.  Ascaris  vermicularis,  Intestinum  rec- 

tum. 

Anatomy  of  the  Entozoa. 
Tegumentary  System. — There  are  few  spe- 

*  These  may  be  considered  rather  as  the  Para- 
sites of  the  Echinococcus  than  of  the  human  sub- 
ject. 


cies  of  the  Sterelmintha  in  which  a  distinct 
external  tegumentary  covering  can  be  demon- 
strated. In  the  Cystic,  Cestoid,  and  most  of 
the  Trematode  worms,  the  parenchymatous 
substance  of  the  body  is  simply  condensed  at 
the  surface  into  a  smooth  and  polished  conum 
of  a  whitish  colour,  without  any  development 
of  pigmental  or  cuticular  layers.  The  various 
wrinkles  and  irregularities,  which  the  super- 
ficies of  these  Entozoa  frequently  presents, 
result  from  the  action  of  the  contractile  tissue 
of  the  corium  :  this  substance,  in  the  larger 
Taniee,  begins  to  assume  a  fibrous  disposition, 
and  tears  most  readily  in  the  longitudinal  di- 
rection ;  it  can  be  more  distinctly  demonstrated 
as  a  muscular  structure  in  the  larger  species 
of  Trematoda.  By  maceration  in  warm  water 
the  rugae  of  the  integument  disappear ;  the 
smooth  external  surface,  so  well  adapted  to 
glide  over  the  irregularities  of  a  mucous  mem- 
brane, is  then  distinctly  demonstrated;  and, 
when  magnified,  an  infinite  number  of  minute 
pores,  variously  disposed,  are  seen  perforating 
the  whole  surface,  especially  in  the  Acantho- 
cephalous  worms.  It  is  these  pores  which,  in 
the  dead  worm  at  least,  allow  a  ready  passage 
to  the  surrounding  fluid  into  the  interstices  of 
the  parenchyma,  where  it  sometimes  accumu- 
lates so  as  to  swell  out  the  body  to  three  or 
four  times  its  previous  bulk ;  and  it  may  be 
readily  supposed,  therefore,  that  the  skin  here 
performs  some  share  in  the  nutrient  functions, 
by  absorbing  a  proportion  of  the  mucous  or 
serous  secretions  in  which  the  Entozoa  are 
habitually  bathed. 

In  the  Acanthocephala  the  skin,  which  is 
but  little  extensible  and  friable,  is  united  to 
the  subjacent  muscular  fibres  by  means  of  a 
whitish  spongy  tissue  which  adheres  to  it  most 
strongly  opposite  the  dorsal  and  ventral  longi- 
tudinal lines  or  canals.  As,  however,  the  skin 
is  with  difficulty  changed  by  maceration,  while 
the  parts  which  it  surrounds  soon  go  into 
putrefaction,  it  can  thus  be  easily  separated 
and  demonstrated  as  a  distinct  substance.  It 
presents  no  definite  fibrous  structure  under  the 
microscope,  and  tears  with  equal  facility  in 
every  direction. 

In  a  large  Trematode  worm,  the  Distoma 
clavatum,  Rud.,  which  infests  the  intestines 
of  the  Albicore  and  Bonito,  the  body  is  pro- 
tected by  a  crisp  sub-diaphanous  cuticle,  re- 
sembling in  its  structure  and  properties  that  of 
the  Echinorhynchus. 

A  similar  covering  may  be  demonstrated 
very  readily  in  the  genus  Linguatula,  among 
the  Calelminiha,  and  can  be  separated,  but 
with  more  difficulty,  from  the  subjacent  mus- 
cles in  the  Ascarides.  In  the  great  Round- 
worm ( Ascaris  lumbricoides )  the  integu- 
ment is  smooth  and  unctuous,  is  more  exten- 
sible in  the  longitudinal  than  the  transverse 
directions,  tears  with  an  unequal  rupture  like 
a  thin  layer  of  transparent  horn,  and  preserves 
its  transparency  in  solutions  of  corrosive  sub- 
limate, alum,  and  in  alcohol.  In  this  species, 
in  which  the  digestive  canal  is  completely  de- 
veloped, it  is  worthy  of  remark  that  the  mi- 
croscope does  not  demonstrate  pores  in  the 
cuticle,  as  in   the  external  covering  of  the 


ENTOZOA. 


127 


Echinorhynchus  and  other  gterelminthoid 
worms  ;  but  a  series  of  extremely  minute  close- 
set  parallel  transverse  lines  are  brought  into 
view,  which  are  permanent,  and  depend  on 
the  texture  of  the  epidermoid  substance  itself. 

Although  a  distinct  and  general  epidermic 
covering  cannot  be  demonstrated  in  the  more 
simple  Sterelmiutha,  the  soft  bodies  of  which 
entirely  dissolve  after  a  few  days'  maceration, 
and  which,  in  animals  examined  soon  after 
death,  are  often  found  in  consequence  to  have 
lost  their  natural  form,  and  to  have  degenerated 
into  a  kind  of  mucus,*  yet  in  most  species 
traces  of  the  epidermic  system  are  manifested 
in  some  limited  parts  of  the  body :  thus  it  ap- 
pears in  the  form  of  hard  transparent  horny 
hooklets  around  the  oral  proboscis  in  the  Cystic 
genera,  as  in  the  Cysticercus  cellulose  (fig.  61), 
and  most  of  the  Cestoid  worms.  In  the  Flori- 
^eps,  Cuv.,  these  recurved  spines  are  arranged 
along  the  margins  of  four  retractile  tentacles, 
which  thus  serve  to  fix  the  worm  to  the 
slippery  membranes  among  which  it  seeks  its 
subsistence.  In  the  Trematode  worms  epider- 
mic spines  are  seldom  developed  ;  the  species 
which  infests  the  human  subject  (Distotna 
hepaticum )  presents  no  trace  of  them.  When 
they  exist  in  this  order,  they  are  either  confined 
to  the  head,  or  are  at  the  same  time  spread  over 
a  greater  or  less  proportion  of  the  surface  of 
the  body.  Of  the  first  disposition  we  have  an 
example  in  the  Gryporhynchus  pusillus,  (a  tre- 
matode worm  infesting  the  intestines  of  the 
Tench,)  which  manifests  an  affinity  to  the 
Tenia  armatee  in  its  proboscis  armed  with  six- 
teen strong  recurved  spines  arranged  in  a 
double  circular  series.  In  the  Distoma  trigo- 
nocephalum  there  are  two  straight  spines  on 
each  side  of  the  head.  In  Distoma  armatum 
the  head  is  entirely  surrounded  by  similar 
straight  spines.  In  Distoma  ferox  the  head 
bears  a  circle  of  recurved  spines.  In  Distoma 
denticulatum  the  head  is  surrounded  by  a  series 
of  large  straight  spines,  and  there  is  a  series 
of  smaller  spines  around  the  neck.  In  Dis- 
toma spinulosa  the  anterior  part  of  the  body  is 
beset  with  reflected  spines ;  and  in  the  Dis- 
toma perlatum,  Nord.,  the  whole  surface  of  the 
body  is   armed  with  hooklets,  arranged  in 


Proboscis  of  Echinorhynchus  gigus,  magnified. 
*  Rudolphi,  Hist.  Entoz.  i.  p.  230. 


transverse  rows,  eaGh  being  supported  on  a 
cutaneous  prominence  and  bent  backwards, 
(see  Jig.  91).  ' 

For  a  description  of  the  complicated  horny 
and  cartilaginous  parts  of  the  dermo-skeleton, 
which  enter  into  the  mechanism  of  the  suckers 
of  the  worms  belonging  to  the  genera  Diplo- 
zoon  and  Octobothrium,  we  are  compelled  from 
want  of  space  to  refer  the  reader  to  Nordmann's 
Mikrographische  Bettrage,  ( Erstes  Heft.) 

In  the  Acanthocephala  the  head,  as  the  name 
implies,  is  armed  with  recurved  spines  or 
hooks,  which  are  arranged  in  quincunx  order 
around  a  retractile  proboscis,  {jig- 74);  and, 
in  addition  to  these,  some  species  have  smaller 
and  less  curved  spines  dispersed  over  the  neck 
or  body. 

Among  the  Calelmintha  the  genus  Lingua- 
tula  is  remarkable  for  the  development  of  four 
large  reflected  spines,  arranged  two  on  each 
side  the  central  mouth ;  and  which  can  be  par- 
tially retracted  within  depressions  of  an  elon- 
gated semilunar  figure.  The  worm  attaches 
itself  so  firmly  by  means  of  the  horny  hooks 
that  it  will  suffer  its  head  to  be  torn  from  its 
body  rather  than  quit  its  hold  when  an  attempt 
is  made  to  remove  it  while  alive.  In  the 
Trichocephalus  uncinatus  the  truncated  head 
presents  at  its  anterior  margin  a  series  of  hard 
reflected  hooks  continued  directly  from  the 
integument.  In  the  Strongylus  armatus,  which 
has  sometimes  a  singular  nidus  in  the  me- 
senteric arteries  of  the  Horse  and  Ass,  the 
globose  head  is  terminated  anteriorly  by  straight 
spines,  but  in  the  Strongylus  dentatus  with 
hooklets.  Lastly,  we  may  notice  the  very 
singular  worm  found  by  Rudolphi  in  the 
oesophagus  of  the  Water-hen,  and  which  he  calls 
the  Strongylus  horridus,  where  the  body  presents 
four  longitudinal  rows  of  reflected  hooklets. 

The  epidermic  processes,  when  thus  traced 
through  the  different  orders  of  Entozoa,  pre- 
sent but  few  modifications  of  form,  and 
have  little  variety  of  function ;  the  straight 
spines  at  the  mouth  serve  to  irritate  and  in- 
crease the  secretion  of  the  membrane  or  cyst 
with  which  the  worm  is  in  contact;  the  re- 
curved hooklets  serve  as  prehensile  instru- 
ments to  retain  the  proboscis  and  the  worm 
in  its  position ;  and  when  they  are  spread 
over  the  surface  of  the  body,  they  may  have 
the  additional  function  of  aiding  in  the  loco- 
motion of  the  species,  analogous  to  the  spines 
which  arm  the  segments  of  the  (Estrus,  which 
passes  its  larva  state,  like  an  Entozoon,  in  the 
interior  of  the  stomach  and  intestines  of  a 
higher  organized  animal. 

Muscular  system. — Although  in  every  order 
both  of  the  Parenchymatous  and  Cavitary 
worms,  living  specimens  have  been  observed 
to  exhibit  sufficiently  conspicuous  motions,  yet 
the  muscular  fibre  is  not  always  distinctly  eli- 
minated in  them.  In  the  Cysticerci,  however, 
liudolphi  describes  two  bundles  of  fibres  as 
arising  from  the  inferior  part  of  the  body,  and 
expanding  upon  the  upper  part  of  the  cyst. 
We  have  traced  corresponding  fibres  extending 
to  the  head  in  a  large  Cysticercus  tenuicollis; 
which  fibres  were  doubtless  the  principal  agents 


128 


ENTOZOA. 


in  retracting  the  head  within  the  terminal  cyst; 
and  this  part,  in  the  same  specimen  also,  pre- 
sented a  remarkably  distinct  series  of  transverse 
stria?,  indicating  most  probably  the  circular 
fibres  which  contract  the  cyst  in  the  transverse 
direction,  and  protrude  the  proboscis.*  This 
species  of  Hydatid,  which  is  common  in  the 
abdomen  of  Sheep,  where  it  is  either  sus- 
pended in  a  cyst  to  the  mesentery  or  omen- 
tum, or  embedded  in  the  liver,  &c.  has  been 
the  subject  of  numerous  observations,  and  is 
generally  selected  to  demonstrate  the  muscular 
phenomena  in  an  animal  of  very  simple  orga- 
nization. When  extracted  from  a  recently 
killed  sheep,  and  placed  in  water  at  the  blood- 
heat,  the  cyst  may  then  be  observed  to  become 
elongated,  and  agitated  with  undulatory  move- 
ments ;  the  retracted  part  of  the  body  is  thrust 
forth,  and  again,  perhaps,  drawn  in  ;  during 
the  latter  action  the  anterior  part  of  the  cyst 
becomes  wrinkled  and  is  drawn  back,  gliding 
into  the  posterior  part  of  the  cyst;  the  anterior 
part  of  the  body  is  at  the  same  time  retracted, 
and  is  received  into  the  posterior ;  and  thus  by 
degrees  the  head  and  all  the  body  become 
concealed  in  the  terminal  cyst. 

In  the  Cestoidea  the  muscular  structure  is 
indicated  slightly  by  impressions  on  the  sur- 
face of  the  body,  but  it  is  seldom  that  a  distinct 
layer  of  muscular  fibres  can  be  demonstrated. 

To  the  worms  of  the  genus  Caryophylleus 
both  Zeder  and  Rudolphi  agree  in  ascribing 
longitudinal   fibres,  which  extend  along  the 
anterior   part  of    the    body  and  transverse 
fibres,  which  are  conspicuous  in  the  pos- 
terior  segments.    In  the  Tania  both  trans- 
verse and  longitudinal  strata  of  fibrils  are  stated 
to  exist,f  obscure  indeed,  or  almost  impercep- 
tible in  the  smaller  species ;  but  more  evident 
in  the  larger  specimens,  in  which,  according  to 
Iludolphi,  each  segment  has  in  general  its  own 
strata,  whence  it  enjoys,  for  some  time  after 
being  separated  from  the  rest  of  the  body, 
distinct  and  peculiar  motions;  and  such  joints 
have  been  described  as  distinct  species  of  En- 
tozoa,  under  the  name  of  Cucur- 
Fig.  75.    bitina.     In  the  Bot/iriocepfialus 
fiai     lutus,  on  the  other  hand,  the  lon- 
/  r"@fl      g'tudinal  fibres  are  continued  from 
m  IBB     one  joint  to  another,  whence  the 
V  ifflB      segments  are  less  readily  separable, 
|jBpP      and  a  common  and  continuous  co- 
liSro       vering  may  be  dissected  from  off 
pl^Si      the  body  of  this  species. 
tpS3%        Living  Taeniae  placed  in  warm 
water  exhibit  undulatory  motions. 
fSraffj     The  body  of  one  of  these  worms  is 
fesmf     sometimes  found  to  be  tied  at  some 
fjWi\       part  in  a  complicated  knot,  as  seen 
w^^iL     in  Jig.  75,  doubtless  by  means  of 
v  .vvl  R>£  mese  m°tions.   The  Tcenia  solium, 
l'Ei  I     when  recently  expelled  from  the 
Ttenia      body  by  the  irritation  of  a  vermifuge 
solium.      remedy,  is  occasionally  contracted 
to  the  length  of  a  few  inches,  the 

*  See  Preparation,  No.  409  A,  Physiological 
Series  Mus.  Roy.  Coll.  of  Surg.  Catalogue,  vol.  i, 
p.  115. 

f  Rudolphi,  Hist.  Entoz.  i.  p.  223. 


segments  appearing  as  close-set  transverse  stria; ; 
when  placed  in  water,  after  a  few  hours  it  will 
have  returned  to  a  length  of  as  many  feet. 
Werner*  relates  an  instance  of  a  Taenia  which 
extended  from  the  anus  of  a  patient  to  the 
length  of  three  feet,  and  which  returned  itself 
almost  wholly  into  the  intestine,  the  dependent 
part  being  drawn  upwards  by  the  superior. 
Other  and  still  more  extraordinary  instances  of 
the  movements  of  the  Cestoid  worms  are  on  re- 
cord ;  but  that  the  separated  joints  of  the  Tania 
solium  should  be  able  to  creep  several  feet  up  a 
perpendicular  wall  could  scarcely  gain  a  mo- 
ment's credit,  if  the  fact  were  not  related  by 
no  less  distinguished  a  naturalist  than  Pallas.t 

In  general  the  muscular  fibres  cannot  be 
observed  in  the  diaphanous  bodies  of  the 
smaller  Trernatoda,  yet  every  part  is  endowed 
with  active  contractility:  in  the  larger  species, 
however,  both  longitudinal  and  transverse  strata 
of  fibres  may  be  demonstrated  in  the  tegumen- 
tary  muscular  covering  of  the  body ;  both  which 
we  have  distinctly  seen  in  the  large  Distoma 
clavatum.  The  muscular  fibres  of  the  aceta- 
bula  are  disposed  in  two  series,  one  radiating 
from  the  centre  to  the  circumference,  the  other 
in  concentric  circles.  The  muscular  tissue  is 
also  well  developed  around  the  base  of  the 
sucker,  by  which  the  animal  is  enabled  to  pro- 
trude them  from  the  surface. 

In  the  Planaria,  in  which,  as  in  the  Tania, 
according  to  our  observations,  the  muscular 
system  is  indicated  only  by  striae  on  the  super- 
ficies of  the  apparently  homogeneous  paren- 
chyma, the  phenomena  of  muscularity  are 
strikingly  displayed  in  the  varied  and  energetic 
actions  of  the  living  animal.  They  lengthen, 
shorten,  widen,  contract,  or  contort  the  body  in 
various  degrees  and  directions  :  their  mode  of 
locomotion  on  a  solid  plane  is  by  an  insen- 
sible undulation,  or  successive  approximation 
of  small  proportions  of  the  body,  producing 
a  gliding  movement,  as  in  the  Slug;  and  the 
same  actions  take  place  in  swimming  through 
the  water,  except  that  the  body  is  reversed ; 
and  the  ventral  surface  turned  upwards,  as  in 
the  Carinaria  and  other  aquatic  Gastropods. 
When  seizing  a  living  prey,  as  in  fig.  76,  the 
contractions  of  the  body 
Fig.  76.  are  more  vigorous  and 


In  the  Fkhinorhynchus 
the  muscular  fibres  are 
of  a  whitish  colour,  semi- 
transparent,  and  of  a  ge- 
latinous appearance;  they 


Planaria  lactea  (B),    aie  eminently  contractile, 
feeding  on  a  Nais.       and  readily  respond  to 
the  application  of  both 
chemical  and  pbysical  stimuli.    Cloquet  ob- 
served them  to  contract  under  the  influence  of 
the  galvanic  current  six  hours  after  the  cessation 

*  As  quoted  by  Rudolphi.  *  Taenia  ad  trium 
ulnarum  longitudinem  ex  mulieris  ano  propen- 
dens,  in  casu  qnem  Wernerus  (1.  c.  47)  ret'ert, 
tota  fere  in  pristinum  hospitium  rediit,  pars  pro- 
pendens  itaque  a  superiore  sursum  ducta  :  similes 
omnino  casus  Andryus  habet.' — Ibid.  p.  223. 

t  Also  quoted  by  Rudolphi,  p.  223. 


ENTOZOA. 


129 


of  all  spontaneous  movement.  The  general 
muscles  of  the  body  are  disposed  in  two  layers, 
of  which  the  fibres  of  the  external  are  trans- 
verse, those  of  the  internal  longitudinal. 

With  respect  to  the  disposition  of  the  mus- 
cular system  of  the  Nematoid  worms,  a  dif- 
ference of  opinion  is  entertained  by  some  ex- 
perienced comparative  anatomists. 

Professor  De  Blainville*  describes,  in  the 
Ascaris  lumbricoides,  the  external  stratum  of 
muscular  fibres  as  being  longitudinal,  while 
the  internal,  he  observes,  are  evidently  trans- 
verse, and  much  more  numerous  at  the  an- 
terior than  the  posterior  part  of  the  body. 
M.  Cloquet,  on  the  contrary,  in  his  elaborate 
monograph  on  the  Ascaris  lumbricoides,  states 
that  the  exterior  layers  of  muscular  fibres  are 
transverse,  and  the  internal  longitudinal.  In 
a  large  specimen  of  the  Strongylus  gigus,  Rud., 
which  we  have  dissected  and  examined  micro- 
scopically for  the  muscular  system,  we  find 
that  a  very  thin  layer  of  transverse  fibres  ad- 
heres strongly  to  the  integument,  the  fibres 
being  imbedded  in  delicate  furrows  on  the 
internal  surface  of  the  skin  ;  within  this  layer, 
and  adhering  to  it,  but  less  firmly  than  the 
transverse  fibres  do  to  the  integument,  there 
is  a  thicker  layer  of  longitudinal  fasciculi, 
which  are  a  little  separated  from  one  another, 
and  distributed,  not  in  eight  distinct  series, 
but  pretty  equally  over  the  whole  internal 
circumference  of  the  body.  Each  fasciculus 
is  seen  under  a  high  magnifying  power  to  be 
composed  of  many  very  fine  fibres,  but  these 
do  not  present  the  transverse  striae  which  are 
visible  by  the  same  power  in  the  voluntary 
muscular  fibres  of  the  higher  animals.  The 
longitudinal  fibres  are  covered  with  a  soft 
tissue  composed  of  small  obtuse  processes, 
filled  with  a  pulpy  substance,  and  containing 
innumerable  pellucid  globules,  and  at  the  an- 
terior extremity  of  the  body  this  tissue  assumes 
a  disposition  as  of  transverse  fasciculi  ( fig.  79). 
In  the  Ascaris  lumbricoides  similar  internal 
transverse  bands  are  shown  in  Jig.  88,e,e,  and 
are  those  which  Professor  Blainville  regards 
as  muscular,  and  Cloquet  as  vascular  organs. 
We  cannot  detect  a  tubular  structure  in  these 
parts,  neither  have  they  the  texture  and  con- 
sistence of  the  true  fibrous  parts  :  they  are  soft 
pulpy  substances,  doubtless  connected  with 
the  nutritious  functions,  and  probably  the  or- 
gans of  absorption. 

Besides  the  general  muscular  investment  of 
the  body,  there  are  distinct  muscles  in  most 
of  the  Entozoa,  developed  for  the  movement 
of  particular  parts,  as  the  retractile  hooks  of  the 
Linguatula  and  Porocephalus,  and  the  probo- 
scides  of  the  Cestoid  and  Acanthocephalous 
worms.  Of  the  latter  organ  the  Lchinorhynchus 
gigas  offers  a  good  example.  The  proboscis  in 
this  species  (Jig.  77)  is  a  short,  firm,  elastic, 
cylindrical  tube,  buried  with  its  appropriate  mus- 
cles in  the  neck  of  the  animal,  as  in  a  sheath;  and 
having  its  anterior  extremity  (a,  b)  terminated 

*  Dictionnaire  des  Sciences  Naturelles,  torn.  iii. 
App.  p.  40. 

+  Anatomie  de  l'Ascaride  Lombricoide,  p.  17. 
VOL.  II. 


Fig.  77. 


Retracted  proboscis  and  its  muscles,  Echynorhynchus 
gigas.  Cloquet. 

by  a  spherical  eminence  armed  with  four  rows 
of  recurved  spines.  The  retractor  muscles  are 
four  in  number,  two  superior  and  two  inferior, 
(J\  g,)  flattened,  elongated,  and  of  a  triangular 
figure.  They  are  continuous  at  their  base  or 
posterior  extremity,  with  the  longitudinal  fibres 
of  the  body ;  their  anterior  extremity,  which 
is  extremely  delicate,  is  inserted  into  the  poste- 
rior part  of  the  proboscis.  The  protractile  mus- 
cles (c,  d)  are  also  four  in  number,  short  but 
strong,  and  forming,  as  it  were,  a  sheath  to  the 
proboscis  ;  they  are  attached  to  the  anterior 
part  of  the  tegumentary  sheath,  and  pass  back- 
wards to  be  inserted  into  the  posterior  extremity 
of  the  proboscis  in  the  intervals  left  by  the 
retractor  muscles.  The  motions  of  the  pro- 
boscis thus  liberally  supplied,  are,  as  might  be 
expected,  more  lively  than  those  exhibited  by 
any  other  part  of  the  body.  When  it  is  drawn 
back  into  its  sheath  by  means  of  the  retractor 
muscles,  the  hooklets  seem  to  be  drawn  close 
to  the  side  of  the  bulbous  extremity,  whence 
we  may  infer  that  these  also  have  their  appro- 
priate muscles. 

Nervous  system.  —  The  Entozoa  in  which 
the  nerves  can  be  most  easily  and  distinctly 
demonstrated,  are  the  Linguatula  tanioides 
and  the  larger  species  of  the  Nematoidea, 
especially  the  Strongylus  gigas. 

In  the  Linguatula  a  proportionally  large 
ganglion  (g,  Jig.  78)  is  situated  immediately 
behind  the  mouth,  and  below  the  oesophagus, 
which  is  turned  forward  in  the  figure,  at  o; 
small  nerves  (h,  i,  k)  radiate  from  this  centre  to 
supply  the  muscular  apparatus  of  the  mouth 
and  contiguous  prehensile  hooklets ;  and  two 
large  chords  (7, 1)  pass  backwards  and  extend 
along  the  sides  of  the  abdominal  aspect  of  the 
body  to  near  the  posterior  extremity,  where 

K 


130 


ENTOZOA. 


E'4 


78.  ihey  gradually  become 

-  expanded  and  blended 

;*  with  the  muscular  tissue. 

I®  _  In    the  Strongylus 

gigas,  a  slender  nervous 
ring  (a,  a,  Jig.  79)  sur- 
rounds the  beginning  of 
the  gullet,  and  a  single 
chord  is  continued  from 
its  inferior  part  and  ex- 
tends in  a  straight  line 
along  the  middle  of  the 
ventral  aspect  (c,  d)  to  the 
opposite  extremity  of  the 
body,  where  a  slight 
swelling  is  formed  im- 
mediately anterior  to  the 
anus,  which  is  surround- 
ed by  a  loop  (e)  analo- 
gous to  that  with  which 
the  nervous  chord  com- 
menced. The  abdominal 
nerve  is  situated  internal 
to  the  longitudinal  mus- 
cular fibres,  and  is  easily 
distinguishablefromthem 
with  the  naked  eye  by 
its  whiter  colour,  and  the 
slender  branches  (b,  b) 
which  it  sends  off  on  each 
side.  These  transverse 
twigs  are  given  off  at 
pretty  regular  intervals  of 
about  half  a  line,  and 
may  be  traced  round  to 
nearly  the  opposite  side 
of  the  body.  The  entire 
nervous  chord  in  the  fe- 
male of  thisspecies  passes 
to  the  left  side  of  the 
vulva,  and  does  not  di- 
vide to  give  passage  to 
the  termination  of  the 
vagina,  as  Cloquet  de- 
scribes the  corresponding 
ventral  chord  to  do  in 
the  Ascaris  Lutnbricoides. 
In  the  latter  species,  and 
most  other  Nematoidea,  a  dorsal  nervous  chord 
is  continued  from  the  oesophageal  ring  down  the 
middle  line  of  that  aspect  of  the  body  corres- 
ponding to  the  ventral  chord  on  the  opposite 
aspect;  but  we  have  not  found  the  dorsal  chord 
in  the  Strongylus  gigas.  The  nervous  system 
in  the  latter  Entozoon  obviously  therefore  ap- 
proximates to  that  of  the  Anellides;  but  it  differs 
in  the  absence  of  the  ganglions,  which  in  all 
the  red-blooded  worms  unite  at  regular  inter- 
vals two  lateral  nervous  columns  ;  it  resembles 
on  the  other  hand  most  closely  the  simple  and 
single  ventral  chord  in  the  Sipunculus. 

Living  Ascarides  are  sensible  to  different 
mechanical  stimuli  applied  to  the  surface  of 
the  body,  and  the  sudden  and  convulsive 
movements  which  take  place  when  alcohol, 
vinegar,  or  alum-solution  are  applied  to  the 
mouth,  would  seem  to  imply  that  they  possess 
a  sense  of  taste:  tor  light,  noise,  or  odour  they 


111 


Nervous  system  and  fe- 
male organs  of  genera- 
tion of  Linguatula  tce- 
nioides,  magnified. 


mm 


mm 

Commencement  and  termina- 
tion of  the  nervous  system, 
Strongylus  gigas,  magnified. 


Fig.  79.  are,  as  might  be  ex- 

pected from  the 
sphere  of  their  ex- 
istence, totally  in- 
sensible. 

In  those  Entozoa 
which  infest  the  parts 
of  an  animal  body, 
where  they  may  be 
exposed  to  the  influ- 
ence of  light,  as  the 
gills  of  fishes,  we 
should  not  be  un- 
prepared to  meet 
with  coloured  eye- 
specks,  or  such  sim- 
ple forms  of  the  or- 
gan of  vision  as  oc- 
cur in  Infusoria  and 
other  invertebrate 
animals  of  a  low 
grade  of  organiza- 
tion. Nordmann  de- 
tected four  small 
round  ocelli,  of  a 
dark-brown  colour, 
in  the  Gyrodactylusauriculatus,  a  Cestoid  worm, 
found  in  the  branchial  mucus  of  the  Bream 
and  Carp  ;  the  eye-specks  are  situated  a  little 
way  behind  the  head,  and  yield  on  pressure  a 
blackish  pigment.  V.  Baer  observed  two 
small  blackish  ocelli  behind  the  orifice  of  the 
mouth  in  the  Polystomum  Integerrimum,  a 
Trematode  species,  which  infests  the  urinary 
or  allantoid  bladder  of  the  Frog  and  Toad. 
Now  this  large  receptacle  is  well  known  to 
contain  almost  pure  water ;  and  as  the  Poly- 
stomum is  very  closely  allied  to  the  Planaria, 
which  habitually  live  in  fresh  water,  it  is  pro- 
bable that  the  allantoid  bladder  may  be  only 
its  occasional  and  accidental  habitation.  With 
respect  to  the  Planaria  these  are  almost  univer- 
sally provided  with  eye-specks,  varying  in  num- 
ber from  two,  as  in  the  Planar ia  lactea,  (Jig. 
80,  A)  to  forty,  of  a  brown  or  black  colour,  the 
external  covering  of  which  is  tran- 
sparent and  corneous.  From  the 
experiments  of  M.  Duges*  on 
these  non-parasitic  Stere.lminthu, 
we  learn  that  when  the  solar  light 
is  directed  to  the  head,  they  escape 
from  its  influence  by  a  sudden  move- 
ment, and  they  also  give  unequi- 
vocal, though  less  energetic,  proofs 
of  their  subjection  to  the  influence 
of  diffused  and  artificial  light.  The 
temporary  ocelli  observed  in  the 
young  of  certain  species  of  Dis- 
toma\  will  be  presently  noticed. 

*  Annales  des  Sciences  Natnrelles,  1828,  p.  10. 

t  Conf.  also  Rudolphi,  Synops.  Entoz.  p.  442, 
where,  in  the  description  of  the  Scolex  polymor- 
phus,  a  Cestoid  worm  infesting  the  intestines  of 
Fish  and  Cephalopoda,  he  observes,  "  punctu  duo 
volo  corporis  albi  sanguinea,  sa?pe  lulgentia,  qualia 
nullis  in  Entozois  aliis  videre  Iicuit,  quaeque  in 
Gobii  minuti  Scolece  vasa  duo  rubra  parallela  pone 
caput  incipientia  et  retrorsum  ducta,  in  corpore 
autera  evanida,  effingere  observavi." 


ENTOZOA. 


131 


Digestive  organs. — We  have  already  alluded 
to  the  two  leading  modifications  of  the  ali- 
mentary canal,  on  which  the  binary  division 
of  the  Entozoa  of  Rudolphi  is  founded,  viz. 
into  Sterelmintha  or  those  in  which  the  nu- 
trient tubes,  without  anal  outlet,  are  simply 
excavated  in  the  general  parenchyma,  and  into 
the  Cazlelmintha,  in  which  an  intestinal  canal, 
with  proper  parietes,  floats  in  a  distinct  ab- 
dominal cavity,  and  has  a  separate  outlet  for 
the  excrements.  In  both  these  divisions  the 
mouth  is  variously  modified,  so  as  to  afford 
zoological  characters  for  the  subordinate 
groups ;  and  the  alimentary  canal  itself  in 
the  Sterelmintha  presents  several  important 
differences  of  structure. 

Cystica. — The  Cystic  worms  are  generally 
gifted,  as  in  the  species  ( Cysticercivs  cellulose ) 
which  occasionally  infests  the  human  subject, 
with  an  uncinated  proboscis  for  adhering  to  and 
irritating,  and  four  suctorious  mouths  for  ab- 
sorbing the  fluid  secreted  by,  the  adventitious 
cyst  in  which  they  are  lodged.  In  the  larger 
Cysticerci  lateral  canals  may  be  traced  from  the 
suctorious  pores  extending  down  the  body 
towards  the  terminal  cyst,  but  they  appear 
not  to  terminate  in  that  cavity,  the  fluid  of 
which  is  more  probably  the  result  of  secretion 
or  endosmosis.  We  cannot,  however,  partici- 
pate in  the  opinion  of  Rudolphi,*  that  the 
retracted  head  derives  nutriment  from  the 
surrounding  fluid  of  the  caudal  vesicle,  for  if 
that  were  the  case,  where  would  be  the  neces- 
sity for  an  armed  rostellum  in  addition  to 
the  absorbent  pores?  The  frequency  with 
which  the  Cysticerci  are  found  with  the  head 
so  retracted,  may  be  attributed  to  the  in- 
stinctive action  arising  from  the  stimulus  of 
diminished  temperature  and  other  changes 
in  the  surrounding  parts  occasioned  by  the 
death  of  the  animal  in  which  the  hydatid 
has  been  developed. 

Cestoidea. — In  the  Ccstoidea  the  digestive 
apparatus  commences  for  the  most  part  by  two 
or  four  oral  apertures,  to  which,  in  many  spe- 
cies (the  Tania  armata ),  a  central  uncinated 
proboscis  is  superadded,  as  in  the  Cysticerci. 
Sometimes  the  mouths  are  in  the  form  of  oblong 
pits  or  fossa?,  as  in  the  Botliriocephalus  lotus,  and 
the  allied  species  grouped  under  the  same  gene- 
ric name;  or  they  have  the  structure  of  circular 
suctorious  discs,  as  in  the  Tania  solium,  and 
othertrue  Tania.f  In  both  genera  two  alimen- 
tary canals  are  continued  backwards  in  a  straight 
line  near  the  lateral  margins  of  the  body  (e,  e, 

.  "  Osculis  lamen  canalihusque  dictis  omnem 
aquae  vim  vesica  caudali  collectam  parari  potuisse 
vix  credibile,  sed  hac  parata  vermem  eandem 
absorbere  ideoque  semper  fere  caput  liuic  immissum 
offerre,  longe  aliam  vero  fluidi  advehendi  viam 
dari,  plurima  suadent."—  Hist.  Entoz.  i.  p.  279. 

t  Many  beautiful  preparations,  showing  the 
nutrient  canals  of  the  Tania  solium  injected  with 
coloured  size  and  quicksilver,  are  preserved  in  the 
Hunterian  collection,  (see  Nos.  843,  844,  845.) 
These  were  prepared,  during  the  life-time  of  John 
Hunter,  and  were  presented  to  that  great  anato- 
mist by  Sir  Anthony  Carlisle,  by  whom  they  are 
described  in  the  '  Observations  upon  the  Struc- 
ture and  (Economy  of  Taeniae,'  in  the  second  vo- 
lume of  the  Linnscan  Transactions,  (1794). 


Jig.  90),  and  are  united  by  transverse  canals 
(fi.fi  Jig-W)  passing  across  the  posterior  margins 
of  the  segments.  These  connecting  canals  are 
relatively  wider  in  the  Tania  solium  than  in  the 
Bothriocephalus  latus,  their  size  apparently 
depending  on  the  length  of  the  segments, 
which  is  much  greater  in  the  former  than  the 
latter.  Neither  the  transverse  nor  the  longi- 
tudinal vessels  undergo  any  partial  dilatations. 
The  chief  point  at  issue  respecting  the  digestive 
organs  of  the  Tape-worms  is,  whether  the  nu- 
triment is  imbibed  by  them  through  the  pores 
which  occur  at  the  sides  or  margins  of  each 
joint,  or  whether  the  entire  body  is  dependent 
for  its  nutriment  upon  the  anterior  mouths  from 
which  the  lateral  canals  commence.  The  re- 
sults of  numerous  examinations,  which  I  have 
made  with  this  view,  both  on  Bothriocephali* 
and  Taeniae,  have  uniformly  corresponded  with 
those  of  Rudolphi,  and  I  entirely  subscribe  to 
the  opinion  of  that  experienced  helminthologist, 
that  the  marginal  or  lateral  orifices  of  the  seg- 
ments are  exclusively  the  outlets  of  the  gene- 
rative organs. 

In  some  species  of  Tape-worm,  as  the  Tania 
sphanocephalus,  in  which  no  ovaria  have  been 
detected,  there  has  been  a  corresponding  ab- 
sence both  of  lateral  and  marginal  pores,  while 
the  lateral  longitudinal  canals  have  been  pre- 
sent and  of  the  ordinary  size.    In  the  Tania 
solium  the  generative  pores  being  placed  at 
one  or  other  of  the  lateral  margins  of  the  seg- 
ments, the  ducts  of  the  ovary  and  testis  ( g,  h, 
Jig.  90)  cross  the  longitudinal  canal  of  that 
side,  and  give  rise  to  a  deceptive  appearance, 
as  if  a  short  tube  were  continued  from  the 
alimentary  canal  to  the  pore.     But  in  the 
Bothriocephalus   latus    and  Bothriocephalus 
Pythonis  the  generative  pores  open  upon  the 
middle  of  one  of  the  surfaces  of  each  segment, 
and  in  these  it  is  plain  that  the  lateral  nu- 
trient vessels  have  no  communication  with 
the  central  pores.  The  orifices  of  the  segments, 
in  short,  correspond  with  the  modifications  of 
the  generative  apparatus,  while  the  nutrient 
canals   undergo    no  corresponding  change. 
Nutrition  may  be  assisted  by  superficial  ab- 
sorption ;  and,  as  Rudolphi  suggests,!  the  se- 
parated segments  may  for  a  short  time  imbibe 
nutriment  by  the  open  orifices  of  the  broken 
canals  ;  but  setting  aside  cutaneous  absorption 
and  the  more  problematical  action  of  the  rup- 

*  Principally  on  that  species  which  infests  the 
intestines  of  the  large  serpent  commonly  exhibited 
in  this  country  the  Python  Tigris,  Dand.  And  we 
invite  the  attention  of  comparative  anatomists 
interested  in  this  point  to  an  injected  preparation 
of  one  of  these  worms  in  the  Museum  of  the  Royal 
College  of  Surgeons,  No.  846  A. 

t  "  Al.  Olfers  (de  veget.  et  anim.  p.  35) 
articulos  TamicB  singulos  ope  absorptionis  cutanea? 
perparum,  maxime  autem  ope  osculi  marginalis 
nutriri  contendit,  sed  osculum  hoc  vere  ad  genitalia 
pertinpre  in  capite  insequente  evincam.  Si  cl. 
vir  absorptionem  cutaneam  minoris  sestumat,  hac 
de  re  non  litigabo,  sed  res  alio  modo  explicari 
potest.  Annon  enim  ad  vasa  linearia  nutneniia, 
utrinque  longitudinaliter  decurrentia,  si  articulus 
solutus  est,  in  utroque  ejus  fine  utrinque  hiantia, 
absorbendi  ofncium  deferri  posset." — Synops.  Entoz. 
p.  585. 

K  2 


132 


ENTOZOA. 


tured  vessels,  the  head  of  the  Tape-worm  is 
the  sole  natural  instrument  by  which  it  im- 
bibes its  nutriment,  and  it  is  to  the  expulsion 
of  this  part  that  the  attention  of  the  physician 
should  be  principally  directed,  in  his  attempts 
to  relieve  a  patient  from  these  exhausting  para- 
sites. 

Trematoda. — Four  kinds  of  vessels  or  canals 
are  met  with  in  the  parenchymatous  body  of  the 
Trematode  worms,  viz.  digestive,  nutritive  or 
sanguiferous,  seminal,  and  ovigerous.  In  the 
genus  Monostoma,  the  digestive  canal  is  bifur- 
cated, each  branch  traverses  in  a  serpentine 
direction  the  sides  of  the  body,  and  they  are 
united,  in  some  species,  by  a  transverse  com- 
municating vessel  at  the  caudal  extremity ;  in 
others,  as  Monost.  mutabile,  they  converge  and 
terminate  in  an  arched  vessel  at  the  posterior 
part  of  the  body.  They  are  of  small  size,  and 
not  very  clearly  distinguishable  from  the  sangui- 
ferous vessels. 

In  the  Distoma  hepaticum,  the  digestive 
organs  are  more  distinctly  developed.  The 
oesophagus  is  continued  from  the  anterior  pore, 
and  forms  a  short  wide  tube,  shaped  like  an 
inverted  funnel.  Two  intestinal  canals  are 
continued  from  its  apex,  which  immediately 
begin  to  send  off  from  their  outer  sides  short 
and  wide  ccecal  processes,  and  continue  thus 
ramifying  to  the  opposite  end  of  the  body, 
but  have  no  anal  outlet.  Rudolphi*  states 
that  when  successfully  injected  with  mercury, 
more  minute  vessels  are  continued  from  the 
apices  of  the  digestive  canals,  which  form  a  net- 
work over  the  superficies  of  the  body.  A  similar 
dendritic  form  of  the  digestive  canal  obtains  in 
the  singular  genus  Diplozoon,  discovered  by 
Nordmann  in  the  gills  of  the  Bream;  the  central 
canal  and  ramified  ccecal  processes  in  this  En- 
tozoon  are  represented  (Jig.  328,  vol.i.  p.  654,) 
on  that  moiety,  which  is  opposite  the  left  hand 
of  the  observer :  on  the  other  moiety  the  vascu- 
lar system  alone  is  delineated.  The  latter  is  not, 
like  the  digestive  canal,  common  to  both  halves 
of  the  body,  but  consists  of  two  closed  systems 
of  vessels,  each  peculiar  to  its  own  moiety. 
Two  principal  trunks,  a,  a,  traverse  the  sides 
of  each  moiety,  preserving  a  uniform  diameter 
throughout  their  entire  course.  In  the  external 
vessels  marked  a,  a,  Nordmann  states  that 
the  blood  is  conveyed  forwards  or  towards  the 
head:  in  the  internal  ones,  it  passes  back- 
wards in  the  opposite  direction.  The  latter 
vessels  commence  by  many  minute  branches 
which  unite  in  the  space  between  the  oral 
suckers  and  the  anterior  extremity  of  the 
body,  and  terminate  between  the  disc  and 
suckers  at  the  posterior  extremity  of  the  body. 
The  exterior  or  ascending  vessels  begin  where 
these  disappear  and  pass  towards  the  opposite 
end  of  the  body :  both  trunks  freely  inter- 
communicate by  means  of  superficial  capil- 
laries. The  blood  moves  through  them  with 
great  rapidity,  but  without  being  influenced 
by  any  contraction  or  dilatation  of  the  vessels 
themselves.  The  circulation  continues  for 
three  or  four  hours  to  go  on  uninterruptedly  in 

*  Entoz,  Synopsis,  p.  583. 


each  moiety  of  the  Diplozoon,  after  they  have 
been  separated  from  one  another  by  a  division 
of  the  connecting  band.  The  blood  itself  is  per- 
fectly limpid.  It  should  be  observed,  with  refe- 
rence to  the  above  description,  that  the  appear- 
ance of  circulatory  movements  in  the  vessels  of 
the  Diplozoon  par adoxum  is  ascribed  by  Ehren- 
berg  (  Weigmann's  Arckiven,  1835,  th.  ii.)  and 
Siebold  (Ibid.  1836,  th.  ii.)  to  the  motion  of 
cilia  on  the  inner  surface  of  the  vascular  canals. 

In  the  genus  Diplostomum,  in  which  the 
nutritious  and  vascular  systems  characteristic 
of  the  Trematoda  are  peculiarly  well  displayed, 
(fig.  81,)  a  short  and  slightly  dilated  canal  is 
continued  from  the  mouth,  and  soon  divides 
into  two  alimentary  passages  or  intestines,  e,  e, 
which  diverge,  and  proceed  in  a  slightly  un- 
dulating course,  towards  the  hinder  sacciform 
appendage  of  the  body,  dilating  as  they  de- 
scend, and  ultimately  terminating  each  in  a 
blind  extremity,  f,f.  The  contents  of  this  long 
bifid  blind  alimentary  canal  are  of  a  yellowish 
brown  colour,  especially  in  old  individuals, 
and  consist  of  a  finely  granular  substance. 
As  there  is  no  separate  anal  aperture,  the  crude 
and  effete  particles  are  probably  regurgitated 
and  cast  out  by  the  mouth,  as  in  all  other 
Trematoda. 

The  posterior  projection  of  the  body,  g, 
Nordmann  compares  to  the  posterior  appen- 
dage in  the  Cercaria ;  it  is  terminated  by  a 
posterior  aperture  which  seems  to  be  the  ex- 
cretory outlet  of  some  secerning  organ  ;  since 
a  milky  fluid  is  sometimes  ejected  from  it 
with  force.  In  a  species  of  Distoma  ( Distoma 
clavatum,  Rud.)  which  I  recently  dissected, 


Fig.  81. 


ENTOZOA. 


133 


there  is  a  similar  aperture  which  forms  the 
outlet  of  a  vertically  compressed  sac  situ- 
ated between  the  chyle-receptacles  (see  Trans- 
actions of  the  Zoological  Society,  plate  4,  p.  381, 
pi.  41,  figs.  17, 18,  d,  g).  In  the  Diplostomum 
volvens  Nordmann  supposes  the  aperture  in 
question,  h,  to  be  the  termination  of  a  canal 
continued  from  the  oviduct.  Besides  this 
canal  the  posterior  appendage  of  the  body  is 
occupied  by  a  sac  of  a  corresponding  form 
containing  a  milky  fluid,  i,  i,  and  to  which 
the  term  of  chyle-receptacle  is  given  by  Nord- 
mann, as  was  previously  done  by  Laurer  to  a 
corresponding  cavity  in  the  Amphisioma  coni- 
cum.  The  nutritious  contents  of  this  canal 
would  seem  to  exude  through  the  parietes  of 
the  coecal  extremities  of  the  intestines,  as  no 
distinct  aperture  of  communication  is  obvious. 
Two  vessels,  k,  k,  are  continued  on  each  side 
from  the  anterior  and  external  part  of  the  chyle 
receptacle;  they  extend  forwards  to  the  anterior 
third  of  the  body,  and  are  there  broughtinto  com- 
munication by  a  transverse  vessel,  which  ex- 
tends across  the  dorsal  aspect  of  the  body.  From 
the  point  of  union  of  the  transverse  with  the 
external  lateral  vessels, a  vessel  is  continued  for- 
ward on  each  side,  appearing  as  the  continuation 
of  the  external  lateral  one.  These  vessels,  m,  m, 
are  reflected  inward  at  the  anterior  angles  of  the 
body,  and  unite  in  the  middle  line  to  form  the 
vessel,  n,  which  may  be  regarded,  according 
to  Nordmann,  as  representing  the  arterial 
trunk,  and  which  is  continued  to  the  posterior 
extremity  of  the  body,  distributing  branches  on 
each  side  throughout  its  whole  length.  Nord- 
mann observed  a  circulation  of  fluid  in  the 
vessels  marked  m,  m,  which  was  unaccom- 
panied by  any  pulsation,  and  which  may  there- 
fore be  compared  to  the 
Fig.  82.  cyclosisofthe  nutrient  fluids 
in  the  vessels  of  Polygas- 
trica,  Polypi,  and  other 
Acrita,  and  is  probably  due 
to  the  action  of  vibratile 
cilia. 

In  a  few  species  of  Pla- 
naria the  mouth  is  terminal 
and  anterior,  as  in  the 
Distornata ;  these  form  the 
subgenus  Prostoma  of 
Professor  Duges.*  In  the 
greater  nu  mber  of  these  non- 
parasitic Sterelmintha  the 
alimentarycanal  commences 
from  a  cavity  situated  at  the 
middle  of  the  inferior  sur- 
face of  the  body.  A  pro- 
boscis or  suctorious  tube  (a, 
fig.  82),  varying  in  length 
according  to  the  species,  is 
contained  in  this  cavity, 
from  which  it  can  be  pro- 
truded, and  the  mouth  is 
situated  in  the  form  of  a 
round  pore  at  the  extremity 
of  this  proboscis.  The  ac- 
tion of  this  tube  is  well  dis- 


Dendritic  digestive 
cavity,  Planaria 
lactea. 


Duges,  Annales  des  Sciences,  1828,  p.  16. 


played  when  a  hungry  Planaria  makes  an  attack 
upon  a  Nats  ;  it  then  wraps  its  flat  body  around 
its  prey  (see fig.  76,)  and  applies  to  it  the  extre- 
mity of  its  trumpet-shaped  sucker  ;  the  red- 
blood  of  the  little  Anellide  is  seen  to  dis- 
appear from  the  part  in  contact  with  the  sucker; 
and  if  the  body  of  the  Nais  be  broken  in  the 
conflict,  the  Planaria  directs  the  extremity  of 
the  proboscis  to  the  torn  and  bleeding  surface. 
After  a  meal  of  this  kind  the  digestive  canals 
of  the  Planaria  are  displayed  by  the  red  colour 
of  their  contents,  like  the  corresponding  parts 
of  the  Liver-fluke  when  filled  with  bile,  and 
they  greatly  resemble  the  latter  in  structure ; 
instead  of  two  canals,  however,  three  are  con- 
tinued from  the  base  of  the  proboscis ;  one  of 
these  is  central  (6),  and  passes  upwards  to  the 
anterior  extremity  of  the  body,  distributing  its 
vvide  coeca  on  either  side ;  the  other  two  (c,  c) 
descend,  almost  parallel  to  one  another,  and 
give  off  their  ccecal  processes  chiefly  from  the 
outer  margin,  as  in  the  Distoma.  The  Plunarice 
are,  equally  with  the  parasitic  Trematoda,  de- 
void of  an  anus :  and  the  remains  of  Poly- 
gastric  infusories  swallowed  by  them  have  been 
seen  to  be  regurgitated  by  the  proboscis.  Mi- 
nute nutrient  vessels  are  continued  from  the 
extremities  of  the  intestinal  cceca,  and  form  a 
very  fine  cutaneous  network,  which  communi- 
cate with  a  mesial  and  dorsal  canal  and  two 
lateral  vessels,  as  in  the  Diplostomum. 

Some  species  of  the  Trematode  Entozoa  are 
infested  by  parasitic  Polygastnca  which  belong 
to  the  Monads :  Nordmann  observed  some 
brown  corpuscles  by  the  sides  of  the  alimen- 
tary canal  of  a  Diplostdnium,  which  contained 
minute  particles  in  continual  and  lively  motion. 
On  crushing  the  corpuscles  between  plates  of 
glass  an  immense  concourse  of  the  moving 
atoms  escaped  :  they  were  smaller  than  the 
Monas  atomos  of  Miiller,  of  an  oval  form,  and 
of  a  clear  yellow  colour;  their  movements  were 
very  singular :  they  whirled  rapidly  round  on 
their  axis,  then  darted  forward  in  a  straight 
line,  whirled  round  again,  and  again  darted 
forward.  When  we  consider  that  the  Diplos- 
tomum itself  does  not  exceed  a  quarter  of  a 
line  in  length,  and  that  the  aqueous  humour 
of  a  single  eye  serves  as  the  sphere  of  existence 
to  hundreds  of  individuals,  what  views  does 
the  fact  of  the  parasites  of  so  minute  an  Ento- 
zoon  open  of  the  boundless  and  inexhaustible 
field  of  the  animal  creation  ! 

Acanthocephala.—The  worms  of  this  order, 
although  in  external  form,  in  the  development 
of  the  tegumentary  and  muscular  system,  and 
above  all  in  their  dioecious  generation,  they  ap- 
proach very  closely  the  Nematoid  Worms,  yet 
preserve  the  distinguishing  character  of  the 
Sterelminthoid  class  in  the  structure  of  the 
digestive  organs.  In  the  Echinorhynclius 
gigas  the  mouth  is  an  extremely  minute  pore, 
situated  on  a  projectile  armed  proboscis,  the 
structure  of  which  we  have  already  described. 
From  its  posterior  part  are  continued  two  long 
cylindrical  canals  (e,  e,  Jigs.  83,84)  which  ad- 
here closely  to  the  muscular  fibres  by  their  outer 
side,  and  project  on  the  opposite  side  into  the 
triangular  cavity  (/i,  fig.  84)  left  between  the 


134 


ENTOZOA. 


fill 


ovaries  in  the  female  and 
testes  in  the  male.  They 
are  extremely  minute  at 
their  commencement,  but 
increase  so  as  to  be  readily 
visible  in  the  middle  of 
their  course.  They  are  trans- 
parent and  irregularly  dila- 
ted or  sacculated  at  inter- 
vals. Posteriorly  they  ter- 
minate in  a  cul-de-sac,  and 
have  no  anal  outlet.  They 
contain  a  transparent  in- 
odorous albuminous  liquid, 
give  off  no  visible  lateral 
branches,  and  do  not  com- 
municate together  in  any 
part  of  their  course.  Be- 
sides these  canals  we  find 
in  the  cavity  of  the  body 
of  an  Echinorhynchus  two 
long  wavy  tubes  called 
lemnisci,  (d,  d,  Jig.  83). 
They  are  attached  to  the 
lateral  parts  of  the  neck  by 
an  extremely  attenuated  an- 
terior extremity,  float  freely 
in  the  remainder  of  their 
extent,  and  terminate  in  an 
enlarged  obtuse  and  imper- 
forate extremity.  They  are 
of  a  whitish  colour,  tran- 
sparent in  the  living  worm, 
but  become  opake  after 
death;  they  present  consi- 
derable variety  of  form,  and 
would  seem  to  be  highly 
irritable  parts,  since  they  are 
not  unfrequently  found  fold- 
ed into  a  packet,  or  twisted 
both  together,  and  turned 
to  one  side  of  the  body. 
When  examined  with  a  high 
microscopic  power,  a  tran- 
sparent vessel  is  perceived 
running  through  the  centre 
and  ramifying  as  it  descends 
in  the  substance  of  the  lem- 
niscus, which  is  soft,  fragile, 
and  granular.  Cloquet  com- 
pares these  organs  to  the 
nutrient  processes  which 
project  into  the  abdominal 
cavity  of  the  Ascaris,  and 
they  are  also  regarded  by 
Goeze,  Zeder,and  Rudolphi 
as  belonging  to  the  organs 
of  nutrition. 

In  the  Cazlelmintha  or 
Cavitary  Entozoa,  the  ali- 
mentary canal  is  single  and  of  large  size,  and 
extends  nearly  in  a  straight  line  from  the  mouth 
to  the  anus,  which  are  at  opposite  extremities 
of  the  body.  With  regard  to  the  existence  of  an 
anal  outlet,  the  parasitic  Entozoon,  (  Syngamus 
irachealis,  Siebold,)  which  infests  the  windpipe 
of  our  common  Gallinaceous  Birds,  presents  an 
exception.  It  was  supposed  by  Montague  to  be 
a  singleindividual  with  two  pedunculate  mouths: 


Digestive  and  gene- 
rative organs,  Echi- 
norhynchus gigas, 
female. 


Transverse  section  of  Echinorhynchus  gigas. 

and  by  Rudolphi  was  placed  in  the  same  group 
as  Distoma  furcatum,  which  is  a  true  double- 
necked  Trematode  worm.  But  the  digestive 
system  has  the  essential  character  of  the  ccelel- 
minthic  structure,  the  intestine  floating  freely 
in  an  abdominal  cavity.  The  orifice  at  the 
extremity  of  the  smaller  or  male  branch  leads 
to  a  muscular  oesophagus,  which  is  continuous 
with  a  somewhat  broader  reddish-brown  intes- 
tine, continued  in  a  tortuous  manner  down  the 
neck,  and  terminating  in  a  cul-de-sac  prior  to 
the  confluence  of  the  extremity  of  this  branch 
with  the  body  of  the  female.  The  mouth  of 
the  larger  branch,  which  is  the  true  continua- 
tion of  the  larger  and  single  body,  leads  first 
to  a  horny  basin-like  cavity,  which  communi- 
cates by  an  opposite  pore,  surrounded  by  six 
horny  hooks  or  teeth,  with  the  oesophagus, 
from  which  a  similar  reddish-brown  intestine 
is  continued,  but  in  a  more  tortuous  manner 
than  in  the  male,  through  the  whole  body,  ter- 
minating in  a  cul-de-sac  at  the  caudal  extre- 
mity. In  both  intestinal  canals  are  molecules 
of  apparently  the  colouring  matter  of  blood. 
Their  inner  surface  is  reticulate. 

In  the  freedom  of  these  intestines  from  the 
muscular  parietes  of  the  body,  and  in  the  cy- 
lindrical form  of  the  latter,  we  have  a  close 
affinity  to  the  Nematoid  type:  but  the  intestine 
is  blind — without  an  anal  outlet.  It  is  not, 
however,  bifurcate,  as  in  the  true  Trematoda. 

In  the  genus  Linguatula  or  Pentastonia  of 
Rudolphi,  the  intestine  is  a  simple  straight 
tube,  and  is  surrounded  by  the  convolutions 
of  the  oviduct :  the  two  intest inula  cceca  with 
which  Rudolphi  describes  the  alimentary  canal 
as  being  complicated,*  appertain  to  the  gene- 
rative system,  and  communicate  exclusively 
with  the  oviduct :  the  intestine  terminates  by 
a  distinct  anus  at  the  posterior  extremity  of 
the  body. 

In  the  Nematoidea  the  intestine  is  also 
frequently  concealed  in  a  part  of  its  extent  by 
the  coils  of  the  genital  tubes,  but  these  are 
disposed  in  masses  by  the  side  of  the  alimen- 
tary canal,  and  not  wound  around  it  as  in  the 
Linguatula:  in  most  species  the  alimentary 
canal  is  attached  to  the  internal  parietes  of  the 
abdominal  cavity  by  means  of  numerous  small 
laminated  or  filamentary  processes. 

In  the  Strongylus  gigas  the  mouth  (A,  Jig. 
71)  is  surrounded  by  six  papillae;  the  cesopha- 

*  .Synopsis  Ento?.  p.  534. 


ENTOZOA. 


135 


gus  (b,Jig..  95)  is  round  and  slightly  contorted, 
and  suddenly  dilates  at  the  distance  of  about  two 
inches  from  the  mouth  into  the  intestinal  canal; 
there  is  no  gastric  portion  marked  off  in  this 
canal  by  an  inferior  constriction,  but  it  is  conti- 
nued of  uniform  structure,  slightly  enlarging 
in  diameter  to  the  anus.  The  chief  pecu- 
liarity of  the  intestine  in  this  species  is  that 
it  is  a  square  and  not  a  cylindrical  tube,  and 
the  mesenteric  processes  pass  from  the  four 
longitudinal  and  nearly  equidistant  angles 
of  the  intestine  to  the  abdominal  parietes. 
These  processes,  when  viewed  by  a  high  mag- 
nifying power,  are  partly  composed  of  fibres 
and  partly  of  strings  of  clear  globules,  which 
appear  like  moniliform  vessels  turning  around 
the  fibres.  The  whole  inner  surface  of  the 
abdominal  cavity  is  beset  with  soft,  short, 
obtuse,  pulpy  processes,  which  probably  im- 
bibe the  nutriment  exuded  from  the  intestine 
into  the  general  cavity  of  the  body,  and  carry 
it  to  the  four  longitudinal  vessels,  which  tra- 
verse at  equal  distances  the  muscular  parietes. 
The  analogous  processes  are  more  highly  de- 
veloped in  the  Ascaris  lumbricoides,  in  which 
species  we  shall  consider  the  digestive  and 
nutritive  apparatus  more  in  detail. 

The  mouth  (d,  fig.  87  and  fig.  85)  is  sur- 
rounded with  three  tubercles,  of  which  one  is 
superior  (a,  fig.  85),  the  others  inferior  (b,  b) ; 
they  are  rounded  externally,  triangular  inter- 
nally, and  slightly  granulated  on  the  opposed 
surfaces  which  form  the  boundaries  of  the  oral 
aperture  (c).  The  longitudinal  muscles  of  the 
body  are  attached  to  these  tubercles ;  the  dorsal 
fasciculus  converges  to  a  point  to  be  inserted 
into  the  superior  one ;  the  ventral  fasciculus 
contracts  and  then  divides  to  be  inserted  into 
the  two  which  are  situated  below.  By  means  of 
these  attachments  the  lon- 
gitudinal muscles  serve  to 
produce  the  divarication  of 
the  tubercles  and  the  open- 
ing of  the  mouth ;  the  tu- 
bercles are  approximated  by 
the  action  of  a  sphincter 
muscle. 

The  oesophagus  (e,fig. 
Head  and  mouth  of  87)  is  muscular  and  four 
AscarU  lumbricoides.  or  five  lines  in  length,  nar- 
row, slightly  dilated  pos- 
teriorly, and  attached  to  the  muscular  pa- 

Fig.  86. 


Fig.  85. 


Transverse  section  of  Ascaris  lumbricoides,  magnified. 


rietes  of  the  body  by  means  of  slender,  radiated 
filaments :  its  cavity  is  occupied  by  three  lon- 
gitudinal ridges,  which  meet  in  the  centre  and 
reduce  the  canal  to  a  triangular  form.  The 
oesophagus  is  separated  by  a  well-marked  con- 
striction from  the  second  part  of  the  digestive 
canal,  which  in  the  rest  of  its  course  presents 
no  natural  division  into  stomach  and  intestine. 
The  anterior  portion  of  the  canal  is  attached 
by  filaments,  as  in  the  Strongylus,  to  the  pro- 
cesses and  lining  membrane 
Fig.  87.  of  the  abdominal  cavity.  Those 
rf  which  come  off  from  the  sides 

of  the  canal  (d,  d)  communi- 
cate with  the  nutritious  vessels 
and  appendages,  and  in  pass- 
ing from  the  intestine  they 
diverge  and  leave  on  each  side 
a  triangular  space,  of  which 
the  base  corresponds  to  the 
lateral  line  or  vessel  (e,  fig. 
80),  and  the  apex  to  the  side 
of  the  intestine.  These  lateral 
spaces  are  filled  with  a  serous 
fluid,  and  are  continuous  with 
the  common  cavity  contain- 
ing the  alimentary  and  gene- 
rative tubes.  About  the  mid- 
dle of  the  body  the  intestine 
becomes  narrower,  being  here 
surrounded  and  compressed 
by  the  aggregated  loops  of  the 
oviduct  or  testis,  and  the  me- 
senteric processes  or  filaments 
diminish  in  number,  and  at 
last  leave  the  intestine  quite 
free,  which  then  gradually  en- 
larges to  within  a  short  dis- 
tance of  its  termination  (h). 

The  parietes  of  the  intestine 
are  thin  and  transparent,  and 
easily  lacerable  ;  they  consist 
of  a  gelatinous  membrane,  the 
internal  surface  of  which  is 
disposed  in  irregular  angular 
meshes  and  transverse  folds, 
which  gradually  disappear  to- 
wards the  lower  part  of  the 
canal. 

The  soft  obtuse  processes 
(f, ./',  fig.  86)  analogous  to 
those  which  project  from  the 
lining  membrane  of  the  abdo- 
minal cavityin  the  Strongulus, 
acquire  a  considerable  deve- 
lopment in  the  Ascaris.  They 
arise  chiefly  in  the  dorsal  and 
ventral  regions,  and  are  con- 
tinued from  numerous  trans- 
verse bands  ( e,e,fig.  88)  which 
pass  across  the  body  from  one 
lateral  absorbent  vessel  to  the 
other.  In  the  anterior  third 
of  the  body  these  transverse 
bands  (vaisseaux  nourriciers, 
Cloquet,)  are  quite  concealed 
Digestive  and  gene-  ft  the  Passes  in  question 
rative  tubes,  Ascaris  (  appendices  nourriciers,  Clo- 
lumbrkoides,  male,  quet),  but  are  very  conspicu- 


136 


ENTOZOA. 


ous  at  the  posterior  part  of  the  body.  The 
nervous  chord  passes  at  a  right  angle  to  the 
transverse  bands  between  them  and  the  longi- 
tudinal muscles,  and  sometimes  is  included  in 
loops  of  the  former,  as  at  d,  fig.  88.  Both  the 
pendant  processes  and  the  transverse  bands  are 
composed  of  a  homogeneous  spongy  tissue, 
without  any  central  cavity,  and  appear  to  form 
a  nidus  of  nutrient  matter  like  the  fatty  omen- 
tal processes  in  higher  animals. 

The  longitudinal  lines  (c,c,fig.  86, 88), which 
extend  along  each  side  the  body  of  the  Ascaris 
Lumbricoides,  and  which  are  very  conspicuous 

Fig.  88. 


Nutritive  processes  and  vascular  canah  magnified, 
Ascaris  lumbricoides. 


externally  through  the  transparent  integument, 
consist  each  of  a  narrow  flattened  tract  of  opaque 
substance,  by  some  anatomists  considered  as 
nervous,  and  a  very  slender  vessel  which  ad- 
heres closely  to  the  outer  side  of  the  band. 
The  two  bands  become  expanded  at  the  an- 
terior extremity  of  the  body,  and  unite  in 
forming  a  circle  around  the  oesophagus  :  the 
vessels,  on  the  contrary,  become  detached  from 
the  bands,  and  pass  transversely  below  the 
oesophagus  to  anastomose  together,  forming  a 
simple  loop  or  arch,  the  convexity  of  which  is 
anterior.  By  pressure  the  reddish  fluid  con- 
tained in  these  vessels-  may  be  made  to  tra- 
verse them  backwards  and  forwards. 

With  respect  to  the  accessory  glands  of  the 
digestive  system  of  the  Entozoa,  I  have  hi- 
therto met  with  them  in  two  species  only  of 
the  Nematoidea,  in  both  of  which  they  pre- 
sented the  primitive  form  of  simple  elongated 


unbranched  cceca.  The  first  being  developed 
from  the  commencement  of  the  alimentary 
canal,  and  co-existing  with  a  pair  of  rudimen- 
tal  jaws,  must  be  regarded  as  salivary  organs. 
They  exist  in  a  species  of  worm  which 
infests  the  stomach  of  the  Tiger,  and  which 
I  have  recently  described  under  the  name 
of  Gnathostoma  aculeatum.*  They  consist 
of  four  slender  elongated  cceca,  communi- 
cating with  the  mouth,  and  gradually  increas- 
ing in  size  as  they  extend  backwards  into  the 
abdominal  cavity,  where  they  end  each  in  a 
cul-de-sac ;  they  are  placed  at  equal  distances 
around  the  alimentary  canal,  and  have  no  at- 
tachment except  at  their  open  anterior  extre- 
mity. The  length  of  each  ccecum  is  about 
one-twentieth  of  the  entire  alimentary  canal. 
Their  parietes  under  a  high  magnifying  power 
present  a  beautiful  arrangement  of  spirally 
decussating  fibres.  Their  contents  when  recent 
are  clear,  but  become  opaque  when  immersed 
in  alcohol.  That  the  Gnathostoma  is  not  the 
larva  of  an  insect  is  proved  by  the  complete 
development  of  the  generative  system,  which 
resembles  that  of  the  Ascarides,  and  by  the 
absence  of  a  ganglionic  nervous  system. 

The  second  example  of  an  accessory  digestive 
gland  occurs  in  a  species  of  Ascaris  infesting 
the  stomach  of  the  Dugong :  here  a  single 
elongated  ccecum  is  developed  from  the  in- 
testine at  a  distance  of  half  an  inch  from  the 
mouth ;  and  is  continued  upwards,  lying  by 
the  side  of  the  beginning  of  the  intestine,  with 
its  blind  extremity  close  to  the  mouth ;  from 
the  position  where  the  secretion  of  this  ccecum 
enters  the  intestine,  it  may  be  regarded  as  re- 
presenting a  rudimental  liver.f 

Respiratory  Organs. — The  Entozoa  have  no 
distinct  internal  or  external  organs  of  respi- 
ration. The  skin  in  many  of  the  Trematoda 
and  Acanthocephala  is  highly  vascular,^  and 
the  circulating  fluids  in  these  worms  may  be- 
.  come  oxygenated  by  contact  with  the  vascular 
°°o°&S^y  mucous  membranes  of  the  higher  organized 
animals  which  they  infest.  In  the  Planarim 
the  surrounding  water  is  renewed  upon  the 
vascular  surface  of  the  body  by  means  of  the 
currents  excited  by  the  action  of  vibratile 
cilia;  and  the  young  of  certain  species  of 
Distomata,  which  pass  the  first  epoch  of  their 
existence  under  the  form  of  Polygastric  In- 
fusoria, freely  moving  in  water,  are  pro- 
vided with  superficial  vibratile  cilia  arranged 
in  longitudinal  rows;  but  these  organj|  of  lo- 
comotion and  adjuncts  to  the  respiratory  pro- 
cess are  lost  when  the  Distomata  resume  their 
position  as  parasites  in  the  intestines  of  the 
Fishes  from  which  they  were  originally  ex- 
pelled. 

Excretory  glands. — As  an  example  of  an 
organ  of  excretion,  we  may  refer  to  the  glan- 
dular sac  lodged  in  the  enlarged  extremity  of 
the  Distoma  clavatum,  which  opens  externally 


*  Proceedings  of  the  Zoological  Society^ Nov.  5, 
1836. 

t  See  the  Preparation,  No.  429  A,  Mus.  Coll. 
Surgeons,  Phys.  Catalogue,  p.  121. 

X  Conf.  Echinorhynchus  vasculosus,Entoz.Synop. 
p.  581. 


ENTOZOA. 


137 


by  a  small  orifice  in  the  centre  of  that  part,* 
and  the  corresponding  cavities  from  which  a 
clear  or  milky  fluid  is  ejected  by  the  posterior 
pores  of  some  smaller  species  of  Distomaia 
and  Diplostomata.f 

Organs  of  generation. — The  generative  sys- 
tem in  the  Entozoa  presents  great  varieties 
in  the  form,  structure,  and  combination  of 
its  several  parts.  Sometimes  the  female  or 
productive  organs  alone  are  discernible.  In 
many  Cestoidea,  and  in  all  the  Trematoda, 
the  male  gland  is  present  and  communicates 
with  the  oviduct,  so  that  each  individual 
is  sufficient  for  itself  in  the  reproductive 
capacity.  In  the  Acanthocephala  and  Ne- 
matoidea  the  sexes  are  distinct,  and  a  con- 
currence of  two  individuals  is  required  for 
impregnation. 

No  trace  of  a  generative  apparatus  has  hither- 
to been  detected  in  the  Cystic  Entozoa.  They 
would  seem  to  be  gemmiparous,  and  to  have 
the  reproductive  power  diffused  over  the  whole 
cyst,  at  least  in  the  Acephalocysts,  in  which 
the  young  are  not  developed  from  any  special 
organ,  or  limited  to  any  particular  part  of  the 
cyst. 

The  ovaries  in  the  most  simple  of  the  Ces- 
toid worms,  as  the  Ligula,  are  situated  in  the 
centre  of  each  joint,  where  they  open  by  a 
transverse  aperture,  from  which  projects  a 
small  filamentary  process  or  lemniscus,  re- 
garded by  Rudolphi  as  a  male  organ.  In  the 
Bolhriocephali  the  ovaries  have  a  similar  po- 
sition, and  in  the  Bothriocephalus  latus  (Jig.  89) 
assume  a  stellated  figure,  with 
Fig.  89.  the  aperture  in  the  centre, 
T3  /,  which  is  situated  in  the  mid- 

dle of  each  joint.  In  the 
Bothriocephalus  microcephalus 
the  ovary  consists  of  one  or 
two  rounded  corpuscles  in  the 
centre  of  the  joints,  but  the 
generative  orifices  are  margi- 
nal and  irregularly  alternate, 
and  the  oviducts  may  be  dis- 
tinctly seen  passing  backwards 
to  them. 

In  the^.  Tenia  Candelabra- 
C  ria  a  sacciform  ovary  exists 

in  each  segment,  which  sends 
'©Sjj®        off  an  oviduct  to  the  marginal 
outlet.     Besides  which,  ac- 
^^(|P§'       cording  to  Rudolphi,  there  is 
(Gaj%}         a  longitudinal  canal,  uniting 
Ovarian  apertures  the  different  ovaries  together, 
and  ova,  Bothrio-  and  undergoing  a  partial  dila- 
cephalm  latus.       tation  at  the  anterior  part  of 
each  joint. — May  not  this  be 
the  male  organ  ? 
The  androgynous  structure  of  the  generative 
apparatus  is  very  well  displayed  in  the  Tape- 
worm of  this  country,  the  Tania  Solium. 

In  each  joint  of  this  worm  there  is  a  large 
branched  ovarium  (i,  jig.  90)  from  which  a 
duct  (/i)  is  continued  to   the  lateral  open- 


Pig.  90. 


*  See  Zool.  Trans,  pt.  iv.  vol.  i.  p.  381. 
ng.  18.    See  Nordmann,  loc.  cit.  p.  38. 
t  See  Nordmann,  loc.  cit.  p.  140. 


pi.  41. 


c  "  e 

Generative  organs  maynijied,  Tania 

ing.  The  ova  are  crowded  in  the  ovary ; 
and  in  those  situated  in  the  posterior  segments 
of  the  body,  they  generally  present  a  brownish 
colour,  which  renders  the  form  of  their  recep- 
tacle sufficiently  conspicuous.*  In  segments 
which  have  been  expelled  separately,  we  have 
observed  the  ovary  to  be  nearly  empty,  and  it 
is  in  these  that  the  male  duct  and  gland  is 
most  easily  perceived.  For  this  purpose  it  is 
only  necessary  to  place  the  segment  between 
two  slips  of  glass,  and  view  it  by  means  of  a 
simple  lens,  magnifying  from  twenty  to  thirty 
diameters:  a  well-defined  line  (g),  more  slender 
and  opake  than  the  oviduct,  may  then  be 
traced  extending  from  the  termination  of  the 
oviduct,  at  the  lateral  opening,  to  the  middle 
of  the  joint,  and  inclining  in  a  curved  or 

*  The  dendritic  ovarian  receptacles  can  also  be 
injected  with  mercury  or  coloured  size,  and  they 
have  been  regarded,  but  erroneously,  as  forming 
part  of  the  nutrient  apparatus. 


138 


ENTOZOA. 


slightly  wavy  line  to  near  the  middle  of  the 
posterior  margin  of  the  segment,  where  it  ter- 
minates in  a  small  oval  vesicle.  This,  as  seen 
by  transmitted  light,  is  sub-transparent  in  the 
centre  and  opaque  at  the  circumference,  indi- 
cating its  hollow  or  vesicular  structure.  The 
duct,  or  vas  deferens,  contains  a  grumous  se- 
cretion ;  it  is  slightly  dilated  just  before  its 
termination. 

In  this  species  therefore,  as  also  in  Amphis- 
toma  conicum,  the  ova  are  impregnated  in  their 
passage  outward.  But  in  several  species  of 
Distomata,  as  D.  clavigerum,  ovatum,  cirrige- 
rum,  and  in  the  Distuma  hepaticum,  the  ova 
escape  by  an  aperture  situated  near  the  base  of 
the  penis,  and  reciprocal  fecundation  exists. 
The  concourse  of  two  individuals  must  also  take 
place  in  those  species  of  the  genus  Monos- 
tomum,  which,  like  the  Monostomum  mutabile, 
are  viviparous,  and  in  which  the  orifices  of  the 
male  and  female  parts  are  distinct. 

All  the  Sterelmintha  of  the  Trematode  order 
are  androgynous;  but  the  generative  apparatus, 
instead  of  being  divided  and  multiplied  as  in 
the  Taniaz,  is  individualized,  and  its  several 
parts  receive  a  higher  degree  of  development. 
We  have  selected  the  figure  which  Nordmann 
has  given  of  the  Distoma  per  latum,  on  account 

Fig.  91. 

€f 


s 


Generative  organs,  Distoma  perlatum,  magnified. 

of  the  clearness  with  which  the  several  parts 
are  delineated,  but  it  must  be  observed  that  it 
deviates  in  some  remarkable  peculiarities  from 
what  may  be  regarded  as  the  Trematode  type 
of  the  reproductive  organs. 

The  specimen  is  seen  from  the  under  side, 
part  of  the  parietes  of  the  body  having  been 
removed  ;  a  is  the  oral  aperture,  b  the  oesophagus 


seen  through  fhe  transparent  integument,  c  d 
the  windings  of  the  beginning  of  the  simple 
digestive  cavity,  e  e  the  two  intestinal  prolon- 
gations, f  f  the  dilated  claviform  coecal  ter- 
minations of  the  intestines,  g  the  two  internal, 
and  h  the  two  external  trunks  of  the  vascular 
system  proceeding  to  the  anterior  part  of  the 
body ;  i  is  the  great  sacciform  uterus,  k  ap- 
parently glandular  bodies  contained  therein, 
I  m  the  two  testes,  which  are  beset  internally 
with  small  spines  or  cilia;  n  the  projecting 
cirrus  from  which  the  ova  are  expelled,  o  the 
terminal  dilatation  of  the  oviduct  which  com- 
municates with  the  testes,  p  p  p  p  convo- 
lutions of  the  oviduct  which  are  filled  with  ova, 
q  q  the  mass  of  ova  which  lies  above  the  ovi- 
duct, and  occupies  almost  the  whole  cavity 
of  the  body,  r  r  the  passages  by  which  the 
ovaries  communicate  with  the  uterus  or  dilated 
commencement  of  the  oviduct. 

The  generative  organs  present  some  varieties 
in  the  Planaria,  but  are  essentially  the  same 
as  in  the  Distomata.  In  the  Planaria  lactea 
the  penis  and  oviduct  are  situated  below,  and 
the  two  vesicular  and  secerning  parts  of  the 
apparatus  towards  the  upper  part  of  the  body. 
The  male  organ  (a,  Jig.  92)  consists,  according 


Fig.  92. 


to  the  researches  of  Professor  Duges,  of  two 
parts,  one  of  which  is  free,  smooth,  semi- 
transparent,  contractile,  and  always  divided 
into  two  portions  by  a  circular  constriction  ; 
it  is  traversed  by  a  central  canal,  susceptible 
of  being  dilated  into  a  vesicle,  and  is  open  at 
its  free  extremity,  which  is  turned  backwards  ; 
the  second  division  is  thicker,  more  opaque, 
vesicular,  adherent  to  the  contiguous  paren- 
chyma, and  receives  two  flexuous  spermatic 
canals  (6,  b).  The  free  portion  of  the  penis  is  con- 
tained within  a  cylindrical  muscular  sheath  (c), 
which  is  adherent  to  the  circumference  of  the 
base  of  the  intromittent  organ,  and  serves  to 
protrude  it  externally.  This  sheath  commu- 
nicates with  the  terminal  sac  of  the  female 
apparatus  near  its  outlet  by  a  projecting  orifice 
(d).  The  oviduct  (e)  opens  into  the  posterior 
part  of  the  terminal  sac :  it  is  a  narrow  tube 
which  passes  directly  backwards,  and  dividing 
into  two  equal  branches,  again  subdivides  and 
ramifies  amongst  the  branches  of  the  dendritic 
digestive  organ.  Besides  the  ovary  there  are 
two  accessory  vesicles  (gand/i),  communicating 
together  by  a  narrow  duct  (f  ),  and  opening 
into  the  terminal  generative  sac. 

M.  Baar  twice  witnessed  the  copulation  of 


ENTOZOA. 


139 


Planaria  in  the  species  Planaria  torva.  Upon 
separating  the  individuals,  he  perceived  a  long 
white  tube  projecting  from  the  genital  pore  of 
each,  proving  the  reciprocity  of  fecundation. 

Notwithstanding  the  complicated  apparatus 
above  described,  the  Planaria,  are  remark- 
able for  their  spontaneous  fissiparous  gene- 
ration, and  the  facility  with  which  detached 
or  mutilated  parts  assume  the  form  and  func- 
tions of  the  perfect  animal.  Fig.  92,  o,  repre- 
sents a  Planaria  lacteu,  with  the  anterior  part 
of  the  body  artificially  divided  in  the  longitu- 
dinal direction ;  Jig.  92,  e,  shews  the  same  in- 
dividual having  two  perfect  heads,  the  result 
of  the  preceding  operation. 

The  female  generative  organs  of  the  Lingua- 
tula  ( Pentastoma )  tanioicles  present  a  struc- 
ture in  some  respects  analogous  to  that  of  the 
DisUnna  pcrlatum:  the  ovary  (n,  n,  Jig.  78) 
is  a  part  distinct  from  the  tubular  oviduct, 
and  is  attached  to  the  integument  or  pa- 
rietes  of  the  body,  extending  down  the 
middle  of  the  dorsal  aspect.  It  consists  of 
a  thin  stratum  of  minute  granules ;  clustered 
in  a  ramified  form  to  minute  white  tubes, 
which  converge  and  ultimately  unite  to  form 
two  oviducts  (o,  o,  Jig.  78).  These  tubes  pro- 
ceed from  the  anterior  extremity  of  the  ovary, 
diverge,  pass  on  each  side  of  the  alimentary 
canal,  and  unite  beneath  the  origins  of  the  nerves 
of  the  body,  so  as  to  surround  the  oesophagus 
and  these  nerves  as  in  a  loop.  The  single  tube 
(p)  formed  by  the  union  of  the  two  oviducts 
above  described,  descends,  winding  round  the 
alimentary  canal  in  numerous  coils,  and  ter- 
minates at  the  anal  extremity  of  the  body.  The 
single  oviduct,  besides  receiving  the  ova  from 
the  two  tubes  (o,  o),  communicates  at  its  com- 
mencement with  two  elongated  pyriform  sacs 
{m,  m),  which  prepare  and  pour  into  the  ovi- 
duct an  opaque  white  secretion.  These  bodies, 
from  their  analogy  to  the  impregnating  glands 
in  the  Trematoda,  I  was  led  to  regard  (in  the 
description,  published  in  the  Zoological  Trans- 
actions, of  the  only  individual  of  this  interesting 
species  that  I  have  hitherto  been  able  to  pro- 
cure for  dissection,)  as  testes,  and  the  gene- 
ration of  the  Linguatula  to  be  androgynous, 
without  reciprocal  fecundation ;  individuals, 
however,  of  the  male  sex  have  since  been  de- 
scribed in  this  species  by  Miram*  and  Diesing. 

The  male  Linguatula  is,  as  in  dioecious 
Entozoa  generally,  much  smaller  than  the 
female :  the  generative  apparatus  consists  of 
two  winding  seminal  tubes  or  testes,  and  a 
single  vas  deferens,  which  carries  the  semen 
from  the  testes  by  a  very  narrow  tube,  and 
afterwards  grows  wider.  It  communicates 
anteriorly  with  two  capillary  processes,  or 
penes,  which  are  connected  together  at  their 
origin  by  a  cordiform  glandular  body,  repre- 
senting a  prostate  or  vesicula  seminalis.  The 
external  orifices  of  the  male  apparatus,  accord- 
ing to  Miram,  are  two  in  number,  and  are 
situated  on  the  dorsal  aspect  of  the  body,  just 
behind  the  head. 

Diesing,  however,  describes  the  male  Pen- 

*  Nova  Acta  Acad.  Natura=  Cuiios.  tom.xvii. 


tastomu  as  having  only  a  single  penis,  which 
perforates  the  interspace  between  the  second 
and  first  segments  of  the  body,  and  protrudes 
below  and  behind  the  oral  aperture. 

Much  interest  attends  the  consideration  of 
the  reproductive  organs  of  the  dioecious  En- 
tozoa, since  they  are  the  first  and  most  simple 
forms  of  the  animal  kingdom  which  present 
that  condition  of  the  generative  function.  In  the 
Acanthocephala  the  structure  of  the  generative 
apparatus  has  been  ably  elucidated  by  Cloquet 
in  the  species  which  commonly  infests  the 
Hog,  viz.  the  Echinorhynchus  gigas.  The  male 
organs  consist  of  two  testes,  two  vasa  defe- 
rentia,  which  unite  together  to  terminate  in  a 
single  vesicula  seminalis,  and  a  long  penis 
gifted  with  a  particular  muscular  apparatus. 
The  testes  (J',  ft,  Jig.  93)  are  cylindrical 
bodies,  pointed  at  both  ex- 
Fig.  93.  tremities,  of  nearly  the  same 
magnitude,  but  situated  one 
a  little  anterior  to  the  other. 
The  anterior  one  is  attached 
by  a  filamentary  process  (g) 
to  the  posterior  extremity  of 
the  proboscis :  the  posterior 
gland  is  connected  by  a 
similar  filament  to  the  in- 
ternal parietes  of  the  body. 
The  vasa  deferentia  (i), 
after  their  union,  form  seve- 
ral irregular  dilatations  (/c), 
which  together  constitute  a 
lobulated  vesicula  seminalis. 
This  reservoir  is  filled  with 
a  white  grumous  fluid  like 
that  which  is  found  in  the 
testes,  and  it  is  embraced 
posteriorly  by  the  retractor 
muscles  of  the  penis  (r,  r), 
which  form  a  kind  of  coni- 
cal sheath  for  it. 

A  small,  firm,white,  and 
apparently  glandular  body 
(q)  is  situated  at  the  point 
of  union  between  the  vesi- 
cula seminalis  and  the 
penis. 

The  penis  is  a  straight, 
cylindrical,  firm,  white  or- 
gan, and  in  the  retracted 
state  is  terminated  by  a  di- 
lated  portion  (o),  occupying 

,  „         the  posterior  extremity  of 

Male  organs  of  gene-   &   b   ,     fa        hj  ,  ^ 
ration,  Jzchinorhun-  {  '  .  .  r 

chus  gigas.  pears  when  the  mtromittent 
organ  is  protruded.  This 
action  is  produced  by  the  muscles  s,  s,  when 
the  penis  presents  the  form  of  a  short  broad 
cone,  adhering  by  the  apex  to  the  caudal 
extremity  of  the  body:  it  is  retracted  by  the 
muscles  r,  ;■,  above  described. 

The  female  organs  consist  of  two  ovaries 
and  one  oviduct.  The  former  are  long  and 
wide  cylindrical  canals,  which  of  themselves 
occupy  almost  the  whole  cavity  of  the  body 
extending  from  the  proboscis  to  the  tail  (//,  h, 
Jig.  83)  They  are  situated,  one  at  the  ventral, 
the  other  at  the  dorsal  aspects  of  the  body,  and 


140 


ENTOZOA. 


are  separated  in  the  greater  part  of  their  extent 
by  a  septum  :  see  fig.  84,  J]  g,  which  shows 
them  in  transverse  section.  They  contain  a 
prodigious  quantity  of  ova,  and  adhere  by 
their  outer  surfaces  very  firmly  to  the  muscular 
parietes  of  the  body. 

The  dorsal  ovary  opens  into  the  ventral  one 
by  an  oblique  valvular  aperture  about  an  inch 
distant  from  the  extremity  of  the  proboscis, 
anterior  to  which  the  common  cavity  extends 
forwards  between  the  lateral  lemnisci,  and 
terminates  by  a  conical  canal  {i,  fig.  83),  which 
is  attached  to  the  posterior  portion  of  the  pro- 
boscis. The  two  ovaries  terminate  in  a  dif- 
ferent manner  posteriorly,  the  dorsal  one  end- 
ing in  a  cul-de-sac,  the  ventral  becoming 
continued  in  a  slender  oviduct  (k),  which 
opens  by  an  extremely  minute  pore  at  the 
caudal  extremity  of  the  body  (/).  The  tissue 
of  the  ovaries  is  remarkable  for  its  trans- 
parency and  apparent  delicacy,  but  it  pos- 
sesses a  moderate  degree  of  resistance. 

The  generative  organs  in  the  Nematoidea 
are  upon  the  whole  more  simple  than  in  the 
Acanthocephala. 

The  testis  in  each  of  the  genera  is  a  single 
tube,  but  differs  in  its  mode  and  place  of  ter- 
mination, and  the  modifications  of  the  intro- 
mittent  part  of  the  male  apparatus  have 
afforded  good  generic  characters. 

Genitale  masculum,  spiculum  simplex,  is  the 
phrase  employed  by  Rudolphi  in  the  formula 
of  the  genus  Filaria,  and  this  appears  to  be 
founded  on  an  observation  made  on  the  Filaria 
jiapillosa,  in  which  he  once  saw  a  slender  spicu- 
lum projecting  from  near  the  apex  of  the  tail. 
According  to  the  recent  observations  of  Dr. 
Leblond,*  the  male-duct  in  the  Filaria  papil- 


Fig.  94. 


Penis  of  Ascaris  lumbricoides. 

*  "  Quelqucs  Materiaux  pour  servir  a  l'Histoirc 
dcs  Filaircs  ct  Strongles,  8vo.  Paris,  1836." 


losa  terminates  at  the  anterior  extremity  of 
the  body  close  to  the  mouth.  From  this 
aperture  the  slender  duct,  after  a  slight  con- 
tortion, is  continued  straight  down  the  body  to 
a  dilated  elongated  sac,  which  represents  the 
testis. 

In  the  Ascaris  lumbricoides  the  penis  {a,  fig. 
94)  projects  from  the  anterior  part  of  the  anus 
in  the  form  of  a  slender,  conical,  slightly  curved 
process,  at  the  extremity  of  which  a  minute 
pore  may  be  observed  with  the  aid  of  the  micro- 
scope. The  base  of  the  penis  (b)  communicates 
with  a  seminal  reservoir,  and  is  attached  to 
several  muscular  fibres,  destined  for  its  re- 
traction and  protrusion  :  the  reservoir  is  about 
an  inch  in  length,  and  gradually  enlarges  as  it 
advances  forwards :  the  testis  or  seminal  tube 
is  continued  from  the  middle  of  the  anterior 
truncated  extremity  of  the  reservoir;  it  pre- 
sents the  form  of  a  long,  slender,  cylindrical, 
whitish-coloured  tube,  extends  to  the  anterior 
third  of  the  body,  forming  numerous  convo- 
lutions and  loops  about  the  intestine,  and  its 
attenuated  extremity  adheres  intimately  to  the 
nutrient  vessels  of  the  dorsal  region  of  the 
body.  The  total  length  of  the  seminiferous 
tube  in  an  ordinary  sized  Ascaris  lumbricoides 
is  from  two  feet  and  a  half  to  three  feet.  Its 
contents,  when  examined  with  a  high  micro- 
scopic power,  consist  of  a  transparent  viscous 
fluid,  in  which  float  an  innumerable  quantity 
of  round  white  globules,  much  smaller  than 
the  ova  in  the  corresponding  tubes  of  the 
female.  In  the  genus  Trichocephalus  the  fila- 
mentary testis  is  convoluted  around  the  intes- 
tine in  the  enlarged  posterior  part  of  the  body. 
The  intromittent  organ  in  the  Trichocephalus 
dispar  is  inclosed  in  a  distinct  sheath,  which 
is  everted  together  with  the  penis,  and  then 
presents  the  form  of  an  elongated  cone  (c, 
Jig.  69),  adhering  by  its  apex  to  the  enlarged 
anal  extremity  of  the  body,  and  having  the 
simple  filiform  spiculum  or  penis  {d,fig.  69) 
projecting  from  the  middle  of  its  base. 

In  the  Strongylus  gigas  the  bursa  or  sheath 
of  the  penis  terminates  the  posterior  extremity 
of  the  body,  and  is  a  cutaneous  production, 
of  a  round,  enlarged,  truncated  form,  with  the 
spiculum  projecting  from  its  centre,  as  at  B, 
fig.  71.  In  other  species  of  Strongylus,  as  in 
the  Strongylus  inflexus,  the  bursa  penis  is  bifid, 
and  in  the  Strongylus  armatus  it  is  divided 
into  four  lobes :  the  obvious  functions  of  these 
appendages,  as  of  the  lateral  alaeform  cuta- 
neous productions  which  characterize  the  Phy- 
salopterte  and  Spiropterg,  is  to  embrace  the 
vulva  of  the  female,  and  ensure  an  effective 
intromission  and  impregnation  of  the  ova. 

In  the  genus  Cucullanus,  and  in  most  of  the 
smaller  species  of  Ascaris,  the  intromittent 
organ  consists  of  a  double  spiculum. 

This  is  also  the  case  in  the  Syngamus  tra- 
chealis,  the  parasitic  worm  before  alluded  to  as 
infesting  the  trachea  of  the  common  fowl,  and 
occasioning  the  disease  termed  the  '  Gapes.' 
In  this  species  the  male  individual  appears  as 
a  branch  from  the  body  of  the  female.  The 
testis  begins  near  the  middle  of  the  oesophagus 
by  a  slender  blind  extremity,  and  winds  round 


ENTOZOA. 


141 


the  gut,  as  it  descends,  gradually  enlarging,  to 
the  lower  part  of  the  intestine,  where  it  sud- 
denly contracts  and  runs  down,  as  a  very  slender 
canal,  to  near  the  vulva.  It  is  partly  covered 
by  two  long  slender  bodies  of  a  horny  sub- 
stance, representing  a  bifurcate  penis. 

From  this  comparison  of  different  genera 
of  the  Nematoidea,  it  is  seen  that,  although 
there  are  many  varieties  of  structure  in  the 
efferent  and  copulative  part  of  the  male  gene- 
rative apparatus,  the  essential  or  secerning  por- 
tion uniformly  consists  of  a  single  tube.  A 
like  uniformity  of  structure  does  not  obtain  in 
the  essential  parts  of  the  female  organs  :  in  a 
few  instances  the  ovary  is  single,  correspond- 
ing to  the  testis  in  the  male,  but  in  the  greater 
number  of  the  Nematoid  worms  it  consists  of 
two  filamentary  tubes. 

The  Strongylus  gigas  is  an  example  of  the 
more  simple  structure  above  alluded  to.  The 
single  ovary  commences  by  an  obtuse  blind 
extremity  close  to  the  anal  extremity  of  the 
body,  and  is  firmly  attached  to  the  termination 
of  the  intestine ;  it  passes  first  in  a  straight  line 
towards  the  anterior  extremity  of  the  body, 
and  when  arrived  to  within  a  short  distance 
from  the  vulva,  is  again 
Fig.  95.  attached  to  the  parietes 

of  the  body,  and  makes 
Jpjk  a  sudden  turn  back- 

»B  wards  (f,fig-  95);  it 

MvWRk  then  forms  two  long 

AwlHsm.  loops  about  the  mid- 

dle of  the  body  and 
returns  again  forwards, 
suddenly  dilating  into 
an  uterus  (e),  which  is 
three  inches  in  length, 
and  from  the  anterior 
extremity  of  which 
a  slender  cylindrical 
tube,  or  vagina,  about 
an  inch  in  length,  (e,d, 
Jig.  95)  is  continued, 
BWjpKK'  ft  X\  which  after  forming  a 
'  1  ■  small  convolution  ter- 

minates in  the  vulva, 
at  the  distance  of  two 
inches  from  the  ante- 
rior extremity  of  the 
body.  Rudolphi  was 
uncertain  as  to  the  ter- 
mination of  the  ovi- 
duct in  the  Strongylus 
gigas,  and  Professor 
Otto,  who  appears  to 
have  mistaken  its  blind 
commencement  for  its 
termination,  believed 
that  the  oviduct  opened 
into  the  rectum. 

The  theory  which 
had  suggested  itself  to 
Rudolphi  of  the  corre- 
lation of  a  simple  ovi- 
Anterior  extremity  of  the  duct  in  the  female  with 
Strongylus  gtgas,  showing  ^  splcmum  simplex 
the  commencement  oj  the  f  ,  r  .  A  t 
digestive  and  the  termina-  ot  tne  male,  and  Ot  a 
Hon  of  the  generative  tube,  double    oviduct  with 


the  spiculum  duplex,  receives  additional  dis- 
proof from  the  circumstance  of  the  uteri  and 
oviducts  being  double  in  the  Strongylus  in- 
Jiexus  and  Strongylus  armatus.  In  the  former 
species  (which  infests  the  bronchial  tubes  and 
pulmonary  vessels  of  the  Porpesse,  and  which 
I  once  found  in  the  right  ventricle  of  the  heart 
of  that  animal,)  each  of  the  two  female  tubular 
organs  may  be  divided  into  ovary,  oviduct, 
and  uterus :  the  ovary  is  one  inch  in  length, 
commences  by  a  point  opposite  the  middle 
of  the  body,  and,  after  slightly  enlarging, 
abruptly  contracts  into  a  capillary  duct  about 
two  lines  in  length,  which  may  be  termed  the 
oviduct,  or  Fallopian  tube,  and  this  opens 
into  a  dilated  moniliform  uterus  three  inches 
in  length ;  the  divisions  here  described  were 
constant  in  several  individuals  examined,  and 
cannot,  therefore,  be  considered  to  result  from 
partial  contractions.  Both  tubes  are  remark- 
ably short,  presenting  none  of  the  convolutions 
characteristic  of  the  oviducts  of  Ascaris  and 
Filaria,  but  extend,  in  a  straight  line,  (with 
the  exception  of  the  short  twisted  capillary 
communication  between  the  ovaria  and  uteri,) 
to  the  vulva,  which  forms  a  slight  projec- 
tion below  the  curved  anal  extremity  of  the 
body. 

The  reason  of  this  situation  of  the  vulva 
seems  to  be  the  fixed  condition  of  the  head 
of  this  species  of  Strongylus.  In  both  sexes 
it  is  commonly  imbedded  so  tightly  in  a  con- 
densed portion  of  the  periphery  of  the  lung  as 
to  be  with  difficulty  extracted ;  the  anal  extre- 
mity, on  the  contrary,  hangs  freely  in  the 
larger  branches  of  the  bronchi,  where  the 
coitus,  in  consequence  of  the  above  dispo- 
sition of  the  female  organs,  may  readily  take 
place. 

In  the  Strongylus  armatus  the  two  oviducts 
terminate  in  a  single  dilated  uterus,  and  the 
vulva  is  situated  at  the  anterior  extremity  of 
the  body,  close  to  the  mouth. 

We  find  a  similar  situation  of  the  vulva  in 
a  species  of  Filaria,  about  thirty  inches  in 
length,  which  infests  the  abdominal  cavity  of 
the  Rhea,  or  American  Ostrich.  The  single 
portion  of  the  genital  tube  continued  from  the 
vulva  is  one  inch  and  a  quarter  in  length ; 
it  then  divides,  and  the  two  oviducts,  after 
forming  several  interlaced  convolutions  in  the 
middle  third  of  the  body,  separate ;  one  ex- 
tends to  the  anal,  the  other  to  the  oral  ex- 
tremities of  the  body,  where  the  capillary 
portions  of  the  oviducts  respectively  com- 
mence. 

In  the  Asearis  Lumbricoides  the  female  organs 
(Jig.  96)  consist  of  a  vulva,  a  vagina,  a  uterus, 
which  divides  into  two  long  tortuous  oviducts 
gradually  diminishing  to  a  capillary  tube, 
which  may  be  regarded  as  ovaries.  All  these 
parts  are  remarkable  in  the  recent  animal 
for  their  extreme  whiteness.  The  vulva  (d, 
Jig.  72,)  is  situated  on  the  ventral  surface  of 
the  body  at  the  junction  of  the  anterior  and 
middle  thirds  of  the  body,  which  is  generally 
marked  at  that  part  by  a  slight  constriction. 
The  vagina  is  a  slightly  wavy  canal  five  or  six 
lines  in  length,  which  passes  beneath  the  in- 


ENTOZOA. 


testine  and  dilates  into  the 
uterus  (/c,  fig.  96).  The 
division  of  this  part  soon 
takes  place,  and  the  cornua 
extend  with  an  irregularly 
wavy  course  to  near  the 
posterior  extremity  of  the 
body,  gradually  diminish- 
ing in  size;  they  are  then 
reflected  forwards  and  form 
numerous,  and  apparently 
inextricable,  coils  about 
the  two  posterior  thirds  of 
the  intestine.  Hunter  has 
successfully  unravelled 
these  convolutions,  and 
each  of  the  tubes  may  be 
seen  in  the  preparation  in 
the  Hunterian  Collection 
to  measure  upwards  of  four 
feet.  The  generative  organs 
contained  in  the  female,  or 
longer  branch  of  the  St/n- 
gamus  trachealis.  have  a  cor- 
responding structure  with 
those  of  the  Nematoidea. 
The  capillary  unbranched 
ovary  and  uterus  are  double, 
as  in  Ascaris,  Spiroptera, 
Filaria,  and  most  Stron- 
gyli.  The  vulva  is  in  the 
form  of  a  transverse  slit, 
and  is  situated  at  the  ante- 
rior third  of  the  body,  im- 
mediately below  the  attach- 
ment of  the  male  branch. 

In  the  Nematoidea  the 
male  individual  is  always 
smaller,  and  sometimes  dis- 
proportionately so,  than  the 
female.  At  the  season  of 
reproduction  the  anal  ex- 
tremity of  the  male  is  at- 
tached to  the  vulva  of  the 
female  by  the  intromission 
of  the  single  or  double  spi- 
culum,  and  the  adhesion  of 
the  surrounding  tumid  la- 
bia; and,  as  the  vulva  of 
the  female  is  generally  si- 
tuated at  a  distance  from 
either  extremity  of  her  body, 
the  male  has  the  appearance 
of  a  branch  or  young  indi- 
vidual sent  off  by  gemma- 
tion, but  attached  at  an 
acute  angle  to  the  body  of 
the  female.* 

In  the  Heteroura  andro- 
phora  of  Nitzch  (Herscli 
and  Gruber's  Encyclopae- 
die,  th.  vi.  p.  49,  and  th.  ix. 

*  See  Figures  of  Nematoid 
Entozoa  in  copulation,  in 
Bremser,  Icones  Heluiinthum 
tab.  iii.  fig.  8.  15.  ;  and  Gurlt, 
Lehrbuch  der  Patholog  :  Ana- 
tomic der  Haus-Saiigethiere, 
tab.  vi.  fig.  35. 


taf.  3.  f.  7.)  the  male  maintains  a'n  habitual  con- 
nexion with  the  female,  which  lias  a  horny  pre- 
hensile process  for  the  purpose  of  retaining  the 
male  in  this  position.  Here  there  is  no  conflu- 
ence of  the  substance  of  the  bodies  of  the  two 
sexes ;  the  individuals  are  distinct  in  their  su- 
perficies as  in  their  internal  organization.  But 
this  singular  species  offers  the  transitional  grade 
to  that  still  more  extraordinary  Entozoon,  the 
Syrtgamus  trachealis,  in  which  the  male  is  orga- 
nically blended  by  its  caudal  extremity  with  the 
female,  immediately  anterior  to  the  slit-shaped 
aperture  of  the  vulva,  which  is  situated  as  usual 
near  the  anterior  third  of  the  body.  By  this 
union  a  kind  of  hermaphroditism  is  produced ; 
but  the  male  apparatus  is  furnished  with  its 
own  peculiar  nutrient  system  ;  and  an  indivi- 
dual animal  is  constituted  distinct  in  every 
respect,  save  in  its  terminal  confluence,  with 
the  body  of  the  female.  This  condition  of 
animal  life,  which  was  conceived  by  Hunter  as 
within  the  circle  of  physiological  possibilities, 
(see  Anim.  (Economy,  p.  46,)  has  hitherto  been 
only  exemplified  in  this  single  species  of  Ento- 
zoon ;  the  discovery  of  the  true  nature  of  which 
is  due  to  the  sagacity  and  patient  research  of 
Dr.  Charles  Theodore  Von  Siebold. 

The  Entozoa  of  the  parenchymatous  class 
are  chiefly  oviparous,  those  of  the  cavitary  class 
for  the  most  part  ovoviviparous. 

The  germinal  vesicle  has  not  yet  been  dis- 
covered in  the  vitelline  substance  of  the  ova 
of  the  Acantlwcephata,  Trematodu,  or  Ces- 
toidca ;  but  it  is  distinctly  discernible  in  the 
ova  of  the  Nematoidea ;  I  have  also  observed 
and  have  figured  it  in  the  highly  organized 
ovum  of  the  Linguatula  tcenioides. 

The  ova  of  the  Tcenice  present  considerable 
varieties  of  size  and  form  in  different  species  ; 
Rudolphi  has  figured  seven  forms  of  these 
ova  in  the  Synopsis  Entozoorum,  (tab.  iii.)* 
Some  are  much  elongated  and  pointed  at  both 
extremities,  others  elliptical :  the  ova  of  the 
Bothriocep/ialus  lutus  are  of  the  latter  form, 
( L,  fig  89) ;  those  of  the  Tcenia  solium  are  sphe- 
rical, as  are  also  the  ova  of  Tcenia  jilifor  mis. 
In  some  species  the  development  of  the  em- 
bryo Tape-worm  has  been  observed  to  have 
distinctly  commenced  in  the  undischarged  ova, 
as  in  the  Tcenia  polymorpha.  In  dissecting  a 
Touraco  infested  by  the  'Tcenia  filiformis,  we 
found  that  the  segments  of  the  Taenia  in  which 
the  ova  were  most  developed  had  been  de- 
tached from  the  rest  of  the  body,  a  process 
remarkably  analogous  to  that  which  takes  place 
in  the  Lernece  and  Entomostraca,  where  the 
external  ovaries  are  cast  off,  when  charged  with 
mature  ova. 

A  few  of  the  Trematode  Entozoa,  as  the 
Monostoma  mutabile,  produce  the  young  alive  ; 
but  these  have  a  very  different  form  from  the 
parent.  It  would  seem  that  they  were  des- 
tined to  pass  a  transitional  state  of  their  ex- 
istence in  a  fluid  medium  permeated  by  light, 
since  two  coloured  ocelli  have  been  discovered 
on  the  head,  and  the  surface  of  the  body  is 
beset  with  locomotive  vibratile  cilia. f 

*  Synopsis  Entoz.  p.  505,  pi.  iii.  fig.  10,  11. 
f  See  Siebold,  in  Wcigmann's  Archiv.  1835. 


ENTOZOA. 


143 


The  ova  of  the  greater  part  of  the  Tremutoda 
are  excluded  prior  to  the  full  development  of  the 
fcetus  ;  they  are  generally  of  an  oval  but  some- 
times spherical  form,  and  many  of  them  singu- 
larly resemble  the  seeds  or  capsules  of  certain 
mosses,  in  having  a  small  circular  portion  of 
the  outer  covering  separate  from  the  rest,  and 
closing  the  cavity  of  the  egg  like  a  lid. 

Nordmann  has  studied  the  development  of 
the  young  of  the  Distoma  hians,  which  infest 
the  intestines  of  the  perch.  According  to  this 
excellent  observer  the  foetus  raises,  in  its  en- 
deavours to  slip  out  of  the  egg,  the  small  lid, 
and  writhes  about  for-  some  time,  being  still 
attached  to  one  point  of  the  egg.  In  about 
six  hours  it  succeeds  in  freeing  itself  from 
the  egg-coverings ;  and  at  this  period  it  differs 
in  every  respect  from  the  shape  of  the  parent 
animal ;  the  body,  which  is  of  a  mucous  con- 
sistence and  perfectly  transparent,  is  of  an  oval 
form  ;  the  anterior  mouth  forms  a  small  square- 
shaped  projection,  and  the  whole  surface 
of  the  body  is  beset  with  many  longitudinal 
rows  of  short  cilia,  which  are  in  rapid  and 
incessant  motion,  and  create  a  vortex  in  the 
surrounding  water,  similar  to  that  which  the 
Polygastric  Infusoria  produce.  The  little 
animal  having  its  anterior  extremity  diminish- 
ing to  a  point,  is  well  formed  for  swimming, 
and  by  means  of  its  vibratile  cilia,  quickly 
darts  out  of  the  field  of  vision  when  under  the 
microscope.  At  the  distance  of  one-third  of 
the  body  from  the  anterior  extremity  there  is 
a  single  coloured  eye-speck,  from  which,  when 
pressed  between  glass  plates,  there  escapes 
a  brilliant  blue-coloured  pigment.  Thus  orga- 
nized, the  young  of  the  intestinal  parasite  just 
described  move  to  and  fro  in  water  as  if  this 
were  their  natural  element,  and  approximate 
in  form  and  structure  most  closely  to  the  Poly- 
gastric Infusoria  of  the  genus  Paramaciuiii, 
Ehrenb.  In  this  state,  doubtless,  they  are 
ejected  by  the  Fish,  in  the  intestines  of  which 
they  were  originally  developed,  into  the  sur- 
rounding water,  and  when  again  received  into  the 
alimentary  canal  undergo  their  metamorphosis, 
lose,  like  the  Lerneae  and  Cirripedes,  the  organ 
of  vision  which  guided  the  movements  of  their 
young  and  free  life,  and  grow  and  procreate 
at  the  expense  of  the  nutrient  secretions  with 
which  they  are  now  abundantly  provided. 

In  the  Cceklmintha  the  young  cast  their  in- 
tegument, and  would  seem  in  some  species, 
as  the  Fittirkt  Medinaisis,  to  undergo  a  change 
in  the  form  and  proportions  of  the  extremities 
of  the  body,  but  they  do  not  possess  cilia  or 
ocelli,  as  in  the  Trematoda  above-mentioned. 

The  ova  of  the  Linguutula  are  of  an  oval 
form  :  the  germinal  vesicle  is  situated  near  the 
superficies  half-way  between  the  two  extremi- 
ties ;  the  vitelline  membrane  is  surrounded 
with  a  strong  cortical  membrane  :  the  develop- 
ment of  the  fcetus  takes  place  out  of  the  body. 
In  the  Strongylus  gigas,  Strongt/tus  injiexus, 
and  a  species  of  Trichosoma  infesting  the  in- 
testines of  the  Goatsucker,  we  have  found  the 
fcetus  completely  formed  in  the  ova  contained 
in  the  uterus  or  terminal  segment  of  the  gene- 
rative tube,  while  those  in  the  ovary  or  narrow 


commencement  of  the  same  part  were  still  occu- 
pied with  the  granular  matter  of  the  vitellus. 

The  mature  ova  of  the  Strongylus  gigas  are 
of  an  elliptical  form,  and  the  embryo  within 
is  plainly  seen  coiled  up  through  the  trans- 
parent coats  of  the  egg;  the  resemblance  which 
these  bear  to  the  Trichina  when  inclosed  in 
its  inner  cyst  is  very  striking :  the  hypothesis 
suggested  by  this  resemblance  need  only  be 
alluded  to  for  the  purpose  of  exciting  the  at- 
tention of  those,  who  may  hereafter  meet  with 
the  preceding  minute  muscular  parasite,  to  the 
existence  of  larger  Nematoid  Entozoa  in  other 
parts  of  the  body. 

Cloquet  describes  the  ova  in  the  beginning 
of  the  ovaries  of  the  Ascuris  Lwnbricoides  as 
consisting  of  rounded  linear  corpuscles, 
pointed  at  one  extremity,  thickened  at  the 
other;  in  the  middle  of  the  ovaries  they  as- 
sume an  elongated  triangular  form,  and  one 
of  their  angles  frequently  supports  a  small 
spherical  eminence ;  the  base  of  the  ovum 
adheres  to  the  parietes  of  the  oviduct,  the  apex 
projects  into  its  cavity.  In  the  enlarged  canals, 
which  he  terms  the  cornua  of  the  uterus,  the 
ova  are  unattached  and  of  a  conoid  or  irre- 
gularly triangular  figure.  In  the  uterus  itself 
they  have  assumed  an  ovoid  or  elliptical  form, 
are  surrounded  by  a  transparent  glairy  mucus, 
and  are  composed  of  a  transparent  cortical 
membrane,  perfectly  smooth  on  the  external 
surface,  and  filled  with  a  transparent  fluid,  in 
which  floats  a  linear  embryo,  disposed  either 
in  a  straight  line  or  coiled  up.  Cloquet  never 
observed  the  young  Ascarides  excluded  from 
the  egg  in  the  interior  of  the  uterus,  and  we 
equally  searched  in  vain  for  free  embryos  in 
the  generative  tubes  of  the  Strongylus  and 
Oxyurus  above-mentioned,  although  their  de- 
velopment in  regard  to  form  appeared  to  be 
complete  in  the  ovum ;  the  structure  of  the 
embryo  resembles  that  of  the  simpler  Vibriones, 
there  being  no  generative  tubes  apparent,  and 
the  cavity  of  the  body  being  occupied  by  a 
granular  parenchyma. 

With  respect  to  the  exclusion  of  the  ova 
in  these  and  similar  ovo-viviparous  Nematoid 
Entozoa,  it  would  appear  to  be  very  commonly 
accompanied  with  a  rupture  of  the  parietes 
of  the  body  and  of  the  generative  tube.  Ru- 
dolphi  observes,  with  respect  to  the  Cucullanus, 
"  Ovula,  verme  quieto,  per  intervalla  ex  vulva 
pullulent;  quin  eodem  disrupto,  quod  saepe 
accidit,  ovula  vel  embryones  ex  ovariis  pro- 
lapsis  parituque  ruptis  vi  quadam  et  undatim 
protroduntur." 

The  generation  of  the  Filaria  Mediaensis  is 
of  the  viviparous  kind,  and  the  progeny  is 
countless, — "  Filaria?  nostra,"  observes  Rudol- 
phi,  "  prole  quasi  farctae  sunt,  quod  si  harum 
longitudinem  illius  vero  minutiem  spectas, 
foetuum  multa  millium  millia  singulis  tribuit." 
What  is  most  remarkable  is,  that  these  em- 
bryos are  not,  as  in  the  Sti-ungt/lus  and  the 
Nematoid  genera  above-mentioned,  enveloped 
in  an  egg-covering,  nor  are  they  included  in  a 
special  generative  tube,  but  float  freely  along 
witli  a  granular  substance  in  the  common  mus- 
cular envelope  of  the  cavity  of  the  body. 


144 


ERECTILE'  TISSUE. 


M.  Jacobson,"  who  has  recently  published  a 
description  and  figures  of  the  young  Filaria 
Medinensis,  compares  the  body  of  the  mother 
to  a  tube  or  sheath  inhabited  by  the  young 
ones ;  and,  after  a  careful  examination  of  three 
individuals,  we  have  equally  failed  in  detecting 
either  generative  or  digestive  tubes  within 
the  muscular  sac  of  the  body.  The  external 
tunic  of  the  body  is  a  firm  subtransparent 
elastic  integument,  which,  examined  under  a 
high  magnifying  power,  presents  fine  trans- 
verse striae,  occasioned  most  probably  by  ad- 
herent muscular  fibres.  Within  this  tunic 
and  readily  separable  from  it  are  the  longitu- 
dinal muscular  fibres,  which  are  arranged  in 
two  fasciculi,  separated  from  each  other  by  two 
well-marked  intervals  on  opposite  sides  of  the 
body,  which  are  indicated  by  an  impression 
(or  furrow,  as  the  worm  dries  by  evaporation) 
on  the  exterior  surface.  When  from  long 
maceration  the  crisp  outer  integument  has 
become  separated  from  the  longitudinal  mus- 
cular bands,  these  might  be  mistaken  for  two 
tubes  contained   loosely  within   the  cavity. 

1  believe  that  these  muscular  bands  are  the 
tubes  Jibrineuses,  described  by  Dr.  Le  Blond  f 
as  the  alimentary  canal  and  intestine  in  the 
fragment  of  Filaria  Medinensis,  which  he 
dissected.  In  a  small  Filaria  Medinensis, 
containing  no  vermiculi,  we  have  also  failed 
to  discover  any  distinct  tubes  for  digestion  or 
generation. 

It  is  interesting  to  observe  that  the  young 
of  the  Filaria  Medinensis  do  not  resemble  the 
parent  in  form ;  one  extremity  is  obtuse,  the 
body  slightly  enlarges  for  about  one-fourth  of 
its  length,  then  gradually  diminishes  to  within 
a  third  of  the  opposite  extremity,  which  is 
capillary  and  terminates  in  the  finest  point. 
The  enlarged  part  of  the  worm  contains  a 
granular  substance,  and  is  coiled  upon  itself, 
and  presents  a  distinct  but  minute  annulation 
of  the  integument :  the  capillary  extremity  is 
smooth,  transparent,  and  generally  straight. 
The  Trichocephalus  dispar  closely  resembles 
in  its  external  form  the  foetus,  if  it  be  such, 
of  the  Filaria  Medinensis. 

BIBLIOGRAPHY.  — ■  Redi,  Osservazioni  intorno 
agli  animali  viventi  che  si  trovano  negli  animali 
viventi,  Firenze,  1684.  Block,  Abhand.  von  d. 
Erzeugung  Eingewerdwiirmer.  Berl.  1782.  Goeze, 
Versuch  einer  Naturgeschichte  der  Eingewerdwiir- 
mer, und  Naehtrag  dazn.  Leipz.  1782-1800.  Vol- 
lisneri,  Considerazioni  ed  esperienze  intorno  alia 
generazione  de  vermi  ordinarj  del  corpo  umano. 
Padova,  1782.  Werner,  Vermium  intestinalium, 
&c.  brevis  expositio.  Leipz.  1782.  Retzius,  Lec- 
tiones  publicae  de  Vermibus  intestinalibus,  Holm. 
1786.  Schrauh,  Verzeuhniss  der  bisherigen  hin- 
langlich.  bekannten  Eingeweidwiirmer,  Munch, 
1788.  Rudolphi,  Observ.  circa  vermes  intestinales, 

2  fasc.  Greifsw.  1793-95.  Rudolphi,  Entozoorum 
s.  vermium  intestinalium  historia  naturalis,  2  in  3 
vol.  Amst.  1808-9.  Rudolphi,  Entozoorum  Synop- 
sis, Berl.  1819.  Treutler,  Obs.  pathol.  anat.  ad 
helminthologiamcorp.  humani.  Leipz.  1793.  Zeder, 
Anleitung  zur  Naturgeschichte  des  Eingeweidwiir- 

*  Nouvelles  Annales  du  Museum  d'Histoire  Na- 
turelle,  torn.  iii.  p.  80,  pi.  v. 

f  Quelques  Mateiiaux  pour  servir  a.  l'Histoire 
des  Filaires  et  des  Strongles,  8vo.  1836. 


mer.  Bamb.  1803.  Olfers,  De  vegetativis  et  ani- 
matis  corporibus  in  corporibus  viventibus  reperiun- 
dis  comment.  Berl.  1816.  Fucker,  Brevis  Entozo- 
orum s.  verm,  intest.  expositio.  Vienna?,  1822. 
Bremser,  Ueber  lebende  Wiirmer  in  lebenden  Mens- 
chen.  Wien,  1819;  trad,  en  francais,  par  MM. 
Grundler  et  de  Blainville,  Paris,  1825.  Bremser, 
Icones  Helminthorum  Systema  Rudolphii  illus- 
trantes,  Wien.  1823.  Joerdens,  Entomologie  und 
Helminthologie  des  Mensch.  Koerpers.  2Bde.  Hof. 
1801-02.  Lidth  de  Jeude,  Recueil  des  figures  des 
Vers  intestinaux,  Leid.  1829.  Cloquet,  Anatomie 
des  Vers  intestinaux,  Paris,  1824.  Creplin,  Observ. 
de  Entozois,  Greifesw.  1825-29.  Schmalx,  De  En- 
tozoorum systemati  nervoso,  Leipz.  1827.  Ejus, 
Tabulae  anatomicae  Entozoorum,  Dresd.  1831.  Le 
Blond,  Quelques  materiaux  pour  servir  a  l'histoire 
des  filaires  et  des  strongles,  Paris,  1836.  Mehlis, 
Obs.  Anat.  d,e  distomate  hepatico  et  lanceolate, 
Gotting.  1825.  Nordinann,  Mikrographische  Bei- 
tr'age,  2  Bde.  Berlin,  1832.  Jacobson,  in  Nouv. 
Annales  du  Museum  d'Hist.  Nat.  torn.  iii.  Klein, 
in  Philos.  Trans,  for  1730.  Carlisle,  in  Trans,  of 
the  Linnean  Society,  vol.  ii.  Laennec,  in  Bulletin 
des  Sciences  de  l'Ecole  de  Medecine,  An  xiii. 
Home,  in  Philos.  Trans,  for  1793 ;  Frisch,  in 
Miscell.  Berolinensia,  torn.  iii. ;  and  for  further  re- 
ferences to  numerous  papers  on  the  natural  history 
of  particular  families  and  species,  vide  Reuss  s 
Repertorium,  &c.  Scientiae  Naturalis,  torn.  i.  Zoo- 
logia,  &c.  Gotting. ;  the  first  vol.  of  Rudolphi's 
Entozoorum  historia  naturalis,  and  Wieyemann's 
Archiv  fiir  Naturgeschichte  und  Vergleichende 
Anatomie. 

(R.  Owen.) 

ERECTILE  TISSUE,  (tela  erectilis ;  Fr. 
tissu  erectile ;  Germ,  das  erectile,  oder  schwell- 
bare  Gewebe,)  a  structure  composed  prin- 
cipally of  bloodvessels,  intimately  interwoven 
with  nervous  filaments.  This  tissue  in  its  ordi- 
nary state  is  soft,  flaccid,  and  spongy ;  but 
when  influenced  by  various  causes  of  excite- 
ment, whether  these  consist  of  stimuli  directly 
applied,  or  operating  through  the  medium  of 
the  sensorium,  it  exhibits  the  faculty  of  admit- 
ting an  influx  of  blood  much  greater  in  quantity 
than  what  is  sufficient  for  its  nutrition,  and  in 
virtue  of  which  it  suffers  a  state  of  turgescence 
giving  rise  to  a  swollen  condition,  with  more 
or  less  of  rigidity  and  increased  sensibility  of 
the  organs  into  the  structure  of  which  it  enters, 
and  which  state  has  been  long  known  by  the 
name  of  erection.  From  the  property  of  under- 
going erection  peculiar  to  this  tissue,  Dupuytren 
and  Rullier  first  applied  to  it  the  term  erectile, 
and  the  propriety  of  this  distinguishing  appel- 
lation is  now  very  generally  admitted  by  anato- 
mical authors. 

The  erectile  tissue  is  developed  in  various 
degrees  in  the  several  parts  of  the  animal 
economy  in  which  it  occurs ;  it  is  abundant 
and  particularly  evident  in  the  corpora  caver- 
nosa penis,  corpus  spongiosum  urethras,  clitoris, 
nymphae,  plexus  retifbrmis,  the  nipples  of  the 
mammary  glands,  less  marked  in  the  red 
borders  of  the  lips,  &c;  it  also  enters  into  the 
structure  of  the  papillae  of  the  skin  and  the 
villi  of  the  mucous  membranes  which  possess 
the  property  of  becoming  erected  in  the  per- 
formance of  their  functions,  as  is  exemplified  in 
the  papillae  of  the  tongue.  These  consist  of  the 
pulpy  terminations  of  nerves  enveloped  by  this 
tissue;  in  their  unexcited  state  they  appear 


ERECTILE  TISSUE. 


145 


small,  pale,  soft,  and  shrunken ;  but  when 
excited  to  erection,  they  become  increased  in 
size,  stiff,  red,  and  distended  with  blood,  at 
the  same  time  that  their  sensibility  is  remark- 
ably exalted.  The  foregoing  remarks  apply 
equally  to  the  cutaneous  papillae,  particularly 
those  on  the  pulpy  extremities  of  the  fingers, 
where  the  sense  of  touch  is  developed  in  its 
highest  degree  of  perfection. 

Erectile  tissue  has  also  been  recognised  in 
the  callosities  on  the  buttocks  of  some  of  the 
quadrumana,  in  the  comb  and  gills  of  the 
cock,  the  wattles  of  the  turkey,  and  in  the 
tongue  of  the  chamelion.*  It  is  not  improbable 
that  this  tissue  enters  into  the  structure  of  the 
and  Beclard  seems  disposed  to  consider 


that  it  exists  in  the  spleen,  as  well  from  the 
appearance  which  that  organ  presents  when  a 
section  of  it  is  made,  as  from  the  different 
states  in  which  it  is  found  on  opening  the 
bodies  of  animals;  being  sometimes  contracted 
and  corrugated  on  the  surface,  and  at  other 
times  plump,  smooth,  and  swollen. 

In  some  of  the  situations  above  enumerated, 
the  erectile  tissue  is  enclosed  in  a  fibrous  sheath 
which  limits  its  extent  and  determines  the  form 
of  the  organs  in  which  it  occurs ;  while  in  other 
situations  it  is  deployed  superficially,  as  in  the 
tegumentary  organs. 

It  is  in  the  corpora  cavernosa  penis  and 
corpus  spongiosum  urethrae,  however,  that  the 
erectile  tissue  has  been  more  especially  made 
the  subject  of  anatomical  and  physiological 
research  ;  and  the  results  of  the  investigations 
instituted  in  these  organs  have  been  rather 
inferred  from  analogy  than  directly  proved  as 
equally  applicable  to  it  in  all  other  situations 
in  which  its  existence  has  been  indicated. 

According  to  De  Graaf,  Ruysch,  Duverney, 
Boerhaave,  Haller,  and  Bichat,  the  cavernous 
bodies  of  the  penis  and  urethra  consist  of  a 
loose  and  elastic  spongy  tissue  formed  of  in- 
numerable cells,  into  which,  during  erection^ 
blood  is  poured  from  the  arteries,  and  from 
which  it  is  afterwards  removed  by  an  absorbing 
power  of  the  veins.  Such  an  opinion  wou^d" 
accord  with  the  appearances  observed  o&h 
examining  sections  of  this  structure  after  having 
been  inflated  and  dried,  but  careful  examina- 
tion of  it  when  previously  prepared  by  injec- 
tion, proves  the  foregoing  opinion  to  be  founded 
in  error. 

Vesalius,  who  appears  to  have  directed  his 
attention  to  the  particular  nature  of  this  struc- 
ture in  the  penis,  describes  it  as  composed  of 
innumerable  fasciculi  of  arteries  and  veins 
closely  interwoven,  and  included  in  an  invest- 
ing srieath. 

Malpighi  considered  it  as  composed  of  diver- 
ticula or  appendices  of  veins.  • 

Mascagni,  who  at  one  time  believed  in  the 
existence  of  cells  interposed  between  the  veins 
and  arteries,  in  consequence  of  subsequent 
researches  abandoned  that  opinion,  and  de- 
monstrated the  fact,  that  a  plexus  of  veins  with 
arteries  corresponding,  but  smaller  and  less 

*  On  the  structure  and  mechanism  of  the  tongue 
of  the  chamelion,  by  J.  Houston,  in  Transactions 
of  the  Royal  Irish  Academy,  vol.  xv. 
VOL.  II. 


numerous,  formed  the  corpus  spongiosum 
urethrae,  glans,  and  plexus  retiformis,  and  that 
the  arteries  entering  this  substance  terminated 
in  the  commencement  of  veins. 

Mr.  Hunter  remarked  that  the  corpus  spon- 
giosum urethrae  and  glans  penis  were  not 
spongy  or  cellular,  but  made  up  of  a  plexus  of 
veins,  and  that  this  structure  is  discernible  in 
the  human  subject,  but  much  more  distinctly 
seen  in  many  animals,  as  the  horse.  &c. 

Subsequent  researches  respecting  the  struc- 
ture of  the  penis  and  clitoris  of  man,  the  horse, 
elephant,  ram,  &c.  have  been  instituted  by 
Duverney,  Mascagni,  Baron  Cuvier,  Tiede- 
mann,  Ribes,  Moreschi,  Panizza,  Beclard, 
Weber,  &c  and  the  result  has  been  a  con- 
firmation of  the  views  developed  by  Vesalius, 
Malpighi,  and  Hunter. 

Moreschi,  in  particular,  has  shewn  that  the 
corpora  cavernosa  penis,  corpus  spongiosum 
urethrae,  and  glans  consist  of  a  congeries  of  fine 
vessels  in  all  animals,  whether  covered  by  skin, 
hairs,  spines,  or  scales ;  and  that  these  vessels, 
which  are  principally  veins,  are  characterized 
by  their  abundance,  tenuity,  and  softness, 
which  distinguish  them  from  the  veins  in  the 
muscles  and  other  parts  of  the  body. 

The  annexed  figure  (Jig.  97)  from  Moreschi 


Fig.  97. 


146 


ERECTILE  TISSUE. 


represents  the  plexiform  arrangement  of  the 
veins  apparent  on  the  surface  of  the  glans,  and 
which  empty  themselves  into  the  superficial 
veins  of  the  penis. 

Miiller  having  more  recently  investigated 
the  structure  of  the  penis,  has  announced  the 
discovery  of  two  sets  of  arteries  in  that  organ, 
differing  from  one  another  in  their  size,  their 
mode  of  termination,  and  their  use;  the  first 
he  calls  nourishing  twigs  ( raminutritii),  which 
are  distributed  upon  the  walls  of  the  veins  and 
throughout  the  spongy  substance,  differing  in 
no  respect  from  the  nutritive  arteries  of  other 
parts ;  they  anastomose  with  each  other  freely,, 
and  end  in  the  general  capillary  network. 

The  second  set  of  arteries  he  calls  arteria  heli- 
cmm.  In  order  to  see  these  vessels,  an  injection 
of  size  and  vermilion  should  be  thrown  into  a 
separated  penis  through  the  avteria  profunda : 
when  the  injection  has  become  cold,  the 
corpora  cavernosa  should  be  cut  open  longitu- 
dinally, and  that  portion  of  the  injection  which 
has  escaped  into  the  cells  carefully  washed  out. 
If  the  tissue  of  the  corpora  cavernosa  be  now 
examined  at  its  posterior  third  with  a  lens,  it 
will  be  seen  that,  in  addition  to  the  nutritious 
arteries,  there  is  another  class  of  vessels  of 
different  form,  size,  and  distribution.  These 
branches  are  short,  being  about  a  line  in  length 
and  a  fifth  of  a  millimetre  in  diameter;  they 
are  given  off  from  the  larger  branches  as  well 
as  from  the  finest  twigs  of  the  artery.  Although 
fine,  they  are  still  easily  recognised  with  the 
naked  eye  ;  most  of  them  come  off  at  a  right 
angle,  and  projecting  into  the  cavities  of  the 
spongy  substance,  either  terminate  abruptly  or 
swell  out  into  a  club-like  process  without  again 
subdividing.  These  vessels  appear  most  obvious 
and  are  most  easily  examined  in  the  penis  of 
man,  to  which  the  following  description  refers. 
These  twigs  branch  off  from  place  to  place, 
sometimes  alone,  and  sometimes  in  little 
bundles  of  from  three  to  ten  in  number;  these, 
as  well  as  the  former,  project  constantly  into 
the  cells  or  venous  cavities  of  the  corpora 
cavernosa  penis.  When  the  arteries  thus  form 
a  bundle,  they  arise  by  a  common  stem. 
Sometimes  such  a  vessel,  whether  it  proceeds 
from  the  artery  as  a  single  branch  or  as  part  of 
a  cluster,  divides  into  two  or  three  parallel 
branches,  which  also  either  terminate  abruptly, 
or  else  swell  out  near  their  extremity. 

Almost  all  these  arteries  have  this  character, 
that  they  are  bent  like  a  horn,  so  that  the  end 
describes  half  a  circle,  or  somewhat  more. 
When  such  a  branch  so  divides  itself,  there 
are  formed  doubly  bent  twigs  inclined  one  to 
the  other. 

Many  of  these  arteries  enlarge  towards  their 
end ;  this  enlargement  is  gradual,  and  is  greatest 
at  tome  little  distance  from  the  extremity,  so 
that  the  end  is  somewhat  conical,  terminating 
immediately  in  a  rounded  point  without  giving 
off  any  branches.  The  diameter  of  these  arte- 
rial twigs,  in  their  middle,  is  from  one-fifth  to 
one-sixth  of  a  millimetre :  those  which  branch 
off  from  the  trunk  of  the  arteria  profunda 
penis  are  no  larger  than  those  which  arise  from 
its  finest  twigs.    It  is  by  no  means  unusual  to 


observe  the  finest  twigs  of  the  arteria  profunda 
giving  off  branches  of  this  kind  which  seem 
much  thicker  than  the  twig  from  which  they 
arose.  The  annexed  figure  (fig.  98)  (from 
Muller's  Archiv.)  repre- 
sents a  portion  of  the 
arteria  profunda  penis  of 
man,  with  its  arteria 
helicina  somewhat  mag- 
nified. 

These  remarkable  arte- 
ries have  a  great  resem- 
blance to  the  tendrils  of 
the  vine,  only  that  they 
are  so  much  shorter  in 
proportion  to  their  thick- 
ness, whence  they  have 
received  the  name  arteria? 
helicina3.  Their  termi- 
nations may  also  be  com- 
pared to  a  crosier.  .By  a 
more  minute  examination 
of  these  vessels  either  with  the  lens  or  with  the 
microscope,  it  will  be  seen  that,  although  they 
at  all  times  project  into  the  venous  cavities  of 
the  corpora  cavernosa,  yet  they  are  not  entirely 
naked,  but  are  covered  with  a  delicate  mem- 
brane, which  under  the  microscope  appears 
granular  (Jig.  99). 

After  a  more  forcible  in- 
jection this  envelope  is  no 
longer  visible.  When  the 
arteries  form  a  bundle,  the 
whole  is  covered  by  a  slight 
gauze-like  membrane. 

With  respect  to  this  in- 
vesting membrane,  Profes- 
sor Miiller  appears-  to  con- 
sider it  as  performing  an 
important  part  in  producing 
the  phenomena  of  erection. 
These  tendril-like  arteries  have  neither  on 
their  surface  nor  their  extremities  any  openings 
discoverable  with  the  aid  of  the  microscope ; 
and  when  the  blood,  as  it  is  probable,  escapes 
from  them  in  large  masses  into  the  cells  of  the 
corpora  cavernosa  during  erection,  it  must 
either  traverse  invisible  openings,  or  pass 
through  small  openings  which  become  en- 
larged by  the  dilatation  of  these  arteries.  If 
the  great  number  of  the  tendril-like  branches 
of  the  arteria  profunda  be  compared  with  the 
very  fine  nutritious  twigs  of  the  same  vessel, 
it  is  evident  that  when  the  former  are  filled 
they  must  take  up  the  greater  part  of  the  blood 
of  the  arteria  profunda;  the  diameter  of  the 
profunda  therefore  not  only  includes  its  nu- 
tritious twigs,  but  also  the  tendril-like  branches, 
which  derive  their  blood  from  it,  yet  pro- 
bably allow  none  to  pass  except  during  erec- 
tion ;  therefore  the  blood  in  the  unerected  state 
only  traverses  the  nutritive  branches  and  ar- 
rives at  the  commencement  of  the  venous  cells 
in  smaller  quantities,  while  during  erection  it 
probably  passes  in  considerable  quantity  into 
the  cells  through  these  tendril-like  vessels. 

Professor  Miiller,  after  pointing  out  the  dif- 
ference between  the  tendril-shaped  vessels  and 
the  looped  vessels  discovered  by  Weber  in  the 


EXCRETION. 


147 


villi  of  the  placenta,  observes :  our  vessels  are 
simple;  they  bend  themselves  at  the  end,  but 
do  not  return  to  their  trunk  as  a  loop,  being 
simply  blood-containing  processes  of  the  ar- 
teries which  project  freely  into  the  cellular 
cavities  of  the  veins  of  the  corpora  cavernosa. 
These  vessels  are  most  numerous  in  the  pos- 
terior part  of  the  corpora  cavernosa ;  they 
occur  but  seldom  in  the  middle  and  anterior 
parts :  they  are  also  present  in  the  corpus 
spongiosum  urethra,  especially  in  the  bulb; 
here  also  they  become  less  frequent  anteriorly, 
and  as  yet  they  have  not  been  perceived  in  the 
glans.  They  are  much  more  difficult  of  detection 
in  the  corpus  spongiosum  urethra  than  in  the 
corpora  cavernosa,  where  they  are  very  easily 
exhibited,  especially  in  the  human  penis.  In 
no  other  animal  have  they  been  found  so  dis- 
tinct, or  so  uniform  in  their  existence  as  in 
man.  The  greater  development  of  these  arteries, 
adds  Professor  Miiller,  in  the  posterior  parts  of 
the  organ  corresponds  with  the  fact  of  erection 
being  always  earlier  evident  there,  as  if  the 
blood  distributed  itself  from  thence  into  the 
venous  cells. 

During  erection  blood  is  accumulated  in 
large  quantity  in  the  erectile  tissue,  but  the 
cause  and  mechanism  of  this  accumulation  are 
but  imperfectly  known.  Hebenstreit  ascribes 
it  to  a  living  power,  named  turgor  vitalis, 
which  exists  in  different  degrees  in  almost  all 
the  textures  of  the  animal  body,  but  most  dis- 
tinctly in  the  erectile  tissue.  It  still  remains, 
however,  to  be  proved  how  far  erection  de- 
pends on  mechanical  pressure  affecting  the 
veins  which  convey  blood  from  this  structure, 
and  consequent  retardation  of  the  venous  circu- 
lation ;  and  how  far  it  may  depend  upon  an 
increased  flow  of  blood  to  its  arteries  accompa- 
nied, or  perhaps  more  correctly,  occasioned  by 
an  increase  of  sensibility,*  or  whether  it  may  not 
depend  upon  the  influence  of  both  these 
causes  combined. 

•  Erectile  tissue  appears  sometimes  to  be  de- 
veloped as  a  morbid  production,  which  has 
been  described  under  the  names  of  varicose 
tumour,  aneurism  by  anastomosis,  na?vus  ma- 
ternus,  telangiectasis,  &c.  Its  anatomical  cha- 
racters are  of  the  same  kind  as  those  of  the 

[*  It  must  be  obvious  that  the  discovery  of  the 
arterial  lielicince  by  Professor  Miiller  favours  this 
theory  of  erection,  as  proving  the  existence  of  ves- 
sels distinct  from  the  ordinary  ones,  which  receive 
and  transmit  the  increased  supply  of  blood  to  the 
venous  cells.  What,  in  other  organs,  is  effected 
by  a  diminished  tonicity  in  the  arteries,  and  a  con- 
sequent enlargement  of  them,  ultimately  giving 
rise  to  the  tortuosity  so  striking  in  some  cases,  is 
here  effected  by  means  of  a  very  peculiar  set  of 
arterial  processes  superadded  to  the  ordinary  nutri- 
tious arteries  of  the  organ.  In  the  pregnant  uterus 
the  increased  supply  of  blood  is  provided  for  by  the 
enlargement  and  consequent  tortuosity  of  its  ordi- 
nary arteries  ;  there  are  no  sinuous  veins  here  to 
receive  the  new  supply  of  blood,  and  consequently 
erection  is  not  present ;  but  in  the  case  of  the 
penis  this  phenomenon  occurs  in  consequence  of 
the  existence  of  the  sinuous  veins  which  constitute 
so  large  a  proportion  of  the  corpora  cavernosa.  It 
will  be  interesting  to  inquire  whether  any  similar 
or  analogous  arrangement  of  arterial  processes 
exists  in  other  erectile  organs. — Ed.] 


normal  erectile  tissue ;  it  varies  in  size,  being 
more  or  less  circumscribed,  sometimes  sur- 
rounded by  a  thin  fibrous  envelope;  presenting 
internally  an  appearance  of  cells  or  spongy 
cavities,  but  consisting,  in  reality,  of  an  in- 
extricable congeries  of  arteries  and  veins  which 
communicate  by  innumerable  anastomoses 
like  capillary  vessels,  but  much  larger,  espe- 
cially the  veins.  It  is  difficult  to  inject  it  from 
the  arteries,  more  easy  from  the  neighbouring 
veins,  which  are  sometimes  much  enlarged. 
This  alteration  most  commonly  exists  in  the 
substance  of  the  skin,  where  it  sometimes  re- 
sembles the  comb  and  other  analogous  parts 
of  the  gallinaceae.  The  skin  of  the  face,  espe- 
cially that  of  the  lips,  is  frequently  its  seat. 
It  has  been  observed  in  the  subcutaneous  cel- 
lular tissue  in  masses  of  various  dimensions, 
sometimes  so  large  as  to  occupy  an  entire  limb. 
It  rarely  affects  the  internal  organs ;  sometimes 
it  extends  beneath  the  mucous  membrane  of 
the  mouth,  mostly  in  the  vicinity  of  the  red 
borders  of  the  lips.  This  production  is  occa- 
sionally affected  by  a  vibratory  motion  amount- 
ing sometimes  to  a  pulsation  resembling  that 
of  ananeurismal  tumour,  which  is  increased  by 
all  the  causes  which  excite  the  activity  of  the 
general  circulation  ;  it  cannot  be  properly  said 
that  this  structure  has  the  property  of  under- 
going erection.  It  is  often  congenital,  some- 
times it  appears  to  have  been  produced  by 
accidental  causes ;  it  sometimes  remains  un- 
altered ;  but  it  more  usually  continues  to  in- 
crease in  size  until  some  of  its  cavities  burst, 
when  hemorrhage  of  a  troublesome  description 
ensues. 

Beclard  considers  the  hemorrhoidal  tumours 
which  occur  round  the  anus  as  constituting  a 
variety  of  anormal  erectile  tissue. 

Bibliography.  —  Vesalius  de  corp.  hnmani 
fabrica,  lib.  v.  cap.  xiv.  Venet.  1564.  De 
Grauf  Regner,  De  virorum  organis,  &c.  p.  99  et 
seq.  Lugd.  Bat.  1668.  Malpighi  Marcelli  opera, 
omnia,  torn.  ii.  p.  221.  London,  1686.  Rui/sch 
FHd.,  Observatio,  C.  Amstel.  1691.  Haller,  Ele- 
menta,  lib.  ii.  sect.  i.  §24,  et  lib.  xxvii.  sect.  iii. 
4  10.  Mascagni,  Prodromo  della  grande  anatomia, 
Firenze,  1819.  Hunter  John,  On  certain  parts  of 
the  animal  economy,  Lond.  1786.  Moreschi  Alex. 
Comment,  de  urethras  corporis  glandisque  structura, 
Mediolani,  1817.  Duvernay,  in  comment.  Petro- 
polit.  torn.  ii.  p.  200.  Cuvier,  Lecons  d'anatomie 
comparee,  torn.  iv.  Paris,  1799 — 1805.  Tiedemtinn, 
in  Journal  complementaire,  torn.  iv.  p.  282. 
Hebenstreit,  G.  De  turgore  vitali  in  Brera  Sylloge, 
torn.  ii.  Duverney,  (Euvres  anatomiques,  torn.  ii. 
Paris,  1761.  Mascagni,  P.  Hist,  vasorum  lymphat. 
sect.  ii.  Scnis,  1787.  Beclard,  Anat.  generate, 
Paris,  1823.  Weber,  H.  E.  Allgemeine  anatomie, 
p.  415.  Braunschweig,  1830.  Craigie  David,  M.D. 
Elements  of  general  and  pathological  anatomy, 
Edin.  1828.  Miiller,  in  Archiv  fiir  Physiologic, 
Jahr  1835,  p.  202.  The  paper  of  Professor  Miiller 
has  been  very  ably  translaied  in  the  London  Me- 
dical Gazette,  No.  423. 

(J.  Hart.) 

EXCRETION.— This  term  is  applied  to  the 
formation  of  those  fluids  in  the  animal  economy, 
which  are  destined  to  no  useful  purpose  in  the 
system,  but  are  intended  to  be  discharged  from 
it,  and  the  retention  of  which  is  injurious  or 


148 


EXCRETION. 


even  fatal.  The  term  used  by  the  older  phy- 
siologists was  excrementitious  secretions.  Some 
general  observations  may  be  made  on  these  ex- 
cretions, with  the  view  both  of  stating  the  pre- 
sent extent  of  our  knowledge  on  this  mysterious 
subject,  and  of  pointing  out  the  importance  of 
an  arrangement  and  combination  of  facts  re- 
lating to  it,  which  are  usually  treated,  perhaps, 
in  too  unconnected  a  manner,  but  the  con- 
nexion of  which  is  already  perceptible,  and 
can  hardly  fail  to  be  satisfactorily  elucidated 
in  the  progress  of  physiology. 

When  we  shall  have  more  precise  informa- 
tion as  to  the  peculiar,  and  hitherto  obscure 
principles,  which  regulate  the  chemical  changes 
continually  taking  place  in  living  bodies,  it  does 
not  seem  unreasonable  to  anticipate,  that  a  dis- 
covery will  be  made,  connecting  the  excretions 
of  the  body  with  the  assimilation  of  the  food, 
and  with  the  nourishment  of  the  different  tex- 
tures, a  discovery  which  may  be  equally  as 
important  in  illustrating  the  chemical  phenome- 
na of  the  living  body,  as  that  of  the  circulation 
was  in  explaining  those  changes  which  come 
more  immediately  under  our  observation.  In 
the  mean  time,  we  can  point  out  a  great  deal  of 
contrivance,  connected  with  the  general  function 
of  excretion,  and  can  state  what  are  the  general 
injurious  results,  when  this  contrivance  fails  of 
its  intended  effect;  but  we  are  unable  to  explain 
how  the  contrivance  effects  its  purpose,  or  to 
point  out  any  general  law,  by  which  these  in- 
jurious results  are  determined. 

I.  We  may  state,  in  the  first  place,  that  the 
necessity  for  some  kind  of  excretion,  or  dis- 
charge of  certain  matter  from  the  organized 
frame,  corresponding  to  the  acts  of  nutrition, 
or  of  reception  and  assimilation  of  external 
matter,  is  a  law  of  vital  action,  applicable  to  all 
organized  beings  without  exception.  The  uni- 
versality of  the  excretion  of  carbon,  (whether 
pure,  or  in  the  form  of  carbonic  acid,  we  need 
not  now  inquire,)  has  been  established  by  the 
inquiries  of  Mr.  Ellis  and  others,  and  the  poi- 
sonous influence  of  the  carbonic  acid,  in  an  un- 
diluted state,  to  all  living  beings,  is  an  equally 
general  fact.  In  all  animals,  which  possess 
organs  of  such  size  and  distinctness  as  to  make 
their  economy  matter  of  observation,  other  excre- 
tions are  likewise  observed;  and  in  vegetables, 
it  is  not  only  certain  that  various  excretions, 
besides  the  exhalation  of  water  and  of  carbonic 
acid,  take  place,  but  it  is  even  believed  by 
De  Candolle,  that  all  the  peculiar  products 
of  vital  action,  excepting  only  gum,  sugar, 
starch,  and  lignine,  (which  have  nearly  the  same 
elementary  composition,  and  are  convertible 
into  one  another,)  and,  perhaps,  fixed  oils,  are 
applied  to  no  useful  purpose  in  the  economy, 
and  are  poisonous  to  the  plants  in  which  they 
are  formed,  if  taken  in  by  their  roots  and  com- 
bined with  their  sap;  so  that,  although  often 
long  retained  in  individual  portions  of  the 
plants,  they  all  possess  the  essential  characters 
of  excretions*  And  it  appears  to  be  well  ascer- 
tained by  the  observations  of  De  Candolle  and 
of  Macaire,  that  at  least  great  part  of  the  proper 

*  Physiol.  Veget.  p.  217. 


juices  of  vegetables,  which  descend  chiefly  by 
their  bark,  and  are  expelled  into  the  soil,  are 
destined  to  excretion  only,  and  are  noxious  to 
plants  of  the  same  species,  or  even  of  the  same 
families,  if  growing  in  that  soil  (although  often 
useful  to  the  growth  of  plants  of  different  fami- 
lies) ;  and  this  principle  has  been  happily  ap- 
plied by  the  former  author  to  explain  the  neces- 
sity of  rotation  of  crops  of  different  natural 
families,  to  prevent  deterioration  of  the  produce.* 

As  this  necessity  of  excretion  appears  to  be 
so  general  an  accompaniment  of  the  vital  action 
of  all  organized  beings,  it  seems  obvious  that 
there  must  be  some  general  law,  which  deter- 
mines the  noxious  quality  of  these  products  of 
that  action,  and  imposes  the  necessity  of  their 
expulsion.  Yet  it  is  certain  that  the  chemi- 
cal elements  which  pass  off  in  the  excretions, 
are  the  same  which  are  found  in  the  textures  of 
the  animal  body,  and  in  the  nourishment,  which 
is  essential  to  animal  life. 

It  would  appear,  therefore,  that  the  noxious 
property  belongs  to  certain  combinations  only 
of  these  elements,  which  are  formed  in  the  course 
of  the  chemical  changes  in  living  beings,  and 
which,  when  once  formed,  must  either  be  ex- 
pelled from  the  body,  or  else  laid  up  in  cells 
appropriated  for  the  purpose,  (as  in  the  case  of 
the  resins  and  volatile  oils  in  vegetables,  and  of 
the  bile  in  the  gall-bladder  in  animals,)  and  kept 
out  of  the  mass  of  the  nourishing  fluid. 

There  is  one  general  fact,  on  which  much 
stress  has  been  justly  laid  by  Dr.  Prout,  which 
is  confirmed  by  M.  Raspail,  and  which  may, 
perhaps,  be  concerned  in  determining  the 
noxious  qualities  of  certain  compounds,  in  liv- 
ing beings,  viz.  that  although  the  elements 
which  enter  into  the  composition  of  organized 
bodies,  readily  combine,  in  other  circumstances, 
so  as  to  form  crystals,  yet  the  peculiar  combi- 
nations which  they  form  in  all  the  textures 
which  are  essential  constituents  of  those  organic 
structures  are  never  crystalline.  When  a  crystal 
occurs  in  an  organized  body,  according  to  Dr. 
Prout,f  it  is  always  either  the  result  of  disease, 
or  of  some  artificial  process,  or  it  is  part  of  an 
excretion,  separated  from  the  nourishing  fluid 
and  from  the  useful  textures.!  Every  one  of 
these  textures  contains,  even  in  its  minutest 
particles,  saline  and  earthy,  as  well  as  animal 
or  vegetable  matter ;  §  but  the  combinations  are 
always  so  arranged,  by  the  powers  of  life,  that 
these  saline  and  earthy  particles  are  always  dif- 
fused through  membranes,  fibres,  or  cells,  never 
concentrated  in  crystals.  On  the  other  hand, 
the  elements  constituting  the  peculiar  matters  of 
the  excretions  are  generally  in  such  a  state  of 
combination  as  readily  to  assume  the  crystalline 
form,  either  alone,  or  in  the  simplest  farther 
combinations  of  which  they  are  susceptible  ; 
and  it  seems  possible,  that  this  circumstance 
may  be  part  at  least  of  the  cause  which  necessi- 
tates their  expulsion.    This  is  only  matter  of 

*  Ibid.  p.  249,  and  p.  1496. 

t  Lectures  in  Medical  Gazette,  vol.  viii. 

|  "  Jamais  je  n'ai  apercu,"  says  Raspail,  "  de 
cristaux  dans  le  sein  d'une  cellule  vivante  et  d'ac- 
croisemtnt,"  Raspail,  Chimie  Organique,  §  1378. 

§  Ibid.  $1390. 


EXCRETION. 


149 


speculation,  but  that  somp  such  general  prin- 
ciple determines  the  incompatibility  of  the  mat- 
ters of  the  excretions  with  the  life  of  the  struc- 
tures in  which  they  are  formed,  can  hardly  be 
doubted. 

II.  Although  the  necessity  of  various  excre- 
tions is  obvious,  there  is  a  difficulty,  both  in 
the  case  of  animals  and  vegetables,  in  fixing  on 
those  products  of  vital  action  which  come  exclu- 
sively under  this  denomination  ;  and  it  appears 
certain,  that  some  of  the  organs  of  excretion 
(such  as  the  lungs)  are  at  the  same  time  de- 
stined to  other  purposes,  particularly  absorption  ; 
and  even  that  part  of  certain  excreted  fluids 
(such  as  the  bile)  is  employed  likewise  in  the 
work  of  assimilation.  But  it  is  certain  that  the 
lungs  or  gills,  the  skin,  the  intestines,  and  the 
kidneys,  are  the  outlets  for  excreted  matters  in 
all  vertebrated  animals. 

1.  There  can  be  no  doubt  that  the  watery 
vapour  and  carbonic  acid  which  are  exhaled 
from  the  lungs,  are  strictly  excretions,  although 
it  is  still  doubted  by  some  physiologists,  whe- 
ther the  latter  substance  is  truly  exhaled,  or 
rather  formed  at  the  lungs;  on  the  latter  sup- 
position we  should  say,  that  the  excretions  of 
the  lungs  are  water  and  carbon.  It  appears 
certain,  from  some  experiments  of  Dr.  Gordon, 
that  no  animal  or  saline  matter  escapes  by  this 
outlet.  The  total  amount  of  loss  by  this  excretion 
in  twenty-four  hours,  in  a  middle-sized  man,  has 
been  stated  by  Lavoisier  and  Seguin  as  aver- 
aging about  fifteen  ounces ;  and  it  must  be  re- 
membered, that  as  we  have  good  evidence  of 
very  considerable  absorption  at  the  lungs,  the 
whole  quantity  of  matter  excreted  must  consi- 
derably exceed  this  weight.  Indeed,  Mr.  Dal- 
ton  estimates  the  exhalation  of  watery  vapour 
only  from  the  lungs  at  twenty-four  ounces  in 
the  day.  Some  have  estimated  the  quantity  of 
carbon  alone  escaping  in  this  way  in  the  day  at 
eleven  ounces;  but  this  estimate  is  probably 
exaggerated.  It  seems  to  be  ascertained  by  the 
experiments  of  Dr.  Edwards,  of  Despretz,  and 
Collard  de  Martigny,  that  there  is  at  times  an 
obvious  exhalation  of  azote  by  the  lungs;  and 
Dr.  Edwards  expresses  an  opinion  that  there 
is  probably,  at  all  times,  both  an  exhalation 
and  absorption  of  that  gas,  but  that  these 
processes  in  general  nearly  compensate  one 
another.  According  to  Dr.  Prout's  views,  re- 
cently, though  briefly,  announced,  we  may,  per- 
haps, state  the  source  and  cause  of  the  forma- 
tion of  the  carbonic  acid,  and  assign  the  use  of 
the  excretion  of  the  water,  which  escapes  by  the 
lungs,  with  more  precision.  He  supposes  the 
acid  to  be  evolved  in  the  course  of  the  circula- 
tion, by  that  "  process  of  reduction,"  by  which 
the  gelatin  of  the  animal  textures  is  formed 
from  the  albumen  of  the  blood ;  and  the  water 
to  be  given  off  chiefly  /rom  the  weak  albuminous 
matters  of  the  chyle,  and  to  be  an  essential  part 
of  the  "  process  of  completion,"  by  which  this 
is  converted  into  the  strong  albumen  of  the 
blood? 

2.  The  excretion   by   the  skin   is  chiefly 

See  IJridgewater  Treatise,  p.  524. 


watery  vapour;  the  escape  of  carbon,  or  carbonic 
acid,  by  this  outlet  appears  to  be  to  a  very  small 
amount,  and  to  be  very  variable.  In  the  sen- 
sible perspiration  or  sweat  there  is  an  excess  of 
lactic  acid,  a  small  quantity  of  the  same  animal 
and  saline  matters  as  are  contained  in  the  serum 
of  the  blood,  and  a  little  oily  or  fatty  matter, 
probably  from  the  sebaceous  glands ;  the  whole 
loss  by  this  excretion  in  the  human  adult  has 
been  stated  as  averaging  about  thirty  ounces  in 
the  day,  but  is  evidently  liable  to  very  great 
variety.  Many  experiments  prove  that  there  is 
much  less  compensating  absorption  by  this  tex- 
ture than  by  the  lungs. 

3.  The  excretions  by  the  bowels  are,  properly 
speaking,  only  those  parts  of  the  alvine  evacua- 
tions, which  are  secreted  within  the  body  itself, 
and  mixed  with  the  residue  of  the  food.  It  is 
probable  that  part  of  the  secretions  from  all 
parts  of  the  prima  viae  are  thus  excreted,  but 
the  only  one  of  which  it  has  been  ascertained 
that  it  is,  in  part  at  least,  destined  necessarily 
for  excretion,  is  the  bile.  It  is  certain  that  the 
peculiar  animal  matter  of  this  secretion,  (re- 
garded by  some  as  of  pretty  simple  and  by 
others  as  of  very  complicated  composition)  is 
never  found  in  the  healthy  state  in  the  lacteal 
vessels  or  thoracic  duct — that  it  is  found  in  full 
quantity  along  with  the  residue  of  the  aliments 
in  the  lower  intestines, — that  it  is  increased  in 
quantity  when  the  excretion  of  urine  is  sup- 
pressed in  animals  by  extirpation  of  the  kid- 
neys ;  and  again,  that  when  this  secretion  is  sup- 
pressed, the  urine  is  increased  and  altered  ;  and 
we  can  therefore  have  no  difficulty  about  regard- 
ing this  part  of  the  bile  as  strictly  an  excretion, 
notwithstanding  that  we  have  good  evidence, 
that  at  least  the  alkali  of  the  bile  is  of  use  in 
the  digestion  and  assimilation  of  the  food.  Of 
the  quantity  of  matter  strictly  excreted  from  the 
intestines  in  the  day  it  must  of  course  be  very 
difficult  to  judge.  The  chemical  elements  that 
escape  in  the  biliary  matter  must  be  chiefly 
carbon  and  hydrogen. 

4.  The  urine  is  the  most  complex  of  the  ex- 
cretions, particularly  as  to  saline  impregnation, 
containing  not  only  the  salts  which  are  detected 
in  the  blood,  but  a  portion  of  every  earthy  and 
saline  matter  that  can  be  found  in  any  part  of 
the  body,  besides  the  peculiar  and  highly  azo- 
tised  animal  matters,  lithic  acid  and  urea.  The 
average  quantity  of  urine  passed  in  twenty-four 
hours  may  be  about  forty  ounces,  but  is  very 
liable  to  variation,  particularly  by  temperature, 
being  generally  greater,  as  the  excretion  by  the 
skin  is  less.  The  quantity  of  solid  matter, 
animal,  earthy,  and  saline,  that  passes  off  in 
this  way  has  been  stated  at  about  fifteen  drachms 
on  an  average,  and  is  evidently  much  less  liable  to 
change,  the  density  of  urine,  in  the  healthy  state, 
always  diminishing  as  its  quantity  increases,  and 
vice  versa.  The  milk,  and  the  semen,  although 
destined  to  no  useful  office  in  the  system  in 
which  they  are  formed,  are  rather  to  be  called 
recrementilious  secretions  than  excretions.  Yet 
the  former  has  this  property  in  common  with 
excretions,  that  its  retention  within  the  body, 
when  the  conditions  of  its  formation  exist,  i^ 


150 


EXCRETION. 


hurtful.  The  menstrual  discharge  may  be 
regarded  as  strictly  an  excretion,  though  one 
which  is  required  only  in  the  human  species 
and  for  a  limited  time. 

Berzelius  stated  several  distinctions,  which 
he  thought  important,  between  the  excremen- 
titious  and  recrementitious  secretions  in  the 
animal  body,  particularly  that  the  former  are 
always  acid,  that  each  of  them  contains  more 
than  one  animal  matter,  and  that  their  salts  are 
more  numerous  and  varied  than  those  in  the 
blood,  while  the  latter  have  an  excess  of  alkali 
from  the  same  saline  ingredients  as  the  serum 
of  the  blood,  and  each  contains  only  a  single 
animal  principle,  substituted  for  the  albumen 
of  the  serum.  But  these  distinctions  are  cer- 
tainly inapplicable  in  several  instances,  and  the 
only  one  of  them  which  appears  to  be  a  general 
fact,  is  the  more  complex  saline  impregnation 
of  the  excreted  fluids. 

III.  It  is  unnecessary  to  dwell  on  the  well- 
known  injurious  effects,  on  the  animal  oeconomy, 
of  the  suppression  of  any  of  these  excretions. 
It  may,  indeed,  reasonably  be  doubted,  whether 
the  rapidly  fatal  effects  of  obstructing  the  ex- 
posure of  the  blood  to  the  air  at  the  lungs  are 
owing  to  the  retention  of  carbon,  or  carbonic 
acid ;  it  seems  much  more  probable  that  the 
cause  which  stops  the  circulation  at  the  lungs 
in  asphyxia,  is  the  suspension  of  the  absorption 
of  free  oxygen  into  the  blood,  rather  than  the 
suspension  of  the  evolution  of  carbon  or  car- 
bonic acid.  But  even  if  the  circulation  could 
be  maintained,  after  the  exposure  of  the  blood  to 
the  air  is  suspended,  we  know  that  the  carbonic 
acid  which  we  have  good  reason  to  believe 
would  soon  be  in  excess  in  the  blood,  would 
then  act  as  a  narcotic  poison.  Of  the  effects  of 
suspension  of  the  excretion  by  the  skin  we  can- 
not speak  with  certainty,  because  that  is  a  case 
which  probably  hardly  ever  occurs  ;  and  if  it 
were  to  occur,  the  lungs  and  kidneys  would 
probably  act  as  perfect  succedanea.  But  it  is 
worthy  of  notice  that  at  a  time  when  the  skin  is 
known  to  be  nearly  unfit  for  its  usual  functions 
— during  the  desquamation  that  succeeds  exan- 
the.matous  diseases,  and  especially  scarlatina, — 
the  lungs  and  the  kidneys,  on  which  an  unusual 
burden  may  thereby  be  supposed  to  be  thrown, 
are  remarkably  prone  to  disease.  The  effect  of 
suppression  of  the  excretion  of  urine  (i.  e.  of 
ischuria  renalis),  whether  occurring  as  a  disease 
in  man,  or  produced  by  extirpation  of  the  kid- 
neys in  animals,  is  uniformly  more  or  less  of 
febrile  symptoms  quickly  followed  by  coma 
and  death  ;  and  in  these  circumstances  it  is 
now  known,  that  the  urea  may  be  detected  in 
the  blood.  A  variety  of  morbid  affections,  and 
particularly  an  affection  of  the  nervous  system 
marked  by  inaptitude  for  muscular  or  mental 
exertion,  always  follows  the  obstruction  of  the 
excretion  of  bile,  and  absorption  of  bile  into 
the  blood  constituting  jaundice. 

There  are  a  few  cases  of  intense  jaundice 
which  terminate  in  coma  and  death  as  rapidly 
as  the  ischuria  renalis  does,  and  with  as  little 
morbid  appearance  in  the  brain  to  explain  this 
kind  of  fatal  termination  ;  and  in  several  such 


cases  the  remarkable  phenomenon  has  been 
observed  after  death,  that  the  bile-ducts  have 
been  pervious  and  empty.*  It  is  obvious,  that 
it  is  this  last  circumstance  only,  that  can 
make  a  case  of  jaundice  analogous  to  cases 
of  the  ischuria  renalis.  If  it  shall  appear 
to  be  a  general  fact,  that  the  cases  of  jaundice 
presenting  this  remarkable  appearance  on 
dissection  are  those  which  terminate  with 
unusual  rapidity  in  the  way  of  coma,  the 
analogy  will  appear  to  be  complete  ;  and  when 
such  cases  are  compared  with  those,  much 
more  frequently  occurring,  where  the  excretion 
of  bile  is  only  obstructed,  not  suppressed,  and 
where  months  frequently  elapse  without  any 
bad  symptom  occurring, — it  appears  a  reason- 
able conjecture,  that  the  retention  in  the  blood 
of  matters  destined  for  excretion,  is  more 
rapidly  and  certainly  injurious  than  the  re- 
absorption  of  matters  which  have  been  excreted 
from  the  blood  at  their  ordinary  outlet,  but  not 
expelled  from  the  body. 

Although  there  is  still  much  obscurity  in 
regard  to  the  intention  of  the  menstrual  dis- 
charge, yet  it  may  be  stated  as  a  general  fact, 
that  the  suppression  of  this  evacuation  is  more 
frequently  followed  by  injurious  effects  (particu- 
larly affections  of  the  nervous  system,  or  vica- 
rious hemorrhage)  than  the  stopping  of  an  equal 
amount  of  haemorrhage,  going  on  equally 
slowly,  would  be ;  so  that  the  general  principle 
applicable  to  other  excretions  is  exemplified 
here  likewise. 

IV.  The  next  question  in  regard  to  the  ex- 
cretions is,  in  what  manner  they  are  effected  ; 
and  on  this  question,  although  we  must  profess 
ignorance  in  the  last  result,  yet  it  is  instructive 
to  observe,  what  seems  now  to  be  well  ascer- 
tained, that  the  large  size,  and  apparently  com- 
plex structure,  of  several  of  the  organs  of  excre- 
tion, appear  to  be  no  part  of  the  contrivance 
for  the  formation  of  these  fluids  from  the  blood. 

It  is  stated  by  Cuvier,  as  the  result  of  a 
general  review  of  the  structure  of  glandular 
organs  in  different  classes  of  animals,  that  pro- 
ducts very  nearly  resembling  each  other,  and 
evidently  answering  the  same  ends,  are  formed 
in  organs  where  the  structure,  and  the  disposi- 
tion of  vessels  are  very  various ;  and  again, 
that  substances  the  most  widely  different  are 
formed  in  organs  that  are  in  these  respects  ex- 
tremely similar  ;f  and  that  this  should  be  the  case 
will  not  appear  surprising  when  we  consider 
the  result  of  the  most  minute  and  accurate 
observations  on  the  ultimate  structure  even  of 
those  secreting  organs,  which  form  substances 
the  most  dissimilar  to  the  general  nourishing 
fluid,  either  of  animals  or  vegetables.  "  Chaque 
cellule  de  la  structure  vegetale,"  says  De 
Candolle,  "  peut  etre  considered  comme  une 
vesicule  organique  et  vivante,  qui  est  entouree, 
ou  de  cavites  dans  lesquelles  abordent  des 
liquides,  ou  de  cellules  remplies  elles-memes  de 

*  See  Marsh  in  Dublin  Hospital  Reports,  vol.  iii. 
Two  cases  of  exactly  the  same  description  have  oc- 
curred within  these  few  years  in  the  Edinburgh 
Clinical  wards. 

t  Lecons  d'Anat.  Comp.  t.  v.  p.  214. 


EXCRETION. 


151 


liquides.  Cette  vesicule,  par  sa  vitalite  propre, 
absorbe  une  partie  du  fluide  qui  l'entoure ; 
ce  fluide  est  ou  de  l'eau  presque  pure,  et  alors 
elle  en  est  simplement  impregnee  et  lubrifiee  ; 
ou  de  l'eau  plus  ou  moins  chargee  de  cette 
matiere  gommeuse,  elaboree  dans  les  feuilles, 
et  d'autres  matieres  alimentaires  qui  peuvent 
se  trouver  portees  avec  la  seve  dans  les  diverses 
parties.  Lit  vesicule  qui  Pa  absorbte  lui  J'ait 
subir  une  action  determin'ce  d'apres  sa  propre 
nature,  et  cette  action  modifie  les  materiaux 
contenus  dans  la  cellule,  de  maniere  a  en  faire, 
ou  l'une  des  matieres  communes  que  nous 
avons  considerees,  ou  l'une  des  matieres  que 
nous  aurons  bientot  a  examiner,  telles  que 
les  huiles  volatiles,  les  resines,  &c.  Certains 
vaisseaux  analogues  a  la  nature  des  cellules 
jouent  le  meme  role  sous  ce  rapport.  Les 
matieres  ainsi  localement  elaborees  peuvent,  ou 
rester  dans  les  cellules  ou  les  vaisseaux  qui 
leur  ont  donne  naissance,  ou  s'extravaser  au 
dehors  et  donner  lieu,  soit  a  des  excretions,  soit 
a  des  transports  des  matieres  d'une  partie  a 
1 'autre  du  tissu."* 

The  description  given  by  Dutrochet  of  the 
act  of  secretion  as  it  may  almost  be  detected 
in  the  glands  of  the  lower  classes  of  animals, 
is  exactly  similar.  "  Entre  les  vesicules  qui 
composent  le  tissu  organique  des  animaux 
rampentles  vaisseaux  sanguins,  chez  les  animaux 
a  circulation  :  ces  vesicules  sont  appliquees 
sur  les  parois  des  vaisseaux ;  et  il  est  certain 
que  la  cavite  des  vesicules  ne  communique 
point  immediatement  avec  la  cavite  des  vais- 
seaux, puisque  le  meme  fluide  n'existe  point 
dans  leurs  cavites.  Ce  fait  est  tres  facile  a 
verifier,  en  examinant  au  microscope  le  tissu 
d'un  organe  secretive  chez  un  mollusque  gas- 
teropode,  celui  de  la  foie  par  example  :  on 
voit  toutes  les  vesicules  de  cet  organe  remplies 
par  la  bile,  que  Ton  distingue  a  sa  couleur, 
tandisque  les  vaisseaux  sanguins  qui  cotoient 
ces  vesicules  n'ont  que  la  diaphaniete  que  leur 
donne  l'etat  incolore  du  sang  qui  les  remplit. 
Ainsi,  les  vaisseaux  sanguins  n'existent  que 
comme  des  moyens  d'irrigation  pour  les  vesi- 
cules qu'ils  cotoient,  et  ce  n'est  peut-etre  que 
par  filtration  que  le  fluide  sanguin  penetre,  en 
si  modifiant,  jusque  dans  ces  vesicules  elemen- 
taires.  Le  systeme  sanguin,  considere  dans 
son  entier,  forme  une  cavite  sans  issue,  dans 
laquelle  rien  ne  peut  entrer,  et  de  laquelle  rien 
ne  peut  sortir,  autrement  que  par  filtration."f 

Any  one  who  is  acquainted  with  the  elabo- 
rate "  Vasorum  Lymphaticorum  Historia"  of 
Mascagni,  will  recognize  the  perfect  accordance 
of  this  statement  with  the  result  of  his  careful 
and  minute  investigation  of  the  structure  of  the 
secreting  organs  in  the  higher  animals.} 

We  may  consider,  then,  the  act  of  secretion, 

en  derniere  analyse,"  as  consisting  simply  in 

*  Physiol.  Vegetale,  p.  215. 
t  L'agent  immediat  du  mouvement  vital  devoile, 
&c.  p.  192. 

J  It  must  Dot  be  considered  as  ascertained,  that 
the  files  or  tracks  of  globules  of  blood  seen  under 
the  microscope,  and  usually  called  capillaries, 
have  really,  in  all  animals,  aud  all  parts  of  these, 
vascular  coats.     It  seems  pretty  certain,  that  in 


the  passage  of  certain  portions  of  a  compound 
fluid  through  a  thin  living  membrane,  and  the 
exclusion  of  others;  or,  according  to  the  for- 
tunate expression  of  Dutrochet,  as  a  chemical 
filtration.  "  All  that  is  necessary  for  any 
kind  of  secretion  in  a  living  animal,"  says  Mr. 
Mayo,  "  is  a  vascular  membrane,  and  all  the 
arrangements  of  the  glands  appear  to  be  merely 
contrivances  for  conveniently  packing  a  great 
extent  of  such  a  surface  in  a  small  compass." 
And  if  we  are  asked,  to  what  cause  we  can 
ascribe  this  escape  of  certain  matters  from  the 
circulating  fluid  through  one  portion  of  mem- 
brane, and  of  others  through  another,  we  can 
only  answer,  in  the  words  of  this  last  author, 
that  it  depends  on  the  exercise  of  certain  "  vital 
affinities,''  peculiar  to  the  living  stale,  and  the 
existence  of  which  will  always  be  an  ultimate 
fact  in  Physiology,  although  we  may  attain  to 
a  knowledge  of  the  laws  according  to  which 
they  operate. 

V.  One  principle  may  already  be  laid  down, 
almost  with  certainty,  as  to  the  exercise  of  these 
powers  in  the  present  instance,  viz.  that  the 
peculiar  matters  characterizing  the  excretions 
are  not  actually/brmerf  from  the  blood  at  the 
parts  where  they  appear,  but  only  separated 
from  the  blood  at  these  parts, — their  formation, 
if  not  actually  completed,  having  been  at  least 
considerably  advanced,  in  the  blood  itself 
which  reaches  these  parts.  Of  this  we  are 
well  assured,  chiefly  by  the  following  facts. 

1.  The  experiments  already  mentioned,  first 
made  by  Prevost  and  Dumas,  have  proved 
that  within  a  short  time  after  the  extirpation  of 
the  kidneys  in  animals,  urea  may  be  detected 
in  the  blood,  showing  clearly  that  the  existence 
of  these  glands  is  not  necessary  to  the  forma- 
tion of  this  very  peculiar  excrementitious  matter, 
and  giving  us  reason  to  conjecture  that  the 
office  of  the  kidneys  is,  not  to  form  the  urea, 
but  to  attract  it  out  of  the  blood  as  fast  as  it  is 
formed  there.  The  same  existence  of  urea  in 
the  blood  has  been  ascertained  in  the  human 
body,  both  in  cases  of  diseased  kidneys,  when 
the  excretion  there  was  much  impeded,  and  in 
cases  of  malignant  cholera,  when  the  excretion 
was  suppressed.  The  cases  of  rapidly  fatal  jaun- 
dice al  ready  mentioned,  where  the  bile-ducts  were 
pervious  and  empty,  would  seem  to  have  been 
cases  where  the  peculiar  matter  of  the  bile  has 
been  in  like  manner  formed  in  the  blood, 
without  finding  the  usual  vent  at  the  liver. 
And  it  will  appear  under  the  head  of  Respira- 
tion, particularly  from  the  experiments  of  Dr. 
Edwards,  and  of  Collard  de  Martigny,  that 
there  is  good  reason  to  believe  the  carbonic  acid 
of  expired  air  to  be  formed  in  the  course  of  the 
circulation,  and  only  exchanged  for  oxygen  at 
the  lungs. 

2.  There  are  various  instances  in  disease,  of 
substances  generally  found  in  the  secretions  of 
certain  glands  only,  being  deposited  in  situa- 
tions quite  unusual,  and  where  no  texture 
similar  to  these  glands  exists;  e.  g.  cholesterine, 

many  cases  they  are  only  lines  or  membranes,  or 
channels  in  a  solid  parenchyma  ;  but  still  the  obser- 
vation in  the  text  applies  strictly  to  the  escape  of 
any  particles  of  the  circulating  fluid  from  them. 


152 


EXCRETION. 


which  in  the  natural  state  is  found  only  in  the 
bile,  has  been  found  deposited  in  diseased 
structures  in  the  brain,  kidneys,  pelvis,  scro- 
tum, &c. ;  and  lithic  acid,  naturally  existing 
only  in  the  urine,  is  deposited  in  cases  of  chalk- 
stone  in  the  textures  immediately  surrounding 
the  joints  of  the  fingers  and  toes.  It  seems  to 
be  nearly  in  like  manner  that  purulent  matter, 
when  mixed  in  unusual  quantity  with  the 
blood,  as  by  inflammation  of  a  vein,  is  fre- 
quently deposited  in  individual  parts  of  the 
body,  with  little  or  none  of  the  usual  sym- 
ptoms, or  of  the  other  accompaniments,  of  in- 
flammation at  these  parts. 

3.  There  are  a  considerable  number  of  cases 
recorded  on  unexceptionable  evidence,  where 
excretions  have  passed  off  per  aliena  cola,  i.  e. 
by  organs  which  in  the  natural  state  yield  no 
such  products,  and  the  structure  of  which  is 
widely  different  from  that  of  the  glands  where 
they  are  usually  secreted.  This  has  been  most 
frequently  observed  of  the  milk  and  of  the 
urine,  and  of  the  latter,  both  in  cases  where 
the  secretion  at  the  kidneys  had  been  sup- 
pressed, and  in  cases  where  its  discharge  by 
the  urinary  passages  has  been  obstructed,  so 
as  to  occasion  its  re-absorption.  In  both  cases 
it  is  obvious  that  the  peculiar  matter  of  this 
excretion  must  have  been  first  mixed  generally 
with  the  blood,  and  then  deposited  in  indivi- 
dual parts  of  the  system,  widely  different  as  well 
as  distant  from  those  where  it  usually  appears. 

In  cases  of  this  kind  collected  by  Haller,* 
the  vicarious  discharge  of  urine  is  stated  to 
have  occurred  from  the  skin,  from  the  stomach, 
from  the  intestines,  and  from  the  nipples;  and 
in  cases  recorded  by  Dr.  Arnold  and  Dr.  Sen- 
ter  in  America,  it  is  stated  to  have  been  passed  by 
vomiting,  by  stool,  from  the  nose  and  from  the 
mammae,  as  well  as  other  parts.f  Both  in 
cases  given  by  Haller,  and  in  one  recorded  in 
Magendie's  Journal  de  Physiologie,  (vol.  vii.) 
milk  is  stated  to  have  been  evacuated  in  quan- 
tity from  pustules  that  formed  on  the  thigh  ; 
and  among  the  former  are  instances  of  its  hav- 
ing passed  off  from  the  salivary  glands,  the 
kidneys,  and  the  uterus.  Such  statements 
were  formerly  considered  as  fabulous,  but  since 
the  facts  already  mentioned  (and  particularly 
the  appearance  of  urea  in  the  blood  after  ex- 
tirpation of  the  kidneys)  have  been  ascertained, 
this  scepticism  seems  no  longer  reasonable. 

It  must  be  here  observed,  that  the  healthy 
blood  is  easily  shown  to  contain  in  itself  mat- 
ters more  nearly  akin  to  all  the  solid  textures 
and  to  the  other  secreted  fluids  of  the  body, 
than  to  the  bile  and  the  urine ;  and  hence,  if 
we  are  satisfied  that  the  elaboration  of  these 
latter  fluids  is  effected  in  the  blood  itself,  and 
does  not  essentially  require  any  special  action 
of  the  organs  in  which  they  usually  appear, 
there  can  be  little  hesitation  about  extending 
this  inference  to  other  acts  of  secretion  and 
to  nutrition.  It  appears,  therefore,  at  least 
highly  probable,  that  the  whole  processes  of  as- 
similation and  elaboration  of  the  fluids  in  the 

*  Elem.  Phys.  lib.  vii.  ch.  1. 

t  London  Med.  and  Phys.  Journal,  1828. 


living  body  are  carried  on,  as  other  chemical 
changes  on  fluids  are,  in  the  interior  of  these 
fluids  themselves,  and  that  the  solids  of  the 
body  are  concerned  in  these  changes  only  in 
two  ways  :  first,  by  securing  the  complete  sub- 
division and  intimate  intermixture  of  the  fluids 
necessary  to  their  chemical  changes ;  and  second- 
ly, by  determining  the  parts  of  the  body  where 
peculiar  matters,  already  existing  in  the  blood, 
shall  be  deposited  from  it,  or  attracted  out  of  it. 

VI.  We  may  next  enquire,  what  is  the  most 
probable  original  source  of  the  matters  which 
are  thrown  out  of  the  body  in  the  way  of  ex- 
cretion. As  it  is  generally  believed,  and  on 
strong  grounds,  that  the  solid  textures,  as  well 
as  prepared  fluids  of  the  body,  are  liable  to 
continual  decay  and  renovation,  it  has  long  been 
the  general  belief,  that  the  materials  for  the  ex- 
cretions are  supplied  chiefly  from  those  sub- 
stances which  have  formed  part  of  the  textures, 
and,  after  fulfilling  their  office  there,  have  been 
taken  back  into  the  circulation  with  a  view  to 
their  discharge  from  the  body.  And  it  has 
been  conjectured,  certainly  with  much  probabi- 
lity, by  Berzelius  and  by  Autenrieth,  that  the 
animal  matters  thus  mixed  with  the  blood  on 
their  way  to  the  excretories,  are  distinguishable 
from  the  albuminous  or  nutritious  parts  of  the 
blood,  by  their  solubility  both  in  hot  and  cold 
water,  and  constitute  the  animal  matter  of  the 
serosity,  or  uncoagulable  animal  matter  of  the 
blood.  This  is  supported  by  the  observation, 
that,  when  the  kidneys  are  extirpated,  this 
part  of  the  blood  is  first  observed  to  increase 
in  amount,  and  afterwards  it  is  here  that  the 
urea  is  detected.*  And  the  connexion  of 
the  excretions  with  absorption  from  all  parts  of 
the  body  seems  farther  illustrated  by  the  pheno- 
mena of  diabetes,  which  may  be  held  to  be  the 
disease  in  which  there  is  the  strongest  evidence 
of  increased  absorption  in  all  parts  of  the  body, 
from  the  rapid  digestion,  the  rapid  recurrence 
of  thirst  after  drinking,  the  dryness  of  the  sur- 
face, and  the  progressive  emaciation  notwith- 
standing the  excessive  amount  of  ingesta  ;  and 
in  which  the  quantity  of  the  urine  is  often  ten 
times,  and  the  solid  contents  of  the  urine  often 
twenty  times,  the  average  quantity  in  health.f 

But  it  should  not  be  too  hastily  concluded, 
that  all  the  solid  constituents  of  the  animal  body 
are  liable  to  continual  absorption  and  renova- 
tion. The  permanence  of  coloured  marks  on 
the  skin,  noticed  by  Magendie,  is  sufficient 
evidence,  that,  in  some  of  the  textures,  any  such 
change  must  go  on  very  slowly  ;  and  some  of 
the  best  observers  doubt  whether  any  such  pro- 
cess of  alternate  deposition  and  absorption  takes 
place  in  vegetables,  in  which,  nevertheless,  as 
we  have  seen,  excretion  is  a  necessary  process. 

*  Provost  ct  Dumas  in  Ann.  de  Chimie,  t.  xxiii. 
p.  97. 

t  The  change  of  nature  of  the  animal  part  of 
this  solid  matter,  (viz.  the  disappearance  of  part  of 
the  urea,  and  substitution  of  an  excessive  quantity 
of  sugar,)  is  evidently  connected  with  the  singular 
fact  ascertained  by  Dr.  Prout,  that  sugar  differs 
from  urea  simply  in  containing  no  azote,  and  a  dou- 
hle  quantity  of  carbon  and  oxygen :  a  discovery 
which  will,  probably,  acquire  a  greatly  increased 
importance  in  the  progress  of  organic  chemistry. 


EXCRETION. 


153 


Dr.  Prout  has  lately  stated  strong  reasons  for 
thinking,  that  great  part  of  the  contents  of  the 
lymphatic  vessels  are  not  excrementitious,  but 
destined  for  useful  purposes  in  the  animal  eco- 
nomy; remarking  particularly  on  the  way  in 
which  hybernating  animals  appear  to  be  nou- 
rished by  absorption  of  their  own  Jut* 

And  it  is  obviously  possible,  that  the  excre- 
tions may  be  required  to  purify  the  blood  of 
matters  taken  in  from  without,  or  evolved  in 
the  coui^se  of  the  circulation  and  its  abundant 
changes,  as  well  as  to  purify  it  of  what  has 
been  absorbed  from  the  system  itself.  Now 
that  we  know,  that  great  part  of  the  ingesta  into 
the  stomach  are  taken  up  by  the  veins,  and  pass 
through  the  liver  on  their  way  to  the  heart ;  and, 
likewise,  that  the  venous  blood  is  the  chief 
source  of  the  excretions  of  bile,  it  seems  pro- 
bable, that  one  important  use  of  this  excretion 
is,  to  subject  a  part  of  the  ingesta  to  a  second 
filtration,  or  rejection  of  part  of  their  ingre- 
dients, subsidiary  to  that  which  they  undergo  in 
the  primae  via?.  This  may  also  be  probably  one 
principal  reason  why  the  great  mass  of  the  chyle, 
and  other  products  of  absorption  in  the  body, 
should  be  mixed  with  the  blood  just  before  its 
concentration  at  the  heart,  and  subsequent  dif- 
fusion through  the  lungs ;  and  thus  participate 
in  a  purification,  by  the  rejection  of  water  and 
carbonic  acid,  before  they  are  applied  to  the 
purposes  of  nutrition.  We  know,  that  in  birds, 
reptiles,  and  fishes,  there  is  a  venous  circulation 
similar  to  that  of  the  vena  porta?,  through  the 
substance  of  the  kidneys,  of  most  of  the  blood 
coming  from  the  lower  half  of  the  body ;  a 
part  of  the  ingredients  of  that  blood  will,  there- 
fore, be  evolved  with  the  urine;  and,  in  the 
case  of  the  reptiles,  it  has  been  lately  ascertained, 
that  this  venous  blood  receives,  before  entering 
the  kidneys,  the  contents  of  numerous  and  large 
lymphatics.f 

At  all  events,  if  we  are  right  in  supposing, 
that,  in  the  higher  animals,  all  the  great  chemi- 
cal changes  which  are  wrought  on  the  blood, 
even  the  formation  of  the  excretions,  are  effected 
during  its  circulation  in  the  bloodvessels  them- 
selves, we  can  thereby  acquire  a  general  notion 
of  the  intention  of  several  contrivances,  the  use 
of  which  is  otherwise  very  obscure.  We  can 
understand,  that  the  object  of  the  concentration 
of  the  blood  at  the  heart  may  be  not  merely 
mechanical,  but,  partly,  also  chemical ;  and  we 
can  see  the  intention  of  the  heart  being  so  ad- 
mirably adapted,  by  the  articulated  structure  of 
its  internal  surfaces,  not  only  to  receive  and 
propel,  but  also  most  effectually  to  intermix,  all 
the  component  particles  of  the  blood,  both  be- 
fore and  after  its  exposure  to  the  air  ;  the  most 
perfect  illustration  of  which  power  of  the  heart 
is  afforded  by  the  effect  it  produces  on  any  com- 
pressible and  elastic  fluid  which  is  received  in 
a  mass  of  any  considerable  volume  into  its  cavi- 
ties, and  which  is  necessarily  subdivided  into  so 
many  minute  globules,  and  compressed  in  so 
many  directions,  that  it  cannot  escape  from  the 
heart,  and  so  stops  the  circulation. 

*  Bridgcwater  Treatise,  p.  515,  et  seq. 
t  M'uller,  in  Phil.  Transactions,  1833. 


Again,  when  we  attend  to  the  manner  in 
which  substances  foreign  to  the  circulation  are 
absorbed  into  it,  whether  from  the  system  itself, 
or  from  without,  we  see  a  great  deal  of  contri- 
vance, evidently  adapted,  andprobably  intended, 
to  secure  the  most  gradual  introduction,  and  the 
most  perfect  intermixture  possible,  and  to  allow 
the  escape  of  certain  parts  of  the  compound 
fluid  formed.  Thus  of  the  contents  of  the 
primae  via?,  part  are  absorbed  into  the  veins,  and 
sent  through  the  capillaries  of  the  liver  and 
those  of  the  lungs,  (both  admitting  of  excretion,) 
before  they  are  admitted  into  the  arteries. 
What  is  taken  up  by  the  lacteals  has  already 
undergone  much  elaboration  by  living  fluids ; 
this  portion  passes  through  the  mesenteric  glands, 
and  is,  probably,  so  far  intermixed  with  the 
blood  there,  and  partly  received  into  the  veins 
passing  from  them  to  the  liver;*  and  the  rest  is 
mixed  with  much  matter  flowing  from  other 
parts  of  the  system  by  the  lymphatics;  and, 
according  to  the  views  of  Dr.  Proutt  as  to  the 
nature  of  absorption,  is  so  far  assimilated  by 
this  mixture  also,  before  it  is  poured  into  the 
great  veins  in  the  state  of  chyle,  to  undergo  the 
thorough  agitation  at  both  sides  of  the  heart, 
and  to  participate  in  the  changes  at  the  lungs. 
What  is  absorbed  from  other  parts  of  the  body 
seems  to  be  partly  taken  up  by  the  veins,  partly 
also  by  lymphatics  which  immediately  convey 
it  into  adjacent  veins;  the  remainder  passes 
through  lymphatic  glands,  and  is  there  pretty 
certainly  subjected  to  an  intermixture  and  an 
interchange  of  particles  with  blood;  after 
which  it  has  necessarily  much  further  adm'ix- 
ture,  and  two  thorough  agitations  at  the  heart, 
as  well  as  the  exposure  at  the  lungs,  to  undergo, 
before  arriving  at  the  left  side  of  the  heart. 

In  those  of  the  vertebrated  animals  which 
have  no  lymphatic  glands,  the  thorough  inter- 
mixture of  the  fluids  contained  in  the  lymphatic 
vessels  is  provided  for  by  numerous  plexuses,}: 
and,  in  the  case  of  reptiles,  by  distinct  lympha- 
tic hearts  communicating  with  veins  ;§  and  we 
are  sure,  that  much  of  the  matters  absorbed  in 
these  animals,  whether  by  veins  or  lymphatics, 
passes  through  the  capillaries  of  the  kidneys  or 
liver,  as  well  as  the  lungs,  before  reaching  the 
arteries. 

When  we  see  so  much  contrivance,  evidently 
adapted  for  giving  every  facility  to  the  gradual 
operation  of  the  vital  affinities  subsisting  among 
the  constituents  of  the  blood,  before  it  reaches 
the  scene  of  any  of  the  acts  of  nutrition,  secre- 
tion, or  excretion,  we  cannot  be  surprised  to 
find,  that  these  acts  themselves  should  appear 
to  be  so  simple  as  the  observations  already 
quoted  would  seem  to  indicate. 

It  must  be  admitted,  that  if  we  consider  these 
contrivances  in  the  higher  animals  as  important 
agents  in  the  elaboration  of  the  blood,  and  con- 
sequent formation  of  the  textures  and  prepared 
fluids  of  the  body,  there  is  a  difficulty  in  under- 
standing how  these  objects  can  be  accomplished 

*  Tiedemann  et  Gmelin,  Recherches,  &c. 
t  Bridgewater  Treatise,  ubi  stipra. 
t  Cuvier,  Lemons,  &c.  t.  iv.  p.  98. 
§  Miiller,  ubi  supra. 


154 


EXTREMITY. 


in  the  lowest  classes,  particularly  the  insects 
and  zoophyta,  where  the  nourishment  of  various 
textures,  and  formation  of  secretions  and  excre- 
tions, has  been  thought  to  be  merely  in  the  way 
of  imbibition  from  a  central  cavity.*  But  it  is  to 
be  observed,  that  in  several  of  these  tribes,  in 
insects,  and  even  in  the  infusory  animals,  recent 
observations  have  disclosed  a  much  more  com- 
plex apparatus  for  the  movement  of  the  fluids, 
than  was  previously  suspected.  And,  in  regard 
to  the  lowest  zoophyta,  it  may  be  said  in  general, 
that  if  there  is  little  apparent  provision  for  the 
elaboration  of  the  fluids,  there  is  also  little 
occasion  for  it,— first,  because  there  is  little 
variety  of  textures  to  be  nourished,  and 
secondly,  because  the  simplicity  of  their 
structure  is  such,  that  all  the  particles  of  their 
nourishing  fluid, — -admitted  into  a  central 
cavity,  flowing  thence  towards  their  surface,  and 
acted  on  by  the  air  at  all  parts  of  that  surface, — 
are  similarly  situate  in  regard  to  all  the  agents 
by  which  they  can  be  affected,  and  must  be 
equally  fitted  for  the  changes  which  the  vital 
affinities  there  acting  on  them  can  produce,  so 
that  the  same  necessity  for  gradual  intermixture, 
and  repeated  agitation,  of  heterogeneous  mate- 
rials, does  not  probably  exist  in  them,  as  in 
the  animals  of  more  complex  structure.  The 
analogy  of  their  economy,  therefore,  is  not  a 
serious  objection  to  the  inference  we  have 
drawn  from  so  many  other  facts,  as  to  the 
numerous  changes  which  are  wrought  in  the 
blood  of  the  higher  animals,  while  circulating 
in  the  vessels,  and  as  to  the  function  of  excre- 
tion being  a  necessary  accompaniment  of  the 
assimilation  of  aliment,  and  nutrition  of  tex- 
tures, even  independently  of  their  renovation  by 
processes  of  ultimate  deposition  and  absorption . 

C  W.  P.  Alison.) 

EXTREMITY,  (in  human  anatomy),  mem- 
brunt,  artus;  Gr.  ^eXo;,  zaXov ;  Fr.  extremit't, 
membre  ;  Germ.  Gliedmassen  ;  Ital.  membro. 
This  term  is  used  to  denote  certain  appendages 
most  manifest  in  the  vertebrated  classes  of 
animals,  employed  as  instruments  of  prehen- 
sion, or  support,  or  motion,  also  occasionally 
employed  for  other  purposes  sufficiently  in- 
dicated by  the  habits  of  the  animal.  In  fa- 
miliar language  we  apply  the  word,  limb, 
synonymously,  and  the  superior  and  inferior 
limbs  of  man,  or  the  anterior  and  posterior  ones 
of  the  Mammiferous  Quadrupeds,  are  the  best 
examples  by  which  we  can  illustrate  our  de- 
finition. When  these  appendages  exist  in  their 
complete  number,  i.  e.  four,  they  are  distin- 
guished either  by  the  appellatives  already 
mentioned,  anterior  and  posterior,  or  superior 
and  inferior,  or  more  precisely  pectoral,  and 
pelvic  or  ventral,  or  again  atlantal  and  sacral. 

In  Fishes  we  find  that  in  most  instances  the 
anterior  limbs  (pectoral  fins)  are  larger  than  the 
posterior  (ventral  fins) :  and  sometimes  the 
posterior  are  absent  altogether,  as  in  the  com- 
mon eel.  In  Fishes  we  look  for  the  simplest 
form  of  the  skeleton  of  the  more  highly  de- 
veloped limbs  in  Man  and  Mammalia :  and 

*  Cuvicr,  Le^ns,  &c.  27. 


here  we  find,  more  or  less  obviously  in  differ- 
ent instances,  the  same  elements  which  sub- 
sequently appear  in  a  more  distinct  and  com- 
plete form.  Thus,  in  the  case  of  the  Lophius 
piscatorius,  we  find  very  distinctly  the  scapula 
and  clavicle  forming  the  bond  of  connection 
of  the  other  bones  of  the  limb  to  the  trunk. 
We  can  also  recognize  the  radius  and  ulna, 
what  seems  to  be  a  very  rudimentary  humerus, 
and  the  bones  of  the  carpus,  as  well  as  the 
phalanges,  which  generally  greatly  exceed  in 
number  any  arrangement  that  is  to  be  found 
in  the  higher  classes.  The  ventral  fins,  how- 
ever, the  analogues  of  the  posterior  extremities, 
are  not  so  developed :  while  bones  analogous  to 
the  phalanges  of  the  feet  are  found  in  it,  we  meet 
no  trace  of  the  femur,  tibia,  or  fibula 

In  all  the  other  Vertebrata  we  find  the  an- 
terior and  posterior  extremities  developed  on 
a  plan  similar  to  that  in  man,  with  such  vari- 
ations as  the  manner  of  life  of  the  animal 
requires.  We  must,  however,  notice  an  excep- 
tion in  the  case  of  serpents  and  Cetacea.  In 
the  former  there  are  no  limbs,  or  at  least  the 
merest  trace  of  them ;  in  the  latter  the  pos- 
terior are  absent,  although  the  anterior  exhibit 
very  perfectly  all  the  elements  of  the  human 
upper  extremity. 

We  propose  to  devote  the  present  article  to 
the  detail  of  the  descriptive  anatomy  of  the 
osseous  system  of  the  extremities  in  Man, 
in  whom,  by  reason  of  his  erect  attitude,  the 
terms  superior  and  inferior  are  substituted  for 
anterior  and  posterior,  as  applied  to  the  ex- 
tremities of  the  lower  animals. 

Superior  extremity. — The  superior  extremity 
is  connected  to  the  trunk  through  the  medium 
of  two  bones,  which,  as  being  intimately  con- 
nected with  the  motions  of  the  limb,  first  de- 
mand attention.  These  bones  are  the  clavicle 
and  scapula,  and  are  commonly  called  the 
bones  of  the  shoulder. 

Clavicle  (from  clavis,  a  key;)  collar-bone  ; 
syn.  ligula,  jugulum,  os furcate;  Germ.  Schlus- 
selbein.  This  bone  is  situated  at  the  upper 
and  anterior  part  of  the  thorax,  and  forms  the 
anterior  part  of  the  shoulder :  its  direction  is 
from  within  outwards,  so  that  its  external  end, 
which  is  articulated  with  the  scapula,  is  pos- 
terior, and  on  a  plane  superior  to  its  internal 
end,  which  is  articulated  with  the  sternum. 
It  thus  constitutes  the  key  to  the  bony  arch 
formed  at  the  shoulder,  and  hence  its  integrity 
is  especially  necessary  to  the  integrity  of  the 
motions  of  the  shoulder. 

The  clavicle  is  a  long  bone,  cylindrical,  and 
so  curved  as  to  resemble  the  italic  f  placed 
horizontally.  Its  internal  extremity  is  thick 
and  rounded,  while  its  external  one  is  flat- 
tened ;  of  its  two  curves  one  is  internal,  with 
its  convexity  directed  forwards ;  the  other  ex- 
ternal, with  its  convexity  directed  backwards. 

The  internal  extremity,  also  called  sternal, 
is  formed  by  a  gradual  expansion  of  the  shaft 
of  the  bone,  which,  however,  still  preserves 
the  general  cylindrical  form,  but  is  flattened  a 
little  on  its  superior  surface :  in  size  this  ex- 
ceeds all  other  parts  of  the  bone.  The  inner 
surface  of  this  extremity  of  the  clavicle  is 


EXTREMITY. 


155 


destined  for  articulation  with  the  sternum,  and 
accordingly  we  find  on  it  a  considerable  arti- 
cular facet,  which  is  convex  from  above  down- 
wards, and  concave  from  before  backwards. 
The  outline  of  this  surface  is  triangular,  and 
each  angle  is  easily  distinguishable  by  the 
degree  of  its  prominence :  thus,  one  angle  is 
situated  anteriorly  and  inferiorly,  it  is  the  least 
prominent ;  a  second  is  posterior  and  inferior, 
it  is  the  most  prominent;  and  the  third  is  su- 
perior, and  may  easily  be  felt  under  the  inte- 
guments in  the  different  motions  of  the  bone. 

The  external  or  acromial  end  of  the  clavicle 
is  at  once  distinguished  by  its  flattened  appear- 
ance; it  is  flattened  on  its  superior  and  in- 
ferior surfaces.  At  its  extremity  we  find  an 
elliptical  articular  surface  adapted  to  a  similar 
one  upon  the  acromion  process  ;  this  surface  is 
nearly  plane,  its  long  axis  is  directed  horizon- 
tally from  before  backwards. 

The  body  or  shaft  of  the  bone  presents  se- 
veral points  deserving  of  notice.  The  superior 
surface  is  smooth  and  rounded,  expanding  to- 
wards the  sternal  end,  where  it  affords  attach- 
ment to  the  clavicular  portion  of  the  sterno- 
mastoid  muscle.  It  expands  likewise  towards 
the  acromial  end,  but  loses  the  cylindrical 
form  and  becomes  flattened :  the  central  part 
is  the  most  contracted  and  the  most  cylindrical; 
here  the  bone  is  almost  subcutaneous,  being  co- 
vered only  by  the  common  integument,  some 
fibres  of  the  platysma,  and  crossed  by  the 
supra-clavicular  filaments  from  the  cervical 
plexus  of  nerves. 

On  the  inferior  surface  of  the  clavicle  we 
notice  towards  its  sternal  end  a  rough  surface 
for  the  insertion  of  the  costo-clavicular  or  rhom- 
boid ligament :  external  to  this  and  extending 
outwards  is  a  superficial  excavation  along  the 
inferior  surface  of  the  bone,  which  lodges  the 
subclavius  muscle.  This  groove  terminates  at 
the  commencement  of  the  external  fourth  of 
the  bone,  where  we  notice  a  rough  and  promi- 
nent surface  for  the  insertion  of  the  coraco-cla- 
vicular  or  conoid  and  trapezoid  ligaments;  in 
the  articulated  skeleton  this  surface  corresponds 
to  the  root  of  the  coracoid  process,  immediately 
over  which  it  lies.  On  the  inferior  surface, 
near  its  middle,  is  the  orifice  of  the  canal  for 
the  transmission  of  the  nutritious  artery,  the 
direction  of  which  is  outwards. 

The  anterior  edge  is  thicker  and  more  rounded 
towards  the  inner  than  towards  the  outer  end, 
where  it  partakes  of  the  general  flattened  ap- 
pearance of  the  bone  at  that  part;  in  the  former 
situation  it  affords  attachment  to  the  pectoralis 
major  muscle — in  the  latter  to  the  deltoid.  The 
two  internal  thirds  of  this  edge  are  convex,  its 
external  third  is  concave. 

The  posterior  edge  is  smooth  and  thin  upon 
its  two  internal  thirds,  thicker  and  rougher  at 
its  external  third,  where  the  trapezius  muscle  is 
inserted  into  it;  in  the  former  situation  this 
edge  is  convex,  in  the  latter  it  is  concave.  The 
relations  of  the  clavicle  in  this  situation  are  in- 
teresting :  it  forms  the  anterior  boundary  of  a 
space  somewhat  triangular  in  form,  through 
which  a  communication  is  formed  between  the 
axilla  and  the  neck.    The  posterior  boundary 


of  this  opening  is  formed  by  the  superior 
border  of  the  scapula,  and  the  internal  by  the 
inferior  vertebra  of  the  cervical  region  of  the 
spine,  while  the  first  rib  constitutes  a  sort  of 
floor,  over  which  pass  the  various  vessels,  nerves, 
and  other  parts  which  enter  the  cavity  of  the 
axilla.  The  anterior  third  of  the  first  rib  passes 
beneath  the  sternal  end  of  the  clavicle,  but  its 
two  posterior  thirds  lie  on  a  plane  superior  to 
it.  Consequently  we  find  that  the  cone  of  the 
pleura  passes  up  behind  this  end  of  the  clavicle 
so  as  to  be  on  a  level  with  it,  hence  the  so- 
noriety  elicited  by  percussion  of  the  clavicle, 
and  hence  likewise  the  possibility  in  many 
instances,  where  embonpoint  does  not  interfere, 
of  hearing  the  respiratory  murmur  in  the  supra- 
clavicular region. 

The  great  importance  of  the  clavicle  in  the 
motions  of  the  upper  extremity  is  rendered 
abundantly  evident  by  observing  how  com- 
pletely synchronous  are  its  movements  with 
even  the  slightest  change  of  position  in  the  arm. 
But  this  is  illustrated  in  a  more  striking  man- 
ner by  reference  to  the  comparative  anatomy  of 
this  bone.  Those  animals  only  possess  a  well- 
developed  clavicle  whose  habits  of  life  require 
extensive  and  varied  movements  of  the  shoul- 
der. Where  the  anterior  extremity  is  employed 
merely  as  an  instrument  of  progressive  motion 
on  a  plane  surface,  we  have  no  clavicle ;  hence 
this  bone  is  absent  from  the  skeletons  of  Pa- 
chydermata,  Ruminantia,  Solipeda,  and  the  mo- 
tions of  the  shoulders  are  only  such  as  are 
required  for  the  flexion  and  extension  of  the 
limb.  In  the  Carnivora,  where  there  is  a  slight 
increase  in  the  range  of  motion  of  the  anterior 
extremities,  a  rudimentary  clavicle  exists,  and  in 
this  class  we  observe  that  the  size  of  the  bone  in 
the  different  orders  bears  a  direct  relation  to  the 
extent  of  motion  enjoyed  by  the  limb.  Thus 
it  is  smallest  in  the  Dogs  and  largest  in  the 
Cats;  in  these  animals  it  has  no  attachment  to 
either  the  sternum  or  the  scapula,  but  is  enclosed 
in  the  flesh,  and  does  not  occupy  much  more 
than  half  the  space  between  the  two  bones  last 
named.  "  But,  however  imperfect,"  says  Sir 
C.  Bell,  "  it  marks  a  correspondence  in  the  bones 
of  the  shoulder  to  those  of  the  arm  and  paw,  and 
the  extent  of  the  motion  enjoyed.  When  the 
bear  stands  up,  we  perceive,  by  his  ungainly 
attitude  and  the  motion  of  his  paws,  that  there 
must  be  a  wide  difference  in  the  bones  of  his 
upper  extremity  from  those  of  the  ruminant  or 
solipede.  He  can  take  the  keeper's  hat  from 
his  head  and  hold  it;  he  can  hug  an  animal  to 
death.  The  ant-bear  especially,  as  he  is  defi- 
cient in  teeth,  possesses  extraordinary  powers 
of  hugging  with  his  great  paws;  and,  although 
harmless  in  disposition,  he  can  squeeze  his 
enemy  the  jaguar  to  death.  These  actions  and 
the  power  of  climbing  result  from  the  structure 
of  the  shoulder,  or  from  possessing  a  collar-bone 
however  imperfect."* 

In  those  Mammalia  that  dig  and  burrow  in 
the  ground,  or  whose  anterior  extremities  are 
so  modified  as  to  aid  them  in  flight,  or  who 
are  skilful  in  seizing  upon  and  holding  objects 

*  Bridgcwatei  Treatise,  p.  48. 


156 


EXTREMITY. 


with  their  paws,  the  clavicle  is  fully  developed, 
and  extends  the  whole  way  from  the  scapula  to 
the  sternum.  Thus  in  the  Rodentia  this  bone 
is  very  perfect,  as,  for  example,  the  Squirrel, 
the  Beaver,  the  Rabbit,  the  Rat,  &c.  The  Bat 
affords  an  example  of  a  very  strong  and  long 
clavicle,  as  also  the  Mole  and  the  Hedgehog 
among  the  Insectivora. 

Among  the  Edentata  those  tribes  possess  a 
clavicle  whose  habits  are  fossorial,  as  the  Ant- 
eater,  the  Armadillos,  and  even  the  Gigantic 
Megatherium,  in  which  animal,  however,  the 
clavicle  presented  the  peculiarity  of  being  arti- 
culated with  the  first  rib  instead  of  with  the 
sternum.  In  the  Quadrumana  the  clavicles  are 
strong  and  curved  as  in  the  human  subject. 

In  Birds,  the  bone  which  is  analogous  to 
the  clavicle  presents  similar  variations  in  its 
developement,  according  to  the  range  of  motion 
required  in  the  anterior  extremity,  or  in  other 
words,  in  proportion  to  the  extent  to  which  the 
powers  of  flight  are  enjoyed.  Thus,  in  some 
these  bones  are  anchylosed  along  the  mesial 
line,  and  constitute  the  furculum  ;  in  others 
they  are  cartilaginous  internally;  and  in  others 
they  do  not  reach  the  sternum.* 

In  women  the  clavicle  is  in  general  less  curved 
than  in  men  ;  the  diminution  in  the  incurvation 
is  most  manifest  in  the  external  portion.  Accord- 
ing to  Cruveilhier,  the  clavicles  are  often  une- 
qually developed  in  the  same  individual  accord- 
ing as  one  limb  is  more  used  than  the  other,  and 
sometimes  the  difference  is  sufficiently  obvious 
to  enable  one  to  ascertain  from  the  relative  size 
of  the  clavicles,  whether  the  individual  is  right 
or  left-handed. 

Structure. — The  clavicle  contains  a  conside- 
rable proportion  of  compact  tissue  in  its  shaft, 
and  a  cylindrical  medullary  canal ;  at  the  ex- 
tremities the  compact  tissue  greatly  diminishes, 
and  is  replaced  by  the  reticular,  which  likewise 
fills  up  the  bone  and  obliterates  the  medullary 
cavity. 

Developement. — A  strong  argument  as  to  the 
great  importance  of  this  bone  to  the  motions  of 
the  shoulder,  is  derived  from  its  precocious  de- 
velopement ;  for  although  the  cartilaginous  nidus 
of  the  vertebrae  as  well  as  that  of  the  ribs  appear 
before  that  of  the  clavicle,  yet  the  latter  bone 
begins  to  ossify  sooner  and  is  completed  more 
rapidly  than  any  other  bone  in  the  body,  ex- 
cepting perhaps  the  lower  jaw,  which  some- 
times takes  the  precedence  in  the  process  of 
ossification.  It  is  remarkable  too  for  the  diver- 
sity in  its  proportional  size,  which  it  presents 
at  different  periods;  thus,  according  to  Meckel, 
about  the  middle  of  the  second  month  of 
pregnancy,  the  clavicle  is  four  times  longer 
than  the  humerus  or  femur,  and  it  is  not  until 
the  fourth  month  that  the  humerus  exceeds  it 
in  length.  The  clavicle  has  but  one  primitive 
point  of  ossification  :  a  supplementary  point  is 
developed  under  the  form  of  a  very  thin  lamella 
at  the  anterior  part  of  the  sternal  extremity  .f 

Scapula,  scapulum,  omoplata,  (wfto;,  hume- 
rus, wXaru;,  latus.)  Fr.  omoplate;  Germ,  das 
Schulterblatt. — This  bone  forms  the  posterior 

*  See  Avrs,  p.  285,  vol.  i. 

t  Cruveilhier,  Anat.  Desc.  t.  i.  p.  219. 


and  principal  portion  of  the  shoulder;  it  is 
placed  on  the  posterior  and  outer  part  of  the 
thorax,  and  occupies  a  space  which  extends  from 
the  second  to  the  seventh  rib. 

The  scapula  is  very  thin  in  the  greatest  part 
of  its  extent,  quite  papyraceous  in  some  places. 
It  is  triangular  in  form,  and  anatomists  com- 
monly describe  its  sides  or  borders,  its  angles, 
and  its  surfaces. 

The  borders,  or  costa,  of  the  scapula  are 
three  in  number,  and  are  named  according  to 
the  position  they  occupy  or  the  relation 
they  bear:  thus  there  are  the  superior  border 
or  cervical,  the  posterior  or  vertebral,  and  the 
anterior  or  axillary.  The  cervical  border  (also 
called  the  coracoid )  is  the  shortest,  being  some- 
what less  than  a  fourth  of  the  length  of  the 
vertebral  border;  it  is  connected  posteriorly 
with  the  vertebral  at  an  angle  the  apex  of  which 
is  rounded  off;  it  is  slightly  concave,and  the  bone 
for  some  way  below  it  is  very  thin,  and  the  bor- 
der itself  is  acute.  Anteriorly  it  terminates  in  a 
notch  which  is  bounded  in  front  by  one  root  of  the 
coracoid  process,  ( incisura  semilunaris,  lunula, 
coracoid  notch.)  This  notch  is  converted  into 
a  foramen  by  a  ligament  which  is  often  ossi- 
fied, and  thus  the  suprascapular  nerve,  which 
is  lodged  in  the  notch,  is  separated  from  the 
artery  of  the  same  name,  which  passes  over 
the  ligament.  The  extent,  therefore,  of  the 
cervical  border  is  from  the  posterior  superior 
angle  to  this  notch.  The  levator  anguli  sca- 
pulae and  the  omo-hyoid  muscles  are  attached 
to  this  border. 

The  vertebral  border,  also  called  the  base  of 
the  scapula,  is  the  longest,  being  in  an  ave- 
rage-sized bone  from  seven  to  eight  inches  in 
length ;  it  is  sharp  in  its  whole  extent,  which 
is  limited  above  by  the  posterior  superior  angle, 
and  below  by  the  inferior  angle.  At  the  junc- 
tion of  the  superior  fourth  with  the  remaining 
portion  there  is  an  inclined  surface,  triangular 
in  form,  the  base  confounded  with  the  margin 
of  the  bone,  the  apex  continued  to  the  spine. 
This  surface  is  smooth,  and  the  ascending 
fibres  of  the  trapezius  muscle  glide  over  it. 
To  that  part  of  this  edge,  which  is  above  the 
surface,  the  levator  anguli  scapulae  is  attached, 
and  below  it  the  rhomboidei. 

The  anterior  or  axillary  border  is  limited 
above  by  the  glenoid  cavity,  and  below  by  the 
inferior  angle  of  the  scapula.  It  is  much 
thicker  than  either  of  the  others,  and  its  thick- 
ness increases  towards  its  upper  extremity, 
where,  close  to  the  glenoid  cavity,  there  is  a 
rough  surface  which  gives  attachment  to  the  long 
head  of  the  triceps  muscle ;  inferior  to  this,  the 
edge  affords  insertion  to  the  teres  minor  muscle, 
and  still  lower  down  to  the  teres  major. 

The  superior  and  posterior  angle  is  formed 
by  the  junction  of  the  cervical  and  vertebral  bor- 
ders; it  is  a  little  less  than  a  right  angle,  and  is 
chiefly  remarkable  for  affording  insertion  to  the 
levator  anguli  scapula;  muscle.  The  inferior 
angle,  formed  by  the  union  of  the  axillary  and 
vertebral  borders,  is  very  acute;  the  bone  here  is 
very  thick  and  spongy ;  part  of  the  latissimus 
dorsi  glides  over  this  angle,  and  sometimes 
some  of  its  fibres  are  inserted  into  it.    It  is 


EXTREMITY. 


157 


only  this  portion  of  the  muscle  which  separates 
this  part  of  the  scapula  from  the  common  inte- 
guments, and  to  this  superficial  position  is  at- 
tributed the  more  frequent  occurrence  of  frac- 
tures from  direct  violence  in  this  than  in  any 
other  portion  of  the  bone. 

The  angle  between  the  cervical  and  axillary 
borders  is  truncated,  and  presents  many  points 
of  great  interest.    We  here  notice  an  articular 
concavity,  destined  to  contribute  to  the  for- 
mation of  the  shoulder-joint,  commonly  known 
under  the  name  of  the  glenoid  cavity,  (sinus 
articularis.J    This  cavity,  which   is  a  very 
superficial  one,  is  oval ;  the  long  axis  of  the 
oval  being  vertical  in  its  direction,  the  acute 
extremity  of  the  oval  is  situated  superiorly, 
and  here  the  edge  of  the  bone  is  cut  and 
rounded  off  towards  the  posterior  part,  where 
is  inserted  the  tendon  of  the  biceps.  The 
cavity  is  surrounded  by  a  thick  lip  of  bone, 
to  which  in  the  recent  state  the  fibre-cartilage, 
called  glenoid  ligament,  is  applied.    At  the 
internal  or  anterior  part  of  this  border,  is  a 
notch  for  the  passage  of  the  tendon  of  the  sub- 
scapularis  muscle.    The  aspect  of  the  glenoid 
cavity  when  the  scapula  is  quiescent  is  outwards 
and  slightly  upwards  and  forwards.  This  cavity 
is  connected  with  the  rest  of  the  bone  by  a  thick 
but  contracted  portion  denominated  the  neck 
of  the  scapula.    The  neck  of  the  scapula  is 
surmounted  by  a  remarkable  curved  process, 
called  the  coracoid  process,    (xopaf,  corvus.) 
This  process,  well  compared  to  a  semiflexed 
finger,  is  directed  forwards  and  outwards,  it  is 
connected  to  the  scapula  by  a  thick  portion, 
which  seems  to  arise  by  two  roots,  one  posterior, 
thick  and  rough,  lying  immediately  in  front 
of  the  notch  in  the  cervical  border,  the  other 
anterior  and  thin,  and  connected  with  the  apex 
of  the  glenoid  cavity.    The  concave  surface 
of  the  coracoid  process  is  directed  downwards 
and  outwards,  and  in  the  recent  state  projects 
over  the  upper  and  internal  part  of  the  shoul- 
der-joint: its  convex  surface  is  rough,  and  has 
inserted  into  it  the  ligaments  by  which  the 
clavicle  is  tied  to  it.     The  coracoid  process 
affords  attachment  by  its  internal  edge  to  the 
pectoralis  minor  muscle ;  to  its  outer  edge  is 
affixed  the  ligament  which,  with  the  acromion 
process,  completes  the  osseo-ligamentous  arch 
over  the  shoulder-joint,  and  by  its  summit  it 
gives  insertion  to  the  short  head  of  the  biceps 
and  to  the  coraco-brachialis. 

It  remains  only  to  examine  the  surfaces  of 
this  bone.  The  anterior  surface  forms  in  the 
greatest  part  of  its  extent  a  shallow  fossa,  fossa 
subscapularis,  which  is  limited  above  and  be- 
hind by  the  superior  and  posterior  margins  of 
the  bone,  and  in  front  by  a  smooth  and  rounded 
ridge,  which  extends  from  the  glenoid  cavity 
to  the  inferior  angle.  This  fossa  is  frequently 
intersected  in  various  directions  by  bony  ridges. 
Cruveilhier  remarks,  that  in  a  well-formed  per- 
son, this  surface  ought  to  be  exactly  adapted 
to  the  thorax;  but  when  the  chest  is  contracted, 
as  in  phthisical  patients,  the  scapula  not  par- 
ticipating to  a  proportionate  extent  in  the  con- 
traction, there  follows  such  a  change  of  re- 
lation that  the  scapula;  become  very  prominent 


behind,  and  are  in  some  degree  detached  from 
the  ribs  like  wings,  whence  the  expression 
scapula  alata,  applied  to  the  projection  of  the 
shoulders  in  phthisical  patients.  The  whole 
fossa  has  lodged  in  and  inserted  into  it  the 
subscapularis  muscle,  whence  its  name.  At 
the  superior  posterior  angle  and  the  inferior 
one,  are  rough  surfaces  into  which  are  inserted 
the  superior  and  inferior  fibres  of  the  serratus 
magnus  muscle. 

The  posterior  surface  is  remarkable  for  its- 
division  into  two  portions  by  a  large  process 
which  projects  from  it  nearly  horizontally  back- 
wards and  slightly  upwards.  This  process,  called 
the  spine  of  the  scapula,  is  fixed  to  the  bone 
at  the  line  of  union  of  its  superior  and  mid- 
dle thirds ;  it  commences  at  the  triangular 
surface  already  noticed  at  the  termination  of 
the  superior  fourth  of  the  vertebral  border  of 
the  scapula,  thence  it  proceeds  outwards,  in- 
clining a  little  upwards,  and  just  where  the 
neck  of  the  scapula  is  united  with  the  rest 
of  the  bone,  this  spine  ceases  to  be  connected 
with  the  scapula,  and  is  continued  outwards  in 
a  slightly  arched  form,  as  a  broad  and  flattened 
process,  denominated  the  acromion  process, 
(ax^o;,  summus,  w|ao{,  humerus.)  The  spine 
presents  posteriorly  a  thick  and  rough  edge, 
which  by  its  superior  border  gives  attachment 
to  the  trapezius  muscle,  and  by  its  inferior  to 
the  deltoid,  the  intervening  space  being  covered 
by  the  aponeurotic  expansion  which  connects 
the  muscles  last-named.  The  superior  surface 
of  the  spine  looks  nearly  directly  upwards;  it 
is  concave,  and  contributes  to  form  the  fossa 
supra-spinata.  The  inferior  surface,  on  the 
other  hand,  forming  part  of  the  fossa  supra- 
spinata,  is  convex  anteriorly  and  slightly  con- 
cave posteriorly,  and  looks  downwards  and 
backwards  ;  on  each  surface  we  observe  a  large 
nutritious  foramen.  The  posterior  edge  of  the 
spine  is  quite  subcutaneous,  and  the  physician 
often  finds  it  desirable  to  practise  percussion 
upon  it. 

Above  the  spine  of  the  scapula  is  the  fossa 
supra-spinata,  which  lodges  the  muscle  of  the 
same  name,  formed  in  front  by  the  scapula, 
behind  by  the  spine,  both  surfaces  being 
slightly  concave.  Below  the  spine  is  the  fossa 
supra-spinata  much  larger  than  the  preceding, 
slightly  convex,  except  towards  its  anterior 
part.  This  fossa  is  formed  by  the  scapula 
below  and  the  inferior  surface  of  the  spine 
above  ;  it  is  limited  in  front  by  a  ridge  which 
proceeds  downwards  and  backwards,  from  the 
glenoid  cavity  to  the  inferior  angle,  and  bounds 
behind  a  surface  which  gives  attachment  to 
the  teres  major  and  minor  muscles.  Into  this 
ridge  itself  is  inserted  a  fibrous  fascia,  which 
separates  the  attachment  of  the  last-named 
muscles  from  the  fossa  infra-spinata  and  the 
insertion  of  the  muscle  of  the  same  name.  The 
two  fossae,  thus  separated  by  the  spine,  com- 
municate through  a  channel  formed  on  the 
posterior  part  of  the  neck  of  the  scapula  and 
bounded  behind  by  the  spine ;  through  tin's 
channel  pass  the  arterial  and  nervous  ramifica- 
tions from  the  superior  to  the  inferior  fossa. 

The  acromion  process  is  evidently  continu- 


158 


EXTREMITY. 


ous  with  the  posterior  thick  edge  of  the  spine 
of  the  scapula,  and  viewed  from  above  ap- 
pears to  be  merely  an  expansion  of  it.  The 
narrowest  part  of  the  process  is  where  it  seems 
to  spring  from  the  spine,  forming  a  sort  of 
pedicle.  Its  posterior  surface  is  convex,  rough, 
covered  with  fibrous  tissue  in  the  recent  state ; 
its  aspect  is  upwards  and  backwards.  Here 
the  process  is  quite  subcutaneous  as  the  pos- 
terior part  of  the  spine  of  the  scapula.  The 
anterior  surface  is  concave,  smooth,  looks 
downwards  and  forwards  to  the  posterior  and 
superior  part  of  the  shoulder-joint.  The 
posterior  or  inferior  edge  of  the  process  con- 
tinuous with  the  corresponding  edge  of  the 
spine  of  the  scapula  forms  a  curve,  convex 
downwards  and  outwards,  and  terminates 
in  the  pointed  extremity  or  apex  of  the  pro- 
cess ;  all  this  edge  affords  attachment  to  the 
deltoid  muscle.  The  superior  edge  is  con- 
cave ;  near  the  apex  we  observe  upon  it  a 
plane  oval  articular  surface  to  which  the  acromial 
extremity  of  the  clavicle  is  articulated ;  into 
this  edge  the  trapezius  muscle  is  inserted. 
The  apex  of  the  acromion,  which  is  imme- 
diately in  front  of  the  articular  surface  for  the 
clavicle,  gives  insertion  to  the  apex  of  the  liga- 
ment, whose  base  is  attached  to  the  outer  edge 
of  the  coracoid  process. 

The  scapula  is  connected  to  the  trunk  through 
its  articulation  with  the  clavicle,  but  chiefly 
through  the  intervention  of  muscles,  so  that 
muscles  are  inserted  into  all  its  edges,  and  its 
surfaces  are  "  cushioned  with  muscles."  It  is, 
then,  as  might  be  anticipated,  a  very  moveable 
bone,  and  its  motions  consist  in  more  or  less 
extensive  revolutions  round  an  axis  through  its 
centre.  This  bone,  then,  being  the  medium 
of  connexion  between  the  pectoral  extremity 
and  the  trunk,  it  is  evident  that  the  great  move- 
ments of  the  former  must  depend  upon  the 
movements  produced  in  the  scapula  by  the 
muscles  which  pass  to  it  from  the  trunk ;  more- 
over, when  some  of  these  muscles  fix  the 
scapula,  it  becomes  the  point  whence  the  others 
act  in  producing  the  motions  of  the  ribs.  The 
scapula,  then,  is  an  essential  element  in  the 
upper  extremity,  and  it  exists  wherever  we 
find  that  limb  in  a  perfectly  developed  state, 
but  it  experiences  various  modifications  in 
position  and  shape  according  to  the  uses  to 
which  the  upper  extremity  is  applied.  In 
quadrupeds  the  position  of  the  scapula  is  more 
forwards  and  on  the  side  of  the  chest,  for  in 
them  the  anterior  extremity  is  employed  as  an 
instrument  of  support.  It  is  interesting  to 
observe  the  variation  in  the  aspect  of  the  glenoid 
cavity,  according  to  the  oblique  or  upright 
position  of  the  scapula,  indicating  whether 
the  pectoral  extremities  are  used  chiefly  as 
instruments  of  support  or  as  instruments  of 
prehension,  Stc.  When  freedom  and  rapidity 
of  motion  are  required  conjoined  with  strength, 
we  find  the  scapula  placed  obliquely  over  the 
ribs,  and  a  corresponding  obliquity  between 
the  humerus  and  scapula.  "  In  the  horse,  as 
in  most  quadrupeds,  the  speed  results  from 
the  strength  of  the  loins  and  hinder  extremities, 
for  it  is  the  muscles  there  which  propel  the 


animal.  But  were  the  anterior  extremities 
joined  to  the  trunk  firmly  and  by  bone,  they 
could  not  withstand  the  shock  from  the  descent 
of  the  whole  weight  thrown  forwards ;  even 
though  they  were  as  powerful  as  the  posterior 
extremities  they  would  suffer  fracture  or  dis- 
location. We  cannot  but  admire,  therefore,  the 
provision  in  all  quadrupeds  whose  speed  is 
great,  and  whose  spring  is  extensive,  that,  from 
the  structure  of  their  bones,  they  have  an 
elastic  resistance  by  which  the  shock  of  descend- 
ing is  diminished. 

"  If  we  observe  the  bones  of  the  anterior 
extremity  in  the  horse,  we  shall  see  that  the 
scapula  is  oblique  to  the  chest,  the  humerus 
oblique  to  the  scapula,  and  the  bones  of  the 
fore-arm  at  an  angle  with  the  humerus.  Were 
these  bones  connected  together  in  a  straight 
line,  end  to  end,  the  shock  of  alighting  would 
be  conveyed  through  a  solid  column,  and  the 
bones  of  the  foot  or  the  joints  would  suffer 
from  the  concussion.  When  the  rider  is  thrown 
forwards  on  his  hands,  and  more  certainly  when 
he  is  pitched  on  his  shoulder,  the  collar-bone 
is  broken,  because  in  man  this  bone  forms  a 
link  of  connexion  between  the  shoulder  and 
the  trunk,  so  as  to  receive  the  whole  shock; 
and  the  same  would  happen  in  the  horse,  the 
stag,  and  all  quadrupeds  of  great  strength  and 
swiftness,  were  not  the  scapula  sustained  by 
muscles  and  not  by  bone,  and  did  not  the 
bones  recoil  and  fold  up." 

"  The  horse-jockey  runs  his  hand  down  the 
horse's  neck  in  a  knowing  way  and  says,  '  this 
horse  has  got  a  heavy  shoulder,  he  is  a  slow 
horse.'  He  is  right,  but  he  does  not  under- 
stand the  matter;  it  is  not  possible  that  the 
shoulder  can  be  too  much  loaded  with  muscle, 
for  muscle  is  the  source  of  motion  and  bestows 
power.  What  the  jockey  feels  and  forms  his 
judgement  on  is  the  abrupt  transition  from  the 
neck  to  the  shoulder,  which,  in  a  horse  for  the 
turf,  ought  to  be  a  smooth  undulating  surface. 
This  abruptness  or  prominence  of  the  shoulder 
is  a  consequence  of  the  upright  position  of  the 
scapula;  the  sloping  and  light  shoulder  results 
from  its  obliquity.  An  upright  shoulder  is  the 
mark  of  a  stumbling  horse — it  does  not  revolve 
easily  to  throw  forward  the  foot."* 

A  comparison  between  the  skeleton  of  the 
anterior  extremity  in  the  elephant  and  in  one 
of  the  stag  kind  illustrates  how  the  oblique 
position  of  the  scapula  is  favourable  to  rapidity 
of  motion,  while  the  upright  position  is  that 
most  calculated  for  supporting  weight.  In  the 
elephant  the  glenoid  cavity  of  the  scapula  is 
placed  vertically  over  the  head  of  the  humerus, 
and  all  the  other  component  parts  of  the  limb 
are  similarly  disposed,  so  as  to  form  a  complete 
pillar  of  support  for  the  trunk.  Hence  the 
attitude  of  standing  in  the  elephant  requires 
but  slight  muscular  effort,  and  in  this  position 
he  is  in  such  complete  repose  as  often  to  obtain 
sleep.  In  this  animal,  then,  the  angle  between 
the  scapula  and  humerus  is  nearly  obliterated, 
but  in  the  stag  it  approaches  closely  to  a  right 
angle,  the  scapula  is  oblique  to  the  ribs,  and 

*  Sir  Charles  Bell,  Bridgewater  Treatise*' 


EXTREMITY. 


159 


the  humerus  to  the  scapula.  The  rule  seems 
to  be  that  where  the  pectoral  extremity  is  chiefly 
a  pillar  of  support,  the  aspect  of  the  glenoid 
cavity  is  nearly  vertically  downwards.  If  free- 
dom and  rapidity  of  motion  be  required  in 
addition  to  strength  as  a  member  of  support, 
the  trunk  being  lighter,  the  scapula  is  oblique, 
and  consequently  the  glenoid  cavity  looks 
downwards  and  forwards ;  or  if  the  limb  be 
not  used  to  support  the  trunk,  then  the  aspect 
of  the  glenoid  cavity  is  no  longer  downwards 
but  outwards,  as  in  man. 

Structure. — The  greatest  part  of  the  scapula 
is  composed  of  very  thin  almost  papyraceous 
compact  substance ;  but  its  processes,  and  the 
enlargements  at  its  edges  and  angles,  contain 
reticular  tissue. 

Developement. — This  bone  is  developed  by 
six  points  of  ossification ;  one  for  the  body, 
and  five  supplementary  ones,  viz.  one  for  the 
coracoid  process,  two  for  the  acromion,  one 
for  the  posterior  border  of  the  bone,  and  one 
for  its  inferior  angle.  The  ossification  of  the 
body  commences  about  the  second  month,  and 
the  spine  appears  in  the  third  month  as  a 
growth  from  the  posterior  surface  of  the  scapula. 

The  union  of  the  several  epiphyses  is  not 
completed  till  late,  and  it  is  not  until  after  the 
fifteenth  year  that  the  ossification  is  finished. 

The  bones  of  the  upper  extremity,  properly 
so  called,  are  the  humerus,  radius,  ulna,  and 
bones  of  the  hand. 

Humerus,  (os  brachii ;  Fr.  Vos  du  bras; 
Germ,  das  Oberarmbein ).  This  is  the  longest 
bone  of  the  upper  extremity;  it  is  situated 
between  the  scapula  and  forearm,  being,  as  it 
were,  suspended  by  muscle  and  ligament  from 
the  former. 

Like  all  long  bones,  the  humerus  consists 
of  a  shaft  and  two  extremities.  The  superior 
extremity  is  formed  by  a  smooth  and  rounded 
convexity,  rather  less  than  half  a  sphere ;  a 
slight  depression  in,  or  constriction  of,  the 
bone,  most  manifest  above,  marks  the  limit  of 
this  articular  eminence.  The  eminence  is 
called  the  head  of  the  humerus ;  the  constric- 
tion indicates  what  is  denominated  the  anato- 
mical neck  of  the  bone,  being  that  portion 
which  connects  the  head  to  the  shaft,  and 
analogous  to  the  more  developed  neck  of  the 
thigh-bone.  The  axis  of  the  neck  is  but  a 
continuation  of  that  of  the  head,  and  passes  in 
a  direction  from  within  outwards  and  down- 
wards, forming  an  obtuse  angle  with  the  axis 
of  the  shaft.  The  head  of  the  humerus  is 
entirely  covered  by  articular  cartilage,  and  arti- 
culates with  the  glenoid  cavity  of  the  scapula, 
to  which,  however,  it  obviously  does  not  at  all 
correspond  in  dimensions. 

The  inferior  part  of  the  anatomical  neck  of 
the  humerus  is  very  slightly  marked,  and  is 
continued  in  a  smooth  declivity  slightly  con- 
cave from  above  downwards,  into  the  shaft  of 
the  bone.  Its  superior  part  is  more  distinct, 
and  the  depth  of  the  groove  here  seems  in  a 
great  degree  owing  to  the  prominence  of  two 
bony  protuberances,  one  situated  anteriorly, 
called  the  lesser  tuberosity,  and  the  other  pos- 
teriorly, denominated  the  greater  tuberosity. 


The  lesser  tuberosity  of  the  humerus  ( tuber- 
culum  minus )  is  somewhat  conical  in  shape, 
and  inferiorly  it  ends  in  a  smooth,  rounded 
bony  ridge  (spina  tuberculi  minoris ),  which 
extends  downwards  and  inwards,  gradually 
diminishing  in  prominence  till  it  is  lost  in  the 
shaft  of  the  bone  at  the  inner  part  of  its  ante- 
rior surface.  The  lesser  tuberosity  gives  in- 
sertion to  the  tendon  of  the  subscapulars 
muscle,  and  the  ridge  or  spine  last  described 
forms  the  anterior  and  internal  boundary  of  the 
bicipital  groove. 

The  greater  tuberosity  (tuberculum  majus, 
externum  s.  posterius )  forms  a  considerable 
prominence  on  the  upper  and  outer  part  of 
the  humerus,  being  the  most  external  part  in 
that  situation  and  easily  to  be  felt  under  the 
integuments.  Superiorly  the  constriction  cor- 
responding to  the  anatomical  neck  separates  it 
from  the  head  of  the  humerus ;  inferiorly  it  is 
continued  into  and  gradually  lost  in  the  shaft 
of  the  bone  at  its  outer  part.  A  very  distinct 
and  prominent  ridge  ( spina  tuberculi  majoris) 
is  continued  from  its  anterior  extremity  down- 
wards and  inclining  very  slightly  inwards, 
which  terminates  about  the  middle  of  the  an- 
terior surface  of  the  bone,  just  internal  to  the 
deltoid  ridge.  This  ridge  is  most  prominent 
but  smooth  in  its  upper  third,  in  its  inferior 
two-thirds  it  is  less  prominent  but  rough ;  it 
forms  the  posterior  boundary  of  the  bicipital 
groove.  On  the  greater  tuberosity  three  dis- 
tinct surfaces  are  marked,  to  the  anterior  of 
which  the  supra-spinatus  muscle  is  attached, 
to  the  middle  the  infra-spinatus,  and  to  the 
posterior  the  teres  minor. 

The  bicipital  groove  commences  above  be- 
tween the  two  tuberosities,  and  passes  down- 
wards and  slightly  inwards,  bounded  before 
and  behind  by  the  spines  which  proceed  from 
those  tubercles.  This  groove,  very  distinct  at 
its  commencement,  ceases  to  be  so  a  little 
above  the  termination  of  the  superior  third  ; 
in  the  recent  state  it  is  lined  by  the  tendinous 
expansion  of  the  latissimus  dorsi  and  teres 
major  muscles,  and  lodges  the  tendon  of  the 
biceps  muscle,  whence  its  name. 

From  the  anatomical  neck  the  bone  gra- 
dually tapers  down  and  becomes  more  cylin- 
drical in  its  form ;  this  upper  portion  is,  for  the 
convenience  of  description,  distinguished  by 
the  name  of  surgical  neck  of  the  humerus. 
The  middle  third  of  the  shaft  of  the  bone 
is  prismatic  in  form  ;  the  external  spine 
whicli  commences  at  the  greater  tuberosity 
is  continued  down,  forming  a  prominent 
ridge  all  down  the  front  of  the  bone  to  the 
termination  of  its  flattened  inferior  third.  The 
outer  part  of  the  middle  third  of  the  humerus 
is  remarkable  for  the  rough  surface  into  which 
the  deltoid  muscle  is  inserted,  the  deltoid  ridge, 
situated  nearer  the  upper  than  the  lower  part 
of  this  portion,  and  directed  downwards  and 
very  slightly  forwards.  The  inner  part  of  the 
middle  third  presents  a  smooth,  flattened,  and 
inclined  surface,  which  is  continued  down  in 
this  form  to  within  a  very  short  distance  of  the 
inferior  extremity  of  the  bone.  The  posterior 
surface  is  rounded  and  very  smooth. 


160 


EXTREMITY. 


At  the  junction  of  the  middle  and  inferior 
thirds  we  notice  a  very  slight  and  superficial 
groove  passing  downwards  and  inwards,  and 
very  much  resembling  what  one  would  ima- 
gine might  be  produced  by  an  attempt  to  twist 
the  bone  while  yet  in  a  yielding  condition,  the 
inferior  third  having  been  twisted  inwards  and 
the  two  superior  thirds  outwards.  This  groove 
indicates  the  spiral  course  from  above  down- 
wards and  from  without  inwards  of  the  musculo- 
spiral  or  radial  nerve.  Below  this  groove  is  the 
inferior  third  of  the  humerus,  the  anatomical 
characters  of  which  are  very  distinct  from  those 
of  the  remaining  parts  of  the  bone.  A  pro- 
minent and  rounded  ridge,  continuous  with 
that  already  noticed  in  connexion  with  the 
greater  tuberosity,  passes  vertically  down  in 
front  of  it;  from  each  side  of  this  ridge  a 
smooth  surface  inclines  backwards,  forming 
an  inclined  plane  on  each  side  of  it,  the  ex- 
ternal being  larger  and  more  distinct  than  the 
internal. 

The  posterior  surface  of  the  upper  part  of 
this  portion  is  flat  and  very  smooth.  As  the 
bone  descends  it  expands  considerably  late- 
rally, so  as  to  present  in  front  a  broad  surface 
slightly  convex  from  side  to  side,  bounded  on 
either  side  by  prominent  edges,  continued  from 
the  edges  of  the  inclined  planes  above  de- 
scribed. Each  edge  terminates  in  a  pro- 
minence, the  inner  one  being  the  largest ;  the 
inner  edge  itself  being  thicker,  more  pro- 
minent, and  describing  a  slight  curve  as  it 
descends.  The  posterior  surface  is  limited 
below  by  a  deep  depression,  to  be  further  de- 
scribed hereafter.  Thus,  by  its  gradual  expan- 
sion laterally,  the  inferior  portion  of  the  hu- 
merus, being  about  one  fifth  of  the  entire 
length  of  the  bone,  has  a  triangular  figure,  the 
base  being  formed  by  the  inferior  articular  ex- 
tremity of  the  bone. 

The  whole  shaft  of  the  humerus  is  com- 
pletely clothed  with  muscle.  We  have  already 
indicated  the  place  of  insertion  of  the  deltoid 
muscle  on  the  outer  surface  of  the  bone ;  all 
that  portion  of  the  outer  and  anterior  surface 
below  the  deltoid  ridge,  and  for  a  little  way 
on  each  side  of  its  inferior  extremity,  is  co- 
vered by  the  brachiaeus  anticus  muscle.  In- 
ternal to  the  bicipital  groove,  on  the  inner 
surface  of  the  humerus,  about  its  middle,  the 
coraco-brachialis  muscle  is  inserted.  The  ex- 
ternal edge  below  the  spiral  groove  affords 
attachment  to  the  brachials  anticus,  supinator 
longus,  extensor  carpi  radialis  longior,  and  the 
triceps  muscles. 

The  internal  edge  below  the  insertion  of 
the  coraco-brachialis  has  the  brachiaus  anticus 
and  triceps  muscles  inserted  into  it,  and  both 
edges  afford  insertion  to  intermuscular  apo- 
neuroses, which  separate  the  muscles  con- 
nected with  the  anterior  from  those  on  the 
posterior  part  of  the  bone.  The  posterior  sur- 
face is  completely  covered  by  the  triceps  mus- 
cle, excepting  in  the  line  which  corresponds 
to  the  groove  already  referred  to,  in  which  the 
radial  nerve  and  musculo-spiral  artery  pass. 

The  foramen  for  the  nutritious  artery  is  found 
upon  the  internal  surface  at  the  inferior  ex- 


tremity of  its  middle  third ;  the  direction  of 
the  canal  is  downwards ;  sometimes  this  fora- 
men exists  upon'  the  external,  or  upon  the  in- 
ternal surface. 

The  inferior  extremity  of  the  humerus  is 
terminated  by  an  articular  cylinder,  which  pro- 
jects into  a  plane  anterior  to  that  of  the  shaft 
of  the  bone,  (processus  cubitalis ).  This  cy- 
linder is  placed  transversely,  but  in  transverse 
extent  it  falls  short  of  the  widest  part  of  the 
inferior  third  of  the  humerus.  Various  de- 
pressions and  elevations  are  marked  upon  the 
surface  of  this  cylinder.  Proceeding  from 
without  inwards,  we  notice  a  convexity  or 
rounded  head,  limited  externally  by  the  mar- 
gin of  the  cylinder  and  internally  by  a  groove, 
which  passes  in  a  curved  direction  from  before 
backwards,  the  concavity  of  the  curve  corres- 
ponding to  the  rounded  head.  This  head  is 
properly  denominated  the  external  condyle  of 
the  humerus ;  it  articulates  with  a  cavity  on 
the  head  of  the  radius  ;  the  anatomist  should 
notice  that  the  axis  of  this  head  passes  in  a 
direction  downwards  and  forwards.  On  the 
anterior  surface  of  the  humerus  immediately 
above  this  head,  we  observe  a  slight  and  very 
superficial  depression  which  receives  the  edge 
or  lip  of  the  cavity  of  the  radius,  when  the 
forearm  is  in  a  state  of  complete  flexion. 
Internal  to  the  groove  which  bounds  the  con- 
dyle on  the  inner  side,  we  have  a  pulley-like 
surface,  which  is  destined  for  articulation  with 
the  ulna.  The  concavity  which  forms  the  cen- 
tral part  of  this  pulley  is  deep,  but  deeper  and 
wider  behind  than  before;  its  anterior  ex- 
tremity terminates  in  communicating  with  an 
oval  depression  on  the  anterior  surface  of  the 
bone  (fovea  anterior  minor),  which  in  flexion 
of  the  forearm  receives  the  anterior  projecting 
angle  of  the  coronoid  process  of  the  ulna ; 
the  posterior  extremity  terminates  in  a  similar 
depression,  (fovea  posterior  v.  sinus  maximus,) 
but  a  much  deeper  one,  and  of  greater  dimen- 
sions generally,  occupying,  in  short,  nearly  the 
whole  posterior  surface  of  the  bone;  this  de- 
pression receives  the  olecranon  process  of  the 
ulna,  when  the  elbow-joint  is  in  extension. 
The  trochlear  concavity,  in  passing  from  before 
backwards,  takes  a  curved  direction,  so  that  its 
posterior  extremity  is  much  nearer  the  external 
part  of  the  articular  cylinder  than  the  anterior. 
This  has  an  important  influence  on  the  direc- 
tion of  the  motions  of  the  forearm.  These 
two  depressions  are  separated  from  each  other 
by  a  thin  osseous  lamina,  almost  transparent. 
We  sometimes  meet  with  instances  in  which 
this  lamina  is  perforated  in  consequence  of  a 
defect  of  ossification ;  and  Meckel  states  that 
he  has  found  this  perforation  more  frequently 
in  the  bones  of  Negroes  and  Papuas  than  in 
those  of  the  superior  races  of  mankind.  It  is 
the  permanent  condition  of  many  pachydermata, 
rodentia,  carnivora,  and  quadrumana.  On  the 
inside  the  trochlear  concavity  is  bounded 
by  a  thick  and  projecting  lip,  which,  when  the 
bone  is  placed  at  right  angles  with  a  horizontal 
plane  surface,  descends  lower  down  than  any 
other  part,  so  that  this  part  comes  in  contact 
with  the  plane  surface,  while  the  remaining 


EXTREMITY. 


portion  of  the  articular  cylinder  is  raised  con- 
siderably above  it.  This  arrangement  accounts 
for  the  hollow  angle  manifest  on  the  outer  side  of 
the  elbow-joint  when  the  forearm  is  extended. 

We  have  yet  to  describe  two  processes 
which  are  connected  in  great  measure  with  the 
outer  and  inner  extremities  of  the  articular  cy- 
linder, and  to  which  we  have  already  referred, 
as  being  the  points  in  which  the  margins  of 
the  bone  terminate.  The  external  one  is  trian- 
gular and  thick,  rough  upon  its  surface,  and 
projects  slightly.  It  is  improperly  called  the 
external  condyle — more  correctly  it  should  be 
designated  epicondi/le,  being  applied  to  the 
outer  surface  of  what  is  properly  the  external 
condyle.  This  process  affords  attachment  to 
the  external  lateral  ligament  of  the  elbow- 
joint  and  to  the  principal  supinator  and  ex- 
tensor muscles  on  the  forearm,  whence  it  has 
been  called  condylus  extensorius.  The  inter- 
nal process  is  very  prominent,  distinctly  trian- 
gular, terminating  the  inner  edge  of  the  hu- 
merus and  connected  with  the  trochlea;  it  is 
more  correctly  denominated  epitrochlea.  It 
affords  insertion  to  the  internal  lateral  ligament, 
and  to  the  pronator  and  flexor  muscles  of  the 
forearm.  Its  posterior  surface  is  slightly  hol- 
lowed at  the  line  of  its  junction  with  the  rest 
of  the  bone  ;  the  ulnar  nerve  passes  behind  it. 

The  humerus  is  the  principal  lever  of  the 
pectoral  extremity  ;  hence  in  all  animals  its 
strength  is  proportionate  to  the  force  and  power 
which  is  required  in  the  limb.  In  the  ele- 
phant it  is  a  massive  pillar  of  support;  and 
here  we  may  notice  a  variety  following  the 
same  law  which  influences  the  difference  in 
the  aspect  of  the  glenoid  cavity  of  the  scapula, 
already  noticed ;  namely,  that  the  angle  be- 
tween the  axes  of  the  head  and  shaft  of  the 
humerus,  is  at  its  maximum  when  the  arm- 
bone  is  mainly  an  instrument  of  support,  and 
diminishes  as  that  bone  is  more  used  for  pre- 
hension and  other  purposes ;  and  as  this  use  is 
found  for  this  bone  chiefly  in  the  human  sub- 
ject, we  may  presume  that  in  man  the  angle 
in  question  is  the  least  removed  from  a  right 
angle.  When  this  limb  is  used  mainly  for 
support  and  progression,  a  considerable  range 
of  motion  in  the  shoulder-joint  is  not  required, 
the  tuberosities  at  the  upper  extremity  of  the 
bone  project  and  limit  the  motions  of  the  joint. 
When,  however,  a  considerable  motion  is  ne- 
cessary,these  tubercles  are  depressed  as  in  man, 
so  as  not  to  interfere  with  these  motions.  The 
lower  extremity  of  the  humerus  likewise  affords 
marks  indicative  of  the  mobility  of  the  fore- 
arm and  hand ;  thus,  in  the  one  case  one  or 
both  of  the  edges  of  the  bone  which  terminate 
in  the  epitrochlea  and  epicondyle  are  promi- 
nent and  strong  in  proportion  as  the  muscles 
which  arise  from  it  are  frequently  called  into 
play,  as  when  the  pronating  and  supinating 
motions  of  the  forearm  are  extensive  :  in  the 
other  case  this  ridge  is  imperfectly  developed, 
and  the  principal  modification  of  the  lower  end 
of  the  bone  is  to  be  seen  in  the  articular  cy- 
linder, where  greater  depth  is  given  to  the 
trochlea,  in  order  to  afford  increased  strength 
and  security  to  the  elbow-joint. 

VOL.  II. 


One  of  the  most  singular  instances  of  the 
developement  of  bony  processes  in  accordance 
with  muscular  power  is  in  the  case  of  the  mole. 
In  this  little  animal  the  whole  anterior  ex- 
tremity is  constructed  entirely  with  reference 
to  its  burrowing  habits;  its  short,  thick,  and 
almost  square  clavicle  and  its  elongated  lever- 
like scapula  tend  to  the  same  end,  as  its  amaz- 
ingly strong  humerus.  The  upper  extremity 
of  this  latter  bone  is  extremely  broad ;  it  pre- 
sents two  articular  surfaces,  being  articulated 
with  the  clavicle  as  well  as  with  the  scapula, 
and  the  tuberosities  which  give  insertion  to 
the  muscles  of  rotation  are  enormously  de- 
veloped. The  body  of  the  bone  is  short,  thick, 
and  strong;  the  inferior  extremity  is  nearly  as 
large  as  the  superior ;  both  the  epicondyle  and 
epitrochlea  are  very  highly  developed,  especially 
the  latter,  which  is  accounted  for  by  the  fact  that 
the  muscles  of  pronation  are  those  most  called 
into  action,  in  order  to  enable  the  animal  to 
employ  the  accessory  bone  on  the  radial  side  of 
the  hand,  in  scraping  up  the  earth.  This 
large  size  of  the  humerus,  and  great  develope- 
ment of  its  muscular  eminences,  is  found  in  all 
fossorial  animals,  as  the  megatherium,  the  pan- 
golins, beavers,  ant-eaters,  moles,  and  mono- 
tremata.  In  the  two  last  the  developement  is 
the  most  remarkable. 

In  the  class  of  Birds,  the  humerus  is  de- 
veloped as  regards  the  prominence  of  its  mus- 
cular protuberances,  in  proportion  to  the 
powers  of  flight.  In  birds  which  fly,  those 
eminences  are  strong  and  prominent,  and  the 
bone  itself  is  proportionally  strong;  but  in  those 
which  do  not  fly,  the  bone  is  weak  and  gene- 
rally short.  In  the  common  pigeon,  for  ex- 
ample, the  enlargement  of  the  scapular  ex- 
tremity of  the  humerus,  and  the  developement 
of  the  tubercles  is  very  manifest,  as  well  as 
the  strength  and  thickness  of  the  shaft  of  the 
bone. 

Structure. — The  structure  of  the  humerus  is 
characteristic  of  that  of  long  bones  in  general. 
In  a  vertical  section  we  observe  that  the  re- 
ticular texture  is  chiefly  accumulated  towards 
the  extremities;  the  shaft  being  mainly  formed 
of  compact  tissue.  At  the  upper  extremity  we 
notice  the  mark  of  union  of  the  epiphysis  of 
the  head,  which  corresponds  to  the  line  of  the 
anatomical  neck  of  the  bone.  The  canal,  when 
a  transverse  section  of  it  is  viewed,  appears 
somewhat  quadrilateral  in  form.  Its  walls  are 
formed  of  very  dense  compact  tissue. 

Developement. — The  ossification  of  the  hu- 
merus begins  in  its  shaft,  and  that  very  early, 
according  to  Meckel  about  the  second  month  ; 
the  shaft  goes  on  enlarging,  but  the  extremities 
are  still  cartilaginous  during  the  whole  of  in- 
tra-uterine  life,  and  for  the  first  year  after  birth. 
The  superior  extremity  is  developed  by  two 
points  of  ossification,  one  for  the  head,  the 
other  for  the  great  tuberosity  ;  about  the  be- 
ginning of  the  second  year  the  ossification  of 
the  head  of  the  bone  commences,  and  from 
the  four-and-twentieth  to  the  thirtieth  month 
the  ossification  of  the  great  tuberosity  begins. 
According  to  Beclard,  a  small  ossific  point  for 
the  lesser  tuberosity  is  visible  in  the  fifth  or 

M 


162 


EXTREMITY. 


sixth  year ;  from  the  eighth  to  the  ninth  year 
the  ossifie  elements  of  the  head  of  the  hume- 
rus become  united  and  the  head  is  com- 
pleted. 

The  inferior  extremity  of  the  humerus,  accord- 
ing to  Cruveilhier,  begins  to  ossify  later  than  the 
superior.  The  first  point  of  ossification  noticed 
in  it  is  for  the  external  condyle:  this  appears  at 
the  age  of  two  years  and  a  half ;  at  seven  years 
a  second  point  of  ossification  commences  for  the 
epitrochlea;  at  twelve  a  third  point  appears  for 
the  internal  edge  of  the  trochlea;  and  at  sixteen 
years  a  fourth  point  for  the  epicondyle.  These 
four  points  of  ossification,  Cruveilhier  states,  are 
united  in  the  following  order:  first,  in  the 
second  year,  the  two  points  of  the  trochlea  are 
united ;  and,  secondly,  at  sixteen  years  the 
trochlea,  epicondyle,  and  the  condyle  form  a 
a  single  piece.*  The  union  of  the  extremities 
with  the  shaft  of  the  bone  takes  place  from  the 
eighteenth  to  the  twentieth  year;  and  all  ob- 
servers agree  in  stating  that  the  union  of  the 
inferior  extremity  with  the  shaft  always  pre- 
cedes that  of  the  superior  extremity,  although 
the  ossification  of  the  latter  is  prior. 

Forearm. —  The  bones  of  the  forearm  are 
the  ulna  and  radius,  of  which  the  former  con- 
stitutes the  second  essential  element  in  the 
elbow-joint,  the  radius  being  chiefly  an  acces- 
sory bone  to  provide  for  the  wider  range  of 
motion  of  the  hand.  The  ulna  therefore  is  the 
principal  lever  of  the  forearm,  and  the  motions 
of  flexion  and  extension  of  that  segment  of 
the  limb  upon  the  arm  depend  upon  it ;  at  its 
superior  extremity  it  forms  a  very  firm  hinge- 
jomt  with  the  trochlea  of  the  humerus,  but  in- 
feriorly  its  connexion  with  the  carpus  at  the 
wrist-joint  is  very  slight,  and  it  forms  by  no 
means  an  essential  element  of  that  joint.  On 
the  other  hand,  the  radius  at  its  inferior  ex- 
tremity forms  a  very  important  part  of  the 
wrist-joint,  but  at  its  superior  its  connection 
with  the  elbow-joint  is  due  to  its  necessary 
articulation  with  the  outer  side  of  the  ulna. 

Vina  (KV@nov,  cubitus;  Fr.  os  du  coitde ; 
Germ,  das  Elleribogenbein.f)  This  bone  is 
situated  on  the  inner  side  of  the  forearm.  It  is 
the  longest  and  the  largest  bone  of  that  region, 
and  in  the  vertical  position  of  the  limb  it  is 
directed  downwards  and  a  little  outwards,  the 
obliquity  being  occasioned  by  the  greater  pro- 
jection downwards  of  the  inner  lip  of  the 
trochlea  of  the  humerus,  as  already  alluded  to 
in  describing  that  bone. 

The  upper  or  humeral  extremity  of  the  ulna 
is  at  once  distinguished  by  its  great  size  from 
the  inferior  extremity.  It  consists  of  two  pro- 
cesses joined  to  each  other  at  a  right  angle,  and 
so  that  that  angle  opens  forwards.  One  of 
these  processes  is  vertical,  and  is  continued  in 

*  Cruveilhier,  Anat.  Descr.  torn.  i.  p.  231. 

t  The  term  focile  was  applied  to  this  bone  as  well 
as  to  the  radius  by  some  of  the  ancient  anatomists, 
in  imitation  of  the  Arabians,  who  used  the  word 
send,  sc.  an  instrument  analogous  to  our  tinder-box, 
which  consisted  of  two  sticks,  similar  in  appear- 
ance and  proportions  to  the  bones  of  the  forearm. 
Focile  majw  was  the  ulna,  focile  minus  the  radius. 
Blumenbach,  Beschreibung  der  Knochen,  p.  395. 


the  direction  of  the  long  axis  of  the  bone,  and 
is  little  else  than  a  continuation  of  the  shaft ; 
this  is  the  olecranon:  the  other  is  horizontal, 
anterior  to  the  olecranon,  as  it  were  placed 
upon  the  superior  extremity  of  the  bone,  so 
as  to  project  considerably  beyond  the  plane 
of  its  anterior  surface  :  this  is  the  coronoid 
process. 

The  olecranon,  (wXehi,  cubitus,  k^oivov,  caput,") 
also  called  processus  anconeus,  may  be  said  to 
begin  from  the  angle  of  junction  of  the  coro- 
noid process  with  it ;  there  the  bone  appears 
slightly  constricted,  for  above  that  point  it  ex- 
pands. We  notice  five  surfaces  upon  it.  The 
superior  surface  is  horizontal ;  it  presents  pos- 
teriorly a  muscular  impression  affording  inser- 
tion to  the  triceps  extensor,  and  anteriorly  it 
ends  in  a  remarkable  beak,  which,  in  the  state 
of  complete  extension,  is  received  into  the  ole- 
cranon cavity  of  the  humerus.  The  posterior 
surface  is  rough  with  a  very  obviously  trian- 
gular outline ;  this  surface  gives  insertion 
to  the  triceps  muscle.  The  internal  surface 
is  also  rough,  and  covered  by  the  fibrous  ex- 
pansion from  the  tendon  of  the  triceps,  and 
at  its  anterior  margin  affords  insertion  to  the 
superior  fibres  of  the  internal  lateral  ligament. 
The  external  surface  is  smooth,  and  also  is 
covered  by  the  fibrous  expansion  from  the  ten- 
don of  the  triceps.  The  anterior  surface  is 
articular ;  it  presents  the  appearance  of  having 
been  covered  by  articular  cartilage ;  it  is  divided 
by  a  rounded  vertical  ridge  into  two  unequal 
portions,  of  which  the  internal  is  larger  than 
the  external.  This  surface  is  limited  below  by 
a  transverse  depression,  non-articular,  in  which 
some  fatty  matter  is  deposited  in  the  recent 
state.  The  surface  is  convex  from  side  to  side 
in  the  centre,  and  each  of  its  lateral  portions  is 
concave ;  the  whole  surface  is  concave  from 
above  downwards.  In  the  extended  state  of 
the  forearm  this  articular  surface  of  the  olecra- 
non is  applied  to  the  posterior  part  of  the 
trochlea  of  the  humerus  ;  it  forms  the  posterior 
part  of  the  great  sigmoid  cavity  of  the  ulna. 

The  coronoid  process  is  wedge-shaped,  at- 
tached by  its  base  to  the  anterior  surface  of  the 
ulna,  the  sharper  edge  projecting  forwards  and 
free.  This  edge  is  convex,  and  sometimes 
forms  a  point ;  it  is  received  into  the  coronoid 
cavity  of  the  humerus.  On  the  external  sur- 
face of  the  coronoid  process  is  an  oval  articular 
facet,  concave  from  behind  forwards,  whose 
long  axis  is  horizontal ;  this  is  the  lesser  sigmoid 
cavity,  and  is  articulated  with  the  inner  side  of 
the  head  of  the  radius  ;  the  internal  surface  is 
rough,  and  has  a  projecting  lip,  which  affords 
attachment  to  the  anterior  fibres  of  the  internal 
lateral  ligament.  The  anterior  surface  is  in- 
clined from  above  downwards  and  from  before 
backwards,  so  that  its  aspect  is  downwards  and 
forwards ;  it  is  slightly  hollowed  transversely, 
and  is  rough,  the  roughness  being  continued 
down  for  a  little  way  in  front  of  the  bone,  thus 
forming  a  rough  surface  triangular  in  form,  the 
base  corresponding  to  the  anterior  edge  of  the 
coronoid  process ;  this  surface  affords  insertion 
to  the  brachiaeus  anticus  muscle.  The  superior 
surface  forms  the  anterior  portion  of  the  great 


EXTREMITY. 


163 


sigmoid  cavity;  like  the  similar  surface  on  the 
olecranon,  it  is  divided  by  an  obtuse  ridge 
directed  from  before  backwards,  into  two  une- 
qual portions ;  these  portions  correspond  in 
shape  and  size  with  those  already  noticed  on 
the  olecranon. 

The  shaft  of  the  ulna  gradually  tapers  from 
above  downwards ;  it  is  triangular  in  its  entire 
extent,  excepting  for  about  an  inch  above  the 
inferior  extremity,  where  the  bone  is  distinctly 
cylindrical.  On  the  shaft  anatomists  commonly 
describe  three  surfaces.  The  anterior  surface 
is  broader  in  the  middle  than  at  its  extremities; 
it  is  slightly  concave  in  the  transverse  direction 
in  its  middle  third  ;  on  this  surface,  at  its  upper 
part,  we  notice  the  orifice  of  the  nutritious  canal, 
which  is  directed  upwards  towards  the  coro- 
noid  and  olecranon.  By  its  three  superior 
fourths  this  surface  affords  attachments  to  the 
flexor  digitorum  profundus,  and  by  its  inferior 
fourth  to  the  pronator  quadratus;  the  place  of 
attachment  of  this  latter  muscle  is  limited  above 
by  an  oblique  line  which  passes  from  without 
inwards  and  from  above  downwards.  The  in- 
ternal surface  is  smooth,  and  convex  in  its  en- 
tire extent;  widest  above,  it  gradually  tapers  to 
the  inferior  extremity.  In  its  inferior  fourth  it 
is  subcutaneous,  and  to  its  three  superior 
fourths  is  attached  the  deep  flexor  muscle  of 
the  fingers  ;  the  aspect  of  this  surface  is  back- 
wards as  well  as  inwards. 

The  third  surface  is  posterior.  The  two  in- 
ferior thirds  of  this  surface  are  smooth,  the  mid- 
dle being  flat  and  the  lowest  rounded ;  here 
are  attached  the  extensor  muscles  of  the  thumb 
and  that  of  the  index  finger.  In  the  superior 
third  we  distinctly  notice  two  surfaces,  easily 
distinguishable  by  the  difference  of  aspect ;  the 
internal  one,  which  is  continued  up  on  the 
olecranon  process,  looks  backwards  and  slightly 
outwards;  to  it  the  anconaeus  muscle  is  attached 
superiorly,  and  inferiorly  the  extensor  carpi 
ulnaris.  The  external  of  these  two  surfaces 
looks  directly  outwards,  and  is  separated  from 
that  last  described  by  a  line  which  passes  ob- 
liquely downwards  and  inwards ;  to  this  sur- 
face, which  commences  just  below  the  lesser 
sigmoid  cavity,  the  supinator  brevis  is  attached, 
and  below  it,  commences  the  line  of  attachment 
of  the  extensor  muscles  already  alluded  to. 

Three  edges  separate  the  surfaces  above  de- 
scribed ;  of  these  the  external  is  at  once  distin- 
guished by  its  greater  prominence ;  it  is  sharp 
in  nearly  its  two  inferior  thirds,  and  superiorly 
is  lost  on  the  surface  to  which  the  supinator 
brevis  is  attached ;  all  that  part  of  this  edge 
which  is  prominent  and  sharp  gives  insertion 
to  the  interosseous  ligament.  The  anterior 
edge  commences  just  below  the  coronoid  pro- 
cess, and  terminates,  inclining  a  little  back- 
wards, in  front  of  the  styloid  process  of  the 
ulna :  it  is  rounded  and  smooth  in  its  entire 
extent,  and  has  the  deep  flexor  of  the  fingers 
and  the  pronator  quadratus  inserted  into  it. 
The  posterior  edge  commences  at  the  apex  of 
the  posterior  surface  of  the  olecranon,  and  ter- 
minates insensibly  towards  the  inferior  fourth 
of  the  bone. 

The  inferior  or  carpal  extremity  of  the  ulna 


is  very  small;  it  forms  a  slightly  rounded 
head ;  on  its  posterior  and  internal  part  is  a 
small  process,  projecting  vertically  downwards 
and  ending  in  a  point,  to  which  the  internal 
lateral  ligament  of'  the  wrist-joint  is  attached  : 
this  process  is  the  styloid  process ;  external  to  this 
is  a  depression  or  pit,  into  which  is  inserted 
the  triangular  cartilage  of  the  wrist-joint,  and 
external  to  this  depression  is  the  rounded  head, 
which  is  smooth  on  its  inferior  surface,  covered 
with  cartilage  in  the  recent  state  ;  the  triangular 
cartilage  glides  upon  this  surface.  On  the 
outer  side  of  the  head  is  an  articular  convexity 
which  articulates  with  a  concave  surface  on  the 
inner  side  of  the  carpal  extremity  of  the  radius. 
On  the  posterior  surface  of  the  head,  imme- 
diately external  to  the  styloid  process,  there  is 
a  slight  channel,  in  which  is  lodged  the  tendon 
of  the  extensor  carpi  ulnaris. 

Structure.  —  The  olecranon  and  coronoid 
processes  are  completely  cellular  in  structure, 
excepting  the  external  cortex  of  compact  tissue. 
The  inferior  extremity  of  the  ulna  is  likewise 
cellular,  but  the  shaft  is  mainly  composed  of 
compact  tissue,  hollowed  by  a  medullary  canal, 
which  commences  a  little  below  the  coronoid 
process,  and  terminates  just  above  the  inferior 
extremity. 

liadius,  (Germ,  die  Speiche,)  so  called  from 
its  being  compared  to  the  spoke  of  a  wheel ;  it 
is  the  shorter  of  the  two  bones  of  the  forearm  ; 
its  proportion  to  the  ulna  being  as  11  to  12. 

The  superior  extremity  or  head  of  the  radius 
is  a  cylindrical  head  excavated  on  its  superior 
surface  so  as  to  form  a  superficial  cavity,  cuvitas 
glenoidea,  which  is  articulated  with  the  external 
condyle  of  the  humerus.  The  circumference  of 
this  head  consists  of  a  deep  lip  of  bone  present- 
ing a  smooth  surface  covered  by  cartilage  in  the 
recent  state,  the  depth  of  which,  measured  verti- 
cally, is  greatest  on  the  inner  side,  so  as  there  to 
form  an  oval  convex  articular  facet  which  is 
adapted  to  the  lesser  sigmoid  cavity  of  the  ulna ; 
the  remainder  of  the  circumference  is  embraced 
by  the  annular  ligament  of  the  radius.  The  head 
of  the  radius  is  connected  to  the  shaft  by  a  short 
and  cylindrical  neck,  which  passes  obliquely 
downwards  and  inwards;  the  neck  of  the  radius 
is  limited  inferiorly  and  on  the  ulnar  side  by  a 
rounded  tubercular  process,  into  the  internal 
posterior  and  rough partof  which  the  biceps  mus- 
cle is  inserted,  the  bicipital  tuberosity  or  tubercle 
of  the  radius;  the  anterior  part  of  this  tubercle, 
over  which  the  tendon  of  the  biceps  glides,  is 
smooth.  For  about  an  inch  below  this  process 
the  bone  retains  the  cylindrical  form,  being 
here  embraced  by  the  inferior  fibres  of  the  su- 
pinator brevis  muscle;  but  below  this  the  bone 
becomes  distinctly  prismatic  in  its  form,  and 
begins  to  expand  to  its  inferior  or  carpal  extre- 
mity. We  here  describe  three  surfaces  as  in 
the  ulna :  the  anterior  is  inclined  inwards,  its 
aspect  is  forwards  and  inwards ;  about  its 
middle  this  surface  is  slightly  hollowed  from 
above  downwards;  at  the  junction  of  its  middle 
and  inferior  third  it  is  convex,  and  in  its  inferior 
third,  where  it  attains  its  greatest  lateral  expan- 
sion, it  is  concave  again.  At  the  superior  third 
of  the  bone  we  notice  on  this  surface  the  nutri- 


164 


EXTREMITY. 


tious  foramen,  the  canal  following  the  same 
direction  as  that  of  the  ulna,  namely  upwards. 
The  muscles  attached  to  the  anterior  surface  of 
the  radius  are  the  flexor  pollicis  proprius,  con- 
nected with  the  two  superior  thirds  of  the  bone, 
and  the  pronator  quadratus  occupying  the  in- 
ferior third.  The  posterior  surface  of  the  radius 
is  likewise  inclined,  and  looks  backwards  and 
inwards,  very  narrow  in  its  whole  extent,  but 
broadest  at  its  inferior  extremity,  convex  in  its 
superior  and  inferior  thirds,  and  slightly  con- 
cave from  above  downwards  in  its  middle  third. 
This  last  portion  of  the  bone  affords  attachment 
to  the  two  inferior  extensor  muscles  of  the 
thumb  ;  the  superior  third  is  embraced  by  the 
supinator  brevis,  and  the  inferior  third  has 
applied  to  it  the  tendon  of  the  common  extensor 
of  the  fingers,  the  indicator,  and  the  extensor 
tertii  internodii  pollicis.  The  external  surface 
is  convex  in  its  whole  extent,  and  like  the 
others  expands  inferiorly;  about  its  middle  we 
observe  a  rough  surface,  which  gives  insertion 
to  the  pronator  quadratus ;  in  its  upper  portion 
the  surface  is  embraced  by  the  supinator  brevis, 
and  inferiorly  the  radial  extensors  of  the  wrist 
are  applied  to  it. 

Of  the  three  edges  which  separate  these  sur- 
faces, the  internal  is  sharp,  and  extends  from 
about  an  inch  below  the  bicipital  tuberosity  to 
about  the  same  distance  above  the  carpal  extre- 
mity of  the  radius;  at  this  latter  point  the  edge 
seems  to  bifurcate  and  form  a  plane  triangular 
surface  above  the  inferior  extremity  of  the  ra- 
dius. This  edge  gives  attachment  in  its  entire 
extent  to  the  interosseous  ligament.  The  an- 
terior edge  is  rounded  ;  it  distinctly  originates 
from  the  bicipital  tuberosity,  and  terminates  at 
the  outer  side  of  the  carpal  extremity  of  the 
radius  in  front  of  the  styloid  process.  The  su- 
pinator brevis,  the  proper  flexor  of  the  thumb, 
and  the  flexor  sublimis  of  the  fingers,  have 
attachments  to  this  edge  above,  and  below 
the  pronator  quadratus  and  supinator  longus 
are  inserted  into  it.  The  posterior  edge  is  very 
imperfectly  defined,  being  distinct  only  in  its 
middle. 

The  inferior  or  carpal  extremity  of  the  radius 
is  the  largest  part  of  the  bone  ;  it  is  irregularly 
quadrilateral  in  form.  Its  inferior  surface 
forms  an  articular  excavation,  the  outline  of 
which  is  triangular,  the  apex  being  external 
and  the  base  internal ;  this  surface  is  divided 
into  two  by  a  slightly  prominent  line  which 
passes  from  before  backwards ;  the  outer  of 
these  two  portions  retains  the  triangular  form, 
and  is  articulated  with  the  scaphoid  bone  of 
the  carpus ;  the  internal  is  quadrilateral,  and 
articulated  with  the  lunar  bone.  At  its  inner 
margin,  this  surface  is  continuous  with  a  slightly 
excavated  articular  facet  on  the  ulnar  side  of 
the  inferior  extremity  of  the  bone,  which  is 
articulated  with  the  convex  surface  on  the  cor- 
responding part  of  the  ulna.  The  inferior  ex- 
tremity of  the  radius  presents,  at  its  outer  part, 
a  pyramidal  process  projecting  downwards  and 
slightly  outwards ;  this  is  the  styloid  process, 
which  by  its  apex  gives  attachment  to  the  ex- 
ternal lateral  ligament  of  the  wrist-joint.  The 
anterior  margin  of  the  inferior  extremity  is 


slightly  concave  from  side  to  side  ;  it  gives  at- 
tachment to  the  anterior  ligament  of  the  wrist- 
joint,  and  the  tendons  of  the  flexor  muscles  of 
the  fingers  pass  over  it  into  the  palm  of  the  hand. 
On  the  posterior  margin  of  this  extremity  we 
observe  two  grooves :  the  internal  one,  wide  and 
very  superficial,  lodges  the  tendons  of  the  com- 
mon extensor  of  the  fingers  and  the  indicator  ; 
the  external,  deeper  and  oblique,  lodges  the 
extensor  tertii  internodii  pollicis.  Externally 
we  notice  likewise  two  superficial  grooves,  of 
which  the  posterior  lodges  the  radial  extensors 
of  the  wrist,  and  the  anterior  is  traversed  by  the 
extensores  primi  et  secundi  internodii  pollicis. 

Structure — The  central  canal  extends  up- 
wards into  the  neck  of  the  bone;  it  is  cylin- 
drical at  the  extremities,  and  prismatic  in  the 
centre.  Both  extremities  are  composed  of  can- 
cellated structure. 

Developement  of  the  bones  of  the  fore-arm. — 
Both  bones  appear  about  the  same  time,  and  if 
not  synchronously  with  the  humerus,  at  least  a 
very  little  later.  With  both  bones  the  ossifi- 
cation begins  on  the  shafts,  which  are  very 
early  completed ;  the  ossific  point  of  the  shaft 
of  the  radius  is  said,  by  Beclard  and  Cruveil- 
hier,  to  begin  some  days  before  that  of  the 
ulna.  In  the  radius  the  inferior  extremity 
begins  to  ossify  before  the  superior,  about  the 
end  of  the  second  year.  The  ossification  of 
the  superior  extremity  begins  between  the 
seventh  and  ninth  year;  it  is  united  to  the 
shaft  about  the  twelfth  year,  whilst  the  inferior 
extremity,  whose  ossification  begins  earlier,  is 
not  united  till  the  eighteenth  or  twentieth  year. 
The  progress  of  the  ossification  of  the  ulna  is 
very  similar.  The  inferior  extremity  developed 
by  a  single  point  of  ossification  begins  first, 
about  the  sixth  year.  A  little  later  the  olecra- 
non begins  to  ossify;  the  coronoid  is  formed 
by  an  extension  of  ossification  from  the 
shaft.  The  union  of  the  superior  extremity  of 
the  ulna  with  the  shaft  takes  place  about  the 
fifteenth  or  sixteenth  year  ;  that  of  the  inferior 
about  the  eighteenth  or  twentieth. 

It  is  important  to  observe  that  the  articula- 
tion of  the  radius  with  the  ulna,  in  the  manner 
in  which  it  is  effected  in  man,  has  reference  to 
the  motions  of  the  hand.  Pronation  and  supi- 
nation of  the  hand  are  effected  by  the  rotation 
of  the  head  of  the  radius  within  the  coronary 
ligament  and  on  the  lesser  sigmoid  cavity  of 
the  ulna.  The  hand  is  so  connected  with  the 
radius  that  it  follows  the  motions  of  that  bone ; 
when,  therefore,  the  radius  rotates  in  such  a 
direction  that  its  inferior  part  crosses  the  ulna, 
the  posterior  edge  is  directed  outwards,  and  its 
anterior  surface  inwards  and  backwards;  the 
palm  of  the  hand  is  turned  backwards  and  the 
dorsum  forwards ;  the  forearm  and  hand  are 
then  said  to  be  in  pronation.  On  the  contrary, 
when  the  rotation  is  such  that  the  ulna  and  ra- 
dius are  placed  on  the  same  plane,  the  dorsum 
of  the  hand  is  directed  backwards  and  the  palm 
forwards  ;  this  is  supination. 

In  the  lower  animals  we  never  find  this  mode 
of  articulation  of  the  radius  with  the  ulna, 
unless  there  be  also  present  the  motions  of  su- 
pination and  pronation  of  the  hand.    In  such 


EXTREMITY. 


165 


animals,  evidence  of  the  existence  of  these 
motions  is  afforded  by  certain  points  in  the 
conformation  of  the  radius  and  ulna  them- 
selves, such  as  the  peculiar  form  of  the  head 
of  the  radius,  and  the  concave  articular  sur- 
face on  the  ulnar  side  of  its  lower  extremity, 
as  well  as  the  lesser  sigmoid  cavity  of  the 
ulna,  and  the  convexity  on  the  radial  side  of  the 
head  of  the  same  bone.  This  is  found  in  many 
of  the  Carnivora,  but  chiefly  in  the  Quadru- 
mana. 

In  the  Ruminants  and  Solipeds  the  radius 
and  ulna  are  consolidated  together  so  as  to 
form  one  bone;  they  can,  however,  be  distin- 
guished at  the  humeral  end,  where  the  latter 
bone  is  conspicuous  by  its  elongated  olecranon, 
which  not  only  affords  insertion  to  the  extensor 
muscles  of  the  arm,  but  also  increases  the  secu- 
rity of  the  elbow-joint.  The  radius,  which  is 
the  principal  bone  of  the  fore-arm,  is  so  arti- 
culated with  the  humerus  as  to  admit  of  free 
flexion  and  extension,  but  it  is  fixed  in  the 
state  of  pronation.  In  many  of  the  other  Mam- 
malia the  radius  and  ulna  are  distinct  through- 
out, but  do  not  admit  of  the  rotation  of  the 
one  on  the  other;  this  is  the  case  in  Rodentia, 
many  Carnivora,  Pachydermata,  Edentata,  In- 
sectivora,  and  Cetacea.  In  the  Sloth,  how- 
ever, among  the  Edentata,  the  motions  of  pro- 
nation and  supination  are  conspicuous,  and  the 
olecranon  is  imperfectly  developed ;  on  the 
contrary,  in  the  Edentata  proper,  as  the  Arma- 
dillo, Megatherium,  &c.  these  motions  do  not 
exist,  and  the  olecranon  is  very  much  deve- 
loped. In  the  Cheiroptera  the  radius  is  the 
principal  bone  of  the  fore-arm,  the  ulna  being 
developed  only  as  to  its  humeral  extremity 
consisting  sometimes  of  little  more  than  its 
olecranon  ;  and  in  some,  as  the  Vespertilio  vam- 
pyrus,  the  olecranon  exists  in  the  form  of  a  pa- 
tella, connected  with  the  upper  extremity  of 
the  ulna. 

In  Birds  the  radius  and  ulna  are  distinct 
throughout,  but  do  not  admit  of  motion  between 
them;  they  are  fixed  in  a  state  intermediate  be- 
tween pronation  and  supination. 

The  Hand.- — The  third  division  of  the  upper 
extremity  is  the  hand  :  for  the  description  of 
the  bones  which  compose  it,  we  refer  to  the 
article  Hand. 

Inferior  extremity. — The  bones  which  form 
the  skeleton  of  the  inferior  or  pelvic  extremity 
are  the  femur,  tibia,  fibula,  and  the  bones  of 
the  foot,  occupying  subdivisions  of  this  mem- 
ber, which  correspond  to  the  arm,  forearm,  and 
hand  in  the  pectoral  extremity. 

Femur  (thigh-bone,  os  Jemoris  v.  cruris,  os 
coxa.  Fr.  os  de  la  cuisse,  le  femur.  Germ,  das 
Schenkelbein.)  This  is  the  largest  and  longest 
bone  of  theskeleton;  it  constitutes  the  upper  part 
of  the  inferior  extremity,  and  is  articulated  with 
the  pelvis  above  and  the  tibia  inferiorly.  The 
femur  exhibits  very  obviously  the  characteristic 
marks  of  the  class  of  long  bones  in  its  elonga- 
ted and  cylindrical  shaft,  and  its  swollen  extre- 
mities. 

The  superior  extremity  of  the  femur  consists 
of  a  spherical  head,  connected  to  the  shaft  of 
the  bone  by  a  neck.    The  head  is  very  regu- 


larly spheroidal,  being  nearly  two-thirds  of  a 
sphere;  it  is  limited  towards  the  neck  by  a 
waving  line  which  passes  all  round,  and  corre- 
sponds to  the  margin  of  the  acetabulum.  The 
whole  head  of  the  femur  is  incrusted  in  the 
recent  state  with  articular  cartilage,  excepting 
at  one  point,  where  there  is  a  depression  or  pit, 
varying  in  depth  in  different  subjects.  The 
precise  situation  of  this  depression  is  just  infe- 
rior and  posterior  to  the  point  at  which  the  axis 
of  the  head  of  the  femur  would  pass  out :  into 
this  depression  the  ligamentum  teres  is  in- 
serted. 

From  the  head  of  the  femur  is  prolonged 
outwards  and  downwards  to  the  upper  end  of 
the  shaft  the  neck  (cervix  v.  colium  Jemoris ). 
This  portion  of  bone,  cylindrical  where  it  is 
connected  to  the  head,  gradually  expands  as  it 
proceeds  outwards,  and  is  flattened  in  front 
and  behind.  That  portion  of  the  neck  of 
the  femur  which  is  connected  with  the  shaft 
may  be  called  its  base;  here  we  observe  two 
lines,  by  which  the  demarcation  between  the 
neck  and  shaft  is  indicated  ;  one  of  these  lines 
is  anterior,  being  simply  a  rough  line  extending 
from  the  great  trochanter  obliquely  downwards, 
inwards,  and  slightly  backwards  to  the  lesser 
trochanter,  and  thence  called  the  anterior  inter- 
trochanteric line,  into  which  the  capsular  liga- 
ment of  the  hip-joint  is  inserted ;  the  other  line 
may  be  more  correctly  designated  a  prominent 
ridge  ;  it  is  situated  at  the  posterior  part  of  the 
base  of  the  neck,  and  extended  also  between  the 
trochanters,  the  posterior  intertrochanteric  line. 
The  anterior  surface  of  the  neck  of  the  femur  is 
for  the  most  part  plane,  but  slightly  concave 
just  external  to  the  line  of  junction  of  the  head. 
The  superior  surface  of  the  neck  is  concave, 
being  limited  on  the  outside  by  the  great  tro- 
chanter ;  the  posterior  surface  is  likewise  con- 
cave, being,  as  it  were,  hollowed  from  within 
outwards.  The  inferior  surface  is  slightly  con- 
cave from  above  downwards,  but  rounded  from 
before  backwards  :  this  surface  inclines  down- 
wards and  outwards,  and  at  its  termination  is 
connected  with  the  trochanter  minor  behind, 
and  the  inner  side  of  the  shaft  of  the  bone  in 
front ;  in  length  it  exceeds  all  the  rest ;  the  su- 
perior surface  is  the  shortest,  and  the  posterior 
is  longer  than  the  anterior.  On  all  the  surfaces 
of  the  neck  we  observe  numerous  foramina  for 
the  transmission  of  vessels  into  the  substance 
of  the  bone ;  these  foramina  are  largest  and 
most  numerous  on  the  superior  surface. 

At  the  superior  angle  of  the  base  of  the  neck 
of  the  femur,  and  at  the  upper  and  outer  part 
of  the  shaft  of  the  bone,  we  observe  a  large  and 
thick  process,  the  trochanter  major,  (from 
t^o^ocu,  roto,)  processus  exterior  Jemoris ;  it  is 
a  prolongation  upwards  of  the  shaft  of  the 
bone,  but  its  most  elevated  point  is  below  the 
level  of  the  head  of  the  bone,  corresponding  to 
the  upper  part  of  the  line  of  junction  of  the 
head  with  the  neck.  "  This  eminence,"  says 
Cruveilhier,  "  whose  size  is  considerable,  and 
which  makes  a  very  manifest  prominence  under 
the  skin,  ought  to  be  studied  with  care  in  its 
relations  as  to  its  relative  position  ;  first,  witli 
the  crista  ilii,  beyond  which  it  projects  exter- 


166 


EXTREMITY. 


nally ;  secondly,  with  the  external  condyle  of 
the  femur;  thirdly,  with  the  malleolus  exter- 
nus,  because  these  relations  are  constantly  va- 
luable guides,  as  well  in  the  diagnosis  as  in 
the  reduction,  of  the  luxations  of  the  femur  and 
of  the  fractures  of  the  neck  or  shaft  of  the 
bone." 

The  external  surface  of  the  great  trochanter 
is  convex  and  rough,  and  the  tendon  of  the 
gluteus  maximus  muscle  covers  it  in  the  recent 
condition  ;  this  surface  is  terminated  below  by 
a  projecting  line,  into  which  is  inserted  the 
upper  extremity  of  the  vastus  externus  muscle. 
The  internal  surface  is  of  much  less  extent :  it 
is  placed  at  right  angles  with  the  superior  sur- 
face of  the  neck  of  the  bone,  and  at  its  posterior 
part  it  is  excavated  so  as  to  form  a  deep  pit  or 
depression,  the  digital  cavity  or jfpssd  trochante- 
rica,  into  which  are  inserted  the  tendon  of  the 
pyriformis,  the  gemelli,  and  the  obturatores 
internus  and  externus.  The  anterior  edge  is 
thick  and  irregular ;  the  glutei  medius  and 
minimus  are  inserted  into  it,  the  former  into 
its  inferior,  the  latter  into  its  superior  part. 
Superiorly  the  trochanter  forms  a  thin  edge, 
more  or  less  pointed,  into  the  interior  half  of 
which  the  gluteus  minimus  is  inserted,  and 
into  its  posterior  or  pointed  portion  the  gluteus 
medius;  it  may  in  general  be  observed,  that 
the  size  of  this  pointed  part  of  the  superior 
edge  of  the  great  trochanter  is  proportionate  to 
the  developement  of  the  gluteus  medius  mus- 
cle. The  posterior  edge  is  convex  and  thick, 
and  gives  attachment  to  the  quadratus  femoris 
muscle. 

At  the  inferior  angle  of  the  base  of  the  cervix 
femoris,  and  on  the  internal  and  posterior  part, 
we  notice  a  short  conical  process,  trochanter 
minor,  ( processus  interior  femoris,)  attached 
to  the  bone  by  its  base, 1  its  apex  directed 
downwards,  inwards,  and  backwards,  smooth 
on  its  whole  surface.  This  process  affords 
insertion  to  the  tendon  of  the  psoas  and  iliacus 
muscles. 

In  the  maleadult,  theaxis  of  the  head  and  neck 
of  the  femur  passes  downwards,  outwards,  and 
slightly  backwards,  and  forms  an  obtuse  angle 
with  the  shaft,  an  angle  of  about  135  degrees. 
In  the  female  this  angle  is  somewhat  smaller,  and 
approaches  more  nearly  to  a  right  angle,  which 
contributes  with  the  greater  lateral  dimensions 
of  the  pelvis,  to  increase  the  distance  of  the 
trochanters  of  opposite  sides  from  each  other, 
and  to  cause  that  projection  of  these  processes 
which  forms  a  peculiarity  of  the  female  form. 
In  early  age,  when  the  neck  of  the  femur  is 
imperfectly  developed,  the  angle  between  the 
neck  and  shaft  is  not  defined  ;  in  the  earliest 
condition  the  connexion  of  the  head  and  shaft 
very  much  resembles  the  permanent  condition 
of  the  corresponding  parts  in  the  humerus ;  as 
the  neck  becomes  developed,  the  angle  is  ren- 
dered apparent,  at  first,  however,  little  removed 
from  a  right  angle,  but  subsequently  it  in- 
creases up  to  the  adult  period  ;  after  that  time 
we  often  find  that  the  neck  of  the  bone  dimi- 
nishes in  its  dimensions,  and  the  angle  is  con- 
sequently altered,  so  as  to  approximate  to  a 
right  angle. 


The  following  may  be  given  as  the  mean 
measurements  of  the  different  parts  of  the  neck 
of  the  femur.  In  the  centre  it  measures  about 
one  inch,  its  posterior  surface  about  fifteen 
lines,  its  inferior  edge  about  twenty  lines,  and 
its  superior  about  eleven  lines ;  its  vertical 
diameter,  in  its  most  contracted  part,  is  about 
seventeen  lines,  and  its  antero-posteiior  about 
ten. 

The  shaft  of  the  femur  forms  a  slight  curve 
from  above  downwards,  convex  anteriorly  and 
concave  posteriorly,  the  excavation  thus  formed 
behind  being  filled  up  by  the  powerful  muscles 
on  the  back  of  the  thigh.  It  likewise  presents 
the  appearance  as  if  it  had  been  twisted,  like 
that  which  we  have  noticed  in  the  humerus, 
the  inferior  extremity  being  twisted  inwards, 
the  superior  in  the  contrary  direction.  Cru- 
veilhier  remarks,  that  this  curvature  of  torsion 
is  in  relation  with  the  disposition  of  the  femoral 
artery,  which  in  its  spiral  course  passes  from 
the  anterior  to  the  posterior  surface  of  the  bone. 

In  the  greater  part  of  its  extent  the  shaft  of 
the  femur  is  prismatic ;  at  the  superior  extre- 
mity it  is  expanded  laterally  and  flattened  ;  at 
the  inferior  it  is  likewise  very  considerably  ex- 
panded. 

The  anterior  surface  of  the  shaft  is  smooth 
and  rounded ;  at  the  upper  part  it  is  a  little 
rough :  this  surface  is  covered  completely  by 
the  triceps  extensor  muscle.  The  posterior 
surface  is  divided  along  the  middle  into  two, 
which  are  inclined,  the  one  forwards  and  in- 
wards, the  other  forwards  and  outwards  ;  the 
external  surface  is  covered  by  the  vastus  exter- 
nus, the  internal  by  the  vastus  internus.  In 
the  middle,  separating  these  two  surfaces,  is  a 
rough  ridge,  tinea  aspera,  which  occupies  two- 
fifths  of  the  shaft  of  the  bone  about  its  middle, 
but  is  bifurcated  above  and  below.  Superiorly 
the  bifurcation  takes  place  about  the  termina- 
tion of  the  superior  fifth  ;  two  lines  proceed, 
the  external,  rough  and  prominent,  to  the  great 
trochanter ;  the  internal,  rather  indistinct,  to  the 
lesser  trochanter.  The  external  line  gives  in- 
sertion to  the  vastus  externus,  the  adductor 
magnus,  and  the  gluteus  maximus ;  the  pecti- 
nffius  and  the  vastus  internus  are  inserted  into 
the  internal  line.  Inferiorly,  the  bifurcation 
takes  place  at  a  point  corresponding  to  the 
commencement  of  the  two  inferior  fifths  ;  each 
line  proceeds  down  to  the  corresponding  con- 
dyle, and  a  triangular  space  is  thus  enclosed, 
the  base  of  which  is  formed  by  the  posterior 
extremities  of  the  condyles,  and  the  apex  is  at 
the  point  of  bifurcation  of  the  linea  aspera. 
This  space,  which  presents  a  smooth  surface, 
slightly  concave  in  both  the  vertical  and  trans- 
verse directions,  forms  the  floor  of  the  popliteal 
region.  The  external  line,  from  the  inferior 
bifurcation,  is  more  prominent  than  the  inter- 
nal, and  gives  insertion  to  the  vastus  externus 
and  to  the  short  head  of  the  biceps.  The  in- 
ternal is  very  faint  superiorly  where  the  femoral 
artery  passes  over  it,  and  inferiorly  the  vastus 
internus  and  the  adductor  magnus  are  inserted 
into  it. 

The  nutritious  foramen  of  the  femur  is  found 
either  upon,  or  on  one  side  of,  the  linea  aspera. 


EXTREMITY. 


167 


The  direction  of  the  canal  is  upwards  towards 
the  head  of  the  femur. 

The  inferior  extremity  of  the  femur  is  much 
more  considerable  than  the  superior.  We  no- 
tice upon  it  two  articular  processes  of  large 
size,  united  in  front,  but  separated  by  a  deep 
depression  posteriorly.  These  processes  are  the 
external  and  internal  condyles  ;  at  the  point  of 
union  of  these  two  condyles  in  front,  we  ob- 
serve a  transversely  concave  surface,  which  ex- 
tends for  a  little  distance  upwards  upon  the 
anterior  surface  of  the  bone ;  this  is  the  trochlea 
of  the  femur,  on  which  the  patella  moves.  The 
deep  notch  which  separates  the  condyles  poste- 
riorly is  denominated  the  intercondyloid  notch. 

Each  condyle  is  ovoidal  in  its  outline  and 
convex.  The  external  condyle  is  placed  di- 
rectly under  the  external  part  of  the  femur ;  it 
projects  more  forwards  than  the  internal  con- 
dyle ;  its  antero-posterior  diameter  is  less  than 
that  of  the  internal  condyle,  but  its  trans- 
verse is  greater.  On  the  other  hand,  the  in- 
ternal condyle  projects  inwards  out  of  the 
plane  of  the  internal  surface  of  the  bone; 
its  posterior  extremity  extends  much  further 
backwards  than  that  of  the  external,  and  if 
the  bone  be  placed  at  right  angles,  with  a 
plane  surface,  it  will  be  seen  that  this  condyle 
alone  touches  that  surface,  a  circumstance 
which  arises  from  the  internal  condyle  project- 
ing downwards  more  than  the  external.  It  is 
also  worthy  of  notice,  as  resulting  from  this 
conformation  of  the  internal  condyle,  that  in 
order  to  bring  both  condyles  in  contact  with  a 
plane  surface,  the  bone  must  be  made  to  in- 
cline with  the  inferior  extremity  inwards.  Above 
the  posterior  extremity  of  each  condyle  there  is 
a  depression  for  the  insertion  of  the  two  heads 
of  the  gastrocnemius  muscle. 

The  external  surface  of  the  external  condyle 
is  continuous  with  the  outer  surface  of  the 
shaft;  it  is  rough  and  convex,  and  is  called  by 
some  anatomists  the  external  tuberosity.  At  its" 
posterior  part  there  is  a  prominent  tubercle  to 
which  the  external  lateral  ligament  is  attached, 
and  below  and  a  little  posterior  to  this  is  a  de- 
pression into  which  the  tendon  of  the  popliteus 
is  inserted.  The  internal  surface  of  this  con- 
dyle forms  the  outer  wall  of  the  depression 
which  separates  the  condyles  behind ;  it  is 
concave,  and  has  the  anterior  crucial  ligament 
inserted  into  it.  The  inner  wall  of  this  notch 
is  formed  by  the  external  surface  of  the  in- 
ternal condyle,  which  is  likewise  concave,  and 
into  it  are  implanted  the  fibres  of  the  pos- 
terior crucial  ligament.  The  internal  surface 
of  this  condyle,  or  the  internal  tuberosity,  is 
rough,  much  more  convex  than  the  external 
tuberosity;  the  internal  lateral  ligament  and 
tendon  of  the  adductor  magnus  are  inserted 
into  it.  Both  the  tuberosities  are  perforated 
by  a  number  of  minute  foramina  for  the  trans- 
mission of  vessels  to  the  cancellated  texture. 

Structure. — A  vertical  section  of  the  femur 
demonstrates  its  structure  to  be  the  same  as 
that  of  all  the  long  bones,  composed  of  can- 
cellated texture  at  the  extremities  and  com- 
pact in  the  shaft,  which  is  bored  by  a  cylin- 
drical canal.    Posteriorly  the  compact  tissue  is 


of  great  density  and  hardness,  especially  where 
it  forms  the  linea  aspera  or  spine  of  the  bone. 
When  the  section  of  the  femur  is  made  so  as 
to  divide  the  neck  vertically  in  its  long  axis 
into  two  equal  portions,  we  observe  how  ad- 
mirably the  arrangement  of  the  osseous  texture 
in  this  part  is  adapted  to  the  function  which  it 
has  to  perform.  The  head  is  entirely  composed 
of  reticular  texture  surrounded  by  a  thin  cortex ; 
this  cortex  gradually  increases  in  thickness  on 
the  upper  surface  of  the  neck  till  it  reaches  the 
great  trochanter.  On  the  inferior  surface  of  the 
neck,  however,  the  compact  tissue,  although 
thin  near  the  head,  becomes  very  much  in- 
creased in  thickness  as  it  curves  downwards 
and  outwards  to  the  lesser  trochanter.  We 
observe,  moreover,  that  although  the  principal 
portion  of  the  head  and  neck  are  composed  of 
reticular  texture,  in  certain  parts  this  texture  is 
more  loose  than  in  others.  From  the  upper  part 
of  the  head  to  the  thick  part  of  the  compact  tissue 
on  the  inferior  surface  of  the  neck,  a  series  of 
parallel  fibres  proceed  in  an  oblique  course, 
and  closely  applied  to  one  another;  these  fibres 
receive  and  transmit  the  weight  to  the  arch  of 
the  neck.  Again,  the  reticular  texture  is  loose 
and  rare,  external  to  these  fibres  and  in  all  the 
inferior  part  of  the  head  of  the  bone  where  no 
stress  is  laid  upon  the  bone. 

Developemenl. —  According  to  Beclard,  the 
femur  begins  to  ossify  before  the  humerus;  its 
ossification  commences  about  the  thirtieth  day 
by  a  point  for  the  shaft.  A  second  point  of 
ossification  is  for  the  inferior  extremity,  and 
this  consists  in  a  single  osseous  nucleus  which 
is  formed  within  the  last  month  of  foetal  ex- 
istence, and  is  situated  between  the  two  con- 
dyles, occupying  the  centre  of  the  cartilage. 
According  to  Cruveilhier  this  osseous  nucleus 
appears  during  the  last  fifteen  days  of  intra- 
uterine life.  "  The  constant  presence,"  adds 
this  author, "  of  this  osseous  point  in  the  inferior 
extremity  of  the  femur  is  a  fact  of  great  im- 
portance in  legal  medicine  ;  because  from  the 
knowledge  of  this  circumstance  alone,  namely, 
that  this  nucleus  exists  in  the  epiphysis  of  the 
inferior  extremity  of  the  femur  of  a  fetus,  we 
can  pronounce  that  fetus  to  have  arrived  at  its 
full  period." 

The  neck  of  the  femur  is  formed  by  an  ex- 
tension from  the  body.  The  head  has  a  distinct 
point  of  ossification  which  begins  to  form  at 
the  end  of  the  first  year.  The  trochanters  have 
each  a  separate  point  of  ossification ;  that  of 
the  great  trochanter  is  formed  about  the  third 
or  fourth  year,  that  of  the  lesser  from  the  thir- 
teenth to  the  fourteenth  year.  These  several 
osseous  points  are  united  to  the  shaft  about  the 
period  of  puberty  in  the  following  order ;  first, 
the  trochanter  minor,  next  the  head  and  trochan- 
ter major,  and  lastly  the  inferior  extremity. 

In  the  skeleton  the  femur  is  articulated  so 
that  its  inferior  extremity  approximates  the 
corresponding  part  of  the  bone  of  the  op- 
posite side,  while  the  superior  extremities  are 
separated  from  each  other  to  a  considerable 
extent.  One  object  of  this  oblique  position  of 
the  femora  has  been  already  referred  to,  namely, 
to  bring  both  condyles  of  each  femur  in  con- 


168 


EXTREMITY. 


tact  with  the  articular  surfaces  of  the  vertical 
tibiae.  In  women,  in  consequence  of  the  more 
horizontal  position  of  the  neck  of  the  femur 
and  the  greater  width  of  the  pelvis,  the  ob- 
liquity is  more  manifest,  and  hence  they  are 
naturally  more  in-kneed  than  men,  as  from 
the  greater  projection  of  the  internal  condyle 
that  surface  alone  would  come  in  contact 
with  the  tibia  if  the  position  of  the  femur 
were  vertical.  The  separation  above  is  ef- 
fected by  the  neck  of  the  bone,  and  the  ad- 
vantage of  this  arrangement  is  to  give  a  more 
favourable  insertion  to  the  muscles  of  rotation  ; 
they  thus  acquire  a  lever  power  proportionate 
to  the  length  of  the  neck,  a  fact  which  is 
abundantly  manifest  by  comparing  the  relative 
powers  of  rotation  in  the  shoulder  and  hip 
joints;  in  the  former  these  motions  are  more 
extensive,  because,  from  the  peculiar  form  of 
the  joint,  the  obstacles  to  extent  of  motion  are 
fewer;  in  the  latter  they  are  effected  with  greater 
power  at  a  less  expense  of  muscular  force. 

In  comparing  the  femur  of  man  with  that  of 
the  lower  mammalia,  we  notice  the  imperfect 
developement  or  the  non-developement  of  the 
cervix  in  the  latter,  the  head  in  some  being 
placed  nearly  vertically  over  the  shaft  of  the  bone, 
and  also  the  small  size  of  the  trochanters,  and 
the  magnitude  of  the  trochanter  major  in  some 
classes.  The  curved  form  of  the  shaft  of  the 
femur  is  much  less  in  the  lower  mammalia 
than  in  man ;  in  some  the  femur  is  perfectly 
straight,  and  as  a  consequence  the  linea  aspera 
or  spine  is  indistinctly  marked.  The  propor- 
tionate length  of  the  femur  to  the  other  bones 
of  the  inferior  extremity  differs  also  :  in  man 
it  exceeds  that  of  the  tibia;  in  the  inferior 
mammalia,  although  in  most  cases  the  strongest 
bone,  the  femur  is  shorter  than  the  tibia,  and 
shorter  even  than  the  foot,  although  longer 
than  each  segment  of  this  portion  of  the  limb. 
The  trochlea  in  the  inferior  extremity  is  deeper, 
and  the  transverse  dimensions  of  the  condyles 
are  less  than  in  man. 

Patella,  (rotula,  knee-pan,  os  sesamoideum 
maximum,  Bertin  ;  Fr.  la  rotule ;  Germ,  die 
Kniesclieibe ).  This  bone,  although  belonging 
to  the  class  of  sesamoid  bones,  is  yet  so  fully 
developed  in  the  adult  human  subject,  and  is 
so  essential  to  the  integrity  of  the  knee-joint,  that 
it  is  usual  to  examine  its  anatomical  characters 
along  with  those  of  the  other  bones  of  the  in- 
ferior extremity.  Its  developement  in  the  tendon 
of  the  rectus  femoris  leads  to  its  being  classed 
among  the  sesamoid  bones. 

The  patella  is  of  a  triangular  form,  the  apex 
being  directed  downwards  and  the  base  up- 
wards ;  the  former  is  connected  with  the  tibia 
by  the  continued  tendon  of  the  rectus,  under 
the  name  of  ligamentum  patellae;  the  tendon 
of  the  rectus  and  the  tendinous  expansions  of 
the  triceps  extensor  are  inserted  into  the  base, 
which  expansions  are  likewise  implanted  into 
the  margins  of  the  bone,  so  that  the  whole 
circumference  and  anterior  surface  of  the  pa- 
tella are  invested  with  tendinous  fibres. 

The  anterior  surface  of  the  patella  is  very 
slightly  convex,  and  exhibits  a  fibrous  ap- 
pearance produced   by  vertical  and  parallel 


fibres,  with  narrow  fissures  between,  into 
which  the  fibrous  expansion  which  invests  this 
surface  is  implanted.  The  posterior  surface 
is  articular  and  adapted  to  the  trochlea  of 
the  femur.  A  vertical  ridge,  which  inclines  a 
little  outwards  in  its  descent,  divides  this  sur- 
face into  two  lateral  portions ;  each  of  these  por- 
tions is  a  concave  articular  facet  for  adaptation 
to  the  anterior  part  of  each  condyle  of  the 
femur,  and  consequently  there  is  between  these 
surfaces  the  same  inequality  which  exists  be- 
tween the  condyles.  In  the  recent  condition 
these  surfaces  are  covered  by  a  soft  and  very 
elastic  cartilage. 

Structure  and  developement. —  The  patella 
is  entirely  composed  of  cancellated  texture, 
the  anterior  surface  being  covered  by  a  thin 
lamella  of  very  fibrous  compact  tissue  already 
referred  to.  This  bone  is  developed  by  a  single 
point  of  ossification,  which  commences  about 
the  second  year. 

The  patella  exists  pretty  generally  among 
Mammalia,  also  among  Birds.  It  is  most  de- 
veloped in  the  Pachydermata  and  the  Solipeds, 
and  also  in  the  Monotremata ;  and  least  so  in 
the  Carnivora  and  Quadrumana.  It  is  absent  in 
Cheiroptera  and  Marsupiata.* 

Leg. — The  bones  that  form  the  second 
segment  of  the  inferior  extremity  are  the 
Tibia  and  Fibula. 

Tibia,  (shin-bone;  Germ,  das  Schienbein.) 
This  bone  is  situated  between  the  inferior  ex- 
tremity of  the  femur  and  the  astragalus.  Its 
length  is  to  that  of  the  femur  as  five  to  six. 
It  forms  the  principal  support  of  the  leg,  on 
the  inside  of  which  it  is  placed,  and  its  volume 
is  five  times  that  of  the  fibula.  After  the 
femur,  it  is  the  longest  bone  in  the  body,  being 
longer  than  the  humerus. 

The  upper  or  femoral  extremity  of  the  tibia 
is  thicker  and  broader  than  the  remaining  parts 
of  the  bone,  and  is  properly  the  head  of  the 
bone.  Its  transverse  extent  is  much  greater 
than  its  antero-posterior.  Its  superior  surface 
presents  two  bony  processes  lying  on  the  same 
plane,  denominated  condyles  of  the  tibia. 
Each  of  these  has  upon  its  superior  surface  a 
superficial  concave  articular  facet,  oval  with  long 
axis  from  before  backwards;  to  these  surfaces 
the  term  condyle  has  been  improperly  applied  ; 
but  they  are  more  correctly  called  the  glenoid 
cavities  of  the  tibia,  ( cavilates  glenoidea,  ex- 
terna et  interna).  These  cavities  correspond 
to  the  condyles  of  the  femur,  having  the  semi- 
lunar cartilages  interposed ;  the  outer  cavity 
approaches  more  to  the  circular  form  than  the 
internal  one ;  it  is  likewise  much  less  deep, 
and  at  its  posterior  part  it  is  even  convex. 
The  internal  one,  on  the  other  hand,  is 
uniformly  concave,  and  its  antero-posterior 
axis  greatly  exceeds  its  transverse.  These  sur- 
faces are  separated  in  the  centre  by  a  pyra- 
midal eminence  whose  apex  appears  bifurcated, 
the  subdivisions  of  which  are  separated  by  a 
narrow  rough  space.  This  is  the  spine  of  the 
tibia,  (acclivitas  intercondyloidea )  ;  it  corres 
ponds  to  the  intercondyloid'  fossa  of  the  femur 

*  Meckel,  Anat.  Compar. 


EXTREMITY. 


169 


where  the  crucial  ligaments  are  attached. 
Anterior  and  posterior  to  this  spine  are  two 
rough  depressions,  the  posterior  more  hollowed 
than  the  anterior :  into  the  former  the  posterior 
crucial  ligament  is  inserted,  and  the  latter  re- 
ceives the  anterior  crucial  ligament. 

The  circumference  of  the  head  is  rough  and 
perforated  by  a  vast  number  of  minute  vas- 
cular foramina.  Each  condyle  projects  late- 
rally beyond  the  plane  of  the  corresponding 
surface  of  the  shaft,  the  internal  to  a  greater 
extent  than  the  external.  These  lateral  pro- 
jections are  distinguished  by  the  name  of  Tu- 
berosities. The  internal  tuberosity  gives  in- 
sertion at  its  lower  part  to  the  internal  lateral 
ligament  of  the  knee-joint;  posteriorly  this 
tuberosity  is  grooved,  and  one  of  the  tendons 
of  the  semi-membranosus  is  inserted  into  the 
groove,  and  separates  the  internal  lateral  ligament 
from  the  bone  in  this  situation.  At  the  pos- 
terior part  of  the  external  tuberosity  there  is  a 
small  articular  facet,  nearly  circular  and  plane, 
with  which  the  fibula  is  articulated. 

In  front  of  the  head  of  the  tibia  there  is  a 
rough  triangular  surface,  the  apex  of  which 
is  directed  downwards  and  forms  a  promi- 
nence, which  is  smooth  at  its  superior  part,  but 
rough  inferiorly.  The  ligamentum  patellae  is 
inserted  in  the  latter  situation ;  the  smooth 
portion  indicates  the  position  of  a  bursa  which 
intervenes  between  the  ligament  and  the  bone. 
This  prominence  is  called  the  anterior  tube- 
rosity, and  by  some  anatomists  the  spine. 
From  the  inferior  rough  portion  of  this  tube- 
rosity there  passes  upwards  and  outwards  a 
prominent  line,  most  prominent  at  its  ter- 
mination, where  the  tibialis  anticus  muscle  has 
one  of  its  attachments. 

The  shaft  of  the  tibia  has  the  form  of  a 
triangular  prism  in  almost  its  whole  extent: 
at  its  inferior  third  this  form  is  less  distinct, 
in  consequence  of  the  angles  being  rounded  off. 
Of  the  three  surfaces  the  anterior  is  that  which 
presents  the  greatest  dimensions  :  it  is  smooth 
and  slightly  convex  in  its  entire  extent,  in- 
clined backwards  and  inwards,  subcutaneous, 
except  at  its  upper  part,  where  an  aponeurotic 
expansion  connected  with  the  tendons  of  the 
semi-tendinosus,  sartorius,  and  gracilis  muscles. 
The  inferior  fourth  of  this  surface  is  much 
more  convex  than  the  upper  portion,  and  looks 
directly  inwards.  The  external  surface  is  in- 
clined backwards  and  outwards,  and  is  con- 
cave in  its  three  superior  fifths,  convex  in  the 
rest  of  its  extent.  The  depth  of  the  superior 
concave  portion  is  proportionate  to  the  de- 
velopement  of  the  tibialis  anticus  muscle,  to 
which  it  gives  insertion.  The  inferior  con- 
vex portion  is  of  less  extent  than  the  superior, 
and  as  it  descends  it  experiences  a  change  of 
aspect,  so  as  to  look  directly  forwards.  This 
change  is  in  accordance  with  the  altered  di- 
rection of  the  tendons  of  the  tibialis  anticus 
and  extensor  muscles  of  the  toes,  which  lie  in 
contact  with  the  bone  in  this  situation.  The 
posterior  surface  is  expanded  at  its  extremities 
and  contracted  in  the  centre.  At  its  superior 
part  a  triangular  surface  is  marked  off  from 
the  rest,  towards  the  upper  extremity  by  an 


oblique  line,  which  proceeds  from  below  up- 
wards, and  from  within  outwards;  into  this 
line  are  inserted  the  poplitasus,  soloeus,  tibialis 
posticus,  and  the  long  flexor  muscle  of  the 
toes.  The  space  which  intervenes  between 
this  line  and  the  posterior  margin  of  the  head 
of  the  bone  is  covered  by  the  poplitaeus  muscle 
and  forms  part  of  the  floor  of  the  popliteal 
space.  Immediately  below  this  oblique  line, 
the  orifice  of  the  nutritious  canal  is  situated, 
penetrating  the  bone  obliquely  downwards ; 
this  canal  is  the  largest  of  the  medullary  canals 
of  the  long  bones  ;  and  Cruveilhier  states  that 
he  has  traced  a  nervous  filament  passing  into 
it  in  company  with  its  artery.  All  that  portion 
of  the  posterior  surface  which  is  below  the 
oblique  line  is  smooth  and  divided  by  a  ver- 
tical line,  which  is  variously  developed  in  dif- 
ferent subjects;  the  tibialis  posticus  muscle 
and  the  long  flexor  of  the  toes  are  attached  to 
this  surface. 

Three  distinct  edges  separate  these  surfaces. 
The  anterior  edge  ( crista  tibia )  is  very  promi- 
nent and  sharp  in  its  three  superior  fourths,  but 
rounded  off  below  :  in  its  upper  part  it  is  quite 
subcutaneous,  and  may  be  felt  under  the  skin. 
The  external  edge  forms  a  very  distinct  line  of 
demarcation  between  the  internal  and  posterior 
surfaces ;  it  gives  attachment  to  the  interosseous 
ligament,  and  at  its  inferior  extremity  it  bifur- 
cates and  encloses  a  concave  triangular  surface, 
in  which  the  fibula  rests.  The  internal  edge  is 
more  rounded  than  either  of  the  others ;  more 
distinct  inferiorly  than  superiorly.  At  its  up- 
per end  it  gives  insertion  to  the  internal  lateral 
ligament  of  the  knee-joint  and  the  popliteus 
muscle,  and  lower  down  to  the  solceus  and  the 
common  flexor  of  the  toes.  ^^.j..-—— 

The  inferior  or  tarsal  extneihity  of  the  tibia 
is  of  larger  dimensions  than  the  shaft,  although 
much  smaller  than  the  superior.  On  its  infe- 
rior surface  we  notice  a  quadrilateral  articular 
cavity,  of  greater  dimensions  transversely  than 
from  before  backwards,  concave  in  this  latter 
direction,  and  slightly  convex  transversely,  in 
consequence  of  the  existence  of  a  slight  ridge  in 
the  centre,  which  passes  from  before  backwards. 
This  surface  is  for  articulation  with  the  supe- 
rior part  of  the  body  of  the  astragalus  to  form 
the  ankle-joint. 

The  anterior  surface  of  the  inferior  extremity 
of  the  tibia  is  convex  and  rough  ;  it  gives  in- 
sertion to  the  anterior  ligamentous  fibres  of  the 
ankle-joint,  and  the  tendons  of  the  extensor 
muscles  pass  over  it.  The  posterior  surface  is 
very  slightly  convex ;  sometimes  a  very  super- 
ficial groove  exists  upon  it  for  lodging  the  ten- 
don of  the  flexor  pollicis  longus  ;  and  internal 
to  that,  and  lying  behind  the  internal  malleolus, 
a  more  distinct  and  constant  groove,  which 
passes  obliquely  downwards  and  inwards,  and 
lodges  the  tendons  of  the  tibialis  posticus  and 
flexor  communis. 

On  the  inside  of  the  inferior  extremity,  we 
observe  that  the  bone  is  prolonged  downwards 
and  slightly  inwards,  forming  a  thick  and  flat- 
tened process,  quadrilateral  in  form,  called 
malleolus  interims.  The  internal  surface  of 
this  process  is  rough  and  convex;  it  is  quite 


170 


EXTREMITY. 


subcutaneous;  its  external  surface  is  smooth, 
and  exhibits  a  triangular  articular  facet, 
which  is  united  at  a  little  more  than  a  right 
angle  with  the  articular  surface  on  the  inferior 
extremity  of  the  tibia;  by  this  facet  the  internal 
malleolus  moves  on  the  inner  surface  of  the 
body  of  the  astragalus.  The  apex  of  the  mal- 
leolus has  the  internal  lateral  ligament  of  the 
ankle-joint  inserted  into  it ;  the  anterior  edge 
gives  insertion  to  ligamentous  fibres,  and  the 
posterior  edge,  much  thicker  than  the  antgrior, 
is  closely  connected  with  the  posterior  surface 
of  the  inferior  extremity  of  the  tibia,  and  has 
upon  it  the  oblique  groove  already  referred  to. 
In  comparing  the  position  of  the  malleolus  in- 
ternus  with  that  of  the  internal  tuberosity  of 
the  tibia,  (which  may  best  be  done  by  laying 
the  bone  on  its  posterior  surface  on  a  horizontal 
plane,)  it  will  be  observed  that  the  malleolus  is 
considerably  anterior  to  the  tuberosity,  a  fact 
which  is  attributable  to  the  same  cause  which 
occasions  the  change  of  aspect  in  the  inferior 
part  of  each  of  the  three  surfaces  of  the  shaft, 
namely,  a  torsion  of  the  bone  similar  to  that 
already  noticed  in  the  other  long  bones  of  the 
extremities.  This  torsion  is  manifest  at  the 
junction  of  the  inferior  and  middle  thirds,  the 
lower  part  having  the  appearance  of  being 
twisted  inwards,  and  the  upper  part  outwards. 
The  outer  side  of  the  tarsal  extremity  of  the 
tibia  is  excavated  so  as  to  form  a  triangular 
surface,  rough  in  its  entire  extent,  to  which  the 
fibula  is  applied,  and  into  which  are  implanted 
the  strong  ligamentous  fibres  by  which  that 
bone  is  tied  to  the  tibia. 

Structure. — The  cancellated  texture  is  accu- 
mulate^ in  large  quantity  at  the  extremities, 
where,  especially  at  the  superior,  a  line  is  very 
frequently  apparent  on  the  whole  circumference, 
indicating  the  place  of  junction  of  the  epiphysis 
and  shaft.  The  medullary  canal  is  large,  ap- 
proaching the  cylindrical  form,  and  surrounded 
by  a  dense  compact  tissue. 

Fibula  (Fr.perone;  Germ.  Wadenbein). — 
This  bone  is  situated  on  the  outer  and  posterior 
part  of  the  tibia.  It  is  about  the  same  length 
as  that  bone,  but  as  its  upper  extremity  is  ap- 
plied to  the  under  surface  of  the  external  tube- 
rosity, its  inferior  extremity  projects  below  that 
of  the  tibia.  There  is  a  slight  obliquity  in  its 
direction,  and  in  consequence,  its  inferior  extre- 
mity advances  more  forwards  than  its  superior. 

The  fibula  is  a  very  slender  bone  in  its 
entire  extent,  however  its  extremities  are  a  little 
enlarged.  The  superior  extremity  or  head  of 
the  fibula  (capitulum)  is  somewhat  rounded  on 
its  inner  side,  flattened  on  its  external  surface, 
terminating  superiorly  in  a  point  into  which 
the  external  lateral  ligament  of  the  knee-joint 
is  inserted,  anterior  and  posterior  to  which  the 
edge  of  the  bone  receives  the  tendon  of  the 
biceps  muscle.  At  the  upper  and  anterior 
part  of  its  internal  surface  there  is  a  small  sur- 
face nearly  plane,  which  is  articulated  with  a 
similar  one  on  the  external  tuberosity  of  the 
tibia.  On  the  shaft  of  the  fibula  we  may  dis- 
tinguish three  surfaces,  but  in  consequence  of 
the  great  extent  to  which  the  fibula  appears  to 
have  undergone  torsion,  it  is  at  first  difficult  to 


detect  the  lines  of  demarcation  between  these 
surfaces.  The  ex  ternal  surface  is  very  narrow 
and  convex  in  its  upper  third,  gradually  ex- 
pands as  it  descends,  and  becomes  hollowed 
out  in  its  middle  third,  where  it  receives  the 
peroncei  muscles ;  in  both  these  portions  the 
aspect  of  this  surface  is  outwards  and  slightly 
forwards.  In  the  inferior  third  it  is  quite  flat, 
and  its  aspect  is  outwards  and  backwards.  The 
internal  surface  has  a  longitudinal  sharp  ridge 
upon  it,  which  gives  insertion  to  the  interosse- 
ous ligament.  This  crest  divides  the  internal 
surface  into  two  portions;  the  anterior,  very 
small,  in  some  cases  not  exceeding  two  or  three 
lines,  gives  attachment  to  the  extensor  muscles 
of  the  toes  and  the  peronaeus  tertius ;  the  pos- 
terior, much  more  considerable  and  slightly 
concave  longitudinally  for  about  its  two  supe- 
rior thirds,  has  the  tibialis  posticus  inserted 
into  it.  This  surface,  which  above  looks  nearly 
directly  inwards,  looks  forwards  in  its  inferior 
third.  The  posterior  surface  is  also  very  nar- 
row above,  and  expands  as  it  descends ;  upon 
it  the  twist  in  the  bone  is  very  obvious.  In 
its  superior  third  this  surface  looks  outwards 
and  backwards  ;  in  its  middle  third,  where  it  is 
much  more  expanded,  it  looks  directly  back- 
wards ;  and  in  its  inferior  third  its  aspect  is 
inwards,  and  here  it  terminates  in  forming  a 
rough  surface  which  is  adapted  to  the  similar  one 
on  the  fibular  side  of  the  inferior  extremity  of 
the  tibia.  Superiorly  the  posterior  surface  of  the 
tibia  gives  attachment  to  the  soloeus  muscle,  and 
lower  down  to  the  flexor  pollicis  proprius.  The 
orifice  of  the  nutritious  canal,  directed  down- 
wards and  forwards,  is  found  here. 

A  knowledge  of  the  edges  which  separate 
these  surfaces  will  assist  the  student  in 
understanding  the  position  of  the  surfaces 
themselves.  The  anterior  edge  begins  just 
below  the  head,  passes  down  in  front  of  the 
bone  as  far  as  the  middle,  then  becomes  exter- 
nal and  bifurcates,  enclosing  a  triangular  sur- 
face on  the  outside  of  the  inferior  extremity  of 
the  bone,  which  is  quite  subcutaneous.  The 
external  edge  is  at  first  external,  and  about  the 
commencement  of  the  inferior  third  it  begins 
to  wind  round  so  as  ultimately  to  become 
posterior.  The  internal  edge,  which  is  the 
most  acute,  and  is  more  prominent  in  the  centre 
than  at  its  extremities,  passes  forwards  inferiorly, 
and  terminates  in  front  of  the  inferior  extre- 
mity of  the  bone :  below  it  gives  attachment 
to  the  interosseous  ligament. 

The  inferior  extremity  is  long  and  flat,  and 
terminates  in  a  point;  it  extends  entirely  below 
the  inferior  articular  surface  on  the  tibia,  and, 
as  Cruveilhier  aptly  remarks,  it  forms  exter- 
nally the  pendant  to  the  malleolus  internus, 
which  it  exceeds  in  length  and  thickness ;  it  is 
consequently  called  the  malleolus  externus. 
The  internal  surface  of  the  external  malleolus 
presents  in  its  anterior  two-thirds  a  plane 
triangular  surface  for  articulation  with  the 
astragalus;  behind  this  surface  there  is  an 
excavation,  which  is  rough,  and  gives  insertion 
to  the  posterior  external  lateral  ligament.  The 
external  surface  is  convex  and  subcutaneous, 
and  the  posterior  surface  is  grooved  for  the 


EYE. 


171 


passage  of  the  tendons  of  the  peronan  muscles. 
The  apex  of  the  malleolus  is  directed  down- 
wards, and  is  the  point  of  attachment  of  the 
middle  external  lateral  ligament. 

Structure. — This  bone  is  very  light  and 
elastic,  a  property  rendered  necessary  by  the 
antagonist  muscles  which  are  inserted  into  its 
opposite  surfaces.  Its  extremities  are  composed 
of  cancellated  structure,  which  extends  some 
way  to  the  shaft  of  the  bone.  The  medullary 
canal,  very  narrow  and  irregular,  is  found  only 
in  its  middle  third. 

Developement  of  the  bones  of  the  leg. — The 
tibia  begins  to  ossify  somewhat  earlier  than  the 
fibula.  Both  bones  begin  to  ossify  in  their 
shafts  ;  the  ossific  point  of  the  shaft  of  the  tibia 
appears  about  the  middle  of  the  second  month. 
According  to  Meckel,  in  the  embryo  of  ten 
weeks,  the  fibula  is  not  above  half  the  length  of 
the  tibia;  after  the  third  month  the  two  bones  are 
nearly  equal.  Both  bones  have  an  ossific  point 
for  each  extremity.  The  superior  extremity  of 
the  tibia  begins  to  ossify  towards  the  termination 
of  the  first  year  after  birth.  The  inferior  extre- 
mity is  ossified  in  the  course  of  the  second 
year :  the  external  malleolus  is  a  prolongation 
of  the  inferior  extremity.  The  union  of  the 
extremities  with  the  shaft  commences  by  the 
inferior,  and  is  completed  from  the  eighteenth 
to  the  twenty-fifth  year.  The  ossification  of 
the  fibula  follows  nearly  the  same  course, 
excepting  that  the  superior  extremity  does  not 
begin  to  ossify  till  the  fifth  year. 

The  tibia  constitutes  the  principal  pillar  of 
support  to  the  leg.  It  is  placed  perpendicu- 
larly under  the  femur,  and  as  the  latter  bone 
is  inclined  inwards,  it  follows  that  there  must 
be  an  angle  formed  between  these  two  bones 
at  the  knee-joint,  a  very  obtuse  one,  with  its 
apex  inwards.'*  It  is  then  by  the  strength  and 
direction  of  the  tibia  that  the  leg  firmly  sup- 
ports the  body  in  the  erect  attitude;  the  fibula 
seems  not  to  contribute  at  all  to  the  solidity  of 
the  limb,  but  is  chiefly  employed  to  increase  the 
surface  of  attachment  for  the  muscles  of  the  leg. 

The  developement  of  the  tibia  and  fibula  in 
the  inferior  mammalia  is  pretty  similar  to  that 
of  the  radius  and  ulna.  The  tibia  is  always 
fully  developed,  and,  as  in  man,  is  the  prin- 
cipal bone  of  the  leg,  its  size  being  pro- 
portionate to  the  weight  and  strength  of  the 
animal.  Admitting  the  fibula  to  be  the  ana- 
logue of  the  latter  bone,  we  find  that,  as  it 
is  rudimentary  in  the  Solipeds  and  Ruminants, 
so  the  fibula  is  in  a  similar  condition  in  these 
animals.  In  the  former  animals  this  bone  is 
applied  to  the  external  side  of  the  head  of  the 
tibia  in  the  form  of  an  elongated  stilet,  termi- 
nating less  than  half  way  down  in  a  fine  point. 
On  the  other  hand,  in  Ruminants  it  is  only  the 
inferior  part  of  the  fibula  that  is  developed  ;  it 
appears  under  the  form  of  a  small  narrow  bone, 
extending  a  very  little  way  upwards,  and  form- 
ing the  external  malleolus. 

*  A  preternatural  obliquity  of  the  femur  causes 
a  corresponding  divergence  of  the  tibia  from  the 
perpendicular.  When  the  femur  is  directed  un- 
usually inwards,  the  tibia  is  directed  downwards 
and  outwards. 


In  Pachydermata  the  fibula  is  fully  deve- 
loped and  quite  distinct  from  the  tibia,  and 
very  small  in  proportion.  In  Edentata  the 
two  bones  are  fully  developed,  and  in  the 
Sloths  the  inferior  extremity  of  the  fibula  con- 
tributes to  form  the  articular  surface  for  the 
astragalus.  In  Rodentia  the  two  bones  are 
united  together  in  the  inferior  half,  as  also  with 
the  Insectivora,  particularly  in  the  Mole.  In 
many  Carnivora  these  bones  are  fully  developed 
and  detached :  this  is  particularly  manifest  in 
the  Pbocida;  and  the  Felidae.  In  the  Dogs, 
however,  the  fibula  is  attached  to  the  posterior 
part  of  the  tibia. 

For  the  description  of  the  bones  composing 
the  foot,  we  refer  to  the  article  under  that 
head ;  and  for  further  details  on  the  osseous 
system  of  the  extremities,  we  refer  to  the 
articles  Osseous  System  (Comp.  Anat.)  and 
Skeleton. 

Abnormal  condition  of  the  bones  of  the  extre- 
mities.— A  congenital  malformation  of  one  or 
more  of  the  extremities  is  classed  by  Isidore 
Geoffroy  St.  Hilaire  among  what  he  denomi- 
nates "  Monstres  Ectromeliens,"  of  which  he 
has  three  subdivisions :  1st,  where  the  hands 
or  feet  appear  to  exist  alone,  and  seem  to  be 
connected  with  the  trunk  without  the  inter- 
vention of  all  or  some  of  the  intermediate 
segments ;  these  he  denominates  Phocomeles, 
{(puxri,  Phoca,  and  p.EXo;,  membrum,)  from  their 
resemblance  to  the  permanent  condition  of  the 
aquatic  mammalia :  2d,  cases  in  which  there 
are  one  or  more  incomplete  limbs  terminating 
in  the  form  of  stumps :  to  these  he  gives 
the  name  Hemimeles:  and,  lastly,  where  the 
limb  or  limbs  are  wholly  absent  or  scarcely  at 
all  developed.  An  interesting  case  of  Phoco- 
melia  is  recorded  by  Dumeril ;  all  the  limbs 
were  in  this  condition,  owing  to  the  absence 
of  the  humerus,  and  forearm  bones  in  the  upper 
extremity,  and  the  presence  of  a  very  imperfect 
femur,  developed  only  as  to  the  head  and  tro- 
chanters, and  a  very  imperfect  tibia  in  the  lower 
extremity.  The  clavicle  and  scapula  were  pre- 
sent, but  presented  some  irregularities  of  form.* 
The  congenitaj  absence  of  these  last  bones  is 
rare  excepting  where  the  other  bones  of  the 
limb  are  also  absent. 

It  would  be  inconsistent  with  the  objects  of 
this  article  to  prosecute  this  subject  further;  we 
therefore  refer  for  further  details  to  the  article 
Monstrosity. 

For  Bibliography,  see  that  of  Anatomy 
(Introduction). 

(R.  B.  Todd.) 

EYE,  (in  human  anatomy),  ofpOafyto;,  orga- 
nonvisus;  oculus.  Yr.CEil;  Germ,  das  Auge  ; 
Ital.  Occ/ii'o. — The  human  eye  is  a  hollow  sphere, 
about  one  inch  in  diameter,  with  a  circular 
aperture  in  the  anterior  part  about  one-fifth  of 
this  sphere  in  breadth,  filled  by  a  transparent 
convex  portion  called  the  cornea,  through  which 
the  light  is  transmitted.    Within  this  hollow 

*  Hull,  de  la  Sor.  Philomath,  t.  iii.(  quoted  in 
Geoff.  St.  Hilaire 's  Anom.  de  1'OrganizaUon,  t.  ii. 
p.  211. 


172 


EYE. 


sphere,  and  at  a  short  distance  behind  the  trans- 
parent convex  portion  or  cornea,  is  fixed  a 
double  convex  lens,  called  the  crystalline  lens 
or  crystalline  humour;  and  between  this  cor- 
nea and  crystalline  lens  is  interposed  a  parti- 
tion or  screen  called  the  iris,  with  a  circular 
aperture  in  its  centre  called  the  pupil.  The 
inner  surface  of  this  hollow  sphere,  as  well  as 
the  back,  of  the  iris  or  screen,  are  covered  or 
stained  with  a  black  material.  The  space  be- 
tween the  cornea  and  crystalline  lens,  in  which 
the  iris  is  placed,  is  filled  with  a  transparent 
fluid,  called  the  aqueous  humour,  and  the 
space  between  the  crystalline  lens  and  the  bot- 
tom of  the  sphere  is  filled  with  a  similar  fluid, 
called  the  vitreous  humour.  The  annexed  figure 
represents  a  section  of  this  simple  piece  of  opti- 
cal mechanism,  much  larger  than  natural  to 
render  the  parts  more  distinct. 

Fig.  100. 


An  acquaintance  with  the  laws  which  regu- 
late the  transmission  of  the  rays  of  light  through 
transparent  bodies,  and  with  the  manner  in 
which  the  lenticular  form  changes  the  direction 
of  these  rays,:teaches ;"  ttyat  a  correct  image  of  ex- 
ternal objects  is  form^d-in -the  bottom  of  the  eye 
in  consequence  of  the^above  adjustment  of  its 
parts.  First,  the  rays  of  'light  acquire  a  con- 
vergence in  their  passage  through  the  cornea 
and  aqueous  humour,  then  the  central  portion 
of  the  pencil  of  rays  is  transmitted  through  the 
pupil,  and,  finally,  the  rays  in  their  passage 
through  the  crystalline  lens  acquire  such  addi- 
tional convergence,  that  they  are  brought  to  a 
focus  on  the  bottom  as  represented  in  the  an- 
nexed diagram. 


Such  are  the  essential  component  parts  of 
the  eye,  considered  as  a  piece  of  optical  me- 
chanism, but  viewed  as  a  piece  of  anatomical 
mechanism,  its  construction  is  much  more  com- 
plicated, and  the  materials  of  which  it  is  com- 
posed are  necessarily  totally  different  from  those 
of  any  human  contrivance  of  a  similar  nature. 
It  lives  in  common  with  the  body  of  which  it 
forms  a  part,  it  grows  and  is  repaired ;  conse- 
quently, the  animal  organisation  destined  for 
such  functions  must  constitute  an  essential 
part  of  its  construction. 

The  organ  derives  its  permanent  spherical 
form,  its  external  strength,  and  the  support  of 
the  delicate  parts  within  it,  from  a  strong  opaque 
membrane  called  the  sclerotic  coat;  while 
the  convex  portion,  called  cornea,  in  front, 
equally  strong,  being  transparent,  allows  the 
rays  of  light  to  pass  without  interruption.  The 
interior  of  the  portion  of  the  sphere  formed  by 
the  sclerotic  coat  is  lined  throughout  by  a  soft 
membrane  called  the  choroid,  necessarily  con- 
stituting another  hollow  sphere,  accurately 
adapted  and  adhering  to  the  inside  of  the  for- 
mer. This  also  has  its  circular  aperture  ante- 
riorly, into  which  is  fitted  the  screen  called  iris, 
as  the  cornea  is  fitted  into  the  aperture  in  the 
sclerotic.  While  the  external  surface  of  this 
choroid  coat  is  comparatively  rough  and  coarse 
in  its  organization,  as  it  adheres  to  the  equally 
coarse  surface  of  the  sclerotic,  the  interior  is 
exquisitely  smooth  and  soft,  being  destined  to 
embrace  the  retina,  another  spherically  dis- 
posed membrane  of  extreme  delicacy.  The 
screen  called  iris,  which  is  fitted  into  the  cir- 
cular aperture  anteriorly,  is  as  different  from 
the  choroid  coat  in  its  organization  as  the  cor- 
nea is  from  the  sclerotic:  it  is  perfectly  plane, 
and  therefore  forms  with  the  concave  surface 
of  the  cornea  a  cavity  of  the  shape  of  a  plano- 
convex lens,  called  the  anterior  chamber.  In 
or  on  the  choroid  coat  the  principal  vessels  and 
nerves,  destined  to  supply  the  interior  of  the 
organ,  are  distributed,  and  in  its  texture  and 
upon  its  inner  surface  is  deposited  the  black 
material,  which  in  this  part  of  the  chamber,  as 
well  as  on  the  back  of  the  iris,  is  so  essential  a 
provision.  At  the  anterior  margin  the  choroid 
is  more  firmly  united  to  the  corresponding  mar- 
gin of  the  sclerotic  by  a  circular  band  of  pecu- 
liar structure  called  the  ciliary  ligament,  and  on 
its  inner  surface,  in  the  same  place,  it  is  fur- 


Fig.  101. 


EYE. 


173 


nished  with  a  circle  of  prominent  folds  called 
ciliary  processes,  by  means  of  which  it  is  united 
to  the  corresponding  surface  of  the  hyaloid 
membrane  of  the  vitreous  humour.  The  an- 
nexed figure  represents  a  section  of  this  hollow 
sphere  lodged  within  the  sclerotic  sphere.  The 
external  circle,  a  a,  between  the  two  black 
lines  represents  a  section  of  the  strong  opaque 
membrane  called  the  sclerotic,  which  consti- 
tutes the  case  or  resisting  sides  of  the  organ  ; 
b  is  the  transparent  lenticular  window  called 
cornea,  which  fills  the  aperture  left  in  the  ante- 
rior part  of  the  sclerotic  for  its  reception  ;  d  d  is 
the  place  of  union  between  the  sclerotic  and 
cornea,  to  which  the  ciliary  ligament  on  the 
outside  of  the  anterior  margin  of  the  choroid 
sphere  corresponds ;  e  e  the  circle  bounded 
by  the  line  marking  the  inner  surface  of  the 
sclerotic  externally,  and  by  the  shaded  part  in- 
ternally, represents  a  section  of  the  hollow 
sphere  called  choroid.  At  the  point  d  d,  cor- 
responding to  the  place  of  union  between  the 
sclerotic  and  cornea,  this  choroid  projects  exter- 
nally, encroaching  upon  the  sclerotic  in  a  pecu- 
liar manner,  to  be  presently  described  as  the 
ciliary  ligament;  while  at  the  ■same'1  point  it 
projects  internally  in  the  shape  of- -a"  series  of 
folds,  to  be  described  as  the  ciliary  processes. 
The  white  productions  extending  from  the  same 
points  in  a  vertical  direction  into  the  chamber 
of  the  aqueous  humour,  between  the  eorhe'a  ahd 
crystalline  lens,  represent  a  section  of  - the 
screen  called  the  iris,  f  is  a  section  of  the 
crystalline  lens.  "  ?! 

Fig.  102. 


a 


Through  a  small  aperture  in  the  sclerotic 
apd  choroid  membranes  in  the  bottom  of  the 
eye,  the  optic  nerve  is  transmitted,  and  imme- 
diately expands  into  a  texture  of  the  most  ex- 
quisite delicacy,  called  the  retina.  This  con- 
stitutes a  third  spherically  disposed  membrane, 
not  however  of  the  same  extent  as  the  sclerotic 
or  choroid,  being  discontinued  at  a  distance  of 
about  an  eighth  of  an  inch  from  the  anterior 
margins  of  these  membranes.  This  is  the  ner- 
vous expansion  endowed  with  the  peculiar 
description  of  sensibility  which  renders  the  ani- 
mal conscious  of  the  presence  of  light.  The 
globe  of  the  eye,  as  above  described,  is  ob- 
viously divided  by  the  iris  into  two  chambers  of 
very  unequal  dimensions;  that  in  front  bound- 


ed by  the  cornea  being  very  small,  and  that 
behind  bounded  by  the  retina  being  very  large. 
This  large  posterior  chamber  is  distended  by  a 
spherical  transparent  mass,  called  the  vitreous 
humour,  which  does  not,  however,  fill  this  pos- 
terior chamber  completely,  but  is  discontinued 
or  compressed  at  a  short  distance  behind  the 
iris,  leaving  a  narrow  space  between  it  and  that 
membrane,  called  the  posterior  chamber  of  the 
aqueous  humour.  This  spherical  mass  is  of  ex- 
tremely soft  consistence,  and  is  composed  of  a 
delicate  transparent  cellular  membrane  called 
the  hyaloid  membrane,  the  cells  of  which  are 
distended  with  a  transparent  fluid.  In  the 
small  space  between  the  anterior  part  of  the 
vitreous  humour  and  the  back  of  the  iris,  called 
the  posterior  chamber  of  the  aqueous  humour, 
and  lodged  in  a  depression  formed  for  its  re- 
ception in  the  vitreous  humour,  is  placed  the 
double  convex  lens  called  the  crystalline  lens. 
The  relation  of  these  parts  to  each  other  may 
be  seen  in  the  last  figure,  and  the  one  below 
represents  the  optic  nerve  expanded  in  the 
form  of  a  spherical  membrane  over  the  sphere 
of  vitreous  humour,  with  the  crystalline  lens 
lodged  Sn  a  depression  on  the  anterior  part  of 
that  sphere,  and  surrounded  by  a  circle  of 
radiating  lines,  which  are  delicate  folds  corres- 
ponding to  the  folds  of  the  choroid,  called  the 
ciliary  processes. 

Fig.  103. 


The  piece  of  animal  optical  mechanism  thus 
constructed  is  lodged  in  an  open  cavity  of  the 
skull  called  the  orbit,  and  js  furnished  with  six 
small  muscles  for  its  motions  inserted  into  the 
outside  of  the  sclerotic  coat.  The  transparent 
cornea  through  which  the  light  is  transmitted  is 
necessarily  exposed,  and  not  being  in  its  nature 
suited  to  such  exposure,  is  covered  with  a 
membrane  called  conjunctiva,  which  also  extends 
over  the  sclerotic,  where  that  membrane  con- 
stitutes the  anterior  part  of  the  globe,  and  then 
being  reflected,  lines  the  eyelids,  and  finally  be- 
comes continuous  with  the  skin  of  the  face. 

The  human  eye  is,  as  has  been  stated  above, 
probably  a  sphere  of  about  one  inch  in  diameter. 
Petit,  however,  who  appears  to  have  first  made 
the  attempt  to  determine  the  proportions  of  the 
organ  accurately,  describes  the  axis  to  be  to  the 
diameter  as  135  to  136,  and  the  younger  S6m- 
merring,  apparently  from  his  own  observations, 
as  10  to  9.5.  This  belief  in  a  slight  differ- 
ence in  dimension  may,  however,  have  b;ei 


174 


EYE. 


adopted  from  not  making  allowance  for  the 
projection  of  the  cornea,  which  is  a  portion  of 
a  smaller  sphere  than  the  globe  itself,  and  con- 
sequently projects  beyond  its  circumference. 
From  the  flaccid  state  of  the  eye  even  shortly 
after  death,  it  must  be  very  difficult  to  measure 
it  accurately.  The  question  is,  however,  for- 
tunately of  little  practical  importance.  The 
eyeball  of  the  male  is  generally  a  little  larger 
than  that  of  the  female  ;  and  if  a  close  inquiry 
be  made  into  the  matte  .  .,  much  difference  in  this 
respect  might  probably  be  detected  in  different 
individuals.  I  have  seen  the  eyeball  in  an 
adult  of  full  size  not  larger  than  that  of  a  child 
of  five  years  old  ;  and  there  is  much  apparent 
difference  in  consequence  of  the  difference  in 
the  depth  of  the  orbit,  and  in  the  gape  of  the 
eyelids.  Although  the  human  eyeball  is  nearly 
a  perfect  sphere,  that  precise  form  is  obviously 
not  an  essential  requisite  in  the  construction  of 
a  perfect  organ  of  vision.  In  all  the  vertebral 
animals  the  bottom  of  the  eye,  where  the  retina 
is  expanded,  is  probably  a  portion  of  a  correct 
sphere,  but  in  many  the  anterior  part  is  com- 
pressed, or  in  other  words  the  sphere  is  trun- 
cated, to  adapt  it  to  the  form  and  dimensions  of 
the  head,  or  to  bring  the  cornea  and  lens  nearer 
to  the  retina.  In  the  mysticete  whale  the  axis 
is  to  the  diameter  as  20  to  29  ;  in  the  swan  as 
7  to  10  ;  in  the  turtle  as  about  8  to  10 ;  and  in 
the  cod  as  14  to  17.  This  deviation  from  the 
spherical  form  demands  a  corresponding  provi- 
sion in  the  construction  of  the  sclerotic,  to  be 
noticed  when  describing  that  membrane.  For 
a  fuller  account  of  the  comparative  proportional 
measurements  of  the  eye,  the  student  is  referred 
to  the  works  of  Cuvier  and  D.  W.  Sommer- 
ring,  as  quoted  at  the  end  of  this  article ;  the 
limits  of  which  do  not  admit  of  a  greater  detail 
of  facts  derived  from  comparative  anatomy 
than  the  illustration  of  the  description  of  the 
human  organ  absolutely  demands. 

Having  attempted  to  give  a  general  notion 
of  the  mechanism  of  the  eye  in  the  preceding 
paragraphs,  it  remains  to  consider  each  com- 
ponent part  separately,  and  to  determine  its 
organization,  properties,  and  application,  as 
well  as  the  changes  to  which  it  is  liable  from 
age,  disease,  or  other  circumstances. 

Of  the  sclerotic  membrane.  —  This,  as  has 
been  stated,  constitutes,  with  the  transpa- 
rent cornea,  the  external  case  upon  which 
the  integrity  of  the  more  delicate  inter- 
nal parts  of  the  organ  depends,  otherwise  in- 
capable of  preserving  their  precise  relations  to 
each  other :  without  such  support  the  compo- 
nent structures  must  fall  to  pieces,  or  be  crushed 
by  external  pressure.  The  name  is  derived 
from  the  Greek  cntM^ou,  and  it  has  also  been 
called  cornea  and  cornea  opaca  in  contradistinc- 
tion to  the  true  or  transparent  cornea,  a  structure 
to  which  it  bears  no  resemblance  whatsoever ; 
it  is  the  same  animal  material  which  exists  in 
all  parts  of  the  body  where  strength  with  flexi- 
bility is  required,  the  material  which  in  modern 
times  has  been  denominated  fibrous  mem- 
brane. When  carefully  freed  from  all  ex- 
traneous matter  by  clipping  with  a  pair  of 
scissors  under  water,  it  presents  the  brilliant 
silvery-white  appearance  so  characteristic  of 


the  fibrous  membranes.  The  white  streaks 
which  give  the  fibrous  appearance  appeal'  ar- 
ranged concentrically  as  the  lines  on  imper- 
fectly polished  metallic  surfaces.  It  is  inelastic 
as  other  fibrous  membranes,  and  so  strong  that 
it  does  not  tear  or  yield  unless  exposed  to  the 
greatest  violence.  Although  penetrated  by  the 
vessels  going  into  and  returning  from  the  in- 
ternal parts  of  the  eye,  it  does  not  appear  to 
have  much  more  red  blood  circulating  through 
its  texture  than  other  tendinous  expansions 
distinguished  for  their  whiteness.  The  vas- 
cularity of  the  anterior  part,  however,  where  it 
is  exposed  in  the  living  body,  constituting  the 
tunica  albuginea,  or  while  of  the  eye,  is 
different  from  that  of  the  rest  of  the  mem- 
brane. The  four  straight  muscles  are  pene- 
trated by  small  branches  of  the  ophthalmic 
artery,  the  delicate  ramifications  of  which  con- 
verge to  the  circumference  of  the  cornea,  for 
the  nutrition  of  which  membrane  they  appear 
to  be  destined.  In  the  natural  state  they  can 
scarcely  be  detected,  but  when  enlarged  by  in- 
flammation, present  a  remarkable  appearance, 
considered  by  practical  writers  one  of  the  most 
characteristic  symptoms  of  inflammation  of  the 
eyeball,  or,  as  it  is  called,  iritis.  They  then 
appear  as  numerous  distinct  vessels,  and  as  they 
approach  the  margin  of  the  cornea,  become  so 
minute  and  subdivided,  that  they  can  no  longer 
be  distinguished  as  separate  vessels,  but  merely 
present  a  uniform  red  tint,  described  as  a  pink 
zone.  The  colour  of  this  inflammatory  vascula- 
rity is  also  characteristic.  Whether  from  the 
vessels  being  more  arterial  than  venous,  or 
from  their  distribution  in  so  white  a  structure, 
they  present  a  brilliant  pink  appearance  very 
different  from  the  deep  red  of  conjunctival  in- 
flammation, which  often  enables  the  practi- 
tioner to  pronounce  an  opinion  as  to  the  nature 
of  the  disease  before  he  makes  a  close  examin- 
ation. 

The  inner  surface  of  the  sclerotic  where  it 
is  in  contact  with  the  choroid,  does  not  present 
the  same  brilliant  silver-white  appearance  that 
it  does  externally,  being  stained  with  the  black 
colouring  matter  ;  it  is  also  obscured  by  a  thin 
layer  of  cellular  membrane,  by  means  of  which 
it  is  united  to  the  external  surface  of  the  cho- 
roid.* This  layer  of  cellular  membrane  was 
described  by  Le  Cat,  and  more  particularly  by 
Zinn,  as  a  distinct  membrane,  and  considered 
to  be  a  continuation  of  the  pia  mater  ;  it  is,  how- 
ever, obviously  nothing  more  than  the  connect- 
ing material  applied  here  as  in  other  parts  of 
the  body  where  union  is  requisite. 

The  thickness  of  the  sclerotic  is  greater  m 
the  bottom  of  the  eye  than  at  its  anterior  part, 
where  it  is  so  thin  that  it  allows  the  black  colour 
of  the  choroid  to  appear  through  it,  giving  to  this 
part  of  the  eye  a  blue  tint,  particularly  remark- 
able in  young  persons  of  delicate  frame.  The  at- 
tachments of  the  four  straight  muscles,  how- 
ever, appear  to  increase  the  thickness  in  this 

*  [Arnold  and  others  describe  and  figure  a  serous 
membrane  in  this  situation  ( Spiunwebenhaut ,  arach- 
noidal nculi).  See  the  figure  of  a  vertical  section 
of  the  eye  in  Arnold  uber  das  Auge,  tab.  iii.  fig.  2, 
and  copied  into  Mr.  Mackenzie's  work  on  the 
Eye. — Ed.] 


EYE. 


175 


situation ;  but  that  there  is  no  general  thick- 
ening in  this  part  from  this  cause  is  proved 
by  the  thinness  of  the  membrane  in  the  inter- 
vals between  and  beneath  these  tendons.  The 
consequence  of  this  greater  thinness  of  the 
membrane  anteriorly  is,  that  when  the  eyeball 
is  ruptured  by  a  blow,  the  laceration  takes 
place  at  a  short  distance  from  the  cornea.  In 
animals  in  whom  the  eyeball  deviates  much 
from  a  true  sphere,  as  in  the  horse,  ox,  sheep, 
and  above  all,  in  the  whale,  the  sclerotic  is 
much  thicker  posteriorly  than  anteriorly,  being 
in  the  latter  animal  from  three  quarters  to  an 
inch  in  thickness,  while  it  is  not  more  than  a 
line  at  its  junction  with  the  cornea.  The  rea- 
son for  the  existence  of  this  provision  is,  that 
the  form  of  the  perfect  sphere  is  preserved  by 
the  uniform  resistance  of  the  contents,  but  when 
these  contents  are  spherical  in  one  part,  and 
flattened  in  another,  the  external  case  must  pos- 
sess strength  sufficient  to  preserve  this  irregu- 
larity of  form.  It  is  remarkable  that  this 
strength  is  conferred  in  the  class  mammalia 
by  giving  to  the  sclerotic  increase  of  thickness, 
the  fibrous  structure  remaining  nearly  the  same 
in  its  nature,  while  in  birds,  reptiles,  and  fishes, 
the  requisite  strength  is  derived  from  the  pre- 
sence of  a  cartilaginous  cup  or  portion  of  sphere, 
disposed  within  a  very  thin  fibrous  sclerotic. 
This  cartilaginous  sclerotic,  as  it  is  often 
called  in  the  books,  exists,  as  far  as  1  have  been 
able  to  ascertain,  in  these  three  classes,  and  is  in 
some  individuals  very  remarkable.  In  birds  it 
is  thin  and  flexible,  giving  a  degree  of  elasticity, 
which  distinguishes  the  eyeball  in  this  class. 
In  fishes,  as  has  been  observed  by  Cuvier  and 
others,  the  cartilage  is  always  present,  and  is 
particularly  thick  in  the  sturgeon ;  it  is  even 
osseous  in  some,  as  the  sea-bream,  from  the 
eye  of  which  animal  I  have  often  obtained  it 
in  the  form  of  a  hard  crust  by  putrefactive 
maceration.  Among  the  reptiles  the  turtle 
presents  a  good  example  of  this  structure. 
Where  the  deviation  from  the  spherical  form  is 
very  great,  as  in  birds,  additional  provision  is 
made  to  sustain  the  form  of  the  organ.  This 
consists  of  a  series  of  small  osseous  plates  ar- 
ranged in  a  circle  round  the  margin  of  the  cor- 
nea, lapping  over  each  other  at  the  edges,  and 
intimately  connected  with  the  fibrous  and  car- 
tilaginous layers  of  the  sclerotic.  A  similar 
provision  exists  in*  the  turtle,  and  also  in  the 
chameleon,  and  many  other  lizards,  but  not 
perhaps  so  neatly  and  perfectly  arranged  as  in 
birds.  It  is  found  in  the  great  fossil  reptiles 
Ichthyosaurus  and  Plesiosaurus. 

The  sclerotic,  like  other  fibrous  membranes, 
being  inelastic  and  unyielding,  does  not  be- 
come stretched  when  fluids  accumulate  in  the 
eyeball  in  consequence  of  inflammation,  or  in 
other  words,  the  eyeball  does  not  become  en- 
larged from  effusion  of  serum  or  secretion  of 
purulent  matter  into  its  chambers.  To  this 
probably  may  be  attributed  the  intolerable 
torture  and  sense  of  tension  experienced  when 
the  eyeball  suppurates,  as  well  as  the  severe 
pain  extending  to  the  temple  in  some  forms  of 
inflammation.  The  pain  in  such  cases  must 
not,  however,  be  wholly  attributed  to  this  dis- 
tension of  an  unyielding  membrane.  The 


fibrous  membranes  in  general,  when  affected  by 
rheumatic  or  arthritic  inflammation,  become 
acutely  sensible,  and  the  cause  of  much  suffer- 
ing ;  and  the  sclerotic,  when  similarly  affected, 
acquires  the  same  description  of  painful  sen- 
sibility, apparently  independent  of  distension 
from  effusion.  In  certain  forms  of  inflam- 
mation and  other  morbid  changes  of  the 
eyeball,  the  sclerotic  appears  to  yield  to 
distension,  as  in  scrofulous  inflammation  and 
hydrophthalmia  ;  but  this  is  not  a  mechanical 
stretching,  but  an  alteration  in  structure  at- 
tended witli  a  thinning  of  the  membrane,  and 
consequent  alteration  in  the  shape  of  the  globe. 
It  appears  that  the  cornea  and  sclerotic  are 
peculiarly,  if  not  in  many  instances  almost  ex- 
clusively, the  seat  of  the  disease  in  chronic 
scrofulous  inflammation  of  the  eyeball.  This 
inference  may,  I  think,  be  justly  drawn  from 
the  fact,  that  in  such  cases  the  sclerotic  becomes 
so  much  thinned  that  the  dark  choroid  projects 
in  the  form  of  a  tumour,  and  the  eye  loses  its 
spherical  form  ;  yet  the  pupil  remains  regular, 
the  lens  transparent,  and  the  retina  sensible  to 
light.  When  the  cornea  is  destroyed  by  slough 
or  ulceration  in  severe  ophthalmia,  allowing 
the  lens  and  more  or  less  of  the  vitreous  hu- 
mour to  escape,  the  sclerotic  does  not  accom- 
modate itself  to  the  diminished  contents  by  a 
uniform  contraction,  but  merely  falls  in  ;  and 
when  the  eye  has  been  completely  emptied,  it 
is  found  many  years  after  the  injury  folded  up 
into  a  small  irregular  mass  in  the  bottom  of  the 
orbit.  When  the  organization  of  the  eye  is 
completely  destroyed  by  idiopathic,  rheumatic, 
or  syphilitic  inflammation,  the  sclerotic  becomes 
flaccid,  and  the  whole  eyeball  soft,  allovfing 
the  contraction  of  the  four  straight  muscles  to 
produce  corresponding  depressions,  and  thus 
convert  the  sphere  into  a  form  somewhat  cu- 
bical. 

Of  the  cornea. — This  is  the  transparent  body 
which  fills  the  circular  aperture  in  the  anterior 
part  of  the  spherical  sclerotic;  it  is  called  cornea 
from  its  supposed  resemblance  to  transparent 
horn, and  cornea  transparent  in  contradistinction 
to  the  sclerotic,  which,  as  has  been  stated,  is 
called  cornea  opaca.  It  is  generally  described 
as  a  transparent  structure,  serving  to  the  eye  the 
same  purpose  as  the  crystal  to  the  watch ;  but 
this  is  not  a  correct  comparison  :  the  crystal 
merely  transmits  the  light  without  changing 
the  direction  of  the  rays  ;  the  cornea,  whether 
it  be  considered  in  itself  a  lens,  or  as  the  sphe- 
rical surface  of  the  aqueous  humour,  refracts 
the  rays  and  causes  them  to  converge  to  a 
focus.  Haller,  although  he  does  not  directly 
say  that  it  is  a  lens,  yet  states  that  if  held  over 
■a  book  it  magnifies  the  letters,  which  of  course 
results  from  its  lenticular  form ;  and  Cuvier 
and  Biot  distinctly  call  it  a  meniscus.  On  the 
other  hand,  the  Sommerrings,  both  father  and 
son,  describe  it  as  a  mere  segment  of  a  sphere, 
the  curve  of  the  convexity  corresponding  to 
that  of  the  concavity,  as  in  the  watch  crystal. 
I  consider  it  to  be  a  lens  and  a  meniscus.  If 
it  be  removed  from  the  eye  a  short  time  after 
death  with  a  portion  of  the  sclerotic,  and  dipped 
in  water  to  smooth  its  surfaces,  it  magnifies  ob- 
jects when  held  between  them  and  the  eye,  as 


176 


EYE. 


stated  by  Haller ;  and  sections  of  the  cornea  of 
the  eye  of  the  horse,  ox,  sheep,  or  other  large 
animals,  shew  that  the  part  is  much  thicker  in 
the  centre  than  at  the  circumference.  It  is 
also  to  be  observed  that  it  has  the  same  provi- 
sion for  the  preservation  of  its  lenticular  form 
in  a  correct  state  as  the  crystalline  lens,  as  will 
presently  be  explained.  The  statements  made 
by  authors  respecting  the  measurements  of 
the  curvatures  of  the  surface  of  the  cornea  can 
be  considered  only  as  an  approximation  to  the 
truth.  It  is  obvious  that  there  must  be  much 
difficulty  in  accurately  ascertaining  the  matter 
during  life,  and  after  death  the  form  is  so 
speedily  altered  by  evaporation  that  the  curve 
cannot  remain  the  same  as  during  life,  hence 
the  measurements  differ.  Haller  says  it  is  a 
portion  of  a  sphere  seven  lines  and  a  half 
in  diameter;  Wintringham  that  the  chord  is 
equal  to  1.05  of  an  inch,  the  versed  sine  of 
this  chord  0.29,  and  consequently  the  radius  is 
equal  to  0.620215  of  an  inch.  Mr.  Lloyd,  in 
his  Optics,  states,  on  the  authority  of  Chossat, 
that  the  surface  of  the  cornea  is  not  spherical 
but  spheroidical.  He  says,  "  the  bounding 
surfaces  of  the  refracting  media,  however,  are 
not  spherical  but  spheroidical.  This  remark- 
able fact  was  long  since  suspected  by  M.  Petit, 
but  of  late  has  been  placed  on  the  clearest 
evidence  by  the  accurate  measurements  of 
Chossat.  This  author  has  found  that  the 
cornea  of  the  eye  of  the  ox  is  an  ellipsoid  of 
revolution  round  the  greater  axis,  this  axis 
being  inclined  inwards  about  10°.  The  ratio 
of  the  major  axis  to  the  distance  between  the 
foci  in  the  generating  ellipse  he  found  to  be 
1.3;  and  this  agreeing  very  nearly  with  1.337, 
the  index  of  refraction  of  the  aqueous  humour, 
it  follows  .that  parallel  rays  will  be  refracted  to 
a  focus  by  the  surface  of  this  humour  with  ma- 
thematical accuracy."  Whether  we  consider 
the  cornea  as  a  distinct  lens,  or  as  constituting 
the  spherical  surface  of  the  aqueous  humour, 
there  can  be  no  doubt  of  its  importance  as  an 
agent  in  causing  the  convergence  of  the  rays  of 
light  to  a  focus  on  the  retina  in  conjunction 
with  the  crystalline  lens.  If  other  proof  were 
wanted,  it  is  afforded  by  the  comparatively 
perfect  optical  mechanism  of  the  eye  after  the 
crystalline  lens  has  been  removed  by  the  opera- 
tion for  cataract.  The  vision  in  such  cases, 
especially  in  young  persons,  is  often  so  good 
that  individuals  are  satisfied  with  it  for  the 
common  purposes  of  life,  and  do  not  resort  to 
the  use  of  the  usual  convex  glasses.  The  cir- 
cumference of  the  cornea  is  not  perfectly  cir- 
cular externally,  although  it  is  internally;  the 
sclerotic  laps  a  little  over  it  both  superiorly  and 
inferiorly,  so  that  it  appears  a  little  wider  than 
it  is  deep,  the  vertical  being  to  the  horizontal 
diameter  as  fifteen  to  sixteen. 

Although  the  cornea  is  in  general  description 
considered  a  simple  and  uniform  membrane, 
it  is  undoubtedly  composed  of  three  forms  of 
animal  structure,  as  different  from  each  other  as 
any  other  three  in  the  animal.  These  are  the 
conjunctiva,  which  constitutes  the  exposed  sur- 
face ;  the  proper  cornea,  upon  which  the 
strength  of  the  part  depends ;  and  the  elastic 
cornea,  which  lines  the  inner  concave  surface. 


The  conjunctiva  is  evidently  a  continuation  of 
the  skin,  which,  reflected  in  the  form  of  a  vas- 
cular membrane,  lines  the  eyelids,  from  which 
it  is  continued  as  a  delicate  transparent  mem- 
brane over  the  anterior  part  of  the  globe,  ad- 
hering loosely  to  the  sclerotic,  and  closely  to 
the  cornea.  The  existence  of  conjunctiva  on 
the  surface  of  the  cornea  proper  admits  of  easy 
demonstration,  and  its  identity  of  character 
with  the  rest  of  the  conjunctiva  and  skin  of 
satisfactory  proof.  If  the  surface,  shortly  after 
death,  be  scraped  with  the  point  of  a  needle, 
the  soft  texture  of  the  conjunctiva  is  easily  torn 
and  detached,  and  the  tough,  firm,  polished 
surface  of  the  cornea  proper  exposed ;  and  if 
the  eye  be  allowed  to  remain  for  forty-eight 
hours  in  water,  the  whole  layer  may  by  a  little 
care  be  turned  off  in  the  form  of  a  distinct 
membrane.  During  life,  patches  of  the  con- 
junctiva are  frequently  scraped  off  by  accident, 
or  by  the  point  of  the  needle  of  the  surgeon  as 
he  attempts  to  remove  foreign  bodies  implanted 
in  the  cornea  proper;  it  is  also  occasionally  ac- 
cidentally removed  by  lime  or  other  escharotics. 
When  the  vessels  of  the  conjunctiva  over  the 
sclerotic  become  enlarged,  and  filled  with  red 
blood  in  consequence  of  preceding  inflamma- 
tion, that  over  the  cornea  at  length  becomes 
equally  red,  and  has  its  transparency  greatly 
impaired  by  the  vascular  ramifications.  •  In 
pustular  ophthalmia,  the  pustules  form  on  the 
conjunctiva  over  the  cornea  as  well  as  on  that 
over  the  sclerotic ;  and  in  small-pox,  vision  is 
frequently  destroyed  by  this  part  of  the  tegu- 
mentary  membrane  participating  in  the  general 
disease.  In  cases  where  the  surface  is  con- 
stantly exposed  to  the  atmosphere  in  conse- 
quence of  prominent  staphyloma  or  destruc- 
tion or  eversion  of  the  eyelids,  the  conjunctiva 
of  the  cornea  occasionally  becomes  covered 
with  cuticle  in  common  with  the  rest  of  the 
membrane.  In  animals  over  whose  eyes  the 
skin  is  continued  without  forming  eyelids,  the 
continuity  of  it  over  the  cornea  is  obvious.  In 
the  mole-rat  ( Aspalax  xemni.),  where  the  skin 
is  uninterruptedly  continued  over  the  eye,  the 
hairs  grow  from  the  part  over  the  cornea  as 
well  as  from  the  rest.  When  snakes  cast  their 
covering,  the  cuticle  is  detached  from  the 
cornea  as  well  as  from  the  rest  of  the  body; 
and  when  the  skin  is  drawn  off  the  body  of  an 
eel,  it  is  detached  with  equal  ease  from  the 
cornea  as  from  the  rest  of  the  eye. 

The  cornea  proper,  upon  which  the  strength 
of  this  part  of  the  eye  depends,  is  the  structure 
to  which  the  appellation  cornea  is  generally 
exclusively  applied ;  it  is,  as  might  very  rea- 
sonably be  expected  from  the  office  which  it 
performs,  a  material  of  peculiar  nature  and 
organization,  not  identical  with  any  other  of 
the'  simple  membranes.  During  life,  and 
before  it  becomes  altered  by  the  changes  which 
take  place  after  death,  it  is  perfectly  trans- 
parent, colourless,  and  apparently  homoge- 
neous. This  perfect  transparency,  however, 
depends  upon  the  peculiar  relation  of  the 
component  parts  of  its  texture,  for  if  the  eye- 
ball of  an  animal  recently  dead  be  firmly 
squeezed,  the  cornea  is  rendered  completely 
opaque,  by  altering  that  relation  of  parts,  and 


EYE. 


177 


as  speedily  recovers  its  transparency  upon  the 
removal  of  the  pressure.  The  chemical  com- 
position of  the  cornea  is  similar  to  that  of  the 
fibrous  membranes  in  general  and  the  sclerotic 
in  particular :  like  the  latter  structure,  it  is  con- 
verted into  gelatine  by  boiling ;  but  Berzelius 
states  that  it  contains  also  a  small  quantity  of 
fibrine  or  coagulated  albumen,  as  proved  by 
the  formation  of  a  precipitate  upon  adding  the 
cyanuret  of  ferro-prussiate  of  potass  to  acetic 
acid,  in  which  the  membrane  has  been  digested. 
The  cornea  possesses  great  strength,  being 
seldom  or  never  ruptured  by  blows  on  the  eye- 
ball, which  frequently  tear  the  sclerotic  exten- 
sively. It  does  not  yield  to  distension  from 
increased  secretion,  effusion,  or  suppuration 
within  the  eyeball  in  consequence  of  inflam- 
mation, but  it  becomes  extended  and  altered 
by  growth  both  in  shape  and  dimensions,  as 
may  be  observed  in  prominent  staphyloma, 
lvydrophthalmia,  and  that  peculiar  alteration 
called  staphyloma  pellucidum,  in  which  the 
spherical  form  of  the  membrane  degenerates 
into  a  cone,  but  retains  its  transparency. 

The  cornea  is  destitute  of  red  vessels,  yet  it 
affords  a  signal  example  of  colourless  and 
transparent  texture  possessing  vital  powers 
inferior  to  no  other.  No  structure  in  the  body 
appears  more  capable  of  uniting  by  the  first 
intention.  The  wound  inflicted  in  extracting  a 
cataract  is  often  healed  in  forty-eight  hours,  yet 
the  lips  are  bathed  internally  with  the  aqueous 
humour,  and  externally  with  the  tears.  Ulcers 
fill  up  and  cicatrize  upon  its  surface ;  and  al- 
though the  vessels,  under  such  circumstances, 
frequently  become  so  much  enlarged  as  to 
admit  red  blood,  yet  there  can  be  no  doubt 
that  ulcers  do  heal  without  a  single  red  vessel 
making  its  appearance.  Abscesses  form  in  the 
cornea,  and  contain  purulent  matter  of  the 
same  appearance  as  elsewhere ;  they  are  gene- 
rally said  to  be  between  the  layers  of  the 
cornea,  but  they  are  evidently  distinct  cavities 
circumscribed  by  the  inflammatory  process  as 
i.  ^her  cases;  occasionally,  however,  the 
whole  texture  of  the  cornea  becomes  infil- 
trated with  purulent  matter,  as  the  cellular 
membrane  in  erysipelas.  The  rapidity  with 
which  this  membrane  is  destroyed  by  the  ul- 
cerative process  is  another  proof  of  its  superior 
vitality.  In  a  few  days  a  mere  speck  of  ulce- 
ration, the  consequence  of  a  pustule,  extends 
through  the  entire  thickness,  and  permits  the 
iris  to  protrude;  and  in  gonorrhoeal  and  infantile 
purulent  ophthalmia,  the  process  is  much  more 
rapid  and  extensive.  It  is  true  that  in  the 
latter  case  the  destruction  is  attributed  to  gan- 
grene or  sloughing,  and  to  a  certain  extent 
correctly;  but  an  accurate  observer  must  admit 
that  the  two  processes  co-operate  in  the  pro- 
duction of  the  lamentable  consequences  which 
result  from  these  diseases.  Ulcers  of  the  cornea 
fill  up  by  granulation  and  cicatrize  as  in  other 
parts  of  the  body,  but  the  repaired  part  does 
not  possess  the  original  organization,  and  is 
consequently  destitute  of  that  transparency  and 
regularity  of  surface  so  essential  for  its  func- 
tions ;  hence  the  various  forms  and  degrees  of 

VOL.  II. 


opacity  enumerated  under  the  technical  titles 
of  albugo,  leucoma,  margarita,  nebula,  &c. 
which  are  probably  never  remedied,  however 
minute  they  may  be,  notwithstanding  the  ge- 
neral reliance  placed  in  the  various  stimulating 
applications  made  for  this  purpose.  Slight 
opacities,  or  nebula  as  they  are  called,  if  con- 
fined to  the  conjunctival  covering  of  the  cornea, 
gradually  disappear  after  the  inflammation  sub- 
sides, as  does  also  diffused  opacity  of  the 
cornea  itself,  the  consequence  of  scrofulous 
inflammation ;  but  I  believe  opacities  from 
ulceration  and  cicatrix  are  seldom  if  ever  re- 
moved. The  effect  of  acute  inflammation  is 
to  render  this,  and  perhaps  all  transparent  and 
colourless  membranes,  white  and  opaque  with- 
out producing  redness ;  this  may  be  seen  in 
wounds,  where  the  edges  speedily  become 
gray ;  and  in  the  white  circle  which  frequently 
occupies  the  margin  of  the  cornea  in  the  in- 
flammations of  the  eyeball  commonly  called 
iritis. 

The  cornea  in  a  state  of  health  is  destitute 
of  sensibility.  Of  this  I  have  frequently  sa- 
tisfied myself  by  actual  experiment  in  cases  of 
injury  of  the  eye,  where  the  texture  of  the  part 
is  exposed.  When  foreign  bodies,  such  as 
specks  of  steel  or  other  metals,  are  lodged  in 
its  structure,  the  surgeon  experiences  much  dif- 
ficulty in  his  attempts  to  remove  them,  from 
the  extremely  painful  sensibility  of  the  con- 
junctiva as  he  touches  it  with  his  needle  ;  but 
the  moment  he  strikes  the  point  of  the  instru- 
ment beneath  the  foreign  body  into  the  cornea 
itself,  the  eye  becomes  steady,  and  he  may 
touch,  scrape,  or  cut  any  part  of  the  membrane 
uncovered  by  conjunctiva  without  complaint. 

It  has  already  been  stated  that  the  cornea, 
as  it  constitutes  the  transparent  medium  for 
the  passage  of  the  rays  of  light,  is  composed  of 
three  distinct  forms  of  structure  altogether  dif- 
ferent from  each  other,  the  conjunctiva,  the 
cornea  proper,  and  the  elastic  cornea.  The 
latter  membrane  is  now  to  be  described.  In 
many  of  our  books  this  membrane  is  vaguely 
alluded  to  as  the  membrane  of  the  aqueous 
humour  ;  but  with  this  it  must  not  for  a  mo- 
ment be  confounded.  It  is  a  distinct  provision 
for  a  specific  purpose,  totally  different  from 
that  for  which  the  other  is  provided.  It  was 
known  to  and  described  by  Duddell,  Decemet, 
Demours,  and  latterly  by  Mr.  Sawrey  ;  but  all 
these  authors  having  unfortunately  published 
their  accounts  in  separate  and  probably  small 
treatises,  not  preserved  in  any  journal,  I  have 
not  been  able  to  consult  them.  It  is,  however, 
distinctly  recognized  by  Clemens,  D.  W. 
Sommerring,  Blainville,  and  Hegar ;  and  in  a 
paper  on  the  anatomy  of  the  eye  in  the  Me- 
dico-Chirurgical  Transactions,  I  endeavoured  to 
direct  attention  to  it  without  effect.  The  struc- 
ture here  alluded  to  is  a  firm,  elastic,  exqui- 
sitely transparent  membrane,  exactly  applied  to 
the  inner  surface  of  the  cornea  proper,  and  se- 
parating it  from  the  aqueous  humour.  When 
the  eye  has  been  macerated  for  a  week  or  ten 
days  in  water,  by  which  the  cornea  proper  is 
rendered  completely  opaque,  this  membrane  re- 

N 


178 


EYE. 


tains  its  transparency  perfectly  ;  it  also  retains 
its  transparency  after  long-continued  immersion 
in  alcohol,  or  even  in  boiling  water.  When 
detached,  it  curls  up  and  does  not  fall  flaccid 
or  float  loosely  in  water,  as  other  delicate  mem- 
branes. It  also  presents  a  peculiar  sparkling- 
appearance  in  water,  depending  upon  its  greater 
refractive  power;  in  fact  it  presents  all  the 
characters  of  cartilage,  and  is  evidently  of  pre- 
cisely the  same  nature  as  the  capsule  of  the 
crystalline  lens.  When  the  cornea  proper  is 
penetrated  by  ulceration,  a  small  vesicular  trans- 
parent prominence  has  been  repeatedly  ob- 
served in  ihe  bottom  of  the  ulcer,  confining  for 
a  time  the  aqueous  humour,  but  ultimately 
giving  way,  and  allowing  that  fluid  to  escape, 
and  the  iris  to  prolapse;  there  can  be  little 
doubt  that  it  is  this  membrane  which  presents 
this  appearance.  In  syphilitic  iritis,  this  mem- 
brane becomes  partially  opaque,  appearing 
d  usted  or  speckled  over  with  small  dots  altogether 
different  in  appearance  from  any  form  of 
opacity  observed  on  the  conjunctiva  or  cornea 
proper.  When  it  has  been  touched  by  the 
point  of  the  needle  in  breaking  up  a  cataract, 
an  opacity  is  produced  closely  resembling  cap- 
sular cataract.  There  is  no  difficulty  in  pre- 
paring and  demonstrating  this  membrane  in  the 
eye  of  the  sheep,  ox,  and  especially  the  horse, 
and  it  may  with  a  little  care  be  exhibited  in  the 
human  and  other  smaller  eyes.  The  eye  of 
a  horse  having  been  macerated  in  water  for  six 
or  eight  days,  or  until  the  cornea  proper  be- 
comes white,  should  be  grasped  in  the  left  hand 
so  as  to  render  the  anterior  part  plump,  and 
then  inserting  the  point  of  a  sharp  knife  into 
the  structure  of  the  cornea  at  its  junction  with 
the  scleiotic,  layer  after  layer  should  be  gra- 
dually divided  by  repeated  touches  round  the 
circumference,  until  the  whole  thickness  is  cut 
through  and  the  transparent  elastic  cornea  ap- 
pears, after  which  the  cornea  proper  may  be 
turned  off  by  pulling  it  gently  with  the  forceps. 
The  use  of  the  elastic  cornea  does  not  appear 
to  me  doubtful.  The  crystalline  lens  is  lodged 
in  a  capsule  of  precisely  the  same  nature,  evi- 
dently destined  to  preserve  correctly  the  curva- 
ture of  each  surface  of  that  body,  a  condition 
obviously  necessary  to  secure  the  perfection  of 
the  optical  mechanism  of  the  organ.  The 
elastic  cornea  in  the  same  way,  by  its  firmness, 
resistance,  and  elasticity,  preserves  the  requi- 
site permanent  correct  curvature  of  the  flaccid 
cornea  proper. 

The  cornea  proper  is  closely  and  intimately 
connected  to  the  sclerotic  at  its  circumference. 
There  does  not  appear  to  be  any  mechanical 
adaptation  resembling  the  fitting  of  a  watch-glass 
into  the  bezel,  as  stated  in  books;  but  a  ming- 
ling of  texture,  as  in  many  other  instances  in  the 
body.  The  two  structures  cannot  be  separated 
without  anatomical  artifice  and  much  vio- 
lence. If  the  eye  be  macerated  in  water  for  a 
month,  and  then  plunged  into  boiling  water, 
the  cornea  may  be  torn  from  the  sclerotic  ;  but 
these  destructive  processes  prove  little  with  re- 
gard to  animal  organization.  The  conjunctival 
covering  of  the  cornea  is,  as  has  been  already 


stated,eontinuouswith  the  rest  of  the  conjunctiva, 
and  the  elastic  cornea  is  continued  for  a  short 
distance  beneath  the  sclerotic,  as  if  slipped  in 
between  it  and  the  ciliary  ligament. 

The  cornea,  thus  composed  of  three  different 
structures,  varies  in  appearance  at  different 
periods  of  life.  In  the  fetus  at  birth  it  is 
slightly  cloudy,  and  even  of  a  pinkish  tint,  as 
if  it  contained  some  red  particles  in  its  blood  ; 
this  is,  however,  more  apparent  on  examination 
after  death  than  during  life  ;  it  is  also  thicker 
in  its  centre.  In  old  age  it  is  harder,  tougher, 
and  less  transparent  than  in  youth,  and  fre- 
quently becomes  completely  opaque  at  its  cir- 
cumference, presenting  the  appearance  denomi- 
nated in  the  books  arcus  senilis.  How  far  the 
alteration  in  the  power  of  adaptation  to  distance, 
which  occurs  in  advanced  life,  is  to  be  attri- 
buted to  change  in  curvature  of  the  cornea,  is 
not  settled. 

If  the  foregoing  account  be  correct,  the  ap- 
parently simple  transparent  body  which  fills  the 
aperture  in  the  anterior  part  of  the  sclerotic,  is 
composed  of  three  distinct  varieties  of  organic 
structure,  liable  to  changes  from  disease  equally 
distinct  and  varied.  When  the  aqueous  hu- 
mour becomes  the  subject  of  description,  I 
will  endeavour  to  shew  that  there  is  good  rea- 
son for  believing  that  a  fourth  may  be  added  to 
these  three,  the  membrane  which  lines  the 
chamber  in  which  this  fluid  is  lodged,  and  by 
which  it  is  secreted.  Let  it  not  be  supposed 
that  this  division  of  an  apparently  simple  piece 
of  organization  into  so  many  distinct  parts,  is 
merely  an  exhibition  of  minute  anatomical  re- 
finement. The  distinction  is  essentially  neces- 
sary to  enable  the  surgeon  to  account  for  the 
appearances  produced  by  disease  in  this  part, 
and  to  guide  him  in  the  diagnosis  and  treat- 
ment. 

Of  the  choroid  coat. — This  membrane  has 
been  so  called  from  its  supposed  resem- 
blance to  the  chorion  of  the  gravid  uterus; 
it  has  also  sometimes  been  called  uvea  from 
its  resemblance  to  a  grape,  a  term,  howevei, 
which  is  now  more  frequently  applied  to  the 
iris.  It  has  already  been  stated  that  the 
spherical  external  case  of  the  eye  called  the 
sclerotic  embraces  another  spherically  disposed 
membrane,  called  the  choroid  coat,  accurately 
fitted  and  adhering  to  it  throughout.  This 
spherically  disposed  membrane  has  also  its  cir- 
cular aperture  anteriorly,  into  which  is  fitted 
the  screen  or  diaphragm  called  the  iris.  This 
choroid  membrane  cannot  be  considered  essen- 
tial to  the  perfection  of  the  organ  considered 
merely  as  a  piece  of  optical  mechanism,  as  a 
spherical  camera  obscura,  but  is  obviously  an 
important  part  of  its  anatomical  organization, 
and  an  essential  provision  for  the  perfection  of 
its  vital  functions.  It  appears  to  be  destined  to 
secure  the  requisite  mechanical  connexion  be- 
tween the  coarser  and  more  rigid  sclerotic  case 
and  the  parts  within,  as  well  as  to  secure  these 
delicate  parts  in  their  situation,  and  preserve 
their  form,  at  the  same  time  affording  a  me- 
dium for  the  distribution  and  support  of  the 
vessels  and  nerves.  , 


EYE. 


179 


This  membrane  is  of  a  deep  brown  or  black 
colour,  being  stained  with  the  colouring  matter 
called  the  black  pigment;  but  when  this  is 
removed,  it  exhibits  a  high  degree  of  arterial 
and  venous  vascularity.  Its  external  surface 
is  comparatively  rough,  coarse,  and  flocculent, 
and  obscured  by  the  cellular  membrane  which 
connects  it  to  the  sclerotic.  The  inner  surface, 
which  is  in  contact  with  the  retina,  presents  a 
very  different  appearance.  It  is  soft  and  smooth, 
and  when  minutely  injected,  resembles  the 
more  delicate  mucous  membranes,  and  exhibits 
a  remarkable  degree  of  minute  villous  vascu- 
larity. The  external  surface  being  composed 
of  the  larger  branches  of  arteries,  veins,  and 
nerves,  may  be  torn  away  from  the  soft,  smooth, 
and  more  closely  interwoven  inner  layer,  or 
the  inner  layer  may  be  partially  dissected  up 
from  it,  with  some  care,  especially  in  the  eyes 
of  the  larger  quadrupeds.  This  manoeuvre 
having  been  executed  by  Ruysch,  and  prepara- 
tions so  formed  displayed  by  him,  the  inner 
layer  has  been  denominated  the  tunica  Ruys- 
chiana.  But  this  is  a  mere  anatomical  artifice. 
There  is  no  natural  division  into  two  layers, 
the  soft,  smooth,  and  highly  vascular  inner 
surface  being  formed  by  the  ultimate  subdivi- 
sion and  distribution  of  the  larger  branches  of 
vessels,  which  exhibit  themselves  sepaiately  on 
the  outside.  It  is  a  condition  somewhat  analo- 
gous to  that  of  the  skin,  where  the  soft,  smooth, 
villous  external  surface  presents  so  remarkable 
a  contrast  to  the  rough  internal  surface  with  its 
layer  of  cellular  membrane  uniting  it  to  the 
subjacent  parts. 

~->The  choroid  is  supplied  with  blood  from  the 
ophthalmic  artery  by  the  short  ciliary  arteries, 
which  penetrate  the  sclerotic  at  a  short  distance 
from  the  entrance  of  the  optic  nerve,  and  are 
distributed  to  it  in  nearly  twenty  small  branches. 
These  branches  ramify  and  inosculate  freely  on 
the  outside  of  the  membrane,  and  are  visible  as 
distinct  vessels,  especially  on  the  posterior  part 
of  the  sphere.    They  finally  terminate  on  the 
inner  surface,  forming  a  beautiful  vascular 
expansion.     The  long  ciliary  arteries  give 
scarcely  any  twig  to  the  choroid,  being  distri- 
buted to  the  iris,  and  the  anterior  branches 
furnished  to  the  sclerotic,   as  described  in 
speaking  of  that  membrane,  do  not  penetrate 
to  the  choroid.    The  veins  of  the  choroid  pre- 
sent a  peculiar  appearance.    The  ramifications 
are  arranged  in  the  form  of  arches  or  portions 
of  a  circle,  bending  round  to  a  common  trunk 
like  those  of  certain  trees  with  pendulous 
branches.    They  discharge  their  blood  into 
four  or  five  larger  branches  which  penetrate 
the  sclerotic  at  nearly  equal  distances  from  each 
other  behind  the  middle  of  the  eyeball.  On 
account  of  this  peculiar  arrangement  they  have 
received  the  name  of  vasa  vorticosa.    They  lie 
external  to  the  ciliary  arteries,  but  the  ultimate 
ramifications  pervade  the  inner  surface  in  the 
same  manner  as  the  arteries ;  and  if  the  venous 
System  of  the  eye  be  minutely  injected,  the 
same  beautiful  uniform  villous  vascularity  is 
displayed  as  in  the  arterial  injections. 

The  annexed  figure  is  a  copy  of  Zinn's  re- 
presentation of  the  vasa  vorticosa. 


Fig.  104. 


The  numerous  nerves  which  pierce  the  scle- 
rotic and  run  forward  between  that  membrane 
and  the  choroid,  called  ciliary  nerves,  being 
distributed  almost  exclusively  to  the  iris,  are 
to  be  noticed  when  that  organ  is  described ; 
small  branches  of  them  are,  however,  probably 
distributed  to  the  choroid  and  its  appendages, 
and  possibly  even  to  the  retina  and  hyaloid 
membrane. 

The  inner  villous  surface  of  the  choroid, 
which  in  man  is  stained  with  the  black  pig- 
ment, in  several  other  animals  presents  a  bril- 
liant colour  and  metallic  lustre.  This  is  called 
the  tapeturn.  It  is  not  a  superadded  material  nor 
dependent  on  any  imposed  or  separable  colour- 
ing matter,  but  is  merely  a  different  condition 
of  the  surface  of  the  choroid  or  tunica  Ruvs- 
chiana,  by  means  of  which  rays  of  light  of  a 
certain  colour  only  are  reflected.  It  exists  in 
the  form  of  a  large  irregular  patch,  occupying 
the  bottom  of  the  eye  toward  the  outside  of 
the  entrance  of  the  optic  nerve.  It  is  of  a 
beautiful  blue,  green,  or  yellow  colour,  with 
splendid  metallic  lustre,  and  sometimes  white 
as  silver.  It  is  not  obscured  by  the  black 
pigment  which  covers  the  rest  of  the  surface 
and  even  encroaches  a  little  on  its  margin,  and 
consequently  it  acts  most  perfectly  as  a  concave 
reflector,  causing  the  rays  of  light  previously 
concentrated  on  the  bottom  of  the  eye  by  the 
lens  to  be  returned,  and  to  produce  that  re- 
markable luminous  appearance  observed  in  the 
eyes  of  cats  and  other  animals  when  seen  in 
obscure  situations.  This  provision  is, absent  m 
man,  the  quadrumanous  animals,  bats,  the 
insectivorous  order,  perhaps  all  the  rodentia,  the 
sloths  and  many  other  of  the  class  mammalia  ; 
while  it  is  present  in  the  majority  if  not  all  of 
the  ruminants,  as  well  as  in  the  horse,  the 
cetacea,  and  most  of  the  carnivorous  tribe.  -It 
does  not  appear  to  exist  in  birds  or  reptiles, 
and  is  absent  in  the  osseous,  although  present 
in  the  cartilaginous  fishes.  I  must  here,  how- 
ever, state  that  I  am  obliged  to  speak  loosely 
respecting  this  matter,  as  the  subject  has  not 
yet  been  thoroughly  investigated.  The  use  of 
this  tapetum  has  not  been  ascertained,  or  the 
reason  why  it  exists  in  some  and  is  absent  in 
other  animals  explained.  It  is  obvious  that 
where  it  is  present  the  rays  of  light  are  trans- 
mitted through  the  retina,  and  again  when 
reflected  by  the  tapetum  are  returned  through 
the  same  retina,  thus  twice  pervading  that 
structure. 

k  2 


180 


EYE. 


On  the  outside  and  anterior  part  of  the 
choroid,  where  the  margin  of  that  membrane 
corresponds  to  the  place  of  union  between  the 
sclerotic  and  cornea,  a  peculiar  and  distinct 
formation  exists  apparently  for  the  purpose  of 
securing  a  firm  union  between  the  two  mem- 
branes. It  is  commonly  called  the  ciliary  liga- 
ment, also  orbiculus  ciliaris,  circulus  ciliaris, 
by  Lieutaud  plexus  ciliaris,  by  Zinn  armulus 
cellulosus,  and  by  Sommerring  gangliform  ring. 
It  is  a  gray  circle  of  soft  cellular  membrane 
about  two  lines  broad,  applied  like  a  band 
round  the  margin  of  the  aperture  into  which 
the  iris  is  fitted.  It  adheres  closely  to  the 
choroid,  and  almost  equally  closely  to  the  scle- 
rotic, especially  in  the  groove  where  the  cornea 
joins  that  membrane.  It  contains  few  red 
vessels,  and  is  not  stained  by  the  black  pig- 
ment; consequently  it  is  of  a  whitish  colour. 
The  ciliary  nerves  penetrate  it  and  subdivide 
in  its  structure.  Hence  it  has  been  considered 
by  Sommerring  as  a  ganglion,  aftd  had  been 
previously  described  by  Lieutaud  as  a  nervous 
plexus.  The  ciliary  nerves,  however,  merely 
pass  through,  and  may  easily  be  traced  on  to 
the  iris.  It  is  evidently  a  mere  band  of  cellular 
membrane  serving  to  bind  the  choroid  and 
sclerotic  together  at  this  point,  and  is  obviously 
a  provision  essentially  necessary  for  the  perfec- 
tion of  the  anatomical  mechanism  of  the  eye, 
as  without  it  the  aqueous  humour  must,  from 
pressure  on  the  eyeball,  be  forced  back  be- 
tween the  two  membranes.  In  man  it  is  broader 
in  proportion  than  in  the  larger  quadrupeds, 
and  in  birds  it  is  particularly  large  and  dense, 
adhering  more  closely  to  the  circle  of  osseous 
plates  than  to  the  choroid,  and  consequently 
presents  a  very  remarkable  appearance  when 
the  latter  membrane  is  pulled  off  with  the 
ciliary  processes  and  iris,  an  appearance  to 
which  the  attention  of  anatomists  was  first 
drawn  by  Mr.  Crampton.  From  its  position 
and  appearance  the  ciliary  ligament  has  often 
been  suspected  to  be  a  muscular  organ,  destined 
by  its  contraction  to  alter  the  form  of  the  cornea, 
and  thus  adapt  the  eye  to  distance.  There  is 
not,  however,  sufficient  evidence  to  sustain 
such  an  opinion.  The  plate  introduced  to 
represent  the  ciliary  nerves,  as  well  as  that 
which  represents  the  iris,  exhibit  this  part  of 
the  organization  of  the  eyeball  in  connexion 
with  the  choroid. 

On  the  inside  of  the  choroid,  surrounding 
the  aperture  into  which  the  iris  is  fitted,  and 
corresponding  in  position  within  to  the  ciliary 
ligament  without,  exists  another  peculiar  pro- 
vision destined  to  establish  a  connexion  between 
this  part  and  the  hyaloid  membrane  of  the 
vitreous  humour,  as  the  ciliary  ligament  esta- 
blishes a  similar  connexion  between  the  sclerotic 
and  choroid.  This  is  the  corpus  ciliare  or 
ciliary  processes,  called  sometimes  incorrectly 
ciliary  ligament,  and  by  Sommerring  corona 
ciliaris.  It  is  composed  of  a  number  of  dis- 
tinct folds  or  productions  of  the  choroid,  having 
their  anterior  extremities  extended  to  the  back 
of  the  iris,  while  the  posterior  gradually  dimi- 
nish until  lost  in  the  membrane  from  which 
they  originate.    Each  fold  or  ciliary  process  is 


a  production  or  continuation  of  the  choroid, 
and  cannot  be  separated  from  it  unless  clipped 
off  by  the  scissors.  They  appear  to  be  com- 
posed altogether  of  a  remarkable  interlacement 
of  arteries  and  veins  derived  from  those  of  the 
choroid,  and  exhibit  no  appearance  whatsoever 
of  muscular  organization,  although  considered 
by  Porterfield  and  others  as  endowed  with  that 
function.  These  are  sixty  or  seventy  in  num- 
ber, fifty-seven  being  enumerated  by  Sommer- 
ring, and  seventy  by  Zinn.  They  are  about 
two  lines  in  length,  but  are  not  equally  so, 
every  alternate  one  being  shorter  than  the  next 
to  it.  The  free  internal  margin  of  each  ciliary 
process  is  buried  in  the  hyaloid  membrane  of 
the  vitreous  humour  at  its  anterior  part,  round 
the  circumference  of  the  crystalline  lens,  and  a 
corresponding  production  of  the  hyaloid  mem- 
brane projects  into  the  space  between  these 
processes  so  as  to  establish  a  most  perfect  bond 
of  union  between  the  two  structures.  The 
ciliary  processes  appear  to  be  attached  to  the 
circumference  of  the  lens,  and  are  often  de- 
scribed as  having  such  connexion.  This,  how- 
ever, is  not  the  case.  The  anterior  extremities 
do  not  touch  the  circumference  of  the  lens; 
they  project  into  the  posterior  chamber  of  the 
aqueous  humour  up  to  the  back  of  the  iris, 
and  consequently  constitute  the  circumferen- 
tial boundary  of  that  cavity.  When  the  eye 
becomes  flaccid  from  evaporation  after  death, 
the  ciliary  processes  fall  down  to  the  margin  of 
the  lens  and  appear  to  adhere  ;  but  if  the  cornea 
and  iris  be  removed  from  the  eye  of  a  subject 
recently  dead,  a  circle  of  hyaloid  membrane 
may  distinctly  be  seen  occupying  the  space 
between  the  ciliary  processes  and  lens,  through 
which  the  observer  can  see  to  the  bottom  of 
the  eye.  This  space  is  represented  and  pointed 
out  in  Sommemug's  plates.  The  annexed 
figure  from  Zinn's  work  represents  the  corpus 
ciliare  or  circle  of  ciliary  processes  on  a  large 
scale. 


Fig.  105. 


The  choroid,  in  common  with  several  other 
parts  of  the  eye  and  its  appendages,  is  stained 
by  a  black  colouring  matter  secreted  in  and 
upon  different  textures.  In  man  it  is  of  a  dark- 
brown  colour,  but  in  other  animals  is  generally 


EYE. 


181 


black,  and  so  loosely  connected  with  the  struc- 
ture in  which  it  is  deposited,  that  in  dissecting 
the  eyes  of  our  common  graminivorous  animals 
under  waterit  becomes  diffused,  and  colours  the 
fluid  as  the  ink  of  the  cuttle-fish  obscures  the 
water  into  which  it  is  shed.  It  is  not  confined 
to  any  one  particular  structure,  but  is  deposited 
in  every  situation  where  it  is  necessary  for  the 
purpose  for  which  it  is  destined.  It  is  found 
in  considerable  quantity  on  the  inner  surface  of 
the  choroid,  where  it  appears  as  if  laid  on  in 
the  form  of  a  paint,  and  is  frequently  so 
described ;  but  it  is  much  more  probable  that 
it  is  deposited  in  the  interstices  of  the  exqui- 
sitely fine  cellular  membrane  which  connects 
the  choroid  with  the  delicate  covering  of  the 
retina.  In  this  situation  it  often,  especially  in 
infants,  presents  the  appearance  of  a  perfectly 
distinct  black  membrane,  which  may  be  peeled 
off  in  flakes  or  allowed  to  remain  on  the  retina 
in  patches,  as  noticed  by  Haller.  It  also  per- 
vades the  structure  of  the  choroid,  at  least  in 
the  adult,  and  even  stains  the  inner  surface  of 
the  sclerotic  and  the  cellular  layer  which  con- 
nects these  two  membranes.  It  is  deposited 
in  larger  quantity  in  the  ciliary  processes  and 
upon  the  back  and  in  the  texture  of  the  iris. 
In  many  animals  it  is  found  forming  a  black 
ring  round  the  margin  of  the  cornea  and  in  the 
edge  of  the  third  eye-lid,  as  well  as  in  the 
pecten  or  marsupium  nigrum  in  birds.  It  is 
even  sometimes  found  scattered,  as  if  acci- 
dentally, as  in  the  texture  of  the  sclerotic  in 
hogs,  and  within  the  sheaths  of  the  optic  nerve 
in  oxen;  it  is  obvious  that  it  does  not  require 
any  special  form  of  organization  for  its  produc- 
tion, but  is  merely  secreted  into  the  cellular 
membrane,  where  necessary,  as  the  colouring 
matter  is  secreted  with  cuticle  on  the  skin. 

It  is  darker  in  the  earlier  periods  of  life,  and 
in  the  infant  is  more  confined  to  the  inner  sur- 
face of  the  choroid  and  to  the  posterior  surface 
of  the  iris,  than  pervading  the  texture  of  either 
of  these  membranes.  In  old  age  it  evidently 
fades,  and  even  appears  as  if  absorbed  in 
patches.  It  is  sometimes  altogether  absent,  as 
in  those  animals  called  albinos,  where  all  the 
parts  usually  coloured  are  unstained.  Its  use 
is  obviously  to  prevent  the  rays  of  light  from 
being  reflected  from  surfaces  where  they  should 
be  absorbed,  a  provision  as  essential  to  the 
perfection  of  the  animal  eye  as  to  the  artificial 
optical  instrument.  It  is  also  applied  to  give 
complete  opacity  to  prevent  the  transmission  of 
light,  and  hence  is  deposited  in  large  quantity 
in  and  on  the  iris,  as  well  as  in  the  ciliary  pro- 
cesses which  correspond  in  situation  to  the 
exposed  part  of  the  sclerotic,  through  which 
the  light  might  otherwise  pass  to  the  bottom  of 
the  eye,  and  disturb  correct  vision.  The  layer 
of  black  pigment  on  the  inner  surface  of  the 
choroid  has  undergone  a  careful  microscopic 
investigation,  especially  by  Mr.  T.  W.  Jones, 
the  results  of  which  are  stated  in  a  short 
account  of  the  anatomy  of  the  eye  prefixed  to 
the  second  edition  of  Mr.  M'Kenzie's  work  on 
Diseases  of  the  Eye:  He  says  that  it  possesses 
organization  and  constitutes  a  real  membrane, 
and  when  examined  with  the  raiscroseope  "  is 


106. 


seen  to  consist  of  very  minute  flat  bodies  of  a 
hexagonal  form,  joined  together  at  their  edges. 
These  bodies,  which  are  about  ^th  of  an  inch 
in  diameter,  consist  of  a  central  transparent 
nucleus,  surrounded  by  an  envelope  of  colour- 
ing matter,  which  is  most  accumulated  at  their 
edges  The  centre,  indeed,  of  each  hexa- 
gonal plate  is  a  transparent  point,  and  appears 
somewhat  elevated,  the  elevations  on  the  inner 
surface  corresponding  to  depressions  to  be 
described  in  the  membrane  of  Jacob.  That 
part  of  the  membrane  of  the  pigment  situated 
on  the  pars  mm  plicata  of  the  ciliary  body 
around  the  ciliary  processes,  and  on  the  poste- 
rior surface  of  the  iris,  is  composed  of  irregu- 
larly rounded  bodies,  analogous  to  the  hexa- 
gonal plates.  In  albinos  the  same  membrane 
exists,  but  contains  no  pigment.  The  bodies 
composing  it  are  but  little  deve- 
loped, being  nothing  but  the  central 
nuclei  separated  from  each  other  by 
large  intervals,  and  not  hexagonal, 
but  circular,  or  even  globular."  The 
annexed  figure  represents  this  mem- 
brane of  the  pigment  as  described. 
Sometimes  the  black  pigment  is  totally  or 
partially  deficient,  not  only  in  inferior  animals, 
but  also  in  man,  constituting  the  variety  deno- 
minated albino,  of  which  the  white  rabbit 
affords  a  good  example.  The  circumstance  lias 
attracted  considerable  attention,  and  has  been 
the  subject  of  particular  observation  by  Mr. 
Hunter,  Blumenbach,  and  many  others.  Dr. 
Sachs  has  given  a  curiously  elaborate  account 
of  himself  and  his  sister,  who  are  botli  albinos. 
The  eye  in  such  cases  appears  of  a  beauti- 
fully brilliant  red,  in  consequence  of  the  blood 
being  seen  circulating  through  the  transparent 
textures  unobscured  by  the  pigment,  but  the 
individual  suffers  from  the  defect  in  conse- 
quence of  the  light  being  transmitted  through 
all  the  exposed  part  of  the  organ ;  proving 
that  the  covering  of  black  pigment  is  deposited 
on  the  back  of  the  iris  and  in  the  ciliary  pro- 
cesses to  obviate  this  injurious  consequence. 
In  human  albinos  the  eyes  have  often  a  tremu- 
lous oscillating  motion,  and  the  individual  is 
unable  to  bear  strong  light. 

The  colour  of  the  black  pigment  does  not  ap- 
pear to  depend  on  the  presence  of  carbon  or 
other  dark  material,  and  the  minute  quantity 
of  oxide  of  iron  contained  in  it  is  obviously 
insufficient  for  the  production  of  so  deep  a  tint. 
It  is  insoluble  in  water,  either  hot  or  cold,  or 
in  dilute  sulphuric  acid  ;  but  strong  nitric  or 
sulphuric  acids  decompose  it,  and  are  decom- 
posed by  it.  Caustic  potash  is  said  to  dissolve 
it,  though  with  difficulty,  but  as  ammonia  is 
evolved  during  the  process,  and  the  nature  of 
the  pigment  necessarily  altered,  it  cannot  be 
considered  a  case  of  simple  solution.  By 
destructive  distillation  it  affords  an  empyreu- 
rcatic  oil,  inflammable  gases,  and  carbonate  of 
ammonia.  It  is,  therefore,  obviously  an  anw 
mal  principle  siii  generis,  its  elements  being 
oxygen,  hydrogen,  carbon,  and  nitrogen.  One 
hundred  parts  in  a  dry  state  leave,  when 
incinerated,  4.46  of  acalx,  consisting  of  chlo- 
ride of  calcium,  carbonate  of  hme,  phosphate 


182 


EYE. 


of  lime,  and  peroxide  of  iron.    For  these  par- 
ticulars I  am  indebted  to  Dr.  Apjohn. 

Of  the  iris. — This  is  the  circular  partition  or 
screen  interposed  between  the  cornea  and  crys- 
talline lens,  filling  up  the  aperture  in  the  ante- 
rior part  of  the  sphere  of  the  choroid,  and  conse- 
quently exactly  fitted  to  the  place  of  union  of  the 
ciliary  ligament  and  choroid  with  the  sclerotic 
round  the  cornea.  It  has  an  aperture  in  the 
centre  called  the  pupil,  through  which  the  central 
portion  of  the  pencil  of  rays  incident  upon  the 
cornea  is  transmitted,  while  the  extreme  rays 
are  intercepted ;  and  appears  to  answer  the 
same  purpose  as  the  diaphragm  or  eye-stop  in 
the  telescope,  but  with  this  advantage,  that  it 
is  enlarged  or  diminished  according  to  the 
quantity  of  light,  the  distance  of  objects,  or 
even  the  will  of  the  individual.  The  iris  is 
frequently  called  uvea,  a  term  also  applied  to 
the  spherical  choroid ;  or  the  anterior  part  is 
called  iris,  and  the  posterior  uvea.  To  avoid 
confusion  the  term  should  be  discarded  alto- 
gether, and  that  of  iris  alone  retained  to 
designate  this  important  part  of  the  organ. 

The  surface  of  the  iris  is  flat  or  plane,  al- 
though it  appears  convex  when  seen  through 
the  cornea,  or  when  in  dissecting  the  eye  it 
falls  on  the  convex  surface  of  the  crystalline 
lens.    It  is  remarkable  that  the  aperture  or 
pupil  is  not  exactly  in  the  centre  of  the  disc, 
but  a  little  towards  the  inside.   The  anterior 
surface  presents  a  very  peculiar  and  remarkable 
appearance,  evidently  not  depending  on  or 
arising  from  vascular  ramifications  or  nervous 
distribution.     This  appearance  is  described 
with  precision  and  accuracy  both  by  Zinn  and 
Haller,  although  unnoticed  or  only  briefly  al- 
luded to  in  many  of  the  slovenly  compilations 
which  have  appeared  since  they  wrote.    It  is, 
however,  described  by  Meckel,  who  saw  what 
he  describes,  and  read  what  he  quotes.  Haller's 
words  are  as  follow : — "  In  anteriori  lamina 
iridis  eminet  natura  flocculenta,  vane  in  flam- 
mulas  quasdam  introrsum  euntes  disposita, 
quibus  aliqua  est  similitudo  rotundorum  ar- 
cuum,  ad  centrum  pupilla;  convexorum.  Qui- 
vis  flocculus  est  serpentinarum  striarum  intror- 
sum convergentium,  et  intermistarum  macu- 
larum   fuscarum   congeries :    conjuncti  vero 
flocculenti  fasciculi  arcuin  quasi  serratum,  emi- 
nentem,  ad  aliquam  a  pupilla  distantiam  effi- 
ciunt,  qui  convexus  eminet,  quasi  antrorsum, 
suprareliquum  planum  pupilleeelatus.  Fabricse 
pulchritudinem  nulla  icon  expressit."  (Ele- 
menta  Physiologic,  torn.  v.  p.  369.)  Zinn's 
description  is  equally  accurate  and  precise. 
In  the  12th  volume  of  the  Medico-Chirurgical 
Transactions  I  have  noticed  this  structure  m 
the  following  words :  "  If  the  iris  be  attentively 
examined  in  the  living  subject,  or  under  water 
after  the  cornea  has  been  removed,  a  number 
of  irregularly  shaped  masses  may  be  seen  pro- 
jecting from  the  middle  space  between  the 
circumference  and  the  pupil.    From  the  con- 
vexities of  these  masses,  a  number  of  elevated 
lines,  equally  irregular  in  size  and  number, 
proceed  toward  the  pupil,  and  attach  them- 
selves at  the  distance  of  about  a  twentieth 
pait  of  ah  inch  from  its  margin,  and  from  this 


point  of  attachment  a  number  of  much  smaller 
stria  converge  to  the  edge  of  the  central  open- 
ing.   It  is  quite  impossible  for  words  to  give 
an  adequate  idea  of  this  appearance.    If  I 
ventured  to  compare  it  with  any  other  with 
which  I  am  acquainted,  I  should  say  that  it 
resembled  strongly  the  carnea  columns  and 
cordce  tendinea  of  the  heart,  both  in  form, 
arrangement,  and  irregularity  of  conformation. 
This  structure  is  more  strongly  marked  in  the 
hazel  than  in  the  blue  iris  ;  and  in  many  cases 
the  fleshy  projections  coalesce,  by  which  they 
appear  less  distinct ;  but  the  loops  or  cords 
which  arise  from  them  always  exist,  and  often 
project  so  much  from  the  plane  of  the  iris  as 
to  admit  of  having  a  small  probe  or  bristle 
passed  beneath  them.    That  this  appearance  of 
the  iris  does  not  depend  on  any  particular 
disposition  of  its  vessels,  i6,  I  think,  obvious, 
from  the  thickness  of  these  cords  or  stric  being 
so  much  greater  than  the  vessels  of  the  iris, 
from  their  being  arranged  in  a  manner  altogether 
different  from  vascular  inosculation,  and  finally, 
because  the  iris  when  successfully  injected  and 
expanded  does  not  present  that  interlacement 
of  branches  surrounding  the  pupil  which  has 
so  often  been  described  from  observation  of  its 
uninjected  state."    The  anterior  surface  of  the 
iris  is  of  a  light  blue  colour  in  persons  of  fair 
skin  and  light  hair,  of  a  blue  grey  in  others, 
sometimes  of  a  mixture  of  tints  called  a  hazel 
iris  ;  and  in  negroes  and  others,  where  the  skin 
is  stained  by  the  usual  colouring  matter,  the 
iris  is  of  a  deep  brown,  and  is  commonly 
described  as  a  black  eye,  being  pervaded  by 
the  black  pigment  throughout  its  texture,  as 
well  as  coated  with  it  on  its  posterior  surface. 
In  animals  altogether  destitute  of  the  usual 
colouring  matter  on  the  surface,  called  albinos, 
the  iris  has  no  other  colour  than  that  of  the 
blood  which  circulates  in  its  vessels.  The 
annexed  engraving  is  a  copy  of  a  most  accu- 
rately executed  representation  of  the  face  of 
the  iris,  shewing  the  cameo1  columna  and 
corda  tendinea  much  magnified. 


Fig.  107. 


The  posterior  surface  of  the  iris  is  as  remark- 
able as  the  anterior,  but  altogether  different  in 
its  nature.  1  have  given  the  following  des- 
cription of  it  in  the  paper  to  which  I  allude  in 


EYE. 


183 


the  Medico-Chirurgical  Transactions.     "  In 
order  to  obtain  a  correct  view  of  the  posterior 
surface  of  the  iris,  a  transverse  vertical  section 
of  the  eye  should  be  made  at  the  distance  of 
about  an  eighth  of  an  inch  behind  the  cornea, 
and  the  lens,  and  portion  of  vitreous  humour 
attached  to  it,  removed  :  the  iris  now  appears 
covered  by  a  thick  layer  of  black  pigment, 
marked  by  a  number  of  converging  lines ; 
these  lines  on  close  inspection  are  found  to  be 
channels  or  hollows,  as  if  resulting  from  a 
puckering  or  folding  of  the  membrane.  The 
pigment  is  secured  from  being  detached,  and 
diffused  in  the  aqueous  humour,  by  a  fine 
transparent  membrane,  which  is  closely  attached 
to  the  margin  of  the  pupil,  from  whence  it  is 
continued  over  the  back  of  the  iris,  and  anterior 
extremities  of  the  ciliary  processes,  to  the  cir- 
cumference of  the  lens,  over  the  front  of  the  • 
capsule  of  which  it  is  also  probably  extended, 
if  it  be,  as  may  be  supposed,  the  membrane  of 
the  aqueous  humour.    This  delicate  membrane 
may  be  turned  down  by  the  point  of  a  needle  ; 
as  it  is  connected  to  the  iris  by  loose  cellular 
structure  only,  in  the  interstices  of  which  the 
black  pigment  is  deposited.  It  is  at  first  black, 
but  by  gentle  agitation  in  water  the  colouring 
matter  is  removed,  and  the  membrane  remains 
transparent.    When  the  membrane  and  pig- 
ment have  been  removed,  the  back  of  the  iris 
appears  free  from  colour,  and  marked  by  a 
number  of  delicate  elevated  folds,  converging 
from  the  ciliary  processes  to  within  a  short 
distance  of  the  pupil ;  they  are  permanent  and 
essential,  and  seem  of  the  same  nature  as  the 
ciliary  processes.    The  pupil  is  immediately 
surrounded  by  a  well-defined  distinct  circle, 
about  the  twentieth  part  of  an  inch  in  diameter, 
of  a  denser  structure  than  the  rest  of  the  iris  : 
this  is  what  has  been  long  described  as  the 
orbicular  muscle,  or  constrictor  of  the  pupil. 
If  the  iris  be  treated,  as  I  before  mentioned,  by 
maceration  and  extension,  this  appearance  still 
preserves  its  integrity,  and  retains  its  original 
character."     Haller  and  Zinn  describe  these 
converging  radiating  folds,  but  the  former  de- 
nies the  existence  of  the  circular  arrangement 
round  the  margin  of  the  pupil,  of  the  presence 
of  which  I  do  not  entertain  the  slightest  doubt, 
but  which  is  sometimes  so  slightly  marked, 
that  I  am  not  surprized  to  find  its  existence 
doubted  if  the  part  has  not  been  examined  in 
a  variety  of  examples.  This  circle,  or  orbicular 
muscle,  is  sometimes  equally  visible  on  the 
anterior  surface,  but  is  generally  obscured  by 
the  converging  cords  above  described.  The 
folds  or  elevations  on  the  back  of  the  iris,  con- 
verging toward  the  pupil,  have  been  considered 
the  muscular  agents  for  dilating  the  pupil,  but 
if  examined  in  the  eyes  of  the  larger  quadru- 
peds, it  is  obvious  that  they  are  destined  to  give 
this  part  of  the  organ  the  requisite  degree  of 
opacity,  and  to  afford  an  appropriate  place  for 
the  deposit  of  the  black  pigment,  in  this  res- 
pect closely  resembling  the  ciliary  processes, 
and  the  pecten  in  the  eye  of  birds,  so  much 
so,  that  I  think  they  might  be  appropriately 
called  the  ciliary  processes  of  the  iris. 

The  iris  is  most  plentifully  supplied  with 


bloodvessels  and  nerves.  The  two  long  ciliary 
arteries  which  penetrate  the  sclerotic  posteri- 
orly advance  horizontally,  about  the  middle 
of  the  eyeball,  between  that  membrane  and  the 
choriod,  to  the  iris,  where  each  divides  into  two 
branches,  which  proceed  round  the  circumfer- 
ence and  inosculate  with  each  other,  thus  form- 
ing an  arterial  circle,  from  which  numberless 
branches  converge  to  the  pupil.  Much  impor- 
tance has  been  attached  by  anatomists  to  the 
manner  in  which  these  radiating  vessels  are 
disposed,  in  consequence  of  the  representation 
of  Ruysch,  who  exhibited  them  as  forming  a 
series  of  inosculations  at  a  short  distance  from 
the  pupil,  since  called  the  lesser  circle  of  the 
iris.  I  do  not  deny  that  the  vessels  of  the  iris 
inosculate  as  in  other  parts  of  the  body,  but  I 
do  not  believe  that  they  present  this  very  re- 
markable appearance,  and  I  suspect  that 
Ruysch  exaggerated  what  he  had  seen,  or  de- 
scribed from  an  iris  in  which  the  injection  had 
been  extravasated  and  entangled  in  the  tendi- 
nous cords,  which  I  have  described  as  extend- 
ing from  the  fleshy  bodies  to  the  margin  of  the 
pupil.  The  question  is  fortunately  of  no 
importance.  It  is  sufficient  to  know  that  the 
organ  is  amply  supplied  with  arterial  blood. 

The  iris  is  plentifully  furnished  with 
nerves  :  they  are  derived  from  the  third  and 
fifth  pairs,  with  communications  from  the  sym- 
pathetic, and  consequently  having  connexions 
with  the  sixjth.  They  penetrate  the  sclerotic 
posteriorly,  and  advance  towards  the  iris  be- 
tween the  sclerotic  and  choroid,  about  fifteen 
or  twenty  in  number :  arrived  at  the  ciliary 
ligament,  they  divide  at  acute  angles,  and  may 
be  traced  through  this  structure  until  they  are 
finally  lost  in  the  iris,  as  seen  in  the  annexed 
figure. 


Fig.  108. 


From  the  foregoing  description,  it  appears 
that  the  iris  is  eminently  distinguished  for  the 
perfection  of  its  organization  ;  and  endowed  as 
it  is  with  the  power  of  enlarging  or  diminishing 
the  aperture  in  its  centre,  there  can  be  little 
doubt  that  it  is  a  beautiful  application  of  mus- 
cular structure  and  function  to  the  perfection 
of  this  most  elaborately  constructed  organ. 
The  authority  of  Haller  operates  to  the  pre- 
sent day  to  throw  a  doubt  upon  the  muscula- 
rity of  the  iris ;  but  Haller,  strange  as  it  may 
appear,  was  not  correctly  informed  in  many 
particulars  respecting  this  structure.  He  de- 
nies the  existence  of  the  orbicular  muscle ;  he 
doubts  the  irritability  of  the  organ,  and  he  even 


184 


EYE. 


considers  it  destitute  of  sensibility,  and  as- 
sumes that  the  pupil  is  dilated  after  death. 
Any  anatomist  may,  however,  demonstrate  the 
orbicular  muscle;  any  surgeon  breaking  up  a 
cataract,  may  elicit  the  irritability,  and  see  the 
pupil  contract,  as  the  fragments  of  the  lens  or 
the  side  of  the  needle  touch  its  margin.  The 
pain  produced  by  pinching  or  cutting  the  iris 
in  operations  for  cataract  and  artificial  pupil  is 
no  longer  matter  of  doubt,  and  the  assumption 
that  the  pupil  dilates  when  death  takes  place 
is  disproved  by  daily  observation.  The  pupd 
contracts  to  exclude  light  when  too  abundant, 
and  dilates  to  admit  it  when  deficient  in  quan- 
tity ;  the  heart  contracts  to  expel  the  blood, 
and  dilates  to  receive  it;  the  diaphragm  con- 
tracts to  fill  the  lungs,  and  relaxes  to  assist  in 
emptying  them.  I  can  see  no  material  differ- 
ence between  the  phenomena  exhibited  by  the 
actions  of  the  iris,  and  those  displayed  by  the 
muscular  system  generally.  I  believe  that  when 
the  pupil  contracts  to  intercept  light,  that  con- 
traction is  accomplished  by  the  orbicular  mus- 
cle, which  operates  as  any  other  sphincter ; 
and  that  when  the  pupil  is  dilated  to  admit 
light,  the  dilatation  is  accomplished  by  the  con- 
traction of  the  structure,  which  I  have  said  re- 
sembles the  carnea  columnm  and  corda  tendinea 
in  the  heart. 

During  foetal  life  the  aperture  in  the  centre  is 
closed  by  a  membrane,  hence  technically  called 
membrana  pupi/laris.  The  discovery  of  this 
membrane  was  first  announced  by  VVachendorf, 
but  was  subsequently  claimed  by  Albinus,  and 
still  later  by  Dr.  Hunter  for  a  person  of  the 
name  of  Sandys.  It  is  usually  described  as 
existing  from  the  earliest  period  of  fatal  life  to 
the  seventh  month,  when  it  disappears.  In  the 
paper  communicated  by  me  to  the  Medico- 
Chirurgical  Society,  I  have  endeavoured  to 
shew  that  this  description  is  not  correct,  but  that 
this  membrane  continues  to  the  ninth  month. 
The  account  there  given  is  as  follows  :  "  If  the 
eye  be  examined  about  the  fifth  month,  the 
membrana  papillaris  is  found  in  great  perfec- 
tion, extended  across  a  very  large  pupil ;  the 
vessels  presenting  that  singular  looped  arrange- 
ment, (with  a  small  irregular  transparent  por- 
tion in  the  centre,)  well  depicted  by  Wrisberg, 
Blumenbach,  Albinus,  Sommerring,  Cloquet, 
and  others.  About  the  sixth  month  it  is  equally 
perfect;  the  pupil  is  however  smaller,  the  iris 
being  more  developed.  Subsequently  to  this 
date  the  vessels  begin  to  diminish  in  size  and 
number,  and  a  larger  transparent  portion  occu- 
pies the  centre.  At  the  approach  of  the  eighth 
month,  a  few  vessels  cross  the  pupil,  or  ramify 
through  the  membrane  at  a  short  distance  from 
the  margin,  without  at  all  presenting  the  looped 
appearance  of  the  previous  period,  but  ad- 
muting  a  free  communication  between  the  ves- 
sels of  the  opposite  side  of  the  iris.  The  pupil 
is  now  still  more  diminished  in  size,  and  the 
iris  has  assumed  its  characteristic  coloured  ap- 
pearance; notwithstanding  the  absence  of  ves- 
sels, the  membrane  still  preserves  its  integrity, 
though  perfectly  transparent.  The  period  now 
approaches  when  it  is  to  disappear;  this  occur- 
rence takes  place,  according  to  my  observations, 


a  short  time  previous  or  subsequent  to  birth. 
In  every  instance  where  I  have  made  the  exa- 
mination, I  have  found  the  membrana  papillaris 
existing  in  a  greater  or  less  degree  of  perfection 
in  the  new-born   infant;    frequently  perfect 
without  the  smallest  breach,  sometimes  pre- 
senting ragged  apertures  in  several  places,  and, 
in  other  instances,  nothing  existing  but  a  rem- 
nant hanging  across  the  pupil  like  a  cobweb. 
I  have  even  succeeded  in  injecting  a  single  ves- 
sel in  the  membrana  papillaris  of  the  ninth 
month.    Where  I  have  examined  it  in  subjects 
who  have  lived  for  a  week  or  fortnight  after 
birth,  as  proved  by  the  umbilicus  being  healed, 
I  have  uniformly  found  a  few  shreds  still  re- 
maining.    It  is  obvious  from  the  preceding 
observations,  that  the  membrane  does  not  dis- 
appear by  a  rent  taking  place  in  the  centre, 
and  retraction  of  the  vessels  to  the  iris,  as  sup- 
posed by  Blumenbach,  but  that  it  at  first  loses 
its  vascularity,  then  becomes  exceedingly  thin 
and  delicate,  and  is  finally  absorbed.    The  de- 
monstration of  what  I  have  advanced  respect- 
ing this  delicate  part  is  attended  with  much 
difficulty,  and  requires  great  patience.  The 
display  of  the  membrana  papillaris  of  the  seventh 
month  is  comparatively  easy  ;  but  at  the  ninth 
month,  or  subsequently,  it  can  only  be  accom- 
plished by  particular  management.    The  eye, 
together  with  the  appendages,  should  be  care- 
fully removed  from  the  head ;  it  should  then 
be  freed  from  all  extraneous  parts  by  the  scis- 
sors, under  water,  and  a  careful  section  made 
at  a  short  distance  behind  the  cornea;  taking 
care  to  include  the  vitreous  humour  in  the  divi- 
sion, in  order  that  the  lens  may  remain  in  its 
proper  situation.    The  portion  to  be  examined 
should  now  be  removed  into  a  shallow  vessel  of 
water,  to  the  bottom  of  which  a  piece  of  wax 
has  been  secured.    The  operator  should  be 
provided  with  fine  dissecting  forceps  and  nee- 
dles in  light  handles;  with  one  needle  he 
should  pin  the  sclerotic  down  to  the  wax,  and 
with  the  other  raise  the  lens,  and  portion  of 
vitreous  humour  attached  to  it,  from  the  ciliary 
processes,  and  separate  the  ciliary  ligament 
from  the  sclerotic.    He  may  now  expect  to  dis- 
cover the  membrana  pupillaris,  but  its  perfect 
transparency  renders  it  completely  invisible ; 
he  may,  however,  ascertain  the  existence,  by 
taking  a  minute  particle  of  the  retina  and 
dropping  it  into  the  centre  of  the  pupil,  where 
it  remains  suspended  if  this  membrane  exist. 
The  preparation  should  now  be  taken  up  in 
a  watch-glass,  and  placed  in  a  weak  mix- 
ture of  spirit  and  water,  and  a  little  pow- 
dered alum  raised  on  the  point  of  a  needle 
dropped  upon  it.    After  a  day  or  two  it  may 
be  examined;  and  if  the  membrane  be  pre- 
sent,  it  has  become  sufficiently  opaque  to 
be  visible,  and  may  now  be  suspended  in  a 
bottle  of  very  dilute  spirit."    In  the  annexed 
engravings,  A  represents  the  membrana  pu- 
pillaris of  about  the  fifth  month,  present- 
ing the  peculiar  looped  arrangement  of  the 
vessels.    B  represents  the  membrane  about  the 
eighth  month,  not  presenting  the  looped  ar- 
rangement.   C  represents  the  membrane  with  a 
red  vessel  in  its  structure  at  the  ninth  month.  D 


EYE. 


185 


shews  a  few  shreds  of  the  membrane  remaining 
a  week  or  more  after  birth. 


Fig.  109. 


The  pupil  is  closed  by  this  membrane  during 
foetal  life  in  order  to  preserve  its  dimensions, 
and  secure  a  correct  growth  of  the  iris  while  the 
organ  is  in  darkness.  If  the  membrane  disap- 
peared about  the  seventh  month,  the  pupil 
should  become  dilated  and  remain  so  during 
the  two  succeeding  months,  unless  the  muscu- 
lar power  be  undeveloped,  which  is  not  proba- 
ble, as  it  may  be  seen  to  operate  shortly  after 
birth. 

Of  the  retina.  —  This  is  the  third  spheri- 
cally disposed  membrane  entering  into  the 
structure  of  the  eye,  and  may  be  considered 
the  most  essential  of  all,  being  that  which 
is  endowed  with  the  peculiar  description  of 
sensibility  which  renders  the  individual  con- 
scious of  the  presence  of  light.  It  is  as 
exactly  fitted  to  the  inside  of  the  choroid  as 
that  membrane  is  to  the  sclerotic,  but  does 
not  extend  to  the  anterior  margin  of  the  choroid 
as  that  structure  extends  to  the  anterior  margin 
of  the  sclerotic.  The  retina  is  destined  to  be 
penetrated  by  the  rays  of  light,  which,  reflected 
from  surrounding  objects,  are  collected  to  form 
images  on  the  bottom  of  the  eye,  consequently 
its  extension  as  far  forward  as  the  choroid  or 
sclerotic  is  unnecessary,  and  nature  makes  no- 
thing superfluous.  It  is  discontinued  at  the 
posterior  extremities  of  the  ciliary  processes  of 
the  choroid,  at  the  distance  of  about  an  eighth 
of  an  inch  from  the  anterior  margin  of  that 
membrane. 

The  retina  is  evidently  the  optic  nerve  ex- 
panded in  the  bottom  of  the  eye  in  the  form  of 
a  segment  of  a  sphere.  That  nerve  differs,  in 
some  respects,  in  construction  from  the  other 
nerves  of  the  body.  In  its  course  from  the 
hole  in  the  bone  through  which  it  enters  the 
orbit  until  it  enters  the  eye,  it  is  of  a  cylindrical 
form,  and  proceeds  in  a  waving  line  to  its  desti- 
nation. The  medullary  fibres  are  involved  in  a 
tough  strong  material,  not  separable  into  cords 
or  bundles  as  in  other  nerves,  but  constituting 
a  cylinder  of  collected  tubes,  from  the  divided 
extremity  of  which  the  medullary  matter  may  be 
squeezed  in  as  soft  and  pulpy  a  form  as  it  exists 


in  the  brain.  It  is  not  easy  to  determine  by 
anatomical  investigation,  whether  the  medullary 
material  is  disposed  in  tubes  or  in  a  cellular 
structure,  but  as  that  material  is  universally 
disposed  in  a  fibrous  form,  both  in  brain  and 
nerve,  it  is  more  than  probable  that  it  is  so  ar- 
ranged here.  These  cerebral  fibres  involved 
thus  in  a  cylindrical  bundle  of  tubes,  techni- 
cally called  neurilema  by  modern  anatomists, 
is  covered  externally  by  a  fine  transparent 
membrane,  adhering  to  it  so  closely  that  it  re- 
quires some  care  to  separate  it;  and  this  is 
again  covered  by  a  tube  of  strong  fibrous  mem- 
brane, the  sheath  of  the  optic  nerve  continued 
from  the  dura  mater  to  the  sclerotic,  to  which 
membrane  it  adheres  so  firmly,  that  it  cannot 
be  separated  except  by  the  knife.  Formerly 
the  sclerotic  was  considered  to  be  a  continuation 
of  the  dura  mater,  and  much  importance,  in  a 
pathological  point  of  view,  was  attached  to  the 
circumstance,  but  although  both  structures  are 
of  the  fibrous  class,  the  sclerotic  is  very  different 
in  texture,  and  the  adhesion  between  them  is 
not  more  remarkable  than  any  other  of  the 
numerous  adhesions  which  occur  between  fi- 
brous membranes. 

Where  the  optic  nerve  enters  the  eye,  it  is 
contracted  in  diameter,  as  if  a  string  had  been 
tied  round  it,  and  then  passes  through  a  hole 
in  the  sclerotic,  to  which  it  adheres.  When 
seen  from  the  inside,  after  removing  the  retina 
and  choroid,  it  appears  in  the  form  of  a  circu- 
lar spot,  perforated  with  small  holes,  from 
which  the  medullary  material  may  be  expressed. 
This  is  the  lamina  cribrosa  of  Albinus,  consi- 
dered to  be  a  part  of  the  sclerotic,  but  which  is 
really  nothing  more  than  the  terminating  ex- 
tremity of  the  nerve. 

The  optic  nerve  does  not  enter  the  eye  in  the 
centre  of  the  globe,  but  ahout  an  eighth  of  an 
inch  to  the  side  of  it,  assuming  the  centre  to 
correspond  to  the  extremity  of  a  line  passing 
from  the  middle  of  the  cornea,  through  the 
centre  of  the  eyeball  to  its  back.  The  nerve 
is  generally  described  and  represented  as  pro- 
jecting in  the  form  of  a  round  prominence,  as 
it  enters  the  eye  ;  but  this  is  not,  I  believe,  the 
state  of  the  part  dining  life,  but  is  produced 
by  the  contraction  of  the  neurilema  pressing 
out  the  medullary  matter  in  this  form.  As 
the  nerve  enters  the  eye,  it  immediately  expands 
into  and  constitutes  the  retina,  the  medullary 
fibres  separating  and  spreading  out  on  the  sphe- 
rical vitreous  humour.  The  expansion  of  the 
nerve  in  separate  fibres  cannot  be  distinctly 
seen  in  the  human  eye,  but  may  be  recognized 
with  some  care  in  the  eye  of  the  ox,  and  with- 
out difficulty  in  that  of  the  hare  and  rabbit, 
where  it  divides  into  two  bundles,  as  has  been 
well  described  by  Zinn  in  the  Gottingen  Com- 
mentaries. 

The  retina  does  not  consist  of  medullary  or 
cerebral  fibrous  matter  alone.  As  the  brain 
has  its  pia  mater  and  arachnoid  membrane, 
and  the  nerve  its  neurilema,  this  nervous  struc- 
ture has  its  appropriate  provision  for  its  sup- 
port and  the  distribution  of  its  vessels.  This 
is  the  vascular  layer,  first  accurately  described 
by  Albinus.    It  is  a  delicate  transparent  mem- 


186 


EYE. 


brane,  of  such  strength,  that  when  detached,  it 
may  be  moved  about  in  water,  and  freely  ex- 
amined without  breaking.  It  adheres  so  firmly 
to  the  hyaloid  membrane  of  the  vitreous  hu- 
mour in  the  fresh  eye,  that  it  cannot  be  sepa- 
rated entire,  and  the  medullary  fibres  adhere 
so  closely  to  its  external  surface,  that  they  can- 
not be  detached  at  all  in  the  form  of  a  distinct 
membrane.  To  demonstrate  the  vascular  layer, 
the  sclerotic  should  be  carefully  removed,  leav- 
ing a  portion  of  the  optic  nerve  freed  from  its 
sheath  ;  the  choroid  should  then  also  be  re- 
moved under  water,  by  tearing  it  asunder  with 
a  pair  of  forceps  in  each  hand.  The  vitreous 
humour,  covered  by  the  retina  only,  should 
then  be  allowed  to  remain  about  two  days  in 
the  water,  at  the  end  of  which  time  the  me- 
dullary layer  softens  and  separates  into  flakes, 
which  may  be  scraped  from  the  vascular  layer 
beneath  by  passing  the  edge  of  a  knife  gently 
over  it,  after  which  the  vascular  layer  may  be 
detached  by  careful  management,  and  sus- 
pended in  a  bottle  from  the  optic  nerve. 

The  retina  is  supplied  with  blood  from  the 
ophthalmic  artery,  a  small  branch  of  which 
penetrates  the  optic  nerve  at  a  short  distance 
from  the  back  of  the  eye,  and  proceeds  through 
its  centre  until  it  arrives  at  the  retina.  The 
hole  in  the  centre  of  the  nerve,  through  which 
it  passes,  was  formerly  called  the  porus  opticus. 
Arrived  at  the  retina,  the  vessel,  under  the 
name  of  the  central  artery  of  the  retina,  divides 
into  two  branches,  which  surround  the  foramen 
of  Sdmmerring,  and  sending  ramifications  in 
every  direction,  terminate  by  encircling  the  an- 
terior margin.  Besides  the  branches  which 
carry  red  blood,  the  central  artery  probably 
furnishes  a  transparent  branch  to  the  centre  of 
the  vitreous  humour,  as  such  a  branch  running 
on  to  the  back  of  the  crystalline  lens,  may  be 
injected  in  the  eye  of  the  foetus,  and  a  transpa- 
rent production  from  the  central  artery  into  the 
vitreous  humour  may  be  observed  in  the  eyes 
of  oxen  and  other  large  animals.  The  arteries 
of  the  retina  supply  the  vitreous  humour  with 
blood,  as  no  other  source  exists,  except  from 
the  ciliary  processes  of  the  choroid,  which, 
being  buried  in  the  hyaloid  membrane,  most 
probably  furnish  vessels  to  the  anterior  part, 
and  in  dissecting  the  vascular  layer  above  de- 
scribed, in  which  the  vessels  ramify,  it  is  found 
to  adhere  to  the  hyaloid  membrane  by  points 
along  the  course  of  the  vessels,  which  points,  it 
is  reasonable  to  believe,  are  small  branches. 

As  the  medullary  or  cerebral  fibres  of  the 
retina  are  sustained  on  the  inside  by  the  vascu- 
lar layer  above  described,  they  are  also  protected 
on  the  outside  by  another  membrane,  which 
separates  them  from  the  inner  surface  of  the 
choroid.  This  is  the  membrane  which  I  des- 
cribed in  a  communication  in  the  Philosophical 
Transactions  in  1819,  and  as  I  cannot  give  a 
more  intelligible  account  of  it  than  that  there 
contained,  I  venture  to  introduce  it  here. 

"  Anatomists  describe  the  retina  as  consisting 
of  two  portions,  the  medullary  expansion  of 
the  nerve,  and  a  membranous  or  vascular  layer. 
The  former  externally,  next  to  the  choroid  coat, 
and  the  latter  internally,  next  to  the  •  vitreous 


humour.  All,  however,  except  Albinus  and 
some  of  his  disciples,  agree,  that  the  nervous 
layer  cannot  be  separated  so  as  to  present  the 
appearance  of  a  distinct  membrane,  though  it 
may  be  scraped  off.  leaving  the  vascular  layer 
perfect.  That  the  medullary  expansion  of  the 
optic  nerve  is  supported  by  a  vascular  layer, 
does  not,  I  think,  admit  of  doubt ;  but  it  does 
not  appear  that  Albinus  was  right  in  supposing 
that  the  nervous  layer  can  be  separated  in  form 
of  a  distinct  membrane,  though  shreds  of  a 
considerable  size  may  be  detached,  especially  if 
hardened  by  acid  or  spirit. 

"  Exclusive  of  these  two  layers,  I  find  that 
the  retina  is  covered  on  its  external  surface  by 
a  delicate  transparent  membrane,  united  to  it 
by  cellular  substance  and  vessels.  This  struc- 
ture, not  hitherto  noticed  by  anatomists,  I  first 
observed  in  the  spring  of  the  last  year,  and 
have  since  so  frequently  demonstrated,  as  to 
leave  no  doubt  on  my  mind  of  its  existence  as 
a  distinct  and  perfect  membrane,  apparently  of 
the  same  nature  as  that  which  lines  serous  cavi- 
ties. I  cannot  describe  it  better,  than  by  detailing 
the  method  to  be  adopted  for  examining  and  dis- 
playing it.  Having  procured  a  human  eye, 
within  forty-eight  hours  after  death,  a  thread 
should  be  passed  through  the  layers  of  the  cor- 
nea, by  which  the  eye  may  be  secured  under 
water,  by  attaching  it  to  a  piece  of  wax,  previ- 
ously fastened  to  the  bottom  of  the  vessel,  the 
posterior  half  of  the  sclerotic  having  been  first 
removed.  With  a  pair  of  dissecting  forceps 
in  each  hand,  the  choroid  coat  should  be  gently 
torn  open  and  turned  down.  If  the  exposed 
surface  be  now  carefully  examined,  an  ex- 
perienced eye  may  perceive,  that  this  is  not 
the  appearance  usually  presented  by  the  retina  ; 
instead  of  the  blue-white  reticulated  surface  of 
that  membrane,  a  uniform  villous  structure, 
more  or  less  tinged  by  the  black  pigment,  pre- 
sents itself.  If  the  extremity  of  the  ivory 
handle  of  a  dissecting  knife  be  pushed  against 
this  surface,  a  breach  is  made  in  it,  and  a  mem- 
brane of  great  delicacy  may  be  separated  and 
turned  down  in  folds  over  the  choroid  coat, 
presenting  the  most  beautiful  specimen  of  a 
delicate  tissue  which  the  human  body  affords. 
If  a  small  opening  be  made  in  the  membrane, 
and  the  blunt  end  of  a  probe  introduced  be- 
neath, it  may  be  separated  throughout,  without 
being  turned  down,  remaining  loose  over  the 
retina  ;  in  which  state  if  a  small  particle  of  paper 
or  globule  of  air  be  introduced  under  it,  it  is 
raised  so  as  to  be  seen  against  the  light,  and  is 
thus  displayed  to  great  advantage ;  or  it  is 
sometimes  so  strong  as  to  support  small  glo- 
bules of  quicksilver  dropped  between  it  and 
the  retina,  which  renders  its  membranous  na- 
ture still  more  evident.  If  a  few  drops  of  acid 
be  added  to  the  water  after  the  membrane  has 
been  separated,  it  becomes  opaque  and  much 
firmer,  and  may  thus  be  preserved  for  several 
days,  even  without  being  immersed  in  spirit. 

"  That  it  is  not  the  nervous  layer  which  I  de- 
tach, is  proved  by  the  most  superficial  exa- 
mination; first,  because  it  is  impossible  to 
separate  that  part  of  the  retina,  so  as  to  present 
the  appearance  I  mention  ;  and,  secondly,  be- 


EYE. 


187 


cause  I  leave  the  retina  uninjured,  and  present- 
ing the  appearance  described  by  anatomists, 
especially  the  yellow  spot  of  Soemmering, 
which  is  never  seen  to  advantage  until  this 
membrane  be  removed  :  and  hence  it  is  that 
conformation,  as  well  as  the  fibrous  structure 
of  the  retina  in  some  animals,  become  better 
marked  from  remaining  some  time  in  water, 
by  which  the  membrane  I  speak  of  is  de- 
tached. 

"  The  extent  and  connections  of  this  mem- 
brane are  sufficiently  explained  by  saying,  that 
it  covers  the  retina  from  the  optic  nerve  to  the 
ciliary  processes.  To  enter  into  farther  inves- 
tigation on  this  subject  would  lead  to  a  dis- 
cussion respecting  the  structure  of  the  optic 
nerve,  and  the  termination  of  the  retina  an- 
teriorly, to  which  it  is  my  intention  to  return  at 
a  future  period. 

"The  appearance  of  this  part  I  find  to  vary 
in  the  different  classes  of  animals  and  in  man, 
according  to  age  and  other  circumstances.  In 
the  foetus  of  nine  months  it  is  exceedingly  de- 
licate, and  with  difficulty  displayed.    In  youth 
it  is  transparent,  and  scarcely  tinged  by  the 
black  pigment.     In  the  adult  it  is  firmer,  and 
more  deeply  stained  by  the  pigment,  which 
sometimes  adheres  to  it  so  closely  as  to  colour 
it  almost  as  deeply  as  the  choroid  coat  itself; 
and  to  those  who  have  seen  it  in  this  state,  it 
must  appear  extraordinary  that  it  should  not  have 
been  before  observed-    In  one  subject,  aged 
fifty,  it  possessed  so  great  a  degree  of  strength 
as  to  allow  me  to  pass  a  probe  under  it,  and 
thus  convey  the  vitreous  humour  covered  by  it 
and  the  retina  from  one  side  of  the  basm  to  the 
other  ;   and  in  a  younger  subject  I  have  seen  it 
partially  separated  from  the  retina  by  an  effused 
fluid.    In  the  sheep,  ox,  horse,  or  any  other 
individual  of  the  class  mammalia  which  I  have 
had  an  opportunity  of  examining,  it  presents 
the  same  character  as  in  man  ;  but  is  not  so 
much  tinged  by  the  black  pigment,  adheres 
more  firmly  to  the  retina,  is  more  uniform  in  its 
structure,  and  presents  a  more  elegant  appear- 
ance when  turned  down  over  the  black  choroid 
coat.  In  the  bird  it  presents  a  rich  yellow  brown 
tint,  and  when  raised,  the  blue  retina  presents  it- 
self beneath  ;  in  animals  of  this  class,  however,  it 
is  difficult  to  separate  it  to  any  extent,  though  I 
can  detach  it  in  small  portions.  In  fishes,  the  struc- 
ture of  this  membrane  is  peculiar  and  curious. 
It  has  been  already  described  as  the  medullary 
layer  of  the  retina  by  Haller  and  L'uvier,  but 
I  think  incorrectly,  as  it  does  not  present  any 
of  the  characters  of  nervous  structure,  and  the 
retina  is  found  perfect  beneath  it.    If  the  scle- 
rotic coat  be  removed  behind,  with  the  choroid 
coat  and  gland  so  called,  the  black  pigment  is 
found  resting  upon,  and  attached  to,  a  soft 
friable  thick  fleecy  structure,  which  can  only 
be  detached  in  small  portions,  as  it  breaks 
when  turned  down  in  large  quantity.  Or  if  the 
cornea  and  iris  be  removed  anteriorly,  and  the 
vitreous  humour  and  lens  withdrawn,  the  retina 
muy  be  pulled  from  the  membrane,  which  re- 
mains attached  to  the  choroid  coat,  its  inner 
surlace  not  tinged  by  the  black,  pigment,  but 


presenting  a  clear  white,  not  unaptly  compared 
by  llaller  to  snow. 

"  Besides  being  connected  to  the  retina,  I  find 
that  the  membrane  is  also  attached  to  the  cho- 
roid coat,  apparently  by  fine  cellular  substance 
and  vessels ;  but  its  connection  with  the  retina 
being  stronger,  it  generally  remains  attached 
to  that  membrane,  though  small  portions  are 
sometimes  pulled  off  with  the  choroid  coat. 
From  this  fact  I  think  it  follows,  that  the 
accounts  hitherto  given  of  the  anatomy  of  these 
parts  are  incorrect.    The  best  anatomists  de- 
scribe the  external  surface  of  the  retina  as 
being  merely  in  contact  with  the  choroid  coat, 
as  the  internal  with  the  vitreous  humour,  but 
both  totally  unconnected   by  cellular  mem- 
brane, or  vessels,   and  even  having  a  fluid 
secreted  between  them  :  some  indeed  speak 
loosely  and  generally  of  vessels  passing  from 
the  choroid  to  the  retina,  but  obviously  not 
from  actual  observation,  as  I  believe  no  one 
has  ever  seen  vessels  passing  from  the  one 
membrane  to  the  other.    My  observations  lead 
me  to  conclude,  that  wherever  the  different 
parts  of  the  eye  are  in  contact,  they  are  con- 
nected to  each  other  by  cellular  substance, 
and,  consequently,  by  vessels ;  for  I  consider 
the  failure  of  injections  no  proof  of  the  want 
of  vascularity  in  transparent  and  delicate  parts, 
though  some  anatomists  lay  it  down  as  a  cri- 
terion.   Undoubtedly  the  connection  between 
these  parts  is  exceedingly  delicate,  and,  hence, 
is  destroyed  by  the  common  method  of  ex- 
amining this  organ ;  but  I  think  it  is  proved 
in  the  following  way.    I  have  before  me  the 
eye  of  a  sheep  killed  this  day,  the  cornea 
secured  to  a  piece  of  wax  fastened  under  water, 
and  the  posterior  half  of  the  sclerotic  coat 
carefully  removed.    I  thrust  the  point  of  the 
blade  of  a  pair  of  sharp  scissors  through  the 
choroid  coat  into  the  vitreous  humour,  to  the 
depth  of  about  an  eighth  of  an  inch,  and 
divide  all,  so  as  to  insulate  a  square  portion 
of  each  membrane,  leaving  the  edges  free,  and 
consequently  no  connection  except  by  surface; 
yet  the  choroid  does  not  recede  from  the  mem- 
brane I  describe,  the  membrane  from  the 
retina,  nor  the  retina  from  the  vitreous  humour. 
I  take  the  end  of  the  portion  of  choroid  in  the 
forceps,  turn  it  half  down,  and  pass  a  pin 
through  the  edge,  the  weight  of  which  is  in- 
sufficient to  pull  it  from  its  connection.    I  se- 
parate the  membrane  in  like  manner,  but  the 
retina  I  can  scarcely  detach  from  the  vitreous 
humour,  so  strong  is  the  connection.  The 
same  fact  may  be  ascertained  by  making  a 
transverse  vertical  section  of  the  eye,  removing 
the  vitreous  humour  from  the  posterior  seg- 
ment, and  taking  the  retina  in  the  forceps, 
pulling  it  gently  from  the  choroid,  when  it  will 
appear  beyond  a  doubt  that  there  is  a  connec- 
tion between  them. 

"  Let  us  contrast  this  account  of  the  matter 
with  the  common  one.  The  retina,  a  raein- 
biane  of  such  delicacy,  is  described  as  being 
extended  between  the  vitreous  humour  and 
choroid,  from  the  optic  nerve  to  the  ciliary 
processes,  being  mere'y  laid  between  them, 


188 


EYE. 


without  any  connection,  and  the  medullary 
fibres  in  contact  with  a  coloured  mucus  re- 
tained in  its  situation  by  its  consistence  alone. 
This  account  is  totally  at  variance  with  the 
general  laws  of  the  animal  economy ;  in  no 
instance  have  we  parts,  so  dissimilar  in  nature, 
in  actual  contact:  wherever  contact  without 
connection  exists,  each  surface  is  covered  by  a 
membrane,  from  which  a  fluid  is  secreted; 
and  wherever  parts  are  united,  it  is  by  the 
medium  of  cellular  membrane,  of  which  se- 
rous membrane  may  be  considered  as  a  mo- 
dification.   If  the  retina  be  merely  in  contact 
with  the  vitreous  humour  and  choroid,  we 
argue  from  analogy,  that  a  cavity  lined  by 
serous  membrane  exists  both  on  its  internal 
and  external  surface :  but  this  is  not  the  fact. 
In  the  eye  a  distinction  of  parts  was  necessary, 
but  to  accomplish  this  a  serous  membrane  was 
not  required  ;  it  is  only  demanded  where  great 
precision  in  the  motion  of  parts  was  indis- 
pensable, as  in  the  head,  thorax,  and  abdo- 
men ;  a  single  membrane,  with  the  interpo- 
sition of  cellular  substance,  answers  the  pur- 
pose here.    By  this  explanation  we  surmount 
another  difficulty,  the  unphilosophical  idea 
of  the  colouring  matter  being  laid  on  the 
choroid,  and  retained  in  its  situation  by  its 
viscidity,  is  discarded;  as  it  follows,  if  this 
account  be  correct,  that  it  is  secreted  into  the 
interstices  of  fine  cellular   membrane  here, 
as  it  is  upon  the  ciliary  processes,  back  of  the 
iris,  and  pecten,  under  the  conjunctiva,  round 
the  cornea,  and  in  the  edge  of  the  membrana 
nictitans  and  sheath  of  the  optic  nerve  in  many 
animals.     Dissections    are  recorded  where 
fluids  have  been  found  collected  between  the 
choroid  and  retina,  by  which  the  structure  of 
the  latter  membrane  was  destroyed ;  the  ex- 
planation here  given  is.  as  sufficient  to  account 
for  the  existence  of  this  fluid,  as  that  which 
attributes  it  to  the  increased  secretion  of  a 
serous  membrane." 

The  membrane  is  represented  as  it  exists  in 
the  eye  of  the  sheep,  in  the  annexed  figure, 
from  my  paper  in  the  Medico-Chirurgical 
Transactions. 

Fig.  Ill, 


Mr.  Dalrymple,  in  his  valuable  work  on  the 
anatomy  of  the  eye,  takes  a  different  view  of 
the  arrangement  of  this  part  of  the  retina : 


he  says : — "  From  observations  made  on  the 
human  eye,  in  connection  with  other  expe- 
riments on  the  eyes  of  animal,  I  am  induced 
to  consider  it  as  a  double  reflected  serous  mem- 
brane. I  was  first  led  to  take  up  this  opinion 
in  the  year  1827,  by  the  accidental  observation 
of  a  very  delicate  membrane,  which  lined  and 
was  adherent  to  the  entire  choroid.  Having 
minutely  injected  the  eye  of  a  sheep,  I  made 
a  vertical  transverse  section  through  the  sclero- 
tic, choroid,  and  retina,  which  last  membrane, 
with  Jacob's  tunic,  properly  so  called,  and  the 
vitreous  body  I  removed.  I  then  placed  the 
remaining  portion  of  the  eye  in  dilute  spirits 
of  wine,  intending  to  preserve  it  for  the  ex- 
hibition of  the  tapetum,  which  in  this  instance 
was  remarkably  beautiful.  A  few  minutes 
after  its  immersion  the  tapetum  lost  to  a  con- 
siderable extent  its  brilliant  hue,  and  I  re- 
moved it  from  the  glass  to  wash  from  its  sur- 
face some  deposit,  which  I  thought  might 
have  obscured  its  polish.  In  doinjj  this,  how- 
ever, I  detached  a  delicate  membrane,  mi- 
nutely filled  with  injection,  and  this  membrane 
it  was  which  on  being  placed  in  the  spirit, 
became  slightly  opaque  and  produced  the  effect 
alluded  to  ;  for  the  tapetum  thus  denuded  in- 
stantly recovered,  and  still  retains  its  bril- 
liancy." 

The  inference  that  the  membrane  in  ques- 
tion is  a  double  reflected  serous  membrane  is 
certainly  more  in  conformity  with  analogy  than 
the  assumption  that  it  is  a  single  layer,  but  this 
uniformity  in  nature's  operations  has  been  too 
much  insisted  upon.  I  have  above  stated  my 
reasons  for  considering  it  a  single  layer,  and 
not  a  double  serous  membrane;  and  I  should  be 
inclined  to  think  that  the  layer  which  Mr.  Dal- 
rymple found  adhering  to  the  choroid  was  the 
membrane  itself,  which  had  not  come  away 
with  the  retina  and  vitreous  humour,  as  1  have 
found  sometimes  to  happen,  did  not  Mr.  Dal- 
rymple further  state  that  he  has  "  in  his  pos- 
session a  preparation,  which  does  most  dis- 
tinctly shew  the  double  portions  of  this  mem- 
brane ;  one  lining  the  choroid,  the  .other 
reflected  over  the  pulpy  structure  of  the  retina." 
Mr.  Jones,  in  the  work  formerly  alluded  to, 
gives  the  annexed  representation  of  the  mem- 
brane as  it  appears  when  Fig.  Ml. 
highly  magnified.  Fig.  113 
is  a  representation  of  the 
membrane  by  Mr.  Bauer, 
magnified  fifty  diameters,  from 
the  Philosophical  Transactions 
for  1822. 

In  the  centre  of  the  retina,  and  consequently 
in  the  axis  of  vision,  about  an  eighth  of  an 
inch  from  the  entrance  of  the  optic  nerve,  a 
very  remarkable  condition  of  structure  exists. 
This  is  a  small  point  destitute  of  cerebral  or 
medullary  fibres,  appearing  like  a  hole  in  the 
membrane,  and  hence  called  the  foramen  of 
Sommerring,  from  the  distinguished  anatomist 
who  discovered  it.  This  point  is  surrounded 
by  a  yellow  margin,  and  the  retina  is  here  also 
puckered  into  a  peculiar  form  of  fold.  Som- 
merring,  in    the  Commentationes  Societatis 


EYE. 


189 


Fig.  113. 


Regiee  Gottingenses,  gives  the  following 
account  of  the  discovery.  "  On  the  27th  of 
January,  1791,  while  I  examined  the  eyes  of  a 
very  fine  and  healthy  young  man,  a  few  hours 
previously  drowned  in  the  Rhine,  being  per- 
fectly fresh,  transparent,  and  full,  and  sup- 
ported in  an  appropriate  fluid,  with  the  in- 
tention of  exhibiting  a  perfect  specimen  of  the 
retina  to  my  pupils  in  the  anatomical  theatre, 
I  so  clearly  detected  in  the  posterior  part  of 
the  retina,  which  was  expanded  without  a 
single  fold,  on  account  of  the  perfect  state 
of  the  eye,  a  round  yellow  spot,  that  I 
was  convinced  it  was  a  natural  appearance, 
and  not  a  colour  produced  by  any  method  of 
preparation.  In  examining  this  spot  more 
accurately,  I  perceived  in  its  centre  a  little 
hole  occupying  the  situation  of  the  true  centre 
of  the  retina.  With  the  same  care  I  examined 
the  other  eye  and  found  it  exactly  similar. 
I  then  communicated  the  discovery  to  my 
pupils  in  the  public  demonstrations."  "  In  this 
precise  spot,  or  in  the  very  centre  of  the  re- 
tina, is  found  an  actual  deficiency  of  the  me- 
dullary layer,  or  a  real  hole  perfectly  round, 
with  a  defined  margin  a  fourth  of  a  line  in 
diameter."  "  The  transparent  vitreous  humour 
and  black  pigment  are  so  clearly  seen  through 


this  hole,  that  there  can  be  no  doubt  that 
it  is  a  real  aperture,  which  being  situated 
in  the  centre  of  the  retina  may  be  appro- 
priately termed  the  foramen  centrule.  Sur- 
rounding this  J'oramen  centrale  the  remark- 
able yellow  colour  resembling  that  of  gum 
guita  is  so  disposed  that  it  appears  much 
deeper  toward  the  margin,  and  totally  dis- 
appears at  a  distance  of  a  line.  This 
colour  varies  much  according  to  the  age  of 
the  individual,  being  very  faint  in  infants, 
much  deeper  at  puberty,  on  account  of  the 
thickness  and  whiteness  of  the  retina  at 
that  period,  appearing  of  a  deep  yellow 
brownish  or  crocus  colour.  In  more  ad- 
vanced age  the  colour  is  less  intense,  prin- 
cipally on  account  of  the  diminished 
whiteness  of  the  retina,  which  also  appears 
extenuated  at  that  period.  Even  the 
choroid,  where  it  corresponds  to  this  fora- 
men, sometimes  appears  a  little  deeper- 
coloured." 

In  the  paper  above  alluded  to,  published 
in  the  Medico-Chirurgical  Transactions,  I 
have  given  the  result  of  some  careful  in- 
quiries into  the  structure  of  this  part,  from 
which  the  following  observations  are  ex- 
tracted. "  Sommerring  describes  it  as  a 
hole  in  the  retina  with  a  yellow  margin, 
mentioning  as  accidental  a  fold  which 
occupies  the  situation  of  this  hole  and 
tends  to  conceal  it,  and  thus  accounting 
for  its  remaining  so  long  unnoticed.  This 
appearance  is  so  constant  and  remarkable, 
that  its  existence  may  be  very  rationally 
considered  essential  to  correct  vision,  and 
it  therefore  becomes  an  interesting  object 
of  speculation.  The  circumstances  which 
it  seems  important  to  ascertain,  are,  whe- 
ther it  is  actually  a  hole  in  the  retina  with 
a  yellow  margin ;  whether,  in  addition 
to  this  hole,  the  retina  is  folded  or  puckered  in  at 
this  part ;  or  whether  the  appearance  of  a  hole 
arises  from  a  deficiency  of  the  medullary  layer  of 
the  retina  without  any  orifice  in  its  vascular  layer. 
Both  Sommerring  himself  and  many  others  seem 
to  consider  that  the  fold  is  accidental  and  the 
consequences  of  changes  occurring  after  death. 
It  is  here  necessary  to  call  to  mind  what  those 
changes  are  with  respect  to  the  retina.  If  the 
eye  had  become  flaccid  previous  to  dissection, 
the  retina  on  being  exposed  presents  an  irre- 
gular surface,  arising  from  a  number  of  folds 
diverging  from  the  optic  nerve  as  from  a  centre, 
and  evidently  produced  by  the  loss  of  support 
from  the  partial  evaporation  of  the  fluid  of  the 
vitreous  humour.  These  folds,  however,  never 
observe  any  regular  form,  or  preserve  precise 
situations,  and  may  be  obliterated  by  changing 
the  position  of  the  eye  in  the  water.  They 
disappear  altogether  after  the  part  has  remained 
some  time  in  water,  in  consequence  of  the 
vitreous  humour  becoming  again  distended 
from  imbibing  the  fluid  in  which  it  is  im- 
mersed. It  however  requires  no  very  great 
care  or  experience  to  distinguish  between  those 
accidental  folds  and  the  peculiar  one  in  ques- 
tion. tlf  the  examination  be  made  from  with- 
out, removing  the  sclerotic  and  choroid  behind, 


190 


EYE. 


the  retina  appears  to  be  forced  or  drawn  at  tins 
point  into  the  vitreous  humour  to  the  depth 
of  about  a  twelfth  of  an  inch,  the  entire  fold 
being  something  more  than  an  eighth  in  length. 
At  first  there  is  little  or  no  appearance  of  a 
hole,  but  after  the  eye  has  remained  for  some 
time  in  the  water,  the  fold  begins  to  give  way, 
and  a  small  slit  makes  its  appearance,  which 
gradually  widens,  and  assumes  the  appearance 
of  a  round  hole.  This  hole  is  large  in  pro- 
portion to  the  degree  to  which  the  fold  has 
yielded  ;  and  when  the  fold  totally  disappears, 
as  it  sometimes  does,  the  transparent  point 
gives  the  appearance  which  Sommerring  re- 
presents, of  a  hole  with  a  yellow  margin.  If, 
instead  of  making  the  examination  in  this  way 
from  the  outside,  we  view  this  part  through 
the  vitreous  humour,  the  appearance  of  the 
hole  is  more  remarkable  ;  but  still  that  part  of 
the  retina  is  evidently  projected  forward  be- 
yond the  level  of  the  rest  of  that  membrane. 
In  the  eye  of  a  young  man,  which  I  had  an 
opportunity  of  examining  under  peculiarly 
favourable  circumstances,  within  five  hours 
after  death,  I  noticed  the  following  appear- 
ances. The  cornea  and  iris  having  been  cut 
away,  and  the  lens  removed  from  its  situation, 
I  placed  the  part  in  water,  beneath  one  of  the 
globular  glasses,  and  held  it  so  as  to  allow  the 
strong  light  of  a  mid-day  sun  to  fall  directly 
upon  it ;  when  the  retina  to  the  outside  of  the 
optic  nerve  presented  unequivocally  the  ap- 
pearance of  being  drawn  or  folded  into  the 
form  of  a  cross  or  star,  with  a  dark  speck  in 
the  centre,  surrounded  by  a  pale  yellow  areola. 
I  further  satisfied  myself  of  the  prominence 
of  the  fold  by  holding  a  needle  opposite  to  it, 
while  the  light  shone  full  upon  it,  a  shadow 
being  thus  cast  upon  the  retina  which  deviated 
from  the  straight  line  when  passed  over  the 
situation  of  the  fold.  To  ascertain  whether 
there  is  actually  a  hole  in  the  retina,  or  merely 
a  deficiency  of  nervous  matter  at  this  point, 
1  allowed  the  eye  to  remain  for  some  days  in 
water,  until  the  connexions  of  the  parts  began 
to  give  way.  I  then  introduced  a  small  probe 
between  the  retina  and  vitreous  humour,  the 
part  still  remaining  in  water,  and  bringing  the 
blunt  point  of  the  instrument  opposite  the 
transparent  spot,  attempted  to  pass  it  through, 
but  found  I  could  not  do  so  without  force 
sufficient  to  tear  the  membrane.  I  also  re- 
moved the  nervous  matter  by  maceration  and 
agitation  in  water,  and  on  floating  the  vascular 
layer,  found  that  I  could  no  longer  ascertain 
where  the  spot  had  originally  existed,  there 
being  no  hole  in  the  situation  previously  occu- 
pied by  the  transparent  speck." 

It  is  remarkable  that  the  foramen  of  Sommer- 
ring has  not  been  found  in  the  eyes  of  any  of 
the  mammalia  except  those  of  the  quudrumanu, 
in  some  of  whom  it  lias  been  detected  by  Home, 
Cuvier,  and  others,  but  the  extent  to  which  it 
may  be  traced  in  this  tribe  has  not  been  satis- 
factorily ascertained.  Dr.  Knox,  in  a  paper  in 
the  Memoirs  of  the  Wernerian  Natural  History 
Society,  announces  the  discovery  of  its  existence 
in  certain  lizards.  In  the  lacerta  superciliosa  he 
says,  "  the  retina  is  very  thick,  and  somewhat 


firm  and  opaque.  Where  the  optic  nerve  enters 
the  interior  of  the  eye-ball,  there  is  a  distinct 
marsupium  or  black  circular  body,  proceeding- 
forwards  apparently  through  the  centre  of  the 
vitreous  humour.  Anteriorly,  somewhat  supe- 
riorly and  towards  the  mesial  line  or  plane,  we 
perceive,  on  looking  over  the  surface  of  the 
retina  which  regards  the  vitreous  humour,  a 
comparatively  large  transparent,  nearly  circular 
spot,  through  which  may  be  distinguished  the 
dark-coloured  choroid.  Close  to  this  is  gene- 
rally placed  a  fold  or  reduplication  of  the  retina, 
which  is  in  general  remarkably  distinct.  This 
fold  or  folds,  (for  there  are  more  than  one) 
either  proceed  from  the  transparent  point 
towards  the  insertion  of  the  optic  nerve,  or 
close  to  it.  Sometimes  the  fold  seems,  as  it 
were,  to  lie  over  the  transparent  point,  and 
partly  to  conceal  it  from  view  ;  or  the  point  is 
formed  in  the  edge  of  the  fold  itself,  as  in  apes, 
but  in  general  the  fold  runs  directly  from 
the  insertion  of  the  optic  nerve  upwards  and 
inwards,  pressing  very  close  to  the  edge  of  the 
foramen  centrale."  The  foramen  was  also 
seen  in  the  lacerta  striata,  lacerta  calotes,  and 
others,  while  it  was  not  to  be  detected  in  the 
gecko,  crocodile,  and  some  others.  It  was  also 
subsequently  discovered  in  the  chameleon. 
The  annexed  figures  represent  the  foramen  of 
Sommerring  in  the  human  eye.  A,  shews  the 
retina  expanded  over  the  vitreous  humour  :  on 
the  right  is  the  place  from  which  the  optic 
nerve  was  cut  away,  and  from  which  the  ves- 
sels branch  out :  on  the  left  is  \he  foramen  of 
Sommerring,  represented  by  a  black  dot  sur- 
rounded by  a  dark  shade.  B,  shews  the  retina 
with  a  portion  of  the  optic  nerve.  The  exter- 
nal membrane  is  turned  down  as  in  the  pre- 
ceding representation  of  the  same  structure  in 
the  sheep's  eye,  and  the  foramen  of  Sommer- 
ring, instead  of  a  distinct  hole,  presents  the 
appearance  of  a  fold  or  depression  with  elevated 
sides.  The  wood-engraving  does  not  admit  of 
the  delicacy  of  finish  necessary  to  express  per- 
fectly this  condition  of  the  part. 


Fig.WA. 
A.  B. 


There  is  no  part  of  the  anatomy  of  the  eye 
respecting  which  there  has  been  so  much  diver- 
sity of  opinion  as  the  anterior  termination  of 
the  retina.  It  has  already  been  stated  that  it 
extends  to  the  posterior  extremities  of  the 
ciliary  processes,  where  it  is  discontinued,  pre- 
senting an  undulating  edge  corresponding  to 
the  indented  margin  of  this  part  of  the  corpus 
ciliare.  Some  assert  that  it  extends  to  the  mar- 
gin of  the  lens,  others  that  it  is  the  vascular 


EYE. 


191 


layer  only  which  extends  so  far,  and  others  that 
the  vascular  layer  extends  over  the  lens.  No 
one  however  at  present,  who  describes  from 
observation,  denies  the  termination  of  the  ner- 
vous layer  at  the  posterior  margin  of  the  ciliary 
body,  although  many  insist  upon  the  extension 
of  the  vascular  layer  to  the  circumference  of  the 
lens.    The  subject  has  received  more  attention 
„than  it  deserves,  as  it  involves  no  consideration 
of  importance,  either  physiological  or  anato- 
mical ;  but  I  am  convinced  from  a  very  care- 
ful scrutiny  that  no  such  layer  extends  between 
the  ciliary  processes  of  the  choroid  and  those  of 
the  hyaloid  membrane ;  these  two  parts  being 
mutually  inserted  into  each  other,  as  will  pre- 
sently be  explained.    In   the  paper  above 
quoted  in  the  Medico-Chirurgical  Transactions 
1  have  explained  what  appears  to  me  to  be  the 
arrangement  of  this  part  in  the  following  words  : 
"  On  removing  the  choroid,  ciliary  processes, 
and  iris,  we  see  the  retina  terminating  with  a 
denned  dentated  margin,  about  a  quarter  of  an 
inch  from  the  circumference  of  the  lens :  be- 
tween this  line  of  termination  and  the  lens,  the 
vitreous  humour  retains  upon  its  surface  part 
of  the  black  pigment  which  covered  the  ciliary 
processes.    If  the  eye  be   examined  shortly 
after  death,  removing  the  black  pigment  from 
this  part  of  the  vitreous  humour  with  a  camel- 
hair  pencil,  there  is  an  appearance  of,  at  least, 
the  vascular  layer  being  continued  to  the  lens ; 
this  part  not  being  so  transparent  as  the  rest  of 
the  hyaloid  membrane,  or  so  opaque  as  the  retina. 
From  such  an  examination  1  was  led  to  con- 
clude that  the  vascular  layer  was  continued  to 
the  margin  of  the  lens,  this  part  not  being 
so   transparent  as  the  rest  of  the  hyaloid 
membrane,  or  so  opaque  as  the  retina.  From 
such  an  examination  I  was  led  to  conclude 
that  the  vascular  layer  was  continued  to  the 
margin  of  the  lens,  but  I  adopted  a  con- 
trary opinion  after  I  had  witnessed  the  change 
which  took  place  when  the  part  had  remained 
twenty-four  hours  in  water :  the  retina  then 
separating  with  a  slight  force,  and  frequently 
detached  by  the  disturbance  given  in  making 
the  examination.  If,  after  removing  the  choroid 
without  disturbing  the  retina,  the  part  be  al- 
lowed to  remain  in  water  for  some  days,  the 
medullary  part  of  the  retina  begins  to  give 
way,  and  may  be  altogether  detached  by  agita- 
tion in  water,  leaving  the  vascular  layer  firmly 
attached  at  the  line  of  termination  just  de- 
scribed.   V\  ith  all  the  care  I  could  bestow,  I 
have,  however,  never  succeeded  in  separating 
this  layer  from  the  vitreous  humour  further.  If 
the  maceration  be  continued  for  a  few  days 
longer,  the  vascular  layer  of  the  retina  gives 
way,  the  larger  vessels  alone  remaining  attached 
at  the  original  line  of  termination  of  the  retina, 
and  appearing  to  enter  the  hyaloid  membrane 
at  this  part ;  the  appearance  which  at  first  so 
much  resembled  the  vascular  layer  proceeding 
towards  the  lens  remaining  unchanged,  being 
in  fact  part  of  the  vitreous  humour  itself.  The 
circumstance  which  has  most  strengthened  the 
notion  of  the  retina  being  continued  forward  to 
the  lens  is,  that  often  on  raising  the  choroid  and 
ciliary  processes  from  the  vitreous  humour,  we 


find  those  processes  covered  in  several  places 
by  a  fine  semi-transparent  membrane  insinuated 
between  the  folds  ;  this  is  supposed  to  be  the 
vascular  layer  of  the  retina,  but  is  really  the 
corresponding  part  of  the  hyaloid  membrane 
which  is  torn  up,  being  firmly  united  to  this 
part  of  the  choroid." 

After  this  article  had  been  prepared  for 
press,  I  received  an  admirable  monograph  upon 
the  retina  by  B.  C.  It.  Langenbeck,  son  of  the 
celebrated  professor  of  that  name  in  the  Uni- 
versity of  Gottingen,  in  which  the  nature, 
structure,  and  relations  of  this  most  important 
and  interesting  part  of  the  organ  are  subjected 
to  a  critical  and  elaborate  inquiry.  He  advo- 
cates the  membranous  nature  of  the  black  pig- 
ment on  the  inner  surface  of  the  choroid,  and 
gives  an  engraving  of  its  organization  as  ascer- 
tained by  the  microscope,  resembling  that  given 
from  the  essay  of  Mr.  Jones  in  the  preceding 
pages.  He  devotes  several  pages  to  the  de- 
scription of  the  membrane  which  I  found 
covering  the  medullary  layer  of  the  retina,  and 
adds  the  testimony  of  a  skilful  anatomist  in 
support  of  my  description,  sufficient  to  coun- 
terbalance the  convenient  scepticism  of  certain 
writers  better  skilled  in  making  plausible  books 
than  difficult  dissections.  The  fibrous  struc- 
ture of  the  medullary  layer  of  the  retina  is 
established,  and  a  plate  given  of  the  peculiar 
nodulated  condition  of  these  fibres.  The  work 
concludes  with  an  account  of  the  morbid 
changes  of  structure  observed  in  the  retina,  a 
subject  which,  notwithstanding  its  manfest 
importance,  has  not  hitherto  attracted  the  atten- 
tion which  it  deserves.  I  am  indebted  to  Dr. 
Graves  for  the  following  abstract  of  some 
recent  investigations  of  Treviranus  on  the  same 
subject.  "  From  microscopical  examinations 
Treviranus  demonstrates  that  the  cerebral  mass, 
both  medullary  and  cortical,  consists  of  hollow 
cylinders  containing  a  soft  matter.  These 
cylinders,  extremely  minute  in  the  cortical 
substance,  are  somewhat  larger  in  the  medul- 
lary, and  still  larger  in  the  nerves.  In  the 
retina  he  finds,  that  after  the  optic  nerve  has 
penetrated  the  sclerotic  and  choroid,  its  cylin- 
ders or  nervous  tubes  spread  themselves  out 
on  every  side  either  singly  or  collected  into 
bundles,  each  cylinder  or  collection  of  tubes 
bending  inwards  through  the  vascular  layer, 
and  terminating  in  the  form  of  a  papilla  on 
the  vitreous  humour." 

Of  the  vitreous  humour. — It  has  already 
been  stated  that  the  globe  of  the  eye  is 
divided  into  two  chambers  by  the  iris,  the 
posterior  of  which  is  distended  by  a  spherical 
transparent  mass  called  the  vitreous  humour, 
which  does  not  completely  fill  this  chamber 
between  the  back  of  the  iris  and  the  hollow 
sphere  of  the  retina,  but  is  discontinued  or 
compressed  at  a  short  distance  from  the  back 
of  the  iris,  having  a  narrow  space  between 
it  and  that  membrane,  called  the  posterior 
chamber  of  the  aqueous  humour.  This  trans- 
parent mass  is  composed  of  water  containing 
certain  saline  and  animal  ingredients,  deposited 
in  exquisitely  delicate  and  perfectly  transparent 
cellular  membrane ;  hence  it  is  capable  of  sus- 


192 


EYE. 


taining  its  own  weight  and  preserving  its  form 
when  placed  in  water,  and  in  air  presents  the 
appearance  of  a  gelatinous  mass,  scarcely  de- 
serving the  name  of  solid.  The  cellular  struc- 
ture, in  which  the  watery  fluid  is  lodged,  has 
been  called  the  hyaloid  membrane,  and  the 
whole  mass  denominated  the  vitreous  humour. 
The  fluid  of  the  vitreous  humour,  according 
to  Berzelius,  is  composed  of  water,  containing 
about  one  and  a  half  per  cent,  of  animal  and 
saline  ingredients;  it  has  a  saline  taste,  and 
acquires  a  slight  opaline  tint  by  being  boiled.  It 
consists  of  water  98.40,  chloruret  of  soda  with 
a  little  extractive  matter  1.42,  a  substance  solu- 
ble in  water  0.02,  and  albumen  0.16.  Its 
specific  gravity  is  1.059.  When  the  hyaloid 
membrane  is  examined  in  its  natural  state,  its 
cellular  organization  can  scarcely  be  ascertained 
on  account  of  its  transparency ;  but  if  it  be 
suspended  on  the  point  of  a  pin  until  the  fluid 
is  allowed  to  drop  out,  it  may  be  inflated  with 
a  fine  blowpipe  and  dried,  or  if  the  whole  be 
placed  in  strong  spirit  or  weak  acid,  the  mem- 
brane becomes  opaque,  and  its  organization 
obvious.  It  has  been  supposed  that  the  cells 
in  which  the  fluid  is  lodged  present  a  determi- 
nate form,  and  attempts  have  been  made  to 
prove  this  by  freezing  the  eye  and  examining 
the  frozen  fragments;  but  any  one  who  has 
seen  the  hyaloid  membrane  rendered  opaque 
by  acid  must  allow  that  the  cells  are  too  minute 
to  admit  of  such  investigation,  and  that  the 
frozen  masses,  supposed  to  be  the  contents  of 
cells,  are  merely  fragments  of  the  hyaloid 
membrane  with  their  contained  fluid.  Although 
the  hyaloid  membrane  is  perfectly  transparent, 
and  the  red  particles  of  the  blood  do  not  circu- 
late in  its  vessels,  there  can  be  little  doubt 
that  its  growth  and  nutrition  are  effected  by 
the  circulation  of  a  transparent  fluid  in  vessels 
continuous  with  those  conveying  red  blood. 
It  is  an  established  fact  that  transparent  tex- 
tures which  in  a  natural  state  do  not  exhibit 
a  trace  of  coloured  fluid,  when  excited  or 
inflamed,  become  filled  with  red  vessels,  as 
may  be  seen  in  the  conjunctiva.  It  is  there- 
fore reasonable  to  admit  that  the  hyaloid  mem- 
brane does  not  present  a  deviation  from  this 
general  law.  The  fluid  of  the  vitreous  humour, 
it  is  to  be  presumed  from  analogy,  is  secreted 
by  the  vessels  of  the  hyaloid  membrane,  and 
if  no  red  vessels  can  be  detected,  the  secretion 
must  be  accomplished  by  transparent  ones.  It 
has  already  been  stated  that  the  vascular  layer 
of  the  retina  adheres  to  the  surface  of  the 
vitreous  humour,  and  that  the  points  of  adhe- 
sion are  stronger  along  the  course  of  the  vessels 
than  in  the  intermediate  spaces ;  it  is  therefore 
most  probable  that  the  more  superficial  part  of 
the  sphere  is  supplied  with  transparent  blood 
from  the  arteries  of  the  retina,  while  a  branch 
directly  from  the  central  artery,  as  it  penetrates 
the  porus  opticus,  enters  behind,  and  extends 
to  the  back  of  the  lens :  such  a  branch  can  be 
injected  in  the  foetus,  and  is  found  to  ramify 
on  the  back  of  the  capsule  of  the  lens ;  and  in 
the  eyes  of  large  quadrupeds  a  transparent 
production,  probably  vascular,  has  been  ob- 
served proceeding  from  the  entrance  of  the 


optic  nerve  into  the  mass  of  the  vitreous 
humour.  It  is  also  probable  that  the  ciliary 
processes  of  the  choroid,  which  are  buried  in 
the  hyaloid  membrane  anteriorly,  supply  blood 
to  that  part  of  the  sphere.  That  the  vitreous 
humour  undergoes  changes  analogous  to  those 
which  take  place  in  textures  supplied  with  red 
blood,  is  proved  by  its  hyaloid  membrane 
being  found  opaque  and  thickened  in  eyes 
which  have  been  destroyed  by  internal  inflam- 
mation. A  total  disorganization  of  the  vitreous 
humour  is  a  frequent  occurrence,  the  hyaloid 
membrane  losing  its  cohesion  to  such  a  degree 
that  the  fluid  escapes  from  the  eye  as  freely  as 
the  aqueous  humour  when  the  cornea  is  divided 
in  the  operation  of  extraction ;  and  after  the 
lens  and  its  capsule  have  been  removed  by 
operations  with  the  needle,  opacity  of  the 
hyaloid  membrane  is  occasionally,  although 
rarely,  observed.  Allusion  has  frequently  been 
made  in  books  to  an  appearance  in  the 
eye  denominated  glaucoma,  attributed,  rather 
vaguely,  to  opacity  of  the  vitreous  humour;  it 
appears,  however,  to  be  nothing  more  than  the 
usual  opacity  of  the  lens  which  occurs  in 
advanced  life,  seen  through  a  dilated  pupil. 
As  an  additional  proof  of  the  vascularity  of 
the  vitreous  humour  may  be  adduced  the  fact, 
that  in  the  eyes  of  sheep,  injured  by  blows  in 
driving  to  the  shambles,  the  vitreous  humour 
is  deeply  tinged  with  red  blood. 

The  spherical  mass  of  vitreous  humour,  it 
has  already  been  stated,  is  exactly  fitted  into 
and  adheres  to  the  inner  surface  of  the  retina. 
From  the  anterior  termination  of  the  retina  to 
the  posterior  chamber  of  the  aqueous  humour, 
it  is  in  contact  with,  and  adhering  to,  the 
ciliary  processes  of  the  choroid.  Where  it  is 
truncated  or  compressed  on  its  anterior  part  to 
form  the  posterior  chamber  of  the  aqueous 
humour,  it  has  the  crystalline  lens  fitted  into  a 
depression  in  its  centre,  while  a  narrow  circle 
of  it  appears  between  the  circumference  of  the 
lens  and  the  anterior  extremities  of  the  ciliary 
processes  of  the  choroid,  forming  part  of  the 
boundaries  of  this  chamber  of  aqueous  humour. 

If  the  eye  be  allowed  to  remain  for  a  day  or 
two  in  water  in  order  to  destroy  by  maceration 
the  delicate  connexions  between  the  hyaloid 
membrane  and  the  choroid,  and  then  the 
vitreous  humour  with  the  lens  attached  care- 
fully separated,  the  point  of  a  fine  blowpipe 
may  be  introduced  under  the  surface  of  the 
hyaloid  membrane  at  the  circumference  of  the 
lens,  and  a  series  of  cells'  encircling  the  lens 
inflated.  This  is  the  canal  of  Petit,  or  canal 
godronne.  It  is  thus  described  by  the  dis- 
coverer in  the  Histoire  de  l'Academie  des 
Sciences  for  1726.  "  I  have  discovered  a  small 
canal  surrounding  the  crystalline,  which  I  call 
the  circular  canal  godronnd ;  it  can  be  seen 
only  by  inflating  it,  and  when  filled  with  air  it 
forms  itself  into  folds  similar  to  the  ornaments 
on  silver  plate,  called  for  this  reason  Vaiselle 
godronne.  It  is  formed  by  the  doubling  of  the 
hyaloid  membrane,  which  is  contracted  into 
cells  at  equal  distances  by  little  canals  which 
traverse  it,  and  which  do  not  admit  of  the 
same  degree  of  extension  as  the  membrane, 


EYE. 


193 


which  is  very  feeble;  it  thus  becomes godronne. 
If  the  crystalline  be  removed  from  its  capsule 
without  injuring  the  membrane  which  forms 
this  canal,  these  godronne  folds  are  not  formed  by 
inflation  or  only  in  a  very  slight  degree,  but  the 
canal  becomes  larger.  It  is  in  man  commonly 
a  line  and  aquarter,  aline  and  a  half  ortwo  lines 
in  breadth,  and  not  larger  in  the  ox."  An- 
nexed is  a  representation  of  this  canal  of  Petit 
on  a  large  scale. 

Fig.  115. 


Fig.  116. 


As  the  nature  of  the  connection  between 
the  choroid  and  the  hyaloid  membrane,  the 
formation  of  the  posterior  chamber  of  the 
aqueous  humour,  and  the  structure  of  this 
canal  of  Petit,  have  been  the  subject  of  contro- 
versy, I  venture  to  introduce  here  an  extract 
on  this  subject  from  the  paper  published  by 
me  in  the  Medico-Chirurgical  Transactions. 

"  If  the  sclerotic,  choroid,  iris,  and  retina 
be  removed  one  or  two  days  after  death,  leaving 
the  vitreous  humour  with  the  lens  embedded 
on  its  anterior  part,  we  observe  a  number  of 
stria  on   the  vitreous   humour,  converging 
towards  the  circumference  of  the  lens,  cor- 
responding in  number,  size,  and  form  to  the 
ciliary  processes,  giving  the  same  appearance 
collectively  that  the  circle  of  ciliary  processes 
or  corpus  ciliare  does  on  the  choroid,  and  nar- 
rowed towards  the  nasal  side  as  the  corpus 
ciliare  is.    This  appearance  has  been  noticed 
by  most  authors,   but  some  describe  it  as 
arising  merely  from  the  marks   left  by  the 
ciliary  processes,  while  others  consider  these 
stria  of  the  same  nature  as  those  productions 
of  the  choroid,  and  call  them  the  ciliary  pro- 
cesses of  the  vitreous  humour  ;  it  is  the  corona 
ciliaris  of  Camper  and  Ziun.    If  we  remove 
the  black  pigment  with  a  camel-hair  pencil,  we 
leave  those  productions  on  the  vitreous  humour 
more  distinctly  marked  than  when  covered  by 
the  colouring  matter,  and  presenting  all  the 
characters  above  stated,   commencing  behind 
with  a  well-defined  margin,  and  terminating 
anteriorly  by  attachment  to  the  capsule  of  the 
lens,  the  furrows  between  them  capable  of 
receiving  the  ciliary  processes  of  the  choroid, 
and  the  folds  calculated  to  be  lodged  in  the 
corresponding  furrows  of  these  processes.  The 
annexed  figure  is  a  representation  of  the  vitreous 
humour  of  the  human  eye  thus  treated. 


"  If  the  cornea  and  iris  be  removed  from  a 
human  eye  within  a  few  hours  after  death,  a 
dark  circle  surrounding  the  lens,  between  it 
and  the  anterior  extremities  of  the  ciliary  pro- 
cesses, may  be  observed  :  this  is  the  part  of 
the  corona  ciliaris  of  the  vitreous  humour  to 
which  the  ciliary  processes  of  the  choroid  do 
not  extend,  which  appears  dark  on  account  of 
its  perfect  transparency  ;  the  converging  strict 
are  evident,  even  on  this  part  where  the  ciliary 
processes  are  not  insinuated,  interrupting  the 
view  if  we  attempt  to  look  into  the  bottom  of 
the  eye  by  the  side  of  the  lens.  It  is,  in  my 
opinion,  therefore  certain,  that  part  of  the 
vitreous  humour  enters  into  the  formation  of 
the  posterior  chamber  of  the  aqueous  humour. 
The  demonstration  of  this  fact  is,  however, 
attended  with  difficulty,  because  the  flaccidity 
arising  from  even  slight  evaporation  of  the 
fluids  of  the  eye  permits  the  ends  of  the  ciliary 
processes  which  present  themselves  in  the 
posterior  chamber  of  the  aqueous  humour  to 
fall  towards  the  circumference  of  the  lens,  and 
appear  attached  there.  For  myself  I  can  say 
that  having  made  the  dissection  in  the  way  just 
pointed  out,  the  eye  of  course  in  water,  and 
beneath  one  of  those  globular  vessels  which 
I  formerly  described,  I  could  see  to  the  bottom 
of  the  eye  through  the  space  in  front  of  the 
vitreous  humour,  between  the  ciliary  processes 
and  the  margin  of  the  lens ;  this  space  is, 
however,  perhaps  larger  in  some  individuals 
than  in  others.  Each  fold  of  the  corona  ciliaris 
of  the  vitreous  humour  seems  to  consist  of  two 
layers  of  hyaloid  membrane,  capable  of  being 
separated  one  from  the  other  byinrlation,  and  ad- 
mitting of  communication  with  each  other  round, 
the  lens.  It  appears  to  me  that  the  canal  of  Petit 
or  canal  godronne  is  formed  in  consequence  of 
these  folds  receiving  the  injected  air  one  from 
the  other  ;  it  is,  however,  generally  described 
as  being  formed  by  the  membrane  of  the 
vitreous  humour  splitting  at  the  circumference 
of  the  lens,  one  layer  going  before  and  the 
other  behind  that  body,  the  canal  existing 
between  these  two  layers  and  the  capsule  of 
the  lens.  That  the  capsule  of  the  lens  has  no 
share  in  the  formation  of  the  canal  of  Petit,  I 
conclude  from  filling  this  canal  with  air,  and 
allowing  the  part  to  remain  for  some  days  in 
water,  and  then  with  great  care  removing  the 
lens  included  in  its  capsule;  this  I  do  not  find, 
however,  causes  the  air  to  escape  from  the  cells, 
but  leaves  them  presenting  nearly  the  original 
appearance ;  and  after  the  air  has  escaped,  I 
can  pass  a  small  probe  all  round  in  this  canal, 


194 


EYE. 


raising  by  this  means  the  folds  from  the  hyaloid 
membrane.  It  is  difficult,  however,  to  pre- 
serve the  air  in  these  folds  for  any  length  of 
time  under  water,  because  the  tendency  of 
the  air  to  ascend  causes  the  rupture  of  the 
membrane,  by  which  it  is  allowed  to  escape. 
After  the  lens,  included  in  its  proper  capsule, 
has  been  detached  from  its  situation  on  the 
vitreous  humour,  the  space  it  occupied  pre- 
sents the  appearance  of  a  circular  depression, 
surrounded  by  those  productions  of  the  hyaloid 
membrane  of  which  I  have  just  spoken ;  the 
vitreous  humour  remaining  in  every  respect 
perfect,  notwithstanding  this  abstraction  of  the 
lens." 

M.  Ribes,  in  the  Memoires  de  la  Societe" 
Medicale  d'Emulation  for  1816,  describes  the 
ciliary  processes  of  the  vitreous  humour  as 
follows.  "  At  the  anterior  part  of  the  vitreous 
humour,  and  at  a  short  distance  from  the  cir- 
cumference of  the  crystalline,  may  be  seen  a 
ciliary  body  almost  altogether  similar  to  that 
of  the  choroid,  and  which  has  been  named  by 
anatomists  corona  ciliaris,  but  no  writer  has 
hitherto  pointed  out  its  structure,  or  the  impor- 
tant office  it  appears  to  perform.  Each  of 
these  processes  has  a  margin  adherent  to  the 
vitreous  humour,  and  encroaches  a  little  on  the 
circumference  of  the  lens.  It  appears  to  me 
impossible  to  ascertain  whether  the  surfaces  are 
reticulated,  but  they  are  villous.  The  free 
margin  is  obviously  fringed,  and  presents 
nearly  the  variety  of  appearance  observed  in 
the  fringes  of  ciliary  processes  (of  the  choroid) 
of  different  animals  examined  by  me,  except 
that  the  summits  are  black  ;  the  interval  which 
separates  each  process  of  the  vitreous  humour 
is  a  species  of  depressed  transparent  gutter. 
The  black  colour  of  the  free  margins  and  the 
transparency  of  the  space  which  separates  each 
ciliary  process  adorns  the  anterior  part  of  the 
vitreous  humour  with  a  circle  remarkable  for 
its  agreeable  effect,  and  which  has  been  com- 
pared to  the  disc  of  a  radiated  flower."  Dr. 
Knox,  in  a  communication  made  to  the  Royal 
Society  of  Edinburgh,  at  the  same  time  that 
mine  was  made  to  the  Medico-Chirurgical 
Society,  describes  the  ciliary  processes  of  the 
choroid  as  follows :  "  In  whatever  way,  the 
membrane  or  assemblage  of  membranes  pro- 
ceeds forwards  to  be  inserted  into  the  circum- 
ference of  the  capsule  of  the  lens,  forming  in 
its  passage  numerous  longitudinal  folds,  and 
small  projecting  fimbriated  bodies,  by  which, 
in  a  natural  state,  the  transparent  humours  are 
connected  with  the  superjacent  ciliary  body  (of 
the  choroid) ;  when  examined  with  a  good 
glass,  these  folds  are  remarkably  distinct,  and 
the  whole  bears  the  closest  resemblance  in  its 
distribution  to  the  true  ciliary  body  and  pro- 
cesses. I  have,  therefore,  ventured  to  call 
them  the  internal  or  transparent  ciliary  body, 
or  the  ciliary  body  of  the  hyaloid  membrane, 
in  contradistinction  to  that  of  the  choroid."  It 
must  not  be  forgotten  that  these  ciliary  pro- 
cesses of  the  hyaloid  membrane  were  described 
by  Monro  in  his  Treatise  on  the  Eye,  and  are 
strongly  marked  in  a  coarsely  executed  plate. 
He  considered  that  the  retina  was  continued  to 


the  lens,  and  describes  its  course  under  the 
ciliary  processes  of  the  choroid ;  thus  "  on  ex- 
amining the  retina  with  still  greater  accuracy, 
it  appears  that  it  has  exactly  the  same  number 
of  folds  or  doublings  that  the  choroid  coat  has; 
for  it  enters  double  between  the  ciliary  pro- 
cesses, nearly  in  the  same  way  that  the  pia 
mater  enters  into  the  coats  of  the  brain.  The 
furrows  and  doublings  of  the  retina,  which,  if 
we  are  to  use  the  favourite  term  ciliary,  may 
be  called  its  ciliary  processes,  make  an  impres- 
sion on  the  anterior  part  of  the  vitreous  hu- 
mour." The  structure  alluded  to  was  also 
observed  by  Hovius  nearly  an  hundred  years 
before. 

From  the  preceding  observations  respecting 
the  ciliary  processes  of  the  vitreous  humour,  it 
may  justly  be  inferred  that  the  ciliary  pro- 
cesses of  the  choroid,  and  these  ciliary  pro- 
cesses of  the  vitreous  humour,  are  of  the  same 
nature,  differing  only  in  those  of  the  choroid 
receiving  red  blood,  while  those  of  the  vitreous 
humour  receive  a  transparent  fluid  by  their 
bloodvessels.  The  adaptation  of  these  two 
circles  of  folds  to  each  other  appears  to  be  a 
most  beautiful  example  of  mechanical  con- 
struction occurring  in  soft  parts :  it  is  a  species 
of  dovetailing  of  the  one  structure  into  the 
other,  by  which  an  intimate  union  is  secured 
between  one  part  of  considerable  strength  and 
another  of  extreme  delicacy.  A  connexion 
equally  perfect  is  established  between  the  ex- 
ternal surface  of  the  choroid  at  its  margin,  and 
the  corresponding  margin  of  the  sclerotic,  by 
means  of  the  ciliary  ligament;  in  fact,  with- 
out these  two  provisions  of  ciliary  ligament 
and  ciliary  processes,  and  their  application 
between  the  sclerotic,  choroid,  and  vitreous 
humour,  the  chambers  of  the  eye  must  be 
imperfectly  constructed,  and  the  optical  me- 
chanism of  the  organ  defective.  It  is  the 
mechanical  bond  between  these  dissimilar  parts 
which  perfects  the  chamber  of  aqueous  humour, 
and  prevents  that  fluid  from  escaping,  either 
between  the  sclerotic  and  choroid,  or  between 
the  choroid  and  vitreous  humour. 

Of  the  crystalline  leiis. — It  has  been  al- 
ready stated,  that  there  is  a  double  convex 
lens  within  the  sphere  of  the  eye,  at  a  short 
distance  behind  the  external  lens  or  cornea. 
This  is  the  crystalline  lens  or  crystalline 
humour,  which  gives  additional  convergence 
to  the  rays  of  light  transmitted  through  the 
pupil.  It  is  placed  in  a  depression,  formed  for 
its  reception  on  the  anterior,  compressed,  or 
truncated  portion  of  the  vitreous  humour, 
where  that  body  approaches  the  back  of  the 
iris,  and  constitutes  part  of  the  boundaries  of 
the  posterior  chamber  of  the  aqueous  humour. 
In  this  depression  it  adheres  firmly  to  the  hya- 
loid membrane,  and  from  the  vessels  of  that 
structure  derives  its  nutriment. 

This  double  convex  lens  does  not  present  the 
same  curvature  on  both  surfaces,  the  anterior 
being  less  curved  than  the  posterior,  in  the 
ratio  of  about  4  to  3-  Attempts  have  been  made 
to  determine  with  accuracy  the  nature  of  these 
curvatures,  first  by  Petit,  and  subsequently  by 
Wintringham,  Chossat,  and  others.    The  re- 


EYE. 


195 


suits  of  the  numerous  experiments  of  Petit  lead 
to  the  conclusion,  that  the  anterior  curvature  is 
that  of  a  portion  of  a  sphere  from  six  to  seven 
lines  and  a  half  in  diameter,  the  posterior  that  of 
a  sphere  of  from  five  to  six  lines  and  a  quarter. 
From  the  same  source  it  appears  that  the  dia- 
meter is  from  four  lines  to  four  lines  and  a  half, 
the  axis  or  thickness  about  two  lines,  and  the 
weight  three  or  four  grains.  I  am,  however, 
inclined  to  agree  with  the  observation  of  Porter- 
field,  that,  "  as  it  is  scarce  possible  to  measure 
the  crystalline  and  the  other  parts  of  the  eye 
with  that  exactness  that  may  be  depended  on, 
all  nice  calculations  founded  on  such  measures 
must  be  fallacious  and  uncertain,  and,  therefore, 
should,  for  the  most  part,  be  looked  on  rather 
as  illustrations  than  strict  demonstrations  of  the 
points  in  question."  The  method  by  which 
Petit  arrived  at  these  results  must  render  them 
of  doubtful  value,  the  curvatures  having  been 
determined  by  the  application  of  brass  plates 
cut  to  the  requisite  form.  The  results  of 
Chossat's  experiments,  conducted  with  great 
care,  and  with  the  assistance  of  the  megascope, 
are  thus  stated  by  Mr.  Lloyd  in  his  Treatise  on 
Optics :  "  This  author  has  found  that  the  cornea 
of  the  eye  of  the  ox  is  an  ellipsoid  of  revolution 
round  the  greater  axis,  this  axis  being  inclined 
inwards  about  10°.  The  ratio  of  the  major 
axis  to  the  distance  between  the  foci  in  the 
generating  ellipse  he  found  to  be  1.3  ;  and  this 
agreeing  very  nearly  with  1.337,  the  index  of 
refraction  of  the  aqueous  humour,  it  follows 
that  parallel  rays  will  be  refracted  to  a  focus,  by 
the  surface  of  this  humour,  with  mathemathical 
accuracy.  The  same  author  found  likewise  that 
the  two  surfaces  of  the  crystalline  lens  are  ellip- 
soids of  revolution  round  the  lesser  axis  ;  and  it  is 
somewhat  remarkable  that  the  axes  of  these  sur- 
faces do  notcoincide  in  direction  either  with  each 
other,  or  with  the  axis  of  the  cornea,  these  axes 
being  both  inclined  outwards,  and  containing 
with  each  other,  in  the  horizontal  section  in 
which  they  lie,  an  angle  of  about  5P."  It  must 
not  be  forgotten  that  these  observations  apply 
to  the  crystalline  of  the  ox,  not  to  that  of  man, 
and  also  that,  as  Chossat  himself  admits,  the 
evaporation  of  the  fluid  part  of  the  lens,  or  the 
absorption  or  imbibition  of  the  water  in  which 
it  is  immersed,  may  materially  alter  the  curva- 
ture. I  cannot  myself  believe  it  possible  to 
separate  a  fresh  lens  in  its  capsule  perfectly 
from  the  hyaloid  membrane  without  injuring 
its  structure,  and  endangering  an  alteration  in 
its  form.  Haller  states  that  Kepler  considered 
the  anterior  convexity  to  approach  to  a  sphe- 
roid, and  the  posterior  to  a  hyperbolic  cone. 
Wintringham  states  the  results  of  his  inquiries 
as  to  this  matter  as  follows : — "  In  order  to 
take  the  dimensions  of  the  eye  of  an  ox,  I 
placed  it  on  a  horizontal  board  and  applied 
three  moveable  silks,  which  were  kept  extended 
by  small  plummets,  so  as  to  be  exact  tangents 
to  the  arch  of  the  cornea,  as  well  at  each  can- 
thus,  as  at  the  vertex ;  then  applying  a  very 
exactly  divided  scale,  I  found  that  the  chord  of 
the  cornea  was  equal  to  1 .05  of  an  inch,  the 
versed  sine  of  this  chord  to  be  0.29,  and  con- 
sequently the  radius  of  the  cornea  was  equal  to 
0.620215  of  an  inch.    I  then  carefully  took  off 


the  cornea,  and  replaced  the  eye  as  before,  and 
found,  by  applying  one  of  the  threads  as  a  tan- 
gent to  the  vertex  of  the  crystalline,  that  the 
distance  between  this  and  the  vertex  of  the  cor- 
nea was  0.355  of  an  inch.  Afterwards  I  took 
the  crystalline  out  without  injuring  its  figure, 
or  displacing  the  capsula,  and  then  applying 
the  threads  to  each  surface  of  this  humour,  as 
was  done  before  to  the  arch  of  the  cornea,  I 
found  that  the  chord  of  the  crystalline  was  0.74 
of  an  inch,  and  its  versed  sine,  with  respect  to 
the  anterior  surface,  to  be  0.189  of  an  inch,  and 
consequently  the  radius  of  this  surface  was 
0.45665  of  the  same.  In  like  manner  the 
versed  sine  to  the  same  chord,  with  respect  to 
the  posterior  surface  of  the  crystalline,  I  found 
to  be  equal  to  0.38845  of  an  inch.  Lastly,  I 
found  the  axis  of  the  crystalline  and  that  of  the 
whole  eye  from  the  cornea  to  the  retina  to  be 
0.574,  2.21  respectively.'"  Whatever  doubts 
may  be  entertained  respecting  the  accuracy  of 
the  measurements  of  the  lens,  there  can  be  none 
that  the  form  is  different  at  different  periods  of 
life,  in  the  human  subject.  It  also  appears  to 
differ  in  different  individuals  at  the  same  period 
of  life,  and  probably  the  curvature  is  not  the 
same  in  both  eyes.  In  other  animals  the  dif- 
ference in  form  is  most  remarkable.  In  the 
human  fetus,  even  up  to  the  ninth  month,  it  is 
almost  spherical.  Petit  states  that  he  found 
the  anterior  curvature  in  a  fetus  of  seven 
months,  a  portion  of  a  sphere  of  three  lines 
diameter,  and  the  posterior  of  two  and  a  half, 
and  the  same  in  a  new-born  infant.  In  an  in- 
fant eight  days  old,  the  anterior  convexity  was 
a  portion  of  a  sphere  of  four  lines,  and  the 
posterior  of  three.  All  anatomists  concur  in 
considering  the  lens  to  approach  more  to  a 
sphere  at  this  period.  In  childhood  the  curva- 
tures still  continue  much  greater  than  in  ad- 
vanced life ;  from  ten  to  twenty  probably  de- 
crease, and  from  that  period  to  forty,  forty-five, 
or  fifty,  remain  stationary,  when  they  become 
much  less;  being,  according  to  the  tables  of 
Petit,  portions  of  spheres  from  seven  to  even 
twelve  lines  in  diameter,  and  on  the  posterior 
of  six  or  eight.  Every  day's  observation  proves 
that  the  lens  becomes  flattened,  and  its  curva- 
tures diminished  as  persons  advance  in  life.  It 
is  seen  in  dissection,  when  extracted  by  opera- 
tion, and  even  during  life;  the  distance  between 
its  anterior  surface  and  the  back  of  the  iris  be- 
ing so  great  in  some  old  persons,  that  the  sha- 
dow of  the  pupil  may  be  seen  upon  it,  while  at 
an  earlier  period  it  actually  touches  that  part  of 
the  membrane.  This  diminution  of  the  curva- 
tures of  the  lens  commences  about  the  age  of 
forty-five.  Petit  found  the  anterior  convexity 
varying  from  a  sphere  of  about  seven  to  twelve 
lines  diameter,  and  the  posterior  from  fire  to 
eight  in  persons  from  fifty  to  sixty-five  years  of 
age.  The  alteration  in  power  of  adaptation, 
and  the  indistinctness  of  vision  of  near  objects 
which  takes  place  at  this  period,  is  probably  to 
be  attributed  to  this  cause,  although  a  diminu- 
tion of  the  muscular  power  of  the  iris,  and  con- 
sequent inactivity  of  the  pupil,  may  contribute 
to  the  defect.  It  is  also  to  be  recollected  that 
the  density  of  the  lens  is  much  increased  at  this 
period,  and  that  the  young  person  whose  lens 

o  2 


196 


EYE. 


presents  greater  curvatures  does  not  require 
concave  glasses,  as  the  old  person  requires  con- 
vex ones.  The  state  of  the  eye,  after  the  re- 
moval of  the  lens  by  operation  for  cataract, 
proves  that  it  is  a  part  of  the  organ  essentially 
necessary  for  correct  vision.  When  the  eye  is 
in  other  respects  perfect,  without  any  shred  of 
opaque  capsule, any  irregularity  or  adhesion  of 
the  pupil,  or  any  alteration  in  the  curvature  of 
the  cornea,  as  in  young  persons  who  have  had 
the  lens  properly  broken  up  with  a  fine  needle 
through  the  cornea,  vision  is  so  good  for  distant 
objects,  that  such  persons  are  able  to  pursue 
their  common  occupations,  and  walk  with  safety 
through  crowded  streets,  but  they  require  the 
use  of  a  convex  lens,  of  from  three  and  a  half  to 
five  inches  focus,  for  reading  or  vision  of  near ; 
old  persons,  however,  generally  require  convex 
glasses  on  all  occasions  after  the  removal  of  the 
lens.  That  the  curvatures  of  the  lens  are  fre- 
quently different  in  different  individuals  may 
be  inferred  from  the  frequency  of  short  sight, 
or  defective  power  of  adaptation,  not  attributa- 
ble to  any  peculiarity  of  the  cornea.  Petit 
states  that  he  found  lenses  of  which  the  two 
convexities  were  equal,  and  others  of  which  the 
anterior  was  greater  than  the  posterior,  and 
more  than  once,  one  more  convex  on  its  ante- 
rior surface  in  one  eye,  while  that  in  the  other 
eye  was  in  a  natural  state.  He  also  occasion- 
ally found  the  lens  as  convex  in  the  advanced 
period  of  life  as  in  youth.  I  have  repeatedly 
observed  the  perfection  of  vision  and  power  of 
adaptation  much  greater  in  one  eye  than  the 
other  in  the  same  individual,  without  any  defect 
of  the  cornea,  pupil,  or  retina ;  and  occasionally 
have  found  young  persons  requiring  the  com- 
mon convex  glasses  used  by  persons  advanced 
in  life,  and  old  persons  becoming  near-sighted, 
and  requiring  concaves.  The  annexed  letters 
shew  the  difference  of  curvature  at  the  different 
periods  of  life,  as  represented  by  Sbmmerring. 
A  is  the  lens  of  the  foetus;  B,  that  of  a  child  of 
six  years  of  age ;  and  C,  that  of  an  adult. 

Fig.  117. 


ABC 


The  colour  of  the  lens  is  also  different  at 
different  periods  of  life.  In  the  foetus  it  is 
often  of  a  reddish  colour;  at  birth  and  in  in- 
fancy it  appears  slightly  opaque  or  opaline  ;  in 
youth  it  is  perfectly  transparent;  and  in  the 
more  advanced  periods  of  life  acquires  a  yel- 
lowish or  amber  tint.  These  varieties  in  colour 
are  not  visible,  unless  the  lens  be  removed 
from  the  eye,  until  the  colour  becomes  so  deep 
in  old  age  as  to  diminish  the  transparency, 
when  it  appears  opaque  or  milky,  or  resembling 
the  semitransparent  horn  used  for  lanterns.  The 
hard  lenticular  cataract  of  advanced  life  appears 
to  be  nothing  more  than  the  extreme  of  this 
change  of  colour,  at  least  when  extracted  and 
placed  on  white  paper  it  presents  no  other 
disorganization ;  but  the  lens  of  old  persons, 
when  seen  in  a  good  light  and  with  a  dilated 
pupil,  always  appears  more  or  less  opaque,  al- 


though vision  remains  perfect.  The  depth  of 
colour  is  sometimes  so  great,  without  any 
milkiness  or  opacity,  that  the  pupil  appears 
quite  transparent  although  vision  is  lost.  This 
is  perhaps  the  state  of  lens  vaguely  alluded  to 
by  authors  under  the  name  of  black  cataract. 

The  consistence  of  the  lens  varies  as  much 
as  its  colour.  In  infancy  it  is  soft  and  pulpy, 
in  youth  firmer,  but  still  so  soft  that  it  may  be 
crushed  between  the  finger  and  thumb,  and  in 
old  age  becomes  tough  and  firm.  Hence  it  is 
that  in  the  earlier  periods  of  life  cataracts  may 
be  broken  up  completely  into  a  pulp,  and 
absorbed  with  certainty,  while  in  old  persons 
they  adhere  to  the  needle,  unless  very  deli- 
cately touched,  and  are  very  liable  to  be  de- 
tached from  the  capsule  and  thrown  upon  the 
iris,  causing  the  destruction  of  the  organ.  On 
this  account,  therefore,  the  operation  of  extrac- 
tion must  generally  be  resorted  to  in  old  per- 
sons labouring  under  this  form  of  cataract, 
while  the  complete  division  of  it  with  the 
needle  and  exposure  of  the  fragments  to  the 
contact  of  the  aqueous  humour  secures  its 
removal  by  absorption  in  young  persons.  It 
must  not,  however,  be  forgotten  that  the  softer 
lenticular  cataract  occasionally  occurs  in  ad- 
vanced life. 

The  crystalline  lens  is  a  little  heavier  than 
water.  Porterfield,  from  the  experiments  of 
Bryan  Robinson,  infers  that  the  specific  gra- 
vity of  the  human  lens  is  to  that  of  the  other 
humours  as  eleven  to  ten,  the  latter  being 
nearly  the  same  as  water;  'and  W.intringham, 
from  his  experiments,  concludes  that  the  den- 
sity of  the  crystalline  is  to  that  of  the  vitreous 
humour  in  the  ratio  of  nine  to  ten;  the  spe- 
cific gravity  of  the  latter  being  ;to  water  as 
10024  to  10000.  The  density  of  the  lens  is 
not  the  same  throughout,  the  surface  being 
nearly  fluid,  while  the  centre  scarcely  yields  to 
the  pressure  of  the  finger  and  thumb,  especially 
in  advanced  life.  Wintringham  found  the  spe- 
cific gravity  of  the  centre  of  the  lens  of  the  ox 
to  exceed  that  of  the  entire  lens  in  the  propor- 
tion of  twenty-seven  to  twenty-six.  The  re- 
fractive power  is  consequently  greater  than  that 
of  the  other  humours.  On  this  head  Mr. 
Lloyd,  in  his  Optics,  says,  "  In  their  refrac- 
tive power,  the  aqueous  and  vitreous  humours 
differ  very  little  from  that  of  water.  The  re- 
fractive index  of  the  aqueous  humour  is  1.337, . 
and  that  of  the  vitreous  humour  1.339;  that  of 
water  being  1.336.  The  refractive  power  of 
the  crystalline  is  greater,  its  mean  refracting 
index  being  1.384.  The  density  of  the  crystal- 
line, however,  is  not  uniform,  but  increases 
gradually  from  the  outside  to  the  centre.  This 
increase  of  density  serves  to  correct  the  aber- 
ration by  increasing  the  convergence  of  the 
central  rays  more  than  that  of  the  extreme  parts 
of  the  pencil."  Dr.  Brewster,  in  his  Treatise 
on  Optics,  says,  "  I  have  found  the  following 
to  be  the  refractive  powers  of  the  different 
humours  of  the  eye,  the  ray  of  light  being 
incident  upon  them  from  the  eye :  aqueous 
humour  1.336;  crystalline,  surface  1.3767, 
centre  1.3990,  mean  1.3839;  vitreous  humour 
1.3394.  But  as  the  rays  refracted  by  the 
aqueous  humour  pass  into  the  crystalline,  and 


EYE. 


L97 


tliose  from  the  crystalline  into  the  vitreous 
humour,  the  indices  of  refraction  of  the  sepa- 
rating surface  of  these  humours  will  be,  from 
the  aqueous  humour  to  the  outer  coat  of  the 
crystalline  1.0466,  from  the  aqueous  humour 
to  the  crystalline,  using  the  mean  index,  1.0353, 
from  the  vitreous  to  the  outer  coat  of  the  cry- 
stalline 1.0445,  from  the  vitreous  to  the  crystal- 
line, using  the  mean  index,  1.0332."  Dr. 
Young  says,  "  On  the  whole  it  is  probable 
that  the  refractive  power  of  the  centre  of  the 
human  crystalline,  in  its  living  state,  is  to  that 
of  water  nearly  as  18  to  7;  that  the  water  im- 
bibed after  death  reduces  it  to  the  ratio  of  21  to 
20 ;  but  that  on  account  of  the  unequable  den- 
sity, its  effect  in  the  eye  is  equivalent  to  a 
refraction  of  14  to  13  for  its  whole  size." 

Respecting  the  chemical  composition  of  the 
lens,  Berzelius  observes,  that  "  the  liquid  in 
its  cells  is  more  concentrated  than  any  other 
in  the  body.  It  is  completely  diaphanous  and 
colourless,  holding  in  solution  a  particular 
animal  matter  belonging  evidently  to  the  class 
of  albuminous  substances,  but  differing  from 
fibrine  in  not  coagulating  spontaneously,  and 
from  albumen,  inasmuch  as  the  concentrated 
solution,  instead  of  becoming  a  coherent  mass 
on  the  application  of  heat,  becomes  granulated 
exactly  as  the  colouring  matter  of  the  blood 
when  coagulated,  from  which  it  only  differs  in 
the  absence  of  colour.  All  those  chemical 
properties  are  the  same  as  those  of  the  co- 
louring matter  of  the  blood.  The  following 
are  the  principles  of  which  the  lens  is  com- 
posed :  peculiar  coagulable  albuminous  matter 
35.9,  alcoholic  extract  with  salts  2.4,  watery 
extract  with  traces  of  salts  1.3,  membrane  form- 
ing the  cells  2.4,  water  58.0. 

From  the  preceding  observations  it  might 
reasonably  be  supposed  that  the  lens  is  com- 
posed of  a  homogeneous  material,  such  as  al- 
bumen or  gelatine,  more  consolidated  in  the 
centre  than  at  the  circumference ;  but  this  is 
not  the  case ;  on  the  contrary,  it  exhibits  as 
much  of  elaborate  organization  as  any  other 
structure  in  the  animal  economy.  It  consists 
of  an  outer  case  or  capsule,  so  totally  different 
from  the  solid  body  contained  within  it,  that 
they  must  be  separately  investigated  and  de- 
scribed. The  body  of  the  lens,  it  has  been 
already  stated,  consists  of  certain  saline  and 
animal  ingredients  combined  with  more  than 
their  weight  of  water,  and  when  perfectly 
transparent  presents  the  appearance  of  a  tena- 
cious unorganized  mass;  but  when  rendered 
opaque  by  disease,  loss  of  vitality,  heat,  or  im- 
mersion in  certain  fluids,  its  intimate  structure 
becomes  visible.  If  the  lens  with  the  capsule 
attached  to  the  hyaloid  membrane  be  removed 
from  the  eye  and  placed  in  water,  the  following 
day  it  is  found  slightly  opaque  or  opaline,  and 
split  into  several  portions  by  fissures  extending 
from  the  centre  to  the  circumference,  as  seen 
in  fig.  118.  This  appearance  is  rendered 
still  more  obvious  by  immersion  in  spirit,  or 
the  addition  of  a  few  drops  of  acid  to  the 
water.  If  a  lens  thus  circumstanced  be  al- 
lowed to  remain  some  days  in  water,  it  con- 
tinues to  expand  and  unfold  itself,  and  if 
delicately  touched  and  opened  by  the  point  of 


a  needle,  and  carefully  transferred  to  spirit, 
and  as  it  hardens  is  still  more  unravelled  by 
dissection,  it  ultimately  presents  a  remarkable 
fibrous  or  tufted  appearance,  as  represented  in 
the  figure  below,  drawn  by  me  some  years  ago 
from  a  preparation  of  the  lens  of  a  fish  thus 
treated  (the  Lophius  piscatorius ).  The  three 
annexed  figures  represent  the  structure  of  the 
lens  above  alluded  to:  A  is  the  human  crystal- 
line in  its  natural  state;  B,  the  same  split  up  into 
its  component  plates  ;  and  C,  unravelled  in 
the  fish. 

Fig.  118. 

C 


This  very  remarkable  structure  of  the  body 
of  the  lens  appears  to  have  been  first  accu- 
rately described  by  Leeuwenhoek,  subse- 
quently by  Dr.  Young,  and  still  more  recently 
by  Sir  David  Brewster.  Leeuwenhoek  says, 
"  It  may  be  compared  to  a  small  globe  or 
sphere,  made  up  of  thin  pieces  of  paper  laid 
one  on  another,  and  supposing  each  paper  to 
be  composed  of  particles  or  lines  placed  some- 
what in  the  position  of  the  meridian  lines  on  a 
globe,  extending  from  one  pole  to  the  other." 
Again  he  says,  "  With  regard  to  the  before- 
mentioned  scales  or  coats,  I  found  them  so 
exceedingly  thin,  that,  measuring  them  by  my 
eye,  I  must  say  that  there  were  more  than  two 
thousand  of  them  lying  one  upon  another." 
"  And,  lastly,  I  saw  that  eacjj^of  these  coats 
or  scales  was  formed  of  filaments  or  threads 
placed  in  regular  order,  side  by  side,  each  coat 
being  the  thickness  of  one  such  filament."  The 
peculiar  arrangement  of  these  fibres  he  describes 
as  follows  :  "  Hence  we  may  collect  how  ex- 
cessively thin  these  filaments  are;  and  we  shall 
be  struck  with  admiration  in  viewing  the  won- 
derful manner  they  take  their  course,  not  in  a 
regular  circle  round  the  ball  of  the  crystalline 
humour,  as  I  first  thought,  but  by  three  dif- 
ferent circuits  proceeding  from  the  point  L, 
which  point  I  will  call  their  axis  or  centre. 
They  do  not  on  the  other  side  of  the  sphere 
approach  each  other  in  a  centre  like  this  at  L, 
but  return  in  a  short  or  sudden  turn  or  bend, 
where  they  are  the  shortest,  so  that  the  filaments 
of  which  each  coat  is  composed  have  not  in  reality 
any  termination  or  end.  To  explain  this  more 
particularly,  the  shortest  filaments,  M  K,  H  N, 
and  O  F,  which  fill  the  space  on  the  other 
side  of  the  sphere,  constitute  a  kind  of  axis  or 
centre,  similar  to  this  at  L,  so  that  the  fila- 
ments M  K,  having  gone  their  extent,  and  filled 
up  the  space  on  the  other  side,  in  like  manner 
as  is  here  shewn  by  the  lines  ELI,  return 
back  and  become  the  shortest  filaments  H  N. 
These  filaments  H  N,  passing  on  the  other  side 


198 


EYE. 


of  the  spheve,  again  form  another  axis  or  centre, 
and  return  in  the  direction  O  F,  and  the  fila- 
ments O  F,  again  on  the  other  side  of  the 
sphere,  collect  round  a  third  centre,  and  thence 
return  in  the  direction  K  M ;  so  that  the  fila- 
ments which  are  on  this  side  of  the  sphere 
collect  round  a  third  centre,  and  thence  return 
in  the  direction  KM;  so  that  the  filaments 
which  are  on  this  side  the  shortest,  on  the  other 
side  are  the  longest,  and  those  which  there  are 
the  shortest  are  here  the  longest."  Annexed  is 
Leeuwenhoek's  representation  (fig.  119). 

Fig.  119. 


Dr.  Young  differs  from  Leeuwenhoek  as  to 
the  arrangement  of  the  fibres  and  other  parti- 
culars, and  in  his  last  paper  corrects  the  de- 
scription given  by  himself  in  a  former  one  ;  he 
says,  "  The  number  of  radiations  (of  the  fibres) 
is  of  little  consequence ,  but  I  find  that  in  the 
human  crystalline  there  are  ten  on  each  side, 
not  three,  as  I  once  from  a  hasty  observation 
concluded."  "  In  quadrupeds  the  fibres  at 
their  angular  meeting  are  certainly  not  conti- 
nued as  Leeuwenhoek  imagined."  Beneath  is 
Dr.  Young's  last  view  of  the  arrangement  of 
the  fibres,  which  Dr.  Brewster  has  shown  to  be 
incorrect,  but  the  introduction  of  which  is  jus- 
tified by  the  source  from  which  it  is  derived. 


Fig.  120. 


Sir  David  Brewster  says  that  the  direction  of 
the  fibres  is  different  in  different  animals;  the 
simplest  arrangement  being  that  of  birds,  and 
the  cod,  haddock,  and  several  other  fishes.  In 
it  the  fibres,  like  the  meridians  of  a  globe,  con- 
verge to  two  opposite  points  of  a  spheroidal  or 
lenticular  solid,  as  in  the  annexed  figure. 


Fig.  121. 


The  second  or  next  simplest  structure  he 
detected  in  the  salmon,  shark,  trout,  and  other 
fishes  ;  as  well  as  in  the  hare,  rabbit,  and  por- 
poise among  the  mammalia;  and  in  the  alli- 
gator, gecko,  and  others  among  reptiles.  Such 
lenses  have  two  septa  at  each  pole,  as  in  the 
annexed  figure. 

% 

Fig.  122. 


The  third  or  more  complex  structure  exists 
in  mammalia  in  general,  "  in  which  three  septa 
diverge  from  each  pole  of  the  lens,  at  angles  of 
120°,  the  septa  of  the  posterior  surface  bisect- 
ing the  angles  formed  by  the  septa  of  the  ante- 
rior surface,  as  in  the  annexed  figure (7?g.l23). 


EYE. 


199 


Fig.  123. 


The  mode  in  which  these  fibres  are  laterally 
united  to  each  other  is  equally  curious.  Sir 
David  Brewster  says  that  he  ascertained  this  in 
looking  at  a  bright  light  through  a  thin  lamina 
of  the  lens  of  a  cod,  when  he  observed  two 
faint  and  broad  prismatic  images,  situated  in  a 
line  exactly  perpendicular  to  that  which  joined 
the  common  coloured  images.  Their  angular 
distance  from  the  central  image  was  nearly  five 
times  greater  than  that  of  the  first  ordinary 
prismatic  images,  and  no  doubt  whatsoever 
could  be  entertained  that  they  were  owing  to  a 
number  of  minute  lines  perpendicular  to  the 
direction  of  the  fibres,  and  whose  distance  did 
not  exceed  the  jj&dth  of  an  inch.  Upon  ap- 
plying a  good  microscope  to  a  well-prepared 
lamina,  the  two  fibres  were  found  united  by  a 
series  of  teeth  exactly  like  those  of  rack  work, 
the  projecting  teeth  of  one  fibre  entering  into 
the  hollows  between  the  teeth  of  the  adjacent 
one,  as  in  fig.  124. 

Fig.  124. 


I  have  said  that  the  lens  consists  of  an  outer 
case  or  capsule  totally  different  from  the  solid 


body  contained  within  it.  This  capsule  is 
strong,  elastic,  and  perfectly  transparent.  In 
the  paper  to  which  I  have  alluded  in  the  Me- 
dico-Chirurgical  Transactions,  I  gave  the  fol- 
lowing detailed  description  of  its  nature  and 
properties :  — 

"  The  real  nature  of  the  capsule  of  the  lens 
has  not,  I  think,  been  sufficiently  attended  to; 
its  thickness,  strength,  and  elasticity,  have  cer- 
tainly been  noticed,  but  have  not  attracted  that 
attention  which  a  fact  so  interesting,  both  in  a 
physiological  and  pathological  point  of  view, 
deserves.  That  its  structure  is  cartilaginous,  I 
should  conclude,^rs/,  from  its  elasticity,  which 
causes  it  to  assume  a  peculiar  appearance  when 
the  lens  has  been  removed,  not  falling  loose 
into  folds  as  other  membranes,  but  coiled  in 
different  directions ;  or  if  the  lens  be  removed 
by  opening  the  capsule  behind,  and  with- 
drawing it  through  the  vitreous  humour,  allow- 
ing the  water  in  which  the  part  is  immersed  to 
replace  the  lens,  the  capsule  preserves  in  a 
great  degree  its  original  form,  especially  in  the 
eye  of  the  fish ;  secondly,  from  the  density  and 
firmness  of  its  texture,  which  may  be  ascer- 
tained by  attempting  to  wound  it  by  a  cataract 
needle,  by  cutting  it  upon  a  solid  body,  or 
compressing  it  between  the  teeth;  thirdly,  from 
its  permanent  transparency,  which  it  does  not 
lose  except  on  the  application  of  very  strong 
acid  or  boiling  water,  and  then  only  in  a  slight 
degree ;  maceration  in  water  for  some  months, 
or  immersion  in  spirit  of  strength  sufficient  to 
preserve  anatomical  preparations,  having  little 
or  no  effect  upon  it.  If  the  lens  be  removed 
from  the  eye  of  a  fish  dressed  for  the  table,  the 
capsule  may  be  raised  by  the  point  of  a  pin, 
and  be  still  found  almost  perfectly  transparent. 
This  combination  of  density  and  transparency 
gives  the  capsule  a  peculiar  sparkling  appear- 
ance in  water,  in  consequence  of  the  reflection 
of  light  from  its  surface,  resembling  a  portion 
of  thin  glass  which  had  assumed  an  irregular 
form  while  soft;  this  sparkling  I  consider  very 
characteristic  of  this  structure.  The  properties 
just  enumerated  appear  to  me  to  distinguish  it 
from  every  other  texture  but  cartilage ;  still, 
however,  it  may  be  said  that  cartilage  is  not 
transparent,  but  even  the  cartilage  of  the  joints 
is  semi-transparent,  and,  if  divided  into  very 
thin  portions,  is  sufficiently  pellucid  to  permit 
the  perception  of  dark  objects  placed  behind 
it,  and  we  obtain  it  almost  perfectly  transparent 
where  it  gives  form  to  the  globe  of  the  eye,  as 
in  the  sclerotic  of  birds  and  fishes.  If  the  soft 
consistence,  almost  approaching  to  fluidity,  of 
the  external  part  of  the  lens,  be  considered,  the 
necessity  of  a  capsule  capable  itself  of  pre- 
serving a  determinate  form  is  obvious.  If  the 
lens  were  enclosed  in  a  capsule  such  as  that 
which  envelopes  the  vitreous  humour,  its  sur- 
face could  not  be  expected  to  present  the  ne- 
cessary regular  and  permanent  curvature ;  nor 
could  we  expect  that  if  the  form  of  the  lens 
were  changed,  it  could  be  restored  without  this 
provision  of  an  elastic  capsule." 

The  capsule  is  liable  to  become  opaque  and 
constitute  cataract,  as  the  body  of  the  lens  is. 
These  capsular  cataracts  are  easily  distinguished 


200 


EYE. 


from  the  lenticular.  They  never  present  the 
stellated  appearance  frequently  observed  when 
the  texture  of  the  opaque  lens  opens  in  the  cap- 
sule as  it  does  when  macerated  in  water,  nor  the 
uniform  horny  or  the  milky  blue  appearance  of 
common  lenticular  cataract.  The  opacity  in 
capsular  cataract  exists  in  the  shape  of  irregular 
dots  or  patches,  of  an  opaque  paper-white  ap- 
pearance, and  when  touched  with  the  needle  are 
found  hard  and  elastic,  like  indurated  cartilage, 
the  spaces  between  the  specks  of  opacity  fre- 
quently remaining  perfectly  transparent. 

It  appears  to  be  generally  assumed  by  writers 
on  anatomy  that  a  watery  fluid  is  interposed 
between  the  body  of  the  lens  and  its  capsule, 
from  an  incidental  observation  of  Morgagni 
when  discussing  the  difference  in  density  be- 
tween the  surface  and  centre  of  the  lens;  hence 
it  has  been  called  the  aqua  Morgagni.  The 
observation  of  this  celebrated  anatomist,  in  his 
Adversaria  Anatomica,  which  has  led  to  the 
universal  adoption  of  this  notion,  is,  however, 
merely  that  upon  opening  the  capsule  he  had 
frequently  found  a  fluid  to  escape.  "  Deinde 
eadem  tunica  in  vitulis  etiam,  bobusque  sive 
recens,  sive  non  ita  recens  occisis  perforata, 
pluries  animadverti,  illico  humorem  quendam 
aqueum  prodire  :  quod  et  in  homine  observare 
visus  sum,  atque  adeo  credidi,  hujus  humoris 
secretione  prohibita,  crystallinum  siccum,  et 
opacum  fieri  fere  ut  in  extracto  exsiccatoque 
crvstallino  contingit."  He  does  not,  however, 
subsequently  dwell  upon  or  insist  upon  the 
point.  I  do  not  believe  that  any  such  fluid 
exists  in  a  natural  state,  but  that  its  accumula- 
tion is  a  consequence  of  loss  of  vitality;  the 
water  combined  with  the  solid  parts  of  the  lens 
escaping  to  the  surface  and  being  detained  by 
the  capsule,  as  occurs  in  the  pericardium  and 
other  parts  of  the  body.  In  the  eyes  of  sheep 
and  oxen,  when  examined  a  few  hours  after 
death,  not  a  trace  of  any  such  fluid  can  be 
detected,  but  after  about  twenty-four  hours  it 
is  found  in  considerable  quantity.  In  the 
human  eye  a  fluid  sometimes  accumulates  in 
the  capsule,  constituting  a  particular  form  of 
cataract,  which  presses  against  the  iris,  and 
almost  touches  the  cornea ;  but  such  eyes  are, 
I  believe,  always  unsound.  From  this  erro- 
neous notion  of  an  interposed  fluid  between 
the  lens  and  its  capsule  has  arisen  the  adop- 
tion of  an  unsustained  and  improbable  conclu- 
sion, that  the  lens  has  no  vital  connexion  with 
its  capsule,  and  consequently  must  be  produced 
and  preserved  by  some  process  analogous  to 
secretion.  Respecting  this  matter  I  have  ob- 
served, in  the  paper  above  alluded  to,  "  The 
lens  has  been  considered  by  some  as  having  no 
connexion  with  its  capsule,  and  consequently 
that  its  formation  and  growth  is  accomplished 
without  the  assistance  of  vessels;  such  a  notion 
is  so  completely  at  variance  with  the  known 
laws  of  the  animal  economy,  that  we  are  justi- 
fied in  rejecting  it,  unless  supported  by  un- 
questionable proof.  The  only  reasons  which 
have  been  advanced  in  support  of  this  conclu- 
sion are,  the  failure  of  attempts  to  inject  its 
vessels,  and  the  ease  with  which  it  may  be 
separated  from  its  capsule  when  that  mem- 


brane is  opened.  These  reasons  are  far  from 
being  satisfactory;  it  does  not  necessarily 
follow  that  parts  do  not  contain  vessels,  be- 
cause vve  cannot  inject  them ;  we  frequently 
fail  when  theie  can  be  no  doubt  of  their  exist- 
ence, especially  where  they  do  not  carry  red 
blood.  I  have  not  myself  succeeded  in  in- 
jecting the  vessels  of  the  lens,  but  I  have  not 
repeated  the  trial  so  often  as  to  make  me 
despair  of  accomplishing  it,  more  especially 
as  Albinus,  an  anatomist  whose  accuracy  is 
universally  acknowledged,  asserts,  that  after  a 
successful  injection  of  the  capsule  of  the  lens, 
he  could  see  a  vessel  passing  into  the  centre  of 
the  lens  itself.  Lobe,  who  was  his  pupil, 
bears  testimony  to  this.  The  assertion  that 
the  lens  is  not  connected  with  its  capsule,  I 
think  I  can  show  to  be  incorrect;  it  has  been 
made  from  want  of  care  in  pursuing  the  inves- 
tigation, and  from  a  notion  that  a  fluid  exists 
throughout  between  the  lens  and  its  capsule. 
When  the  capsule  is  opened,  its  elasticity 
causes  it  to  separate  from  the  lens ;  especially 
if  the  eye  be  examined  some  days  after  death, 
or  has  been  kept  in  water,  as  then  the  lens 
swells,  and  often  even  bursts  the  capsule  and 
protrudes  through  the  opening,  by  which  the 
connexion  is  destroyed.  I  have  however  satis- 
fied myself  that  the  lens  is  connected  with  its 
capsule  (and  that  connexion  by  no  means 
slight)  by  the  following  method.  I  remove 
the  cornea  and  iris  from  an  eye,  within  a  few 
hours  after  death,  and  place  it  in  water,  then 
with  a  pair  of  sharp-pointed  scissors  I  divide 
the  capsule  all  round  at  the  circumference  of 
the  lens,  taking  care  that  the  division  is  made 
behind  the  anterior  convexity,  so  that  the  lens 
cannot  be  retained  by  any  portion  of  the  cap- 
sule supporting  it  in  front.  I  next  invert  the 
eye,  holding  it  by  the  optic  nerve,  when  I  find 
that  the  lens  cannot  be  displaced  by  agitation, 
if  the  eye  be  sufficiently  fresh.  In  the  eye  of 
a  young  man  about  six  hours  dead,  I  found 
that,  on  pushing  a  cataract  needle  into  the  lens, 
after  the  anterior  part  of  the  capsule  had  been 
removed,  I  could  raise  the  eye  from  the  bottom 
of  the  vessel,  and  even  half  way  out  of  the 
water,  by  the  connexion  between  the  lens  and 
its  capsule.  It  afterwards  required  consider- 
able force  to  separate  them,  by  passing  the 
needle  beneath  the  lens,  and  raising  it  from  its 
situation.  I  believe  those  who  have  been  in 
the  habit  of  performing  the  operation  of  ex- 
traction, have  occasionally  encountered  consi- 
derable difficulty  in  detaching  the  lens  from 
its  situation  after  the  capsule  had  been  freely 
opened,  this  difficulty  I  consider  fairly  refer- 
able to  the  natural  connexion  just  noticed." 
When  the  lens  enclosed  in  its  capsule  is  de- 
tached from  the  hyaloid  membrane,  the  con- 
nexion between  it  and  the  capsule  is  destroyed 
by  the  handling,  and,  in  consequence,  it  moves 
freely  within  that  covering,  affording  to  those 
who  believe  that  there  is  no  union  between  the 
two  surfaces  fallacious  evidence  in  support  of 
that  opinion,  which,  if  not  sustained  by  better 
proof,  should  be  abandoned.  Dr.  Young  in- 
sists upon  the  existence  of  the  natural  con- 
nexion by  vessels  and  even  by  nerves  between 


EYE, 


the  lens  and  its  capsule ;  he  says,  "  The  cap- 
sule adheres  to  the  ciliary  substance,  and  the 
lens  to  the  capsule,  principally  in  two  or  three 
points ;  but  I  confess  I  have  not  been  able  to 
observe  that  these  points  are  exactly  opposite 
to  the  trunks  of  nerves;  so  that  probably  the 
adhesion  is  chiefly  caused  by  those  vessels 
which  are  sometimes  seen  passing  to  the  cap- 
sule in  injected  eyes.    We  may,  however,  dis- 
cover ramifications  from  some  of  these  points 
upon  and  within  the  substance  of  the  lens, 
generally  following  a  direction  near  to  that  of 
the  fibres,  and  sometimes  proceeding  from  a 
point  opposite  to  one  of  the  radiating  lines  of 
the  same  surface.    But  the  principal  vessels  of 
the  lens  appear  to  be  derived  from  the  central 
artery,  by  two  or  three  branches  at  some  little 
distance  from  the  posterior  vortex,  which  I 
conceive  to  be  the  cause  of  the  frequent  adhe- 
sion of  a  portion  of  a  cataract  to  the  capsule 
about  this  point ;  they  follow  nearly  the  course 
of  the  radiations  and  then  of  the  fibres ;  but 
there  is  often  a  superficial  subdivision  of  one 
of  the  radii  at  the  spot  where  one  of  them 
enters."    The  great  size  of  the  vessels  distri- 
buted on  the  back  of  the  capsule  in  the  foetus 
strengthens  the  conclusion  that  the  lens  is  fur- 
nished with  vessels  as  the  rest  of  the  body. 
When  the  eye  of  a  foetus  of  seven  or  eight 
months  is  finely  injected,  a  branch  from  the 
central  artery  of  the  retina  is  filled  and  may  be 
traced  through  the  centre  of  the  vitreous  hu- 
mour to  the  back  of  the  capsule,  where  it 
ramifies  in  a  remarkably  beautiful  manner, 
assuming,  according  to  Sommerring,  a  stellated 
or  radiating  arrangement.    Zinn  declares  that 
he  found  branches  from  this  vessel  penetrating 
the  lens :  "  Optime  autem  placet  observatio 
arteriolar  lentis,  in  oculo  infantis,  cujus  vasa 
cera  optime  erant  repleta,  summa  voluptate 
mihi  visas,  quam  prope  marginem  ad  convexi- 
tatem  posteriorem  diktam,   duobus  ramulis 
perforata  capsula  in  ipsam  substantiam  lentis 
profunde   se   immergentem    cortissime  con- 
spexi."     He   also  quotes  the  authority  of 
Ruysch,  Moeller,  Albinus,  and  Winslow,  as 
favouring  the  same  view.    Against  such  au- 
thority I  find  that  of  the  French  systematic 
writer  Bichat  advanced ;  but  on  such  a  point 
his  opinion  is  of  little  value.    Annexed  is 
Zinn's  representa- 
Fig.  125.  tion  of  the  distribu- 

tion of  the  branch 
of  the  central  artery 
on  the  back  of 
the  capsule,  from 
a  preparation  in 
Lieberkiihn's  mu- 
seum. Similar  fi- 
gures have  been 
given  by  Albinus, 
Sommerring,  and 
Sir  Charles  Bell. 
Of  the  aqueous  humour. — In  the  preliminary 
observations  at  the  commencement  of  this 
article,  I  stated  that  a  cavity  or  space  filled 
with  water  exists  between  the  cornea  and  crys- 
talline lens,  in  which  space  the  iris  is  extended, 
with  its  aperture  or  pupil,  to  moderate  the 


quantity  of  light,  and  interrupt  the  passage  of 
the  extreme  rays.    It  is  bounded  anteriorly  by 
the  concave  inner  surface  of  the  cornea,  and 
posteriorly  by  the  crystalline  lens  and  other 
parts,    and  is  necessarily  divided  into  two 
spaces  or  chambers  by  the  iris.    That  in  front 
of  the  iris,  called   the  anterior  chamber,  is 
bounded  by  the  concave  inner  surface  of  the 
cornea  anteriorly,  and  by  the  flat  surface  of  the 
iris  posteriorly,  which,  I  have  already  stated, 
is  a  plane,  not  a  convex  surface,  as  represented 
in  the  plates  of  Zinn  and  others.    The  size  of 
this  space  is  necessarily  small,  and  varies  in 
different  individuals  according  to  the  convexity 
of  the  cornea,  which  also  frequently  varies. 
It  is  always,  however,  sufficiently  large  to  allow 
the  surgeon  to  introduce  a  needle  to  break  up 
a  cataract  without  wounding  the  iris  or  cornea. 
The  posterior  chamber  is  bounded  in  front  by 
the  back  of  the  iris,  and  behind  by  the  crys- 
talline lens ;  with  that  portion  of  the  hyaloid 
membrane  of  the  vitreous  humour,  which  is 
between  the  anterior  termination  of  the  ciliary 
processes  of  the  choroid  and  the  circumference 
of  the  lens.    The  circumference  of  the  pos- 
terior chamber  is  bounded  by  the  anterior  ex- 
tremities of  the  ciliary  processes  of  the  choroid, 
as  they  extend  from  the  vitreous  humour  to  the 
back  of  the  iris.    It  does  not  appear  to  be 
generally  admitted  or  well  understood  that  any 
part  of  the  hyaloid  membrane  of  the  vitreous 
humour  enters  into  the  composition  of  the 
posterior    chamber    of    the     aqueous  hu- 
mour, notwithstanding  the  decisive  opinion 
and  accurate  representation  of  the  celebrated 
Sommerring,  in  which  I  entirely  concur,  as  I 
have  stated  above  in  describing  the  vitreous 
humour. 

The  size  of  the  posterior  chamber  has  been 
the  subject  of  much  discussion  and  contro- 
versy, and  various  attempts  have  been  made 
by  freezing  the  eye  and  other  means  to  deter- 
mine the  matter.  Petit,  after  a  careful  inves- 
tigation, considered  that  the  distance  between 
the  lens  and  iris  was  less  than  a  quarter  or  half 
a  line,  in  which  Haller  appears  to  concur. 
Winslow,  in  the  Memoirs  of  the  French  Aca- 
demy for  1721,  insists  that  the  iris  is  in  contact 
with  the  lens.  Lieutaud,  in  his  Essais  Ana- 
tomiques,  is  equally  positive  on  this  point, 
and  even  denies  altogether  the  existence  of  a 
posterior  chamber.  The  question  is  not  an 
indifferent  one,  inasmuch  as  it  involves  impor- 
tant considerations  as  to  operations  for  cataract 
and  inflammations  of  the  iris.  Modern  ana- 
tomists appear,  generally,  to  consider  the  dis- 
tance between  the  lens  and  iris  to  be  greater 
than  it  really  is.  Although  I  cannot  agree 
with  Winslow  and  Lieutaud  that  the  margin 
of  the  pupil  is  always  in  contact  with  the  lens, 
I  believe  it  frequently  is  so,  especially  in  the 
earlier  periods  of  life,  when  the  curvatures  of 
the  lens  are  considerable.  In  iritis  adhesions 
generally  take  place  between  the  margin  of  the 
pupil  and  the  capsule  of  the  lens,  a  conse- 
quence not  easily  accounted  for,  if  the  parts 
be  not  iu  contact.  In  old  age  the  lens  be- 
comes much  flattened,  and  therefore  retreats 
from  the  pupil,  to  such  a  degree  that  the  sha- 


202 


EYE. 


dow  of  the  iris  may  often  be  seen  in  aerescentic 
form  on  a  cataract ;  and  in  such  persons,  whe- 
ther from  this  cause  or  from  the  inflammation 
not  being  of  the  adhesive  character,  blindness 
is  more  frequently  attended  with  dilated  pupil. 
In  breaking  up  cataracts  through  the  cornea, 
I  have  repeatedly  satisfied  myself  of  the  con- 
tact or  close  vicinity  of  the  two  surfaces  by 
placing  the  needle  between  them.  The  an- 
nexed outline  section,  from  the  work  of  Sbm- 
merring,  shews  how 
small  he  considered  the 
space  between  the  iris 
and  lens,  and  displays 
accurately  how  the 
posterior  chamber  is 
formed  by  the  iris  an- 
teriorly, the  lens  pos- 
teriorly, and  the  cili- 
ary processes  at  the 
circumference,  with  the 
small  circular  portion 
of  the  hyaloid  mem- 
brane of  the  vitreous 
humour  between  the 
ciiliary  processes  of 
the  choroid  and  the 
circumference  of  the 
lens. 

It  appears  to  me  unaccountable  why  sur- 
geons, with  these  anatomical  facts  before  them, 
still  continue  to  introduce  the  needle  into  the 
posterior  chamber,  to  break  up  cataracts,  in- 
stead of  passing  it  through  the  cornea  into  the 
anterior  chamber,  where  ample  space  exists, 
and  a  full  view  is  obtained  of  all  the  steps  of 
the  operation.  In  doing  so  the  needle  is  thrust 
through  opaque  parts  among  delicate  structures, 
into  a  narrow  cavity,  where,  hidden  by  the  iris, 
it  can  be  used  with  little  certainty  of  correct 
application.  At  the  same  time,  instead  of 
penetrating  the  simple  structure  of  the  cornea, 
which  bears  injury  as  well  as  any  other  struc- 
ture of  the  body,  the  instrument  pervades  the 
fibrous  sclerotic,  a  structure  impatient  of  in- 
jury and  prone  to  inflammation,  punctures  the 
ciliary  ligament  at  the  imminent  risk  of  in- 
juring one  of  the  ciliary  nerves  or  even  wound- 
ing the  long  ciliary  artery,  and  finally  passes 
through  one  of  the  most  vascular  parts  in  the 
body,  the  corpus  ciliare.  The  practice  appears 
a  signal  instance  of  the  influence  of  education, 
habit,  and  authority  in  setting  improvement  at 
defiance.  The  proofs  afforded  of  the  close 
vicinity  of  the  margin  of  the  pupil  to  the  cap- 
sule of  the  lens,  should  remind  the  surgeon 
that  one  of  the  greatest  dangers  to  be  ap- 
prehended in  iritis  is  the  adhesion  of  these  two 
parts,  and  that  one  of  the  first  steps  in  the 
treatment  should  be  to  separate  them  by  the 
application  of  belladonna,  which,  by  its  pecu- 
liar influence  on  the  pupil,  dilates  that  aper- 
ture, and,  consequently,  brings  its  margin 
more  opposite  the  circumference  of  the  lens 
and  at  a  greater  distance  from  the  prominent 
central  portion. 

The  aqueous  humour,  although  constituting 
so  essential  a  part  of  the  optical  mechanism  of 
the  eye,  is  but  small  in  quantity ;  according  to 


Petit  not  more  than  four  or  five  grains.  Its 
specific  gravity  and  refractive  power  scarcely 
differ  from  that  of  water;  and  according  to 
Berzelius,  100  parts  contain  98.10  of  water, 
1.15  of  chloruret  of  soda  with  a  slight  trace 
of  alcoholic  extract,  0.75  of  extractive  matter 
soluble  in  water  only,  and  a  mere  trace  of 
albumen.  It  is  perfectly  transparent,  but  is 
said  to  be  milky  in  the  foetus. 

The  source  from  which  this  fluid  is  derived 
has  been  the  subject  of  controversy  in  con- 
sequence of  Nuck,  a  professor  of  anatomy  at 
Leyden,  having  asserted  that  he  had  discovered 
certain  ducts  through  which  it  was  transmitted, 
and  published  a  small  treatise  to  that  effect, 
which  ducts  were  proved  to  be  vesssels  by  a 
cotemporary  writer,  Chrouet,  in  which  deci- 
sion subsequent  authors  have  concurred.  In 
the  present  day  this  fluid  is  generally  believed 
to  be  secreted  by  a  membrane  lining  the  cavity, 
as  the  fluid  which  lubricates  the  serous  cavities 
is  secreted  by  their  lining  membranes.  Al- 
though this  is  in  all  probability  the  fact,  the 
circumstances  are  not  exactly  the  same  in  both 
cases.  In  the  serous  cavities,  merely  as  much 
fluid  as  moistens  the  surface  is  poured  out, 
while  in  the  chamber  of  the  aqueous  humour 
sufficient  to  distend  the  cavity  is  secreted.  In 
the  serous  cavities  the  membrane  from  which 
they  derive  their  name  can  be  demonstrated  ; 
in  the  chamber  of  aqueous  humour  this  can 
scarcely  be  accomplished.  I  have  resorted  to 
various  methods  to  enable  me  to  demonstrate 
the  existence  of  the  membrane  of  the  aqueous 
humour  on  the  back  of  the  elastic  cornea, 
such  as  maceration,  immersion  in  hot  water, 
soaking  in  alcohol,  and  treating  with  acids, 
alkalis,  and  various  salts,  but  without  effect. 
In  describing  the  structure  of  the  cornea,  I 
have  shewn  that  the  elastic  cornea  itself  can- 
not for  a  moment  be  considered  the  membrane 
in  question,  on  account  of  its  strength,  thick- 
ness, elasticity,  and  abrupt  termination ;  and 
I  do  not  think  that  the  demonstration  of  a 
serous  membrane  expanded  on  such  a  struc- 
ture as  transparent  cartilage  is  to  be  expected, 
inasmuch  as  the  demonstration  of  the  synovial 
membrane  on  the  cartilages  of  incrustation  in 
the  joints  is  attended  with  much  difficulty. 
The  pathological  fact  which  tends  most  to 
prove  the  existence  of  such  a  membrane  here, 
is,  that  in  iritis,  especially  that  of  a  syphilitic 
character,  the  aqueous  humour  appears  often 
very  muddy,  especially  in  the  inferior  half  of 
the  chamber;  this,  however,  in  the  latter  stages 
may  be  found  to  arise  from  a  delicate  speckled 
opacity  on  the  back  of  the  cornea,  which  re- 
mains permanently,  and  injures  vision  con- 
siderably. Analogy  also  favours  the  inference 
that  the  whole  cavity  of  the  chamber  must  be 
lined  by  serous  membrane,  inasmuch  as  all 
structures,  of  whatsoever  nature  they  may  be, 
in  the  serous  or  synovial  cavities,  are  so  covered 
or  lined.  This  provision  is  so  universal,  that 
if  such  various  structure,  as  the  elastic  cornea, 
iris,  capsule  of  the  lens,  ciliary  processes,  and 
hyaloid  membrane,  which  enter  into  the  con- 
struction of  the  chamber  of  aqueous  humour, 
be  exposed  to  the  contact  of  the  fluid  without 


EYE. 


203 


any  intervening  membrane,  it  constitutes  an 
unexpected  anomaly  in  the  animal  ceconomy. 
The  consequences  of  inflammation  greatly 
strengthen  the  conclusion  that  the  cavity  is 
lined  by  a  membrane  of  the  serous  character. 
The  slightest  injuries  or  even  small  ulcers  of 
the  cornea  are  frequently  accompanied  by  effu- 
sion of  purulent  matter  into  the  anterior 
chamber,  from  the  extension  of  the  inflam- 
mation into  that  cavity,  constituting  the  hy- 
popion  or  onyx  of  the  books ;  and  the  yellow 
masses  which  appear  on  the  iris  in  syphilitic 
iritis,  whether  they  are  abscesses,  or  as  they 
are  called,  globules  of  lymph,  are  effusions 
beneath  a  delicate  membrane,  as  vessels  may 
be  seen  with  a  magnifying  glass,  ramifying 
over  them.  In  iritis  the  rapidity  with  which 
adhesions  are  formed  between  the  margin  of 
the  pupil  and  the  capsule,  proves  that  these 
two  structures  are  covered  by  a  membrane  of 
this  nature.  In  addition  to  all  these  facts  the 
still  more  conclusive  one  is  to  be  adduced, 
namely,  that  the  membrane  can  without  diffi- 
culty be  demonstrated  on 
the  back  of  the  iris,  as 
I  have  stated  in  speaking 
of  that  part  of  the  organ, 
and  as  it  is  represented 
in  Jig.  127,  where  the 
fold  of  membrane  stained 
with  black  pigment  is  seen 
turned  down  from  that 
structure. 

In  the  preceding  pages  I  have  availed  my- 
self of  whatever  valuable  and  appropriate  facts 
in  comparative  anatomy  I  found  calculated  to 
illustrate  or  explain  the  structure  of  the  human 
eye.  There  are,  however,  two  organs  in  other 
animals  which  do  not  exist  even  in  the  most 
imperfect  or  rudimental  state  in  the  human 
subject — the  pecten  or  marsupium  nigrum  in 
birds,  and  the  choroid  gland  or  choroid  muscle 
in  fishes. 

Of  the  pecten. — This  organ  is  called  pecten 


from  its  folded  form  bearing  some  resemblance 
to  a  comb,  and  marsupium  nigrum  from  its 
resemblance  in  the  eye  of  the  ostrich  to  a  black 
purse,  according  to  the  anatomists  of  the 
French  Academy,  who  compiled  the  collection 
of  memoirs  on  comparative  anatomy.  The 
organ  is  obviously  a  screen  projected  from 
the  bottom  of  the  eye  forward  toward  the  crys- 
talline lens,  and,  consequently,  received  into 
a  corresponding  notch  or  wedge-shaped  hollow 
in  the  vitreous  humour;  it  appears  to  be  of 
the  same  vascular  structure  as  the  choroid,  and 
is  deeply  stained  with  the  black  pigment, 
which  renders  it  perfectly  opaque  and  imper- 
vious to  light.  The  annexed  figure,  from  the 
work  of  D.  W.  Sommerring,  represents  it  in 
the  eye  of  the  golden  eagle. 

Fig.  128. 


Fig  127. 


It  is  composed  of  a  delicate  membrane,  highly 
vascular,  folded  exactly  like  the  plaits  of  a  fan, 
and  when  removed  with  sharp  scissors  from 
the  bottom  of  the  eye,  and  its  free  margin  cut 
along  the  edge  so  as  to  allow  the  folds  to  be 
pulled  open,  it  may  be  spread  out  into  a  strip 
of  continuous  riband-shaped  membrane,  as 
seen  in  Jig.  1 29,  from  a  paper  of  Sir  E. 
Home's  in  the  Philosophical  Transactions  for 
1822. 


Fig.  129. 


The  first  account  I  find  of  it  is  by  Petit  in 
the  Mem.  de  1'Acad.  Roy.  1735.  He  says  it 
is  a  trapezium  or  trapezoid,  five  lines  long  at 
the  base,  and  three  lines  and  a  half  deep,  com- 
posed of  parallel  fibres,  and  that  a  fine  trans- 
parent filament  runs  from  the  anterior  superior 
angle  to  the  capsule  of  the  crystalline  lens, 
not  easily  seen  on  account  of  its  transparency, 
and  that  sometimes  the  angle  itself  is  attached 
to  the  capsule  near  its  margin.  Haller,  in  his 
work  "  Sur  la  formation  du  coeur  dans  le 


HP 


poulet,"  describes  it  as  follows: — "  It  is  a 
black  membrane  folded  at  very  acute  angles,  as 
the  paper  of  a  fan,  upon  which  transparent 
vessels  are  expanded ;  it  generally  resembles 
the  ciliary  processes.  It  originates  from  the 
sclerotic  in  the  posterior  part  of  the  eye  by  a 
serrated  line,  pierces  the  choroid,  retina,  and 
vitreous  humour  to  attach  itself  to  the  side  of 
the  capsule  of  the  crystalline,  very  near  the 
corona  ciliaris.  The  posterior  extremity  is 
broad,  and  the  anterior  narrows  till  it  becomes 


204 


EYE. 


adherent  to  the  capsule  of  the  lens  by  an  inser- 
tion a  little  narrower.  This  insertion  appears 
to  be  effected  by  the  intervention  of  the  hyaloid 
membrane,  to  which  this  fan  is  attached.  I 
have  not  had  time  to  establish  this  con- 
nexion to  my  satisfaction,  and  I  still  entertain 
doubts  respecting  it.  I  have  seen  a  red  artery 
accompany  this  feather-like  production  and  run 
to  the  crystalline.  It  would  be  very  convenient 
for  physiology  that  this  folded  membrane 
should  prove  muscular  ;  we  should  then  have 
the  organ  sought  after,  which  would  retract  the 
crystalline  to  the  bottom  of  the  eye."  In  the 
Elementa  Physiologic,  t.  v.  p.  390,  he  says  it 
originates  from  the  entrance  of  the  optic  nerve, 
but  that  you  may  remove  the  retina  and  leave 
the  pecten.  He  says  again,  "  it  advances  for- 
ward to  the  posteiior  part  of  the  capsule,  to 
which  it  sometimes  adheres  by  a  thread,  and 
sometimes  the  lens  is  merely  drawn  toward  it." 
An  artery  and  vein  is  supplied  to  each  fold, 
and  perhaps  to  the  capsule  of  the  lens.  In 
the  Opera  Minora  he  says  that  there  are  two 
red  vessels  to  each  fold  in  the  kite,  and  no  cord 
runs  to  the  lens ;  that  in  the  heron  a  branch  of 
artery  runs  to  each  fold,  and  it  adheres  so 
closely  to  the  lens  that  it  cannot  be  ascertained 
whether  a  red  vessel  runs  from  it  to  the  lens 
or  not ;  that  in  the  duck  it  is  contracted  toward 
the  lens,  and  adheres  to  it  by  a  thread  contain- 
ing a  red  vessel.  He  also  says  that  in  the 
wild  duck  it  arises  from  the  margin  of  the 
linea  alba,  which  terminates  the  entrance  of 
the  optic  nerve,  contains  numerous  vessels, 
and  adheres  to  the  lens ;  and  in  the  pie  it  is 
large  and  adheres  to  the  lens,  so  as  to  pull  it. 
D.  W.  Sbmmerring  says,  that  in  the  pecten 
of  the  golden  eagle,  of  which  Jig.  128  is 
a  representation,  there  are  fourteen  folds  like 
ciliary  processes,  and  that  it  adheres  by  a 
transparent  filament  to  the  capsule  of  the  lens ; 
that  in  the  great  horned  owl  it  is  short  and 
thick,  with  eight  folds,  and  adhering  to  the  lens 
by  an  hyaloid  filament,  although  at  a  great 
distance  from  it;  and  that  in  the  macaw  it  is 
longer  than  broad,  has  seven  folds,  and  adheres 
to  the  lens.  In  the  ostrich  he  says  it  is  shaped 
like  a  patella  at  its  base,  which  is  white,  oval, 
and  thick;  eight  lines  long  and  five  broad, 
distinctly  separate  from  the  choroid,  above 
which  it  rises,  the  retina  being  interposed. 
From  the  longer  diameter  of  this  patella  (or 
base)  a  white  plane  or  lamina  projects  even  up 
to  the  lens,  and  sends  out  on  each  side  seven 
small  plaits,  the  lower  ones  partly  double,  the 
upper  ones  simple,  black,  and  delicate.  This 
conical  body,  something  like  a  black  purse, 
tapers  toward  the  lens,  and  by  its  apex  is 
attached  to  the  capsule  by  a  short  semi-pellucid 
ligament.  The  white  substance  of  the  base 
and  partition  of  the  pecten  should  not  be  con- 
founded with  the  medullary  part  of  the  optic 
nerve,  which,  emerging  on  all  sides  from  be- 
neath the  base,  expands  into  a  great,  ample, 
and  tender  retina,  terminating  behind  the 
ciliary  processes  with  a  defined  margin.  Cuvier, 
in  his  Lectures  on  Comparative  Anatomy,  says, 
"  It  appears  of  the  same  nature  as  the  choroid, 
although  it  has  no  connexion  with  it ;  it  is  like- 


wise very  delicate,  very  vascular,  and  imbued 
with  black  pigment.  Its  vessels  are  derived 
from  a  particular  branch  of  the  ophthalmic 
artery,  different  from  two  which  belong  to  the 
choroid ;  they  descend  on  the  folds  of  the 
black  membrane  and  form  ramifications  there 
of  great  beauty  when  injected.  This  mem- 
brane penetrates  directly  into  the  vitreous 
humour,  as  if  a  wedge  had  been  driven  into 
it ;  it  is  in  a  vertical  plane  directed  obliquely 
forward.  The  angle  nearest  the  cornea  in  those 
species  in  which  it  is  very  broad,  and  all  its 
anterior  margin  in  those  in  which  it  is  narrow, 
comes  nearly  to  the  inferior  boundary  of  the 
capsule  of  the  crystalline.  In  some  species  it 
approaches  so  near  that  it  is  difficult  to  say 
whether  or  not  it  is  attached  to  it ;  such  is  the 
case  in  the  swan,  the  heron,  the  turkey,  &c. 
according  to  Petit ;  but  there  are  other  birds 
in  which  it  remains  at  some  distance,  and  in 
which  it  does  not  appear  to  attach  itself  except 
to  some  of  the  numerous  plates  which  divide 
the  vitreous  humour  into  cells.  In  the  swan, 
heron,  and  turkey,  this  membrane  is  broader 
in  the  direction  parallel  to  the  produced  extre- 
mity of  the  optic  nerve  than  in  the  contrary 
direction.  In  the  ostrich,  cassowary,  and  owl 
the  reverse  is  observed.  It  is  folded  like  a 
sleeve  in  a  direction  perpendicular  to  the  caudal 
termination  of  the  optic  nerve.  The  folds  are 
rounded  in  most  species ;  in  the  ostrich  and 
cassowary  they  are  compressed  and  sharp,  and 
so  high  perpendicular  to  the  plane  of  the 
membrane  that  at  first  sight  it  resembles  a 
black  purse.  The  folds  vary  in  number,  there 
being  sixteen  in  the  swan,  ten  or  twelve  in  the 
duck  and  vulture,  fifteen  in  the  ostrich,  and 
seven  in  the  grand  duke  or  great  horned  owl. 

The  purpose  for  which  the  pecten  exists  in 
the  eyes  of  birds  does  not  appear  to  be  fully 
ascertained.  Petit  says,  "  when  a  bird  views 
an  object  with  both  eyes,  the  rays  enter  oblique- 
ly in  consequence  of  the  situation  of  the  cornea 
and  crystalline  lens,  and  proceed  to  the  bottom 
of  the  eye ;  but  as  they  enter  in  lines  parallel 
to  the  membrane,  they  do  not  encounter  it. 
The  rays  which  enter  the  eye  in  lines  perpen- 
dicular to  the  plane  of  the  cornea  encounter 
this  membrane,  and  are  absorbed  by  it  as  well 
as  those  which  come  from  the  posterior  side ; 
the  subject  is,  however,  a  difficult  one."  Haller 
supposed  that  it  was  merely  destined  to  afford 
a  medium  through  which  vessels  might  pass  to 
carry  blood  to  the  crystalline.  Cuvier  says, 
"  It  is  difficult  to  assign  the  real  use  of  this 
membrane.  Its  position  should  cause  part  of 
the  rays  which  come  from  objects  at  the  side 
of  the  bird  to  fall  upon  it.  Petit  believed 
that  it  was  destined  to  absorb  these  rays  and 
prevent  their  disturbing  distinct  vision  of  objects 
placed  in  front.  Others  thought,  and  the 
opinion  has  been  lately  reiterated  by  Home, 
that  it  possesses  muscular  power,  and  that  its 
use  is  to  approach  the  lens  to  the  retina  when 
the  bird  wishes  to  see  distant  objects.  Never- 
theless, muscular  fibre  cannot  be  detected  in 
it,  and  the  experiments  intended  to  prove  its 
muscularity  after  death  are  not  absolutely  con- 
clusive ;  moreover,  as  it  is  attached  to  the  side 


EYE. 


205 


of  the  crystalline,  it  could  move  it  only 
obliquely."  The  experiments  and  inferences 
contained  in  Sir  E.  Home's  paper  in  the  Phi- 
losophical Transactions  for  1796,  do  not  appear 
to  me  worthy  of  any  attention.  A  pecten  in 
an  imperfect  or  rudimentary  state  appears  to 
exist  in  fishes  and  reptiles,  and  has  been  noticed 
by  Haller,  W.  Sommerring,  and  Dr.  Knox. 
In  the  article  Aves  of  this  work  Mr.  Owen 
has  also  described  the  pecten,  and  to  that  arti- 
cle I  refer  the  reader  for  additional  information. 

Of  the  choroid  gland  or  choroid  muscle. — 
The  eyes  of  fishes  present  several  remarkable 
peculiarities,  to  be  accounted  for  perhaps  from 
their  occasional  residence  in  the  obscurity  of 
the  deep,  and  at  other  times  near  the  surface, 
exposed  to  the  full  blaze  of  sunshine;  they 
must  also  be  frequently  exposed  to  great  pres- 
sure at  considerable  depths.  The  sclerotic  is 
not  merely  a  fibrous  membrane,  but  is  strength- 
ened by  a  cartilaginous  cup,  and  sometimes 
even  by  one  composed  of  bone ;  the  cornea  is 
generally  flat  or  presenting  little  of  lenticular 
character;  the  crystalline  lens  is  spherical,  and 
so  dense  that  its  central  part  is  a  hard  solid ; 
and  the  choroid  presents  the  remarkable  pecu- 
liarity which  I  have  now  to  describe. 

On  cutting  through  the  cartilaginous  sclerotic, 
a  fluid  is  found  generally  interposed  between 
this  and  the  choroid;  at  least  it  is  so  in  the 
genus  gadus,  (cod,  haddock,  &c.)  The  external 
part  of  the  choroid  is  formed  by  a  most  beau- 
tiful membrane  of  a  brilliant  silver  aspect, 
scarcely  to  be  distinguished  from  that  metal 
when  rough  and  recently  cleaned.  On  tearing 
this  membrane  away,  the  vascular  choroid  is 
exposed,  and  a  red  horse-shoe-shaped  promi- 
nent mass,  encircling  the  entrance  of  the  optic 
nerve,  appears.  This  is  the  choroid  gland  or 
choroid  muscle.  The  veins  of  the  choroid, 
apparently  commencing  from  the  iris,  ascend 
in  tortuous  inosculating  branches,  of  enormous 
size  compared  with  the  dimensions  of  the  part, 
and  appear  to  terminate  by  entering  this  horse- 
shoe-shaped organ,  but  this  is  not  their  distri- 
bution, as  it  is  not  hollow.  The  area  enclosed 
by  the  organ  round  the  optic  nerve  does  not 
exhibit  the  same  extreme  vascularity.  On 
pulling  away  a  delicate  film  which  covers  the 
organ,  it  appears  composed  of  lamina:  or  plates 
divisible  into  fibres,  which  run  transversely 
from  within  outwards,  confined  into  a  compact 
body  by  the  delicate  film  just  spoken  of,  and 
a  concave  depression  in  the  structure  beneath. 
The  annexed  plate,  made  from  an  accurate 
drawing  of  a  careful  dissection,  represents  the 
general  form  and  vascularity  remarkably  well. 


Fig.  130. 


Haller,  speaking  of  the  choroid  in  fishes, 
says,  "  this  organ  is  a  fleshy  pulp,  composed  of 
short  columns  densely  consolidated,  resembling 
red  gelatine."  Cuvier  says,  "  its  colour  is  com- 
monly a  vivid  red,  its  substance  is  soft  and 
more  glandular  than  muscular ;  at  least  fibres 
cannot  be  distinguished  on  it,  although  the 
bloodvessels  form  more  deeply  coloured  pa- 
rallel lines  on  its  surface.    Its  form  is  com- 
monly that  of  a  small  cylinder  bent  like  a  ring 
round  the  nerve,  which  ring  is  not,  however, 
complete ;  a  segment  of  greater  or  less  length  is 
always  deficient.    Sometimes,  as  in  the  Perca 
lubrax,  it  is  composed  of  two  pieces,  one  on 
each  side  of  the  optic  nerve.    In  other  cases  it 
is  not  in  a  circle  but  an  irregular  curve,  as  in 
the  Salmon,  Tetradon  mola,  and  Cod ;  but  in 
the  carps  and  most  other  fishes  it  approaches  to 
to  a  circle.    Those  who  suppose  that  the  eye 
changes  its  figure  according  to  the  distance  of 
objects,  think  that  this  muscle  is  destined  to 
produce  this  effect  by  contracting  the  choroid  ; 
but  it  appears  to  me  that  the  numerous  vessels 
passing  out  of  it  should  rather  lead  to  its  being 
considered  a  gland  destined  to  secrete  some  of 
the  humours  of  the  eye.  These  vessels  are  white, 
fine,  very  tortuous,  and  appear  to  traverse  the 
tunica Ruyschiana;  they  are  well  seen  in  the  Te- 
tradon mola  and  Perca  labrax.  In  the  Cod  they 
are  very  large,  anastomose  together,  and  are 
covered  by  a  white  and  opaque  mucus.  This 
gland  does  not  exist  in  the  cartilaginous  fishes, 
as  the  Rays  and  Sharks,  in  which  it  approaches 
more  to  the  character  of  the  eye  in  the  Mam- 
malia, as  has  already  been  observed  in  speak- 
ing of  the  tapetum  and  ciliary  processes."  D. 
W.  Summering  says,  "  Around  the  insertion  of 
the  nerve  is  seen  a  peculiar  red,  thick,  soft 
body  of  a  horse-shoe  shape,  respecting  which 
it  is  doubted  whether  it  be  muscular,  glandular, 
or  merely  vascular.    It  is  undoubtedly  ex- 
tremely vascular,  and  contains  many  large, 
branching,    inosculating   vessels,   forming  a 
proper  membrane  gradually  becoming  thin, 
and  terminating  at  the  iris.     This  vascular 
membrane  constitutes  the  second  or  middle 
layer  of  the  choroid."   This  description  applies 
to  the  eye  of  the  Cod.    Sir  E.  Home,  in  a 
Croonian  lecture  published  in  the  Philoso- 
phical Transactions  for  1796,  says  that  Mr. 
Hunter  considered  the  organ  in  question  to 
be  muscular,  and  proceeds  to  state  that  "  this 
muscle  has  a  tendinous  centre  round  the  optic 
nerve,  at  which  part  it  is  attached  to  the  scle- 
rotic coat;  the  muscular  fibres  are  short,  and 
go  off  from  the  central  tendon  in  all  directions: 
the  shape  of  the  muscle  is  nearly  that  of  a 
horse-shoe;  anteriorly  it  is  attached  to  the 
choroid  coat,  and  by  means  of  that  to  the 
sclerotic.    Its  action  tends  evidently  to  bring 
the  retina  forwards ;  and  in  general  the  optic 
nerve  in  fishes  makes  a  bend  where  it  enters 
the  eye,  to  admit  of  this  motion  without  the 
nerve  being  stretched.    In  those  fishes  that 
have  the  sclerotic   coat  completely  covered 
with  bone,  the  whole  adjustment  to  great  dis- 
tances must  be  produced  by  the  action  of  the 
choroid  muscle;  but  in  the  others,  which  are 
by  far  the  greater  number,  this  effect  will  be 


206 


EYE. 


much  assisted  by  the  action  of  the  straight 
muscles  pulling  the  eye-ball  against  the  socket, 
and  compressing  the  posterior  part,  which,  as 
it  is  the  only  membranous  part  in  many  fishes, 
would  appear  to  be  formed  so  for  that  pur- 
pose" Although  it  must  be  admitted  that 
these  conclusions  of  Sir  E.  Home  are  derived 
from  insufficient  data,  and  are  probably  incor- 
rect in  many  particulars,  yet  it  is  not  very  im- 
probable that  the  part  in  question  may  be  mus- 
cular, and,  if  so,  may  be  instrumental  in  adapt- 
ing the  eye  to  distance  by  pushing  up  the 
retina  toward  the  lens.  The  organization  of 
the  part  is  certainly  not  merely  vascular,  as 
stated  by  Cuvier,  and  undoubtedly  bears  a 
stronger  resemblance  to  muscular  than  any 
other  structure ;  it  also  retains  the  peculiar 
colour  of  red  muscle  after  all  the  rest  of  the 
eye  has  been  blanched  by  continued  macera- 
tion in  water.  I  think,  however,  Sir  E.  Home 
goes  too  far  when  he  describes  a  central  tendon 
without  reservation. 

For  further  information  on  the  subject  of 
this  article,  see  Vision,  and  Vision,  Organ 
of. 

BIBLIOGRAPHY. — In  pursuit  of  information  re- 
specting the  anatomy  of  the  eye,  the  student  need 
scarcely  go  farther  back  than  Zinn's  work,  or  the 
article  on  the  same  subject  in  Haller's  Elementa 
Physiologic  The  older  anatomical  writers  were, 
generally  speaking,  uninformed  on  the  subject. 
Ruysch's  works  contain  some  observations  worthy 
of  attention  at  the  time  he  wrote,  but  now  scarcely 
worth  recording  ;  especially  as  he  was  a  vain  man, 
and  wrote  for  present  fame  and  character  rather 
than  truth.  In  Albinus's  Annotationes  Academical 
a  few  facts  are  recorded,  upon  the  accuracy  of 
which  the  student  may  place  reliance,  as  he  was 
an  anatomist.  Morgagni  also  added  to  the  existing 
information  of  the  period  at  which  he  wrote,  but 
has  left  little  more  than  notes  or  cursory  remarks. 
Petit's  papers  in  the  Memoires  de  1  Academie 
Royale  des  Sciences  contain  much  original  and 
valuable  matter.  In  this  earlier  period  the  con- 
tributions of  Nuck,  Hovius,  Briggs,  and  Leeuwen- 
hoek  should  not  be  overlooked.  Coteraporary  with 
or  immediately  following  Haller  and  Zinn,  Porter- 
field,  Le  Cat,  Lieutaud,  the  second  Monro,  Blu- 
menbach,  Sommerring,  and  many  others  made 
valuable  additions  to  our  information  on  this  subject. 
The  annexed  list  contains  the  titles  of  those  works 
which  I  have  consulted  ;  some  of  the  more  modern 
German  monographs  I  have  been  obliged  to  quote 
or  consult  from  those  who  copied  from  them, 
having  endeavoured  in  vain  to  procure  them  :  such 
are  those  of  Ddllenger,  Chelius,  Huschke,  Jacob- 
son,  Kicser,  Weber,  and  some  others. 

Nuck,  Lialographia  et  ductuum  aquosorum  ana- 
tome  nova,  Lugd.  Bat.  1695.  Warner  Chrouet, 
De  tribus  humoribus  oculi,  1691.  Hovius,  De  circu- 
lari  humorum  motu  in  oculis,  Ludg.  Bat.  1716. 
Briggs,  Ophthalmographia,  Lugd.  Bat.  1686. 
Leuwenhoek,  Arcana  naturae  detecta,  Delphis,  1695  ; 
or  in  the  Philosophical  Transactions,  or  in  the 
translation  of  his  select  works  by  Hoole,  Lond. 
1816.  Ruyschii  Thesaurus,  Amstel.  1729.  Al- 
binus,  Annotationes  academical.  Morgagni,  Ad- 
versaria anatomica,  Ludg.  Bat.  1723,  and  Epistola:, 
Venetiis,  1750.  Haller,  Elementa  physiologia; 
corporis  humani,  torn.  v.  Lausanne,  1763  ;  also 
in  Opera  minora,  and  Formation  du  cocur  dans  le 
poulet.  Zinn,  Descriptio  anatomica  oculi  humani, 
Gotting.  1780,  and  also  in  Commentarii  Societatis 
Rpgiie  Scientiarum  Gotlingenses,  t.  iv.  1754.  Petit, 
in  Memnires  de  l'Academie  Royale  des  Sciences, 
1723,  25,  26,  &c.     Winslow,   Mem.  de  i'Acad. 


1721.  Moeller,  Observationes  circa  retinam,  in 
Halleri  Disputationes  anatomica;  select,  t.  vii. 
Camper,  De  quibusdam  oculi  paitibus,  in  Halleri 
Disp.  anat.  Lobe,  De  oculo  humano,  in  same. 
Wintringham,  On  animal  structure,  London,  1740. 
Le  Cat,  Traite  des  Sens,  Rouen,  1740.  Bertrandi, 
Dissertatio  de  oculo,  in  Opere  anatomische  e 
cerusiche.  Porterfield,  On  the  eye,  Edinburgh,  1759. 
Lieutaud,  Essais  anatomiques,  Paris,  1766.  Dud- 
dell,  Treatise  on  the  diseases  of  the  horny  coat  in 
the  eye,  Lond.  1729.  Descemet,  An  sola  lens 
crystallina  cataractae  sedes,  Paris,  1758.  Demours, 
Lettre  a  M.  Petit,  Paris,  1767.  Brendel,  De  fabrica 
oculi  in  fcctibus  abortivis,  Got.  1752.  Blumenbach, 
De  oculis  leucoethiopum  et  iridis  motu,  Gott.  1786. 
Wachendorf,  Commercium  litterarium,  1744.  Fon- 
tana,  Traite  sur  le  venin  de  la  vipere,  Florence, 
1781.  Walther,  J.  G.  Epistola  anat.  ad  Wilhelm 
Hunter,  Berolin,  1758.  Soemmering,  Abbildungen  des 
menschlichen  Auges,  or  Icones  oculi  humani  ;  or 
translated  into  French  by  Demours.  Simmering,  also 
in  Commentarii  Soc.  Reg.  Gotting.  Monro,  On  the 
brain,  the  eye,  and  the  ear,  Edin.  1797.  Camparetti, 
Observationes  dioptrics;  et  anatomica;  de  coloribus, 
visu  et  oculo,  Patavii,  1798.  Sattig,  Lentis  crys- 
tallina; structura  fibrosa,  Halae,  1794.  Mauchart, 
De  cornea,  in  Haller's  Disputationes  chirurgica;, 
or  in  Reuss  Dissertationes  Tubingenses.  Dr. 
Young,  in  the  Philosophical  Tansactions,  1793  et 
seq.  Home,  in  several  papers  in  the  Philosophical 
Transactions,  see  Index.  Red,  De  structura  ner- 
vorum, Halae,  1796.  Rosenthal,  De  oculi  quibus- 
dam partibus,  1801.  Angely,  De  oculo  organisque 
lachrymalibus,  Erlang.  1803  ;  or,  again,  Schreger 
vergleichenden  Anatomie  des  Auges,  Leipzig,  1810. 
Baerens,  Systematis  lentis  crystallina  monographia, 
Tubings,  1819,  and  in  Radius  Scriptores  oph- 
thalmologic minores.  Clemens,  Tunica;  cornea;  et 
humoris  aquei  monographia,  Gott.  1816,  and  in 
Radius,  S.  O.  M.  Sacks,  Historia  duorum  leu- 
ccethiopum,  Solisbaci,  1812.  Maunoir,  Sur  l'or- 
ganisation  de  l'iris,  Paris,  1812.  Ribes,  in  Me- 
moires de  la  Societe  Med.  d'Emulation,  an  8ieme, 
Paris,  1817.  Chelius,  Ueber  die  durchsichtige 
Hornhaut  des  auges,  Carlsruhe,  1818.  Voit,  Oculi 
humani  anatomia  et  pathologia,  Norimbergae,  1810. 
Hegar,  De  oculi  partibus  quibusdam,  Gott.  1818. 
Cuvier,  Le<;ons  d'anat.  comp.  Bell's  Anatomy. 
Meckel's  Handbuch  d.  menschl.  anatomie,  or  the 
French  translation.  Sommering,  D.  W.  De  oculorum 
hominis  animaliumque  sectione  horizontale,  Gott. 

1818.  Knox,  Comparative  anatomy  of  the  eye. 
Trans.  Royal  Society  of  Edinburgh,  1823.  Cloquet, 
J.  Sur  la  membrane  pupillaire,  Paris,  1818. 
«/acofao»,SuppIementa  ad  ophthalmiatriam.Havnia;, 
1821.  Ddllenger,  Illustratio  ichnographica  oculi, 
Werceburg,  1817.  Weber,  De  motu  iridis,  Lipsia;, 
1828.  Jacob,  in  Philosophical  Transactions,  1819. 
Martegiani,  Novae  observationes  de  oculo  human., 
Napoli,  1812.  Sawrey,  An  account  of  a  newly- 
discovered  membrane  in  the  human  eye,  Lond. 
1807.  Husche,  Commentatio  de  pectinis  in  oculo 
avium  potestate,  Jense,  1827.  Schneider,  Das  ende 
der  nervenhaut  in  menslichen  auges,  Munchen, 
1827.  Kieser,  De  anamorphosi  oculi,  Gott.  1804. 
Jacob,  in  Medico-Chirurgical  Transactions,  vol.  xii. 
Lond.  1823.  F.  A.  ab  Ammon,  De  genesi  et  usu 
maculae  lutrae,  Vinariae,  1830.  Dieterich,  F.  C. 
Uber  die  verwundengen  des  linsensystems,  Tubing. 
1824.  Ddllenger,  Uber  das  Strahlenblaitchen  im 
menschlkhen  auges  in  Acta  Ph.  Med.  Acad.  Caesar- 
Leop.  Car.  nat.  cur.  t.  ix.  Horrebow,  M.  Tractatus 
de  oculo  humano,  Havniae,  1792.  Jacob  Imans, 
Dissertatio  inaug.  de  oculo,  Lugd.  Bat.  1820. 
Lieblien,  V.  Bemerkungen  uber  das  system  der 
krystalliense  bei  Saugthieren  und.  vogeln.  Wurz- 
burg,  1821.  Muller,  F.  Anatomische  und  physio- 
logische  darstellung  des  menschlichen  auges,  Wien. 

1819.  J.  Muller,  Zur  vergliechenden  physiologie 
des  gesichtssines  des  menschen  und  der  Thiere, 
Leipsig,  1826.  G.  R.  Treviranus,  Beilrage  zur 
anatomie  und  physiologic  der  Sinnesweikezcuge  des 


FACE. 


207 


Menschen  und  der  Thiere,  1  Heft.  Bremen,  1828. 
Wardrop's  Morbid  anatomy  of  the  eye.  Dalrymple's 
Anatomy  of  the  eye,  Lond.  1834.  Mackenzie,  On 
diseases  of  the  eye,  Lond.  1834.  Lloyd,  On  light 
and  vision,  Lond.  1831.  Biot,  Precis  elementaire 
d«  physique,  Paris,  1824.  Langenbeck,  B.  C.  R. 
De  retina,  Gott.  1836.  Berzelius,  Traitede  chimie, 
Paris,  1833.  Ammon,  Zeitschrift  fur  die  oph- 
thalmologic. Radius,  Scriptores  ophthalmologic! 
minores.  Reils,  Archiv.  fiir  die  physiologie. 
Meckel's  Archiv.  F.  Arnold,  Untersuchungen  iiber 
das  auge  des  menschen,  Heidelberg,  1832.  Giralde, 
Sur  ['organization  de  l'ceil,  Paris,  1836.  For  the 
latest  observations  on  the  retina,  see  Ehrenberg, 
Beobachtung  iiber  Structur  des  Seelenorgans,  Ber- 
lin, 1836. 

For  the  comparative  anatomy  of  the  eye,  which 
is  still  imperfect,  I  refer  the  student  to  the  paper 
of  Zinn  in  the  Gottingen  Commentaries,  as  above 
quoted  ;  Bidloo,  De  oculis  et  visu ;  the  article  on 
the  eye  in  Haller's  Elementa  Physiologiae ;  Cam- 
paretti's  observations;  Home's  papers  in  the  Philo- 
sophical Transactions ;  Knox's  Comparative  ana- 
tomy of  the  eye  ;  Cuvier's  Comparative  anatomy  ; 
J.  Muller,  Vergleichende  Physiologie  des  Gesicht- 
sinnes ;  and,  above  all,  to  D.  W.  Sbmmering's 
book.  For  perfect  systematic  treatises  on  the 
anatomy  of  the  eye,  the  student  is  referred  to 
Zinn's  well-known  and  highly  valuable  work, 
Arnold's  work  just  quoted,  and,  in  English, 
Mr.  Dalrymple's  treatise. 

(Arthur  Jacob.) 

FACE  (in  anatomy)  (Gr.  nzaawrtov ;  Lat. 
fades,  vultus,  os ;  Tr.fuce;  Germ.  Antlitz, 
Gesicht ;  Ital.  faccia ). — In  vertebrated  animals 
this  term  is  applied  to  denote  the  anterior  part 
of  the  head,  with  which  most  of  the  organs 
of  the  senses  are  connected  ;  while  the  cranium 
is  destined  to  contain  and  protect  the  encephalic 
organs,  the  face  is  the  seat  of  the  organs  of 
sight,  smell,  and  taste,  and  in  some  animals 
of  a  special  organ  of  touch.  The  relative 
sizes  of  cranium  and  face  depend,  therefore, 
in  a  great  measure  on  the  relative  development 
of  those  important  organs  which  belong  to 
each.  For  the  characters  of  the  face  in  the 
different  classes  of  animals,  we  refer  to  the 
articles  devoted  to  the  anatomy  of  them,  and 
to  the  article  Osseous  System. 

Face  (in  human  anatomy).  The  face  is 
situated  before  and  below  the  cranium,  which 
bounds  it  above  ;  on  the  sides,  it  is  limited  by 
the  zygomatic  arches,  behind  by  the  ears  and 
the  depression  which  corresponds  to  the  upper 
region  of  the  pharynx,  and  below  by  the  base 
of  the  lower  jaw  and  the  chin.  The  disposition 
pf  the  face  is  symmetrical ;  its  anterior  surface 
is  trapezoidal,  the  largest  side  being  above ; 
and  its  vertical  section  is  triangular.  It  pre- 
sents an  assemblage  of  organs  which  serve  dif- 
ferent purposes,  and  which  by  their  configura- 
tion and  proportions  constitute  what  are  called 
the  features;  individually  the  face  presents 
many  varieties,  not  only  in  the  foim  and  degree 
of  development  of  its  several  parts,  as  the  nose, 
mouth,  &c,  but  also  in  the  condition  of  its 
bones,  muscles,  skin,  and  adipose  tissue.  The 
varieties  of  form  presented  by  the  face  afford 
some  of  the  most  distinctive  characters  of  the 
different  races  of  mankind.  It  differs  also  ac- 
cording to  the  age  and  sex  of  the  individual ; 
in  the  infant,  the  peculiarities  depend  princi- 
pally upon  the  disposition  of  the  bones,  and  in 
particular  on  the  absence  of  the  teeth ;  but  the 


soft  parts  have  also  their  distinctions  at  this 
age,  for  while  the  fat  is  abundant,  the  muscles 
are  but  little  developed,  and  hence  the  slightly 
marked  features  and  the  plump  cheeks  of 
infancy. 

In  old  age,  again,  the  aspect  of  the  face  is 
the  reverse  of  this,  for  not  only  do  its  thinness 
and  the  predominance  of  the  muscles  throw 
out  the  features,  but  the  skin  is  covered  with 
folds  and  wrinkles,  from  its  own  relaxation 
and  the  absence  of  fat,  aided  perhaps  by  the 
action  of  the  muscles.  The  loss  of  the  teeth, 
moreover,  allows  the  lower  jaw  (when  the 
mouth  is  closed)  to  be  thrown  in  front  of  the 
upper,  and  thus  the  length  of  the  face  is  dimi- 
nished, and  a  peculiar  expression  is  imparted 
to  the  countenance. 

In  women,  (from  the  delicacy  of  the  features 
and  the  abundance  of  the  cellular  tissue,)  the 
face  preserves  the  roundness  of  form,  and 
something  of  the  characteristics  of  childhood. 

Bones  of  the  Face. — The  bones  of  the 
face  comprise  all  those  of  the  skull  which  do 
not  contribute  to  form  the  cavity  for  the  brain ; 
they  inclose,  either  by  themselves  or  in  con- 
junction with  the  adjacent  bones  of  the  cranium, 
1 .  the  organs  of  three  senses,  viz.  sight, 
smelling,  and  taste  ;  2.  the  organs  of  mastica- 
tion and  the  orifices  of  the  respiratory  and 
digestive  canals ;  3.  they  give  attachment  to 
most  of  the  muscles  of  expression. 

The  face  is  divided  into  the  upper  or  the 
fixed,  and  the  lower  or  the  moveable  jaw, 
both  of  which  are  provided  with  teeth.  The 
lower  jaw  is  a  single  and  symmetrical  bone ; 
the  upper  jaw,  though  formed  of  thirteen 
bones,  consists  principally  of  two,  viz.  the 
ossa  maxillaria  superiora,  to  which  the  others 
may  be  considered  as  additions,  being  attached 
to  them  immoveably,  and  forming  altogether 
one  large,  irregular,  and  symmetrical  piece, 
which  constitutes  the  upper  jaw. 

Of  the  fourteen  bones  which  contribute  to 
the  face,  two  only  are  single  or  median  ;  the 
others  are  double,  and  form  six  pairs,  viz. 
2  ossa  maxilla  superioris ;  2  ossa  paluti ; 
2  ossa  nasi ;  2  ossa  mala  ;  2  ossa  lachrymalia  ; 
2  ossa  turbinata  inferiora.  The  two  single 
bones  are,  the  vomer  and  the  os  maxilla  in- 
serioris. 

The  superior  maxillary  bones,  ( ossa  maxil- 
luria superiora ;  Germ,  die  Obern  Kinnbacken- 
beine  oder  Oberkiefer.)  These  bones,  situated 
in  the  middle  and  front  of  the  face,  are  of 
a  very  irregular  figure ;  they  are  united  below 
along  the  median  line,  and  form  together,  the 
greater  part  of  the  upper  jaw.  Each  has  four 
surfaces,  viz.  i.  a  facial  or  anterior;  2.  a 
posterior  or  zygomatic ;  3.  an  internal  or  naso- 
palatine; 4.  a  superior  or  orbitur.  The  borders 
are  three;  1.  an  anterior  or  naso-maxillary ; 
2.  a  posterior  or  pterygoid;  3.  an  inferior  or 
alveolar. 

The  facial  surface  presents  from  before 
backwards,  1.  the  fossa  myrtiformis,  a  depres- 
sion situated  above  the  incisor  teeth,  which 
gives  attachment  to  the  depressor  labii  superi- 
oris; 2.  the  canine  ridge,  which  corresponds  to 
the  socket  of  the  canine  tooth,  and  which  sepa- 
rates the  myrtifoim  from,  3.  the  canine  (or  the 


208 


FACE. 


infra-orbitar)  fossa,  which  gives  attachment  to 
the  levator  anguli  oris,  and  at  the  upper  part  of 
which  is  seen  the  infra-orbitar  foramen,  giving 
exit  to  the  vessels  and  nerves  of  the  same 
name  ;  4.  the  malar  ridge,  a  semicircular  crest 
which  descends  vertically  from  the  malar  pro- 
cess to  the  alveolar  border  of  the  bone,  and 
divides  its  facial  from  its  zygomatic  surface, 
which  is  prominent  behind,  where  it  forms  the 
maxillary  tuberosity,  most  conspicuous  before 
the  exit  of  the  last  molar  tooth,  which  in  the 
child  is  lodged  within  it.  On  this  surface  are 
several  small  holes,  (posterior  dental  fora- 
mina,) which  are  the  orifices  of  canals  for  the 
posterior  and  superior  dental  vessels  and 
nerves. 

From  the  upper  and  front  part  of  the  ante- 
rior surface  of  the  bone  a  long  vertical  process 
{the  nasal  process )  ascends  between  the  nasal 
and  lachrymal  bones  to  be  united  with  the 
frontal ;  its  external  surface  is  rough,  presenting 
small  irregular  holes,  which  transmit  vessels  to 
the  cancellous  interior  of  the  bone  and  to  the 
nose,  and  giving  attachment  to  the  levator  labii 
superiorisalsque  nasi  muscle.  The  internal  sur- 
face of  this  process  is  marked  with  some  minute 
grooves  and  holes  for  vessels,  and,  tracing  it 
from  below  upwards,  by  a  transverse  ridge  or 
crest  {the  inferior  turbinated  ridge )  for  the 
lower  spongy  bone ;  above  this  by  a  depres- 
sion corresponding  to  the  middle  meatus;  next 
by  a  crest  ( the  superior  turbinated  ridge ) 
for  the  upper  spongy  bone  of  the  ethmoid ; 
and  above  this  by  a  surface  which  receives 
and  completes  some  of  the  anterior  ethmoid 
cells.  The  nasal  process  has  three  borders: 
i.  an  anterior,  thin  and  inclined  from 
above  downwards  and  forwards;  above,  it  is 
cut  obliquely  from  the  internal  towards  the 
external  surface  of  the  bone,  and  below  in  the 
contrary  direction,  so  that  this  edge  of  the 
nasal  process  and  the  corresponding  border  of 
the  nasal  bone  with  which  it  is  united,  mutu- 
ally overlap  each  other.  2.  A  posterior  border, 
or  surface,  thick  and  divided  into  two  margins 
by  a  deep  vertical  groove  (the  lachrymo-nasal 
canal)  which  contributes  to  lodge  the  lachrymal 
sac  above,  and  the  nasal  duct  below.  The 
direction  of  the  lachrymo-nasal  canal  is  curved 
from  above  downwards  and  outwards  ;  so  that 
its  convexity  looks  forwards  and  inwards,  and 
its  concavity  in  the  contrary  direction.  The 
inner  margin  of  this  groove  is  thin,  and  is 
united  above  to  the  anterior  border  of  the  os 
unguis,  and  below  to  the  inferior  spongy  bone. 
The  outer  margin  is  bounded  and  gives  attach- 
ment to  the  tendon  and  to  some  of  the  fibres  of 
the  orbicularis  palpebrarum  ;  it  commonly  ter- 
minates below  in  a  little  tubercle  (the  lachrymal 
tubercle).  3.  The  upper  border  of  the  nasal 
process,  which  is  short,  thick,  and  irregular,  is 
articulated  with  the  internal  angular  process  of 
the  frontal  bone. 

The  orbitar  surface  of  the  bone  is  the  small- 
est; it  is  quadrilateral,  smooth,  and  slightly 
concave,  with  an  inclination  from  above  down- 
wards and  from  within  outwards  ;  it  forms  the 
greater  part  of  the  floor  of  the  orbit.  Along 
the  middle  of  its  posterior  half  runs,  in  a  direc- 
tion forwards  and  outwards,  the  infra-orbitar 


groove,  which  anteriorly  becomes  a  complete 
canal  {the  infra-orbitar  canal ),  and  finally 
divides  into  an  internal  or  larger  canal,  which 
terminates  at  the  infra-orbitar  hole  in  the 
canine  fossa,  and  into  an  external  or  small 
conduit,  which  runs  in  the  anterior  wall  of  the 
antrum,  and  conveys  the  superior  anterior  den- 
tal nerves  to  the  incisor  and  canine  teeth  ;  this 
outer  subdivision  of  the  canal  presents  several 
varieties  in  different  individuals.  The  orbitar 
surface  (or  plate)  has  four  borders:  1.  The 
posterior,  which,  free  and  notched  in  the  mid- 
dle by  the  commencement  of  the  infra-orbitar 
canal,  forms  with  the  orbitar  plate  of  the  sphe- 
noid and  palate  bones  the  inferior  orbitar  or 
the  spheno-maxillary  fissure.  2.  The  internal, 
which  articulates  from  behind  forwards  succes- 
sively with  the  palate,  the  ethmoid,  and  the 
lachrymal  bones.  3.  The  anterior,  short  and 
smooth,  separates  the  orbitar  from  the  facial 
surfaces  of  the  bone;  at  its  inner  extremity  is 
the  nasal  process  already  described.  4.  The 
external  is  united  to  the  malar  bone;  on  the 
outer  side  of  this  border  is  a  rough  triangular 
projecting  surface  (the  malar  process )  which 
receives  the  os  mala,  and  which  forms  an 
angle  of  union  between  the  anterior,  posterior, 
and  superior  surfaces  of  the  upper  maxillary 
bone. 

The  internal  or  naso-palatine  surface  is  di- 
vided along  the  anterior  three-fourths  into  two 
unequal  parts  by  an  horizontal  plate  of  bone 
{the  palatine  process) :  above  this  is  the  nasal 
portion  forming  the  upper  three-fourths  of 
this  surface,  and  below  it,  is  the  palatine 
part  which  forms  the  remaining  fourth.  The 
palatine  process  forms  the  anterior  three- 
fourths  of  the  floor  of  the  nose,  and  roof  of  the 
mouth;  it  presents  a  smooth  upper  surface, 
concave  transversely,  and  nearly  flat  in  the  op- 
posite direction  :  it  is  broad  behind  and  narrow 
in  front,  where  there  is  placed  the  orifice  of  the 
anterior  palatine  canal,  which  takes  a  direction 
downwards,  forwards,  and  inwards,  unites  with 
the  corresponding  canal  in  the  opposite  bone 
at  the  median  plane,  and  forms  a  common 
canal  {the  canulis  incisivus ),  which  opens  below 
by  a  hole  {the  foramen  incisivum )  on  the  roof 
of  the  mouth,  immediately  behind  the  middle 
incisor  teeth.  The  anterior  palatine  canals  and 
the  incisive  canal,  which  are  often  included  to- 
gether under  a  common  name,  form  a  tube  re- 
sembling the  letter  Y,  being  bifid  above  and 
single  below.  The  inferior  surface  of  the  pa- 
latine process  is  rough  and  concave,  and  forms 
the  anterior  and  larger  part  of  the  roof  of  the 
mouth  ;  its  internal  border  is  long  and  rough, 
thick  in  front,  narrow  behind,  and  united  with 
the  corresponding  border  of  the  opposite  bone 
forms  the  maxillary  suture :  this  border  is  sur- 
mounted by  a  half-furrow  which,  with  that  of  its 
fellow  bone,  forms  a  groove  for  the  reception  of 
a  part  of  the  vomer.  The  posterior  border  is  short 
and  cut  obliquely  at  the  expense  of  the  upper 
surface  ;  it  supports  the  anterior  margin  of  the 
horizontal  part  of  the  palate-bone.  The  pala- 
tine division  of  the  internal  surface  of  the  upper 
maxillary  bone  is  narrow,  and  forms  part  of 
the  arched  roof  of  the  mouth  ;  along  its  junc- 
tion with  the  palatine  process  is  a  broad  shal- 


FACE. 


20? 


low  groove  for  lodging  the  posterior  palatine 
nerves  and  vessels.  The  nasal  portion  of  the 
internal  surface  is  placed  above  the  palatine 
process,  and  is  lined  on  its  anterior  three-fourths 
by  the  pituitary  membrane.  Tracing  this  sur- 
face from  before  backwards  we  observe,  1.  the 
lower  aperture  of  the  naso-lachrymal  canal, 
situate  just  behind  the  inferior  turbinated  crest 
of  the  nasal  process ;  2.  posterior  to  this,  the 
orifice  of  the  maxillary  sinus,  or  antrum  of 
Highmore,  which  in  the  sepaiated  bone  is  a 
large  opening,  but  is  contracted  in  the  united 
face  by  the  lachrymal,  the  ethmoid,  the  palate, 
and  the  inferior  turbinated  bones,  which  are 
attached  around  its  margin.  Above  this  aper- 
ture are  seen  some  cells  which  unite  with  those 
of  the  ethmoid,  and  its  lower  edge  presents  a 
fissure  in  which  is  received  the  maxillary  pro- 
cess of  the  palate-bone.  Below  the  inferior 
turbinated  crest,  the  naso-lachrymal  canal  and 
the  orifice  of  the  antrum,  the  bone  is  concave 
and  smooth,  and  forms  a  part  of  the  inferior 
meatus  of  the  nose;  behind  this  smooth  surface 
and  the  orifice  of  the  antrum,  the  bone  is 
rough  for  the  attachment  of  the  vertical  plate 
of  the  os  palati,  and  it  presents  a  groove,  which, 
descending  obliquely  forwards  to  the  palatine 
division  of  this  surface,  forms  a  part  of  the 
posterior  palatine  canal. 

The  rnaxil/ary  sinus  (sinus  maxillaris,  antrum 
Hig/irnori ;  Germ,  die  Oberkieferhohlc)  oc- 
cupies in  the  adult  the  whole  body  of  the 
bone :  its  form  is  triangular,  with  the  base 
directed  internally  towards  the  orifice  which 
has  been  already  described,  and  the  apex  out- 
wards towards  the  malar  process.  Its  superior 
wall  is  formed  by  the  orbitar  plate;  the  pos- 
terior corresponds  to  the  maxillary  tuberosity  ; 
and  the  anterior  to  the  canine  fossa.  All 
these  walls  present  ridges  or  crests,  which 
lodge  canals  for  the  passage  of  nerves.  The 
posterior  and  anterior  walls  contain  the  su- 
perior, anterior,  and  posterior  dental  canals, 
which  lodge  nerves  of  the  same  name.  The 
upper  wall  contains  the  infra-orbitar  groove 
and  canal,  which  gives  passage  to  the  upper 
maxillary  nerve. 

Borders. — 1 .  The  anterior  or  naso-maxillary 
border  is  united  above  along  the  nasal  process 
to  the  nasal  bone.  Below  this  it  is  thin  and 
presents  a  deep  semicircular  notch,  which  forms 
the  lateral  and  inferior  portions  of  the  anterior 
aperture  of  the  nose.  At  the  lower  extremity 
of  this  notch  the  bone  projects,  and  forms 
with  its  fellow  of  the  opposite  side  the  anterior 
nasal  spine.  The  remainder  of  this  border 
proceeds  downwards  and  a  little  forwards  to 
terminate  on  the  alveolar  border  of  the  bone 
between  the  two  middle  incisor  teeth. 

2.  The  posterior  or  pterygo-pa/atine  border, 
thick,  rounded,  and  vertical,  is  united  below 
to  the  palate  bone,  and  above  it  forms,  with 
the  palate  bone,  the  anterior  border  of  the 
pterygo-maxillary  fissure. 

3.  The  inferior  or  alveolar  border  is  thick 
and  broad,  especially  behind,  and  forms  about 
the  fourth  of  an  oval.  It  is  perforated  with 
conical  cavities  (alveoli )  for  the  reception  of 
the  roots  of  eight  teeth.    These  cavities  are 

VOL.  It. 


separated  by  thin  transverse  laminae.  Tracing 
them  backwards  from  the  anterior  extremity 
of  the  border,  the  orifices  of  the  two  first 
are  nearly  circular,  and  receive  the  incisors  ; 
they  are  the  largest,  and  are  placed  below  the 
nasal  notch.  The  third,  in  form  transversely 
oval,  receives  the  canine  tooth,  is  of  great 
depth,  and  ascends  in  front  of  the  canine  fossa. 
The  fourth  and  fifth,  also  transversely  oval, 
but  not  so  deep,  receive  the  lesser  molar 
teeth ;  they  generally  present  ridges  in  their 
septa  which  correspond  to  grooves  in  the  fangs 
of  the  teeth  which  are  implanted  into  them. 

The  orifices  of  the  three  last  cavities  are 
quadrilateral,  and  receive  the  molar  teeth. 
The  sixth  and  seventh  are  subdivided  into 
three  lesser  cavities,  of  which  the  two  external 
are  smaller  than  the  inner  one.  Sometimes 
one  of  the  molar  teeth  has  four  fangs,  and 
then  we  find  its  socket  subdivided  into  a  cor- 
responding number  of  cavities.  The  eighth 
alveolus,  which  receives  the  last  molar  tooth 
or  dens  sapiential,  is  not  so  distinctly  divided 
into  subordinate  cavities,  but  presents  ridges 
like  the  lesser  molar.  The  outline  of  the 
alveolar  border  is  waving,  convex  where  it 
corresponds  to  the  alveoli,  and  depressed  op- 
posite their  septa.  The  whole  of  this  border 
is  covered  by  the  gums,  and  presents  innu- 
merable pores  for  the  nutritious  vessels.  The 
surfaces  of  the  alveoli  are  also  similarly 
marked. 

Connexions. —  The  upper  maxillary  articu- 
lates with  two  bones  of  the  cranium,  viz.  the 
ethmoid  and  frontal,  and  sometimes  with  the 
sphenoid  by  its  pterygoid  processes,  or  by  an 
union  of  the  orbitar  plates  of  both  bones  at 
the  outer  extremity  of  the  spheno-maxillary 
fissure.  In  this  case  the  malar  bone  does  not 
enter  into  the  formation  of  this  fissure.  The 
upper  maxillary  articulates  with  its  fellow 
and  with  all  the  bones  of  the  face.  The  me- 
dian and  lateral  cartilages  of  the  nose  are  at- 
tached to  it.  It  receives  the  upper  teeth,  and 
gives  attachment  to  eight  muscles,  viz.  the 
orbicularis  palpebrarum,  the  inferior  oblique 
of  the  eye,  the  levator  labii  superioris  alaeque 
nasi,  the  levator  labii  proprius,  the  depressor 
alae  nasi,  the  compressor  narium,  the  levator 
anguli  oris,  and  the  buccinator ;  often  also 
to  some  of  the  fibres  of  the  temporal  and 
the  external  pterygoid  muscles.  It  lodges  the 
naso-palatine  ganglion,  and  gives  passage  to 
the  infra-orbitar  and  to  the  anterior  and  pos- 
terior palatine  and  dental  vessels  and  nerves. 
It  forms  the  greater  part  of  the  sides  of  the 
nose,  and  of  the  floor  of  that  cavity,  and 
of  the  orbit,  as  well  as  of  the  roof  of  the 
mouth.  It  contains  the  maxillary  sinus  and  the 
nasal  duct. 

Structure. — This  bone  is  lighter  than  might 
be  expected  from  its  size,  being  occupied  by  the 
large  antrum  maxillare.  It  is  cancellous  only 
at  the  tuberosity,  along  the  alveolar  border, 
and  at  the  malar  and  palatine  processes. 

Developement. — The  ossification  of  this  bone 
commences  as  early  as  the  thirtieth  or  thirty- 
fifth  day  of  fipetal  life,  near  its  alveolar  border, 
and   it  is  complete  at  birth.    It  presents  at 

p 


210 


FACE. 


this  period,  and  often  much  later,  two  remark- 
able fissures.  1.  The  incisive  fissure,  which 
may  be  traced  from  the  alveolar  border  be- 
tween the  canine  and  lateral  incisor  tooth 
backwards  and  upwards,  along  the  incisive 
canal  towards  the  nasal  process :  it  is  sel- 
dom observable  on  the  facial  surface  of  the 
bone.  The  part  of  the  bone  circumscribed  by 
this  fissure  appears  to  correspond  to  the  inter- 
maxillary bone  of  animals,  and  is  probably 
developed  as  a  separate  piece  :  it  supports  the 
incisor  teeth.  2.  A  fissure  is  often  found  ex- 
tending from  the  infra-orbitar  groove  forwards 
to  the  orifice  of  the  canal.  The  existence  of 
these  fissures  has  led  some  anatomists  to  sup- 
pose that  the  bone  is  developed  by  these  ossitic 
points. 

At  birth  and  in  infancy  the  bone  presents  a 
much  greater  proportion  from  before  back- 
wards than  vertically :  its  nasal  process  is  long, 
its  orbitar  plate  large,  the  antrum  is  already 
distinct,  the  tuberosity  prominent,  and  there 
are  some  remarkable  holes  behind  the  incisor 
teeth,  which  are  said  to  have  an  important 
connexion  with  the  development  of  the  second 
set  of  teeth. 

In  the  adult  the  increase  in  the  vertical  di- 
mensions corresponds  with  the  developement 
of  the  antrum  and  alveolar  border.  In  old 
age  the  alveoli  are  obliterated,  the  border  con- 
tracts, and  the  jaw  diminishes  in  height.  In 
the  small  vertical  diameter  the  senile  and  in- 
fantile upper  jaw  bear  a  resemblance  to  each 
other. 

In  the  inferior  mammalia,  the  maxillary 
bones  are  separated  anteriorly  in  the  middle 
line  by  a  bone  called  os  intermaxillare  or 
incisivum,  which  contains  the  superior  incisor 
teeth  when  they  are  present ;  sometimes  this 
bone  is  distinctly  divisible  into  two  by  suture. 
This  bone  is  present,  although  the  superior 
incisors  be  absent,  as  in  Ruminants  and  Eden- 
tata, but  in  such  cases  is  very  small:  on  the 
other  hand,  when  the  incisor  teeth  are  largely 
developed,  it  is  of  considerable  size,  as  in  the 
Rodentia.  In  the  mature  human  foetus  no  sign 
of  this  bone  exists,  but  in  examining  the  skulls 
of  foetuses  about  the  third  or  fourth  month  of 
pregnancy,  we  observe  it  perfectly  distinct  from 
the  maxillary  bone.  It  sometimes  happens 
that  at  more  advanced  periods,  whether  of  in- 
tra or  extra-uterine  life,  evidence  of  the  separa- 
tion of  the  intermaxillary  bone  exists,  and  as 
Meckel  says,  we  often  find  a  transverse  narrow 
"  lacuna"  on  the  vault  of  the  palate,  extending 
from  the  external  incisor  tooth  to  the  anterior 
palatine  foramen.  According  to  Weber,  how- 
ever, who  examined  the  extensive  collection  of 
foetal  skeletons  belonging  to  Professor  Ilg  in 
Prague,  the  intermaxillary  bone  was  distinct 
only  in  those  that  had  a  double  hare-lip.  He 
considers,  however,  that  the  intermaxillary  bone 
readily  separates  when  the  skull  of  a  child  of 
one  or  two  years  old  is  placed  for  some  time 
in  dilute  muriatic  acid.* 

The  palate  bones,  ( ossa  palatinu  ;  Germ. 

*  See  Weber  in  Kroriep's  Notizen,  1820,  quoted 
in  Hildebrandt's  Anatomie,  B.  ii.  S.  95. 


die  Saumenbeine,)  situated  at  the  back  part  of 
the  nose  and  roof  of  the  mouth,  locked  be- 
tween the  maxillary  bones  and  pterygoid  pro- 
cesses of  the  sphenoid,  consist  of  two  thin 
plates,  one  short  and  horizontal,  the  palatine  ; 
the  other  long  and  vertical,  the  nasal.  The 
palatine  process,  or  plate,  has  two  surfaces  and 
four  borders.  The  upper  surface,  or  the  nasal, 
is  smooth  and  concave,  and  forms  the  posterior 
fourth  of  the  floor  of  the  nose.  The  lower  sur- 
face, the  palatine,  rough,  and  slightly  concave 
anteriorly,  has  on  its  posterior  and  outer  part  a 
transverse  crest  with  a  depression  behind  it  for 
theattachmentof  thecircumflexus  palati  muscle. 
In  front  and  to  the  outer  side  of  this  is  the 
inferior  orifice  of  the  posterior  palatine  canal, 
behind  which  are  two  or  three  small  openings 
called  accessoi'y  palatine  holes,  and  in  front  of 
it  is  the  commencement  of  the  groove  which 
lodges  the  posterior  palatine  vessels  and  nerves. 

The  anterior  border  is  cut  obliquely  from 
below  upwards  and  forwards,  and  rests  on  the 
posterior  border  of  the  palatine  plate  of  the 
upper  maxillary  bone,  forming  with  it  the 
transverse  palato-maxillary  suture.  The  pos- 
terior border,  thin  and  concave,  gives  attach- 
ment to  the  soft  palate. 

The  internal  border,  rough  and  thick,  is 
united  to  its  fellow  of  the  opposite  side ; 
above,  it  forms  a  grooved  crest,  which  receives 
a  part  of  the  vomer,  and  is  continuous  with  a 
similar  crest  formed  on  the  internal  border  of 
the  palatine  plate  of  the  upper  maxillary  bone. 
Behind,  this  border  terminates  in  a  sharp 
point,  which,  in  conjunction  with  the  corres- 
ponding projection  of  the  opposite  bone,  forms 
the  postei-ior  nasal  spine,  to  which  the  levator 
uvulae  muscle  is  attached.  The  external  border 
is  continuous  with  the  vertical  plate. 

The  nasal  process,  or  plate,  has  two  surfaces 
and  four  borders.  The  internal  or  nasal  pre- 
sents, tracing  it  from  below  upwards,  1.  a 
smooth  concave  surface,  which  forms  part 
of  the  inferior  meatus :  2.  a  horizontal  crest, 
the  inferior  turbinated  crest,  for  the  attach- 
ment of  the  inferior  turbinated  bone  :  3.  ano- 
ther concave  surface  forming  part  of  the  mid- 
dle meatus :  4.  another  horizontal  crest  (the 
superior  turbinated  crest ),  shorter  than  the 
former,  for  the  attachment  of  the  middle  tur- 
binated bone  of  the  ethmoid.  This  surface  is 
covered  with  the  pituitary  membrane. 

The  external  or  zygomato-maxillury  surface 
is  rough  in  front,  where  it  rests  against  the 
upper  maxillary  bone ;  behind  this  the  lower 
two-thirds  are  marked  by  a  groove,  which,  in 
conjunction  with  one  on  the  upper  maxillary 
bone,  forms  the  posterior  palatine  canal. 
Above  this,  the  bone  is  smooth,  and  forms  the 
inner  and  deep  part  of  the  pterygo-maxillary 
fissure. 

The  anterior  border,  thin  and  projecting, 
forms  a  process  (the  maxillary )  which  is  re- 
ceived into  the  fissure  in  the  lower  edge  of  the 
orifice  of  the  maxillary  sinus. 

The  posterior  or  pterygoid  border  is  united 
to  the  anterior  border  of  the  pterygoid  process 
of  the  sphenoid  :  below,  it  becomes  broad 
and  is  continued  along  a  process  which  stands 


FACE. 


211 


downwards,  outwards,  and  backwards,  from 
the  angle  of  union  of  the  posterior  borders  of 
the  vertical  and  horizontal  plates  of  the  bone. 
This  process  is  the  pterygoid  or  pyramidal,  and 
presents  three  grooves  behind,  viz.  one  internal 
and  one  external,  (of  which  the  inner  is  the 
deeper,)  for  the  reception  of  the  anterior  borders 
of  the  lower  extremity  of  the  pterygoid  plates  ; 
and  a  middle  triangular  groove  extending  high 
up,  and  which  forms  a  part  of  the  pterygoid  fossa. 
The  outer  surface  of  this  process  is  rough, 
and  is  articulated  with  the  upper  maxillary 
bone  :  its  apex  is  continuous  with  the  external 
pterygoid  plate. 

The  inferior  border  is  united  to  the  horizon- 
tal plate. 

The  superior  border  presents  a  deep  semi- 
circular notch  (sometimes  a  hole),  which  with 
the  sphenoid  bone  above  forms  the  spheno- 
palatineforamen.  This  notch  divides  the  upper 
border  into  two  processes,  1.  the  posterior  (the 
sphenoidal);  2.  the  anterior  (the  orbitar).  The 
sphenoidal  process  is  curved  inwards  and  back- 
wards, and  has  three  surfaces,  1.  an  internal  or 
nasal,  forming  part  of  the  cavity  of  the  nose; 
2.  an  external,  which  forms  below  the  spheno- 
palatine foramen  the  deep  wall  of  the  pterygo- 
maxillary  fissure ;  3.  an  upper,  which  is  con- 
cave and  rests  against  the  body  of  the  sphenoid 
bone,  and  contributes  to  the  pterygo-palatine 
canal. 

The  orbitar  process  stands  upwards  and 
outwards  on  a  narrow  neck,  and  presents  five 
surfaces.  1.  The  anterior  (or  maxillary)  arti- 
culates with  the  upper  maxillary  bone.  2.  The 
internal  (or  ethmoidal)  forms  a  cell  which  unites 
with  those  of  the  ethmoid.  3.  A  posterior 
(or  sphenoidal)  presents  a  cell  uniting  with  the 
sphenoid,  and  communicating  with  its  sinuses. 
4.  The  superior  (or  orbitar),  which  is  smooth 
and  contributes  to  form  the  floor  of  the  orbit: 
its  posterior  border  forms  a  part  of  the  spheno- 
maxillary fissure,  and  separates  the  orbitar  sur- 
face from,  5.  the  external  or  zygomatic,  which 
looks  into  the  pterygo-maxillary  fissure. 

Connexions. —  Each  palate  bone  articulates 
with  five  bones,  viz.  two  of  the  cranium,  the 
sphenoid  and  the  ethmoid  ;  and  with  three  of 
the  face,  the  upper  maxillary,  the  inferior  turbi- 
nated, and  the  vomer,  besides  its  fellow  bone  of 
the  opposite  side.  It  is  lined  with  the  buccal 
and  pituitary  membrane.  It  contributes  to  form 
the  cavities  of  the  mouth,  nose,  and  orbit ;  the 
pterygo-maxillary  fissure,  and  the  zygomatic  and 
pterygoid  fossae.  It  gives  attachment  to  the 
soft  palate,  and  passage  to  the  spheno-palatine, 
pterygo-palatine,  and  posterior  palatine  vessels 
and  nerves ;  also  to  the  two  pterygoid  muscles, 
the  circumflexus  palati,  the  levator  uvulae,  the 
palato-glossus,  and  the  palato-pharyngeus. 

The  structure  is  compact,  except  at  its  pte- 
rygoid process,  where  it  is  cancellous. 

Developement. — It  is  complete  at  birth,  ex- 
cept that  the  vertical  plate  is  short  to  corre- 
spond with  the  short  vertical  diameter  of  the 
upper  maxillary.  About  the  third  month 
ossification  appears  in  a  single  point,  at  the 
junction  of  the  two  plates  with  the  pyramidal 
process. 


Malar  bones  (ossa  mala-  v.  malaria  v.  zygo- 
matica  ;  Fr.  os  de  la  pommette ;  Germ,  die 
Jochbeine  oder  Backenbeine). — These  bones, 
corresponding  in  situation  to  the  prominence  of 
the  cheeks,  are  somewhat  of  a  quadrilateral 
figure.  Each  presents  three  surfaces;  1.  an 
external  ox  facial;  2.  an  internal  or  temporo- 
zygomatic ;  3.  a  superior  or  orbitar.  There 
are  besides  four  borders  and  four  angles. 

The  facial  surface  forms  the  eminence  of  the 
cheek,  looks  outwards  and  forwards,  is  smooth 
and  slightly  convex  in  front,  and  is  marked  by 
one  or  more  small  holes  (malar  foramina), 
which  give  passage  to  vessels  and  nerves.  It  is 
covered  above  by  the  integuments  and  the  orbi- 
cularis palpebrarum,  and  below  and  externally 
it  gives  attachment  to  the  zygomatic  muscles. 

The  temporo-zygomatic  surface  is  smooth 
and  concave  below  ;  and  internally  there  is  a 
rough  surface  which  rests  on  the  malar  process 
of  the  upper  maxillary  :  about  the  centre  or  to- 
wards the  upper  part  of  this  surface  is  observed 
the  internal  orifice  of  a  malar  canal  or  a  malar 
hole.  The  temporal  muscle  is  attached  to  this 
surface. 

The  orbitar  surface  is  smooth,  concave,  and 
is  formed  upon  a  plate  of  bone  ( the  orbitar 
process ),  which  stands  inwards,  and  contributes 
to  the  outer  wall  and  floor  of  the  orbit :  its  op- 
posite surface  above  makes  part  of  the  tempo- 
ral fossa.  On  the  orbitar  surface  we  observe 
the  orifice  of  a  malar  canal.  The  orbitar  pro- 
cess has  an  irregular  summit,  which  receives 
the  frontal  bone  ;  below,  it  is  articulated  with 
the  outer  border  of  the  orbitar  plate  of  the 
sphenoid ;  in  the  middle  it  corresponds  to  the 
extremity  of  the  spheno-maxillary  fissure  ;  and 
inferiorly  it  is  united  to  the  outer  border  of  the 
orbitar  plate  of  the  upper  maxillary  bone. 

Of  the  four  borders  two  are  anterior  and  two 
posterior.  The  anterior  superior,  or  the  orbi- 
tar, is  smooth,  concave,  and  forms  the  outer 
and  lower  third  of  the  base  of  the  orbit.  The 
anterior  inferior,  or  the  maxillary,  rests  upon 
the  malar  process  of  the  upper  maxilla  from  its 
extremity  to  the  inferior  orbitar  foramen.  The 
posterior  superior,  or  temporal  border,  is  waved 
like  the  letter  S,  and  gives  attachment  to  the 
temporal  fascia.  The  posterior  inferior,  or 
masseteric  border,  is  thick,  and  gives  attach- 
ment to  a  muscle  of  the  same  name.  The  four 
angles  are,  1 .  thick,  rough,  superior  or  frontal, 
which  receives  the  external  angular  process  of 
the  frontal  bone;  2.  the  interior  or  orbitar, 
which  is  pointed  ;  and,  3.  the  inferior  or  malar, 
which  is  round,  and  forms  the  extremities  of 
the  maxillary  border,  and  which  rests  on  the 
malar  process  of  that  bone.  The  posterior  or 
zygomatic  is  cut  obliquely  from  above  down- 
wards and  backwards,  and  supports  the  zygo- 
matic process  of  the  temporal  bone. 

Connexions. — The  malar  is  connected  with 
and  locked  between  four  bones,  viz.  the  frontal, 
the  sphenoid,  the  upper  maxillary,  and  the 
temporal.  It  contributes  to  form  the  orbit,  the 
temporal,  and  the  zygomatic  fossae.  It  gives 
attachment  to  four  muscles,  viz.  the  temporal, 
the  masseter,  and  the  two  zygomatic ;  and  it 
gives  passage  to  malar  vessels  and  nerves. 


212 


FACE. 


The  structure  is  compact,  except  near  its 
upper  and  lower  angles,  where  there  is  some 
cancellous  tissue. 

Developement . — Its  ossification  commences 
in  one  piece  about  the  fiftieth  day,  and  is  com- 
pleted at  birth,  when  the  bone  appears  thicker, 
and  its  orbitar  plate  larger  in  proportion  than 
in  the  adult :  its  vertical  diameter  is,  however, 
narrow,  and  the  malar  holes  are  large. 

The  nasal  bones  (ossa  nasi;  Germ,  die 
Nusenbeine )  form  the  upper  part  of  the 
nose,  and  are  placed  between  the  nasal  pro- 
cesses of  the  upper  maxillary  and  below  the 
frontal  bones,  inclining  from  above  downwards 
and  forwards.  They  have  two  surfaces,  and 
their  form  is  quadrilateral,  the  vertical  exceed- 
ing the  transverse  diameter.  They  are  stout 
and  narrow  above,  and  thin  and  broader  below. 

The  anterior  or  cutaneous  surface  is  smooth, 
covered  by  the  integuments  and  pyramidalis 
muscle,  concave  from  above  downwards,  con- 
vex transversely.  An  oblique  hole  for  the 
passage  of  vessels  is  usually  found  above  the 
centre  of  one  or  both  nasal  bones,  and  some 
smaller  foramina  are  scattered  over  the  surface. 

The  posterior  or  pituitary  surface  is  concave, 
narrow,  especially  above,  and  lined  by  the 
olfactory  membrane,  presenting  grooves  for 
vessels  and  the  internal  orifice  of  the  canal  (or 
hole)  mentioned  above. 

The  borders  are  four :  a  superior,  short, 
thick,  dentated,  inclined  from  above  down- 
wards and  backwards,  and  resting  on  the  nasal 
notch  of  the  frontal  bone  between  its  two  in- 
ternal angular  processes  :  the  inferior  border, 
longer  than  the  preceding,  thin,  jagged,  in- 
clining from  the  median  line  downwards  and 
outwards,  and  generally  presenting  about  its 
centre  a  slight  notch  for  the  passage  for  a  fila- 
ment of  the  nasal  nerve.  This  border  forms 
the  upper  and  front  part  of  the  anterior  opening 
of  the  nasal  fossa,  and  gives  attachment  to  the 
lateral  cartilages  of  the  nose.  The  external 
border  is  the  longest,  and  is  cut  obliquely  for 
its  articulation  with  the  nasal  process  of  the 
upper  maxillary  bone.  The  internal  border  is 
shorter,  thick  and  rough  above,  and  thin  be- 
low :  it  forms,  on  the  inner  aspect  of  the  bone, 
in  conjunction  with  the  corresponding  part  of 
the  bone  of  the  opposite  side,  a  ridge  and 
groove  for  the  reception  of  the  nasal  process  or 
spine  of  the  frontal  bone,  and  for  the  upper  and 
anterior  border  of  the  perpendicular  plate  of 
the  ethmoid. 

Connexions.  —  The  nasal  bones  articulate 
with  each  other,  with  the  frontal,  ethmoid,  and 
upper  maxillary  bones,  and  with  the  lateral 
cartilages  of  the  nose  :  they  form  a  part  of  the 
cavity  of  the  nose. 

Their  structure  is  cancellous  and  thick  above, 
thin  and  compact  below. 

Developement. — They  are  perfectly  ossified 
at  birth,  when  they  are  proportionally  longer 
than  in  the  adult,  corresponding  in  this  respect 
with  the  depth  of  the  orbit  and  the  smallness  of 
the  anterior  aperture  of  the  nose.  The  ossifica- 
tion of  each  nasal  bone  commences  by  a  single 
point  about  the  beginning  of  the  third  month. 
The  lachrymal  bones  ( ossa  unguis  v.  lachry- 


malia  ;  Germ,  die  Thrdnenbeine )  are  qua- 
drilateral in  form,  thin,  semitransparent,  and 
are  situated  on  the  anterior  part  of  the  inner 
wall  of  the  orbit  between  the  ethmoid,  frontal, 
and  upper  maxillary  bones  ;  they  derive  one 
of  their  names  from  the  resemblance  which 
they  bear  to  a  finger-nail.  Each  bone  presents 
two  surfaces  and  four  borders. 

The  external  or  orbitar  surface  is  divided  at 
its  anterior  third  by  a  vertical  crest,  terminating 
below  in  a  little  curved  process  which  forms 
the  outer  wall  of  the  upper  orifice  of  the  nasal 
canal ;  in  front  of  this  crest  the  bone  is  per- 
forated with  numerous  little  holes,  and  its  sur- 
face is  concave  and  forms  with  that  of  the 
nasal  process  of  the  upper  maxilla  the  canal 
for  the  lachrymal  sac.  The  posterior  part  of 
this  surface  is  smooth,  nearly  flat,  and  is 
continuous  with  that  of  the  os  planum  of  the 
ethmoid,  which  lies  immediately  behind  it. 

The  internal  or  ethmoidal  surface  is  rough, 
and  is  divided  by  a  vertical  groove,  which 
corresponds  to  the  crest  on  the  orbitar  aspect 
of  the  bone ;  the  anterior  division  is  convex 
and  forms  part  of  the  middle  meatus;  the  pos- 
terior division,  is  in  contact  with  the  ethmoid 
and  contributes  to  close  its  cells. 

Of  the  four  borders,  the  superior  is  the 
shortest  and  thickest ;  it  is  irregular  and  arti- 
culates with  the  inner  border  of  the  orbitar 
plate  of  the  os  frontis.  The  inferior  is  divided 
into  two  parts  by  the  lower  extremity  of  the 
crest  already  described  on  the  anterior  surface 
of  the  bone ;  in  front  of  this  the  border  de- 
scends along  a  thin  process  or  angle  of  the 
bone,  which  is  articulated  with  the  inferior 
turbinated  bone,  and  contributes  to  form  the 
inner  wall  of  the  canal  for  the  nasal  duct ; 
behind,  this  border  is  broad,  and  rests  on  the 
inner  margin  of  the  orbitar  plate  of  the  upper 
maxillary  bone.  The  anterior  border  is  slightly 
grooved  for  the  reception  of  the  inner  margin 
of  the  posterior  border  of  the  nasal  process 
belonging  to  the  upper  maxilla.  The  posterior 
border  is  thin  and  articulates  with  the  anterior 
edge  of  the  os  planum.  The  os  unguis  has 
four  angles,  of  which  the  anterior  inferior  is 
remarkable  for  its  length. 

Connexions. — This  bone  articulates  with  the 
frontal,  the  upper  maxillary,  the  ethmoid,  and 
the  inferior  turbinated ;  it  contributes  to  form 
part  of  the  orbit  of  the  cavity  of  the  nose  and 
of  the  groove  for  the  lachrymo-nasal  duct. 
It  gives  attachment  to  the  reflected  portion  of 
the  tendon  of  the  orbicularis  palpebrarum, 
and  to  the  tendon  of  the  tensor  tarsi  muscles. 
In  structure  it  is  thin  and  compact. 
Development. — It  is  complete  at  birth,  ex- 
cept at  its  posterior  superior  angle,  where  there 
is  a  deficiency  between  it  and  the  frontal  and 
ethmoid  bones,  and  where  a  separate  piece  is 
sometimes  formed.  It  is  broader  from  back 
to  front  in  proportion,  at  this  period  of  life, 
than  in  the  adult,  and  its  lachrymal  groove  is 
larger.  Its  ossification  commences  by  a  single 
point  between  the  third  and  sixth  months. 

A  small  lachrymal  bone  has  been  described 
as  sometimes  found  at  the  lower  part  of  the 
os  unguis;  and  not  unfrequently  some  separate 


FACE, 


213 


pieces  are  found  at  its  angles,  formed  either 
from  the  ethmoid  or  from  the  orbitar  plate  of 
the  upper  maxillary  bone. 

The  inferior  turbinated  bones,  (ossa  spongiosa 
v.  turbinata  infima;  Germ,  die  untern  Muschel- 
beine )  of  an  oval  form,  thin  and  spongy  in  their 
appearance,  are  placed  horizontally  along  the 
lower  part  of  the  outer  wall  of  the  nasal  cavities, 
separating  the  middle  from  the  inferior  meatus, 
and  contributing  to  increase  the  surface  of  the 
nose.  Each  bone  presents  two  surfaces,  two 
borders,  and  two  extremities.  The  internal 
surface  is  rough,  convex,  and  looks  towards  the 
septum  of  the  nose,  which  it  sometimes  touches 
on  one  side  when  that  partition  inclines  more 
than  usually  to  the  right  or  left.  The  external 
surface  is  concave,  exhibiting  many  small 
fossae  or  pits ;  it  looks  towards  the  upper 
maxilla  and  forms  a  part  of  the  inferior  meatus. 
Both  surfaces  are  very  irregular  or  spongy  and 
are  pitted  by  vessels,  but  especially  by  veins, 
which  ramify  abundantly  upon  them.  The 
inferior  border  is  convex  and  thick,  particu- 
larly at  its  centre,  where  it  descends  towards 
the  floor  of  the  nose.  The  vpper  border  is 
thin  and  irregular,  and  presents  from  before 
backwards,  1.  a  thin  edge,  which  is  attached 
to  the  inferior  turbinated  crest  on  the  nasal 
process  of  the  upper  maxilla;  2.  a  process 
(the  lachrymal )  which  ascends  towards  the 
curved  process  of  the  os  unguis,  with  which  and 
with  the  adjacent  part  of  the  upper  jaw-bone  it 
unites  to  complete  the  canal  for  the  nasal  duct; 
3.  some  irregular  projections  ( ethmoidal  pro- 
cesses) which  ascend  and  unite  with  the 
ethmoid  ;  4.  a  thin,  curled,  dog's-ear-looking 
process  (the  auricular  or  maxillary ),  which, 
descending  and  overhanging  the  internal  sur- 
face of  the  bone,  is  attached  to  the  lower  part 
of  the  opening  of  the  antrum,  which  it  con- 
tributes to  circumscribe  ;  5.  an  edge  which  is 
articulated  with  the  inferior  turbinated  crest 
of  the  palate-bone.  The  orifice  of  the  antrum 
is  situated  just  above  the  centre  of  this  border, 
and  opens  consequently  into  the  middle  mea- 
tus. 

The  extremities  or  angles  are  formed  by  the 
union  of  the  two  borders  ;  the  posterior  extre- 
mity is  more  pointed  than  the  anterior. 

Connexions. —  Each  inferior  turbinated  is 
united  with  four  other  bones,  viz.  the  uppe* 
maxillary,  the  lachrymal,  the  ethmoid,  and  Jip 
palate.  It  is  covered  with  the  pituitary  me"ui- 
brane ;  it  contributes  to  enlarge  the  surface  of 
the  nasal  cavity,  and  to  form  a  part  of 
nasal  canal  and  middle  and  lower  meatus. 

Its  structure  is  compact. 

Its  development  commences  at  the  fifth  montti 
by  a  single  point  of  ossification. 

The  vomer  (Germ,  das  Pflugscharbein)  is 
of  a  quadrilateral  figure,  and  resembles  a 
ploughshare;  it  is  a  single  and  symmetrical 
bone,  situated  in  the  median  plane,  and  forming 
the  posterior  and  inferior  part  of  the  septum 
nasi.  It  has  two  lateral  surfaces  and  four 
borders.  The  surfaces,  which  are  right'  and 
left,  are  smooth,  flat,  and  lined  by  the  pitui- 
tary membrane;  sometimes,  when  the  bone 
inclines  much  to  either   side  of  the  nose, 


one  of  these  surfaces  is  convex  and  the  other 
concave  ;  they  present  an  oblique  groove  or 
grooves  for  the  naso-palatine  nerves  and 
vessels. 

The  superior  border  (or  surface)  is  broad, 
and  may  be  termed  the  base  of  the  bone ;  it 
presents  a  deep  groove  in  the  middle,  which 
receives  the  rostrum  of  the  sphenoid,  and  on 
each  side  of  this  are  two  plates  or  lamina? 
(sometimes  called  the  alee)  which  are  received 
into  fissures  of  the  sphenoid  on  each  side 
of  the  rostrum,  and  which  contribute  to  form  a 
longitudinal  canal  for  the  ethmoidal  vessels. 

The  anterior  border  is  oblique  from  above 
downwards  and  forwards;  above  it  presents  a 
deep  groove,  which  is  a  continuation  of  that 
on  the  upper  border,  and  which  receives  the 
perpendicular  plate  of  the  ethmoid :  below, 
this  border  is  nearly  flat,  where  it  is  united  to 
the  middle  cartilage  of  the  nose. 

The  inferior  border  is  the  longest,  and  is 
received  into  the  grooved  crest  formed  by  the 
united  palatine  plates  of  the  superior  maxillary 
and  palate  bones ;  in  front  this  border  extends 
as  far  as  the  anterior  nasal  spine. 

The  posterior  border,  thick  above,  thin  be- 
low, is  oblique,  slightly  curved,  and  forms  the 
partition  between  the  two  posterior  openings 
of  the  nose. 

Connexions.- — The  vomer  is  connected  with 
four  bones,  viz.  the  sphenoid  and  ethmoid 
above,  the  superior  maxillary  and  palate  below  : 
it  is  covered  with  the  pituitary  membrane,  and 
forms,  with  the  perpendicular  plate  of  the 
ethmoid  and  the  middle  cartilage,  the  septum 
of  the  nose. 

Its  structure  is  compact,  and  it  is  formed 
of  two  thin  lateral  plates,  which  are  distinct 
above,  but  united  inferiorly. 

Its  development  occurs  by  a  single  ossific 
point  about  the  third  month,  and  at  birth  it  is 
completely  ossified. 

The  os  maxillare  informs  (Germ,  das  untere 
Kiunbackenbein,  oder  der  Unterkiefor).  This 
single  bone,  which  alone  forms  the  lower  jaw, 
occupies  the  lower  and  lateral  parts  of  the  face  ; 
it  is  a  flat,  symmetrical  bone,  and  bears  some 
resemblance  in  shape  to  a  horse-shoe.  It  con- 
sists of  a  middleor  horizontal  portion  (the  body ), 
and  of  two  lateral  ascending  branches  (the  rami), 
which  are  connected  with  the  body  nearly  at 
right  angles. 

The  body  is  curved,  nearly  horizontal,  in- 
clining from  before  backwards,  and  a  little 
upwards,  and  presents  two  surfaces  and  two 
^orders. 

The  anterior  surface  is  convex,  and  has  in 
the  centre  a  vertical  line  (crista  mentulis  ex- 
terna), which  marks  the  union  of  the  two 
hai  -  as  >.f  which  the  bone  consists  in  the  young 
subject :  this  line  terminates  below  in  a  tri- 
angular t.ninence  (the  mental  process).  The 
v$;,  a  .-u  direction  of  the  lower  jaw  at  the  sym- 
pl  i  ,  and  its  curved  figure  anteriorly,  form- 
ii  ;  h  it  is  termed  the  chin,  are  both  charac- 
terise of  the  human  race.  From  the  angles 
J  in'  mental  process  arises  on  each  side  the 
-external  oblique  line,  faintly  marked  in  front, 
but  becoming  distinct  as  it  ascends  diagonally 


214 


FACE. 


along  this  surface  of  the  bone  to  terminate  at 
the  anterior  border  of  the  ramus  of  the  jaw; 
it  gives  attachment  to  muscles  and  separates 
the  external  surface  of  the  bone  into  two  parts, 
viz.  an  anterior  superior,  which  presents,  ex- 
ternal to  the  symphysis,  1.  a  depression  (the 
J'ossa  mentalis )  for  the  attachment  of  a  muscle; 
2.  to  the  outer  side  of  this  the  mental  foramen, 
which  is  directed  obliquely  upwards  and  out- 
wards; it  is  the  lower  orifice  of  the  inferior 
dental  canal,  which  conveys  nerves  and  vessels 
to  the  teeth  of  the  lower  jaw;  3.  a  number  of 
ridges  and  grooves  near  the  alveolar  border  of 
the  jaw,  which  correspond  to  the  sockets  of  the 
teeth  and  to  the  septa  which  divide  them  : 
this  part  of  the  bone  is  covered  by  the  gums. 
The  surface  below  and  behind  the  oblique  line 
is  smooth,  or  only  faintly  marked  with  irre- 
gular lines  for  the  attachment  of  the  platysma 
myoides. 

The  intei-nal  surface  of  the  body  of  the 
lower  jaw  is  concave,  and  presents  in  the 
median  line,  at  the  symphysis,  a  vertical  crest 
(crista   merit alis   interna ),   which  is  not  so 
distinct  as  the  corresponding  ridge  on  the  outer 
surface  of  the  bone :  at  its  lower  extremity  is 
a  tubercle  having  four  summits  ( the  genial 
processes,  yiniov,  chin,  spina  interna,)  which 
give  attachment  to  two  pairs  of  muscles,  viz. 
the  two  superior  genial  processes  to  the  genio- 
hyo-glossi,  the   two   inferior  to  the  genio- 
hyoidei :  below  and  to  the  outer  side  of  these 
processes,  on  the  lower  border  of  the  bone, 
are  two  oval  rough  depressions,  one  on  each 
side  of  the  symphysis,  for  the  attachment  of 
the  anterior  bellies  of  the  digastric  muscles. 
From  the  genial  processes  proceeds  obliquely 
upwards  and  backwards,  to  join  the  anterior 
border  of  the  ramus  of  the  jaw,  the  internal 
oblique  line,  or  the  mylo-hyoid  ridge.    It  is 
distinctly  marked  and  very  prominent  oppo- 
site the  last  molar  tooth ;   like  the  external 
oblique  line  it  divides  the  bone  diagonally  into 
two  triangular  portions,  the  anterior  of  which, 
situated  above  and    in  front   of  the  ridge, 
is  smooth,  concave,  and  to  the  outer  side  of 
the  genial   processes  presents  a  depression 
( sublingual  J'ossa )  for  the  reception  of  the  sub- 
lingual gland  :  elsewhere  this  surface  is  lined 
by  the  gums,  and  forms  the  inner  wall  of  the 
alveolar  cavities;  but  it  is  destitute  of  the 
ridges  and  depressions  which  are  seen  on  the 
outer  surface  ot   the  bone.     The  triangular 
surface  below  the  oblique  line  is  marked  by 
numerous  small  holes  for  the  passage  of  nu- 
tritious vessels,  and  by  a  large  depression 
(the    submaxillary  J'ossa )   for  the  reception 
of  the  submaxillary  gland.    The  two  oblique 
maxillary  lines  which  have  been  just  described 
divide  the  body  of  the  jaw  into  two  portions, 
one  superior  or  alveolar,  the  other  inferior  or 
basilar:  in  the  foetus  the  former  predominates 
considerably;  in  the  adult  they  are  nearly 
equal,  and  in  the  edentulous  jaw  of  old  age 
the  body  almost  entirely  consists  of  the  basilar 
portion. 

The  upper  or  alveolar  border  forms  a  lesser 
curve  than  that  of  the  alveolar  border  of  the 
superior  maxilla  :   like  it,  however,  it  presents 


sockets  for  the  reception  of  sixteen  teeth,  which 
vary  also  in  form  and  depth  in  correspondence 
with  the  fangs  of  the  teeth  which  they  lodge. 
The  orifices  of  the  sockets,  however,  take  a 
direction  different  from  those  of  the  upper  jaw, 
for  while  the  sockets  of  the  upper  incisors  look 
downwards  and  forwards,  those  of  the  lower 
are  directed  upwards  and  backwards;  and 
again  the  alveoli  of  the  upper  canine  and 
molar  teeth  look  downwards  and  outwards, 
whereas  those  of  the  lower  are  directed  up- 
wards and  inwards :  hence,  from  this  different 
inclination  of  the  teeth  in  the  two  jaws,  and 
from  the  larger  curve  described  by  the  alveolar 
border  of  the  superior  maxilla,  we  find  that 
when  the  mouth  is  closed  the  upper  front  teeth 
cover  the  lower  and  at  the  sides  overhang 
them  a  little.  This  arrangement  is  favourable 
to  the  division  and  mastication  of  the  food. 

The  lower  border  or  base  is  smooth  and 
thick,  and  forms  a  larger  curve  than  the  upper, 
so  that  the  surfaces  of  this  jaw  have  an  in- 
clination from  above  downwards  and  forwards: 
it  forms  the  oval  border  of  the  lower  part 
of  the  face,  and  is  the  strongest  portion  of  the 
bone. 

The  rami  are  flat,  quadrilateral  processes, 
which  stand  up  from  the  body  of  the  jaw  at 
almost  a  right  angle :  in  the  child  and  old 
person  this  angle  is  much  more  obtuse.  Each 
ramus  presents  two  surfaces  and  four  borders. 

The  external  or  masseteric  surface  has  an 
inclination  from  above  downwards  and  more 
or  less  outwards  :  it  is  rough,  especially  below, 
where  it  presents  some  irregular  oblique  ridges 
and  depressions  for  the  attachment  of  the 
masseter:  in  front  of  these  marks,  near  the 
lower  border  of  the  bone,  there  is  often  a 
slight  groove,  which  indicates  the  course  of 
the  facial  vessels. 

The  internal  or  pterygoid  surface  is  also 
rough  below  for  the  attachment  of  the  internal 
pterygoid  muscle.  In  its  centre  is  the  spreading 
superior  orifice  (superior  dental  foramen)  of 
the  lower  dentul  canal,  marked  and  partly 
hidden  internally  by  a  spine,  which  gives 
attachment  to  the  internal  lateral  ligament  of 
the  temporo-maxillary  articulation  :  from  this 
hole,  taking  a  direction  downwards  and  for- 
wards is  a  groove  (the  mylo-hyoid  groove ), 
which  lodges  the  branch  of  the  inferior  dental 
artery  and  nerve. 

The  borders  of  the  rami  are,  an  anterior 
or  buccal,  grooved  below,  where  it  corre- 
sponds with  the  alveolar  border  of  the  bone ; 
the  margins  of  this  groove,  which  are  con- 
tinuous with  the  oblique  lines  of  the  bone, 
unite  above  and  form  a  sharp  convex  edge. 
The  posterior  or  parotid  border  is  round  and 
thick  above,  and  narrow  below,  and  is  em- 
braced by  the  parotid  gland  :  inferiorly  and 
internally  it  gives  attachment  to  the  stylo- 
maxillaiy  ligament.  The  superior  or  zygomatic 
border  is  sharp  and  concave,  forming  a  notch 
( the  sigmoid  notch ),  which  looks  upwards. 
The  inferior  border  is  rounded,  and  is  con- 
tinuous with  the  lower  border  of  the  body. 

The  angles  of  the  lower  jaw  are  formed 
by  the  union  of  the  body  and  rami ;  each 


FACE. 


215 


is  turned  a  little  outwards,  and  in  the  adult 
forms  nearly  a  right  angle ;  in  the  infant  and 
in  the  old  person  it  is  obtuse.  This  part  of 
the  bone  is  prominent  and  separates  the  in- 
sertion of  the  masseter  and  internal  pterygoid 
muscles. 

On  the  upper  part  of  each  ramus  stand 
two  processes,  which  are  separated  by  the 
sigmoid  notch  ;  the  anterior  is  the  coronoid, 
which  is  of  a  triangular  form,  flattened  laterally, 
and  sharp  in  front  and  behind  ;  its  summit 
is  somewhat  rounded  :  this  process  gives  at- 
tachment to  the  temporal  muscles.  The  con- 
dyloid process  is  situated  behind  the  sigmoid 
notch,  and  arises  from  the  ramus  by  a  narrow 
neck,  which  is  directed  upwards  and  a  little 
inwards,  swelling  above  into  an  oval  head 
or  condyle,  that  has  an  articular  surface  on 
its  summit.  This  articular  surface  is  trans- 
versely oval,  convex,  covered  in  the  recent 
subject  with  cartilage,  and  inclines  from  within 
outwards  and  a  little  forwards.  The  condyle, 
from  the  direction  of  its  neck,  somewhat  over- 
hangs the  internal  surface  of  the  ramus;  it 
is  articulated  with  the  anterior  division  of  the 
glenoid  cavity  of  the  temporal  bone.  The 
direction  and  form  of  its  articular  surfaces 
are  calculated  to  facilitate  the  rotatory  move- 
ments of  the  lower  jaw  during  mastication. 
In  front  the  neck  of  the  condyle  presents  a 
depression  for  the  attachment  of  the  external 
pterygoid  muscle. 

Structure. — The  lower  jaw  is  formed  of  two 
complete  plates,  united  by  cancellous  tissue, 
which  is  traversed  by  a  long  curved  canal  (the 
inferior  dental  canal),  which  conveys  the 
vessels  and  nerves  that  supply  the  teeth.  This 
canal  commences  in  a  groove  just  above  the 
superior  dental  foramen,  which  is  situated  on 
the  internal  surface  of  the  ramus ;  it  then 
enters  the  substance  of  the  bone,  taking  the 
course  of  the  internal  oblique  line  below,  and 
parallel  to  which  it  runs  as  far  as  the  second 
bicuspid  tooth,  where  it  divides  into  two 
canals,  one  short  and  wide,  which  terminates 
on  the  external  surface  of  the  bone  at  the 
inferior  dental  foramen  ;  and  another  smaller 
one,  which  continues  onwards  as  far  as  the 
middle  incisor  tooth,  where  it  ceases.  From 
the  upper  side  of  this  dental  canal  small  tubes 
arise,  which  proceed  to  the  alveoli  ;  they 
convey  vessels  and  nerves  to  the  fangs  of  the 
teeth.  The  situation  and  size  of  the  dental 
canal  vary  according  to  the  age  of  the  individual. 
At  birth  it  runs  near  the  lower  border  of  the 
bone,  and  is  of  considerable  magnitude;  after  the 
second  dentition  it  becomes  placed  just  below 
the  mylo-hyoid  ridge ;  in  the  edentulous  jaw 
it  runs  along  the  alveolar  border  of  the  bone, 
its  size  is  much  diminished,  and  the  mental 
foramen  is  found  close  upon  the  upper  border 
of  the  bone. 

Connexions  and  uses.- — The  lower  jaw  is  arti- 
culated with  the  temporal  bones,  and  receives 
the  sixteen  inferior  teeth.  It  gives  attachment 
to  fourteen  pairs  of  muscles,  viz.  the  temporal, 
the  masseter,  the  two  pterygoids,  the  bucci- 
nator, the  superior  constrictor  of  the  pharynx, 
the  depressor  anguli  oris,  the  depressor  iabii 


inferioris,  the  levator  menti,  the  platysma, 
the  genio-hyo-glossus,  the  genio-hyoideus,  the 
mylo-hyoideus,  and  the  digastric.  Four  pairs 
of  ligaments  are  attached  to  it,  viz.  the  external 
and  the  internal  lateral  ligaments  of  the  tem- 
poro-maxillary  articulation,  the  pterygo-maxil- 
lary  (or  intermaxillary)  ligament,  and  the  stylo- 
maxillary  ligament.  It  forms  the  lower  part 
of  the  face  and  the  cavity  of  the  mouth ;  it 
protects  the  tongue,  salivary  gland,  and  pharynx ; 
it  differs  from  the  upper  jaw  and  from  all  the 
other  bones  of  the  head  in  its  remarkable 
mobility ;  and  it  contributes  essentially  to 
mastication  as  well  as  to  deglutition  and 
articulation. 

Development.- — The  lower  jaw  at  birth  con- 
sists of  two  lateral  halves,  which  are  united 
vertically  in  front  along  the  median  line  by 
a  piece  of  cartilage,  forming  what  has  been 
improperly  called  a  symphysis.  A  few  months 
after  birth  the  removal  of  this  cartilage  com- 
mences, and  the  two  halves  of  the  bone 
become  united  below;  but  not  unfrequently 
a  fissure  remains  above  for  several  months. 
At  this  period  the  alveolar  border  is,  like  that 
of  the  upper  jaw,  very  thick,  and  contains 
some  large  irregular  cavities  which  lodge  the 
first  set  of  teeth.  Besides  the  superior  dental 
foramen  there  is  found  in  the  foetus  another, 
which  leads  to  a  temporary  canal  that  supplies 
the  first  set  of  teeth,  and  behind  the  alveoli 
of  the  incisors  may  be  observed  a  row  of  holes 
which  are  said  to  be  connected  with  the  de- 
velopment of  the  second  set  of  teeth.  Some 
authors  maintain  that  each  side  of  the  lower 
jaw  is  developed  by  four  separate  points  of 
ossification  ;  but  this  assertion  wants  confirma- 
tion. It  is  certain  that  this  bone  is  among 
those  which  are  the  most  early  developed,  and 
in  the  embryo  of  two  months  it  is  already 
of  considerable  size.  Its  alveolar  border  is 
at  first  a  mere  groove,  of  which  the  internal 
margin  is  defective,  and  which  gradually  be- 
comes hollowed  into  separate  sockets  as  the 
teeth  are  developed.  The  changes  of  form 
which  the  lower  jaw  undergoes  from  birth  till 
old  age  depend  chiefly  upon  the  development 
and  decay  of  the  teeth.  Some  of  these  changes 
have  been  already  noticed,  and  will  be  found 
to  correspond  with  those  which  occur  in  the 
alveolar  border  of  the  upper  maxilla;  the 
varying  form  and  direction  of  the  rami  and 
angles  of  the  lower  jaw  we  have  noticed, 
and  for  the  more  detailed  account  of  the  de- 
velopment of  this  bone  as  connected  with 
dentition,  we  refer  to  the  article  Teeth. 

Of  the  face  in  general. — Dimensions. — The 
vertical  diameter  of  the  face  is  the  greatest, 
and  extends  in  front  from  the  nasal  eminences 
of  the  frontal  bone  to  the  lower  border  of  the 
symphysis  menti ;  this  diameter  decreases  as 
we  trace  it  backwards.  The  transverse  dia- 
meter is  next  in  length  if  measured  at  the 
level  of  the  malar  bone,  where  it  is  most  con- 
siderable; below  and  above  this  it  gradually 
diminishes.  The  antero-posterior  diameter  is 
greatest  at  the  level  of  the  cheek-bones,  where  it 
extends  from  the  cuneiform  process  of  the  occi- 
pital boneto  the  anterior  nasal  spine  of  the  upper 


216 


FACE. 


maxilla ;  this  diameter  also  diminishes  both 
above  and  below,  but  more  especially  below, 
where  it  comprises  merely  the  thickness  of 
the  mental  portion  of  the  lower  jaw. 

The  bones  which  form  the  upper  jaw  are 
united  with  those  of  the  cranium  above  by  a 
very  irregular  surface ;  below  they  are  on  a 
level  with  the  occipital  foramen,  and  hence 
that  part  of  the  face  which  descends  below 
the  cranium  is  formed  exclusively  by  the  lower 
jaw. 

The  area  of  the  face,  as  presented  by  a 
vertical  longitudinal  section  of  the  skull,  is 
of  a  triangular  figure,  and  forms  (the  lower 
jaw  excepted)  in  the  European  about  one- 
fifth  of  the  whole  area  of  the  skull ;  in  the 
Negro  the  area  of  the  face  increases  in  propor- 
tion, and  forms  two-fifths  of  the  whole. 

The  bones  of  the  face  form,  when  united, 
a  pyramid  with  four  irregular  surfaces  or 
regions,  and  presenting  a  base  above,  which 
is  connected  with  the  cranium,  an  apex  below 
at  the  chin. 

The  anterior  surface  or  facial  region  presents 
many  varieties  of  form  and  proportion  in 
different  individuals,  as  well  as  others  more 
important,  which  characterise  the  various  races  of 
mankind  :  (see  the  article  Man.)  This  region 
is  bounded  above  by  the  lower  border  of  the 
frontal  bone,  extended  between  its  two  external 
angular  processes:  laterally  it  is  limited  by 
lines  drawn  from  these  processes  to  the  anterior 
inferior  angles  of  the  malar  bones :  below  this 
it  follows  the  curve  of  the  malar  ridge  of  the 
upper  maxilla,  and  it  terminates  at  the  outer 
extremity  of  the  base  of  the  lower  jaw.  This 
surface  presents  from  above  downwards  along 
the  median  line,  the  fronto-nasal  suture,  which 
is  continued  laterally  into  the  fronto-maxillary 
and  fronto-ethmoidal  sutures,  all  contributing 
to  form  the  common  transverse  facial  suture 
which  unites  the  bones  of  the  cranium  and 
face.  Below  the  fronto-nasal  suture  the  nasal 
bones,  united  by  the  nasal  suture,  form  the 
prominent  arch  of  the  nose  in  conjunction 
with  the  nasal  processes  of  the  upper  maxillary 
bones,  with  which  the  ossa  nasi  articulate  on 
each  side  by  the  naso-maxillary  suture.  Below 
the  nasal  bones  is  the  anterior  orifice  of  the 
nasal  fossae,  of  apyriform  shape,  narrow  above, 
broad  inferiorly,  where  it  terminates  in  the 
projecting  anterior  nasal  spine  :  the  margins 
of  this  orifice  are  sharp,  and  are  formed  by 
the  nasal  and  upper  maxillary  bones.  Below 
the  nasal  spine  is  the  intermaxillary  suture, 
which  terminates  on  the  alveolar  border  of  the 
upper  jaw  between  the  middle  incisor  teeth  : 
on  each  side  of  this  suture  is  the  myrtiform 
fossa.  On  the  lower  jaw  is  observed,  in  the 
median  line,  the  mental  ridge  and  process, 
and  on  each  side  of  it  a  depression  for  muscles. 

The  facial  region  presents  from  above  down- 
wards, on  each  side,  the  aperture  or  base 
of  the  orbit,  of  a  quadilateral  form,  and  in- 
clining from  within  outwards  and  a  little  back- 
wards. The  margin  of  this  opening  is  formed 
above  by  the  supra-ciliary  ridge  of  the  frontal 
bone,  in  which  is  observed  the  supra-orbitar 
notch  or  foramen.    At  the  outer  extremity  of 


this  ridge  is  the  fronto-jugal  suture,  uniting 
the  external  angular  process  of  the  frontal 
bone  with  the  frontal  process  of  the  malar  : 
below  this  is  the  prominence  of  the  cheek 
and  the  curved  orbitar  border  of  the  malar 
bone,  forming  the  outer  and  lower  part  of 
the  margin  of  the  orbit.  Internal  to  this  we 
find  the  short  orbitar  border  of  the  upper 
maxillary  bone,  which  presents  at  its  nasal 
end  the  groove  for  the  lachrymal  sac.  Below 
the  inferior  border  of  the  orbit  is  the  infra- 
orbitar  foramen,  to  the  outer  side  of  which 
is  the  oblique  jugo-maxillary  suture,  and 
below  it  the  canine  fossa,  bounded  exter- 
nally by  the  malar  ridge,  in  front  by  the 
canine  ridge  and  the  anterior  orifice  of  the 
nose,  and  below  by  the  alveolar  border  of 
the  jaw  and  by  the  teeth.  On  the  lower  jaw 
we  find  the  teeth,  the  alveolar  ridges  and 
depressions,  the  mental  foramen,  and  the  ex- 
ternal oblique  line. 

The  posterior  or  guttural  surface  consists 
of  three  parts,  two  of  which,  the  upper  and 
lower,  are  vertical ;  the  middle  is  horizontal. 
The  upper  vertical  portion  presents  along  the 
median  line  the  oblique  posterior  border  of 
the  vomer,  which  divides  the  posterior  apertures 
of  the  nasal  fossae;  above  is  the  articulation 
formed  by  the  base  of  the  vomer  and  the 
sphenoid  ;  below  is  the  posterior  nasal  spine 
formed  by  the  united  palate  bones.  At  the 
sides  of  the  vomer  are  the  oval  posterior 
orifices  of  the  nose,  greatest  in  their  vertical 
diameter,  and  bounded  superiorly  by  the 
sphenoid  and  sphenoidal  processes  of  the 
palate  bones,  inferiorly  by  the  palatine  plates 
of  the  same  bones,  internally  by  the  vomer, 
and  externally  by  the  pterygoid  processes.  On 
the  outside  of  these  apertures  are  placed  the 
pterygoid  fossae,  formed  by  the  pterygoid  plates 
of  the  sphenoid  and  by  the  pyramidal  process 
of  the  palate  bone.  External  to  these  are  the 
large  zygomatic  fossae  or  spaces,  which  belong 
to  the  lateral  regions  of  the  face. 

The  horizontal  portion  of  this  surface  is 
oval,  concave,  rough,  and  forms  the  roof  of 
the  mouth,  consisting  of  the  palatine  plates 
of  the  palate  and  upper  maxillary  bones,  on 
which  is  seen  a  crucial  suture,  formed  by  the 
longitudinal  and  transverse  palatine  sutures. 
At  the  posterior  and  outer  angles  of  this  hori- 
zontal portion  are  situated  the  posterior  palatine 
canals  and  the  grooves  which  proceed  from 
them  along  the  roof  of  the  mouth ;  on  the 
inferior  surface  of  the  palate  bones  are  ridges 
and  depressions  for  the  attachment  of  muscles, 
while  behind  the  middle  incisor  teeth  is  placed 
the  anterior  palatine  foramen.  At  the  sides 
and  in  front  the  palatine  arch  is  bounded  by 
the  alveolar  border  and  teeth  of  the  upper 
jaw,  behind  which  descend  the  pterygoid  pro- 
cesses of  the  sphenoid  and  palate  bones. 

The  inferior  vertical  division  of  this  region 
is  formed  by  the  inner  surface  of  the  lower  jaw 
and  teeth ;  it  presents  in  front,  along  the 
median  line,  the  inner  mental  ridge,  and  the 
genial  processes ;  external  to  these  the  internal 
oblique  lines,  the  sublingual  and  submaxillary 
fossae,  the  superior  dental  foramen,  its  groove 


FACE. 


217 


and  process;  the  condyles  and  angles  of  the 
jaw,  its  alveolar  border  and  its  base,  which 
terminates  it  below,  and  near  which,  at  the 
chin,  are  seen  the  depressions  for  the  digastric 
muscles. 

The  lateral  or  zygomatic  surfaces  on  each 
side  are  bounded  above  by  the  temporal  border 
of  the  malar  bone  and  by  the  zygomatic  arch ; 
in  front  by  a  line  extended  vertically  from  the 
external  angular  process  of  the  frontal  bone  to 
the  base  of  the  lower  jaw,  and  behind  and 
below  by  the  free  border  of  the  body  and  ramus 
of  the  inferior  maxilla. 

This  region  presents  a  superficial  and  a  deep 
portion  :  the  former  comprises  the  lateral  aspect 
of  the  malar  bone,  the  zygomatic  arch,  and 
the  external  surface  of  the  ramus  of  the  jaw. 
On  it  we  may  remark,  proceeding  from  above 
downwards,  the  temporal  border  of  the  malar 
bone  and  zygoma,  forming  the  outer  boundary 
of  the  temporal  fossa;  the  external  malar  holes, 
the  zygoma  and  its  suture,  which  unites  the 
malar  and  temporal  bones;   the  inferior  or 
masseteric  border  of  the  zygoma,  the  sigmoid 
notch  of  the  lower  jaw  and  the  outer  surface  of 
its  ramus,  coronoid  and  condyloid  processes 
and  angle.    The  deeper  division  of  this  region 
presents  the  large   zygomatic  fossa,   and  is 
situated  internal  to  the  ramus  of  the  jaw,  which 
forms  its  outer  boundary,  and  which  must  be 
removed  to  expose  it  completely  :  this  done, 
the  fossa  is  brought  into  view,  bounded  in 
front  by  the  posterior  surface  of  the  upper  jaw 
and  part  of  the  malar  bone ;  superiorly  by  the 
inferior  surface  of  the  great  wing  of  the  sphe- 
noid below  its  temporal  ridge;  at  this  part  of 
the  fossa  are  seen  the  spheno-tempoval  suture, 
the  spinous  process,  and  the  spinous  and  oval 
foramina  of  the  sphenoid  bone.    The  narrow 
inner  boundary  is  formed  by  the  external  ptery- 
goid plate  of  the  sphenoid  ;  behind  and  below 
the  fossa  is  open.    At  the  bottom  of  the  zygo- 
matic fossa  is  situated  the  pterygo-maxillary 
fissure,   forming  the  external  orifice  of  the 
spheno-maxillary   fossa,   which    is   a  cavity 
situated  between  the  tuberosity  of  the  upper 
jaw  in  front,  and  the  pterygoid  process  and 
palate  bone  behind  :  in  this  fossa  are  five  holes, 
viz.  three  which  open  into  it  from  behind,  the 
foramen  rotundum,  the  vidian  or  pterygoid, 
and  the  pterygo-palatine ;  one  opening  inter- 
nally at  the  upper  part ;  the  spheno-palatine  ; 
one  below,  the  upper  orifice  of  the  posterior 
palatine  canal.    The  zygomatic  fossa  presents 
also  at  its  upper  and  anterior  part,  the  spheno- 
maxillary fissure,  which  is  directed  from  within 
outwards  and  forwards,  and  is  formed  inter- 
nally by  the  orbitar  processes  of  the  palate  and 
upper  maxillary  bones,  externally  by  the  orbitar 
plate  of  the  sphenoid,  atid  at  its  outer  extremity, 
which  is  large,  by  the  malar  bone;  it  forms  a 
communication  between  the  orbit  and  the  zygo- 
matic fossa.  Its  inner  end  joins  the  sphenoidal 
and  the  pterygo-maxillary  fissures,  with  the 
former  of  which  it  forms  an  acute,  and  with 
the  latter,   a  right  angle :   thus  these  three 
fissures  may  be  considered  as  branching  from 
a  common  centre  at  the  back  of  the  orbit;  they 
give  passage  to  a  number  of  vessels  and  nerves, 


and  establish  communications  between  the  cavi. 
ties  of  the  face  and  cranium. 

The  superior  or  cranial  region  is  very  irregu- 
lar, and  is  immoveably  united  to  the  cranium. 
It  presents  along  the  median  line,  from  before 
backwards,  the  articulation  of  the  nasal  bone, 
with  the  nasal  spine  of  the  frontal,  the  union 
of  this  spine  with  the  perpendicular  plate  of 
the  ethmoid,  the  articulation  of  this  plate  with 
the  vomer,  the  articulation  of  the  vomer  with 
the  sphenoid. 

Along  the  sides,  from  within  outwards,  are 
seen  the  arched  roof  of  the  nasal  fossae  formed 
in  front  of  the  nasal  bones,  in  the  middle  by 
the  cribriform  plate  of  the  ethmoid,  and  behind 
by  the  body  of  the  sphenoid.  External  to  these 
parts  are  found  the  base  of  the  pterygoid  process, 
the  articulation  of  the  palate  with  the  body  of 
the  sphenoid  bone,  the  pterygo-palatine  canal, 
the  spheno-palatine  foramen  ;  next  the  spongy 
masses  of  the  ethmoid  united  behind  with  the 
sphenoid,  and  anteriorly  with  the  os  frontis; 
and  still  more  forwards  are  seen  the  articula- 
tions of  this  bone  with  the  lachrymal,  upper 
maxillary,  and  nasal.  To  the  outer  side  of 
these  articulations  is  the  triangular  roof  of  the 
orbit,  limited  externally  by  the  sphenoid  and 
malar  bones  and  by  the  sphenoidal  fissure. 
Next  may  be  observed  the  orbitar  plates  of  the 
sphenoid,  forming  the  greater  part  of  the  outer 
wall  of  the  orbit,  and  lastly  the  zygoma.  The 
inner  border  of  the  orbitar  plate  of  the  frontal 
bone  presents  the  fronto-lachrymal  and  the 
frontal-ethmoidal  sutures  ;  the  outer  border  the 
spheno-frontal  and  fronto-jugal  sutures. 

The  internal  structure  of  the  face  appears 
to  be  very  complex,  presenting  several  cavities 
and  divisions  which  give  it  at  the  same  time 
strength  and  lightness.  The  arrangement  of 
these  parts  may  be  understood  by  observing, 
1.  the  perpendicular  septum  formed  by  the 
ethmoid  and  vomer,  which  divides  the  upper 
part  of  the  face  into  two  equal  halves;  2.  in 
each  half  three  horizontal  divisions,  viz.  an 
upper  or  frontal,  which  separates  the  cranium 
from  the  orbit ;  a  middle  or  maxillary,  placed 
between  the  orbit  and  the  cavity  of  the  nose, 
and  an  inferior  or  palatine  situated  between  the 
nose  and  mouth;  3.  three  outer  divisions,  viz. 
an  upper  or  spheno-jugal,  forming  the  outer 
wall  of  the  orbit,  and  separating  that  cavity 
from  the  temporal  fossa;  a  middle,  formed  by 
the  maxillary  tuberosity  which  separates  the 
cavity  of  the  nose  from  the  spheno-maxillary 
and  zygomatic  fossae ;  an  inferior,  formed  by 
the  ramus  of  the  jaw;  4.  above  and  at  the 
centre  the  ethmoid  and  lachrymal  bones  sepa- 
rate the  orbits  from  each  other  and  from  the 
cavities  of  the  nose. 

The  principal  cavities  of  the  face  are  the 
orbits,  the  nasal  fossae,  and  the  mouth ;  and 
with  these  all  the  rest  are  more  or  less  con- 
nected. These  cavities  will  be  described  under 
the  several  articles,  Orbit,  Nose,  Mouth. 

Mechanism  of  the  face. — The  face  forms  a 
structure  which  combines  both  strength  and 
lightness ;  the  former  quality  is  owing  to  the 
arched  form  of  its  exterior  and  to  the  strong 
pillars  of  supports  (to  be  presently  described) 


213 


FACE. 


which  connect  its  different  parts  to  each  other 
and  to  the  cranium.  The  lightness  of  the  face 
depends  upon  the  thinness  of  some  of  its 
bones,  and  the  large  cavities  which  it  com- 
prises. The  two  upper  maxillary  bones  form 
by  their  alveolar  border  and  palatine  arch  a 
strong  platform,  from  which  ascend  five  osseous 
pillars;  one  median,  formed  by  the  vomer  and 
the  perpendicular  plate  of  the  ethmoid;  two 
at  the  sides  of  the  nose,  formed  by  the  nasal 
process  of  the  superior  maxilla ;  and  at 
the  lateral  parts  of  the  face  two  others, 
formed  by  the  malar  processes  of  the  upper 
jaw  and  the  malar  bones.  All  these  pillars 
connect  the  upper  jaw  with  the  bones  of  the 
cranium,  and  contribute  by  their  form,  strength, 
or  extent  of  articulation  to  resist  or  diffuse  the 
concussion  of  violent  blows  applied  to  the  face. 
The  strength  of  the  lower  jaw  depends  upon 
its  arched  form  and  upon  its  mobility,  but, 
from  its  exposed  situation,  it  is  notwithstand- 
ing frequently  broken. 

Development  of  the  face. — The  development 
of  the  face  consists  not  merely  in  its  general 
increase,  but  in  the  relative  proportion  of  its 
several  parts  at  different  periods  of  life.  As 
the  face  contains  the  organs  of  sight,  smell, 
and  taste,  together  with  those  of  mastication, 
we  shall  not  expect  to  find  it  much  deve- 
loped in  the  foetus  and  infant  while  these 
parts  are  scarcely  called  into  action ;  accord- 
ingly, we  observe  the  vertical  diameter  of  the 
face  (strictly  so  called)  to  be  very  short,  which 
is  owing  to  the  slight  elevation  of  the  ethmoid, 
the  lachrymal,  the  upper  and  the  lower  maxil- 
lary bones,  consequent  on  the  imperfect  deve- 
lopment of  the  nasal  cavities,  the  maxillary 
sinuses,  and  the  teeth;   see  Jig.  131.  The 


Fig.  131. 


orbits,  indeed,  are  remarkably  large,  but  this 
depends  upon  the  great  development  of  the 
cranium  and  the  breadth  of  the  orbitar  plates 
of  the  frontal  bones,  for  in  their  vertical  dia- 
meters the  orbits  are  not  remarkable  at  this 
period  of  life. 

The  transverse  diameter  of  the  face  in  the 
fetus  is  considerable  across  the  orbits,  but 
below  these  it  is  narrower  in  proportion  than  in 
the  adult.  The  other  chief  peculiarities  of  the 
fetal  face  are,  the  small  size  of  the  nasal  cavi- 
ties, the  absence  of  the  canine  fossa?,  depend- 
ing partly  on  the  small  vertical  diameter  of  the 
upper  jaw,  and  partly  upon  the  teeth  being 
still  lodged  withm  it;  the  prominence  and 
shortness  of  the  alveolar  borders  of  both  jaws, 
the  vertical  direction  of  the  symphysis  menti, 
which  even  inclines  from  above  downwards 
and  a  little  backwards;  the  remarkable  con- 


vexity of  the  maxillary  tuberosities,  owing  to 
the  teeth  being  lodged  within  them  ;  and  the 
great  obliquity  from  above  downwards  and 
forwards  of  the  posterior  apertures  of  the  nose, 
arising  from  the  smallness  of  the  maxillary 
sinuses;  the  small  antero-posterior  diameter  of 
the  palatine  arch,  which  depends  upon  the 
same  cause;  and,  finally,  the  oblique  direction 
of  the  rami  of  the  lower  jaw :  see  Jig.  377, 
vol.  i.  p.  742. 

In  the  adult,  as  the  ethmoid  and  turbinated 
bones  together  with  the  maxillary  sinuses 
become  developed,  the  nasal  cavities  enlarge, 
especially  in  their  vertical  diameter;  above, 
they  communicate  with  the  frontal  sinuses, 
which  are  now  fully  formed  and  projecting ; 
the  jaws  have  become  deeper  from  the  protru- 


Fig.  132. 


sion  of  the  teeth,  which  cause  a  considerable 
addition  to  the  vertical  diameter  of  the  face ; 
below,  the  palatine  arch  has  extended  back- 
wards with  the  development  of  the  maxillary 
sinuses,  and  the  posterior  apertures  of  the  nose 
have  become  in  consequence  nearly  vertical : 
the  rami  of  the  lower  jaw  form  also  nearly 
a  right  angle  with  its  body. 

In  old  age  the  vertical  diameter  of  the  face 
decreases  in  consequence  of  the  loss  of  the 
teeth  and  the  contraction  of  the  alveolar  borders 
of  the  jaws,  which  touch  each  other  when  the 
mouth  is  closed;  the  rami  of  the  jaw  resume 
the  oblique  direction  of  childhood,  (Jig.  133;) 


Fig.  133. 


FACE. 


219 


and  the  symphysis  inclines  from  the  shrunken 
alveolar  border  downwards  and  forwards  to  the 
base  of  the  bone,  and  gives  to  the  chin  the 
projecting  appearance  which  is  so  character- 
istic of  this  period  of  life. 

The  art  iculations  of  the  face  comprise  those 
of  the  upper  and  that  of  the  lower  jaw. 

The  articulations  of  the  bones  of  the  upper 
jaw  with  each  other  and  with  those  of  the  cra- 
nium are  all  of  the  kind  called  suture,  but  they 
present  considerable  variety  in  the  extent,  form, 
and  adaptation  of  their  articular  surfaces. 
Those  bones  of  the  face  which  contribute  to 
form  its  columns  of  support,  and  to  which  this 
part  of  the  head  owes  its  strength  and  resistance 
to  violence,  have  their  articular  surfaces  for  the 
most  part  broad  and  rough,  presenting  emi- 
nences and  depressions  which  are  adapted  to 
those  of  the  contiguous  bone;  examples  of  this 
firm  articulation  are  seen,  1.  at  the  anterior 
part  of  the  intermaxillary  suture,  where  the  two 
palatine  plates  unite  and  form  the  horizontal 
column  or  base  of  the  upper  jaw;  2.  at  the 
nasal  columns,  where  the  nasal  bones  and  the 
nasal  processes  of  the  upper  maxillae  unite  with 
the  frontal ;  3.  on  the  sides  of  the  face,  or 
where  the  bones  form  their  lateral  or  malar 
columns,  viz.  at  the  jugo-maxillary  and  jugo- 
frontal  articulations.  The  spheno-jugal  articu- 
lation, seen  within  the  orbit,  and  the  zygomatic 
or  temporo-jugal,  though  formed  by  the  union 
of  comparatively  narrow  surfaces  or  borders, 
derive  strength  from  their  irregularity,  and,  in 
the  case  of  the  zygomatic  suture,  from  its  in- 
dented form,  which  maintains  its  security  from 
vertical  blows,  as  the  curved  direction  of  the 
zygoma  protects  it  from  lateral  injury. 

Those  sutures  of  the  face  which  are,  strictly 
speaking,  harmonic,  are  such  as  are  not  exposed 
to  any  considerable  pressure ;  they  present, 
nevertheless,  some  varieties  in  their  mode  of 
juxta-position.  In  some  the  adaptation  is 
direct,  as  in  the  pterygo-palatine.  In  others 
one  border  or  surface  is  received  by  another 
(schindylesis ),  as  in  the  articulations  of  the 
vomer  with  the  sphenoid  above,  and  with  the 
groove  in  the  palatine  plates  of  the  upper  max- 
illary and  palate  bone  inferiorly.  Sometimes 
the  surfaces  are  simply  applied  against  each 
other,  as  the  nasal  plate  of  the  palate  bone  on 
the  nasal  surface  of  the  upper  maxillary. 
Lastly,  the  edges  may  alternately  overlap  each 
other,  as  those  of  the  nasal  and  upper  maxillary 
bones. 

In  all  the  sutures  of  the  face,  whatever  may 
be  the  adaptation  of  the  osseous  surfaces,  we 
find  interposed  a  thin  layer  of  cartilage  uniting 
the  contiguous  surfaces  of  the  bones.  This  is 
easily  shown  in  some  of  the  sutures  by  mace- 
ration, and  only  disappears  in  places  as  some 
of  the  bones  become  united  with  advancing 
age. 

The  great  number  of  pieces  of  which  the 
upper  jaw  consists,  and  the  varying  form  and 
direction  of  the  sutures,  all  contribute,  with  the 
figure  of  the  bones  themselves,  to  give  strength 
to  this  part  of  the  skull,  and  to  break  the  force 
of  blows  by  diffusing  them  over-  a  widely  ex- 
tended surface. 


The  sutures  of  the  face  derive  their  names 
from  the  bones  which  contribute  to  form  them; 
thus  we  have  between  the  orbits  the  fronto- 
nasal, fronto-maxillary,  and  fronto-lachrymal 
sutures,  all  contributing  to  form  part  of  the 
transverse  suture.  (See  Cranium.)  Lower 
down  we  find  the  nasal,  the  naso-maxillary, 
and  the  laehrymo-maxillary,  which  turns  at 
right  angles  backwards  along  the  inner  wall  of 
the  orbit  into  the  ethmoido-maxillary  and  pa- 
lato-orbitar  sutures.  On  the  outer  side  of  the 
orbit  may  be  observed  the  frorito-jugal  and 
spheno-jugal  sutures  ;  on  the  zygomatic  arch 
the  temporo-jugal  suture;  and  below  the  pro- 
minence of  the  cheek,  the  jugo-maxillary 
suture,  which  is  seen  both  on  the  anterior  and 
posterior  surface  of  the  upper  jaw.  On  the 
roof  of  the  mouth  are  seen  the  longitudinal  and 
the  transverse  palatine  sutures,  the  former 
formed  by  the  intermaxillary  in  front,  and  by 
the  inter-palatine  suture  behind  :  the  latter  is 
often  termed  the  transverse  or  horizontal  palato- 
maxillary suture.  There  are  some  other  sutures 
within  the  nose  which  it  is  unnecessary  to  enu- 
merate. 

The  lower  jaw  articulates  with  the  cranium 
by  diarthrosis :  this  important  joint  will  be 
particularly  described  in  the  article  Temporo- 

MAXILLAKY  ARTICULATION. 

The  bones  of  the  face  are  invested  with 
periosteum  or  a  fibrous  membrane,  which  is 
variously  modified  and  arranged  in  the  orbits, 
nose  and  mouth,  &c. 

ABNORMAL  CONDITIONS  OF  THE  BONES  OF 
THE  FACE. 

In  the  true  acephalous  foetus  the  bones 
of  the  face  as  well  as  those  of  the  cranium 
are  of  course  wanting,  but  the  former  are 
generally  found  in  what  are  termed  the  false 
Acephalia  (see  Abnormal  Conditions  of 
the  Cranium)  ;  it  sometimes  happens,  not- 
withstanding, that  the  bones  of  the  face  are  but 
imperfectly  developed,  presenting  a  variety  of 
conformations  which  it  is  unnecessary  to  parti- 
cularise. The  bones  of  the  face,  in  some  cases 
alone,  and  in  others  in  conjunction  with  those 
of  the  cranium,  not  unfrequently  acquire  a  de- 
gree of  development  quite  disproportionate  with 
the  rest  of  the  skeleton.  In  Corvisart's  Journal 
de  Medecine  the  case  of  a  Moor  is  cited,  whose 
head  and  face  were  so  enormous  that  he  could 
not  stir  abroad  without  being  followed  by  the 
populace.  It  is  related  that  the  nose  of  this 
man,  who  was  half  an  idiot,  was  four  inches 
long,  and  his  mouth  so  large  that  he  would  bite 
a  melon  in  the  proportion  that  an  ordinary  per- 
son would  eat  an  apple.  I  have  now  before 
me  the  skull  of  a  native  of  Shields,  who  was 
remarkable  during  life  for  the  length  of  his 
face  ;  the  entire  head  is  large,  but  the  bones  of 
the  face,  and  particularly  the  lower  jaw,  are 
enormously  long.  The  abnormal  development 
of  the  facial  bones  generally  affects  one  jaw 
only,  and  more  frequently  the  lower,  as  in  the 
example  just  mentioned.  Othercases,  but  they 
are  much  more  rare,  have  been  related  in 
which  the  lower  jaw  was  disproportionately 
small.    When,  from  either  of  the  circumstances 


220 


FACE. 


which  have  been  just  mentioned,  the  develop- 
ment of  the  two  jaws  is  unequal,  the  corre- 
spondence of  their  alveolar  borders  is  lost,  and 
mastication  becomes  in  proportion  imperfect : 
in  mammiferous  animals  the  unequal  size  of 
the  lower  jaw,  by  preventing  suckling,  is  often 
a  cause  of  death.  The  bones  of  the  face  are 
much  more  symmetrical  than  those  of  the  cra- 
nium, and  rarely  present  the  disproportion  in 
their  lateral  development  which  is  observed  in 
the  latter. 

Under  the  head  of  defect  or  arrest  of  deve- 
lopment may  be  noticed,  1.  the  occasional  ab- 
sence of  some  of  the  bones,  as  for  example,  the 
lachrymal  or  the  vomer;  2.  the  existence  of 
fissures,  or  non-union  of  the  upper  maxillary 
bones,  and,  as  a  more  rare  case,  the  separation 
of  the  two  halves  of  the  lower  jaw.  Fissures 
of  the  upper  jaw  may  exist  in  various  degrees, 
and  may  occur  with  or  without  a  corresponding 
cleft  in  the  soft  palate  and  lip  ;  it  may  appear 
as  a  mere  slit  along  the  middle  of  the  roof  of 
the  mouth,  forming  a  narrow  communication 
between  that  cavity  and  one  side  of  the  nose ; 
or  it  may  extend  along  the  whole  of  the  pala- 
tine arch,  and  be  continuous  behind  with  a 
similar  division  of  the  soft  palate,  without,  at 
the  same  time,  being  accompanied  with  hare- 
lip. Sometimes  the  aperture  is  very  wide,  and 
the  palatine  plates  of  the  upper  maxillary  and 
palate  bones  are  almost  entirely  wanting ;  in 
this  case  the  vomer  and  middle  cartilage  of  the 
nose  are  also  partially  or  entirely  absent;  and 
there  is  both  hare-Hp  and  cleft  of  the  soft 
palate,  so  that  the  mouth,  both  sides  of  the 
nose,  and  the  pharynx  are  laid  into  one  great 
cavity.  When  the  fissure  exists  at  the  anterior 
part  of  the  palate  only,  it  almost  invariably 
occurs  at  the  suture  which  has  been  described 
between  the  maxillary  and  intermaxillary  bones, 
so  that  the  cleft  separates  the  canine  from  the 
lateral  incisor  tooth  ;  when  the  fissure  occurs 
on  both  sides  of  the  face,  the  four  incisor  teeth 
are  separated  from  the  others  and  lodged  in  an 
alveolar  border,  which  usually  in  this  case 
projects  more  or  less  towards  the  lip,  in  which 
there  is  also  commonly  a  single  or  double  cleft 
or  hare-lip.  Sometimes  the  fissure  occurs  in 
the  intermaxillary  bone  itself  between  the  lateral 
and  middle  incisor  teeth,  and  then  we  find  a 
single  incisor  on  one  side  and  three  on  the  op- 
posite :  it  is  very  rarely  that  the  cleft  exists  in 
the  median  line  between  the  two  intermaxillary 
bones. 

Among  the  arrests  of  development  which 
occur  in  the  bones  of  the  face  may  be  enume- 
rated a  fissure  which  occasionally  extends 
across  the  lower  border  of  the  orbit,  and  a 
suture  which  sometimes  divides  the  os  jugum 
into  two  pieces. 

The  union  which  not  unfrequently  takes 
place  between  the  bones  of  the  upper  jaw  by 
the  obliteration  of  their  sutures,  is  commonly 
the  effect  of  age,  and  usually  occurs  between 
the  bones  of  the  nose,  between  the  vomer  and 
sphenoid,  and  between  the  inferior  turbinated 
and  upper  maxillary  bones.  Wounds  and  frac- 
tures of  the  bones  of  the  face  readily  unite. 
Those  most  subject  to  these  injuries  are  such 


as  are  the  most  prominent,  viz.  those  of  the 
nose,  cheek,  and  lower  jaw  ;  the  last  is  the 
most  frequently  broken.  The  alveolar  pro- 
cesses and  the  delicate  bones  in  the  orbit  and 
nose  are  also  liable  to  injury.  The  bones  of 
the  face  are  subject,  like  the  rest,  (though  not 
so  commonly  as  those  of  the  cranium,)  to  hy- 
pertrophy and  atrophy.  Exostosis  appears  most 
frequently  on  the  upper  jaw,  in  the  orbit,  or 
along  the  alveolar  border  on  the  outer  surface 
of  the  bones ;  on  the  lower  jaw  it  is  situated 
usually  along  the  alveolar  border,  at  the  angle 
or  on  the  body  of  the  bone.  Inflammation  of 
the  periosteum  and  bones  of  the  face  occurs 
spontaneously  or  as  the  result  of  injuries  or 
disease,  and  presents  the  usual  phenomena. 
Abscesses  also  take  place  either  within  the 
cancellous  structure  of  the  more  solid  bones, 
or  in  the  cavities  which  they  contain  ;  when 
matter  forms  within  the  antrum,  it  may  be 
evacuated  by  extracting  the  canine  or  the  large 
molar  tooth,  which  often  projects  into  this  ca- 
vity, and  then  piercing  through  the  bottom  of 
their  sockets.  When  necrosis  affects  the  bones 
of  the  face,  its  ravages  are  seldom  repaired  (as 
in  the  case  of  cylindrical  bones)  by  the  pro- 
duction of  new  osseous  matter  ;  some  attempts 
at  reparation  after  the  separation  of  a  seques- 
trum have  been,  however,  observed  in  the  lower 
jaw.  Caries,  either  simple  or  connected  with 
syphilitic  or  strumous  disease,  may  attack 
nearly  all  the  bones  of  the  face,  but  it  more 
particularly  affects  the  alveolar  borders  of  the 
jaws  and  the  delicate  bones  about  the  nose  and 
palate ;  it  is  often  attended  with  partial  ne- 
crosis. Caries  of  the  face  may  occur  as  the  re- 
sult of  malignant  ulcerations,  of  lupus,  or  of  the 
various  forms  of  cancer  which  affect  the  soft 
parts.  Both  the  upper  and  lower  jaw  are  sub- 
ject to  osteosarcoma,  commencing  either  on  the 
surface  or  in  the  interior  of  the  bones,  and  ac- 
quiring sometimes  an  enormous  size,  so  as  to 
encroach  on  the  orbit,  nose,  and  mouth,  and 
materially  to  impede  the  motions  of  the  lower 
jaw.  For  these  growths  and  others  more  sim- 
ple, of  a  fibrous  or  fibrocartilaginous  structure, 
large  portions  (sometimes  amounting  to  nearly 
the  whole)  of  the  upper  or  lower  jaw  have  been 
removed  with  success.  Cyst-like  tumours,  con- 
taining a  serous  fluid,  have  been  found  in  the 
lower  jaw.  The  more  intractable  diseases  of 
medullary  sarcoma  undjungous  growths  of  va- 
rious kinds  also  attack  the  bones  of  the  face. 
A  few  cases  of  hydatids  (the  acephalo-cystus) 
have  been  met  with  in  the  upper  jaw. 

THE  MUSCLES  OF  THE  FACE 

are  arranged  around  the  orifices  of  the  eyelids, 
the  nose,  and  the  mouth,  and  may  be  divided 
into  constrictors  and  dilators  of  these  apertures. 
The  nostrils,  however,  undergo  but  little  vari- 
ation in  their  dimensions,  being  maintained 
permanently  open  by  the  elastic  cartilages 
which  form  them.  The  eyelids  also  contain 
elastic  cartilages,  which  are  moulded  upon 
the  front  of  the  globe  over  which  they  glide  in 
obedience  to  the  muscles  which  dilate  or  con- 
tract the  orifice  between  them.  The  mouth, 
which  is  the  most  mobile  of  the  facial  aper- 


FACE. 


tures,  is  also  furnished  with  its  contractor  or 
sphincter  muscle,  and  with  many  dilators 
which  radiate  from  it  at  various  angles. 

All  the  muscles  of  the  face  are  superficially 
situated,  and  most  of  them  are  subcutaneous. 

In  the  palpebral  regions,  or  about  the  eye- 
lids on  each  side,  are  placed,  1.  a  constrictor, 
or  the  orbicularis  palpebrarum,  of  which  the 
corrugator  supercilii  is  an  associate;  2.  the 
levator  palpebral  and  the  occipito-frontalis, 
which  are  dilators,  and  antagonists  of  the  two 
former  muscles. 

The  orbicularis  palpebrarum, (naso-pulpebral, 
Chauss.)  is  a  flat  oval  muscle,  situated  im- 
mediately underneath  the  skin,  to  which  it 
adheres,  and  covering  the  base  of  the  orbit 
and  the  superficial  surface  of  the  eyelids ;  in 
the  middle  it  presents  a  transverse  aperture, 
which  is  the  orifice  of  the  palpebral,  varying 
in  size  according  to  the  individual,  and  giving 
apparently  a  greater  or  less  magnitude  to  the 
globe  itself,  which,  however,  is  of  nearly  uni- 
form dimensions  in  different  persons.  The 
orbicularis,  like  the  other  sphincter  muscles, 
consists  of  concentric  fibres,  but  it  is  peculiar 
in  having  a  fixed  tendon  on  one  side,  from 
which  a  great  part  of  the  fibres  arise ;  this 
tendon  of  the  orbicularis,  or  ligamentum  pal- 
pebrae,  which  is  situated  horizontally  at  the 
inner  corner  of  the  eye,  is  about  two  and  a 
half  lines  in  length,  and  half  a  line  in  breadth; 
it  arises  from  the  anterior  border  of  the  lachry- 
mal groove  in  the  nasal  process  of  the  upper 
maxillary  bone,  and  passing  horizontally  out- 
wards in  front  of  the  lachrymal  sac,  divides 
into  a  superior  and  an  inferior  slip,  which  are 
attached  to  the  inner  extremities  of  the  corres- 
ponding eyelids.  The  tendon  at  first  is  flat- 
tened anteriorly  and  posteriorly,  but  afterwards 
becomes  twisted  so  as  to  present  horizontal 
surfaces.  From  its  posterior  part  is  detached 
a  slip  of  fibres  (the  reflected  tendon  of  the 
orbicularis),  which  proceeds  backwards  to- 
wards the  os  unguis,  and  forms  the  outer  wall 
of  the  lachrymal  canal. 

The  orbicularis  arises,  1.  from  the  borders 
and  surfaces  of  this  tendon  and  from  its 
reflected  slip  ;  2.  from  the  internal  angular 
process  of  the  frontal  bone  and  from  the  fronto- 
maxillary  suture  ;  3.  from  the  nasal  process  of 
the  upper  maxillary  bone  ;  and,  4.  by  short 
tendinous  slips  from  the  inner  third  of  the  lower 
border  of  the  orbit.  From  these  origins  the 
upper  and  lower  fibres  of  the  muscle  take  a 
curved  direction  outwards,  their  concavity  look- 
ing towards  the  aperture  of  the  lids,  and  fol- 
lowing the  course  of  the  upper  and  lower 
borders  of  the  orbit,  which  they  overlap. 
They  unite  at  the  outer  side ;  not,  however,  by 
a  tendinous  raphe  or  septum,  as  some  have 
described,  but  simply  by  the  mingling  of  their 
fibres.  Each  half  (the  upper  and  lower)  of 
the  orbicularis  consists  really  of  two  sets  of 
fibres ;  one,  which  covers  the  margins  of  the 
orbits,  and  forms  the  circumference  of  the 
muscles,  is  strong,  tense,  and  of  the  usual 
reddish  colour ;  it  arises  from  the  direct  ten- 
don, and  from  the  frontal  or  upper  maxillary 
bone.    These  form  the  orbicularis  properly  so 


called.  The  other  set,  which  is  pale  and  thin, 
covers  the  lids  and  proceeds  almost  in  a  hori- 
zontal direction  outwards  from  the  palpebral 
bifurcation  of  the  orbicular  tendon  :  this  forms 
the  ciliary  or  palpebrales.  These  two  sets  of 
fibres,  as  we  shall  presently  see,  are  distin- 
guished as  much  by  their  functions  as  by  their 
appearance. 

Relations. — The  superficial  surface  of  that 
part  of  the  muscle  which  covers  the  lids 
(the  palpebrales)  is  connected  to  the  skin  by 
delicate  loose  cellular  tissue  entirely  destitute 
of  fat.  The  stronger  fibres  which  form  the 
outer  part  of  the  muscles  are  closely  adherent 
to  the  integument  by  cellular  tissue  more 
densely  woven,  and  presenting  more  or  less 
fat.  The  posterior  surface  covers,  above,  the 
lower  part  of  the  frontalis  and  the  corrugator 
supercilii,  with  whose  fibres  it  is  connected  ; 
internally  the  corresponding  part  of  the  fibro- 
cartilages  of  the  lids,  the  lachrymal  sac,  and 
the  inner  border  of  the  orbit  externally,  the 
outer  border  of  the  orbit  and  part  of  the  tem- 
poral fascia  inferiorly,  the  upper  part  of  the 
malar  bone,  the  origins  of  the  levator  labii 
superioris  proprius,  the  part  of  the  levator 
labii  superioris  alaeque  nasi,  and  the  inferior 
border  of  the  orbit.  At  its  circumference  this 
muscle  corresponds,  by  its  upper  half,  to  the 
frontal,  which  it  slightly  overlaps,  and  inter- 
nally to  the  border  of  the  pyramidalis,  with 
which  it  is  connected ;  externally  it  is  free. 
Below  its  border  is  free,  covering  the  origin, 
and  giving  some  fibres  to  the  lesser  zygomatic  ; 
and  internally  it  is  separated  from  the  levator 
labii  superioris  alaeque  nasi  by  cellular  tissue, 
in  which  runs  the  facial  vein.  The  central 
fibres  cover  the  palpebral  fascia  and  the  lids, 
which  separate  them  from  the  conjunctiva. 

Action. — The  action  of  this  muscle  resem- 
bles that  of  other  sphincters,  the  curved  fibres 
in  contraction  approaching  the  centre ;  but  as 
in  the  orbicularis  palpebrarum  these  fibres  are 
fixed  at  the  inner  side,  it  follows  that  the  skin 
to  which  the  muscle  is  attached  by  its  anterior 
surface  is  drawn  towards  the  nose,  and  when 
the  muscle  is  in  strong  action,  becomes  cor- 
rugated, presenting  folds  which  converge  to- 
wards the  inner  angle  of  the  eye ;  above,  where 
the  effect  of  the  muscle  on  the  skin  is  most 
marked  in  consequence  of  its  closer  connec- 
tion with  the  integuments,  the  brow  and  the 
skin  of  the  forehead  are  drawn  down  by  it 
and  its  associate  the  corrugator;  the  lower 
fibres  when  in  strong  action,  draw  the  cheeks 
upwards  and  inwards.  Like  the  other  sphinc- 
ters, also,  this  is  a  mixed  muscle.  Those 
fibres  which  may  be  supposed  to  be  voluntary, 
are  the  larger  and  outer  ones,  which  corres- 
pond to  the  border  of  the  orbit,  and  are  of  a 
red  colour.  The  involuntary  fibres  are  those 
thin  ones  which  cover  the  lids,  are  of  a  pale 
colour,  like  the  muscles  of  organic  life,  and 
arise  from  the  palpebral  subdivisions  of  the 
horizontal  tendon.  They  contract  involuntarily 
while  we  are  awake,  in  the  action  of  winking, 
and  during  sleep  in  maintaining  the  lids  closed; 
they  also  act  under  the  will  in  closing  the 
lids,  particularly  the  upper.    It  appears  then 


225 


FACE. 


that  the  orbicularis  may  be  divided  both  ana- 
tomically and  physiologically  into  two  sets  of 
fibres;  an  outer,  or  orbicularis  proper,  which  is 
entirely  a  voluntary  muscle,  and  an  inner 
(the  palpebrals)  which  is  both  voluntary  and 
involuntary  in  its  action.  These  fibres  may 
act  independently  of  each  other,  for  in  wink- 
ing and  during  sleep  the  palpebralis  contracts, 
while  the  orbicularis  is  quiescent ;  and  the 
orbicularis  may  contract  even  strongly,  as  when 
we  peer  with  the  eyes  under  the  influence  of  a 
strong  light,  while  the  fibres  of  the  pal- 
pebrals are  relaxed.  It  has  been  supposed, 
however,  by  some,  that  during  sleep  the  lid 
is  closed  simply  by  the  weight  of  the  upper 
palpebra,  and  the  relaxation  of  its  proper 
elevator  muscle,  but  this  seems  in  contra- 
diction to  the  fact  that  we  meet  with  resistance 
in  endeavouring  to  unclose  the  lids  of  a  sleep- 
ing person. 

Corrugator  supercilii,  which  is  the  associate 
of  the  orbicularis  palpebrarum,  has  been  al- 
ready described,  together  with  the  occipito- 
frontalis,  which  is  the  antagonist  of  those 
muscles.  See  Cranium,  muscles  of  the, 
vol.  i.  p.  747. 

Levator  palpebra  superioris  (  orbito-palpe- 
bral ),  though  situated  within  the  orbit,  is 
nevertheless  the  direct  antagonist  of  the  palbe- 
bralis,  and  is  therefore  properly  described  with 
these  muscles  of  the  face.  It  is  a  thin  trian- 
gular muscle,  which  arises  by  a  narrow  slen- 
der tendon  at  the  back  of  the  orbit  from  the 
inferior  surface  of  the  lesser  wing  of  the  sphe- 
noid bone,  above  and  in  front  of  the  optic 
foramen  ;  from  this  origin  the  fibres  proceed 
almost  horizontally  forwards  under  the  roof  of 
the  orbit,  and  gradually  spreading  and  be- 
coming thinner  as  they  advance,  curve  over 
the  globe  of  the  eye,  and  are  inserted  into  the 
upper  border  and  anterior  surface  of  the  upper 
lid. 

Relations. — Its  upper  surface  is  in  contact, 
behind,  with  the  frontal  branch  of  the  ophthal- 
mic nerve,  which  with  some  cellular  tissue 
alone  separates  it  from  the  periosteum  of  the 
roof  of  the  orbit ;  anteriorly  with  cellular  tissue 
and  the  palpebral  fascia,  which  separate  it  from 
the  orbicularis.  The  lower  surface  behind  rests 
upon  the  superior  rectus  oculi,  with  which  it 
is  connected  by  cellular  tissue,  and  anteriorly 
on  the  conjunctiva  and  upper  lid. 

Its  action  is  to  raise  the  upper  lid,  and  to 
draw  it  backwards  over  the  globe  and  under 
the  supra-ciliary  ridge.  There  is  no  separate 
muscle  to  effect  the  depression  of  the  lower 
lid,  that  action  being  occasioned,  as  Sir  C. 
Bell  ingeniously  suggested,  by  the  protrusion 
of  the  eyeball. 

Nasal  region. — The  muscles  of  this  region, 
some  of  which  are  common  to  the  upper  lip, 
are,  1.  the  pyramidalis ;  2.  the  levator  labii 
superioris  alaque  nasi;  3.  the  triangularis 
nasi;  4.  the  depressor  ala  nasi. 

Pyramidalis  is  situated  between  the  brows, 
and  may  be  considered  as  a  prolongation  of 
the  inner  fibres  of  the  frontalis :  it  is  of  a 
triangular  form  ;  its  base  above  is  continuous 
with  the  fibres  of  the  frontalis;  below  it  con- 


tracts and  is  inserted  into  the  aponeurotic  ex- 
pansion of  the  triangularis  nasi.  It  is  sepa- 
rated from  its  fellow  slip  of  the  opposite  side 
by  a  groove  of  cellular  tissue. 

Relations. —  Its  superficial  surface  adheres 
to  the  skin ;  its  deep  one  rests  on  the  nasal 
eminence  of  the  frontal  bone,  the  nasal  bones, 
and  part  of  the  lateral  cartilage  of  the  nose. 

Use. — If  this  muscle  acts  at  all  on  the  nose, 
it  is  by  drawing  up  the  skin  when  the  occipito- 
frontaiis  is  in  action.  Its  more  probable  use 
is  to  give  a  fixed  point  to  the  frontalis,  and  to 
draw  down  the  inner  extremity  of  the  brows 
and  the  skin  between  them. 

Levator  labii  superioris  alaque  nasi. — (I', 
fig.  134.)     This  is  a  thin,   long,  triangular 


Fig.  134. 


muscle,  placed  nearly  vertically  on  each  side 
of  the  nose.  It  arises  narrow  from  the  outer 
surface  of  the  nasal  process  of  the  upper  max- 
illary bone,  immediately  beneath  the  tendon 
of  the  orbicularis  palpebrarum.  It  descends 
obliquely  outwards,  becoming  broader,  and 
terminates  inferiorly  by  two  slips,  an  internal 
short  one,  which  is  attached  to  the  cartilage 
of  the  ala  nasi,  or  to  the  fibrous  membrane 
which  invests  it ;  and  an  outer  longer  slip, 
which  is  attached  to  the  skin  of  the  upper  lip 
near  the  nose,  and  mingles  its  fibres  with  the 
transversalis  nasi,  the  levator  labii  superioris 
proprius,  and  the  orbicularis  oris. 

Relations. — Covered  by  the  skin,  and  over- 
lapped a  little  above  by  the  orbicularis  pal- 
pebrarum, this  muscle  covers  the  nasal  process 
of  the  upper  maxillary  bone,  the  triangularis 
nasi,  and  the  depressor  ala  nasi.  Its  inner 
border  above  corresponds  to  the  pyramidalis. 

Its  action  is  to  raise  the  ala  of  the  nose  and 
the  adjacent  part  of  the  upper  lip;  in  so  doing 
it  dilates  also  the  nostril  and  becomes  a  muscle 
of  inspiration.  When  strongly  thrown  into 
action,  it  corrugates  the  skin  of  the  nose  trans- 
versely. 


FACE. 


223 


Triangularis  nasi  ( transversalis  nasi,  com* 
pressor  naris,  Albin.)  ( n,  fig.  134),  is  a  very 
thin  triangular  muscle,  placed  transversely  on 
the  middle  of  the  side  of  the  nose.  To  expose 
its  origin,  the  levators  of  the  upper  lip  must 
be  turned  aside,  and  the  skin  of  the  nose  very 
carefully  dissected  off'.  Its  origin  is  then  seen 
as  a  narrow  slip  from  the  inner  part  of  the 
canine  fossa,  below  the  ala  nasi ;  from  this 
point  the  fibres  radiate  inwards  and  upwards, 
and  expand  into  a  very  thin  aponeurosis, 
which  crosses  the  ala  nasi  and  the  lateral  car- 
tilage of  the  nose  to  be  confounded  along  the 
median  line  with  that  of  the  opposite  muscle, 
and  with  the  pyramidalis.  Bourgery  describes 
two  other  origins,  one  superficial,  attached  to 
the  skin  below  and  to  the  outside  of  the  ala 
nasi,  and  a  middle  one  crossing  and  connected 
with  the  fibres  of  the  levator  of  the  upper  lip. 

Relations. — It  is  covered  at  its  origin  by  the 
levator  labii  superioris  alreque  nasi,  and  inter- 
nally by  the  integuments  to  which  it  super- 
ficially adheres ;  it  rests  on  part  of  the  upper 
jaw,  on  the  cartilages  of  the  ala,  and  on  the 
lateral  cartilage. 

Its  action  is  yet  undetermined  by  anato- 
mists, some  considering  it  a  compressor  or 
constrictor  of  the  nose,  others  as  a  dilator  or 
elevator.  Cruveilhier  thinks  that  its  action 
varies  with  the  form  of  the  ala,  which,  when 
convex,  makes  it  a  compressor,  when  concave 
a  dilator.  Perhaps,  as  M.  Bourgery  suggests, 
its  action  depends  upon  which  extremity  is 
fixed,  and  that,  when  its  base  is  fixed,  its 
superficial  fibres  dilate  the  nostrils  and  draw 
the  lip  upwards  and  inwards,  and  that,  when 
the  muscle  acts  towards  its  maxillary  attach- 
ment, it  compresses  the  nostril. 

Depressor  ala  nasi  ( musculus  myrtiformis ), 
(fig.  134.)  To  expose  this  muscle  the  upper 
lip  should  be  reversed,  and  the  mucous  mem- 
brane divided  on  each  side  of  the  franum  labii. 
It  is  a  short  flat  muscle,  radiating  upwards 
from  the  myrtiform  fossa  of  the  upper  jaw, 
where  it  arises  towards  the  ala  of  the  nose, 
into  the  posterior  part  of  which  it  is  inserted 
below  and  internal  to  the  dilator  nasi.  This 
muscle  really  consists  of  two  sets  of  fibres, 
one  which  has  been  just  described,  the  other 
which  is  in  front  of  this  and  is  attached  above 
to  the  ala  and  septum  of  the  nose,  below  to 
the  inner  surface  of  the  orbicular  fibres.  The 
first  set,  or  the  naso-maxillary  fibres,  are  de- 
pressors of  the  alae  and  contractors  of  the 
nostrils ;  the  second,  or  naso-labial  fibres,  are 
elevators  of  the  upper  lip. 

Relations. — It  is  covered  by  the  mucous 
membrane  of  the  upper  lip,  by  the  orbicularis 
oris,  and  by  the  levator  labii  superioris  alseque 
nasi ;  it  covers  the  myrtiform  fossa  of  the 
upper  jaw  :  its  inner  border  is  separated  from 
its  fellow  by  the  franum. 

A  dilator  ala  nasi  is  described  by  Bourgery 
as  a  little  triangular  muscle,  consisting  of 
fibres  placed  underneath  the  skin  lying  on  the 
outside  of  the  ala  nasi,  from  the  posterior  part 
of  whose  cartilages  the  fibres  arise  by  a  narrow 
point,  and  then  radiate  upwards,  outwards, 


Fig.  135. 


and  downwards,  to  be  mingled  with  the  fibres 
of  the  elevators  of  the  lip,  the  orbicularis,  and 
the  naso-labial,  all  being  attached  to  the  skin. 
This  muscle,  ^according  to  Bourgery,  directly 
draws  the  ala  outwards,  and  is  consequently  a 
dilator  of  the  nostril. 

The  labial  region  presents  in  the  centre,  1. 
a  sphincter  (the  orbicularis  oris),  with  which 
are  associated  two  muscles  on  each  side,  the 
depressor  labii  superioris  and  the  levator  labii 
inferioris :  all  these  are  contractors  or  com- 
pressors of  the  lips :  2.  a  number  of  anta- 
gonist muscles  or  dilators,  which  comprise 
many  muscles,  which  on  each  side  radiate 
from  the  lips,  or  from  their  commissure  at 
different  angles.  They  are,  above,  the  levator 
labii  superioris  proprius  and  the  zygomaticus 
minor;  below,  the  depressor  labii  inferioris  at 
the  commissure,  the  buccinator,  the  levator 
anguli  oris,  and  the  depressor  anguli  oris.  By 
some  anatomists  the  muscles  of  this  region  of 
the  face  are  divided  into,  1.  the  sphincter, 
and,  2.  the  elevators  and  depressors  of  the 
lips. 

Orbicularis  or  sphincter  oris  (labial,Chauss. 
and  Dum.)  (o  o,  fig.  134)  is  a  thick  oval 
muscle,  placed  transversely  around  the  aper- 
ture of  the  mouth,  which  varies  in  «ize  in  dif- 
ferent persons,  but  bears  no  relation  to  the  size 
of  the  buccal  cavity.  It  extends  above  from 
the  free  border  of  the  upper  lip  to  the  nostrils, 
and  inferiorly  from  the  free  border  of  the  lower 
lip  to  the  depression  above  the  chin.  Its 
fibres,  arranged  in  successive  layers,  consist 
of  two  semi-elliptical  halves,  one  superior,  the 
other  inferior,  which  are  on  each  side  united 
externally  to  the  commissure  of  the  lips  by 
decussating  each  other,  and  mingle  also  at 
their  circumference  with  the  dilators  which  are 
attached  to  it.  These  fibres  are  concentric, 
with  their  curve  towards  the  lips ;  the  most 
central  run  nearly  in  a  horizontal  direction 
along  the  borders  of  the  lips,  and  take  a  di- 
rection forwards,  which  gives  the  prominence 
to  the  lips  which  is  so  remarkable  in  the 
Negro.  The  outer  fibres  are  more  curved, 
and  receive  between  their  layers  the  extensors 
of  the  lips,  which  are  attached  around  them. 
This  is  the  only  muscle  of  the  face  which  has 
no  attachment  to  bone. 

Relations. — The  anterior  surface  is  closely 


224 


FACE. 


connected  with  the  thick  skin  which  covers  it. 
The  posterior  surface  and  free  border  is  covered 
with  the  mucous  membrane  of  the  mouth,  from 
which  it  is  only  separated  in  places  by  the 
labial  glands,  by  the  coronary  vessels,  and  by 
numerous  nerves.  Its  outer  border  or  circum- 
ference receives  the  antagonist  muscles  which 
are  attached  around  it. 

Actions. — The  orbicularis  enjoys  a  very  va- 
ried and  extensive  motion,  and  possesses  the 
remarkable  power  of  either  acting  as  a  whole 
or  in  parts.  Its  simple  use  is  to  close  the 
mouth,  in  correspondence  with  the  elevation 
of  the  lower  jaw,  by  bringing  the  red  borders 
of  the  lips  in  contact,  or  by  pressing  them  to- 
gether firmly.  But  the  upper  or  lower  labial 
fibres  can  act  separately,  or  the  fibres  at  either 
commissure,  or  the  fibres  of  one  side  may  con- 
tract, while  the  others  are  quiescent,  so  that 
different  parts  of  the  lips  may  be  moved  by 
different  portions  of  the  muscle,  which  is  made 
in  this  way  to  antagonize  in  turn  the  different 
muscles  which  are  attached  around. 

The  lips  may  be  thrown  forward  by  the  con- 
traction of  the  labial  and  commissural  fibres 
forming  in  strong  action  a  circular  projection, 
as  in  the  action  of  whistling,  or,  when  more 
relaxed,  in  blowing.  By  the  contraction  of  the 
inner  labial  fibres  the  lips  may,  on  the  contrary, 
be  turned  inwards  so  as  to  cover  the  teeth.  The 
play  of  the  mouth,  however,  which  contributes 
in  so  eminent  a  degree  to  the  expression  of  the 
face,  depends  not  only  on  the  orbicularis,  but 
upon  its  association  with  the  different  muscles 
which  are  attached  around  it. 

Naso-labialis  is  a  small  subcutaneous  slip  of 
fibres,  only  distinctly  seen  in  strong  muscular 
lips.  It  is  situated  on  each  side  of  the  median 
depression  of  the  upper  lip,  and  arises  from 
the  lower  septum  of  the  nose  at  the  back  part 
of  the  nostril ;  it  proceeds  downwards  and  out- 
wards, and  is  soon  lost  in  the  fibres  of  the  or- 
bicularis. It  is  an  elevator  of  the  middle  part 
of  the  upper  lip,  and  is  considered  by  some  as 
an  attachment  of  the  orbicularis. 

Levator  labii  superioris  (I',  Jig.  134)  is  a 
thin,  flat,  quadrilateral  muscle,  situated  about 
the  middle  of  the  face,  and  nearly  on  the  same 
plane  with  the  levator  labii  superioris  alaeque 
nasi.  It  arises  from  the  malar  and  upper 
maxillary  bones  where  they  form  three-fourths 
of  the  lower  border  of  the  orbit,  by  short  ten- 
dinous slips  ;  from  this  origin  the  fibres,  con- 
verging a  little,  take  a  direction  downwards 
and  inwards,  and  are  inserted  partly  super- 
ficially into  the  skin  of  the  upper  lip,  and 
partly  into  the  fibres  of  the  orbicularis,  between 
the  insertion  of  the  levator  labii  superioris 
alaque  nasi  and  the  lesser  zygomatic,  with 
which  its  fibres  are  partly  covered  and  con- 
founded. 

Relations. — Its  anterior  surface  is  covered 
above  by  the  orbicularis  palpebrarum,  below 
by  the  skin  and  by  the  muscles  with  which  its 
fibres  are  mingled  at  its  insertion.  Its  posterior 
surface  covers  the  infra-orbitar  vessels  and 
nerves  at  their  exit  from  the  infra-orbitar  fo- 
ramen, which,  with  some  fat  and  cellular  tissue, 


separates  it  from  the  upper  part  of  the  levator 
anguli  oris.  It  covers  also  part  of  the  trian- 
gularis nasi. 

Its  action  is  to  raise  and  draw  a  little  out- 
wards the  upper  lip. 

Zi/gomaticus  minor  (3',  fig.  134)  is  a  narrow 
rounded  muscle,  often  wanting  It  arises  from 
the  external  surface  of  the  os  malas,  and  fre- 
quently also  from  the  deep  fibres  of  the  orbicu- 
laris palpebrarum,  by  which  its  origin  is  co- 
vered ;  it  proceeds  downwards  and  inwards, 
and  is  attached  to  the  skin  and  orbicularis  pal- 
pebrarum above  the  commissure  of  the  lips, 
where  its  fibres  are  also  confounded  with  those 
of  the  levator  labii  superioris  proprius. 

Relations. — This  muscle  is  covered  in  front 
by  the  orbicularis  palpebrarum  and  skin  ;  its 
posterior  surface  conceals  a  part  of  the  levator 
anguli  oris  and  of  the  labial  vein. 

Action. — It  is  an  associate  of  the  levator 
labii  superioris,  and  contributes  to  raise  the 
upper  lip  and  draw  it  a  little  outwards. 

Zygomaticus  major  (3,  jig.  134),  placed  to 
the  outer  side  and  a  little  below  the  preceding 
muscle,  is  of  a  rounded  form,  and  arises  by 
short  tendinous  slips  from  a  depression  on  the 
posterior  part  of  the  outer  surface  of  the  os 
malae,  near  its  lower  border.  Its  fibres  proceed 
downwards  and  inwards,  nearly  parallel  with 
those  of  the  lesser  zygomatic,  but  much  longer; 
and  expanding  a  little  below,  they  become  con- 
founded with  the  fibres  of  the  orbicularis  oris 
at  their  commissure,  and  with  those  of  the 
levator  labii  superioris,  levator  anguli  oris,  and 
depiessor  anguli  oris.  Its  superficial  fibres  are 
attached  to  the  skin. 

Relations. — This  muscle  is  surrounded  by 
fat,  which  separates  it  from  the  skin.  By  its 
deep  surface  it  rests  above  on  the  os  mala;  and 
the  masseter;  below,  it  is  separated  by  fat 
from  the  buccinator  and  the  levator  labii  supe- 
rioris :  it  crosses  also  the  labial  vein. 

Its  action  carries  the  commissure  of  the  lips 
upwards  and  outwards,  and  is  intermediate 
between  the  action  of  the  levator  and  the  buc- 
cinator: it  is  the  antagonist  of  the  levator  an- 
guli oris  in  drawing  the  lip  outwards;  its 
associate  in  raising  it.  When  both  these  mus- 
cles act,  the  commissure  of  the  lips  is  directly 
raised. 

Levator  anguli  oris  ( musculus  caninus):  ( c, 
Jig.  136). — To  expose  this,  the  levator  labii 
superioris  must  be  removed.  It  is  a  flat  qua- 
drilateral muscle,  which  arises  from  the  middle 
of  the  canine  fossa  of  the  upper  jaw,  and  be- 
coming somewhat  narrower  takes  a  direction 
downwards  and  a  little  outwards  and  forwards, 
to  terminate  at  the  commissure  of  the  hps, 
where  its  fibres  mingle  with  those  of  the  orbi- 
cularis, the  buccinator,  and  the  depressor 
anguli  oris. 

Relations. — Deeply  placed  above,  its  ante- 
rior surface  is  covered  by  the  infra-orbitar  ves- 
sels and  nerves,  and  by  fat,  which  separate  it 
from  the  levator  labii  superioris  and  the  lesser 
zygomatic.  Below  it  is  covered  by  the  zygo- 
matics major  and  the  integument.  The  pos- 
terior surface  of  this  muscle  rests  on  the  upper 


TACK. 


2-2.-. 


maxillary  bone  on  the  mucous  membrane  of 
the  mouth,  and  on  the  buccinator.  Its  action 
is  to  raise  the  commissure  of  the  lips,  and 
draw  it  a  little  inwards.  Its  action  when  as- 
sociated with  that  of  the  zygomatics  has  been 
already  explained. 

Depressor  anguli  oris  (triangularis  oris)  (t, 
Jig.  134)  is  a  thin,  triangular,  subcutaneous 
muscle,  situated  at  the  lower  part  of  the  face. 
It  arises  by  a  broad  base  from  the  lower  border 
of  the  inferior  maxilla,  and  from  the  surface  of 
the  bone  between  this  border  and  the  external 
oblique  line,  extending  from  the  chin  to  within 
half  an  inch  of  the  masseter.  The  fibres  con- 
verge and  ascend  towards  the  commissure  of 
the  lips,  the  posterior  fibres  taking  a  direction 
upwards  and  forwards,  the  middle  nearly  ver- 
tical, and  the  anterior  describing  a  curve  up- 
wards and  backwards:  they  all  terminate  at  the 
commissure  of  the  lips,  where  they  become 
united  with  those  of  the  orbicularis  and  of  the 
buccinator,  and  more  superficially  with  the 
great  zygomatic  and  levator  anguli  oris. 

Relations. — Its  superficial  surface  is  covered 
by  the  skin  and  by  the  fibres  of  the  platysma, 
with  which  it  is  mingled.  Its  deep  surface 
rests  upon  part  of  the  depressor  labii  inferioris 
and  buccinator:  above  it  is  connected  with  all 
the  muscles  of  the  commissure  and  with  the 
skin. 

Action. — This  muscle  draws  down  the  angle 
of  the  mouth,  and  in  this  respect  is  the  anta- 
gonist of  the  great  zygomatic  and  levator  an- 
guli oris. 

Depressor  labii  inferioris  ( quadrutus  menti), 
( d,  fig.  136, 137)  fiat  and  of  a  square  form,  is 
placed  internal  to  the  preceding,  which  partly 
conceals  it.  It  arises  from  the  inner  half  of 
the  external  oblique  line  of  the  lower  jaw,  and 
also  from  the  platysma,  with  whose  fibres  it  is 
continuous.  Its  fibres,  which  are  parallel,  pro- 
ceed upwards  and  inwards  to  be  attached  to 
the  lip ;  the  deep  fibres  mingle  with  those  of 
the  orbicularis;  the  superficial  pass  in  front  of 
that  muscle,  and  are  fixed  in  the  skin  of  the 
lip.  The  inner  fibres  decussate  above  with 
those  of  the  muscle  on  the  opposite  side; 
below,  with  those  of  the  levator  menti. 


Fig.  136. 


VOL.  II. 


Relations. — At  its  origin  this  muscle  is  co- 
vered by  the  triangularis,  and  elsewhere  by  the 
skin,  to  which  it  adheres  intimately  above.  Its 
deep  surface  covers  part  of  the  lower  jaw,  the 
mental  vessels  and  nerves,  part  of  the  orbicu- 
laris oris  and  levator  menti.  Through  the  an- 
gular interval  between  the  two  depressors  of 
the  lower  lip,  the  levatores  menti  pass  to  their 
insertion. 

Its  action  is  to  draw  downwards  and  out- 
wards one  side  of  the  lower  lip;  if  the  muscles 
on  both  sides  act,  the  lip  is  drawn  downwards 
and  extended  transversely.  The  stronger  ac- 
tions of  this  muscle  are  usually  accompanied 
by  those  of  the  platysma,  with  whose  fibres, 
as  we  have  seen,  it  is  continuous. 

Levator  menti  (honppe  du  menton )  (e,  fig. 
136, 137)  may  be  exposed  by  everting  the  lip  and 
dividing  the  mucous  membrane:  it  is  a  small 
round  muscle,  situated  at  the  lower  part  of  the 
face,  and  forming  on  each  side  a  great  part  of 
the  prominence  of  the  chin.  It  arises  in  the 
incisive  fossa  below  the  incisor  teeth  of  the 
lower  jaw,  external  to  the  symphysis,  and  pro- 
ceeds downwards  and  forwards:  it  passes  under 
the  lower  border  of  the  orbicularis  oris,  and 
emerging  between  the  depressor  labii  inferioris, 
expands  a  little  to  be  inserted  into  the  skin  of 
the  chin.  Its  fibres  below  are  mingled  with 
fat ;  internally  they  are  confounded  with  those 
of  the  fellow  muscle,  and  externally  with  the 
fibres  of  the  quadratus  menti. 

In  its  action  this  muscle  raises  and  corru- 
gates the  chin,  and  by  so  doing  raises  also  the 
lower  lip  and  throws  it  forward. 


Fig.  137. 


Buccinator  (b,  fig.  136,  137).  This  muscle 
is  situated  on  the  side  of  the  cheek,  and  to  ex- 
pose it  completely  it  is  necessary  to  divide  the 
muscles  attached  to  the  angle  of  the  mouth, 
and  to  remove  the  ramus  of  the  jaw  and  the 
muscle  attached  to  it.  The  buccinator  is  a 
broad  flat  muscle,  and  arises,  1.  behind  and 
in  the  middle  from  an  aponeurotic  line,  the 
pterygo-maxillary  ligament  or  inter-maxillary 
ligament,  which  is  common  to  it  and  the  su- 
perior constrictor  of  the  pharynx,  and  which  is 

Q 


220 


FACE. 


extended  between  tlie  lower  extremity  of  t!ie 
internal  pterygoid  plate  of  tlie  sphenoid  bone 
and  the  posterior  extremity  of  the  internal  ob- 
lique line  of  tlie  lower.  Above,  the  buccinator 
arises,  2.  from  the  outer  surface  of  the  upper 
alveolar  process,  between  the  first  malar  tooth 
and  the  tuberosity ;  3.  below  from  the  outer 
side  of  the  alveolar  border  opposite  the  three 
last  malar  teeth.  From  these  three  origins  the 
fibres  proceed  forwards,  the  superior  curving  a 
little  downwards,  the  inferior  upwards,  and 
the  middle  passing  horizontally  towards  the 
angle  of  the  mouth,  where  they  mingle  with 
the  fibres  of  the  orbicularis  and  the  elevators 
and  depressors  of  tlie  commissure.  The  infe- 
rior and  superior  fibres  become  shorter  as  we 
trace  them  forwards,  and  some  of  them  decus- 
sate at  the  angle  of  the  mouth  to  unite  with 
the  opposite  labial  half  of  the  orbicularis. 

The  fibres  of  the  buccinator  are  wavy,  over- 
lapping each  other,  so  that  they  admit  of  great 
distention,  which  is,  however,  limited  by  a 
buccal  fascia,  which  is  given  off  from  the 
pterygo-maxillary  ligament. 

Relations. — The  buccinator  is  deeply  situated 
behind,  where  it  is  covered  by  the  ramus  of 
the  jaw  and  the  edge  of  the  masseter,  from 
which  it  is  separated  by  a  quantity  of  fat, 
which  projects  beyond  the  mass,  fills  up  the 
hollow  in  front  of  the  masseter,  and  is  always 
found  even  in  thin  subjects.  In  the  middle 
it  corresponds  to  the  buccal  vessels  and  nerves 
and  to  tlie  transverse  facial  artery,  which  runs 
nearly  parallel  to  its  fibres,  and  to  the  duct 
of  the  parotid  gland,  which,  resting  at  first 
upon  its  fibres,  pierces  them  opposite  the 
second  molar  tooth  of  the  upper  jaw,  and 
opens  obliquely  into  the  mouth.  A  buccal 
fascia  covers  the  posterior  half  of  the  muscle. 
At  the  commissure  the  buccinator  is  covered 
by  the  muscles  which  are  attached  to  the  angle 
of  the  mouth,  and  is  crossed  at  right  angles 
by  the  external  maxillary  artery  and  vein.  By 
its  internal  surface  this  muscle  covers  the 
mucous  membrane  of  the  mouth,  from  which 
it  is  only  separated  by  a  layer  of  buccal 
glands. 

Action. — This  muscle,  being  fixed  behind, 
above,  and  below,  acts  principally  in  front  on 
the  commissure  of  the  lips,  which  it  draws 
horizontally  backwards,  elongating  the  aperture 
of  the  mouth  transversely,  and  throwing  the 
cheek  into  the  vertical  folds  which  are  so  re- 
markable in  old  age.  In  this  respect  it  is 
the  direct  antagonist  of  the  orbicularis  oris: 
if  both  these  muscles  act  together,  the  lips  are 
extended  and  pressed  against  the  teeth.  When 
the  cavity  of  the  mouth  is  distended  with  air 
or  liquids,  this  muscle  is  protruded  at  the 
checks,  and  its  fibres  become  separated  and 
curved.  If  now  the  muscle  acts,  the  fibres 
become  straightened,  and  the  fluid  is  expelled 
from  the  mouth  either  abruptly  or  gradually 
according  to  the  resistance  of  the  orbicularis. 
This  action  of  the  orbicularis  is  exemplified 
either  in  spirting  fluids  from  the  mouth,  or 
in  playing  on  wind  instruments.  In  mastica- 
tion the  buccinator  presses  the  food  from 
between  the  cheek  and  gums  into  the  cavity 


of  the  mouth.  It  assists  also  in  deglutition 
when  the  mouth  is  closed,  by  pressing  the 
food  backwards  towards  the  pharynx. 

Among  the  muscles  of  the  face,  it  is  ne- 
cessary to  allude  to  some  parts  of  the  platysma, 
which  are  not  only  seen  in  this  region,  but 
which  contribute  materially  to  the  motion  and 
expression  of  the  face.  The  platysma  ( p,  p,p, 
Jig.  138)  is  a  large,  broad,  membranous  layer  of 
fibres,  which  extend  from  the  upper  and  an- 
terior part  of  the  chest,  where  they  commence 
in  the  subcutaneous  tissue,  upwards  over  the 
anterior  and  lateral  part  of  the  neck,  to  the 
jaw  and  lower  part  of  the  face,  where  they 
are  inserted  above.  The  whole  superficial 
surface  of  the  muscle  is  subcutaneous,  but 
less  firmly  attached  to  the  integument  just 
under  the  jaw  than  elsewhere.  The  under 
surface  of  its  cervical  portion  is  in  relation 
with  numerous  important  parts  on  the  face: 
it  covers  from  before  backwards  the  lower 
part  of  the  chin,  the  quadratus  menti,  the 
triangularis  oris,  the  base  of  the  lower  jaw, 
tlie  facial  vessels,  and  part  of  the  masseter. 
The  arrangement  of  its  facial  portion  is  all 
that  need  be  described  here. 


Fig.  138. 


'    \  '^v'vvv 

As  the  fibres  of  the  muscle  incline  upwards 
towards  the  median  line,  they  meet  below  the 
symphysis  of  the  chin,  and  some  ascend  as 
high  as  the  levator  menti.  Externally  the 
fibres  seem  to  split  to  enclose  the  depressor 
anguli  oris,  and  to  proceed  upwards  and  for- 
wards with  that  muscle  and  the  quadratus 
menti  to  the  lower  lip  and  its  angle.  The 
middle  fibres  are  attached  to  the  base  of  the 
jaw,  and  posteriorly  they  mount  over  the 


FACE 


227 


angle,  and  are  lost  on  the  fascia  of  the  masseter. 
A  curious  slip  crosses  these  transversely,  de- 
scending a  little  from  the  fascia  covering  the 
parotid  gland  towards  the  angle  of  the  mouth. 
It  is  the  risorius  Santorini,  which  is,  however, 
often  wanting.  The  platysma  draws  clown 
the  whole  of  the  lower  part  of  the  face,  or, 
acting  more  slightly,  depresses  the  lower  lip 
and  the  commissure  in  conjunction  with  their 
proper  depressors.  The  slip  called  risorius, 
on  the  contrary,  raises  the  angle  of  the  mouth. 

The  only  fasciae  of  the  face  are,  1.  a  pal- 
pebral fascia,  which  connects  the  convex  edges 
of  the  tarsal  cartilages  to  the  border  of  the 
orbit;  and,  2.  a  buccal  fascia,  which,  ex- 
tending forward  from  the  intermaxillary  liga- 
ment, covers  the  posterior  half  of  the  buccinator 
muscle  :  anterior  to  this  it  becomes  lost  in  the 
surrounding  cellular  tissue. 

General  review  of  t lie  muscles  of  the  face. — 
With  one  exception,  all  the  muscles  of  the 
face  are  attached  at  one  part  to  bone,  and  at 
another  either  to  the  skin  or  to  some  other 
muscle  :  their  fibres  are  also  red  and  firm  at 
their  fixed  attachment,  pale  and  thinner  at 
their  moveable  extremity.  With  the  exception 
of  the  orbicularis  oris,  which  is  a  symmetrical 
muscle,  all  the  others  are  arranged  in  pairs, 
one  on  each  side  of  the  face.  The  mouth 
being  the  most  moveable,  has  by  far  the 
greatest  number  grouped  around  it.  It  pos- 
sesses, 1.  a  sphincter,  the  orbicularis  oris, 
the  important  action  of  which  on  the  lips  in 
suction,  respiration,  whistling,  blowing,  and 
playing  on  wind  instruments,  in  speech  and  in 
expression,  has  already  been  partly  spoken  of. 
The  associate  of  this  muscle  is  the  levator 
menti.  2.  The  antagonist  of  this  are,  a,  the 
naso-labialis,  the  transversalis  nasi,  the  levator 
labii  superioris,  both  proper  and  common  to 
it  and  the  nose,  and  which  raise  the  upper 
lip ;  b,  the  depressor  labii  inferioris  and  pla- 
tysma, which  draw  down  the  lower  lip ;  c, 
the  buccinator,  which  extends  the  aperture  of 
the  mouth  transversely ;  d,  the  zygomatics,  the 
risorius  Santorini,  and  the  levator  anguli  oris, 
which  draw  the  commissure  upwards  ;  and,  e, 
the  depressor  anguli  oris  and  platysma,  which 
draw  it  downwards. 

About  the  eyes  there  are  on  each  side,  1. 
a  sphincter,  the  orbicularis  palpebral  and  pal- 
pebralis,  with  the  associate,  the  corrugator 
supercilii ;  2,  the  dilators,  the  occipato  frontalis 
and  levator  palpebrae.  About  the  nose  there 
are,  1,  a  constrictor,  the  depressor  alai  nasi; 
2.  the  dilators,  levator  labii  superioris  ala?que 
nasi  and  the  dilator  nasi;  3.  the  triangularis 
nasi,  which  probably  both  dilates  and  contracts 
the  orifice  of  the  nostrils  according  to  the 
attachment,  which  is  fixed. 

The  muscles  of  the  face,  including  the 
pyramidalis,  the  levator  palpebrae,  the  naso- 
labialis,  and  the  dilator  alae  nasi,  are  sixteen 
pairs  in  number;  if  we  add  the  occipito- 
frontalis,  the  corrugator  supercilii,  and  the 
platysma,  nineteen  pairs,  and  one  symmetrical, 
the  orbicularis  oris.  Of  these,  four  pairs 
belong  to  the  eye,  three  pairs  to  the  nose,  ten 
pairs  and  one  single  one  to  the  mouth :  two 


pairs  are  common  to  the  mouth  and  the 
nose. 

The  use  of  the  muscles  of  the  face  with 
respect  to  expression  is  a  subject  of  so  much 
interest,  and  involves  so  many  collateral  facts, 
that  it  will  be  better  considered  under  the 
separate  article  Physiognomy.  It  will  be 
sufficient  to  observe  here  that  the  muscles  which 
express  lively  feeling  and  the  gay  passions, 
such  as  the  oecipito-frontalis,  the  levator  pal- 
pebrarum, the  levators  and  dilators  of  the  lips 
and  their  commissure,  do  for  the  most  part 
either  raise  or  draw  the  parts  from  the  median 
line ;  and  that  those  muscles  which  manifest 
the  sadder  feelings  and  the  darker  passions, 
as  the  corrugator  supercilii,  the  pyramidalis, 
the  levator  menti,  the  depressors  of  the  lower 
lip  and  its  commissure,  either  depress  the 
parts  or  draw  them  from  the  median  line. 
The  constant  and  habitual  exercise  of  either 
of  these  sets  of  muscles  leaves  corresponding 
permanent  folds  in  the  skin,  which  are  in- 
dicative of  the  habitual  feelings  and  passions 
of  the  individual. 

T/ie  integuments  of  the  face. — The  skin  of 
the  face  is,  with  the  exception  of  some  parts, 
remarkable  for  its  tenuity,  for  its  abundant 
supply  of  vessels,  nerves,  and  follicles ;  for 
the  growth  of  hair,  which  covers  some  parts 
of  it;  and  for  its  attachment  to  the  subjacent 
muscles.  The  vascularity  of  the  skin  in  some 
parts  is  even  beautiful,  tinting  the  cheek  and 
lips,  as  in  the  act  of  blushing,  assisting  in  the 
expression  of  the  feelings  and  passions.  The 
subcutaneous  cellular  tissue  is,  in  general,  very 
dense  in  this  region,  and  is  mingled  with  more 
or  less  fat,  except  on  the  eyelids,  where  it  is 
loose,  delicate,  and  quite  destitute  of  adipose 
tissue.  Generally  speaking,  the  skin  of  the 
face  is  more  adherent,  and  the  subjacent  cel- 
lular tissue  is  more  dense  and  less  fatty,  along 
the  median  line  than  at  the  lateral  parts ;  the 
nose  and  lips  offer  examples  of  this  fact.  At 
the  sides  the  cellular  tissue  is  looser  below, 
near  the  base  of  the  jaw,  than  higher  up  on 
the  cheeks.  Most  of  the  muscles  are  more  or 
less  surrounded  with  fat,  which,  however,  par- 
ticularly abounds  on  the  cheeks  and  between 
the  masseter  and  buccinator  muscles. 

Vessels  of  t lie  face. — The  arteries  are  de- 
rived chiefly  from  the  external  carotid,  viz. 
1.  the  external  maxillary  or  the  facial  artery, 
and  its  branches;  2.  branches  from  the  tem- 
poral, particularly  the  transverse  facial  artery  ; 
3.  branches  from  the  internal  maxillary,  more 
particularly  the  infra-orbitar,  the  buccal,  and 
the  superior  and  inferior  dental  arteries ;  4. 
some  arteries  which  emerge  from  the  orbit  and 
are  derived  from  the  ophthalmic  branch  of  the 
internal  carotid.  These  vessels  communicate 
very  freely  with  each  other,  and  form  with 
their  accompanying  veins  an  intricate  vascular 
network  over  the  face.  See  Carotid  Ar» 
tery. 

The  veins  are  principally  branches  of  the 
external  jugular,  viz.  1.  the  facial  vein  with 
its  branches,  which  correspond  generally  to  the 
trunk  and  branches  of  the  facial  artery,  except 
that  the  facial  vein  is  rather  more  superficial 

92 


FACE. 


and  further  from  the  median  line  than  the 
artery  ;  2.  the  transverse  facial  vein  and  some 
other  small  branches  of  the  temporal;  3.  veins 
corresponding  to  the  branches  of  the  internal 
maxillary  artery  already  mentioned ;  and, 
lastly,  some  veins  about  the  nose  and  brow, 
which  are  connected  with  the  ophthalmic  vein 
within  the  orbit.  Both  arteries  and  veins  are 
imbedded  in  the  adipose  tissue,  and  are  often 
remarkably  tortuous,  more  especially  the  ar- 
teries, in  old  persons.  Their  trunks  and 
branches  open  in  a  direction  towards  the  me- 
dian line,  particularly  at  the  upper  part  of  the 
face. 

The  lymphatics  are  much  more  numerous 
than  those  of  the  cranium,  and  follow  prin- 
cipally the  course  of  the  bloodvessels,  and 
terminate  in  the  submaxillary  and  parotid  lym- 
phatic ganglions ;  in  their  course  they  traverse 
some  ganglions,  which  are  situated  on  the  buc- 
cinator. 

The  superficial  lymphatics  arise  from  all 
parts  of  the  face,  and,  accompanying  the  su- 
perficial vessels,  end  in  the  submaxillary  gan- 
glions; some  of  them  traverse  the  smaller 
buccal  ganglions. 

The  deep  lymphatics  are  situated  in  the  zy- 
gomatic and  pterygo-maxillary  fossae  ;  they 
also  accompany  the  bloodvessels,  and  ter- 
minate in  the  deep  parotid  and  submaxillary 
ganglions. 

The  lymphatic  ganglions  of  the  face  are  prin- 
cipally situated  along  the  base  of  the  jaw,  and 
are  termed  the  submaxillary  ganglions.  Others 
are  placed  on  the  jaw  and  buccinator,  in  front 
of  the  masseter  (the  buccal  ganglions),  and 
follow  the  facial  vessels.  Some  lymphatic 
ganglions  are  situated  underneath  the  zygoma 
(the  zygomatic  ganglions) ;  and  others,  more 
numerous,  are  placed  upon,  within,  or  under- 
neath the  parotid  gland,  and  are  termed  the 
parotid  ganglions.  The  deep  lymphatics  of 
the  orbits,  nose,  and  mouth,  will  be  described 
with  those  cavities. 

The  nerves  (tf  the  face  are  derived  from  the 
three  divisions  of  the  fifth  and  from  the  portio 
dura  of  the  seventh  cerebral  nerves.  The 
branches  from  the  fifth  emerge  on  the  face, 
1.  from  the  orbit;  these  come  from  the  oph- 
thalmic or  first  division  of  the  fifth,  and  are 
the  frontal,  the  supra-trochlear,  the  infra- 
trochlear,  and  the  lachrymal :  2.  from  the 
infra-orbitar  foramen  escape  the  infra-orbitar 
nerve,  from  the  second  division  of  the  fifth  or 
superior  maxillary,  and  from  the  same  source, 
emerging  from  underneath  the  ramus  of  the 
jaw,  the  buccal  nerves:  3.  from  the  mental 
foramen  emerge  branches  of  the  inferior  den- 
tal nerve,  derived  from  the  third  division  of 
the  fifth  or  the  inferior  maxillary  ;  and  from 
the  same  source,  piercing  the  masseter,  the 
masseteric  nerves.  The  portio  dura,  after  turn- 
ing over  the  posterior  border  of  the  lower  jaw, 
forms  a  plexus  (the  pes  anserinus)  within  the 
parotid  gland,  and  divides  into  a  great  num- 
ber of  branches,  which  are  distributed  on  the 
face,  and  which  have  received  various  names 
corresponding  to  the  regions  where  they  run. 
The  branches  of  the  fifth  nerve  which  are  dis- 


tributed to  the  face  principally  supply  the  in- 
teguments, and  those  of  the  portio  dura  the 
muscles.  Some  filaments,  however,  of  the 
fifth,  such  as  the  buccal  branch,  derived  from 
the  ganglionous  portion,  supply  muscles;  and, 
on  the  other  hand,  some  cutaneous  twigs  are 
sent  from  the  portio  dura  of  the  seventh  to  the 
commissure  of  the  lips.  Both  nerves  freely 
anastomose  with  each  other  on  the  face.  For  a 
more  particular  account  of  these  nerves  and  of 
their  functions,  see  Fifth  pair  of  Nerves, 
Seventh  pair  of  Cerebral  Nerves,  and 
Physiognomy. 

Abnormal  conditions  of  the  soft  parts  of  the 
face. — The  muscles  of  the  face  offer  nothing 
very  remarkable  in  their  abnormal  conditions  ; 
like  others,  they  become  much  developed  by 
constant  exercise,  and  on  the  other  hand,  when 
paralytic,  they  waste  and  lose  both  their  colour 
and  consistence;  their  fibres  have  been  ob- 
served occasionally  to  have  degenerated  into  a 
fatty  substance,  and  the  trichina  spiralis  has 
also  been  found  among  them  as  among  those 
of  other  voluntary  muscles. 

The  bloodcessels  of  the  face  are  subject  to  no 
anomalies  in  their  course  which  call  for  notice 
in  this  place.  It  may  be  remarked,  however, 
that  they  vary  in  size  in  different  individuals, 
and  are  sometimes  superficially  and  sometimes 
more  deeply  situated  among  the  soft  parts 
around  ;  their  tortuosity  in  old  age  has  already 
been  adverted  to. 

Vascular  nevi  are  not  unfrequentlv  found  on 
the  face,  in  some  cases  deeply  situated  within 
the  cavities  or  underneath  the  bones;  in  others, 
and  more  commonly,  they  lie  superficially  in 
the  skin  and  subcutaneous  tissues.  They  occur 
of  the  venous,  arterial,  or  mixed  kinds.  The 
first  sometimes  attain  a  considerable  magni- 
tude, as  I  have  witnessed  in  the  case  of  an  old 
woman,  in  whom  such  a  naevus  grew  on  one 
cheek  and  lip,  and  exceeded  in  size  the  whole 
face.  Such  swellings  are  easily  compressed, 
and  often  produce  no  other  inconvenience  than 
that  of  their  deformity  and  weight.  The  arte- 
rial njevus,  however,  and  more  especially  when 
deeply  seated,  is  sometimes  a  formidable  dis- 
ease, which  may  involve  all  the  surrounding 
structures  and  ultimately  prove  fatal.  The  cu- 
taneous capillaries  of  the  cheeks,  and  about  the 
tip  and  ala;  of  the  nose,  often  become  enlarged 
and  varicose,  presenting  a  peculiar  appearance, 
which  is  not  uncommon  in  hard  drinkers. 

The  lymphatic  glands  of  the  face  are  particu- 
larly liable  to  inflammation,  enlargement,  and 
suppuration.  In  scrofula  they  often  form  im- 
mense swellings  along  the  base  of  the  jaw  and 
about  the  parotid  gland,  sometimes  remaining 
permanently  enlarged,  and  sometimes  suppura- 
ting and  terminating  in  abscesses  difficult  to 
heal. 

The  nerves  of  the  face  are  liable  to  be  pressed 
upon  and  irritated  by  the  enlarged  glands  and 
by  the  tumours  in  this  part  of  the  body.  The 
face  is  also  subject  to  a  most  distressing  com- 
plaint, termed  tic  dovlouroux,  which  may  arise 
spontaneously  or  from  injury,  and  which  ap- 
pears to  affect  particularly,  if  not  exclusively, 
the  branches  of  the  fifth  pair  of  nerves,  and 


FASCIA. 


229 


more  especially  the  infra-orbitar.  Neuralgia 
of  the  lower  part  of  the  face  seems,  however,  in 
some  instances  to  follow  the  course  of  those 
branches  of  the  cervical  plexus  which  proceed 
toward  this  region.  Division  of  the  nerves, 
though  it  sometimes  checks,  seldom  cures  this 
painful  affection,  for  the  divided  nerves  spee- 
dily reunite,  and  the  complaint  returns ;  and 
this  takes  place  even  after  a  portion  of  the 
nerve  has  been  removed.  Spasmodic  affections 
of  the  face  are  connected  with  the  branches  of 
the  portio  dura  :  both  nerves  are  of  course  sub- 
ject to  palsy. 

The  cellular  tissue  of  the  face  is  abundant, 
vascular,  mingled  generally  with  more  or  less 
fat,  and  in  some  places,  as  on  the  eyelids,  is  so 
lax  as  to  be  peculiarly  liable  to  infiltration 
with  fluids.  Sometimes  it  becomes  emphyse- 
matous, in  cases  of  wounds  of  the  frontal  sinuses 
and  larynx.  It  is  easily  affected  by  erysipelas, 
and  is  the  common  seat  of  abscesses,  which, 
however,  as  there  is  no  fascia  to  confine  the 
matter,  rarely  attain  any  considerable  size,  but 
soon  make  their  way  towards  the  surface  of  the 
skin.  When,  indeed,  the  pus  forms  on  the 
forehead  between  the  muscles  and  the  pericra- 
nium, or  beneath  the  fascia  covering  the  parotid 
gland,  or  beneath  that  investing  the  masseter 
and  posterior  part  of  the  buccinator  muscles, 
the  matter  being  more  confined  is  longer  in 
arriving  at  the  surface,  and  is  productive  of 
more  pain  than  in  the  former  instance.  En- 
cysted tumours  are  not  unfrequently  formed  in 
this  structure  of  the  face. 

The  skin  of  the  face,  from  its  vascularity  and 
the  almost  homogeneous  mass  which  it  forms 
with  the  subjacent  tissues,  readily  unites  after 
incised  wounds,  and  hence  the  success  which 
has  attended  the  attempts  at  reparation  of  some 
parts  of  this  region,  such  as  the  nose,  cheek, 
and  lips ;  the  extensibility  of  the  skin  also 
favours  such  operations.  Punctured  and  con- 
tused wounds  of  the  face  are  apt  to  produce 
erysipelas  when  they  affect  those  parts  where 
the  cellular  tissue  is  most  dense,  as  on  the  nose 
and  the  prominence  of  the  cheek.  Abscesses 
are  the  more  common  result  where  the  cellular 
tissue  is  looser.  The  skin  of  the  face  becomes 
swollen  and  thickened  in  some  complaints 
which  attack  it,  such  as  scrofula,  which  produ- 
ces enlargement  of  the  lips  and  nose,  and  ele- 
phantiasis, cancer,  and  a  few  other  diseases 
which  affect  it  more  permanently.  It  is  sub- 
ject also  to  freckles,  stains,  and  discolorations 
of  various  kinds,  enlargement,  inflammation, 
and  induration  of  its  follicles;  to  a  variety  of 
cutaneous  eruptions ;  to  ulcerations  from  scro- 
fula, scirrhus,  lupus,  8cc.  which  frequently 
make  great  ravages  not  only  in  the  soft  parts  of 
the  face,  but  even  in  the  bones ;  to  tubercles, 
warts,  tumours,  and  anomalous  growths  of 
various  kinds ;  and  finally  to  boils.  Its  vas- 
cularity renders  it  more  liable  than  in  other 
parts  of  the  body  to  receive  the  impression  of 
small-pox  pustules.  Like  the  bones,  the  soft 
parts  of  the  face  are  subject  to  congenital  mal- 
formation. 1.  Its  apertures  may  be  closed 
more  or  less  firmly  ;  this  happens  with  the  eye- 
lids, nostrils,  and  lips.    2.  There  may  be  de- 


fects of  growth,  as  fissures  in  the  lips,  or  hare- 
lip, which  may  be  single  or  double,  and  exist 
alone  or  in  combination  with  fissures  of  the 
palate.  The  fissure  may  vary  in  depth,  some- 
times, in  the  upper  lip,  extending  into  one  of 
the  nostrils,  and  at  others  only  affecting  the 
border  of  the  lip.  Congenital  cleft  of  the  lower 
lip  is  very  rare,  and  is  never  combined  with 
fissure  of  the  bone.  The  nose  is  sometimes 
fissured,  presenting  no  cartilaginous  septum, 
and  but  one  large  orifice  or  nostril.  Occasion- 
ally a  congenital  fissure  has  been  observed  in 
the  cheek.  The  abnormal  conditions  of  the 
teeth,  the  orbits  and  their  contents,  of  the 
lachrymal  apparatus,  and  of  the  cavities  of  the 
nose  and  mouth,  will  be  found  under  the  seve- 
ral articles  on  these  subjects. 

For  the  BIBLIOGRAPHY  of  this  article,  see 
Anatomy  (Introduction). 

(R.  Partridge.) 

FASCIA,  (in  general  anatomy,)  (Binde, 
se/iinge  Sc/ieide,  Flechsenhdute,  Germ.)  This 
term  is  applied  to  certain  membranous  expan- 
sions, existing  in  various  regions  of  the  body, 
and  forming  coverings  to  particular  parts. 
These  expansions  are  composed  either  of  cellu- 
lar tissue,  more  or  less  condensed,  or  of  fibrous 
tissue,  the  former  being  the  cellular  fascia,  the 
latter  the  aponeuroses  or  aponeurotic  fascia . 
The  structure  and  connexions  of  a  considerable 
number  of  the  fascia?  are  highly  interesting,  as 
well  with  reference  to  correct  diagnosis  and 
prognosis  in  surgical  disease,  as  in  regard  to 
the  mode  of  proceeding  in  various  operations. 

1.  Cellular  fascia. — These  are  lamellae  of 
cellular  membrane  of  variable  density,  some- 
times loaded  with  fat,  at  other  times  totally 
devoid  of  it  The  best  example  of  this  form  of 
fascia  is  the  layer  of  cellular  membrane  which 
is  immediately  subjacent  to  the  subcutaneous 
cellular  tissue  all  over  the  body,  and  in  most 
places  so  intimately  connected  with  it  as  to  be 
inseparable ;  these  in  fact  form  but  one  mem- 
brane, which,  although  essentially  the  same 
everywhere,  yet  exhibits  characters  peculiar 
almost  to  each  region  of  the  body;  it  is  gene- 
rally known  under  the  name  of  the  superficial 
fascia.  Although  this  fascia  is  universal,  there 
are,  nevertheless,  certain  regions  where,  from 
its  greater  importance,  it  has  been  more  care- 
fully examined  than  in  others,  and  tcwhich  we 
may  best  refer  in  order  to  investigate  its  pecu- 
liar characters.  Of  these  regions  those  of  the 
abdomen  and  the  neck  stand  pre-eminent ;  here 
this  fascia  constitutes  a  distinct  membranif'orm 
expansion,  and  the  principal  variety  it  pre- 
sents in  different  subjects  is  as  regards  the 
greater  or  less  quantity  of  fat  deposited  in  it. 
Where  a  tendinous  or  fibrous  expansion  does 
not  lie  immediately  under  it,  this  fascia  sends 
processes  from  its  deep  surface  to  invest  the 
subjacent  muscles  and  other  parts;  this  is  very 
manifest  in  the  case  of  the  fascia  of  the  neck  ; 
and  in  general  it  may  be  stated  that  the  super- 
ficial fascia  has  a  more  or  less  intimate  connec- 
tion with  the  proper  cellular  covering  of  sub- 
jacent organs,  whether  muscles  or  tendon> 


230 


FASCIA. 


The  arrangement  to  which  we  allude  in  the 
fascia  of  the  neck  may  be  satisfactorily  traced 
from  the  median  line  on  the  anterior  surface  of 
the  neck,  proceeding  outwards  on  each  side. 
On  the  median  line  the  fascia;  of  opposite  sides 
are  intimately  united  so  as  to  form  a  dense  line, 
called  by  some  anatomists  liiiea  alba  cervkulis; 
thence  on  each  side  the  fascia  divides  into 
laminae,  investing  the  sterno-hyoid  and  thyroid 
muscles,  the  carotid  artery  and  jugular  vein, 
the  sterno-mastoid,  and  other  muscles ;  and 
thus  anatomists  come  to  describe  a  superficial 
and  a  deep  layer  of  the  cervical  fascia;  the 
former  being  continuous  with  the  superficial 
fascia  covering  the  muscles  on  the  anterior 
part  of  the  thorax,  the  latter,  intimately  con- 
nected with  all  the  deep-seated  structures  in 
the  neck,  may  be  traced  outwards  behind  the 
sterno-mastoid  muscle,  along  the  posterior  edge 
of  which  it  becomes  again  united  with  the  su- 
perficial layer;  the  fascia,  thus  re-constructed, 
passes  through  the  triangular  space  which  in- 
tervenes between  the  muscle  last-named  and 
the  trapezius,  and  may  be  traced  over  that 
muscle  to  become  continuous  with  the  superfi- 
cial fascia  on  the  back.  It  is  the  deep  layer 
of  this  fascia  which  was  described  by  Godman 
of  Philadelphia*  as  passing  downwards  behind 
the  sternum  to  be  continuous  with  the  fibrous 
pericardium.  This  description  has  been  sub- 
sequently confirmed  by  more  than  one  anato- 
mist in  France,  although  denied  by  Cru- 
veilhier,  and  in  this  country  by  Sir  Astley 
Cooper,t  who  has  described  it  in  the  same 
manner,  apparently  without  being  acquainted 
with  the  previously  recorded  statements  of  the 
anatomists  above  referred  to ;  I  may  add  that 
I  have  myself  in  many  instances  proved  the 
accuracy  of  Godman's  description.  The  cer- 
vical fascia  is  continuous  superiorly  with  the 
superficial  fascia  on  the  face ;  and  inferiorly, 
besides  tracing  it  into  the  pectoral  region,  we 
can  follow  it  over  the  shoulder  into  the  arm. 
The  cervical  fascia,  in  a  great  part  of  its  extent, 
is  not,  as  the  superficial  fascia  elsewhere,  in 
intimate  connexion  with  the  subcutaneous  cel- 
lular tissue,  but  is  separated  from  it  on  each 
side  of  the  neck  by  the  fibres  of  the  platysma 
myoides.  From  this  brief  account  of  the  cervi- 
cal fascia,  (we  refer  for  the  more  particular 
description  to  the  article  on  the  surgical  ana- 
tomy of  the  Neck,)  we  learn  one  characteristic 
of  the  superficial  fascia,  namely,  its  continuity 
all  over  the  body. 

The  superficial  fascia  of  the  abdomen  has 
attracted  the  attention  of  anatomists  and  sur- 
geons from  its  connexion  with  all  herniary 
tumours  in  that  region.  I  n  its  arrangement  it  is 
much  less  complex  than  the  cervical  fascia, 
being  a  uniform  membranous  expansion  spread 
oVer  the  superficial  muscular  and  aponeurotic 
structures  of  the  abomen,  continuous  on  either 
side  and  posteriorly  with  the  superficial  fascia 
of  the  lumbar  regions,  and  inferiorly  with  that 
of  the  inferior  extremities.  See  the  description 
of  it  in  the  article  Abdomen. 

*  Anatomical  Investigations,  Philiidclph.  1821. 
\  On  ihr  thymus  gland. 


The  superficial  fascia  of  the  limbs  is  com- 
pletely confounded  with  the  subcutaneous  cel- 
lular tissue,  and  wants  that  condensation  by 
which  on  the  trunk  generally,  but  particularly 
in  the  neck  and  abdomen,  it  is  distinguished. 

There  can  be  no  doubt  that  the  superficial 
fascia  is  no  more  than  condensed  cellular  mem- 
brane, and  its  variety  of  appearance  in  different 
regions  depends  in  a  great  measure  upon  pecu- 
liarities in  the  motions  and  arrangement  of  the 
parts  contained  in  those  regions,  e.g.  wherever 
the  muscles  of  a  part  are  in  very  frequent  ac- 
tion, and  at  the  same  time  the  fascia  is  com- 
pressed between  the  integument  and  the  mus- 
cles, it  sutlers  condensation  ;  this  is  conspicuous 
in  the  abdomen,  where  there  is  almost  incessant 
muscular  action  in  consequence  of  the  respi- 
ratory movements,  and  where  the  weight  of  the 
viscera,  thrown  forwards  in  the  erect  posture, 
occasions  a  considerable  pressure  upon  the  an- 
terior and  lateral  portions  of  the  abdoniii;al 
parietes.  The  deposition  of  adeps  to  any  great 
extent  is  unfavourable  to  the  existence  of  a 
distinct  fascia  superficialis,  which  is  thereby,  as 
it  were,  decomposed,  and  hence  this  fascia  is 
not  distinct  from  the  subcutaneous  cellular 
tissue  in  those  regions  where,  either  habitually 
or  preternaturally,  this  substance  is  largely  de- 
posited. 

The  superficial  fascia  is  identified  with  the 
subcutaneous  cellular  membrane  in  the  cranial 
regions,  a  circumstance  which  seems  attributa- 
ble to  the  firm  adhesion  of  the  aponeurotic  ex- 
pansion of  the  occipito-frontalis  muscle  to  the 
subcutaneous  tissue,  and  also  the  cutaneous 
insertion  of  other  muscles  ;  to  a  similar  cause 
we  may  ascribe  the  indistinctness  of  this  fascia 
in  the  face  also,  as  likewise  to  the  great  depo- 
sition of  fat  in  some  parts  of  this  region.  In 
the  pectoral  region  it  is  attenuated,  and  is 
more  intimately  connected  with  the  proper 
cellular  covering  of  the  great  muscles  than 
with  the  subcutaneous  cellular  tissue. 

Where  the  superficial  fascia  has  suffered 
condensation  to  a  considerable  extent,  and 
there  is  a  complete  absence  of  adipose  sub- 
stance, it  assumes  an  appearance  which  has 
given  rise  to  the  designation  "  fibro-cellular," 
in  consequence  of  the  existence  of  thick,  white, 
and  opaque  bundles  intersecting  the  membrane 
in  various  directions;  these  bundles  seem  to 
be  produced  by  the  close  application  of  the 
walls  of  the  cells  to  each  other,  and  the  conse- 
quent obliteration  of  their  cavities.  This,  how- 
ever, I  believe  is  the  nearest  approach  that  the 
superficial  fascia  makes  to  fibrous  membrane  ; 
and  I  am  strongly  disposed  to  question  the 
accuracy  of  Velpeau's  assertion,  that  it  is  some- 
times transformed  into  the  yellow  fibrous  or  into 
muscular  tissue.  The  elastic  abdominal  ex- 
pansion, described  by  Girard,  is  certainly  not 
a  conversion  of  the  superficial  fascia,  but  of 
the  muscular  aponeurosis. 

Among  the  cellular  fasehe,  Velpeau*  de- 
scribes a  layer  of  cellular  membrane,  pretty 
uniform  in  its  characters,  and  in  some  localities 
of  great  practical  importance,  and  gives  it  the 

*  Anat.  Chiiurg.  t.  i.  p.  42. 


FAT. 


231 


name  fascia  supeijicialis  interna.  It  is  in 
contact  with  the  serous  membranes  of  the  prin- 
cipal cavities  in  the  body,  with  those  of  the 
abdomen,  thorax,  and  pelvis  in  particular;  in 
the  former  of  which  it  has  attracted  most  atten- 
tion under  the  denomination  of  {he  fascia  pro- 
pria. This  cellular  layer  lies  between  the 
serous  membrane  and  the  fibrous  layer  which 
lines  the  parietes  of  the  cavities,  as  for  instance 
the  fascia  transversalis  in  the  abdomen ;  and 
consequently  in  this  last  cavity,  when  any 
viscus  is  protruded,  carrying  a  peritoneal  sac 
before  it,  this  cellular  layer  uniformly  forms  the 
immediate  investment  of  the  sac,  and  is  there- 
fore called  fascia  propria,  a  hernial  covering 
which  every  practical  surgeon  well  knows  is 
often  of  considerable  density  and  thickness, 
and  to  which  indeed  is  attributable  the  so-called 
thickening  of  the  sac  itself. 

2.  Aponeuroses  or  aponeurotic  fascne. — This 
appellation  should  be  confined  to  those  textures 
which  are  purely  fibrous,  and  belong  to  either 
the  white  fibrous  tissue  or  the  yellow.  In  man, 
they  belong  entirely  to  the  former  class,  but  we 
see  some  interesting  examples  among  the  lower 
animals,  where,  while  the  same  characters  as  to 
intimate  texture  are  preserved,  they  assume  a 
yellow  colour,  and  exhibit  most  manifestly  the 

property  of  elasticity.  J^§^%  

The  greatest  numbe/^^fhe  fibrous  aponeu- 
roses are  connected  witliv muscular  fibres,  and 
in  fact  serve  as  tendons;  to  {facta,,  and  are  de- 
scribed as  such.  Of  these  we  have  the  best 
examples  in  the  fibrous  aponeuroses  of  the  ab- 
dominal muscles,  by  which  a  considerable  por- 
tion of  the  paries  of  this  cavity  is  constructed 
of  a  resisting  inelastic  material,  which  is  at  the 
same  time  under  the  control  and  regulation  of 
muscular  fibre.  These  expansions  are  com- 
posed of  silvery  white  parallel  fibres,  in  many 
places  strengthened  by  bundles  which  cross 
and  interlace  with  the  fibres  last  named,  e.  g. 
the  intercolumnar  bands  at  the  apex  of  the  ex- 
ternal abdominal  ring.  It  is  interesting  to 
notice  that  in  the  larger  quadrupeds,  when  the 
weight  of  the  viscera  is  imposed  on  these 
aponeuroses,  they  are  composed  of  the  yellow 
elastic  fibrous  tissue.  I  have  also  seen  the 
fascia  lata  thus  converted. 

A  second  class  of  these  aponeuroses  consists 
of  those  which  cover  the  soft  parts  in  particular 
regions.  In  general  we  find  that  where  there 
are  many  muscles  covered,  the  aponeurosis 
sends  in  processes  by  which  each  muscle  is 
separately  invested,  these  processes  being  ulti- 
mately inserted  into  the  periosteum  of  the  bone. 
Thus  the  fascia  lata  of  the  thigh  separates  by 
means  of  processes  prolonged  from  its  deep 
surface,  the  various  muscles  to  which  it  forms 
an  external  envelope,  in  such  a  manner  that,  if 
the  muscles  be  carefully  dissected  away  from  a 
thigh,  without  opening  the  fascia  more  than  is 
sufficient  for  their  removal,  it  will  appear  to 
form  a  series  of  channels  in  which  the  muscles 
are  lodged.  A  similar  arrangement  is  found  in 
the  leg  and  foot,  and  in  each  of  the  segments 
of  the  upper  extremity.  The  fascia  lata  has  the 
peculiarity  of  being  in  a  great  degree  influenced 
in  its  tension  by  a  muscle,  called  from  that 


office,  tensor  vagina  J'cmoris,  and  the  fascia 
which  covers  the  palm  of  the  hand  is  likewise 
governed  by  the  palmaris  longus,  the  connec- 
tion of  which,  however,  with  the  fascia  seems 
to  have  reference,  not  to  the  functions  of  the 
fascia,  but  to  the  power  of  the  muscle,  in  aid 
of  the  other  flexors  of  the  wrist;  the  fascia;  of 
the  leg  and  arm  too  receive  the  terminal  expan- 
sion of  the  tendons  of  muscles.  The  strength 
of  these  aponeurotic  sheaths  is  proportionate  to 
the  strength  of  the  muscles  they  cover;  this  is 
apparent,  by  comparing  the  fascia;  of  the  arm 
and  of  the  thigh;  the  strength  of  the  latter 
greatly  exceeds  that  of  the  former,  and  in  the 
thigh  itself  the  vastus  externus  muscle  is  covered 
by  a  portion  of  the  fascia  lata,  much  stronger 
than  those  which  cover  the  muscles  on  its 
posterior  and  inner  aspects. 

In  a  third  class  of  aponeuroses  are  enume- 
rated simple  lamellae  of  fibrous  membrane, 
which  are  found  for  the  most  part  in  connexion 
with  the  walls  of  cavities :  such  are  the  fascia 
transversalis,  connected  with  the  abdomen  ;  the 
fascia  iliaca  and  pelvica,  connected  with  the 
pelvis  ;  and  the  fibrous  expansion  lining  the 
thorax,  which  has  not  received  a  name. 

The  aponeurotic  fasciae  are  most  valuable  in 
their  power  of  resistance,  and  thus  efficacious 
in  maintaining  organs  in  their  proper  situa- 
tions ;  that  they  exert  a  considerable  degree  of 
compression  upon  the  muscles  is  rendered 
evident  by  the  hernia  of  the  muscular  fibres 
which  takes  place  when  an  incision  is  made 
into  the  fascia  lata  of  the  thigh  ;  they  thus  re- 
gulate the  combined  action  of  muscles  and 
render  more  complete  their  isolated  action.  It 
is  incumbent  on  the  surgeon  to  remember  how 
they  confine  purulent  collections  and  oppose 
their  progress  to  the  surface,  a  property  which 
is  likewise  observable  in  the  cellular  fascia?, 
whose  power  of  resistance  is,  however,  much 
less,  but  their  elasticity  much  greater. 

Such  is  a  brief  notice  of  the  generalities  con- 
nected with  the  fascia?  of  the  body :  the  situa- 
tion, connections,  and  structure  of  many  of 
them  are  of  great  interest  to  the  surgical  anato- 
mist, and  will  be  found  fully  detailed  in  the 
articles  devoted  to  the  surgical  anatomy  of 
the  regions.  The  subject  is  also  very  com- 
prehensively treated  in  the  following  works, 
God/nan,  Anatomical  Investigations,  Phila- 
delph.  1824;  Vclpeau,  Anat.  Chirurgicale,  t.  i. 
ed.  2de  ;  Paillard,  Description  complete  des 
Membranes  fibreuses,  Par.  1827  ;  Cruveil/iier, 
Anat.  Descript.  t.  ii.  Aponeurologie,  Par. 
1834  ;  Bourgert/,  Anatomie  de  l'homme,  t.  ii. 

(R.  B.  Todd. J 

FAT.  (o-TEaj,  tti^eAjj,  adeps,  pinguedo; 
Fr.  graissc;  Germ.  Fett;  Ital. grasso.)  Under 
this  term  we  include  a  variety  of  animal  pro- 
ducts which  bear  a  general  resemblance  to 
each  other,  and  to  a  series  of  corresponding 
substances  in  the  vegetable  kingdom  ;  the  fats 
of  animals  being,  like  the  vegetable  oils,  ternary 
compounds  of  carbon,  hydrogen,  and  oxygen, 
and  not,  apparently  in  any  instance,  containing 
nitrogen,  except  as  an  adventitious  or  acciden- 
tal ingredient. 


232 


FAT. 


Fat  is  a  deposition  in  the  cellular  membrane 
of  certain  parts  of  the  body,  especially  under 
the  skin,  in  the  omentum,  in  the  region  of  the 
kidneys,  and  within  the  cylindrical  bones:  it 
also  occurs  here  and  there  among  the  muscles, 
and  sometimes  is  accumulated  to  an  extent  so 
unnatural  as  to  form  a  species  of  disease.  In 
birds  it  is  chiefly  seated  immediately  below  the 
skin,  and  in  water-fowl  it  is  largely  secreted  by 
the  glands  of  the  rump  :  in  the  whale  and  other 
warm-blooded  inhabitants  of  the  deep,  it  is 
chiefly  contained  in  the  head  and  jaw-bones, 
and  abundantly  interposed  between  the  skin  and 
the  flesh ;  in  fish  it  abounds  in  the  liver,  as  in 
the  shark,  cod,  and  ling,  or  is  distributed  over 
the  whole  body,  as  in  the  pilchard,  herring,  and 
sprat. 

Various  opinions  have  been  entertained  re- 
specting the  formation  of  fat,  and  its  insolu- 
bility in  water  has  led  to  the  idea  of  its  produc- 
tion in  the  places  in  which  it  occurs;  but  as  it 
is  found  in  the  blood  and  in  some  other  of  the 
fluids  of  the  body,  it  is  probably  partly  received 
with  the  food,  and  partly  formed  by  the  process 
of  secretion.  Its  remarkable  absorption  in  cer- 
tain cases  of  disease  of  the  chylopoietic  viscera, 
and  of  deficiency  of  proper  food,  seems  to  point 
it  out  as  a  source  of  nutriment  of  which  the  ani- 
mal economy  may  avail  itself  on  emergency  ; 
and  accordingly  in  cases  of  emaciation  or  atro- 
phy, it  is  the  first  substance  which  disappears.  It 
varies  in  consistency  and  characters  in  the  diffe- 
rent tribes  of  animals,  and  in  the  greater  num- 
ber of  amphibia  and  fishes  it  is  usually  liquid  at 
ordinary  temperatures.  (See  AdiposeTissue.) 

The  general  chemical  characters  of  fat  have 
been  long  known,  as  well  as  its  important  pro- 
perty of  saponification  by  means  of  the  alkalis ; 
but  the  real  nature  of  the  changes  which  it  un- 
dergoes in  this  process,  and  the  essential  dis- 
tinctive characters  of  its  varieties,  were  first 
satisfactorily  investigated  by  Chevreul,*  whose 
essay  upon  the  subject  has  been  justly  cited  as 
a -model  of  chemical  research.  It  is  chiefly 
from  this  source,  and  from  the  abstract  of  its 
contents  given  by  Berzelius,f  that  we  have 
taken  the  following  details. 

All  the  varieties  of  fat  are  resolvable  into 
mixtures  of  stearin  and  elain,  (from  cteac^,  suet, 
and  cXukiv,  oil,)  that  is,  into  a  solid  and 
liquid  ;  but  there  are  peculiar  differences  be- 
longing to  these  products  in  each  individual 
species,  which  sometimes  seem  to  depend  upon 
very  trifling  causes,  and  at  others  to  be  con- 
nected with  distinct  ultimate  composition. 

There  are  two  modes  by  which  the  stearin  and 
elain  of  fat  may  be  separated:  the  one  consists 
in  subjecting  it  to  pressure,  (having  previously 
softened  it  by  heat,  if  necessary;)  and  the  other, 
by  the  action  of  boiling  alcohol,  which,  on 
cooling,  deposits  the  stearin,  and  retains  the 
elain  in  solution  ;  the  latter  separates  on  the 
addition  of  water,  still  however  retaining  a 
little  stearin  ;  they  may  be  ultimately  separated 
by  digestion  in  cold  alcohol,  sp.  gr.  .835,  which 

*  Kecherches  chimiqucs  sur  les  corps  gras  d'ori- 
gine  animate.    Paris,  1823. 

t  Lehrbuch  dei  Cheroie.  B.  3  and  4.  Dresden, 
1027. 


takes  up  the  elain,  and  leaves  it  after  careful 
distillation  ;  the  stearin  remains  undissolved. 

Fat  may  be  separated  from  its  associated 
cellular  texture,  by  cutting  it  into  small  pieces 
and  melting  it  in  boiling  water ;  it  collects  upon 
the  surface,  and  when  cold  is  removed,  and 
again  fused  in  a  water-bath,  and  strained 
through  fine  cambric.  Many  varieties  of  fat, 
when  dissolved  in  boiling  alcohol  and  precipi- 
tated by  water,  leave  a  peculiar  and  slightly 
acid  and  saline  extract  in  solution,  apparently 
derived  from  the  enveloping  membranes. 

1.  The  softer  kinds  of  fat  are  termed  lard,  of 
which  hogs-lard  furnishes  a  good  example:  it  is 
white,  fusible  at  a  temperature  between  75° 
and  85°,  and  of  a  specific  gravity  =  about  0.938. 
When  cooled  to  32°,  and  pressed  between  folds 
of  bibulous  paper,  it  gives  out  62  per  cent,  of 
colourless  elain,  which  remains  fluid  at  very 
low  temperatures,  has  a  sp.  gr.  =  .915,  and  is 
soluble  in  less  than  its  weight  of  boiling  alco- 
hol, the  solution  becoming  turbid  when  cooled 
to  about  140°.  The  residuary  stearin  is  ino- 
dorous, hard,  and  granular:  when  fused,  it 
remains  liquid  at  the  temperature  of  100°,  but, 
on  congealing,  it  rises  to  130°,  and  assumes  a 
crystalline  appearance. 

W  hen  hog's-lard  becomes  rancid,  a  pecu- 
liar volatile  acid  forms  in  it,  which  has  not  been 
examined.  100  parts  of  hog's-lard  yield,  when 
saponified,  94.65  margaric  and  oleic  acid, 
which  when  fused  concrete  at  150°;  and  9.  of 
glycerine.  According  fo  Chevreul's  analysis,  the 
ultimate  elements  of  hog's-lard  are — 

Carbon   79.098 

Hydrogen  1 1.146 

Oxygen    9.756 


100.000 


2.  Human  fat  is  another  species  of  lard  ; 
but  it  differs  in  different  parts  of  the  body.  The 
fat  from  the  kidney,  when  melted,  is  yellow, 
inodorous,  begins  to  concrete  at  77°,  and  is 
solid  at  about  60°.  It  requires  40  parts  of 
boiling  alcohol  of  0.841  for  solution,  and  this 
deposits  stearin  as  it  cools,  which,  when  puri- 
fied bv  pressure  between  folds  of  filtering 
paper  at  77°,  is  colourless,  fusible  at  122°,  and 
may  then  be  cooled  down  to  105°,  before  it 
concretes ;  in  the  act  of  concreting  its  tempera- 
ture rises  to  120°,  and  it  becomes  crystalline, 
and  soluble  in  about  four  parts  of  boiling  alco- 
hol, the  greater  part  being  deposited  in  acicular 
crystals  as  the  solution  cools.  The  elain  of 
human  fat,  obtained  by  the  action  of  hot  water 
upon  the  paper  by  which  it  had  been  absorbed, 
is  colourless,  remains  fluid  at  40°,  and  con- 
cretes at  a  lower  temperature.  Its  specific 
gravity  at  60°  is  .913  ;  it  is  inodorous,  and  has 
a  sweetish  taste.  It  is  soluble  in  less  than  its 
weight  of  boiline  alcohol,  and  the  solution  be- 
comes turbid  when  cooled  to  about  62°.  100 
parts  of  human  fat  yield,  when  saponified,  about 
96  of  margaric  and  oleic  acids  fusible  at  about 
90°,  and  from  9  to  10  of  glycerin. 

According  to  Chevreul,  human  fat  and  its 
elain  are  composed  as  follows: — 


FAT. 


233 


FAT. 

Carbon   79.000 

Hydrogen   11.416 

Oxygen    9.584 

100.000 


ELAIN. 

78  566 
11.447 
9.987 

100.000 


3.  The  Jut  of  beef  when  melted  begins  to 
concrete  at  100°:  it  requires  for  solution  40 
parts  of  boiling  alcohol,  and  contains  about 
three-fourths  its  weight  of  stearin,  which  is 
obtained  by  stirring  the  melted  fat  whilst  it  is 
concreting,  and  then  pressing  it  in  woollen 
cloths  at  a  temperature  of  about  95",  by  which 
the  elain  is  squeezed  out,  together  with  a  por- 
tion of  stearin,  which  is  deposited  at  a  lower 
temperature,  for  the  elain  does  not  congeal  at 
32°.  The  stearin  is  white,  granularly  crystal- 
line, fusible  at  112°,  and  may  be  cooled  to  100° 
before  it  congeals,  when  its  temperature  rises  to 
112°.  It  looks  and  burns  like  wax.  100  parts 
of  alcohol  dissolve  15  of  this  stearin  :  when 
saponified,  it  yields  0.95  of  fat  acids,  which 
fuse  at  130°.  The  elain  of  beef  fat  is  colour- 
less and  almost  inodorous,  and  soluble  in  less 
than  its  weight  of  boiling  alcohol.  Candles 
made  of  the  stearin  of  this  fat,  with  a  small 
addition  of  wax  to  destroy  its  brittle  and  crys- 
talline texture,  are  little  inferior  to  wax  candles. 

4.  Neat's  foot  oil  is  obtained  by  boiling  the 
lower  ends  of  the  shin-bones  of  the  ox,  after  the 
removal  of  the  hair  and  hoofs,  in  water.  This 
oil  remains  fluid  below"32°,  and  after  the  sepa- 
ration of  the  stearin,  is  used  for  greasing  turret- 
clocks,  which  are  often  so  exposed  to  cold  as  to 
freeze  other  oils. 

5.  Gout's  fat  is  characterized  by  its  peculiar 
colour,  which  seems  to  depend  upon  the  pre- 
sence of  a  distinct  fatty  matter,  which,  in  the 
separation  of  the  stearin  and  elain,  is  asso- 
ciated with  the  latter,  and  which  Chevreul  has 
called  hircin.  When  the  elain  is  saponified, 
a  liquid  volatile  acid  is  formed,  which  may  be 
separated  as  follows :  four  parts  of  the  fat  are 
made  into  soap  with  one  of  hydrate  of  potassa 
dissolved  in  four  of  water  :  the  soap  is  after- 
wards diluted,  and  decomposed  by  phosphoric 
or  tartaric  acid,  by  which  the  fat  acids  are  sepa- 
rated :  these  are  distilled  with  water,  taking 
care  that  the  contents  of  the  retort  do  not  boil 
over:  the  distilled  liquid  is  saturated  with 
hydjate  of  baryta,  evaporated  to  dryness,  and 
decomposed  by  distillation  with  sulphuric  acid 
diluted  with  its  weight  of  water :  the  acid  is 
separated  in  the  form  of  a  colourless  volatile 
oil  which  floats  upon  the  distilled  liquid ; 
Chevreul  terms  it  hircic  acid:  it  congeals  at 
32°:  it  has  the  odour  of  the  goat,  blended 
with  that  of  acetic  acid  ;  it  reddens  litmus, 
dissolves  difficultly  in  water,  and  readily  in 
alcohol :  it  forms  distinct  salts  with  the  bases  : 
the  salt  of  ammonia  has  a  strong  hircine 
odour :  that  of  potassa  is  deliquescent,  and  that 
of  baryta  difficultly  soluble  in  water. 

6.  Mutton  fat  is  whiter  than  that  of  beef, 
and  acquires  a  peculiar  odour  by  exposure  to 
air;  when  melted  it  begins  to  concrete  at  about 
100°.  It  requires  44  parts  of  boiling  alcohol 
for  solution.    Its  stearin,  when  fused,  begins 


to  congeal  at  100°,  and  its  temperature  rises  on 
solidification  to  113°.  100  parts  of  alcohol 
dissolve  16  of  it.  Its  elain  is  colourless, 
slightly  odorous,  sp.  gr.  0.913,  and  80  parts  of 
it  are  soluble  in  100  of  boiling  alcohol.  When 
saponified,  it  yields  a  very  small  quantity  of 
hircic  acid.  This  species  of  fat,  together  with 
its  stearin  and  elain,  are  composed  as  fol- 
lows : — 

FAT.        STEARIN.  ELAIN. 

Carbon   78.996      78.776  79.354 

Hydrogen  ..11.700  11.770  11.090 
Oxygen   9.304        9.454  9.556 


100.000    100.000  100000 


7.  Whale  oil,  or  train  oil,  (from  whale  blub- 
ber,) sp.  gr.  .927,  when  cooled  to  32°,  deposits 
stearin  ;  the  filtered  oil  is  then  soluble  in  0.82 
of  boiling  alcohol.  Aided  by  heat  it  dissolves 
arsenious  acid,  oxide  of  copper,  and  oxide  of 
lead  ;  sulphuric  and  muriatic  acids  render  the 
latter  combination  turbid,  nitric  acid  tinges  it 
dark  brown  with  effervescence;  and  it  is  coa- 
gulated by  potassa  and  soda.  This  oil  is  easily 
saponified  when  mixed  with  0.6  its  weight  of 
hydrated  potassa,  and  five  parts  of  water ;  the 
soap  is  brown,  soluble  in  water,  and  when  de- 
composed by  tartaric  acid  and  the  sour  liquid 
distilled,  it  yields  traces  of  phoeenic  acid,  also 
glycerine,  and  oleic  and  margarir,  but  no 
stearic  acid :  these  acids  are  accompanied  by  a 
greasy  substance  which  has  the  odour  of  the 
oil.  The  stearic  portion  of  train  oil,  when 
freed  from  adhering  elain  by  washing  with 
weak  alcohol, concretes,  after  having  been  fused, 
at  a  temperature  between  70°  and  80°;  it  is 
soluble  in  1.8  parts  of  boiling  alcohol,  and  is 
deposited  in  crystals  as  it  cools,  leaving  a  dark 
thick  mother-liquor.  When  saponified,  100 
parts  yield  85  of  margaric  and  oleic  acids,  4  of 
a  brown  substance  infusible  at  212°,  and  per- 
fectly soluble  in  boiling  alcohol,  7  of  bitterish 
glycerine,  and  traces  of  phoeenic  acid. 

8.  Spermaceti  oil,  the  produce  of  the  sper- 
maceti whale,*  is  lodged  in  the  cartilaginous 
cells  of  a  bony  cavity  on  the  upper  part  of  the 
head  ;  as  it  cools,  it  deposits  its  peculiar  stearic 
portion  in  the  form  of  spermaceti;  this  sub- 
stance is  further  separated  by  pressure  in  wool- 
len bags  from  the  oil,  and  is  then  washed  with 
a  weak  solution  of  caustic  potassa,  melted  in 
boiling  water,  and  strained;  it  is  commonly 
cast  into  oblong  blocks,  and  if  the  interior 
liquid  portion  is  drawn  off  when  the  exterior 
has  concreted,  the  cavity  exhibits  upon  its  sur- 
faces a  beautiful  crystalline  texture.  Sperma- 
ceti, as  it  occurs  in  commerce,  is  in  semi-trans- 
parent brittle  masses  of  a  foliated  fracture,  and 
soapy  to  the  touch  ;  it  has  a  slight  odour  and  a 
greasy  taste,  and  when  long  kept  becomes  yel- 
lowish and  rancid.  Its  specific  gravity  is  .943; 
it  fuses  at  about  114°.  100  parts  of  boiling' 
alcohol,  sp.gr.  .823,  dissolve  3.5  spermaceti, 
and  about  0.9  is  deposited  on  cooling.  Warm 
ether  dissolves  it  so  copiously,  that  the  solution 
conc-etes  on  cooling;  by  the  aid  of  heat,  it 

*  Physetcr  macrocephalus,  or  Cachalot. 


234 


FAT. 


dissolves  in  the  fat  and  volatile  oils,  and  is  in 
part  deposited  as  the  solution  cools.  Alcohol 
always  extracts  a  small  portion  of  oil  from  the 
spermaceti  of  commerce;  as  the  boiling  alco- 
holic solution  cools,  it  deposits  the  purified 
spermaceti  in  white  crystalline  scales,  and  in 
this  state,  Chevreul  terms  it  cetine.  Cetine 
does  not  fuse  under  120°;  it  forms,  on  cooling, 
a  lamellar,  shining,  inodorous,  and  insipid 
mass,  which  is  volatile  at  high  temperatures, 
and  may  be  distilled  without  decomposition. 
It  burns  with  a  brilliant  white  flame,  and  dis- 
solves in  about  four  parts  of  absolute  alcohol ; 
it  is  very  difficultly  saponified;  digested  for 
several  days  at  a  temperature  between  120°  and 
190°,  with  its  weight  of  caustic  potassa  and  two 
parts  of  water,  it  yields  inargarate  and  oleate  of 
potassa,  and  a  peculiar  fatty  matter,  which 
Chevreul  calls  ethal,*  and  which  amounts  to 
about  40  per  cc7it.  of  the  cetine  used.  To  ob- 
tain it  in  an  insulated  state  the  results  of 
the  saponification  of  cetine  are  decomposed  by 
tartaric  acid,  which  separates  the  margaric  and 
oleic  acid,  together  with  the  ethal ;  the  fat 
acids  are  saturated  with  hydrate  of  baryta,  and 
the  resulting  mixture  well  washed  with  water 
to  separate  all  excess  of  base;  it  is  then  well 
dried,  and  digested  in  cold  alcohol  or  ether, 
which  takes  up  the  ethal  and  leaves  the  barvtic 
salts  ;  the  former  is  then  obtained  by  evapora- 
tion of  the  solvent.  Ethal  is  a  solid,  transpa- 
rent, crystalline,  fatty  matter,  without  smell  or 
taste;  when  melted  alone  it  congeals  at  120° 
into  a  crystalline  cake ;  it  is  so  volatile  that  it 
passes  over  in  vapour  when  distilled  with  yvater. 
It  burns  like  yvax,  and  is  soluble  in  all  propor- 
tions in  pure  alcohol  at  a  temperature  below 
140°.  It  readily  unites  by  fusion  with  fat  and 
the  fat  acids,  and  yvhen  pure  is  not  acted  upon 
by  a  solution  of  caustic  potassa;  but  if  mixed 
with  a  little  soap  it  then  forms  a  flexible  yel- 
lowish compound,  fusible  at  about  145°,  and 
yielding  an  emulsive  hydrate  with  boiling 
water. 

The  ultimate  composition  of  train  oil,  sper- 
maceti oil,  spermaceti,  cetine,  and  ethal,  are 
shewn  in  the  following  tables  : — 


TRAIN  OIL.     SPERMACETI  OIL. 


( 'ai  bon . . 
Hydrogen 
Oxygen. . 


Board. 
.  76.1 
.  12.4 
.11.5 

100.0 


Carbon . . . 
Hydrogen. 
Oxygen  ... 


SPERMACETI. 

Berard. 
...  79.5 
11.6 
8.9 


Ure. 
79.0 
10.5 
10.5 

100.0 


<  F.  IT  N  E. 

Chevreul. 
81.6(50 
12.862 
5.478 


100.0 


100.000 


*  From  the  first  syllables  of  tin-  words  vlher  ami 
alcohol t  in  Consequence  of  a  resemblance  in  ultimate 
composition  to  those  liquids. 


Carbon . .  17 
Hydrogen  18 
Oxygen.  .  1 


ethal.  (Chevreul.) 

Atoms.     £fnjra<«n(>.    Theory.  Erpertmnt. 

102       79.69  79.766 

18        14.06  13.945 

8         6.25  6.289 


128      100.00  100.000 


9.  Phoccnine  is  a  peculiar  fatty  substance 
contained  in  the  oil  of  certain  species  of  por- 
poise ( Delphinus  phocena  and  globiceps). 
When  this  oil  is  saponified,  it  yields  margaric 
and  oleic  acid  and  cetine,  and  a  peculiar  vola- 
tile acid  obtained  by  a  process  similar  to  that 
for  separating  hircic  acid,  and  which  has  been 
termed  phocenic  acid.*  It  is  a  thin,  colourless, 
strong-smelling  oil,  of  a  peculiar  acrid,  acid, 
and  aromatic  taste;  its  specific  gravity  is  .932  ; 
it  does  not  congeal  yvhen  cooled  doyvn  to  14°. 
Its  boiling  point  is  above  212°.  In  this  state 
it  is  an  hydrate,  containing  9  per  cent,  of  water, 
from  which  it  has  not  been  freed.  It  is  solu- 
ble in  all  proportions  in  pure  alcohol. 

The  neutral  salts  of  this  acid  ( plwecnatesj 
are  inodorous,  but  any  free  acid,  even  the  car- 
bonic, in  a  gentle  heat,  evolves  the  odour  of  the 
phocenic  acid.  Heated  in  the  air  they  exhale 
an  aromatic  odour,  dependent  upon  the  forma- 
tion of  a  peculiar  product.  By  dry  distillation 
they  blacken,  evolve  olefiant  gas  and  carbonic 
acid,  and  a  thin,  odorous,  yellow  oil,  insoluble 
in  potassa.  The  pliocenates  of  potassa,  soda, 
and  ammonia,  are  deliquescent ;  the  phocenate 
of  baryta  forms  efflorescent  prismatic  crystals  ; 
and  that  of  lime,  small  acicular  prisms.  The 
neutral  phocenate  of  lead,  evaporated  in  vacuo, 
yields  flexible  lamellar  crystals,  which  are 
fusible  and  easily  become  basic  when  heated  ; 
the  subphocenate  of  lead  is  difficultly  soluble 
and  crystallisable,  and  decomposed  by  the  car- 
bonic acid  of  the  air. 

According  to  Chevreul,  the  anhydrous  pho- 
cenic acid  (as  existing  in  its  anhydrous  salts) 
consists  of 


Atoms. 

Equivalents, 

Theory. 

Experiment. 

Carbon . .  10 

60 

65.93 

65.00 

Hydrogen  7 

7 

7.69 

8  25 

Oxygen . .  3 

24 

26.38 

26.75 

1 

91 

100.00 

100.00 

And  the  oily  hydrated  acid  is  a  compound  of 
1  atom  of  dry  acid  and  1  atom  of  yvater,  or 
91  +  9  =  100. 

10.  The  Jut  of  birds  has  been  but  little  exa- 
mined ;  Chevreul  states  that  the  fat  of  gee* 
concretes  after  fusion  at  about  80°  into  a  gra- 
nular mass  of  the  consistency  of  butter.  Ac- 
cording to  llraconnot  it  yields  by  pressure  at 
32°,  0.68  of  yellowish  elain,  having  the  odour 
and  taste  peculiar  to  this  kind  of  fat,  and  0.32 
of  stearin,  fusible  at  1 10°,  and  soluble  in  rather 
more  than  three  parts  of  anhydrous  alcohol. 
When  saponified,  it  yields  margaric  and  oleic 
acid  and  glycerine. 

•  The  same  acid  is  contained,  according  to 
Chevreul,  in  the  ripe  berries  of  the  Viburnum  ojiutut. 


FEMORAL  ARTERY. 


235 


The  fat  of  the  duck  and  the  turkey  nearly 
esembles  the  above. 

11.  Among  insects,  peculiar  kinds  of  fat 
iave  been  obtained  from  ants,  and  from  the 
ochini  nl  insect.  The  latter  has  been  examined 
>y  Pelletier  and  Caventou.  (Ann.  de  Ch.  et 
'hys.  viii.  271.)  It  is  obtained  by  digesting 
iruised  cochineal  in  ether,  evaporating  and  re- 
issolving  the  residue  in  alcohol,  till  it  remains 
ipon  evaporation  in  the  form  of  colourless 
iearly  scales,  insipid  and  inodorous,  and  fusible 
t  104°. 

12.  Under  the  term  adipocere,  we  have  else- 
where described  a  species  of  fatty  matter  which 
ppears  to  result  from  the  slow  decomposition 
f  fi brine ;  and  in  some  diseased  states  of  the 
iody,  a  large  proportion  of  the  flesh  occasion- 
lly  puts  on  the  appearance  of  fat.  In  the 
i>rmer  case,  it  has  been  supposed  that  the  pro- 
luct  is  the  fat  originally  existing  in  the  body, 
which,  during  the  putrefaction  of  the  other 
larts,  has  become  acidified,  that  is,  converted 
nto  margaric,  stearic,  and  oleic  acids ;  and 
bat  these  acids  are  more  or  less  saturated  by 
lie  ammonia  which  is  at  the  same  time  gene- 
[Ued,  and  by  small  quantities  of  lime  and 
nagnesia  resulting  from  the  decomposition  of 
ertain  salts  of  those  earths  pre-existing  in  the 
nimal  matter.  This  view  of  the  nature  of  adi- 
locere  appears  so  far  correct ;  but  the  quantity 
>f  the  altered  fatty  matter  which  was  found  in 
he  cases  alluded  to,  and  in  others  where  heaps 
•I  refuse  flesh  have  been  exposed  to  humid  pu- 
refaction,  is  sometimes  such  as  to  render  it 
lighly  probable  that  a  portion  of  the  fatty 
natter  is  an  actual  product  of  the  decay,  and 
ot  merely  an  educt  or  residue. 

In  regard  to  the  apparent  morbid  conver- 
ion  of  muscle  into  fat  in  the  living  body, 
Jerzelius  observes  that,  because  the  muscles 
iecome  white,  it  has  been  assumed  that  they 
re  actually  converted  into  fat,  but  that  the 
ppearance  depends  solely  upon  the  absence 
f  red  blood,  for  the  muscles  under  such 
ircumstances  do  not  lose  their  power  of  mo- 
ion.  The  truth  is  that,  in  these  cases,  the 
ccumulation  of  fat  goes  on  to  such  an  extent 
i  the  interstitial  cellular  membrane  of  the 
ruscular  fibre,  as  gradually  to  occasion  its 
lmost  entire  absorption,  and  such  of  the  mus- 
ics as  undergo  this  change  gradually  lose 
leir  contractile  powers.  Two  mutton-chops, 
fhich  have  undergone  this  change,  and  in 
.Inch  the  altered  muscle  and  the  ordinary  ex- 
jrnal  layer  of  adipose  membrane  are  quite  dis- 
nct,  are  preserved  in  the  Museum  of  the 
"ollege  of  Surgeons,  and  there  is  a  printed 
amphlet  giving  an  account  of  the  symptoms 
nder  which  the  sheep  laboured.  What  may 
e  the  chemical  peculiarities  of  the  fat  depo- 
ited  among  the  fibres,  as  compared  with  the 
rdinary  fat,  has  not  been  ascertained. 

The  above  is  an  enumeration  of  such  of  the 
arieties  of  animal  fat  as  have  been  chemically 
xamined.  In  their  general  characters  they 
losely  resemble  the  corresponding  compounds 
f  the  vegetable  kingdom  ;  and,  with  the  exeep- 
ons  specified,  the  process  of  saponification 
Fects  upon  them  very  similar  changes  :  thev 


are  also  similarly  acted  on  by  the  acids.  Some 
of  them  seem  to  afford  distinct  products  when 
subjected  to  destructive  distillation,  and  during 
the  decomposition  of  whale  oil  for  the  produc- 
tion of  carburetted  hydrogen  for  the  purposes 
of  gas  illumination,  a  variety  of  binary  com- 
pounds of  hydrogen  and  carbon,  with  some 
other  products,  are  obtained,  the  nature  of 
which  has  been  ably  investigated  by  Professor 
Faraday.  • 

(  W.  T.  Brande.) 

FEMORAL  ARTERY  (arteria  cruralis; 
Germ,  die  Schenkelarterie ).  The  femoral  ar- 
tery is  the  main  channel  through  which  the 
lower  extremity  is  supplied  with  blood  :  in  an 
extended  sense  it  might,  with  propriety,  be 
understood  to  comprehend  so  much  of  the 
artery  of  the  extremity  as  is  contained  within 
the  thigh,  intermediate  to  those  of  the  abdo- 
men and  the  leg;  but  the  variety  in  the  situ- 
ation and  relations  of  that  vessel  in  different 
stages  of  its  course  is  so  great  that  it  has  been 
distinguished  into  two,  the  proper  femoral 
and  the  popliteal ;  the  former  appellation  being 
applied  to  so  much  of  the  vessel  as  is  situate 
in  the  superior  part  of  the  limb,  and  the  latter 
to  that  portion  which  is  contained  in  the  lower, 
in  the  popliteal  region.  The  comparative  ex- 
tent of  the  two  divisions  of  the  artery  differs 
considerably,  the  femoral  predominating  much 
in  this  respect,  and  occupying  two-thirds  of 
the  thigh,  while  the  popliteal  occupies  but  one; 
hence  the  particular  extent  of  each  may  be 
exactly  defined  by  dividing  the  thigh,  longi- 
tudinally, into  three  equal  parts,  of  which  the 
two  superior  will  appertain  to  the  former,  and 
the  inferior  to  the  latter. 

The  proper  femoral  artery,  then,  engages 
the  two  superior  thirds  of  the  main  artery  of 
the  thigh,  continued  from  the  external  iliac 
artery  above,  and  into  the  popliteal  below.  It 
emerges  from  beneath  Poupart's  ligament  into 
the  thigh,  external  to  the  femoral  vein,  and  on 
the  outside  of  the  ilio-pectineal  eminence  of 
the  os  innominatum,  and  it  passes  into  the 
popliteal  region  below  through  an  aperture  cir- 
cumscribed by  the  tendons  of  the  adductor 
niagnus  and  vastus  internus  muscles.  Its 
course  is  oblique  from  above  downward,  and 
from  before  backward,  corresponding  to  a  line 
reaching  from  a  point  midway  between  the 
anterior  superior  spinous  process  of  the  ilium, 
and  the  symphysis  pubis  upon  the  front  of  the 
limb  above,  to  another  midway  between  the 
two  condyles  of  the  femur,  on  the  posterior 
aspect  of  the  bone  below.  Its  mean  direction 
is  straight,  or  nearly  so,  corresponding  to  the 
line  which  has  been  mentioned,  or,  according 
to  Harrison,-)-  to  a  line  drawn  from  the  centre 
of  Poupart's  ligament  to  the  inner  edge  of  the 
patella;  but  its  course  is,  for  the  most  part, 
more  or  less  serpentine,  the  vessel  forming  as 
it  descends  curvatures  directed  inward  and 
outward.  The  presence  and  degree  of  these 
curvatures,  however,  are  influenced  very  much 

*  Phil.  Trans.  1825. 

t  Surcic.il  Anatomv  of  the  Arteries,  vol.  ii. 
p.  137. 


236 


FEMORAL  ARTERY. 


by  the  state  of  the  vessel  and  by  the  position  of 
the  limb;  when  the  artery  is  empty,  they  are 
less  marked  than  when  it  is  full ;  and  when 
the  limb  is  extended,  they  are  removed;  when 
flexed,  they  are  reproduced  ;  while  in  some 
subjects  again,  they  appear  to  be  absent,  the 
line  of  the  vessel's  course  being  almost  direct. 
The  degree  to  which  the  artery  passes  back- 
ward is  not  equally  great  at  all  parts  of  its 
course:  in  its  upper  half,  i.e.  from  Poupart's 
ligament  until  it  lies  upon  the  adductor  longus 
muscle,  the  vessel  inclines  much  more  back- 
ward than  in  the  remainder,  and  at  the  same 
time  describes  a  curve  concave  forward,  but 
both  the  latter  particulars  are  more  remarkable 
when  the  thigh  is  flexed,  and  in  thin  subjects, 
than  when  the  limb  is  extended  and  in  sub- 
jects which  are  in  good  condition  ;  in  the  last 
case  the  vessel  is  supported  and  held  forward 
by  the  deep  fat  of  the  groin  situate  behind  it. 
In  its  lower  half  the  artery  inclines  less  back- 
ward, being  supported  by  the  muscles  against 
which  it  rests. 

The  femoral  artery  is  also  described  as  in- 
clining inward  *  during  its  descent ;  but  this 
statement  requires  coirection,  or  at  least  ex- 
planation. The  vessel  certainly  does  incline 
inward  at  some  parts  of  its  course,  and  for  the 
most  part  it  does  so  as  it  descends  from  the 
os  innominatum  into  the  inguinal  space,  form- 
ing thereby  the  curvatures  which  have  been 
mentioned ;  but  the  general  direction  of  it  is 
either  slightly  outward,  or  at  the  most  directly 
downward,  not  inward :  the  opinion  that  it  is 
inward  has  arisen,  it  is  to  be  supposed,  from 
a  partial  view  of  its  course,  which,  in  conse- 
quence of  its  serpentine  direction,  is  likely  to 
mislead,  and  is  at  variance  with  that  of  the 
popliteal  artery,  (the  lower  part  of  the  same 
vessel,)  which  is  decidedly  outward.  In  order 
to  be  assured  of  the  true  direction  of  the 
vessel,  the  writer  has  tested  it  carefully  by 
means  of  the  plumb-line,  and  he  has  always 
found  that  it  inclined  somewhat  outward  from 
the  perpendicular :  the  degree,  however,  to 
which  the  proper  femoral  artery  does  so,  is  not 
considerable,  though  sufficient  to  place  the 
matter  beyond  doubt. 

It  is  to  be  borne  in  mind  that,  in  determin- 
ing the  direction  of  the  vessel's  course,  the 
limb  must  be  placed  in  the  bearing  which  it 
holds  naturally  in  the  erect  posture,  inasmuch 
as  an  inclination  to  either  side  will  influence 
materially  the  direction  of  the  artery :  thus  an 
inclination  of  the  limb  inward  will  at  once 
give  it  the  same  tendency,  and  render  it  spiral, 
both  which  conditions  are  removed  by  placing 
the  limb  in  its  ordinary  position. 

In  consequence  of  the  course  which  the 
vessel  pursues,  and  of  the  oblique  position  of 
the  femur  conjointly,  the  femoral  and  popliteal 
arteries  hold  very  different  relations  to  the  shaft 
of  that  bone  ;  the  former,  in  the  first  stage  of 
its  course,  being  in  a  plane  anterior  to  the 
femur,  and  in  the  middle  of  the  limb  being 
upon  its  inside;  while  the  latter  is  situate  be- 
hind the  bone,  and  at  the  inferior  part  of  the 

*  Uoycr,  Clo(]ucl,  Harrison. 


popliteal  region  corresponds  to  the  axis  of  its 
shaft:  hence  the  artery  is  said*  to  pass  some- 
what in  a  spiral  manner  in  reference  to  the 
thigh  bone ;  but  this  is  incorrect,  the  spiral 
course  being  only  apparent  and  resulting  from 
the  combined  effect  of  the  obliquity  of  the 
artery  itself  backward  and  outward,  and  of  the 
shaft  of  the  femur  inward  and  forward  :  that 
this  is  so  may  be  satisfactorily  shewn  by  the 
application  of  the  plumb-line  to  the  course  of 
the  artery,  upon  the  different  aspects  of  the 
limb;  from  which  it  will  appear  that,  allow- 
ance being  made  for  the  serpentine  deviations 
already  adverted  to,  the  general  course  of  the 
vessel  is,  quum  proximi,  straight,  and  that  it 
cannot,  at  all  with  propriety,  be  said  to  be 
spiral,  this  being  not  a  real  but  an  apparent 
direction,  the  result  of  the  circumstances  which 
have  been  mentioned. 

The  point  at  which  the  femoral  artery  com- 
mences is  referred  by  most  writers  to  Poupart's 
ligament;  this  method  of  demarcation  is  at- 
tended with  the  inconvenience,  that  during  life 
the  exact  situation  of  the  ligament  is  difficult 
to  determine,  inasmuch  as  it  does  not  run 
direct  from  one  attachment  to  the  other,  and 
that  in  dissection  its  position  is  immediately 
altered  on  the  division  of  its  connections  with 
the  adjoining  fascia-:  hence  the  student,  not 
having  a  fixed  point  of  reference,  is  often  at  a 
loss  to  distinguish  between  the  iliac  and  femo- 
ral arteries,  and  mistakes  affecting  the  relations 
of  the  most  important  branches  of  those  vessels 
are  liable  to  be  made.  For  those  reasons  it 
appears  to  me  that  it  would  be  much  pre- 
ferable to  select  some  fixed  and  unchanging 
point  to  which  to  refer  the  commencement  of 
the  artery ;  and  for  this  purpose  I  would 
suggest  the  ilio-pectineal  eminence  of  the  os 
innominatum,  which,  to  the  student  at  least, 
if  not  to  the  practical  surgeon,  will  afford  an 
unerring  guide  to  the  distinction  of  the  one 
vessel  from  the  other;  the  femoral  artery,  at 
its  entrance  into  the  thigh,  being  situate  im- 
mediately external  to  the  inferior  part  of  that 
prominence,t  with  which  point  the  middle  of 
the  line  connecting  the  anterior  superior  spi- 
nous process  of  the  ilium  and  the  symphysis 
of  the  pubis  will  also  be  found  to  correspond. 
The  precise  situation  of  the  vessel  is  referred 
by  some  to  the  centre  of  Poupart's  ligament, 
or  a  point  midway  between  the  anterior  supe- 
rior spinous  process  of  the  ilium  and  the 
spinous  process  of  the  pubes ;  by  others  to  a 
point  midway  between  the  spinous  process  of 
the  ilium  and  the  symphysis  of  the  pubes. 
With  regard  to  this  question  it  is  to  be  ob- 
served that  the  relation  of  the  artery  to  the 
points  between  which  it  is  situate  is  not  strictly 
the  same  in  all  instances ;  that  in  some  it  will 
be  found  to  correspond  to  the  former,  and  in 
others  to  the  latter  account;  but  that  the  latter 
relation  appears  to  prevail  in  so  much  the 
greater  number,  that  it  ought  to  be  adopted  as 
the  rule.  According  to  Velpeau  it  is  distant 
two  inches  and  a  quarter  from  the  spinous  pro- 

*  Harrison,  op.  cit.  p.  137. 

t  This  point  will  be  discussed  again. 


FEMORAL  ARTERY. 


cess  of  the  pubes,  and  from  two  and  a  half  to 
two  and  three  quarters  from  the  superior  an- 
terior spinous  process  of  the  ilium. 

The  femoral  artery  is  attended  through  its 
entire  course  by  the  femoral  vein,  the  two 
vessels  lying  in  apposition  and  inclosed  within 
a  fibro-cellular  investment,  to  which  the  ap- 
pellation femoral  sheath  will  be  applied.  It 
is  also  related  to  the  crural  nerve  or  its  branches, 
and  it  is  contained,  together  with  the  vein,  in 
a  canal  of  fascia,  which  will  be  denominated 
the  ft  moral  canal. 

It  is  necessary  to  dwell  here,  for  a  little, 
upon  the  distinction  between  the  two  appel- 
lations  femoral  canal  and  femoral  sheath,  that 
a  confusion  of  the  one  with  the  other  may  not 
arise.    The  vessels  have  in  fact,  throughout 
their  course,  two  distinct  sheaths,  which  may 
be  considered  peculiar  to  them,  contained  the 
one  within  the  other :  the  external  is  formed 
by  the  fascia  lata  in  a  manner  to  be  presently 
explained,  and  is  in  all  respects  analogous  to 
the  canal  furnished  by  the  cervical  fascia  to 
the  carotid  artery  and  jugular  vein.  This  outer 
sheath,  which  many  may  regard  as  the  sheath 
of  the  vessels,  extends  from  Poupart's  liga- 
ment to  the  aperture  by  which  they  escape  into 
the  popliteal  region,  and  will,   for  reasons 
which  will  appear  more  fully  by-and-bye,  be 
here  called  the  femoral  canal.    The  second  or 
internal  sheath  is  situate  within  the  former, 
is  of  variable  thickness,  according  to  the  point 
at  which  it  may  be  examined,  being  for  the 
most  part  very  thin;  adheres  in  general  closely 
to  the  vessels,  in  which  particular  it  differs  from 
the  outer  one,  within  which  they  are  com- 
paratively free ;  and  not  only  covers,  but  also 
separates  them  by  a  thin  internal  process, 
which  by  its  density  and  intimate  adhesion  to 
the  vessels  connects  them   straitly  to  each 
other;  it  is  further  not  confined,  as  the  other  is, 
to  the  vessels,  while  called  femoral,  but  is 
prolonged  upon  them  into  the  popliteal  region, 
where  in  like  manner  it  invests  and  connects 
them :  to  this  investment  the  denomination 
femoral  sheath  will  be  applied.    A  distinction 
between  the  two  structures  is  necessary  in  a 
description   of  the  relations  of  the  femoral 
artery,  were  it  only  to  mark  their  existence, 
but  that  which  I  have  adopted  is  rendered 
imperative  by  the  use  already  made  of  the 
latter  appellation  with  reference  to  the  anatomy 
of  hernia,  in  the  history  of  which  it  is  ap- 
plied not  to  the  canal   as  formed  by  the 
fascia  lata,  but  to  that,  through  which  the 
femoral  vessels  escape  from  the  abdomen,  and 
as  formed   by  the  fascia?  transversalis  and 
iliaca;  and  the  prolongation  of  the  former  of 
these  two  fasciae  being,  in  my  opinion,  con- 
tinued into  the  internal  and  immediate  in- 
vestment of  the  vessels,  it  has  appeared  to  me 
justifiable  to  extend  the  signification  of  the 
title  femoral  sheath,  and  to  apply  it  to  that 
investment  throughout  their  entire  course,  as 
well  below  as  above  the  saphenic  opening  of 
the  fascia  lata;  while  his  application  of  the 
former  appellation,  femoral  canal,    is  sanc- 
tioned by  Cloquet,  by  whom  it  is  used  in  the 
same  sense. 


Beside  those  which  have  been  already 
mentioned,  the  femoral  artery  has  also, 
during  its  course,  the  following  general  re- 
lations : — posteriorly  it  corresponds  in  suc- 
cession to  the  psoas  magnus,  the  pectinalis, 
the  adductor  brevis,  adductor  longus  and  ad- 
ductor magnus  muscles;  anteriorly  it  is,  in 
the  first  part  of  its  course,  not  covered  by 
any  muscle  and  is  comparatively  superficial  ; 
and  through  the  remainder  and  more  exten- 
sive portion  it  is  covered  by  the  sartorius. 
Externally  it  corresponds  to  the  psoas  and 
iliacus,  to  the  sartorius,  the  rectus,  and  lastly 
to  the  vastus  internus  muscles ;  the  latter  of 
which  is  interposed  between  it  and  the  inside 
of  the  femur:  internally  it  corresponds  to 
the  pectinalis  and  the  adductor  longus  mus- 
cles ;  and  lastly  it  is  overlapped  by  the  sar- 
torius. 

It  is  contained,  through  its  upper  half,  in 
the  inguinal  region.  This  region  is  of  a 
triangular  prismatic  form,  the  base  of  the 
triangle  represented  by  it  being  above  formed 
by  Poupart's  ligament,  or  by  a  line  connecting 
the  anterior  superior  spinous  process  of  the 
ilium  and  the  symphysis  pubis;  its  apex 
below  by  the  meeting  of  the  sartorius  and 
the  adductor  longus  muscles.  The  sides  of 
the  prism  are  external  and  internal,  inclined, 
the  former  backward  and  inward,  the  latter 
backward  and  outward,  and  meeting  each 
other  along  the  internal  and  posterior  side 
of  the  femur;  they  are  formed,  the  external 
by  the  iliacus  and  psoas,  the  rectus,  the  vastus 
internus  and  the  sartorius  muscles,  and  the 
internal  by  the  pectinalis  and  the  adductors. 
The  base  of  the  prism  is  in  front,  consisting 
of  the  coverings  of  the  space.  During  its 
descent  from  the  os  innominatum  into  the 
inguinal  region,  the  artery  generally  inclines 
inward,  describing  a  curve  convex  out- 
ward ;  and  hence,  as  it  seems  to  me,  the 
entire  course  of  the  vessel  has  been  assumed 
to  be  inward ;  but  this  first  curve,  when 
present,  is  soon  compensated  by  another  in 
the  opposite  direction.  In  its  lower  half  the 
artery  is  enclosed  between  muscles,  the  vastus 
internus  upon  its  outside,  the  adductors  longus 
and  magnus  behind  it,  and  the  sartorius  in 
front. 

The  course  of  the  femoral  artery  may  be 
advantageously  divided  into  three  parts  or 
stages,  to  be  distinguished  as  first,  second, 
and  third,  or  as  superior,  middle,  and  inferior 
thirds  ;  in  each  of  which  will  be  found  such 
peculiarities  in  the  relations  of  the  vessel  as 
will  justify  the  number  of  subdivisions.  They 
may  be  defined  with  sufficient  precision  by 
dividing  the  two  superior  thirds  of  the  thigh 
into  three  equal  parts,  and  they  will  occupy 
each,  according  to  the  stature,  from  three  to 
five  inches. 

The  superior  stage  reaches  from  Poupart's 
ligament  to  the  point  at  which  the  artery 
is  first  covered  by  the  sartorius  :  during  this 
its  upper  third,  the  vessel  is  not  covered  by 
muscle,  except  at  its  termination,  where  it 
is  overlapped  by  the  inner  margin  of  the 
sartorius  :  it  is  therefore  comparatively  super- 


238 


FEMORAL  ARTERY. 


ficial,  and  its  pulsations  can  be  felt  during 
life  with  greater  or  less  facility  according  to 
circumstances,  to  be  explained.  It  has,  how- 
ever, four  structures  interposed  between  it  and 
the  surface,  and  forming  its  coverings ;  viz. 
the  skin,  the  subcutaneous  cellulai  stratum, 
the  anterior  wall  of  the  femoral  canal,  and  the 
prolongation  of  the  fascia  transversalis  or  the 
femoral  sheath. 

The  subcutaneous  cellular  structure  pre- 
sents a  remarkable  difference  according  to  the 
condition  of  the  subject  or  certain  other  cir- 
cumstances. When  the  body  is  devoid  of 
fat  or  emaciated,  this  structure  appears  a  thin, 
condensed,  dry  and  lamelliform  stratum,  con- 
tinued from  the  abdomen  downward  upon  the 
lower  extremity,  and  generally  denominated 
the  superficial  fascia  of' the  thigh;  but  when, 
on  the  contrary,  the  body  is  in  good  condition, 
and  the  quantity  of  superficial  adeps  is  con- 
siderable, the  appearance  of  a  membranous 
expansion  is  removed,  and  in  its  stead  a 
thick  and  uniform  stratum  of  fat  is  found  in- 
terposed between  the  skin  and  the  fascia  lata. 
In  other  cases  presenting  a  medium  condition, 
the  stratum  of  fat  and  the  membranous  expan- 
sion may  be  both  observed  :  in  such  case  the 
former  is  generally  superficial,  and  the  latter 
underneath;  but  when  the  accumulation  of 
adeps  in  the  subcutaneous  structure  is  more 
considerable,  e.  g.  in  the  healthy  infant  or  in 
many  adults,  particularly  among  females,  no 
trace  of  superficial  fascia  is  to  be  found.  So 
much  for  the  varieties  which  the  subcutaneous 
cellular  structure  presents  naturally.  It  is 
also  found  frequently  in  abnormal  conditions 
deserving  of  attention  :  at  times  it  is  divisible 
to  a  greater  or  less  extent  into  a  succession  of 
expansions,  having  each  the  appearances  of 
fasciae  and  being  of  indeterminate  number : 
this  disposition,  which  occurs  not  unfrequently, 
and  is  of  considerable  importance  in  a  practical 
point  of  view,  appears  due  to  the  influence 
of  pressure  exerted  by  tumours,  e.  g.  that  of 
hernia.  Again,  in  anasarca  the  subcutaneous 
structure  becomes  greatly  increased  in  depth, 
and  loses  all  appearance  of  membrane,  seeming 
then  a  deep  gelatinous  stratum,  consisting  of 
the  cellular  structure  and  the  effused  serum. 

The  depth,  therefore,  of  the  femoral  artery 
from  the  surface,  and  the  number  of  coverings 
which  it  may  have  in  individual  cases,  must 
be  materially  influenced  by  those  several  con- 
ditions of  the  subcutaneous  cellular  structure 
when  present,  and  they  should  never  be  lost 
sight  of;  else  uncertainty  and  embarrassment 
must  arise  in  the  conduct  of  operations.  It 
is  further  to  be  borne  in  mind  that  the  account 
of  the  coverings  of  the  artery  given  in  this 
description  has  reference  to  the  natural  and 
most  simple  arrangement  of  those  structures. 
The  subcutaneous  structure  also  encloses  within 
it  the  superficial  vessels,  nerves,  and  glands, 
the  relation  of  some  of  which  to  the  artery 
requires  notice.  The  superficial  vessels  are 
the  saphena  vein,  the  superficial  femoral  veins, 
and  those  veins  and  arteries  by  which  the 
inguinal  glands  are  supplied. 

The  saphena  vein  ascends,  from  the  inner  and 


back  part  of  the  knee,  along  the  inner  and  an- 
terior aspects  of  the  thigh  to  its  upper  extre- 
mity, where  it  joins  the  femoral  vein  upon 
its  anterior  and  internal  side,  at  the  distance 
of  from  one  inch  to  an  inch  and  a  half  below 
Poupart's  ligament.  During  its  ascent  the 
vein  passes  forward  and  outward,  and  is  situate 
internal  to  the  femoral  artery :  at  the  lower 
extremity  of  the  middle  third  of  the  thigh, 
(the  point  at  which  the  artery  is  about  to  pass 
into  the  ham,)  it  is  placed  superficial  to  the 
vessel,  between  it  and  the  internal  surface  of 
the  limb,  near  to  the  inner,  or  at  this  part  the 
posterior  margin  of  the  sartorius  muscle  ;  but 
as  the  vein  ascends,  the  distance  between  the 
vessels  increases,  partly  because  of  the  greater 
width  of  the  thigh  at  its  upper  part,  and 
partly  because  the  course  of  the  vein  describes 
a  curve  convex  inward  ;  and  at  the  termination 
of  the  latter  it  amounts  to  the  width  of  the 
femoral  vein  or  somewrhat  more ;  lower  down 
it  is  still  greater  in  consequence  of  the  curve 
formed  by  the  saphena.  Hence,  in  operations 
upon  the  superior  part  of  the  artery,  the 
saphena  ought  to  be  exempt  from  danger ; 
while  at  the  lower  part  it  must  be  very  much 
exposed,  if  the  inner  margin  of  the  sartorius 
be  cut  upon  as  the  guide  to  the  vessel. 

The  superficial  femoral  veins  next  claim 
attention :  they  are  very  irregular  in  their 
course  and  destination,  and  therefore  are  the 
moie  likely  to  prove  a  source  of  embarrass- 
ment in  operation.  They  are  smaller  than  the 
saphena,  but  yet  are  in  many  cases  of  con- 
siderable size :  they  present,  according  to  the 
subject,  two  dispositions;  either  they  join 
the  saphena  during  its  ascent  at  variable  points 
in  the  course  of  the  thigh,  and  in  such  case 
cross  the  limb  and  the  artery  obliquely  from 
without  inward,  at  different  heights  ;  or  they 
form  one  or  two  considerable  vessels,  which 
ascend  external  to  the  saphena,  and  open  into 
the  femoral  vein  hi  front,  at  the  same  time 
with  the  former  vessel,  passing  through  the 
superficial  lamina  of  the  fascia  lata  in  the 
same  manner  as  it  does.  When  there  are 
two  such  veins,  the  inner  one  is  generally 
situate  internal  to  the  artery,  between  it  and 
the  saphena,  and  consequently  very  near  to 
it ;  while  the  external  one,  or  the  vein,  if 
there  be  but  one,  runs  upward  and  inward, 
and  crosses  the  artery  in  its  upper  thi.d, 
between  the  point  at  which  the  saphena  joins 
the  femoral  vein  and  that  at  which  the  artery 
is  overlapped  by  the  sartorius :  the  last-de- 
scribed vein,  when  present,  must  obviously 
be  much  endangered  i:i  exposing  the  femoral 
artery  at  this  part  of  its  course,  and  perhaps 
is  the  vessel  which  has  given  rise  to  the  idea 
that  the  saphena  itself  may  be  encountered  in 
cutting  upon  the  artery  in  this  situation. 

The  superficial  inguinal  glands  are  distin- 
guished into  two  sets,  a  superior  and  an  in- 
ferior: those  of  the  former  are  more  numerous, 
and  nearer  to  the  integuments  than  the  latter. 
They  are  ranged  immediately  below  l'oupart's 
ligament,  having  their  longer  diameter  parallel 
to  it,  and  in  greatest  number  superficial  to 
that  part  of  the  iliac  portion  of  the  fascia  lata, 


FEMOKAI-  ARTERY. 


239 


which  is  called  its  cribriform  portion,  and 
over  the  course  of  the  femoral  artery,  across 
which  they  are  placed  obliquely :  they  are 
separated  from  the  vessel  hy  the  superficial 
lamina  of  the  iliac  portion  of  the  fascia,  and 
by  the  prolongation  of  the  fascia  transversal  is, 
with  the  interposed  cellular  structure;  and 
they  derive  numerous  arterial  and  venous 
branches  from  the  main  trunks  bene  ath  :  those 
branches,  which  are  given  off  partly  by  the 
vessels  themselves,  and  partly  by  their  super- 
ficial pudic,  superficial  epigastric,  and  su- 
perficial anterior  iliac  branches,  pass  through 
the  interposed  structures  in  order  to  reach 
the  glands;  in  doing  so  they  carry  with  them 
sheaths  from  the  fascia  lata,  which  is  prolonged 
upon  each  as  it  <  scapes,  and  thus  they  become 
the  means  of  establishing  that  connection  be- 
tween the  fascia  in  the  groin  and  die  subcu- 
taneous stratum,  in  which  the  glands  are 
enveloped,  which  is  considered  to  influence 
so  remarkably  the  course  of  femoral  hernia. 
The  glands  of  the  second  set  are  less  nu- 
merous, are  situate  farther  from  Poupart's 
ligament  than  the  former,  being  below  the 
entrance  of  the  saphena  ;  they  are  also  deeper 
seated,  lying  upon  the  fascia  lata,  and  they 
are  placed  with  their  longer  diameter  parallel, 
or  nearly  so,  to  the  femur  and  to  the  course 
of  the  artery.  Their  relation  to  the  artery  is 
not  in  all  cases  the  same,  inasmuch  as  the 
disposition  of  neither  part  is  strictly  uniform, 
hut  usually  one  or  two  of  them  lie  over  the 
vessel,  or  immediately  on  either  side  of  its 
course;  their  relation  to  it,  however,  is,  in 
the  natural  condition  of  the  parts,  not  of  great 
consequence;  for  in  such  case  they  may  be 
easily  held  aside  during  operation  if  necessary, 
and  thus  both  they  and  their  lymphatic  vessels 
be  saved  from  injury. 

The  relation  of  the  inguinal  glands,  more 
particularly  the  superior,  to  the  femoral  artery 
suggests  several  inferences.  1st,  That  the 
very  commencement  of  the  artery's  course, 
although  the  situation  in  which  the  vessel  is 
nearest  to  the  surface,  and  that  in  which  it 
can  be  most  easily  distinguished  by  its  pulsa- 
tion, is  yet  not  the  most  eligible  part  at  which 
to  expose  it,  since  the  glands  and  their  vessels 
cannot,  by  any  precaution  of  the  surgeon,  be 
protected  certainly  from  injury.  2dly,  That 
phagedenic  ulceration  of  the  glands  of  the 
groin  must  be  attended  with  great  danger  from 
the  vicinity  of  the  great  vessels.  3dly,  That 
hemorrhage  consequent  upon  such  ulceration 
does  not  necessarily  proceed  from  those  vessels 
themselves;  but  that  it  may,  and  in  the  ma- 
jority of  cases  in  the  first  instance  probably 
does  arise  from  the  branches  supplying  the 
glands  ;  and,  4th,  That  the  groin  is  likely  to  be 
the  seat  of  pulsating  tumours  requiring  to  be 
distinguished  from  aneurism. 

The  third  covering  of  the  artery  is  the 
superficial  lamina  of  the  iliac  portion  of  the 
fascia  lata.  This  portion  having  covered  the  an- 
terior surface  of  the  iliacus  and  psoas  muscles 
as  far  as  the  middle  of  Poupart's  ligament, 
along  which  it  is  attached  from  without  inward, 
divides  at  that  point  into  two  laminae,  a  deep 


one  and  a  superficial  one;  the  former  passes 
inward  and  backward  from  the  ligament,  upon 
the  psoas  muscle,  to  the  ilio-pectineal  eminence 
of  the  os  innominatum,  into  which  it  is  in- 
serted, continued  thence  upward,  upon  the 
inside  of  the  muscle,  along  the  brim  of  the 
pelvis  into  the  fascia  iliaca,  and  downward 
across  the  capsule  of  the  ilio-femoral  articula- 
tion, to  which  it  is  also  attached  :  it  is  in 
fact  that  part  of  the  fascia  iliaca,  (for  the  fascia 
iliaca  and  the  iliac  portion  of  the  fascia  lata 
are  one  and  the  same  expansion,  distinguished 
from  each  other  only  by  Poupart's  ligament,) 
which  is  situate  upon  the  inside  of  the  psoas 
magnus,  and  which  forms  the  outer  wall  of 
the  femoral  canal,  being  interposed  between  the 
femoral  artery  and  the  muscle.  At  the  iho- 
pectineal  eminence  it  also  meets  and  is  iden- 
tified with  the  pubic  portion  of  the  fascia 
lata,  which  is  attached  to  the  pectineal  line 
of  the  pubis,  in  continuation  with  this  deep 
lamina  of  the  iliac  portion,  covers  the  pectinalis 
muscle,  and  is  situated  immediately  behind 
the  vessels.  When  that  part  of  the  deep 
lamina  of  the  iliac  portion  of  the  fascia  lata 
which  extends  from  Poupart's  ligament  to  the 
ilio-pectineal  eminence  has  had  the  prolonga- 
tion of  the  fascia  downward  detached  from  it, 
it  appears  as  an  oblique  partition  dividing 
the  crural  arch  into  two  parts,  an  external 
containing  the  iliacus  and  psoas  muscles  with 
the  crural  nerve,  and  an  internal  containing 
the  femoral  vessels. 

The  second  lamina  of  the  iliac  portion  of 
the  fascia  lata— the  superficial  one  —  passes 
inward  across  the  femoral  vessels,  superficial 
to  them  and  to  the  prolongation  of  the  fascia 
transversalis,  until  it  has  reached  the  inside 
of  the  vessels  :  it  is  at  the  same  time  attached 
above,  in  front  of  the  vessels,  and  in  con- 
tinuation with  the  iliac  portion  itself,  to  the 
inferior  margin  of  Poupart's  ligament,  from 
its  middle  to  the  base  of  its  third  insertion — 
Gimbernat's  ligament,  and  upon  their  inside 
along  the  base  of  the  latter  ligament  as  far 
as  the  pectineal  line  of  the  pubis,  into  which 
it  is  finally  inserted,  external  to  the  base  of 
Gimbemat,  between  it  and  the  insertion  of 
the  fascia  transversalis  upon  the  inside  of  the 
aperture  of  the  femoral  sheath,  and  where 
it  is  also  identified  with  the  pubic  portion 
of  the  fascia  attached  along  the  same  line  : 
from  thence  it  is  united  to  the  anterior  surface 
of  the  pubic  portion  of  the  fascia  lata,  down- 
ward along  the  inside  of  the  vessels.  The 
superficial  lamina  of  the  iliac  portion  is  thus 
thrown  across  the  front  of  the  vessels,  and 
by  the  disposition,  which  has  been  detailed, 
the  fascia  lata  encloses  the  vessels  between  the 
two  laminae,  and  forms,  by  means  of  them 
and  their  connection  at  either  side,  a  canal, 
within  which  are  contained  the  vessels  and 
the  prolongation  of  the  fascia  transversalis 
covering  them  in  front.  The  constitution  of 
the  canal,  as  described,  may  be  considered 
to  extend  from  Poupart's  ligament  until  the 
artery  is  about  to  be  covered  by  the  sartorius; 
from  whence  its  anterior  wall  is  formed,  through 
the  remainder  of  the  vessel's  course,  by  another 


240 


FEMORAL  ARTERY. 


anil  deeper  layer  of  the  fascia.  The  canal 
thus  formed,  to  which  the  author  would  apply, 
with  Cloquet,  the  term  femoral  canal,  is 
widest  at  its  upper  extremity,  i.  e.  at  Poupart's 
ligament ;  from  whence,  as  it  descends,  it 
contracts  in  width  until  it  has  passed  the 
entrance  of  the  saphena,  beyond  which  it 
continues  of  nearly  uniform  capacity  to  its 
termination.  The  diminution  in  the  transverse 
extent  of  the  canal  is  due  to  the  direction 
of  the  line  of  union  between  the  superficial 
lamina  of  the  iliac  portion  and  the  pubic 
portion  of  the  fascia,  which,  as  has  been 
already  stated,  inclines  outward  as  it  descends 
from  the  pectineal  line  of  the  pubis  to  the 
point  at  which  the  saphena  joins  the  femoral 
vein.  In  the  interval  between  Poupart's 
ligament  and  the  junction  of  the  two  veins 
the  superficial  lamina  is  thinner,  less  aponeu- 
rotic, and  more  of  a  cellular  character  than 
other  parts  of  the  fascia ;  but  it  is  subject  to 
much  variety  in  this  respect :  in  all  cases  it 
is  thinner  and  weaker  internally  than  externally, 
but  in  some  it  is  throughout  distinct  and  un- 
broken, unless  by  the  passage  of  vessels,  and 
presents  aponeurotic  characters  as  decidedly  as 
many  other  parts  of  the  expansion ;  while  in 
others  it  is  cellular,  indistinct,  and  even  fatty, 
not  easily  distinguishable  from  the  subcuta- 
neous structure,  and  so  thin  as  to  seem  de- 
ficient toward  its  inner  part,  or  to  have  its 
line  of  union  with  the  pubic  portion  inter- 
rupted at  one  or  more  points.  The  extent 
and  connections  of  this  portion  of  the  fascia 
will  be  most  satisfactorily  displayed  by  first 
detaching  Poupart's  ligament,  upon  its  abdo- 
minal side,  from  the  fascia  transversalis  as  it 
descends  beneath  the  ligament,  and  then  care- 
fully insinuating  the  handle  of  a  knife  down- 
ward beneath  the  ligament  and  the  superficial 
lamina  of  the  iliac  portion  of  the  fascia  lata, 
between  them  and  the  prolongation  of  the 
fascia  transversalis :  this  done,  the  superficial 
lamina  may,  with  the  guidance  of  the  instru- 
ment beneath  it,  be  satisfactorily  traced. 

The  fourth  structure,  by  which  the  femoral 
artery  is  covered  in  the  first  stage  of  its  course, 
is  the  prolongation  of  the  fascia  transversalis. 
The  two  abdominal  fascia?,  the  transversalis 
and  the  iliaca,  which  are,  at  every  other  part 
of  the  crural  arch,  either  identified  and  united, 
or  inserted  into  bone,  are  separated  in  the  in- 
terval between  the  middle  of  Poupart's  and 
the  base  of  Gimbernat's  ligament,  and  de- 
scend into  the  thigh,  the  former  in  front  of  or 
superficial  to  the  femoral  vessels,  beneath  Pou- 
part's ligament  and  the  superficial  lamina  of 
the  iliac  portion  of  the  fascia  lata ;  the  latter 
behind  or  deeper  than  the  vessels,  between 
them  and  the  psoas  and  pectinalis  muscles, 
constituting  or  continued  into  the  pubic  or 
deep  portion  of  the  fascia  lata.  The  two  fascia; 
thus  leave  an  aperture  beneath  Poupart's  liga- 
ment, through  which  the  vessels  escape  from 
the  abdomen,  and  at  the  same  time  inclose 
them  between  them ;  the  prolongation  of  the 
transversalis  covering  them  in  front,  the  iliac 
and  pubic  portion  of  the  fascia  lata  situate 
behind  them.    As  it  descends  upon  the  vessels, 


the  prolongation  from  the  transversalis  is  united 
to  the  fascia  iliaca  and  iliac  portion  of  the 
fascia  lata  upon  their  outside  ;  and  to  the  pubic 
portion  upon  their  inside,  in  the  same  manner 
as  the  superficial  lamina  of  the  iliac  portion, 
and  within  it  in  reference  to  the  femoral  canal : 
it  may  therefore  be  viewed  in  one  of  two  lights 
with  regard  to  that  canal,  viz.  either  as  de- 
scending into  it  superficial  to  the  vessels,  and 
entering  into  the  constitution  of  its  anterior 
wall,  or  as  concurring  with  the  other  fasciae  to 
form,  beneath  the  superficial  lamina  of  the 
iliac  portion  of  the  fascia  lata,  a  sheath,  in 
which  the  vessels  are  immediately  contained. 
The  latter  is  the  view  which  has  been  adopted 
by  anatomists,  and  the  appellation  femoral  has 
been  given  to  the  sheath  so  formed.  Like  the 
superficial  lamina  of  the  iliac  portion  of  the 
fascia  lata,  the  prolongation  of  the  fascia  trans- 
versalis is  wider  at  Poupart's  ligament,  and 
diminishes  in  w  idth  as  it  descends  to  the  junc- 
tion of  the  saphena  and  femoral  veins :  hence 
the  femoral  sheath  is  considerably  larger  supe- 
riorly than  inferiorly,  does  not  embrace  the 
vessels  closely  at  their  entrance  into  the  thigh, 
and  but  for  the  aponeurotic  expansion  described 
by  Colles,  and  termed  by  Cloquet  the  crural 
septum,  would  be  open  toward  the  abdomen  ; 
but  in  proportion  as  they  descend,  it  invests 
them  more  closely  until  it  reaches  the  entrance 
of  the  saphena,  at  which  point  its  connection  to 
them  is  intimate,  and  from  whence  the  prolon- 
gation seems  to  the  author  to  be  continued  down- 
ward into  the  dense  thin  cellular  or  fibro-cellular 
investment,  by  which  the  artery  and  vein  are 
surrounded  and  connected  together  within  the 
femoral  canal  during  the  remainder  of  their 
course  through  the  thigh.  From  Sir  A.  Coo- 
per's account  of  the  prolongation  it  would 
appear  that  it  terminated,  or  cannot  be  traced 
further  than  two  inches  below  Poupart's  liga- 
ment. Sir  Astley  says,  "  these  vessels  pass 
down  within  the  sheath  for  about  two  inches, 
after  which  they  carry  with  them  a  closely 
investing  fascia  derived  from  the  fascia  lata." 
By  the  "  closely  investing  fascia,"  the  author 
understands  the  proper  sheath  of  the  vessels, 
which  has  been  adverted  to,  and  with  which 
the  prolongation  of  the  fascia  transversalis 
appears  to  him  to  be  identified.  According  to 
Professor  Harrison,*  "  it  soon  becomes  thin 
and  indistinct,  and  is  lost  in  the  cribriform 
part  of  the  fascia  lata;"  but  in  this  view  of  its 
termination  the  author  cannot  concur  ;  the  pro- 
longation is  doubtless  connected  to  the  cribri- 
form fascia  (the  superficial  lamina  of  the  iliac 
portion  of  the  fascia  lata)  by  the  vessels,  which 
traverse  both  structures,  but  it  is  notwith- 
standing separable,  without  much  difficulty, 
from  it,  by  means  of  the  proceeding  already 
recommended  for  the  display  of  that  part — 
a  proceeding  equally  applicable  to  that  of  the 
distinct  existence  and  the  connections  of  the 
expansion  in  question  ;  the  superficial  lamina 
being  at  the  same  time,  as  directed  by  Colles, 
divided  from  above  downward,  and  its  parts 
held  to  either  side,  inasmuch  as  a  thin  cellular 

*  Dublin  Dissector,  p.  153. 


FEMORAL  ARTERY. 


241 


oradipo.se  stratum  is  interposed  between  tliem. 
The  last  particular  in  the  disposition  of  the 
prolongation  of  the  fascia  transversalis,  having 
reference  to  the  femoral  artery,  is,  that  it  is 
connected  to  the  back  of  the  femoral  canal 
(the  pubic  portion  of  the  fascia  lata  posterior 
to  the  vessels)  by  two  septa  or  partitions, 
placed,  one  between  the  artery  and  vein,  upon 
the  inside  of  the  former ;  the  other  internal  to 
the  latter,  between  it  and  the  femoral  ring: 
by  those  the  abdominal  aperture  of  the  femoral 
sheath  is  divided  into  three  compartments : 
an  external  one  occupied  by  the  artery,  a  mid- 
dle one  by  the  vein,  and  an  internal  by  the 
lymphatics,  and  at  times  by  a  gland.  The 
two  former  are  so  protected  that  the  occurrence 
of  hernia  through  them  is  rare ;  in  the  case  of 
the  first  probably  impossible;  but  the  internal, 
whether  from  weakness  or  deficiency  of  pro- 
tecting provisions,  allows  its  protrusion,  and 
hence  the  relation  of  the  femoral  vessels,  and 
more  particularly  of  the  artery  to  the  neck  of 
the  sac  of  femoral  hernia,  upon  the  outer  side 
of  which  it  is  always  situate,  separated  from  it 
by  the  vein. 

At  the  lower  part  of  the  first  stage  the  artery 
is  crossed  obliquely  by  the  most  internal  of  the 
deep  branches  of  the  crural  nerve,  which  for 
distinction  sake  might  be  called  internal  geni- 
cular :  it  enters  the  femoral  canal  on  the  out- 
side of  the  vessels  above,  at  a  variable  distance 
from  Poupart's  ligament ;  descends  from 
without  inward  upon  the  front  of  the  artery 
within  the  canal ;  and  escapes  from  it  below 
on  the  inside  of  the  vessel  under  cover  of  the 
sartorius.  Situate,  as  the  nerve  is,  within  the 
femoral  canal,  upon  the  front  of  the  artery, 
and  close'y  connected  to  it  by  the  femoral 
sheath,  it  is  very  likely,  unless  care  be  taken 
to  avoid  it,  to  be  included  in  a  ligature  at  the 
same  time  with  the  vessel :  it  will  not,  how- 
ever, be  always  encountered,  inasmuch  as  it 
crosses  the  artery,  and  at  a  point  higher  or 
lower  in  different  subjects. 

At  times  a  second  branch  of  the  crural 
nerve  crosses  the  artery  in  like  manner  as  the 
former  and  lower  down,  but  it  is  not  to  be 
always  observed. 

Posteriorly  in  its  first  stage  the  artery  rests,  first 
upon  the  inner  margin  of  the  psoas  magnus, 
from  which  it  is  separated  by  the  deep  lamina 
of  the  iliac  portion  of  the  fascia  lata:  while 
so  related,  it  is  situate  over  the  anterior  surface  of 
the  os  innominatum,  external  to  the  iliopec- 
tineal  eminence,  having  the  two  structures, 
already  mentioned,  interposed.*     Below  the 

*  In  this  the  author  has  ventured  to  differ  from 
the  account  usually  given  of  the  relation  of  the 
artery  to  the  os  innominatum,  according  to  which 
( Boyer,  Cloquet,)  the  vessel  must  be  understood 
to  be  situate  internal  to  the  point  mentioned,  being 
said  to  lie  upon  the  os  pubis  ;  but  in  his  opinion 
this  is  not  correct.  The  artery  lies  on  the  psoas, 
which  is  not  internal  to  the  eminence,  and  upon 
the  deep  lamina  of  the  iliac  portion  of  the  fascia 
lata  covering  the  muscle,  which  at  its  most  internal 
part  is  inserted  into  the  eminence;  consequently 
the  vessel,  which  lies  on  the  lamina,  must  be  ex- 
ternal to  that  point  of  bone,  and  observation  will 
be  found  to  confirm  this  view. 
VOL.  II. 


os  innominatum  it  is  placed  over  the  head  of 
the  femur,  from  which  it  is  separated  by  the 
same  parts,  and  also  by  the  capsular  ligament 
of  the  articulation,  and  the  synovial  bursa, 
which  exists  between  the  front  of  the  capsule, 
and  the  psoas  and  iliacus  muscles.  There  are 
then  in  this  situation  two  resisting  surfaces 
against  which  compression  of  the  vessel  may 
be  effected;  and  here  also,  as  observed  by 
Harrison,  a  tumour  with  pulsation  may  occur 
in  case  of  effusion  either  into  the  bursa  simply, 
or  into  the  joint,  when  a  communication  exists 
between  the  former  and  the  synovial  membrane 
of  the  latter. 

Having  passed  the  margin  of  the  psoas  and 
the  head  of  the  femur,  the  artery  corresponds 
to  the  tendon  of  the  psoas  and  iliacus,  to  the 
pectinalis,  and  to  a  small  portion  of  the  ad- 
ductor brevis,  which  parts  it  crosses  obliquely 
in  its  descent :  it  is  not,  however,  in  contact 
with  them,  but  is  separated  from  them  by  a 
space  of  some  depth  occupied  by  cellular 
structure  and  vessels.  The  distance  of  the 
artery  from  the  muscles  varies  according  to 
circumstances  :  when  the  thigh  is  extended  or 
rotated  inward,  it  is  increased;  when,  on  the 
other  hand,  it  is  flexed  or  rotated  outward,* 
it  is  diminished  :  in  the  former  case,  the  artery 
is  brought  nearer  to  the  anterior  surface  of  the 
thigh  by  the  extension,  and  by  the  rotation 
the  lesser  trochanter,  which  is  in  the  middle 
and  deepest  part  of  the  space,  is  carried  back- 
ward from  that  surface. 

The  vessels  which  occupy  the  interval  be- 
tween the  artery  and  the  muscles  are  the  pro- 
funda vein,  the  circumflex  veins,  and  the 
femoral  vein  in  part,  they  being  next  to  the 
artery  and  immediately  behind  it ;  posterior  to 
them  are,  at  times,  the  profunda  artery,  and 
at  the  upper  part,  according  to  circumstances, 
one  or  other  of  the  circumflex  arteries,  when 
arising,  as  in  ordinary,  from  it. 

External  to  the  artery  in  its  first  stage  are 
the  psoas  and  iliacus  muscles,  the  sartorius, 
the  rectus,  and  the  upper  extremity  of  the 
vastus  internus  muscles ;  from  all  which  it  is 
separated  by  the  wall  of  the  femoral  canal. 
At  the  entrance  of  the  artery  into  the  thigh, 
and  for  about  an  inch  below  Poupart's  liga- 
ment, the  crural  portion  of  the  genito-crural 
nerve  is  contained  within  the  femoral  canal  in 
immediate  apposition  with  the  vessel  upon  its 
outer  side.  External  to  it  are  situate  also  the 
crural  nerve  above,  and  itssaphena  branch  below. 
Except  in  rare  instances,  the  profunda  artery 
lies  on  the  outer  side  of  the  femoral  during  a 
greater  or  less  extent  of  its  first  stage ;  but  it 
is,  unless  occasionally  near  to  its  origin,  at  the 
same  time  posterior  to  it,  and  is  subject  to 
varieties  in  its  relation  which  will  be  more 
particularly  detailed  in  the  description  of  that 
vessel. 

Internally  the  artery  corresponds,  though  at 
a  distance,  to  the  pectinalis  and  adductor  mus- 
cles. The  femoral  vein  at  the  upper  part  is 
very  nearly  upon  the  same  level ;  the  artery, 
however,  is  somewhat  anterior  to  it,  probably 

*  Harrison. 

B 


FEMORAL  ARTERY. 


from  resting  upon  the  psoas,  while  the  vein 
corresponds  to  the  pubes  between  that  muscle 
and  the  pectinalis:  hence  the  two  vessels  at 
their  entrance  into  the  thigh,  allowance  being 
made  for  the  trifling  difference  which  has  been 
mentioned,  lie  side  by  side,  the  vein  internal 
to  the  artery ;  but  as  the  former  descends  from 
the  pubes,  it  recedes  from  the  surface  more 
than  the  artery,  and  at  the  same  time  inclines 
outward,  and  thus  it  becomes  posterior  to  it 
at  the  lower  part  of  the  stage,  so  as  to  be  con- 
cealed by  the  artery  by  the  time  it  has  reached 
its  termination.  It  is  included  with  the  artery 
in  the  femoral  sheath,  and  is  separated  from  it 
by  the  external  of  the  two  septa,  which  have 
been  described. 

In  its  second  stage  the  relations  of  the  artery 
differ  considerably  from  those  in  its  first.  In 
the  first  place  it  is  covered  throughout  by  the 
sartorius,  the  muscle  crossing  it  obliquely  from 
without  inward,  and  thence  first  overlapping  it 
by  its  inner  edge,  and  gradually  extending  over 
it  until  the  vessel  is  directly  covered  by  it. 
Secondly,  it  is  in  consequence  covered  by  two 
laminae  of  the  fascia  lata  enclosing  the  muscle; 
one  superficial  to  it,  the  other  beneath  it,  form- 
ing the  front  of  the  femoral  canal ;  it  has  then 
two  new  coverings,  the  muscle  and  the  second 
lamina  of  the  fascia.  Thirdly,  the  femoral  vein, 
which  is  very  closely  connected  to  the  artery, 
is  directly  behind  it,  between  it  and  the  adduc- 
tor longus  muscle,  to  which  the  artery  corre- 
sponds posteriorly.  Fourthly,  it  has  no  part 
deserving  of  attention  upon  its  inside ;  and, 
lastly,  the  saphenus  nerve  is  within  the  femoral 
canal,  along  the  outer  side  of  the  artery  and 
anterior  to  it. 

The  inferior  third  of  the  artery  also  presents 
some  peculiarities  of  relation.  The  vessel  is 
still  covered  by  the  sartorius;  but  here  the 
muscle  is  more  to  the  inner,  as  in  the  second 
stage  it  is  more  to  the  outer  side  of  the  vessel, 
not  only  connecting  it  in  front,  but  also  lying 
against  its  inner  side,  and  the  more  so  the 
nearer  we  approach  the  termination  of  the 
stage  ;  so  much  so  indeed,  that  at  its  termina- 
tion, the  artery,  when  injected,  may  be  felt 
beneath  the  outer  margin  of  the  muscle ;  and 
hence  the  difference  between  the  mode  of  pro- 
ceeding with  regard  to  the  sartorius  recom- 
mended generally  to  be  adopted,  when  occasion 
arises  for  seeking  the  artery  in  its  inferior  third, 
and  that  to  be  pursued  when  the  vessel  is  to 
be  exposed  in  its  second  stage ;  it  being  ad- 
vised, in  the  latter  case,  to  displace  the  inner 
edge  of  the  muscle  outward,  and  in  the  former 
the  outer  inward,  in  order  to  reach  the  vessel 
with  the  greatest  ease  and  certainty.  The  ves- 
sel is  also  covered  by  the  same  two  laminae  of 
the  fascia ;  but  the  deep  one  presents  at  this 
part  remarkable  features :  it  increases  in  thick- 
ness and  is  more  aponeurotic  in  proportion  as 
it  descends,  and  hence  it  is  stronger  the  nearer 
we  approach  the  termination  of  the  course  of 
the  artery  ;  but  in  the  inferior  third  its  thick- 
ness is  still  further  augmented  by  numerous 
tendinous  fibres,  which  pass  from  the  tendons 
of  the  adductors  longus  and  magnus  to  that  of 
the  vastus  internus,  add  very  much  to  the 


thickness  of  the  fascia,  and  give  to  it  the  ap- 
pearance of  a  tendiuous  expansion  of  great 
strength,  connecting  the  tendons  of  the  mus- 
cles, which  have  been  mentioned,  and  covering 
the  artery  upon  its  anterior  and  internal  sides- 
It  is  also  to  be  observed  that  this  accession  of 
fibres  from  the  tendons  exists  only  in  the  infe- 
rior third  of  the  artery's  course,  and  not  in  its 
middle  stage,  and  hence  the  covering  of  the 
vessel  beneath  the  sartorius,  or  the  anterior 
wall  of  the  canal,  is  much  thicker  and  stronger 
in  the  former  than  in  the  latter ;  and  hence 
also  one  of  the  difficulties  encountered  in 
getting  at  the  vessel  in  the  third  stage.  The 
artery  in  this  third  stage  is  situate  upon  the 
inside  of  the  shaft  of  the  femur,  crossing  it  ob- 
liquely from  before  backward  :  it  is  not,  how- 
ever, in  contact  with  the  bone,  but  is  separated 
from  it  by  the  vastus  internus  muscle  :  it  is 
enclosed,  as  before  stated,  between  muscles  ; 
the  sartorius  before  and  internal  to  it,  the  ad- 
ductors longus  and  magnus  behind  it,  and  the 
vastus  internus  on  its  outside. 

The  other  relations  of  the  vessel  in  this  stage 
are  to  the  saphena  vein,  the  saphenus  nerve, 
the  femoral  vein,  and  the  superficial  superior 
internal  articular  artery.  The  first  is  situate 
between  the  femoral  artery  and  the  internal 
face  of  the  thigh,  for  the  most  part  along  the 
inner  margin  of  the  sartorius,  but  varying  some- 
what in  this  respect,  lying  at  times  upou  the 
muscle,  from  its  middle  to  its  inner  edge,  and 
at  others  posterior  to  it.  The  saphenus  nerve 
is  placed  at  first,  as  in  the  second  stage,  exter- 
nal and  anterior  to  the  artery,  but  it  crosses  it 
at  its  termination  and  escapes  from  the  canal, 
upon  its  inside,  in  company  with  the  superficial 
articular  artery,  as  the  vessel  is  about  to  pass 
into  the  popliteal  space.  The  femoral  vein  is 
behind  the  artery  and  somewhat  external  to  it : 
the  latter  relation  of  the  vein  is  expressly  de- 
nied by  Velpeau,*  but  after  careful  examina- 
tion the  author  does  not  hesitate  to  affirm  it. 

The  superficial  superior  internal  articular 
artery,  a  branch  of  the  femoral,  is  given  off  by 
the  artery  immediately  before  its  termination  ; 
it  arises  from  the  front  of  the  vessel,  descends 
nearly  in  the  course  of  it,  escapes  from  the 
femoral  canal  in  company  with  the  saphenus 
nerve,  and,  holding  generally  the  same  relation 
to  that  nerve  which  the  femoral  itself  does,  may 
hence  be  mistaken  for  that  artery  at  the  inferior 
pait  of  its  course. 

Thus  the  relations  of  the  vessel  are  here  in 
several  particulars  the  reverse  of  those  in  its 
former  stages,  and  the  methods  most  eligible 
for  adoption  in  operation  ought  to  be  varied 
accordingly.  Operation  in  its  last  stage  is 
seldom  required,  but  it  may  be  necessary,  as 
in  wounds  of  the  artery  at  that  part,  in  which 
case  the  mode  of  proceeding  with  regard  to  the 
sartorius  and  to  the  artery  should  be  the  reverse 
of  that  recommended  for  the  upper  stage,  the 
muscle  being  to  be  displaced  inward  in  order 
to  expose  the  artery,  and  the  separation  of  the 
latter  from  the  vein  to  be  effected  in  the  same 
direction. 

'  Anatomie  dts  Regiow,  t.  ii.  p.  485.  «d.  1. 


FEMORAL  ARTERY. 


243 


At  the  termination  of  its  third  stage  the 
artery  passes  into  the  ham  and  there  receives 
the  name  of  popliteal :  it  enters  the  popliteal 
region  through  an  elliptical  aperture  situate  to 
the  inside  of  the  femur  at  the  junction  of  its 
middle  and  inferior  thirds,  and  upon  a  plane 
with  its  posterior  face,  the  longer  diameter  of 
which  corresponds  to  the  course  of  the  artery, 
and  which  is  circumscribed  by  the  lower  mar- 
gin of  the  united  tendons  of  the  adductor 
longus  and  the  adductor  magnus  above,  by  the 
connection  between  the  tendon  of  the  adductor 
magnus  and  that  of  the  vastus  interims  below  ; 
by  the  tendon  of  the  adductor  magnus  inter- 
nally, and  by  that  of  the  vastus  internus  exter- 
nally :  in  passing  through,  the  artery  carries 
with  it  a  prolongation  of  the  femoral  sheath,  by 
which  the  popliteal  vessels  become  invested 
and  connected. 

Varieties. — The  superficial  femoral  artery  sel- 
dom presents  a  variation  from  itsaccustomed  dis- 
position,so  much  so  that  it  may  almost  be  held  to 
be  uniform  in  this  respect :  however  two  forms 
of  deviation  have  been  observed,  rare  in  occur- 
rence, but  of  great  importance  in  a  practical 
point  of  view.    Two  instances  of  the  first  ab- 
normal arrangement  are  recorded,  one  of  which 
occurred  to  Sir  Charles  Bell,  and  has  been  pub- 
lished by  him  in  Anderson's  Quarterly  Journal 
for  the  year  1826:  the  second  is  preserved  in 
the  Museum  of  the  College  of  Surgeons,  and 
has  been  described  in  the  fourth  volume  of  the 
Dublin  Hospital  Reports  by  Dr.  Houston, 
Conservator  to  the  Museum.    In  these  cases 
the  femoral  artery  divided  into  two  vessels  of 
nearly  equal  size,  which  pursued  the  usual 
course  of  the  artery  side  by  side  and  very  close 
together,  not,  however,  in  contact,  but  contained 
in  distinct  compartments  of  the  sheath  and 
separated  by  a  septum  :  hence  the  existence  of 
the  second  artery  might  in  operation  easily  pass 
unobserved,  it  not  being  brought  into  view  by 
opening  the  sheath  of  the  other.    One  was 
also  larger  than  the  other,  and  situate  internal 
and  on  a  plane  posterior  to  it.    In  Bell's  case 
the  discovery  was  the  consequence  of  the  un- 
fortunate event  of  an  operation  for  popliteal 
aneurism  ;  the  operation  was  performed  in  the 
middle  third  of  the  thigh.    The  pulsation  of 
the  aneurism,  which  was  arrested  on  the  appli- 
cation of  the  ligature,  returned  after  an  interval 
of  some  seconds,  and  became  nearly  as  distinct 
as  before  :  it  ceased  again  upon  the  third  day, 
but  the  patient  was  carried  off  on  the  sixth  day 
by  an  erysipelatous  inflammation  of  the  thigh. 
On  examination  after  death,  it  was  ascertained 
that  the  disposition,  which  has  been  described, 
was  present,  and  that  but  one  of  the  two  vessels 
had  been  tied. 

The  second  form  of  deviation  is  a  high 
bifurcation  into  the  posterior  tibial  and  peroneal 
arteries :  of  this  an  instance*  has  been  recorded 
by  Sandifort,  in  which  the  division  took  place 
immediately  below  Poupart's  ligament ;  and 
Portalf  states  that  the  crural  artery  has  been 
seen  to  divide  into  two  large  branches  shortly 

•  Green  on  the  Varieties  in  the  Arterial  System, 
and  Sandifort,  Observ.  Anat.  Pathol,  iv.  97. 
t  Anatomie  Medicale,  t.  iii.  p.  326. 


after  its  escape  from  the  abdomen,  and  then 
there  were  two  popliteal  arteries :  he  further 
states  that  among  individuals,  in  which  the 
brachial  artery  was  bifurcated  higher  than  usual, 
the  crural  artery  was  so  also  in  a  remarkable 
proportion.* 

A  division  of  the  femoral  artery  into  two 
trunks  of  equal  size,  running  parallel  and  so 
near  together,  that  they  might  be  conveniently 
included  in  one  ligature,  is  recorded  by  Gooch 
in  the  Philosophical  Transactions  for  the  year 
1  775,  it  being  the  third  instance  in  amputations 
of  the  thigh,  in  which  he  had  observed  such  a 
lasus  natur<E  in  the  arterial  system  ;  but  it  is 
not  mentioned  whether  they  were  instances  of 
the  first  or  of  the  second  kind  of  variety  :  he 
himself,  whether  from  examination  or  from  in- 
ference, appears  to  have  concluded  that  both 
trunks  were  prolonged  into  the  lower  part  of 
the  limb. 

Those  deviations  have  been  accounted  repe- 
titions of  similar  irregularities  in  the  brachial 
artery,  than  which,  however,  they  are  far  less 
frequent.  It  is  a  matter  to  be  regretted  that 
neither  in  the  case  of  Bell,  nor  in  that  of 
Houston,  has  any  account  been  given  of  the 
disposition  of  the  artery  of  the  upper  extremi- 
ties or  of  the  other  thigh. 

Branches  of  the  femoral  artery.  —  The 
branches  given  off"  by  the  femoral  artery  are 
numerous ;  but  the  trunk  of  the  vessel  being 
itself  intended  for  the  supply  of  the  leg  and 
foot,  the  branches  which  it  gives  to  the  thigh 
are,  with  the  exception  of  one  intended  speci- 
ally for  the  nutrition  of  that  part,  inconsider- 
able in  size.  The  artery  gives  branches  to  the 
integuments  of  the  abdomen,  to  the  glands  and 
other  structures  in  the  groin,  to  the  external 
organs  of  generation,  to  the  muscles  in  the 
vicinity  of  which  it  passes,  to  the  inner  side  of 
the  knee;  and,  lastly,  it  gives  the  large  branch, 
adverted  to,  for  the  supply  of  the  thigh,  and  by 
which  those  inosculations  with  other  arteries 
are  formed,  by  means  of  which  chiefly  an  in- 
terruption in  the  course  of  the  main  vessel  is 
compensated.  Those  which  have  received 
names  are  five,  viz.  1.  the  superficial  epigas- 
tric ;  2.  the  superficial  or  external  pudic  ;  3. 
the  superficial  anterior  iliac ;  4.  the  profunda; 
and  5.  the  superficial  superior  internal  articular 
arteries. 

Of  those  the  first  four  arise  from  the  artery 
within  its  first  stage  ;  the  epigastric,  iliac,  and 
pudic  being  given  off  immediately  or  at  a  very 
short  distance  below  Poupart's  ligament ;  and 
the  profunda  at  a  greater  although  a  variable 
distance  from  that  part. 

1.  The  superficial  epigastric  artery  (artire 
sous-cutante  abdorninale,  Cloquet ;  inguinale, 
Chaussier;)  ordinarily  arises  from  the  front  of 
the  femoral,  immediately  below  Poupart's  liga- 
ment. Sometimes  it  is  given  off  from  a  branch 
common  to  it  and  either  one  or  both  the  ex- 
ternal pudics ;  or  it  may  proceed  from  the  pro- 
funda.-f  It  first  comes  forward  through  the 
fascia  lata,  and  then  ascends  over  Poupart's 

•  Ibid.  p.  239. 
t  Boyer, 

m  2 


244 


FEMORAL  ARTERY. 


ligament  upon  the  inferior  part  of  the  abdomen, 
superficial  to  the  aponeurosis  of  the  external 
oblique  muscle,  and  enclosed  in  the  subcuta- 
neous cellular  stratum.  Its  course  is  irregular, 
at  times  nearly  parallel*  to  that  of  the  deep 
epigastric  within  the  abdominal  wall ;  at  others 
ascending  directly  upon  the  abdomen ;  in  ge- 
neral it  pursues  the  latter  course.  It  is  consi- 
derably smaller  than  the  deep  epigastric  artery, 
and  is  concerned  altogether  in  the  supply  of 
superficial  parts,  and  in  establishing  commu- 
nications with  other  vessels.  Its  first  branches 
are  distributed  to  the  inguinal  glands  and  co- 
verings: during  its  ascent  upon  the  abdomen 
it  gives  to  either  side  branches  which  supply 
the  superficial  structures,  and  inosculate  through 
the  ventral  foramina  with  branches  of  the  inter- 
nal epigastric  from  within  ;  and  it  terminates 
by  communicating  with  the  same  and  with 
those  of  the  internal  mammary,  and  of  the 
inferior  intercostals.  It  is,  unless  in  case  of 
disease,  a  small  vessel,  and  of  consequence 
only  from  being  exposed  to  be  divided  in  cer- 
tain operations,  viz.  that  for  inguinal  hernia, 
or  that  for  tying  the  external  iliac  artery. 

2.  The  superficial  or  external  pudic  arteries 
(scrotules  ou  vulvaires,  Chauss.)  are  generally 
two,  distinguished  into  superficialf  and  deep, 
or  superior  X  and  inferior:  of  those  distinc- 
tions the  latter  seems  preferable,  inasmuch  as 
they  are  both  equally  superficial  in  their  dis- 
tribution, and  the  difference  between  them  in 
this  particular  amounts  to  no  more  than  that 
the  second  continues  longer  beneath  the  fascia 
lata  than  the  first.  They  arise  in  general  either 
directly  from  the  femoral,  or  from  a  trunk  com- 
mon to  them  with  the  superficial  epigastric, 
with  which  {hey  are  of  nearly  equal  size. 

The  superior  is  given  oft'  immediately  below 
Poupart's  ligament ;  comes  through  the  fascia 
lata,  and  at  the  same  time  gives  branches  to  the 
inguinal  glands ;  runs,  superficial  to  the  fascia, 
inward  and  also  upward  toward  the  pubes; 
and  either  divides  into  two,  one  of  which  as- 
cends above,  the  other,  the  more  considerable, 
continues  below  that  part ;  or,  as  it  proceeds, 
it  gives  off  small  branches  which  ascend  above 
the  pubis,  and  supply  the  superficial  struc- 
tures upon  the  inferior  middle  part  of  the  ab- 
dominal wall;  while  it  is  itself  continued  to  the 
scrotum  and  side  of  the  penis,  the  coverings 
of  which  it  supplies;  or  into  the  labium  in  the 
female.  Its  branches  communicate  with  those, 
which  the  external  organs  of  generation  receive 
also  from  the  internal  pudic  artery,  and  with 
branches  of  the  epigastric  arteries.  This  branch 
is  usually  divided  in  the  operations  for  either 
inguinal  or  femoral  hernia. 

The  inferior  external  pudic  artery  arises  from 
the  femoral  at  a  greater  distance  from  Poupart's 
ligament  than  the  former:  at  times  it  is  given 
oft'  by  the  profunda  §  artery,  or  from  the  in- 
ternal circumflex,||orfrom  the  superior  branch  \% 
at  others  it  is  absent.**1  It  is  situate  beneath  the 

*  Harrison.       +  Cloquet.       J  Harrison. 
Boyer,  Cloquet,  Tieilemann. 
Harrison. 

Ibid.  »•  Ibid. 


fascia  lata  through  a  greater  extent  of  its  course 
than  the  superior;  runs  inward  across  the  pec- 
tinalis  muscle,  covered  by  the  fascia;  passes 
then  through  the  fascia,  and  pains  the  scrotum 
or  the  labium  and  the  perineum,  in  which  it  is 
distributed,  communicating  with  the  inferior 
branch  of  the  former  and  with  the  perineal 
artery.  Its  course  is  at  times  so  far  from  Pou- 
part's ligament  that  it  crosses  behind  the  sa- 
phena  vein. 

Occasionally  a  third*  external  pudic  artery 
is  present,  arising  either  from  the  femoral  itself, 
the  profunda,  or  the  internal  circumflex  artery. 

3.  The  superficial  anterior  iliac  artery  (ar- 
teria  circumjlexa  iiii  superficial  is,  Harrison ; 
external  cutaneous,  Scarpa ;  artire  musculuire 
superficielle,  Cloquet ;)  arises  from  the  outer 
side  of  the  femoral  artery,  or  at  times  from  the 
profunda  :f  it  runs  outward  in  front  of  the 
crural  nerve,  and  after  a  short  course  divides 
into  three  branches.  Its  first  comes  from  within 
the  fascia  lata  and  is  distributed  to  the  superfi- 
cial inguinal  glands  :  its  second  branch  also 
comes  through  the  fascia,  runs  round  the  ante- 
rior and  outer  side  of  the  thigh,  below  the 
spinous  process  of  the  ilium,  and  is  distri- 
buted superficially :  and  its  third  runs  outward 
and  upward,  beneath  the  fascia  lata,  toward 
the  superior  anterior  spinous  process  of  the 
ilium  ;  supplies  the  sartorius  and  tensor  vagina 
muscles  at  their  origin,  and  also  gives  branches 
to  the  iliacus  interims.  This  artery  communi- 
cates with  branches  of  the  gluteal,  the  deep 
anterior  iliac,  and  the  external  circumflex 
arteries. 

4.  The  profunda  artery  (arteria  profunda 
femoris;  intermusculaire,  Chauss.)  is  the  vessel 
by  which  the  muscles  and  other  structures  of 
the  thigh  are  for  the  greater  part  supplied, 
whence  it  may  be  regarded  as  in  strictness  the 
femoral  artery,  the  trunk  of  the  femoral,  in  its 
general  acceptation,  being  distributed  to  the 
leg  and  foot :  it  is  also  the  channel  through 
which  the  communications  between  the  femoral 
artery  and  the  main  arteries  of  the  trunk  on  the 
one  hand,  and  of  the  lower  part  of  the  limb 
on  the  other,  are  established,  and  by  which,  in 
case  of  interruption  of  the  first  vessel,  either 
below  or  above  the  origin  of  the  profunda,  the 
circulation  is  to  be  restored  :  it  is  therefore  an 
artery  of  great  importance,  and  also  of  great 
size,  being  nearly  equal  to,  though  for  the  most 
part  somewhat  smaller  than,  the  femoral  itself, 
while  in  manycases  it  is  fully  equal  to  it.  Hence, 
probably,  it  has  received  the  name  profunda 

femoris,  deep  femoral  artery;  and  by  many  the 
femoral  artery  is  distinguished  into  the  common 

femoral  and  the  superficial  and  deep  femoruls ; 
the  first  extending  from  the  entrance  of  the 
vessel  into  the  thigh  to  the  origin  of  the  pro- 
funda ;  the  second  being  the  vessel  from  the 
point  last  mentioned  to  that  at  which  it  becomes 
popliteal ;  and  the  third  the  artery  which  is  at 
present  under  consideration. 

The  profunda  artery  for  the  most  part  arises 
from  the  posterior  and  outer  side  of  the  femoral 

*  Scarpa,  Boyer. 
t  Cloquet,  Scarpa- 


FEMORAL  ARTERY. 


245 


at  a  distance,  varying  from  one  to  two  incites, 
below  Poupart's  ligament :  it  descends  thence 
backward  into  the  inguinal  region,  posterior 
to  the  femoral  artery,  and  corresponding  to 
the  muscles  situate  behind  them  in  the  same 
order  as  the  femoral  itself  until  it  reaches  the 
adductor  longus  :  it  then  passes  behind  that 
muscle  and  continues  its  descent  between  it 
and  the  adductor  magnus,  until  after  it  has 
given  oft'  its  last  perforating  branch,  when  it 
also  perforates  the  magnus  at  the  lower  part  of 
the  middle  third  of  the  thigh,  and  finally  is 
distributed  to  the  short  head  of  the  biceps  and 
the  vastus  externus,  gives  to  the  femur  its  in- 
ferior nutritious  artery,  and  anastomoses  with 
the  descending  branches  of  the  external  cir- 
cumflex artery,  and  with  branches  of  the  pop- 
liteal. During  its  descent  the  profunda  recedes 
from  the  surface  more  than  the  femoral  artery, 
so  that  it  lies  nearer  to  the  bottom  of  the  in- 
guinal space,  and  when  placed  directly  behind 
it,  is  separated  from  that  vessel  by  an  interval, 
which  is  occupied  by  the  femoral,  the  pro- 
funda, and  the  circumflex  veins.  It  is  accom- 
panied by  a  corresponding  single  vein  of  con- 
siderable size,  the  profunda  vein,  which  in  the 
upper  part  of  the  thigh  is  situate  before  the 
artery,  intervening,  as  has  been  mentioned, 
between  it  and  the  femoral  artery.  It  is  con- 
tained at  first  within  the  same  sheath  with  the 
femoral ;  but  it  is  presently  received  into  a 
proper  sheath,  an  offset  from  the  back  of  that 
which  encloses  the  other  vessel.  It  has  not  an 
immediate  relation  to  any  nerve. 

Such  are  the  general  relations  of  the  pro- 
funda artery  ;  but  it  presents  frequent  varieties, 
which  derive  importance  from  the  practical 
connections  of  the  femoral  vessels.  The  par- 
ticulars, in  which  it  is  subject  to  diversity,  are 
the  precise  situation  and  relation  of  its  point 
of  origin,  and  the  relation  of  its  course  to  that 
of  the  femoral  artery. 

The  profunda  arises  generally,  as  has  been 
stated,  from  the  posterior  and  outer  side  of  the 
femoral ;  but  at  times  its  origin  is  directly 
behind  that  vessel,  at  others  directly  from  its 
outer  side,  and  occasionally  again  from  its 
inner  side,  as  may  be  seen  from  fig.  3,  tab. 
xxxiii.  of  Tiedemann.  The  situation  of  its 
origin  also  is  variable,  at  times  being  close  to 
Poupart's  ligament,  at  others  at  some  distance 
from  it.  According  to  Boyer*  it  corresponds 
to  "  the  middle  of  the  space  comprised  be- 
tween the  pubis  and  the  little  trochanter ; 
sometimes  higher,  but  rarely  lower."  Accord- 
ing to  Scarpa,f  the  division  of  the  femoral 
artery  takes  place  "  at  the  distance  of  one 
inch,  or  one  and  a  half,  very  rarely  two  inches, 
below  the  crural  arch  in  a  well-formed  adult, 
of  the  ordinary  stature."  According  to  Har- 
rison,! the  profunda  arises  "  in  general  about 
two  inches  below  Poupart's  ligament,  some- 
times an  inch  or  two  lower  down,  and  some- 
times much  nearer  to  this  ligament."    Of  those 

•  Traite  complct  d'Anatomie,  torn-  iii.  p.  150. 
t  Treatise  on  Aneurism,   Wishart's  translation, 
P.  3. 

t  Op.  eit.  vol.  ii.  p.  144. 


three  accounts  that  of  Scarpa  appears  pre- 
ferable :  the  "  distance  between  the  pubis  and 
the  lesser  trochanter"  is  variable,  and  affords 
no  guide  for  the  living  subject,  and  the  author 
has  never  witnessed  the  origin  of  the  vessel 
by  any  means  so  far  from  Poupart's  ligament 
as  the  statement  of  Harrison  would  imply: 
a  distance  of  four  inches,  which  may  be  un- 
derstood from  it  sometimes  to  occur,  would 
bring  the  origin  down  to  the  point  at  which  the 
sartorius  generally  commences  to  overlap  the 
femoral  artery,  and  this  is  manifestly  alto- 
gether too  low ;  while  on  the  other  hand 
Scarpa*  states  expressly  that  it  is  never  below 
the  maximum  point  which  he  has  laid  down, 
viz.  two  inches  from  the  ligament,  and  Hodg- 
sonf  asserts  that  "  it  very  rarely  arises  so  lew 
as  two  inches."  The  maximum  distance  im- 
plied in  the  description  of  Harrison  is  that 
which  has  been  laid  down  by  Bell  as  the  me- 
dium point  of  origin,  on  which  BurnsJ  re- 
marks, "  I  infer  that  Mr.  Bell  has  described 
this  artery  from  dried  preparations,  in  which, 
from  the  retraction  of  Poupart's  ligament,  the 
origin  of  the  profunda  seems  to  take  place 
lower  than  on  the  recent  subject."  The  only 
objection  which  can  be  made  to  the  view  of 
Scarpa,  is  that  the  vessel  not  unfrequently 
arises  nearer  to  the  ligament  than  one  inch 
from  it,  its  origin  being  at  times  abso- 
lutely at  it,  and  having  been  in  some  few 
instances  observed  even  above  the  ligament, 
before  the  femoral  had  escaped  from  the  ab- 
domen, or  more  properly  from  the  external 
iliac  artery :  of  this  extraordinarily  high  origin 
four  instances  have  been  recorded  by  Burns,§ 
and  Tiedemann  ||  has  met  with  it  in  a  female, 
upon  both  sides.  Tiedemann^  has  also  in- 
ferred from  his  researches  that  the  profunda 
arises  nearer  than  usual  to  Poupart's  ligament 
more  frequently  in  females  and  in  subjects  of 
small  stature  than  in  others. 

The  relation  of  the  course  of  the  profunda 
to  that  of  the  femoral  is  the  next  point  of 
variety. 

The  main  course  of  the  former  is  external  to 
that  of  the  latter;  in  arriving  at  its  destination, 
however,  it  does  not  at  all  times  pursue  an 
uniform  course,  but  presents  diversities  in  this 
re>pect,  which  affect  very  much  its  relation  to 
the  femoral  artery.  Its  general  direction  is 
downward,  backward,  and  outward  ;  still  more 
outward  than  the  femoral :  it  is  seldom  how- 
ever direct,  but  describes  one  or  more  inflec- 
tions, by  which  its  course  is  made  at  times  to 
cross  once  or  oftener  that  of  the  other  vessel ; 
and  hence  the  diversities  in  its  relation  to  the 
femoral  which  have  been  adverted  to.  When 
the  course  of  the  vessel  is  direct  or  little  tor- 
tuous, the  profunda  is  situate  throughout, 
external  to  the  femoral,  and  this  relation  would 
appear  to  prevail  at  least  as  frequently  as  any 

•  Op.  cit.  p.  328. 

t  Treatise  on  Diseases  of  Arteries  and  Veins, 
p.  434. 

X  On  Diseases  of  the  Heart,  &c.  p.  319,  20. 
i  Ibid. 

[I  JExplicalio  Tabulanim  Arteriaruin,  p.  323. 
f  Ibid. 


246 


FEMORAL  ARTERY. 


other,  or  to  be  the  most  prevalent,  for  such  is 
the  view  of  the  course  of  the  artery  given  by 
Haller,*  in  two  of  three  views  in  which  the 
relative  course  of  the  two  vessels  is  repre- 
sented, and  by  Tiedemannf  in  two  of  four 
views.  But  at  other  times,  when  the  artery  is 
more  tortuous,  after  descending  for  a  little 
way  external  to  the  femoral,  it  makes  a  turn, 
and  passes  inward  behind  it,  and  thus  fre- 
quently gains  the  inner  side  of  that  vessel 
before  it  reaches  the  adductor  longus,  after 
which  it  again  inclines  outward  toward  its 
destination.  Such  is  the  view  given  of  its 
course  by  Scarpa,^  with  which  the  description 
of  Harrison  coincides :  it  is  similarly  repre- 
sented by  Tiedemann  in  fig.  4,  tab.  xxxiii., 
and  also  by  Haller  §  in  one  instance;  but  the 
author  is  disposed  to  regard  this  as  a  less 
common  disposition,  as  well  from  the  fre- 
quency with  which  he  has  observed  the  former 
one  to  occur,  as  from  the  weight  of  the  autho- 
rities which  have  been  adduced  in  favour  of 
that  opinion.  In  other  but  rare  instances  the 
profunda,  arising  from  the  inside  of  the  femo- 
ral, inclines  at  first  inward  and  becomes  in- 
ternal to  it,  and  then  bending  outward  crosses 
behind  the  femoral  to  its  outer  side:  of  this 
arrangement  an  instance  is  furnished  by  Tiede- 
mann in  fig.  3,  tab.  xxxiii.  And  in  others 
the  artery  does  not  in  the  first  instance  incline 
sensibly  to  either  side;  but  arising  from  the 
back  of  the  femoral  it  descends  behind  that 
vessel,  and  does  not  gain  its  outer  side  until 
it  has  reached  the  lower  part  of  the  inguinal 
region. 

When  the  profunda  artery  arises  very  near 
to  or  above  Poupart's  ligament,  and  from  the 
outer  side  of  the  femoral,  is  large  and  pursues 
its  ordinary  course,  two  arteries  of  equal  or 
nearly  equal  size  may  be  found,  at  the  upper 
part  of  the  inguinal  region,  side  by  side,  and 
upon  the  same  level,  and  thence  liable  to  be 
taken,  either  of  them,  for  the  femoral  artery. 
When  such  an  arrangement  occurs,  the  ex- 
ternal||  of  the  two  vessels  will  almost  certainly 
be  found  to  be  the  profunda,  for  if  that  artery 
have  once  passed  inward  behind  the  femoral, 
it  cannot  afterward  gain  the  same  level  with  it, 
so  as  to  be  situate  at  the  same  time  internal  to 
and  on  the  same  plane  with  it :  further,  as  the 
profunda  descends,  it  recedes  from  the  an- 
terior surface  more  than  the  femoral,  in  order 
to  pass  behind  the  adductor  longus,  and  thus 
it  gains  at  the  lower  part  of  the  region  a  deeper 
situation  than  the  other.  But  inasmuch  as  the 
profunda  occasionally  arises  from  the  inside  of 
the  femoral  artery,  it  may  be  possible  for  it, 
in  case  of  high  origin,  to  be  the  inner  of  the 
two  vessels  adverted  to.  Such  a  circumstance, 
however,  if  it  ever  occur,  must  be  extremely 
rare,  but  in  order  to  guard  against  it,  the  pre- 

*  Icones  Anatomies. 

t  Tabulas  Arteriarum.  Tab.  xxxi.  and  fig.  2. 
tab.  xxxiii. 

%  Reflexions  et  Observations  Anatomico-chirur- 
gicales  sur  l'Aneurisme,  tab.  lire. 
$  Op.  cit. 

||  Harrison,  op.  cit.  vol.  ii.  p.  J65.  Hargrave, 
System  of  Operative  Surgery. 


caution  recommended  of  alternately  compres- 
sing the  vessels  and  ascertaining  the  effect 
previous  to  the  application  of  a  ligature,  should 
never  be  neglected. 

Branches  of  the  profunda  artery . — The  pro- 
funda gives  off  a  considerable  number  of 
branches,  some  of  which  being  distributed  to 
the  muscles,  by  which  the  artery  passes,  and 
not  being  remarkable  either  for  their  size  or 
their  communications,  have  not  received  par- 
ticular names.  Those  which  are  most  de- 
serving of  attention,  whether  for  their  size, 
the  extent  and  peculiarity  of  their  course,  or 
the  anastomoses  which  they  form  with  other 
arteries,  are  five  or  six  in  number,  viz.  two 
circumflex  arteries,  and  three  or  at  times  four 
perforating  arteries.  The  circumflex  arteries 
are  so  named  because  they  wind  round  the 
upper  extremity  of  the  femur,  and  form  an 
arterial  circle  around  it :  they  are  distinguished 
by  the  epithets  external  and  internal,  being 
destined,  one  to  the  outer,  the  other  to  the 
inner  side  of  the  limb :  they  are  vessels  of 
considerable  size  and  importance  because  both 
of  the  extent  of  parts  which  they  supply,  and 
of  the  communications  which  are  established 
through  them  between  the  femoral,  the  arteries 
of  the  pelvis,  and  those  of  the  lower  parts  of 
the  limb. 

tt  The  external  circumflex  artery  at  times 
is  the  first  branch  of  the  profunda ;  at  others 
it  is  preceded  by  the  internal  circumflex  :  it  is 
given  off  from  the  profunda  while  it  lies  on 
the  outside  of  the  femoral  at  a  variable  dis- 
tance from  Poupart's  ligament,  and  arises  from 
the  outer  side  of  the  artery  :  occasionally  it  is 
given  off  by  the  femoral  itself;  it  runs  directly 
outward,  or  outward  and  downward,  in  front 
of  the  psoas  and  iliacus  muscles;  beneath  the 
sartorius  and  rectus,  and  either  between  or 
behind  the  divisions  of  the  crural  nerve ;  and 
divides  after  a  short  course  into  three  branches, 
viz.  an  ascending,  a  descending,  and  a  circum- 
flex. 

a.  The  first,  the  ascending  branch,  runs  up- 
ward and  outward  toward  the  superior  anterior 
spinous  process  of  the  ilium,  between  the 
iliacus  internus  and  the  glutreus  medius  mus- 
cles, and  concealed  by  the  tensor  vaginas 
femoris :  as  it  proceeds,  it  gives  branches  to 
those  muscles;  and  having  reached  the  outer 
and  back  part  of  the  spinous  process,  it  ter- 
minates in  an  anastomosis  with  a  branch  of 
the  glutceal,  and  also  with  the  deep  cir- 
cumflex ilii  arteries.  The  anastomosis  with 
the  glutceal  artery  becomes  remarkably  en- 
larged when  the  main  vessel  is  interrupted 
above  the  origin  of  the  profunda,  as  may  be 
seen  from  Sir  A.  Cooper's  case  of  femoral 
aneurism.* 

b.  The  second,  the  descending  branch,  runs 
downward  and  outward  beneath  the  rectus 
muscle,  between  it  and  the  triceps  crural,  and 
divides  after  a  short  course  for  the  most  part  into 
several  branches  of  considerable  size  and  great 
length  for  the  supply  of  those  muscles  and  for 
establishing  communications :  the  branches  are 

*  Guy's  Hospital  Reports,  Jan.  1836,  pi*  1. 


FEMORAL  ARTERY. 


247 


at  times  so  many  as  five  or  six,  and  are  dis- 
tributed one  or  more  to  the  rectus,  entering 
the  muscle  upon  its  deep  surface,  and  pro- 
longed to  a  great  length  within  its  substance  ; 
one  to  the  vastus  internus,  one  to  the  cruraeus, 
and  one  or  two  to  the  vastus  extern  us  :  they 
are  accompanied,  several  of  them,  by  branches 
of  the  crural  nerve,  and  they  run  for  a  con- 
siderable distance,  particularly  the  infe- 
rior branch  to  the  vastus  externus,  between 
the  divisions  of  the  triceps  crural  muscle, 
before  entering  their  substance  :  they  are  pro- 
longed very  low  down,  and  may  be  followed 
some  of  them  to  near  the  knee,  where  they 
anastomose  with  branches  of  the  femoral  in 
the  vastus  internus,  and  with  the  superior 
articular  arteries.  But  the  branches  of  the 
descending  division  of  the  external  circum- 
flex artery  are  by  no  means  uniform  in  number 
or  destination,  more  or  fewer  of  the  arteries 
just  described  being  at  times  branches  of  the 
profunda  itself;  thus,  at  times  that  to  the 
vastus  internus,  that  to  the  cruraeus,  and  that 
to  the  rectus,  arise  from  the  profunda  below 
the  circumflex,  and  in  such  case  the  descend- 
ing branch  of  the  latter  consists  solely  of  the 
branch  or  branches  destined  to  the  vastus  ex- 
ternus muscle. 

c.  The  third,  the  circumflex  branch,  pursues 
at  first  the  course  of  the  original  vessel,  and 
runs  outward  across  the  upper  extremity  of  the 
shaft  of  the  femur  below  the  great  trochanter, 
beneath  the  rectus  and  tensor  vaginae  muscles, 
and  superficial  to  the  cruraeus.  It  gives,  in 
this  situation,  branches  to  the  cruraeus,  the 
iliacus,  the  rectus  and  tensor  muscles.  It 
then  passes  backward  upon  the  outside  of  the 
femur  to  its  posterior  part,  and  thus  surrounds 
the  bone  upon  its  anterior  and  external  sides. 
In  the  latter  part  of  its  course  it  traverses  the 
upper  extremity  of  the  vastus  externus,  and 
gives  off,  1.  branches  upward  and  downward 
into  the  muscle;  2.  a  branch  or  branches  which 
run  between  the  vastus  and  the  bone,  and 
supply  the  periosteum ;  3.  a  branch  to  the 
gluteus  maximus  at  its  insertion,  which,  after 
furnishing  it  branches,  perforates  the  muscle 
and  becomes  superficial.  The  circumflex  divi- 
sion of  the  external  circumflex  anastomoses 
with  the  internal  circumflex,  the  gluteal,  the 
sciatic,  and  the  perforating  arteries.  The  ex- 
ternal circumflex  artery  is  accompanied  by  a 
large  vein,  which  crosses  between  the  femoral 
and  profunda  arteries,  superficial  to  the  latter, 
in  order  to  join  the  femoral  or  the  profunda 
vein. 

2.  The  internal  circumflex  artery  is  a  larger 
vessel  than  the  external :  it  is  given  off  by  the 
profunda  usually  after  the  external,  and  arises 
from  the  inner  side  of  the  artery,  but  at  times 
it  arises  before  the  external.  According  to 
Harrison  it  "  very  frequently  proceeds  from  the 
femoral  artery,  prior  to  the  origin  of  the  pro- 
funda ;"  it  has  been  found  by  Burns*  arising 
from  the  external  iliac  artery,  and  also  from  the 
femoral  artery  a  little  below  the  crural  arch. 
In  the  former  case  "  it  ran  along  the  front  of 


the  lymphatic  sheath  f  and  in  the  second  "  it 
traversed  the  front  of  the  common  sheath  of 
the  great  vein  and  also  of  the  lymphatics ;"  and 
in  either  case,  as  observed  by  Burns,  it  must 
be  exposed  to  great  danger  in  operation  for 
femoral  hernia.  According  to  Green,*  both 
circumflex  arteries  sometimes  are  furnished 
from  a  common  trunk.  It  runs  inward,  back- 
ward, and  downward  toward  the  lesser  tro- 
chanter into  the  deepest  part  of  the  inguinal 
region,  and  escapes  from  that  spare  posteriorly 
between  the  tendon  of  the  psoas  and  the  pecti- 
nalis  muscles  ;  continues  its  course  backward, 
on  the  inside  of  the  neck  of  the  femur  and  the 
capsular  ligament,  below  the  obturator  exter- 
nus, behind  the  pectinalis,  and  anterior  to  the 
adductor  magnus  and  the  quadratus  muscles, 
until  it  has  got  behind  the  neck  of  the  bone; 
and  lastly,  it  passes  through  the  internal,  which 
separates  the  inferior  margin  of  the  quadratus 
femoris  from  the  upper  margin  of  the  adductor 
magnus,  and  thus  gains  the  posterior  region  of 
the  thigh,  where  it  terminates  as  will  be  de- 
scribed. 

The  internal  circumflex  artery  is  the  vessel 
which  gains  the  deepest  situation  in  the  groin : 
it  is  internal  and  posterior  to  the  profunda,  and 
when  it  arises  from  that  artery,  while  external 
to  the  femoral,  it  crosses  the  latter  vessel  poste- 
riorly in  its  course.  While  within  the  inguinal 
region  the  internal  circumflex  artery  gives  off 
first  a  branch  to  the  iliacus  and  psoas  muscles: 
then  a  considerable  branch,  denominated  by 
Tiedemann  superficial  circumflex  branch,  which 
contributes  to  supply  the  pectinalis,  the  adduc- 
tor longus,  and  the  adductor  brevis :  it  runs 
upward  and  inward  upon  the  pectinalis,  at  the 
same  time  giving  branches  to  it  and  to  the  ad- 
ductor longus,  until  it  reaches  the  interval  be- 
tween these  muscles  :  it  then  divides  into  two, 
of  which  one  ascends  in  the  course  of  the 
original  branch,  between  the  muscles  men- 
tioned, toward  the  origin  of  the  adductor  longus, 
supplying  the  two  muscles,  and  ultimately 
anastomosing  with  branches  of  the  obturator 
artery  :  small  branches  of  it  traverse  the  adduc- 
tor, and  become  cutaneous  upon  the  upper  and 
inner  part  of  the  thigh.  The  second  branch 
passes  downward  and  backward,  also  between 
the  pectinalis  and  the  adductor  longus,  gains 
the  anterior  surface  of  the  adductor  brevis,  and 
there  meets  the  obturator  vessels  and  nerves: 
it  divides  into  several  branches,  of  which  some 
are  distributed  to  the  last  muscle,  some  anas- 
tomose with  the  obturator  artery,  and  others 
with  the  upper  perforating  artery. 

Behind  the  pectinalis  the  internal  circumflex 
artery  gives  several  branches.  Downward  it 
gives  a  considerable  one  to  the  adductor  mag- 
nus, which  descends  into  that  muscle,  supplies 
it  and  anastomoses  with  the  perforating  arteries. 
Upward  and  forward  it  gives  to  -the  adductor 
brevis  and  the  obturator  externus  branches 
which  communicate  freely  with  the  obturator 
artery  after  its  escape  from  the  pelvis.  Out- 
ward it  gives  the  articular  artery  of  the  hip  a 
branch,  small,  but  remarkable  for  its  course  and 


*  Op.  cit.  p.  319. 


*  Op.  cit.  p.  31. 


248 


FEMORAL  ARTERY. 


destination ;  it  enters  the  articulation  beneath 
the  transverse  ligament,  through  the  notch  at 
the  internal  and  inferior  part  of  the  margin  of 
the  acetabulum,  over  which  the  ligament  is 
thrown ;  supplies  the  adipose  structure  which 
occupies  the  bottom  of  the  socket,  and  is  con- 
ducted by  the  ligamentum  teres  to  the  head  of 
the  femur,  in  which  it  is  ultimately  distributed. 
That  part  of  the  artery  which  reaches  the  head 
of  the  femur  is  of  very  inconsiderable  size,  and 
is  the  source  upon  which  the  nutrition  of  that 
part  depends  in  fracture  of  the  neck  of  the  bone 
within  the  capsule.  Lastly,  upward  and  back- 
ward the  artery  sends  off  a  considerable  and 
regular  branch  which  is  usually  described  as 
one  of  its  terminating  branches,  but  which,  in 
the  opinion  of  the  author,  may  with  more  pro- 
priety be  considered  as  belonging  to  its  middle 
stage.  It  passes  upward  and  outward  between 
the  obturator  externus  and  the  quadratus  mus- 
cles to  the  trochanteric  fossa,  where  it  is  dis- 
tributed to  the  muscles  inserted  behind  the 
trochanter,  viz.  to  those  which  have  been  just 
mentioned ;  to  the  obturator  internus,  the 
gemelli,  the  pyriformis,  the  glutei  medius  and 
minimus,  and  to  the  back  of  the  ilio-femoral 
articulation,  and  where  it  inosculates  with  the 
gluteal,  sciatic,  and  external  circumflex  arte- 
ries. It  may  be  appropriately  called  the  poste- 
rior trochanteric*  branch. 

After  its  passage  between  the  quadratus  and 
the  adductor  magnus,  the  circumflex  artery 
divides,  in  the  posterior  region  of  the  thigh, 
into  an  ascending  and  a  descending  branch. 
The  former  passes  upward  to  the  origin  of  the 
biceps,  semi  -  membranosus  and  tendinosus 
muscles,  and  to  the  gluteus  maximus ;  the 
latter  downward  to  the  former  muscles,  to  the 
adductor  magnus,  and  to  the  sciatic  nerve. 
They  communicate  with  the  sciatic,  the  exter- 
nal circumflex,  and  superior  perforating  arte- 
ries. 

The  perforating  arteries  are  three  or  four  in 
number.  They  are  given  off  backward  by  the 
profunda,  below  the  origin  of  the  circumflex 
arteries,  and  are  denominated  numerically  first, 
second,  third,  &c.  They  all  pass  from  the  an- 
terior to  the  posterior  region  of  the  thigh  by 
perforating  the  adductor  magnus,  and  at  times 
also  the  adductor  brevis,  whence  their  name ; 
they  divide  for  the  most  part  into  ascending 
and  descending  branches,  and  are  consumed 
partly  in  the  supply  of  that  region,  and  partly 
in  establishing  a  chain  of  communications  be- 
tween the  arteries  of  the  trunk  and  the  main 
artery  at  the  upper  and  the  lower  parts  of  the 
thigh. 

3.  The  first  perforating  artery  arises  from  the 
profunda  immediately  below  the  lesser  trochan- 
ter, nearly  opposite  the  lower  margin  of  the 
pectinalis  :  it  passes  backward,  descending  a 
little  below  the  lower  margin  of  the  pectinalis, 
either  between  it  and  the  upper  one  of  the  ad- 
ductor brevis,  or  through  an  aperture  in  the 
latter  muscle :  it  next  perforates  the  adductor 
magnus  close  to  the  linea  aspera,  and  so  gains 
the  posterior  region  of  the  thigh,  where  it 

*  Scarpa,  op.  cit. 


divides  into  two  or  three  large  branches,  of 
which  one  ascends  and  is  distributed  to  the 
gluteus  maximus,  communicating  with  the 
gluteal,  sciatic,  and  circumflex  arteries;  ano- 
ther descends,  supplies  the  long  head  of  the 
biceps,  the  semi-membranosus  and  semi-tendi- 
nosus,  and  communicates  with  the  inferior  per- 
forating arteries  ;  and  the  third  runs  downward 
and  outward  into  the  vastus  externus,  through 
which  it  descends,  communicating  at  the  same 
time  with  the  external  circumflex  artery.  The 
artery  also  gives  branches  to  the  sciatic  nerve, 
and,  during  its  passage  from  the  front  to  the 
back  of  the  thigh,  to  the  pectinalis  and  the  ad- 
ductors. According  to  Hairison,  f  this  artery 
is  sometimes  a  branch  of  the  internal  circum- 
flex ;  its  course  is  nearly  parallel  to  that  vessel, 
and  is  separated  from  it  by  the  tendon  of  the 
pectinaeus  muscle,  the  first  perforating  artery 
passing  below  that  teudon,  while  the  circumflex 
artery  runs  superior  to  it." 

4.  The  second  perforating  artery  is  generally 
the  largest  of  those  vessels :  it  arises  a  short 
distance  below  the  first,  and  passes  through 
both  the  adductors  brevis  and  magnus  ;  it  then 
divides,  like  the  former, into  ascending  and  de- 
scending branches  :  the  former  are  distributed 
to  the  gluteus  maximus,  the  vastus  externus, 
and  the  tensor  vaginae,  likewise  anastomosing 
with  the  first  perforating,  the  gluteal,  sciatic, 
and  circumflex  arteries :  the  latter  are  distri- 
buted to  the  biceps,  semi-membranosus,  and 
semi-tendinosus,  the  vastus  externus,  and  the 
integuments  of  the  back  of  the  thigh,  and  in- 
osculate with  the  inferior  perforating  and  with 
branches  of  the  popliteal  artery.  The  artery 
also  gives  branches  to  the  adductor  muscles 
and  to  the  sciatic  nerve  and  the  nutritious  artery 
of  the  femur,  which  enters  a  canal  to  be  ob- 
served in  the  linea  aspera,  at  the  junction  of 
the  first  and  second  thirds  of  the  thigh,  leading 
obliquely  upward  into  the  bone.  The  second 
perforating  artery  at  times  does  not  pass 
through  the  adductor  brevis,  but  when  the  first 
does  so,  it  generally  runs  inferior  to  it,  perfora- 
ting the  adductor  magnus  only. 

5.  The  third  perforating  artery  is  smaller 
than  either  of  the  former,  and  arises  lower 
down  ;  according  to  Harrison,  at  the  upper 
edge  of  the  adductor  longus  muscles,  it  passes 
through  the  adductor  magnus,  and  divides  in 
the  same  manner  as  the  others  :  its  branches 
are  also  similarly  distributed,  and  anastomose 
with  the  second  perforating  artery  from  above, 
and  with  branches  of  the  popliteal  from  below. 

When  a  fourth  perforating  artery  exists,  if. 
pursues  a  similar  course  and  is  distributed 
similarly  to  the  last.  The  perforating  branches 
of  the  profunda  are  subject  to  much  varietj 
with  regard  to  number,  size,  and  precise  course 
and  distribution  ;  so  much  so  that  they  hardly 
admit  a  definite  description  :  the  preceding  ac- 
count has  been  taken  from  a  comparison  of  the 
most  approved  authorities  with  the  subject,  in 
order,  as  far  as  possible,  to  embrace  their  nu- 
merous irregularities. 

Beside  those  branches,  which  have  been 
enumerated,  to  which  proper  names  have  been 
given,  the  profunda  artery  gives  off  during  its 


FEMORAL  ARTERY. 


249 


course  others  less  regular  and  less  considerable, 
which  are  distributed  to  the  muscles  in  its 
vicinity.  Those  are  a  branch  to  the  pectinalis 
and  adductor  muscles,  and  one  or  more  to  the 
vastus  internus  and  cruraeus  muscles :  it  has 
been  elsewhere  stated  that  the  descending 
branches  of  the  external  circumflex,  destined 
to  the  last-named  muscles,  and  one  of  those  to 
the  vastus  externus,  at  times  also  arise  from  the 
profunda  itself.  After  having  given  off  the  last 
perforating  artery,  the  profunda,  very  much 
reduced  in  size,  continues  its  descent  behind 
the  adductor  longus  muscle,  inclining  at  the 
same  time  outward,  and  external  to  the  femoral 
artery  :  it  passes  through  the  adductor  magnus 
a  little  above  the  passage  of  the  femoral  into 
the  ham,  giving  it  small  branches;  then  tra- 
verses the  origin  of  the  short  head  of  the  biceps, 
giving  it  also  branches  ;  and,  lastly,  enters  into 
the  outer  part  of  the  vastus  externus,  through 
which  it  descends  frequently  to  near  the  knee, 
distributing  branches  to  the  muscle,  and  anasto- 
mosing with  the  descending  branches  of  the 
external  circumflex  and  with  the  external  arti- 
cular artery.  The  termination  of  the  profunda 
is  by  some*  called  the  fourth  perforating 
artery. 

The  profunda  resembles  very  much  in  its 
course  and  termination  the  superior  profunda 
or  musculo-spiral  branch  of  the  brachial  artery, 
to  which  it  may  be  considered  analogous. 

Immediately  before  the  femoral  artery  passes 
into  the  popliteal  space,  it  gives  off  its  fifth  and 
lowest  branch.  This  is  usually  called  the 
anastomotica  magna  artery,  but  there  being  no 
more  reason  to  apply  the  epithet  anastomotic 
to  it  than  to  the  other  brandies  of  the  femora, 
and  the  great  anastomotic  artery  of  the  thigh 
being  in  reality  the  profunda,  the  name  given 
to  it  by  Tiedemann  seems  much  to  be  preferred, 
viz.  superficial  superior  internal  articular. 
It  arises  from  the  front  of  the  femoral  at  the 
inferior  part  of  its  last  stage,  and  immediately 
escapes  from  within  the  femoral  canal,  passing 
through  its  anterior  wall  at  the  same  time  with 
the  saphenus  nerve,  as  the  femoral  itself  is 
about  to  pass  into  the  ham.  Having  come 
through  the  aponeurosis  forming  the  wall  of  the 
canal,  it  descends  for  some  distance  toward  the 
inside  of  the  knee  parallel  to  the  tendon  of  the 
adductor  magnus  and  anterior  to  it  in  company 
with  the  saphenus  nerve,  and  covered  by  the 
sartorius  muscle.  After  a  short  course  it  divides 
into  two  branches.  One  of  these  runs  down- 
ward and  forward,  in  front  of  the  adductor 
magnus,  toward  the  patella ;  enters  the  vastus 
internus  and  traverses  it  in  its  course  ;  divides 
within  it  into  two  branches,  of  which  one  runs 
between  the  muscle  and  the  bone,  and  supplies 
the  periosteum  of  the  femur  and  the  capsule  of 
the  articulation,  anastomosing  at  the  same  time 
with  the  deep  articulars;  the  other  continues 
its  course  through  the  vastus,  supplying  the 
muscle,  until  it  reaches  the  side  of  the  tendon 
of  the  extensors  :  it  then  becomes  superficial  to 
the  tendon,  and  descends  upon  the  front  of  the 
patella,  ramifying  freely  upon  it,  supplies  the 

*  Scarpa,  op.  cit.  p.  17,  18. 


integuments  and  other  superficial  structures  of 
the  articulation  on  its  anterior  part,  and  com- 
municates freely  with  the  other  articular  arte- 
ries. 

The  second  branch,  into  which  the  superfi- 
cial articular  divides,  descends  posterior  to  the 
tendon  of  the  adductor,  in  company  with  the 
saphenus  nerve,  and  covered  by  the  sartorius  : 
as  it  descends,  it  gives  branches  to  the  ham- 
string muscles,  the  semi-membranosusandsemi- 
tendinosus,  and  also  to  the  sartorius  :  when  it 
has  reached  the  inner  side  of  the  knee,  it  divides 
into  two,  of  which  one  passes  forward  beneath 
the  aponeurosis,  upon  the  internal  condyle  of 
the  femur,  divides  into  branches  which  supply 
the  superficial  structures  of  the  joint  upon  its 
inside,  can  be  traced  forward  beneath  the  pa- 
tella, and  form  free  communications  with  the 
other  articular  arteries,  more  particularly  with 
the  inferior  internal  one:  the  second  descends 
to  the  leg,  escapes  from  beneath  the  tendon  of 
the  sartorius,  and  then,  turnin?  forward,  rami- 
fies over  the  internal  surface  of  the  tibia  below 
its  tubercle,  supplies  the  insertions  of  the  mus- 
cles and  the  coverings,  and  communicates  with 
branches  of  the  internal  articular  and  of  the 
tibial  recurrent  arteries.  The  superficial  supe- 
rior internal  articular  artery  is  variable  in  size  : 
at  times  it  is  of  very  considerable  magnitude ; 
at  others  it  is  small,  or  even  absent  altogether, 
its  place  being  supplied  by  a  branch  of  the 
popliteal  artery.  Its  distribution  also  varies 
with  its  size,  the  extent  of  the  former  being 
proportioned  to  the  latter. 

The  course  of  the  artery  diverges  but  little 
from  that  of  the  femoral,  and  the  relation  of  the 
saphenus  nerve  to  it  is  almost  the  same  as  that 
which  the  nerve  holds  to  the  latter  vessel  : 
hence,  when  the  branch  is  large,  it  is  liable  to 
be  mistaken  in  the  operation  of  tying  the  main 
vessel,  particularly  in  case  of  wound  of  the 
artery,  for  the  femoral  itself.  The  description 
of  the  articular  artery  here  given  has  been 
taken  from  the  plate  of  Tiedemann,  in  which 
the  vessel  is  reprpsented  with  its  most  extended 
distribution. 

The  femoral  artery  also  gives  off,  during  its 
descent  through  the  thigh,  beside  the  branches 
which  have  been  described,  several  others  to 
the  muscles  which  are  in  its  vicinity ;  above,  it 
sends  branches  to  the  sartorius,  lliacus,  and 
pectinalis;  and  in  the  middle  of  the  thigh  to 
the  vastus  internus  on  the  one  hand,  and  to  the 
adductor  muscles  on  the  other.  Those  branches 
are  for  the  most  part  inconsiderable  in  size, 
and  have  not  received  names,  but  they  are  de- 
serving of  attention,  inasmuch  as  they  coope- 
rate in  the  collateral  circulation,  more  particu- 
larly the  second  set,  through  which  the  femoral 
artery  is  generally  preserved  pervious,  after 
ligature  below  the  origin  of  the  profunda,  during 
a  greater  or  less  extent  of  the  interval  between 
the  ligature  and  the  popliteal  artery,  by  means 
of  the  anastomoses  between  the  branches  in 
question  and  the  circumflex  arteries. 

The  adequacy  of  the  collateral  circulation  in 
the  thigh  to  the  maintenance  and  nutrition  of 
the  limb  after  the  interruption  of  the  femoral 
artery,  has  been  so  long  established  that  it  is 


250 


FEMORAL  ARTERY. 


at  present  unnecessary  to  insist  upon  it.  But 
the  channels  through  which  the  circulation  of 
the  blood  becomes  in  such  cases  restored,  as 
well  as  the  relations  of  the  new  circulation,  are 
deserving  of  attention. 

The  collateral  connections  of  the  femoral 
artery  are  distinguishable  into  those  between  it 
and  the  arteries  of  the  trunk,  those  between  it 
and  the  popliteal  and  arteries  of  the  leg,  and 
those  between  different  parts  of  its  own  course. 

The  communication  of  the  femoral  artery 
with  the  arteries  of  the  trunk  are  established 
between  it  and  both  the  internal  and  the  external 
iliacs. 

Those  with  the  internal  iliac  are  formed,  1. 
by  means  of  the  inosculations  of  the  branches 
of  the  profunda,  the  circumflex  and  perforating 
arteries  with  the  obturator,  glutceal,  and  sciatic 
arteries,  all  branches  of  the  latter;  2.  by  those 
between  the  internal  and  external  pudics ;  and, 
3.  by  the  communications  of  the  ilio-lumbar 
artery  with  the  deep  anterior  iliac,  by  which  the 
blood  may  be  transferred  to  the  superficial  an- 
terior iliac  or  the  external  circumflex. 

From  the  obturator  artery  the  bl  ood  is  transmit- 
ted through  theascending  branches  of  the  internal 
circumflex  :  this  channel  of  communication  be- 
comes, in  cases  of  interruption  of  the  external 
iliac  artery,  remarkably  free,  the  branches  esta- 
blishing it  being  much  enlarged  and  tortuous  : 
instances  and  representations  of  it  may  be 
found  in  the  Medico-Chirurgical  Transactions, 
vol.  iv.  and  in  Guy's  Hospital  Reports,  IN o.  1, 
Jan.  1836,  from  the  experience  of  Sir  Astley 
Cooper. 

Through  the  glutceal  artery  the  femoral  com- 
municates with  the  internal  iliac  by  the  inoscu- 
lations between  that  vessel,  the  posterior  tro- 
chanteric and  the  ascending  terminal  branches 
of  the  internal  circumflex,  and  by  those  between 
it  and  the  ascending  and  circumflex  branches 
of  the  external  circumflex  artery  :  those  connec- 
tions are  displayed  also  in  the  works  just 
referred  to. 

The  communication  of  the  femoral  with  the 
internal  iliac  through  the  sciatic  artery  is  esta- 
blished by  the  anastomosis  of  that  vessel  with 
the  internal  circumflex  and  the  perforating  arte- 
ries, for  which  also  see  the  same  works. 

The  alteration  in  the  condition  of  the  sciatic 
artery  or  its  branches  caused  by  ligature  of  the 
femoral  or  of  the  external  iliac  artery  presents 
one  of  the  most  remarkable  results  of  that  cir- 
cumstance :  its  branch  to  the  sciatic  nerve  be- 
comes greatly  enlarged,  very  tortuous,  and  so 
much  elongated  as  to  form  at  times  a  commu- 
nication between  the  sciatic  artery  and  the 
posterior  tibial.  The  connections  established 
through  the  pudic  and  ilio-lumbar  arteries  are 
set  forth,  in  the  event  of  a  case  of  ligature  of  the 
external  iliac  artery  published  in  the  Medico- 
Chirurgical  Transactions,  vol.  xx.  by  Mr. 
Norman. 

The  femoral  artery  communicates  with  the 
external  iliac  through  means  of  the  anastomoses 
between  the  anterior  iliac  arteries,  internal  and 
external,  between  the  internal  anterior  iliac  and 
the  external  circumflex  ;  and  also  by  those  be- 
tween the  superficial  and  internal  epigastrics. 


By  the  communications,  which  have  been 
mentioned,  the  transmission  of  blood  through 
the  femoral  artery  may  be  restored,  after  the 
interruption  of  the  external  iliac  artery,  or  of 
the  femoral  above  the  origin  of  the  profunda, 
with  sufficient  freedom  for  the  perfect  nutrition 
of  the  limb ;  of  which  numerous  instances  have 
been  observed  by  different  writers. 

The  upper  and  lower  parts  of  the  femoral 
artery  are  also  connected  by  collateral  channels. 
Those  are  established  by  the  communications 
which  exist  between  the  branches  of  the  pro- 
funda artery  arising  from  the  upper  extremity 
of  the  femoral,  and  branches  of  the  latter  given 
off  during  its  course  or  from  its  lower  extre- 
mity ;  thus  the  blood  may  pass  from  the  femo- 
ral artery  above  into  the  middle  part  of  the 
vessel  through  the  anastomosis  existing  between 
the  descending  branches  of  the  external  circum- 
flex artery,  and  the  branches  given  by  the  femo- 
ral to  the  vastus  internus  muscle  about  the 
middle  of  the  thigh. 

A  similar  communication  exists  upon  the 
internal  side  of  the  femoral  by  means  of  the 
anastomoses  by  which  descending  branches  of 
the  internal  circumflex  are  connected  with  those 
given  by  the  femoral  itself  to  the  adductors. 

The  collateral  connection  of  the  femoral  with 
the  popliteal  artery  is  established  through  two 
channels:  1.  through  the  anastomoses  between 
the  branches  of  the  profunda,  as  well  the  ex- 
ternal circumflex  as  the  perforating  arteries, 
with  the  branches  of  the  popliteal;  whence 
the  femoral  may  be  interrupted  at  any  part 
below  the  origin  of  the  profunda,  and  the 
blood  thus  find  a  ready  passage  from  it  into 
the  popliteal :  2.  through  those  of  the  branches 
given  by  the  femoral  to  the  vastus  internus  and 
the  superficial  superior  internal  articular  with 
the  same. 

To  the  channels  of  communication  which 
have  been  described  are  to  be  added,  as 
pointed  out  by  Scarpa,  those  established,  by 
the  arteries  of  the  periosteum  and  of  the  in- 
ternal structure  of  the  femur,  between  the 
main  arteries  above  and  below.  The  former 
are  well  represented  by  Scarpa,*  and  are  formed 
by  anastomoses  between  branches  of  the  external 
circumflex,  the  profunda,  the  femoral  and  the 
popliteal  distributed  to  the  periosteum. 

Upon  a  review  of  the  anastomotic  con- 
nections of  the  femoral  artery,  its  course  pre- 
sents two  stations  at  which  communications 
are  established,  on  the  one  hand  with  the 
main  artery  above,  and  on  the  other  with  that 
below,  while  in  the  interval  they  are  connected 
the  one  with  the  other.  Those  are,  1.  the  first 
part  of  the  vessel's  course  from  its  commence- 
ment to  below  the  origin  of  the  profunda ; 
and,  2.  its  lower  part  for  so  much  of  it  as 
includes  the  origins  of  the  branches  to  the 
triceps  crural  and  adductor  muscles,  and  the 
superficial  superior  internal  articular. 

Again,  it  appears  that  through  the  first 
station,  not  only  is  the  femoral  connected  with 
the  arteries  of  the  trunk  and  with  the  lower 
part  of  the  vessel,  but  also  it  is  connected 

*  Reflexions  sur  l'Aneurisme,  tab.  ii. 


FEMORAL 

without  the  intermedium  of  the  second  with 
the  popliteal  artery,  the  latter  forming  by  much 
the  more  free  channel  of  communication  be- 
tween the  two  vessels,  whence  the  circulation 
of  the  lower  part  of  the  limb  may  be  pre- 
served independent  of  the  communication  be- 
tween the  upper  and  lower  parts  of  the  femoral 
artery,  as  has  been  exemplified  in  the  case  of 
Sir  A.  Cooper  given  in  the  Medico-Chirur- 
gical  Transactions,  vol.  ii.;  and,  lastly,  a  com- 
munication exists  by  which  the  blood  may  be 
conveyed  from  the  arteries  of  the  trunk  into 
the  popliteal  artery  and  the  arteries  of  the  leg, 
independent  of  the  femoral  and  without  trans- 
mission through  any  part  of  its  canal. 

Hence  varieties  may  be  expected  in  the  con- 
dition of  the  femoral  artery  in  cases  of  inter- 
ruption, according  to  the  situation  of  the 
interruption,  and  the  influence  of  it  or  other 
circumstances  in  determining  the  course  which 
the  circulation  is  to  take. 

When  the  artery  is  obstructed  above  the 
origin  of  the  profunda  independent  of  aneu- 
rism, the  origin  of  that  vessel  being  free  from 
disease,  it  would  appear  that  the  trunk  of  the 
femoral  does  not  undergo  any  alteration  in  its 
capacity,  at  least  from  the  origin  of  the  pro- 
funda downward  :   when   an   interval  exists 
between    the  point  of  interruption  and  the 
origin  of  that  vessel,  the  trunk  may  be  di- 
minished for  so  much,  while  again  it  may 
continue  unaltered ;  thus  in  Sir  A.  Cooper's 
case*  already  referred  to,  the  vessel  was  found 
reduced  to  about  half  its  natural  size  between 
the  origins  of  the  epigastric  and  circumflex 
ilii  arteries  and  that  of  the  profunda,  and  from 
the  latter  it  preserved  its  ordinary  size  through 
the  remainder  of  its  course  :  in  Mr.  Norman's 
casef  on  the  other  hand,  it  was  of  its  natural 
size  in  the  interval  adverted  to,  but  inasmuch 
as  the  origin  of  the  profunda  was  obstructed 
in  the  latter  case,  it  cannot  be  considered  so 
fair  an  instance  of  the  influence  of  the  simple 
interruption  at  the  part  specified  as  the  former, 
in  which  the  femoral  artery  remained  pervious 
after  the  cure  of  the  aneurism.    It  is  hence  to 
be  inferred,  1.  that  interruption  of  the  femoral 
above  the  origin  of  the  profunda  or  of  the 
external  iliac  artery  is  not  necessarily  followed 
by  obliteration  of  the  former,  unless  it  be  of 
so  much  of  the  femoral  as  might  intervene 
between  the  interruption  and  the  origin  of  the 
profunda,  where  the  ligature  has  been  applied 
to  the  former:  2.  that  in  such  case  the  internal 
iliac  is  thenceforward  the  principal  source  from 
which  the  supply  of  blood  to  the  lower  extremity 
is  to  be  derived ;  and  that  the  profunda  artery 
through  its  inosculations  with  the  branches  of 
the  internal  iliac,  constitutes  the  chief  channel 
through  which  the  transmission  of  the  blood 
to  the  trunk  of  the  femoral  and  the  limb  takes 
place :    3.  that  the  external  iliac  artery  con- 
tributes, but  in  an  inferior  degree,  to  the  sup- 
ply of  the  limb,  when  the  interruption  is  in 
the  femoral  itself :  4.  that  the  femoral  artery 
and  its  branches  thenceforward  are  to  be  con- 

*  Guy's  Hospital  Reports, 
t  Med.-Chir.  Trans,  vol.  xx. 


ARTERY.  251 

sidered  branches  of  the  iliac  arteries,  rather  of 
the  internal  than  of  the  external,  the  trunk  of 
the  femoral  itself  being  secondary  to  its  own 
branches,  by  which  the  blood  is  transmitted 
into  it  from  the  iliacs. 

When  the  interruption  of  the  femoral  occurs 
below  the  origin  of  the  profunda,  the  oblitera- 
tion of  the  trunk  is  no  farther  necessary  than 
between  the  interruption  and  the  origin  of  the 
profunda  on  the  one  hand,  if  no  other  branch 
intervene,  and  that  of  the  next  considerable 
branch  upon  the  other.  In  such  case  the  pro- 
funda artery  becomes  the  main  channel  of  the 
circulation  through  the  lower  extremity  from  its 
origin  downward,  and  the  femoral  with  its 
branches  thenceforth  are  to  be  regarded  as 
branches  of  it. 

But  when  the  interruption  arises  from  aneu- 
rism and  the  operation  necessary  for  its  cure, 
obliteration  of  the  femoral,  to  a  greater  or  less 
extent  according  to  the  case,  for  the  most  part 
ensues:  this  appears  to  depend  upon  the  in- 
fluence, which  the  mode  of  cure  of  the  disease 
exerts  upon  the  circulation  through  the  vessel, 
for  the  coagulation  of  the  contents  of  the  sac 
being  generally  produced  by  the  interruption 
of  the  current  of  blood,  the  passage  through 
the  sac  becomes  obstructed,  and  along  with  it 
an  extent  of  the  artery  upon  both  sides  of  the 
seat  of  the  aneurism  greater  or  less  according 
to  the  disposition  of  the  adjoining  branches. 
The  extent  to  which  the  obliteration  of  the 
artery  has  been  found  to  proceed,  has  been 
different  in  different  cases,  but  the  varieties 
observed  have  been  the  following:  1.  As  re- 
gards that  part  of  the  vessel  which  is  above  the 
ligature,  when  the  femoral  artery  has  been 
tied  below  the  origin  of  the  profunda  for  po- 
pliteal aneurism,  the  vessel  has  been  found, 
when  the  ligature  has  been  applied  to  the 
lower  part  of  the  artery,  either  obliterated 
from  the  ligature  to  the  origin  of  the  pro- 
funda, as  occurred  in  the  first  subject  upon 
whom  Mr.  Hunter*  operated  for  popliteal  aneu- 
rism according  to  his  method,  or  obliterated 
upward  only  as  far  as  the  origin  of  those  mus- 
cular blanches  of  the  artery,  which  arise  below 
the  profunda  and  anastomose  with  the  articular 
arteries.  2.  When  the  ligature  has  been  ap- 
plied near  to  the  origin  of  the  piofunda,  as  in 
the  operation  of  Scarpa,  between  it  and  the 
origin  of  the  branches  alluded  to,  the  artery 
has  been  found  obliterated  from  the  point  of 
interruption  to  the  origin  of  the  profunda. 

The  condition  of  the  artery  below  the  seat 
of  the  ligature  is  equally  subject  to  variety 
according  to  circumstances,  and  is  still  more 
deserving  of  attention  than  the  former  :  it  has 
been  found  in  one  of  three  states,  either  ob- 
literated throughout  from  the  origin  of  the 
profunda  down  to  the  extremity  of  the  popli- 
teal artery,  as  occurred  in  the  case  reported 
by  Sir  A.  Cooper  in  the  Medico-Chirurgical 
Transactions,  vol.  ii.,  or  pervious  throughout 
from  the  point  of  application  of  the  ligature 
to  the  seat  of  the  aneurism,  where   it  was 

*  Transactions  of  a  Society  for  the  improve- 
ment of  Medical  and  Chirurgical  Knowledge, 
vol.  i. 


FEMORAL  ARTERY. 


obliterated.  Of  this  condition  several  in- 
stances are  cited  by  Hodgson,*  and  a  most 
remarkable  one  is  in  the  possession  of  Mr. 
Adams  of  this  city,  through  whose  liberality 
the  author  is  permitted  to  introduce  a  notice 
of  it.  It  was  obtained  from  a  patient  who  had 
been  operated  on  by  the  late  Professor  Todd, 
and  is  remarkable,  1.  because  the  operation 
had  been  performed  upon  both  limbs,  and  the 
condition  of  both  is,  as  nearly  as  may  be,  the 
same;  2.  because  the  obliteration  at  the  seat 
of  the  ligature  does  not  on  either  side  exceed 
an  inch,  on  one  not  being  more  than  half  that 
length  ;  and,  3.  because  the  artery  is  pervious 
on  both  sides  from  the  obliteration  of  the 
ligature  to  the  lower  part  of  the  popliteal 
artery,  the  obliteration  at  the  seat  of  the  dis- 
ease appearing  not  to  have  extended  beyond  it; 
and  being,  on  both  sides,  about  two  inches 
long.  Thirdly,  the  artery  has  been  found  par- 
tially and  irregularly  obliterated,  the  vessel 
being  closed  at  and  for  some  distance  below 
the  seat  of  the  ligature ;  being  then  pervious, 
the  blood  being  conveyed  into  it  by  the  in- 
osculations between  the  minor  branches  of  the 
artery  arising  below  the  interruption  and  those 
of  the  profunda  from  above ;  and  again  im- 
pervious below,  the  blood  being  conveyed 
from  it  by  similar  branches  anastomosing  with 
the  articular  arteries. 

The  effect  of  ligature  of  the  external  iliac 
upon  the  femoral  artery,  independent  of  the 
influence  of  aneurism,  has  been  already  ad- 
verted to.  That  effect  is  liable  to  be  modified 
by  the  presence  of  the  disease;  thus  in  a  case 
related  by  Sir  A.  Cooper  in  the  fourth  volume 
of  the  Medieo-Chirurgical  Transactions,  in 
which  the  iliac  was  tied  for  aneurism  of  the 
femoral  artery  at  the  middle  of  the  thigh,  the 
latter  vessel  was  obliterated  from  the  origin 
of  the  profunda  downward.  The  case,  re- 
corded by  Mr.  Norman,  already  referred  to, 
in  which  the  external  iliac  was  also  tied, 
presents  another  remarkable  modification :  in 
it  the  femoral  remained  pervious,  but  the  root 
of  the  profunda  was  obliterated,  while  its 
branches  were  open. 

Operative  relations  of  the  femoral  artery. — 
The  femoral  artery  may  be  the  subject  of  ope- 
ration at  any  part  of  its  course,  there  being 
nothing  either  in  its  situation  or  relations  to 
forbid  the  exposure  of  it  at  any  point,  if  cir- 
cumstances should  require  it.  All  parts,  how- 
ever, are  not  equally  eligible,  the  vessel  being 
in  some  situations  more  deeply  situate,  covered 
by  a  greater  number  and  depth  of  parts,  and 
its  relations  more  complicated  than  at  others. 
It  has  been  taken  up  in  each  of  the  three 
stages  into  which  its  course  has  been  divided, 
and  the  operations,  which  may  according  to 
circumstances  be  performed  upon  it,  may  with 
advantage  be  referred  lo  those.  The  propriety 
of  thus  distinguishing  them  will  appear  in  a 
strong  light,  when  tho.^e  modifications,  which 
the  anatomical  relations  of  the  vessel  may 
justify,  shall  have  been  discussed,  as  also  from 
the  history  of  the  operations,  which  have  been 

*  Op.  cit.  278,  9. 


and  are  proposed  to  be  performed  upon  the 
femoral  artery. 

In  its  first  stage  the  vessel  may  be  tied 
at  two  points,  viz.  either  above  or  below  the 
origin  of  the  profunda  artery :  the  operation 
at  the  former  point,  being  performed  under 
circumstances  different  from  those  in  which 
that  at  the  latter  is  admissible,  may  be  con- 
sidered apart  from  the  others,  and  the  de- 
tail of  it  be  postponed  until  they  have  been 
disposed  of ;  while  the  operation  in  the  second 
case,  and  those  in  the  second  and  third  stages 
have  been  at  different  times  performed  for  the 
same  purpose — the  cure  of  popliteal  aneurism 
— and  therefore  a  comparison  of  their  several 
details  and  advantages  merits  attention.  The 
situation  in  which  the  femoral  artery  was  first 
taken  up  for  popliteal  aneurism  is  the  third 
stage  of  its  course :  here  it  was  tied,  as  is 
generally  known,  by  J.  Hunter.  In  his  ope- 
ration Hunter  made  "  an  incision  on  the  an- 
terior and  inner  part  of  the  thigh  rather  below 
its  middle;"  i.e.  in  the  third  stage ;  "  which  in- 
cision was  continued  obliquely  across  the  inner 
edge  of  the  sartorius  muscle  and  made  large :" 
the  other  steps  of  his  operation  it  is  not  neces- 
sary at  present  to  particularize  ;  the  author 
would  only  remark,  as  a  matter  of  history,  that 
Hunter's  application  of  ligatures  has  been  mis- 
understood :  he  applied  in  bis  first  operation 
four  ligatures  to  the  artery,  and  it  is  com- 
monly, if  not  generally,  said  that  they  were 
drawn  with  various  degrees  of  tightness  ;  but 
such  was  not  the  case,  they  were  tied  all 
equally  tight :  the  account  given  in  the  report 
of  the  operation  being,  "  the  artery  was  now 
tied  by  both  these  ligatures,"  viz.  the  two  upper, 
"  but  so  slightly  as  only  to  compress  the  sides 
together.  A  similar  application  of  ligatures 
was  made  a  little  lower.  The  reason  for  hav- 
ing four  ligatures  was  to  compress  such  a 
length  of  artery,  as  might  make  up  for  the 
want  of  tightness,  it  being  wished  to  avoid 
great  pressure  on  the  vessel  at  any  one  part." 

The  artery  may  be  and  has  been  frequently 
taken  up  in  the  middle  stage,  and  the  ope* 
ration,  as  described  in  several  surgical  works, 
will  be  found  to  belong  to,  if  not  to  be  in- 
tended for,  that  stage.  During  its  two  latter 
stages  the  artery  is  covered  by  the  sartorius : 
in  its  uppermost  it  is  not  covered  by  the  muscle, 
and  consequently  if  it  be  necessary  to  displace 
the  muscle  to  bring  the  artery  into  view  above 
the  last  stage,  it  must  be  in  the  middle  one, 
and  in  the  account  of  the  operation  given  by 
some  of  the  highest  authorities,  the  displace- 
ment of  the  sartorius  is  stated  as  one  of  the 
steps.  This  the  author  refers  to  not  in  a  spirit 
of  criticism,  but  in  order  to  mark  more 
strongly  the  distinction  between  the  operations 
at  the  several  stages,  and  to  direct  attention  to 
the  advantages  possessed  by  that  in  the  first 
over  the  others;  more  particularly  since  de- 
scriptions, which  in  strictness  apply  to  the 
operation  in  the  middle  stage,  and  at  a  part 
of  the  artery's  course  below  the  first,  may  be 
found  so  put  forward  that  the  operations  at  the 
two  points  must  be  confounded;  and  thus  the 
advantages  contemplated  by  the  proposer  of 


FEMORAL  ARTERY. 


253 


the  latter  be  lost.  It  will  be  recollected  that 
in  the  two  inferior  stages  the  artery  is  covered 
by  the  sartorius  and  by  two  laminae  of  the 
fascia  lata,  between  which  the  muscle  is 
situate :  the  vessel  is,  therefore,  similarly  cir- 
cumstanced in  this  particular  throughout  both, 
but  in  some  other  important  respects  the  re- 
lations of  the  artery  are  different.  1.  In  its 
middle  stage  the  vessel  is  nearer  to  the  anterior 
plane  of  the  limb.  2.  The  deep  layer  of  fascia, 
by  which  it  is  covered,  is  far  less  thick  and 
strong,  particularly  at  its  upper  part.  3.  The 
artery  is  not  so  completely  covered  by  the  sar- 
torius; and  for  those  reasons  the  vessel  may 
be  more  easily  reached  from  before.  These 
constitute  the  principal  anatomical  conside- 
rations why  the  middle  stage  should  be  pre- 
ferred to  the  lower  for  operation,  but,  since  it 
is  at  times  requisite  to  tie  the  vessel  in  its  last 
stage,  it  is  necessary  to  examine  the  influence 
which  its  anatomical  relations  may  have  upon 
the  conduct  of  the  operation  at  that  part. 
1.  The  greater  depth  of  the  artery  from  the 
anterior  surface  of  the  limb  renders  a  more 
extended  incision  necessary  :  in  cutting  upon 
arteries  "  the  centre  of  the  incision  should  be," 
as  directed  by  Guthrie,  "  if  possible  directly 
over  that  part  of  the  artery  on  which  it  is  in- 
tended to  apply  the  ligature."  In  the  case  of 
the  femoral  artery  in  its  third  stage,  the  length 
of  the  incision  should  not  be  less  than  from 
four  to  five  inches  according  to  the  volume  of 
the  limb ;  its  direction  should  correspond  to 
that  of  the  sartorius,  but  it  must  be  varied 
somewhat  according  to  the  side  of  the  muscle 
upon  which  the  operator  may  purpose  to  seek 
the  vessel.  It  should  commence  somewhat 
below  the  middle  of  the  thigh,  and  be  con- 
tinued as  much  upon  the  lower  as  upon  the 
middle  third  of  the  limb.  2.  The  artery  is 
situate,  in  its  third  stage,  nearer  to  the  outer 
than  the  inner  margin  of  the  sartorius,  and  the 
more  so  the  nearer  to  its  termination ;  hence  it 
may  be  exposed  with  greater  ease  and  cer- 
tainty by  cutting  upon  the  outer  edge  of  the 
muscle  and  displacing  it  inward.  Hunter,  in 
his  operations,  selected  the  inner  margin,  and 
displaced  it  forward  and  outward;  but  this 
proceeding  is  attended  with  disadvantages. 
1.  The  saphena  vein  is  more  in  the  way  and 
exposed  to  danger  of  being  divided  since  it 
lies  at  this  part,  along  or  near  the  inner  mar- 
gin of  the  sartorius.  2.  The  muscle  lying  more 
to  the  inner  than  the  outer  side  of  the  artery 
must  be  more  displaced,  and  the  depth  of  the 
wound  for  the  same  reason  greater  when  the 
vessel  is  sought  from  its  inside.*  3.  The  ope- 
ration must  be  more  inconvenient  and  em- 
barrassing, as  well  because  of  the  former 
difficulties  as  because  it  must  be  performed 
more  from  the  inside  of  the  limb,  and  from 
within  outward,  than  in  the  method  by  the 

*  The  contrary  is  maintained  by  Lisfranc  and 
others  ;  but,  according  to  the  experience  of  the 
author,  without  sufficient  reason.  He  has  care- 
fully compared  the  depth  of  the  wounds  as  made 
upon  the  opposite  sides  of  the  muscle,  and  in  the 
subjects  of  examination  that  by  the  inside  appeared 
to  him  the  deeper. 


outer  margin  of  the  sartorius.  Those  objec- 
tions are  avoided  by  cutting  upon  the  outer 
edge  of  the  muscle,  against  which,  however, 
it  has  been  advanced  that  in  that  method  the 
vastus  internus  may  be  mistaken  for  the  sar- 
torius, and  that  the  wound  being  made  from 
before,  there  is  not  a  depending  and  ready 
outlet  afforded  to  matter  should  it  form,  while 
by  the  other  there  is.  The  former  of  these 
objections  cannot  cany  much  weight,  and  for 
the  second  the  best  plan  for  obviating  the 
dangers  of  inflammation  and  suppuration  is, 
as  much  as  possible,  to  render  them  unneces- 
sary, which  is  best  accomplished  by  selecting 
that  method  by  which  the  artery  may  be  ex- 
posed most  easily,  and  with  least  disturbance 
to  the  parts  in  its  vicinity.  To  the  writer, 
therefore,  it  seems  that  the  method  by  the 
outer  margin  of  the  sartorius,  which  appears 
to  have  been  suggested  by  Hutchison,  is  the 
more  eligible  in  the  operation  for  taking  up 
the  femoral  in  its  third  stage.  2.  The  great 
thickness  and  strength  of  the  anterior  wall 
of  the  femoral  canal  both  increase  the  dif- 
ficulty of  opening  the  canal,  and  render  it 
desirable  that  that  structure  should  be  freely 
divided  for  the  double  purpose  of  facilitating 
the  taking  up  of  the  artery,  and  preventing 
the  injurious  effect  which  must  be  produced 
by  the  confinement  caused  by  the  structure  in 
question  in  the  event  of  inflammation  extend- 
ing along  the  vessel.  3.  The  relation  of  the 
vein  to  the  artery  at  this  part,  viz.  posterior 
and  external,  will  make  it  more  safe  to  pass 
the  needle  round  the  latter  from  without  than 
from  the  outside ;  this,  however,  is  a  rule 
which  cannot  be  strictly  adhered  to,  for  the 
direction  in  which  the  instrument  shall  be 
passed  must  be  varied  according  to  circum- 
stances ;  it  would  be  difficult  to  pass  it  from 
the  outside  in  case  the  artery  were  exposed 
from  the  inside  of  the  sartorius ;  but  attention 
to  the  caution  demanded  by  the  position  of 
the  vein  is,  for  this  reason,  only  the  more 
necessary.  4.  The  saphenus  nerve  being  here 
within  the  femoral  canal  is  to  be  carefully 
avoided  ;  it  will  be  so  with  certainty,  if  the 
needle  be  carried  from  the  outside  5  The 
mistake  of  confounding  the  superficial  sune 
nor  internal  articular  artery  with  the  femoral 
must  be  also  avoided*  This  mistake,  which 
has  occurred,  ought  not  however  to  occur 
again  ,„  the  hands  of  a  well-informed  surgeon, 
for  the  possibility  of  it  ought  not  to  be  lost 
sight  of  in  operations  at  the  lower  part  of  the 
thigh;  and  it  may  be  easily  avoided  by  re- 
collecting, first,  that  the  femoral  itself  is 
within  the  femoral  canal,  and  therefore  that 
any  vessel,  which  presents  before  the  division 
of  the  anterior  wall  of  the  canal,  which  is  so 
remarkably  thick  in  this  situation  that  it  can 
hardly  be  overlooked,  cannot  be  the  one  which 
is  sought  for;  and,  secondly,  that  the  course  of 
the  branch  within  the  canal,  after  its  origin  is 
very  short,  and  therefore  that  in  case  of°do'ubt 
the  vessel  which  presents,  must,  if  the  arti- 
cular, conduct  us  directly  to  the  trunk  itself, 

*  See  that  vessel. 


254 


FEMORAL  ARTERY. 


when  followed  upward  for  a  very  short  dis- 
tance. 

Lastly,  the  structures  to  be  divided  or  put 
aside  in  order  to  expose  the  artery  are, — 1.  the 
skin;  2.  the  subcutaneous  cellular  stratum; 
3.  the  superficial  lamina  of  the  fascia  lata, 
forming  the  anterior  wall  of  the  sheath  of  the 
sartorius;  4.  the  sartorius  itself;  5.  the  deep 
lamina  of  the  fascia  forming  the  posterior  wall 
of  the  sheath  of  the  sartorius,  and  the  anterior 
wall  of  the  femoral  canal ;  and,  6.  the  proper 
sheath  of  the  vessels. 

The  difference  between  the  anatomical  re- 
lations of  the  operation  in  the  middle  and 
inferior  stages  of  the  artery  depends  upon  the 
modifications  to  be  observed  in  the  relations 
of  the  vessel  at  the  two  points,  and  also  in 
some  of  the  parts  concerned.  The  number 
and  order  of  the  structures  interposed  between 
the  surface  and  the  artery  are  the  same  as  in 
the  third,  but  their  disposition  and  relations 
differ  in  some  important  particulars  so  much 
as  to  authorize  a  difference  in  the  proceedings 
to  be  adopted,  and  to  justify  a  preference  in 
favour  of  the  former.  1.  The  artery  is  nearer 
to  the  anterior  surface  of  the  limb,  and  the 
more  so  the  nearer  to  the  commencement  of 
the  stage :  it  is  therefore  more  easily  reached 
and  in  the  same  proportion.  2.  It  is  nearer 
to  the  inner  than  the  outer  margin  of  the  sar- 
torius, and,  in  like  manner,  the  more  so,  the 
nearer  to  its  upper  extremity ;  and  hence  it 
may  be  brought  into  view  with  more  ease  and 
with  less  disturbance  of  the  muscle  by  dis- 
placing its  inner  margin  outward,  than  its 
outer  inward. 

The  latter  proceeding  is  advocated  by  Hut- 
chison for  the  purpose  of  avoiding  the  sa- 
phena  vein  and  the  lymphatics.  That  the 
vein  will  be  effectually  secured  from  danger 
by  cutting  upon  the  outside  of  the  sartorius 
will  be  at  once  admitted ;  but  it  appears  to  the 
author  that  the  advantage  contemplated  will 
be  more  than  counterbalanced  by  the  dis- 
advantages attending  it,  and  on  the  other  hand 
that  the  proceeding  is  not  necessary:  for,  1. 
if  the  outer  margin  of  the  muscle  be  cut  upon 
in  the  middle  of  the  vessel,  the  incision  must 
be  made  considerably  external  to  the  line  of 
the  artery's  course,  and  thereby  the  guide  to 
the  vessel  otherwise  afforded  by  that  line  must 
be  lost,  and  uncertainty  and  consequently 
embarrassment  be  likely  to  ensue  in  seeking 
for  the  artery  after  having  displaced  the  muscle. 
2.  Much  more  disturbance  and  violence  are 
likely  to  be  inflicted  upon  the  artery  and  the 
adjoining  parts  by  the  plan  in  question,  in- 
asmuch as  the  vessel  is  so  much  nearer  to  the 
inner  than  the  outer  margin  of  the  muscle  ; 
in  consequence  of  which  the  muscle  must  be 
displaced  to  a  much  greater  extent  in  proceed- 
ing from  without  inward,  and  the  obstruction 
offered  by  it  to  the  performance  of  the  other 
steps  of  the  operation  must  lead  to  greater 
violence  either  to  the  artery  or  to  the  muscle  ; 
and  afterward  a  valvular  wound  must  be  left, 
a  circumstance  very  unfavourable  in  the  event 
of  the  occurrence  of  inflammation  and  sup- 
puration in  the  vicinity  of  the  track  of  the 


vessel,  and  those  objections  are  the  stronger 
because  the  artery  is  usually  sought  at  the 
upper  part  of  the  stage,  where  it  is  but  little 
overlapped  by  the  muscle.  On  the  other  hand 
the  saphena  vein  ought  not  to  be  endangered 
in  the  operation,  for  it  is  situate  so  far  internal 
to  the  artery  that  the  incision  ought  not  to  fall 
upon  it.  The  case  is  different  from  that  of  cut- 
ting upon  the  inner  margin  of  the  sartorius 
during  the  third  stage  of  the  vessel ;  for  there 
the  vein  is  for  the  most  part  close  to  the  edge 
of  the  muscle,  and  the  wound  must  be  in- 
clined in  depth  from  within  outward,  by  which 
direction  the  vein  is  interposed  between  the 
surface  and  the  artery ;  whereas,  in  the  second 
stage,  whether  the  operator,  in  proceeding  by 
the  inner  margin  of  the  muscle,  cut  directly 
upon  the  artery's  course  or  upon  the  edge  of 
the  sartorius,  there  is  sufficient  space  between 
it  and  the  vein  to  leave  the  latter  safe.  The 
course  of  the  artery  may  be  crossed  at  any  part 
by  the  superficial  femoral  veins,  as  has  been 
explained,  and  they,  if  they  present,  will  be 
in  danger  of  division ;  but  this  inconvenience 
would  not  be  removed  by  the  plan  in  question, 
whereas  both  it  and  the  danger  to  the  saphena 
may  be  avoided  by  an  easier  and  less  ob- 
jectionable proceeding  than  that  of  cutting 
upon  the  outer  edge  of  the  sartorius,  viz.  1. 
by  ascertaining,  through  means  of  pressure, 
the  situation  and  course  of  the  veins ;  and,  2. 
by  proceeding  with  somewhat  more  caution, 
where  there  is  reason  to  expect  their  presence, 
dividing  first  only  the  skin  and  continuing  the 
incision  through  the  subcutaneous  structure, 
not  by  a  single  stroke,  by  which  the  vein  if  in 
the  way  must  necessarily  be  divided,  but  gra- 
dually, until  the  vessel  has  been  exposed  and 
drawn  aside.  It  seems  therefore  to  the  author 
not  only  unnecessary,  but  very  objectionable 
to  cut  upon  the  outer  margin  of  the  sartorius, 
in  exposing  the  femoral  artery  above  the  mid- 
dle of  the  thigh.  3.  The  anterior  wall  of  the 
femoral  canal  is  much  thinner  than  in  the 
third  stage,  and  therefore  more  easily  ma- 
naged. 4.  The  vein  is  directly  behind  the 
artery,  and  therefore  the  needle  may  be  passed 
with  equal  safety  from  either  side,  according 
to  circumstances :  in  operating  by  the  inner 
margin  of  the  sartorius  it  will  be  more  easily 
done  from  the  inside  :  the  position  of  the  vein 
and  its  close  connection  to  the  artery  render 
it  especially  necessary  that  the  extremity  of 
the  needle  be  kept  in  contact  with  the  artery 
in  being  carried  behind  it.  The  saphenus 
nerve  requires  the  same  attention  as  in  the 
third  stage. 

But  the  situation  in  which  it  is  at  present 
generally  considered  most  eligible  to  expose 
the  artery  for  the  application  of  a  ligature,  when 
circumstances  do  not  forbid  a  choice,  is  that 
recommended  by  Scarpa,  viz.  in  the  upper 
third  of  the  thigh,  and  in  the  first  stage  of  the 
artery's  course  as  described  in  the  account  of 
the  anatomical  relations  of  the  vessel.  In  his 
description  of  the  details  of  the  operation, 
Scarpa  directs  thus  :  "  The  surgeon  pressing 
with  his  fore-finger  will  explore  the  course  of 
the  superficial  femoral  artery,  from  the  crural 


FEMORAL  ARTERY. 


255 


arch  downward,  and  when  he  comes  to  the 
place  where  he  does  not  feel  any  more,  or  very 
confusedly,  the  vibration  of  the  artery,  he  will 
there  fix  with  his  eye  the  inferior  angle  or  ex- 
tremity of  the  incision  which  he  proposes  to 
make  for  bringing  the  artery  into  view.  This 
lower  angle  of  the  incision  will  fall  nearly  on 
the  internal  margin  of  the  sartorius  muscle, 
just  where  this  muscle  crosses  the  course  of  the 
femoral  artery.   A  little  more  than  three  inches 
above  the  place  pointed  out,  the  surgeon  will 
begin  his  incision  and  carry  it  along  the  thigh 
in  a  slightly  oblique  line  from  without  inwards, 
following  the  course  of  the  femoral  artery  as 
far  as  the  point  fixed  with  the  eye."    By  this 
incision  the  skin  and  cellular  substance  are  to 
be  divided,  and  the  fascia  lata  exposed,  "  then 
with  another  stroke  of  the  bistoury,  with  his 
hand  free  and  unsupported,  or  upon  a  furrowed 
probe,  he  will  divide  along  the  thigh,  and  in  the 
same  direction  as  the  external  wound  the  fascia, 
and  introducing  the  fore-finger  of  his  left  hand 
into  the  bottom  of  the  incision,  he  will  imme- 
diately feel  the  strong  beating  of  the  artery,  and 
this  without  the  necessity  of  removing  the  in- 
ternal margin  of  the  sartorius  from  its  position, 
or  at  least  very  little.    With  the  point  of  the 
fore-finger  of  the  left  hand  already  touching  the 
artery,  the  surgeon  will  separate  it  from  its 
lateral  connexions  and  from  the  vein;"  after 
which  the  ligature  is  to  be  carried  round  it  by 
means  of  a  blunt  aneurism-needle.  The  author 
has  introduced  the  preceding  account  ia  order 
to  fix  the  precise  situation  of  the  operation  as 
performed  by  Scarpa,  because  it  appears  to  him 
that  it  has  been  to  a  certain  degree  lost  sight  of, 
and   also  to  direct  attention   more  strongly 
to  the  advantage  proposed  by  that  distin- 
guished surgeon  in  the  adoption  of  the  method 
which  he  has  recommended.    A  very  brief 
consideration  of  the  descriptions  given  by  se- 
veral writers*  of  the  proceedings  to  be  adopted 
in  the  operation  of  taking  up  the  artery  in  the 
upper  part  of  the  thigh  will  suffice  to  shew 
either  that   Scarpa's  method  has  been  con- 
founded more  or  less  with  the  operation  at  a 
lower  point,  or  that  its  advantages  have  been 
disregarded:  thus,  while  it  is  stated  that  the 
part  of  the  limb  in  which  the  femoral  artery 
can  be  tied  with  the  greatest  facility  is  between 
four  and  five  inches  below  Poupart's  ligament, 
and  which  is  Scarpa's  point,f  the  displacement 
of  the  sartorius  is  accounted  a  part  of  the  ope- 
ration, and  it  has  even  been  debated  whether 
the  incision  should  not  be  made  on  the  outer 
edge  of  the  sartorius,  and  the  artery  exposed 
by  drawing  the  muscle  inward ;  but  the  dis- 
placement of  the  sartorius  is  not  only  not  a 
necessary  part  of  Scarpa's  plan,  but  is  that 
particular  the  avoidance  of  which  he  proposed 
to  himself  by  the  method  he  selected  ;  from 
whence  it  will  appear  that  the  operation,  as 
described  in  the  accounts  alluded  to,  refers, 
strictly  speaking,  to  the  second  and  not  to  the 
first  third  of  the  vessel's  course,  within  the 
latter  of  which  it  must  be  performed  in  order 

*  Hodgson,  &c. 

t  The  distance  at  which  the  sartorius  crosses  the 
artery  varies  according  to  the  stature. 


to  avoid  the  sartorius.  .  The  structures  to  be 
divided  in  this  operation  are,  1.  the  skin,  2. 
the  subcutaneous  cellular  structure,  3.  the 
fascia  lata,  forming  the  anterior  wall  of  the 
femoral  canal.    The  extent  of  the  superficial 
incisions  need  not  exceed  three  inches,  com- 
mencing above  either  according  to  the  rule  of 
Scarpa  or  about  two  inches  below  Poupart's 
ligament :  the  direction  in  which  they  should 
be  made  ought  to  correspond  as  nearly  as  pos- 
sible with  the  course  of  the  artery.  The  extent 
to  which  the  fascia  lata  is  to  be  divided  is 
stated  differently  by  different  writers  :  by  some 
it  is  directed  to  be  divided  to  the  extent  of 
about  an  inch  :  the  direction  of  Scarpa  is  not 
precise  upon  the  point  in  the  text,  though  it  is 
plain  that  he  intended  it  should  be  divided  to 
a  much  greater  length  than  an  inch,  but  in  a 
note  it  is  strongly  insisted  that  the  division  of 
the  fascia  should  correspond  in  extent  to  that 
of  the  external  wound.    Two  reasons  present 
for  this  :  1.  greater  facility  in  the  performance 
of  the  operation,  and  less  disturbance  in  con- 
sequence to  the  artery ;  2.  the  avoiding  the 
injurious  effects  which  must  be  produced  by 
the  confinement  consequent  upon  too  limited 
a  division  of  the  fascia  in  the  event  of  the 
supervention  of  inflammation.     It  cannot  be 
doubted  that  a  division  of  an  inch  is  altogether 
too  short  to  meet  those  considerations,  and  that 
the  fascia  ought  to  be  divided  to  a  greater  ex- 
tent ;  on  the  other  hand  it  does  not  appear  that 
advantage  would  be  gained  by  so  free  a  divi- 
sion as  that  recommended  by  Scarpa ;  and  the 
rule  of  Guthrie  seems  the  best  calculated  to  ac- 
complish the  ends  in  view :  he  advises  the  fascia 
to  be  divided  for  the  space  of  two  inches.  The 
division  may  be  effected  either  with  or  without 
the  assistance  of  the  director.    It  will  be  well 
to  recollect  here  that,  at  the  point  at  which  the 
sartorius  is  about  to  overlap  the  artery,  a  du- 
plicature  of  the  fascia  takes  place  in  order  to 
enclose  the  muscle,  and  hence  that,  if  the 
opening  of  the  canal  be  attempted  at  the  lower 
extremity  of  the  stage,  and  close  to  the  muscle, 
two  layers  of  the  fascia  may  require  to  be  di- 
vided before  this  purpose  can  be  accomplished. 
The  femoral  canal  having  been  opened  by  the 
division  of  the  fascia  lata,  the  next  step  in  the 
operation  is  the  division  of  the  proper  sheath 
of  the  vessels  and  the  insulation  of  the  artery. 
Previous  to  this,  should  the  internal  genicular 
nerve  be  found  to  cross  the  canal  superficial  to 
the  artery  at  the  part,  at  which  the  vessel  is 
to  be  detached  from  the  contiguous  parts,  it 
should  be  separated  and  drawn  outward.  The 
insulation  of  the  artery  Scarpa  recommends  to 
be  effected  with  the  finger,  raising  the  vessel 
from  the  wound  even  along  with  the  vein  if 
necessary;  such  a  proceeding,  however,  must 
be  very  objectionable,  as  inflicting  great  dis- 
turbance and  violence  upon  the  artery.    It  is 
to  be  recollected  that  in  order  to  insulate  the 
artery  it  is  necessary  to  divide  or  lacerate  the 
investment,  which  immediately  encloses  the 
two  vessels  and  connects  them  to  each  other, 
and  which  has  been  elsewhere  denominated 
the  femoral  sheath  ;  this,  though  thin,  is  dense, 
and  is  to  be  expected  to  offer  resistance  to  the 


256 


FEMORAL  ARTERY. 


separation  of  the  artery  from  the  vein :  the  best 
method  of  effecting  this,  as  it  seems  to  the 
author,  will  be,  after  having  opened  the  sheath 
directly  over  the  centre  of  the  artery  either  by 
a  touch  of  the  knife  or  first  nipping  up  a  part 
of  it  with  the  forceps  ;  making  an  aperture 
into  it  with  the  blade  of  the  knife  held  horizon- 
tally, and  extending  the  opening  upon  a  di- 
rector to  the  length  of  "  three-quarters  or  an 
inch,"  as  recommended  by  Guthrie  ;  then  with 
the  forceps  to  take  hold  of  each  portion  of  the 
sheath  in  turn  and  drawing  it  to  its  own  side, 
outward  or  inward  as  the  case  may  be,  to  de- 
tach the  artery  from  it  with  the  extremity  of  a 
director  or  of  the  aneurism-needle,  moving  the 
extremity  of  the  instrument  gently  upward  and 
downward  at  the  same  time  that  the  vessel  is 
carried,  by  means  of  it,  in  the  opposite  direc- 
tion from  the  side  of  the  sheath  which  is  in 
the  forceps  ;  by  this  proceeding  the  artery  may 
be  easily  and  safely  insulated  almost,  if  not 
quite,  round,  and  with  little  if  any  disturbance 
to  it.    That  done,  the  needle  and  ligature  may 
be  carried  round  the  artery :  the  performance 
of  this,  which  is  the  most  delicate  step  in  the 
operation,  will  be  found  much  facilitated  by 
the  separation  of  the  artery  as  recommended  ; 
in  fact,  little  more  will  then  remain  than  to 
pass  the  needle,  the  passage  having  been  al- 
ready opened.    In  doing  so  it  will  be  well  to 
hold  the  inner  portion  of  the  sheath,  with  the 
forceps,  inward  and  backward,  by  which  the 
vein  will  be  drawn  away  from  the  artery,  and 
at  the  same  time  to  insinuate  the  blunt  extre- 
mity of  the  aneurism-needle  round  the  artery 
from  within  outward,  because  of  the  situation 
of  the  vein,  moving  it,  if  any  obstruction  be 
encountered,  upward  and  downward,  while  it 
is  also  carried  forward,  and  bearing  the  artery 
somewhat  outward  with  it  at  the  same  time ; 
when  the  extremity  of  the  needle  has  appeared 
on  the  outside  of  the  artery  it  may  be  liberated, 
if  necessary,  by  a  touch  of  the  scalpel  upon  it. 
In  the  execution  of  this  manoeuvre  two  acci- 
dents are  to  be  avoided,  viz.  injury  of  the 
vein,  and  inclusion  of  the  saphenus  nerve : 
the  close  juxta-position  and  attachment  of  the 
former  to  the  artery  render  much  care  neces- 
sary to  leave  it  uninjured;  but  the  proceeding 
recommended  will,  if  carefully  executed,  cer- 
tainly preserve  it  from  being  wounded.  The 
saphenus  nerve  is  here  on  the  outside  of  the 
artery,  and  might  be  included  within  the  liga- 
ture if  the  extremity  of  the  needle  were  carried 
too  far  outward  ;  the  operator  should  therefore 
assure  himself,  before  tying  the  ligature,  that 
the  nerve  has  not  been  included ;  but  the  risk 
of  this  accident  ought  not  to  be  great  at  this 
part  of  the  artery's  course,  certainly  not  so 
much  so  as  at  a  lower  point,  inasmuch  as  the 
nerve  has  as  yet  hardly  entered  the  femoral 
canal,  and  is  therefore  separated  from  the  ar- 
tery by  more  or  less  of  its  outer  wall;  and  with 
the  precautions  recommended  in  insulating  the 
vessel  and  passing  the  ligature  it  will  almost 
certainly  be  excluded  at  every  part :  the  possi- 
bility of  the  accident  is,  however,  not  to  be 
lost  sight  of.    The  needle  having  been  carried 
round  the  artery,  the  ligature  is  to  be  taken 


hold  of  with  the  forceps,  and  one  end  drawn 
out,  after  which  the  needle  is  to  be  withdrawn. 
The  advantages  of  the  part  chosen  by  Scarpa 
for  this  operation  are  numerous  and  obvious  : 
1.  the  artery  is  nearer  to  the  surface  and  has 
fewer  coverings;  there  is  therefore  less  to  be 
divided  in  order  to  bring  it  into  view;  2.  the 
vessel  being  more  superficial,  its  pulsations  can 
be  more  distinctly  felt  and  its  course  ascer- 
tained previous  to  operation,  a  guide  wanting 
in  the  lower  parts  of  the  thigh ;  3.  "  the  ope- 
ration is  done,"  as  Guthrie  observes,  "  on  that 
part  of  the  artery  which  is  not  covered  by 
muscle,  and  all  interference  with  the  sartorius 
is  avoided  :  this  method  obviates  all  discussion 
as  to  placing  the  ligature  on  the  outside  of  the 
muscle."    The  plan  of  cutting  upon  the  out- 
side of  the  sartorius  in  the  upper  stage  of  the 
artery  must  be,  if  contemplated  by  any,  a  pro- 
ceeding hardly  defensible  in  the  ordinary  dis- 
position of  the  muscle,  for  all  the  reasons  ad- 
vanced already  against  its  use  in  the  second 
stage  apply  with  much  greater  force  to  it  in  the 
former  case ;  but  it  is  at  the  same  time  to  be 
observed  that  the  distance  of  the  point  at  which 
the  muscle  crosses  the  femoral  artery  is  not  ab- 
solutely regular,  and  that  great  deviation  in 
this  respect  might  render  it  necessary  even  to 
cut  upon  the  outer  margin  of  the  muscle  in 
order  to  expose  the  artery  in  the  first  third  of 
its  course.    The  distance  from  Poupart's  liga- 
ment at  which  the  muscle  ordinarily  crosses  is, 
according  to  the  stature,  from  three  and  a  half 
to  five  inches,  but  it  may  in  certain  cases  be 
found  to  cross  so  much  sooner  that  the  artery 
could  not  be  exposed  below  the  origin  of  the 
profunda  without  displacing  the  muscle  ;  thus 
Burns*  mentions  that  he  has  seen,  in  conse- 
quence of  malformation  of  the  pelvis,  the  artery 
covered  by  the  muscle,  before  it  had  reached 
two  inches  below  the  ligament,  and  the  author 
has  witnessed  the  same  from  retraction  of  the 
thighs,  consequent  apparently  upon  long  con- 
finement to  bed ;  in  the  latter  case  it  would 
certainly  have  been  more  easy  to  expose  the 
vessel  from  the  outer  than  from  the  inner  side 
of  the  muscle ;  but  such  cases  are  to  be  re- 
garded only  as  exceptions  to  be  borne  in  mind, 
but  not  to  influence  our  general  conduct. 

4.  The  performance  of  the  last  and  most  deli- 
cate parts  of  the  operation  must  be  much  more 
easy  and  less  embarrassed,  the  interference  of 
the  sartorius  being  avoided;  while,  on  the  other 
hand,  all  apprehension  on  account  of  the  pro- 
funda is  removed,  since  that  vessel  seldom,  if 
ever,  arises  farther  than  two  inches  from  Pou- 
part's ligament,  and  the  course  of  the  case  after 
operation  is  more  likely  to  be  favourable  and 
exempt  from  untoward  occurrences,  since  much 
less  violence  must  be  done,  and  the  superven- 
tion of  injurious  inflammation  or  its  conse- 
quences thereby  prevented. 

The  operation  for  taking  up  the  femoral  ar- 
tery above  the  origin  of  the  profunda  is  not  often 
required,  and,  except  in  case  of  wound,  may  pro- 
bably give  place  altogether  to  that  of  tying  the 
external  iliac  :  it  presents  no  advantage  over 

*  Op.  cit.  p.  321. 


FIBRINE. 


257 


the  latter,  it  does  not  promise  more  successful 
results :  should  secondary  hemorrhage  succeed 
to  it,  there  is  little  prospect  that  the  ligature  of 
the  iliac  would  afterward  succeed,  and  the 
uncertainty  existing  with  regard  to  the  point  of 
origin  of  the  profunda  raises  a  very  strong  ob- 
jection against  it,  inasmuch  as  we  cannot  know 
whether  the  origin  of  that  vessel  be  above, 
below,  or  at  the  point  at  which  the  ligature  is 
to  be  applied :  it  is  further  exposed  to  the 
difficulty,  before  adverted  to,  which  is  likely 
to  arise  in  cases  of  high  origin  of  the  profunda, 
in  which  that  vessel  may  be  taken  for  the 
femoral,  and  thus  another  source  of  embar- 
rassment be  encountered. 

In  the  performance  of  it  the  following  struc- 
tures will  present :  1.  the  skin  ;  2.  the  subcu- 
taneous cellular  stratum  along  with  the  inguinal 
glands  and  the  superficial  inguinal  vessels  of 
the  latter :  those  which  are  most  exposed  to  be 
divided  are  the  superficial  epigastric  and  its 
branches  ;  the  superficial  anterior  iliac  and  the 
superficial  pudics  may  be  encountered,  but 
they  are  less  likely;  3.  the  superficial  lamina 
of  the  iliac  portion  of  the  fascia  lata;  and  4. 
the  prolongation  of  the  fascia  transversalis, 
which  forms  the  front  of  the  femoral  sheath. 

An  incision  three  inches  long  will  suffice  ;  it 
should  commence  above  Poupart's  ligament, 
and  be  continued  in  the  line  of  the  vessel  for 
two  inches  below  it. 

If  the  superficial  vessels  bleed,  on  division, 
so  much  as  to  interfere  with  the  course  of  the 
operation,  they  should  be  at  once  secured ; 
otherwise  they  will  probably  cease  themselves, 
and  give  no  further  trouble. 

The  lymphatic  glands,  if  in  the  way  of  the 
incisions,  may  be  either  held  aside  or  removed. 
The  fascia  lata  and  sheath  may  be  treated  in 
the  same  manner  as  in  the  other  operations 
described ;  they  can  be  easily  distinguished  in 
consequence  of  the  thin  stratum  of  fat  which  is 
usually  interposed. 

The  insulation  of  the  artery  and  the  passage 
of  the  needle  require  the  same  precautions  as 
in  the  operations  at  other  parts  of  the  vessel's 
course.  The  vein  being  placed  along  the  inside 
of  the  artery  the  needle  should  be  passed  from 
that  side. 

The  crural  nerve  and  its  branches  are  here 
altogether  safe,  as  they  lie  without  the  femoral 
canal,  but,  as  has  been  before  pointed  out,  the 
crural  branch  of  the  genito-crural  nerve  may 
be  included  in  the  ligature;  it  will  be  most 
certainly  avoided  by  the  careful  insulation  of 
the  artery:  the  operator  should  also  assure 
himself,  before  tying  the  ligature,  that  no  fila- 
ment is  enclosed. 

Should  two  arteries  present,  as  described  in 
the  anatomy  of  the  profunda,  and  a  question 
arise  as  to  which  is  the  femoral,  the  criteria 
pointed  out  will  enable  the  operator  to  decide 
(see  profunda  artery ) ;  and  the  difficulty  will, 
almost  certainly,  be  altogether  avoided  by  cut- 
ting directly  upon  the  centre  line  of  the  femoral 
as  ascertained  by  its  pulsations. 

Operation  on  the  profunda  artery. — From 
the  anatomical  details  it  follows  that  in  the  ma- 
jority of  cases  the  profunda  is  situate,  in  the 

VOL.  II, 


first  stage  of  its  course  at  least,  at  the  outer  or 
iliac  side  of  the  femoral  artery,  though  upon 
a  plane  posterior  to  that  vessel :  it  has  also,  at 
the  same  time,  the  same  coverings,  differing 
only  in  being  contained  in  a  sheath  proper  to 
itself;  and  hence,  if  necessary,  the  profunda 
might  be  reached  in  that  situation  by  an  opera- 
tion similar  to  that  for  exposing  the  femoral 
itself  at  the  same  place,  in  which  much  advan- 
tage would  be  obtained  by  first  exposing  the 
latter  vessel,  and  following  it  as  a  guide  to 
the  origin  of  the  former ;  which,  if  in  its  usual 
situation,  will  be  exposed  by  displacing  the 
femoral  inward,  and  then  the  proper  sheath  of 
the  profunda  should  be  opened  to  a  certain  ex- 
tent, in  order  to  allow  the  application  of  the 
ligature  at  a  sufficient  distance  from  the  origin 
of  the  vessel.  But  in  the  inferior  stages  of  its 
course  it  may  be  laid  down,  as  a  general  rule, 
that  it  cannot  be  reached  from  the  front  of  the 
thigh,  inasmuch  as,  with  the  exception  of  those 
cases  in  which  it  is  throughout  external  to  the 
femoral,  and  in  which,  from  its  deep  position, 
and  the  want  of  a  guide  to  its  exact  situation, 
the  rule  will  yet  equally  apply,  it  is  not  only 
more  deeply  seated,  but  it  is  separated  from 
the  anterior  surface  of  the  limb  by  the  super- 
ficial femoral  artery,  and  by  the  femoral,  pro- 
funda, and  circumflex  veins,  as  well  as  by  the 
coverings  of  the  femoral  vessels,  and  lastly  by 
the  adductor  longus  muscle.  In  any  case,  did 
circumstances  render  necessary  the  attempt  to 
tie  the  profunda,  it  would  be  an  operation  in 
which  much  uncertainty  and  difficulty  must  be 
anticipated,  in  consequence  of  the  varieties 
presented  by  that  artery  in  its  origin  and 
course. 

For  Bibliography  see  ANATOMY  (INTRODUC- 
TION), and  A  RTEU  Y. 

(  B.  Alcock.) 

FIBRINE,  {Ywfibrine;  Germ.  Faserstoff.) 
Under  this  name  physiologists  and  chemists 
have  generally  described  the  animal  proximate 
principle  constituting  that  part  of  muscular 
fibre  which  is  insoluble  in  cold  water,  and  that 
portion  of  the  coagulum  of  blood  which  re- 
mains after  the  removal  of  its  colouring  matter. 

The  fibrine  of  blood  is  best  obtained  by 
stirring  a  quantity  of  fresh-drawn  blood  with  a 
piece  of  wood,  to  which  the  coagulum  adheres, 
and  may  afterwards  be  washed  in  large  and 
repeated  portions  of  water  till  it  loses  its  co- 
louring particles,  and  remains  in  the  form  of 
a  buff-coloured,  fibrous,  and  somewhat  elastic 
substance ;  this  may  then  be  partially  dried  by 
pressure  between  folds  of  blotting-paper,  di- 
gested in  alcohol  to  remove  fat,  and  then  care- 
fully dried,  during  which  process  it  loses  about 
three-fourths  of  its  weight,  and  becomes  brittle 
and  of  a  yellowish  colour:  it  is  insipid  and  in- 
odorous. In  cold  water  it  slowly  resumes  its 
original  appearance  but  does  not  dissolve : 
when,  however,  it  is  subjected  to  the  long- 
continued  action  of  boiling  water  it  shrinks 
and  becomes  friable,  and  a  portion  of  a  newly- 
formed  substance  is  at  the  same  time  taken  up 
by  the  water,  which  gives  it  a  yellowish  colour 
and  the  smell  and  taste  of  boiled  meat,  and 

s 


258 


FIBRINE. 


which,  when  obtained  by  evaporation,  is  brittle, 
yellow,  and  again  soluble  in  water :  this  solu- 
tion is  rendered  turbid  by  infusion  of  galls, 
but  the  precipitate  differs  from  that  yielded  by 
gelatin,  and  appears  to  be  a  distinct  product. 
The  insoluble  residue  has  lost  its  original  cha- 
racters; it  no  longer  gelatinises  with  acids  or 
alkalies,  and  is  insoluble  in  acetic  acid  and  in 
caustic  ammonia. 

The  action  of  acids  and  alkalies  upon  the 
fibrine  of  blood  has  been  studied  in  detail  by 
Berzelius  and  others ;  the  following  is  an  ab- 
stract of  their  results. * 

All  the  acids,  except  the  nitric,  render  fibrine 
transparent  and  gelatinous :  the  diluted  acids 
cause  it  to  shrink  up.  In  sulphuric  acid  it 
acquires  the  appearance  of  a  bulky  yellow  jelly, 
which  immediately  shrinks  upon  the  addition 
of  water,  and  is  a  combination  of  the  acid  and 
fib  rine ;  when  well  washed  upon  a  filter  it  gra- 
dually becomes  transparent  and  soluble,  and 
in  that  state  is  a  neutral  sulphate  of  fibrine.  It 
is  again  rendered  opaque  by  dilute  sulphuric 
acid,  and  is  precipitated  from  its  aqueous  solu- 
tion by  that  acid  in  the  form  of  white  flakes, 
which  appear  to  be  a  supersulphate.  When 
fibrine  is  heated  in  sulphuric  acid,  both  are 
decomposed,  the  mass  blackens,  and  sulphu- 
rous acid  is  evolved.  If  the  colouring  matter 
has  not  been  entirely  washed  out  of  the  fibrine, 
the  sulphuric  solution  is  of  a  brown  or  purple 
colour. 

Nitric  acid  communicates  a  yellow  colour  to 
fibrine,  and,  if  cold  and  dilute,  combines  with 
it  to  form  a  neutral  nitrate,  analogous  to  the 
sulphate  When  fibrine  is  digested  in  nitric 
acid,  nitrogen  is  evolved,  and  its  composition 
considerably  changed,  as  we  shall  more  parti- 
cularly mention  in  describing  the  action  of  this 
acid  on  muscular  fibre. 

Muriatic  acid  gelatinises  fibrine  and  then 
gradually  dissolves  it,  forming  a  dark  blue 
liquid,  or  purple  and  violet,  if  retaining  any 
haematosin.  This  solution,  when  diluted  with 
water,  deposits  a  white  muriate  of  fibrine, 
which,  like  the  sulphate,  gelatinises  when  the 
excess  of  acid  is  washed  away,  and  becomes 
soluble,  and  is  again  thrown  down  from  its 
aqueous  solution  by  excess  of  acid.  The  blue 
liquid,  after  the  separation  of  the  precipitate  by 
dilution,  retains  its  colour,  but  loses  it  when 
saturated  with  ammonia,  and  with  excess  of 
ammonia  becomes  yellow.  Fibrine  digested 
in  dilute  muriatic  acid  is  converted  into  the 
same  white  compound  as  that  precipitated 
by  water  from  the  concentrated  muriatic  solu- 
tion. Wrhen  boiled  in  the  acid,  nitrogen  is 
evolved,  and  a  solution  is  obtained,  which,  after 
the  saturation  of  the  acid,  is  precipitated  by 
infusion  of  galls,  but  not  by  alkali  or  ferrocy- 
anuret  of  potassium ;  on  evaporating  the  solution 
to  dryness  a  dark  brown  saline  mass  remains, 
so  that  the  fibrine  appears  to  have  undergone 
some  decomposition. 

*  Berzelius,  Lehrbuch  der  Thier-Chemie,  Woh- 
ler's  German  translation.  Dresden,  1831.  See 
also  Medico-Chirurgical  Transactions,  vol.  iii. 
p.  201. 


A  solution  of  recently-fused  phosphoric  acid 
acts  upon  fibrine  in  the  same  way  as  the  sul- 
phuric acid  ;  but  if  the  acid  solution  has  been 
kept  for  some  weeks,  the  fibrine  then  forms 
with  it  a  soluble  jelly,  which  is  not  precipitated 
by  excess  of  acid. 

Concentrated  acetic  acid  converts  fibrine  into 
a  jelly  easily  soluble  in  warm  water.  When 
this  solution  is  boiled, a  little  nitrogen  is  evolved, 
but  nothing  is  precipitated  ;  when  gently  eva- 
porated, it  gelatinises,  and  leaves,  on  desic- 
cation, an  opaque  insoluble  residue.  The  other 
acids  added  to  this  acetic  solution  produce 
precipitates  which  are  compounds  of  fibrine 
with  the  added  acid.  Fibrine  is  also  preci- 
pitated from  the  acetic  solution  by  caustic  pot- 
assa,  but  is  redissolved  by  excess  of  alkali. 

The  acetic  solution  of  fibrine  is  precipitated 
in  white  flakes  by  ferrocyanuret  of  potassium  : 
this  precipitate,  when  dried,  appears  to  be  a 
compound  of  fibrine  with  cyanuret  of  iron 
and  hydrocyanic  acid;  it  is  insoluble  in  dilute 
acids,  but  is  decomposed  by  caustic  alkalis, 
which  abstract  the  cyanuret  of  iron  and  hydro- 
cyanic acid,  and  the  remaining  fibrine  first 
gelatinises  and  then  dissolves.  100  parts  of 
this  compound,  carefully  dried  at  167°,  and 
then  incinerated  in  a  weighed  platinum  cru- 
cible, gave  2.8  red  oxide  of  iron,=7.8  of  the 
combination  of  cyanuret  of  iron  with  hydro- 
cyanic acid;  whence  it  follows  that  92.2  of 
fibrine  were  contained  in  the  white  precipitated 
compound. 

Caustic  potassa,  even  much  diluted,  dissolves 
fibrine.     If  the  solution  is  very  dilute,  the 
fibrine  gradually  forms  a  bulky  jelly,  which, 
heated  in  a  close  vessel  to  about  130°,  dissolves 
into  a  pale  yellow  liquid,  not  quite  transparent, 
and  which  soon  clogs  a  filter.    The  yellow  tint 
appears  to  arise  from  the  presence  of  a  small 
portion  of  adhering  haematosin.    When  this 
alkaline  solution  is  saturated  by  muriatic  or 
acetic  acid,  it  exhales  a  peculiar  fetid  odour  and 
blackens  silver,  announcing  the  presence  of 
sulphur,  so  that  the  animal  matter  seems  to 
have  suffered  some  slight  change.    It  is  stated 
by  Berzelius  that  fibrine  is  capable  of  neutral- 
izing the  alkali,  and  that  such  neutral  com- 
pound   may  be  obtained  by  dissolving  the 
fibrine  in  the  alkaline  solution,  and  adding 
acetic  acid  till  it  begins  to  occasion  a  precipi- 
tate ;  the  filtered  liquid  is  then  perfectly  neu- 
tral, but  the  potassa  bears  a  very  small  propor- 
tion to  the  fibrine.    This  neutral  solution,  he 
says,  much  resembles  white  of  egg,  and  is 
coagulated  by  alcohol  and  acids,  though  not  by 
heat.    Gently  evaporated,  it  gelatinises,  and, 
when  dry,  assumes  the  appearance  of  albumen 
dried  without  coagulation.     In  this  state  it 
dissolves  in  warm  water,  and  is  first  thrown 
down,  and  then  redissolved  by  the  acids  when 
added  in  excess.    Alcohol  throws  down  nearly 
the  whole  of  the  fibrine  from  its  neutral  alkaline 
solution  :  if  there  be  excess  of  alkali,  much  of 
the  fibrine  is  retained.   Mr.  Hatchett  found  that 
fibrine,  when  digested  in  strong  caustic  potassa, 
evolved  ammonia  and  yielded  a  species  of  soap; 
acids  occasion  a  precipitate  in  this  solution 
which  is  altered  fibrine,  for  it  neither  gelati- 


FIBRINE. 


259 


hises  nor  dissolves  in  acetic  acid:  ammonia  acts 
as  potassa,  but  less  energetically. 

When  fibrine  is  digested  in  solution  of  per- 
sulphate of  iron,  or  of  copper,  or  of  perchlo- 
ride  of  mercury,  it  combines  with  those  salts, 
shrinks  up,  and  loses  all  tendency  to  putre- 
faction. When  the  alkaline  solution  of  fibrine 
is  decomposed  by  metallic  salts,  the  precipitate 
consists  of  the  fibrine  in  combination  with  the 
metallic  oxide;  some  of  these  compounds  are 
soluble  in  caustic  potassa. 

Tannin  combines  with  fibrine,  and  occasions 
a  precipitate  both  in  its  alkaline  and  acid  solu- 
tions: the  tanned  fibrine  resists  putrefaction. 

The  ultimate  composition  of  fibrine  has  been 
determined  by  Gay  Lussac  and  Thenard,  and 
by  Michaelis,  who  made  a  comparative  ana- 
lysis of  that  of  arterial  and  venous  blood  :  the 
following  are  their  results:  — 

Gay  Lussac  Michaelis. 
and  Thenard.      Arterial.  Venous. 

Nitrogen  ..19.934  17.587  17.267 

Carbon    ..53.360  51.374  50.440 

Hydrogen     7-021   7.254   8.228 

Oxygen  ..19.685  23.785  24.065 


100.000  100.000  100.000 

The  mean  of  these  results  gives  nearly  the  fol- 
lowing atomic  composition :  — 

Atoms.     Equivalents.  Theory. 

Nitrogen   1  14  19.72 

Carbon  6  36  50.70 

Hydrogen  5   5   7.04 

Oxygen  2  16  22.54 


1  71  100.00 

In  reference  to  this  atomic  estimate,  which 
is  suggested  by  Leopold  Gmelin,*  Berzelius 
observes,  that  from  the  feeble  saturating  power 
of  fibrine,  its  equivalent  number  is  probably 
very  high,  that  is,  that  it  includes  a  larger 
number  of  simple  atoms;  but  as  we  have  at 
present  no  accurate  means  of  determining  its 
combining  proportion  or  saturating  power,  its 
atomic  constitution  cannot  be  satisfactorily 
determined.  Moreover,  it  appears  that  in  the 
above  analyses  the  fat  was  not  separated,  nor  is 
any  notice  taken  of  the  minute  portion  of  sul- 
phur, the  presence  of  which  has  been  above 
adverted  to. 

When  Berzelius  first  obtained  fat  from  fibrine 
by  digesting  it  in  alcohol  and  in  ether,  he  con- 
cluded that  it  arose  from  the  decomposition  of 
a  portion  of  the  fibrine  by  those  agents  ;  that  it 
was  a  product  and  not  an  educt;  but  the  sub- 
sequent experiments  of  Chevreul  leave  no 
doubt  that  the  fat  exists  ready  formed  in  the 
blood.  This  fat  is  very  soluble  in  alcohol,  and 
the  solution  is  slightly  acid;  when  it  is  burned, 
the  ash,  instead  of  being  acid,  like  that  of  the 
fatty  matter  of  the  brain,  is  alkaline,  whence 
it  appears  that  it  existed  saponified,  or  partly 
so,  in  the  blood. 

Another  important  variety  of  fibrine  is  that 
which  constitutes  muscular  fibre,  but  it  is  so 
interwoven  with  the  nerves  and  vessels  and 
cellular  and  adipose  membrane,  that  its  pro- 
perties are  probably  always  more  or  less  modi- 

*  Handbuch  der  Theoretischen  Chemie. 


fied  by  foreign  matters.  The  colour  of  muscles 
appears  to  depend  upon  that  of  the  blood  in 
their  capillary  vessels;  and  their  moisture  is 
referable  to  water,  which  may  be  expelled  by 
drying  them  upon  a  water-bath,  when  they  lose 
upon  an  average  75  per  cent.  If  muscular 
fibre  in  thin  slices  is  washed  with  water  till 
all  soluble  matters  are  removed,  the  residue, 
when  carefully  dried,  does  not  exceed  17  or  18 
per  cent,  of  the  original  weight. 

To  obtain  the  fibrine  of  a  muscle,  it  must  be 
finely  minced  and  washed  in  repeated  portions 
of  water  at  60°  or  70°,  till  all  colouring  and 
soluble  substances  are  withdrawn,  and  till  the 
residue  is  colourless,  insipid,  and  inodorous; 
it  is  then  strongly  pressed  between  folds  of 
linen,  which  renders  it  semitransparent  and 
pulverulent.  Berzelius  observes  that  in  this 
state  it  becomes  so  strongly  electro-positive 
when  triturated,  that  the  particles  repel  each 
other  and  adhere  to  the  mortar,  and  that  it  stil 
retains  fat  which  is  separable  by  alcohol  or 
ether.  When  long  boiled  in  water,  it  shrinks, 
hardens,  and  yields  a  portion  of  gelatine  de- 
rived from  the  insterstitial  cellular  membrane; 
the  fibrine  itself  is  also  modified  by  the  con- 
tinued action  of  boiling  water,  and  loses  its 
solubility  in  acetic  acid,  which,  when  digested 
with  it  in  its  previous  state,  forms  a  gelatinous 
mass  soluble  in  water,  but  slightly  turbid  from 
the  presence  of  fat  and  a  portion  of  insoluble 
membrane,  derived  apparently  from  the  vessels 
which  pervaded  the  original  muscle.  It  is 
soluble  in  diluted  caustic  potassa,  and  precipi- 
tated by  excess  of  muriatic  acid,  the  precipitate 
being  a  compound  of  fibrine  with  excess  of 
muriatic  acid,  and  which,  when  washed  with 
distilled  water,  becomes  gelatinous  and  soluble, 
being  reduced  to  the  state  of  a  neutral  muriate 
of  fibrine.* 

When  the  fibrine  of  muscle  is  mixed  with 
its  weight  of  sulphuric  acid,  it  swells  and  dis- 
solves, and,  when  gently  heated,  a  little  fat 
rises  to  the  surface  and  may  be  separated :  if 
the  mass  is  then  diluted  with  twice  its  weight 
of  water  and  boiled  for  nine  hours,  (occasion- 
ally replacing  the  loss  by  evaporation,)  am- 
monia is  formed,  which  combines  with  the 
acid,  and  on  saturating  it  with  carbonate  of 
lime,  filtering,  and  evaporating  to  dryness,  a 
yellow  residue  remains,  consisting  of  three 
distinct  products:  two  of  these  are  taken  up 
by  digestion  in  boiling  alcohol  of  the  specific 
gravity  of  .845,  and  are  obtained  upon  evapo- 
ration ;  this  residue,  treated  with  alcohol  of  the 
specific  gravity  of  .830,  communicates  to  it  (1) 
a  portion  of  a  peculiar  extractive  matter,  and 
the  insoluble  remainder  (2)  is  white,  soluble  in 
water  and  crystallisable,  and  has  been  called 
by  Braconnot  leucine.^    It  fuses  at  212°,  ex- 

*  It  will  be  observed,  by  reference  to  the  article 
ALBUMEN,  that  that  principle  and  fibrine,  if  not 
identical,  are  very  closely  allied,  and  appear  rather 
to  differ  in  organization  than  in  essential  chemical 
characters  :  accordingly  the  fibrine  of  the  blood  may 
be  considered  as  a  modification  of  seralbumen,  and 
that  of  muscular  fibre  as  little  differing  from  the 
fibrine  of  the  blood. 

t  Ann.  de  Chim.  et  Phys.  xiii.  119. 

S  2 


260 


FIBRQ-CARTILAGE. 


haling  the  odour  of  roasted  meat,  and  partly 
sublimes :  it  is  difficultly  soluble  in  alcohol. 
It  dissolves  in  nitric  acid,  and  yields  on  eva- 
poration a  white  crystalline  compound,  the 
nitro-lcucic  acid.  The  portion  of  the  original 
residue  which  is  insoluble  in  alcohol  (3)  is 
yellow,  and  its  aqueous  solution  is  precipi- 
tated by  infusion  of  galls,  subacetate  of  lead, 
nitrate  of  mercury,  and  persulphate  of  iron. 
It  appears  therefore  that  the  products  of  the 
action  of  sulphuric  acid  upon  the  fibrine  of 
muscle,  are,  1,  an  extractive  matter  soluble  in 
alcohol;  2.  leucine;  and  3.  extractive,  inso- 
luble in  alcohol  but  soluble  in  water. 

(W.  T.  Brande.) 

FIBRO-CARTILAGE,  (Cartilago  liga- 
ment osav  .fibrosa ;  Fr.  Tissu  fibrocartilagineux ; 
Germ.  Faser-Knorpel  oder  Band-Knorpel ). — 
As  early  as  the  time  of  Galen  we  find  certain 
organs  distinguished  by  the  appellation  vtv^o- 
Xov&guh*;  cvv§tap.oi,  and  Fallopius  uses  a 
similar  term,  namely,  chondrosyndesmos,  as 
denoting  a  substance  distinct  from  true  carti- 
lage. Haase*  also,  who  wrote  in  1747,  speaks 
of  two  structures  different  from  true  cartilage, 
under  the  names  of  cartilagines  ligamentoste 
and  cartilagines  mixta.  Bichat  likewise  recog- 
nised a  class  of  tissues  distinct  from  pure 
cartilage,  and  by  him  it  would  appear  that  the 
name  fibro-cartilage  was  first  employed. 

It  is  evident  that  no  organ  should  be  classed 
under  the  head  of  fibro-cartilage  unless  it  con- 
sist distinctly  of  fibrous  tissue  and  cartilage 
intermixed,  and  thus  combine  not  only  the 
structure  but  the  properties  of  both,  the  strength 
and  power  of  resistance  of  the  one,  and  the  elas- 
ticity of  the  other;  nevertheless,  we  shall  find, 
in  examining  the  various  structures  which  are 
admitted  by  anatomists  to  be  fibro-cartilaginous, 
that  the  fibrous  tissue  predominates  in  such  a 
manner  as  to  justify  Beclard  in  regarding  fibro- 
cartilage  as  a  portion  of  the  ligamentous  struc- 
ture, which  might  be  designated  cartilaginiform 
ligamentous  organs.  The  distinction  was  fully 
admitted  too  by  Mr.  Hunter  in  reference  to 
the  texture  of  the  so-called  inter-articular  car- 
tilages. Speaking  of  that  of  the  temporo- 
maxillary  articulation,  he  says,  "  its  texture  is 
ligamento-cartilaginous."t 

The  classification  of  fibro-cartilages  adopted 
by  Meckel  seems  to  me  to  be  the  best;  he 
arranges  them  under  three  classes:— 1.  Those 
whose  two  surfaces  are  free  wholly  or  at  least 
in  great  part,  and  whose  edges  are  united  to 
the  synovial  capsules,  the  moveable  fibro-car- 
tilages of  articulation.  2.  Those  which  are 
free  by  one  of  their  surfaces,  and  which  adhere 
to  bone  or  tendon  by  the  other :  these  are 
the  fibro-cartilages  of  tendinous  sheaths,  or 
those  which  limit  the  articular  cavities,  and  may 
be  called  fibro-cartilages  of  circumference  or 
cylindrical  fibro-cartilages.  3.  Those  whose  two 
surfaces  are  adherent  in  their  entire  extent  to 
the  bones  between  which  they  are  placed. 

*  De  fabrica  cartilaginum,  Lipsiae,  1747. 
t  Hunter  on  the  Teeth. 


Of  these  classes  the  first  and  third  and  some 
of  those  which  come  under  the  second  belong 
to  the  articulations.    Their  forms  and  structure 
have  already  been  described  in  the  article 
Articulation.    I  may  here,  however,  notice 
the  statement  of  Weber*  in  regard  to  the  discs 
interposed  between  the  vertebrae,  which  have 
been  generally  regarded  as  fibro-cartilaginous. 
This  anatomist  denies  that  they  exhibit  any 
intermixture  of  cartilaginous  substance,  and 
considers  that  this  is  rendered  manifest  by 
stretching  the  intervertebral  substance,  by  which 
it  becomes  reduced  to  a  fibrous  expansion 
C sehnighautige Masse ) ;  he  consequently  places 
these  intervertebral  discs  among  the  fibrous 
tissues.    There  can  be  no  doubt  that  the  cir- 
cumference of  each  disc  is  purely  fibrous,  and 
that  the  concentric  vertical  lamellae  of  fibrous 
tissue  extend  for  some  distance  towards  the 
centre  of  the  disc;  but  I  am  at  a  loss  to  per- 
ceive any  resemblance  to  fibrous  tissues  in  the 
soft  and  elastic,  and  yielding  substance  which 
forms  the  centre.    It  seems  to  me  that  this 
texture  can  only  be  regarded  as  a  modified 
form  of  cartilage,  differing  in  its  want  of 
density  from  the  ordinary  cartilage,  whether 
permanent  or  temporary.    The  intervertebral 
substance,  however,  to  whatever  texture  it  may 
ultimately  be  decided  to  belong,  does  present 
very  striking  differences  from  the  other  organs 
which  are  placed  among  the  fibro-cartilages. 

It  is  in  the  fibro-cartilages  of  the  second 
class  that  we  see  most  uniformly  the  inter- 
mixture of  the  fibrous  and  cartilaginous  texture, 
although  here,  likewise,  the  fibrous  tissue  pre- 
dominates over  the  cartilaginous. 

The  fibro-cartilages  are  remarkable  for  their 
great  flexibility,  in  virtue  of  which  they  are 
enabled  to  resist  fracture,  and  this  property  is 
no  doubt  owing  to  the  intermixture  of  fibrous 
tissue;  cartilaginous  laminae,  on  the  other  hand, 
are  easily  broken  by  bending,  and  many  of 
them  exhibit  a  fibrous  appearance  on  the  surface 
of  the  fracture,  which,  however,  arises  from 
the  irregular  fracture  and  not  from  the  existence 
of  fibres.  Fibro-cartilages  are  of  a  dull  white 
colour  and  quite  opaque ;  they  have  no  perichon- 
drium, but  are  either  in  immediate  connexion 
with  bone,  being  inserted  into  it  by  their  fibrous 
burjdles,  or  are  covered  by  the  synovial  mem- 
brane of  the  joint  in  which  they  are  enclosed. 
Their  physical  and  vital  properties  are  those 
which  belong  to  pure  cartilage  and  to  fibrous 
tissue.  Their  force  of  cohesion  is  very  great 
and  surpasses  even  that  of  bones.  They  are 
more  vascular  than  pure  cartilage,  but  in  the 
natural  state  they  admit  very  few  vessels  carry- 
ing red  blood.  Bichat  examined  the  fibro- 
cartilages  in  an  animal  which  died  asphyxiated, 
and  found  these  organs  not  injected.  The 
remarkable  manner  in  which  fibro-cartilages 
resist  the  influence  of  a  compressing  tumour,  as 
a  pulsating  aneurism,  is  well  known;  while  by 
such  means  the  bodies  of  the  vertebrae  are 
completely  destroyed,  the  intervertebral  discs 
will  remain  quite  uninjured. 

*  Einige  Beobachtungen  iiber  das  Structur  der 
Knorpel  und  Faser-Knorpel,  in  Meckel's  Archiv 
for  1827. 


F1BR0-CARTILAGE. 


261 


Fibro-cartilages  dry  readily  when  exposed 
to  the  air  and  become  of  a  deep  yellow  colour; 
they  resist  for  a  very  long  time,  many  months, 
the  influence  of  maceration,  and  by  long-con- 
tinued boiling  they  become  converted  into  a 
gelatinous  substance.  Their  chemical  compo- 
sition is  said  to  be  made  up  of  albumen,  phos- 
phate of  lime,  chlorurets  of  sodium  and  of 
potassium,  sulphate  of  lime  and  other  salts, 
usually  found  in  animal  textures. 

The  microscopic  characters  of  fibro-cartilage 
do  not  seem  to  have  been  investigated  with  the 
same  care  as  those  of  many  other  textures.  I 
have  examined  by  transmitted  light  very  thin 
slices  of  the  fibro-cartilages  in  the  knee  and 
temporo-maxillary  joint,  and  the  appearance 
presented  was  uniformly  that  of  a  very  compli- 
cated cellular  structure,  composed  of  minute 
meshes,  very  irregular  in  size  and  shape.  In 
examining  the  intervertebral  substance  I  have 
distinctly  seen,  towards  the  circumference  of 
the  d  ise,  those  fine  and  uniform  cylindrical 
fibres  with  wave-like  bendings  described  and 
figured  by  Jordan  j*  but  towards  the  centre  the 
texture  exhibited  the  cellular  appearance  with 
larger  meshes,  similar  to  that  seen  in  the  fibro- 
cartilages  of  the  knee  and  joint  of  the  lower 
jaw.f 

Of  the  structures  placed  by  Bichat  among 
the  fibro-cartilages,  some  have  been  considered 
by  Meckel,  Beclard,  Weber,  and  other  anato- 
mists to  be  pure  cartilage,  and  as  it  seems  to 
me  with  much  justice.  These  are  the  membra- 
niform  cartilages  of  the  external  ear,  Eustachian 
tube,  nose,  larynx,  trachea,  and  eyelids.  The 
cartilaginous  nature  of  most  of  these  textures 
is  very  apparent  upon  carefully  dissecting  off 
the  dense  perichondrium  which  invests  them, 
and  to  which,  doubtless,  they  owe  their  flexi- 
bility, or  more  correctly,  by  which  they  are 
prevented  from  being  fractured  under  the 
influence  of  a  bending  force.  Careful  micro- 
scopic observation  may  assist  materially  in 
affording  marks  indicative  of  pure  cartilage ; 
and  as  the  observations  of  Purkinje,  Miiller, 
and  Miescher  approach  in  some  degree  to  this 
object,  I  have  thought  it  not  foreign  to  the 
subject  of  this  article  to  introduce  here  some 
account  of  these  researches.  The  results  of 
Purkinje's  examinations  of  the  minute  structure 
of  bone  as  well  as  cartilage  were  published  in 
the  year  1834  in  an  inaugural  dissertation  by 
Deutsch.I  Miiller  and  Miescher  have  further 
investigated  the  subject  and  confirmed  the 
statements  of  Purkinje.§ 

In  examining  thin  slices  of  cartilage  under 

*  Uber  das  Gewebe  der  Tunica  Dartos,  &c. 
Muller's  Archiv,  1834. 

+  Miescher  states  that  in  infants  this  part  of  the 
intervertebral  substance  is  composed  of  a  pellucid 
mucus,  which,  under  the  microscope,  sometimes 
exhibits  some  of  the  cartilaginous  corpuscles  to  be 
noticed  in  a  subsequent  part  of  this  article,  but  in 
adults  it  is  composed  of  adipose  tissue! 

t  De  penitiori  ossium  structura.  Diss,  inaug. 
Vratisl.  1834. 

§  Vid.  Miiller,  Vergleichende  Anatomic  der 
Myxinoiden,  Berlin,  1835,  and  Miescher,  de  ossium 
genes,  structura,  et  vita.  Diss,  inaug.  Berol. 
1836.  b 


Fie.  139. 


the  microscope  by  transmitted  light,  Purkinje 
observed  numerous  little  bodies  irregularly  dis- 
persed through  its  texture,  of  a  round  or  oval 
form,  and  somewhat  less  transparent  than  the 
intervening  substance.  The  annexed  figure, 
taken  from  Miiller's  work 
already  referred  to,  gives 
a  representation  of  these 
bodies :  they  are  deno- 
minated by  Purkinje 
cartilaginous  corpuscles 
(Knorpel  Korperchen). 
In  some  cases,  as  in  tem- 
porary cartilage,  they  ap^ 
peared  to  consist  of  mi- 
nute granules ;  they  pre- 
sented this  appearance 
likewise  in  the  cartilagi- 
nous part  of  the  cranium 
of  a  frog.  In  the  costal 
cartilages  they  were  solid, 
and  in  the  cartilaginous 
fishes,  as  in  the  lamprey, 
their  contents  were  of  a 
soft  or  fluid  consistence.  According  to  Purkinje, 
these  corpuscles  are  found  in  the  temporary 
cartilages,  in  permanent  cartilage,  in  cartilage 
which  becomes  ossified  in  old  age,  as  that  of 
the  ribs  and  larynx,  in  the  cartilages  of  the 
nose  and  septum  narium. 

According  to  Miescher  there  are  two  kinds 
of  permanent  cartilage,  differing  from  each 
other  as  well  by  external  characters  as  by  in- 
ternal structure ;  one  of  these  scarcely  differs 
at  all  from  the  temporary  cartilage,  the  other 
is  very  dissimilar  in  structure.  The  first  class 
is  at  once  distinguished  by  its  azure  whiteness 
and  by  its  pellucid  brightness,  not  unlike  that 
of  mother-of-pearl,  from  the  second,  which  is 
yellowish  in  colour,  not  pellucid,  and  spongy 
in  texture.  To  the  former  class  belong  all 
articular  cartilages,  those  of  the  ribs,*  that  of 
the  ensiform  cartilage  of  the  sternum,  the  thy- 
roid, cricoid,  and  arytenoid  cartilages,  and 
those  of  the  septum  narium  and  aire  nasi. 
All  the  cartilages  of  this  class  are  characterized 
by  containing  the  microscopic  corpuscles  above 
described,  variously  arranged  in  each  form  of 
cartilage,  in  some  placed  in  clusters,  in  others 
closely  aggregated  together  in  one  part  and 
separated  in  another.  It  is  interesting  to  ob- 
serve that  the  temporary  cartilage  universally 
contains  these  corpuscles,  and  as  all  the  carti- 
lages we  have  described  are  more  or  less  prone 
to  ossification  in  advanced  age,  we  are  led  to 
the  inference,  that  these  corpuscles  thus  de- 
posited are  characteristic  of  cartilage  which 
admits  of  becoming  ossified.f 


*  Sic  Miescher. 

t  The  cartilages  most  liable  to  ossify  by  the  pro- 
gress  of  age  in  man,  are  those  which  most  fre- 
quently exhibit,  after  a  certain  period,  a  per- 
manently ossified  condition  in  some  of  the  inferior 
classes  of  animals.  Thus,  in  birds,  and  among 
mammals,  in monotremata, cheiroptera, and  cetacca, 
the  cartilages  of  the  ribs  show  a  very  early  dis- 
position to  ossify.  In  birds  the  laryngeal  cartilages 
are  very  apt  to  ossify,  and  in  swine  and  oxen  par 
tial  ossifications  of  the  same  cartilages  are  not 


262 


FIBRO-CARTILAGE. 


To  the  second  class  of  cartilages  belong 
those  of  the  external  ear,  of  the  epiglottis,  and 
the  capitula  of  Santo  rini,  connected  with  the 
apices  of  the  arytenoid  cartilages,  which  in  the 
ruminants,  the  hog  tribe,  and  others,  are  of  con- 
siderable size.  Besides  the  characters  already 
mentioned  which  distinguish  this  class  of  car- 
tilage from  the  former,  the  microscope  dis- 
closes some  further  differences.  "  Placed 
under  the  microscope,"  says  Miescher,  "  the 
cartilages  of  this  class  present  a  very  delicate 
network,  opaque,  composed  of  small  round 
meshes  which  are  filled  by  a  uniform,  pellucid 
substance,  and  each  generally  contains  a  single 
corpuscle  somewhat  roundish  or  oblong."  The 
cartilages  that  belong  to  this  class  are  con- 
trasted with  those  of  the  former,  as  being  never 
transformed  into  bone. 

I  may  add,  that  in  my  own  examinations  of 
pure  cartilage,  from  the  skeletons  of  cartila- 
ginous fishes,  and  from  the  human  subject, 
I  have  found  the  foregoing  descriptions  correct. 
The  cartilaginous  corpuscles  may  be  always 
seen  under  the  compound  microscope,  with  an 
object  glass  of  a  quarter  of  an  inch  or  an  eighth 
of  an  inch  focus. 

In  man  and  the  mammalia,  the  following 
structures  may  be  enumerated  as  belonging  to 
the  class  of  fibro-cartilages:  1.  The  so-called 
inter-articular  cartilages  in  the  knee,  sterno- 
clavicular, and  temporo-maxillary  joints  ;  that 
in  the  wrist-joint  seems  to  me  to  be  purely 
cartilaginous.  2.  The  fibro-cartilages  of  cir- 
cumference, as  in  the  hip  and  shoulder-joints. 
3.  The  fibro-cartilages  of  tendons,  which  ulti- 
timately  form  sesamoid  bones,  and  those  of 
tendinous  sheaths.  4.  According  to  Miescher, 
the  tarsal  cartilages.  5.  The  inter-osseous 
lamina;,  as  those  between  the  pubes,  pieces  of 
the  sacrum  and  coccyx,  and,  in  a  modified  form, 
the  intervertebral  substance. 

In  the  inferior  vertebrata  and  in  the  inver- 
tebrata  fibro-cartilage  gradually  disappears : 
in  the  former,  the  intervertebral  substance 
seems  to  be  the  only  remnant  of  it,  excepting 
perhaps  the  sclerotic  coat  of  the  eye  in  some 
fishes.  In  the  invertebrata,  Blainville  considers 
the  three  tubercular  teeth  of  the  leech  as  being 
fibro-cartilaginous. 

Morbid  conditions  of  fibro-cartilage. — As 
fibro-cartilage  in  its  physical  and  vital  pro- 
perties so  nearly  approaches  pure  cartilage,  it  is 
reasonable  to  expect  a  great  similarity  in  the 
phenomena  of  disease  as  they  are  manifested 
in  the  two  tissues.  Fibro-cartilage  appears  to 
be  susceptible  of  reparation  in  the  same  man- 
ner as  pure  cartilage.  (See  Cartilage.)  A 
substance  bearing  some  resemblance  to  fibro- 
cartilage  sometimes  forms  the  connecting  me- 
dium between  the  fractured  portions  of  a  bone, 
where  bony  union  cannot  be  obtained. 

The  phenomena  of  inflammation  and  ulce- 
ration in  fibro-cartilages  are  very  similar  to 

unfrequently  found.  Ossification  of  the  nasal 
cartilages  is  extremely  rave,  but  in  the  hog  tribe 
two  bones  extend  from  ihe  intermaxillary  bone  into 
the  cartilage  of  the  proboscis.  —  Vide  Miescher, 
)oc.  cit.  p,  27. 


those  in  pure  cartilage :  in  the  joints  these 
morbid  changes  are  generally  complicated  with 
similar  diseased  conditions  of  the  other  tex- 
tures, either  cartilages  or  bones,  whence  they 
are  propagated  to  the  fibro-cartilages.  It  is 
well  known  that  a  condition  of  the  interverte- 
bral discs,  which  is  commonly  spoken  of  under 
the  name  of  ulceration,  is  frequently  coin- 
cident with  caries  of  the  vertebrae,  having  in 
some  instances  preceded  the  vertebral  disease, 
and  in  others  followed  it.  To  Sir  Benjamin 
Brodie  we  are  indebted  for  the  observation  that 
the  diseased  state  of  the  intervertebral  substance 
has  sometimes  the  precedence  of  that  of  the 
bones ;  in  one  case,  related  by  him,  where 
ulceration  of  the  articular  cartilages  had  begun 
in  several  other  parts,  those  between  the  bodies 
of  some  of  the  dorsal  vertebrae  were  found  to 
have  been  very  much  altered  from  their  natural 
structure.  He  adds,  "  I  had  an  opportunity 
of  noticing  a  similar  morbid  condition  of  two 
of  the  intervertebral  cartilages  in  a  patient  who, 
some  time  after  having  received  a  blow  on  the 
loins,  was  affected  with  such  symptoms  as  in- 
duced Mr.  Keate  to  consider  this  case  as  one 
of  incipient  caries  of  the  spine,  and  to  treat  it, 
accordingly,  with  caustic  issues ;  and  who 
under  these  circumstances  died  of  another 
complaint.  Opportunities  of  examining  the 
morbid  appearances  in  this  very  early  stage  of 
disease  in  the  spine  are  of  very  rare  occur- 
rence, but  they  are  sufficiently  frequent  when 
the  disease  has  made  a  greater  progress;  and 
in  such  cases  I  have,  in  some  instances,  found 
the  intervertebral  cartilages  in  a  state  of  ulce- 
ration while  the  bones  were  either  in  a  perfectly 
healthy  state,  or  merely  affected  with  chronic 
inflammation,  without  having  lost  their  natural 
texture  and  hardness."*  Otto  mentions  that 
he  has  several  times  satisfied  himself  that  the 
destruction  of  the  spine  may  originally  spring 
from  the  intervertebral  substance;  but  he  has 
never  found  suppuration,  unless  when  at  the 
same  time  the  bones  and  neighbouring  cellular 
tissue  were  inflamed.+  The  anatomical  cha- 
racters of  this  condition  to  which  we  have 
been  alluding  consist  in  an  erosion  and  soften- 
ing of  the  fibro-cartilage,  frequently  attended 
with  the  effusion  on  the  surface  of  a  dirty 
puriform  and  often  fetid  fluid. 

Fibro-cartilage  is  not  prone  to  become  ossi- 
fied; in  very  old  subjects  the  superficial  portion 
of  the  intervertebral  substances  is  often  ossi- 
fied, but  this  is  an  extension  of  ossification 
from  the  bone  or  from  the  anterior  common 
ligament :  it  is  very  rare  to  find  any  of  the 
inter-articular  fibro-cartilages  ossified.  The 
ossification  of  the  interpubic  fibro-cartilage  in 
advanced  age  seems  to  be  of  a  similar  nature 
to  that  of  the  intervertebral  substances. 

Masses  of  a  substance  very  similar  to  fibro- 
cartilage  are  sometimes  met  with  accidentally 
developed  ;  we  find  them  in  or  connected  with 
the  uterus,  in  tumours,  and  in  serous  or  sy-» 
novial  membranes. 

(R.  B.  Todd.) 

*  Brodie  on  the  Joints,  edit.  2d,  p.  231, 
t  Pathol.  Anat.  by  South. 


FIBROUS  TISSUE. 


263' 


FIBROUS  TISSUE  *  tela  fibrosa,  vel  ten- 
dinea ;  Germ,  das  sehnige  Gewebe. 

The  parts  comprised  in  the  fibrous  system 
may  with  propriety  be  referred  to  two  separate 
and  distinct  classes. 

I.  White  fibrous  organs. — Under  this 
head  the  following  structures,  distinguished  by 
their  whitish  colour,  their  fibrous  organization, 
and  their  great  power  of  resistance,  are  in- 
cluded : — a,  the  periosteum  and  perichondrium  ; 
b,  fasciae  or  muscular  aponeuroses  ;  c,  sheaths  of 
the  tendons ;  d,  fibrous  coverings  of  certain 
organs  ;  e,  ligaments ;  j\  tendons. 

II.  Yellow  elastic  fibrous  organs. — 
There  are  certain  organs,  ex.  gr.  the  yellow 
ligaments  ( ligumenta  subflava )  of  the  spine, 
which  resemble  those  of  the  former  class  by 
their  fibrous  structure,  but  which  present  so 
many  important  peculiarities  in  their  texture 
and  properties,  that  it  is  necessary  to  consider 
them  apart  from  the  preceding.  All  these 
organs  resemble  each  other  by  possessing  more 
or  less  a  yellow  colour,  and  a  remarkable  de- 
gree of  elasticity. 

I.  White  fibrous  organs. —  Organiza- 
tion. This  consists  of  a  union  of  white 
or  grayish  fibres  more  or  less  distinct  accord- 
ing to  the  part  in  which  they  are  examined ; 
thus  they  are  very  apparent  in  most  of  the 
ligaments,  in  the  fascia,  in  the  periosteum,  and 
in  many  tendons,  as  in  those  of  the  obliquus 
abdominis  externus,  pectoralis  major,  &c.  In 
other  structures,  on  the  contrary,  as  in  the 
greater  number  of  tendons,  the  fibres  are  so 
small  and  so  closely  united  that  they  cannot  be 
perceived  but  with  difficulty,  although  they  be- 
come more  evident  on  maceration.  In  most 
parts  of  the  body  they  observe  a  parallel  direc- 
tion, whilst  in  other  places  they  pass  in  an  irre- 
gular manner,  so  as  to  cross  and  interlace  with 
each  other,  occasionally  constituting,  as  in  the 
instance  of  the  dura  mater  and  of  the  tendinous 
centre  of  the  diaphragm,  a  very  intricate  net- 
work of  fibres. 

The  result  of  a  careful  examination  proves 
that  the  remarkably  firm  and  resisting  threads 
which  constitute  the  basis  of  the  various  fibrous 
organs,  are  composed  of  condensed  cellular 
tissue.  In  certain  regions  we  may  perceive 
the  gradual  transformation  of  the  cellular  tissue 
into  a  fibrous  organ,  as  in  the  formation  of  the 
superficial  fascia  of  the  abdomen ;  whilst  by 
prolonged  maceration  the  most  dense  tendon 
or  ligament  may  be  reduced  into  a  pulpy  cellu- 
lar substance :  this  opinion  is  corroborated  by 
Isenflamm,  who  conceives  that  this  tissue  is 
formed  by  cellular  fibres  impregnated  with 
gluten  and  albumen  ;  and  also  by  Beclard,  who 
regards  it  as  being  composed  of  cellular  texture 
very  much  condensed.  We  may  therefore 
conclude  that  the  ideas  of  Professor  Chaussier, 

*  The  expression  fibrous  tissue  is  by  no  means 
well  chosen,  as  it  is  equally  applicable  to  other  and 
dissimilar  organs,  such  as  muscles,  nerves,  &c.  all 
of  which  are  eminently  distinguished  by  a  fibrous 
structure.  It  is,  however,  preferable  to  retain  a 
received  though  inaccurate  term,  than  to  add  to 
that  multitude  of  names  which  already  so  much 
encumbers  the  science  of  anatomy. 


as  to  the  existence  of  an  elementary  organic 
solid,  called  by  him  the  albugineous fibre,  and 
which  is  supposed  to  form  the  basis  of  all  the 
ligamentous  and  tendinous  parts  of  the  body, 
are  erroneous. 

The  individual  fibres  are  surrounded  by  pro- 
cesses of  a  more  lax  membrane,  which  pene- 
trates between  them,  and  which  is  rendered 
particularly  apparent  by  maceration  and  in  cer- 
tain diseases.  The  differences  that  are  observed 
in  contrasting  the  various  fibrous  organs  with 
each  other,  a  ligament  for  example  with  a  ten- 
don, seem  principally  to  result  from  the  larger 
or  smaller  proportion  of  the  interfibrous  cellu- 
lar substance  and  on  the  degree  of  its  conden- 
sation. This  combination  of  the  common  cel- 
lular tissue  with  the  ligamentous  fibres  allows 
the  fibrous  organs  to  yield  in  a  very  slight  de- 
gree when  extended  by  the  elasticity  which  is 
thus  bestowed,  and  also  slightly  to  contract  on 
themselves  on  the  removal  of  the  extending 
force. 

Bloodvessels. — The  proper  fibrous  tissue  re- 
ceives but  a  small  quantity  of  blood,  the  arteries 
being  minute  in  size,  and  principally  carrying 
a  colourless  fluid.  The  great  vascularity  of  the 
dura  m;iter  and  periosteum  is  no  exception 
to  this  remark,  because  the  vessels  of  these 
membranes  are  not  proper  to  them,  but  to  the 
veins  they  cover. 

Absorbents. — The  ravages  of  disease  in  the 
neighbourhood  of  joints,  involving  the  liga- 
ments in  ulceration  ;  the  sloughing  of  tendons, 
the  destruction  of  the  periosteum  by  the  pres- 
sure of  aneurism,  of  the  tunica  albuginea  in 
scrofulous  or  malignant  fungus  of  the  testis, 
are  abundant  proofs  of  the  existence  of  absor- 
bent vessels. 

Nerves. — According  to  Monro,  nervous  fila- 
ments may  be  traced  to  some  of  the  fibrous 
organs  ;  and  other  anatomists,  Cruveilhier  for 
instance,  speak  of  nerves  being  furnished  to 
the  joints;  in  general,  however,  none  are  to  be 
seen  ;  but  as  sensibility  becomes  developed  in 
disease,  we  must  presume  that  communications 
do  exist  with  the  encephalon. 

Chemical  properties.  —  The  principal  sub- 
stances that  have  been  detected  in  the  fibrous 
as  in  the  cellular  tissue  consist  of  coagulated 
albumen  and  gelatine ;  a  small  quantity  of 
mucus  and  saline  matter  has  also  been  disco- 
vered. The  effects  of  desiccation  are  well 
known,  tendons  and  ligaments  becoming  hard, 
transparent,  yellowish,  and  fragile.  This  tissue 
resists  maceration  for  a  long  time,  but  at  length 
it  is  rendered  soft  and  flocculent,  so  that  the 
fibres  can  be  separated  and  unravelled  ;  ulti- 
mately it  is  converted  into  a  pulpy  and  fila- 
mentous cellular  mass. 

Properties. — The  offices  which  these  organs 
are  designed  to  fulfil  in  the  economy  being, 
with  the  exception  of  the  periosteum  and  its 
analogous  membrane  the  dura  mater,  of  a  me- 
chanical character,  the  properties  by  which 
they  are  distinguished  are  almost  entirely  of  a 
physical  nature.  They  offer  great  resistance  to 
rupture,  and  thus  the  ligaments  are  capable  of 
opposing  the  shocks  to  which,  in  the  violent 
movements  of  the  joints,  they  are  so  frequently 


264 


FIBROUS  TISSUE. 


exposed ;  whilst  the  same  cohesive  property 
enables  the  tendons,  under  all  ordinary  circum- 
stances, to  bear  the  immense  force  of  muscular 
contraction. 

Having  considered  the  general  characters  of 
these  organs,  I  shall  proceed  to  describe  the 
most  essential  properties  of  each  individual 
class. 

1.  Of  the  periosteum. — This  may  be  regard- 
ed as  the  most  important  of  the  fibrous  tissues ; 
indeed  so  universal  are  its  connexions,  that  if 
any  common  centre  of  this  system  were  sought 
for,  we  should  certainly  coincide  with  Bichat 
in  considering  this  to  be  the  periosteum.  Dis- 
carding the  erroneous  ideas  of  the  ancients  and 
Arabian  physicians,  who  imagined  that  the 
membranes  of  the  body  were  all  continued 
from  those  of  the  head,  we  shall  find  that,  with 
the  exception  of  the  perichondrium  of  the  larynx 
and  the  fibrous  tunics  of  some  glandular  bodies, 
all  the  fibrous  organs  are  in  connexion  with  the 
periosteum. 

The  inner  surface  of  the  periosteum  firmly 
adheres  to  the  several  bones  by  a  multitude  of 
delicate  processes  passing  into  the  openings 
observed  on  their  external  surface.  These  pro- 
cesses convey  into  the  bones  an  amazing  num- 
ber of  fine  arteries  and  veins,  called  therefore 
periosteal,  and  which  may  be  regarded  as  the 
principal,  or  as  some  anatomists  contend,  the 
only  proper  vessels  of  the  osseous  tissue. 

The  outer  surface  is  rough,  and  is  united  by 
the  cellular  tissue  to  the  surrounding  muscles, 
tendons,  ligaments,  and  fascia? ;  in  the  nostrils, 
sinuses,  and  tympanum,  the  periosteum  is, 
however,  joined  to  the  mucous  membranes, 
and  in  the  skull  the  surface  unattached  to  the 
bones  is  lined  by  the  arachnoid. 

The  periosteum  constitutes  the  nutrient 
membrane  of  the  bones,  and  thus  bears  an  im- 
portant part  in  the  process  of  ossification  and 
in  the  reparation  of  fractured  and  diseased 
bones ;  it  also  serves  as  a  medium  for  the 
attachment  of  the  ligaments,  tendons,  and 
fascia?  to  the  skeleton. 

2.  Fascia. — The  fibrous  fasciae  or  aponeu- 
roses not  only  invest  the  surface  of  the  limbs, 
but  also  furnish  a  number  of  processes,  which, 
penetrating  deeply  among  the  several  muscles, 
form  sheaths  to  those  organs,  by  which  they  as 
well  as  the  bloodvessels  and  nerves  are  main- 
tained in  their  proper  situation.  It  is  evident 
that  these  partitions  must  exert  a  great  influence 
on  the  growth  of  various  kinds  of  tumours,  on 
effusion  of  blood,  on  the  extravasation  of  urine, 
and  on  the  formation  of  matter;  so  that  their 
relations  form  an  important  branch  of  surgical 
anatomy. 

In  order  to  give  to  these  muscular  envelopes 
the  necessary  degree  of  tension,  they  are  either 
provided  with  special  muscles,  as  in  the  case 
of  the  tensor  vagina?  femoris  and  the  palmaris 
longus,  or  they  receive  processes  from  the 
neighbouring  tendons,  as  from  the  biceps  cubiti, 
semi-tendinosus,  and  so  forth. 

The  aponeuroses  thus  braced  afford  a  firm 
support  to  the  parts  they  cover,  and  in  this 
manner  they  increase  the  powers  of  the  muscu- 
lar system ;   whilst  by  their  resistance  they 


efficiently  protect  the  vessels  and  nerves  from 
external  violence,  and  at  the  same  time  proba- 
bly assist  in  the  circulation  of  the  blood  and 
lymph,  and  so  prevent  varicose  enlargement  of 
the  deep-seated  veins  and  oedema  of  the  extre- 
mities.   See  Fascia. 

3.  Tendinous  sheaths.— These  are  in  their 
office  analogous  with  the  last,  excepting  that, 
instead  of  fixing  the  muscles,  they  secure  the 
tendons  during  muscular  action.  The  thecal 
ligaments  of  the  hand  and  foot,  the  annular 
ligaments  of  the  wrist  and  ankle,  and  the  fascial 
sheaths  around  the  knee  are  of  this  character. 
They  are  distinguished  by  their  great  strength, 
and  as  they  are  internally  lined  by  synovial 
membrane,  they  facilitate  the  play  of  the  ten- 
dons ;  and  in  many  instances,  as  in  the  trochlea 
of  the  os  frontis  and  the  sulci  of  the  carpal  extre- 
mity of  the  radius,  they  also  modify  the  action 
of  the  muscles  whose  tendons  they  transmit. 

4.  Fibrous  coverings.- — -Certain  organs  are 
provided,  for  the  purpose  of  protection,  with 
dense  ligamentous  coverings ;  of  this  order  are 
the  dura  mater,  the  sclerotic  coat  of  the  eye, 
the  loose  portion  of  the  pericardium,  the  proper 
covering  of  the  kidney,  of  the  salivary  glands, 
mamma,  spleen,  thyroid  gland,  thymus,  lym- 
phatic glands,  of  the  prostate,  testicle  and 
ovary  ;  probably  the  exterior  investment  of  the 
nervous  ganglia  is  of  the  same  character.  Some 
of  these  envelopes,  as  the  dura  mater,  pericar- 
dium, and  tunica  albuginea  testis,  are  lined  on 
one  surface  by  a  serous  membrane,  and  thus 
constitute  Jibro-serous  membranes,  or  as  they 
are  called  by  Beclard,  compound  fibrous  mem- 
branes. 

5.  Ligaments. — These  bodies  possess  in  an 
eminent  degree  those  properties  by  which  the 
whole  fibrous  system  is  distinguished ;  and 
consequently  the  term  ligamentous  is  often  em- 
ployed to  designate  the  whole  of  the  fibrous 
organs. 

The  ligaments  fulfil  a  very  important  office 
in  the  animal  economy  by  binding  together  the 
various  bones  of  the  skeleton,  an  object  which 
they  are  enabled  to  effect  in  consequence  of 
their  fibres  being  very  firmly  attached,  and  as 
it  were  consolidated  with  the  osseous  system 
through  the  medium  of  the  periosteum.  It  is 
stated  by  Portal,  that  after  the  bones  have  been 
softened  by  the  influence  of  an  acid,  the  liga- 
ments are  observed  to  send  processes  into  their 
substance,  which  cause  the  ligaments  to  adhere 
so  firmly  that,  although  by  very  great  force 
they  may  be  torn,  yet  they  cannot  be  separated 
from  the  bones. 

Although  these  organs  are  dissimilar  in 
shape,  yet  there  are  three  forms  among  them 
which  predominate:  t.  the  capsular,  2.  the 
funicular,  3.  what,  for  want  of  a  better  ex- 
pression, may  be  called  laminated.  The  true 
fibrous  capsules  which  consist  of  cylindrical 
bags  lined  internally  by  synovial  membrane, 
are  confined  to  the  shoulder  and  hip-joints, 
although  imperfect  capsules  exist  in  many 
other  articulations.  The  funicular  and  la- 
minated ligaments  are  much  more  universally 
diffused,  assisting  in  fact  in  the  formation  of 
every  joint  in  the  skeleton. 


FIBROUS  TISSUE. 


6.  Tendons. — These  organs,  which  serve  to 
connect  the  muscles  to  the  osseous  system, 
are  composed  of  fibres  so  closely  disposed 
that  some  anatomists,  but  erroneously,  doubt 
their  identity  with  the  other  fibrous  organs. 
This  compactness  is  owing  to  the  extreme  con- 
densation of  the  intervening  cellular  tissue, 
which  is  also  the  cause  of  these  bodies  re- 
sisting for  a  longer  period  than  the  ligamen- 
tous or  fascial  structures,  the  influence  of  ma- 
ceration. 

Every  tendon  is  united  by  one  of  its  ex- 
tremities to  the  fibres  of  the  muscle  to  which 
it  belongs,  and  by  the  other  it  is  connected 
with  the  bone  or  other  part  on  which  the 
muscle  is  destined  to  act.  The  exact  mode 
of  connexion  between  the  tendinous  and  mus- 
cular tissues  is  difficult  to  determine.  Ocular 
and  microscopical  inspection  seem  to  prove 
that  the  tendinous  fibres  result  from  the  con- 
tinuation and  condensation  of  those  cellular 
sheaths,  which  inclose  and  in  part  form  the 
muscular  fibrils.  It  has,  however,  been  stated 
that  there  is  an  intermediate  substance  between 
the  muscle  and  the  tendon,  different  from 
both  of  them,  and  serving  to  connect  them 
together.  The  details  relative  to  the  mecha- 
nical disposition  of  these  organs  belong  to  the 
consideration  of  the  muscular  system. —  See 
Muscle. 

II.  Yellow  elastic  fibrous  organs. — 
(Tela  elastica.)  It  was  justly  observed  by 
Bichat  that  the  ligaments  placed  between  the 
arches  of  the  vertebrae  differ  in  their  nature 
from  the  other  ligaments  of  the  body;  and 
modern  anatomists,  admitting  this  distinction, 
have  enumerated  the  following  structures  as  a 
separate  class  of  the  fibrous  organs  :  the  yellow 
ligaments  of  the  spine ;  the  external  and  espe- 
cially the  middle  or  proper  membrane  of  the 
arteries,  the  fibrous  covering  of  the  excretory 
ducts;  the  ligamentous  tissue  joining  the  carti- 
lages of  the  air-passages;  the  fibrous  envelope 
of  the  cavernous  bodies  of  the  penis  and  clitoris, 
and  of  the  vesiculas  seminales. 

Although  the  highest  authorities  consider 
that  the  middle  tunic  of  the  arteries  is  com- 
posed of  this  tissue,  yet  the  correctness  of  this 
opinion  is  very  doubtful.  It  is  true  that,  as 
far  as  colour  is  concerned,  the  similarity  is 
well  founded  ;  but  the  arterial  fibrous  coat  is 
endowed  with  a  power  of  contraction,  evi- 
dently distinct  from  mere  elastic  contraction, 
which  is  totally  wanting  in  the  true  yellow 
fibrous  tissue. 

In  addition  to  the  parts  above  named,  it  is 
necessary  to  add  that  in  certain  organs  where 
great  elasticity  is  requisite  there  is  a  peculiar 
yellow  cellular  substance,  which,  although  it 
does  not  present  the  dense  and  fibrous  cha- 
racter, appears  to  belong  essentially  to  the 
organs  under  consideration.  This  texture  is 
particularly  distinct  in  the  mucous  folds 
which  constitute  the  superior  boundary  of  the 
glottis,  a  part  that  is  remarkable  for  its  extra- 
ordinary elasticity.* 

*  It  is  slated  by  Sir  E.  Home  (Lett,  on  Comp. 
Anat.  vol.  ii.  p.  49,)  that  this  tissue  enters  into  the 


It  occasionally  happens,  as  in  the  forma- 
tion of  the  intervertebral  substance,  that  the 
yellow  fibrous  tissue  and  the  common  liga- 
mentous are  combined.  A  more  striking 
instance  of  this  combination  is  seen  in  the 
construction  of  the  connecting  ligament  which 
forms  the  hinge  in  bivalve  shells,  in  which  one 
part,  the  external,  is  composed  of  ligamentous 
matter,  whilst  another,  the  internal,  consists 
of  a  highly  elastic  fibrous  tissue. 

Organization  and  properties. — If  the  yellow 
ligament  of  the  spine  or  the  ligamentum  nu- 
chas in  ruminants  be  examined,  it  will  be  seen 
that  each  is  smooth  on  its  surface,  and  is  made 
up  of  a  great  number  of  longitudinal  and 
highly  elastic  fibres,  which,  in  the  latter  in- 
stance, are  readily  separated  and  unravelled 
by  the  finger.  This  texture  is,  I  believe,  sui 
generis,  and  is  altogether  distinct  from  the 
common  ligamentous  structures.  In  a  recent 
publication,*  M.  Laurent  conceives  that  this 
tissue  is  intermediate  in  its  characters  to  the 
tissus  scltreux  (under  which  term  he  proposes 
to  class  the  white  fibrous  organs,  the  cartilages 
and  bones,)  and  the  muscular  tissue ;  he  there- 
fore calls  it  tissu  sclero-sarceux.  Although  it 
is  very  doubtful  if  the  elastic  fibrous  structures 
have  any  thing  in  their  organization  similar  to 
the  muscular  fibre,  yet  it  is  certain  that  in 
function  they  are  intermediate  between  the 
common  ligaments  and  the  muscles,  a  fact 
which  is  kept  in  view  in  thellunterian  Museum, 
in  which  the  elastic  ligaments  are  placed  next  to 
the  muscles. 

The  resistance  and  elasticity  of  these  organs 
enable  them  firmly  to  connect  together  the 
parts  to  which  they  are  attached,  and  at  the 
same  time  allow  them  to  yield  to  double  their 
length  on  the  application  of  an  extending 
force.  In  this  manner  they  economise  mus- 
cular action,  by  substituting  for  that  force  the 
power  of  elasticity. 

This  employment  of  an  elastic  rather  than 
a  muscular  power  is  evinced  in  the  yellow 
ligaments  of  the  spine,  which  pull  the  vertebras 
towards  each  other,  and  thus  assist  the  muscles 
in  maintaining  the  upright  posture.  The  same 
thing  is  also  seen  in  many  of  the  lower  ani- 
mals ;  as  in  the  support  of  the  head  by  the 
ligamentum  nuchas — the  retraction  of  the  claws 
in  the  feline  carnivora  by  an  elastic  ligament — 
and  the  support  of  the  abdominal  organs  in 
many  large  quadrupeds  by  the  elastic  super- 
ficial fascia.  But  the  most  interesting  ex- 
ample of  this  economy  of  muscular  action 
is  displayed  in  the  bivalve  shell  of  the  oyster 
and  other  acephalous  mollusca,  in  which  in- 
stance not  only  is  the  shell  kept  open  by  the 
elastic  ligament  of  the  hinge  for  the  purpose 
of  admitting  the  nutriment  of  the  animal ;  but 

formation  of  muscle  ;  but  this  is  probably  erro- 
neous, as  the  elasticity  of  muscles  depends  on  the 
large  proportion  of  elastic  cellular  membrane  w  hich 
they  contain.  Lobstein  has  also  published  some 
observations  in  the  Jour.  Univer.  des  Sc.  Med.  on 
the  tissue  of  the  uterus,  which  he  regards  as  ana- 
logous to  the  so-called  yellow  tissue  of  the  middle 
arterial  coat. 

*  Annales  Franchises  el  Eu-angcres  d'Anal.  et  dc 
Physiol.  Jan.  1837.    I*.  59. 


266 


FIBROUS  TISSUE. 


as  the  valves  are  designed  by  nature  to  be 
separated  only  to  a  limited  extent,  an  elastic 
ligamentous  structure  is  placed  between  them 
towards  their  centre,  and  in  this  manner  all 
undue  separation  is  prevented  without  any 
demand  being  made  on  the  force  of  the  ad- 
ductor muscle.* 

Morbid  anatomy.  I.  Inflammation. — 
The  low  degree  of  organization  possessed  by 
this  tissue  modifies  the  inflammatory  process, 
which  is  usually  chronic  in  its  nature,  and 
often  extremely  insidious  in  its  progress ;  occa- 
sionally, however,  as  in  sprains,  acute  rheu- 
matism, &c,  the  fibrous  organs  are  the  seat 
of  very  active  disease.  Owing  to  their  great 
density,  but  little  swelling  takes  place  unless 
there  be  chronic  and  prolonged  inflammation  ; 
in  which  case,  as  is  particularly  observed  in 
disease  of  the  joints,  a  quantity  of  jelly-like 
fluid  is  poured  into  the  interstitial  cellular 
tissue,  the  proper  fibres  become  massed  toge- 
ther and  with  the  surrounding  parts,  till  in  the 
advanced  stage  all  traces  of  the  original  for- 
mation being  lost  in  the  diseased  mass,  it  be- 
comes reduced  to  the  pulpy  consistence  of 
diseased  cellular  membrane,  of  which  the 
healthy  structure  is  a  modification. 

This  deposit  and  thickening  are  the  most 
common  products  of  inflammation  in  liga- 
mentous parts ;  but  it  occasionally  happens 
that  a  true  abscess  is  formed,  as  when  pus  is 
thrown  out  between  the  dura  mater  and  cra- 
nium. I  have  known  one  case  connected  with 
disease  of  the  bone,  in  which  matter  was  de- 
posited in  the  substance  of  the  dura  mater, 
and  in  which  the  operation  of  trephining  was 
ultimately  required  for  the  relief  of  the  patient. 

Ulceration  is  a  frequent  result  of  scrophu- 
lous  disease  of  the  joints,  causing  great  ravages 
in  the  ligaments  and  neighbouring  parts. 

Mortification  of  ligament  is  not  a  common 
occurrence,  whilst  in  the  acute  inflammation 
of  tendon,  especially  in  neglected  thecal  ab- 
scess, and  of  fascia  in  consequence  of  large 
abscess  under  it,  sloughing  is  not  unfrequently 
witnessed. 

There  are  of  course  certain  modifications  in 
the  effects  of  inflammation  according  to  the 
part  attacked.  Thus,  in  ligament,  there  is  a 
great  tendency  to  ulceration ;  in  tendon  to 
mortification ;  in  the  periosteum  to  great  in- 
duration ;  and,  as  we  see  in  the  formation  of  a 
node  and  of  callus,  to  a  transformation  into 
cartilage  and  even  bone.  When  fascia  is  the 
seat  of  disease,  the  consolidation  arising  from 
effusion  often  gives  rise  to  a  retraction  of  the 
affected  part;  a  result  which  has  been  observed, 
for  example,  in  inflammation  of  the  aponeu- 

*  Leach,  Bullet,  des  Sciences,  1818.  P.  14. 
[Mr.  Hunter  fully  recognised  the  value  of  this 
elastic  tissue,  and  in  his  Museum  he  set  apart  a 
series  for  its  illustration  under  two  classes — 1st,  as 
an  antagonist  to  muscle,  and  2d,  in  aid  of  mus- 
cular action.  In  the  former  class  he  places  such 
examples  as  that  of  the  oyster  alluded  to  in  the 
text,  in  the  latter  the  ligamenta  nuchae  and  the 
elastic  fibrous  expansion  on  the  abdomen  of  the 
elephant  and  other  larger  quadrupeds.  See  the 
Descriptive  and  Illustrated  Catalogue  of  the  Hun- 
terian  Museum,  vol.  i. — Ed.] 


rosis  of  the  fore-arm,  and  in  that  affection  of 
the  palmar  fascia  called  by  Boyer  and  other 
writers  crispatura  tendinum* 

II.  Cartilaginous  transformation  and  ossi- 
fication.— Many  parts  of  the  fibrous  system 
not  unfrequently  become  cartilaginous  or  even 
osseous.  The  cartilaginous  transformation  is 
often  observed  in  the  ligaments  of  diseased 
and  anchylosed  joints;  in  the  periosteum  after 
fractures  and  in  the  formation  of  nodes ;  in 
tendons,  especially  those  which  are  exposed  to 
great  friction  in  the  fibrous  covering  of  the 
spleen.  I  have  had  opportunities  of  seeing 
many  specimens  of  cartilaginous  deposit  taking 
place  between  the  periosteum  and  the  bone, 
and  evidently  arising  from  the  former.  The 
valuable  collection  of  my  friend  Mr.  Listen 
contains  a  very  fine  specimen  of  a  large  carti- 
laginous tumour  proceeding  from  the  peri- 
osteum. 

Ossification,  although  extremely  common, 
occurs  much  more  frequently  in  some  than  in 
other  classes  of  these  organs :  thus  it  is  often 
met  with  in  the  dura  mater,  in  which  structure, 
as  far  as  I  have  observed,  the  bony  excres- 
cence always  proceeds  from  the  inner  layer  or 
that  towards  the  arachnoid,  and  consequently 
presses  against  the  brain.  In  one  very  re- 
markable specimen  in  my  possession,  nearly 
the  whole  of  the  falx,  and  a  large  extent  of  the 
membrane  attached  to  the  vault  of  the  cranium, 
are  completely  ossified.  In  an  instance,  ob- 
served I  believe  by  Dr.  Barlow  (Southwark), 
the  heart  was  completely  encased  in  bone, 
owing  to  the  entire  ossification  of  the  peri- 
cardium. The  cicatrix  of  a  wounded  tendon 
is  often  osseous. 

III.  Fungus. — The  dura  mater,  the  peri- 
osteum, the  fascia,  &c,  are  subject  to  excres- 
cences having  a  fungoid  appearance,  which 
vary  in  their  nature,  often  consisting  of  a 
chronic,  indolent  growth,  whilst  at  other  times 
they  are  evidently  scrophulous,  and  occasion- 
ally they  are  malignant. 

In  the  progress  of  those  cases  where  the 
disease  is  situated  near  the  bones,  these  organs 
are  implicated,  and  some  doubt  has  conse- 
quently arisen  concerning  the  first  seat  of  the 
disease  ;  it  is,  however,  proved  by  examination 
that  in  the  fungus  of  the  dura  mater  and  other 
fibrous  parts,  the  bones  are  only  secondarily 
affected.  A  good  illustration  of  this  fact  is 
afforded  by  a  preparation  consisting  of  an 
extensive  fungus  arising  from  the  periosteum 
covering  the  tibia,  in  which  it  is  evident,  al- 

*  Boyer,  Traite  des  Malad.  Chir.  torn.  v.  p.  55. 
This  peculiar  affection  was  some  years  since  pointed 
out  by  Sir  A.  Cooper,  and  has  since  been  more  fully 
described  by  Baron  Dupuytren,  (Lecons  Orales  de 
Chir.  Clin.  torn.  i.  p.  2).  The  tension  and  contrac- 
tion of  the  palmar  fascia,  which  are  usually  caused 
by  continued  pressure,  give  rise  to  aretraction  of  one 
or  more  of  the  fingers,  and  may  be  removed  by 
transversely  and  freely  dividing  the  aponeurosis 
opposite  to  the  metacarpo  phalangean  joint.  I 
have  known  one  case  of  similar  induration  of  the 
fibrous  sheath  of  the  corpus  cavcrnosum  penis ; 
and  I  have  learnt  from  Sir  A.  Cooper  that  he  has 
seen  several  such  cases,  occurring  in  persons  who 
had  freely  indulged  in  sexual  intercourse.  Boyer 
has  made  a  similar  observation. 


FIBULAR  ARTERY. 


267 


though  the  subjacent  bone  has  been  partly 
absorbed,  that  the  fungoid  disease  entirely 
originated  from  the  periosteum* 

Malignant  fungus  occasionally  arises  from 
the  periosteum.  I  have  seen  one  case  of  this 
disease  connected  with  the  tibia,  in  which 
amputation  was  performed,  but  with  an  un- 
favourable result,  the  patient  sinking  rapidly 
from  mortification.  In  medullary  sarcoma 
that  membrane  is  often  involved. 

Osteo  -  sarcoma,  according  to  Ilowship, 
Craigie,  and  Meckel,  occasionally  has  its  ori- 
gin in  the  periosteum. 

( R.  D.  Grainger. ) 

FIBULAR  ARTERY,  (art'eria  peronaa ; 
Fr.  artire  peroniere ;  Germ,  die  Wudenbein- 
urterie ). — This  artery  is  commonly  described 
as  a  branch  of  the  posterior  tibial,  or  it  may 
be  said  to  be  one  of  the  branches  resulting 
from  the  bifurcation  of  a  short  trunk  which  has 
its  origin  immediately  from  the  popliteal,  and 
which  has  been  described  under  the  name  of 
the  tibio-peroneal  artery,  the  other  branch  of  the 
bifurcation  being  what  is  ordinarily  considered 
as  the  continued  posterior  tibial  trunk. 

The  origin  of  the  fibular  artery  is  situated 
about  an  inch  below  the  inferior  margin  of  the 
popliteus  muscle,  thence  the  artery  extends 
downwards  and  with  a  very  gradual  inclination 
outwards,  and  terminates  in  the  region  of  the 
external  ankle,  just  above  the  os  calcis  and 
behind  the  fibula.  It  is  a  vessel  of  smaller 
size  than  the  posterior  tibial,  and  about  equal  to 
the  anterior  tibial,  and  it  is  interesting  to  ob- 
serve that  the  varieties  in  its  calibre  are  in  the 
inverse  ratio  of  the  calibre  of  the  anterior  and 
posterior  tibial,  but  more  especially  of  the 
former. 

To  expose  the  fibular  artery  in  dissection  the 
gastrocnemius  and  soleus  muscles  must  be 
raised,  and  the  deep  fascia  of  the  leg  dissected 
away.  The  artery  is  then  seen  resting  at  first 
for  a  very  short  distance  upon  the  tibialis  posti- 
cus muscle,  and  from  it  getting  upon  the  pos- 
terior surface  of  the  fibula  near  its  tibial  edge, 
where  the  vessel  is  imbedded  in  the  flexor  pol- 
licis  proprius  and  encased  between  that  muscle 
and  the  bone.  Inferiorly  it  passes  between  the 
flexor  pollicis  proprius  and  tibialis  posticus, 
and  is  applied  to  the  posterior  surface  of  the 
interosseous  ligament. 

The  fibular  artery  is  sometimes  altogether 
absent,  and  then  its  place  is  supplied  by  rami- 
fications of  the  posterior  tibial.  Sometimes 
the  fibular  artery  takes  its  rise  higher  up  than  the 
point  we  have  indicated  ;  but  more  frequently 
it  has  a  lower  origin,  in  which  case  it  presents 
a  calibre  smaller  than  that  which  may  be  con- 
sidered as  usual ;  the  vessel,  indeed,  is  found  to 
be  smaller  the  lower  down  its  origin  is.  It  is 
in  these  cases  that  the  anterior  tibial  especially 
and  the  posterior  tibial  occur  of  a  larger  size  than 

The  result  of  dissection  induces  me  to  suppose 
that  in  many  old  and  intractable  ulceis,  the  fun- 
goid excrescences  seen  on  the  surface  arise  either 
from  the  fascia  of  the  leg  or  from  the  periosteum, 
according  as  they  are  placed  on  the  outer  or  inner 
part  of  the  limb. 


natural,  as  it  were  to  compensate  for  the  de- 
ficiency of  the  fibular. 

Branches.- — The  first  branches  the  fibular 
artery  gives  off  are  small  muscular  ones  on 
either  side  to  the  soleus,  tibialis  posticus,  flexor 
pollicis  proprius,  to  which  in  its  whole  course 
it  gives  a  liberal  supply;  also  to  the  fibula  and 
the  peroncei  muscles.  From  its  inner  side, 
according  to  Cruveilhier,  it  gives  an  anasto- 
motic branch  to  the  posterior  tibial,  which 
passes  transversely  or  obliquely  from  one  artery 
to  the  other.  This  branch  sometimes  attains  a 
considerable  size,  and  in  such  cases  after  its 
communication  with  the  posterior  tibial,  that 
artery  also  becomes  considerably  enlarged. 

The  fibular  artery  divides  into  its  two  termi- 
nal arteries  in  the  inferior  third  of  the  leg; 
these  are  the  anterior  and  posterior  peroneal 
arteries. 

Anterior  peroneal  artery,  (urteria  peronaa 
anterior  and  perjorans  peronaa.)  This  branch 
gains  the  anterior  surface  of  the  leg  by  piercing 
the  interosseous  ligament,  where  it  is  covered 
by  the  peronaeus  tertius  muscle.  The  situation 
at  which  this  perforation  takes  place  is  stated 
by  Harrison  to  be  about  two  inches  above  the 
external  ankle;  it  then  inclines  downwards 
upon  the  outer  side  of  the  tibia,  anastomoses 
by  a  transverse  branch  with  the  anti-tibial,  com- 
municates with  the  external  malleolar  artery 
from  the  anterior  tibial,  giving  off  numerous 
branches  both  before  and  after  the  anastomosis, 
which  pass  down  to  the  tarsus  and  communi- 
cate with  the  tarsal  arteries.  This  artery  is 
generally  smaller  than  the  posterior,  some- 
times so  small  that  the  ordinary  injection  fails 
to  penetrate  it.  If  there  be  any  anomaly  in  the 
size  of  the  anterior  tibial  artery,  this  branch  is 
generally  large  in  proportion  as  that  artery  is 
small,  and  in  such  a  case  it  might  exceed  the 
posterior  peroneal  in  calibre.  The  arteries  of 
the  dorsum  of  the  foot  spring  from  the  anterior 
peroneal  when  the  anterior  tibial  exhibits  this 
deficiency. 

Posterior  peroneal  artery,  {A.  peronaa  pos- 
terior ;  calcanienne  externe,  Cruveilhier).  This 
branch  continues  the  course  of  the  fibular  artery 
behind  the  external  malleolus  to  the  outer  side 
of  the  os  calcis;  it  runs  parallel  to  the  outer  edge 
of  the  tendo  Achillis,  being  immediately  covered 
by  the  continuation  of  the  fascia  of  the  leg. 
A  transverse  branch  from  the  inner  side  of  this 
artery  establishes  its  communication  with  the 
posterior  tibial,  and  inferiorly  it  distributes  its 
terminal  branches  to  the  muscles  and  other 
parts  on  the  outside  of  the  os  calcis  to  anasto- 
mose with  the  external  tarsal  and  plantar 
arteries;  some  small  vessels  proceed  round  the 
tendo  Achillis  to  effect  a  further  communication 
with  the  posterior  tibial. 

This  may  be  considered  as  the  terminal 
branch  of  the  fibular  artery ;  it  is  absent  only 
when  the  fibular  artery  passes  entirely  forwards, 
or  vi  hen  it  directly  opens  into  the  posterior 
tibial  without  having  any  further  communica- 
tion with  the  arteries  of  the  ankle. 

The  fibular  artery  is  evidently  a  valuable 
anastomotic  trunk  to  both  the  tibial  arteries,  a 
deficiency  in  either  of  which  it  is  prepared  to 


268 


FIFTH  PAIR  OF  NERVES. 


supply.  Deriving  its  origin  from  the  same 
source,  and  anastomosing  freely  with  both  in 
all  parts  of  their  respective  courses,  it  is  pre- 
pared to  take  the  place  of  either,  one  might  say, 
at  a  moment's  warning,  and  the  freedom  of 
this  communication  affords  a  sufficient  indica- 
tion to  surgeons  how  ineffectual  in  cases  of 
wounds  a  single  ligature  would  be;  in  short, 
here  as  in  other  places  where  arterial  communi- 
cations are  so  free,  the  rule  of  practice  is  so 
clearly  pointed  out  by  the  anatomy  as  almost 
to  render  it  superfluous  to  appeal  to  experience. 

The  relations  of  this  artery  to  operations  being 
very  similar  to  those  of  the  posterior  tibial,  we 
refer  on  this  head  to  the  article  Tibial  Ar- 
teries. 

(R.  B.  Todd.) 

FIFTH  PAIR  OF  NERVES.— This  title 
is  derived  from  the  relation  which  the  nerve 
bears  numerically  to  the  other  encephalic  pairs; 
it  is  the  fifth  nerve  met  with  on  the  base  of  the 
brain  counting  from  before  backwards.  The 
fifth  is  also  called  the  trigeminal  (Winslow) 
and  the  trifacial  (Chaussier)  nerve.  It  is  the 
nerve  upon  which  the  general  and  tactile  sensi- 
bility of  the  face  and  its  cavities,  as  well  as  the 
voluntary  power  of  certain  muscles  of  these 
parts,  depends. 

The  following  account  of  this  nerve  is  meant 
to  apply  especially  to  the  human  subject;  but 
as  a  knowledge  of  its  structure  and  distribution 
in  other  animals  must  contribute  very  much  to 
enlighten  us  in  regard  to  its  true  character  and 
properties  in  man,  occasion  has  been  taken  to 
mention  those  particulars  by  which  it  is  dis- 
tinguished throughout  the  animal  series. 

The  fifth  nerve  is  connected  at  its  one  ex- 
tremity with  the  medulla  oblongata,  whilst 
its  other  end  is  distributed  to  the  eye  and  its 
appendages,  to  the  nostrils,  to  the  palate,  the 
mouth  and  tongue,  to  the  salivary  glands,  to 
the  ear,  to  the  integuments  and  muscles  of 
the  face,  forehead,  and  temple,  and  to  the 
muscles  which  move  the  lower  jaw  in  mas- 
tication, the  temporal,  pterygoid,  and  mas- 
seter  muscles.  The  general  distribution  of  the 
nerve  throughout  the  animal  series  corres- 
ponds to  that  in  man  ;  but,  in  certain  animals 
and  classes,  varieties  are  presented,  which 
claim  our  attention  equally,  whether  as  matters 
of  curiosity  or  of  physiological  interest.  In 
some  individuals  of  the  class  Mammalia,  the 
eyes  possess  a  very  inferior  degree  of  develop- 
ment; a  distinct  optic  nerve  either  does  not 
exist  or  its  existence  is  a  matter  of  doubt, 
and  its  place  is  supplied,  in  part  or  alto- 
gether, by  a  branch  of  the  second  division 
of  the  fifth  nerve:  thus,  in  the  Mole,  accord- 
ing to  M.  Serres,*  the  optic  is  altogether 
absent,  and  its  place  is  supplied  by  a  branch 
of  the  fifth  ;  but,  according  to  Treviranus,f 
that  animal  is  provided  with  an  optic  nerve, 
as  large  as  a  human  hair,  and  according  to 
CarusJ  it  joins  an  optic  branch  from  the  fifth, 
and  the  two  concur  to  form  the  retina.  In 

*  Anatomie  Comparce  du  Cerveau,  &c. 
t  Journal  Complementaire. 
|  Journal  Compl. 


other  animals  of  the  same  class  the  optic  seems 
decidedly  absent,  and  its  place  is  supplied  al- 
together by  the  fifth.  Among  Reptiles  also  in- 
stances occur,  in  which  the  optic  nerve  is 
wanting.  According  to  both  Tie viranus*  and 
Serres,  f  the  fifth  nerve  takes  the  place  of 
the  optic  in  the  Proteus  Anguinus.  A  va- 
riety in  distribution,  still  more  remarkable, 
is  presented  in  the  disposition  of  the  fifth 
nerve  in  Fishes.  Among  the  Rays  the  audi- 
tory appears  to  be,  not  a  distinct  nerve,  but 
a  branch  of  the  fifth :  J  the  special  organs, 
with  which  they  are  provided,  likewise,  in 
many  instances,  derive  their  nerves  from  the 
fifth  pair;  thus,  in  some  the  electrical  §  organs 
are  supplied  by  that  nerve,  and  also  the  albu- 
mino-gelatinous  organs :  lastly,  in  many  the 
nerve  is  distributed  ||  in  a  manner  and  to  an 
extent  for  which  there  is  no  analogy  among 
other  animals,  the  fins  being  throughout  fur- 
nished with  branches  from  the  fifth.  Hence 
in  Fish,  in  which  the  distribution  of  the 
nerve  is  so  much  more  extended  than  in 
other  animals,  both  the  size  of  it  is  propor- 
tionally greater,  and  it  consists  of  a  greater^ 
number  of  divisions  ;  these,  which  in  the  three 
other  classes  of  vertebrate  animals  are  only 
three,  amounting  with  them  to  from  three  to 
six.  See  sketch  of  nerves  in  the  Ray  and  Cod. 
(Figs.  144,  145.) 

The  size  of  the  fifth  nerve  is  very  great,  it 
being  by  far  the  largest  of  those  proceeding  from 
the  medulla  oblongata.  In  this  respect  it  pre- 
sents much  variety  according  to  the  animal  or  its 
class.  M.  Serres  states  that,  the  nerves  being 
proportioned  always  to  the  volume  of  the 
organs  from  whence  they  proceed,  the  extent 
of  the  face  and  of  the  organs  of  the  senses 
taken  together  gives  the  size  of  this  nerve  in 
the  different  classes  of  vertebrate  animals. 
Among  the  Mammalia  the  extent  of  the  face 
and  of  the  organs  of  the  senses  increases  pro- 
gressively from  Man  to  Apes,  the  Carnivora, 
the  Ruminantia,  and  the  Rodentia,  and,  ac- 
cording to  him,  the  size  of  the  fifth  nerves 
follows  in  a  general  manner  the  same  pro- 
gression. Birds  are  remarkable  for  the  atrophy 
of  the  muscles  of  the  face  and  of  several  of 
the  organs  of  the  senses,  and  their  fifth  nerve 
is  far  from  presenting  the  developement  to  be 
observed  in  the  inferior  Mammalia.  Reptiles 
are  still  lower  than  Birds  with  regard  to  the 
dimensions  of  the  nerves  of  the  fifth  pair; 
while  in  Fish**  the  size  of  the  nerve  is  very 
great,  and  even  surpasses  in  some  the  volume 
it  presents  in  the  other  classes.ft  However  just 
the  estimate  of  the  comparative  volume  of  the 
nerve  in  different  animals,  as  here  stated,  may 

*  Op.  cit. 
t  Op.  cit. 

j  Dusmoulins,  Journal  de  Physiologie,  t.  li. 
Serres,  op.  cit. 

§  Desmoulins,  Anatomie  des  Systemes  Nerveux, 
&c.  Carus,  Rudolphi. 

||  Desmoulins,  op.  cit. 

If  Desmoulins,  op.  cit. 

**  See  Sketches  of  Nerve  in  the  Ray  and  Cod, 
Jigs.  144,  145. 

'  ft  Serres,  Anatomic  Comparce  du  Cerveau, 
dans  les  quatre  classes  des  Animaux.  Vertebres. 


FIFTH  PAIR  OF  NERVES. 


209 


be,  the  data,  from  which  it  is  professedly 
drawn,  may  be  reasonably  objected  to.  In 
the  first  place  the  volume  of  the  organ  cannot 
be  assumed  as  being  alone  the  measure  of  that 
of  the  nerve  supplying  it  •  the  degree  of  ner- 
vous endowment,  whether  general  or  special, 
which  the  organ  enjoys,  must  be  also  taken 
into  account ;  and  in  the  second,  the  extent 
of  the  organs  of  the  senses  cannot  be  admitted 
as  a  measure  of  the  volume  of  the  fifth  nerve, 
which  is  not  connected  with  them  all ;  thus 
the  greater  part  of  the  organs  of  touch  is  inde- 
pendent of  that  nerve.  It  appears  to  me 
that  the  extent  of  distribution  and  amount  of 
endowment  conjointly  determine  the  volume 
of  the  nerve,  and  that  the  latter  cannot  be 
inferred  a  priori. 

Each  nerve  is  composed  of  two  portions, 
which  are  remarkable  for  particular  characters, 
and  have  received  distinct  names;  they  differ 
from  each  other  in  size,  in  anatomical  disposi- 
tion, and  in  function  ;  one  of  them,  larger  than 
the  other,  is  provided  with  a  ganglion,  and  dif- 
fers in  its  distribution  ;  it  also  differs  in  proper- 
ties, being  subservient  to  sensation  ;  the  other 
is  small,  has  no  ganglion,  and  is  destined  to 
volition ;  they  are  hence  denominated,  the 
former  the  larger,  the  ganglionic  or  the  sentient 
portion,  the  latter  the  smaller,  the  non-ganglio- 
nic  or  the  voluntary  portion. 

The  distinction  of  the  nerve  into  two  por- 
tions appears  to  prevail  uniformly  throughout 
the  animal  series.  According  to  M.  Serres,  it 
is  to  be  observed  in  all  the  classes  of  the  ver- 
tebrate animals  except  the  Reptiles ;  but  in 
them,  according  to  him,  the  lateral  fasciculi  * 
are  wanting.  The  latter  assertion,  however,  is 
incorrect,  the  distinction  being  to  be  observed 
as  satisfactorily  in  that  class  as  in  any  other.f 
Again,  the  distinction  is  not  equally  remarkable 
in  all ;  in  some  it  is  still  more  so  than  in  man  ; 
in  others  it  is  less;  and  according  to  the  same 
authority,  it  is  to  be  observed  among  Mam- 
malia the  more  easily  as  we  pass  from  Man  to 
the  Rodentia.  Among  the  Cetacea  it  is  divi- 
ded throughout  into  two  separate  fasciculi.}; 

Each  of  the  two  portions  of  which  the  nerve 
consists  is  a  packet  containing  numerous  fas- 
ciculi, which  are  again  divisible  into  filaments. 
The  fasciculi,  of  which  the  packets  are  com- 
posed, are  differently  circumstanced  in  different 
stages  of  the  course  of  the  nerve ;  in  one  part 
they  are  bound  up  so  closely  together  that  they 
cannot  without  difficulty  be  separated  from  each 
other  and  disentangled,  while  in  another  they 
are  but  loosely  connected  and  are  easily  sepa- 
rated. 

The  two  packets  are  associated  together  more 
or  less  intimately  throughout  their  course  ;  but 
inasmuch  as  they  present  remarkable  varieties 
in  their  disposition  and  mutual  relations  at  dif- 
ferent parts,  it  may  be  advantageous  to  divide 
the  nerve,  through  its  course,  into  three  por- 
tions or  stages;  one  from  the  ganglion  to  the 
connexion  of  the  nerve  with  the  brain,  which 

*  The  name  by  which  he  designates  the  lesser 
portion  of  the  nerve, 

t  See  sketch  of  fifth  nerve  in  the  Turtle,/,?.  143. 
t  Op.  cit. 


may  be  denominated  its  internal  or  encephalic 
portion;  a  second  from  the  ganglion  to  its  ulti- 
mate distribution,  its  external  or  peripheric 
portion  ;  and,  thirdly,  its  ganglion.  Such  a 
distinction  may  not  be  free  from  objection,  but 
being  adopted  for  the  convenience  of  descrip- 
tion, it  possesses  at  least  the  recommendation 
that  there  exist  well-defined  points  of  demar- 
cation, whether  there  exist  or  not  any  difference 
in  the  properties  of  those  several  portions.  The 
nerve,  in  its  encephalic  portion,  is  partly  within 
and  partly  superficial  to  the  substance  of  the 
brain.  The  superficial  part  is  from  one-half 
to  three-fourths  of  an  inch  in  length,  of  a 
flattened  form,  and  of  very  considerable  size. 
It  presents  a  loose  fascicular  texture,  and  is 
enclosed  within  a  prolongation  of  the  arachnoid 
membrane  sent  off  upon  it  from  the  surface  of 
the  brain ;  this  prolongation  is,  as  in  the  case 
of  all  those  sent  upon  the  vessels  or  nerves,  in 
their  passage  from  that  organ  to  the  parietes  of 
the  cranium,  a  cylindrical  sheath,  within  which 
the  nerve  is  enclosed ;  it  is  at  first  remarkably 
loose,  but  as  the  nerve  recedes  from  the  brain, 
the  membrane  invests  it  more  closely,  and  is 
continued  upon  it  as  far  as  the  ganglion,  from 
which  it  is  reflected  to  the  surface  of  the  canal 
in  which  the  nerve  is  contained.  In  the  last 
particular  the  disposition  of  the  membrane  is 
subject  to  variety,  for  it  is  at  times  continued 
beneath  the  ganglion,  and  partially  invests  the 
trunks  proceeding  from  this  body  before  it  is 
reflected  to  line  the  canal. 

Throughout  this  part  of  the  nerve  the  two 
packets  composing  it  are  connected  by  cellular 
structure  and  vessels,  and  are  enclosed  within 
the  prolongation  of  arachnoid  membrane  just 
described ;  but  there  does  not  appear  to  be  any 
interchange  of  nervous  filaments  between  them, 
and  they  are  connected  so  loosely  that  they  can 
be  separated  from  each  other  with  great  facility. 
They  consist  each  of  numerous  fasciculi  held 
together,  like  the  packets  themselves,  so  loosely 
that  the  latter  can  be  easily  opened  out  and 
decomposed.  The  fasciculi  of  both  packets 
are  irregular  in  size,  some  large,  others  small ; 
those  of  the  larger  are  for  the  most  part  some- 
what smaller  than  those  of  the  lesser,  but  they 
are  much  more  numerous,  amounting,  accord- 
ing to  J.  F.  Meckel,*  to  thirty  or  forty;  while 
those  of  the  lesser  amount,  according  to  the  same 
authority,  only  to  from  nine  to  fourteen.  The 
fasciculi  again  are  composed  of  numerous  and 
delicate  filaments.  The  number  of  the  fila- 
ments is  very  great,  but  differently  estimated 
by  different  authorities;  according  to  Meckel 
those  of  the  greater  packet  amount  to  about 
one  hundred,  collected  into  thirty  or  forty 
fasciculi ;  while,  according  to  Cloquet,f  the 
total  number  of  filaments  contained  by  both 
packets  varies  from  seventy  to  one  hundred, 
of  which  he  allots  five  or  six  to  the  smaller, 
and  the  remainder  to  the  larger  packet.  This 
difference  of  opinion  Meckel  explains  by  sup- 
posing that  fasciculi  have  been  taken  for  fila- 
ments and  not  decomposed,  and  this  appears 

*  Manuel  d'Anatomic. 
t  Anatomic  Descriptive. 


270  FIFTH  PAIR 

very  probable,  inasmuch  as  Cloquet  takes  no 
account  of  fasciculi,  and  in  his  description  of 
the  smaller  packet  it  is  manifest  that  he  has 
assumed  the  fasciculi,  of  which  it  is  composed, 
to  be  filaments,  for  he  does  not  attribute  to  it 
a  greater  number  of  filaments  than  it  contains 
of  fasciculi.    But  if  Cloquet  have  underrated 
the  filaments  of  the  larger  packet,  Meckel 
junior  has  certainly  overrated  the  fasciculi  of 
the  smaller  one.    From  his  account  of  the 
latter,  it  is  to  be  concluded  that  it  contains 
from  three  to  fourteen  fasciculi,  but  either  of 
those  numbers  is  too  great,  as  will  be  seen 
from  an  examination  of  the  subject,  from  which 
it  will  appear  that  they  do  not  exceed  the 
number  attributed  to  them  by  Cloquet.  The 
ultimate  number  of  filaments,  however,  would 
seem  to  be  somewhat  uncertain,  for  it  appears 
to  depend  very  much  upon  the  delicacy  with 
which  the  separation  of  them  may  be  effected  ; 
and  after  all  it  is  not  a  matter  of  any  great 
importance.     According   to  Wrisberg*  and 
Scemmerringl  the  number  of  fibres  contained  in 
the  greater  packet  is  always  less  in  the  foetus 
than  in  the  adult.   The  filaments  of  the  smaller 
are  stated  by  Cloquet  to  be  larger,  softer,  and 
whiter  than  those  of  the  other;  but  with  regard 
to  the  difference  of  size  it  is  probable  that 
this  opinion  has  arisen  also  from  his  having 
assumed  the  fasciculi  to  be  filaments,  inas- 
much as,  when  the  fasciculi  have  been  decom- 
posed, the  filaments  seem  to  be  equally  fine  in 
both  packets  ;  and  for  the  other  points  of  sup- 
posed difference  the  author  has  not  been  able 
satisfactorily  to  observe  any  in  man.    In  other 
animals,  however, — in  some  fish  at  least — a 
remarkable  difference  may  be  observed  between 
the  characters  of  the  ganglionic  and  non-gan- 
glionic  portions,  the  latter  of  which,  in  the 
Cod,  is  much  softer,  and  of  a  darker,  not 
whiter,  colour  than  the  other. 

The  fascicular  and  filamentous  disposition 
which  has  been  described,  is  not,  however, 
presented  by  the  encephalic  portion  of  the 
nerve  through  its  entire  extent,  but  only  in 
that  part  of  it  which  is  superficial  to  the  brain ; 
nor  is  it  acquired  by  it  until  after  it  has  emerged 
one  or  two  lines  from  the  substance  of  the 
organ,  and  then  it  does  not  assume  it  through- 
out at  once,  but  at  first  superficially  and  later 
internally.  The  appearance  of  distinct  fila- 
ments and  fasciculi  in  one  part  and  their  ab- 
sence in  the  other  appears  owing  to  the  exist- 
ence of  neurilema  in  the  former,  for  in  one 
as  in  the  other  the  nervous  matter  appears  to 
be  arranged  in  longitudinal  tracts,  which  pre- 
sent in  one  case  the  form  of  expansions,  and 
in  the  other  are  divided  by  the  neurilema 
into  separate  cords  ;  and  again  the  occurrence 
of  the  filamentous  disposition  earlier  upon  the 
surface  than  internally,  is  attributed  to  the 
superficial  substance  of  the  nerve  being  pro- 
vided with  neurilema  sooner  than  the  inter- 
nal ;  hence  the  length  of  the  substance  of  the 
nerve  without  neurilema  is  greater  internally 

*  Observations  Anatomicre  de  quinto  pari  ner- 
vorum, &c. 

t  In  Imdwig,  Script.  Neurol.  Min.  Ueber  das 
Organ  der  Seele. 


OF  NERVES. 

than  externally,  and  when  the  nerve  has  been 
pulled  away  from  its  attachment  to  the  brain, 
the  rupture  occurring  at  the  point  at  which  the 
neurilema  commences,  the  part  which  is  left 
projects  in  the  middle,  and  presents  a  conical 
eminence  of  white  matter:  this,  as  Cloquet 
justly  remarks,  is  but  an  incidental  appearance, 
and  not  entitled  to  be  considered,  as  it  was  by 
Bichat,*  a  real  tubercle,  from  which  the  nerve 
arose.  In  neither  packet  are  the  fasciculi 
laid  simply  in  apposition ;  in  both,  but  more 
remarkably  in  the  larger,  they  are  connected 
by  frequent  interchanges  of  filaments,  and 
that  to  such  a  degree  that  the  nerve  when 
opened  out  appears  to  form  an  inextricable 
plexus,  in  which  it  is  not  improbable  that  every 
filament  of  it  is  connected  directly  or  indirectly 
with  all  the  others;  this  plexiform  arrangement 
diminishes  as  the  nerve  approaches  the  gan- 
glion, before  reaching  which  the  fasciculi  be- 
come more  distinct. 

The  fifth  nerve  is  attached  to  the  surface  of 
the  brain  on  either  side  of  the  pons  Varolii,  at 
a  distance  of  three-fourths  of  an  inch  from  its 
middle  line.  It  is  attached  to  the  middle 
crus  of  the  cerebellum,  on  its  anterior  inferior 
surface,  about  one-fourth  of  an  inch  from  its 
superior,  and  half  an  inch  from  its  inferior 
margin. 

The  place  of  the  attachment  of  the  nerve  to 
the  exterior  of  the  brain  varies  greatly  in  dif- 
ferent classes  of  animals  ;  in  man,  it  is,  as  has 
been  mentioned,  the  crus  cerebelli  on  either 
side  of  the  pons;  in  the  other  orders  of  the 
Mammalia  it  is  either,  as  in  the  human  sub- 
ject, the  crus  cerebelli,  or,  when  the  pons  is 
less  developed  than  in  man,  the  nerve  is  at- 
tached behind  that  part  between  it  and  the 
trapezium  of  the  medulla  oblongata;  in  the 
other  three  classes  of  vertebrate  animals,  in 
which  the  pons  and  trapezium  are  both  want- 
ing, the  nerve  is  uniformly  attached  to  the  la- 
teral parts  of  the  spina!  bulb.  This  contrast 
is  equally  curious  and  important;  it  affords  us 
a  natural  analysis,  which  will  throw  much  light 
on  the  next  step  in  our  inquiry,  viz.  the  origin 
of  the  nerve,  or  its  ultimate  connexion  with 
the  brain.  It  furnishes  also,  as  has  been  sug- 
gested by  Gall  and  Spurzheim,f  an  explana- 
tion of  the  complication  which  exists  in  the 
human  being,  in  whom  the  great  developement 
and  the  situation  of  the  pons  render  it  neces- 
sary that  the  nerve  should  traverse  it,  in  order 
to  reach  the  surface  of  the  brain. 

At  the  attachment  of  the  nerve  to  the  crus 
cerebelli  in  the  human  subject,  the  non-gan- 
glionic  portion  or  lesser  packet  is  situate  above 
and  to  the  inner  side  of  the  greater.  At  that 
place  it  is  separated  or  separable  into  two 
parts,  while  the  greater  continues  undivided, 
and  hence  the  nerve  is  described  as  having 
three  roots,  one  for  the  greater  and  two  for 
the  lesser  packet.  The  existence  of  two  roots 
for  the  lesser  packet  had  been  announced  by 
Santorini,!  but  they  have  been  more  parti- 

*  Anatomie  Descriptive. 

t  Anatomie  et  Physiologie  du  Systeme  Nerveux. 
X  Observations  Anatomical. 


FIFTH  PAIR  OF  NERVES. 


271 


cularly  and  accurately  described  by  Palletta.* 
They  are  distinguished  by  the  latter  into  supe- 
rior and  inferior,  being  attached  to  the  eras 
cerebelli,  one  above  and  behind  the  other,  and 
they  are  frequently  separated  from  each  other 
at  their  attachment  by  an  interval  of  one  or 
two  lines  or  more.  In  such  case  the  superior 
root  is  superior  and  parallel  to  the  inner  side 
of  the  greater  packet,  while  the  inferior  is  in- 
ternal to  it,  and,  it  may  be,  on  a  level  with  its 
inferior  surface;  hence,  in  such  instances,  the 
greater  packet  corresponds  to  the  interval  be- 
tween the  roots  of  the  lesser,  and  the  inferior 
root  of  the  lesser,  in  its  course  from  the  brain, 
is  placed  at  first  along  the  inner  side  of  the 
greater  packet,  while  the  superior  descends 
internal  to  the  greater  packet,  and  joins  the 
inferior  beneath  it  to  constitute  the  lesser 
packet.  This  is  not,  however,  uniformly  the 
relation  of  the  roots  of  the  nerve  at  their  at- 
tachment to  the  crus,  for  the  distance  at  which 
they  are  placed  from  each  other  varies  very 
much;  in  some  instances  the  roots  of  the  lesser 
packet  are  perfectly  distinct  and  separated  by 
the  interval  mentioned,  the  inferior  being  either 
in  immediate  contact  with  the  greater  packet, 
and  even  entering  the  crus  through  the  same 
aperture,  or  being  separated  from  it  by  an 
interval  varying,  according  to  J.  F.  Meckel, 
from  a  quarter  of  a  line  to  a  line;  while  in 
others  the  roots  of  the  lesser  packet  are  not 
manifestly  distinct,  but  the  fasciculi  of  which 
they  consist  are  attached  to  the  crus  in  an  un- 
interrupted series  reaching,  from  the  attachment 
of  the  greater  packet,  to  within  a  line  or  less  of 
the  posterior  face  of  the  crus,  and  separated 
the  one  from  the  other  by  trifling  intervals;  in 
the  latter  case  the  lesser  packet  is,  for  the  most 
part,  altogether  superior  to  the  greater  at  their 
attachment.  But  even  in  this  the  lesser  is  still 
distinguishable  into  two  sets  of  fasciculi,  which 
take  different  routes  through  the  substance  of 
the  crus,  one  traversing  it  nearer  to  its  ante- 
rior, the  other  to  its  posterior  surface.  It  has 
been  already  stated  that  the  lesser  packet  of 
the  nerve  is  characterized  by  the  absence  of  a 
ganglion;  it  also  has  no  connexion  with  the 
ganglion  of  the  larger  packet,  but  passes  it 
without  entering  into  it,  and  then  becomes 
attached  to  one  of  the  trunks  proceeding  from 
it;  it  is  further  maintained  to  be  distributed 
ultimately  into  those  branches  which  are  given 
by  the  third  division  of  the  fifth  to  the  muscles 
of  mastication.  Palletta-I  concluded  from  these 
circumstances  that  it  was  a  nerve  distinct  from 
the  remainder  of  the  fifth  ;  and  observing  that 
the  superior  root  was  principally  consumed  in 
the  temporal  muscle,  and  the  inferior  in  the 
buccinator,  forming  the  long  buccal  nerve, 
he  called  the  former  the  "  crotaphitic,"  and  the 
latter  the  "  buccinator"  nerves.  The  distri- 
bution of  the  leaser  packet  to  the  muscles  of 
mastication  has  been  confirmed  by  Mayo  ];  from 

*  Pallet'.a,  De  Nervis  crotaphitico  et  buccina- 
torio,  an.  1784.  Script.  Neurol.  Min.  Select.  Lud- 
wig. 

t  Op.  cit. 

t  Commentaries,  and  Physiology. 


the  dissection  of  the  nerve  in  the  ass.  He 
differs,  however,  from  Palletta  with  regard  to 
its  distribution  to  the  buccinator,  which  he 
denies :  this  point  will  come  under  considera- 
tion again.  It  has  been  proposed  by  Eschncht* 
to  denominate  it  the  masticatory  nerve. 

The  place  at  which  the  nerve  is  attached  to 
the  surface  of  the  brain  in  the  human  subject 
is  to  be  regarded  only  as  the  point  at  which  it 
enters  or  emerges  from  the  substance  of  the 
organ,  inasmuch  as  it  can  be,  without  difficulty, 
followed  to  a  much  deeper  part,  and  the  fibres 
of  the  crus,  which  are  transverse  to  those  of  the 
nerve,  manifestly  separate  from  each  other,  at 
the  entrance  of  the  nerve,  to  allow  it  a  passage. 
The  larger  packet  of  the  nerve  is  that  whose 
course  into  the  brain  can  be  most  easily  traced; 
this  circumstance  depends  partly  upon  the 
greater  size  of  the  packet,  and  partly  upon  the 
fact  that,  for  the  most  part,  its  tracts  are  not 
separated  from  each  other  by  those  of  the  crus, 
but  traverse  that  part  in  a  body,  the  fibres  of 
the  crus  seeming  to  be  simply  laid  in  apposi- 
tion with  it,  and  connected  to  it  by  some  deli-, 
cate  medium  ;  while  those  of  the  lesser  are,  in 
the  greater  number  of  instances,  separated  from 
each  other,  or  even  interlaced  with  those  of  the 
crus ;  hence  the  fibres  of  the  crus  may  be  easily 
raised,  without  injury  to  the  nerve,  from  the 
larger  packet,  and  its  course  be  displayed, 
while  the  lesser  cannot  be  followed  but  with 
difficulty.  The  larger  is,  however,  subject  to 
variety  in  the  latter  respect ;  in  many  instances 
the  fasciculi  of  the  crus  do  traverse  and  divide 
it,  and  very  frequently  near  its  ultimate  attach- 
ment, and  this  circumstance,  when  it  occurs, 
renders  the  pursuit  of  its  course  more  difficult ; 
but  even  here  the  fasciculus  merely  traverses 
it,  and  its  tracts  are  not  permanently  separated, 
but  reunite  after  the  fasciculus  has  passed. 
The  course  of  the  packet  may  be  exposed  to  a 
considerable  extent  even  in  the  recent  brain  ; 
but  for  the  satisfactory  determination  of  the 
point,  it  is  necessary  that  the  brain  be  prepared 
by  some  of  the  methods  recommended  for  that 
purpose,  of  which  immersion  in  strong  spirit  is 
by  far  the  best,  nor  does  it  require  much  time, 
for  the  substance  will  be  found  to  separate 
more  easily  when  it  has  acquired  only  a  certain 
degree  of  firmness,  than  when  hardened  to  the 
degree  which  long  immersion  produces;  the 
plan  which  the  author  has  found  most  success- 
ful has  been  to  commence  the  dissection  early, 
to  return  to  it  frequently,  and  at  each  time  to 
pursue  it  so  far  and  so  far  only  as  it  was  satis- 
factory. The  course  of  the  larger  packet  is 
also  beneath  and  before  that  of  the  lesser,  and 
hence,  in  the  usual  mode  of  dissection, in  which 
the  brain  is  reversed,  it  presents  itself  first. 
Its  direction  is  backward,  downward,  and  in- 
ward, toward  the  upper  extremity  of  the  spinal 
bulb ;  in  its  course  the  packet  first  traverses 
the  middle  crus  of  the  cerebellum  from  its  an- 
terior toward  its  posterior  surface,  and  from  its 
superior  toward  its  inferior  margin  ;  it  pursues 
this  course  until  it  has  reached  the  back  of  the 
crus,  and  descended  so  low  as  its  inferior  mar- 

*  Journal  de  Physiologie,  t.  vi. 


272 


FIFTH  PAIR  OF  NERVES. 


gin ;  it  is  then  situate  in  the  angle  formed  by 
the  three  peduncles  of  the  cerebellum  at  their 
junction  with  the  hemisphere;  behind  the 
middle,  beneath  the  superior  and  above  the  in- 
ferior, and  before,  or  in  common  language,  be- 
neath the  floor  of  the  fourth  ventricle.  Thus 
far  the  course  of  the  nerve  may  be  ascertained 
without  much  difficulty;  it  is  probably  the 
same  point  to  which  Santorini  had  traced  it, 
as  described  in  his  '  Observations  Anatomicae,' 
in  1724,  and  from  which  Scemmerring  has 
more  expressly  stated  it  to  be  derived,  in  his 
work  '  De  corporis  humani  fabrica,'  pub- 
lished 1798,  in  which  he  states  "that  it  ap- 
pears to  arise  almost  from  the  very  floor  of  the 
fourth  ventricle."  *    At  the  point  last  described 

Fig.  140. 


Lateral  view  of  the  pons,  spinal  bulb,  and  course  of 
the  Fifth  Nerve  in  man. 

1  Pons  Varolii. 

2  Spinal  bulb. 

3  Olivary  body. 

4  Spinal  cord. 

5  Superior  peduncle  of  cerebellum. 

6  Cut  surfaces  of  middle  ditto. 

7  Inferior  peduncle  of  cerebellum. 

8  Cut  surface  of  crus  cerebri. 

9  Ganglion  of  Fifth  Nerve  reversed. 

10  Ganglionic  portion  of  the  nerve. 

11  Non-ganglionic  portion  of  Fifth  Nerve. 

11  Roots  of  non-ganglionic  portion. 

12  Eminence  at  the  insertion  of  both  portions  of 

the  Fifth  Nerve. 

13  Fasciculus  to  anterior  column  of  spinal  cord- 

14  Fasciculus  to  posterior  column. 

15  Auditory  nerve. 

16  Portio  dura. 

17  Posterior  roots  of  superior  cervical  nerves. 

*  Santorini,  however,  appears  to  have  followed 
the  nerve  out  into  the  spinal  bulb,  though,  as  will 
be  seen,  he  did  not  succeed  in  determining  its  real 
and  ultimate  connection. 


the  greater  packet  is  attached  to  the  side  of  the 
medulla  oblongata.  The  point  of  attachment 
is  very  close  to  the  interior  of  the  fourth  ven- 
tricle, being  separated  from  it  only  by  a  thin 
lamina,  which  is  little,  if  any  thing,  more  than 
the  "  epithelium"  of  Reil :  it  is  situate  in  the 
angle  formed  by  the  peduncles  of  the  cerebel- 
lum, behind  the  middle  one,  by  the  outer 
margin  of  the  pons,  and  posterior  to  it,  and 
above  its  lower  one  :  it  is  also  superior  to  the 
attachment  of  the  auditory  nerve,  separated 
from  it  by  an  interval  of  some  lines. 

We  shall,  in  the  next  place,  direct  attention 
to  the  course  and  connection  of  the  lesser 
packet  of  the  nerve. 

In  none  of  the  authorities  which  the  author 
has  had  an  opportunity  of  consulting,  has  he 
found  a  particular  origin  assigned  to  the  lesser 
packet.  By  most  anatomical  writers  it  is  over- 
looked ;  J.  F.  Meckel  states  that  it  can  be 
traced  a  certain  way  into  the  crus,  but  he 
goes  no  further;  Mayo  asserts  that  the  lesser 
portion  arises  close  upon  the  greater,  and,  in  a 
sketch  of  the  origins  of  the  nerves  given  by  him 
in  his  Physiology,  it  is  represented  traversing 
the  crus  cerebelli,  as  a  single  fasciculus,  above 
and  behind  the  greater,  and  attached  to  some 
part  above  that  from  which  the  greater  is  re- 
presented to  arise :  but  still  the  origin  is  not 
defined,  and  it  is  manifestly  intended  to  be 
distinct  from  that  of  the  greater  packet. 

The  author  has  succeeded,  as  it  appears  to 
him,  satisfactorily  in  tracing  both  the  roots  of 
the  lesser  packet  to  a  destination  for  which  he 
was  not  prepared ;  at  setting  out  he  expected 
to  have  found  the  origin  of  the  lesser  different 
from  that  of  the  greater  packet,  and  to  have 
followed  it  to  a  prolongation  of  the  anterior 
columns  of  the  spinal  cord,  as  has  been  stated 
by  Harrison  ;*  it  was  therefore  with  surprise 
that,  after  a  patient  dissection,  he  succeeded  in 
tracing  both  its  roots  to  the  same  point,  to 
which  the  greater  packet  is  attached,  behind 
the  middle  crus  of  the  cerebellum  (see  Jig.  140, 
12);  both  the  roots  traverse  the  crus,  as  the 
greater  does,  the  inferior  very  frequently  in 
company  with  and  internal  to  the  greater 
packet,  or  separated  from  it  by  a  very  thin 
stratum  of  the  substance  of  the  crus,  the 
superior  near  to  the  superior  surface  of  that 
part,  and  separated  from  the  greater  packet  by 
an  interposed  stratum  of  two  or  more  lines; 
the  course  of  the  latter  is  so  near  to  the  surface 
of  the  crus,  that  it  can  frequently  be  traced  for  a 
considerable  way  by  the  eye  without  dissec- 
tion :  they  present,  in  their  mode  of  traversing 
the  crus,  two  remarkable  varieties  ;  in  some  in- 
stances the  fasciculi,  of  which  they  are  com- 
posed, are  separated  from  each  other  and  even 
interlaced  with  those  of  the  crus,  and  in  such 
the  pursuit  of  them  is  intricate  and  difficult ; 
in  others  they  pass  in  two  distinct  packets,  and 
in  these  they  are  more  easily  followed.  As 
they  proceed  they  approach  the  greater  packet, 
so  that  the  interval  between  them  and  it  gradu- 
ally diminishes,  and  having  traversed  the  crus, 
they  are  both  attached  below  and  behind  it  to 

*  Dublin  Dissector. 


FIFTH  PAIR  OF  NERVES. 


273 


the  same  part  as  the  greater  packet,  and  poste- 
rior to  it.  (See  fig.  1 40).  This  view  of  the  con- 
nection of  the  lesser  packet,  if  confirmed,  must 
lead  to  interesting  results  with  regard  to  the  rela- 
tions of  the  two  portions  of  the  fifth  nerve  at  least ; 
it  will  at  all  events  decide  the  question  as  yet  in 
dispute,  whether  they  are  to  be  regarded  as 
distinct  nerves,  or  parts  of  the  same  ;  upon 
this  point  further  light  will  be  thrown  by  the 
disposition  of  the  same  part  in  fish,  in  which 
the  source  of  the  uncertainty  prevailing  with 
regard  to  the  nerve  in  the  higher  classes  does 
not  exist  to  the  same  amount ;  inasmuch  as  the 
ganglionic  and  non-gangl ionic  divisions  of  the 
nerve  seem  for  the  greater  part  associated  in 
their  distribution. 


Fig.  141. 


Back  view  of  pons,  bulb,  and  course  of  the  Fifth 
Nerve  in  man, 

18  Tubercula  quadrigemina. 

19  Continuation  upward  of  the  tract  from  which 

the  Fifth  Nerve  arises. 
The  other  referenoes  indicate  the  same  parts  as 
in  the  preceding  figure. 

When  the  adjoining  matter  has  been  care- 
fully cleared  away  from  the  part  to  which  the 
packets  of  the  nerve  are  attached,  that  part  ap- 
pears to  be  a  longitudinal  tract  of  a  yellowish- 
white  colour,  composed  of  fibres  running  in  the 
same  direction,  and  capable  of  being  followed 
both  upward  and  downward  :  upward  this  tract 
seems  continued  beneath  the  superior  peduncle 
of  the  cerebellum;*  downward  it  descends  from 

*  Of  the  nature  of  the  structure  continued  up- 
ward from  the  attachment  of  the  nerve  the  author 
is  not  satisfied  :  it  presents,  when  cleared,  the  ap- 
pearance given  to  it  in  fig.  141 , 19,  but  it  is  very  cine- 
ritious  in  character,  and  he  is  not  prepared  to  say 
whether  it  be  a  continuation  of  the  tract  from  which 
the  nerve  appears  to  arise,  or  a  part  of  the  floor  of 
the  fourth  ventricle  at  its  upper  extremity,  con- 
nected to  the  attachment  of  the  nerve  :  the  mode 
in  which  the  nerve  arises  in  the  bird  and  the  turtle 
appears  to  the  author  opposed  to  the  opinion  that 
the  tract  to  which  the  nerve  is  attached  is,  in  them 
at  least,  any  thing  more  than  a  continuation  or 
VOL.  II. 


behind  the  pons  into  the  spinal  bulb,  and  after 
a  short  course  divides  into  two  cords,  one  for 
each  column  of  the  spinal  marrow  (see  Jigs. 
140,  141).  At  the  entrance  of  the  tract  into 
the  bulb  it  is  situate  deep,  before  the  floor  of 
the  fourth  ventricle  and  behind  the  superficial 
attachment  of  the  two  portions  of  the  seventh 
pair,  which  must  be  separated  from  each  other 
and  displaced  in  order  that  it  may  be  ex- 
posed :  externally  the  tract  corresponds  to  the 
peduncles  of  the  cerebellum,  and  is  united  in- 
ternally to  the  cineritious  matter  of  the  floor 
of  the  ventricle.  At  the  point  of  attachment 
the  tract  presents  a  somewhat  prominent  en- 
largement, (Jigs.  140,  141,  12,)  which  the  au- 
thor will  venture  to  call  an  eminence,  though 
with  hesitation,  lest  it  be  considered  an  ex- 
aggeration, from  which  the  nerve  may  be  held 
to  arise. 

It  is  said  that  the  nerve  may  be  held  to  arise 
from  this  tract,  because,  though  it  be  certainly 
not  its  ultimate  connection  with  the  brain,  and 
though  cords  can  be  traced  from  it  to  more 
remote  parts,  yet  the  union  of  the  cords  at  the 
point,  and  the  attachment  of  both  portions  of 
the  nerve  to  it,  seem  to  mark  it  as  the  origin 
of  the  nerve  ;  the  change  of  character  too  which 
will  be  described  as  occurring  at  the  attach- 
ment of  the  nerve,  countenances  the  opinion 
that  the  tract  is  not  simply  a  continuation  of 
the  nerve. 

It  may  be  doubted  whether  the  eminence 
really  exist,  or  whether  it  be  not  merely  the 
result  of  dissection  :  the  author  will  not  insist 
upon  it,  but  several  considerations  induce  him 
to  consider  it  real :  in  the  first  place,  he  almost 
uniformly  finds  it,*  and  secondly,  it  seems  to 
be  a  common  point  to  the  two  portions  of  the 
nerve  and  to  the  other  cords,  which  form  part 
of  its  encephalic  connections  ;  and  lastly,  this 
view  is  corroborated  by  the  disposition  of  the 
same  part  in  other  animals ;  for  a  similar  ap- 
pearance will  be  found,  at  the  attachment  of 
the  nerve  behind  the  pons,  in  other  mammalia 
as  well  as  in  man  after  the  separation  of  the 
adjoining  matter,  e.  g.  in  the  horse ;  and  it  is 
even  asserted  by  Desmoulins  that  an  eminence 
may  be  observed  naturally  upon  the  floor  of 
the  fourth  ventricle,  in  some  animals,  at  the 
attachment  of  the  nerve.  His  statement  is : 
"  on  observe  meme  dans  les  rongeurs,  les 
taupes,  et  les  herissons,  un  petit  mamelon  ou 
tubercle  sur  l'extremite  ant6rieure  du  bord  du 
ventricule  ;  mamelon,  clans  tequel  se  conlinuent 
les  fibres  posterieures  de  la  cinquieme  paire,  et 
de  l'acouslique."  When  the  tract  has  reached 
the  point  at  which  the  inferior  peduncle  of  the 
cerebellum  first  inclines  outward  toward  the 
hemisphere,  it  separates,  as  has  been  stated,  into 
two  parts  or  cords,  (see Jigs.  140,  141,)  destined, 
one,  as  is  already  known,  to  the  posterior,  the 
other,  according  to  the  author's  belief,  to  the  an- 
terior column  of  the  spinal  cord.  The  course  and 
disposition  of  these  cords  are  remarkable  and 

root  of  the  nerve,  but  admitting  this,  he  cannot 
satisfy  himself  that  it  is  to  be  regarded  in  the  same 
light  in  the  Mammalia. 

*  The  attachment  of  both  the  packets  must  be 
made  out,  else  the  enlargement  will  not  appear. 

T 


274 


FIFTH  PAIR  OF  NERVES. 


apparently  contrary  to  analogy  ;  they  are  dis- 
tinguishable into  anterior  and  posterior,  but 
they  descend,  the  anterior  to  the  posterior,  and 
the  posterior  to  the  anterior  columns.  The  an- 
terior cord  is  by  much  the  larger,  and  is  pro- 
longed through  the  inferior  peduncle  of  the 
cerebellum,  until  at  the  inferior  extremity  of 
the  bulb  it  is  continued  into  the  longitudinal 
fasciculi  of  the  corresponding  posterior  column 
of  the  spinal  marrow ;  it  is  situate  along  the 
outer  side  of  the  olivary  body,  but  separated 
from  it  by  a  slight  interval,  nor  does  it  seem 
to  have  any  connection  with  that  body  :  it  is 
imbedded  in  the  substance  of  the  superior  part 
of  the  peduncle,  situate,  however,  nearer  to  its 
anterior  than  its  posterior  surface,  and  laid 
obliquely  across  its  fibres  as  they  pass  outward 
toward  the  hemisphere  of  the  cerebellum  ;  but 
as  it  proceeds  it  becomes  gradually  more  super- 
ficial, gains  the  outer  side  of  the  peduncle,  and 
at  the  lower  extremity  of  the  bulb  is  actually  at 
its  surface  almost  immediately  behind  the  lateral 
fissure  of  the  cord  and  the  posterior  roots  of  the 
superior  cervical  nerves.  The  existence  and 
course  of  this  cord  have  been  first  established 
and  described  by  Rolando  in  his  "  Saggio  sopra 
la  vera  Struttura  del  Cervello,"  and  also  in  a 
memoir  upon  the  Anatomy  of  the  Medulla 
oblongata,  published  in  the  fourth  volume  of 
the  Journal  of  Physiology. 

The  posterior  cord  is  much  smaller  than  the 
former  ;  it  descends  behind  the  inferior  pedun- 
cle of  the  cerebellum,  as  it  passes  outward 
into  the  hemisphere,  and  upon  the  posterior 
aspect  of  the  spinal  bulb ;  enters  the  posterior 
fissure  of  the  bulb,  between  the  posterior  py- 
ramids, and  can  be  traced  some  way  down- 
ward, in  the  bottom  of  the  fissure,  along  the 
back  of  the  anterior  column  of  the  same  side, 
into  which  it  appears  to  be  ultimately  con- 
tinued.   (Figs.  140,  141,  13.) 

The  preceding  account  of  the  encephalic 
connections  of  the  fifth  nerve  differs  very  much 
from  that  adopted  by  some  of  the  highest 
modern  authorities.  It  is  not  necessary  to 
allude  to  the  opinions  entertained  upon  the 
point,  before  the  course  of  the  nerve  had 
ieen  particularly  inquired  into;  but,  accord- 
ing to  some  of  the  most  recent,  the  nerve 
arises  from  the  groove  between  the  restiform 
and  olivary  bodies,  and  from  the  olivary  bodies 
themselves.  Such  is  the  view  given  of  the 
origin  of  .the  nerve  by  Gall  and  Spurzheim 
in  their  fifth  plate  of  the  brain,  in  which  the 
nerve  is  represented  breaking  up,  on  the  out- 
side of  the  olivary  body,  into  several  fasciculi, 
which  plunge  obliquely  into  it.  In  their 
account*  of  the  course  of  the  nerve  into  the 
brain  they  state,  "  on  peut  aisement  suivre  son 
cours  entier  jusq'au  dessous  du  cote  exterieur 
des  corps  olivaires  ;"  this  might  be,  perhaps, 
interpreted  to  mean  beyond  the  ulivuries, 
reference  being  had  to  the  relations  of  those 
bodies  in  the  erect  posture ;  but  from  the 
representation  given  it  is  obvious  that  the  in- 
tended meaning  is,  that  the  nerve  can  be  fol- 

1  Anatomie  et  Physiologie  du  Systerae  Ner- 
vciix,  loin.  i.  p.  107. 


lowed  to  beneath,  i.  e.  underneath,  their  outer 
side,  the  brain  being  placed  in  the  manner 
ordinarily  adopted  for  dissection,  in  which 
the  anterior  aspect  of  the  olivaries  is  rendered 
superior;  indeed  their  representation  is  alto- 
gether incompatible  with  the  opinion  that  they 
had  traced  the  nerve  beyond  the  bodies. 

Such  al  so  is  the  opinion  of  J.  F.  Meckel,* 
according  to  whom  the  nerve  "  passes  under 
the  posterior  peduncle  of  the  cerebellum, 
along  the  outer  side  of  the  pons,  toward  the 
groove  between  the  olivary  and  restiform  bo- 
dies, where  it  arises  in  part  from  the  groove 
and  in  part  from  the  olivary  eminences." 
Cloquetf  likewise  states  the  nerve  to  arise 
between  the  olivary  and  restiform  bodies,  and 
has  adopted  and  copied,  in  his  late  work,} 
the  view  given  of  its  origin  by  Call  and  Spurz- 
heim. Further,  the  discovery  of  this  origin  of 
the  nerve  has  been  attributed  by  Meckel§  and 
others  to  Santorini. 

It  is  a  hardy  thing  to  contradict  such  au- 
thorities as  have  been  quoted,  and  the  influence 
which  they  justly  carry  with  them  has  made 
the  author  hesitate  before  adopting  a  contrary 
opinion  ;  but  if  reference  be  made  to  the  work|j 
of  Santorini  on  the  point,  it  will  be  found  that 
he  nowhere,  in  his  account  of  the  origin  of  the 
nerve,  assigns  the  groove  between  the  restiform 
and  olivary  bodies  as  its  situation  in  the  spinal 
bulb,  as  will  appear  from  the  following  extract, 
the  only  paragraph  of  his  account  in  which  he 
particularizes  it,  and  in  which  he  supposes  it 
to  be  situate  between  the  olivary  and  pyramidal 
bodies :  "  Unde  in  interiorem  medullas,  ob- 
longata? caudicem  conjectus,  fere  inter  olivaria 
et  pyramidalia  corpora  locatus,  quo  demum 
pergat,  cum  tenuium  fibrarum  implexus,  turn 
earumdem  mollitudo,  ne  consequerer,  omnino 
prohibuere  ;"  from  which  it  is  plain,  as  has 
been  stated,  that  he  supposed  the  nerve  to  be 
between  the  two  latter  bodies ;  and  also  that 
he  had  not  been  able  to  trace  it  to  any  particular 
destination,  although,  in  a  succeeding  para- 
graph, he  conjectures  the  olivary  body  to  be 
its  source :  hence  there  is  reason  to  conclude 
that  succeeding  anatomists  have  assumed  his 
conjecture  to  be  an  established  fact,  and  have 
modelled  their  accounts  and  representations 
accordingly.  Moreover,  since  the  olivary  bodies 
.do  not  exist  in  the  lower  classes  of  animals, 
it  is  not  likely  that  they  should  be  points  of 
origin  or  attachment  for  nerves ;  in  fine,  the 
author  has  so  uniformly  succeeded  in  tracing 
the  nerve  to  the  destination  which  has  been 
described,  that  he  is  satisfied  of  the  accuracy 
of  it,  in  which  he  is  confirmed  by  the  fact  that 
the  account  here  given  accords  with  the  opinions 
of  Santorini,  Scemmerring,  and  Rolando,  so 
far  as  that  of  the  first  has  been  determined  to 
be  accurate,  or  as  those  of  the  others  extend  : 
the  particulars  in  which  it  differs  from,  or  rather 
in  which  it  goes  beyond  these,  rest  upon  the 
author's  authority  and  remain  to  be  confirmed, 

*  Manuel  d'Anatoinie,  French  edit, 
f  Traite  d' Anatomie  descriptive. 
X  Anatomie  de  l'Homme. 
S,Seenote5,  p.  82,  op.  cit.  vol.  ii. 
|  Observatioiies  Anatomies. 


FIFTH  PAIR  OF  NERVES. 


275 


viz  .  the  attachment  of  the  two  packets  to  the  same 
point,  the  existence  of  the  eminence  at  the  inser- 
tion, and  that  of  a  cord  of  communication  with 
the  anterior  column  of  the  spinal  marrow. 

The  encephalic  connections  of  the  nerve, 
as  detailed,  are  corroborated  by  those  to  be 
observed  in  inferior  animals.  In  those  Mam- 
malia in  which  the  pons  is  but  little  deve- 
loped, the  nerve  is  attached  between  that  part 
and  the  trapezium ;  in  those  instances  in  which 
the  pons  is  more  so,  the  nerve  is  attached, 
superficially,  not  actually  behind  that  part, 
but  near  to  its  posterior  margin;  with  little 
trouble  it  can  be  followed  to  the  back  of  the 
pons,  where  it  is  attached,  as  in  Man,  to  the 
medulla  oblongata,  the  point  of  attachment 
presenting  here  also,  after  the  separation  of  the 
adjoining  matter,  the  appearance  of  an  emi- 
nence or  tubercle,  from  whence  a  cord  de- 
scends beneath  the  trapezium  into  the  lateral 
column  of  the  spinal  bulb.  This  cord  is  of 
great  size  in  many  animals ;  and  in  some  can 
be  seen  distinctly,  without  dissection,  upon 
the  surface  of  the  spinal  bulb,  in  consequence 
of  the  degree  to  which  it  projects :  it  is  well 
expressed  in  the  delineation  of  the  brain  of  the 
calf  in  the  third  plate  of  Gall  and  Spurzheim, 
and  in  that  of  the  brain  of  the  horse  in  fig.  275 
of  M.  Serres'  Illustrations  of  the  Comparative 
Anatomy  of  the  Brain. 

In  Birds,  Reptiles,  and  Fish,  neither  pons, 
trapezium,  nor  olivary  bodies  exist,  and  the 
nerve  is  attached  to  the  lateral  part  of  the 
spinal  bulb  at  its  superior  or  anterior  extremity, 
and  to  its  lateral  column — the  prolongation  of 
the  superior  column  of  the  spinal  cord.  In 
all  three  the  point  of  attachment  is  situate  a 
little  way  from  the  back  of  the  bulb  and  be- 
neath the  floor  of  the  ventricle,  the  cineritioua 
stratum,  of  which  the  latter  consists,  being 
directly  connected  to  the  back  of  the  nerve. 
In  Birds  (fig.  142)  the  continuation  of  the  nerve 

Fig.  142. 


Brain  and  Fifth  Nerves  of  the  Goose. 

1  Inferior  surface  of  cerebrum. 

2  Spinal  bulb.  3  Ganglia  of  fifth  nerves. 

4  Root  of  nerve  from  lateral  column  of  the  bulb 
exposed  by  turning  aside  the  superficial  stratum  of 
that  part. 

5  First  division  of  the  fifth.  6  Second  do. 
7  Third  do.                        8  Auditory  nerve. 
On  one  side  (the  reader's  right)  the  non-gan- 

glionic  fasciculus  has  been  traced  beneath  the  gan- 
glion into  the  third  division  of  the  nerve. 


can  be  traced  downward  along  the  side  of  the 
bulb  toward  the  spinal  cord,  and  without  diffi- 
culty, inasmuch  as  it  is  superficial  and  is  not 
crossed  by  a  trapezium,  as  in  the  Mammalia. 

In  the  Turtle  the  nerve  can  be  traced  in  like 
manner  from  the  point  of  attachment  down- 
ward into  the  lateral  column ;  and  in  Fish  the 


Fig.  143. 


Origin  of  nerve  in  Turtle. 

1  Spinal  bulb. 

2  Fifth  nerves. 

The  pin  is  passed  between  the  ganglionic  and 
non-ganglionic  fasciculi,  the  latter  being  continued 
into  the  third  division. 

3  Ganglion. 

4  First  division  of  the  nerve. 

5  Second  do. 

6  Third  do. 

attachment  is  in  all  essentials  similar :  the  com- 
parative small ness  of  the  bulb  and  the  direc- 
tion which  the  nerve  takes  in  its  course  out- 
ward, make  it  resemble  the  spinal  nerves  more 
than  in  the  other  classes;  but  its  encephalic 
connection  is  strictly  the  same,  namely,  to  the 
lateral  column  of  the  bulb  beneath  the  floor  of 
the  ventricle.  In  the  Cod,  after  the  removal  of 
the  floor  of  the  ventricle  from  the  back  of  the 
nerve,  the  latter  may  be  followed  for  some  way 
into  the  column,  though  neither  to  the  same 
extent  nor  so  satisfactorily  as  in  the  bird  or  the 
Turtle;  and  in  the  Ray,  while  the  two  inferior 
fasciculi  of  the  nerve — for  in  this  fish  it  consists 
originally  of  three — are  connected  in  the  usual 
mode  to  the  lateral  column,  the  superior  is 
attached  to  a  convolution  formed  by  the  floor, 
in  consequence  of  a  greater  developement  of  its 
margin.  In  the  Cod  the  convolution  adverted 
to  does  not  exist,  but  the  floor  of  the  ventricle 
cannot  be  raised  from  the  nerve  without  destroy- 
ing a  connection  of  some  kind  between  them. 
In  the  latter  fish  the  fifth  nerve  is  attached 
before  and  rather  superior  to  the  auditory  nerve, 
and  the  two  nerves  are  quite  distinct  as  far  as 
the  point  of  attachment,  but  there  they  are  in 

t  2 


'  Brain  and  Fifth  Nerves  of  the  Cod. 

1  Non-ganglionic  portions  (on  the  reader's  left        c  Third  do 
side)  separated  from  the  ganglionic  and  thrown 
back. 

2  Ganglionic  portion. 
a  First  branches  of  both  portions. 
b  Second  do.  " 


d  Fourth  branch  derived  from  both, 
e  Fifth  branch  derived  only  from  the  ganglionic. 
The  third  division  has  been  removed  on  the  left 
side. 


immediate  apposition  and  appear  to  have  the 
same  source.  In  the  Ray  it  is  different;  in  it 
(he  auditory  seems  merely  a  branch  of  the 
fifth  (Jig.  145,  7)  given  off  from  its  posterior 


ganglionic  fasciculus  about  three  lines  from  its 
attachment  to  the  spinal  bulb,  and  before  the 
formation  of  its  ganglion. 

After  the  preceding  details  it  must  seem 


Fig.  14.5. 


Brain  and  Fifth  Nerves  of  the  Bay. 


a  Anterior  ganglionic  portion  of  the  fifth  nerve. 
b  Posterior  do. 

c  Non-ganglionic  portion.  On  the  reader's  left 
it  is  laid  back  to  display  its  connexion  with  the 

extraordinary  if  the  nerve  in  the  higher  ani- 
mals differed,  in  its  ultimate  connection  with 


posterior  ganglionic  ;  on  the  right  it  is  in  situ. 
e  First  branches  of  the  two  portions. 
f  Second  do. 
7  Auditory  nerves. 

the  brain,  so  very  much  from  that  in  the  in- 
ferior, as  it  is  represented  by  some  to  4o. 


FIFTH  PAIR  OF  NERVES. 


Yet  it  is  asserted  by  M.  Serres,*  who  has 
founded  his  opinion  upon  the  observations 
which  he  has  made  upon  the  successive  de- 
velopement  of  the  brain  and  nerves  in  the 
embryo  of  vertebrate  animals,  that  in  the 
Mammalia  the  nerve  is  implanted  upon  the 
trapezium.  Such  is  the  form  of  expression  by 
which  he  intends,  as  the  author  understands, 
the  ultimate  connection  of  the  nerve  with  the 
brain.  Now,  in  the  first  place,  we  have  al- 
ready seen  where  that  connection  is  in  those 
animals  in  which  the  trapezium  does  not  exist, 
and  it  appears  to  the  author  reasonable  to  con- 
clude that  similar  nerves  have  similar  or  ana- 
logous attachments  in  the  several  classes  of 
animals,  however  the  parts  with  which  they 
are  connected  may  be  complicated  or  ob- 
scured by  superadded  structures.  In  the  second 
place  the  trapezium  can  be  regarded  only  as  a 
superadded  structure,  and  is  not  among  those 
parts  from  which  nerves  are  likely  to  arise, 
being  itself  but  a  commissure:  and,  thirdly, 
the  situation  and  connections  of  the  part  to 
which  the  nerve  is  attached,  are  altogether  in- 
compatible with  the  opinion  that  it  is  the  tra- 
pezium, inasmuch  as  the  latter  is  situate  be- 
fore the  cords,  which  ascend  from  the  anterior 
columns  of  the  spinal  cord  to  the  crura  cerebri, 
while  the  structure  with  which  the  nerve  is 
connected  is  posterior  to  them.  For  these 
reasons  the  author  concludes  that  M.  Series 
has  mistaken  the  place  of  the  nerve's  attach- 
ment in  the  Mammalia. 

In  conclusion,  the  representation  of  the  ori- 
gin of  the  nerve,  which  appears  to  the  writer  to 
be  the  most  remote  of  all  from  the  real  one,  is 
that  given  by  Swan,  in  his  plates  of  the  nerves 
lately  published,  in  which  the  fifth  is  re- 
flected into  the  auditory  nerve :  such  a  con- 
nection is  merely  artificial  and  does  not  really 
exist ;  it  can  be  produced  only  by  stopping  short 
in  the  pursuit  of  the  fifth  nerve,  and  mould- 
ing it  into  the  anterior  root  of  the  auditory, 
which  is  in  contact  with  it. 

This  view  of  its  encephalic  attachment  has 
probably  originated  in  the  intimate  connection 
known  to  exist  between  the  two  nerves  in  in- 
ferior animals.  The  complication  of  the  cere- 
bral connection  of  the  nerve  in  the  higher 
animals  may  be  now  better  understood.  In 
those,  in  which  the  pons  and  trapezium  do  not 
exist,  the  nerve  emerges  directly  from  the 
spinal  bulb,  in  a  manner  similar  to  the  ad- 
joining nerves ;  but  in  those,  in  which  the 
bodies  alluded  to  are  present,  inasmuch  as  the 
attachment  of  the  nerve  is  behind  them,  it  can 
reach  the  surface  only  by  either  passing  be- 
tween them,  or  traversing  their  substance. 
Hence,  if  the  nerve  simply  traverse  them,  it 
ought  not  to  receive  any  accession  of  fibres  from 
them,  and  such,  according  to  the  writer's 
experience,  is  the  case.  As  it  emerges  from 
the  pons,  the  lesser  packet  receives  an  epithe- 
lium from  its  surface;  but  he  has  not  been 
able  to  detect  any  fibres  originating  within  the 
substance  of  that  part. 

The  structural  arrangement,  which  the  ence- 

*  Op.  cit. 


phalic  portion  of  the  nerve  presents  within  the 
brain,  is  different  from  that,  for  which  it  is- 
remarkable,  while  superficial  to  it.  Exter- 
nally it  is,  as  has  been  stated,  of  a  fascicular 
texture;  but,  within,  that  appearance  is  not  to 
be  observed :  there  the  larger  portion  is  a 
white,  soft,  homogeneous,  flattened  cord,  the 
delicacy  of  which,  in  the  natural  state,  forbids 
the  separation  of  it  into  distinct  parts ;  but 
when  sufficiently  hardened,  it  may  be  divided 
into  numerous  thin  strata,  and  these  again  into 
delicate  fibrils.  That  such  an  arrangement  is 
a  natural,  and  not  an  artificial  appearance,  is 
manifest  from  the  circumstance,  that  the  sepa- 
ration into  fibrils  can  be  effected  only  in  one 
direction,  the  length  of  the  nerve,  and  that 
they  break  off  when  it  is  attempted  in  the 
other.  The  nerve  retains  those  characters  as 
far  as  its  attachment  behind  the  crus,  but  there 
they  cease ;  the  pure  white  colour  suddenly 
disappears ;  the  point  of  attachment  and  the 
cords  descending  from  it  present  a  cineritious 
tint ;  and  they  are  not  absolutely  distinct  from 
the  surrounding  substance,  as  the  nerve  had 
previously  been,  but  immersed  in  it ;  they  are, 
however,  still  manifestly  composed  of  fila- 
ments, which  may  be  rent  either  toward  or 
from  the  point  of  attachment ;  and  after  im- 
mersion in  spirit  they  become  nearly  white. 
The  course  of  the  nerve,  from  its  attachment 
to  the  surface  of  the  brain,  is  forward  and  out- 
ward toward  the  internal  anterior  extremity  of 
the  petrous  portion  of  the  temporal  bone  ;  it 
next  passes  over  the  superior  margin  of  that 
portion,  and  descends  upon  its  anterior  surface 
into  the  middle  fossa  of  the  base  of  the  cra- 
nium, where  it  reaches  the  Gasserian  ganglion. 
During  its  short  course,  from  its  attachment  to 
the  brain,  to  the  ganglion,  it  is  at  first  contained 
within  the  proper  cerebral  cavity,  by  the  side 
of  the  pons  Varolii,  and  beneath  the  internal 
anterior  angle  of  the  tentorium  cerebelli  ;  in 
the  second  place,  in  the  middle  fossa,  it  is 
not  within  the  cerebral  cavity  of  the  cranium, 
but  beneath  it,  separated  fro  n  it  by  a  lamina 
of  dura  mater;  it  is  there  contained  in  a  canal 
or  chamber,  formed  by  a  separation  of  the 
dura  mater  into  two  layers,  between  which  the 
nerve  and  its  ganglion  are  inclosed,  one  be- 
neath them  attached  to  the  bone,  another  above 
separating  thein  from  the  brain.  This  chamber 
is  situate  immediately  external  to,  and  lower 
than  the  cavernous  sinus,  but  separated  from 
it  by  the  inferior  lamina  of  the  dura  mater  just 
described,  which  ascends  from  the  bone  to 
join  the  superior,  and  in  so  doing  forms  a 
septum  between  the  two  chambers  ;  it  is  about 
three-fourths  of  an  inch  long,  reaching  from 
the  superior  margin  of  the  petrous  bone  to  the 
anterior  margin  of  the  depression  upon  its 
anterior  surface,  in  which  the  ganglion  rests. 
In  front  this  chamber  is  wide,  containing  at  that 
part  the  ganglion,  and  sends  fibrous  offsets  upon 
the  nervous  trunks  proceeding  from  it;  poste- 
riorly it  is  narrow,  and  presents  an  oval  aperture, 
about  one-third  of  an  inch  long,  situate  ex- 
ternal and  inferior  to  the  posterior  clinoid  pro- 
cess of  the  sphenoid  bone  beneath  the  attach- 
ment of  the  tentorium  cerebelli  to  that  process, 


278 


FIFTH  PAIR  OF  NERVES. 


and  also  beneath  the  superior  petrous  sinus  : 
by  this  aperture  the  chamber  communicates 
with  the  cerebral  cavity  and  the  nerve  enters. 
The  chamber  is  lined  by  the  arachnoid  mem- 
brane, as  far  as  the  posterior  margin  of  the  gan- 
glion, but  along  this  the  membrane  is  reflected 
from  the  interior  of  the  chamber  to  the  nerve, 
and  returns  upon  it  into  the  cranium :  hence 
the  nerve  is  free  within  the  chamber,  while 
the  dura  mater  is  attached  to  the  surfaces  of 
tlie  ganglion,  and  so  closely  that  it  requires 
care  to  separate  it  from  them.  The  cham- 
ber presents  a  remarkable  variety  in  its  con- 
struction in  some  animals:  in  the  horse,  for 
instance,  its  parietes  are  not  simply  fibrous, 
as  in  man,  but,  frequently  at  least,  in  great 
part  osseous,  being  at  the  same  time  lined  by 
the  membrane. 

The  passage  of  the  nerve  over  the  margin 
of  the  petrous  bone  is  marked  by  an  inter- 
ruption in  the  sharp  edge,  which  the  bone 
presents  external  to  that  point,  and  its  site 
upon  its  anterior  surface,  as  also  that  of  the 
ganglion  by  a  corresponding  shallow  depres- 
sion. 

Throughout  the  course  of  this  portion  of 
the  nerve,  the  relation  of  the  two  packets 
to  each  other  varies  ;  at  the  attachment  of  the 
nerve  to  the  crus  cerebelli,  the  smaller  packet, 
allowance  being  made  for  those  vaiieties  pre- 
sented by  it  in  its  mode  of  attachment,  is 
superior  and  internal  to  the  larger;  in  the  in- 
terval between  the  crus  and  the  margin  of  the 
petrous  bone,  the  smaller  packet  gradually 
descends  along  the  inner  side  of  the  larger, 
until  it  has  reached  the  same  level,  so  that  the 
two  packets  are  placed  immediately  side  by 
side  upon  the  margin  of  the  bone,  the  lesser 
internal  to  the  greater;  but  as  the  nerve  pro- 
ceeds into  the  middle  fossa,  the  smaller,  at 
the  same  time,  passes  from  within  outward 
beneath  the  larger,  and  also  beneath  the  gan- 
glion, toward  its  outer  and  posterior  extremity; 
during  this  course  it  has  no  communication 
with  the  ganglion,  but  is  quite  distinct  from 
it,  though  inclosed  in  common  in  the  chamber 
formed  by  the  dura  mater,  and  connected  with 
it  by  a  dense  cellular  or  fibrous  structure;  but 
having  thus  passed  the  ganglion,  the  lesser 
packet  is  united  to  the  third  trunk  proceeding 
from  that  body,  and  with  it  constitutes  the  third 
division  of  the  nerve. 

The  larger  packet,  on  the  contrary,  is  at- 
tached to  the  ganglion.  It  has  been  before 
stated  that  the  plexiform  arrangement,  which 
it  presents,  becomes  less,  as  it  approaches  that 
body;  its  fasciculi  become  more  distinct;  they 
separate  from  each  other,  so  that  the  width  of 
the  packet  is  greatly  increased,  and  having 
rea  hed  the  posterior  margin  of  the  ganglion 
they  are  received  into  the  channel  which  it 
presents;  in  which  they  are  ranged,  in  series, 
from  one  extremity  of  the  body  to  the  other, 
overlapped  by  its  edges,  and  enter  abruptly  into 
the  substance  of  the  ganglion. 

External  portion  of  the  nerve. — The  external 
orperipheric  portion  of  the  nerve  consists  of  three 
large  trunks  or  divisions,  which  are  connected, 
on  the  one  hand  by  their  ramifications,  with  the 


organs  to  which  the  nerve  is  distributed,  and 
on  the  other,  with  the  ganglion  and  the  brain. 
They  are  distributed,  generally  speaking,  to 
three  different  regions  of  the  head  and  face, 
one  to  the  uppermost,  another  to  the  middle 
or  superior  maxillary,  and  the  third  to  the 
lowest  or  inferior  maxillary  regions,  and  they 
are  denominated,  either  numerically,  first, 
second,  and  third,  as  by  the  first  Meckel;  or, 
according  to  the  parts  to  which  they  are  dis- 
tributed, the  first  the  ophthalmic,  by  Willis; 
the  second  the  superior  maxillary,  and  the 
third  the  inferior  maxillary,  by  Winslow. 
These  methods  of  distinction  have  their  several 
advantages.  Could  we  select  names  which 
would  give  adequate  ideas  of  the  distribution 
of  the  trunks,  the  latter  would  certainly  be 
preferable;  but  inasmuch  as  those  which  have 
been  selected  do  not  at  all  adequately  express 
that  distribution,  and  are  attended,  therefore, 
with  the  inconvenience  of  riot  giving  a  suffi- 
ciently enlarged  idea  thereof,  it  would  probably 
have  been  better,  had  the  former  been  from 
the  first  adopted  and  adhered  to,  for  such 
names  could  not  create  any  incorrect  impression 
with  regard  to  the  distribution  of  the  several 
divisions  of  the  nerve ;  in  fact,  the  epithets 
ophthalmic,  superior,  and  inferior  maxillaries 
ought  to  be  altogether  discarded,  for,  beside 
the  objection  to  their  use  already  stated,  it  will 
be  found,  upon  reference  to  the  anatomy  of 
other  animals,  that  they  are  by  no  means  dis- 
tinctly appropriate,  and  that  the  circumstances 
upon  which  they  are  founded  are  purely  inci- 
dental, associated  with  the  peculiarities  of  the 
animal ;  for  the  proof  of  which,  see  the  com- 
parative disposition  of  the  fifth  nerve  in  the 
several  classes. 

The  three  trunks  differ  from  each  other  in 
size.  The  first,  the  ophthalmic,  is  the  smallest; 
the  second,  the  superior  maxillary,  is  inter- 
mediate in  size ;  and  the  third,  the  inferior 
maxillary,  is  by  much  the  largest.  They  are 
connected  to  the  anterior  convex  margin  of  the 
ganglion, — the  first  to  its  superior  internal 
extremity,  the  second  to  its  middle,  and  the 
third  to  its  inferior  external  extremity.  At  their 
attachment  they  are  wide,  flattened,  and  of  a 
cineritious  tint;  but  as  they  proceed  they 
become  contracted  in  width,  cylindrical  or  oval 
in  form,  and  of  a  white  colour.  Their  texture 
is  fascicular  and  compact,  the  fasciculi  of  which 
they  are  composed  being  bound  up  closely 
together,  and  they  differ  remarkably  in  com- 
position, the  two  first,  the  ophthalmic  and 
superior  maxillary,  being  derived  altogether 
from  the  ganglion,  and  thus  being,  in  anato- 
mical constitution,  simple ;  whereas  the  third 
is  composed  of  two  parts,  one  derived  from 
the  ganglion,  and  another  formed  by  the  lesser 
packet  of  the  nerve,  which  does  not  join  that 
body,  and  hence  that  division  is  compound. 

The  trunks  rest  partly  against  the  outer  side 
of  the  cavernous  sinus  and  in  part  upon  the 
base  of  the  cranium  in  its  middle  fossa,  and 
they  are  enclosed  in  offsets  from  the  fibrous 
chamber,  in  which  the  ganglion  is  contained. 
Their  relative  position  corresponds  to  the  posi- 
tion of  the  ganglion ;  the  first  is  superior  and 


FIFTH  PAIR  OF  NERVES. 


279 


internal  to  the  other  two,  the  second  is  inferior 
and  external  to  the  first,  and  the  third  is  exter- 
nal, posterior,  and  inferior  to  both  the  others. 
They  go  off  from  the  ganglion  at  different 
inclinations,  the  first  forward  and  slightly 
upward,  the  second  directly  forward,  and  the 
third  almost  directly  downward ;  hence  the 
first  and  second  form  a  very  acute  angle  with 
each  other,  while  that  between  the  second  and 
third  is  much  greater. 

First  or  ophthalmic  division. — This  division 
is  distributed  to  the  eye  and  its  appendages, 
to  the  nostril,  and  to  the  forehead.  It  is  the 
smallest  of  the  three  trunks  proceeding  from 
the  ganglion,  and  is  situate  superior  and  inter- 
nal to  the  other  two.  It  is  about  three-fourths 
of  an  inch  long  from  the  ganglion  to  its  division 
into  branches,  and  is  contained  thus  far  within 
the  cranium.  Its  course  is  forward,  upward, 
and  slightly  outward  toward  the  upper  part  of 
the  foramen  lacerum  of  the  orbit.  It  is  laid 
against  the  outer  side  of  the  cavernous  sinus, 
in  company  with  the  third  and  fourth  nerves, 
and  is  contained  in  the  external  wall  of  the 
sinus,  being  separated  from  the  interior  of  that 
chamber  by  a  thin  septum,  which  is  a  prolon- 
gation of  the  inferior  internal  wall  of  the  canal 
in  which  the  nerve  and  ganglion  are  contained. 
The  septum  is  dense,  but  at  the  same  time  so 
thin  and  transparent  that  the  nerve  can  be  seen 
through  it  from  the  side  of  the  sinus,  while  the 
lamina  of  the  dura  mater,  by  which  it  is  sepa- 
rated from  the  interior  of  the  cranium,  is  so 
thick  and  opaque,  that  the  course  of  the  nerve 
is  a'together  concealed  from  that  side.  At  its 
outset  the  nerve  is  beneath,  and  external  to  the 
third  and  fourth  nerves,  and  external  and  some- 
what superior  to  the  sixth,  which  is  within  the 
sinus;  but  ascending  as  it  proceeds,  it  gains, 
about  the  middle  of  the  sinus,  the  same  level 
with  the  third,  placed  still  at  its  outer  side, 
and  inferior  to  the  fourth,  and  then  terminates 
by  dividing  into  branches. 

Presently  after  its  origin  from  the.  ganglion 
the  nerve  is  joined  by  one  or  more  very  fine 
filaments  from  the  sympathetic :  this  is  ex- 
pressly denied  by  the  first  Meckel,  but  he  was 
certainly  mistaken;  they  are  very  faithfully 
represented  by  Arnold.  In  order  to  display 
them  the  sixth  nerve  may  be  separated  carefully 
from  the  carotid  artery  in  the  cavernous  sinus, 
after  which  it  will  be  found  that  branches  of 
the  sympathetic  ascend  upon  the  artery  internal 
to  that  nerve,  and  distinct  from  those  which 
are  connected  with  it.  Having  surmounted  it 
they  branch  off,  some  upon  the  artery  as  it 
passes  to  the  brain,  others  to  other  destinations, 
and  of  the  latter  some  incline  outward  above 
the  sixth  nerve  and  are  connected  to  the  first 
division  of  the  fifth:  they  are  short  and  very 
delicate. 

The  first  division  of  the  fifth  gives  off  no 
branch  from  its  outset  to  its  final  division, 
except  an  extraordinary  filament  described  by 
Arnold,  and  denominated  by  him  the  recurrent 
branch  of  the  first  division  of  the  fifth.  It  arises 
from  the  upper  side  of  the  trunk  immediately 
after  it  leaves  the  ganglion,  runs  backward  above 
this  body  at  a  very  acute  angle,  enters  the  struc- 


ture of  the  tentorium  cerebelli,  and  divides  be- 
tween its  laminae  into  several  very  delicate  fila- 
ments. 

The  branches  into  which  the  first  division  of 
the  fifth  ultimately  divides  are  either  two  orthree; 
according  to  the  elder  Meckel  and  the  greater 
number  of  authorities  they  are  three;  according 
to  others  they  are  sometimes  three,  but  are  more 
frequently  only  two.  The  three  branches  are 
the  frontal,  the  nasal,  and  the  lachrymal. 
When  the  branches  are  but  two,  they  are, 
according  to  J.  F.  Meckel,  the  nasal  and  the 
frontal,  the  latter  in  such  case  giving  off  that, 
which  in  the  other  mode  of  distribution  is  the 
third, the  lachrymal.  Theelder  Meckel  attributes 
the  difference  of  opinion  which  prevails  with  re- 
gard to  this  point  to  the  fact  that  the  lachrymal 
nerve  frequently  has  a  second  root  derived 
from  the  frontal,  which  in  such  cases  has  been 
assumed  to  be  the  origin  of  the  nerve.  The 
names  which  have  been  applied  to  those 
branches  have  been  taken  either  from  their 
destination  or  from  their  relative  course ;  thus 
the  frontal,  so  called  from  its  distribution  to 
the  forehead,  is  also  called  the  superior  or 
middle  branch;  the  nasal,  so  called  because 
finally  distributed  to  the  nostril,  the  internal 
or  inferior,  and  the  lachrymal,  which  derives 
its  name  from  the  'achrymal  gland,  the  external. 
The  three  branches  differ  in  size;  the  frontal  is 
considerably  larger  than  either  of  the  others, 
the  nasal  is  second,  and  the  lachrymal  is  much 
the  smallest.  They  all  three  traverse  the  orbit, 
but  they  pursue  different  routes,  and  have,  at 
entering,  very  different  relations. 

1.  The  frontal  tierve  appears  in  the  human 
subject,  both  from  its  size  and  itsdirection,  to  be 
the  continuation  of  the  original  trunk.  In  other 
animals,  however,  it  is  otherwise:  in  them  the 
predominance  of  the  frontal  nerve  diminishes 
along  with  that  of  the  superior  region  of  the 
face,  until  in  some  it  ceases  to  exist  as  a  pri- 
mary branch  of  the  first  division  of  the  fifth, 
and  its  place  is  supplied  by  a  secondary  branch 
of  another,  while  the  nasal  branch  increases 
in  the  same  proportion,  and  seems  ultimately 
to  constitute  itself  the  first  division  of  the  fifth.* 
The  frontal  nerve  passes  upward  and  forward 
toward  the  highest  part  of  the  forameii  1  ice  rum 
of  the  orbit,  and  enters  that  region  through  it. 
It  then  continues  its  course  through  the  orbit, 
to  the  superciliary  foramen  and  escapes  through 
it  to  the  forehead.  During  this  course  it  is. 
placed,  before  it  has  entered  the  orbit,  at  the 
outer  side  of  the  third  nerve ;  it  then  rises 
above  the  third  and  crosses  over  it  to  its  inner 
side.  In  doing  so  it  is  accompanied  by  the 
fourth  nerve,  to  which  it  is  external  and  in- 
ferior; it  enters  the  orbit  in  company  with 
the  fourth  and  nearly  on  the  same  level,  but 
still  external  to  and  somewhat  beneath  it.  In 
entering,  it  passes  above  the  origin  of  the 
superior  rectus  muscle,  and  all  the  other  pans 
transmitted  through  the  foramen  lacerum,  with 
the  exception  of  the  fourth  nerve.  At  the  en-, 
trance  of  the  frontal  nerve  into  the  orbit  and 
during  its  course  from  its  origin  thereto  it  is 

*  See  comparative  distribution  of  the  fifth  rieive, 


280 


FIFTH  PAIR  OF  NERVES. 


closely  attached  to  the  fourth  nerve,  but  pre- 
sently after  separates  from  it,  the  fourth  in- 
clining inward,  is  continued  forward  to  the 
superciliary  foramen,  lying  upon  the  superior 
surface  of  the  superior  rectus  and  levator  palpe- 
bral muscles,  being  through  its  whole  course 
within  the  orbit  immediately  beneath  its  roof. 
Having  reached  the  foramen  it  passes  through 
it,  and  changing  its  direction,  ascends  round 
the  superciliary  arch,  upon  the  forehead,  be- 
neath the  orbicularis  palpebrarum  and  frontalis 
muscles,  and  is  thenceforth  called  by  some  the 
external  frontal  nerve  in  contradistinction  to  a 
branch  from  itself,  the  supra-trochlear,or  internal 
frontal.  In  its  mode  of  escape  from  the  orbit 
the  frontal  nerve  is  subject  to  some  variety, 
consequent  in  part  upon  the  mode  in  which 
the  superciliary  foramen  is  formed,  that  being 
in  some  instances  altogether  osseous,  in  others 
osseous  only  at  its  superior  part  and  completed 
by  ligament  below;  in  this  case  the  nerve 
escapes  through  an  osseous  notch,  and  not  a 
foramen.  In  other  instances,  again,  when  the 
nerve  divides  previous  to  its  escape  it  is  some- 
times transmitted  through  two  apertures. 

The  distribution  of  the  frontal  nerve,  as  well 
as  that  of  most  of  the  secondary  branches,  is 
subject  to  varieties,  which  the  author  has  en- 
deavoured to  embrace  in  the  following  account. 
In  the  first  place  the  frontal,  at  its  entrance 
into  the  orbit,  anastomoses  with  the  fourth 
nerve.  Next  it  gives  off,  some  time  after  its 
entrance  and  previous  to  its  division,  a  long  and 
slender  branch,  which  runs  forward  and  inward 
toward  the  trochlea  of  the  superior  oblique. 
Then  it  divides  into  two  branches,  a  larger 
one,  the  continuation  of  the  nerve,  which 
escapes  through  the  superciliary  foramen,  and 
a  smaller,  the  supra-trochleur  or  internal 
frontal.  The  latter  passes  forward  and  at  the 
same  time  inward  toward  the  trochlea  of  the 
oblique  muscle,  escapes  from  the  orbit  internal 
to  the  continued  trunk  of  the  frontal  nerve, 
and  ascending  upon  the  forehead  beneath  the 
coirugator  supercilii,  orbicularis,  and  frontalis 
musc'es,  it  has  received  the  name  of  internal 
frontal,  in  contradistinction  to  the  continued 
trunk,  which  is  at  the  same  time  called  external 
frontal.  The  point  at  which  the  frontal  divides 
is  variable;  for  the  most  part  the  division  takes 
place  about  midway  in  the  orbit.  In  some 
instances  it  occurs  before  the  nerve  has  reached 
that  point,  and  in  others,  again,  not  until  it 
has  approached  nearer  to  the  anterior  margin  of 
the  orbit.  The  distance  of  the  division  from 
the  margin  of  the  orbit  appears  to  modify  the 
course  of  the  internal  branch :  when  it  is  far 
back,  the  nerve  escapes  from  the  orbit  above 
the  trochlea,  and  hence  the  name  supra-tro- 
chlear,  given  to  it  by  Meckel ;  and  when  near  the 
margin  it  escapes  external  to  the  trochlea,  be- 
tween it  and  the  superciliary  foramen  ;  while  in 
the  latter  case  a  branch  of  the  nerve  is  transmitted 
above  the  trochlea,  in  the  usual  course  of  the 
nerve  itself.  Nor  is  the  size  of  the  two  branches 
into  which  the  frontal  divides  equal  or  uni- 
form ;  for  the  most  part  the  external  branch  is 
the  larger,  but  in  some  instances  the  two  are 
of  equal  size.    In  its  course  forward  the  supra- 


trochlear nerve  gives  off  first,  occasionally  a 
delicate  branch,  which  frequently  arises  from 
the  frontal  itself  prior  to  its  division,  the  course 
and  destination  of  which  have  been  already 
described.  Next  it  gives  off,  in  some  instances 
before,  in  others  not  till  after  it  has  escaped 
from  the  orbit,  a  branch  which  passes  inward 
toward  the  internal  canthus,  and,  uniting  with 
either  the  infra-trochlear  itself  or  a  branch  of 
it,  concurs  in  forming  a  small  plexus,  from 
which  filaments  are  distributed  to  the  structures 
of  the  upper  eyelid,  toward  its  internal  part, 
and  to  the  eyebrow.  Having  escaped  from 
the  orbit,  the  supra-trochlear  nerve  divides  into 
two  sets  of  branches,  denominated  palpebral 
and  frontal ;  the  first  descend  into  the  superior 
eyelid,  and  are  distributed  to  the  structures  of 
that  part ;  the  filaments  communicating  exter- 
nally with  those  of  the  frontal,  and  internally 
with  those  of  the  infra-trochlear.  The  frontal 
branches  ascend  round  the  superciliary  arch, 
beneath  the  orbicularis  palpebrarum  and  the 
coirugator  supercilii  muscles,  upon  the  fore- 
head, and  these  are  disposed  of  in  a  manner 
similar  to  that  in  which  the  branches  of  the 
proper  or  external  frontal  are.  Some  are  dis- 
tributed to  the  orbicularis,  corrugator,  and  fron- 
talis muscles ;  other,  long  branches,  ascend 
beneath  the  frontalis,  traverse  it,  and  become 
subcutaneous,  and  are  distributed  to  the  inte- 
guments of  the  scalp  upon  the  forehead.  Of 
these  the  external  unites  with  the  internal 
branch  of  the  external  frontal,  and  forms  with 
it  a  common  branch,  which  has  the  same 
destination  as  the  others. 

The  external  larger  branch  of  the  frontal, 
called,  in  contrast  with  the  last,  the  external 
frontal  nerve,  also  divides  into  two  sets  of 
branches,  palpebral  and  frontal. 

The  nerve  in  some  instances  emerges  from 
the  orbit  a  single  trunk,  in  others  it  divides  be- 
fore it  escapes  from  that  region,  for  the  most 
part  into  two  branches,  which  are  transmitted 
sometimes  through  the  same,  at  others  through 
distinct  apertures,  and  from  which  the  several 
ramifications  arise,  they  themselves  becoming 
ultimately  the  long  frontal  branches. 

Immediately  after  their  escape  the  frontal 
branches  give  off  externally  slender  filaments, 
which  run  outward  toward  the  external  can- 
thus,  one  beneath  the  eyebrow,  through  the 
upper  eyelid,  and  one  or  more  through  the 
brow  itself;  these  ramify  as  they  proceed,  sup- 
ply the  lid  and  brow  at  their  outer  part,  and 
anastomose  with  filaments  of  the  portio  dura, 
and  of  the  superficial  temporal  nerve. 

The  frontal  branches  are  arranged  into  super- 
ficial and  deep ;  those  epithets  have  been  diffe- 
rently applied  by  different  writers ;  thus  those 
which  the  elder  Meckel  terms  the  superficial, 
Boyer  and  Cloquet  denominate  the  deep 
branches  ;  nor  is  this  to  be  wondered  at,  inas- 
much as  both  sets  become  ultimately  superficial ; 
it  were  better,  perhaps,  to  arrange  them  into 
short  and  long  branches.  The  short  branches 
are  distributed  to  the  orbicularis  muscle,  the 
corrugator,  and  the  frontalis,  and  having  sup- 
plied those  muscles,  they  or  others  of  them  be- 
come subcutaneous,  and  terminate  in  the  inte- 


FIFTH  PAIR  OF  NERVES. 


281 


guments  of  the  eyebrow  and  forehead  :  one 
of  these  branches,  as  described  by  Meckel, 
runs  outward,  through  the  orbicularis,  toward 
the  external  canthus,  and  establishes  anasto- 
moses with  filaments  of  the  facial  portio  dura 
nerve.  The  long  branches  are  two,  an  external 
and  an  internal ;  of  those  the  external  is,  for 
the  most  part,  the  larger  ;  they  ascend  beneath 
the  frontalis  and  the  frontal  aponeurosis,  the 
former  inclining  outward,  the  latter  inward,  as 
they  ascend ;  they  distribute  in  their  course 
ramifications  to  the  muscle,  and  to  the  deeper 
structures  of  the  scalp,  as  well  as  some- 
times, according  to  Meckel,  to  the  pericra- 
nium, and  traversing  the  frontal  aponeurosis, 
they  become  subcutaneous,  and  terminate  in 
the  structure  and  integument  of  the  scalp.  The 
external  communicates  with  the  superficial 
temporal  nerves  ;  the  internal  with  the  internal 
frontal,  the  supra-trochlear.  They  are  said  both 
to  anastomose  with  the  branches  of  the  sub- 
occipital nerve ;  but  Meckel  states  that  he 
has  pursued  them  until  they  have  escaped 
his  sight,  and  yet  he  could  not  discover  any 
anastomoses  between  them  and  the  branches  of 
that  nerve. 

2.  The  nasal  nerve  is  in  size  the  second 
branch  of  the  first  division  of  the  fifth,  and  arises 
always  separately  from  the  original  trunk.  Its 
course  is  inferior  and  internal  to  those  of  the 
other  two,  and  hence  the  nerve  is  called  by 
some  the  inferior,  by  others  the  internal  branch. 
It  is  distributed  partly  to  the  eye  and  its  appen- 
dages and  partly  to  the  nostril,  and  hence  it  is 
also  called  naso-ocular  by  Scemmerring.  The 
direction  of  its  course  is  forward  and  very 
much  inward;  it  passes  through  the  foramen 
lacerum  into  the  orbit ;  then  traverses  that  re- 
gion from  without  inward  toward  its  internal 
wall,  and  having  reached  it  at  the  foramen  or- 
bitarium  internum  anterius,  it  escapes  from  the 
orbit  through  that  foramen,  and  passes  into  the 
cranium ;  it  emerges  into  the  cranium  from 
beneath  the  margin  of  the  orbitar  process  of  the 
frontal  bone,  and  crosses  the  cribriform  plate  of 
the  ethmoid  obliquely  forward  and  inward, 
contained  in  a  channel  in  the  bone,  and  in- 
vested by  the  dura  mater,  until  it  reaches  the 
crista  gal  1  i ;  it  then  descends  from  the  cranium 
into  the  nostril,  through  the  cleft,  which  exists 
at  either  side  of  the  crista  galli  at  the  anterior 
part  of  the  cribriform  plate,  and  having  reached 
the  roof  of  the  nostril,  it  divides  into  its  final 
branches.* 

The  nasal  branch  is  concealed  at  its  origin 
by  the  frontal,  which  is  situate  external  and 
superior  to  it.  Before  its  entrance  into  the  orbit 
it  is  placed  by  the  outer  side  of  and  closely  ap- 
plied to  the  third  nerve.    In  entering  the  orbit 

*  The  nasal  is  usually  described  as  terminating 
by  dividing  within  the  orbit  into  two  branches,  the 
ethmoidal  or  internal  nasal,  and  the  infra-trochlear  or 
external  nasal :  the  author  has  preferred  considering 
the  former  as  the  continuation  of  the  nerve,  be- 
cause in  inferior  animals  both  the  nasal  is  the  prin- 
cipal portion  of  the  first  division  of  the  fifth,  or 
alone  constitutes  it',  and  it  is  manifestly  prolonged, 
as  such,  into  the  nostril  and  the  beak.  See  Com- 
parative Distribution, 


it  passes  between  the  two.posterior  attachments 
of  the  external  rectus  muscle,  in  company  with 
the  third  and  sixth  nerves,  external  to  the 
former  and  between  its  two  divisions,  and 
internal  and  somewhat  superior  to  the  latter. 
In  its  course  across  the  orbit  the  nasal  nerve 
passes  above  the  optic  nerve,  immersed  in  fat, 
and  accompanied   by  the  ophthalmic  artery, 
being  at  the  same  time  beneath  the  levator 
palpebral,  ihe  superior  oblique,  and  superior 
rectus  muscles,    and    in  crossing    the  optic 
nerve,  it  is  placed  between  it  and  the  last 
mentioned  muscle.    Through  the  foramen  or- 
bitarium  the  nerve  is  accompanied  by  the  an- 
terior ethmoidal  artery,  and  within  the  cra- 
nium is  situate  beneath   but  not  in  contact 
with  the  olfactory  bulb,  being  separated  from 
it  by  the  dura  mater.    The  course  of  the  nerve 
from  the  orbit  to  the  nostril  is  liable  to  be 
modified  by  the  developement  of  the  frontal 
sinuses  ;  when  they  are  very  large,  and  extend, 
as  they  not  unfrequently  do,  into  the  orbitar 
processes  of  the  frontal  bone  and  the  horizontal 
plate  of  the  ethmoid,  the  nerve  may  cross  to 
the  side  of  the  crista  galli  without  entering  the 
cranium,  being  contained  in  a  lamella  of  the 
ethmoidal  bone.     The  nasal  branch,  before 
entering  the  orbit,  receives,  according  to  Bock, 
J.  F.  Meckel,  and  Cloquet,  a  filament  from 
the  sympathetic.  The  branches  which  the  nasal 
gives  ofT,  are  the  lenticular,  the  ciliary,  the 
infra-trochlear,  and  the  nasal. 

The  lenticular  branch  is  given  off  as  the  nasal 
enters  the  orbit,  and  on  the  outer  side  of  the 
optic  nerve;  it  is  a  delicate  branch,  about  half 
an  inch  long;  it  first  anastomoses  with  the  supe- 
rior division  of  the  third  nerve ;  then  inns  for- 
ward along  the  outer  side  of  the  optic  nerve, 
and  terminates  by  joining  the  superior  and  pos- 
terior part  of  the  lenticular  ganglion.  Accord- 
ing to  Bock  and  Meckel  junior,  it  occasionally 
gives  off  a  ciliary  nerve,  and  according  to 
Meckel  senior  it  is,  in  rare  instances,  derived 
from  the  third  nerve.  To  the  latter  statement, 
however,  the  author  hesitates  to  assent :  it  ap- 
pears to  him,  that  it  should  rather  be  said  in 
such  cases  to  be  wanting. 

The  ophthalmic,  lenticular  or  ciliary  ganglion, 
according  to  Cloquet,  is  of  an  oblong  form — 
its  greater  length  from  behind  forward ;  it  is 
one  of  the  smallest  ganglia  of  the  body, 
being,  however,  variable  in  size ;  its  colour  is 
reddish,  at  times  white  ;  it  exists  constantly  in 
the  human  subject :  it  is  situate  between  the 
external  rectus  muscle  and  the  optic  nerve,  laid 
against  the  outer  side  of  the  nerve,  at  a  little 
distance  from  its  entrance  into  the  orbit ;  its 
external  surface  convex,  corresponding  to  the 
muscle  ;  its  internal,  concave,  to  the  nerve  ;  to 
its  superior  posterior  angle  is  attached  the  len- 
ticular twig  of  the  nasal  branch  of  the  first 
division  of  the  fifth  ;  this  filament  constituting 
its  long  root ;  to  its  inferior  posterior  angle  a 
filament  from  the  inferior  division  of  the  third 
nerve  is  attached,  constituting  its  short  root. 
To  the  posterior  part  of  the  ganglion  are  also 
attached  two  filaments  derived,  one  from  the 
cavernous  ganglion  or  the  carotid  plexus  ;  the 
other,  the  constant  existence  of  which  has  not 


282 


FIFTH  PAIR  OF  NERVES. 


been  yet  established,  from  the  sphenopalatine 
ganglion. 

The  ganglion  gives  off  from  its  anterior  ex- 
tremity a  considerable  number  of  very  delicate 
filaments,  denominated  from  their  distribution 
ciliary  :  they  amount  to  from  twelve  to  sixteen ; 
are  reddish  and  tortuous;  and  run  forward 
along  the  optic  nerve  to  the  back  of  the  eye, 
which  they  enter  at  a  short  distance  from  the 
nerve.  They  are  distinguished  into  two  fasci- 
culi, superior  and  inferior ;  which  are  attached, 
one  to  the  superior  anterior,  the  other  to  the 
inferior  anterior  angles  of  the  ganglion :  the 
former  is  the  smaller ;  contains  at  first  but  three 
filaments,  which,  as  they  proceed,  divide  so  as 
to  produce  six,  and  run  parallel  to  each  other 
above  the  optic  nerve:  the  second  fasciculus  is 
situate  on  the  outside  of  and  beneath  the  optic 
nerve,  and  contains  from  six  to  ten  filaments  col- 
lected at  their  origin  into  six  branches :  they  pass 
beneath  the  nerve  and  incline  inward,  so  as 
to  gain,  some  of  them,  its  inner  side  :  one  of 
them  runs  outward  and  joins  one  of  the  ciliary 
branches  of  the  nasal  nerve.  The  ciliary  nerves 
all  penetrate  the  sclerotic  coat  of  the  eye  sepa- 
rately and  obliquely  ;  then  run  forward  between 
the  sclerotic  and  choroid  coats,  without  giving 
filaments  to  either,  lodged  in  channels  upon 
the  inner  surface  of  the  former:,  as  they  ap- 
proach the  ciliary  circle  they  divide,  each  into 
two  or  three  filaments,  which  enter  the  circle 
and  are  lost  in  it :  some  of  them  pierce  the 
choroid  at  the  anterior  part  of  the  eye,  and  go 
to  the  ciliary  processes. 

The  ciliary  branches  are  two  or  three  in 
number ;  they  are  very  delicate,  and  are  given 
off,  while  the  nasal  is  crossing  the  optic  nerve  ; 
they  run  forward  along  the  optic,  imbedded  in 
fat,  penetrate  the  sclerotic  coat  of  the  eye  pos- 
teriorly, and  then  continue  forward  between 
the  sclerotic  and  choroid  coats,  in  like  manner 
as  the  other  ciliary  nerves,  to  the  ciliary  circle. 

The  infra-trochlear  brunch,  so  called  by  the 
elder  Meckel,  because  it  escapes  from  the 
orbit  beneath  the  trochlea  of  the  oblique  mus- 
cle, is  also  called  external  nasal.  It  is  given 
off  when  the  nasal  has  reached  the  inner  wall 
of  the  orbit,  and  as  it  is  about  to  enter  the  fora- 
men orbitarium  ;  it  is  a  branch  comparatively 
considerable,  at  times  longer,  at  others  smaller 
decidedly  than  the  continuation  of  the  nasal ; 
it  runs  directly  forward  along  the  inner  wall, 
beneath  the  superior  oblique  muscle,  toward 
its  trochlea,  and  having  reached  that,  escapes 
from  the  orbit  beneath  it.  It  then  divides,  in 
the  internal  canthus  of  the  eye,  into  two 
branches,  a  superior  and  an  inferior. 

The  infra-trochlear,  while  within  the  orbit, 
gives  off  occasionally,  soon  after  its  origin, 
a  small  branch,  which  returns  and  joins  the 
nasal  before  it  enters  the  foramen  orbitarium  ;* 
also  a  delicate  branch,  which  joins  a  corre- 
sponding branch  given  off  either  by  the  supra- 
trochlear or  the  frontal.  The  distribution  of  the 
nerve  resulting  from  their  junction  has  been 
already  described  under  the  frontal  nerve.  Of 
its  ultimate  branches,  the  superior  joins  and 


forms  a  plexus  with  a  branch  of  the  supra-tro- 
chlear  nerve,  already  described,  given  off  either 
immediately  before  or  after  that  nerve  has 
escaped  from  the  orbit.  From  the  junction  of 
the  two,  numerous  delicate  ramifications  are 
distributed  to  the  upper  eyelid  and  to  the  eye- 
brow. The  inferiorgives  off  several  ramifications, 
which  are  distributed  to  the  origin  of  the  cor- 
rugator,  the  orbicularis,  and  the  pyramidalis 
nasi  muscles  ;  to  the  conjunctiva,  at  the  inter- 
nal canthus  ;  the  carunculalachrymalis  and  the 
lachrymal  sac.  Of  those  ramifications,  one  de- 
scends before  the  tendon  of  the  orbicularis,  and 
communicates  with  a  branch  of  the  portio 
dura:  another  communicates  with  a  branch  of 
the  infra-orbital;  but  the  latter  anastomosis  is 
uncertain.* 

The  nasal  nerve  having  entered  the  nostril  di- 
vides at  the  roof  of  the  cavity  into  two  branches, 
an  external  and  an  internal:  of  these  the  former 
descends  behind  the  nasal  process  of  the  frontal 
and  the  corresponding  nasal  bones,  contained 
in  the  groove  or  canal  observable  upon  their 
posterior  surface.  It  escapes  from  beneath 
them  at  their  inferior  margin,  emerging  between 
it  and  the  lateral  cartilage  of  the  nose,  and  then 
descends  along  the  corresponding  ala,  superfi- 
cial to  the  cartilage,  and  covered  by  the  mus- 
cles of  the  ala,  toward  the  tip  :  as  it  approaches 
the  tip,  it  divides  into  two  filaments,  one  of 
which  is  distributed  to  that  part,  and  the  other 
to  the  ala.  During  its  descent  along  the  side 
of  the  nose  it  also  gives  off  some  delicate  fila- 
ments, and  anastomoses  with  the  ramifications 
of  the  nasal  branches  of  the  infra-orbital  nerve 
and  with  the  portio  dura.  It  is  called  by 
Chaussier  the  naso-lobar :  it  is  also  generally 
known  as  the  nerve  of  Cotunnius.  The  second 
branch,  as  it  proceeds,  divides  presently  into 
two,  of  which  one  attaches  itself  to  the  septum, 
and  descends,  between  the  pituitary  membrane 
and  the  periosteum,  parallel  and  near  to  its  an- 
terior margin,  as  the  7iaso-palatine  of  Scarpa 
does  to  its  posterior  :  as  it  proceeds,  it  furnishes 
ramifications  to  the  membrane  of  the  septum. 
The  second  attaches  itself  to  the  outer  wall  of 
the  nostril,  and  descends,  in  like  manner  be- 
tween the  mucous  membrane  and  the  perios- 
teum, along  its  anterior  part,  in  front  of  the 
middle  turbinate  bone,  until  it  reaches  the  an- 
terior extremity  of  the  inferior  one  :  it  then 
breaks  up  into  branches,  of  which  some  are 
distributed  to  the  convex  surface  of  the  latter 
bone  in  front,  and  others  beneath  it  to  the  an- 
terior part  of  the  inferior  meatus.  The  distri- 
bution of  the  branch  is  very  happily  represented 
in  Arnold's  Icones. 

The  nasal  nerve  is  described  as  giving  also, 
in  some  instances,  but  not  uniformly,  a  branch 
to  the  membrane  of  the  superior  turbinate 
bone,  at  the  superior  part  of  the  nostril. 

3.  The  third  branch  of  the  first  division  of  the 
fifth  is  the  lachrymal:  it  has  been  so  called  by 
Winslow  from  its  distribution  to  the  lachrymal 
gland  :  it  is  the  smallest  of  the  three  branches  : 
its  course  is  external  to  that  of  the  others,  and 
hence  it  is  also  called  the  external  branch.  It 


»  J.  F.  Meckel. 


*  The  elder  Meckel. 


FIFTH  PAIR  OF  NERVES. 


283 


arises,  for  the  most  part,  from  the  ophthalmic 
at  the  same  time  with  its  other  branches ; 
J.  F-.  Meckel  asserts  that  it  arises  more  fre- 
quently from  a  trunk  common  to  it  and  the 
frontal ;  but  the  contrary  is  maintained  by 
the  elder  Meckel ;  he,  however,  states  that  it 
arises  frequently  by  two  roots,  one  from  the 
ophthalmic,  and  a  second  from  the  frontal,  and 
once  he  has  seen  it  derive  a  root  from  the  tem- 
poro-malar  branch  of  the  superior  maxillary 
nerve.*  When  it  arises  from  the  ophthalmic,  it 
is  at  its  origin,  inferior  to  the  frontal,  and  exter- 
nal to  the  nasal.  Its  course  is  forward  and 
outward  at  a  very  acute  angle  with  the  frontal ; 
it  enters  the  orbit  through  the  foramen  lacerum, 
and  from  its  origin  until  its  entrance  it  is  con- 
tained in  the  dura  mater  lining  the  inner  side 
of  the  middle  fossa  of  the  base  of  the  cranium, 
beneath  the  lesser  wing  of  the  sphenoid  bone  : 
in  entering  it  passes  above  the  origins  of  the 
external  rectus  muscle,  between  it  and  the  pe- 
riosteum, and  pursues  its  course  along  the 
outer  wall  of  the  orbit,  external  to  the  superior 
rectus  and  superior  to  the  external,  until  it 
reaches  the  lachrymal  gland  :  it  then  passes 
between  the  gland  and  the  eyeball,  and  then 
divides  into  branches.  It  is  accompanied 
through  its  course  by  the  lachrymal  artery. 
The  branches  into  which  it  divides  are,  for  the 
most  part,  three ;  they  enter  the  gland  on  its 
ocular  surface,  traverse  it  and  ae^un  escape 
from  it  on  its  external  aspect ;  in  their  course 
through  the  gland  they  divide  and  commu- 
nicate with  each  other,  and  thus  form  within 
it  a  plexus,  from  which  numerous  ramifications 
are  distributed  to  its  substance.  After  having 
supplied  the  gland  the  branches  of  the  lachry- 
mal emerge  from  it,  and  pursue  two  destina- 
tions :  one  of  them,  which  is  for  the  most  part 
the  first  branch  of  the  nerve,  and  is  frequently 
given  off  before  it  has  reached  the  gland,  de- 
scends backward  toward  thespheno-maxillary 
cleft,  and  joins  the  temporal  branch  of  the 
temporo-malar  branch  of  the  second  division  of 
the  fifth.  In  its  course  this  branch  passes  first 
between  the  external  rectus  muscle  and  the 
outer  wall  of  the  orbit,  then  becomes  attached 
to  the  wall,  and  is  either  simply  inclosed  in  the 
periosteum,  or  contained  in  a  groove  or  canal 
in  the  orbitar  process  of  the  malar,  or  some- 
times of  the  sphenoid  bone ;  in  this  canal  it  meets 
the  branch  of  the  temporo-malar,  and  from  the 
junction  of  the  two  results  a  filament,  the  des- 
tination of  which  will  be  described  under  that 
of  the  temporo-malar.  This  branch  of  the 
lachrymal  nerve  is  called  the  posterior  or  sphe- 
nomaxillary :  it  might  from  its  destination  be 
appropriately  termed  temporal:  it  frequently 
gives  off  in  its  descent  a  filament,  which  passes 
forward,  escapes  from  the  orbit  beneath  the  ex- 
ternal canthus,  and  is  distributed  as  the  other 
branches  of  the  lachrymal  are.  The  remaining 
branches  of  the  lachrymal  escape  from  the 
orbit  into  the  upper  eyelid,  beneath  the  exter- 

*  [According  to  Cruveilhier  the  lachrymal  nerve 
very  often  arises  by  two  filaments,  one  from  the 
ophthalmic,  the  other  from  the  fourth  nerve,  and 
Swan  describes  this  as  the  normal  condition. — 
Cruveilhier,  Anat.  Descr.  t.  iv.  p.  911. — Ed.] 


nal  part  of  the  superciliary  arch.  They  give 
off  numerous  filaments,  which  are  distributed 
to  the  structures  of  the  lid,  the  conjunctiva,  the 
orbicular  muscle,  and  the  integument :  the  ex- 
ternal of  them,  which  are  the  largest,  not  only 
supply  branches  to  the  upper,  but  descend  be- 
hind the  external  commissure  of  the  lids  into 
the  lower  one,  which  they  supply  at  its  outer 
part;  they  are  also  distributed  to  the  superfi- 
cial parts  on  the  malar  region.  They  anasto- 
mose with  the  frontal  nerve,  the  superficial 
temporal,  the  facial,  the  temporo-malar,  and 
the  infra-orbital  nerves. 

The  second  division  of  the  fifth. — This  has 
been  called  also  by  Winslow,  in  consequence 
of  its  distribution,  the  superior  maxillary  nerve. 
It  is  the  second  trunk  connected  with  the 
Gasserian  ganglion,  and  is  intermediate  to  the 
others,  both  in  size  and  situation  ;  larger  than 
the  first,  and  placed  beneath  and  external  to  it; 
smaller  than  the  third,  and  situate  internal, 
superior  and  anterior  to  it ;  it  is  attached  to  the 
middle  of  the  anterior  convex  margin  of  the 
ganglion  ;  at  first  it  is  flattened,  wide,  and  of  a 
cineritious  tint ;  but,  as  it  proceeds,  it  becomes 
contracted  in  width,  of  a  cylindrical  form,  and 
presents  a  white  colour.  At  leaving  the  gan- 
glion it  is  joined  by  a  filament  of  the  sympa- 
thetic. This  has  been  seen  by  Munniks*  and 
Laumonier,f  and  is  stated  by  Meckel  junior, 
on  the  authority  of  the  latter.  The  communi- 
cation between  the  sympathetic  and  the  second 
and  third  divisions  is  called  in  question  by 
Arnold.}  That  with  the  third  the  author  has 
not  yet  made  out,  but  that  with  the  second  he 
has  found  satisfactorily  established  by  a  fila- 
ment from  the  branch  of  the  sympathetic  which 
joins  the  sixth  nerve  :  this  filament  connects  the 
sixth  to  the  second  division  of  the  fifth,  and  is 
short,  but  grosser  than  those  which  join  the  first : 
in  consequence  of  the  irregularity  which  pre- 
vails in  the  arrangement  of  the  sympathetic 
system,  the  description  here  given  may  not 
apply  in  other  instances. 

The  course  of  the  second  division  of  the  fifth 
within  the  cranium  is  short ;  it  is  directed  for- 
ward, slightly  outward  and  downward,  toward 
the  superior  maxillary  or  the  foramen  rotundum 
of  the  sphenoid  bone ;  having  reached  that 
foramen  it  enters  the  canal,  of  which  it  is  the 
aperture,  and  escapes  through  it  from  the 
cranium.  While  within  the  latter  the  nerve 
is  contained  in  a  sheath  of  dura  mater,  and 
rests  in  a  shallow  channel  on  the  body  of 
the  sphenoid  bone,  at  its  junction  with  the 
great  ala.  From  the  cranium  it  enters  the 
spheno-maxillary  fossa,  and  crosses  that  fossa 
at  its  superior  extremity,  from  behind  forward, 
inclining  still  downward  and  outward,  though 
but  slightly  ;  its  course  across  the  fossa  is  also 
very  short,  extended  between  the  root  of  the 
pterygoid  process  behind  and  the  highest  part 
of  the  posterior  wall  of  the  maxillary  antrum 
before ;  having  traversed  the  superior  part  of 
the  fossa  it  enters  the  infra-orbital  canal,  through 

*  De  Origine  nervi  intercostalis. 
t  Roux,  Journ.  de  Med.  t.  xciii. 
X  Journ.  Comp.  t.  xxiv. 


284 


FIFTH  PAIR  OF  NERVES. 


which  it  is  transmitted,  in  company  with  the  in- 
fra-orbital artery,  to  the  face.  In  the  canal  it  is 
situate  in  the  floor  of  the  orbit  or  the  roof  of  the 
antrum,  separated  from  each  cavity,  more  or 
less  perfectly,  by  a  thin  lamina  of  bone ;  its 
course  within  the  canal  is  by  much  its  longest 
stage ;  as  the  nerve  approaches  the  anterior 
extremity  of  the  canal,  it  inclines  inward,  and 
thus  its  course  is  rendered  a  curve,  convex 
outward.  In  this  respect,  however,  it  pre- 
sents varieties,  dependant  upon  the  transverse 
dimensions  of  the  face,  which  being  great, 
the  course  of  the  nerve  is  more  curved  and 
vice  versa,  it  being  sometimes  nearly  straight. 
From  the  time  that  the  nerve  enters  the  canal, 
it  has  been  called  infra-orbital ;  but,  inasmuch 
as  that  part  of  it  is  manifestly  but  the  con- 
tinuation of  the  trunk,  and  names  are  already 
rather  too  numerous  than  otherwise,  it  would 
be  better  if  that  one  were  discarded.  From 
the  infra-orbital  canal  the  nerve  escapes  through 
its  anterior  aperture  into  the  face  ;  that  aperture 
corresponds,  for  the  most  part,  to  the  point  of 
junction  of  the  two  external  with  the  internal 
third  of  the  inferior  margin  of  the  orbit,  and  is 
from  a  quarter  to  half  an  inch  below  it ;  its 
situation,  however,  is  not  uniform ;  in  some 
skeletons  it  wdl  be  found  to  correspond  nearly 
to  the  middle  of  the  margin,  and  this  circum- 
stance is  worthy  of  attention,  in  consequence 
of  its  relation  to  the  operation  for  the  division 
of  the  nerve. 

At  its  escape  from  the  canal  the  nerve  is 
concealed  by  the  lower  margin  of  the  orbicu- 
laris palpebrarum  and  by  the  levator  labii  supe- 
rioris  muscle,  beneath  which  it  is  placed,  and 
it  is  above  the  upper  extremity  of  the  origin  of 
the  levator  anguli  oris  :  immediately  after  its 
escape  it  separates  into  a  number  of  branches, 
which  go  off  in  different  directions  to  their 
several  destinations,  but  principally  downward. 

The  branches  which  the  second  division 
gives  off  are  the  temporo-malar,  the  spheno- 
palatine, the  posterior  superior  dental,  the  an- 
terior superior  dental,  and  the  facial  branches. 
While  within  the  cranium  the  nerve  gives  off 
no  branch. 

1.  The  first  branch  given  off  by  the  second 
division,  the  temporo-malar,  has  been  called 
cutaneous  malar  by  the  elder  Meckel ;  it  has 
been  also  called  orbitar,  but  without  good 
reason  ;  the  name  temporo-malar  fully  expresses 
its  distribution.  This  branch  is  given  off  by 
the  nerve,  either  while  yet  within  the  canal, 
through  which  it  escapes  from  the  cranium,  or 
after  it  has  entered  the  spheno-maxillary  fossa  ; 
it  is  one  of  its  smallest  branches ;  it  passes  for- 
ward through  the  fossa,  toward  the  spheno- 
maxillary cleft,  enters  the  orbit  through  the 
cleft,  and  then  pursues  its  course  forward  and 
outward,  along  the  floor  of  that  region,  beneath 
the  inferior  rectus  muscle,  and  about  the  mid- 
dle of  it  divides  into  two  branches  ;  an  exter- 
nal, the  temporal,  and  an  anterior,  the  malar. 

Before  entering  the  orbit  it  sometimes  gives 
off  a  small  branch,  which  enters  that  cavity 
through  the  periosteum  of  the  posterior  part  of 
the  orbitar  process  of  the  sphenoid  bone,  and 
joins  the  lachrymal  branch  of  the  first  division, 


presenting  one  of  the  instances  of  a  second  root 
to  that  branch,  as  described  by  the  elder  Meckel. 

The  external  temporal  branch  passes  toward 
the  outer  wall  of  the  orbit,  ascends  between  it 
and  the  external  rectus  muscle ;  then  becomes 
attached  to  the  wall,  and  continues  its  course 
either  through  the  periosteum,  or  in  a  groove, 
or  at  times  through  a  canal  in  the  orbitar  pro- 
cess of  the  malar,  or  occasionally  of  the  sphe- 
noid bone ;  here  it  is  joined  by  the  posterior 
temporal  branch  of  the  lachrymal  nerve,  the 
third  branch  of  the  first  division  :  the  conjoined 
branch  is  then  transmitted  into  the  temporal 
fossa,  through  an  aperture  on  the  temporal  sur- 
face of  the  orbitar  process  of  the  malar  bone  ; 
there  it  is  joined  by  a  small  branch  of  the  an- 
terior deep  temporal  branch  of  the  inferior 
maxillary  or  third  division  of  the  fifth,  and 
plunging  among  the  fibres  of  the  temporal 
muscle,  it  is  distributed  to  them  in  common 
with  the  filaments  of  the  deep  temporal ;  a 
filament  or  filaments  of  it  gain  the  superficial 
surface  of  the  muscle,  perforate  its  aponeurosis, 
become  subcutaneous,  and  are  distributed  su- 
perficially upon  the  temple,  communicating 
with  filaments  of  the  portio  dura,  and  of  the 
superficial  temporal  branch  of  the  third  divi- 
sion. The  temporal  branch  of  the  temporo- 
malar  is  sometimes  double,  or  divides  into  two, 
one  communicating  with  the  branch  of  the 
lachrymal,  the  other  transmitted  to  the  temple. 

The  malar  branch  pursues  the  course  of  the 
original  nerve,  until  it  has  reached  nearly  to 
the  anterior  margin  of  the  orbit,  at  its  inferior 
external  angle  ;  then  it  enters,  either  single  or 
divided  into  two,  the  corresponding  canal  or 
canals,  by  which  the  malar  bone  is  perforated, 
and  through  them  is  transmitted  outward  and 
forward  to  the  malar  region  of  the  face.  Its 
ramifications  are  distributed  to  the  inferior  ex- 
ternal part  of  the  orbicularis  palpebrarum,  and 
to  the  integuments  of  the  malar  region  ;  they 
communicate  with  those  of  the  portio  dura,  of 
the  superficial  temporal  and  lachrymal  nerves, 
and  of  the  palpebral  branches  of  the  second 
division.  Before  reaching  the  malar  canals, 
the  malar  branch  frequently  gives  off  one  or 
more  filaments,  which  ascend  to  the  lachrymal 
gland,  unite  with  those  of  the  lachrymal  nerve, 
and  follow  a  similar  distribution. 

•2.  The  branches,  which  are  given  off  next  by 
the  second  division  of  the  fifth,  are  those  by 
which  the  nerve  is  connected  to  the  spheno- 
palatine ganglion;  they  are  hence  denominated 
the  spheno-palatine  ;  the  ramifications  derived 
from  thein,  or  from  the  ganglion  with  which 
they  are  connected,  are  distributed  to  the  nos- 
tril and  the  palate,  and  they  may  hence  with 
more  propriety  be  termed  the  naso-palatine, 
an  appellation  which  is  the  more  appropriate, 
since  it  is  already  applied  to  the  corresponding 
branch  of  the  second  division  of  the  fifth  in 
other  animals.  It  is  at  the  same  time  to  be 
borne  in  mind  that  a  difficulty  has  been  created 
in  this  matter  by  the  application  of  the  epithet 
in  question  to  certain  secondary  branches,  to  be 
mentioned  by  and-by;  but  the  latter  use  of  the 
term  ought  to  be  discarded.  They  are  irregular 
in  number,  there  being  sometimes  but  one,  at 


FIFTH  PAIR  OF  NERVES. 


285 


others  two  or  three :  they  are  short  and  of  con- 
siderable size,  and  arise  from  the  inferior  side 
of  the  nerve,  immediately  after  it  has  entered 
the  spheno-maxillary  fossa  ;  they  descend  from 
it,  almost  perpendicularly,  into  the  fossa,  pos- 
terior to  the  internal  maxillary  artery,  and  im- 
mersed in  fat,  and  after  a  very  short  course 
they  are  connected  to  the  ganglion,  from  which 
they  may  seem  to  ascend  to  the  nerve.  They 
are  thus  described  by  Cloquet,  but  this  view  is 
not  sanctioned  either  by  comparative  anatomy, 
or  by  the  result  of  experiments,  both  which 
prove  that  they  are  to  be  considered  branches 
of  the  nerve,  with  which  the  ganglion  is  con- 
nected. 

The  ganglion  has  been  first  described  by 
the  elder  Meckel,*  and  hence  has  also  received 
the  title  of  Meckel's  ganglion  ;  it  is  very  small, 
of  a  grey  colour,  and  firm  consistence ;  its 
shape  is  triangular  or  cordiform,  one  surface 
directed  outward,  the  other  inward ;  it  is  situate 
immediately  external  to  the  spheno-palatine 
foramen,  its  internal  surface,  which  is  flat,  cor- 
responding to  the  foramen,  its  external,  which 
is  convex,  to  the  zygomatic  fossa.    It  is  subject 
to  variety  ;  in  some  instances  it  is  wanting, 
and  then  the  spheno-palatine  nerve  gives  off 
those  branches  which  otherwise  arise  from  the 
ganglion :    in  other  rare  cases,  according  to 
Meckel,  the  two  principal  branches,  which 
arise  from  the   ganglion  when   present,  or 
from  the  spheno-palatine  when  single,  viz.  the 
Vidian  and  the  palatine, proceed  separately  from 
the  trunk  of  the  second  division  of  the  fifth  ;  in 
others  again  the  author  has  observed  a  cineri- 
tious  soft  enlargement  upon  the  Vidian  nerve 
at  its  junction  with  the  spheno-palatine,  but 
not  involving  that  nerve  or  the  branches  pro- 
ceeding from  it ;  and  this,  it  is  worth  remark- 
ing, is  precisely  the  disposition  of  the  ganglion 
in  the  dog  and  some  other  animals.  Different 
views  have  been  taken  of  the  nature  and  rela- 
tions of  this  ganglion :  the  Meckels,  by  the 
elder  of  whom  it  was  discovered,  Bichat,  Boyer, 
and  others,  have  regarded  it  as  belonging  pro- 
perly to  the  fifth  nerve,  and  formed  by  the 
branches  which  have  been  mentioned  :  Cloquet, 
on  the  other  hand,  considers  and  describes  it 
as  a  part  of  the  ganglionic  or  sympathetic 
system,  and  all  the  nerves  connected  with  it, 
as  well  the  original  spheno-palatine  branches 
as  the  others,  to  be  branches  from  it :  Cruveil- 
hier  again,  while  he  admits  the  existence  of 
ganglionic  structure,  yet  leaves  it  uncertain 
whether  he  regards  it  as  a  sympathetic  or  a 
cerebro-spinal  ganglion,  but  he  differs  from 
Cloquet  in  maintaining  that  "  the  nerves," 
which  seem  to  arise  from  it,  "  are  not  detached 
from  the  ganglion  itself,  and  come  directly 
from  the  superior  maxillary."    The  opinions  of 
Cloquet  and  Cruveilhier  appear  to  the  author 
to  be  both,  to  a  certain  degree,  well-founded. 
The  ganglion  would  seem  not  to  be  properly  a 
part  of  the  fifth  nerve,  because,  1 .  it  is  not,  as 
he  believes,  present  in  animals  below  the  mam- 
malia ;  2.  it  is  not  always  present  even  in  them, 
and  in  neither  case  is  the  general  distribution 


of  the  part  of  the  fifth  nerve,  with  which  it  is 
connected,  influenced  by  its  absence ;  3.  it  is 
manifestly  different  in  its  characters  from  the 
fifth  nerve  and  from  the  branches  of  the  nerve 
to  which  it  is  attached,  nor  does  it  resemble 
the  cerebro-spinal  ganglia,  the  peculiar  appear- 
ance of  these  bodies,  viz.  white  filaments  enter- 
ing and  emerging,  their  continuity  being  appa- 
rently interrupted  by  an  interposed  mass  of 
cineritious  matter,  not  being  observable ;  while, 
on  the  other  hand,  it  resembles  the  ganglia  of 
the  sympathetic,  and  is  actually  connected  with 
that  nerve  by  a  branch  having  precisely  the 
same  qualities  with  those  which  proceed  from 
it,  viz.  by  the  inferior  branch  of  the  Vidian 
nerve :  for  those  reasons  the  author  would 
adopt  the  opinion  of  Cloquet,  that  the  ganglion 
is  properly  a  part  of  the  ganglionic  system,  and 
that  it  is  only  accessory  to  the  fifth  nerve.  On 
the  other  hand,  it  appears  to  him  that  Cloquet 
is  mistaken  in  considering  the  ganglion  as  the 
source  of  all  the  nervous  filaments  connected 
with  it,  and  more  particularly  of  the  spheno- 
palatine branches  of  the  second  division  of  the 
fifth,  to  which  in  man  the  ganglion  is  attached, 
for,  as  has  been  already  stated,  the  general  dis- 
tribution and  existence  of  these  branches  are 
not  at  all  influenced  by  the  absence  of  the  gan- 
glion, and  when  present  it  allows  in  general,  as 
Cruveilhier  has  observed,  the  nerves  to  be  fol- 
lowed up  and  down  from  the  swelling,  and 
lastly,  any  obscurity  existing  with  regard  to 
this  point  in  the  human  subject  will  be  at  once 
removed  by  reference  to  the  disposition  of  the 
ganglion  in  other  animals,  in  none  of  which 
that  the  author  has  examined  does  it  involve 
the  nerve,  but  is  merely  connected  to  it  either 
by  filaments  or  by  one  extremity,  the  continuity 
of  the  nerve  being  altogether  uninterrupted, 
and  a  marked  contrast  being  to  be  observed 
between  the  characters  of  the  two  parts  :  thus 
in  the  dog,  the  ganglion  is  an  oblong  dark- 
grey  swelling,  with  the  posterior  extremity  of 
which  the  Vidian  nerve  is  united,  while  its  an- 
terior is  attached  to  the  naso-palatine  nerve. 
The  author,  therefore,  concurs  in  the  opinion  of 
Cruveilhier,  so  far  as  to  regard  the  nerves  con- 
nected with  the  ganglion,  for  the  greater  part, 
as  branches  of  the  fifth  nerve  and  not  of  the 
ganglion;  but  he  would  exclude  from  this  view 
the  Vidian  nerve,  or  at  least  its  carotidean 
branch,  which  appears  to  him  to  belong  to  the 
sympathetic  system.  (See  posterior  branch  of 
ganglion.) 

The  disposition  of  this  ganglion  throughout 
the  animal  series  is  an  object  of  interest.  The 
author  cannot  assert  its  existence  in  the  mam- 
malia universally,  but  from  indirect  considera- 
tions it  appears  to  him  likely  that  it  does  exist; 
generally  at  least,  in  animals  of  that  class.  It 
is  asserted  in  the  work*  of  Desmoulins  and 
Majendie  on  the  Anatomy  of  the  Nervous  Sys- 
tem in  vertebrate  Animals,  that  "  there  does 
not  exist  any  trace  of  it  in  cats,  dogs,  the  rumi- 
nantia,  the  rodentia,  the  horse,  &c. ;"  and  it  is 
reasonable  to  infer  that  they  had  found  it  in 
others.    Now  their  statement  with  regard  to 


*  Mem.  de  l'Acad.  de  Berlin,  1794, 


*  Tom,  ii.  p.  396, 


286 


FIFTH  PAIR  OF  NERVES. 


its  absence  is,  in  the  majority  of  the  instances 
which  they  have  selected,  positively  incorrect, 
for  the  author  has  ascertained  its  existence 
most  satisfactorily  in  the  dog,  the  horse,  the 
cat,  the  cow,  and  the  rabbit.  Nor  is  any  ex- 
ception to  its  existence  mentioned  by  Cuvier, 
and  hence  he  thinks  it  likely  that  it  does  exist 
generally,  if  not  universally,  throughout  the 
class.  It  is  not  however  similarly  disposed  in 
all ;  in  some  it  is  connected  with  the  primitive 
naso-palatine  nerve ;  in  others  with  its  nasal ; 
and  in  others  again  with  its  palatine  division  : 
in  some  it  gives  off  few  filaments ;  in  others, 
the  horse,  e.  g.  they  are  numerous  beyond  de- 
scription. The  ganglion  does  not  appear  to 
exist  in  the  inferior  classes. 

From  the  spheno-palatine  ganglion  or  nerve, 
according  to  the  view  of  their  source  adopted, 
there  is  given  off  a  considerable  number  of 
branches,  which  run  in  different  directions  and 
have  different  destinations:  they  have  been 
distinguished  into  four  sets,  viz.  superior,  infe- 
rior, internal,  and  posterior.  The  superior 
branches  are  very  delicate  and,  in  some  in- 
stances at  least,  numerous.  Among  them  are 
described  and  represented  by  Arnold  two  long 
slender  filaments,  which  join  the  optic  :  ano- 
ther is  also  mentioned  by  him  to  be  sometimes 
found  connected  with  the  ophthalmic  ganglion. 
The  discovery  of  this  connection  between  the 
two  ganglia  is  due  to  Tiedemann,  who  found, 
upon  the  left  side  of  a  man,  an  anastomosis 
between  them,  established  by  a  filament,  of 
tolerable  size,  which,  arising  from  the  inner  face 
of  the  spheno-palatine,  entered  the  orbit  and 
passing  above  the  inferior  branch  of  the  motor- 
oculi  nerve,  where  it  gives  off  the  short  root, 
went  in  company  with  the  last  to  gain  the  in- 
ferior and  posterior  part  of  the  ophthalmic  gan- 
glion ;*  and  beside  those  there  may  be  found, 
in  favourable  subjects,  others,  which  seem 
destined  to  the  posterior  ethmoidal  cells.  The 
inferior  branch  is  the  largest  given  off  by  the 
ganglion;  it  is  distributed  principally  to  the 
palate,  and  hence  is  called  "  the  palatine ;" 
but  it  supplies  the  nostril  also  in  part,  and 
hence  it  has  been  suggested  by  J.  F.  Meckel, 
that  it  might  be  appropriately  called  the 
"  naso-palatine :"  this  appellation  has,  however, 
been  applied  by  Scarpa  to  one  of  the  internal 
branches,  and  it  has  been  already  explained 
that  it  belongs  more  properly  to  the  original 
branch  before  its  junction  with  the  ganglion. 
The  palatine  nerve  descends  from  the  ganglion 
into  the  spheno-maxillary  fossa,  posterior  to 
the  internal  maxillary  artery  and  toward  the 
pterygo-palatine  canals,  and  after  a  short  course 
divides  into  three  branches ;  an  anterior,  larger 
one,  denominated  "  the  great  palatine,"  and 
two  posterior  smaller  branches,  "  the  lesser 
palatine  nerves." 

These  branches  continue  to  descend  in  com- 
pany until  they  reach  the  superior  apertures  of 
the  canals ;  they  then  enter  the  canals  and  are 
transmitted  downward  through  them  to  the 
palate  and  fauces.  The  great  palatine  descends 
through  the  anterior  pterygo-palatine  canal, 

*  Journal  Compl.  vol.  xxiv.  Arnold. 


in  company  with  a  branch  of  the  palatine 
artery,  at  the  same  time  inclining  forward  : 
during  its  descent  it  gives  off,  in  some  in- 
stances before,  in  others  after  it  has  entered 
the  canal,  either  one  or  two  filaments,  which 
descend  inward,  pass  through  the  nasal  process 
of  the  palate  bone,  and  enter  the  nostril  at  the 
back  part  of  the  middle  meatus,  between  the 
posterior  extremities  of  the  middle  and  in- 
ferior turbinate  bones :  one  of  them  is  dis- 
tributed to  the  membrane  of  the  middle  bone 
and  of  the  middle  meatus ;  the  other  to  that 
of  the  convex  surface  of  the  inferior  bone : 
when  a  single  branch  arises  from  the  palatine 
it  divides  into  two,  which  follow  a  similar 
distribution ;  these  branches  are  denominated 
by  the  elder  Meckel  inferior  nasal  nerves  in  con- 
tradistinction to  the  superior  nasal,  to  be  de- 
scribed, given  off  by  the  ganglion  and  by  the 
Vidian  nerve.  Another  filament  is  described 
by  Cloquet  arising  from  the  palatine  shortly 
before  it  escapes  from  the  canal,  entering  the 
nostril  through  the  perpendicular  plate  of  the 
palate  bone,  running  along  the  margin  of  the 
inferior  turbinate  bone,  and  lost  upon  the 
ascending  process  of  the  superior  maxillary 
bone,  often  also  contained  in  an  osseous  canal. 

The  great  palatine  nerve,  then,  for  the  most 
part  divides  into  three  branches,  of  which  one, 
the  smallest,  descends  through  an  accessory 
canal,  in  the  pterygoid  process  of  the  palate- 
bone,  leading  from  the  anterior,  and  escapes 
from  it  inferiorly  into  the  soft  palate  in  which 
it  is  consumed. 

The  other  two  escape  from  the  pterygo- 
palatine canal,  through  the  posterior  palatine 
foramen,  into  the  palate  :  at  emerging  from 
the  foramen  they  are  situate  very  far  back, 
in  the  posterior  angle  of  the  hard  palate  on 
either  side,  and  behind  the  last  molar  tooth 
of  the  upper  jaw;  they  are  immediately  super- 
ficial to  the  periosteum,  and  above  the  other 
structures  of  the  palate  ;  they  are  lodged, 
along  with  the  branches  of  the  accompanying 
artery,  in  channels  upon  the  inferior  surface 
of  the  palatine  processes  of  the  palate  and  the 
superior  maxillary  bones;  they  pass  forward, 
one  along  the  alveolar  arch,  the  other  toward 
the  middle  line  of  the  palate,  and  subdivide, 
each,  into  several  branches,  which  are  dis- 
tributed to  the  structures  of  the  hard  palate, 
the  mucous  glands  and  membrane,  and  to  the 
gums,  and  communicate  in  front  with  branches 
of  the  naso-palatine  ganglion. 

In  some  instances  the  palatine  nerve  does 
not  divide  into  those  ultimate  branches  until 
after  it  has  escaped  from  the  palatine  canal ; 
but  their  disposition  in  such  cases  is  in  other 
respects  the  same. 

The  lesser  palatine  nerves  are  posterior  to 
the  greater ;  they  are  transmitted  also  through 
the  pterygo-palatine  canals,  the  first  through  the 
posterior,  the  second  through  the  external. 

The  first,  the  larger  of  the  two,  and  called 
middle  palatine  nerve,  escapes  from  the  canal 
inferiorly  in  front  of  the  hamular  process  of  the 
sphenoid  bone,  and  divides  into  filaments, 
which  are  distributed  to  the  soft  paiate  and  its 
muscles. 


FIFTH  PAIR  OF  NERVES. 


The  second,  the  posterior,  little  palatine 
nerve,  descends  at  first  between  the  external 
pterygoid  muscle  and  the  posterior  wall  of  the 
antrum,  then  enters  the  canal,  and  escapes 
inferiorly  external  to  the  former ;  it  divides 
into  two  filaments,  one  of  which  is  distributed 
to  the  soft  palate,  the  other  to  the  tonsils  and 
arches  of  the  palate. 

Those  branches  are  accompanied  by  minute 
branches  of  the  palatine  artery. 

The  internal  branches  vary  in  number  from 
three  to  five;  they  arise  from  the  inner  surface 
of  the  ganglion,  run  directly  inward,  posterior 
to  the  nasal  branch  of  the  internal  maxillary 
artery,  toward  the  spheno-palatine  foramen, 
which  they  immediately  reach  ;  pass  through 
the  foramen,  perforating  the  structure  by  which 
it  is  closed,  and  enter  the  nostril,  and  thus 
attach  the  ganglion  closely  to  the  foramen  : 
at  their  entrance  into  the  nostril  they  are  situate 
before  and  beneath  the  anterior  wall  of  the 
sphenoidal  sinus,  at  the  back  part  of  the  su- 
perior meatus,  and  immediately  above  the 
posterior  extremity  of  the  middle  turbinate 
bone. 

They  are  distinguishable,  according  to  the 
majority  of  descriptions,  into  two  sets;  one 
destined  to  the  outer  wall  of  the  nostril  and 
denominated  by  Meckel  anterior  superior 
nasal,  in  contradistinction  to  branches  of 
the  Vidian  nerve,  which  he  has  designated 
"  posterior  superior  nasal,"  and  another  con- 
nected with  the  septum.  A  third  destination 
has  been  assigned  to  them  by  Arnold,  accord- 
ing to  whom  a  branch  derived  either  from  one 
of  the  nerves  of  the  septum,  or  originally  from 
the  ganglion  itself,  is  distributed  to  the  supe- 
rior part  of  the  pharynx,  corresponding  to  the 
pharyngeal  branch  of  Bock. 

The  anterior  superior  nasal  branches  are 
either  one  or  two  in  number ;  when  but  one, 
it  divides  into  branches  corresponding  to  the 
two;  it  is  so  expressed  in  Arnold's  fifth  plate  ; 
one  of  the  two  divides  into  filaments,  which 
are  distributed  to  the  posterior  ethmoidal  cells, 
to  the  posterior  part  of  the  superior  turbinate 
bone,  and  to  the  superior  meatus,  to  the  mem- 
brane of  those  parts.  The  second  distributes 
its  filaments  to  the  convex  surface  of  the  mid- 
dle turbinate  bone;  according  to  Cloquet  they 
in  part  perforate  the  bone,  and  thus  gain  its 
concave  surface :  they  all  run  between  the 
periosteum  and  the  mucous  membrane,  and 
are  distributed  finally  to  the  latter. 

The  branches  connected  with  the  septum  are 
two,  a  short  and  a  long  one ;  they  both  pass 
across  the  anterior  wall  of  the  sphenoidal 
sinus  from  without  inward,  and  thus  reach 
the  posterior  part  of  the  septum  nasi,  become 
attached  to  it,  and  changing  their  direction 
descend  forward  along  it,  between  the  perios- 
teum and  mucous  membrane. 

The  short,  lesser,  branch  is  situate  very  near 
to  the  posterior  margin  of  the  septum,  to 
which  it  is  parallel  in  its  course,  and  distri- 
butes its  filaments  to  the  membrane  of  the 
posterior  part  of  it :  one  of  them  is  repre- 
sented by  Arnold  as  constituting  the  pharyn- 
geal branch. 


The  long  branch  descends  to  the  superior 
aperture  of  the  anterior  palatine  canal,  enters 
the  canal,  and  in  it  the  nerves  of  the  two  sides 
are  united  to  a  small  ganglion  denominated 
the  naso -palatine  ;  from  it  filaments  descend 
to  the  anterior  part  of  the  palate,  in  which 
they  are  distributed  and  communicate  with 
filaments  of  the  palatine  nerves.  Each  nerve, 
during  its  course  along  the  septum,  is  situate 
nearer  to  its  position  inferior  than  to  its  supe- 
rior anterior  margins :  it  is  said  not  to  give 
any  filaments  during  its  descent,  but  this  is 
incorrect,  as  is  well  represented  by  Arnold  ; 
those,  which  it  gives  off,  are  distributed  to  the 
membrane  of  the  septum  about  its  middle; 
at  times  also  it  divides  into  two  filaments, 
which  are  afterwards  reunited.  Each  nerve  is 
received  inferiorly  in  a  separate  canal,  which 
inclining  inward  is  soon  united  to  the  other 
in  the  palatine,  and  in  it  the  nerve  or  the 
naso-palatine  ganglion  receives  a  filament  of 
communication  from  the  anterior  superior  den- 
tal branch  of  the  second  division  of  the  fifth, 
as  described  by  Cloquet. 

This  branch  has  been  particularly  described, 
first  by  Scarpa,*  and  by  him  denominated 
the  naso-palatine ;  it  has  been  also  described 
by  J.  Hunter,-}-  between  whom  and  Scarpa 
appears  to  lie  the  merit  of  having  first  ob- 
served it ;  it  is  also  known  as  "  the  nerve  of 
the  septum,"  but  the  latter  appellation  is  ma- 
nifestly incorrect;  nor  is  the  former  free  from 
objection,  inasmuch  as  the  same  title  has  been 
applied,  and  with  reason,  in  the  inferior  Mam- 
malia, to  the  original  branch  given  off  by  the 
second  division  of  the  fifth  for  the  supply  of 
the  nostril  and  palate,  with  which  the  spheno- 
palatine ganglion  is  connected,  and  which  in 
man  has  received  the  name  of  spheno-palatine 
branch.  The  branch  of  the  ganglion  in  ques- 
tion is  called  by  some  the  nerve  of  Cotunnius, 
but  incorrectly  ;  having  been  first  described  by 
Scarpa,  it  cannot  with  justice  be  attributed  to 
the  former. 

The  posterior  branch  of  the  ganglion  is  de- 
scribed and  represented  by  the  majority  of 
authorities  as  arising  single  and  in  its  course 
dividing  into  two  filaments;  but  Bock,  J.  F. 
Meckel,  and  Hirzel  state  that  the  two  fila- 
ments at  times  are  throughout  distinct  and 
connected  separately  to  the  ganglion;  and 
Arnold  represents,  in  like  manner,  two  fila- 
ments arising  from  the  ganglion,  corresponding 
to  the  two  into  which  the  single  nerve  divides. 
The  posterior  branch  arises  from  the  back  of 
the  ganglion,  passes  directly  backward  from  it, 
and  is  received  immediately  into  the  pterygoid 
or  Vidian  canal,  along  with  the  corresponding 
branch  of  the  internal  maxillary  artery :  it 
is  transmitted  through  the  canal  backward 
and  slightly  outward,  beneath  the  course  of 
the  second  division  of  the  fifth  itself,  and 
external  to,  or  in  many  instances  beneath  the 
sphenoidal  sinus ;  having  traversed  the  canal, 

*  Annotationes  Academics,  in  which  is  also  con- 
tained a  good  representation  of  the  nerve  as  a 
single  branch. 

t  Animal  (Economy. 


288 


FIFTH  PAIR  OF  NERVES. 


it  escapes  from  its  posterior  aperture  into  the 
foramen  lacerum  anterius  basis  cranii :  in  this 
it  is  contained  in  the  fibrous  structure  by 
which  the  foramen  is  closed,  and  is  situate 
at  the  outer  side  of  and  beneath  the  internal 
carotid  artery,  as  that  vessel  ascends,  from 
the  aperture  of  its  canal  in  the  petrous  bone, 
into  the  cavernous  sinus.  Here  also,  or  even 
before  it  has  escaped  from  the  Vidian  canal, 
it  receives,  when  single,  a  filament  of  com- 
munication from  the  superior  cervical  ganglion 
of  the  sympathetic :  this  filament  had  been 
long  regarded  as  arising  from  the  posterior 
branch  itself,  and — though  at  present  gene- 
rally* considered  a  branch  from  the  sympa- 
thetic— it  has  been  for  the  most  part  described, 
in  systematic  works,  as  such  under  the  name 
of  the  inferior,  deep,  sympathic,  or  carotidean 
branch  of  the  Vidian  nerve.  In  its  direction 
it  certainly  resembles  a  branch  of  that  nerve  ; 
but  in  that  particular  it  is  equally  entitled  to 
be  regarded  one  from  the  sympathetic  to  the 
spheno-palatine  ganglion,  it  being  either  from 
before  backward  and  from  above  downward, 
or  from  behind  forward  and  from  below  up- 
ward. Further,  in  sensible  qualities  it  strictly 
resembles  other  branches  of  the  latter  nerve ; 
it  is,  as  has  been  stated,  at  times  separate  from 
the  proper  Vidian,  and  connected  directly  with 
the  spheno-palatine  ganglion  ;  and  it  is,  in  fact, 
but  one  of  the  branches  which  ascend  into  the 
cranium  from  the  superior  cervical  ganglion 
along  the  internal  carotid  artery,  so  that  it 
would  be  equally  correct  to  describe  that  fila- 
ment which  is  connected  with  the  sixth  nerve 
as  a  branch  of  that  nerve,  as  to  style  the  fila- 
ment in  question  a  branch  of  the  Vidian  nerve. 

The  view  of  the  nature  of  this  filament  here 
advanced  is,  however,  not  universally  admitted. 
Cruveilhier  objects  to  it  because  the  cranial 
branch  of  the  Vidian  nerve  appears  to  him  to 
resemble  in  all  respects  the  carotidean :  this, 
however,  cannot  be  considered  a  valid  objec- 
tion, it  can  only  prove  that  one  branch  may  be 
as  much  allied  to  the  ganglionic  system  as  the 
other,  but  the  validity  of  the  assertion  may  be 
questioned ;  however  it  may  be  in  man,  the 
characters  of  the  two  branches  in  the  larger 
quadrupeds,  the  horse  e.  g.  are  sufficiently 
distinct,  the  cranial  branch  being  of  a  pure 
white  colour,  and  the  carotidean  having  a  gan- 
glionic enlargement  upon  it  at  its  junction  with 
the  cranial. 

While  traversing  the  pterygoid  canal,  soon 
after  it  has  entered  that  canal,  and  in  some  cases 
even  before,  the  posterior  branch  of  the  gan- 
glion gives  ofF  from  its  inner  side  two  or  three 
filaments,  denominated  by  the  elder  Meckel 
posterior  superior  nasal :  these  enter  the  poste- 
rior superior  part  of  the  nostril,  in  one  case  by 
passing  through  the  spheno-palatine  foramen, 
in  the  other  by  perforating  the  inner  wall  of 
the  pterygoid  canal,  and  are  distributed  to  the 
posterior  part  of  the  lateral  wall  of  the  nostril, 
to  the  root  of  the  septum,  to  the  sphenoidal 
sinus  and  to  the  lateral  wall  of  the  pharynx 
in  the  vicinity  of  the  orifice  of  the  Eustachian 


Bock,  Cloquet,  Hirzel,  J.  F.  Meckel. 


tube.  These  branches  frequently  arise  from 
the  ganglion  itself  by  a  single  filament,  de- 
nominated by  Bock  the  pharyngeal  nerve,  and 
represented  by  Arnold  among  die  internal 
branches  of  the  ganglion  :  it  divides  into  fila- 
ments distributed  to  the  several  parts  men- 
tioned. 

After  the  junction  of  the  sympathetic  fila- 
ment, the  posterior  branch  is  continued  through 
the  fibrous  structure  already  mentioned,  ex- 
ternal to  the  internal  carotid  artery,  and 
thus  enters  the  cranium.  It  then  passes  out- 
ward, backward,  and  upward,  upon  the  ante- 
rior surface  of  the  petrous  bone,  beneath 
the  third  division  of  the  fifth,  very  near 
its  attachment  to  the  Gasserian  ganglion, 
and  enclosed  in  the  dura  mater :  it  is  at  the 
same  time  lodged  in  a  channel  upon  the  sur- 
face of  the  bone.  It  is  stated  by  Cloquet  that 
it  here  sends  into  the  cavity  of  the  tympanum 
by  two  canals,  the  orifices  of  which  are  to  be 
seen  in  the  channel  one  above  the  other,  two 
filaments  of  extreme  delicacy,  which  go  to 
anastomose  together  upon  the  promontory,  and 
to  communicate  with  a  filament  of  the  supe- 
rior cervical  ganglion,  and  with  the  glosso- 
pharyngeal nerve.  According  to  Hirzel,*  this 
connection  between  the  superficial  branch  of 
the  Vidian  and  the  tympanic  branch  of  the 
glosso-pharyngeal  nerve  on  the  nerve  of  Jacob- 
son,  takes  place  in  the  vicinity  of  the  junction 
of  the  former  with  the  facial  nerve.  Accord- 
ing to  Arnold,f  the  superficial  branch  of  the 
Vidian  nerve  is,  as  proved  by  the  researches  of 
others  and  his  own,  not  simple,  but  composed 
of  two  or  of  several  filaments,  and  is  accom- 
panied by  one  or  more  very  delicate  filaments 
from  the  carotid  plexus.  In  one  instance  he 
found  the  petrous  nerve  composed  of  four 
filaments  on  the  right,  and  three  on  the  left. 
The  existence  of  several  distinct  filaments  in 
the  Vidian  nerve  may  be  easily  observed  in  the 
larger  animals.  It  pursues  the  course  men- 
tioned, until  it  has  reached  the  hiatus  Fallopii, 
through  which  it  is  transmitted  to  the  aqueduct 
of  Fallopius,  where  it  meets  and  becomes  in- 
timately connected  with  the  facial  portio  dura 
nerve.  At  their  junction  the  facial  nerve  pre- 
sents a  gangliform  swelling,  from  which  two 
very  delicate  filaments  proceed  to  the  auditory 
nerve.  J 

From  the  time  that  the  posterior  branch  of 
the  ganglion  enters  the  cranium  until  it  has 
joined  the  facial  nerve,  it  is  called  the  cranial 
or  superficial  petrous  branch  of  the  Vidian 
nerve ;  by  Arnold  petrosus  superficialis  major 
in  contradistinction  to  another  nervous  filament, 
which  connects  his  '  otic'  ganglion  to  the  tym- 
panic branch  of  the  glosso-pharyngeal  nerve  ; 
but  the  application  of  either  of  these  epithets 
would  be  rendered  unnecessary  by  ceasing  to 
consider  the  filament  by  which  the  posterior 
branch  of  the  ganglion  is  connected  to  the 
sympathetic,  a  branch  of  the  former. 

The  posterior  branch  is  also  known  by  other 

*  Journ.  Corapl.  t.  xxii. 
+  Journ.  Compl.  t.  xxiv. 

%  Arnold.  See  lingual  branch  of  third  division 
and  chorda  tympani. 


j1>  ()?■ 


FIFTH  PAIR  OF  NERVES. 


289 


names,  viz.  the  recurrent,  the  pterygoid,  the 
Vidian,  the  anastomotic,  or  sympathies. 

3.  The  next  branch  or  branches  of  the  su- 
perior maxillary  nerve  are  the  posterior  supe- 
rior dental.  These  arise  from  the  nerve  in 
front  of  the  internal  maxillary  artery,  between 
it  and  the  back  of  the  antrum,  and  are  sepa- 
rated from  the  artery  by  the  spheno-palatine  ; 
they  are  very  irregular  as  to  their  number  and 
precise  place  of  origin ;  at  times  there  is  but 
one  branch,  at  others  there  are  two  or  three  : 
they  are  distributed  to  the  buccinator  muscle 
and  the  mucous  membrane  of  the  posterior 
lateral  part  of  the  mouth,  to  the  roots  of  the 
posterior  teeth,  the  membrane  of  the  maxil- 
lary antrum,  and  the  gum  of  the  upper  jaw. 
When  but  one  branch  is  present,  its  sub- 
divisions supply  the  place  of  the  others.  It 
descends  into  the  fossa,  behind  the  superior 
maxillary  bone,  and  before  the  internal  maxil- 
lary artery,  and  after  a  certain  way  divides 
into  two  branches  or  sets  of  branches,  posterior 
and  anterior. 

The  posterior  consists  of  several  long  slen- 
der filaments,  which  continue  to  descend  im- 
mersed in  the  fat  of  the  zygomatic  fossa,  until 
they  reach  the  surface  of  the  buccinator  muscle; 
they  then  in  part  are  distributed  to  it,  but  in 
greater  number  pass  between  the  fibres  of  the 
muscle  and  are  lost  in  the  mucous  membrane 
of  the  mouth. 

The  anterior  branch  descends  for  some  time, 
until  it  reaches  the  back  of  the  maxilla;  it 
then  enters  a  canal  in  the  bone,  within  which 
it  is  transmitted  forward  through  the  wall  of 
the  antrum ;  after  a  short  way  it  escapes  from 
the  canal  and  continues  its  course  forward 
within  the  wall,  between  it  and  the  lining 
membrane,  describing  a  curve  convex  down- 
ward ;  having  reached  the  front  of  the  antrum 
it  ascends  and  terminates  by  joining  either  the 
anterior  superior  dental  or  a  branch  of  that 
nerve. 

During  its  course  around  the  antrum  the 
anterior  branch  of  the  nerve  gives  off  down- 
ward numerous  delicate  filaments,  which  de- 
scend toward  the  teeth,  traverse  the  structure 
of  the  alveolar  arch,  and  in  part  are  distributed 
to  the  roots  of  the  posterior  superior  teeth  in 
a  manner  analogous  to  that  of  the  inferior 
dental  nerves  :  in  part  they  escape  inferiorly 
from  the  alveolar  arch  between  the  sockets  of 
the  teeth,  and  are  consumed  in  the  gums. 
The  nerve  is  also  stated  to  give  filaments  to  the 
membrane  of  the  maxillary  antrum. 

4.  Shortly  before  its  escape  from  the  infra- 
orbital canal,  but  at  a  distance  somewhat 
variable  from  it,  the  second  division  of  the 
fifth  gives  oft"  its  next  regular  branch,  the 
anterior  superior  dental :  this  descends,  from 
tbe  infraorbital  canal,  through  one  of  its  own 
name  in  the  anterior  wall  of  the  antrum  to- 
ward the  canine  tooth  ;  it  next  runs  inward 
above  the  root  of  that  tooth,  and  then  again 
descends  through  the  perpendicular  process 
of  the  maxillary  bone,  until  it  reaches  the  floor 
of  the  nostril,  and  is  continued  inward  through 
the  horizontal  process  of  the  bone  above  the 
roots  of  the  incisor  teeth. 

VOL.  II. 


While  descending  through  the  wall  of  the 
antrum  the  anterior  superior  dental  nerve 
either  is  joined  by  the  termination  of  the  anterior 
branch  of  the  posterior  dental,  or  it  divides  into 
two,  one  of  which  inclines  outward  and  joins 
that  branch,  the  other  pursues  the  course  of 
the  nerve.  It  supplies  the  anterior  teeth  of 
the  upper  jaw  in  the  same  manner  as  the  pos- 
terior nerve  does  the  posterior  teeth  ;  it  also 
gives  at  its  termination  filaments  to  the  mem- 
brane of  the  nostril,  and  one  to  the  naso- 
palatine ganglion  or  nerve. 

Besides  the  regular  dental  nerves,  others  at 
times  arise  from  the  second  division  of  the 
fifth  within  the  infraorbital  canal,  and  take  the 
place  of  branches  of  the  regular  nerves. 

5.  The  facial  brandies  of  the  second  division 
of  the  fifth  are  from  five  to  seven  in  number ; 
they  differ  from  each  other  in  size,  and  branch 
off  in  different  directions;  they  are  distin- 
guished, according  to  the  direction  in  which 
they  run  and  their  destination,  into  three  sets; 
a  superior  or  palpebral,  an  inferior  or  labial, 
and  an  internal  or  nasal. 

For  the  most  part  there  is  but  one  superior 
or  palpebral  branch,  though  sometimes  there 
are  two.  This  branch  is  destined  to  supply  the 
lower  eyelid,  and  is  denominated  the  inferior 
palpebral  nerve  ;  it  presents  some  variety  in  its 
mode  of  origin  and  its  course  ;  most  frequently 
it  does  not  separate  from  the  trunk  till  after  the 
latter  has  escaped  from  the  infraorbital  foramen; 
but  in  some  instances  it  does  so  within  the  in- 
fraorbital canal,  is  transmitted  through  a  dis- 
tinct canal,  and  escapes  into  the  face  through  a 
separate  foramen,  situate  internal  to  the  infra- 
orbital ;  it  ascends  inward  toward  the  lower 
lid,  in  front  of  the  inferior  margin  of  the  orbit ; 
in  its  ascent  it  is  situate  beneath  the  orbicularis 
palpebrarum,  to  which  it  gives  filaments,  which 
after  supplying  the  muscle  become  cutaneous, 
and  it  is  frequently  contained  in  a  superficial 
groove  on  the  superior  maxilla  ;  having  reached 
the  lid  it  divides  into  two  branches,  an  external 
and  an  internal.  The  external  runs  outward, 
through  the  lid,  toward  the  external  angle, 
supplies  its  structures  on  that  side,  and  anasto- 
moses with  filaments  of  the  portio  dura,  and  of 
the  inferior  palpebral  branches  of  the  lachrymal 
nerve.  The  internal  ascends  in  the  course  of  the 
original  nerve  toward  the  internal  canthus  of 
the  eye,  gives  a  filament  to  the  side  of  the  nose, 
which  communicates  with  the  naso-lobar  branch 
of  the  nasal  nerve,  supplies  the  lower  lid  at  its 
internal  part,  is  also  distributed  to  the  carun- 
cula  and  lachrymal  sac,  and  anastomoses  with 
a  filament  of  the  inferior  branch  of  the  infra- 
trochlear  nerve  described  in  the  account  of  that 
nerve.  It  sometimes  anastomoses  also  with 
the  portio  dura. 

When  there  is  a  second  palpebral  branch,  it 
takes  the  place  of  the  external  branch  of  the 
former,  which  in  such  case  is  denominated  the 
internal  inferior  palpebral,  and  the  second  the 
external.  It  perforates  the  levator  labii  supe- 
rioris  muscle ;  ascends  toward  the  external 
angle  of  the  eye,  beneath  the  orbicularis  palpe- 
brarum ;  and,  like  the  external  branch  of  the 
inferior  palpebral,  already  described,  supplies 

u 


290 


FIFTH  PAIR  OF  NERVES. 


the  structure  of  the  lid,  and  anastomoses  with 
the  portio  dura,  lachrymal,  and  malar  nerves, 
as  also  with  the  internal  palpebral. 

The  descending  or  labial  branches  are  the 
largest  and  the  most  numerous  ;  for  the  most 
part  they  are  three,  at  times  four.  They  de- 
scend to  the  upper  lip,  one  toward  its  middle, 
the  second  toward  its  intermediate,  and  the 
third  toward  its  outer  part,  the  commissure  of 
the  lips,  and  are  denominated  internal,  mid- 
dle, and  external;  they  are  situate,  all  at  first, 
beneath  the  levator  labii  superioris,  between  it 
and  the  levator  anguli  oris  or  canine  muscle; 
as  they  descend,  they  give  filaments  to  these 
muscles  and  to  the  parts  superficial  to  them ; 
and  they  pass  to  their  several  destinations,  the 
internal  between  the  levator  labii  and  the  de- 
pressor alas  nasi ;  the  middle  between  the  same 
muscles ;  and  the  external  superficial  to  the 
levator  anguli,  and  uncovered  by  the  levator 
labii ;  as  they  approach  the  lip  they  divide 
each  into  branches,  which  are  distributed  to 
the  structures  of  the  part  at  their  several  situa- 
tions ;  to  the  orbicularis  oris,  and  the  insertions 
of  the  other  muscles  of  the  lip,  to  the  integu- 
ment of  the  lip,  internal  and  external,  and  also 
to  the  labial  glands ;  they  all  communicate  to- 
gether, and  with  branches  of  the  portio  dura ; 
the  external  more  particularly  with  the  latter, 
as  also  with  the  neighbouring  branches  of  the 
fifth ;  the  internal  with  the  inferior  nasal ;  the 
external  with  the  inferior  labial  and  buccal 
nerves.  In  the  infraorbital  region,  the  branches 
of  the  superior  maxillary  are  crossed  by  and 
interlaced  with  those  of  the  portio  dura;  the 
latter  running  from  without  inward,  and  for  the 
most  part  superficial  to  the  former ;  but  also 
beneath  and  among  them,  and  even  forming 
loops  about  them ;  while  the  former  run  from 
above  downward,  and  are  principally  deeply 
seated.  In  consequence  of  this  diversity  in 
their  directions  and  the  numerous  anastomoses 
which  they  hold  with  each  other,  the  branches 
of  the  two  nerves  form  a  very  intricate  mesh  in 
that  region. 

In  some  Carnivora  filaments  of  the  facial 
branches  of  the  fifth  nerve  have  been  traced 
into  the  bulbs  of  the  hairs  of  the  whiskers  and 
the  tufts  with  which  they  are  furnished  ;  this 
is  remarkably  so  in  the  seal,  as  described  by 
Andral :  they  are  strongly  expressed  by  Rapp.* 

The  internal  or  nasal  branches  are,  for  the  most 
part,  two  ;  they  are  termed  superficial  nasal  by 
the  elder  Meckel,  and  distinguished  into  supe- 
rior and  inferior;  they  pass,  both,  inward  toward 
the  nose,  beneath  the  levator  labii  superioris, 
the  inferior  at  the  same  time  descending,  and 
having  reached  the  side  of  the  nostril  they  sub- 
divide. 

The  superior  is  the  smaller  of  the  two,,  and 
arises  frequently  from  a  branch  common  to  it 
and  the  internal  inferior  palpebral ;  it  divides 
into  three,  of  which  the  first,  the  uppermost,  is 
distributed  to  the  origin  of  the  levator  labii 
alaeque  nasi,  to  the  compressor  naris,  and  to  the 
integuments  on  the  dorsum  of  the  nose;  the 

*  Die  Verrichtungen  des  funften  Hirnnerven- 
paars. 


second,  the  middle,  to  the  compressor  naris 
and  also  to  the  integuments  of  the  nostril,  and 
the  third,  the  inferior,  to  the  compressor  naris, 
to  the  depressor  alae  nasi,  and  to  the  integu- 
ments of  the  ala. 

The  inferior  superficial  nasal,  the  larger  of 
the  two,  first  gives  occasionally  a  branch,  which 
ascends  to  the  eyelid ;  then  communicates  with 
the  superior,  and  having  reached  the  ala  of  the 
nose,  it  gives  off  numerous  ramifications  which 
are  distributed  to  the  levator  and  depressor  alae, 
to  the  integuments  of  the  inferior  part  of  the 
ala,  of  the  tip,  and  of  the  septum,  and  also  to 
the  upper  lip  ;  it  communicates  with  the  rami- 
fications of  the  naso-lobar  branch  of  the  nasal 
nerve,  of  the  internal  labial,  and  of  the  portio 
dura. 

The  third  division  of  the  fifth. — This  trunk 
has  been  denominated  by  Winslow,  on  account 
of  its  general  distribution,  the  inferior  maxillary 
nerve,  and  it  is  generally  known  by  that  appel- 
lation ;  yet  it  appears  to  the  writer  that  it 
would  have  been  much  better  had  that  title 
been  applied  only  to  that  portion  of  the  nerve 
which  enters  the  lower  jaw.  Such  is  the 
opinion  of  the  elder  Meckel,  who  observes  that 
this  use  of  the  epithet  leads  to  the  inconveni- 
ence that  the  branch  alluded  to  and  the  trunk 
of  the  nerve  may  be  easily  confounded.  It  is 
much  the  largest  of  the  three  divisions,  and 
differs  remarkably  from  the  other  two  in  its 
composition ;  they  are  both  single,  and  derived 
altogether  from  the  Gasserian  ganglion;  it  on 
the  contrary  is  composed  and  made  up  of  two 
portions,  one  derived  from  the  ganglion,  the 
other  not  connected  with  it ;  the  former  is  the 
largest  of  the  three  trunks  connected  with  the 
ganglion ;  it  is  attached  to  its  posterior  external 
extremity ;  at  its  attachment  it  is  cineritious 
and  very  wide,  but  as  it  proceeds  it  loses  that 
tint,  and  acquires  a  compressed  cylindrical 
form.  It  is  situate  external,  posterior,  and  in- 
ferior to  the  others,  and  its  course  within  the 
cranium  is  very  short  or  none,  for  from  the 
ganglion  it  enters  at  once  the  inferior  maxillary 
or  foramen  ovale  of  the  sphenoid  bone,  and 
escapes  from  the  cavity,  passing  downward,  for- 
ward, and  outward,  nearly  at  right  angles  with 
the  second  division  of  the  fifth.  Before  leaving 
the  cranium  it  is  joined,  as  the  first  and  second 
divisions  are,  by  a  filament  from  the  sympa- 
thetic, according  to  Munniks,  Laumonier,  and 
Bock* 

The  second  portion,  of  which  the  third 
division  is  composed,  is ,  the  lesser  packet  of 
the  fifth  itself;  this,  it  has  been  already  stated, 
does  not  join  the  ganglion,  but  passing  out- 
ward, beneath  that  body,  is  united  to  the  former 
portion  posteriorly,  in  the  foramen  ovale ;  it 
forms,  however,  but  a  small  proportion  of  the 
nerve,  that  part  which  is  attached  to  the  gan- 
glion exceeding  it  very  much  in  size.  At  its 
junction,  it  is  placed  posterior  to  the  other, 
but  it  immediately  spreads  out,  and  increases 
very  much  in  width,  and  at  the  same  time  is 
lapped  round  the  inner  side  of  the  ganglionic 
portion  so  as  to  get  before  it,  and  to  form  the 

*  Op.  cit.  and  Journ.  Compl. 


FIFTH  PAIR  OF  NERVES. 


291 


anterior  part  of  the  nerve  by  the  time  it  has 
escaped  from  the  cranium. 

The  third  division  of  the  fifth  nerve,  after  its 
escape  from  the  cranium,  is  situate  in  the 
superior,  posterior,  and  internal  part  of  the 
zygomatic  fossa;  it  is  placed  immediately  be- 
hind the  external  pterygoid  muscle,  before  and 
somewhat  internal  to  the  styloid  process  of  the 
sphenoid  bone,  internal  to  and  on  a  line  with 
the  anterior  margin  of  the  temporo-maxillary 
articulation,  and  external  to  the  Eustachian 
tube.  So  soon  as  the  inferior  maxillary  nerve 
has  entered  the  fossa,  it  gives  off,  immediately 
beneath  the  superior  wall  of  that  fossa,  a  set 
of  branches  remarkable  for  their  source  and 
destination  ;  they  proceed  from  the  front  of  the 
nerve ;  their  regular  number  is  five,  but  they 
present  variety  in  this  respect,  being  in  some 
instances  not  so  many  at  their  origin,  in  others 
amounting  to  six  ;  they  vary  also  in  the  mode 
in  which  they  arise ;  for  the  most  part  they 
are  given  off  separately  and  branch  off,  as 
rays,  from  the  nerve,  but  at  times  the  nerve 
divides  into  two  branches,  a  smaller  anterior 
one,  and  a  larger  posterior;  in  such  case  the 
anterior  divides  immediately  into  the  branches, 
which  otherwise  arise  from  the  nerve  itself. 
These  branches  are  the  masseteric,  the  deep 
temporals,  the  buccal,  and  the  pterygoid  nerves, 
and  they  are  ranged  in  succession  from  behind 
forward,  and  from  without  inward  ;  the  first  is 
external  and  posterior;  to  it  succeed  the  tempo- 
rals, then  the  buccal,  and  lastly  the  pterygoid. 

1 .  The  masseteric  branch  proceeds  from  the 
anteriorand  outer  part  of  the  nerve;  it  passes  out- 
ward, nearly  transversely,  beneath  the  superior 
wall  of  the  temporal  fossa,  and  in  front  of  the 
articular  surface  of  the  temporal  bone ;  it  crosses 
obliquely  over  the  external  pterygoid  muscle, 
at  its  outer  extremity,  between  the  muscle  and 
the  wall  of  the  fossa,  and  then  inclines  down- 
ward through  the  sigmoid  notch  of  the  lower 
jaw,  in  front  of  its  neck,  and  of  the  insertion  of 
the  external  pterygoid  muscle,  and  posterior  to 
the  coronoid  process  and  the  tendon  of  the 
temporal  muscle.  Having  traversed  the  notch 
it  descends  forward,  external  to  the  ramus  of 
the  jaw,  and  passing  between  the  two  portions 
of  the  masseter, divides  into  numerous  ramifica- 
tions, which  are  distributed  altogether  to  that 
muscle :  while  between  the  portions  of  the 
masseter,  it  inclines  from  its  posterior  toward 
its  anterior  margin,  and  its  terminating  filament 
can  be  traced  to  the  latter  at  the  inferior  part 
of  the  muscle.  This  branch  gives  off,  during 
its  course,  some  minor  branches  ;  while  in  front 
of  the  articulation  of  the  jaw  it  gives  one  or 
more  filaments  to  the  articulation ;  in  the  next 
place  it  gives  a  small  branch  to  the  posterior 
part  of  the  temporal  muscle,  and  lastly  it  fre- 
quently gives  off  the  external  or  posterior  deep 
temporal  nerve. 

2.  The  deep  temporal  branches  are  two;  they 
are  distinguished  into  posterior  and  anterior  or 
external  and  internal.  The  anterior  is  the 
larger.  They  present  varieties  in  their  num- 
ber and  mode  of  origin  ;  at  times  there  is  but 
one,  at  others  there  are  three  ;  in  some  instances 


they  arise  by  a  common  origin  ;  in  others,  and 
for  the  most  part,  separately,  and  in  others 
again  the  posterior  or  lesser  branch  is  given  off 
either  by  the  masseteric  or  the  buccal  nerve. 
They  both  pass  outward,  in  front  of  the  tem- 
poro-maxillary articulation,  between  the  exter- 
nal pterygoid  muscle  and  the  superior  wall  of 
the  zygomatic  fossa;  they  then  change  their 
direction  and  ascend  in  the  temporal  fossa,  be- 
tween the  muscle  and  the  surface  of  the  fossa, 
and  divide  into  branches,  which  attach  them- 
selves to  the  temporal  muscle,  on  its  deep  sur- 
face, and  are  distributed,  those  of  the  posterior 
to  its  posterior,  and  those  of  the  anterior  to  its 
middle  and  anterior  parts.  The  two  branches 
frequently  anastomose  with  each  other  as  they 
leave  the  zygomatic  fossa.  The  anterior  also 
frequently  communicates  with  or  receives  a 
branch  from  the  buccal  nerve,  and  by  one  of 
its  anterior  filaments  it  anastomoses  with  the 
nerve  resulting  from  the  junction  of  the  tempo- 
ral branches  of  the  lachrymal  nerve  and  the 
temporo-malar  branch  of  the  second  division  of 
the  fifth.  This  communication  between  the 
three  divisions  of  the  fifth  is  however,  accord- 
ing to  the  elder  Meckel,  subject  to  variety;  he 
states  that  he  has  seen  the  communicating 
branch  of  the  anterior  deep  temporal  at  times 
enter  the  orbit  either  through  the  malar  bone, 
or  through  the  spheno-maxillary  fissure,  and 
there  unite  with  the  conjoined  branch  of  the 
other  two. 

3.  The  buccal  nerve  is  the  largest  and  the 
principal  of  these  branches ;  it  arises  from  the 
front  of  the  inferior  maxillary  nerve,  next  in  or- 
der after  the  anterior  deep  temporal,  for  the  most 
part  a  distinct  and  single  branch  ;  but  it  is  not 
unusual  to  find  the  buccal  nerve  give  off  one  or 
both  of  the  deep  temporals,  or  in  rare  cases  all 
the  three  former  branches :  in  some  instances 
also  it  arises  double,  the  two  filaments,  of. 
which  it  is  then  composed,  being  separated  by 
a  portion  of  the  external  pterygoid  muscle.  It 
runs  downward  and  forward,  passing  at  first 
either  and  for  the  most  part  through  the  exter- 
nal or  between  the  two  pterygoid  muscles,  be- 
neath the  .external  and  external  to  the  internal; 
having  traversed  the  pterygoid  it  descends  in 
front  of  its  inferior  part,  internal  to  the  coronoid 
process  of  the  lower  jaw,  and  the  inferior  part 
of  the  temporal  muscle,  next  between  the  ten- 
don of  the  temporal  and  the  buccinator,  then 
between  the  anterior  margin  of  the  masseter 
and  the  latter  muscle,  and  finally  emerging 
from  between  them  it  inclines  toward  the  angle 
of  the  mouth,  superficial  to  the  buccinator  and 
beneath  the  dense  expansion  by  which  that 
muscle  is  covered.  During  its  descent  it  is 
immersed  in  the  fat  which  occupies  the  lower 
part  of  the  zygomatic  fossa.  The  ramifications 
which  it  gives  off  are  numerous;  first  while 
traversing  and  immediately  after  escaping 
from  the  pterygoid  it  gives  branches  to  the 
muscle ;  at  the  same  time  it  gives  off  a 
fasciculus  of  branches  which  pass  outward,  in 
front  of  the  external  pterygoid  to  the  internal 
surface  of  the  temporal  muscle,  at  its  inferior 
part ;  some  of  these  descend  with  the  muscle 

v  2 


292 


FIFTH  PAIR  OF  NERVES. 


toward  its  insertion,  and  are  distributed  to  it  at 
that  point,  others  ascend  in  the  temporal  fossa, 
between  the  muscle  and  the  bone,  penetrate  the 
muscle,  and  are  distributed,  along  with  the 
branches  of  the  anterior  deep  temporal,  with 
which  they  anastomose  freely,  to  the  muscle  at 
its  inferior  anterior  part.  In  the  next  place, 
while  between  the  masseter  and  the  buccinator, 
the  nerve  gives  off  backward  several  branches, 
three  or  four,  which  are  distributed  to  the  buc- 
cinator at  its  origin,  to  the  buccal  glands,  and 
to  the  membrane  of  the  mouth  ;  as  it  lies  upon 
the  last-named  muscle,  between  the  ramus  of 
the  jaw  and  the  angle  of  the  mouth,  it  gives 
filaments  to  it  at  its  middle  and  anterior  part, 
which,  like  the  former,  both  supply  the  muscle, 
pass  through  its  fibres,  and  are  distributed  also 
to  the  buccal  glands  and  membrane.  Finally, 
as  the  nerve  approaches  the  angle  of  the  mouth, 
it  divides  into  two,  occasionally  three,  branches; 
these  two  branches  pursue  the  direction  of  the 
nerve  toward  the  angle,  passing  beneath  the 
facial  vein  and  inclining,  one  upward,  the  other 
downward;  after  a  short  course  they  are  united 
both  to  branches  of  the  portio  dura,  the  inferior 
to  a  branch  of  the  inferior  or  cervico-facial  divi- 
sion, the  superior  to  one  of  the  superior  or  tem- 
poro-facial  division  of  that  nerve.  By  their 
union  they  form  conjoined  branches  or  loops, 
from  each  of  which  are  given  off  several  fila- 
ments to  the  muscles  of  the  mouth  at  their  in- 
sertion into  the  angle ;  from  the  superior,  more 
particularly,  to  the  buccinator,  the  zygomatic, 
and  levator  anguli ;  and  from  the  inferior  to  the 
buccinator  and  depressor  anguli  oris. 

4.  The  fifth  and  last  of  these  branches  is  the 
pterygoid;  it  is  the  smallest  of  them,  and 
arises  from  the  anterior  internal  part  of  the 
trunk ;  it  passes  inward  and  downward,  be- 
hind the  external  pterygoid,  and  then  between 
the  internal  pterygoid  and  circumtlexus  palati 
muscles ;  it  gives  a  filament  of  some  size  to 
the  latter  muscle,  and  then  entering  into  the 
internal  pterygoid  at  its  upper  extremity,  it  is 
consumed  altogether  in  that  muscle. 

The  external  pterygoid  also,  at  times,  but 
not  uniformly,  receives  a  distinct  filament  from 
the  trunk ;  when  present  it  arises  from  the 
front  of  the  nerve,  beneath  the  buccal  branch, 
and  passes  forward  directly  to  the  muscle,  in 
which  it  is  consumed.  The  constitution  of 
these  branches  is  peculiar,  and  is  a  matter 
of  much  interest:  involving  physiological  ques- 
tions, this  subject  is  deferred  to  another  oc- 
casion. 

In  consequence  of  its  connection  with  the 
third  division  of  the  fifth,  and  more  particularly 
with  the  lesser  packet  of  the  nerve,  this  seems 
a  fit  place  to  advert  to  the  ganglion  discovered 
by  Arnold,  and  by  him  denominated  Otic 
or  auricular,  of  which  the  following  sketch 
has  been  taken  from  his  own  account.  It 
is  situate  at  the  inner  side  of  the  third  branch 
of  the  fifth,  some  lines  beneath  the  foramen 
ovale,  at  the  part  where  the  deep  temporal, 
the  masseteric,  and  the  buccal  nerves  are  de- 
tached from  the  same  side,  and  a  little  above 
the  origin  of  the  superficial  temporal  nerve : 


its  posterior  part  touches  the  middle  meningeal 
artery,  and  the  internal  the  internal  pterygoid 
muscle  :  an  abundant  adipose  tissue  surrounds 
it :  its  form  is  not  altogether  regular,  however 
it  approaches  to  an  oval,  flattened  internally 
and  externally.  It  is  united  to  the  trunk 
of  the  third  division  not  merely  by  cellular 
tissue,  but  by  many  filaments,  which  enter 
into  the  formation  of  the  ganglion ;  these 
filaments,  which  come  solely  from  the  lesser 
portion  of  the  nerve,  are  mostly  extremely 
short,  and  can  only  be  observed  when  we 
try  to  separate  the  ganglion  from  the  trunk  ; 
but  in  cases  where  the  ganglion  is  situate 
rather  distant  from  the  nerve,  the  filaments 
are  of  course  longer  and  can  be  more  easily 
observed.  With  regard  to  the  branches  of 
the  third  division,  the  pterygoid  nerve  espe- 
cially is  in  very  intimate  connection  with  the 
otic  ganglion,  so  that  in  a  superficial  examina- 
tion it  appears  as  if  it  arose  from  it ;  but, 
in  a  more  accurate  investigation,  it  is  clear 
that  this  nerve  soon  after  its  origin  penetrates 
through  a  part  of  the  substance  of  the  ganglion 
and  takes  up  some  of  it :  the  slender  branch, 
which  ramifies  in  the  tensor  palati,  is  likewise 
in  very  intimate  relation  with  this  ganglion, 
and  distinguishes  itself  from  the  other  branches 
by  its  reddish  appearance.  The  ganglion  thus 
communicates  with  the  lesser  packet  of  the 
fifth  :  it  also  communicates  with  the  glosso- 
pharyngeal and  with  the  facial  and  auditory 
nerves  by  means  of  the  nervus  tympanicus. 
But,  the  ganglion  being  a  body  which  is  to 
be  regarded  as  distinct  from  the  fifth  nerve, 
and  not  part  of  it,  a  further  pursuit  of  its 
connections  and  properties  would  be  here  out 
of  place.    See  Svmpathetic  Nerve. 

The  third  division  of  the  fifth  descends  from 
the  foramen  ovale,  outward  into  the  zygomatic 
fossa,  posterior  to  the  external  pterygoid  muscle, 
before  the  superior  part  of  the  levator  palati, 
and  internal  and  parallel  to  the  middle  me- 
ningeal artery.  After  a  course  of  half  an  inch 
from  the  foramen,  it  divides  for  tiie  most  part 
into  two  large  branches,  an  anterior  internal 
one  destined  to  the  tongue,  denominated  the 
Ungual  branch,  and  an  external  posterior  one, 
which  is  transmitted  through  the  inferior  max- 
illary canal,  and,  escaping  from  this,  through 
the  mental  foramen,  is  distributed  finally  to 
the  muscles  and  integuments  of  the  chin ;  this 
second  branch  is  called  inferior  dental,  or 
inferior  maxillary  nerve ;  the  latter,  as  has 
been  already  intimated,  appears  much  the 
more  appropriate  appellation. 

The  first  branch  bears,  very  generally,  the 
name  of  gustatory  nerve  from  its  presumed 
connection  with  the  sense  of  taste;  but,  since 
the  opinion  that  it  is  the  nerve  in  which  the 
sense  of  taste  resides  has  been  brought  into 
question,  and  since,  as  will  appear  by-and- 
bye,  it  is  at  least  certainly  not  the  sole  nerve 
of  that  sense,  it  is  obvious  that  that  name 
should  be  discontinued. 

The  manner  in  which  the  third  division 
finally  divides  is  not  always  such  as  has  been 
described  :  in  some  instances  it  separates  fairly 


FIFTH  PAIR  OF  NERVES. 


293 


into  three  branches,  viz.  the  lingual,  the  inferior 
maxillary,  and  the  superficial  temporal,  and 
such  is  the  mode  of  division  mentioned  by 
the  elder  Meckel.  The  writer  has  before  him 
an  instance  of  another  mode  ;  the  inferior 
maxillary  arises  by  two  roots,  and  the'  original 
trunk  divides  into  two  parts;  one  common  to 
the  lingual,  and  one  root  of  the  maxillary ; 
the  other  to  the  superficial  temporal  and  the 
other  root :  the  superficial  temporal  is  thus, 
in  this  instance,  equally  an  original  branch 
as  the  others,  and  is  connected  to  the  maxillary 
by  a  filament,  which  it  gives  off  soon  after 
its  origin,  while  the  maxillary  is  also  connected 
in  the  usual  mode  to  the  lingual :  the  maxillary 
artery,  however,  passes  through  the  loop  formed 
by  the  two  roots  of  the  former  nerve. 

The  length  of  the  third  division  from  the 
ganglion  to  its  bifurcation  is  about  three  fourths 
of  an  inch,  one  fourth  contained  within  the 
bone  during  its  escape  from  the  cranium,  and 
the  other  two  between  the  aperture  externally 
and  the  division.  When  it  divides  into  two, 
the  branches  are,  at  times,  of  the  same  size, 
but  for  the  most  part  the  inferior  maxillary 
is  the  larger;  they  descend  at  first  in  close 
apposition  with  each  other,  but  as  they  proceed 
they  gradually  separate,  the  lingual  branch 
inclining  inward  and  forward,  the  inferior 
maxillary  outward,  in  the  course  of  the  original 
nerve,  in  order  to  gain  the  aperture  of  the 
dental  canal ;  they  thus  leave  between  them 
an  angular  interval,  acute  above,  through 
which  the  internal  maxillary  artery  for  the  most 
part  passes.  In  their  descent  they  cross,  at 
right  angles,  the  artery  internal  to  the  origin 
of  the  middle  meningeal  branch  :  in  doing  so 
either  they  pass  both  behind  the  vessel,  or  the 
lingual  branch  passes  before,  and  the  inferior 
maxillary  behind  it.  The  two  nerves  are  most 
frequently  connected,  soon  after  their  origin, 
by  a  short  and  delicate  branch,  which  passes 
from  the  inferior  maxillary  to  the  lingual,  and 
forms,  with  the  nerves,  a  triangle,  through 
which  the  artery  passes  in  those  instances  in 
which  the  lingual  descends  before  it. 

The  nerves  are  situate  internal  to  the  neck 
and  ramus  of  the  jaw,  between  the  pterygoid 
muscles,  posterior  and  inferior  to  the  external, 
external  and  anterior  to  the  internal  ;  and  they 
are  contained  in  a  triangular  space  included 
between  the  two  muscles  and  the  jaw,  bounded 
superiorly  by  the  external,  beneath  and  in- 
ternally by  the  internal  pterygoid,  and  externally 
by  the  jaw;  through  this  space  they  pass  from 
above  downward,  the  lingual  from  behind 
forward,  and  from  without  inward,  the  maxil- 
lary from  within  outward,  toward  the  aperture 
of  the  dental  canal,  and  holding  the  mutual 
relation  already  indicated, — the  lingual  anterior 
and  internal,  the  maxillary  posterior  and  ex- 
ternal. 

Before  pursuing  these  branches  of  the  third 
division  further,  it  will  be  well  to  describe 
the  superficial  temporal  nerve.  This  branch 
has  been  viewed  differently  by  different  autho- 
rities ;  by  some  it  is  accounted  one  of  the 
former  set,  the  superior  anterior  branches  of 
the  third  division  ;  by  Meckel  it  is  described 


as  one  of  three,  into  which  the  continuation 
of  the  nerve  divides.  It  arises  for  the  most 
part  by  two,  and  in  some  instances  by  three, 
roots  ;  a  larger  one  from  the  inferior  dental 
nerve,  and  a  smaller  from  the  trunk  of  the 
third  division  itself,  given  off  at  the  same 
time  with  its  superior  branches,  and  deri- 
ved from  the  same  source;  the  two  roots 
forming  together  a  loop,  through  which  the 
middle  meningeal  artery  ascends:  in  conse- 
quence of  this  mode  of  origin  it  appears  better 
to  describe  it  thus  separately,  and  not  to  refer 
it  to  either  of  the  sets  described.  It  has, 
however,  been  already  explained  that  in  some 
cases  it  appears  to  be  an  original  branch  of 
the  third  division,  one  of  three  into  which  it 
finally  divides. 

The  nerve  runs  outward,  backward,  and 
somewhat  upward,  behind  the  external  ptery- 
goid muscle,  toward  the  back  of  the  neck  of 
the  lower  jaw ;  it  then  passes  behind  it  and 
the  condyle,  between  them  and  the  auditory 
canal,  traversing  the  posterior  part  of  the 
glenoidal  cavity  of  the  temporal  bone,  and 
imbedded  in  the  process  of  the  parotid  gland, 
which  occupies  it. 

The  superficial  temporal  nerve,  while  within 
the  ramus  of  the  jaw,  pursues  a  course  nearly 
the  reverse  of  that  of  the  trunk  of  the  internal 
maxillary  artery  in  the  first  part  of  its  course. 
At  first  it  is  situate  before  the  tensor  palati 
muscle,  between  it  and  the  external  pterygoid  ; 
then  it  passes  between  the  internal  lateral 
ligament  of  the  maxillary  articulation  and  the 
neck  of  the  jaw,  situate  at  the  same  time 
above  and  in  contact  with  the  artery  ;  and 
lastly,  it  is  situate  behind  the  condyle  of  the 
jaw,  between  it  and  the  meatus  auditorius, 
and  involved  in  the  parotid. 

The  nerve  gives  off  numerous  branches ; 
when  it  has  reached  the  situation  last  described, 
it  breaks  up  at  once  into  a  leash  of  branches, 
which  pass  off  in  different  directions :  of  these 
two,  at  times  only  one,  are  destined  for  the 
interior  of  the  meatus  auditorius  ;  they  ascend 
toward  the  canal,  become  attached  to  its  ex- 
terior, and  pass  through  the  fibrous  structure  of 
the  tube,  close  to  its  connection  with  the  osseous 
portion  :  having  thus  gained  its  interior,  they 
are  distributed  to  its  lining  membrane,  its 
sebaceous  follicles,  and  the  membrane  of  the 
tympanum.  Before  entering  the  tube  they  give 
some  delicate  filaments  to  its  exterior;  these 
branches  may  be  called  the  internal  auricular. 

Others,  the  smallest  which  the  nerve  gives 
off,  descend  along  the  external  carotid  artery, 
are  in  part  distributed  to  the  parotid  gland, 
and  establish  upon  the  artery  a  manifest  com- 
munication with  branches  of  the  sympathetic. 
Its  next  branches,  two  in  number,  pass  out- 
ward through  the  substance  of  the  parotid, 
behind  the  neck  of  the  jaw;  one  external  or 
superficial,  the  other  internal  to  the  temporal 
artery;  and  turning  forward  round  the  posterior 
margin  of  the  jaw,  either  they  both,  having 
given  some  fine  ramifications  to  the  gland, 
join  the  temporo-facial  branch  of  the  portio 
dura,  immediately  before  its  division,  or  one 
of  them  joins  the  facial  branch  of  the  tern- 


294 


FIFTH  PAIR  OF  NERVES. 


poro-facial,  while  the  other  continues  forward, 
upon  the  face,  below  the  zygoma,  and  deeper 
than  the  branches  of  the  temporo-facial :  it 
divides  into  numerous  long  filaments,  of  which 
some  join  both  branches  of  the  temporo-facial ; 
others  are  distributed  superficially  upon  the 
side  of  the  face  beneath  the  zygoma  and  upon 
the  malar  region,  and,  ascending  over  the 
former  part,  to  the  inferior  anterior  part  of 
the  temple,  as  far  forward  as  the  margin  of 
the  orbit.  These  may  be  called  the  commu- 
nicating branches,  in  consequence  of  the  re- 
markable and  important  communication  which 
they  establish  with  the  portio  dura. 

The  next  may  be  called  external  auricular  ; 
they  ascend  to  the  anterior  part  of  the  car- 
tilaginous tube  of  the  ear,  concealed  by  the 
temporal  artery,  attach  themselves  to  the  tube 
in  front,  and  are  distributed  to  the  integuments 
of  the  concha. 

Lastly,  the  superficial  temporal  nerve 
emerges  from  the  parotid  gland,  beneath  the 
root  of  the  zygoma,  between  the  condyle  of 
the  jaw  and  the  cartilaginous  tube  of  the  ear, 
in  company  with  the  temporal  artery,  and 
concealed  by  it :  it  then  changes  its  course 
and  ascends  with  the  artery  behind  the  zygoma 
and  in  front  of  the  ear,  upon  the  temple :  there 
it  emerges  from  beneath  the  artery,  posterior 
to  it,  and  divides  into  branches,  which  become 
subcutaneous,  run  superficial  to  the  fascia  and 
the  artery  beneath  the  subcutaneous  cellular 
structure,  and  are  ultimately  distributed  to  the 
integument  of  the  temple :  their  number  is 
two  or  three ;  they  may  be  distinguished  into 
anterior,  middle,  and  posterior,  and  they  are 
destined  to  the  corresponding  parts  of  the 
temple :  they  correspond  in  their  course,  but 
by  no  means  regularly  or  strictly  so,  to  the 
branches  of  the  temporal  artery,  from  which 
they  are  separated  by  the  fascia. 

Of  the  two  terminal  branches  of  the  third 
division,  the  larger  one,  the  inferior  maxil- 
lary or  dental,  descends  outward  to  the  upper 
orifice  of  the  inferior  maxillary  canal.  In 
its  course  it  passes  always  behind  the  inter- 
nal maxillary  artery,  and  soon  glides  between 
the  internal  lateral  ligament  of  the  temporo- 
maxillary  articulation,  and  the  ramus  of  the 
jaw,  descending  in  front  of  the  anterior  margin 
of  the  ligament,  which  thus  becomes  interposed 
between  it  and  the  lingual  branch,  and  also  be- 
tween it  and  the  internal  pterygoid  muscle,  from 
the  pressure  of  which  the  ligament  is  considered 
to  protect  it.  In  that  situation  it  is  joined  by  the 
inferior  dental  artery,  a  branch  of  the  internal 
maxillary  given  off  between  the  ligament  and 
the  jaw,  which  accompanies  it  through  its  further 
course.  It  next  enters  the  canal,  and  is  trans- 
mitted through  it  downward,  forward,  and 
inward  toward  the  chin,  beneath  the  sockets  of 
the  teeth;  having  reached  the  termination  of 
the  canal,  it  is  reflected  upward  and  outward 
through  the  mental  foramen,  and  escapes  from 
the  canal  upon  the  lateral  and  superficial  surface 
of  the  jaw,  at  either  side  of  the  chin;  at  its 
exit  it  is  beneath  the  second  bicuspid  tooth  of 
the  lower  jaw,  and  covered  by  the  muscles  of 
the  lip  :  it  then  terminates  by  dividing  into  two 


branches,  called  inferior  labial  nerves,  external 
and  internal.  The  branches  of  the  inferior 
maxillary  are  as  follow : — presently  after  its 
origin  it  gives  off  the  branch  by  which  the 
lingual  branch  and  the  inferior  maxillary  are 
connected,  and  which  completes  the  loop 
through  which  the  internal  maxillary  artery 
passes ;  also  the  branch  which  forms  a  root  of 
the  superficial  temporal  nerve.  Next,  imme- 
diately before  entering  the  dental  canal,  it  gives 
off  a  long  slender  branch,  denominated  mylo- 
hyoid nerve  ;  this  branch  descends  forward  and 
inward  along  the  inside  of  the  ramus  of  the 
jaw,  between  it  and  the  internal  pterygoid 
muscle,  and  lodged  in  a  groove  upon  the  sur- 
face of  the  bone,  which  leads  in  the  same 
direction,  and  is  occasionally  in  part  a  bony 
canal ;  it  is  covered  in  the  groove  by  a  prolon- 
gation of  the  internal  lateral  ligament,  and 
escapes  from  it  inferiorly  in  front  of  the  insertion 
of  the  internal  pterygoid  muscle  and  beneath 
the  lingual  branch;  it  then  passes  beneath  or 
external  to  the  mylohyoid  muscle,  between  the 
submaxillary  gland  and  the  internal  surface  of 
the  jaw,  gains  the  surface  of  the  muscle  itself 
and  runs  forward  and  inward  above  the  super- 
ficial portion  of  the  gland,  between  it  and  the 
muscle,  and  accompanied  by  the  submental 
artery;  finally,  it  divides  into  a  leash  of  branches. 
Of  these  one  is  sometimes  destined  to  the  sub- 
maxillary gland ;  two  or  three  are  distributed 
to  the  mylohyoid  muscle;  another  to  the  anterior 
belly  of  the  digastric,  and  the  last  passes  first 
between  the  anterior  belly  of  the  digastric  and 
the  mylohyoid,  gives  filaments  to  the  muscles 
in  its  passage,  then  ascends  upon  the  chin 
internal  to  the  belly  of  the  digastric,  and  is 
consumed  in  the  depressor  labii  muscle. 

The  next  branches  of  the  nerve  are  those 
which  are  given  off  by  it  while  within  the 
inferior  maxillary  canal :  they  have  two  desti- 
nations, viz.  the  roots  and  periosteum  of  the 
teeth  and  the  gum  of  the  lower  jaw.  During 
its  course  through  the  canal  the  nerve  gives  off 
several  long,  slender  branches,  which  run  for 
some  distance  within  the  canal,  ascend  thence 
through  the  bone  beneath  and  on  either  side  of 
the  roots  of  the  teeth,  ramify  as  they  proceed, 
and  distribute  their  ramifications  to  the  desti- 
nations which  have  been  mentioned.  The 
author  has  never  found  these  branches  as  they 
are  for  the  most  part  represented,  viz.  short 
single  filaments  ascending  almost  directly  into 
the  several  fangs  of  the  teeth :  they  are  deci- 
dedly less  remarkable  and  less  numerous  in  the 
old  subject  after  the  fall  of  the  teeth  than  in 
the  young.  Again,  at  the  mental  foramen,  and 
immediately  before  its  escape  from  the  canal, 
the  nerve  gives  off  a  more  considerable  branch, 
denominated  by  Cruveilhier  dentaire  incisif, 
which  is  continued  through  the  jaw  toward  the 
symphysis  beneath  the  canine  and  incisor 
teeth,  and  distributed  to  them.  The  former 
set  supplies  the  posterior  molar  teeth.  Accord- 
ing to  the  general  opinion  the  nerves  of  the 
teeth  enter  the  fangs  through  the  apertures 
in  their  extremities,  and  are  transmitted  through 
them  into  the  bodies  of  the  teeth,  to  be  con- 
sumed in  the  pulp  and  the  structure  of  the 


FIFTH  PAIR  OF  NERVES. 


295 


leeth  themselves.  J.  Hunter,  however,  has 
stated  in  his  work  on  the  teeth,  that  he  has 
never  succeeded  in  tracing  nerves  into  the  fangs, 
and  the  experience  of  the  writer,  so  far  as  it 
extends,  tends  to  confinn  the  doubt  thus  ex- 
pressed; he  has  frequently  traced  the  filaments 
to  the  structure  at  the  root  of  the  fang,  but 
never  into  the  fang,  and  in  the  jaw  of  the  fcetal 
calf  they  may  be  found  distributed  in  number 
upon  the  membrane  of  the  pulp,  but  he  has 
not  been  able  to  follow  them  into  the  pulp 
itself. 

The  filaments  sent  into  the  gums  from  the 
dental  nerves,  superior  as  well  as  inferior, 
traverse  the  alveolar  arch,  escape  from  the  bone 
upon  its  gingival  aspect,  and  at  once  enter  the 
gum  :  they  are  well  represented  by  Arnold. 

The  final  branches  of  the  inferior  maxillary 
nerve  are  the  inf  erior  labial,  internal  and  exter- 
nal. Of  these  the  internal  is  the  larger;  it 
ascends  toward  the  mouth,  inclining  inward, 
and  breaks  up  into  a  great  number  of  ramifica- 
tions, which  are  distributed  to  the  depressor 
labii  inferioris,  the  depressor  anguli  oris,  the 
orbicularis,  and  the  levator  menti,  also  to  the 
integument  and  internal  membrane  of  the  lip, 
and  to  the  labial  glands;  they  anastomose  with 
branches  of  the  inferior  division  of  the  portio 
dura.  The  external  inclines  toward  the  angle 
of  the  mouth ;  it  also  gives  off  a  great  number 
of  ramifications,  distributed  to  the  depressor 
anguli,  the  orbicularis,  and  the  insertion  of  the 
muscles  at  the  angle,  the  integument,  and 
internal  membrane  of  the  lip,  and  the  labial 
glands;  it  also  anastomoses  with  branches  of 
the  portio  dura. 

The  Ungual  branch  of  the  third  division. — 
The  situation  and  relative  size  and  position  of 
the  lingual  and  inferior  maxillary  branches  in 
the  first  part  of  their  course,  have  been  already 
described.  Having  crossed  the  internal  maxil- 
lary artery,  the  lingual  branch  pursues  its  course 
downward,  forward,  and  inward,  passing  first 
between  the  pterygoid  muscles  in  the  manner 
described,  and  then  between  the  internal  ptery- 
goid and  the  ramus  of  the  jaw,  until  it  has 
reached  the  anterior  margin  of  that  muscle; 
during  this  part  of  its  course  it  is  at  first 
separated  from  the  inferior  maxillary  nerve  by 
the  internal  lateral  ligament,  which  is  placed 
between  them,  the  lingual  branch  internal,  the 
maxillary  external  to  it,  and  afterward  it  is 
situate  anterior  and  superior  to  the  mylohyoid 
branch  of  the  maxillary.  Having  reached  the 
margin  of  the  pterygoid  it  emerges  from  between 
the  muscle  and  the  jaw,  immediately  behind 
the  posterior  extremity  of  the  mylohyoid  ridge, 
and  enters  into  the  digastric  or  submaxillary 
space,  in  which  it  is  among  the  parts  most 
deeply  situate;  within  this  space  it  continues  to 
run  forward  and  inward,  until,  at  the  anterior 
extremity,  it  attaches  itself  to  the  under  surface 
of  the  tongue,  and  is  prolonged  by  one  of  its 
branches  to  the  extremity  of  that  organ.  During 
its  course  through  the  digastric  space,  it  is  at 
first  left  uncovered  by  the  muscles  inferiorly, 
and  in  the  interval  between  the  margin  of  the 
pterygoid  and  that  of  the  mylohyoid,  where  it 
is  situate  betwee»  the  mucous  membrane  of 


the  mouth  and  the  posterior  extremity  of  the 
submaxillary  gland ;  it  then  passes  internal  to 
the  mylohyoid  muscle,  between  it  and  the 
stylo-glossus,  hyo-glossus,  and  genio-glossus, 
and  is  at  the  same  time  contained  in  a  triangu- 
lar or  wedge-shaped  space,  the  base  of  which 
is  above  and  the  apex  below ;  this  space  is 
bounded  above  by  the  mucous  membrane  of 
the  mouth,  externally  by  the  mylohyoid  muscle, 
and  internally  by  the  hyo-glossus,  stylo-glossus, 
and  genio-glossus  muscles.  In  it  are  contained 
the  sublingual  gland,  the  deep  process  of  the 
submaxillary  and  the  duct  of  that  gland  with 
the  lingual  branch  of  the  fifth  and  the  ninth 
nerves;  in  the  anterior  part  and  superiorly, 
immediately  beneath  the  mucous  membrane, 
is  situate  the  sublingual  gland ;  at  the  posterior 
and  rather  inferiorly  the  deep  process  of  the 
submaxillary ;  while  the  nerves  and  the  duct 
are  placed  at  the  posterior  or  external  part  of 
the  lingual  branch  of  the  fifth  above,  imme- 
diately beneath  the  mucous  membrane;  the 
ninth  below,  along,  and  above  the  cornu  of 
the  os  hyoides,  and  the  duct  between  the 
nerves;  but  as  the  three  parts  pass  forward, 
the  duct  and  lingual  branch  cross  each  other, 
the  nerve  descending,  the  duct  ascending  be- 
tween the  nerve  and  the  hyo-glossus,  and  in 
consequence  of  this  circumstance,  at  the  ante- 
rior part  of  the  space,  the  duct  is  superior,  the 
lingual  branch  is  intermediate,  and  the  ninth 
nerve  is  below.  At  first  the  lingual  branch  is 
above  the  deep  process  of  the  submaxillary 
gland,  then  it  is  situate  internal  and  superior  to 
it,  external  and  inferior  to  the  duct;  as  it  pro- 
ceeds, it  is  beneath  the  sublingual  gland,  and, 
lastly,  it  ascends  internal  to  that  gland,  between 
it  and  the  genio-glossjj^4e£e*der  to  reach  the 
tongue.  j\s\^*~  ^Sfir 

At  the  posterior  part  of  the  space,  the  nerve 
is  immediately  beneath  the  mucous  membrane; 
as  it  proceeds  it  descends  from,  but  toward 
the  anterior  part  again  ascends,  and  is  in  con- 
tact with  the  membrane  as  it  becomes  attached 
to  the  tongue. 

Having  reached  the  anterior  margin  of  the 
hyo-glossus  the  nerve  breaks  up  into  three 
branches,  posterior,  middle,  and  anterior.  Of 
these  the  posterior  is  the  shortest,  and  ascends 
almost  directly ;  the  middle  runs  upward  and 
forward,  and  the  anterior,  which  is  much 
longer  than,  and  at  the  same  time  inferior  to 
the  others,  almost  directly  forward,  along  the 
under  surface  of  the  tongue,  between  the  genio- 
glossus  and  the  stylo-glossus ;  the  former 
muscle  internal,  the  latter  external  to  it.  In 
its  course  beneath  the  tongue  it  is  accompanied 
by  the  ranine  artery,  which  joins  it  at  the 
anterior  margin  of  the  hyo-glossus,  and  is 
situate  inferior  to  it,  immediately  above  the 
mucous  membrane. 

The  lingual  nerve  does  not  give  off  many 
branches  in  the  first  part  of  its  course :  soon 
after  its  origin  it  receives  the  branch  of  com- 
munication, by  which  the  inferior  dental  nerve 
is  connected  to  it.  About  the  same  point  or 
presently  after  it  is  also  joined  by  the  chorda 
tympani.  The  uncertainty  which  has  prevailed 
with  regard  to  the  source  of  this  nerve  renders 


296 


FIFTH  PAIR  OF  NERVES. 


a  more  particular  account  of  it  necessary  than 
would  otherwise  be  required.  The  chorda  tym- 
pani — a  delicate  filament — is  given  offfrom  the 
portio  dura  shortly  before  that  nerve  escapes 
from  the  aqueduct  of  Fallopius,  behind  and  be- 
low the  tympanum  :  it  passes  upward  and  for- 
ward toward  the  tympanum,  contained  in  a  spe- 
cial canal  of  the  bone,  and  having  reached  the 
back  of  the  chamber  it  emerges  from  its  posterior 
wall  through  a  small  aperture  beneath  the  base 
of  the  pyramid;  it  then  attaches  itself  to  the 
outer  wall  of  the  tympanum  and  crosses  it 
toward  the  anterior,  having  first  received*  a 
delicate  filament  from  the  sympathetic,  and 
running  forward,  upward,  and  outward.  During 
its  course  from  the  posterior  to  the  anterior 
wall  it  is  situate  at  first  beneath  the  short  cms 
of  the  incus,  then  between  the  long  crus  of 
the  incus  and  the  superior  part  of  the  handle 
of  the  malleus,  to  which  it  is  connected  by  the 
lining  membrane  of  the  tympanum.  Having 
ascended  above  the  internal  muscle  of  the 
malleus  it  changes  its  direction  and  runs  down- 
ward, forward,  and  inward  along  the  superior 
anterior  part  of  the  circumference  of  the  mem- 
brana  tympani,  until  it  has  reached  the  anterior 
wall  of  the  chamber,  from  which  it  goes  out 
through  the  Glaserian  fissure,  along  the  tendon 
of  the  anterior  muscle  of  the  malleus.  It  is 
throughout  excluded  from  the  interior  of  the 
tympanum  by  the  lining  membrane,  which  is 
connected  to  it  upon  that  side ;  it  is  therefore 
incorrect  to  say  that  it  crosses  the  chamber. 
After  its  escape  from  the  tympanum  the  nerve 
continues  to  descend  forward  and  inward  in 
front  of  the  levator  palati  muscle,  and  after  a 
course  from  three-fourths  of  an  inch  to  an  inch 
long  it  is  attached  at  a  very  acute  angle  to  the 
back  of  the  lingual  branch,  becomes  inclosed 
in  the  same  sheath  with  the  nerve,  and  con- 
tinues connected  with  it  altogether  until  the 
nerve  has  reached  the  posterior  extremity  of 
the  submaxillary  gland :  at  that  point  the 
chorda  tympani  divides  into  two  parts,  one  of 
which  is  despatched  to  the  submaxillary  gan- 
glion, and  the  other  continued  along  with  the 
lingual  branch.  By  somef  it  is  stated  that  it 
separates  from  the  nerve  at  the  ganglion,  and 
is  altogether  ununited  to  it;  this,  however,  is 
incorrect.  During  its  descent  in  company  with 
the  lingual  branch  there  may  be  observed, 
upon  particular  examination  of  the  conjoined 
trunk,  a  communication  and  identification  be- 
tween the  nervous  matter  of  the  two  nerves. 

Originally  the  chorda  tympani  was  regarded 
as  either  a  recurrent  filament  of  the  lingual 
branch  of  the  fifth  or  a  branch  of  the  portio 
dura  :  afterwards  the  opinion  was  adopted  that 
it  was  not  a  branch  of  the  portio  dura,  but  the 
cranial  superficial  petrous  branch  of  the  Vidian 
nerve,  which,  instead  of  uniting  and  being  iden- 
tified with  the  portio  dura,  descended  through 
the  aqueduct  merely  in  apposition  with  it  or 
within  the  same  sheath,  separated  from  it  again 
before  the  nerve  escaped  from  the  aqueduct, 
and  constituted  the  chorda  tympani.  This  view 

*  Bock,  Meckel  junior,  Cloquet. 
t  Cloquet. 


of  the  nature  of  the  chord,  suggested  first,  as  it 
would  appear,  by  J.  Hunter,  has  been  advo- 
cated also  by  Cloquet  and  Hirzel,  and  is  at 
present  entertained  by  many  in  this  country  at 
least;  it  has  been  objected  to  by  Arnold,  and 
another  has  been  advanced  by  him  from  obser- 
vations made  upon  the  calf  and  the  human 
subject.  Hunter's  account  of  the  connection 
of  the  nerves  is  as  follows  :  "  This  nerve  com- 
posed of  portio  dura  and  the  branch  of  the  fifth 
pair  sends  off,  in  the  adult,  the  chorda  tympani 
before  its  exit  from  the  skull,  and  in  the  foetus, 
immediately  after.  The  termination  of  the 
branch  called  chorda  tympani  I  shall  not  de- 
scribe, yet  I  am  almost  certain  it  is  not  a 
branch  of  the  seventh  pair  of  nerves,  but  the 
last-described  branch  from  the  fifth  pair,"  i.  e. 
the  Vidian,  "  for  I  think  I  have  been  able  to 
separate  this  branch  from  the  portio  dura,  and 
have  found  it  lead  to  the  chorda  tympani ;  per- 
haps is  continued  into  it ;  but  this  is  a  point 
very  difficult  to  determine,  as  the  portio  dura 
is  a  compact  nerve,  and  not  so  fasciculated  as 
some  others  are."*  According  to  Arnold,  nei- 
ther of  the  previous  opinions  is  correct;  but 
the  petrous  nerve  anastomoses  with  filaments 
of  the  facial  nerve,  principally  the  external, 
with  which  it  forms  a  gangliform  swelling  at 
the  place  at  which  the  nerve  receives  it ;  and 
the  branch  which  forms  the  corda  tympani 
arises  from  the  gangliform  swelling  of  the  facial 
nerve,  and  holds  in  an  intimate  manner  to  the 
petrous  nerve ;  however  it  is  not  to  be  consi- 
dered a  continuation  of  the  latter :  it  is  united, 
during  its  course,  to  the  facial  nerve  by  several 
filaments,  and  consequently  the  chorda  tympani 
ought  to  be  regarded  neither  as  a  branch  of  the 
facial  nerve  nor  as  a  continuation  of  the  petrous 
nerve,  but  as  one  composed  of  both.f  Cru- 
veilhier  J  maintains  that  the  chorda  tympani  is 
not  a  prolongation  of  the  Vidian  nerve,  but  he 
assigns  no  reason  for  his  opinion.  The  ques- 
tion at  issue  probably  cannot  be  decided  from 
the  human  subject:  the  impediment  opposed 
to  its  satisfactory  determination  by  the  density 
of  the  facial  nerve,  as  admitted  by  Hunter,  and 
by  the  manner  in  which  the  facial  and  the 
Vidian  nerves  are  in  it  blended  together  at  their 
junction,  will  hardly  permit  the  point  being 
accurately  ascertained ;  but  the  same  diffi- 
culty does  not  exist  in  other  animals,  and 
if  the  disposition  of  the  Vidian  nerve  at  its 
junction  with  the  facial  be  examined,  in  the 
horse  e.g.,  no  doubt  will  remain  that,  1.  the 
Vidian  nerve  certainly  does  not  run  simply  in 
apposition  with  the  facial  nerve,  and,  2.  the 
chorda  tympani  is  certainly  not  a  mere  conti- 
nuation of  the  Vidian  nerve.  In  the  horse  the 
facial  nerve  is  much  less  dense,  and  more  easily 
analyzed  than  in  man,  and  at  the  point  of  junc- 
tion with  the  Vidian  its  filaments  are  so  free 
and  so  loosely  connected,  that  little  more  is  re- 
quired than  to  open  the  packet  without  violence 
in  order  to  display  satisfactorily  the  disposition 
of  the  Vidian  at  its  junction  with  the  facial :  the 

*  Animal  (Economy,  p.  267. 

t  Journ.  Compl.  t.  xxiv.  p.  339,  341. 

i  Anatomie  Descriptive. 


FIFTH  PAIR  OF  NERVES. 


297 


Vidian  passes  into  the  interior  of  the  packet, 
crossing  its  fasciculi  nearly  at  right  angles,  but 
rather  in  a  reflex  direction,  and  then  spreads  out 
and  breaks  up  into  a  number  of  very  delicate  fila- 
ments with  which  cineritious  matter  is  inter- 
mixed, and  thus  a  ganglionic  structure  is  pro- 
duced, which  is  in  some  instances  more  mani- 
fest than  in  others,  and  is  at  the  same  time 
connected  with  fasciculi  of  the  facial  nerve. 
The  filaments  into  which  the  Vidian  separates 
can  be  followed  in  both  directions,  some  re- 
trograde, and  some  along  with  the  facial : 
the  former  appear  to  pass  partly  to  the  auditory 
nerve,  as  stated  by  Arnold,  and  partly  to  the 
facial  between  the  point  at  which  the  Vidian 
joins  it  and  the  brain  :  they  can  be  rent  from 
the  one  into  the  other,  and  indeed  look  more 
like  filaments  from  the  facial  to  the  Vidian  than 
from  the  latter  to  the  former.  The  latter  fila- 
ments of  the  Vidian  are  dispersed  among  the 
fasciculi  of  the  facial,  with  which  they  become 
united,  and  can  be  followed  by  means  of  a 
careful  dissection  for  some  distance :  their 
number  the  writer  is  not  prepared  to  state  :  the 
fasciculus  of  the  facial  from  which  the  chorda 
tympani  more  particularly  arises,  appears  deci- 
dedly to  receive  one  or  it  may  be  more.  Fur- 
ther, the  chorda  tympani  does  not  arise  by  a 
single  root,  but  is  formed  by  two  or  tliree  de- 
rived from  different  parts  of  the  facial.  The 
opinion  that  the  chorda  tympani  is  a  continu- 
ation of  the  Vidian  nerve  appears,  therefore,  to 
the  writer  altogether  unfounded,  and  while  he 
admits  that  the  conclusion  of  Arnold  may  proba- 
bly be  well-founded,  with  regard  to  its  compound 
nature,  he  yet  must  dissent  from  the  opinion  that 
the  branch  which  forms  it  arises  immediately 
from  the  gangliform  swelling  of  the  facial :  the 
fasciculus,  from  which  its  principal  root  pro- 
ceeds, existing  distinctly  upon  both  sides  of, 
and  consequently  not  arising  from  the  swelling, 
however  it  may  receive  an  accession  from,  or  be 
affected  by  its  connection  with  this  part.  The 
author  cannot  refrain  from  regarding  the  chord 
as  a  branch  of  the  facial  nerve  in  the  same  sense 
with  any  other  branch  arising  within  the  limits 
of  the  influence  of  the  Vidian  nerve.  Magendie 
maintains  that  the  chord  is  a  continuation  of 
the  Vidian,  because  the  section  of  the  fifth  nerve 
itself  deprives  the  ear  of  all  sensibility,  but 
whatever  part  the  chord  may  play  in  the  sensi- 
bility of  the  ear,  and  it  is  doubtful  that  it  plays 
any,  the  result  of  the  experiment  will  be  easily 
explained  by  the  doctrine  of  Eschricht,  that 
the  facial  nerve  owes  its  sensibility  to  the  fifth 
nerve,  the  division  of  which  must  in  such  case 
influence  through  the  Vidian  nerve  any  branch 
of  the  facial  arising  within  the  range  of  its  in- 
fluence. 

After  the  junction  of  the  chorda  tympani 
with  the  lingual  branch,  the  latter  gives  at  times 
a  small  branch  to  the  internal  pterygoid  mus- 
cle :  during  its  descent  along  the  ramus  of  the 
jaw,  it  also  gives  filaments  to  the  arches  of  the 
palate,  to  the  mucous  membrane  of  the  cheek, 
and  to  the  gum  of  the  lower  jaw.  While  the 
nerve  is  situate  between  the  mucous  membrane 
of  the  mouth  and  the  submaxillary  gland,  it  is 
connected  by  means  of  two,  three,  or  four  fila- 


ments with  the  submaxillary  ganglion.  This 
ganglion  is  a  small  reddish  body  resembling  the 
spheno-palatine  ganglion  in  size,  colour,  and 
consistence,  situate  above  the  posterior  extre- 
mity of  the  submaxillary  gland,  and  connected 
superiorly  with  the  lingual  branch  by  the  fila- 
ments mentioned  ;  inferiorly  there  arises  from 
it  a  considerable  number  of  very  delicate  nerves, 
which  descend  through  the  divisions  of  the 
gland,  anastomose  with  each  other,  and  are 
distributed  for  the  most  part  to  the  substance 
of  the  gland ;  one  of  them  descends  upon  the 
hyoglossus,  anastomoses  with  a  filament  from 
the  ninth,  and  enters  into  the  genioglossus 
muscle,  and  another  long  one  accompanies  the 
duct  of  the  gland.  A  filament  of  communi- 
cation also  from  the  superior  cervical  ganglion 
of  the  sympathetic  reaches  the  submaxillary 
ganglion  by  following  the  course  of  the  facial 
artery,  and  is  represented  by  Arnold. 

The  filaments  by  which  the  ganglion  is  con- 
nected to  the  lingual  branch,  are,  as  has  been 
stated,  two,  three,  or  four ;  they  are  not  attached 
to  the  nerve  all  together,  but  one  or  two  some 
lines  before  the  others,  and  they  are  remarkable 
for  the  circumstance,  that  the  posterior  descend 
forward,  while  the  anterior  descend  backward  ; 
on  attentive  examination  it  is  found  that  the 
posterior  are  derived  one  from  the  chorda  tym- 
pani, and  the  other  from  the  lingual  branch 
itself ;  it  also  appears  that  the  filament  derived 
from  the  former  source  is  but  a  part  of  the  cord, 
the  remainder  being  continued  on  with  the 
trunk  of  the  lingual,  and  again  that  the  anterior 
filament  or  filaments,  which  descend  backward 
to  the  ganglion,  are  continuations  of  the  poste- 
rior, which,  after  having  been  connected  to  the 
ganglion,  ascend  forward  from  it  again  to  the 
trunk  of  the  nerve.  The  course  of  those  fila- 
ments of  connection  is  well  described  and  re- 
presented by  the  elder  Meckel,  and  a  very  accu- 
rate delineation  of  them  is  given  by  Treviranus 
and  Arnold.  To  this  connection  probably  it 
is,  that  we  are  to  attribute  the  influence  which 
impressions  on  the  organs  of  taste,  or  even 
sounds  exert  upon  the  salivary  apparatus ;  let 
us,  when  hungry,  only  hear  a  sound  associated 
in  our  minds,  in  any  way,  with  the  gratification 
of  our  appetite,  and  at  once  that  apparatus  is 
roused  into  activity. 

Next,  while  lying  between  the  mylohyoid  and 
the  hyoglossus  muscles,  the  lingual  nerve  sends 
off  from  its  inferior  side  some  branches,  which 
descend  upon  the  hyoglossus,  and  anastomose 
with  filaments  ascending  from  the  ninth  nerve. 
At  the  same  time,  from  its  superior  side,  it 
gives  filaments  ;  some  of  which,  the  posterior, 
are  distributed  to  the  mucous  membrane  and 
to  the  gum  of  the  lower  jaw  ;  others,  the  ante- 
rior, to  the  sublingual  gland,  and  by  some  of 
their  ramifications  to  the  membrane  and  the 
gum.  Lastly,  the  nerve  divides  at  the  anterior 
margin  of  the  hyoglossus  into  its  lingual 
branches ;  these  are,  at  first,  three,  poste- 
rior, middle,  and  anterior ;  they  pass  up- 
ward and  forward,  and  divide,  each  into 
two  or  three  branches,  which  altogether  di- 
verge from  the  nerve,  and  are  ranged  in  suc- 
cession from  behind  forward,  along  the  line 


298 


FIFTH  PAIR  OF  NERVES. 


of  separation  between  the  stylo-glossus  and  the 

genio-glossus ;  they  traverse  the  substance  of 
the  tongue  toward  its  superior  surface  and  mar- 
gin, and  run  along  its  inferior  surface,  above 
the  mucous  membrane,  toward  its  extremity ; 
as  they  proceed  they  subdivide,  and  thus  re- 
sults a  great  number  of  filaments,  the  course 
of  which  through  the  tongue  is  remarkable ; 
they  appear  not  to  terminate,  any  of  them,  in 
the  substance  of  it,  but  they  traverse  it  as  long, 
slender,  single  filaments,  unconnected  with  its 
structure  until  they  approach  its  superior  sur- 
face, when  they  break  up  into  pencils  (to 
adopt  the  phrase  used)  of  still  more  delicate 
filaments,  which  may  be  followed  into  the  mu- 
cous membrane ;  the  posterior  filaments  of  the 
posterior  branch  insinuate  themselves  internal 
to  the  hyoglossus,  and  reach  as  far  back  as  the 
foramen  coecum ;  the  filaments  of  the  anterior 
are  distributed  to  the  extremity  of  the  tongue, 
and  are  continued  between  the  under  surface 
of  it  and  the  mucous  membrane  very  near  to 
the  tip,  the  substance  of  which  they  then  tra- 
verse in  order  to  reach  its  superior  aspect  and 
margin  :  they  thus  supply  the  mucous  mem- 
brane of  the  organ  upon  its  superior  and  lateral 
parts,  from  the  foramen  ccecum  to  its  point. 

Ganglion  of  the  fijtk  nerve  (Ganglion 
semilunare  Gasseri).  See  Jig.  140,  9.  —  The 
ganglion  of  the  fifth  nerve  is  a  body  of  crescentic 
form,  a  cineritious  colour,  and  firm  consistence. 
It  presents  two  surfaces,  two  margins,  and  two 
extremities :  its  surfaces  are  both  slightly  pro- 
minent, and  are  directed  one  upward,  outward, 
and  forward,  the  other  downward,  inward, 
and  backward ;  they  are  also,  the  former  con- 
cave and  the  latter  convex  longitudinally,  the 
ganglion  being  somewhat  curved  upon  itself  in 
the  same  direction  :  they  are  both  for  the  most 
part  adherent  to  the  lamina?  of  dura  mater, 
which  form  the  chamber  in  which  the  gan- 
glion is  contained ;  but  it  is  not  uncommon 
to  find  the  arachnoid  membrane  prolonged 
beneath  it,  so  that  its  inferior  surface  in  such 
instances  is  free ;  the  superior  corresponds  to 
the  cranial  cavity  in  its  middle  fossa,  being 
excluded  from  it  only  by  the  dura  mater;  the 
inferior  rests,  with  the  intervention  of  dura 
mater  also,  upon  the  petrous  portion  of  the 
temporal  bone,  the  great  ala  of  the  sphenoid, 
and  against  the  outer  side  of  the  cavernous 
sinus.  The  margins  of  the  ganglion  are  di- 
rected one  forward  and  downward,  the  other 
backward  and  upward  ;  the  anterior  is  convex, 
and  to  it  are  attached  the  three  great  trunks, 
which  compose  the  ganglionic  portion  of  the 
nerve  in  its  third  stage ;  the  posterior  is  con- 
cave and  presents  through  its  entire  length  a 
deep  groove,  into  which  the  fasciculi  of  the 
ganglionic  packet  of  the  nerve  are  received. 
The  extremities  are  obtuse,  and  project  beyond 
the  packet  at  either  side ;  they  are  situate  re- 
latively, one  superior,  internal,  and  anterior  to 
the  other.  When  the  ganglion  is  in  situ,  the 
chord  of  the  arch  which  it  forms  is  six  or 
seven  lines  long ;  Niemeyer  has  sometimes 
found  it  amount  to  from  nine  to  ten:*  its  width 

*  De  origine  pans  quinti  nervorum  cerebri  mono- 
graphia,  Halae,  1812. 


is  about  two  lines,  and  its  thickness,  according 
to  the  part,  from  half  a  line  to  a  line.  Its 
colour  and  appearance  vary  much  according 
to  the  subject :  the  former  is  always  of  a  cine- 
ritious tint  of  different  degrees  of  intensity  ; 
when  the  subject  is  wasted,  flabby,  or  anasar- 
cous,  it  is  pale  or  grey,  while,  if  the  subject 
have  been  robust  and  corpulent,  it  is  of  a  deep 
brown  colour :  in  the  former  case  also  a  plexi- 
form  arrangement  is  more  perceptible,  whereas 
in  the  latter  the  ganglion  seems  composed  of 
two  concentric  arcs,  an  anterior  of  lighter 
colour  and  manifestly  plexiform  character,  and 
a  posterior  of  very  deep  colour  and  apparently 
homogeneous  indeterminate  texture,  devoid  al- 
together of  the  plexiform  appearance. 

A  particular  inquiry  into  the  structure  and 
probable  function  of  the  ganglion  of  the  fifth 
nerve  would  involve  that  of  the  cerebro-spinal 
ganglia  in  general,  and  will  be  better  post- 
poned to  another  occasion  :  it  will  suffice  for 
the  present  to  state  that  according  to  both 
Monro  and  Scarpa,  they  are  composed  in 
part  of  nervous  chords,  and  in  part  by  a 
soft  grey  or  brown  substance,  which  fills 
the  intervals  between  the  nervous  filaments, 
and  which  according  to  the  former  resembles 
the  cortical  matter  of  the  brain,  while  in  the 
opinion  of  the  latter  it  is  a  cellular  texture 
filled  by  a  matter,  which  varies  in  character 
according  to  the  subject;  thus  he  states  that  he 
has  found  it  fatty  in  fat  and  watery  in  anasar- 
cous  subjects.  2.  That  nervous  filaments  can 
be  traced  through  them  without  interruption 
from  the  nerves  situate  above  to  those  situate 
below  the  ganglion,  which  opinion  is  objected 
to  by  Niemeyer,  who  compares  the  connection 
of  the  former  with  the  ganglion  to  that  of  the 
foetal  and  maternal  portions  of  the  placenta ; 
but  inspection  suffices  to  satisfy  one  that  this 
idea  of  Niemeyer  is  incorrect;  for  whether 
additional  filaments  be  furnished  or  not  by  the 
ganglion,  the  continuity  of  filaments  above 
and  below  it  is  evident  even  in  the  human 
subject,  and  is  still  more  manifest  in  other 
animals :  in  the  horse  it  is  easily  seen,  par- 
ticularly after  a  section  of  the  ganglion. 

The  question  whether  the  ganglion  receives 
filaments  from  the  sympathetic  system  has 
been  a  subject  of  dispute  among  anatomists. 
The  elder  Meckel*  denies  the  existence  of  any 
filaments  of  connection  between  the  sympa- 
thetic and  the  fifth  nerve,  while  within  the 
fibrous  chamber  or  while  situate  by  the  cavern- 
ous sinus ;  and  others  also,  among  whom  are 
Eustachius,  Haller,  Albinus,  and  Morgagni, 
are  of  the  same  opinion  ;  but  later  investiga- 
tions have  put  it  beyond  doubt  that  such  a 
communication  does  exist.  Bockf  has  de- 
scribed filaments  of  the  sympathetic  united  to 
the  trunk  of  the  fifth,  before  the  formation  of 
the  Gasserian  ganglion,  and  which  join  chiefly 
the  fasciculi  of  the  trunk,  from  which  the 
ophthalmic  nerve  originates.     And  Arnold 

*  Scriptores  Neurologici  Minores,  torn.  i. 

t  Beschreibung  des  funften  Nervenpaares  und 
seiner  Verbindung  mit  andern  Nerven,  vorzuglich 
mlt  dem  Gangliensystem,  1817. 


FIFTH  PAIR  OF  NERVES. 


299 


states  M  that  several  very  delicate  filaments  go 
from  the  carotid  plexus  to  the  semilunar  gan- 
glion, particularly  to  the  first  and  third  branches 
of  the  nerve,  and  upon  those  points  the  gan- 
glionic matter  is  accumulated  in  greater  abun- 
dance."* Besides  this  connection  between  the 
sympathetic  and  the  ganglion,  others  exist 
between  it  and  the  branches  of  the  ganglion. 

The  ganglion  appears  to  constitute  an  essen- 
tial part  of  the  fifth  nerve  throughout  verte- 
brate animals,  and  to  be  uniformly  present. 
It  also  presents  in  all  the  common  character 
of  being  composed  both  of  white  and  cineri- 
tious  matter,  though  the  comparative  amount 
of  the  two  constituents  vanes  according  to 
the  class,  the  order,  or  even  the  individual. 
The  presence  of  the  two  structures  the  author 
would  regard  as  essential  to  the  constitution 
of  cerebro-spinal  ganglia,  and  he  would  ex- 
clude from  such  those  enlargements  presented 
by  nerves  in  certain  situations,  but  from  which 
cineritious  matter  appears  to  be  absent.  In 
Mammalia,  Birds,  and  Reptiles,  the  fifth  nerve 
is  provided  with  a  single  ganglion,  but  in  Fish 
and  in  both  orders  of  that  class  it  possesses 
for  the  mosi  part  two  ganglia  and  two  gan- 
glionic fasciculi ;  this  however  is  not  uniformly 
so,  for  in  some,  e.  g.  the  lophius  piscatorius, 
the  ganglion  is  single. 

Vital  Properties  of  the  Fifth  Pair 
of  Nerves.  —  The  discussion  of  the  vital 
properties  of  the  fifth  nerve  the  writer  pro- 
poses may  be  fitly  arranged  under  the  following 
heads:  1.  its  sensibility;  2.  its  influence  upon 
the  faculties  of  sensation  and  volition,  as  also 
upon  the  ordinary  sensibility  of  the  parts  to 
which  it  is  distributed;  3.  its  relation  to  the 
special  senses  and  connection  with  the  function 
of  nutrition. 

1.  Sensibility. — Numerous  experiments  per- 
formed and  repeated  by  different  physiologists 
have  established  the  fact,  that  the  filth  nerve 
enjoys  exquisite  sensibility.  Bell  appears  to 
have  been  the  first  who  directed  attention 
particularly  to  this  point:  in  his  paper,  pub- 
lished in  the  Philosophical  Transactions  for  the 
year  1821,  it  is  stated  that,  touching  the  su- 
perior maxillary  branch  of  the  fifth  nerve, 
when  exposed  in  an  ass,  "  gave  acute  pain." 
In  the  first  of  Mayo's  experiments  upon  the 
fifth  nerve,  published  in  his  Commentaries 
in  1822,  it  was  also  found  that  "  on  pinching 
the  opposite  extremities"  (those  connected  with 
the  brain)  "  of  the  infraorbital  and  inferior 
maxillary  nerves  in  an  ass,  the  animal  struggled 
violently  as  at  the  moment  of  dividing  the 
nerves:  these  latter  results  uniformly  attend 
the  division  of  the  nerves  above-mentioned,  and 
of  that  branch  of  the  fifth  which  joins  the 
portio  dura."!  Similar  results  were  obtained 
by  the  writer  last  quoted  from  experiments 
of  the  same  description  upon  the  dog  and  the 
rabbit,  and  upon  the  pigeon,  in  regard  to  the 
first  division  of  the  fifth.  He  also  found 
"  that  on  pinching  the  gustatory  nerves  in 
living  rabbits  pain  was  evinced."  Magendie 

*  Journ.  Compl.  torn.  xxiv. 

t  Commentaries,  No.  1,  p.  110. 


carried  the  inquiry  farther,  and  in  the  fourth 
volume*  of  the  Journal  of  Physiology,  has 
related  an  experiment  in  which  he  exposed 
the  fifth  nerve  within  the  cranium  in  the  rabbit 
and  dog,  and  found  that  the  slightest  touch 
produced  signs  of  acute  sensibility.  From 
the  preceding  facts  we  infer  that  the  ganglionic 
portion  of  the  nerve  at  least  is  exquisitely 
sensitive,  and  that  it  is  endowed  with  sen- 
sibility through  its  entire  extent :  further,  the 
experiment  of  Magendie  indicates  that  the  sen- 
sibility of  the  nerve  is  proper  and  independent 
of  the  influence  of  other  nerves,  he  having  ex- 
perimented upon  it  at  a  point  prior  to  its 
junction  with  any  other. 

With  regard  to  the  non-ganglionic  portion 
of  the  nerve,  our  data  are  at  present  altogether 
analogical :  it  is  so  situated  that  satisfactory 
experiments  upon  it  separately  are  hardly  to 
be  accomplished,  so  that  we  are  left  to  infer 
of  it  as  probable  what  has  been  ascertained 
of  other  non-ganglionic  nervous  cords,  viz.  the 
anterior  roots  of  the  spinal  nerves.  The 
question  in  regard  to  the  functions  of  the 
different  portions  of  the  spinal  nerves  has  been 
inquired  into  by  Magendie,  by  whom  the 
endowments  of  both  sets  of  roots  have  been 
tested  in  various  modes,  and  who  has  inferred 
that  the  anterior  roots  are  not  devoid  of  sen- 
sibility, and  if  they  be  sensitive  it  is  probable 
that  the  lesser  packet  of  the  fifth  is  sensitive 
also.f 

2.  Influence  of  the  fifth  nerve  upon  sensation 
and  volition. —  It  is  hardly  necessary  to  remark 
that  this  point  has  been  the  subject  of  much 
dispute,  as  well  with  regard  to  the  fact  itself 
as  to  the  relative  claims  of  the  several  inquirers 
to  whom  we  are  indebted  for  the  investigation 
of  the  matter:  however,  physiologists  now 
seem  to  be  generally  agreed  that  the  nerve 
is  one  of  compound  function,  being  subservient 
to  both  the  faculties  of  sensation  and  volition, 
and  that  the  faculty  of  sensation  is  dependent 
upon  its  ganglionic,  that  of  voluntary  motion 
upon  its  non-ganglionic  portion,  and  that  it 
thus  resembles  the  spinal  nerves.  That  the 
nerve  is  one  of  compound  function,  and  sub- 
servient to  the  two  faculties,  was  announced 
by  Bell  in  the  paper  already  alluded  to.  He 
there  distinguishes  the  nerves  into  two  classes  ; 
one  original  and  symmetrical,  the  other  super- 
added and  irregular.  To  the  former  class  he 
refers  the  spinal  nerves,  the  suboccipital,  and 
the  fifth  nerve,  and  assigns  to  them  the  fol- 
lowing characters,  namely,  they  hive  all  double 
origins  ;  they  have  all  ganglia  on  one  of  their 
roots  ;  they  go  out  laterally  to  certain  divisions 
of  the  body;  they  do  not  interfere  to  unite 
the  divisions  of  the  frame ;  thei/  are  all  mus- 
cular nerves,  ordering  the  voluntary  motions 
of  the  frame  ;  they  are  all  exquisitely  sensible, 
and  the  source  of  the  common  sensibility  of 
the  surfaces  of  the  body :  to  ii  he  refers  the 
nerves  of  the  spine,  the  suboccipital,  and  the 
fifth  nerve. I    It  has  been  already  stated  that 

*  P.  314. 

t  Journal  tie  Physiologie,  t.  ii.  p.  368. 

X  Philosophical  Transactions,  1821,  p.  404. 


300 


FIFTH  PAIR  OF  NERVES. 


he  had  ascertained  by  experiment  that  the  fifth 
nerve  was  exquisitely  sensitive ;  that  it  is  the 
source  of  the  sensibility  of  the  parts  to  which 
it  is  distributed,  he  has  also  determined,  for 
in  allusion  to  the  fifth  he  says,  "  if  the  nerve 
of  this  original  class  be  divided,  the  skin  and 
common  substance  is  deprived  of  sensibility;"* 
and  "  by  an  experiment  made  on  the  16th 
of  March,  it  was  found  that,  on  cutting  the 
infra-orbitary  branch  of  the  fifth  on  the  left 
side,  the  sensibility  of  that  side  was  completely 
destroyed/' f  The  experiments  of  Bell  were 
repeated  by  Magendie,  and  a  similar  result, 
so  far  as  regards  the  sentient  properties  of  the 
fifth,  obtained,  as  mentioned  in  the  Journal 
de  Physiologie,  Octobre  1821.  A  similar 
result  has  been  obtained  also  by  Mayo  in  his 
experiments  upon  the  fifth  nerve,  as  detailed 
in  his  Commentaries  for  August  1822,  more 
than  a  year  after  the  publication  of  Bell's 
paper.  In  his  first  experiment  the  infra-orbital 
and  inferior  maxillary  branches  were  divided 
on  either  side  in  an  ass,  where  they  emerge 
from  their  canals,  and  the  sensibility  of  the 
lips  seemed  to  be  destroyed  :  and,  in  a  second 
experiment,  the  frontal  nerve  was  divided  on 
one  side  of  the  forehead  of  an  ass,  when  the 
neighbouring  surface  appeared  to  lose  its  sen- 
sibility :  the  same  effect  was  produced  by  the 
division  of  that  branch  of  the  fifth  which  joins 
the  portio  dura,  inasmuch  as  the  cheek  loses 
sensation  upon  its  division.  From  these  ex- 
periments Mayo  concluded  that  the  facial 
branches  of  the  fifth  are  nerves  of  sensation. 
The  experiments  upon  the  influence  of  the 
nerve  on  sensation  have  been  carried  still 
further  by  Magendie ;  he  divided  the  nerves 
within  the  cranium,  where  they  lie  against 
the  cavernous  sinus,  and  also  between  the  pons 
Varolii  and  the  petrous  portion  of  the  temporal 
bone,  and  in  both  instances  he  obtained  the 
same  result  with  regard  to  the  sensibility  of 
the  parts  to  which  the  nerves  are  distributed, 
viz.  total  loss  of  sensibility  on  one  or  both 
sides  of  the  face,  according  as  one  or  both  nerves 
were  divided  ;  this  extended  not  only  to  the 
integuments  as  in  the  former  trials,  but  also 
to  the  lining  membrane  of  the  nostrils,  to  the 
conjunctiva,  to  the  tongue  and  the  interior 
of  the  mouth.  The  effect  upon  the  nostril  was 
so  remarkable  that  the  most  active  effluvia, 
even  those  of  ammonia  and  acetic  acid,  pro- 
duced no  impression  upon  it:  in  like  manner 
neither  piercing  instruments  nor  ammonia  ex- 
cited any  sensation  when  applied  to  the  con- 
junctiva, and  the  tongue  was  insensible  to  the 
action  of  sapid  bodies  at  its  anterior  part. 

From  such  accumulated  evidence  but  one 
conclusion  can  be  drawn,  viz.  that  the  fifth 
is  the  nerve  of  general  and  tactile  sensation 
to  the  face  and  its  cavities,  or  to  the  parts 
upon  which  it  is  distributed. 

With  regard  to  the  influence  of  the  fifth 
nerve  upon  volition,  it  has  been  already  stated 
that  Bell  had  announced  it,  as  one  of  his  regular 
or  symmetrical  nerves,  to  be  "  a  muscular 

*  Philosophical  Transactions,  1821,  p.  405. 
f  Ibid.  p.  417. 


nerve  ordering  the  voluntary  motions."  This 
conclusion  with  regard  to  the  fifth  nerve  he 
adopted  in  consequence  of  the  following  ex- 
periment, and  of  the  result,  which,  as  he 
conceived,  he  obtained  from  it.  "  An  ass  being 
tied  and  thrown,  the  superior  maxillary  branch 
of  the  fifth  nerve  was  exposed.  Touching 
this  nerve  gave  acute  pain.  It  was  divided, 
but  no  change  took  place  in  the  motion  of 
the  nostril ;  the  cartilages  continued  to  expand 
regularly  in  time  with  the  other  parts  which 
combine  in  the  act  of  respiration ;  but  the 
side  of  the  lip  was  observed  to  hang  low,  and 
it  was  dragged  to  the  other  side.  The  same 
branch  of  the  fifth  was  divided  on  the  opposite 
side,  and  the  animal  let  loose.  He  could  no 
longer  pick  up  his  corn ;  the  power  of  elevating 
and  projecting  the  lip,  as  in  gathering  food, 
was  lost.  To  open  the  lips  the  animal  pressed 
the  mouth  against  the  ground,  and  at  length 
licked  the  oats  from  the  ground  with  his  tongue. 
The  loss  of  motion  of  the  lips  in  eating  was 
so  obvious,  that  it  was  thought  a  useless  cruelty 
to  cut  the  other  branches  of  the  fifth."  The 
inference  here  indicated  is  obvious,  viz.  that 
the  motion  of  the  lips  in  eating  depends  upon 
the  superior  maxillary  branches  of  the  fifth 
pair,  so  far  at  least  as  the  distribution  of  those 
branches  extends ;  and  what  he  conceived  he 
had  thus  established  with  regard  to  one  branch 
he  inferred  analogically  of  the  rest.  The 
opinion  that  the  fifth  is  a  muscular  nerve  as 
well  as  one  of  sensibility  Bell  also  maintains 
in  later  writings,  and  supports  by  additional 
experiments  :  thus,  in  his  Erposition  of  the 
Natural  System  of  the  Nerves,  published  in 
1824,  he  says,  "  to  confirm  this  opinion  by 
experiment,  the  nerve  of  the  fifth  pair  was 
exposed  at  its  root,  in  an  ass,  the  moment 
the  animal  was  killed ;  and  on  irritating  the 
nerve  the  muscles  of  the  jaw  acted,  and  the 
jaw  was  closed  with  a  snap.  On  dividing  the 
root  of  the  nerve  in  a  living  animal,  the  jaw 
fell  relaxed."  That  the  fifth  is  to  a  certain 
extent  a  nerve  of  voluntary  motion  is  univer- 
sally admitted,  but  then  a  question  arises  of 
equal  interest  and  delicacy;  of  interest  for 
its  own  nature,  and  of  delicacy  because  of  the 
personal  claims  and  feelings  involved  in  it. 
The  question  is, — it  being  admitted  that  the 
nerve  is  one  of  double  function,  —  is  such 
function  enjoyed  equally  by  all  its  branches 
and  by  both  its  portions  ;  and  if  otherwise, 
upon  which  do  they  severally  depend  ?  From 
the  extracts  quoted  it  is  evident  that  no  dis- 
tinction in  function  between  the  different 
branches  of  the  nerve  was  contemplated  by 
Bell  at  the  time  the  first  was  written,  in  1821, 
and  that  he  regarded  them  as  being  all  alike 
nerves  of  compound  function, — nerves  both 
of  voluntary  motion  and  sensation;  and,  such 
being  the  case,  either  that  he  had  not  recognised 
a  difference  between  the  properties  of  the  gan- 
glionic and  the  non-ganglionic  portions  of  the 
nerve,  or  that  he  was  then  not  aware  of  the 
peculiar  distribution  of  the  latter ;  nor  is  any 
express  information  afforded  us  upon  the  subject 
in  his  earlier  writings,  or  antecedent  to  1823. 
The  conclusion  to  which  he  had  arrived  with 


FIFTH  PAIR  OF  NERVES. 


301 


regard  to  the  nerve  generally  and  its  superior 
maxillary  branch  in  particular,   in  the  year 
1821,  has  been  stated  ;  in  his  communication 
to  the  Royal  Society  in  1823,  he  adds,  "  all 
the  nerves,  without  a  single  exception,  which 
bestow  sensibility  from  the  top  of  the  head 
to  the  toe  have  ganglia  on  their  roots ;  and 
those  which  have  no  ganglia  are  not  nerves 
of  sensation,  but  are  for  the  purpose  of  or- 
dering the  muscular  frame:"  from  this,  when 
applied  to  the  fifth  nerve,  it  might  be  inferred 
that  sensation  depended  upon  its  ganglionic, 
and  muscular  action  upon  its  non-ganglionic 
portion.     But  between  the  years  1821  and 
1823  additions  had  been  made  by  others  to 
the  knowledge  of  the  functions  of  the  fifth 
nerve  which  require  notice.    It  is  to  be  borne 
in  mind  that  Bell  inferred  from  his  first  ex- 
periment, published  in  1821,  that  the  superior 
maxillary  nerve  is  one  both  of  sensation  and 
voluntary  motion  to  the  lips  (see  the  preceding 
page) :  to  this  conclusion  Magendie  was  the  first 
to  object,  for  in  the  Journal  of  Physiology  for 
October  of  the  same  year  (1821),  he  says, 
"  we  have  repeated  these  experiments  along 
with  Messrs.  Shaw  and  Dupuy,  and  the  result 
which  we  have  obtained  agrees  perfectly  with 
that  which  we  have  just  related,  with  the  ex- 
ception always  of  the  influence  of  the  section 
of  the  infra-orbital  upon  mastication,  an  in- 
fluence which  I  have  never  been  able  to  perceive." 
In  August  1822  Mayo  published,  in  his  Com- 
mentaries, his  "  experiments  to  determine  the 
influence  of  the  portio  dura  of  the  seventh, 
and  of  the  facial  branches  of  the  fifth  pair 
of  nerves."    Those  relating  to  the  latter  point, 
which  have  been  already  alluded  to,  are  as 
follow.    1.  The  infra-orbital  and  inferior  max- 
illary branches  of  the  fifth  were  divided  on 
either  side,  where  they  emerge  from  their  re- 
spective canals;    the  lips  did  not  lose  their 
tone  or  customary  apposition  to  each  other 
and  to  the  teeth  ;  but  their  sensibility  seemed 
destroyed  :    when   oats   were  offered  it,  the 
animal  pressed  its  lips  against  the  vessel  which 
contained  the  food,  and  finally  raised  the  latter 
with  its  tongue  and  teeth.    On  pinching  with 
a  forceps  the  extremities  nearest  the  lips  of 
the  divided  nerves,   no  movement  whatever 
of  the  lips  ensued  :  on  pinching  the  opposite 
extremities  of  the  nerves,  the  animal  struggled 
violently,  as  at  the  moment  of  dividing  the 
nerves.     Some  days  afterwards,  though  the 
animal  did  not  raise  its  food  with  its  lips, 
the  latter  seemed  to  be  moved  during  mastica- 
tion by  their  own  muscles." 

2.  "  Some  days  after,  the  frontal  nerve  was 
divided  on  one  side  of  the  forehead  of  the 
same  ass,  when  the  neighbouring  surface 
appeared  to  have  lost  sensation,  but  its  muscles 
were  not  paralysed."  4,  5,  and  6.  The  branch 
of  the  fifth,  that  joins  the  portio  dura,  was 
divided  on  either  side  :  in  the  fourth  experi- 
ment, the  under  lip  at  first  appeared  to  fall 
away  from  the  teeth;  at  times  the  lips  were 
just  closed:  in  the  fifth  and  sixth,  the  under 
lip  did  not  hang  down,  and  no  difference  was 
observed  between  the  action  of  the  muscles  of 
either  side ;  but,  he  observes  in  a  later  publi- 


cation, "  the  cheek  loses  sensation  upon  its 
division."    The  results  of  these  experiments, 
while  they  confirm  fully  the  inference  drawn 
by  Bell  with  regard  to  the  influence  of  the 
nerve  over  sensation,  are  altogether  at  variance 
with  that  of  his  experiment  relating  to  the  con- 
trol of  the  superior  maxillary  nerve  over  mus- 
cular motion,  and  are  equally  incompatible 
with  the  doctrine  that  the  branches  of  the  nerve., 
which  were  the  subjects  of  experiment,  have 
any  direct  connexion  with  muscular  contrac- 
tion ;  for  while,  on  the  one  hand,  the  division 
of  the  nerves  was  followed  by  total  loss  of 
sensibility  in  the  lips,  on  the  other,  the  latter 
did  not  fall  away  either  from  each  other  or 
from  the  teeth,  nor  did  irritation  of  the  portions 
of  the  nerves  connected  with  the  lips  excite 
any  movement  whatever  of  those  parts,  but 
they  seemed  afterwards  to  be  moved  during 
mastication  by  their  own  muscles.    Mayo  in- 
ferred accordingly  from  his  experiments,  "  that 
the  frontal,  infra-orbital,  and  inferior  maxillary 
are  nerves  of  sensation  only,  to  which  office 
that  branch  of  the  fifth  which  joins  the  portio 
dura  probably  contributes."    A  circumstance 
in  the  first  experiment  doubtless   seems  at 
variance  with  the  conclusion  which  Mayo  has 
drawn,  and  demands  consideration  here,  be- 
cause, unless  unexplained,  the  fact  is  inconsis- 
tent with  the  inference.    It  has  been  stated 
that  both  in  Bell's  and  Mayo's  experiment,  the 
animal  ceased  to  take  up  its  food  with  its  lips 
after  the  division  of  the  facial  branches  of  the 
fifth,  and  from  that  circumstance  chiefly  the 
former  appears  to  have  inferred  that  the  motions 
of  the  lips  in  eating  depended  on  these  nerves  ; 
but  the  inference  is  objected  to  by  Mayo  as 
"  a  theoretical  account  of  the  fact  that  the 
animal  did  not  elevate  and  project  its  lip  ;  this 
fact,"  he  says,  "  was  noticed  in  my  own  expe- 
riments, but  appeared  to  me  from  the  first 
equally  consistent  with  the  hypothesis,  that  the 
lip  had  merely  lost  its  sensibility,  as  with  Mr. 
Bell's  explanation,"  that  it  had  lost  its  muscu- 
lar power.     The  fact  may  be  obviously  ex- 
plained by  either  of  the  two  suppositions,  and 
it  is  very  remarkable  that   it  should  occur 
equally  in  one  case  as  in  the  other.    In  the 
one,  the  muscles  of  the  lips  having  been  de- 
prived of  their  power  of  voluntary  contraction, 
the  lips  themselves  cannot,  of  course,  be  made 
use  of  to  take  hold  of  an  object ;  and  in  the 
other,  the  animal  not  being  made  aware  of  the 
contact  of  the  food  in  consequence  of  the  loss 
of  sensation,  volition  is  not  exerted,  nor  are 
the  muscles  called  into  action  in  order  to  take 
hold  of  it.    To  the  latter  cause  it  is  attributed 
by  Mayo,  after  the  division  of  the  branches  of 
the  fifth,  and  he  confirms  this  view  of  its  pro- 
duction by  reference  to  the  effect  of  anaesthesia 
in  the  human  subject :   "  in  that  disease  the 
sensation  of  the  extremities  is  wholly  lost, 
while  their  muscular  power  remains.    Now  it 
is  remarkable  that  in  persons  thus  affected  the 
muscles  of  the  insensible  part  can  only  be 
exerted  efficiently  when  another  sense  is  em- 
ployed to  guide  them,  and  to  supply  the  place 
of  that  which  has  been  lost :  a  person  afflicted 
with  anaesthesia  is  described  in  a  case  quoted 


302 


FIFTH  PAIR  OF  NERVES. 


by  Dr.  Yelloly,  as  liable  on  turning  her  eyes 
aside  to  drop  glasses,  plates,  &c.  which  she 
held  in  safety  so  long  as  she  looked  at  them  ;" 
but  that  the  absence  of  motion  in  the  lips  on 
the  division  of  the  fifth  is  due  to  the  loss  of 
sensation  merely,  and  not  of  voluntary  power, 
is  positively  proved  by  the  effect  of  the  division 
of  the  portio  dura  on  the  two  sides,  an  experi- 
ment performed  for  the  first  time  by  Mayo  :  in 
it  the  voluntary  motion  of  the  lips  is  altogether 
lost,  while  sensation  continues  unaffected,*  and 
hence  the  division  of  the  fifth  cannot  deprive 
them  of  voluntary  power,  but  only  of  sensation. 
The  explanation  of  Mayo  has  been  admitted 
and  adopted  by  Bell  himself  in  his  "  Exposi- 
tion," 1824,  in  which  he  has  added  to  the 
detail  of  his  experiment,  as  already  related, 
the  following  note  :  "  what  I  attributed  to  the 
effect  of  the  loss  of  motion  by  the  division  of 
the  fifth,  was  in  fact  produced  by  loss  of  sen- 
sation;" and  he  corroborates  this  by  the  case 
of  a  gentleman  in  whom  loss  of  sensation  in 
the  lip  had  been  produced  by  extraction  of  a 
tooth.  "  On  putting  a  tumbler  of  water  to  his 
lips,  he  said,  '  Why,  you  have  given  me  a 
broken  glass  :'  he  thought  that  he  put  half  a 
glass  to  his  lips,  because  the  lip  had  been  de- 
prived of  sensation  in  one  half  of  its  extent ; 
lie  retained  the  power  of  moving  the  lip,  but 
not  of  feeling  with  the  lip."  The  last  particu- 
lar noted  is  of  great  value,  as  demonstrating 
satisfactorily  the  separation  of  the  two  faculties, 
and,  taken  in  connexion  with  anatomical  con- 
siderations, renders  it  necessary  to  refer  them 
to  separate  sources.  It  is  manifest,  then,  that 
the  circumstance  of  the  animal  not  taking  up 
the  food  by  means  of  the  lips,  after  the  divi- 
sion of  the  fifth  nerve,  is  not  proof  that  it  had 
lost  the  voluntary  muscular  power  of  them, 
but  only  that  it  did  exert  it,  not  having  been, 
as  it  were,  apprised  of  the  necessity  of  doing 
so.  It  is  also  stated  by  Bell,  that  on  the 
division  of  the  nerve  upon  one  side,  "  the  side 
of  the  lip  was  observed  to  hang  low,  and  it 
was  dragged  to  the  other  side."  This  result 
also  is  objected  to  by  Mayo,  first,  as  contrary 
to  his  observation,  for  in  his  first  experiment, 
after  the  division  of  the  infra-orbital  and  inferior 
maxillary  nerves,  "  the  lips  did  not  lose  their 
tone  or  customary  apposition  to  each  other  and 
to  the  teeth;"  and  secondly,  as  being  the 
effect  of  an  extensive  division  of  the  muscular 
fibres,  a  cause  quite  adequate  certainly  to 
explain  the  fall  of  the  lip,  independent  of  the 
influence  of  the  nerves.  The  difficulty,  there- 
fore, which  these  circumstances  appear  at  first 
to  present  is  removed,  and  we  are  left  to  deter- 

*  It  will  be  satisfactory  to  those  interested  in 
this  question  to  know,  that  the  result  of  Mayo's 
experiment  has  received  full  confirmation  from 
those  of  others;  and  first  from  Shaw,  who  has 
bestowed  so  much  labour  to  establish  the  respiratory 
connexion  of  the  portio  dura.  In  the  Medical  and 
Physical  Journal  for  December,  1822,  he  writes, 
"  immediately  on  cutting  the  nerve  (the  portio 
dura)  on  both  sides,  the  lips  became  so  paralyzed 
that  the  animal  could  no  longer  use  them  in  raising 
its  food."  The  same  result  has  been  obtained  by 
Mr.  Broughton  in  experiments  upon  the  horse,  as 
detailed  in  the  same  Journal,  June,  1823. 


mine  the  question  by  other  means,  and  they 
are  abundantly  furnished  from  other  sources. 
In  the  first  place,  the  division  of  the  nerves 
completely  destroys  the  sensation  of  the  parts 
to  which  they  are  distributed,  without  pro- 
ducing any  effect  upon  the  tone  or  contractile 
power  of  those  parts,  nor  does  irritation  of  the 
divided  nerves  excite  muscular  contractions. 
Secondly,  were  these  nerves  the  source  of  the 
voluntary  powers  of  the  parts  they  supply,  the 
division  of  every  other  nerve  must  fail  to  affect 
that  power  while  the  former  remain  entire; 
but  Mayo,  in  several  instances,  divided  the 
portio  dura  alone  on  both  sides,  and  the 
result  was,  that  "  the  lips  immediately  fell 
away  from  the  teeth,  and  hung  flaccid,"  and 
could  not  be  used  by  the  animal  to  take  hold 
of  food,  and  consequently  had  lost  ail  volun- 
tary power ;  while,  "  when  the  extremity, 
nearest  the  lips,  of  either  divided  nerve  was 
pinched,  the  muscles  of  the  lips  and  nostrils 
on  that  side  were  convulsed."  Bell  doubtless 
asserts  that  after  the  division  of  the  portio  dura 
nerve  on  one  side,  the  animal  "  ate  without 
the  slightest  impediment;"  to  this  Mayo 
objects  that  "  the  experiment  is  inconclusive, 
because  the  nerve  was  not  divided  on  both 
sides;"  but  in  truth  the  experiment  is  quite 
conclusive,  for  though  the  animal  can  eat,  and 
without  impediment,  his  eating  is  far  from 
perfect,  and  the  imperfection  is  not  the  less 
obvious  because  confined  to  one  side. 

When  an  animal  which  has  had  the  portio 
dura  divided  upon  one  side  only  takes  food, 
the  lips  remain  motionless  upon  that  side;  and 
when  it  masticates,  the  lips  continue  in  the 
same  state,  while  on  the  otheT  side  they  ac- 
tively co-operate,  the  food  and  saliva  escaping 
on  the  side  at  which  the  nerve  has  been  cut, 
and  on  the  other  being  confined  within  the 
mouth.  Now,  if  any  action  of  the  lips  be 
voluntary,  it  is  assuredly  that  by  which  they 
co-operate  in  the  prehension  and  mastication 
of  food ;  and  since  no  action  of  their  muscles 
can  be  excited  by  irritation  of  the  branches  of 
the  fifth  nerve,  while  such  action  can  be  ex- 
cited by  that  of  the  portio  dura,  and  all  volun- 
tary action  is  destroyed  by  the  division  of  that 
nerve,  but  one  inference  remains,  that  ot  Mayo 
already  adverted  to,  viz. — that  those  branches 
of  the  fifth  in  question  possess  no  influence 
upon  the  voluntary  faculty  of  the  muscles ; 
that  they  are  exclusively  sentient ;  and  that  the 
contractile  power  of  the  muscles  of  the  face, 
whether  voluntary  or  involuntary,  is  to  be  attri- 
buted to  another  source. 

After  what  has  been  stated,  we  must  admit 
that  Mayo  has  been  the  first  expressly  to  an- 
nounce that  the  function  of  these  nerves  is 
restricted  to  sensation.  Beyond  that,  however, 
he  has  not  gone,  in  reference  to  the  question 
of  sensation,  in  the  publication  alluded  to, 
though  it  must  be  admitted  that  little  remained 
to  be  added  in  order  to  complete  the  conclu- 
sion, that  the  ganglionic  portion  of  the  nerve  is 
exclusively  sentient.  At  the  same  time  he 
inferred,  "  from  the  preceding  anatomical 
details," — viz.  their  exclusive  distribution  to 
muscles, — "  that  other  branches  of  the  third 


FIFTH  PAIR  OF  NERVES. 


303 


division  of  the  fifth  are  voluntary  nerves  to  the 
pterygoid,  the  masseter,  the  temporal,  and 
buccinator  muscles."  Here  again  he  has  not 
reached  the  conclusion,  though  he  has  fallen 
but  little  short  of  it,  and  though,  as  in  the 
former  instance  with  regard  to  sensation,  he 
has  been  the  first  to  announce  a  restriction  of 
the  motor  properties  of  the  nerve  to  particular 
branches.  The  opinion  expressed  by  Bell,  in 
June  1823,  has  been  already  quoted,  and 
from  it  we  are  bound  to  admit,  that  then  at  least 
he  recognised  the  distinction  at  present  acknow- 
ledged with  reference  to  the  appropriate  function 
of  the  ganglionic  and  non-ganglionic  portions. 
But  in  Mayo's  Commentaries  for  July  1823,  the 
conclusion  is  for  the  first  time  expressly  stated 
thus : — "  In  the  last  paper  of  the  preceding 
number,  I  mentioned  that  the  division  of  the 
supra-orbital,  infra-orbital,  and  inferior  max- 
illary nerves,  at  the  points  where  they  emerge 
from  their  canals  upon  the  face,  produces  loss 
of  sensation,  and  of  that  alone,  in  the  corres- 
ponding parts  or  the  face.  I  have  since,  after 
the  division  of  the  fourth  branch  which  emerges 
on  the  face, — namely,  that  which  joins  the 
portio  dura, — ascertained  that  this  branch  like- 
wise is  a  nerve  of  sensation,  inasmuch  as  the 
cheek  loses  sensation  upon  its  division.  I 
mentioned  in  addition  that  I  concluded  that 
other  branches  of  the  fifth  nerve,  from  their 
distribution,  are  voluntary  nerves.  Now  it  is 
well  known  that  the  fifth  nerve  at  its  origin 
consists  of  two  portions  ;  a  larger  part,  which 
alone  enters  the  Gasserian  ganglion,  and  ano- 
ther smaller,  which  does  not  enter,  but  passes 
below  the  ganglion  to  join  itself  with  the  third 
division  of  the  fifth.  Towards  the  close  of 
last  summer  I  endeavoured  to  trace  the  final 
distribution  of  this  small  portion  in  the  ass, 
and  succeeded  in  making  out  that  it  furnishes 
those  branches,  which  are.  distributed  exclu- 
sively to  muscles  :  I  have  since  ascertained 
that  in  the  human  body  precisely  the  same 
distribution  exists.  But  the  iemaining  branches 
of  the  fifth  are  proved  to  be  nerves  of  sensation  ; 
thus  it  appears  that  the  fifth  nerve  consists  of 
two  portions,  one  of  which  has  no  ganglion, 
and  is  a  nerve  of  voluntary  motion  (and  pro- 
bably of  muscular  sensation) ;  and  another, 
which  passes  through  a  ganglion,  and  furnishes 
branches,  which  are  exclusively  nerves  of  the 
special  senses." 

We  return  now  to  the  question  of  the  pro- 
perties of  the  non-ganglionic  portion  of  the 
fifth  nerve.  It  has  been  stated  that  Mayo  was 
the  first  to  announce  the  restriction  of  the 
voluntary  influence  of  the  fifth  to  certain 
branches,  and  that  he  was  led  to  this  conclu- 
sion from  the  observation  of  the  fact  that  certain 
branches  of  the  nerve  ate  distributed  exclusively 
to  muscles.  These  muscles  he  has  stated,  in 
the  first  part  of  his  Commentaries,  to  be  the 
pterygoid,  the  masseter,  the  temporal,  and 
buccinator;  to  which  he  has  added,  in  his 
second  part,  the  circumflexus  palati ;  by  dis- 
section he  ascertained  that  as  well  in  man  as 
in  the  ass,  the  lesser  portion  of  the  nerve  "  fur- 
nishes those  branches  which  are  distributed  ex- 
clusively to  muscles;"   and   having  already 


determined  that  the  ganglionic  portions  of  the 
nerve  are  destined  exclusively  to  sensation,  he 
came  to  the  conclusion  that  the  non-ganglionic 
portion  is  a  nerve  of  voluntary  motion.  His 
first  conclusion  upon  this  point  he  himself 
states  to  have  "  involved  a  trifling  error  :  the 
pterygoid,  masseter,  and  temporal  muscles  are 
indeed  exclusively  supplied  by  the  fifth,  and 
therefore,  without  doubt,  the  branches  so  dis- 
tributed are  voluntary  nerves,  but  the  bucci- 
nator receives  branches  from  the  portio  dura  as 
well,  and  I  have  found  subsequently,  that 
pinching  the  branch  of  the  fifth  that  perforates 
the  muscle,  produces  no  action  in  it :  and  in 
accordance  with  this  view  he  writes  in  his 
Physiology,*  "  I  was  led  to  observe  that  there 
were  muscles  which  received  no  branches  from 
any  nerve  but  the  fifth  ;  these  muscles  are  the 
masseter,  the  temporal,  the  two  pterygoids, 
and  the  circumflexus  palati.  After  some  care- 
ful dissection,  I  made  out  that  the  smaller 
fasciculus  of  the  fifth  is  entirely  consumed 
upon  the  supply  of  the  muscles  1  have  named." 
The  determination  of  the  constitution  and 
function  of  the  buccal  branch  of  the  inferior 
maxillary  nerve  has  become  a  matter  of  greater 
importance  since  the  publication  of  Bell's 
work  on  the  Nervous  System  in  1830.  In  it 
he  says,  "  I  am  particular  in  re-stating  this, 
because  from  time  to  time  it  has  been  reported 
that  I  had  abandoned  my  original  opinions, 
whereas  every  thing  has  tended  to  confirm 
them."  Now,  it  will  be  remembered  that 
Bell's  original  opinion  is,  that  the  muscles  of 
the  face  are  endowed  with  two  powers,  a  volun- 
tary one,  dependent  on  the  fifth  nerve,  and  an 
involuntary  respiratory  one,  dependent  on  the 
portio  dura ;  also,  that  in  the  first  instance  he 
attributed  the  voluntary  power  of  these  muscles 
to  the  facial  branches  of  the  fifth,  but  that  he 
had  abandoned  that  idea,  and  acknowledged 
that  what  he  had  attributed  to  loss  of  motion 
was  in  fact  due  to  loss  of  sensation.  In  the 
work  adverted  to  he  has  taken  new  ground, 
and  at  the  same  time  reiterates  his  first  opinion 
with  regard  to  the  existence  of  the  two  distinct 
contractile  powers  in  the  muscles  of  the  face, 
and  attributes  to  the  buccal  nerve  that  influence 
over  their  voluntary  motion  which  he  had 
before  referred  to  the  infra-orbital,  &c.  Thus, 
"  but  finding  that  the  connexion  between  the 
motor  root  and  the  superior  maxillary  nerve 
proved  to  be  only  by  cellular  texture,  and  con- 
sidering the  affirmation  of  M.  Magendie  and 
those  who  followed  him,  that  the  infra-orbitary 
branch  had  no  influence  upon  the  lips,  I  pro- 
secuted with  more  interest  the  ramus  buccinalis 
labialis," — the  buccal  nerve, — "  and  nobody, 
I  presume,  will  doubt  that  the  distribution  of 
this  division  confirms  the  notions  drawn  from 
the  anatomy  of  the  trunk,  not  only  that  the  fifth 
nerve  is  the  manducatory  nerve  as  it  belongs 
to  the  muscles  of  the  jaws,  but  also  that  it  is 
distributed  to  the  muscles  of  the  cheek  and 
lips  to  bring  them  into  correspondence  with 
the  motions  of  the  jaws."  To  the  point  at 
issue  the  writer  has  directed  particular  atten- 

*  1833,  p.  261. 


304 


FIFTH  PAIR  OF  NERVES. 


tion  :  he  has  made  repeated  dissections  of  the 
distribution  of  the  lesser  packet  of  the  nerve 
both  in  the  horse  and  in  man,  and  after  a  care- 
ful examination,  it  appears  to  him  that  Mayo 
is  essentially  right,  though  the  view  given  by 
him  does  not  exactly  agree  with  the  arrange- 
ment of  the  nerve  as  found  by  the  author 
either  in  the  horse  or  in  man.  In  the  former  the 
masseteric  branch  arises  from  the  lesser  packet 
by  two  fasciculi,  one  of  which  runs  round  the 
ganglionic  portion  of  the  third  division  of  the 
nerve,  and  joins  the  other  and  larger  fasciculus 
before  it :  the  facial  portion  of  the  buccal 
nerve  appears  to  the  author  to  be  purely  gan- 
glionic, but  the  root  of  the  nerve  in  part 
appears  to  be  derived  from  the  non-ganglionic 
portion  and  is  not ;  and  in  part  may  or  may 
not  be  considered  to  proceed  from  it.  It  is 
entangled  at  its  origin  with  fasciculi  of  that  por- 
tion, more  or  fewer  of  the  filaments  which  it 
derives  from  the  ganglionic  packet  passing  be- 
tween and  even  interlacing  with  fasciculi  of  the 
non-ganglionic ;  but  by  a  patient  proceeding 
these  may  be  traced  to  their  proper  source,  and 
the  nerve  be  extricated  from  this  connexion.  It 
is,  however,  difficult  to  accomplish  it  at  times, 
at  others  it  is  sufficiently  easy.  Again,  one  or 
more  branches  of  the  non-ganglionic  portion 
accompany  the  buccal  nerve  for  some  distance, 
connected  to  it  more  or  less  intimately,  but 
apparently  not  enclosed  within  the  same  sheath, 
though  communicating  with  the  nerve  by  fila- 
ments from  a  ganglionic  fasciculus  and  separa- 
ble without  injury  to  either.  These  branches, 
however,  separate  from  the  nerve  again  for  dis- 
tribution before  it  leaves  the  zygomatic  fossa ; 
they  may  be  considered,  or  not,  to  belong  to 
the  nerve,  but  they  do  not  affect  the  question 
with  regard  to  its  facial  portion  ;  and  the  author 
believes  that  the  arrangement  described  is  not 
uniform,  the  branches  adverted  to  not  always 
accompanying  the  buccal  nerve. 

Again,  on  the  one  hand  it  has  been  already 
shewn  that  division  of  the  portio  dura  on  both 
sides  deprives  the  facial  muscles  of  all  inde- 
pendent* contractile  power,  whether  voluntary 
or  involuntary  ;  and  on  the  other,  Mayo  has 
found  that  irritation  of  the  buccal  nerve  does 
not  excite  contraction  in  those  muscles  :  the 
author  has  taken  occasion  several  times  to 
repeat  the  experiment  of  Mayo  upon  the  latter 
nerve  after  it  had  emerged  upon  the  face,  and 
he  has  not  succeeded  in  obtaining  contraction 
of  the  facial  muscles  thereby,  while  the  strug- 
gles of  the  animal,  excited  by  the  irritation  of 
the  nerve,  proved  it  to  be  one  of  exquisite  sen- 
sibility. It  appears  then  to  the  author  impos- 
sible to  admit  that  the  facial  muscles  either 
possess  two  contractile  powers  dependent  on 
distinct  nerves,  or  that  they  derive  any  volun- 
tary power  from  the  fifth. 

It  is  extraordinary  that  Magendie,  who  was 
the  first  to  detect  the  error  into  which  Bell  had 
fallen  with  regard  to  the  influence  of  the  infra- 
orbital nerve  over  the  motions  of  the  muscles 

*  This  expression  has  been  used  because  the 
muscles  may  be  still  excited  to  contraction  by  irri- 
tation of  the  portion  of  the  nerve  connected  with 
them. 


of  the  face,  and  has,  according  to  his  own 
report,  divided  the  portio  dura  on  animals, 
should,  notwithstanding  all  that  has  been 
written  upon  the  subject,  have  adopted  the 
opinion  that  the  muscles  of  the  face  are  en- 
dowed with  the  two  distinct  faculties  of  motion, 
one  of  which  is  derived  from  the  fifth.  His  view 
will  be  found  at  page  703-4,  Anatomie  des 
Systemes  Nerveux,  &c,  and  the  opinion  there 
expressed  is  implied  in  a  note  at  page  191, 
Journal  de  Physiologie,  t.  x.  In  the  former 
he  says,  "  Now  Mr.  Charles  Bell  in  England 
and  M.  Magendie  in  France  by  cutting  the 
facial  nerve  have  paralyzed  the  respiratory 
motions  of  all  the  side  of  the  face  correspond- 
ing to  the  nerve  cut.  But  the  muscles  which 
receive  at  once  filaments  from  the  facial  nerve 
and  from  the  fifth  pair  were  paralyzed  only  in 
their  action  relative  to  respiration  and  to  the 
expression  of  the  physiognomy." 

The  influence  of  the  fifth  nerve  upon  the  tac- 
tile sensibility  of  the  parts  with  which  it  is  con- 
nected has  been  discussed  :  its  influence  upon 
their  ordinary  sensibility  also  requires  notice. 
From  the  preceding  details  it  appears  esta- 
blished that  it  is  to  the  same  nerve  that  this 
property  also  of  the  parts  in  general  is  due; 
but  there  is  reason  to  believe  that  the  nerve 
exerts  a  more  extended  control  over  this  faculty 
than  was  at  first  supposed.  At  the  commence- 
ment of  the  inquiries  into  the  functions  of  the 
nerves  of  the  face,  the  opinion  generally  held 
was  that  the  facial  nerve — portio  dura  of  the 
seventh  pair — was  devoid  of  sensibility.  Fur- 
ther observations,  however,  showed  that  this 
conclusion  was  erroneous,  and  that  the  insen- 
sibility to  any  injury  done  to  the  nerve  in 
question  manifested  by  the  subjects  of  experi- 
ment, and  from  which  the  inference  had  been 
drawn,  was  only  apparent,  and  to  be  referred 
to  the  constitution  of  the  individual  animal  or 
of  its  species.  The  sensibility  of  the  facial 
nerve  having  been  established,  a  question  arose, 
whether  that  property  was  independent  and 
proper  to  it,  or  whether  it  was  conferred  by 
another  ?  Those  who  first  observed  the  sensi- 
bility of  the  nerve  adopted  the  former  opinion  ; 
but  considerations  entitled  certainly  to  much 
weight  led  Eschricht  to  suspect  that  the  facial 
nerve  is  not  endowed  with  independent  sensi- 
bility, and  that  the  sensibility  which  is  manifested 
when  it  is  injured  is  conferred  on  it  by  the  fifth 
nerve.  In  order  to  determine  the  question  he 
performed  a  series  of  experiments  in  which  he 
divided  the  fifth  nerve  within  the  cranium  upon 
one  side  after  having  opened  the  cavity  and 
removed  so  much  of  the  corresponding  hemi- 
sphere of  the  brain  as  was  necessary  for  the 
accomplishment  of  his  purpose :  the  facial 
nerve  of  the  same  side  was  then  exposed,  and 
its  properties  tested.  The  faculties  of  the 
animal  are  so  little  affected  by  the  removal  of 
the  brain,  that  the  result  of  the  experiment 
seems  free  from  objection,  while  all  influence 
of  the  fifth  nerve  upon  the  sensibility  of  the 
facial  or  other  parts  must  be  destroyed.  In  his 
first  successful  experiment  irritation  of  the 
facial  excited  spasms  of  the  lips,  and  also  in- 
dications of  suffering  so  decided  that  a  doubt 


FIFTH  PAIR  OF  NERVES. 


305 


could  not  be  entertained  :  the  fifth  nerve  had 
also  been  fairly  divided:  thus  far,  therefore, 
his  conjecture  was  disproved.  Pursuing  his 
inquiry  still  further,  he  found  in  his  next 
experiment  that  no  indication  whatever  of  pain 
was  manifested  by  the  animal  on  irritation  of 
the  facial  on  the  side  on  which  the  fifth  nerve 
had  been  cut ;  but  in  two  succeeding  experi- 
ments he  ascertained  that  while  irritation  of  the 
nerve  anterior  to  the  meatus  auditorius  pro- 
duced no  other  effect  but  spasms  of  the  nasal 
and  labial  muscles,  when  exerted  posterior  to 
that  point  it  excited  manifest  evidence  of  suf- 
fering :  this  latter  circumstance  he  accounts  for 
by  the  communications  of  the  posterior  part  of 
the  facial  with  other  sentient  nerves  besides  the 
fifth,  and  he  has  come  to  the  conclusion  that  the 
former  nerve  is  not  endowed  with  independent 
sensibility,  but  that  it  derives  the  property  from 
the  fifth  and  other  sentient  nerves :  this  ques- 
tion, however,  requires  further  investigation.* 

Relation  of  the  fifth  pair  of  nerves  to  the 
special  senses. — The  organs  of  the  special  senses 
are  in  the  higher  classes  and  in  the  case  of 
smell,  sight,  and  hearing,  each  supplied  with 
nerves  from  at  least  two  sources.  Besides  the 
particular  nerves,  which  are  generally  consi- 
dered to  be  the  source  or  medium  of  the  spe- 
cial sense,  they  are  furnished  with  branches 
from  the  fifth  pair;  and  a  question  must,  at  the 
outset,  be  asked  in  regard  to  the  two  nerves 
derived  from  these  different  sources,  as  to 
which  is  to  be  considered  the  proper  nerve  of 
the  peculiar  sense  enjoyed  ?  In  connexion 
with  the  two  separate  nervous  supplies,  it  is 
also  to  be  observed  that  each  organ  enjoys  two 
kinds  of  sensibility,  viz.  the  special  sensibility, 
through  which  sensations  of  the  particular  sense 
are  received,  and  the  general  sensibility,  in 
which  the  several  organs  of  the  body  partici- 
pate, and  which  is  the  medium  through  which 
impressions  of  contact  are  conveyed.  The  exis- 
tence of  the  special  sense,  the  coincidence  of 
the  particidar  nerve,  the  impairment  or  loss 
of  the  special  function  uniformly  consequent 
upon  the  injury  or  destruction,  whether  by 
disease  or  otherwise,  of  that  nerve  ;  and  the 
community  both  of  function  and  distribution, 
displayed  by  the  nerve  from  which  the  organs 
of  the  senses  are  in  common  supplied,  have 
led  physiologists  generally  to  the  conclusion 
that  in  each  case  the  particular  nerve  is  the 
medium  of  the  special  sense,  and  that  the 
fifth  nerve  confers  upon  the  organs  of  the  spe- 
cial senses  general  sensibility  only.  The  con- 
clusion thus  commonly  adopted  has  been  at 
different  times  called  in  question  :  thus  Mery 
and  Brunet,  in  1697,  denied  to  the  nerves  of 
the  first  pair  the  function  of  smell,  and  attri- 

*  Eschricht,  de  functionibus  nervorum  faciei  et 
olfactus  organi,  Hafn.  1825.  |  The  superficial  tem- 
poral nerve  doubtless  contributes  mainly  to  supply 
sensibility  to  the  posterior  twigs  of  the  facial  :  but 
so  much  difficulty  do  some  see  in  satisfactorily 
accounting  for  the  sensibility  of  the  portio  dura, 
that  they  find  it  convenient  to  discover  two  roots  of 
oiigin,  and  a  ganglion  on  one,  thus  reducing  it  to 
the  class  of  compound  nerves.  See  Arnold,  Icones 
capitis  nervorum  ;  also  Gaedechcns,  nervi  facialis 
physiologia  et  pathologia. — En.] 
VOL.  II. 


buted  this  sense  to  the  fifth  nerve  *  The  ques- 
tion of  the  connexion  between  the  fifth  nerve 
and  the  special  senses  is  one  of  much  difficulty, 
and  probably  we  are  not  as  yet  in  possession  of 
sufficient  data  from  which  to  draw  a  positive 
conclusion  upon  it  when  viewed  in  all  its  bear- 
ings. It  resolves  itself  into  three:  1.  how  far 
the  nerve  may  be  concerned  in  the  perception 
of  special  sensations  in  those  cases  in  which 
nerves,  considered  to  be  specially  intended  for 
their  perception,  exist:  2.  how  far  its  co- 
operation or  influence  may  be  necessary  to 
enable  the  special  nerves  to  fulfil  their  func- 
tions: 3.  how  far  it  may  be  capable  of  taking 
the  place  of  those  special  nerves,  and  of  be- 
coming, under  certain  conditions,  media  of 
perception  to  sensations,  for  which,  in  other 
cases,  peculiar  nerves  are  conferred.  We  shall 
review  the  relation  of  the  nerve  to  the  several 
senses  in  succession,  bearing  in  mind  the  three 
points  to  which  our  attention  is  to  be  directed. 
That  it  is  a  medium  of  perception  in  the  case 
of  two  senses,  viz.  touch  and  taste,  is  already 
so  universally  acknowledged  that  it  is  unneces- 
sary to  dwell  upon  the  point. 

The  importance  of  the  fifth  nerve  in  the 
three  other  senses  of  smell,  sight,  and  hearing, 
has  been  advocated  by  several  physiologists, 
and  more  particularly  by  Magendie,  who  ap- 
pears disposed  to  view  the  fifth  nerve  as  the 
source  or  medium  of  all  the  three.  His  appli- 
cation of  this  doctrine,  however,  has  reference 
more  particularly  to  the  sense  of  smelling, 
upon  which  he  has  performed  a  series  of  expe- 
riments, of  which  the  following  is  a  summary : 
he  destroyed  entirely  the  olfactory  nerves  within 
the  cranium,  and  he  found  the  animal  still 
sensible  to  strong  odours,  such  as  ammonia, 
acetic  acid,  essential  oil  of  lavender.  The  sen- 
sibility of  the  interior  of  the  nasal  cavity  had 
lost  nothing  of  its  energy;  the  introduction  of 
a  stylet  had  the  same  effect  as  upon  a  dog 
which  had  not  been  touched.  This  experiment 
he  performed  several  times,  and  always  with 
the  same  results.  He  next  divided  the  fifth 
nerves  within  the  cranium,  of  course  before 
they  had  given  branches  to  the  nostrils, 
and  found  all  trace  of  the  action  of  strong 
odours  to  disappear.  He  hence  concluded  that 
smell,  in  so  far  as  pungent  smells  are  con- 
cerned, is  exercised  by  the  branches  of  the 
fifth  pair,  and  that  the  first  is  not  concerned  in 
the  function.  To  this  conclusion  he  himseli 
starts  the  objection  that  the  agents  used  are  not 
odours,  properly  speaking,  but  chemical,  pun- 
gent, irritating  vapours,  and  that  by  the  section 
of  the  fifth  we  destroy  not  the  sense  of  smell, 
but  only  the  sensibility  of  the  membrane  of  the 
nose  to  these  irritating  vapours,  and  he  admits 
the  force  of  the  objection  with  respect  to  some 
of  the  vapours  alluded  to  ;  but  he  denies  that 
it  will  apply  to  the  oil  of  lavender  or  that  of 
Dippel,  the  effect  of  which  in  the  experiments 
is  the  same.  In  order  to  remove  the  difficulty 
he  destroyed  the  olfactory  nerves  of  a  dog  of 
particularly  fine  nose,  and  then  enclosing  por- 
tions of  food  of  various  kinds  in  paper,  he 

*  See  Journal  Complementaire,  v.  20. 

x 


306 


FIFTH  PAIR  OF  NERVES. 


presented  them  to  the  animal,  and  it  always 
undid  the  paper  and  possessed  itself  of  the 
food ;  but,  he  adds,  "  I  do  not  regard  this  ex- 
periment as  satisfactory,  because  in  other  cir- 
cumstances it  appeared  to  me  to  want  smell  to 
discover  food  which  I  put  near  him  without 
his  knowledge"  (a  son  insu ).  However,  the 
latter  circumstance  is  overlooked  by  Magendie, 
and  his  conclusion  is,  "  une  fois  le  nerf  trifa- 
cial coupe,  toute  trace  de  sensibilite  disparait, 
aucun  corps  odorant  a  distance  ou  en  contact, 
les  corrosifs  memes  n'affectent  plus  en  aucune 
facon  la  pituitaire."*  Doubtless  this  conclu- 
sion is  qualified  by  another  immediately  suc- 
ceeding, "  that  does  not  prove  that  the  seat  of 
smell  is  in  the  branches  of  the  fifth  pair;  but 
it  proves  at  least  that  the  olfactory  nerve  has  an 
indispensable  need  of  the  branches  of  the  fifth 
pair  to  be  able  to  enter  into  action  ;  that  it  is 
devoid  of  general  sensibility,  and  that  it  can 
have  only  a  special  sensibility  relative  to 
odorous  bodies. "\  The  latter  must  be  ad- 
mitted to  come,  if  not  quite,  at  least  very  near 
to  the  general  opinion,  but  it  is  altogether  at 
variance  with  the  former,  and  one  is  rather  at 
fault  for  the  author's  precise  meaning.  Refe- 
rence to  later  writings,  however,  leaves  no 
doubt  upon  that  point.  In  the  conjoint  work 
of  Desmoulins  and  Magendie  (1825)  upon  the 
nervous  system  of  the  vertebrata,  besides  other 
similar  passages,  will  be  found  the  following: 
"  La  cinquicme  paire,  par  ses  branches  nasales 
dans  les  mammiferes,  et  par  ses  branches  pro- 
pres  a  la  cavite  pre-oculaire  des  trigonocephales 
et  des  serpents  a  sonnettes,  est  done  l'organe 
de  l'odorat."J  Notwithstanding  the  weight  of 
Magendie's  authority,  a  careful  review  of  the 
matter  will  not  permit  us  to  assent  to  this  con- 
clusion, and  compels  us  to  avow  not  only  that 
it  is  not  proved,  but  that  the  premises  justify 
a  contrary  one.  In  the  first  place  it  is  not  war- 
rantable to  call  the  effluvia  of  ammonia  or 
acetic  acid  odours :  they  are  no  more  odours 
than  the  fumes  of  muriatic  or  nitric  acid  ;  and, 
though  aware  of  the  objection,  he  still  calls 
them  odeurs  fortes,  and  bases  his  inference 
upon  their  operation.  But  he  says  the  objec- 
tion does  not  apply  to  oil  of  lavender  or  the 
animal  oil  of  Dippel :  this,  however,  is  but  an 
assumption  at  variance  with  fact;  in  the  human 
subject  these  agents  may  act  feebly  upon  the 
sensibility  of  the  membrane  of  the  nostrils,  and 
may  not  appear  to  possess  irritating  properties ; 
but  this  will  not  prove  that  they  act  similarly 
upon  animals,  whose  organ  of  smell  is  more 
sensitive  than  that  of  man,  and  accordingly 
Dr.  Eschricht,§  who  combats  the  opinion  of 
Magendie,  has  found  that,  on  application  to 
the  nostrils  of  those  animals  upon  which  the 
experiments  of  Magendie  have  been  performed, 
they  produce  all  the  same  effects  which  am- 
monia or  nitric  acid  does.  In  the  second  place 
his  experiment  of  presenting  food  to  a  dog, 
whose  olfactories  had  been  destroyed,  enclosed 

*  Journal  de  Physiologie,  t.  iv.  p.  306. 
t  Ibid. 

t  T.  ii.  p.  712. 

§  Journal  de  Physiologie,  t.  »i.  p.  350. 


in  paper,  and  in  which  the  animal  undid  the 
paper,  upon  his  own  showing  not  only  does 
not  justify  his  inference,  but,  so  far  as  it 
reaches,  proves  the  contrary.  To  establish  his 
position  the  animal  must  have  discovered  the 
food  by  smell,  without  knowing  that  it  was  in 
the  paper;  but  it  is  manifest,  from  Magendie's 
own  relation,  that  when  the  animal  undid  the 
paper,  it  knew,  or  was  led  by  some  circum- 
stance to  expect  the  food  to  be  in  it ;  but  that 
when  it  was  not  already  aware  or  in  expecta- 
tion that  the  food  was  near  it,  it  did  not  dis- 
cover it.  To  the  writer  it  seems  that  the  na- 
tural inference  from  the  experiment,  as  related, 
is  that  the  animal's  proper  sense  of  smell  de- 
pended upon  the  olfactory  nerves,  inasmuch  as 
it  did  not  display  fair  evidence  of  its  presence 
after  their  destruction,  and  that  the  sensibility 
displayed  by  the  membrane  of  the  nostrils  after 
the  destruction  of  these  nerves,  and  dependent 
upon  the  fifth,  has  reference  only  to  those  im- 
pressions which  are  objects  of  tactile  or  general 
sensation,  but  not  of  the  special  sense. 

At  the  same  time,  however,  that  we  express 
our  dissent  from  Magendie  with  regard  to  the 
nervous  connexion  of  the  proper  sense  of  smell, 
it  must  be  admitted  that  his  researches  posi- 
tively indicate  a  distinction  between  the  media 
of  perception  in  the  case  of  different  agents 
operating  on  the  olfactory  organ,  which  it  has 
been  too  much  the  habit  to  regard  as  pro- 
ducing their  impressions  all  through  the  olfac- 
tory nerves :  they  have  gone  a  considerable  way 
in  demonstrating  the  separation  of  those  media; 
a  result  which  is  made  complete  by  the  conti- 
nuance of  the  simple  sense  after  the  loss  of  the 
influence  of  the  fifth  nerve  consequent  upon 
disease :  further,  they  indicate  that  sensations 
derived  through  the  organ  of  smell  are  less 
simple  than  they  are  usually  accounted  ;  that 
they  may  be,  and  probably  are  for  the  most 
part,  compound,  resulting  from  the  combina- 
tion of  impressions  made  upon  the  two  senses 
thus  shewn  to  be  enjoyed  by  the  organ. 

Magendie's  view  has  been  adopted,  and  an 
endeavour  made  to  corroborate  and  establish  it 
by  Desmoulins  in  '  Reflexions'  upon  a  case 
communicated  by  Beclard,  and  published  in 
the  fifth  volume  of  the  Journal  of  Physiology. 
The  case  is  that  of  a  patient,  in  whom  the 
olfactory  nerves  and  their  bulbs  were  de- 
stroyed by  the  growth  of  a  tubercular  disease 
from  the  anterior  lobes  of  the  brain  ;  "  yet  he 
took  snuff  with  pleasure,  appeared  to  distin- 
guish its  different  qualities,  and  was  affected 
disagreeably  by  the  smell  of  the  suppuration  of 
an  abscess  with  which  one  of  his  neighbours 
was  afflicted."  From  this  case,  from  that  of 
Series,  related  elsewhere,  and  the  experiments 
of  Magendie  viewed  in  connexion,  Desmoulins 
has  adopted  the  opinion  that  "  the  nerves  and 
lobes  called  olfactory  are  alien  to  the  sense  of 
smell,  or  at  all  events  co-operate  so  little  in  it, 
that  the  sense  continues  to  be  exerted  without 
them  ;  that,  on  the  contrary,  this  sense  resides 
essentially  in  the  branches  of  the  fifth  pair, 
which  are  distributed  to  the  nostrils."  Serres' 
case  has  been  discussed  elsewhere;  that  of 
Beclard  appears  at  first  unanswerable ;  but 


FIFTH  PAIR  OF  NERVES. 


307 


how  will  it  appear  after  the  qualification  by 
which  it  is  followed  has  been  perused  ?  "  I 
owe  it  to  truth,"  he  says,  "  to  add  that  these 
last  statements  were  not  collected  till  after  the 
dissection,  and  that  they  were  gathered  from 
the  patients  of  the  ward."  Such  an  admission 
manifestly  destroys  the  value  of  the  case  :  evi- 
dence obtained  only  after  the  individual's  death, 
so  little  marked  as  during  his  lifetime  to  have 
been  overlooked,  and  relating  to  a  question  at 
once  so  obscure  and  delicate,  can  hardly  fail  to 
be  imperfect;  but  admitting  that  the  patient 
did  relish  and  distinguish  between  different 
kinds  of  snuff,  and  that  he  was  disagreeably 
affected  by  his  neighbour's  ailment,  what  then? 
The  chief  property  of  common,  if  not  of  every 
snuff,  is  pungency  and  not  odour,  and  the  per- 
ception of  pungency  is  not  the  function  of  the 
olfactory  nerve;  and  one  may  be  as  disagree- 
ably affected  by  a  disgusting  sight  as  by  a  dis- 
gusting smell,  and  the  patients  of  the  ward  not 
make  any  distinction  between  the  senses  af- 
fected, until  taught  by  the  inquiries  made  that 
it  must  have  been  that  of  smell.  And  if  the 
case  just  quoted  prove  the  existence  in  the 
organ  of  smell  of  a  sensibility  to  the  impres- 
sion of  volatile  agents  independent  of  the  ol- 
factory, and  conferred  by  the  fifth  nerve,  the 
existence  of  another  equally  independent  of 
the  latter  is  satisfactorily  established  by  the 
continuance  of  smell  in  those  cases  in  which 
the  faculty  conferred  by  the  fifth  nerve  has  been 
lost  through  disease.  This  may  be  seen  from 
reference  to  the  case  furnished  by  Beclard,  and 
advanced  by  the  very  advocates  of  Magendie's 
doctrine  in  support  of  it;  but  the  fact  is  still 
more  strongly  established  by  the  case  some 
time  since  published  by  Mr.  Bishop,  in  which, 
though  the  fifth  nerve  was  completely  destroyed 
by  the  pressure  of  a  tumour  within  the  cra- 
nium, and  both  the  ordinary  and  tactile  sensi- 
bility of  the  same  side  of  the  face  and  its  cavi- 
ties was  in  consequence  altogether  lost,  the 
sense  of  smell  continued  unimpaired.  In  a 
case  of  disease  of  the  fifth  nerve  which  the 
writer  has  witnessed,  the  patient  did  acknow- 
ledge the  perception  of  certain  odoriferous 
agents ;  but  judging  from  it  alone,  he  could 
not  say  that  smell  was  not  impaired ;  on  the 
contrary  it  seemed  very  much  so,  inasmuch  as 
the  patient  denied  at  first  any  perception  of 
the  impression  of  several  agents  accounled 
odorous,  and  when  he  did  say  that  he  smelt 
these,  it  was  not  of  himself,  nor  until  he  had 
been  particularly  questioned,  and  then  he  said 
it  was  *  up  in  his  head'  that  he  felt  the  sensa- 
tion, and  positive  must  take  precedence  of  nega- 
tive evidence.  Further,  it  is  very  likely  that  in 
the  case  of  sensations,  themselves  neither  dis- 
agreeable nor  acute,  the  vividness  of  which 
may  depend  very  much  upon  association  with 
other  and  more  acute  ones,  the  former  may  be 
disregarded  where  the  latter  have  been  lost, 
and  hence  the  rashness  of  inferring  that  brutes 
have  lost  certain  faculties,  because  in  the  course 
of  experiments  they  do  not  by  the  exercise  of 
these  give  evidence  of  their  existence.  The 
fact  of  the  absence  of  olfactory  nerves  in  the 
Cetacea  as  established  by  Cuvier  has  also  led 


some  to  the  conclusion  that  the  proper  faculty 
of  smell  may  be  capable  of  being  transferred 
at  least  to  the  fifth ;  but  until  the  faculty  has 
been  proved  to  exist  in  such  case,  the  inference 
is  manifestly  not  warranted  by  the  premises. 

It  appears  then  that  there  is  a  distinct  per- 
ceptive faculty  enjoyed  by  the  nostrils,  inde- 
pendent of  the  fifth  and  dependent  on  the 
olfactory  nerve;  that  we  possess  no  positive 
evidence  of  the  latter  nerves  being  in  any  case 
the  media  by  which  this  peculiar  perception  is 
recognized,  but  that  they  serve  for  the  recogni- 
tion only  of  impressions  of  contact,  pungency, 
or  irritation. 

2.  Relation  of  the  fifth  nerves  to  vision. — • 
That  in  all  animals  having  at  once  the  faculty 
of  vision  and  an  optic  nerve,  the  latter  is  in- 
dispensably necessary  to  the  exercise  of  the 
former  cannot  be  denied  : — disease  or  division 
of  the  nerve  is  uniformly  attended  by  loss  of 
the  function  ;  but  some  circumstances  coun- 
tenance the  opinion  that  the  fifth  nerve  pos- 
sesses a  more  important  connection  with  vision 
than  may  at  first  appear.  1.  Injury  of  the 
frontal  and  certain  other  branches  of  the  fifth 
nerve  has  been  long  accounted  among  the 
causes  of  amaurosis.  2.  Maj;eiidie  has  found 
that  "  on  division  of  the  two  '  fifth  '  nerves 
upon  an  animal  it  seems  blind."  3.  The  fact 
which  countenances  most  strongly  the  opinion 
that  the  fifth  nerve  is  concerned  directly  in 
the  function  of  vision  is  derived  from  com- 
parative anatomy.  It  has  been  stated  that  in 
certain  animals  a  special  optic  nerve  is  wanting, 
and  the  ocular  nerve  is  derived  from  the  fifth 
pair.  Of  this  it  appears  universally  admitted 
that  the  proteus  anguinus  is  an  instance;  its 
eyes  are  situate  immediately  beneath  the  epi- 
dermis, which  is  transparent  *  in  front  of  them  ; 
the  optic  nerve  is  wanting,-)-  and  the  only  nerve 
received  by  the  eye  is  a  branch  of  the  second 
division  of  the  fifth. \  Whatever  vision,  there- 
fore, may  be  enjoyed  by  this  animal,  and 
according  to  Carus§  it  is  considerable,  must 
be  exerted  through  the  medium  of  the  fifth 
nerve.  Among  the  mammalia  also  are  several 
animals  which  appear  to  be  in  the  same,  or 
nearly  the  same  state  ;  but  anatomists  are  not 
agreed  on  the  point :  the  absence  of  a  special 
optic  nerve  in  the  mole  was  announced  by 
Zinn,  ||  who  shewed  that  its  place  was  taken  by 
a  branch  of  the  fifth.  Carus  and  Treviranus, 
however,  maintain  that  the  optic  does  exist 
in  the  animal,  but  that  it  is  very  minute,  grey, 
and  capillary ;  that  in  the  same  proportion 
the  fifth  nerve  is  large,  and  that  its  second 
division  at  its  exit  from  the  cranium  gives 
off  a  branch,  which  enters  the  globe  of  the 
eye,  and  according  to  the  former  concurs  in 
forming  the  retina.lf  Serres  again  positively 
denies  the  existence  of  the  optic  nerve  in  the 
mole,  and  maintains  that  these  anatomists  are 
mistaken ;  he  states  that  he  has  sought  the 

*  Serres. 

t  Treviranus,  Serres. 
X  Ibid. 

§  Comparative  Anatomy. 

[I  De  differentia  fabricae  oculi  humani  et  brntorum. 
Tl  Journal  Complementaire,  vol.  xv. 

x  2 


308 


FIFTH  PAIR.  OF  NERVES. 


nerve  with  the  greatest  care  in  thirty  or  forty 
of  these  animals,  and  never  succeeded  in 
finding  it;  and  also  in  confirmation  thereof 
that  the   optic   foramen  is  wanting  in  the 
sphenoid  bone.     According  to   him  several 
other  of  the  mammalia  are  similarly  constituted, 
viz.  the  mus  typhlus,  the  mus  capensis,  the 
chrysochlore,  and  the  sorex  araneus.    Of  these 
the  mole,  the  mus  capensis,  and  the  sorex 
arensis  decidedly  enjoy  vision,  the  first  ac- 
cording to  the  observations  of  Geoffroy  St. 
Hilaiie  and  Cuvier ;  the  second  according  to 
those  of  Uelalande,  and  the  third  according 
to  Series  himself ;   and  if  his  view  of  the 
anatomical  disposition  of  their  ocular  nerve 
be  correct,  the  fifth  nerve  must  in  them  also 
take  the  place  of  the  optic  and  serve  as  the 
medium   of  sight.     Treviranus,  though  he 
maintains  the  existence  of  a  special  nerve  in 
the  mole,  yet  says,  from  the  disproportion 
of  the  optic  and  the  ocular  branch  of  the 
fifth,  that  in  that  animal  the  latter  ought  or 
must  have  to  fulfil  in  vision  more  important 
functions  than  the  optic  nerve.*     When  to 
these  facts  we  add  the  view  of  the  nervous 
connections  of  the  senses  in  invertebrate  animals 
advocated  by  Treviranus,  viz.  that  the  nerves  of 
the  senses  in  them  are  all  branches  of  the  fifth 
pair,  the  general  proposition  seems  sufficiently 
probable,  viz.  that  the  fifth  nerve  is  capable  of 
acting  as  a  medium  of  perception  to  impressions 
of  light.    But  on  the  one  hand,  until  it  be 
proved  what  the  exact  nature  of  the  optic 
faculty  is  which  animals  devoid  of  a  special 
optic  nerve  possess,  the  question  must  be  held 
to  be  undecided.    It  may  be  that  the  faculty 
is  different  in  the  two  cases ;  that  where  the 
special  nerve  is  absent,  the  faculty  may  amount, 
as  suggested  by  Treviranus,  to  no  more  than 
a  mere  perception  of  light,  and  that  the  im- 
pression is  then  not  visual,  but  only  one  of 
ordinary  sensibility.    Such  a  distinction,  in 
the  sense  in  which  that  term  is  understood 
in  reference  to  the  higher  animals,  is  easily 
conceived,  and  indeed  is  demonstrable  from 
the  influence  of  light  upon  an  inflamed  or 
irritable  eye,  and  if  such   a  distinction  do 
naturally  exist,  the  apparent  anomaly  presented 
by  animals  being  sensible  of  light  and  seeming 
to  enjoy  vision  without  a  special  optic  nerve 
will  be  removed,  while  such  a  faculty  may 
suffice  fully  for  the  condition  of  the  animal. 
Again,  the  evidence  in  favour  of  the  opinion 
that  the  fifth  is  directly  concerned  in  vision 
where  a  special  nerve  exists,  seems  altogether 
insufficient.     In  the  first   place,  though  in- 
juries involving  the  frontal  or  other  branches 
of  the  fifth  nerve  may  induce  amaurosis,  it 
remains  to  be  proved  that  the  injury  of  the 
nerve  is  the  cause  of  the  disease,  and  that 
this  did  not  rather  arise  from  the  effect  of  the 
injury  upon  other  parts  concerned  in  vision; 
a  view  which  is  greatly  confirmed  by  the  fact 
that  the'  mere  section  of  the  nerve  has  not 
been  found  to  occasion  any  such  affection  of 
vision.    In  the  second  place  the  experiments 
of  Magendie  are  far  from  satisfactory.  In 

*  Ibid.  vol.  xv.  p.  210. 


order  to  determine  the  influence  of  the  fifth 
nerve  upon  vision,  he  performed  the  following 
experiments,  from  which  he  inferred  that  the 
section  of  the  fifth  nerve  destroys  sight  without 
abolishing  entirely  all  sensibility  of  the  eye 
for  light,  and  suggests  in  explanation  either 
that  the  fifth  is  the  medium  of  perception,  or 
that  it  is  necessary  to  enable  the  optic  to  act. 
After  having  divided  the  fifth  pair  on  one 
side  in  rabbits,  he  threw  suddenly  upon  the 
eye  the  light  of  a  wax  candle,  and  no  effect 
was  produced ;  the  same  being  tried  upon  the 
sound  eye,  the  only  effect  produced  was  move- 
ments of  the  iris.  Under  the  impression  that 
this  was  not  sufficiently  intense,  he  tried  that 
of  a  powerful  lamp,  but,  even  with  the  as- 
sistance of  a  lens,  the  result  was  the  same. 
He  then  tried  the  experiment  with  solar  light, 
and  by  making  the  eye  pass  suddenly  from 
the  shade  to  the  direct  light  of  the  sun,  an 
impression  was  produced  and  the  animal  im- 
mediately closed  its  eyelids.  Such  data  cannot 
be  admitted  as  sufficient  to  justify  the  inference 
that  vision  is  destroyed  by  the  section  of  the  fifth 
nerve.  In  the  first  place  it  is  to  be  recollected 
that  the  experiment  was  made  upon  rabbits,  in 
which  Magendie  has  elsewhere  told  us  that 
section  of  the  fifth  nerve  produces  strong  con- 
traction of  the  iris,  consequently  great  dimi- 
nution of  the  size  of  the  pupil :  and  of  what 
value,  then,  is  the  result  that,  under  the  in- 
fluence of  the  light  of  a  candle  or  a  lamp,  an 
impression  was  not  made  sufficiently  powerful 
to  cause  the  animal  to  give  evidence  of  it? 
In  the  second  place  the  animal  did,  under  all 
the  disadvantages,  give  sufficient  evidence  that 
its  vision  was  not  destroyed ;  there  is,  therefore, 
no  reason  for  the  conclusion  drawn  from  the 
experiment  related. 

On  the  other  hand.  Mayo  has  found  that 
the  fifth  nerve  may  be  divided  within  the 
cranium  in  the  cat  and  pigeon,  and  vision 
continue  unaffected;  which  circumstance  shows 
that  the  apparent  loss  of  vision  in  the  rabbit 
was  owing  to  the  great  contraction  of  the  pupil, 
while  according  to  Magendie's  statement  there 
does  not  remain  any  trace  whatever  of  sensi- 
bility to  the  impression  of  light  in  the  eye 
after  the  section  of  the  optic  nerve.  We  must, 
then,  conclude  that  the  optic  nerve  is  the 
proper  medium  of  perception  to  visual  im- 
pressions, and  that  the  co-operation  of  the  fifth 
nerve  is  not  even  necessary  to  enable  the  optic 
nerve  to  fulfil  its  function.  As  the  instrument 
of  the  general  sensibility  of  the  structures  of 
the  eye,  however,  the  fifth  nerve  may  be  the 
channel  through  which  impressions  not  visual, 
though  perhaps  excited  by  an  agent  of  vision, 
viz.  light,  may  be  conveyed. 

The  conclusion  thus  drawn  from  experimental 
physiology  is  fully  confirmed  in  man  by  the 
history  of  those  cases  in  which  the  influence 
of  the  fifth  nerve  has  been  lost  from  disease  : 
of  these  two  have  been  adduced  by  Bell  in 
the  Philosophical  Transactions  for  1823,  one 
from  the  observation  of  Mr.  Crampton,  the 
other  from  that  of  Dr.  Macmichael,  in  which 
the  surface  of  the  eye  was  totally  insensible, 
whilst  vision  was  entire ;  and  another,  still 


FIFTH  PAIR  OF  NERVES. 


309 


more  remarkable,  has  been  reported  by  Mr. 
Bishop,*  in  which  the  functions  of  the  fifth 
nerve  seemed  altogether  obliterated  by  the 
pressure  of  a  diseased  growth  within  the 
cranium,  and  yet  the  patient  saw  distinctly 
to  the  last,  the  only  derangement  which  oc- 
curred in  the  function  of  vision  being  the  loss 
of  the  power  of  distinguishing  colours,  which 
appears  sufficiently  accounted  for  by  a  certain 
degree  of  pressure  exerted  by  the  tumour  upon 
the  optic  nerve.  Magendie  endeavours  to 
support  his  views  upon  this  and  other  points 
connected  with  the  properties  of  the  nerve  by 
reference  to  a  case  reported  by  Serres,  which 
appears  very  inadequate,  and  will  be  discussed 
by-and-bye. 

Influence  of  the  fifth  nerve  on  hearing. — 
The  great  affinity  between  the  sense  of  hearing 
and  that  of  touch  renders  it  more  easy  to 
conceive  how  hearing  might  be  excited  through 
the  medium  of  the  fifth  nerve.  As  we  have 
seen  that  the  ocular  nerve  in  certain  animals  is 
a  branch  of  the  fifth  nerve,  so  is  the  auditory. 
Among  the  cartilaginous  fishes  there  are  several 
instances  in  which  this  occurs.  The  origin  of 
the  auditory  nerve  from  the  fifth  in  fishes  was 
first  announced  by  Scarpa,-)-  and  by  him  sup- 
posed to  apply  to  fish  generally.  This  view 
is  combated  by  Treviranus:J  it  is  admitted 
in  part  by  Serres ;  he  states  that  in  osseous 
fishes  the  auditory  nerve  is  united  at  its  in- 
sertion with  the  fifth;  in  cartilaginous  fishes, 
that  thp  auditory  is  sometimes  confounded 
with  th^  fifth,  sometimes  separated  distinctly 
enough,  as  in  the  raia'clavata.  From  his  own 
observations  the  writer  would  say,  that  in  the 
bony  fishes  the  two  nerves  cannot  be  said  to 
be  united  or  to  arise  the  one  from  the  other, 
but  only  to  have  a  common  superficial  attach- 
ment to  the  medulla  oblongata ;  and  from  the 
analogy  of  the  same  nerves  in  the  higher  classes 
of  animals,  he  would  not  admit,  without 
further  proof,  a  common  superficial  attachment 
as  establishing  identity  of  ultimate  connection 
with  the  encephalon.  As  to  the  cartilaginous 
fishes,  it  appears  to  him  that  Serres  has  fallen 
into  an  error  with  regard  to  the  connection  of 
the  auditory  nerve.  It  appears  to  the  writer 
that  the  fifth  and  the  auditory  are  con- 
founded in  the  raia  clavata  as  plainly  as  in 
any  other  individual  of  the  class ;  the  posterior 
ganglionic  fasciculus  of  the  fifth  and  the 
auditory  nerve  form  one  trunk  for  a  distance 
of  some  lines  after  leaving  the  medulla  ob- 
longata ;  they  are  at  all  events  enclosed  within 
the  same  sheath :  §  but  whether  they  are  to  be 
regarded  as  branches  of  a  common  trunk  or 
not,  it  is  difficult  to  decide.  The  weight  of 
naalogy  is  certainly  opposed  to  a  conclusion 

*  Medical  Gazette,  vol.  xvii. 
t  De  Audita  et  Olfactu. 
1  Journ.  Compl. 

§  Serres  seems  to  have  overlooked  the  fact  that 
there  exist  two  ganglionic  fasciculi  in  the  raia 
clavata  ;  that  he  has  assumed  the  anterior  fasci- 
culus to  be  the  fifth,  and  described  the  posterior, 
with  which  the  auditory  is  connected,  as  the  auditory 
and  facial  nerves  :  the  error  will  be  manifest  upon 
tracing  the  distribution  of  the  fasciculus. 


in  the  affirmative ;  and,  though  this  were  ad- 
mitted, a  difference  between  the  auditory  and 
the  other  branches  of  the  fifth  (as  supposed) 
must  still  be  admitted,  inasmuch  as  the  auditory 
separates  from  the  nerve  before  the  occurrence 
of  the  ganglion,  and  has  not  itself  a  ganglion. 
On  the  other  hand  the  auditory  may  be  se- 
parated from  the  rest  of  the  nerve,  after  the 
division  of  the  common  investing  membrane, 
with  little  or  no  laceration  of  fibres.  Still  it 
may  be  asked  why,  if  they  be  distinct  nerves, 
are  they  united  into  one  trunk?  The  opinion 
that  the  fifth  nerve  holds  an  important  in- 
fluence over  the  sense  of  hearing  derives  support 
from  the  circumstance,  that  in  most,  if  not 
all,  the  cases  of  disease  of  the  nerve,  the 
sense  of  hearing  becomes  impaired,  though 
not  obliterated. 

The  last  question  proposed  to  be  considered 
with  reference  to  the  functions  of  the  fifth 
nerve  is  its  connection  with  nutrition. 

The  opinion  that  the  nerve  controls  the 
nutrition  of  the  parts  which  it  supplies  has 
been  advocated  by  Magendie,  more  particularly 
with  regard  to  the  eye.  It  has  been  already 
stated  that  we  are  indebted  to  this  writer  for 
information  in  regard  to  results  of  the  division 
of  the  entire  trunk  of  the  nerve  within  the 
cranium.  Of  these  the  most  prominent  is 
the  entire  loss  of  sensibility  on  the  same 
side  of  the  face,  and  in  regard  to  the  eye 
especially,  loss  of  sensibility  in  the  conjunc- 
tiva, upon  which  the  most  irritating  chemical 
agents  then  produce  no  impression.  These 
immediate  effects  of  the  section  were  followed 
by  others  not  less  remarkable :  on  the  next 
day  the  sound  eye  was  found  inflamed  by 
the  ammonia,  which  had  been  applied  to  it, 
while  the  other  presented  no  trace  of  inflam- 
mation. Other  changes,  however,  supervene. 
The  cornea  of  the  eye  of  the  side  on  which 
the  section  is  made,  twenty-four  hours  after- 
wards begins  to  become  opaque ;  after  seventy- 
two  it  is  much  more  so  ;  and  five  or  six  days 
after  it  is  as  white  as  alabaster.  On  the  second 
day  the  conjunctiva  becomes  red,  inflames, 
and  secretes  a  puriform  matter.  About  the 
second  day  the  iris  also  becomes  red  and  in- 
flames, and  false  membranes  are  formed  upon 
its  surface.  Finally  the  cornea  ulcerates,  the 
humours  of  the  eye  escape,  and  the  globe 
contracts  into  a  small  tubercle.  In  endeavouring 
to  ascertain  the  cause  of  these  changes,  Ma- 
gendie, on  the  supposition  that  they  might 
be  owing  either  to  the  continued  exposure  of 
the  eye  to  the  air  or  to  the  want  of  the 
lachrymal  secretion,  divided  the  portio  dura 
in  one  rabbit,  the  effect  of  which  is  to  destroy 
the  power  of  closing  the  eyelids ;  and  from 
others  he  cut  out  the  lachrymal  gland ;  but 
in  neither  case  did  opacity  of  the  cornea  suc- 
ceed. The  sequence  of  the  effects  mentioned 
after  the  section  of  the  nerve  might  naturally 
lead  us  to  infer  that  the  loss  of  nervous  in- 
fluence gives  rise  to  them.  But  such  is  not 
the  inference  drawn  by  Magendie,  nor  indeed 
can  it  be  admitted  :  absence  or  subtraction 
of  an  influence  cannot  be  directly  the  cause 
of  an  alteration  in  the  condition  of  an  object 


310 


FIFTH  PAIR  OF  NERVES. 


otherwise  than  by  allowing  it  to  come  or  return 
to  a  state  from  which  it  is  preserved  by  the 
presence  of  the  influence ;  and  there  is  no 
good  reason,  either  theoretical  or  experimental, 
for  believing  that  the  state  induced  in  the 
case  under  consideration  is  one  in  which  the 
eye  would  necessarily  be,  which,  in  fact, 
would  be  natural  to  the  organ  but  for  the 
restraining  influence  exerted  through  the  fifth 
nerve. 

It  is  easy  to  imagine  that  the  absence  of 
such  an  influence  should  render  a  part  slow  to 
take  on  any  vital  action  ;  though  even  this, 
until  proved,  is  an  assumption — an  assumption 
which  we  are  induced  to  adopt  from  the  fre- 
quency with  which  sensation  and  pain  are 
found  associated  with  the  establishment  of  cer- 
tain vital  processes,  more  particularly  inflam- 
mation, but  which  is,  on  the  other  hand,  con- 
tradicted by  the  readiness  with  which  inflam- 
mation and  its  consequences  are  excited  in 
parts  whose  nervous  faculties  are  impaired  or 
destroyed  by  agencies  which  make  little  or  no 
impression  when  those  faculties  are  retained, 
and  which  must  be  demonstrated  before  admit- 
ted, since  it  is  manifest  from  the  occurrence  of 
that  process  after  the  destruction  of  all  trans- 
mitted influence  at  least,  that  the  principle — 
the  main-spring  of  it  must  reside  elsewhere; 
and  hence  that,  if  in  the  natural  state  the  nerve 
influence  the  process  at  all  by  means  of  such  a 
property,  it  can  be  only  in  the  character  of  a 
secondary  and  controlling  power.  It  does, 
however,  seem  proved  by  the  result  of  Magen- 
die's  experiment,  that  the  interruption  of  the 
influence  did  retard  the  inflammatory  process, 
inasmuch  as  the  eye,  on  the  side  of  the  undi- 
vided nerve,  was  very  actively  inflamed  the  day 
after  the  application  of  ammonia  to  it,  whilst 
the  other  eye  did  not  present  any  trace  of  in- 
flammation ;  a  circumstance  by  the  way  diffi- 
cult, if  not  impossible,  to  reconcile  with  the 
doctrine  that  the  process  of  inflammation  is 
directly  influenced  in  either  way,  whether  posi- 
tively or  negatively,  by  the  power  of  the  nerve ; 
and  further,  that  the  division  of  the  nerve 
should  diminish  the  vital  powers  of  the  eye, 
and  thereby  render  it  less  able  to  resist  the 
effects  which  inflammatory  action  tends  to  pro- 
duce. But  indeed  there  does  not  appear  any 
reason  for  admitting  that  the  alterations  which 
took  place  in  the  condition  of  the  eye  were 
produced  directly  by  the  loss  of  nervous  influ- 
ence. Having,  as  he  conceived,  disproved,  by 
the  experiment  related,  the  idea  that  the  alte- 
rations were  owing  to  the  continued  exposure 
of  the  eye  to  the  air,  or  to  the  want  of  the 
lachrymal  secretion, — the  only  other  causes 
which  appear  to  have  occurred  to  him, — Ma- 
gendie  arrived  at  a  conclusion  the  opposite  of 
that  just  mentioned,  and  adopted  the  opinion 
that  the  phenomena  "  depend  upon  an  influ- 
ence purely  nervous"*  exerted  by  the  fifth  nerve 
upon  the  eye, — "  an  influence  independent  of 
the  connection  of  the  nerve  with  the  spinal  mar- 
row, "f — an  influence  "  proper  to  the  nerve, 

*  Anatomie  des  Systemes  nerveux,  &c.  t.  ii. 
p.  716. 

t  Journal  de  Physiologie,  p.  304. 


which  has  not  its  source  in  the  cerebro-spinal 
system,  and  which  is  even  the  more  energetic, 
the  farther  we  remove  from  that  system  to  a 
certain  distance,"  of  which  the  following  is  his 
proof.  "  Alterations  of  nutrition  in  the  eye  are 
the  less  complete,  the  less  rapid,  as  we  remove 
farther  from  the  point  of  branching  of  the  nerves 
of  the  fifth  pair,  and  as  we  cut,  within  the  cra- 
nium, the  fasciculus  of  origin  the  nearer  to  its 
insertion  ;  finally,  the  section  of  the  nerve  on 
the  margin  of  the  fourth  ventricle  no  longer 
produces  any  alteration  in  the  state  of  the 
eye."  *  In  this  view  there  are  plainly  two  posi- 
tions advanced,  viz.  that  the  nerve  does  itself 
exert  a  proper  and  independent  influence  upon 
the  nutrition  of  the  eye,  and  that  it  is  the  sec- 
tion of  the  nerve  which  causes  the  exercise  of 
that  influence,  or,  to  use  his  own  words,  which 
is  the  cause  of  the  inflammation,  &c.  That 
the  occurrence  of  the  alterations  in  the  eye,  in 
the  case  in  question,  is  not  due  to  an  influence 
exerted  by  the  brain  through  the  nerve,  and 
that  it  must  proceed  from  another  cause,  and 
that  not  dependent  upon  the  connection  be- 
tween them,  is  manifest,  since  it  is  consequent 
upon  the  interruption  of  that  connection  ;  and 
therefore,  if  the  nerve  do  possess  the  supposed 
influence,  it  must  be  a  proper  and  independent 
one  :  but  are  we,  therefore,  to  infer  that  the  nerve 
does  exert  such  an  influence  upon  the  organ  ? 
It  appears  to  the  writer  that  we  cannot :  for  can 
we  suppose  that  the  nerve  is  endowed  with  a 
property  to  be  displayed  expressly  under  cir- 
cumstances, which  it  is  fair  to  say  were  not 
contemplated  in  the  establishment  of  natural 
laws,  viz.  in  cases  of  mutilation?  or  is  it  possi- 
ble that  a  separate  influence  can  exist  in  the 
nerve  and  increase  in  energy  in  proportion  as 
the  nerve  is  curtailed ;  for  the  nearer  the  section 
is  made  to  the  eye,  the  more  remarkable  are 
the  effects  ;  or  if  any  other  proof  that  the  nerve 
does  not  possess  such  an  influence  be  wanting, 
can  we  suppose  that  it  is  possessed  for  the  eye 
and  not  for  the  other  parts  to  which  the  branches 
of  the  nerve  are  distributed  ?  Why  does  not 
inflammation  forthwith  assail  the  nostrils,  the 
mouth,  and  cheeks  upon  the  mere  section  of 
the  nerve,f  as  well  as  the  eye  ?  Manifestly  be- 

*  Op.  cit.  ibid. 

t  It  is  stated  by  Professor  Alison,  Outlines  of 
Physiology,  p.  147,  that  inflammation,  ulceration, 
and  sloughing  are  produced  sometimes  on  the  mem- 
brane of  the  nose  and  on  the  gums  by  section  of  the 
fifth  nerve,  "as  was  first  ascertained  by  Magendie." 
The  only  passages  approaching  at  all  to  this  state- 
ment, which  the  author  has  found  in  Magendie's 
writings,  are  at  page  181,  Journal  de  Physiologie, 
t.  iv,  and  page  717,  Anatomie  des  Systemes  Ner- 
veux, &c.  Desmoulins  et  Magendie,  t.  ii.  In  the 
first  he  says,  "  when  a  single  nerve  is  cut,  there 
appear  alterations  in  the  nostrils,  the  mouth,  the 
surface  of  the  tongue  on  that  side  ;  the  half  of  the 
tongue  becomes  whitish,  its  epidermis  is  thickened, 
the  gums  quit  the  teeth  ;  the  alimentary  matters 
sink  into  the  intervals  which  are  formed  ;  probably 
because  the  animals  having  no  longer  their  atten- 
tion attracted  by  the  sensation  of  the  tendency  of 
the  matters  to  pass  between  the  teeth  and  the 
gums,  push  them  thither  without  perceiving  it;" 
and  in  the  second,  "  a  part  of  the  broken  food  re- 
mains on  that  side,  between  the  teeth  and  the 
cheek,  and  its  contact  terminates  by  ulcerating  the 


FIFTH  PAIR  OF  NERVES. 


311 


cause  no  such  influence  exists ;  and  indeed  the 
data  upon  which  it  has  been  assumed,  instead 
of  proving  the  position,  leave  it  precisely  as  it 
was ;  for  insomuch  as  the  occurrence  of  the 
phenomena  upon  the  section  prove  the  exist- 
ence of  the  influence  of  the  nerve,  in  the  same 
degree  does  the  absence  of  the  phenomena 
upon  the  section  of  the  nerve  disprove  it. 

But  was  the  inflammation  caused  by  the 
section  of  the  nerve?  This  question,  which  cer- 
tainly ought  to  have  been  determined  satisfac- 
torily before  a  theory  had  been  founded  upon 
the  assumption,  appears  to  the  writer  to  have 
been  decided  too  hastily  in  the  affirmative.  If 
the  section  were  the  cause,  no  sufficient  reason 
can  be  assigned  why  it  should  occasion  inflam- 
mation in  one  part,  to  which  the  nerve  is  distri- 
buted, and  not  in  another,  yet  such  is  the  case; 
the  eye  is  the  only  part  in  which  inflammation 
supervenes,  either  so  uniformly  or  so  quickly 
as  to  afford  any  ground  for  attributing  the  pro- 
cess to  the  section.  In  the  second  place,  were 
the  section  the  real  and  essential  cause,  it  can- 
not be  supposed  either  on  the  one  hand  that 
non-essential  circumstances  could  influence,  or 
at  all  events  prevent  the  effect,  or  on  the  other, 
that  they  could  produce  it.  Now  it  will  pre- 
sently appear  that  both  the  one  and  the  other 
may  take  place ;  and  a  comparison  of  Magen- 
die's  experiments  and  their  results  would  alone 
suffice  to  shew  that  the  real  cause  is  to  be 
sought  elsewhere  than  in  the  section  of  the 
nerve.  Magendie  divided  the  nerve  in  three 
different  situations ;  first,  through  the  temporal 
fossa;  secondly,  within  the  cranium,  between 
the  Gasserian  ganglion  and  the  pons  Varolii  ; 
and  thirdly,  at  the  margin  of  the  fourth  ventri- 
cle ;  and  his  own  general  account  of  the  results, 
which  has  been  already  cited,  is  as  follows  : 
*f  those  alterations  in  the  nutrition  of  the  eye  are 
the  less  complete,  the  less  rapid,  as  we  recede 
more  from  the  point  of  branching  of  the  nerves 
of  the  fifth  pair,  and  as  we  cut,  within  the  cra- 
nium, its  fasciculus  of  origin  the  nearer  to  its 
insertion  ;  finally,  the  section  on  the  margin  of 
the  fourth  ventricle  no  longer  produces  any 
alteration."  It  is  plain,  then,  that  the  nerve 
may  be  cut,  and  the  changes  in  the  eye  ensue 
or  not,  according  to  circumstances  to  be  yet 
explained.  On  the  other  hand,  that  effects 
similar  in  kind,  if  not  equal  in  degree,  may  be 
produced  by  circumstances  not  essential  to  their 
production, — according  to  the  doctrine  main- 
tained, but  incidentally  associated  with  the 
supposed  cause, — that  such  effects  may  be  pro- 

buccal  membrane."  In  neither  of  those  extracts  is 
there  mention  of  inflammation  or  sloughing  ;  and 
the  ulceration  which  is  mentioned,  is  attributed  to 
another  cause  than  the  section  of  the  nerve.  On 
the  other  hand,  the  writer  has  frequently  divided 
the  lingual  branches  of  the  fifth  nerve  and  pre- 
served the  animals  for  months  afterward,  and  he 
has  been  unable  to  detect  any  change  in  the  condi- 
tion of  the  tongue,  except  this,  that  in  some  the  tip 
of  the  organ,  from  being  allowed  to  remain  between 
the  teeth,  and  thus  to  be  exposed  to  injury,  ulce- 
rated, and  this  continued  until  the  tip  was  re- 
moved, when  the  extremity  of  the  organ  healed, 
and  it  appeared  to  be  in  all  other  respects  as 
before. 


duced  by  such  circumstances,  when  dissociated 
from  the  other  and  operating  separately,  the 
author  feels  justified  in  asserting,  from  the  re- 
sult of  some  experiments  lately  made  by  him- 
self, which  lead  to  the  conclusion  that  similar 
effects  may  be  produced  without  the  section  of 
the  nerve  at  all,  and  that  an  injury  in  the  vici- 
nity of  the  orbit  may  excite  them  though  nei- 
ther the  trunk  of  the  fifth  itself,  nor  its  ophthal- 
mic division  have  been  divided.  In  an  endea- 
vour to  determine  the  nerves  of  taste,  he  under- 
took the  removal  of  the  ganglion  of  Meckel 
from  the  dog ;  in  order  to  accomplish  this  it  was 
necessary  to  displace  the  zygoma  and  the  coro- 
noid  process  of  the  jaw ;  he  attempted  it  seve- 
ral times  before  he  succeeded,  and  failed  at 
different  stages  of  the  operation  ;  but  in  almost 
every  instance  the  eye  of  the  same  side  became 
bleared  within  the  next  two  days.  The  animal 
kept  it  nearly  closed :  a  whitish  puriform  mat- 
ter was  discharged  from  it,  in  quantity  propor- 
tioned to  the  case,  which  concreted  between 
the  lids ;  and  the  animal  made  no  attempt  to 
remove  the  matter  or  cleanse  the  eye :  the  affec- 
tion of  the  eye  was  always  proportioned  to  the 
violence  done,  and  abated  with  the  inflamma- 
tion of  the  wound  ;  and  in  one  of  the  instances 
in  which  the  ganglion  was  removed,  it  actually 
produced  opacity  of  the  cornea,  and  ulceration 
in  that  structure,  which  continued  after  the 
lapse  of  more  than  a  month  from  the  operation ; 
yet  most  assuredly  neither  infra-orbital  nor 
ophthalmic  nerves  had  been  divided.  Thus, 
if,  on  the  one  hand,  the  nerve  may  be  cut  and 
the  changes  not  ensue,  on  the  other  it  may  be 
left  uncut,  and  the  changes  may  occur. 

It  may  be  objected  that  the  effects  here  de- 
scribed fall  very  far  short  of  those  which  took 
place  in  the  experiments  of  Magendie.  That 
they  fall  short  of  those  which  occurred  on  the 
division  of  the  nerve  in  the  temporal  fossa  is 
quite  true,  but  it  is  equally  so  that  they  far  ex- 
ceed those  consequent  upon  the  section  at  the 
margin  of  the  fourth  ventricle.  The  objection, 
therefore,  would  be  devoid  of  weight,  and  if 
we  suppose  superadded  to  the  violence  already 
done  when  the  nerves  are  not  divided,  the  ad- 
ditional violence  necessarily  inflicted  in  the 
division  of  them,  we  shall  have  a  ready  expla- 
nation furnished  of  the  higher  degree  to  which 
the  effects  produced  amount  in  one  case  than 
in  the  other. 

From  the  preceding  considerations  it  appears 
to  the  author  necessary  to  infer, that  the  changes 
which  supervene  in  the  eye  after  the  section  of 
the  fifth  nerve  in  certain  cases,  take  place  inde- 
pendently of  the  section,  as  the  primary,  imme- 
diate, or  proper  cause ;  for  were  it  otherwise, 
it  cannot  be  supposed  either  that  the  difference 
of  half  an  inch  to  one  side  or  the  other,  as  re- 
gards the  point  of  section,  could  so  influence  the 
cause  as  to  prevent  or  allow  these  changes,  or 
that  they  could  occur,  even  in  degree,  without  it. 

How,  then,  are  the  phenomena  to  be  ex- 
plained? It  has  been  said  by  Magendie  that 
they  are  less  marked  the  more  we  recede  from 
the  point  of  branching  of  the  nerve;  but  it  is 
to  be  further  observed,  that,  as  we  recede  from 
the  point  of  branching  of  the  nerve,  we  recede 


312 


FIFTH  PAIR  OF  NERVES. 


also  from  the  orbit,  the  eye  and  its  appendages, 
and  in  our  operation  for  the  division  of  the 
nerve  we  do  less  violence  either  in  their  vicinity 
or  actually  to  them,  until  the  operation  is  per- 
formed at  such  a  distance  from  those  parts, 
that  they  are  not  involved  in  the  injury  inflicted. 
Thus  the  nerve  cannot  be  divided  through  the 
temporal  fossa  without  great  violence  done  to 
the  parts  in  the  vicinity  of  the  orbit,  and  con- 
nected with  the  eye  as  well  as  the  fifth  nerve, 
as  is  evident  from  the  result,  and  as  has  been 
explained  elsewhere.*  In  the  section  be- 
tween the  ganglion  and  the  pons,  the  violence 
is  inflicted  at  a  part  more  remote  than  the 
former,  from  the  orbit,  &c,  and  here,  according 
to  his  own  account,  the  effect  upon  the  eye 
was  much  less  considerable.  But  the  most  re- 
markable fact  is,  that  the  alterations  of  nutrition 
are  much  less  marked  than  in  the  former  mode 
of  experiment ;  there  forms  only  a  partial  in- 
flammation at  the  superior  part  of  the  eye,  and 
the  opacity  which  ensues  occupies  but  a  small 
segment  upon  the  circumference  of  the  cornea 
at  the  superior  part ;  and  in  the  third  case  the 
parts  injured  are  so  far  removed  from  the  eye, — 
(in  dividing  the  nerve  on  the  margin  of  the 
fourth  ventricle,  Magendie  exposed  the  parts  by 
"  opening  the  spinal  envelopes  between  the 
occiput  and  the  first  vertebra,") — that  the  effects 
of  the  injury  could  not,  under  ordinary  circum- 
stances, extend  to  it,  and  accordingly  in  it  no 
alteration  occurred.  It  would  seem,  then,  that 
the  great  violencef  inflicted,  either  in  the  vici- 
nity of  the  eye  or  actually  to  its  appendages, 
constitutes  the  primary  and  immediate  cause  of 
the  alterations  which  took  place  in  the  eye  in 
the  experiments  under  consideration.  But  it  is 
likely  they  were  the  result  of  more  causes  than 
one,  for  there  were  also  engaged  in  the  experi- 
ments other  agencies,  the  influence  of  which 
must  have  enhanced  greatly  that  of  the  violence 
inflicted  by  the  operation;  thus,  in  the  first 
place,  in  some  of  the  instances  at  least, — and 
we  have  no  evidence  that  it  was  not  so  in  all, — ■ 

*  It  is  hardly  possible  to  conceive  the  section 
effected  at  the  point  and  in  the  mode  adopted, 
without  a  division  of  most  of  the  nerves  and  vessels 
supplying  the  eye  and  its  appendages. 

t  A  better  idea  of  the  injury  likely  to  be  inflicted 
in  the  experiment  will  be  formed  from  a  brief  ac- 
count of  the  mode  of  conducting  it.  A  lancet- 
pointed  style  is  driven  into  tlie  cranium  through 
the  temporal  fossa  and  through  its  base,  and  when 
carried  in  to  such  depth  as  the  experience  of  the 
operator  teaches  him  to  be  sufficient,  its  point  is 
moved  upward  and  downward,  until  the  loss  of  sensa- 
tion in  the  superficial  paits  assures  him  thatthe  fifth 
nerve  has  been  divided.  After  such  a  proceeding  the 
question  should  rather  be,  what  mischief  has  not 
been  done  than  what  has.  There  cannot  be  any 
assurance  that,  in  the  division  of  the  fifth,  the  third, 
fourth,  and  sixth  nerves  with  the  branches  of  the 
sympathetic — nay,  the  optic  itself — have  not  been 
involved  :  and  if  to  this  be  added  the  almost  cer- 
tainty of  dividing  the  internal  carotid  artery,  from 
which  the  supply  of  blood  to  the  internal  structures 
of  the  eye  is  directly  derived,  and  the  division  of 
which  causes  the  death  of  the  greater  number  of 
the  subjects  of  experiment,  an  amount  of  injury 
will  be  made  out,  quite  adequate  to  account  for  the 
total  loss  of  the  eye,  and  which  must  reduce  the 
influence  of  the  fifth  in  producing  it  to  a  low  degree 
indeed. 


a  highly  irritating  agent  was  introduced,  and, 
in  consequence  of  the  insensibility  of  the  organ, 
probably  in  considerable  quantity,  into  the  eye; 
and  in  the  second  the  eye  was  left  under  cir- 
cumstances more  than  enough  to  excite  inflam- 
mation and  to  produce  serious  injury  to  it, 
though  the  organ  had  remained  in  full  posses- 
sion of  all  those  safeguards  with  which  its  sen- 
sibility and  the  sympathetic  action  established 
thereby  between  its  several  protecting  appen- 
dages naturally  endow  it ;  for  "  the  eye  was 
dry;"  and  "  the  eyelids  were  either  widely 
open  and  immoveable,  or  else  they  were  glued 
together  by  the  puriform  matters,  which  were 
dried  between  their  margins ;"  and  an  organ  so 
circumstanced  has  abundant  cause  for  inflamma- 
tion, independently  either  of  nervous  influence 
or  of  its  absence.  It  may  be  said  that  Magen- 
die has  proved  that  neither  the  open  state  of 
the  eyelids  nor  the  want  of  the  lachrymal  secre- 
tion is  adequate  to  the  effect.  Admitting  for  a 
moment  that  he  has,  he  certainly  has  not  shewn 
that  the  combined  influence  of  the  two  is  inad- 
equate to  produce  it ;  but  the  first  position  is 
by  no  means  satisfactorily  established :  his 
mode  of  determining  the  question,  whether  the 
inflammation  was  excited  by  the  eye  remaining 
constantly  open  or  not,  was  by  the  division  of 
the  portio  dura,  and  his  experiment  has  certainly 
proved  that  the  effect  of  the  section  of  that 
nerve  will  not  excite  inflammation  in  the  eye, 
but  no  more ;  inasmuch  as  such  section  does 
not  produce  a  permanently  open  state  of  the 
eye  :  an  eye  so  circumstanced  will  be  closed 
during  sleep,  and  even  during  the  waking  state 
it  requires  attention  and  experience  in  such 
observations  to  discover  that  the  animal  has 
lost  the  power  of  closing  the  lids  by  a  muscular 
effort  of  those  parts  themselves  ;  for  by  the  sud- 
den exertion  of  the  power  of  retracting  the  eye, 
which  inferior  animals  possess  to  a  remarkable 
degree,  the  lids  become  nearly,  if  not  quite, 
closed,  and  the  animal  appears  to  wink  as  well 
as  before,  while  by  rolling  the  eye  the  different 
parts  of  its  surface  are  in  turn  brought  beneath 
the  lids,  and  thus  no  one  part  is  ever  left  long 
absolutely  uncovered.  So  great  indeed  is  the 
power  which  brutes  possess  in  this  respect,  that 
the  author  has  seen  a  dog  in  which  the  portio 
dura  had  been  divided  on  one  side,  presented 
for  observation,  and  persons  aware  that  the 
nerve  had  been  divided,  yet  not  able  to  disco- 
ver on  which  side  it  had  been  done,  and  even 
deny  that  the  lids  were  paralyzed  on  either  side, 
until  something  was  approximated  to  each  eye 
successively,  when  the  uninjured  eye  was  at 
once  closed,  but  the  other  remained  open,  and 
the  animal  appeared  looking  at  the  object, 
which  it  was  unable  to  exclude.  It  is  obvious, 
then,  that  the  question  has  not  been  and  cannot 
be  determined  in  this  way. 

To  the  causes  already  enumerated  must  be 
added  the  loss  of  the  nervous  influence,  for  it 
is  not  intended,  in  what  has  preceded,  to  assert 
that  the  section  of  the  fifth  has  no  share  in  the 
production  of  the  changes  in  the  eye,  but  only 
that  it  is  not  the  primary  or  essential  cause  of 
them.  Indirectly  it  must  contribute  powerfully 
to  produce  and  aggravate,  or  it  may  even  excite 


FIFTH  PAIR  OF  NERVES. 


313 


them  ;  for  by  destroying  the  sensation  of  the 
organ,  it  must  leave  it  exposed  to  the  unin- 
terrupted influence  of  many  irritating  agents, 
which  naturally  would  excite  inflammation, 
were  it  not  that  we  are  warned  through  the 
sensibility  of  the  organ  to  avoid  or  to  remove 
them,  but  in  every  such  case  they  are  the  im- 
mediate, and  the  insensibility  only  the  mediate 
cause  of  the  effects  produced,  and  such,  it  ap- 
pears to  the  author,  is  the  part  played  by  the 
section  of  the  fifth  in  giving  rise  to  inflamma- 
tion in  the  eye.  It  is  further  to  be  observed 
that  the  occurrence  of  inflammation  in  the 
eye  in  cases  in  which  the  influence  of  the  fifth 
nerve  upon  it  had  been  lost,  had  been  noticed 
and  given  to  the  public  by  Bell  prior  to  the 
publication  of  it  by  Magendie.  In  the  Philo- 
sophical Transactions  for  1823,  (Magendie's 
memoir  dates  1824,)  Sir  C.  Bell  reports  the 
case  of  a  patient  under  the  care  of  his  colleague 
Dr.  Macmichael,  in  which  the  surface  of  the 
eye  was  totally  insensible,  and  the  eye  re- 
mained fixed  and  directed  straightforward, 
while  the  vision  was  entire.  "  The  outward 
apparatus  being  without  sensibility  and  mo- 
tion, and  the  surface  not  cleared  of  irritating 
particles,  inflammation  has  taken  place,  and 
the  cornea  is  becoming  opaque ;  thus  proving 
the  necessity  of  the  motions  of  the  eye  to  the 
preservation  of  the  organ."  And  in  the  same 
volume  he  reports  also  a  case  from  the  expe- 
rience of  Mr.  Crampton  of  Dublin,  bearing 
strongly  upon  the  question,  because  it  shews 
satisfactorily  that  the  sensation  of  the  organ, 
and  consequently  the  influence  of  the  nerve, 
may  be  obliterated,  and  inflammation  not 
ensue  until  a  stimulus  have  been  applied, 
though  the  conjunctiva  manifestly  retained  its 
susceptibility  to  the  impression  of  that  sti- 
mulus. Mr.  Crampton's  account  of  the  case 
is  as  follows:  "  When  she  told  me  her  eye  was 
dead,  as  she  expressed  it,  to  be  certain  I  drew 
my  finger  over  its  surface,  and  so  far  was  this 
from  giving  her  pain,  that  she  assured  me  she 
could  not  feel  that  I  was  touching  it  at  all.  The 
eyelids  made  no  effort  to  close,  while  I  was 
doing  this;  but  the  conjunctiva  appeared  sen- 
sible to  the  stimulus,  as  a  number  of  vessels  on 
the  surface  of  the  eye  became  immediately  in- 
jected with  blood." 

Another  circumstance  may  be  advanced  in  fa- 
vour of  the  opinion  that  the  nerve  influences  the 
nutrition  of  the  parts,  to  which  it  is  necessary  to 
allude,  viz.  the  wasting  of  the  muscles  of  masti- 
cation in  cases  of  the  loss  of  the  nerve's  influence. 
This  fact  may  be  otherwise  explained  ;  the  de- 
velopment of  muscles  is  always  influenced  by 
their  exercise,  which  being  lost  they  waste,  and 
it  is  neutralized  by  the  counter-fact  that,  though 
these  masticatory  muscles  waste,  the  muscles 
of  the  face  and  its  other  structures  do  not.  In 
fine  there  appears  to  the  writer  to  be  no  good 
reason  for  attributing  to  the  fifth  nerve  a  direct 
influence  upon  the  nutrition  of  the  structures 
to  which  it  is  distributed;  the  existence  of  such 
an  influence  would  be  incompatible  with  the 
simplicity  of  natural  laws,  for  in  such  case 
there  must  be  two  such  influences  in  existence, 
one  in  the  nerve  directing  the  nutrition  of  the 


parts  with  which  it  is  connected,  and  anothe 
elsewhere  to  direct  that  of  the  nerve. 

Magendie  confirms  his  view  of  the  influence 
exerted  by  the  fifth  nerve  upon  the  functions 
and  nutrition  of  the  eye,  by  reference  to  a  case 
published  by  Serres  in  the  fifth  volume  of  the 
Journal  of  Physiology,  which  "  presented  all 
the  phenomena  attending  section  of  the  fifth 
pair,"  and  in  which  there  existed  complete 
alteration  of  the  trunk  of  the  nerve  in  its  sen- 
sible portion ;  "  followed  by  loss  of  sight,  of 
smell,  of  hearing,  and  of  taste  on  the  same 
side."  Before  detailing  this  case,  the  writer 
cannot  refra:n  from  observing  that  in  such 
cases  none  but  unquestionable  evidence  can  be 
admitted  if  we  would  arrive  at  a  certain  and 
unquestionable  conclusion.  Whether  the  case 
of  Series  be  such,  it  rests  with  the  reader  to 
decide;  and  first,  what  was  the  condition  of 
the  patient  in  other  respects  ?  Serres  replies  : 
"  His  air  was  dull;  his  physiognomy  gave,  at 
first  sight,  the  idea  of  imbecility;  he  seemed 
to  conceive  slowly  and  to  comprehend  with 
difficulty,  the  questions  which  were  put  to 
him.  When  he  wished  to  reply,  it  was  evi- 
dent that  he  experienced  difficulty  in  express- 
ing himself;  he  pronounced  with  difficulty, 
and  the  little  that  he  said  seemed  to  require, 
on  his  part,  a  considerable  effort :  his  cranium 
was  voluminous  compared  to  the  rest  of  his 
body ;  some  pupils  suspecting  a  commencing 
hydrocephalus,  thought  that  they  observed  a 
separation  between  the  parietal  and  temporal 
bones,  but  the  prominence  of  the  eyes  made 
me  reject  that  conjecture ;  the  maxillary  and 
malar  bones  were  a  little  separated,  which 
had  produced  a  flattening  of  the  nose ;  the  pa- 
tient had  some  difficulty  in  moving  the  tongue; 
the  motions  and  sensibility  of  the  limbs  were 
not  affected,  only  he  moved  the  lower  extre- 
mities less  freely  than  the  upper ;  he  had  been 
for  some  time  subject  to  epilepsy;  he  had  a 
sister  deaf  and  dumb."  A  case  so  complicated 
as  this,  in  which  there  manifestly  existed  ex- 
tended disease  of  the  encephalon,  must  be 
rejected  as  altogether  inconclusive.  But  to 
proceed,  the  patient  was  admitted  into  hospital 
in  September  1823:  at  his  admission  he  had  a 
chronic  ophthalmia  of  his  right  eye,  which  was 
considered  scrofulous.  In  the  course  of  De- 
cember he  was  attacked  by  an  acute  ophthalmia 
of  the  same  eye,  attended  by  adema  of  the  lids, 
and  commencing  opacity  of  the  cornea;  the 
ophthalmia  was  dispersed  after  ten  or  twelve 
days;  but  the  cornea  was  rendered  altogether 
opaque  throughout  its  whole  extent;  of  course 
the  loss  of  vision  on  that  side  was  the  neces- 
sary result.  In  the  course  of  January  1824  it 
was  observed  that  the  right  eye  was  insensible, 
and  soon  after  that  the  eyelid  and  nostril  of  the 
same  side  were  also  insensible,  and  likewise 
the  tongue  on  that  side,  while  all  was  natural 
on  the  other;  soon  after  the  gums  inflamed 
upon  the  right;  they  were  red,  some  white 
places  existed  here  and  there,  they  were  swollen 
at  the  circumference  of  the  sockets;  the  tongue 
moved  always  with  difficulty;  the  hearing  was 
not  then  affected;  in  July  the  affection  of  the 
gums  extended  to  the  left  side,  but  the  right 


314 


FIFTH  PAIR  OF  NERVES. 


was  always  more  affected  than  the  left.  During 
August  the  gums  became  separated  on  the 
right  from  the  necks  of  the  teeth ;  there  existed 
between  the  latter  and  the  gums  spaces  into 
which  tartar  and  portions  of  food  had  pene- 
trated ;  the  patient  suffered  from  the  epileptic 
paroxysms  with  variable  degrees  of  severity  : 
he  next  fell  into  a  general  cachexy,  with  extreme 
debility,  impeded  respiration,  small  frequent 
pulse,  great  alteration  of  countenance,  and  un- 
usual taciturnity.  It  is  stated  that  in  August 
he  acknowledged  deafness  on  the  right,  which 
diminished  and  again  increased;  the  sensibility 
was  perfectly  preserved  in  all  the  extent  of  the 
right  side  of  the  face  ;  the  patient  died  on  the 
12th  of  August.  Both  the  brain  and  the  fifth 
nerve  were  found  after  death  much  diseased, 
the  brain  on  the  left  and  the  nerve  on  the  right 
side. 

The  details  of  the  case  have  been  given  more 
at  length  than  may  perhaps  seem  necessary,  but 
the  question  is  interesting,  and  as  the  bearing 
of  the  case  upon  it  could  not  be  determined 
otherwise,  the  writer  has  endeavoured  to 
give  them  faithfully.  The  difficulty  of  obtain- 
ing precise  knowledge  from  so  complicated  a 
case  has  been  already  adverted  to.  We  come 
next  to  inquire  how  far  it  substantiates  the 
writer's  views,  or  how  far  it  can  be  considered 
to  establish  the  opinion  of  Magendie.  Serres, 
as  has  been  already  stated,  announces  it  as  an 
instance  of  disease  of  the  fifth  nerve  followed 
by  loss  of  smell,  sight,  hearing,  &c.  Surely 
the  loss  of  these  several  functions,  thus  an- 
nounced, should  have  been  satisfactorily  esta- 
blished, before  asserted ;  but  such  does  not 
appear  to  have  been  the  case.  For  the  first, 
notwithstanding  the  announcement,  we  find 
Serres  himself,  after  the  patient's  death,  ac- 
knowledging, "  toutefois  l'odorat  n'avait  pas 
completement  disparu,  puisque,"*  &c.  The 
sense  of  smell  then  plainly  was  not  lost.  In 
the  next  place  there  was  loss  of  vision,  but 
from  what  cause  ?  from  opacity  of  the  cornea, 
and,  so  far  as  we  have  data  for  forming  a 
judgment,  from  it  alone.  We  have  no  reason 
to  think  that  any  alteration  had  been  pro- 
duced in  the  power  of  the  eye  to  receive 
sensations  of  light,  any  disturbance  in  the 
function  of  the  retina,  or  any  other  change 
than  the  occurrence  of  a  physical  impediment 
to  the  exercise  of  a  function,  which  the  organ 
may  have  retained  in  full  vigour,  had  it  only 
been  allowed  to  exert  it:  the  evidence,  there- 
fore, afforded  by  the  case,  is  too  imperfect  to 
be  of  value. 

Let  us  next  inquire  how  far  it  bears  out  the 
opinion  that  the  fifth  nerve  possesses  a  proper 
and  direct  influence  upon  the  nutrition  of  the 
eye :  here  we  shall  find  ourselves  equally  at 
fault  for  the  resemblance  which  it  has  been 
sought  to  establish.  In  Magendie's  experi- 
ments the  section  of  the  nerve  preceded  the 
occurrence  of  the  phenomena,  and  it  is  reason- 
able to  expect,  that,  here,  the  loss  of  sensibi- 
lity, which  we  are  to  regard  as  the  analogue 
of  the  section,  should  have  preceded  the  oc- 

1  Journ.  de  Phys.  t.  v.  p.  245. 


currence  of  the  inflammation  of  the  eye ;  but 
no.  The  patient  had  a  chronic  ophthalmia,  con- 
sidered scrofulous  at  the  time  of  his  admission; 
(he  was  admitted  in  September,  and  in  De- 
cember he  was  attacked  by  acute  ophthalmia, 
attended  by  oedema  of  the  lids ;  a  circumstance 
not  noticed  in  any  of  Magendie's  experiments;) 
the  inflammation  was  dispersed,  and  in  the 
course  of  January,  and  not  till  then,  (i.  e.  four 
months  after  his  admission  and  about  one  after 
the  occurrence  of  the  second  inflammation,) 
the  insensibility  of  the  eye  was  for  the  first 
time  observed.  Surely  we  have  no  reasonable 
grounds  here  for  attributing  the  inflammation 
of  the  eye  and  the  opacity  of  the  cornea  to  the 
disease  of  the  nerve,  or  for  supposing  that  there 
existed  any  connexion,  in  the  relation  of  cause 
and  effect,  between  them.  If  we  seek  for  a 
resemblance  in  other  points,  we  shall  be  equally 
disappointed.  It  has  been  already  remarked 
that  oedema  of  the  eyelids,  which  occurred  in 
this  case,  is  not  one  of  the  phenomena  of 
Magendie's  experiments.  Again,  the  affection 
of  the  gums  related  is  altogether  unlike :  in 
Serres'  case  they  are  stated  to  have  become 
inflamed,  and  to  have  been  affected  on  both 
sides,  only  more  on  the  right  than  on  the  left; 
in  Magendie's  it  is  simply  stated  that  they 
separated  from  the  teeth  and  only  on  the  side 
on  which  the  nerve  had  been  divided  ;  and, 
lastly,  the  continuance  of  sensibility  upon  the 
right  side  of  the  face  throughout  casts  an  im- 
pervious obscurity  over  the  entire. 

Besides  those  effects  of  the  section  of  the 
trunk  of  the  nerve  which  have  been  discus- 
sed, there  are  others,  for  which  we  are  in- 
debted also  to  Magendie,  and  which  deserve 
notice. 

lie  found  after  the  section  of  the  nerve  that 
the  eye  was  dry,  and  the  motion  of  winking 
had  ceased  ;  the  globe  of  the  eye  itself  seemed 
to  have  lost  all  its  motions ;  the  iris  was 
strongly  contracted  and  immoveable.  The  loss 
of  sensibility  in  the  conjunctiva,  and  the  sus- 
pension of  the  secretion  of  the  tears,  he  refers 
to  the  loss  of  the  influence  of  the  fifth  nerve 
upon  the  former  part  and  upon  the  lachrymal 
gland  :  the  explanation  of  the  first  is  in  accor- 
dance with  the  previously  established  proper- 
ties of  the  nerve  as  already  ascertained  by  Mayo, 
but  it  is  not  equally  so  that  the  secretion  of 
the  lachrymal  gland  is  directly  controlled  by 
the  same  influence,  and  it  remains  to  be  deter- 
mined whether  the  effect  in  this  case  was  not 
an  indirect  one,  consequent  upon  the  previous 
insensibility  of  the  conjunctiva.  The  other  re- 
sults of  the  section — the  immobility  of  the 
eyelids,  that  of  the  eye,  and  the  permanent 
contraction  of  the  pupil — he  has  not  satisfac- 
torily explained :  the  immobility  of  the  lids 
may,  it  appears  to  the  author,  be  attributed 
with  much  probability  to  the  insensibility  of 
the  conjunctiva  or  of  the  internal  structures  of 
the  eye,  and  seems  a  likely  consequence  there- 
of :  the  ordinary  action  of  winking  would  seem 
to  be  called  into  play  through  the  sensations  of 
those  structures,  and  the  cessation  of  that 
action  upon  the  loss  of  their  sensibility  is  as 
natural  an  effect  as  the  immobility  of  the  lips 


FIFTH  PAIR  OF  NERVES. 


315 


on  the  contact  of  food  consequent  upon  the 
division  of  the  infra-orbital  and  inferior  maxil- 
lary nerves  :  and  this  view  derives  confirmation 
from  the  circumstance  that  in  the  instance 
under  consideration  the  immobility  of  the  lids 
is  not  the  consequence  of  paralysis,  for  on  the 
sudden  admission  of  solar  light  into  the  eye, 
the  action  of  the  muscle  was  excited,  and  the 
eyelids  were  closed.  The  immobility  of  the 
eye  itself  the  author  cannot  but  regard  as  an 
incidental  circumstance,  caused  by  the  com- 
plication to  which  Magendie  himself  refers, 
viz.  the  division  of  the  motor  nerves  of  the 
eye  along  with  the  fifth,  and  this  explanation 
is  rendered  more  likely,  if  not  confirmed,  by 
the  effect  of  the  section  when  made  between 
the  ganglion  and  the  brain,  in  which  case  the 
motor  nerves  are  not  involved,  nor  the  motion 
of  the  eye  affected.  It  is  to  be  regretted  that 
Magendie  has  not  given  a  report  of  a  dissec- 
tion after  death  of  some  of  the  animals  upon 
which  the  former  experiment  had  been  per- 
formed, by  which  the  question  might  have 
been  determined.  The  permanent  contraction 
of  the  iris  is  an  extraordinary  and  as  yet  unex- 
plained effect :  it  occurred  only  when  the 
experiment  was  made  upon  rabbits,  and  is 
at  variance  with  the  results  of  similar  experi- 
ments upon  other  animals,  performed  both  by 
Mayo  and  by  Magendie  himself.  In  Mayo's* 
experiments,  which  were  done  upon  pigeons, 
in  no  instance  was  contraction  of  the  pupil 
caused  by  division  of  the  nerves  connected 
with  the  eye  or  its  appendages.  When  the 
optic  nerve  was  divided,  the  pupil  became  fully 
dilated.  When  the  third  nerve  was  divided, 
the  same  result  ensued  ;  and  when  the  fifth 
was  divided,  the  iris  contracted  as  usual  on  the 
admission  of  light;  in  Magendie's  experiments 
again  upon  cats  and  dogs  the  pupil  was  en- 
larged.f  The  fact  is,  however,  confirmed  by 
Mayo,  who  found  that  when  the  fifth  nerve 
was  compressed  in  a  rabbit  after  death,  the 
pupil  became  contracted  slowly  and  gradually, 
and  then  slowly  dilated  ;  and  when  the  nerve 
was  divided,  the  pupil  became  contracted  to 
the  utmost,  and  remained  so.  A  correspond- 
ing difference  between  the  conditions  of  the 
pupil  after  death  in  the  subjects  of  experi- 
ment has  been  observed  by  Mayo,  according 
to  whom  in  the  pigeon  and  cat  it  is  naturally 
dilated,  but  in  the  rabbit,  on  the  contrary, 
contracted.^: 

It  has  been  already  stated  that  Magendie 
divided  the  nerve  within  the  cranium  both 
after  and  before  the  occurrence  of  the  ganglion  : 
in  the  latter  case — when  the  section  is  made 
between  the  ganglion  and  the  brain — the  re- 
sults are  different  in  some  remarkable  respects 
from  those  attending  the  section  in  the  former: 
the  effect  upon  the  senses  is  equally  marked  ; 
but  the  motions  of  the  globe  of  the  eye  are 
preserved  almost  always,  from  which  the  author 
would  infer  that  the  loss  of  those  motions  in 
the  former  must  have  been  caused  by  the  divi- 

*  Comment,  part  ii,  p.  4,  5. 
t  Journal,  t.  iv.  p.  309. 
t  Physiology. 


sion  of  the  motor  nerves  along  with  the  fifth, 
by  the  side  of  the  cavernous  sinus  ;  and  also 
the  changes  which  occur  in  the  tissues  of  the 
eye  are  much  less  considerable  ;  the  inflamma- 
tion and  opacity  ensue,  but  not  to  the  same 
extent. 

Another  very  remarkable  result  of  the  sec- 
tion is  displayed  in  the  animal's  mode  of  pro- 
gression as  related  by  Magendie  :  "  when  the 
two  nerves  are  cut  upon  an  animal  it  seems 
blind,  and  its  mode  of  progression  is  most  sin- 
gular ;  it  advances  only  with  the  chin  leant 
strongly  upon  the  ground,  pushing  thus  its 
head  before  it,  and  using  it  as  a  guide  as  the 
blind  does  his  staff :  the  progression  of  an 
animal  in  this  state  differs  altogether  from  that 
of  an  animal  simply  deprived  of  sight ;  the 
latter  guides  itself  easily  by  means  of  its 
whiskers,  and  by  the  sensibility  of  the  skin  of 
its  face  ;  it  stops  at  hollows,  feels  obstacles, 
and,  in  fine,  it  would  be  difficult  to  know 
whether  it  is  blind  or  not;  while  the  animal 
whose  fifth  nerves  have  been  cut  has  but  one 
mode  of  moving,  and  instead  of  avoiding 
obstacles,  it  persists  often  in  pushing  against 
them  for  several  hours,  so  as  finally  to  exco- 
riate the  skin  of  the  anterior  part  of  the 
head."* 

This  account,  which  is  well  calculated  to 
excite  at  first  extreme  surprise,  is  after  all 
strictly  consistent,  and  illustrates  strongly  the 
importance  of  the  nerves  in  question  :  in  fact 
to  the  animal  so  circumstanced  the  head  and 
face  must  be  as  a  part  which  it  does  not  possess, 
or  rather  of  which  it  has  been  suddenly  deprived, 
and  which  it  yet  believes  itself  to  retain  ;  it  can 
have  no  consciousness  of  their  existence,  while 
from  habit,  memory,  and  ignorance  of  the  real 
condition  of  the  parts,  it  yet  believes  them  to 
be  present,  and  to  exercise  all  their  usual  func- 
tions. Thus  the  human  being  whose  limb  has 
been  removed  without  any  knowledge  of  what 
has  actually  occurred  believes  that  he  still  pos- 
sesses it,  acts  as  if  he  did,  and  is  only  con- 
vinced of  his  loss  by  the  evidence  of  the  senses 
of  sight  and  touch.  In  like  manner  the  ani- 
mal acts  under  the  impression  that  it  still 
possesses  its  ordinary  faculties,  and  being 
altogether  unconscious  of  the  contact  of  ob- 
stacles in  consequence  of  its  loss  of  sensation  in 
the  part  which  encounters  them,  it  acts  as  if  it 
were  not  in  contact  with  them,  and  endeavours 
still  to  advance,  while  it  is  unable  to  make 
use  of  sight,  if  this  faculty  be  retained,  as  a 
a  guide,  because  it  has  lost  the  correcting  and 
regulating  assistance  of  the  sensation  of  its 
face  as  exercised  through  its  whiskers ;  and 
hence  it  does  not  appear  to  the  author  that  the 
apparent  blindness  of  the  animal  proves  real 
blindness.  Unassisted  sight  cannot  teach  us 
the  distance  of  objects  ;  and  the  animal  sud- 
denly deprived  of  the  faculty  of  sensation  may 
see  the  object,  but  not  being  made  aware  of  its 
contact,  must  suppose  that  it  has  not  reached 
it,  inasmuch  as  the  usual  notice  of  its  presence 
is  not  given  by  the  sensibility  of  the  face. 

Lastly,  when  the  nerves  have  been  divided 

*  Journ.  de  Phys.  t.  iv.  p.  181. 


316 


FCETUS. 


upon  both  sides,  the  lower  jaw  ceases  to  be 
supported  by  its  muscles,  and  falls.* 

Influence  of  disease  on  the  junctions  of  the 
nerve. — The  inferences  drawn  from  the  anatomy 
of  the  nerve  and  from  physiological  experiment 
conjointly  have  been  confirmed  in  a  remarkable 
manner  by  the  effect  of  disease  of  the  nerve 
upon  the  functions  of  the  parts  to  which  it  is 
distributed:  several  instances  have  been  pub- 
lished exemplifying  either  partially  or  com- 
pletely that  effect,  when,  whether  from  disease 
of  the  trunk  of  the  nerve  itself  or  from  pressure 
upon  it,  its  office  has  been  interrupted,  all  the 
parts  supplied  by  it  are  deprived  altogether  of 
both  their  tactile  and  ordinary  sensibility :  this 
loss  of  sensibility  extends  to  the  whole  of  the 
corresponding  side  of  the  head  so  far  as  the 
distribution  of  the  nerve  reaches  to  the  fore- 
head, temple,  ear,  surface  of  the  eye  and  its 
appendages,  cheek,  nostril  externally  and  inter- 
nally, lower  part  of  the  face,  lips,  and  mouth, 
the  corresponding  half  of  the  tongue,  of  the 
palate,  and  the  fauces  ;  upon  all  these  parts  the 
roughest  contact  produces  no  perceptible  im- 
pression ;  inflammation  is  not  attended  by 
pain,  the  most  pungent  or  irritating  effluvia  do 
not  affect  the  nostril  or  the  conjunctiva,  and 
the  sense  of  taste  is  altogether  lost  in  the  aute- 
rior  part  of  the  same  side  of  the  tongue  :  at  the 
same  time  the  muscles  of  mastication — the  ex- 
ternal ones  at  least — lose  their  contractile  power, 
remain  inactive  during  the  process  and  waste, 
whence  are  produced  a  flattening  and  depres- 
sion in  the  site  of  the  temporal  and  masseter, 
with  prominence  of  the  adjoining  points  of 
bone  :  however  the  special  senses  continue  un- 
affected apparently,  unless  in  so  far  as  the  sense 
of  contact  may  be  necessary  to  the  perfect  or 
ordinary  fulfilment  of  their  function,  the  olfac- 
tory function  seems  much  impaired  ;  the  pa- 
tient is  insensible  to  the  impression  of  ammo- 
nia, snuff,  or  other  pungent  agent,  but  still  ac- 
knowledges a  perception  of  odour.  Vision 
continues  throughout,  and  appears  unaf- 
fected, unless  from  the  supervention  of  in- 
flammation, by  which  the  eye  may  be  spoiled, 
or  from  the  extension  of  the  disease  to  the  optic 
nerve  or  the  brain :  in  the  case  before  alluded 
to,  which  the  author  has  witnessed,  vision  re- 
mained perfect  for  a  considerable  time  ;  amau- 
rotic symptoms  supervened  during  the  course 
of  the  disease ;  but  even  after  the  occurrence 
of  opacity  of  the  cornea  in  consequence  of  in- 
flammation, the  patient  could  still  distinguish 
light.  Hearing  appears  to  have  been  affected 
in  most,  if  not  all  the  cases,  in  which  the  dis- 
ease had  attained  a  considerable  degree;  it  was 
so  in  the  case  seen  by  the  author ;  the  sense  of 
contact  would  seem  associated  with  the  perfect 
exercise  of  the  sense.  The  facial  muscles  re- 
tain their  contractile  power;  in  the  instance 
alluded  to,  though  the  temporal  and  masseter 
seemed  quite  paralyzed,  the  buccinator  acted 
with  energy  as  ascertained  by  holding  the  cheek 
between  the  finger  and  thumb  during  its  con- 
tractions ;  the  slight  want  of  adjustment,  which 
may  occur  about  the  mouth,  seems  caused  by 

*  Magendie,  Bell. 


the  want  of  sensation  in  the  lips.  Lastly,  in 
all  such  cases  the  eye  of  the  affected  side  is 
liable  to  have  inflammation  excited  in  it  by 
incidental  causes  ;  for  the  most  part  this  occurs 
at  an  advanced  stage  of  the  disease,  and  can  be 
referred  to  some  exciting  cause ;  it  is  attended 
by  but  little,  if  any  pain,  and  opacity  of  the 
cornea  is  an  usual  result.* 

(For  the  Bibliography  see  Nerve.) 

(B.  Alcock.) 

FOETUS,  Gr.  wnpa. ;  Ft,  foetus;  Germ. 
die  Frucht ;  (normal  anatomy).    See  Ovum. 

FOETUS  (abnormal  anatomy).  Considering 
the  peculiar  circumstances  of  the  foetus  in  utero, 
we  would,  at  first  sight,  be  inclined  to  suppose 
that,  although  of  course  exposed  to  the  risk  of 
injury  from  accidents  or  diseases  occurring  to 
the  mother,  it  would  not  be  liable  to  many  or 
serious  accidents  of  its  own ;  nevertheless,  ob- 
servation and  experience  soon  reveal  to  us  a 
very  different  state  of  facts,  and  force  upon  us 
the  sad  truth  that  the  seeds  of  life  are  often 
sown  adulterated  with  those  of  infirmity  and 
decay,  that  disease  may  mutilate,  and  death 
destroy,  even  before  our  entrance  into  life  ;  for 
as  far  as  investigation  has  enabled  us  to  reach, 
we  have  reason  to  believe  that  the  child  before 
birth  is  not  only  liable  to  certain  affections 
which  may  be  considered  peculiarly  its  own, 
but  is  also  subject  to  almost  all  those  which 
affect  the  adult. 

Of  these  affections  some  appear  to  be,  1. 
strictly  innate  in  the  constitution  of  the  foetus; 
2.  some  communicated  by  infection  from  the 
mother's  system  ;  3.  some  from  the  father's  sys- 
tem, or  perhaps  through  that  of  the  mother, 
she  herself  not  being  the  subject  of  the  affection 
entailed,  as  in  certain  forms  of  syphilis,  scrofula, 
and  small-pox  ;  4.  some,  from  strong  mental 
impressions  on  the  mother;  5.  some,  arising 
from  morbid  alterations  in  the  envelopes  of  the 
ovum,  the  placenta,  and  cord,  or  in  the  uterus 
itself;  6.  some,  from  the  influence  of  external 
agents,  as  falls,  blows,  pressure,  &c. 

The  investigation  of  these  abnormal  con- 
ditions is  invested  with  a  deep  interest,  not 
only  as  an  important  pathological  inquiry, 
but  as  conducive  to  the  adoption  of  mea- 
sures calculated  to  be  beneficial  to  both  mo- 
ther and  child ;  to  the  child,  by  suggesting 
the  strong  necessity  for  preventing  the  exposure 
of  the  mother  to  influences  likely  to  affect  the 
welfare  of  her  unborn  offspring,  as  well  as  for 
removing  their  effects  by  proper  remedial 
means  :  and  to  the  mother,  by  affording  us 
occasionally  information  of  the  existence  of 
diseased  taints  in  her  system,  of  which  we 
might  otherwise  long  remain  ignorant ;  or  by 
guarding  her  against  the  ill  effects  of  unhealthy 
states  of  the  child ;  for,  although  each  indivi- 
dual has  a  separate  existence,  there  is  at  the 

*  Mayo,  Commentaries  and  Physiology  ;  Bell, 
Philosoph.  Transactions  and  on  Nerves,  1830 ; 
Serres,  Journal  de  Physiologic,  t.  viii ;  Noble, 
Medical  Gazette  ;  Bishop,  Medical  Gazette,  vol. 
xvii. 


FCETUS. 


same  time  a  very  close  and  intimate  mutual 
dependence  of  the  one  on  the  other;  and,  con- 
trary to  what  we  would  at  first  expect,  the 
health  of  the  mother  is  more  apt  to  suffer  from 
morbid  conditions  of  the  foetus  in  utero  than  is 
the  latter  to  be  injured  in  its  developement  by 
the  state  of  the  mother's  system.  Thus  we  see 
how  great  a  disturbance  is  often  caused  in  the 
maternal  system  by  a  blighted  ovum,  or  a  dead 
and  putrid  foetus  ;  while,  on  the  other  hand, 
we  frequently  observe  that  women  in  states  of 
the  most  infirm  health,*  both  mental  and  bo- 
dily, nay  even  when  sinking  under  the  ravages 
of  some  wasting  disease,  or  depressed  and  worn 
out  by  mental  suffering,  by  want  of  food  or  ex- 
cessive fatigue,  give  birth  to  full-grown  and 
well-thriven  children. 

The  affections  to  which  the  foetus  is  liable 
vary  not  a  little  according  to  the  period  of  its 
existence  at  which  we  consider  it ;  during  the 
earlier  periods,  when  the  formative  process  is 
in  most  active  operation,  and  the  developement 
of  the  different  organs  is  proceeding  rapidly, 
many  important  and  remarkable  organic  altera- 
tions take  place ;  some  from  arrest  of  develop- 
ment caused  by  imperfection  in  or  morbid 
alteration  of  the  structures  of  the  ovum  ;  some 
by  destruction  of  parts  already  formed,  by 
atrophy  or  inflammation,  or  both  conjoined  ; 
some  by  the  effects  of  excessive  secretion  and 
the  consequent  unnatural  distension,  &c; 
while  those  affections,  to  which  more  strictly 
belong  the  name  of  diseases,  affect  the  more 
matured  foetus,  whose  organization  approaches 
more  closely  that  of  the  new-born  child. 

In  order  to  give  a  full  account  of  the  morbid 
and  abnormal  conditions  of  the  foetus,  we 
should  embrace  also  those  of  its  appendages 
or  surrounding  structures  of  the  ovum  ;  these, 
however,  will  be  alluded  to  at  present  only  so 
far  as  is  absolutely  unavoidable,  as  they  will 
receive  full  consideration  in  the  articles  Ovum 
and  Placenta  :  and  in  like  manner  several 
varieties  of  malformation  will  be  with  more 
propriety  described  under  the  head  of  Mon- 
strosity, while  others  will  be  found  under  the 
account  of  the  different  organs  concerned. 

The  germ,  even  before  its  vivification  in  the 
ovary,  may  have  a  morbid  taint  communicated 
to  it  from  the  system  of  the  female  in  whom  it 
resides,  or  from  that  of  the  man  with  whom  she 
cohabits,  so  that  the  tendency  to  disease  or 
malformation  sometimes  precedes  the  first  im- 
pulse that  leads  to  the  establishment  of  life. 
Another  source  of  abnormal  conditions  in  the 
foetus  occurs  in  the  cohesion  or  intus-susception 
of  germs,  in  consequence  of  more  than  one 
ovulum  being  contained  within  the  same  vesi- 
cle ;  under  which  circumstances  unnatural 
union  may  take  place  between  two  foetuses, 
and  give  rise  to  the  production  of  such  anoma- 
lies in  organization  as  the  Siamese  twins,  or  to 
other  forms  of  foetal  duplicity,  more  or  less  re- 
sembling the  remarkable  instance  represented 
in  the  annexed  sketch  of  two  children  born  a 

*  See  several  instances  recorded  by  Mauriceau, 
Malad.  <les  femmes  grosses,  vol.  ii.  obs.  439,  497, 
530,  622,  (529,  656. 


few  years  since  at  Boyle,  in  the  county  of  Ros 
common. 


Fig.  146. 


They  were  born  alive,  and  lived  for  more 
than  a  week  ;  after  death  they  were  sold  to  the 
College  of  Surgeons  in  Dublin,  in  whose  mag- 
nificent Museum  a  preparation  of. their  skeleton 
is  preserved.*  The  writer  lately  received  from 
the  President  of  the  College  of  Physicians,  Dr. 
Croker,  two  hen's  eggs  united  at  their  end  by 
a  connecting  stalk  as  thick  as  one's  little  finger, 
which,  in  common  with  the  two  eggs,  was 
covered  by  a  tough  white  membrane. 

From  intus-susception  of  one  germ  within 
another,  arise  also  some  very  singular  pheno- 
mena, such  as  the  existence  of  perfect  teeth  set 
in  bony  sockets,  long  hair,  &c.  in  situations 
far  remote  from  those  in  which  such  structures 
are  naturally  formed ;  and  the  still  more  extra- 
ordinary fact  of  foetuses  being  found  within  the 
bodies  of  males;!  facts  which,  in  the  opinion 
of  the  writer,  can  be  explained  only  on  the 
supposition  of  original  intus-susception  of 
germs,  constituting  that  abnormal  condition 
which  has  been  called  monstrosity  by  inclu- 
sion ;X  an  accident  which  appears  to  be  by  no 
means  confined  to  the  germs  of  the  mammalia 
nor  even  of  the  animal  kingdom.  The  writer 
has  in  his  museum  a  small  egg  about  as  large 
as  a  gooseberry,  which  was  found  within  ano- 
ther egg  of  the  common  hen,  which  also  oc- 
curred to  IIarvey,§  who  says,  "  I  have  seen  an 
exceeding  small  egge,  which  had  a  shell  of  its 
own,  and  yet  was  contained  within  another 
egge,  greater  and  fairer  than  it,  which  egge  also 
had  a  shell  too.  And  this  egge  I  shewed  King 
Charles  my  most  gracious  master  in  presence 

*  See  also  case  by  Dr.  Alcock  in  Dublin  Medical 
Essays,  vol.  ii.  p.  33,  and  Hall  on  the  Ca?sarean 
operation,  p.  470. 

t  Med.  Chir.  Trans,  vol.  i.  p.  234,  case  of  a 
foetus  found  in  a  young  man,  by  Nathaniel  High- 
more,  1815. 

t  See  Archives  Generales  de  Medecine,  torn.  vii. 
p.  355. 

$  Exercitation  xi.  pp.  50,  51  ;  Ent's  translation. 


318 


FCETUS. 


of  many  others  ;  and  that  very  year  cutting  up 
a  large  lemon,  I  found  another,  small,  but  yet 
a  perfect  lemon  in  it,  which  had  also  a  yellow 
rind." 

Many  other  instances  of  anomalies  resulting 
from  cohesion  and  intus-susception,*  might  be 
referred  to,  but  they  will  find  their  place  with 
more  propriety  under  the  article  Monstrosity. 

Mislocation  of  the  germ  during  its  growth 
and  development  is  well  known  to  be  produc- 
tive of  serious  consequences,  not  only  to  the 
foetus,  but  unfortunately  involves  great  danger 
to  the  mother  also,  as  in  those  instances  in 
which  it  has  been  developed  in  the  ovary ,f  the 
Fallopian  tube,  the  cavity  of  the  abdomen,  or 
in  the  substance  of  the  uterus  constituting  in- 
terstitial pregnancy.  J 

Atrophy. — A  very  common  occurrence  to 
the  foetus  in  utero  is  atrophy,  or  a  complete 
arrest  of  growth  from  disease  attacking  its  en- 
velopes, especially  the  placenta  or  cord;  in 
which  case,  a  deficient  and  unhealthy  supply 
of  nutrition  is  furnished  to  the  child,  which 
either  perishes  completely  or  has  its  develop- 
ment retarded  to  such  a  degree,  as  not  to  pre- 
sent dimensions  or  characters  corresponding  to 
perhaps  half  the  period  that  has  really  elapsed 
since  conception ;  as  happened  in  the  follow- 
ing case :  a  lady  who  menstruated  in  the  last 
week  of  July,  began  about  the  middle  of 
August  to  exhibit  unequivocal  symptoms  of 
pregnancy,  which  proceeded  regularly  till  the 
middle  of  October,  when  indications  of  threat- 
ened abortion  appeared,  with  pain,  and  the  re- 
peated expulsion  of  large  coagula  and  sub- 
stances of  various  appearances.  After  this,  the 
previously  existing  symptoms  of  pregnancy  en- 
tirely disappeared,  and  it  was  supposed  that 
miscarriage  had  occurred  and  that  the  ovum 
had  escaped,  unnoticed,  amidst  the  masses  of 
coagula.  The  lady  resumed  her  ordinary  habits 
and  went  into  society  as  usual,  without  expe- 
riencing any  uneasiness  or  unhealthy  symptom, 
except  irregular  uterine  discharges,  which  were 
supposed  to  be  menstrual :  so  matters  proceed- 
ed until  the  7th  January,  when,  after  a  long 
drive,  she  was  seized  with  periodical  pains  ac- 
companied by  smart  uterine  haemorrhage,  in 
consequence  of  which  I  was  sent  for.  I  found 
the  os  uteri  open  and  an  ovum  partly  protruded 
through  it,  this  I  succeeded  in  disengaging  and 
bringing  away ;  on  examination  it  presented 
the  general  appearances  as  to  size,  form,  and 
growth  of  the  foetus,  of  an  ovum  of  less  than 
two  months,  but  the  placenta  was  as  large  and 
as  much  formed  as  it  should  be  at  three  months, 
and  was  moreover  quite  unhealthy,  being 
throughout  affected  with  what  is  usually  called 
the  tubercular  state  of  that  organ  ;  the  foetus 
seemed  perfectly  healthy,  but  very  small ;  and 
the  umbilical  cord  was  only  about  half  an  inch 
in  length,  much  hypertrophied,  being  sud- 
denly enlarged  on  leaving  the  placenta,  to  three 

*  See  l)ublin  Journal  of  Medical  Science,  vol.  iv. 
p.  294,  and  as  before  note  f- 

t  See  Dub.  Med.  Journ.  vol.  ii.  p.  195. 

%  See  a  full  account  of  this  subject  in  Memoires 
by  Breschet  and  Geoffroy  St.  Hilaire ;  Repertoire 
Generate  d'Anatomie,  &c."   No.  1.  pp.  72,  75,  91. 


or  four  times  its  natural  diameter,  and  a^ain  as 
suddenly  contracted  almost  to  a  thread,  where 
it  joined  the  abdomen  of  the  foetus.  See  sub- 
joined sketch,  of  the  natural  size. 

Fig,  147. 


Cruveilhier*  relates  the  particulars  of  a  case 
in  which  the  effect  of  disease  of  the  placenta  in 
producing  atrophy  of  the  foetus  was  strikingly 
shewn  in  twins  at  the  sixth  month,  one  of  whom 
possessed  the  full  development  and  characters 
belonging  to  that  period,  but  the  other,  whose 
portion  of  the  joined  placentae  was  thin  and  un- 
vascular,  presented  a  size  corresponding  to  not 
more  than  three  months,  as  shewn  in  Jig.  148. 

In  another  case,  formerly  under  the  writer's 
care,  the  foetus  expelled  at  the  ninth  month  had 
only  grown  during  the  first  three.f 

Such  cases  as  the  above  possess  an  interest 
and  a  demand  on  our  attention  of  a  very  im- 
portant kind,  as  illustrative  of  the  necessity  for 
carefully  examining  into  the  state  of  the  foetal 
appendages  as  to  their  healthy  condition  or 
otherwise,  before  we  venture  to  pronounce  an 
opinion  on  the  time  that  has  elapsed  since  con- 
ception, merely  from  the  size  or  general  ap- 
pearance of  an  ovum  or  foetus  shewn  to  us  ; 
for  here  we  have,  in  one  instance,  an  ovum,  the 
size  of  which  and  that  of  the  contained  foetus, 
would  indicate  a  period  of  two  months'  preg- 
nancy only,  whereas  Jive  ?nonths  had  really 
elapsed  from  the  time  of  conception,  for  the 
parties  had  not  cohabited  since  the  time  of  the 
threatened  abortion ;  and  in  the  other  case  an 
ovum  of  three  months'  growth  is  expelled  nine 
months  after  conception.  Now,  in  either  case, 
had  the  husband  happened  to  die,  or  to  have 

*  Anatomie  Pathologique,  liv.  vi.  pi.  vi ;  see 
also  Graetzer,  die  Krankheiten  des  foetus,  p.  83. 

t  See  my  Exposition  of  the  Signs  of  Pregnancy, 
&c.  pp.  96,  7,  and  also  pp.  210,  11,  and  259,  60, 
of  same  work. 


F(ETUS. 


319 


Fig.  148. 


gone  from  home,  shortly  after  the  time  of  con- 
ception, and  the  accident  to  have  occurred  in 
the  same  way,  the  female  might  have  sustained, 
though  most  unjustly,  a  severe  injury  to  her 
reputation. 

Hernia. — Hernia  is  a  very  frequent  occur- 
rence in  the  fcetus,  especially  at  the  umbilicus, 
where,  in  the  earlier  periods  of  fetal  life,  the 
anterior  wall  of  the  abdomen  is  deficient  and 
the  intestines  covered  by  the  expansion  of  the 
sheath  of  the  cord,  into  which  they  project,  in 
some  instances  considerably ;  of  this  there  are 
several  specimens  in  the  writer's  museum  ;  not 
unfrequently  this  natural  deficiency  remains 
up  to  the  time  of  birth,  and  congenital  umbi- 
lical hernia  is  found  in  the  child. 

In  the  simpler  forms  of  this  affection  the  her- 
nial sac  contains  intestine  only,  but  in  other 
instances  which  have  occurred  to  the  writer, 
some  of  which  also  he  has  preserved,  it  con- 
tains the  liver  and  stomach  in  addition  to 
almost  the  whole  tract  of  intestines:  such  ag- 
gravated forms  are  in  general  connected  with 
other  malformations,  such  as  spina  bifida,  spon- 
taneous amputation,  &c.  which  combinations 
are  noticed  under  their  respective  heads  in  the 
present  article.  In  a  specimen  which  occurred 
recently  in  the  writer's  practice  the  liver  was 
protruded  into  the  sheath  of  the  cord,  but  all 
the  rest  of  the  abdominal  viscera  were  con- 
tained in  the  natural  cavity.  Inguinal  hernia 
sometimes  exists  before  birth,  but  is  rare.  Her- 
nia cerebri  is  noticed  elsewhere. 

Diaphragmatic  hernia,  or  protrusion  of  the 
intestines  through  the  diaphragm  into  the  ca- 


vity of  the  thorax  is  of  rather  rare  occurrence, 
or  perhaps,  more  properly  speaking,  is  less 
frequently  observed,  because  it  presents  no 
external  physical  alteration  of  form  to  attract 
attention. 

Like  umbilical  hernia  in  the  fcetus,  it  is  the 
result  of  incomplete  developement,  because  in 
the  earlier  periods  of  fatal  life  the  diaphragm 
does  not  exist,  and  the  thoracic  and  abdominal 
cavities  are  one  ;  and  as  the  muscle  afterwards 
becomes  developed  from  its  circumference  to- 
wards the  centre,  there  occurs  occasionally  an 
arrest  of  formation,  and  in  consequence  an 
aperture  is  left,  through  which  the  intestines 
and  other  abdominal  viscera,  as  they  increase 
in  size,  pass  into  the  cavity  of  the  thorax,  dis- 
placing the  heart  and  lungs,  the  latter  of  which 
organs  are  thereby  frequently  so  pressed  upon 
that  their  developement  is  prevented,  and  there 
is  sometimes  but  a  very  small  portion  of  them 
discoverable,  especially  of  the  one  at  the  side 
where  the  hernia  principally  exists;  which,  in 
a  vast  majority  of  the  cases  which  have  been 
met  with,  has  been  the  left,  and  then  the  heart 
has  been  pushed  over  to  the  right  side,  where 
its  pulsations  in  children  born  alive  have  some- 
times given  the  first  intimation  of  the  existence 
of  the  lesion  under  consideration.  In  general, 
children  so  affected  in  utero  have  been  either 
still-born,  or  have  died  very  soon  after  birth,  a 
consequence  which  it  appears  reasonable  to 
suppose  results  from  the  state  of  the  lungs. 
But  in  some  instances  the  children  have  sur- 
vived under  such  circumstances.  Becker  saw 
one  that  lived  five  years ;  and  in  a  case  re- 
corded by  Diemerbroeck,  where  the  diaphragm 
was  entirely  absent,  the  child  lived  seven  years, 
annoyed  only  with  a  frequent  cough.  Riviere 
and  J.  L.  Petit  mention  instances  of  life  much 
more  prolonged,  in  the  same  condition. 

The  writer  has  before  him  a  beautiful  speci- 
men of  this  abnormal  condition,  for  the  oppor- 
tunity of  examining  which  he  is  indebted  to 
Dr.  E.W.  Murphy,  as  well  as  for  permission 
to  have  a  drawing  taken  from  the  preparation 
in  his  possession.    (See  fig.  149.) 

The  opening  in  the  diaphragm  in  this  case  is 
at  the  left  side,  rather  anterior  to  and  to  the 
left  of  that  which  naturally  transmits  the 
cesophagus,  and  appears  to  arise  in  this  case 
from  separation  of  the  fibres  of  the  muscle;  a 
very  large  quantity  of  the  small  intestine  is 
lodged  in  the  left  side  of  the  thorax,  from 
which  the  heart  is  pushed  away  over  to  the 
right;  the  right  lung,  which  lies  behind  the 
heart,  is  natural  in  structure,  but  the  left  does 
not  equal  in  size  half  the  kernel  of  an  almond, 
and  does  not  possess  the  natural  pulmonary 
structure,  but  appears  nearly  as  solid  as  the 
liver.  The  stomach,  spleen,  and  liver  were  in 
their  natural  situation.  The  child  had  also  a 
spina  bifida  tumour  which  covered  the  whole 
of  the  sacrum,  and  deformity  of  cne  hand, 
the  thumb  of  which  was  attached  by  a  small 
pedicle  to  the  side  of  the  index  finger.  In  a 
case  related  by  M.  le  Docteur  Anthony,*  which 
occurred  in  his  practice,  the  child,  which  lived 

*  See  Journal  Hebdomadaire.    Fevrier,  1835. 


320 


FCETUS. 


Fig.  149. 


Diaphragmatic  Hernia, 
a.  The  heart,  b,  b.  The  intestines  which  had 
passed  through  the  diaphragm  and  occupy  the  left 
side  of  the  thorax,  displacing  the  heart,  c,  c.  Por- 
tions of  intestine  below  the  diaphragm,  d.  The 
stomach,    e.  The  liver. 

half  an  hour,  had  no  external  appearance  of 
any  thing  abnormal;  but,  on  examination  after 
death,  the  left  side  of  the  diaphragm  was 
found  not  to  exist,  and  the  small  intestines 
and  spleen  were  contained  in  the  thorax ;  in  all 
other  respects  the  condition  of  the  child  exactly 
resembled  that  described  above.* 

Hernia  cerebri  or  eneephalocele. — The  af- 
fection to  which  these  names  are  applied  is  not 
of  unfrequent  occurrence  in  the  foetus.  It  con- 
sists of  a  tumour  protruding  from  the  cavity  of 
the  cranium  through  an  aperture  in  the  bony 
structure,  covered  externally  by  the  integuments, 
lined  internally  by  the  dura  mater  and  arach- 
noid, and  containing  portions  of  the  cerebrum 
or  cerebellum,  together  with  serous  fluid,  with 
which  the  cerebral  structure  is  in  general  infil- 
trated and  softened  down  ;  sometimes  the  con- 
tents of  the  tumour  appear  to  be  completely 
fluid. 

This  affection  is  most  frequently  situated  on 
some  point  of  the  central  line  of  the  head, 
commencing  at  the  root  of  the  nose  and  ter- 
minating at  the  foramen  magnum  of  the  occi- 
pital bone  ;  these  being  the  situations  in  which 
the  foetal  head,  during  a  considerable  period, 
consists  only  of  membrane;  the  writer  has  seen 
it  in  the  centre  of  the  forehead  at  the  .interior 
and  posterior  fontanelle  and  in  the  centre  of 
the  occipital  hone.  According  to  the  observa- 
tions of  Mr.  Adams,f  the  tumour  is  most  fre- 
quently situated  at  some  point  in  the  middle 
line  of  the  proper  occipital  portion  of  the  os 

*  For  other  instances  of  this  affection,  see  Ar- 
chives Generales,  torn.  vii.  p.  142.  Transactions 
Medicales,  torn.  xii.  p.  359. 

f  See  an  excellent  paper  by  him  in  the  Dublin 
Medical  Journal,  vol.  ii.  p.  321. 


occipitis,  as  in  Dr.  Collins's  case,  to  be  noticed 
presently ;  but  it  has  happened  to  the  writer  to 
observe  it  more  frequently  in  the  other  situa- 
tions above  mentioned.  In  one  of  the  cases 
related  by  Mr.  Adams,  it  occurred  just  over 
the  right  eye,  and  the  subject  of  it  had  reached 
his  twentieth  year  when  the  account  of  his  case 
was  published.    (See  fg.  150.) 


Fig.  150. 


In  such  instances  the  bony  vault  of  the  head 
is  usually  much  smaller  than  in  ordinary  cases, 
being  proportioned  to  the  diminished  quantity 
of  its  contents,  and  the  sutures  and  fontanelles 
are  found  closed. 

In  the  first  case  of  this  affection  which  came 
under  the  writer's  notice,  a  tumour,  about  the 
size  and  somewhat  of  the  shape  of  a  fresh  fig, 
hung  from  the  centre  of  the  child's  forehead 
down  over  the  face ;  it  was  only  partially  filled, 
and  apparently  with  a  gelatinous  fluid;  when 
compressed  towards  the  forehead  the  contents 
were  diminished,  but,  in  the  same  proportion, 
the  child  appeared  distressed,  and  the  features 
began  to  be  distorted,  the  vault  of  the  cra- 
nium was  in  a  great  measure  deficient  of  its 
proper  developement,  the  parietal  and  frontal 
bones  rising  very  little  above  the  base  of  the 
cranium,  when  they  turned  over  to  form  the 
roof  of  the  skull.  The  child  did  not  present 
any  other  external  deviation  in  form ;  it  lived 
ten  days,  taking  food,  digesting,  and  perform- 
ing the  other  common  functions  like  other  chil- 
dren, but  then  pined  away  and  died.  On  exa- 
mination after  death,  it  was  found  that  the 
bag  which  had  protruded  and  hung  over  the 
face  was  lined  by  the  dura  mater  and  arachnoid, 
that  the  cerebrum  was  entirely  absent,  as  was 
also  part  of  one  side  of  the  cerebellum;  the 
aperture  in  the  frontal  bone,  through  which  the 
hernia  passed,  was  situated  just  over  the  root 
of  the  nose,  in  the  line  of  the  suture,  was  about 
three-sixteenths  of  an  inch  in  diameter,  and 
with  smoothly  rounded  edges;  the  sutures  and 
fontanelles  were  quite  closed  up.    M.  Moreau, 


FCETUS. 


321 


not  long  since,  presented  a  nearly  similar  case 
to  the  Academy  of  Surgery  at  Paris. 

In  another  case,  the  cast  of  which  was  sent 
to  the  writer  by  Dr.  Gason  of  Enniskerry,  the 
hernia  appears  to  have  taken  place  at  the  ante- 
rior fontanelle.  J.  Cloquet  met  with  a  case 
where  it  protruded  through  the  posterior  fonta- 
nelle.* A  remarkable  case  of  this  affection, 
occurring  in  a  very  unusual  situation,  was  ob- 
served at  the  Hotel  Dieu  at  Paris  :  a  child  of 
about  a  year  and  a  half  old  was  admitted  on 
account  of  a  small  tumour,  supposed  to  be  a 
ganglion,  about  as  large  as  a  nut,  and  situated 
at  the  root  of  the  nose,  exactly  under  the  nasal 
process  of  the  frontal  bone.  At  birth  it  had 
been  only  as  large  as  a  pea;  it  was  increased  in 
size,  and  became  redder  when  the  child  cried; 
the  child  was  very  irritable;  pressure  on  the 
tumour  gave  pain,  and  produced  a  general 
agitation.  Dupuytren  suspected  that  the  tu- 
mour was  formed  by  a  prolongation  of  the 
brain  through  some  congenital  opening  in  the 
base  of  the  skull,  and  on  consulting  with  M. 
Breschet,  the  latter  declared  that  he  had  met 
with  a  precisely  similar  case,  in  which,  on 
dissection,  he  had  found  that  the  tumour  was 
formed  by  a  portion  of  one  of  the  anterior  lobes 
of  the  brain,  which  was  prolonged  through  a 
slit  in  the  centre  of  the  ethmoid  and  sphenoid 
bones  down  to  the  root  of  the  nose.t 

As  tumours  of  a  very  different  character 
are  frequently  observed  on  the  foetal  head  at 
birth,  it  is  of  consequence  to  be  satisfied  of 
the  diagnostic  characters  of  the  encephalocele, 
which  is  at  first  a  rather  tense,  smooth,  and 
semitransparent  tumour,  giving  generally  a 
more  or  less  distinct  sense  of  fluctuation ;  it 
afterwards  collapses  and  becomes  wrinkled  and 
smaller  in  dimension  ;  the  integument  over  it 
is  thin  but  not  discoloured,  not  unfrequently 
pale  :  in  shape  the  tumour  is  globular  or  oval, 
and  frequently  tapers  to  a  neck  where  it  issues 
from  the  head,  (see  Jig.  151,)  at  which  point  a 
circular  aperture  can  be  detected  in  the  bone, 
the  edges  of  which  are  in  general  smoothly 
rounded  off;  the  tumour  is  not  painful,  but,  if 
it  be  compressed  by  the  hand,  so  as  to  cause  a 


Fig.  151. 


*  Diet,  de  Med.  torn.  viii.  p.  52. 

t  La  Lancette  Francaise,  Mars,  1835. 

VOL.  II. 


considerable  diminution  in  its  volume,  the  child 
appears  to  suffer  much  distress,  sometimes 
has  the  features  slightly  convulsed  for  the  mo- 
ment, and  is  rendered  stupid  and  paralytic,  as 
under  other  circumstances  of  cerebral  oppres- 
sion ;  pulsations  are  to  be  felt  in  the  tumour 
synchronous  with  those  of  the  heart;  and, 
lastly,  the  volume  of  the  tumour  is  suddenly 
increased  by  any  effort  on  the  part  of  the  child, 
as  by  coughing,  straining,  crying,  &c. 

Most  children  so  affected  are  either  still- 
born or  live  but  a  very  short  time;  to  this, 
however,  there  are  exceptions;  one  has  already 
been  mentioned,  another  has  been  related  on 
the  same  authority,*  and  Guyenot  brought 
before  the  Royal  Academy  of  Surgery  in  1 774, 
a  man  of  thirty-three  years  of  age,  with  ence- 
phalocele in  the  forehead,  who  had  never  ex- 
perienced any  disturbance  of  his  intellectual 
faculties.  Lallemand  attempted  to  remove  a 
tumour  from  the  occipital  region  of  a  young 
woman  of  twenty-three,  under  the  idea  that  it 
was  a  wen ;  but  unfortunately,  on  attempting 
to  operate,  he  found  that  it  was  an  encephalo- 
cele ;  inflammation  ensued,  and  the  patient 
died. 

Spina  bifida. — An  affection  in  many  respects 
analogous  to  that  just  described  to  which  the 
foetus  is  liable,  is  that  which  has  received  the 
name  of  spina  bifida,  and  consists  of  a  tumour 
situated  on  some  part  of  the  spinal  column, 
most  frequently  over  the  lumbar  vertebra?,  but 
it  may  be  found  at  any  point  along  the  whole 
length  of  that  column.  The  writer  lately  saw  a 
case  of  it  in  which  the  tumour  was  situated  so 
high  on  the  cervical  vertebrae,  that  it  was  diffi- 
cult to  determine  whether  it  arose  there,  or  from 
the  base  of  the  occipital  bone.  A  similar  case 
is  recorded  by  Dr.  Collins,  in  which  a  child 
was  born  with  a  tumour  projecting  from  the 
back  of  the  head  nearly  as  large  as  the  head 
itself;  it  burst,  and  the  child  died  in  ten  hours: 
"  The  tumour  to  a  considerable  extent  was 
covered  with  hair,  the  remainder  being  bare 
skin  of  a  thin  texture,  with  a  blueish  tinge ; 
with  the  exception  of  one  spot  the  size  of  a 
shilling,  which  had  almost  the  appearance  of 
serous  membrane. 

"  The  ventricles  of  the  brain  were  much  dila- 
ted and  communicated  freely  with  the  sac.  The 
membranes  were  extremely  vascular,  and  the 
whole  contents  of  the  cranium  in  a  dark  con- 
gested state.  The  opening  through  which  the 
tumour  had  formed  was  about  three-eighths  of 
an  inch  in  diameter,  and  half  an  inch  behind 
the  foramen  magnum.  The  bones  of  the  head 
generally  were  very  imperfect  as  to  ossifi- 
cation, "f 

The  most  unusual  form  of  it  is  that  in  which 
the  tumour  appears  at  the  very  extremity  of  the 
sacrum,  where  it  joins  the  coccyx.  Ruysch, 
however,  met  with  an  instance  of  the  kind,  and 
Genga  with  another,  in  which  there  was  also 
hydrocephalus,  the  fluid  of  which  was  eva- 
cuated by  opening  the  tumour  on  the  spine. J 

*  lioc.jamcit.  p.  341. 

t  Practical  Treatise  on  Midwifery,  p.  511. 

:f  Vide  Morgagni,  epist.  xii.  art.  9. 

Y 


322 


FCETUS. 


A  case  occurred  not  long  since  in  this  city, 
under  the  observation  of  Dr.  Murphy,  in  which 
at  the  time  of  the  birth  of  the  child,  which 
presented  the  breech,  a  membranous  bag 
protruded  before  it,  and  was  supposed  at  the 
moment  to  be  the  membranes  of  the  ovum, 
but  it  was  found  to  be  the  covering  of  a  spina 
bifida  tumour,  over  which  the  integuments  were 
deficient :  it  was  of  considerable  size,  nearly 
equalling  that  of  the  child's  head,  and  sprung 
from  the  very  lowest  point  of  the  sacrum,  as 
represented  in  the  subjoined  sketch: — 


Fig.  152. 


In  another  instance,  for  the  observation  of 
which  the  writer  is  also  indebted  to  Dr.  Mur- 
phy, the  tumour  occupied  the  whole  length  of 
the  sacrum,  and  was  conjoined  with  diaphrag- 
matic hernia.  In  some  rare  instances  there  have 
been  more  than  one  tumour :  in  size  these 
tumours  vary  from  the  volume  of  a  small  nut 
to  that  of  a  child's  head  at  birth  ;  and  in  their 
form  there  is  also  considerable  variety,  some 
being  very  exactly  globular,  while  others  are  of 
the  long  oval,  some  pyriform  with  the  tapering- 
pedicle  next  the  spine,  and  others  broader  in 
that  situation  than  externally,  and  so  rather 
representing  the  form  of  a  cone.  As  a  general 
description  of  the  affection,  its  pathological 
anatomy  is  this :  there  is  a  deficiency  in  the 
posterior  arch  of  one  or  more  vertebra,  arising 
eitherfrom  imperfect  development  of  these  bones, 
or  their  division  ;  through  the  opening  thus 
caused,  protrudes  a  sac  consisting  of  the  in- 
vesting membrane  of  the  spinal  marrow,  which 
sac  is  in  general  covered  externally  by  the 
common  integuments,  which  are  sometimes  in 
a  healthy  state,  but  more  frequently  diseased, 
being  sometimes  extremely  attenuated,  either 
wholly  or  partially  and  sometimes  in  a  state  of 
ulceration,  or  approaching  to  a  state  of  gangrene ; 
occasionally  the  integuments  are  altogether  ab- 
sent, and  the  membranes  form  the  covering  of 
the  tumour  ;  the  contents  are  a  fluid  of  various 
characters  in  different  cases ;  appearing  some- 
times bloody,  puriform,  and  otherwise  con- 


taminated, but  when  presenting  its  more  natural 
serous  condition,  it  is  found,  like  that  of  hy- 
drocephalus, to  contain  a  smaller  proportion  of 
albumen  than  the  fluid  of  other  dropsies. 
Sometimes  the  fluid  contained  in  the  tumour 
can  be  made,  merely  by  pressure  on  the  latter, 
to  retreat  and  pass  along  the  spinal  canal  iuto 
the  ventricles  of  the  brain,  producing  the  sym- 
ptoms of  cerebral  compression ;  and  in  such 
cases  also,  as  in  encephalocele,  efforts,  as  of 
crying,  coughing,  &c.  produce  an  immediate 
increase  in  the  size  of  the  tumour :  and  in  the 
case  mentioned  by  Morgagni,  the  enlargement 
of  the  head  from  hydrocephalus  was  diminished, 
when  the  spina  bifida  tumour  was  opened  and 
its  contents  allowed  to  flow  out.* 

Spina  bifida  has  been  found  engaging  the 
whole  length  of  the  spinal  column,  which 
is,  however,  very  rare,  and  sometimes  it  has 
passed,  not  through  a  divided  or  imperfect 
vertebra,  but  through  a  space  accidentally  ex- 
isting between  the  last  lumbar  vertebra  and  the 
first  piece  of  the  sacrum.-j- 

This  affection  of  the  foetus,  though  some- 
times found  unaccompanied  by  any  other,  is  in 
many  instances  complicated  with  morbid  lesions 
of  an  important  kind,  such  as  hydrocephalus, 
malformation  of  the  lower  extremities,  which 
are  apt  to  be  curved  inwards,  or  otherwise 
distorted,  deficiency  in  the  coverings  of  the 
abdomen,  and  umbilical  hernia,  hare-lip,  &c.  : 
in  one  instance  in  the  writer's  museum,  in 
which  there  was  adhesion  between  the  foetus 
and  the  amnion,  spina  bifida  is  accompanied  by 
malformation  of  the  lower  limbs,  and  an  enor- 
mous umbilical  hernia,  in  which  are  contained 
almost  all  the  abdominal  viscera.};  (See  Jig. 
153.) 


fig.  153. 


b,  a  membranous  pouch,  which  contained  the 
abdominal  viscera  during  uterine  existence.  •. 

d,  the  placenta  and  its  membranes. 

e,  the  liver,   f,  intestines. 

g,  external  opening  of  vagina. 

h,  an  aperture  in  the  situation  of  the  meatus 
urinarius. 

I,  spina  bifida  tumour. 

*  Epist.  xii.  art.  9. 

t  Andral,  Mohrenheim,  Portal. 

J  [Some  time  ago  the  Editor  was  favoured  by  his 
friend  Mr.  Hale  Thomson,  Surgeon  to  the  West- 
minster Hospital,  with  an  opportunity  of  examining 
a  remarkable  case  of  double  spina  bifida.  There 


FCETUS. 


.323 


The  spinal  marrow  is  sometimes  healthy, 
but  more  frequently  it  is  morbidly  affected  and 
sometimes  deficient ;  it  is  sometimes  displaced 
from  the  spinal  canal  and  lodged  in  the  cavity 
of  the  tumour,  especially  when  the  latter  occurs 
over  the  lumbar  vertebra;  sometimes  the  cauda 
equina  has  been  contained  in  the  tumour,  and 
its  component  nerves  found  separated  and 
floating  in  the  fluid,  or  spread  over  the  walls  of 
the  tumour. 

Children  thus  affected  seldom  survive,  what- 
ever treatment  may  be  adopted ;  some  rare 
exceptions  have,  however,  been  met  with,  in 
which  life  has  been  continued  even  up  to 
adult  age;  as  in  the  case  related  by  Mr. 
Jukes,*  in  which  the  woman  had  arrived  at  the 
age  of  twenty  at  the  time  of  writing  the  ac- 
count ;  the  tumour,  which  had  been  at  birth 
about  the  size  of  a  pigeon's  egg,  had  acquired 
dimensions  much  greater  than  those  of  the 
head ;  after  birth,  the  limbs,  which  had  been 
well  formed,  became  in  a  few  years  curved 
inwards,  and  the  woman  was  gradually  reduced 
to  a  most  miserable  condition.  A  similar  case 
of  survival  to  the  age  of  twenty  is  mentioned 
by  Warner,  f 

A  case  has  been  recently  recorded  in  which 
an  enormous  tumour  of  this  kind  delayed  the 
delivery  of  the  body  of  the  child  for  two  hours 
after  the  birth  of  the  head,  which  it  equalled 
in  size,  extending  from  the  third  cervical  verte- 
bra to  the  eighth  rib,  and  containing  a  quart  of 
fluid,  which  communicated  with  the  ventricles 
of  the  brain. J 

were  two  tumours,  the  lower  one  of  very  consider- 
able size,  and  on  its  posterior  wall  constricted 
along  the  mesial  line  ;  this  tumour  occupied  the 
whole  sacral  region.  It  was  distended  by  a  clear 
straw-coloured  fluid  ;  and  an  imperfect  septum, 
corresponding  in  situation  to  the  constriction  already 
mentioned,  projected  into  its  cavity.  The  second 
tumour  was  in  the  lumbar  region,  and  seemed  to 
be  a  hernia  of  the  spinal  meninges,  occasioned  by 
a  deficiency  in  the  laminae  on  one  side  of  only  two 
lumbar  vertebrae ;  it  was  consequently  small,  and 
communicated  with  the  canal  by  a  narrow  neck. 
The  lining  membrane  of  this  tumour  was  over- 
spread by  an  intricate  plexiform  arrangement  of 
nerves.  In  this  case  there  were  several  malforma- 
tions ;  one  ankle-joint  was  in  a  state  of  luxation 
occasioned  by  the  non-developement  of  the  articular 
extremities  of  tbe  bones.  The  intestinal  canal  was 
very  imperfect,  the  small  intestine  composed  of  a 
very  few  coils,  and  only  the  ccecal  extremity  of  the 
large  existing,  which  opened  on  the  pubic  region 
of  the  abdominal  parietes.  The  bladder  was  absent, 
each  ureter  terminating  in  a  small  sac,  which 
opened  on  either  side  of  the  misplaced  anus  just 
mentioned.  For  a  space  about  an  inch  and  a  half 
in  diameter,  immediately  around  where  the  ureters 
and  intestine  opened,  the  skin  of  the  abdomen  was 
raw,  very  red,  and  resembled  greatly  the  exposed 
mucous  membrane  of  the  bladder  in  cases  of 
extrophy  of  that  viscus.  The  left  kidney  had  its 
hilus  directed  outwards  instead  of  towards  the 
spine  ;  the  ureter  consequently  turned  in  behind 
the  kidney  in  order  to  reach  its  destination.  The 
uterus  and  vagina  were  natural.  This  case  has 
already  been  alluded  to  in  a  note  at  page  390,  vol.  i. 
of  this  work.  Ed.] 

*  See  Lond.  Med.  and  Phys.  Journ.  vol.  xlvii. 
p.  106. 

t  Cases  in  Surgery,  4th  edit.  p.  134. 
t  See  Lancet,  No.  261,  p.  698. 


Cranial  tumours.- — It  has  been  already  sug- 
gested that  there  were  other  tumours  observable 
on  the  head  of  the  child  at  birth  of  a  totally 
different  character  from  the  encephalocele,  but 
which  might  be  mistaken  for  it ;  an  error  into 
which  it  is  said  that  the  celebrated  Ledran  fell : 
these  tumours  are  generally  the  result  of  pres- 
sure during  labour,  producing  ecchymosis  and 
sometimes  bloody  effusion  between  the  scalp 
and  the  cranial  bones ;  they  differ  in  all  respects 
from  the  encephalocele  ;  they  are  darker  co- 
loured, without  any  pulsation,  situated  over 
the  solid  part  of  the  bones,  especially  over  the 
parietal  of  one  or  other  side;  they  cannot  be 
diminished  at  the  instant  by  pressure,  nor  does 
pressure  cause  the  internal  distress  which  results 
from  it  when  applied  to  the  hernia  cerebri;  and 
lastly,  no  opening  can  be  ascertained  in  the 
bone ;  but  with  regard  to  this  last  point  of 
diagnosis,  I  wish  to  direct  attention  to  a  cir- 
cumstance calculated  to  embarrass  the  examiner 
and  lead  him  into  error;  in  examining  tumours 
of  this  kind,  it  is  not  unusual  to  find  around 
their  base  a  defined  and  slightly  elevated  cir- 
cular margin,  which  at  first  one  would  be  al- 
most certain  was  the  circumference  of  an  aper- 
ture in  the  bone,  but  on  further  examination  it 
will  be  found,  that  if  the  point  of  the  finger  be 
pressed  within  this  circular  margin,  it  will 
there  meet  with  as  decided  and  firm  a  resistance 
as  it  did  outside  of  the  base  of  the  tumour.  I 
have  known  this  peculiarity  lead  to  the  pro- 
nouncing of  a  very  erroneous  opinion  as  to  the 
nature  and  prognosis  of  such  a  tumour. 

These  tumours  have  been  found  to  contain 
bloody  serum,  or  pure  blood,  either  fluid  or 
coagulated,  and  sometimes  both ;  the  effusion 
takes  place  either  between  the  bone  and  the 
pericranium,  or  external  to  the  latter  and 
under  the  integuments  :  the  former  variety  has 
been  called  cephalsematome  by  Naegele,*  who, 
as  well  as  Schmitt,  has  given  an  account  of  it. 

Having  stated  that  these  bloody  tumours  are 
generally  the  result  of  pressure  during  labour, 
I  should  add  that  I  have  reason  to  believe  that 
they  are  formed  occasionally  quite  indepen- 
dently of  any  such  cause.  I  very  lately  at- 
tended a  patient  who  gave  birth  to  a  child 
which  had  hardly  arrived  at  seven  months,  with 
an  easy  and  expeditious  labour,  yet  the  infant 
had  a  very  large  tumour  covering  the  greater 
part  of  the  right  parietal  bone,  having  all  the 
characters  of  the  cephalarnatome,  and  was  not 
removed  till  (he  termination  of  a  month. 

Injuries  of  the  cranial  bones. — The  same 
causes  which  give  rise  to  the  formation 
of  the  bloody  tumours  just  described,  not 
unfrequently  produce  fractures  or  depres- 
sions of  the  flat  bones  of  the  cranium,  espe- 
cially of  the  parietals  ;  more  particularly  in 
cases  of  contracted  pelvis,  where  the  promon- 
tory of  the  sacrum  projects  considerably  in- 
wards ;  though  I  have  known  such  accidents 
happen  without  the  concurrence  of  any  such 
state  of  the  pelvis,  but  from  the  interposition 
of  an  arm  between  the  head  and  the  bony  wall 

*  Zeller,  Comment,  de  Cephalematomate,  &c. 
Heidelberg,  1822.  , 

y  2 


324 


FOETUS. 


of  the  pelvis :  in  one  case  where  the  labour 
required  version  of  the  child,  the  arm  got  be- 
tween the  side  of  the  head  and  the  pubes  and 
produced  so  much  difficulty  in  the  delivery, 
that  the  left  parietal  bone  was  completely 
depressed.  Siebold  has  reported  a  case  in  his 
journal,  in  which  the  labour  was  painful  and 
tedious,  and  the  child  was  born  dead  :  a  large 
bloody  tumour  was  found  over  the  right  parietal 
bone ;  and  on  exposing  the  bone,  it  was  tra- 
versed by  three  distinct  fissures  passing  in 
different  directions  :  no  instruments  had  been 
used.*  But  I  have  reason  to  know  that  these 
injuries  of  the  cranial  bones  may  occur,  not 
only  independently  of  contracted  pelvis,  but 
even  of  slow  or  difficult  labour.  I  some  time 
since  attended  a  lady  in  her  second  labour,  and 
after  about  three  hours  from  its  commencement, 
she  gave  birth  to  a  healthy  boy,  but  with  a 
depression  in  the  left  temporal  bone  which 
would  readily  have  contained  an  almond  in  its 
shell ;  by  degrees  the  depression  disappeared, 
and  at  the  end  of  a  few  months  no  trace  of  it 
remained  ;  the  lady's  first  labour  was  easy,  as 
were  also  those  that  succeeded  the  birth  of  this 
child,  and  no  such  injury  was  observable  in 
any  other  of  the  children.  More  recently  I 
was  informed  by  Mr.  Mulock,  of  a  case  in 
which,  on  the  subsidence  of  a  cranial  tumour, 
a  spicula  of  bone  was  felt  distinctly  projecting 
under  the  integuments ;  the  labour  had  been 
slow  but  natural.  When  these  injuries  of  the 
foetal  head  were  first  observed,  they  were  attri- 
buted to  violence  by  Haller,  Rosa,  and  others, 
the  error  of  which  opinion  was  first  perceived 
by  Roederer  and  Baudelocque,  and  it  is  need- 
less to  say  how  important  is  the  distinction, 
especially  in  a  medico-legal  point  of  view. 

Fractures  of  the  long  bones  have  been  ob- 
served sometimes  as  the  result  of  injuries 
sustained  by  the  mother,  but  in  other  instances 
independent  of  any  such  cause,  and  apparently 
depending  on  some  defect  in  their  composition. 
I  saw  an  instance  in  which  a  woman,  when 
eight  months  pregnant,  was  precipitated  from 
the  second  story  of  a  house  into  the  street,  by 
which  the  hip-joint  was  dislocated,  and  she  was 
otherwise  much  injured ;  she  fell  on  her  face, 
yet  the  uterus  was  not  ruptured ;  labour  came 
on  that  night,  and  the  child  was  born  dead 
with  several  of  its  bones  broken  :  the  woman 
recovered  well.  A  case  is  quoted  by  Duges  on 
the  authority  of  Carus,  in  which  a  woman  fell 
on  her  belly  and  caused  a  fracture  in  the  leg  of 
the  child,  which  was  born  with  the  fracture 
complicated  with  wounds  in  the  soft  parts ; 
gangrene  supervened  and  detached  entirely  the 
fractured  limb.f  Marcf  relates  a  case,  in 
which  all  the  bones  of  the  limbs  and  several 
others  were  found  fractured,  the  mother  not 
having  met  with  any  accident,  and  having  had 
an  easy  and  quick  labour ;  the  child  was  born 
alive  and  lived  for  some  days  :  on  examination 
after  death  the  number  of  fractures  were  found 

*  See  Med.  Chir.  Review,  No.  37,  Julv  1833, 
p.  211. 

t  Diet,  de  Med.  et  de  Chirurgie  Prat.  torn.  viii. 
p.  293. 

J  Diet,  des  Sc.  Med.  torn.  xvi.  p.  63. 


to  amount  to  forty-three,  some  of  them  just 
beginning  to  unite,  and  others  almost  com- 
pletely consolidated. 

In  a  case  which  occurred  to  Chaussier,  in 
which  also  the  labour  was  quick  and  easy,  and 
the  mother  had  not  sustained  any  previous  acci- 
dent, the  child  was  born  alive  and  survived 
twenty-four  hours ;  its  limbs  were  malformed, 
and  after  death  no  less  than  one  hundred  and 
thirteen  fractures  were  discovered  in  different 
conditions,  some  of  them  being  already  quite 
consolidated,  while  others  were  apparently 
quite  recent.* 

Fractures  independent  of  any  external  injury 
or  defect  of  nutrition  are  supposed  by  some  to 
be  produced  by  violent  spasmodic  contractions 
of  the  fetal  muscles,  which  are  capable  of  very 
energetic  efforts,  at  a  time  when  the  foetal  bones 
have  very  little  power  of  resistance.  It  appears 
reasonable  to  believe,  that  such  spasmodic 
action  of  the  muscles  might  be  induced  by 
causes  violently  disturbing  the  nervous  system 
of  the  mother,  since  we  know  that  such  in- 
fluences acting  on  a  nurse  will  cause  spasmodic 
and  convulsive  affections  in  the  child  at  her 
breast ;  and  we  further  know,  that  even  in  the 
adult  a  quick  muscular  effort  has  been  followed 
by  fracture  of  a  bone,  but  how  far  such  analo- 
gies are  applicable  to  explain  the  lesion  in 
question  I  would  not  pretend  to  determine. 

A  similar  explanation  has  been  supposed 
applicable  to  the  instances  of  dislocations  which 
have  been  discovered  in  the  foetus,  and  one  in 
particular  related  by  Chaussier  appears  to 
correspond  to  such  a  supposition.  A  young, 
delicate,  and  nervous  lady,  in  the  ninth  month 
of  pregnancy,  suddenly  felt  such  violent  and 
rapid  movements  of  the  child  that  she  was  near 
fainting;  these  tumultuous  motions  were  three 
times  repeated  in  the  course  of  ten  minutes, 
and  then  there  succeeded  a  perfect  calm ;  the 
remainder  of  the  pregnancy  passed  on  well, 
the  labour  was  easy,  the  child  was  pale  and 
weak,  and  had  a  complete  dislocation  of  the 
left  fore-arm.f  In  another  instance  mentioned 
by  Marc  J  there  were  found,  in  addition  to 
congenital  dislocation  of  both  hip-joints,  no 
less  than  seven  other  luxations. 

But  by  far  the  most  remarkable  pathological 
lesion  to  which  the  foetus  in  utero  is  subject,  is 
that  in  which  portions  of  its  limbs  are  removed 
by  a  process  which  has  been  with  propriety 
denominated  spontaneous  amputation. 

This  singular  fact  has  been  mentioned  by 
several  authors  of  credit,  as  Richerand,§  Desor- 
meaux,||  Billard,H  and  Murat,**  though  none 
of  them  appear  to  have  witnessed  any  case  of 
the  kind  themselves;  but  they  all  agree  in 

*  For  a  full  account  of  the  dissection,  see 
Bullet,  de  la  Fac.  de  la  Soc.  de  Med.  de  Paris, 
1813,  No.  3.  .  ,  T  .  no,« 

t  Discours  prononce  a  la  Matemite,  Juin  1812. 

X  Diet,  des  Sci.  Med.  t.  xvi.  p.  66.  See  also 
une  Memoire  sur  un  deplacement  originel  ou  con- 
genital de  la  tete  des  femurs,  par  M.  le  Baron  Du- 
puytren;  Repertoire  d'Anatomie,  t.  ii.  partie  1. 

I  Elemens  de  Phvsiologie,  p.  477. 
if  Diet,  de  Me.d.  t.  xv.  p.  404. 

II  Maladies  des  Enfans,  p.  623. 

**  Diet,  des  Sci.  Med.  t.  xvi.  p.  70. 


FOETUS. 


325 


regarding  it  as  simply  the  result  of  inflamma- 
tion and  gangrene.  Haller  evidently  was  not 
aware  of  any  such  case,  for  although  he  gives 
a  long  list  of  extraordinary  mutilations  of  the 
fcetus,  he  considers  them  as  the  result  of  im- 
perfect development  or  malformation,  and  not 
of  separation  or  removal  of  parts  already formed  ; 
for  he  expressly  objects  to  the  authors  who  have 
furnished  such  descriptions,  that  they  cannot 
even  quote  one  instance  in  which  "  manus 
truncata,  aliusve  artus,  in  membranis  fcetus 
seorsim  a  corpore,  repertus  sit."*  Having 
sought  with  diligence  through  authors,  the  only 
cases  which  I  have  been  able  to  find  are  those 
which  I  shall  now  briefly  mention. 

In  the  54th  volume  of  the  Lond.  Med. 
Phys.  Journ.  Mr.  Watkinson  states,  that  being 
in  attendance  on  a  lady  twenty  years  of  age  in 
her  first  labour,  which  was  natural  and  easy, 
he  discovered,  on  the  birth  of  the  child,  that 
the  left  foot  had  been  amputated  a  little  above 
the  ankle,  and  the  part  was  nearly  but  not 
quite  healed,  the  bones  protruding  a  little. 
The  child  was  alive,  but  survived  only  a  few 
minutes ;  on  making  further  search  the  ampu- 
tated foot  was  found  in  utero,  and  it,  also,  was 
nearly  healed.  There  did  not  appear  to  have 
been  any  haemorrhage  from  the  limb ;  the  sepa- 
rated foot  was  much  smaller  than  the  other;  it 
shewed  no  mark  of  putrefaction,  but  appeared 
to  be  in  a  state  of  perfect  preservation,  not 
being  even  discoloured.  The  mother  had  not 
met  with  any  accident  nor  any  particular  mental 
emotion,  and  she  was  sufficiently  independent 
to  render  unnecessary  any  over-exertion  on  her 
part.  Mr.  Watkinson  offers  no  opinion  on  the 
nature  or  cause  of  the  accident.  The  annexed 
sketch  represents  the  condition  of  the  parts. 


Fig.  154. 


Chaussierf  mentions  having  examined  two 
cases  in  which  separation  of  a  part  of  the  fore- 
arm had  taken  place  before  birth,  and  in  a 
third  case  he  found  the  separated  portion  of  the 
arm  and  hand  lying  apart,  and  the  stump  of  the 
limb  healed. 

*  Elemcnta  Physiologic,  t.  viii.  p.  135. 
t  Discours  prononc6  a  1'Hospice  de  la  Maternite, 
1812. 


Chaussier  also  attributes  the  accident  to  gan- 
grene as  the  cause  which  would  most  obviously 
account  for  its  production,  though  it  does  not 
appear  from  his  account  that  there  were  present 
any  of  the  pathological  evidences  of  that  con- 
dition ;  and  in  the  case  first  related  the  child 
was  born  alive,  and  it  is  expressly  mentioned 
that  neither  the  stump  of  the  limb  nor  the  part 
amputated  shewed  any  symptom  of  disorganiza- 
tion or  disease,  not  being  even  discoloured. 

The  next  case  was  one  occurring  in  my  own 
practice,  and  appears  to  me  of  great  importance 
as  exhibiting  the  amputation  absolutely  in  pro- 
gress, under  the  influence  of  the  agent  which 
I  believe  to  be  the  general,  and,  most  probably, 
the  invariable  cause  of  its  occurrence. 

About  eight  years  since  I  attended  a  patient 
under  circumstances  of  considerable  danger 
from  haemorrhage  attending  abortion  in  the  fiftli 
month,  and  on  the  expulsion  of  the  fcetus  its 
singular  conformation  fortunately  attracted  my 
attention  strongly,  and  induced  me  to  examine 
it  with  care.  The  head  was  mis-shapen  and 
monstrous,  the  brain  covered  only  by  integu- 
ment, and  towering  upwards  like  a  helmet 
over  the  head ;  but  the  circumstance  deserving 
of  especial  notice  was  the  appearance  of  com- 
plete ligaments  surrounding  the  limbs,  and  on 
examining  them  closely  I  found  that  they  con- 
sisted of  distinct  threads,  passing  from  both  hands 
downwards  to  the  legs  (seefig.  155) ;  at  one  end, 


Fig.  155. 


each  of  these  threads  or  fine  cords  had  formed 
a  complete  ligature  round  the  middle  of  each 
hand,  causing  a  distinct  depression  where  it 
passed,  the  part  of  the  hand  below  it  being 
almost  completely  undeveloped.  From  the 
hands  these  cords  descended  towards  the  legs, 
which  were  crossed,  and  surrounding  them  in 
this  position  just  above  the  ankles,  compressed 
them  so  tightly  that  fully  two-thirds  of  their 
whole  thickness  were  thereby  divided,  without, 
however,  causing  any  breach  in  the  skin;  nor 


326 


FCETUS. 


was  there  the  slightest  appearance  of  disease 
or  even  discolouration  of  any  of  the  parts,  but 
the  feet  were,  like  the  hands,  imperfectly  deve- 
loped and  mis-shapen.  The  mother  was  about 
twenty-five  years  of  age,  and  was  at  the  time 
labouring  under  fever,  but  had  been  previously 
in  perfectly  good  health,  and  had  not  met  with 
any  accident  either  in  the  way  of  bodily  injury 
or  mental  agitation. 

About  four  years  after  the  occurrence  of  the 
case  just  detailed,  another  was  brought  under 
my  observation  through  the  kindness  of  Dr.  J. 
Labatt. 

A  healthy  woman  gave  birth  to  a  still-born 
child  in  the  eighth  month  of  gestation ;  it  was 
affected  with  an  umbilical  hernia  of  great  size, 
formed  by  the  protrusion  of  the  liver,  stomach, 
and  small  intestines,  but  the  state  of  the  limbs 
is  the  point  of  interest  connected  with  our 
inquiry :  both  were  mis-shapen,  and,  as  hap- 
pened in  Mr.  Watkinson's  case,  the  left  exhibits 
this  remarkable  pathological  lesion,  and  exactly 
in  the  same  situation.  Just  above  the  ankle 
there  is  a  deep  depression  all  around  the  limb, 
and  sinking  to  such  a  depth  as  to  leave  only 
the  bones  and  skin  unaffected  by  it,  the 
diameter  of  the  undivided  part  being  less  than 
half  an  inch,  while  that  of  the  leg,  just  above 
the  depression,  is  an  inch  and  a  quarter.  The 
appearance  of  the  groove  is  exactly  such  as 
would  be  made  by  tying  a  string  very  tight 
round  the  plump  limb  of  a  child,  and  in  my 
opinion  could  not  have  been  produced  in  any 
other  way.  The  part  had  been  very  much 
handled  and  examined  by  several  before  I  saw 
it,  so  that  I  was  not  surprised  at  not  finding 
any  ligature  on  the  limb,  but  the  mark  of  it 
was  so  distinct  in  the  bottom  of  the  depression 
as  to  leave  no  doubt  of  its  previous  existence 
there  having  produced  the  constriction  of  the 
part.    It  is  important  also  to  observe,  as  con- 


Fig.  156. 


firmatory  of  this  view  of  this  matter,  that  the 
integuments  are  not  at  all  broken  or  divided, 
but  are  merely  carried  inwards  with  the  con- 
stricting agent,  so  that,  had  the  separation  of 
the  limb  been  completed,  each  stump  would 
appear  skinned  over,  except  at  the  ends  of  the 
bones,  and  so  present  the  appearance  of  being 
partially  haded,  as  described  by  both  Watkin- 


son  and  Chaussier:  the  foot  was  a  little  swollen 
and  somewhat  discoloured ;  it  seemed  turgid 
with  blood,  but  was  without  any  appearance  . 
whatever  of  gangrene. 

In  both  the  instances  here  before  us,  from 
the  condition  of  the  limbs  and  the  impossibility 
of  the  parts  under  the  ligatures  continuing  their 
growth  under  such  circumstances,  it  could 
scarcely  be  made  subject  of  doubt  that  had  the 
children  continued  to  live  and  grow,  the  parts 
of  the  limbs  below  the  constriction  would  have 
separated,  and  so  undergone  spontaneous  am- 
putation. 

The  next  case  to  which  my  attention  was 
drawn  was  one  very  politely  communicated  to 
me  by  Dr.  Tyson  West,  of  Alford,  Lincolnshire, 
in  consequence  of  his  becoming  acquainted 
with  my  account  of  this  matter.  Dr.  West 
attended  a  patient  at  the  Westminster  Lying-in 
Hospital  in  1805,  who,  after  a  natural  and 
easy  labour,  gave  birth  to  a  still-born  child 
which  had  but  one  leg,  the  other  limb  exhibit- 
ing positive  proof  of  having  been  spontaneously 
amputated  some  time  before,  the  stump  being 
partially  healed  and  nicely  rounded,  about  an 
inch  anrl  a  half  below  the  knee :  the  unhealed 
portion  of  the  stump  was  about  this  size.  /**S^ 
He  accounts  for  the  amputated  portion  /  A  \ 
of  the  limb  not  being  found  in  conse-i  WJ  B 
quence  of  the  occurrence  of  a  mostN^/ 
dangerous  accident  which  threw  all  the  parties 
concerned  into  great  alarm  and  confusion ;  but 
he  adds  that  it  struck  him  at  the  time,  and  he 
is  still  of  the  same  opinion,  that  the  division 
of  the  limb  was  effected  by  some  stricture 
round  it* 

When  first  announcing  the  discovery  of  this 
fact,  in  1832,f  I  stated  that  the  origin  of  these 
ligatures,  and  still  more  their  application  so  as 
to  stricture  the  limbs,  were  circumstances  on 
which  I  did  not  feel  prepared  to  pronounce 
an  opinion  with  any  reasonable  probability  of 
its  being  satisfactory,  and  I  am  sorry  that  five 
years'  additional  consideration  of  the  matter  has 
not  enabled  me  to  solve  the  difficulty  com- 
pletely ;  but  I  am  happy  to  find  that,  so 
far  as  I  have  ventured  to  point  out  a  proximate 
cause  of  this  singular  phenomenon,  my  views 
have  been  assented  to,  and  my  explanation 
adopted,  by  all  who  have  subsequently  ex- 
pressed their  opinions  on  the  subject,  and 
especially  by  Professor  Gurlt,  of  the  ltoyal 
School  of  Medicine  at  Berlin,  author  of  a 
work  on  pathological  anatomy,  (whose  investi- 
gations render  him  peculiarly  qualified  to  form 
an  opinion  on  such  a  subject,)  who  has  written 
a  commentary  on  my  original  paper,J  in  which 
he  adopts,  as  correct,  my  explanation  of  this 
curious  fact,  and,  in  addition,  undertakes  to 
account  for  the  formation  and  application  of 
the  ligatures. 

He  commences  his  observations  by  rejecting 
in  toto  the  notion  of  the  agency  of  gangrene : 
his  words  are :   "  To  explain  this  most  re- 

*  A  notice  of  this  case  was  inserted  by  Dr.  West 
in  the  Lond.  Med.  and  Surg.  Jomn.  for  1832,  vol.  i. 
p.  741. 

t  See  Dublin  Medical  Journal,  vol.  i.  p.  140. 
i  See  Medicinische  Zeitung,  1833,  N.  3,  p.  13. 


FOETUS. 


327 


markable  phenomenon,  the  utterly  unfounded 
hypothesis  has  been  formed,  that  these  spon- 
taneous separations  are  the  result  of  gangrene, 
although  there  are  no  traces  of  it  to  be  dis- 
covered on  the  stump,  it  being  actually,  to 
a  certain  extent,  healed,  and  no  change  of 
colour  to  be  seen  :"  and  he  immediately  adds, 
"  a  case  lately  observed  by  Montgomery  of 
Dublin  appears  to  contribute  a  natural  explana- 
tion of  this  remarkable  fact,  inasmuch  as  it 
indicates  the  cause  of  this  separation."  He 
then  repeats  the  details  of  my  first  case,  and 
proceeds  to  say  he  "  believes  that  both  the 
formation  of  these  threads,  and  the  amputation 
of  the  limbs,  which  are  most  probably  in  all 
cases  produced  by  them,  may  be  explained 
by  the  history  of  the  formation  of  the  fcetus." 
He  then  enters  into  a  minute  detail  of  facts 
well  known  to  all  who  are  acquainted  with 
the  mode  in  which  the  development  of  the 
fcetus  takes  place,  and  observes,  "  I  look  upon 
these  threads  as  prolongations  of  the  egg  mem- 
brane from  which  the  fcetus  grows,  whether 
this  skin  (or  membrane)  be  taken  as  the  navel 
bladder  or  the  amnion  :"  and  he  subsequently 
objects  to  their  being  considered  as  formed  by 
organized  lymph,  which  I  considered  them 
to  be,  and  still  remain  of  the  same  opinion. 

The  prolongations  of  the  membrane,  Gurlt 
thinks,  are  afterwards,  by  the  constant  motions 
of  the  fcetus,  twisted  into  slight  but  firm  cords 
or  threads,  which  may  involve  different  portions 
of  the  foetal  limbs,  (as  we  sometimes  find  the 
umbilical  cord  several  times  round  the  neck, 
or  other  parts  of  the  child's  body,)  so  as  to 
stricture  them  and  cause  their  separation  ;  and 
in  this  way  Professor  Gurlt  explains  the 
presence  of  the  ligatures  concerned  in  the  pro- 
duction of  spontaneous  amputation.  I  dissent 
from  this  as  a  general  explanation,  for  a  reason 
presently  to  be  stated ;  but  it  is  only  justice 
to  the  author  to  mention  that  the  condition 
of  both  the  children  which  I  examined  was 
in  other  respects  such  as  favours  his  theory, 
for  whenever  such  unnatural  adhesions  take 
place  between  the  amnion  and  the  fcetus,  they 
give  rise  to  a  monstrosity  of  a  peculiar  kind, 
and  this  is  observable  in  both  these  cases,  and 
in  others  also :  in  one  there  is  protrusion  of 
the  brain  and  monstrous  formation  of  the  head 
in  other  respects ;  and  in  the  other  the  liver, 
stomach,  and  great  part  of  the  intestines  were 
contained  in  a  hernial  sac,  external  to  the  body. 
But  notwithstanding  the  support  thus  derived 
from  analogy,  there  is  one  circumstance  which 
appears  fatal  to  the  explanation  when  applied 
to  the  first  case  described  by  me,  which  is, 
that  in  all  cases  where  these  membranous  con- 
nections have  been  observed  giving  rise  to 
monstrosity,  one  end  of  the  cord  or  thread- 
like band  has  always  been  found  attached  to 
the  amnion,  and  the  other  to  the  fcetus,  but 
here  both  ends  of  the  cords  are  attached  to 
the  limbs,  and  afford  no  evidence  of  having 
been  connected  with  the  amnion ;  and  it  was 
for  this  reason  that  I  abstained  at  first  from 
offering  the  explanation  now  proposed  by  Pro- 
fessor Gurlt,  which  I  then  thought,  and  still 
consider  inapplicable  to  the  specimen  which 


I  was  then  describing,  and  equally,  or  perhaps 
still  more  so,  to  that  described  by  Zagorsky, 
to  be  mentioned  presently,  see  Jig.  159  ;  though, 
at  the  same  time,  I  am  quite  ready  to  admit 
that  ligamentous  bands  so  formed  would  be 
fully  adequate  to  the  accomplishment  of  such 
an  effect  :  and  I  now  know  also  that  strictures 
from  another  source,  and  which  from  their 
nature  must  possess  very  little  constricting 
force  indeed,  are  in  some  instances  found 
sufficient  so  completely  to  act  on  and  indent 
the  limb,  that,  could  their  action  be  con- 
tinued, which,  however,  is  scarcely  possible, 
they  might  ultimately  induce  a  similar  mutila- 
tion. While  I  was  engaged  in  committing 
these  observations  to  writing,  I  received  a  most 
interesting  preparation  from  Dr.  W.  O'B. 
Adams,  in  which  the  coiling  of  the  umbilical 
cord  round  the  left  leg  of  the  foetus  at  three 
months  had  deeply  indented  it,  as  represented 
in  the  subjoined  ^.  157.    Here,  it  will  be 


Fig.  157. 


observed,  at  least  three-fourths  of  the  thick- 
ness of  the  limb  are  divided  by  the  pressure 
of  the  umbilical  cord,  which  was  coiled  around 
it,  and  which,  both  in  this  and  Jig.  158,  is 
removed  from  the  strictured  part  where  it 
originally  lay,  in  order  to  show  more  distinctly 
the  effect  produced  by  it. 

Within  the  last  few  months  another  instance 
of  the  same  effect  produced  by  the  same  agent 
just  above  the  left  knee  of  a  foetus  at  about 
the  same  period  of  growth,  occurred  with  a 
patient  of  the  writer's,  and  under  his  hnraie- 


328 


FCETUS. 


diate  observation,  as  shewn  in  the  annexed 
figure,  158. 


Fig.  158. 


I  am  very  much  disposed  to  believe  that 
Morgagni  witnessed  a  fact  of  this  kind;  at 
least  his  description  of  the  appearance  in  a 
monstrous  foetus  between  the  fifth  and  sixth 
month,  greatly  resembles  it,  of  which  he  says, 
"  All  the  limbs  were  in  a  very  bad  state,  the 
upper  limbs  from  the  elbows  downwards ; 
for  to  the  arms,  which  were  very  short  and 
distorted,  distorted  hands  were  likewise  added. 
And  the  inferior  limbs  terminated,  likewise,  in 
distorted  feet,  but  the  left  leg  was  either  broken 
from  the  funiculus  umbilicalis  having  been  ap- 
plied round  it,  or  was  more  distorted  than 
the  other  parts:"*  and  he  afterwards,  with 
great  reason,  conjectures  that  the  binding  of 
the  cord  round  the  leg  may  have  been  the 
cause  of  the  child's  death,  by  interrupting 
the  circulation  through  it.  It  is  a  very  ex- 
traordinary fact,  that  in  every  one  of  these 
cases,  as  well  as  in  several  others,  the  injury 
was  sustained  by  the  left  extremity. + 

In  the  course  of  the  last  year  Dr.  Simpson 
of  Edinburgh  published  an  excellent  paper  on 
this  subject;!  into  which  he  has  collected  a 
vast  quantity  of  curious  information  and  many 
most  important  cases  from  authors,  to  which 

*  Epistle  xlviii.  art.  53,  vol.  ii.  p.  758,  of 
Alexander's  translation. 

f  For  other  instances  of  impressions  made  on 
the  foetal  limbs,  &c.  see  Van  de  Laar,  Obs.  Obstet. 
Med.  p.  41,  and  tab.  11  ;  Meckel,  Patholog.  Anat. 
Bd.  ii.  s.  137; 

Sandifort,  Thesaurus,   torn.  iii. 
p.  235,  tab.  11,  fig.  5. 

%  See  Dublin  Medical  Journal  for  November, 
1836,  vol.  x.  p.  220. 


he  has  added  not  a  few  from  his  own  obser- 
vation, together  with  several  highly  apposite 
remarks ;  and  I  am  happy  to  find  that  he  also 
assents  to,  and,  indeed,  strongly  confirms  my 
view  both  as  to  the  agent  which  produces  the 
change  and  its  consisting  of  organized  lymph, 
such  as  is  usually  elaborated  under  the  influence 
of  inflammatory  action,  from  which  it  is  well 
known  that  several  varieties  of  foetal  deformities 
arise ;  *  and  it  is  a  matter  of  every  day  ob- 
servation how  completely  lymph  so  effused 
will  be  converted  into  distinct  firm  threads, 
uniting  opposite  serous  surfaces,  especially 
those  which  move  freely  on  each  other,  as  the 
pleurae  and  the  peritoneal  coverings  of  the  ab- 
dominal viscera.f 

From  the  cases  referred  to  by  Dr.  Simpson, 
I  shall  now  notice  three  which  appear  more 
particularly  illustrative  of  the  true  nature  of 
this  remarkable  lesion,  and  confirmatory  of  my 
original  account  of  it. 

Zagorsky  has  described  \  a  malformed  foetus 
of  the  fifth  month,  which,  in  addition  to  several 
other  deformities,  was  deficient  of  the  right 
leg,  the  thigh  ending  in  a  rounded  and  cicatrized 
stump,  in  the  centre  of  which  was  a  small 
projecting  point:  from  this  was  prolonged  a 
slender  thread-like  membrane,  strong  in  pro- 
portion to  its  size,  that  ran  directly  across  to 
the  left  leg,  which  it  encircled,  a  little  above 
the  ankle,  like  a  tightened  ligature,  see  fig.  159, 
and  formed  in  it  a  depression  of  considerable 
depth,  while  the  portion  of  the  extremity 
below  the  ligature  was,  as  well  as  the  appended 
foot,  rather  tumefied.  From  about  the  middle 
of  the  transverse  thread-like  membrane  a  small 
body  of  an  oblong  form  was  suspended,  which, 
on  examination,  proved  to  be  the  right  foot 
perfectly  formed,  as  its  general  outline  and 
five  toes  demonstrated,  but  not  larger  in  size 
than  the  foot  of  a  foetus  of  the  tenth  or  twelfth 
week. 

Beclard  mentions  §  the  case  of  a  very  de- 
formed hydrocephalic  foetus,  whose  left  leg  was 
divided  by  a  transverse  depression  that  pene- 
trated as  deep  as  the  bones,  and  resembled  that 
which  would  have  been  produced  by  a  tight 
ligature.  The  two  opposite  surfaces  of  this 
indentation  were  both  cicatrized,  and  almost 
touching  one  another.  "  It  is  evident,"  says 
Beclard,  "  that  if  this  foetus  had  remained  in 
utero  for  some  time  longer,  it  would  have  been 
born  with  an  amputated  and  cicatrized  leg,  the 
remains  of  which  might  have  been  found  in  the 
liquor  amnii." 

*  See  Geoffroy  St.  Hilaire's  investigations  in  his 
work  on  "  Monstruosites  Humaines;"  Meckel's 
Handbuch  der  Pathol ogischen  Anatomie,  Bd.  ii. 
s.  138;  and  a  paper  on  the  diseases  of  the  placenta, 
by  Dr.  Simpson,  in  the  Edin.  Med.  and  Surg. 
Journ.  vol.  xlv.  p.  305  et  seq. 

t  Dr.  Hildebrand  of  Berlin  has  also  noticed  my 
cases  with  some  remarks  :  see  Gr'afe,  und  Walthers 
Journal  der  Chirurgie,  Bd.  18,  11,  p.  325  :  1832. 
The  latest  author  on  the  subject  is  Graetzer,  die 
Krankheiten  des  fcetus,  Breslau,  1837,  p.  69. 

}  Memoirs  of  the  Imperial  Academy  of  Sciences 
of  St.  Petersburgh  for  1834,  sixth  series,  vol.  iii. 
p.  3,  7. 

§  Bulletins  de  la  Faculte,  &c.  for  1817,  torn.  v. 
p.  213. 


FCETUS. 


329 


Fig.  159. 


Albert  F.  Veiel  quotes  a  case  from  Froriep's 
Notizen,  Bd.  xii.  p.  26,  of  a  fetus  "  whose  left 
foot  was  separated,  during  pregnancy,  from 
the  bone,  and  the  fore  foot  was  born  by  itself, 
quite  healed."* 

The  following  case  was  recently  published  in 
the  American  Journal  of  Medical  Science,  by 
Dr.  F.  P.  Fitch  of  New  Boston.  On  the  17th 
March  a  healthy  woman,  then  in  the  seventh 
month  of  pregnancy,  suddenly  discharged  the 
liquor  amnii.  On  the  21st  a  substance  escaped 
from  the  vagina,  which  proved  to  be  a  perfectly 
well-formed  fcetal  foot,  apparently  separated  at 
the  ankle-joint,  and  in  a  complete  state  of  pre- 
servation. On  the  5th  April  she  was  delivered 
of  a  seven-months'  child,  which  lived  about 
half  an  hour.  At  the  left  side  of  the  centre  of 
the  forehead  there  was  a  horny  protuberance  of 
the  size  of  the  middle  finger ;  the  face,  also, 
was  greatly  deformed.  Upon  the  foot,  the 
place  of  separation  was  contracted  to  the  size 
of  a  small  pin's  head,  and  the  healing  process 
had  apparently  been  as  perfect,  and  progressed 
very  nearly  as  far  as  that  on  the  lower  extre- 
mity of  the  limb.^ 

Within  the  last  few  months  a  child  of  a 
month  old  was  brought  to  me  from  the  county 
of  Westmeath,  in  consequence  of  its  having 
been  born  deprived  of  the  left  hand.  On  exa- 
mination I  found  the  forearm  of  that  side  pre- 
senting, a  little  above  the  wrist,  the  appearance 
of  a  perfectly  well-formed  stump,  as  it  would 
be  found  after  amputation  by  the  surgeon's 
knife;  with  this  difference,  however,  that  the 
mark  of  cicatrix  did  not  extend  across  the 
stump,  but  was  confined  to  a  small  circular 

*  "  Der  linke  Fuss  wahrend  der  Schwangerschaft 
sich  von  dem  Beine  ablbste,  und  der  Vorderfuss 
f'tir  sich,  bereits  geheilt,  geboren  wurde." 

t  American  Journal  of  the.  Medical  Sciences, 
No.  xxxv.  for  May  1836,  p.  90. 


depression  in  its  centre;  the  child  was  other- 
wise quite  perfect  and  healthy.  Unfortunately 
I  could  not  obtain  any  information  as  to  whe- 
ther the  hand  had  been  found  at  the  time  of 
delivery  or  not,  the  poor  woman  having  been 
attended  only  by  an  ignorant  country  midwife. 
Three  cases,  very  similar  to  the  above,  are  de- 
scribed by  Dr,  Simpson.* 

I  feel  almost  convinced  that  the  removal  of 
limbs  in  this  way  is  by  no  means  so  uncommon 
an  occurrence  as  the  paucity  of  cases  hitherto 
recorded  would,  at  first  sight,  lead  us  to  con- 
clude ;  but  the  reason  appears  to  me  to  be  this, 
when  the  separated  portion  of  limb  was  not 
accidentally  discovered,  the  imperfection  seems 
to  have  been  considered  quite  as  a  matter  of 
course,  and  without  further  examination,  as 
arising  from  imperfect  development  or  monstro- 
sity, and,  consequently,  no  search  was  made 
for  the  deficient  part ;  and,  even  if  search  was 
made,  the  amputated  member  might  have  been 
so  small  as  to  escape  undiscovered,  involved  in 
the  membranes,  or  buried  in  coagula ;  even 
though  the  child  to  which  it  belonged  had  at- 
tained considerable  size,  because  its  separation 
may,  as  we  have  seen,  take  place  a  consider- 
able time  previous  to  birth ;  this  is  noticed  in 
Mr.  Watkinson's  case,  and  is  still  more  stri- 
kingly exemplified  in  that  described  by  Zagors- 
ky,  see  fig.  159. 

With  regard  to  the  theories  which  have  been 
advanced  to  account  for  such  accidents  as  that 
which  we  have  been  considering,  some,  regard- 
ing them  as  the  effects  of  mental  emotions  in 
the  mother,  or  of  accidents  encountered  by 
her,  have  attempted  to  support  their  views  by- 
details  which  Haller  truly  designates  as  "  adeo 
fabulosa  ut  fidem  auferant;"  those  who  attri- 
buted this  phenomenon  to  gangrene  did  so 
from  theory,  and  have  received  no  support  for 
their  opinions  even  from  the  facts  which  they 
have  themselves  recorded;  for  it  is  expressly 
mentioned  that  the  parts  which  were  the  seat 
of  the  injury  seemed  otherwise  healthy,  were 
not  discoloured,  and  at  the  point  of  division 
were  either  partially  or  entirely  healed  over. 
The  explanation  which  facts  fortunately  enabled 
me  to  offer  does  not  depend  on  conjectural 
reasoning  or  theoretical  speculation  for  its 
support,  but  its  proof  may  be  "  oculis  subjects 
fidelibus"  by  the  mere  inspection  of  the  parts, 
which  are  preserved  in  my  museum  ;  and  with 
regard  to  the  nature  of  the  process  by  which 
the  solution  of  continuity  is  effected,  and  the 
foot,  or  other  part  amputated,  it  appears  to  be 
strictly  that  of  disjunctive  atrophy,  and  in  a 
great  degree  similar  to  that  by  which  the  sepa- 
ration of  the  funis  from  the  umbilicus  is  accom- 
plished. 

Convulsive  affections. —  Having  alluded  to 
convulsive  movements  of  the  child  in  another 
place  as  the  occasional  cause  of  certain  phy- 
sical injuries  to  it,  such  as  fractures  and  dislo- 
cations, a  few  words  on  the  subject  will  hardly 
be  misplaced  here,  although  the  affection  itself 
may  perhaps  not  come  exactly  within  the  scope 
of  this  article.    The  variety  in  the  activity  of 

*  Dublin  Medical  Journal,  vol.  x.  p.  226. 


330 


FCETUS. 


foetal  motion  is  a  matter  of  common  observa- 
tion, for,  while  some  women  suffer  much  and 
almost  constant  annoyance  from  the  excessive 
restlessness  of  the  child,  others  are  hardly  con- 
scious of  its  movements.*  That  this  is  not 
altogether  dependent  on  a  real  difference  in  the 
quality  of  the  foetal  motions,  but  in  a  great 
degree  the  result  of  the  greater  or  less  nervous 
irritability  of  the  mother's  system,  must  be  ac- 
knowledged ;  but,  on  the  other  hand,  I  think 
we  can  hardly  doubt  that  some  of  those  pa- 
roxysms of  excessive  turbulence  are  true  con- 
vulsions, and  that  the  child  sometimes  thus 
dies  before  birth,  either  under  their  influence 
or  by  so  entangling  the  cord  as  to  compress 
it,  and  put  an  end  to  the  circulation  through 
it.  The  writer  feels  persuaded  that  he  has  met 
with  such  cases,  and  he  has  read  of  others  in 
which,  after  a  violent  convulsive  motion  of  this 
kind,  which  had  nearly  caused  the  mother  to 
faint,  all  motion  of  the  child  has  ceased  to  be 
felt,  and,  after  the  lapse  of  a  few  days,  delivery 
has  taken  place,  and  the  dead-born  child  has 
exhibited  appearances  perfectly  corresponding 
with  the  belief  of  its  having  died  at  the  time  of 
the  convulsive  struggle.  In  October  1834  the 
writer  attended  a  very  nervous  lady  with  her 
second  child,  which,  after  about  two  hours  of 
easy  labour,  was  born  completely  dead,  al- 
though full-sized  and  well  thriven ;  the  cord 
was  twisted  round  the  neck  and  also  round  one 
of  the  arms.  She  told  me  that  three  days 
before  she  was  suddenly  startled  by  the  exces- 
sive motion  of  the  child  "as  if  it  was  struggling 
in  convulsions;"  this  continued  for  a  minute 
or  two,  and  was  so  violent  and  distressing  as 
to  force  her  to  exclaim,  and  nearly  to  produce 
fainting ;  from  that  moment  she  never  felt  the 
child  move.f 

Effects  of  mental  impressions  on  the  mother. 
— In  the  enumeration  of  the  different  causes 
or  sources  of  abnormal  alterations  in  the  foetus 
we  should  not  omit  to  include  powerful  im- 
pressions made  on  the  mind  or  nervous  system 
of  the  mother ;  for  although  the  writer  would 
be  very  far  from  wishing  to  advocate  or  coun- 
tenance either  the  indiscriminate  doctrine  of 
effects  produced  by  the  mother's  imagination, 
or  the  ridiculously  absurd  fabrications  by  which 
it  has  been  attempted  to  maintain  it,  he  cannot 
help  thinking  it  quite  consistent  with  reason 
and  the  present  state  of  our  knowledge,  to  be- 
lieve that  such  impressions  may  injuriously 
affect  the  foetus,  and  it  will  at  least  be  always 
safe  and  prudent  to  act  on  such  a  presump- 
tion ;  for  "  although,"  to  use  the  words  of 
Morgagni,f  "  I  do  not  approve  these  things, 

*  See  some  observations  on  this  subject  in  the 
writer's  Exposition  of  the  Signs  of  Pregnancy, 
chapter  v.  p.  87. 

t  See  Desormeaux,  Diet.  Ide  Med.  torn.  xv. 
p.  398.  Duges,  Diet.  <le  Med.  et  de  Chir.  Pra- 
tique, torn.  viii.  p.  295.  A  slight  spasmodic  sen- 
sation communicated  from  the  child  to  the  mo- 
ther, and  sometimes  repeated  several  times  at 
pretty  regular  intervals,  like  the  efforts  of  hiccup, 
has  been  by  some  attributed  to  the  existence  of 
that  affection  in  the  child ;  but  with  what  degree 
of  reason  the  writer  is  not  prepared  to  venture  an 
opinion. 

}  Epist.  xlviii.  art.  54. 


(that  is,  the  absurd  stories,)  there  are  cases 
wherein  it  seems  to  me  to  be  very  hard  to 
depart  totally  and  altogether  from  that  opinion 
which  is  common  to  the  greatest  men."*  In  a 
case  related  by  this  celebrated  writer,  a  mental 
impression  was  quickly  followed  by  the  death  of 
the  child;!  and  if  such  an  influence  can  thus 
destroy  its  life,  it  is  surely  not  unreasonable  to 
admit  that  it  may  have  the  power  of  modifying 
organization.];  An  instance  of  this  kind  oc- 
curred under  my  own  observation  about  three 
years  ago,  so  remarkable  that  I  trust  I  shall  be 
excused  if  I  think  it  presents  something  more 
than  a  mere  though  striking  coincidence. 

A  lady,  pregnant  for  the  first  time,  to  whom 
I  recommended  frequent  exercise  in  the  open 
air,  declined  going  out  as  often  as  was  thought 
necessary,  assigning  as  her  reason,  that  she  was 
afraid  of  seeing  a  man  whose  appearance  had 
greatly  shocked  and  disgusted  her;  he  used  to 
crawl  along  the  flag-way  on  his  hands  and 
knees,  with  his  feet  turned  up  behind  him, 
which  latter  were  malformed  and  imperfect, 
appearing  as  if  they  had  been  cut  off  at  the 
instep,  and  he  exhibited  them  thus  and  unco- 
vered in  order  to  excite  commiseration.  I  af- 
terwards attended  this  lady  in  her  lying-in,  and 
her  child,  which  was  born  a  month  before  its 
time,  and  lived  but  a  few  minutes,  although  in 
every  other  respect  perfect,  had  the  feet  mal- 
formed and  defective  precisely  in  the  same  way 
as  those  of  the  cripple  who  had  alarmed  her, 
and  whom  I  had  often  seen.  Now  here  was  an 
obvious  and  recognized  object  making  a  pow- 
erful impression  of  a  disagreeable  kind,  com- 
plained of  at  the  time,  and  followed  by  an 
effect  in  perfect  correspondence  with  the  pre- 
vious cause,  there  being  between  the  two  a 
similarity  so  perfect  that,  with  the  distinguished 
author  above  referred  to,  I  "  will  not  easily 
suppose  that  chance  could  have  been  so  inge- 
nious, if  I  may  be  allowed  to  speak  thus,  and 
so  exact  an  imitator  ;"§  and  though  I  must  ac- 
knowledge in  the  words  of  Van  Swieten  "  that 
I  do  not  understand  the  connexion  of  the  cause 
acting  upon  the  mother  with  the  effect  observed 
in  the  foetus,"  ||  I  also  agree  with  him,  that  it 
must  not  therefore  be  denied  that  such  a  thing 
has  really  happened.  For  some  other  observa- 
tions on  this  subject  the  writer  begs  to  refer  to 
a  work^f  of  his  recently  published. 

Effects  of  inflammation,  SfC. — The  fcetus  in 
utero,  even  at  early  periods  of  its  developement, 
is  liable  to  a  large  number  of  organic  altera- 
tions, and  even  to  lose  its  life,  in  consequence 
of  inflammation  attacking  the  uterus  of  the 
mother,  the  foetal  appendages,  or  its  own  sys- 
tem.   From  such  causes  arise  a  variety  of  pa- 

*  He  refers  to  Boerhaave,  Praelect.  ad  Instit. 
§  694,  and  to  Van  Swieten. 
t  Epist.  xlviii.  art.  18. 

}  A  celebrated  writer  of  the  present  day,  Es- 
quirol,  is  led  from  observation  and  experience  to 
refer  one  of  the  species  of  congenital  predisposi- 
tion to  insanity,  to  the  impression  of  terror  on  the 
mind  of  the  mother  while  pregnant. 

§  Epist.  xlviii.  art.  54.   Vide  epist.  lxvii.  art.  16. 

||  Commentaries,  sect.  1075. 

%  An  Exposition  of  the  Signs  and  Symptoms  of 
Pregnancy,  chap.  i.  pp.  14  et  seq. 


FCETUS. 


331 


thological  changes  in  the  foetus,  as  atrophy,  small  intestines  presented  several  patches  of 
arrest  of  developement,  amputation  of  limbs,  ulceration,  and  the  coats  so  thickened  that  their 
and  many  other  affections,  as  detailed  in  the  calibre  was  quite  effaced*  Desormeaux  thinks, 
different  sections  of  the  present  article.  and  apparently  with  good  reason,  that  several 
With  respect  to  those  which  seem  distinctly  of  the  strictures  and  obliterations  of  hollow 
referrible  to  inflammation  arising  in  the  foetal  canals,  such  as  closing  of  the  oesophagus,  intes- 
system  and  invading  particular  organs,  the  in-  tinal  canal,  anus,  urethra,  &c.  ought  to  be  re- 
stances  are  very  numerous  indeed;  especially  ferred  to  the  influence  of  former  inflammation, 
in  the  thoracic  and  abdominal  cavities,  in  which  to  which  cause  also  there  is  great  reason  to 
striking  indications  of  violent  inflammatory  ac-  ascribe  many  instances  of  congenital  blindness, 
tion  have  been  frequently  observed,  both  by  and  especially  those  in  which  there  is  opacity 
the  writer  and  by  others.  of  the  cornea. 

During  the  investigations  made  conjointly  The  liver  is  not  unfrequently  the  seat  of  in- 
by  Madame  Boivin  and  M.  Chaussier,  they  flammatory  and  other  lesions  before  birth,  a 
met  with  several  cases  of  well-marked  perito-  variety  of  which  have  been  noticed  by  different 
nitis,  some  of  which  were  accompanied  by  con-  writers  ;  intense  sanguineous  congestion  has 
siderable  effusion,  which,  however,  did  not  exist  been  often  met  with.    Billard  mentions  two 
in  others ;  but  in  all  there  were  found  nume-  instances  in  which  the  organ  was  found  soft- 
rous  adhesions  between  the  intestines*  Desor-  ened  and  giving  out  an  odour  of  sulphuretted 
meaux  records  a  case  in  which  a  child  at  birth  hydrogen.    It  has  also  been  found  with  tuber- 
displayed  all  the  evidences  of  violent  enteritis,-)-  cles  scattered  through  its  substance  at  birth.-f 
but  afterwards  recovered.    In  a  case  related  by  Hoogeveen  describes  a  tumour  which  was  found 
Duges,  all  the  abdominal  viscera  were  found  attached  to  the  liver  of  a  foetus  of  six  and  a 
agglutinated  by  a  yellow  coloured  and  firm  half  months  :  it  was  hard  and  unequal,  and  as 
lymph;  there  were  false  membranes  on  the  if  composed  of  particles  of  soft  stone  or  cherry 
liver,  the  spleen,  the  bladder,  &c;  the  epiploon  kernels. %    Considerable  serous  effusion  in  the 
was  adherent  to  the  intestines,  which  were  ag-  abdominal  cavity  has  been  often  observed, 
glutinated  into  a  lump,  and  were  yellow,  hard,  The  organs  contained  in  the  thoracic  cavity 
and  thick. J  Other  instances  of  this  form  of  in-  appear  to  be  peculiarly  liable  to  the  invasion 
flammation  are  detailed  by  Billard,§  Carus,||  of  inflammatory  action,  and  frequently  exhi- 
Cruveilhier,H  and  others.  bit  other  abnormal  conditions  also.  Cruveil- 
The  stomach  and  intestinal  canal  have  fre-  hier  goes  so  far  as  to  say,  that  lesions  of  the 
quently  been  found  much  diseased  at  birth,  lungs  are  so  frequent  in  the  foetus,  that  in  his 
In  one  instance  of  a  still-born  child  I  found  opinion  disease  of  the  lungs  carries  off  as  many 
the  stomach  in  a  state  of  intense  inflammation,  new-born  children  as  adults. § 
and  on  its  internal  surface  there  were  no  less  The  lungs  have  been  found  hepatized  in 
than  twenty-five  patches  of  ulceration.    Dr.  C.  still-born  children,  two  instances  of  which  oc- 
Johnson  of  this  city  found  a  similar  condition  curred  to  AndraT,||  who  says  he  found  in  ano- 
existing  in  the  colon  :  the  specimen  is  depo-  ther  case  numerous  abscesses  in  one  lung, 
sited  in  the  Museum  of  the  College  of  Sur-  M.  Husson  examined  two  children,  one  of 
geons,  Dublin.    Cases  of  this  kind  are  also  de-  which  was  dead-born  in  the  seventh  month, 
scribed  by  Billard,**  who  mentions  an  instance  and  had  tubercles  softened  and  in  a  state  of 
in  which  he  found  in  the  duodenum  a  pedicu-  suppuration  in  the  lungs,  the  mother  being 
lated  excrescence  of  a  red  colour  and  uneven  healthy.    I  have  met  with  instances  of  tuber- 
like a  strawberry;  it  was  as  large  as  a  bean,  cles  in  the  lungs  at  birth,  but  in  the  cases 
and  in  its  structure,  &c.  resembled  the  vascular  which  came  under  my  observation,  the  mothers 
tumours  found  in  the  intestines  of  adults.    In  were  affected  with  consumption  ;  under  which 
the  same  child  there  was  also  evidence  of  circumstances  I   have,   in  several  instances, 
chronic  inflammation  of  the  lower  portion  of  found  in  the  placenta  a  deposit  of  what  appeared 
the  ilium,  with  thickening  of  the  mucous  mem-  to  be  perfect  tubercular  matter, 
brane,  which  was  of  a  slate  colour.ff    In  ano-  Cruveilhierlf  has  noticed  instances  of  tuber- 
ther  case  examined  by  the  same  writer,  the  c'ular  induration,  grey  consolidation,  scattered 
ilium  and  all  the  colon  were  found  presenting  masses  of  tubercular  character  containing  pus, 
the  characters  of  the  disease  named  by  Laennec  and,  in  one  case,  there  was  serous  infiltration 
sclerosis,  and  consisting  in  a  scirrhous  indura-  of  the  pulmonary  tissue,  which  was  of  an  olive 
tion  of  the  submucous  cellular  tissue  of  the  in-  green  colour.   Billard  **  relates  similar  cases  of 
testine.    In  a  case  observed  by  Cruveilhier  the  pulmonary  lesion,  as  does  also  Lobstein,-t/t  who 


*  Recherches  sur  l'Avortement,  &c.  p.  56,  note  ; 
see  also  Bulletin  de  la  Fac.  de  Med.  1821,  and 
Proces  verbal  de  la  Maternite,  Jan.  1812. 

t  Diet,  de  Med.  art.  CEuf,  torn.  xv.  p.  403. 

t  Recherches  sur  les  Maladies  les  plus  impor- 
tantes  et  les  moins  connues  des  enfans  nouveaux- 
nes,  par  Ant.  Duges,  D.M.    Paris,  1821. 

4  Maladies  des  Knfans,  p.  444. 

|  Gynaekologia,  ii.  p.  251. 

II  Livraison  xv.  pi.  xi.  p.  2,  ob.  2. 

**  Op.  jam  cit.  p.  296  et  seq.  Atlas,  pi.  v.  and 
also  p.  372. 

tt  Ibid.  p.  373,  4. 


•  Anat.  Pathol,  liv.  xv.  pi.  ii.  p.  4,  ob.  7. 

t  See  Billard  ut  supra,  p.  421,  and  Meissner, 
Kinderkrankhciten,  i.  s.  p.  92. 

t  Tract  de  Morb.  foetus  humani,  p.  63-,  see  also 
Bonetus,  Sepulch.  Anat.  torn.  iii.  p.  104,  Orlila, 
Lecjons  de  Med.  Leg.  Paris,  1828,  i.  p.  292,  and 
Andral's  Pathol.  Anat.  translated  by  Townseud 
and  West,  vol.  ii.  p.  704. 

4  Liv.  xv.  pi.  xi.  p.  5. 

\\  Op.  jam  cit.  p.  703. 

if  Op.  jam  cit.  liv.  xv.  pi.  xi.  pp.  4,6. 

**  Maiad.  des  Enfans,  pp.  499,  648. 

ft  Pathologischen  Anatomie,  i.  p.  321. 


332 


FCETUS. 


found  in  the  festal  lungs  a  calcareous  concre- 
tion. 

Pleuritis. — The  effects  of  inflammation  at- 
tacking the  pleura  before  birth  are  not  unfre- 
quently  seen.  Billard  relates  the  case  of  a 
child  which  died  on  the  fourth  day  after  birth, 
in  whom  the  pleura  was  found  greatly  thick- 
ened, and  there  were  existing  between  its  oppo- 
site surfaces  bands  of  adhesion  as  firmly  orga- 
nized as  those  found  in  an  adult,  eight  or  ten 
years  after  a  pleurisy.* 

In  a  case  described  by  Cruveilhier,  the  child 
died  thirty-six  hours  after  birth,  and  there  was 
found  double  pleurisy  with  effusion  of  a  sero- 
lactescent  pseudo-membranous  fluid ;  and  in 
another  instance  described  by  the  same  writer, 
in  addition  to  anasarca,  ascites,  and  purpura, 
there  existed  hydrothorax,  in  a  seven  months' 
child,  which  had  lived  only  twelve  hours  :f 
other  instances  are  related  by  Veron,  Orfila, 
and  others. 

Purulent  effusion.— The  formation  of  pus 
has  been  frequently  observed  in  the  foetus,  both 
in  the  form  of  secretion  from  the  lining  mem- 
branes of  cavities,  and  in  distinct  circumscribed 
abscesses. 

In  cases  of  pleuritis  and  peritonitis,  as  alrea- 
dy noticed,];  the  abdominal  and  thoracic  cavi- 
ties have  contained  sero-purulent  fluid.  Cru- 
veilhier found  pus  between  the  dura  mater  and 
skull  in  a  still-born  child.§ 

Abscesses  have  been  found  in  the  thymus 
and  thyroid  glands  and  in  the  supra-renal  cap- 
sules, see  p.  334 ;  and  Andral  found  several  in 
one  lung. || 

Ollivier  (d'Angers)  has  given  an  account  of 
the  examination  of  a  foetus  of  three  months  and 
a  half,  under  the  skin  of  whose  neck  an  abscess 
was  found.lf 

I  have  very  often  seen  small  superficial  ab- 
scesses or  pustules  existing  at  birth,  especially 
about  the  neck,  face,  and  head. 

Dropsical  effusions. — Several  forms  of  serous 
effusion  have  been  already  mentioned  as  taking 
place  during  foetal  life,  and  affecting  either  the 
cellular  tissue,  the  great  cavities  of  the  abdo- 
men and  thorax,  those  of  the  brain,  or  confined 
to  particular  organs  and  their  appendages. 

Thus  notice  has  been  taken  of  the  occurrence 
of  general  anasarca,  ascites,  hydrothorax,  hydrops 
pericardii,  serous  infiltration  of  the  lung,  hydro- 
cephalus, and  hydro-rachitis  or  spina  bifida'. 
In  one  instance  which  I  examined  some  years 
since  there  was  general  anasarca  and  serous 
effusion  into  every  one  of  the  cavities;  the  mo- 
ther was  healthy,  but  was  in  the  habit  of  drink- 
ing enormous  quantities  of  ardent  spirits. 

The  degree  to  which  the  head  sometimes  be- 
comes enlarged  in  uteroby  dropsy  is  as  extraor- 
dinary as  it  is  well  known,  and  the  difficulty  of 
delivery  thus  produced  is  equally  a  matter  of 
frequent  observation  with  practitioners  in  mid- 

*  Op.jamcit.  p.  501. 

t  Anat.  Pathol,  liv.  xv.  pi.  xi.  p.  2,  obs.  4. 
\  See  Billard,  Malad.  des  Enfans,  p.  445. 
§  Liv.  xv.  pi.  xi.  p.  6,  obs.  10. 
||  Anat.  Pathol,  by  Townsend  and  West,  vol.  ii. 
p.  703. 

H"  Arch.  Gen.  de  Med.  Mai  1834. 


wifery.  In  one  specimen  in  my  possession,  the 
long  diameter  of  the  head  is  six  inches,  the  trans- 
versefive and  five-eighths,and  the  circumference 
nineteen  inches  :  this  case  gave  rise  to  the  ne- 
cessity of  performing  cephalotomy.  In  another 
instance  of  twins  I  was  called  in,  in  conse- 
quence of  delivery  of  the  first  child  being  found 
impracticable,  the  head  being  firmly  retained 
after  the  expulsion  of  the  rest  of  the  body.  I 
succeeded  in  extricating  it,  without  perforation 
or  instruments  of  any  kind ;  it  measured  eight- 
een inches  and  a  half  in  circumference.*  In  a 
case  related  by  Perfect,f  the  head,  when  extri- 
cated from  the  pelvis,  measured  more  than 
twenty-four  inches  in  circumference.  In  an 
instance  of  an  hydrocephalic  twin,  described  by 
Dr.  Patterson,]  tne  circumference  of  the  head 
was  nearly  twenty-one  inches. 

Cases  have  also  occurred  in  which  enlarge- 
ment of  the  foetal  belly  from  ascites  has  been 
sufficient  to  impede  delivery  ;  no  such  case  has 
come  under  the  writer's  observation,  but  others 
have  met  with  them.§  In  another  section  of 
this  article  a  case  is  noticed,  in  which  immense 
distension  of  the  foetal  bladder  produced  great 
difficulty  in  effecting  the  delivery.  See  p.  335. 
In  such  cases  hydrocele  has  been  sometimes 
observed  at  birth,  and  in  other  instances  also.|| 

Ollivier  (d'Angers)  has  described  a  case  of 
dropsy  confined  to  the  cavity  of  the  great  epi- 
ploon in  a  well-formed  child  dead-born  at  the 
eighth  month  :  the  lamina  of  the  peritoneum 
were  separated  by  a  serous  fluid  of  a  yellow 
colour,  and  perfectly  limpid,  in  which  were 
floating  flakes  of  albumen  :  the  posterior  layer 
of  the  epiploon  was  slightly  opaque.  The 
tumour  distended  the  abdomen  enormously, 
and  there  was  fluctuation  as  in  ascites  :  there 
were  present  all  the  characters  of  circumscribed 
inflammation  of  the  epiploon.1T 

Induration  of  the  cellular  tissue. — This  pe- 
culiar affection,  in  the  great  majority  of 
instances,  does  not  invade  the  system  for  some 
days  after  birth,  and  even  then  it  is  of  rare 
occurrence.  My  experience  has  not  afforded 
me  an  opportunity  of  examining  more  than 
two  cases,  which  were  not  congenital. 

It  has  been  already  described  in  this  work 
(see  Cellular  Tissue,  p.  516),  and  it  ap- 
pears only  necessary  to  add  here  that  the 
affection  is  sometimes  found  fully  established 
at  birth.  "  Many  children,"  says  Andral,** 
"  come  into  the  world  with  this  affection,"  and 
we  have  the  testimony  of  Billardf  f  and  others 
to  the  same  effect.  Jaundice  has  been  more 
frequently  found  than  any  other  affection  in 

*  An  accurate  cast  of  it  is  preserved  in  the  wri- 
ter's museum. 

t  Cases  in  Midwifery,  toI.  ii.  p.  525. 

X  Lond.  Med.  and  Surg.  Joiirn.  Sept.  17,  1836, 
p.  86. 

§  See  Gardien,  Traite  complet  d'Accouchemens, 
torn.  iii.  p.  106 ;  Duges,  Diet,  de  Med.  et  de  Chir. 
Pratique,  torn.  viii.  p.  303. 

||  Graetzer,  Die  Krankheiteu  des  Foetus,  p.  159  ; 
Billard,  Malad.  des  Enfans,  p.  630. 

%  Archives  Generates  de  Med.  Mai  1834. 

**  Anat.  Pathol,  by  Townsend  and  West,  vol.  ii. 
p.  580. 

ft  Malad.  des  Enfans,  p.  178. 


FCETUS. 


833 


conjunction  with  this  oedema  of  the  cellular 
tissue.  Of  seventy-seven  cases  examined  by 
Billard,  thirty  were  affected  with  jaundice.* 

For  a  very  full  account  of  this  subject  see 
Graetzer,  die  Krankheiten  des  Foetus  :  section 
scleroderma. 

Cutaneous  affections. — Lesions  of  the  skin 
are  probably  the  most  numerous  class  of  affec- 
tions to  which  the  foetus  in  utero  is  liable. 

Some  of  these  appear  to  be  in  a  great  mea- 
sure mechanically  produced  in  consequence 
of  the  occurrence  of  other  diseases,  as  in  cases 
of  spina  bifida,  encephalocele,  and  other  tu- 
mours of  the  head.  In  these  instances  the 
skin  covering  the  tumour  is  first  attenuated 
as  it  is  distended,  and  subsequently  it  disap- 
pears altogether,  and  not  unfrequently  becomes 
ulcerated.  In  some  instances  the  injury 
observed  on  the  skin  is  the  result  of  inflamma- 
tion either  attacking  the  skin  itself  or  the  mem- 
branes of  theovum;  in  the  former  case  abscesses 
may  form  and  ulceration  be  produced.  I  have 
frequently  seen  instances  of  both,  and  also 
very  distinct  cicatrices,  which  must  have  been 
a  considerable  time  in  existence.  Ollivier 
(d'Angers)  describes  a  remarkable  case  of  ulce- 
ration on  the  legs  of  a  child  born  with  clubbed 
feet.f  I  have  more  than  one  instance  in  my 
museum  of  destruction  of  the  skin  from  adhe- 
sion having  taken  place  between  the  foetus  and 
the  membranes.  Excrescences  from  the  skin 
have  been  observed  by  the  last-named  author, 
Billard,!  and  others.  The  writer  once  attended 
a  lady  who  gave  birth  to  a  very  fine  healthy 
child  with  two  excrescences  attached  by  pe- 
dicles over  the  third  phalanx  of  each  little 
finger.  Naevi  of  different  kinds  existing  at 
birth  are  matters  of  common  observation,  and 
in  not  a  few  instances  petechia;  have  been 
observed  in  the  form  usually  denominated  pur- 
pura haemorrhagica.§ 

Very  many  instances  of  the  eruptive  diseases 
have  been  noticed  in  the  immature  foetus  and 
child  at  birth.  Vogel  and  Rosen  mention  in- 
stances of  chilbren  born  with  the  traces  of 
measles,  and  Guersent  says  ||  he  saw  an  infant 
born  with  the  eruption  on  it,  having  taken  the 
disease  from  the  mother. 

In  the  course  of  the  last  year  I  attended  a 
patient  who  was  delivered  a  month  before  her 
time,  when  just  recovering  from  an  attack  of 
scarlatina ;  the  child's  skin  exhibited  the  erup- 
tion in  several  places  :  it  recovered. 

*  Ibid,  p.  179.  See  also  Deutschberg,  Dissert, 
de  tumor,  nonnul.  congenitis,  Vratislav,  1822,  p.  21; 
and  Abbild.  t.  ii.  Leger,  Considerations  sur  l'in- 
durcissement  du  tissu  cellulaire  chez  les  nouveaux- 
nes.  Denis,  Theses  de  Paris,  n.  159,  annee  1824, 
de  l'indurcissement  du  tissu  cellulaire,  &c.  and 
Recherches  d'Anat.  et  de  Physiol.  Pathol,  sur  plu- 
sieurs  Maladies  des  Enfans  nouveaux-nes,  Paris, 
1826,  p.  145.  Orfila,  Lecons  de  Med.  Leg.  p.  375. 
Alibert,  Nosol.  Naturelle,  p.  495-499. 

+  Arch.  Gen.  de  Med.  Mai  1834. 

t  Maladies  des  Enfans,  p.  79. 

$  See  Billard,  op.  jam  cit.  p.  92,  3.  Graetzer, 
p.  60.  Cruveilhier,  liv.  xv.  pi.  ii.  p.  2,  3,  obs. 
4  and  5. 

||  Diet,  de  Med.  t.  xviii.  p.  513.  For  several 
other  references  see  Graetzer,  die  Krankheiten 
des  Foetus,  p.  46. 


Small-pox  has  been  observed  on  the  child  at 
birth  and  under  remarkable  circumstances,  as 
in  cases  where  the  mother  had  not  been  affected 
with  the  disease  during  gestation.  See  cases 
by  Jenner,  Med.  Chir.  Trans,  vol.  i.  p.  269 ; 
and  a  very  remarkable  one  by  Mead,  in  which 
"  a  certain  woman  who  had  formerly  had  the 
small-pox,  and  was  now  near  her  reckoning, 
attended  her  husband  in  the  distemper.  She 
went  her  full  time  and  was  delivered  of  a  dead 
child.  It  may  be  needless  to  observe  that  she 
did  not  catch  it  on  this  occasion,  but  the  dead 
body  of  the  infant  was  a  horrid  sight,  being 
all  over  covered  with  the  pustules;  a  manifest 
sign  that  it  died  of  the  disease  before  it  was 
brought  into  the  world."  Works,  edit.  1767, 
p.  253. 

Billard  *  mentions  having  seen  in  the  Museum 
of  Guy's  Hospital  a  foetus  of  six  months  covered 
with  pustules  of  small-pox,  which  was  born 
when  the  mother  was  just  recovering  from  the 
disease. 

"  Mary  Gatton  had  confluent  small-pox  in 
the  seventh  month  of  her  pregnancy  ;  eighteen 
days  from  the  first  attack  of  the  eruptive  fever 
she  was  taken  in  labour  and  delivered  of  a 
child,  which  seemed  to  have  been  dead  five  or 
six  days.  Its  body  was  covered  with  confluent 
small-pox.  The  pustules  were  white  and  full 
of  matter,  and  from  their  size  seemed  to  have 
nearly  attained  their  maturity  ."f 

"  A  lady  was  inoculated  in  the  seventh 
month  of  her  pregnancy,  and  on  the  ninth  day 
from  the  accession  of  the  eruption,  which  was 
moderate,  she  received  a  fall ;  from  that  period 
the  motions  of  the  child  were  no  longer  per- 
ceptible :  in  eight  days  after  she  was  taken  in 
labour,  and  delivered  of  a  dead  child  covered 
with  a  great  quantity  of  variolous  pustules, 
which  were  prominent  and  in  a  state  of  suppu- 
ration."! 

Pemphigus  has  been  observed  on  the  child 
at  birth  by  Lobstein,§  Joerg,||  and  others. 

When  the  system  of  either  parent  retains  a 
taint  of  syphilis,  the  child  very  frequently  exhi- 
bits at  the  time  of  birth  unequivocal  evidence 
of  being  contaminated  by  the  disease,  and 
sometimes  of  having  already  fallen  a  victim  to 
its  ravages ;  though  in  the  majority  of  such 
cases  the  children  are  born  alive,  often  appa- 
rently healthy,  and  do  not  exhibit  any  appear- 
ance of  disease  for  a  few  weeks. 

In  many  instances  children  so  tainted  are 
born  in  a  state  of  complete  putridity,  and  with 
the  skin  either  already  stripped  off  or  quite 
loose  and  detached ;  in  other  instances,  which 
are  much  more  rare,  the  children  have  been 
born  alive,  with  a  well-marked  syphilitic  erup- 

*  Op.  jam  cit.  p.  97.  See  also  Graetzer,  op. 
cit  p.  27. 

f  Paper  by  Dr.  Bland  in  Simmons'  Lond.  Med. 
Journ.  vol.  ii.  p.  204. 

X  Mem.  Lond.  Med.  Soc.  vol.  iv.  p.  364. 

§  Journ  Complem.  du  Diet,  des  Sci.  Med.  t.  vi. 
p.  1. 

||  Handbuch  der  Kinderkrank.  1826,  p.  310. 
See  also  Siebold,  Journal  fur  Geburtshulfe,  &c.  iv. 
Bd.  1,  St.  1823,  s.  17.  Meissner,  Kindcrkrank- 
heiten  1.  p.  406,  410.  Wichmann,  Beitrag  zur 
Kenntniss  von  Pemphigus,  p.  15. 


334 


FGiTUS. 


tion  on  the  skin,  as  in  the  cases  recorded  by 
Cruveilhier,*  Dr.  Collins,f  and  others.  I 
am  indebted  to  Dr.  Collins  for  a  very  accurate 
drawing  of  one  of  his  cases ;  the  skin  of  the 
child  generally  was  of  a  very  dark  hue ;  scat- 
tered over  different  parts  of  the  body  were 
brownish  or  copper-coloured  blotches,  inter- 
mingled with  pustules  and  with  large  vesicular 
patches  containing  a  straw-coloured  purulent 
fluid,  along  with  which  there  were  also  nume- 
rous superficial  ulcerations  of  a  bright  red 
colour. 

Affections  of  the  heart  and  pericardium. — 
Independently  of  the  innumerable  irregularities 
of  structure  and  malformation  to  which  the 
heart  is  liable,  experience  has  shewn  that  both 
it  and  its  pericardium  are  sometimes  attacked 
by  disease  in  utero. 

Denis  gives  an  account  of  a  case  of  hyper- 
trophy of  the  heart  at  birth.J  The  following- 
case  of  scirrhous  tumours  in  the  heart  is 
described  by  Billard.§  On  opening  the  body 
of  a  child  of  three  days  old  he  found  on  the 
anterior  surface  of  the  heart  along  the  inter- 
ventricular line  three  projections  of  a  whitish 
colour;  they  were  buried  in  the  substance  of 
the  wall  of  the  left  ventricle  and  the  inter- 
ventricular septum,  projecting  a  little  into  the 
cavity  of  the  organ.  When  cut  into,  they 
creaked  under  the  scalpel,  and  the  cut  surface 
exhibited  closely  interlaced  fibres,  perfectly 
resembling,  both  in  appearance  and  form,  those 
of  scirrhus.  Cruveilhier  details  a  highly 
interesting  case  of  aneurism  of  the  right  auricle 
and  ventricle  in  consequence  of  the  obliteration 
of  the  orifice  of  the  pulmonary  artery.  The 
child  was  born  at  eight  months  and  a  half  in  a 
state  of  extreme  debility,  and  lived  only  five 
days,  all  which  time  the  respiration  was  im- 
perfect, embarrassed,  and  almost  convulsive. 
On  examination  the  heart  was  found  enor- 
mously enlarged,  filling  more  than  half  the 
thorax,  and  pushing  back  the  lungs,  which  were 
of  small  size.  The  right  cavities  were  so  en- 
larged as  to  constitute  seven-eighths  of  the 
whole  organ ;  the  valve  of  the  right  auriculo- 
ventricular  opening  was  attached  and  fixed  in 
such  a  way  that  the  blood  passed  as  freely 
from  the  ventricle  into  the  auricle  as  in  the 
opposite  direction,  and  there  were  floating 
granulations  on  the  free  edge  of  the  valve. 
The  orifice  of  the  pulmonary  artery  was  com- 
pletely obliterated,  but  otherwise  the  artery 
and  its  divisions  were  healthy. ||  "  How  could 
life,"  asks  Cruveilhier,  "  be  maintained  for  five 

*  Anatomie  Pathol,  liv.  xv.  pi.  11,  p.  6,  obs. 

t  Practical  Treatise  on  Midwifery,  &c.  p.  508, 11. 
On  this  subject  see  Doublet,  Memoire  sur  la  Verole 
des  Enfans  nouveaux-nes,  Paris,  1781.  Dr.  Beatty, 
Trans.  Assoc.  Coll.  Phys.  in  Ireland,  vol.  iv.  p.  31. 
Haase,  de  Syphilidis  recens  natorum  pathogenia, 
Lipsia;,  1828.  J.  F.  H.  Albers,  Ueber  die  Er- 
kenntniss  und  fur  der  Syphilischen  Hautkrank- 
heiten,  1832.  Wendt,  Kinderkrankheiten  iii.  Aufl. 
p.  109.  Duges,  Diet,  de  Med.  et  de  Chir.  Pra- 
tique, vol.  viii.  p.  298.  Colles,  Practical  Obser- 
vations on  the  Venereal  Disease,  1837,  p.  262. 

}  Recherches  d'Anat.  et  de  Phys.  Pathol.  &c. 
des  Enfans,  p.  353,  Paris,  1826. 

4  Maladies  des  Enfans,  p.  647. 

]|  Anat.  Pathol,  liv.  xv.  pi.  ii.  p.  4,  obs.  8. 


days  ?  there  did  not  pass  a  drop  of  blood  into 
the  lungs  from  the  right  ventricle.  I  think 
that  the  entrance  of  the  blood  into  the  lungs 
was  partially  accomplished  through  the  ductus 
arteriosus ;  it  is  probable  that  life  would  have 
been  maintained  if  the  foramen  ovale  had 
remained  free  and  open."  It  appears  to  me 
that  the  explanation  here  offered  by  the  author 
is  probably  correct,  as  I  once  saw  an  instance 
in  which  a  child  affected  with  the  morbus 
coeruleus  lived  a  year  and  a  half,  and  on  exa- 
mination we  found  that  the  aperture  of  the 
pulmonary  artery  was  completely  obliterated 
where  it  should  have  joined  the  right  ventricle, 
but  the  aorta  had  an  opening  into  it  from  both 
ventricles,  and  the  ductus  arteriosus  was  quite 
open  and  free  ;  and  my  opinion  then  was  that  in 
this  way  sufficient  blood  was  transmitted  to  the 
lungs  and  revivified  for  the  imperfect  support  of 
life ;  the  foramen  ovale  was  open.  Billard  also 
met  with  an  instance  of  aneurism  of  the  ductus 
arteriosus  in  a  new-born  child :  the  heart  was 
larger  than  usual,  the  duct  was  of  the  form  of  a 
large  cherry-kernel  and  filled  with  fibrinous  co- 
agula  disposed  in  layers,  as  they  are  found  in 
the  aneurisms  of  adults.*  How  far  this  affection 
truly  deserves  the  name  of  aneurism  seems 
somewhat  doubtful ;  but  the  writer,  not  long 
since,  met  with  a  similar  condition  of  the 
ductus  arteriosus  when  examining  the  body  of 
an  infant  which  died  suddenly. 

Pericarditis.— Evidences  of  the  existence  of 
this  disease  have  also  been  frequently  met  with. 
In  a  child  only  two  days  old  Billard  found 
between  the  opposite  surfaces  of  the  pericar- 
dium adhesions  so  firm  as  to  lead  to  the  con- 
clusion that  they  must  have  been  formed  during 
fcetal  life;t  and  in  the  case  of  a  child  which 
lived  only  an  hour  Cruveilhier  found,  in  addi- 
tion to  anasarca,  ascites,  and  purpura,  effusion 
in  the  sac  of  the  pleura  and  a  great  quantity  of 
fluid  in  the  pericardium 4  Speaking  of  this 
affection,  Andral  says,  "  It  is  a  fact  which  one 
would  never  imagine,  a  priori,  that  irritation 
of  the  pericardium  terminating  in  the  formation 
of  false  membranes  or  purulent  effusion  into 
its  cavity  is  a  common  enough  disease  in  the 
foetus,  even  more  so,  perhaps,  than  in  the 
adult."§ 

The  thymus  gland. — Considering  the  num- 
ber of  pathological  lesions  to  which  we  have 
just  seen  that  the  lungs  are  liable,  although 
being  organs  in  a  state  of  complete  quiescence 
during  fcetal  life,  we  cannot  be  surprised  that 
the  thymus,  which  attains  so  great  a  degree  of 
development  (if  not  its  greatest)  before  birth, 
should  frequently  exhibit  evidences  of  morbid 
over-action,  and  accordingly  several  instances 
of  the  kind  have  been  recorded. 

Cruveilhier  relates  a  case  of  a  child  which 
lived  only  a  few  minutes,  and  under  whose 
sternum  there  was  a  large  collection  of  pus 
which  was  lodged  partly  in  the  thymus  and 
partly  in  the  anterior  mediastinum;  the  thymus 

*  Op.  jam  cit.  p.  567,  and  atlas  pi.  8. 
t  Ibid,  p.  571. 

X  Anat.  Pathol,  liv.  xv.  pi.  ii.  p.  3,  obs.  5. 
§  Pathol.  Anat.  by  Townsend  and  West,  vol.  ii. 
p.  "702,  3. 


FCETUS. 


335 


was  much  enlarged,  contained  eeveral  tuber- 
culated  cells  filled  with  pus.  He  considers  it 
a  tubercular  affection  of  the  thymus,  or  in 
other  words,  a  chronic  inflammation  of  that 
organ.* 

Veronf  found  the  thymus  at  birth  very  volu- 
minous, much  inflamed,  and  containing  a 
quantity  of  pus. 

The  thyroid  gland.— This  organ  has  been 
found  exhibiting  similar  lesions  to  those  just 
described,  instances  of  which  are  recorded  by 
Francus,}  Carus,§  Hufeland,||  and  others. 

Abnormal  conditions  of  the  fatal  bladder.— 
The  consideration  of  this  subject  necessarily  in- 
volves the  disputed  question,  whether  urine 
be  secreted  by  the  child  before  birth,  of  which, 
however,  the  writer  feels  fully  convinced  by 
facts  within  his  own  observation. 

In  the  year  1824  I  attended  a  patient  who 
was  delivered  of  a  still-born  child,  which  had 
an  unusual  prominence  of  the  lower  part  of  the 
abdomen ;  on  laying  my  hand  over  the  part,  I 
ascertained  the  existence  of  a  tumour  of  extra- 
ordinary firmness,  which,  on  opening,  I  found 
to  he  the  bladder,  distended  to  the  size  of  a 
large  orange,  remarkably  tense,  and  containing 
a  fluid  having  the  appearance  of  urine  :  it  was 
not,  however,  chemically  examined  ;  the  ure- 
ters were  so  distended  that  their  coats  were 
diaphanous,  the  diameter  of  those  canals  being 
nearly  an  inch,  and  they  were  very  much  con- 
voluted in  their  length,  which  greatly  exceeded 
what  is  usual :  the  pelves  of  the  kidneys  were 
in  a  similar  state  of  distension  ;  the  urethra, 
where  it  joined  the  bladder,  was  completely 
impervious. 

In  the  course  of  the  last  year  I  was  in 
attendance  on  a  lady  who  had  in  her  former 
labours  suffered  frightfully  from  hemorrhage 
coming  on  after  the  birth  of  the  child ;  as  a  means 
of  preventing  the  recurrence  of  so  dangerous 
an  accident,  I  conducted  the  delivery  with  the 
greatest  caution,  and  allowed  the  uterine  con- 
traction to  effect  the  expulsion  of  the  child, 
even  to  the  feet  :  but  while  it  was  lying  with 
the  legs  and  thighs  still  within  the  vagina,  the 
penis  became  partially  erected,  and  a  stream 
of  urine  was  expelled  in  an  arch,  to  the  amount 
of  at  least  six  or  seven  ounces. 

The  following  case,  related  by  Mr.  Fearn,1f 
is  a  striking  example  of  the  degree  to  which 
the  bladder  may  be  affected  before  birth.  After 
the  expulsion  of  the  child's  head,  the  extrac- 
tion of  the  body  was  found  impracticable,  even 
after  mutilation  of  the  upper  extremities,  and 
evisceration  of  the  thorax.  An  elastic  tumour 
was  now  felt  in  the  situation  of  the  diaphragm  ; 
this  was  punctured,  and  immediately  an  im- 
mense quantity  of  reddish  watery  fluid  escaped, 
and  the  delivery  was  easily  completed.  On 

*  Anat.  Pathol,  liv.  xv.  pi.  ii.  fig.  2. 

t  Mem.  dans  la  seance  de  l'Acad.  Royale  de 
Med.  26  Aout,  1825. 

X  Eph.  N.  C.  Dec.  11,  an.  v.  obs.  223. 

6  Leipz.  Lit.  Zeit..  1816,  p.  238;  1817,  p.  301  ; 
1819,  p.  452  ;  1820,  p.  241,  and  Gynsekologia  ii. 
p.  253. 

||  Journal,  1827,  Bd.  64,  p.  26. 

IT  See  Lancet,  vol.  ii.  for  1834-35,  p.  178. 


examination,  the  child  appeared  to  have  arrived 
at  the  seventh  or  eighth  month ;  the  parietes  of 
the  abdomen  were  large  and  flaccid,  and  in  its 
cavity  was  an  immense  sac,  the  coats  of  which 
were  three  or  four  lines  in  thickness,  and  tra- 
versed in  every  direction  by  numerous  large 
vessels  gorged  with  blood.  This  sac  was,  after 
careful  dissection,  distinctly  made  out  to  be 
the  urinary  bladder  which  had  been  enormously 
distended  by  the  secretion  from  the  kidneys  ;  its 
muscular  fibres  were  much  hypertrophied ;  it 
had  no  communication  with  the  urethra ;  the 
penis  was  well  developed,  but  the  urethra  passed 
down  along  it  only  as  far  as  its  membranous 
portion.  The  kidneys  were  flabby,  and  their 
secreting  and  tubular  portions  much  attenuated, 
owing  to  the  distension  the  pelvis  of  each  had 
undergone;  the  ureter  on  each  side,  when 
inflated,  was  nearly  an  inch  in  diameter,  and  at 
one  side  the  valvular  opening  into  the  bladder 
was  large  enough  to  admit  readily  the  point  of 
the  little  finger.  The  bladder  when  rilled  with 
water  contained  upwards  of  two  quarts.  The 
rectum  terminated  in  a  blind  pouch  in  the  pelvic 
cavity,  and  there  was,  consequently,  no  anal 
opening.*  There  was  besides  an  arrest  of  de- 
velopment of  the  right  lower  extremity,  the 
limb  becoming  suddenly  wasted  immediately 
below  the  knee,  and  having  attached  to  it  a 
foot  no  larger  than,  and  in  every  way  resem- 
bling that  of  an  embryo  of  the  tenth  or  twelfth 
week.  The  body  appeared  in  other  respects  to 
have  been  tolerably  well  nourished. 

In  a  case  mentioned  by  Dr.  Lee,-j-  which 
occurred  to  Mr.  Hay  of  Osnaburg-street,  the 
child's  abdomen  was  so  large  at  birth  in  the 
eighth  month  that  it  passed  with  difficulty 
through  the  pelvis,  and  the  enlargement  was 
found  to  arise  from  an  accumulation  of  fluid 
within  the  kidneys,  produced  by  an  impervious 
state  of  the  ureters.  The  right  kidney,  which 
resembled  a  thin  cyst  filled  with  a  watery  fluid, 
was  larger  than  the  head  of  the  child  ;  the  left 
did  not  exceed  half  this  bulk  ;  it  contained  four 
ounces,  and  the  other  nine,  of  a  fluid  resem- 
bling urine,  and  which,  when  examined  by  Dr. 
Prout,  was  found  to  contain  the  chemical  con- 
stituents of  that  fluid.  The  child  had  also  a 
double  hare-lip  and  clubbed  feet. 

Mr.  Howship  examined  the  body  of  a  child 
which  died  a  few  hours  after  birth  in  the  eighth 
month  ;  it  had  distorted  feet,  imperforate  anus, 
and  the  lower  part  of  the  abdomen  was  occupied 
by  a  large  circumscribed  tumour,  which  proved 
to  be  the  bladder,  the  coats  of  which  had  ac- 
quired a  very  extraordinary  degree  of  strength 
and  thickness  ;  the  ureters  were  thin  and  mem- 
branous from  distension  and  curiously  con- 
torted, and  terminated  in  what  appeared  like  a 
congeries  of  small  hydatids  no  larger  than  garden 
peas,  loosely  connected  together  by  a  cellular 
texture;  these  were  the  kidneys  in  a  morbid  state: 
the  urethra  was  impervious.  Mr.  Howship 
alludes  to  two  other  nearly  similar  cases. J 

*  The  writer  had  lately  an  opportunity  of  ex- 
amining a  specimen  of  this  peculiarity  in  Dr.  Mur- 
phy's collection. 

t  Med.  Chir.  Trans,  vol.  xix.  p.  238. 

%  Treatise  on  the  Urine,  &c.  1823,  p.  374,  6. 


336 


Other  instances  of  this  condition  of  the 
urinary  apparatus  are  recorded  by  other  writers,* 
and  in  particular  Meckel  has  related  a  case  in 
which  it  was  conjoined  with  several  other  very 
remarkable  deviations.f 

Urinary  deposits. — It  is  no  slight  confirma- 
tory proof  of  the  secretion  of  urine  by  the  foetus, 
that  urinary  deposits  have  been  discovered  in 
the  kidneys,  ureters,  and  bladder.  Brendelius 
mentions  two  cases,  in  one  of  which  a  child 
only  two  days  old,  and  in  the  other  one  of 
eight  days  old,  passed  calculi  before  death;  and 
calculi  were  also  found  in  their  bladders.  J 

Loeseke  found  a  calculus  in  the  kidney  of  a 
new-born  child.§  Hoffman  relates  the  case 
of  a  German  princess  who  was  afflicted  with 
renal  calculus,  and  gave  birth  to  a  daughter, 
who  from  the  hour  of  birth  suffered  excru- 
ciating pain  when  passing  water ;  the  child 
died  when  three  weeks  old,  and  on  examin- 
ing the  body  a  calculus  as  large  as  a  peach 
kernel  was  found  in  the  bladder.||  Orfila 
saw  two  cases  in  which  there  were  calculi  in 
the  bladder  and  in  the  kidneys  at  birth. If 

Premature  developcment  of  teeth.  —  It  is 
hardly  necessary  to  remark  that  at  an  early 
period  of  foetal  existence  the  teeth  begin  to  be 
developed,  and  it  is  equally  a  matter  of  com- 
mon observation  that  they  do  not  in  general 
emerge  from  their  alveoli  and  pass  through  the 
gums  until  several  months  afterbirth.  But  many 
instances  have  been  observed  in  which  some  of 
them  have  been  found  developed  and  projecting 
above  the  gums  at  birth. 

I  have  before  me  at  this  moment  four  teeth 
of  this  kind  taken  from  the  gums  of  the  only 
two  children  of  a  patient  of  mine ;  in  each 
child  the  two  middle  incisors  of  the  lower  jaw 
were  found  projecting  at  birth,  and  in  each 
instance  it  was  found  necessary  to  extract  them 
after  a  few  days,  in  consequence  of  their  cut- 
ting the  child's  tongue  and  preventing  it  from 
sucking. 

Louis  XIV.  and  Mirabeau  are  well-known 
instances  of  this  premature  developement  of 
teeth,  and  many  other  cases  are  recorded  by 
different  authors ;  for  several  references  see 
Graetzer.** 

This  abnormal  condition  of  the  teeth  has 
been  frequently  found  accompanying  certain 
deformities  of  the  face,  especially  hare-lip  and 
cleft  palate. 

Intestinal  worms. — However  repugnant  to 
our  ideas  of  probability  the  existence  of  worms 
in  the  intestines  of  the  foetus  in  utero  may  at 

*  See  Billard,  Maladies  dea  Enfans  Nouveaux- 
nes,  &c.  p.  431  et  seq.  ;  Ollivier  d'Angers.  Archiv. 
Gen.  de  Med.  t.  xv.  p.  371  ;  Mr.  Wilson,  Med. 
Chir.  Trans,  vol.  xix.  p.  248. ;  Ruysch,  Sandifort, 
Wrisberg,  Chaussier,  and  Vrolik  have  described 
such  cases. 

t  Journ.  Complem.  des  Sciences  Med.  t.  xiii. 
p.  335. 

%  Program,  de  Calcnl.  Vesic.  et  ceteris  Natal. ; 
also  Obs.  Anat.  Dec.  iii.  ob.  1. 

§  Obs.  Anat.  Chir.  Med.  p.  39. 

||  Dissert,  inaug.  de  morbis  foetus  in  utero  ma- 
terno,  Hals  Magdeb.  1702. 

1  Lecons  de  Med.  Leg.  Paris,  1828,  t.i.  p.  297. 

**  Die  Krankheiten  des  Fcetus,  p.  141. 


first  sight  appear,  too  many  instances  of  the 
fact  have  been  observed  by  authors  of  credit  to 
allow  of  any  doubt  remaining  on  the  subject ; 
I  must,  however,  add  that  no  case  of  the  kind 
has  come  under  my  own  observation.  So  far 
back  as  the  writings  of  Hippocrates,  we  have 
an  account  of  a  tapeworm  found  in  a  foetus  ; 
and  it  seems  very  probable  that  in  the  instance 
mentioned  by  Hufejand,*  in  which  he  found  a 
tapeworm  thirty  ells  long  in  a  child  of  six  months 
old,  the  animal  must  have  existed  in  the  child 
before  birth.  Kerkringiusf  found  in  a  foetus  of 
six  months  and  a  half,  whose  abdomen  was 
much  enlarged,  worms  of  the  kind  usually  met 
with  in  children  (ascaris  lumbricoidesor  vermi- 
cularis).  DolffiusJ  speaks  of  a  dead-born 
child  in  whose  intestines  he  found  a  knot  of 
worms ;  and  similar  observations  have  been 
made  by  Schroeter  and  others.  According  to 
Roederer  and  Wagner  the  whipworm  (trichuris) 
was  found  in  a  case  in  which  the  fcetus  partici- 
pated in  the  disease  (morbus  mucosus),  under 
which  the  mother  was  labouring  at  the  time. 
Other  instances  are  noticed  by  Brendel,§ 
Bloch,||  Rudolphi,H  and  Graetzer.** 

Imperforate  anus. —  Cases  of  imperforate 
anus,  of  the  ordinary  kind,  are  too  numerous 
and  too  well  known  to  require  any  particular 
observation ;  but  this  imperfection  has  been 
occasionally  accompanied  by  other  peculiarities 
deserving  to  be  noticed ;  one  or  two  are, 
therefore,  subjoined  in  addition  to  the  full 
account  of  congenital  malformations  of  this 
part  given  in  the  article  Anus. 

Dr  Steel  has  recently  recorded  the  particu- 
lars of  a  case  of  a  new-born  infant,  who  was 
observed,  one  or  two  days  after  birth,  to  have 
feculent  matter,  mingled  with  the  urine,  dis- 
charged by  the  urethra.  The  parts  behind  the 
scrotum  were  perfectly  natural  in  every  respect, 
except  the  want  of  an  anus,  of  which  there 
was  not  the  slightest  vestige ;  the  spot  where  it 
should  have  been  was  smooth,  and  of  a  uni- 
form colour  with  the  adjacent  parts;  the 
sphincter  muscle  was  evidently  wanting,  and 
there  was  nothing  to  indicate  an  accumulation 
of  faeces  in  the  vicinity. 

For  the  first  three  or  four  weeks  the  child 
continued  fretful,  and  was  evidently  declining 
in  vigour  and  growth  ;  but  from  that  period  to 
a  short  time  before  its  decease  it  apparently 
suffered  but  little,  nor  did  its  growth  or 
strength  seem  to  be  at  all  impeded.  It  was 
born  on  the  13th  of  April,  and  in  the  latter 
part  of  the  ensuing  March  its  bowels  became 
obstinately  obstructed,  the  scrotum  enlarged, 
and  became  extremely  tender;  and  on  the  30th 
of  the  same  month  it  died. 

On  dissection,  two  apple-seeds  of  a  large 

•  Journal  Bd.  18,  st.  i.  p.  3,  quoted  by  Brem- 
ser;  Traite  des  Vers  intestinaux,  p.  181. 

t  Specilegium  Anatomicum,  Amstel.  1670,  obs. 
79,  p.  154. 

%  Encyclop.  Med.  lib.  vi.  cap.  10,  p.  1011. 

\  Pallas,  dissert,  de  inf.  viv.  p.  59. 

II  Preisschrift  iiber  die  Erzeugung  Eingeweide- 
wurmer,  Berlin,  1782,  p.  38. 

f  Entozoa  i.  p.  387  ;  Pallas,  p.  43. 

**  Die  Krankheiten  des  fcetus,  Breslau,  1837, 
p.  107. 


FCETUS. 


337 


size,  together  with  a  portion  of  the  capsule  or 
hull  which  surrounds  them,  were  found  lodged 
in  the  urethra,  about  three-fourths  of  an  inch 
from  its  termination  ;  they  were  so  situated  as 
completely  to  obstruct  the  passage,  and  a 
small  opening  had  been  formed  immediately 
behind  them  in  the  urethra,  through  which 
some  of  the  contents  of  the  bladder  had  been 
infused  into  the  cellular  tissue,  and  extended 
to  the  scrotum,  producing  inflammation  and 
gangrene,  and  so  causing  the  child's  death. 

The  contents'  of  the  abdomen  appeared 
perfectly  natural,  except  the  colon  sinistra m 
or  descending  colon,  which  was  found  to  be 
entirely  destitute  of  the  sigmoid  flexure ;  the 
gut  passed  along  the  left  lumbar  and  through 
the  iliac  regions  in  nearly  a  straight  line  to  the 
neck  of  the  bladder,  into  which,  after  making 
an  abrupt  but  imperfect  curve,  and  being  sud- 
denly contracted  in  its  dimensions,  it  was  in- 
serted just  behind  the  base  of  the  prostate 
gland.  The  aperture  which  united  the  gut  and 
bladder  into  one  common  receptacle  for  their 
respective  contents  was  of  sufficient  capacity 
to  admit  a  large-sized  goose-quill ;  through 
this  aperture  the  urine  found  a  ready  egress 
into  the  intestine,  where,  becoming  united  with 
the  contents  of  that  receptacle,  it  was  forced 
back  into  the  bladder,  and  finally  excluded 
through  the  urethra.  The  space  between  the 
perineum  and  the  termination  of  the  intestine 
was  occupied  by  a  soft  fatty  substance,  but  there 
was  not  the  slightest  vestige  of  a  gut.* 

The  subjoined  woodcut  represents  the  parts 
of  one  half  the  natural  size  when  merely  in- 
flated. 


Fig.  160. 


a,  the  penis,    b,  the  bladder,    c,  the  colon. 


We  have  given  the  above  in  detail,  not 
merely  on  account  of  the  remarkable  nature  of 
the  anatomical  deviation,  but  as  connected 
with  the  still  more  interesting  fact,  that  life 
was  under  such  circumstances  sustained,  and 
healthy  defecation  accomplished  for  nearly  a 
year  after  birth. 

M.  Roux  of  Brignolles  operated  success- 
fully in  May,  1833,  on  a  new-born  child,  in 
whom  the  same  malformation  appears  to  have 
existed  ;  no  trace  of  anus  could  be  discovered 

*  American  Journal  of  the  Medical  Sciences, 
No.  xxx.  p.  404. 
vol.  n. 


in  the  perineum,  and  the  rectum  terminated  at 
the  urethra,  through  which  some  faecal  matter 
was  discharged  ;  the  infant  lived,  and  enjoyed 
good  health.* 

Rickets. — Deformities  of  the  bones  arising 
from  rickets  have  been  occasionally  observed 
both  in  the  child  at  birth  and  in  the  immature 
foetus  ;  but  the  instances  have  been  few  in 
number  ;  the  writer  has  never  had  an  opportu- 
nity of  examining  a  case  of  the  kind,  but  they 
have  been  described  by  authors  of  credit. 
Pinel  has  given  an  account  of  a  ricketty  foetus 
of  eight  months,  in  which  the  deformity  was 
chiefly  confined  to  the  lower  extremities.f 
ChaussierJ  examined  another  at  the  Maternite 
at  Paris,  in  which  there  was  distortion  of  the 
back  and  thorax,  with  softness  and  flexibility 
of  the  bones.  Several  other  writers  of  respect- 
ability have  described  this  affection.§ 

Jaundice. — The  fcetus  in  utero,  as  well  as 
the  child  at.  birth,  has  been  found  exhibiting 
all  the  characters  of  true  jaundice.  In  the  case 
of  a  lady,  related  by  Duges,||  who  was  herself 
liable  to  frequent  attacks  of  this  disease,  and 
had  biliary  calculi,  all  her  children  were  born 
dead,  and  strongly  coloured  by  jaundice.  It 
is  not,  however,  always  fatal  to  the  child  affected 
with  it  before  birth. 

Cirronosis. — Under  this  name^T  Professor 
Lobstein  of  Strasburg  has  described**  an  affec- 
tion of  the  foetus  in  which  the  serous  or  trans- 
parent membranes,  as  the  peritoneum,  pleura, 
pericardium,  and  arachnoid,  were  stained  of  a 
strong  yellow  colour,  which  in  some  instances 
was  found  to  pervade  also  the  brain,  spinal 
marrow,  and  the  great  sympathetic  nerves. 
The  cause  of  this  peculiar  colour  is  altogether 
a  matter  of  doubt,  but  it  differs  from  jaundice 
in  not  affecting  the  parenchymatous  cellular 
tissue  of  internal  organs,  the  subcutaneous 
cellular  tissue,  nor  the  skin,  and  it  is  found  so 
early  as  the  third  and  fourth  months,  a  period 
at  which  the  bile  is  not  as  yet  secreted.  For  a 
more  ample  account  of  this  affection  see  the 
article  Cirronosis. 

Accidental  morbid  tissues  observed  in  the 
fa'tus. — Some  of  these  have  been  already  inci- 
dentally noticed  under  different  heads  in  the 
present  article,   but  it  appears  desirable  to 

*  See  Medical  Gazette  for  June  28th,  1834  ;  or 
the  American  Medical  Journal,  No.  xxx.  p.  531, 
where  there  is  an  account  of  the  mode  in  which  the 
operation  was  performed. 

t  -La  Medeeine  eclairee  par  les  Sciences  Phy- 
siques, torn.  i.  p.  111. 

|  Diet,  des  Sci.  Med.  torn.  xvi.  p.  67. 

§  Loder,  Index  Prcparator.  &c.  Mosquse,  1823, 
sec.  ii.  D;  Sartorius,  Rachit.  Congenit.  Obs.  4to. 
Lipsiae,  1826,  cum  tabulis  ;  Romberg,  De  Rachit. 
Congenit.  Berolinae,  1817,  cum  tabulis;  Otto, 
Seltene  Ueobachtung,  1  Sam.  tab.  i.  fig.  1.  ;  Soem- 
mering, Abbildung.  u.  lieschreib.  einiger  Missge- 
burten,  p.  30.  pi.  xi ;  Uordenave,  Mem.  de  Mathem. 
et  Phys.  torn.  iv.  p.  545  ;  Lepelletier,  Maladie 
Scrofuleuse,  Paris,  1830;  Henckel,  Abhandl.  Chi- 
rurg.  Oper.  Th.  ii.  p.  14  :  Glisson  de  Rachitide, 
p.  178. 

||  Diet,  de  Med.  et  de  Chir.  Prat.  t.  viii.  p.  301. 
^  From  xippoc,  yellow,  and  vocroc,  a  disease. 
**  In  the  Repertoire  Generale  d'Anatomie,  &Ci 
No.  i.  p.  141,  and  plate  i v. 

7, 


338 


BONES  OF  THE  FOOT. 


advert  to  them  here  as  a  group  for  the  sake  of 
distinction. 

Tubercles  have  been  found  by  the  writer  and 
others,  as  already  referred  to,  in  the  lungs, 
liver,  brain,  spleen,  peritoneum,  and  mesen- 
tery, the  glands  of  which  have  been  found  by 
Oihler  in  a  state  of  complete  scrofulous  dege- 
neration, not  only  in  children  born  of  a  scro- 
fulous mother,  but  in  others  also :  in  some 
instances  the  tubercular  formations  were  found 
in  a  state  of  suppuration.* 

Scirrhous  tumours  have  been  already  des- 
cribed as  found  in  the  heart. 

The  only  instance  of  fungus  heematodes  in  : 
the  fetus  of  which  the  writer  is  aware,  is  one. 
which  he  had,  not  long  since,  an  opportunity 
of  observing  f  with  Dr.  Alcock  and  Dr.  Ev.an- 
son  in  a  child  which  lived  only  nine  weeks  ;.  at 
birth  an  unusual  fulness  was  observed  about 
the  perineum  and  anus,  which  .  increased  ra- 
pidly until  these  parts  became  greatly  pro- 
truded, and  a  tumour  was  formed  of  the  -si?e 
of  a  very  large  orange ;  convulsions  came  on, 
and  the  child  died  after  much  suffering  :  oh 
examination,  the  tumour  was  found  to  be  a 
perfect  specimen  of  fungus  haematodes. 

Bibliography. — Licetus  ( Fortun. )  De  perfecta 
constitutione  hominis  in  utero,  &c.  4to.  Patavii, 
1616'.  Alsaro  della  Crore,  (Vincent),  Disquisitio 
generalis  ad  historiam  foetus  emortui  nonimestvis, 
&c.4to.  Romae,  1627.  Riolamisf  Joan.  )F(£tnshisto- 
ria,  8vo.  Parisiis,  1628.  Fridericus  ( Joan.  Arnoud.J 
TofivaTfA.cc  ia.Tp.Kov  foetum  quoad  principia,  partes 
communes  et  proprias,  differentias,  morbos  et  sym- 
ptomata,  eorumdemque  curationem  offerens  atque 
exponens,  4to.  Ienae,  1658.  Frank  de  Frankenau, 
(  Gcorg.)  De  impuberibus  generantibus  et  parien- 
tibus,  foetu  in  foetu,  embryo  in  embryo,  et  foetu  ex 
mortua  matre,  &c.  Duettel,  ( Phil.  Jac.)  De 
rnorbis  fcetus  in  utero  materno,  4to.  Halae  Magdeb. 
1702.  Valentini,  De  morbis  embryonum,  Giessae, 
1704.  Starch,  Kinderkrankheiten,  Eisenach,  1750. 
Socin  ( Joan.  Abel.)  De  foetu  hydropico,  4to.  Basilae, 
1751.  Jceger,  Observations  de  foetibus  recens 
natis  jam  in  utero  mortuis,&c.  4to.  Tubings,  1767. 
Raulin,  Traite  des  Maladies  des  Enfans,  Paris, 
1768.  Gruner,  De  Naevorum  Originibus,  Jenae, 
1778.  Zierhold,  De  notabilibus  quibusdam  quEE 
foetui  in  utero  contingere  possunt,  Halae,  1778. 
Hoogeveen,  Traetatus  de  fcetus  humani  morbis,  8vo. 
Lugduni  Bat.  1784.  Engelkart,  Dissertatio  inaug. 
Med.  sistens  morbos  hominum  a  prima  conforma- 
tione  usque  ad  partum,  4to.  Jenae,  1792.  Chaus- 
sier,  Discours  prononce  a  l'hospice  de  la  Maternite, 
Juin  1810  et  Juin  1812.  Ej,  Proces  Verbal  de  la 
distribution  des  prix,  1812.  Ej.  Bulletins  de  la 
Faculte  de  Medecine.  Paris,  1813  et  1821.  Murat, 
Diet,  des  Sciences  Med.  art.  Fcetus,  Paris,  1812. 
Feller,  P'adiatrik,  Subzbach,  1814.  Oehler,  Pro- 
legomena in  emhryonis  humani  pathologiam,  Diss, 
inaug.  Lipsiae,  1815.  Joerg,  Zur  Physiologie  und 
Pathologie  des  Embryo,  Lipsiae,  1818.  F.  B, 
Osiander,  Handbuch  der  Entbindungskunst,  Tubin- 
gae,  1819.  Seeligmann,  Dissertatio  de  morbis 
fcetus  humani,  Erlangae,  1820.  Zuccarini,  Zur 
Beleuchtung  der  Krankheiten  der  menschlichen 
Frucht,  Erlangen,  1824.  Desormeaux,  Diet,  de 
Med.  torn.  xv.  art.  (Euf ;  Paris,  1826.  Prosper,  S. 
Denis,  Recherches  d'Anat.  et  de  Physiol,  patholo- 
gique  sur  plusieurs  maladies  des  Enfans  nouveaux 
lies.  Paris,  1826.    Hufeland,  Die  Krankheiten  der 

*  See  section  on  the  state  of  the  Lungs,  and 
Billard,  p.  648. 

t  See  his  Exposition  of  the  Signs  and  Symptoms 
of  Pregnancy,  &c.  p.  152. 


Ungebomen  und  die  Vorsqrge,  &c.  Journal  der 
praktischen  Heilkunde,  .1827.'  Meissner,  Kinder- 
krankheiten,  Leipzig,.  1828.  Hardegg,  De  Morbis 
fcetus  humani,  Tubingae,  1828."..  Billard,  Traite 
des  Maladies  des  Enfans  nouvdasx-nes  et  a  la 
mammelle,  Paris,.  1828.  Bergli,  De«Morbis  fcetus 
humani,  Lipsiae,  1829.  Cruveilhier,  Anatomie 
Pathologique  du  corps  humain,  Paris,  1829. 
Andry,  Memoire  sur  les  Maladies  du  fetus,  &c. 
Journal  des  Progr^s,  1830.  •  Zurmeyer', De  Mor- 
bis fcetus,  Bonnae,  1832.  Griietzer,  Die  Krankhei- 
ten des  fcetus,  Breslau,  1837.  » 

;  (W'.'F.  Montgomery.) 

FOOT,  BONES  OF  THE  (in  human  ana- 
tomy).— The  foot  (pes  ;  Gr.  Troy;;  Fr.  It  pied  ; 
Germ,  der'  Fuss )  forms  the  inferior  segment  of 
the  lowerextremity,' being  united  to  the  leg  at 
the  ankle-joint  nearly  at  a  right  angle,  so  that 
in  the  erect  position  on  a  plane  surface  the  foot 
is  horizontal.  The  outline  of  the  foot  circum- 
scribes an  ovpidal  figure,  the  long  axis  of  which 
is  directed  from  before  backwards;  and  in  the 
same  direction  the  foot  is  divided  into  three 
segments,  the  anterior  one  surpassing  that 
behind  it  in  mobility,  but  falling  short  of  it  in 
solidity.  These  divisions  are  the  tarsus,  meta- 
tarsus, and  the  toes.  - 

The  size  of  the  foot,  taken  as  a  whole,  varies 
in  different  individuals  :  it  always  exceeds  that 
of  the  hand,  chiefly,  however,  in  length  and 
thickness,  its  breadth  being  less  than  that  of 
the  hand.  In  the' hand  we  find  divisions  pre- 
cisely analogous  to  those  of  the  foot  above 
mentioned  and  similarly  constructed,  with  this 
difference,  that  the  solid  part  of  the  foot  is 
more  solid  and  more  developed  in  every  way 
than  the  corresponding  part  of  the  hand,  but 
the  moveable  parts  possess  less  mobility  than 
the  analogous  segments  of  the  hand.  The 
parls  of  the  foot  and  hand,  as  Mr.  Lawrence 
observes,  are  disposed  inversely  in  respect  to 
their  importance.  The  posterior  portion  of  the 
former  and  the  anterior  of  the  latter  are  of  the 
most  consequence  and  possess  the  most  remark- 
able characters.  In  short,  the  foot  is  nothing- 
more  than  the  hand  so  modified  as  to  afford  a 
firm  basis  of  support  to  the  inferior  extremity 
in  the  erect  posture.  One  of  the  most  remark- 
able of  these  modifications  is  that  manifest  in 
the  metatarsal  bone  of  the  great  toe,  which 
corresponds  to  the  metacarpal  bone  of  the 
thumb.  The  latter  bone  is  connected  with  the 
carpus  so  that  it  forms  an  acute  angle  with  the 
second  metacarpal  bone.  It  enjoys  at  its  arti- 
culation with  the  carpus  a  considerable  degree 
of  mobility,  in  virtue  of  which  exists  the 
opposable  faculty  of  the  thumb.  On  the  other 
hand,  the  metatarsal  bone  of  the  great  toe 
enjoys  but  a  very  limited  degree  of  mobility  at 
its  articulation  with  the  tarsus  :  it  lies  parallel 
to  the  adjacent  bone  and  possesses  considerable 
strength.  These  remarkable  differences,  says 
Mr.  Lawrence,  are  easily  understood  when  we 
consider  that  the  great  toe,  as  one  of  the  points 
on  which  the  body  is  supported,  requires 
solidity;  while  the  thumb,  being  concerned  in 
all  the  numerous  and  varied  motions  of  the 
hand,  must  be  organised  for  mobility.  Those 
animals  in  which  the  inferior  segments  of  both 
anterior  and  posterior  extremities  are  eminently 


BONES  OF  THE  FOOT. 


339 


required  for  prehension  have  the  inferior  seg- 
ments of  all  four  extremities  organised  as  hands, 
and  are  thence  denominated  Quadrnmanous. 

The  most.elevated  part  of  the  foot  is  at  its 
posterior  part,  where  it  contributes  to  form  the 
ankle-joint;  thence  it  inclines  forwards,  gra- 
dually expanding  .transversely,  and  presenting 
a  more  or  less  convex'  surface  from  behind 
forwards.    This  is  the  dorsum  pedis,  the  instep. 

The  inferfo.r  surface  likewise  expands  as  it 
proceeds  forward's.  It  js  slightly  concave  in 
the  transverse  direction,  and  more-  manifestly 
so  in  the  antero-posterior  one  ;  this  latter,  how- 
ever, varies  in  a  degree  proportionate  to  the 
convexity  of  the  dorsum'.  -  This  is  the  planta 
pedis,  the  sole. 

The  internal  edge  of  the  foot  corresponds  to 
the  great  toe,  the  external  edge  to  the  little  toe, 
the  anterior  to  the  ends  of -the  toes, 'and  the 
posterior  extremity  of  the  foot  is  formed  by  the 
os  calcis. 

I.  Tarsus  (Germ,  die  Fusswurzel). — Nearly 
the  posterior  half  of  the  foot  is  occupied  by 
the  tarsus,  which  is  arranged  in  the  form  of  an 
arch,  convex  superiorly,  on  the  highest  point 
of  which  rests  the  weight  of  the  leg.  Seven 
bones  enter  into  the'  formation  of  the  tarsus ; 
they  are  arranged  in  two  sets  or  rows.  The 
posterior  row  is  formed  by  the  astragalus  and 
os  calcis,  the  anterior  row  by  the  os  naviculare, 
the  os  cuboideum,  and  the  three  cuneiform 
bones.  Through  the  medium  of  the  first  two 
bones  of  the  anterior  row  that  row  is  articulated 
with  the  posterior. 

1 .  Astragalus  {ocar^aya/Koq,  tet^w^o?,  os  ba- 
listic,  talus;  Fr.  Vastrugale  ;  Germ,  das  Knoch- 
elbein  oder  Sprungbcin ). — This  bone  is  situated 
between  the  tibia  and  the  os  calcis,  and  has 
the  navicular  bone  in  front  of  it.  In  point  of 
size  it  ranks  second  among  the  tarsal  bones, 
the  os  calcis  being  first. 

The  astragalus  is  commonly  divided  into 
three  parts  for  the  purposes  of  description,  viz. 
the  head,  neck,  and  body.  The  head  is  that 
convex  portion  which  forms  the  anterior  part  of 
the  bone,  and  which  is  entirely  articular.  This 
smooth,  oval,  articular  head  is  adapted  to  the 
posterior  concavity  of  the  navicular  bone.  The 
aspect  of  this  surface  is  forwards,  inwards,  and 
slightly  downwards.  On  the  inferior  part  of 
the  head  we  notice  another  articular  facet, 
planiform,  situated  internally,  and  generally  con- 
tinuous with  the  articular  surface  last  described. 
By  means  of  this  facet  the  astragalus  moves 
on  a  corresponding  surface  on  the  upper  and 
anterior  part  of  the  os  calcis. 

The  head  of  the  astragalus  is  connected  to 
the  body  by  a  narrow  contracted  portion  called 
the  neck,  which  is  rough  on  all  its  surfaces, 
giving  insertion  to  ligaments  and  perforated  by 
numerous  foramina  for  the  transmission  of 
vessels.  The  external  side  of  the  neck  pre- 
sents a  remarkable  excavation,  which  affords 
insertion  to  and  contributes  to  bound  a  space 
for  the  lodgement  of  a  strong  ligament  which 
passes  between  the  astragalus  and  os  calcis. 

All  that  portion  which  is  behind  the  neck 
constitutes  what  is  called  the  body,  on  which 
we  notice  five  surfaces,    a.  The  superior  sur- 


face forms  an  articular  trochlea,  convex  from 
before  backwards,  and  slightly  concave  trans- 
versely; it  articulates  with. the  inferior  extremity 
of  the, tibia:*  immediately  in  front  of  it  there 
is  a  roughness  of  very  limited  extent,  which 
affords  insertion  to  ligamentous  fibres,  b.  The 
posterior  surface  is  almost  wholly  occupied  by 
a  well-marked  groove,  which  passes  obliquely 
downwards  and  in  wards,  and  is  destined  to  lodge 
the  tendon  of  the  flexor  pollicis  longus.  c.  The 
external  surface  is  occupied  by  a  triangular 
facet,  whose  base  is  direct  upwards  and  is  con- 
tinuous with  the  articular  part  of  the  superior 
surface  of  the  body  ;  this  facet  articulates  with 
the  fibula.  It  is  bounded  below  and  behind 
by  a  rough  portion  for  ligamentous  insertion. 
d.  "The  internal  surface  is  also  articular  in  its 
upper  half  for  the  adaptation  of  the  inner 
malleolus :  it,  too,  is  triangular,  and  by  its 
"base  is  continuous  with  the  superior  surface. 
Below  this  internal  malleolar  facet  the  bone  is 
rough  and  irregular,  and  here-  the  internal 
lateral  ligament  of  the  ankle-joint  is  inserted. 
Lastly,  the  inferior  surface  is  occupied  almost 
entirely  by  a  concave  articular  facet,  oval,  with 
its  long  axis  directed  from  within  outwards  and 
forwards;  this  facet  is  articulated  with  a  corre- 
sponding one  upon  the  os  calcis.  Immediately 
in  front  of  it  there  is  a  deep  and  narrow  depres- 
sion which  separates  it  from  an  oval  planiform 
facet  for  articulation  with  tire  sustentaculum  of 
the  os  calcis.    '  /i^J-  '■ — 

2.  Os  calcis  (ir-re^a,  a-y.iXn;;  Fr.  le  calca- 
ncum,  os  du  talon ;,  Germ,  das  Fcrsenbein  ;  the 
heel-bone). — This  is  the  k^ges-t  bone  of  the 
tarsus ;  it  occupies  the  most  posterior  part  of 
the  foot,  and  is  situated  immediately  under- 
neath the  astragalus,  of  which  it  constitutes  the 
principal  support.  Its  greatest  extent  is  from 
before  backwards.  It  is  somewhat  flattened  on 
the  sides :  its  direction  is  horizontal,  the  foot 
in  standing  resting  upon  the  most  posterior  part 
of  its  inferior  surface.  This  horizontal  direc- 
tion of  the  heel-bone  is  one  of  the  arguments 
which  anatomy  affords  in  support  of  the  asser- 
tion that  the  erect  posture  is  natural  to  man. 

We  notice  six  surfaces  upon  this  bone. 

a.  The  superior  surface,  or  that  upon  which 
the  astralagus  rests.  On  it  we  observe  in  front 
three  articular  facets,  separated  from  each  other 
by  distinct  intervals:  the  first  or  smallest  is 
situated  at  the  anterior  edge  of  the  surface  and 
at  its  internal  angle,  and  is  articulated  with  the 
facet  on  the  inferior  part  of  the  head  of  the 
astragalus ;  it  is  not  constant.  The  second  is 
posterior  and  internal  to  the  last,  separated 
from  it  by  a  rough  depression  about  a  quarter 
of  an  inch  in  extent.  This  is  oval,  slightly  con- 
cave, and  is  marked  upon  a  projecting  portion 
of  the  bone  which  overhangs  the  anterior  part 
of  the  internal  surface,  and  which  is  known 
under  the  name  of  processus  interims,  or  sus- 
tentaculum cervicis  tali  of  Albinus;  it  supports 
and  is  articulated  with  a  corresponding  facet 
on  the  under  surface  of  the  neck  of  the  astra- 
galus.   A  narrow  groove  on  the  outside  of  the 

*  See  further  description  in  the  article  Ankle- 
Joint. 

z  2 


340 


BONES  OF  THE  FOOT. 


facet  last  named  separates  it  from  the  third  and 
largest  one ;  this  is  articulated  with  the  facet 
which  is  on  the  inferior  surface  of  the  body  of 
the  astragalus ;  it  is  oval,  convex,  and  its  long 
axis  directed  forwards  and  outwards.  Imme- 
diately in  front  of  this  articular  facet  there  is  a 
hollow,  rough,  non-articular  surface  for  the 
insertion  of  the  ligament  which  connects  the 
astragalus  to  the  os  caleis,  and  behind  the  facet 
the  remaining  portion  of  the  superior  surface 
of  the  bone  is  also  non-articular,  slightly  exca- 
vated from  before  backwards,  varying  in  length 
in  different  subjects,  and  on  this  variety  de- 
pends the  diversity  in  the  length  of  the  heel. 
b.  The  posterior  surface,  oval  in  its  outline, 
rough  and  fibrous  in  its  inferior  half,  where  the 
tendo  Achillis  is  inserted,  smooth  in  its  supe- 
rior half  where  a  bursa  is  placed,  over  which 
the  tendon  glides,  c.  The  inferior  or  plantar 
surface,  nearly  equal  in  extent  to  the  superior, 
and  in  the  natural  position  directed  obliquely 
upward  and  forwards.  Here  we  find,  in  ex- 
amining the  parts  from  behind  forwards,  first, 
two  tubercles,  upon  which  the  heel  rests  in 
standing,  and  which  seem  peculiarly  to  cha- 
racterize the  human  heel-bone.  These  tuber- 
cles are  separated  from  each  other  by  a  depres- 
sion; the  internal  one  is  greatly  the  larger — it 
affords  attachment  to  the  short  flexor  of  the  toes  ; 
the  external  one  is  small  and  pointed,  and  to  it 
are  attached  the  abductor  minimi  digiti  muscle 
and  the  plantar  fascia.  Secondly,  in  front  of 
these  tubercles  the  bone  is  very  rough  and  flat  to 
within  half  an  inch  of  its  anterior  margin, 
where  it  is  slightly  grooved  transversely.  The 
whole  of  this  portion  gives  insertion  to  the 
strong  calcaneo-cuboid  ligament,  d.  The  ante- 
rior or  cuboid  surface,  which  is  entirely  articu- 
lar, triangular,  with  its  base  upwards,  slightly 
concave,  and  articulated  with  the  cuboid  bone. 
e.  The  external  surface,  quite  subcutaneous, 
so  that  here  the  bone  is  greatly  exposed  to 
injury,  and  may  be  easily  got  at  for  surgical 
operation.  It  is  slightly  convex,  its  posterior 
half  being  double  the  size  of  the  anterior  in  ver- 
tical measurement;  at  the  anterior  part  of  the 
former  there  are  two  superficial  grooves  directed 
obliquely  forwards  and  downwards,  separated 
by  a  slightly  prominent  tubercle.  The  anterior 
of  these  grooves  gives  passage  to  the  tendon  of 
the  peroneus  brevis,  the  posterior  to  that  of 
the  peroneus  longus.  f  The  internal  surface, 
excavated  in  its  whole  extent,  lodges  the  ten- 
dons and  nerves  which  are  passing  from  the 
back  of  the  leg  to  the  sole  of  the  foot ;  at  the 
junction  of  its  anterior  and  posterior  halves  it 
is  overlapped  by  the  sustentaculum,  the  inferior 
surface  of  which  is  grooved  by  the  tendon  of 
the  long  flexor  of  the  great  toe. 

3.  Os  cuboideum,  ( os  cubijbrme,  Fr.  le  cu- 
boide,  Germ,  das  Wurfelbein.) — This  bone 
forms  the  external  one  of  the  second  row  of 
tarsal  bones ;  it  is  situated  between  the  os 
calcis  behind  and  the  fourth  and  fifth  meta- 
tarsal bones  in  front ;  in  point  of  size  it  ranks 
next  to  the  astragalus.  Six  surfaces  may  be 
described  upon  it.  a.  The  superior  or  dorsal 
surface,  forming  an  inclined  plane,  directed 
downwards  and  outwards ;  it  is  rough  for  liga- 


mentous insertion,  b.  The  external  surface, 
more  properly  an  edge,  very  limited  in  extent, 
chiefly  occupied  by  the  commencement  of  the 
groove  for  the  peroneus  longus  muscle,  c.  The 
inferior  or  plantar  surface,  which  in  front  pre- 
sents a  deep  groove  directed  obliquely  forwards 
and  inwards,  parallel  to  the  anterior  edge,  and 
destined  to  lodge  the  tendon  of  the  peroneus 
longus.  The  posterior  edge  of  this  groove  is 
very  prominent,  and  with  the  remainder  of  this 
surface,  which  is  rough,  affords  insertion  to 
the  calcaneo-cuboid  ligament,  d.  The  internal 
surface  has  at  its  upper  and  posterior  part  a 
triangular  plane  articular  facet  for  articulation 
with  the  external  cuneiform  bone,  and  some- 
times a  smaller  one  for  articulation  with  the 
navicular;  the  rest  of  this  surface  is  irregular 
and  rough  for  ligamentous  insertion,  e.  The 
anterior  or  metatarsal  surface  is  wholly  arti- 
cular, and  is  divided  by  a  vertical  line  into  two 
facets,  an  outer  one  triangular  and  plane  for 
the  fifth,  and  an  inner  one  quadrilateral  and 
very  slightly  concave  for  the  fourth  metatarsal 
bone.  The  external  of  these  facets  is  inclined 
obliquely  outwards  and  backwards.  ,/.  The 
posterior  surface  is  oval,  with  its  long  axis 
directed  downwards  and  outwards;  itis  wholly 
articular  and  adapted  to  the  anterior  surface  of 
the  os  calcis. 

4.  Os  scaphoideum  (from  ax.a.<pi),  navis,  os 
naviculare,  Fr./e  scaphoide,  Germ. das  Kahnbein, 
oder  Sc/iijforrnige  Knochen,)  forms  the  posterior 
and  internal  bone  of  the  second  tarsal  row,  and 
is  placed  between  the  three  cuneiform  bones  in 
front  and  the  astragalus  behind.  It  is  oval  in 
shape,  with  its  long  axis  directed  obliquely 
downwards  and  inwards;  the  small  end  of  the 
oval  is  situated  internally  and  inferiorly,  and 
presents  a  distinct  prominence  or  process  (tuber 
ossis  navicularis ),  which  gives  insertion  to  some 
fibres  of  the  tendon  of  the  tibialis  posticus. 

Four  surfaces  may  be  described  upon  this 
bone.  a.  The  superior  or  dorsal  surface,  of 
great  extent,  convex,  very  rough  for  the  inser- 
tion of  ligaments,  and  perforated  by  foramina. 
b.  The  inferior  surface,  irregularly  concave, 
and  very  rough,  also  affording  insertion  to 
ligaments,  c.  The  posterior  surface,  entirely 
articular,  oval  and  concave,  adapted  to  the 
head  of  the  astragalus,  although  considerably 
less  in  extent  than  it.  This  constitutes  what  is 
called  the  glenoid  cavity,  d.  The  anterior  sur- 
face, also  articular  and  convex,  divided  by  two 
lines  which  converge  from  above  downwards, 
into  three  triangular  surfaces  for  articulation 
with  the  three  cuneiform  bones. 

5.  Ossa  cuneiformia  (Fr.  les  os  cuneiformes, 
Germ,  die  Keilfbrmigen  Knochen.)  These 
bones  are  interposed  between  the  navicular 
bone  behind  and  the  three  internal  metatarsal 
bones  in  front ;  they  are  arranged  in  the  form 
of  an  arch,  of  which  the  middle  cuneiform  is 
the  central  or  key-bone.  Each  is  very  distinctly 
wedge-shaped;  the  two  outer  ones  have  the 
acute  edge  directed  downwards,  but  the  inter- 
nal one  has  it  directed  upwards. 

The  internal  cuneiform  bone  is  at  once  dis- 
tinguishable from  the  others  by  its  great  size. 
By  means  of  an  oval  concave  articular  surface, 


BONES  OF  THE  FOOT. 


341 


whose  long  axis  is  vertical,  it  is  articulated 
with  the  anterior  and  internal  part  of  the  navi- 
cular bone,  and  in  front  a  large  and  irregular, 
slightly  concave  articular  facet  adapts  it  to  the 
posterior  extremity  of  the  metatarsal  bone  of 
the  great  toe.  Its  inner  surface  is  convex  and 
rough  for  ligamentous  insertion  ;  on  it,  towards 
its  anterior  part,  we  observe  an  impression, 
sometimes  an  eminence,  for  the  insertion  of 
the  tibialis  anticus  tendon ;  and  its  plantar 
surface,  the  base  of  the  wedge,  is  thick  and 
prominent,  and  affords  insertion  to  ligamentous 
fibres  as  well  as  to  those  of  the  tibialis  posticus 
tendon.  The  external  surface  is  articulated  in 
front  with  the  second  metatarsal  bone,  and 
behind  with  the  middle  cuneiform,  by  means 
of  an  oblong  articular  facet,  which  extends 
along  the  upper  part  of  this  surface  from  before 
backwards  parallel  to  the  acute  edge.  The 
remainder  of  the  external  surface  is  rough  for 
ligamentous  insertion,  excepting  a  small  por- 
tion about  the  sixth  of  an  inch  broad,  which, 
extending  along  the  posterior  edge,  is  articular 
and  continuous  with  the  posterior  surface  of 
the  bone. 

The  middle  or  second  cuneiform  bone  is  the 
smallest  of  the  three ;  its  base  is  uppermost, 
rough  and  convex ;  its  posterior  surface  is  tri- 
angular with  the  base  superior ;  it  is  articular 
and  adapted  to  the  middle  facet  on  the  anterior 
surface  of  the  navicular;  its  anterior  surface  is 
also  triangular  and  articulated  with  the  second 
metatarsal  bone ;  its  inner  surface  is  articular 
along  its  upper  and  posterior  edges,  and  rough 
in  the  remainder  of  its  extent;  this  surface  is 
in  contact  with  the  inner  cuneiform.  The  outer 
surface  is  articular  along  half  of  its  upper  edge 
and  the  whole  of  its  posterior,  but  rough  in 
the  remainder,  and  by  means  of  the  articular 
portions  is  connected  with  the  external  cunei- 
form bone. 

The  external  or  third  cuneiform  bone  is 
second  in  point  of  size  ;  it  is  bounded  on  the 
outside  by  the  cuboid,  behind  by  the  navicular, 
on  the  inside  by  the  middle  cuneiform,  and  in 
front  by  the  third  metatarsal  bone.  Its  pos- 
terior and  anterior  surfaces  are  both  plane  and 
articular,  the  one  for  the  navicular,  the  other 
for  the  third  metatarsal  bone.  The  base  of  the 
wedge  is  situated  on  the  dorsal  surface  of  the 
foot,  and  is  rough.  The  internal  surface 
presents  at  its  posterior  edge  a  facet  for  arti- 
culation with  the  middle  cuneiform,  and  in 
front  another  for  the  second  metatarsal ;  the  re- 
mainder is  non-articular.  The  external  surface 
presents,  towards  its  upper  and  posterior  angle, 
a  plane  triangular  facet,  which  is  adapted  to  a 
similar  one  on  the  inner  surface  of  the  cuboid, 
but  in  the  rest  of  its  extent  it  is  rough  and  non- 
articular. 

Structure  of  the  tarsal  bones.— Like  all  the 
short  bones,  those  of  the  tarsus  are  composed 
of  a  mass  of  spongy  tissue  surrounded  by  a 
thin  and  papyraceous  layer  of  compact.  Hence 
these  bones  are  remarkable  for  their  extreme 
lightness. 

Developement.  —  In  the  third  month  the 
cartilaginous  framework  of  these  bones  is 
already  apparent.    The  largest  two  begin  to 


ossify  before  birth ;  the  os  calcis  commences  at 
from  the  fifth  to  the  seventh  month,  by  a  single 
point  of  ossification  situate  about  the  middle  of 
the  bone  rather  nearer  to  its  anterior  part,  and  the 
ossification  is  not  completed  till  eight  or  ten  years 
after  birth,  when  another  point  appears  in  the 
posterior  part  of  the  bone,  and  by  the  extension 
of  it  to  the  first  point,  which  is  finished  about 
the  fifteenth  year,  the  process  is  completed. 
The  ossification  of  the  astragalus  commences 
about  the  sixth  month.  The  cuboid  and  navi- 
cular begin  to  ossify  immediately  after  birth 
by  one  point  each,  and  the  three  cuneiform 
bones  are  ossified,  the  internal  about  the  end 
of  the  first  year,  the  middle  and  external  about 
the  fourth  year. 

II.  Metatarsus  ( der  Mittelfuss ). — This  seg- 
ment of  the  foot  is  composed  of  five  bones 
placed  parallel  to  each  other  in  front  of  the 
tarsus,  with  which  their  posterior  extremities 
are  articulated.  These  bones  are  distinguished 
numerically,  counting  from  within  outwards  ; 
a  distinct  interosseous  space  intervenes  between 
each  pair  of  bones,  which  in  the  recent  state  is 
filled  by  muscle.  From  the  arched  form  of 
the  tarsus,  the  metatarsus  naturally  takes  a 
similar  arrangement  by  reason  of  its  articula- 
tion with  it,  and  consequently  we  observe  that 
it  is  convex  on  its  dorsal  surface  and  concave 
on  its  plantar. 

The  metatarsal  bones  possess  certain  general 
characters  in  common;  they  belong  to  the  class 
of  long  bones,  and  consequently  each  has  its 
shaft  and  two  extremities.  The  shaft  in  all  is 
prismatic,  slightly  curved,  convex  on  the  dor- 
sal, concave  on  the  plantar  surface;  two  of  the 
surfaces  of  the  shaft  are  lateral,  and  correspond 
to  interosseous  spaces ;  the  third  is  superior, 
and  corresponds  to  the  dorsum  of  the  foot. 

The  posterior  or  tarsal  extremity  of  each 
metatarsal  bone  is  wedge-shaped,  the  base  of 
the  wedge  being  on  the  dorsal  aspect.  Three 
articular  facets  may  be  noticed  on  each,  ex- 
cepting the  first  and  fifth.  The  posterior  of 
these  is  triangular  and  plane,  articulated  with 
the  tarsal  bones ;  the  remaining  two  are  lateral, 
and  adapted  to  corresponding  ones  on  the 
metatarsal  bones  on  each  side. 

The  anterior  or  digital  extremity  of  each 
metatarsal  bone  presents  an  articular  head  or 
condyle,  flattened  upon  the  sides,  oblong  from 
above  downwards,  and  much  more  extended 
inferiorly  or  in  the  direction  of  flexion  than 
superiorly  or  in  that  of  extension.  This  is 
articulated  with  the  posterior  extremity  of  the 
metatarsal  phalanx.  On  each  side  of  the  con- 
dyle there  is  a  depression,  and  behind  that 
an  eminence  to  which  the  lateral  ligament  of 
the  metatarso-phalangeal  joint  is  attached. 

In  addition  to  the  characters  above  men- 
tioned, there  are  certain  special  characters 
belonging  to  particular  metatarsal  bones  which 
enable  us  to  distinguish  them  from  each 
other. 

The  first,  or  metatarsal  of  the  great  toe,  is 
distinguished,  1.  by  its  considerable  size  and 
its  being  the  shortest  of  the  five  bones;  2.  its 
tarsal  extremity  is  semilunar  and  concave,  and 
has  no  lateral  articular  facet;   3.  its  digital* 


342 


BONES  OF  THE  FOOT. 


extremity  has  on  its  plantar  portion  two  con- 
cavities separated  by  a  ridge,  with  which  the 
sesamoid  bones  articulate.  The  second  cha- 
racteristic is  one  which  peculiarly  distinguishes 
this  bone. 

The  second  is  the  longest ;  it  extends  farther 
backwards  than  any  of  the  others,  and  is 
lodged  in  a  mortise-shaped  cavity  formed  by 
the  three  cuneiform  bones. 

The  fifth  has  the  following  characters  : — 1. 
it  is  shorter  than  the  second,  third,  and  fourth  ; 
2.  it  has  no  lateral  articular  facet  on  the  outer 
side  of  its  tarsal  extremity  ;  3.  on  this  same  side 
it  is  prolonged  backwards  and  outwards  into 
a  long  pyramidal  process,  which  gives  insertion 
to  the  tendon  of  the  peroneus  brevis.  This 
process  being  quite  subcutaneous,  it  is  a  useful 
guide  to  surgeons  in  the  partial  amputation 
of  the  foot  at  the  tarso-metatarsal  articulation. 

The  third  and  fourth  resemble  each  other 
very  closely;  the  third,  however,  is  a  little 
longer  than  the  fourth,  and  the  posterior  ar- 
ticular facet  on  the  fourth  is  more  quadrangular 
than  triangular. 

The  structure  of  the  metatarsal  bones  is  that 
of  the  long  bones  in  general. 

Developement.- — -Each  metatarsal  bone  has 
two  points  of  ossification  ;  one  for  the  body, 
the  other  for  the  anterior  extremity,  except 
in  the  case  of  the  first,  in  which  the  second 
ossific  point  is  for  the  tarsal  extremity.  Be- 
tween the  third  and  fourth  months  the  osseous 
point  of  the  body  commences,  and  in  the 
full-developed  fcetus  the  body  is  completely 
ossified.  In  the  course  of  the  second  year 
the  point  for  the  extremity  appears ;  the  epi- 
physis of  the  first  metatarsal  bone  is  united 
first,  about  the  eighteenth  year,  and  this  union 
precedes  that  of  the  others  by  about  twelve 
months. 

Toes  ( Digit i  pedis;  Fr.  les  orteils ;  Germ. 
die  Zehen J.— The  toes  are  numbered  from  the 
inuer  or  great  toe;  they  gradually  diminish  in 
length  from  the  first  to  the  fifth  :  the  four 
outer  ones  consist  each  of  three  portions  or 
phalanges;  the  great  toe  has  only  two.  The 
phalanges  are  best  named  from  their  relations, 
viz.  metatarsal,  middle,  and  ungual. 

The  ?7ietatarsal  phalanges  are  considerably 
the  longest.  The  shaft  in  each  is  prismatic,  like 
that  of  the  metatarsal  bones,  convex  on  the  dor- 
sal, concave  on  the  plantar  surface.  On  the  pos- 
terior extremity  is  a  concave  facet,  articulated 
with  the  anterior  head  or  condyle  of  the  cor- 
responding metatarsal  bone.  The  anterior  ex- 
tremity is  less  swollen  than  the  posterior:  it 
is  marked  by  an  articular  surface,  which  ex- 
tends much  more  on  the  inferior  surface  than 
the  superior;  this  is  concave  transversely,  but 
convex  from  above  downwards,  and  is  arti- 
culated with  the  posterior  extremity  of  the 
middle  phalanx.  All  the  metatarsal  phalanges 
possess  these  general  characters :  that  of  the 
great  toe  is  very  considerably  thicker  than  the 
others,  and  is  slightly  longer;  the  remaining 
ones  differ  but  little  in  size  :  they  progressively 
diminish  towards  the  fifth. 

The  middle  phalanges  are  very  short,  but 
possess  pretty  nearly  the  same  general  characters 


as  the  metatarsal.  The  posterior  extremities 
are  articulated  with  the  last-named  phalanges 
by  means  of  an  articular  surface,  concave 
from  before  backwards  and  convex  transversely. 
The  articular  surface  on  the  anterior  extremity 
is  convex.  The  great  toe  is  deficient  in  the 
middle  phalanx;  they  diminish  in  size  from 
within  and  outwards.  They  have  been  com- 
pared to  the  pieces  of  the  coccyx,  but  may 
be  easily  distinguished  by  the  articular  surfaces. 

The  ungual  phalanges  (so  called  from  being- 
next  the  nail,  unguis)  are  five  in  number, 
and  decrease  in  size  from  the  first  to  the  fifth  ; 
that  belonging  to  the  first  very  much  exceeding 
the  rest  in  size.  The  posterior  extremity  of 
each  is  expanded,  and  has  an  articular  facet 
for  articulation  with  the  middle  phalanx.  The 
central  part  or  shaft  is  flattened,  slightly 
convex  on  its  dorsal  surface  :  its  anterior  ex- 
tremity is  still  more  flattened  and  slightly 
expanded,  presenting  a  thin  convex  margin. 
It  is  rough  on  its  inferior  surface  where  the 
dense  and  adipose  cellular  tissue  constituting 
the  pulp  of  the  toe  is  connected  with  it,  and 
on  its  superior  surface  it  is  smooth,  where 
the  nail  is  applied  upon  it.  • 

The  structure  and  mode  of  developement 
of  the  phalanges  are  pretty  much  the  same 
as  those  of  the  metatarsal  bones  :  their  complete 
ossification,  however,  takes  place  at  a  much 
later  period. 

For  the  modifications  in  the  number,  forms, 
and  arrangement  of  the  bones  cf  the  foot  in 
the  animal  series,  see  Osseous  system  (Comp. 
Anat.)  and  the  articles  on  the  various  classes. 

Joints  of  the  foot. — These  may  be  classed 
as  the  joints  of  the  tarsus,  metatarsus,  and 
toes. 

Joints  of  the  tarsus. — The  bones  constituting 
the  first  row  of  the  tarsus  are  connected  to- 
gether by  means  of  two  articulations,  one 
posterior,  the  other  anterior.  The  first  ( pos- 
terior astragulo -calcanien  articulation)  is 
formed  by  a  convex  oval  surface  on  the  os 
calcis,  which  is  received  into  a  deep  concavity 
on  the  astragalus.  A  synovial  sac  lines  these 
surfaces ;  the  posterior  part  of  this  sac  is 
covered  by  the  fatty  substance  which  is  placed 
between  the  back  of  the  ankle-joint  and  the 
tendo  Achillis,  and  on  the  removal  of  the  fat 
the  sac  is  observed  to  be  strengthened,  especially 
in  its  centre,  by  a  few  ligamentous  fibres. 
On  the  inner  side  this  sac  is  strengthened  by 
the  tendon  of  the  flexor  pollicis  proprius  and 
its  sheath  behind,  and  by  the  internal  lateral 
ligament  of  the  ankle-joint  in  front ;  both  of 
which  very  much  protect  the  articulation  and 
strengthen  the  union  of  the  bones.  Anteriorly 
there  are  no  proper  fibres  applied  upon  the 
synovial  membrane;  but  the  interosseous  liga- 
ment to  be  described  presently,  amply  supplies 
the  want  of  them.  On  the  outside  a  few 
ligamentous  fibres  are  applied  to  the  synovial 
membrane. 

The  anterior  astragalo-calcanien  articulation 
is  formed  by  a  slightly  convex  surface  on  the 
astragalus,  which  is  received  by  a  concavity 
on  the  upper  surface  of  the  sustentaculum  of 
the  os  calcis.    This  articulation  is  furnished 


BONES  OF  THE  FOOT. 


343 


with  a  synovial  membrane,  which  is  only  a 
prolongation  from  that  of  the  joint  between 
the  astragalus  and  scaphoid 

The  chief  bond  of  union  between  the  as- 
tragalus and  os  calcis  is  by  means  of  the 
inter-osseous  ligament  (apparatus  ligamentosus 
cavitatis  sinuosa,  Weitbr.):  this  ligament  oc- 
cupies the  hollow  which  is  manifest  on  the 
outside  between  the  os  calcis  and  the  neck 
of  the  astragalus.  It  consists  of  a  series 
of  strong  ligamentous  fibres,  which  arise  all 
along  the  inner  part  of  the  depression  on  the 
astragalus  in  a  curved  course,  and  descend 
vertically,  or  nearly  so,  to  be  inserted  into 
the  corresponding  depression  between  the  two 
articular  surfaces  on  the  os  calcis.  A  con- 
siderable quantity  of  fat  occupies  this  space, 
and  covers  this  ligament,  and  is  intermixed 
with  its  fibres. 

The  bones  forming  the  second  row  of  the 
tarsus  are  articulated  as  follows  : — 

The  scaphoid  or  navicular  bone  is  articulated 
with  the  three  cuneiform,  by  means  of  the 
triple  surface  already  described  on  the  former 
bone;  to  each  division  of  which  one  cuneiform 
is  adapted  (cuneo-scaphoid  articulation).  A 
common  synovial  membrane  lines  the  surface  on 
the  scaphoid,  the  surfaces  of  the  cuneiform  bones, 
and  passes  in  between  them  to  line  the  lateral 
articular  facets  on  the  latter  bones.  The  three 
cuneiform  bones  are  connected  to  the  navicular 
by  means  of  six  ligaments,  which  pass  from 
the  former  to  the  latter ;  three  on  the  dorsal 
surface  and  three  on  the  plantar.  The  dorsal 
ligament  of  the  internal  cuneiform  extends 
directly  from  behind  forwards,  those  of  the 
others  proceed  obliquely  forwards  and  out- 
wards. The  internal  cuneiform  has  likewise 
an  internal  ligament,  which  proceeds  from  its 
internal  part  directly  backwards  to  the  navi- 
cular; it  lies  above  the  tendon  of  the  tibialis 
posticus.  As  to  the  plantar  ligaments,  that 
of  the  internal  cuneiform  is  the  strongest :  it 
is  extended  between  the  tubercle  on  the  na- 
vicular bone  and  that  on  the  cuneiform,  and 
is  in  part  confounded  with  the  tendon  of  the 
tibialis  posticus,  which  sends  a  process  out- 
wards to  the  other  cuneiform  bones,  and 
strengthens  the  ligamentous  fibres  which  belong 
to  them. 

The  cuneiform  bones  are  articulated  to  each 
other  by  means  of  the  lateral  facets,  which 
are  lined  by  synovial  membrane  prolonged 
from  that  of  the  cuneo-scaphoid  articulation. 
Each  joint  is  strengthened  by  a  dorsal,  a 
plantar,  and  an  interosseous  ligament.  The  two 
former  are  extended  transversely  from  one 
cuneiform  bone  to  the  other,  the  dorsal  being 
considerably  the  stronger.  The  principal  bond 
of  union,  however,  is  by  the  interosseous  liga- 
ment, which  is  extended  between  the  non- 
articular  parts  of  the  lateral  surfaces  of  each 
cuneiform  bone. 

The  cuboid  bone  is  articulated  with  the 
external  cuneiform  ( cuboido-cuneen  articula- 
tion) in  a  manner  so  similar  to  that  by  which 
the  cuneiform  bones  are  articulated  with  each 
other  as  to  render  a  separate  description  super- 
fluous.   Its  synovial  membrane  is  continuous 


with  that  of  the  cuneo-scaphoid,  and  its  liga- 
ments are  precisely  similar  to  those  of  the 
cuneiform  articulations. 

The  cuboid  bone  is  united  to  the  scaphoid 
by  means  of  ligaments.  The  outer  extremity 
of  the  latter  bone  is  in  contact  with  a  small 
portion  of  the  inner  surface  of  the  former,  near 
its  posterior  superior  angle,  and  sometimes  a 
small  articular  facet  indicates  the  point  of  each 
bone  where  contact  is  established.  The  liga- 
ments which  pass  between  these  bones  under 
all  circumstances  are  a  dorsal  ligament,  directed 
obliquely  from  without  inwards,  a  plantar 
ligament,  transverse  and  very  thick,  and  an  in- 
terosseous ligament  extended  between  the  cor- 
responding surfaces  of  the  two  bones,  excepting 
where  the  facets  are  found,  when  they  exist. 

Articulation  of  the  two  rows  of  tarsal  bones 
to  each  other. — This  is  effected  by  means  of  the 
astragalus  and  os  calcis  behind,  and  the  scaphoid 
and  cuboid  in  front. 

Astragalo-scaphoid  articulation. — The  head 
of  the  astragalus  is  received  into  a  cavity  which 
is  in  greatest  part  formed  by  the  glenoid  cavity 
of  the  scaphoid  bone,  and  is  completed  infe- 
riorly  and  internally  by  a  ligament  (the  inferior 
calcuneo-scaphoid),  which  extends  from  the 
sustentaculum  of  the  os  calcis  to  the  inner  part 
of  the  inferior  surface  of  the  scaphoid.  On 
the  outer  side  and  inferiorly  the  head  of  the 
astragalus  is  supported  by  a  short  ligament 
(the  external  calcaneo-scaphoid )  which  is  at- 
tached posteriorly  to  the  inner  part  of  the  os 
calcis,  and  in  front  to  the  external  extremity  of 
the  scaphoid.  The  extension  of  the  recipient 
cavity  for  the  head  of  the  astragalus  by  means 
of  the  ligaments  just  named  was  rendered 
necessary  by  the  considerable  excess  in  the  size 
of  the  head  of  the  astragalus  over  the  glenoid 
cavity  of  the  scaphoid.  By  means  of  these 
ligaments,  too,  the  os  calcis  is  connected  with 
the  scaphoid,  although  there  is  no  articulation 
between  them. 

The  astragalo-scaphoid  articulation  is  strength- 
ened by  but  one  proper  ligament,  and  that  is 
situated  in  the  dorsal  aspect;  it  is  the  superior 
astragalo-scaphoid  ligament,  and  is  attached 
posteriorly  to  the  neck  of  the  astragalus,  and  in 
front  to  the  margin  of  the  glenoid  cavity ;  the 
transverse  extent  of  this  ligament  is  equal  to 
that  of  the  scaphoid  bone  on  its  dorsal  surface ; 
the  direction  of  its  fibres  is  forwards  and  out- 
wards. It  is  a  thin  fibrous  expansion,  covered 
superiorly  by  the  extensor  brevis  digitorum 
muscle,  and  on  its  inferior  surface  lined  by  the 
synovial  membrane  of  the  joint. 

Calcaneo-cuboid  articulation.- — The  articular 
surface  on  the  os  calcis  is  slightly  concave  in 
the  direction  from  above  downwards;  that  on 
the  cuboid  is  convex  in  the  same  direction. 
The  two  surfaces  are  closely  adapted  to  each 
other,  and  their  union  maintained  by  the  fol- 
lowing ligaments: — 1.  The  superior  or  dorsal 
calcaneo-cuboid  ligament,  which  consists  of  but 
a  few  fibres  extending  from  the  superior  and 
anterior  part  of  the  os  calcis  to  the  cuboid. 
2.  The  internal  calcaneo-cuboid  ligament,  a 
short,  strong,  quadrilateral  ligament  from  three 
to  four  lines  in  breadth,  placed  in  great  part 


344 


BONES  OF  THE  FOOT. 


over  the  superior  aspect  of  the  joint;  the  fibres 
pass  with  a  slight  obliquity  inwards  from  the  os 
calcis  to  the  cuboid.  3.  The  plantar  or  inferior 
calcaneo-cuboid  ligament,  the  strongest  and 
largest  of  the  foot  ligaments,  seems  destined 
not  alone  for  the  articulation  under  considera- 
tion, but  also  to  strengthen  the  arch  of  the 
tarsus  generally  on  its  plantar  surface.  It  is 
attached  behind  to  the  inferior  surface  of  the 
os  calcis,  commencing  from  the  angular  depres- 
sion between  the  two  tubercles.  After  leaving 
the  os  calcis  a  distinction  between  its  superficial 
and  deep  fibres  becomes  very  manifest;  the 
former  proceed  forwards  and  inwards,  pass 
under  the  cuboid  bone,  forming  an  adhesion  to 
the  posterior  lip  of  its  groove,  then  pass  under 
that  groove  and  its  contained  tendon,  and  are 
ultimately  inserted  into  the  posterior  extremities 
of  the  third  and  fourth  metatarsal  bones.  The 
deep  fibres  diverge  immediately  after  they  have 
left  the  os  calcis,  and  are  inserted  into  the  whole 
inferior  surface  of  the  cuboid  posterior  to  the 
groove. 

It  will  be  observed  that  the  two  joints  last 
described  lie  beside  each  other  in  the  same 
line,  a  circumstance  which  favours  the  surgical 
operation  of  partial  amputation  of  the  foot  in 
that  line.  Each  joint,  however,  has  its  proper 
synovial  membrane  lining  the  cartilaginous 
incrustations  of  the  bones  and  the  articular 
surfaces  of  the  ligaments;  that  of  the  astragalo- 
scaphoid  is  the  more  lax,  and  indicates  the 
existence  of  a  considerable  range  of  mot'on  in 
that  joint. 

Motions  of  the  tarsal  joints.  —  All  these 
joints  belong  to  the  class  Arthrodia,  some  of 
them  being  planiform.  The  motion  in  all  is 
that  of  simple  gliding,  limited  by  the  strength, 
number,  and  position  of  the  ligaments.  The 
close  inspection  of  the  bones  of  the  meta- 
tarsal row,  and  the  firm  ligamentous  bands 
which  pass  between  them,  occasion  a  very 
limited  mobility  of  the  bones  of  that  row. 
Between  the  astragalus  and  os  calcis,  on  the 
other  hand,  the  motions  are  much  more  mani- 
fest ;  these  are  gliding  motions  in  the  direction 
from  before  backwards  and  vice  versa,  or  from 
side  to  side.  When  the  foot  is  turned  inwards 
or  outwards  the  latter  motion  is  called  into 
play,  and  the  gliding  in  the  antero-posterior 
direction  takes  place  when  the  weight  of  the 
body  presses  on  the  foot,  causing  its  elongation 
and  the  diminution  of  the  curvature  of  its 
antero-posterior  arch.  When  the  weight  presses, 
the  astragalus  glides  forward  upon  the  os  calcis; 
when  the  weight  is  removed,  the  bone  returns 
to  its  former  condition  by  gliding  backwards. 

But  the  greatest  mobility  exists  in  the  articu- 
lation between  the  two  rows  of  tarsal  bones. 
There,  indeed,  the  principal  motions  of  the 
tarsus  take  place.  The  motions  of  the  foot, 
which  many  have  erroneously  attributed  to  a 
supposed  power  of  lateral  motion  in  the  ankle- 
joint,  really  take  place  in  this  line  of  articula- 
tion. When  the  foot  is  turned  so  that  its  sole 
is  directed  outwards,  the  scaphoid  glides  from 
above  downwards  on  the  head  of  the  astragalus, 
the  astragalus  glides  from  within  outwards  on 
the  os  calcis,  in  consequence  of  which  the 


hollow  space  between  the  last-named  bone  and 
the  neck  of  the  astragalus  is  diminished,  the 
interosseous  ligament  relaxed,  the  external 
lateral  ligament  of  the  ankle-joint  likewise 
relaxed,  and  the  internal  lateral  ligament  ren- 
dered tense.  On  the  other  hand,  when  the 
sole  of  the  foot  is  turned  inwards,  which  may 
be  done  much  more  completely  than  in  the 
opposite  direction,  the  scaphoid  glides  from 
below  upwards  upon  the  head  of  the  astragalus, 
the  inferior  surface  of  the  os  calcis  is  turned 
inwards,  the  astragalus  glides  upon  the  last- 
named  bone  from  without  inwards,  enlarging 
the  interosseous  space,  stretching  the  ligament 
which  occupies  that  space,  and  also  rendering 
tense  the  external  lateral  ligaments  of  the  ankle- 
joint.  It  is  therefore  natural  to  expect,  as 
Bichat  has  remarked,  that  in  those  sprains 
which  result  from  too  great  inversion  or  eversion 
of  the  foot,  the  ligaments  of  the  articulations 
between  the  tarsal  rows  should  suffer  most. 

Tarso-metatarsal  articulations. — The  plane 
surface  on  the  wedge-shaped  tarsal  extremity  of 
each  metatarsal  bone  is  applied  to  correspond- 
ing plane  surfaces  on  the  cuneiform  bones  and 
the  cuboid.  The  first,  second,  and  third  meta- 
tarsal bones,  counting  from  within  outwards, 
are  articulated  with  the  first,  second,  and  third 
cuneiforms,  and  the  fourth  and  fifth  with  the 
cuboid;  the  second  metatarsal,  however,  is 
additionally  articulated  with  the  first  and  third 
cuneiforms,  by  its  lateral  surfaces  being,  as  it 
were,  mortised  into  a  cavity  formed  by  these 
three  bones,  and  each  of  the  other  metatarsal 
bones  is  articulated  with  its  fellow  on  each  side 
of  it.  These  articulations  have  the  following 
common  characters :  they  are  planiform  arthro- 
dia?, each  articular  surface  is  covered  by  a  thin 
layer  of  cartilage,  and  they  all  have  ligaments 
similarly  arranged  in  two  sets,  dorsal  and 
plantar. 

The  first  tarso-metatarsal  articulation  has  a 
greaterextent  of  its  articular  surfaces  than  those 
of  the  others.  Its  plantar  ligament  is  of  great 
strength  and  extends  from  the  great  cuneiform, 
directed  obliquely  forwards  and  outwards  to 
the  first  metatarsal  bone,  continuous  posteriorly 
with  the  cuneo-scaphoid  ligament,  and  strength- 
ened by  fibres  from  the  tendon  of  the  tibialis 
posticus,  and  on  the  outside  by  fibres  from  the 
tendon  of  the  peroneus  longus.  The  dorsal 
ligament  consists  of  short  and  parallel  fibres  ;  its 
breadth  is  equal  to  that  of  the  cuneiform  bone ; 
it  is  a  weak  and  membranous  ligament.  This 
articulation  has  a  synovial  membrane  distinct 
from  that  of  the  other  tarso-metatarsal  joints. 

The  second  tarso-metatarsal  articulation  is 
the  most  solid  of  all,  from  the  fact  of  the  pos- 
terior extremity  of  the  metatarsal  bone  being 
fitted  into  the  mortise-shaped  cavity  formed  by 
the  cuneiform  bones.  Its  ligaments,  it  may 
naturally  be  expected,  are  more  complicated 
than  those  of  the  other  joints  of  this  row  ;  thus 
it  has  three  dorsal  ligaments,  a  middle  one, 
possessing  common  characters  with  those  of  the 
other  joints,  proceeding  directly  from  behind 
forwards  from  the  second  cuneiform  to  the 
second  metatarsal  bone;  the  others  are  ex- 
tended,  one  from    the   internal  cuneiform 


BONES  OF  THE  FOOT. 


345 


obliquely  outwards  to  the  second  metatarsal, 
the  other  from  the  third  cuneiform  obliquely 
inwards  to  the  same  bone.  We  find,  moreover. 
two  plantar  ligaments,  one  short  and  direct, 
passing  from  the  second  cuneiform  bone  to  the 
second  metatarsal,  the  other  much  longer  and 
more  oblique,  coming  from  the  first  cuneiform. 
Lastly,  this  articulation  has  an  interosseous  liga- 
ment, which  is  extended  from  the  lateral  facet 
on  the  external  surface  of  the  first  cuneiform  to 
a  corresponding  one  on  the  internal  surface  of 
the  second  cuneiform. 

Each  of  the  remaining  tarso-metatarsal  arti- 
culations has  its  dorsal  ligaments,  of  which 
those  of  the  third  and  fourth  are  direct,  and  that 
of  the  fifth  is  extended  obliquely  outwards 
from  the  cuboid  to  the  fifth  metatarsal  bone. 
In  all  three,  the  place  of  plantar  ligament  is 
supplied  by  the  sheath  of  the  long  peroneal 
tendon,  and  the  fifth  receives  additional  strength 
from  fibres  given  off  from  the  tendon  of  the 
peroneus  brevis.  In  the  third  there  is  an 
interosseous  ligament  between  the  third  and 
fourth  metatarsal  bones,  and  from  the  anterior 
part  of  the  external  surface  of  the  third  cunei- 
form to  the  fourth  metatarsal. 

The  five  tarso-metatarsal  articulations  have 
four  synovial  membranes  amongst  them  :  the 
first,  as  has  already  been  mentioned,  has  a 
distinct  one  ;  the  second  lines  the  contiguous 
surfaces  of  the  first  and  second  cuneiform  bones, 
and  is  prolonged  over  the  mortise-shaped  cavity 
and  the  articular  portions  of  the  second  meta- 
tarsal. The  third  lines  the  articular  portions 
of  the  third  cuneiform  and  third  metatarsal, 
and  is  prolonged  on  either  side  of  the  latter  in 
the  form  of  two  culs-de-sac  into  the  space 
between  the  latter  bone  and  the  second  meta- 
tarsal on  the  inside,  and  the  fourth  on  the 
outside.  In  fine,  the  fourth  synovial  membrane 
is  common  to  the  fourth  and  fifth  tarso-meta- 
tarsal joints. 

Metatarsal  articulations. — The  four  external 
metatarsal  bones  are  articulated  with  each  other 
by  means  of  the  contiguous  articular  facets  on 
the  lateral  surfaces  of  their  posterior  extremi- 
ties. They  are  maintained  in  apposition  by 
interosseous  ligaments  which  pass  from  one 
metatarsal  bone  to  the  other,  being  inserted 
into  rough  surfaces  immediately  above  the 
articular  portion  of  each  bone.  Moreover, 
these  joints  have  dorsal  and  plantar  ligaments, 
which  consist  of  ligamentous  fibres  directed 
transversely  from  one  bone  to  the  other.  The 
plantar  ligaments  are  considerably  stronger  and 
thicker  than  the  dorsal. 

The  anterior  extremities  of  the  five  meta- 
tarsal bones,  although  not  articulated  together 
by  surfaces  which  play  upon  each  other,  are 
yet  connected  by  a  common  transverse  ligament 
which  passes  from  one  bone  to  ttye  other,  being 
attached  to  the  plantar  surface  of  each  bone, 
and  covered  by  the  sheaths  of  the  flexor  ten- 
dons. 

Metatarso-phalangeal  articulations.  —  The 
convex  articular  surface  of  the  anterior  extre- 
mity of  each  metatarsal  bone  is  adapted  to  the 
concave  surface  on  the  posterior  extremity  of 
each  posterior  or  metatarsal  phalanx.    A  sepa- 


rate synovial  membrane  lines  the  articular  sur- 
faces of  each  joint ;  and  two  lateral  ligaments, 
one  on  either  side,  maintain  the  surfaces  in 
apposition.  On  the  dorsal  aspect  each  joint  is 
strengthened  and  protected  by  the  extensor 
tendons ;  and  on  the  plantar  a  strong,  thick, 
almost  cartilaginous  substance  is  extended 
from  the  metatarsal  bone  to  the  phalanx.  This 
substance  protects  the  joint  inferiorly ;  it  is 
grooved  on  its  inferior  surface,  and  contributes 
to  form  the  sheath  for  the  flexor  tendon,  which 
runs  along  the  plantar  surface  of  each  toe. 

The  metatarso-phalangeal  articulation  of  the 
great  toe  presents  some  points  of  difference 
from  the  others  ;  its  surfaces  are  more  exten- 
sive, and  on  the  plantar  aspect  the  head  of  the 
metatarsal  bone  has  a  pulley-like  form,  from 
the  existence  of  a  ridge  in  its  centre,  on  either 
side  of  which  there  is  a  superficial  depression  : 
each  depression  receives  a  sesamoid  bone, 
which,  being  formed  in  the  substance  of  the 
inferior  ligament,  thus  contributes  greatly  to 
strengthen  the  joint  in  this  situation. 

Articulations  of  the  toes. — These  are  gin- 
glymoid  joints,  all  closely  resembling  each 
other  both  in  the  forms  of  the  articular  surfaces, 
and  also  in  the  bonds  of  union  by  which  the 
contiguity  of  these  surfaces  is  maintained. 
The  articular  surfaces  are  pulley-like;  an  in- 
ternal and  an  external  lateral  ligament  belong  to 
each  joint ;  and  the  plantar  aspect  of  each  is 
protected  by  a  ligamentous  structure  similar  to 
that  already  described  in  the  metatarso-phalan- 
geal joints. 

Motions  of  the  metatarsal  joints. — At  the 
tarsal  extremities  the  metatarsal  bones  enjoy 
but  a  very  limited  mobility  in  consequence  of 
the  strong  and  compact  manner  in  which  they 
are  articulated  with  the  tarsus  ;  their  motions 
consist  in  a  very  limited  and  scarcely  percepti- 
ble gliding  upwards  and  downwards.  At  their 
phalangeal  extremities,  however,  the  metatar- 
sal bones  are  capable  of  a  greater,  although 
still  a  very  limited,  degree  of  motion. 

Motions  of  the  metatarso-phalangeal  joints. 
— These  are  flexion  and  extension,  with  a  slight 
degree  of  lateral  inclination  or  abduction  and 
adduction,  and  also,  of  course,  circumduction 
or  the  rapid  succession  of  the  preceding  four. 
The  lateral  motions  are  very  limited,  being 
most  manifest  in  the  joint  of  the  great  toe. 
Flexion  is  limited  by  the  extensor  tendon  and 
the  superior  fibres  of  the  lateral  ligaments; 
extension  by  the  inferior  fibres  of  the  lateral 
ligaments,  by  the  inferior  ligament,  and  by 
the  flexor  tendon. 

Motions  of  the  phalangeal  joints. — Flexion 
and  extension  only  are  enjoyed  by  these  joints, 
the  extent  of  which  is  principally  controlled 
by  the  lateral  ligaments  and  by  the  due  anta- 
gonism of  the  flexor  and  extensor  muscles. 

Vie  wing  the  human  foot  as  a  whole,  we 
cannot  fail  to  notice  how  admirably  it  is 
adapted  as  an  instrument  of  support,  and  for 
the  purposes  of  progression.  For  the  former 
end  the  solid  and  yet  elastic  mechanism  of 
the  tarsus  is  mainly  useful  ;  this  part  is  placed 
immediately  under  the  tibia,  which  transmits 
the  weight  of  the  body  to  the  astragalus,  the 


346 


BONES  OF  THE  FOOT. 


highest  bone  of  the  tarsus;  from  this  bone, 
again,  the  weight  is  transmitted  to  the  os 
calcis  in  the  backward  direction,  and  to  the 
anterior  row  of  tarsal  bones  in  front,  where 
the  transverse  extent  of  the  tarsus  is  consider- 
ably increased,  in  order  to  enlarge  the  basis  of 
support.  It  is  worthy  of  remark  that  the 
solidity  of  the  anterior  part  of  the  tarsus  is  less 
on  its  inner  than  on  its  outer  side,  the  effect  of 
which  is  to  increase  the  elasticity  of  the  former 
part  without  materially  diminishing  its  strength. 
The  object  of  this  arrangement  appears  to  be  ex- 
plained by  the  observation  that  the  weight  of  the 
body  is  transmitted  by  the  astragalus  principally 
to  the  inner  side  of  the  tarsus.  It  is  toward  the 
inner  side  also  that  the  concavity  of  the  under 
surface  of  the  tarsus  is  most  evident,  by  which 
not  only  can  the  sole  of  the  foot  adapt  itself 
to  the  irregularities  of  surface  to  which  ,it  is 
applied,  but  it  is  enabled  to  yield  under  the 
superincumbent  weight,  and  so  to  counteract 
the  effects  of  sudden  concussion  in  walking, 
leaping,  &c. 

In  the  foot  anatomists  have  described  two 
arches  as  connected  with  its  mechanical  arrange- 
ments. The  first  is  best  seen  in  a  profile  view 
of  the  foot ;  it  is  termed  the  antero-posteripr 
arch  ;  upon  this  arch  we  rest  when  the  toes  are 
applied  to  the  ground,  the  posterior  extremity 
of  it  being  the  heel,  the  anterior  the  balls  of  the 
toes,  and  the  astragalus  resembling  the  key- 
stone of  the  arch.  The  second  is  the  transverse 
arch,  which  may  be  most  satisfactorily  demon- 
strated by  a  transverse  section  made  along  the 
line  of  the  cuneiform  bones.  The  effect  of  the 
constant  and  violent  exercises  of  the  foot  to 
which  public  dancers  are  accustomed  is  to  in- 
crease the  mobility  of  the  different  parts  of  the 
foot,  to  an  extent  which  unfits  it,  in  a  great 
measure,  for  its  office  as  an  instrument  of  sup- 
port in  standing  or  walking,  as  may  be  ob- 
served, says  Sir  C.  Bell,  in  any  of  the  retired 
dancers  and  old  figurantes.  By  standing  so 
much  on  the  toes,  he  adds,  the  human  foot  is 
converted  to  something  more  resembling  that 
of  a  quadruped,  where  the  heel  never  reaches 
the  ground,  and  where  the  paw  is  nothing  more 
than  the  phalanges  of  the  toes. 

The  following  considerations  connected  with 
the  human  foot  may  be  quoted  as  so  many  in- 
dications that  the  erect  attitude  is  natural  to 
man:  1.  the  articulation  of  the  foot  at  right 
angles  with  the  leg;  2.  the  great  comparative 
size  of  the  foot,  contrasted  with  that  of  other 
animals ;  3-  the  great  transverse  extent  of  the 
foot ;  4.  the  predominance  of  its  solid  parts, 
the  tarsus  and  metatarsus,  over  its  moveable 
part,  the  phalanges  ;  5.  the  direction  of  the  me- 
tatarsal bone  supporting  the  great  toe;  its  situa- 
tion and  want  of  mobility ;  6.  the  limited  mo- 
bility of  the  phalanges  of  the  foot  as  compared 
with  those  of  the  fingers;  7.  the  horizontal  po- 
sition of  the  os  calcis  ;*  the  excess  of  its  trans- 

*  "  Even  the  Simiae  and  the  bear,"  says  Mr. 
Lawrence,  "  have  the  end  of  the  os  calcis  raised, 
so  that  this  bone  begins  to  form  an  acute  angle  with 
the  leg;  the  dog,  the  cat,  and  other  digitated 
quadrupeds,  even  the  elephant  himself,  do  not  rest 
on  the  tarsus  or  carpus,  but  merely  on  the  toes  ; 


verse  extent  at  its  posterior  over  that  of  its  an- 
terior part,  and  the  developement  of  its  tuber- 
cles ;  8.  the  great  strength  and  developement 
of  the  calcaneo-cuboid  ligament;  9.  the  early 
ossification  of  the  bones  of  the  foot  as  compared 
with  those  of  the  hand. 

The  extraordinary  extent  to  which  art  can 
modify  the  positions  of  the  several  bones,  and 
the  form  of  the  whole  foot,  is  remarkably  ex- 
emplified in  the  case  of  the  Chinese  foot.  It 
is  well  known  that,  among  other  barbarities 
practised  on  Chinese  females,  their  feet  are 
from  an  early  period  subjected  to  the  most 
violent  pressure,  with  the  view  of  reducing  them 
to  that  diminutive  size  which  is  esteemed  a 
point  of  great  beauty.  Hence  the  anatomical 
examination  of  a  foot  thus  compressed  is  a 
point  of  great  interest,  not  alone  to  the  physio- 
logist, but  also  to  the  surgeon,  as  indicating 
what  properly  applied  force  may  do  when  em- 
ployed at  a  sufficiently  early  period.  An  inte- 
resting account  of  such  an  examination  was 
communicated  in  the  year  1829  to  the  Royal 
Society  by  Mr.  Bransby  Cooper,  from  whose 
paper  we  extract  the  following  statements. 

The  foot  at  first  view  had  the  appearance  of 
being  congenitally  deformed ;  it  was  remarka- 
bly short ;  from  the  heel  to  the  great  toe  its 
measurement  did  not  exceed  five  inches;  it  was 
very  much  contracted  in  its  transverse  dimen- 
sions, and  the  instep  extremely  high,  being  un- 
usually convex  not  only  from  before  backwards, 
but  also  from  side  to  side. 

"  The  position  of  the  os  calcis,"  to  use  Mr. 
B.  Cooper's  words,  "  is  very  remarkably  altered : 
instead  of  the  posterior  projection  which  usually 
forms  the  heel,  a  straight  line  is  preserved  in 
this  direction,  not  deviating  from  the  line  of  the 
tibia;  and  the  projecting  point  which  forms  in 
an  ordinary  foot  the  most  posterior  process  into 
which  the  tendo  Achillis  is  inserted,  touches 
the  ground,  and  becomes  the  point  d'appui  for 
sustaining  the  whole  weight  of  the  body.  The 
articular  surface  of  the  os  calcis  in  connexion 
with  the  cuboid  bone  is  about  half  an  inch  an- 
terior to  and  two  inches  above  this  point ; 
while  the  astragalar  joint  is  behind  and  some- 
what below  the  calco-cuboidal  articulation ; 
consequently  the  direction  of  the  os  calcis,  (in 
its  long  axis,)  instead  of  being  from  behind  for- 
wards, is  from  below  upwards,  with  the  slightest 
possible  inclination  forwards.  The  most  pro- 
minent parts  of  the  instep  are  the  round  head 
of  the  astragalus  and  the  cuboidal  articulation 
of  the  os  calcis.  From  this  the  remaining 
tarsal  bones  slope  downwards  at  nearly  a  right- 
angular  inclination  to  join  the  metatarsal  bones, 
whose  obliquity  is  still  downwards,  until  they 
rest  on  their  phalangeal  extremities." 

The  points  of  support  are  the  os  calcis,  the 
anterior  extremity  of  the  metatarsal  bone  of  the 
great  toe,  and  the  dorsal  surface  of  the  fourth 
and  fifth  toes,  which  are  bent  under  the  foot  so 
as  to  press  the  ground  at  this  part. 

(R.  B.  Todd.) 

the  cloven-hoofed  ruminants  and  the  Solipeda  touch 
the  ground  merely  with  the  extremities  of  the  third 
phalanges,  and  the  os  calcis  is  raised  nearly  into  a 
perpendicular  position." 


ABNORMAL  CONDITIONS  OF  THE  FOOT. 


347 


FOOT,  ABNORMAL  CONDITIONS  OF 
THE. — The  dislocation  of  any  of  the  bones  of 
the  foot  is  an  accident  of  unfrequent  occur- 
rence, particularly  of  the  tarsus  and  metatarsus, 
where  the  ligaments  are  powerful,  and  the  joints 
very  limited  in  their  motions.  When  a  dis- 
placement does  occur  here,  the  violence  neces- 
sary to  produce  it  is  often  so  great,  that  the 
foot  is  destroyed .  Cases,  however,  are  met  with 
where  a  dislocation  of  one  or  more  of  these 
bones  has  been  successfully  treated  without  loss 
of  the  limb.  Sir  A.  Cooper  mentions  several 
instances.  The  astragalus  alone,  without  the 
other  bones  of  the  foot,  is  never  thrown  back- 
wards, nor  is  it  ever  thrown  directly  inwards 
nor  directly  outwards,  but  it  may  be  dislocated 
forwards  on  the  instep  and  then  may  incline 
inwards,  so  as  to  be  situated  below  and  in  front 
of  the  inner  malleolus,  or  it  may  incline  out- 
wards and  be  placed  below  and  in  front  of  the 
outer  malleolus  ;  the  rest  of  the  foot  in  the 
latter  case  is  thrown  inwards,  and  in  the  former 
outwards. 

In  these  cases  there  is  what  Boyer  calls  a 
double  luxation  of  the  astragalus,  for  this  bone 
is  not  only  expelled  by  violence  from  the  mor- 
tise-shaped cavity  formed  for  it  by  the  bones 
of  the  leg,  but  is  at  the  same  time  driven  from 
the  space  formed  between  the  os  calcis  and  os 
naviculare,  where  it  naturally  rests  or  plays  in 
standing  or  progression. 

Most  of  the  ligamentary  ties  which  bind  it 
to  the  other  bones  of  the  foot  and  leg  are  vio- 
lently ruptured,  yet  in  these  cases  the  surgeon 
almost  invariably  finds  great  difficulty  in  ex- 
tracting the  bone  from  its  new  situation,  and  to 
return  it  back  to  its  original  space  in  general  is 
quite  impracticable. 

One  reason  for  the  difficulty  the  surgeon 
experiences  in  replacing  the  luxated  astragalus 
may,  we  imagine,  be  found  in  this,  that  the 
bones  once  expelled  by  violence,  the  muscles 
attached  to  the  tendo  Achillis,  and,  indeed, 
all  those  of  the  leg  before  and  behind,  act  so 
on  the  foot  as  to  have  a  powerful  and  effective 
influence  in  effacing  the  interspace  between  the 
os  calcis  and  articulating  surfaces  of  the  tibia 
and  fibula,  so  that  there  is  now  no  room  for 
its  return. 

Moreover,  it  should  be  recollected  that  the 
astragalus  is  sometimes  only  partially  luxated, 
and  perhaps  at  the  same  time  has  revolved  on 
its  long  axis  in  such  a  way  that  it  shall  be 
placed  as  it  were  on  its  side,  as  we  have  known 
an  example,  in  which  the  pulley-shaped  sur- 
face of  the  astragalus  looked  outwards,  the 
peroneal  articular  surface  looked  downwards 
towards  the  os  calcis,  and  the  facet  for  arti- 
culation with  the  tibial  malleolus  was  placed 
upwards  in  contact  with  that  part  of  the  tibia 
which  was  naturally  shaped  for  articulation  with 
the  upper  part  of  the  trochlea  of  the  astra- 
galus :  when  the  astragalus  is  thus  rotated  on 
its  longitudinal  axis,  a  broader  part  of  the  bone 
is  wedged  in  between  the  tibia  and  os  calcis 
than  the  vertical  height  of  the  astragalus  would 
measure,  and  hence  there  is  difficulty  in  re- 
storing the  bone  or  removing  it.  Fig.  161  re- 
presents the  simple  dislocation.    More  than 


one  example  is  mentioned  by  Sir  A.  Cooper 
in  which  this  bone  was  removed  entire  after  a 
compound  dislocation  of  it,  and  yet  a  very 
tolerable  use  of  the  foot  was  regained. 

A  heavy  weight  falling  upon  the  foot  will 
sometimes  displace  the  double  articulation  be- 
tween the  first  and  second  row  of  tarsal  bones. 
When  this  accident  has  occurred,  the  appear- 
ance which  the  limb  assumes  bears  a  striking- 
resemblance  to  the  internal  variety  of  the  club- 
foot. In  fact  this  state  of  the  parts  really  con- 
stitutes neither  more  nor  less  than  the  pied-bot, 
with  the  exception  of  the  difference  of  the 
cause,  the  state  of  ligamentous  connections, 
and  the  facility  of  reduction. 

Dislocation  of  the  other  tarsal  bones  is  very 
rare,  yet  Sir  A.  Cooper  has  seen  '  the  inner 
cuneiform  bone  displaced  in  two  instances,  in 
neither  of  which  could  the  bones  be  reduced. 
See  also  Diet,  des  Sciences  Medicales,  art. 
Pied. 

The  joints  of  the  toes,  as  they  are  more 
moveable  and  their  ligaments  more  lax,  are 
more  easily  dislocated  than  the  other  joints  of 
the  foot,  and  especially  the  great  toe,  which 
has  more  extent  of  motion  than  the  rest,  and  is 
more  exposed  to  the  influence  of  accident. 

Congenital  displacement  of  the  bones  of  the 


348 


ABNORMAL  CONDITIONS  OF  THE  FOOT. 


foot  is  by  no  means  an  uncommon  occurrence, 
and  though  in  our  English  systematic  works 
on  surgery  this  case  has  met  with  little  notice, 
yet,  as  a  subject  of  great  importance  to  the 
comfort  and  well-being  of  a  numerous  class  of 
sufferers,  it  is  by  no  means  undeserving  of  a 
place  in  a  professed  work  on  surgery.  As, 
however,  the  scope  of  the  present  is  not  strictly 
surgical,  we  shall,  in  this  article,  content  our- 
selves with  a  pathological  description  of  the 
principal  varieties  of  these  deformities,  and  in 
doing  this  we  shall  freely  avail  ourselves  of  the 
assistance  of  an  able  article  on  the  "  Pied-bot," 
by  Bouvier,  in  the  Diet,  de  Medecine  et  de 
Chirurgie  Pratiques. 

The  ankle-joint  is  not  generally  implicated 
in  congenital  deformities  of  the  foot ;  displace- 
ment of  the  bones  may  occur  to  an  extreme 
degree,  and  yet  the  natural  form  and  functions 


of  the  ankle  remain.  But  this  rule  is  by  no 
means  universal.  The  ankle-joint  may  be  the 
sole  seat  of  the  unnatural  condition,  or  it  may 
share  it  in  common  with  the  bones  of  the  foot; 
but  these  cases  are  rare,  they  form  only  the  ex- 
ception to  the  general  rule.  There  are  three 
principal  forms  of  distortion  to  which  the  foot 
is  congenitally  subject :  \.  when  the  foot  is 
turned  inwards,  which  has  been  termed  varus : 

2.  when  it  is  turned  outwards,  called  valgus: 

3.  when  the  foot  is  permanently  extended, 
and  the  patient  can  only  put  the  toes  to  the 
ground,  termed  pes  equinus.  Almost  all  the 
varieties  of  club-foot  may  be  referred  to  one  of 
these  species. 

1.  When  the  foot  is  turned  inwards,  (varus,) 
the  following  modifications  in  the  form  of  the 
parts  present  themselves.  (See  Jigs.  162,  163.) 
The  dorsum  faces  forwards,  the  sole  is  turned 


Fig.  162,  163. 


backwards,  and  very  considerably  curved  upon 
itself.  The  inner  side  of  the  foot  is  uppermost, 
the  outer  side  rests  upon  the  ground,  the  heel 
is  more  or  less  turned  inwards  and  upwards. 
The  integuments  of  the  outer  side  are  thickened 
by  pressure,  and  there  is  a  sort  of  provisional 
cushion,  of  a  somewhat  elastic  nature,  formed 
under  it,  while  the  thickness  and  hardness  of 
the  integuments  of  the  sole  are  not  found  to 
the  usual  degree.  The  joints  that  suffer  most 
in  this  malformation  are,  as  might  be  expected 
from  a  review  of  their  natural  structure,  the 
double  articulations  between  the  first  and  second 
row  of  tarsal  bones.  The  scaphoid  bone  is 
twisted  inwards  in  such  a  manner,  that  the 
dorsum  of  it  presents  forwards  and  its  apex 
backwards,  and  the  navicular  cavity  is  brought 
to  the  inner  edge  of  the  astragalus.  The  cuboid 
bone  generally  preserves  its  relation  to  the 
scaphoid,  being  more  or  less  displaced  from 
the  os  calcis,  and  turned  under  the  foot.  The 
cuneiform  bones,  the  metatarsus,  and  toes,  are 
little  altered  in  their  relation  to  those  tarsal 
bones  to  which  they  join,  the  peculiarity  of 
their  position  and  direction  being  entirely  the 
result  of  the  alterations  in  the  scaphoid  and 


cuboid,  just  mentioned.  The  os  calcis  is 
turned,  so  that  its  outer  side  is  inclined  to- 
wards the  ground,  and  further  than  natural 
from  the  outer  malleolus ;  the  inner  hollow  side 
is  inclined  upwards  and  inwards,  and  nearer  to 
the  inner  malleolus  than  natural,  and  the  heel 
itself  is  elevated.  By  this  means  the  articula- 
tions between  this  bone  and  the  astragalus  are 
altered  somewhat,  particularly  if  the  ankle-joint 
itself  remains  natural,  the  astragalus  not  having 
partaken  of  the  general  malposition  ;  this  bone 
is  then  thrown  in  some  degree  upon  the  outer 
side  of  the  os  calcis.  The  astragalus,  we  have 
said,  rarely  shares  in  the  general  deformity; 
when  it  does  it  is  tilted  outwards,  so  that  its 
upper  surface  inclines  towards  the  external 
malleolus,  and  the  articular  portion  itself  be- 
comes altered  in  form,  as  is  also  the  corre- 
sponding portion  of  the  tibia ;  in  one  instance  re- 
lated by  Bouvier,  the  astragalus,  by  the  pressure 
of  the  inner  side  of  the  tibia  above  and  of  the 
calcis  below,  was  reduced  to  a  mere  thin  edge 
on  this  side,  the  whole  bone  being  something 
in  form  of  a  wedge  between  them.  * 

2.  In  the  valgus,  (see  Jig.  164),  where  the 
foot  is  turned  in  the  opposite  direction  to  that 


ABNORMAL  CONDITIONS  OF  THE  FOOT. 


349 


Fig.  164. 


which  has  been  just  described,  the  whole  state 
of  the  foot  seems  to  be  pretty  nearly  the  exact 
converse  of  every  thing  there  mentioned.  The 
same  bones  are  affected,  and  in  the  same  rela- 
tive degree  ;  and  the  same  analogy  which  exists 
between  the  one  condition  and  the  phenomena 
of  adduction,  is  found  between  the  other  and 
those  of  abduction.  The  dorsum  faces  more 
or  less  directly  forwards,  the  plantar  surface 
backwards,  the  inner  side  of  the  foot  rests  upon 
the  ground,  the  outer  is  uppermost.  The  tibia 
frequently  here  participates  in  the  deformity  so 
far  as  to  have  a  curve  inwards,  and  the  inner 
ankle  consequently  approaches  to  the  ground. 
The  double  articulation  between  the  first  and 
second  row  of  bones  in  this  case  also  suffers 
the  most.  The  astragalus  sometimes  projects 
in  front,  and  lower  than  in  the  varus.  The 
distortion  is  sometimes  carried  to  such  an  ex- 
tent that  the  foot  is 
turned  nearly  upwards 
and  at  the  side  of  the 
fibula.  The  os  calcis 
is  twisted  outwards, 
with  the  heel  elevated, 
its  hollow  inclining  to- 
wards the  ground.  The 
scaphoid  and  cuboid 
bones  are,  as  we  have 
said,  most  displaced; 
the  first  being  nearest 
the  ground,  the  last 
placed  uppermost,  and 
near  the  outer  malleo- 
lus. The  cuneiform 
bones,  and  the  other 
bones  of  the  foot,  retain 
their  relation  to  the 
bones  to  which  they 
are  articulated,  their 
unnatural  situation  be- 
ing the  result  of  the 
displacement  of  these. 

3.  The  pes  equinus, 
(see  fig.165,)  so  named 
fromtheresemblance  in 
the  position  of  the  tar- 
sus to  that  of  the  horse, 


differs  from  either  of  the  others  in  its  anato- 
mical characters.  When  it  has  arrived  at  a  con- 
siderable pitch,  the  tibia  is  found  partially  dislo- 
cated backwards  upon  the  os  calcis;  the  sca- 
phoid and  cuboid  are  carried  backwards,  to- 
wards the  sole  of  the  foot,  leaving  the  upper 
part  of  the  head  of  the  astragalus  and  cuboides 
projecting;  the  cuneiform  and  metatarsal  bones 
are  displaced  sometimes  in  a  similar  manner. 
Thus  the  whole  foot  is  more  arched  than 
natural,  independently  of  its  altered  position ; 
the  sole  is  shortened  and  hollowed,  the  dorsum 
is  elongated  and  projecting. 

A  very  interesting  history  of  yet  another  form 
of  this  disease  by  M.  Holz  of  Strasburg,  is 
given  in  the  13th  vol.  of  the  Lancet,  in  which 
the  foot  was  turned  completely  back,  having 
the  dorsum  resting  on  the  ground,  the  plantar 
surface  being  uppermost.  The  deformity  was  in 
both  feet.  Walking  was  not  painful ;  the  patient 
rested  his  weight  on  the  tarsus ;  the  metatarsus 
and  toes  did  not  touch  the  ground.  He  wore 
common  half-boots,  the  toes  of  which  pointed 
backwards  and  the  heels  forwards.  The  man 
died,  and  upon  examination  of  his  feet  the  fol- 
lowing state  of  parts  was  found.  The  skin  of 
the  dorsum  upon  which  he  trod  was  hard  and 
callous.  The  bones  of  the  leg  were  well 
formed  ;  the  astragalus  was  dislocated  forwards; 
the  calcaneum  forwards  and  outwards,  and  the 
cuboid  downwards  on  the  calcaneum.  The 
dorsal  surface  of  the  foot  was  very  convex,  ex- 
cepting at  the  spot  which  touched  the  ground  ; 
the  plantar  surface  very  concave.  The  supe- 
rior articular  surface  of  the  astragalus  was 
turned  directly  forward  and  a  little  downward  ; 
its  posterior  surface  also  looked  forward,  and 
the  tibia  rested  on  the  inferior,  in  a  great  de- 
gree, and  on  the  small  process  of  the  calca- 
neum. The  connexion  of  the  scaphoid  with 
the  astragalus  was  more  natural ;  the  scaphoid 
was,  however,  turned  a  little  backward.  The 
cuboid  rested  by  its  posterior  part  on  the  inferior 
surface  of  the  os  calcis.  The  articular  surfaces 
of  the  astragalus  and  os  calcis  gave  attachment 
to  ligamentous  fibres.  The  three  cuneiform 
bones,  the  metatarsal  bones,  and  the  toes  had 
not  experienced  any  sensible  change  in  their 
position. 

The  descriptions  now  given  are  of  extreme 
cases  in  each  of  the  species  of  deformity.  Of 
course  the  degree  of  departure  from  the  natural 
form  varies  in  every  case.  In  the  varus,  every 
intermediate  shade  between  the  extreme  men- 
tioned and  the  mere  state  of  permanent  adduc- 
tion occurs.  The  state  of  fixed  abduction  may, 
in  the  same  way,  be  called  the  milder  extreme 
of  the  valgus,  while  the  pes  equinus  shows  its 
simplest  form  in  the  mere  fixed  extension  of 
the  foot. 

We  also  find  in  some  instances  a  combina- 
tion of  more  than  one  form  of  the  deformity  in 
the  same  foot.  The  most  frequent  of  these  is  the 
state  of  permanent  extension,  of  the  pes  equinus, 
with  the  adduction  of  the  metatarsal  bones  and 
phalanges,  constituting  a  variety  of  the  varus. 
(Fig.  166.)  The  same  complication  of  the 
pes  equinus  with  the  valgus  is  rare,  but  does 
sometimes  occur.    A  congenital  deformity,  so 


350 


ABNORMAL  CONDITIONS  OF  THE  FOOT. 


Fig,  166.  far  as  we  know  not 

mentioned,  has  once 
fallen  under  our  no- 
tice, namely,  a  dislo- 
cation of  the  tibia  back- 
wards upon  the  upper 
and  posterior  part  of 
the  os  calcis,  so  that  the 
prominence  of  the  heel 
was  entirely  lost,  and 
the  foot  flexed  to  such 
a  degree,  as  that  the 
dorsum  lay  in  contact 
with  the  anterior  part 
of  the  leg. 

The  alterations  from 
the  normal  state  of  the 
ligaments,  bones,  mus- 
cles, and  articular  sur- 
faces, in  these  cases  of 
deformity,  are  easily 
comprehended.  The 
ligaments  are  of  course 
elongated  on  the  one 
side  of  the  dislocated 
joint,  and  shortened  on 
the  other  side ;  the  bones  are  altered  in  shape, 
occasionally,  where  pressure  is  produced  by  a 
neighbouring  bone,  and  sometimes  a  portion  of 
the  bone  is  twisted,  and  drawn  towards  the  unna- 
tural situation  of  that  one  with  which  it  articulates. 
The  muscles  are  elongated  or  shortened,  accord- 
ing as  their  points  of  attachment  are,  by  the 
deformity,  approximated  or  further  separated. 
rphe  articular  surfaces  undergo  great  alterations  : 
they  are  altered  in  shape  and  situation  by  the 
friction  of  the  parts  in  contact  producing  a  new 
synovial  surface  upon  its  new  situation,  while  a 
part,  or  the  whole  of  the  natural  joint  loses  its 
polished  surface,  and  becomes  adherent  to  the 
integuments,  while,  in  many  instances,  the 
altered  position  of  a  bone  brings  it  into  contact 
with  another,  with  which  naturally  it  had  no 
such  relation,  and  here  asjain  a  preternatural 
synovial  articulation  will  form,  in  accordance 
with  the  same  law  of  the  animal  economy,  by 
which  long-continued  pressure  will  produce  a 
synovial  bursa.  As  a  general  observation,  we 
may  state,  that  the  whole  limb  is  smaller, 
shorter,  and  feebler  than  the  sound  one,  and 
that  this  defect  increases  by  comparison  with 
the  sound  one,  as  the  child  grows.  M.  Cru- 
veilhier  has  also  found  that  individual  bones 
are  sometimes  singly  defective  in  their  growth, 
while  occasionally  only  the  portion  of  a  bone 
which  is  subjected  to  pressure  is  checked  in 
its  developement. 

The  deformities  described  above  are  gene- 
rally congenital,  but  they  are  also  occasionally 
produced  after  birth  by  accidental  causes; 
though  in  this  case  there  is  no  difference  in  the 
nature  of  the  distortion  or  in  the  anatomical 
condition  of  the  parts,  yet  they  are  less  fre- 
quently cured,  because  the  same  carelessness 
or  bad  management  which  has  too  often  occa- 
sioned the  accidental  form  of  the  disease  to 
creep  on  unheeded,  makes  the  parents  indiffe- 
rent as  to  the  cure,  while  the  deformity,  which 
has  not  mismanagement  for  its  cause,  is  imme- 


diately remarked  on  the  birth  of  the  child, 
excites  alarm  in  the  mind  of  the  parent,  and 
means  are  early  adopted  for  its  removal. 

This  part  of  our  subject  leads  us  to  notice  a 
deformity,  of  not  uncommon  occurrence,  but 
one  which  has  met  with  little  notice  from 
writers,  although  the  inconvenience  and  suffer- 
ing occasioned  by  it,  great  in  degree,  and,  as 
far  as  we  have  known,  permanent  in  duration, 
will  entitle  it  to  the  consideration  of  the  sur- 
geon. We  allude  to  that  state  of  the  foot 
wherein  the  arch  is  lost,  and  the  foot  rests  flat 
upon  the  ground.  It  is  met  with  generally, 
but  not  always,  in  those  children  of  the  lower 
classes  who  are  obliged,  in  their  early  youth, 
to  engage  in  laborious  occupations,  and  parti- 
cularly in  lifting  heavy  weights,  before  the 
powers  of  the  system  are  developed,  though 
we  have  known  it  to  occur  where  none  of  these 
causes  could  be  traced.  It  happens  generally, 
not  in  the  very  weak,  nor  in  the  firm  and  robust 
children,  but  in  those  who  have  the  promise  of 
developement  on  a  large  scale,  and  are  rapidly 
growing.  It  comes  on  insidiously,  and  is 
rarely  detected  until  too  far  gone  to  admit  of  a 
complete  cure.  The  marks  of  this  disease  are 
an  evident  alteration  in  the  shape  of  the  foot. 
The  dorsum  has  comparatively  lost  its  con- 
vexity, the  concavity  of  the  sole  is  entirely 
gone;  the  scaphoid  bone  projecting  below  un- 
naturally, and  the  inner  malleolus  falling  con- 
siderably inwards.  The  relative  position  of  all 
the  rest  of  the  foot  appears  natural.  The  pa- 
tient complains  of  pain  and  tightness  at  the 
upper  part  of  the  instep  passing  through  to  the 
sole  upon  attempting  to  elevate  the  heel  while 
standing.  Indeed,  in  aggravated  cases,  he 
cannot  lift  himself  at  all  upon  the  metatarsus, 
while  every  step  upon  an  uneven  surface  is 
accompanied  with  pain.  The  anatomical  cha- 
racters of  this  distressing  disease  consist,  as  far 
as  a  close  examination  of  the  living  parts  can 
detect,  for  we  have  had  no  opportunity  of  dis- 
secting them,  in  a  relaxation  of  that  ligament 
which  passes  between  the  os  calcis  and  navicu- 
lar bone,  and  on  which  the  fore  part  of  the 
astragalus  rests  and  moves.  It  will  be  quite 
evident,  from  an  examination  of  these  parts 
and  their  connexions,  that  this  supposition  is 
sufficient,  to  account  for  the  symptoms  that  are 
apparent,  and  the  idea  is  borne  out  by  the  fact 
of  the  point  of  the  scaphoid  being  further  sepa- 
rated than  natural  from  the  tubercle  of  the  os 
calcis,  which  may  be  readily  ascertained  by  the 
touch.  We  conceive  the  remote  cause  to  be  a 
certain  degree  of  inflammatory  action  in  the 
elastic  ligament  just  mentioned,  produced  by 
over-exertion,  before  the  part  had  acquired  its 
full  developement  and  strength.  The  morbid 
action  being  continued  by  the  continuance  of 
the  irritation,  the  elasticity  of  the  ligament  is 
impaired,  and  it  can  no  more  support  the 
weight  laid  upon  it ;  it  consequently  yields, 
and  is  stretched.  This  view  receives  some 
support  from  the  fact  of  the  tenderness  upon 
pressure  constantly  found  in  this  precise  spot, 
and  from  the  relief  afforded  to  the  more  dis- 
tressing symptoms  by  the  application  of  leeches 
and  counter-irritations. 


REGIONS  OF  THE  FOOT. 


351 


Another  deformity  of  the  foot  occasionally 
met  with  is  exactly  the  reverse  of  the  prece- 
ding ;  this  is  too  great  a  convexity  of  the  arch, 
by  which  the  foot  is  considerably  shortened, 
and  the  bearing,  anteriorly,  taken  from  the 
under  side  of  the  heads  of  the  metatarsal  bones, 
and  thrown  partly  upon  the  bases  of  the  first 
phalanges  and  upon  the  metatarso-phalangeal 
joint  itself.  From  the  tense  state  of  the  plantar 
fascia  we  must  suppose  that  this  structure  is 
shortened,  and  indeed  we  have  been  inclined 
to  consider  this  contraction  of  the  fascia  as  in 
some  degree  a  cause  of  the  deformity,  which 
Dupuytren  has  proved  to  be  the  fact  in  the 
parallel  case  of  contraction  of  the  fingers,  by 
shortening  of  the  palmar  fascia.  With  this 
view,  in  a  case  of  deformed  foot  which  lately 
came  under  our  notice,  we  divided  the  fascia 
plantaris,  and  certainly  with  considerable  tem- 
porary benefit.  We  have  not  been  able  to 
ascertain  why  the  relief  was  not  permanent,  as 
the  patient  lives  at  a  distance  ;  but  it  might  not 
improbably  arise  from  his  returning  to  work 
too  soon,  and  leaving  off  the  extension  of  the 
foot  which  had  been  adopted. 

(A.  T.  S.  Dodd.J 

FOOT,  REGIONS  OF  THE.— The  sur- 
gical anatomy  of  the  ankle  having  already  been 
given,  (see  Ankle,  Regions  of,)  it  remains 
for  us,  in  this  article,  to  describe  the  foot  pro- 
perly so  called,  that  is,  all  of  the  lower  extremity 
beyond  the  ankle.  This  part  comprises  much 
that  is  practically  interesting  and  important, 
both  in  its  pathology  and  surgery,  which  must 
be  evident  when  we  consider  the  vast  number 
of  ills  which  are  endured  in  the  feet.  The 
foot,  considered  as  an  entire  region,  is  na- 
turally and  obviously  subdivided  into  dorsal 
and  plantar  regions.  In  the  first  of  these 
we  observe,  1st,  the  dorsum,  or  instep,  ex- 
tending from  the  front  of  the  ankle  to  the 
heads  of  the  metatarsal  bones ;  2d,  the  toes 
themselves. 

I.  Region  of  the  dorsum. — We  see  the  instep 
falling,  with  a  gentle  curve,  forwards  from  the 
ankle,  and  forming  the  anterior  portion  of  that 
arch,  which  posteriorly  runs  through  the  ankle- 
joint  to  the  heel,  and  the  crown  of  which,  formed 
by  the  astragalus,  bears  the  weight  of  the  whole 
body.  This  most  remarkable  provision  for 
the  safety  and  efficiency  of  the  body  is  well 
deserving  of  particular  examination,  and  we 
shall  return  to  it  when  describing  the  plantar 
region.  The  curve  of  the  dorsum  just  men- 
tioned is  running  forwards  to  the  head  of  the 
metatarsal  bone  of  the  great  toe;  there  is 
another  arch,  a  lateral  one,  running  across  the 
foot,  of  which  the  inner  end  is  abrupt,  as  it 
bends  over  the  inner  side  of  the  ossa  naviculare 
and  cuneiforme  interna ;  the  outer  end  slopes 
off  more  gradually  to  the  os  cuboides  and 
metatarsal  bone  of  the  little  toe.  The  use 
of  this  arch  is  best  seen  also  in  the  sole, 
though  it  presents  itself  to  the  view  most 
strikingly  on  the  dorsum. 

The  principal  points  which  claim  our  atten- 
tion m  this  region  are:  — 

1.  The  integuments,  which  are  here  rather 


thinner  and  softer  than  in  other  parts  of  the 
limb,  but  varying  considerably  in  texture  ac- 
cording to  age,  sex,  and  habit :  they  are  also 
rather  thinner  on  the  outer  than  on  the  inner 
side.  2.  The  subcutaneous  cellular  tissue. 
This  is  rather  loose,  and  freer  from  fat  than 
in  other  parts  of  the  body,  permitting  free 
movement  of  the  superficial  parts  upon  those 
beneath.  This  laxity  of  the  cellular  tissue  is 
greatest  on  the  middle  of  the  instep ;  and 
accordingly  we  see  in  children  and  females, 
where  there  is  a  large  quantity  of  superficial  fat, 
and  in  effusions  of  water  or  other  fluids,  that 
the  skin  of  this  part  rises  most,  while  across 
the  ankle  and  the  roots  of  the  toes  there  is 
an  appearance  like  a  ligature  arising  from  the 
comparative  closeness  and  shortness  of  this 
cellular  web.  In  this  layer  also  we  find 
several  large  veins  and  some  branches  of 
nerves.  The  dorsal  veins  of  the  foot  run  in 
very  irregular  directions,  varying  in  size  in 
different  subjects,  but  mostly  collected  into 
two  plexuses,  which  form  in  front  of  the  inner 
and  outer  ankles,  the  saphena  major  and  minor 
veins.  The  course  of  these  veins,  though 
various,  is  generally  as  follows  : — The  saphena 
major  begins  to  shew  itself  pretty  conspicuously 
on  the  middle  and  inner  side  of  the  instep, 
and  running  to  the  inner  ankle  receives  in  its 
course  numerous  additions,  and  then  passes 
over  the  internal  malleolus.  The  saphena 
minor  is  seldom  found  in  a  notable  trunk 
on  the  foot ;  we  see  only  on  the  outer  side 
of  the  dorsum  several  small  branches  commu- 
nicating with  the  inner  plexus,  and  taking 
their  course  towards  the  outer  ankle;  there 
they  form  sometimes  one,  but  generally 
two  branches,  which  pass  sometimes  over, 
generally  behind  the  outer  malleolus.  It  is 
the  first  of  these  veins  that  is  principally  im- 
portant in  surgery,  as  it  occasionally,  and  we 
think  it  might  with  advantage  be  more  fre- 
quently, opened  for  the  detraction  of  blood. 
It  is  immediately  brought  into  view  by  a 
ligature  placed  above  the  ankle,  and  in  opening 
it  we  must  bear  in  mind  that,  from  its  super- 
ficial situation,  from  the  looseness  of  the  en- 
veloping tissue,  and  from  the  greater  distance 
of  the  ligature  from  the  point  to  be  punctured, 
the  vein  is  much  more  liable  to  roll  and  to 
foil  our  attempts  than  the  vein  at  the  elbow : 
we  must,  therefore,  take  the  precaution  of 
putting  the  fore-finger  above,  and  the  thumb 
below  the  spot  where  the  lancet  is  to  enter, 
which  will  retain  with  facility  the  vein  in  its 
place. 

The  varicose  distention  to  which  the  trunks 
of  the  saphena  veins  in  the  leg  are  peculiarly 
liable,  is  often  found  extending  to  their  minute 
commencing  branches  on  the  dorsum  of  the 
foot ;  so  much  so  that  the  whole  of  this  region 
is  irregularly  distended,  and  covered  with  the 
knots  and  •ramifications  of  the  distended  veins. 
This  morbid  state  is  dependent  upon  the  same 
causes  as  the  varicose  affection  of  the  veins 
of  the  leg,  and  can  be  remedied  only  by  the 
same  means,  but  with  this  additional  disad- 
vantage, that  the  mechanical  means  adopted 
for  their  relief  by  pressure,  owing  to  the  more 


3.52 


REGIONS  OF  THE  FOOT. 


conical  form  of  the  foot,  can  with  greater 
difficulty  be  retained. 

Besides  the  veins,  we  find  imbedded  in  this 
same  layer  of  cellular  tissue  a  number  of 
nervous  filaments,  which  should  be  remem- 
bered as  occasionally  interfering  with  operations 
on  this  part.  The  last  portion  of  the  saphenus 
or  long  cutaneous  nerve  runs  so  near  to  the 
saphena  major  vein  that  some  of  its  twigs 
pass  in  front  of  and  some  behind  it,  and 
have  been  occasionally  punctured  in  opening 
this  vein;  but  this  should  form  no  stronger 
an  objection  to  this  operation  than  a  similar 
arrangement  of  the  nerves,  and  a  similar 
accident  in  bleeding,  which  occasionally  hap- 
pens, should  be  allowed  as  an  objection  to 
venesection  at  the  bend  of  the  arm. 

3.  The  next  layer  brought  into  view  by 
dissection  is  a  thin  expansion  of  fascia,  con- 
tinuous with  the  anterior  annular  ligament  of 
the  ankle,  and  formed  of  fibres  running  in 
various  directions,  principally  transverse  and 
spreading  over  the  whole  of  the  dorsal  region, 
but  principally  at  the  upper  part.  The  ob- 
servations which  have  been  made  on  this  same 
fascia  when  covering  the  ankle  may  be  applied 
also  to  the  part  just  described,  (see  Ankle- 
joint,  Region  of,)  with  this  exception,  that 
as  the  dorsal  fascia  is  much  thinner  and  more 
incomplete  than  that  over  the  ankle,  matter 
would  here  not  be  so  tightly  bound  down,  nor 
would  it  present  so  strong  an  obstacle  to  the 
pointing  of  it  outward. 

4.  On  removing  the  layer  of  aponeurosis 
a  muscular  and  tendinous  stratum  is  exposed, 
comprehending  the  entire  muscle  of  the  ex- 
tensor brevis  digitorum  and  the  tendons  of 
several  of  the  long  muscles  situated  on  the 
leg.  The  first  of  these  has  a  thick  fleshy 
belly,  and  occupies  the  outer  part  of  the 
dorsum  of  the  foot,  sending  its  tendons  down, 
like  so  many  rays,  to  the  bases  of  the  toes. 
The  tendons  are  spread  over  the  foot  in  the 
following  order : — on  the  inner  side  the  tibialis 
anticus  passing  to  be  inserted,  by  a  broad 
attachment,  into  the  internal  cuneiform  bone 
and  base  of  the  first  metatarsal  bone ;  next 
the  extensor  proprius  pollicis  runs  forwards 
and  inwards,  along  the  fibular  edge  of  the 
first  metatarsal  bone;  then  the  tendons  of  the 
extensor  longus  digitorum  run  diverging  to- 
wards the  bases  of  the  four  outer  toes,  crossing 
over  the  tendons  of  the  extensor  brevis;  and 
lastly,  the  tendon  of  the  peroneus  tertius, 
diverging  from  the  extensor  longus,  sends  its 
small  flat  tendon  to  the  base  of  the  fifth  me- 
tatarsal bone.  Each  of  these  tendons  runs 
in  its  own  synovial  sheath,  and  these  are, 
from  their  superficial  situation  and  from  their 
proximity  to  the  bones  over  which  they  pass, 
peculiarly  liable  to  be  affected  by  pressure, 
as  from  tight  boots.  The  consequence  of  this 
is  not  unfrequently  seen  in  a  small  round 
swelling,  situated  generally  over  the  tarsal 
bones,  and  upon  one  of  the  tendons  of  the 
extensor  digitorum  longus.  It  is  first  dis- 
covered generally  by  its  tenderness,  and  when 
this  is  relieved  by  taking  off  the  pressure 
which  was  its  first  cause,  the  swelling  itself 


still  remains,  soft  and  elastic  to  the  touch, 
and  having  all  the  characters  of  an  enlarged 
bursa,  and  which  has  received  the  name  of 
ganglion.  The  cure  may  generally  be  accom- 
plished easily  and  expeditiously  :  a  smart  blow 
with  some  hard  body,  as  the  back  of  a  book, 
while  the  swelling  is  rendered  tense  by  the 
forcible  extension  of  the  foot,  will  be  all  that 
is  necessary;  the  cyst  is  thus  burst,  and  its 
synovial  contents,  when  extravasated  among 
the  adjacent  cellular  tissue,  soon  become  ab- 
sorbed, while  the  empty  cyst  itself  shrinks 
and  contracts  to  its  natural  size.  Should, 
however,  this  plan  not  be  approved,  or,  which 
may  happen,  not  succeed,  the  introduction  of 
a  cataract  needle  in  an  oblique  direction  under 
the  skin,  and  the  puncture  of  the  cyst,  will 
evacuate  the  fluid  into  the  surrounding  cellular 
tissue,  and  thus  effect  a  cure.* 

A  tumour  is  sometimes  formed  upon  the 
instep,  which  is  also  the  result  of  pressure, 
and  which  bears  a  near  relation  to  a  corn. 
It  is  met  with  in  young  men  who  wear  tight 
boots,  and  the  usual  situation  of  it  is  over 
the  articulation  between  the  internal  cuneiform 
bone  and  the  metatarsal  bone  of  the  great  toe. 
The  tumour  is  under  the  skin,  hard  and  im- 
movable ;  so  that  it  seems  to  a  superficial 
observer  to  be  an  enlargement  of  the  bone 
itself.  The  skin  over  it  is  in  a  natural  state, 
except  in  cases  of  long  standing,  in  which 
the  cuticle  becomes  thickened.  This  swelling 
is  described  by  Sir  B.  Brodie  in  a  clinical 
lecture  in  the  Medical  Gazette,  vol.  xvii. 
He  is  uncertain  in  what  precise  situation  this 
tumour  exists,  whether  in  the  ligaments  of  the 
joint,  or  periosteum,  or  in  the  ultimate  fibres 
of  the  tendon  of  the  tibialis  anticus  muscle, 
not  having  had  an  opportunity  of  dissecting  it. 

In  this  view  also  are  exposed  the  course  and 
situation  of  the  dorsal  artery  of  the  foot.  This, 
which  is  merely  the  continuation  of  the  anterior 
tibial  artery,  commences  its  course  from  the 
anterior  annular  ligament  of  the  ankle,  a  little 
to  the  inner  side  of  the  middle  of  the  foot ; 
from  thence  it  runs  obliquely  towards  the 
first  interosseal  space  of  the  metatarsal  bones, 
at  the  commencement  of  which  it  dips  into 
the  sole  of  the  foot,  leaving  only  a  branch  to 
continue  its  course  to  the  great  toe.  In  the 
course  just  mentioned  this  artery  rests  upon 
the  bones  of  the  tarsus,  separated  from  them 
and  their  ligaments  only  by  a  small  quantity 
of  cellular  tissue.  It  is  accompanied  by  its 
vein  and  a  branch  of  a  nerve,  and  will  readily 
be  found  running  along  the  outer  or  fibular 
edge  of  the  tendon  of  the  extensor  proprius 
pollicis,  which  partly  overlaps  it.  Notwith- 
standing the  superficial  situation  of  this  artery, 
its  close  connexion  with  the  above-mentioned 
tendon  renders  it  peculiarly  ineligible  for  the 
application  of  a  ligature,  and  fortunately  it  is 
very  rarely  that  we  are  called  upon  to  perform 
an  operation  upon  it;  but  its  course  and 
situation  are  important  to  the  surgeon,  as  afford- 
ing a  valuable  diagnostic  mark,  negative  at 

*  See  a  paper  on  Ganglion  by  C.  A.  Key,  Esq. 
in  the  1st  vol.  of  Guy's  Hospital  Reports. 


REGIONS  OF  THE  FOOT. 


353 


least,  if  not  positive,  in  the  examination  of 
an  injury  to  some  of  the  larger  vessels,  as  the 
femoral  or  the  anterior  tibial.  For  though, 
owing  to  occasional  varieties  in  the  course  and 
distribution  of  the  dorsal  arteries  of  the  foot, 
the  absence  of  pulsation  in  the  situation  of 
the  arteria  dorsalis  pedis,  just  indicated,  would 
not  be  a  positive  proof  of  injury  to  the  larger 
vessels,  (though  even  this  might  be  received 
as  valuable  corroborative  evidence,)  yet  the 
clear  and  full  pulsation  of  this  vessel  would 
of  course  be  undoubted  evidence  that  the 
larger  arteries  were  safe  and  sound.  (See 
Tibial  Arteries.) 

II.  Region  of  the  toes. — In  the  natural  state 
the  toes  are  covered  by  a  skin,  soft  and  pliable, 
except  the  extreme  phalanx,  the  dorsal  surface 
of  which  is  defended  by  the  nail,  for  the  struc- 
ture and  arrangement  of  which  we  refer  to 
the  article  Tegumentary  system.  Under 
the  skin  and  subcutaneous  tissue  we  find  the 
tendon  of  the  long  extensor,  lying  close  upon 
the  bone  adhering  to  it  and  to  the  synovial 
membranes  of  the  joints,  by  short  but  free 
cellular  tissue,  sufficiently  loose  to  allow  of 
the  free  movements  of  the  subjacent  joints. 
We  observe  that  the  length  of  the  toes,  by 
the  construction  of  the  bones,  much  shorter 
and  smaller  than  the  fingers,  appears  shorter 
still  in  the  metatarsal  phalanx  by  the  greater 
depth  of  the  integumental  web  between  the 
toes.  The  operator  will  do  well  to  remember 
this  in  amputating  at  the  metatarso-phalangeal 
joint,  or  he  will  surely  be  foiled  in  his  attempt 
to  open  it,  particularly  as  this  joint,  lying 
deeper  and  being  composed  of  smaller  bones 
than  the  corresponding  joint  of  the  hand,  is 
much  less  readily  perceptible,  even  to  the 
touch.  Lastly,  these  organs,  the  toes,  more 
universally,  and  in  greater  degree  perhaps  than 
any  other  part  of  the  body,  pay  the  penalty 
of  hyper-refinement  and  civilization  in  the 
distortion  and  disfigurement  of  their  entire 
structure  from  pressure.  The  skin  suffers  most 
acutely ;  it  becomes  entirely  altered  in  struc- 
ture. The  soft  cuticle  which  covered  it  is, 
by  the  irritation  of  pressure,  increased  in  thick- 
ness by  successive  additional  layers.  This 
increase  is  greatest  just  at  the  point  where 
there  is  most  pressure,  namely,  at  the  upper 
and  lateral  parts  of  the  projecting  joints; 
nature  thus  providing  a  defence  for  the  tender 
cutis,  pressed  between  the  bone  and  the  shoe. 
The  cause  of  irritation  being  still  continued, 
the  defence  itself  is  converted  into  an  ad- 
ditional enemy;  the  accumulated  layers  of 
hardened  cuticle  form  a  hard  corn,  and  irritate 
and  inflame  the  subjacent  cutis.  Another 
effort  of  nature  is  made  to  relieve  the  su  Bering 
parts  ;  a  small  bursa  is  formed  under  the 
most  prominent  part  of  the  corn,  and  this 
again  is  made  an  additional  cause  of  suffering 
by  this  part  also  becoming  inflamed,  the  original 
source  of  evil  not  being  removed.  The  same 
process  taking  place  between  the  toes  by  the 
pressure  of  one  toe  against  the  other,  produces 
the  soft  corn  by  the  moisture  of  this  part  not 
allowing  the  thickened  cuticle  to  become  hard 
and  dry.    The  same  process  on  a  larger  scale 

vol.  ir. 


over  the  joints  of  the  great  toe  occasions  the 
bunion,*  the  bursal  cysts  of  which  form  a 
beautiful  illustration  of  the  powers  of  nature 
in  accommodating  herself  to  accidental  circum- 
stances. 

Nor  is  the  mischief  arising  from  this  oppo- 
sition to  nature  confined  to  the  results  now 
mentioned.  The  toes,  from  being  constantly 
kept  in  a  distorted  position,  acquire  perma- 
nently an  unnatural  form,  sometimes  being 
bent  laterally  under  or  over  each  other,  the 
ligaments  become  stretched,  the  articular  car- 
tilages absorbed,  the  ends  of  the  bones  altered 
in  form,  and  anchylosis  is  not  unfrequently 
the  result.  If  the  shoe  be  too  short,  a  per- 
manent contraction  of  the  joint  of  the  toe  is 
produced,  which  is  sometimes  so  distressing 
in  walking  as  to  be  a  serious  impediment  to 
this  exercise,  and  even  to  demand  amputation 
of  the  toe  as  the  only  means  of  deliverance. 
This,  when  it  does  occur,  is  almost  always 
found  in  the  second  toe,  because  it  projects 
beyond  the  others. 

Plantar  region. — The  plantar  region,  like 
the  dorsal,  may  be  divided  into  the  plantar 
region,  strictly  so  called,  and  the  region  of 
the  toes. 

I.  Proper  plantar  region. — The  skin  upon 
the  sole  of  the  foot  is  covered  by  a  cuticle 
remarkable  both  for  its  general  density  and  for 
the  great  difference  of  its  density  in  different 
parts.  In  the  hollow  of  the  sole  it  is  thinnest, 
next  along  the  outer  side,  and  thickest  of  all 
under  the  heel  and  heads  of  the  metatarsal 
bones.  This  great  thickness  of  the  cuticle, 
though  partly  arising  from  pressure,  is  yet 
partly  natural,  being  found  in  some  degree 
even  in  the  foetus,  and  is  one  of  those  marks 
of  Provident  Wisdom  of  which  every  part  of 
our  structure  furnishes  instances.  The  cutis 
itself  is  still  more  striking  for  the  strength  and 
density  of  its  structure,  which  we  observe 
particularly  in  dissecting  this  part.  The  scal- 
pel must  be  sharp  indeed  to  cut  through  it 
with  ease.  This,  in  fact,  with  its  horny 
cuticle  is  nature's  provision  against  the  injuries 
to  which  the  important  parts  of  the  sole  are 
exposed,  and  the  only  defence,  the  only  sandal 
worn  to  this  day  by  multitudes.  Its  structure, 
as  shewn  by  removing  carefully  the  cellular 
tissue  from  its  inner  surface,  is  composed  of  a 
number  of  whitish  glistening  fibres  crossing 
each  other  in  every  direction,  and  enclosing 
in  their  meshes  portions  of  that  granular  fat 
which  forms  the  layer  immediately  subjacent 
to  the  skin.  These  meshes  are  closer  and 
smaller  as  we  approach  the  outer  surface, 
where  the  cells  entirely  disappear.  When  the 
cuticle  is  separated  from  it,  the  cutis  exhibits 
a  vast  number  of  exhalent  pores,  the  source  of 
that  profuse  perspiration  which  is  given  off 
from  this  part  of  the  feet  under  exercise  ;  these 
are  pretty  equally  distributed  over  the  sole,  but 
the  great  thickness  of  the  epidermis  at  the 
heel  must  impede  the  transpiration  through  it 

*  See  an  excellent  paper  by  Mr.  Key  in  Guy's 
Hospital  Reports.  Vide  Clinical  Lecture  on  Corns 
and  Bunions,  by  Sir  B.  C.  Brodie,  Bart,  in  the 
Med.  Gozette,  vol.  xvii. 

2  A 


354 


REGIONS  OF  THE  FOOT. 


to  a  considerable  degree.  The  sensibility  of 
this  part  of  the  integuments  is  not  at  all  in 
relation  to  its  apparent  want  of  delicacy  in 
structure ;  no  part  of  the  body  possesses  a 
covering  more  acutely  sensitive.  The  effects 
of  pricking,  of  titillation,  of  cold  or  heat 
applied  to  the  sole  of  the  foot,  exemplify  this. 
Its  sympathies  also  are  as  remarkable  for  their 
liveliness  as  for  their  extent.  Not  even  the 
arm-pits  or  sides  of  the  ribs  are  at  all  equal  to 
it  in  this  respect.  The  bladder,  the  urethra, 
the  stomach  and  intestines,  in  fact  almost  all  the 
mucous  membranes,  together  with  the  whole 
voluntary  system  of  nerves,  and  through  them 
the  whole  system  of  voluntary  muscles,  may 
be  said  especially  to  sympathize  with  and  to 
be  influenced  by  this  one  part.  Of  this  no 
one  can  doubt  when  we  see  the  effects  of 
sudden  cold  applied  to  it  in  relaxing  spasm  of 
the  urethra  or  bowels,  in  checking  vomiting, 
or  in  rousing  the  whole  nervous  and  muscular 
system  during  fainting,  &c.  The  effect  also  of 
hot  applications  of  stimulants  and  irritants 
applied  to  this  part  familiarly  illustrate  its  ex- 
tensive sympathies.  The  most  sensitive  part 
of  the  sole  is  the  hollow,  that  part  where  the 
cuticle  is  least  dense. 

When  the  cutis  is  removed,  we  expose  a 
stratum  of  cellular  tissue  remarkable  for  its 
density  and  toughness,  and  for  the  granular 
fat  witli  which  its  cells  are  filled;  it  lies  imme- 
diately under  the  true  skin,  and  over  the 
plantar  fascia.  We  may  here  observe  that  a 
similar  integument,  and  the  same  kind  of  cel- 
lular web  under  it,  is  spread  over  the  heel, 
and,  from  the  peculiarity  of  its  texture,  is 
probably  more  likely  to  inflame  under  the 
effects  of  pressure  than  the  skin  of  other  parts 
of  the  body  ;  at  any  rate,  it  very  frequently 
does  inflame,  and  even  slough,  when  long 
subjected  to  pressure  ;  and  inattention  to  this 
point  is  often  the  source  of  great  misery  in 
the  treatment  of  fractures  and  dislocations  of 
the  lower  extremity.  The  heel  resting  upon 
some  hard  portion  of  the  apparatus  often  so 
torments  the  patient  as  to  be  a  serious  impedi- 
ment to  the  successful  treatment  of  the  case. 

The  fascia  plantaris  demands  our  particular 
attention.  It  is  a  strong  tendinous  structure 
forming  a  covering  to  the  muscles  and  impor- 
tant structures  of  the  sole.  It  is  very  thick 
and  dense  at  its  posterior  part,  and  becomes 
thinner,  though  still  of  the  same  consistence, 
at  the  anterior  part.  The  cellular  web  just 
mentioned  strongly  adheres  to  it  externally, 
while  the  muscles  which  it  covers  are  not  only 
adherent  to  its  inner  side,  but  many  of  their 
fibres  arise  directly  from  it.  It  not  only  forms 
a  layer  of  separation  between  these  muscles 
and  the  more  external  parts,  but  it  sends  pro- 
cesses of  a  similar  tendinous  structure  between 
the  principal  muscles,  which  also  afford  origin 
to  many  of  their  fibres.  It  divides  itself  into 
three  portions,  one  covering  each  of  the  three 
principal  groups  of  muscles  found  here.  These 
three  portions  are,  however,  united  behind 
where  they  arise  in  common  from  the  under 
projecting  part  of  the  os  calcis,  while  ante- 
riorly the  layer  becomes  quite  incomplete  from 


the  subdivision  into  five  slips,  each  of  these 
again  splitting  to  pass  to  be  fixed  into  each 
side  of  the  heads  of  the  metatarsal  bones.  The 
situation,  structure,  and  connexions  of  this 
fascia,  of  the  dense  stratum  of  cellular  tissue, 
and  of  the  peculiar  skin  covering  this,  are 
highly  important  to  the  surgeon.  The  know- 
ledge of  these  points  teaches  why  phlegmonous 
inflammation  must  be  difficult  of  treatment, 
and  often  dangerous  in  its  results,  whether  it 
occurs  immediately  under  the  skin  or  under 
the  fascia,  but  particularly  in  the  latter  situa- 
tion, the  dense  unyielding  structure  of  which 
prevents  the  swelling  from  pressing  outward, 
thus  greatly  aggravating  the  pain  and  irritation, 
and  when  matter  has  formed,  equally  prevents 
its  pointing  outwards,  and  calls  for  the  early 
application  of  the  lancet  to  give  it  free  vent, 
and  thus  prevent  its  spreading  along  the  foot. 
The  structure  of  the  parts  just  described  is,  as 
far  as  it  goes,  an  objection  to  the  partial  ampu- 
tation of  the  foot  recommended  by  Chopart, 
wherein  the  flap  is  formed  from  these  parts  in 
the  sole,  together  with  the  muscles  and  tendons 
found  there.  But  this  objection  is  by  no 
means  fatal  to  operations  upon  these  parts, 
which  have  often  been  successfully  performed, 
and  when  they  are  so,  often  give  a  limb  much 
more  useful  than  a  wooden  one. 

We  now  come  to  the  deep-seated  parts  of 
the  foot.  These  consist,  1 .  of  the  muscles 
and  tendons ;  2.  of  veins  and  arteries  ;  3.  of 
nerves ;  4.  of  absorbents.  The  muscles  and 
tendons  compose  three  principal  groups  des- 
tined to  accomplish  the  movements  of  the 
great  toe,  of  the  three  middle  toes,  and  of  the 
little  toe,  and  according  to  their  destination 
and  use,  so  is  their  situation  in  the  sole.  On 
the  inner  side  the  abductor,  the  adductor,  the 
flexor  brevis,  and  tendon  of  the  flexor  longus 
pollicis  form  a  pretty  considerable  mass,  and 
have  a  separate  slip  of  the  fascia  plantaris 
lying  under  them,  in  contact  with  the  most 
superficial  of  them,  viz.  the  abductor.  On  the 
outer  or  fibular  side  of  the  sole,  a  similar  mass 
of  muscles,  but  smaller,  lie  underneath  the 
metatarsal  bone  of  the  little  toe,  composed 
also  of  an  abductor  and  a  short  flexor,  while 
one  slip  both  from  the  long  and  short  common 
flexors  joins  them  anteriorly.  The  space  be- 
tween these  two  masses  of  muscles  is  occupied, 
most  superficially,  and  immediately  in  contact 
with  the  plantar  fascia,  by  the  flexor  brevis 
digitorum,  next  by  the  tendons  of  the  flexor 
longus  digitorum,  accompanied  by  their  acces- 
sories ;  posteriorly,  the  accessories  or  massa 
carnea  Jacobi  Sylvii ;  and  anteriorly,  the  lum- 
bricales,  while  deeper  still  than  all  there  are 
the  interossei  interni. 

Amidst  this  number  of  small  muscles,  the 
plantar  arteries  take  their  course  in  the  follow- 
ing manner.  The  posterior  tibial  artery,  as 
we  have  elsewhere  seen  (vide  Ankle-joint, 
Regions  of),  passing  down  behind  the  inner 
malleolus,  gets  into  the  hollow  of  the  os 
calcis,  lying  pretty  close  to  this  bone,  and 
covered  only  by  the  integuments,  cellular 
tissue,  and  fascia.  It  now  passes  between  the 
origins  of  the  adductor  pollicis,  and  in  doing 


REGIONS  OF  THE  FOOT. 


3.55 


so  divides  into  external  and  internal  plantar. 
The  first  of  these,  which  is  much  the  larger 
of  the  two,  runs  in  a  somewhat  semicircular 
course,  first  forwards  and  outwards  till  it  has 
reached  the  base  of  the  metatarsal  bone  of  the 
little  toe,  and  then  winds  round  across  the 
other  metatarsal  bones,  till  at  that  of  the  great 
toe  it  terminates  by  uniting  with  the  anterior 
tibial.    In  this  course  it  runs  first  between  the 
superficial  and  deep  muscles,  viz.  first  covered 
by  the  abductor  pollicis,   then  between  the 
flexor  brevis  digitorum  and  the  long  flexor 
tendons ;   it  then  becomes  more  superficial, 
lying  between  the  flexor  digitorum  brevis  and 
the  abductor  minimi  digiti;  then  in  crossing 
back  to  the  inner  side  of  the  foot,  it  runs  deep 
under  all  the  muscles  and  tendons,  except  the 
interossei.     Thus  this  artery  forms  an  arch, 
called  the  plantar  arch,  having  its  convexity 
forwards  and  outwards,  its  concavity  inwards 
and  backwards.    The  branches  which  it  sup- 
plies in  this  course  are,  first,  a  number  of  large 
muscular  branches  before  it  reaches  the  outer 
side  of  the  foot ;  then  from  the  convexity  of 
the  arch  itself,  the  digital  arteries,  one  to  each 
metatarsal  space,  which,  dividing  at  the  first 
joint  of  the  toes,  run  one  on  each  side  of  the 
toe  to  its  termination  ;  and  lastly,  those  from 
the  upper  and  inner  sides,  being  generally  very 
insignificant  muscular  branches  and  communi- 
cating branches,  these  last  going  upwards 
between  the  metatarsal  bones  to  anastomose 
with  the  metatarsal  branches  of  the  anterior 
tibial  artery.    It  is  right,  however,  to  state 
that  in  this,  as  in  every  other  part  of  the 
arterial  system,   great  variety  is  occasionally 
found.    The  internal  plantar  artery  is  a  com- 
paratively small  artery,  merely  going  to  supply 
the  muscles  and  integuments  of  the  great  toe, 
and  for  this  purpose  passes  forwards  along  the 
under  and  inner  side  of  the  tarsus,  covered  by 
the  abductor  pollicis  as  far  as  the  first  phalanx 
of  the  great  toe,  where  it  divides  into  several 
branches,  supplying  both  sides  of  the  great  toe, 
and  the  inner  side  of  the  second.    The  veins 
which  accompany  the  plantar  arteries  are,  like 
all  deep-seated  veins,  two  in  number,  one  on 
each  side  of  the  artery,  and  they  terminate  in 
the  hollow  of  the  os  calcis  by  forming  the 
posterior  tibial  veins.    The  plantar  arteries  are 
accompanied  also  in  their  course  by  corre- 
sponding nerves,  the  termination  of  the  poste- 
rior tibial  nerve,  which  divides  in  the  hollow 
of  the  os  calcis.    The  internal  plantar  nerve, 
contrary  to  the  order  of  the  arteries,  is  the 
larger  of  the  two  ;  it  runs  in  company  with  the 
inner  plantar  artery,  and  sends  branches  to  the 
three  inner  toes,  and  to  the  inner  side  of  the 
fourth,  while  the  external  plantar  nerve  running 
the  course  of  the  corresponding  artery  is  dis- 
tributed only  to  the  fifth  toe  and  outer  side  of 
the  fourth.     The  lymphatics  of  the  sole  of 
the  foot,  like  the  rest  of  this  system,  are  com- 
posed of  a  superficial  and  a  deep  set,  the 
former  collecting  from  all  parts  towards  the 
inner  ankle;  the  latter  accompanying  the  plan- 
tar arteries  and  veins,  and  passing  up  also  with 
them  behind  the  inner  ankle,  go  with  the  tibial 
veins  to  the  ham.    There  are  several  synovial 


burste  in  this  region  which  it  is  necessary  here 
to  mention.  They  are  surrounding  the  tendons 
as  they  pass  into  the  sole  along  the  hollow  of 
the  os  calcis,  viz.  the  flexor  longus  pollicis  and 
flexor  longus  digitorum.  Their  anatomical 
description  has  been  already  given  (see  Ankle, 
Region  of).  Another  synovial  sheath  is 
surrounding  the  tendon  of  the  peroneus  longus 
as  it  obliquely  crosses  the  sole  to  its  insertion. 
This  bursal  cavity  is  situated  close  upon  the 
bone,  and  under  the  principal  ligaments. 

II.  Plantar  region  of  the  toes. —  Of  the 
toes  we  observe  that  the  integuments  of  the 
under  part  are  always  soft  and  pliable,  com- 
pared with  the  rest  of  the  integument  of  the 
sole,  and  possessing  peculiarly  the  sense  of 
touch  ;  that  under  the  skin  at  the  extremity 
of  the  toes  there  is  a  soft  elastic  cushion  of 
cellular  tissue,  analogous  to  that  at  the  tip  of 
the  fingers,  and  in  this  and  in  the  cutis  the 
extremity  of  the  digital  arteries  and  nerves  is 
minutely  ramified.  The  digital  arteries  them- 
selves, with  their  accompanying  nerves  and 
veins  and  absorbents,  are  running  along  the 
edges  of  this  under  surface  of  the  toes. 
Lastly,  the  tendinous  thecae,  in  which  the 
flexor  tendons  are  lying,  are  situated  along 
the  under  surface  of  the  phalanges  of  the 
toes,  and  are  particularly  attached  to  the  sharp 
edges  of  these  bones  (see  Foot,  Joints 
of).  They  have  a  smooth  synovial  lining 
which  prevents  the  effects  of  friction  upon  the 
tendons,  and  facilitates  their  movements. 

From  the  description  which  has  now  been 
given  of  the  organization  of  the  plantar  region 
of  the  foot,  we  readily  perceive,   1st,  Why 
deep  wounds  of  this  part  are  both  followed  by 
considerable  haemorrhage,  and  why  this  is  at 
the  same  time  very  difficult  to  stop.  The 
arterial  branches  are  numerous  and  lie  deep. 
Before  we  can  get  at  them  either  to  press  upon 
or  to  tie  them,  we  must  do  so  through  a  thick 
integument,  a  dense  tendinous   fascia,  and 
deep-seated  layer  of  muscles.    If  we  dilate 
the  opening  in  all  these  parts  we  wound  many 
more  branches,  while  it  is  impossible  at  such  a 
depth,  and  through  such  part,  to  discover  the 
bleeding  vessel,  if  the  opening  is  small.  We 
are,  therefore,  compelled  in  such  a  case,  if 
pressure  will  not  stop  the  haemorrhage,  to  tie  the 
posterior  tibial  artery,  either  behind  the  ankle 
or  at  the  lo  wer  third  of  the  leg.    But  even  this 
is  sometimes  not  sufficient  to  stop  the  haemor- 
rhage, owing  to  the  free  anastomosis  of  the 
arteria  dorsalis  pedis  with  the  plantar  arteries; 
and  we  are  then  compelled  also  to  tie  the 
anterior  tibial.    2d,  We  see  why  inflammation 
and  suppuration  in  these  parts,  whose  parietes 
as  well  as  contents  are  in  great  measure  ten- 
dinous, are  threatening  both  in  their  present 
symptoms  and  in  their  consequences.  Not 
only  is  the  ready  detection  of  suppuration  pre- 
vented, but  the  efforts  of  nature  to  bring  it  to 
the  surface  are  resisted.    The  inflamed  parts 
are  bound  tight;  if  matter  has  formed,  it  is 
obliged  to  burrow  laterally,  in  contact  with 
nerves,  arteries,  tendons,  &c.    The  inflamma- 
tion spreading  to  the  synovial  sheaths  either 
impairs  or  destroys   the  movements  of  the 
2  a  2 


356 


REGIONS  OF  THE  FOOT. 


tendons  in  them,  or,  going  still  further,  com- 
municates the  inflammation  to  the  tendon, 
and  occasions  it  to  slough.  Moreover,  the 
tendinous  structure  which  envelopes  some  of 
these  bursal  cavities  is  the  cause  of  those 
violent  and  alarming  symptoms  of  constitu- 
tional irritation,  by  no  means  uncommon  when 
only  a  very  small  quantity  of  matter  has  formed 
within  them,  a  state  sometimes  almost  instan- 
taneously relieved  by  a  judicious  opening  made 
with  the  lancet,  and  giving  exit  to  even  so  small 
a  quantity  of  pus.  3d,  Why  severe  contusions 
or  lacerations  are  here  so  often  followed  by  bad 
consequences,  the  power  of  repair  in  tendinous 
structures,  which  so  largely  enter  into  the 
composition  of  the  parts  about  the  foot,  being 
small,  and  consequently  the  inflammation  fre- 
quently proving  the  destruction  either  of  the 
stiuclure  or  the  functions  of  the  parts  affected. 

The  study  of  the  nature  and  position  of  these 
joints  of  the  foot  is  of  great  interest  and  im- 
portance to  the  surgeon,  and  it  will  not  be  in- 
appropriate in  this  article  to  offer  some  obser- 
vations upon  some  of  the  operations  in  which 
they  are  concerned.  Modern  surgery,  whose 
greatest  triumphs  have  been  in  the  saving  of 
limbs,  not  in  removing  them,  in  discovering  the 
least  possible  quantity  of  loss  by  which  the 
disease  might  be  eradicated,  rather  than  the 
readiest  method  of  taking  off  the  entire  limb, 
has  taught  us  not  to  be  deterred  by  the  intrica- 
cies of  the  numerous  joints  of  the  foot,  but 
fearlessly  to  lead  the  knife  through  any  part  of 
them,  so  that  we  may  only  save  a  serviceable 
portion,  which  may  be  more  convenient  than  a 
wooden  substitute.  The  removal  of  the  toes  at 
their  joints  is  comparatively  easy,  though  it 
should  be  remembered,  in  amputating  at  the 
metatarso-phalangeal  joint,  that  this  articulation 
is  situated  much  deeper  than  the  corresponding 
one  of  the  hand,  owing  to  the  greater  length  of 
the  web  and  greater  thickness  of  the  member 
itself.  The  metatarsal  bones  may  be  removed 
separately  or  altogether  from  their  junction  with 
the  tarsus,  as  first  done  by  Hey  of  Leeds,  and 
described  in  his  Surgical  Observations.  The 
removal  of  a  single  bone  is,  except  it  be  either 
the  first  or  the  fifth,  more  difficult  and  even 
more  dangerous,  in  regard  to  the  liability  to 
after  inflammation,  than  the  removal  of  the 
whole  metatarsus.  In  performing  this  last 
operation,  the  guide  for  entering  the  whole  row 
of  joints  is  the  projecting  tubercle  of  the  fifth 
metatarsal  bone,  immediately  behind  which  the 
joint  may  be  opened,  and  on  coming  to  the 
projection  of  the  inner  cuneiform  bone,  (see 
Jig.  167,)  most  surgeons  recommend  the  cutting 


Fig.  1 67. 


off  its  projecting  part,  rather  than  to  finish  by 
opening  the  joint.    The  tarsal  bones  have  been 


extracted,  both  with  and  without  the  attached 
metatarsal  bones.  Of  the  former  kind  a  very 
remarkable  instance  is  given  by  Mr.  Key  in  the 
second  number  of  Guy's  Hospital  Reports,  in 
which  the  only  bones  of  the  tarsus  left  were  the 
os  calcis,  astragalus,  scaphoid,  and  internal 
cuneiform  bones  as  a  support  to  the  great  toe. 
(Seeyfgs.  167  and  168,  in  the  first  of  which  the 
dotted  line  represents  the  portion  of  the  bones 
of  the  foot  which  was  removed  in  Jig.  168.) 

Fig.  168. 


Should  disease  or  accident  have  destroyed 
all,  or  most  of  the  bones  in  the  front  row  of  the 
tarsus,  they  may  all  be  readily  removed  by 
amputation  at  the  astragalo-scaphoid  and  calca- 
neocuboid joints,  an  operation  generally  known 
as  that  of  Chopart,  who  first  practised  it.  How 
far,  however,  such  a  portion  of  the  foot  pre- 
served is  preferable  to  the  use  of  a  short  wooden 
leg  applied  to  the  end  of  the  limb,  amputated 
a  little  above  the  ankle,  (a  plan  which  we  have 
used  with  perfect  success,)  certainly  admits  of 
a  doubt.  At  any  rate  its  advantages  cannot  be 
put  in  competition  with  the  principle  so  admi- 
rably illustrated  by  Mr.  Key  in  the  before 
mentioned  case,  of  saving,  if  possible,  a  portion 
of  the  metatarsus  and  toes,  though  at  the  risk 
of  a  more  painful,  and  perhaps  more  dangerous 
operation. 

Upon  a  general  survey  of  the  structure  and 
form  of  the  foot,  we  are  struck  with  the  differ- 
ence between  this  organ  in  man  and  in  all  other 
animals.  The  most  striking  peculiarities  con- 
sist in  the  great  breadth  of  the  foot,  its  short- 
ness in  proportion  to  the  leg,  the  large  size  of 
the  bones  of  the  tarsus,  the  relative  shortness 
and  smallness  of  the  four  outer  toes,  and  the 
great  size  of  the  inner  one,  the  great  strength 
of  the  calcaneum,  and  lastly,  in  those  arches 
produced  by  the  arrangement  and  form  of  the 
tarsal  and  metatarsal  bones.  The  only  animal 
that  nearly  approaches  to  the  form  of  man, 
the  monkey,  yet  differs  from  him  in  all  these 
points.  Its  foot  is  narrower  and  longer  in 
proportion  to  the  leg,  its  tarsal  bones  are 
smaller,  its  four  outer  toes  are  long  like  the 
fingers,  while  the  first  is  small,  and  separated 
from  the  rest.  The  calcaneum  is  relatively 
small,  and  inclines  upwards  at  its  posterior 
projection,  while  the  peculiarities  already  spe- 
cified necessarily  occasion  that  the  arches  of 
the  foot  are  much  less  distinct  than  in  man. 
Indeed,  in  supporting  itself  erect,  the  monkey 
rests  very  much  on  the  outer  side  of  the  foot, 
probably  on  this  account.  In  all  other  animals 
these  differences  are  still  more  marked.  What 


MUSCLES  OF  THE  FOOT. 


357 


now  can  be  more  evident  or  more  beautiful 
than  the  design  manifested  in  this  simple 
arrangement  of  the  foot !  Man  is  physically 
as  well  as  morally  intended  to  carry  him- 
self erect.  The  breadth  of  his  base  was  ne- 
cessary for  his  continued  support;  the  strength 
of  it  is  called  for  on  account  of  the  great 
weight  which  erect  progression  throws  upon 
it.  Its  arches  were  essential  not  only  to  give 
lodgment  and  defence  to  the  vessels  and  nerves 
of  the  plantar  region,  but,  by  the  peculiarity 
of  their  construction,  to  admit  of  a  certain 
degree  of  elastic  yielding,  which  greatly  dimi- 
nishes the  shocks  from  violent  efforts  in  leaping, 
running,  &c.  The  shortness  of  the  toes,  aug- 
mented by  the  depth  of  the  webs,  shows  that  pre- 
hension forms  no  part  of  the  design  of  the  foot, 
while  the  size  of  the  first  toe,  and  its  connexion 
with  the  others,  points  it  out  as  the  principal 
instrument  of  progression,  to  which  the  rest 
are  auxiliary.  The  analogies  between  the  foot 
and  the  hand  are  striking;  they  have  the  same 
general  arrangement  of  bones  and  muscles, 
and  even  the  arteries  and  nerves,  the  joints 
and  ligaments,  are  in  many  respects  similar, 
but  in  the  particulars  just  mentioned  the  dif- 
ference is  strikingly  obvious  and  important, 
and  just  in  these  respects  it  is  that  the  feet  of 
the  Quadrumana  also  differ  from  those  of  man, 
showing  a  difference  in  their  intended  action, 
the  erect  position,  at  the  utmost  being  only 
occasional,  not  being  the  natural  habit,  but  the 
foot  being  prepared  and  adapted  for  grasping 
and  clinging,  for  which  the  human  foot  is 
quite  unfit. 

The  construction  of  the  arches  of  the  foot 
requires  a  few  words.  They  are  two  in  number, 
a  transverse  and  a  longitudinal  one.  The  latter 
of  these  is  principally  found  along  the  inner 
edge  of  the  foot,  and  as  we  pass  towards  the 
outer  side  the  longitudinal  arch  gradually 
shortens  and  becomes  more  flattened,  until  at 
the  outer  side  the  arch  is  entirely  lost,  the 
bones  of  the  tarsus  and  metatarsus  resting 
through  their  whole  length  upon  the  ground. 
This  is  to  a  certain  degree  necessary  from  the 
construction  of  the  toes,  these  being  weaker 
and  shorter,  as  well  as  their  metatarsal  bones, 
as  they  are  further  from  the  great  toe ;  as  their 
strength  therefore  diminishes,  the  corresponding 
part  of  the  arch  is  shortened  and  flattened,  and, 
consequently,  less  strain  is  thrown  upon  them, 
until,  at  the  line  of  the  little  toe,  the  arch  is 
obliterated,  and  what  weight  is  resting  here 
comes  at  once  upon  the  ground.  But  from 
this  construction  it  follows  that  the  longest  and 
the  highest  line  of  this  arch  falls  upon  the 
strongest  metatarsal  bone  and  longest  toe,  and 
that  whatever  yielding  there  is  occurring  in  the 
entire  longitudinal  arch  is  greatest  in  this  part 
of  it.  This  is,  indeed,  proved  by  the  fact  that 
the  length  of  the  foot  in  a  sound  state  is  in- 
creased in  the  line  of  the  great  toe  to  the  extent 
of  several  lines,  by  resting  the  weight  of  the 
body  upon  the  foot,  whereas  it  is  not  at  all 
increased  in  the  line  of  the  little  toe.  When, 
therefore,  the  arch  yields  to  the  superincumbent 
pressure,  it  does  so  chiefly  along  the  inner  side, 
and  the  foot  is  thus,  to  a  certain  degree,  twisted, 


the  inner  malleolus  approached  nearer  to  the 
ground,  while  the  outer  is  very  little,  if  at  all, 
lowered.  This  explains  to  us  the  reason  of  the 
scaphoid  and  inner  cuneiform  bones  projecting 
as  they  do  in  the  flat  foot,  and  of  the  pain  ex- 
perienced on  the  inner  side  of  the  foot  in  the 
same  deformity  in  all  efforts  to  raise  the  heel  in 
walking.  It  may  also  in  some  degree  account 
for  the  fact  of  the  more  frequent  occurrence  of 
dislocation  of  the  tibia  at  the  ankle-joint  in- 
wards than  outwards,  the  arch  of  the  foot 
yielding  first  to  the  force  of  the  accident  on  the 
inner  side,  and  thus  tilting  the  whole  ankle- 
joint  inwards.  The  utility  in  walking  of  the 
form  and  relation  of  the  various  parts  of  the 
foot  now  mentioned  is  readily  seen  when  we 
unite  the  consideration  of  the  structure  of  this 
arch  with  the  combined  action  of  the  gastro- 
cnemii  upon  the  heel,  and  of  the  peroneus 
longus  upon  the  outer  side  of  the  foot.  The 
united  action  of  these  muscles  throws  and 
sustains  the  whole  weight  upon  the  strongest 
and  most  elastic  part. 

Whatever  has  been  said  of  the  utility  of  the 
longitudinal  arch  applies  equally  to  the  trans- 
verse arch,  which  is  supplementary  and  auxiliary 
to  the  former  in  all  its  uses. 

(A.  T.  S.  Dodd.) 

FOOT,  MUSCLES  OF  THE. — In  speaking 
of  the  muscles  of  the  foot  we  necessarily  under- 
stand not  merely  those  muscles  which  are  si- 
tuated upon  the  foot,  but  those  muscles  pecu- 
liarly belonging  to  it,  which  are  concerned  in 
producing  its  motions  wherever  situated.  The 
muscles  of  the  foot,  in  this  sense,  are  partly 
situated  upon  the  leg  and  partly  upon  the  foot, 
and  should,  in  a  physiological  view,  be  consi- 
dered together,  that  we  may  the  better  under- 
stand their  separate  and  combined  functions. 
We  shall  therefore,  in  this,  as  in  other  ana- 
tomical articles,  first  give  the  descriptive 
anatomy  of  the  muscles  situated  upon  the  foot, 
and  then  examine  their  functions  in  connexion 
with  those  others  whose  action  is  upon  the 
joints  of  the  foot,  and  which  are  therefore 
strictly  muscles  of  the  foot,  but  which  are 
anatomically  described  elsewhere.  (See  Leg, 
Muscles  of  the.) 

The  proper  muscles  of  the  foot  are,  1.  those 
on  the  dorsum  ;  2.  those  on  the  sole. 

The  muscles  on  the  dorsum  pedis  are  the  ex- 
tensor brevis  digitorum  and  the  dorsal  interossei. 

1.  The  extensor  brevis  digitorum  (Fr.  pe- 
dieux ). — This  is  a  short  flat  muscle,  situated 
upon  the  outer  side  of  the  tarsus  and  meta- 
tarsus. It  arises  by  fleshy  and  tendinous 
fibres  from  the  upper  and  anterior  part  of  the 
os  calcis,  in  thp  hollow  between  that  bone  and 
the  astragalus  (creux  astrugalo-calcanien ) ,  also 
partly  from  the  os  cuboides.  It  immediately 
forms  a  broad  fleshy  belly,  the  fibres  of  which 
pass  forwards  and  inwards,  and  divide  into 
four  portions,  from  each  of  which  proceeds  a 
slender  tendon.  These  four  tendons,  of  which 
the  two  internal  are  the  strongest,  cross  under 
those  of  the  long  extensor  of  the  toes,  opposite 
the  heads  of  the  metatarsal  bones.  Of  these 
tendons  the  internal  is  inserted  into  the  base  of 


358 


MUSCLES  OF  THE  FOOT. 


the  first  phalanx  of  the  great  toe,  the  others 
are  united  to  the  outer  edge  of  the  long  ten- 
dons, with  which  they  form  the  aponeurosis 
which  covers  the  dorsum  of  each  toe.  The 
obliquity  of  this  short  muscle  counteracts  the 
obliquity  of  the  long  extensor,  and  it  serves  to 
extend  and  to  spread  the  toes,  and  to  pull 
them  away  from  the  great  toe. 

2.  Interossei  dorsales  vel  externi. — These  are 
four  in  number,  and  arise  by  double  heads, 
that  is,  they  arise  from  both  the  contiguous 
metatarsal  bones,  here  occupying  the  whole  of 
the  interosseal  space,  and  thus  concealing  the 
internal  interossei,  which  are  seen  only  in  the 
sole.  Their  flat  tendon  unites  with  that  of  the 
long  and  short  extensors,  and  is  inserted  into 
the  side  of  the  bases  of  the  first  phalanges  of 
the  toes  in  such  a  manner  that,  with  internal 
interossei,  every  toe  has  one  of  these  little 
muscles  on  each  side  of  it,  except  the  first  toe, 
which  has  two  distinct  muscles  of  its  own  for 
the  same  action,  and  the  little  toe,  which  is 
provided  with  a  separate  abductor.  Their  use 
is  to  separate  the  toes,  and  perhaps  to  assist  in 
extending  them. 

In  the  sole  of  the  foot  the  inner  side  is 
occupied  by  the  muscles  of  the  great  toe,  con- 
stituting what  some  French  writers  call  the 
thenar  eminence.  These  muscles  are  as  fol- 
lows:— 

1.  Abductor  pollicis  pedis. — This  commences, 
by  a  tendinous  and  fleshy  origin,  from  the  tu- 
bercle on  the  under  and  fore  part  of  the  os 
calcis,  from  the  ligament  extending  between 
the  os  calcis  and  os  naviculare,  and  from  the 
fascia  plantaris.  Its  tendon  unites  with  the 
flexor  brevis  pollicis,  and  is  inserted  into  the 
internal  sesamoid  bone,  and  inner  side  of  the 
base  of  the  first  phalanx  of  the  great  toe.  It 
draws  the  great  toe  from  the  others. 

2.  Flexor  brevis  pollicis. — Lies  between  the 
abductor  and  adductor,  in  contact  with  the  me- 
tatarsal bone.  It  arises,  by  two  portions,  from 
the  under  and  fore  part  of  the  os  calcis,  and 
from  the  external  cuneiform  bone.  It  is  united, 
on  each  side,  to  the  abductor  and  the  adductor, 
and  is  inserled  with  these,  by  a  union  of  ten- 
dons, into  the  two  sesamoid  bones  and  base  of 
the  first  phalanx  of  the  great  toe,  having  the 
tendon  of  the  long  flexor  passing  between  the 
two  insertions. 

3.  Adductor  pollicis. — This  muscle,  which  is  si- 
tuated the  most  externally,  or  fibulad,  of  the  mus- 
cles of  the  great  toe,  commences  by  a  tendinous 
origin,  from  the  calcaneo-cuboid  ligament,  and 
from  one  or  two  of  the  metatarsal  bones.  It  is 
double  at  first,  and  then  uniting,  sends  a  tendon 
to  be  fixed  into  the  external  sesamoid  bone  and 
outer  or  fibular  side  of  the  base  of  the  first  pha- 
lanx of  the  great  toe,  in  close  connexion  with 
the  flexor  brevis.  It  draws  the  toe  towards  the 
others.  The  muscles  of  the  little  toe  are  situ- 
ated on  the  outer  edge  of  the  foot,  and  form,  in 
that  situation,  a  corresponding  eminence,  which 
has  been  called  the  hypothenar  eminence. 

1.  Abductor  minimi  digiti.- — This  arises  from 
the  outer,  under,  and  fore  part  of  the  os  calcis, 
and  from  the  fascia  plantaris.  It  forms  a  long 
slender  belly,  and  is  fixed  by  its  tendon  into 


the  base  of  the  first  phalanx  of  the  little  toe, 
and  head  of  its  metatarsal  bone.  It  flexes  and 
abducts  the  little  toe,  and,  by  its  attachment 
to  the  metatarsal  bone,  it  strengthens  the  arch 
of  the  foot,  which  indeed  may  be  said  of  almost 
all  the  muscles  of  the  foot. 

2.  Flexor  brevis  minimi  digiti  commences 
from  the  os  cuboides  and  base  of  the  metatarsal 
bone  of  the  little  toe,  and  lying  close  to  this 
bone,  it  is  inserted  into  the  base  of  the  first 
phalanx.  It  is  a  very  small  muscle,  and  its 
use  is  to  flex  the  toe. 

The  middle  of  the  plantar  region  is  occupied 
by  six  muscles  common  to  all  the  smaller  toes. 

1.  Flexor  brevis  digitorum,  called  also  per- 
forate.— This  muscle  arises,  fleshy,  from  the 
anterior  part  of  the  protuberance  of  the  os 
calcis,  also  from  the  inner  surface  of  the  plantar 
fascia,  both  from  its  central  thick  portion  and 
from  the  septa,  which  run  between  this  muscle 
and  those  of  the  great  and  little  toes.  Under 
the  metatarsus  it  sends  off  four  small  tendons, 
which,  entering  the  sheath  on  the  under  side 
of  the  four  outer  toes,  are  inserted  into  their 
second  phalanx.  Before  these  tendons  arrive 
at  the  point  of  insertion  each  of  them  splits,  to 
allow  the  passage  of  the  tendon  of  the  long 
flexor,  in  a  manner  similar  to  what  takes  place 
in  the  hand,  and  they  thus  have  a  double  inser- 
tion into  the  toe.  The  action  of  this  muscle  is 
to  flex  the  second  joint  of  the  four  lesser  toes. 

2.  Flexor  digitorum  accessorius,  or  massa 
carnea  Jacobi  Sylvii. — This  is  a  short  muscle, 
somewhat  square  in  form,  covered  by  the  flexor 
brevis  digitorum.  It  arises,  fleshy,  from  the 
sinuosity  of  the  os  calcis,  and  tendinous  from 
the  outer  side  of  the  same  part;  it  is  attached 
anteriorly  to  the  tendon  of  the  flexor  longus 
digitorum,  just  before  it  divides.  Its  use  is,  evi- 
dently, to  assist  the  action  of  the  long  flexor. 

3.  Lumbricales.- — These  slender  round  mus- 
cles are  found  between  the  tendons  of  the 
long  flexor  of  the  toes ;  they  arise  from  these 
tendons  just  after  their  division,  and  fix  their 
own  tendon  into  the  inner  or  tibial  side  of  the 
first  phalanges  of  the  four  outer  toes ;  they  act 
by  bending  the  first  joint  of  these  toes. 

4.  Interossei  plantares  vel  interni. — These 
are  three  in  number,  smaller  than  the  external, 
and  having  their  origin  each  from  only  one  me- 
tatarsal bone.  Their  insertion  and  action  have 
been  mentioned  when  speaking  of  the  external 
interossei. 

5.  Transversalis  pedis. — This  little  muscle 
is  situated  across  the  heads  of  the  metatarsal 
bones,  passing  from  the  fibular  side  of  the  great 
toe  to  the  tibial  side  of  the  little  one,  and  at- 
tached to  them  all  as  it  passes  over  them.  It 
goes  under  the  tendons  of  the  long  flexors  and 
the  lumbricales,  or  rather  between  them  and 
the  bones.  Its  action  is  to  draw  the  metatarsal 
bones  together,  thus  to  consolidate,  as  it  were, 
and  strengthen  that  antero-posterior  arch, which, 
were  its  parallel  portions  allowed  to  spread  out 
unchecked,  would  be  materially  weakened,  and 
be  less  able  to  encounter  the  violent  movements 
to  which  the  foot  is  liable  in  leaping,  running, 
&c. 

We  shall  now  enumerate  the  muscles  which 


MUSCLES  OF  THE  FOOT. 


359 


are  employed  in  the  movements  of  the  foot 
and  its  several  portions,  and  classify  them  ac- 


cording to  the  joints  upon  which  they  act  and 
the  movements  they  produce. 


"1.  Flexion  accomplished 

by  " 


The  motions  of  the  ankle- 
joint  are  •< 


2>  Extension  performed 
.by  


rl.  Downwards     and  in 
wards  accomplished  by  ." 

The  motions  between  the 
first  and  second  row  ofW 

tarsal  bones*  are  .    .    .  U    s  ,   


by 


1.  Flexion  performed  by  4. 

5. 


2.  Extension  by 

The  motions  of  the  toes  are-< 

3.  Abduction  by 

4.  Adduction  by 


In  this  table  we  are  struck  with  the  propor- 
tion which  the  antagonist  muscles  bear  to  each 
other,  both  in  numbers  and  in  individual  as 
well  as  collective  power.  This  proportion  is  of 
course  regulated  by  the  demand  for  muscular 
force  in  the  ordinary  movements  of  the  joints. 
The  extension  of  the  ankle,  in  the  most  ordi- 
nary mode  of  its  performance,  implies  the  lift- 
ing of  the  whole  weight  of  the  body  by  the 
elevation  of  the  heel,  the  toes  resting  upon  the 
ground.  This,  owing  to  the  unequal  length 
of  the  two  levers,  requires  an  immense  power, 
while  the  shortness  of  the  moveable  lever  allows 
of  very  little  extent  of  motion.    The  gastro- 


*  It  is  remarkable  that  so  original  and  accurate 
an  observer  as  Dr.  Barclay  should  attribute  this 
motion  to  the  ankle-joint,  and  sliould  deny  any 
motion,  more  than  a  mere  yielding,  to  any  of  the 
tarsal  bones.  But  it  is  still  more  surprising  that 
he  should  make  the  same  observation  of  the  carpus, 
when  so  very  considerable  a  part  of  the  ordinary 
motion  at  the  wrist  is  obviously  between  the  two 
rows  of  carpal  bones.  See  Barclay  on  Muscular 
Motion,  pp.  404,  447. 


Tibialis  anticus. 
Peroneus  tertius. 
Extensor  longus  digitorum. 
Extensor  proprius  pcfflrcis. 
Gastrocnemius  externus. 
Gastrocnemius  internus. 
Plantaris. 

Flexor  longus  digitorum. 
Flexor  longus  pollicis. 
Tibialis  posticus. 
Peroneus  longus. 
Peroneus  brevis. 
Tibialis  posticus. 
Extensor  proprius  pollicis. 
Flexor  longus  digitorum. 
Flexor  longus  pollicis. 
Peroneus  Longus. 
Peroneus  brevis. 
Peroneus  tertius. 
Extensor  longus  digitorum. 
Flexor  longus  pollicis. 
Flexor  brevis  pollicis. 
Flexor  longus  digitorum. 
Flexor  brevis  digitorum. 
Flexor  accessorius  digitorum. 
Lumbricales. 

Flexor  brevis  minimi  digiti. 
Extensor  proprius  pollicis. 
Extensor  longus  digitorum. 
Extensor  brevis  digitorum. 
Abductor  pollicis. 
Abductor  minimi  digiti. 
f  Pri< 
I  Prk 

(_  Prior  tertii  digiti. 
.  Adductor  pollicis. 
.  Transversalis. 

{Prior  minimi  digiti. 
Posterior  indicis. 
Posterior  meda  digiti. 
.  Posterior  tertii  digiti. 


cnetnii  are  accordingly  thick  short  muscles, 
with  a  long  and  powerful  tendon.  These  are 
assisted  by  the  plantaris  and  five  other  muscles. 
Flexion,  on  the  contrary,  which  generally  im- 
plies merely  the  elevation  of  the  foot,  without 
any  other  force  to  overcome,  is  adequately 
provided  for  by  only  four  muscles,  and  these 
not  large,  indeed  one  of  them  very  small. 
The  assistance  rendered  by  the  five  auxiliary 
muscles,  which  pass  behind  the  malleoli, 
though  considerable  on  the  whole,  yet  is  small 
individually  in  proportion  to  their  size,  owing 
to  the  disadvantageous  situation  which  their 
tendons  occupy  at  so  very  short  a  distance  from 
the  centre  of  motion  ;  for  this  reason, — when 
the  tendo  Achillis  is  ruptured,  the  patient  is 
as  incapable  of  walking  as  if  all  the  extensor 
muscles  were  divided,  yet  when  the  body  is 
resting  the  antagonism  of  the  extensors  is  not 
entirely  lost.  The  foot  is  not  permanently  bent 
upwards,  and  the  simple  act  of  extension  can 
be  accomplished  without  great  difficulty.  One 
of  the  most  remarkable  of  all  the  extensor 
muscles,  both  as  to  its  course  and  its  function, 


rior  indicis. 
InterosseH  Prior  medii  digiti. 


360 


MUSCLES  OF  THE  FOOT. 


is  the  peroneous  externus.  (See  Leg,  Mus- 
cles of.)  The  tendon  of  this  muscle  passes 
behind  the  outer  malleolus,  then,  running 
downwards  and  forwards,  it  enters  a  groove 
formed  in  the  os  calcis,  close  behind  the  pro- 
minence of  the  base  of  the  fifth  metatarsal 
bone.  It  then  runs  across  the  sole  of  the  foot, 
in  contact  with  the  bones,  to  be  fixed  to  the 
inner  cuneiform  bone  and  metatarsal  bone  of 
the  great  toe.  The  course  and  situation  of  the 
tendon  well  deserve  particular  attention  in  the 
dissection  of  the  foot.  Without  some  study,  it 
is  impossible  fully  to  understand  its  office,  or 
how  essential  its  action  is  to  the  mechanism  of 
progression.  If  we  examine  the  general  form 
of  the  foot,  we  see  that  the  anterior  end  of  it  is 
not  square,  owing  to  the  comparative  length  of 
the  toes.  These  are  not  of  equal  length,  but 
are  each  shorter  than  the  other  as  we  proceed 
outwards,  the  outermost  of  all  being  the  short- 
est. This  part  of  the  foot  then  is  like  the  end  of 
an  oblong,  with  one  angle  greatly  rounded  off. 
When,  therefore,  the  weight  of  the  body  is,  by 
the  elevation  of  the  heel,  thrown  forwards  upon 
the  toes,  there  is  necessarily  a  tendency,  in  this 
shape  of  the  foot,  to  tilt  the  pressing  force  out- 
wards, whereas  if  all  the  toes  had  been  of  equal 
length,  the  elevation  of  the  heel  would  simply 
have  thrown  the  weight  directly  forwards,  the 
support  being  equal  on  both  sides  of  the  foot. 
This  tendency  outwards,  occasioned  by  the 
difference  in  length  of  the  toes,  is  still  further 
increased  by  the  difference  in  strength,  the 
largest,  the  most  unyielding  support,  being  on 
the  inner  side  of  the  foot,  the  smallest  and  the 
most  yielding  being  on  the  outer.  This  then 
being  the  construction  of  the  basis  of  support, 
some  means  of  counteracting  this  tendency  was 
necessary  to  enable  us  to  carry  the  body  directly 
forwards,  even  in  the  simple  act  of  walking, 
and  still  more  in  the  more  violent  exertions. 
This  is  accomplished  by  the  peroneus  longus, 
whose  tendon,  like  a  girt,  passes  under  the 
outer  edge  of  the  sole,  and  thus,  lifting  this, 
and  in  some  degree  turning  the  sole  outwards, 
throws  the  weight  of  the  body  upon  the  great 
toe.  This  action  of  the  muscle  is  particularly 
exemplified  in  the  movements  of  skaiting. 

The  movements  of  the  bones  of  the  tarsus 
are  so  distinct  and  constant  that  we  have  clas- 
sified the  muscles  which  act  upon  them  sepa- 
rately from  those  of  the  ankle.  (See  Foot, 
Joints  of.) 

The  muscles  of  the  great  toe  are  remarkable, 
as  might  be  expected,  for  their  size  and  strength. 
The  long  flexor  is  considerably  larger  than  that 
common  to  the  other  toes,  and  gives  to  this  a 
slip  of  its  tendon,  so  that  the  flexor  longus  pol- 
licis  does  in  fact  assist  in  flexing  all  the  toes. 

The  general  arrangement  of  all  the  muscles 
and  tendons  in  the  sole  is  very  curious,  and 
has  a  further  object  than  the  mere  flexion  of  the 
toes.  The  great  toe  is,  as  we  see,  well  provided, 
and  it  needs  this,  since  it  bears  the  greatest 
share  of  the  burden  of  the  body  in  walking, 
&c.  The  muscular  provision  for  the  other  toes 
is  as  considerable,  and  indeed  more  so,  in  pro- 
portion to  the  size  of  the  toes.  There  is,  1st, 
the  flexor  brevis  digitorum ;  2d,  the  flexor  longus 


Fig.  169. 


1  Flexor  accessorius. 

2  Flexor  pollicis  longus. 

3  Flexor  digitorum  longus. 

4  Slip  from  the  flexor  pollicis  longus  to  the  flexor 

digitorum  longus. 

5  Lumbricales. 

6  Tendon  of  long  flexor. 

digitorum  ;  3d,  this  tendon  receives  an  aux- 
iliary tendon  from  the  long  flexor  of  the  great 
toe;  4th,themassacarnea;  5th,  the  lumbricales. 
There  can  be  little  doubt  that  the  use  of  all 
these  muscles  is  to  give  a  powerful  support  to 
the  antero-posterior  arch  of  the  foot,  to  which 
purpose  the  mere  ligaments  would  be  little 
equal.  But  we  must  admire  not  only  the 
number  and  force  but  the  arrangement  of  these 
muscles,  which  are  so  placed  as  to  act,  almost 
all  of  them,  from  the  same  centre,  and  there- 
fore with  greater  advantage  for  the  object  of 
strengthening  the  arch.  Thus  the  flexor  brevis 
digitorum  lies  pretty  nearly  central  in  this  region, 
while  immediately  under  it  the  flexor  longus 
digitorum,  running  from  within  outwards,  is 
crossed  in  the  opposite  oblique  direction  by  the 
flexor  longus  pollicis,  and  these  again  are  still 
further  checked  outwards  by  the  flexor  accesso- 
rius, so  that  the  centre  of  action  of  all  these  mus- 
cles and  of  the  lumbricales  also,  which  arise  from 
the  long  flexor  tendon,  is  in  the  same  line  as  the 
flexor  brevis,  which  lies  over  them,  and  as  a 
support  to  the  great  arch  of  the  foot  this  arrange- 
ment of  the  muscular  chords  must  have  a  pecu- 
liarly advantageous  effect. 

(A.  T.  S.  Dodd.) 
For  the  Bibliography,  see  Anatomy  (Intro- 
duction). 


FORE-ARM. 


361 


FORE-ARM,  (Surgical  anatomy),  (Anti- 
brachium ;  Fr.  Avant-brus;  Germ,  der  V order- 
arm  )■  This  term  is  applied  to  that  portion 
of  the  upper  extremity  which  is  situated  be- 
tween the  elbow  and  wrist-joint. 

In  the  well-formed  male  all  the  muscles  of 
this  region,  but  especially  the  supinators,  from 
the  fascia  which  covers  them  being  extremely 
thin,  when  thrown  into  action  stand  out  in 
strong  relief,  giving  an  appearance  of  great 
power  concentrated  within  a  small  space.  In 
the  female,  on  the  contrary,  the  fore-arm,  from 
the  great  preponderance  of  adipose  tissue, 
presents  a  swelling  outline  and  rounded  form, 
not  the  less  beautiful,  perhaps,  from  indicating 
deficiency  of  muscular  energy,  and  conveying 
the  idea  of  softness  and  dependence. 

The  usual  and  least  constrained  position  of 
the  fore-arm  is  with  the  hand  between  prona- 
tion and  supination,  that  is,  with  the  palm 
of  the  hand  inwards  and  the  dorsum  outwards; 
but  for  the  purpose  of  anatomical  description 
the  palm  of  the  hand  is  supposed  to  face  for- 
wards and  the  dorsum  backwards,  the  fore-arm 
being  extended.  In  this  position  the  fore- 
arm obviously  differs  from  the  arm  in  being 
wider  from  side  to  side  than  from  before  back- 
wards. Superiorly  it  presents  in  front  a  very 
slightly  convex  surface,  but  inferiorly  there  is 
formed  by  the  flexor  tendon  a  distinct  central 
projection,  which  is  bounded  by  the  flexor  carpi 
radialis  on  the  radial  side,  and  by  the  flexor  carpi 
ulnaris  on  the  ulnar. 

The  posterior  surface  of  the  fore-arm  is  more 
irregularly  convex  than  the  anterior;  the  greatest 
convexity  is  nearer  the  ulnar  than  the  radial 
edge,  and  is  formed  by  the  olecranon  above 
and  the  shaft  of  the  ulna  below,  which  is 
covered  only  by  the  skin  superiorly.  A  con- 
siderable depression  may  be  observed,  bounded 
on  the  inner  side  by  the  olecranon,  and  on 
the  outer  by  the  supinators ;  in  this  depression 
the  outer  condyle  may  be  felt.  To  the  inner 
side  of  the  olecranon  there  is  a  corresponding 
but  much  smaller  depression,  in  which  the 
inner  condyle  is  situated.  For  about  three 
inches  above  the  wrist-joint  the  fore-arm  pos- 
teriorly is  slightly  concave  in  the  centre  in 
consequence  of  the  marked  projection  of  the 
ulna  and  radius  on  either  side.  In  the  motions 
of  pronation  and  supination  the  shape  of  the 
fore-arm  is  considerably  changed ;  but  as  no 
practical  advantage  can  attend  a  detailed  ac- 
count of  the  changes  undergone,  we  shall  not 
dwell  upon  them  here. 

The  parts  composing  the  fore-arm  are  as  fol- 
low :  the  radius  and  ulna,  the  muscles  of  the  hand 
and  fingers,  the  radial  and  ulnar  arteries  with 
their  branches,  the  venae  satellites  of  these 
arteries  and  the  subcutaneous  veins,  the  radial, 
ulnar,  median,  and  cutaneous  nerves,  the  ab- 
sorbent vessels,  a  quantity  of  cellular  and 
adipose  tissue,  various  aponeuroses,  and  the 
common  integuments. 

The  configuration,  relative  position,  and 
connection  of  the  bones  of  the  fore-arm  have 
been  described  in  the  article  Extremity. 
They  move  together  in  the  flexion  and  exten- 


sion of  the  fore-arm  on  the  os  humeri  at  the 
elbow-joint,  under  the  influence  of  the  biceps 
flexor  cubiti  and  brachialis  anticus,  and  the 
triceps  extensor  cubiti  and  anconeus. 

In  the  motions  of  supination  and  pronation 
the  radius  is  always  rolled  upon  the  ulna, 
the  latter  remaining  perfectly  fixed,  though 
this  fact  has  been  disputed  in  consequence  of 
the  thick  sacciform  ligament  of  the  wrist  and 
the  tendon  of  the  extensor  carpi  ulnaris  being 
felt  to  roll  under  the  finger  when  placed  on 
the  inferior  extremity  of  the  ulna  during  the 
motion  of  rotation  and  supination,  and  thus 
communicating  the  sensation  of  a  motion  in 
the  ulna  itself. 

The  skin  of  the  fore-arm  differs  considerably 
on  the  dorsal  and  anterior  aspects.  On  the 
former  it  is  coarse  and  comparatively  rough, 
containing  numerous  small  hairs  ;  on  the  latter 
it  is  smooth  and  more  delicate,  and  the  adipose 
tissue  being  more  abundant  on  the  anterior, 
the  whole  surface  is  more  even,  while  on  the 
posterior  the  extensor  muscles  of  the  hand 
and  fingers,  being  slightly  covered,  project 
considerably.  Neither  of  the  regions,  however, 
contain  so  much  fat  as  most  other  parts  of  the 
body. 

The  superficial  veins  which  are  subject  to 
the  greatest  variety,  are  usually  more  distinct 
and  numerous  on  the  dorsal  aspect,  particularly 
at  the  lower  part. 

The  subcutaneous  nerves,  which  are  very 
numerous,  are  derived  from  the  following 
sources  :  1st,  the  internal  cutaneous  nerve, 
which  is  one  of  the  divisions  of  the  axillary 
plexus;  2dly,  the  cutaneous  branch  of  the 
radial ;  3dly,  the  musculo-cutaneous. 

The  internal  cutaneous  nerve  divides  into 
two  branches  in  the  upper  arm,  in  which 
region  it  accompanies  the  basilic  vein.  These 
two  branches  penetrate  the  fascia  separately 
above  the  elbow-joint,  and  the  one,  the  an- 
terior branch,  descends  on  the  front  of  the 
fore-arm,  the  other,  the  posterior,  on  the  back 
of  it.  The  anterior  branch  usually  passes 
behind  the  basilic  vein,  sending  a  small  twig 
or  two  anterior  to  it.  Its  course  is  continued 
to  the  wrist-joint,  supplying  the  skin  on  the 
anterior  and  inner  side  throughout ;  the  pos- 
terior division  accompanies  the  basilic  vein, 
and  may  be  always  traced  to  the  back  part 
of  the  wrist. 

The  small  branches  of  this  nerve,  which 
cross  in  front  of  the  basilic  or  median  basilic 
vein,  are  occasionally  wounded  in  the  opera- 
tion of  venesection  ;  an  accident  which  gene- 
rally excites  considerable  inflammation,  with 
severe  constitutional  irritation,  symptoms  which 
are  sometimes  erroneously  attributed  to  the 
action  of  a  foul  lancet. 

The  skin  on  the  anterior  surface  of  the  outer 
half  of  the  fore-arm  is  supplied  with  nerves 
by  the  external  cutaneous  nerve,  a  division  of 
the  axillary  plexus :  it  is  a  deep-seated  mus- 
cular nerve  in  the  upper  arm  and  penetrates 
the  fascia,  becoming  subcutaneous  anterior 
and  a  little  below  the  elbow-joint.  In  this 
situation  it  is  posterior  to  the  median  cephalic 


362 


FORE-ARM. 


vein ;  its  branches  are  numerous  throughout 
its  course,  which  terminates  at  the  wrist-joint 
in  the  supply  of  branches  to  the  skin  on  the 
dorsum  and  ball  of  the  thumb,  which  inosculate 
with  the  cutaneous  of  the  radial. 

This  last-mentioned  branch,  the  cutaneous  of 
the  radial,  is  derived  from  its  trunk  on  the 
outer  side  of  the  middle  of  the  arm ;  imme- 
diately after  that  nerve  has  emerged  from 
between  the  triceps  extensor  and  the  bone,  a 
series  of  branches  is  distributed  to  the  skin 
of  the  arm.  The  remainder  of  the  nerve, 
which  is  a  descending  branch  of  some  size, 
passes  down  behind  the  elbow-joint,  and  be- 
coming subcutaneous  supplies  the  skin  of  the 
posterior  surface  of  the  outer  half  of  the  fore- 
arm, and  corresponds  to  the  musculo-cutaneous 
on  the  anterior.  Thus  it  will  be  seen  that 
the  skin  on  the  inner  side  of  the  fore-arm, 
both  anteriorly  and  posteriorly,  is  supplied  by 
the  internal  cutaneous,  while  that  on  the  outer 
side  is  supplied  in  front  by  the  musculo-cu- 
taneous, and  behind  by  the  radial  nerve. 

The  superficial  veins  of  the  fore-arm,  though 
subject  to  the  greatest  variety,  are  usually 
distinguished  by  the  names  of  the  cephalic, 
basilic,  and  median.  The  two  first  commence 
on  the  back  of  the  hand ;  the  cephalic  on  the 
external,  and  the  basilic  on  the  internal  side. 
They  freely  anastomose  at  the  lower  part  of 
the  fore-arm,  after  which  they  separate,  and 
reaching  the  anterior  surface  below  the  elbow, 
are  joined  by  the  median  vein,  as  described 
in  the  article  Elbow. 

The  superficial  absorbents  take  nearly  the 
same  course  as  the  veins,  though  they  are 
far  more  numerous,  and  on  the  whole  pursue 
a  straighter  direction.  The  course  of  these 
vessels  is  occasionally  demonstrated  in  the  living 
subject  by  active  inflammation  of  their  coats 
following  the  absorption  of  irritating  matter. 

Aponeurosis. — The  aponeurosis  of  the  fore- 
arm is  simply  a  continuation  of  the  same 
structure,  which  surrounds  and  supports  the 
muscles  of  the  upper  arm  ;  it  varies  very  much 
in  density  and  appearance  in  different  situa- 
tions ;  this  difference  arises  from  the  fact  that 
both  the  triceps  extensor  and  biceps  flexor 
cubiti  send  to  it  many  fibres,  which  not  merely 
give  additional  strength  to  its  texture,  but  also 
act  as  a  medium  through  which  these  muscles 
possess  the  power  of  making  tense  the  fascia. 
This  provision  for  tightening  and  supporting 
the  fascia  of  the  fore-arm  is  analogous  to  those 
arrangements  which  we  meet  with  in  the  thigh 
and  leg. 

The  fascia  of  the  fore-arm  is  strongest  at  the 
posterior  part  of  the  limb,  on  each  side  of  the 
olecranon.  The  fibres  derived  from  the  tendon 
of  the  triceps  on  the  external  side  pass  trans- 
versely outwards  to  be  inserted  into  the  outer 
condyle,  intermingling  with  the  radial  exten- 
sors at  their  origin,  at  the  same  time  firmly 
connected  to  the  olecranon  process,  posteriorand 
internal  edge  of  the  ulna,  thus  forming  a  dense 
and  firm  covering  to  the  anconeus,  between 
which  muscle  and  the  extensor  carpi  ulnaris  a 
process  of  fascia  is  met  with  which  forms  a 


dense  septum  between  the  two.  The  fibres 
from  the  internal  edge  of  the  triceps  at  the 
upper  part  also  pass  transversely,  reaching  the 
inner  condyle,  intermingle  with  the  origin  of 
the  flexor  muscles  ;  others  again,  descending  at 
the  back  part  of  the  arm,  form  an  aponeurosis 
over  the  flexor  carpi  ulnaris;  while  those  which 
pass  forwards  intermingle  with  the  aponeurotic 
fibres  of  the  biceps.  These  fibres  from  the 
biceps  are  uniformly  strong  and  distinct,  and 
give  a  great  firmness  and  density  to  the  fascia 
on  the  inner  side  of  the  arm  covering  the  flexor 
muscles,  which  is  not  met  with  on  the  outer 
side  of  the  arm  supporting  the  supinators. 
The  fascia  in  front  of  the  fore-arm  which  covers 
the  supinators  receives  its  last  fibrous  connexion 
from  the  tendon  of  the  deltoid.  The  fascia  of 
the  fore-arm  on  reaching  the  posterior  part  of 
the  wrist-joint  has  interwoven  with  its  texture 
many  beautifully  distinct  fibres,  taking  a 
slightly  oblique  course  from  without  to  within, 
and  from  above  to  below  ;  these  fibres,  which 
are  firmly  attached  to  the  radius  on  the  outer 
side  and  the  ulna  on  the  inner,  become  insen- 
sibly lost  in  the  fascia  on  the  back  part  of  the 
hand,  which  resembles  in  its  homogeneous 
appearance  the  fascia  on  the  lower  part  of  the 
fore-arm ;  these  supplementary  fibres  to  the 
fascia,  though  presenting  a  distinct  edge  neither 
above  nor  below,  act  as  a  ligament  to  the  exten- 
sor tendons  in  their  passage  behind  the  wrist- 
joint,  which  has  been  called  by  some  anatomists 
the  posterior  annular  ligament ;  between  these 
tendons  and  the  ligament  there  is  a  large  and 
distinct  bursa,  not  unfrequently  the  seat  of 
inflammation.  The  fascia  on  the  lower  and 
fore  part  of  the  fore-arm,  consisting  principally 
of  transverse  fibres,  becomes  gradually  thinner, 
and  in  front  of  the  wrist-joint  is  inseparably  in- 
terwoven with  the  fibres  of  the  annular  ligament. 

The  aponeurosis  of  the  fore-arm  forms  many 
septa  between  the  muscles.  Commencing  with 
the  description  of  the  septa  in  the  back  part  of 
the  arm,  we  find  a  dense  and  strong  one  sepa- 
rating the  anconeus  from  the  extensor  carpi 
ulnaris,  and  from  which  the  latter  muscle  takes 
part  of  its  origin.  A  second  dips  between  the 
extensor  carpi  ulnaris  and  extensor  communis 
digitorum,  giving  origin  to  both.  A  third  is 
found  between  the  common  extensors  of  the  fin- 
gers and  radial  extensors.  The  radial  extensors 
and  supinators  are  not  thus  separated  from  each 
other.  A  fourth  process,  distinct  though  com- 
paratively thin,  separates  the  supinator  radii 
longus  from  the  brachialis  anticus,  the  tendon 
of  the  biceps,  pronator  radii  teres,  and  flexor 
carpi  radialis.  There  is  also  another  process 
which  unites  the  tendon  of  the  supinator  radii 
longus  on  the  outer  side  to  the  flexor  carpi 
ulnaris  on  the  inner  side,  and  forms  a  firm  and 
dense  covering  to  the  radial  artery.  The  pro- 
nator radii  teres  is  scarcely  separated  from  the 
flexor  carpi  radialis  by  a  distinct  septum, 
though  the  last-mentioned  muscle  is  completely 
separated  from  the  palmaris  longui  by  a  dipping 
in  of  the  fascia.  Between  the  flexor  communis 
digitorum  sublimis  and  flexor  carpi  ulnaris 
there  is  a  very  perfect  and  distinct  septum. 


FORE- ARM. 


363 


Of  the  different  morbid  growths  which  arise 
in  the  cellular  tissue  of  the  fore-arm,  those 
■which  are  superficial  and  those  which  are 
beneath  the  fascia  require  careful  distinction, 
the  removal  of  the  former  being  easily  effected, 
while  all  operations  on  the  latter  require  great 
consideration  and  care. 

The  superficial  tumour  projects  under  the 
skin,  creating  some  deformity ;  it  may  be 
moved  with  facility,  for  its  attachments  are 
loose ;  while,  on  the  other  hand,  the  deep- 
seated  or  sub-fascial  tumour  has  frequently  a  flat- 
tened surface,  and  often  appears,  on  superficial 
examination,  insignificant  and  of  small  extent, 
while  in  fact  its  mass  is  considerable,  bur- 
rowing deeply  between  the  muscles.  It  is  to 
be  distinguished  from  the  supra-fascial  tumour 
by  its  comparative  immobility,  by  the  various 
effects  produced  upon  it  by  the  fascia  when 
in  a  state  of  tension  or  relaxation,  by  the  pain 
produced  by  pressure  on  nerves,  or  impediment 
to  the  circulation  from  pressure  on  the  vessels. 
In  the  removal  of  the  sub-fascial  tumour  the 
operator  must  call  to  mind  the  direction  and 
relative  position  of  the  muscles  in  the  neigh- 
bourhood of  it,  as  the  roots  or  under  surface 
of  these  generally  follow  the  interspace  between 
the  muscles,  and  are  thus  guided  to  a  great  depth 
among  the  vessels  and  nerves  of  the  fore-arm. 

The  same  principles  apply  to  the  diagnosis 
and  treatment  of  superficial  and  deep-sealed 
abscesses.  The  superficial  abscess  is  less  cir- 
cumscribed ;  the  matter  is  diffused  without 
limit  through  the  subcutaneous  tissue  ;  from 
its  position  the  absorption  of  the  superincum- 
bent tissues  takes  place  rapidly,  the  skin  either 
giving  way  entirely  without  the  aid  of  the 
surgeon,  or  else  pointing  at  some  particular 
spot  indicates  where  the  abscess  lancet  may  be 
employed  with  advantage. 

The  sub-fascial  abscess,  on  the  contrary,  pro- 
ceeds slowly  in  many  cases,  and  even  insidiously, 
bound  down  by  the  unyielding  fascia  ;  it  tells 
us  of  its  presence,  in  the  first  instance,  rather 
by  the  constitutional  disturbance  which  it 
rouses  than  any  striking  indications  of  local 
mischief.  These  abscesses  are  occasionally  the 
consequence  of  inflammation  commencing  in 
the  theca  of  the  flexor  tendons,  and  the  bur- 
rowing of  the  matter  upwards  in  the  course  of 
the  tendons.  The  septa  of  the  fascia,  which 
have  been  described  passing  down  between  the 
muscles  to  the  bone,  limit  the  passage  of  the 
pus  in  different  directions. 

The  fascia  itself  is  not  much  subject  to 
disease,  though  it  seems  peculiarly  disposed  to 
slough  as  a  consequence  of  phlegmonous  ery- 
sipelas. 

Vessels. — The  main  arteries  of  the  fore-arm  are 
the  radial  and  ulnar,  into  which  the  brachial 
artery  divides  just  below  the  bend  of  the  elbow. 
The  brachial  artery  at  this  spot  has  on  its  outer 
side  the  tendon  of  the  biceps  ;  on  its  inner 
side,  one  of  the  venae  comites,  the  median 
nerve,  and  the  pronator  radii  teres  muscle. 
Behind  the  brachial  artery  is  the  brachialis 
anticus  muscle,  and  in  front  of  it  the  fascial 
insertion  of  the  biceps  muscle. 


The  radial  artery,  which  is  the  smaller  of 
the  two  divisions,  pursues  nearly  the  same 
direction  as  the  brachial,  and  in  the  lower  part 
of  the  upper  third  of  the  fore-arm  is  found 
exactly  midway  between  the  radial  and  ulnar 
surfaces,  overlapped  by  the  supinator  radii 
longus,  and  lying  upon  the  tendon  of  the 
pronator  radii  teres  muscle,  with  the  radial 
nerve  about  a  quarter  of  an  inch  to  its  outer 
side,  and  separated  by  fat  and  cellular  mem- 
brane. From  this  point  the  radial  artery 
descends  towards  the  wrist-joint,  and  at  the 
lower  part  of  the  upper  half  of  the  fore-arm 
quits  the  pronator  radii  teres,  and  passes  on  to 
the  anterior  surface  of  the  flexor  longus  pollicis, 
having  the  flexor  carpi  radialis  to  its  inner  side. 
A  little  lower  down,  that  is,  at  the  upper  part 
of  the  lower  third,  the  vessel  emerges  from 
beneath  the  supinator  radii  longus  muscle,  and 
is  covered  only  by  the  fascia.  In  its  further 
course  to  the  wrist-joint  the  flexor  carpi  radialis 
maintains  its  position  on  the  inner  side,  to 
which  the  tendon  of  the  supinator  radii  longus 
corresponds  on  the  outer.  The  radial  nerve 
no  longer  accompanies  the  vessel,  for  it  has 
now  slid  under  the  supinator  radii  longus,  and 
reached  the  posterior  face  of  the  arm.  As  the 
radial  artery  just  above  the  wrist-joint  is 
covered  only  by  the  fascia,  and  lies  upon  the 
bone,  its  pulsations  are  easily  felt,  and  in  con- 
sequence of  its  convenient  situation  is  generally 
selected  by  the  medical  practitioner  to  ascertain 
the  general  state  of  the  circulation.  We  should, 
however,  always  bear  in  mind  the  great  variety 
both  in  size  and  distribution  to  which  this 
vessel  is  liable,  and  take  the  precaution  of  at 
least  examining  the  radial  artery  in  both 
arms. 

The  inner  edge  of  the  supinator  radii  muscle 
is  a  certain  guide  to  the  situation  of  this  artery 
should  the  surgeon  be  required  to  secure  it, 
and  this  should  always  be  effected  by  two 
ligatures,  as  its  free  anastomosis  below  will 
certainly  produce  secondary  hemorrhage  if  this 
precaution  is  neglected.  As  the  nerve  lies 
on  the  outer  side  of  the  artery,  the  needle 
must  be  passed  from  without  inwards. 

The  ulnar  artery  has  a  deep  course,  first 
passing  beneath  the  median  nerve,  which  se- 
parates it  from  the  pronator  radii  teres  muscle, 
next  beneath  the  flexor  digitorum  sublimis, 
the  two  last  muscles  separating  it  from  the 
flexor  carpi  radialis  and  palmaris  longus,  and 
upon  the  flexor  digitorum  profundus,  and  when 
it  reaches  the  tendon  of  this  muscle  midway 
between  the  wrist  and  elbow-joints,  it  comes 
into  contact  with  the  ulnar  nerve,  by  which 
it  is  separated  from  the  flexor  carpi  ulnaris 
muscle  on  its  inner  side.  In  its  further  descent 
to  the  wrist-joint  it  is  situated  between  the 
flexor  communis  digitorum  sublimis  and  flexor 
carpi  ulnaris.  Gradually  sliding  behind,  the 
tendon  of  the  latter  remains  covered  by  it 
for  about  two  inches  above  the  annular  liga- 
ment of  the  wrist,  in  front  of  which  it  passes 
into  the  palm  of  the  hand.  The  third  branch 
worthy  of  mention  in  this  division  of  the  fore- 
arm is  the  anterior  interosseal.    This  vessel 


364 


FORE-ARM. 


is  a  branch  of  the  ulnar  artery,  and  not  unfre- 
quently  is  of  large  size,  though  usually  of  a 
calibre  about  intermediate  to  the  two  last  men- 
tioned. It  arises  from  the  ulnar  artery  where 
that  vessel  is  covered  by  the  pronator  radii 
teres,  and  descending  towards  the  interosseal 
ligament  reaches  that  structure  a  little  below 
the  tendon  of  the  biceps.  It  is  accompanied 
by  a  branch  of  the  median  nerve  in  its  course 
downwards ;  lies  between  the  interosseous  liga- 
ments and  the  external  edge  of  the  flexor  com- 
munis digitorum  profundus ;  it  terminates  by 
dividing  into  two  branches,  of  which  one 
passes  backwards  through  the  interosseal  liga- 
ment, anastomosing  with  the  posterior  inter- 
osseal, and  the  other,  a  small  branch ,  descends 
over  the  wrist-joint  into  the  palm  of  the  hand, 
where  it  anastomoses  with  the  deep  palmar  arch. 

In  the  posterior  region  of  the  fore-arm  we 
meet  with  only  one  vessel  of  any  size  ;  this 
is  the  posterior  interosseal  artery,  a  branch 
from  the  anterior  interosseal,  which  passes 
through  the  interosseal  ligament  opposite  the 
tubercle  of  the  radius;  its  course  is  not  so 
straight  and  uniform  as  the  anterior,  its  distri- 
buent  branches  are  larger  and  more  numerous, 
and  it  may  be  said  to  ramble  down  between 
the  extensor  muscles  and  the  interosseal  liga- 
ment, though  it  does  not  lie  so  immediately  in 
contact  with  the  ligament  as  the  anterior  inter- 
osseal. It  terminates  by  anastomosis  with  the 
vessels  about  the  wrist-joint. 

Such  is  the  usual  distribution  of  these  ves- 
sels ;  they  are,  nevertheless,  subject  to  every 
kind  of  variety, and  theoperator  previously  to  the 
commencement  of  an  operation  ought  always 
carefully  to  examine  the  course  of  these  vessels 
in  order  to  detect  any  anormal  arrangement 
either  in  relation  to  their  size  or  distribution. 

The  arteries  of  the  fore-arm  are  more  ex- 
posed to  accidents  from  cutting  instruments 
than  most  other  vessels  in  the  body  ;  and  the 
usual  plan  of  securing  the  vessel  in  these  cases 
is  to  apply  two  ligatures  on  the  wounded 
trunk,  one  above  and  the  other  below  the  orifice, 
the  latter  being  required  in  consequence  of  the 
free  anastomosis  of  the  vessels  in  the  hand. 

But  the  fore-arm  is  occasionally  wounded  by 
sharp  penetrating  instruments,  which  passing 
deeply  into  the  fleshy  mass,  the  vessel  which 
has  been  wounded  is  not  immediately  indicated, 
and  the  surgeon  is  consequently  at  a  loss  to 
discover  which  of  the  three  main  trunks  requires 
the  application  of  a  ligature. 

An  examination  through  the  wound  would 
tend  to  aggravate  the  mischief,  and  besides, 
the  search  is  often  attended  with  difficulty,  and 
often  unsatisfactory. 

In  such  cases  it  will  be  found  far  more 
advantageous  to  arrest  the  hemorrhage  by  pres- 
sure on  the  brachial  artery,  at  the  same  time 
allaying  the  local  inflammation  by  due  attention 
to  the  position  of  the  arm,  and  the  usual 
antiphlogistic  remedies,  a  plan  which  I  have 
seen  adopted  with  great  success  by  Mr.  Tyrrell, 
at  St.  Thomas's  Hospital.* 

*  See  St.  Thomas's  Hospital  Reports,  edited  by 
John  F.  South,  No.  i.  p.  25. 


There  are  some  cases,  however,  which  im- 
peratively require  the  application  of  ligatures, 
as  for  instance,  when  either  of  these  vessels  is 
opened  by  sloughing  of  the  tissues  from  phleg- 
monous inflammation,  or  from  aneurism  in  the 
fore-arm  or  hand.  In  the  first  of  these  cases, 
patients  have  frequently  been  lost  from  the 
temporary  suspension  of  the  hemorrhage  by 
the  use  of  cold  applications  or  accidental 
circumstance,  and  its  occurring  again  suddenly 
during  the  absence  of  the  surgeon. 

In  the  performance  of  the  operation  of  tying 
the  radial  artery  the  supinator  radii  longus 
muscle  affords  an  unerring  guide  throughout 
the  fore-arm,  but  the  surgeon  must  remember 
that  the  inner  edge  of  this  muscle  is  not  on  the 
outer  side  of  the  fore-arm,  but  as  nearly  in  the 
centre  as  possible.  The  needle  must  be  passed 
from  without  inwards,  in  order  to  avoid  wound- 
ing the  nerve. 

The  ulnar  artery  cannot  be  secured  in  the 
upper  third  of  the  arm,  it  lies  so  completely 
covered  by  most  of  the  flexors  arising  from  the 
inner  condyle ;  as  soon  as  the  vessel  has  gained 
its  position  between  the  flexor  carpi  ulnaris 
and  the  flexor  digitorum  communis,  it  may  be 
easily  reached,  the  former  muscle  overlapping 
it,  and  therefore  forming  an  excellent  guide. 
The  needle  in  this  operation  must  be  passed 
from  within  outwards,  as  the  nerve  lies  to  the 
ulnar  side  of  the  artery. 

The  bones  of  the  fore-arm  are  not  unfre- 
quently  fractured,  either  singly  or  together,  but 
the  radius,  from  its  external  position  and  strong 
connection  with  the  bones  of  the  hand,  is  more 
frequently  fractured  than  the  ulna.  The  injury 
generally  takes  place  a  little  above  the  middle 
of  the  bone. 

When  both  bones  are  fractured,  the  accident 
is  frequently  occasioned  by  the  passage  of  a 
heavy  weight  over  the  limb,  the  violence  acting 
immediately  on  the  injured  portions.  Jn  child- 
hood these  bones  are  sometimes  bent  instead  of 
being  broken,  and  as  the  deformity  is  slight, 
though  the  effect  altogether  very  serious,  the 
nature  of  the  accident  is  not  very  readily  de- 
tected. 

"  When  these  bones  are  fractured  near  their 
inferior  extremities,"  says  M.  Boyer,*  "  the  in- 
flammatory swelling  might  render  the  diagnosis 
difficult,  and  cause  the  fracture  to  be  mistaken 
for  a  luxation  of  the  hand.  But  the  two  cases 
may  be  distinguished  by  simply  moving  the 
hand  ;  by  the  motion,  if  there  be  luxation  with- 
out fracture,  the  styloid  processes  of  the  radius 
and  ulna  will  not  change  their  situation ;  but 
if  a  fracture  do  exist,  these  processes  will  follow 
the  motion  of  the  hand." 

If  the  radius  be  fractured  a  little  below  the 
head  and  above  the  tubercle,  that  is,  through 
the  neck,  and  the  annular  ligament  remain  en- 
tire, the  deformity  is  so  slight  that  there  is  great 
difficulty  in  detecting  the  nature  of  the  injury, 
especially  if  there  be  much  swelling  and  effu- 

*  Lectures  of  Boyer  upon  Diseases  of  the  Bones, 
arranged  by  M.  Richerand,  translated  by  M.  Far- 
rell,  vol.  i.  p.  161. 


MUSCLES  OF  THE  FORE-ARM. 


365 


sion.  Unless  the  surgeon  can  distinctly  feel 
the  head  of  the  radius,  so  that  he  can  clearly 
ascertain  on  rotating  the  lower  portion  with  the 
hand,  that  the  upper  does  follow  but  remains 
perfectly  unmoved,  he  has  no  equivocal  guide 
as  to  the  real  nature  of  the  injury. 

If  the  ulna  is  fractured  separately  from  the 
radius,  which  seldom  occurs,  the  injury  gene- 
rally happens  to  the  lower  third  of  the  bone, 
which  is  much  smaller  and  more  exposed  than 
the  upper ;  the  accident  is  easily  detected  by 
running  the  finger  down  the  posterior  edge  of 
the  bone.  When  the  radius  is  fractured  near 
its  centre,  the  pronator  quadratus  muscle  ob- 
tains entire  power  over  the  bone,  and  drawing 
the  lower  portion  across  towards  the  ulna, 
causes  a  considerable  projection  in  the  anterior 
interosseous  space.  If  this  be  not  corrected  by 
the  use  of  a  pad,  as  recommended  a  little  fur- 
ther on,  the  two  bones  will  unite,  and  all  mo- 
tion of  pronation  and  supination  be  entirely 
lost. 

In  all  these  cases  of  fracture  of  the  bones  of 
the  fore-arm,  nearly  the  same  plan  of  treatment 
is  required,  namely,  1st,  two  pads,  increasing  in 
thickness  from  the  elbow  to  the  wrist,  and  not 
wider  in  any  place  than  the  arm  itself,  suffi- 
ciently soft  to  be  pushed  well  into  the  interos- 
seal  spaces,  applied  anteriorly  and  posteriorly ; 
a  long  linen  roller  enveloping  the  hand  and  the 
whole  of  the  fore-arm,  and  pressing  the  pads 
between  the  two  bones,  so  as  to  counteract  the 
action  of  the  two  pronator  muscles  which  have 
a  tendency  to  bring  them  together.  Splints  ex- 
tending from  the  elbow  to  the  hand. 

When  the  radius  alone  is  fractured,  it  is  ad- 
visable not  to  support  the  hand,  but  to  allow  it 
to  hang  down,  and  by  this  plan  the  hand  acting 
as  a  weight,  will  draw  the  lower  fractured  por- 
tion, which  has  a  tendency  to  overlap  the 
upper,  downwards,  and  thus  bring  them  into 
apposition. 

(Samuel  Solly.) 

FORE-ARM,  MUSCLES  OF  THE.— 
When  we  consider  how  varied  and  complex  are 
the  motions  of  the  arm  and  hand,  it  is  no  matter 
of  surprize  that  so  many  as  nineteen  muscles 
should  be  found  composing  the  fleshy  mass  of 
the  fore-arm. 

These  muscles  may  be  classified  in  reference 
to  their  action,  and  are  briefly  enumerated  as 
follows: — 

In  the  first  place  there  is  one  muscle  physio- 
logically belonging  to  the  upper  arm,  the  anco- 
neus ;  the  rest  are  connected  with  the  hand ; 
for  instance,  there  are  three  flexors  of  the  hand  ; 
flexor  carpi  radialis,  flexor  carpi  ulnaris,  pal- 
maris  longus.  Three  extensors  of  the  hand, 
extensor  carpi  radialis  longior,  extensor  carpi 
radialis  brevior,  extensor  carpi  ulnaris.  Three 
long  flexors  of  the  thumb  and  fingers  ;  flexor 
communis  digitorum  sublimis,  flexor  communis 
digitorum  -profundus,  flexor  longus  proprius 
pollicis.  Five  extensors  of  the  thumb  and 
fingers,  extensor  ossis  metacarpi  pollicis,  exten- 
sor primi  internodii,  extensor  secundi  internodii, 
extensor  communis  digitorum,  extensor  indicis. 


Two  supinators,  supinator  radii  longus,  supina- 
tor radii  brevis.  Two  pronators,  pronator  ra- 
dii teres,  pronator  quadratus. 

In  proceeding  to  describe  the  attachments 
and  relations  of  the  foregoing  muscles,  it  will 
be  found  convenient  to  examine  them  as  they 
are  met  with  in  the  following  regions  of  the 
fore-arm.  1.  The  anterior  region,  which  con- 
tains a  superficial  and  a  deep  set  of  muscles. 
2.  The  posterior  region,  which  likewise  has  its 
superficial  and  its  deep  layers  of  muscles. 
These  regions  again  may  be  conveniently  sub- 
divided into  radial  and  ulnar  sections,  between 
which  a  very  natural  line  of  demarcation  is 
observable  after  the  skin  and  adipose  tissue 
have  been  removed. 

Exactly  on  this  line,  and  one-thiid  from  the 
elbow  and  two-thirds  from  the  wrist-joint,  two 
long  muscles  will  be  found  in  contact,  the  supi- 
nator radii  longus  in  the  radial  section,  the 
flexor  carpi  radialis  in  the  ulnar.  Above  and 
below  this  point  these  muscles  diverge.  The 
flexor  carpi  radialis,  at  its  origin  from  the  inter- 
nal condyle,  is  distant,  from  the  boundary  line 
referred  to,  at  least  one-third  of  the  transverse 
diameter  of  the  arm,  and  the  space  thus  left, 
triangular  in  its  figure,  contains  a  large  portion 
of  the  pronator  radii  teres.  The  radial  edge  of 
the  pronator  radii  teres  is  in  contact  with  the 
supinator  radii  longus  to  the  extent  of  about 
an  inch  and  a  half;  this  muscle  descending  in 
like  manner  obliquely  from  its  origin  in  the 
ulnar  section  towards  the  radial  leaves  above  a 
similar  though  small  triangular  space,  in  which 
the  tendon  of  the  biceps  flexor  cubiti  is  lodged. 
Below  the  point  referred  to  above,  between  the 
elbow  and  wrist,  the  flexor  carpi  radialis  runs 
in  contact  with  and  on  the  ulnar  side  of  the 
boundary  line  till  within  an  inch  and  a  half  of 
the  wrist-joint,  where  it  gradually  slides  into 
the  radial  section,  so  that  at  the  annular  liga- 
ment the  tendon  of  the  flexor  carpi  radialis 
will  be  found  entirely  in  the  radial  region  with 
its  internal  edge  in  contact  with  the  boundary 
line. 

Thus  it  will  be  seen  that  a  line  drawn  from 
the  elbow  to  the  wrist  and  dividing  the  fore- 
arm into  two  portions,  of  which  the  internal 
or  ulnar  section  is  exactly  two-thirds,  while  the 
external  or  radial  section  is  only  one-third  of 
the  transverse  width,  not  merely  forms  an  arti- 
ficial division  into  radial  and  ulnar  sections, 
but  also  points  out  the  exact  situation  of  the 
tendon  of  the  biceps,  the  outer  edge  of  the 
pronator  radii  teres,  and  the  flexor  carpi  radi- 
alis, and  in  addition,  as  we  shall  presently  see, 
the  supinator  radii  longus.  The  fleshy  belly 
of  this  muscle  lies  exactly  parallel  with  this 
boundary  line  in  the  upper  half  of  the  arm. 

In  consequence  of  the  supinator  radii  longus 
becoming  tendinous  about  the  middle  of  the 
fore-arm,  and  the  tendon  being  narrower  in  its 
transverse  diameter  than  the  muscle,  a  space  is 
left  at  the  lower  part  of  the  arm  between  it  and 
the  flexor  carpi  radialis,  and  the  supinator  radii 
longus  is  no  longer  met  in  contact  with  the 
boundary  line.  In  this  space  is  lodged  the 
radial  artery,  lying  midway  between  these  two 


366 


MUSCLES  OF  THE  FORE-ARM. 


tendons,  separated  "from  the  flexor  longus  pol- 
licis  by  a  deep  layer  of  fascia,  which  is  united 
to  the  edge  of  the  supinator  radii  longus  on  the 
outer  side,  and  the  flexor  carpi  ulnaris  on  the 
inner  side 

Muscles  in  the  anterior  region  of  the 
fore-arm. — a.  Superficial  layer  of  muscles. — 
On  the  radial  side  we  observe  two,  supinator 
radii  longus  and  extensor  carpi  radialis  lon- 
gior. 

1.  Supinator  radii  longus,  (grand  supina- 
teur,  Cloq.,  brachio-radialis,  Soemm.,)  arises 
by  a  broad,  flat,  fleshy  origin  from  the  rough 
ridge,  on  the  outer  side  of  the  lower  extremity 
of  the  os  humeri,  which  gradually  terminates  in 
the  outer  condyle;  it  is  connected  at  the  apex  of 
its  origin  with  the  deltoid  :  it  arises  likewise 
from  the  intermuscular  ligaments  of  the  upper 
arm  ;  passing  over  the  elbow-joint,  its  surfaces, 
which  in  the  upper  arm  face  outwards  and  in- 
wards, are  converted  into  anterior  and  posterior 
in  the  fore-arm ;  opposite  the  tubercle  of  the 
radius  it  becomes  tendinous  on  its  under  sur- 
face, and  the  fleshy  fibres  on  its  anterior  face 
entirely  disappear  about  the  middle  of  the  fore- 
arm in  a  flat  tendon,  which,  narrowing  as  it 
descends,  is  inserted  into  the  external  edge  of 
the  base  of  the  radius. 

This  muscle  at  its  origin  has  to  the  inner 
side  of  it  the  brachialis  anticus  muscle  and  the 
radial  nerve  and  superior  profunda  artery;  to 
its  outer  side  and  posteriorly  the  triceps  ex- 
tensor cubiti;  a  little  lower  down  and  just 
above  the  elbow-joint  it  has  the  extensor  carpi 
radialis  longior  to  its  outer  side,  which  maintains 
a  uniform  relation  to  it  in  its  whole  course ;  in 
passing  over  the  elbow-joint  the  tendon  of  the 
biceps  flexor  cubiti  separates  it  from  the  bra- 
chialis anticus;  below  the  tendon  of  the  biceps 
muscle,  we  meet  with,  first,  the  pronator  radii 
teres  in  apposition  with  its  internal  edge  ;  and, 
next,  the  flexor  carpi  radialis.  In  contact  with 
its  posterior  face  superiorly  is  the  supinator 
radii  brevis  ;  below  this  muscle  the  tendon  of 
the  pronator  radii  teres ;  and  still  lower  down 
the  flexor  longus  pollicis. 

The  supinator  radii  longus,  in  addition  to  its 
action  as  a  supinator  of  the  hand,  is  a  flexor 
of  the  fore-arm  upon  the  arm. 

2.  Extensor  carpi  radialis  longior,  ( radi- 
alis externus  longior,  Soemm.,  humero  sus-me- 
tacurpien,  Chauss.,  Dumas,)  arises  from  the 
lower  extremity  of  the  ridge  above  referred  to, 
and  from  the  outer  condyle.  Advancing  for- 
ward it  passes  over  the  front  of  the  elbow- 
joint,  and  soon  becoming  tendinous  on  its  an- 
terior surface  descends  on  the  anterior  part  of 
the  fore-arm,  partly  overlapped  by  the  tendon 
of  the  supinator  radii  longus — its  tendon  gra- 
dually seeks  the  posterior  part  of  the  arm,  and 
running  through  a  broad  shallow  depression 
appropriated  to  it  and  the  second  radial  exten- 
sor, finishes  its  course  by  being  inserted  into  the 
back  part  of  the  metacarpal  bone  supporting 
the  index  finger.  This  muscle,  as  its  name 
implies,  is  an  extensor  of  the  hand,  possessing 
also  a  slight  power  in  effecting  its  abduction. 

In  the  ulnar  section  of  the  anterior  super- 


ficial antibrachial  region  we  find  five  mus- 
cles. 

1.  Pronator  radii  teres  arises  tendinous, 
above  the  elbow-joint  from  the  intermuscular 
ligament  of  the  upper  arm,  from  the  front  part 
of  the  internal  condyle  of  the  os  humeri,  from 
the  process  of  fascia  separating  it  from  the  flexor 
carpi  radialis,  and  from  the  ulna  close  to  the 
insertion  of  the  brachialis  anticus.  This  muscle, 
though  tendinous  at  its  origin,  soon  becomes 
fleshy,  and  from  its  rounded  form,  which  causes 
a  distinct  projection  beneath  the  skin  at  the  front 
and  upper  part  of  the  fore-arm,  derives  its  name. 
Its  fleshy  fibres  terminate  in  a  tendon  as  it 
enters  the  radial  section,  which  gradually  be- 
comes wider  as  it  descends,  and  sliding  behind 
the  supinator  radii  longus  and  extensor  carpi 
radialis  and  in  front  of  the  radius,  is  inserted 
into  the  outer  and  back  part  of  that  bone.  The 
pronator  radii  teres  has  to  its  outer  side,  supe- 
riorly, the  tendon  of  the  biceps  muscle;  below  the 
tubercle  of  the  radius  it  has  the  internal  edge  of 
the  supinator  radii  longus  in  apposition  with 
it,  and  as  it  slides  in  a  spiral  direction  round 
the  radius,  and  behind  this  muscle,  it  has  the 
supinator  radii  brevis  superior  and  external  to 
it ;  to  its  inner  side  it  has  throughout  its  course 
the  flexor  carpi  radialis. 

In  the  ulnar  section  the  anterior  surface  of  this 
muscle  is  in  contact  with  the  fascia;  in  the 
radial  it  is  covered  by  the  supinator  radii 
longus,  the  two  radial  extensors,  and  crossed 
by  the  radial  artery  and  nerve.  The  posterior 
surface  of  this  muscle  is  in  contact  with  the 
anterior  ligament  of  the  elbow-joint,  the  bra- 
chialis anticus,  the  median  nerve,  ulnar  artery, 
the  flexor  communis  digitorum  sublimis  and 
radius.  This  muscle,  while  presenting  a  smooth 
and  tendinous  face  to  the  under  surface  of  the 
supinator  longus  and  radial  extensors,  conti- 
nues fleshy  on  its  under  surface  to  the  very 
point  of  its  connexion  with  the  radius,  the 
muscle  beneath,  whose  surface  is  in  contact 
with  its  fleshy  fibres,  being  clothed  in  a  similar 
manner  with  tendon;  this  admirable  contri- 
vance for  preventing  friction  is  by  no  means 
peculiar  to  this  situation,  though  its  utility  is 
frequently  overlooked. 

The  name  of  this  muscle  indicates  its  action 
as  a  pronator  of  the  hand,  and  when  that 
effect  has  been  produced,  if  its  contractile 
power  be  still  further  excited,  it  will  flex  the 
fore-arm  upon  the  upper.  In  case  of  fracture 
of  the  radius,  this  power  is  excited  injuriously 
in  bringing  the  radius  across  the  ulna,  and  thus 
obliterating  the  interosseal  space,  and  if  not 
corrected  by  the  surgeon,  causing  unnatural 
union  of  the  two  bones. 

2.  Flexor  carpi  radialis  (  M.  radialis  internus, 
Winslow,  Albinus,  Lieutaud,  Sabatier,  Soemm. ; 
grand  palmaire,  or  radial  anterieur,  Cloquet ;) 
arises  from  the  internal  condyle  of  the  humerus 
in  common  with  the  last-mentioned  muscle;  at 
the  point  where  these  two  muscles  are  con- 
nected with  the  humerus  there  exists  no  na- 
tural separation  between  them.  About  an  inch 
and  a  half  from  their  origin  a  separation  is 
effected  by  the  dipping  in  of  the  fascia  forming 


MUSCLES  OF  THE  FORE-ARM. 


367 


one  of  the  muscular  septa  previously  referred  to. 
At  the  lower  part  of  the  upper  third  of  the  fore- 
arm their  separation  is  complete.  The  flexor 
carpi  radialis  first  changes  its  muscular  fibres 
for  tendinous  on  its  anterior  face,  and  a  rounded 
tendon  is  the  result  at  the  upper  part  of  the 
lower  third  of  the  arm.  This  tendon  passes  in 
front  of  the  wrist-joint  and  through  a  groove  in 
the  os  trapezium,  is  ultimately  inserted  into  the 
base  of  the  metacarpal  bone  supporting  the 
fore-finger. 

This  muscle  has  on  its  outer  edge,  in  the 
superior  third  of  the  fore-arm,  the  pronator 
radii  teres,  in  the  two  inferior  thirds  the  supi- 
nator radii  longus ;  the  palmaris  longus  to  its 
inner  edge,  both  at  its  origin  and  throughout 
its  whole  course  in  the  fore-arm.  Anterior  to 
it  there  is  simply  the  fascia,  its  posterior  face 
is  in  contact  with  the  superficial  flexor  of  the 
fingers  above  and  the  long  flexor  of  the  thumb 
below.  The  tendon  of  this  muscle  projects 
distinctly  through  the  skin  at  the  lower  part  of 
the  arm. 

The  flexor  carpi  radialis,  besides  flexing  the 
whole  hand  on  the  fore-arm,  bends  the  second 
row  of  carpal  bones  upon  the  first.  It  will  also 
act  as  an  abductor  of  the  hand,  in  consequence 
of  its  being  fixed  on  the  outer  side  of  the  hand 
in  the  pulley-like  groove  of  the  trapezium 
through  which  it  passes.  It  slightly  assists  the 
pronator  muscles  in  their  influence  over  the  hand. 

3.  The  palmaris  longus,  Soemm.,  epitrochlo- 
palmaire,  Chauss.  The  origin  of  this  muscle, 
which  is  in  common  with  the  other  flexors,  is 
from  the  inner  condyle,  also  from  a  tendinous 
intermuscular  septum  which  separates  it  from 
the  flexor  carpi  radialis  on  the  outer  side  and 
the  flexor  communis  digitorum  on  the  inner. 
This  muscle,  the  smallest  of  those  situated  in 
the  fore-arm,  becomes  tendinous  midway  be- 
tween the  elbow  and  wrist-joint.  This  tendon, 
which  is  narrow  and  slender,  descends  to  the 
annular  ligament,  and  is  ultimately  connected 
with  the  palmar  fascia.  This  fascia  has  some- 
times been  considered  as  a  mere  expansion  of 
the  tendon  of  the  palmaris  longus,  but  as  the 
muscle  is  occasionally  wanting  and  the  fascia 
never,  we  regard  it  rather  as  another  instance 
of  that  useful  connexion  of  muscles  with  fascia; 
which  we  have  already  had  occasion  to  admire. 
This  muscle,  except  at  its  origin  where  it  has 
the  flexor  carpi  radialis  to  its  inner  side  and  the 
flexor  communis  to  the  outer,  maintains  a  posi- 
tion completely  superficial  to  the  other  muscles, 
its  posterior  face  lying  upon  the  flexor  communis 
sublimis. 

This  muscle  flexes  the  hand,  and  makes 
tense  the  palmar  fascia  and  annular  ligament, 
and  thus  takes  off  from  the  palmar  vessels  and 
nerves  and  the  tendons  of  the  digital  flexors  the 
pressure  to  which  they  are  exposed  when  the 
hand  grasps  a  solid  body  firmly;  as,  for  in- 
stance, when  the  whole  weight  of  the  body  is 
sustained,  as  in  the  case  of  the  sailor  climbing 
the  rigging  of  a  vessel,  by  the  power  of  the 
flexors  of  the  fingers  and  hand. 

4.  Flexor  communis  digitorum  sublimis  per- 
forutus.   ( Muse ul us  perforatus,  Soemm.,  epi- 


troehlo-phalanginien  commun,  Chauss.)  This 
muscle  also  arises  from  the  inner  condyle  in 
common  with  the  other  muscles,  and  from  a 
strong  tendinous  septum  separating  it  from  the 
flexor  carpi  ulnaris.  About  the  middle  of  the 
fore-arm  this  portion  of  the  muscle  is  joined  by 
muscular  fibres  which  arise  from  the  radius  im- 
mediately below  the  insertion  of  the  supinator 
radii  brevis,  and  on  the  inner  side  of  the  pro- 
nator radii  teres.  Between  these  two  origins 
of  the  flexor  communis  digitorum  is  placed  the 
median  nerve.  The  tendinous  fibres,  into  which 
the  muscle  is  gradually  transformed,  become 
first  apparent  on  the  anterior  surface,  and  next 
being  collected  ultimately  split  into  four  cords, 
which  passing  behind  the  annular  ligament  of 
the  wrist,  enter  the  palm  of  the  hand ;  oppo- 
site the  first  phalanx  of  the  four  fingers  these 
cords,  splitting  into  two  portions  and  allowing 
the  passage  of  the  deep  flexors,  terminate  by 
being  inserted  in  the  rough  edge  on  the  sides 
of  the  second  phalanges.  The  tendons  of  this 
muscle  as  well  as  the  deep  flexor  are  bound 
down  to  the  phalanges  by  smooth  tendinous 
sheaths  or  thecal  which  are  dense  and  firm  be- 
tween the  articulations,  but  insensibly  disap- 
pearing opposite  the  joint,  where  their  presence 
would  interfere  with  the  motion  of  the  parts; 
they  are  lined  by  synovial  membrane  to  prevent 
unnecessary  friction. 

Although  the  lateral  width  of  this  muscle  is 
considerable,  only  a  very  narrow  edge  is  in 
contact  with  the  fascia,  the  remainder  being 
covered  by  the  last-mentioned  muscles,  so  that 
some  anatomists  have  described  it  as  constitu- 
ting a  middle  layer. 

On  the  internal  edge  is  placed  the  flexor 
carpi  ulnaris,  which  maintains  the  same  relative 
position  to  it  throughout  the  fore-arm.  In 
contact  with  its  posterior  face  we  have  the 
flexor  digitorum  profundus,  the  flexor  longus 
pollicis,  and  the  ulnar  artery,  vein,  and  nerve. 

This  muscle  flexes  the  second  phalanx  on 
the  first,  and  the  first  on  the  metacarpus,  and 
the  whole  hand  on  the  fore-arm. 

5.  Flexor  carpi  ulnaris,  (musculus  ulnaris 
internus,  Soemm,  cubital  interne,  Portal,  cu- 
bito-carpien,  Chauss.)  This  muscle  arises  from 
the  internal  extremity  of  the  internal  condyle 
of  the  humerus  from  the  tendinous  intermuscu- 
lar septum,  between  it  and  the  flexor  carpi  digi- 
torum sublimis,  and  from  the  olecranon  process 
of  the  ulna;  between  these  two  heads  the  ulnar 
nerve  is  situated ;  its  origin  from  the  ulna  is 
not  limited  to  the  olecranon  process,  for  it  con- 
tinues its  connexion  with  that  bone  nearly  as 
low  down  as  the  origin  of  the  pronator  quad- 
ratus.  This  muscle,  which  arises  tendinous 
and  fleshy,  merges  into  tendinous  fibres  on  its 
anterior  surface  at  the  upper  part  of  the  lower 
third  of  the  fore-arm.  The  tendon  by  degrees 
becomes  more  rounded,  but  does  not  cease  to 
receive  fleshy  fibres  until  it  terminates  by  be- 
coming inserted  into  the  annular  ligament  and 
os  pisiforme. 

The  flexor  carpi  ulnaris,  forming  the  inner 
margin  of  the  muscles  of  the  fore-arm,  is  in 
contact  witli  the  fascia:  its  external  edge  touches 


368 


MUSCLES  OF  THE  FORE-ARM. 


the  flexor  communis  digitorum  sublimis.  The 
relation  of  this  muscle  to  the  ulnar  artery  has 
induced  some  anatomists  to  denominate  it 
muscle  satellite  de  I'artire  cubitale. 

In  addition  to  its  power  as  a  flexor  of  the 
hand  on  the  fore-arm,  this  muscle  adducts  the 
hand,  drawing  it  towards  the  mesial  line. 

b.  The  deep  layer  of  muscles. — These  are 
three  in  number,  the  flexor  longus  proprius 
pollicis,  flexor  communis  digitorum  profundus 
perforans,  and  the  pronator  quadratus.  A  por- 
tion of  the  supinator  radii  brevis  is  also  found 
in  it. 

1.  The  flexor  longus  proprius  pollicis, 
Scemm.  ( '  Radio -phalangettien  du  pouce, 
Chauss.)  This  muscle,  situated  most  exter- 
nally, arises  by  two  heads ;  one,  narrow,  rounded, 
tendinous,  and  fleshy,  from  the  inner  condyle 
of  the  humerus;  the  other,  broad  and  fleshy, 
from  the  front  of  the  radius,  below  the  insertion 
of  the  biceps  and  supinator  radii  brevis,  and 
from  the  interosseal  ligament,  extending  as  low 
down  as  the  insertion  of  the  pronator  quadratus. 
Its  tendon,  first  formed  on  its  internal  and 
anterior  edge,  descends  behind  the  annular 
ligament  of  the  wrist-joint,  and  taking  its 
course  between  the  two  heads  of  the  flexor 
brevis  pollicis,  is  inserted  into  the  last  phalanx 
of  the  thumb. 

This  muscle  is  covered  anteriorly  by  the 
supinator  radii  longus  and  extensor  carpi  radialis 
iongior,  except  at  the  lower  part,  where  it  is 
simply  covered  by  the  deep  fascia  on  which 
the  radial  artery  lies.  To  its  inner  side  is  the 
flexor  digitorum  profundus. 

This  muscle  is  a  flexor  of  the  last  phalanx 
of  the  thumb,  a  powerful  and  important  muscle 
in  grasping  objects. 

2.  Flexor  communis  digitorum  profundus 
perforans.  ( M. perforans,  Scemm.  M.  cubito- 
phalangettien  commun,  Chauss.)  arises  tendi- 
nous from  the  front  of  the  ulna  immediately 
below  the  insertion  of  the  brachialis  anticus 
into  the  tubercle  of  that  bone,  and  from  the 
same  as  low  down  as  the  pronator  quadratus  ; 
also  from  the  interosseous  ligament.  It  becomes 
tendinous  on  its  anterior  face  about  the  middle 
of  the  "ore-arm,  thus  presenting  a  smooth  and 
polished  surface  to  the  muscles  in  front  of  it : 
like  the  superficial  flexor,  it  forms  its  four 
tendons,  which,  after  traversing  the  palm  of 
the  hand  and  piercing  the  split  tendons  of  the 
superficial  flexor,  are  ultimately  inserted  into 
the  third  phalanx  of  each  of  the  fingers. 

This  muscle  has  the  flexor  longus  pollicis 
to  its  outer  side ;  the  flexor  carpi  ulnaris  to  its 
inner ;  and  the  flexor  carpi  radialis,  flexor  com- 
munis digitorum  sublimis  and  palmaris  longus, 
anterior  to  it. 

To  flex  the  fingers  on  the  hand,  commencing 
with  the  flexion  of  the  last  phalanx  on  the 
others,  and  the  whole  hand  on  the  fore-arm, 
constitutes  the  principal  action  of  this  muscle. 

3.  Pronator  quadratus,  Scemm.  ( Cubito- 
radial,  Chauss.)  This  muscle,  entirely  covered 
by  those  mentioned  above,  presents  a  beauti- 
ful appearance  on  their  removal,  from  the  ten- 
dinous surface  admitting  by  its  transparency 


the  colour  of  the  muscle  to  shine,  as  it  were, 
through  it. 

It  arises  from  the  ulna  about  an  inch  and  a 
half  above  the  wrist-joint,  occupying  exactly 
that  extent  of  the  surface  of  the  bone  with  its 
attachments  :  it  is  inserted  fleshy  into  the  lower 
part  of  the  radius. 

This  muscle,  simple  as  its  action  appears, 
that  of  rolling  the  radius  over  the  ulna,  per- 
forms a  most  important  part  in  those  easy  mo- 
tions of  the  hand  which  the  artist  uncon- 
sciously produces  when  he  is  engaged  sketching 
in  bold  and  flowing  lines  the  subject  of  his 
picture. 

To  the  surgeon  a  knowledge  of  the  attach- 
ments of  this  muscle  is  peculiarly  important, 
for  in  those  cases  in  which  the  radius  is  frac- 
tured near  its  lower  extremity  it  draws  the 
injured  bone  into  the  field  of  the  flexor  tendons, 
and  by  bringing  it  into  close  contact  with  the 
ulna,  produces  a  deformity  which  great  care 
will  alone  obviate. 

Posterior  antebrachial  region. — If  we  now 
look  to  the  posterior  part  of  the  fore-arm,  we  shall 
find  that  though  it  may  be  divided  into  radial 
and  ulnar  sections  like  the  anterior,  the  propor- 
tions between  them  will  be  very  different ;  for  one- 
fifth  of  the  transverse  diameter  of  the  arm  alone 
can  be  correctly  allotted  to  the  radial  region  in 
the  upper  part,  and  two-fifths  close  to  the  wrist- 
joint.  The  line  of  demarcation  between  these 
two  regions  is  accurately  formed  in  the  dissected 
arm  by  the  radial  edge  of  the  extensor  com- 
munis digitorum.  This  muscle,  like  those  on 
the  anterior  surface  of  the  arm,  is  wide  and 
muscular  above,  tendinous  and  comparatively 
narrow  below ;  and  hence  we  find  the  radial 
section  wider  below  than  it  is  above.  In  the 
ulnar  section,  we  have  the  extensor  communis 
digitorum  to  the  outer  side;  in  contact  with 
this  muscle,  on  its  ulnar  side,  is  the  extensor 
carpi  ulnaris.  This  muscle,  at  its  origin  at 
the  upper  part  of  the  arm,  is  narrow,  and  the 
space,  thus  yielded  as  it  were  by  its  form,  is 
occupied  by  the  anconeus,  which  forms  the 
boundary  of  this  region  on  the  ulnar  side. 
The  space  left  at  the  lower  part  of  the  arm, 
from  the  divergence  of  the  tendons  of  the 
extensor  carpi  ulnaris  and  extensor  communis 
digitorum,  permits  a  view  of  the  indicator. 
The  radial  section  contains  at  its  upper  part 
solely  the  extensor  carpi  radialis  brevior ;  but 
at  the  upper  part  of  the  middle  of  the  arm,  we 
have  sliding  into  it  from  behind  the  extensor 
communis  digitorum,  the  extensor  ossis  meta- 
carpi  pollicis,  and  extensor  primi  internodii 
pollicis.  These  pursue  their  course  obliquely 
across  the  radial  section  till  they  reach  the  outer 
edge  of  the  arm.  Lower  down  than  these 
muscles  and  scarcely  in  contact  with  their 
inferior  edges,  we  discover  the  tendon  of  the 
extensor  secundi  internodii  pollicis  likewise 
emerging  from  beneath  the  extensor  communis 
digitorum. 

a.  Superficial  muscles  of  the  posterior  anti- 
brachial  region.  —  1.  Anconeus  ( epicondylo- 
cubital,  Chauss.)  though  usually  described  as 
a  distinct  muscle,  is,  in  reality,  a  continuation 


MUSCLES  OF  THE  FORE-ARM. 


3C9 


of  the  triceps  extensor  cubiti:  the  fibres  of  each 
are  perfectly  continuous,  and  there  is  no  line 
of  demarcation  between  them.  An  artificial 
boundary  may  be  made  by  drawing  a  line 
horizontally  inwards  when  the  fore-arm  is  ex- 
tended on  the  upper  arm,  between  the  outer 
condyle  of  the  os  humeri  and  the  olecranon 
process  of  the  ulna.  With  this  view  of  the  limit 
of  the  upper  edge  of  the  anconeus,  it  may  be 
described  as  a  triangular  muscle,  the  base  above 
and  the  apex  below.  This  muscle  arises  ten- 
dinous from  the  back  part  of  the  outer  condyle, 
its  external  and  anterior  edge  continuing  ten- 
dinous almost  to  its  insertion ;  its  superior 
fleshy  fibres  pass  transversely  inwards  and 
backwards,  to  be  inserted  into  the  fascia  of  the 
fore-arm  and  also  into  the  olecranon ;  the  middle 
and  inferior  fibres  pass  backwards  to  the  ulna 
with  various  degrees  of  obliquity,  and  occupy 
by  their  insertion  about  one-third  of  the  bone 
from  its  superior  extremity. 

This  muscle  is  a  simple  extensor  of  the 
fore-arm. 

2.  Extensor  carpi  ulnaris,  (ulnaris  exter- 
nus,  Scemm.;  cubito  sus-metucarpien,  Chauss.) 
arises  from  the  back  part  of  the  outer  con- 
dyle between  the  anconeus  and  the  extensor 
communis  digitorum,  with  which  latter  muscle 
it  is  so  intimately  connected  that,  more  strictly 
speaking,  it  ought  to  be  said  to  arise  in  a 
common  tendon.  Connected  by  a  narrow 
origin  to  the  humerus  it  gradually  expands, 
and  about  the  middle  of  the  fore-arm,  a  tendon 
being  formed  in  the  centre,  it  exhibits  in  its 
further  course  a  well-marked  specimen  of  the 
double  penniform  muscle.  The  tendon  of  this 
muscle,  in  its  passage  towards  the  wrist-joint, 
runs  in  an  especial  groove  appropriated  for  its 
reception  in  the  back  part  of  the  ulna ;  it  ter- 
minates by  being  inserted  in  the  metacarpal 
bone  supporting  the  little  finger.  The  extensor 
carpi  ulnaris  is  more  or  less  connected  with  the 
fascia  throughout  the  whole  of  the  upper  arm. 

This  muscle  extends  the  first  row  of  carpal 
bones  on  the  second  and  the  whole  hand  on 
the  fore-arm ;  it  is  likewise  an  adductor  of  the 
hand. 

3.  Extensor  communis  digitorum  ( epicondylo 
sus-phalangettien  commun,  Chauss.  Dumas) 
arises  from  the  back  part  of  the  outer  condyle 
in  common  with  the  extensor  carpi  ulnaris  on 
its  outer  side,  and  the  extensor  carpi  radialis 
brevior  on  its  inner  side.  The  connexion  of 
this  muscle  to  the  os  humeri  is  extremely 
narrow  in  comparison  with  the  width  of  the 
muscle  in  the  centre  of  the  fore-arm.  In  its 
ample  attachment  to  the  fascia  it  resembles  the 
flexor  ulnaris,  and,  like  it,  is  a  penniform 
muscle.  We  not  unfrequenly  find  a  portion 
of  this  muscle  so  entirely  distinct  from  the 
rest  that  anatomists  have  occasionally  described 
it  as  a  separate  muscle,  under  the  name  of  the 
extensor  proprius  minimi  digiti ;  for  being 
inserted  into  the  little  finger,  it  possesses  the 
power  of  extending  that  portion  of  the  hand. 
It  passes  behind  the  posterior  annular  ligament 
of  the  wrist-joint,  splits  into  four  tendons, 
which,  expanding  on  the  back  part  of  the 
phalanges  of  the  four  fingers,  convey  the  power 

VOL.  II. 


of  the  muscle  to  each  phalanx  in  an  equal 
degree.  The  tendons  of  this  muscle  in  their 
passage  behind  the  annular  ligament  of  the 
wrist-joint  are  clothed  by  a  synovial  membrane 
(reflected  like  all  other  synovial  membranes)  so 
as  to  form  a  perfect  purse  or  bursa.  Both 
these  muscles  are  intimately  connected  upon 
their  under  surface  at  the  upper  part  of  the 
arm,  with  the  aponeurosis  covering  fhe  supi- 
nator radii  brevis. 

This  muscle  is  an  extensor  of  the  fingers  and 
the  hand  on  the  fore-arm. 

4.  Extensor  carpi  radialis  brevior,  (radialis 
externus  brevior,  Soemm.  Epicondylo  sus- 
mctacurpien,  Chauss.  Dumas),  with  a  small 
portion  of  the  extensor  carpi  radialis  longior, 
occupies  the  radial  division  of  the  poste- 
rior superficial  antibrachial  region.  This 
muscle  arises  from  the  outer  condyle  by  a 
flattened  narrow  origin,  in  common  with  the 
extensor  communis  digitorum,  being  overlapped 
on  its  outer  side  by  the  extensor  carpi  radialis 
longior.  This  muscle,  like  most  we  have 
described  in  the  fore-arm,  swells  out  towards 
the  centre,  where,  gradually  becoming  tendi- 
nous, it  again  diminishes  in  size.  It  passes  the 
same  groove  in  the  radius  as  the  extensor  carpi 
radialis  longior,  and  terminates  by  an  insertion 
into  the  metacarpal  bone  of  the  middle  finger. 
The  under  surface  of  this  muscle  is  tendinous 
at  the  upper  part  of  the  arm,  which  permits  it 
to  play  without  friction  upon  the  smooth  and 
tendinous  face  of  the  supinator  radii  brevis 
with  which  it  is  in  contact. 

This  muscle  acts  as  an  extensor  of  the  hand 
on  the  fore-arm  and  an  abductor. 

b.  Deep  muscles  of  the  posterior  antibrachial 
region. — The  muscles  in  this  region  com- 
mencing above,  are  the  supinator  radii  brevis, 
the  extensor  ossis  metacarpi  pollicis,  the,  exten- 
sor primi  internodii  pollicis,  the  extensor 
secundi  internodii,  and  the  indicator. 

1 .  Supinator  radii  brevis,  ( epicondylo-rcidial, 
Chauss.)  arises  tendinous  from  that  portion  of 
the  outer  and  back  part  of  the  ulna,  unoccupied 
by  the  insertion  of  the  anconeus;  it  arises  also 
from  the  back  part  of  the  outer  condyle,  covered 
at  its  origin  from  the  outer  condyle  by  the 
extensor  communis  digitorum  and  by  the  exten- 
sor carpi  radialis  brevior.  Its  posterior  and 
external  surface  is  tendinous,  its  internal  fleshy, 
and  it  embraces  so  much  of  the  upper  extremity 
of  the  radius,  as  to  form  an  imperfect  tube. 
Anteriorly  we  find  it  partly  overlapping  the 
tubercle  of  that  bone,  with  the  tendon  of  the 
biceps  which  is  inserted  into  it.  Between  these 
and  the  under  surface  of  the  muscle  is  a  large 
and  distinct  bursa  mucosa ;  it  covers  rather 
more  than  the  upper  third  of  the  radius  by  its 
insertion,  extending  as  low  down  as  the  pro- 
nator radii  teres. 

This  muscle  is  the  main  agent  in  effecting 
the  supination  of  the  hand. 

2.  Extensor  ossis  metacarpi  pollicis,  (ab- 
ductor longus  pollicis  manus,  Scemm.  cubito- 
radi  sus-rnetacarpien,  Dumas,)  arises  from  the 
ulna,  interosseous  ligament,  and  the  back  part  of 
the  radius,  opposite  the  insertion  of  the  pronator 
radii  teres,  having  to  its  outer  side  the  supi-  '1 

2  B 


FOURTH  PAIR  OF  NERVES. 


nator  radii  brevis,  to  its  inner  the  extensor  primi 
internodii  pollicis.  It  is  covered  posteriorly  by 
the  extensor  communis  digitorum  and  extensor 
carpi  ulnaris.  Gliding  downwards  and  out- 
wards from  beneath  these  muscles  and  becoming 
tendinous  on  its  under  surface,  it  slips  over  the 
lower  third  of  the  posterior  face  of  the  radius, 
and  then  running  in  a  groove  on  the  outer  side 
of  that  bone,  common  to  it  and  the  next  men- 
tioned muscle,  is  ultimately  inserted  into  the 
metacarpal  bone  of  the  thumb. 

The  action  of  this  muscle  is  to  extend  the 
metacarpal  bone  of  the  thumb,  which  corre- 
sponds as  regards  its  capacity  for  motion,  with 
the  phalanges  of  the  fingers. 

3.  Extensor  primi  internodii  ( extensor 
minor  pollicis  munus,  Scemm.;  cubito  sus- 
phalangettien  du  police,  Chauss.)  is  a  very  small 
muscle  compared  with  the  last,  though  varying 
much  in  size  in  different  subjects.  It  lies 
between  the  extensor  ossis  metacarpi  pollicis 
and  the  extensor  secundi  internodii,  passing 
through  the  same  groove  in  the  radius  as  the 
extensor  ossis  metacarpi  pollicis,  it  becomes 
inserted  into  the  first  phalanx  of  the  thumb. 

4.  The  extensor  secundi  internodii  pollicis 
( extensor  major  pollicis  munus,  Scemm. ;  cubito 
sus-phalangettien  du  pouce,  Chauss.) — This 
muscle  is  usually  larger  than  the  former;  it 
arises  fleshy  from  the  ulna  and  interosseous 
ligament ;  becoming  tendinous  in  its  centre,  it 
presents  the  same  penniform  appearance  referred 
to  above.  The  groove  in  the  radius  which  is 
narrow  and  deep,  this  tendon  alone  being 
lodged  in  it.  It  is  situated  between  that  for 
the  two  radial  extensors  and  the  broad  and 
hollow  one  for  the  common  extensors  and 
indicator.  Crossing  on  the  back  of  the  wrist 
the  radial  extensors  it  is  finally  inserted  into 
the  second  phalanx  of  the  thumb.  This  mus- 
cle is  entirely  covered  in  the  fore-arm  by  the 
common  extensors  of  the  fingers. 

5.  The  indicator  (cubito  sus-phalangettien 
de  I'index )  occupies  the  remaining  portion  of 
the  posterior  interosseal  space.  Like  the  three 
last  described  muscles  it  is  penniform,  and 
arises  fleshy  from  the  ulna  and  interosseous 
ligament,  it  descends  to  the  hand  and  passes 
through  the  same  groove  at  the  back  of  the 
radius  as  that  of  the  extensor  communis  digi- 
torum, it  is  inserted  into  the  posterior  surface 
of  the  three  phalanges  of  the  index  finger. 
This  muscle  is  entirely  concealed  by  the  exten- 
sor carpi  ulnaris  and  extensor  communis  digi- 
torum. 

The  names  of  this  and  the  two  preceding 
muscles  indicate  their  actions. 

For  Bin-iocbaphy,  see  Anatomy,  (Intro- 
duction.) 

(Samuel  Solly.) 

FOURTH  PAIR  OF  NERVES  (nervus 
trochleuris,  s.  patheticus ). — The  fourth  pair  is 
the  most  slender  of  the  encephalic  nerves.  They 
are  intermediate  in  the  'Order  of  succession  to 
the  third  or  motor  oculiand  the  fifth  nerves,  and 
hence  the  name.  Each  nerve  is  attached  at  its 
encephalic  extremity  to  the  lateral  part  of  the 


superior  surface  of  the  anterior  medullary 
velum  or  valve  of  Vieussens,  immediately  behind 
the  testes  or  the  posterior  of  the  tubercula 
quadrigemina.  It  is  divided  at  its  attachment, 
for  the  most  part,  into  two  roots,  inserted  at  a 
little  distance  from  each  other,  one  close  to  the 
testes,  the  other  posterior  to  it.  Occasionally  it 
has  but  one  root  and  sometimes  even  three. 
Gall  and  Spurzheim*  are  of  opinion  that  the 
nerve  might  be  traced  to  a  more  remote  point, 
and  according  to  Mayof  "  its  fibrils  appear  to 
pass  through  the  filaments  of  the  pillar  of  the 
valve,  and  in  part  to  arise  from  the  back  part 
of  the  medulla  oblongata." 

The  nerve  is  concealed  at  its  insertion  by  the 
superior  vermiform  process  of  the  cerebellum, 
and  it  is  not  immediately  provided  with  neu- 
rilemma, and  hence,  as  also  because  of  its 
delicacy,  it  is  very  easily  broken  off. 

Its  course  within  the  cranium  is  circuitous 
and  long,  longer  than  that  of  the  other  nerves. 
It  passes  outward,  downward,  and  forward : 
it  first  descends  external  to  the  superior  peduncle 
of  the  cerebellum  (the  processus  a  cerebello  ad 
testes),  between  it  and  the  vermiform  process, 
then  becomes  invested  with  arachnoid  mem- 
brane and  free,  and  runs  round  the  lateral  part 
of  the  crus  cerebri,  above  the  superior  margin 
of  the  pons  Varolii,  and  beneath  the  free  edge 
of  the  tentorium  cerebelli,  until  it  reaches  the 
posterior  clinoid  process  of  the  sphenoid  bone; 
it  then  enters  the  outer  wall  of  the  cavernous 
sinus  between  the  points  of  attachment  of  the 
tentorium,  and  is  transmitted  through  a  canal 
in  the  dura  mater,  by  which  the  wall  is  formed, 
forward  to  the  foramen  lacerum  of  the  orbit. 
It  does  not  enter  the  sinus,  being  contained  in 
a  canal  in  its  outer  wall. 

At  the  posterior  part  of  the  sinus  the  nerve 
is  situate  beneath  the  third,  between  it  and  the 
first  division  of  the  fifth  nerve;  but  at  the 
anterior,  and  as  they  are  about  to  pass  into  the 
orbit,  the  fourth  and  frontal  branch  of  the  fifth 
are  both  above  the  third,  the  fourth  internal 
and  a  little  superior  to  the  frontal. 

The  nerve  lastly  enters  the  orbit  through  the 
superior  part  of  the  foramen  lacerum  in  com- 
pany with  the  frontal,  above  the  levator  palpebral 
muscle,  and  immediately  beneath  the  roof  of 
the  region.  Having  entered,  it  runs  forward 
and  inward,  gains  the  surface  of  the  superior 
oblique  muscle,  and  attaching  itself  to  it  upon 
its  superior  aspect,  about  its  middle,  it  divides 
into  filaments,  which  are  all  distributed  to  the 
muscle. 

The  fourth  nerve  does  not  give  off  any  branch 
during  its  course  to  the  oblique  muscle,  unless, 
at  times,  first  a  filamentdescnbed  by  Cruveilhier, 
and,  according  to  him,distributed  to  the  tentorium 
cerebelli.  This  filament  arises  from  the  nerve 
while  traversing  the  wall  of  the  cavernous  sinus, 
runs  backward  into  the  substance  of  the  ten- 
torium, and  divides  into  two  or  three  branches: 
Cruveilhier  calls  it  "  the  branch  of  the  tento- 
rium." Secondly,  according  to  both  Swan  and 
Cruveilhier,  the  fourth  nerve  gives  off  a  fila- 

*  Anatomie  Ju  Systeme  nerveux. 
f  Physiology. 


GANGLION. 


371 


ment  to  the  lachrymal  branch  of  the  fifth. 
Before  its  entrance  into  the  orbit  the  nerve 
receives  a  filament  from  the  sympathetic,*  and 
at  or  immediately  after  entering,  it  receives  one 
also  from  the  frontal  branch  of  the  fifth,  by  the 
accession  of  which  it  is  sensibly  increased  in 
size.  It  is  very  closely  connected  to  the  frontal 
itself  at  the  back  of  the  orbit. 

Upon  the  fourth  nerve  the  power  of  the 
superior  oblique  muscle  is  considered  to  depend. 
It  is  remarkable  that  this  muscle  should  be 
provided  with  an  especial  nerve,  differing, 
apparently,  so  much  in  its  encephalic  relations 
from  those  by  which  the  others  are  supplied  ; 
but  the  theories  which  have  been  advanced 
upon  the  subject  are  as  yet  so  unsubstantial, 
that  we  think  it  better  to  leave  them  untouched. 
(See  Orbit,  muscles  of  the). 

The  nerve  exists  with  similar  relations  in  all 
the  veriebrata. 

For  the  Bibliography,  see  Nerve. 

(B.  Alcock.) 

GANGLION,  (Gr.  yayyXiov,  Germ.  Nerven 
Knoten.)— This  term  is  applied  to  several  dis- 
tinct structures  :  to  the  nodules  placed  on  cer- 
tain nerves,  to  the  lymphatic  glands  or  gan- 
glions, to  certain  bodies,  as  the  thyroid,  the 
thymus,  &c,  which  have  been  called  by  some 
anatomists  vascular  ganglions,  and  lastly,  in 
surgical  language,  to  the  enlargement  of  the 
synovial  bursas.  It  is,  however,  most  gene- 
rally applied  to  the  ganglions  of  the  nerves; 
but  of  late  years  many  anatomists,  who  con- 
ceive that  the  various  masses  of  grey  matter 
met  with  in  the  encephalon  and  spinal  chord 
are,  together  with  the  ganglia  of  the  nerves, 
sources  of  nervous  power,  have  extended  to 
those  masses  the  general  term  of  ganglion. 
Although  there  can  be  no  doubt  that  the 
analogy  has  a  real  foundation,  and  that  this 
application  of  the  word  is  both  convenient  and 
correct,  it  is  nevertheless  proposed,  in  obe- 
dience to  custom,  to  retain  the  old  and  more 
limited  sense  of  the  term  ganglion,  and  to 
devote  the  present  article  to  the  structure  of 
the  ganglions  of  the  spinal  and  sympathetic 
nerves,  referring  the  reader  for  an  account  of 
the  functions  of  these  bodies  to  the  articles 
Nervous  System  and  Sympathetic  Nerve. 

The  nervous  ganglions  consist  of  a  number 
of  oval  or  roundish  organs  connected  with 
certain  nerves,  and  placed  deeply  in  the  trunk 
of  the  body,  to  which  they  are  confined,  being 
situated,  with  the  exception  of  those  of  the 
head,  in  the  immediate  vicinity  of  the  vertebral 
column.  Their  number  and  size  are  subject  to 
variation,  not  only  in  different  persons,  but  even 
on  the  two  sides  of  the  same  individual;  the 
following  is  the  enumeration  which  approaches 
nearest  to  the  truth :  thirty  on  each  side  of 
the  body,  placed  on  the  posterior  roots  of  the 
spinal  nerves ;  one  on  each  side,  situated  on 
the  larger  origin  of  the  fifth  pair;  the  ganglions 
of  the  great  sympathetic  consisting  of  the  follow- 
ing, connected  on  each  side  of  the  body  with  what 

*  See  Pauli  in  Muller's  Archiv.  for  1834. 


is  regarded  as  the  trunk  of  this  nerve,  viz.  three 
cervical,  twelve  dorsal,  three  to  four  or  five 
lumbar,  three  to  five  sacral ;  to  these  we  must 
add  some  large  masses  placed  near  the  mesial 
plane,  viz.  two  semilunar,  three  or  four  coeliac 
ganglions,  and  one  cardiac  ganglion,  first  de- 
scribed by  Wrisberg,  but  which  is  occasionally 
deficient ;  and  lastly,  forming  a  part  of  the  great 
sympathetic,  the  ophthalmic,  the  sphenopala- 
tine, the  otic,  and  the  submaxillary  ganglions, 
and  a  small  body  usually  met  with  in  the  caver 
nous  sinus,  the  cavernous  ganglion.  M.  Hip. 
Cloquet  has  described  in  rather  vague  terms  a 
small  reddish  mass  placed  in  the  anterior 
palatine  canal,  which  he  calls  the  nasopalatine 
ganglion  ;  but  Arnold,  Cruveilhier,  and  others 
deny,  and  with  good  reason,  the  existence  of 
this  body.  A  gangliform  enlargement  is  con- 
stantly seen  on  the  commencement  of  the  ner- 
vus  vagus,  and  a  second  lower  down ;  a 
similar  swelling  is  also  placed  on  the  glosso- 
pharyngeal nerve  (g.  petrosum). 

Professor  Miiller  of  Berlin  has  discovered 
above  this  enlargement  a  true  ganglion  on  the 
the.  glosso-pharyngeal  (ganglion  jugulare  nervi 
glosso-pharyngei),  occupying  half  or  two-thirds 
of  the  trunk  of  the  nerve,  and  being  precisely 
to  that  nerve  what  the  Intervertebral  ganglion 
and  the  Gasserian  are  to  the  spinal  nerves  and 
the  fifth  pair.  My  colleague  Mr.  Walker  has 
shown  me  this  ganglion,  which  is  placed  in  the 
upper  part  of  the  foramen  lacerum  basis  cranii 
posterius,  and  corresponds  to  the  above  descrip- 
tion.* 

Arnold  has  further  noticed  that  at  the  junc- 
tion of  the  superior  twig  of  the  Vidian  nerve, 
or  nervus  innominatus,  with  the  facial  nerve, 
there  is  a  gangliform  swelling.f 

Mayer  has  discovered  a  minute  posterior 
root  of  the  sublingual  nerve,  with  a  ganglion 
on  it,  in  some  mammalia  (ox,  dog,  pig),  and 
in  one  instance  in  man. 

Thus  the  total  number  of  ganglions  in  the 
human  body  amounts  to  about  one  hundred 
and  twenty-seven,  exclusive  of  the  gangliform 
enlargements  on  the  pneumo-gastric,  glosso- 
pharyngeal, and  the  facial  nerves. 

These  bodies  have  been  variously  arranged . 
by  writers  on  this  subject ;  thus  by  WeberJ 
they  are  divided  into  ganglions  of  reinforce- 
ment, such  as  those  on  the  spinal  nerves,  and 
into  ganglions  of  origin,  of  which  those  of  the 
sympathetic,  the  ophthalmic,  and  the  spheno- 
palatine are  examples;  whilst  Wutzer,§  classing 
them  according  to  their  situation  and  relations, 
considers  that  there  are  three  orders,  1.  the 
cerebral  ;  2.  the  spinal  ;  3.  the  vegetative  : 
the  first  comprises  the  Gasserian  ganglion,  the 
ophthalmic,  and  the  ganglion  of  Meckel,  to 
which  must  be  added  the  otic  ganglion  of  Ar- 

*  This  very  interesting  discovery  confirms  the 
opinion  that  the  glosso-pharyngeal  is,  like  the  spi- 
nal and  the  fifth,  a  compound  nerve  of  motion  and 
sensation.  See  Medizinische  Vereins-Zeitune. 
Berlin,  1833. 

t  Icones  Nerv.  Corp.  p.  2.  tab.  ii.  and  vii. 

t  Anat.  Compar.  nervi  sympath. 

§  De  corp.  hum.  ganglior.  fabrica  atquc  usu, 
p.  52. 


372 


GANGLION. 


nold  ;  in  the  second  order  are  enumerated  the 
thirty  spinal  ganglions  and  the  ganglionic  en- 
largement of  the  nervus  vagus  and  glosso-pha- 
ryngeus ;  in  the  third  division  are  included  the 
ganglions  of  the  sympathetic  nerve. 

The  former  of  these  arrangements  is  objec- 
tionable, because  offices  are  assigned  to  the 
ganglions  the  existence  of  which  has  not  been 
ascertained  ;  and  the  latter  is  so  far  erroneous 
that  in  this  classification  the  ganglion  of  the 
fifth  pair  is  separated  from  the  spinal,  to  which 
it  is  undoubtedly  similar;  whilst  the  ophthalmic 
and  spheno-palatine  are  as  incorrectly  divided 
from  the  system  of  the  sympathetic* 

In  endeavouring  to  detect  that  which  con- 
stitutes the  essential  difference  among  these 
numerous  bodies,  we  ought  to  pay  special 
attention  to  the  character  of  the  nerves  which 
are  attached  to  the  ganglions.  Taking  this  as 
the  only  rational  guide,  I  should  refer  them  to 
two  classes.  1.  Those  which  are  placed  on 
sentient  nerves,  comprising  the  Gasserian,  the 
ganglion  .of  the  glosso-pharyngeus,  and  the 
spinal  ganglions  The  gangliform  enlargement 
of  the  nervus  vagus  should  be  referred  to  this 
order,  inasmuch  as  there  can  be  little  doubt, 
although  this  at  present  is  not  proved,  that  this 
nerve  is  compounded,  like  the  spinal  nerves,  of 
motor  and  sentient  fibrils,  a  surmise  supported 
by  the  distribution  of  the  vagus,  and  still  more 
by  the  interesting  discovery  of  my  friend 
Mr.  Solly,  of  the  existence  of  certain  motor 
fibrils  in  the  exact  part  of  the  medulla  oblon- 
gata, whence  this  nerve  arises.f 

2.  Those  which  have  connected  with  them 
both  motor  and  sentient  nerves,  and  are,  as  I 
believe,  always  in  relation  with  contractile  and 
sensitive  structures :  J  those,  namely,  of  the 
great  sympathetic  nerve,  comprising  the  cer- 
vical, the  dorsal,  lumbar,  and  sacral,  together 
with  the  cardiac,  the  semilunar  and  coeliac, 
also  the  ophthalmic,  the  spheno-palatine,  the 
otic,  submaxillary,  and  cavernous. 

These  classes  nearly  correspond  with  the 

*  The  following  is  the  classification  of  Mailer  : 
1.  Ganglia  of  the  posterior  roots  of  the  spinal 
nerves,  of  the  larger  portion  of  the  nervus  trige- 
minus, of  the  nervus  vagus,  and  ganglion  jugulare 
nervi  glosso-pharyngei.  2.  Ganglia  of  the  great 
sympathetic.  3.  Ganglia  which  occur  at  the  points 
of  junction  of  the  cerebro-spinal  nerves  with  the 
branches  of  the  sympathetic,  comprising  ganglion 
petrosum  nervi  glosso-pharyngei,  intumescentia 
gangliformis  nervi  facialis,  ganglion  spheno-pala- 
tinum,  ciliare,  oticum  (probably).  To  which  should 
bo  added  ganglion  submaxillare.  Handbuch  der 
Physiol,  der  Menschen.  Erster  Band.  p.  588. 

t  According  to  the  present  opinion,  the  whole  of 
the  fibres  belonging  to  the  nervus  vagus  enter  into 
the  ganglion;  and  Bischoff  imagines  that  this  nerve 
derives  its  motor  portion  from  the  spinal  accessory. 
The  intimate  relations  between  these  two  nerves 
require  further  investigation. 

X  It  cannot  be  too  often  repeated  that  sensibility, 
or,  to  speak  more  correctly,  the  capability  of  being 
excited  by  the  contact  of  a  physical  agent,  may 
exist  without  being  accompanied  wiih  conscious- 
ness :  the  inner  surface  of  the  heart,  of  the  blood- 
vessels, and  intestine  are  as  capable  of  being  ex- 
cited as  the  skin  or  the  retina  ;  but  the  impressions 
which  they  receive  are  not  usually  perceived  by  the 
mind. 


simple  and  compound  ganglions  of  Scarpa*  and 
Meckel.f 

There  are  occasionally  found  ganglia  on 
other  nerves ;  thus,  Mr.  Swan  X  has  noticed  one 
on  the  posterior  spinal  nerve,  where  it  is 
placed  under  the  extensor  tendons  of  the 
wrist.  My  friend  Mr.  Pilcher  has  also  found 
in  two  subjects  a  gangliform  enlargement  on 
the  internal  nasal  nerve,  where  it  is  lodged  on 
the  ethmoidal  bone. 

It  is  necessary  to  remark  that  although  the 
ganglia  of  the  first  class  are  placed  on  certain 
of  those  nerves  which  are  commonly  regarded 
as  being  subordinate  simply  to  sensation,  yet 
the  highly  important  observations  of  Dr.  M. 
Hall,§  which  have,  I  conceive,  opened  an  en- 
tirely new  field  in  physiology,  render  it  doubt- 
ful that  those  bodies  are  essential  to  the  exer- 
cise of  sensation. 

Organization. — Although  the  cerebro-spinal 
and  sympathetic  ganglia  present  some  impor- 
tant peculiarities  when  contrasted  with  each 
other,  particularly  as  regards  the  proportions 
of  the  grey  and  fibrous  substances,  still  as 
both  classes  possess  essentially  the  same  struc- 
ture, they  may  with  propriety  be  considered  in 
a  collective  manner. 

Every  ganglion  contains  two  totally  distinct 
substances  which  have  a  close  relation  to,  and 
are,  I  believe,  identical  with  the  grey  and 
fibrous  matters,  constituting  the  encephalon 
and  other  parts  of  the  nervous  system.  It  is 
true  that  the  appearance  of  these  bodies  is  in 
many  respects  dissimilar  to  that  of  the  brain  ; 
but  at  length  it  is  universally  admitted  that 
differences  in  mere  physical  properties  are 
unimportant,  and  do  not  constitute  any  test  as 
to  tlve  essential  structure  of  an  organ.  In  the 
present  instance  the  diversity  may  very  readily 
be  understood  when  the  difference  of  situation 
is  considered.  The  cerebral  organ  is  enclosed 
in  a  cavity,  the  cranium,  formed  of  some  of 
the  strongest  bones  of  the  skeleton,  and  hence, 
being  effectually  defended  from  the  effects  of 
motion  and  external  pressure,  all  its  parts  are 
soft  and  delicate ;  whilst  the  ganglia,  placed 
on  bones  which  move  on  each  other,  slightly  it 
is  true,  are  exposed  to  external  compression, 
and  consequently  a  much  firmer  texture  is 
required.  It  is  for  this  reason  that  these 
bodies  are  invested  in  a  dense  fibrous  capsule, 
which  is  to  them  what  the  cranium  is  to  the 
encephalon,  and  which  furnishes  in  addition  a 
number  of  internal  processes  surrounding  each 
fibril,  and  sustaining  the  spherical  masses 
of  grey  matter.  The  difficulty  of  detecting 
the  intimate  texture  is  by  these  means  greatly 
increased  ;  but  as  it  is  so  similar  to  that  of  the 
cerebrum,  it  is  desirable  to  examine  the  con- 
stituent parts  according  to  the  order  observed 
in  investigating  that  organ. 

I.  Reddish  grey  matter. — The  quantity  of 
this  substance,  often  called  the  peculiar  matter 
of  the  ganglions,  but  which,  as  I  have  stated, 

*  Anat.  Annotat.  liber  primus.  De  nerv.  gang, 
et  plex.  p  9. 

t  Man.  d'Anat.  i:.  i.  ^231. 

i  On  the  Nerves,  pi.  xxii.  fig.  3. 

§  Lcct.  on  the  Nerv.  Sys.  183b'. 


GANGLION. 


373 


is  possessed  by  those  bodies  in  common  with 
the  brain  and  spinal  chord,  is  very  considerable, 
constituting  apparently  the  largest,  and  cer- 
tainly the  most  essential  part  of  the  ganglion. 
It  is  so  intimately  connected  with  the  fibres 
that  these  latter  appear  as  if  they  were  incrusted, 
being  surrounded  in  every  direction  by  this 
greyish  matter;  but  although  this  intimate 
intermixture  is  very  evident,  no  fibrils  can  be 
perceived  actually  terminating  in  or  arising 
from  the  grey  matter.  A  section  of  one  of  the 
sympathetic  ganglia,  the  first  cervical  for  ex- 
ample, displays  this  incrustation  of  the  fibres 
and  the  interposition  between  them  of  rounded 
masses  of  the  grey  matter ;  but  the  Gasseiian 
is  in  many  respects  the  most  favourable  for  ex- 
amination. 

Much  difference  of  opinion  exists  concerning 
the  true  nature  of  this  substance.  Scarpa  con- 
tends that  it  is  not  analogous  with  the  grey  matter 
of  the  brain,  but  that  it  consists  of  a  fiocculent 


a,  a,  Fasciculi  of  splanchnic  nerve. 

b,  b,  Fibres  running  through  the  ganglion. 

c,  c,  Branches  collected   from   the   former,  and 

emerging. 

This  juicy  or  gelatinous  substance,  which  is 
met  with  in  the  spinal  as  well  as  in  the  sympa- 
thetic ganglia,  does  not,  however,  according 
to  Lobstein,  appear  to  be  an  essential  part  of 
the  organization,  as  it  varies  in  its  proportion 
in  different  ganglia,  and  may  even  be  absent ; 
nor,  it  is  said,  can  it  be  assimilated  with  the 
grey  matter  of  the  brain. 

Ehrenberg  also  controverts  the  opinion  that 
the  ganglia  resemble  the  grey  part  of  the  brain  ; 
but  although  he  has  found  by  microscopical 
inspection,  that  these  bodies  contain  an  over- 


tissue  loaded  with  a  mucilaginous  fluid,  which 
becomes  oily  in  obesity,  and  watery  and  abun- 
dant in  anasarca.  The  accumulation  of  fat  in 
the  true  ganglionic  tissue  has,  however,  been 
denied  by  Beclard,  Wutzer,  and  others.  Ac- 
cording to  Bichat,  whose  opinions  must  always 
command  our  respect,  "  the  ganglions  have  a 
colour  very  different  from  that  of  the  nerves. 
They  present  a  soft  spongy  tissue,  somewhat 
similar  to  the  lymphatic  glands,  but  which  has 
nothing  in  common  either  with  the  cerebral 
substance  or  with  that  of  the  nerves."  It  is 
stated  by  Lobstein,  who  has  published  one  of 
the  latest  and  most  minute  accounts  of  the 
structure  and  diseases  of  the  sympathetic 
nerve,*  that  he  has  observed  lying  contiguous 
to  the  white  and  filamentous  tissue  another 
substance  presenting  a  fiocculent  appearance, 
with  globules  interspersed  (muteries  vel  sub- 
stantia orbicularis  tomentosa ),  and  which  he 
regards  as  the  second  material  of  the  ganglia. 


d,  d,  Fiocculent  or  orbicular  substance  placed  be- 

tween and  applied  to  fibres. 

e,  e,  Foramina  perforating  the  ganglion. 

whelming  proportion  of  large  varicose  tubes, 
similar  to  those  of  the  fibrous  portion  of  the 
brain,  yet  he  has  also  shewn  that  they  possess 
minute  varicose  fibres  like  those  of  the  grey 
substance  ;  and  what  particularly  is  deserving 
of  notice,  he  has  detected  in  the  muscles  of 
the  fibres  granules  similar  to  those  which  are 
found  in  the  cervical  portion  of  the  brain.f 

*  De  Nervi  Sympath.  Humani,  fabrica,  usu,  ct 
morbis,  p.  66. 

t  Structur  des  Seelenorgans  bci  Menschen  uud 
Thiercn,  Berlin,  1836,  p.  31. 


Fig.  170. 


Semilunar  ganglion,  twice  the  natural  lixe. 


374 


GANGLION. 


Notwithstanding  these  and  other  high  au- 
thorities, the  researches  of  many  recent  writers, 
which  have  thrown  so  much  new  and  valuable 
light  on  the  mutual  relations  of  the  component 
parts  of  the  nervous  system,  leave  little  room 
for  doubting  the  identity  of  these  two  sub- 
stances. The  analogy  of  the  whole  nervous 
system  tends  to  prove  that  this  peculiar  matter 
is  nothing  else  than  the  grey  substance ;  in  the 
Gasserian  ganglion,  indeed,  the  resemblance  is 
so  striking  that  no  doubt  of  their  identity  can 
be  entertained.  This  view  of  the  subject  was 
taken  by  Winslow,  Johnstone,  and  others; 
and  lately  the  existence  of  grey  matter  has 
been  admitted  by  Dr.  Fletcher,  an  assumption, 
indeed,  which  is  the  basis  of  his  hypothesis, 
that  the  ganglionic  system  of  nerves  is  the  im- 
mediate seat  of  irritability.* 

II.  Fibres. — This  is  a  most  important  branch 
of  the  present  inquiry,  because  a  knowledge 
of  the  connexions  of  these  bodies  with  the  other 
parts  of  the  nervous  system  and  with  each 
other,  as  well  as  of  the  internal  disposition  of 
their  fibres,  is  indispensable  to  the  investigation 
of  their  functions.  The  subject  may  be  re- 
solved into  two  questions,  a.  What  is  the 
arrangement  of  the  fibres  in  the  ganglia  ? 
b.  What  is  the  nature  of  the  fibres  which  arc 
connected  with  the  ganglia  ? 

a.  The  internal  disposition  of  the  nervous 
filaments,  owing  to  the  very  intimate  relations 
subsisting  betweeu  them  and  the  grey  matter, 
is  difficult  to  determine;  and  hence  it  has 
happened  that  great  difference  of  opinion  pre- 
vails on  this  point.  I  shall  in  the  first  place 
describe  the  arrangement  in  the  most  simple 
of  these  organs,  and  for  that  purpose  shall 
select  that  of  the  portio  major  of  the  fifth  pair. 
On  inspection  it  is  seen  that  the  large  coarse 
fibrils  of  the  nerve  on  approaching  the  ganglion 
begin  to  spread  out  from  each  other,  and  although 
in  its  interior  they  are,  as  we  have  already 
observed,  encrusted  by  the  grey  matter,  yet, 
on  scraping  this  away,  the  fibres  may  be  seen 
still  passing  on  uninterruptedly,  but  becoming 
more  and  more  separated  from  each  other. 
It  is  this  disposition  which  Scarpa  has  aptly 
enough  compared  to  a  rope  the  two  ends  of 
which  remain  twisted,  whilst  in  the  middle 
the  component  threads  are  unfolded  and  pulled 
asunder.  A  similar,  but  less  distinct  arrange- 
ment exists  in  the  spinal  ganglia. 

Although  the  continuity  of  the  fibres  through 
the  ganglion  is  easily  demonstrated,  yet  it 
would  be  wrong  to  conclude  that  this  passage 
is  all  that  happens ;  for  in  the  first  place  the 
three  branches  of  the  trigeminal  nerve  which 
emerge  from,  are  decidedly  larger  than  the 
trunk  of  the  same  nerve  which  passes  into 
the  ganglion.  Their  physical  qualities  are  also 
altered,  especially  as  relates  to  their  colour, 
which,  instead  of  having  the  whitish  aspect 
common  to  the  proper  fibres  of  the  cerebro- 
spinal axis,  is  for  some  distance  of  the  reddish 
hue  proper  to  the  ganglionic  system ;  and 
again  it  would  be  in  opposition  to  all  our 
notions  of  the  properties  of  the  grey  matter 

*  Rudiments  of  Physiol,  st.  ii.  a.  p.  87. 


to  imagine  that  the  fibres  do  not  maintain 
intimate  connexions  with  that  substance,  by 
which  means  its  influence,  whatever  it  may  be, 
is  communicated  to  those  threads. 

In  the  sympathetic  ganglions  the  internal 
formation  is  much  more  intricate  ;  and  it  is 
especially  in  reference  to  these  bodies  that  so 
much  diversity  of  opinion  prevails  among 
anatomists.  The  researches  of  Monro,*  Scarpa,f 
and  Lobstein,}  as  well  as  ocular  inspection, 
prove  that  some  fibres  undoubtedly  pass  without 
interruption  through  the  ganglion. 

On  making  a  section  of  the  first  cervical 
ganglion,  previously  hardened  by  alcohol, 
fibres  will  be  perceived,  which,  although  se- 
parated from  each  other  by  irregular  interstices 
filled  with  grey  matter,  are  still  continued 
uninterruptedly  from  one  to  the  other  ex- 
tremity. There  are,  however,  besides  these, 
other  fibres,  which  are  so  complex  that  it  is 
almost  impossible  to  demonstrate  their  exact 
disposition.  I  believe,  however,  that,  inde- 
pendently of  those  fibrils  which  run  through 
the  ganglion,  there  are  some  which  terminate 
in,  and  others  which  arise  from  the  grey  matter 
in  its  interior. 


Fig.  171. 


Superior  cervical  ganglion    of  the  great  intercostal 
nerve  of  the  right  side. 

a,  Trunk  of  the  great  intercostal  nerve  a  little 
below  the  foramen  caroticum.  b,  Trunk  of  the 
nerve  below  the  superior  cervical  ganglion. 
c,  c,  c,  c,  The  branches  which  from  the  three 
superior  cervico-spinal  nerves  run  to  join  the  su- 
perior cervical  ganglion  of  the  great  intercostal 
nerve,  d,  d,  d,  Nerves  issuing  from  the  superior 
cervical  ganglion,  e.  Nervous  fibriform  stratum  of 
the  ganglion,  f,  Reticulated  plexus  produced  by 
the  mingling  of  the  nervous  fibres,  g,  Reticulated 
or  plexiform  nervous  filaments.  h,  Nervous 
filaments  variously  mingled  with  others  connected 
with  the  neighbouring  cerebral  and  spinal  nerves, 
t,  The  nervous  filaments  of  which  the  trunk  of 
the  intercostal  nerve  below  the  superior  cervical 
ganglion  is  composed. 

*  Obs.  on  Nerv.  Sys.  p.  54. 

+  L.  c.  p.  14,  Tab.  1.  fig.  I,  2,3,  4. 

t  L.  c.  Tab.  tertia. 


GANGLION. 


375 


b.  What  is  the  nature  of  tlte  fibres  which 
are  connected  with  the  ganglia  ?  The  very 
interesting  inquiries  of  Brown,  Darwall,  Teale, 
Stanley,  and  others  into  the  nature  of  those 
frequent  affections  now  generally  known  under 
the  term  of  neuralgic  diseases,  by  which  a 
new  and  unexpected  light  has  been  thrown 
on  a  most  obscure  branch  of  pathology, 
render  this  part  of  the  present  investigation 
of  pre-eminent  importance.  The  mutual  in- 
fluence exerted  by  the  cerebro-spinal  axis 
and  the  great  sympathetic  on  each  other, 
in  consequence  of  which  disease  of  the  brain 
and  spinal  chord  may  cause  morbid  actions 
and  conditions  of  the  organs  of  digestion, 
circulation,  and  secretion,  and  vice  versa,  can 
only  be  experienced  by  a  reference  to  the 
relations  which  exist  between  these  two  great 
divisions  of  the  nervous  system.  Unfortu- 
nately, however,  this  question,  so  important 
both  as  regards  physiology  and  pathology,  is 
not  easily  resolved  on  account  of  the  difficulty 
in  the  present  state  of  our  knowledge  of  dis- 
tinguishing from  each  other  the  different  species 
of  fibres  which  enter  into  these  organs.  I 
shall  in  the  first  place  speak  of  the  fibres 
which  are  perceptible  to  the  naked  eye,  and 
afterwards  point  out  the  information  that  has 
been  afforded  by  microscopical  examination. 

The  intervertebral  ganglia  (and  these  ob- 
servations may  be  applied  to  those  of  the 
fifth  pair,  of  the  glosso-pharyngeal,  and  of 
the  pneumo-gastric)  receive  fibres  only  from 
the  posterior  roots  of  the  spinal  nerves,  which, 
since  the  researches  of  Bell,  Magendie,  and 
Mayo,  have  been  regarded  as  being  subordinate 
to  sensation.  But  if  the  important  principles 
announced  by  Dr.  M.  Hall  be  susceptible,  as 
I  believe  they  are,  of  that  confirmation  from 
anatomical  examination  of  which  at  present 
they  stand  in  need,  then  to  the  true  sensiferous 
fibrils  which  enter  these  ganglia  we  must  add 
what  are  called  by  Dr.  Hall  incident  filaments. 
It  is  also  a  question  which  yet  remains  to 
be  decided,  whether  the  twigs  that  are  known 
to  run  between  the  posterior  roots  of  the  spinal 
nerves  and  the  sympathetic  ganglions  pass  in 
reality  from  the  former  to  the  latter  or  from 
the  latter  to  the  former ;  if,  as  appears  most 
probable,  these  threads  are  furnished  by  the 
sympathetic,  then  it  is  to  be  presumed  they 
are  subsequently  continued  to  the  intervertebral 
ganglions. 

With  respect  to  the  sympathetic  ganglions, 
the  following  are  the  only  facts  that  are  at  this 
time  established. 

1.  There  are  longitudinal  commissural  fila- 
ments by  which  the  ganglia  are  joined  to  each 
other,  and  by  which  they  are  formed,  however 
remote  they  may  be  from  one  another,  into 
one  great  and  extensive  system. 

2.  There  are  fibrils  which  extend  between 
the  motiferous  part  of  the  cerebro-spinal  axis 
and  the  sympathetic,  but  whether  they  are 
derived  from  the  former  or  the  latter  is  not  de- 
cided. 

3.  There  are  sentient  fibrils  observing  a 
similar  disposition. 

As  the  anatomical  facts  by  which  these  facts 


are  established  will  be  found  under  the  head 
Sympathetic  Nerve,  only  a  few  remarks  are 
required  in  this  place. 

1.  With  respect  to  the  longitudinal  com- 
missural fibres,  they  are  as  necessary  here  as 
in  other  parts  of  the  nervous  system ;  and 
although  Bichat  speaks  of  this  connexion  of 
the  ganglions  being  occasionally  absent,  such 
deficiencies  are  extremely  rare,  and  if  they 
do  really  exist,  must  be  regarded  as  an  ab- 
normal state.  The  importance  of  this  con- 
nexion is  rendered  apparent  by  the  union  of 
the  several  nodules  placed  on  the  trunk  of  the 
sympathetic,  which  is  so  constant  that  anato- 
mists were  for  a  long  time  so  far  misled  by 
it  as  to  compare  tliis  gangliated  cord  with  the 
common  nerves  of  the  body ;  but  it  is  perhaps 
still  more  striking  in  the  commissural  fibres, 
which  are  so  invariably  noticed  passing  from 
the  sympathetic  to  the  small  ganglia  of  the 
head. 

2  and  3.  In  consequence  of  the  motor  and 
sentient  nerves  of  the  head  usually  forming 
distinct  trunks,  the  ophthalmic  ganglion  offers 
a  natural  analysis,  as  it  were,  of  the  connexion 
between  the  great  sympathetic  and  the  cerebro- 
spinal axis.  One  twig  passes  between  this 
small  body  and  the  nasal  nerve  of  the  fifth  pair 
(sentient);  a  second  extends  between  it  and 
the  lower  division  of  the  third  pair  (motor). 
The  dissections  of  Arnold  prove  that  a  similar 
connexion  exists  in  the  spheno-palatine,  the 
otic,  and  the  submaxillary  ganglia.*  Mayo 
has  also  ascertained  that  the  branches  placed 
between  the  ganglia  of  the  great  sympathetic 
and  the  compound  nerves  of  the  spine  are 
of  a  twofold  character,  one  set  being  attached 
to  the  sentient  and  the  other  to  the  motor  root. 
The  adjoining  figure  (7%.  172),  copied  from  a 
dissection  I  made  for  this  purpose,  shows  the 
mode  of  communication  in  the  thorax. 

Fig.  172. 


a,  Anterior  root.  c,  Ditto,  b,  Posterior  root 
entering  the  ganglion,    d,  Sympathetic  ganglion. 

e,  Filament  of   communication  to  posterior  root. 

f,  Filament  of  communication  to  anterior  root. 

*  These  connexions  are  very  beautifully  repre- 
sented in  his  work,  Icones  Nerv.  Capit.  Tab.  5,  6, 
7,  and  8.  On  some  points  relative  to  the  otic 
ganglion  it  has  been  proved  by  the  dissections  of 
Schlemm  that  Arnold  was  in  error,  especially  as 
relates  to  the  branch  supposed  to  be  furnished  from 
the  ganglion  to  the  tarsor  tympani. 


376 


GANGLION. 


Notwithstanding  so  many  important  points 
have  been  established,  it  must  be  confessed 
that  much  remains  to  be  decided.  Thus,  for 
example,  we  perceive  that  the  ganglion  of 
Meckel,  like  the  ganglions  of  the  sympathetic 
in  the  neck,  has  connected  with  it  a  motor 
fibril ;  but  this  fibril,  as  Arnold  has  observed, 
presents  the  whitish  character  and  firm  texture 
common  to  the  cerebro-spinal  nerves,  and 
therefore,  it  must  be  presumed,  passes  from 
the  portio  dura  to  the  ganglion,  whilst  the 
twigs  uniting  the  cervical  nerves  and  the 
sympathetic  are  reddish  and  soft,  rendering 
it  probable,  as  Fletcher  supposes,  that  they 
are  furnished  by  the  ganglia. 

Such  being  the  imperfect  results  of  ocular 
inspection,  we  are  naturally  anxious  to  obtain 
more  exact  information,  especially  in  reference 
to  the  character  of  the  different  orders  of  fibres 
which  are  connected  with  the  ganglia.  The 
microscopical  observations  which  are  being  car- 
ried on  at  this  time  with  so  much  zeal  in  Ger- 
many, and  from  the  prosecution  of  which  the 
most  valuable  evidence  may  be  anticipated 
respecting  the  undecided  points  of  minute 
anatomy,  have  already  thrown  some  light  on  this 
interesting  question.  Thus  Ehrenberg*  has  de- 
tected in  the  sympathetic  not  only  the  varicose 
fibres  which  some  imagine  are  proper  to  that 
system,  but  also  some  of  the  cylindrical  fibres  of 
which  the  cerebro-spinal  nerves  are  principally 
composed.  According  to  Lauth  and  Remark, 
the  nerves  of  organic  life  (i.  e.  of  the  sympa- 
thetic) consist  for  the  most  part  of  varicose 
fibres  mixed  up  with  a  small  proportion  of 
cylindrical ;  whilst  those  of  animal  life  consist 
principally  of  cylindrical  mingled  with  a  few 
varicose  fibres.  This  is  the  exact  appearance 
which  must  have  been  anticipated,  if  the  mu- 
tual interchange  of  fibres  described  by  Bichat,f 
W.  Philip,}  Mayo,§  Fletcher,||  and  others, 
really  exist. 

It  may  here  be  remarked  that  although  the 
accuracy  of  Ehrenberg's  researches,  confirmed 
as  they  have  been  by  Muller,  Purkinje,  Valen- 
tin and  others,  is  called  in  question  by  Krause, 
Berres,  and  Treviranus,  yet  the  essential  fact 
of  there  being  a  decided  difference  in  the  phy- 
sical character  of  different  orders  of  nervous 
fibres,  and,  consequently,  a  test  for  their  suc- 
cessful analysis,  is  universally  admitted.^! 

Lastly,  it  is  a  question  of  great  interest  whether 
there  are  not,  independently  of  the  relations 
which  exist  between  the  sympathetic  and  the 
cerebro-spinal  axis,  fibres  proper  to  the  former, 

*  h.  c.  p.  31. 

t  An.  Gen.  i.  p.  220.  "  The  ganglions  (of  the 
sympathetic)  like  the  brain  furnish  and  receive  their 
particular  nerves." 

i  On  Vital  Functions,  and  Gulstonian  Lect. 

«  Out.  of  Phy.  4th  edit.  p.  259. 

||  Rud.  of  Phy.  part  ii.  a.  p.  76. 

^  Since  the  above  was  written  I  have  learnt  that 
the  doubts  expressed  by  Treviranus,  Arnold,  and 
others,  as  to  the  correctness  of  the  views  of  Ehren- 
berg, have  been  confirmed.  Professor  Muller 
attributes  the  appearance  of  the  varicose  fibres  to 
artificial  causes ;  and  it  is  said  that  Ehrenberg 
himself  doubt3  if  such  fibres  exist  in;  th"e"  normal 
condition. 


which  establish  between  them  and  the  organs 
they  supply  with  nerves  most  important  con- 
nexions. Our  present  knowledge  does  not 
afford  the  means  of  solving  this  question ;  and, 
although  my  attention  has  been  particularly 
directed  to  this  subject,  still,  as  my  observa- 
tions are  as  yet  incomplete,  I  shall  satisfy 
myself  by  expressing  my  conviction  that  such 
a  system  of  nervous  fibres  does  exist. 

Covering. — Every  ganglion  possesses  two 
coverings:  the  outer  one  in  the  spinal  ganglions 
is  very  firm,  being  derived  from  the  vertebral 
dura  mater,  whilst  in  the  sympathetic  gan- 
glions it  is  composed  of  condensed  cellular 
tissue.  On  raising  very  carefully  the  external 
capsule,  a  more  delicate  tunic  is  exposed, 
which  adheres  to  the  proper  ganglionic  tissue. 

Bloodvessels.— These  bodies,  like  all  other 
parts  of  the  nervous  system,  are  amply  sup- 
plied with  arterial  blood.  After  a  successful 
injection,  two,  three,  or  more  arteries,  derived 
from  the  neighbouring  vessels,  may  be  readily 
observed  running  to  the  ganglion.  Each  vessel, 
having  perforated  the  coverings  of  the  ganglion, 
forms  according  to  Wutzer  a  plexus  on  the  inner 
surface  of  the  capsule,  and  at  length  sends  de- 
licate branches  into  the  pulpy  matter,  which, 
with  the  aid  of  the  microscope,  may  be  ob- 
served to  run  in  the  same  direction  with  the 
nervous  filaments.  (See  figs.  171, 172.)  The 
exact  mode  in  which  these  vessels  terminate  is 
unknown,  but  it  is  probable,  as  in  the  cerebro- 
spinal system,  that  each  nervous  fibre  is  ac- 
companied by  a  minute  artery  and  vein.  No 
lymphatics  have  been  demonstrated,  but  ana- 
logy tends  to  prove  their  existence,  and  Lob- 
stein  states  that  he  has  often  seen  them  forming 
networks  around  the  ganglions. 

Chemical  composition. — The  experiments 
performed  by  Bichat*  and  Wutzerf  would  tend 
to  show  that  the  substance  of  the  ganglions  is 
distinct  in  its  qualities  from  the  cerebral  matter 
and  also  from  that  of  the  nerves.  By  boiling,  it 
is  at  first  hardened,  but  soon  becomes  softened  ; 
maceration  in  cold  water  renders  it  more  soft 
and  pulpy,  and  if  sufficiently  prolonged,  the 
water  being  frequently  changed,  it  is  converted 
into  adipocire.  It  is  liquefied  by  the  alkalies, 
and  is  rendered  crisp  and  hard  by  the  acids 
and  alcohol. 

Bibliography.  —  Haase,  De  gangliis  nervor. 
Scarpa,  Anat.  Annot.  Liber  i.  de  nerv.  gang,  et 
plexibus.  Monro,  Obs.  on  nerv.  system.  Soem- 
mering, De  corp.  hum.  fabric,  t.  iv.  Bichat,  Anat. 
gen.  Wutzer,  De  corp.  hum.  ganglior.  fabrica 
atque  usu.  This  work  contains  an  elaborate  list 
of  the  various  authors  who  have  treated  of  the 
ganglions,  and  an  epitome  of  their  opinions. 
Lobstein,  De  nervi  sympath.  humani,  fabrica,  usu 
et  morbis.  F.  Arnold,  Kopfthiel  des  Vegetativen 
nervensystem,  beim  Menschen.  J.  Muller,  Hand-- 
buch  der  Physiol,  des  Menschen,  1834.  C.  J.  Eh- 
renberg, Structur  des  Seelenorgans  bei  Menschen 
und  Thieren,  Berlin,  1836 ;  Anat.  der  Microsko- 
pischen  Gebilde  der  Menschlichen  Kbrpers.  Wien. 
1836. 

C R.  D.  Grainger.) 
*  Anat.  Gen.  t.  i.  p.  226. 

+  De  Corp.  Hum.  Gang.  Fabrica  atque  Usu, 
§  55.  The  reader  will  find  in  this  work  many  de- 
tails relative  to  the  above  subject. 


GASTEROPODA. 


377 


GASTEROPODA,  (yeumf,  venter,  nov<;, 
pes;  Eng.  Gasteropods ;  Fr.  Gasteropodes ; 
Germ.  Buuchf'usser ;  Mollusca  Rcpentia, 
Poli.) 

Definition. — An  extensive  class  of  the  Mol- 
luscous division  of  the  animal  kingdom  dis- 
tinguished by  the  structure  and  position  of  their 
locomotive  apparatus,  which  consists  of  a  mus- 
cular disc  attached  to  the  ventral  surface  of  the 
body,  serving  either  as  an  instrument  by  means 
of  which  the  animal  can  crawl,  or  in  rarer 
instances  compressed  into  a  muscular  mem- 
brane useful  in  swimming. 

Characters  of  the  class. —  Body  soft,  enclosed 
in  a  muscular  covering,  which,  from  its  contrac- 
tility in  every  direction,  produces  great  variety 
in  the  external  form  of  the  animal  :  the  back  is 
covered  with  a  mantle  of  greater  or  less  extent, 
which  in  most  of  the  geneia  secretes  a  shell 
either  enclosed  within  its  substance,  or,  as  is 
more  frequently  the  case,  external  and  suffi- 
ciently large  to  conceal  and  protect  the  whole 
body,  in  which  case  it  is  often  provided  with 
an  operculum  capable  of  closing  its  orifice 
when  the  animal  is  lodged  within  it.  The  head 
is  anterior,  distinct,  and  generally  furnished 
with  two,  four,  or  six  tentacles,  which  are 
placed  above  the  oral  aperture,  and  merely 
serve  as  instruments  of  touch.  The  eyes  are 
two  in  number,  and  are  placed  sometimes  on 
the  head  itself,  but  more  generally  at  the  base, 
at  the  side  or  at  the  extremity  of  the  tentacles ; 
they  are  always  very  small,  and  not  unfre- 
quently  wanting.  The  muscular  disc  which  is 
subservient  to  locomotion  is  called  the  foot, 
and  is  generally  broad  and  fleshy,  forming  a 
powerful  sucker,  bnt  in  some  instances  it  takes 
the  shape  of  a  deep  furrow,  or  is  compressed 
into  a  vertical  lamella.  The  respiratory  appa- 
ratus varies  in  structure ;  in  some  genera  it  is 
composed  of  vascular  ramifications  which  line 
a  cavity  into  which  the  respired  medium  is 
freely  admitted.  Others  are  provided  with 
branchiae,  adapted  to  the  respiration  of  water, 
variously  disposed  upon  the  exterior  of  the 
body,  or  concealed  internally.  The  heart 
generally  consists  of  an  auricle  and  ventricle, 
and  is  systemic,  or,  in  other  words,  receives 
the  blood  from  the  organs  of  respiration,  and 
propels  it  through  the  body.  The  seiuul 
organs  vary  in  their  structure  in  different 
orders  ;  in  the  greater  number  each  individual 
is  possessed  both  of  an  ovigerous  and  impreg- 
nating apparatus,  but  copulation  is  essentia!  to 
fecundity:  in  many  the  sexes  are  distinct, 
and  some  are  hermaphrodite  and  self-impreg- 
nating. Some  species  are  terrestrial  and  others 
aquatic. 

In  separating  the  Gasteropoda  into  orders,  the 
naturalist  finds  in  the  position  and  structure 
of  the  branchial  apparatus  a  character  suffi- 
ciently obvious ;  and  as  the  arrangement  of 
these  organs  is  modified  by  the  circumstances 
of  each  individual,  and  is  generally  in  relation 
with  the  peculiarities  met  with  in  the  internal 
organization  of  the  animal,  the  branchiae  are  at 
present  universally  referred  to  as  affording  a 
convenient  basis  of  classification.  We  shall 
in  this  article  follow  the  arrangement  adopted 

VOL.  II. 


by  Ferussac,  of  which,  as  well  as  of  the 
systems  of  other  zoologists,  an  outline  is  con- 
tained in  the  following  table. 

Order  I.  NUDIBRANCHIATA*  (Cuv.) 

Syn.  Polybranchiata,-f  and  genus  Doris, 
Blainville  ;  Gasteropodes  Dermobranchcs,X  Du- 
meril ;  Gasteropodes  Tritoniens,  Lamarck. 

In  these  the  branchiae  are  symmetrical,  as- 
suming a  variety  of  forms,  but  always  placed 
upon  some  part  of  the  back,  where  they  are 
unprotected  by  any  covering  ;  the  animals  may 
be  provided  with  a  shell  or  naked,  but  they 
are  all  hermaphrodite  with  mutual  copulation, 
and  marine. 

1st  Sub-order,   Anthobranchiata,\  Goldfuss; 
Cyclobranchiata,\\  Blainville. 

1st  Fam.  Doris. 
2d  Sub-order,  Polybranchiata,  Blainville. 

2d  Fam.  Tritonia,  fig.  173. 

3d  Fam.  Glaucus,  fig.  174. 


Fig.  173. 


Order  II.  INFE  ROBRANC  HI  A  TA , 
(Cuv.  and  Blain.) 

Syn.  Gast.  Dermobranches,  Dumeril;  Gasi. 
Fhyllidkns,  Lamarck. 

In  the  Inferobranchiate  Gasteropods  the 
branchiae  are  arranged  under  the  inferior  border 
of  the  mantle  on  both  sides  of  the  body,  or 
upon  one  side  only  :  the  mantle  sometimes 
contains  a  calcareous  lamella.    All  the  genera 

*  Nudns,  naked  •,  branchiae,  gills, 
t  IToXuf ,  maruj  ;  branchiae. 
X  Aep/ua,  shin. 
§  Av0o;,  a  flower. 
||  Kux'htx;,  a  circle. 

2  c 


378 


GASTEROPODA. 


are  hermaphrodite  with  reciprocal  impregnation, 
and  marine. 

1st  Sub-order,  Phyllidiadce,  Cuv. 

1st  Fam.  Phyllidia,  Jig.  175. 
2d  Sub-order,  Semi-phyllidiada,  Lam. 

2d  Fam.  Gastroplax,  Blainville. 

3d  Fam.  Pieurobranchus,  Cuv. 


Fig.  175. 


Order  III.  TECTIBRANCHIATA* 

(Cuv.) 

Syn.  Chismobnmches,  Blainville;  Gust. 
Adelobranches,-\  Dumeril;  Gast.  P/iyllidiens 
and  Laplysiens,  Lamarck. 

In  tins  order  the  branchia?  are  placed  upon 
the  dorsal  aspect  of  the  body,  but  are  pro- 
tected by  a  fold  of  the  mantle  which  almost 
always  contains  a  shell  presenting  a  rudimen- 
tary spire.  They  are  all  hermaphrodite  like 
the  preceding,  and  marine. 

1st  Fam.  Dikera. 

2d  Fam.  Altera. 

Order  IV.  PULMONALIA  INOPER- 
CULATA,  (Ferussac  ) 

Syn.  Pulmones,  Cuv.;  J  Pulmobr  (inches, 
Blainville;  Gast.  Trac/ielipodes,§  Lamarck. 

The  respiratory  apparatus  is  here  adapted  to 
the  respiration  of  atmospheric  air,  and  instead 
of  being  composed  of  branchial  tufts  or  la- 
minae, consists  of  a  cavity  lined  by  the  rami- 
fications of  the  pulmonary  vessels,  the  entrance 
to  which  can  be  opened  or  closed  at  the  plea- 
sure of  the  animal.  Almost  all  the  species 
are  provided  with  a  shell  either  turbinated  or 
concealed  within  the  mantle,  but  are  never 
furnished  with  a  calcareous  operculum.  Every 

*  Tectus,  covered, 
f  A$r,Xo;,  concealed. 
|  Pulmo,  lungs. 

§  Tpap^nXof,  tlie  neck  ;  nov;,  foot. 


individual  is  hermaphrodite,  but  mutual  copu- 
lation is  essential  to  fertility.  Some  are  terres- 
trial, others  inhabit  fresh  water,  and  some  are 
marine. 

1st  Sub-order,  Geophilida,*  Ferussac. 

1st  Fam.  Limax. 

2d  Fam.  Helix. 
2d  Sub-order,  Gehydrophilida,\  Ferussac. 

3d  Fam.  Auricula. 
3d  Sub-order,  Hygrophilida?,l  Ferussac. 

4th  Fam.  Limneeus. 

Order  V.  PULMONALIA  OPERCU- 
LATA,  (Ferussac.) 

Syn.  Pectinibranchiatajj  Cuv. ;  Siphoni- 
branchiata,\\  Blain. 

The  respiratory  organs  of  the  animals  form- 
ing this  order  are  similar  in  structure  to  those 
found  in  the  last,  but  they  differ  materially  in 
other  points.  In  all  the  operculated  division 
the  shell  is  closed  by  a  calcareous  operculum 
not  found  in  the  last,  and  instead  of  that 
hermaphrodite  condition  of  the  sexual  organs 
common  to  the  inoperculated  order,  the  sexes 
are  distinct,  the  male  and  female  parts  existing 
in  different  individuals.  They  are  all  terres- 
trial. 

1st  Fam.  Helicina. 
2d  Fam.  Turbicina. 

Order  VI.   PEC  TIN1  BRA  NC  HI  A  TA, 
(Cuv.) 

Syn.  Trachelipodes,  Lamarck  ;  Monopleuri- 
brunches,  Blain. ;  Gast.  Adelobranches  and 
Siphonibranches,  Dumeril. 

This  extensive  order,  which  comprises  most 
of  the  univalve  mollusks  whose  shells  enrich 
our  cabinets,  is  characterized  by  a  respira- 
tory apparatus  adapted  to  an  aquatic  medium. 
The  branchise  are  pectinated,  consisting  of 
ranges  of  fringes  disposed  like  the  teeth  of  a 
comb,  and  generally  enclosed  in  a  dorsal  cavity 
which  opens  externally  at  the  side  of  the  body 
or  above  the  head.  The  shell  is  always  turbi- 
nated, and  sometimes  provided  with  an  oper- 
culum. The  sexes  are  separate,  and  the  ani- 
mals fluviatile  or  marine. 

1st  Sub-order,  Pomastomidaft  Ferussac ;  Chis- 
mobranches,  Blainville. 

1st  Fam.  Turbo,  Lin. 

2d  Fam.  Trochus,  Lin. 
2d  Sub-order,  Hemipomastomidte,  Ferussac. 

3d  Fam.  Cerithium,  Adanson. 

4th  Fam.  Buccinum,  Lin. 

5th  Fam.  Murex,  Lin. 

6th  Fam.  Strombus,  Lin. 

7th  Fam.  Conns,  Lin. 
3d  Sub-order,  Apomastomida,  Ferussac. 

8th  Fam. 

9th  Fam.  Volutu,  Lin. 
10th  Fam. 
4th  Sub-order,  Adelodermida,  Ferussac. 
11th  Fam.  Sigarelus,  Adanson. 

*  r»,  the  earth  ;  $ iXem,  to  love. 

f  Vn,  the  earth ;  v$a>p,  the  water  ;  <J>iX£ft>. 

$  Typt;,  moist ;  <J>iAe«. 

§  Pecten,  -inis,  a  comb. 

||  2icfa)v,  a  canal. 

%  Ua>jA.a,  operculum;  <rroy.a,  mouth. 


GASTEROPODA. 


379 


Order  VII.  SCUTIBRANC  HI  A  TA* 

(Cuv.) 

Syn.  Cervicobranches,  Blain. ;  Chismo- 
branches,  Blain. ;  Gast.  Dermobranches,  Dum.; 
G.  Trachelipodes,  Lam. 

Fig.  176. 


In  this  order  the  structure  of  the  branchiae 
is  analogous  to  what  has  been  described  in  the 
Pectinibranchiata ;  but  the  shell,  which  in  the 
latter  was  always  turbinated,  in  the  Scutibran- 
chiata  is  a  mere  shield,  in  which  the  indications 
of  a  spire  are  very  slight  or  totally  deficient. 
There  is  never  an  operculum.  The  organs  of 
both  sexes  are  united  in  every  individual,  but 
there  is  no  necessity  for  copulation,  each  ani- 
mal being  self-impregnating.  The  species  are 
all  aquatic. 

1st  Sub-order,  Anthophora.f 

1st  Farn.  Haliotis,  Jig.  176. 
2d  Sub-order,  Calyptracidte,\  Lam. 

*  Scutum,  a  shield. 

t  Avfloj,  a  flower ;  <f>epai,  to  carry. 

t  KaTiWTpa,  a  covering. 


2d  Fam.  Capulus* 
3d  Sub-order,   Heteropodaf  Nucleobranches, 
Blainville. 
3d  Fam.  Pterotrachea,  Jig.  177. 

Order  VIII.  CYCLOBRANCHIATA, 
(Cuv.) 

Syn.  Dermobranches,  Dum.;  Gast.  Phylli- 
diens,  Lam. ;  Gast.  Chismobi-anches,  Blain. 

In  this  order  the  branchia;  are  arranged 
under  the  margin  of  the  mantle  around  the 
circumference  of  the  body ;  the  shell  is  a 
simple  shield,  either  composed  of  one  piece, 
which  is  never  turbinated,  or  else  made  up  of 
several  divisions.  They  are  all  hermaphrodite 
and  self-impregnating. 

1st  Sub-order,  Chismobranchiata,  Blain. ;  Cy- 
clobranchiata,  Goldfuss. 

1st  Fam.  Patella. 
2d  Sub-order,  Pulyplaxiphora,\  Blain. 

2d  Fam.  Oscabrion. 

Cuvier  detaches  the  genera  Vermetus,  Magi- 
lus,  and  Siliquaria  from  the  Pectinibranchiata 
on  account  of  the  irregular  form  of  their  shell, 
which  is  only  spiral  at  its  commencement,  and 
is  usually  firmly  attached  to  some  foreign  body, 
a  circumstance  which  involves  as  a  necessary 
consequence  the  hermaphrodite  type  of  the 
sexual  organs,  so  that  these  genera  are  self- 
impregnating.  He  has,  therefore,  arranged 
them  in  a  separate  order,  to  which  he  applies 
the  name  of  Tubulibranckiata, 

Tegumentary  system. — The  skin  which  in- 
vests the  Gasteropoda  varies  exceedingly  in 
texture,  not  only  in  different  species  but  in  dif- 
ferent pares  of  the  same  animal ;  its  structure 
being  modified  by  a  variety  of  circumstances 
connected  with  the  habits  of  the  creature,  the 
presence  or  absence  of  a  calcareous  covering,  or 
the  mode  of  respiration.  In  the  naked  Gaste- 
ropods,  especially  in  the  terrestrial  species,  it  is 
thick  and  rugose,  serving  as  a  protection  against 
the  vicissitudes  consequent  upon  the  changeable 
medium  which  they  inhabit.  In  such  as  are 
aquatic  the  integument  is  proportionably  thin- 
ner, and  its  surface  more  smooth  and  even ;  in 
both,  however,  it  differs  much  in  texture  in  dif- 
ferent parts  of  the  body ;  thus  in  the  dermo- 
branchiate  species  it  becomes  attenuated  into  a 
thin  film,  where  it  invests  the  vascular  appen- 
dages subservient  to  respiration,  and  such  por- 
tions as  cover  the  organs  of  sense  assume  a 
transparency  and  delicacy  adapted  to  the  sen- 
sibility of  the  parts  beneath.  In  those  orders 
which  are  provided  with  shells,  the  integument 
which  protects  such  parts  of  the  body  as  are 
exposed  when  the  animal  partially  emerges 
from  its  abode,  is  thick  and  spongy,  and  very 
different  from  the  thin  fibrous  membrane  which 
invests  the  mass  of  viscera  contained  within 
the  shell.  We  are  led  by  various  circum- 
stances to  presume  that  the  skin  of  all  the 
Gasteropods  is  in  structure  essentially  ana- 
logous to  that  of  higher  animals,  and  in  de- 

*  Many  of  the  CapuloiJ  Gasteropods  are  thought 
by  Cuvier  to  be  dioecious. 

f  E-ripoc,  different ;  Ttovt,  foot. 

t  rioXuf,  many;  ir'Ka^,  a  scale ;  <fip«,  to  carry. 

2  c  2 


380 


GASTEROPODA. 


scribing  it  we  shall  avoid  obscurity  by  applying 
to  its  different  parts  the  names  ordinarily  made 
use  of  by  anatomists  to  distinguish  the  tissues 
enumerated  as  composing  the  human  integu- 
ment. 

The  dermis  is  an  extremely  lax  and  cellular 
texture,  eminently  elastic,  and  so  intimately 
blended  with  the  contractile  layers  beneath  it, 
that  it  is  difficult  to  recognise  it  as  a  distinct 
structure  :  its  great  peculiarity  consists  in  the 
power  which  it  possesses  of  secreting  calcareous 
matter,  which  being  deposited  either  in  a  cavity 
within  its  substance,  or  as  is  more  frequently 
the  case,  upon  its  outer  surface,  forms  a  con- 
cealed or  external  shell :  from  this  circum- 
stance, and  from  the  abundant  quantity  of 
mucus  which  it  constantly  furnishes,  we  may 
infer  its  great  vascularity,  while  the  high  degree 
of  sensibility  which  it  evidently  possesses  une- 
quivocally demonstrates  that  it  is  plentifully 
supplied  with  nerves,  although  the  existence  of 
a  true  papillary  structure  cannot  be  satisfac- 
torily distinguished.  The  colouring  pigment 
likewise  exists,  as  is  evident  from  the  brilliant 
markings  which  are  often  met  with  in  some  of 
the  more  highly  coloured  species ;  but  there  is 
a  circumstance  in  connection  with  this  rete 
mucosum  which  requires  particular  mention,  as 
it  will  enable  us  afterwards  more  clearly  to  ex- 
plain the  formation  of  shells ;  the  pigment  is 
not  merely  a  layer  which  serves  to  paint  the 
surface  of  the  body  generally,  but  appears  ra- 
ther to  be  an  infiltration  of  the  lax  tissue  of  the 
cutis  with  coloured  fluid,  which  is  poured  out 
in  great  abundance  at  particular  points,  espe- 
cially around  the  margin  of  the  shell,  and  there 
being  mixed  up  with  the  calcareous  matter  se- 
creted by  the  collar,  its  tints  are  transferred  to 
the  exterior  of  the  shell  itself,  tinging  it  with 
similar  hues.  The  epidermis  is  evidently  defi- 
cient, its  place  being  supplied  by  the  viscid 
matter  with  which  the  surface  of  the  body  is 
continually  lubricated.  The  muciparous  crypts 
destined  to  furnish  the  copious  supply  of  glairy 
fluid  with  which  the  skin  is  so  largely  moist- 
ened, have  not  been  detected,  but  the  pores 
through  which  it  exudes  are  sufficiently  distinct. 
It  is  in  connexion  with  the  needful  diffusion  of 
this  secretion  over  the  entire  animal,  that  the 
skin  of  the  terrestrial  species,  as  the  Slugs  and 
Snails,  is  observed  to  be  deeply  furrowed  by 
larg€  anastomosing  channels,  formed  by  the 
rugae  of  the  surface,  and  serving  as  canals  for 
its  conveyance  by  a  species  of  irrigation  to 
every  point.  No  pilous  system,  properly  so 
called,  exists  in  any  of  the  Gasteropods,  the 
hairy  covering  of  many  shells  being,  as  we  shall 
presently  see,  of  a  widely  different  nature. 

From  the  modifications  observable  in  the 
structure  of  the  integument,  it  is  not  to  be  won- 
dered at  that  names  have  been  applied  to  diffe- 
rent portions,  which  it  will  be  useful  to  notice, 
especially  as  they  are  not  unfrequently  used  in 
a  confused  and  unprecise  manner.  That  por- 
tion of  the  skin  which  is  more  immediately 
connected  with  the  secretion  of  the  shell,  in 
such  Gasteropoda  as  are  provided  with  a  de- 
fence of  that  description,  has  been  termed  the 
mantle,  and  in  certain  instances,  from  the  mode 


in  which  it  seems  to  form  a  special  coering  to 
a  part  of  the  body,  it  has  some  claim  to  the 
name ;  the  mantle  is,  however,  extremely  varia 
ble,  both  in  position  and  arrangement.  In  the 
Nudibranchiata,  which  have  no  shell,  it  cannot 
be  said  to  exist,  as  no  fold  of  the  integument  or 
defined  margin  indicating  a  portion  deserving 
of  a  distinct  appellation  can  be  detected.  In 
the  Tectibranchiata  the  mantle  is  a  small  trian- 
gular fold  of  the  integument  on  the  right  side  of 
the  body,  inclosing  a  rudimentary  shell,  and 
serving  as  a  covering  to  the  subjacent  branchiae. 
In  the  Inferobranchiata  it  invests  the  whole  of 
the  back,  and  forms  a  fold  around  the  margins 
of  the  body,  beneath  which  the  branchiae  are 
found  ;  whilst  in  all  the  conchiferous  Gastero- 
pods it  lines  the  interior  of  the  shell,  whatever 
its  shape,  forming  a  distinct  fold  or  thickened 
rim  around  its  aperture,  to  which  when  much 
developed,  as  in  Helix,  the  name  of  collar  is 
not  improperly  applied. 

In  the  naked  terrestrial  species  the  mantle 
consists  of  a  thickened  portion,  occupying  a 
variable  position  on  the  back,  and  more  or  less 
defined  by  a  distinct  margin ;  it  is  here  not  un- 
frequently termed  the  corselet,  and  generally 
contains  a  calcareous  plate.  In  Vaginula  it 
covers  the  whole  of  the  back ;  in  Umax  it  occu- 
pies only  its  anterior  portion ;  in  Parmacella  it 
is  found  in  the  middle  of  the  dorsal  region, 
whilst  in  Testacella  it  is  placed  quite  poste- 
riorly in  the  vicinity  of  the  tail ;  yet  whatever  its 
situation,  shape,  or  size,  it  is  the  immediate 
agent  in  the  formation  of  the  shell,  and  as  such 
we  have  deemed  it  necessary  to  be  thus  precise 
in  describing  the  different  aspects  which  it 
assumes. 

Growth  of  shell. — The  varied  and  beautiful 
shells  that  form  so  important  a  part  of  the  inte- 
gument of  many  individuals  belonging  to  this 
order,  however  they  may  differ  in  external  form 
and  apparent  complication,  are  essentially  simi- 
lar in  composition  and  in  the  manner  of  their 
growth.  These  calcareous  defences,  although 
serving  in  many  cases  as  a  support  to  the  ani- 
mal, from  which  important  muscles  take  their 
origin,  differ  widely  from  the  internal  skeletons 
of  vertebrate  animals,  being  mere  excretions 
from  the  surface  of  the  body,  absolutely  extra- 
vital  and  extra-vascular,  their  growth  being  en- 
tirely carried  on  by  the  addition  of  calcareous 
particles  deposited  in  consecutive  layers.  The 
dermis  or  vascular  portion  of  the  integument  is 
the  secreting  organ  which  furnishes  the  earthy 
matter,  pouring  it  out  apparently  from  any  part 
of  the  surface  of  the  body,  although  the  thicker 
portion,  distinguished  by  the  appellation  of  the 
mantle,  is  more  especially  adapted  to  its  pro- 
duction. The  calcareous  matter  is  never  depo- 
sited in  the  areolae  of  the  dermis  itself,  but  ex- 
udes from  the  surface,  suspended  in  the  mucus 
which  is  so  copiously  poured  out  from  the  mu- 
ciparous pores,  and  gradually  hardening  by  ex- 
posure; this  calciferous  fluid  forms  a  layer  of 
shell,  coating  the  inner  surface  of  the  pre-exist- 
ent  layers  to  increase  the  size  of  the  original 
shell,  or  else  is  furnished  at  particular  points 
for  the  reparation  of  injuries  which  accident 
may  have  occasioned.    It  is  to  the  investiga- 


GASTEROPODA. 


381 


tions  of  Reaumur  that  we  are  indebted  for  our 
knowledge  concerning  this  interesting  process, 
and  subsequent  writers  have  added  little  to  the 
information  derived  from  his  researches;  in 
order,  however,  to  lay  before  the  reader  the 
principal  facts  connected  with  this  subject,  we 
shall  commence  with  the  simplest  forms  of  the 
process,  and  gradually  advance  towards  such  as 
are  more  complicated  and  less  easily  under- 
stood. 

The  shells  of  the  Gasteropoda  are  of  two 
kinds,  some  being  entirely  concealed  within 
the  substance  of  the  mantle,  and  consequently 
internal,  whilst  others  are  placed  upon  the  sur- 
face of  the  body  external  to  the  soft  integument. 
In  the  former  case  the  shell  is  uniform  in  tex- 
ture and  colourless  ;  in  the  latter,  its  develope- 
ment  is  much  more  elaborate,  and  it  is  not  un- 
frequently  moulded  into  a  great  diversity  of 
forms,  and  painted  with  various  tints,  which  are 
sometimes  of  great  brilliancy.  The  internal  or 
dermic  shells  are  found  in  many  of  the  pulmo- 
nary and  tectibranchiate  orders,  and  possess 
but  little  solidity ;  although  inclosed  in  the 
substance  of  the  mantle,  they  are  so  little  adhe- 
rent, that  when  exposed  by  an  incision  they 
readily  fall  out  of  the  cavity  in  which  they  are 
lodged,  and  from  which  they  are  apparently 
quite  detached.  Their  substance  is  generally 
calcareous,  but  in  many  instances,  as  in  Aplysia, 
the  shell  is  of  a  horny  texture,  being  transpa- 
rent, flexible,  and  elastic,  as  is  the  gladius  of 
many  of  the  Cephalopod  Mollusca.  In  all 
cases  horny  or  calcareous  plates  of  this  descrip- 
tion are  found  to  be  composed  of  superposed 
lamella,  which  are  successively  secreted  by  the 
floor  of  the  cavity  in  which  they  are  contained, 
the  inferior  layer  being  always  the  largest  and 
most  recent.  These  shells,  therefore,  may  be  con- 
sidered as  merely  formed  by  the  deposition  of 
successive  coats  of  varnish,  which  become  indu- 
rated, and  the  simple  manner  of  their  growth  will 
best  exemplify  the  mode  in  which  more  compli- 
cated shells,  whatever  be  their  form,  are  con- 
structed. External  shells  present  an  endless  di- 
versity of  figure,  and  some  classification  of  their 
principal  forms  will  facilitate  our  contemplation 
of  the  peculiarity  observable  in  each.  The  con- 
cealed shells,  which  are  merely  the  rudiments  of 
what  we  are  now  considering,  are  so  small  in  com- 
parison with  the  size  of  the  body,  that  they  can 
only  be  looked  upon  as  serving  for  the  protec- 
tion of  the  more  important  organs,  namely,  the 
heartand  respiratory  apparatus,  which  are  placed 
beneath  them,  but  the  external  shells,  from 
their  great  developement,  are  not  merely  a  partial 
protection  to  the  animal,  but  in  most  cases 
constitute  an  abode  into  which  the  creature 
can  retract  its  whole  body.  The  external  shell 
consists  generally  of  one  piece,  the  form  of 
which  may  be  symmetrical,  in  which  case  it  is 
a  cone  or  disc  simply  covering  the  back  of  the 
animal ;  or,  as  is  generally  the  case,  the  shell 
may  be  more  or  less  twisted  around  a  central 
axis,  forming  a  convoluted,  turbinated,  or  spiri- 
valve  shell.  In  one  genus  only,  Chiton,  Lin., 
the  shell  is  formed  of  several  pieces  articulated 
with  each  other,  and  covering  the  surface  of  the 
back. 


The  shell  of  the  Patella,  a  section  of  which 
is  represented  in  jig.  178,  is  a  simple  conep'aeed 
upon  the  back  of  the  creature,  which  it  com- 
pletely covers,  and  upon  which  it  is  evidently 
moulded.  On  making  a  section  of  the  animal, 
as  in  the  figure,  the  shell  is  found  to  be  entirely 
lined  by  the  mantle  a,  b,  by  which  it  is  secreted. 

Fig.  178. 


That  the  whole  surface  of  the  mantle  is  capable 
of  secreting  the  calcifying  fluid  from  which  the 
shell  is  formed,  is  distinctly  proved  by  the 
manner  in  which  a  fracture  or  perforation  in 
any  part  is  speedily  repaired  by  the  deposition 
of  a  patch  of  calcareous  matter  beneath  it,  but 
in  the  ordinary  growth  of  the  animal  the  differ- 
ent portions  of  the  mantle  execute  different 
functions.    It  is  obvious  that  the  enlargement 
of  the  body  of  the  patella,  as  its  age  increases, 
must  necessitate  a  corresponding  enlargement 
of  its  habitation,  and  this  is  principally  effected 
by  additions  of  calcareous  matter  in  succes- 
sively larger  rings  around  the  mouth  of  the 
shell  only  ;  the  great  agent  therefore  in  forming 
the  shell  is  the  margin  of  the  mantle,  b,  b.  This 
hangs  loosely  as  a  fringe  near  the  mouth  of  the 
shell,  and  being  moveable  at  the  will  of  the 
animal,  the  calcareous  matter  which  it  pre- 
eminently furnishes  may  be  laid  on  in  succes- 
sive layers  to  extend  the  mouth  of  its  abode  ; 
and  these  consecutive  additions  are  indicated 
externally  by  concentric  lines  running  parallel 
with  the  circumference  of  the  shell,  the  num- 
ber of  which  necessarily  increases  with  age. 
Whilst  the  abode  of  the  creature  is  thus  en- 
larged by  the  deposition  of  shell  from  the  vas- 
cular and  spongy  margins  of  the  mantle,  the 
office  of  the  rest  of  that  membrane  is  reduced  to 
the  increase  of  its  thickness,  depositing  succes- 
sive coatings  of  calcareous  particles,  which  are 
laid  on  to  its  inner  surface,  and  when  a  section 
of  the  shell  is  made  (fj,  these  last-formed  strata 
are  readily  distinguishable  by  their  whiteness 
and  different  arrangement.    So  far  the  produc- 
tion of  an  external  shell  is  entirely  similar  to 
what  we  have  met  with  in  the  formation  of  the 
internal  defences  of  the  naked  Gasteropoda,  yet 
in  other  respects  the  former  are  much  more  ela- 
borately organised.    In  the  first  place  many  of 
them  are  adorned  externally  with  colours,  not 
unfrequently  arranged  with  great  regularity  and 
beauty  ;  these  tints  belong  exclusively  to  the 
outer  layers  of  the  shell,  that  is,  to  those  formed 
by  the  margins  of  the  mantle,  and  are  produced 
by  a  glandular  structure  appropriated  to  the 
secretion  of  the  colouring  matter,  which  only 
exists  in  the  vascular  circumference  of  the  cab. 


382 


GASTEROPODA. 


ciferous  membrane.  The  colouring  matter 
becomes  thus  incorporated  at  definite  points, 
with  the  cement  by  which  the  shell  is  extended, 
and  is  arranged  in  various  manners  according 
to  the  position  of  the  secreting  organs  which 
furnish  it.  Another  peculiarity  which  distin- 
guishes external  shells  is  that  their  outer  sur- 
face is  often  invested  with  a  membranous  layer, 
called  the  epidermis,  which  having  been  re- 
garded by  some  authors  as  a  part  of  the  true 
integument  of  the  body,  has  given  rise  to  the 
supposition  that  all  shells  being  placed  between 
two  layers  of  the  skin  were  in  fact  internal,  the 
difference  between  the  one  and  the  other  con- 
sisting merely  in  the  extent  of  development. 
In  support  of  this  opinion  reference  has  been 
made  to  the  great  thickness  of  this  epidermic 
coat,  which  not  unfrequently  is  such  as  to  give 
to  the  surface  of  the  shell  a  felted  or  pilous  ap- 
pearance ;  but  if  such  an  idea  were  correct,  it 
is  evident  that  the  epidermis  must  be  formed 
prior  to  the  deposit  of  calcareous  matter  be- 
neath it,  which  observation  has  disproved,  in- 
asmuch as  those  shells  in  which  the  epidermic 
covering  is  most  dense  and  shaggy  are  found 
whilst  in  ovo  to  be  without  such  an  investment. 
The  so-called  epidermis,  therefore,  whatever 
may  be  the  aspect  which  it  presents,  whether  it 
be,  as  is  usually  the  case,  a  brittle  lamella  en- 
crusting the  shell,  or  a  flocculent  and  pilous 
covering,  is  evidently  inorganic,  being  merely  a 
crust  of  inspissated  mucus,  originally  secreted 
with  the  calcareous  particles,  and  forming  when 
dry  a  layer  encrusting  the  surface  of  the  shell. 

There  is  yet  another  structure  common  to 
shells  of  this  class,  of  which  it  remains  to  speak, 
namely,  the  enamel  or  pearl,  which  lines  such  por- 
tions of  them  as  are  immediately  in  contact  with 
the  body  of  the  animal ;  this  polished  material 
may  be  likened  to  the  glazing  of  an  earthen- 
ware vessel,  and  is  a  varnish  produced  from 
the  general  surface  of  the  mantle,  by  some  mo- 
dification of  its  secretion  the  nature  of  which 
is  unknown,  and  spread  in  successive  coatings 
over  the  more  coarse  calcareous  matter,  where- 
ever  such  a  polish  becomes  needful. 

Having  thus  briefly  described  the  origin  of  the 
different  parts  of  a  shell  in  the  simple  form  which 
we  have  chosen  as  an  example,  we  shall  now 
proceed  to  examine  the  structure  and  mode  of 
growth  in  others  of  a  more  complicated  aspect. 
The  majority  of  the  Gasteropoda  are  furnished 
with  a  shell  which  has  been  denominated  spiri- 
valve.  Let  the  reader  imagine  the  shell  of  the 
Patella  to  be  lengthened  into  a  long  cone,  which, 
instead  of  preserving  its  symmetrical  form,  is 
twisted  around  a  central  axis,  and  he  will  imme- 
diately understand  the  general  arrangement  of 
the  parts  in  shells  of  this  description.  The  cause 
of  such  an  arrangement  is  owing  to  the  shape 
of  the  body  of  the  animal  inhabiting  the  shell, 
which,  as  it  grows,  principally  enlarges  its  shell 
in  one  direction,  thus  of  course  making  it  form 
a  spire  modified  in  shape  according  to  the  de- 
gree in  which  each  successive  turn  surpasses  in 
bulk  that  which  preceded  it.  The  axis  around 
which  the  spire  revolves  is  called  the  columella, 
and  the  mode  of  revolution  around  this  centre 
gives  rise  to  endless  diversity  in  the  external 


form.  In  the  spirivalve-shelled  Gasteropoda, 
as  in  those  last  described,  we  find  a  difference  in 
structure  between  that  part  of  the  mantle  which 
envelopes  the  viscera,  and  is  always  concealed 
within  the  cavity  of  the  shell,  and  the  more 
vascular  portion  placed  around  its  aperture  : 
the  former  is  thin  and  membranous,  its  office 
being  merely  that  of  thickening  the  shell  by 
the  deposition  of  successive  calcareous  strata 
applied  to  its  inner  side,  and  of  producing  the 
pearly  lining  which  smooths  and  polishes  the 
interior  ;  the  latter  part  of  the  mantle  is  thick, 
spongy,  and  coloured,  secreting  largely  the  cal- 
careous particles  with  which  the  progressive 
amplification  of  the  shell  is  effected  :  this  por- 
tion (fig.  179,  c,)  from  its  thickness,  and  the 


Fig.  179. 


manner  in  which  it  usually  surrounds  the  en- 
trance to  the  shell,  is  generally  termed  the  col- 
lar. In  such  species  as  inhabit  coloured  shells 
we  may  observe  upon  the  surface  of  the  collar 
( fig.  179,  d, )  patches  of  different  colours  corres- 
ponding in  tint  with  the  various  hues  seen  upon 
the  exterior.  These  spots  supply  the  pigment, 
which  being  mixed  up  with  the  earthy  cement 
serving  for  the  enlargement  of  the  shell  stains 
it  with  a  corresponding  tint.  In  many  instances, 
as  in  the  figure,  the  colours  are  continually 
secreted  by  the  dark  spaces,  d,  causing  the 
painted  bands  which  they  produce  to  wind  un- 
interruptedly in  the  direction  of  the  convolu- 
tions of  the  spire,  and  they  may  be  seen  gra- 
dually to  increase  in  breadth  as  the  size  of  the 
animal  enlarges  :  but  more  frequently  it  happens 
that  the  colouring  matter  is  only  furnished  at 
stated  periods,  and  in  such  cases  of  course  the 
shell  will  be  marked  with  spots,  the  intervals  be- 
tween which  will  be  regulated  by  the  frequency 
of  the  supply.  It  will  be  seen  that  by  a  combina- 
tion of  these  circumstances  it  is  easy  to  explain 
how  every  variety  of  marking  may  be  produced.  | 
The  most  conspicuous  exception  to  the  gene- 
ral process  by  which  shells  are  painted,  is  met 
with  in  the  porcellaneous  Couries  (Cyprcea), 
which  at  various  periods  of  their  growth  could 
scarcely  be  recognised  as  belonging  to  the  same 
genus.  In  the  young  animal  the  enlargement 
of  the  shell  is  effected  in  the  ordinary  manner, 
and  its  colours  are  supplied  from  the  surface  of 
the  collar :  in  the  mature  state,  however,  these 
shells  are  coloured  in  a  very  different  manner, 
and  acquire  at  the  same  time  a  great  increase  of 
thickness ;  this  is  effected  by  the  enormous  de- 
velopment of  the  alae  of  the  mantle,  which  in 
the  full-grown  animal  become  so  much  ex- 
tended, that  when  the  creature  is  in  motion  they 
are  laid  over  the  external  surface  of  the  shell  so 
as  entirely  to  conceal  it.  These  alae  contain 
patches  of  pigment  which  secrete  colours  en- 
tirely different  from  those  contained  in  the 
collar,  and  from  their  whole  surface  exudes  a 


GASTEROPODA. 


383 


calcareous  varnish,  which  being  laid  over  the 
exterior  of  the  old  shell  completely  conceals 
the  original  markings  ;  these,  however,  may  be 
again  exposed  on  removing  with  a  file  the  outer 
crust:  a  line,  which  is  generally  very  distinctly 
seen  running  longitudinally  along  the  back  of 
the  shell,  indicates  the  spot  where  the  edges  of 
the  two  alae  of  the  mantle  met  during  the  com- 
pletion of  this  singular  process.  Such  shells 
are  therefore  remarkable  from  the  circumstance 
of  having  their  thickness  increased  by  additions 
to  the  outer  as  well  as  to  the  internal  surface. 

In  terrestrial  shells  it  is  only  when  they  have 
arrived  at  their  full  growth  that  a  rim  or  margin 
is  formed  around  the  aperture,  which  serves  to 
strengthen  the  whole  fabric;  but  in  marine 
shells,  which  attain  to  much  larger  dimensions, 
the  growth  is  effected  at  distinct  periods,  each 
of  which  is  indicated  by  a  well-defined  margin, 
and  these  ridges  remaining  permanent,  the  suc- 
cessive stages  of  increase  may  be  readily  seen. 
At  each  suspension  of  development,  it  is  not 
unusual  to  find  spines  or  fringes,  sometimes 
differently  coloured  from  the  rest  of  the  shell, 
and  not  unfrequently  of  considerable  length. 
In  Jig.  180,  which  represents  the  shell  of  Mure.v 

Fig.  180. 


cornutus,  the  nature  and  arrangement  of  such 
spines  is  well  exemplified.  They  are  all  formed 
by  the  margin  of  the  mantle  which  shoots  out 
into  long  fringes,  encrusting  themselves  with  a 
shelly  covering  ;  each  spine  therefore  is  at  first 
hollow,  and  if  in  many  species  they  are  found 
solid,  it  is  because  the  original  cavity  has  been 
gradually  filled  up  by  the  deposition  of  earthy 
matter  within  it.  The  syphon  with  which  many 
Conchiferous  Gasteropoda  are  provided  is  pro- 
duced in  precisely  the  same  manner,  and  its 
identity  in  form  with  the  other  spines  covering 
the  surface  of  the  shell  is  in  the  annexed  figure 
sufficiently  obvious.  In  many  species,  as  in 
the  beautiful  Turbo  scalaris,  (fig.  181,)  the 
epocha  of  growth  are  only  indicated  by  ridges 
surrounding  the  shell  at  regular  intervals,  each 
of  which  originally  terminated  a  fresh  augmen- 
tation of  its  size.  It  is  difficult  to  imagine  by 
what  influence  these  creatures  are  induced  to 
enlarge  their  habitations  at  such  regular  inter- 
vals, terminating  each  operation  by  a  similar 
margin  ;  some  authors  imagine  that  each  time 
the  creature  emerges  from  its  abode  a  fresh 
addition  is  made  ;  others  that  it  is  dependent 
upon  the  temperature  or  state  of  the  seasons, 
but  without  sufficient  grounds  for  either  of  these 
assertions  ;  it  seems  more  probable  therefore 
that  the  growth  of  the  body  gradually  rendering 
the  former  dimensions  of  the  shell  incommo- 


dious from  time  to  Fig.  181. 

time  renders  these  pe-  ja^ 
riodical  enlargements 
necessary. 

Although  shells 
are  evidently  inorga- 
nic and  extra-vascu- 
lar structures,  it  is 
now  universally  con- 
ceded that  their  in- 
habitants have  the 
power  of  removing 
portions  which  may 
obstruct  their  growth, 
or  needlessly  infringe 
upon  the  limits  of 
their  abode.  In  the 
Murices  we  have  in- 
disputable evidence 
of  this  fact  in  the 
removal  of  such  spines  as  would  interfere 
with  the  revolutions  of  the  shell  around  the 
columella,  and  in  Conus  and  similar  genera 
a  like  faculty  enables  the  animals  to  thin 
the  walls  which  bound  the  inner  whirls 
when  their  original  thickness  is  rendered  un- 
necessary by  the  accession  of  new  turns.  Such 
a  solvent  power  indeed  is  not  only  exer- 
cised upon  their  own  habitations,  but  many 
Gasteropods  are  able  gradually  to  bore  holes  in 
other  shells,  or  perforate  the  rocks  upon 
which  they  reside  to  a  considerable  depth. 
The  mode  in  which  this  is  effected  is,  however, 
still  a  mystery  ;  some  authors  ascribe  it  to  a 
power  of  absorbing  their  shells,  an  expression 
the  vagueness  of  which  is  sufficiently  evident; 
others  ascribe  it  to  some  acid  secretion  at  the 
disposal  of  the  animal;  yet  although  this  ex- 
planation is  certainly  plausible,  when  we  reflect 
that  the  very  structure  which  secretes  this  sup- 
posed acid  is  itself  the  matrix  of  such  abundant 
alkaline  products,  it  is  not  easy  to  imagine  how 
the  same  structure  can  at  the  same  time  furnish 
such  opposite  materials. 

As  we  should  expect  from  the  mode  of  its 
growth,  the  shell  throughout  all  the  Conchi- 
ferous class  is  composed  of  earthy  matter, 
cemented  together  by  an  animal  substance 
easily  separable  by  the  action  of  acids.  In  the 
porcellaneous  shells  the  animal  matter  exists  in 
much  less  quantity  than  in  those  of  a  fibrous 
texture;  in  the  former,  indeed,  Mr.  Hatcbett 
found  that  when  the  carbonate  of  lime,  of 
which  the  earthy  portion  is  almost  entirely 
formed,  is  dissolved  even  by  very  feeble  acids, 
little  or  no  vestige  of  any  membranous  struc- 
ture could  be  perceived,  nor  indeed  could  any 
be  detected,  but  by  the  small  portion  of  animal 
coal  which  was  formed  when  these  shells  had 
been  exposed  for  a  short  time  to  a  low  red 
heat ;  in  others  however,  as  the  Patellae,  a  sub- 
stance was  left  untouched  by  the  acids  which 
had  the  appearance  of  a  yellowish  transparent 
jelly,  by  means  of  which  the  earthy  matter 
had  been,  as  it  were,  cemented  together. 

On  examining  minutely  the  mechanical  ai- 
rangement  of  the  layers  of  which  these  shells 
are  composed,  it  is  found  to  vary  in  different 
kinds,  and  from  this  circumstance  the  fossil 


384 


GASTEROPODA. 


conchologist  may  derive  important  information 
in  examining  mutilated  remnants  sometimes  so 
plentifully  met  with  in  calcareous  strata.  The 
simpler  shells  (Patella,  Fissurella)  are  formed 
of  very  thin,  compact,  and  parallel  layers, 
whilst  in  others  three  distinct  strata  of  fibres, 
each  of  which  assumes  a  different  direction, 
may  be  observed.  The  fibres  composing  the 
external  layer  are  disposed  perpendicularly  to 
the  axis  of  the  shell.  In  the  middle  stratum 
the  fibres  are  placed  obliquely  and  are  slightly 
twisted,  but  so  arranged  that  each  meets  at  an 
obtuse  angle  the  extremity  of  one  of  the  fibres 
composing  the  outer  layer,  and  in  the  internal 
stratum  they  again  assume  a  perpendicular 
direction.  Such  a  disposition  of  the  fibres, 
which  is  met  with  in  all  Siphonibranchiate 
shells,  is  eminently  calculated  to  resist  ex- 
ternal violence  in  whatever  direction  it  may 
act,  and  greatly  contributes  to  the  solidity  of 
the  whole  fabric. 

Operculum. — Many  of  the  spirivalve  Gaste- 
ropoda, especially  such  as  are  aquatic,  are 
provided  with  a  calcareous  plate,  which  is 
placed  upon  the  posterior  surface  of  the  body, 
and  closes  accurately  the  mouth  of  the  shell, 
when  the  animal  is  retracted  within  it.  The 
texture  of  the  operculum  is  sometimes  horny, 
but  it  is  more  frequently  calcareous  and  of  a 
stony  hardness,  its  contour  being  accurately 
adapted  to  the  orifice.  It  is  composed  of 
parallel  fibres  disposed  perpendicularly  to  the 
base  of  the  shell,  and  deposited  in  successive 
layers  around  an  axis,  so  as  to  give  to  the 
whole  structure  the  appearance  of  a  solid 
spirivalve,  as  may  readily  be  seen  on  removing 
it  from  the  animal  and  examining  its  inner 
surface.  Tnis  has  been  looked  upon  by  some 
zoologists  as  analogous  to  the  second  valve  of 
bivalve  Mollusca,  to  which,  but  for  its  want 
of  a  ligamentous  attachment,  it  certainly  bears 
a  distant  resemblance. 

The  deciduous  operculum  of  terrestrial 
Gasteropoda,  or  epiphragma,  as  it  is  usually 
called,  is  a  widely  different  structure,  being 
merely  an  inspissated  secretion,  with  which, 
during  the  period  of  hybernation,  the  entrance 
to  the  shell  is  closed  ;  and  on  removing  the 
outer  plate,  not  unfrequently  a  second  or  even 
a  third  similar  membrane  will  be  found  within, 
forming  additional  safeguards  against  intrusion 
or  the  vicissitudes  of  temperature. 

During  the  progressive  growth  of  the  shell 
the  animal  contained  within  it  necessarily 
changes  its  original  position,  advancing  gra- 
dually as  the  body  enlarges  from  the  earliest 
formed  spires  towards  the  aperture,  as  may 
easily  be  proved  by  sawing  off  the  apex  of  a 
spirivalve  shell  containing  the  living  animal. 
This  circumstance  is  remarkably  conspicuous 
in  some  of  the  Bulimi  ( Bulimus  decoltutus), 
enabling  the  occupant,  as  it  grows,  to  break 
off  the  turns  of  its  spire  which  first  contained 
it,  so  that  at  the  latter  period  of  its  life  it  does 
not  retain  any  part  of  its  original  shell.  The 
mode  in  which  this  advancement  is  effected  is 
a  subject  of  much  curiosity,  as  it  involves  a 
power  of  detaching  the  muscles  connecting 
the  creature  with  its  abode,  from  the  place 


where  they  were  originally  fixed,  and  forming 
a  new  connexion  with  the  shell ;  but  whether 
this  is  effected  by  the  removal  of  the  original 
fibres  and  the  production  of  others  more  ante- 
riorly, as  is  believed  by  some,  or  whether,  as  is 
more  probably  the  case,  the  creature  has  a 
power  of  changing  the  attachment  of  its  re- 
tractor muscle  at  pleasure,  is  still  a  matter  of 
uncertainty. 

Organs  of  digestion. — We  shall  not  be  sur- 
prised to  find  that  in  a  class  so  extensive,  and 
composed  of  individuals  living  in  such  diver- 
sified circumstances,  the  alimentary  organs  are 
much  modified  in  form  in  different  species, 
according  to  the  nature  of  the  food  with  which 
they  are  nourished. 

Mouth. — In  most  instances  the  mouth  pre- 
sents the  appearance  of  a  retractile  proboscis, 
which  can  be  protruded  or  shortened  at  the 
will  of  the  animal,  but  unprovided  with  jaws 
or  any  apparatus  for  mastication  ;  it  is  in  such 
cases  a  muscular  tube,  formed  of  longitudinal 
fibres  prolonged  from  the  common  parietes  of 
the  body,  and  of  circular  muscles,  the  former 
serving  for  the  retraction  of  the  organ,  the 
latter  causing  its  elongation  by  their  successive 
action ;  by  means  of  this  simple  structure 
every  movement  requisite  for  the  prehension 
of  food  is  effected.  At  the  bottom  of  the  tube 
is  a  narrow  vertical  aperture,  the  edges  of  which 
are  slightly  cartilaginous,  and  behind  this  is 
the  tongue  armed  with  spines  variously  dis- 
posed;  the  aliment  therefore,  having  been 
forced  by  the  contractions  of  the  proboscis 
through  the  aperture  at  its  termination,  is  re- 
ceived by  the  tongue,  and  by  the  aid  of  the 
latter  organ  is  propelled  into  the  oesophagus 
without  mastication  or  any  preparatory  change. 

In  Buccinum  and  other  syphoniferous  ge- 
nera, the  structure  of  the  proboscis  is  much 
more  complicated  and  curious,  (Jig.  182.) 
"  The  proboscis,  which  carries  with  it  the 
oesophagus  in  its  different  states  of  protrusion, 
is  organised  with  wonderful  artifice,  being  not 
only  capable  of  flexion  in  every  direction  com- 
bined with  limited  power  of  retraction  or 
elongation,  but  it  can  be  entirely  lodged  in  the 
interior  of  the  body,  folded  within  itself,  so 
that  that  half  which  is  nearest  the  base  en- 
closes the  other  portion  :  from  this  position  it 
is  protruded  by  unfolding  itself  like  the  finger 
of  a  glove  or  the  tentacle  of  a  snail,  only  it  is 
never  completely  inverted.  We  may  repre- 
sent it  as  composed  of  two  flexible  cylinders 
(Jig.  182,  a,  b,)  one  inclosed  within  the  other, 
the  upper  borders  of  which  join,  so  that  by 
drawing  outwards  the  inner  cylinder,  it  is 
elongated  at  the  expense  of  the  other,  and 
on  the  contrary,  by  pushing  it  back,  the  internal 
cylinder  becomes  lengthened  by  its  shortening. 
These  cylinders  are  acted  upon  by  a  number 
of  longitudinal  muscles  (c,  c),  all  very  much 
divided  at  each  extremity,  the  internal  or  su- 
perior divisions  being  fixed  to  the  parietes  of 
the  body,  whilst  at  the  other  end  they  are 
attached  to  the  inner  wall  of  the  internal  tube 
(a)  of  the  proboscis,  along  its  whole  length, 
extending  even  to  its  extremity  ;  their  action  is 
obviously  to  draw  the  inner  cylinder,  and  con- 


GASTEROPODA. 


385 


182.  sequently   the  entire 

proboscis  inward.  This 
being  done,  a  great 
part  of  the  inner  sur- 
face of  the  inner  cy- 
linder becomes  a  part 
of  the  external  surface 
of  the  outer  cylinder, 
whilst  the  contrary  oc- 
curs when  the  pro- 
boscis is  elongated  and 
protruded. 

The  elongation  of 
the  inner  cylinder  by 
the  unfolding  of  the 
outer,  or  what  is  the 
same  thing,  the  pro- 
trusion of  the  probos- 
cis, is  effected  by  the 
intrinsic  annular  mus- 
cles which  assist  in 
forming  the  organ  ; 
they  surround  it 
throughout  its  whole  length,  and  by  their  suc- 
cessive contractions  force  it  outwards;  one  espe- 
cially, seen  at  b,  placed  near  the  junction  of  the 
extremity  of  the  outer  cylinder  with  the  inte- 
guments of  the  head,  which  is  stronger  than 
the  rest.  When  the  proboscis  is  protruded, 
its  retractor  muscles  acting  separately,  bend  it 
in  every  direction,  being  in  this  case  antago- 
nists to  each  other.  The  internal  cylinder 
incloses  the  tongue  (/),  the  salivary  canals  (e), 
and  the  gTeater  part  of  the  oesophagus  (d),  but 
its  principal  use  is  to  apply  the  extremity  of 
the  tongue  to  such  objects  as  the  animal  would 
suck  or  erode  by  its  armed  surface. 

In  Aplysia,  Akera,  and  others,  the  mouth 
consists  of  a  fleshy  mass  of  considerable 
strength,  to  which  are  attached  muscular  bands 
proceeding  from  the  sides  of  the  body,  serving 
for  its  movements,  some  drawing  it  forwards 
whilst  others  retract  it,  but  there  are  no  jaws 
nor  anything  equivalent  to  them,  except  the 
cartilaginous  hardness  of  the  lips. 

But  in  such  of  the  Gasteropoda  as  devour 
vegetable  matter,  the  mouth,  instead  of  being 
a  proboscis,  consists  of  a  strong  muscular 
cavity,  inclosing  a  dental  apparatus  adapted  to 
the  division  of  the  food.  In  the  Snail,  Slug, 
Limnanis,  Planorbis,  &c,  this  is  a  single  cres- 
cent-shaped horny  tooth,  attached  to  the  upper 
surface,  and  furnished  along  its  opposite  edge 
with  sharp  points,  separated  by  semicircular 
cutting  spaces,  admirably  adapted  for  the  di- 
vision of  vegetable  food. 

The  dental  organs  of  Titonia  and  Scylloea 
are,  however,  still  more  perfectly  contrived  for 
such  a  purpose.  The  muscular  mass  of  the 
mouth  is  strong  and  powerful,  but  instead  of 
the  single  tooth  of  the  Snail,  it  is  armed  with 
two  cutting  blades  (Jig.  183,  b,  b),  horny  in 
their  texture  and  exceedingly  sharp,  resembling 
in  every  respect  a  pair  of  strong  curved  shears, 
from  which  in  fact  they  only  differ  in  the  mode 
of  their  union,  the  spring  of  the  one  being 
replaced  by  an  articulation  (c)  inclosed  in  a 
synovial  capsule.  These  blades  are  approx- 
imated by  strong  muscular  fibres,    and  few 


JW183-. 


animal  structures  can  resist  their  edge.  The 
lips  (/)),  which  are  placed  in  front  of  these 
teeth,  are  strong  and  very  flexible,  forming 
a  muscular  tube,  by  means  of  which  the  food 
is  seized  and  brought  within  the  power  of  its 
formidable  jaws,  and  then  the  divided  morsels, 
being  seized  by  the  horny  teeth  which  invest 
the  tongue  (d),  are  conveyed  into  the  oesopha- 
gus. 

Tongue. — The  tongue  in  these  Mollusca  is 
generally  a  very  important  organ,  serving  not 
only  as  a  necessary  auxiliary  in  deglutition,  but 
often  as  a  means  of  eroding  the  food  :  in  fact, 
in  one  tribe  only,  Tlief/ii/a,  is  it  found  to  be 
deficient.  In  most  of  the  proboscidean  spe- 
cies the  tongue  is  short,  and  covered  with 
sharp,  horny,  and  recurved  spines,  which, 
seizing  the  morsels  of  food  taken  into  the 
mouth  by  a  sort  of  peristaltic  motion,  push  it 
backwards  into  the  oesophagus.  In  some  ge- 
nera which  have  no  proboscis,  the  tongue  is 
of  extraordinary  length  ;  thus  in  Haliotis  it 
is  half  as  long  as  the  body,  and  in  Patella, 
Turbo,  Pica,  and  others,  it  much  exceeds  in 
length  the  entire  animal.  The  tongue  of  Pa- 
tella, which  is  three  times  the  length  of  the 
body,  is  represented  at  fig.  184  ;  it  is  supported 
by  two  cartilaginous  pieces  (b,  b)  placed  on  each 

Fig.  184. 


side  of  its  root ;  from  these  arise  strong  and 
short  muscular  bands,  which  wield  the  or- 
gan. The  surface  of  this  singular  tongue, 
a  magnified  view  of  which  is  given  at  B, 
is  armed  with  minute  though  strong  teeth, 
placed  in  transverse  rows  and  arranged  in 
three  series ;  each  central  group  consists 
of  four  spines,  while  those  on  the  sides  con- 
tain but  two  a-piece.  It  is  only  at  its  an- 
terior extremity,  however,  that  the  tongue  so 
armed  presents  that  horny  hardness  needful 
for  the  performance  of  its  functions,  the  posterior 


386 


GASTEROPODA. 


part  being  comparatively  soft ;  it  would  seem, 
therefore,  that  in  proportion  as  the  anterior  part 
is  worn  away,  the  parts  behind  it  assume 
gradually  the  necessary  firmness  and  advance 
to  supply  its  place.  The  action  of  this  curious 
instrument  is  as  follows: — in  the  upper  part 
of  the  circumference  of  the  mouth  we  find  a 
semicircular  horny  plate,  resembling  an  upper 
jaw,  and  the  tongue,  by  triturating  the  food 
against  this,  gradually  reduces  substances  how- 
ever hard.  On  opening  the  Patella,  the  tongue 
is  found  doubled  upon  itself,  and  folded  in  a 
spiral  manner  beneath  the  viscera. 

The  tongue  of  Oscabrio  resembles  that  of 
the  Patella,  except  in  its  armature,  being  fur- 
nished on  each  side  with  a  series  of  hooked  and 
three-pointed  scales,  and  another  set  of  long, 
sharp,  and  recurved  spines,  whilst  its  centre  is 
simply  studded  with  tubercles.  In  Turbo  pica 
the  scales,  which  are  cutting  and  denticulated, 
are  arranged  transversely  along  its  surface. 

The  tongue  of  Buccinum  (Jig.  \82,J'),  is 
placed  at  the  extremity  of  the  proboscis,  form- 
ing a  most  extraordinary  apparatus,  capable  of 
destroying  by  its  constant  action  the  hardest 
shells ;  externally  it  resembles  rather  a  mouth 
than  a  tongue,  being  divided  into  two  lips, 
each  of  which  is  studded  with  sharp  horny 
teeth.  These  lips  are  supported  upon  two 
cartilages  which  occupy  the  anterior  half  of  the 
proboscis,  and  are  moved  upon  each  other  by 
strong  muscular  fasciculi  (/;)  in  such  a  manner 
that  the  spines  which  arm  the  surface  of  the 
organ  are  alternately  erected  and  depressed  by 
their  action,  a  movement  the  constant  repe- 
tition of  which  soon  wears  away  the  substances 
upon  which  it  is  made  to  act.  This  spiny 
tongue  is  situated  just  within  the  entrance  to 
the  oesophagus  (d),  and  besides  acting  upon 
foreign  bodies  will  materially  assist  in  pro- 
pelling the  food  into  that  tube. 

In  other  Gasteropods  the  tongue  is  short 
and  merely  an  organ  of  deglutition  :  thus,  in 
Aplysiu  it  is  broad,  heart-shaped,  and  studded 
with  sharp  points.  In  Onchidium  and  Doris, 
the  surface  is  marked  with  transverse  grooves, 
which  are  crossed  at  right  angles  by  others  of 
great  fineness.  And  in  the  Snail  and  Slug,  in 
which  the  surface  of  the  tongue  is  similarly 
marked,  the  striae  are  so  delicate  that  they  can 
only  be  seen  with  a  microscope. 

Alimentary  canal.  —  We  shall  commence 
our  description  of  the  intestinal  canal  of  the 
Gasteropod  Mollusca  by  the  examination  of 
the  simpler  forms  which  it  presents.  In  the 
Snail  (Jig.  190),  the  whole  alimentary  tube 
{e,  f,  g,  k)  is  thin  and  membranous.  The 
stomach,  which  is  merely  a  dilatation  of  the 
oesophagus,  is  semitransparent,  but  studded 
with  opaque  points  and  internally  folded  into 
delicate  longitudinal  plicae.  From  this  arises 
an  intestine,  of  considerable  length,  without 
cceca,  valves,  or  remarkable  appearance  inter- 
nally, except  near  its  termination,  where  the 
orifices  of  minute  follicles  may  be  detected  ; 
the  intestine  having  performed  several  con- 
volutions enveloped  in  the  masses  of  the  liver, 
with  which  it  is  connected  by  cellulosity 
and  numerous  vessels,  at  last  runs  along  the 


margin  of  the  pulmonary  cavity,  close  to  the 
orifice  of  which  it  terminates.  In  Vaginulus 
the  arrangement  is  nearly  similar  (Jig.  189, 
g,  h,  ?.)  In  Tritonia  and  Doris  the  structure 
of  the  digestive  tube  is  equally  simple,  and  in 
these  as  well  as  in  the  majority  of  the  Gaste- 
ropoda the  only  remarkable  differences  are 
found  in  the  proportional  size  of  the  stomach 
and  the  length  of  the  intestinal  convolutions. 
In  Doris  we  find  near  the  orifices  by  which 
the  bile  is  poured  into  the  stomach,  an  aper- 
ture communicating  with  a  round  vesicle  or 
ccecum,  the  inner  surface  of  which  is  evidently 
glandular,  and  from  its  large  supply  of  blood 
derived  from  one  of  the  hepatic  arteries,  pro- 
bably furnishing  an  abundant  secretion  ana- 
logous to  that  of  the  pancreas.  In  Phasia- 
nella  the  stomach  is  very  voluminous  and 
sacculated  internally.  In  Buccinum  the  di- 
gestive apparatus  is  more  complicated  in  its 
structure.  The  oesophagus  commences,  as  we 
have  already  seen,  at  the  extremity  of  the  pro- 
boscis, and  of  course  follows  all  the  motions 
of  that  organ;  when  the  proboscis  is  protruded 
in  search  of  prey,  the  gullet  is  straight  and 
adapted  to  the  reception  of  food  ;  but  when  the 
proboscis  is  retracted  within  the  body,  the 
oesophagus  is  bent  upon  itself,  so  as  to  be 
partially  contained  within  the  proboscis,  whilst 
the  greater  portion  is  folded  beneath  that  organ 
in  its  retroverted  state.  After  making  another 
fold  it  dilates  into  a  small  crop,  the  lining  of 
which  is  plicated  in  the  direction  of  its  axis, 
and  to  this  succeeds  the  stomach,  which  is  a 
moderately  sized  round  cavity,  irregularly  ru- 
gose internally.  The  intestine  is  very  short, 
and  has  a  small  ccecum  appended  to  its  side  ; 
it  terminates  in  a  capacious  rectum,  placed, 
as  is  invariably  the  case,  in  the  vicinity  of  the 
respiratory  cavity,  and  having  its  lining  mem- 
brane gathered  into  prominent  longitudinal 
rugae.  Many  of  the  Gasteropoda  are  provided 
with  several  digestive  cavities,  resembling  in 
some  degree  the  stomachs  of  ruminating  Mam- 
malia. In  Janthina,  which  is  furnished  with 
a  proboscis  like  that  of  the  Buccinum,  the 
oesophagus  arising  from  this  terminates  by  a 
narrow  slit  in  a  membranous  cavity  or  first 
stomach,  to  which  succeeds  a  second,  having 
thicker  walls  and  plicated  internally.  The  in- 
testine is  extremely  short,  terminating  as  usual 
in  the  neighbourhood  of  the  respiratory  cavity. 
In  Pleurobranchus  the  resemblance  of  the 
stomachs  to  those  of  a  ruminating  quadruped 
is  very  striking.  The  first  stomach  (fig.  185, 
a),  which  is  membranous,  receives  the  bile  by 
a  large  orifice  (b)  placed  near  its  communi- 
cation with  the  second  digestive  cavity  (c), 
which  is  smaller  and  more  muscular;  to  this 
succeeds  a  third  (d),  the  sides  of  which  are 
gathered  into  broad  longitudinal  lamellae,  pre- 
cisely similar  to  those  of  a  ruminant ;  and 
to  render  the  analoay  still  more  perfect,  a 
groove  is  found  running  along  the  walls  of  the 
second  cavity  from  one  orifice  to  the  other, 
apparently  subservient  to  rumination.  The 
fourth  stomach  (e)  is  thin,  and  its  walls  smooth. 
This  animal  lives  on  Alcyonia  and  small  Zoo- 
phytes. 


GASTEROPODA. 


387 


P<g.  185.  Many  Gasteropoda  which 

devour  shell-fish  and  other 
hard  materials  have  a  true 
gizzard  adapted  to  break  in 
pieces  such  food ;  this  is  the 
case  with  Thcthys,  an  animal 
whose  mouth  is  totally  desti- 
tute of  dental  organs,  but 
their  want  is  supplied  by  a 
fleshy  gizzard  resembling  that 
of  a  bird,  having  its  interior 
lined  with  a  dense  cartilagi- 
nous membrane,  like  that 
which  lines  the  gizzard  of 
graminivorous  fowls,  and  in 
its  cavity  shells  of  Mollusca 
and  Crustaceans  are  found 
comminuted  by  its  action. 
In  LimntEUS  we  find  a  gizzard 
strictly  analogous  in  structure 
to  that  of  a  granivorous  bird  : 
it  presents  two  dilatations, 
one  at  the  cardiac,  the  other 
at  the  pyloric  extremity, 
whilst  the  middle  portion  is 
occupied  by  two  strong  mus- 
cles, united  at  the  sides  by 
tendinous  bands.  The  gizzard 
of  Planorbis  is  precisely 
similar  to  that  of  Limnaeus.  In  Onchidium 
the  muscular  gizzard  is  followed  by  two  other 
stomachs,  the  lining  membrane  of  that  which 
immediately  succeeds  it  being  gathered  into 
large  folds,  which  must  greatly  retard  the  pas- 
sage of  the  aliment;  while  the  third  cavity, 
which  is  short  and  cylindrical,  is  likewise  lined 
with  a  membrane  folded  into  more  delicate 
plicae,  affecting  a  longitudinal  direction. 

There  are  some  families  in  this  class  which 
are  provided  with  a  still  more  elaborate  appa- 
ratus for  the  preparation  of  their  food,  their 
stomachs  being  armed  internally  with  teeth 
variously  disposed,  and  on  many  accounts 
extremely  curious.  In  all  the  Bullae  (Akera) 
the  gizzard  contains  three  plates  of  stony  hard- 
ness attached  to  its  walls,  and  so  disposed  that 
they  are  evidently  powerful  agents  in  the  tritu- 
ration of  the  food.  In  Bulla  lignaria  (fig.  186) 
two  of  these  teeth  are  place  1 
on  either  side  of  the  gizzard, 
into  the  cavity  of  which  they 
project,  and  are  united  to 
each  other  by  strong  muscular 
bands  ;  the  third  piece  is 
smaller  than  the  other  two, 
but  similarly  imbedded  in 
radiating  muscles,  whose 
action  must  powerfully  grind 
down  the  substances  which 
come  under  the  influence  of 
this  singular  mill.  In  the  other  Bulla  the 
structure  of  the  gizzard  is  the  same,  but  the 
bony  plates  differ  slightly  in  form  and  arrange- 
ment. In  all,  however,  the  fragments  of  shells 
and  other  hard  substances  found  in  it  attest  the 
efficacy  of  the  apparatus. 

The  gizzard  of  Scyllaa  (fig.  187,  e)  is,  ex- 
ternally, a  strong  fleshy  cylinder,  and  when 
this  is  opened  there  are  found,  firmly  im- 


bedded in  its  muscular  walls,  twelve  horny 
plates,  which  are  extremely  hard  and  as  sharp 
as  the  blades  of  a  knife ;  their  edges  are  dis- 


ie.  187. 


posed  in  the  direction  of  the  axis  of  the  organ, 
and  as  they  project  considerably  into  its  cavity, 
their  action  upon  the  contents  of  the  gizzard 
must  be  sufficiently  evident. 

Aplysia,  however,  furnishes  us  with  the 
most  curious  form  of  these  stomachal  teeth. 
The  oesophagus,  which  is  comparatively  narrow 
at  its  commencement,  soon  dilates  into  a  capa- 
cious crop,  which  is  generally  found  filled  with 
pieces  of  fucus  and  the  fragments  of  shells.  To 
th  is  crop  succeeds  a  short  cylindrical  gizzard  with 
strong  and  muscular  walls,  and  after  the  gizzard 
we  find  a  third  stomach  which  leads  to  the 
intestine.  On  opening  the  gizzard  and  third 
stomach  (fig.  188)  they  are  found  to  have  their 


Fig.l 


388 


GASTEROPODA. 


interior  armed  in  a  manner  which  is  probably 
unique.  The  sides  of  the  gizzard  (b)  are 
covered  with  pyramidal  plates  of  a  rhomboidal 
figure,  the  apices  of  which  resemble  the 
tubercles  found  upon  the  grinding  surfaces  of 
the  human  molar  teeth.  Of  these  there  are 
twelve  larger  plates  arranged  in  quincunx, 
besides  several  smaller  ones  placed  near  the 
entrance  of  the  organ.  These  teeth  are  of  a 
horny  nature  and  formed  of  lamina;  parallel  to 
their  bases  :  their  adhesion  to  the  surface  of 
the  lining  membrane  is  so  slight  that  they  are 
detached  by  the  slightest  effort,  without  leaving 
any  trace  of  membrane  or  other  bond  of  union, 
the  place  of  their  attachment  being  only  indi- 
cated by  a  smooth  and  prominent  surface, 
corresponding  in  shape  to  the  base  of  each 
tooth.  The  apices  of  all  these  teeth  meet  in  the 
centre  of  the  gizzard,  and  whatever  passes 
through  that  cavity  must  be  bruised  by  then- 
action. 

The  third  stomach  (<7)  is  armed  with  teeth  of 
a  totally  different  nature.  These  are  little 
conical  hooks  (c)  attached  to  one  side  of  the 
organ  only,  and  as  little  adherent  in  the  dead 
animal  as  are  the  pyramids  of  the  gizzard 
towards  which  their  points  are  directed.  In 
the  figure  many  have  fallen  off,  leaving  slightly 
elevated  spots  indicative  of  the  place  of  then- 
attachment.  Near  the  pylorus  is  a  large  aper- 
ture communicating  with  a  caecum  of  consider- 
able size  (/'),  evidently  identical  with  the 
spiral  ccecum  of  the  Cephalopoda  both  in  its 
position  and  relation  to  the  insertion  of  the 
biliary  canals  (e),  forming,  as  in  Fishes,  the 
rudiment  of  a  pancreas.  From  the  orifice  of 
the  coscum  a  ridge  is  prolonged  into  the  com- 
mencement of  the  intestine  (g). 

Accessory  glands. — The  auxiliary  chylopoietic 
secretions  found  in  the  Gasteropoda  are  gene- 
rally only  two,  the  salivary  and  the  hepatic. 
In  some  rare  instances  already  adverted  to,  as 
in  Doris  and  Aplysia,  we  may  likewise  add 
the  pancreatic  furnished  by  the  coeca,  which  in 
those  genera  terminate  in  close  vicinity  with 
the  ducts  issuing  from  the  liver,  and  which, 
from  every  analogy,  represent  the  pancreas  of 
vertebrate  animals. 

The  salivary  glands  are  constantly  present 
and  seem  to  present  a  size  and  importance 
corresponding  with  the  mode  in  which  the 
mastication  of  the  food  is  accomplished.  In 
those  genera  which  are  provided  with  a  cutting 
apparatus  placed  in  the  mouth,  they  are  very 
largely  developed,  as  also  in  most  of  the 
ptoboscidean  species,  and  it  is  only  in  the 
Cyclobranchiate  order,  where  the  long  spiral 
tongue  is  used  rather  for  the  abrasion  than  the 
mastication  of  the  food,  that  they  become  small, 
and,  in  a  very  few  instances,  undistinguishable. 
In  jig.  190,  which  represents  the  viscera  of  the 
Snail,  these  glands  are  marked  with  the  letters 
««,  and  this  engraving  will  give  a  good  idea  of 
the  general  structure  which  they  present,  and  of 
the  ordinary  termination  of  the  ducts  which  pour 
the  saliva  into  the  oral  cavity.  The  glands 
are  placed  along  the  sides  of  the  stomach, 
which  they  partially  invest,  and  sometimes 
those  of  the  opposite  sides  are  intimately  united 


with  each  otlier;  their  colour  is  whitish  and 
semi-transparent,  and  they  are  formed  of  small 
lobes,  which,  in  many  species  where  their 
texture  is  less  compact,  may  be  distinctly  seen 
to  be  formed  of  the  ramifications  of  their 
arborescent  ducts,  each  ultimate  division  of 
which  is  terminated  by  a  secreting  granule. 
In  Vaginulus  (Jig.  189)  the  salivary  glands  are 
small,  but  in  addition  to  the  ordinary  struc- 
ture ( /')  we  find  an  additional  tube  or  slender 
ccecum  (*/),  which,  lying  at  first  upon  the 
stomach,  passes  through  tlie  nervous  collar  to 
join  the  duct  by  which  the  saliva  is  discharged. 
The  secondary  divisions  of  the  ducts  gradually 
unite  to  form  an  excretory  canal  for  each  of  the 
two  glands,  which  invariably  pour  the  salivary 
secretion  into  the  mouth  in  the  vicinity  of  the 
tongue.  When  very  small,  as  in  Testacella, 
Onchidium,  and  llaliotis,  they  are  found  to  be 
merely  arborescent  tufts  placed  on  each  side  of 
the  oral  mass.  In  all  the  Pectinibranchiate  order, 
where  the  mouth  is  convened  into  a  protrusible 
proboscis,  the  glands  themselves  (fig.  182,  i) 
are  found  within  the  visceral  cavity,  and  their 
ducts  (e,  e)  are  very  long  and  tortuous  so  as  to 
follow  the  movements  of  the  proboscis  in  which 
they  are  lodged,  running  in  contact  with  the 
oesophagus  to  open  at  the  extremity  of  that 
tube  on  each  side  of  the  spiny  tongue;  it  is 
even  probable  that  the  secretion  which  they 
furnish  at  that  point  may  assist,  in  some  mea- 
sure, in  the  destruction  of  the  shells  and  other 
hard  bodies,  which  are  submitted  to  the  con- 
tinued action  of  this  organ. 

In  Doris  and  Pleurobranchus  a  glandular 
structure  of  considerable  size  is  found  near  the 
commencement  of  the  oesophagus,  which  is  of 
a  brownish  colour  and  plentifully  furnished 
with  bloodvessels.  Tins  has  been  looked  upon 
as  an  auxiliary  salivary  organ,  but  as  its  duct 
has  not  been  as  yet  satisfactorily  traced,  its  real 
nature  is  unknown  :  but  in  Janthina  there  are 
distinctly  four  salivary  glands,  each  furnishing 
a  distinct  duct;  two  of  these  run,  as  in  Bucci- 
num,  to  the  extremity  of  the  proboscis,  whilst 
the  other  pair  empties  the  secretion  of  the 
corresponding  glands  into  the  commencement 
of  the  oesophagus. 

Biliary  system. — The  liver  throughout  the 
whole  class  is  of  great  comparative  size,  en- 
veloping the  convolutions  of  the  intestines  and 
filling  a  large  portion  of  the  visceral  cavity. 
That  of  the  Snail  consists  of  four  large  lobes 
(fig.  190,  h ),  each  divisible  into  lobules,  and 
these  again  into  secreting  granules,  from  each 
of  which  issues  an  excretory  duct.  The  ducts 
gradually  unite  into  larger  trunks,  so  that  the 
whole  organ,  when  unfolded,  accurately  repre- 
sents a  bunch  of  grapes,  the  stem  of  which  would 
be  the  common  biliary  duct.  In  the  same  ani- 
mal the  excretory  ducts  from  each  of  the  divisions 
of  the  liver  unite  into  one  canal,  which  opens  into 
the  pyloric  extremity  of  the  stomach  (g)  in 
such  a  manner  that  as  much  bile  must  be 
poured  into  the  stomach  itself  as  into  the  com- 
mencement of  the  intestine.  In  the  Slug  the 
liver  consists  of  five  lobes,  and  from  these  are 
derived  two  distinct  biliary  canals,  which  open 
separately  into  the  intestine,  one  on  each  side 


GASTEROPODA, 


389 


of  the  pylorus.  A  similar  disposition 
in  Vaginulus  (fig.  189,  /,  h'). 


Fig.  189. 


In  Scyllea  the  liver  (fig.  187,  d)  is  divided 
into  six  small  and  detached  round  masses,  the 
excretory  ducts  of  which  open  above  the  point 
where  the  oesophagus  joins  the  singularly  armed 
gizzard  (c).    The  liver  of  Aplyslu  is  very  large 
and  forms  three  principal  masses,  among  which 
are  seen  the  convolutions  of  the  intestine.  The 
biliary  canals  are  very  wide  and  open  into  the 
third  stomach  near  the  aperture  communicating 
with  the  rudimentary  pancreas  (fig.  188,  e). 
In  Testacella  Haliotoidea  there  are  two  livers 
perfectly  distinct  from  each  other,  and  from 
each  arises  a  proper  duct,  which  opens  sepa- 
rately into  the  commencement  of  the  intestine 
near  its  origin.    Onchidium  furnishes  us  with 
a  still  more  curious  arrangement,  being  pro- 
vided with  three  distinct  livers,  pouring  their 
secretions  by  separate  canals  into  different  parts 
of  the  alimentary  tube.    Each  portion  perfectly 
resembles  the  others  in  external  appearance, 
and  in  structure  as  well  as  in  the  nature  of 
their  respective  secretions.  The  excretory  canal 
which  proceeds  from  the  largest  mass  enters 
the  oesophagus,  discharging  itself  near  to  its 
cardiac  termination ;  the  duct  of  the  second 
terminates  near  the  same  point,  whilst  the  bile 
produced  by  the  third  is   poured  into  the 
gizzard  itself.    The  insertion  of  the  two  former 
above  the  gizzard  would  seem  intended  for  the 
same  purpose  as  the  abundant  secretion  which 
is  poured  into  the  ventriculus  succenturiatus  of 
Birds,  namely,  to  moisten  the  food  before  its  in- 
troduction into  the  gizzard  ;  it  is,  however,  sin- 
gular to  find  the  biliary  fluid  employed  for  this 
purpose  ;  nor  is  the  insertion  of  the  third  duct 
into  the  first  of  the  three  stomachs  of  this  animal 
less  extraordinary,  a  similar  arrangement  occur- 


ring only  in  a  few  fishes,  as  in  the  Diodon 
Mala. 

The  liver  of  Doris  is  very  large,  and  not 
only  is  the  bile  which  it  secretes  discharged  by 
large  and  numerous  ducts  into  the  stomach,  so 
wide,  indeed,  that  it  is  difficult  to  conceive 
how  the  food  is  prevented  from  entering  them, 
but  moreover  the  liver  furnishes  a  second  duct 
of  large  calibre,  which  opens  externally  in  the 
vicinity  of  the  anus.    A  part  of  the  bile  in  this 
case  is  evidently  excrementitious,  as  there  is 
no  doubt  that  the  second  canal  takes  its  origin 
from  the  substance  of  the  liver.    "  This,"  says 
Cuvier  speaking  upon  this  subject,  "  is  the 
first  instance  of  the  kind  which  I  have  met 
with,  and  the  fact  was  sufficiently  singular  to 
make  me  hesitate  long  and  examine  the  matter 
with  all  possible  precaution  before  admitting 
it.    It  is  only  by  one  supposition  that  it  can 
be  explained  otherwise, — namely,  that  the  lobes 
of  two  different  glands  are  so  interwoven  that 
they  are  not  to  be  distinguished  from  each 
other,  one  portion  producing  bile  used  in  the 
process  of  digestion,  and  the  other  secreting  a 
fluid  which  escapes  by  the  canal  in  question." 
Before  its  termination  externally,  the  secondary 
duct  communicates  by  a  short  canal  with  a 
lateral  receptacle,  which  forms  a  kind  of  gall- 
bladder,  having  its  lining  membrane  much 
corrugated  and  its  walls  apparently  muscular  ; 
this  is  probably  a  reservoir  for  the  excremen- 
titious fluid,  in  which  it  may  be  retained  until 
the  animal  feels  its  discharge  necessary.  There 
is  reason  to  suspect  that  the  fluid  thus  furnished 
is  a  colouring  matter,  used  as  a  means  of  de- 
fence, and  expelled  like  the  ink  of  the  cuttle-fish 
on  the  approach  of  danger,  but  the  matter  is 
undecided. 

The  bile  is  in  all  cases  produced  from  arte- 
rial blood,  and  the  liver  is  provided  with  but 
one  system  of  veins  answering  to  the  hepatic. 

Organs  of  respiration. — The  respiratory  or- 
gans of  the  Gasteropoda  are  found  to  be  con- 
structed upon  very  various  principles,  adapted 
to  the  medium  which  they  inhabit,  or  the  pecu- 
liar exigencies  of  the  individuals  composing 
each  order.  Nevertheless  in  different  groups 
allied  by  the  generalities  of  their  organization, 
the  respiratory  system  is,  in  most  instances, 
found  to  be  constructed  upon  the  same  plan, 
and  this  circumstance  more  than  any  other  has 
rendered  the  position  and  nature  of  the  respira- 
tory organs  the  most  eligible  basis  of  classifica- 
tion. On  looking  over  the  table  which  we 
have  given  at  the  commencement  of  this  ar- 
ticle, the  reader  will  perceive  at  once  that  the 
names  by  which  the  different  orders  are  desig- 
nated indicate  the  general  disposition  of  the 
pulmonary  or  branchial  appendages,  and  we 
shall  therefore  follow  the  arrangement  there 
adopted  in  considering  more  minutely  the  pe- 
culiarities belonging  to  each. 

The  first  or  Nudibranchiate  order  is  distin- 
guished by  having  the  breathing  apparatus  per- 
fectly exposed  to  the  influence  of  the  surround- 
ing medium,  which  in  all  the  genera  belonging 
to  this  division  is  the  water  of  the  ocean  ;  the 
branchiae  constantly  assume  the  shape  of  arbo- 
rescent tufts,  placed  in  different  situations  upon 
the  dorsal  aspect  of  the  animal.    In  Doris  (see 


390 


GASTEROPODA. 


article  Circulation,  Jig.  321,  vol.  i.  p.  649,) 
they  form  a  circle  around  the  anus.  In  Trito- 
nia  they  are  disposed  in  two  rows  along  the 
sides  of  the  animal,  extending  from  one  extre- 
mity of  the  body  to  the  other.  In  Scyllaa  they 
consist  of  little  tufts  irregularly  disseminated 
over  the  surface  of  the  back  and  upon  the  fleshy 
alae  projecting  therefrom.  In  Glaucus  they  form 
on  each  side  three  large  and  palmated  fins, 
being  used  as  agents  of  progression  as  well  as 
instruments  for  the  purification  of  the  blood. 
In  (Eolis  the  branchiae  assume  the  shape  of  long 
riband-like  lamella?  disposed  in  imbricated 
rows ;  but  whatever  their  form  their  structure 
is  essentially  the  same,  each  tuft  or  lamella 
containing  the  ramifications  of  the  branchial 
vessels,  and  effecting  the  oxygenisation  of  the 
blood  by  the  extent  of  surface  which  they  ex- 
pose to  the  action  of  the  surrounding  water. 

In  the  Infero-brunchiata  the  respiratory  tufts 
or  plates  are  arranged  around  the  circumference 
of  the  body,  lodged  in  a  deep  groove  between 
the  margin  of  the  foot  and  the  edge  of  the  man- 
tle which  covers  the  back.  The  Tectibran- 
chiata  have  the  branchiae  covered  by  a  little 
fold  or  operculum  formed  by  a  duplicature  of 
the  skin,  and  generally  containing  a  horny  or 
calcareous  plate  ;  beneath  this  are  seen  the  re- 
spiratory leaflets  arranged  in  rows  upon  the 
two  sides  of  a  semi-crescentic  membrane  :  their 
structure  in  Aplysia  is  represented  in  Jig.  191. 
Each  branchial  lamella  (a,  a)  divides  dichoto- 
mously  into  smaller  plates  until  the  divisions 
become  extremely  minute;  the  ramifications  of 
the  arteries  and  veins  within  them  being  dis- 
tributed to  each  are  spread  over  an  extent  of 
surface  adequate  to  the  efficient  aeration  of  the 
circulating  fluid  which  they  contain.  The 
principal  trunk  of  the  branchial  artery  (c)  runs 
along  the  concave  margin  of  the  crescentic 
membrane,  while  the  large  venous  trunk  occu- 
pies the  opposite  or  convex  border ;  the  veins 
from  the  branchiae  all  terminate  in  this  great 
vein,  their  orifices  being  disposed  in  circles,  as 
seen  at  d. 

The  Pectinibranchiate  order  includes  that 
large  family  of  aquatic  Gasteropods  which  are 
enclosed  in  shells,  and  the  arrangement  of  the 
whole  of  their  breathing  apparatus  is  adapted 
to  the  respiration  of  w.iter.  The  branchiae  re- 
semble in  structure  those  of  fishes,  and  are  pec- 
tinated or  composed  of  parallel  laminae  disposed 
like  the  beards  of  a  feather,  and  attached  in  two 
or  three  rows  to  the  roof  of  a  large  cavity  placed 
under  the  integuments  of  the  back  ;  or  else  in 
some  rare  cases,  as  in  the  Valvata  cristata,  the 
branchia  is  single,  resembling  a  pen,  and  floats 
externally.*  A  very  material  difference  is  ob- 
servable between  the  truly  aquatic  species  and 
the  pulmonary  Gasteropods  which  inhabit  the 
water,  but  breathe  air ;  in  the  latter,  which  are 
compelled  to  come  to  the  surface  to  respire,  the 
aperture  leading  into  the  pulmonary  cavity  is 
small  and  furnished  with  a  powerful  sphincter, 
so  that  the  air  taken  in  is  retained  at  the  plea- 

*  For  a  figure  of  the  branchial  chamber  of  the 
Buccinum  undatum,  and  an  account  of  the  ciliary 
movements  which  have  been  observed  in  many 
orders  of  Gasteropoda  to  be  connected  with  respi- 
ration, the  reader  is  referred  to  the  article  ClLIA. 


sure  of  the  animal ;  but  in  those  which  are  pro- 
vided with  pectinated  branchiae,  the  entrance  to 
the  branchial  chamber  is  a  wide  fissure,  always 
allowing  free  ingress  and  egress  to  the  circum- 
ambient fluid.  Many  genera  of  this  order  are 
provided  with  a  special  apparatus  called  the  sy- 
phon, for  conveying  the  water  freely  into  the  re- 
spiratory chamber ;  this  is  a  semi-canal  formed 
by  a  fold  of  the  right  side  of  the  mantle,  and 
lodged  in  a  groove  projecting  from  the  mouth 
of  the  shell;  through  this  channel  the  water  at 
all  times  has  free  admission  to  the  gills.  The 
respiratory  organs  of  the  Scutibranchiata  re- 
semble those  of  the  last  order,  and  are  contained 
in  a  similar  cavity,  to  which  the  water  is  con- 
stantly admitted  ;  but  in  the  Cyclobrancltiata 
the  branchiae  consist  of  a  series  of  lamellae 
placed  external  to  the  body,  around  the  border 
of  the  mantle,  by  the  edge  of  which  they  are 
overlapped. 

Respiration  is  effected  in  the  Pulmonary 
Gasteropoda,  whether  they  be  terrestrial  or 
aquatic,  by  an  apparatus  fitted  for  breathing  the 
air  of  the  atmosphere ;  the  lung  or  pulmo-bran- 
chia,  as  we  may  call  this  singular  organ,  con- 
sists of  a  large  cavity  placed  beneath  the  man- 
tle, over  the  surface  of  which  the  vessels  return- 
ing the  blood  from  the  system  spread  in  beau- 
tiful ramifications,  and  from  these  the  pulmo- 
nary veins  take  their  origin,  collecting  the  blood 
which  has  been  exposed  to  the  action  of  the 
air,  and  conveying  it  to  the  heart.  A  large 
orifice  admits  the  air  freely  into  this  chamber, 
the  walls  of  which  alternately  contracting,  draw 
in  and  expel  it  at  regular  intervals  by  an  action 
precisely  similar  to  that  of  the  human  dia- 
phragm. In  the  Slugs  (Limax)  the  cavity  is 
small,  but  the  network  of  the  vessels  spreads 
over  its  whole  surface.  In  the  Snail  (Helix), 
on  the  contrary,  the  organ  is  much  larger,  but 
its  floor  only  is  covered  with  the  respiratory 
ramifications.  In  Jig.  322,  of  the  article  Cir- 
culation, vol.  i.  p.  649,  a  diagram  is  given 
of  this  structure,  and  in  Jig.  190,  (>«,  w,)  the 
details  of  its  arrangement  are  more  minutely 
shewn;  yet  even  in  the  beautiful  drawing 
of  Cuvier,  from  which  our  plate  is  copied, 
the  minute  divisions  of  this  superb  plexus 
are  but  inadequately  shewn.  The  order  which 
has  been  established  by  Ferussac,  under  the 
name  of  Pulmonalia  operculatu,  is  composed 
of  individuals  classed  by  Cuvier  among  the 
Pectinibranchiata,  to  which  in  every  cir- 
cumstance, with  the  exception  of  the  struc- 
ture of  the  respiratory  system,  they  are  closely 
allied ;  these,  however,  breathe  the  air  in  a 
cavity  analogous  to  that  which  we  have  just 
described,  only  differing  in  the  position  and 
nature  of  the  aperture  leading  to  it,  which  here, 
instead  of  being  a  rounded  orifice  in  the  margin 
of  the  collar,  opened  and  closed  at  the  will  of 
the  animal,  is  a  large  fissure  placed  above  the 
head,  exactly  as  in  the  Pectinibranchiate  order. 

Organs  of  circulation. — Having  thus  de- 
scribed the  different  arrangements  of  the 
branchiae,  we  shall  be  enabled  more  readily 
to  investigate  those  modifications  in  the  dis- 
position of  the  organs  subservient  to  the  cir- 
culation of  the  blood  which  are  dependent 
thereupon.    Throughout  the  whole  class,  with 


GASTEROPODA. 
Fig.  190. 


391 


the  exception  of  the  Scutibranchiate  and  some 
of  the  Cyclobranchiate  orders,  the  heart  is 
single,  consisting  of  an  auricular  and  ventri- 
cular cavity,  and  is  interposed  between  the 
branchial  or  pulmonary  vessels  and  the  system, 
receiving  the  aerated  blood  from  the  respiratory 
organs,  and  propelling  it  through  the  body. 
The  heart  of  Aplysia  (fig.  191,  e,  g)  or  of  the 
Snail,  (fig.  190,  o,  p)  will  exemplify  its  ordi- 
nary structure.  The  auricle  varies  slightly  in 
shape  in  different  genera,  but  is  always  ex- 
tremely thin  and  pellucid,  containing  in  its 
coats  muscular  bands  of  great  delicacy.  The 
ventricle  is  provided  with  stronger  walls,  and 
is  generally  separated  from  the  auricle  by  a 
valve,  formed  of  two  pieces.  The  heart  is  en- 
closed in  a  pericardium,  but  its  position  is  re- 
gulated by  that  of  the  branchiae;  and  from  the 
great  diversity  of  arrangement  which  we  have 
found  the  latter  to  present,  a  corresponding 
want  of  uniformity  in  the  locality  which  the 
heart  occupies  may  be  readily  expected.  We 
shall  select  two  forms  of  the  respiratory  organ 
as  examples  of  the  variable  position  of  the 
heart,  and  as  illustrations  of  the  usual  distribu- 
tion of  the  bloodvessels,  viz.  the  Snail,  (vide 
Circulation,  fig.  322,  and  the  Doris,  fig. 
321,)  and  afterwards  notice  the  principal  aber- 
rations from  the  ordinary  disposition.  In  the 
Snail,  the  blood  derived  from  the  whole  body 
is  brought  by  great  veins,  performing  the  func- 


tions both  of  the  vena  cava  and  of  a  pulmonary 
artery,  to  the  plexus  of  vessels  lining  the  floor 
of  the  respiratory  cavity  ;  after  here  undergoing 
the  needful  aeration,  it  enters  the  heart,  from 
whence  it  is  driven  into  the  aorta.  The  aorta 
immediately  divides  into  two  trunks,  one  dis- 
tributed to  the  liver,  the  intestine,  and  the 
ovary;  the  other  supplying  the  stomach,  the 
oral  apparatus,  the  organs  of  generation,  and 
the  foot.  In  the  Slug  the  arteries  are  perfectly 
white  and  opaque,  and  their  ramifications, 
which  may  be  traced  with  great  readiness,  are 
extremely  beautiful. 

In  Doris  (fig.  321)  the  heart  is,  in  conse- 
quence of  the  position  of  the  branchiae  around 
the  anus,  removed  quite  to  the  posterior  extre- 
mity of  the  body.  The  blood  derived  from  all 
parts  of  the  body  is  conducted  by  large  veins 
to  the  respiratory  organs ;  the  pulmonary  arte- 
ries which  return  it  from  thence  unite  into  a 
circular  vessel  (b,  b),  surrounding  the  anus, 
and  from  this  arise  two  vessels,  emptying  them- 
selves into  the  auricle.  The  aorta,  on  issuing 
from  the  heart,  divides  into  two  large  vessels, 
the  first  supplying  the  intestinal  canal,  stomach, 
and  duodenum,  the  organs  of  generation,  the 
foot,  and  the  mouth ;  whilst  the  other  large 
trunk  is  entirely  distributed  to  the  liver. 

In  Tritoniu  the  heart  is  placed  near  the 
centre  of  the  body,  and  the  auiicle  itself  resem- 
bles a  cylindrical  vessel  placed  transversely 


392 


GASTEROPODA. 


across  the  other  viscera,  and  communicating 
with  the  ventricle  near  its  middle.  The  blood 
arrives  at  the  heart  through  four  vessels  from 
the  long  fringe  of  branchiae,  two  comina;  from 
the  anterior  and  two  from  the  posterior  parts. 
We  have  already  described  the  disposition  of 
the  branchiae  in  the  Tectibranchiate  order,  but 
in  following  the  course  of  the  circulating  fluid, 
we  shall  find  in  some  of  the  individuals  in- 
cluded in  this  division  circumstances  requiring 
special  notice,  as  being  of  extreme  interest  to 
the  physiologist.  In  Aplysia,  the  blood  re- 
turned from  the  system  is  brought  by  two  lars;e 
venous  trunks  to  the  vena  cava  or  pulmonary 
artery  (fig.  191,  b);  for  in  this  case  the  same 


Fig.  191. 


vessel  performs  the  functions  of  both ;  these 
large  veins  turn  round  in  the  vicinity  of  the 
operculum,  and  unite  into  one  trunk  prior  to 
their  dispersion  over  the  branchial  plates,  but 
on  opening  them  at  this  point  so  as  to  display 
their  interior,  a  most  singular  arrangement  is 
brought  to  light;  the  sides  of  the  veins  are  found 
to  be  formed  of  muscular  bands  (c)  crossing  each 
other  in  various  directions,  and  leaving  spaces 
between  them  ;  these  intervals  are  seen  even 
by  the  naked  eye  to  be  apertures  establishing  a 
free  communication  between  the  interior  of  the 
vein  and  the  abdominal  cavity,  and  allowing 
injection  to  pass  with  facility  from  the  vein 
into  the  visceral  cavity,  or  from  the  abdomen 
into  the  vein  :  the  anterior  portion  of  each  of 
these  vessels  may  indeed  be  said  to  be  literally 
confounded  with  the  general  cavity  of  the 
the  body,  a  few  muscular  bands,  forming  no 
obstacle  to  a  perfect  communication,  being  the 
only  separation  between  the  two.  It  is  there- 
fore evident  that  the  fluids  contained  in  the 
abdominal  cavity  may  in  this  manner  have 
free  access  to  the  mass  of  the  blood  as  it 
approaches  the  respiratory  organ,  and  that  the 
veins  can  thus  perform  the  office  of  the  ab- 
sorbent system  ;  but  in  what  mariner  the  blood 


is  prevented  from  escaping  through  the  same 
channels  is  not  at  all  obvious,  although  pro- 
bably during  life  the  contraction  of  the  fasci- 
culi which  bound  these  apertures  may  in  some 
measure  obstruct  the  intercourse.  It  is  from 
this  circumstance,  and  the  analogous  commu- 
nication which  exists  in  the  Cephalopoda  by 
the  intervention  of  the  spongy  appendages  to 
the  venaa  cavae  found  in  those  Mollusks,  that 
Cuvier  was  led  to  the  conclusion  that  in  all  the 
class  the  veins  are  the  immediate  agents  of 
absorption,  and  that  an  absorbent  system  does 
not  exist  in  any  but  the  vertebrate  division  of 
the  animal  kingdom.  We  meet,  moreover, 
in  Aplysia  with  another  peculiarity  in  the  cir- 
culating vessels;  the  aorta,  shortly  after  its 
commencement,  divides  into  two  large  arteries 
(A  //'),  one  of  which  presents  nothing  peculiar 
in  its  distribution;  but  to  the  larger  of  the  two, 
whilst  still  enclosed  in  the  pericardium,  we 
find  appended  a  remarkable  structure,  the  use 
of  which  has  been  hitherto  perfectly  inexpli- 
cable :  projecting  from  the  opposite  sides  of 
the  vessel  are  two  vascular  crests,  represented 
in  if  formed  of  a  plexus  of  vessels  issuing 
from  the  aorta  itself,  and  ramifying  in  an  ex- 
ceedingly beautiful  manner  through  the  sub- 
stance of  these  extraordinary  organs  ;  in  other 
respects  the  arteries  are  distributed  in  the  usual 
manner.  The  Cyclobranchiate  and  Scutibran- 
chiate  Gasteropods  approximate  the  testaceous 
class  in  many  points  of  their  organization,  but 
in  none  more  so  than  in  the  position  which  the 
heart  is  found  to  occupy,  and  the  arrangement 
of  its  cavities.  In  Patella,  indeed,  the  heart 
is  placed  in  the  anterior  part  of  the  body,  and 
still  conforms  in  its  general  structure  to  the 
description  which  we  have  given  above  ;  but 
in  Oscabrio  the  auricle  is  divided  into  two 
distinct  portions,  one  receiving  the  blood  from 
each  range  of  branchial  plates  ;  and  in  Haliotis, 
Fissurclla,  Emargenula,  and  Parmophorus,  not 
only  is  this  division  of  the  auricle  met  with, 
but  the  ventricle,  as  in  many  of  the  testaceous 
Mollusks,  is  perforated  by  the  rectum,  and 
the  similarity  of  arrangement  which  is  here 
presented  with  what  is  met  with  in  the  Con- 
chifera  will  be  readily  appreciated  by  a  refer- 
ence to  the  article  which  treats  of  the  anatomy 
of  that  division  of  the  Mollusca. 

Nervous  system. — The  nervous  system  of 
the  Gasteropoda  furnishes  us  with  the  most 
perfect  form  of  the  heterogangliate,  or  as  it  has 
been lesshappily  denominated,  cyclo-gangliated 
type.  It  consists  of  a  variable  number  of 
ganglia  or  nervous  centres  disposed  in  different 
parts  of  the  body,  but  connected  with  each 
other  by  cords  of  communication,  and  from 
these  ganglia  the  nerves  appropriated  to  dif- 
ferent parts  proceed.  Each  ganglion,  therefore, 
is  a  distinct  brain;  and  were  the  preponderance 
in  size  to  be  regarded  as  the  criterion  of  rela- 
tive importance,  it  would  not  unfrequently  be 
hard  to  say  to  which  the  pre-eminence  is  due. 
There  is,  however,  as  we  shall  soon  perceive, 
an  uniformity  in  the  arrangement  of  certain 
masses,  and  a  regularity  in  the  appropriation 
of  the  nerves  proceeding  from  them  to  parti- 
cular organs,  which  leave  us  little  room  for 


GASTEROPODA. 


393 


hesitation  upon  this  point ;  before,  however, 
entering  upon  a  more  detailed  account,  we 
will  offer  a  few  general  observations  upon  this 
system,  applicable  to  the  whole  class.  The 
nervous  centres  are  obviously  of  a  different 
nature  from  the  cords  by  means  of  which  they 
are  connected  into  one  system,  and  from  the 
nerves  arising  from  them  ;  the  nervous  mass 
of  the  ganglion  itself  is  generally  granular  in 
its  appearance,  whilst  the  texture  of  the  nerves 
is  homogeneous  and  smooth  ;  the  distinction 
is,  however,  in  a  few  instances,  rendered  still 
more  remarkable  by  a  striking  difference  in 
colour ;  thus  in  Aplysia,  whilst  the  nerves  are 
of  a  pure  white,  the  ganglionic  centres  are  of 
a  beautiful  red  tint;  the  same  circumstance  is 
met  with  in  the  Bulimus  Stagna'is,  and  has 
also  been  remarked  in  many  of  the  conchi- 
ferous  Mollusca.  A  second  peculiarity  may 
be  noticed  in  the  mode  in  which  the  nerves 
and  ganglia  are  invested  with  a  neurilema  or 
sheath,  so  loosely  connected  with  them  that  it 
may  be  inflated  or  injected  with  great  facility, 
and  for  this  reason  the  nerves  have  been  mis- 
taken for  vessels  by  some  authors. 

As  an  example  of  the  most  perfectly  dis- 
persed arrangement  of  the  nervous  centres  we 
shall  select  Aplysia,  in  which  the  ganglia  are 
more  numerous  than  in  the  generality  of  the 
Gasteropod  Mollusks.  In  this  animal  we  find 
a  ganglion  placed  above  the  cesophagus  to 
which  the  name  of  the  brain  is  universally 
allowed,  not  so  much  on  account  of  its  size 
as  because  throughout  the  class  it  constantly 
occupies  the  same  position,  and  as  invariably 
supplies  those  nerves  which  are  distributed  to 
the  most  important  organs  of  sense  ;  in  this 
case  its  branches  run  to  the  muscles  of  the 
head  and  to  the  male  organ  of  generation ;  it 
likewise  sends  on  either  side  a  large  branch  to 
each  of  the  great  tentacles,  which  as  they 
approach  those  organs  give  origin  to  the  optic 
nerves. 

On  each  side  of  the  cesophagus  is  found 
another  ganglion  equalling  the  brain  in  size, 
and  constituting  two  other  nervous  centres, 
which  are  united  to  each  other  and  to  the  brain 
by  cords  so  disposed  as  to  form  a  collar  around 
the  cesophagus;  each  of  these  gives  off  a 
number  of  nervous  filaments,  which  are  lost 
in  the  muscular  envelope  of  the  body ;  a 
fourth  ganglion  joined  to  the  brain  by  two 
cords  is  found  under  the  fleshy  mass  of  the 
mouth ;  this  supplies  the  cesophagus,  the 
muscles  of  the  mouth,  and  the  salivary  glands. 
At  a  considerable  distance  from  these,  and 
placed  near  the  posterior  portion  of  the  body 
in  the  vicinity  of  the  female  generative  organs 
and  the  respiratory  apparatus,  is  a  fifth  gan- 
glion communicating  with  the  second  and  third 
by  means  of  two  long  nerves,  and  giving 
branches  to  the  liver,  the  alimentary  canal, 
the  female  generative  system,  as  also  to  the 
branchiae  and  the  muscles  of  the  operculum. 
From  this  account  it  will  be  seen  that  none  of 
these  ganglia  can  be  said  to  preside  exclusively 
over  any  particular  apparatus,  branches  from 
each  being  distributed  to  very  different  struc- 
tures ;  but  yet,  speaking  generally,  there  ap- 

vor,.  ii. 


pears  to  be  some  reason  for  classifying  their 
functions.  Thus  the  brain  is  exclusively  the 
centre  of  the  principal  senses :  the  two  great 
lateral  ganglia  supply  the  bulk  of  the  muscu- 
lar system  ;  the  sub-oral  ganglion  is  particularly 
subservient  to  mastication  and  deglutition,  and 
the  fifth  or  posterior  nucleus  being  almost 
entirely  appropriated  to  the  supply  of  the 
digestive,  respiratory,  circulatory,  and  gene- 
rative viscera,  might  be  regarded  as  analogous 
to  the  sympathetic.  There  are,  however,  but 
few  of  the  Gasteropoda  in  which  the  ganglia 
are  so  distinct  in  position  and  function  as  in 
Aplysia.  In  the  inoperculate  pulmonary  Gas- 
teropods,  as  in  the  Snail  and  Slug,  the  nervous 
centres  are  only  two  in  number,  namely,  the 
brain,  placed  in  its  usual  position  above  the 
cesophagus,  and  a  large  sub-cesophageal  gan- 
glion connected  with  it  by  two  cords  embracing 
the  oesophageal  tube.  The  brain  in  this  case 
supplies  nerves  to  the  muscles  of  the  mouth 
and  lips,  as  well  as  to  the  skin  in  their  vici- 
nity ;  it  likewise  furnishes  the  nerves  of  touch 
and  of  vision,  besides  those  distributed  to  the 
generative  organs,  and  from  the  sub-cesopha- 
geal ganglion,  which  fully  equals  the  brain  in 
size,  arise  those  nerves  which  supply  the 
muscles  of  the  body  and  the  viscera.  There  is, 
however,  placed  under  the  cesophagus  a  very 
minute  nervous  mass,  which  from  the  con- 
stancy of  its  occurrence  is  worthy  of  notice ; 
it  is  formed  by  the  union  of  two  minute  nerves 
arising  from  the  brain,  and  the  little  filaments 
which  it  gives  off  are  lost  in  the  cesophagus 
itself. 

One  remarkable  circumstance  may  be  men- 
tioned as  being  probably  peculiar  to  the  class 
under  consideration,  namely,  the  changes  of 
position  to  which  their  nervous  centres  are 
subject ;  obeying  the  movements  of  the  mass 
of  the  mouth,  with  which  they  are  inti- 
mately connected,  they  are  pulled  backwards 
and  forwards  by  the  muscles  serving  for  the 
protrusion  and  retraction  of  the  oral  appa- 
ratus, and  are  thus  constantly  changing  their 
relations  with  the  surrounding  parts.  In  the 
Snail  it  would  seem  that  the  great  size  of  the 
nervous  collar  which  embraces  the  cesophagus 
will  in  some  circumstances  permit  the  mass 
of  the  mouth  to  pass  entirely  through  it,  so 
that  sometimes  the  brain  rests  upon  the  oeso- 
phagus, and  at  others  is  placed  upon  the  in- 
verted lips. 

In  most  of  the  Pectinibranchiata,  the  brain 
consists  of  two  ganglia  united  by  a  transverse 
cord  ;  from  these  two  centres  arise  the  principal 
nerves,  two  of  which  unite  to  form  a  small 
ganglion  beneath  the  cesophagus,  from  which 
that  tube  derives  its  peculiar  supply. 

It  is  in  the  Nudibranchiate  division,  how- 
ever, that  the  nervous  centres  exist  in  their 
most  concentrated  form,  and  in  these  it  is 
doubtful  whether  there  are  any  ganglia,  except 
the  large  supra-cesophageal  brain.  We  may 
take  Tritonia  as  an  example  of  this  form  of  the 
nervous  system.  In  this  beautiful  Gasteropod 
the  brain  consists  of  four  tubercles  placed 
across  the  commencement  of  the  cesophagus, 
the  nervous  collar  being  completed  by  a  simple 

2  D 


394 


GASTEROPODA. 


cord;  all  the  nerves  which  supply  the  skin, 
the  muscular  integument,  the  tentacles,  the 
eye,  and  the  muscles  of  the  mouth  arise  from 
the  brain,  and  anatomists  have  not  hitherto 
detected  any  other  source  of  nervous  supply, 
although  Cuvier  suspected  two  minute  bodies, 
which  he  found  beneath  the  oesophagus  appa- 
rently connected  with  the  brain,  to  be  of  a 
ganglionic  nature. 

The  slow-moving  and  repent  tribes  of  which 
we  are  now  speaking  have  their  powers  of  sense 
almost  entirely  limited  to  the  perception  of 
objects  in  actual  contact  with  their  bodies, 
and  instruments  adapted  to  touch  and  vision 
are  the  only  organs  of  sense  which  the  anato- 
mist has  been  able  to  distinguish.  The  utter 
want  of  an  internal  skeleton  or  of  an  external  ar- 
ticulated crust  forbids  us  to  expect  that  any  of 
them  are  provided  with  an  apparatus  specially 
calculated  to  appreciate  sonorous  undulations. 
Their  tongue,  coated  as  it  is  with  horny  plates, 
studded  with  spines,  or  absolutely  corneous  in 
texture,  is  obviously  rather  an  instrument  of 
deglutition  than  an  organ  of  taste.  No  re- 
searches have  hitherto  detected  any  part  of  the 
body  which  could  be  looked  upon  as  devoted 
to  smell ;  the  eye  is  generally  a  mere  point, 
rather  inferred  to  be  such  by  analogy  than 
clearly  adapted  to  vision;  and  the  sense  of 
touch  in  fact  is  the  only  one  which  anatomical 
evidence  would  intimate  to  be  perfectly  deve- 
loped. Yet  in  spite  of  these  apparent  defi- 
ciencies, observation  teaches  us  that  many  genera 
are  not  utterly  deprived  of  the  power  of  appre- 
ciating intimations  from  without  connected  with 
the  perception  of  odours ;  it  has  been  found 
by  direct  experiment  that  some  of  them  are  pe- 
culiarly sensible  of  the  approach  of  scented 
bodies  ;  thus  the  snail,  although  at  rest  within 
the  shelly  covering  which  forms  its  habitation, 
will  with  great  quickness  perceive  the  proximity 
of  scented  plants  which  are  agreeable  articles  of 
food,  and  promptly  issue  from  its  concealment 
to  devour  them.  Some  anatomists  have  sup- 
posed that  it  is  at  the  entrance  of  the  respiratory 
cavity  that  we  are  to  look  for  the  special  seat  of 
smell,  where,  as  the  air  alternately  enters  and  is 
expelled  by  the  movements  of  respiration,  the 
odorous  particles  with  which  it  may  be  impreg- 
nated are  rendered  sensible.  Others  with 
scarcely  less  probability  conceive  that  the  whole 
surface  of  the  body  which  is  exposed  to  the  at- 
mosphere may  be  endowed  with  a  power  of 
smelling,  the  quantity  of  nerves  which  are  dis- 
tributed to  the  integument,  and  the  moisture 
with  which  it  is  constantly  lubricated,  seeming 
to  adapt  it  perfectly  to  the  performance  of  this 
function,  giving  it  all  the  characters  of  a 
Schneiderian  membrane.  It  is  not  impossible 
that  sounds  may  be  perceived  in  a  somewhat 
analogous  manner,  although  no  proof  has  yet 
been  adduced  that  any  of  the  Gasteropoda  are 
sensible  to  impressions  of  this  nature.  The 
sense  of  touch  is  exquisitely  delicate  over  the 
whole  surface  of  the  animal,  but  more  especially 
so  in  the  foot,  which  is  extremely  vascular  and 
abundantly  supplied  with  nerves  ;  yet  in  spite 
of  this  delicacy  in  the  organisation  of  the  skin 
which  makes  it  so  sensible  of  contact,  it  appears 


to  have  been  beneficently  ordered  that  animals 
so  helpless  and  exposed  to  injury  from  every 
quarter,  are  but  little  sensible  to  pain,  and  that 
such  is  the  case,  M.  Ferussac,  a  diligent  ob- 
server of  their  economy,  bears  ample  testimony. 
"  I  have  seen,"  says  he,  "  the  terrestrial  gaste- 
ropods  allow  their  skin  to  be  eaten  by  others, 
and  in  spite  of  large  wounds  thus  produced, 
shew  no  sign  of  pain."  But  besides  the  sen- 
sation generally  distributed  over  the  skin,  we 
may  observe  in  most  instances  organs  of  variable 
form  which  seem  peculiarly  appropriated  to 
touch.  These  are  the  tentacles,  or  horns  as 
they  are  usually  termed,  which  occupy  a  va- 
riable position  upon  the  anterior  part  of  the 
animal. 

The  tentacles  vary  in  number  in  different 
genera :  thus  in  Flanorbis  we  find  two,  in  the 
generality  of  cases  four;  in  a  few,  as  some  spe- 
cies of  (Eolis,  six ;  and  in  Polycera  even  eight  of 
these  appendages  are  met  with.  The  structure 
of  the  tentacles  is  by  no  means  the  same  in  all 
the  individuals  belonging  to  this  class.  In  the 
aquatic  species  they  are  to  a  greater  or  less  ex- 
tent retractile,  but  can  in  no  case  be  entirely 
concealed  within  the  body,  as  is  usual  in  the 
terrestrial  division  ;  they  are  therefore  not  hol- 
low, but  composed  of  various  strata  of  circular, 
oblique,  and  longitudinal  muscular  fibres,  by 
means  of  which  they  are  moved  in  every  direc- 
tion, and  applied  with  facility  to  the  objects 
submitted  to  their  examination.  In  all  instances 
they  are  plentifully  supplied  with  nerves 
arising  immediately  from  the  brain.  Their 
shape  is  subject  to  great  variation ;  they  are 
usually  simple  processes  from  the  surface  of  the 
body  more  or  less  elongated,  and  in  some  cases 
even  filiform,  as  in  Planorbis.  In  Murex 
(Jig.  193)  each  tentacle  is  a  thick  and  fleshy 
stem,  near  the  extremity  of  which  a  smaller  one 
is  appended.  In  Tritonia  each  tentacle  is  com- 
posed of  five  feathery  leaflets,  and  is  enclosed 
in  a  kind  of  sheath  which  surrounds  its  base. 
In  Doris  the  two  inferior  are  broad,  flat,  and 
fleshy,  while  the  superior  are  thick  and  club- 
shaped.  In  Scyllaa  they  consist  of  broad 
fleshy  expansions  attached  by  thin  pedicles  to 
the  anterior  part  of  the  body.  In  Thethys 
they  are  placed  at  the  base  of  the  veil  which 
characterises  the  animal,  but  in  all  cases  they 
are  solid  and  incapable  of  entire  retraction.  In 
the  terrestrial  Gasteropoda,  in  which  from  many 
causes  the  tentacles  are  more  exposed  to  injury, 
a  much  more  complicated  structure  is  needed, 
by  which  these  important  organs  are  not  only 
moved  with  facility  in  different  directions,  but 
which  allows  them  to  be  perfectly  withdrawn 
into  the  interior  of  the  body,  from  which  posi- 
tion they  may  be  made  to  emerge  at  the  will  of 
the  animal :  the  mechanism  by  which  this  is 
effected  will  be  understood  by  referring  to  Jig. 
192,  representing  a  dissection  of  the  common 
snail,  and  exhibiting  the  tentacles  in  different 
states  of  protrusion.  Each  tentacle  (c,  d,)  is  here 
seen  to  be  a  hollow  tube,  the  walls  of  which  are 
composed  of  circular  bands  of  muscle,  and 
capable  of  being  inverted  like  the  finger  of  a 
glove;  it  is  in  fact,  when  not  in  use,  drawn  with- 
in itself  by  an  extremely  simple  arrangement, 


GASTEROPODA. 


395 


Fig.  192. 


Structure  of  the  tentacle!  in  the  Garden-Snail 
(  Helix  Pomatia ). 

From  the  common  retractor  muscles  of  the 
foot  four  long  muscular  slips  are  detached, 
one  for  each  horn  ;  these  run  in  company  with 
the  nerve  to  each  tentacle,  passing  within  its 
tube  when  protruded,  quite  to  the  extremity 
(g).  The  contraction  of  this  muscle  dragging 
the  apex  of  the  organ  inwards,  as  seen  at  c,  of 
course  causes  its  complete  inversion,  whilst  its 
protrusion  is  effected  by  the  alternate  contrac- 
tions of  the  circular  bands  of  muscle  of  which 
the  walls  of  each  tentacle  are  composed.  There 
is,  however,  another  peculiarity  rendered  neces- 
sary by  this  singular  mechanism,  by  which  the 
nerves  supplying  the  sense  of  touch  may  be 
enabled  to  accommodate  themselves  to  such 
sudden  and  extensive  changes  of  position  ;  for 
this  purpose  the  nerves  supplying  these  organs 
are  of  great  length,  reaching  with  facility  to  the 
end  of  the  tubes  when  protruded,  and  in  their 
retracted  state  the  nerves  are  seen  folded  up 
within  the  body  in  large  convolutions.  In  the 
figure,  a  a  indicates  the  origins  of  the  retractor 
muscles  of  the  foot  from  the  columella;  b,  the 
right  superior  tentacle  fully  protruded ;  c,  the 
left  superior  tentacle  partially  retracted  ;  d,  the 
left  inferior  tentacle  extended,  and  e,  the  right 
inferior  tentacle  fully  retracted  and  concealed 
within  the  body ;  f\  the  nerve  supplying  the 
superior  tentacle  elongated  by  its  extension  ; 
g,  the  retractor  muscle  of  the  same  tentacle 
arising  from  the  common  retractor  muscle  of 
the  foot  and  inserted  into  the  extremity  of  the 
tube  ;  /),  the  nerve  of  the  opposite  side  thrown 
into  folds  ;  i,  the  retractor  muscle  of  the  same 
tentacle  contracted  ;  k,  the  aperture  through 
which  the  nerve  and  retractor  muscle  enter  the 
tentacle  d  ;  I,  the  brain  ;  m,  the  subcesophageal 
ganglion  ;  n,  the  eye. 

Vision. — The  eyes  of  Gasteropoda  are  ex- 
tremely small  in  comparison  with  the  bulk  of 
the  animals,  and  seem  more  to  represent  the 
rudiments  of  an  organ  of  sight  than  to  be 
adapted  to  distinct  vision.  In  many  species 
indeed  they  appear  to  be  absolutely  wanting. 
When  found,  they  resemble  minute  black  points, 


by  far  too  email  to  admit  of  any  satisfactory 
examination  of  their  internal  structure;  and  even 
in  the  largest  forms  of  the  organ  which  are  met 
with  in  the  more  bulky  marine  genera,  it  is  with 
difficulty  that  their  organisation  can  be  explored. 
In  Jig.  193  we  have  delineated  the  position 
and  structure  of  the  eye  in  a  large  Murex. 

Fig.  193. 


Tentacles  and  eye  of  Murex. 

The  natural  size  of  the  organ  is  seen  in  the 
upper  figure,  in  which  on  the  right  side  the  organ 
is  represented  untouched,  while  on  the  left  a 
section  has  been  made  to  exhibit  its  interior. 
This  section  when  magnified,  as  in  the  lower 
figure,  shews  us  that  it  consists  of  a  spherical 
cavity  lined  posteriorly  with  a  dark  choroidal 
membrane, and  containing  a  large  spherical  lens ; 
the  position  and  structure  of  the  retina  we  have 
been  unable  satisfactorily  to  determine,  although 
the  visual  nerve  may  be  readily  traced  to  the 
back  of  the  choroid,  where  it  seems  to  expand ; 
but  whether,  as  in  the  Cephalopods,  its  sentient 
portion  is  spread  out  behind  the  pigment 
which  lines  the  eye-ball,  or  whether,  as  in  the 
forms  of  the  organ  common  to  the  vertebrate 
orders,  the  retina  is  placed  anterior  to  the 
choroid,  is  a  question  which  we  are  at  present 
unable  to  solve.  But  however  this  may  be,  we 
see  anteriorly  a  distinct  pupil  surrounded  by  a 
dark  radiating  zone,  apparently  an  iris,  to  which 
it  corresponds  at  least  in  position,  although 
that  it  is  really  capable  of  contracting  or  en- 
larging the  pupillary  aperture  is  more  than  our 
observations  warrant  us  in  affirming.  Finding, 
therefore,  the  eye  of  the  Murex  to  offer  a  struc- 
ture which  indubitably  entitles  it  to  be  regarded 
as  an  organ  of  sight,  we  are  justified  in  consi- 
dering the  more  minute  specks  of  smaller  Gas- 
teropoda as  similarly  formed  and  subservient  to 
the  same  office.  In  the  aquatic  species  the 
eyes  are  generally  placed  at  the  base  of  the  su- 
perior or  larger  tentacles,  although  not  unfre- 
quently  they  are  supported  upon  short  pedicles 
appropriated  to  them,  as  is  the  case  in  Haliotis 
and  others.  In  Murex  we  have  seen  that  the 
tentacles  which  support  them  are  large  and 

2  d  2 


396 


GASTEROPODA. 


fleshy,  and  by  the  position  of  the  eyes  at  the 
extremity  of  so  long  a  stem  these  can  be  readily 
directed  to  different  objects.  In  no  case,  how- 
ever, can  they  be  retracted  within  the  body  so 
as  to  be  quite  enclosed  in  the  visceral  cavity.  In 
the  terrestrial  Gasteropods  the  eyes  are  gene- 
rally placed  at  the  extremity  of  the  superior 
horns,  a  position  which  manifestly  extends  the 
range  of  vision,  and  moreover,  in  consequence 
of  the  structure  which  we  have  described  when 
speaking  of  the  organs  of  touch,  may  be  com- 
pletely drawn  within  the  body.  In  jig.  189,  b, 
the  eye  of  Vaginulus  is  seen  at  the  extremity  of 
the  upper  tentacle,  and  the  origin  of  the  optic 
nerve  (c )  from  the  brain  (d),  as  well  as  the 
convolutions  which  it  makes  to  allow  of  its 
adaptation  to  the  varying  length  of  the  tentacle, 
and  the  bulb  in  which  it  terminates  behind  the 
eyeball  (b*),  are  sufficiently  displayed.  In  Jig. 
192,  b,  the  eye  of  the  snail  exhibiting  the  same 
circumstances  has  been  represented,  and  the 
apparatus  by  which  the  movements  of  the  whole 
organ  are  effected  is  so  clearly  shewn  as  to 
render  further  description  superfluous. 

Generative  system. — The  description  of  the 
generative  apparatus  of  the  Gasteropoda  forms 
one  of  the  most  remarkable  parts  of  their 
history,  and  the  complication  which  it  presents 
in  some  orders  is  probably  unique  in  the  ani- 
mal kingdom.  The  class  may  be  divided,  as 
far  as  relates  to  this  function,  into  three  great 
divisions: — 1st.  Hermaphrodite  and  self-im- 
pregnating; 2d.  Hermaphrodite,  but  recipro- 
cally impregnating  each  other  by  mutual 
copulation  ;  3d.  Sexes  distinct,  the  female 
being  impregnated  by  copulation  with  the 
male.  We  shall  consider  each  of  these  divi- 
sions in  the  order  in  which  they  have  been 
enumerated.  The  lowest  orders  approximate 
the  Conchifera  in  most  parts  of  their  organisa- 
tion, and  in  the  arrangement  of  their  generative 
system  we  need  not  be  surprised  to  see  a 
manifest  resemblance.  The  Scutibr  uncinate 
and  Cyclobranchiate  orders,  therefore,  present 
this  great  distinguishing  character,  which  more 
than  any  other  detaches  them  from  the  others, 
namely,  that  every  individual  being  furnished 
both  with  ovigerous  and  impregnating  organs 
is  sufficient  to  the  impregnation  of  its  own 
ova.  Nothing,  in  truth,  can  be  more  simple 
than  such  an  arrangement.  The  ovary  is  found, 
■when  empty,  embedded  in  the  substance  of 
the  liver,  but  at  certain  epochs  it  becomes  so 
much  distended  with  ova  as  to  cover  in  great 
part  the  rest  of  the  viscera ;  from  this  ovary 
arises  a  simple  canal  or  oviduct,  which  termi- 
nates after  a  short  course  in  the  neighbourhood 
of  the  anus.  No  trace  of  accessory  apparatus 
has  been  found,  and  the  only  part  to  which 
the  office  of  a  testis  is  assignable  is  the  tube 
through  which  the  ova  are  discharged,  which 
probably  furnishes  a  secretion  subservient  to 
the  impregnation  of  the  eggs.  Such  is  the 
structure  of  the  generative  system  in  Haliotis, 
Patella,  and  others  of  the  orders  to  which 
these  respectively  belong,  exhibiting  a  simpli- 
city of  parts  widely  different  from  what  is 
found  in  the  division  which  next  presents  itself 
to  our  notice.    The  second  type  of  the  genera- 


tive apparatus  is  common  to  the  Nudibran- 

chiute,  Infer  abranchiate,  Tectibranchiate,  and 
Inoperculated pulmonary  orders ;  in  all  of  which 
every  individual  is  provided  with  both  male  and 
female  organs  of  copulation,  and,  accordingly, 
mutual  impregnation  is  effected  by  the  congress 
of  two  individuals,  or  in  a  few  instances  by 
the  combination  of  several.  We  shall  select 
the  common  snail  ( Helix pomatia)  as  the  most 
familiar  illustration  of  the  general  arrangement 
of  the  parts  composing  this  double  apparatus, 
leaving  the  varieties  which  it  presents  to  sub- 
sequent notice.  The  admirable  plate  of  Cuvier, 
of  which  Jig.  190  is  a  copy,  represents  the 
whole  system  with  that  clearness  and  fidelity 
so  characteristic  of  all  the  laborious  contribu- 
tions to  science  which  we  owe  to  his  indefati- 
gable industry.  The  female  portion  consists 
of  the  ovary,  the  oviduct,  and  an  enlarged 
portion  of  the  oviduct  which  forms  a  receptacle 
for  the  ova,  and  is  called  by  Cuvier  the  womb 
(la  matrice).  The  ovary  (q)  is  a  racemose 
mass  embedded  in  that  portion  of  the  liver 
which  is  enclosed  in  the  last  spire  of  the  body, 
i.  e.  that  part  which  is  placed  nearest  to  the 
apex  of  the  shell ;  from  this  proceeds  a  slender 
oviduct  (r),  folded  in  zigzag  curves,  and  vari- 
ously convoluted  :  it  commences  by  many 
small  branches  derived  from  the  ovary,  and 
terminates  in  a  mass  (s),  regarded  by  Cuvier 
as  the  testis,  in  which  it  becomes  so  attenuated 
that  it  is  difficult  to  trace  it ;  emerging,  how- 
ever, from  this  mass,  it  expands  into  the 
womb  (t),  which  is  a  long,  capacious,  and 
sacculated  canal,  and  capable  of  much  dis- 
tension, in  which  the  eggs  are  retained  until 
they  have  acquired  their  full  development : 
this  viscus  opens  into  the  common  generative 
cavity  at  e,  Jig.  194. 

The  male  organs  consist  of  a  testicle,  vas 
deferens,  and  penis.  The  testicle  (s,  Jig. 190) 
appears  to  be  composed  of  two  distinct  portions, 
the  larger  of  which  is  soft  and  homogeneous  in 
texture,  but  the  smaller  has  a  granulated  ap- 
pearance ;  the  latter  (m)  runs  along  the  womb 
like  a  mesentery,  connecting  its  folds  as  far  as 
the  termination  of  that  viscus.  The  testicle 
varies  much  in  size  at  different  periods,  being 
generally  very  small,  but  during  the  season  of 
love  it  dilates  so  as  to  fill  nearly  half  of  the 
viscera]  cavity,  at  which  time  the  womb  like- 
wise is  much  enlarged.  From  the  testicle 
arises  its  vas  deferens  or  excretory  duct,  which 
terminates  in  the  penis  near  the  base  of  that 
organ.  The  penis  (fig.  194,  n)  is  a  most  sin- 
gular instrument,  resembling  a  long  hollow 
whip-lash,  formed  of  circular  fibres,  and,  like 
the  tentacles,  capable  of  complete  inversion, 
which  in  fact  occurs  whenever  it  is  protruded 
from  the  body ;  it  is  also  furnished  with  a  re- 
tractor muscle  (Jig.  190,  w ),  serving  to  draw  it 
back  again  after  copulation  is  accomplished. 
The  penis  is  not  perforated  at  its  extremity, 
but  the  vas  deferens  terminates  within  it  by  a 
small  aperture,  which  of  course  during  the 
inversion  of  the  organ  opens  externally  at 
about  one-third  of  the  length  of  the  penis  from 
its  root ;  the  aperture  by  which  the  vas  defe- 
rens thus  opens  upon  the  exterior  of  the  penis, 


GASTEROPODA. 


397 


when  that  organ  is  protruded,  is  sufficiently 
distinct,  admitting  with  facility  an  ordinary 
bristle  (fig.  194,  I).  On  slitting  up  the  penis 
as  it  usually  lies  retracted  into  the  visceral 
cavity,  its  inner  membrane  is  found  gathered 
into  longitudinal  folds,  and  this  provision  is 
needful  to  allow  of  that  distension  which  must 
occur  during  its  erection,  at  which  time  this 
lining  membrane  becomes  the  external  integu- 
ment of  the  protruded  organ. 

These  parts  would  seem  sufficient  in  them- 
selves to  fulfil  the  functions  belonging  to  the 
organs  of  both  sexes,  nevertheless  we  find 
others  superadded,  the  uses  of  which  are  not 
so  readily  assignable ;  these  are  the  bladder, 
as  it  is  called  by  Cuvier,  the  multifid  vesicles, 
and  the  sac  of  the  dart. 

The  sac  which  has  been  called  the  bladder 
(fig.  190,  z,  fg.  194,  o)  is  invariably  present; 
it  consists  of  a  round  vesicle,  variable  in  size, 
communicating  by  means  of  a  canal,  generally 
of  considerable  length  and  diameter,  with  the 
termination  of  the  matrix  :  it  is  usually  found 
filled  with  a  thick  and  viscid  brownish  matter, 
and  is  generally  supposed  to  furnish  an  enve- 
lope to  the  eggs  as  they  escape  from  the  con- 
voluted oviduct,  an  opinion,  however,  as  we 
shall  afterwards  see,  which  is  not  without  op- 
ponents. 

The  multifid  vesicles  (fig.  190,  x,  fig.  194, 
c )  are  much  less  constantly  met  with,  and  are 
in  fact  almost  peculiar  to  the  snail ;  they  are 
two  groups  of  cceca,  each  composed  of  about 
thirty  blind  tubes,  which  after  uniting  into 
larger  canals  ultimately  form  a  principal  duct 
on  each  side,  through  which  the  secretion 
which  they  furnish  is  poured  at  a  little  distance 
below  the  orifice  leading  to  the  bladder  into 
the  passage  by  which  the  ova  are  expelled. 
The  fluid  furnished  by  these  curious  glandular 
appendages  is  white  and  milky,  but  as  this 
secretion  is  almost  peculiar  to  the  genus  Helir, 
its  use  is  extremely  problematic. 

The  sac  if  the  dart  (fig.  190,  y,  fig.  194,  b) 
is  another  part  of  the  generative  apparatus  only 
found  in  the  snail,  and  from  the  extraordinary 
instrument  which  it  conceals  is  perhaps  the 
most  singular  appendage  to  the  generative  sys- 
tem met  with  in  any  class  of  animals.  It  is 
an  oblong  sac  with  strong  muscular  walls 
opening  by  a  special  aperture  into  the  common 
generative  cavity,  like  which  it  is  capable  of 
complete  inversion.  On  opening  it,  its  cavity 
is  seen  to  be  quadrangular,  and  at  its  bottom 
projects  a  four-sided  fleshy  tubercle,  which 
secretes  the  curious  weapon  that  this  sac  is 
destined  to  conceal.  This  (fig.  194,  b )  con- 
sists of  a  four-sided  calcareous  and  apparently 
crystalline  spike,  about  five  lines  in  length, 
which  grows  by  successive  layers  deposited  at 
its  base  from  the  surface  of  the  fleshy  tubercle 
to  which  it  is  attached  :  it  will  be  evident  that 
when  the  sac  is  everted,  the  dart  contained 
within  it  will  be  protruded  externally.  This 
dart,  if  broken  off  from  its  place  of  attachment, 
is  speedily  renewed. 

To  complete  our  description  of  the  parts 
composing  this  complex  organisation,  it  remains 
only  to  mention  the  common  generative  cavity 


Generative  organs  of  Helix  Pomatia. 

(fig.  194,  a ),  into  which  the  others  open ;  this, 
when  in  its  ordinary  position,  is  a  muscular 
bag,  opening  externally  by  a  large  aperture 
near  the  upper  tentacle  on  the  right  side  of  the 
neck,  whilst  at  its  bottom  are  seen  the  orifices 
of  three  distinct  passages,  one  leading  to  the 
penis,  one  to  the  female  organs,  and  a  third 
to  the  sac  of  the  dart.  This  cavity,  like  that 
of  the  dart,  is  capable  of  inversion,  which  is 
effected  partly  by  the  action  of  its  muscular 
walls,  aided  in  all  probability  by  a  kind  of 
temporary  erection,  and  when  thus  turned  in- 
side out,  the  orifices  leading  to  the  penis,  the 
womb,  and  the  sac  of  the  dart  of  course 
become  external. 

In  order  to  understand  the  functions  of  these 
various  parts  it  will  be  necessary  to  describe  at 
length  the  singular  mode  in  which  copulation 
is  effected.  When  two  snails,  amorously  dis- 
posed, approach  each  other,  they  begin  their 
blandishments  by  rubbing  the  surfaces  of  their 
bodies  together,  touching  successively  every 
part.  This  preliminary  testimony  of  affection 
lasts  for  several  hours,  gradually  exciting  the 
animals  to  more  effective  demonstrations.  At 
the  end  of  this  time  the  generative  orifice, 
placed  on  the  right  side  of  the  neck,  is 
seen  to  dilate,  and  the  common  generative 
cavity  becoming  gradually  inverted  displays  ex- 
ternally the  three  apertures  which  open  into  it. 
This  being  effected,  an  encounter  of  a  truly 
unique  character  commences;  the  opening- 
leading  to  the  sac  of  the  dart  next  expands, 
and  that  organ  undergoing  a  similar  inversion 
displays  the  dart  affixed  to  its  bottom.  A 
series  of  manoeuvres  may  then  be  witnessed  of 
an  unaccountable  description ;  each  snail,  in 
turn,  inspired  with  an  alacrity  perfectly  foreign 
to  its  ordinary  sluggish  movements,  striving 
with  his  dart  to  prick  the  body  of  his  associate, 
which  with  equal  promptitude  endeavours  to 


398 


GASTEROPODA. 


avoid  the  wound,  retreating  into  his  shell,  and 
performing  a  variety  of  evolutions  to  get  out  of 
reach.  At  length,  however,  the  assailant  suc- 
ceeds, and  strikes  the  point  of  his  weapon 
into  the  skin  of  his  paramour  at  any  vulnerable 
point  which  may  be  found.  The  dart  is  gene- 
rally broken  off  by  this  encounter,  sometimes 
sticking  in  the  skin,  but  more  frequently 
dropping  to  the  ground.  The  reptile  Cupid 
having  thus  exhausted  his  quiver,  becomes  in 
turn  the  object  of  a  similar  attack,  exhibiting 
apparently  an  equal  anxiety  to  avoid  the  threat- 


ening point  of  the  weapon  bared  against  him. 
At  last  he  receives  the  love-inspiring  wound, 
and  the  preliminaries  thus  completed,  each 
prepares  for  the  completion  of  their  embraces. 
The  other  two  apertures  next  dilate,  and  from 
one  of  them  issues  the  long  and  whip-like  penis, 
unrolling  itself  like  the  finger  of  a  glove  ;  this 
being  fully  developed  is  introduced  into  the 
vaginal  orifice  of  the  other  snail,  which  in  the 
same  manner  inserting  its  penis  into  the  female 
aperture  of  the  former,  both  mutually  impreg- 
nate and  are  impregnated.    See  fig.  195. 


Fig.  195. 


It  is  difficult  to  conceive  what  can  be  the 
use  of  the  dart  so  singularly  employed ;  it 
would  seem  to  bean  instrument  for  stimulating 
the  sleeping  energies  of  the  creatures  to  a 
needful  pitch  of  excitement ;  yet  why  it  should 
be  peculiar  to  the  snail  is  not  obvious,  for  in 
the  slug  and  other  Mollusca  certainly  not  less 
apathetic,  no  such  structure  has  been  detected. 

In  Vaginulus  (jig.  189)  a  similar  arrange- 
ment of  the  principal  organs  is  observable, 
although  some  modifications  are  met  with 
which  deserve  our  notice.  No  sac  of  the  dart 
is  found  in  this  animal,  but  a  fasciculus  of 
cceca,  analogous  to  the  multifid  vesicles  as  far 
as  their  structure  is  concerned,  is  connected, 
not  with  the  female  apparatus,  as  in  the  snail, 
hut  with  the  male  organs.  The  orifices  of  the 
two  sexual  systems  are  here  separated  by  a 
considerable  interval,  the  penis  emerging  at 
the  side  of  the  neck,  near  the  right  superior 
tentacle  at  z,  while  the  orifice  of  the  female 
parts  is  placed  between  the  cuirass  and  the 
mantle,  considerably  further  back.  The  ovary 
(m)  is  similar  in  structure  to  that  of  the  snail ; 
and  its  duct,  in  like  manner,  forms  many 
convolutions  in  the  substance  of  the  testicle 
(/>),  from  which  it  issues,  much  increased  in 
size,  to  expand  into  a  large  membranous  re- 
ceptacle (</),  corresponding  in  function  with 
the  tortuous  matrix  of  the  Helices;  this  part 
of  the  oviduct  is  filled  with  an  albuminous 
fluid,  and  from  it  runs  the  narrower  canal  (r), 
which  may  be  regarded  as  the  vagina,  and 
which  before  its  termination  communicates 
with  a  lateral  pouch,  identical  with  what  has 
been  called  the  bladder.  The  testicle  (p)  ap- 
pears to  consist  of  two  portions,  from  which 


arises  the  vas  deferens  (o).  On  tracing  this 
tube  it  is  seen  to  divide  into  two  branches,  one 
opening  into  the  bladder  (s),  an  arrangement 
to  which  we  shall  again  have  occasion  to  revert, 
whilst  the  other  runs  forward  to  the  root  of  the 
penis  (w).  The  latter  organ  presents  two  por- 
tions, a  long  tubular  ccecum  (i>),  resembling 
the  corresponding  part  in  the  snail,  and  a 
thick  muscular  cavity,  from  which  the  former 
arises  as  a  kind  of  appendage ;  on  opening  the 
thicker  portion  its  interior  is  seen  to  be  rugose, 
and  to  enclose  a  small  body,  something  like 
the  caput  gallinaginis  in  the  human  urethra. 
The  multijid  vesicles  (y)  open  near  the  exterior 
orifice,  through  which  the  whole  apparatus,  by 
a  process  of  inversion  already  described,  is 
protruded  so  as  to  form  the  male  organ  of  ex- 
citement. 

In  many  of  the  Tectibranchiata  a  remark- 
able arrangement  of  the  generative  organs  is 
found,  as  the  male  viscera  are  divided  into  two 
distinct  portions,  the  exciting  organ  being  at 
one  extremity  of  the  body,  while  the  testis  is 
found  connected  with  the  female  apparatus  in 
a  distant  part  of  the  system.  This  will  be 
seen  in  Doridium  Meckelii  (fig-  196);  the 
penis  (/),  seen  retracted  in  the  figure,  issues 
from  the  side  of  the  neck,  and  has  appended 
to  its  root  a  zig-zag  tube,  inclosed  in  a  mem- 
branous canal,  the  nature  of  which  is  un- 
known. Quite  detached  from  these,  and 
placed  near  the  anus,  we  have  the  matrix  (  f), 
the  testis  (g),  and  the  bladder  (i),  occupying 
their  usual  relative  position  as  regards  each 
other,  and  terminating  in  the  vulva  or  sac  of 
generation  (//). 

In  Aplysia  the  organ  of  excitement  is  found 


GASTEROPODA. 


399 


Fig.  196. 


near  the  right  tentacle,  where  it  protrudes,  as 
in  the  Snail,  for  the  purpose  of  copulation, 
by  the  inversion  of  its  walls;  it  is,  however, 
absolutely  imperforate,  and  receives  no  duct 
by  which  it  can  communicate  with  the  testis 
so  as  to  become  instrumental  in  immission; 
but  externally  a  deep  groove  is  seen  upon  its 
surface  when  in  a  state  of  protrusion,  which  is 
continuous  with  a  long  furrow  seen  upon  the 
surface  of  the  body,  continued  from  the  base 
of  the  penis  to  the  orifice  of  the  female  ap- 
paratus.   Fig.  197  represents   the  secreting 

Fig.  197. 


Generative  organs  of  Aplysiu. 


portions  of  this  system  removed  from  the  body, 
and  displayed  so  as  to  expose  the  internal 
structure  of  the  parts  composing  it.  The 
ovary  (ft)  is  a  large  oval,  whitish,  and  granular 
mass,  from  which  the  oviduct  arises  by  several 
distinct  tubes  which  emerge  from  different 
parts  of  its  substance  :  this  oviduct  opens  into 
the  common  tube  (e),  which  may  be  called  the 
vagina.  The  mass  (J]  g),  called  by  Cuvier 
the  testis,  and  supposed  by  him  to  be  solid 
and  homogeneous  in  its  texture,  is  found,  when 
opened,  to  he  divided  by  spiral  septa,  resem- 
bling the  scala  cochleae  in  the  ears  of  Mam- 
malia (g),  and  thus  forms  a  long  spiral  cavity 
communicating  with  the  commencement  of  the 
vagina,  in  which  latter  tube  we  also  find  aper- 
tures by  which  the  vesicle  ( p)  and  the  larger 
sacculus  (o)  communicate  with  the  common 
passage. 

In  Onchidium,  an  aquatic  species  belonging 
to  the  inoperculate  pulmonary  order,  the  male 
and  female  parts  are  in  a  similar  manner 
placed  at  opposite  extremities  of  the  body, 
but  the  former  assume  a  more  complicated 
structure  than  in  the  Tectibranchiata,  which 
we  have  described.  The  ovary  (Jig.  198,  a,  a,  a) 

Fig.  198. 


Generative  organs  of  Onchidium. 


consists  of  two  masses  replete  with  ova,  each 
of  which  furnishes  a  short  duct ;  the  two  thus 
formed  unite  into  a  convoluted  tube  (b),  which 
is  the  common  oviduct :  arriving  at  the  mass 
always  regarded  by  Cuvier  as  the  testis,  it 
enlarges  and  forms  within  the  substance  of 
that  organ  many  convolutions,  on  emerging 
from  which  it  runs  directly  in  the  shape  of  a 
narrow  canal  (rf),  to  the  external  orifice  (h). 
The  bladder  (j)  receives  a  large  duct  (e)  from 
the  mass  here  assumed  to  be  the  testis,  and 
gives  off  another  of  equal  size,  which  joins  the 
Oviduct  (rf)  prior  to  its  termination.  This 


40Q 


GASTEROPODA. 


would  seem  to  form  a  complete  system  in 
itself ;  yet,  on  examining  the  male  organ 
of  excitement,  we  find  it  connected  with 
considerable  appendages,  the  nature  of 
which  it  is  difficult  to  conjecture.  The  sac 
(m)  is  muscular,  and  resembles  the  mus- 
cular root  of  the  penis  in  the  genera  already 
described,  being,  as  in  them,  capable  of  in- 
version :  at  its  base  are  seen  two  cul-de-sacs, 
into  each  of  which  opens  a  long  and  flexuous 
canal  (/,  ?;).  The  canal  marked  n  is  very 
slender,  and  when  unfolded  is  four  times  the 
length  of  the  body  of  the  animal ;  its  termi- 
nation at  the  point  most  remote  from  the  mus- 
cular sac  into  which  it  opens  is  apparently 
closed.  The  other  tube  marked  /  is  much 
wider  and  of  extraordinary  length;  its  com- 
mencement (t)  is  extremely  convoluted  and  fully 
eight  times  as  long  as  the  body  ;  its  walls  are 
thin,  but  it  is  supplied  plentifully  with  blood 
by  means  of  a  large  artery  interlaced  with  its 
convolutions  ;  at  k  it  becomes  enveloped  in  a 
fleshy  mass  of  considerable  thickness,  after 
which,  assuming  its  original  appearance,  it 
proceeds  to  the  cul-de-sac,  at  the  bottom  of 
which  it  terminates.  In  Jig.  b,  1 98,  the  muscular 
cavity  (m)  has  been  laid  open,  and  the  mode 
in  which  the  above  tubes  enter  it  has  been 
displayed  ;  the  smaller  one(n)  ends  in  a  little 
horny  papilla  (q)  seen  in  the  engraving  ;  the 
larger  tube  (7)  terminates  by  a  kind  of  glans 
penis,  perforated  by  a  large  aperture  and  sur- 
rounded by  a  kind  of  prepuce  (p) :  on  open- 
ing the  vessel  a  little  before  its  entrance  into 
the  muscular  sac,  it  is  found  to  conceal  a 
sharp  horny  dart  (o),  supported  upon  a  fleshy 
pedicle,  and  readily  protrusible  through  the 
aperture  p;  the  analogy  between  this  singular 
instrument  and  the  dart  of  the  Snail  is  ob- 
vious, for  when  the  muscular  sac  («)  is 
everted,  the  papilla;  (p,  q)  become  external, 
and  the  horny  point  being  pushed  out  of  the 
former  will  probably  form  a  stimulus  of  the 
same  description. 

We  have  hitherto  abstained  entirely  from 
mixing  up  with  our  description  of  these  prin- 
cipal forms  which  the  generative  system  of  the 
mutually  impregnating  Gasteropoda  presents, 
the  discussions  which  have  arisen  concerning 
the  real  nature  of  the  different  organs  which 
have  been  described,  and  have  designated  them 
by  the  terms  usually  applied  to  the  respective 
parts,without  reference  to  their  individual  func- 
tions. It  now,  however,  becomes  necessary 
to  lay  before  our  readers  the  principal  opinions 
which  are  recorded  upon  this  subject.  The  chief 
points  of  debate  have  been  the  bladder,  and 
the  on;an  which  we  have  described  under  the 
appellation  of  testicle.  The  bladder  is,  from 
its  constant  occurrence,  evidently  an  organ  of 
some  essential  use:  it  was  regarded  by 
Swammerdam  as  the  secreting  structure  from 
which  the  colouring  fluid  peculiar  to  some 
species  is  produced,  especially  in  the  Murices 
and  others  of  the  marine  genera ;  it  was  there- 
fore named  by  him  sac  of  the  purple;  but  we 
shall  afterwards  find  that  this  fluid  is  derived 
from  another  source.    Blainville,  on  the  other 


hand,  considers  this  vesicle  as  analogous  to  the 
urinary  bladder  of  Vertebrata  ;  in  reference  to 
this  hypothesis,  however,  we  should  be  inclined 
to  ask,  with  Cuvier,  where  are  the  kidneys  ?  and 
even  upon  the  supposition  that  the  secretion  of 
the  bladder  itself  was  analogous  to  the  urinary 
fluid,  we  are  not  aware  of  any  chemical  proofs 
of  its  nature  which  are  sufficient  to  establish 
the  identity.  Delle  Chiaje  again  sustains  that 
the  sac  of  the  purple  is,  in  fact,  the  testis,  and 
that  its  secretion,  poured  as  it  constantly  is 
into  the  termination  of  the  oviduct,  is  in  re- 
ality the  fecundating  fluid  ;  yet  against  this  we 
must  urge  the  distribution  of  the  vas  deferens 
met  with  in  the  Helices,  which  from  its  entire 
arrangement  converts  the  organ  of  excitement 
in  these  animals  into  an  apparatus  of  immis- 
sion,  whose  nature  cannot  be  mistaken.  The 
opinion  which  we  consider  most  consonant 
with  all  the  circumstances  of  its  position,  is 
that  it  is  a  reservoir  for  the  seminal  fluid 
analogous  to  the  spermotheca  of  certain  insects. 
Cuvier  expressly  notices  the  constant  relation 
which  exists  between  the  length  of  the  penis 
and  that  of  the  canal  which  leads  to  this  sac- 
culus,  and  when  we  remark  the  long  chains  of 
ova  which  are  slowly  extruded  in  most  of  the 
Gasteropoda,  we  are  readily  disposed  to  admit 
of  the  necessity  of  such  a  reservoir,  which, 
treasuring  up  the  semen  until  the  eggs  are 
about  to  be  expelled,  applies  it  efficiently  to 
the  ova  as  they  successively  pass  the  orifice  of 
its  duct.  This  supposition  derives  additional 
weight  from  what  we  have  found  to  be  the 
arrangement  of  the  seminal  ducts  in  Vaginulus 
and  Onchidium.  In  the  former  we  observed 
that,  besides  the  canal,  which,  as  in  the  Snail, 
perforates  the  root  of  the  penis  and  thus  be- 
comes subservient  to  copulation,  the  vas  de- 
ferens actually  pours  a  part  of  its  contents  by 
a  separate  canal  into  the  bladder  itself,  which, 
as  in  all  cases,  communicates  with  the  egg- 
passage.  In  Onchidium  the  connexion  be- 
tween the  testis  and  this  receptacle  is  equally 
striking,  as  will  be  obvious  on  reference  to  the 
drawing  given  above.  In  Aplysia,  Delle  Chiaje 
considers  the  testicle  as  described  by  Cuvier 
to  be  in  reality  the  matrix  or  receptacle  for  the 
ova,  in  which  they  attain  their  full  development 
prior  to  expulsion,  basing  his  opinion  upon 
the  disposition  of  the  spiral  cavity  which  it 
contains. 

We  are  entirely  left  to  conjecture  as  to  the 
uses  of  the  other  appendages  found  in  par- 
ticular species,  and  the  multifid  vesicles  of  the 
Snail,  which  are  wanting  even  in  the  Slug,  the 
tortuous  canal  connected  with  the  penis  of 
Doridium,  and  the  still  more  singular  organs 
belonging  to  the  male  apparatus  of  Onchidium, 
must  still  remain  the  subjects  of  observation 
and  experiment. 

The  third  form  of  the  generative  system  in 
which  the  sexes  are  distinct,  is  met  with  in 
all  the  Pectinibranchiate  order,  and  in  the 
operculated  Pulmonalia  of  Ferussac.  In  Buc- 
cinum,  which  we  shall  select  as  an  example 
of  the  general  arrangement  of  the  sexual  organs 
in  the  former,  the  male  is  at  once  distinguish- 


GASTEROPODA. 


401 


Fig.  199. 


Male  organs  of  Buccirium. 

able  by  the  enormous  penis  attached  to  the 
right  side  of  the  neck  (jig.  199),  which  is  not, 
as  in  the  last  division,  capable  of  retraction 
within  the  body,  but  remains  permanently  ex- 
ternal, being,  when  not  in  use,  folded  back  and 
lodged  within  the  branchial  cavity,  from  which 
however  it  is  frequently  protruded  without  any 
apparent  object. 

In  the  female  there  is  no  rudiment  of  such 
a  structure,  but  the  generative  aperture  is  seen 
to  be  situated  a  little  within  the  edge  of  the 
pulmonary  cavity,  being  a  simple  hole  leading 
to  the  oviduct.  The  internal  organs  of  the 
male,  represented  in  the  annexed  figure,  con- 
sist simply  of  a  testicle  and  its  excretory  canal. 
The  testis  is  of  considerable  size,  sharing  with 
the  liver  the  smaller  convolutions  of  the  shell ; 
from  this  arises  the  vas  deferens,  which  forms 
by  its  convolutions  a  kind  of  epididymis 
(Jig.  199,  b),  and  then  increasing  in  diameter 
enters  the  root  of  the  penis,  through  which  it 
passes  by  a  tortuous  course  (d)  to  the  tubercle  at 
the  extremity  of  this  organ,  where  it  opens 
externally.  The  penis  when  opened,  as  re- 
presented in  the  engraving,  is  seen  to  contain 
strong  transverse  fasciculi  of  muscle,  which 
probably  cause  the  erection  of  this  organ  ;  they 
will  at  the  same  time  lengthen  it,  so  as  to 
destroy  in  a  great  measure  the  zig-zag  turns 
into  which  the  vas  deferens  is  thrown  in  its 
usual  relaxed  state. 

In  the  female  the  position  of  the  testicle  is 
occupied  by  the  ovary,  while  the  vas  deferens 
is  represented  by  a  thick  and  glandular  oviduct. 

In  Mures  the  penis  of  the  male  is  pro- 
portionally smaller;  and,  instead  of  a  com- 
plete vas  deferens,  penetrating  to  its  extremity, 
there  is  merely  a  groove  along  its  surface,  along 
which  the  semen  flows.  In  Voluta  the  ex- 
terior groove  only  runs  to  the  base  of  the  penis, 
and  in  Strombus  the  male  organ  is  a  mere 
tubercle. 

In  the  Pulmonalia  operculaia  the  organs  of 
both  sexes  are  in  every  respect  similar  to  those 
of  the  Pectin ibranchiale  order.  In  Valudina 
alone  ( Helix  vivipara,  Lin.)  the  penis  is  retrac- 


til  e,  issuing  from  ahole  found  in  the  right  tentacle, 
and  from  the  disparity  in  size  between  the 
tentacles,  arising  from  this  cause,  the  male  is 
readily  distinguished.  The  females  of  this 
genus  are  not  unfrequently  ovo-viviparous, 
the  ova  remaining  in  their  capacious  oviduct 
until  they  are  hatched. 

Spallanzani  asserts  that,  if  the  young  of 
Paludina  are  taken  at  the  moment  of  their 
birth,  and  kept  entirely  separate  from  others  of 
their  species,  they  can  reproduce  without  im- 
pregnation, like  the  Aphides  and  Monoculi, 
in  which  the  same  connexion  with  the  male 
is  found  to  fecundate  not  only  the  female 
herself,  but  her  offspring  for  several  generations. 
Nevertheless,  whether  Spallanzani's  observa- 
tions be  correct  or  not,  the  males  are  fully  as 
numerous  as  the  females,  so  that  it  would  be 
difficult  to  imagine  the  object  of  such  a  de- 
viation from  the  ordinary  proceedings  of  na- 
ture. 

Ova. — The  spawn  of  the  Gasteropod  Mol- 
lusca  is  found  under  diverse  forms  ;   it  is 
usually  in  the  marine  species  attached  to  the 
surface  of  stones,  shells,  or  sea-weed,  the  ova 
being  connected  with  each  other  in  long  ri- 
bands or  delicate  festoons,  which  are  some- 
times extremely  beautiful  and  curious.  The 
Doris  and  Tritonia  deposit  their  ova  in  this 
manner,  and  the  mass  of  eggs  deposited  by 
them  resembles  a  frill  of  lace   of  extreme 
beauty.    In  Aplysia  the  spawn  is  found  to 
resemble  long  gelatinous  threads,  in  the  centre 
of  which  the  ova  are  seen,  varying  in  tint,  so 
as  to  give  different  colours  to  different  parts  of 
the  thread;   the   whole  strikingly  resembles 
strings  of  vermicelli,  and  the  Italians  in  fact 
have  applied  to  them  the  name  of  vermicelli 
murini.    In  Helix  and  Bulimus  the  eggs  are 
naked  and  protected  by  a  hard  shell,  whilst  in 
Buccinum,  Voluta,  Murex,  and  other  marine 
species,  the  ova  are  enveloped  in  membranous 
sacs  agglomerated  together  in  large  bunches ; 
these  sacs  have  been  erroneously  regarded  as 
the  eggs  themselves;  they  are,  however,  merely 
coriaceous  envelopes,  answering  the  purpose 
of  the  gelatinous  coating  enclosing  the  eggs  of 
other  species,  several  eggs  being  contained  in 
each  bag,  in  which,  when  mature,  the  young  are 
easily  seen.    It  would  seem  that  extraordinary 
provisions  have  been  made  by  nature  for  the 
multiplication  of  these  creatures,  in  spite  of 
the  numerous  enemies  which  devour  them,  or 
the  vicissitudes  of  temperature  to  which,  espe- 
cially in  the  terrestrial  species,  their  eggs  are 
necessarily  subject.    We  are  indebted  to  M. 
Leuchs   for    several    interesting  observations 
concerning  the  ova  of  slugs,  which  explain  in 
a  great  degree  the  quantities  of  them  which  in 
some  seasons  infest  gardens  and  vineyards, 
becoming,   from  the  devastation  which  they 
cause,   serious  plagues  to  the  agriculturist. 
The  number  of  eggs  varies  with  the  healthiness 
of  the  animal,  the  supply  of  food,  or  the  tem- 
perature of  the  season  ;  yet  it   is  probable 
that  a  single  slug  will  lay  five  hundred,  under 
ordinary  circumstances :    thus,   supposing  a 
thousand  of  these  creatures  to  be  collected  in 


402 


GASTEROPODA. 


a  given  space,  they  will  give  birth  in  a  few 
weeks  to  five  hundred  thousand  young  slugs, 
which  multiplying  in  their  turn  would  pro- 
duce at  the  second  laying  two  hundred  and 
fifty  millions  of  eggs.  This  fact  is  well  worth 
the  notice  of  the  farmer,  who,  instead  of  dri- 
ving away  with  so  much  assiduity  crows  and 
other  birds  which  live  upon  these  destructive, 
though  apparently  insignificant,  animals,  would 
do  well  occasionally  to  cherish  them  as  fellow- 
labourers  in  his  grounds.  The  Terrestrial  Mol- 
lusca,  helpless  and  incapable  of  defence, 
afford  food  to  numberless  indefatigable  assail- 
ants, and  their  preservation  is  provided  for, 
not  only  by  the  number  of  their  eggs,  but  by 
a  peculiar  tenacity  of  vitality  which  these  ex- 
hibit under  circumstances  which  would  be 
thought  sufficient  to  destroy  the  young  before 
they  were  hatched.  The  skin  of  the  eggs  of 
the  slug  is  coriaceous  and  very  elastic,  so  that 
when  compressed  they  soon  resume  their 
shape  :  exposure  to  intense  cold  does  not  de- 
stroy their  fertility,  and  they  have  been  known 
to  resist  a  temperature  of  40°  without  ap- 
parent injury.  When  dried  by  artificial  heat, 
they  shrivel  up  to  minute  points  only  distin- 
guishable by  the  microscope,  yet  in  this  state, 
if  they  be  put  into  water,  they  readily  absorb  it 
and  are  restored  to  their  former  plumpness. 
The  same  thing  happens  to  those  which  are 
dried  by  the  action  of  the  sun  and  apparently 
destroyed;  a  shower  of  rain  is  sufficient  to 
supply  them  with  the  fluid  which  they  had  lost 
and  to  restore  their  fertility.  This  drying  ap- 
pears not  to  injure  them.  M.  Leuchs  found 
that  after  being  eight  times  treated  in  this 
manner,  they  were  hatched  on  being  placed  in 
favourable  circumstances,  and  even  eggs  in 
which  the  embryo  was  distinctly  formed,  sur- 
vived such  treatment  without  damage. 

Reproduction  of'  lost  parts. — Not  less  won- 
derful is  the  power  which  snails  possess  of  repro- 
ducing lost  parts,  after  mutilation  by  accident 
or  design.  The  results  of  the  experiments  of 
Spallanzani  upon  this  subject  are  very  curious ; 
he  found  that  if  the  large  tentacle  of  a  snail 
were  amputated,  the  extremity  of  the  stump 
heals,  forming  a  small  swelling  of  a  lighter 
colour  than  the  rest  of  the  horn ;  in  this  swel- 
ling a  black  point  soon  becomes  visible,  which 
is  a  new  eye,  and  the  mutilated  member,  in- 
creasing in  length,  shortly  equals  its  original 
size,  although  it  is  for  some  time  of  a  lighter 
colour  than  its  uninjured  fellow,  which  in  other 
respects  it  perfectly  resembles.  The  process 
sometimes  varies  a  little ;  it  frequently  happens 
that  the  end  of  the  stump,  instead  of  becom- 
ing round,  is  elongated  and  tapers  to  a  point, 
from  the  apex  of  which  the  new  eye  is  seen  to 
"  squeeze  out ;"  the  end  of  the  tentacle  then 
assumes  a  globular  shape,  and  the  most  accu- 
rate dissection  cannot  distinguish  the  newly 
formed  eye  from  the  original.  If,  instead  of 
the  horn,  the  head  is  cut  quite  off,  a  new  one 
will  succeed  :  the  new  head,  however,  does  not 
at  first  contain  all  the  parts  of  the  old  one, 
but  they  are  gradually  developed,  piece  by 
piece,  at  different  intervals,  until  at  length  a 


head  differing  little,  if  at  all,  from  the  original 
pattern  is  completed.  In  some  cases  the  ob- 
ject is  effected  by  a  different  proceeding,  the 
new  part  appearing  like  a  round  tubercle,  con- 
taining the  rudiments  of  the  lips  and  of  the 
smaller  horns,  which  is  united  to  the  mouth 
and  the  new-formed  tooth,  the  other  parts, 
as  the  larger  horns  and  the  anterior  part  of  the 
foot,  being  totally  deficient.  In  another  snail 
the  larger  tentacle  on  the  right  side  first  ap- 
peared, not  more  than  one-tenth  of  an  inch 
in  length,  but  already  provided  with  its  eye, 
and  at  a  short  distance  beneath  this  the  linea- 
ments of  the  lips  separately  developed  them- 
selves. In  a  third  snail  a  group  of  three  horns 
is  seen,  two  of  which  will  acquire  their  full 
developement,  while  the  third  is  just  above  the 
level  of  the  skin.  These  and  many  other 
varieties  have  been  observed ;  but  in  most 
instances  there  is  no  perceptible  difference 
between  the  new  head  and  the  one  cut  off, 
the  exact  line  of  separation  being  indicated 
by  an  ash-coloured  mark  distinguishable  two 
years  after  the  experiment.  The  same  effects 
follow,  whether  the  head  be  removed  above  or 
below  the  brain,  and  in  the  latter  case  a  new 
brain,  with  all  its  nerves,  is  speedily  con- 
structed. The  collar  and  foot  are  also  per- 
fectly restored  after  their  removal. 

Slugs  reproduce  their  horns  as  well  as  snails, 
but  their  power  of  manufacturing  a  new  head 
is  much  inferior. 

Muscular  integument. — None  of  the  Gaste- 
ropoda have  any  thing  analogous  to  an  endo- 
skeleton,  a  circumstance  which  sufficiently  ac- 
counts for  the  varied  forms  which  the  same  in- 
dividual assumes  under  different  circumstances, 
for  the  body  being  unsupported  by  any  re- 
sisting framework,  readily  yields  to  the  con- 
tractions of  the  muscular  integument  with 
which  it  is  covered.  It  is  from  this  circum- 
stance that  the  zoologist  finds  the  preservation 
of  the  natural  forms  of  the  recent  animals  a 
task  of  such  extreme  difficulty,  owing  to  the 
corrugation  and  distortion  produced  by  the  or- 
dinary modes  of  preservation ;  it  is  scarcely 
possible  indeed,  in  many  cases,  to  recognise 
with  tolerable  accuracy  the  natural  appearance 
of  these  creatures  in  the  shrunken  specimens 
generally  preserved  in  our  cabinets,  and  the 
collector  of  these  objects  would  do  well  never 
to  omit,  when  circumstances  allow  him  the  op- 
portunity, to  preserve  some  sketch  of  the  living 
forms  of  such  exotic  species  as  may  come  into 
his  possession. 

Body. — In  the  naked  Gasteropods  the  whole 
body  is  found  to  be  inclosed  in  a  muscular  in- 
tegument, the  basis  of  which  is  a  cellular  web 
of  extraordinarily  extensible  character,  in  which 
the  muscular  fibres  may  be  seen  to  cross  each 
other  in  various  directions,  some  passing  longi- 
tudinally from  one  extremity  of  the  animal  to- 
wards the  opposite  end,  while  others,  assuming 
different  degrees  of  obliquity,  are  interwoven 
with  the  rest,  so  as  to  occasion  the  elongation 
or  contraction  of  the  body  in  every  assignable 
direction.  Within  this  muscular  bag  the  vis- 
cera are  contained,  as  well  as  the  organs  sub- 


GASTEROPODA. 


403 


servient  to  mastication,  the  apparatus  of  the 
external  senses,  and  of  the  organs  employed  in 
copulation,  which  are,  when  unemployed,  re- 
tracted within  its  cavity  by  special  muscular 
fasciculi  spoken  of  elsewhere. 

Retractile  muscles. — In  the  spirivalve  genera 
the  muscular  walls  which  inclose  the  body  only 
exist  in  such  parts  as,  during  the  extended  state 
of  the  animal,  are  protruded  from  the  shell ; 
that  part  of  the  body  which  is  concealed  within 
its  cavity  being  provided  with  a  much  more 
delicate  and  membranous  envelope  ;  in  such, 
however,  a  necessity  exists  for  an  additional 
muscular  apparatus,  serving  to  retract  the  body 
and  foot  within  the  cavity  of  its  calcareous 
abode,  and  of  course  exhibiting  various  modifi- 
cations of  arrangement  in  conformity  with  the 
shape  of  the  shell  itself.  In  the  turbinated 
shells,  the  retracting  muscles  consist  of  strong 
fasciculi  of  fibres  arising  from  the  columella 
or  axis  of  the  shell,  and  diverging  from  this 
point,  spread  in  several  slips,  which  become 
interlaced  with  the  fibres  composing  the  foot 
and  muscular  investment.  In  the  flattened 
forms  of  Patella  and  Chiton,  the  muscular 
fibres  arise  all  around  the  margin  of  the  shell, 
excepting  at  its  anterior  part;  these  penetrating 
the  mantle  are  intimately  interwoven  with  the 
muscles  forming  the  circumference  of  the  foot. 
The  animal  of  the  Haliotis  is  fixed  to  its  ex- 
panded and  semi-turbinated  shell  by  a  single 
large  and  ovoid  muscle,  which  takes  its  origin 
from  near  the  middle  of  the  last  spire ;  what- 
ever the  disposition  of  these  muscles,  however, 
their  action  is  obviously  of  two  kinds ;  and  not 
only  are  they  the  agents  by  which  the  creature 
retires  within  its  covering,  but  by  raising  the 
central  portion  of  the  disc  of  the  foot,  whilst  its 
margins  are  in  apposition  with  the  plane  of 
progression,  they  will,  by  producing  a  vacuum 
beneath,  convert  the  whole  apparatus  into  a 
sucker,  the  adhesive  power  of  which  will  be 
proportioned  to  the  extent  of  its  surface. 

Foot. — The  foot  of  the  Gasteropoda  is  their 
principal  agent  of  progression.  It  is  generally 
a  fleshy  disc,  of  variable  size  and  shape,  attached 
to  the  ventral  surface,  and  forming  when  ex- 
panded an  organ  by  means  of  which  the  animal 
can  adhere  to  surrounding  objects.  In  the 
naked  genera  it  is  small,  but  in  the  conchife- 
rous  species,  especially  in  such  as  are  provided 
with  dense  and  weighty  shells,  its  dimensions 
and  force  are  proportionally  increased.  In  its 
internal  structure  it  resembles  the  muscular  in- 
vestment of  the  body,  of  which  in  fact  it  is 
merely  an  expansion,  consisting  of  muscular 
fibres  interlacing  each  other  in  every  possible 
direction,  as  may  be  developed  by  continued 
maceration.  In  the  Slug,  when  opened  from 
the  back,  the  superior  layer  of  fibres  is  found  to 
run  transversely,  arising  apparently  from  two 
tendinous  lines  which  run  longitudinally  near 
the  centre  of  the  organ,  and  terminating  near 
the  margins  of  the  disc  ;  beneath  these,  longi- 
tudinal fasciculi  may  be  detected,  but  so  inter- 
laced with  other  fibres  assuming  every  degree 
of  obliquity,  that  it  is  impossible  to  unravel  the 
complicated  structure  which  they  form.  In  the 
Limpet  (Patella)  the  lower  fibres  of  the  foot 


are  transverse,  but  near  the  circumference  they 
become  distinctly  interwoven  with  circular  fas- 
ciculi ;  the  superior  stratum  viewed  from  above 
consists  of  two  series  of  oblique  fibres,  which 
meet  at  an  acute  angle  on  the  middle  line, 
whilst  the  substance  of  the  organ  is  composed 
of  muscular  bands  variously  disposed  :  from 
such  a  structure  the  movements  of  the  foot  are 
readily  understood ;  the  transverse  fibres  by 
their  contraction  will  elongate  the  ellipsis  of 
the  foot  by  diminishing  its  breadth,  whilst  the 
longitudinal,  having  a  contrary  action,  will,  by 
the  combination  of  their  effects,  produce  every 
movement  needful  for  the  progression  of  the 
creature.  On  minutely  inspecting  the  foot  of 
a  terrestrial  Gasteropod,  as  it  crawls  upon  a 
transparent  surface,  it  will  be  found  to  be 
divided  into  a  certain  number  of  transverse  seg- 
ments of  variable  size  by  a  particular  arrange- 
ment of  the  longitudinal  muscular  fibres,  which 
seem  to  form,  when  the  creature  advances,  un- 
dulations limited  by  the  points  of  contact. 
These  sections  appear  alternately  to  form  a 
vacuum  upon  the  surface  where  the  animal  is 
placed,  that  which  follows  advancing  to  take 
the  place  of  that  which  precedes  it,  the  trans- 
mission of  movement  occurring  from  behind 
forwards,  a  mechanism  which  causes  the  animal 
to  advance  by  a  slow  and  uniform  progression. 

The  above  structure  of  the  foot,  and  conse- 
quent mode  of  locomotion,  although  the  most 
usual,  is  susceptible  of  considerable  modifica- 
tion. Thus  in  Sci/llaa,  we  find  it  only  adapted 
for  grasping  the  thin  stems  of  fuci  and  other 
submarine  plants,  being  for  that  purpose  com- 
pressed and  grooved  inferiorly  into  a  deep  sul- 
cus. In  the  Tornatella  fusciata,  Lam.  the  struc- 
ture of  the  foot  is  remarkable :  beaten  incessantly 
by  the  waves,  in  the  cavities  of  rocks  which  it 
frequents,  nearly  on  a  level  with  the  surface  of 
the  sea,  to  the  violence  of  which  it  is  always 
exposed,  it  has  need  of  additional  powers  of 
retaining  its  hold ;  its  foot  is  therefore  divided 
into  two  adhering  portions,  placed  at  each 
extremity,  and  separated  by  a  wide  interval ; 
when  it  crawls  it  fixes  the  posterior  disc  and 
advances  the  other,  which  it  attaches  firmly  to 
the  plane  of  progression,  and  this  being  effected, 
the  hinder  sucker  is  detached  and  drawn  for- 
wards, locomotion  being  accomplished  by  the 
alternate  adhesion  of  these  two  prehensile  discs. 
In  Cyclostorna  the  foot  is  likewise  furnished 
with  two  longitudinal  adhering  lobes,  which 
are  advanced  alternately.  But  the  foot  is  not 
merely  an  instrument  of  progression  on  a  solid 
surface,  in  many  species  being  convertible,  at 
the  will  of  the  animal,  into  a  boat,  by  means  of 
which  the  creature  can  suspend  itself  in  an  in- 
verted position  at  the  surface  of  the  water, 
where  by  the  aid  of  its  mantle  and  tentacles,  it 
can  row  itself  from  place  to  place.  The  Buli- 
mus  stagnalis,  so  common  in  our  pools  of  fresh 
water,  is  a  good  example  of  this  mode  of  sail- 
ing ;  and  in  the  marine  species,  Aplysia  and 
Gastropteron  may  be  enumerated  as  exhibiting 
a  similar  structure. 

Some  of  the  naked  Gasteropods,  as  Aplysia 
and  Thethys,  are  able  to  move  through  the 
water  in  the  same  manner  as  the  leech  by  an 


404 


GELATIN. 


undulatory  movement  of  the  whole  body,  a 
mode  of  progression  which  in  Thethys  is  mate- 
rially assisted  by  the  membranous  expansion  of 
the  mantle  placed  around  the  anterior  part  of 
the  body,  which  forms  a  broad  veil,  and  from 
the  muscular  fibres  contained  within  it,  must 
necessarily  be  an  important  agent  in  swim- 
ming. 

Particular  secretions. — Many  of  the  Gaste- 
ropoda, in  addition  to  the  secretions  which 
have  been  mentioned,  furnish  others  adapted 
to  peculiar  circumstances,  and  produced  from 
special  organs. 

In  the  Snail  and  the  Slug  tribes  a  slimy 
mucus  is  furnished  in  great  abundance  from  an 
organ  which  has  been  denominated  the  "  sac 
of  the  viscosity  ;"  this  is  a  membranous  bag  sur- 
rounding the  pericardium,  which  when  opened 
is  found  to  be  divided  internally  by  delicate 
septa  arising  from  its  walls  ;  from  this  proceeds 
a  capacious  duct,  which  follows  the  course  of 
the  rectum,  to  which  it  is  intimately  united,  to 
open  externally  in  the  neighbourhood  of  the 
respiratory  aperture.  The  viscid  secretion  of 
this  gland  spreading  over  the  surface  of  the 
foot  is  most  probably  an  assistant  in  progres- 
sion, causing  it  to  adhere  more  intimately  to 
the  surfaces  over  which  the  animal  crawls. 

Aplysia  furnishes  three  distinct  fluids  issuing 
from  different  parts  of  the  body.  The  first  is  a 
glairy  mucus,  which  exudes  in  considerable 
quantities  from  the  surface  of  the  mantle,  espe- 
cially when  the  creature  is  irritated.  The  se- 
cond i-  a  whitish  liquor,  which  is  thick  and 
acrid,  and  has  been  reputed  venomous;  it  is 
emitted  in  very  small  quantities,  but  its  smell 
is  strong  and  highly  nauseous:  the  gland  which 
produces  it  is  a  little  reniform  mass  placed  near 
the  vulva,  close  to  which  is  the  orifice  of  its 
excretory  canal.  Blainville  looks  upon  this  as 
the  representative  of  a  urinary  apparatus,  but  it 
does  not  appear  to  exist  in  all  the  species,  and 
is  never  emitted  except  when  the  animal  is  tor- 
mented. 

The  third  secretion  is  much  more  abundant 
than  the  other  two,  and  is  generally  of  a  beau- 
tiful lake  colour,  except  in  Aplysia  citrina,  in 
which  it  is  yellow.  It  is  contained  in  a  spongy 
substance,  which  occupies  all  those  portions  of 
the  little  mantle  or  operculum  to  which  the 
shell  does  not  extend.  All  the  areolae  of  this 
tissue  are  filled  with  a  purple  matter,  the  colour 
of  which  is  so  intense,  that  when  it  is  expressed 
it  has  a  black  violet  hue,  but  when  mixed  with 
a  large  quantity  of  water,  imparts  to  it  the  co- 
lour of  port  wine.  This  colouring  fluid  seems 
to  exude  through  the  skin  of  the  mantle,  no  ex- 
cretory duct  having  been  found  specially  ap- 
propriated to  its  escape  :  it  is  apparently  pro- 
duced from  a  triangular  glandular  mass  situated 
in  the  base  of  the  mantle. 

Several  speeies  of  Murex  secrete  a  similar 
fluid,  which,  like  the  ink  of  the  cuttle-fish, 
serves  as  a  defence  from  attack ;  in  all  cases  it 
is  expelled  with  force,  and  in  such  abundance 
as  to  colour  the  water  around  to  a  considerable 
distance. 

There  is  a  species  of  Limax,  (Limax  nocti- 
lucus, ) described  by  M.  Orbigny,which  produces 


a  phosphorescent  secretion  capable  of  emitting 
a  light  of  considerable  brilliancy.  The  luminous 
organ  is  a  small  disc  of  a  greenish  colour  by 
day-light,  soft  in  texture,  and  slightly  contractile. 
The  light  is  only  visible  when  the  creature  is 
expanded  and  in  motion.  The  disc  is  always 
covered  with  a  greenish  mucus,  which,  if  wiped 
off,  is  speedily  renewed.  It  is  found  to  be 
connected  with  the  generative  organs,  and  ap- 
pears to  be  principally  useful  during  the  season 
of  love. 

BIBLIOGRAPHY. — Swammerdam,  Biblia  Naturae 
seu  Historia  Jnsectorum,  t'ol.  1737.  Cuvier,  G. 
Lecon9  d'Anatomie  Comparee,  8vo.  1799.  Ibid. 
Memoires  pour  servir  a  l'Histoire  et  I'Anatomie  des 
Mollusques,  4to.  1817.  Be  Blainville,  de  l'Orga- 
nization  des  Animaux,  on  Principes  d'Anatomie 
Comparee,  8vo.  1822.  Belle  Chiaje,  Memorie  sulla 
storia  e  notomia  degli  animali  senza  vertebre  del 
Regno  di  Napoli,  Ferussac,  Histoire  des  Mollus- 
ques  terrestres  et  fluviatiles,  fol.  Spallanxani, 
Opuscoli  di  Fisica  animale  e  vegetabile,  1776. 
Reaumur,  De  la  formation  ct  de  l'accroisse- 
ment  des  coquilles  des  animaux  tant  terrestres 
qu'aquatiques,  in  the  Memoires  de  l'Acad.  des 
Sciences,  1709.  He  continued  the  subject  in  the 
same  work  for  1716,  under  the  title  of  Eclaircisse- 
mens  des  quelques  difficultes  sur  la  formation  et 
l'accroissement  des  coquilles.  Hatchett,  on  the 
chemical  Composition  of  Shells,  Phil.  Trans.  1799- 
1800.  Beaudant,  Memoire  sur  la  structure  des 
parties  solides  des  Mollusques,  Annales  du  Museum, 
torn.  xvi.  p.  66.  Weiss,  M.  Sur  la  progression  des 
Gasteropodes  Terrestres,  Journ.  de  Physique  de 
Rozier,  An.  i.  p.  410.  Lamarck,  Systeme  des  Ani- 
maux sans  Vertebras,  7  vol.  8vo.  1815-1822.  Har- 
derus,  Examen  Anatomicum  cochlear  terrestris  do- 
miportse,  Basileas,  1679. 

(  T.  Ri/mer  Jones.) 

GELATIN  (Fr.  gelatine;  Germ.  Leim. 
Gallerte ).  This  term  is  applied  to  an  im- 
portant principle  obtained  by  boiling  certain 
animal  substances  in  water,  and  filtering  or 
straining  the  solution,  which,  if  sufficiently 
concentrated,  gelatinises,  or  concretes  into  a 
translucent  tremulous  mass  on  cooling,  which 
may  be  again  liquefied  and  gelatinised  by 
heat  and  cold.  Many  varieties  of  gelatin 
occur  in  commerce,  of  which  glue  is  perhaps 
the  most  important :  it  is  obtained  by  boiling 
the  refuse  pieces  of  skin  and  hide,  and  the 
scrapings  and  clippings  from  the  tan-yard,  in 
a  sufficient  quantity  of  water,  till  a  sample 
taken  out  of  the  boiler  forms,  on  cooling,  a 
stiff  jel ly ;  the  solution  is  then  strained  whilst 
hot,  and  run  into  coolers,  where  it  concretes,  and 
is  afterwards  cut  by  a  wire  into  slices,  which 
are  dried  upon  nets.  Membranes,  tendons, 
cartilage,  horn-shavings,  and  other  similar  sub- 
stances also  yield  a  jelly,  which,  however,  is 
less  stiff  and  binding  than  the  former,  espe- 
cially when  obtained  from  young  animals : 
size  is  a  jelly  of  this  description.  Isinglass, 
which  consists  of  several  parts  of  the  entrails 
of  fish,  and  especially  the  sound,  &c.  of  the 
sturgeon,  yields  a  very  pure  and  tasteless  jelly, 
which  is  chiefly  used  for  the  table ;  the  jelly 
of  calves'  feet  and  hartshorn-shavings  is  some- 
what similar. 

As  jelly  cannot  be  extracted  by  cold  water, 
and  as  we  have  no  direct  evidence  of  its 
existence  in  the  various  substances  from  which 


GELATIN. 


405 


it  is  obtained  previous  to  the  action  of  boiling 
water,  and,  moreover,  as  it  does  not  occur 
in  any  of  the  animal  fluids  or  secretions,  it 
has  been  regarded  by  some  chemists,  and 
especially  by  Berzelius,  as  a  product  of  the 
action  of  water  and  heat,  and  not  as  a  mere 
educt.  He  compares  its  formation  to  the 
conversion  of  starch  into  gum  and  sugar,  and 
remarks  that  in  both  cases  the  change  is  ac- 
celerated by  the  presence  of  dilute  acids. 

Pure  gelatin  is  colourless,  transparent,  in- 
odorous, insipid,  and  neither  acid  nor  alkaline  ; 
heat  softens  it  and  exhales  a  peculiar  odour, 
and  it  burns  with  smoke  and  flame,  leaving 
a  bulky  coal,  difficult  of  incineration  and 
containing  phosphate  of  lime  :  it  yields  much 
ammonia,  and  the  other  ordinary  products  of 
analogous  animal  compounds,  when  subjected 
to  destructive  distillation. 

In  cold  water  dry  gelatin  swells  and  be- 
comes opaque,  and  when  gently  heated  it 
dissolves  and  forms  a  clear  colourless  solution, 
which  gelatinises  when  cold.  According  to 
Dr.  Bostock,  one  part  of  isinglass  to  100 
parts  of  water  yields  a  perfect  jelly,  but  with 
180  of  water  it  does  not  concrete.*  Those 
modifications  of  gelatin  which  are  the  least 
soluble  in  hot  water  yield  the  strongest  jelly. 
When  the  same  portion  of  jelly  is  repeatedly 
liquefied  and  cooled,  it  gradually  loses  the 
property  of  gelatinising,  and  becomes  so  far 
modified  as  to  leave  a  brownish  gummy  residue 
when  evaporated,  which  readily  dissolves  in 
cold  water.  L.  Gmelin  kept  a  solution  of 
isinglass  in  a  sealed  tube  for  several  weeks 
at  the  temperature  of  212°  :  it  was  thus 
changed  to  the  consistency  of  turpentine,  was 
deliquescent,  soluble  in  cold  water,  and  par- 
tially so  in  alcohol. 

An  aqueous  solution  of  gelatin  exposed  for 
some  time  to  the  air  at  the  temperature  of 
60°  to  70°  becomes  at  first  thinner  and  sour, 
and  afterwards  ammoniacal  and  fetid :  the 
addition  of  acetic  acid  prevents  the  putrefac- 
tion without  impairing  the  adhesive  power  of 
the  gelatin. 

Gelatin  is  insoluble  in  alcohol  and  ether, 
and  in  the  fixed  and  volatile  oils.  When  a 
strong  aqueous  solution  of  gelatin  is  dropped 
into  alcohol,  it  forms  a  white  adhesive  and 
elastic  mass,  which  adheres  strongly  to  the 
glass,  and  which,  like  dry  gelatin,  softens,  but 
does  not  dissolve  in  cold  water. 

When  chlorine  is  passed  through  a  warm 
and  somewhat  concentrated  solution  of  gelatin, 
each  bubble  becomes  covered  with  an  elastic 
film,  and  deposits,  on  bursting,  a  white,  tough 
viscid  matter;  the  whole  of  the  gelatin  is  thus 
precipitated,  and  free  muriatic  acid  is  formed. 
This  chloride  of  gelatin  is  insoluble  in  water 
and  alcohol,  and  remains  acid,  and  smells 
of  chlorine,  even  after  it  has  been  kneaded 
in  warm  water.  Dissolved  in  caustic  am- 
monia in  a  tube  over  mercury,  it  evolves 
nitrogen  and  becomes  mucilaginous.  It  is 
soluble  in  acetic  acid;  but  the  solution,  though 
rendered  turbid  by  dilution,  gives  no  preci- 

*  Nicholson's  Journal,  xi.  244. 


pitate  by  ferro-cyanuret  of  potassium,  so  that 
the  gelatin  is  not  thus  converted  into  albumen, 
No  analogous  compound  is  produced  either 
by  iodine  or  bromine. 

The  action  of  sulphuric  acid  on  gelatin 
has  been  studied  by  Braconnot.*  When  one 
part  of  glue  and  two  of  sulphuric  acid  are 
mixed,  they  form  in  twenty-four  hours  a  clear 
fluid,  which,  when  diluted  with  eight  parts 
of  water,  boiled  for  eight  hours,  (the  loss  by 
evaporation  being  replaced  by  fresh  portions 
of  water,)  and  then  neutralised  by  chalk, 
filtered,  evaporated  to  the  consistency  of  syrup, 
and  set  aside  for  a  month,  yields  a  crystalline 
crust  of  a  peculiar  saccharine  substance,  which 
is  insoluble  in  alcohol  and  ether,  unsusceptible 
of  vinous  fermentation,  and  gives  ammonia 
by  destructive  distillation.  It  combines  and 
forms  a  peculiar  crystallisable  compound  with 
nitric  acid,  which  he  calls  the  nitro-saccharic 
acid,  and  which  combines  with  the  salifiable 
bases  and  forms  distinct  salts,  the  Droperties 
of  which  closely  resemble  the  carbuzotates. 

Dilute  nitric  acid  dissolves  gelatin  without 
the  evolution  of  nitrous  gas,  and  forms  a  yellow 
solution,  which,  by  evaporation,  (or  the  ad- 
dition of  an  alkali,)  becomes  darker,  and  at 
last  evolves  nitrous  gas,  and  passes  (often  with 
ignition)  into  a  spongy  coal.f  By  concen- 
trated nitric  acid  gelatin  is  converted  into 
malic  and  oxalic  acids,  a  fatly  substance,  and 
artificial  tan. J 

Acetic  acid  dissolves  gelatin  and  the  solution 
does  not  gelatinise,  but  upon  drying,  the  ad- 
hesive power  of  the  gelatin  is  unimpaired : 
the  dilute  acids  do  not  generally  prevent  ge- 
latinisation. 

Neither  the  dilute  caustic  alkalis  nor  am- 
monia prevent  the  concretion  of  a  solution  of 
gelatin,  but  they  render- it  turbid  by  precipi- 
tating its  phosphate  of  lime.  Gelatin  is  soluble 
in  strong  caustic  potash,  with  the  exception 
of  a  residue  of  phosphate  of  lime.  The  solu- 
tion, when  neutralised  by  acetic  acid,  does 
not  gelatinise,  and  yields  on  evaporation  a 
compound  of  gelatine  with  acetate  of  potash, 
which  is  soluble  in  alcohol.  Sulphuric  acid 
precipitates  sulphate  of  potash  from  this  acetic 
solution,  in  combination  with  gelatin  ;  and 
this  compound  precipitate,  dissolved  in  water, 
crystallizes  by  spontaneous  evaporation  to  the 
last  drop.§ 

Hydrate  of  lime  does  not  affect  a  solution 
of  gelatin,  but  much  lime  is  dissolved  by  it: 
it  also  takes  up  a  considerable  quantity  of 
recently  precipitated  phosphate  of  lime. 

Gelatin  is  not  precipitated  by  solution  of 
alum,  but  when  an  alkali  is  added  the  alurnine 
falls  in  combination  with  gelatin.  The  alu- 
minous solution  of  gelatin  is  used  for  sizing 
paper,  and  for  communicating  to  woollen 
cloth  a  certain  degree  of  impenetrability  to 
water. 

The  acetates  of  lead  do  not  precipitate  pure 
gelatin;  by  corrosive  sublimate  its  solution  is 

*  Annalcs  de  Chim.  et  Pliys.  xiii. 

t  Hatchett,  Phil.  Trans.  1800,  p.  369. 

t  Ibid. 

§  Berzelius. 


406 


ORGANS  OF  GENERATION. 


rendered  at  first  turbid,  and  when  excess  is 
added  a  white  adhesive  compound  falls:  nitrate 
and  per-nitrate  of  mercury  and  chloride  of  tin 
occasion  nearly  similar  changes.  But  the  me- 
tallic salt  which  is  the  most  decided  precipitant 
of  gelatin,  and  which  does  not  affect  albumen, 
is  sulphate  of  platinum ;  it  throws  it  down 
even  from  very  dilute  solutions,  in  the  form 
of  brown  flocculi,  which,  when  collected  and 
dried,  become  black  and  brittle,  and  which, 
according  to  Mr.  Edmund  Davy,  to  whom  we 
owe  this  effective  test,  consist  of  about  76  per 
cent,  of  sulphate  of  platinum  and  24  per  cent, 
of  gelatin  and  water. 

We  now  come  to  the  most  important  and 
characteristic  property  of  gelatin,  which  is, 
that  of  combining  with  tannin,  and  upon 
which  the  art  of  tanning,  or  the  conversion 
of  skin  into  leather,  essentially  depends,  for 
the  true  skin  ( cutis )  of  animals  consists  of 
a  condensed  and  fibrous  form  of  organised 
gelatin,  and,  when  properly  prepared  and  im- 
mersed in  a  solution  of  vegetable  astringent 
matter  or  tannin,  it  becomes  gradually  pene- 
trated by  and  combined  with  it,  and  when 
dried  is  rendered  insoluble  and  durable.  The 
tannin  of  the  gall-nut  is  perhaps  that  which 
forms  the  most  insoluble  precipitate  in  gelati- 
nous solutions,  and  is  therefore  the  most  de- 
licate test  of  the  presence  of  gelatin ;  but,  as 
albumen  is  also  thrown  down  by  it,  the  absence 
of  the  latter  must  have  been  previously  ascer- 
tained. (See  Albumen.)  A  strong  infusion 
of  galls  occasions  a  precipitate  in  water  holding 
less  than  a  five-thousandth  part  of  gelatin  in 
solution,  and,  if  added  to  a  strong  solution 
of  gelatin,  it  throws  it  down  in  the  form  of 
a  curdy  precipitate,  more  or  less  dense  and 
coloured  according  to  the  greater  or  less  excess 
of  the  precipitant.  The  precipitated  compound 
is  insoluble  in  water,  dilute  acids,  and  alcohol, 
and  when  dried  becomes  hard  and  brittle,  but 
again  softens  and  acquires  its  former  appear- 
ance when  soaked  in  water :  it  may  be  termed 
tanno-gelatin.  When  tannin  is  added  to  a 
solution  of  gelatin,  the  latter  being  in  excess, 
and  especially  if  it  be  warm,  no  precipitate 
is  immediately  formed,  for  tanno-gelatin,  when 
recently  precipitated,  is  to  a  certain  extent 
soluble  in  liquid  gelatin.  Tanno-gelatin  does 
not  appear  to  be  a  definite  compound  ;  at  least 
it  is  difficult  to  obtain  it  as  such :  the  preci- 
pitate by  infusion  of  galls  consists,  when  care- 
fully dried,  of  about  40  per  cent,  of  tan  and  60 
of  gelatin.  When  obtained  by  other  astringents, 
such  as  oak-bark,  catechu,  and  kino,  it  differs 
in  the  relative  proportion  of  its  components 
and  in  its  other  characters,  and  often  contains 
extractive  matter.  According  to  Sir  H.Davy,* 
100  parts  of  calf-skin  thoroughly  tanned  by 
infusion  of  galls  increase  in  weight  64  parts  ; 
by  strong  infusion  of  oak-bark  34,  and  by 
weak  17;  by  concentrated  infusion  of  willow- 
bark  34,  and  by  dilute  15 ;  and  by  infusion 
of  catechu  19. 

Mr.  Hatchett's  researches  have  shewn  that 
gelatin  is  also  precipitated  by  the  varieties 

*  Philos.  Trans. 


of  artificial  tan,  and  that  the  compound  thrown 
down  resembles  in  its  leading  characters  the 
tanno-gelatin  of  natural  tan.  The  ultimate 
composition  of  gelatin  (pure  isinglass)  has 
been  quantitatively  determined  by  Gay  Lussac 
and  Thenard,  with  the  following  results  : — 


Nitrogen 
Carbon 


Oxygen 


Atoms. 

Equiv. 

Theory. 

Experiment. 

.  1 

14 

16.09 

16.998 

.  7 

42 

48.28 

47.881 

.  7 

7 

8.04 

7.914 

.  3 

24 

27.59 

27.207 

1 

87 

100.00 

100.000 

As  the  combining  proportion  of  gelatin  has 
not  been  accurately  ascertained,  its  equivalent 
number,  as  above  given,  is  open  to  doubt, 
but  it  is  probably  correct,  and  the  theoretical 
and  experimental  results  closely  correspond. 

(  W.  T.  Brandt.) 

GENERATION,  ORGANS  OF,  (Com- 
parative Anatomy). — Few  subjects  connected 
with  physiology  have  been  investigated  more 
assiduously  than  that  of  the  generation  of  ani- 
mals ;  and  in  none,  perhaps,  has  the  poverty  of 
our  knowledge  of  the  operations  of  nature  been 
more  conspicuously  exemplified.  In  studying 
many  functions  of  the  animal  economy,  the 
laws  of  chemistry  and  mechanics  have  been  suc- 
cessfully appealed  to  by  the  philosopher,  and 
their  application  to  the  operations  of  the  animal 
frame  satisfactorily  substantiated  ;  but  in  at- 
tempting to  explain  the  wonderful  process  by 
which  organized  bodies  are  perpetuated,  all  the 
resources  of  modern  science  have  been  found 
totally  inadequate  to  the  task,  and  we  are  still 
left  to  record  facts  and  observations  concerning 
the  structure  of  the  organs  appropriated  to  the 
propagation  of  animals,  without  being  in  any 
degree  able  to  connect  them  with  the  results  so 
continually  offered  to  our  contemplation.  In 
taking  a  general  survey  of  the  animal  kingdom, 
we  are  at  once  struck  with  the  infinite  variety 
of  forms  which  it  presents,  adapted  to  an  end- 
less diversity  of  circumstances,  and  might  expect 
to  meet  with  a  corresponding  dissimilarity  in  the 
organization  of  the  generative  apparatus  pecu- 
liar to  each :  no  such  dissimilarity,  however, 
exists  in  nature,  the  modes  of  reproduction 
conform  to  a  few  grand  types,  and  the  increasing 
complexity  of  parts,  apparent  as  we  ascend  to 
higher  classes,  which  it  will  be  our  business  to 
trace  in  this  article,  will  be  seen  to  depend 
rather  upon  modifications  in  the  arrangement 
of  secondary  structures  than  upon  any  deviation 
from  the  fundamental  organization  of  the  more 
immediate  agents. 

Without  entering  upon  any  discussion  con- 
cerning the  theories  which  have  from  time  to 
time  been  advocated  relative  to  spontaneous 
generation,  we  shall  divide  all  animals  as  re- 
lates to  the  generative  function  into  three  great 
classes,  grouping  together  such  as  are 

1st.  Fissiparous,  in  which  the  propagation  of 
the  species  is  effected  by  the  spontaneous  divi- 
sion of  one  individual  into  two  or  more,  pre- 
cisely resembling  the  original  being. 


ORGANS  OF  GENERATION. 


407 


2nd.  Gemmiparous,  in  which  the  young 
sprout  as  it  were  from  the  substance  of  the 
parent. 

3rd.  Oviparous,  producing  their  offspring 
from  ova  or  germs  developed  in  special  organs 
adapted  to  their  formation. 

Of  these  modes  of  reproduction  the  two  first 
are  confined  to  the  lowest  or  acrite  division  of 
the  animal  kingdom,  whilst  the  third  or  ovipa- 
r?Uo  type  is  common  to  all  other  classes. 

Fissiparous  generation  is  the  simplest  possi- 
ble, and  presupposes  a  corresponding  simpli- 
city of  structure  in  the  animals  which  propa- 
gate in  this  manner.  It  is  principally  confined 
to  the  Polygastric  animalcules,  most  of  which 
are  multiplied  by  the  spontaneous  separation  of 
an  individual  into  two  portions  precisely  resem- 
bling each  other,  and  capable  of  performing  all 
the  functions  which  originally  belonged  to  the 
undivided  creature.  Some  of  the  larger  species 
of  Trichoda  are  well  calculated  to  exhibit  to 
the  microscopic  observer  the  steps  by  which 
this  process  is  accomplished  :  the  animalcule, 
prior  to  its  division,  is  seen  to  become  slightly 
elongated,  and  a  tiansparent  line  is  gradually 
distinguishable,  indicating  the  course  of  the  in- 
tended fissure  ;  at  each  extremity  of  this  line  a 
contraction  of  the  body  is  speedily  observable, 
and  the  lateral  indentations  become  deeper 
and  deeper,  till  at  length  a  perfect  separation 
is  effected.  The  direction  in  which  this  divi- 
sion occurs  is  not  always  the  same  even  in 
the  same  species ;  thus,  instead  of  traversing 
the  shorter  axis  of  the  body  it  not  unfrequently 
assumes  a  longitudinal  or  oblique  direction, 
and  from  this  cause  it  is  not  unusual  to  find  the 
newly  divided  creatures  differing  materially  in 
appearance  from  their  adult  or  rather  conjoined 
form  ;  for  in  this  process  the  old  animalcules 
literally  become  converted  into  young  ones. 

In  some  of  the  more  complex  forms  of  Poly- 
gastrica  the  fissiparous  mode  of  generation  exhi- 
bits modifications  which  are  extremely  curious. 
In  the  beautiful  Vorticella,  whose  bell-shaped 
bodies  are  supported  on  long  and  exquisitely 
irritable  stems,  the  division  commences  at  the 
large  ciliated  extremity  of  the  animalcule,  from 
which  point  it  gradually  extends  in  a  longitudi- 
nal direction  towards  the  insertion  of  the  stem, 
dividing  the  body  into  two  equal  portions,  one 
or  both  of  which  becoming  speedily  detached 
from  the  pedicle,  might  easily  in  this  state  be 
mistaken  for  creatures  of  a  different  genus,  and 
have  in  fact  been  described  as  such  by  many 
authors.  The  new  animalcule,  when  thus 
deprived  of  its  pedicle,  is  seen  to  be  fur- 
nished with  cilia  at  the  opposite  extremity  to 
that  on  which  they  were  previously  found,  while 
from  the  other  end,  originally  the  mouth,  a  new 
foot-stalk  becomes  gradually  developed,  and  the 
creature  assumes  the  shape  proper  to  its  species. 
If  one  of  the  bells  remain  attached  to  the  pedi- 
cle, it  continues  to  perform  the  same  movements 
as  before  the  separation  of  the  new  animalcule  ; 
but  if  both  become  detached,  the  foot-stalk 
perishes. 

In  the  strangely  compound  symmetrical  bo- 
dies of  Gonium  a  provision  for  separation 
appears  to  be  made  in  the  detached  portions  of 


which  each  perfect  animal  is  apparently  com- 
posed. The  body  of  Gonium  pectorale  con- 
sists of  sixteen  minute  transparent  globes  of 
unequal  size,  arranged  in  the  same  plane. 
This  beautiful  animalcule  is  propagated  by 
a  separation  of  its  integrant  spherules,  the 
creature  dividing  into  four  portions  precisely 
similar  to  each  other,  and  composed  individually 
of  one  of  the  central  globules  united  to  three 
of  the  smaller  marginal  ones  ;  and  no  sooner  is 
the  division  accomplished  than  the  component 
globes  of  each  portion  increasing  in  number, 
the  new  animalcules  assume  the  dimensions 
and  appearance  of  that  of  which  they  originally 
formed  parts. 

In  the  Gonium  pulvinatum  the  fissiparous 
mode  of  generation  gives  origin  to  a  still  more 
numerous  progeny.  The  young  animalcule  is 
a  minute,  flat,  diaphanous  and  quadrangular 
membrane,  which  swims  through  the  fluid  in 
which  it  is  found  by  movements  sufficiently  in- 
dicative of  its  animal  nature  :  as  it  enlarges,  the 
surface  is  seen  to  become  marked  by  two  series  of 
parallel  lines  which  cross  each  other  at  right  an- 
gles and  divide  the  creature  into  smaller  squares, 
which  ultimately  separate  and  become  distinct 
representations  of  the  original  animalcule. 

Some  of  the  Nematoid  worms,  as  the  Nais, 
are  likewise  said  to  propagate  by  spontaneous 
division. 

Gemmiparous  generation. — This  mode  of  re- 
production, like  the  fissiparous,  is  confined  to 
the  lowest  tribes  of  animal  existence,  and  the 
creatures  which  propagate  in  this  manner  are 
unprovided  with  any  apparatus  specially  appro- 
priated to  generation.  The  young  appear  as 
gemmae  or  buds,  which  at  certain  periods  sprout 
from  the  homogeneous  parenchyma  which  com- 
poses the  body  of  the  parent,  and  these  buds  gra- 
dually assuming  the  form  of  the  original  by  a 
kind  of  vegetative  growth,  become  in  a  short 
time  capable  of  an  independent  existence.  The 
gemmiparous  type  of  the  generative  function 
is  met  with  through  a  wider  range  of  the  animal 
kingdom  than  the  last,  existing  under  modified 
forms  in  many  species  of  Polygastric  Infusoria, 
and  of  Polyps,  as  well  as  in  Sponges,  the  Cys- 
tiform  Entozoa,  and  probably  in  some  Acale- 
phae. 

It  is  in  the  Cystoid  Entozoa  that  we  find  it  in 
its  simplest  form.  In  the  Cysticercus  and  like- 
wise in  the  Ccenurus,  the  transparent  membra- 
nous bag  of  which  the  animal  consists  is  filled 
with  a  glairy  fluid,  in  which  occasionally  young 
hydatids  are  seen  floating  about.  These  young 
Cysticerci  in  the  earliest  period  of  their  forma- 
tion are  seen  to  pullulate  from  the  parietes  of 
the  parent  sac,  and  gradually  enlarging  they 
ultimately  separate  from  their  connexions,  be- 
coming detached  and  perfect  animals. 

Many  of  the  Polygastrica  are  multiplied  by 
a  similar  process,  of  which  the  Volvox  globator 
may  serve  as  an  illustration.  This  beautiful  ani- 
malcule is  a  minute  diaphanous  globe,  which 
under  the  microscope  is  generally  seen  to  con- 
tain a  variable  number  of  smaller  globules,  which 
are  the  young  :  these,  when  first  discoverable, 
are  .attached  to  the  inner  surface  of  the  parent, 
but  speedily  detaching  themselves  they  are 


408 


ORGANS  OF  GENERATION. 


found  rolling  loosely  within  the  body  of  the 
larger  animalcule,  effecting  their  rotatory  move- 
ments by  the  agency  of  cilia  of  extreme  minute- 
ness, which  under  a  good  microscope  are  seen 
to  cover  their  external  surface.  The  contained 
globules  having  attained  a  sufficient  maturity, 
the  parent  volvox  bursts,  and  thus  by  its  own 
destruction  allows  its  progeny  to  escape  from 
their  imprisonment.  The  multiplication  of 
these  animalcules  is  effected  with  considerable 
rapidity,  and  it  not  unfrequently  happens  that 
even  before  the  escape  of  the  second  generation 
the  gem  mules  of  a  third  may  be  observed  within 
their  bodies,  which  in  like  manner  advancing 
through  similar  stages  of  development  will  ter- 
minate by  their  birth  the  existence  of  their 
parent.* 

It  would  appear  from  the  observations  of 
Professor  Grant,  that  in  the  sponges,  notwith- 
standing their  different  form,  the  process  of  re- 
production is  entirely  similar.  In  these  curious 
animals  the  gemmules  are  developed  in  the 
substance  of  that  living  parenchyma  which 
coats  their  porous  skeletons,  and  when  mature 
are  expelled  through  the  fcecal  orifices  to  com- 
mence an  independent  existence.  When  sepa- 
rated from  the  parent  sponge,  these  gemmules, 
like  those  of  the  volvox,  are  ciliated  over  a  great 
portion  of  their  surface,  and  being  thus  endowed 
with  a  power  of  locomotion,  are  enabled  to 
swim  to  a  considerable  distance  in  search  of  a 
situation  adapted  to  their  future  growth,  until 
having  at  length  selected  a  permanent  support, 
they  become  attached,  and  developing  within 
themselves  the  spicular  or  horny  skeleton  pecu- 
liar to  their  species,  they  gradually  assume  the 
porous  texture  and  particular  character  of  the 
sponge  from  which  they  were  produced. 

But  it  is  in  the  gelatinous  Polypes  that  we 
meet  with  the  most  perfect  forms  of  gemmi- 
ferous propagation  :  of  this  the  Hydra  viridis, 
orfresh-water  polype,  affordsan  interesting  illus- 
tration, and  from  the  facility  with  which  it  may 
be  procured  and  examined  by  glasses  of  very 
ordinary  powers,  it  is  well  calculated  to  illus- 
trate the  mode  of  generation  which  we  are  at 
present  considering.  The  body  of  this  simple 
polype  is  transparent,  and  under  the  microscope 
appears  to  be  entirely  made  up  of  translucent 
granules,  without  any  trace  of  internal  appara- 
tus appropriated  to  reproduction.  The  gem- 
mules by  which  it  is  propagated  sprout  from 
some  part  of  the  surface,  appearing  first  as  mere 
gelatinous  excrescences,  but  gradually  enlarging 
they  assume  the  form  of  their  parent,  acquiring 
similar  filamentary  tentacles  and  a  gastric 
cavity  of  the  same  simple  structure.  As  long 
as  the  junction  between  the  polype  and  its  off- 
spring continues,  both  seem  to  enjoy  a  commu- 
nity of  being,  the  food  caught  by  the  original  one 
being  destined  for  the  nourishment  of  both  ;  but 
at  length,  the  newly-formed  animal  having  at- 
tained a  certain  bulk,  and  become  capable  of 
employing  its  own  tentacles  for  the  prehension 
of  food,  detaches  itself  with  an  effort,  and  as- 

*  [Some  physiologists,  however,  refer  the  genera- 
tion of  this  creature  to  the  fissiparous  mode.  See 
the  succeeding  article. — En.] 


sumes  an  independent  existence.  This  mode 
of  multiplication  is  exceedingly  rapid,  a  few 
hours  sufficing  for  the  perfect  developement  of 
the  young  creature ;  and  not  unfrequently  even 
before  its  separation,  another  gemmule  may  be 
observed  emerging  from  the  newly-formed 
polype,  soon  to  exhibit  the  same  form  and  ex- 
ercise the  same  functions  as  the  parent  from 
which  it  sprouts. 

The  propagation  of  some  of  the  lithophytour 
polypes  resembles  that  of  the  hydra,  the  young 
being  produced  from  buds  or  gemmules,  which 
sprout  from  the  living  investment  of  their  cal- 
careous skeleton.  Such  are  the  Fungia,  in 
which  the  young  are  at  first  pedunculated,  and 
fixed  to  the  laminae  upon  the  upper  surface  of 
the  mass  from  which  they  spring ;  in  this  state 
they  might  readily  be  mistaken  for  solitary 
Caryophyllia,  but  in  time  they  separate  from 
the  parent  stock,  and  loosing  the  pedicle  which 
originally  supported  them,  they  assume  the 
form  of  their  species. 

Oviferous  generation. — In  the  third,  and  by 
far  the  most  numerous  division  of  the  animal 
kingdom,  the  young  are  derived  from  ova  or 
eggs,  in  which  the  germ  of  the  future  being  is 
evolved,  and  from  which  the  young  animals 
escape  in  a  more  or  less  perfect  state. 

It  will  be  seen  that  the  ovum  which  gives 
birth  to  all  the  higher  animals  differs  essentially 
from  the  gemma  furnished  by  the  gemmiferous 
classes ;  in  the  gemmiferous  type  the  bud  or 
offshoot  of  the  parent  appears  by  a  kind  of 
vegetative  evolution  to  assume  the  proportions 
and  functions  of  the  original  from  which  it 
sprang.  The  ovum  we  would  define  as  a 
nidus,  containing  not  only  the  germ  of  the 
future  animal,  but  a  sufficient  quantity  of  nu- 
tritious matter,  serving  as  a  pabulum  to  the 
embryo  during  its  earliest  state  of  existence, 
and  supplying  the  materials  for  its  growth  until 
sufficiently  mature  to  derive  them  from  other 
sources.  We  have  already  shewn  that  in  the 
fissiparous  and  gemmiferous  animals  there  is 
no  necessity  for  any  special  generative  appa- 
ratus, but  in  the  oviferous  classes  we  find,  for 
the  most  part,  a  distinct  system,  more  or  less 
complicated  in  structure,  in  which  the  repro- 
ductive ova  are  developed  and  matured.  It 
must  be  confessed,  however,  that  in  the  present 
state  of  our  knowledge  upon  this  subject  we 
are  not  prepared  to  state  how  far  the  existence 
of  a  generative  system  is  exclusively  confined 
to  the  ovigerous  type.  We  are  well  aware 
that  many  authors  describe  generative  canals 
to  exist  in  several  of  the  polypiferous  tribes, 
although  the  reproductive  germs  produced  from 
them  resemble  in  their  ciliated  organs  of  pro- 
gression and  mode  of  development  the  gem- 
mules of  less  elaborately  organized  polypes; 
yet,  on  the  other  hand,  as  we  have  abundant 
evidence  to  prove  that  such  polypes  as  have  the 
ovigerous  canals  most  distinctly  formed,  as  the 
Actinias  for  instance,  produce  their  young  per- 
fectly organized  and  evidently  developed  from 
true  ova,  we  are  content,  in  the  present  state  of 
our  knowledge  upon  this  subject,  to  regard  the 
presence  of  generative  canals  as  co-existent 
with  ovigerous  generation,  and   shall  leave 


ORGANS  OF  GENERATION. 


409 


future  observations  to  determine  more  accu- 
rately the  mode  of  reproduction  in  the  corti- 
ciferous  polypes,  -which  is  a  subject  at  present 
involved  in  much  contradiction  and  obscurity. 

Taking  this  view  of  the  subject,  we  find, 
upon  cursorily  glancing  over  the  ovigerous 
classes  of  animals,  that  important  modifications 
of  structure  in  the  generative  system  render 
further  classification  necessary.  In  the  lower 
forms,  ovigerous  organs  only  have  been  dis- 
covered, in  which  the  ova  are  secreted,  and 
when  matured,  escape  from  the  body,  fit  in 
every  respect  for  the  production  of  a  new 
animal.  In  other  instances,  in  addition  to  the 
apparatus  immediately  appropriated  to  the  de- 
velopement  of  the  ova,  we  find  a  superadded 
portion  destined  to  furnish  a  secretion  which  is 
essential  to  their  fertility,  forming  an  apparatus 
of  impregnation.  Sometimes  the  impregnating 
organs  are  found  in  every  individual,  appended 
to  the  ovigerous  parts,  rendering  each  creature 
sufficient  for  the  impregnation  of  its  own  ova : 
in  other  instances,  although  each  animal  pos- 
sesses both  ovigerous  and  impregnating  or- 
gans, the  cooperation  of  two  individuals  or  more 
is  necessary  to  fertility ;  and  in  other  cases 
again,  the  apparatus  which  furnishes  the  ova, 
and  that  destined  to  the  production  of  the  im- 
pregnating fluid,  are  found  in  distinct  indivi- 
duals, distinguished  by  the  appellations  of 
male  and  female :  we  shall  accordingly  di- 
vide all  oviparous  animals  into  the  following 
groups : — 

1.  Such  as  are  provided  with  ovigerous 
organs  only. 

2.  Animals  having,  in  addition  to  the  ovige- 
rous apparatus,  a  glandular  structure,  the 
secretion  of  which  is  probably  subservient  to 
the  fertility  of  the  ova. 

3.  Ovigerous  and  impregnating  organs,  co- 
existent in  each  individual,  but  the  cooperation 
of  two  or  more  needful  for  mutual  impregna- 
tion. 

4.  The  ovigerous  and  impregnating  appa- 
ratus existing  in  distinct  individuals. 

First  Division. — Animals  in  which  ovigerous 
organs  only  have  been  distinctly  recognized. 

It  would  seem  from  the  observations  of 
Ehrenberg  that  some  of  the  Polygastrica  be- 
long to  this  division,  although  the  exact  nature 
of  the  generative  system  in  such  species  remains 
still  a  matter  of  uncertainty.  In  the  Kolpoda 
Cucullus  the  spawn  consists  of  a  loose  mass 
of  ova,  connected  by  delicate  filaments,  from 
which  the  young  are  gradually  evolved  after 
their  extrusion  from  the  parent  animalcule,  and 
some  of  the  parenchymatous  Entozoa  appear 
to  be  similarly  circumstanced. 

In  the  Acalepha;,  at  least  in  such  as  have 
been  most  attentively  examined,  the  generative 
system  conforms  to  the  type  at  present  under 
consideration.  From  the  researches  of  Gaede 
and  Eysenhardt  it  appears  that  the  ovaria  are 
four  in  number,  disposed  in  a  cruciform  manner 
upon  the  dorsal  aspect  of  the  body  or  that 
which  is  opposite  to  the  mouth.  These  ovaria, 
which  at  certain  seasons  of  the  year  are  re- 
markably  distended    and    often  beautifully 

VOL.  II. 


coloured,  open  into  the  interior  of  the  stomach- 

The  young  Medusae  are  hatched  in  the  ovaria, 
and  afterwards  escaping  into  the  alimentary 
canals  excavated  in  the  substance  of  the  body, 
acquire  in  that  situation  a  very  perfect  state 
of  development,  and  are  ultimately  excluded 
through  the  oral  aperture,  or  in  the  llhizosto- 
matous  species  through  the  ramified  canals  of 
the  pedicle. 

In  the  fleshy  polypes  (Actinia?)  the  ovigerous 
system  consists  of  long,  convoluted  filiform 
tubes,  contained  between  the  stomach  and  the 
parietes  of  the  body,  and  separated  by  partitions 
which  divide  that  space  into  compartments. 
These  tubes  are  attached  by  a  delicate  mesen- 
tery, and  according  to  Spix  open  in  an  irregular 
manner  into  the  digestive  cavity,  into  which 
the  ova  escape.  The  period  or  mode  in  which 
the  eggs  are  hatched  is  unknown,  but  that  the 
young  escape  fully  formed  and  in  every  point 
resembling  their  parent  through  the  stomachal 
orifice  is  attested  botli  by  Dicquemare  and 
Blainville.* 

The  different  forms  of  Echinodermata  pre- 
sent a  similar  simple  arrangement  of  the  gene- 
rative apparatus.  In  the  Asteriadcs  each  ray 
is  furnished  with  two  clusters  of  short  ovigerous 
tubes,  which  are  closed  at  one  extremity,  but 
open  at  the  other  into  a  cavity  common  to  each 
group.  These  organs  open  by  a  series  of  aper- 
tures placed  around  the  circumference  of  the 
mouth  at  the  base  of  each  ray.  In  the  spring 
these  ovaria  are  distended  with  eggs  of  a 
reddish-brown  colour,  which  are  expelled  in 
clusters  and  left  upon  the  beach  exposed  to 
the  influence  of  the  sun,  where  they  are  ulti- 
mately hatched.f 

The  radiated  type  of  structure  is  likewise 
manifest  in  the  disposition  of  the  generative 
organs  of  the  Ecbinida? :  in  these  the  ovaria 
are  never  single  cr  simply  bilobed,  but  are  at 
least  four  in  number,  or,  as  is  generally  the 
case,  five.  Each  ovigerous  organ  consists  of 
a  simple  dilated  sacculus,  which  at  certain 
seasons  is  distended  with  ova,  and  at  such 
times  in  some  species,  as  in  the  edible  Echinus, 
the  eggs  are  sought  after  as  an  article  of  food. 
The  ovaria  open  externally  by  a  corresponding 
number  of  simple  apertures,  which  are  placed 
around  the  anal  orifice  when  it  is  central,  but 
otherwise  are  considerably  removed  from  this 
point.  Nothing  analogous  to  a  male  apparatus 
has  been  detected  in  the  Echinida.  The  eggs 
are  deposited  in  spring  in  the  recesses  of  rocks 
or  among  the  fucus  which  covers  them  ;  and 
before  they  are  hatched  the  young  may  be  dis- 
covered in  the  interior  partially  covered  with  a 
calcareous  shell,  the  rest  of  the  integument 
still  remaining  membranous. 

*  Spix  and  Delle  Chiajc  assert  that  there  are 
other  filiform  tubes  mixed  up  with  the  ovarian  ducts, 
which  they  regard  as  the  testes,  but  neither  the 
observations  of  other  authors  nor  our  own  exami- 
nations confirm  this  view  of  the  subject. 

t  Tischer  and  Spix  describe  a  singular  flexuous 
intestiniform  organ  which  is  found  upon  the  dorsal 
aspect  of  the  stomach  as  a  male  apparatus,  and 
Blainville  considers  this  part  as  in  some  degree 
connected  with  generation. 

2  E 


410 


ORGANS  OF  GENERATION. 


The  Holothuridse  present  in  the  elongated 
form  of  their  bodies  an  evident  approximation 
to  the  annulose  type  of  structure,  and  a  propor- 
tionate concentration  of  the  generative  system  ; 
in  these  we  find  but  one  ovary  floating  loosely 
in  the  visceral  cavity,  and  composed  of  numerous 
very  long  cceca,  which  terminate  by  a  single 
orifice  placed  on  the  median  line,  near  the  oral 
extremity  of  the  animal.*  The  eggs  when  dis- 
charged are  connected  into  masses  composed 
of  long  strings  of  ova,  but  the  mode  of  their 
development  is  but  little  known. 

Although  from  the  relations  of  the  Mollus- 
cous division  of  the  animal  kingdom  we  might 
infer  that  a  more  elevated  type  of  structure 
would  characterize  their  organs  of  reproduction, 
the  present  state  of  our  knowledge  of  the 
anatomy  of  these  creatures  compels  us  to  arrange 
the  lowest  orders  of  that  extensive  class  with 
those  tribes  which  only  possess  an  ovigerous 
system ;  for  although  an  androgynous  confor- 
mation is  presumed  by  many  to  exist  in  all 
Bivalves,  the  presence  of  any  superadded  im- 
pregnating portion  has  not  yet  been  pointed 
out,  and  even  the  course  of  the  ova  in  their 
passage  from  the  ovarian  cavity  remains  a  mat- 
ter of  speculation.    In  the  Conchiferous  order, 
from  causes  sufficiently  obvious  when  we  con- 
sider the  peculiar  structure  of  the  animals 
which  compose   it,  the  full  development  of 
their  numerous    ova  could  not  be  accom- 
plished in  the  ovary  itself,  which  occupies  a 
large  portion  of  the  body,  as  any  material  in- 
crease of  bulk  produced  from  this  cause  would 
materially  interfere  with  the  closing  of  the 
shell ;  at  an  early  period,  therefore,  the  ova 
are  transferred  from  the  nidus  in  which  they 
were  formed  to  the  branchial  fringes,  between 
the  lamina;  of  which  they  perfect  their  growth, 
and  are  fully  exposed  to  the  influence  of  the 
element  around  them.    Oken  traced  a  canal 
through  which  he  supposed  the  ova  to  be  con- 
veyed directly  from  the  ovaria  to  the  gills  ;f 
but  notwithstanding  his   observations  Carus 
contends  J  that  the  eggs  pass  into  the  stomach 
through  one  of  the  openings  hitherto  considered 
as  belonging  exclusively  to  the  biliary  ducts, 
whence  they  are  evacuated  through  the  mouth 
and  conveyed  into  the  openings  of  the  gills 
by  the  water  which  flows  between  the  pallial 
laminae  from  before  backwards,  and  ultimately 
escape  by  two  canals  which  open  below  the  anal 
tubes. 

In  the  Tunicata,  and  also  in  those  forms  of 
the  Gasteropodous  Mollusca  which  most  nearly 
approximate  the  Conchifera  in  the  details  of 
their  organization,  the  ovary  is  imbedded  in 
the  substance  of  the  liver,  and  the  ova  are  dis- 

*  Here,  also,  Blainville  conjectures  that  there  is 
a  supplementary  impregnating  portion,  but  it  is 
evident  that  in  a  treatise  like  the  present  it 
would  be  worse  than  useless  to  recapitulate  the 
surmises  of  authors  upon  subjects  only  capable  of 
solution  by  positive  demonstration,  and  we  shall 
therefore  endeavour  rather  to  adhere  strictly  to  the 
narration  of  what  is  clearly  established  by  observa- 
tion, than  to  indicate  what  theory  or  analogy  would 
lead  us  to  suspect. 

t  Goetting,  gel.  Anzeigeu,  1806. 

}  Introduct.  to  Comp.  Anat. 


charged  through  a  simple  duct,  unprovided 
with  any  appendage  which  can  be  looked  upon 
as  a  male  apparatus.  It  is  true,  indeed,  that 
in  all  these  cases  the  walls  of  the  oviduct  may 
themselves  furnish  a  fertilizing  fluid,  and  by 
many  physiologists  they  are  supposed  thus  to 
supply  the  want  of  male  parts ;  such  an  hypo- 
thesis, however,  is,  to  say  the  least  of  it, 
entirely  gratuitous  ;  but  as  it  is  more  our  busi- 
ness to  trace  the  development  of  organs  than 
the  modes  in  which  their  deficiency  may  be 
supplied,  we  are  content  to  leave  the  question 
without  further  discussion  in  this  place. 

Second  Division. — Animals  provided  with 
ovigerous  organs  combined  with  an  addi- 
tional secreting  structure,  probably  sub- 
servient to  the  fertilization  of  the  ova. 
In  this  type  of  the  generative  system  it  must 
be  obvious  that  the  function  attributed  to  the 
superadded  portion  is  by  no  means  indubitably 
substantiated,  the  opinions  of  physiologists 
relating  to  its  office  being  rather  based  upon 
analogical  reasoning  than  supported  by  direct 
evidence ;  and,  in  fact,  some  authors  deny 
entirely  that  a  necessity  for  the  impregnation 
of  the  ova  is  more  evident  in  this  division  than 
in  the  last.  Nevertheless,  although  it  is  im- 
possible distinctly  to  prove  the  identity  in 
function  between  the  appended  portion  and 
the  testis  of  higher  forms  of  organization,  the 
evidence  afforded  from  the  position  which  it 
invariably  occupies,  and  from  the  considera- 
tion of  the  parts  connected  with  generation  in 
dioecious  animals  to  which  we  are  insensibly 
conducted  by  this  species  of  Hermaphrodism, 
is  sufficiently  cogent  to  warrant  our  application 
of  the  term  ovarium  to  the  nidus  wherein  the 
ova  are  produced,  and  to  justify  us  in  designa- 
ting the  accessory  organ  as  a  testis  or  apparatus 
for  impregnation. 

The  Tsenioid  Sterelmintha  furnish  us  with 
one  of  the  simplest  examples  of  this  arrange- 
ment of  the  generative  organs.  In  the  long 
and  tape-like  bodies  of  these  Entozoa  each 
segment,  with  the  exception  of  the  smaller  ones 
near  the  head,  possesses  distinct  ovigerous  and 
impregnating  structures.  The  female  part  of 
the  apparatus  occupies  the  centre  of  the  joint, 
and  consists  of  lateral  tubes  ramifying  from  a 
centra!  canal,  which  at  times  may  be  seen  to 
be  full  of  minute  granular  ova.  From  these 
ovigerous  canals  a  duct  issues,  which  commu- 
nicates with  the  lateral  pore  and  receives  before 
its  termination  two  delicate  tubes,  recognizable 
under  the  microscope  as  dark  lines  imbedded 
in  the  pulpy  segment,  and  which  may  be  pre- 
sumed to  furnish  an  impregnating  secretion. 

In  the  Rotifera,  or  wheel-animalcules,  the 
female  apparatus  consists  of  two  long  and 
comparatively  wide  sacculi,  in  which  the  ova 
are  developed  ;  these  open  at  the  anal  orifice, 
and  receive  near  this  point  two  narrow  cceca, 
which,  as  in  the  last  case,  may  secrete  a  fer- 
tilizing fluid,  serving  to  impregnate  the  eggs 
prior  to  their  expulsion.  The  ova  of  these 
minute  creatures,  before  the  escape  of  the 
young,  are  exceedingly  beautiful  subjects  for 
the  microscope,  the  wheels  of  the  embryo 


ORGANS  OF  GENERATION. 


411 


being  easily  distinguished  in  rapid  action 
through  the  pellucid  coverings  of  the  egg. 

In  the  Cirrhopoda  we  have  most  probably 
an  example  of  this  mode  of  generation,  pre- 
suming, that  is,  that  the  opinions  of  Cuvier 
upon  this  subject  are  correct.  These  opinions, 
it  is  true,  have  been  disputed  by  various 
authorities,  as  will  be  evident  on  reference 
to  the  article  Cirrhopoda  ;  but  their  correct- 
ness has  been  so  fully  supported  by  the 
dissections  of  John  Hunter,  recently  given 
to  the  world,*  that  it  seems  best  at  least  to 
pause  before  repudiating  the  conclusions  to 
which  these  great  anatomists,  unacquainted 
with  the  labours  of  each  other,  were  indivi- 
dually conducted.  In  the  Cirripeds  the  ovaria 
are  two  in  number,  placed  on  each  side  of 
the  stomach  ;  the  two  oviducts  which  proceed 
from  these  unite  to  form  a  single  elongated 
tube,  the  parietes  of  which  are  thick  and 
apparently  glandular.  It  is  evident  that  in  this 
case  the  walls  of  the  common  canal,  or  ovipo- 
sitor as  it  is  usually  termed,  may  serve  to 
secrete  a  seminal  fluid,  impregnating  the  eggs 
at  the  period  of  their  extrusion ;  and  such, 
in  the  opinion  of  the  authors  above  mentioned, 
is  a  part  of  its  office. 

Third  Division. —  Ovigerous  and  impreg- 
nating organs  co-existent,  but  the  co- 
operation of  two  individuals  necessary 
tor  mutual  impregnation. 

This  arrangement  of  the  generative  system 
occurs  in  some  of  the  Parenchymatous  Entozoa, 
in  the  Annelida,  and  also  in  the  Pteropod  and 
some  Gasteropod  Mollusca.  Some  of  the 
Entozoa,  as  Fasciola  and  Planaria,  furnish 
the  simplest  examples  of  this  hermaphrodite 
condition.  In  these  creatures  the  male  organs 
consist  of  spermatic  coeca,  communicating  with 
a  minute  extensible  penis,  which  is  placed 
behind  the  oral  sucker.  Near  the  penis  a 
small  orifice  is  seen,  leading  to  the  ovigerous 
canals,  which  have  no  communication  with 
the  impregnating  apparatus ;  and  the  copula- 
tion of  two  individuals  is  thus  indispensable 
to  a  reciprocal  fertilization  of  the  ova. 

Those  of  the  Annelida  in  which  the  gene- 
rative system  is  best  understood  are  androgy- 
nous, and  mutually  impregnate  each  other, 
although  it  is  probable  that  in  the  tubicolous 
genera,  which  are  immoveably  fixed  to  the 
same  spot,  and  almost  deprived  of  locomotion, 
each  individual  may  in  itself  be  sufficient  for 
reproduction. 

In  the  Abranchiate  and  Dorsibranchiate 
Annelida  the  male  apparatus  is  composed  of 
several  pairs  of  secreting  bodies,  arranged  on 
each  side  of  the  mesial  plane,  those  of  the 
same  side  communicating  with  each  other  by 
a  common  vas  deferens.  In  the  Leech  the 
vasa  deferentia,  which  convey  the  secretion  of 
the  numerous  testicular  masses,  terminate  in 
a  long  protractile  tubular  penis,  and  at  a  short 
distance  behind  this  the  opening  which  leads 

*  Catalogue  of  the  Physiological  Series  of  Com- 
parative Anatomy  contained  in  the  Hunterian 
Collection,  vol.  i. 


to  the  female  parts  may  be  discovered.  These 
latter  consist  of  a  simple  uterine  sacculus,  or 
receptacle  for  the  ova,  to  which  two  minute 
ovaries  are  appended.  The  congress  of  two 
individuals  is  effected  by  the  reciprocal  in- 
troduction of  the  organs  of  intromission  into 
the  vulva;.  In  the  Earthworm  and  Nais  the 
intromittent  apparatus  is  deficient,  so  that 
some  authors  have  even  doubted  that  the 
process  of  copulation,  which  is  undeniably 
essential  to  fecundity,  does  more  than  stimulate 
each  individual  to  self-impregnation.  In  the 
Earth-worm,  as  well  as  in  Arenicola  and 
Aphrodita,  the  ova,  after  escaping  from  the 
ovaria,  are  retained  in  the  cellular  meshes 
which  surround  the  alimentary  canal,  in  which 
they  are  not  unfrequently  hatched,  the  young 
being  most  probably  expelled  through  a  tubular 
aperture  at  the  posterior  extremity  of  the  body. 

As  regards  the  generative  system,  the  Pte- 
ropod Mollusca  approximate  the  more  complex 
type  seen  in  the  Gasteropoda.  In  Clio  borealis, 
the  ovary,  which  is  partially  enveloped  by  the 
liver,  gives  off  a  slender  duct,  which,  after 
a  short  course,  plunges  into  a  glandular  tube  ; 
this,  becoming  gradually  narrower,  terminates 
in  a  round  sac  placed  on  the  left  side  of  the 
head,  where  it  opens  externally  :  near  this 
point  is  the  penis,  or  organ  of  intromission, 
communicating  with  a  small  sacculus,  by 
which  the  male  secretion  is  probably  furnished. 


Fig.  200. 


Testis  of  Helix. 


The  most  complicated  forms  of  this  species 
of  hermaphrodism  are  met  with  in  the  Gas- 
teropod division  of  Mollusca,  existing  through- 
out the  Nudibranchiate,  Tectibianchiate,  In- 
ferobranchiate,  and  Ilcteropod  orders,  as  well 
as  in  those  pulmonary  genera  which  are  un- 
provided with  a  calcareous  operculum.  In 
all  these  cases  the  testis  is  single  and  divided 
into  lobuli,  connected  together  by  the  divisions 
of  the  vas  deferens  so  as  to  exhibit  a  racemose 
arrangement,  and  each  lobule,  on  minute  in- 
spection, is  found  to  consist  of  little  peduncu- 
lated vesicles  (jig.  200).  A  slender  vas  defe- 
rens conducts  the  secretion  of  this  testicle  to 
the  base  of  an  intromittent  organ  of  a  most  sin- 
gular description  ;  this  is  a  muscular  tube  of 
great  length,  which,  when  not  in  use,  is  in- 
verted and  concealed  within  the  body,  but  ca- 
pable of  protrusion  at  the  will  of  the  animal. 
The  female  portion  of  this  system  is  composed 
of  one  ovary,  provided  with  an  ample  and 
tortuous  oviduct,  which  serves,  indeed,  as  a 
kind  of  uterus  or  egg  receptacle,  wherein  the 

2  e  2 


412 


ORGANS  OF  GENERATION. 


ova  are  retained  until  ripe  for  extrusion. 
Near  the  termination  of  this  oviduct  are  placed 
several  additional  appendages,  some  of  which 
are  apparently  destined  to  furnish  an  invest- 
ment for  the  ova,  whilst  one,  which  is  con- 
stantly present,  is  probably  a  reservoir  for  the 
seminal  fluid  required  to  fertilize  the  eegs 
as  they  are  expelled.    (See  Gasteropoda.)" 

The  external  parts  are  so  disposed  that 
during  the  copulation  of  two  individuals  the 
male  organ  of  each  is  introduced  into  the 
orifice  leading  to  the  female  apparatus  of  the 
other,  both  thus  impregnating  and  being  im- 
pregnated at  the  same  time. 

In  Lymnai/s  stagnalis  we  have  a  curious 
exception  to  this  mode  of  copulation,  for  in 
this  animal  the  sexual  organs  are  so  placed 
that  mutual  impregnation  is  impossible,  and 
accordingly  fecundation  is  accomplished  by  a 
combination  of  individuals,  each  of  which 
performs  the  office  of  a  male  to  another,  while 
to  a  third  it  acts  the  part  of  a  female,  and  long 
strings  of  them  are  often  seen  thus  united. 

Fourth  Division. — Sexes  distinct,  that  is, 
the  ovigerous  and  impregnating  organs 
placed  in  separate  individuals. 
This  type  of  the  reproductive  apparatus 
extends  through  a  wide  range  of  animals,  and 
is  found  in  a  great  number  of  classes  utterly 
dissimilar  in  outward  form  and  internal  struc- 
ture ;  so  that,  in  order  to  give  a  connected  view 
of  the  comparative  organization  of  the  parts 
of  generation,  we  shall  be  unavoidably  com- 
pelled to  group  together  animals  widely  sepa- 
rated by  the  laws  of  zoological  arrangement. 
Feeling,  however,  that  by  so  doing  we  shall 
lay  before  our  readers  a  much  more  easily 
intelligible  comparison  of  the  organs  belonging 
to  our  subject,  we  shall  not  scruple  to  bring 
together,  in  one  view,  analogous  forms  of  the 
generative  apparatus,  in  whatever  classes  they 
may  be  found.  Animals  in  which  the  sexes 
are  distinct  may  be  divided  into  three  classes ; 
the  first  including  such  as  are  oviparous,  the 
second  embracing  the  ovo-viviparous  orders, 
while  the  third  will  comprehend  the  strictly 
viviparous  animals.  It  will  be  seen  that 
the  terms  here  employed  have  been  used 
from  time  immemorial,  but  nevertheless  in  a 
widely  different  sense  to  that  in  which  the 
present  state  of  our  knowledge  sanctions 
their  application.  To  us  it  appears  that  we 
ought  to  regard  all  creatures  as  ovipa- 
rous whose  offspring,  at  the  period  of  their 
escape  from  the  ovum,  are  sufficiently  mature 
to  admit  of  their  independent  existence.  In 
the  ovo-viviparous  division,  on  the  contrary, 
the  ova  are  hatched  and  the  embryo  expelled 
at  an  early  period  of  its  formation  ;  the  embryo 
is  thus  born  in  an  extremely  imperfect  state, 
the  materials  for  its  future  developement  being 
supplied  by  the  mammary  secretion  of  the 
parent ;  such  is  the  case  with  all  the  marsupial 
orders.  In  the  vivipara  the  earliest  stages  of 
growth  are  precisely  similar  to  those  which 
mark  the  progress  of  evolution  in  the  ovi- 
parous type,  and  the  provisions  made  for 
the  nourishment  of  the  rudimentary  being  in 


every  respect  analogous ;  the  great  distinction 
consists  in  the  subsequent  maturation  of  the 
embryo  within  a  uterine  cavity,  and  the  forma- 
tion of  a  placenta,  which  characterizes  the 
highest  form  of  mammiferous  animals. 

The  oviparous  classes,  which  form  by  far 
the  most  numerous  division,  produce  their 
young  from  ova,  in  which  the  germs  of  the 
future  beings  are  developed  for  the  most  part 
subsequent  to  the  expulsion  of  the  egg  from 
the  body  of  the  parent.  In  this  case  the 
ovum  necessarily  contains  a  sufficient  store  of 
nourishment  for  the  support  of  the  embryo 
during  the  whole  period  of  foetal  life,  at  the 
termination  of  which  it  is  produced  in  a  suffi- 
ciently advanced  stage  of  its  growth  to  render 
it  capable  of  independent  existence.  It  will 
readily  be  perceived  that  under  this  division 
we  include  many  animals  which,  according 
to  the  old  meaning  of  the  terms,  were  looked 
upon  as  ovo-viviparous  or  viviparous  in  their 
mode  of  reproduction  ;  a  distinction  which,  as 
the  words  have  been  hitherto  applied,  appears 
to  the  writer  by  no  means  sufficiently  grounded 
upon  physiological  views  to  admit  of  its  conti- 
nuance. It  is  certainly  very  true  that  some  ani- 
mals included  in  this  division  are  found  to  pro- 
duce their  young  in  a  living  state  ;  but  the  mere 
hatching  of  the  egg  within  the  oviductus  of 
the  mother,  instead  of  subsequent  to  its  ex- 
pulsion, is  not  a  circumstance  of  sufficient 
importance  to  be  regarded  as  constituting 
another  type  of  the  generative  process,  more 
especially  as  such  an  occurrence  is  entirely 
fortuitous,  observation  having  proved  that  the 
same  animal  at  one  time  produces  its  young  alive 
and  at  another  in  the  egg  state,  in  obedience 
to  circumstances  connected  with  food,  tem- 
perature, or  confinement.  With  this  extension 
of  the  term,  oviparous  animals  in  which  the 
sexes  are  distinct  will  be  found  in  many  classes 
belonging  to  the  diploneurose,  cyclogangliate, 
and  vertebrate  divisions  of  the  animal  kingdom, 
combined  with  modifications  in  the  structure 
and  arrangement  of  the  generative  apparatus, 
which  it  will  be  our  business  to  trace. 

The  earliest  appearance  of  this  type  is  found 
in  the  cavitary  Entozoa  (Coelelmintha),  and  the 
sexual  organs,  both  in  the  male  and  female 
of  these  creatures,  may  be  regarded  as  ex- 
hibiting the  greatest  possible  simplicity  of 
structure,  consisting  merely  of  secreting  tubes, 
which  in  one  sex  produce  the  seminal  fluid, 
in  the  other  develope  the  ova.  The  seminal 
organ,  or  testis  of  the  male,  is  generally  a 
single  tube  of  extreme  length  and  tenuity, 
winding  in  large  folds  around  the  alimentary 
canal,  and  occupying  a  large  portion  of  the 
abdominal  cavity ;  when  unravelled,  its  length 
is  found  to  be  many  times  that  of  the  animal ; 
at  one  extremity  it  dwindles  down  to  a  filament 
of  the  utmost  tenuity,  which  floats  loosely 
in  the  juices  of  the  body,  whilst  at  the  op- 
posite end  it  terminates  in  a  prolonged  tubular 
penis,  or  organ  of  intromission,  placed  near 
the  anal  orifice.  In  the  females  of  some 
species,  as  in  Ascaris,  the  ovigerous  system 
is  composed  of  two  tubes,  each  exceeding  in 
length  and  tortuosity  the  seminal  vessel  of  the 


ORGANS  OF  GENERATION. 


413 


male,  and  measuring  in  some  cases  upwards 
of  six  feet.  These  tubes,  after  becoming  con- 
siderably increased  in  size  so  as  to  form  a 
kind  of  receptacle  for  the  ova  which  they 
generate,  unite  prior  to  their  termination  in 
the  vulva,  the  aperture  of  which  is  found  upon 
the  ventral  surface  of  the  body  at  about  one 
third  of  its  length  from  the  anterior  extremity. 
In  Strongylus  the  ovarian  tube  is  single,  and 
its  orifice  nearer  to  the  mouth.  In  many 
species,  as  Filaria,  the  young  are  produced 
alive,  the  ova  being  hatched  in  the  oviduct, 
a  sufficient  proof  of  internal  impregnation 
having  been  accomplished. 

The  Myriapoda,  in  every  part  of  their  struc- 
ture, form  the  transition  from  the  Annelida  to 
the  articulated  classes  properly  so  called.  They 
are  divided  by  entomologists  into  two  classes, 
the  lulida  or  Chilognatha,  and  the  Scolopen- 
dridte  or  Chilopoda,  a  division  strictly  in  con- 
formity with  their  internal  structure;  the  former 
in  fact  represent  the  Annelida;  like  the  Abran- 
chiate division  of  that  class,  they  breathe  by 
air-sacs,  communicating  with  spiracles  seen 
upon  the  exterior  of  their  bodies.  The  Scolo- 
pendra, on  the  contrary,  respire  by  tracheae, 
which  permeate  their  viscera,  as  in  the  insect 
classes.  In  the  generative  system  of  these 
creatures  a  similar  relationship  is  evident.  In 
lulus,  the  generative  system  occupies  the  ante- 
rior segments  of  the  body,  the  sexual  apertures 
being  found  upon  the  rings  near  the  cephalic 
extremity,  whilst  in  Scolopendra  they  are  placed, 
as  in  insects,  near  the  anal  orifice.  As  regards 
the  internal  sexual  organs  of  lulus,  but  little  is 
known  conclusively,  and  our  own  researches 
upon  this  point  have  not  been  sufficiently  satis- 
factory to  enable  us  to  speak  positively  con- 
cerning them,  although  the  result  leads  us  to 
suspect  that  in  these  creatures  not  only  are  the 
sexual  parts  analogous  to  those  of  the  Anne- 
lida, but  that,  as  in  many  of  that  class,  the  ova 
are  retained  in  cellular  interstices  surrounding 
the  intestinal  canal  for  some  time  prior  to  their 
expulsion. 

In  the  Scolopendra  the  generative  organs  are 
more  easily  distinguishable,  and  much  resem- 
ble those  of  insects  ;  they  are,  however,  exceed- 
ingly curious.  In  Jig.  201  we  have  represented 
the  male  apparatus  of  the  Scolopendra  mnrsi- 
tans.  The  testes  (a,  a,  a)  are  seven  in  number, 
and  closely  packed  in  parallel  lines;  each  testis 
is  composed  of  two  parts,  precisely  similar  to 
each  other,  which  are  seen  separate  at  b ;  from 
each  extremity  of  the  fusiform  testis  arises  a 
narrow  duct,  so  that  there  are  fourteen  pairs  of 
ducts  arising  from  the  fourteen  secreting  organs. 
Each  of  the  testicular  bodies  is  hollow  inter- 
nally. The  ducts  ultimately  end  in  a  common 
tube  (c),  which  soon  becomes  enlarged  and 
tortuous,  terminating  by  a  simple  aperture  near 
the  anus.  Just  prior  to  its  termination,  the  en- 
larged canal  receives  five  accessory  glands,  four 
of  which  (d,  d,  d,  d)  are  intimately  united,  until 
unravelled,  as  seen  in  the  figure,  while  the  fifth 
(e)  is  a  simple  ccecum  of  considerable  length. 

The  ovarian  system  of  the  female  Scolopen- 
dra is  a  single  tube,  apparently  without  secon- 
dary ramifications. 


Fig.  201. 


Male  generative  organs  of  the  Scolopendra  morsitam. 

Insects. — In  the  numerous  and  diversified 
tribes  of  the  insect  world  a  great  uniformity  is 
observable  in  the  general  arrangement  of  the 
generative  apparatus.  The  sexes  are  invariably 
separate,  but  while  the  internal  organs  are  con- 
stantly double  and  symmetrically  disposed  on 
both  sides  of  the  mesial  plane,  the  external 
parts  which  are  subservient  to  copulation  are 
removed  to  the  posterior  extremity  of  the  body, 
and  are  single.  Throughout  the  whole  class 
the  sexual  system  only  arrives  at  that  state  of 
perfection  which  is  compatible  with  reproduc- 
tion in  the  perfect  or  imago  state  of  the  animal, 
although  it  may  be  detected  in  a  rudimentary 
form  even  in  the  larva,  being  gradually  more 
and  more  perfected  during  the  developement 
of  the  pupa.  The  business  of  procreation  in 
insects  thus  exclusively  belonging  to  the  per- 
fectly formed  creature,  is  accomplished  only  at 
the  termination  of  their  existence,  and  the  whole 
tribe  is  remarkable  from  this  circumstance. 

The  internal  generative  organs  in  male  in- 
sects are  described  as  consisting  of  three  por- 
tions, the  testes  with  their  vasa  deferentia,  the 
vesicular  seminales,  and  the  canalis  excretorius. 
The  testes,  or,  in  other  words,  those  portions  of 
the  apparatus  which  are  supposed  to  furnish 
the  essential  part  of  the  fecundating-  fluid,  like 
the  rest  of  the  glandular  system,  consist  of  cceca 
or  utricles  floating  loosely  in  the  abdominal 


414 


ORGANS  OF  GENERATION. 


cavity,  immersed  in  the  juices  of  the  body, 
from  which  they  derive  their  secretion.  Never- 
theless, although  essentially  constructed  upon 
similar  principles,  the  testicular  cceca  present  a 
singular  diversity  of  form  in  different  genera, 
and  some  of  the  modifications  are  sufficiently 
curious,  although  in  the  present  state  of  our 
knowledge  it  would  be  hopeless  to  attempt  to 
explain  the  reason  of  their  existence.  Midler, 
from  a  comparison  of  the  researches  of  various 
authors  upon  this  subject,  has  given  the  follow- 
ing summary  of  the  principal  forms  of  the 
sperm-secreting  organs,  and  although  the  cata- 
logue of  varieties  might  doubtless  be  considera- 
bly extended,  those  given  will  abundantly  an- 
swer our  present  purpose.  Beginning  from  the 
tubular  vessel,  which  is  the  simplest  form  of 
the  testis,  he  traces  it  through  the  various  com- 
plications here  enumerated. 

1.  Simple  tubes  not  branched,  but  more  or 

less  convoluted  and  closed  at  one  extre- 
mity. 

2.  Spiral  tubes  similarly  closed,  as  in  Spho- 

drus  t  err  kola. 

3.  Spiral  tubes  rolled  up  into  little  balls,  as 

in  Carabus  auratus,  Aptiuus  displosor, 
Dytiscus,  &c. 

4.  Simple  tubes  irregularly  branched,  each 

branch  vesicular  near  its  extremity,  as 
in  Prionus  coriarius. 

5.  Simple  tubes,  divided  in  a  verticillate 

manner,  each  division  being  terminated 
by  a  capsule ;  Scurabteus  nasicornis, 
(Swammerdam.) 

6.  Simple  tubes,  divided  as  the  last,  but 

each  division  ending  in  a  vesicle,  as  in 
Trie hius fuse iatus. 

7.  Simple  tubes  ending  in  stellated  capsules, 

the  apices  of  which  are  produced  into 
slender  tubes ;  ISepa  cinerea,  (Swam- 
merdam.) 

8.  Simple  tubes  giving  off  a  series  of  canals, 

each  of  which  is  terminated  by  a  disc- 
shaped capsule ;  Cetonia  aurata. 

9.  Simple  tubes,  ending  in  flower-shaped 

capsules,  i.  e.  each  capsule  consisting 
of  a  central  vesicle,  with  other  smaller 
ones  placed  around  it,  as  in  Asida  gigas, 
CEdemera  adcarutu,  Diaperis  violacea, 
Tenebrio  obscurus,  (Edemera  carulea, 
&c. 

10.  Simple  tubes,  each  terminated  by  a  trans- 

verse capsule,  resembling  the  anther  of 
a  flower,  as  in  Apis,  Bombyx,  Scaris, 
Calvinia,  &c. 

11.  Simple  tubes,  dividing  into  minute  radia- 

ting utricles ;  Bostrichus  capucinus. 

12.  Simple  tubes,  each  terminated  by  a  cap- 

sule, which  is  covered  externally  with 
innumerable  little  vesicles  or  utricles,  as 
in  Musca  asilus,  Eiater  murinus,  Blaps 
gigas,  Telephones J'uscus. 

13.  Simple  tubes,  ending  in  an  elongated  sac- 

culus,to  the  sides  of  which  are  appended 
small  vesicles  arranged  in  longitudinal 
rows,  as  in  Semblis  bicauduta. 

14.  Simple  tubes  terminating  in  verticillate 

utricles,  as  in  Clerus  alveolarius. 

15.  Simple  tubes,  from  which  arise  utricles 


Fig.  202. 


arranged  like  the  teeth  of  a  comb,  as  in 

Hydrophilus  piceus. 

16.  Simple  tubes,  terminated  by  a  simple  sac- 

culus  ;  Gyrinus  nutator. 

17.  Simple  tubes,  terminated  by  a  bunch  of 

vesicles. 

18.  Simple  tubes,  dividing  into  minute  canals, 

forming  a  kind  of  cauda  equina  ;  Tri- 
chodes  apiarius. 

19.  Branched  tubes,  each  branch  being  termi- 

nated by  .  a  vesicle,  as  in  Stuphilinus 
maxitloHM.  (  Fig.  202.) 

20.  Tubes  very  much  branched,  some  of  the 

ramusculi  ending  in  bunches  of  leaf- 
like  utricles,  others  dilating  into  pe- 
dunculated vesicles ;  Sylpha  obscura. 
(  fig.  203.) 

21.  Simple  loculated  utricles,  as  in  Ephe- 

mera. 

It  is  manifest  from  this  sur- 
vey that,  although  the  secern- 
ing organs  differ  so  much  in 
form,  the  canals  composing 
them  invariably  terminate  in 
blind  extremities ;  nor  is  it 
less  obvious  that  the  nature 
of  the  testis  does  not  depend 
upon  any  peculiar  arrange- 
ment of  the  seminal  tubes,  but 
upon  the  increase  of  surface 
obtained  by  the  various  ar- 
rangement of  the  vessels.  Se- 
cretion, therefore,  here,  as  in 
every  other  case,  is  effected  by 
the  internal  surface  of  tubes, 
utricles,  sacculi,  &c.  the  same 
end  being  accomplished  in 
some  cases  by  means  of  very 
long  simple  canals,  which  in 
others  is  effected  by  smaller  Testicle  of  Staphy- 
branches,  tubes,  or  agglome-  linus  muxillosus. 
rated  vesicles. 

Fig.  203. 


V 


Testicle  of  Silpha  obscura. 


Appended  to  the  excretory  ducts  of  the  testi- 
cular organs,  near  their  termination,  is  found  a 
group  of  caecal  tubes,  evidently  destined  to 
provide  an  accessory  secretion;  these  have  been 
named  from  analogy  vesicula  seminules.  They 


ORGANS  OF  GENERATION. 


415 


vary  much  in  their  form,  being  sometimes  elon- 
gated, tortuous,  convoluted,  or  ventricose,  or  at 
others  short  and  straight.  The  seminal  vesicles  are 
generally  two  in  number,  even  in  those  Lepi- 
doptera in  which  the  testis  is  single.  In  some 
insects,  as  Tenebrio  molitor  and  Hydrophilus 
piceus,  there  are  four;  in  others,  as  Dytiscus 
marginalis,  six ;  and  in  Locusta  and  Blatta, 
they  are  very  numerous.  In  some  insects  these 
tubes  are  found  to  be  of  surprising  length ; 
thus  in  Oryctes  nasicornis  they  are  twenty 
times  as  long  as  the  body, and  in  Cetonia  aurata 
even  sixty  times  the  length  of  the  animal.  The 
vasa  deferentia  and  vesiculse  seminales  ulti- 
mately terminate  in  one  common  tube,  the  ca- 
nalis  excretorius,  which  communicates  with  the 
root  of  the  penis;  this  canal  is  composed  of 
muscular  walls  largely  supplied  with  tracheal 
vessels,  serving  as  a  receptacle  for  the  genital 
secretions,  and  no  doubt  is  the  agent  by  which, 
during  coition,  their  expulsion  is  effected.  The 
penis  of  insects  is  a  hollow  tube,  capable  of 
being  protruded  from  the  anal  extremity  of  the 
body  :  its  texture  is  generally  membranous, 
but  sometimes  horny,  and  its  shape  exhibits 
considerable  variety  ;  it  is  usually  cylindrical 
or  nearly  so,  becoming  more  slender  towards 
its  termination.  In  Cliermis  pyrus,  however, 
the  end  is  enlarged ;  in  the  common  wasp 
it  is  spoon-shaped;  in  Cruhro  bilobed,  and  in 
some  Vespa  curved  and  bifid  at  its  extremity. 
In  Musca  vivipura  its  apex  is  covered  with 
spines ;  in  Tyrop/iaga  putris  and  some  other 
Muscidaa  it  is  spiral.  The  penis  of  Coleoptera 
is  furnished  with  a  bivalve  sheath,  destined  to 
open  the  vulva  of  the  female  prior  to  its  inser- 
tion. In  some  Diptera  (Muscidae)  a  remark- 
able inversion  of  the  usual  arrangement  of  the 
organs  of  copulation  is  observable  ;  in  these  the 
females  are  provided  with  a  retractile  penis, 
whilst  in  the  males  the  generative  apparatus 
terminates  by  a  simple  aperture.  During  coi- 
tion in  this  case,  it  is  the  penis  of  the  female 
which  is  introduced  into  the  genital  opening  of 
the  male,  and  thus  becomes  the  recipient  of  the 
fecundating  fluid.  The  Dragon-flies  (Libel- 
lula)  are  remarkable  from  the  position  which 
the  male  organ  is  found  to  occupy,  being  placed 
under  the  anterior  part  of  the  elongated  abdo- 
men, but  in  the  female  the  sexual  aperture 
occupies  the  usual  situation  near  the  anus. 
This  arrangement  accounts  for  the  singular 
position  which  these  insects  assume  during 
copulation. 

In  addition  to  the  organs  above  enumerated 
as  composing  the  male  system  in  insects,  we 
may  notice  appendages  which  are  found  in 
some  tribes  which  materially  assist  in  effecting 
the  intercourse  of  the  sexes  :  these  are  named 
prekensores,  and  serve  to  seize  and  secure  the 
female  during  coitus.  These  holders  assume  a 
great  variety  of  shapes,  and  likewise  are  diffe- 
rently disposed  according  to  circumstances. 
They  generally  surround  the  aperture  through 
which  the  penis  is  extruded,  but  in  Libellula 
the  mode  in  which  the  sexes  embrace  each 
other  renders  additional  security  indispensable; 
in  this  tribe,  therefore,  besides  the  anal  preken- 
sores, an  additional  pair  of  forceps  is  placed 


under  the  second  abdominal  segment.  The 
prehensores  are  generally  two  in  number;  but 
in  many  Lepidoptera,  Conopis  and  Libellula, 
three  are  placed  around  the  anus.  In  Culex 
there  are  two  pairs.  In  Locusta  morbillostz 
there  are  five,  and  in  Formica  six  holders.  In 
some  tribes,  as  Megachilis,  Agrionidas,  and 
Locusta,  they  are  retracted  within  the  abdomen 
when  not  employed. 

In  insects  the  ovigerous  or  female  generative 
apparatus  consists  likewise  essentially  of  tubes 
or  cceca,  the  arrangement  of  which  is  tolerably 
uniform.  They  may  be  divided  into  the  ovaria, 
the  oviducts,  the  spermotheca,  or  receptacle 
for  the  seminal  fluid  of  the  male,  the  accessory 
glands,  and  the  ovipositor,  which  latter  is,  in 
many  insects,  an  instrument  adapted  to  intro- 
duce the  eggs  at  the  period  of  their  extrusion 
into  situations  suited  to  their  developement. 

The  ovaria  are  double  throughout  the  whole 
class,  each  being  composed  of  a  variable  num- 
ber of  membranous  tubes  arising  from  the 
oviduct.  Rifferschweils  considers  the  ovaries 
to  be  formed  upon  two  primary  types,  being 
either flagelliform,  that  is,  composed  of  conical 
tubes  of  equal  length,  which  are  inserted  at  the 
same  place  at  the  extremity  of  the  oviduct,  as 
in  the  Lepidoptera,  the  Bee,  &c. ;  or  racemose, 
consisting  of  short  conical  tubes,  so  proceeding 
from  the  primary  branches  as  to  render  the 
ovary  racemose  or  pinnated,  such  as  they  are 
in  many  Neuroptera,  Coleoptera,  and  Diptera. 

The  number  of  tubes  composing  each  ovary 
varies  in  different  genera  and  species ;  some- 
times there  are  but  two,  at  others  four,  five, 
six,  eight,  or  twelve,  and  in  the  more  prolific 
insects  this  number  is  much  increased;  thus,  in 
Acrida  viridisvima  there  are  thirty,  and  in  the 
hive-bee  not  fewer  than  a  hundred  and  fifty 
cceca  in  each  ovarian  packet.    The  number  of 
eggs  will  of  course  depend  upon  the  number 
and  divisions  of  these  ovarian  tubes,  and  thus 
while  some  insects  only  lay  two,  four,  or  six 
eggs,  others  will  produce  sixty  or  seventy,  and 
some  gregarious  insects  a  much  greater  num- 
ber :  thus  the  hive-bee  will  probably  give  birth 
to  many  thousand  young,  and  in  the  Termite 
ant  (Hermes  bellicosus)  the  fecundity  of  the 
female  is  absolutely  incalculable.    This  extra- 
ordinary fertility  renders  indispensable  certain 
restrictions  which  we  find  imposed  upon  this 
numerous  class,  tending  materially  to  limit 
their  excessive  multiplication.    Thus,  through- 
out the  whole  race  one  generation  only  is  pro- 
duced from  the  same  insect,  the  business  of 
reproduction  being  usually  the  termination  of 
its  existence ;  and  in  the  most  prolific  tribes, 
namely,  those  which  live  in  society,  as  the  Bee 
and  the  Termite,  one  female  only  in  each  com- 
munity is  found  to  be  fertile,  the  sexual  organs 
of  all  the  rest  remaining  in  a  rudimentary  or 
undeveloped  state,  although  capable  of  de- 
velopement, should   the  destruction    of  the 
queen  render  such  a  provision  for  the  preserva- 
tion of  the  race  indispensably  necessary.  (See 
Inseota.) 

The  oviductus  or  excretory  canal  common 
to  the  ovarian  tubes  of  the  corresponding  side 
of  the  body,  sometimes  opens  into  the  cloaca, 


416 


ORGANS  OF  GENERATION. 


the  eggs  escaping  by  the  anal  passage;  but  in 
other  cases,  having  joined  that  of  the  opposite 
side,  it  terminates  externally  by  a  distinct 
aperture  ;  near  its  extremity,  however,  it  re- 
ceives the  auxiliary  tubes  or  ccoca,  namely, 
the  spermotlieca  and  the  accessory  glands. 

The  spei  motheca  is  a  membranous  saecu- 
lus  of  varying  size  and  shape,  regarded  by 
Herold  and  Malpighi  as  a  receptacle  in 
which  the  seminal  fluid  of  the  male  is  de- 
posited and  retained, — an  opinion  which  has 
been  sanctioned  by  subsequent  anatomists ;  it 
is  found  only  in  such  insects  as  deposit  their 
eggs  in  slow  succession,  and  is  presumed  to 
be  a  provision  for  the  gradual  fertilization  of 
the  ova  during  their  transit  through  the  ovi- 
duct. It  is  only  upon  this  supposition  that  it 
is  possible  to  account  for  the  impregnation  of 
some  insects  which  are  employed  for  a  long 
period  in  the  business  of  oviposition,  as  is  the 
case,  for  instance,  with  the  hive-bee,  in  which  a 
single  coitus  fertilizes  all  the  eggs  that  are  laid 
for  a  space  of  two  years,  amounting  some- 
times to  twenty  or  thirty  thousand  in  number; 
and  yet,  in  this  case,  it  is  difficult  to  conceive 
how  so  small  a  reservoir,  scarcely  larger  in- 
deed than  the  head  of  a  pin,  can  retain  a 
sufficiency  of  this  fluid  for  such  a  purpose,  a 
difficulty  which  is  scarcely  lessened  by  admit- 
ting the  hypothesis  of  Dr.  Iiaighton,  who  refers 
the  act  of  impregnation  rather  to  some  pene- 
trating effluvium  or  uuru  sem'maiis,  which  the 
seminal  liquor  may  emit  during  a  long  period, 
than  to  actual  contact  between  the  semen  and 
the  ova. 

The  auxiliary  glands  (glandule  succenlu- 
riata ),  which  are  appended  to  the  oviduct  of 
insects,  perform  an  office  which  is  by  no  means 
satisfactorily  determined;  the  most  usual  sup- 
position is  that  they  furnish  some  secretion 
connected  with  the  investment  of  the  ova, 
either  for  the  completion  of  the  shell,  or,  as  is 
more  probably  the  case,  for  the  purpose  of 
uniting  them  together  by  a  tenacious  mucus 
into  the  long  strings  or  masses  in  which  they 
are  not  unfrequently  extruded.  The  structure 
of  these  secerning  caeca  differs  in  different 
insects,  but  will  be  found  to  conform  in  most 
cases  to  one  or  other  of  the  following  types: — ■ 

1.  Most  frequently  they  are  merely  elon- 
gated tubes  closed  at  one  extremity  while  the 
other  opens  into  the  oviduct. 

2.  In  some  cases  the  primary  ccaca  give  off 
secondary  branches. 

3.  In  others,  as  in  Hippobosca,  they  are 
ramified  tubes  terminated  by  blind  canals. 

4.  In  Etater  Murium  they  present  a  very 
remarkable  structure,  being  composed  of  a 
number  of  triangular  capsules  united  by  canals 
arising  from  each  angle  until  the  terminal  vessels 
are  reduced  to  simple  cosca. 

The  ovipositor  is  the  last  part  of  the  female 
generative  apparatus  of  insects  which  we  have 
to  notice.  This  singular  appendage  to  the 
oviduct  presents  many  varieties  in  its  structure, 
being  adapted  to  the  introduction  of  the  ova  into 
certain  localities  either  fitted  for  their  matu- 
ration, or,  as  is  more  frequently  the  case, 
suited  to  the  necessities  of  the  larva  after  its 


escape  from  the  egg ;  but  a  detailed  account 
of  the  forms  which  this  organ  assumes  in  dif- 
ferent tribes  would  necessarily  be  incompatible 
with  the  limits  of  this  article,  and  the  reader  is 
therefore  referred  for  further  information  to  the 
article  Insecta. 

Some  insects  are  ovo-viviparous  in  a  mo- 
dified sense,  and  their  offspring  are  produced 
in  the  larva  or  even  in  the  pupa  state,  the  eggs 
being  hatched  in  the  body  of  the  parent,  and 
the  young  matured  to  a  certain  extent  before 
they  are  expelled.  In  such  cases  the  oviducts 
unite  to  form  a  capacious  matrix,  in  which  at 
certain  seasons  the  larvaa  are  contained  either 
agglomerated  in  masses,  or  arranged  parallel 
with  each  other  in  flat  bands.  In  this  state 
each  larva  is  invested  in  a  delicate  membra- 
nous bag.  It  is  remarkable  that  all  these  larvee 
are  carnivorous,  their  office  being  to  remove 
putrifying  flesh ;  hence  the  necessity  of  their 
being  produced  in  such  a  state  as  immediately 
to  commence  the  woik  to  which  they  are  des- 
tined. 

Some  Aphides,  or  plant-lice,  are  ovo-vivi- 
parous in  the  early  part  of  the  year,  but  ovi- 
parous as  winter  approaches, — a  provision  evi- 
dently intended  to  secure  the  preservation  of 
the  embryo  during  the  inclement  season,  the 
eggs  remaining  unhatched  until  the  return  of 
spring. 

The  Aphides  likewise  in  their  mode  of  gene- 
ration furnish  the  physiologist  with  one  of  the 
most  extraordinary  anomalies  met  with  in  the 
animal  kingdom.  From  an  accurate  series  of 
observations,  first  instituted  by  Bonnet,  and 
subsequently  confirmed  by  the  indefatigable 
Lyonnet,  it  is  now  received  as  an  established 
fact  that  the  females  of  these  insects  have  the 
faculty  of  giving  birth  to  young  ones  without 
having  had  any  intercourse  with  the  other  sex. 
From  the  experiments  of  these  naturalists  it 
appears  to  have  been  incontestably  proved  that 
if  a  female  Aphis  at  the  moment  of  its  birth 
be  rigorously  kept  from  communication  with 
others  of  its  species,  it  will,  if  supplied  with 
proper  food,  give  birth  to  a  brood  of  young 
ones,  and  not  only  so,  but  if  one  of  the  off- 
spring so  produced  be  similarly  treated,  it  like- 
wise will  prove  fruitful,  and  so  on  to  the  fifth 
generation,  according  to  Bonnet,  or  even  still 
further,  as  Lyonnet  afterwards  ascertained. 
Bonnet  supposed,  in  explanation  of  this  cir- 
cumstance, that  the  Aphides  are  truly  andro- 
gynous, each  being  possessed  both  of  ovige- 
rous  and  impregnating  organs  ;  yet  this  sup- 
position is  incompatible  with  the  fact,  that  the 
male  insect  is  almost  as  common  as  the  female, 
and  that  the  sexes  copulate  in  the  usual  manner 
during  the  termination  of  the  summer  season. 
The  only  solution  of  this  phenomenon  appears 
to  be  that  one  intercourse  with  the  male  suf- 
fices for  the  impregnation  of  all  the  females 
which  in  one  season  spring  from  the  same 
union.  But  the  Aphides  are  not  the  only  ex- 
amples of  this  curious  fact,  as  some  of  the 
Branchiopod  Crustaceans,  as  Daphnia  pennuta, 
Mull.  ( Monoculus  pulex,  L.)  are  equally  ca- 
pable of  producing  fertile  females  through 
several  successive  generations ;  nevertheless 


ORGANS  OF  GENERATION. 


417 


both  Bonnet  and  Jurine  observed  that  the  fe- 
male Aphides  and  Branchiopods  that  were 
fertile  without  the  usual  intercourse  of  the 
sexes  were  less  fruitful  than  their  mother,  and 
those  of  the  last  generation  less  so  than  the 
first. 

Arachnida. —  In  the  Arachnida  the  gene- 
rative system,  both  in  the  male  and  female, 
is  even  more  simple  than  that  of  insects.  The 
testes  of  the  male  are  two  in  number,  each 
being  an  elongated  membranous  bag,  closed  at 
one  extremity,  whilst  the  opposite  is  conti- 
nuous with  a  slender  and  tortuous  vas  deferens, 
the  terminations  of  which  are  indicated  ex- 
ternally by  two  very  small  orifices  distinguish- 
able on  the  under  surface  of  the  abdomen  near 
its  junction  with  the  thorax.  The  apertures 
through  which  the  seminal  fluid  is  discharged 
are  totally  unprovided  with  any  apparatus  of 
intromission  or  excitement;  in  lieu  of  which 
many  genera  are  provided  with  a  singular  sub- 
stitute, or  at  least  with  an  organ  supposed  by 
some  authors  to  be  an  exciting  organ.  This  is 
found  at  the  extremity  of  the  maxillary  palpus, 
but  for  a  detailed  account  of  its  structure  and 
presumed  functions  the  reader  is  referred  to  the 
article  Arachnida. 

The  female  organs  of  the  Araneidae  are 
equally  devoid  of  complication.  The  ovaries 
are  simple  membranous  bags,  which  occupy 
when  distended  a  considerable  portion  of  the 
abdomen,  and  are  found  to  contain  ova  ag- 
gregated together  in  considerable  numbers. 
From  each  of  these  ovigerous  sacs  a  short 
canal  leads  to  an  aperture  situated  near  the 
base  of  the  abdomen,  through  which,  when 
mature,  the  ova  are  discharged.  The  most  re- 
markable circumstance  observable  in  this  form 
of  the  generative  system  is  the  complete  sepa- 
ration which  exists  between  the  sexual  organs 
of  the  two  sides  of  the  body,  which,  both  in 
the  male  and  female,  not  only  do  not  com- 
municate internally,  but  open  upon  the  exterior 
by  distinct  apertures  ;  the  insulation  is,  in  fact, 
so  perfect  that  in  some  cases  the  eggs  gene- 
rated in  the  two  ovaria  are  laid  at  distinct  and 
distant  periods.  According;  to  Audebert  some 
spiders  are  rendered  fertile  for  several  years  by 
one  intercourse  with  the  male. 

In  the  Scorpions  the  male  generative  ap- 
paratus consists  of  a  testis  composed  of  nu- 
merous tubes  united  together,  so  as  to  form  a 
series  of  loops,  the  secretion  of  which  is  dis- 
charged externally  by  a  double  penis  resembling 
that  of  some  reptiles,  which  is  protruded 
through  a  valvular  aperture  seen  upon  the 
ventral  surface  of  the  thorax. 

The  female  organs  of  the  Scorpion,  like 
those  of  the  male,  are  composed  of  loops  of 
tubes,  uniting  together  at  different  points,  and 
when  distended  with  ova  resembling  a  neck- 
lace of  beads  :  they  open  by  two  canals,  (vol.  i. 
fig.  84,  c,  p.  205),  at  the  same  point  which  the 
sexual  aperture  of  the  male  has  been  seen  to  oc- 
cupy, each  having  a  small  caecum  or  succentu- 
riate  gland  appended  near  its  termination.  The 
eggs  of  Scorpions  are  hatched  in  the  oviducts, 
and  the  progress  of  the  develop>ement  of  the 
embryo  maybe  easily  distinguished  through  the 


transparent  coats  of  the  ovum,  resembling  most 
accurately  that  observed  by  Herold  in  the  evo- 
lution of  the  young  spiders,  figures  of  which 
are  given  elsewhere.* 

Crustacea. — As  in  the  Arachnida,  the  gene- 
rative system  of  Crustaceans  is  for  the  most 
part  double,  the  parts  belonging  to  the  two 
sides  of  the  body  being  generally  completely 
distinct  from  each  other,  not  only  internally 
but  at  their  termination.  In  the  higher  orders 
the  testes  of  the  male  and  the  ovaries  of  the 
other  sex  are  found  to  be  situated  in  the  dorsal 
region  of  the  thorax  ;  in  both  cases  these 
organs  appear  at  first  sight  to  be  of  a  dense 
glandular  structure,  but,  on  examination,  are 
found  to  be  essentially  composed  of  tubular 
convolutions.  In  both  the  male  and  the  fe- 
male, the  excretory  canals  are  simple  tubes, 
which,  after  some  convolutions,  terminate  in  the 
male  by  prominent  apertures,  found  upon  the 
eoxal  portion  of  the  fifth  or  posterior  pair  of 
true  legs,  and  in  the  female  by  similar  open- 
ings at  the  base  of  the  third  pair. 

As  in  Insects,  the  female  organs  have  in 
many  genera  a  sacculated  appendage,  or  copu- 
latory  pouch  as  it  is  termed,  which  is,  in  fact, 
analogous  in  function  to  the  spermotheca  of 
insects,  serving  as  a  reservoir  in  which  the 
male  semen  is  detained  for  the  purpose  of  im- 
pregnating the  eggs  as  they  successively  escape 
from  the  body.  After  their  exclusion  from  the 
oviduct  the  eggs  of  Crustaceans  are  generally 
carried  about  by  the  female.  In  the  Decapoda 
they  are  appended  by  a  glutinous  material  to 
the  false  feet  situated  under  the  tail.  In  the 
Isopoda  and  others  they  are  retained  in  recep- 
tacles formed  by  scales  placed  under  the  ab- 
domen, whilst  in  the  Entomostracous  forms, 
as  well  as  in  many  Epizoa  approximating  the 
Crustacea  in  structure,  a  remarkable  provision 
is  made  for  perfecting  the  eggs  external  to  the 
bodies  of  these  minute  creatures,  the  females 
being  provided  with  one  or  two  membranous 
sacs  appended  to  the  posterior  part  of  the 
abdomen,  into  which  the  oviducts  open,  and  in 
which  the  ova  are  retained  until  they  arrive  at 
maturity. 

Mollusca. —  Several  of  the  more  perfectly 
organised  Mollusca  come  likewise  under  this 
division  of  our  subject.  Such  are  the  Pectini- 
branchiate  Gasteropoda,  in  which  the  structure 
of  the  generative  apparatus  is  sufficiently  sim- 
ple. In  the  male  a  large  testis,  composed  of 
racemose  follicles,  shares  with  the  liver  the 
convolutions  of  the  shell :  from  this  the  seminal 
secretion  passes  by  a  long  and  tortuous  vas 
deferens  to  the  extremity  of  the  penis,  which 
is  in  these  creatures  an  extensile  and  very 
muscular  organ,  situated  on  the  right  side  of 
the  neck,  and  not  unfrequently  of  enormous 
size  when  compared  with  the  bulk  of  the 
animal. 

The  ovarium  in  the  female  Pectinibranchiate 
Gasteropods  corresponds  in  position  with  the 
male  testis ;  the  oviduct  arising  from  it  is 
capacious,  glandular,  and  convoluted,  serving 
in  some  genera,  as  in  Turbo,  as  a  receptacle 

*  Vide  Article  ARACHNIDA. 


418 


ORGANS  OF  GENERATION. 


in  which  the  eggs  are  frequently  hatched. 
Near  its  termination  the  oviduct  communicates 
with  a  glandular  apparatus  supposed  to  furnish 
the  viscid  envelope  by  means  of  which  the 
eggs  are  generally  agglutinated  together. 

In  the  Cephalopoda  likewise,  as  in  the  Mol- 
lusca  generally,  the  generative  system  is  single. 
In  this  class  the  testis  is  an  azygos  viscus, 
composed  of  elongated  branched  cceca,  in- 
closed in  a  membranous  capsule,  into  which 
apparently  the  seminal  fluid  escapes.  The  vas 
deferens  is  narrow,  and  convoluted  at  first, 
but  afterwards  it  enlarges  and  becomes  mus- 
cular in  its  structure,  serving  doubtless  as  an 
instrument  for  the  expulsion  of  the  semen. 
This  seminal  canal  receives  the  duct  of  a  large 
glandular  mass,  and  dilating  into  a  pouch, 
ultimately  terminates  at  the  root  of  a  rudi- 
mentary penis,  apparently  adapted  to  intro- 
mission, although  it  has  not  yet  been  ascer- 
tained whether  actual  copulation  takes  place, 
or  whether  the  ova  are  fecundated  after  their 
extrusion,  as  is  the  case  with  fishes. 

In  the  female  Cephalopoda  the  ovarium,  like 
the  testis  of  the  male,  is  azygos,  and  placed 
in  the  same  situation.  Its  structure  is  remark- 
able, being  a  strong  capsule,  to  the  interior  of 
which  adheres  a.  cluster  of  vesicular  bodies 
denominated  ovisacs,  from  which,  at  certain 
seasons,  the  ova  escape.  From  the  ovarian 
capsule  arises  the  oviduct;  this  is  in  some 
instances  a  single  tube,  but  in  others  divides 
into  two  canals;  in  either  case,  before  its  ter- 
mination behind  the  base  of  the  syphon,  it 
passes  through  a  thick  laminated  glandular 
structure,  which  secretes  the  dense  coriaceous 
investment  enclosing  the  ova,  and  the  material 
which  unites  them  into  the  racemose  clusters  in 
which  they  are  usually  found. 

Verlebrata  Ovipara. — In  the  vertebrate  divi- 
sion of  the  animal  kingdom  the  generative 
system  presents  great  varieties,  although  from 
the  lower  to  the  higher  orders  we  may  distinctly 
trace  a  series  of  gradations  which,  in  a  physio- 
logical point  of  view,  are  of  the  highest  interest. 

In  Fishes  the  ovaria  are  formed  upon  two 
distinct  types.  In  the  osseous  fishes  they  are 
for  the  most  part  two  large  membranous  sacs, 
which,  when  distended,  occupy  a  considerable 
share  of  the  abdominal  cavity;  these  open  by  a 
short  canal  in  the  vicinity  of  the  anus.  In  these 
capacious  sacs  the  ova  are  developed  :  they  are 
found  united,  together  by  a  delicate  membrane, 
and  attached  in  numerous  festoons  to  the  walls 
of  the  ovary  until  sufficiently  mature  for  expul- 
sion, when,  breaking  loose  from  their  con- 
nexions, they  escape  into  the  ovarian  cavity 
and  are  discharged  through  its  excretory  duct. 
In  this  case  the  Fallopian  tubes  found  in  other 
vertebrata  do  not  exist,  the  oviduct  being  pro- 
longed from  the  ovary  itself  in  the  same  manner 
as  the  duct  of  a  secreting  gland,  and  the  whole 
apparatus,  in  fact,  strongly  resembles  what  we 
have  found  in  the  Conchifera  and  other  Mol- 
lusks,  the  great  distinction  consisting  in  the 
necessity  which  here  exists  for  the  impregnation 
of  the  ova  by  the  agency  of  the  male.  The 
fecundation  of  the  eggs  is  effected  externally, 
after  their  expulsion,  and,  in  fact,  it  is  the 


spawn  rather  than  the  female,  which  forms  the 
object  of  the  pursuit  of  the  male,  as  in  most 
instances  both  sexes  appear  as  careless  con- 
cerning each  other  as  they  are  of  the  off- 
spring which  they  produce.  The  ova,  which 
are  incalculably  numerous,  are  deposited  in 
shallow  water,  where  they  may  receive  the 
influence  of  the  solar  beams,  and  in  this  situa- 
tion are  eagerly  sought  after  by  the  males 
destined  to  make  them  fertile;  these,  urged 
apparently  by  the  necessity  of  ridding  them- 
selves of  an  inconvenient  load,  discharge  the 
secretion  of  their  voluminous  testes  into  the 
water,  which,  becoming  diffused  in  the  vicinity 
of  the  ova,  is  sufficient  for  their  impregnation. 
In  the  males  of  this  class  of  fishes  the  testes 
are  of  enormous  size,  equalling  in  bulk  the 
ovaria  of  the  other  sex,  and  occupying  a  corres- 
ponding situation  in  the  abdomen.  Each  testis 
is  made  up  of  a  congeries  of  seminal  canals, 
which,  when  inflated  through  the  excretory 
duct,  distend  the  whole  organ.  The  seminal 
tubes  are  in  most  instances  arranged  parallel  to 
each  other,  and  are  closed  at  one  extremity 
while  the  other  terminates  in  the  common  canal 
or  vas  deferens,  which  in  every  respect  resem- 
bles the  oviduct  of  the  female. 

This  is  the  most  usual  structure  of  the  male 
apparatus  of  fishes,  but  in  some,  as  in  the  Shad 
( C/upea  Alosa),  the  seminiferous  tubes  form 
innumerable  ramifications  and  anastomoses  in 
the  substance  of  the  testicle,  easily  discernible 
by  the  naked  eye;  and  from  the  plexus  thus 
produced  ccecal  tubes  are  prolonged  to  the  sur- 
face of  the  organ,  where  they  terminate  by 
rounded  extremities,  giving  the  whole  viscus, 
externally,  a  granulated  appearance.  (Fig. 
204.) 

A  few  of  the  osseous  fishes  form  remarkable 
exceptions  to  the  usual  mode  of  impregnation, 
the  ova  of  the  female  being  in  such  fecundated 
prior  to  their  expulsion  by  actual  copulation 
with  the  male ;  and  in  some  rare  instances,  as 
in  the  Blennins  viviparus,  the  young  are  even 
produced  alive,  the  ova  being  retained  within 
the  oviduct  until  they  are  hatched.  In  such 
cases  the  termination  of  the  vas  deferens  swells 
into  an  external  projection  resembling  a  rudi- 
mentary penis,  and,  indeed,  actually  performing 
the  office  of  an  organ  of  intromission. 

In  the  more  highly  organized  cartilaginous 
fishes,  and  even  in  some  osseous  genera,  the 
structure  of  the  generative  system  is  entirely 
different,  commencing  that  type  which  charac- 
terizes the  reproductive  organs  of  all  the  other 
vertebrate  classes.  In  these  the  ovaria  are  not 
hollow  sacs  which  have  their  cavity  prolonged 
to  the  exterior  of  the  body,  but  the  ova  are 
developed  between  layers  of  membrane  sus- 
pended in  the  abdomen,  which  are  unprovided 
with  any  canal  immediately  communicating 
with  them.  Such  are  the  ovaria  of  the  Eel 
and  the  Lamprey,  which  are  formed  of  nume- 
rous festoons  of  delicate  and  vascular  membrane 
suspended  in  front  of  the  spine.  The  ova  pro- 
duced between  these  membranous  layers  when 
mature  break  loose  into  the  cavity  of  the 
abdomen,  and  are  discharged  through  a  simple 
orifice  in  the  neighbourhood  of  the  anus.  In 


ORGANS  OF  GENERATION. 


419 


Fig.  204. 


Structure  of  the  Testes  in  Clupea  Alosa. 


this  arrangement  we  have,  therefore,  the  simplest 
form  of  the  isolated  ovaria  of  Reptiles,  Birds, 
ond  Mammalia,  in  alt  of  which  the  ova  escape 
Jrom  the  surface  of  the  ovary,  not  from  its 
interior;  and  in  the  orifice  through  which  the 
eggs  are  ultimately  expelled  from  the  abdomen 
we  see  the  first  rudiment  of  a  Fallopian  tube. 
In  the  Lamprey  this  orifice  is  prolonged  into 
a  short  canal,  and  in  Rays  and  Sharks  assumes 
the  form  of  an  oviduct  with  which  we  shall 
afterwards  see  the  Fallopian  tubes  of  Mammals 
are  identical;  for  whatever  the  complication 
which  it  afterwards  assumes,  the  oviduct  or 
Fallopian  tube  (for  the  two  are  the  same  in 
function)  only  receives  the  ova  after  their  escape 
into  the  cavity  of  the  abdomen  to  facilitate 
their  ultimate  expulsion.    In  Rays  and  Sharks 
the  oviduct  is  double,  commencing,  however, 
by  a  fimbriated  aperture  common  to  both, 
which  receives  the  eggs  from  the  ovaria ;  each 
oviduct  is  at  first  narrow  and  membranous, 
having  its   lining  membrane  longitudinally 
plicated,  but  before  its  termination  the  walls 
suddenly  increase  in  thickness,  developing  in 
their  interior  a  large  gland  destined  to  furnish 
the  horny  covering  which  invests  the  eggs  of 
these  creatures.  Beyond  the  gland  the  oviduct 
expands  into  a  capacious  bag,  which  communi- 
cates with  the  cloaca. 

In  this  class  of  fishes  the  testis,  like  the 
ovary,  is  not  hollow.  In  the  Eel  and  Lamprey 
the  secretion  of  the  testis  escapes  from  the 
external  surface  of  the  organ  into  the  abdomi- 
nal cavity,  whence,  like  the  eggs  in  the  females 
of  the  same  tribes,  it  is  expelled  through  a 
simple  orifice  provided  for  its  egress.  In  these 
creatures  the  testis  and  ovarium  are  so  entirely 
similar  that  they  have  been  confounded  by 
authors,  the  secreting  granules  in  the  one  sex 
and  the  ova  in  the  other  being  both  disposed 


in  regular  laminae,  and  only  differing  inas- 
much as  the  testicular  granules  are  smaller 
than  the  mature  ova. 

The  structure  of  the  testis  in  Rays  and 
Sharks  is  peculiar,  these  animals  being  appa- 
rently provided  with  both  the  kinds  of  testis 
above  described.    Each  testicle  consists  of  two 
portions  quite  detached  from  each  other;  the 
one  is  formed  of  an  aggregation  of  globular 
masses  as  large  as  peas,  from  which  no  excre- 
tory duct  has  been  found  to  issue ;  the  other  is 
made  up  of  convoluted  canals,  which,  gradually 
uniting  together,  terminate  in  a  capacious  tube. 
The  tuberculated  mass  has  been  described  as 
the  testis,  while  the  convoluted  tubes  of  the 
other  portion  were  regarded  as  an  epididymus, 
whence  the  vas  deferens  took  its  origin.  There 
is,  however,  no  communication  between  the 
granular  part  and  that  whence  the  vas  deferens 
issues ;  it  is,  therefore,  probable  that  the  former 
is  analogous  to  the  solid  testis  of  the  Eel  and 
Lamprey,  pouring  its  secretion  into  the  abdo- 
minal cavity,  whence  it  is  emitted  through  the 
apertures  well  known  to  communicate  in  these 
creatures  between  the  peritoneal  bag  and  the 
exterior,  while  the  latter  is  identical  with  the 
usual  form  of  the  testis  in  osseous  fishes. 

TheBatrachian  Reptiles  in  their  mode  of  gene- 
ration, as  well  in  so  many  other  points  of  their 
economy,  form  the  transition  from  the  branchi- 
ferous  to  the  pulmonary  forms  of  theVertebrata, 
and  hence  the  study  of  their  sexual  organs  is  ex- 
ceedingly interesting.   The  ovaria  of  these  ani- 
mals in  their  entire  organization  resemble  those 
of  the  Lamprey.  Their  size,  however,  is  much  in- 
ferior, and  t'*e  whole  or^an  exhibits  a  more  con- 
centrated arrangement.  The  vascular  membrane 
which  forms  each  ovary  is  arranged  in  large 
folds  on  the  sides  of  the  spine,  and  the  ova 
are  deposited  in  great  numbers  between  the 
lamellae  of  which  it  consists.    The  oviducts 
are  long  and  tortuous,  each  commencing  by  a 
fimbriated  aperture  which  is  found  to  be  situated 
at  the  side  of  the  pericardium,  and  so  bound 
down  in  that  position  by  its  peritoneal  attach- 
ment-; thatwhen  the  interval  which  separates  this 
point  from  the  ovaria  is  considered,  it  is  difficult 
to  conceive  how  the  ova,  when  dislodged  from 
the  nidus  in  which  they  were  formed,  can  be 
brought  into  the  oviduct;  the  only  supposition, 
in  fact,  which  will  account  for  it  is,  that  the 
eggs  break  loose  into  the  abdominal  cavity  and 
thus  make  their  way  to  the  extremities  of  the 
oviducts.     Before  terminating  in  the  cloaca 
the  oviducts  expand  into  capacious  recepta- 
cles, in  which  the  ova  are  collected  prior  to 
their  expulsion,  and  glued  together  by  a  glairy 
secretion  into  masses  which  distend  the  whole 
of  the  abdomen. 

The  ovaria  of  the  Salamanders  resemble 
those  of  the  frog,  as  do  the  oviducts,  but  the 
membranous  sacs  which  retain  the  ova  are  less 
considerable  than  in  the  Anourous  Batrachia  : 
the  same  observations  apply  to  the  perenni- 
branchiate  orders. 

The  structure  of  the  testis  in  frogs  is  almost 
the  same  as  that  of  the  same  organ  in  the 
cuttle-fish.  If  the  investing  tunic  be  removed, 
the  whole  substance  of  the  organ  appears  com- 
posed of  globules;  but  if  these  are  gently  sepa- 


420 


ORGANS  OF  GENERATION. 


rated,  they  are  found  to  be  merely  the  blind 
terminations  of  as  many  seminal  tubes  which 
run  from  the  centre  to  the  circumference  of  the 
testicle.    The  seminiferous  ducts  arising  from 


Testis  of  Frog. 

these  perforate  the  investing  tunic  of  the  kidney, 
upon  which  the  testis  is  placed,  and,  according 
to  Swammerdam,  terminate  in  the  ureters, 
which  thus  perform  likewise  the  office  of  the 
vas  deferens. 

We  have  carefully  repeated  Swammerdam 's 
dissection  of  these  parts,  which  are  represented 
at  fig.  206. 

Fig.  206. 


Generative  organs  of  Male  Frog. 

a,  Cloaca  ;  b,  opening  of  genito-urinary  canal ; 
c,  opening  of  bladder  into  cloaca ;  d,  rectum; 
e,  bladder  ;  /,  testes,  that  of  the  right  side  in 
situ;  g,  kidneys;  h,  seminiferous  tubes;  i, 
tube  serving  both  as  ureter  and  vas  deferens  ; 
k,  vesiculae  seminales  ;  I,  fatty  appendages  to 
the  kidney. 

In  other  Amphibia  the  organization  of  the 
testis  is  essentially  the  same,  but  the  seminal 
coeca,  owing  to  their  greater  length,  are  tortuous 
and  convoluted. 

The  ova  are  impregnated  in  exitu  by  the 
aspersion  of  the  seminal  secretion  of  the  male, 
who,  firmly  fixed  upon  the  back  of  his  mate, 
assists  by  his  embraces  the  expulsion  of  the 
gelatinous  masses  in  which  the  eggs  are  im- 


bedded. No  organ  of  intromission,  therefore, 
is  required,  and  the  generative  ducts,  both  in 
the  male  and  female,  open  by  simple  apertures 
into  the  cloaca.  Nevertheless,  in  a  few  instances 
internal  impregnation  is  effected ;  such  is  the 
case  with  Triton,  Laurent,  in  which,  although 
no  copulation  takes  place,  the  male  fluid  dif- 
fused through  the  surrounding  water  finds  its 
way  into  the  genitals  of  the  female  in  sufficient 
quantities  to  secure  fecundation.  Moreover, 
in  the  Salamander  f  Lacerta  Salamandra )  an 
intromission  is  accomplished,  the  male  pos- 
sessing a  rudimentary  organ  for  that  purpose  ; 
in  this  latter  case  the  eggs  are  even  hatched  in 
the  oviduct  and  the  young  produced  in  the 
tadpole  state. 

In  the  other  reptiles  the  structure  and 
arrangement  of  the  generative  organs  is  very 
similar;  the  same  organization,  in  fact,  exists 
through  the  whole  class  with  slight  modifica- 
tions adapted  to  the  different  forms  or  habits  of 
different  orders. 

Fig.  207. 


The  testes  are  invariably  double,  placed 
symmetrically  on  the  two  sides  of  the  body, 
and  attached  by  membranous  connexions  to  the 
vertebral  column.  On  unravelling  their  inter- 
nal structure  they  are  found  to  consist  entirely 
of  blind  tubes  enclosed  in  a  membranous  cap- 
sule; these  seminiferous  canals  are  much  longer 
than  in  the  amphibious  tribes,  and,  conse- 
quently, present  a  tortuous  arrangement,  readily 
seen  through  the  transparent  covering  of  the 
testes  (Fig.  207.)  From  these  tubes  a  variable 
number  of  efferent  canals  proceed,  which,  after 
remaining  for  a  short  distance  enclosed  in  a  pro- 
longation of  the  tunics  of  the  testicle,  unite  into 
a  vas  deferens,  which  is  prolonged  on  each  side 
to  the  cloaca,  and  there  terminates  at  the  root  of 
the  rudimentary  penis. 

In  the  higher  Reptilia  impregnation  is  always 
effected  internally,  and  the  males  are  conse- 
quently provided  with  an  organ  of  excitement, 
differing  much  in  form,  but  invariably  imper- 
forate, being  merely  grooved  upon  its  surface 
by  a  channel,  along  which  the  semen  flows 
into  the  cloaca  of  the  female,  but  without  any 
provision  for  its  forcible  expulsion. 

This  kind  of  penis  consists  entirely  of  the 
corpora   cavernosa,   arising    by   two  crura, 


ORGANS  OF  GENERATION. 


421 


which  unite  intimately  along  the  upper  aspect 
of  the  organ,  but  leave  inferiorly  a  deep  fissure 
which  is  continued  to  the  extremity.  In  the 
Chelonia  this  organ  of  excitement  is  very  large, 
and  terminates  in  a  single  point,  but  in  many 
Saurian  and  Ophidian  species  its  extremity  is 
bifid,  each  division  being  covered  with  sharp 
and  recurved  spines,  an  arrangement  which,  in 
creatures  so  deficient  in  organs  of  prehension, 
is  evidently  adapted  to  ensure  efficient  copu- 
lation. 

In  the  females  of  these  reptiles  the  structure 
of  the  ovaria  is  interesting,  gradually  leading  us 
from  the  folds  of  vascular  membrane,  between 
which  the  numerous  eggs  of  the  Batrachia  are 
generated,  to  the  form  which  they  present  in 
Birds.  Each  ovary  assumes  a  racemose  ap- 
pearance, and  consists  of  a  number  of  ova  in 
various  states  of  perfection,  which  are  loosely 
attached  to  the  sides  of  the  vertebral  column  by 
folds  of  peritoneum.  Their  structure,  however, 
is  essentially  that  which  has  been  already  de- 
scribed, and  the  ova,  when  matured  between 
the  vascular  lamina;  of  the  ovarian  investments, 
escape,  as  in  frogs,  from  the  surface  of  these 
viscera  by  a  laceration  of  the  investing  mem- 
brane, and  would  break  loose  into  the  abdo- 
minal cavity  did  not  the  more  perfect  develope- 
ment  of  the  oviducts,  which  here  have  their 
patulous  extremities  so  disposed  that  they  can 
grasp  the  ovaria  during  excitement,  prevent  such 
an  occurrence,  by  receiving  the  germs  imme- 
diately from  the  ruptured  ovary.  The  oviducts 
are  two  in  number,  membranous  at  first,  but 
glandular  as  they  approach  their  termination 
in  the  cloaca.  In  these  the  eggs  receive  an 
albuminous  investment  which  they  absorb  in 
the  first  portion  of  the  canal,  and  prior  to  their 
expulsion  are  furnished  with  a  coriaceous  or  cal- 
careous covering  produced  from  the  thicker 
portion  of  the  oviferous  tube. 

The  females  of  the  Cliclonia  have  a  clitoris, 
or  rudiment  of  the  male  penis,  which  is  in  a 
similar  manner  provided  with  muscles  for  its 
retraction  into  the  cloaca  after  extrusion.  In 
other  Reptiles  the  clitoris  is  deficient. 

Birds  form  a  remarkable  exception  to  the 
usual  arrangement  of  the  internal  sexual  organs 
in  oviparous  vertebrate., the  ovarium  and  oviduct 
being  single  throughout  the  class,  an  organi- 
zation which  is  evidently  in  relation  with  that 
lightness  and  activity  essential  to  their  habits. 
This  deviation  from  the  usual  type,  however, 
is  only  apparent,  arising  from  the  non-develop- 
ment of  the  ovary  and  its  duct  on  one  side  of 
the  body,  although  both  exist  in  a  rudimentary 
state. 

The  ovarium,  as  in  Reptiles,  is  racemose, 
consisting  of  ova  in  different  stages  of  growth, 
each  enclosed  in  a  vascular  membrane,  which 
forms  a  pedicle  attaching  it  to  the  general 
cluster,  and  is  ruptured  by  the  escape  of  the 
germ  enclosed  within  it.  The  oviduct  is  short  in 
comparison  with  that  of  many  reptiles,  and  the 
structure  of  its  lining  membrane  indicates  the 
offices  performed  by  different  portions  of  the 
canal,  being  smooth  and  vascular  in  its  upper 
portion,  where  the  yolk  receives  its  albuminous 
covering,  but  becoming  villous  and  plicated 
where  it  secretes  the  shell. 


Male  birds,  like  reptiles,  are  furnished  with 
two  testes,  which,  from  their  comparatively  in- 
significant size,  do  not  materially  interfere  with 
the  bulk  of  the  viscera;  yet  even  these  only  as- 
sume their  full  proportions  at  stated  times, 
namely,  at  that  period  of  the  year  when  their 
office  is  required. 

The  testes  are  constantly  situated  in  the  ab- 
dominal cavity  immediately  behind  the  lungs 
and  under  the  anterior  extremity  of  the  kidney  : 
as  in  all  cases,  they  consist  of  sperm-secreting 
tubes,  but  of  such  extreme  tenuity  that  their 
diameter  was  estimated  by  Muller  as  not 
greater  than  the  0  00528  of  a  Parisian  inch. 
These  canals  are  enclosed  in  a  proper  capsule, 
which  sends  septa  into  the  interior  of  the  organ; 
they  unite  to  form  a  slightly  flexuous  vas  defe- 
rens, which  accompanies  the  ureter  of  the  cor- 
responding side.  The  vasa  deferentia  termi- 
nate by  separate  orifices  in  the  cloacal  cavity 
near  the  root  of  the  rudimentary  penis  when 
such  exists,  but  even  in  its  most  perfect  forms 
the  male  organ  is  merely  an  instrument  serv- 
ing for  the  conveyance  of  the  seminal  liquor 
along  a  groove  seen  upon  its  surface,  there 
being  as  yet  no  corpus  spongiosum  or  inclosed 
urethra  as  in  the  Mammiferous  classes,  adapted 
to  an  efficient  injection  of  the  semen  into  the 
female  parts,  nor  any  auxiliary  secretions  sub- 
servient to  the  same  purpose.  In  the  females 
of  those  genera  in  which  the  penis  is  most  de- 
veloped, a  clitoris  is  found  to  occupy  a  similar 
position. 

The  Mammalia  differ  remarkably  from  the 
other  vertebrate  classes  in  the  elaborate  deve- 
lopement  of  the  sexual  organs  in  both  sexes. 
The  increased  complication  of  these  parts  is  attri- 
butable in  the  male  to  the  necessity  for  a  much 
more  efficient  intromission  of  the  spermatic 
secretions  during  coitus,  and  in  the  female  to 
the  superadded  function  of  gestation  which 
characterizes  the  class. 

On  comparing  the  male  organs  of  Mammi- 
fera  with  those  of  the  oviparous  vertebrata, 
several  circumstances  demand  our  notice,  the 
most  striking  of  which  is  the  separation  of  the 
canals  provided  for  excretion  into  two  distinct 
systems,  each  terminating  externally  by  an 
appropriate  orifice,  thus  detaching  entirely  the 
digestive  emunctory  from  the  genito-urinary 
apparatus,  which  hitherto  we  have  found  to  dis- 
charge themselves  by  one  common  orifice  com- 
municating with  a  cloacal  cavity.  With  one 
interesting  exception  furnished  by  the  Mono- 
tremata,  such  a  separation  exists  throughout  all 
the  Mammiferous  orders.  Internally  a  still 
further  isolation  is  evident  in  the  separation  of 
the  urinary  and  generative  organs  by  the  pro- 
vision of  a  urinary  bladder,  in  which  the  secre- 
tion of  the  kidneys  is  stored  up  until  its  expul- 
sion becomes  necessary  ;  the  same  excretory 
canal,  however,  is  still  common  to  both  these 
systems.  In  the  ovipara  the  penis  was  merely 
furrowed  with  a  sulcus,  along  which  the  semen 
trickled  during  the  union  of  the  sexes  without 
being  impelled  by  any  expulsive  apparatus  ; 
but  in  the  class  of  which  we  are  now  speaking 
the  urethral  canal  becomes  surrounded  by  vas- 
cular erectile  tissue,  forming  a  complete  tube 
through  which  the  seminal  liquor  is  powerfully 


422 


ORGANS  OF  GENERATION. 


ejaculated  during  copulation  by  a  muscular 
arrangement  provided  for  that  purpose  ;  and  in 
the  last  place  the  emission  of  the  fecundating 
fluid  is  further  provided  for  by  the  addition  of 
secondary  secretions,  which  from  augmenting 
its  quantity  facilitates  its  ejection. 

We  shall  proceed  to  speak  of  these  circum- 
stances seriatim,  examining  first,  the  structure 
and  position  of  the  testis  and  its  duct;  secondly, 
auxiliary  glands  which  add  their  secretions  to 
the  seminal  liquor;  thirdly,  the  structure  of  the 
penis,  and  arrangement  of  the  organs  of  intro- 
mission. 

We  have  found  in  all  the  classes  of  verte- 
brata  of  which  we  have  hitherto  treated,  that 
the  testes  consisted  essentially  of  blind  tubes. 
In  Frogs  these  sperm-secreting  canals  were  ex- 
ceedingly short;  in  other  Amphibia  they  become 
elongated  and  flexuous.  In  Reptiles  their 
length  and  convolution  was  still  further  in- 
creased, until  at  length  in  Birds  and  Mamma- 
lia their  length  is  so  great,  and  their  delicacy 
so  excessive,  that  they  are  with  difficulty  unra- 
velled. In  all  animals  the  terminations  of  the 
seminal  tubes  are  found  to  be  closed,  neither  is 
any  increase  or  diminution  perceptible  in  the 
diameter  of  one  of  these  vessels  throughout  its 
whole  course.  Another  circumstance  which, 
with  one  or  two  exceptions,  is  common  to  all 
Mammals,  is  that  they  never  ramify  or  divide.* 

Mammalia  differ  much  amongst  each  other 
as  regards  the  length,  number,  convolutions, 
and  general  arrangement  of  these  secerning 
vessels  of  the  testis.  In  the  Ass  they  are  very 
delicate;  of  greater  diameter  in  the  Cynoce- 
phalus  and  larger  Carnivora,  as  well  as  in  the 
Hog  and  Rhinoceros.  They  are  very  large  in 
the  Glire$,  and  in  Sciurus  their  diameter 
reaches  -0-01453  inch  (Paris),  whilst  in  the 
Hedgehog  they  are  only  0-00970  inch. 

The  tenuity  of  the  walls  of  these  seminal 
vessels  is  extreme,  and  scarcely  applicable  by 
the  micrometer ;  they  are  united  together  by  a 
most  delicate  tissue  of  capillary  bloodvessels, 
serving  to  imbue  them  with  that  blood  from 
which  the  semen  is  separated,  which  when  se- 
creted accumulates  in  the  cavities  of  these  tubes 
in  readiness  for  expulsion. 

The  testes  are  very  variously  situated  in  the 
adult  state  of  different  mammals.  Sometimes 
they  are  contained  within  the  abdominal  cavity, 
attached  on  each  side  of  the  spinal  column  by 
folds  of  the  peritoneum,  as  in  the  ovipara ;  at 
other  times  they  descend  into  the  skin  of  the 
groin  through  the  inguinal  canal,  and  not  un- 
fiequently  are  contained  in  a  scrotal  pouch 
formed  by  the  integument  behind  the  pubic 
arch ;  and  in  the  Marsupial  division,  which, 
when  describing  the  female  sexual  organs,  we 
shall  find  to  constitute  a  distinct  type  of  the 
generative  system,  they  are  suspended  in  front 
of  the  pelvis. 

The  excretory  duct  of  each  testis  or  vas  de- 
ferens is  formed  by  the  junction  of  the  seminal 
canals  of  the  testis  ;  it  is  at  first  much  convo- 
luted, forming  a  mass  appended  to  the  testicle, 
denominated  the  epididymus ;  and  whatever 

*  In  Sciurus  they  have  been  observed  to  divide 
dichotomously. 


may  be  the  position  of  the  testicle,  it  runs  to 
discharge  itself  into  the  canal  of  the  urethra 
near  the  commencement  of  that  tube. 

The  prostate  gland  is  a  secreting-  body  of  pe- 
culiar structure,  which,  in  man,  embraces  the 
neck  of  the  bladder,  and  opens  by  ten  or  twelve 
ducts  into  the  urethra  near  its  commencement. 
It  is  very  constant  in  its  existence,  being  found 
in  all  orders  of  Mammalia,  excepting,  perhaps, 
the  greater  number  of  the  Rodentia,  the  Mole, 
and  the  Hedgehog,  in  which  it  is  apparently 
replaced  by  secerning  organs  of  a  widely  dif- 
ferent structure;  otherwise,  the  internal  organi- 
zation of  this  gland  is  nearly  the  same  in  all 
animals  that  possess  it,  consisting  essentially 
of  cells,  each  of  which  is  subdivided  into  others 
of  extreme  minuteness.  From  these  cells  the 
excretory  ducts  take  their  rise,  and  the  whole 
organ  may  be  readily  inflated  by  forcing  air  into 
the  canals  which  issue  from  it :  the  whole  is 
enclosed  in  a  dense  fibrous  capsule.  In  some 
animals,  as  the  Elephant  and  Solipeds,  the 
prostate  is  double  or  even  quadruple,  and  in 
this  case  the  centre  of  each  portion  has  within 
it  a  large  cavity  which  communicates  with  the 
smaller  cells,  and  gives  origin  to  the  excretory 
tube. 

Coivpers  glands. — These  glands  in  the  hu- 
man subject  are  two  very  small  bodies  situated 
behind  the  bulb  of  the  urethra,  which  furnish 
minute  canals,  opening  obliquely  into  the  urino- 
generative  canal  near  its  posterior  portion ;  but 
minute  as  they  are  in  man,  they  are  found  in 
other  creatures  to  be  much  more  voluminous, 
net  unfrequently  equalling  the  prostate  in  size, 
and  in  some  cases,  especially  in  the  Marsupial 
division,  they  are  increased  in  number ;  thus 
in  the  Opossums  and  Kangaroo-rat  there  are 
four,  while  in  the  Wombat  ( Fhascolomys), 
the  Kangaroo,  and  others,  even  six  are  found : 
nevertheless  in  most  of  the  Carnivora,  except 
the  Felidae  and  Hyenas,  and  in  the  greater 
number  of  Ruminants,  Solipeds,  Amphibia, 
and  Cetacea,  they  are  deficient. 

The  internal  structure  of  Coivpers  glands 
varies.  In  man  and  many  others  they  are 
composed  of  simple  follicles  ;  in  other  cases, 
as  in  Sciurus,  the  Marmot  and  the  Hog,  they 
consist  of  conical  sacculi,  which  exhibit  in- 
ternally a  cellular  appearance.  In  the  Beaver 
(Castor  Fiber )  their  texture  is  spongy,  being 
formed  of  large  cells,  divided  by  septa  into 
smaller  ones  of  extreme  minuteness  ;  those  of 
the  Mole  are  similarly  constructed.  In  Vi- 
verra  Zibetha,  the  feline  tribes  and  the  Hyena, 
they  are  made  up  of  separate  lobules ;  and 
in  the  Ichneumon  these  glands  are  composed 
of  vesicles  united  by  a  common  duct.  In 
the  Hedgehog  ( Erinaceus  Europceus)  they  are 
found  in  a  very  singular  position,  being  partly 
situated  beneath  the  rami  of  the  pubis  and 
ischium,  and  partly  beneath  the  skin  on  the 
inner  side  of  the  thigh,  being  so  remote  from 
the  other  glands  that  their  existence  was  over- 
looked by  Cuvier.  Each  gland  consists  of 
pyramidal  lobules,  which,  by  their  apices, 
give  rise  to  the  excretory  canals. 

In  some  of  the  Marsupiata  their  minute 
structure  resembles  what  is  found  in  the  Hedge- 
hog; and  each  of  them  is  surrounded  by  a 


ORGANS  OF  GENERATION. 


423 


powerful  muscular  sheath,  calculated  to  en- 
sure the  expulsion  of  tha  fluid  which  they 
elaborate. 

The  most  remarkable  arrangement  cf  Cow- 
per's  glands  is  seen  in  the  Ichneumon  ( Her- 
pestes  Ichneumon,  Illiger):  in  this  animal  they 
are  very  large  and  occupy  their  usual  position, 
being  invested  with  v.  strong  muscular  coat; 
but  their  excretory  ducts,  instead  of  termi- 
nating as  usual  in  the  bulbous  portion  of  the 
urethra,  are  prolonged  beneath  the  penis  nearly 
to  the  extremity  of  that  organ,  where  they 
open  into  a  cul-de-sac  common  to  them  and 
the  canal  of  the  urethra. 

Accessor!/  vesicles.  —  These  are  auxiliary 
glands,  which  pour  their  secretions  into  the 
canal  of  the  urethra.  They  appear,  when 
present,  to  take  the  place  of  the  prostate, 
being  only  found  where  that  organ  is  deficient, 
and  accordingly,  although  of  a  totally  different 
structure  from  that  body,  they  have  been  called 
prostates  by  various  authors.  They  are  usually 
packets  of  membranous  cceca,  more  or  less  ra- 
mified, and  in  the  season  of  sexual  excitement 
are  filled  with  a  fluid  resembling  that  contained 
in  the  vesiculae  seminales.  These  organs  exist 
in  all  Rodents  except  Squirrels,  Marmots,  and 
Hares,  and  also  in  the  Hedgehog  and  the 
Mole,  but  have  not  been  found  in  any  other 
mammalia.  They  are  invariably  composed 
of  intestinules  or  branched  cceca,  arranged  in 
packets,  the  number  of  which  varies  much. 
Thus  ia  the  Mole  there  are  five  such  bundles, 
forming  a  mass  of  ramified  tubes  larger  than 
the  bladder  ;  in  the  Hedgehog  there  are  four, 
and  in  Cricetus  vulgaris  and  Dasyproeta 
Aguti  two  fasciculi. 

But  besides  the  secreting  structures  above 
enumerated  as  forming  the  ordinary  appendages 
to  the  male  generative  system  of  Mammifers, 
additional  ones  are  occasionally  found,  placed 
out  of  the  positions  in  which  the  succenturiate 
glands  usually  exist.  Thus  in  Solipeds  a  long 
ccecum  containing  a  glairy  fluid  is  placed  be- 
tween the  insertions  of  the  vasa  deferentia, 
which  communicates  with  the  urethra  by  an 
appropriate  orifice;  and  in  Cricetus  and  manv 
of  the  Murida:  the  ends  of  the  deferent  canals 
before  their  termination  are  provided  with 
bunches  of  small  glandular  follicles,  which  in 
the  former  resemble  small  bunches  of  grapes. 


The  annexed  figure,  (fig.  208,)  representing 
the  male  generative  viscera  of  the  Hat  ( Mus 
liattus)  exhibits  an  example  of  the  greatest  com- 
plication of  these  parts,  and  will  serve  to  illus- 
trate the  situation  of  the  organs  above  described. 
A  represents  the  bladder  turned  forwards,  B  the 
rectum,  and  C  the  testis  of  the  left  side.  The 
succenturiate  glands  here  found  are  a,  a,  the 
vesiculic  seminales ;  b,  the  anterior  fasciculus  of 
the  accessory  vesicles  or  anterior  prostate  of 
some  authors,  which  on  the  opposite  side  is  un- 
ravelled to  display  the  cceca  which  compose  it; 
c,  the  middle  prostatic  cceca;  d,  the  anterior 
prostatic  cceca.  These  all  communicate  with 
the  urethra,  and  in  addition  to  these  we  have 
on  each  side  the  racemose  bunch  of  follicles  (e) 
which  is  appended  to  the  termination  of  the 
vas  deferens  (  /'). 

Structure  of  the  penis. — The  great  difference 
between  the  penis  of  Mammifers  and  that  which 
has  been  described  as  existing  in  the  oviparous 
vertebrata,  consists  in  theinclosure  of  the  canal 
of  the  urethra,  which  is  no  longer  a  simple 
groove  formed  by  the  junction  of  the  corpora 
cavernosa,  but  becomes  surrounded  with  a  cy- 
linder of  erectile  tissue  usually  denominated 
the  corpus  spongiosum  urethra.  The  corpus 
cavcrnosum,  which  generally  forms  the  great 
bulk  of  the  organ,  arises  by  two  crura,  which  are 
firmly  attached  to  the  rami  of  the  ischium  in 
the  males  of  all  placental  Mammalia;  and  even 
in  the  Cetacea,  where  there  is  no  pelvis,  two 
bones  placed  on  each  side  of  the  corpus  caver- 
nosum  give  a  support  to  the  penis,  which  is 
attached  to  them  by  fibrous  ligaments ;  never- 
theless, in  the  Marsupiata  the  crura  of  the 
corpus  cavernosum  are  quite  free,  or  only 
loosely  attached  to  the  ischiadic  bones  by 
the  muscular  sheaths  in  which  they  are  en- 
veloped. The  crura  of  the  corpora  cavernosa 
unite  to  form  the  body  of  the  penis,  their 
union  being  generally  marked  by  a  strong 
septum,  which  more  or  less  completely  divides 
the  organ  into  two  lateral  halves.  In  some 
animals,  as  in  the  Dog,  this  septum  is  very 
distinct ;  but  in  other  cases,  especially  in  many 
of  the  Plantigrade  Carnivora  and  in  most  of  the 
Pachydermatous  and  Cetaceous  tribes  such  a 
partition  is  entirely  wanting;  in  such  cases  the 
fibrous  lamellae,  which  arise  from  the  dense 
capsule  surrounding  this  portion  of  the  penis, 
and  traverse  the  vascular  tissue  which  is  con- 
tained in  its  interior,  unite  at  a  central-  part  in 
a  kind  of  cord  formed  by  their  union.  In 
some  anima's  the  organ  is  supported  by  a  bone 
developed  in  its  interior:  this  arrangement 
exists  in  the  Quadruniana,  Cheiroptera,  the 
lJluntigrade  and  Digitigrade  Carnivora  (ex- 
cept the  Hyaena),  and  in  the  Rodentia,  also  in 
Seals  and  Cetaceans.  In  a  few  instances  it  is 
so  large  as  to  form  a  large  portion  of  the  penis, 
as  in  Whales  ;  in  others,  as  in  many  Carnivora 
and  Rodentia,  it  is  extremely  small,  but  what- 
ever its  form  or  size  it  is  invariably  found  in- 
timately connected  with  the  corpus  caverno- 
sum. 

The  urethra,  as  in  man,  consists  of  a  mus- 
cular and  of  a  vascular  portion,  the  former 
receiving  the  ducts  of  the  succenturiate  and 


424 


GENERATION. 


seminal  glands,  the  latter  embedded  in  the 
erectile  tissue  of  the  corpus  spongiosum.  The 
muscular  portion  does  not  always  join  the  vas- 
cular part  in  a  straight  line  ;  but,  on  the  con- 
trary, in  some  animals,  as  in  Ruminants  gene- 
rally and  in  the  Boar,  the  former  opens  by  an 
orifice  perforated  in  the  upper  wall  of  the 
latter,  at  a  little  distance  from  its  commence- 
ment, so  that  a  c  ul-de-sac  is  left  excavated  in 
the  bulb  of  the  urethra  or  commencement  of 
the  spongy  portion,  in  which  the  fluids  poured 
into  the  muscular  part  are  mixed  with  the  se- 
cretion of  Cowper's  glands,  which  enters  the 
sides  of  the  excavation. 

In  Squirrels  and  Marmots  a  similar  cul-de- 
sac  exists,  which  only  receives  the  secretion  of 
Cowper's  glands,  and  is  continued  forwards 
as  a  narrow  tube  surrounded  by  vascular  tissue, 
beneath  the  urethra,  as  far  as  the  middle  of  the 
penis,  where  the  two  canals  unite. 

The  course  of  the  urethra  in  the  great  Kan- 
garoo ( Macropus  major)  is  peculiar;  instead 
of  passing,  as  is  usually  the  case,  beneath  the 
corpus  cavernosum,  it  is  inclosed  in  a  canal 
passing  through  the  centre  of  the  penis,  from 
which  it  only  emerges  at  the  extremity  of  the 
glans ;  owing  to  this  arrangement,  the  spongy 
investment  of  the  canal  is  in  this  animal  con- 
founded with  the  vascular  tissue  of  the  corpus 
cavernosum. 

In  others  of  the  Marsupiata  the  corpus  spon- 
giosum, like  the  cavernous  body,  arises  by  two 
crura,  which  are  quite  unattached,  each  being 
invested  with  a  strong  muscular  sheath,  and 
even  in  some  placental  Mammals,  as  the  Water- 
rat  and  the  Camel,  rudiments  of  this  division 
are  distinguishable. 

The  glans  penis,  or  extremity  of  the  intro- 
mittent  organ,  presents  many  modifications  in 
form  and  in  the  nature  of  its  surface.  It  is 
frequently  smooth  and  highly  sensible,  as  in 
man,  being  only  covered  by  a  delicate  skin ; 
yet  in  other  instances,  as  in  the  feline  Carni- 
vora,  it  is  armed  with  stiff  recurved  bristles  ; 
sometimes  the  armature  represents  horny  scales 
or  strong  spines,  and  in  not  a  few  genera  we 
find  horny  serrated  plates  projecting  from  its 
surface;  and,  as  though  these  formidable  saws 
were  insufficient,  they  are  occasionally  com- 
bined with  horny  prongs  protruded  from  the 
extremity  of  the  penis  during  its  erection. 
These  last  appendages  are  found  in  various 
families  of  the  Rodentia,  as  in  Guinea-pigs 
and  Agoutis.  The  limits  of  this  article  will 
not  permit  us  to  expatiate  further  on  this  part 
of  our  subject;  we  must  therefore  refer  the 
reader  for  a  description  of  the  various  forms  of 
the  penis  and  of  the  muscles  belonging  to  that 
organ  to  the  articles  which  treat  of  the  Mam- 
miferous  orders  individually. 

The  female  Mammalia  exhibit  in  their  gene- 
rative system  a  beautiful  gradation  of  struc- 
ture. They  naturally  divide  themselves  in 
conformity  with  their  mode  of  gestation  into 
two  classes,  viz.  the  Ovo-vivipara  or  Marsu- 
piata, and  the  Viviparu,  properly  so  called, 
comprising  the  placental  orders. 

The  former  division  approximates  in  every 
particular  to  the  oviparous  type  of  structure  : 


the  ovaria  are  racemose,  as  in  birds;  the  ovi- 
ducts, which  now  assume  the  name  of  uteri,  are 
still  double,  opening  by  distinct  orifices  into 
the  vagina,  which  also  is  not  unfrequently  di- 
vided. But  the  great  feature  which  distin- 
guishes the  ovo-viviparous  mammals  is  the 
peculiar  apparatus  in  which  gestation  is  com- 
pleted, the  embryo  being  expelled  from  the 
uterus  at  a  very  early  period,  without  ever  con- 
tracting any  vascular  connexion  with  that  organ, 
to  be  lodged  in  a  marsupium  or  pouch  con- 
nected with  the  abdomen  of  the  mother,  in 
which  the  nipples  are  contained.  In  this  situ- 
ation it  becomes  attached  by  its  mouth  to  one 
of  the  teats,  and  thus  derives  from  the  mam- 
mary secretion  the  nourishment  essential  to  its 
growth. — See  Marsupiata. 

In  the  Placental  division  gestation  is  com- 
pleted within  the  uterine  cavity  by  the  deve- 
lopment of  a  vascular  mass  of  different  con- 
struction in  different  classes,  called  the  Pla- 
centa. The  ovaria  here  gradually  lose  their 
racemose  appearance,  and  are  converted  into 
small  and  solid  masses,  in  which  the  ova  or 
Graafian  vesicles  are  evolved.  The  uterus,  at 
first  completely  divided,  as  in  some  of  the 
Rodentia,  in  which  the  two  cornua  open  se- 
parately into  a  single  vaginal  canal,  by  degrees 
unites,  and  by  a  progressive  coalescence  attains 
that  concentration  most  perfectly  exhibited  in 
the  human  female. 

To  enter  more  largely  into  details  connected 
with  the  generative  organs  of  the  Mammiferous 
classes  would  needlessly  swell  the  bulk  of  this 
article,  in  which  our  object  has  been  to  lay 
before  the  reader  a  connected  view  of  the  mo- 
difications met  with  in  the  reproductive  system 
throughout  the  animal  kingdom,  and  thus  to 
connect  with  each  other  the  numerous  facts 
relating  to  this  subject  which  are  elsewhere 
more  minutely  recorded  in  this  work. 

For  the  anatomy  of  the  Organs  of  Generation  in 
Man,  see  PENIS,  PROSTATE,  TESTIS,  VESlCUL^E 
SEMINALES. 

(  T.  Rymer  Jones.) 

GENERATION  (in  Physiology)  generatio; 
Fr.  generation;  Germ.  Zeugung ;  Ital.  gene- 
razione;)  is  the  process  by  which  the  young 
of  living  bodies  are  produced,  and  their  spe- 
cies continued.  In  common  language  the 
term  is  frequently  confined  to  the  mere  act  of 
union  of  the  sexes  of  animals;  but  in  general 
and  animal  physiology  it  is  generally  employed 
in  the  more  extended  signification  given  to  it 
in  the  following  article,  viz.  to  denote  the  assem- 
blage of  all  the  functions  of  animals  concerned 
in  the  formation  of  their  young,  and  as  syno- 
nymous, therefore,  with  the  function  of  Repro- 
duction. 

In  directing  our  attention  to  the  mode  in 
which  the  function  of  reproduction  is  effected 
in  various  classes  of  animals,  so  many  striking 
differences  present  themselves,  that  we  find  it 
difficult  if  not  impossible  to  point  out  any 
general  circumstances  in  respect  to  which  they 
all  agree.  Some  animals,  for  example,  are 
propagated  by  the  division  of  their  whole 
bodies  into  pieces,  each  of  which  by  a  pecu- 


GENERATION. 


425 


liar  change  becomes  an  independent  individual 
entering  upon  a  new  life.  Others  arise  like 
the  parts  of  a  tree  by  buds  which  remain  for 
a  time  attached  to  the  parent  stem,  and  being 
afterwards  separated  from  it  assume  an  inde- 
pendent existence.  A  third  class  of  animals 
have  the  power  of  forming  and  throwing  off 
from  their  bodies  a  small  portion  of  organized 
matter,  which,  though  at  the  time  of  its  sepa- 
ration from  the  parent,  not  resembling  it  either 
in  form  or  organization,  is  yet  possessed  of  the 
power  of  living  for  itself,  and,  after  passing 
through  a  variety  of  successive  changes  of 
growth  and  evolution,  of  at  last  acquiring  the 
exact  semblance  of  the  parent  by  which  it  was 
produced.  In  a  fourth  and  last  class,  com- 
prehending much  the  greatest  number  of  ani- 
mals, the  function  of  reproduction  involves  a 
greater  complication  of  vital  processes  than  in 
the  three  other  classes  above  alluded  to.  The 
union  of  two  individuals  of  different  sex  be- 
comes necessary,  and  the  young  owe  their 
origin  to  the  evolution  of  a  more  complex 
organized  structure  termed  the  egg,  which  is 
formed  in  and  separated  from  the  body  of  the 
female  parent,  and  is  the  product  of  the  union 
of  the  male  and  female  of  all  animals  in  which 
the  distinction  of  sex  exists.  The  ovum  or  egg 
is  most  familiarly  known  to  us  in  the  eggs  of 
domestic  birds,  to  which  the  product  of  sexual 
union  in  all  animals  belonging  to  this  fourth 
class  bears  a  strict  analogy  in  every  essential 
particular. 

It  may  be  stated  as  a  general  fact,  that  the 
reproductive  function  involves  a  greater  num- 
ber of  vital  processes  in  the  higher  and  more 
complicated  than  in  the  lower  and  simpler 
kinds  of  animals.  Yet  there  are  exceptions 
to  this  rule,  and  we  do  not  always  trace  a 
correspondence  between  the  degree  of  com- 
plication of  the  generative  process  of  any 
animal  and  the  place  which  that  animal  holds 
in  the  scale  of  being ;  for  there  are  some  tribes 
of  animals  which  are  propagated  in  more  than 
one  of  the  ways  above  mentioned,  and  there 
are  some,  to  which,  from  the  simplicity  of  their 
other  functions  and  organization,  a  low  place 
in  the  zoological  scale  has  been  assigned,  and 
which  nevertheless  resemble  the  higher  animals 
in  respect  to  their  mode  of  reproduction. 

A  very  superficial  view,  however,  of  the  vari- 
eties of  the  form  obvious  in  the  reproductive 
process  of  different  animals  demonstrates  the 
importance  of  the  reproductive  functions  in  the 
economy  of  life,  as  it  points  out  the  intimate 
relation  which  these  functions  bear  to  the 
habits,  mode  of  life,  and  organization  of  each 
animal,  and  shews  the  infinite  care  and  fore- 
sight with  which  nature,  in  every  variety  of 
circumstance,  has  provided  for  the  regular  and 
undisturbed  performance  of  those  acts  by 
which  the  species  of  organize  1  beings  are  con- 
tinued from  age  to  age,  in  an  undeviating  suc- 
cession of  generations.  These  facts  also  fully 
justify  our  regarding,  along  with  Cuvier,  the 
reproductive  function  as  constituting  one  of 
the  fundamental  divisions  in  a  classification  of 
the  processes  of  the  animal  economy. 

While,  therefoie,  the  principal  object  of  the 

VOL.  II. 


present  article  is  to  describe  the  process  of 
generation  in  Man  and  the  higher  Vertebrated 
animals,  it  will  be  necessary  and  proper  for  us 
to  allude  also  to  the  reproductive  function  as 
it  is  performed  in  all  the  various  members  of 
the  animal  series ;  for  in  this,  as  in  other  de- 
partments of  Physiology,  the  more  complicated 
forms  of  the  process  derive  much  illustration 
from  the  study  of  the  more  simple,  and  we 
may  hope  thus  more  fully  to  point  out  the 
general  importance  of  the  functions  now  under 
consideration. 

We  purpose  to  follow  an  arrangement 
adapted  chiefly  to  the  consideration  of  Human 
Generation.  In  all  the  animals  in  which  dis- 
tinction of  sex  subsists,  the  male  and  female 
organs  subservient  to  reproduction  must  co- 
operate for  the  completion  of  the  generative 
process;  and  in  the  greater  number  of  the  more 
perfect  animals,  as  also  in  Man,  the  two  kinds 
of  sexual  organs  being  placed  on  separate  in- 
dividuals of  the  same  species,  the  concurrence 
of  both  these  individuals,  or  of  both  male 
and  female  parents,  is  necessary  for  the  for- 
mation of  the  fruitful  products  from  which 
the  offspring  proceeds.  The  circumstances, 
then,  which  give  rise  to  the  union  of  the  sexes 
and  the  phenomena  which  accompany  that 
union,  form  some  of  the  topics  of  the  present 
article.  The  product  of  fruitful  sexual  union 
in  all  animals  is  one  or  more  eggs,  from  each  of 
which,  under  the  influence  of  certain  favourable 
circumstances,  different  in  different  tribes,  the 
young  animal  is  produced  by  an  intricate  pro- 
cess of  vital  growth.  The  greater  part  of  the 
substance  composing  the  egg  is  furnished  by 
the  female  parent :  but  this  egg  of  the  female 
would  be  wholly  barren,  or  would  not  undergo 
any  of  those  changes  by  which  the  young 
animal  is  formed,  unless  it  received  irfsome 
way  or  other  the  influence  of  the  product  of 
the  generative  organs  of  the  male ;  and  the  egg 
formed  by  the  female  may  be  regarded  as  im- 
perfect until  the  change  now  alluded  to  has 
been  effected  in  it.  It  is  then  said  to  be 
fecundated  or  rendered  fruitful  by  the  semen 
of  the  male.  The  mode  of  formation  of  the 
egg  and  seminal  matter,  the  mode  of  their 
separation  from  the  place  of  their  formation, 
the  structure  and  properties  of  each  of  these 
products,  the  manner  in  which  they  are 
brought  together,  the  influence  which  they 
exert  upon  one  another,  and  the  consequent 
result  in  the  production  of  the  young,  con- 
stitute the  principal  remaining  topics  which 
fall  to  be  discussed  by  us  at  present.  In  this 
article  our  attention  must  chiefly  be  confined 
to  such  operations  or  functions  of  the  male 
and  female  parents  as  are  preliminary  to  or 
necessary  for  the  formation  of  a  ripe  and  fruit- 
ful ovum, — that  is,  an  egg  capable  of  giving 
birth  to  a  new  animal  the  same  as  either  of  its 
parents,  when  placed  in  those  circumstances 
which  are  favourable  to  its  evolution.  It  is 
not  intended  to  speak  in  this  place  of  the 
changes  of  the  ovum  itself  in  which  the  for- 
mation of  the  young  animal  consists  :  the 
consideration  of  these  is  reserved  for  the  article 
Ovum. 

2  F 


426 


GENERATION. 


Before  treating  in  detail  of  Human  Gene- 
ration, we  introduce  some  remarks  on  the 
nature  of  the  reproductive  function  in  general, 
and  a  sketch  of  the  principal  varieties  of  the 
forms  it  assumes  in  different  classes  of  ani- 
mals. 

I.    THE    FUNCTION   OF  REPRODUCTION  GENE- 
RALLY CONSIDERED. 

1.  Introductory  remarks. — The  process  by 
which  the  young  of  animals  are  formed  has, 
from  the  earliest  periods  of  science,  always 
been  an  object  of  peculiar  interest  and  atten- 
tion to  inquirers  into  the  functions  of  animated 
beings.  Scientific  men  as  well  as  the  more 
ignorant  have  looked  with  a  mixed  feeling  of 
wonder  and  admiration  upon  the  intricate 
changes  which  precede  and  accompany  the 
first  appearance  and  gradual  formation  of  all 
the  different  textures  and  organs  belonging  to 
animal  bodies.  The  gradual  construction  or 
building  up  of  the  whole  frame-work  of  the 
animal  body,  and  its  various  important  organs, 
— the  formation  of  the  nerves  and  brain  that 
feel  and  think,  the  muscles  that  move,  the 
blood  with  its  containing  organs  that  propel  it 
and  apply  it  to  the  purposes  of  nutrition, — 
the  appearance  step  by  step  of  all  the  remark- 
able structures  out  of  which  the  different 
organs  are  formed, — the  development  of  the 
appropriate  vital  powers  of  each  of  them, — 
the  comparatively  simple  structure  of  the  sub- 
stance of  the  egg,  and  the  impossibility  of 
detecting  in  it  by  the  most  exact  scrutiny, 
before  the  commencement  of  the  formative 
process,  any  appearance  of  the  parts  after- 
wards arising  there — have  naturally  led  phy- 
siologists to  inquire  minutely  into  the  pro- 
perties of  that  egg,  and  the  process  by  which 
so  remarkable  a  production  is  generated.  The 
ascertained  fact  that  the  egg  possesses  vital 
powers  belonging  to  itself,  and  that  its  life  is 
in  a  great  measure  independent  of  that  of  its 
parents, — that  the  vital  powers  of  the  egg  are 
capable  of  being  called  into  operation  and  in- 
fluenced in  many  animals  by  determinate 
external  physical  agents,  such  as  heat,  air, 
light,  and  electricity, — the  obscure  nature  of 
the  influence  exerted  by  the  male  upon  the 
female  product  in  the  perfecting  of  the  egg, — 
the  preservation  of  the  specific  distinctions  of 
animals  from  one  generation  to  another  in  un- 
deviating  succession, — the  transmission  of  oc- 
casional varieties  or  peculiarities  of  form  and 
of  hereditary  resemblances  from  parent  to 
offspring, — and,  in  fine,  the  important  relation 
which  the  generative  process  bears  to  other 
functions  of  the  animal  economy,  are  among 
the  more  prominent  circumstances  which, 
while  they  throw  a  certain  air  of  mystery  over 
the  functions  of  reproduction,  have  at  the  same 
time  given  them  an  interest  in  the  eyes  of  the 
physiologist,  which  increases  as  his  acquaint- 
ance with  their  details  becomes  more  ex- 
tended. 

It  is  a  common  remark  that  generation  is  at 
once  the  most  obscure  and  the  most  wonderful 
of  the  processes  occurring  in  organized  bodies. 
Hence,  perhaps,  it  has  happened  that,while  there 


are  few  subjects  of  physiological  inquiry  upon 
which  so  many  authors  have  written,  there  is  none 
upon  which  so  many  have  freely  indulged  their 
fancies  in  framing  unwarranted  hypotheses  and 
absurd  speculations.  This  is  an  error  which 
belongs  to  the  early  stage  of  investigation  in 
most  branches  of  natural  knowledge,  and 
which  in  the  instance  before  us  may  be  traced 
very  directly  to  the  comparative  want  of  cor- 
rect information  which  for  a  long  time  pre- 
vailed regarding  the  phenomena  of  the  gene- 
rative processes.  For,  if  we  except  the  re- 
markable investigations  of  Aristotle,  Fabricius, 
Harvey,  Malpighi,  Wolff,  and  Haller,  it  may 
be  said  that  it  is  only  towards  the  conclusion 
of  the  last  or  the  commencement  of  the  pre- 
sent century  that  our  subject  has  been 
studied  with  that  accuracy  of  observation  and 
freedom  from  hypothesis  which  are  calcu- 
lated to  insure  steady  progress  in  the  attain- 
ment of  physical  knowledge.  When  ex- 
tended observation  shall  have  rendered  more 
familiar  to  the  physiologist  the  different  steps 
of  the  intricate  processes  by  which  an  egg  is 
formed  and  the  young  animal  is  developed 
from  it,  although  he  may  not  cease  to  admire 
the  changes  in  which  these  processes  consist, 
the  feeling  of  wonder  will  be  in  a  great  mea- 
sure lost  to  him  ;  and  he  will  not  be  inclined 
to  look  upon  the  gradual  formation  and  growth 
of  the  child  as  more  extraordinary  than  the 
constant  and  regular  nutrition  of  the  fully 
formed  body.  Are  the  inscrutable  workings 
of  the  brain  and  nerves,  the  constant  energy 
of  the  beating  heart,  the  unwearied  and  pow- 
erful exertions  of  the  voluntary  muscles,  the 
secretion  of  different  fluids  from  the  glands, 
and  the  regular  supply  of  suitable  organic 
materials  to  all  parts  of  the  body,  so  as  to 
maintain  the  healthy  structure  of  each  and  fit 
them  for  the  performance  of  their  respective 
offices,  less  remarkable  and  astonishing,  or, 
in  other  words,  less  far  removed  from  our 
accurate  knowledge  and  comprehension,  than 
the  first  origin  and  early  growth  of  the  same 
organs  at  a  time  when  both  their  structure  and 
functions  are  greatly  more  simple?  Certainly 
not.  These  remarkable  changes  are  all  objects 
of  wonder  to  the  vulgar  in  proportion  as  they 
are  unknown.  The  man  of  science  regards  the 
ultimate  cause  of  all  vital  processes  as  equally 
inexplicable,  and,  aware  of  the  bounds  set  to 
his  knowledge  of  life,  limits  his  inquiries  con- 
cerning its  various  processes  to  the  investigation 
of  their  phenomena. 

At  the  same  time  it  may  be  allowed  that  the 
fact  that  the  mere  contact  of  the  male  seminal 
fluid  seems  to  awaken  and  call  forth  from  the 
otherwise  inanimate  egg  all  those  vital  powers 
which  are  afterwards  concerned  in  sustaining 
the  life  of  the  new  being,  is  one  of  the  most 
striking  and  simple  examples  of  vital  agency, 
and  one  less  suited  than  most  others  to  be 
observed  or  experimentally  investigated.  The 
theoretical  physiologist,  in  contemplating  this 
fact,  is  apt  to  conceive  that  here  he  has  ar- 
rived at  one  of  tbf  primitive  causes  or  foun- 
dations of  animal !  fe,  and  that  he  has  here 
obtained  the  key;     many  of  its  hidden  won- 


GENERATION. 


427 


ders :  he  passes  the  limits  which  ought  to 
-  bound  his  inquiries,  and  in  most  instances 
invents  fanciful  and  curious  speculations  rather 
than  makes  sound  generalizations  of  ascer- 
tained facts. 

2.  Theories  of  generation. — The  vast  num- 
ber of  the  theories  of  generation  renders  it 
impossible  to  mention  even  the  more  im- 
portant in  this  place.  Drelincourt,  an  author 
of  the  last  century,  brought  together  so  many 
as  two  hundred  and  sixty-two  "  groundless 
hypotheses"  concerning  generation  from  the 
writings  of  his  predecessors,  "  and  nothing  is 
more  certain,"  quaintly  remarks  Blumenbach, 
"  than  that  Drelincourt's  own  theory  formed 
the  two  hundred  and  sixty-third."* 

Of  these  theories  two  principal  classes  may 
be  distinguished,  according  as  they  more  di- 
rectly relate,  1st,  to  the  action  of  the  parent 
organs,  or  2d,  to  the  changes  in  the  egg 
belonging  to  the  formation  of  the  new  animal. 
Of  the  first  of  these  classes  of  theories  Haller 
made  three  divisions,  according  as  the  offspring 
is  supposed  to  proceed,  1st,  exclusively  from 
the  organs  of  the  male  parent,  2d,  entirely  from 
those  of  the  female,  or  3d,  from  the  union  of 
the  male  and  female  products.  The  second 
class  of  these  theories,  that,  viz.  which  relates 
more  particularly  to  the  formation  of  the  new 
animal,  may  be  arranged  under  two  heads, 
according  as  the  new  animal  is  supposed,  1st, 
to  be  newly  formed  from  amorphous  materials 
at  the  time  when  it  makes  its  appearance  in 
the  egg,  or  2d,  to  have  its  parts  rendered 
visible,  by  their  being  expanded,  unfolded,  or 
evolved  from  a  previously  existing  though  in- 
visible condition  in  the  germ. 

The  greater  number  of  the  older  theories  of 
generation  may  then  be  brought  under  one  or 
other  of  the  above-mentioned  divisions,  viz. 
the  theory  of  the  Ovists,  of  the  Spermatists, 
that  of  Combination,  Evolution  or  Epigenesis. 

According  to  the  first-mentioned  of  these 
hypotheses,  or  that  of  the  Ovists,  the  female 
parent  is  held  to  afford  all  the  materials  neces- 
sary for  the  formation  of  the  offspring,  the 
male  doing  no  more  than  awakening  the  forma- 
tive powers  possessed  by,  and  lying  dormant 
in,  the  female  product.  This  was  the  theory 
of  Pythagoras,  adopted  in  a  modified  form  by 
Aristotle ;  and  we  shall  afterwards  see  that  it 
resembles  most  closely  the  prevailing  opinion 
of  more  modern  times.  The  terms,  however, 
in  which  some  of  the  older  authors  expressed 
this  theory  are  very  vague,  as,  for  example,  in 
the  notion  that  the  embryo  or  new  product 
"  is  formed  from  the  menstrual  blood  of  the 
female,  assisted  by  a  sort  of  moisture  descend- 
ing from  the  brain  during  sexual  union." 

According  to  the  second  theory,  or  that  of 
the  Spermatists,  among  the  early  supporters  of 
which  Galen  maybe  reckoned,  it  was  supposed 
that  the  male  semen  alone  furnished  all  the 
vital  parts  of  the  new  animal,  the  female 
organs  merely  affording  the  offspring  a  fit  place 
and  suitable   materials  for  its  nourishment. 

*  See  Blumenbach  uber  den  Bildungstrieb,12mo. 
Gotting.  1791.  Anglice  by  A.  Crichton  :  An  Essay 
on  Generation,  12mo.  Lond.  1792. 


Immediately  upon  the  discovery  of  the  seminal 
animalcules,  these  minute  moving  particles 
were  regarded  by  some  as  the  rudiments  of  the 
new  animal.  They  were  said  to  be  miniature 
representations  of  men,  and  were  styled  ho- 
munculi,  one  author  going  so  far  as  to  delineate 
in  the  seminal  animalcule  the  body,  limbs, 
features,  and  all  the  parts  of  the  grown  human 
body.  The  microscopic  animalcules  were  held 
by  others  to  be  of  different  sexes,  to  copulate, 
and  thus  to  engender  male  and  female  off- 
spring; and  the  celebrated  Leeuwenhoek,  who 
was  among  the  first  to  observe  these  animal- 
cules, described  minutely  the  manner  in  which 
they  gained  the  interior  of  the  egg,  and  held 
that  after  their  entrance  they  were  retained 
there  by  a  valvular  apparatus. 

The  theory  of  Syngenesis  or  Combination 
seems  to  have  been  applied  principally  to  the 
explanation  of  reproduction  of  quadrupeds  and 
man,  the  existence  and  nature  of  the  ova  of  which 
were  involved  in  doubt.  This  hypothesis  con- 
sists in  the  supposition  that  male  and  female 
parents  both  furnish  simultaneously  some  semen 
or  product ;  that  these  products,  after  sexual 
union,  combine  with  one  another  in  the  uterus, 
and  thus  give  rise  to  the  egg  or  structure  from 
which  the  foetus  is  formed.  In  connexion  with 
this  theory  we  may  also  mention  that  of  Meta- 
morphosis, according  to  which  a  formative 
substance  is  held  to  exist,  but  is  allowed  to 
change  its  form  in  order  to  be  converted  into 
the  new  being ;  as  also  the  notion  of  Buffon 
that  organic  molecules  universally  pervade 
plants  and  animals,  that  these  are  all  endowed 
with  productive  powers,  that  a  certain  number 
are  employed  in  the  construction  of  the  textures 
of  organized  bodies,  and  that  in  the  process  of 
generation  the  superabundant  quantity  of  them 
proceeds  to  the  sexual  organs  and  there  consti- 
tutes the  rudiments  of  the  offspring. 

The  theories  of  generation  proposed  before 
the  commencement  of  the  seventeenth  century 
are  either  unsatisfactory  or  erroneous  from  the 
entire  want  of  accurate  knowledge  prevailing 
before  that  time  regarding  the  relation  of  the 
egg  to  reproduction.  The  conversion  of  one 
animal  into  another,  constituting  equivocal  or 
spontaneous  generations,  was  very  generally 
believed  in  ;  and  the  process  of  the  formation 
of  the  egcr  was  equally  ill  understood  in  the 
lower  and  higher  classes  of  animals.  It  was  in 
the  course  of  the  seventeenth  century  that  the 
labours,  first  of  Harvey,  and  afterwards  of 
Swammerdam,  Redi,  Malpighi,  De  Graaf,  and 
Vallisneri,  gave  rise  to  greater  precision  of 
knowledge  and  opinions  regarding  this  subject, 
and  finally  established  the  Harveyan  dictum, 
"  omne  vivum  ex  ovo,"  which  may  be  regarded 
as  the  starting  -  point  or  basis  of  modern 
researches. 

The  theories  of  generation  seem  after  the 
period  of  Harvey  to  have  changed  somewhat 
their  object,  and  to  have  been  directed  more 
exclusively  to  the  explanation  of  the  formative 
process,  or  the  manner  in  which  the  parts  of 
the  foetus  are  first  formed  in  the  egg  and  after- 
wards attain  their  ultimate  structure  and  con- 
figuration. 

2  f  2 


428 


GENERATION. 


It  was  then  that  the  foundation  was  laid  for 
the  discussion  between  Epigenesis  and  Evolu- 
tion, the  two  theories  of  generation  which  have 
more  recently  occupied  the  attention  of  men 
of  science,  and  which,  as  has  already  been 
remarked,  relate  principally  to  the  nature  of 
the  formative  process.  Harvey  and  Malpighi 
may  be  regarded  as  the  first  who  endea- 
voured, from  the  observation  of  facts,  to 
establish  the  general  law  of  Epigenesis  as 
opposed  to  the  older  views  of  Preformation 
entertained  by  the  Ovists  or  Spermatists ;  but 
it  was  not  till  near  the  middle  of  the  last 
century  that  these  opinions  were  opposed  to  one 
another  in  a  decidedly  controversial  manner. 

At  that  time  Caspar  Frederick  Wolff*  sup- 
ported the  system  of  Epigenesis  by  a  reference 
to  observations  on  the  minute  changes  of  the 
egg  of  the  fowl  during  the  early  stages  of 
formation  of  the  chick,  while  Haller  and  Bonnet 
advocated  the  opposite  opinion  of  Evolution. 

Wolff  and  those  who  followed  his  system 
held  that  no  appearance  of  the  new  animal  is 
to  be  found  in  the  perfect  impregnated  egg 
before  the  commencement  of  incubation,  but 
that  when  the  formative  process  is  established 
by  the  influence  of  heat,  air,  and  other  circum- 
stances necessary  to  induce  it,  the  parts  of  the 
foetus  are  gradually  put  together  or  built  up  by 
the  apposition  of  their  constituent  molecules. 
Hallerf  referred  both  to  his  own  observations 
on  the  chick  and  to  a  variety  of  collateral 
arguments  in  support  of  the  system  of  Evolu- 
tion, holding  that  when  the  foetus  makes  its 
appearance  in  the  egg,  it  does  so  merely  in 
consequence  of  the  enlargement  or  evolution 
of  its  parts  which  pre-exist,  though  in  an 
invisible  condition,  in  the  egg.  Bonnet}  carried 
this  theory  further  than  any  one  else,  but 
trusting  mainly  to  the  observations  of  Haller 
on  the  formation  of  the  foetus,  he  supported  his 
overdrawn  views  on  highly  hypothetical  reason- 
ing. Bonnet,  in  what  is  termed  the  theory  of 
Emboitement,  held  not  only  that  the  whole  of 
the  parts  of  the  foetus  pre-exist  in  the  egg 
before  the  time  of  their  appearance,  but  also 
that  the  germs  of  all  the  animals  which  have 
been  or  are  to  be  born  pre-exist  from  the  begin- 
ning in  the  ovaries  of  the  female ;  that  the 
genital  organs  of  the  first  parents  of  any  species, 
therefore,  contain  the  germs  of  all  their  pos- 
terity ;  that  these  germs  lie  dormant  in  their 
abode  until  one  or  more  are  aroused  by  the 
exciting  influence  of  the  male;  and  that  con- 
sequently there  is  not  in  nature  the  new  forma- 
tion of  any  animal. 

We  shall  have  occasion  to  shew  in  the  article 
Ovum  that  the  most  recent  researches  concern- 
ing the  mode  of  formation  of  the  foetus  in 
birds,  quadrupeds,  and  other  animals,  and 
more  particularly  the  microscopic  observations 

*  Theoria  Generationis,  published  as  an  Inaugu- 
ral Dissertation  at  Berlin  in  1759,  and  republished 
jn  8vo.  in  1774. 

t  Elementa  Physiologiae,  &c.  torn.  vii.  Mem. 
sur  la  formation  du  Cceur  dans  le  Poulet.  Lau- 
sanne, 1758,    Opera  Minora,  torn.  ii. 

f  Palingenesie  Philosophique,  Geneve,  1769 ; 
also  in  his  Considerations  sur  les  Corps  Organises. 


of  Meckel,  Pander,  Baer,  and  Rathke,*  have 
shewn  the  theory  of  Epigenesis  or  super- 
formation  of  parts  to  be  much  more  consistent 
with  what  is  known  from  observation  than  the 
theory  of  Evolution.  In  modern  writings, 
however,  the  term  Development  is,  without 
reference  to  theory,  employed  to  denote  the 
mode  of  growth  of  the  foetus  more  frequently 
than  any  other. 

We  would  further  remark  in  relation  to  our 
present  subject  that  various  names  have  at 
different  times  been  given  by  authors  gene- 
ralizing the  phenomena  of  development  to  the 
powers  supposed  to  operate  in  the  formation  of 
the  young ;  as,  for  example,  the  Anima  vege- 
taliva,  Nisus  J'ormativus,  Vis  plastica,  Vis 
essentialis,  expansive,  resisting,  and  vegeta- 
tive forces.  These  terms  can  be  considered 
as  little  else  than  general  expressions  of  the 
fact  that  the  foetus  is  formed  and  grows  in  the 
egg,  and  are  not  more  satisfactory  expla- 
nations of  the  cause  of  its  formation  than  the 
hypothesis  of  organic  affinity  is  of  the  process 
of  assimilation  in  the  adult  animal.  As  the 
knowledge  of  minute  anatomy  and  physiology 
has  increased,  and  the  accurate  observation  of 
the  process  of  developement  has  been  more 
extended,  the  number  of  such  hypotheses  has 
gradually  diminished. 

Thus  the  somewhat  vague  discussion  as  to 
the  relative  probability  of  Epigenesis  and  Evo- 
lution has  led  to  the  laborious  and  accurate 
investigation  of  the  various  steps  of  the  forma- 
tive process  or  developement  of  the  foetus,  and 
the  conjectures  as  to  the  forces  or  causes  which 
give  rise  to  the  growth  of  the  new  animal  have 
fallen  into  comparative  neglect;  the  erroneous 
notions  respecting  the  source  of  the  germs  of 
male  or  female  offsprings  from  one  or  other 
ovary  or  testicle  have  been  replaced  by  a  more 
satisfactory  examination  of  the  mode  of  deve- 
lopment of  the  sexual  organs  in  the  early  stages 
of  their  advancement;  and  the  inquiry  as  to 
the  share  taken  by  one  or  other  parent  in  the 
process  of  generation  has  been  pursued  in  more 
modern  times  by  the  attentive  investigation  of 
the  functions  of  the  male  and  female  organs  of 
reproduction,  upon  the  same  principles  that 
guide  the  physiologist  in  his  attempts  to  explain 
any  other  class  of  functions  of  the  economy. 

Recent  writings  on  our  subject  are  not,  how- 
ever, altogether  free  from  vague  hypotheses  of 
the  same  nature  as  the  older  theories  of  gene- 
ration above  mentioned.  The  mechanical 
explanation  of  fecundation  by  the  entrance  of 
the  seminal  animalcule  into  the  egg  has  been 
revived  by  one  author;  a  second  considers 
all  the  changes  of  development  as  under  the 
influence  of  electro-magnetic  currents  ;  and  a 
third  explains  the  same  changes  by  attributing 
them  to  a  spontaneous  motive  power  and 
organic  affinitive  properties  of  the  molecules 
of  the  ovum. 

It  has  been  well  remarked  by  Professor 

*  After  these  observers  may  be  mentioned  Serres, 
Prevost  and  Dumas,  Dutrochet,  Rolando,  Purkinje 
and  Valentin,  Coste,  and  otheis,  as  contributing 
materially  to  the  knowledge  of  this  subject. 


GENERATION. 


429 


Burdach  that  the  generative  function,  com- 
prising the  production  of  a  fruitful  egg  and  the 
formation  of  the  young  animal  from  it,  are 
natural  phenomena  not  more  secret  in  their 
essence  than  others  occurring  in  organized 
bodies,  and  which,  therefore,  ought  to  be 
investigated  by  obtaining  a  knowledge  of  the 
conditions  in  which  they  take  place,  and  of  the 
operations  and  changes  in  which  they  consist. 

The  illustrious  Harvey  in  his  51st  Exercita- 
tion  expresses  himself  thus  decidedly  a  sup- 
porter of  the  theory  of  Epigenesis, — "  it  is 
plain  that  the  chicken  is  built  up  by  Epigenesis 
or  the  additament  of  parts  budding  one  out  of 
another;"  but  he  does  not  admit  that  separate 
powers,  such  as  the  "alterative  or  immutative, 
formative,  attractive,  retentive,  digestive,  and 
expulsive  faculties,   or  those  of  apposition, 
agglutination,  and  assimilative  nutrition  de- 
scribed by  Fabricius,"  can  be  distinguished  in 
the  production  of  the  chicken.    He  thus  limits 
our  knowledge  of  the  subject  in   the  54th 
Exercitation  :    "  But  as  in  the  greater  world 
we  say  Jovis  omnia  plena,  all  things  are  full  of 
the  Deity,  so  also  in  the  little  edifice  of  a 
chicken,  and  all  its  actions  and  operations, 
digitus  Dei,  the  finger  of  God  or  the  God  of 
nature  doth  reveale  himself."    "  A  more  sub- 
lime and  diviner  artificer  (than  Man  is)  seems 
to  make  and  preserve  man  ;  and  a  nobler  agent 
than  a  cock  doth  produce  a  Chicken  out  of  the 
egge.    For  we  acknowledge  our  omnipotent 
God  and  most  high  Creator  to  be  every  where 
present  in  the  structure  of  all  creatures  living, 
and  to  point  himself  out  by  his  workes  ;  whose 
instruments  the  cock  and  hen  are  in  the  gene- 
ration of  the  chicken.    For  it  is  most  apparent, 
that  in  the  generation  of  the  chicken  out  of  the 
egge,  all  things  are  set  up  and  formed,  with  a 
most  singular  providence,  divine  wisdom,  and 
an  admirable  and  incomprehensible  artifice." 
"  Nor  can  these  attributes  appertain  to  any  but 
to  the  Omnipotent  Maker  of  all  things,  under 
what  name  soever  we  cloud  him  ;  whether  it 
be  the  mem  divina,   the  divine  mind  with 
Aristotle,  or  anima  mundi,  the  soul  of  the 
universe  with  Plato;  or  with  others  natura 
nuturans,  Nature  of  nature  herself;  or  else 
Saturnus  or  Jupiter  with  the  heathen,  or  rather 
as  befits  us,  the  Creatour  and  Father  of  all 
things  in  heaven  and  earth  ;  upon  whom  all 
animals  and  their  births  depend:  and  at  whose 
beck  or  mandat,  all  things  are  created  and 
begotten."* 

3.  Spontaneous  generation  of  animals. — In 
this  introductory  view  of  the  function  of  gene- 
ration, it  may  be  proper  shortly  to  inquire 
whether  a  regular  affiliation  from  parent  to 
offspring  be  an  indispensable  condition  for  the 
continuation  of  the  species  of  every  kind  of 
animal, — a  question  somewhat  speculative  in 
its  nature,  but  of  considerable  interest  in  rela- 
tion to  some  of  the  general  doctrines  of  physio- 
logy, as  well  as  closely  connected  with  our 
present  subject.    It  has  already  been  stated  in 

*  Anatomical  Exercitations  concerning  the  Ge- 
neration of  Living  Creatures.  London,  1653, 
p.  310  ct  seq. 


general  terms  that  origin  by  generation  and  the 
power  of  reproduction  are  characteristics  be- 
longing to  all  organized  bodies  whether  of  the 
vegetable  or  animal  kingdoms.  The  existence 
of  life  implies  the  sequence  of  decay  and  death, 
or  m  other  words,  those  varied  operations  and 
changes  which  together  constitute  the  living 
state  continue  to  occur  in  each  organized  body 
for  a  limited  period  only  :  they  sooner  or  later 
undergo  a  gradual  alteration,  are  less  regularly 
performed,  and  ultimately  entirely  cease  in 
death.  But  although  every  individual  belong- 
ing to  the  organized  kingdom  of  nature  is 
necessarily  subject  to  death,  the  species  of  each 
plant  and  animal  never  becomes  extinct,  but 
is  continued  upon  earth  in  an  undeviating  suc- 
cession of  generations.  The  origin  of.a  mineral, 
on  the  other  hand,  is  wholly  independent  of 
any  pre-existing  body  of  its  own  kind ;  and, 
in  the  mineral  kingdom,  all  those  bodies  are 
held  to  belong  to  the  same  species  which  agree 
in  external  form,  physical  properties,  and 
chemical  constitution.  The  mineral  owes  its 
first  origin,  as  its  subsequent  increase,  to  the 
simple  union  of  its  component  particles ;  but 
the  successive  generations  of  every  species  of 
organized  bodies  constitute  an  uninterrupted 
chain  extending  from  the  time  of  their  first 
creation,  and  in  which  the  formation  of  every 
new  link  that  is  added  depends  on  its  tem- 
porary attachment  to  that  which  preceded  it. 
So  fixed,  indeed,  is  the  law  of  continued 
reproduction  of  organized  bodies,  that  many 
naturalists  have,  in  the  absence  of  more  definite 
distinctive  characters,  adopted  the  circumstance 
of  reproduction  as  the  only  certain  means  of 
determining  what  individuals  ought  to  be 
regarded  as  belonging  to  one  species. 

While  most  naturalists  readily  admit  the 
correctness  of  the  above-mentioned  general 
law,  some  are  inclined  to  hold  that  it  is  not 
universally  applicable,  and  that  there  are  excep- 
tions to  it  both  in  the  vegetable  and  animal 
kingdoms  of  organized  nature.  It  is  among 
the  simplest  kinds  of  plants  and  animals  that 
these  exceptions  are  conceived  to  exist,  and 
more  particularly  among  cryptogamic  plants 
of  the  nature  of  mould,  small  microscopic 
animalcules  formed  in  infusions  of  decaying 
organic  matters,  and  the  Entozoa  which  live  in 
the  bodies  of  other  animals.  These  living 
productions  are  supposed  by  some  to  arise  in- 
dependently of  others  of  the  same  kind,  nearly 
in  the  manner  of  minerals,  by  the  aggregation 
of  their  component  molecules,  with  this  diffe- 
rence, that  these  molecules  are  of  an  organic 
kind.  This  sort  of  production  without  parents 
has  been  termed  Spontaneous  Generation.  It 
has  also  received  at  different  times  various 
other  appellations,  such  as  equivocal,  doubtful, 
primitive,  original,  and  heterogeneous  gene- 
ration. 

At  one  time  it  was  a  common  belief  among 
scientific  men  as  well  as  the  vulgar  that 
many  animals  might  be  produced  by  sponta- 
neous generation,  as  for  example,  the  numerous 
insects  or  their  larvae  infesting  putrid  sub- 
stances, various  kinds  of  worms  (Annelida), 
and  Molluscous   animals,   as   well  as  even 


430 


GENERATION. 


some  fishes  and  reptiles ;  but  the  increased 
knowledge  of  the  structure  and  habits  of  these 
animals,  and  in  particular  the  observations  of 
Redi*  and  others,  demonstrated  the  error  of 
this  opinion,  and  shewed  it  to  have  arisen 
merely  from  the  circumstance  of  their  real 
mode  of  generation  not  having  been  observed. 
After  this  many  felt  inclined  to  reject  entirely 
the  occurrence  of  spontaneous  generation  in 
any  class  of  organized  beings,  and  at  the  present 
day  the  question  cannot  be  regarded  as  by  any 
means  entirely  set  at  rest.  From  the  nature 
of  the  observations  and  experiments  required  in 
an  investigation  of  this  nature,  there  is  almost 
an  impossibility  of  arriving  at  a  perfectly  satis- 
factory conclusion ;  but  so  far  as  the  facts  at 
present  entitle  us  to  form  an  opinion,  it  may  be 
stated  that  spontaneous  generation,  if  it  occurs, 
takes  place  in  the  simplest  kinds  of  organized 
beings  only ;  that  in  most  of  them  it  is  only 
occasional ;  and  that  therefore  this  form  of  ge- 
neration is  to  be  looked  upon  as  a  rare  excep- 
tion to  the  usual  and  almost  universal  mode  of 
reproduction  by  the  separation  of  a  living  por- 
tion from  a  parent  body. 

Minute  animalcules,  the  greater  number  of 
which  are  so  small  as  to  be  visible  only  with 
the  microscope,  are  formed  in  the  infusions  of 
almost  all  kinds  of  organic  matter,  such  as 
starch,  sugar,  gum,  seeds,  and  different  animal 
substances,  when  these  infusions  enter  into  pu- 
trefaction. The  kinds  of  these  animalcules  are 
very  numerous,  and  the  circumstances  which 
seem  to  determine  the  formation  of  one  or  other 
sort  are  infinitely  varied.  Thus  the  nature  of 
the  substance  suspended  in  the  infusion;  and, 
in  the  same  infusions,  the  degree  of  heat,  the 
extent  of  the  decomposition,  the  quantity  and 
nature  of  the  air  admitted,  the  rapidity  with 
which  it  is  renewed,  and  the  strength  of  the  in- 
fusion or  the  relative  proportion  of  water  and 
organic  matter  in  it,  all  appear  to  exert  a  certain 
inlluence  in  determining  the  formation  of  one 
or  other  of  the  kinds  of  animalcule. 

Two  suppositions  may  be  entertained  regard- 
ing the  first  origin  of  Infusoria ;  the  one,  that 
of  their  spontaneous  generation  ;  the  other,  that 
of  their  developement  or  evolution  from  some 
pre-existing  egg  or  germ.  Those  who  disbe- 
lieve in  the  first  and  adopt  the  second  hypo- 
thesis hold  that  the  ova  of  the  animalcules  exist 
in  the  substances  of  the  infusions,  or  are  float- 
ing every  where  in  the  atmospheric  air ;  that 
these  ova  become  developed  in  that  species  of 
infusion  only  which  is  suited  to  serve  as 
their  proper  nidus  or  matrix;  and  that  all  the 
varieties  of  animalculse  in  different  infusions 
depend  upon  the  infusions  being  suited,  from 
their  composition  or  the  external  agencies  to 
which  they  are  subjected,  to  cause  the  develop- 
ment of  different  sorts  of  ova.  The  supporters 
of  the  hypothesis  of  Spontaneous  Generation 
hold,  on  the  other  hand,  that  certain  changes 
of  composition  of  the  organic  molecules  in  the 
infusions,  in  whatever  way  induced,  are  the  sole 
cause  of  the  formation  of  one  or  other  kind  of 
ainrnalcule. 

*  De  Geaeratione  Insectorum.    Amst.  1686. 


Spallanzani,*  one  of  the  most  strenuous  op- 
ponents of  the  hypothesis  of  spontaneous  gene- 
ration, shewed  by  very  accurate  experiments 
that  no  animalcules  are  formed  when  the  access 
of  air  to  the  infusion  is  completely  prevented,  as 
for  example,  when  it  is  covered  with  a  little  oil,  or 
the  vessel  containing  it  is  closely  sealed  ;  and 
he  thence  concluded  that  the  germs  of  the  ani- 
malcules must  exist  in  the  atmosphere;  but  the 
supporters  of  the  hypothesis  consider  them- 
selves as  entitled  to  hold  that  no  production  of 
animalcules  takes  place  in  these  circumstances, 
merely  because  the  exclusion  of  the  air  has  the 
effect  of  preventing  that  species  of  decomposi- 
tion which  they  regard  as  necessary  for  the 
formation  of  the  Infusoria. 

It  is  stated  by  some  experimenters  that  ani- 
malcules are  produced  when  the  infusions  are 
exposed  to  hydrogen  and  nitrogen  gases,  or  to 
atmospheric  air  artificially  prepared  ;  in  which 
it  is  held  that  there  can  be  no  living  ova  of 
animalcules.  Again,  it  appears  from  numerous 
experiments,  that  when  the  infusions  have  been 
exposed  to  a  boiling  temperature,  which  is  ge- 
nerally believed  to  have  the  effect  of  destroying 
the  life  of  all  organized  productions,  the  quan- 
tity of  animalcules  formed  is  not  diminished. 
Some  air,  it  has  already  been  stated,  must  always 
be  present ;  but  so  far  as  we  are  aware,  the  ex- 
periments on  this  point  have  not  been  per- 
formed in  such  a  manner  as  to  ascertain,  whe- 
ther or  not,  when  an  infusion  is  allowed  to  come 
in  contact  with  a  considerable  portion  of  con- 
fined air,  and  the  whole  apparatus  is  exposed 
to  a  temperature  above  that  of  boiling  water, 
the  production  of  Infusoria  may  still  take  place; 
and  we  are  consequently  obliged,  in  the  absence 
of  more  direct  experiment,  to  have  recourse  to 
analogical  reasoning. 

The  following  considerations  appear  to  us  to 
throw  the  balance  of  evidence  in  favour  of  the 
spontaneous  production  of  Infusoria,  mould, 
and  the  like. 

Firstly,  those  organic  matters  which  are  most 
soluble  in  water,  and  at  the  same  time  most 
prone  to  decomposition,  give  rise  to  the  greatest 
quantity  of  animalcules  or  cryptogamic  plants. 

Secondly,  the  nature  of  the  animalcule  or 
vegetable  production  bears  a  constant  relation 
to  the  state  of  the  infusion,  so  that,  in  similar 
circumstances,  the  same  are  always  produced 
without  this  being  influenced  by  the  atmo- 
sphere. There  seems  also  to  be  a  certain  pro- 
gressive advance  in  the  productive  powers  of 
the  infusion,  for  at  the  first  the  animalcules  are 
only  of  the  smallest  kinds  or  Monades,  and  after- 
wards they  become  gradually  larger  and  more 
complicated  in  their  structure;  after  a  time  the 
production  ceases,  although  the  materials  are 
by  no  means  exhausted.  When  the  quantity 
of  water  is  very  small  and  the  organic  matter 
abundant,  the  production  is  usually  of  a  vege- 
table nature;  when  there  is  much  water,animal- 
cules  are  more  frequently  produced. 

Thirdly,  on  the  supposition  that  infusory  ani- 
malcules are  developed  from  ova,  it  is  neces- 

*  Tracts  on  the  Nature  of  Animals  and  Vegeta- 
bles.   Edin.  1799,  (transl.) 


GENERATION. 


431 


sary  to  conclude,  from  the  experiments  already 
referred  to,  that  these  ova  are  in  some  instances 
derived  from  the  atmosphere,  but  yet  the  num- 
ber of  Infusoria  is  by  no  means  in  direct  pro- 
portion with  the  quantity  of  air.  We  are  also 
reduced  to  the  necessity  of  holding  that  every 
portion  of  the  atmospheric  air  is  equally  im- 
pregnated with  infusorial  germs  or  ova,  and 
that  these  bodies  may  remain  for  years  dis- 
solved, as  it  were,  or  invisibly  suspended  in  the 
atmosphere,  and  in  a  perfectly  dry  state — a 
supposition  contrary  to  analogy,  and  not  fully 
warranted  by  the  fact  that  Vibriones  may  be 
resuscitated  by  means  of  moisture  after  they 
have  been  kept  in  a  dry  state  for  long  periods. 

Fourthly,  it  may  be  remarked  that  the  exist- 
ence of  ova,  as  belonging  to  many  of  the  Infu- 
soria, is  entirely  hypothetical,  since  most  of 
these  animals  are  known,  when  once  formed,  to 
propagate  by  other  means,  as  by  the  division  of 
their  whole  bodies  or  by  budding. 

The  production  of  infusorial  animalcules 
from  solutions  of  granite,  silex,  &c.  recently 
described  by  Mr.  Crosse,  we  have  no  hesitation 
in  pronouncing  to  be  either  a  mistake,  or  the 
result  of  changes  occurring  in  admixed  particles 
of  organic  matter. 

The  Entozoa,  or  that  class  of  animals  which 
live  only  in  the  bodies  of  others,  afford  proofs 
of  spontaneous  generation  still  more  convincing 
than  those  already  mentioned.  These  remark- 
able animal  productions  are  capable  of  existing 
no  where  but  in  the  bodies  of  those  animals 
which  they  naturally  inhabit :  they  live  either 
loose  or  attached,  within  cavities  or  imbedded 
in  the  substance  of  the  textures;  sometimes  in 
places,  such  as  the  alimentary  canal  or  respira- 
tory passages,  to  which  the  external  air  has 
access,  and  at  other  times  in  close  cavities  of 
the  body,  into  which  there  is  no  opening  from 
without,  such  as  the  chambers  of  the  eye,  the 
serous  sacs,  cysts,  and  other  cavities,  in  the 
parenchyma  of  organs,  the  bloodvessels,  &c. 
Entozoa  do  not  live  for  any  length  of  time  after 
being  discharged  from  the  natural  places  of 
their  abode  ;  and  they  survive  a  very  short  time 
only  after  the  death  of  the  animals  in  which 
they  live. 

If  Entozoa  are  not  admitted  to  be  the  pro- 
duct of  spontaneous  generation,  in  order  to  ac- 
count for  their  origin,  it  becomes  necessary  to 
suppose  either  that  these  creatures  themselves 
or  their  ova  pass  directly  from  one  animal  to 
another,  or  that  they  are  introduced  through  the 
medium  of  air  or  water.  Upon  the  first  sup- 
position, carnivorous  animals  ought  to  be 
affected  with  entozoa,  at  least  in  greatest  quan- 
tity, if  not  in  some  instances  exclusively  ;  and 
the  entozoa  infesting  any  particular  animal 
ought  to  be  of  the  same  kind  as  those  which 
exist  in  the  animal  serving  it  for  food.  But 
such  is  by  no  means  the  case.  Herbivorous  as 
well  as  carnivorous  animals  have  entozoa,  and 
in  no  less  quantity,  and  each  animal  is  the 
abode  of  its  own-peculiar  kind.  The  same  en- 
tozoa infest  the  same  animals  in  all  localities 
and  climates;  thus  all  the  human  entozoa,  with 
the  exception  of  the  Dracunculus  or  Guinea- 
worm,  which   is  an  external  parasite  rather 


than  a  true  entozoon,  are  the  same  in  all  races 
of  men.  Neither  do  we  recognise  any  simi- 
larity between  the  entozoa  infesting  animals  of 
a  particular  district  and  allied  tribes  of  animals 
living  in  the  neighbouring  waters 

In  adopting  the  second  supposition  that  the 
eggs  or  germs  of  Entozoa  may  gain  the  bodies 
of  animals  by  circuitous  routes,  we  are  met  by 
many  difficulties  in  addition  to  those  already 
stated  in  reference  to  a  similar  explanation  of 
the  origin  of  Infusoria.  Many  Entozoa  reside 
only  in  particular  organs  of  the  body,  and  in 
the  very  interior  of  these  organs,  as  the  human 
Cysticercus  cellulosus  in  the  choroid  plexus  of 
the  brain,  in  the  substance  of  the  brain  itself, 
in  the  chambers  of  the  eye,  &.c.  so  that  it  is 
necessary  to  suppose  the  ova  of  Entozoa  to  have 
been  introduced  into  the  circulation,  carried 
through  the  smallest  bloodvessels,  and  depo- 
sited in  the  places  in  which  they  are  developed. 
Animals  living  in  the  same  situations  and  feed- 
ing on  the  same  substances  have  different  kinds 
of  Entozoa.  The  ova  of  some  of  the  Entozoa, 
as  for  example,  those  of  the  common  round 
worm,  (Ascaris  lumbricoides,)  are  so  large  that 
they  could  not  pass  through  the  largest  even  of 
the  capillary  bloodvessels  :  the  ova  are  so  heavy 
that  they  could  not  be  transmitted  through  the 
atmosphere  ;  and  the  supposition  of  the  passage 
of  the  ova  from  parent  to  offspring  is  opposed 
by  the  mechanical  difficulty  of  the  transmission, 
as  well  as  by  the  facts  that  parent  and  child 
are  not  always  affected  with  the  same  kinds  of 
worms,  and  that  though  the  complaint  of  worms 
may  be  said  to  run  in  families,  yet  many  escape, 
and  one  or  more  generations  in  the  hereditary 
succession  are  frequently  exempt  from  it.  En- 
tozoa have  been  observed  in  the  foetus  of  ani- 
mals, and  supposing  them  to  be  introduced  from 
without,  it  would  be  necessary  to  hold  that  the 
entozoa  themselves  or  their  ova  have  passed 
directly  from  the  mother  to  the  child  in  the 
uterus,  or  to  have  traversed  a  route  through 
which  the  globules  of  the  blood  are  not  trans- 
mitted. 

Some  of  the  Entozoa,  we  may  further  remark, 
when  once  formed,  are  viviparous  or  bear  their 
young  alive;  and  with  regard  to  these  kinds  it 
would  be  necessary  to  suppose  that  they  may 
arise  by  invisible  ova  or  germs  as  well  as  pro- 
pagate in  the  viviparous  mode. 

These  facts  appear  to  us  to  speak  strongly  in 
favour  of  the  occasional  occurrence  of  sponta- 
neous generation, — "  a  doctrine  which,  had  it 
not  been  applied  in  many  instances  where  it 
was  manifestly  untrue,  would  have  met  with 
less  ridicule  and  a  more  just  appreciation  than 
it  has  usually  obtained."  The  epithet  "  spon- 
taneous," which  we  have  retained  as  the  most 
common,  is  equally  inappropriate  as  applied  to 
this  or  to  any  other  of  the  processes  of  nature  ; 
and  the  analogy  of  by  far  the  greater  number  of 
plants  and  animals  militates  against  the  proba- 
bility of  the  hypothesis  ;  but  it  must  at  the 
same  time  be  held  in  mind  that  the  organized 
bodies  in  which  spontaneous  production  has 
been  said  to  occur  differ  widely  in  their  general 
structure  and  functions  from  those  which  are 
reproduced  by  means  of  ova ;  and  we  are 


432 


GENERATION. 


scarcely  entitled  to  reject  the  hypothesis  of  their 
spontaneous  generation,  merely  on  the  ground 
that,  in  this  respect,  they  do  not  agree  with  the 
rest  of  the  animal  kingdom.  Uarvey  even, 
who  established  the  proposition  omne  vivum  ex 
ovo,  seems  yet  to  have  acknowledged  the  ne- 
cessity of  admitting  some  difference  between 
the  more  ordinary  form  of  generation  by  means 
of  an  egg  and  that  which  he  called  of  the  spon- 
taneous kind.* 

In  conclusion,  we  may  remark,  that  while 
we  feel  inclined  to  admit  the  existence  of  spon- 
taneous generation  among  some  species  of  cryp- 
togamic  plants,  infusorial  animalcules,  and  en- 
tozoa,  it  must  be  held  in  recollection  that  many 
of  these  productions,  after  their  first  origin, 
propagate  their  species  as  parents, — that  the  so- 
called  spontaneous  kind  of  generation  is  to  be 
looked  upon  as  no  more  than  an  exception  to 
the  general  law  of  reproduction,  —  and  that 
therefore  extreme  caution  is  necessary  in  admit- 
ting any  organized  body  to  be  the  product  of 
spontaneous  generation  upon  the  mere  negative 
evidence  of  the  absence  of  its  seeds  or  ova. 

II.  SKETCH  OF  THE  PRINCIPAL  FORMS  OF 
THE  REPRODUC1IVE  FUNCTION  IN  DIFFE- 
RENT ANIMALS. 

Before  proceeding  to  detail  the  different  steps 
of  Human  Generation,  which  forms  the  more 
immediate  subject  of  consideration  in  this  arti- 
cle, we  shall  endeavour  to  present  a  short  pre- 
liminary sketch  of  the  various  forms  which  the 
reproductive  function  assumes  in  different  classes 
of  animals. 

Reproduction  may  be  divided  into  non-sexual 
and  sexual,  according  as  the  whole  process  is 
accomplished  by  one  class  of  organs  in  a  single 
individual,  or  by  the  concurrence  of  two  diffe- 
rent kinds  of  organs  placed  either  upon  one  or 
upon  two  separate  individuals  of  the  same 
species ;  the  first  form  occurring  among  the 
simplest  kinds  of  animals  only,  the  second  be- 
longing to  all  the  vertebrated  and  the  higher 
classes  of  invertebrated  animals. 

1.  Non-sexual  reproduction.  —  Of  the  non- 
sexual mode  of  reproduction  three  principal 
kinds  may  be  distinguished,  viz.  first,  by  divi- 
sion ;  second,  by  attached  buds;  and  third,  by 
separated  gemma. 

Fissiparous  generation. — The  most  common 
form  of  the  fissiparous  generation,  as  the  first 
of  these  varieties  has  been  called,  is  met  with 
in  some  of  the  simpler  Infusoria;  but  it  also 
occurs  occasionally  in  animals  higher  in  the 
scale.  It  consists  essentially  in  the  division  of 
the  parent  animal  body  into  a  certain  number 
of  subordinate  masses,  each  of  which,  being 
endowed  with  independent  life,  becomes  a  new 
individual  similar  to  that  of  which  it  originally 
formed  a  part.  In  some  of  the  Infusoria  in 
which  the  process  of  subdivision  has  been  mi- 
nutely observed,  fissures  are  seen  to  form  in  the 
sides  of  the  animal  which  is  about  to  be  repro- 
duced ;  these  fissures  gradually  enlarge,  and 
meeting  widi  one  another,  completely  separate 

*  See  his  Exercitations,  as  before  quoted, 
pp.  327  and  343. 


the  parts.  In  one  kind  of  fissiparous  genera- 
tion the  parent  body  is  split  into  irregularly 
shaped  masses,  in  some  two  in  number,  in  dif- 
ferent others,  four,  six,  eight,  or  twelve,  and  in 
one,  the  Gonium  pectorale,  into  as  many  as  six- 
teen. Each  of  the  subordinate  masses,  when 
first  separated  from  its  fellow,  has  an  irregular 
shape,  from  which  it  gradually  passes  into  the 
form  and  size  of  its  parent. 

In  a  second  form  of  the  fissiparous  genera- 
tion, the  infusorial  animal  is  divided  into  two 
equal  and  symmetrical  halves ;  in  some  in- 
stances in  a  longitudinal  direction,  as  in  Bac- 
cillaria  and  some  Vorticellte  ;  in  others  in  a 
transverse  direction,  as  in  Paramcecium,  Cycli- 
dium,  and  Trichoda. 

The  propagation  of  the  Volvox  globator,  a 
remarkable  infusorial  animalcule,  may  perhaps 
be  considered  as  belonging  to  the  first  of  the 
above-mentioned  varieties  of  fissiparous  genera- 
tion.* This  animal  consists  of  an  external 
vesicle  of  a  lenticular  shape,  moving  rapidly 
through  the  water  by  means  of  cilia  in  a  whirl- 
ing manner.  Within  this  outer  vesicle  there 
are  smaller  ones  of  the  same  kind,  in  the  inte- 
rior of  each  of  which  still  smaller  ones  may  be 
distinguished  by  the  aid  of  a  high  magnifying 
lens.  The  outer  vesicle  may  be  regarded  as 
the  parent,  and  the  inclosed  vesicles  as  its 
young,  for  in  propagation  the  outer  vesicle 
bursts  and  is  torn  into  shreds,  while  the  inclosed 
ones  are  set  free,  each  of  them  to  execute  its 
independent  motions  in  the  water,  and  in  its 
turn  to  burst,  and  thus  propagate  its  like  in 
discharging  those  which  it  contains. 

A  fissiparous  kind  of  generation  is  not,  how- 
ever, confined  to  the  Infusoria,  but  occurs  also 
in  some  of  the  Cestoidea  and  Annelida.  The 
most  remarkable  example  is  met  with  in  the 
Nais  and  Nerei?.  In  the  first  of  these  genera, 
a  small  portion  separated  from  the  tail  becomes 
the  new  animal.  Before  the  actual  separation 
of  this  caudal  portion,  it  is  marked  off  from  the 
rest  by  a  notch,  and  there  are  gradually  formed 
on  its  sides  the  joints,  hairs,  and  other  indica- 
tions of  the  organs  of  the  complete  animal  in 
miniature.  The  notch  enlarges,  and  the  part  at 
last  drops  off  capable  of  independent  existence. 
In  the  Nais,  that  part  of  the  offspring  by  which 
it  is  attached  to  the  parent  becomes  the  head, 
and  in  this  way,  according  to  the  singular 
notion  of  Gruithuisen,  who  observed  this  sort 
of  reproduction  with  attention ,t  the  tail  of  a 
Nais  may  be  considered  as  gifted  with  perpe- 
tual life,  since  this  part  is  extended  into  each 
of  the  new  descendants.! 

We  may  regard  as  somewhat  analogous  to 
this  kind  of  propagation  the  multiplication  of 
individuals  by  division,  which  happens  occa- 
sionally only  or  from  accident  in  several  of  the 
lower  animals  which  are  usually  reproduced 

*  Another  view  taken  of  the  reproduction  of  the 
Volvox  globator  is,  that  the  young  are  formed  in 
the  manner  of  internal  buds. 

t  Nov.  Act.  Nat.  Curios,  torn.  xi. 

%  The  segments  of  the  infusorial  animalcule 
that  is  propagating  in  the  fissiparous  mode  are 
united  by  the  parts  which  afterwards  become  the 
tails  of  the  new  individuals. 


GENERATION. 


433 


in  another  manner.  The  most  remarkable  ex- 
amples of  this  are  met  with  in  Polypi,  Entozoa, 
and  Annelida.  When  the  Hydra  viridis  is  cut. 
through  either  longitudinally  or  transversely, 
each  segment  continues  to  live  and  grow,  and 
is  gradually  furnished  with  those  parts  of  the 
body  of  which  it  was  deprived  by  the  division. 
Thus,  when  the  polype  is  divided  across  the 
body,  the  part  with  the  head  and  tentacula  is 
gradually  furnished  with  a  body,  while  ten- 
tacula grow  on  the  elongated  extremity  of  the 
other  part.  When,  again,  the  animal  has  been 
divided  in  a  longitudinal  direction,  and  four 
tentacula  are  left  on  each  part,  the  opposite 
edges  of  each  segment  turn  round  and  unite 
so  as  to  complete  the  tube  of  the  stomach, 
and  four  additional  tentacula  are  formed  upon 
each. 

Segments  of  the  Tape-worm,  Filaria,  and 
also  of  some  other  Entozoa,  are  capable  of 
living  after  separation  and  being  converted  in- 
to independent  animals.  In  the  Leech  and 
Earth-worm,  as  well  as  some  other  Annelida, 
the  division  of  the  body  into  two  or  more  seg- 
ments is  not  invariably  followed  by  death,  but 
some  or  all  of  the  portions  continue  alive,  and, 
acquiring  the  deficient  organs,  become  con- 
verted into  more  or  less  perfect  animals. 

Gemmiparous  generation. — The  second  form 
of  non-sexual  propagation  that  deserves  our 
attention  is  that  in  which  the  new  individual 
grows  upon  the  parent  as  a  bud  or  sprout,  at 
first  exhibiting  little  appearance  of  the  form  or 
structure  of  the  perfect  animal ;  gradually  as- 
suming its  form  while  still  attached  to  the 
parent  stem  ;  and  being  afterwards  separated  to 
enjoy  independent  existence. 

The  best  known  examples  of  this  kind  of 
generation  occur  in  the  polypine  and  coralline 
animals,  and  the  process  has  been  observed 
with  great  attention  by  Trembley  in  the  Hydra 
viridis.*  In  this  animal  the  young  polype 
makes  its  first  appearance  as  a  small  conical 
eminence  on  the  body  of  the  parent:  this  gra- 
dually enlarges  and  becomes  cylindrical  ;  a 
cavity  is  formed  in  its  interior,  which  at  first  is 
separate,  but  afterwards  comes  to  communicate 
with  the  stomach  of  the  parent,  so  that  aliments 
taken  by  the  parent  penetrate  into  the  stomach 
of  the  offspring.  As  the  new  polype  enlarges, 
the  internal  cavity  opens  at  the  free  extremity, 
where  a  mouth,  provided  wilh  tentacula,  is 
formed.  The  young  animal  then  catches  and 
swallows  food  for  itself:  this  food  at  first  finds 
its  way  into  the  stomach  of  the  parent,  but  after 
some  time  all  communication  between  the  two 
stomachs  is  prevented  by  the  closure  of  the  root 
of  the  stem  of  the  small  polype  ;  and  afterwards 
the  offspring  is  detached  from  the  parent,  be- 
comes a  separate  individual,  and  in  its  turn 
propagates  new  ones  from  its  sides.  The  time 
at  which  the  separation  takes  place  seems  to 
depend  in  some  measure  on  the  quantity  of 
food  within  the  reach  of  the  parent ;  this  occur- 
ring at  an  early  period  when  the  supply  is  small, 
and  when  there  may  be  supposed  to  be  a  ne- 

*  Mem.  pour  servir  a  l'Hist.  dcs  Polypes  d'eau 
douce.    Leyden,  1744. 


cessity  for  the  young  to  move  about  from  place 
to  place  in  search  of  sustenance.  Sometimes 
indeed  the  separation  is  much  retarded,  and  the 
young  ones  also  propagate  while  remaining  on 
the  parent  stem  ;  so  that  the  polype  assumes  a 
branched  form,  the  parent  stem  bearing  families 
of  several  generations. 

The  Sertularia,  Vorticella,  Zoantha  Ellisii, 
and  Cornularia  Cornucopias,  also  propagate  by 
shoots  somewhat  in  the  same  manner  as  the 
Hydra.* 

Reproduction  by  separated  buds  or  sporules. — 
The  last  form  of  the  non-sexual  reproduction  is 
that  in  which  the  young  are  formed  from  small 
detached  masses  after  they  are  separated  from 
the  body  of  the  parent.  These  bodies,  generally 
of  a  rounded  form,  may  be  regarded  as  buds 
formed  in  the  parent  body,  as  those  of  polypes 
are,  but  detached  from  it  before  the  evolution 
of  the  new  animal  begins.  They  bear  the  same 
relation  to  the  offspring  as  the  egg  of  higher 
animals  to  their  foetus  or  embryo,  and  might 
be  regarded  as  ova  but  for  an  important  dif- 
ference of  structure  to  which  we  shall  after- 
wards advert.  They  are  called  spora?,  germina 
granulosa,  and  gemma?,  or  germs  :  they  are 
homogeneous  in  their  structure,  and  the  whole 
of  the  substance  of  which  they  are  composed  is 
converted  in  the  process  of  their  development 
into  the  new  animal. 

In  some  animals  these  sporules  are  formed 
in  all  parts  of  the  body  indiscriminately,  and 
are  therefore  found  dispersed  through  it ;  in 
others  there  is  present  a  peculiar  organ  in  which 
they  are  formed,  constituting  the  simplest  form 
of  a  reproductive  organ.  The  Actinia,  Me- 
dusa?, and  some  of  the  lower  tribes  of  Mollusca 
belong  to  the  first  of  these  sets.  In  the  A.phro- 
dita  the  sporules  lie  in  the  interstices  between 
the  different  organs  of  the  animal.  In  those 
animals  in  which  a  particular  organ  is  provided 
for  the  formation  of  the  sporules,  the  name  of 
ovary  is  given  to  that  organ, — an  application  of 
the  term  not  strictly  correct,  as  it  belongs  more 
properly  to  the  organ  in  which  complete  ova  are 
produced.  The  production  of  sporules  from  a 
particular  generative  organ  is  much  the  most 
frequent  mode  of  their  formation,  and  it  ob- 
tains in  the  greater  number  of  the  lower  tribes 
of  Mollusca. 

It  is  a  fact  worthy  of  notice  that  the  spo- 
rules of  some  Zoophytes,  as  those  of  the  Sponge 
observed  by  Dr.  Grant,  are  endowed  with  a 
faculty  of  moving,  sometimes  darting  with  ra- 
pidity in  various  directions  through  the  fluids 
in  which  they  are  produced.  These  motions 
seem  to  depend  on  Cilia:  the  sporules  are  also 
provided  with  a  hook,  by  which  they  become 
attached  to  other  objects  when  they  settle, 

*  According  to  Burdach  the  propagation  of  the 
Volvox  globator,  already  mentioned,  and  of  the 
Vibrio,  Cerearia,  and  Cysticeveus,  is  effected  by  the 
formation  of  buds,  and  differs  from  that  of  the 
polype  merely  in  the  buds  being  formed  and  dis- 
charged inwardly.  We  might,  perhaps,  consider 
the  regeneration  of  lost  parts  which  takes  place  in 
some  animals  higher  in  the  scale  than  those  pro- 
pagating by  buds  as  a  manifestation  in  them  of  a 
similar  power. 


434 


GENERATION. 


preparatory  to  their  growth  and  conversion  into 
the  fixed  and  immoveable  Zoophyte. 

We  may  here  recal  to  the  recollection  of  the 
reader  that  the  different  forms  of  non-sexual 
reproduction  which  we  have  now  attempted  to 
sketch  are  not  confined  respectively  to  par- 
ticular classes  of  animals,  for  several  of  these 
animals  are  reproduced  in  more  than  one 
manner. 

The  alleged  instances  of  non-sexual  propa- 
gation occurring  in  animals  higher  in  the  scale 
than  those  already  mentioned  are  very  doubt- 
ful, and  ought  to  be  regarded  either  as  founded 
in  imperfect  knowledge  of  their  reproductive 
organs,  or  as  rare  exceptions  to  the  general  law 
of  their  propagation  by  the  sexual  mode.* 

2.  Sexual  reproduction. — The  existence  in 
animals  of  generative  organs  of  two  kinds,  and 
the  necessity  of  the  co-operation  of  both  these 
organs  in  reproduction  constitute  the  distinc- 
tion of  sex,  or  of  male  and  female.  In  sexual 
reproduction  both  kinds  of  organs  produce  a 
substance  essentially  concerned  in  the  process. 
The  product  of  the  female  organ,  or  ovarium, 
as  it  is  called,  is  the  ovum  or  egg,  a  consistent 
organised  body  of  a  regular  and  determinate 
shape,  in  which  the  new  animal  is  first  formed 
and  resides  during  its  early  growth.  A  whitish 
fluid  is  almost  always  the  product  of  the  male 
organ  or  testicle, — termed  semen,  or  the  semi- 
nal fluid,  from  a  belief  formerly  prevailing  that 
it  constituted,  like  the  seed,  the  greater  part  of 
the  new  being. 

Nature  of  the  ovum. — The  egg  is  naturally 
produced  by  the  female  without  the  concur- 
rence of  the  male,  that  is,  the  whole  substance 
is  apparently  formed  by  the  female  organ,  but 

*  In  many  of  those  instances  in  which  female 
animals  have  been  supposed  to  give  rise  to  produc- 
tive ova,  the  males  have  at  first  escaped  notice  from 
the  smallness  of  their  number  or  other  causes  ;  and 
with  regard  to  others  of  the  lower  animals,  it  may 
very  reasonably  be  doubted  whether  the  products 
called  ova  have  not  been  rather  of  the  nature  of 
gemmae  or  sporules,  such  as  those  formed  in  the 
Actinia  and  other  animals  naturally  propagating  in 
the  non-sexual  manner.  As  in  this  predicament 
may  be  mentioned,  according  to  Burdach,  Oxyuris, 
Filaria,  Ligula,  Tricuspidaria,  and  others  of  the 
Entozoa  ;  Serpula,  Sabella,  and  other  Tubicola  ; 
Cirrhopoda,  and  Mussels,  and  Scutibranchiata  and 
Cyclobranchiata.  The  Syngnathus  was  erroneously 
regarded  by  Pallas,  and  the  Perca  Marina  by 
Cavolini,  as  propagating  without  sex.  It  is,  how- 
ever, probable  that  some  animals  provided  with 
both  sexual  organs,  and  which  usually  propagate 
in  the  sexual  mode,  are  occasionally  reproduced 
without  the  immediate  concurrence  of  the  male. 
Thus  the  female  Aphis,  after  being  once  impreg- 
nated by  the  male,  bears,  for  a  certain  portion  of 
the  year,  female  young  only,  which  are  capable  of 
being  reproduced  for  nine  generations  without  any 
of  these  female  animals  receiving  any  new  influence 
from  the  male.  In  the  last  of  tliese  generations 
occurring  in  autumn,  males  also  are  produced  which 
impregnate  the  females  destined  to  carry  on  the  same 
succession  of  generations  during  the  next  season. 
According  to  some  this  extension  of  the  fecun- 
dating influence  of  the  male  through  more  than  one 
generation  is  not  confined  to  the  animals  just  men- 
tioned ;  but  without  doubt  the  instances  in  which 
this  has  been  supposed  to  be  the  case  have  been 
greatly  over-reckoned. 


the  egg  so  formed  is  incapable  of  giving  birth 
to  a  new  animal  unless  it  receive  a  certain  por- 
tion of,  or  influence  from,  the  seminal  sub- 
stance of  the  male.  This  addition  of  seminal 
fluid  to  the  egg  makes  no  immediate  percep- 
tible alteration  in  its  structure  or  appearance, 
but  awakens  in  it  the  power  of  reproduction, 
fructifies  or  fecundates  it  by  causing  a  physical 
or  vital  change,  the  essential  nature  of  which  is 
not  fully  understood. 

In  the  egg  immediately  after  its  fecundation, 
none  of  the  parts  of  the  new  animal  are 
visible.  A  certain  time  must  elapse  during 
which  the  egg  is  exposed  to  certain  favourable 
influences  of  heat,  air,  &c.  before  the  com- 
mencement of  those  changes  of  development 
and  growth  in  which  the  formative  process  of 
the  new  animal  consists.  The  great  mass  of 
the  substance  composing  the  egg  consists  of  a 
fluid,  holding  in  suspension  granules  of  animal, 
albuminous,  and  oily  matter.  The  form  of  the 
egg  is  given  by  the  external  coverings,  and 
there  is  in  every  egg  a  determinate  part  or  re- 
gion, corresponding  in  all  animals,  at  which 
the  small  rudimentary  parts  of  the  embryo  first 
make  their  appearance.  To  this  part  of  the 
egg,  which  might  be  called  its  germ,  the  power 
of  independent  life  and  reproduction  appears 
more  immediately  to  belong;  the  granular  fluid 
serves  but  to  afford  nourishment  to  the  young 
being  for  a  certain  period.  A  gemma  or  spo- 
rule,  on  the  other  hand,  is  generally  held  to 
differ  from  the  ovum  in  being  homogeneous  in 
its  structure,  having  no  investing  membranes, 
and  being  entirely  converted  into  the  substance 
of  the  new  animal  produced  from  it.  In  the 
present  state  of  our  knowledge,  however,  the 
distinction  between  an  ovum  and  a  sporule 
must  be  admitted  to  be  somewhat  arbitrary. 

The  position  of  the  male  and  female  genera- 
tive organs  upon  the  same  or  upon  different 
individuals,  and  the  place  or  manner  of  the 
development  of  the  young  animal  from  an  egg, 
are  the  two  most  prominent  circumstances  in 
regard  to  which  the  forms  of  sexual  reproduc- 
tion differ  from  one  another  in  various  animals. 
The  principal  processes  in  which  sexual  re- 
production essentially  consists,  are,  1st,  the 
formation  of  an  egg  by  the  female  organs ; 
2nd,  the  secretion  of  the  seminal  fluid  by  the 
male  organ  ;  and  3rd,  the  union  of  the  sexes, 
and  means  by  which  the  seminal  fluid  is  ap- 
plied to  the  egg  so  as  to  confer  fecundity 
upon  it. 

Hermaphrodite  generation. — In  some  of  the 
lower  tribes  of  animals  belonging  chiefly  to 
the  Annelida,  Acephala,  and  Gasteropoda,  the 
male  and  female  sexual  organs  are  placed  on 
one  individual,  an  arrangement  of  the  sexual 
organs  termed  Hermaphrodite,  and  all  the  indi- 
viduals belonging  to  one  species  are  consequently 
similarly  formed  In  Insects,  Crustacea,  some 
of  the  Mollusca,  and  all  the  Vertebrata,  the  dif- 
ferent sexual  organs  are  placed  on  two  distinct 
individuals,  which  are  thus  constituted  respec- 
tively male  and  female.  In  the  greater  number 
of  those  animals  in  which  the  last-mentioned 
arrangement  exists,  besides  the  sexual  pecu- 
liarities, there  are  in  each  certain  general  differ- 


GENERATION. 


435 


ences  in  the  structure  of  the  other  parts  of  the 
body. 

In  Hermaphrodite  animals  there  are  two 
modes  in  which  fecundation  takes  place.  In 
some  of  the  Acephala,  and  in  the  Holothuriae, 
the  union  of  the  sexual  organs  necessary  for 
fecundation  takes  place  in  a  single  individual; 
while  in  others,  as  Helix  and  Lymneus  among 
the  Gasteropoda,  copulation,  or  the  union  of 
two  individuals,  is  required,  and  there  is  mutual 
impregnation,  the  female  organ  of  each  animal 
being  fecundated  by  the  male  of  the  other, — 
a  mode  of  impregnation  which  also  exists  in 
the  common  Earth-worm,  Leech,  and  some 
other  animals.  Occasionally  we  find  that  three 
or  more  individuals  engage  in  this  sort  of  mu- 
tual fecundation,  being  arranged  in  a  chain  or 
circle.*    (See  Hermaphrodite.) 

Dioecious  reproduction,  or  with  distinct  in- 
dividuals of  different  sexes.  Oviparous  and 
viviparous  generation. — In  those  animals  again 
in  which  the  position  of  the  sexual  organs  on 
separate  individuals  renders  copulation  neces- 
sary, the  mode  of  production  of  the  new  animal 
from  the  egg  seems  to  be  the  most  prominent 
circumstance  according  to  which  the  reproduc- 
tive process  is  modified.  Thus,  while  in  a 
certain  number  of  them  the  young  are  born 
alive,  in  others  they  are  hatched  from  eggs  laid 
by  the  female  parent.  This  constitutes  the 
difference  between  Viviparous  and  Oviparous 
animals ;  to  the  first  of  which  classes  Mam- 
malia belong,  to  the  second  Birds,  and  most 
Reptiles  and  Fishes.  A  short  comparison  of 
the  more  important  steps  of  the  generative 
process  in  the  Mammiferous  animal  and  the 
Bird  will  most  readily  explain  the  difference 
between  viviparous  and  oviparous  generation. -f 

*  In  the  Cyclostoma  viviparum  the  sexes  are 
distinct. 

f  Harvey  in  the  Sixty-third  Exercitation  thus 
enforces  the  analogy  between  the  oviparous  and 
viviparous  modes  of  reproduction.  "  I  have 
already  given  you  the  reason  why  I  have  drawn 
out  documents  concerning  all  other  egges  from 
the  egges  of  Hens  ;  namely,  because  they  are 
cheap  and  every  man's  purchase." — "  But  there 
is  more  difficulty  in  the  search  into  the  gene- 
ration of  viviparous  animals  ;  for  we  are  almost 
quite  debarred  of  dissecting  the  humane  uterus  : 
and  to  make  any  inquiry  concerning  this  matter  in 
Horses,  Oxen,  Goats,  and  other  Cattel,  cannot  be 
without  a  great  deal  of  pains  and  expense  Hut 
those  who  are  desirous  to  make  tryal  whether  we 
deliver  the  truth  or  not,  may  essay  the  business  in 
Doggs,  Conies,  Cats,  and  the  like." — "  Hut  we  in 
the  entrance  of  these  our  observations  have  con- 
cluded that  all  animals  are  in  some  sort  produced 
out  of  an  egg  :  For  the  foetus  of  viviparous  creatures 
is  produced  after  the  same  manner  and  order  out  of 
a  pre-existent  conception,  as  the  chicken  is  formed 
and  constituted  out  of  an  egge.  There  being  one 
and  the  same  species  of  generation  in  them  all, 
and  the  exordium  or  first  principle  of  them  all  is 
either  called  an  egge,  or  at  lest  something  answer- 
able and  proportionable  to  it.  For  an  Egge  is  an 
exposed  conception  from  which  a  Chicken  is  pro- 
duced ;  but  a  conception  is  an  egge  retained  within, 
untill  the  foetus  have  attained  its  just  bulk  and 
magnitude  :  in  other  matters  it  squares  with  an 
egge,"  &c.  *'  Besides,  as  a  Chicken  is  hatched  out 
of  an  Egg,  by  the  fostering  heat  of  the  sitting  Hen, 
or  some  other  ascititious  hospitable  patronage,  so 
also  the  foetus  is  produced  out  of  the  conception  in 


In  both  these  classes  of  animals  ova  are 
formed  from  the  ovary,  and  in  both  the  ova 
are  fecundated  within  the  body  of  the  female 
parent.  The  process  by  which  the  egg  is  sepa- 
rated from  the  place  of  its  formation,  and  the 
changes  it  undergoes  in  being  perfected  after 
this  separation,  are  the  same  in  both  :  but  after 
the  fecundation  and  completion  of  the  egg,  it  is 
differently  placed  in  the  two  classes  of  animals ; 
for  in  birds  the  egg  passes  through  the  oviduct 
and  leaves  the  body  of  the  female  parent,  to  be 
hatched  into  life  under  the  influence  of  favour- 
able external  agents ;  while  in  the  mammiferous 
quadruped,  the  egg  remains  within  the  uterus 
of  the  female  generative  organs,  becomes  at- 
tached to  it,  and  has  there  formed  from  it  the 
young  animal,  which  does  not  quit  the  body  of 
the  parent  until  it  is  capable  of  independent 
life.  The  egg  of  the  bird  leaves  the  body  of 
the  mother  provided  with  a  considerable  quan- 
tity of  organic  matter,  by  which  alone,  under 
the  influence  of  heat  and  air,  the  embryo  is 
nourished  during  incubation.  The  egg  of  the 
mammiferous  animal  is  extremely  small  com- 
pared to  the  size  of  the  young  animal  at  birth, 
and  the  foetus  consequently  draws  a  continual 
supply  of  the  materials  of  its  nourishment  from 
the  uterus  of  the  mother,  with  which  it  is  more 
or  less  intimately  connected.  The  residence  of 
the  child  or  young  animal  in  the  body  of  the 
mother  during  its  formation  and  growth  is 
termed  pregnancy,  or  utero-gestation.* 

Ovo-vtviparous  generation. — There  are  other 
animals,  however,  besides  Mammalia,  which 
bear  their  young  alive,  as  is  the  case  in  many 
cartilaginous  and  a  few  osseous  fishes,  in 
several  Batrachia,  Sauria,  and  Ophidia,  and 
also  in  some  Gasteropodous  Mollusca,  Insects, 
Annelida,  and  Entozoa.  But  there  is  an  im- 
portant difference  to  be  pointed  out  between 
the  viviparous  form  of  generation  occurring  in 
these  animals  and  that  which  belongs  to  the 
Mammalia.  For  the  female  generative  organs 
of  the  above-mentioned  animals,  as  well  as 
the  eggs  they  produce,  resemble  much  more 
closely  in  their  structure  those  of  oviparous 
than  those  of  strictly  viviparous  animals.  As, 
in  the  animals  now  under  consideration,  the 

the  egge,  by  the  soft  and  most  natural  warmth  of 
the  parent. — "  And  then,  concerning  that  which 
relates  to  procreation,  the  fcetus  is  produced  out  of 
the  conception  in  the  selfe  same  mariner  and  order 
as  the  chicken  out  of  the  Egg  ;  with  this  only  dif- 
ference, that  in  an  egge,  whatever  relates  to  the 
constitution  and  nutrition  of  the  Chicken,  is  at  once 
contained  in  it ;  but  the  conception  (  after  the  fcetus  is 
now  formed  out  of  it) doth  attract  more  nourishment 
out  of  his  parent's  womb  ;  whereupon  the  nourish- 
ment increases  with  the  foetus." — "  The  first  Con- 
ception, or  Rudiment,  therefore,  of  all  Animals  is 
in  the  uterus,"  (this  applies  to  Quadrupeds,) 
"  which,  according  to  Aristotle,  is  like  an  egg  co- 
vered over  with  a  membrane  when  the  shell  is 
pilled  off."  And  Harvey  finally  concludes  wiih 
Aristotle  :  "All  animals,  whether  they  be  swimming, 
walking,  or  flying  animals  ;  and  whether  they  be 
born  in  the  form  of  an  Animal  or  of  an  Egg  j  ;  are 
all  generated  after  the  same  manner." 

*  The  nature  of  the  egg  of  viviparous  animals, 
which  has  only  recently  been  fully  understood, 
will  be  described  in  a  subsequent  part  of  this  paper, 
and  more  in  detail  in  the  article  UVUM. 


436 


GENERATION. 


egg  is  proportionally  large,  the  foetus  grows 
principally  by  the  assimilation  of  materials 
procured  from  it,  and  there  is  not  that  intimate 
connection  of  structure  nor  interchange  of 
substance  between  the  mother  and  foetus  which 
occurs  in  Mammalia.  The  term  ovo-viviparous 
is  applied  to  the  variety  of  reproduction  now 
under  consideration ;  as  expressing  that  in  it, 
although  the  foetus  is  produced  fully  formed 
and  alive,  the  ovum  is  merely  hatched  within 
the  parent  body.  We  find,  accordingly,  that 
this  form  of  generation  is  liable  to  vary,  and 
occasionally  to  run  into  the  truly  oviparous 
kind.  Thus,  some  animals  which  bear  live 
young  at  one  season  lay  eggs  at  another  season 
of  the  year,  as  occurs  in  some  Insects ;  and 
in  others,  as  Lacerta  agilis,  the  ova  remain 
within  the  mother's  body  for  a  part  only  of  the 
time  employed  in  the  development  of  the  young; 
the  process  of  hatching  beginning  and  going 
on  for  a  longer  or  shorter  time  within  the 
female  parent,  and  being  completed  as  in  the 
bird  without. 

In  all  truly  viviparous,  in  most  ovo-vivi- 
parous, and  also  in  many  oviparous  animals, 
the  ova  are  fecundated  within  the  parent's 
body ;  and  we  find  provided  for  the  purpose 
of  introducing  the  seminal  fluid  into  the  female 
genital  organs,  a  more  or  less  complicated  ap- 
paratus in  both  male  and  female,  by  which 
the  union  of  the  sexes  is  brought  about.  In 
the  greater  number  of  strictly  oviparous  ani- 
mals, and  particularly  those  that  are  aquatic, 
as  osseous  fishes  and  Batrachian  Reptiles, 
fecundation  is  operated  externally  to  the  pa- 
rent body;  that  is,  there  is  no  union  of  the 
sexual  organs  of  the  male  and  female,  but  the 
ova  laid  by  the  female  are  covered  with  a 
certain  quantity  of  seminal  fluid  shed  by  the 
male.* 

Utero-gestation  in  the  Mammalia  is  termi- 
nated by  parturition  or  the  birth  of  the  young; 
while  in  the  bird  or  oviparous  animal  birth  con- 
sists in  the  exclusion  of  the  young  from  the  egg. 
At  this  period  in  Mammalia,  the  organic  con- 
nection between  mother  and  offspring  is  dis- 
solved, and  in  both  viviparous  and  oviparous 
animals  the  birth  is  accompanied  by  important 
structural  changes,  which  fit  the  offspring  for 
independent  life  and  aerial  or  aquatic  respira- 
tion. The  young  of  Mammalia  after  birth, 
though  they  cease  to  be  organically  connected 
with  the  mother,  continue  to  derive  a  certain 
quantity  of  support  from  her,  feeding  on  the 
milk  secreted  by  the  mamma?.  But  in  all 
other  classes  of  animals,  the  young  are  at  birth 
capable  of  feeding  on  external  aliment. 

Varieties  in  respect  to  utero-gestution  and 
the  developement  of  the  young. — There  is  con- 
siderable variety  among  different  animals  in 
the  degree  of  perfection  at  which  the  young 
have  arrived  at  the  period  of  birth.  Thus, 
Insects,  Batrachian  Reptiles,  and  some  other 

*  In  the  land  Salamander.which  is  ovo-viviparous 
and  breeds  in  the  water  although  there  is  no  sexual 
union  of  the  male  and  female,  there  is  yet  internal 
fecundation,  the  seminal  fluid  being  carried  into 
the  oviduct  of  the  female  along  with  the  water  in 
which  it  is  effused. 


animals  leave  the  egg  at  a  very  early  period ; 
differing  widely  from  their  parents  in  struc- 
ture and  functions,  they  live  for  a  time  in  a 
masked  or  larva  condition,  and  undergo  after- 
wards various  changes  or  so-called  metamor- 
phoses before  attaining  the  mature  condition. 
Fishes  leave  the  egg  while  their  structure  is 
yet  very  incomplete;  and  even  in  the  higher 
animals  we  observe  varieties  in  this  respect: 
thus,  some  birds,  more  especially  those  build- 
ing on  trees,  are  unfledged,  blind,  and  help- 
less when  the  shell  is  broken;  and  some 
quadrupeds,  among  which  may  be  mentioned 
the  Rodentia,  Feline,  and  Canine  species, 
are  at  birth  blind  and  weak,  and  with  little 
power  of  supporting  their  natural  high  tem- 
perature.* The  most  remarkable  instance 
of  variety  of  the  kind  now  alluded  to,  how- 
ever, occurs  in  the  Kangaroo  and  other  Mar- 
supial animals,  the  generation  of  which  de- 
serves more  particular  mention  in  this  place 
as  it  exhibits  a  considerable  deviation  from  the 
more  ordinary  reproductive  process  in  Mam- 
malia, and  is  attended  with  some  important 
modifications  in  the  structure  of  the  generative 
organs. 

In  the  Mammalia  generally,  it  has  already 
been  stated  that  there  is  an  intimate  organic 
connection  between  the  foetus  and  mother,  by 
means  of  which  the  former  is  supplied  with 
the  materials  of  its  growth.  The  intimacy  of 
this  union  (as  we  shall  explain  more  fully  else- 
where) varies  much  in  different  tribes  of  ani- 
mals. It  is  greatest  in  the  placenta  of  the 
human  female,  and  from  this  there  may  be 
traced  a  series  of  animals  in  which  it  becomes 
more  and  more  loose.  According  to  recent 
researches  in  Comparative  Anatomy,  there  is 
also  observable  in  the  descending  series  of 
these  animals  a  nearer  and  nearer  approach  in 
the  general  structure  of  the  body,  and  in  the 
conformation  of  the  generative  organs  to  the 
oviparous  type.  This  approach  to  the  ovipa- 
rous structure  is  most  strongly  marked  in  the 
Marsupiata,  as  the  Opossum,  Kangaroo,  &.C. 
and  in  the  Monotremata,  as  the  Ornithorynchus 
and  Echidna.  + 

Marsupiate  generation. — The  foetus  of  the 
marsupiate  animal  leaves  the  uterine  system  of 
the  mother  or  is  born  at  an  early  period  of  its 
formation,  while  it  is  yet  of  a  very  small  size, 
and  its  organs  are  comparatively  imperfectly 
formed.  On  being  born  it  is  introduced  by 
the  mother  into  the  pouch  or  marsupium 
formed  by  a  reduplication  of  the  integuments 
of  the  lower  part  of  the  belly,  and  a  short  time 
after  it  gets  there,  the  foetus  is  found  attached 
by  its  mouth  to  one  of  the  nipples  of  the 
mamma?,  which  are  concealed  within  the  mar- 
supium.   The  young  of  the  marsupiate  animal 

*  Under  the  head  of  OVUM  we  shall  shew  that 
all  animals  undergo  changes  which  constitute  me- 
tamorphoses of  one  kind  or  other  during  their  for- 
mation or  development. 

t  See  the  interesting  papers  by  Mr.  Owen  on 
the  Generation  of  the  Kangaroo  and  Ornithoryn- 
chus in  the  Philosophical  Transactions,  part  ii. 
for  1834,  p.  333,  and  in  the  Transactions  of  the 
Zoological  Society,  vol.  i.  p.  221. 


GENERATION. 


437 


there  receives  its  food  by  the  mouth  and  is 
nourished  by  digestion  at  an  early  period  of  its 
advancement;  and,  although  its  external  form 
and  organization  very  much  resemble  that  of 
the  foetus  of  other  mammiferous  animals  at  a 
similar  stage  of  their  advancement  when  they  are 
still  confined  to  the  uterus  of  the  mother,  their 
internal  organization  undergoes  at  the  time  of 
their  exclusion  the  same  remarkable  changes 
which  occur  at  birth,  and  which  are  connected 
with  aerial  respiration  and  the  independence  of 
the  vital  functions.* 

Monotrematous  generation. — The  generation 
of  the  Ornithorynchus  and  other  monotrema- 
tous animals  deserves  also  to  be  noticed  here 
as  differing  in  some  respects  from  that  of  other 
Mammalia;  but,  unfortunately,  this  subject, 
which  has  been  involved  in  obscurity  ever  since 
the  first  discovery  of  these  remarkable  animals, 
notwithstanding  that  several  important  facts 
have  been  recently  ascertained,  cannot  be  con- 
sidered as  completely  understood.  The  Orni- 
thorynchus and  Echidna  were  long  regarded  as 
holding  an  intermediate  place  in  respect  to 
their  organization  between  Mammalia  and 
Birds.  The  existence  of  mammary  glands  was 
denied  by  the  first  dissectors  of  these  animals  ; 
and  from  this  circumstance  principally,  toge- 
ther with  the  analogy  in  general  structure  al- 
ready alluded  to,  the  Ornithorynchus  was  be- 
lieved by  many  to  be  oviparous.  The  recent 
investigations  of  Owen  have  proved  the  ex- 
istence of  mammary  glands  as  well  as  the 
suckling  of  the  young,  while  they  at  the  same 
time  shew  that  the  generative  organs  and  the 
ova  within  the  ovaries  partake  in  a  great  degree 
of  the  oviparous  structured  In  this  approach 
to  the  oviparous  type,  however,  it  has  been 
satisfactorily  shewn  that  the  Ornithorynchus 
resembles  the  class  of  Reptiles  rather  than  that 
of  Birds.  The  ova  of  this  animal  have  not,  how- 
ever, been  found  in  any  of  its  haunts ;  and, 
although  no  one  has  yet  had  an  opportunity 
of  dissecting  the  gravid  uterus,  naturalists  are 
now  inclined  to  hold  the  opinion  that  it  bears 
its  young  alive.  Should  this  be  fully  proved 
to  be  the  case,  the  Ornithorynchus  may  with 
justice  be  considered  as  an  example  among 
mammiferous  animals  of  the  ovo-viviparous 
form  of  generation,  most  analogous  to  that 
occurring  in  the  Slow-worm  or  Adder;  the 
ovum  being,  at  the  time  of  its  descent  into  the 
oviduct,  of  proportionally  large  size,  and  there 
being  no  proper  placenta  or  intimate  organic 
union  between  the  mother  and  foetus. 

Comparison  of  animal  and  vegetable  repro- 

*  For  the  details  respecting  the  structure  and 
functions  of  the  generative  organs  of  the  Marsu- 
piata,  the  mode  of  passage  of  the  embryo  from  the 
uterus  to  the  pouch,  see  the  article  upon  the  Com- 
parative Anatomy  of  these  animals,  M ARSUPIATA. 
It  is  curious  to  note  that  until  the  discovery  of 
the  uterus  of  these  animals  by  Tyson,  the  vaguest 
conjectures  prevailed  respecting  their  mode  of 
reproduction,  it  being  even  supposed  by  some  that 
the  foetus  grew  from  the  first  attached  to  the  nipple, 
and  consequently  originated  as  a  bud. 

t  The  name  of  Monotremata  applied  to  these 
animals,  it  may  be  remarked,  means  with  (me  vent, 
they  having  a  cloaca. 


duction. — In  concluding  this  rapid  sketch,  it 
may  not  be  out  of  place  to  introduce  here  a 
few  remarks  upon  the  analogies  existing  be- 
tween animal  and  vegetable  reproduction. 

The  seed  of  plants  is  generally  regarded  as 
corresponding  to  the  egg  of  animals.  The 
seed  and  egg  correspond  in  being  both  the 
residence  of  the  germ  or  living  part  from 
which  the  new  organized  body  springs,  and 
also  in  both  containing  a  certain  quantity  of 
matter  destined  for  the  temporary  nourishment 
of  the  growing  embryo ;  but  the  germ  is  in  a 
different  state  in  the  seed  and  egg ;  for  while 
in  the  egg  none  of  the  parts  of  the  new  being 
are  visible  at  the  time  of  its  separation  from 
the  parent,  the  rudiments  of  the  embryo  are  fre- 
quently to  be  found,  small  but  simulating  in  some 
degree  the  plant,  in  the  germ  of  the  seed  when 
it  is  perfected,  and  before  the  commencement 
of  germination.  The  circumstances  favourable 
to  evolution  give  rise  to  the  development  of 
the  embryo  in  both,  but  in  the  animal  the 
influence  of  the  male  conferring  fecundity  on 
the  egg  makes  no  perceptible  alteration  in  the 
germ,  while  in  the  plant  no  part  of  the  seed, 
neither  cotyledon  nor  germ,  is  formed  unless 
fecundation  by  the  pollen  of  the  male  takes 
place ;  and  the  seed  is  not  separated  from  the 
ovary  or  place  of  its  production  until  the 
rudimentary  parts  of  the  embryo  are  already 
sketched  out. 

We  have  examples  of  non-sexual  repro- 
duction of  plants  among  the  Cryptogamia,  in 
which  the  new  plant  springs  from  sporules  or 
granules  endowed  with  the  independent  vital 
properties  of  the  seed. 

The  greater  number  of  monocotyledonous 
and  dicotyledonous  plants  may  be  regarded  as 
hermaphrodite,  as  both  the  seeds  and  pollen 
are  formed  on  the  same  individual,  while  in 
others  the  position  of  the  sexual  organs  on 
distinct  individuals  corresponds  with  the  more 
common  arrangement  in  the  animal  king- 
dom.* 

In  different  tribes  of  plants  we  also  observe 
examples  of  occasional  propagation  in  a  man- 
ner different  from  the  more  common  one  by 
seeds  or  sporules.  Thus  the  buds  and  branches, 
which  are  the  means  of  their  ordinary  growth 
and  increase,  may,when  removed,  be  capable  of 
independent  existence  and  give  rise  to  distinct 
plants,  or  even  when  still  on  the  parent  stock 
may  take  root  and  grow  anew.  Some  buds 
separate  naturally  and  are  evolved  in  the  man- 
ner of  seeds  when  placed  in  favourable  circum- 
stances ;  and  in  a  third  class  of  instances  sepa- 
rated buds  are  preserved  in  the  collections  of 
nutrient  matter  constituting  the  tuberous  and 
bulbous  roots  by  which  many  plants  are  pro- 
pagated. 

To  complete  the  enumeration  of  the  points 
of  analogy  between  animal  and  vegetable  re- 
production, it  may  be  stated  that  there  is  the 
same  reason  for  believing  in  the  spontaneous 
generation  of  some  of  the  Cryptogamic  plants 
as  in  that  of  Infusorial  animals. 

*  As  in  strictly  Hermaphrodite,  Monoecious,  and 
Dioecious  plants. 


438 


GENERATION. 


The  following  table  is  intended  to  exhibit  a 
synoptical  view  of  the  various  forms  of  the 


Fissiparous 
Gemmiparous  . . 


Hermaphrodite. 


Dioecious 


III.  REPRODUCTIVE  FUNCTION   IN  MAN  AND 
THE  HIGHER.  ANIMALS. 

1.  Sketch  of  this  Junction  in  man. — In  now 
proceeding  to  a  more  detailed  account  of  the 
function  of  generation,  our  description  must  be 
confined  to  the  process  of  reproduction  in  the 
human  species  and  in  those  animals  which  are 
most  nearly  allied  to  man. 

The  following  may  be  mentioned  as  the 
principal  steps  of  the  reproductive  process  in 
the  female  of  the  human  species. 

The  human  offspring  is  derived  from  an  egg 
like  that  of  all  the  more  perfect  animals.  The 
egg  is  gradually  formed  in  the  Graafian  vesicle 
of  the  ovary  at  the  period  of  maturity.  In 
productive  sexual  union  the  vagina  and  uterus 
receive  a  certain  quantity  of  the  male  seminal 
fluid,  and  a  series  of  changes  are  induced  in 
the  female  generative  system  which  have  the 
effect  of  dislodging  one  or  more  ova  from  their 
residence  in  the  ovary,  and  of  bringing  these 
ova  into  contact  with  the  seminal  fluid,  in 
order  that  they  may  be  fecundated  or  rendered 
fruitful.  The  mechanism  of  the  discharge  of 
the  ova  is  the  following.  The  Graafian  vesicle 
swells,  and  bursts  at  its  most  prominent  part. 
The  ovum  escaping  from  its  interior  is  received 
by  the  fimbriated  cavity  at  the  commencement 
of  the  Fallopian  tube,  along  which  tube  it 
gradually  passes  until  it  reaches  the  interior  of 
the  uterus,  where  it  arrives  probably  in  ten  or 
twelve  days  after  sexual  union.  There  is  every 
reason  to  believe  that  before  the  ovum  reaches 
the  uterus  it  has  already  been  exposed  in  some 
part  of  the  genital  organs  to  the  influence  of 
the  male  semen,  and  that  it  is  consequently 
fecundated.  We  shall  have  occasion  after- 
wards to  inquire  more  minutely  into  the  place 
and  manner  of  this  fecundation.  The  female 
is  now  said  to  have  conceived  or  to  be  impreg- 
nated, and  the  ovum  to  be  fecundated.  We 
shall  endeavour,  for  the  sake  of  clearness,  to 
bring  the  history  of  the  steps  of  this  process 


reproductive  process  occurring  in  different 
classes  of  animals. 

Parent  splits,  each  part  a  new  animal. 

1.  Transverse. 

2.  Longitudinal. 

3.  Irregular. 
Parent  splits  and  discharges  the  young. 
Budding  upon  the  parent  stock. 
Separated  buds.    Gemmae  or  sporules. 

1.  On  all  parts  of  the  body. 

2.  On  one  part  or  organ  only. 
Both  sexual  organs  on  one  individual. 

1.  Self-impregnation. 

2.  Mutual  impregnation. 
Oviparous,  laying  eggs  which  are  hatched. 

1.  External  fecundation. 

2.  Internal  fecundation. 
Ovo-viviparous.    Eggs  hatched  within  the 

maternal  body. 
Mammiferous,  suckling  the  young. 

1 .  Monotrematous. 

2.  Marsupial. 

3.  Placental  or  strictly  vivi- 
parous. 

under  the  three  distinct  heads  of,  first,  the 
changes  of  conception  as  regards  the  female, 
secondly,  the  process  of  fecundation  as  relating 
to  the  male,  and  thirdly,  the  effects  of  the  union 
of  the  male  and  female  product. 

Before  the  ovum  reaches  the  uterus  a  change 
has  already  commenced  in  the  interior  of  that 
organ,  which  in  its  farther  progress  has  for  its 
object  to  bring  about  an  organic  union  between 
the  uterus  and  the  foetus  with  its  coverings.  The 
minute  embryo  soon  becomes  visible  in  the 
ovum,  has  envelopes  formed  over  it  which 
become  connected  with  the  lining  membrane 
of  the  uterus,  and  as  it  advances  in  growth 
continually  receives  a  supply  of  nourishment 
from  the  bloodvessels  of  the  uterus.  It  is 
nourished  in  this  way  during  the  whole  of  its 
intra-uterine  life,  at  the  termination  of  which 
the  child  is  brought  into  the  world  or  born, 
being  expelled  from  the  uterus  by  those  pain- 
ful efforts  and  contractions  of  the  uterus  con- 
stituting parturition  or  labour.  The  child  is 
row  capable  of  being  nourished  by  digestion 
of  food  in  the  stomach,  independently  of 
any  organic  connexion  with  the  mother,  and 
breathes  air  by  its  lungs.  Although  all  or- 
ganic connexion,  however,  between  the  mother 
and  child  is  now  dissolved,  yet  the  infant  is 
for  a  time  dependent  on  the  mother  for  nou- 
rishment, receiving  by  sucking  from  the  mam- 
ma- the  milk,  which  it  assimilates  by  its  own 
independent  powers.  In  the  present  article 
our  object  is  to  describe  only  the  processes  of 
conception  and  fecundation,  referring  to  the 
article  Ovum  for  an  account  of  the  growth  of 
the  foetus,  and  to  the  articles  Uterus,  Ovary, 
&c.  for  the  more  minute  anatomical  and 
functional  relations  of  these  organs  in  the 
unimpregnated  and  impregnated  states. 

Organs  of  reproduction. — The  organs  of 
reproduction  in  both  sexes  are  frequently  divi- 
ded by  anatomists  into  external  and  internal, 
according  as  they  are  situated  more  or  less  near 


GENERATION. 


439 


the  surface  of  the  body  ;  but  a  more  suitable 
arrangement  of  these  organs  in  a  functional 
point  of  view  is  that  which  is  founded  on  the 
part  which  each  of  them  is  destined  to  perform 
in  the  generative  act.  The  male  organs  consist 
•of  the  penis  and  urethra,  testicles,  seminal  vesi- 
cles, seminal  ducts,  prostatic  body, and  Cowper's 
glands:  the  female  organs,  of  the  vulva, clitoris 
and  nymphas,  vagina,  uterus,  Fallopian  tubes, 
and  ovaries.  The  testicles  in  the  male  and  the 
ovaries  in  the  female  are  the  productive  organs, 
secreting  or  forming  by  an  organic  process  the 
product  of  each  respective  sex  ;  the  vasa  defe- 
rentia  and  vesiculae  seminales  conduct  and 
retain  for  a  time  the  seminal  fluid ;  the  Fallo- 
pian tubes  conduct  downwards  the  ovum  from 
the  ovary  to  the  uterus ;  the  uterus  receives 
and  retains  the  ovum  during  pregnancy  or  the 
formation  of  the  child.  These  constitute  the 
internal  organs ;  the  remaining  parts  are  the 
external  organs,  and  are  chiefly  connected  with 
sexual  union  or  the  expulsion  of  the  products 
from  the  body.  The  glans  penis,  the  clitoris, 
and  the  neighbouring  parts  are  the  seat  of  that 
feeling  which  accompanies  the  venereal  act: 
the  penis,  with  its  urethra,  serves  to  conduct 
the  seminal  fluid  into  the  vagina  and  uterus  of 
the  female  :  the  vagina,  besides  receiving  the 
seminal  fluid,  is  the  issue  for  the  child  when 
it  is  expelled  from  the  uterus  in  parturition. 

Puberty .—It  is  only  during  a  stated  period 
of  life  that  animals  are  capable  of  reproduction. 
In  infancy,  youth,  and  old  age  the  functions 
of  the  sexual  organs  are  in  abeyance.  The 
name  of  puberty  is  given  to  that  period  of  life 
at  which  either  sex  first  becomes  capable  of  re- 
production, at  which  time  various  important 
structural  and  functional  changes  occur  both 
in  the  sexual  organs  and  in  the  whole  eco- 
nomy. 

These  changes  are  upon  the  whole  more 
marked  in  the  female  than  in  the  male,  a  cir- 
cumstance which  may  be  attributed  to  the 
longer  and  more  intimate  connexion  of  the 
female  with  the  product ;  the  maternal  parent 
affording  a  supply  of  nourishment  to  the  child 
during  the  whole  of  its  intra-uterine  life,  while 
the  male  does  no  more  than  furnish  momenta- 
rily a  small  quantity  of  the  seminal  fluid 
necessary  for  fecundation. 

Structural  differences  of  the  sexes. — In  in- 
fancy and  youth  the  two  sexes  do  not  differ 
materially  in  the  general  shape  of  the  body, 
nor  in  physical  powers ;  but  as  the  age  of 
puberty  approaches,  and  the  sexual  organs 
undergo  those  changes  which  fit  them  for  the 
performance  of  their  appropriate  functions,  the 
male  and  female  bodies  become  altered  in 
form,  and  acquire  a  more  marked  difference, 
while  the  mental  and  physical  powers  also  par- 
take of  this  discrepancy. 

We  shall  do  no  more  than  mention  here  the 
most  striking  of  these  peculiarities,  as  a  more 
detailed  account  of  them  belongs  to  another 
place. 

Besides  these  differences  which  belong  im- 
mediately to  the  sexual  conformation,  the  com- 
paratively broader  shoulders  and  wider  chest 
of  the  male,  and  the  larger  pelvis  and  ab- 


domen of  the  female,  are  universally  known 
as  constituting  the  chief  peculiarities  in  the 
general  contour  of  the  body.  The  smaller  size 
of  the  whole  body  in  the  female,  amounting 
in  general  to  a  tenth  of  the  whole  height,  the 
greater  slenderness  of  the  female  frame,  the  less 
prominence  of  the  muscles,  the  more  tapering 
and  rounded  shape  of  the  limbs,  the  greater 
quantity  of  fat  under  the  skin  and  elsewhere, 
the  smaller,  smoother,  and  finer  bones,  and 
the  more  delicate  texture  of  some  other  parts 
of  the  body,  are  all  peculiarities  of  female 
conformation  contrasting  with  the  opposite 
qualities  in  the  male  body.  As  belonging 
to  the  male  may  be  mentioned  the  low  and 
rough  voice  from  the  larger  size  of  the  larynx 
and  longer  vocal  cords,*  the  occurrence  of 
hair  on  the  chin,  upper  lip,  and  cheeks,  as 
well  as  over  the  body  and  limbs,  in  which 
situations  it  is  rarely  met  with  in  the  female, 
the  greater  physical  power  and  activity,  capa- 
bility of  enduring  fatigue  and  daring,  &c. 

As  these  changes  in  either  sex  are  gradually 
developed,  hair  grows  on  the  skin  covering  the 
symphysis  pubis,  in  the  neighbourhood  of  the 
genital  organs,f  and  later  under  the  axillae. 

The  local  changes  attendant  upon  puberty 
in  the  male  are  the  enlargement  of  the  penis, 
its  more  frequent  erection,  and  accompaniment 
of  this  by  the  sexual  feeling  ;  the  enlargement 
of  the  testicles,  vesicute  seminales,  prostatic 
gland,  and  other  accessory  parts;  the  more 
depending  condition  of  the  testicles  in  the 
scrotum  ;  the  secretion  of  a  certain  quantity 
of  the  seminal  and  prostatic  fluids ;  and,  after 
the  attainment  of  the  full  sexual  powers,  the 
occasional  spontaneous  emission  of  some  of 
the  seminal  fluid,  occurring  in  general  at  night 
during  sleep,  and  being  accompanied  by  some 
sexual  feeling  in  dreams. 

In  the  female  at  this  period,  both  external 
and  internal  organs  undergo  a  considerable 
and  rapid  enlargement ;  the  mons  veneris  and 
external  labia  become  more  full ;  the  clitoris 
and  nymphffi  in  many,  but  not  in  all,  become 
susceptible  of  a  certain  degree  of  swelling  or 
erection ;  the  breasts  enlarge,  the  vesicles  in 
the  ovaries  become  dilated,  and  some  of  them 
more  prominent,  and  there  is  established  a 
periodical  discharge  of  a  certain  quantity  of  a 
sanguineous  fluid  from  the  internal  genital 
organs. 

Menstruation. — This  periodical  loss  of  blood 
demands  the  attention  of  the  physiologist  as 
one  of  the  most  remarkable  of  the  sexual  pecu- 
liarities of  the  human  female,  and  as  bearing 
an  intimate  relation  not  only  to  the  generative 
process,  but  to  most  of  the  other  functions  of 
the  economy. 

The  periodical  recurrence  of  the  discharge  of 
blood  every  lunar  month  or  twenty-eight  days 

*  Comparative  measurements  have  been  made 
of  the  length  of  the  vocal  cords  in  boys  imme- 
diately before  and  alter  puberty,  and  those  of  the 
young  men  have  been  found  to  be  nearly  double  the 
length  of  those  of  the  boy. 

f  Hence  the  name  of  this  bone  and  of  the  period 
of  life  of  which  we  are  now  speaking — pubes  and 
puberty. 


440 


GENERATION. 


has  given  to  it  the  name  of  menses  or  men- 
struation :  the  Greek  word  catamenia  is  also 
employed  to  denote  it  by  medical  men,  and 
the  English  expressions  of  "  the  illness"  or 
"  the  courses"  are  those  in  most  common  use 
among  the  vulgar. 

The  menstrual  flow  of  blood  lasts  usually 
for  about  five  days,  beginning  and  leaving 
off  gradually,  and  being  in  greatest  quantity 
towards  the  middle  of  the  period.  The  in- 
terval is  thus  generally  about  twenty-three  days. 
The  discharge  in  general  takes  place  slowly,  or 
drop  by  drop. 

The  menstrual  flow  of  blood  is  preceded  in 
most  women  by  some  symptoms  of  fever,  a 
quicker  and  fuller  pulse  than  usual,  languor, 
headach,  pains  in  the  back,  and  frequently  in 
the  hypogastria  or  region  of  the  ovaries,  and 
by  many  other  symptoms  of  general  derange- 
ment of  the  functions,  particularly  in  weak  or 
unhealthy  women.  In  young  women  upon 
the  occasion  of  the  first  appearance  of  the 
menses  all  these  symptoms  are  frequently  more 
strongly  marked. 

Menstruation  may  be  regarded  as  the  most 
certain  sign  of  the  arrival  of  puberty,  and  of 
the  fitness  of  the  human  female  for  marriage, 
as  there  are  very  few  instances  on  record  in 
which  conception  has  taken  place  before  the 
occurrence  of  the  menstrual  discharge.  It 
continues  for  the  whole  of  that  period  of  life 
during  which  women  are  capable  of  bearing 
children ;  and  after  this,  when  it  ceases,  a 
considerable  change  in  the  female  constitution 
ensues  :  the  "  change  of  life "  or  "  critical 
period"  is  said  to  have  arrived,  from  the  liabi- 
lity there  then  is  to  the  conversion  of  the 
plethoric  state,  previously  relieved  by  men- 
struation, into  some  morbid  affection  either  of 
the  sexual  or  other  organs  of  the  body. 

During  menstruation,  the  uterus,  vagina, 
ovaries,  and  other  parts  of  the  genital  organs 
are  usually  more  vascular  and  turgid  with 
blood  than  in  the  interval ;  the  mammae,  which 
exhibit  at  all  times  a  remarkable  sympathy 
with  the  condition  of  the  uterus,  frequently 
participate  in  this  increased  activity  at  the 
menstrual  period,  as  they  then  swell  and  be- 
come hard. 

Menstruation  consists  essentially  in  the 
exudation  of  a  fluid  resembling  blood  from 
the  female  genital  organs,  and  principally  from 
the  uterus.  Haller  states  that  the  blood  has 
actually  been  observed  to  proceed  from  the 
uterus  in  women  labouring  under  prolapsus 
of  that  organ,  and  John  Hunter  as  well  as 
others  have  found  the  cavity  of  the  uterus  filled 
with  the  fluid  in  women  who  have  died  during 
menstruation. 

Menstruation  usually  ceases  during  pregnancy, 
and  in  the  majority  of  women  during  lactation 
also.  In  those  instances  in  which  the  monthly 
flow  has  continued  to  take  place  during  preg- 
nancy, there  is  reason  to  believe,  according  to 
Haller,  that  it  may  have  proceeded  from  the 
upper  part  of  the  vagina,  as  the  first  changes 
attendant  upon  utero-gestation  usually  close 
firmly  the  neck  of  the  uterus. 

The  quantity  of  fluid  which  exudes  during 


one  menstrual  period  amounts  in  general  to 
five  or  six  ounces ;  but  this  is  subject  to  great 
variation  from  the  mode  of  life  of  the  indivi- 
dual, state  of  her  health,  diet,  and  other 
circumstances.  The  quantity  is  usually  greatest, 
ceeteris  paribus,  in  healthy  women  living  well, 
but  the  increase  of  the  quantity  above  a  certain 
point  or  its  diminution  below  another  are 
equally  to  be  regarded  as  unnatural  or  diseased 
states  of  the  action.  In  tropical  countries  the 
quantity  is  greater  than  in  more  temperate 
regions,  amounting  occasionally  to  twelve  or 
even  twenty  ounces.  In  Lapland  and  some 
other  northern  countries  the  quantity  is,  on  the 
other  hand,  much  below  the  mean,  being 
occasionally  as  low  as  three  ounces ;  and  yet 
in  both  these  situations  the  women  are  to  be 
regarded  as  within  the  bounds  of  health. 

The  quantity  of  fluid  lost  in  menstruation  is 
increased  by  all  those  circumstances  which  cause 
a  determination  of  blood  to  the  pelvis  or  its 
contained  viscera;  hence  the  effect  of  posture, 
irritating  diuretics,  drastic  purgatives,  and  those 
medicines  termed  emmenagogues. 

The  nature  of  the  fluid  discharged  in  men- 
struation has  not  yet,  we  believe,  been  investi- 
gated with  sufficient  accuracy.  It  bears  a  close 
resemblance  to  blood,  having  generally  the 
colour  of  the  venous  kind.  It  is  generally 
fluid,  but  sometimes  coagulates  from  exposure 
to  air:  it  is  generally  believed  to  contain  less 
fibrine  than  blood,  and  to  be  less  prone  to 
putrefaction. 

Respecting  the  causes  of  the  menstrual  dis- 
charge and  its  uses  in  the  economy,  many  very 
absurd  hypotheses  have  been  advanced  in  me- 
dical writing's.  It  was  a  common  belief  among 
the  ancients  that  the  menstrual  fluid  exerted  a 
baneful  influence  on  every  living  object,  plant, 
or  animal,  and  many  of  the  institutions  and 
laws  of  antiquity  shew  that  this  natural  process 
was  looked  upon  with  abhorrence.  The  corres- 
pondence in  the  length  of  time  of  the  moon's 
changes  with  the  recurrence  of  the  menstrual 
period  induced  many  to  believe  in  an  influence 
exerted  by  the  moon  on  the  female  generative 
system ;  but  the  error  of  such  a  notion  is  suffi- 
ciently proved  by  the  circumstances,  first,  that 
more  women  are  not  found  to  menstruate  at  one 
period  of  the  moon's  changes  than  at  another., 
and,  second,  that  the  women  of  any  place  men- 
truate  at  all  different  times.  Besides  this,  many 
women  do  not  menstruate  regularly  every  lunar 
month.  In  some  this  change  takes  place 
every  three  weeks,  in  others  every  fortnight, 
and  there  are  many  in  whom  there  is  a  varia- 
tion of  one  or  two  days  on  either  side  of  the 
common  period  of  twenty-eight  days. 

When  we  consider  the  circumstances  pre- 
viously mentioned  respecting  the  intimate  con- 
nexion subsisting  between  the  menstrual  flow 
and  the  processes  of  reproduction,  we  shall  be 
led  rather  to  the  opinion  that  menstruation  is 
to  be  regarded  as  a  means  of  relieving  the 
female  system  periodically  from  an  overplus  of 
blood  which  exists  during  the  whole  of  the 
time  in  which  it  is  capable  of  propagation.  It 
occurs  at  this  period  of  life  only,  it  generally 
ceases  during  pregnancy,  and  it  may  therefore 


GENERATION. 


441 


correctly  be  regarded  as  the  indication  of  the 
presence  in  the  system  of  that  quantity  of 
nutrient  matter,  which,  during  pregnancy,  is 
destined  to  serve  for  the  nourishment  of  the 
child.  We  say  that  this  flow  does  no  more 
than  indicate  the  surplus  quantity  of  blood  in 
the  female  genital  organs ;  for,  as  Burdach 
remarks,  the  loss  of  six  ounces  of  blood  for 
ten  successive  lunar  periods  amounts  to  only 
three  pounds  twelve  ounces,  whereas  the  foetus 
and  its  appendages  during  that  period  attain 
the  weight  of  from  ten  to  fifteen  pounds,  to 
which  we  might  add  the  enormously  increased 
weight  of  the  uterus  in  order  to  estimate  the 
whole  addition  which  is  made  to  the  uterine 
system  during  pregnancy.  Again,  during  lac- 
tation or  nursing  the  tendency  to  a  super- 
abundance of  blood  or  plethora  in  the  uterus 
is  generally  relieved  by  the  flow  of  milk  from 
the  mammae,  which,  as  has  already  been 
remarked,  sympathize  very  constantly  with  the 
uterus  and  other  parts  of  the  generative  system. 

Such  a  tendency  to  plethora  as  that  we  have 
just  alluded  to,  it  is  scarcely  necessary  to  remark, 
can  have  no  connexion  with  lunar  or  planetary 
influences,  and  we  are,  perhaps,  more  justified 
in  classing  it  along  with  those  other  changes  of 
the  economy  which  indicate  a  remarkable  ten- 
dency in  the  human  constitution  to  periodical 
recurrence  of  its  actions. 

The  crises  of  fevers  on  days  terminating 
periods  which  are  most  frequently  of  the  dura- 
tion of  seven,  fourteen,  twenty-one,  or  twenty- 
eight  days,  are  of  this  kind  ;  and  it  is  deserving 
of  notice  that  menstruation  recurs  more  fre- 
quently in  periods,  the  number  of  days  of 
which  are  multiplies  of  seven,  than  in  any 
others.* 

It  has  been  attempted  to  be  shewn  that  the 
male  is  subject  to  a  periodical  plethora  in  some 
respects  similar  to  that  which  gives  rise  to 
menstruation  in  the  female,  but  without  any 
just  reason,  unless  we  choose  to  consider  as 
such  the  gradual  accumulation  of  seminal  fluid, 
which  frequently  takes  place  in  healthy  men  of 
sanguine  temperament,  and  which  gives  rise 
to  its  periodical  emission. 

With  regard  to  menstruation  we  shall  only 
farther  remark  that,  according  to  Ilaller,  Bur- 
dach, and  some  others,  women  are  more  liable 
to  become  pregnant  immediately  or  within  a 
few  days  after  the  cessation  of  menstruation 
than  at  other  parts  of  the  interval ;  the  probable 
reason  of  which  will  appear  from  details  given 
in  a  subsequent  part  of  this  article. 

Periodical  heat  in  animals. — None  of  the 
lower  animals  in  the  natural  state  appear  to  be 
subject  to  anything  like  a  menstrual  change  or 
periodical  discharge  of  blood.  In  lascivious 
Apes  and  in  some  of  the  domestic  animals  fed 

*  According  to  the  researches  of  Mr,  Roberton  of 
Manchester,  detailed  in  an  interesting  paper,  pub- 
lished in  the  Edinburgh  Med.  and  Suig.  Journal, 
vol.  xxxviii.  p.  237,  out  of  100  women,  in  sixty-eight 
the  menstrual  discharge  returned  every  fourth  week  ; 
in  twenty-eight  every  third  week  ;  in  one  every  se- 
cond week  ;  in  ten  at  irregular  intervals.  These 
varieties  usually  exist  as  family  and  constitutional 
peculiarities. 

VOL.  11. 


highly,  an  exudation  of  bloody  mucus  from 
the  vagina  and  external  genital  organs  of  the 
females  sometimes  occurs,  but  this  is  manifestly 
quite  different  from  menstruation.  There  is, 
however,  in  most  of  the  lower  animals  a  very 
obvious  periodicity  in  the  functions  of  the 
reproductive  organs;  for  while  the  human 
female  is,  during  a  certain  period  of  life, 
nearly  equally  fit  for  propagation  at  all  times, 
this  is  the  case  with  very  few  animals,  and, 
indeed,  chiefly  among  those  living  in  the  un- 
natural state  of  domesticity. 

At  certain  seasons  of  the  year  there  occurs 
in  most  of  the  lower  animals  a  determination 
of  blood  to  the  genital  organs  of  the  female, 
accompanied  by  sexual  desire,  which  leads 
them  to  the  propagation  of  their  species.  This 
state  of  excitement,  generally  named  "  the 
heat,"*  lasts  for  a  longer  or  shorter  period ;  in 
the  ewe  for  twenty-four  hours  only,  in  the 
cow  and  mare  for  a  few  days,  in  the  bitch 
nine  or  ten  days,  and  in  the  hen-pheasant  for 
as  long  as  two  months.  In  most  animals,  after 
it  has  run  its  accustomed  course,  it  disappears 
naturally,  but  it  is  more  certainly  and  sooner 
dispelled  by  fruitful  sexual  union. 

The  heat  belongs  more  properly  to  the  female 
than  to  the  male,  as  there  are  many  species 
whose  females  receive  the  male  only  at  par- 
ticular seasons,  while  the  male  is  at  all  times 
fit  for  propagation.  In  others,  constituting  the 
majority  of  instances,  the  male  organs  are  sub- 
ject to  the  same  periodical  increase  of  activity 
as  the  female.  The  male  in  these  animals  is 
usually  in  heat  at  an  earlier  period  than  the 
female.f 

In  some  animals  there  is  a  more  frequent 
periodical  return  of  the  heat  than  in  others; 
thus  the  ewe  which  remains  unimpregnated 
conies  in  heat  every  fourteen  days ;  the  cow 
and  some  apes,  the  mare,  ass,  and  buffalo 
every  four  weeks;  the  sow  every  fifteen  or 
eighteen  days ;  but  in  these  animals  the  high 
feeding  attendant  on  domesticity  may  very 
probably  occasion  a  more  frequent  and  less 
natural  return  of  the  period  of  heat  than  would 
occur  in  the  wild  state. 

It  would  appear  that  the  season  of  the  year 
at  which  animals  most  commonly  breed  is 
subject  to  very  many  and  extensive  variations, 
according  to  the  temperature,  latitude,  and 
other  circumstances  connected  with  the  country 
which  they  inhabit. 

During  the  continuance  of  the  heat  a  peculiar 
odour  is  exhaled  from  the  genital  organs,  and 
there  exudes  chiefly  from  the  external  organs 
some  bloody  mucus,  which,  in  some  lascivious 
apes,  resembles  blood  so  much  as  to  have 
given  rise  to  the  belief  already  alluded  to  that 
these  animals  menstruate. 

Age  at  which  puberty  occurs. — The  appear- 

*  Termed  the  Itut  in  the  deer,  wild  boar,  tkc. 

t  In  some  male  animals  the  signs  of  heat  are 
very  apparent.  The  fine  colour  of  the  plumage  of 
most  male  birds  in  the  breeding  season,  the  deep 
colour  of  the  comb,  &c.  in  gallinaceous  fowls,  the 
thickness  and  bushy  hair  of  the  deer's  neck,  the 
greatly  enlarged  size  of  the  testicles  in  the  cock- 
sparrow,  may  be  mentioned  as  familial'  examples. 

2  G 


442 


GENERATION. 


ance  of  puberty  is  gradual  in  both  sexes,  but, 
upon  the  whole,  more  slow  in  the  male  than 
in  the  female.  The  age  at  which  it  takes  place 
varies  in  the  same  and  in  different  countries 
according  to  the  mode  of  life,  physical  and 
moral  education,  and  other  circumstances.  It 
takes  place  at  an  earlier  age  in  woman  than  in 
man :  in  the  former  most  frequently  in  this 
country  at  from  the  age  of  thirteen  to  sixteen 
years,  in  the  latter  from  fifteen  to  eighteen 
years;  but  instances  are  not  unfrequent  of 
girls  menstruating  and  of  boys  passing  into 
manhood  one  or  two  or  even  more  years  sooner 
or  later  than  the  above-mentioned  periods,  as 
from  ten  or  eleven  to  twenty  or  twenty-two 
years.* 

These  variations  are  to  be  considered  as 
dependent  on  constitution  in  the  greater  num- 
ber of  instances;  but  in  respect  to  their 
ocbasional  causes,  it  may  be  stated  that  all 
those  circumstances  which  produce  a  determi- 
nation of  blood  to  the  sexual  organs  or  pelvic 
viscera,  which  relax  the  body  generally,  or 
turn  the  attention  of  the  young  to  the  sexual 
function,  tend  to  bring  on  sooner  than  natural 
the  local  changes  of  puberty.  Warm  rooms, 
a  sedentary  mode  of  life,  particular  kinds  of 
reading,  and  some  bad  habits  are  all  hurtful  in 
this  respect. 

According  to  the  observations  of  many  tra- 
vellers, puberty  arrives  sooner  in  warm  than 
in  temperate  climates ;  and  some  have  hence 
too  hastily  concluded  that  the  warmth  of  the 
tropical  country  has  been  the  cause  of  the  more 
precocious  appearance  of  menstruation  in  wo- 
men and  puberty  in  men,  an  opinion  the  error 
of  which  is  shev\n  by  the  fact  that  instances  of 
very  early  puberty  are  not  unfrequently  met 
•with  in  high  northern  latitudes. f    The  occur- 

*  According  to  Mr.  Roberton's  observations  pre- 
viously quoted,  the  following  are  the  ages  at  which 
450  women  began  to  menstruate  : 


In  their  1 1th 

year 

10 

„  12th 

19 

„  13th 

53 

„  14th 

85 

„  15th 

>> 

97 

„  16th 

76 

„  17th 

>* 

57 

„  18th 

26 

,,  19th 

23 

„  20th 

4 

This  table  shews  that  the  age  of  puberty  of  females 
in  this  country  extends  over  a  considerable  number 
of  years,  ind  is  more  equally  distributed  than  is 
commonly  alleged. 

t  The  opinion  that  menstruation  happens  at  an 
earlier  age  in  warmer  climates  is  very  generally  enter- 
tained, as  may  be  seen  by  a  reference  to  the  works 
of  Haller,  Boerhaave,  Deninan,  Burns,  Dewees, 
and  others.  Mr.  Roberton  has  successfully  shewn 
its  inaccuracy  by  an  appeal  to  the  facts  stated  by 
modern  travellers,  as  llearne,  Franklin,  Richard- 
son, and  Back  with  regard  to  the  Northern  Cana- 
dian Indians ;  by  Lyon  and  Parry  with  respect  to 
the  Esquimaux  ;  by  Clarke  in  reference  to  the 
Laplanders;  and  by  Tonke  in  relation  to  the 
Northern  Russians  ;  all  of  whi<h  shew  that  puberty 
is  attained  in  the  arctic  regions  at  least  as  early 
as  in  more  temperate  climates.  On  the  other  hand, 
from  the  evidence  of  Crawford  and  Raffles  relative 
to  the  inhabitants  of  the  Indian  Archipelago,  of 
Messrs.  Ellis  and  Browne  (missionaries)  in  regard 


rences  of  marriages,  therefore,  or  sexual  union 
at  the  early  age  of  six  or  seven  years  in  the 
South  Sea  Islands  and  elsewhere  is  to  be  looked 
upon  rather  as  a  proof  of  the  barbarous  and 
debased  state  of  civilization  of  these  people, 
than  taken  as  an  evidence  of  their  being  fitted 
by  nature  for  the  functions  of  propagation  at 
the  period  of  life  now  mentioned. 

There  do  sometimes  occur,  however,  in  all 
nations  unfortunate  examples  of  precocity  in 
the  development  of  the  sexual  organs  and 
activity  of  their  functions.  Thus  in  male  or 
female  children  of  four  and  even  of  only  three 
years  old  all  the  changes  of  the  sexual  organs, 
and  some  of  those  of  the  body  generally,  which 
belong  to  puberty  of  a  more  advancedand  natural 
age,  take  place.  The  attention  of  such  children 
is  soon  called  by  their  local  feelings  to  the 
condition  of  the  sexual  organs,  and  vicious 
habits  are  induced,  which;  from  the  misery 
they  carry  along  with  them,  it  becomes  the 
duty  of  the  medical  man  to  counteract  by  all 
the  resources  of  his  art. 

Period  of  life  during  which  the  generative 
Junction  is  exercised. — The  length  of  time  du- 
ring which  the  male  and  female  of  the  human 
species  retain  the  power  of  propagation  is  sub- 
ject to  the  same  variations  which  attend  the 
arrival  of  the  age  of  puberty.  The  most  healthy 
women  are  in  general  capable  of  bearing  chil- 
dren between  the  ages  of  fifteen  and  forty-five, 
or  for  a  period  of  thirty  years.  Men  retain  the 
powers  of  their  sex  for  a  longer  time,  as  from 
the  age  of  seventeen  to  sixty  or  seventy,  that  is, 
for  forty-five  or  fifty  years.  There  are,  however, 
on  record  instances  of  both  sexes,  but  more 
especially  the  male  sex,  having  retained  their 
respective  powers  for  a  longer  period  than  that 
just  stated  ; — of  women  menstruating  a  second 
time  (after  the  cessation  of  this  function  at  the 
usual  period)  at  the  age  of  sixty  or  seventy,*" 
and  in  one  or  two  instances  bearing  a  child  at 
that  advanced  age  ; — of  propagation  in  the  male, 
sex  to  the  age  of  seventy,  eighty,  and  ninety, 
and  in  the  celebrated  case  of  old  Parr  even  to 
that  of  one  hundred  and  thirty  years.f 

Among  the  lower  animals  the  variations  in  this 
respect  are  so  numerous  as  to  preclude  the  pos- 
sibility of  our  mentioning  even  the  more  im- 

to  those  of  Polynesia ;  of  Dr.  Winterbottom  on 
the  native  Africans  round  Sierra  Leone;  of  the 
laws  of  the  Koran  in  regard  to  the  Arabs  ;  and  of 
the  observations  by  Russel  on  the  Egyptians,  Mr. 
Roberton  endeavours  to  prove  that  though  early 
marriages  are  common  in  warm  and  equinoctial 
countries,  yet  the  period  of  puberty  and  of  the 
capability  of  procreating  is  nearly  the  same  as  in 
temperate  and  noithern  latitudes.  Mr.  Roberton 
is  therefore  induced  to  form  the  conclusion  that  the 
variations  from  the  standard  or  more  common 
period  of  puberty  in  different  nations  are  not  greater 
than  the  individual  differences  to  be  observed  in 
our  own  country,  and  that  the  opinion  above 
referred  to  ought  to  be  looked  upon  as  a  vulgar 
error. 

*  These  instances  are  very  rate  indeed.  Mr. 
Roberton  states  that  of  3000  women  delivered  in  the 
Manchester  Lying-in  Hospital,  only  one  was  above 
fifty  years  of  age. 

t  See  Halter's  Elementa  for  an  enumeration  of 
such  examples. 


GENERATION. 


443 


portant  in  this  place.  The  male  of  some  in- 
sects, it  is  well  known,  die  as  soon  as  they  have 
fecundated  the  female  ;  many  plants  and  ani- 
mals propagate  only  once,  while  others  give 
rise  to  many  successive  families ;  but  we  are 
not  acquainted  with  any  general  law  to  which 
such  differences  can  be  referred. 

Effects  of  castration. — Nothing  illustrates  in 
a  more  striking  manner  the  intimate  relation 
which  the  sexual  function  bears  to  the  general 
organization  and  functions  of  the  body  than  the 
effect  of  castration,  or  the  removal  of  the  forma- 
tive and  essential  parts  of  the  sexual  organs  in 
either  sex.  When  both  the  ovaries  or  testicles 
have  been  removed  or  destroyed,  the  power  of 
propagation  is  of  course  entirely  lost.  When 
this  operation  is  performed  at  an  early  age, 
there  is  also  caused  a  remarkable  alteration  of 
the  constitution  and  general  habit  of  body  of 
the  animal.  The  functional  and  structural  pe- 
culiarities of  the  body  become  less  marked,  and 
there  is  a  great  tendency  in  general  to  the  uni- 
versal deposition  of  fat  in  different  textures. 

In  the  castrated  male,  the  form  and  texture 
of  the  body  approaches  that  of  the  female,  and 
the  mental  faculties  seem  to  partake  in  a  certain 
degree  of  a  similar  modification.  The  voice 
remains  high  and  clear;  and  hence  the  barba- 
rous custom  prevailing  to  the  present  day  in 
Italy  and  elsewhere  of  making  eunuchs  for  the 
sake  of  their  high  voices  in  singing. 

In  the  spayed  female,  on  the  other  hand, 
there  is  a  certain  approach  to  the  characters  of 
the  male.  In  women  in  whom  it  has  been 
necessary  to  extract  the  ovaries  on  account  of 
disease,  the  bones  and  muscles  have  been  ob- 
served to  have  a  more  masculine  contour,  the 
voice  is  harsh  like  a  man's,  the  breasts  are  flat, 
and  there  is  frequently  a  formidable  beard,  and 
hair  on  different  parts  of  the  body. 

The  same  or  similar  circumstances  have  been 
remarked  in  those  unfortunate  malformed  indi- 
viduals who  present  an  approach  to  hermaphro- 
dite formation,  or  in  whom  there  is  imperfect 
development  of  either  the  male  or  female  geni- 
tal organs.  So  also  it  has  been  observed  that 
the  females  of  some  animals,  as  the  sow,  phea- 
sant, and  pea-hen,  and  even  the  human  species, 
when  the  period  of  life  for  propagation  is 
passed,  assume  some  of  the  male  characteris- 
tics, such  as  the  plumage  in  the  birds  men- 
tioned, bristles  in  the  sow,  &c. 

It  is  well  known  that  the  annual  change  of 
the  horns  in  deer  is  intimately  connected  With 
the  generative  function.  Mr.  J.  Hunter  first 
shewed  by  experiment  that  when  the  deer  are 
castrated  while  the  horns  are  complete,  they 
remain  permanently  and  are  not  changed  as  in 
the  natural  condition  ;  and  that,  if  the  opera- 
tion be  performed  when  the  horns  have  fallen, 
they  will  not  again  be  renewed. 

The  operation  of  castration,  particularly  when 
it  is  not  performed  till  late  in  life,  while  it  pro- 
duces complete  sterility  in  the  female  and  im- 
potence in  the  male,  does  not  entirely  destroy 
sexual  desire,  for  eunuchs  and  the  castrated 
males  of  many  animals  are  known  to  be  lasci- 
vious. Some  writers  would  even  have  us  believe 
that  it  is  possible  for  the  power  of  propagation 


to  remain  in  the  male  after  castration.  These 
cases  appear  extremely  doubtful,  and,  even  ad- 
mitting the  truth  of  the  statement  that  a  cas- 
trated male  has  propagated,  this  by  no  means 
invalidates  the  statement  that  the  removal  of 
the  testicles  has  destroyed  all  productive  power, 
because  it  is  possible  that  some  seminal  fluid 
may  have  been  retained  in  the  seminal  vesicles 
and  vasa  deferentia.  The  operation  does  not 
prevent  the  erection  of  the  penis  or  venereal 
orgasm  from  taking  place ;  consequently  the 
act  of  sexual  union,  and  even  some  emission  of 
fluid  from  the  vesiculae  seminales  and  prostatic 
body,  may  occur  in  the  castrated  animal ;  and 
in  some  kinds  of  animals,  it  may  further  be  re- 
marked, that  the  union  of  such  males  with  the 
females,  though  altogether  unproductive,  is 
attended  with  several  of  the  more  important 
changes  which  belong  to  fruitful  sexual  union, 
such  as  the  excitement  of  the  internal  organs  of 
the  female,  the  discharge  of  vesicles  from  the 
ovary,  and  the  formation  of  corpora  lutea. 

The  removal  of  one  testicle  or  ovary  only 
does  not  appear  to  be  attended  with  any  change 
in  the  sexual  or  other  functions  ;  and  it  appears 
to  be  equally  inconsistent  with  fact,  that  those 
originally  provided  with  only  one  of  these 
essential  organs,  are  endowed  with  less  procrea- 
tive  power  than  others,  as  that  those  who  are 
said  to  have  had  more  than  the  usual  number 
are  remarkably  salacious  or  fertile. 

3.  Sexual  feeling. — In  all  animals  in  which 
the  distinction  of  sex  exists,  the  first  act  of  the 
generative  process  or  the  union  of  the  sexes  is 
insured  by  instinctive  feelings  experienced  by 
both  of  them  in  a  greater  or  less  degree. 
These  feelings  generally  depend  upon  the  con- 
dition of  the  body,  and  in  particular  of  the 
genital  organs,  which  at  the  time  of  pro- 
pagation are  in  a  greater  than  ordinary  state 
of  excitement.  From  the  increase  of  peculiar 
secretions,  at  the  breeding  season,  the  odour  of 
the  genital  organs  of  animals  becomes  stronger 
than  at  other  times,  and  seems  to  have  a  very 
direct  effect  in  exciting  the  sexual  appetite. 
These  feelings  are  in  the  greater  number  of 
animals  strongest  in  the  male,  and  he  conse- 
quently generally  seeks  the  retiring  female ; 
but  in  other  instances  the  reverse  is  the  case. 

In  the  human  species  also,  similar  feelings 
exist,  but  under  the  control  of  the  intellectual 
and  moral  powers  of  the  mind.  Hence  the 
immense  variety  we  observe  in  the  effects  of  the 
exercise  of  the  sexual  passions  on  different  peo- 
ple, and  hence  the  various  modifications  which 
they  undergo  from  the  state  of  civilization 
among  different  nations;  on  the  one  hand 
being  productive  of  scenes  and  habits  of  dis- 
gusting obscenity  among  those  barbarous  peo- 
ple whose  propensities  are  unrestrained  by 
mental  cultivation  ;  and  on  the  other,  attended 
by  social  ties  and  higher  intellectual  ideas 
among  those  in  whom,  from  education  and  the 
cultivation  of  the  mind,  the  bodily  appetites  or 
passions,  subject  to  the  reason,  assume  a  milder, 
less  selfish,  and  more  elevated  character.  Hence 
it  comes  that  the  various  customs  of  different 
nations,  legislative  enactments  of  ancient  and 
modern  statesmen,  and  even  some  religious  in- 

2  o  '2 


444 


GENERATION. 


junctions  and  ceremonies  relating  to  marriage 
and  concubinage,  are  to  be  regarded  rather  as  a 
picture  of  the  state  of  civilization  among  the 
different  people  to  which  they  have  belonged, 
and  as  the  result  of  local  situation  and  circum- 
stances, than  a  consequence  of  their  physical 
organization  or  natural  endowments,  as  some 
would  have  us  to  believe.  But  the  considera- 
tion of  these  modifications  in  the  customs  and 
habits  of  different  nations  belongs  more  appro- 
priately to  the  province  of  the  political  econo- 
mist than  of  the  physiologist. 

4.  Kelution  of  reproduction  to  the  brain. — 
In  how  far  the  sexual  feelings  just  spoken  of, 
and  the  reproductive  function  as  a  whole,  are 
connected  with  the  brain  or  any  of  its  parts,  we 
leave  to  be  discussed  by  others.  We  shall  only 
remark  in  this  place  respecting  this  connection, 
that  the  mental  feeling  and  local  affection  rela- 
ting to  sex  are  very  intimately  associated  toge- 
ther; on  the  one  hand,  the  local  irritation  of 
the  genital  organs  exciting  mental  desire,  and 
on  the  other,  the  erection  and  other  signs  of 
affection  of  the  sexual  organs  being  immediately 
caused  by  all  those  ideas  and  passions  of  the 
mind  which  bear  a  relation  to  sex.  In  the 
same  manner  as  the  action  of  the  heart,  the  flow 
of  the  blood  in  some  of  the  bloodvessels,  the 
processes  of  digestion,  respiration,  and  secre- 
tion are  modified  by  mental  emotions,  the  sexual 
function  may  be  regarded  as  subject  to  their 
influence,  and  consequently  subject  to  modifi- 
cation from  the  condition  of  the  mind  or  brain. 

In  the  phrenological  system,  as  is  well 
known,  it  is  held  that  the  cerebellum  is 
that  particular  part  of  the  encephalon  which 
presides  over  the  sexual  function, — in  other 
words,  that  sexual  feeling  belongs  to  the  cere- 
bellum as  its  sensorium  commune,  to  which 
impressions  of  a  sexual  kind  proceed,  and  from 
which  emanates  sexual  desire,  as  well  as  the 
influence  under  which  the  reproductive  organs 
execute  their  appropriate  functions.  The  proofs 
alleged  in  favour  of  the  phrenological  hypothesis 
are  principally  of  the  following  kind  :  1st,  that 
the  back  of  the  head  and  neck,  and  particularly 
the  cerebellum,  is  largest  in  those  of  the  human 
species  who  shew  much  sexual  love,  and  among 
animals  in  those  in  which  sexual  feeling  and 
productive  power  are  greatest ;  2d,  that  local 
affections  of  the  genital  organs,  and  variations  in 
the  degree  of  sexual  desire,  frequently  coincide 
with  congenital  deviations  from  the  natural 
form  and  structure  of  the  cerebellum,  and 
morbid  organic  changes  of  that  organ,  such 
as  inflammation,  suppuration,  effusion,  tu- 
mours, and  softening,  or  violent  injuries,  such 
as  wounds  producing  the  destruction  or  re- 
moval of  portions  of  the  same  part  of  the 
brain.*  We  leave  to  others  the  examination 
of  the  truth  of  this  view,  observing  merely 
that  we  are  not  inclined  to  adopt  the  hypo- 

*  The  proofs  of  the  connection  of  the  cerebellum 
with  the  sexual  function  may  be  more  fully  stated 
as  follows : 

1st.  The  coincidence  of  barrenness  or  impotence 
with  hydrocephalus,  ramollissement,  suppuration, 
or  wounds  of  the  head,  and  in  particular  of  the 
back  part  and  cerebellum. 


thesis  as  already  established  upon  sufficiently 
accurate  or  extensive  data ;  and  we  would  re- 
mark that  the  comparative  anatomy  of  the 
brain  (in  which,  rather  than  in  experiments  on 
animals,  we  should  feel  disposed  to  place  much 
reliance,  from  the  acknowledged  difficulty 
of  making  correct  deductions  as  to  function 
from  the  effects  of  morbid  alteration  or  artificial 
injury  of  the  encephalon)  affords  very  few  argu- 
ments in  favour  of  the  view  now  alluded  to,  and 
furnishes  several  facts  which  militate  strongly 
against  it. 

5.  Distinction  of  species.  Mules. — The  in- 
stinctive feelings  which  lead  to  the  union  of 
male  and  female  animals  of  the  same  species 
may  be  looked  upon  as  one  of  the  means  pro- 
vided by  nature  for  the  distinct  preservation  of 
each  specific  race.  So  general  indeed  is  the 
law  that  animals  of  one  species  propagate  with 
one  another  only,  that,  as  we  already  remarked, 
this  circumstance  alone  has  been  adopted  by 
some  as  the  true  specific  character.  We  shall 
see  reason,  however,  to  doubt  its  sufficiency. 

While  the  natural  repugnance  which  the 
males  and  females  of  different  species  or 
genera  have  to  propagate  together  may  be 
regarded  as  one  of  the  most  powerful  means 
by  which  the  distinction  of  species  is  insured, 
we  must  not  lose  sight  of  other  circumstan- 
ces which  contribute  to  the  same  effect. 
Among  these  may  be  mentioned,  in  the  first 
place,  the  unfruitfulness  which  generally  attends 
the  union  of  different  species  when  it  has  oc- 
curred ;  then  the  difference  in  the  size  of  ani- 
mals, the  discordant  properties  of  the  semen  of 
the  one  and  ova  of  the  other,  the  difference  of 
season  at  which  nearly  allied  animals  come 
into  heat,  as  well  as  many  other  circumstances 
which  put  a  bar  to  the  extension  of  races  by 
promiscuous  propagation  of  species  or  genera. 

In  the  state  of  domesticity,  however,  this, 

2d.  The  coincidence  of  excited  states  of  the  re- 
productive organs,  as  priapism,  nymphomania,  and 
satyriasis,  with  inflammation  of  the  same  parts. 

3d.  Instances  occurring  in  birds  (mentioned  by 
Serres)  of  cerebellar  apoplexy  from  the  persistence 
of  unsatisfied  sexual  desire. 

4th.  Coincidence  of  cerebellar  apoplexy,  inflam- 
mation, &c.  and  diminution  of  the  sensorial  power, 
with  over-exertion  of  the  sexual  powers,  excess  in 
venereal  pleasures,  &c. 

5th.  Large  size  of  the  cerebellum  or  upper  and 
back  part  of  the  neck  in  those  individuals  among 
the  human  species  or  among  animals  in  which  the 
sexual  desire  and  reproductive  power  are  greatest, 

6th.  The  reverse  being  the  case  in  those  in  whom 
the  function  is  inactive ;  as  the  small  size  of  the 
back  of  the  neck,  &c.  in  castrated  animals. 

In  endeavouring  to  ascertain  the  value  of  this 
kind  of  evidence  adduced  in  favour  of  the  phrenolo- 
gical view,  we  must  consider  well  the  nature  of  the 
alleged  facts  themselves,  and  weigh  them  candidly 
against  facts  of  an  opposite  tendency  adduced  on 
the  other  side,  such  as  those  cases  of  small  size  or 
absence  of  the  cerebellum,  in  which  the  sexual 
propensities  have  been  highly  developed,  and  the 
converse  cases  ;  and  we  must,  at  the  same  time, 
not  lose  sight  of  those  other  experiments  and  obser- 
vations which  would  tend  to  shew  either  that  the 
cerebellum  is  intimately  connected  with  other  func- 
tions than  the  reproductive,  or  that  the  sexual 
powers  are  influenced  by  the  condition  of  other  parts 
of  the  brain  besides  the  cerebellum. 


GENERATION. 


4-15 


like  other  laws  of  the  reproductive  function,  is 
subject  to  some  modification,  and  we  find  ac- 
cordingly several  allied  species  of  the  domestic 
animals  breeding  freely  together  ;  and  there  are 
not  wanting,  even  in  the  wild  state,  examples 
of  the  mixture  of  distinct  species. 

The  animal  produced  by  the  union  of  the 
male  and  female  of  distinct  species  receives 
the  name  of  Hybrid  or  Mule,  which  generally 
partakes  of  the  qualities  of  both  its  parents  in 
a  greater  or  less  degree.  Here  again  we  find 
another  effectual  impediment  put  by  nature  to 
the  mixture  of  different  species,  in  this  circum- 
stance, that  the  mule,  whether  male  or  female, 
is  usually  unfit  for  propagation.  The  offspring 
of  male  and  female  of  distinct  species  is  much 
more  frequently  fruitful  than  that  of  distinct 
genera.*  The  instances  of  the  former  are  not 
few,  as  in  the  wild  and  tame  cat,  the  wild 
boar  and  domestic  hog,  the  pheasant  and 
domestic  fowl,  the  wild  and  tame  duck. 
But  the  instances  of  the  latter  or  mixture  of 
distinct  genera  are  very  rare,  and  most  of  them 
require  confirmation.  We  must  at  the  same 
time  always  hold  in  mind  that  the  distinction  of 
species  by  naturalists  is  at  all  times  artificial  or 
made  by  man,  how  much  soever  he  may  con- 
ceive his  classification  to  be  founded  in  nature, 
and  those  animals  which  are  regarded  by  one 
naturalist  as  different  species  of  the  same 
genus  are  made  by  others  to  constitute  distinct 
genera. 

It  is  well  known  that  in  gardens  and  else- 
where, although  the  pollen  of  very  various 
plants  is  almost  constantly  flying  about  through 
the  air,  it  is  only  among  the  most  nearly  allied 
races  or  varieties  that  mixture  occurs,  and  the 
instances  of  the  mixture  of  different  species  of 
plants  are  very  rare  indeed.  Many  of  the 
mixed  varieties  so  produced  cannot  be  pro- 
pagated by  seeds  ;  so  that  there  is  in  the  vege- 
table as  well  as  in  the  animal  kingdom  a  con- 
stant tendency  to  return  to  the  original  distinct 
species. 

The  milt  and  spawn  of  different  fishes  are  at 

*  The  following  examples  of  the  mixture  of 
species  are  given  by  Hurdach,  but  some  of  them 


require  confirmation. 

Papilio  J urtina  unites  with 

P.  Jurtina. 

Chrysornela  JEnea. 

C.  Alni. 

PhalangiumCornutum 

P.  Opulio. 

Cyprinus  Carpio  ,, 

C.  CarassiusorGibelio. 

FringilU  Carnuelis 

F.  Canaria. 

Phasianus  Gallus 

P.  Colchicus. 

Anas  Olor 

A.  Anser. 

Anas  Glaucion 

A .  Querquedula. 

Tetrao  Tetrix  „ 

T.  Urogal'us. 

Corvus  Corone  ,, 

C.  Cornix. 

Canis  Familiaris 

C.  Lupus. 

Canis  Familiaris 

C.  Vulpes. 

Equus  Caballus  „ 

E.  Zebra. 

Equus  Caballus  „ 

E.  A  sinus. 

Equus  Zebra 

E.  A  sinus. 

Equus  Caballus 

E.  Quagga. 

Capra  Hircus 

C.  Ibex. 

The   examples   of  genera 

breeding  together  are 

much  less  numerous. 

Rana 

Bufo. 

Tetrao  Tetrix               , , 

Phasianus  Colchicus. 

Capra  Hircus 

Aniilope  Rupicapra. 

Cervus  Elaphus 

15os  Taurus  ? 

Cetvus  Elapus 

Ovis  Aries. 

the  same  time  floating  in  the  same  water,  but 
even  thus  brought  into  close  union  with  one 
another,  no  mixture  happens.  The  ingenious 
experiments  of  the  celebrated  Spallanzani, 
who  attempted  to  impregnate  artificially  the 
ova  of  one  animal  with  the  seminal  fluid 
of  another,  and  the  unsuccessful  attempts  of 
many  to  cause  different  animals  to  breed  toge- 
ther, afford  still  farther  proofs,  were  they  want- 
ing, of  the  number  and  completeness  of  the 
impediments  which  nature  has  opposed  to  the 
promiscuous  breeding  of  distinct  species. 

The  horse  and  ass  are  caused,  it  is  known, 
to  unite  by  man,  and  do  not  naturally  do  so; 
and  in  the  wild  state  it  is  probable  that  the 
exceptions  to  the  general  rule  before-mentioned 
occur  only  when  the  male  is  deprived  of  his 
natural  female.  It  seems  scarcely  necessary 
to  state  that  the  stories  of  fruitful  union  of 
either  male  or  female  of  the  human  species 
with  apes  or  other  animals,  considered  as  au- 
thentic by  some  authors,  are  entirely  fabu- 
lous. 

In  a  subsequent  part  of  this  article  we  shall 
have  occasion  to  revert  to  the  subject  of  the 
mixture  of  races  in  our  remarks  upon  the 
transmission  of  the  qualities  of  the  parent  to 
the  offspring. 

6.  Functions  of  the  external  organs  of  re- 
production.— In  addition  to  sexual  feelings, 
the  state  of  turgescence  or  erection  of  the  ex- 
ternal organs  by  which  copulation  is  effected, 
is  a  more  or  less  constant  antecedent  and 
concomitant  of  the  first  act  of  the  generative 
process.  This  condition  belongs  more  pro- 
perly to  the  external  sexual  organs  of  the  male, 
and  especially  the  penis;  but  it  also  frequently 
exists  in  some  parts  of  the  female  organs. 

The  erection  of  the  penis  producing  the 
rigidity  of  that  organ  necessary  to  ensure  eja- 
culation or  forcible  emission  of  the  seminal 
fluid,  consists  essentially  in  the  increased 
quantity  of  fluid  in  its  bloodvessels,  and  is 
with  most  reason  to  be  attributed  chiefly  to  the 
peculiar  structure  and  inherent  properties  of 
the  tissue,  so  called  erectile,  of  which  it  is 
mainly  formed.  The  manner  in  which  the 
greater  accumulation  of  blood  in  the  erectile 
tissue  is  brought  about  is  by  no  means  suf- 
ficiently clearly  explained.  Two  different 
opinions  prevail  as  to  the  cause  of  this  phe- 
nomenon ;  the  one,  that  the  flow  of  blood  is 
retarded  in  the  veins  by  the  contraction  and 
consequent  pressure  of  certain  muscles  situ- 
ated towards  the  root  of  the  penis ;  the  other, 
that  the  turgescence  of  erection  is  caused  by 
an  altered  action  or  condition  of  the  blood- 
vessels themselves,  peculiar  to  the  erectile 
tissue,  in  which  they  are  capable  of  admitting 
and  retaining  a  greater  quantity  of  blood  in 
the  erected  than  in  the  collapsed  state. 

We  must  refer  to  the  various  anatomical 
articles  for  an  account  of  the  structure  of  the 
erectile  tissue  and  the  organs  in  which  it  occurs  ; 
we  shall  in  this  place  advert  to  those  points 
only  which  seem  to  bear  upon  the  physiological 
view  of  their  function. 

The  glans  penis,  corpus  spongiosum  urethra;, 
and  corpora  cavernosa  penis,  consist  in  great 


446 


GENERATION. 


part  of  largely  convoluted  veins  of  conside- 
rable size ;  but  these  veins  are  differently  ar- 
ranged in  the  last-mentioned  of  these  parts 
from  what  they  are  in  the  two  first :  first  in 
this  respect,  that  in  the  glans  and  corpus  spon- 
giosum urethra  the  tortuous  veins  are  less 
dilated  and  more  branched  than  in  the  corpora 
cavernosa;  so  that  it  is  more  easy  to  trace  their 
continuity  with  one  another;  and,  second,  that 
in  the  corpora  cavernosa  the  dilated  veins  are 
bound  together  and  crossed  in  various  direc- 
tions by  ligamentous  fibres  and  bands, — an 
arrangement  which,  while  it  tends  to  obscure 
the  connection  of  one  vein  with  another,  and 
causes  their  tortuosities  to  appear  rather  like 
cells  than  continuous  tubes,  at  the  same  time 
serves  to  prevent  their  distension  beyond  a 
certain  point  during  erection,  and  thus  adds 
to  the  rigidity  occasioned  by  the  accumu- 
lation of  blood  in  the  venous  convolutions  or 
sinuses. 

The  mode  of  union  of  the  arteries  with  the 
veins  in  the  erectile  tissue  of  the  penis  is  not 
yet  well  known ;  for,  although  the  arteries  of 
the  penis  have  been  traced  to  very  small  rami- 
fications, corresponding  small  branches  of  the 
veins  have  not  been  observed,  and  conse- 
quently anatomists  are  nearly  in  complete  ig- 
norance of  the  nature  of  the  small  vessels  of 
communication  or  capillaries  of  the  erectile 
tissue,  and  are  left,  to  conjecture  only  respect- 
ing the  means  of  passage  for  the  blood  from 
the  small  arteries  into  the  cells  formed  by  the 
convoluted  veins.  Professor  Miiller,  of  Berlin,* 
has  lately  made  an  important  step  in  the  in- 
vestigation of  this  point  of  structure,  by  the 
discovery  of  a  remarkable  set  of  little  dilated 
and  ramified  branches  appended  to  the  termi- 
nal twigs  of  the  arteries  distributed  on  the 
sides  and  interspaces  of  the  venous  cavities 
in  the  penis  of  man  and  several  animals; 
but  so  tar  as  we  are  aware,  the  exact  mode 
of  nassage  of  the  blood  from  these  helicine 
arteues,  as  they  have  been  termed  from  their 
tortuosity,  has  not  been  detected,  and  the 
operation  of  these  arterial  branches  in  modi- 
fying the  circulation,  or  their  relation  to  the 
process  of  erection,  has  not  been  pointed  out; 
it  appears  probable  that  so  peculiar  a  piece  of 
mechanism  must  have  some  connection  with 
this  process.  (See  Erectile  TissuEand  Pen  is; 
also  Figs.  98  and  99,  p.  146,  vol.  ii.) 

The  principal  exciting  causes  of  erection 
may  be  referred  to  the  following  heads : — 

1.  Mental  emotions  relating  to  sex :  in  ani- 
mals, odour  of  the  genital  organs,  more  espe- 
cially in  the  breeding  season. 

2.  Nervous  affections.  Epilepsy,  convul- 
sions. Inflammations  of  the  brain,  and  simi- 
lar affections. 

3.  Warmth  or  other  local  irritation  of  the 
penis  and  sexual  organs. 

4.  A  full  state  of  the  testicles,  their  excre- 
tory ducts  or  vesiculse  seminales. 

*  See  his  Archiv.  fur  Physiol.  &c.  1835,  pp.  27 
and  220,  and  his  paper,  "  Ueber  die  organiscben 
Nerven  der  erectilen  mannlichen  Geschlectsor- 
gane,"  in  the  Abhand.  d.  k.  Akad.  d.  Wissensch. 
v.  Berlin  fur  1835. 


5.  Irritation  of  the  parts  in  the  vicinity  of 
the  penis,  as  of  the  urinary  bladder  by  stone, 
riding,  cantharides,  savine,  alcohol,  &c;  of  the 
rectum  by  strong  purgatives ;  and,  in  short, 
every  thing  which  irritates  or  determines  a 
greater  than  usual  flow  of  blood  to  the  pelvic 
viscera  or  sexual  organs. 

6.  Ligatures,  and  all  other  causes  of  ob- 
struction to  the  return  of  blood  from  the 
penis. 

Erection  is  an  involuntary  act;  for  we  have 
neither  the  power  directly  to  produce  it,  nor, 
when  it  occurs,  to  recall  the  state  of  collapse. 
When  the  penis  is  in  the  state  of  erection, 
however,  the  rigidity  may  be  increased  by  the 
voluntary  exertion  of  the  ischio-cavernosi  or 
erectores  penis,  and  the  acceleratores  urinae 
muscles ;  and  no  doubt  also  by  the  action  of 
the  muscles  lately  described  by  Dr.  Houston* 
under  the  name  of  compressores  vena  dorsalis 
penis,  to  the  contraction  of  which,  and  the 
consequent  impediment  produced  to  the  return 
of  blood  from  the  penis,  that  anatomist  has 
attributed  in  a  great  measure  the  erection  of 
the  organ. 

The  turgescence  of  erection  begins  at  the 
root  of  the  penis  in  the  corpora  cavernosa,  and 
at  the  glans  in  the  corpus  spongiosum.  The 
glans  and  spongy  body  of  the  urethra  may, 
in  general,  be  made  to  collapse  by  pressure, 
but  the  corpora  cavernosa  cannot  unless  the 
erectile  action  itself  ceases.  The  arteries  of 
the  penis  appear  to  beat  with  more  than  usual 
force  during  erection. 

The  phenomenon  of  erection  is  not  confined 
to  the  penis  or  such  parts  as  are  provided  with 
muscles,  but  occurs  in  all  situations  where 
that  arrangement  of  the  bloodvessels  consti- 
tuting the  erectile  tissue  is  to  be  found.  The 
nipple  of  the  mamma,  the  cock's  comb  and 
wattles,  and  the  turkey's  neck  are  all  affected 
in  a  similar  way ;  and,  although  some  circum- 
stances seem  to  shew  that  erection  may  in 
some  instances  be  promoted  by  muscular  con- 
traction, we  are  inclined  to  adopt  the  opinion 
that  it  is  mainly  due  to  an  altered  condition 
of  the  bloodvessels  themselves,  and  that  it 
may  in  some  degree  be  analogous  to  the  dila- 
tation of  the  bloodvessels  which  occurs  in 
blushing,  and  some  other  local  determinations 
of  blood. f  The  large  size  of  the  numerous 
nerves  which  accompany  the  bloodvessels  of 
the  penis  is  also  in  favour  of  this  view. 

In  many  animals  the  penis  is  furnished  with 
a  bone  which  adds  to  its  rigidity.  This  is  the 
case  chiefly  among  Cheiroptera,  Quadrumana, 
Solipeda,  Digitigrada,  Rodentia,  Phoca,  and 
Cetacea.  We  refer  to  the  articles  on  Com- 
parative Anatomy  for  a  description  of  the  many 
varieties  in  the  form  of  the  penis  in  different 
animals,  and  their  uses  in  the  act  of  propa- 
gation. 

The  texture  of  which  the  glans  clitoridis 
and  corpora  cavernosa  of  that  body  as  well  as 
the  nymphae  are  formed,  is  of  an  erectile  kind 
and  strictly  analogous   to  the  corresponding 

*  Dublin  Hospital  Reports,  vol.  v. 

t  See  the  article  Circulation,  vol.  i.  p.672. 


GENERATION. 


447 


parts*  of  the  penis,  to  which  the  clitoris  bears 
a  great  similarity ;  and  it  may  be  remarked 
that  there  is  also  a  functional  analogy,  as  these 
parts  in  the  female  sometimes  undergo  the 
change  of  erection  under  local  irritation  or 
venereal  excitement. 

The  glans  penis  is  endowed  with  a  high 
degree  of  sensibility,  and  is  regarded  generally 
as  the  chief  seat  of  venereal  pleasure  ;  but  this 
also  belongs  to  the  urethra  at  the  time  of 
emission.  The  papillous  structure  of  the 
mucous  membrane  covering  the  glans,  and  the 
large  quantity  of  nerves  distributed  on  its 
surface,  relate  to  this  high  sensory  endow- 
ment. 

The  lower  part  of  the  vagina  and  the  clitoris 
in  particular  are  possessed  of  a  similar  high 
degree  of  sensibility,  and  in  some  women,  but 
not  in  all,  are  the  seat  of  venereal  feelings  from 
excitement ;  but  in  many  women  such  feelings 
are  altogether  absent ;  and  it  is  most  erroneous 
to  suppose,  as  some  have  done,  that  these 
feelings  are  in  either  sex  necessary  to  insure  the 
fecundating  power  of  the  one,  or  the  liability 
to  conception  of  the  other. 

With  regard  to  the  uses  of  the  hymen  we 
have  no  conjecture  to  offer. 

The  vagina,  besides  serving  to  receive  the 
penis  in  copulation  and  to  conduct  the  seminal 
fluid  to  the  uterus,  is  the  passage  by  which  the 
child  issues  in  parturition. 

IV.   CHANGES  CONSEQUENT  ON  FRUITFUL 
SEXUAL  UNION. 

1.  As  regards  the  female  chiefly.  Concep- 
tion.— The  consequence  of  fruitful  sexual  union 
in  man  and  quadrupeds  is  the  dislodgement  of 
one  of  the  ova  contained  in  the  ovarium,  and 
the  fecundation  of  this  ovum  in  some  part  of 
its  passage  from  the  ovarium,  where  it  is  formed, 
to  the  uterus,  in  which  the  foetus  is  developed 
from  it. 

In  now  proceeding  to  treat  of  the  mode  in 
which  these  further  steps  of  the  generative  pro- 
cess are  brought  about,  the  following  subjects 
present  themselves  for  our  consideration.  1st. 
What  changes  are  operated  in  the  internal 
female  organs  after  fruitful  sexual  union,  and 
by  what  means  are  the  ova  dislodged  from  the 
ovary?  2d.  What  changes  do  the  ovaries  or 
their  vesicles  undergo  after  the  discharge  of  any 
of  the  ova  ?  3d.  What  happens  to  the  ovum 
from  the  time  of  its  discharge  from  the  ovary 
until  the  commencement  of  the  development  of 
the  foetus?  4th.  In  what  part  of  the  female  ge- 
nerative system  is  the  change  of  fecundation 
effected  by  the  agency  of  the  seminal  fluid  upon 
the  germinal  part  of  the  egg?  and  lastly,  In 
what  does  the  change  of  fecundation  consist,  or 
upon  what  properties  of  the  seminal  fluid  may 
it  be  supposed  to  depend  ? 

These  topics  comprehend  the  history  of  the 
functions  of  the  male  and  female  internal  gene- 

*  The  glans  penis  and  glans  clitoridis,  the  nym- 
pha;  and  corpus  spongiosum  urethra;,  and  the  cor- 
pora cavernosa  penis  and  clitoridis  are  considered 
anatomically  as  the  respective  corresponding  parts 
in  the  male  and  female  body. 


rative  organs,  in  so  far  as  they  relate  to  the  pro- 
cesses of  conception  and  fecundation  ;  under 
which  two  heads,  as  has  been  already  men- 
tioned, it  is  our  intention  to  bring  the  remainder 
of  the  facts  respecting  generation  which  come 
within  the  limits  of  the  present  article.  We 
shall  begin  with  those  facts  relating  chiefly  to 
the  female,  or  conception. 

The  immediate  consequence  of  sexual  union 
upon  the  female  internal  generative  organs  is 
their  great  excitement,  and  a  turgescence  pro- 
duced by  an  accumulation  of  blood  in  their 
vessels.  When  sexual  union  proves  productive, 
this  turgescence  lasts  for  some  time  after  it  has 
taken  place,  so  that  in  animals  opened  at  this 
time,  the  ovaries,  Fallopian  tubes,  and  uterus 
are  found  to  be  of  a  much  deeper  red  colour, 
and  more  vascular  than  in  their  natural  state. 
In  the  female  Rabbit,  for  example,  opened 
soon  after  coition,  the  internal  organs  are  nearly 
black  from  sanguineous  congestion. 

There  also  occurs  in  some  of  these  parts  a 
change  of  position  in  regard  to  one  another, 
which  is  connected  with  the  discharge  of  ova 
from  the  ovarian  vesicles.  The  fimbriated  ex- 
tremities of  the  Fallopian  tubes  are  turned  to- 
wards the  ovaries  on  each  side,  and  embrace 
these  organs  closely,  so  that  the  infundibular 
opening  is  applied  against  the  ovary,  and  must 
of  necessity  receive  the  contents  of  the  Graafian 
vesicle  when  it  bursts.  In  some  animals  the 
ovary  is  inclosed  in  a  sac  along  with  the  infun- 
dibulum  by  a  reduplication  of  the  peritoneum, 
so  that  the  ovary  is  kept  always  to  a  certain 
extent  within  the  infundibulum ;  but  in  other 
animals  in  which  the  connection  between  these 
parts  is  not  of  this  permanent  kind,  there  is  an 
equally  firm  union  of  them  after  copulation. 
In  regard  to  the  means  by  which  this  approxi- 
mation and  union  of  the  fimbriae  and  ovaries 
are  brought  about,  it  may  be  stated,  that  in 
some  animals  the  action  seems  to  be  somewhat 
of  a  muscular  kind  ;  for  there  are  strong  fibres, 
having  all  the  appearance  of  muscular,  fibres, 
which  pass  from  the  ovary  towards  the  fimbri- 
ated portion  of  the  Fallopian  tube ;  and  in 
these  animals,  as  well  as  in  others  even,  in 
which  the  muscular  fibres  are  less  obvious,  irri- 
table contraction  may  be  supposed  to  be  a 
means  of  bringing  the  parts  nearer  to  one 
another.  The  observations  of  Hartsoeker  and 
Haller,  however,  would  appear  to  shew  that 
the  vascular  turgescence  which  follows  co- 
pulation, amounting  to  a  state  approaching 
to  erection,  may  also  contribute  to  give  rise 
to  the  change  of  position  now  under  consi- 
deration, for  they  found  by  repeated  trials 
that  the  forcible  injection  of  fluids  into  the 
bloodvessels  of  the  generative  organs  in 
the  human  dead  body  caused  the  approxi- 
mation of  the  fimbriaB  and  ovaries.  But, 
although  it  may  be  admitted  that  vascular  tur- 
gescence may  cause  this  approximation  of  the 
parts,  we  would  venture  to  suggest  that  some 
power  of  the  nature  of  muscular  contraction  is 
necessary  to  give  that  degree  of  firmness  to  the 
union  which  it  is  found  to  possess  some  time 
after  copulation. 

We  must  remark,  however,  that  when  a 


448 


GENERATION. 


female  quadruped  is  opened  immediately  after 
copulation,  the  fimbriae  are  frequently  not 
observed  to  be  in  contact  with  the  ovary ; 
and  this  is  found  to  be  the  case  only  when 
some  hours  are  allowed  to  elapse  between 
the  copulation  and  the  death  of  the  animal. 
Haighton  never  found  it  to  have  taken  place 
in  the  rabbit  previous  to  nine  hours  after  union 
with  the  male,  and  De  Graaf  not  even  before 
twenty-seven  hours  ;  but  observations  of  this 
nature  upon  animals  opened  soon  after  being 
lulled,  do  not  make  it  certain  that  the  action 
had  not  taken  place ;  for  it  may  be  supposed 
that  the  adhesion  between  the  infundibula 
and  ovaries  had  commenced,  but  was  less  firm 
than  it  becomes  at  a  subsequent  period,  and 
that  it  was  merely  disturbed  by  the  violence 
of  the  death  or  rough  handling  of  the  body. 
This  is  the  more  probable,  seeing  that  the 
same  change  of  position  has  been  observed  to 
take  place  before  sexual  union  in  animals  in 
the  state  of  heat,  as  by  Cruikshank  in  the  rab- 
bit, and  by  Haller  in  the  sheep.  In  some 
birds,  particularly  domestic  fowls  and  ducks,  it 
is  well  known  that  when  they  are  well  fed  all 
the  changes  necessary  for  the  formation  of  an 
ovum  and  its  discharge  from  the  ovary  may  take 
place  without  the  concurrence  of  the  male,  and 
in  quadrupeds  there  is  reason  to  believe  that 
the  turgescence  and  change  of  position  of  the 
generative  organs  above  alluded  to  may  fre- 
quently occur  independently  of  fruitful  or  un- 
fruitful sexual  union,  as  from  excitement  of  the 
generative  organs  in  the  state  of  heat,  or  as  in 
the  cases  observed  by  Mailer,  of  ewes  having 
connection  with  wedders  or  castrated  males 
only. 

There  is  every  reason  to  suppose  that  the 
same  changes  which  we  have  described  as  oc- 
curring in  quadrupeds  after  sexual  union,  take 
place  in  the  same  circumstances  in  the  human 
female;  that  is,  that  the  fimbriated  infundibula 
of  the  Fallopian  tubes  are  brought  near  to  the 
ovaries,  and  are  made  to  embrace  them  firmly, 
so  as  te-  receive  the  contents  of  any  vesicles 
which  may  burst;  and  that  this  change  is 
produced  by  an  action  which  begins  usually 
during  sexual  union,  but  which  may  also  occur 
without  any  venereal  orgasm. 

The  ovaries,  we  have  already  stated,  become 
unusually  vascular  during  and  after  sexual 
union  ;  but  the  changes  in  the  ovary  which 
most  demand  our  attention,  are  those  connected 
with  the  bursting  of  the  Graafian  vesicles,  and 
the  discharge  of  their  contents.  In  the  unim- 
pregnated  female  arrived  at  the  age  of  puberty, 
the  Graafian  vesicles  of  the  ovary  are  of  une- 
qual size.  Some  time  after  sexual  union,  one 
or  more  of  these  vesicles,  probably  those  which 
are  at  the  time  farthest  advanced,  undergoes  a 
greater  enlargement,  and  from  its  swelling  pro- 
jects beyond  the  rest  of  the  surface  of  the  ovary, 
and  after  various  other  changes,  an  aperture  is 
formed  in  the  most  projecting  part  of  the  coats 
of  the  vesicle,  through  which  its  contents  find 
an  issue.  But  before  proceeding  further  with 
this  narrative,  we  must  recall  to  the  recollection 
of  the  reader  the  nature  of  the  ovum,  which,  on 
the  occasion  of  the  rupture  of  one  of  the 


Graafian  vesicles,  is  discharged  from  its  inte- 
rior. 

The  ovarian  vesicles  of  man  and  quadrupeds 
are  tilled  with  fluid,  which,  viewed  by  the  un- 
assisted eye,  appears  to  contain  only  a  little 
granular  and  flaky  matter.  This  fluid  is  coa- 
gulated by  heat,  alcohol,  or  acids,  as  albumen 
is,  and  also  by  exposure  to  air.  The  membrane 
forming  the  vesicle  consists  of  two  layers,  an 
external  and  internal,  and  the  whole  vesicle  is 
covered  also  by  the  general  peritoneal  and  vas- 
cular envelope  of  the  ovary. 

From  the  earliest  times  anatomists  and  phy- 
siologists seem  to  have  considered  the  ovarian 
vesicles  as  the  source  of  the  offspring ;  and 
many,  from  a  sort  of  loose  analogy  with  ovipa- 
rous animals,  regarded  the  vesicles  themselves 
as  the  ova  in  which  the  viviparous  foetus  is  de- 
veloped. The  large  size  of  these  vesicles,  how- 
ever, as  compared  with  the  Fallopian  tubes 
through  which  the  ova  have  to  pass,  and  the 
subsequent  observations  of  De  Graaf,  Vallisneri, 
and  Cruikshank,  as  later  those  of  Prevost, 
Dumas,  and  others,  who  found  in  the  first  days 
after  copulation  ova  in  the  Fallopian  tubes  of 
a  size  considerably  less  than  the  vesicles  of  the 
ovary  from  which  they  had  proceeded,  proved 
satisfactorily  that  the  ovarian  vesicles  and  ova 
are  not  identical.  Various  conjectures  were  in 
the  meantime  offered  by  different  authors  as  to 
the  source  of  the  ovum ;  some  holding  it  to  be 
formed  by  a  process  of  secretion,  others  by 
an  organic  union  of  the  male  semen  with  the 
contents  of  the  Graafian  vesicle,  and  so  forth ; 
but  no  one  ever  observed  the  ovum  itself  of 
mammiferous  animals  within  the  ovary,  until 
Baer  made  this  important  discovery  in  1827, 
by  the  examination  with  the  microscope  of  the 
fluid  contents  of  the  Graafian  vesicle.* 

Baer  found  that,  in  the  centre  of  a  granular 
layer,  placed  generally  towards  the  most  promi- 
nent part  of  the  vesicle,  to  which  he  gives  the 
name  of  proligerous  disc  or  layer,  there  is  fixed 
a  very  minute  spheroid  body,  seldom  above 
s^th  part  of  an  inch  in  diameter.  The  appear- 
ance of  this  body  he  found  to  be  constant,  and 
on  examining  it  with  attention  in  the  vesicles 
of  the  ovaries,  and  after  their  rupture  in  the 
Fallopian  tubes,  he  traced  the  changes  it  un- 
derwent in  the  first  days  after  copulation,  and 
established  satisfactorily  the  identity  of  this 
body  with  the  ova  found  by  previous  observers 
in  the  Fallopian  tubes  and  cornua  of  the  uterus ; 
thus  proving  by  actual  observation  what  had 
before  been  held  only  from  analogy,  that  in  the 
mammiferous  or  truly  viviparous,  as  well  as  in 
the  oviparous  animal,  the  foetus  derives  its  origin 
from  an  ovum  already  formed  in  the  ovary 
before  fecundation. f 

*  Epistola  de  Ovi  Mammalium  et  Hominis 
Genesi.    Lipsiae,  1827. 

f  We  have  no  hesitation  in  giving  the  sole  and 
undivided  merit  of  this  discovery  to  the  indefatiga- 
ble and  talented  Baer,  whose  observations  have  con- 
tributed, perhaps  more  than  any  other  single  indivi- 
dual of  the  present  time,  to  extend  our  knowledge 
of  the  early  formation  of  the  foetus.  We  ought  not, 
however,  to  omit  to  mention  that  Messrs.  Prevost 
and  Dumas  conceived  that  in  two  instances  they 
had  perceived  ova  in  the  ovarian  vesicles  of  quad- 


GENERATION. 


449 


Some  time  after  sexual  union  the  fluid  con- 
tained in  the  vesicles  which  are  about  to  burst, 
previously  transparent  and  nearly  colourless, 
now  becomes  more  viscid  and  tenacious,  some- 
what turbid  and  of  a  reddish  colour ;  and  in 
some  animals  it  is  possible  in  such  ripe  vesicles 
to  perceive,  with  the  unassisted  eye  in  a  favour- 
able light,  a  whitish  opaque  spot  on  the  most 
prominent  part,  indicating  the  layer  of  granules 
or  proligerous  disc,  in  the  centre  of  which  the 
ovum  is  situated.  After  a  certain  time  a  small 
opening  is  formed  at  the  most  prominent  part 
of  the  coverings  of  the  vesicle,  the  vesicle  bursts, 
and  its  contents  escape  through  the  opening ; 
they  are  received  in  the  infundibulum,  which  is 
now  applied  firmly  against  the  ovary  ;  and  the 
ovum  entering  the  Fallopian  tube  is  conveyed 
along  it,  probably  by  its  slow  and  gradual  ver- 
micular contractions,  until  it  at  last  arrives  in 
the  uterus. 

With  regard  to  the  time  at  which  the  opening 
of  the  ovarian  vesicles  takes  place,  there  are 
considerable  varieties  in  the  same  and  in  diffe- 
rent animals.  In  the  sheep,  the  vesicle  has 
been  found  burst  so  early  as  at  two  hours  after 
coition.  In  the  dog,  Haller  found  the  vesicles 
burst  before  the  sixth  day  ;  in  one  instance  the 
day  after  coition  ;  but  Prevost  and  Dumas,  not 
until  the  seventh  or  eighth.  In  the  rabbit, 
Cruikshank  observed  vesicles  burst  two  hours 
after  coition,  while  Haighton  considers  forty- 
eight  hours  as  the  usual  time  at  which  the  rup- 
ture happens  in  this  animal.  M.  Coste  has 
observed  it  most  frequently  between  the  second 
and  third  day  in  the  rabbit. 

After  the  bursting  of  the  Graafian  vesicles, 
there  occur  in  them  and  in  the  neighbouring 
part  of  the  ovary  some  important  changes  of 
structure,  which  claim  our  attention  in  this 
place  as  intimately  connected  with  that  part  of 
the  process  of  conception  which  is  now  under 
consideration. 

If  the  Graafian  vesicle  which  is  enlarged 
from  venereal  excitement  and  is  ready  to  burst, 
be  examined  with  care,  it  will  be  seen  that  at 
the  most  prominent  part  of  its  coats  the  blood- 
vessels converge  towards  the  point  at  which 

rupeds,  (Annal.  d.  Scien.  Nat.  torn.  iii.  p.  135,) 
but  without  any  certainty  or  exact  knowledge  as  to 
their  nature.  M.  Coste,  with  a  spirit  of  appropria- 
tion too  common,  we  regret  to  say,  among  his  coun- 
trymen, has  taken  advantage  of  some  speculative 
views  ami  strained  analogies  brought  forward  by 
Baer  concerning  the  bodies  which  he  discovered,  in 
which  he  compared  them  (erroneously  as  we  think) 
to  the  germinal  part  only  of  the  ovum,  rather  than 
to  the  whole  ovum  of  the  oviparous  animal,  to  take 
from  the  merits  of  Baer  in  their  discovery  ;  but  we 
feel  assured  that  every  unprejudiced  inquirer  who 
reads  with  attention  Baer's  admirable  "  Epistola 
de  Ovi  Mammalium  et  Hominis  Genesi,"  in  which 
his  discovery  was  first  announced  in  1827,  and 
compares  it  with  other  works  on  the  subject, 
will  be  convinced  that  Baer  has  no  sharer  in  the 
discovery,  and  fully  understood  the  nature  of  the 
ovarian  ovum  of  viviparous  animals ;  although 
it  may  be  the  case  that  subsequent  investigations 
have  added  considerably  to  the  knowledge  of  the 
relations  of  these  ova.  We  shall  return  to  a  more 
minute  detail  of  this  body  in  considering  the  process 
of  formation  of  the  ovum  in  the  present  article  and 
under  the  article  Ovum. 


the  rupture  afterwards  takes  place,  and  this 
point  is  itself  comparatively  destitute  of  blood- 
vessels.* 

At  the  time  of  the  formation  of  the  opening 
into  the  vesicle,  from  the  division  of  some  of 
the  bloodvessels,  a  small  quantity  of  blood  is 
generally  mixed  with  the  fluid  contents  of  the 
vesicle ;  and  after  the  vesicle  has  been  emptied 
of  these  fluid  contents,  their  place  is  generally 
supplied  by  a  greater  or  less  quantity  of  coagu- 
lated blood,  probably  poured  out  by  the  same 
ruptured  vessels. 

The  membranes  of  the  vesicle  at  this  time 
have  become  thicker  than  before :  the  inner 
one  in  particular  appears  more  vascular  and 
uneven,  perhaps  in  part  from  its  being  puckered 
up  on  the  vesicle  becoming  flaccid  and  com- 
paratively empty.  The  wrinkled  appearance 
on  the  inner  surface  of  the  vesicle  increases, 
and  there  grows  gradually  out  from  it  a  new 
substance  which  comes  to  occupy  the  whole 
cavity  of  the  vesicle;  and  in  many  instances, 
as  this  new  substance  is  formed  in  greater 
quantity  than  can  be  contained  within  the  limits 
of  the  vesicle,  it  protrudes  some  way  out  at 
the  opening  of  the  vesicle,  forming  a  dark  red 
prominence  like  a  nipple,  which  rises  above 
the  neighbouring  surface  of  the  ovary.  This 
substance,  at  the  time  of  its  first  formation,  is 
of  a  pink  or  reddish  colour,  but  as  it  becomes 
gradually  less  filled  with  blood  it  acquires  a 
yellowish  hue,  which  is  more  or  less  apparent 
in  different  animals.  In  the  human  species  it 
is  of  a  bright  yellow  colour,  whence  the  name 
of  corpus  luteum  applied  to  this  new  produc- 
tion of  the  ovarian  vesicles. 

The  substance  of  the  corpus  luteum  has  a 
lobular  structure;  the  lobules  radiating  in  a 
somewhat  irregular  manner  from  the  centre  to 
the  circumference.  The  central  part  of  the 
corpus  luteum  frequently  remains  hollow  for 
some  time  after  its  production,  opening  ex- 
teriorly by  a  narrow  passage  from  the  place 
where  the  rupture  of  the  vesicle  originally  took 
place;  at  other  times  this  passage  is  closed 
more  early,  and  there  remains  nothing  but  an 
indication  of  its  place  in  a  depression  in  the 
centre  of  the  most  projecting  part  of  the  corpus 
luteum.  The  lobules  of  the  corpus  luteum, 
examined  with  the  microscope,  exhibit  merely 
a  granular  structure,  and  are  not  formed  of 
acini,  as  some  have  described  them,  so  that 
there  is  no  reason  to  consider  these  bodies  as 
of  a  glandular  nature. 

The  size  which  corpora  lutea  attain  when 
fully  developed  varies  much  in  the  same  and 
in  different  animals.  In  the  human  female 
they  become  as  large  as  a  common  hazel-nut ;  in 
the  cow  they  are  sometimes  as  large  as  a  ches- 

*  The  ovarian  capsules  of  the  bird,  which  are 
obviously  the  analogous  parts  of  the  ovarian 
vesicles  of  quadrupeds,  present  on  their  most  pro- 
minent part  a  remarkable  band,  extending  for 
nearly  one-third  of  the  periphery  :  towards  the 
margins  of  this  band  the  small  bloodvessels  all 
converge,  but  they  do  not  pass  upon  the  band 
itself,  so  that  it  is  left  free  from  bloodvessels.  It 
is  in  this  non-vascular  or  less  vascular  part  of  the 
capsule  that  the  rupture  takes  place  when  the  yolk 
escapes. 


450 


GENERATION. 


nut ;  and  in  the  sow  or  ewe  they  are  somewhat 
larger  than  full-grown  peas. 

The  corpus  luteum  may,  by  dissection,  be 
easily  separated  from  the  surrounding  parts  and 
turned  out  of  the  ovary;  and  when  this  is 
done,  the  external  membrane  of  the  original 
vesicle  remains  lining  the  cavity  left  in  the 
ovary.  From  this  it  would  appear  that  the 
corpus  luteum  is  most  intimately  connected 
with  the  inner  membrane  of  the  vesicle ;  and, 
in  fact,  Baer*  observed  that,  before  the  rupture 
of  the  vesicle  in  the  dog,  the  inner  membrane 
had  become  thickened,  rugous,  and  of  a  villous 
structure,  as  if  the  corpus  luteum  grew  from 
that  internal  membrane  itself.  This  observa- 
tion also  makes  it  probable  that  the  growth  of 
the  corpus  luteum  may  contribute  to  cause  the 
rupture  of  the  vesicle. 

The  corpus  luteum  at  first  increases  gradu- 
ally in  size,  remains  for  a  time  stationary,  and 
then  decreases  till  it  either  wholly  disappears 
or  leaves  only  a  small  mark  or  cicatrix  to  indi- 
cate its  place.  The  time  at  which  it  attains 
its  full  size  seems  to  vary  considerably.  In 
the  sheep  two  or  three  days  are  sufficient  for 
the  formation  of  the  corpus  luteum,  and  its 
cavity  becomes  obliterated  within  a  fortnight 
after  copulation.  Haller  found  corpora  lutea 
in  the  dog  on  the  sixth  day;  Cruikshank 
observed  the  corpora  lutea  to  go  on  progres- 
sively increasing  till  the  ninth  day  in  the 
rabbit ;  and  it  is  probable  that  in  the  human 
species  the  corpus  luteum  is  not  fully  developed 
till  after  the  second  month  of  pregnancy. 

After  the  corpus  luteum  has  attained  its  full 
magnitude,  its  colour  becomes  paler  and  of  a 
clearer  yellow;  its  size  then  gradually  dimi- 
nishes, its  tissue  becomes  more  compact,  its 
cavity  is  obliterated,  and  it  is  converted  into  a 
body  nearly  solid.  It  generally  retains,  during 
utero-gestation,  a  considerable  size,  and  this 
remark  applies  especially  to  the  human  species, 
in  which  it  diminishes  much  more  rapidly  in 
size  after  than  before  the  birth  of  the  child.  In 
some  animals  it  at  last  wholly  disappears ;  in 
others,  among  which  is  the  human  species,  it 
always  leaves  some  mark. 

In  what  has  now  been  said  regarding  the 
corpus  luteum,  that  body  has  been  described 
as  it  is  formed  in  the  place  of  a  vesicle  which 
has  been  burst  after  fruitful  sexual  union  ;  but 
we  may  remark  that  the  same  series  of  changes 
always  follows  the  rupture  of  an  ovarian 
vesicle  from  whatever  cause  that  may  have 
proceeded.  It  is  now  well  known  that  in 
some  animals  the  rupture  of  ovarian  vesicles 
and  subsequent  changes  take  place  without 
sexual  union  merely  from  the  state  of  heat  or 
venereal  excitement  of  any  kind,  while  in 
others  these  phenomena  are  never  observed 
but  as  accompaniments  of  conception.  The 
sow  and  mare  belong  to  the  first  of  these  classes 
of  animals.  The  rabbit,  bitch,  ewe,  and  cow 
may  be  mentioned  as  examples  of  the  second,  as 
also  is  generally  the  case  in  the  human  female ; 
but  in  woman,  as  in  some  other  females,  various 
circumstances  induce  us  to  believe  that  the 

*  See  Epistola,  &c. 


rupture  of  ovarian  vesicles  and  the  formation 
of  corpora  lutea  in  their  place  occasionally 
happen  without  sexual  union  from  all  those 
causes  which  excite  greatly  the  sexual  organs; 
and  we  are  not,  therefore,  inclined  to  admit 
the  presence  of  a  corpus  luteum,  taken  alone, 
as  a  certain  sign  of  sexual  union  having  oc- 
curred ;  though  conjoined  with  other  signs,  the 
presence  of  one  or  more  corpora  lutea  or  the 
appearance  of  ruptured  vesicles  must  be  re- 
garded as  good  presumptive  evidence. 

In  some  of  those  animals  in  which  vesicles 
frequently  burst  without  sexual  union,  there 
are  occasionally  very  many  corpora  lutea  in 
the  ovary,  so  as  to  alter  completely  its  form,  and 
disguise  its  natural  structure,  as  may  frequently 
be  seen  in  the  sow.  In  those  animals  again 
in  which  sexual  union  alone  brings  about  the 
rupture,  we  at  once  distinguish  the  ovary  of 
the  unimpregnated  animal  from  that  of  the  one 
that  has  had  connexion  with  the  male,  and  we 
very  generally  observe  an  exact  correspondence 
in  the  number  of  corpora  lutea  and  the  ova  or 
foetuses  contained  in  the  uterus;*  and  the 
same  correspondence  is  very  frequently  found 
after  conception,  even  in  those  animals  in  which 
corpora  lutea  are  formed  without  sexual  union. 

While  the  corpus  luteum,  then,  is  always  to 
be  found  in  the  ovary  of  a  pregnant  quadruped, 
the  formation  of  this  body  is  to  be  regarded  as 
the  uniform  consequence  of  the  rupture  of  the 
ovarian  vesicles,  whether  that  rupture  shall 
have  been  occasioned  merely  by  excitement  of 
the  organs,  or  by  productive  or  unproductive 
sexual  union ;  but  it  is  only  when  conception 
and  pregnancy  occur  that  the  corpus  luteum 
attains  its  full  size,  and  runs  through  the  whole 
of  that  series  of  changes  which  we  have  described 
as  peculiar  to  that  body. 

We  ought  not  to  omit  here  the  mention  of  a 
totally  different  view  which  has  been  taken  of 
the  corpora  lutea,  that,  viz.  of  Buffon  and  Val- 
lisneri,f  supported  more  recently  by  Sir  E. 
IIome,J  according  to  which  it  is  held  that  the 
corpora  lutea  exist  before  the  rupture  of  the 
vesicles,  and  are  the  matrix  in  which  the  vesicles 
and  ova  are  formed. 

Two  circumstances  principally  have  been 
brought  forward  in  favour  of  this  hypothesis  : — 
1st,  that  corpora  lutea  occur  in  the  virgin  state ; 
and  2d,  that  they  frequently  contain  vesicles. 
Now  the  existence  of  corpora  lutea,  we  have 
already  stated,  in  the  sow  (observed  by  Sir  E. 
Home;,  and  even,  we  are  inclined  to  hold,  in 
the  human  female,  is  not  necessarily  a  proof 
of  sexual  union  having  previously  occurred, 
since  the  rupture  of  the  vesicles  may  have 

*  It  may  be  mentioned  that  more  than  one  ovum 
have  sometimes  been  found  in  the  same  Graafian 
vesicle,  in  which  case  it  will  readily  be  understood 
there  might  be  only  one  corpus  luteum  in  the  ovary 
and  two  ova  in  the  uterus,  but  this  is  rare.  The 
author  has  verified  the  above  correspondence  in 
many  hundred  pregnant  ewes,  in  a  considerable 
number  of  cows,  rabbits,  some  cats,  and  other 
animals. 

t  Vallisneri,  Hist,  of  the  Generation  of  Man  and 
Animals  (Ital.). 

i  Phil.  Trans.,  vol.  cviii.  p.  256,  and  vol.  cix. 
p.  59. 


GENERATION. 


451 


followed  simple  excitement  of  the  sexual 
organs,  and  might  therefore  take  place  either 
with  or  without  the  male  ;  and  in  the  second 
place,  the  occurrence  of  cavities  and  vesicular 
membranes  within  the  corpora  lutea  is  by  no 
means  a  proof  that  these  cavities  are  new  or 
forming  ovarian  vesicles ;  on  the  contrary,  there 
is  every  reason  to  regard  them  as  unnatural  or 
the  product  of  disease.  But  though  lately 
revived  upon  the  above-mentioned  grounds,  it 
is  long  since  this  hypothesis  received  the  most 
satisfactory  refutation,  both  from  the  observa- 
tions of  De  Graaf  and  of  Haller.  Haller  in 
particular  traced  in  the  most  accurate  manner 
all  the  steps  of  the  development  of  the  corpus 
luteum,  from  the  first  rupture  of  the  vesicle 
till  its  completion :  he  employed  the  animals 
least  liable  to  lead  to  fallacy  in  such  observa- 
tions; those,  viz.  in  which  rupture  of  the 
vesicles  and  formation  of  corpora  lutea  is 
usually  produced  only  by  sexual  union  ;  and 
he  always  remarked  in  them  an  exact  corres- 
pondence in  the  number  of  fcetuses  in  the 
gravid  uterus  with  the  number  of  corpora  lutea 
in  the  ovaries,  while  at  the  same  time  he  found 
the  first  appearance  of  these  bodies  to  take 
place  at  a  fixed  period  after  sexual  union,  and 
their  size  and  structure  always  to  bear  an  exact 
relation  to  the  period  of  utero-gestation  at 
which  they  were  observed.* 

The  uses  of  the  corpora  lutea  are  entirely 
unknown.  The  fact  that  these  bodies  become 
larger  and  remain  proportionately  of  a  larger 
size  during  pregnancy  than  when  produced  in 
other  circumstances  (as  without  sexual  union, 
or  after  unproductive  copulation,  or  when  the 
product  is  blighted  at  an  early  period  of  utero- 
gestation,)  would  seem  to  indicate  some  con- 
nexion between  the  corpora  lutea  and  the 
development  of  the  foetus  in  utero.  By  those 
who  have  regarded  the  corpora  lutea  as  of  a 
glandular  nature,  they  have  been  supposed  to 
secrete  fluids  which  assist  in  the  nourishment 
of  the  foetus.  We  have  already  stated  the 
reasons  for  considering  such  hypotheses  as 
groundless.    (See  Ovary.) 

Descent  of  the  ovum.  Its  structure  and 
changes  during  its  passage. — The  attention  of 
accoucheurs  in  all  ages  and  countries  has 
naturally  been  directed  to  the  study  of  the 
structure  of  the  human  ovum  and  foetus  in  the 
more  advanced  stages  of  utero-gestation,  and 
a  great  body  of  facts  has  been  collected  from 
the  examination  of  aborted  products  or  the 
gravid  uterus  of  women  dying  during  preg- 
nancy, from  which  scientific  men  have  acquired 
an  accurate  knowledge  of  the  structure  of  the 
human  foetus  and  its  covering  in  the  ovum 
during  the  greater  part,  and  especially  in  the 
more  advanced  period  of  utero-gestation  ;  but 
very  little  is  known  of  the  nature  of  the  egg 
in  the  first  stages  or  immediately  after  concep- 

*  The  corpus  luteum  is  developed  then  and  be- 
comes perceptible  after  tbe  bursting  of  one  of  the 
vesicles  ;  but  let  us  not  here  lose  sight  of  the  fact 
before  announced  that  the  first  commencement  of 
its  formation  dates  from  a  short  while  before  the 
rupture,  as  indicated  by  a  thickening  of  the  inner 
membrane  of  the  vesicle. 


tion  has  occurred.  We  have,  in^fact,  no  direct 
observations  which  inform  us  of  what  happens 
to  the  human  ovum  immediately  after  its  escape 
from  the  ovary,  and,  indeed,  for  some  little 
time  after  its  arrival  in  the  uterus,  when  the 
parts  of  the  foetus  have  already  begun  to  be 
formed  in  it.  This  subject  has,  however,  been 
investigated  with  considerable  success  in  several 
mammiferous  animals ;  and  although  there 
remain  several  points  which  still  require  eluci- 
dation, yet,  from  the  analogy  whicli  is  known  to 
exist  in  the  structure  of  the  ovum  and  foetus 
of  the  human  species  and  those  of  quadrupeds 
and  birds,  we  are  enabled  to  bring  together  the 
detached  observations  which  chance  has  thrown 
in  our  way,  and  thus  to  give  a  connected 
account  of  the  generative  process  in  man,  im- 
perfectly as  that  process  has  as  yet  been 
observed. 

Our  design  at  present  is  to  follow  the  ovum 
only  as  far  as  into  the  uterus,  or  until  the  com- 
mencement of  the  formation  of  the  foetus  in  it. 
We  believe  we  shall  place  this  part  of  our  sub- 
ject in  the  clearest  point  of  view,  by  prefixing 
to  our  remarks  regarding  the  ovum  of  man 
and  quadrupeds  a  short  sketch  of  what  happens 
to  the  egg  of  the  common  fowl  after  its  dis- 
charge from  the  ovary. 

The  substance  of  the  yolk  enclosed  in  its 
membrane,  together  with  the  germinal  portion 
in  which  after  incubation  the  rudiments  of  the 
new  animal  begin  to  be  formed,  constitutes  the 
essential  parts  of  the  bird's  egg  as  it  exists  in 
the  ovary.  The  ovarian  egg,  when  it  has  left 
the  place  of  its  formation  and  passed  into  the 
oviduct,  receives  the  addition  of  various  other 
parts,  viz.  the  albumen,  chalazae,  shell  and 
its  lining  membrane,  as  it  gradually  descends 
through  different  portions  of  the  oviduct,  each 
of  which  is  destined  to  secrete  one  of  these 
newly  added  parts.  These  parts  may,  however, 
be  considered  as  accessory  to  the  more  essential 
constituents  of  the  egg,  which  we  are  inclined 
to  regard  as  the  germinal  spot  or  cicatricula, 
the  granular  and  oleaginous  fluid  of  the  yolk, 
and  the  dense  transparent  membrane  with 
which  they  are  enveloped.  To  the  unim- 
pregnated  egg  of  the  ovary  we  shall  give  the 
name  of  ovulum,  and  henceforward  in  this 
paper  apply  the  name  of  ovum  to  the  perfected 
egg,  that  is,  the  ovulum  to  which  the  acces- 
sory coverings  have  been  added,  and  which 
has  received  the  influence  of  the  male.  The 
ovarium  of  the  common  fowl  in  the  breeding 
season,  or  when  it  is  laying  eggs,  has  the  form 
of  a  bunch  of  clustering  ovula,  which  are 
contained  in  capsules,  the  more  advanced  of 
which  hang  down  from  the  rest  of  the  ovary 
by  the  elongated  pedicles  of  the  containing 
capsules ;  while  the  smaller  ovula  of  various 
sizes,  composing  the  body  of  the  ovary,  cluster 
more  closely  together.  The  fully  developed 
ovula  only  have  the  deep  yellow  colour  pecu- 
liar to  the  yolk ;  as  the  smaller  ones  are  less 
advanced  their  colour  is  paler,  and  the  smallest 
are  nearly  colourless  and  transparent  from 
the  absence  in  them  of  the  oleaginous  and 
granular  matter  peculiar  to  the  riper  yolks. 

The  little  white  spot  or  granular  layer  whicli 


452 


GENERATION. 


constitutes  the  cicatricula  or  germinal  disc  is 
easily  seen  in  the  larger  ovula,  occupying 
almost  always  the  same  position  on  the  surface 
of  the  yolk,  somewhere  near  the  pedicle  of 
the  ovarian  capsule.  When  the  cicatricula  is 
examined  carefully  in  the  ovulum,  a  small 
dark  round  spot  is  perceived  in  its  centre,  the 
relations  of  which  to  the  first  production  of  the 
foetus  are  very  important.  This  little  dark 
spot  was  discovered  by  Purkinje  to  contain  im- 
planted in  the  centre  of  the  cicatricula  a  minute 
transparent  vesicle  filled  with  fluid.  He  farther 
shewed  that  during  the  passage  of  the  ovulum 
from  the  capsule  of  the  ovary  into  the  infun- 
dibulum  of  the  oviduct,  this  little  vesicle  dis- 
appears, being  probably  burst,  and  leaves  in 
its  place  a  thin  and  tender  transparent  mem- 
brane. The  vesicle  of  Purkinje,  as  it  is  called 
from  its  discoverer,  occupies  then  the  centre  of 
the  germinal  spot,  and  it  is  in  the  transparent 
membrane  left  in  its  place  when  the  vesicle  is 
dispelled  that  the  first  rudiments  of  -the  foetus 
afterwards  make  their  appearance.  Hence  the 
vesicle  has  also  received  the  name  of  germinal 
vesicle,  a  most  appropriate  term,  since  it  may 
be  regarded  as  the  more  immediate  seat  of  the 
germ  or  germinating  faculty  of  the  egg. 

The  Purkinjean  or  germinal  vesicle  exists  in 
the  smallest  as  well  as  in  the  more  advanced 
ovula  of  the  fowl's  ovary,  and  it  is  proportion- 
ally much  larger  in  small  than  in  large  ovula. 
In  the  very  small  ovula  it  is  not,  as  in  the  riper 
ones,  situated  on  the  surface  of  the  yolk,  but 
towards  the  centre  of  that  body;  and  as  the  ovu- 
lum advances  to  perfection,  the  germinal  vesicle 
gradually  approaches  more  near  the  surface, 
and  becomes  more  prominent  on  the  surface  of 
the  cicatricula.  In  ovula  less  than  two  lines 
in  diameter  the  vesicle  is  usually  unconnected 
with  the  germinal  layer  or  cicatricula,  but  in 
those  of  four  lines  in  diameter  it  is  already 
placed  in  the  middle  of  the  germinal  spot. 

In  all  oviparous  animals  a  vesicle,  simi- 
lar to  that  now  described  in  the  common  fowl, 
occupies  the  central  part  of  the  germinal  layer 
so  long  as  the  ovulum  remains  in  the  ovary, 
and  undergoes  the  same  rupture  and  other 
changes  at  the  time  of  the  discharge  of  the 
ovulum  from  the  ovary.* 

In  turning  now  to  mammiferous  or  vivipa- 
rous animals,  it  may  be  remarked  in  the  first 
place,  that  although  the  extremely  minute  size 
of  the  body  discovered  by  Baer  to  be  constantly 
present  in  the  ovarian  vesicle  prevents  us  from 
observing  it  with  ease,  and  establishing  with 
certainty  its  analogy  to  the  yolk  and  its  accom- 
panying parts  in  the  egg  of  the  fowl  before  deve- 
lopment begins ;  yet  after  the  commencement 

*  Purkinje's  description  of  this  vesicle  was  first 
given  in  his  excellent  "  Symbolae  ad  ovi  ovium 
historiam  ante  incubationem,  Vratisl.  1825,"  and 
second  edition  at  Leipzig,  in  1830.  Baer  contri- 
buted in  his  "  Epistola"  many  important  facts 
concerning  its  existence  and  changes  in  other  ovi- 
parous animals.  Coste,  Valentin,  and  Wagner 
have  since  added  several  observations.  We  may 
state  here  that  the  bursting  of  the  vesicle  does  not 
occur  in  all  oviparous  animals  exactly  at  the  time 
of  the  escape  of  the  ovulum  from  the  ovary,  but 
nearly  about  the  same  time. 


of  foetal  formation,  the  early  changes  which  this 
body  undergoes  prove  its  correspondence  with 
the  ovum  of  birds  in  a  most  satisfactory  manner. 
We  have  already,  however,  stated  the  reasons 
for  regarding  the  vesicle  of  Baer  as  the  ovulum 
of  mammalia,  and  need  not  now  recapitulate 
them.  We  shall  only  remark  that  although 
the  vesicle  of  Baer  and  ovulum  of  birds  differ 
widely  in  size,  that  vesicle  appears  to  contain 
the  same  essential  parts  of  the  egg  belonging 
to  birds  and  other  oviparous  animals,  viz.  a 
fluid  granular  mass  or  yolk  enclosed  by  an  in- 
vesting membrane,  and  furnished  also  with  a 
more  compact  granular  layer  situated  on  the 
surface  of  the  yolk,  but  also  enveloped  by  its 
membrane,  in  which  the  rudiments  of  the 
fcetus  first  appear,  and  which  is,  therefore,  the 
germinal  layer  of  the  mammiferous  ovum. 

The  membranes  of  the  ovarian  vesicle  in 
mammalia  and  the  capsules  of  the  ovary  in 
the  fowl  are  corresponding  parts,  and  the  prin- 
cipal difference  between  the  ovarian'  cavities 
containing  ovula  in  oviparous  animals,  and 
those  of  viviparous  animals,  consists  in  this, 
that  in  the  latter  the  ovulum  (the  vesicle  of 
Baer)  is  placed  in  the  granular  proligerous  disc, 
and  has  all  the  fluid  of  the  vesicle  interposed 
between  it  and  the  coats  of  this  cavity. 

At  the  time  when  Baer  first  discovered  the 
ovulum  of  mammalia,  there  was  still  wanting, 
in  order  to  complete  the  proof  of  its  analogy  witli 
the  ovulum  of  birds,  the  observation  of  the  ger- 
minal vesicle  (vesicle  of  Purkinje)  within  it. 
This  additional  proof  has  been  supplied  within 
the  last  few  years  by  the  researches  of  T.  W. 
Jones,  Coste,  Purkinje,  Valentin,  and  Wag- 
ner, which  we  have  ourselves  confirmed. 

The  germinal  vesicle  of  the  very  small  ovu- 
lum of  quadrupeds  is  of  course  a  most  minute 
object,  and  in  fact  it  can  only  be  seen  with  a 
good  microscope ;  but  in  favourable  circum- 
stances it  is  nevertheless  quite  distinct,  and 
the  investigations  above  referred  to,  conjoined 
with  analogical  evidence,  make  it  highly  pro- 
bable that  the  little  vesicle  found  within  the 
ovulum  of  viviparous  animals  occupies  the 
place  in  which  the  foetus  first  makes  its  ap- 
pearance, and  that  at  the  time  of  the  passage 
of  the  ovulum  from  the  ovary  to  the  Fallopian 
tube  this  little  vesicle  is  burst,  and  undergoes 
analogous  changes  to  those  which  have  been 
noticed  in  the  fowl.* 

In  birds  the  shell  with  its  lining  membrane 
forms  the  external  covering  of  the  egg ;  and  in 
all  oviparous  animals  a  similar  external  enve- 
lope (besides  the  membrane  enclosing  the  yolk) 
is  to  be  found,  though  varying  greatly  in  thick- 
ness, consistence,  and  structure  in  different 
animals.    The  ovum  of  mammalia  at  the  time 

*  In  his  "  Epistola,"  published  in  1827,  Baer 
compared  the  vesicle  he  had  discovered  within  the 
Graafian  vesicles  of  the  ovary  to  the  vesicle  which 
Purkinje  had  in  1825  discovered  in  the  cicatricula 
of  the  fowl's  yolk:  erroneously  as  we  think;  for 
the  facts  mentioned  above  are  sufficient  to  disprove 
any  such  analogy.  For  the  sake  of  clearness  we 
here  subjoin  a  tabular  view  of  the  parts  which 
correspond  with  one  another  in  the  bird  and  quad- 
ruped. 


GENERATION. 


453 


when  it  arrives  in  the  uterus  has  also  a  similar 
external  envelope,  which  has  received  in  man 
and  most  animals  the  general  appellation  of 
chorion.  Baer  is  of  opinion  that  the  chorion 
exists  ready  formed  in  the  ovulum  of  the 
ovary  ;  but  his  observations  appear  to  us  as 
yet  insufficient  to  prove  this  point,  and  we  feel 
inclined  rather  to  adopt  the  view  of  Valentin, 
who  holds  that  it  is  probable  that  the  chorion 
is  added  to  the  ovulum  after  it  has  left  the 
Graafian  vesicle,  that  is,  during  its  passage 
from  the  ovary  to  the  uterus,  somewhat  in  the 
same  manner  as  the  albumen  or  shell  is  added 
to  the  egg  of  the  common  fowl  in  its  passage 
through  the  oviduct.  The  analogy  of  all  ovi- 
parous animals  is  at  least  strongly  in  favour  of 
such  a  view  of  the  mode  of  the  production  of 
the  chorion  or  external  envelope  ;  while  on  the 
other  hand  we  ought  not  to  lose  sight  of  the 
fact  that  though  the  external  envelope  or  cho- 
rion occupies  the  same  position  as  the  external 
covering  of  the  eggs  of  oviparous  animals,  its 
structure  and  functions  are  very  different,  for 
almost  in  every  quadruped  the  chorion  serves 
important  purposes  in  establishing  that  more 
intimate  union  peculiar  to  viviparous  animals, 
which  is  formed  between  the  ovum  and  uterus 
in  the  placenta  or  analogous  structure. 

It  is  only  in  the  dog  and  rabbit  that  the  ova 
have  hitherto  been  traced  by  actual  observation 
in  the  whole  course  of  their  progress  through  the 
Fallopian  tubes  from  the  ovary  to  the  uterus. 
These  observations  we  owe  chiefly  to  the  care- 
ful researches  of  Cruikshank,  Prevost  and 
Dumas,  Baer,  and  Coste.  In  regard  to  other 
animals  we  have  only  a  few  detached  observa- 
tions in  some  of  them,  and  in  the  human 
species  the  ova  have  never  been  observed  in  the 
Fallopian  tubes,  nor  indeed  for  some  time 
after  they  must  have  entered  the  uterus.  We 
do  not  therefore  know,  with  any  degree  of  cer- 
tainty, at  what  distance  of  time  after  sexual 
union  the  ovum  passes  into  the  uterus  of  the 
human  female.  Great  difficulties  attend  the 
elucidation  of  this  point.  In  the  first  place, 
we  are  opposed  by  the  impossibility,  in  the 
greater  number  of  cases  in  which  we  may  hap- 
pen to  obtain  a  pregnant  uterus  for  investiga- 
tion, of  knowing  accurately  the  age  of  the 
product  or  the  time  at  which  impregnation  has 
occurred;  and  in  the  second  place,  we  are 
here  deprived   of  the  assistance  derived  in 


In  the  Quadruped. 

1.  The  ovary  contains 

2.  Graafian  vesicles 
which  are  filled  with 
fluid,  granules,  and 
the  proligerous  disc, 
in  the  centre  of  which 
is  placed 

3.  The  ovulum  or  vesi- 
cle of  Baer,  consisting 
of 

4.  A  yolk,  on  the  sur- 
face of  which  is 

5.  A  germinal  membrane, 
in  the  middle  of  which 
is  placed 

6.  The  germinal  vesicle 
or  vesicle  of  Pnrkinjc. 


In  the  Bird. 

1.  The  ovary  contains 

2.  Capsules  entirely  filled 
with  ovula,  there  being 
no  intervening  fluid  or 
proligerous  disc. 


3.  The  ovula  or  yolks, 
consisting  of 

4.  A  yolk. 

5.  A  germinal  membrane 
or  cicatricula  with  the 

6.  Vesicle  of  Purkinje  in 
its  centre. 


many  other  parts  of  our  subject  from  analogical 
evidence  by  the  wide  discrepancies  we  find 
among  animals  in  respect  to  the  period  of  the 
arrival  of  the  ova  in  the  uterus  ;  for  there  does 
not  appear  to  be  any  exact  correspondence  yet 
shewn  between  the  time  at  which  this  happens 
and  the  length  of  duration  of  utero-gestation. 
It  may  be  well,  however,  to  endeavour  to 
form  an  approximative  opinion.  In  the  rabbit, 
although  ova  are  known  frequently  to  be  dis- 
charged from  the  Graafian  vesicles  on  the  se- 
cond day  after  sexual  union,  they  are  in  general 
not  detected  in  the  uterus  before  the  third  or 
fourth  day,  and  frequently  not  before  the  fifth 
or  sixth,  at  which  time  they  appear  as  vesicles 
a  little  more  than  a  line  in  diameter,  lying  un- 
attached in  the  upper  part  of  the  coniua  of  the 
uterus.* 

In  the  dog  ova  have  been  observed  in  the 
Fallopian  tubes  on  the  eighth  day,  but  they 
have  not  been  found  in  the  uterus  before  the 
twelfth  day.  In  the  cat  we  have  found  ova  of 
the  size  of  peas  beginning  to  be  attached  to 
the  uterus  at  the  twelfth  day,  and  in  both  the 
cat  and  dog  we  think  it  probable  from  the  size 
of  the  ova  that  they  had  already  been  in  the 
uterus  for  at  least  one  day,  so  that  the  tenth 
or  eleventh  day  may  be  regarded  as  the  time 
when  ova  generally  appear  in  the  uterus  of 
these  animals. 

Hallerand  Kuhlemannf  never  found  an  ovum 
in  the  uterus  of  the  sheep  till  the  seventeenth 
day  after  copulation,  and  our  own  observations 
on  both  the  sheep  and  sow  agree  precisely 
with  theirs.  Ilausmann  never  found  the  ova 
in  the  uterus  of  the  sow  before  the  period  of 
four  weeks  after  conception,  and  those  of  the 
bitch  before  three  weeks  ;  but  here  we  must 
caution  the  reader  against  the  error  of  sup- 
posing that  in  the  sheep  and  some  other 
animals,  because  the  ova  have  not  been  ob- 
served in  the  uterus,  they  do  not  actually 
exist  there  previous  to  a  certain  date  ;  for  the 
large  size  of  the  ovum  and  its  membranes,  as 
well  as  the  state  of  the  fetus,  which  though 
small  is  already  somewhat  developed,  entitle 
us  to  conclude  that  the  ovum  of  the  sheep 
must  have  been  some  time  in  the  uterus.  The 
recent  interesting  observations  by  M.  Coste 
have  thrown  great  light  upon  this  subject,  he 
having  detected  the  ova  of  the  sheep  so  early 
as  five  days  after  conception.  In  the  cow  also, 
in  which  the  period  of  gestation  is  nearly  twice 
the  length  of  that  in  the  sheep,  the  ovum 
seems  to  arrive  almost  as  early  in  the  uterus, 
if  we  may  judge  from  the  state  of  advancement 
of  the  fetus  at  an  early  period. J 

*  M.  Coste  has  shewn  that  there  is  considerable 
variety  in  respect  to  the  time  at.  which  the  ova 
descend  in  the  rabbit,  and  thus  very  reasonably 
accounts  for  the  difference  one  generally  finds  in 
the  state  of  advancement  of  the  ova  in  the  prc°-- 
nant  uterus. 

f  Vide  Kuhlemann's  Ohserv.  quaid.  circa  nego- 
tium  generationis  in  ovibus  fact.  Gott.  1753. 

|  Immediately  after  the  arrival  of  the  mammi- 
ferous  ovum  in  the  uterus  it  increases  in  bulk  with 
amazing  rapidity,  and  its  membranes  being  thus 
suddenly  dilated  become  in  consequence  very  weak 
and  thin ;  so  tender  indeed  are  they,  that  if  they 


454 


GENERATION. 


With  regard  now  to  the  time  at  which  the 
ovum  first  enters  the  uterus  in  the  human  fe- 
male, let  us  examine  the  facts  which  are 
before  us.  The  greater  number  of  observations 
of  this  kind  are  made  on  aborted  products  ; 
many  of  these  are  malformed  or  diseased,  in 
consequence  of  which  very  probably  they  have 
been  thrown  off  by  abortion  ;  others  are  injured 
by  the  violence  of  the  action  which  causes  the 
uterus  to  be  emptied  of  its  contents.  Our 
know  ledge  of  the  time  of  conception  is  generally 
founded  upon  the  cessation  of  the  menstrual 
flow  on  the  first  occasion  when  it  ought  to 
have  recurred  after  conception  has  taken  place, 
and  conception  may  in  the  greater  number  of 
instances  have  taken  place  at  any  period  of  the 
interval.  In  a  very  few  cases  only  have  we 
any  means  of  determining  the  time  of  concep- 
tion, and  in  still  fewer  instances  has  there  been 
an  opportunity  of  examining  the  uterus  in  situ 
at  an  early  period  after  conception  when  the 
period  of  sexual  intercourse  was  known.  In 
by  far  the  greater  number  of  instances,  there- 
f  e,  there  may  be  an  error  in  the  calculation  of 
ten  days  or  a  fortnight. 

It  is  by  no  means  rare  to  see  specimens  of 
the  human  ovum  or  foetus  in  anatomical  col- 
lections marked  as  being  a  fortnight  or  three  or 
four  weeks  old  ;  but  it  is  now  generally  ac- 
knowledged that  the  greater  number  of  these 
are  incorrectly  marked.  We  have  seen,  however, 
more  than  one  such  ovum,  which,  both  from 
the  history  of  the  cases  and  from  the  structure 
and  size  of  the  parts  of  the  ovum  and  foetus, 
we  should  be  inclined  to  consider  as  dating 
between  three  and  four  weeks  after  concep- 
tion.* 

once  burst  it  is  impossible  to  recognize  any  parts 
of  the  ovum,  frequently  in  instances  where  we 
are  certain  it  has  existed.  Baer  in  a  second 
epistle  (published  in  Breschet's  Repertoire,  vol. 
viii.  p.  175)  mentions  these  difficulties  of  mani- 
pulation in  extracting  the  ova  from  the  gravid 
uterus  of  the  dog  during  the  early  periods,  and 
advises  that,  on  account  of  the  violent  contrac- 
tions which  are  apt  to  ensue  in  the  uterus  from 
its  exposure  to  the  air,  the  animals  should  not 
be  opened,  but  left  perfectly  quiet  for  eight  or 
twelve  hours  or  more  after  death.  We  have  fre- 
quently pursued  this  plan  advantageously  in  the 
rabbit  and  cat ;  and  have  even  found  it  neces- 
sary to  harden  the  ovum  and  uterus  in  alcohol 
beiore  being  able  to  extract  the  former.  The  same 
circumstances  may  account  for  our  never  finding  the 
ovum  of  the  sheep  before  the  seventeenth  day,  for 
those  we  examined  were  all  killed  at  the  market, 
and  consequently  opened  immediately  after  death 
while  the  contractility  still  remained  in  the  uterus. 
At  earlier  periods  we  have  in  fact  frequently  found 
shreds  of  membrane,  and  some  of  the  earliest  ova 
which  we  found  were  partly  destroyed;  but  in  a 
very  short  time  afterwards  the  membranes  of  the 
egg  and  parts  of  the  foetus  acquire  sufficient  con- 
sistence to  resist  the  pressure. 

*  So  common  in  museums  are  the  specimens  of 
blighted  ova  which  are  considered  as  examples  of 
very  early  date,  that  the  author  confines  himself 
here  to  the  mention  of  those  which  he  has  himself 
seen,  making  this  general  remark,  that  in  all  those 
specimens  below  the  alleged  age  of  six  or  seven 
weeks,  in  which  the  foetus  and  membranes,  parti- 
cularly the  amnion,  are  disproportionate  in  size, 
that  is,  the  first  very  small  and  the  latter  large, 


There  are  some  who  describe  the  human 
fcetus  at  less  than  a  fortnight  old,  and  even  as 
early  as  the  eighth  day,  as  in  the  well-known 
and  often-quoted  example  described  by  Sir  E. 
Home.  But  there  is  some  reason  to  think  that 
Sir  E.  Home  was  mistaken  in  the  case  alluded 
to.  Either,  supposing  that  conception  had 
occurred  eight  days  before  death,  the  body 
in  question  was  not  the  fcetus,  or  if  it  Was  the 
fcetus,  it  must  have  been  considerably  older 
than  he  supposed. 

The  earliest  example  of  the  human  ovum 
with  which  we  are  acquainted  is  that  mentioned 
by  M.  Velpeau  in  his  work  sur  t '  Embryologie 
Humaine ;  which,  if  he  was  not  deceived  by 
the  person  who  gave  it  to  him,  he  had  the  best 
reason  to  believe  was  discharged  on  the  four- 
teenth day  after  sexual  intercourse. 

This  ovum,  the  description  and  drawings  of 
which  are  very  meagre,  is  described  as  about 
the  size  of  a  pea ;  the  fcetus  was  already  some- 
what formed,  though  very  small;  and  all  points 
of  structure  in  the  fcetus  and  ovum  appear  to 
us  (so  far  as  we  can  judge  from  the  description) 
to  correspond  with  one  another,  and  to  shew 
that  the  product  was  quite  natural.  This  ovum 
from  its  size  and  from  the  state  of  advancement 
of  the  foetus  must  have  been  in  the  uterus  at 
least  two  or  three  days. 

We  possess  also  the  recent  record  of  two 
valuable  observations  made  on  the  structure  of 
the  gravid  uterus  of  females  dying  suddenly 
eight  days  after  sexual  intercourse  ;  the  one  by 
Weber,  the  other  by  Professor  Baer.  No  ovum 
was  detected  in  either  of  these  instances  either 
in  the  uterus  or  tubes.  We  feel  inclined  to 
place  much  reliance  on  these  two  observations 
as  being  made  by  persons  well  acquainted  with 
the  various  circumstances  necessary  to  be  at- 
tended to  in  such  a  delicate  investigation,  and 
with  all  the  advantages  of  recent  knowledge, 
and  though  they  afford  negative  evidence  only, 
yet  we  are  disposed  to  found  upon  them  as 
proofs  that  at  the  eighth  day  the  ovum  has  not 
descended  into  the  uterus. 

On  comparing  the  degree  of  advancement 
of  the  fcetus  in  the  ovum  described  by  Velpeau 
and  in  others  with  that  of  the  fcetus  in  the  dog, 
cat,  and  sheep,  at  known  periods,  we  would 
hazard  the  opinion  that  the  human  ovum  arrives 
in  the  uterus  on  the  eleventh  or  twelfth  day  after 
conception.  Valentin  thinks  the  twelfth  or  four- 
teenth day,  but  we  are  inclined  to  believe  that 
it  cannot  be  much  later  than  in  the  dog. 

Change  of  the  uterus  after  conception. — 
Before  the  arrival  of  the  ovum  in  the  uterus, 
a  change  has  already  taken  place  in  the  interior 
of  that  organ  preparatory  to  the  reception  of 
the  fcetus.  An  exudation  of  a  substance  having 
many  of  the  characters  of  organizable  lymph 

then  the  product  is  unnatural,  and  we  ought  to 
judge  of  its  age  more  by  the  extent  of  the  mem- 
branes than  by  the  size  of  the  foetus.  We  feel 
inclined  to  believe  that  some  of  the  views  adopted 
by  Dr.  Pockels  of  Brunswick,  in  his  interesting 
paper  on  the  early  structure  of  the  human  ovum 
and  fcetus  (to  the  consideration  of  which  we  shall 
return  in  the  article  OVUM),  are  founded  upon  the 
examination  of  unnatural  specimens. 


GENERATION. 


455 


furnishes  a  soft  flaky  lining  to  the  cavity  of  the 
uterus,  and  serves  to  form  a  covering  of  the 
ovum  when  it  afterwards  descends  into  the 
uterus.  This  newly  formed  substance  is  re- 
flected over  the  ovum  so  as  to  give  it  a  double 
covering,  the  two  layers  of  which  constitute  the 
two  folds  of  the  decidual  membrane.  The 
decidua  is  filled  with  bloodvessels  formed  by 
a  process  of  organization  similar  to  that  which 
occurs  in  inflammatory  adhesion  by  coagu- 
lable  lymph.  These  bloodvessels  are  conti- 
nuous with  those  of  the  uterus,  and  as  the 
ovum  advances  in  the  progress  of  develop- 
ment, they  are  much  dilated  in  some  parts 
so  as  to  form  sinuses,  which  are  ultimately 
intermingled,  though  by  no  means  continuous 
with  the  bloodvessels  which  pass  out  of  the 
umbilicus  of  the  foetus.  The  placenta  or  or- 
ganic connection  between  the  female  parent 
and  child,  by  means  of  which  the  respiration 
and  partly  also  the  nutrition  of  the  latter  is  car- 
ried on,  is  in  great  part  formed  in  the  decidua 
with  which  the  flocculent  chorion  is  closely  in- 
corporated; but  the  description  of  these  parts 
belongs  to  another  place. 

In  a  former  part  of  this  essay  it  was  remarked 
that  rupture  of  the  Graafian  vesicles  and  dis- 
charge of  the  ovula  from  them,  as  well  as  the 
formation  of  corpora  lutea,  may  take  place  in 
some  animals  without  the  concurrence  of  the 
male :  there  is  reason  to  believe  that  in  some 
cases  the  decidua  may  in  part  be  formed  with- 
out conception  having  occurred,  as  in  the  cases 
of  moles,  &c.  When  these  changes  have  oc- 
curred without  conception  in  Mammalia,  it  is 
quite  possible  that  the  ova  may  have  been  car- 
ried down  the  Fallopian  tubes  ;  but  as  they  are 
unfecundated,  they  undergo  no  enlargement, 
and  consequently  we  do  not  know  what  be- 
comes of  them. 

In  many  oviparous  animals  the  same  is  the 
case,  that  is,  ova  are  frequently  discharged  from 
the  ovaries  without  the  concurrence  of  the  male, 
as  happens  in  the  common  fowl  and  other 
birds,  in  some  reptiles  and  fishes.  But  even 
in  those  animals  in  which  barren  ova  are  thus 
excreted  by  the  female,  union  with  the  male 
renders  the  exclusion  of  the  egg  more  easy  and 
regular,  and  it  is  consequently  not  uncommon 
for  female  oviparous  animals  which  are  removed 
from  the  males  to  die  at  the  season  of  breeding, 
when  the  ova  are  formed  in  their  ovaries  or  de- 
scend from  that  organ  into  the  oviduct.  This 
is  beautifully  described  by  Harvey  as  befalling 
his  lady's  parrot,  which  he  had  always  taken 
for  a  male  bird,  but  which,  after  being  much 
fondled,  died  of  "  a  corrupted  egg  impacted 
in  the  oviduct ;  "  and  also  in  a  cassowary  kept 
in  the  royal  gardens,  which,  after  being  some 
time  there,  was  excited  by  being  placed  in  the 
vicinity  of  a  male  and  female  ostrich,  and 
having  laid  one  egg,  died  of  a  second  being  re- 
tained in  the  oviduct. 

In  the  common  fowl  indeed,  when  highly 
fed,  so  great  is  the  productive  energy  both  of 
the  ovary  and  oviduct  that  they  will  continue 
to  lay  eggs  during  a  whole  season  without  the 
assistance  of  the  male  ;  but  this  is  well  known 
to  be  often  very  pernicious  to  the  bird,  as  many 


of  those  kept  without  the  cock  die ;  and  it 
not  unfrequently  happens  that  eggs,  or  bodies 
like  eggs,  are  laid  by  them  containing  no  yolk, 
but  consisting  only  of  the  albumen,  membrane, 
and  shell,  which  are  the  product  of  secretion 
from  the  oviduct,  and  that  in  others  large 
masses  of  imperfectly  formed  eggs  accumulated 
together  are  lodged  in  the  genital  passages. 

These  facts  exhibit  in  a  strong  point  of  view 
the  powerful  productive  energies  of  the  female 
generative  organs  independently  of  the  concur- 
rence of  the  male;  for  it  is  sufficiently  obvious 
from  them  that  the  greater  part  of  the  substance 
of  the  egg  is  due  to  the  female,  and  that  ova,  to 
all  appearance  perfect,*  though  unfit  for  repro- 
duction, may  be  brought  forth  by  the  female 
wholly  independent  of  the  male.  Some  authors 
also  adduce  as  examples  of  this  independent 
productive  energy  of  the  female,  the  occurrence 
of  bones,  hair,  teeth,  &c,  in  close  cysts  of  the 
ovaries  of  women  and  female  quadrupeds,  but 
this  leads  us  too  far  into  the  regions  of  vague 
supposition. 

Irregularities  in  the  descent  of  the  ovum. — 
This  appears  to  be  the  proper  place  at  which 
to  make  mention  of  a  few  irregularities  that 
have  been  observed  in  the  descent  of  the  ovum, 
which  are  attended  with  important  modifica- 
tions of  the  generative  process. 

In  the  bird  it  not  unfrequently  happens 
that  the  yolk  or  ovulum  which  has  been 
discharged  from  its  burst  capsule  in  the  ovary, 
instead  of  descending  through  the  oviduct,  and 
having  added  to  it  the  external  accessory  parts, 
escapes  from  the  infundibulum  or  oviduct  into 
the  cavity  of  the  peritoneum.  This  irregu- 
larity occurs  most  frequently  among  those 
fowls  which  are  laying  eggs  without  the 
male,  and  in  which  it  may  be  supposed  the 
usual  and  regular  performance  of  the  appro- 
priate motions  is  not  ensured  by  venereal  ex- 
citement. These  yolks  sometimes  remain  for 
some  time  in  the  cavity  of  the  abdomen,  and  are 
afterwards  gradually  removed  by  absorption  : 
in  other  instances  they  cause  death.  Upon 
every  occasion  when  the  ovulum  is  discharged 
from  an  ovarian  capsule,  the  oviduct  is  excited 
to  the  secretion  of  albumen,  membrane,  and 
shell,  and  hence  the  ova  subventanea,  which 
consist  only  of  these  accessory  parts  without  the 
yolk. 

In  other  instances,  either  from  a  mechanical 
obstruction  to  the  passage  of  the  egg,  or  from  a 
deficiency  in  the  muscular  power  of  the  oviduct, 
the  product  becomes  impacted  in  the  passage, 
and  there  are  formed  large  masses  of  accumu- 
lated ova  subventanea,  with  or  without  yolks  in 
some  part  of  the  oviduct  or  m  its  vicinity. 

In  some  instances,  extremely  rarely  met  with, 
it  is  stated  by  Geoffroy  St.  Hilaire  (Annal. 
du  Museum  d'Hist.  Naturelle)  that  ova  de- 
tained in  the  oviduct  have  become  slightly  de- 
veloped, and  the  author  owes  to  the  kind- 
ness of  his  friend,  Mr.  Daniel  Ellis,  the  his- 
tory of  several  examples  of  the  same  ano- 

*  We  shall  have  occasion  to  consider  elsewhere 
more  minutely  the  difference  between  the  li  cun- 
dated  and  the  unfecundated  ovum. 


456 


GENERATION. 


maly ;  but  it  may  be  stated  as  a  general  rule 
that  this  does  not  occur  in  oviparous  animals, 
and  more  especially  in  birds,  in  which  a  con- 
tinued supply  of  fresh  air  around  the  shell  is 
necessary  to  promote  incubation,  and  we  do 
not  know  of  any  examples  of  truly  oviparous 
animals  in  which  the  fcetus  has  been  formed  in 
an  egg  accidentally  retained  within  the  body  of 
the  parent.  In  none  of  those  which  we  have 
observed  was  there  any  appearance  of  foetal 
formation. 

It  is  possible  that  some  irregularities  in  the 
position  of  the  ovum  of  mammalia  during  ges- 
tation may  receive  an  explanation  from  mecha- 
nical disturbances  similar  to  those  we  have  now 
mentioned  in  birds  ;  for  supposing  that  in  a 
viviparous  animal  the  ovum  does  not  gain  the 
uterus  or  usual  place  of  its  abode  during  gesta- 
tion, development  of  the  fcetus  still  takes  place. 
In  those  instances  in  which  a  foetus  is  formed 
in  the  region  of  the  ovary,  or  in  what  are  termed 
ovarian  conceptions,  for  example,  it  is  not  pro- 
bable that  the  ovum  is  ever  developed  in  the 
ovary  itself  without  the  bursting  of  the  Graafian 
vesicle  :  it  may  be  fixed  close  to  the  ovary,  but 
it  is  always  independent  of  that  body.  After 
the  Graafian  vesicle  has  burst,  the  ovum  may 
be  supposed  either  not  to  have  been  received 
in  the  Fallopian  tube,  or,  after  having  entered 
that  passage,  to  have  been  expelled  from  it  by 
an  inverted  action  of  its  muscular  fibres  or  other 
causes.  Fecundated  by  the  contact  of  some  of 
the  seminal  fluid  which  has  reached  so  far 
into  the  Fallopian  tube,  the  ovum  remains  in 
the  neighbourhood  of  the  ovary,  has  a  cyst 
formed  round  it,  and  becomes  organically 
united  to  the  ovary  or  parts  in  its  vicinity  by 
structures  similar  to  those  which  unite  the  ovum 
to  the  inner  surface  of  the  gravid  uterus ;  for 
the  bloodvessels  of  the  mother  which  run  into 
the  cyst  enlarge  and  form  a  placenta  by  their 
union  and  intermixture  with  those  of  the  foetus, 
and  thus  for  a  considerable  time  (amounting 
sometimes  to  four  or  five  months)  this  ovarian 
or  extra-uterine  gestation  is  carried  on. 

In  other  instances  of  misplaced  gestation,  the 
ovum  seems  to  have  been  arrested  in  its  course 
when  more  or  less  advanced  in  the  Fallopian 
tube  ;  but  here  also  the  parts  are  susceptible  of 
all  those  remarkable  changes  and  growth  which 
favour  the  development  of  the  fcetus  in  the 
ovum.  We  mention  these  instances  of  extra- 
uterine gestation  with  the  view  of  directing  the 
reader's  attention  to  an  inference  which  may  be 
drawn  from  them,  viz.  that  all  those  changes 
of  growth  upon  which  the  development  of  the 
ovum  in  viviparous  animals  depends  may  be 
regarded  rather  as  belonging  to  the  ovum  itself 
than  as  resident  in  the  uterus  alone.  It  is 
worthy  of  remark,  however,  that  in  ovarian  and 
tubular  conceptions  the  decidua  is  formed 
within  the  uterus,  nearly  in  the  same  manner 
as  if  the  ovum  had  descended  in  the  natural 
way  into  its  cavity ;  from  which  we  may  infer 
that  the  production  of  the  decidua  is  to  be  re- 
garded as  one  of  a  series  of  changes  induced  by 
conception  in  the  internal  genital  organs,  and 
occurring  independently  of  one  another,  rather 
than  as  the  effect  of  any  stimulation  from 


the  ovum,  as  some  have  supposed.  Such  a 
decidua  in  fact  may  be  compared  to  the  sub- 
ventaneous  ovum  of  the  bird. 

Very  little  is  as  yet  known  as  to  the  physical 
circumstances  (independent  of  malformation  of 
the  organs)  which  may  give  rise  to  misplaced 
gestation ;  and  this  is  not  a  subject  which  we 
can  hope  to  have  illustrated  by  observation  or 
experiment.  One  or  two  cases  are  on  record, 
however,  from  which  it  might  appear  possible 
that  a  violent  disturbance  of  the  body  soon  after 
sexual  union  may  be  a  cause  of  misplacement 
of  the  ovum.  Burdach  mentions  instances  of 
this  kind  :  one  of  a  cow  gored  by  the  horns  of 
another  soon  after  copulation,  and  two  instances 
of  the  human  female  in  which  sudden  fright 
in  the  same  circumstances  was  followed  by 
ovarian  conception.* 

In  endeavouring  to  apply  such  mechanical 
explanations,  we  ought  not  to  forget  that  in  by 
far  the  greater  number  of  cases  sudden  motion 
does  not  appear  to  disturb  the  natural  perform- 
ance of  all  those  actions  by  which  the  ovum  is 
securely  lodged  in  the  uterus  in  the  natural 
way. 

Circumstances  influencing  the  liability  to 
conception. — The  circumstances  which  influence 
the  liability  of  the  female  to  conception  are  so 
various  and  so  little  determined  that  our  re- 
marks on  this  subject  must  be  very  short. 

The  healthy  condition  of  the  female  is  of 
course  an  important  circumstance  in  reference 
to  conception,  but  we  do  not  know  in  how  far 
a  robust  constitution  or  high  state  of  health  is 
favourable  or  the  reverse  to  the  occurrence  of 
conception.  Some  women,  it  would  appear, 
(perhaps  those  of  a  spare  habit  of  body  and 
languid  powers  of  constitution)  are  most  liable 
to  fall  with  child  when  in  their  strongest  and 
best  state  of  health,  while  weakness  in  others 
seems  to  induce  conception.  Among  animals 
it  is  known  that  high  feeding  sometimes  pre- 
vents pregnancy,  and  the  same  is  the  effect  of 
the  opposite  extreme  of  starvation. 

The  regularity  of  the  menstrual  discharge  is 
one  of  the  most  important  circumstances  which 
favours  the  liability  of  women  to  conception  ; 
perhaps  more  from  its  being  an  indication  of 
the  general  healthy  state  of  the  generative  or- 
gans than  from  any  influence  exerted  by  the 
menstrual  change  itself.  Many  circumstances, 
however,  seem  to  render  it  probable  that  women 
are  more  liable  to  conception  within  a  few  days 
after  the  cessation  of  the  menstrual  flow  than  at 
any  other  period  of  the  interval,  and  accordingly 
there  are  many  accoucheurs  who  regulate  their 
calculations  of  the  time  of  birth  from  this  cir- 
cumstance, dating  the  commencement  of  utero- 
gestation  from  a  period  within  a  week  after  the 
cessation  of  the  last  menstrual  discharge.  We 
do  not  know  with  certainty  upon  what  circum- 
stances this  influence  of  the  menstrual  function 
depends ;  but  it  seems  reasonable  to  suppose 
that  it  is  connected  with  that  state  of  excitement 
and  sanguineous  congestion  in  the  ovaries  and 

*  See  Lallemand's  Observat.  Patholog.  1818, 
and  Diet,  des  Scien.  Med.  xix.  ;  also  Grasmeyer 
de  conceptu  et  fecundatione  humana,  1789. 


GENERATION. 


457 


rest  of  the  generative  organs  which  usually  at- 
tend on  menstruation.  There  seems  to  be  very 
little  reason  to  believe,  as  some  do,  that  there 
is  a  greater  than  ordinary  liability  to  concep- 
tion immediately  before  the  commencement  of 
menstruation. 

Lactation  in  the  greater  number  of  women 
prevents  conception  for  a  time,  generally  for 
from  six  months  to  a  year,  but  in  other  women 
seems  to  have  no  effect. 

It  is  very  obvious  that  the  state  of  mind  of 
the  female  has  very  little  to  do  with  conception, 
as  it  is  well  known  that  conception  *  occurs 
where  there  is  no  love,  no  desire,  in  pain,  in 
sleep,  and  in  the  state  of  insensibility;  and  it  is 
equally  well  established  that  sexual  feelings 
are  not  necessary  for  the  occurrence  of  concep- 
tion, although  it  is  possible  that  they  may  in 
some  instances  indirectly  assist.  It  is  worthy  of 
remark  that  there  are  examples  of  individuals 
of  opposite  sex  whose  marriage  has  been  barren, 
both  having  had  children  with  others. 

Signs  of  recent  conception  in  woman. — Before 
concluding  the  subject  of  the  changes  in  the  in- 
ternal generative  organs  of  the  female  which 
follow  fruitful  sexual  union,  let  us  recapitulate 
shortly  the  principal  circumstances  which  may 
be  considered  as  evidence  of  conception  having 
recently  occurred  in  the  human  female. 

In  the  first  place,  there  is  no  one  point  of 
evidence  which  is  conclusive  in  the  early  period 
of  gestation  excepting  the  finding  the  ovum  or 
foetus ;  and  here  we  must  be  on  our  guard 
against  confounding  the  mole,  or  such  pro- 
ductions which  occur  in  the  virgin,  with  the 
true  ovum.  The  other  signs  of  conception 
afford  little  satisfactory  evidence  singly,  though 
they  are  important  when  several  are  conjoined. 

The  signs  of  conception  may  be  distin- 
guished into  those  which  in  some  measure 
affect  the  whole  system,  which  may  be  called 
constitutional  or  general,  and  those  which  are 
more  strictly  local,  or  affect  principally  the 
generative  organs. 

The  more  general  signs  are — • 

1.  The  interruption  of  the  menstrual  flow  at 
the  usual  period  when  there  is  no  other  obvious 
cause  for  it. 

2.  Fulness  and  enlargement  of  the  breasts, 
and  vascularity  of  the  areola  surrounding  the 
nipple. 

3.  Derangement  of  the  functions  of  the 
stomach;  frequent  nausea  and  even  vomiting, 
especially  in  the  morning,  with  depraved  ap- 
petite, headache,  &c. 

4.  An  accelerated  pulse,  and  some  febrile 
symptoms. 

The  local  signs  are — 

1.  A  slight  enlargement  and  increased  vas- 
cularity of  the  uterus. 

2.  The  closure  of  the  mouth  and  cervix  by 
a  peculiar  viscid  secretion. 

3.  The  existence  of  the  commencing  decidua 
or  substance  from  which  that  membrane  is 
formed. 

•  See  the  amusing  speculations  of  the  phrenolo- 
gists on  this  subject. 
VOL.  II. 


4.  A  vascular  condition  of  the  ovary,  with 
very  much  enlarged  vesicles,  a  ruptured 
vesicle  or  corpus  luteum,  and  an  increased 
vascularity  or  enlargement  of  the  Fallopian 
tubes. 

Such  local  signs  can  only  be  obtained  by  the 
examination  of  the  body  after  death.  When 
the  greater  number  of  them  co-exist  and  have 
been  attended  with  the  more  general  con- 
stitutional signs,  there  is  strong  presumptive 
evidence  of  conception  having  occurred.  But 
nothing  short  of  the  appearance  of  the  child 
either  passed  in  abortion  or  found  after  death 
would  entitle  us  to  conclude  witli  certainty 
that  conception  had  taken  place,  until  those 
more  obvious  signs,  which  are  found  after  the 
period  of  quickening,  make  their  appear- 
ance. 

§  2.  As  regards  the  male  organs. 

Fecundation. — In  continuing  the  detail  of 
the  phenomena  which  accompany  or  succeed  to 
fruitful  sexual  union,  we  come  next  to  the  con- 
sideration of  the  process  of  fecundation.  We 
shall  begin  this  subject  by  a  sketch  of  the 
nature  and  properties  of  the  product  of  the 
male  generative  organs,  viz.  the  seminal  or 
spermatic  fluid,  and  afterwards  state  the  more 
important  facts  which  appear  to  throw  light 
upon  the  mechanism  of  the  remarkable  in- 
fluence exerted  by  that  fluid  on  the  ovulum 
produced  by  the  female. 

Properties  of  the  seminal  fluid. — The  se- 
minal product  of  most  animals  is  a  whitish 
fluid,  which  to  the  naked  eye  appears  homo- 
geneous or  nearly  so ;  but  in  the  human  spe- 
cies and  some  of  the  higher  animals,  the 
seminal  fluid  or  substance,  ejaculated  from 
the  male  organs  during  sexual  union,  con- 
sists of  two  parts  of  different  consistence  and 
appearance ;  in  the  human  species,  the  one 
being  of  a  pale  milky  colour  and  more  fluid, 
the  other  clearer,  semi-transparent,  and  more 
of  the  consistence  of  thick  mucilage. 

The  seminal  product  is  derived  from  several 
sources.  A  part  comes  directly  from  the  tes- 
ticle, some  is  discharged  from  the  vesiculaa 
seminales,  and  with  the  fluid  from  these 
sources  is  mixed  at  the  time  of  emission  a 
certain  quantity  of  the  product  of  the  secre- 
tion of  the  prostate  body  and  Cowper's  glands : 
but  it  is  by  no  means  well  ascertained  from 
which  of  these  organs  the  two  kinds  of  sub- 
stance above  alluded  to  are  respectively  de- 
rived. The  more  fluid  and  milky  portion  is 
first  ejected ;  the  gluey  or  clear  mucilaginous 
parts,  frequently  collected  into  small  hard 
masses,  are  more  abundant  in  the  portion 
which  is  last  emitted. 

Several  circumstances  render  it  highly  pro- 
bable that  a  considerable  quantity  of  the  fluid 
emitted  during  sexual  union  is  derived  directly 
by  secretion  from  the  testicle.  With  a  view 
to  the  illustration  of  this,  De  Graaf  performed 
the  experiment  of  tying  the  spermatic  ducts 
of  a  dog  immediately  before  coition,  and  found, 
on  examining  them  afterwards,  that  they  were 
much  distended  by  the  accumulation  of  semi- 
nal fluid  in  the  part  of  the  vasa  deferentia  in- 

2  H 


458 


GENERATION. 


tervening  between  the  ligature  and  the  testicle. 
It  may  be  remarked,  however,  there  are  no 
vesiculae  seminales  or  reservoirs  of  semen  in  the 
dog,  and  the  result  of  such  an  experiment  can 
hardly  with  justice  be  applied  to  the  human 
species.  On  the  other  hand,  it  may  be  re- 
marked that  in  man,  while  the  testicle  con- 
tinually secretes  a  small  quantity  of  semen, 
and  probably  a  larger  quantity  during  venereal 
excitement,  it  is  obvious  that  the  vesiculas 
seminales  serve  as  reservoirs  in  which  the 
seminal  fluid  accumulates ;  for  when  in  the 
dead  body  fluids  are  thrown  into  the  vas  de- 
ferens, they  pass  into  the  seminal  vesicle  of 
the  same  side  and  distend  it  before  issuing  by 
the  orifice  leading  into  the  urethra.  .The  se- 
minal fluid  after  being  secreted  probably 
follows  in  the  living  body  the  same  course ; 
and  from  this  circumstance  as  well  as  the 
suddenness  of  emission,  it  is  reasonable  to 
infer  that  the  greater  part  of  the  ejaculated 
semen,  though  formed  in  the  testicles,  comes 
in  man  immediately  from  the  seminal  vesicles. 

The  seminal  vesicles  we  may  suppose  then 
always  to  contain  a  certain  quantity  of  seminal 
fluid  in  the  state  of  health.  The  accumu- 
lation of  semen  in  these  vesicles  relieves  the 
pressure  which  otherwise  would  distend  too 
much  the  secretory  and  excretory  ducts  of  the 
testicle,  and  the  seminal  vesicles  are  them- 
selves relieved  either  by  the  sudden  evacuation 
of  their  contents  from  time  to  time,  or  by  the 
gradual  absorption  of  the  seminal  fluid  by  the 
absorbents  or  bloodvessels.'* 

There  is  also  reason  to  believe  that  the 
mucous  lining  of  the  seminal  vesicles  secretes 
a  mucous  fluid  which  is  mixed  with  the 
prolific  product  of  the  testicles.  Tn  some 
animals,  indeed,  the  vesiculae  seminales  open 
separately  from  the  vasa  deferentia  and  dis- 
charge by  their  excretory  duct  a  fluid  peculiar 
to  themselves. 

The  impotence  caused  by  castration  or  by 
the  ligature  of  the  spermatic  vessels  suffici- 
ently proves,  that  the  testicles  are  the  only 
source  of  that  part  of  the  emitted  fluid  upon 
which  the  fecundating  power  depends. 

The  properties  of  the  fluid  supposed  to  be 
derived  from  the  prostatic  body  and  Cowper's 
glands  have  not  been  satisfactorily  examined. 

The  quantity  of  the  seminal  fluid  emitted  du- 
ring sexual  union  varies  in  man  from  one  to  two 
or  three  drachms.  The  seminal  vesicles  are  not, 
however,  emptied  at  one  emission,  and,  accord- 
ing to  Haller,  when  by  repetition  this  comes  to 
be  the  case,  two  or  three  days  are  required  in 
man  to  fit  them  again  for  reproduction  by  a 
new  supply  of  fluid. 

Chemical  properties  of  the  spermatic  fluid. — 
On  cooling  immediately  after  emission,  the 
seminal  fluid  jellies  slightly,  but  in  twenty  or 
twenty-five  minutes  it  becomes    more  fluid 

*  This  absorption  of  semen  into  the  general  cir- 
culation is  conceived,  not  perhaps  on  very  sufficient 
grounds,  to  cause  some  of  the  peculiarities  of  the 
male  animal  at  the  time  of  breeding ;  to  render 
the  flesh  rank  and  unfit  for  eating  ;  more  readily 
putrescent,  &c. 


than  at  first, — a  change  which  does  not  appear 
to  depend  upon  the  absorption  of  moisture  from 
the  atmosphere,  as  its  weight  is  diminished 
rather  than  increased. 

The  chemical  properties  of  the  seminal  fluid 
have  been  examined  in  man  and  several  ani- 
mals. It  is  generally  considerably  heavier 
than  water,  has  a  peculiar  odour,  which  in- 
creases on  keeping,  is  alcaline  from  the  first, 
and  gives  off  ammonia  when  heated.  Left  at 
rest  for  some  time,  it  deposits  crystals  of  phos- 
phate of  lime-. 

According  to  the  analysis  of  Vauquelin 
human  seminal  I  uid  consists  of  the  following 
ingredients : — 

Water   90 

Animal  mucus    6 

Free  soda    1 

Phosphate  of  lime   3 

Peculiar  animal  principle   — 

100 

In  the  spermatic  fluid  of  the  horse,  Las- 
saigne  has  detected,  besides  the  above-men- 
tioned ingredients,  the  following  substances  : — 
Muriates  of  potassa  and  soda, 
Phosphates  of  lime  and  magnesia, 
Peculiar  animal  matter  called  spermatine. 
The  milt  of  fishes,  particularly  that  of  the 
carp,  analysed  by  Fourcroy  and  Vauquelin, 
contains — 

An  oily  and  saponaceous  matter, 

Gelatine, 

Albumen, 

Muriate  of  ammonia, 
Phosphate  of  lime, 

 of  magnesia, 

 of  potassa, 

  of  soda. 

Phosphorus  in  such  quantity  as  to  emit 
light  in  the  dark. 

The  semen  is  fluid  in  almost  all  animals. 
In  some  of  the  lower  animals  it  is  not  so,  but 
granular  and  crumbling.  In  the  greater  num- 
ber of  animals  the  fluid  is  of  a  white  milky 
appearance  and  thinner  consistence  than  in 
man,  presenting  in  fishes  the  appearance  of  an 
emulsion  of  yolk  of  egg  in  milk. 

In  respect  to  its  mode  of  discharge  there 
are  also  many  varieties  dependent  on  the 
structure  of  the  generative  organs.  In  the 
lowest  animals  the  testicle  alone  exists  of  the 
genital  organs,  and  the  secretory  apparatus 
of  this  organ  possesses  a  remarkably  simple 
structure,  consisting  in  many  of  a  number 
of  cceca  or  elongated  follicles  which  pour 
the  product  of  their  secretion  into  a  com- 
mon duct.  In  the  cuttle-fish  a  very  curious 
modification  exists  in  the  mode  of  discharge 
of  the  seminal  fluid ;  it  being  inclosed  in 
small  parcels  in  long-shaped  transparent  firm 
cases,  somewhat  like  small  phials.  These 
cases  are  about  three  quarters  of  an  inch  in 
length,  and  are  formed  in  the  course  of  the 
vasa  deferentia  by  an  apparatus  specially  pro- 
vided for  the  purpose:  they  are  stopped  at 
one  extremity,  and  at  the  other  are  closed  by 


GENERATION. 


459 


a  lid  somewhat  like  the  cork  of  a  phial,  be- 
tween which  and  the  main  body  of  the  case  a 
spiral  spring  is  interposed,  so  contrived  that 
when  the  case  is  immersed  in  water  the  spring 
expands,  forces  off  the  top  of  the  case,  and 
allows  the  seminal  fluid  to  issue  from  the 
interior. 

We  must  refer  to  the  anatomical  articles  for 
an  account  of  the  varieties-  of  structure  of  the 
male  generative  organs  in  different  animals. 
In  some  of  those  in  which  the  vesiciila;  semi- 
nales  are  wanting,  as  in  the  familiar  example 
of  the  dog,  copulation  is  necessarily  longer 
than  in  others.  Very  little  is  known  as  to 
the  uses  of  the  prostatic  body  or  Cowper's 
glands.    See  Generation,  Organs  of.- 

Spermatic  animalcules. — The  most  reinark-< 
able  circumstance  undoubtedly  which  is  known 
respecting  the  spermatic  fluid,  is  the  almost 
constant  existence  in  it  of  an  immense  number 
of  minute  moving  bodies  of  the  nature  of  In- 
fusorial animalculae, —  the  well-known  and 
celebrated  spermatic  animalcules,  which,  since 
the  time  of  their  first  discovery  in  1677,  have 
excited  the  curiosity  and  speculative  fancy  of 
many  naturalists.* 

The  spermatic  animalcules  have  been  found, 
at  one  time  or  other,  in  the  semen  of  almost  all 
the  animals  in  which  they  have  been  sought 
for,f  but  at  that  period  of  their  life,  and  in  that 
season  of  the  year  only,  when  the  animals  to 
which  they  belong  are  fit  for  propagation. 
They  are  diminished  in  number,  or  even  en- 
tirely disappear,  after  very  frequent  emission 
of  the  seminal  fluid.  They  almost  always 
exist  in  the  fluid  secreted  by  the  testicles,  and 
very  often  in  that  of  the  seminal  vesicles,  into 
which  they  have  doubtless  been  introduced 
along  with  the  fluid  of  the  testicles. 

From  these  circumstances,  as  well  as  others 
to  which  we  shall  afterwards  advert,  there  is 
good  reason  to  believe,  that  the  existence  of 
seminal  animalcules  in  the  male  product  is  in 
some  way  or  other  intimately  connected  with 
the  integrity  of  its  fecundating  property ;  if  not, 

*  Haller  states  as  his  conviction,  that  Ludwig 
Hamm  (then  a  student  at  Leyden)  -was  the  first 
discoverer  of  the  seminal  animalcules  in  August  of 
1677.  Leeuwenhoek  claimed  the  merit  of  having 
made  the  discovery,  in  November  of  the  same 
year,  and  in  1678,  Hartsoeker  published  an  account 
of  them,  professing  to  have  seen  them  as  early  as 
in  1674.  A  great  deal  has  since  been  written  re- 
garding them.  Needham,  Buffon,  Der  Gleichcn, 
Spallanzani,  Prevost  and  Dumas,  and  Wagner, 
may  be  mentioned  as  those  who  have  devoted 
most  attention  to  these  curious  little  animals.  Our 
remarks  are  taken  chiefly  from  the  investigations 
of  the  three  last  authors,  as  well  as  from  original 
observations. 

t  The  class  of  fishes  are  stated  by  Messrs.  Pre- 
vost and  Dumas  to  form  an  exception  to  this 
remark,  these  observers  not  having  been  able  to 
discover  any  seminal  animalcules  in  the  seminal 
fluid  of  fishes  ;  but  they  are  stated  to  have  been 
seen  by  older  authors  (see  Hallcr's  Elementa,  vol. 
vii.  p.  521);  and  from  the  latest  investigations  it 
appears  that  they  exist,  though  of  a  form  different 
from  the  spermatic  animalculae  of  most  other  ani- 
mals. The  author  has  seen  them  very  clearly  in 
the  seminal  fluid  of  the  Perch,  and  one  or  two 
other  fishes.    See  Fig.  51,  p.  112,  vol.  ii. 


as  some  are  inclined  to  hold,  the  essential  cause 
of  it. 

The  form,  appearance,  and  size  of  the  semi- 
nal animalcule  are  different  in  almost  every 
different  animal,  and  in  each  species  of  the 
more  perfect  animals  the  kind  of  animalcule 
seems,  like  that  of  Entozoa,  to  be  constant  and 
determinate.  While,  therefore,  these  little  crea- 
tures, by  their  minute  size  and  their  general 
structure  and  appearance  (so  far  as  these  are 
known),  are  distinctly  animals  of  the  infusorial 
kind,  their  residence  in  other  living  animals 
entitles  them  to  be  classed  among  the  Entozoa. 
Baer  considers  them  as  most  nearly  allied  to 
the  Cercaria  among  the  Infusoria,  and  gives 
them  the  very  appropriate  name  of  Sperma- 
tozoa. ," , 

In  what  we  have  hitherto  said  of  the  seminal 
animaicules,  we  have  drawn  our  description 
principally  from  what  has  been  observed  in 
quadrupeds  and  birds,  but  they  differ  consi- 
derably from  these  in  some  of  the  inferior 
animals.  Czermak*  holds  that  these  various 
forms  may  be  referred  to  three  principal  heads, 
viz. : — 

1 .  Cephaloidea,  merely  rounded  bodies  with- 
out tails,  existing  in  fishes  and  some  Annelida. 

2.  Uroidea,  thread-like,  in  Mollusca,  Am- 
phibia, and  some  birds. 

3.  Cephal-uroidea,  consisting  of  a  globular 
and  a  tail  part,  in  Mammalia,  Birds,  and  In- 
sects. /^^-  ' — 

The  first  of  thesif  ki/Sds  of  Spermatozoa  are 
like  the  Monades  among  Infusoria,  the  second 
resemble  the  Vibriones,  and  the  third,  as  has 
been  already  remarked,  the  Cercaria, 

It  is  important  to  remark  that,  in  so  far  as 
has  as  yet  been  ascertained,  the  form  and  size 
of  the  spermatic  animalcules  do  not  bear  any 
intimate  relation  to  the  animal  in  which  they 
exist,  nor  to  the  ova  of  the  female.  In  respect 
of  form,  Messrs.  Prevost  and  Dumas  state  that 
the  head  is  usually  of  a  round  lenticular  shape 
in  quadrupeds,  while  in  most  birds  it  is  of  a 
long  oval  shape;  but  in  some  birds  the  form  is 
the  same  as  in  most  quadrupeds.  The  semi- 
nal animalcules  present  nearly  the  same  ap- 
pearance in  man  and  in  the  dog.  Various 
marking's  are  represented  in  the  cephalic  por- 
tion of  the  animalculae  of  some  quadrupeds  by 
Messrs.  Prevost  and  Dumas,  but  these,  we 
are  inclined  to  believe,  are  not  constant,  and 
are  appearances  which  have  arisen  from  acci- 
dental circumstances. 

In  respect  to  size,  there  appears  to  be  still 
a  greater  want  of  correspondence.  The  semi- 
nal animalculae  are  said  not  to  be  larger  in  the 
whale  than  in  the  mouse.  They  are  very  much 
larger  in  Insects,  Mollusca,  and  others  of  the 
lower  animals  than  in  Man.  In  the  snail  they 
are  fifty-four  times  longer  than  in  the  dog,  and 
considerably  larger  in  the  mouse  than  in  the 
horse  >. 

The  following  table  exhibits  approximatively 
the  sizes  of  the  spermatic  animalculae  of  some 


*  Beytrage  zu  der  Lehre  von  der  Spermatozoen, 
Wien,  1833. 

2  II  2 


460 


GENERATION, 


of  the  more  common  animals  in  parts  of  a 
line:*— 

Parts  of  a  line. 

Helix  pomatia  -410 

Lymneas  stagnalis  -300 

Aquatic  Salamander  -200 

Viper  -050 

Polecat  x 

Guinea-pig  1 

Mouse    V  -040 

Linnet   1 

Sparrow  J 

Hedgehog  I 

Anguis  fragilis  S 

Bull  -028 

a^::::::::::::::::::::::1-^ 

Goat  ~\ 

^::::::::::::::::::::\-::\^ 

Rabbit   ) 

Common  fowl  -016 

Frog  -013 

D°g  ]  -008 

Man  (according  to  Der  Gleichen)  S 

Man  (according  to  BufTon)  -006 

Gruithuisen  states  that  he  has  observed  the 
seminal  animalcules  to  propagate  by  division 
of  their  bodies,  or  fissiparous  generation.  But 
we  are  far  from  attaching  implicit  faith  to  all 
that  has  been  stated  even  as  matter  of  observa- 
tion regarding  these  bodies. 

We  ought  not  to  omit  in  this  place  to  state 
another  and  a  different  view  which  has  recently 
been  taken  of  the  nature  of  the  moving  particles 
of  the  semen  ;  we  mean  that  of  G.  Treviranus, 
who,  founding  chiefly  upon  observations  made 
by  himself  in  the  lower  animals,  as  Mollusca 
and  Insects,  adopted  the  opinion  that  these 
particles  are  not  independent  animals,  but  ana- 
logous in  their  structure  and  properties  to  the 
fibrils  and  particles  occurring  in  the  pollen  of 
plants.  Their  motion  he  seems  to  regard  as  of 
the  same  kind  with  that  discovered  by  R.  Brown 
to  exist  in  infusions  of  these  and  oilier  minute 
floating  particles,  and  not  as  of  an  animal  or 
spontaneous  kind.  He  deduces  this  conclu- 
sion principally  from  the  alleged  observation 
that  the  motion  of  the  so-called  animalcules  is 
not  the  same  as  that  of  ordinary  Infusoria,  but 
differs  from  it  in  this  respect,  that  it  is  simply 
vibratory  and  constant,  and  not  interrupted  by 
any  of  those  stops  or  pauses  and  changes  from 
place  to  place  which  are  held  to  indicate  spon- 
taneity in  the  motions  of  Infusoria.f 

Some  of  the  facts  already  stated  by  us  shew 
the  fallacy  of  the  opinion  of  Treviranus.  Baer, 
who  regards  the  Spermatozoa  as  distinct  living 
animals,  holds  that  Treviranus  has  observed 
only  an  imperfect  condition  of  the  animalcule, 
and  states  in  the  work  of  BurdachJ.  some  addi- 
tional observations  of  his  own  made  in  the 


snail,  which  promise,  when  pursued  further,  to 
remove  some  of  the  difficulties  respecting  the 
nature  of  these  bodies.  Baer  states  that  he  has 
observed  the  head  and  tail  parts  to  become 
separated  from  one  another,  and  both  these 
parts,  but  especially  the  tail,  to  move  about 
after  separation.  Baer  has  observed  also  that 
there  are  various  stages  of  formation  and  change 
of  the  seminal  animalcule,  during  which  not 
only  their  form  but  also  their  motions  undergo 
remarkable  alterations,  and  he  supposes  that 
Treviranus  must  have  observed  the  spermatic 
animalcule  of  the  snail  and  mussel  in  one  of 
these  stages  only.  Observations  made*  by 
the  author  of  this  article  and  by  Dr.  Sharpey  in 
the  frog,  seem  to  bear  upon  this  point,  and  to 
be  in  some  degree  confirmatory  of  the  view 
given  by  Baer.  We  have  almost  invariably 
found,  in  observing  the  seminal  fluid  of  the 
frog  in  the  spring  or  summer,  that  the  animal- 
cules contained  in  it  are  not  of  the  kind  de- 
scribed by  authors  in  this  animal,  viz.  with 
both  head  and  tail,  but  of  the  thread-like  form 
only.  These  were  collected  in  bundles  in  the 
thick  part  of  the  fluid,  and  generally  moved 
with  a  continued  vibration  such  as  we  have 
previously  described.  In  the  thin  part  of  the 
fl  nid  there  were  a  few  round-shaped  or  monad- 
like infusoria.  Occasionally  it  happened  that 
when  water  was  added  to  the  thick  part  of 
the  fluid,  and  the  bundles  of  the  thread-like 
bodies  were  artificially  broken  down,  some  of 
them  moved  progressively  through  the  fluid  by 
the  undulatory  riggling  of  one  of  the  extremi- 
ties ;  and  during  their  motion  we  were  surprised 
to  see  some  of  those,  which,  when  at  rest,  ap- 
peared to  be  destitute  of  any  cephalic  part,  fre- 
quently assume  the  appearance  of  a  head.  This 
phenomenon  we  remarked  to  be  owing  to  the 
circumstance  that  the  end  by  which  the  animal- 
cule moved  forward  was  bent  backwards  on  the 
middle  of  the  body,  so  as  at  one  time  to  give 
exactly  the  tadpole-like  appearance  which  is 
represented  as  a  head  in  their  plates  by  Messrs. 
Prevost  and  Dumas.  There  could  be  no  doubt 
that  this  was  the  case,  for  in  some,  in  which  at 
one  time  the  end  was  so  closely  joined  to  the 
body  that  it  could  not  be  seen,  at  another  it 
loosened  from  it,  and  the  thread-like  animal- 
cule still  continued  to  progress  in  the  fluid 
with  its  curve  forwards,  and  the  two  ends  (of 
unequal  length)  floating  separate  and  loose. 
The  author  has  observed  nearly  the  same  phe- 
nomena in  the  spermatic  fluid  of  the  pigeon. 
Lastly,  the  observations  of  R.  Wagner  on  the 
spermatic  fluid  of  the  Guinea-pig  seem  to  prove 
more  decidedly  than  any  of  the  previously  men- 
tioned facts  that  the  spermatic  infusoria  are 
subject  to  remarkable  changes  of  form  at  dif- 
ferent periods,  and  that  they  even  go  through  a 
regular  gradation  of  development. 

The  discrepancy  of  these  observations  makes 


*  This  table  is  taken  principally  from  the  mea- 
surements of  Prevost  and  Dumas  given  in  their 
excellent  account  of  the  seminal  animalcules  pub- 
lished in  the  .Annales  des  Sciences  Naturelles. 

t  See  a  paper  in  Tiedemann's  Zeitschrift,  vol.  v. 
part  2,  1835. 

f  Vol.  i.  second  edition. 


*  These  observations  were  made  five  years  before 
the  publication  of  this  article.  For  further  infor- 
mation respecting  the  Spermatozoa  we  refer  the 
reader  to  the  articles  Entozoa  and  Semen  ;  in  the 
last  of  which  Mr.  Wagner,  who  has  investigated 
their  nature  with  great  success,  will  fully  explain 
his  views. 


GENERATION. 


461 


it  apparent  that  we  ought  in  the  present  state  of 
our  knowledge  to  be  very  cautious  in  making 
any  general  conclusion  regarding  the  nature  of 
the  spermatic  animalcules.  It  appears  to  be 
fully  proved  that  some  such  animalcules  always 
exist  in  the  seminal  fluid  of  animals  when  they 
are  fit  for  propagation  ;  but  it  is  by  no  means 
certain  that  they  belong  exclusively  to  the  fluids 
which  are  the  product  of  secretion  in  the  tes- 
ticle, for  animalcule  very  similar  to  them  in 
general  appearance  and  in  motions  are  to  be 
found  in  various  other  fluids  and  organs  of 
animals.  In  all  those  parts  of  the  body  in 
which  mucous  secretions  are  accumulated,  ani- 
malcule are  formed,  and  in  some  of  the  lower 
animals  the  Cercarie  of  intestinal  mucus  are 
hardly  to  be  distinguished  from  the  animal- 
cule of  their  seminal  fluid. 

Nor  is  it  well  ascertained  that  these  animal- 
cules belong  exclusively  to  the  fluid  of  the  tes- 
ticle, and  do  not  sometimes  occur  in  the  secre- 
tions of  other  parts  of  the  generative  organs. 
They  exist  no  doubt  frequently  in  the  seminal 
fluid  of  the  testicle,  but  some  recent  observa- 
tions seem  to  shew  that  they  are  frequently 
imperfect  in  the  fluid  of  that  organ,  and  that  in 
some  animals  at  least  they  are  not  fully  formed 
and  do  not  acquire  their  powers  of  active  mo- 
tion till  some  time  after  the  seminal  fluid  is 
secreted,  and  when  it  has  passed  from  the  tes- 
ticle into  other  parts  of  the  generative  organs. 
On  this  account  some  hold,  and  with  good 
reason,  that  they  are  to  be  regarded  as  the  pro- 
duct of  reciprocal  changes  of  the  ingredients  of 
the  seminal  fluid  on  one  another,  rather  than  as 
secreted  along  with  that  fluid  directly  from  the 
bloodvessels  of  the  testicle,  as  others  have  sup- 
posed. 

In  conclusion,  we  would  remark  that  in 
regard  to  the  seminal  animalcule  having  both 
the  body  and  tail,  such  as  those  that  may  be 
seen  in  the  dog,  cat,  rabbit,  or  other  quadru- 
peds, and  which  were  described  by  the  dis- 
coverers and  early  observers  of  the  seminal 
animalcule,  no  one  who  has  had  an  oppor- 
tunity of  observing  them  carefully  with  a  good 
lens  magnifying  three  or  four  hundred  diame- 
ters can  doubt  for  a  moment  that  they  bear  a 
close  resemblance  to  some  of  the  Infusoria,  and 
that  both  from  their  structure  and  motions  they 
are  with  as  much  justice  as  the  Infusoria  to  be 
regarded  as  distinct  animal  beings.  With  re- 
gard to  the  other  kinds  above  mentioned,  or  the 
changes  they  may  undergo  in  different  stages 
of  their  existence,  farther  investigations  appear 
necessary  to  enable  us  to  form  an  opinion. 

Although  the  spermatic  animalcules,  like 
other  Entozoa,  are  formed  only  in  living  ani- 
mals and  may  be  regarded  as  dependent  for 
life  on  those  animals  in  which  they  occur,  yet 
they  retain  their  life  for  a  time  after  they  leave 
the  body.  Thus  the  spermatic  animalcules  of 
the  Polecat,  which  Prevost  and  Dumas  ob- 
served with  much  attention,  continued  to  move 
for  fifteen  or  twenty  minutes  on  the  object- 
stand  of  the  microscope  ;  and  these  experimen- 
ters state  that  when  the  seminal  fluid  is  allowed 
to  remain  in  the  genital  organs,  the  animalcules 


continue  to  live  for  fifteen  or  eighteen  hours 
after  the  death  of  the  animal.  Their  motions 
cease  instantly  when  a  strong  electric  spark  is 
passed  through  the  fluid  containing  them. 

Immediately  after  the  discovery  of  the  semi- 
nal animalcules,  they  were  made  the  subject  of 
very  fanciful  hypotheses,  and  were  conceived  to 
throw  quite  a  new  light  upon  some  of  the  ob- 
scure parts  of  the  generative  process.  To  the 
supporters  of  the  theory  of  pre-existing  germs, 
their  discovery  opened  up  the  prospect  of  being 
able  to  trace  backwards  one  link  more  than  had 
previously  been  done  in  the  chain  of  life  which 
connects  the  parent  and  offspring.  By  some 
they  were  considered  as  the  cause  of  sexual  en- 
joyment or  venereal  propensities.  By  others, 
the  animalcule  were  held  to  be  of  different 
sexes,  and,  according  as  one  or  other  gained  the 
egg  during  fecundation,  to  give  rise  to  a  male 
or  female  offspring,  and  thus  to  determine  its 
sex.  They  have  been  supposed  by  others  to 
form  the  first  rudiments  of  the  foetus  or  lay 
the  foundation  in  the  germ  of  the  egg  from 
which  the  offspring  is  afterwards  developed, 
and  fecundation  has  thus  been  resolved  into 
the  simple  passage  of  a  seminal  animalcule 
into  the  germinal  part  of  the  egg;  and  finally, 
one  or  two  of  the  most  fanciful  of  such  dream- 
ing physiologists  have  (as  we  had  occasion  to 
remark  at  a  former  part  of  our  article)  not  failed 
to  perceive  on  a  sufficiently  minute  inspection 
of  the  animalcule,  that  it  already  possessed 
all  the  organs  belonging  to  the  mature  con- 
dition of  the  animal  in  the  seminal  fluid  of 
which  it  existed ;  compressed  no  doubt  into 
a  very  small  space,  but  from  which  it  was  easy 
to  suppose  the  offspring  to  be  formed  by  evo- 
lution.* 

Such  notions  require  no  refutation.  Let  us 
rather  pass  now  to  the  inquiry  of  how  far  ob- 
servation and  experiment  have  tended  to  throw 
light  upon  the  essential  circumstances  upon 
which  the  fecundating  property  of  the  seminal 
fluid  depends. 

The  nature  of  the  change  which  confers 
upon  the  egg  the  power  of  production  is  entirely 
unknown  to  us, and  we  already  remarked  towards 
the  commencement  of  this  article  that  this  action 
is  to  be  ranked  among  those  vital  operations  of 
the  animal  economy  which  are  placed  beyond 
the  reach  of  our  means  of  investigation.  We 
should  with  equal  prospect  of  success  proceed 
to  inquire  how  life  originates  and  is  maintained 
in  the  parent,  as  to  investigate  the  secret  man- 
ner of  the  transmission  of  the  vital  spark  from 
the  parent  to  the  offspring.  The  physiologist 
who  would  study  this  subject  must  therefore 
limit  his  inquiries  in  this  as  in  other  departments 
of  his  science  to  the  search  after  those  condi- 
tions or  chain  of  circumstances  which  appear 
to  be  essential  to  the  occurrence  of  the  parti- 
cular change  or  phenomenon  which  is  the 
object  of  his  investigation. 

Our  present  object,  then,  is  not  to  investigate 
the  nature  of  the  change  by  which  the  living 

*  Gaultler,  Generation  dei  Hommes  et  dea 
Animaux.    Paris,  1750. 


462 


GENERATION. 


productive  power  is  given  to  the  egg,  but  to 
endeavour  to  establish  what  are  the  essential 
conditions  of  fecundation. 

Difference  between  the  fecundated  and  unfe- 
cunduted  ovum.- — In  the  first  place,  in  reference 
to  this  subject,  it  would  be  interesting  to  know 
whether  any  material  difference  exists  between 
the  structure  of  the  fecundated  and  unfecun- 
dated  egg. 

In  the  common  fowl  we  have  seen  that  the 
whole  substance  of  the  egg,  the  yolk  and  ger- 
minal portion,  the  albumen,  shell,  and  mem- 
brane, may  be  formed  in  the  ovaries  and  oviduct, 
and  excreted  from  the  body  of  the  hen  without 
any  connection  with  the  cock  ;  but  such  an 
egg,  though  apparently  the  same  in  structure 
with  that  which  is  laid  after  connection  with 
the  cock,  when  subjected  to  the  requisite  heat, 
undergoes  none  of  the  changes  of  development 
which  incubation  induces  in  the  fecundated 
egg,  but  only  passes  into  chemical  decomposi- 
tion like  any  other  dead  animal  substance. 

Did  any  difference  of  structure  exist  between 
the  fecundated  and  unfecundated  egg,  we 
should  be  disposed  to  look  for  it  first  in  that 
part  of  the  egg  which  is  more  immediately  con- 
nected with  the  new  being,  viz.  in  its  germinal 
portion  ;  but  we  regret  to  say  that  the  investiga- 
tions of  naturalists  have  not  as  yet  pointed  out 
any  marked  difference  in  a  satisfactory  manner. 
Malpighi,  it  is  true,  long  ago  pointed  out  a 
difference  in  the  structure  of  the  cicatricula  of 
the  egg  of  the  common  fowl  which  had  had 
connection  with  the  cock,  and  those  of  the  hen 
living  single,  and  the  observations  of  this  author 
were  afterwards  confirmed  by  Prevost  and 
Dumas.  In  the  impregnated  egg  the  cicatri- 
cula is  a  well-defined  whitish  spot,  with  a  re- 
gularly formed  transparent  area  in  its  centre ; 
while  in  the  unimpregnated  egg  there  is  no  re- 
gularly shaped  transparent  area,  but  rather  a 
number  of  small  irregular  clear  spaces  scattered 
over  the  surface  of  the  cicatricula.  We  fear, 
however,  that  this  appearance  of  irregularity 
exists  as  well  in  some  eggs  that  have  been  laid 
after  connection  with  the  cock,  and  that  the 
shape  or  appearance  of  the  cicatricula  can 
scarcely  be  depended  upon  as  informing  us 
whether  an  egg  has  been  fecundated  or  not, 
since  that  appearance  is  much  influenced  by 
the  state  of  the  nucleus  or  white  matter  of  the 
yolk  situated  below  it,  as  well  as  by  the  state 
of  the  cicatricula  itself.  This  subject  is  worthy, 
however,  of  the  most  accurate  investigation,  as 
it  appears  to  offer  the  prospect  of  affording 
some  information  on  this  very  obscure  part  of 
the  generative  process. 

In  the  ovarian  ovulum,  the  vesicle  of  Pur- 
kinje,  it  will  be  recollected,  occupies  the  centre 
of  the  cicatricula  ;  and  this  vesicle  exists  in  the 
ovulum  so  long  as  it  remains  within  the  ovarian 
capsule,  whether  the  hen  have  connection  with 
the  cock  or  not.  In  the  impregnated  fowl  the 
germinal  vesicle  of  Purkinje  bursts,  and  leaves 
the  transparent  area  in  the  centre  of  the  cicatri- 
cula at  the  time  when  the  ovulum  passes  from 
the  ovarian  capsule  into  the  oviduct ;  but  it  re- 
mains to  be  known  if  the  same  is  the  case,  or 


what  phenomena  ensue  upon  the  escape  of  the 
ovulum  from  the  ovarium  in  the  fowl  which  is 
entirely  separated  from  the  cock.* 

We  do  not  know  with  certainty  what  befalls 
the  vesicle  of  Purkinje  in  the  ovulum  of  Mam- 
malia at  the  time  of  its  escape  from  the  ovarium. 
The  analogy  of  all  oviparous  animals  is  strongly 
in  favour  of  the  supposition  that  it  bursts  in  the 
same  manner.  M.  Coste  states  that  it  does  not 
burst,  and  Valentin  supports  an  opposite  view. 

While,  therefore,  we  feel  disposed  to  adopt 
the  opinion  that  the  seminal  fluid,  in  fecunda- 
ting the  egg,  operates  its  peculiar  change  chiefly 
on  the  germinal  part,  and  that  the  bursting  of 
the  germinal  vesicle  is  very  probably  connected 
with  the  change  of  fecundation,  it  must  be  ad- 
mitted that  further  observations  are  still  want- 
ing to  afford  a  satisfactory  proof  of  the  correct- 
ness of  these  hypotheses. 

Is  material  contact  of  the  semen  and  ovum 
necessary  for  fecundation  ? — No  one  has  ever 
discovered  any  of  the  seminal  fluid  within  the 
egg  :  the  most  minute  observation  does  not  de- 
tect any  appearance  of  this.  A  question  then 
naturally  presents  itself  in  reference  to  the  sub- 
ject of  our  present  inquiry,  viz.  whether  it  is 
necessary  that  a  certain  quantity  of  the  sub- 
stance of  the  seminal  fluid  should  be  brought 
into  actual  contact  with  the  egg  in  order  to 
cause  its  fecundation  ?  and  if  so,  in  what  man- 
ner and  in  what  part  of  the  female  organs  such 
contact  is  brought  about? 

Were  we  to  look  no  further  than  to  the 
manner  in  which  fecundation  is  effected  in 
many  of  the  inferior  animals,  we  might  be  in- 
duced at  once  to  form  the  opinion  that  the  mere 
contact  of  a  certain  quantity  of  the  seminal  fluid 
with  their  ova,  in  whatever  way  brought  about, 
is  all  that  is  necessary  for  producing  their  fecun- 
dation. Thus,  in  the  greater  number  of  fishes 
the  milt  or  seminal  fluid  of  the  male  is  shed 
over  the  spawn  of  the  female  after  it  is  laid  in 
water,  without  there  being  any  nearer  sexual 
intercourse;  the  fecundation  is  external  to  the 
body  of  the  female,  and  we  thus  know  with 
certainty  that  the  ova  and  the  seminal  fluid  are 
the  only  parts  immediately  concerned  in  the 
process.  The  same  is  the  case  in  the  common 
frog,  in  which  there  is  copulation ;  for  in  that 
animal,  although  the  male  and  female  remain 
united  firmly  together  during  a  longer  period 
than  any  other  kind  of  animal,  yet  this  union 
is  not  a  means  of  producing  fecundation,  but 
rather  of  promoting  the  discharge  of  unim- 
pregnated ova  from  the  generative  system  of 
the  female.  There  is  in  fact  no  true  sexual 
union  :  the  spawn  is  laid  by  the  female  un- 
fecundated, and  the  male  (separating  then  in 
general  from  the  female)  sprinkles  seminal  fluid 
on  the  ova  floating  in  water. 

External  and  artificial  fecundation. — The 
mode  of  fecundation  just  now  mentioned  sug- 

*  We  have  long  had  the  intention  of  instituting 
a  series  of  observations  comparing  the  changes  of 
the  impregnated  and  unimpregnated  ovum  in  the 
oviduct,  but  have  not  yet  had  an  opportunity,  and 
we  recommend  it  to  those  who  may  be  anxious  to 
engage  in  the  investigation  of  this  subject. 


GENERATION. 


463 


gested  to  Spallanzani*  the  ingenious  expe- 
riment of  artificial  fecundation,  which  he  first 
performed,  and  which  furnished  the  most  con- 
vincing proof  that  could  be  obtained,  that,  in 
such  animals  as  the  frog,  sexual  union  is  not 
essential  to  fecundation,  and  that,  when  the 
ova  are  ripe  and  the  seminal  fluid  of  the  suit- 
able quality,  the  mere  contact  of  the  male  and 
female  products  is  sufficient  to  confer  fertility 
upon  the  ova. 

Spallanzani  opened  very  many  female  frogs 
at  the  time  of  propagation,  but  before  they  had 
laid  any  spawn,  and  consequently  before  im- 
pregnation could  have  occurred,  and  he  satis- 
fied himself  that  the  ripest  ova  extracted  from 
the  oviduct,  and  placed  in  water,  gradually 
passed  into  putrefaction  without  undergoing 
any  of  the  changes  of  development;  while  some 
of  the  same  ova,  upon  which  he  had  sprinkled 
some  of  the  seminal  fluid  taken  from  the  body 
of  the  male,  and  placed  in  similar  vessels  of 
water,  had  tadpoles  formed  from  them  in  the 
same  manner  exactly  as  those  which  were  fe- 
cundated by  the  male  frog  itself,  f 

The  same  experiments  were  performed  by 
Spallanzani  on  toads  and  newts  with  exactly 
the  same  result. 

.  Spallanzani,  in  order  to  avoid  every  fallacy, 
allowed  the  female  to  remain  in  union  with  the 
male,  and  to  lay  her  spawn  in  the  natural  way, 
preventing  only  the  access  of  any  of  the  seminal 
fluid  of  the  male  to  the  ova,  by  tying  up  the 
hinder  part  of  the  male's  body  in  oiled  silk,  and 
these  ova  were  alike  barren,  unless  he  added  to 
them  some  of  the  seminal  fluid  in  the  artificial 
mode. 

TreviranusJ  mentions  the  performance  of  the 
experiment  of  artificial  fecundation  in  Fishes, 
viz.  on  the  spawn  of  the  Salmon,  Trout,  and 
Carp,  by  Duhamel  and  by  Jacobi.  Jacobi's 
experiments  were  repeated  by  Dr.  Walker  of 
Edinburgh  ;  and  very  recently  it  has  again  been 
performed  on  the  spawn  of  the  Tench  and 
Bleak  by  Itusconi  of  Pavia.  (Cyprinus  Tine  a 
and  Alburnus.) 

The  very  complete  series  of  experiments  of 
Messrs.  Prevost  and  Dumas§  on  the  frog- 
afford  the  most  satisfactory  confirmation  of 
those  of  the  Abbe  Spallanzani. 

The  following  appear  to  be  the  more  im- 
portant results  deducible  from  these  two  sets  of 
experiments. 

1st.  That  a  very  small  quantity  indeed  of  the 
seminal  matter  is  requisite  for  the  fecundation 
of  the  ovum. 

2d.  That  dilution  of  the  seminal  fluid  with 
water  within  certain  limits  does  not  impede, 
but  rather  is  favourable  to  its  operation. 

3d.  That  the  absorbent  power  of  the  albumi- 
nous or  gelatinous  matter  which  surrounds  the 
black  yolk  is  highly  useful  in  bringing  the 
seminal  substance  in  contact  with  the  yolk, 
where  it  is  obvious  its  effect  must  be  produced. 

*  Dissertazioni  di  fisica  animale,  &c. 

t  This  experiment  the  author  has  more  than  once 
performed  with  a  similar  result. 

t  Erscheinungen  und  Gesezte  des  Organischen 
Ijebens. 

§  Annul,  des  Sciences  Nat.  torn.  i. 


This  albuminous  covering,  corresponding  to  the 
white  of  the  bird's  egg,  possesses  the  remark- 
able property  of  absorbing  water,  somewhat 
like  gum  tragacanth,  in  a  determinate  quantity, 
and  thus  increases  greatly  in  bulk  after  being 
laid  in  water.  In  the  experiments  referred  to, 
the  absorption  of  the  water  by  the  jelly  was 
fully  demonstrated  by  the  immersion  of  the  ova 
in  coloured  water,  and  it  was  found  also  that 
the  experiment  of  artificial  fecundation  suc- 
ceeded best  when  the  ova  had  not  been  im- 
mersed in  water  for  any  considerable  time  pre- 
vious to  the  addition  of  the  seminal  fluid.  The 
fecundation  was  less  certain  the  longer  the  ova 
were  allowed  to  remain  in  water  before  the  ad- 
dition of  the  semen  ;  and  it  was  shewn  that  this 
did  not  depend  simply  on  the  length  of  time 
of  the  separation  of  the  ova  from  the  body  of 
the  parent,  by  the  fact  that  ova  taken  from 
the  oviduct  and  kept  without  moisture  re- 
tained their  susceptibility  of  being  fecundated 
for  a  much  longer  period,  as  sixteen  or  twenty 
hours. 

4th.  That  the  seminal  fluid  of  the  frog  retains 
its  fecundating  power  for  about  thirty  hours 
after  it  has  left  the  body  of  the  male. 

5th.  Attempts  were  made  by  both  the  expe- 
rimenters above  quoted  to  ascertain,  by  way  of 
experiment,  whether  the  seminal  animalcules 
are  indispensable  to  fecundation.  Spallanzani 
came  to  the  conclusion  that  the  seminal  fluid 
did  not  lose  its  peculiar  powers  although  de- 
prived of  its  animalcules,  or  although  the  ani- 
malcules were  dead ;  but  it  must  be  admitted 
that  the  means  employed  by  that  observer  to 
ascertain  the  presence  or  absence  of  the  seminal 
animalcule  were  inferior  to  those  we  possess 
in  more  recent  times.  Messrs.  Prevost  and 
Dumas,  who,  it  has  already  been  remarked, 
consider  the  animalcules  as  the  most  important 
part  of  the  seminal  fluid  in  reference  to  its 
fecundating  properties,  state  that  they  found  in 
their  experiments,  that  that  part  of  the  seminal 
fluid  which  had  been  subjected  to  a  very  careful 
filtration,  and  which  had  thus  been  wholly  de- 
prived of  its  animalcules,  had  lost  all  fecunda- 
ting power,  while  the  substance  which  remained 
in  the  filter,  and  which  was  rich  in  animalcules 
when  diluted  with  water,  possessed  the  same 
powers  of  fecundation  as  the  pure  seminal  fluid. 
We  think  this  experiment  requires  repetition 
and  some  modifications,  for  other  ingredients, 
besides  the  animalcules  of  the  seminal  fluid, 
might  be  retained  on  the  filter. 

6th.  Both  Spallanzani  and  Prevostand  Dumas 
have  attempted  to  estimate  the  quantity  of 
seminal  fluid  required  for  the  fecundation  of  a 
certain  number  of  ova,  and  the  latter  observers, 
pursuing  their  favourite  idea  to  the  utmost,  have 
even  endeavoured  to  calculate  the  number  of 
animalcules  which  are  necessary  for  the  fructi- 
fication of  one  or  more  ova.  In  Spallanzani's 
experiments  two  grains  of  the  semen  of  the 
toad  fecundated  one  hundred  and  thirteen 
ova.  Five  grains  of  semen  were  mixed  with 
eighteen  ounces  of  water;  the  point  of 
a  needle  dipped  in  this  was  made  to  touch  an 
egg  for  an  instant  and  produced  fecundation. 
The  proportion  here  might  be  estimated  as 


464 


GENERATION. 


semen  1,  to  egg  1,064,000,000.  The  addition 
of  a  larger  quantity  of  semen,  or  its  remaining 
longer  in  contact  with  the  egg,  did  not,  accord- 
ing to  Spallanzani,  render  the  fecundation  more 
complete  than  the  instantaneous  contact  of  the 
wetted  needle's  point.  Prevost  and  Dumas 
state  that  they  found  the  number  of  ova  fecun- 
dated by  a  given  quantity  of  seminal  fluid  is 
always  below  that  of  the  animalcules  which  they 
estimated  that  fluid  to  contain;  and  by  a  sim- 
ple process  of  calculation  it  was  easy  to  find 
how  many  animalcule  served  each  ovum.  A 
certain  quantity  of  seminal  fluid,  for  example, 
containing  225  animalcules,  served  to  fecun- 
date 61  only  out  of  380  ova,  to  which  it  was 
added,  so  that  each  ovum  required  about  3| 
animalculce  for  its  fecundation,  or  making 
allowance  for  a  few  of  the  animalcule  which 
went  astray  into  other  ova,  it  may  be  stated  as 
three  in  round  numbers.  It  will  be  long  before 
the  vital  processes  can  be  traced  with  the  arith- 
metical precision  displayed  in  this  calculation. 
Unfortunately  for  the  calculations  and  even  the 
observations  upon  which  they  are  founded,  one 
of  the  authors  at  a  subsequent  period  published 
the  theory  which  appears  to  have  prompted 
them  to  revive  an  old  and  fanciful  notion  that 
the  animalcule  forms  the  rudiment  of  the  new 
being.  The  animalcule,  according  to  this  hy- 
pothesis, makes  its  way  through  the  stiff  jelly 
surrounding  the  yolk,  gains  the  centre  of  the 
germinal  membrane,  and  esconces  itself  there 
in  the  very  centre  of  that  germinal  membrane, 
laying  thus  the  foundation  of  the  primitive 
streak  or  the  brain  and  spinal  marrow  of  the 
foetus  :  its  position  (which  is  always  the  same) 
being  no  doubt  determined  by  the  laws  of  po- 
larity depending  upon  the  electro-magnetic 
properties  with  which,  according  to  equally 
fanciful  theorists,  the  rudiments  of  the  new 
being  in  the  egg  are  endowed. 

Hitherto  cold-blooded  and  oviparous  animals 
only  have  been  alluded  to;  but  there  are  not 
wanting  facts  which  render  it  highly  probable 
that  in  viviparous  animals  also,  contact  of  se- 
minal fluid  with  the  ovum  is  the  essential  part 
of  the  fecundating  process.  Thus,  Spallanzani 
confined  a  bitch  for  fourteen  days  before  the 
arrival  of  heat,  and  for  twenty-six  days  after  it, 
so  that,  during  that  time,  it  could  have  had  no 
connexion  with  any  dog,  and  at  the  time  of 
the  heat  he  injected  by  means  of  a  syringe 
a  quantity  of  the  dog's  seminal  fluid  into  the 
vagina.  The  bitch  brought  forth  three  young 
exactly  at  the  usual  length  of  time  from  the 
period  of  heat;  —  an  experiment  on  artificial 
fecundation,  which  may  in  some  sort  be  said 
to  have  been  performed  in  the  human  species 
is  the  well-known  instance  in  which  John  Hun- 
ter recommended  to  a  man  affected  with  hy- 
pospadiac  malformation  of  the  urethra,  which 
rendered  intromission  of  the  seminal  fluid 
impossible,  the  injection,  by  means  of  a  sy- 
ringe, of  the  seminal  fluid  into  the  vagina, — 
an  operation  which,  it  is  related,  was  attended 
with  complete  success. 

While  these  facts  on  the  one  hand  tend  to 
shew  that  no  parts  of  the  genital  organs  and 
no  other  agents  are  concerned  in  fecundation 


excepting  the  seminal  fluid  and  the  ova,  and 
on  the  other  hand  afford  the  only  positive 
evidence  that  can  be  obtained,  that  actual  con- 
tact of  the  one  with  the  other  is  necessary  to 
induce  the  change,  they  have  appeared  unsa- 
tisfactory to  some  physiologisls,who  cling  to  the 
opinion  that,  in  quadrupeds  and  birds  at  least, 
contact  is  not  necessary,  and  that  fecundation 
may  be  effected  either  by  some  hidden  sym- 
pathy (or  concurrent  action  taking  place  in 
remote  parts)  between  the  external  and  internal 
organs  of  the  female,  or  that  this  change  may 
be  operated  by  some  imponderable  influence 
which  emanates  from  the  seminal  substance,  to 
which  the  vague  name  of  aura  seminalis  has 
been  given. 

Course  of  the  seminal  fluid  within  the female 
organs. — In  pursuing  our  examination  of  the 
alleged  evidence  upon  which  these  and  similar 
hypotheses  are  founded,  it  will  be  necessary 
to  consider  in  this  place  another  question, 
respecting  which  it  is  difficult  in  the  present 
state  of  the  inquiry  to  form  a  decided  opinion, 
viz.  whether,  on  the  supposition  of  the  seminal 
fluid  and  ova  coming  into  actual  contact,  the 
course  of  the  seminal  fluid  within  the  female 
organs  of  generation  can  in  any  instances  be 
traced,  and  in  what  part  of  these  organs  it 
may  be  supposed  to  meet  with  the  ova  and 
operate  their  fecundation. 

In  the  first  place  the  examples  of  ovarian 
conceptions,  or  rather  gestations,  have  been  ad- 
duced by  some  as  a  proof  that  fecundation 
necessarily  takes  place  in  the  ovaries  them- 
selves. But  from  what  was  said  in  a  former 
part  of  this  paper,  it  will  be  seen  that  such  a 
belief  is  founded  on  an  erroneous  view  of  the 
nature  of  these  misplaced  gestations,  as  well  as 
of  the  phenomena  which  occur  in  the  ovary 
after  conception.  There  is  no  reason  to  believe, 
we  may  repeat,  that  ova  found  developed  in 
the  neighbourhood  of  the  ovary  have  retained 
their  situation  within  the  Graafian  vesicle.  On 
the  contrary,  they  must  in  all  probability  have 
been  first  discharged  from  the  ovary  upon  the 
rupture  of  the  vesicle,  and  their  places  occu- 
pied by  corpora  lutea;  and  they  may  have 
been  fecundated  either  while  loose  in  the 
cavity  of  the  peritoneum,  or  when  they  have 
descended  some  way  in  the  Fallopian  tubes, 
and  meeting  with  the  seminal  fluid  in  the 
course  of  that  tube,  have  been  returned  to  the 
vicinity  of  the  ovary  by  some  inverted  or  un- 
natural action  of  the  parts.* 

Although,  therefore,  no  very  decided  opinion 
respecting  the  place  at  which  fecundation 
occurs  can  be  formed  from  the  observation  of 
what  are  termed  ovarian  and  tubular  gesta- 
tions, we  are  inclined  to  think  that  they  shew 

*  We  need  do  no  more  than  mention  here  a  view 
taken  by  Sir  Everard  Home  of  the  uses  of  the 
corpora  lutea,  which  he  holds  to  be  a  means  of 
bringing  the  seminal  fluid  into  contact  with  the 
ovum  of  the  Graafian  vesicle.  This  opinion  re- 
quires no  remark,  as  it  will  be  at  once  perceived 
that  it  proceeds  on  the  assumption,  shewn  to  be 
erroneous  in  a  former  part  of  this  paper,  that  the 
corpora  lutea  are  formed  before  the  rupture  of  the 
vesicles. 


GENERATION. 


465 


that  this  process  may  take  place,  in  some  in- 
stances at  least,  in  the  upper  parts  of  the  Fal- 
lopian tube,  or  even  in  the  infundibulum. 

In  the  second  place  physiologists  have  en- 
deavoured to  argue  respecting  the  place  of 
fecundation  from  the  well-known  fact  that, 
in  the  common  fowl,  turkey,  and  probably 
some  other  birds,  a  single  connexion  with  the 
male  serves  to  fecundate  more  than  one  ovum, 
as,  for  example,  in  the  common  fowl  twelve 
or  twenty  ova;  and  that, as  there  is  usually  only 
one  ovum  in  the  progress  of  descent  through 
the  oviduct  at  one  time,  we  must  conclude 
either  that  the  yolks  or  ovula  are  fecundated 
by  the  rise  of  the  seminal  fluid  to  the  ovary, 
or  that  the  seminal  fluid  remains  somewhere 
in  the  course  of  the  oviduct,  to  be  applied  to 
the  ovum  as  it  descends.  If  we  exclude  the 
notions  of  an  aura  and  sympathetic  action, 
the  former  of  the  above-mentioned  views  ap- 
pears to  us  the  most  consistent  with  the  facts 
that  have  already  come  under  our  knowledge. 
The  notion  entertained  by  Fabricius  and  others 
that  there  is  a  receptacle  for  containing  the 
seminal  fluid  in  the  oviduct  appears  to  be  in- 
correct; and  we  find  it  difficult  to  believe  that 
the  seminal  fluid  can  remain  dispersed  through 
the  oviduct,  or  confined  in  any  particular  part 
of  it  and  retain  its  power  of  fecundation,  when 
we  consider  the  manner  in  which  each  yolk 
descends  from  the  ovary  and  receives  in  its 
passage  the  various  accessory  parts  constituting 
the  albumen  and  external  coverings.  Of 
course,  in  supposing  fecundation  to  take  place 
in  the  ovary,  there  remain  two  suppositions 
which  may  be  entertained  regarding  the  mode 
in  which  the  seminal  fluid  gains  the  ovula ; 
for  it  might  either  pass  directly  up  the  tube  of 
the  oviduct,  or  be  absorbed  and  take  some  cir- 
cuitous course. 

In  the  third  place,  we  are  inclined  to  think 
that  in  quadrupeds  the  ova  must  be  already 
fecundated  before  their  arrival  in  the  uterus, 
that  is,  either  in  the  neighbourhood  of  the 
ovary  or  in  the  tubes,  for  this  reason,  that  at 
the  time  when  the  ovum  first  arrives  in  the 
uterus,  it  has  already  become  considerably 
enlarged,  and  has  undergone  some  of  the 
changes  of  development  ;*  and  when  we  con- 
sider how  very  regular  and  progressive  these 
changes  have  been  observed  to  be  from  the 
time  when  the  ovum  first  enters  the  tubes,  we 
shall  be  disposed  to  conclude  that  fecundation 
very  probably  takes  place  before  then,  or  in  the 
upper  part  of  the  tubes. 

In  the  fourth  place,  attempts  have  been 
made  to  trace  the  seminal  fluid  in  animals 
opened  shortly  after  sexual  union.  Most 
authors  agree  that  much  of  the  seminal  fluid 

*  We  do  not  mean  here  to  state  that  the  parts  of 
the  foetus  have  appeared,  but  only  that  changes  in 
the  germinal  membrane  preparatory  to  the  forma- 
tion of  the  foetus  have  taken  place.  Nothing  of 
this  kind  lias  ever  been  found  in  the  unimpregn.ited 
animal,  no  appearance  of  any  ovum,  whicli,  con- 
sidering how  often  vesicles  are  burst  without  sexual 
union,  we  think  must  have  been  the  case  had  the 
ovum  undergone  the  same  changes  in  the  unim- 
pregnated  as  in  the  impregnated  animal  until  its 
arrival  in  the  uterus. 


frequently  flows  out  of  the  vagina  soon  after 
coition,  and  Harvey,  De  Graaf,  and  Haller 
were  all  unable  to  discover  any  traces  of 
seminal  fluid  in  the  uterus  even  of  various 
animals  killed  and  opened  soon  after  sexual 
union.  Haller,  however,  while  he  states  this 
as  the  result  of  his  experiments,  admits  that 
the  means  which  he  possessed  of  ascertaining 
the  presence  or  absence  of  the  semen  were  im- 
perfect, and  he  himself  believed  that  fluid  to 
have  entered  the  uterus. 

Various  other  physiologists,  also,  state  that 
they  have  found  seminal  fluid  in  different 
parts  of  the  female  organs.  Morgagni  and 
Ruysch  had  two  opportunities  of  examining 
the  body  of  the  human  female  very  soon  after 
coition,  and  found,  on  opening  the  uterus,  a 
fluid  which  they  regarded  as  semen.  John 
Hunter  states  that  he  observed  the  same  in  a 
bitch,  as  also  did  Hausmann.  But  in  all 
these  instances  some  doubt  may  be  enter- 
tained regarding  the  fluid  which  was  considered 
as  semen. 

Prevost  and  Dumas,  trusting  to  the  occur- 
rence of  the  seminal  animalculae  as  a  certain 
sign  of  the  presence  of  seminal  fluid,  state 
that  they  have  observed  these  animalcules,  at 
different  periods  after  coition,  both  in  the 
uteius  and  tubes  of  dogs  and  rabbits;  and  it 
appears  to  result  from  the  careful  series  of 
experiments  performed  by  these  physiologists 
that  the  longer  the  time  was  which  had  elapsed 
after  coition,  the  farther  the  seminal  fluid  had 
advanced  upwards  within  the  female  genital 
passages.  Thus,  at  twenty-four  hours  after 
coition  a  great  quantity  of  animalcules  were 
found  in  the  cornua  of  the  uterus,  but  none 
either  in  the  vagina  or  farther  up  the  tubes; 
at  forty-eight  hours  nearly  the  same  was  the 
case  :  on  the  third  and  fourth  days  there  were 
many  animalculse  still  in  the  cornua  and  some 
in  the  tubes,  which  continued  in  the  dog  till 
the  fifth  and  sixth  days;  and  upon  one  occa- 
sion only  they  observed  a  few  animalcules 
near  the  infundibulum. 

Burdach  and  others,  again,  are  not  inclined 
to  place  much  reliance  on  these  observations, 
because  animalcule  of  the  nature  of  Cercariae 
have  been  noticed  in  the  genital  passages  of 
female  animals  which  had  had  no  connection 
with  the  male. 

In  the  fifth  place,  experiments  on  the  me- 
chanical obstruction  of  the  uterus,  Fallopian 
tubes,  and  vagina,  appear  of  considerable  im- 
portance in  reference  to  this  part  of  our  sub- 
ject. Experiments  of  this  kind  were  per- 
formed first  by  Haighton,*  and  afterwards  by 
Blundel^  the  results  of  which,  making  allow- 
ance for  the  more  accurate  knowledge  we  now 
possess  respecting  the  indications  afforded  by 
the  condition  of  the  vesicles  and  corpora  lutea 
in  the  ovary,  may  be  stated  as  follows : — 

1st.  That  when  one  of  the  cornua  of  the 
uterus  or  Fallopian  tube  of  the  rabbit  is  divided 
within  a  few  hours  after  coition,  and  oblite- 
ration of  the  tube  has  followed,  although 
corpora  lutea  are  formed  in  both  the  ovaries 

*  Philos.  Transact,  vol.  Ixxxvi.  p.  173. 


466 


GENERATION. 


(as  a  consequence  of  the  rupture  of  vesicles), 
ova  are  not  to  be  found  on  the  injured  side  of 
the  uterus,  but  pregnancy  takes  place  on  the 
other  side. 

2d.  When  the  vagina  was  divided  in  a  like 
manner  at  its  upper  part,  although  the  usual 
number  of  corpora  lutea  were  found  in  the 
ovaries,  pregnancy  did  not  occur.  That  the  mere 
wound  itself  locally,  or  its  hurtful  effects  on 
the  constitution,  did  not  prevent  the  develop- 
ment of  the  ova,  was  proved  by  the  experiment 
purposely  made  of  dividing  the  parts  in  the 
same  way  and  allowing  them  to  reunite  by 
adhesion  without  obstruction  of  the  tube,  in 
which  case  uterine  pregnancy  occurred  nearly 
as  in  the  natural  condition. 

3d.  In  another  set  of  experiments  oblite- 
ration of  the  tubes  was  caused  to  take  place 
at  a  later  period,  probably  when  the  ova  had 
descended  and  may  be  supposed  to  have  met 
with  the  seminal  fluid,  and  in  these  animals 
pregnancy  occasionally  but  not  always  oc- 
curred. 

It  would  appear  to  follow  from  these  expe- 
riments, that  the  seminal  fluid  does  not  rise  in 
the  female  genital  passages  immediately  upon 
its  introduction,  and  not  for  more  than  a  day 
after  coition,  and  that  those  circumstances 
which  impede  the  rise  of  the  seminal  fluid 
prevent  fecundation.  But  they  do  not  warrant 
the  conclusion  that  impregnation  must  occur 
in  the  ovaries,  since  the  vesicles  may  have  burst, 
their  contents  be  discharged,  and  corpora  lutea 
formed  without  the  seminal  fluid  having  had 
access  to  the  ovary;  a  fact  which  is  well  shewn 
by  the  interesting  experiment  performed  by 
Dr.  Blundell,  of  producing  an  obliteration  of 
the  upper  part  of  the  vagina  in  the  unim- 
pregnated  rabbit,  then  allowing  coition  to  take 
place,  and  then  finding,  no  pregnancy,  but 
corpora  lutea  in  the  burst  vesicles  of  the 
ovary. 

These  experiments  appear  also  as  of  im- 
portance in  shewing  that  neither  absorption  of 
the  semen  by  the  lymphatics  or  bloodvessels, 
nor  the  passage  by  any  other  circuitous  route, 
nor  indeed  any  sympathetic  action  established 
by  sexual  union  between  remote  parts  of  the 
female  generative  organs,  can  be  the  means  of 
producing  fecundation. 

There  are,  no  doubt,  great  difficulties  in  the 
way  of  our  understanding  by  what  manner  the 
seminal  fluid  accomplishes  the  passage  up- 
wards in  the  genital  organs  of  the  female. 
Thus,  the  small  size  of  the  Fallopian  tubes  at 
once  strikes  us  as  a  powerful  obstacle ;  but  in 
many  animals,  as,  for  example,  in  the  Rumi- 
nantia,  there  is  an  equally  great  difficulty  in 
comprehending  how  the  seminal  fluid  gains  the 
uterus  itself  even;  for  in  these  animals  the  os 
uteri  forms  a  long  and  uneven  passage,  inter- 
rupted by  many  hard  cartilaginous  projections, 
and  closed  in  general  by  a  very  viscid  and  tena- 
cious mucus.  But  yet  the  seminal  fluid  must 
in  all  probability  enter  the  cavity  of  the  uterus.* 

*  Burdach  mentions,  as  supporting  the  view  that 
the  seminal  fluid  may  be  absorbed  by  the  blood- 
vessels or  lymphatics,  and  being  carried  into  the 


In  conclusion,  we  would  remark  that  we 
must  either  suppose  fecundation  to  be  the 
effect  of  the  actual  contact  of  the  seminal 
fluid  with  the  ova  in  the  upper  part  of  the 
Fallopian  tube  or  somewhere  near  the  ovary, 
or  we  are  reduced  to  form  the  opinion  that  the 
action  of  the  seminal  fluid  on  the  lower  part 
of  the  female  genital  organs  may  be  twofold, 
viz.  first,  causing  the  commencement  of  the 
process  of  fecundation  by  a  sympathetic  in- 
fluence on  the  upper  part  of  the  tubes,  and, 
in  the  second  place,  perfecting  the  change  in 
the  uterus  when  it  meets  there  with  the  ovum. 
We  feel  inclined,  in  the  present  state  of  our 
knowledge,  to  give  a  preference  to  the  first  of 
these  opinions. 

Nature  of  ike  fecundating  process.  Hypo- 
thesis of  an  aura,  fyc. — We  return  now  to  the 
consideration  of  the  essential  nature  of  the 
change  of  fecundation. 

The  opinion  that  fecundation  is  attributable 
to  the  agency  of  an  aura  or  emanation  from, 
and  not  to  the  material  contact  of  the  seminal 
fluid,  is  founded  chiefly  upon  alleged  instances 
of  conception  having  occurred  in  individuals 
(of  the  human  species)  in  whom,  from  unnatural 
formation  or  disease,  no  direct  passage  existed 
from  the  vagina  or  external  aperture  to  the 
internal  organs,  as  well  as  upon  some  of  the 
circumstances  above  alluded  to,  as  shewing  the 
difficulty  of  such  a  passage  both  in  man  and 
animals,  even  in  the  natural  condition. 

No  very  definite  idea,  it  may  be  remarked, 
can  be  attached  to  the  term  "  aura,"  for  it  has 
been  employed  in  varous  acceptations  by  diffe- 
rent authors ;  one  considering  it  as  of  the 
nature  of  a  gaseous  or  vaporific  exhalation 
from  the  seminal  fluid,  another  denying  it  the 
nature  of  a  substance  even  of  the  most  etherial 
kind,  and  considering  it  more  as  a  spiritual  or 
vital  principle;  and  a  third  regarding  it  as  of 
the  nature  of  a  nervous  impression.  These 
discrepancies  only  shew  us  that  the  term  aura 
is  to  be  taken  rather  as  an  expression  for  the 
unknown  agency  of  the  seminal  fluid  which 
causes  fecundation,  than  as  indicating  its  modus 
operandi  or  the  part  of  its  substance  more 
immediately  concerned  in  the  action.  Some 
authors  have,  however,  even  referred  to  direct 
experiment  in  favour  of  the  agency  of  an  aura. 
Mondat,  for  example,  (De  la  Sterilite,  4to. 
edition,  p.  17)  states  that  he  witnessed  experi- 
ments performed  by  Morsaqui,  of  Turin,  with 
this  view,  from  which  it  was  found  that  the 
bitch  could  be  impregnated  when  it  was  im- 
possible, as  he  states,  that  the  substance  of  the 
seminal  fluid  could  in  substance  pass  into  the 
uterus  or  other  parts.  Recurved  tubes,  con- 
taining in  the  closed  end  a  quantity  of  the 
dog's  seminal  fluid,  were  introduced  into  the 

general  circulation  occasion  fecundation  when  it 
arrives  at  the  ovary  or  other  parts  of  the  internal 
organs,  Casp.  Bartholin,  Perrault,  Sturm,  and 
Grassmeyer.  Dr.  Harlan  of  Philadelphia,  in  a 
volume  of  Experimental  Essays  recently  published, 
states  that  he  found  that  the  injection  of  semen 
into  the  bloodvessels  of  a  bitch  put  a  stop  to  the 
heat  sooner  than  would  otherwise  have  been  the 
case. 


GENERATION. 


467 


vagina  of  the  bitch  in  such  a  way  that  none  of 
the  fluid  itself  could  escape,  but  only  an 
emanation,  vapour,  or  supposed  aura  rising 
from  it,  and  in  eighteen  out  of  thirty  animals 
on  which  the  experiment  was 'performed,  with 
the  subsequent  occurrence  of  impregnation. 
But  until  these  experiments  shall  have  been 
confirmed  by  careful  and  frequent  repetition, 
we  must  be  allowed  to  doubt  the  possibility  of 
performing  such  an  experiment  in  a  sufficiently 
accurate  manner. 

Spallanzani,  with  a  view  to  investigate  the 
powers  of  a  vapour  supposed  to  rise  from  the 
seminal  fluid,  exposed  a  quantity  of  the  ripe 
unimpregnated  spawn  of  the  frog  for  some 
time  in  the  same  vessel  with  a  quantity  of 
seminal  fluid,  the  latter  being  placed  at  the 
bottom  of  the  vessel,  the  ova  at  the  top,  and 
never  was  any  fecundation  produced; — an 
experiment,  it  is  true,  from  which  no  more 
than  negative  evidence  can  be  derived,  but 
upon  the  whole  more  worthy  of  trust  as  being 
subject  to  fewer  fallacies  than  those  of  Mondat. 

The  instances  in  which  it  has  been  alleged 
that  impregnation  has  taken  place  in  the  human 
female  without  there  being  any  possibility  of 
the  seminal  fluid  itself  passing  inwards  in  the 
female  genital  passages,  are  of  a  very  doubtful 
nature,  and  liable  to  so  many  sources  of  fallacy, 
that  we  feel  little  disposed  to  admit  them  as 
grounds  of  proof  of  the  agency  of  an  aura 
seminalis.  In  some  of  the  cases  in  which  it 
has  been  found,  either  in  the  course  of  pregnancy 
or  at  the  time  of  child-birth,  that  the  female 
passages  are  obstructed,  there  is  reason  to  be- 
lieve that  the  closure  has  been  produced  sub- 
sequent to  the  occurrence  of  conception  ;  and 
the  same  may  be  said  of  those  cases  of  ovarian 
gestations  in  which  an  obliteration  of  the  Fal- 
lopian tubes  has  been  observed.  In  the  greater 
number  of  such  cases,  it  may  also  be  observed, 
the  malformation  of  the  parts  has  consisted  in 
the  much  contracted  state  of  the  external  orifice 
or  some  other  part  of  the  passage,  rather  than 
in  their  absolute  closure,  so  that  there  was 
merely  a  difficulty  and  not  an  impossibility  of 
the  entrance  of  seminal  fluid.  But  in  opposi- 
tion to  such  vague  and  ill-ascertained  observa- 
tions, a  variety  of  circumstances,  which  it  is 
not  necessary  to  particularize,  might  be  adduced, 
tending  to  show  how  very  easily  in  the  human 
female  as  well  as  in  other  animals  all  mecha- 
nical obstructions  to  the  entrance  of  the  seminal 
fluid  into  the  uterus  tend  to  prevent  conception. 

General  conclusions  respecting  fecundation. 
In  conclusion  we  would  remark,  1st,  that 
while  we  readily  admit  a  very  small  quantity 
indeed  of  the  seminal  fluid  to  be  sufficient  to 
produce  fecundation,  we  think  that  what  has 
previously  been  stated  warrants  the  conclusion, 
that  material  contact  of  a  certain  quantity, 
however  small,  of  the  seminal  fluid  with  the 
ovum  is  necessary  to  give  rise  to  its  fecunda- 
tion, and,  consequently,  that  the  hypothesis 
of  an  aura  is  untenable.  And  for  the  same 
reasons  it  follows  that  there  are  no  just  grounds 
for  holding  the  opinion  either  that  fecundation 
consists  in  a  sympathetic  action  of  a  nervous 
kind,  or  that  it  is  brought  about  by  the  absorp- 


tion of  the  semen  into  the  circulatory  or 
lymphatic  vessels  of  the  generative  system. 

2d.  It  is  sufficiently  obvious  that  in  quadru- 
peds there  is  no  exact  proportion  between  the 
quantity  of  seminal  substance  or  fluid  received 
by  the  female  or  emitted  by  the  male,  and  its 
effect  in  producing  fecundation, — a  circum- 
stance which  points  out  a  distinction  which 
ought  always  to  be  borne  in  mind  between  that 
vital  change  on  the  female  genital  system  and 
the  whole  economy  and  ovum,  and  the  simple 
physical  re-action  which  may  take  place  be- 
tween the  semen  and  ovum  themselves. 

3d.  We  may  regard  venereal  excitement  of 
the  genital  organs  and  impregnation  of  an 
ovum  as  different  phenomena,  for  though  they 
usually  occur  together,  there  are  instances  in 
which  they  take  place  quite  independently. 

4th.  The  action  of  impregnation  is  to  be 
regarded  as  sui  generis,  or  quite  peculiar  among 
the  vital  processes.  It  is  not  capable  of  being 
imitated  by  any  other  substance  than  the 
seminal  fluid,  and  neither  experiment  nor  ob- 
servation enables  us  to  form  the  most  distant 
conjecture  what  the  nature  of  that  action  may 
be,  which,  from  the  influence  of  the  male  pro- 
duct, confers  upon  the  ovum  a  new  and 
independent  life,  and  enables  to  give  birth  to 
a  new  individual  the  mass  of  organic  matter  in 
the  egg,  which,  without  the  change  of  fecun- 
dation, would  prove  altogether  barren  and 
undergo  no  other  changes  than  those  of  similar 
dead  matters.  The  action,  however,  is  in  some 
respects  reciprocal,  and  we  cannot  determine 
what  part  either  of  the  two  agents  concerned 
performs  in  the  change  of  fecundation :  we 
know  only  this,  that  unless  the  seminal  fluid 
be  of  the  suitable  composition  it  is  ineffectual, 
and  that  ova  are  susceptible  of  its  influence 
only  when  in  that  period  of  their  evolution 
when  they  are  ripe.  Nor  can  we  with  certainty 
fix  on  what  part  of  the  egg  the  influence  of  the 
male  semen  more  immediately  operates.  Since 
the  foetus  grows  from  the  centre  of  the  germinal 
layer,  it  has  been  commonly  supposed  that 
this  is  the  part  of  the  egg  which  is  most  imme- 
diately affected  by  fecundation,  but  we  know 
nothing  of  this;  and  it  might  be  held,  on  the 
other  hand,  that  the  effect  of  fecundation  ope- 
rates on  the  rest  of  the  contents  of  the  egg 
in  enabling  them  to  be  assimilated  round  the 
germinal  centre  or  rallying  point  of  the  de- 
velopment of  the  new  being. 

5th.  It  has  not  yet  been  shewn  that  one 
part  of  the  seminal  fluid  is  more  necessary  to 
impregnation  than  another.  The  seminal 
animalcules  form  a  natural  ingredient  of  the 
fluid  secreted  in  the  testicle  at  the  time  when 
it  is  excreted  for  the  purposes  of  propagation  ; 
they  appear  to  be  invariably  present,  but  addi- 
tional experiments  are  still  wanting  to  prove 
them  to  be  the  active  or  essential  agents  of 
fecundation,  much  more  the  rudiments  of  the 
new  being  within  the  ovum. 

6th.  Like  others  of  the  operations  of  the 
animal  economy,  the  action  of  fecundation  is 
known  principally  in  its  effects;  but  it  seems 
to  be  a  question  worthy  of  investigation  whe- 
ther, in  the  phenomena  exhibited  during  fecun- 


468 


GENERATION. 


elation,  or  the  laws  by  which  this  change  is 
regulated,  it  be  in  any  respect  analogous  in  its 
nature  to  the  operation  of  certain  poisonous  or 
contagious  principles,  as  for  example,  the 
venereal  virus,  vaccine  matter,  the  contagious 
principle  of  small-pox,  measles,  scarlatina, 
plague,  fevers,  &c.  The  inimitable  Harvey 
thus  expresses  himself  regarding  the  essential 
nature  of  fecundation  in  different  parts  of  the 
forty-ninth  Exercitation  on  the  efficient  cause 
of  the  chicken.  "  Although  it  be  a  known 
thing  subscribed  by  all  that  the  foetus  assumes 
its  original  and  birth  from  the  male  and  female, 
and  consequently  that  the  egge  is  produced 
by  the  cock  and  henne,  and  the  chicken  out  of 
the  egge,  yet  neither  the  schools  of  Physicians 
nor  Aristotle's  discerning  brain  have  disclosed 
the  manner  how  the  cock  and  its  seed  doth 
mint  and  coine  the  chicken  out  of  the  egge." 
"  This,"  he  says, "  is  agreed  upon  by  universal 
consent;  that  all  animals  whatsoever,  which 
arise  from  male  and  female,  are  generated  by 
the  coition  of  both  sexes,  and  so  begotten  as  it 
were  per  contagium  aliquod,  by  a  kind  of  con- 
tagion." "  Even  also,"  he  says,  "  by  a  breath 
or  miasma,"  referring  to  the  fecundation  of  the 
ova  of  fishes  out  of  the  body. 

"  The  lac  maris,  male's  milk,  propagating  or 
genital  liquor,  vitale  virus,  vital  or  quickening 
venom,"  are  all  names  of  the  seminal  fluid  of 
the  male.  Again,  "  The  efficient  in  an  egge, 
by  a  plastical  vertue  (because  the  male  did 
only  touch,  though  he  be  now  far  from  touching 
and  have  no  extremity  reached  out  to  it)  doth 
frame  and  set  up  a  foetus  in  its  own  species 
and  resemblance."  "  What  is  there  in  genera- 
tion, that  by  a  momentary  touch  (nay  not 
touching  at  all,  unlesse  through  the  sides  of 
many  mediums)  can  orderly  constitute  the  parts 
of  the  chicken  by  an  epigenesis,  and  produce 
an  univocal  creature  and  its  own  like?  and  for 
no  other  reason  but  because  it  touched  here- 
tofore." 

"  The  qualities  of  both  parents  are  observable 
in  the  offspring,  or  the  paternal  and  maternal 
handy-work  may  be  tracked  and  pointed  out 
both  in  the  body  and  soul."  The  first  cause 
must  therefore  be  of  a  mixed  kind.  "  It  is 
required  of  the  primary  efficient  in  the  fabrick 
of  the  chicken,  that  he  employ  skill,  providence, 
wisdom,  goodness,  and  understanding  far  above 
the  capacity  of  our  rational  souls." 

7th.  In  respect  to  the  part  of  the  female 
generative  system  at  which  fecundation  takes 
place,  it  appears  most  probable  that  in  quadru- 
peds and  the  human  species  this  change  occurs 
before  the  ovum  reaches  the  uterus,  or  some 
way  in  the  course  of  the  Fallopian  tubes ; 
perhaps  most  frequently  in  the  upper  part  of 
them.  There  is,  however,  probably  some 
variation  among  animals  and  in  different  cir- 
cumstances regarding  this  point.  But  while 
we  state  this  as  the  conclusion  most  consistent 
with  facts  in  the  present  state  of  our  know- 
ledge, we  ought  not  to  omit  the  mention  of  the 
more  prominent  facts  by  which  it  is  opposed. 

In  some  of  the  lower  animals,  fecundation 
seems  to  extend  beyond  the  sphere  of  the  ova 
which  are  ripe.    In  the  Aphis  (as  was  already 


mentioned  at  an  early  part  of  the  paper)  the 
production  of  young  by  the  female  goes  on 
for  several  generations  (eleven)  without  any 
sexual  intercourse  after  that  which  gave  rise  to 
the  first.  In  the  Daphnia  Longispina  this  is 
said  also  to  be  the  case  for  twelve  generations, 
and  in  the  Monoculus  pulex  for  fifteen.  The 
queen-bee  lays  fruitful  eggs  during  the  whole 
year  after  being  once  impregnated ;  and  in  the 
instance  of  the  common  fowl  and  some  other 
birds,  previously  referred  to  more  than  once, 
if  we  reject  the  supposition  of  the  seminal 
fluid  remaining  in  action,  it  seems  necessary  to 
suppose  that  fecundation  must  occur  in  the 
ovary,  since  unripe  ova  are  acted  on  by  the 
fecundating  medium  at  the  same  time  with 
those  which  are  arrived  at  maturity  and  are 
ready  to  descend  into  the  oviduct.* 

Many  physiologists  also  believe  that  the 
influence  of  the  first  impregnation  extends  to 
the  products  of  subsequent  ones.  Thus  Haller 
remarks  that  a  mare  which  has  bred  with  an 
ass  and  has  had  a  mule  foal,  when  it  breeds 
next  time  with  a  horse,  bears  a  foal  having 
still  some  analogy  with  the  ass.  So  also  in 
the  often  cited  instance  of  the  mare  which  bred 
with  a  male  Quagga,  not  only  the  immediate 
product,  but  three  foals  in  subsequent  breedings 
with  an  Arabian  stallion,  and  these  three  even 
more  than  the  first,  partook  of  the  peculiarities 
of  the  Quagga  species. 

Instances  of  the  same  kind  are  mentioned 
by  Burdach  as  occurring  in  the  sow  and  bitch; 
and  it  is  affirmed  that  the  human  female 
also,  when  twice  married,  bears  occasionally  to 
the  second  husband  children  resembling  the 
first,  both  in  bodily  structure  and  mental 
powers. 

According  to  Hausmann,  when  a  bitch  has 
connexion  with  several  dogs  (and  this  is  gene- 
rally the  case  during  the  continuance  of  the 
heat,  sometimes  to  the  amount  of  twenty,)  she 
usually  bears  two  kinds  of  puppies  at  least,  and 
the  greater  number  of  these  resemble  the  dog 
with  which  she  first  had  connexion. 

We  feel  at  a  loss  to  decide  what  weight 
ought  to  be  attached  to  these  observations ; 
they  appear  to  bear  chiefly  on  the  subjects 
which  are  discussed  in  the  next  part  of  this 
article. 

V.   MISCELLANEOUS  TOPICS  RELATING  TO  THE 
PRECEDING   HISTORY  OF  GENERATION. 

We  have  deferred  until  now  the  consideration 
of  some  topics  which  usually  find  a  place  in 
the  history  of  the  generative  function,  as  we 
have  thought  it  desirable  to  separate  them  from 
the  preceding  narrative  on  account  of  the 
vagueness  of  the  facts  and  speculative  nature 
of  the  opinions  with  which  they  are  connected. 
The  subject  last  discussed  naturally  leads  to 

*  Burdach  hazards  the  opinion  that  in  some 
quadrupeds  the  ova  may  not  even  be  developed  at 
the  time  of  impregnation,  as  in  the  Roe-deer,  which 
pair  in  July  and  August,  but  do  not  bear  their 
young  till  May,  and  the  Fox,  the  period  of  gesta- 
tion in  which  is  much  longer  than  we  should  sup- 
pose it  ought  to  be,  judging  from  the  analogy  of 
others  of  the  Dog  genus. 


GENERATION. 


469 


the  first  of  these  topics  which  we  shall  con- 
sider, viz. 

§  1.  Superfatution. — In  the  first  section  of 
Part  IV.  it  has  been  mentioned  that  in  the 
human  female,  as  soon  as  the  ovum  has  arrived 
in  the  uterus,  and  even  a  short  while  before 
that  period,  the  passage  through  the  mouth 
and  neck  of  the  uterus  is  closed  by  a  viscid 
mucus,  which  opposes  a  firm  barrier  against  the 
entrance  of  seminal  fluid,  and  thus  prevents 
the  occurrence  of  subsequent  or  reiterated  con- 
ception. In  some  of  the  lower  animals,  on 
the  other  hand,  it  would  appear  that  several 
consecutive  conceptions  not  unfrequently  occur, 
and  in  some  animals  this  may  be  considered  as 
the  natural  mode  of  generation. 

It  becomes  a  point  of  some  interest  both  in 
a  physiological  and  in  a  medico-legal  view  to 
determine,  whether,  as  has  been  supposed  by 
some,  the  same  ever  takes  place  in  the  human 
species. 

The  quadrupeds  in  which  superfoetation 
(as  a  second  conception  during  pregnancy  is 
called)  is  said  to  occur  possess  a  uterus  with 
two  horns,  and  it  may  be  that  in  them  the 
product  of  the  first  conception  has  occupied 
only  one  of  the  cornua  of  the  uterus,  and  that 
the  second  conception  occurred  upon  the  other 
or  empty  side.  This  may  be  the  case  in  the 
hare,  for  example,  which  is  said  to  be  particu- 
larly liable  to  superfoetation.  In  woman  also, 
it  has  been  supposed  that  a  double  form  of 
uterus,  which  is  present  in  rare  instances  as  a 
malformation  of  that  organ,  may  admit  of  a 
second  conception  on  one  side  in  the  course 
of  uterogestation  confined  to  the  other.  But 
though  this  may  be  regarded  as  possible,  we 
are  not  aware  that  any  example  of  the  actual 
occurrence  of  pregnancy  in  both  cornua  of 
a  double  uterus  affords  a  satisfactory  proof 
of  it. 

Great  caution  is  necessary  in  admitting  the 
evidence  of  superfoetation,  as  many  circum- 
stances concur  to  render  it  very  fallacious. 
Women  occasionally  bear  twins,  or  two  chil- 
dren differing  greatly  in  size  and  apparent  age; 
and  many  are  apt  at  once  to  form  the  conclu- 
sion from  thence  that  the  two  children  must 
have  commenced  their  existence  or  have  been 
generated  at  different  times ;  but  it  is  much 
more  likely  in  most  of  these  instances,  that 
the  different  appearance  in  the  size  and  con- 
formation of  the  children  has  arisen  solely 
from  a  difference  in  the  rapidity  and  vigour 
of  their  growth.  In  by  far  the  greater  num- 
ber of  such  instances,  the  smaller  of  the 
children  bears  obvious  marks  of  being  stunted 
in  its  growth,  and  it  is  often  deformed,  blighted, 
or  dead  and  shrunk ;  and  even  although  this 
were  not  the  case  and  the  children  were  both 
alive,  a  mere  difference  of  size  of  children 
born  at  the  same  time  must  be  regarded  as 
very  slight  evidence  indeed  of  so  great  a  devi- 
ation from  the  usual  phenomena  of  pregnancy 
as  superfoetation. 

Those  who  believe  in  the  possibility  of  the 
occurrence  of  superfoetation  found  their  belief 
chiefly  upon  some  rare  instances  of  the  birth 
of  more  than  one  perfectly  developed  child  at 


successive  periods  so  remote  from  one  another 
that  both  cannot  have  been  conceived  at  the 
same  time,  and  it  must  be  admitted  that  these 
cases,  if  correct,  go  far  to  prove  the  possibility 
of  superfoetation. 

In  reviewing  the  cases  of  alleged  super- 
foetation two  questions  at  once  present  them- 
selves for  consideration,  viz.  1st,  whether  a 
second  conception  may  take  place  within  a  few 
hours  or  days  after  the  first,  or  we  may  say  at 
any  period  before  the  ovum  is  settled  in  the 
uterus;  and,  second,  whether  this  may  occur 
at  a  later  period,  as  at  two,  three,  four,  or  more 
months  after  the  first  conception. 

The  puppies  of  a  bitch,  we  have  already 
mentioned,  generally  bear  a  resemblance  to 
more  than  one  of  the  dogs  with  which  she  has 
had  connexion  during  the  period  of  heat,  and 
this  period  may  extend  to  eight  or  nine  days. 
A  mare,  which  had  been  covered  by  a  stallion, 
was  five  days  afterwards  covered  by  an  ass, 
and  bore  at  the  usual  time  twins,  one  of  which 
was  a  common  foal,  the  other  a  mule.* 

Women  have  been  known  to  bear  two  chil- 
dren of  different  colour;  and  in  one  of  these 
instances  the  mother  is  said  to  have  confessed 
to  having  admitted  the  embraces  of  a  black 
servant  a  few  hours  after  her  husband,  who  was 
white. 

Facts  like  these  seem  to  shew  that  sexual 
intercourse  limited  to  an  interval  of  a  few  days 
(most  probably  before  the  uterus  has  been 
closed  by  the  decidua)  may  produce  super- 
foetation. But  we  would  remark  that,  although 
it  may  be  that  the  mechanical  obstruction  of 
the  decidua  opposes  an  obstacle  to  the  passage 
of  semen  upwards,  or  the  descent  of  a  new 
ovum  into  the  uterus,  there  is  obviously  ano- 
ther cause  why  superfoetation  should  not  occur : 
we  mean  that  fundamental  change  in  the  con- 
stitution which  is  induced  by  pregnancy, 
similar  to  that  which  continues  in  the  majority 
of  women  during  lactation.  But  for  such  a 
constitutional  change,  we  conceive  continual 
derangement  of  the  function  of  utero-gestation 
would  attend  that  process  in  consequence  of 
the  recurrence  of  some  of  the  more  general 
symptoms  of  conception,  even  although  a 
lodgement  of  a  new  ovum  in  the  cavity  of  the 
uterus  were  impossible. 

The  following  cases  serve  to  illustrate  the 
nature  of  the  more  important  facts  on  record 
which  do  not  admit  of  an  explanation,  except- 
ing on  the  supposition  that  superfoetation  has 
taken  place. 

1 .  A  woman  bearing  a  full-grown  male  child 
had  neither  lochia  nor  milk  after  its  birth,  and 
a  hundred  and  thirty-nine  days  afterwards 
bore  a  second  child — a  living  girl,  when  the 
milk  and  lochia  came  naturally.  Eisenmann, 
who  had  observed  this  case,  explained  the 
occurrence  by  supposing  that  a  double  uterus 
existed;  but  upon  the  woman's  death  some 
time  afterwards,  no  unusual  structure  -was 
found.f 

*  Archiv.  Gen.  torn.  xii.  p.  125.  Another 
similar  instance  is  related  in  torn.  xvii.  p.  89,  of  the 
same  work. 

t  See  Burdach's  Physiol. 


470 


GENERATION. 


2.  Desgvanges  observed  another  instance  in 
which  a  woman  bore  two  girls  at  the  interval 
of  a  hundred  and  sixty-eight  days  in  the 
same  circumstances  as  in  the  above-mentioned 
case.* 

3.  A  third  case  is  related  by  Fournier  in 
which  two  girls  were  born  at  the  interval  of 
five  months,  there  being  lochia  for  a  few  days 
after  the  birth  of  the  first.f 

4.  A  fourth  instance  is  mentioned  of  two 
children  born  at  the  interval  of  a  hundred 
and  nine  days.J 

5.  Velpeau  relates  that  a  Mad.  Bigaux  had 
first  a  living  child,  and  four  and  a  half  months, 
or  a  hundred  and  forty  days  afterwards,  a 
second,  also  alive.§ 

We  confess  that  we  think  these  cases,  if 
correctly  reported,  go  far  to  prove  the  possible 
occasional  occurrence  of  supeifcetation  in  the 
human  species.  On  the  supposition  that  two 
children  born  alive  at  different  periods  remote 
from  one  another  have  been  conceived  at  the 
same  time,  three  months  appears  to  be  the 
greatest  extent  to  which  the  interval  between 
their  births  could  reach,  the  first  being  born 
prematurely  at  six  and  a  half  or  seven  months, 
and  the  second  being  retained  in  the  uterus 
till  the  period  of  nine  and  a  half  or  ten  months; 
but  this  is  improbable  in  some  of  the  instances 
before  us,  as  both  children  appeared  equally 
complete,  and  no  mere  difference  in  the  rate 
of  their  growth  could  account  for  their  birth  at 
so  remote  periods. 

We  are  reduced  then  to  the  necessity  of  ad- 
mitting the  possibility,  in  very  rare  instances,  of 
superfoetation  ;  but  at  the  same  time  we  may 
remark  that  the  evidence  regarding  it  is  not 
sufficiently  precise,  and  we  are  left  entirely  at 
a  loss  to  explain  what  causes  may  give  rise  to 
this  variation,  and  in  what  manner  the  seminal 
fluid  may  be  supposed  to  pass  through  the 
uterus,  or  the  new  ovum  to  gain  an  entrance 
there. 

§  2.  Influence  exerted  by  parents  on  the 
qualities  of  their  offspring  in  generation. — 
One  of  the  most  obvious  and  important  laws 
of  the  reproductive  function  is  that  by  which 
the  specific  distinction  of  animals  is  preserved. 
Like  produces  like ;  and  for  the  most  part  an 
undeviating  succession  of  generations  of  simi- 
lar structure  and  qualities  prevents  both  the 
extinction  of  any  species  and  its  being  blended 
with  or  lost  in  any  other.  Numerous  examples 
will  recur  to  the  mind  of  every  one,  of  striking 
family  resemblance,  which  point  out  in  how 
many  respects  children  frequently  inherit  their 
qualities  from  their  parents ;  but  it  must  be 
held  in  remembrance  that  family  or  hereditary 
resemblance  is  seldom  if  ever  complete,  but 


*  Diet,  des  Scien.  Med.  torn.  liii.  p.  418. 
%  Ibid.  torn.  iv.  p.  181. 

t  Stark's  Archiv  fur  die  Geburtshulfe,  &c.  B.  iv. 
S.  589. 

§  Traite  d'Accouchements,  tom.i.  p.  345,  where 
cases  are  referred  to  by  Pignot  in  the  Bull,  de  !a 
Facult.  4e  Annee,  p.  123,  by  Wendt,  Journal  des 
Progres,  torn.  x.  and  Fahrenhorst,  ibid.  torn.  viii. 
p.  161. 


only  of  that  more  general  kind  which  belongs 
to  the  species.  Thus  in  one  family  we  re- 
cognise numerous,  minute  differences,  and  in 
fact  it  may  be  said  that  there  are  scarcely  any 
two  individuals  of  the  same  or  of  different 
family  exactly  alike.  In  respect  to  sex,  the 
most  obvious  difference  exists :  the  mother 
producing  male  and  female;  the  son  is  not  an 
exact  copy  of  his  father,  nor  the  daughter  of 
her  mother,  nor  are  they  a  mixture  of  both ; 
but  each  of  them  bears  certain  resemblances  to 
one  or  other  or  to  both  of  the  parents,  into 
which  it  may  be  interesting  to  inquire, — an  in- 
vestigation which  is  to  be  regarded  of  some 
practical  importance  in  reference  to  the  breed- 
ing of  cattle  and  other  stock. 

As  the  female  parent  furnishes  the  greater 
part  of  the  substance  of  the  egg  in  all  animals, 
and  in  viviparous  animals  provides  also  the 
materials  which  serve  for  the  nourishment  of 
the  young  with  which  it  is  intimately  con- 
nected during  utero-gestation,  it  might,  a  priori, 
have  been  supposed  that  the  offspring  should 
be  more  subject  to  be  influenced  by  the  qua- 
lities of  the  mother  than  by  those  of  the  father; 
but  no  general  fact  of  this  kind  is  established, 
and  instances  need  not  here  be  adduced  which 
shew  that  the  offspring,  whether  male  or  fe- 
male, bears  nearly,  if  not  quite,  as  many 
points  of  resemblance  to  the  father  as  to  the 
mother. 

Such  influence  as  the  male  parent  exerts 
upon  the  qualities  of  the  offspring  must  be 
transmitted  and  take  effect  at  the  period  of 
conception  only,  and  the  impression  being 
that  of  the  contact  of  the  seminal  fluid  with 
the  ovum  must  be  momentary  only.  A  cer- 
tain part  of  the  female  parent's  influence  is 
dependent  on  the  original  constitution  of  the 
ovum  formed  in  her  body,  while  another  part 
of  that  influence  may  be  supposed  to  extend 
through  the  whole  period  of  utero-gestation. 

We  shall  first  consider  those  instances  of 
the  transmission  of  hereditary  qualities  which 
appear  to  belong  to  the  original  constitution 
of  the  male  and  female  generative  products, 
and  subsequently  make  some  remarks  on  the 
influence  which  the  female  has  been  held  to 
exert  during  the  whole  of  pregnancy. 

The  general  structure  of  the  body,  the  sta- 
ture, form,  size  of  the  bones,  disposition  to 
the  formation  of  muscle,  deposition  of  fat,  or 
the  reverse,  seem  to  depend  as  frequently  on 
the  female  as  on  the  male  parent  in  the  human 
species.  In  some  animals  the  male  parent 
more  frequently  determines  the  size  and  general 
form  of  the  body,  as  among  feline  animals, 
dogs,  horses,  &c.  The  bantam  cock  is  said  to 
cause  the  common  hen  to  lay  a  small  egg,  and 
the  common  cock  causes  the  bantam  hen  to 
lay  a  larger  egg  than  usual. 

An  enumeration  of  all  the  points  of  struc- 
ture which  constitute  family  resemblance  would 
detain  us  too  long,  and  is  unnecessary  as  they 
are  familiar  to  every  one.  It  does  not  appear 
to  be  satisfactorily  established  that  the  family 
resemblance  is  derived  more  from  one  than 
from  the  other  parent,  though  in  one  family 
the  influence  of  the  one  parent,  and  in  another 


GENERATION. 


471 


family  the  influence  of  the  other  parent,  may 
predominate.* 

Nor  does  it  appear  that  any  general  law  has 
been  established  regarding  the  transmission  of 
the  nature  of  the  constitution,  temperament, 
state  of  health,  duration  of  life,  &c;  for  in  the 
human  species  at  least  these  qualities  of  the 
offspring  seem  to  be  inherited  from  either 
parent  or  from  both  indiscriminately. 

The  complexion  and  colour  of  the  offspring 
has  received  much  attention.  In  some  animals 
the  colour  of  both  parents  is  sometimes  pre- 
served, as  in  the  piebald  horse ;  in  others  a 
mixture  of  the  colours  of  the  father  and  mo- 
ther appears  in  the  offspring  as  an  interme- 
diate tint.  In  other  animals,  and  most  fre- 
quently in  the  human  species,  the  colour  de- 
scends from  one  only  of  the  parents.  Thus 
among  white  races  of  the  human  species,  it 
happens  more  frequently,  when  the  parents  are 
of  different  complexion,  that  the  child  takes 
after  one  or  other  of  them  than  that  its  com- 
plexion is  intermediate  between  those  of  the 
parents ;  but  it  does  not  appear  as  yet  to  be 
ascertained  that  one  parent  determines  the 
colour  more  frequently  than  the  other.  The 
offspring  from  the  union  of  people  of  dark 
and  white  races  of  the  human  species  usually 
has  a  complexion  which  is  a  mixture  of  or  is 
intermediate  between  the  complexions  of  the 
two  parents,  as  in  the  Mulatto  and  other  degrees 
of  colouring;  but  it  is  alleged  that  in  these 
instances  the  colour  of  the  father  usually  pre- 
dominates over  that  of  the  mother.  Thus  a 
dark  father  produces  with  a  white  mother  a 
darker  child  than  a  white  father  with  a  dark 
mother.  Among  animals  there  are  infinite 
varieties  in  this  respect.  White  colour  is 
said  to  be  more  readily  transmitted  than  others. 
In  some  animals,  however,  colour  is  trans- 
mitted with  great  regularity  :  thus  it  has  been 
found  that  as  many  as  two  hundred  and  five 
of  the  product  of  two  hundred  and  sixteen 
pairs  of  horses  of  similar  colour  inherited  the 
colours  of  their  parents. 

The  degree  of  fruitfulness  in  bearing  off- 
spring, or  the  opposite,  sterility,  the  qualities  of 
the  voice,  peculiarities  in  the  degree  of  deli- 
cacy of  the  external  senses,  as  long  or  short- 
sightedness, musical  ear,  &c,  the  physical 
powers  of  the  body  as  illustrated  in  the  speed 
or  strength  of  horses,  and  peculiarities  of  the 
digestive  functions  of  the  nature  of  idiosyn- 
crasies, are  other  familiar  examples  of  bodily 
qualities  usually  transmitted  in  hereditary  de- 
scent from  one  or  other  parent  to  the  offspring. 

Lastly,  the  qualities  of  the  mind  are,  perhaps 
as  much  as  the  bodily  configuration  and  powers, 
subject  to  influence  from  the  hereditary  in- 
fluence of  parents  upon  their  offspring.  The 
powers  of  observation,  memory,  judgment, 
imagination,  the  fancy,  and  all  that  belongs  to 
what  is  usually  called  genius,  the  emotions, 

*  Br.  Walker,  in  a  short  essay  lately  printed  for 
private  distribution,  has  attempted  to  shew  that  the 
upper  and  back  part  of  the  head  usually  resembles 
the  mother,  the  face  from  the  eyes  downwards 
most  frequently  the  father. 


passions,  desires,  and  appetites,  as  inborn 
mental  qualities  of  the  offspring,  are  all  liable 
to  be  influenced  in  the  act  of  generation  by 
the  parents.* 

The  hereditary  predisposition  of  man  and  ani- 
mals to  particular  diseases  also  illustrates  in  a 
striking  manner  the  general  law  now  under  con- 
sideration, and  from  its  importance  in  reference 
to  life  assurance  has  attracted  considerable  at- 
tention. 

Almost  all  the  forms  of  mental  derangement 
are  more  or  less  directly  hereditary,  one  of  the 
parents  or  some  near  relation  being  affected. 
Of  bodily  diseases,  pulmonary  complaints, 
diseases  of  the  heart,  scrofula,  rickets,  worms, 
gout,  rheumatism,  hemorrhoids,  hypochondri- 
asis, scirrhus,  apoplexy,  cataract,  amaurosis, 
hernia,  urinary  calculi,  may  be  mentioned  as 
examples  of  diseases  more  or  less  directly 
transmitted  as  predispositions  from  parent  to 
offspring.  The  goitral  and  cretinous  affections 
combined  with  deficient  intellect  are  striking 
examples  of  the  effect  of  hereditary  influence 
combined  with  that  of  the  situation  in  which 
the  cretins  live.  The  union  of  goitrous  per- 
sons in  particular  districts  leads  to  the  pro- 
duction of  cretins,  while  the  union  of  a  cretin 
with  a  healthy  person  tends  to  the  improve- 
ment of  the  offspring,  or  its  gradual  return  to 
the  healthy  state. 

The  predisposition  to  disease  may  be  trans- 
mitted to  the  offspring  from  either  parent,  and 
from  the  one  as  often  as  from  the  other,  but 
much  more  certainly  when  both  the  parents 
have  been  affected  with  the  disease. 

We  may  also  fhention,  in  connection  with 
this  subject,  the  transmission  to  the  offspring 
of  various  marks  and  deformities  in  the  struc- 
ture of  the  parents  or  their  relations.  The 
cretinism  already  mentioned  is  one  of  these, 
and  there  are  numerous  other  cerebral  de- 
formities which  are  so  transmitted,  as  congeni- 
tal malformations,  such  as  the  acephalous  and 
anencephalous  states,  spina  bifida,  cyclopia,  &c. 
which  run  remarkably  in  particular  families. 
In  many  instances  the  hereditary  cause  of 
these  deformities  has  been  distinctly  traced  to 
one  or  other  of  the  parents.  Naevus,  moles, 
growths  of  hair  in  unusual  places,  hare-lip, 
deficient  or  supernumerary  toes  or  fingers, 
have  all  been  traced  to  hereditary  influence, 
and  probably  as  often  to  the  one  parent  or  his 
family  as  to  the  other.  Malformations  of  the 
heart,  congenital  hernia,  and  indeed  most  other 
malformations,  are  capable  of  being  traced  to  a 
similar  origin. 

Were  further  illustration  of  this  general  law 
requisite,  it  would  be  found  in  the  resem- 
blance of  mules  or  hybrids  produced  by  the 
union  of  two  distinct  races,  varieties,  or 
species  of  animals,  which  productions  also 
afford  an  excellent  opportunity  of  observing 

*  In  endeavouring  to  estimate  the  degree  of 
original  resemblance  of  offspring  to  parent  mentally 
as  well  as  bodily,  but  especially  the  former,  great 
caution  is  necessary  not  to  overlook  that  resem- 
blance between  them  which  depends  on  education, 
similar  habits,  pursuits,  mode  of  life,  and  conti- 
nual intercourse. 


472 


GENERATION. 


and  comparing  the  amount  of  hereditary  in- 
fluence exerted  by  one  or  other  of  the  parents. 
The  hybrid  usually  combines  to  a  certain  ex- 
tent the  qualities  of  its  father  and  mother,  as 
in  the  familiar  example  of  the  common  mule 
between  the  male  ass  and  the  mare,  or  in  the 
product  of  the  tiger  and  the  lion,  the  dog  and 
wolf,  the  pheasant  and  black  grouse,  the  gold 
and  common  pheasant,  and  others.  In  some 
mules  the  qualities  of  the  father  predominate, 
in  others  those  of  the  mother ;  but  so  far  as 
we  are  aware,  the  isolated  facts  regarding  this 
point  have  not  yet  been  brought  under  any 
general  law. 

It  has  been  asserted  that  acquired  qualities, 
whether  mental  or  bodily,  of  the  parents  are 
capable  of  being  transmitted  to  their  offspring. 
Thus  the  superiority  of  a  civilized  over  a  bar- 
barous nation  is  said  to  depend,  not  solely  on 
the  influence  of  an  advanced  state  of  educa- 
tion upon  each  new  comer,  but  also  on  the 
greater  natural  powers  of  the  children,  derived 
from  their  parents  at  the  moment  of  their 
production,  or,  in  other  words,  the  greater 
capability  of  the  children  to  receive  the  higher 
mental  acquirements  and  more  refined  ideas 
belonging  to  the  civilized  condition  of  society. 

Farther,  it  is  asserted  that  dogs  and  cats 
which  have  accidentally  lost  their  tails  have 
brought  forth  young  ones  with  a  similar  de- 
formity. Blumenbach  affirms  that  a  man  who 
had  lost  his  little  finger  had  children  with  the 
same  defect.  A  wound  of  the  iris  and  a  defor- 
mity of  the  finger  occasioned  by  whitlow  are 
said  to  have  been  transmitted.  The  well-trained 
pointer  of  this  country  produces  a  puppy 
much  more  capable  of  being  trained  than  the 
dogs  of  the  original  breed.  The  retriever  spaniel 
and  the  shepherd's  colly  are  said  to  do  the 
same.  Well-broken  horses  produce  docile 
foals,  and  lastly,  the  young  of  foxes  living  in 
hunting  countries  are  naturally  much  more 
circumspect  than  those  living  in  countries 
where  they  are  not  exposed  to  the  danger  of 
pursuit. 

We  look  upon  all  these  alleged  facts  with 
distrust.  Many  of  them  are  coincidences; 
others,  we  suspect,  are  false.  It  is  obviously 
insufficient  for  our  purpose  to  ascertain  the 
qualities  of  the  one  generation  which  is  born. 
We  must  also  know  to  what  circumstances 
the  parent  may  have  owed  its  peculiarity.  We 
feel  convinced  that  education  more  than  any 
other  circumstance  has  influenced  the  superior 
powers  of  the  animals  above  alluded  to,  and 
there  is  no  proof  that  the  parent  did  not 
possess  the  same  capabilities  or  natural  powers 
as  the  offspring. 

There  are,  on  the  other  hand,  innumerable 
instances  which  shew  that  acquired  alterations 
of  structure  are  not  transmitted.  How  many 
men  are  there  who  have  lost  limbs  and  yet 
have  produced  children  in  no  respect  maimed. 
A  quadruped  without  the  fore-legs  has  borne 
entire  young.  A  bitch  in  which  the  spleen 
had  been  extirpated  had  young  possessing  that 
organ.  Men  with  only  one  testicle  have  sons 
with  the  usual  number ;  and  lastly,  the  people 
of  nations,  the  males  of  which  have  been  cir- 


cumcised during  hundreds  of  years,  have  chil- 
dren with  foreskins  not  a  bit  shorter  than  those 
of  nations  in  which  no  such  practice  exists. 

The  breeding  of  domestic  animals  of  dif- 
ferent kinds,  suited  respectively  to  the  various 
useful  purposes  for  which  they  are  employed, 
is  a  subject  connected  with  the  present  question 
of  high  practical  importance ;  but  unfortu- 
nately, though  some  practical  men  have  well 
understood  the  proper  method  to  be  pursued, 
it  is  to  be  regretted  that  the  facts  have  never 
been  reduced  to  general  rules,  and  that  the 
theory  has  been  almost  entirely  neglected. 

It  is  generally  admitted  as  a  fact  proven 
that  in  the  ox,  horse,  and  other  domestic 
animals  the  purer  or  less  mixed  the  breed  is, 
there  is  the  greater  probability  of  its  trans- 
mitting to  the  offspring  the  qualities  which  it 
possesses,  whether  these  be  good  or  bad. 
Economical  purposes  have  made  the  male  in 
general  the  most  important,  simply  because 
he  serves  for  a  considerable  number  of  females. 
The  consequence  of  this  has  been  that  more 
attention  has  been  paid  to  the  blood  or  purity 
of  race  of  the  stallion,  bull,  ram,  and  boar 
than  to  that  of  their  females  ;  and  hence  it  may 
be  the  case  that  these  males  more  frequently 
transmit  their  qualities  to  the  offspring  than  do 
the  inferior  females  with  "which  they  are  often 
made  to  breed.  But  this  circumstance  can 
scarcely  be  adduced  as  a  proof  that  the  male, 
caeteris  paribus,  influences  the  offspring  more 
than  the  female. 

Bad  as  well  as  good  qualities  may  be  trans- 
mitted, and,  therefore,  it  is  obvious  that  in 
endeavouring  to  improve  any  stock  by  engraft- 
ing a  good  quality,  the  breeder  must  choose  a 
male  which,  besides  the  requisite  good  quality, 
is  free  from  those  defects  of  the  female  which 
it  is  desirable  to  sink.  He  must  also  select  a 
male  in  the  family  of  which  the  desired  quality 
has  been  long  resident.  He  cannot  engraft 
the  quality  all  at  once,  but  must  endeavour  to 
introduce  it  by  frequent  crossing. 

In  the  horse,  for  example,  the  strength  of 
bone  and  weight  of  muscle  suitable  for  slow 
draught,  the  light  frame  and  prodigious  swift- 
ness of  the  race-horse,  and  the  intermediate  or 
rather  combined  qualities  of  the  carriage-horse, 
hack,  or  hunter,  are  all  capable  of  being  pro- 
duced by  proper  attention  to  purity  or  mixture 
of  breeds.  The  pace,  speed,  action,  temper, 
courage,  colour  or  quality  of  hair,  and  almost 
all  other  qualities  may  be  increased,  dimi- 
nished, or  altered  by  a  judicious  admixture  of 
different  races.  So  also  the  immense  weight 
of  beef  and  fat  of  the  large  ox,  the  flavour 
of  the  flesh,  the  abundance  or  richness  of  the 
milk  of  the  cow,  are  subject  to  modification  in 
every  different  breeding. 

The  economical  breeder,  then,  while  he  has 
settled  in  his  mind  the  object  which  he  wishes 
to  accomplish  in  any  of  his  stocks,  must  hold 
in  recollection  that  it  is  only  by  the  combi- 
nation and  continued  succession  of  good  qua- 
lities that  he  can  ensure  a  permanent  improve- 
ment. He  must  not  expect  to  be  able  to 
effect  this  by  crossing  the  breed  of  an  impure 
blooded  or  worn-out  female  with  a  male  of 


GENERATION. 


4T3 


superior  qualities.    Bad  qualities  may  become  fear  that  the  mind,  with  all  its  peculiar  tastes, 

as  fixed  as  good  ones,  and  a  judicious  selection  prejudices,  and  passions,  has  too  much  to  do 

of  the  good  ones  (as  adapted  for  his  purpose)  with  the  greater  number  of  matrimonial  al- 

ought  to  be  his  first  and  principal  object.*  liances  to  allow  physiological  considerations 

A  belief  exists  with  some,  founded,  it  is  much  jurisdiction, 
said,  both  on  common  observation  and  scien-  From  the  different  facts  now  touched  upon, 
tific  research,  that  frequent  breeding  in  the  it  is  obvious  that  the  original  type  of  the  parents 
same  family,  or  what  is  commonly  called  modifies  that  of  their  offspring;  while,  in  gene- 
breeding  in  and  in,  has  the  effect  of  deterior-  ral,  varieties  accidentally  acquired  do  not  pass 
ating  a  race.  There  appears,  however,  much  in  hereditary  descent,  unless  they  are  of  such  a 
reason  to  believe  that  the  opinion  just  now  nature  as  to  constitute  a  permanently  distinct 
stated  is  founded  in  error.  In  a  state  of  nature  race  or  variety. 

it  not  unfrequently  happens,  among  those  ani-       In  the  mixture  of  different  races  of  the  human 
mals  especially  which  do  not  pair,  that  the  species  and  of  distinct  species  of  animals  we 
strongest  males  take  precedence  of  the  weaker,  recognise  a  constant  tendency  in  succeeding 
and   naturally  select  the  finest  females   (as  generations  to  return  to  the  original  type  or  pure 
occurs  in  the  deer);  but  in  a  state  of  domes-  breed;  an  effect  which  seems  to  proceed  natu- 
ticily  this  cannot  always  be  the  case,  and  rally  from  the  general  law  already  announced, 
inferior  animals  coming  together  give  rise  to  that  the  purer  the  breed  of  either  of  the  parents, 
inferior  offspring;   but,   if  in  the  farm-yard  or  in  other  words,  the  more  nearly  it  approaches 
sufficient  care  be  taken  in  the  selection  of  the  the  original  type  or  unmixed  race,  the  more 
breeding  males  and  females,  it  does  not  appear  readily  will  its  qualities  descend  to  the  off- 
that  near  relationship  has  any  effect  in  dete-  spring  .    When  the  mixed  offspring  of  the  black 
riorating  the  race,  nor  in  impeding  the  trans-  and  white  races  of  men  unites  with  either  the 
mission  of  good  qualities  which  may  be  found  black  or  the  white,  the  offspring  in  successive 
in  males  and  females  of  the  same  family.  generations  becomes  more  and  more  nearly 
The  belief  now  alluded  to  has  been  held  in  allied  to  the  pure  breed  with  which  the  cross  is 
relation  to  the  human  species  also,  and  it  is  made,  and  at  last  wholly  identified  with  it. 
affirmed  that  both  the  bodily  and  mental  qua-  We  must  look  upon  this  general  law  of  the 
lities  of  the  offspring  suffer  gradual  and  pro-  tendency  of  all  mixed  varieties  to  return  to  the 
gressive  injury  from  the  continued  mixture  of  original  type, together  with  the  circumstance  that 
successive  generations  of  the  same  family  or  a  hybrids  rarely  breed  as  means  adopted  by  na- 
small  number  of  families.     Hence  we  find  ture  for  the  preservation  of  distinct  species, 
that  the  marriage  of  cousins-german,  which       The  transmission  of  hereditary  resemblance, 
is  according  to  law  in  this  country,  is  repro-  either  as  regards  the  general  structure  of  the 
bated  as  prejudicial  by  some;   and  various  body  or  peculiarities,  is  not,  however,  invan- 
royal  families  and  aristocratic  families  are  re-  able,  nor  always  immediate  from  parents  to  off- 
ferred  to  as  examples  of  the  bad  effect  of  spring.    Thus  parents  with  certain  deformities 
the  restriction  of  conjugal  union  to  a  narrow  may  produce  all  their  children  naturally  formed 
circle.  and  healthy ;  or  some  of  them  only  (in  one 
It  must  be  remembered,  however,  that  the  case  the  males,  in  a  second  the  females,  in  a 
mutual  selection  of  the  parents  is  not  quite  the  third  some  of  both  sexes)  may  inherit  the  ab- 
same  in  the  human  species  as  among  the  lower  normal  peculiarity,  while  the  rest  of  the  chil- 
animals  ;  and  in  the  examples  just  referred  to  dren  are  healthy.    But  these  healthy  children, 
we  feel  even  inclined  to  doubt  whether,  when  from  some  disposition  of  their  constitution,  may 
due  allowance  is  made  for  the  nature  of  their  transmit  to  their  descendants  either  in  the  first 
education,   it  will   be  found   that  kings  or  or  in  a  subsequent  generation  the  defect  which 
princes  have  become  worse  or  less  talented  existed  in  their  parents.  The  varieties  in  this  re- 
in modern  than  in  ancient  times,  or  whether  spect  in  the  human  species  are  almost  infinite, 
among  that  class  there  is,  on  an  average,  a  Thus, in  one  family  all  the  children  resembleone 
greater  proportion  of  stupid  men  than  in  other  parent  in  a  striking  manner ;  in  another  the 
ranks  of  society.  male  children  take  after  the  father  chiefly,  the 
The  regularity  of  feature  and  beauty  of  the  females  after  the  mother  ;  and  in  a  third  the 
Persian  race  has  been  greatly  improved  by  converse  holds,  the  peculiarities  of  the  father 
their  choice  of  the  most  beautiful  Circassian    descending  principally  to  daughters,  those  of 
and   Georgian  wives ;   and  there  are  many    the  mother  to  sons,- — an  arrangement  of  family 
examples  of  particular  families  in  this  country    resemblance  which  is  the  most  commonly  pre- 
in  which  regular  and  handsome  features  and  a    valent  according  to  M.  Girou,  who  endeavours 
well-knit  and  fully  developed  form  of  body    to  shew  that  family    resemblance  frequently 
are  hereditary.    We  shall  not  pursue  the  at-    passes  in  an  alternating  manner  from  grand- 
tempt,  however,  which  some  have  made  to    parent  to  grandchild.    Thus,  the  grandchild 
apply  the  principles  of  cattle-breeding  to  the    resembles  the  grandparent  of  the  same  sex,  so 
human   species  ;  for  however  desirable  and    that  a  boy  whose  father  is  like  his  (the  father's) 
necessary  an  improvement  of  the  breed  may     mother  resembles  most  the  grandfather,  as  in 
appear  to  some  Utopian  philanthropists,  we    the  following  plan. 

^st  Generation.  Grand/.  Grandm.  Grand/.  Gramlm. 
2d       ditto  |  Father      Mother  | 

3d       ditto  Son        Daughter       Son  Daiifrh. 

If  it  should  be  proved  that  a  first  or  earlier 

2  I 


*  We  refer  the  reader  to  the  Farmer's  Series  of 
the  Library  of  Useful  Knowledge.    Vols.  Horse 
and  Cattle. 
vol.  ir. 


474 


GENERATION. 


impregnation  influences  the  product  of  a  sub- 
sequent one,  in  breeding  any  particular  stock 
of  animals,  it  would  appear  of  importance  that 
the  female  should  always  breed  with  well  qua- 
lified males;  and  farther,  that  the  genealogy  of 
both  parents  for  one  step,  if  not  more,  back- 
wards, ought  to  enter  as  an  item  into  the  cal- 
culation of  the  probable  qualifications  of  the 
offspring. 

Much  information  is,  however,  still  wanting 
on  this  subject,  which,  as  it  involves  the  most 
obscure  parts  of  the  generative  process,  we  can 
hardly  expect  ever  to  be  able  to  fathom.  It 
cannot  but  be  a  matter  of  wonder  and  extreme 
interest  to  inquire  how,  in  the  unformed  germi- 
nal spot  of  the  egg  of  the  female  at  the  moment 
when  it  receives  the  vital  fecundating  influence 
of  the  male  semen,  the  disposition  to  the  forma- 
tion of  those  minute  modifications  of  structure 
and  function  which  constitute  hereditary  re- 
semblances is  capable  of  being  retained  and 
transmitted  to  the  future  offspring. 

The  celebrated  Darwin  and  some  other  fan- 
ciful speculators  on  physiological  subjects  held 
an  opinion*  that  the  transitory  state  of  the 
minds  of  the  father  or  mother  at  the  instant  of 
conception  has  a  marked  influence  on  the  men- 
tal and   physical  qualities  of  the  offspring. 
Thus  it  has  been  alleged  that  children  begotten 
after  debauchery  or  drunkenness  are  liable  to 
idiocy  or  weakness  both  of  mind  and  body  ; 
that  when  the  amorous  propensities  are  too 
much  excited,  the  offspring  runs  the  risk  of 
erring  in  the  same  way  ;  and  in  short,  that  ac- 
cording to  the  predominance  of  one  or  other 
sentiment,  propensity,  or  frame  of  mind,  the 
offspring  may  be  a  genius  or  a  dolt,  a  sentimen- 
tal swain  or  an  unfeeling  brute,  a  thief,  a  rob- 
ber, a  murderer,  &c.    Leaving  to  others  the 
proof  or  disproof  of  the  alleged  facts  upon  which 
the  above-mentioned  belief  is  founded,  we 
would  take  the  liberty  of  expressing  our  doubts 
as  to  whether  at  the  particular  time  alluded  to 
by  these  theorists  any  idea  but  one  is  usually 
predominant.    Nor  shall  we  here  dwell  upon 
the  obvious  local  treatment  which  is  applicable 
upon  the  phrenological  view  of  the  subject; 
but  as  few  may  be  aware  of  the  real  importance 
of  that  critical  period  in  which  life  is  conferred 
upon  a  new  being,  we  have  thought  it  right  to 
put  our  married  readers  at  least  upon  their 
guard  against  unrestrained  yielding  to  any  of 
the  baser  feelings  or  ideas,  which  do  creep  into 
the  best-regulated  establishments,  requesting  at 
the  same  time  that  they  will  communicate  to 
their  partners  such  information  as  may  be  con- 
sidered necessary  for  the  attainment  of  the  grand 
object  in  view,  viz.  the  improvement  of  the  po- 
pulation of  this  kingdom. 

The  belief  now  stated  as  regards  the  human 
species  has  also  been  applied  to  animals,  and 
that  either  parent  may  thus  influence  the  off- 
spring. Thus  it  is  asserted  that  the  male  race- 
horse when  excited  by  running,  if  not  fatigued, 
is  in  the  best  condition  for  communicating  speed 
to  his  offspring.    Again,  it  is  related  that  at 

*  More  recently  adopted  by  Mr.  Combe,  of  Edin- 
burgh, in  his  Work  on  the  Constitution  of  Man. 


the  time  when  a  stallion  was  about  to  cover  a 
mare,  the  stallion's  pale  colour  was  objected  to, 
whereupon  the  groom,  knowing  in  the  effect 
of  colour  upon  horses'  imaginations,  presented 
before  the  stallion  a  mare  of  a  pleasing  colour, 
which  had  the  desired  effect  of  determining  a 
dark  colour  in  the  offspring.  This  is  said  to 
have  been  repeated  with  success  in  the  same 
horse  more  than  once.  As  a  similar  case,  the 
influence  acting  through  the  mother,  it  is  related 
that  a  cow  belonging  to  a  farmer  of  Angus,  in 
Scotland,  had  been  grazing  in  company  with 
an  horned  ox  of  a  black  and  white  colour  for 
some  time  before  it  came  into  heat.  The  bull 
which  impregnated  the  cow  Had  no  horns,  and 
differed  totally  from  the  ox  in  colour,  as  did 
also  the  cow  itself ;  and  yet,  wonderful  to 
ralate,  the  next  calf  was  black  and  white,  and 
had  horns. 

These  stories  lead  us  to  the  consideration  of  a 
host  of  extraordinary  relations,  from  which  the 
general  conclusion  has  been  drawn,  by  no  very 
logical  process  of  induction,  that  the  imagina- 
tion of  the  female  parent  is  capable  of  exerting 
a  powerful  influence  on  the  structure  and  qua- 
lities of  the  offspring  either  at  the  moment  of 
conception  or  during  part  of  the  period  of  utero- 
gestation. 

The  effects  of  the  mother's  imagination  upon 
the  child  are  so  various  that  we  cannot  hope  to 
be  able  to  reduce  them  to  any  general  or  com- 
plete enumeration.  Those  which  have  attracted 
the  greatest  share  of  attention  are  of  the  nature 
of  blemishes,  spots,  wounds,  deficient  and  re- 
dundant parts,  in  short,  all  unnatural  or  so- 
called   monstrous   formations    of  the  child. 
The  alleged  causes  of  these  unnatural  for- 
mations include  all  those  circumstances  which 
powerfully  excite    the   moral  faculties,  the 
fancy,  desires,  or   passions  of  the  mother ; 
sudden  surprise,  fear,  anger,  horror  or  disgust 
on  her  being  a  witness  of  any  unusual  or 
frightful  event  or  object,  or  the  opposite  pas- 
sions of  joy,   pleasure,  admiration,  &c.  as 
well   as  strong  longings,  desires,  and  appe- 
tites, whether  satisfied  or  not.    The  influence 
of  the  mother's  imagination  upon  the  child 
is  not  confined  in  its  effects  to  bodily  disfigu- 
ration or  change,  however,  for  those  who  carry 
their  belief  its  whole  length  hold  that  the  mind 
of  the  child  may  also  be  similarly  modified. 
Thus  it  is  stated  that  the  ambition, courage,  and 
military  skill  of  Napoleon  Bonaparte  had  their 
foundation  in  the  circumstance  that  the  empe- 
ror's mother  followed  her  husband  in  his  cam- 
paigns, and  was  subjected  to  all  the  dangers  of 
a  military  life ;  while,  on  the  other  hand,  the 
murder  of  David  Rizzio  in  the  presence  of 
Queen  Mary  was  the  death-blow  to  the  personal 
courage  of  King  James,  and  occasioned  that 
strong  dislike  of  edged  weapons  for  which  that 
crafty  and  pedantic  monarch  was  said  to  be  re- 
markable. 

We  can  readily  believe  that  all  sudden 
or  violent  changes  in  the  functions  of  the  mo- 
ther, deranaements  of  the  general  circulation, 
nervous  affections,  and  other  circumstances 
which  tend  to  disturb  the  uterine  function, 
must  cause  or  be  liable  to  occasion  injury  to 


GENERATION. 


475 


the  foetus  or  its  coverings  during  pregnancy. 
So  also  we  can  understand  that  any  violent 
affection  of  the  mind  of  a  pregnant  woman,  in 
so  far  as  it  tends  to  derange  the  bodily  func- 
tions, may  produce  some  effect  on  the  nutrition 
of  the  child. 

Some  contagious  diseases  pass  from  the  mo- 
ther to  the  child  in  utero.  Syphilis  and  small- 
pox may  be  mentioned  as  those  the  effects  of 
which  have  been  most  frequently  observed.* 
Typhous  fever,  on  the  other  hand,  is  said  rarely 
to  affect  the  child.  We  know  also  that  severe 
affections  of  the  mother  may  cause  the  death  of 
the  child,  and  its  premature  expulsion  or  abor- 
tion. According  to  Hausmann,  the  effect  of 
variations  of  the  external  atmosphere  is  visible  in 
the  unusual  number  of  blind  colts  and  hydro- 
cephalic pigs  which  are  born  after  a  wet  sum- 
mer. Malformations  of  the  fcetus  of  birds  have 
been  artificially  produced  by  external  injuries 
and  altered  position  of  the  eggs  during  incuba- 
tion, f  The  transmission  to  the  child  of  the 
effects  of  chemical  poisons  taken  by  the  mother 
has  also  been  observed  ;  but  in  all  the  foregoing 
the  effect  of  the  injury  has  been  more  or  less 
general ;  and  there  is  no  sufficient  reason  to 
conclude  from  them  that  a  particular  impres- 
sion on  the  mind  of  the  mother  is  capable  of 
producing  physical  injury,  or  a  particular  de- 
formity in  one  or  other  of  the  organs  of  the 
foetus. 

A  vague  notion  is  entertained  by  some  that  a 
certain  influence  is  exerted  by  the  hen  or  other 
bird  on  the  eggs  that  they  incubate,  by  which 
the  qualities  of  the  progeny  are  modified.  But 
we  must  observe  that  hereditary  resemblances 
are  preserved  in  artificial  incubation  without 
the  hen  ;  and  although  we  are  disposed  to  ad- 
mit that  the  female  bird  incubates  its  eggs  with 
an  instinctive  care  and  perfection  that  art  can 
rarely  imitate,  we  are  exceedingly  sceptical  as 
to  the  possibility  of  any  other  secret  influence 
from  the  oviparous  mother  to  its  offspring 
once  the  eggs  have  left  the  body  ;  and  the 
attempt  to  support  the  theory  of  imagination  by 
this  opinion  is  an  explanation  of  the  obscurum 
per  obscurius. 

Were  it  possible  to  separate  the  better  authen- 
ticated from  the  more  fanciful  relations  of  the 
effects  of  the  mother's  imagination,  or  to  select 
those  instances  only  in  which  the  impression 
on  the  mind  of  the  mother  had  been  carefully 
noted  before  the  birth  of  the  child,  we  might 
expect  in  some  degree  to  be  able  to  free  this 
question  from  the  falsity  and  prejudice  which 
obscures  it.  But  such  a  separation  we  believe 
to  be  impossible,  and  we  have  therefore  re- 
solved to  enumerate  shortly  some  of  the  more 
remarkable  cases  taken  at  random, \  from  which 

*  In  reference  to  this,  it  is  an  interesting  circum- 
stance that  the  child  is  affected  with  small-pox 
some  time  after  the  mother,  as  if  the  contagion  had 
taken  the  same  time  to  operate  as  it  does  in  passing 
between  two  persons. 

t  As  in  Geoffory  St.  Hilaire's  experiments,  which 
the  author  has  more  than  once  repeated  with  a  si- 
milar result. 

i  From  Burdach's  Physiologic,  15.  ii.  and  from  a 
talented  Refutation  of  the  Doctrine  of  the  Imagina- 


we  think  the  reader  will  best  be  able  to  judge 
what  value  or  faith  is  to  be  attached  to  the  facts 
now  under  consideration. 

In  a  certain  number  of  these  cases  we  are 
told  that  an  injury  of  an  organ  in  the  mother 
causes  a  similar  injury  in  a  corresponding  part 
of  the  child's  body ;  as  in  the  following  ex- 
amples. 

1.  A  cow  killed  by  the  blow  of  a  hatchet  is 
found  pregnant  of  a  fcetus  with  a  bruise  on  the 
same  place  of  the  forehead. 

2.  The  same  was  the  case  with  the  young  one 
of  a  hind  that  had  been  shot. 

3.  A  pregnant  cat  which  had  had  its  tail 
trodden  on  bore  five  young,  in  four  of  which 
the  tail  was  similarly  wounded. 

4.  A  woman  bitten  on  the  pudenda  by  a  dog 
bore  a  boy  having  a  wound  of  the  glans  penis. 
This  boy  suffered  from  epilepsy,  and  when  the 
fits  came  on  during  sleep  was  frequently  heard 
to  call  aloud,  "  the  dog  bites  me ! "  There 
are  other  similar  cases  on  record. 

5.  A  pregnant  woman  walking  with  a  friend 
has  her  head  knocked  violently  against  her 
friend's,  and  shortly  afterwards  bears  twins, 
which  are  joined  together  by  the  foreheads. 

6.  A  gentlewoman  who  was  cut  for  rupture 
in  the  groin  during  her  pregnancy,  bears  a  boy 
having  a  large  scar  in  the  same  region,  which 
he  bore  for  thirty  years  afterwards. 

The  injuries  of  others  operating  on  the  ima- 
gination of  the  mother  may  affect  the  structure 
of  the  child  :  thus — 

7.  A  woman  who  was  suddenly  alarmed  by 
seeing  her  husband  come  home  with  one  side 
of  his  face  swollen  and  distorted  by  a  blow, 
bears  a  child  (a  girl)  with  a  purple  swelling 
covering  the  forehead,  nose,  &c.  of  the  same 
side. 

8.  A  child  is  born  with  hare-lip,  which  was 
caused  by  the  mother's  frequently  seeing  a 
child  with  the  same  deformity  during  her  preg- 
nancy. 

9.  A  mother  seeing  a  criminal  broke  upon 
the  wheel,  bears  an  idiot  child,  of  which  the 
bones  are  similarly  broken. 

10.  A  woman  seeing  a  person  in  an  epileptic 
fit  brings  forth  a  child  which  is  subject  to 
epilepsy. 

11.  A  lady  in  London,  who  is  frightened  by 
a  beggar  presenting  the  stump  of  an  arm  to  her, 
bears  a  child  wanting  a  hand. 

12.  A  child  is  born  with  its  head  pierced, 
in  consequence  of  its  mother  having  seen  a 
man  run  through  the  body  with  a  sword. 

13.  A  woman  is  forced  to  be  present  at  the 
opening  of  a  calf  by  the  butcher.  She  after- 
wards bears  a  child  with  all  the  bowels  hang- 
ing out  of  the  abdomen.  This  woman  was  at 
the  time  of  the  accident  aware  that  something 
was  going  wrong  in  the  womb. 

14.  A  similar  misfortune  happened  to  the 
child  of  another  woman,  who  was  imprudent 
enough  to  witness  the  disembowelling  of  a  pig 
during  her  pregnancy. 

tionists,  by  Dr.  Blundell,  of  London.  Professor 
Burdach,  we  may  remark,  is  inclined  to  adopt  the 
belief. 


476 


GENERATION. 


The  mere  description  of  an  event  may  affect 
the  child,  as  in  the  following  curious  case. 

15.  A  woman  who  had  listened  with  con- 
siderable interest  to  a  description  of  the  ope- 
ration of  circumcision  bears  a  child  with  the 
foreskin  split  up  and  turned  back  ! 

16.  A  woman  who  sees  another  affected  with 
prolapsus  uteri  bears  a  child  affected  with  the 
same  disease. 

The  examples  of  the  effect  of  sudden  fright, 
disgust,  anger,  joy,  &c.  are  very  numerous. 

17.  A  lady  absent  from  home  is  alarmed  by 
seeing  a  great  fire  in  the  direction  of  and  near 
her  own  house ;  and  some  months  afterwards 
bears  a  female  child  having  the  distinct  mark 
of  a  flame  on  her  forehead. 

18.  A  pregnant  woman  frighted  by  her  hus- 
band pursuing  her  with  a  drawn  sword,  bears 
a  child  with  a  large  wound  in  the  forehead. 

19.  A  man  who  had  personated  a  devil 
(or  satyr  according  to  other  authorities)  goes  to 
bed  in  his  assumed  dress,  and  his  wife,  being 
then  pregnant,  afterwards  bears  a  child  having 
horns,  cloven  feet,  &c. 

20.  A  mother  frighted  by  the  firing  of  a  gun 
has  a  child  wounded  as  by  a  gun-shot. 

21.  A  pregnant  woman  falls  into  a  violent 
passion  at  not  being  able  to  obtain  a  particular 
piece  of  meat  at  a  butcher's  shop ;  she  bleeds 
at  the  nose,  and  wiping  the  blood  from  her  lip, 
afterwards  bears  a  child  wanting  the  lip. 

22.  A  woman  two  months  before  being 
brought  to  bed  is  alarmed  by  hearing  a  report 
that  a  neighbour  had  murdered  his  wife  by  a 
wound  on  the  breast,  and  bears  a  child  with  a 
similar  wound. 

23.  A  child  is  born  with  the  hair  of  one 
side  black,  that  of  the  other  white:  competent 
judges  declared  at  the  time  that  both  sides 
would  have  been  white,  but  for  the  circum- 
stance that  the  mother  had  carried  a  heavy  sack 
of  coals  during  her  pregnancy. 

24.  A  woman  frighted  by  the  sudden  ap- 
pearance of  a  negro  brings  forth  a  child  with 
various  black  marks. 

25.  A  mother  is  suddenly  frighted  by  a 
lizard  jumping  into  her  breast,  and  afterwards 
gives  birth  to  a  child  having  a  fleshy  excre- 
scence exactly  like  a  lizard  growing  from  the 
breast,  to  which  it  adhered  by  the  head  or 
neck. 

26.  A  child  has  a  face  exactly  like  a  frog's, 
from  the  mother  having  held  a  frog  in  her  hand 
about  the  time  of  conception. 

27.  The  remarkable  resemblance  of  a  wo- 
man to  an  ape  was  fully  accounted  for  by  her 
mother  having  been  much  pleased  with  one  of 
these  animals  when  with  child  of  her. 

The  effect  of  the  attentive  contemplation  of 
pictures,  statues,  &c.  by  pregnant  women  is 
worthy  of  notice. 

28.  A  chi^d  is  born  covered  with  hairs  in 
consequent'  of  the  mother  having  been  in  the 
habit  of  "beholding  a  picture  of  St.  John  the 
Baptist. 

29.  A  woman  gives  birth  to  a  child  covered 
with  hair  and  having  the  claws  of  a  bear,  from 
her  constantly  beholding  the  images  and  pic- 
tures of  bears  hung  up  every  where  in  the 


dwelling  of  the  Ursini  family,  to  which  she 
belonged.  It  is  not  stated  by  the  Author  of 
Waverley,  whether  any  thing  of  the  kind  ever 
happened  in  the  Bradwardine  family. 

30.  A  woman  contemplating,  too  earnestly 
as  it  appears,  a  picture  of  St.  Pius,  has  after- 
wards a  child  bearing  a  striking  resemblance  to 
an  old  man. 

3 1 .  The  tyrant  Dionysius  was  aware  of  the 
effect  of  pictures ;  for  he  hung  a  beautiful 
picture  in  his  wife's  chamber,  in  order  to  im- 
prove his  children's  looks. 

32.  Two  girls  (twins)  were  born  with  their 
bodies  joined  together,  their  mother  having 
during  her  pregnancy  been  in  the  habit  of  at- 
tentively contemplating  two  sacred  images 
similarly  placed. 

33.  A  child  is  born  with  its  skin  all  mottled 
in  colour  from  the  mother  having  made  a  visit 
to  St.  Winifred's  Well,  and  seeing  the  red  peb- 
bles there. 

34.  Another  child  was  marked  on  the  face, 
in  consequence  of  the  mother  having  worn 
black  patches. 

The  longings  and  depraved  appetites  to 
which  pregnant  women  are  liable  are  occa- 
sionally the  causes  of  marks  and  deformities 
in  their  children. 

35.  There  are  a  great  many  instances  in 
which  the  longing  of  the  mother  after  straw- 
berries, grapes,  cherries,  peaches,  and  other 
fruits  has  caused  the  growth  of  tumours  in  the 
children  exactly  resembling  in  each  the  fruit 
that  was  wished  for, 

36.  A  woman  who  had  longed  for  a  lobster 
brings  forth  a  child  much  resembling  one  of 
these  animals. 

37.  Another  woman  had  a  female  child,  the 
head  of  which  was  like  a  shell-fish  (a  bivalve, 
which  opened  and  shut  as  a  mouth),  which 
proceeded  from  the  mother's  having  had  a  strong 
desire  for  mussels  at  one  time  of  her  preg- 
nancy. 

38.  A  pregnant  woman  longs,  or  has  a  great 
desire  to  bite  the  shoulder  of  a  baker  who 
happens  to  pass.  The  husband,  wishing  to 
humour  this  extraordinary  fancy,  hires  the  baker 
to  submit  to  be  bitten.  The  mother  makes 
two  bites,  but  of  such  a  kind  that  the  baker 
will  not  submit  to  more;  and  some  time  after- 
wards she  is  brought  to  bed  of  three  children, 
one  dead  and  two  living. 

39.  A  case  of  spina  bifida  near  the  sacrum 
is  explained  by  the  mother's  having  wished  for 
fritters,  and  not  obtaining  them,  having  ap- 
plied her  hand  (we  know  not  with  what  object) 
to  a  corresponding  place  in  her  own  body. 

The  impression  on  the  fancy  of  the  mother 
may  be  made  before  conception  has  taken 
place :  thus — 

40  A  woman,  whose  children  had  pre- 
viously been  healthy,  six  weeks  before  con- 
ception is  suddenly  frighted  by  a  beggar  who 
presents  a  stumped  arm  and  a  wooden  leg,  and 
threatens  to  embrace  her :  the  next  child  had 
only  one  stump  leg  and  two  stump  arms. 

The  impression  on  the  fancy  may  extend  to 
the  product  of  several  successive  conceptions. 

41.  A  young  woman  frighted  in  her  first 


GENERATION. 


477 


pregnancy  by  the  sight  of  a  child  with  hare-lip, 
bears  a  child  with  a  complete  deformity  of  the 
same  kind :  her  second  child  had  merely  a 
deep  slit,  and  her  third  no  more  than  a  mark 
in  the  same  place. 

We  do  not  wish  to  argue  against  this  hy- 
pothesis from  its  prima  facie  absurdity  merely; 
but  we  think  it  will  be  generally  admitted  that 
the  greater  number  of  the  foregoing  cases  are 
ridiculous  and  incredible ;  inasmuch  as  simple 
malformations  of  structure  well  known  to  ana- 
tomists have  been  rfgarded  as  the  represen- 
tations of  animals  and  other  objects  to  which 
they  bear  a  very  distant  if  any  resemblance, — 
cases,  in  short,  in  which  it  is  apparent  that  the 
imagination  of  the  bye-standers  has  been  more 
active  than  that  of  the  mother. 

We  shall  at  once  admit  that  we  ought  not  to 
reject  immediately  an  explanation  of  the  me- 
chanism of  a  vital  function  on  account  of  its 
obscurity  merely  ;  but  we  assert  that  the  gene- 
ral phenomena  of  the  vital  functions  are  capa- 
ble of  being  observed  and  reduced  to  fixed 
and  general  laws,  which  is  certainly  by  no 
means  the  case  with  the  effects  of  imagination, 
which  are  as  various  and  contradictory  as  they 
are  absurd  and  ridiculous.  The  anatomical 
connection  of  the  maternal  uterus  and  child  is 
so  well  known  that  we  may  with  safety  affirm 
that  no  such  communication  exists  as  would 
be  necessary  for  the  transmission  of  an  im- 
pression from  the  body  of  the  mother  to  any 
particular  organ  of  the  foetus,  and  much  less 
any  means  of  conveying  mental  impressions 
only.  The  longings  which  are  said  to  be  so 
liable  to  cause  injuries  of  the  child  seem  to 
act  in  the  same  manner  whether  the  appetite 
is  satisfied  or  not,  &c. 

But  moral  reasons  are  much  stronger  against 
the  belief.  It  is  obvious  that  in  much  the 
larger  proportion  of  the  cases  related,  the  co- 
incidence of  the  mental  impression  on  the 
mother  with  the  injury  done  to  the  child  is  a 
post-partum  observation  and  discovery.  The 
mother  and  her  friends,  or  the  father,  if  such  a 
deformity  shall  belong  to  his  side  of  the  house, 
are  desirous  of  finding  an  explanation  of  the 
blemish  which  shall  not  be  a  stigma  upon 
them;  and  in  other  instances  it  is  to  be  feared 
that  the  idle  and  talkative  women  who  attend 
upon  child-beds,  and  even  more  scientific  male 
accoucheurs,  have  encouraged  the  mother's 
belief  in  the  effect  of  some  alleged  previous 
impression  (selected  from  thousands)  on  her 
imagination,  in  order  to  hide  undue  violence 
employed  during  the  delivery,  or  perhaps  with 
a  less  culpable  desire  to  quiet  the  fears  of  the 
mother  while  in  the  dangerous  puerperal  state. 

There  is  no  doubt  that  there  are  innumerable 
instances  in  which  the  imagination  and  all  the 
moral  and  intellectual  powers  of  women  have 
been  highly  excited  during  pregnancy  without 
their  children  having  suffered  in  any  respects  ; 
and  there  are  not  wanting  instances  of  chil- 
dren being  born  with  all  kinds  of  deformity 
that  have  been  attributed  to  the  effect  of 
imagination,  without  their  being  aware  of  any 
unusual  impression  having  been  made  on  their 
minds. 


Again,  it  may  be  remarked  that  the  stage  of 
the  period  of  pregnancy  at  which  the  injury  of 
the  child  may  take  place  is  by  no  means  de- 
fined, and  that  there  is  no  correspondence 
between  the  time  or  advancement  of  the  foetus 
and  the  nature  of  the  injury.  Some  injuries 
are  said  to  have  occurred  or  to  have  had  their 
foundation  laid  at  the  very  moment  of  con- 
ception, and  even  occasionally  before  that  time, 
while  others  are  inflicted  only  a  few  weeks  be- 
fore birth. 

The  monstrous  appearances  or  malformations 
which  constitute  by  far  the  greater  part  of  the 
injuries  attributed  to  the  mother's  imagination, 
are  now  no  longer  regarded  as  lusus  naturae 
merely,  or  "  sports  of  nature's  fancy,"  as  they 
used  to  be  called ;  but  the  times  at  which 
many  of  them  must  have  occurred  are  known 
with  some  degree  of  certainty,  and  these  times 
by  no  means  correspond  with  the  periods  at 
which  the  imagination  is  said  to  have  been 
affected.  Besides  this,  nearly  the  whole  of 
congenital  malformations  have  been  accurately 
anatomised,  and  their  structure  is  reduced  to 
general  laws  as  regular  and  determinate  in 
each  individual  form  as  the  more  usual  or  so- 
called  natural  structure.    See  Monstrosity. 

In  this  question,  as  in  others  of  a  like  kind, 
reference  has  been  made  to  scriptural  autho- 
rity, in  the  history,  viz.  of  Jacob's  placing  the 
peeled  black  and  willow  rods  before  the  ewes 
which  went  to  drink  and  afterwards  conceived. 
But  any  one  who  pays  the  slightest  attention 
to  the  whole  of  this  relation  will  at  once  be 
convinced  that  the  sacred  writer,  in  describing 
the  proceeding  of  Jacob,  exhibits  merely  that 
patriarch's  belief  in  the  efficacy  of  such  means; 
for  in  a  subsequent  part  of  the  chapter  Jacob 
is  undeceived  by  the  angel,  who  appears  to  him 
in  a  dream  and  informs  him  of  the  real  cause 
of  the  multiplication  of  the  speckled  lambs, 
&c.  viz.  the  circumstance  that  the  ring-straked, 
speckled,  and  spotted  males  had  leaped  upon 
the  females,  and  that  the  progeny  therefore 
merely  inherited  their  colour  from  their  fathers. 

We  now  leave  this  unsatisfactory  subject, 
upon  which  we  have  perhaps  dwelt  longer  than 
it  deserves.  We  have  introduced  the  foregoing 
remarks  partly  in  accordance  with  custom,  and 
also  with  a  view  to  shew  how  little  connection 
exists  between  the  facts  of  our  subject  and  the 
vague  fancies  to  which  allusion  has  been  made. 
In  doing  so  we  are  aware  that  we  are  liable  to 
the  accusation,  on  the  one  hand,  of  having 
treated  with  too  much  levity  facts  and  ob- 
servations upon  which  some  are  disposed  im- 
plicitly to  rely,  and,  on  the  other,  of  trifling 
with  science  in  noticing  even  such  vain  fancies 
as  belong  to  pregnant  women  and  their  atten- 
dant nurses. 

We  conclude  by  adopting  and  expressing 
the  opinion  of  Dr.  Blundell,  "  that  it  is  con- 
trary to  experience,  reason,  and  anatomy  to 
believe  that  the  strong  attention  of  the  mother's 
mind  to  a  determinate  object  or  event  can 
cause  a  determinate  or  a  specific  impression 
upon  the  body  of  her  child  without  any  force 
or  violence  from  without;  and  that  it  is  equally 
improbable  that,  when  the  imagination  is  ope- 


478 


GENERATION. 


rating,  the  application  of  the  mother's  hand  to 
any  part  of  her  own  body  will  cause  a  dis- 
figuration or  specific  impression  on  a  corres- 
ponding part  of  the  body  of  the  child." 

§  3.  Number  of  children ;  and  relative 
proportion  of  the  male  and  J'emale  sexes. 

The  simpler  animals  are,  generally  speaking, 
more  fruitful  than  the  complicated  ones.  As 
examples  of  great  fecundity,  may  be  mentioned 
some  of  the  Entozoa  and  Mollusca,  which  pro- 
duce hundreds  of  thousands  of  ova  ;  among 
Crustacea  and  Insects  some  produce  many 
thousand  young.  The  Perch  and  Cyprinus 
genus  among  fishes  produce  some  hundreds  of 
thousands,  and  the  common  Cod,  it  is  said, 
some  millions  of  ova.  Most  of  the  Batrachia 
produce  at  least  some  hundreds.  But  in  the 
warm-blooded  Vertebrata,  the  necessity  of  in- 
cubation or  utero-gestation  puts  a  limit  to  the 
number  of  young  ;  and  there  are  also  compara- 
tively few  in  the  Blenny,  Skate,  Shark,  Land 
Salamander,  or  such  animals  as  are  ovo-vivi- 
parous. 

In  the  humau  female,  the  number  of  chil- 
dren altogether  produced  is  limited,  first,  by 
the  number  of  Graafian  vesicles  in  the  ovaries, 
which  usually  amounts  to  from  twelve  to  fif- 
teen in  each  ovary  ;  and  second,  by  the  length 
of  the  time  during  which  a  woman  bears  chil- 
dren, (the  greatest  extent  of  which  is  usually 
twenty-five  years,  that  is,  from  the  age  of  fifteen 
to  forty,  or  twenty  to  forty-five,)  the  length  of 
this  period  again  depending  upon  the  rapidity 
with  which  the  births  succeed  one  another,  and 
the  number  of  children  produced  at  each. 

Women  most  frequently  bear  every  twenty 
months,  but  some  have  children  at  shorter  in- 
tervals, as  of  fifteen  or  even  twelve  months. 
This  often  depends  upon  the  circumstance 
that  in  some  lactation  prevents  conception ; 
in  others  it  does  not. 

The  number  of  the  eggs  of  birds  for  one  in- 
cubation varies  from  two  to  sixteen.  The  num- 
ber of  the  young  of  Mammalia  produced  in 
one  utero-gestation  varies  from  one  to  fifteen, 
and  occasionally  more. 

Woman  usually  bears  a  single  child.  The 
proportion  of  twin-births  to  those  of  single 
children  is  estimated  by  Burdach  as  one  to 
seventy  or  eighty  :  the  proportion  of  triplet 
births  one  to  six  or  seven  thousand  ;  quadru- 
plets, one  to  twenty  or  fifty  thousand.  Occa- 
sionally five  children  come  at  one  birth,  and 
there  are  instances  on  record  of  six  or  even 
seven  children  being  born  at  once. 

The  causes  of  this  greater  or  less  fecundity 
are  not  known  :  they  are  in  all  probability 
various;  being  not  of  an  accidental  nature, 
but  connected  with  the  constitution  of  one 
or  other  of  the  parents,  most  frequently  per- 
haps of  the  mother. 

A  healthy  woman  bearing  during  the  whole 
time,  and  with  the  common  duration  of  inter- 
val, may  have  in  all  from  twelve  to  sixteen  chil- 
dren ;  but  some  have  as  many  as  eighteen  or 
twenty ;  and  when  there  are  twins,  &c.  con- 
siderably more,  as  in  the  following  remarkable 
instances.  First,  eighteen  children  at  six  births. 
Second,  forty-four  children  in  all,  thirty  in  the 


first  marriage,  and  fourteen  in  the  second ;  and 
in  a  still  more  extraordinary  case,  fifty-three 
children  in  all  in  one  marriage,  eighteen  times 
single  births,  five  limes  twins,  four  times  tri- 
plets, once  six,  and  once  seven.* 

Men  have  been  known  to  beget  seventy  or 
eighty  children  in  two  or  more  marriages,  but 
the  tendency  of  polygamy  is  generally  believed 
to  be  to  diminish  rather  than  to  increase  the 
number  of  the  whole  progeny. 

According  to  Marc,  not  more  than  two  or 
three  children  are  born  from  two  thousand  pros- 
titutes in  the  course  of  a  year, — a  circumstance 
depending  in  part  on  their  want  of  liability  to 
conception,  and  in  part  on  frequent  abortion. 

The  proportion  of  children  born  in  each  mar- 
riage varies  much  in  different  countries.  The 
following  statement  of  the  average  number  is 
taken  from  Burdach :  Germany,  6 — 8  ;  Eng- 
land, 5 — 7;  France,  4 — 5;  Spain  and  Italy, 
2— 3.f 

In  reference  to  the  average  proportion  of  male 
and  female  births,  it  appears  from  very  exten- 
sive data  that  in  this  and  most  other  countries 
the  number  of  males  usually  exceeds  that  of 
females ;  in  this  country  in  the  proportion  of 
four  or  five  in  a  hundred. 

The  circumstances  which  influence  the  pre- 
ponderance of  male  births  are  not  known.  The 
accompanying  table  shews  how  very  constant 
it  is  in  different  countries. 

Table  of  the  proportional  number  of  males 
and  females  born  in  different  countries ;  the 
females  being  taken  as  100. 

Great  Britain   104.75 

^  f  106.55 

FranCe ( 103.38 

Prussia   {ISqo 

Sweden   104.72 

Wurtemburg  . .  105.69 

Westphalia  and  Rhine  ....  105.86 

Bohemia   105.38 

Netherlands   106.44 

Saxony  and  Silesia   106.05 

Austria   106.10 

Sicily   106.18 

Brandenburg   106.27 

Mecklenburg   107.07 

Mailand   107.61 

Russia   108.91 

Jews  in  Prussia   112. 

 in  Breslau   114. 

 in  Leghorn   1 20. 

Christians  in  Leghorn   104. 

It  has  been  found,  on  the  other  hand,  that  the 
first  children  of  a  marriage  consist  of  a  greater 
number  of  females  and  fewer  males,  in  the  pro- 
portion, according  to  Burdach,  of  fifty-three 
male  births  to  a  hundred  females.  A  similar 
preponderance  of  females  is  said  to  exist  among 
illegitimate   children ;  but  the  difference  is 

ff  See  Fournier,  Diet,  des  Scien.  Med.  torn  iv. 

+  According  to  Burdach,  one  marriage  out  of 
fifty  is  unfruitful ;  there  is  one  birth  on  an  average 
for  every  twenty-five  of  the  population  of  a  place  ; 
and  taking  the  whole  population  of  the  world  at  six 
hundred  and  thirty-three  millions,  about  fifty-one 
children  are  born  every  second  ! 


GENERATION. 


479 


much  less,  not  amounting  to  move  than  four  or 
six  in  one  hundred.* 

Malformations  are  said  to  occur  more  fre- 
quently among  illegitimate  than  legitimate  chil- 
dren ;  and  malformed  children  are  more  fre- 
quently of  the  female  sex.  This,  together  with 
the  circumstance  that  illegitimate  children  are 
oftenest  first  born,  may  in  some  degree  account 
for  the  greater  number  of  females  among  them. 

The  data  upon  which  it  has  been  attempted 
to  found  an  explanation  of  the  cause  of  the 
formation  of  a  male  or  female  offspring  are  very 
slender  indeed  ;  nor  are  we  likely  ever  to  ob- 
tain knowledge  which  shall  enable  us  to  form  a 
satisfactory  theory  regarding  the  cause  of  the 
determination  of  the  sex.  Some  men  beget 
always  male  children,  others  always  females,  in 
more  than  one  marriage.  The  same  seems 
sometimes  to  depend  on  the  mother.  In  other 
marriages  children  of  one  sex  are  born  for  a 
time,  and  subsequently  those  of  the  other  ;  or 
the  male  and  female  children  may  alternate, 
&c.  8cc.  without  our  being  able  to  point  out  any 
circumstance  which  has  given  rise  to  the  pro- 
duction of  one  or  other  sex. 

Accordingly  many  vague  opinions  have  been 
entertained  regarding  this  subject,  as  for  exam- 
ple the  following  : 

1.  That  the  wishes  or  ideas  of  the  parents  at 
the  time  of  conceptions  may  influence  the  sex 
of  the  offspring. 

2.  The  nature  of  the  food  of  the  parents,  par- 
ticularly of  the  mother  during  pregnancy. 

3.  The  use  of  various  medicines  :  hence  the 
numerous  charms  and  recipes  for  begetting 
children  of  either  sex. 

4.  The  quantity  of  oxygen  absorbed  during 
development. 

5.  The  manner  in  which  the  spermatic  artery 
is  given  off  from  the  aorta,  and 

6.  The  older  and  equally  groundless  notion 
that  male  children  come  from  the  right  testicle 
or  ovary,  and  females  from  the  left ;  upon 
which  hypothesis  was  founded  the  celebrated 
advice  of  Hippocrates  :  "  Ubi  femellam  gene- 
rare  volet  (pater)  coeat,  ac  dextram  testem  obli- 
ge!, quantum  id  tolerare  poterit,  sed  si  ma- 
rem  generare  appetat,  sinister  testis  obligandus 
erit." 

A  belief  has  long  prevailed  that  the  greater 
the  strength  of  either  of  the  parents  in  propor- 
tion to  the  other,  the  more  of  its  own  sex  will 
be  generated.  M.  Girou  de  Buzaraignes  has 
paid  considerable  attention  to  the  influence  of 
age,  strength,  mode  of  life,  &c.  of  the  parents 
on  the  sex  of  the  offspring,  and  has  made  a 
series  of  experiments  on  the  domestic  animals, 
from  which,  should  they  be  confirmed,  some 
important  results  may  be  expected. 

According  to  M.  Girou,-|-  male  fathers  among 
the  domestic  animals  which  are  either  too  old 
or  too  young,  produce  with  mature  and  healthy 
females  more  female  than  male  offspring  ;  while 
female  parents  that  are  too  old  or  too  young  in 
proportion  to  the  males  bear  most  males.  This 


*  Illegitimate  Children  . 

Legitimate  ditto 
t  Sur  la  Generation. 


France.  Prussia.  Hamburg. 
Buys.    Boys.    Boys.  Girls- 

..104-    102-  94-, 
.106-    106-    105  /  100 


would  appear  to  be  the  case  in  the  human 
species  also  from  the  observations  of  Hofacker 
at  Tubingen,  and  of  Saddler  on  the  English 
peerage  :  the  children  of  a  husband  consider- 
ably younger  than  his  wife  being  nearly  in  the 
proportion  of  ninety  sons  to  a  hundred  daugh- 
ters ;  while  those  of  the  husband  considerably 
older  than  the  mother  are  in  the  proportion  of 
a  hundred  and  fifty  or  a  hundred  and  sixty  sons 
to  a  hundred  daughters  ;  the  intermediate  ages 
being  found  to  give  a  proportionate  scale. 

Burdach  states  that  those  women  who  are 
most  fruitful  bear  many  more  boys  than  girls, 
as  in  the  following  examples  : — 

Boys.  Girls. 

1st  woman  bore   26  6 

2nd  ditto,  in  first  marriage  ....   27  3 

in  second  ditto   14  0 

3rd  ditto   38  15 

According  to  Girou,  female  domestic  animals 
bear  more  females  when  well  nourished  and 
left  in  repose  than  when  much  worked  and  on 
spare  diet ;  and  it  has  been  alleged  that  the 
sexes  of  plants  are  influenced  by  their  nourish- 
ment or  soil  in  which  they  grow  ;  dioecious 
plants  having  seeds  which  propagate  more 
males  in  dry  ground  exposed  to  the  sun,  more 
females  in  moist,  well  manured,  and  shady 
ground ;  monoecious  plants  bearing  more  of 
the  staminiferous  or  pistilliferous  flowers  in  cor- 
responding circumstances.  XQ^J- — 

The  explanation  of  the  cause  of  this  variation 
of  the  sex  as  well  as  of  the  original  sexual  dif- 
ference, it  has  already  been  remarked,  is  beyond 
the  reach  of  investigation.  Very  interesting 
observations  have,  however,  brought  to  light 
the  different  steps  of  the  process  by  whicli  the 
generative  organs  of  either  sex  are  gradually 
formed  during  the  development  of  the  foetus; 
and  a  series  of  facts  has  thus  been  established 
of  great  interest  and  importance  as  tending  to 
elucidate  the  nature  of  those  numerous  remark- 
able malformations  of  the  reproductive  organs 
generally  comprehended  under  the  term  Her- 
maphrodism.  We  refer  the  reader  to  the  article 
upon  this  subject,  and  to  that  of  Ovum,  for  a 
history  of  the  process  now  alluded  to,  and 
shall  not  do  more  than  merely  mention  in  this 
place  some  of  the  more  important  results  which 
have  been  obtained. 

1st.  It  appears  that  in  the  earliest  stages  of  foetal 
life,  the  sexes  (or  what  may  become  afterwards 
either  male  or  female,  that  is,  all  the  young)  are 
perfectly  alike  in  structure. 

2nd.  That  there  exists  in  all  a  common  ma- 
trix or  rudimentary  organ  or  set  of  organs, 
which  at  a  later  period  is  converted  by  deve- 
lopment into  the  male  or  female  organs. 

3rd.  That  the  early  type  of  the  sexual  organs 
is  to  be  regarded  as  common  and  single,  rather 
than  double,  as  some  have  considered  it. 

In  conclusion,  we  may  remark  that  we  must 
confess  ourselves  equally  unable  to  fathom  the 
nature  of  the  original  bias  or  determination 
given  by  the  parents,  in  consequence  of  which 
a  male  or  a  female  child  is  produced,  and  to 
ascertain  the  manner  in  which  any  other  here- 
ditary influence,  quality,  or  conformation  is 
transmitted  from  the  parent  to  its  offspring. 
At  the  same  time  it  appears  not  improbable 


480 


GLAND. 


that  the  nature  of  the  sex  may  in  some  degree 
be  modified  by  circumstances  affecting  the 
female  at  an  early  period  of  utero-gestation. 
In  reference  to  this  subject  we  ought  not  to 
omit  the  mention  of  a  fact  which  is  well  esta- 
blished, viz.  that  when  the  cow  bears  two  calves, 
one  of  which  is  a  male,  the  other,  exteriorly  re- 
sembling- the  female,  has  its  reproductive  organs 
internally  imperfectly  formed,  being  of  that 
kind  of  hermaphrodite  formation  usually  called 
the  Free  Martin.* 

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vazioni  microscopiche  concernenti  il  systema  di 
generazione  de  Sig.  Needham  e  Buffon,  Modena, 
1765.  Memorie.  sopra  i  muli  di  varii  autori,  Mo- 
dena, 1768.  Sandifort,  De  ovo  humano,  in  Ej. 
Obs.  pathol.  lib.  iii.  Senebier,  Experiences  pour 
servir  a  l'histoire  de  la  generation,  &c.  de  Spal- 
lanzani, &c.  &c.  Genev.  1785.  Blumenbach,  De 
nisu  formativo  Comm.  Gotting.  vol.  viii.  p.  41. 
Denrnan,  Collection  of  engravings,  Lond.  1787. 
Zroeifel,  Uber  die  Entwickelungstheorie,  ein  brief 
an  H.  Senebier,  Gotting.  1788.  Mohrenheim,  Nova 
conceptus  atque  generationis  theoria,  Kbnigsberg, 
1789.  Grasmeyer,  De  conceptione  et  fecundatioue, 
et  Supplementa,  Gotting.  1789.  Speculations  on 
the  mode,  &c.  of  impregnation,  Edinb.  1789. 
Fontana,  Lettera  ad  un  amico  sopra  il  systema  degli 
soilluppi,  Firenze,  1792;  Transl.  intoReil'sArchiv. 
Band.  ii.  Haighton,  On  the  impregnation  of  ani- 
mals, Philos. Trans.  1797  ;  Transl.  in  Reil's  Archiv. 
Bd.  3d.  Ludwig,  De  nisu  formativo,  Lips.  1801. 
Vicq  d'Axyr,  Anat.  et  phys.  de  l'ceuf,  in  CEuvres, 
t.  iv.  Pulley,  On  the  proximate  cause  of  impreg- 
nation, Lorrd.  1801.  Oken,-  Zeugung,  Hamb.  u. 
Wurzb.  1805.  Prevost  et  Dumas,  Nouv.  theorie  de 
generation,  in  Annates  des  Sciences  Naturelles, 
1825.  The  various  systems  of  Physiology,  but 
especially  Treviranus,  Burdach,  vol.  i.,  and  Hal- 
ler's  Elementa. 

( Allen  Thomson.) 

*  See  John  Hunter's  well  known  paper  on  the 
Free  Martin  in  his  Animal  GSconomy,  new  ed.  by 
Owen,  1838. 


GLAND,  Gr.  a^»;  Lat.  Glandula;  Fr. 
Glande;  Germ.  Druse. 

An  organ  whose  office  is  to  separate  from  the 
blood  a  peculiar  substance,  almost  invariably 
fluid  ;  constantly  provided  with  an  excretory 
duct ;  formed  of  a  process  of  the  mucous  mem- 
brane or  of  the  skin,  disposed  either  in  the  form 
of  a  sac  or  of  a  ramified  canal ;  which  sac  or 
canal  in  all  cases  is  closed  by  a  blind  extremity  ; 
and  which,  although  amply  supplied  with  blood, 
is  never  directly  continuous  with  the  bloodves- 
sels.* It  is  absolutely  necessary  to  give  this 
definite  explanation  of  the  meaning  which  is 
attached  to  the  word  gland  in  the  present  article, 
inasmuch  as  there  is  no  term  in  anatomy  that 
has  been  more  vaguely,  and  as  it  appears  to  me 
more  incorrectly  employed. 

It  is  not  necessary  to  point  out  the  absurdity 
of  applying  this  word  to  certain  parts  of  the 
brain,  or  to  the  masses  of  fat  contained  in  the 
joints,  which  were  called  by  the  older  anato- 
mists glands  ;  in  these  instances  the  fallacy  is 
immediately  apparent;  but  there  are  other 
errors  which,  although  less  striking,  are,  I  con- 
ceive, no  less  injurious  in  their  effects.  Thus 
in  the  glandular  system  many  continental  au- 
thorities include  not  only  the  liver,  kidneys, 
salivary  glands,  and  other  organs,  which  are 
universally  acknowledged  to  belong  to  this 
class ;  but  likewise  the  lymphatic  glands,  the 
thyroid,  the  thymus,  the  spleen,  the  supra- 
renal capsules,  and  the  ovaries.f    It  is  con- 

*  The  only  real  exception  to  this  law  is  the  testicle 
of  fishes,  in  which  no  excretory  duct  seems  to  exist. 

t  Bichat,  after  condemning  the  application  of 
the  term  to  the  thyroid,  the  pineal  gland,  the 
lymphatic  glands,  &c.  states,  "  we  ought  only  to 
call  those  glands,  which  pour  out  by  one  or  several 
ducts,  a  fluid  which  these  bodies  separate  from  the 
blood  they  receive  by  their  vessels."  Anat.  Gen. 
torn.  ii.  p.  598. 

Meckel,  on  the  contrary,  objects  to  the  opinion 
that  an  excretory  duct  is  essential  to  a  gland.  Ac- 
cording to  his  definition  the  glandular  system  com- 
prises, 1.  the  mucous  glands  ;  2.  the  sebaceous 
glands  ;  3.  the  liver,  the  salivary  glands,  the  pan- 
creas, the  lachrymal  glands,  the  tonsils,  testes,  the 
ovaries,  the  prostate,  Cowper's  glands,  the  kidneys  ; 
4.  the  lymphatic  glands,  the  thyroid,  the  mammary 
glands,  thymus,  spleen,  supra-renal  capsules. 
Man.  d'Anat.  torn.  i.  p.  511. 

It  is  surprising  that  so  admirable  a  physiologist 
as  Meckel  should  adopt  this  opinion. 

Professor  Miiller  has  also  a  classification,  which 
seems  to  me  objectionable  ;  for  he  has  admitted 
among  the  glands  the  spleen,  thyroid,  lymphatic 
glands,  &c.  It  must  not,  however,  be  supposed 
from  this  arrangement  that  this  profound  anatomist 
considers  these  particular  bodies  as  real  glands. 
His  classification  is  as  follows.  (Handbuch  der 
Physiol,  des  Menschen,  Coblenz,  1.834,  p.  418.) 

«  f  A.  Ganglia  sanguineo- vasculvsa,  the 
o  I  spleen  in  the  digestive  organs — the  su- 
|3  %  pra-renal  capsules  in  the  genital  and 
1  uro-poietic  viscera — the  thymus  and 
J§  ^  \  thyroid  in  the  respiratory  apparatus — ■ 
§  «      J  glandula  choroidals  in  the  eye — the 

m  placenta  in  the  fcetus. 

f  B.  G.  lymphatico-vasculosa,  the  lym- 
M  phatic  and  mesenteric  glands. 


5  *  o  3  f 

f-1  .g  *  "°  >    Liver,  salivary  glands,  testis,  &c. 

w  .2  ts  2  J 

60 


GLAND. 


481 


tended  by  these  writers  that  the  last  named 
bodies  elaborate  from  the  blood  certain  fluids, 
and  that  as  far  as  the  real  function  of  a  gland  is 
concerned,  it  matters  not  whether  the  secreted 
fluid  escapes  by  a  proper  excretory  duct,  or  is 
taken  up  by  the  lymphatic  vessels;  it  is,  in- 
deed, supposed  by  Haase  that  these  bodies, 
like  the  true  glands,  possess  excretory  ducts, 
but  this  opinion  has  received  little  support. 

This  method  of  viewing  the  subject  appears 
to  be  very  injudicious  ;  because  it  is  based  on 
the  assumption  that  certain  organs  secrete  fluids 
from  the  blood,  but  of  which  secretion  we  have 
no  evidence  ;  and  further,  because  organs  are 
classed  together,  between  which  there  is  no 
similarity  either  of  structure  or  of  function. 

In  establishing  a  well-founded  distinction 
between  parts  which,  in  their  general  form  and 
outward  appearance,  bear  a  resemblance  to 
each  other,  it  is  proper  to  seek  for  some  lead- 
ing and  obvious  character,  concerning  which 
there  can  be  no  dispute.  In  applying  this  rule 
to  the  presenUcase,  we  shall  find  that  the  spe- 
cial distinction  of  a  true  gland,  as  contrasted 
with  those  organs  with  which  it  has  been  assi- 
milated, is  the  possession  of  an  excretory  canal 
or  duct ;  and  taking  this  as  the  essential  cha- 
racteristic, there  is  no  difficulty  in  perceiving 
that  the  glandular  system  in  the  human  body 
ought  to  be  restricted  to  the  following  parts: — 

Mucous  glands,  comprising,  a,  simple  mu- 
cous glands  or  follicles,  dispersed  over  the 
whole  extent  of  the  various  mucous  surfaces, 
either  insulated  or  collected  together,  as  the 
glandulae  Peyeri  seu  aggregatae.  b,  Compound 
mucous  glands,  (g.  agglutinate,)  formed  of  the 
preceding,  collected  into  masses,  and  slightly 
modified  in  their  structure,  comprising  the 
molar,  labial,  palatine,  and  buccal  glands,  the 
lachrymal  caruncle,  tonsils,  Cowper's  glands, 
prostate,  and  seminal  vesicles,  c,  Sebaceous 
glands,  consisting  of  those  of  the  skin,  the 
ceruminous  glands,  the  Meibomian  glands,  d, 
Conglomerate  glands,  (g.  conglomerate ;) 
these,  which  are  the  most  complex  of  the  glan- 
dular organs,  consisting  of  the  salivary  glands 
and  pancreas,  the  mammary  glands,  the  testicle, 
the  kidney,  and  the  liver. 

These  glands  may  be  classed  according  to 
their  functions  in  the  economy  as  follows: — 

I.  P'or  lubrication  and  protection  ;  a.  mu- 
cous glands  in  all  parts  of  the  body  ;  b.  seba- 
ceous glands  ;  c.  lachrymal  gland  ;  d.  lachry- 
mal caruncle. 

II.  Connected  with  digestion ;  a.  salivary 
gland  ;  b.  pancreas  ;  c.  liver. 

III.  Connected  with  generation ;  a.  testis  ; 
b.  prostate  ;  c.  seminal  vesicles  ;  d.  Cowper's 
glands;  e.  mammary  gland. 

IV.  For  excretion  ;  a.  kidney  ;  b.  liver. 

By  extending  the  principle  that  all  glands  are  in 
reality  nothing  but  processes  of  the  mucous  mem- 
brane ending  in  cul-de-sac,  the  lungs  have,  by 
some  writers,  been  included  amongst  the  glandular 
organs,  the  trachea,  it  is  said,  performing  the  office 
of  an  excretory  duct.  It  is  certain,  as  we  shall 
subsequently  show,  that  the  lungs  present,  both  in 
their  formation  and  functions,  a  close  approxima- 
tion to  the  true  glands. 

VOL.  II, 


The  particular  description  of  the  above 
organs  and  the  modifications  of  the  general 
glandular  structure  they  present,  will  be  found 
in  the  articles  Kidney,  Lachrymal  appara- 
tus, Mamma,  &c. 

Situation. — The  principal  glands  are  placed 
in  the  head  and  abdomen ;  in  the  extremities, 
with  the  exception  of  those  of  the  skin,  they 
are  totally  absent.  In  general  they  are  pro- 
tected from  external  injury  by  being  lodged 
deeply  in  the  cavities  of  the  body ;  but  to  this 
rule  there  are  several  important  exceptions,  as 
the  mammae,  testes,  parotid  glands,  &c. 

Organization. — In  the  whole  range  of  Ana- 
tomy, whether  Human  or  Comparative,  there 
are  probably  no  organs  which,  on  account  of 
the  complexity  of  their  structure,  the  number 
and  variety  of  forms  which  they  present,  and 
the  importance  of  their  functions  in  the  animal 
kingdom,  are  more  interesting  than  the  glands, 
or  the  structure  of  which,  until  within  a  very 
recent  period,  was  more  imperfectly  understood. 
Even  at  the  present  time  the  prevailing  ideas 
respecting  the  essential  characters  of  the  glan- 
dular organization  are  in  general  so  vague  and 
indefinite,  and  but  too  often  positively  errone- 
ous, that  I  feel  myself  called  upon  to  enter 
more  fully  into  the  investigation  of  this  subject, 
than  would  otherwise  be  necessary.  Much  of 
this  uncertainty  has  arisen  from  the  fact  that, 
whilst  the  views  of  the  immortal  Malpighi, 
founded  as  they  are  on  truly  philosophic 
grounds,  have  never  attracted  that  investigation 
to  which  they  are  so  justly  entitled,  the  theore- 
tical opinions  of  Ruysch,  being  received  with 
all  the  eclat  inspired  by  his  unrivalled  skill  in 
vascular  injections,  have  been  generally  adopted. 
It  is  true  that,  on  many  minor  points,  Malpighi 
was  in  error;  and  that  the  vagueness  of  his 
descriptions,  and  his  infelicitous  comparison  of 
the  ultimate  divisions  of  the  glands  with  clus- 
ters of  grapes  or  acini,*  greatly  assisted  in  pre- 
venting his  opinions  being  generally  admitted 
or  even  comprehended.  But  those  distin- 
guished anatomists  who  have,  by  their  recent 
inquiries,  at  length  decided  the  long-disputed 
theories  of  Malpighi  and  Ruysch,  have  proved 
that  in  all  essential  points  the  conclusions  of 
the  former  great  authority  are  founded  in  truth. 

Minute  structure. — The  investigation  into 
the  structure  of  the  glands,  when  conducted  in 
accordance  with  the  enlightened  principles  of 
philosophical  anatomy,  shows  that  the  laws 
which  regulate  their  formation  are  simple  and 
definite  ;  and  that,  although  Nature  has  dis- 
played here,  as  in  all  her  other  works,  immense 
fertility  in  modifying  the  forms  and  characters 
of  the  several  glands,  so  as  to  render  them  effi- 
cient to  the  performance  of  their  varied  offices, 
yet  in  no  single  instance  is  there  a  departure 
from  that  structure,  which  constitutes  the  type 
of  the  whole  glandular  system.    The  unifor- 

*  This  term,  so  much  employed  in  descriptions 
of  the  glands,  yet  so  indefinite  in  its  acepptation, 
has  caused  such  confusion  and  misconception,  that 
it  is  most  desirable  to  abolish  it  from  the  nomen- 
clature of  Anatomy.  In  the  descriptive  part  of  the 
present  article,  I  shall  therefore  scrupulously  avoid 
employing  this  expression. 

2  K 


482 


GLAND. 


mity  which,  with  the  aid  of  Comparative  Ana- 
tomy, has  been  so  satisfactorily  demonstrated 
in  the  development  of  the  nervous  and  osseous 
systems,  is  equally  evinced  in  the  glands  ;  for 
whatever  diversities  may  be  presented  in  their 
form  and  appearances — whatever  varieties  may 
be  remarked  in  the  internal  disposition  of  their 
component  parts,  as  in  contrasting  a  simple 
follicle  with  a  conglomerate  gland,  or  the  tubu- 
lar biliferous  organs  of  insects  with  the  appa- 
rently solid  liver  of  the  Mammalia;  whether,  in 
short,  they  appear  solid,  cellular,  or  tubular, 
every  glandular  organ  is  nothing  else  than  a 
modification  of  a  simple  closed  sac.  This  im- 
portant truth  is  distinctly  announced  by  Meckel 
in  the  following  passage.  "  The  most  simple 
mucous  glands,  which  are  only  simple  sacs, 
present  the  type  of  the  glandular  formation.  If 
we  picture  to  ourselves  this  sac  as  being  pro- 
longed and  ramified,  and  interlacing  its  branches 
between  those  of  the  bloodvessels,  we  shall  at 
length  arrive  at  the  most  compound  gland, 
without  there  ever  being  a  direct  communica- 
tion between  the  bloodvessels  and  the  excretory 
ducts."  *  We  have  here  briefly  but  clearly  ex- 
pressed the  great  principle,  in  obedience  to 
which  the  various  glands  are  developed ;  but 
that  which  Meckel  only  figuratively  expressed, 
has  since  been  realized  in  all  its  bearings  and 
intricate  details,  by  the  extensive  and  laborious 
researches  of  several  distinguished  anatomists, 
and  especially  by  Professor  Miiller  of  Berlin. 

As  it  would  be  in  vain  to  attempt  to  demon- 
strate the  essential  characters  of  the  glandular 
formation,  and  to  prove  the  uniformity  which 
pervades  the  whole  system,  by  selecting,  as  has 
been  generally  done,  the  most  intricate  organs  ; 
I  propose,  in  the  first  place,  to  describe  the 
most  simple  form  of  gland,  and,  seizing  this  as 
a  clue,  to  trace  its  gradual  development  through- 
out the  whole  series  of  glandular  organs,  so  as 
to  convey  a  general,  but,  it  is  hoped,  compre- 
hensive account  of  this  interesting  branch  of 
anatomy. 

With  this  object  in  view,  the  simple  follicles 
of  the  skin  and  mucous  membrane  may  be  ad- 
vantageously selected  ;  because  by  tracing  the 
successive  development  of  these  bodies,  the 
gradual  transformation  of  a  simple  sac  into  a 
tube,  a  ramified  canal,  and  even  a  conglome- 
rate gland,  may  be  very  distinctly  demonstrated. 
In  fishes,  whose  aquatic  mode  of  life  renders 
an  abundant  defensive  secretion  necessary,  the 
cutaneous  follicles  are  more  developed  than  in 
other  animals,  and  constitute  tubes  or  canals, 
which  being  carefully  examined  are  found  to 
end  in  ccecal  extremities.  A  similar  formation 
is  seen  in  the  bulbus  glandulosus  of  most  birds, 
where  the  mucous  crypts  are  prolonged  into 
short  tubuli  (fig.  209)  ;  whilst  in  the  Ostrich 
( Struthio  camelus )  the  follicles  present  an  ap- 
pearance of  cells.  (Fig.  209,  b).  In  some 
Amphibia,  Salamandra  maculuta  for  example, 
the  glands  of  the  external  integument  being 
very  much  developed,  it  is  seen  that  each  of 

*  Man.  d'An.  i.  p.  515.  Beclard  has  a  similar 
comparison  :  "  it  is  true  that  a  gland,  like  a  folli- 
cle, consists  of  a  canal  closed  at  the  extremity." 
Anat.  Gen.  p.  424. 


Fig.  209. 


a.  Conglomerate  folli- 
cular gland,  Struthio  rhea  ; 
c.  same,  Meleagris ;  d. 
same,  Anser  ;*  the  upper 
drawing  shows  the  cylin- 
drical follicles  in  a  young 
falcon. 


Fig.  210. 


those  bodies  is  com- 
posed of  a  small  flask- 
shaped  pouch  of  the 
skin,  which  at  one  ex- 
tremity becoming  en- 
larged into  a  base, 
there  terminates  in  a. 
blindsac ;  whilst  at  the 
other  end  being  con- 
tracted, it  opens  by  a 
short  neck  on  the  ex- 
ternal surface.  (See 
fig.  210*.)  A  micro- 
scopical view  of  the 
coecal  canals  in  the 
simpler  glands  is  ap- 
pended. (See$g.2ll.) 

Fig.  211. 


Flask-shaped  cutaneous  The  simple  sacs  and 
follicle  or  gland  magni-     tuDes  just  described  are 

Jied—\W.i  yery  often  couected  t0ge. 

ther,  giviug  rise  to  aggregate  or  compound  folli- 
cles, the  arrangement  and  degree  of  complexity 
of  which  are  very  various.  In  some  instances 
these  sacs  unite  so  as  to  form  a  gland  witha  single 
orifice  or  excretory  duct,  of  which  the  Meibo- 
mian glands  of  the  eye-lids  are  an  example  ;  or 
again,  the  aggregate  follicles  may  themselves  be 
joined  together  with  various  degrees  of  compli- 
cation, in  the  form  of  a  cluster,  from  which 
several  excretory  ducts  proceed,  as  in  the  cu- 
runcula  lachrymalis,  the  labial,  buccal,  and 
other  mucous  glands  of  the  mouth,  the  tonsils, 
&c.  In  all  these  instances  there  is  nothing  but 
an  evolution  of  the  original  sac,  so  that  in  the 
same  manner  as  this  is  formed  from  the  mucous 
membrane  or  skin,  are  the  tubes  and  canals 
prolonged  from  the  third  pouch,  by  which  con- 
trivance the  surface  subservient  to  secretion  is, 
within  a  given  space,  greatly  increased.  The 
conversion  of  a  sac  or  tube  into  a  granular  mass 
is  also  in  this  manner  rendered  very  apparent ; 
and  thus  it  is  easy  to  understand  how  a  rami- 
fied canal  may  produce  the  apparently  solid 

*  Home,  Lect.  on  Comp.  An.  ii.  tab.  46. 
t  Berres. 


GLAND. 


433 


granules  (the  so  much  talked  of  acini )  of  the 
liver  and  other  conglomerate  glands. 

Such,  then,  are  the  more  simple  forms  of  the 
glandular  organs ;  and  if  we  proceed  to  those 
which  are  more  complex,  no  difficulty  is  expe- 
rienced in  proving,  by  the  aid  of  comparative 
and  developmental  anatomy,  that  the  structure, 
although  it  becomes  more  and  more  developed, 
is  in  character  essentially  the  same.  The 
inquiries  of  the  anatomist  in  this  respect  are 
greatly  facilitated  by  the  existence  of  an  univer- 
sal law  connected  with  the  process  of  organiza- 
tion, in  accordance  with  which  it  happens  that, 
whenever  any  particular  gland  first  appears  in 
the  animal  series,  it  presents  invariably  the 
simplest  form  of  the  glandular  structure,  al- 
though this  same  gland  may  subsequently 
attain  in  the  higher  classes  the  most  intricate 
formation.  It  is  for  this  reason  the  salivary 
glands  are  so  simple  when  they  first  appear  in 
birds,  the  pancreas  in  fishes,  and  the  liver  in 
insects. 

Ample  confirmation  of  this  gradual  transition 
from  simple  to  compound,  which  is  in  fact 
only  another  instance  of  the  great  laws  which 
regulate  the  formation  of  the  whole  animal 
creation,  is  afforded  by  following  any  of  the 
more  intricate  glands  through  the  several  stages 
of  their  development.  Thus,  if  the  pancreas 
be  examined  in  its  rudimentary  state,  it  will  be 
perceived  that,  like  the  mucous  follicle,  it  is 
composed  either  of  a  fluid  sac  or  of  a  tube  more 
or  less  complicated.  In  the  class  Cephalopoda, 
the  individuals  of  which  are  so  remarkable  by 
the  complexity  of  their  internal  organization, 
the  pancreas  consists  either  of  a  simple  sac 
opening  into  the  intestine  near  the  gizzard,  (see 
fig.  219,  p,  fig.  220,/,  vol.  i.  p.  533),  or  of  a 
sprfal  canal,  (fig.  221,  /',  p.  535,)  the  secerning 
sifrface  being  increased  by  a  number  of  lamina3. 
In  most  fishes  there  are  numerous  fluid  appen- 
dages placed  near  the  pyloric  extremity  of  the 
stomach,  (  appendices  pyloric^,)  which  are  with 
propriety  regarded  as  constituting  a  rudimen- 
tary pancreas,  (fig.  212,)  and  which,  in  the  in- 


Fig.  212. 


Fig.  213. 


stance  of  the  Sturgeon  and  Swordfish  are  ag- 
gregated into  a  glandular  mass.*  (See  fig.  46, 
vol.  i.  p.  1 15.) 

The  liver  is  certainly  the  most  intricate  struc- 
ture of  all  the  glandular  organs  when  examined 
in  the  higher  animals  ;  and  yet,  if  we  descend 
to  the  lower  classes,  which  present,  as  it  were, 
a  natural  analysis  of  the  various  parts  of  the 
animal  machine,  the  texture  becomes  suffici- 
ently simple.  One  of  the  most  simple  forms 
of  this  organ  is  probably  furnished  in  the  lum- 
bricus  terrestris ;  at  least  I  have  seen  in  that 
animal,  in  a  few  instances,  a  beautiful  appear- 
ance of  coecal  tubuli  composing  the  yellowish 
substance  which  coats  the  intestine,  and  which 
is  thought  by  some  authorities  to  constitute  the 
liver.  In  many  insects,  Crustacea  and  other 
Articulata,  the  biliferous  organs  consist  of  fluid 
sacs  proceeding  from  the  stomach  or  intestine, 
and  often  assuming  the  appearance  of  tubes, 
but  always  closed  at  their  distal  extremities. 
In  some  instances  these  tubuli  are  very  simple, 
(see  fig.  37,  d,  vol.  i.  p.  Ill,)  but  in  other 
cases  they  are  more  complicated,  and  present  a 
ramified  arrangement ;  and  in  this  manner  the 
structure  evidently  approaches  that  of  the  most 
compound  or  conglomerate  glands.  The  liver 
of  the  Lobster  presents  an  excellent  illustration 
of  the  ccecal  tubuli  which  constitute  the  secre- 
ting structure  of  so  many  species  of  glands. 

By  cutting  out  a  por- 
tion of  this  organ,  and 
slightly  unravelling  the 
tubes  by  moving  the 
section  in  water,  the 
canals  ending  in  cul- 
de-sac  are  beautifully 
seen,  and  if  slightly 
magnified,  it  is  found 
that  they  closely  re- 
semble the  pyloric  ap- 
pendages of  fishes.  The 


*  Haller  remarks  that,  in  the  Skate  and  Shark, 
the  pancreas  is  similar  to  that  of  higher  animals 

2  K  2 


484 


GLAND. 


adjoining  figure  (Jig.  214)  conveys  a  very 
accurate  representation  of  this  structure  as  it 
exists  in  the  biliary  organs  of  the  astacus 
Jluviatilis,  the  digital  tubuli  (c)  being  depicted 
as  they  appear  when  partly  unravelled. 

In  another  of  the  Crustaceans,  pagurus  stria- 
tum (Jig.  215),  the  same  kind  of  structure  is 

Fig.  215. 


observed,  constituting  a  very  complex  liver. 
In  the  squilla  mantis  that  organ  is  so  remark- 
ably intricate  that  Cuvier  supposed  it  formed 
an  exception  when  compared  with  the  other 
genera  of  the  Crustacea,  which,  as  we  have 
seen  in  the  instances  above,  possess  biliary 
organs  composed  of  blind  tubes,  by  being  ta- 
bulated and  solid  like  a  conglomerate  gland* 
It  has,  however,  been  ascertained  that  the 
lobules  are  excavated  in  their  whole  extent, 
and  communicate  by  openings  with  the  intes- 
tine, which  runs  through  their  spongy  mass, 
so  that  the  secreting  surface  is  wonderfully 
increased  in  extent  f 

That  the  liver  consists  of  a  blind  pouch, 
originating  from  the  intestinal  canal  and  be- 
coming more  and  more  complicated,  is  further 
shown  in  many  of  the  Mollusca,  in  which  the 
excretory  ducts  are  so  large  that  they  appear 
like  branches  of  the  intestine,  and  thus  present 
a  structure  which  is  somewhat  analogous  to 

*  Lemons  d'An.  Comp.  t.4.  p.  152.  It  is  proper 
to  observe  that  Cuvier,  in  thus  alluding  to  a  solid 
conglomerate  gland,  appears  to  have  fallen  into 
the  common  error  respecting  the  nature  of  the 
minute  granules,  or  acini  as  they  are  called. 

t  M'uller  de  Gland.  Secernent.  Struct,  p.  70, 
$5. 


those  curious  ccecal  diverticula  observed  in 
certain  of  the  Annelida,  well  seen  in  the 
aphrudita  acuteata,  and  which  are  by  some 
anatomists  regarded  as  forming  a  rudimentary 
liver. 

The  evolution  of  the  liver  in  the  embryo 
affords  an  additional  proof  of  the  disposition 
of  the  secreting  surface  or  membrane  in  the 
interior  of  the  compound  glands.  In  one  of 
the  Gasteropods  (  Limnaus  stagnalis )  the  liver 
is  first  produced  as  a  pellucid  sac  from  the 
intestine.  In  an  amphibious  animal  (buj'o 
cumpanisonus )  a  prolongation  in  the  form  of 
a  sac  is  seen  in  the  intestinal  membrane,  which 
constitutes  the  first  appearance  of  the  liver;  as 
the  development  proceeds,  the  hepatic  duct  is 
formed,  and  becoming  ramified,  produces  at 
length  a  number  of  branching  tubes,  which 
present  a  granulated  form.  The  evolution  of 
the  liver  in  the  green  lizard  (lacerta  viridh ) 
is  very  similar,  the  organ  first  appearing  under 
the  form  of  a  hollow  sac  proceeding  from  and 
communicating  with  the  cavity  of  the  intestine, 
and  subsequently  having  branches  of  ramified 
tubes  added.* 

If  from  the  investigation  of  these  more  simple 
forms,  which  might  be  multiplied  almost  ud  in- 
finitum, we  proceed  to  the  conglomerate  glands 
of  Mammalia,  it  will  be  observed  that,  al- 
though the  component  parts  of  these  highly 
organized  bodies  are  so  closely  packed  together 
as  to  present  a  solid  and  granular  appearance, 
yet  by  a  careful  inspection  it  may  be  satisfac- 
torily determined  that  the  true  secreting  struc- 
ture consists  of  tubuli  with  ccecal  ends.  For 
this  purpose  the  testicle  may  be  advantageously 
selected  :  if  this  organ  without  any  previous 
injection  be  divided,  the  section  at  first  sight 
seems  to  consist  of  a  great  number  of  small 
roundish  bodies  or  granules;  but  if,  as  occa- 
sionally happens,  the  tubes  are  distended  with 
semen  at  the  time  of  death,  by  a  more  cautious 
examination  it  is  immediately  apparent  that 
these  little  bodies  are  composed  of  a  very  fine 
tube  coiled  up  or  convoluted.  By  injecting 
the  tubuli  seminiferi  with  mercury,  the  formation 
of  the  little  grains  is  rendered  more  evident; 
but  the  most  successful  mode  of  displaying 
the  whole  internal  formation  of  the  testis  is  by 
filling  the  tubuli  with  a  coloured  size  injec- 
tion.f 

1 1  was  remarked  by  Ferrein  J  that  the  kid- 
ney is  a  tubular  organ,  and  the  extensive  re- 
searches of  Miiller  as  well  as  those  of  Huschke 
have  proved  that  the  secreting  or  cortical  part 
is  made  up  of  an  immense  number  of  serpen- 
tine tubes  of  an  equal  diameter  throughout, 
ending  in  blind  sacs,  and  becoming  continuous 
with  the  straight  canals  placed  in  the  cones  of  the 
organ.  This  structure  is  seen  in  Jig.  216,  where  a 
magnified  view  of  the  cortical  ducts  of  Ferrein, 
the  secerning  apparatus,  and  the  straight  excre- 
tory tubes  is  given  as  the  parts  exist  in  the 
sciurus.  This  structure  offers  a  close  resem- 
blance to  the  tubuliform  liver  of  some  insects. 


*  Miiller  1.  c.  tab.  x.  Jig.  13. 

t  Sir  A.  Cooper  on  Testicle. 

%  Mem.  de  l'Acad.  Roy.  des  Sc.  1749,  p.  489. 


GLAND. 


485 


(See  the  biliary  organs  of 
Meloloutha  Vulgaris,  Jig.  38, 
vol.  i.  p.  111.) 

In  the  liver  of  Mammalia 
and  Man,  both  in  the  embryo 
and  after  birth,  it  is  much 
more  difficult  to  demonstrate 
the  ultimate  tubes  with  their 
coecal  extremities;  indeed  the 
existence  of  such  canals  is  ra- 
ther deduced  from  the  ana- 
logy of  the  liver  in  the  lower 
animals  than  from  actual  ob- 
servation. M  idler  states  that 
the  blind  free  extremities  of 
the  biliary  ducts  are  visible 
on  the  surface  of  the  liver 
with  the  microscope  in  the 
embryo  of  Mammalia;  but 
that  owing  to  their  compact 
arrangement  they  are  less  dis- 
tinct than  in  birds,  so  that 
their  internal  connexions  can- 
not be  perceived.*  In  a  few 
Mammalia,  however,  as  the 
squirrel,  ( sciurusvu/garis,)  he 
observed  with  the  microscope 
the  blind  cylindrical  extremi- 
ties of  the  biliary  ducts  on 
the  surface  of  the  liver,  pre- 
senting a  branching  and  foliaceous  appearance. 
( Fig.  217.)  The  exact  mode  of  termination  of 

Fia.  217. 


Fig.  216. 


the  biliary  tubuli  was  still  more  distinctly  seen 
in  a  portion  of  liver  considerably  magnified, 
taken  from  an  embryo  of  the  quail,  ( 'Tetruo 
coturnix,)  about  one  inch  long  (Jig.  2X8). 

From  the  published 


Fie.  218. 


account  of  Mr. 
Kiernan's  valuable 
observations  on  the 
minute  structure  of 
the  liver,  it  does 
not  appear  that  the 
actual  terminations 
of  the  biliary  tubes 


in  blind  extremities  were  perceived,  although 
that  such  is  their  disposition  is  rendered  very 
probable  from  what  was  seen  with  the  mi- 
croscope, and  especially  because  it  was  found 
that  much  greater  difficulty  was  experi- 
enced in  injecting  these  tubes  than  the 
bloodvessels,  on  account,  as  it  was  sur- 
mised, of  the  bile  contained  within  them 
having  no  exit.* 

Lastly,  in  tracing  the  minute  texture 
of  these  complex  glands  of  the  Mam- 
malia, it  is  necessary  to  call  the  attention 
of  the  reader  to  a  circumstance  which  of 
all  others  has  been  the  most  fertile  source 
of  error,  so  much  so  indeed  as  to  have 
misled  the  great  majority  of  anatomists. 
It  is  this  :  in  many  glands  small  rounded 
or  berry-shaped  corpuscles  seem  to  be 
appended  to  the  commencement  of  the 
secreting  tubes,  so  that  a  deceptive  ap- 
pearance is  produced,  as  if  cells  or  little 
bags  were  placed  between  the  terminal 
bloodvessels  and  the  small  excretory 
ducts.  This  appearance  of  cells  or  even 
of  solid  rounded  corpuscles  is  depen- 
dent on  two  causes :  in  some  glands  the  se- 
creting canals  are  so  coiled  up  that,  as  is  seen 
in  the  human  testis,  when  a  section  is  made  in 
the  uninjected  state  an  apparently  granular  tex- 
ture is  presented,  (Jig.  219;)  but  a  second 
influential  circumstance  is  that  in  many  in- 
stances each  of  the  secreting  tubes  swells  out 
at  its  ccecal  end  into  a  slightly  enlarged  cul- 
de-sac  ( pedunculated  tubes),  so  that  when  they 
are  viewed  in  an  aggregate  form,  the  semblance 
of  roundish-shaped  granules  is  seen,  (fig. 
220.)  As  these  and  all  other  varieties  which 
are  presented  in  the  glandular  formation  are 


*  L.  c.  p.  80,  $21,  22. 


*  Phil.  Trans.  1833,  p.  741. 


486 


GLAND. 


It  is,  however,  very  remarkable  that  whilst 
those  glands  which  arise  from  the  alimentary 
canal  present  an  immense  variety  in  the  ar- 
rangement of  their  secreting  texture,  the  essen- 
tial glands  of  the  genito-urinary  apparatus,  the 
kidney  and  the  testicle,  have  a  most  uniform 
structure,  consisting  of  serpentine  tubes  of  the 
same  diameter  throughout  their  whole  extent. 

The  details  into  which  I  have  thought  it  re- 
quisite to  enter  prove  that  the  true  secreting 
structure  consists  in  every  gland  of  nothing 
else  than  a  vascular  membrane,  on  the  surface 
of  which  the  glandular  fluid  is  poured  out;  and 
consequently  that  in  those  complex  organs,  as 
the  liver  or  kidney,  in  which  the  vascular  se- 


Fig.  220. 


Peripheral  ramification  of  the  parotid  du  -t,  with  some  of  the  vesicular  terminations, 
magnified  —  110.* 


Fig.  219. 


considered  in  the 
several  articles 
on  the  individual 
glands,  it  is  only 
necessary  to  state 
in  this  place  that 
what  are  called 
indifferently  lo- 
bules, glandular 
grains,  vesicles, 
acini,  &c.  are  in 
every  instance 
composed  simply 
of  the  secreting 


canals  variously  disposed  and  arranged 


creting  membrane  is,  for  the  sake  of  conveni- 
ence, disposed  in  the  form  of  extensively  rami- 
fied tubes,  it  is  most  important  to  recollect  that 
the  glandular  fluid  is  poured  not  only  into  the 
ccecal  extremity  or  commencement  of  each 
tube,  as  is  the  commonly  received  opinion,  but 
ak>ng  the  whole  extent  of  the  tube.  For  the 
establishment  of  this  fact,  certainly  the  most 
important  in  the  history  of  the  glands,  we  are 
principally  indebted  to  Professor  Muller. 

Excretory  duct. — Although  the  essential  seat 
of  the  glandular  function  is  now  ascertained, 
some  difficulty  exists  in  determining  the  actual 
extent  of  the  secreting  surface  in  the  various 
organs ;  or  in  other  words,  at  what  precise 
point  the  mucous  canals  ceasing  to  secrete, 
become  mere  excretory  passages.^  An  attempt 
to  decide  this  point  is,  however,  necessary, 
because  until  this  time  the  majority  of  anato- 

*  Berres,  1.  c.  pt.  5,  tab.  ix.  fig.  2. 

t  I  allude  here  of  course  to  the  peculiar  secre- 
tions, as  the  bile,  urine,  milk,  &c.  and  not  to  the 
secretion  of  mucus,  which  we  know  is  poured  out 
along  the  whole  extent  of  the  excretory  ducts. 


mists  have  signified  by  the  term  excretory  duct, 
not  only  the  canals  which  simply  bear  away 
the  secreted  fluid,  but  likewise  those  tubes 
which  constitute  the  true  secreting  apparatus, 
and  which,  it  is  evident,  are  at  the  same  time 
both  secreting  and  excreting  canals,  as  they  not 
only  secrete,  but  likewise  carry  to  the  larger 
and  non-secreting  ducts  the  fluids  poured  out 
by  their  parietes. 

In  the  simple  sacculi  or  follicles,  it  is  evi- 
dent that  the  secreting  structure  is  co-equal 
with  the  extent  of  the  bag  itself,  so  that  the 
little  orifice  becomes  the  excretory  duct;  in  the 
tonsils,  prostate,  &c.  there  are  several  such 
orifices  or  ducts.  But  at  what  point  does 
secretion  cease  in  the  compound  glands  ?  Mr. 
Kiernan  states,*  that  in  the  liver  the  secreting 
portion  of  the  organ  is  confined  to  what  he 
calls  the  lobular  biliary  plexuses,  or  to  those 
tubes  which  are  placed  within  the  lobules ;  so 
that  here  the  excretory  apparatus  is  very  com- 
plex, consisting  of  the  interlobular  tubes,  those 

*  Phil.  Trans.  1833,  p.  741. 


GLAND. 


487 


of  Glisson's  capsules,  and,  lastly,  of  those 
which  quit  the  organ.  The  limitation  thus 
established,  and  which  I  have  no  doubt  is 
strictly  correct,  may  be  applied  to  all  those 
glands,  such  as  the  salivary,  mammary  organs, 
&c,  which,  like  the  liver,  possess  distinct 
lobules.  In  the  kidney  the  true  secreting 
structure  is  probably  restricted  to  the  serpen- 
tine tubes  contained  in  the  cortical  texture, 
(canales  corticales,  or  ducts  of  Ferrein,)  the 
straight  canals  (tub.  Belliniani)  constituting 
the  cones,  which  bodies,  in  a  minute  injection 
of  the  bloodvessels,  are  nearly  colourless, 
being  merely  for  excretion.*  The  testis,  with 
its  appendix  the  epididymis,  presents  an  in- 
tricate arrangement;  it  is  probable,  however, 
that  the  principal  secreting  part  consists  of  the 
seminal  tubes  which  form  the  lobules,  and  that 
the  vasa  recta  and  efferentia  are  merely  ex- 
cretory in  their  office;  in  the  upper  part  of  the 
epididymis  a  second  secreting  structure  is  met 
with,  constituting  the  coni  vasculosi,  whilst 
the  lower  part  containing  the  convolutions  of 
the  vas  deferens  is  of  the  excretory  character. 

It  is  proper  to  observe  that  the  process  of 
secretion  is  incessantly  going  on  ;  but  with  the 
exceptions  of  the  mucous,  sebaceous,  and  a 
few  other  glands,  the  fluids  produced  are 
destined  to  be  poured  out  only  at  stated  in- 
tervals ;  it  is,  therefore,  evident  that  some  con- 
trivance is  required,  by  which  the  several  secre- 
tions may  be  retained,  till  the  moment  arrives 
when  it  is  necessary  they  should  be  discharged. 
The  liver  may  be  selected  to  illustrate  this 
principle  :  one  of  the  most  essential  functions 
of  that  organ  being  the  decarbonization  of 
venous  blood,  its  constant  action  is  no  less 
indispensable,  indeed  considering  the  whole 
animal  series,  is  even  more  indispensable  than 
that  of  the  lungs  themselves ;  and  yet  the  pro- 
duct of  that  action,  the  bile,  is  only  designed 
to  be  poured  into  the  duodenum  during  the 
process  of  digestion.  In  order  to  obviate  the 
irritation  of  the  bowels  that  would  result  from 
the  incessant  discharge  of  the  bile,  and  at  the 
same  time  to  economise  that  fluid,  the  gall- 
bladder is  provided,  which,  receiving  the  se- 
creted fluid  in  the  intervals  of  digestion,  fulfils 
all  the  conditions  required.  The  absence  of 
the  gall-bladder  in  several  classes  of  animals 
can  scarcely  be  admitted  as  being  incompatible 
with  this  explanation ;  for  the  majority  of 
these  instances  of  deficiency  occur  in  non- 
ruminant  vegetable  feeders,  in  several  genera 
of  the  Pachydermata  and  Rodentia  for  example, 
in  which  it  is  evident  that  as  the  process  of 
digestion  must  occupy  a  considerable  period, 
a  prolonged  flow  of  bile  is  requisite,  and  a 
special  reservoir  is  less  necessary ;  in  addition  to 

*  It  is  stated  by  Muller  that  all  his  researches 
induce  him  to  conclude  that  the  serpentine  tubuli 
of  the  cortical  part  constitute  the  true  secreting 
texture;  an  opinion  which  is  corroborated  by  a 
very  curious  preparation  contained  in  the  museum 
of  the  Webb -Street  School  of  Anatomy,  in  which 
a  sac  has  been  formed  on  the  outer  surface  of  the 
kidney,  containing  a  number  of  small  calculi,  and 
having  no  connexion  whatever  either  with  the 
straight  tubes  or  with  the  infundibula. 


which  it  is  known  that  in  some  of  these  cases, 
as  in  the  horse  and  elephant,  the  principal 
trunk  of  the  biliary  ducts  is  very  large,  and 
may  in  some  degree  supply  the  place  of  a  gall- 
bladder* 

The  urinary  bladder  is  a  provision  rather 
of  convenience  than  of  necessity,  enabling  the 
animals  that  possess  it  to  retain  the  urine  as  it 
flows  from  the  ureters,  until  a  considerable 
accumulation  takes  place.  These  are  the  only 
instances  in  the  human  body  of  a  distinct  re- 
servoir being  provided  ;f  but  every  gland,  by 
retaining  its  secretion  in  the  excretory  ducts, 
has  a  power  of  emitting  the  fluid,  under  certain 
circumstances,  in  larger  quantities  than  usual, 
as  in  the  case  of  the  salivary  and  lachrymal 
glands;  a  similar  accumulation  must  take  place 
in  the  seminal  tubes  and  prostatic  ducts,  and 
especially  in  the  lactiferous  tubes  and  their 
terminal  sinuses.  In  animals  the  examples  of 
distinct  reservoirs  are  too  numerous  to  be  here 
enumerated. 

Structure  of  the  secreting  canals  and  excre- 
tory ducts. — It  is  now  certain  that  all  these 
tubes  are  composed  essentially  of  a  prolonga- 
tion of  the  mucous  membrane.  The  former, 
according  to  Muller,  consist  only  of  a  single 
coat,  but  it  must  be  presumed  that  they  pos- 
sess in  addition  a  tunic,  having,  independently 
of  elasticity,  a  power  of  contraction  by  whicli 
their  contents  are  propelled  often  in  a  direction 
opposed  to  gravity,  and  in  obedience  to  the 
application  of  a  mechanical  stimulus  to  the 
surface  on  which  the  ducts  terminate.  In  the 
excretory  ducts  the  internal  membrane  is  sur- 
rounded by  a  fibrous  structure,  which  is  very 
apparent  in  some  of  the  larger  canals,  and 
probably  exists  in  all.  The  fibres  of  this  coat 
are  of  a  greyish  white  or  brownish  colour,  and 
are  often  so  fine  and  compact  that  they  are 
distinguished  with  great  difficulty.  The  real 
character  of  this  structure  is  not  known  ;  in 
appearance  there  is  little  or  no  resemblance  to 
proper  muscle;  the  action,  however,  of  the 
excretory  canal  seems  to  require  a  contractile 
power;  and  Meckel  states  that  he  has  dis- 
tinctly perceived  circular  fibres  in  the  vas 
deferens,  which  tube  is  said  to  be  distinctly 
muscular  in  the  bull. 

Bloodvessels. — If  it  be  recollected  that  the 
arteries  carry  to  the  glands  the  materials  of 
their  various  secretions,  and  if  the  large  quan- 
tity of  fluid  formed  by  those  viscera  be  called 
to  mind,  we  shall  not  be  surprised  to  find  that 
with  a  few  exceptions,  such  as  the  lungs  and 
the  brain,  there  are  no  organs  so  abundantly 
supplied  with  arterial  blood.  This  supply  is 
in  proportion  to  the  activity  of  secretion,  rather 
than  to  the  size  of  the  gland  ;  thus  the  kidneys, 

*  Carus,  Traite  Elem.  d'An.  Comp.  ii.  p.  269. 
It  may  be  proper  to  state  that  the  Otter,  according 
to  Daubenton,  possesses  the  above  dilatation  of  the 
duct  in  conjunction  with  a  gall-bladder. 

f  Some  anatomists  conceive  that  the  vesiculas 
seminales  are  merely  receptacles  of  the  semen  ; 
but  this  opinion  has  been  to  a  great  extent  aban- 
doned in  England  since  the  observations  of  Hunter. 
See  the  works  of  Hunter,  edit,  by  Palmer,  vol.  iv. 
p.  20.    Note,  p.  26. 


488 


GLAND. 


furnishing  about  four  pints  of  urine  daily, 
receive,  in  proportion  to  their  bulk,  more  blood 
than  the  pancreas,  where  the  secerning  process 
is  less  active.  That  this  is  the  principle  which 
regulates  the  supply  of  blood  is  also  evidenced 
in  the  vessels  of  the  mammas,  which  receive  a 
more  ample  supply  of  blood  during  lactation 
than  at  other  periods. 

The  sanguiferous  vessels,  like  the  secreting 
canals,  present  many  varieties  in  their  dis- 
position in  the  several  glands,  the  varieties  of 
form  in  each  class  being,  however,  definite  in 
their  character,  and  doubtless  having  a  re- 
ference to  the  different  kinds  of  fluids  which 
are  required  to  be  separated  from  the  circu- 
lating blood.  Those  organs  which  are  pro- 
vided with  a  distinct  envelope,  as  the  testicle, 
the  kidney,  and  liver,  usually  possess  but  one 
artery,  which  enters  at  the  same  fissure  as  the 
excretory  canal ;  other  glands,  presenting  a  more 
distinctly  lobulated  texture  and  having  no 
proper  capsule,  the  tonsil,  pancreas,  and  mam- 
ma for  instance,  receive  an  indefinite  number 
of  arteries,  which  enter  irregularly  on  all  parts 
of  the  surface ;  lastly,  in  the  most  simple  form, 
as  the  mucous  crypts,  the  secreting  vessels  con- 
stitute a  delicate  plexus  on  the  surface  of  the 
little  bag. 

In  all  those  instances  where  the  gland  is 
large  enough  to  receive  one  or  more  arterial 
trunks,  it  is  found  that  the  vessel  having 
entered  begins  to  divide  into  smaller  branches, 
which  penetrate  between  the  masses  of  the 
gland,  and  these  becoming  smaller  and  smaller 
at  length  furnish  an  intricate  plexus,  the 
branches  of  which,  as  in  the  case  of  the  simple 
bag  or  follicle,  ramify  on  the  surface  of  the 
blind  secreting  canals. 

It  is  only  necessary  to  observe  with  respect 
to  the  veins,  that  when  compared  with  their 
arteries,  they  are  smaller  than  elsewhere  ;  and 
also  that  in  common  with  the  veins  of  the 
splanchnic  cavities,  they  are  devoid  of  valves, 
so  that  in  the  kidney,  liver,  &c.  they  may  be 
beautifully  displayed  by  the  aid  of  a  suc- 
cessful injection,  even  to  their  ultimate  rami- 
fications. 

Arrangement  of  the  minute  bloodvessels. — 
In  considering  the  intimate  texture  of  the 
glands,  it  is  essential  to  state  the  manner  in 
which  the  last  divisions  of  the  sanguiferous 
vessels  are  disposed.  By  the  aid  of  minute 
injection  these  vessels  may  be  demonstrated, 
though  with  difficulty,  as  far  as  their  termina- 
tion ;  and  they  may  also  be  observed  in  a  few 
instances  during  life  and  whilst  carrying  on  the 
circulation. 

An  opinion  to  which  we  shall  subsequently 
recur  has  been  entertained  by  many  anatomists, 
that  the  little  arteries  are  either  directly  con- 
tinuous with  the  excretory  ducts,  or,  as  we 
should  rather  call  them,  the  secreting  canals,  or, 
at  all  events,  that  some  kind  of  direct  commu- 
nication exists  between  the  terminal  arteries 
and  the  secreting  canals.  The  most  cautious 
and  apparently  successful  researches,  however, 
do  not  corroborate  this  opinion,  but,  on  the 
contrary,  show  that  no  direct  communication 
of  any  kind  exists.   In  the  lungs,  which  organs 


are  formed  and  developed  in  exact  accordance 
with  the  glandular  structure,  the  ultimate  divi- 
sions of  the  pulmonary  artery,  after  freely 
ramifying  over  the  surface  of  the  air-cells,  are 
known  to  terminate  by  direct  continuity  in  the 
radicles  of  the  pulmonary  veins.  Now,  that 
which  is  demonstrated  in  the  lungs  equally 
applies  in  the  case  of  the  glands.  In  the 
simple  lacunas  of  the  mucous  membrane  the 
arteries  are  disposed  over  the  surface  of  the 
pouch,  but  they  end  in  the  returning  veins 
without  opening  on  the  secreting  surface. 
Miiller  states  that  on  examining  with  a  suffi- 
cient power  the  larva  of  the  triton  palustris, 
he  observed  streams  of  blood,  traversed  by 
single  globules,  running  between  the  elongated 
secreting  canals  of  the  liver,  and,  further,  that 
the  last  arteries  pass  immediately  by  a  reticu- 
late anastomosis  into  the  small  hepatic  veins. 
This  disposition  is  seen  in  the  adjoining  figure, 
which  represents  the  circuit  of  the  blood  in  the 
larva  of  the  triton  fifteen  lines  in  length. 


Fig.  221. 


a,  vena  cava  ;  b,  vena  portarum  ;  c,  minute  cur- 
reuts  of  blood  in  the  gall-bladder.  ^ 


GLAND. 


489 


Miiller  expressly  says,  that  in  no  organ  are  the 
free  extremities  of  the  bloodvessels  seen,  but 
that  the  arteries  always  pass  by  a  reticulate 
anastomosis  into  the  veins ;  that  the  blood  cir- 
culates between  the  secreting  canals  of  the 
liver,  and  at  length  on  their  surface,  so  as,  as  it 
were,  to  soak  their  coats  with  blood,  but  it  does 
not  pass  into  the  canals  themselves;  or,  in 
other  words,  that  the  sanguiferous  vessels  are 
not  continuous  with  the  biliary  tubes.* 

The  important  investigations  of  Kiernan 
respecting  the  minute  anatomy  of  the  liver, 
have  shewn  that  the  vena  portee  having  divided 
so  as  to  constitute  an  intricate  plexus  in  each 
lobule  of  the  organ,  and  having  ramified  on 
the  secreting  canals,  terminates  in  the  hepatic 
vein.f  In  the  section  on  the  development 
further  evidence  is  furnished  in  corroboration 
of  these  observations. 

In  all  these  instances,  then,  it  is  proved  that 
there  is  no  continuity  between  the  arteries  and 
the  secreting  tubes;  and  as  the  smallest  secreting 
canals  are  always  considerably  larger  than  the 
smallest  bloodvessels,  the  proportion  varying 
in  different  glands,  it  may  be  assumed  that  in 
the  whole  glandular  system,  the  arteries,  having 
divided  to  a  great  degree  of  minuteness,  and 
having  ramified  freely  on  the  surface  of  the 
secreting  canals,  terminate  directly  in  the  re- 
turning veins.  , 

Although  in  former  times  such  a  disposition 
of  the  bloodvessels  as  that  now  described 
would  have  been  regarded  as  incompatible 
with  the  process  of  secretion,  yet  since  the 
interesting  researches  of  Dutrochet  on  Endos- 
mose  and  Exosmose,J  there  is  no  difficulty  in 
understanding  that  fluids  may  readily  pass 
from  the  interior  of  the  arteries  into  the  se- 
creting canals  without  there  being  any  direct 
communication  between  these  two  orders  of 
tubes.  Not  only  may  this  passage  take  place, 
but  even  it  is  rendered  probable  by  the  experi- 
ments of  Magendie§  that  the  bibulous  matter 
constituting  the  glandular  texture,  and  present- 
ing, as  we  have  found,  so  many  varieties  in  its 
physical  characters,  may  separate  fluids,  varying, 
according  to  the  gland  employed,  from  the 
diversified  substances  mechanically  mixed  toge- 
ther and  suspended  in  the  blood. 

Lymphatic  vessels. — Notwithstanding  these 
are  readily  traced  in  the  larger  glands,  their 
disposition,  and  especially  their  origin,  are  not 
known ;  a  connexion,  however,  has  been  rather 
generally  admitted  in  certain  glands  between 

•  De  Gland.  Struct.,  p.  74,  §  12.  Phys.  des 
Menscben,  1  Band,  p.  441. 

t  Phil.  Tran.  1833,  p.  745.  Mr.  Kiernan  infers 
that  the  hepatic  artery  terminates,  not  as  is  usually 
supposed  in  the  vena  hepatica,  but  in  the  vena 
porta?.  Miiller,  however,  thinks  it  is  not  probable 
that  this  is  the  true  disposition,  because  the  prepa- 
rations of  Leiberkuhn  show  that  the  capillary 
branches  of  the  venae  hepaticae  can  be  as  readily 
injected  from  the  hepatic  artery  as  from  the  hepatic 
vein.  Notwithstanding  these  objections,  analogy 
would  induce  us  to  suppose  that  Mr.  Kiernan  is 
correct  in  his  supposition. 

|  Nouv.  Recher.  sur  l'Endos.  et  l'Exosmose, 
1828. 

§  Lect.  on  the  Physical  Conditions  of  the  Tissues, 
Lancet,  1834-35. 


their  ducts  and  the  lymphatics.  In  one  instance 
Cruikshank  filled  the  absorbents  of  the  mamma 
from  the  lactiferous  ducts ;  and  both  Walter 
and  Kiernan  contend  that  the  absorbents  of  the 
liver  may  be  injected  from  the  biliary  ducts. 
Miiller,  on  the  contrary,  denies  this  commu- 
nication, and  states  that  the  lymphatics  are 
much  larger  than  the  smallest  secreting  canals. 
He  also  contends  as  to  the  results  of  injections, 
that  the  arguments  drawn  from  them  have  no 
greater  weight  than  all  others  derived  from  the 
fortuitous  passage  by  rupture  of  fluids  from 
one  into  a  different  order  of  vessels. 

Nerves. —  In  proportion  to  their  size  the 
glands,  like  the  other  organs  of  the  vegetative 
functions,  receive  very  small  nerves,  which  are, 
with  some  few  exceptions,  derived  from  the 
system  of  the  great  sympathetic.  The  nervous 
fibrils  surround  and  accompany  the  branches 
of  the  arteries,  till,  in  the  interior  of  the  gland, 
they  become  so  minute  that  it  appears  impossi- 
ble to  detect  their  exact  termination.  Miiller 
states  that  they  never  separate  from  the  blood- 
vessels, and,  consequently,  that  they  do  not 
supply  the  proper  glandular  substance.  But  in 
such  a  case  as  this  the  evidence  afforded  by 
microscopical  inspection  alone  should  be  re- 
ceived with  great  reserve,  especially  when  it  is 
recollected  that  in  opposition  to  the  doubtful 
information  thus  acquired  must  be  placed  the 
unquestioned  fact  that  the  mind  is  capable  of 
influencing  the  contraction  of  the  secreting  and 
excreting  tubes,  as  is  instanced  in  the  flow  of 
the  saliva,  of  the  tears,  and  of  the  semen  under 
certain  mental  impulses.  But  perhaps  a  still 
more  striking  illustration  of  the  control  of  the 
nervous  system  is  afforded  by  the  discharge  of 
several  glandular  fluids  resulting  from  impres- 
sions acting  on  comparatively  remote  but 
associated  surfaces — the  pouring  forth  of  the 
saliva  for  example,  in  consequence  of  the  con- 
tact of  various  substances  with  the  tongue ;  of 
the  bile  and  pancreatic  juice  from  the  applica- 
tion of  food  to  the  surface  of  the  duodenum ; 
of  the  semen  from  the  stimulation  of  the  glans 
penis.  In  all  these  and  similar  instances  it 
must  be  presumed  from  analogy  that  the  effect 
of  the  physical  impression  is  conveyed  through 
the  only  known  media  of  conduction,  the 
nerves.*  The  facts  here  adduced  respecting 
the  influence  of  the  nerves  merely  relate  to  the 
contraction  of  the  secreting  and  excreting 
canals ;  how  far  the  nervous  energy  is  essential 
to  the  process  of  glandular  secretion  itself  be- 
longs to  another  division  of  the  subject.  (See 
Secretion.) 

Interstitial  cellular  tissue. — A  considerable 
portion  of  every  gland  is  made  up  of  the  con- 
necting cellular  membrane,  which,  as  in  all  other 
organs,  enters  the  interior,  where  it  fills  up  all 
the  minute  fissures  and  angles  that  intervene 
between  the  tubes  and  lobules,  and  at  length, 
penetrating  between  the  most  minute  of  the 
secreting  canals,  it  constitutes  a  nidus  for  the 
lodgement  of  the  constituent  parts. 

The  investing  membrane  is  in  many  instances 

*  I  have  in  another  place  entered  more  fully 
upon  this  question  :  Obs.  on  the  Struct,  and  Funct. 
of  the  Spinal  Cord,  p.  136,  ct  scq. 


490 


GLAND. 


simply  formed  by  the  condensation  of  the  con- 
necting cellular  tissue,  but  in  the  larger  glands 
a  proper  fibrous  capsule  is  provided,  which 
adheres  more  or  less  intimately  to  the  proper 
glandular  texture. 

General  conclusions  respecting  the  minute 
structure  of  glands. 

1.  That  throughout  the  whole  range  of  the 
animal  kingdom  and  in  every  species  of  gland 
there  is  one  uniform  type,  from  which  the 
glandular  formation  in  no  instance  deviates. 

2.  That  every  gland  consists  of  a  membrane 
derived  either  from  the  skin  or  mucous  mem- 
brane. 

3.  That  this  membrane  is  disposed  either  in 
the  form  of  a  pouch  or  of  a  tube  more  or  less 
ramified,  and  terminates  in  every  instance,  with- 
out an  exception,  in  a  blind  extremity. 

4.  That  the  secreting  canals  are  most  diversi- 
fied in  form,  being  simply  sacculated,  branch- 
ing, pennitifid,  nail-shaped,  or  enlarged  at  the 
commencement,  cellular,  berry-shaped,  serpen- 
tine. 

5.  That  granules  or  acini  in  the  hypothetical 
sense  of  writers  do  not  in  reality  exist. 

6.  That  whatever  may  be  the  variety  of  form 
it  is  always  subordinate  to  the  grand  principle 
which  the  whole  glandular  system  displays, — 
namely,  that  the  largest  possible  extent  of 
secreting  surface  is  contained  in  the  smallest 
possible  space. 

7.  That  there  is  no  immediate  connexion  or 
continuity  between  the  secreting  canals  and  the 
sanguiferous  vessels. 

Hypotheses  respecting  the  minute  structure 
of  glands. — I  was  desirous  in  the  first  part 
of  this  article  to  convey  to  the  reader  a  com- 
prehensive view  of  the  glandular  structure, 
unincumbered  by  any  reference  to  the  opinions 
of  anatomists  on  this  subject;  but  the  hy- 
potheses of  Malpighi  and  Kuysch  have  so 
long  divided  the  world  of  science,  that  it  is 
necessary  to  ascertain  how  far  the  doctrines 
advocated  by  those  celebrated  men  are  in 
accordance  with  the  above-stated  conclusions. 
In  doing  this,  however,  much  difficulty  is 
experienced,  especially  in  considering  the 
opinions  of  Malpighi,  inasmuch  as  his  com- 
parisons of  the  minute  structure  of  the  liver, 
of  which  organ  he  principally  treated,  are  very 
vague  and  obscure,  and  being  for  the  most  part 
unaccompanied  by  illustrative  plates,  it  is 
almost  impossible  in  many  of  his  descriptions 
to  detect  the  meaning  he  wishes  to  convey. 
But,  notwithstanding  these  obstacles,  it  is 
evident,  on  studying  his  account  of  the  liver 
and  kidney,  that  justice  has  not  been  done 
to  his  researches;  for  he  not  only  corrected 
many  of  the  then  prevailing  errors,  but  also 
ascertained  several  important  points  connected 
with  this  interesting  branch  of  anatomy. 

Malpighi  compares  the  minute  lobules  of 
the  liver  and  other  conglomerate  glands  to 
a  bunch  of  grapes,  these  lobules  being  joined 
to  the  neighbouring  lobules  by  intermediate 
vessels.  His  words  are,  ':  for  as  an  entire 
bunch  of  grapes  is  formed  of  small  bunches 
by  a  communion  and  tying  together  of  vessels, 
which  small  bunches  are  themselves  formed 


into  a  mass  by  appended  grapes  (acini);  so 
the  whole  liver  is  formed  by  lobules  many 
times  folded,  and  which  are  themselves  formed 
of  glandular  globules."*  It  is  thus  observed 
that  Malpighi  describes  in  the  liver  larger  and 
smaller  lobules  ;  and  it  is  to  these  latter  that 
the  celebrated  but  vague  term  of  acini  appears 
to  be  more  particularly  applied.  He  observes 
that  the  lobules  are  of  various  forms  in  different 
animals  ;  in  fishes  having  the  shape  of  a 
trefoil,  in  the  cat  six-sided,  &c.  The  inter- 
lobular spaces  are  noticed  as  being  distinct 
in  fishes,  but  as  obscure  in  the  more  perfect 
animals. 

With  respect  to  the  intimate  structure  of 
the  small  lobules,  or  acini,  Malpighi  conceived 
that  each  of  them  consisted  of  a  hollow  vesicle, 
receiving  the  secreted  fluid  from  the  small 
arteries  and  conveying  it  into  one  of  the  roots 
or  branches  of  the  hepatic  duct ;  or,  in  other 
words,  that  the  structure  of  the  acinus  was 
the  same  as  that  of  the  simple  mucous  follicle. 
Owing,  however,  to  the  imperfect  means  then 
possessed  of  prosecuting  such  inquiries,  it  is 
certain  that  Malpighi  did  not  detect  the  ultimate 
structure ;  for  more  exact  observations  have 
proved  that  the  last  divisions  of  the  secreting 
canals,  although  they  constantly  terminate  in 
ccecal  extremities,  do  not  always  end  in  follicles, 
but  that  they  may  consist  of  serpentine  tubes, 
as  in  the  kidney,  or  of  pennatifid  canals,  &c. 
It  also  has  been  determined  that  what  he 
regarded  as  the  last  divisions  of  the  ducts,  or 
acini,  are  themselves  composed  of  smaller 
canals.  But  his  observations  on  the  develope- 
ment  of  the  liver  in  the  chick  shew  that  he 
was  acquainted  with  the  essential  facts  con- 
nected with  the  structure  of  that  organ,  and 
with  the  mode  of  its  formation  ;  for  among 
other  interesting  remarks,  he  says  that  on  the 
seventh  day  of  incubation  the  liver  of  a  yellow- 
ish or  ashen  colour  presents  granules  of  rather 
an  oblong  form,  and  "as  it  were  blind  pouches, 
appended  to  the  hepatic  duct."f 

This  hypothesis,  founded  as  it  is  on  so 
large  a  body  of  evidence,  was  generally  re- 
ceived ;  but  the  discovery  of  the  art  of  minute 
injection,  which  seemed  to  afford  ocular  de- 
monstration of  the  fallacy  of  Malpighi's  theory, 
induced  the  majority  of  anatomists  to  adopt 
the  ideas  rather  pompously  announced  by 
Ruysch.  This  celebrated  anatomist,  rejecting 
the  hypothesis  of  Malpighi,  contended]:  that 
he  had  proved,  by  injection,  that  the  arteries 
are  directly  continuous  with  the  excretory 
ducts;  or  that  the  little  ducts  proceed  from 
the  minute  arteries,  like  lesser  from  larger 
brandies ;  and  that  each  acinus  consists  prin- 
cipally of  bloodvessels,  but  contains  also  an 
excretory  duct.§ 

In  considering  the  merits  of  these  two  hy- 
potheses, it  becomes  apparent  that  Ruysch 
supported  his  opinion  by  evidence  of  a  most 
insufficient  character ;  for  in  investigating  the 

*  De  Viscer.  Struct,  cap.  iii.  p.  18. 
t  De  Format.  Pulli  in  Ovo,  p.  20. 
j  Opuscul.  Anat.    de    Fabric.    Gland.  Opera 
omnia,  t.  iii. 
§  hoc  cit.  p.  56,  Jig.  2. 


GLAND. 


491 


roost  complicated  glands  he  relied  solely  on 
his  vascular  injections,  to  the  exclusion  of  the 
evidence  afforded  by  the  much  more  satisfactory 
researches  of  comparative  and  developmental 
anatomy.    If,  as  Professor  Miiller  has  ob- 
served, Ruysch  had  carefully  examined  his 
injected  organs  with  the  microscope,  he  would 
have  found  that  between  the  most  delicate 
plexuses  of  the  bloodvessels  there  is  always 
an  additional  substance  destitute  of  vessels ; 
although  these  organs,  when  seen  by  the  naked 
eye,  appear  to  be  stained  in  every  direction 
with  the  coloured  injection.*     But  even  ad- 
mitting what  frequently  happens  from  a  too 
forcible  injection,  that  the  matter  thrown  into 
the  arteries  is  found  in  the  ducts,  this  does 
not  prove  that  the  small  bloodvessels  are  con- 
tinuous with  the  excretory  canals ;  for  after 
the  sanguiferous  vessels  are  tilled,  they  easily 
become  ruptured,  and  so  allow  their  contents 
to  escape  into  the  ducts.    It  may  further  be 
objected,  that  in  all  the  glandular  organs  which 
have  been  carefully  inspected  the  commence- 
ments of  the  excretory  ducts  are  larger  than 
the   least   arteries  ;f  indeed,   Ruysch's  own 
account  of  this  imaginary  continuity  is  very 
vague,  and  the  plates  designed  to  illustrate 
his  theory,  especially  that  of  the  kidney,  are 
any  thing  but  satisfactory.     As  Ruysch  did 
not  employ  the  microscope,  it  is  impossible 
he  could  have  seen  that  continuity  which  he 
so  confidently  described ;  indeed,  as  Haller 
remarks,^  'l 's  difficult,  or  rather  as  we  should 
say  impossible,  to  demonstrate,  with  the  aid 
of  the  most  powerful  lens,  the  connexion  of 
the  last  arteries  with  the  coats  of  the  ducts. 

Not  only  did  Ruysch  adopt  a  most  in- 
sufficient mode  in  prosecuting  his  inquiries, 
but  he  assumed  as  a  fact  what  was  in  reality 
a  mere  hypothesis,  that  secretion  can  only  take 
place  from  the  open  mouths  or  orifices  of  the 
secerning  arteries.  The  only  point,  therefore, 
which  he  discussed  was,  whether  the  passage 
of  the  arteries  into  the  excretory  ducts  takes 
place  gradually  and  insensibly,  or  suddenly 
and  by  the  intervention  of  a  follicle;  for  it 
never  occurred  to  the  anatomists  of  those  times, 
or  even  to  Haller  and  his  contemporaries,  that 
canals  closed  at  their  end  by  cul-de-sac,  and 
without  open  arterial  mouths,  could  secrete. § 

*  Loc.  cit.  p.  8,  §  4. 

t  Diameter  of  secreting  canals. 

Line 

Parotid  gland  .  .  .  0  0099  (Weber). 
Kidney      ....        0-0166  (Meckel). 

Ditto  0-0180  (Weber). 

Testis       ....        0  0564  (Miiller). 

Ditto   0  0648  (Lauth). 

Liver  (in  rabbits)     .       .        0  0140  ( Miiller). 
Diameter  of  capillary  bloodvessels. 

Line  Line 
Parotid         .       .    0  0030  to  0-0039  (Weber). 
Kidney     .       .        0  0044  to  0  0069  (Miiller). 
Testis    .       .       .    0  0030  to  0  0035  (Weber). 

Burdach  Physiol.  Fiinfter  Band.  p.  38.  For 
measurements  in  otber  glands,  see  Miiller  De 
Gland.  Struct,  p.  112;  Valentin  Handb.  der  En- 
twickelungs-geschichte,  p.  535  et  seq. 

}  El.  Phy.  t.  ii.  p.  378. 

$  The  existence  of  open  mouths  in  the  arteries 
of  the  serous  membranes,  where  they  are  generally 


But  the  true  opinions  of  Malpighi  did  not 
refer  to  the  exact  mode  of  termination  pos- 
sessed by  the  arteries;  nor  did  he  imagine 
that  any  particular  machine  or  follicle  was 
interposed  between  the  arteries  and  the  ducts  : 
his  observations  were  rather  directed  to  the 
more  important  circumstances  relative  to  the 
disposition,  formation,  and  extent  of  the  true 
secreting  canals. 

In  concluding  these  remarks  on  the  hypo- 
thesis of  Malpighi,  it  is  due  to  the  character 
of  that  illustrious  cultivator  of  anatomical  sci- 
ence to  state  that  his  views  are  highly  phi- 
losophic, and  in  a  general  manner  correct — 
that  they  are  supported  by  numerous  obser- 
vations made  on  the  glands  of  the  lower  ani- 
mals, as  well  as  on  the  development  of  the 
liver  during  incubation — and  that  he  had  thus 
the  sagacity  to  adopt  the  mode,  which  expe- 
rience has  shown  is  alone  capable  of  resolving 
this  difficult  question. 

It  would  be  superfluous  to  enter  into  a  de- 
tailed account  of  the  opinions  advanced  by 
later  anatomists,  as  they  are  for  the  most  part 
simply  modifications  of  the  hypothesis  either 
of  Malpighi  or  of  Ruysch.  A  few  general 
observations  will  therefore  suffice. 

Ferrein  has  the  merit  of  being  the  first  wri- 
ter who  pointed  out  in  a  more  distinct  manner 
than  had  been  done  by  Malpighi,  the  great 
importance  of  what  are  erroneously  called  the 
excretory  ducts,  but  which  constitute,  as  we 
have  already  shown,  the  true  secerning  struc- 
ture, lie  remarks  *  that  the  cortical  part  of  the 
kidney  is  composed  of  a  collection  of  white 
cylindrical  tubes,  variously  folded  on  them- 
selves (canales  corticales,  or  ducts  of  Ferrein,) 
and  he  thought  he  had  seen  the  same  tubes  in 
the  liver.  The  serpentine  cortical  canals  have 
been  seen  in  birds  by  Galvani,  to  be  filled  with 
cretaceous  urine  after  the  ligature  of  the  ureter. 
Although  the  researches  of  Ferrein  are  very 
important,  yet  they  want  that  support  from 
comparative  anatomy,  by  which  means  alone 
they  could  have  been  made  subservient  to  esta- 
blish any  general  principles. 

To  Rolando  belongs  the  honour  of  having 
demonstrated  the  mode  in  which  the  glands 
are  developed  from  the  alimentary  canal.  By 
carefully  conducted  observations  on  the  in- 
cubated egg,  he  discovered  that  each  of  these 
organs  in  the  first  instance  consists  of  an  ele- 
vation or  tubercle  of  the  intestine,  which  sub- 
sequently becomes  hollowed  and  forms  a  canal 
directly  continuous  with  that  of  the  intestine. 
He  also  distinctly  announced  what  has  since 
been  demonstrated  in  all  its  details,  that  the 
lungs  are  formed,  like  the  glands,  by  a  pushing 
out  of  the  upper  end  of  the  intestinal  tube ; 
and  he  further  describes  the  mode  in  which 
the  bronchi  and  their  subdivisions  are  deve- 
loped.  The  error  of  those  writers  who  contend 

called  exhalants,  has  never  been  proved  ;  on  the 
contrary,  on  examining,  with  a  powerful  micro- 
scope, the  circulation  of  the  peritoneum  in  rabbits, 
1  have  repeatedly  observed  that  the  small  arteries, 
after  ramifying  in  a  very  complicated  manner, 
become  distinctly  continuous  with  the  little  veins. 
*  Mem.  de  l'Acad.  Roy.  des  Sc.  1749,  p.  492. 


492 


with  Ruysch  that  the  bloodvessels  and  the 
secreting  canals  are  continuous  with  each  other, 
is  clearly  shown ;  in  short,  Rolando  was  the 
first  modern  anatomist,  who,  following  in  the 
footsteps  of  Malpighi,  pointed  out  the  manner 
in  which  the  inquiry  ought  to  be  prosecuted, 
and  thus  laid  the  foundation  of  those  laborious 
and  interesting  researches  for  which  science  is 
principally  indebted  to  the  German  anatomists, 
and  by  which,  within  the  last  few  years,  the 
subject  of  the  glandular  organization  has  been 
so  strikingly  elucidated.* 

Development. — The  investigations  of  Har- 
vey, Malpighi,  Rolando,  Weber,  Meckel,  Bar, 
Valentin,  Rathke,  Miiller,  and  many  other 
anatomists,  have  very  satisfactorily  determined 
the  manner  in  which  the  glands  are  in  general 
developed.  It  is,  however,  necessary  to  pre- 
mise that  these  observations  principally  relate 
to  those  glandular  organs  which  are  appended 
to  the  alimentary  canal,  especially  the  salivary 
glands,  the  pancreas,  and  liver ;  for  as  regards 
the  development  of  those  glands  that  are 
subordinate  to  the  secretion  of  urine  and  to 
generation,  comprising  essentially  the  kidney 
and  the  testis,  much  uncertainty  still  prevails, 
although  it  is  rather  generally  believed  that  the 
corpora  Wolffiana,  or  false  kidneys,  are  in  some 
way  or  other  connected  with  their  primary  for- 
mation.f 

From  the  researches  that  have  been  made 
with  so  much  care,  we  learn  that,  although 
there  are  many  modifications  of  the  formative 
process  in  the  different  classes  of  the  glandular 
organs,  there  are  yet  certain  fixed  laws  in 
obedience  to  which  they  are  produced.  As  the 
development  of  the  individual  glands  is,  how- 
ever, considered  in  the  several  articles  on  those 
organs,  it  is  only  requisite  to  describe  in  this 
place  in  a  general  manner,  and  without  no- 
ticing the  modifications  of  the  general  rule, 
the  process  of  formation.  In  prosecuting  this 
inquiry  two  different  objects  present  themselves 
for  examination, — the  primitive  substance  in 
which  the  gland  is  developed,  and  the  internal 
component  parts,  consisting  essentially  of  the 
secreting  tubuli  and  the  bloodvessels. 

1.  Every  gland  is  formed  from  a  portion  of 
the  primary  plastic  and  amorphous  mass 
( blastoderma )  of  which  the  body  of  the  embryo 
consists. 

2.  This  mass  is  at  first  gelatinous,  extremely 
delicate  and  diaphanous ;  it  subsequently  be- 


*  Journ.  Comp.  des  Sc.  Med.  xvi,  p.  54,  p.  57. 
P.  b'3.  The  honour  of  discovering  the  mode  in 
which  the  glands  appended  to  the  alimentary  pas- 
sage are  formed  by  pushings-out  of  that  tube  has 
been  by  Burdach  improperly  attributed  to  Rathke. 

t  It  would  be  inconsistent  with  the  perfection 
of  the  formative  process  to  conceive  that  either  the 
kidney  or  the  testis  requires  the  aid  of  any  other 
glandular  organ  for  their  development ;  besides 
which  it  may  be  mentioned  that  there  is  no  actual 
connexion  between  the  above  glands  and  the  corpora 
Wolffiana.  Rathke  observes.  "  Although  they 
(corpora  Wolffiana)  are  not  organically  connected 
with  the  kidneys  and  genital  organs,  they  appear 
to  be,  in  an  early  period  of  the  life  of  the  embryo, 
the  precursor  or  representative  of  the  kidney." 
Burdach,  II.  Band.  p.  646. 


GLAND. 

comes  thicker  and  less  transparent.  In  the 
beginning  it  is  solid,  and  in  the  case  of  those 
glands  which  are  appended  to  the  alimentary 
canal, — that  is  to  say,  the  salivary  glands,  the 
liver,  and  the  pancreas,  (and  the  same  laws 
are  observed  in  the  formation  of  the  lungs,*) 
it  appears  as  a  projection  on  the  mucous  mem- 
brane.   (Fig.  222,  A.) 


a 

B 

■PiL 

a 

6 

D 


A  plan  designed  to  show  the  first  origin  of  the  glands. 

a,  b,  alimentary  canal ;  g,  gland.  (The  letters 
have  the  same  signification  in  A,  B,  C,  D.) 

3.  In  a  short  time  this  rounded  mass  begins 
to  project  on  its  external  surface,  and  thus 
forms  a  number  of  lobes,  or,  as  it  were,  little 
islands,  which,  by  the  continuation  of  the  same 
process,  become  more  and  more  numerous  and 
smaller  in  size;  and  thus, according  to  the  cha- 
racter of  the  gland  examined,  are  at  length 
formed  all  the  minute  lobes  of  which  it  con- 
sists. (Fig.  222,  B.) 

4.  Simultaneously  with  this  development  of 
the  outer  surface  of  the  plastic  mass,  but  quite 
independently  of  it,  a  metamorphosis  is  going 
on  within,  by  which  the  internal  canals,  which 
subsequently  become  the  secreting  tubes,  are 
formed.  In  the  first  instance  a  hollow  or 
cavity  is  noticed  communicating  with  the  tube 
of  the  intestine,  and  which  subsequently  be- 
comes the  principal  or  excretory  duct.  When 
it  first  appears  it  is  a  simple  sac,  (fig.  222,  C,) 
but  in  proportion  as  the  projections  or  lobes 
are  formed  on  the  external  surface,  lateral 
branches  are  added  to  the  principal  duct ;  and 
these  again  become  more  and  more  ramified, 
till  an  indefinite  number  of  tubes  are  formed. 
(Fig.  Ill,  D.) 

*  Rathke,  in  Burdach's  Phy.  II.  Band.  p.  580, 
edit.  1837.    Valentin,  1.  c.  p.  501  et  seq. 


GLAND. 


493 


This  development  of  coecal 
tubuli  is  seen  in  the  liver  of 
Limrueus  stagnulis  in  the  em- 
bryo state,  (fig.  223).  In 
the  embryo  of  Lacerta  vi- 
ridis,  (fig.  224,)  the  rudimen- 
tary liver  with  its  blind  se- 
creting canals  (e)  are  observed; 
the  elongated  heart  (a)  fur- 
Fig.  224. 


nishing  the  aorta  (6)  dividing  into  its  right  and 
left  trunks,  together  with  the  principal  venous 
trunk  (c ),  are  represented ;  d  is  the  intestine, 
/  the  rudiment  of  the  corpora  Wolffiana,  and 
g  g  the  rudiments  of  the  upper  and  lower 
extremities. 

One  of  the  most  remarkable  differences  ob- 
served in  the  development  of  the  several  glands 
relates  to  the  proportion  between  the  mass  of 
the  primary  plastic  substance,  and  the  extent 
and  number  of  the  contained  tubes  ;  thus,  in 
the  evolution  of  the  liver  there  is  seen  a  thick 
layer  of  the  primitive  matter ;  whilst,  on  the 
contrary,  the  parotid  gland  in  the  embryo  of  a 
calf  two  inches  seven  lines  long,  consists  of  a 
tube  visible  to  the  naked  eye,  and  not  at  all 
covered  by  parenchyma. 

5.  The  mode  in  which  the  secondary  tubes 
are  developed  has  been  observed  with  great 
care;  and  it  is  distinctly  established  that  they 
do  not  proceed  as  mere  elongations  of  the  pri- 
mary cavity,  but  are  formed  in  an  indepen- 
dent manner.  One  of  the  latest  writers  on  the 
development  of  the  body,  Valentin  *  has 
given  a  very  exact  account  of  the  process  in  all 
the  glands.  He  states  that  in  the  neighbour- 
hood of  the  chief  duct  or  of  a  branch  of  it, 
small  oblong  accumulations  of  the  plastic 
mass  are  formed,  which  become  hollowed  in 
the  interior,  and  these  hollows,  at  first  inde- 
pendent of  the  principal  cavity,  subsequently 
communicate  with  it.  It  is  also  observed  by 
Muller  that  in  the  kidney  of  Batrachian  Am- 
phibia, the  secreting  tubes  first  appear  as 

*  Loc.  cit.  p.  521,  et  alibi. 


vesicles  which  are  formed  before  the  ureter, 
and  therefore  independently  of  the  principal 
duct.*  As  the  tubes  become  more  developed, 
the  plastic  substance  around  them,  by  acquiring 
greater  firmness,  constitutes  their  walls,  and 
thus  determines  their  exact  form  and  limits. 
It  is  necessary  to  state  that  in  every  instance 
without  an  exception,  the  newly-formed  canals 
end  in  coecal  extremities,  which  are  often 
rather  swollen,  presenting  a  pedunculated  ap- 
pearance. 

6.  In  proportion  as  the  canals  become 
formed  in  the  substance  of  the  plastic  mass, 
this  latter  gradually  diminishes  in  quantity, 
till  ultimately,  when  all  the  tubuli  are  formed, 
it  is  so  much  reduced  that  it  merely  fills  up  the 
interlobular  fissures,  and  is  in  fact  converted 
into  the  interstitial  cellular  tissue. 

7.  At  the  same  period  of  time  that  the  tubes 
are  thus  being  formed,  the  bloodvessels  are 
being  developed ;  and,  as  Muller  and  Valentin 
remark,  a  very  close  parallel  is  presented  in  the 
generation  of  these  the  essential  parts  of  the 
gland.  As  in  the  case  of  the  tubes,  there  are 
at  first  little  masses,  or  islands,  of  the  plastic 
substance,  which  subsequently  join  together, 
and  their  interior  becoming  liquified,  a  num- 
ber of  little  channels  are  formed  containing  a 
circulating  fluid,  and  which  channels,  by  the 
subsequent  consolidation  of  their  walls,  are  at 
length  formed  into  perfect  bloodvessels.  Like 
the  tubes  these  vessels  are  at  first  independent ; 
they  afterwards  open  into  larger  trunks  and 
ultimately  into  the  heart.  It  is  proper  to 
remark  that,  although  there  is  such  a  corres- 
pondence in  the  process  of  development  in 
each  instance,  the  bloodvessels  are  formed 
quite  independently  of  the  canals ;  that  they 
occupy  a  different  part  of  the  plastic  mass; 
and  that  they  never  present  that  continuity 
which  ought  at  this  epoch  to  have  been  very 
apparent,  if  the  theory  of  Ruysch  had  been 
founded  in  truth. 

8.  The  several  glands  are  not  developed 
equally  early,  some  having  their  organization 
much  more  advanced  than  others;  thus  at  the 
time  when  the  pancreas  is  so  far  formed  as  to 
contain  an  immense  number  of  canals,  the 
parotid  presents  only  a  single  duct  or  a  few 
ramifications.f  The  principle  which  regulates 
the  relative  degree  of  development  has  evi- 
dently reference  to  the  importance  of  the  organ 
during  the  foetal  life ;  and  in  this  respect  the 
liver  is  most  remarkable,  for  that  body  being, 
as  I  conceive,  the  true  decarbonising  organ  in 
the  animal  kingdom,  and  therefore  its  func- 
tions being  doubtless  necessary  in  the  foetus, 
very  quickly  acquires  a  high  degree  of  organi- 
zation, so  much  so  that,  as  we  learn  from  all 
observations,  it  very  speedily  fills  the  greatest 
part  of  the  abdomen. J 

*  De  Gland.  Struct,  p.  87. 

t  Rathke  in  Burdach's  Phy.  II.  Band.  p.  576. 
Valentin,  1.  c.  p.  225. 

$  In  the  embryo  of  a  sheep  five  lines  in  length, 
Valentin  has  found  the  liver  filling  half  of  the 
abdominal  cavity;  and  in  the  embryo  eight  lines 
long,  that  organ  constitutes  three-fourths  of  the 
bulk  of  the  viscera  contained  in  the  peritoneum: 


494 


GLOSSO-PIIARYNGEAL  NERVE. 


Lastly,  The  laws  in  obedience  to  which  the 
glands  are  developed,  are  as  universal  as  to 
their  existence  in  the  animal  kingdom,  as  those 
which  regulate  the  formation  of  the  nervous, 
osseous,  and  vascular  systems ;  and  thus  it 
may  be  noticed  that  the  complex  glands  of 
man  and  the  mammalia,  such  as  the  parotid, 
the  pancreas,  and  the  liver,  pass,  in  the  various 
epochs  of  their  development,  through  those 
forms,  which  in  the  lower  animals,  and  espe- 
cially in  the  invertebrated  tribes,  constitute  the 
permanent  structure.  It  may  also  be  stated, 
that  when  any  particular  gland  first  appears  in 
the  animal  series,  it  presents  the  most  simple 
structure,  although  the  same  gland  in  the 
higher  classes  acquires  the  highest  degree  of 
complexity.  Thus,  the  liver  in  insects  is  tu- 
bular, and  in  many  of  the  amphibia  excavated 
into  large  cells ;  the  pancreas  in  fishes  consists 
of  separate  tubuli;  the  salivary  glands  of  birds 
are  extremely  simple ;  so  also  are  the  mam- 
mary glands  in  the  Cetacea,  and  the  prostate 
glands  in  many  of  the  Mammalia. 

Bibliography.  —  Malpighi,  De  vise,  struct, 
cap.  iii.  p.  18,  et  alibi  ;  De  format.  Pulli  in  ovo, 
p.  20.  Ruysch,  Opera  omnia,  torn.  iii.  Holler, 
Elem.  Phys.  ii.  Ferrein,  Mem.  de  l'Acad.  Roy. 
des  Sc.  1749.  Cuvier,  Lei;ons  d'Anat.  Comp.  torn, 
iv.  Rolando,  Journ.  Comp.  des  Sc.  Med.  torn.  xvi. 
The  Treatises  of  Bichat,  Meckel,  and  Beclard  on 
Gen.  Anat.  Miiller,  De  gland,  secernent,  struct, 
penit.  Handb.  der  Phy.  I.  Band.  p.  418.  Trans, 
of  ditto  by  Baly,  vol.  i.  p.  441.  Burdach,  Phy. 
II.  Band.  edit.  1837,  pp.  258,  264,  287,  376,  375, 
et  alibi.  This  volume  contains  a  large  collection 
of  the  most  important  facts  relative  to  the  deve- 
lopment of  the  several  organs,  V.  Band.  p.  36 
et  seq.  Kiernan  in  Phil.  Trans.  1833.  Valentin, 
Handb.  der  Entwickelungs -geschichte,  pp.  495, 
514,  521,  533.  Boer,  De  ovo  Mammal.,  and  in 
Burdach's  Phy.  Cants,  Anat.  Comp.  par  Jour- 
dan,  torn.  ii.  Grant's  Lect.  on  Comp.  Anat.  in 
Lancet,  1833-34.  Blumenbach,  Man.  of  Comp. 
Anat.  by  Coulson.  Berres,  Die  Mikroskopischen 
Gebilde  des  Menschlichen  Kbrpers. 

( R.  D.  Grainger.) 

GLOSSO  -  PHARYNGEAL  NERVE 
(nervus  glosso-pharyngeus ;  part  of  the  sixth 
pair  of  Galen  and  the  older  anatomists  ;  part 
of  the  eighth  pair  of  Willis  ;  the  ninth  pair  of 
Soemmerring  and  some  of  the  modern  anato- 
mists). The  glosso-pharyngeal,  par  vagum,  and 
spinal  accessory  nerves  were  long  considered 
as  forming  a  single  nerve.  Willis  first  clearly 
pointed  out  the  origin  and  course  of  the  spinal 
accessory,  separated  it  from  the  par  vagum,  and 
termed  it  the  nervus  accessorius.  The  glosso- 
pharyngeal appears  to  have  been  generally  de- 
scribed at  the  time  of  Willis  as  a  branch  of  the 
par  vagum.  The  term  glosso-pharyngeal  was 
not  applied  to  it  until  the  time  of  Huber* 
Previous  to  the  time  of  Willis,  however,  some 
anatomists,  more  particularly  Fallopius,t  Eu- 

(1.  c.  p.  517.)  Similar  observations  have  been 
made  in  other  animals  and  in  the  human  embryo 
by  Meckel. 

*  Epistola  Anat.  de  Nervo  Intercostali,  De 
Nervis  Octavi  et  Noni  Paris,  &c.  p.  17.  Goet. 
1744. 

f  Opera  quae  adhuc  existant  omnia,  p.  455. 
Francof. 


stachius,*  Bauhinus,f  had  shown  that  this  nerve 
was  really  not  a  mere  branch  of  the  par  vagum. 
The  same  thing  was  stated,  more  or  less  strongly, 
by  many  subsequent  anatomists,  more  particu- 
larly by  Winslow,];  Haller,§  and  Vicq  D'Azyr.|| 

Soemmerringlf  and  Andersch**  were,  how- 
ever, the  first  who  fairly  separated  the  glosso- 
pharyngeal from  the  par  vagum,  and  ranked  it 
as  a  distinct  nerve.  The  glosso-pharyngei  form 
the  ninth  pair  of  Soemmerring's  classification 
of  the  encephalic  nerves,  and  were  termed  the 
eighth  pair  by  Andersch.  There  can  be  no 
doubt  that  if  we  adopt  the  numerical  method 
of  naming  these  nerves,  the  glosso-pharyngei 
properly  form  the  ninth  pair.  To  avoid,  how- 
ever, all  the  misunderstanding  which  is  apt 
to  arise  from  the  use  of  numerical  names 
when  applied  to  these  nerves,  the  best  designa- 
tion for  the  nerve  at  present  under  our  conside- 
ration is  the  glosso-pharyngeal,  derived  from  its 
being  principally  distributed  upon  the  tongue 
and  the  pharynx.  I  need  scarcely  state  that, 
under  the  term  eighth  pair,  as  it  is  most  gene- 
rally used  in  modern  writings,  is  included  the 
glosso-pharyngeal,  par  vagum,  and  spinal  ac- 
cessory nerves,  ff 

Origin. — The  glosso-pharyngeal  nerve  arises 
by  from  two  to  six  filaments  from  the  restiform 
body  of  the  medulla  oblongata,  closely  upon 
the  groove  which  separates  the  restiform  from 
the  olivary  body.  At  its  origin  it  is  placed  im- 
mediately above  and  in  the  same  line  with  the 
par  vagum  nerve,  and  between  it  and  the  portio 
dura  of  the  seventh  pair.  lis  lower  margin  is 
generally  separated  from  the  upper  margin  of 
the  par  vagum  by  a  few  small  bloodvessels. 

From  its  origin  it  first  proceeds  outwards 
along  with  the  par  vagum  and  spinal  accessory 
to  reach  the  foramen  lacerum  posterius. 
Through  the  anterior  and  inner  part  of  this 
foramen  it  escapes  from  the  interior  of  the  cra- 
nium, and  is  enclosed  in  a  strong  and  separate 
sheath  furnished  by  the  dura  mater.JJ  In  its 
passage  through  the  foramen  lacerum  it  is 
placed  anterior  to  the  par  vagum  and  spinal 
accessory  and  the  commencement  of  the  inter- 

*  Explicatio  Tabularum  Anatomicarum  Eusta- 
chii,  tab.  xviii.    Bat.  1744. 

t  Theatrum  Anatomicum,  cap.  xxiii.  p.  659. 
Francof.  1605. 

\  Exposition  Anatomiqne  de  la  Structure  du 
Corps  Humain,  torn.  iii.  p.  106.    Amstel.  1743. 

$  Elementa  Physiol,  torn.  iv.  cap.  xxix.  p.  231-2. 
Laus.  1562. 

||  Traite  d'Anatomie  et  de  Physiologie  avec  des 
planches  coloriees,  etc.  No.  iii.  p.  56.    Paris,  1786. 

If  De  Basi  Encephali  et  Originibus  Nervorum, 
&c.  in  torn.  ii.  p.  97.  Ludwig.  Script.  Neurol. 
Sel.  Min.  1792. 

**  Fragmentum  Descrip.  Nerv.  Cardiac,  in  torn, 
ii.  Ludwig.    Sc.  Neur.  Sel.  Min.  p.  113. 

ft  Those  who  may  wish  to  examine  at  greater 
length  the  literature  of  this  nerve  may  consult 
Soemmerring  Oper.  Cit.  p.  97,  and  more  particu- 
larly Kilian  Anatomische  Untersuchungen  iiber 
dasneunte  Himnervenpaar  oderden  Nervus  Glosso- 
pharyngeus,  p.  1-62.    Pesth,  1822. 

|t  According  to  Morgagni  (Adversar.  Anat.  vi. 
Animad.  xii.)  and  Wrisberg  (De  Nervis  Pharyn- 
gis,  in  torn.  iii.  p.  52.  Ludwig.  Script.  Neur.  Sel. 
Min.)  this  septum  separating  the  glosso-pharyn- 
geal from  the  par  vagum  is  sometimes  osseous. 


GLOSSO-PHARYNGEAL  NERVE. 


495 


nal  jugular  vein,  which  lie  in  the  order  here 
enumerated.    As  the  nerve  issues  from  the 
lower  part  of  the  foramen  lacerum  it  forms  a 
small  rounded  chord,  close  to,  but  still  quite 
separate  from  the  par  vagum,  and  is  situated 
between  the  internal  jugular  vein  and  internal 
carotid  artery.    It  now  leaves  the  trunk  of  the 
par  vagum,  proceeds  downwards,  inwards,  and 
forwards,  passing  in  front  of  the  internal  carotid 
artery  and  behind  the  styloid  muscles,  and 
joins  itself  to  the  stylo-pharyngeus  muscle.  It 
runs  at  first  along  the  lower  margin  of  this 
muscle,  and  rests  on  the  superior  constrictor 
of  the  pharynx  which  separates  it  from  the 
tonsil ;  it  then  mounts  on  the  anterior  surface 
of  the  stylo-pharyngeus  muscle,  and  passes  be- 
tween it  and  the  stylo-glossus  to  reach  the  base 
of  the  tongue,  upon  which  it  is  ultimately  dis- 
tributed.   Occasionally,  instead  of  turning  over 
the  lower  edge  of  the  stylo-pharyngeus,  it  per- 
forates this  muscle.    In  following  the  course 
here  described,  it  forms  a  slight  curve,  the  con- 
vexity of  which  looks  downwards,  and  it  sends 
off  several  branches,  which  are  principally  dis- 
tributed to  the  pharynx  and  isthmus  of  the 
fauces.    These  branches  vary  very  considerably 
in  size  and  in  number  in  different  subjects,  but 
the  general  distribution  of  the  nerve  is  in  all 
cases  nearly  the  same.    When  the  branches 
are  few  in  number,  this  is  compensated  for  by 
their  increased  bulk,  and  when  they  are  more 
numerous  they  are  of  diminished  size.  This 
nerve  generally  anastomoses  with  the  par  vagum 
within  the  cranium  by  a  pretty  distinct  branch.* 
As  the  nerve  lies  within  the  foramen  lacerum  it 
presents  two  swellings  or  ganglia  upon  it,  and 
gives  off  some  small  branches.  The  superior  of 
these  two  ganglia  is  considerably  smaller  than  the 
inferior,  and  has  been  termed  die  ganglion  ju- 
gidareby  J.  Muller,  (fig.  225).  It  is  described 
by  Mullerf  as  generally  present,  though  small, 
placed  upon  the  posterior  or  external  side  of 
the  nerve,  and  situated  at  the  cranial  end  of 
the  foramen  lacerum.    It  can  only  be  distinctly 
seen  after  the  dura  mater  has  been  removed, 
and  the  upper  margin  of  the  opening  chiseled 
away.    I  have  repeatedly  observed  this  gan- 
glion jugulare  in  the  human  subject.    In  one 
case  which  I  lately  dissected,  where  it  was 
comparatively  large,  very  distinct,  and  pre- 
sented undoubtedly  all  the  appearance  of  a 
true  ganglion,  it  appeared  to  me,  after  careful 
examination,  that  this  swelling  does  not  include 
the  whole  of  the  nerve,  but  is  confined,  as 
Muller  states,  to  the  posterior  filaments.  These 
posterior  filaments  do  not  seem  to  differ  other- 
wise in  appearance  from  the  anterior.  This 
ganglion  was  first  pointed  out  by  Ehrenritter, 
and  mentioned  by  Soemmerring  on  his  autho- 
rity.J    Very  little  attention  seems  to  have  been 
paid  to  this  ganglion,  so  that  when  it  was  lately 
re-described  by  Muller,§  it  was  supposed  that 

*  Op.  cit.  p.  114. 

t  Handbuch  der  Physiologie  des  Menschen. 
Erster  Band,  p.  589. 

t  Arnold  in  Tiedemann's  Zeitschrift  fur  Physio- 
logie, vol.  ii.  p.  175,  and  J.  Muller,  in  his  Archiv. 
fur  Anat.  und  Phys.  &c.  1837.    No.  ii.  p.  275. 

j>  In  Vergl.  Jahresbericht  Von  1833,  Archiv.  fur 
Anatomie  und  Physiol.  1834,  p.  11. 


its  existence  in  the  human  subject  had  been 
hitherto  unknown.*  Mayer,  of  Bonn,  had, 
previous  to  this  (1833),  described  two  small 
swellings  upon  the  root  of  the  glosso-pharyn- 
geal  in  the  ox,  but  he  failed  to  detect  any 
similar  ganglion  in  the  human  species.  No 
nervous  filaments  either  leave  or  join  that  part 
of  the  trunk  of  the  nerve  upon  which  the  gan- 
glion jugulare  is  placed.  The  inferior  ganglion 
(ganglion  petrosum,  ganglion  of  Andersch)  is 
considerably  larger  than  the  superior,  is  of  an 
oblong  shape,  and  includes  all  the  filaments  of 
the  nerve.  It  is  described  by  Anderschf  as 
about  five  lines  in  length,  and  commencing 
about  four  lines  below  the  place  where  the 
nerve  perforates  the  dura  mater.  No  doubt,  if 
we  include  all  that  portion  of  the  trunk  of  the 
nerve  which  appears  to  be  somewhat  increased 
in  size,  it  may  sometimes  measure  five  lines, 
but  the  true  gangliform  enlargement  is  consi- 
derably less.  As  WutzerJ  remarks,  it  is  rarely 
found  to  exceed  two  lines  in  length.    This  gan- 


Natural  size.        Magn  ified  about  four  times. 


glion  lies  in  a  distinct  depression  in  the  pe- 
trous portion  of  the  temporal  bone,  which 
Andersch  terms  receptaculum  ganglioli  petrosi. 

Some  branches  both  proceed  from  and  join 
that  portion  of  the  nerve  occupied  by  this  gan- 
glion petrosum.  The  most  important  of  these 
is  a  small  branch  which  proceeds  from  the 
ganglion  into  the  tympanum  (ramus  tympani- 
cus  nervi  glosso-pharyngei ;  nerve  of  Jacobson). 
The  course  and  distribution  of  this  branch  were 
partly  known  to  Schmiedal,  Andersch,  Ehren- 
ritter, and  Comparetti,||  but  were  more  fully 

*  I  find  that  Wutzer,  in  his  Monograph  "  De 
Corporis  Humani  Gangliorum  Fabrica  atque  Usu," 
p.  92,  after  describing  the  inferior  ganglion  of  the 
glosso-pharyngeal,  says,  *  secundarium  ganglion 
quod  nonnumquam  adesse  Ehrenritter  contendit 
mini  non  sub  oculos  cecidit." 

t  If  Andersch  is  not  to  be  considered  the  disco- 
verer of  this  ganglion,  it  cannot  be  denied  that  he 
first  gave  a  full  and  clear  description  of  it.  (Op. 
cit.  p.  115.)  Kilian  (Op.  cit.  p.  30  and  75)  con- 
tends that  the  existence  of  this  ganglion  was  known 
to  Winslow.  In  evidence  of  this  he  quotes  the 
following  sentence  from  his  Exposit.  Anatom.  torn, 
iii.  "  les  deux  portions  (nervus  glosso-pharyngeus 
et  nervus  vagus)  sont  edroitement  collees  ensemble 
et  communiquent  de  part  et  d'autre  par  des  filamens 
qui  grossissent  un  peu  la  petite  portion  (glosso- 
pharyngeal.)" 

|  Op.  cit.  p.  91. 

§  [This  figure  is  taken  from  a  dissection  by  Mr. 
Walker  in  the  Webb-street  School  of  Anatomy. 
The  Editor  is  indebted  for  it  to  the  kindness  of  his 
friend  Mr.  Grainger.] 

||  Vide  Muller's  Archiv.  fur  Anat.  und  Physiol. 
&c.   No.  ii.  1837.  p.  281. 


496 


GLOSSO-PHARYNGEAL  NERVE. 


described  by  Jacobson*  Tlie  nervus  tympa- 
nicus enters  a  canal  in  the  petrous  portion  of 
the  temporal  bone,  and  there  anastomoses  with 
the  Vidian  and  the  carotid  plexus  of  the  sym- 
pathetic. The  orifice  of  this  canal  is  placed 
between  the  jugular  fossa  and  carotid  canal, 
and  external  to  the  termination  of  the  aqueduct 
of  the  cochlea.  The  ramus  tympamcus  is 
figured  and  described  by  Arnoldf  as  dividing 
into  six  filaments  :  1.  a  filament  to  the  fenestra 
rotunda ;  2.  one  to  the  fenestra  ovalis ;  3.  one 
which  anastomoses  with  the  sympathetic;  4. 
one  distributed  upon  the  Eustachian  tube ;  5. 
one,  which  he  terms  nervus  petrosus  profundus 
minor,  anastomosing  with  {lie  spheno-palatine 
ganglion ;  6.  one,  the  nervus  petrosus  superfi- 
cialis  minor,  which  anastomoses  with  a  branch 
from  the  otic  ganglion  or  ganglion  Arnoldi. 
The  nerve  of  Jacobson  thus  forms  an  anasto- 
mosis among  the  glosso-pharyngeal,  the  second"' 
and  third  branches  of  the  fifth  pair,  and  the 
superior  ganglion  of  the  sympathetic.;!;  A  small 
branch  arises  from  the  ganglion  petrosum,  as 
delineated  by  Arnold,§  which  unites  itself  to 
the  auricular  branch  of  the  par  vagum.|| 

Two  other  filaments  are  generally  found  con- 
nected with  that  part  of  the  trunk  of  the  nerve 
occupied  by  the  ganglion  petrosum.  These 
are  a  communicating  twig  between  the  ganglion 
petrosum  and  ganglion  of  the  par  vagum,  and 
an  anastomosing  filament  of  the  sympathetic. 
As  these  filaments  are  very  minute,  and  lie  in  a 
dense  fibrous  sheath,  they  can  only  be  displayed 
by  an  exceedingly  careful  dissection.  The 
communicating  filament  between  these  two 
ganglia  of  the  glosso-pharyngeal  and  par  vagum 
is  short,  and  passes  directly  from  the  one  gan- 
glion to  the  other.  The  communicating  filament 
from  the  sympathetic  comes  from  the  superior 
cervical  ganglion,  mounts  up  between  the 
trunks  of  the  par  vagum  and  glosso-pharyngeal, 
and  divides  into  two  portions, — one  of  these 
connecting  itself  to  the  ganglion  petrosum,  the 
other  to  the  ganglion  of  the  par  vagum.  The 
course  and  mode  of  termination  of  this  com- 
municating filament  of  the  sympathetic  is  re- 
presented differently  by  Wutzerlf  from  the  de- 
scription here  given.  I  have  adopted  that 
given  by  Arnold,**  since  it  exactly  agrees  with 
my  own  dissections.  Another  branch  has  been 
described  as  arising  from  the  ganglion  petrosum 
immediately  below  the  ramus  tympanicus,  and 
passing  backwards  behind  the  styloid  process, 
to  anastomose  with  the  trunk  of  the  facial  after 


*  Acta  Reg.  Soc.  Havniensis  Medic,  torn.  v. 
Copen.  1818. 

f  Icones  Nervorum  Capitis,  tab.  vii.  1834. 

$  Cruveilhier  (Anatomie  Descriptive,  torn.  iv. 
p.  952,  1835)  states  that,  in  one  subject  he  found 
this  ramus  tympanicus  formed  by  two  branches, 
one  from  the  par  vagum,  the  other  from  the  glosso- 
pharyngeal. In  another  subject  it  was  formed  by 
a  branch  from  the  auricular  of  the  pneumo-gastric 
united  with  one  from  the  glosso-pharyngeal. 

§  Op.  cit.  plates  iii  and  v. 

II  It  appears  that  the  ramus  auricularis  of  the 
par  vagum  was  described  even  to  both  its  branches 
by  Comparetti,  p.  129,  De  Aure  Interna,  &c. 

1  Op.  cit.  fig.  vii. 

**  Op.  cit.  tab.  iv. 


its  exit  from  the  stylo-mastoid  foramen  *  We 
here  see  that  the  anatomy  of  that  portion  of  the 
glosso-pharyngeal  nerve  which  lies  within  the 
foramen  lacerum  is  very  complicated,  but  it 
must  be  at  the  same  time  obvious  that  it  em- 
braces considerations  of  great  interest  in  a  phy- 
siological point  of  view. 

What  the  true  nature  of  these  two  ganglia  is, 
we  cannot  at  present  venture  positively  to  de- 
cide. I  may  mention,  however,  that  Midler  f 
states  that  he  is  satisfied,  that  the  superior  gan- 
glion or  ganglion  jugulare  resembles  the  Casse- 
rian  ganglion  upon  the  trigeminus  or  fifth  pair, 
and  those  upon  the  posterior  roots  of  the  spinal 
nerves,  for  while  one  portion  of  the  nerve 
swells  into  a  ganglion,  the  other  passes  by 
without  assisting  in  its  formation.  On  the 
other  hand,  he  believes  that  the  inferior  gan- 
glion differs  decidedly  from  those  upon  the 
posterior  roots  of  the  spinal  nerves,  and  resem- 
bles the  swelling  which  is  occasionally  found 
upon  a  nerve  where  it  is  joined  by  branches 
from  the  sympathetic.  The  ramus  tympanicus, 
according  to  his  view,  belongs  to  the  sympa- 
thetic system  of  nerves.}: 

On  escaping  from  the  foramen  lacerum  the 
glosso  -  pharyngeal  occasionally  forms  direct 
anastomoses  with  the  par  vagum,  spinal  acces- 
sory, and  superior  ganglion  of  the  sympathetic; 
at  other  times  it  only  anastomoses  with  these 
through  its  branches. 

Digastric  and  stylo-hyoid  branch.  —  The 
origin  of  this  branch  is  far  from  being  regular. 
It  frequently  arises  from  the  external  side  of  the 
nerve  soon  after  its  exit  from  the  foramen  lace- 
rum. It  ramifies,  as  its  name  implies,  in  the 
digastric  and  stylo-hyoid  muscles.  The  fila- 
ments of  this  nerve  anastomose  in  the  substance 
of  the  digastric  muscle  with  the  digastric  branch 
of  the  portio  dura.§ 

Carotid  branches  are  two  or  more  in  num- 
ber, and  pass  from  the  convexity  of  the  nerve 
or  from  some  of  its  pharyngeal  branches,  and 
proceed  upon  the  surface  of  the  internal  carotid, 
where  they  form  a  very  evident  anastomosis  with 
the  sympathetic,  with  the  pharyngeal,  and  other 
branches  of  the  par  vagum,  and  assist  in  form- 
ing the  plexuses  around  the  carotid  arteries. 
They  have  been  traced  downwards  for  a  consi- 
derable extent,  and  found  to  anastomose  with 
the  superior  and  even  with  the  middle  cardiac 
nerves. 

Pharyngeal  branches. — The  nerve  next  fur- 
nishes the  pharyngeal  branches,  which  are  from 
two  to  four  in  number.  The  largest  of  these 
proceed  downwards,  and  their  ramifications  can 
be  traced  over  the  whole  of  the  pharynx,  but 
more  particularly  over  its  upper  and  middle 

*  Cruveilhier,  op.  cit.  p.  953.  He  looks  upon 
this  twig  as  the  rudiment  of  a  considerable  branch 
of  the  facial,  which  he  found  in  one  case  partly  to 
replace  the  glosso-pharyngeal.  See  also  torn.  iii. 
p.  424. 

t  Archiv.  fur  Anat.  &c.  No.  ii.  1837,  p.  276. 

%  Handbuch  der  Physiol.  Erster  Band. 

§  Mr.  Swan,  in  plate  xvii.  fig.  2  and  3,  of  his 
"  Demonstrations  of  the  Nerves  of  the  Human 
Body,"  figures  this  communication  as  formed  by  a 
filament  of  the  digastric  branch  of  the  facial  going 
to  join  the  trunk  of  the  glosso-pharyngeal. 


GLOSSOPHARYNGEAL  NERVE. 


49T 


portions.  One  or  generally  more  of  these  pha- 
ryngeal branches  perforate  the  stylo-pharyngeus 
muscle,  and  can  be  traced  partly  downwards  up- 
on the  middle  constrictor,  partly  upwards  upon 
the  superior  constrictor  and  mucous  membrane 
of  the  fauces,  and  also  partly  forwards  upon  the 
surface  of  the  tonsils.  1  have  traced  one  of 
these  pharyngeal  branches  through  the  posterior 
part  of  the  hyo-glossus  muscle  into  the  mucous 
membrane  at  the  side  of  the  posterior  part  of 
the  tongue.  These  pharyngeal  branches,  by 
their  anastomoses  with  the  pharyngeal  branches 
of  the  par  vagum  and  pharyngeal  branches  of 
the  sympathetic,  form  what  is  called  the  pha- 
ryngeal plexus  of  nerves!*  A  distinct  swelling 
is  frequently  found  over  the  internal  carotid 
artery,  formed  by  the  confluence  of  the  princi- 
pal pharyngeal  branches  of  the  glosso-pharyn- 
geus,  of  the  superior  pharyngeal  branch  of  the 
par  vagum,  and  the  pharyngeal  branches  of  the 
superior  ganglion  of  the  sympathetic.  This 
swelling  varies  considerably  in  size  and  appear- 
ance. Huberf  describes  a  small  ganglion  in 
the  pharyngeal  plexus.  Haase^  shortly  de- 
scribes this  swelling  as  a  gangliform  enlarge- 
ment. Wrisberg ;§  states  that  a  ganglion,  of  the 
size  of  the  ophthalmic,  is  placed  at  the  conflu- 
ence of  these  nerves.  Scarpa||  describes  and 
figures  it  as  a  gangliform  plexus  more  particu- 
larly connected  with  the  pharyngeal  branch  of 
the  par  vagum.  Wutzer^f  states  that  he  has 
been  unable  to  detect  this  pharyngeal  ganglion. 
Kilian**  and  Arno!d,tf  but  more  particularly 
Rilian,  figure  it  as  a  plexus.  Though  I  would 
not  deny  the  occasional  existence  of  a  small 
ganglion  in  this  region,  yet  I  believe  it  will  be 
found  that  this  swelling  is  generally  formed  by 
the  cellular  tissue  binding  together  these 
branches  as  they  anastomose  with  and  cross 
each  other. \t 

Lingual  branches. — After  the  trunk  of  the 
nerve  lias  furnished  the  pharyngeal  branches,  it 
sends  off  from  its  concave  side  some  small 
twigs  upon  the  surface  of  the  tonsils.  It  then 
forms  the  lingual  portion  of  the  nerve,  passes 
into  the  base  of  the  tongue  below  the  stylo- 
glossus and  posterior  margin  of  the  hyo-glossus 
muscle,  where  it  divides  into  three  or  four 
branches.  The  superior  of  these  is  principally 
distributed  upon  the  posterior  part  of  the  sides 
of  the  tongue,  and  sends  some  twigs  backwards 
upon  the  palato-glossus  muscle  and  mucous 
membrane  of  the  fauces,  where  they  anastomose 
with  the  other  tonsillitic  twigs.  The  middle 
part  of  the  termination  of  the  nerve  passes 

*  A  small  twig  from  the  hypo-glossal  nerve  can 
sometimes  be  traced  into  this  plexus.  As  the  su- 
perior pharyngeal  branch  of  the  par  vagum  is  partly 
formed  by  the  spinal  accessory,  this  last  nerve  must 
assist  in  the  formation  of  this  plexus. 

t  Op.  cit.  p.  18. 

X  De   Nervo   phrenico  dextri    lateris  duplici, 
&c.  Ludwig,  torn.  iii.  p.  115. 
§  Op.  cit.  p.  58. 
jj  Tabulae  Neurologicae,  plate  2. 
1  Op.  cit.  p.  91. 
**  Op.  cit.  tab.  ii.  fig.  5. 
tt  Op.  cit.  tab.  iv. 

XX  The  glosso-pharyngeal  in  the  dog  is  generally 
considerably  increased  in  size  where  the  principal 
pharyngeal  branches  are  given  off. 
VOL.  II. 


through  the  lingualis  and  hyo-glossus  muscles 
to  reach  the  mucous  membrane  and  papilla;  at 
the  side  of  the  base  of  the  tongue.  The  re- 
mainder of  the  nerve  perforates  the  genic-hyo- 
glossus  to  reach  the  mucous  membrane  and 
papilla?  in  the  middle  of  the  base  of  the  tongue. 
The  distribution  of  these  twigs  is  confined  to 
the  mucous  surface  at  the  base  of  the  tongue, 
and  do  not  extend  beyond  an  inch  in  front  of 
the  foramen  coecum.  They  pass  through  the 
muscles  of  the  tongue  without  giving  any  fila- 
ments to  them.* 

Tonsillitic  twigs. — The  different  twigs  of  this 
nerve  which  we  have  described  as  passing  to 
the  tonsils,  form„an  intricate  plexus,  posterior 
to  and  around  these  bodies,  which  has  been 
called  the  circulus  tonsillaris.  These  tonsillitic 
twigs  are  ultimately  intermixed  with  the  as- 
cending filaments  of  the  pharyngeal  branch  of 
the  par  vagum,  and  pass  in  considerable  num- 
bers to  the  isthmus  of  the  fauces  and  soft 
palate.  They  anastomose  also  with  the  pos- 
terior palatine  branches  of  the  second  branch 
of  the  fifth  pair,  and,  according  to  Wrisberg,f 
with  a  filament  from  the  third  branch  of  the 
fifth. 

In  repeated  dissections,  both  upon  the  hu- 
man subject  and  the  dog,  I  have  found,  in 
tracing  the  branches  of  this  nerve  to  their  ulti- 
mate distribution  upon  the  pharynx  and  fauces, 
that  those  branches  of  the  glosso-pharyngeal 
which  do  not  anastomose  with  the  pharyngeal 
branch  of  the  par  vagum  are  principally  distri- 
buted upon  the  mucous  membrane,  and  that 
comparatively  a  small  number  of  these  fila- 
ments seem  to  terminate  in  the  muscular  fibre. 
The  uncombined  twigs  of  the  pharyngeal 
branches  of  the  par  vagum  are,  on  the  other 
hand,  distributed  entirely  to  the  muscular  fibre. 
In  a  dissection  of  this  kind  care  must  be  taken 
to  select  those  twigs  only  which  proceed  to 
their  distribution  without  exchanging  filaments 
with  any  other  nerve.  It  can  be  made  more 
favourably  in  the  dog  than  in  the  human  spe- 
cies. The  glosso-pharyngeus  is  still  distri- 
buted upon  the  tongue  in  birds,  in  the  frog, 
and  certain  of  the  amphibia,  while  this  organ 
receives  no  branch  from  the  fifth  pair,  and  from 
this  circumstance  it  has  been  considered  the 
nervus  gustatorius  of  these  animals. J  In 
fishes  there  is  a  branch  of  the  par  vagum 
called  glosso-pharyngeal,  which  escapes  from 
the  base  of  the  cranium  by  a  separate  opening, 
and  is  distributed  upon  the  gills,  and  also  upon 
the  tongue  as  far  as  the  skin  of  the  mouth. 

Physiology. — It  is  only  to  the  labours  of 
anatomists  and  physiologists  within  the  last 
few  years  that  we  are  to  look  for  any  thing 

*  In  tracing  these  nerves,  it  has  appeared  to  me 
that  a  few  minute  filaments  terminate  in  the  mus- 
cles of  the  tongue,  but  these  are  exceedingly  few 
and  small.  The  statement  of  Wrisberg,  that  the 
deep  branches  of  the  lingual  portion  of  the  glosso- 
pharyngeal are  distributed  to  the  muscles  of  the 
tongue,  is  opposed  to  the  observations  of  the  best 
anatomists,  who  have  since  his  time  examined  the 
ultimate  distribution  of  this  nerve. 

+  Op.  cit.  p.  51. 

X  Handbuch  der  Physiologie,  etc.  ErstcrBand, 
p.  590,  772. 

2  L 


498 


GLOSSO-PHARYNGEAL  NERVE. 


like  accurate  data  in  enabling  us  to  judge  of 
the  functions  of  this  nerve.  Its  deep  situa- 
tion, its  proximity  to  important  parts,  and  the 
consequent  difficulty  of  exposing  it  in  the  living 
animal,  have  until  very  lately  deterred  physio- 
logists from  making  it  an  object  of  experimental 
investigation.  Some  have  supposed  that  it 
supplies  the  nervous  filaments  upon  which  the 
sense  of  taste  at  the  root  of  the  tongue  de- 
pends, while  the  third  branch  of  the  fifth  pair 
furnishes  those  of  the  anterior  part  of  this 
organ.  Mr.  Mayo*  states  that  "  when  this 
nerve  is  pinched  in  an  ass  recently  killed,  a 
distinct  convulsive  action  ensues,  apparently 
including  and  limited  to  the  stylo-pharyngeus 
muscle  and  upper  part  of  the  pharynx."  He 
concluded  from  this  that  the  glosso-pharyngeal 
is  in  part,  probably,  a  nerve  of  voluntary  mo- 
tion ;  and  from  its  distribution  upon  the  sur- 
face at  the  root  of  the  tongue,  that  it  is  also 
partly  a  nerve  of  common  sensation.  Sir  C. 
Bell  believes  that  this  is  the  respiratory  nerve 
of  the  tongue  and  pharynx,  associating  the 
movements  of  those  organs  with  the  muscles 
of  respiration  in  speech  and  in  deglutition. 
And  we  find  it  stated  by  Mr.  Shaw  f  that  its 
power  of  combining  the  movements  of  the 
tongue  and  pharynx  in  deglutition  "  has  been 
shown  by  several  experiments,  the  results  of 
which  were  very  curious,  and  corroborative  of 
the  views  deduced  from  comparative  anatomy." 
Panizza}  has  undertaken  an  experimental  in- 
vestigation into  the  functions  of  the  nerve,  and 
obtained  very  unexpected  results. 

From  these  we  are  led  to  believe  that  when 
this  nerve  is  pricked  in  a  living  animal,  this  is 
attended  by  no  indications  of  suffering  and  no 
convulsive  movements ;  that  section  of  both 
nerves  is  followed  by  loss  of  taste,  while  the 
tactile  sensibility  of  the  tongue  and  the  mus- 
cular movements  of  deglutition  and  mastication 
remain  unimpaired ;  that  section  of  the  fifth 
pair  is  on  the  contrary  followed  by  loss  of 
common  sensation  without  any  apparent  effect 
upon  the  taste.  From  these  and  other  experi- 
ments upon  the  nerves  supplying  the  tongue, 
he  concludes  that  the  glosso-pharyngeal  is  the 
nerve  upon  which  the  sense  of  taste  depends, 
and  is  therefore  the  true  gustatory  nerve.  Dr, 
M.  Hall  and  the  late  Mr.  Broughton§  had, 
from  experiments  performed  previous  to  the 
publication  of  those  of  Panizza,  arrived  at  the 
conclusion  that  this  nerve  is  not  a  nerve  of  com<- 
mon  sensation.  These  gentlemen  likewise 
reported  at  the  meeting  of  the  British  As-< 
sociation  for  1836  an  experiment,  the  results 
of  which  were  in  exact  accordance  with  those 
obtained  by  Panizza  upon  this  nerve,  but  no 
details  of  these  experiments  have  yet  been  pub- 


*  Anatomical  and  Physiological  Commentaries, 
n.  ii.  p.  11.  1822. 

+  London  Medical  and  Physical  Journal, vol.  xlix. 
1823. 

X  Edinburgh  Medical  and  Surgical  Journal,  Jan. 
1836,  and  Medical  Gazette,  Sept.  1835. 

§  Fourth  Report  of  British  Scientific  Association, 
and  Mr.  Broughton,  in  vol.  xlv.  of  Edinburgh  Me- 
dical and  Surgical  Journal. 


lished.  Mr.  Mayo*  has  stated  several  objec- 
tions to  these  conclusions  of  Panizza.  He  rests 
his  grounds  of  dissent  principally  upon  the 
fact  that  the  distribution  of  this  nerve  is  con- 
fined to  the  posterior  part  of  the  tongue ;  while 
the  sense  of  taste,  he  maintains,  is  also  present  in 
the  anterior  part  of  that  organ,  and  consequently 
it  cannot,  in  that  part  at  least,  depend  upon  the 
glosso-pharyngeal.  The  persistence  of  the  sense 
of  taste  after  section  of  the  fifth  pair  may,  Mr. 
Mayo  supposes,  depend  upon  the  palatine  twigs 
of  the  second  branch  of  the  fifth  pair  distri- 
buted upon  the  palate  and  isthmus  of  the  fauces. 
Mr.  Mayo  attempted  to  decide  the  matter  by 
experiment,  but  he  did  not  carry  this  suffi- 
ciently far  to  obtain  any  satisfactory  results. 
Dr.  Alcockf  has  also  lately  examined  into  the 
functions  of  this  nerve  experimentally,  and  has 
arrived  at  conclusions  at  direct  variance  with 
those  of  Panizza;  for  according  to  Dr.  Alcock, 
when  this  nerve  is  exposed  and  irritated  in  the 
living  animal,  it  excites  pain  and  spasmodic 
contractions  of  the  pharynx  and  muscles  of  the 
throat.  When  divided  on  both  sides,  the  ani- 
mal's taste,  "  to  say  the  least  of  it,  did  not  ap- 
pear to  be  much  affected."  He  believes  that  the 
sense  of  taste  enjoys  "  two  media  of  percep- 
tion, and  that  these  are  the  glosso-pharyngeal 
nerve  and  the  lingual  and  palatine  branches  of 
the  fifth."  He  also  states  that  the  muscular 
movements  of  deglutition  are  very  much  im- 
paired after  section  of  the  nerve  on  both  sides. 
He  concludes,  then,  that  the  glosso-pharyngeal 
are  sentient  nerves,  and  also  influence  muscular 
motion.  He,  however,  is  doubtful  in  what 
manner  these  muscular  movements  are  excited 
by  irritation  of  this  nerve,  for  though  "  dis- 
posed to  regard  the  result  in  question  as  the 
effect  of  a  sentient  impression  excited  through 
the  nerve,  and  referred  to  the  interior  of  the 
pharynx,"  from  the  fact  that  this  movement  ex- 
tends to  muscles  not  supplied  by  this  nerve, 
and  forms  an  associated  movement,  he  admits 
"  that  the  circumstance  may  be  as  well  ex- 
plained by  an  exalted  degree  of  muscular 
excitement,  or  by  a  higher  one  than  that  ne- 
cessary to  produce  the  simple  starting."  Pro- 
fessor Miilier  J  believes  that  an  examination  of 
the  position  of  the  ganglion  jugulare  will  de- 
cide that  the  glosso-pharyngeal  is  a  mixed 
nerve,  and  he  maintains  that  the  distribution  of 
this  nerve,  partly  for  sensation  (mucous  mem- 
brane of  the  root  of  tongue),  partly  for  the 
movements  of  muscles  (stylo-pharyngeus  and 
pharynx),  exactly  resembles  that  of  the  two 
roots  of  the  nervus  trigeminus.  Unable  amidst 
these  discordant  statements  to  come  to  any  sa- 
tisfactory conclusions  upon  the  proper  func- 
tions of  this  nerve,  I  entered  into  a  lengthened 
experimental  and  anatomical  investigation  for 
this  purpose.  The  experiments  were  twenty- 
seven  in  number,  and  were  performed  upon  as 

*  Medical  Gazette,  Oct.  1835,  and  4th  edit,  of 
Outlines  of  Physiology,  p.  314. 

f  Dublin  Journal  of  Chemical  and  Medical  Sci- 
ence, Nov.  1836. 

X  Archiv  fiir  Anat.  und  Physiol,  etc.  n.  ii. 
1837,  p.  276. 


GLOSSO-PHARYNGEAL  NERVE. 


499 


many  different  dogs.  Seventeen  of  these  were 
upon  the  living  animal,  with  the  view  of  as- 
certaining if  this  nerve  were  to  be  considered 
both  a  nerve  of  sensation  and  motion,  and  what 
are  the  effects  of  its  section  upon  the  associated 
movements  of  deglutition,  and  on  the  sense  of 
taste.  The  other  ten  were  performed  on  ani- 
mals immediately  after  they  had  been  deprived 
of  sensation,  for  the  purpose  of  satisfying  my- 
self to  what  extent  it  was  to  be  considered  a 
motor  nerve.  The  most  remarkable  effect  wit- 
nessed in  these  experiments  was  an  extensive 
convulsive  movement  of  the  muscles  of  the 
throat  and  lower  part  of  the  face  on  irritating 
this  nerve  in  the  living  animal,  provided  the 
irritation  was  applied  to  the  trunk  of  the  nerve 
before  it  had  given  off  its  pharyngeal  branches, 
or  to  one  of  these  pharyngeal  branches  sepa- 
rately. These  movements  were  equally  well 
marked  upon  pinching  the  cranial  end  of  the 
cut  nerve  after  it  had  been  divided  at  its  exit 
from  the  foramen  lacerum,  as  when  the  trunk 
of  the  nerve  and  all  its  branches  were  entire. 
In  some  of  these  experiments  we  observed  a 
remarkable  difference  between  the  effects  of  irri- 
tating this  nerve  before  and  after  it  had  given  off 
its  pharyngeal  branches,  which  is  valuable  on 
this  account,  that  it  may  explain  the  discrepan- 
cies between  the  results  obtained  by  Panizza, 
Dr.  M.  Hall,  and  the  late  Mr.  Broughton  on 
the  one  hand,  and  Dr.  Alcock  on  the  other. 
For  though  I  do  not  mean  to  affirm  that  pinch- 
ing the  lingual  portion  of  the  nerve  is  never 
followed  by  indications  of  suffering,  (for  from 
the  irregularity  in  the  origin  of  the  pharyngeal 
twigs,  and  the  difficulty  of  judging  at  the 
bottom  of  a  deep  wound  in  the  living  animal 
at  what  particular  part  these  are  all  given  off,  it 
is  generally  impossible  to  decide  where  the 
lingual  portion  may  be  said  to  begin,)  yet  I 
have  no  hesitation  in  saying  that  if  in  several 
of  these  experiments  we  had  operated  only  on 
that  portion  of  the  nerve  which  first  presented 
itself,  and  not  proceeded  to  dissect  it  back- 
wards towards  its  place  of  exit  from  the  cra- 
nium, we  should  have  gone  away  with  the 
impression  that  the  irritation  of  this  nerve  was 
followed  by  no  convulsive  movements,  and 
little  if  any  indications  of  suffering. 

From  a  review  of  all  the  experiments  which 
I  have  performed  upon  the  glosso-pharyngeal 
nerves,  I  am  inclined  to  draw  the  following 
conclusions :  — 

1.  That  this  is  a  nerve  of  common  sensation, 
as  indicated  by  the  unequivocal  expression  of 
pain  by  the  animal,  when  the  nerve  is  pricked, 
pinched,  or  cut. 

2.  That  mechanical  or  chemical  irritation 
of  this  nerve  before  it  has  given  off  its  pha- 
ryngeal branches,  or  of  any  of  these  branches 
individually,  is  followed  by  extensive  muscular 
movements  of  the  throat  and  lower  part  of  the 
face. 

3.  That  the  muscular  movements  thus  ex- 
cited depend,  not  upon  any  influence  extending 
downwards  along  the  branches  of  the  nerve  to 
the  muscles  moved,  but  upon  a  reflex  action 
transmitted  through  the  central  organs  of  the 
nervous  system. 


4.  That  these  pharyngeal  branches  of  the 
glosso-pharyngeal  nerve  possess  endowments 
connected  with  the  peculiar  sensations  of  the 
mucous  membrane  upon  which  they  are  distri- 
buted, though  we  cannot  pretend  to  say  posi- 
tively in  what  these  consist. 

5.  That  this  cannot  be  the  sole  nerve  upon 
which  all  these  sensations  depend,  since  the 
perfect  division  of  the  trunk  of  the  nerve  on 
both  sides  does  not  interfere  with  the  perfect 
performance  of  the  function  of  deglutition. 

6.  That  mechanical  or  chemical  irritation 
of  the  nerve,  immediately  after  the  animal  has 
been  killed,  is  not  followed  by  any  muscular 
movements  when  sufficient  care  is  taken  to  in- 
sulate it  from  the  pharyngeal  branch  of  the  par 
vagum.  And  we  here  observe  an  important 
difference  between  the  movements  excited  by 
irritation  of  the  glosso-pharyngeal  and  those  of 
a  motor  nerve,  for  while  the  movements  pro- 
duced by  the  irritation  of  the  glosso-pharyngeal 
are  arrested  as  soon  as  the  functions  of  the 
central  organs  of  the  nervous  system  have 
ceased,  those  from  irritation  of  a  motor  nerve 
such  as  the  pharyngeal  branch  of  the  par 
vagum,  continue  for  some  time  after  this,  and 
when  all  connexion  between  it  and  the  medulla 
oblongata  has  been  cut  off  by  the  section  of 
the  nerve. 

7.  That  the  sense  of  taste  is  sufficiently 
acute,  after  perfect  section  of  the  nerve  on  both 
sides,  to  enable  the  animal  readily  to  recog- 
nize bitter  substances. 

8.  That  it  probably  may  participate  with 
other  nerves  in  the  performance  of  the  function 
of  taste,  but  it  certainly  is  not  the  special  nerve 
of  that  sense. 

The  sense  of  thirst  which  is  referred  to  the 
fauces  and  pharynx  does  not  appear  to  de- 
pend entirely  upon  the  presence  of  this  nerve. 
The  animals  in  which  it  was  divided  lapped 
water  of  their  own  accord.  I  observed  one  of 
those  in  which  the  nerves  were  found  satisfac- 
torily divided,  rise,  though  feeble,  walk  up  (o 
a  dish  containing  water,  lap  some  of  it,  and 
return  again  to  the  straw  upon  which  he  was 
previously  lying. 

In  all  experiments  upon  the  glosso-pharyn- 
geal nerve  in  the  dog,  too  great  care  cannot  be 
taken  to  avoid  the  pharyngeal  branch  of  the 
par  vagum,  which  is  sometimes  situated  in  im- 
mediate contact  with  it,  at  other  times  one  or 
two  lines  below  it,  and  is  frequently  united  to 
it  by  a  considerable  communicating  branch,  so 
that  it  may  readily  be  mistaken  for  a  large  pha- 
ryngeal branch  of  the  glosso-pharyngeal.  This 
precaution  is  the  more  necessary,  as  I  am  con- 
fident that  these  two  nerves  differ  from  each 
other  in  function,  and  this  must  consequently 
seriously  affect  the  results.  I  attribute  the  dif- 
ficulty of  deglutition  after  section  of  this  nerve 
in  the  living  animal,  and  the  muscular  move- 
ments on  irritating  it  in  the  animal  recently 
killed,  observed  by  two  of  the  preceding  ex- 
perimenters, to  a  want  of  sufficient  precaution  irf 
separating  these  nerves  from  each  other.  These 
results  were  only  observed  by  me  when  the 
pharyngeal  branch  of  the  par  vagum  was  im- 
plicated in  the  experiment. 

2  L  2 


509 


GLUTEAL  REGION. 


With  regard  to  the  argument  in  favour  of 
the  motal  properties  of  this  nerve,  drawn  by 
Muller  from  its  anatomy,  it  appears  to  me  that 
this  analogical  mode  of  investigation,  valuable 
though  it  is,  must  be  permitted  to  yield  to  the 
more  positive  observations  obtained  from  expe- 
riment. And  though  it  may  be  granted  that 
the  apparent  limitation  of  the  ganglion  jugu- 
lare  to  the  posterior  filaments  of  this  nerve 
causes  it  here  to  resemble  closely  the  double 
roots  of  the  spinal  nerves,  yet  we  must  be 
wary  in  drawing  analogies  between  the  glosso- 
pharyngeal and  spinal  nerves,  since  we  have 
another  ganglion  situated  immediately  below 
this,  viz.  the  ganglion  petrosum,  which  involves 
the  whole  of  the  nerve,  and  to  this  assuredly 
we  have  no  analogical  structure  in  the  spinal 
nerves.  No  doubt  Miiller  supposes  that  this 
inferior  ganglion  differs  from  those  placed  upon 
the  posterior  roots  of  the  spinal  nerves,  and 
that  it.  belongs  to  the  sympathetic  system.  But 
as  nothing  like  conclusive  proof  is  advanced 
in  support  of  this  opinion,  we  may  in  the  mean 
time  reasonably  suspend  our  belief  as  to  the 
probable  influence  which  this  lower  ganglion 
may  exert  upon  the  functions  of  the  nerve. 

Of  course  the  fact  that  some  of  the  filaments 
of  the  glosso-pharyngeal  terminate  in  the  mus- 
cular fibre,  is  no  proof  that  these  filaments  are 
motal,  for  the  muscular  bundles  have  their  sen- 
sitive as  well  as  their  motal  filaments. 

(John  Reid.) 

GLUTEAL  REGION,  (Surgical  Anatomy.) 
(Fr.  region  fessiere.)  The  gluta?al  region  may 
be  defined  with  tolerable  precision  to  be  all  that 
space  external  to  the  pelvis  which  is  covered 
by  the  glutaei  muscles  of  each  side.  Its  boun- 
daries seem  naturally  to  be  the  crista  of  the 
ilium  above;  behind,  the  mesian  line  as  low 
down  as  the  point  of  the  coccyx  ;  before,  a  line 
drawn  from  the  anterior  superior  spinous  pro- 
cess of  the  ilium  to  the  trochanter  major;  and 
below,  a  line  drawn  from  the  point  of  the 
coccyx  to  the  insertion  of  the  glutaeus  maximus; 
in  fact,  the  inferior  margin  of  this  muscle  forms 
the  boundary  line.  These  limits,  better  defined 
than  those  of  most  of  the  anatomical  regions, 
separate  this  tract  from  the  lumbar  and  iliac 
regions  above,  from  the  superior  anterior  region 
of  the  thigh  in  front,  from  the  perineal  and 
posterior  regions  of  the  thigh  below,  and  from 
the  corresponding  part  of  the  opposite  side  at 
the  posterior  mesian  line.  This  space,  which 
does  not  comprise  many  points  of  importance 
in  surgical  anatomy,  is  yet  not  without  interest. 
Here  are  the  glutseal  and  ischiadic  arteries,  also 
the  commencement  of  the  course  of  the  great 
sciatic  nerve.  The  internal  pudic  artery  also 
skirts  along  the  inferior  edge  of  the  gluteal 
region,  but  this  will  be  best  considered  as  part 
of  the  region  of  the  perineum. 

The  first  thing  that  strikes  us  in  the  exami- 
nation of  this  region  is  the  great  density  and 
thickness  of  the  integuments ;  they  are  inferior 
in  this  respect  only  to  the  sole  of  the  foot. 
This  density  is,  however,  found  greater  pro- 
portionally in  the  true  skin  than  in  the  cuticle, 
which  retains  much  of  the  softness  and  pliabi- 


lity of  the  same  covering  in  other  parts  of  the 
body,  and  the  end  of  this  is  evident,  since 
whatever  the  pressure  may  be  upon  the  gluttsal 
parts,  a  dense  state  of  the  cuticle  in  any  degree 
similar  to  the  sole  of  the  foot  would,  in  the 
varied  positions  and  movements  of  the  trunk, 
be  quite  incompatible  with  comfort.  On  the 
other  hand,  the  true  skin,  though  pliant,  is 
remarkably  dense  and  strong,  its  fibres  almost 
tendinous  in  structure,  interlacing  each  other 
in  every  direction,  and  united  underneath  to  a 
strong  but  rather  loose  cellular  tissue  which 
connects  it  to  the  gluteus  muscle.  It  is  to  the 
laxity  of  this  cellular  connexion  that  the  inte- 
guments of  this  part  are  partly  indebted  for 
that  pliability  which  enables  us  to  rest  with 
ease  and  comfort  upon  surfaces  of  various 
degrees  of  hardness  and  inequality.  It  contains 
a  considerable  quantity  of  fat,  which  adds  to 
the  softness  and  elasticity  of  this  cushion,  and 
is  very  different  from  the  granular  hard  fat 
found  in  the  plantar  region.  The  density  of 
the  integumental  covering  of  the  gluteal  region 
varies  somewhat  in  different  parts.  It  is  greatest 
where  it  covers  the  tuber  ischii,  and  gradually 
diminishes  on  all  sides  except  on  the  side  next 
the  perineum,  where  the  change  is  very  abrupt 
from  its  characteristic  density  to  the  extreme 
thinness  and  delicacy  of  the  perineal  covering. 
The  peculiarity  of  structure  of  the  integument 
covering  the  glutaei  should  be  borne  in  mind 
by  the  surgeon  in  the  treatment  of  diseases  of 
this  part.  Abscesses  should  on  this  account 
be  earlier  opened  from  the  obstacle  thus  pre- 
sented to  their  pointing.  It  is  on  this  account 
also,  probably,  that  we  so  generally  find 
abscesses  here  accompanied  with  sloughing  of 
the  cellular  tissue,  which  is  best,  obviated  by  an 
early  opening. 

The  fleshy  fibres  of  the  gluteus  maximus 
are  covered  by  a  somewhat  denser  stratum  of 
cellular  tissue,  forming  an  aponeurosis  distinct 
from  the  fascia  lata  of  the  thigh,  though  conti- 
nuous with  it  at  the  anterior  edge  of  the  muscle, 
where  the  fascia  lata  lies  upon  the  anterior  half 
of  the  glutaeus  medius.  The  great  glutaeus  is 
composed  of  coarse  and  loosely  connected 
fasciculi,  running  in  a  direction  downwards 
and  forwards.  It  commences  by  a  somewhat 
semicircular  line  of  origin  from  the  posterior 
two-thirds  of  the  crista  ilii,  from  the  side  of  the 
sacrum  and  of  the  coccyx.  From  this  origin 
the  fibres  run  somewhat  converging  towards 
the  great  trochanter  and  upper  pait  of  the 
linea  aspera.  This  direction  of  the  fibres 
should  be  borne  in  mind  in  connexion  with  all 
remedial  manipulations  on  this  part,  that  the 
position  in  which  the  limb  should  be  placed 
may  be  chosen  most  favourably  for  the  relaxing 
of  the  muscle.  The  other  muscles  which  are 
in  this  neighbourhood,  and  all  of  which  move 
the  thigh-bone,  are  so  much  smaller  than  this 
great  muscle  that  the  relaxing  of  this  is  of  the 
first  importance,  and  the  position  must  be 
chosen  with  reference  almost  entirely  to  this. 

On  reflecting  the  glutseus  maximus  the  fol- 
lowing parts  are  brought  into  view : —  1st,  several 
large  branches  of  arteries  and  veins,  which  were 
divided  m  reflecting  the  muscle,  and  which 


GLUTEAL  REGION. 


501 


passed  into  the  substance  of  the  great  gluteus 
muscle;  these  are  from  the  gluteal  and  ischiatic 
arteries,  and  appear  principally  at  the  upper 
and  posterior  part  of  the  gluteus  medius; 
2d,  the  whole  of  the  gluteus  medius,  the  pos- 
terior two-thirds  of  which  had  been  covered  by 
the  larger  muscle;  3d,  at  the  posterior  edge  of 
the  gluteus  medius  is  thepyriformis  muscle  part- 
ly concealed  by  it,  and  coming  out  of  the  supe- 
rior sacro-sciatic  foramen  ;  4th,  next  below  the 
piriformis  lie  the  two  gemelli,  with  the  tendon 
of  the  obturator  internus  between  them,  and 
below  these  is  the  quadratus  femoris,  having 
underneath  it  the  strong  tendon  of  the  obturator 
externus;  5th,  the  great  sciatic  nerve  is  seen 
emerging  from  the  superior  sacro-sciatic  fora- 
men near  the  sciatic  artery.  Sometimes  it 
comes  out  entirely  below  the  piriformis;  some- 
times it  descends  in  two  branches,  one  of  which 
peiforates  that  muscle,  and  they  then  unite. 
The  trunk  passes  directly  downwards,  cross- 
ing the  rotator  muscles  of  the  hip,  and  pass- 
ing between  the  projecting  tuberosity  of  the 
ischium  and  the  trochanter  major.  In  this 
part  of  its  course  it  is  accompanied  by  the 
sciatic  artery,  which  is  seen  about  half  an  inch 
to  the  internal  or  sacral  side  of  the  nerve,  and 
sends  one  considerable  branch  to  supply  the 
nerve,  and  runs  tortuously  imbedded  in  its 
iieuri'.ema.  The  course  which  the  nerve  and 
artery  here  take  will  be  represented  by  a  line 
drawn  from  the  posterior  superior  spinous  pro- 
cess of  the  ilium  to  a  spot  midway  between 
the  tuber  ischii  and  trochanter  major.  Lastly, 
in  this  view  are  exposed  the  bursal  sacs,  of 
which  there  are  several  between  the  gluteus 
maxim  us  and  the  subjacent  parts.  The  most 
considerable  is  found  between  it  and  the  external 
surface  of  the  trochanter  major.  A  consider- 
able but  smaller  one  is  placed  between  its  broad 
tendinous  expansion  and  the  upper  part  of  the 
vastus  externus,  and  two  smaller  ones  com- 
monly between  the  muscle  and  the  os  femoris 
at  the  upper  and  back  part  of  the  thigh.  The 
ischiatic  artery  at  the  commencement  of  its 
course  is  smaller  than  the  gluteal,  and  comes 
down  over  the  pyriformis  muscle,  and  makes 
its  exit  from  the  pelvis  through  the  lower  part 
of  the  sciatic  notch,  between  the  pyriform  and 
levator  ani  muscles,  above  the  lesser  sciatic 
ligament,  and  in  front  of  the  sciatic  nerve ;  it 
sometimes  passes  between  the  roots  of  this 
nerve.  On  the  dorsum  of  the  pelvis  the  sciatic 
artery  is  covered  by  the  gluteus  maximus 
muscle,  and  may  be  seen  by  a  similar  dissec- 
tion to  that  which  exposes  the  gluteal  artery, 
excepting  that  it  is  found  about  an  inch  and  a 
half  lower  down  than  the  last-named  vessel. 

The  gluteal  artery  comes  out  of  the  pelvis 
at  the  upper  part  of  the  sciatic  notch  in  com- 
pany with  the  superior  gluteal  nerve  and  vein. 
It  immediately  winds  upwards  upon  the  dorsum 
ilii,  keeping  close  to  the  bone,  and  shortly 
after  its  arrival  upon  the  dorsum  it  divides  into 
branches  principally  distributed  to  the  gluteal 
muscles.  To  expose  this  artery  and  its  branches 
in  dissection,  it  is  necessary  to  proceed  as  in 
the  dissection  of  the  gluteus  maximus  muscle. 


Next  divide  this  muscle  in  a  line  from  the 
posterior  superior  spine  of  the  ilium  to  the 
tuberosity  of  the  ischium.  In  making  this  dis- 
section several  large  arteries  and  veins  must  be 
injured.  If  the  edges  of  the  muscle  be  now- 
separated  and  the  subjacent  cellular  membrane 
removed,  the  gluteal  artery,  accompanied  by 
one  or  two  large  veins  and  by  the  gluteal  nerve, 
may  be  seen  escaping  from  the  sciatic  notch 
above  the  pyriform  muscle,  between  it  and  the 
gluteus  medius.  This  artery,  as  it  escapes  from 
the  pelvis,  lies  three  inches  and  a  half  from  the 
mesian  line,  or  from  the  spinous  processes  of 
the  sacrum. 

The  gluteal  and  ischiadic  arteries,  as  we  have 
seen,  are  covered  by  the  gluteus  maximus  mus- 
cle, and  lie  at  such  a  depth  from  the  surface 
that  they  are  not  very  liable  to  injury.  Wounds, 
however,  of  this  part  do  occasionally  implicate 
these  vessels,  either  in  their  large  branches  or 
even  the  trunks  themselves,  and  they  have  been 
affected  with  aneurism,  an  instance  of  which 
is  mentioned  by  Mr.  J.  Bell,*  and  which 
attained  a  considerable  size.  In  the  case  of  a 
wound,  its  direction  will  lead  us  to  the 
situation  of  the  artery ;  and  in  the  instance  of 
aneurism  just  mentioned,  Mr.  Bell  ventured  to 
lay  open  the  sac  and  thus  reach  the  mouth  of 
the  gluteal  artery,  which  he  secured  by  liga- 
ture, and  this  perhaps  might  be  accomplished 
in  a  very  emaciated  person;  but  generally 
speaking  the  artery  lies  so  deep,  and  the  vessels 
which  must  be  wounded  in  rhak  ing  the  neces- 
sary incisions  would  by  their  bleeding  so  ob- 
scure the  operation,  that  the  most  experienced 
surgeons  do  not  recommend  the  attempt  under 
ordinary  circumstances,  but  prefer  the  operation 
of  tying  the  internal  iliac.f  As  a  guide,  how- 
ever, to  the  situation  of  the  gluteal  artery, 
whether  in  the  examination  of  a  wound  or  in 
operating  upon  it,  its  position  on  the  dorsum 
of  the  pelvis  may  be  ascertained  by  drawing  a 
line  from  the  posterior  spinous  process  of  the 
ilium  to  the  middle  of  the  space  between  the 
tuberosity  of  the  ischium  and  trochanter  major. 
If  this  line  is  divided  into  three,  the  gluteal 
artery  will  be  found  emerging  from  the  pelvis 
at  the  juncture  of  its  upper  and  middle  thirds.! 

To  return  to  the  consideration  of  the  anato- 
mical structures  which  we  expose  in  succession. 
We  are  struck  with  the  difference  in  texture  of 
the  three  glutei  muscles.  The  fibres  of  the 
two  smaller  glutei  are  of  moderate  size  and 
strength,  while  those  of  the  larger  gluteus  are 
remarkable  for  their  coarseness  and  large  dimen- 
sions. The  relative  situation  of  the  three 
muscles  is  also  important.  The  position  and 
direction  of  the  gluteus  maximus  is  just  in 
that  line  in  which  the  greatest  vigour  of  action 
is  required  to  erect  the  body  by  drawing  the 
back  part  of  the  pelvis  towards  the  trochanter 
major.  In  this  operation  it  is  assisted  by  the 
position  of  the  gluteus  medius  and  minimus, 

*  Principles  of  Surgery,  vol.  i.  p.  421. 

f  See  Med.  Chir.  Trans,  vol.  v.  Also  Guthrie  on 
Diseases  of  Arteries,  p.  364. 

}  See  Harrison's  Surgical  Anatomy  of  the  Arte- 
ries, vol.  ii.  p.  1U0. 


502 


GLUTEAL  REGION. 


the  posterior  fibres  of  which  are  covered  by  the 
gluteus  maximus.  These  anterior  fibres  have  a 
different  action,  varying  in  the  different  posi- 
tions of  the  body  in  relation  to  the  thigh,  and, 
according  to  this,  consisting  either  in  rotation 
inwards,  abduction,  or  flexion  of  the  femur,  or, 
this  bone  being  fixed,  assisting  in  the  various 
anterior  movements  of  the  pelvis  upon  the  thigh. 

At  the  posterior  edge  of  the  middle  gluteus 
is  the  pynformis  coming  out  of  the  upper  open- 
ing of  the  sciatic  notch.  Here,  as  we  have 
seen,  the  gluteal  artery  is  also  emerging  from 
the  pelvis  and  winding  round  the  upper  edge 
of  the  notch.  This,  therefore,  will  be  the  situa- 
tion of  an  aneurism  of  this  artery,  and  a  pul- 
sating tumour  being  detected  in  the  situation 
just  indicated  by  measure,  as  the  seat  of  this 
vessel,  will  be  a  very  strong  ground  for  deciding 
both  as  to  the  disease  and  the  vessel  diseased. 
A  case  lately  came  under  our  notice  of  a  very 
obscure  character  in  which  a  swelling  was 
situated  precisely,  in  the  position  of  the  gluteal 
artery,  but  without  pulsation  or  any  other  sym- 
ptom of  aneurism.  The  swelling  was  at  first 
indistinct,  but  as  the  surrounding  parts  wasted 
under  the  effect  of  disease  it  became  more  pro- 
minent. It  was  firm  to  the  touch  and  rather 
moveable,  and  about  the  size  of  a  hen's  egg. 
But  the  principal  part  of  the  disease  showed 
itself  within  the  pelvis  in  a  tumour  consisting 
almost  entirely  of  coagulum,  as  was  proved  by 
puncture,  situated  behind  the  rectum,  and 
pressing  it  forward  so  as  to  occupy  nearly  the 
whole  pelvis,  and  obstructing  the  passage  both 
of  faeces  and  urine.  As  there  was  no  decided 
symptom  of  aneurism  no  operation  was  at- 
tempted for  the  relief  of  the  case,  and  as  the 
girl,  who  is  eighteen  years  of  age,  still  lingers, 
the  nature  of  the  disease  is  not  yet  cleared  up. 
But  this  part  also  occasionally  gives  exit  to  a 
hernial  tumour,  part  of  the  intestines  or  even 
the  bladder  or  ovary  becoming  thus  displaced 
and  being  lodged  in  the  sac*  The  superior 
opening  of  the  sciatic  notch  is  bounded  above 
by  the  notch  of  the  ilium,  before  by  the  de- 
scending ramus  of  the  ischium,  and  below  and 
behind  by  the  superior  sacro-sciatic  ligament; 
and  so  large  is  the  opening  thus  left  that  we 
might  expect  to  find  the  protrusion  of  some  of 
the  viscera  of  the  pelvis  much  more  frequently 
than  we  do.  Yet  so  completely  is  this  part 
covered  and  defended  by  the  pyriform  muscle, 
the  plexus  of  nerves,  the  glutei  maximus  and 
medius,  that  this  form  of  hernia  is  an  extremely 
rare  occurrence.  When  it  does  occur  in  the  adult, 
the  diagnosis  is  very  difficult  while  the  hernia  is 
small,  owing  to  the  great  depth  at  which  it  is 
situated.  When,  however,  it  is  congenital,  the 
nature  of  the  swelling  is  larger  in  proportion  to 
the  size  of  the  surrounding  parts,  and  the  depth 
of  the  superjacent  parts  less  ;  yet  even  here 
Professor  Schreger  did  not  at  first  detect  the 
nature  of  the  swelling.  In  fact  nothing  but 
the  actual  feeling  of  the  guggling  of  the  gas  of 
the  intestines  under  the  finger  seems  sufficient 

*  See  a  summary  of  cases  of  ischiatic  hernia  in 
Cooper's  Fint  Lines  of  Surgery. 


to  discriminate  the  case,  and  this  is  of  course 
not  to  be  expected  when  the  gut  is  strangulated. 
Indeed,  in  Dr.  Jones's  case*  the  symptoms 
were  not  at  all  referred  by  the  patient  to  the 
true  seat  of  the  disease,  and  the  surgeon  was 
in  consequence  never  led  to  make  any  external 
examination  of  this  part.  It  may  be  well  to 
state  here  the  anatomical  relations  of  the  hernial 
sac  in  this  case,  which  was  carefully  dissected. 
"  A  small  orifice  in  the  side  of  the  pelvis, 
anterior  to  but  a  little  above  the  sciatic  nerve 
and  on  the  fore  part  of  the  pyriformis  muscle, 
led  into  a  bag  situated  under  the  gluteus  maxi- 
mus muscle,  and  this  was  the  hernial  sac,  in 
which  the  portion  of  intestine  had  been  stran- 
gulated. The  cellular  membrane  which  con- 
nects the  sciatic  nerve  to  the  surrounding  parts 
of  the  ischiatic  notch  had  yielded  to  the  pres- 
sure of  the  peritoneum  and  viscera.  The  orifice 
of  the  hernial  sac  was  placed  anterior  to  the 
internal  iliac  artery  and  vein,  below  the  obtura- 
tor artery  and  above  the  obturator  vein.  Its 
neck  was  situated  anterior  to  the  sciatic  nerve, 
and  its  fundus,  which  was  on  the  outer  part  of 
the  pelvis,  was  covered  by  the  gluteus  maxi- 
mus. Anterior  to  but  a  little  below  the  fundus 
of  the  sac,  was  situated  the  sciatic  nerve, 
behind  it  the  gluteal  artery.  Above,  it  was 
placed  near  the  bone,  and  below  appeared  the 
muscles  and  ligaments  of  the  pelvis." 

We  must  not  conclude  this  article  without 
a  few  words  on  the  general  form  of  the  gluteal 
region  as  affording  an  important  means  of 
diagnosis  in  disease.  In  examining  this  re- 
gion in  a  healthy  person  we  observe,  1st,  the 
thick  rounded  prominence  of  the  nates,  formed 
by  the  posterior  and  inferior  margin  of  the 
gluteus  maximus ;  2d,  the  projection  of  the 
trochanter  major,  only  covered  by  the  integu- 
ments and  the  thin  tendon  of  the  last-named 
muscle ;  3d,  the  projection  of  the  crista  ilii7 
forming  the  upper  boundary  of  the  region ; 
4th,  a  depression,  perpendicular  in  direction, 
between  the  nates  and  the  trochanter  major ; 
5th,  another  depression,  slighter  than  the  last 
and  transverse  in  direction,  between  the  tro- 
chanter and  crista  ilii. 

Now  almost  all  these  points  become  altered 
in  character  and  relation  in  disease.  In  dislo- 
cation of  the  femur  they  of  course  are  changed 
by  the  difference  in  position  which  the  trochan- 
ter assumes  in  common  with  the  head  of  the 
bone  ;  and  according  to  the  unnatural  situation 
which  this  occupies,  so  will  the  alteration  in 
the  general  form  of  the  parts  be  modified.  But 
we  now  speak  particularly  of  the  changes  of 
disease.  Even  in  the  inflammatory  stage  of 
disease  of  the  hip-joint,  it  is  surprising  how 
great  is  the  effect  produced  upon  the  nates. 
The  roundness  and  fulness  gradually  go,  the 
nates  looks  wasted,  and  the  depression  between 
this  and  the  trochanter  disappears.  This  wast- 
ing, arising  from  interstitial  absorption  of  the 
gluteus  and  parts  adjacent,  is  the  more  striking 
as  it  occurs  too  rapidly  upon  the  affection  of 
the  joint  to  be  the  effect  of  inaction  of  the 

*  See  Sir  A.  Cooper  on  Hernia,  part  ii.  p.  67. 


HiEMATOSINE. 


503 


muscle,  as  we  have  seen  it  occur  in  a  marked 
degree  in  a  rather  severe  attack  of  inflammation 
of  the  joint,  which  readily  yielded  to  treat- 
ment.* Then  in  the  more  advanced  stages  of 
disease  of  the  joint,  the  depressions  above 
mentioned  are  not  only  lost,  but  from  morbid 
depositions  in  the  neighbourhood  of  the  hip 
they  become  elevated  and  swollen,  and  the 
sharp  prominences  of  the  trochanter  lost  in  the 
general  fulness  of  the  part. 

(A.  T.  S.  Dodd.) 

GROIN,  REGION  OF  THE,  (Surgical 
Anatomy.)  (Fr.  Vaine,  region  inguinale.)  The 
limits  of  this  region,  as  understood  by  most 
surgical  writers,  seem  to  be  wholly  artificial. 
The  groin  constitutes  the  confines  of  the  ab- 
domen and  the  thigh ;  and  Poupart's  ligament 
forms  a  natural  line  of  division  between  its 
femoral  and  its  abdominal  portions.  A  line 
drawn  horizontally,  the  subject  being  erect, 
from  the  anterior  superior  spinous  process  of 
the  ilium  to  the  linea  alba,  forms  the  superior 
limit  of  this  region,  while  below  it  may  be 
defined  by  a  line  parallel  to  the  former  one, 
and  extending  from  the  pubis  to  the  outer  part 
of  the  thigh.  For  the  particulars  of  this  region, 
see  Hernia,  Femoral  Artery,  Abdomen, 
and  Thigh,  regions  of  the. 

(R.  B.  Todd.) 

H^MATOSINE,  (ai^a,  blood,  and  tt.ttto, 
to  fall.)  The  colouring  matter  of  the  biood.f 
This  principle  separates  with  the  fibrine  of  the 
blood  when  that  fluid  coagulates,  and  may  be 
obtained  free  from  adherent  albuminous  matter 
by  the  process  recommended  by  Berzelius, 
which  is  as  follows.  The  coagulum  is  first  to 
be  sliced  in  thin  pieces  with  a  sharp  knife,  and 
then  carefully  washed  in  separate  portions  of 
distilled  water;  by  these  means  we  separate 
the  adherent  serum,  and  if  the  washing  is 
gently  performed,  but  little  haematosine  be- 
comes washed  away  with  it.  The  slices  thus 
prepared  are  placed  on  a  filter  and  allowed  to 
drain  :  when  the  draining  is  complete,  the  slices 
are  to  be  thrown  into  a  glass  vessel  and  broken 
up  in  distilled  water ;  we  thus  procure  a  solution 
of  the  colouring  matter  while  any  fibrine  pre- 
sent gradually  subsides.  The  liquor  when 
poured  off  is  a  tolerably  pure  solution  of 
haematosine.  If  it  is  wished  to  procure  the 
principle  in  the  solid  form,  the  solution  may 
be  evaporated  at  a  temperature  not  exceeding 
100°  Fahrenheit. 

Engelhart  prefers  heating  the  solution  after 
filtration  to  about  150°  Fahrenheit,  which  deter- 
mines the  precipitation  of  the  haematosine, 
while  any  albumen  which  may  possibly  exist 

*  There  seems  to  be  a  law  of  the  animal  economy 
that  when  a  joint  is  diseased  the  muscles  moving  it 
immediately  lose  tone  and  bulk,  and  there  is  no 
more  marked  symptom  of  disease  of  an  articulation 
than  this  wasting  of  the  muscles  which  belong  to  it. 

t  Lecanu  considers  that  haematosine  is  a  com- 
pound of  albumen  with  a  substance  which  lie  be- 
lieves to  be  the  true  colouring  matter  of  the  blood, 
and  which  he  calls  Olobuline. 


in  solution  with  it,  remains  dissolved  at  that 
temperature.  Engelhart's  process  yields  us 
haematosine  in  its  purest  form,  but  when  thus 
obtained  it  is  no  longer  soluble  in  water, 
whereas,  if  procured  by  evaporation  at  100° 
Fahrenheit,  it  is  still  soluble,  and  what  is  very 
extraordinary,  dry  haematosine  procured  at  that 
temperature,  though  it  be  afterwards  subjected 
to  a  heat  of  212"  Fahrenheit,  does  not  lose  its 
property  of  dissolving  in  water.  Haematosine 
may  be  described  under  two  forms,  viz.  in 
solution  and  in  the  dry  state. 

The  aqueous  solution  of  hamatosine  is  pre- 
cipitated by  alcohol  and  the  acids.  The 
alkaline  hydro-sulphurets  and  sulphuretted  hy- 
drogen change  the  colour  of  the  solution  to 
green  ;  nearly  all  the  metallic  and  earthy  salts 
precipitate  it.  Infusion  of  galls  produces  a 
pale  red  precipitate;  gallic  acid,  however,  does 
not  show  this  effect.  Chlorine  passed  through 
a  solution  of  haematosine  decolorizes  it. 
Bromine  produces  a  similar  result,  but  it  is 
some  time  before  the  effect  is  observed.  Iodine 
will  also  decolorize  the  solution  after  some 
hours,  and  produces  a  brown  precipitate,  which 
is  found  to  contain  iodine. 

Haematosine  when  dry  is  of  a  dark  red  co- 
lour and  exceedingly  hard,  having  a  vitreous 
fracture.  Its  chemical  properties  in  many  re- 
spects resemble  those  of  fibrine,  and  albumen 
in  the  coagulated  state.  Berzelius  remarks 
that,  like  fibrine,  it  contains  a  fatty  matter  pe- 
culiar to  itself  which  can  be  separated  by  ether; 
this  is  one  point  of  resemblance  in  the  opinion 
of  that  chemist.  The  action  of  acetic  acid  on 
haematosine  is  a  very  striking  point  of  resem- 
blance between  that  body  and  fibrine ;  for 
when  the  acid  in  the  concentrated  state  is  al- 
lowed to  remain  in  contact  with  haematosine 
for  a  few  hours,  we  observe  that  it  is  converted 
into  a  tremulous  brown  mass  which  is  more  or 
less  soluble  in  water,  and  which  during  solu- 
tion evolves  nitrogen  gas.  The  nitric,  hydro- 
chloric, and  sulphuric  acids,  if  diluted  with  an 
equal  bulk  of  water,  and  digested  on  haema- 
tosine, become  coloured  yellow  and  disengage 
nitrogen ;  but  they  do  not  dissolve  the  prin- 
ciple even  at  a  boiling  heat.  The  results  of 
such  digestions,  however,  in  the  hydrochloric 
and  sulphuric  acids,  are  soluble  in  water;  but 
that  which  has  been  digested  in  nitric  acid 
remains  insoluble. 

Potash,  soda,  and  ammonia  dissolve  haema- 
tosine with  facility,  and  it  is  precipitated  from 
such  solution  by  the  addition  of  an  acid.  The 
acetic  acid  acts  thus,  but  re-dissolves  the  pre- 
cipitate if  added  in  excess,  as  it  would  albu- 
men or  fibrine. 

Tannin  precipitates  haematosine  from  solu- 
tion in  alkalies. 

Tiedemann  and  Gmelin  have  observed  that 
boiling  alcohol  will  dissolve  haematosine  ;  this 
is  also  the  case  to  a  considerable  extent  with 
its  combinations  with  several  of  the  acids  which 
precipitate  it.  When  haematosine  is  incinerated 
and  decarbonized,  it  yields  an  ash  amounting 
to  1.3  per  cent,  of  its  weight:  this,  according 
to  Berzelius,  is  composed  of  the  following  sub- 
stances : — 


504 


IJ/T.MATOSINE. 


Carbonate  of  soda,  with  traces 


of  phosphate    0.3 

Phosphate  of  lime    0.1 

Caustic  lime   0.2 

Subphosphate  of  iron   0.1 

Sesqui-oxide  of  iron    0.5 

Carbonic  acid  and  loss   0.1 


1.3 

The  ultimate  analysis  of  hoematosine  ap- 
proaches very  nearly  to  that  of  fibrine.  Mi- 
chael is  declares  to  have  found  a  difference  of 
ultimate  constitution  between  the  colouring 
matter  of  arterial  and  venous  blood  :  his  ana- 
lyses are  as  follows : — 


arterial.  v  enuii?. 

Nitrogen                  17.253  17.392 

Carbon                     51.382  53.231 

Hydrogen                  8.354  7.711 

Oxygen                   23.011  21.666 


It  will  be  observed,  on  examining  these  ana- 
lyses, that  the  difference  of  constitution  is  so 
small  that  we  may  reasonably  conclude  it  has 
been  produced  by  a  difference  in  manipulation 
or  some  other  extraneous  cause  capable  of 
modifying  the  result:  indeed,  ultimate  ana- 
lyses of  identical  substances  have,  when  in  the 
hands  of  different  chemists,  often  yielded  re- 
sults far  more  discrepant  than  these,  and  that 
too  when  each  operator  stood  high  as  an  ana- 
lyst. Berzelius,  in  remarking  on  these  expe- 
riments, observes  that  it  is  impossible  for  the 
chemist  to  fix  the  state  of  blood  whether  arterial 
or  venous;  for  it  will  lose  its  condition  with 
respect  to  the  colouring  matter  long  before  the 
chemist  can  procure  its  haematosine  for  analysis. 
Thus  the  venous  clot  becomes  of  a  bright  red 
colour  when  exposed  to  air,  and  arterial  blood 
soon  loses  its  vermilion  hue.  A  great  con- 
trariety of  opinion  exists  as  to  the  cause  of  the 
red  colour  of  hamatosine,  some  chemists  sup- 
posing that  the  iron  contained  in  it  takes  an 
active  part  in  its  coloration,  while  others 
maintain  that  though  iron  is  present  it  cannot 
be  considered  as  the  cause  of  colour.  Win- 
terl  imagined  he  had  discovered  the  secret 
when  he  formed  sulphocyanic  acid  (blutsaure) 
by  carbonizing  blood  with  carbonate  of  potash 
and  precipitated  salt  of  iron  with  the  lixivium — 
an  experiment  quoted  by  Treviranus ;  but  we 
are  unable  to  detect  the  sulphocyanic  acid  in 
blood,  so  this  formation  of  a  ferruginoifs  co- 
louring matter  must  not  be  considered  as  in 
any  way  assisting  in  the  inquiry,  although  it 
simulates  the  tint  of  blood  most  completely. 
Fourcroy  asserted  that  subphosphate  of  iron 
was  capable  of  imparting  a  red  colour  to  serum, 
which  is  not  the  case,  and  went  so  far  as  to 
declare  that  the  colourless  globules  of  the 
chyle  contained  neutral  phosphate  of  iron, 
which,  when  mixed  with  the  blood,  was  de- 
composed by  the  alkali  present  into  a  sub- 
phosphate, whicl)  on  reaching  the  lungs  be- 
came a  pei-salt  and  imparted  colour  to  the 
fluid.  This  idea  is  quite  hypothetical,  and  in 
discordance  with  facts  as  observed  by  other 
chemists. 


Engelhart's  experiments  on  hsematosine  tend 
to  shew  that  iron  is  in  some  way  influential 
in  producing  the  red  colour  of  the  blood.  He 
showed  that,  though  albumen  and  fibrine 
yielded  no  iron  on  incineration,  the  metal  ex- 
isted in  considerable  quantity  in  hasmatosine. 
He  found  that  a  solution  of  red  particles  im- 
precated with  sulphuretted  hydrot;en  became 
of  a  violet  colour  and  then  passed  to  a  green, 
it  being  impossible  to  restore  the  original  red 
tint.  Chlorine  when  passed  through  the  solution 
bleached  it,  having  previously  produced  a 
green  colour ;  when  decolorization  was  com- 
plete, white  flocculi  were  observed  to  fall, 
which  on  being  examined  yielded  no.  appre- 
ciable ash,  while  the  clear  solution  gave  evi- 
dence of  iron  by  the  usual  reagents.  The 
white  flocculi  were  supposed  by  Engelhart  to 
be  the  colouring  matter  changed  to  white  by 
the  abstraction  of  its  iron.  It  is  evident  that 
even  if  the  colour  of  the  blood  were  owing  to 
some  peculiar  animal  matter  and  not  to  iron, 
we  should  still  expect  decolorization  by  chlo- 
rine ;  but  yet  the  change  of  colour  from  red  to 
green  which  that  re-agent  produces  previous  to 
decolorizing  the  solution,  renders  it  probable 
that  its  action  is  on  iron  in  some  form  of  com- 
bination as  yet  unknown.  Rose  has  shown 
that  many  organic  matters  interfere  with  the 
action  of  the  tests  for  iron  when  present  in 
solution  with  that  metal,  and  quotes  this  to 
account  for  the  failures  in  procuring  the  re- 
actions of  iron  from  the  blood  in  a  fluid  state. 
Some  experiments  of  Berzelius,  however,  have 
proved  that  the  artificial  combinations  of  iron 
with  albumen  which  Rose  formed,  can  be  pre- 
cipitated by  ferrocyanate  of  potassa  if  they 
are  previously  treated  with  acetic  acid  :  as  this 
does  not  happen  with  blood,  it  is  very  pro- 
perly contended  that  Rose's  experiments  are 
not  to  be  looked  upon  as  an  explanation  of  the 
difficulty.  In  a  paper  published  by  Mr. 
Brande  in  the  Philosophical  Transactions  for 
1812,  that  gentleman  proposes  to  consider 
hsmatosine  as  an  animal  dye,  which  like  co- 
chineal is  capable  of  uniting  with  metallic 
oxides ;  thus  the  oxides  of  mercury  and  tin  are 
active  precipitants  of  this  colouring  matter, 
and  woollen  clothes  previously  impregnated 
with  a  solution  of  bichloride  of  mercury  have 
been  permanently  dyed  by  steeping  them  in  a 
solution  of  hsematosine.  The  question  as  to 
whether  or  not  iron  be  really  necessary  to  the 
existence  of  the  red  colour  of  the  blood  can- 
not be  considered  as  determined,  and  it  is 
difficult  to  imagine  any  line  of  experimenting 
which  could  afford  results  sufficiently  satis- 
factory to  settle  the  point.  Mr.  Brande's  ex- 
periments, by  which  he  concluded  that  haema- 
tosine  contained  iron  in  no  greater  proportion 
than  fibrine  or  albumen,  would  have  placed  the 
matter  beyond  doubt  if  other  chemists  had 
confirmed"  his  observations ;  but  the  expe- 
riments of  Dr.  Engelhart  published  in  1825, 
and  which  have  received  very  general  con- 
firmation, show  that  fibrine  and  albumen 
when  pure  contain  no  iron,  and  that  the  metal 
exists  in  considerable  quantity  in  hrcmatosine. 

(G.  0.  Rees.) 


BONES  OF  THE  HAND. 


505 


HAIR.    See  Tegumentaf.y  System. 

HAND,  BONES  OF  THE,  (Human  Ana- 
tomy.) The  hand  (veig,  wiaraws;  Hi.  la  main; 
Germ,  die  Hand,)  is  the  inferior  segment  of 
the  upper  extremity.  Its  presence  is  charac- 
teristic of  man  and  the  Quadrumana. 

Although  formed  on  the  same  general  type, 
the  hand  will  be  found  to  exhibit  many  points 
of  difference  from  the  foot — characters  strongly 
indicative  of  the  diversity  of  use  for  which  it 
is  designed.  In  examining  the  skeleton  of  the 
hand,  we  observe  subdivisions  analogous  to 
those  which  exist  in  the  foot — the  carpus  cor- 
responding to  the  tarsus,  the  metacarpus  to  the 
metatarsus,  and  the  phalanges  of  the  fingers  in 
every  way  analogous  to  those  of  the  toes. 
Independently  of  the  lightness  and  mobility 
which  are  such  prominent  features  in  the  me- 
chanism of  the  hand,  when  contrasted  with 
that  of  the  foot,  the  divergence  of  the  first  or 
radial  finger  ( the  thumb )  from  the  line  of 
direction  of  the  other  four,  is  peculiarly  cha- 
racteristic of  the  band.  Whilst  the  four  fingers, 
properly  so  called,  are  parallel  to  the  middle 
line  of  the  hand,  the  thumb,  when  extended, 
forms  with  itan  angle  of  rather  more  than  45°.  To 
this  position  of  the  thumb  is  due  in  the  greatest 
part  the  facility  of  opposing  it  to  one  of  the 
fingers,  a  movement  so  necessary  in  the  pre- 
hension of  minute  objects.* 

The  general  form  of  the  hand  i.s  oval,  the 
obtuse  extremity  corresponding  to  the  tips  of 
the  fingers,  the  unequal  lengths  of  which  oc- 
casion the  curvature  in  this  situation.  On  its 
posterior  surface  or  dorsum,  the  hand  is  convex  ; 
on  its  anterior  surface  or  palm,  it  is  concave  : 
both  these  surfaces  correspond  to,  and  in  the 
recent  state  are  supported  by,  the  bones  of  the 
carpus  and  metacarpus. 

I.  Carpus  (Germ,  die  Handivurzel).  The 
carpus  bears  a  much  less  proportion  in  size  to 
the  whole  hand  than  the  tarsus  does  to  the  foot ; 
it  forms  scarcely  more  than  one-fourth  of  the 
hand.  Its  outline  is  oval,  the  long  axis  being 
transverse :  if  examined  in  a  hand  to  which 
the  ligaments  are  attached,  the  carpus  will  be 
found  to  form  the  posterior  and  osseous  portion 
of  an  osseo-ligamentous  ring,  which  gives  pas- 
sage to  the  tendons  of  the  fingers.  It  is  con- 
sequently hollowed  from  side  to  side,  and  is 
bounded  on  each  side  by  a  bony  ridge,  which 
gives  attachment  to  the  ligament  ( annular 
ligament )  which  forms  the  anterior  part  of  the 
ring  ;  on  the  radial  side  the  ridge  is  formed  by 
a  process  of  the  os  trapezium  and  of  the  sca- 
phoid ;  on  the  ulnar,  where  there  is  a  more 
prominent  ridge,  by  a  process  of  the  unciform 
bone,  and  by  the  os  pisiforme. 

Seven  bones,  arranged  in  two  rows,  form 
the  carpus.  The  superior  row  consists  of  the 
os  navicu/ure,  as  lunare,  and  os  cuneiformc, 
to  which  last  is  articulated  a  bone,  constantly 
reckoned  as  a  carpal  bone,  but  which,  I  con- 
ceive, may  be  more  correctly  regarded  as  a 
sesamoid  bone,  the  us  pisiforme.    The  second 

*  See  the  prefatory  observations  to  the  article 
Foot. 


or  inferior  row  is  formed  by  the  os  trapezium, 
os  trupezoides,  os  magnum,  and  os  unciforme. 

1 .  Os  naviculare  (os  scuphoideum  ;  Fr.  le 
scaphotde ;  Germ,  das  Kahnbem).  The  na- 
vicular or  scaphoid  is  the  largest  of  the  upper 
row,  and  likewise  the  most  external.  Its  su- 
perior surface  is  convex,  oval,  with  long  axis 
transverse,  articular,  and  is  adapted  to  the 
outer  part  of  the  carpal  articular  extremity  of 
the  radius.  The  hollowed  surface,  to  which  it 
owes  its  name  (boat-like ),  is  directed  down- 
wards and  inwards ;  this  is  likewise  articular  and 
receives  the  head  of  the  os  magnum :  con- 
tinuous with  and  to  the  inner  side  of  this 
hollow  surface,  there  is  a  plane  one  of  a  semi- 
lunar form,  with  which  the  os  lunare  is  articu- 
lated. The  scaphoid  bone  articulates  with  the 
trapezium  and  trapezoides,  by  a  convex  surface 
directed  downwards  and  outwards.  Externally 
this  bone  terminates  in  a  pointed  extremity 
which  receives  the  external  lateral  ligament  of 
the  wrist-joint  and  the  annularligament  ( tuber- 
culum  ossisnaviculuris,  s.eminentia  carpiradialis 
superior).  The  anterior  and  posterior  surfaces 
of  the  bone  are  rough,  and  give  attachment  to 
the  anterior  and  posterior  radio-carpal  ligaments. 

2.  Os  lunare,  (os  semilunare  v.  iunatum ; 
Fr.  le.  semilunaire ;  Germ,  das  Mondbein), 
situated  between  the  scaphoid  and  the  cunei- 
form bones,  it  presents  four  articular  surfaces  ; 
an  upper  one,  convex  and  somewhat  triangular 
in  its  outline,  articulated  with  the  radius;  an 
inferior  one,  very  much  hollowed  from  before 
backwards  (to  the  crescentic  form  of  which  the 
bone  owes  its  name),  articulated  with  the  os 
magnum;  an  external  surface,  plane  and 
square,  adapted  to  the  cuneiform  bone ;  and, 
lastly,  an  internal  surface,  by  which  it  articu- 
lates with  the  scaphoid. 

3.  Os  cuneiforme  (os  triquetrum  s.  pyra- 
midale;  Fr.  le  pj/ramidale;  Germ,  dasdreiseitige 
Bein).  This  bone  terminates  the  superior 
carpal  row  on  the  ulnar  side;  its  upper  surface 
is  partly  smooth,  encrusted  with  cartilage  in 
the  recent  state,  where  it  is  in  contact  with  the 
triangular  ligament  of  the  wrist-joint,  and 
partly  rough  where  it  gives  attachment  to  liga- 
ments. Externally  it  articulates  with  the  cunei- 
form bone,  and  inferiorly  with  the  unciform 
by  a  large  and  concave  suaface.  The  inner 
half  of  its  anterior  surface  articulates  with  the 
pisiform  bone,  and  the  radial  half  of  the  same 
surface  is  rough  for  ligamentous  insertion. 

The  three  bones  just  described,  constituting 
the  superior  row  of  the  carpus  when  united, 
present  on  their  superior  aspect  a  convex  arti- 
cular surface  which  forms  the  carpal  portion 
of  the  radio-carpal  joint,  the  scaphoid  and 
lunar  being  articulated  with  the  radius,  while 
the  cuneiform  glides  upon  the  triangular  carti- 
lage of  the  wrist. 

4.  Os  pisiforme  (from  pisum,  a  pea;  Fr. 
le  pisiforme;  Germ,  das  Erbsenbein).  This 
little  bone  projects  at  the  anterior  part  of  the 
ulnar  extremity  of  the  superior  carpal  row; 
it  forms  what  some  anatomists  designate 
eminentia  carpi  ulnuris  superior,  being  part  of 
the  bony  ridge  already  referred  to  on  the  ulnar 
side  of  the  carpus.    The  prominence  produced 


506 


BONES  OF  THE  HAND. 


by  this  bone  is  easily  felt  during  life,  more 
especially  during  flexion  of  the  wrist-joint. 
It  is  round  every  where,  except  posteriorly, 
where  it  presents  a  flat  circular  surface,  by 
which  it  is  articulated  with  the  cuneiform  bone. 
This  bone  is  intimately  connected  with  and 
as  it  were  inclosed  in  the  terminal  portion  of 
the  tendon  of  the  flexor  carpi  ulnaris. 

5.  Os  trapezium  (os  multangulum  majus ; 
Fr.  le  trapeze ;  Germ,  das  grouse  vielysinkliche 
Bein ).  This  bone  is  situated  at  the  radial 
extremity  of  the  inferior  carpal  row,  having  the 
scaphoid  above  it  and  the  metacarpal  bone  of 
the  thumb  below  it.  We  may  describe  six 
surfaces  upon  it,  four  articular  and  two  non- 
articular,  a.  A  large  articular  surface,  situated 
on  the  external  and  inferior  aspect  of  the  bone. 
This  surface  is  for  articulation  with  the  meta- 
carpal bone  of  the  thumb :  it  is  somewhat  oval 
in  form,  the  long  axis  passing  from  without 
inwards  and  downwards ;  in  this  direction  it  is 
concave,  from  before  backwards  it  is  convex. 
The  three  remaining  articular  surfaces  are  on 
the  internal  and  superior  aspects  of  the  bone. 

b.  Internally,  a  very  small  plane  surface, 
adapted  to  a  corresponding  one  on  the  radial 
side  of  the  carpal  extremity  of  the  second 
metacarpal  bone.  c.  Above  the  last  described 
surface  and  separated  from  it  merely  by  a  slight 
ridge,  we  find  one  of  a  somewhat  triangular  form 
and  slightly  concave,  articulated  with  the  radial 
side  of  the  trapezoid,  d.  Quite  on  the  superior 
aspect  a  small  semicircular  surface,  adapted 
to  the  scaphoid.  Of  the  non-articular  surfaces, 
one  is  on  the  palmar  aspect  of  the  bone,  and 
is  easily  distinguished  by  the  prominent  ridge 
or  tubercle  at  its  outer  part,  which  gives  attach- 
ment to  the  annular  ligament,  ( tuberculum, 
eminent ia  carpi  radialis  inferior ;)  and  on  the 
ulnar  side  of  this  ridge  a  groove  in  which  the 
tendon  of  the  flexor  carpi  radialis  glides.  The 
second  non-articular  surface  is  on  the  dorsal 
aspect :  it  is  more  extensive  than  the  last, 
rough  and  tuberculated,  affording  insertion  to 
ligaments. 

6.  Os  trapezoides  (os  multangulum  minus; 
Fr.  le  trapezoide ;  Germ,  das  K/eine  viel- 
winkliche  Bein ).  This  is  the  second  bone  of 
the  inferior  carpal  row  ;  it  has  the  os  trapezium 
on  its  radial  and  the  os  magnum  on  its  ulnar 
side,  the  scaphoid  above  and  the  second  meta- 
carpal bone  below  it.  We  describe  four  articular 
surfaces  and  two  non-articular,  a.  The  inferior 
one  the  largest,  quadrilateral,  much  narrower 
in  front  than  behind,  convex  from  side  to  side, 
slightly  concave  from  before  backwards,  is 
entirely  devoted  to  articulation  with  the  second 
metacarpal  bone.  b.  On  the  radial  side,  a 
slightly   convex  surface  for  the  trapezium. 

c.  Superiorly  a  quadrilateral  concave  surface 
for  articulation  with  the  scaphoid,  d.  On  the 
ulnar  side  a  very  small  surface,  adapted  to  a 
corresponding  one  on  the  radial  side  of  the  os 
magnum.  The  palmar  surface  is  non-articular, 
five-sided,  slightly  excavated,  and  rough  from 
the  insertion  of  ligaments.  The  dorsal  surface, 
also  non- articular,  is  of  greater  extent,  con- 
vex, and  likewise  rough. 

7.  Os  magnum  ( os  capitatum  ;  Fr.  le  grand 


os;  Germ,  das  Kupfbein).  This  bone  is,  as 
its  name  implies,  principally  characterized  by 
its  excess  in  size  over  the  other  carpal  bones, 
and  from  the  number  of  bones  with  which  it  is 
connected,  it  may  be  regarded  as  the  key-bone 
of  the  carpus.  Superiorly  it  is  in  the  form  of 
a  rounded  head  (capitulum),  flattened  on  the 
ulnar  side,  where  it  articulates  with  the  unciform 
bone.  The  superior  prominent  portion  of  this 
head  is  received  into  the  excavation  of  the  lunar 
bone,  and  by  its  radial  side  it  articulates  with 
the  inferior  hollow  surface  of  the  scaphoid. 
The  inferior  portion  of  the  bone  is  cuboid,  and 
has  been  called  the  body  ;  it  is  rough  and  con- 
vex on  its  palmar  surface,  also  rough  but 
irregular  on  its  dorsal,  both  these  surfaces 
affording  insertion  to  numerous  ligaments. 
Inferiorly  we  notice  an  extensive  articular  sur- 
face, which  is  adapted  in  the  centre  to  the 
third  metacarpal  bone,  on  the  radial  side  to  the 
second,  and  by  a  very  small  portion  on  the 
ulnar  side  to  the  fourth  metacarpal  bone.  On 
the  ulnar  side  of  its  inferior  portion  it  articu- 
lates a  second  time  with  the  os  unciforme 
by  a  small  circular  articular  surface,  the  cir- 
cumference of  which  nearly  equals  that  of  the 
flat  surface  of  a  split  pea.  Lastly,  on  its  radial 
side  it  articulates  with  the  trapezoid  bone. 
Thus  the  os  magnum  articulates  with  seven 
bones ;  three  metacarpal  bones,  two  carpal 
bones  in  the  inferior  row,  and  two  in  the  supe- 
rior row. 

8.  Os  unciforme  (from  uncus,  a  hook,  os  ha- 
matum;  Fr,  p os  crocliu  ou  unciforme;  Germ. 
das  Hakenbein,  oder  Keilformiger  Knocfien ). 
This  bone  has  received  its  name  from  that 
which  allows  of  its  being  easily  distinguished 
from  all  the  carpal  bones, — namely,  the  hooked 
process,  which  projects  from  the  radial  edge  of 
its  palmar  surface.  This  process  constitutes  a 
considerable  prominence  on  the  ulnar  side  of 
the  carpus  (eminentia  carpi  ulnaris  inferior ), 
and  affords  insertion  to  the  annular  ligament. 
Its  concavity  looks  towards  the  radial  side  of 
the  carpus ;  the  remainder  of  the  palmar  sur- 
face is  rough  for  ligamentous  insertion.  The 
dorsal  surface  is  likewise  rough,  convex,  and 
of  considerable  extent.  This  bone  articulates 
inferiorly  with  the  fourth  and  fifth  metacarpal 
bones,  on  its  radial  side  with  the  os  magnum,  and 
on  its  superior  surface  with  the  cuneiform  bone. 

Structure  of  the  carpal  bones. — These  bones 
are  chiefly  composed  of  the  reticular  osseous 
tissue,  to  which  their  extreme  lightness  is  attri- 
butable, the  surface  being  invested  by  a  thin 
layer  of  compact  texture,  in  this  respect  per- 
fectly resembling  the  bones  of  the  tarsus. 

Developement. — The  carpal  bones  are  very 
late  in  their  developement;  at  birth  they  are 
completely  cartilaginous.  According  to  Cru- 
veilhier,  each  bone  is  developed  by  a  single 
point  of  ossification.  The  os  magnum  and  os 
unciforme  are  the  first  in  which  the  ossific  pro- 
cess commences,  about  the  end  of  the  first 
year;  between  the  third  and  fourth  years  it 
begins  in  the  cuneiform,  a  year  later  in  the 
trapezium  and  lunar,  and  between  the  eighth 
and  ninth  years  in  the  scaphoid  and  trapezoid 
bones.    The  ossification  of  the  pisiform  does 


BONES  OF  THE  HAND. 


507 


not  begin  till  between  the  twelfth  and  fifteenth 
years,  and  Cruveilhier  states  that  of  all  the 
bones  of  the  skeleton  it  is  the  last  in  which  the 
process  of  ossification  is  completed. 

II.  Metacarpus  (Germ,  die  Mdtelhand). 
Five  bones  constitute  the  metacarpus,  the  four 
internal  ones  being  parallel  to  each  other,  the 
external  one  diverging  outwards  at  an  acute 
angle  with  the  middle  line  of  the  hand.  These 
bones  vary  in  length  from  about  two  inches  and 
a  half  to  one  inch  six-eighths.  They  articulate 
inferiorly  with  the  superior  or  metacarpal  pha- 
langes, and  superiorly  with  the  carpus. 

Each  metacarpal  bone  presents  two  extremi- 
ties, and  a  shaft  or  body  between  them.  The 
superior  or  carpal  extremity  is  expanded  and 
wedge-shaped,  the  broader  part  being  towards 
the  dorsal  aspect.  Three  articular  surfaces 
exist  on  each ;  one,  the  most  extensive,  on  the 
superior  or  carpal  surface,  for  articulation  with 
a  carpal  bone ;  the  other  two  on  the  radial  and 
ulnar  surfaces,  adapted  to  the  adjacent  meta- 
carpal bone  or  to  a  carpal  bone.  The  palmar 
and  dorsal  surfaces  are  rough  and  irregular, 
and  afford  insertion  to  the  ligaments  which 
strengthen  the  earpo-metacarpal  joints.  The 
inferior  or  digital  extremity  is  in  the  form  of  a 
rounded  head,  flattened  on  each  side,  where 
we  notice  a  depression,  and  behind  it  a  tubercle 
which  affords  insertion  to  the  lateral  ligament 
of  the  joint.  The  smooth  articular  surface  of 
the  head  extends  further  upon  the  palmar  sur- 
face of  the  bone  than  upon  its  dorsal  surface, 
or,  as  in  the  case  of  the  metatarsal  bones,  more 
on  the  side  of  flexion  than  on  that  of  extension. 
The  shaft  or  body  is  prismatic  and  slightly 
curved,  so  as  to  present  a  concavity  towards  the 
palmar  surface,  and  a  convexity  to  the  dorsal. 

The  metacarpal  bones  are  numbered  from 
without  inwards.  The  first,  or  that  of  the 
thumb,  is  the  shortest  of  all  and  likewise  the 
thickest.  Its  carpal  extremity  will  likewise 
serve  to  distinguish  this  bone ;  it  wants  the 
cuneiform  shape,  and  is  rather  wider  on  its 
palmar  than  its  dorsal  surface.  It  has  no  arti- 
cular facets  on  its  sides,  being  articulated  with 
the  trapezium  alone  by  means  of  a  surface 
which  is  concave  from  before  backwards,  and 
convex  from  side  to  side;  the  body  of  this  bone 
is  flatter  on  its  palmar  and  dorsal  surfaces  than 
any  of  the  others. 

The  second  metacarpal  bone  is  the  longest ; 
it,  however,  exceeds  the  third  by  a  very  slight 
difference.  It  is  further  distinguished  from  the 
third  by  the  diminutive  size  of  the  articular 
facet  on  the  radial  side  of  its  carpal  extremity. 

The  third,  metacarpal  bone,  though  shorter 
than  the  second,  is  manifestly  thicker  and 
stronger;  this  excess  of  developement  being 
attributable  to  its  affording  insertion  to  one  of 
the  most  powerful  muscles  of  the  hand, — ■ 
namely,  the  adductor  pollicis. 

The  fourth  and  fifth  metacarpal  bones  are 
shorter  and  in  every  way  smaller  than  the  pre- 
ceding ones.  The  fifth  is  shorter  and  somewhat 
thicker  than  the  fourth  :  it  has  no  articular  facet 
on  the  ulnar  side  of  its  carpal  extremity,  but 
presents  a  prominent  tubercle  in  that  situation 
for  the  insertion  of  the  extensor  carpi  ulnaris. 


The  structure  of  the  metacarpal  bones  is  the 
same  as  that  of  the  long  bones  in  general. 

Developement. — There  are  two  points  of 
ossification  for  each  metacarpal  bone,  one  for 
the  body  and  the  carpal  extremity,  the  other 
for  the  digital  extremity.  The  first  metacarpal 
bone,  however,  according  to  Cruveilhier,  offers 
an  exception  to  this,  inasmuch  as  its  carpal 
extremity  is  developed  from  a  point  of  ossifica- 
tion distinct  from  that  of  the  body.  In  some 
instances  there  are  three  points  of  ossification 
for  each  metacarpal  bone.  The  bodies  of  the 
metacarpal  bones  are  completely  ossified  at 
birth.  Between  the  second  and  third  years 
appear  the  points  for  the  inferior  extremity  in 
the  four  inner  bones  and  the  superior  extremity 
in  the  first,  but  the  complete  fusion  of  the 
extremities  with  the  shafts  does  not  take  place 
till  near  the  twentieth  year. 

III.  Fingers  ( dixit i;  Fr.  les  doigts ;  Germ. 
die  Finger ).  The  fingers  differ  strikingly  from 
the  toes  as  regards  their  length,  to  which,  in- 
deed, is  due  their  greater  mobility.  They  are 
numbered  in  proceeding  from  the  radial  to  the 
ulnar  side  of  the  hand.  All  except  the  thumb 
are  composed  of  three  phalanges,  the  superior 
or  metacarpal,  the  middle,  and  the  inferior  or 
lingual:  in  the  thumb  the  middle  phalanx  is 
absent.  The  fingers  differ  considerably  in  length  ; 
the  thumb  is  by  far  the  shortest,  and  the  middle 
finger  is  the  longest.  Next  in  length  is  the 
ring  finger,  then  the  index,  and  last  and  least 
the  little  finger. 

The  metacarpal  phalanges  have  the  following 
general  characters: — 1st,  a  body  slightly  con- 
cave from  above  downwards  on  the  palmar 
surface,  and  convex  on  the  dorsal ;  2d,  a  supe- 
rior or  metacarpal  extremity  more  expanded 
than  the  inferior,  hollowed  into  an  articular 
surface  for  the  head  of  the  metacarpal  bone ; 
and  3d,  an  inferior  extremity,  having  a  pulley- 
like surface  for  articulation  with  the  middle 
phalanx.  The  metacarpal  phalanges  are  the 
longest. 

The  middle  phalanges  present  the  same  cha- 
racters as  the  preceding  as  regards  the  body. 
The  superior  extremity  has  a  pulley-like  articu- 
lar surface,  convex  transversely ;  that  of  the 
inferior  extremity  being  concave  in  the  same 
direction. 

The  ungual  phalanges  are  readily  distin- 
guished by  the  inferior  or  ungual  extremity, 
which  is  rough,  non-articular,  horseshoe-shaped, 
with  the  convexity  directed  downwards.  It  is 
this  part  of  the  bone  which  supports  the  nail. 
The  superior  extremity  is  articulated  with  the 
middle  phalanx  by  a  pulley-like  surface,  con- 
cave transversely.  The  ungual  phalanx  of  the 
thumb  is  considerably  larger  than  that  of  any 
of  the  other  fingers. 

In  point  of  structure  and  developement  the 
phalanges  scarcely  differ  from  the  metacarpal 
bones.  There  are  two  points  of  ossification, 
one  for  the  body  and  inferior  extremity,  the 
other  for  the  superior  extremity.  This  last  is 
late  in  making  its  appearance,  not  until  between 
the  third  and  seventh  year,  while  the  ossifica- 
tion of  the  body  commences  at  an  early  period 
of  intia-utenne  life. 


508 


BONES  OF  THE  HAND. 


Although  the  perfect  prehensile  hand  is  pecu- 
liar to  man  and  the  Quadrumana,  the  inferior 
segment  of  the  anterior  extremity  will  be  found 
to  possess  many  interesting  analogies  through- 
out the  mammiferous  series.  On  this  point  we 
refer  to  the  articles  Osseous  System  (Comp. 
Anat.)  and  Skeleton. 

JOINTS  OF  THE  HAND. 

Joints  of  the  carpus. — The  bones  consti- 
tuting each  row  of  the  carpus  are  firmly  con- 
nected by  strong  ligaments,  so  that  their  com- 
bined surfaces  form  one  extended  surface 
adapted  to  the  radius,  or  to  the  metacarpus,  or 
to  each  other.  Thus  the  union  of  the  superior 
articular  surfaces  of  the  upper  carpal  row  con- 
stitutes the  convex  surface  that  contributes  to 
the  formation  of  the  wrist-joint,  whilst  the 
united  inferior  articular  surfaces  of  the  same 
row  are  adapted  to  the  united  superior  surfaces 
of  the  inferior  carpal  row.  Again,  the  inferior 
articular  surfaces  of  this  last  row  enter  into  the 
formation  of  the  carpo-metacarpal  joints. 
-  The  several  articulations  of  each  row  are 
strengthened  by  two  sets  of  ligaments,  one  on 
the  palmar,  the  other  on  the  dorsal  surface  of 
the  joints,  palmar  and  dorsal  ligaments;  they 
extend  transversely  from  one  bone  to  the  other. 
The  palmar  ligaments  are  considerably  stronger 
than  the  dorsal.  The  synovial  membranes 
which  exist  in  these  small  articulations  are 
merely  offsets  from  the  large  synovial  mem- 
brane which  is  interposed  between  the  two 
rows  of  the  carpus. 

In  the  articulation  between  the  scaphoid  and 
lunar  bones,  as  well  as  in  that  between  the 
lunar  and  cuneiform,  we  observe  a  remarkable 
fibre-cartilaginous  lamina  interposed  in  the 
whole  extent  of  each  articulation  from  before 
backwards,  although  not  extending  over  the 
entire  articular  surfaces.  These  lamina;  are 
readily  seen  on  opening  the  radio-carpal  joint 
in  the  interval  between  the  bones  above  men- 
tioned ;  they  are  attached  to  the  palmar  and 
dorsal  ligaments  by  their  anterior  and  posterior 
extremities.  When  dissected  out  they  will  be 
found  to  be  wedge-shaped,  the  thick  edge  being 
directed  towards  the  wrist-joint,  and  adherent 
to  the  synovial  membrane  of  that  joint.  These 
laminae  are  described  by  most  anatomists  as 
ligaments,  under  the  name  of  interosseous  liga- 
ments. Of  their  fibro-cartilaginous  nature, 
however,  I  have  no  doubt  from  repeated  and 
careful  examinations;  they  may  therefore  be 
more  correctly  denominated  interosseous  fibro- 
cartilages.  Feeble  interosseous  ligaments  exist 
on  either  side  of  the  os  magnum  between  it 
and  the  unciform  on  one  side,  and  the  trapezoid 
on  the  other ;  they  are  best  seen  when  these 
bones  are  torn  from  each  other. 

Articulation  of  the  two  rows  of  carpal  bones 
to  each' other. — The  superior  articular  surfaces 
of  the  four  bones  composing  the  inferior  carpal 
row  are  adapted  to  the  inferior  articular  surfaces 
of  the  scaphoid,  lunar,  and  cuneiform  bones. 
The  head  of  the  os  magnum  and  the  superior 
articular  surface  of  the  unciform  bone  form  a 
prominent  convexity,  which  is  received  into  a 
deep  concavity  formed  on  the  ulnar  side  by  the 
cuneiform  bone,  on  the  radial  side  by  the 


scaphoid,  and  in  the  centre  by  the  lunar  bone ; 
whilst  external  to  the  projection  of  the  os  mag- 
num, a  superficial  oblong  concavity  receives  the 
convexity  on  the  inferior  and  outer  surface  of 
the  scaphoid.  Thus  the  line  of  this  articulation 
has  somewhat  of  the  course  of  the  roman  S 
placed  horizontally,  w.  That  part  of  the  arti- 
culation which  is  to  the  ulnar  side,  then,  par- 
takes more  of  the  nature  of  enarthrodia  or  ball 
and  socket  joint,  while  that  to  the  radial  side 
is  arthrodia  with  almost  plane  surfaces. 

This  articulation  is  strengthened  in  front  by 
an  anterior  or  palmar  ligament  which  is  of 
considerable  strength  and  thickness.  Most  of 
the  fibres  of  this  ligament  are  attached  inferiorly 
to  the  palmar  surface  of  the  os  magnum, 
whence  they  diverge  to  be  inserted  into  the 
scaphoid,  lunar,  and  cuneiform  bones;  some 
few  fibres  extend  from  the  trapezoid  and  trape- 
zium to  the  scaphoid,  and  from  the  unciform 
to  the  cuneiform.  Behind  we  find  a  dorsal 
ligament,  also  strong,  although  much  less  so 
than  the  palmar.  This  ligament  extends 
obliquely  from  the  bones  of  the  first  row  to 
those  of  the  second,  but  is  stronger  on  the  ulnar 
than  on  the  radial  side.  The  extent  and  con- 
nexions of  both  these  ligaments  are  best  seen 
when  the  joint  is  opened,  by  cutting  through 
the  dorsal  ligament  to  view  the  palmar,  and 
vice  versa.  The  ligaments  called  lateral  by 
some  anatomists  are  merely  the  continuation  of 
the  lateral  ligaments  of  the  wrist-joint ;  nor  do 
those  described  by  Cruveilhier  under  the  name 
of  glenoid  ligaments  deserve  to  be  separated 
from  the  anterior  and  posterior,  of  which  they 
constitute  that  portion  most  intimately  connected 
with  the  anterior  and  posterior  notches  of  the 
hollow  cavity  in  which  the  head  of  the  os  mag- 
num is  lodged. 

In  opening  this  joint  in  the  manner  already 
described,  it  will  be  seen  how  extensive  is  its 
synovial  membrane.  It  extends  some  distance 
on  the  palmar  and  dorsal  surfaces  of  the  neck 
of  the  os  magnum,  and  sends  two  processes 
between  the  bones  of  the  first  row  (between 
the  scaphoid  and  lunar,  and  the  lunar  and 
cuneiform),  and  three  processes  between  those 
of  the  second  row,  (one  on  each  side  of  the 
os  magnum,)  and  one  between  the  trapezium 
and  trapezoid. 

Motions  of  the  carpal  articulations. — An 
examination  of  the  dissected  carpus  will  at 
once  show  how  limited  are  the  motions  between 
any  two  of  the  carpal  bones  of  each  row.  The 
movement  of  one  row  upon  the  other,  however, 
is  more  extensive,  but  only  in  the  direction  of 
flexion  and  extension,  the  former  being  con- 
siderably greater  in  consequence  of  the  less 
resistance  of  the  dorsal  ligaments.  Solidity 
and  strength,  a  power  of  resistance  to  violence 
which  might  easily  occasion  fracture,  were  the 
carpus  one  solid  bone,  are  gained  by  the  num- 
ber of  small  bones  of  which  it  is  composed, 
the  arthrodial  form  of  its  articulations,  and  the 
strong  ligaments  by  which  the  motions  of  these 
joints  are  restricted. 

Articulation  of  the  pisiform  bone.  —  The 
pisiform  bone  is  so  little  connected  with  the 
mechanism  of  the  carpus  that  its  articulation 


BONES  OF  THE  HAND. 


509 


with  the  cuneiform  bone  demands  a  separate 
consideration.  A  plane  oval  surface  on  the 
posterior  part  of  the  pisiform  is  articulated 
with  a  corresponding  one  on  the  palmar  aspect 
of  the  cuneiform,  and  several  strong  ligaments 
strengthen  the  joint.  Two  lateral  ligaments 
pass  from  the  pisiform  to  the  cuneiform  bone, 
the  internal,  which  is  also  anterior,  being  of 
considerable  strength.  This  bone  is  further 
connected  to  the  unciform  by  strong  ligament- 
ous fibres;  and  a  strong  bundle,  which  bears  the 
same  relation  to  the  tendon  of  the  flexor  carpi 
ulnaris  as  the  ligamenturn  patella?  does  to  the 
tendon  of  the  rectus  femoris,  extends  to  the 
carpal  extremity  of  the  fifth  metacarpal  bone. 
This  joint  is  provided  with  a  loose  synovial 
membrane ;  its  motions  are  those  of  gliding 
in  the  directions  of  the  axis  of  the  articular 
surfaces. 

Carpo-metacarpal  joints. — These  are  very 
strong  articulations,  and,  with  the  exception  of 
the  first  and  fifth,  enjoy  a  very  limited  extent 
of  motion.  The  four  internal  ones  are  nearly 
plamform  arthrodiee,  restricted  on  the  palmar 
and  dorsal  surfaces  by  strong  and  short  liga- 
ments ( palmar  and  dorsal  ligaments ),  the  latter 
being  much  better  developed.  The  second 
metacarpal  bone  is  articulated  with  the  trapezoid 
in  an  extremely  firm  manner:  its  palmar  liga- 
ment extends  from  the  extremity  of  the  meta- 
carpal bone  to  the  trapezium  internal  to  the 
ridge,  and  covered  by  the  tendon  of  the  radial 
flexor  of  the  wrist.  There  are  three  dorsal 
ligaments,  an  external  attached  to  the  trapezium, 
and  an  internal  to  the  os  magnum.  These  two 
ligaments  are  oblique  in  their  direction ;  the 
third  or  middle  one  is  vertical  and  attached  to 
the  trapezoid.  The  third  metacarpal  bone  is  arti- 
culated with  the  os  magnum :  here  we  find 
three  strong  palmar  ligaments,  an  external  one 
which  extends  obliquely  outwards  to  the  trape- 
zium, an  internal  one  which  passes  in  front  of 
the  carpal  extremity  of  the  fourth  metacarpal 
bone,  adhering  to  it,  and  inserted  into  the 
unciform  and  the  fifth  metacarpal  bone,  and  a 
middle  one  which  passes  vertically  to  the  os 
magnum.  This  joint  has  two  dorsal  ligaments, 
both  inserted  into  the  os  magnum.  The  fourth 
metacarpal  bone  is  articulated  with  the  radial 
portion  of  the  inferior  articular  surface,  and 
with  a  very  small  portion  of  the  os  magnum; 
it  has  a  single  palmar  and  dorsal  ligament. 
The  fifth  metacarpal  bone  is  articulated  with 
the  outer  part  of  the  inferior  surface  of  the 
unciform ;  this  surface  is  convex  transversely 
and  concave  from  befdre  backwards,  while  that 
on  the  metacarpal  bone  is  convex  from  before 
backwards  and  concave  transversely.  The 
proper  ligaments  of  this  joint  are  very  feeble, 
being  merely  a  few  fibres  attached  to  the  ante- 
rior and  posterior  surfaces  of  the  synovial  mem- 
brane. The  joint,  however,  is  protected  in 
front  by  the  prominence  of  the  unciform  pro- 
cess, which  descends  a  little  below  the  line  of 
the  articulation,  and  limits  the  forward  motion 
of  the  carpal  extremity  of  the  bone ;  and  pos- 
teriorly it  is  strengthened  by  the  tendon  of  the 
extensor  carpi  ulnaris,  while  its  motion  ulnad 
is  restricted  by  the  strong  internal  palmar  liga- 


ment of  the  third  metacarpal  bone,  which  we 
have  already  described  as  passing  from  that 
bone  to  the  fifth  metacarpal  and  the  unciform 
bones.  The  fifth  carpo-metacarpal  articulation 
approaches  in  many  particulars  to  the  first;  it 
has  a  greater  latitude  of  motion  than  the  three 
immediately  preceding  it,  and  its  articular  sur- 
faces very  much  resemble  those  of  the  first. 

Besides  the  palmar  and  dorsal  ligaments 
already  described,  these  metarearpal  bones  are 
very  firmly  connected  to  each  other  by  short 
but  strong  ligaments,  extending  transversely 
from  one  to  the  other  on  the  palmar  and  dorsal 
aspects. 

A  common  synovial  membrane  extends 
throughout  the  four  joints  above  described  ; 
this  synovial  membrane  is  continuous  with  that 
between  the  two  rows  of  carpal  bones. 

The  digital  extremities  of  the  four  inner 
metacarpal  bones  are  connected  by  their  trans- 
verse ligaments  situated  at  the  palmar  surface 
and  extending  from  one  to  the  other. 

Curpo-metucurpal  joints  of  the  thumb. — The 
main  feature  by  which  this  articulation  is  dis- 
tinguished from  the  other  carpo-metacarpal 
joints  is  its  great  mobility.  It  is  an  arthrodia, 
and  in  many  particulars  resembles  very  much 
the  sterno-clavicular  joint.  The  trapezium 
presents  a  surface  concave  from  within  out- 
wards, and  convex  from  before  backwards, 
that  on  the  metacarpal  bone  being  convex  in 
the  transverse,  and  concave  in  the  antero-pos- 
terior  direction. 

The  ligamentous  apparatus  of  this  joint  has 
"very  much  the  appearance  of  the  capsular 
ligament  of  an  enarthrosis,  and  has  indeed 
been  described  as  such  by  many  anatomists ; 
but  on  a  careful  examination  it  will  be  found 
to  consist  of  separate  bundles  of  ligament 
placed  at  those  situations  in  which  the  greatest 
tendency  to  displacement  exists  in  the  various 
motions  of  the  joint.  Four  principal  bundles 
may  be  described  :  one  very  thick  and  strong, 
situated  at  the  posterior  and  outer  part  of  the 
joint,  (tig.  dorsale,  Weitbr.)  extending  from 
the  metacarpal  bone  to  a  prominent  tubercle 
on  the  outer  part  of  the  dorsal  surface  of  the 
trapezium;  this  ligament  limits  flexion  of  the 
joint.  A  second  ligament  is  situated  directly 
in  front  of  the  joint,  (lig.  palmare,  Weitbr.) 
is  inserted  into  the  trapezium  immediately 
internal  to  its  prominence;  extension  is  limited 
by  this  ligament.  The  third  and  fourth  bundles 
(lig-  laterale  ext.  et  int.  Weitbr.)  are  situ- 
ated on  the  radial  and  ulnar  sides  of  the  joint : 
they  are  less  distinct  as  well  as  less  strong  than 
those  last  described.  That  on  the  ulnar  side 
is  considerably  the  stronger;  it  limits  abduc- 
tion of  the  thumb,  whilst  that  on  the  radial 
side  limits  adduction. 

The  synovial  membrane  of  this  joint  is  lax ; 
it  is  perfectly  distinct  from  the  general  syno- 
vial membrane  of  the  other  carpo-metacarpal 
articulations. 

Motions  of  the  carpo-metacarpal  joints. — 
In  the  second,  third,  and  fourth  joints  the 
motions  are  limited  to  a  very  slight,  and  during 
life  scarcely  appreciable  gliding  forwards  or 
backwards :  the  strong  transverse  ligaments, 


510 


ABNORMAL  CONDITIONS  OF  THE  HAND. 


as  well  as  the  close  manner  in  which  the  carpal 
extremities  of  the  metacarpal  bones  are  im- 
pacted together,  render  lateral  motion  impos- 
sible ;  in  the  fifth  joint  the  forward  or  back- 
ward motion  is  somewhat  more  extensive,  but 
this  joint  is  equally  limited  with  the  others  in 
lateral  movement. 

The  carpo-metacarpal  joint  of  the  thumb 
enjoys  motion  forwards,  backwards,  inwards, 
and  outwards,  producing  the  movements  of 
flexion  and  extension,  abduction  and  ad- 
duction. The  power  of  opposing  the  thumb 
to  any  of  the  fingers  is  due  to  the  oblique 
direction  of  flexion  in  this  joint:  the  bone 
moves  forwards  and  inwards,  passing  through 
a  line  which  would  be  concave  inwards.  This 
is  by  far  the  most  extensive  motion  of  the 
thumb,  and  it  is  by  an  excess  of  this  motion 
that  the  dislocation  of  the  metacarpal  bone 
backwards  is  generally  occasioned.  Cruveil- 
hier  observes  that  the  weakness  of  the  posterior 
ligament  favours  the  occurrence  of  this  lux- 
ation. I  cannot,  however,  admit  the  weakness 
of  this  ligament ;  on  the  contrary,  it  appears 
to  me  to  be  the  strongest  of  all  the  ligaments 
of  this  joint ;  which  opinion,  I  find,  is  that  of 
the  accurate  Weitbrecht. 

The  motion  of  adduction  is,  on  the  other 
hand,  the  most  limited,  in  consequence  of  the 
proximity  of  the  second  metacarpal  bone ;  that 
of  abduction  is  very  extensive,  and  when  car- 
ried too  far  may  occasion  luxation  inwards. 

JOINTS  OF  THE  FINGERS. 

1.  Metacarpophalangeal  joints. — The  first 
phalanges  are  articulated  by  an  oval  concave 
surface,  with  the  rounded  oblong  heads  of  the 
inferior  extremities  of  the  metacarpal  bones  : 
it  is  remarkable  that  the  long  axis  of  the  oval 
concavity  of  the  phalanx  has  a  transverse  di- 
rection, while  the  long  axis  of  the  head  of  the 
metacarpal  bone  is  directed  from  before  back- 
wards, and  consequently  at  right  angles  with 
the  former ;  whence  the  great  extent  of  lateral 
motion  enjoyed  by  these  joints. 

Each  of  these  joints  is  strengthened  by  two 
lateral  ligaments,  of  considerable  strength, 
inserted  into  the  tubercle  behind  the  depression 
on  each  side  of  the  head  of  the  metacarpal 
bone ;  the  point  of  insertion  into  the  phalanx 
is  anterior  to  this,  and  consequently  the  direc- 
tion of  the  lateral  ligaments  is  downwards  and 
forwards;  as  they  descend,  these  ligaments 
spread  out,  and  their  anterior  fibres  become 
identified  with  the  anterior  ligament. 

A  third  ligament,  the  anterior  ligament,  or 
glenoid  ligament  of  Cruveilhier,  seems  des- 
tined more  to  increase  the  extent  of  the  pha- 
langeal articular  concavity  anteriorly,  than  to 
maintain  the  integrity  of  the  joint  or  limit  its 
motions.  This  ligament  is,  as  Bichat  expresses 
it,  a  thick  and  dense  fibrous  bundle,  in  shape 
half  a  ring,  placed  in  front  of  the  palmar  sur- 
face of  the  head  of  the  metacarpal  bone,  com- 
posed of  transverse  fibres  which  adhere  in- 
teriorly to  the  anterior  edge  of  the  concavity 
on  the  phalanx,  and  on  each  side  are  identified 
with  the  lateral  ligaments  and  the  transverse 
ligaments  by  which  the  metacarpal  bones  are 
connected.     If  the  ligaments  and  synovial 


membrane  of  this  joint  be  cut  all  round  close 
to  their  attachment  to  the  head  of  the  meta- 
carpal bone,  and  that  bone  be  removed,  the 
synovial  capsule  and  ligaments  remaining  at- 
tached to  the  phalanx,  a  very  clear  idea  of  the 
relative  positions  of  the  ligaments  may  be 
formed.  The  synovial  membrane  will  then 
appear  protected  on  three  sides  by  ligament ; 
on  the  radial  and  ulnar  side  by  the  lateral 
ligaments,  and  in  front  the  anterior  ligaments, 
whilst  posteriorly  it  is  unprotected  save  by  the 
sheath  of  the  extensor  tendon. 

In  the  metacaipo-phalangeal  articulation  of 
the  thumb  two  sesamoid  bones,  developed  in 
the  substance  of  the  anterior  ligament,  protect 
the  joint  in  front. 

2.  Phalangeal  joints. — These  joints  are  all 
ginglymoid,  the  articular  surfaces  being  pul- 
ley-like ;  they  are  provided  with  lateral  liga- 
ments similar  to  those  of  the  metacarpopha- 
langeal joints,  and  also  with  anterior  ligaments 
similarly  disposed. 

Motions  of  the  joints  of  the  fingers. — In 
the  phalangeal  joints  these  motions  are  only 
flexion  and  extension ;  the  former  are  con- 
siderably more  extensive,  and  are  favoured  by 
the  inferior  insertion  of  the  lateral  ligaments 
being  on  a  plane  anterior  to  their  superior 
insertion.  In  addition  to  flexion  and  exten- 
sion the  metacarpophalangeal  joints  enjoy  con- 
siderable lateral  motion,  which  is  due  to  the 
glenoid  form  of  the  phalangeal  articular  sur- 
face, and  to  the  enarthrodial  form  which  the 
joint  derives  from  the  extension  of  that  arti- 
cular surface  by  the  anterior  ligament. 

(R.  B.  Todd.) 

HAND, ABNORMAL  CONDITIONS  OF 
THE.  Deviations  from  the  normal  condition 
of  the  different  structures  which  enter  into  the 
composition  of  the  hand  are  very  numerous, 
and  may  be  classed  into  those  which  are  the 
result  of,  first,  accident;  second,  disease; 
third,  congenital  malformation. 

I.  ABNORMAL  CONDITIONS,  THE  RESULT  OF 
ACCIDENT. 

Fractures  and  luxations.  ■ —  Simple  frac- 
tures of  the  bones  of  the  hand  are  seldom 
followed  by  any  notable  deformity ;  but  lux- 
ations of  these  bones  require  from  us  some 
attention  here. 

Luxation  of  the  bones  of  the  carpus. — The 
bones  of  the  carpus  are  united  to  each  other  so 
solidly,  and  their  movements  seem  so  limited, 
that,  without  experience,  we  should  be  dis- 
posed to  pronounce  luxation  of  any  of  these 
bones  impossible ;  nevertheless,  the  head  of 
the  os  magnum  may  be  dislocated  from  the 
cavity  formed  for  it  by  the  scaphoid  and  semi- 
lunar bones.  The  first  range  of  the  bones  of 
the  carpus  is  articulated  with  the  bones  of  the 
second  range  in  such  a  manner  that  slight 
gliding  movements  of  flexion  and  extension  of 
the  hand  are  permitted,  which  augment  a  little 
the  movements  of  flexion  and  extension  of 
the  hand  upon  the  forearm,  and  add  some- 
what, as  Cruveilhier  says,  to  the  grace  of  the 
movements  of  this  portion  of  the  upper  ex- 


ABNORMAL  CONDITIONS  OF  THE  HAND. 


511 


tremity.  In  flexion,  the  head  of  the  os  mag- 
num, which  is  somewhat  inclined  backwards, 
raises  up  the  thin  capsule  which  surrounds  its 
articulation,  and,  if  this  movement  be  carried 
very  far,  the  capsule  and  accessory  fibres  which 
support  the  bone  posteriorly  are  broken,  and 
the  os  magnum  escapes  from  the  cavity  in  which 
it  is  naturally  placed ;  the  dislocation  cannot 
be  called  complete,  yet  the  os  magnum  passes 
somewhat  the  level  of  the  posterior  surface  of 
the  other  bones  of  the  carpus.  The  accident 
is  more  common  in  women  than  in  men,  no 
doubt  because  the  ligaments  are  weaker  and 
the  bones  enjoy  greater  motion  in  the  former 
than  in  the  latter ;  the  luxation  backwards  of 
the  os  magnum,  the  only  one  which  can  occur, 
is  always  the  result  of  a  forced  and  violent 
flexion  of  the  wrist,  such,  for  example,  as  a 
fall  on  the  back  of  the  hand  would  produce. 

We  recognize  the  luxation  of  the  os  mag- 
num by  the  history  of  the  accident,  and  by  the 
deformity  produced.  We  perceive  a  hard  cir- 
cumscribed tumour  which  has  suddenly  ap- 
peared on  the  back  of  the  hand  in  the  situation 
which  corresponds  to  the  head  of  the  bone. 
This  tumour  becomes  more  prominent  when 
the  hand  is  flexed,  and  diminishes  when  it  is 
extended ;  we  can  make  it  disappear  entirely 
by  a  slight  compression.  This  luxation  causes 
but  little  inconvenience,  but  the  head  of  the 
os  magnum  always  remains  more  salient  when 
the  hand  is  flexed,  and  forms  a  tumour  more 
or  less  marked  according  to  the  extent  of  the 
displacement. 

We  can  easily  reduce  this  luxation  by  ex- 
tending the  hand,  or  by  exercising  a  slight 
pressure  on  the  head  of  the  os  magnum ;  but, 
although  it  is  easy  to  make  the  bone  resume 
its  position  in  the  cavity  formed  for  it  by  the 
scaphoid  and  semilunar  bones,  it  is  very  dif- 
ficult to  maintain  it  there,  and  the  inconve- 
nience and  deformity  resulting  from  the  luxation 
are  so  trivial  that  few  persons  will  submit  with 
patience  to  the  means  usually  recommended. 

Luxation  of  the  bones  of  the  metacarpus. — 
Luxation  of  the  metacarpal  bone  of  the  thumb. 
The  carpal  head  of  the  metacarpal  bone  of  the 
thumb,  notwithstanding  the  range  of  motion  it 
enjoys,  is  rarely  dislocated.  Sir  A.  Cooper,  in 
his  extensive  experience,  has  seen  but  one  spe- 
cies of  this  accident,  viz.  luxation  of  the  meta- 
carpal bone  of  the  thumb  upon  the  os  trapezium, 
inwards.  "  In  the  cases  I  have  seen  of  this 
accident,"  says  Sir  Astley,  "  the  metacarpal 
bone  has  been  thrown  inwards  between  the  tra- 
pezium and  the  root  of  the  metacarpal  bone  of 
the  fore-finger;  it  forms  a  protuberance  towards 
the  palm  of  the  hand;  the  thumb  is  bent  back- 
wards, and  cannot  be  brought  towards  the  little 
finger:  considerable  pain  and  swelling  are  pro- 
duced by  this  accident." 

Luxation  of  the  carpal  head  of  the  meta- 
carpal bone  of  the  thumb  backwards.  Some 
surgeons  seem  to  doubt  that  the  metacarpal 
bone  of  the  thumb  is  capable  of  being  dis- 
located in  any  other  direction  than  that  in- 
wards; but  the  following  case  is  given  on  the 
highly  respectable  authority  of  the  experienced 
Boyer.    Madame  De  la  P          luxated  the 


metacarpal  bone  of  her  left  thumb  backwards 
on  the  dorsum  of  the  trapezium  by  falling  on 
the  external  or  radial  border  of  her  hand  ;  the 
luxation  was  at  first  mistaken.  When  Boyer 
saw  it  six  months  after  the  accident,  the  su- 
perior extremity  of  the  metacarpal  bone  of  the 
thumb  formed  posteriorly  a  very  remarkable 
prominence  on  the  trapezium,  and  this  bone 
and  the  phalanges  of  the  thumb  were  inclined 
towards  the  palm  of  the  hand.  On  pressing 
posteriorly  on  the  prominence  formed  by  the 
superior  extremity  of  the  dislocated  bone,  it 
could  be  made  to  resume  its  natural  place  and 
the  prominence  disappeared ;  so  long  as  the 
pressure  was  continued,  the  bone  retained  its 
place  and  the  thumb  enjoyed  its  natural  powers 
of  flexion  and  extension ;  but  as  soon  as  the 
pressure  was  remitted,  the  bone  became  dis- 
placed anew,  and  the  movements  of  the  thumb 
impossible.  The  lady  was  unwilling  to  sub- 
mit to  any  treatment,  and  the  condition  of  the 
joint  remained  unaltered.  These  luxations  of 
the  metacarpal  bone  of  the  thumb,  whether 
backwards  or  inwards,  must  be  rare,  as  the 
causes  which  are  calculated  to  produce  them 
must  act  through  the  first  phalanx  of  the  thumb, 
which,  it  is  manifest,  will  be  much  more  dis- 
posed to  yield  than  the  metacarpal  bone. 

Luxation  of  the  phalanges  of  the  fingers. — - 
The  first  phalanx  of  the  thumb  as  well  as  the 
first  phalanx  of  any  of  the  fingers  may  be 
luxated  backwards;  the  luxation  forwards  of 
the  phalanx  is  very  rare  and  perhaps  impossible, 
except  in  the  index  finger  and  the  thumb. 

The  mutual  support  which  the  first  pha- 
langes of  the  fingers  afford  each  other  laterally, 
and  the  strength  of  the  lateral  ligaments  render 
the  luxation  outwards  or  inwards  very  difficult. 

Luxations  of  the  first  phalanx  of  the  thumb 
from  the  metacarpal  bone.  The  first  phalanx 
of  the  thumb  may  be  luxated  forwards  to  the 
palmar  surface  of  the  metacarpal  bone,  but 
this  form  of  luxation  is  very  rare,  while  the 
luxation  of  the  same  phalanx  on  the  dorsum 
of  the  metacarpal  bone  is  the  most  common 
and  important  displacement  of  any  to  which 
the  bones  of  the  hand  are  liable.  We  shall 
therefore  consider  this  accident  in  detail. 

In  some  persons  the  first  phalanx  of  the 
thumb  can  at  will  be  dislocated  backwards, 
solely  by  the  contraction  of  the  muscles.  The 
displacement  produced  by  accident,  however, 
is  much  more  extensive  than  this,  which  may 
be  termed  the  voluntary  luxation.  When  the 
first  phalanx  of  the  thumb  is  in  a  state  of 
extreme  extension,  accident  may  dislocate  it 
on  the  dorsum  of  the  metacarpal  bone.  The 
signs  of  the  injury  are  so  evident  that  mistake 
appears  impossible;  the  first  phalanx  is  thrown 
back  as  if  pulled  by  its  two  extensors,  and 
forms  nearly  a  right  angle  with  its  metacarpal 
bone  (fig.  226) ;  the  head  of  the  latter  forms 
a  remarkable  tumour  at  the  anterior  part 
or  palmar  aspect  of  the  articulation,  while 
a  prominence  behind  points  out  the  situation 
of  the  base  of  the  first  phalanx :  the  last  or 
distal  phalanx  is  (in  recent  cases)  flexed,  and  it 
soon  becomes  difficult  or  impossible  to  extend 
it,  or  to  flex  the  first  phalanx. 


ABNORMAL  CONDITIONS  OF  THE  HAND. 


Fig.  226. 


Luxation  of  the  first  phalanx  of  the  thumb  on  the  hack 
of  the  metacarpal  bone. 

Anatomical  characters  of  this  accident.  Op- 
portunities of  ascertaining  by  dissection  the 
actual  condition  of  the  parts  when  luxation 
backwards  of  the  first  phalanx  of  the  thumb 
has  recently  happened,  of  course  do  not  occur, 
but  from  the  dissection  of  old  unreduced  in- 
juries of  this  kind,*  and  from  experiments  on 
the  dead  subject,  we  are  led  to  infer  that  the 
immediate  effects  of  the  injury  are,  extensive 
laceration  of  the  anterior  part  of  the  synovial 
membrane,  and  of  one  or  both  the  lateral  liga- 
ments, while  the  posterior  portion  of  the  cap- 
sule remains  entire  ;  the  base  of  the  first  pha- 
lanx is  dragged  to  a  considerable  extent  upon 
the  dorsum  of  the  metacarpal  bone,  elevating 
with  it  the  tendons  of  the  extensor  primi  and 
secundi  internodii  pollicis;  the  tendon  of  the 
flexor  pollicis  longus  is  carried  inwards  and 
under  the  head  of  the  metacarpal  bone.  As  the 
extensor  ossis  metarcarpi  and  opponens  pollicis 
are  not  attached  to  the  first  phalanx,  they  are 
little  affected  by  the  luxation,  but  the  con- 
dition of  the  three  remaining  muscles  which 
are  inserted  into  the  base  of  the  first  phalanx 
requires  consideration.  These  short  muscles 
are  the  abductor  pollicis,  the  flexor  pollicis 
brevis,  and  the  adductor  pollicis. 

When  the  dislocation  backwards  of  the  first 
phalanx  of  the  thumb  has  occurred,  the  large 
head  of  the  metacarpal  bone  is  at  the  same 
time  thrown  inwards  towards  the  palm,  and 
having  forced  its  way  between  the  two  origins 
of  the  flexor  pollicis  brevis,  the  shaft  of  this 
bone,  which  is  comparatively  much  narrower 
than  the  head,  becomes  tightly  embraced  by 
the  two  fleshy  columns  of  the  muscle.  This 
is  a  state  of  things  which  should  be  taken  into 
account  when  the  obstacles  to  the  reduction  of 
this  dislocation  are  considered,  nor  should  it 
be  forgotten  that  the  direction  and  relative 
position  of  the  points  of  attachment  of  all  the 
muscles  concerned  must  be  altogether  changed 
when  the  complete  luxation  has  occurred ; 
their  origins  and  insertions  are  more  than  na- 
turally approximated,  and  the  line  of  direction 
of  their  action  is  thrown  much  behind  the 

*  See  London  Medical  Gazette  for  Oct.  14,  1837, 
J.  A.  Lawrie,  Glasgow. 


longitudinal  axis  of  the  metacarpal  bone ;  the 
tendons  of  the  extensor  primi  and  secundi 
internodii,  and  of  the  flexor  pollicis  longus  are 
of  course  carried  by  the  dislocated  bone  behind 
then-  usual  line  of  action;  hence  the  action  of 
all  these  muscles,  after  the  luxation  has  oc- 
curred, becomes  materially  altered,  their  con- 
traction will  no  longer  be  resisted  by  the  lateral 
and  capsular  ligaments,  and  the  bone  will 
be  drawn  upwards  and  backwards  by  them, 
a  considerable  distance  on  the  dorsum  of 
the  metacarpal  bone  (Jig.  226).  The  flexors 
have  their  direction  so  altered  and  so  thrown 
behind  the  longitudiua)  axis,  of  the  metacarpal 
bone  of  the  thumb,  that  they  now  no  longer 
act  as  flexors  of  the  first  phalanx  to  approxi- 
mate it  to  the  palm  ;  on  the  contrary,  they  now 
have  become  extensors  of  the  dislocated  pha- 
lanx, and  tend  much  by  their  contraction  to 
increase  the  deformity.'* 

This  dislocation  is  difficult  to  reduce,  par- 
ticularly if  the  nature  of  the  accident  have  not 
been  speedily  recognized.  Various  causes  have 
been  assigned  for  the  opposition  to  the  return 
of  the  bone;  some  think  with  the  late  Mi.  Hey 
of  Leeds,  that  a  transverse  section  of  the  head 
of  the  metacarpal  bone  presents  in  its  outline 
somewhat  of  a  cuneiform  figure ;  and  that, 
in  consequence  of  the  narrowest  part  of  the 
wedge  being  thus  placed  anteriorly,  it  can 
easily  under  the  influence  of  accident  glide 
towards  the  palm  by  passing  between  the 
lateral  ligaments  which  remain  unbroken,  and 
resist  all  return  of  the  bone  backwards  to  its 
original  situation.  Others  imagine  that  the 
interposition  of  the  anterior  ligament  and 
sesamoid  bone  attached  to  it  between  the  arti- 
cular surfaces  constitutes  the  principal  ob- 
stacles to  the  reduction  of  this  luxation.  Again 
it  has  been  asserted  that  the  tendon  of  the 
flexor  longus  pollicis  has  been  twisted  spirally 
under  the  metacarpal  bone,  while  some  with 
more  appearance  of  truth  have  supposed  that 
the  muscles  are  the  principal  sources  of  re- 
sistance. The  learned  author  of  the  First  Lines 
of  Surgery  has  expressed  his  opinion  that  the 
return  of  the  dislocated  phalanx  to  its  place  is 
opposed  by  a  combination  of  causes,  viz. — 
the  cuneiform  shape  of  the  bone  and  the  re- 
sistance of  the  lateral  ligaments,  as  suggested 
by  Hey,  the  force  of  the  muscles,  and,  lastly, 
he  adds,  because  the  surface  for  the  applica- 
tion of  the  extending  means  is  very  limited. 
To  most  of  these  observations  we  have  reason 
to  object,  particularly  to  the  last,  because  we 
believe  that  all  the  force  which  it  is  justifiable 
to  use  may  be  easily  applied  ;  and  we  should 

*  In  the  experiments  made  by  my  colleaeue  Mr. 
Mayne  and  myself  on  the  dead  subject,  when  we 
forcibly  dislocated  the  first  phalanx  backwards,  we 
found  the  anterior  part  of  the  synovial  membrane 
and  the  external  lateral  ligament  torn  across  ;  the 
first  phalanx  was  placed  as  in  fig.  226.  We  found  the 
head  of  the  metacarpal  bone  driven  between  the  two 
heads  of  the  flexor  pollicis  brevis  in  such  a  way, 
that  the  external  head  of  the  muscle  was  placed 
upon  the  outside  of  the  shaft  of  the  bone  in  com- 
pany with  the  abductor  pollicis,  while  the  internal 
was  situated  at  the  inside  of  it,  along  with  the  ad- 
ductor and  long  flexor  tendon. 


ABNORMAL  CONDITIONS  OF  THE  HAND. 


513 


ever  keep  in  mind  a  case  given  on  the  authority 
of  Mr.  Hey,  who  informs  us  that  the  celebiated 
Mr.  Bloomfieid  reported  to  his  class  of  pupils 
at  St.  George's  Hospital,  London,  that  he  knew 
a  surgeon  increase  the  force  of  extension  to 
such  a  degree  in  attempting  reduction  of  this 
dislocation,  that  he  tore  oft'  the  thumb  at  the 
second  joint. 

The  idea  that  a  transverse  section  of  the  head 
of  the  metacarpal  bone  presents  an  outline  of  a 
cuneiform  figure  with  the  narrowest  part  of  the 
wedge  towards  the  palm,  or  forwards,  was  first 
advanced  by  Mr.  Hey,  and  has  subsequently 
been  adopted  with  too  little  reflection  by  many 
writers  :  for  our  part  we  do  not  think  that  the 
head  of  the  metacarpal  bone  does  present  this 
form  assigned  to  it  by  Hey.  But  even  al- 
though it  be  conceded  that  it  has  occasionally 
a  form  which  would  answer  to  the  description 
given  by  Mr.  Hey,  and  that  its  cuneiform 
figure  would  facilitate  its  gliding  between  the 
lateral  ligaments  and  forbid  its  return,  surely 
such  an  obstacle  to  the  return  of  the  bone 
would  suppose  a  state  of  integrity  of  both 
lateral  ligaments.  In  our  experiments  on  the 
dead  subject,  we  found  one  of  these  lateral 
ligaments  invariably  torn  whenever  a  complete 
luxation  was  effected ;  but  with  the  theory  of 
Hey,  which  seems  to  us  quite  unsupported  by 
the  normal  anatomy  of  the  bone  or  the  anatomy 
of  the  accident,  how  can  we  reconcile  the 
observation,  that  when  the  first  phalanx  of  the 
thumb  is  dislocated  to  the  palmar  instead  of 
the  dorsal  aspect  of  the  metacarpal  bone,  equal 
difficulty  of  reducing  the  luxation  has  been 
experienced  by  very  eminent  surgeons  '  For 
example,  Velpeau  says,  "  we  have  seen  but 
once  the  first  phalanx  of  the  thumb  pass  in 
front  of  the  first  metacarpal  bone.  The  sub- 
ject of  this  accident  was  a  woman  aged  forty- 
five  years;  the  bone  had  been  out  for  three 
days,  there  was  no  inflammation."  I  thought, 
says  Velpeau,  "  that  it  was  owing  to  some  want 
of  skill  in  myself  that  I  could  not  succeed  in 
reducing  the  luxation  ;  but  M.  Professor  liou- 
gon  also  made  fruitless  efforts  to  effect  it; 
finally,  M.  Roux,  with  his  well-known  address 
and  ingenuity,  was  not  more  successful,  and 
the  bone  remained  ever  afterwards  unre- 
duced."* 

Upon  the  whole  it  would  appear  to  us  that 
in  the  case  of  the  dislocation  of  the  first  pha- 
lanx of  the  thumb  on  the  dorsum  of  the  meta- 
carpal bone,  the  cause  of  the  difficulty  we  ex- 
perience in  reducing  it  will  not  be  found  either 
in  the  mechanical  resistance  of  the  lateral  liga- 
ments or  in  the  interposition  of  muscular  or 
fibrous  parts  between  the  extremities  of  the 
dislocated  bones,  but  that,  whether  the  luxa- 
tion be  the  common  one  backwards  or  the 
more  unusual  one  forwards,  thevital contraction 
of  numerous  muscles  on  a  small  and  yielding 
bone  (whose  ligaments  have  been  lacerated) 
will  be  the  principal  opposing  force  we  have  to 
contend  with.  Most  of  these  muscles  will  be 
found  to  be  favourably  circumstanced  for  the 

*   Velpeau,    Traitc   d'Anatomie    des  Regions, 
torn.  i.  p.  475,  edit.  1825. 
VOL.  I  / . 


opposition,  for  they  are  either  inserted  into  or 
attached  very  close  to  the  bones  of  the  first 
phalanx  of  the  thumb:  they  are  six  in  number; 
some  of  them  are  of  considerable  length,  and 
the  aggregate  force  of  both  long  and  short 
muscles  constitutes  a  very  powerful  means  of 
maintaining  displaced  the  first  phalanx  of  the 
thumb  ;  nor  should  it  be  forgotten,  in  estimat- 
ing their  force,  that  the  very  large  supply  of  blood- 
vessels and  nerves  which  these  muscles  receive, 
must  add  much  more  to  the  energy  of  their 
contraction  than  the  size  and  number  of  their 
composing  fibres  would  lead  us  to  suppose. 

If  such  a  view  of  the  abnormal  condition 
of  the  different  structures  which  compose  this 
articulation  be  correct,  we  should  derive  from 
it  the  important  practical  precept,  that  when 
we  have  one  of  those  difficult  cases  to  contend 
with,  our  first  effort  should  be  to  reduce,  as 
much  as  practicable,  the  irritability  and  vital 
force  of  the  muscles  which  act  on  the  dis- 
located bone  before  any  of  our  mechanical 
appliances  be  resorted  to.    When  the  general 
system  of  the  patient  has  been  under  the  de- 
pressing influence  of  the  usual  means,  viz. 
tartanzed  antimony,  &c,  and  under  these  fa- 
vourable circumstances  the  surgeon  has  with 
patience  and  perseverance  used  all  the  force 
that  he  deems  expedient  or  justifiable,  and  has 
not  succeeded  in  replacing  the  bone,  our  expe- 
rience would  induce  us  to  recommend  that  in 
such  a  case  no  further  measures  should  be  had 
recourse  to.    We  have,  in  the  museum  of  the 
Richmond  Hospital,  a  cast  of  the  hand  of  a 
man  who  had  suffered  this  luxation  sixteen 
years  before  the  cast  was  taken.    The  history 
he  gave  the  writer  was  briefly  that  he  consulted 
an  eminent  surgeon,  who  used  all  the  means  in 
his  power  to  reduce  the  dislocation,  but  could 
not  succeed;  that  the  surgeon  then  proposed 
to  the  man  an  operation  which  he  explained, 
and  which  from  the  patient's  description  of  it 
we  may  conclude  consisted  in  laying  bare  the 
head  of  the  metacarpal  bone  and  removing  it, 
as  had  been  about  that  time  recommended  by 
Mr.  Evans,  of  Kettley  near  Wellington ;  the 
man,  however,  refused  to  consent  to  the  pro- 
posal, and  had  good  reason  to  be  content  with 
his  own  determination,  as  he  can  now  oppose 
the  point  of  the  thumb  to  the  other  fingers,  and 
can  follow  his  business,  which  is  that  of  a  plas- 
terer, with  very  little  inconvenience,  affording 
us  a  proof  that  the  advice  given  by  Sir  A. 
Cooper  relative  to  irreducible  dislocations  of 
the  metacarpal  bone,  may  be  well  extended  to 
the  common  dislocation  backwards  of  the  first 
phalanx,  viz.  "  that  if  the  bone  cannot  be  re- 
duced by  simple  extension,  it  is  best  to  leave 
the  case  to  that  degree  of  recovery  which  nature 
will  in  time  produce,  rather  than  divide  the 
muscles  or  run  any  risk  of  injuring  the  nerves 
or  the  bloodvessels." 

The  first  phalanges  of  any  of  the  other  fin- 
gers may  be  luxated  backwards.  The  little 
finger  appears  to  us,  after  the  thumb,  the  most 
liable  to  this  accident ;  it  is  sometimes  difficult 
to  reduce.  Mr.  Romer,  a  pupil  of  the  Rich- 
mond Hospital,  lately  brought  to  the  writer  a 
patient  who  was  the  subject  of  luxation  of  the 

2  M 


514 


ABNORMAL  CONDITIONS  OF  THE  HAND. 


first  phalanx  of  the  little  finger  on  the  back  of 
its  metacarpal  bone.  This  patient  was  a  female 
about  thirty-five  years  of  age  ;  the  bone  had 
been  only  a  few  hours  luxated,  and  some  inef- 
fectual attempts  had  been  previously  made  to 
reduce  it.  The  reduction  was  effected  with 
some  little  difficulty  by  at  first  increasing  the 
extension,  and  then  by  forcibly  flexing  the  last 
phalanx.  In  this  case  the  long  extensor  tendon 
of  the  little  finger  was  displaced  from  its  sheath 
and  groove,  and  lay  on  the  ulnar  side  of  the 
metacarpal  bone  and  luxated  phalanx,  and 
never  afterwards  could  be  maintained  in  its 
proper  place.  This  accident  is  very  easily  re- 
cognized, yet  it  has  been  occasionally  left  un- 
reduced. 

It  has  been  stated  already  that  luxation  of 
the  first  phalanx  of  the  thumb  forwards  may 
occasionally  happen,  and  we  have  also  good 
authority  for  supposing  that  a  similar  luxation 
may  occur  to  the  phalanx  of  the  index  finger. 
These  accidents,  however,  are  very  rare ;  the 
middle,  ring,  and  little  fingers  have  never  been 
seen  thus  displaced ;  indeed,  Boyer  seems  to 
think  such  an  accident  in  these  last,  impossible 
from  the  nature  of  their  articulation  with  their 
metacarpal  bones. 

Luxation  of  the  second,  and  third  or  distal 
phalanges. — The  articulations  of  these  pha- 
langes being  only  covered  by  the  skin  and  the 
tendons  of  the  flexor  and  extensor  muscles, 
their  luxations  are  also  very  easily  recognized. 
In  the  luxation  backwards,  the  only  one  which 
we  have  had  occasion  to  observe,  the  luxated 
phalanx  is  turned  to  the  side  of  extension,  and 
forms  with  the  phalanx  above  it  an  angle  more 
or  less  open,  \\hen  it  is  the  second  phalanx 
which  is  luxated,  the  third  is  flexed  by  the 
elongation  of  the  tendon  of  the  deep  flexor, 
and  it  is  impossible  to  extend  it  or  flex  the 
second.  The  reduction  of  these  luxations  is 
generally  easy  if  time  be  not  allowed  to  elapse 
between  the  occurrence  of  the  luxation  and  the 
period  of  attempting  its  reduction. 

II.  DISEASED  CONDITIONS. 

Caries  and  necrosis  occasionally  affect  the 
bones  of  the  hand,  but  the  complete  descrip- 
tions of  these  diseases,  which  have  been  else- 
where given  in  this  work,*  render  superfluous 
here  any  special  observations  on  these  morbid 
actions  when  they  manifest  themselves  in  the 
region  of  the  hand.  The  bones  of  the  meta- 
carpus and  phalanges  are  very  frequently  de- 
formed by  a  disease  which  (although  it  cannot 
be  said  to  be  exclusively  observed  in  these 
bones)  produces  on  the  hand  and  fingers  ap- 
pearances too  remarkable  to  be  left  unnoticed 
in  this  place. 

The  disease  which  we  wish  to  describe  as  we 
have  seen  it  in  the  bones  of  the  hand  would  be 
by  some  designated  as  exostosis,!  by  others  as 
benign  osteo-sarcoma,  and  others  J  would  be 

*  See  Bone,  morbid  anatomy. 

f  See  Scarpa,  De  Anatomia  et  Pathologia  ossinm, 
cum  tabulis  aeneis,  tab.  \i.fig.  1,  Exostosis  ossiuin 
plerorumque  manus  dexterae. 

X  Boyer,  Maladies  Chirurgicales,  vol.  iii.  p.  579. 


disposed  to  preserve  the  somewhat  objection- 
able but  ancient  name  of  spina  ventosa. 

The  metacarpal  bones  and  the  phalanges  of 
the  fingers  are  the  usual  seat  of  this  disease, 
and  in  general  many  of  them  are  simulta- 
neously engaged  in  it;  the  shafts  of  the  affected 
bones  are  usually  swelled  out  by  the  disease 
into  tumours  somewhat  of  a  globular  form,  the 
articular  extremities  of  the  bones  remaining 
perfectly  free.  It  is  by  no  means  unusual  to 
see  the  first  and  second  phalanx  of  a  finger 
forming  two  distinct  globular  swellings,  while 
the  last  or  distal  phalanx  is  perfectly  free  from 
enlargement. 

It  has  been  already  mentioned  that  these 
tumours,  when  viewed  externally,  seem  to  have 
a  spheroidal  form ;  but  when  the  integuments 
of  the  bony  shell  which  incloses  the  tumours 
are  removed,  we  discover  on  their  palmar  as- 
pects the  flexor  tendons  buried  in  deep  grooves. 
This  is  of  course  best  seen  when  the  disease 
has  existed  long,  and  the  tumours  have  attained 
a  considerable  size. 

If  we  have  an  opportunity  of  examining  ana- 
tomically the  phalanges  while  the  disease  is 
yet  in  its  early  stage,  we  shall  find  reason  to 
conclude  that  the  morbid  process  had  com- 
menced deep  in  the  interior  of  the  bone,  and 
that  the  tumour  proceeding  outwardly  presented 
itself  first  on  that  aspect  of  the  phalanx,  or  me- 
tacarpal bone,  where  there  was  the  least  resist- 
ance opposed  to  it ;  hence  we  usually  notice 
these  tumours,  when  small,  shewing  themselves 
most  on  the  dorsal  aspect  of  these  bones.  As 
the  disease  increases  they  swell  out  laterally, 
and  the  whole  circumference  of  the  phalanx 
would  be  equally  expanded  were  it  not  for  the 
support  given  on  the  side  of  flexion  by  the 
flexor  tendons  and  their  strong  fibrous  sheaths. 
The  integuments  of  these  tumours  preserve  their 
natural  sensibility,  and  are  at  first  freely  move- 
able over  them  ;  but  as  the  swellings  gradually 
increase  and  undergo  a  species  of  softening  in 
certain  points,  the  integuments  become  adhe- 
rent at  these  points,  and  circular  openings  are 
formed  in  them  which  correspond  to  similar 
circular  apertures  in  the  shell  of  the  bone,  and 
through  which  the  bony  cysts  discharge  their 
contents ;  these  swellings  of  the  bones  of  the 
hand,  as  far  as  we  know,  never  degenerate  into 
any  disease  of  a  malignant  nature;  but  when 
they  attain  a  considerable  size,  and  are  exca- 
vated by  these  cysts,  and  have  large  fistulous 
orifices,  the  irritation  they  produce  and  the 
discharge  cause  some  febrile  excitement  of  the 
constitution,  and  amputation  may  become  ne- 
cessary. The  following  very  remarkable  case 
clearly  proves  the  non-malignant  nature  of  this 
disease;  the  history  of  it  will  serve  well  to  illus- 
trate the  natural  progress  of  this  form  of  dis- 
sease  in  the  hand. 

A  countryman  of  rather  a  delicate  appear- 
ance, a<jed  twenty-four  years,  was  admitted 
into  Jervis-street  Hospital,  July  22,1828,  under 
the  care  of  Dr.  O'Beirne.  This  man  had  an 
enormous  enlargement  of  the  left  hand,  which 
arose  from  a  tumour,  the  principal  seat  of  which 
was  in  the  first  and  second  phalanges  of  the 
middle  finger,  but  the  ring  and  index  finger 


ABNORMAL  CONDITIONS  OF  THE  HAND.  515 

were  also  involved  in  the  disease,  and  the  three  lignant  in  its  nature;  most  of  those  consulted 
metacarpal  bones  supporting  the  three  fingers  on  the  case  recommended  amputation,  but 
already  mentioned  were  also  much  enlarged  ;  in  Doctor  O'Beirne  conceived  the  happy  idea, 
a  word,  all  the  bones  of  the  metacarpus  and  and  speedily  put  it  into  execution,  of  cutting 
fingers,  with  the  exception  of  those  of  the  out  the  morbid  mass.  Although  it  was  rightly 
thumb  and  little  finger  viewed  externally,  conceived  that  the  index  finger  was  but  little 
seemed  to  enter  into  the  formation  of  one  mor-  diseased,  and  that  the  ring-finger  was  merely 
bid  mass,  the  size  and  form  of  which  maybe  best  enveloped  in  the  tumour,  still  the  thought  of 
conceived  by  a  reference  to  the  annexed  figure,  preserving  either  of  these  fingers  could  not  be 
The  chief  bulk  for  a  moment  entertained,  as  the  metacarpal 
Fig.  227.  of  this  large  bony    bones  supporting  them  were  known  to  be  dis- 

tumour  existed  eased.  It  was  plain  that  the  thumb  and  little 
posteriorly,  where  finger  only  could  be  saved,  and  the  lines  of 
it  extended  as  incision  which  were  followed  may  be  easily 
high  up  as  the  line  imagined.  The  operation  was  performed  thus  : 
of  the  wrist-joint,  one  incision  was  commenced  at  the  root  of  the 
and  completely  little  finger  at  its  radial  side,  which  was  ex- 
concealed  the  tended  deeply  through  the  soft  parts  upwards 
bones  of  the  car-  and  backwards  as  high  nearly  as  the  wrist-joint ; 
pus.  The  tumour  the  termination  of  this  incision  here  was  met 
did  not  extend  it-  by  another,  which  was  commenced  at  the  first 
self  directly  for-  interosseous  space  between  the  index  finger  and 
ward  towards  the  the  thumb ;  the  lines  of  these  incisions  were 
palm  of  the  hand,  followed  deeply,  and,  with  the  assistance  of  the 
but  passed  down-  knife  and  metacarpal  saw,  the  whole  of  the 
wards;  at  its  re-  morbid  mass  was  removed;  the  hemorrhage 
mote  extremity  was  soon  arrested,  and  dressings  applied  with  a 
the  last  phalanx  bandage  to  approximate  gradually  the  thumb 
of  the  middle  fin-  and  little  finger.  The  wound  was  at  first  refrac- 
ger  was  to  be  seen  tory,  and  cartilaginous  granulations  sprang  up; 
projecting ;  this  phalanx  was  itself,  however,  to  repress  these,  Dr.  O'Beirne  found  nothing 
perfectly  free  from  morbid  change,  and  the  so  effectual  as  the  actual  cautery,  and  under  its 
integuments  covering  it  possessed  their  natural  influence  the  wound  healed  kindly, 
sensibility.  The  circumference  of  the  tumour  It  is  now  nine  years  since  the  operation  was 
measured  accurately  twenty-four  inches;  nume-  performed,  and  the  man  has,  during  that  period, 
rous  very  large  protuberances  shewed  themselves  enjoyed  vigorous  health  ;  the  thumb  and  little 
every  where  on  its  surface,  which  yielded  but  finger  have  approached  each  other,  and  in- 
httle  to  pressure.  Three  of  these  tumours  had  creased  much  in  size,  power,  and  usefulness, 
ulcerated  at  their  most  prominent  points,  and  and  \he  is  fully  competent  to  fojlow  his  oc- 
by  circular  depressed  openings  (nearly  an  inch  cupation,  which  is  that  of  a  land-surveyor, 
in  diameter)  gave  exit  to  a  thin  foetid  ichorous  We  have,  in  our  collection  at  the  Richmond 
matter,  which  continued  to  flow  from  the  in-  school,  a  cast  of  this  remarkable  hand  ;  and  the 
terior  of  the  morbid  mass  These  orifices,  which  morbid  mass  which  was  removed  is  preserved 
presented  some  loose  granulations,  readily  ad-  in  the  Museum  of  the  Royal  College  of  Sur- 
mitted  the  introduction  of  a  probe,  which  could  geons,  Dublin.  A  longitudinal  section  has  been 
be  then  freely  moved  in  the  interior  of  these  made  of  the  tumour  :  one  half  has  been  sub- 
cavities,  each  of  which  was  large  enough  to  jected  to  long  maceration,  and  dried  ;  and  this 
contain  an  ordinary  hen's  egg.  The  integu-  half  exhibits  well  the  thin  osseous  shell  which 
ments  every  where  over  the  whole  of  this  mor-  encloses  the  cellular  and  reticulated  bony  struc- 
bid  growth  had  a  perfectly  healthy  aspect,  and  ture  of  the  whole  mass ; — this  portion  of  the 
were  freely  moveable  on  this  immense  tumour,  section  shews,  in  short,  the  true  structure  of  the 
except  at  the  borders  of  the  circular  apertures  bony  basis  or  skeleton  (if  we  can  so  say)  of  the 
already  mentioned.    The  disease  existed  for  disease  (fig.  228).  The 

other  half  of  the  section 
has  been  preserved  in 
spirits,  and  in  the  line  of 
division  shews  a  smooth 
cartilaginous  surface,  and 
several  excavations  lined 
by  a  smooth  membrane, 
which  had  enclosed  an 
albuminous  fluid.  Some 
of  these  cavities  were 
complete  isolated  cysts, 
buried  deep  in  the  in- 
terior of  the  cartilaginous 
mass;  but  the  contents 
of  three  of  these  cysts 
had  made  their  way  ex- 
2  m  2 


many  years,  having  begun,  as  the  patient  stated, 
when  he  was  a  boy. 

The  disease  was  unaccompanied  by  pain,  and 
the  man's  health  continued  good  until  the  pe- 
riod when  the  tumour  had  ulcerated ;  after  which 
he  became  somewhat  debilitated  by  the  exhaust- 
ing effect  of  the  sanious  discharge  on  his  con- 
stitution, and  his  mind  was  depressed  with  the 
idea  of  his  being  afflicted  with  a  disease  so 
formidable  in  appearance,  and  which  hitherto 
had  resisted,  nay  increased  under,  all  treatment, 
and  deprived  him  altogether  of  the  means  of 
earning  a  livelihood.  Although  there  was  some 
difference  of  opinion  as  to  the  name  by  which 
this  disease  of  the  bone  should  be  designated, 
it  was  agreed  that  there  was  nothing  really  ma- 


516 


ABNORMAL  CONDITIONS  OF  THE  HAND. 


ternally  through  the  large  circular  apertures 
already  mentioned. 

We  have  thought  it  right  to  detail  this  re- 
markable case  at  length,  as  it  is  the  history  of 
an  important  fact,  from  which,  it  is  true,  differ- 
ent conclusions  may  be  drawn:  for  our  part,  we 
consider  the  case  a  well-marked  specimen  of  a 
disease  described  by  some  of  the  older  writers 
as  spina  ventosa.  Boyer  adopts  this  appella- 
tion, and  in  his  work  will  be  found  a  good 
account  of  the  disease;  and,  indeed,  he  so 
accurately  depicts  the  appearances  we  observed 
in  this  case,  and  which  were  discovered  by  dis- 
section, that  we  feel  satisfied  his  description  has 
been  drawn  from  nature.  Boyer  says,  "  We 
understand  by  spina  ventosa  an  affection  of 
the  cylindrical  bones,  in  winch  the  walls  of  the 
medullary  canal  are  subjected  to  a  slow,  gra- 
dual, but  sometimes  enormous,  distension  ; 
while,  at  the  same  time,  they  are  considerably 
thinned,  and  even  pierced  in  many  points,  in 
which  their  tissue  undergoes  a  singular  rarefac- 
faction, — a  disease  whose  primitive  seat  would 
appear  to  reside  in  the  medullary  cavity,"  Sic. 

Sanson,  from  two  careful  dissections  of  recent 
specimens  of  this  disease,  considers  it  to  origi- 
nate in  a  degeneration  of  the  membrane  which 
lines  the  interior  of  the  bone.  The  substance 
which  is  found  to  fill  up  the  cavity  of  the  bone 
can  only  proceed  from  the  system  of  the  me- 
dullary membrane,  the  action  of  which  becomes 
so  altered  and  diseased,  as  to  produce  the  new 
growth  which  is  found  in  the  interior  of  these 
globular  tumours.  This  product  distends  by 
degrees  the  walls  of  the  medullary  canal  and 
reticular  structure  of  the  bones.  The  dilatation, 
in  which  the  articular  surfaces  do  not  partici- 
pate, is  generally  sudden,  so  that  the  part  imme- 
diately near  the  point  where  the  disease  is 
situated  preserves  its  natural  dimensions  When 
the  globular  tumours  thus  formed  are  cut  into, 
in  the  early  stage  of  the  affection,  their  interior 
presents  a  fibro-cartilaginous  appearance,  sur- 
rounded by  a  thin  shell  of  bone.  A  section 
of  one  of  those  tumours  of  the  fingers  in  the 
early  stage  appears  to  us  to  present  a  striking 
resemblance  to  the  common  fibrous  tumour  of 
the  uterus,  which  is  often  encased  in  a  similar 
bony  shell.  The  description  Mr.  Crampton 
has  given  of  the  structure  of  the  benign  osteo- 
sarcoma may  well  be  applied  to  this  disease. 
He  says,  "  the  interior  of  the  tumour  presents 
a  great  variety  of  structure,  but  I  should  say, 
in  general,  that  the  cartilaginous  character  which 
the  tumour  exhibits  in  its  origin  prevails  to  the 
last.  In  the  early  stages  of  the  disease,  the 
tumour  consists  of  a  dense  elastic  substance, 
resembling  fibro-cartilaginous  structure ;  but 
the  resemblance  is  more  in  colour  than  in  con- 
sistency, for  it  is  not  nearly  so  hard,  and  it  is 
granular  rather  than  fibrous,  so  that  it  breaks 
short.  On  cutting  into  the  tumour,  the  edge  of 
the  knife  grates  against  spiculse,  or  small  grains 
of  earthy  matter  with  which  the  substance  is 
beset.  If  the  tumour  acquires  any  considerable 
size,  it  is  usually  found  to  contain  cavities  filled 
with  a  fluid  differing  in  colour  and  consistency  ; 
but  in  general  the  fluid  is  thickish,  inodorous, 
and  of  the  colour  of  chocolate.    Sometimes  the 


growth  of  the  tumour,  and  the  secretion  of  the 
fluid  within  its  substance,  is  so  slow,  that  the 
deposition  of  bony  matter  keeping  pace  with 
the  absorption,  the  bone  becomes  expanded  into 
a  large  thick  bony  case,  in  which  the  tumour  is 
completely  enclosed."* 

Sti'innous  osteitis  of  the  metacarpal  bones,  and 
of  the  phalanges  of  the  fingers. — It  is  by  no 
means  difficult  to  distinguish  the  disease  last 
described  under  the  name  of  spina  ventosa,  or 
benign  osteo-sarcoma,  from  that  enlargement  of 
tiie  metacarpal  bones  and  of  the  fingers  which  we 
frequently  witness  in  children  of  the  strumous 
diathesis.  The  strumous  affection  of  the  pha- 
langes we  allude  to  seems  little  else  than  an 
osteitis,  which  terminates  usually  either  in  caries 
or  necrosis.  The  disease,  when  fully  formed, 
shows  itself  in  the  shape  of  either  a  pyriform 
or  globular  swelling  of  the  phalanx  of  one  or 
more  of  the  fingers.  There  is  at  first  no  sensi- 
ble alteration  of  the  surrounding  soft  parts  ;  the 
swelling  has  usually  been  preceded  by  pains 
of  a  dull  and  obtuse  character ;  the  movements 
of  the  part  affected  are  for  a  long  time  preserved, 
and  indeed  are  not  at  all  restrained,  except 
when  the  tumefaction  of  the  bone  becomes 
sufficient  to  turn  aside  the  tendons  from  their 
natural  direction,  or  to  cause  deformity  of  the 
articular  surfaces,  which  rarely  happens. 

As  the  disease  advances,  the  soft  parts  are 
distended,  suppuration  takes  place,  and  the 
integuments  of  the  swollen  part  always  ulcerate 
at  a  point  corresponding  to  some  deficient  part 
of  the  bony  cylinder.  Through  the  ulcerated 
opening  a  probe  may  be  passed  freely  into  a 
cavity  which  the  bone  contains;  the  opening 
becomes  fistulous,  and  for  a  long  time  continues 
to  give  exit  to  a  moderate  quantity  of  thin, 
serous,  and  ill-conditioned  matter ;  sometimes, 
however,  we  notice  an  improvement  in  the  ge- 
neral health  of  the  patient,  and,  at  the  same 
time,  the  local  disease  assumes  a  new  and  more 
favourable  aspect,  the  discharge  diminishes,  and 
at  length  dries  up.  Such  a  decided  amendment, 
however,  seldom  occurs,  until  a  process  of  ne- 
crosis, or  exfoliation  of  a  part  of  the  bone,  has 
taken  place;  after  which  the  wound  heals  up, 
the  use  of  the  finger  is  restored,  and  all  that 
remains  of  the  disease  is  an  unseemly,  depressed, 
and  adherent  cicatrix. 

Malignant  tumours  of  the  hand. — Malignant 
osteo-sarcoma,  and  even  fungus  haematodes,  are 
diseases  which  may  show  themselves  in  the 
region  of  the  hand  and  fingers ;  but  these  dis- 
eases are  readily  distinguished  from  the  spina 
ventosa,  or  benign  osteo-sarcoma,  above  alluded 
to.  The  pains  of  tiie  malignant  disease  are 
lancinating,  the  progress  is  more  acute,  the  con- 
stitution and  health  are  more  quickly  and  deeply 
implicated  ;  the  prognosis,  too,  is  very  different. 
Although  life  may  perhaps  be  prolonged  by  an 
amputation  of  the  hand  of  a  patient  affected 
by  either  of  these  malignant  diseases,  the  terri- 
ble disorder  will  almost  uniformly  recur.  On 
the  contrary,  if  the  disease  be  spina  ventosa,  a 
portion  of  the  hand  may  be  amputated,  or  a 
finger  removed,  and  the  disease  shall  not  recur 

*  Vide  Dublin  Hospiial  Reports,  vol.  iv.  p.  542. 


ABNORMAL  CONDITIONS  OF  THE  HAND. 


517 


after  these  operations.     Indeed,  we  feel  per- 
suaded that,  in  some  cases  of  spina  ventosa, 
(fig.  229)   the  tumour  may  be  cut  off  from 
a  finger  or  from  a  me- 
Fig.  229.  tacarpal  bone,  and  that 

although  the  wound 
may  for  a  while  throw 
up  cartilaginous  gra- 
nulations, still,  under 
proper  treatment,  the 
ulcer  of  the  bone  will 
be  got  to  heal  kindly. 

Abnormalconditions 
of  the  fingers  the  re- 
sult of  accidents  and 
morbid  affect  ions  of  one 
or  more  of  their  consti- 
tuent structures. — We 
occasionally  find  that 
the  voluntary  power  of 
flexing  orextendingthe 
joints  of  the  fingers  is 
lost.  This  loss  of 
power  may  arise  from 
a  great  variety  of 
causes; — anchylosis  of  a  joint  from  acute 
or  chronic  inflammation;  the  loss  of  an  ex- 
tensor or  flexor  tendon  from  a  similar  cause, 
or  from  a  wound;  congenital  malformation  of 
the  brain;  disease  or  accident  affecting  this 
organ,  the  spinal  marrow,  or  the  nerves  con- 
nected with  the  movements  of  the  upper  extre- 
mity;  any  of  these  may  at  times  be  the  source 
of  this  loss  of  the  voluntary  power  over  the 
fingers.  Under  these  circumstances,  although 
there  may  be  but  little  external  deformity, 
sometimes  the  fingers  cannot  be  flexed ;  more 
frequently  they  cannot  be  voluntarily  extended. 
An  abnormal  condition  of  the  fingers,  shewing 
itself  in  some  distortion  of  these  organs,  may 
be  traced  to  causes  affecting — 1,  the  skin;  2, 
the  fascia;  3,  the  theca  of  the  tendons;  4,  the 
tendon  itself;  and  .5,  the  bone.  If  a  burn  pe- 
netrate the  skin  on  the  palmar  surface  of  the 
hand,  a  dense  cicatrix  will  be  formed ;  and  much 
exertion  will  be  necessary,  on  the  part  of  the 
surgeon,  to  oppose  successfully  the  gradual  con- 
traction of  the  "  tissue  of  the  cicatrix."  Should 
contraction  take  place,  notwithstanding  these 
efforts,  the  functions  of  the  hand  will  be  im- 
paired, and  much  deformity  will  remain.  A 
burn  on  the  back  of  the  hand  may  be  followed 
by  analogous  effects. 

There  is  a  peculiar  form  of  contraction  of 
the  fingers,  which  Boyer  seems  to  ascribe  (we 
believe  erroneously)  to  a  shortening  of  the  ten- 
dons. Adopting  the  language  of  the  ancients, 
he  denominates  the  affection  "crispatura  tendi- 
num."  This  contraction  of  the  fingers  is  never 
seen  in  very  young  persons.  Most  of  those 
we  have  known  affected  by  it  were  adults,  who 
had  been  for  a  long  time  compelled  to  make 
laborious  use  of  their  hands.  The  disease  will 
be  ordinarily  found  to  commence  in  a  contrac- 
tion of  the  little  finger;  the  ring  finger  is  next 
engaged,  and  then  the  middle  finger.  From 
day  to  day  the  fingers  become  more  contracted, 
and  the  power  of  extending  them  is  lost.  When 
one  hand  is  thus  affected,  it  usually  happens 


that  the  other  soon  becomes  equally  engaged. 
It  is  remarkable  that  neither  the  indicator  nor 
the  thumb  have  ever  been  seen  affected  with 
this  disease. 

When  we  examine  the  fingers  the  subjects  of 
this  species  of  contraction  (fig.  230),  we  find 
that  the  first  phalanx  is  moveable  on  the  meta- 
carpal bone,  and  is  flexed  at  an  angle  more  or 
less  approaching  to  a  right  angle.  We  can  flex 
it  a  little  more  towards  the  palm;  but  to  extend 
it  so  as  to  efface  the  angle  is  impossible;  "a 
weight,"  says  Dupuytren,  "of  150lbs.  will  not 
bring  the  finger  into  a  straight  line  with  its  me- 
tacarpal bone."  Boyer  says,  "our  efforts  to 
extend  the  fingers  are  resisted  to  such  a  degree, 
that  if  we  continued  them  they  would  break 
before  we  could  force  them  to  yield." 


Contraction  of  the  Jin  yers  from  disease  of  the  palmar 
fascia. 

This  description,  however,  applies  only  to  the 
metacarpal  joint  of  the  first  phalanx,  for  the  last 
phalanges  of  each  affected  finger,  though  move- 
able, habitually  remain  perfectly  straight. 

In  these  cases  the  integuments  of  the  affected 
palm  and  the  subjacent  fascia  seem  to  be  more 
than  naturally  thick  and  consolidated,  and  we 
observe  the  lowest  of  the  natural  cutaneous 
lines  of  the  palm  thrown  into  a  very  deep 
crescentic  fold,  the  concavity  of  which  looks 
towards  the  fingers,  and  the  convexity  towards 
the  wrist  joint.  We  also  invariably  notice  in 
these  cases  a  rounded  projecting  chord  which 
passes  downwards  from  the  middle  of  the 
palm  of  the  hand  to  the  basis  of  the  first 
phalanx  of  the  contracted  finger.  This  chord 
feels  hard,  and  is  rendered  more  tense  and 
salient  whenever  we  make  an  effort  to  straighten 
the  affected  finger. 

When  in  the  living  subject  we  examine  care- 
fully the  palmar  fascia,  and  explore,  as  far  as 
we  can,  its  connexion  above  with  the  tendon  of 
the  pal  maris  lorigus,  and  below,  follow  the  pro- 
longations it  sends  to  the  lateral  aspect  of  the 
contracted  fingers,  we  find  them  all  continuous; 
in  a  word,  when  we  press  upon  the  tendon  of 
thepalmaris  longus,  we  maketensethetendinous 
digitations  above-mentioned.  The  continuity 
of  all  these  fibrous  structures  is  thus  evident  in 


518 


ABNORMAL  CONDITIONS  OF  THE  HAND. 


the  living.  When  we  have  opportunities  of 
examining,  in  the  dead  subject,  a  hand  in  wnich 
tins  contraction  of  the  palmar  aponeurosis  has 
existed,  and  have  raised  the  skin  in  all  its  ex- 
tent from  the  palm  of  the  hand  and  palmar  sur- 
face of  the  fingers,  its  folds  and  ruga;  all  dis- 
appear, and  it  then  becomes  evident  that  this 
defect  does  not  reside  in  the  skin.  When  the 
aponeurosis  is  exposed,  it  is  found  contracted, 
thickened,  and  diminished  in  length.  From  its 
inferior  part,  the  tense  fibrous  chords  which 
were  already  supposed  to  exist  are  now  exposed, 
and  seen  to  be  inserted  into  the  periosteum  on 
the  lateral  aspects  of  the  contracted  finger. 

Dupuytren,  by  various  anatomical  and  pa- 
thological investigations  of  this  disease,  satisfied 
himself  that  this  peculiar  contraction  of  the 
fingers  depends  essentially  on  this  shortening, 
thickening,  and  organic  alteration  of  the  palmar 
aponeurosis  and  the  digitations  proceeding  from  it 
to  the  sidesof  the  fingers ;  for  he  invariably  found 
when  he  had  opportunities  of  investigating  this 
disease  in  the  dead  subject,  that  the  tendons 
were  of  their  accustomed  volume  and  mobility. 
He  cut  them  across,  and  then  made  efforts  in 
vain  to  extend  the  finger.  The  bones  were 
found  of  their  natural  form,  and  no  alteration 
was  perceptible  in  either  the  synovial  mem- 
branes or  lateral  ligaments;  but  as  soon  as  the 
section  of  the  expansions  of  the  fascia  which  go 
to  the  fingers  was  effected,  the  flexion  dis- 
appeared, and  the  finger  could  be  brought  to 
its  normal  position.  Finally,  he  infers,  and 
indeed,  as  far  as  a  few  instances  go,  he  proves, 
that  a  similar  result  will  follow  the  division  of 
the  fascia  in  the  living  subject,  and  that  the 
proper  use  and  adjustment  of  a  peculiar  splint 
on  the  back  of  the  forearm  and  hand,  so  as  to 
keep  the  affected  fingers  for  a  time  extended, 
will  complete  the  cure  of  this  disease. 

Sir  A.  Cooper  alludes  to  these  deformities 
when  he  says,  "  The  fingers  are  sometimes  con- 
tracted by  a  chronic  inflammation  of  the  theca 
and  aponeurosis  of  the  palm  of  the  hand,  from 
excessive  action  of  the  hand  in  the  use  of  the 
hammer,  the  oar,  ploughing,  &c,"  evidently 
recognising  two  species,  in  one  of  which  the 
aponeurosis  is  the  cause  of  the  contraction,  and 
the  contracted  hand  is  narrow.  "  And  this 
hand,"  he  adds,  "  may  with  advantage  be  di- 
vided by  a  pointed  bistoury,  introduced  through 
a  small  wound  in  the  integuments ;  the  finger 
may  be  then  extended,  and  a  splint  applied  to 
preserve  it  in  the  straight  position."  But  he 
observes  that  "  where  the  theca  is  contracted, 
nothing  should  be  attempted  for  the  patient's 
relief,  as  no  operation  or  other  means  have  suc- 
ceeded." 

Anchylosis  of  some  of  the  joints  of  the 
phalanges  sometimes  succeeds  to  an  attack  of 
acute  or  chronic  inflammation  of  one  or  more 
of  these  small  articulations;  this  may  have 
arisen  from  disease;  for  example,  paronychia  or 
accident;  but  from  whatever  cause  the  inflam- 
mation has  arisen,  anchylosis  of  a  finger  in  the 
extended  position,  which  cannot  be  contracted, 
or  of  a  joint  in  the  flexed  position,  which  can- 
not be  extended,  is  the  too  frequent  result.  The 
history  of  the  case,  and  the  actual  state  of  the 


anchylosed  joint,  which  cannot  be  overlooked, 
will  prevent  the  surgeon  from  falling  into  any 
eiror  in  his  diagnosis.  A  contracted  state  of 
the  ring  finger  and  little  finger  is  frequently  to 
be  noticed  in  those  who  have  suffered  much 
from  gout;  but  we  are  acquainted  with  no  dis- 
ease which  more  frequently  produces  deformity 
of  the  hand  and  fingers  than  chronic  rheumu- 
tism  (chronic  rheumatic  arthritis).  This  mor- 
bid condition  of  the  joints  of  the  hand  is  too 
cursorily  alluded  to  by  authors  under  the  head 
of  rheumatic  gout,  nodosity  of  the  joints  of  the 
fingers,  &c.  &c.  It  is  a  complaint  which  is  erro- 
neously supposed  to  be  met  with  only  in  elderly 
persons.  We  have,  however,  in  the  pauper  de- 
partment of  the  House  of  Industry  in  Dublin, 
examples  of  it  in  females  under  the  age  of  30; 
but  of  course  it  is  more  frequently  observed  in 
the  aged  and  rheumatic  patient.  When  the 
disease  has  existed  long,  the  whole  hand  be- 
comes greatly  deformed,  and  the  distortion  the 
fingers  have  undergone  in  these  cases  is  of  it- 
self calculated  to  impress  us  with  a  correct  idea 
of  the  sufferings  the  victims  of  this  disease 
have  endured.  The  carpus  is  usually  preter- 
naturally  convex  on  its  dorsal  aspect,  owing  to 
the  thickening  and  distension  of  the  synovial 
bursa?,  which  become  like  solid  ganglions.  All 
the  joints  of  the  hand  and  fingers  become  en- 
larged, particularly  those  which  are  formed  by 
the  junction  of  the  first  phalanges  and  metacar- 
pal bones;  at  these  joints  the  fingers  are  more 
or  less  flexed  towards  the  palm,  and  are,  at  the 
same  time,  adducted  or  drawn  to  the  ulnar  side 
of  the  hand. 

The  head  of  the  metacarpal  bone,  where  it 
joins  with  the  first  phalanx  of  the  index  finger, 
seems  particularly  swelled  and  enlarged,  and 
projects  much  towards  the  radial  side  and  dor- 
sal aspect  of  the  hand,  as  is  represented  in^g. 
231. 


Fig.  231. 


Chronic  rheumatism,  or  nodosity  of  the  joints. 

The  last  phalanx  of  a  finger  is  frequently 
flexed,  while  the  middle  phalanx  is  extended. 
Whatever  be  the  faulty  position  which  the  fin- 
gers happen  to  have  assumed,  they  are  usually 
found  to  be  remarkably  rigid.    All  movements 


MUSCLES  OF  THE  HAND. 


519 


of  them,  whether  voluntary  or  communicated 
to  them,  are  painful ;  and  in  either  case  com- 
monly a  crepitus,  produced  by  the  contact  of 
rough  surfaces,  is  perceived  both  by  patient 
and  physician  when  making  the  examination. 

When  this  disease  exists  in  the  hand  to  this 
amount,  it  will  almost  invariably  be  found  that 
the  distressing  complaint  has  also  extensively 
engaged  most  of  the  other  articulations. 

When  we  make  an  anatomical  examination 
of  the  hand  of  those  who  have  died  with  the 
condition  of  the  joints  of  the  fingers  above 
described,  we  find  that  the  synovial  fluid  is 
somewhat  thicker  than  usual,  and  deficient  in 
quantity.  In  some  of  the  anchylosed  joints  we 
observe  a  species  of  fibro-cellular  or  ligamentous 
union  of  the  bones;  almost  all  the  joints  are  de- 
prived of  their  cartilaginous  incrustation,  which 
seems  as  it  were  to  have  been  worn  away  by 
friction  ;  the  porous  structure  of  the  root  of  the 
phalanges  is  often  exposed,  and  in  some  cases 
hollowed  out,  to  accommodate  the  enlarged 
head  of  the  metacarpal  bone  ;  a  cup  is  formed  in 
the  base  of  the  phalanx  which  is  lined  with  a 
porcelainous  deposit,  while  around  this  little 
cup  an  exuberant  growth  of  new  bone  of  a 
looser  texture  is  thrown  out.  In  the  removal 
of  the  cartilage  without  suppuration — in  the 
substitution  for  it  of  a  porcelain-like  deposit, 
and  in  the  surrounding  exuberance  of  new 
bone,  we  find  this  disease  of  nodosity  of  the 
joints  of  the  fingers  resembling  accurately  the 
analogous  affection  of  the  other  joints,  which 
has  been  supposed  to  be  the  slow  effects  of 
chronic  rheumatism.- — See  Elbow,  Knee,  Hip, 
Abnormal  Anatomy  of. 

III.  congenital  malformations  of  the 

HAND. 

Children  are  occasionally  bom  with  one  or 
two  fingers  more  than  the  natural  number.  The 
supernumerary  finger  almost  invariably  is  found 
to  be  an  imperfect  vegetation,  growing  from  the 
ulnar  side  of  the  hand,  and  in  general  the 
deformity  is  found  to  exist  on  both  hands. 
Examples,  however,  have  been,  though  rarely, 
seen  of  a  sixth  finger  parallel  to  the  other  fin- 
gers, and  properly  supported  by  a  sixth  meta- 
carpal bone. 

It  frequently  happens  that  children  are 
brought  into  the  world  with  their  fingers  united 
together.  This  union  may  be  complete,  or  the 
connexion  may  be  loose  by  means  of  the  skin. 
It  is  known  that  up  to  the  second  or  third  month 
of  intra-uterine  life  an  interdigital  membrane 
exists,  and  the  abnormal  condition  of  the  fin- 
gers we  are  now  considering  is  nothing 
but  a  persistence  of  the  early  condition 
of  the  fingers  in  the  foetal  state.  It  seems 
pretty  well  proved  that  these  congenital  defects 
are  very  frequently  hereditary,  and  that  when- 
ever the  fingers  are  the  seat  of  them,  the  toes 
are  similarly  affected. 

The  whole  hand,  or  one  or  more  of  the  fin- 
gers may  suffer  in  utero  what  has  been  denomi- 
nated spontaneous  amputation,  and  the  stump 
will  present  peculiarities  already  noticed. — See 
Foetus,  fig.  155,  159. 

(  R.  Adams.) 


HAND,  MUSCLES  OF  THE.  (Human 
Anatomy.)  The  varied  and  beautiful  move- 
ments of  which  the  hand  is  capable  are  effected 
by  muscles  belonging  to  separate  and  distinct 
regions,- — namely,  one  set  of  muscles  which  are 
the  proper  and  intrinsic  muscles  of  the  hand 
itself,  and  a  second  set,  which  are  continued  into 
the  dorsal  or  palmar  region  of  the  hand  from 
the  posterior  or  anterior  surface  of  the  fore-arm. 
In  the  present  article  it  is  proposed  to  describe 
the  intrinsic  muscles  of  the  hand ;  but  in  con- 
sidering the  actions  of  that  member  or  of  any 
of  its  segments,  it  will  be  necessary  to  notice 
how  far  the  second  set  of  muscles  contribute  to 
or  aid  in  their  production. 

The  proper  or  intrinsic  muscles  of  the  hand 
may  be  divided  into — 1,  those  on  the  palmar; 
2,  those  on  the  dorsal  surface. 

I.  The  muscles  of  the  palm  are  fifteen  in 
all.  For  convenience  of  description  they  may 
be  classified  into,  a,  those  of  the  thumb,  or 
external  palmar  region,  constituting  the  thenar 
eminence;  b,  those  of  the  little  finger,  or  in- 
ternal palmar  region,  forming  the  hi/pothenar 
eminence;  c,  those  that  occupy  the  hollow  of 
the  hand,  or  the  middle  palmar  region. 

a.  Muscles  of  the  external  palmar  region. — 
The  muscles  of  this  region,  all  of  which  belong 
to  the  thumb,  are  four. 

1.  Abductor  polltcis  manus*  (scaphoido- 
phalangien,  Cruveilh  )  short,  flat,  broader  above 
than  below;  it  arises  from  the  anterior  surface 
of  the  scaphoid  and  trapezium,  the  superior, 
anterior,  and  external  part  of  the  anterior  annu- 
lar ligament,  and  generally  from  a  prolongation 
of  the  tendon  of  the  extensor  ossis  metacarpi, 
by  aponeurotic  and  fleshy  fibres.  It  proceeds 
outwards  and  downwards  to  be  inserted  into 
the  outer  edge  of  the  upper  extremity  of  the 
first  phalanx  of  the  thumb.  Sometimes  the 
two  origins  of  this  muscle  are  not  incorporated 
tor  some  distance,  giving  the  appearance  of 
two  muscles. 

Relations.- — It  is  covered  by  the  skin  and 
external  palmar  aponeurosis.  It  covers  the 
opponens,  a  few  fibres  of  which  appear  to  its 
radial  side,  running  in  a  transverse  direction. 
It  is  separated  by  a  thin  cellular  line  from  the 
short  flexor,  which  is  on  the  same  plane. 

The  obvious  action  of  this  muscle  is  to  draw 
the  thumb  forwards  and  inwards,  thus  sepa- 
rating it  from  the  fingers. 

2.  Flexor  ossis  metacarpi,  or  opponens  polli- 
cis  (trapezo-metacarpien,  Cruveilh.),  of  a 
rhomboidal  form  ;  it  arises  from  the  trapezium, 
and  from  the  fore  part  of  the  anterior  annular 
ligament,  anterior  to  the  sheath  for  the  radial 
flexor  of  the  wrist,  by  long  aponeurotic  fibres ; 
and  posteriorly  from  a  septum  between  it  and 
the  short  flexor.  From  these  attachments  the 
fleshy  fibres  radiate  downwards  and  outwards, 
being  so  much  the  shorter  the  higher  and  the 
more  transverse  they  are.    They  terminate  by 

*  Soemmering  and  Albinus  divide  tins  into  two 
distinct  muscles,  the  former  giving  them  the  names 
ahductores  breves  polltcis  manus  interior  et  exterior  ; 
the  latter  calls  the  internal  portion  abductor  brevis 
alter. 


520 


MUSCLES  OF  THE  HAND. 


short  aponeuroses  along  all  the  outer  edge  of 
the  first  metacarpal  bone. 

Relations. — With  the  exception  of  a  small 
portion  of  its  external  border,  this  muscle  is 
covered  anteriorly  by  the  preceding  muscle.  It 
covers  the  anterior  surface  of  the  first  meta- 
carpal bone,  and  its  articulation  with  the  tra- 
pezium. 

It  draws  the  thumb  inwards,  turning  it  upon 
its  own  axis,  so  that  it  opposes  its  palmar 
aspect  to  the  other  ringers. 

3.  Flexor  brevis  pollicis  manus  (trapezo- 
phalangien,  Cruveilh.)  is  a  larger  muscle  than 
the  two  preceding  ones,  triangular,  bifid  supe- 
riorly, having  its  anterior  surface  channelled ; 
arises  by  aponeurotic  and  fleshy  fibres,  exter- 
nally from  the  fore  and  under  part  of  the 
annular  ligament,  and  from  the  process  of  the 
trapezium,  internally  and  posteriorly  from  all 
the  reflected  portion  of  the  annular  ligament, 
forming  the  sheath  for  the  radial  flexor  and 
extending  to  the  os  magnum,  and  from  the  os 
magnum  often  by  a  distinct  portion.  From  these 
various  origins  the  fleshy  fibres  run  downwards 
and  outwards,  are  more  oblique  as  they  are 
more  internal,  and  terminate  in  a  strong  fleshy 
bundle  which  is  attached  to  the  external  sesa- 
moid bone  and  outer  side  of  the  first  phalanx. 

Relations. — This  muscle  is  covered  by  the 
external  palmar  aponeurosis,  more  internally  by 
the  tendon  of  the  long  flexor  of  the  thumb,  then 
by  the  common  flexor  tendons.  It  covers  the 
first  dorsal  interosseous,  the  tendon  of  the 
radial  flexor  of  the  wrist,  and  a  small  portion 
of  the  external  margin  of  the  adductor  of  the 
thumb.  Its  outer  edge  corresponds  to  the 
abductor  and  is  often  confounded  with  the 
opponens,  and  its  inner  would  be  undistin- 
guishable  from  the  abductor  near  the  first  meta- 
carpal bone,  if  it  were  not  separated  from  it  by 
the  arteria  magna  pollicis,* — a  fact  that  appears 
to  have  been  overlooked  by  many  anatomists, 
or  the  descriptions  of  the  attachments  of  this 
muscle  would  never  have  been  so  much  at 
variance:  the  foregoing  description  coincides 
with  that  of  Meckel  and  Cruveilhier.  Its 
tendon  of  insertion  is  covered  by  that  of  the 
abductor,  which  is  external  to  it. 

This  muscle  is  badly  named,  at  least  if 
names  be  intended  to  denote  action,  for  its 
power  of  flexing  the  thumb  is  very  slight;  but 
it  has  considerable  power  as  an  opposer  of  it, 
its  insertion  being  especially  favourable  to  that 
action. 

4.  Adductor  pollicis  manus  (metacarpo-pha- 
langien  dupouce,  Chauss.)  is  the  largest  muscle 
of  the  thumb  as  well  as  the  most  internal ;  in 
shape  it  is  a  perfect  triangle,  arising  from  all 
the  anterior  border  of  the  third  metacarpal 
bone,  from  its  articulation  with  the  magnum, 
from  the  anterior  and  superior  portion  of  the 
trapezoid,  and  from  the  palmar  interosseous 
aponeurosis  in  its  central  portion.  From  this 
extensive  attachment  the  fibres  run  transversely 
outwards,  the  superior  ones  being  most  oblique; 
they  converge  to  a  strong  fleshy  bundle,  which 

*  Also  deep  in  the  palm,  it  is  generally  sepa- 
rated from  the  adductor  by  the  deep  palmar  arch. 


is  inserted  by  means  of  the  internal  sesamoid 
bone  into  the  first  phalanx  of  the  thumb. 

Relations. — Its  two  internal  thirds  are  covered 
by  the  lumbricales  and  common  flexor  tendons, 
also  by  a  layer  of  the  deep  interosseous  apo- 
neurosis which  constitutes  its  sheath.  It  covers 
the  two  first  interosseous  spaces.  Its  inferior 
border  is  subcutaneous,  especially  posteriorly, 
where  it  may  be  felt  in  the  fold  of  skin  extend- 
ing from  the  index  finger  to  the  thumb.* 

Its  name  implies  its  action ;  it  draws  the 
thumb  towards  the  median  line  of  the  hand. 

b.  Muscles  of  the  internal  palmar  region. — 
There  are  four  muscles  in  this  region  also;  one 
is  a  cutaneous  muscle,  the  palmaris  brevis ;  the 
others  are  proper  to  the  little  finger,  and  are 
inserted  into  the  inner  side  of  its  first  phalanx 
and  the  fifth  metacarpal  bone.  They  consist, 
as  the  last  described  set,  of  an  abductor,  short 
flexor,  and  an  opponens  minimi  digiti. 

1.  Palmaris  brevis  (peaucier  de.  la  main, 
Cruveilh.)  This  muscle  when  it  exists,  (for  in 
weakly  subjects  its  fibres  are  often  not  to  be 
distinguished,  though  on  the  other  hand  it 
acquires  considerable  volume  in  those  that  are 
muscular,)  arises  by  aponeurotic  intermingled 
with  fleshy  fasciculi  which  run  horizontally 
inwards,  forming  a  small  quadrilateral  muscle 
which  terminates  in  the  skin. 

Relations. — Covered  by  the  skin  and  im- 
bedded in  the  adipose  substance,  it  is  spread 
over  the  muscles  of  the  little  finger  and  the 
ulnar  artery  and  nerve,  from  which  it  is  sepa- 
rated by  the  internal  palmar  aponeurosis. 

It  increases  the  concavity  of  the  palm  by 
puckering  the  skin  over  the  part  it  occupies, 
thereby  drawing  the  hypothenar  eminence  for- 
wards and  outwards,  and  rendering  it  more 
convex. 

2.  Abductor  minimi  digiti  (pisi-phalangien, 
Cruveilh.)  A  long  flat  muscle,  broadest  at  its 
centre,  arising  from  the  pisiform  bone  and  from 
an  expansion  of  the  flexor  carpi  ulnaris,  by 
strong  aponeurotic  fibres,  which  soon  become 
fleshy,  running  along  the  inner  edge  of  the 
fifth  "metacarpal  bone.  It  ends  in  a  flattened 
tendon,  which  is  inserted  in  common  with  the 
short  flexor  into  the  inner  side  of  the  first 
phalanx,  sending  an  expansion  into  the  extensor 
tendon. 

Relations. — It  is  covered  by  the  internal 
palmar  aponeurosis,  itself  covering  the  oppo- 
nens. 

Jjse, — Jt  draws  the  little  finger  inwards  and 
forwards,  separating  it  from  the  others. 

*  Sometimes  this  muscle  is  separated  into  two 
bellies,  the  one  superior  and  the  other  inferior, 
which  are  completely  separate  from  each  other, 
and  of  which  the  superior  is  by  far  the  greater.  Ill 
this  case  the  first  arises  solely  from  the  os  magnum 
or  from  this  bone  and  a  small  portion  of  the 
superior  extremity  of  the  third  metacarpal  bone, 
while  the  second  arises  from  the  inferior  portion  of 
the  anterior  head  of  the  third,  fourth,  and  some- 
times even  the  fifth  metacarpal  bones;  it  runs 
transversely  outwards  and  a  little  backwards  to 
meet  the  superior  head  at  the  first  phalanx  of  the 
thumb.  This  anomaly  resembles  the  normal  con- 
dition of  the  transverse  and  oblique  adductors  of 
the  great  toe.    Meckel,  Anat.  vol.  ii.  p.  185. 


MUSCLES  OF  THE  HAND.  521 


3.  Flexor  brevis  minimi  digiti  (  unci-plialan- 
gien,  Cruveilh.) — This  muscle  is  external  to  the 
Jast;  it  arises  from  a  small  portion  of  the  annu- 
lar ligament  and  from  the  anterior  part  of  the 
unciform  process  ;  it  runs  downwards  and  in- 
wards to  join  the  last  described  muscle,  with 
which  it  is  inserted. 

Relations. — At  its  origin  it  is  separated  from 
the  abductor  by  the  ulnar  vessels  and  nerve, 
but  it  soon  becomes  confounded  with  it. 
Chaussier  described  them  both  as  one  muscle. 
It  is  often  wanting.  In  concert  with  the  last, 
it  abducts  and  slightly  flexes  the  little  finger. 

4.  Adductor  ossis  metucurpi  or  opponens 
minimi  digiti  (unci-metacarpien,  Cruveilh.) — It 
resembles  in  disposition  and  form  the  opponens 
pollicis.  Having  the  same  origins  with  the 
preceding  muscle,  its  fibres  proceed  downwards 
and  inwards,  the  superior  being  nearly  hori- 
zontal ;  they  are  inserted  into  all  the  internal 
border  of  the  fifth  metacarpal  bone. 

Relations. — It  is  covered  by  the  two  last 
muscles;  its  posterior  surface  is  applied  to  the 
fifth  metacarpal  bone,  the  corresponding  inter- 
osseous, and  the  tendon  of  the  flexor  sublimis 
going  to  the  little  finger. 

It  carries  the  fifth  metacarpal  bone  forwards 
and  outwards,  thereby  augmenting  the  cavity 
of  the  hand,  and  in  a  measure  opposing  the 
little  finger  to  the  thumb,  but  the  articulation 
of  the  metacarpal  bone  with  the  us  unciforme 
allows  of  so  very  little  rotatory  motion,  that  it 
is  rather  a  motion  of  adduction  and  flexion 
than  of  opposition. 

c.  Muscles  of  the  middle  putmar  region. — 
In  the  middle  palmar  region  we  have  seven 
muscles,  four  connected  to  the  tendons  of  the 
flexor  profundus,  the  lumbricales,  so  called 
from  their  resemblance  to  earth-worms ;  and 
three  deeper-seated  muscles,  the  palmar  inter- 
ossei  occupying  a  part  of  the  second,  third,  and 
fourth  interosseous  spaces  between  the  meta- 
carpal bones,  the  remaining  part  of  those  spaces 
being  filled  up  by  muscles  ;  we  shall  presently 
examine  the  dorsal  interossei. 

1.  Lumbricales  (ficctentes  primum  interno- 
dium,  Spig.)  are  four  slender,  elongated,  fusi- 
form, fleshy  bundles,  attached  to  the  tendons  of 
the  flexor  profundus,  just  after  it  escapes  from 
under  the  annular  ligament,  distinguished  into 
first,  second,  &c.  from  without  inwards.  The 
first  arises  from  the  fore  and  outer  part  of  the 
flexor  profundus  tendon  belonging  to  the  index 
finger,  sometimes  also  from  the  accompanying 
tendon  of  the  flexor  sublimis  ;  the  second  lum- 
bricalis  arises  from  the  radial  side  of  the  tendon 
of  the  same  muscle  destined  to  the  middle 
finger ;  the  third  and  fourth  are  double  penni- 
form  arising  from  the  opposed  surfaces  of  the 
three  internal  tendons  of  the  same  muscle ; 
from  these  attachments  they  proceed,  the  two 
middle  vertically  downwards,  the  outer  out- 
wards, the  inner  inwards,  towards  the  outer 
side  of  the  metacarpophalangeal  articulations 
of  the  fingers,  where  they  end  in  flat  broad 
tendons,  which  are  inserted  into  the  outer 
border  of  the  common  extensor  tendon,  in 
common  with  the  tendons  of  the  correspond- 
ing interossei  with  which  they  are  confused  ; 


they  assist  in  completing  the  sheath  which  the 
extensor  tendons  form  for  the  back  of  the 
fingers. 

Relations. — Their  anterior  surface  is  covered 
by  the  tendons  of  the  flexor  sublimis,  by  the 
palmar  aponeurosis,  and  collateral  vessels  and 
nerves  of  the  fingers.  Their  posterior  surface 
lies  upon  the  interossei,  the  inferior  transverse 
metacarpal  ligament,  and  the  phalanges. 

Use. — They  assist  in  the  flexion  of  the  fingers 
upon  the  metacarpus,  at  the  same  time  drawing 
them  outwards,  they  steady  the  extensor  ten- 
dons, keeping  them  applied  to  the  phalanges. 

The  interossei,  of  which  there  are  seven  in  all, 
are  small  muscles  situated  between  the  meta- 
carpal bones,  to  which  ihey  are  attached  supe- 
riorly, their  inferior  attachment  being  to  the 
sides  of  the  first  phalanges  and  the  extensor 
communis  tendons;  there  are  three  on  the  pal- 
mar aspect,  which  are  simple,  and  four  on  the 
dorsal  aspect  of  the  hand,  which  are  bifid  mus- 
cles ;  there  are  two  to  each  interosseous  space, 
excepting  the  first,  which  has  only  one  :  we 
shall  first  examine  the  palmar  interossei. 

2.  Interossei  tnterni  digitorum  munus,  (rneta- 
carpo-phalangiais  lateralis  palmuires,  Chauss.) 
Short,  prismatic,  and  triangular;  they  arise,  the 
first,  or  posterior  indicts,  from  the  root  and  inner 
side  of  the  metacarpal  bone  of  the  fore-finger; 
the  second,  or  prior  annularis,  from  the  root  and 
outer  side  of  the  metacarpal  bone  of  the  ring 
finger ;  the  third,  or  interosseus  auricularis, 
from  the  root  and  outer  side  of  the  metacarpal 
bone  of  the  little  finger.  They  extend  along 
the  metacarpal  bones,  to  which  they  are  attach- 
ed, and  are  inserted  by  short  tendons;  the 
second  and  third  in  common  with  those  of  the 
lumbricales,  into  the  outer  and  upper,  and  the 
first  into  the  inner  and  upper  part  of  the  corre- 
sponding first  phalanges  and  side  of  the  exten- 
sor tendons. 

Relations. — Anteriorly  they  are  covered  by 
the  deep  flexor  tendons  and  palmar  muscles; 
posteriorly  they  correspond  to  the  dorsal  inter- 
ossei, which  are  also  connected  with  them 
alons  their  unattached  margin. 

Use. — The  simplest  way  of  regarding  their 
action,  which  is  rather  complex,  is  to  refer  it 
towards  the  axis  of  the  hand  or  a  central  line 
drawn  through  the  third  metacarpal  bone  and 
the  middle  finger,  in  which  case  it  is  easily 
perceived  that  the  palmar  interossei  are  adduc- 
tors towards  the  axis  of  the  hand. 

II.  The  only  intrinsic  muscles  on  the  dorsal 
aspect  of  the  hand  are  the  dorsal  interossei, 
interossei  esterni  digitorum  manus.  Their  com- 
mon points  are,  that  they  appear  both  on  the 
dorsal  and  palmar  aspects  of  the  hand  ;  they 
are  bicipital ;  arising  from  the  opposed  surfaces 
of  two  metacarpal  bones,  both  heads  termina- 
ting in  a  common  tendon,  which  is  attached  to 
the  sides  of  the  first  phalanges  and  extensor 
tendons  that  are  not  supplied  by  the  palmar  in- 
terossei. They  are  four  in  number;  the  first, 
or  adductor  indicis,  alone  merits  a  particular 
description.  It  is  the  largest;  arising  from  the 
superior  half  of  the  external  border  of  the  first 
metacarpal  bone,  and  externally  from  all  the 
external  surface  of  the  second  metacarpal  bone; 


522 


MUSCLES  OF  THE  HAND. 


these  origins  are  separated  by  a  fibrous  arch, 
through  which  the  radial  artery  passes  ;  they 
.ire  large  and  fleshy,  and  soon  unite,  forming  a 
triangular  flattened  muscle,  which  is  inserted 
into  the  external  side  of  the  first  phalanx.  The 
insertion  of  the  other  muscles  are,  the  two  mid- 
dle into  either  side  of  the  first  phalanx;  they 
are  called  the  prior  and  posterior  medii ;  and 
the  last,  or  posterior  annularis,  into  the  inter- 
nal side  of  the  ring-finger. 

Relations. — Posteriorly  they  correspond  to 
the  extensor  tendons  and  skin  ;  anteriorly  they 
appear  beside  the  palmar  interossei,  from  which 
they  are  separated  by  a  strong  septum  derived 
from  the  deep  palmar  aponeurosis.  Their  other 
relations  are  the  same  as  the  palmar  interossei. 
The  first,  the  abductor  indicis,  corresponds  an- 
teriorly to  the  adductor  pollicis  and  part  of  the 
flexor  brevis,  which  it  crosses  at  right  angles  ; 
its  inferior  and  external  margin  is  subcuta- 
neous. 

Use. — They  are  all  abductors  of  the  fingers 
from  the  axis  of  the  hand,  and  by  reason  of 
their  insertion  into  the  extensor  tendons,  act 
best  when  the  hand  is  extended.  The  same 
may  be  said  of  the  palmar. 

Before  we  enter  on  the  general  uses  of  this 
complex  muscular  apparatus,  it  would  be  well 
to  remark  that  the  proper  muscles  of  the  thumb 
and  little  finger  appear  to  be  nothing  more  than 
exaggerated  and  multiplied  lumbricales  and  in- 
terossei. We  may,  in  this  light,  view  the  short 
flexor  of  the  thumb  as  the  first  lumbricalis,  its 
abductor  and  opponens  as  a  dorsal  interosseus, 
while  its  adductor  would  represent  a  palmar 
interosseous  muscle;  again,  as  regards  the  little 
finger,  its  abductor  and  short  flexor  together 
personate  a  dorsal  interosseus,  while  its  adduc- 
tor would  be  but  an  internal  or  palmar  inter- 
osseous. Their  principal  use  is,  by  acting 
on  the  carpo-metacarpal  articulations  of  the 
thumb  and  little  finger,  which  enjoy  freer 
motion  than  the  intermediate  ones,  especially 
that  of  the  thumb,  to  oppose  these  extreme 
points  of  the  hand  to  each  other,  more  or  less 
increasing  its  concavity,  and  thereby  giving  a 
firmer  grasp,  inasmuch  as  they  adapt  the  cavity 
of  the  palm  to  the  volume  of  the  body  grasped. 
The  great  use  of  this  opposable  faculty  of  the 
thumb  (which  action  is  the  peculiar  characte- 
ristic of  the  hand  as  distinguishing  it  from  the 
foot)  may  be  shewn  by  firmly  clenching  the  fist, 
when  the  thumb,  by  its  combined  powers  of 
opposition  and  flexion,  is  made  to  overlap  the 
fore  and  middle,  and  in  some  the  third  fingers, 
pressing  them  firmly  against  the  palm,  while, 
at  the  same  time,  the  thenar  eminence  is 
thrown  forwards  and  inwards,  meeting  them  in 
the  palm,  and  by  abutting  against  counteracts 
their  tendency  to  fly  open  when  a  blow  is 
struck,  acting  at  the  same  time  as  a  cushion  to 
deaden  the  violence  of  the  shock.  We  here 
see,  also,  the  flexion  of  the  fingers  modified  by 
the  radial  interossei  and  lumbricales,  which, 
by  their  action,  throw  the  fingers  radiad,  so  as 
to  bring  the  three  outer  ones  to  abut  against 
the  thenar  eminence ;  the  little  finger  is  pro- 
tected, in  like  manner,  by  the  hypothenar, 
which  is  thrown  forwards  and  outwards.  The 


converse  modification  of  the  flexion  of  the 

fingers  by  means  of  the  ulnar  interossei  may 
be  seen  in  the  action  of  the  left  hand  of  a 
fiddler,  where  the  fingers  are  flexed  and  pointed 
ulnad  to  run  up  the  scale. 

It  only  remains  for  us  to  give  a  summary 
view  of  the  muscles,  extrinsic  and  intrinsic, 
concerned  in  the  motions  of  the  hand.  These 
motions  are  flexion,  extension,  adduction  or 
motion  ulnad,  abduction  or  motion  radiad. 
First,  the  flexors  of  the  wrist  are  six.  1. 
Flexor  longus  pollicis  ;  2  and  3,  flexor  sub- 
limis  et  profundus  ;  4,  palmaris  longus  ;  5, 
flexor  carpi  radialis;  6,  flexor  carpi  ulnaris. 
The  extensors  are  six.  1,  Extensor  communis; 
2,  indicator ;  3,  extensor  secundi  internodii 
pollicis ;  4  and  5,  extensores  carpi  radiales 
longior  et  brevior;  6,  extensor  carpi  ulnaris. 
The  last  three  of  the  extensors  as  well  as  the 
last  three  of  the  flexors  act  directly  on  the  wrist; 
the  others  act  first  on  the  phalanges.  These 
also  are  the  muscles  that,  in  extreme  flexion 
and  extension,  call  into  play  the  motion  that 
exists  between  the  two  rows  of  the  carpus,  the 
two  former  extending,  the  three  latter  flexing 
the  second  row  upon  the  first. 

The  adductors  are  five.  1,  Extensor  carpi 
ulnaris  ;  2,  extensor  communis  ;  3,  flexor  carpi 
ulnaris  ;  4,  sublimis  ;  5,  profundus. 

The  abductors  are  also  five.  1  and  2,  Ex- 
tensores ossis  metacarpi  et  primi  internodii 
pollicis ;  3  and  4,  extensores  carpi  radiales 
longior  et  brevior  ;  5,  flexor  carpi  radialis. 

The  following  table  is  intended  to  exhibit  at 
one  view  the  motions  of  which  the  lingers  are 
capable,  and  the  muscles  which  effect  them. 

The  movements  of  the  fingers  are — 

1.  Flexion  performed  by  nine. 
Flexor  longus  pollicis. 
Flexor  sublimis. 

Flexor  profundus. 

Three  internal  lumbricales. 

Three  interossei  interni. 

2 .  Extension  by  eight. 
Three  extensores  pollicis. 
Extensor  communis. 
Indicator. 

Three  internal  dorsal  interossei. 

3.  Adduction  by  seven. 

Three  adductor,  flexor  brevis,  and  oppo- 
nens pollicis. 

Abductor  minimi  digiti. 

Three  interossei,  viz.  posterior  indicis, 
posterior  medii,  posterior  annularis. 

4.  Abduction  by  eleven. 
Abductor  pollicis. 

Adductor  et  opponens  minimi  digiti. 
Four  lumbricales. 

Four  interossei,  viz.  abductor  indicis,  prior 
medii,  prior  annularis,  interosseus  au- 
ricularis. 

We  thus  see  that  the  hand  is  furnished  with 
no  less  than  thirty-three  muscles,  each  capable 
of  acting  either  singly  or  in  conjunction  with 
others.  The  most  powerful  of  these  are  the 
flexois  and  opposers,  both  performing  actions, 
as  we  have  seen,  peculiarly  adapted  for  the  pre- 
hension and  retention  of  bodies. 

But  there  is  yet  another  function  in  which 


REGIONS  OF  THE  HAND. 


523 


they  are  the  chief  agents,  and  of  which  the 
hand  is  the  principal  organ,  that  of  touch, 
which  may  be  regarded  as  a  kind  of  sentinel 
by  which  we  ascertain  the  nature  of  bodies  ; 
which  without  seeing  warns  the  hand  from  too 
closely  embracing  what  may  prove  hurtful  to 
itself,  or  admonishes  it  to  handle  gently  those 
delicate  objects  that  would  be  destroyed  by  too 
rude  a  grasp.  In  the  blind  this  sense,  by  con- 
slant  exercise,  becomes  so  perfect  as  in  a  great 
measure  to  compensate  for  the  loss  of  sight. 
But  by  the  combination  of  these  two  functions 
the  hand  is  indeed  rendered  an  organ  worthy 
of,  and  admirably  suited  to  the  mind  of  man. 
With  the  one  he  plans,  while  through  the  other 
he  performs  and  executes  all  that  administers 
to  the  pleasures,  the  comforts,  and  the  conve- 
niences of  life,  and  that  establishes  his  superi- 
ority in  the  creation. 

(F.  T.  M'DougaU.) 

HAND,  REGIONS  OF  THE.  (Surgical 
Anatomy.)  In  the  consideration  of  the  surgical 
anatomy  of  the  hand,  we  shall  commence  our 
description  from  an  imaginary  line  encircling 
the  fore-arm,  at  a  point  immediately  below  the 
insertion  of  the  pronator  quadratus,  or  about 
half  an  inch  above  the  radio-carpal  articulation. 
From  this  point  downwards  for  about  a  finger's- 
breadth,  the  wrist  is  narrow  and  flattened  like 
the  fore-arm ;  from  thence  the  hand,  gradually 
expanding,  acquires  that  remarkable  breadth 
and  flatness  so  necessary  to  it  both  as  a  tactile 
and  prehensile  organ  ;  it  is  broadest  inferiorly 
where  it  terminates  in  the  fingers.  In  front, 
this  region  is  concave  and  hairless ;  posteriorly, 
it  is  convex  and  slightly  hairy. 

In  woman,  the  hand  is  smaller  and  more  de- 
licately shaped  ;  it  is  also  rounder  and  smoother, 
on  account  of  the  greater  quantity  of  subcu- 
taneous adipose  tissue,  softening  down  the 
harsher  outline  of  bone  and  tendon  displayed 
in  the  brawny  hand  of  man. 

In  order  to  avoid  needless  prolixity,  we  shall 
not  subdivide  this  inferior  segment  of  the  upper 
extremity  into  the  three  distinct  regions  of  wrist, 
hand,  and  fingers  ;  which,  indeed,  if  we  were 
considering  its  bony  frame-work,  would  natu- 
rally present  themselves.  But  as  the  soft  parts, 
with  which  we  have  principally  to  do  in  the 
present  article,  exhibit  no  such  natural  distinc- 
tions in  these  separate  parts,  and  are,  for  the 
most  part,  common  to  them  all,  we  shall  con- 
sider them  as  constituting  one  entire  region, 
which  is  naturally  subdivided  into  palmar  and 
dorsal  regions. 

I.  Of  the  palmar  region  of  the.  hand. — The 
remarkable  points  on  the  exterior  of  this  region 
are  as  follows  : — Commencing  from  the  pre- 
supposed imaginary  line,  and  proceeding  down- 
wards, we  perceive  most  externally  a  projection 
formed  by  the  united  tendons  of  the  short  ex- 
tensors of  the  thumb  ;  next  in  order,  proceeding 
from  without  inwards,  we  notice  a  hollow,  most 
visible  when  the  hand  is  flexed,  corresponding 
to  the  radio-carpal  articulation,  and  in  which 
the  radial  artery  may  be  felt  pulsating  imme- 
diately before  it  passes  under  the  tendons  we 


have  just  noticed  ;  bounding  this  hollow,  on  its 
inside,  is  a  second  eminence,  formed  by  the 
tendons  of  the  flexor  carpi  radialis  and  palmaris 
longus,  and  the  projecting  crests  of  the  scaphoid 
and  trapezium  ;  more  internally  a  second  de- 
pression, corresponding  to  the  ulnar  nerve  and 
artery,  bounded  internally  by  a  third  eminence, 
that  of  the  flexor  carpi  ulnans  tendon  and  the 
pisiform  bone,  posterior  to  which  may  be  felt 
the  inferior  extremity  of  the  ulna  and  the  inter- 
val between  it  and  the  bones  of  the  carpus. 

Lastly,  in  front  of  the  wrist,  owing  to  the 
thinness  of  the  skin  in  this  part  of  the  palmar 
region,  we  perceive  a  blue  network  of  veins, 
from  which  the  median  is  formed. 

More  mferiorly,  in  the  palm  proper,  we  notice 
externally  the  thenar  eminence,  extending  from 
the  crest  of  the  scaphoid  to  the  base  of  the  first 
phalanx  of  the  thumb.  On  the  inner  side  of 
the  palm  is  the  hypothenar  eminence,  longer 
and  thinner,  but  less  prominent  than  the  last ; 
it  extends  from  the  pisiform  bone  to  the  base  of 
the  first  phalanx  of  the  little  finger.  Separating 
these  prominent  parts,  and  extending  from  the 
inner  furrow  of  the  wrist  towards  the  root  of 
the  index  finger,  is  a  deep  excavation, — the 
hollow  of  the  palm  ;  next  may  be  seen  or  felt 
four  elevations,  corresponding  to  the  heads  of 
the  four  metacarpal  bones,  about  an  inch  in 
front  of  which  the  fingers  free  themselves  from 
the  skin  of  the  palm,  which  is  prolonged  over 
them  for  that  distance  in  a  manner  somewhat 
analogous  to  the  web  in  the  foot  of  a  Newfound- 
land dog,  or  other  swimming  animals.  Of  the 
fingers  themselves,  the  middle  is  the  longest, 
the  first  and  third  are  on  a  level,  the  little  finger 
reaches  the  level  of  the  last  articulation  of  the 
annular,  and  the  thumb  terminates  about  three 
lines  behind  the  second  articulation  of  the  index; 
the  phalangeal  articulation  of  the  thumb  being 
exactly  on  a  level  with  the  metacarpo-phalangeal 
union  of  the  same  finger. 

There  are  likewise  certain  lines  or  furrows 
caused  by  the  folding  of  the  skin  in  flexion  of 
the  hand  and  fingers,  some  of  which  constantly 
occur,  and  are  worthy  of  notice,  inasmuch  as 
they  sometimes  serve  as  guides  or  landmarks  to 
the  surgeon  in  operating  on  this  region.  They 
are  as  follows:  two  on  the  wrist;  the  superior 
one,  extending  between  the  styloid  processes  of 
the  radius  and  ulna,  corresponds  to  the  radio- 
carpal articulation.  Another,  more  remarkable, 
slightly  convex  downwards,  projecting  between 
the  palmar  eminences,  separates  the  wrist 
from  the  hand,  and  corresponds  to  the  articula- 
tion between  the  two  rows  of  the  carpus.  In 
the  palm,  one  commences  from  the  metacarpo- 
phalangeal articulation  of  the  index  finger, 
which  soon  bifurcates,  one  of  its  divisions 
bounding  the  thenar  on  its  inner  side;  the  other 
runs  obliquely  across  the  palm,  and  terminates 
on  the  upper  part  of  the  hypothenar  :  this  in  a 
measure  corresponds  to  the  superficial  palmar 
arch,  having  the  same  obliquity  across  the  palm, 
but  being  three  or  four  lines  inferior  to  it ;  these 
lines  are  caused  by  the  opposition  of  the  thumb. 
There  is  yet  another  line  running  from  the  in- 
terval between  the  index  and  middle  fingers  to 


524 


REGIONS  OF  THE  HAND. 


the  base  of  the  little  finger;  this  traverses  the 
hand  about  two  lines  above  the  metacarpo- 
phalangeal articulations.  Opposite  the  joints 
of  the  fingers  there  are  also  transverse  lines ; 
the  two  first  have  double,  the  last  joint  but  a 
single  line  ; — an  incision  made  perpendicular 
to  it  would  fall  about  a  line  above  the  articula- 
tion. Of  the  middle  joint,  the  superior  trans- 
verse line  is  the  most  constant,  and  is  placed 
about  half  a  line  above  its  articulation. 

Of  the  lines  corresponding  to  the  first  joint 
of  the  fingers,  the  superior  is  on  a  level  with 
the  termination  of  the  interdigital  web,  and  from 
ten  lines  to  an  inch  below  the  articulation, 
excepting  that  of  the  thumb,  which  resembles 
the  middle  joint  of  the  fingers,  its  line  nearly 
corresponding  to  the  articulation.  There  are 
many  other  inconstant  folds,  or  markings  of  the 
skin,  in  this  region,  which,  to  the  surgeon,  are 
of  little  import,  but  which  present  a  book  of 
mystic  lore  to  the  gipsy  and  the  cheiromancer, 
wherein  (when  opened  by  the  necessary  charms) 
they  discern  the  future  destinies  of  all  that  seek 
to  be  enlightened  by  them. 

We  shall  now  proceed  to  examine  the  various 
structures  found  in  this  region,  and,  for  con- 
venience of  description,  shall  consider  them  as 
constituting  the  following  layers  : — 1,  skin  ; 
2,  subcutaneous  cellular  tissue,  vessels,  and 
nerves ;  3,  aponeurosis ;  4,  deep  vessels  and 
nerves  ;  5,  muscles  and  tendons. 

1.  The  skin. — The  integument  on  the  front 
of  the  wrist  resembles  that  on  the  anterior  sur- 
face of  the  fore-arm  ;  but,  on  reaching  the  palm, 
it  suddenly  changes  its  character,  and  instead  of 
the  fine,  smooth,  yielding  skin,  we  find  it  dense, 
resisting,  exceedingly  vascular,  and  covered 
with  a  very  strong  and  thick  cuticle  ;  on  the 
thenar,  however,  it  preserves  some  degree  of 
suppleness  and  elasticity.  In  those  accustomed 
to  hard  manual  labour,  and  in  the  aged,  the 
cuticle  becomes  so  thick  and  callous  as  to  en- 
able them  to  handle  even  hot  coals  without 
inconvenience  ;  but  in  them,  from  this  increased 
resistance,  and  from  the  difficulty  of  getting  at 
matter,  or  freeing  the  parts  by  incisions,  inflam- 
mations of  the  palm  are  the  more  dangerous. 
Corns  are  sometimes  developed  at  the  roots  of 
the  fingers,  on  the  prominences  formed  by  the 
heads  of  the  metacarpal  bones.  There  are  no  se- 
baceous follicles  to  be  discovered  in  this  region; 
but  M.  Velpeau  thinks,  from  the  fact  of  the 
occasional  appearance  of  variolous  pustules  on 
the  front  of  the  fingers,  that  follicles  there  exist. 
The  physical  conditions  of  the  skin  of  the 
hand,  as  to  coolness  or  warmth,  as  to  moisture 
or  dryness,  often  furnish  valuable  signs  in  dis- 
ease. 

2.  Subcutaneous  cellular  tissue  is  dense  and 
serrated,  more  fibrous  than  cellular,  enclosing 
in  its  meshes  small  rounded  pellets  of  fat.  On 
the  wrist  it  binds  the  skin  so  closely  to  the 
subjacent  parts,  that,  in  cases  of  serous  or  other 
infiltration  above  this  point,  the  effused  fluids 
are  arrested,  and  prevented  from  passing  into 
the  palm  of  the  hand ;  also,  in  very  fat  and 
flabby  people,  and  in  young  children,  a  kind  of 
strangulation  is  observable  at  the  wrist  from 


the  same  cause.  On  the  thenar  this  layer  is 
laxer  and  less  compact,  permitting  the  skin  to 
play  freely.  On  the  centre  of  the  palm  and 
hypothenar  it  is  very  dense  and  fibrous,  enclos- 
ing larger  pellets  of  fat,  binding  the  skin  very 
firmly  to  the  palrmr  aponeurosis  and  sheaths 
of  the  fingers,  towards  the  extremities  of  which 
it  becomes  more  fatty,  increases  in  thickness, 
forming  a  soft  elastic  cushion  called  the  pulp  of 
the  fingers.  This  tissue  is  the  seat  of  that  painful 
phlegmonous  inflammation,  the  true  whitlow. 
The  unyielding  natureof  the  thick  consistent  skin 
on  the  one  hand,  and  of  the  bones  and  sheaths 
on  the  other,  whereby  the  swollen  and  inflamed 
pulp,  together  with  its  great  number  of  vessels 
and  the  nervous  expansion  it  encloses,  are  vio- 
lently compressed,  easily  account  for  the  violent 
symptoms,  and  call  loudly  for  the  prompt  relief 
of  the  strangulation  by  means  of  the  knife,  and 
also  indicate  the  great  advantage  of  emollients. 

The  subcutaneous  nerves  are  few,  and  derived 
from  the  palmar  cutaneous  branch  of  the  median 
and  some  terminal  branches  of  the  internal  and 
musculo-cutaneous  nerves.  The  veins  are  also 
very  few,  and  give  rise  to  the  median,  and  are 
accompanied  by  the  superficial  lymphatics. 

3.  The  aponeurosis. — At  the  wrist  the  apo- 
neurosis, derived  from  that  of  the  front  of  the 
forearm,  is  interwoven  with  and  inseparable 
from  the  anterior  annular  ligament,  from  the 
lower  border  of  which,  and  from  the  tendon  of 
the  palmaris  longus,  the  palmar  fascia  proceeds. 
Above  the  annular  ligament  the  aponeurosis  is 
attached  to  the  extremity  of  the  ulna,  and  the 
pisiform  and  the  styloid  process  of  the  radius ; 
it  furnishes  sheaths  to  the  tendons  that  do  not 
pass  under  the  annular  ligament,  one  to  the  ul- 
nar and  its  nerve,  and  another  to  the  radial 
trunk  and  its  volar  branch.  The  anterior  annu- 
lar ligament  is  exceedingly  strong,  attached 
internally  to  the  pisiform  and  unciform,  and  ex- 
ternally to  the  scaphoid  and  trapezium.  It  con- 
sists of  two  layers,  the  one  superficial,  of  diver- 
gent fibres,  derived  from  the  tendon  of  the 
palmaris  longus  when  it  exists,  or  belonging  to 
the  origin  of  the  palmar  fascia  when  it  does 
not;  the  other  deep,  of  transverse  fibres,  con- 
tinuous with  the  fascia  of  the  forearm.  It 
forms,  together  with  the  concavity  of  the  pal- 
mar aspect  of  the  carpal  bones,  a  sort  of  ellipti- 
cal ring  about  two  inches  in  its  transverse,  and 
one  inch  in  its  antero-posterior  diameter,  and 
gives  passage  to  the  common  flexor  tendons  and 
median  nerve,  which  are  enveloped  by  a  com- 
mon synovial  bursa  which  binds  them  together, 
and  terminates  in  a  common  cul-de-sac  above 
and  below  the  ligament;  also  to  the  long  flexor 
tendon  of  the  thumb,  which  has  a  distinct 
bursa.  This  ligament,  from  its  great  strength, 
presents  an  insurmountable  obstacle  to  the  pro- 
gress of  tumours  developed  beneath  it,  forcing 
them  to  protrude  on  the  forearm  above  the  liga- 
ment in  the  hand  below  it.  Thus,  when  the 
common  synovial  bursa  of  the  tendons  is  dis- 
tended, it  forms  two  tumours,  the  one  above, 
the  other  below  the  ligament ;  and  upon  com- 
pressing the  fluid  from  one  the  other  will  be 
found  to  enlarge.    Ganglia  rarely  occur  here. 


REGIONS  OF  THE  HAND. 


525 


The  annular  ligament  gives  attachment  inferiorly 
on  either  side  to  the  muscles  of  the  thumb  and 
little  ringer,  and  in  the  centre  to  the  palmar 
fascia,  a  dense  fibrous  layer  binding  down  the 
flexor  tendons  in  their  passage  along  the  hand. 

The  pulmar  fascia  is  chiefly  derived  from 
the  expansion  of  the  palmaris  longus,  which, 
when  present,  is  its  tightening  muscle.  It 
is  strongest  in  the  palmar  hollow,  where  it 
is  triangular  in  shape,  its  apex  at  the  an- 
nular ligament,  and  is  composed  of  divergent 
and  longitudinal,  interwoven  with  a  few  trans- 
verse fibres;  the  latter,  becoming  gradually 
fewer  and  more  scattered,  are  lost  on  the 
tendons  running  to  the  fingers,  and  some  few 
are  at  times  continuous  with  the  tendinous 
sheaths  of  the  fingers.  Near  the  roots  of  the 
fingers  this  portion  of  the  palmar  fascia  divides 
into  four  hands,  which  subdivide  each  into  two 
tongue-like  processes,  that  embrace  the  heads 
of  the  metacarpal  bones,  and  are  attached  to 
the  sides  of  the  first  phalanges  and  the  inferior 
transverse  metacarpal  ligament.  At  this  point 
of  division  the  transverse  fibres  are  stengthened, 
and  convert  these  slits  into  four  distinct  fibrous 
arches,  through  which  pass  the  flexor  tendons. 
Between  these  arches  we  find  three  lesser  ones 
resulting  from  the  primary  division  of  the  fascia. 
They  transmit  the  collateral  vessels  and  nerves, 
and  the  lumbricales.  This  fascia  is  intimately 
connected  with  the  preceding  layer  anteriorly, 
its  deep  surface  covering  the  superficial  palmar 
arch,  flexor  tendons,  ulnar  and  median  nerves, 
from  which  it  is  separated  by  loose  and  very 
extensible  cellular  tissue,  which  permits  the 
tendons  to  play  freely.  This  portion  of  the 
fascia  presents  numerous  apertures  through 
which  the  deep  fat  and  cellular  tissue  commu- 
nicate with  the  subcutaneous,  and  when  the 
parts  beneath  are  swollen  they  protrude,  form- 
ing small  hernia3,  which,  getting  strangulated  in 
these  apertures,  give  rise  10  great  pain.  It  de- 
taches from  either  side  two  processes,  a  superfi- 
cial and  a  deep  one.  The  two  deep  processes 
dive  deep  into  the  palm,  to  form  the  interosseous 
aponeurosis  ;  of  the  superficial  ones,  the  exter- 
nal, assisted  by  the  tendinous  expansion  of  the 
extensor  ossis  metacarpi,  envelopes  the  thenar 
muscles;  the  interna)  stronger,  and  assisted  by 
the  flexor  carpi  ulnaris  expansion,  encloses 
the  hypothenar  muscles,  and  to  it  is  attached 
the  palmans  brevis.  We  next  meet  with  the 
strong  sheaths  binding  down  the  flexor  tendons 
in  their  passage  along  the  fingers.  They  are 
continuous  above  with  the  palmar  fascia,  by 
means  of  strong  detached  transverse  fibres, 
which  are  prolonged  over  the  tendons  ,as  they 
pass  through  the  arches  of  the  fascia;  laterally 
they  are  firmly  attached  to  the  ridges  on  the 
sides  of  the  phalanges.  On  the  bodies  of  the 
two  first  phalanges  these  sheaths  are  very 
strong  and  resisting;  but  opposite  the  articula- 
tions they  become  very  thin,  and  are  often 
wanting;  so  that  the  synovial  sacs  of  the  ten- 
dons are  in  contact  with  the  subcutaneous  layer; 
and  it  is  through  these  spaces  that  the  inflam- 
mation in  whitlow  is  propagated  to  the  synovial 
membrane  and  joints.  At  the  last  joint  of  the 
fingers  they  become  weak  and  thin,  and  are 


confounded  with  the  pulp  and  periosteum. 
They  each  enclose  a  distinct  elongated  synovial 
sac,  which  reaches  as  far  upwards  as  the  fibrous 
arch  of  the  fascia,  but  does  not  communicate 
with  the  synovial  membranes  of  the  joints,  en- 
tirely enveloping  the  flexor  tendons,  lubricating 
them,  and  facilitating  these  motions  in  the 
sheaths.  At  the  point  where  the  tendon  of  the 
profundus  passes  through  the  divisions  of  the 
sublimis,  there  is  a  falciform  process  of  the 
synovial  sheath  of  considerable  strength,  at- 
taching the  tendon  of  the  latter  to  the  first  pha- 
lanx, so  that  if  the  fingers  be  amputated  at  the 
second  joint,  the  power  of  moving  the  first 
phalanx  will  still  be  retained,  though  the  con- 
trary has  been  stated.  We  may  here  likewise 
notice  that  the  gradual  contraction  of  the  three 
last  fingers  occurring  in  adults,  (crispatura  ten- 
dinum,)  formerly  thought  incurable,  as  it  was 
supposed  to  be  the  result  of  a  drying  or  con- 
traction of  the  tendons,  is  stated  by  Baron 
Dupuytren  to  be  nothing  more  than  a  band  or 
strip  of  the  palmar  fascia,  adhering  to  the 
sheath  of  the  tendon,  upon  the  division  of 
which  a  complete  cure  may  be  effected;  or  it 
may  be  caused  by  a  fibrous  transformation  of 
the  subcutaneous  cellular  layer,  depriving  it  of 
its  elasticity,  and  causing  it  to  contract,  so  that 
the  finger  cannot  be  extended.  What  favours 
this  opinion  is,  that  this  malady  generally  oc- 
curs in  labourers,  boatmen,  and  those  whose 
avocations  necessitate  constant  flexion  of  the 
fingers,  at  the  same  time  that  firm  pressure  is 
kept  up,  especially  against  the  roots  of  the 
three  inner  fingers,  as  in  handling  a  spade,  or 
grasping  an  oar. 

4.  The  vessels  and  nerves  are  exposed  on 
removing  the  fascia,  being  immediately  under- 
neath it.  The  palmar  aspect  of  the  hand  being 
that  of  flexion,  according  to  the  general  rule  of 
arterial  distribution,  the  principal  trunks  are 
there  found;  they  are  the  ulnar  and  radial 
arteries,  and  a  branch  of  the  interosseous  ac- 
companying the  median  nerve. 

The  ulnar  artery  at  the  wrist  lies  on  the 
annular  ligament,  to  the  radial  side  of  the  pisi- 
form bone,  where  it  is  covered  by  the  expan- 
sions of  the  flexor  carpi  ulnaris;  it  then  curves 
towards  the  mesial  line,  and  crossing  the  annu- 
lar ligament,  traverses  the  palm  between  the 
fascia  and  the  flexor  tendons,  in  a  curved  direc- 
tion towards  the  centre  of  the  metacarpal  bone 
of  the  index  finger.  In  this  course  it  forms  an 
arch,  the  convexity  of  which  looks  downwards 
and  inwards,  towards  the  ring  and  little  fingers, 
its  concavity  being  turned  to  the  ball  of  the 
thumb.  It  then  inosculates  with  two  branches 
from  the  radial,  the  superficialis  vola;,  and  the 
radialis  indicis,  forming  thus  the  superficial 
palmar  arch,  from  the  convexity  of  which  pro- 
ceed four  digital  arteries  which  subdivide  into 
the  collateral  branches  at  about  two  lines  below 
the  metacarpo-phalangean  articulations ;  they 
supply  the  palmar  and  lateral  surfaces  of  all  the 
fingers  except  the  thumb  and  the  radial  side  of 
the  index  finger.  They  all  run  along  the  sides 
of  the  fingers  external  to  the  sheaths,  to  the 
last  phalanx,  where  those  of  either  side  coalesce, 
forming  an  arch,  from  which  arise  numerous 


526 


REGIONS  OF  THE  HAND. 


brandies  to  supply  the  pulp  of  the  fingers. 
When  the  artery  arrives  at  the  wrist,  it  sends 
off  two  regular  branches,  the  arteriae  carpi  ulna- 
res  anterior  et  posterior,  to  the  fore  and  back 
parts  of  the  joint.  After  crossing  the  annular 
ligament,  it  detaches  also  a  deep  communicat- 
ing branch,  which  dips  down  between  the 
flexor  brevisand  abductor  minimi  digiti,  to  join 
the  deep  arch  from  the  radial. 

The  radial  artery,  just  below  the  styloid 
process  of  the  radius,  passes  round  to  the  back 
of  the  wrist  under  the  two  external  extensors  of 
the  thumb,  to  the  cleft  between  the  two  first 
metacarpal  bones,  where  it  again  passes  into 
the  palm  between  the  heads  of  the  first  dorsal 
interosseous,  and  then  between  the  short  flexor 
and  adductor  of'the  thumb,  to  form  with  the 
communicating  branch  from  the  ulnar  the  deep 
palmar  arch.  In  this  course  it  lies  upon  the 
capsular  and  external  lateral  ligaments,  and 
close  upon  the  head  of  the  first  metacarpal 
bone;  it  is  therefore  generally  divided  in  the 
amputation  of  that  bone  ;  but  it  would  often  be 
avoided,  were  the  edge  of  the  knife  kept  close 
to  the  inner  side  of  the  bone,  as  it  is  carried 
down  to  the  joint.  Before  it  curves  round  the 
wrist,  this  artery  gives  off  the  superficialis  voire, 
a  branch  which  runs  over  the  annular  ligament 
to  unite  with  the  superficial  palmar  arch;  also  the 
anterior  carpal  branch,  which  anastomoses  with 
the  anterior  interosseous  and  corresponding  ulnar 
branch.  At  the  back  of  the  carpus  it  detaches 
the  dorsalis  carpi  radialis,  which  inosculates 
with  the  corresponding  branch  from  the  ulnar; 
it  runs  beneath  the  extensor  tendons,  supplying 
the  synovial  membrane  and  the  bones  of  the 
carpus  ;  it  also  anastomoses  with  the  posterior 
interosseous.  This  branch  generally  sends  off 
the  metacarpal  artery,  which  forms  a  kind  of 
posterior  arch  across  the  heads  of  the  metacarpal 
bones,  that  supplies  the  integuments  and  mter- 
ossei  muscles  ; — this  metacarpal  branch  some- 
times arises  from  the  trunk  of  the  radial.  The 
only  remaining  dorsal  branches  are,  the  arteria; 
dorsales  pollicis,  in  general  two  distinct  branches, 
but  sometimes  arising  by  a  common  trunk. 
They  run  along  the  dorsum  of  the  thumb,  the 
one  on  the  radial,  the  other  on  its  ulnar  side  ; 
this  last  sends  a  branch  to  the  index  finger,  the 
dorsalis  indicis.  The  radial  artery  then  dips 
deep  into  the  palm,  as  before  described,  and 
divides  into  its  three  terminal  branches:  the 
first  is  the  magna  pollicis,  which  runs  along  the 
ulnar  side  of  the  metacarpal  bone  of  the  thumb, 
and  at  its  inferior  extremity  divides  into  two 
collateral  branches,  which  are  distributed  simi- 
larly to  those  of  the  fingers.  The  next  branch 
is  the  radialis  indicis,  which  forms  the  external 
collateral  artery  of  that  finger;  it  receives  a 
branch  of  communication  from  the  superficial 
palmar  arch.  Lastly,  the  arteria  palmaris  pro- 
funda ;  this  runs  deeply  into  the  palm,  generally 
separating  the  flexor  brevis  and  adductor  pollicis 
muscles.  It  crosses  the  interossei  and  anterior 
part  of  the  superior  extremities  of  the  metacarpal 
bones  ;  it  is  covered  by  the  deep  flexor  tendons 
and  lumbricales ;  and  opposite  the  fifth  meta- 
carpal bone  inosculates  with  the  communicating 
ulnar, — completing  thus  the  deep  palmar  arch, 


the  convexity  of  which  is  towards  the  fingers  ; 
and  it  gives  four  or  five  regular  branches,  which 
supply  the  interossei,  and  at  the  clefts  of  the 
fingers  anastomose  with  the  digital  branches. 
This  arch  is  less  oblique,  and  farther  from  the 
finders,  than  the  superficial  one. 

Thus  we  see  that  the  disposition  of  the  arteries 
of  the  hand  is  peculiar,  and  is  somewhat  analo- 
gous to  that  of  the  venous  system  generally, — ■ 
viz.  that  they  are  divided  into  a  superficial  and 
deep  set.  The  question  naturally  occurs,  whe- 
ther it  may  not  be  for  the  same  cause,  viz.  that 
when  pressure  obstructs  the  superficial  vessels, 
the  deep  may  still  carry  on  the  interrupted  cir- 
culation? In  the  hand,  as  we  have  seen,  the 
communications  between  the  deep  and  super- 
ficial arches  are  frequent  and  free,  while  we 
daily  experience  with  what  violent  and  continued 
pressure  the  circulation  through  the  superficial 
arch  is  liable  to  be  interrupted. 

The  varieties  of  the  arteries  of  the  hand  are 
numerous  :  sometimes  the  radial  predominates, 
at  other  times  the  ulnar,  in  the  share  they  respec- 
tively take  in  supplying  the  hand ;  they  are 
always  in  an  inverse  ratio;  and  if  both  are  small, 
then  the  artery  of  the  m.  dian  nerve  derived 
from  the  interosseous  is  proportionably  large. 

From  the  constant  call  for  vigorous  and  rapid, 
as  well  as  sustained  and  powerful  action,  the 
hand,  with  the  exception  of  the  tongue,  is  the 
most  vascular  of  the  voluntary  locomotive  mem- 
bers of  the  human  body.  The  communications 
between  its  arteries  are  so  numerous  and  free,  as, 
in  cases  of  simple  wounds  of  this  region,  fre- 
quently to  prove  a  source  of  great  embarrass- 
ment to  the  surgeon,  and,  in  unskilful  hands,  of 
danger  to  the  patient.  Wounds  of  the  integu- 
ments of  the  palm  often  bleed  profusely,  and 
are  liable  to  secondary  haemorrhage.  This  may 
in  some  measure  be  accounted  for  by  the  pecu- 
liar density  of  the  cellular  tissue  and  skin,  and 
its  intimate  connection  with  the  subjacent  fascia, 
which,  as  well  as  the  numerous  branches  given 
off  from  the  divided  vessels,  prevent  their  re- 
traction, nor  can  a  coagulum  easily  form  around 
them  ;  they  are  not  generally  vessels  that  require 
a  ligature,  (excepting  in  cases  similar  to  one 
related  by  M.  Velpeau,  where  the  arteries  of 
the  hand  were  in  a  varicose  state,  and  of  an 
enormous  size,)  but  where  ordinary  means  fail, 
plugging  the  wound,  the  continued  application 
of  cold,  and  a  tightish  bandage  up  to  the 
shoulder,  in  order  to  moderate  the  circulation 
in  the  whole  limb,  will  usually  stop  even  very 
severe  bleedings.  If  these  means  should  not 
succeed,  and  no  large  divided  vessels  can  be 
seen  in  the  wound,  the  surgeon  must  tie  one  or 
even  both  arteries  above  the  wrist.  The  inos- 
culations with  the  interosseous  will  sometimes 
even  then  allow  the  bleeding  to  continue,  espe- 
cially in  cases  where  the  median  branch  is 
large,  or  helps  to  form  the  arch ;  but  pressure 
and  cold  will  then  soon  stop  the  remaining 
haemorrhage. 

Veins. — The  deep  ones  accompany  their 
arteries ;  the  superficial  veins  are  very  few  on 
the  palm. 

The  lymphatics  accompany  the  veins. 

The  nerves  of  this  region  are  superficial  and 


REGIONS  OF  THE  HAND. 


527 


deep :  the  former  have  been  already  noticed ; 
the  latter  are  the  median  and  ulnar.  The  first 
passes  under  the  annular  ligament  with  the 
flexor  tendons ;  it  then  divides  into  five  branches, 
behind  the  superficial  palmar  arch.  The  first, 
or  most  external  of  these  branches,  supplies 
the  short  muscles  of  the  thumb  ;  the  second 
sends  one  or  two  deep  branches  down  to  the 
interossei,  to  communicate  with  the  deep  palmar 
branch  of  the  ulnar  nerve  ;  it  then  finishes  on 
the  outer  side  of  the  thumb;  the  remaining 
three  branches  soon  bifurcate,  and  are  distri- 
buted to  the  ulnar  side  of  the  thumb,  to  both 
sides  of  the  index  and  middle,  also  to  the  radial 
side  of  the  ring  finger ;  giving  likewise  a  branch 
to  each  corresponding  lumbrical  muscle. 

The  ulnar  nerve  passes  over  the  annular  liga- 
ment to  the  internal  and  posterior  side  of  its 
artery  ;  while  passing  over  the  ligament,  it  sends 
the  cutaneous  branch  to  the  skin  on  the  hypo- 
thenar,  and  then  it  divides  into  three  branches  : 
first,  the  deep  palmar  branch,  which  accom- 
panies the  communicating  branch  of  the  artery, 
and  behind  the  deep  palmar  arch  unites  with 
the  branch  sent  from  the  median  to  supply  the 
deep  muscles ;  the  next  branch  supplies  the 
ulnar  side  of  the  little  finger  and  its  muscles  ; 
while  the  remaining  branches  supply  the  col- 
lateral nerves  not  furnished  by  the  median,  to 
the  radial  side  of  the  little,  and  the  ulnar  side 
of  the  ring  fingers.  All  these  collateral  nerves 
accompany  the  corresponding  arteries  along  the 
sides  of  the  fingers,  giving  numerous  branches 
in  their  course  that  terminate  in  the  skin  ;  and 
on  the  last  phalanx  they  divide  into  two  brandies, 
a  dorsal  and  palmar  :  the  dorsal,  or  ungual 
branch,  is  lost  in  the  skin,  under  the  nail ;  and 
the  palmar  is  expanded  in  the  pulp  of  the 
fingers.  It  is  remarkable  that  the  nerves  of  the 
opposite  sides  of  the  fingers  never  anastomose. 

The  muscles  and  tendons  with  which  the 
hand  is  pre-eminently  endowed,  lastly  present 
themselves  for  our  consideration.  In  the  upper 
part  of  this  region,  or  in  front  of  the  wrist, 
there  are  scarcely  any  muscular  fibres,  except- 
ing a  small  portion  of  the  origins  of  the  thenar 
and  hypothenar  muscles ;  and  sometimes  the 
lower  border  of  the  pronator  quadratus  reaches 
as  far,  or  a  little  below  the  imaginary  line  we 
have  marked  out  as  the  superior  boundary  of 
this  region.  But  we  have  no  lack  of  tendons 
in  this  part;  for  we  here  find  an  assemblage  of 
them  more  numerous,  and  more  tightly  packed, 
than  in  any  other  part  of  the  body  ;  they  are 
also  invested  by  synovial  sacs,  and  pass  through 
the  carpal  ring,  which  was  described  in  speak- 
ing of  the  annular  ligament  in  which  they  are 
closely  bound  down.  There  are,  however,  some 
that  do  not  pass  through  this  ring,  and  they  are 
the  following  : — Most  externally  is  the  tendon 
of  the  supinator  longus,  which  terminates  by 
being  inserted  into  the  radius  at  the  upper 
boundary  of  this  region ;  then  the  tendons  of 
the  extensores  ossis  metacarpi,  and  primi  inter- 
nodii  pollicis,  running  in  the  most  external 
groove  in  the  radius,  which  is  converted  into  a 
sheath  for  them  by  a  process  of  the  posterior 
annular  ligament.     The  radial  artery  passes 


under  these,  separating  them  from  the  joint  in 
its  passage  to  the  back  of  the  wrist. 

More  internally  we  have  the  tendon  of  the 
flexor  carpi  radialis  passing  into  the  palm,  be- 
hind the  external  reflected  portion  of  the  annu- 
lar ligament,  in  a  canal  destined  for  it  in  the 
scaphoid  and  trapezium  ;  the  next  tendon  is 
that  of  the  palmaris  longus,  which  here  begins 
to  expand  on  the  anterior  surface  of  the  annular 
ligament,  to  -which  it  is  also  attached;  and 
lastly,  we  find  the  flexor  carpi  ulnaris  tendon 
implanting  itself  into  the  pisiform  bone.  This 
tendon,  and  those  of  the  short  extensors  of  the 
thumb,  form  the  lateral  boundaries  of  this 
region,  dividing  it  from  the  dorsal. 

All  the  other  tendons  from  the  front  of  the 
fore-arm  pass  through  the  carpal  ring ;  they 
are  nine  in  number  : — Four  of  the  flexor  subli- 
nes ;  four  of  the  flexor  profundus, — these  are 
all  bound  up  in  a  common  synovial  sheath, 
along  with  the  median  nerve;  the  remaining 
tendon,  that  of  the  flexor  pollicis,  is  situated 
more  externally,  and  has  a  distinct  synovial  sac. 
All  these  tendons,  after  emerging  from  under 
the  annular  ligament,  diverge  towards  the  differ- 
ent fingers  to  which  they  are  destined.  In  the 
palm  they  are  placed  beneath  the  aponeurosis, 
and  lie  upon  the  palmar  interossei  and  the 
adductor  pollicis. 

As  the  muscles  of  the  palm  have  already 
been  described,  (see  Hand,  muscles  of,)  we 
shall  not  notice  them  further  than  merely  to 
observe,  that  the  intrinsic  muscles  of  the  thumb 
and  little  finger  constitute  the  external  and  in- 
ternal regions  of  the  palm,  which  they  almost 
solely  occupy ;  while  the  middle  region,  or 
hollow  of  the  palm,  is  occupied  not  only  by 
the  remaining  intrinsic  muscles,  (the  interossei 
and  lumbricales,)  but  also  contains  the  tendons 
just  described,  with  their  synovial  sheaths,  as 
well  as  the  principal  vascular  and  nervous 
trunks  of  the  hand.  Wounds  are  therefore  more 
dangerous  in  the  middle  of  the  palm  than  on 
either  the  external  or  internal  regions,  which 
are  constituted  principally  of  muscle,  having 
but  a  thin  aponeurosis  and  no  important  vessels 
or  nerves.  It  is  also  worthy  of  remark,  that 
the  short  muscles  of  the  thumb,  especially  the 
abductor,  flexor  brevis,  and  adductor,  though 
they  act  but  indirectly  on  the  first  metacarpal 
bone,  present  a  serious  obstacle  to  its  dislocation 
forwards  ;  their  action  tending  to  throw  its  base 
backwards,  whilst,  by  their  bulk  and  tension, 
they  repel  its  attempts  to  slip  forwards. 

Having  now  examined  all  the  soft  parts  on 
the  palmar  region,  as  nearly  as  possible  in  the 
order  in  which  they  would  have  been  exposed 
by  the  dissector,  we  proceed  to  the  second 
division  of  our  subject,  and  shall  consider  the 
various  layers  of  the  dorsal  region  in  similar 
order. 

II.  The  dorsal  region  of  the  hand  is  convex 
and  irregular;  the  veins  are  large  and  promi- 
nent. When  the  hand  is  extended  the  extensor 
tendons  stand  out  in  strong  relief,  converging 
at  the  wrist ;  and  when  flexed  the  heads  of  the 
metacarpal  bones  and  phalanges  protrude.  The 
other  prominent  external   characters  of  this 


528 


REGIONS  OF  THE  HAND. 


region  are,  at  the  superior  and  external  part, 
when  the  thumb  is  extended  and  abducted, 
an  elongated  depression,  bounded  externally 
by  the  two  short  extensor  tendons  of  the  thumb, 
and  internally  by  its  long  extensor  and  the 
tendon  of  the  extensor  carpi  radialis  longior. 
In  this  depression  the  pulsation  of  the  radial 
artery  may  be  felt,  also  the  heads  of  the  two 
first  metacarpal  bones:  internally  and  about 
the  same  level  there  is  a  hollow  corres- 
ponding to  the  union  of  the  wrist  and  hand  ; 
and  at  this  point  we  can  feel  the  tendon 
of  the  extensor  carpi  ulnaris  and  the  sty- 
loid process  of  the  ulna.  When  the  thumb  is 
adducted  the  first  dorsal  interosseous  projects 
considerably.  The  fingers  appear  longer  on 
their  dorsal  aspect,  the  interdigital  web  that 
was  noticed  on  their  palmar  surface  being  here 
wanting. 

1.  The  skin  is  very  loose  and  thrown  into 
transverse  folds;  opposite  the  two  last  joints  of 
the  fingers  may  generally  be  seen  three  or  more 
transverse  furrows;  the  middle  one  is  the 
deepest  and  most  constant,  and  an  incision 
made  about  a  line  and  a  half  below  it  will  hit 
upon  the  articulation.  It  resembles  that  on 
the  back  of  the  fore-arm,  but  it  gradually 
thickens  at  the  sides  as  it  approaches  the  palmar 
surface.  Hairs  and  sebaceous  follicles  are 
most  abundant  on  the  ulnar  side  of  the  back  of 
the  hand  and  on  the  first  phalanges.  On  the  un- 
gual phalanx,  the  skin,  as  it  approaches  the  nail, 
becomes  tighter  and  glabrous,  extends  for  about 
two  lines  over  the  root  of  the  nail,  and  is  then 
reflected  back,  so  as  to  be  continued  over  its 
anterior  surface  to  its  free  border,  where  it 
becomes  continuous  with  the  skin  of  the  pulp 
of  the  fingers.  It  is  in  this  portion  of  the  skin 
about  the  roots  of  the  nails  that  the  false  whit- 
low, called  by  the  French  tourniole,  takes 
place.  It  is  an  inflammation  more  of  an 
erysipelatous  than  a  phlegmonous  nature,  some- 
times attacking  several  fingers  successively  or 
at  once,  therein  differing  from  the  true  whitlow, 
which  is  generally  confined  to  one  finger. 
Warts  also  frequently  occupy  the  skin  of  the 
dorsum  of  the  fingers,  especially  in  those  that 
have  to  perform  hard  manual  labour. 

2.  The  subcutaneous  layer  is  very  lax,  serous 
infiltration  easily  taking  place;  it  contains  no 
pellets  of  fat  like  that  of  the  palmar  surface. 

The  veins  are  subcutaneous,  large  and  nu- 
merous; all  the  large  veins  of  the  hand  being 
on  its  dorsal  surface,  the  venous  circulation  is 
not  interrupted  by  the  effort  of  prehension. 
On  the  back  of  the  fingers  they  form  a  com- 
plete net-work,  which  gives  rise  to  the  dorsal 
collateral  veins  of  the  fingers.  At  the  inter- 
osseous spaces  these  unite  as  the  arteries  di- 
vide, and  then  proceed  towards  a  kind  of  dorsal 
venous  arch,  the  concavity  of  which  is  upwards, 
and  from  which  arise  larger  branches;  these, 
in  conjunction  with  one  from  the  little  finger 
called  the  vena  salvatella,  and  another  from  the 
thumb  called  the  cephalic,  form  the  basilic  and 
cephalic  veins  described  in  the  fore-arm.  (See 
Fore-arm.)  Some  people  prefer  being  bled 
on  the  back  of  the  hand,  but,  owing  to  the 


laxity  of  the  skin  and  subcutaneous  layer,  con- 
siderable extravasation  of  blood  is  apt  to  take 
place.  The  subcutaneous  nerves,  derived  from 
the  dorsal  branch  of  the  ulnar,  and  the  ter- 
minal branches  of  the  musculo-spiral  accom- 
pany the  veins,  as  also  do  the  lymphatics. 

3.  The  aponeurosis  is  continued  from  that  of 
the  back  of  the  fore-arm ;  it  is  strengthened 
across  the  back  of  the  wrist  by  strong  parallel 
oblique  fibres,  forming  a  band  of  nearly  an 
inch  in  breadth;  which  extends  obliquely  down- 
wards over  the  extensor  tendons  from  the  sty- 
loid process  of  the  radius  to  the  internal  lateral 
ligament  of  the  wrist*  It  sends  down  strong 
processes  between  the  tendons  that  convert  the 
grooves  in  the  back  of  the  radius  and  ulna  into 
sheaths,  which  are  as  follows: — 1st,  that  noticed 
on  the  palmar  region  for  the  short  extensors  of 
the  thumb  ;  2d,  for  the  radial  extensors;  3d,  for 
the  long  extensor  of  the  thumb ;  4th,  for  the 
extensor  communis  and  indicator  tendons; 
5th,  for  the  extensor  minimi  digiti ;  6th  and 
last,  for  the  extensor  carpi  ulnaris.  The  meta- 
carpal aponeurosis  is  very  thin  and  split  into 
two  layers ;  the  one  separates  the  subcutaneous 
layer,  vessels,  and  neives  from  the  tendons; 
the  other  covers  the  dorsal  interossei,  isolating 
them  from  the  tendons. 

4.  The  nerves  are,  externally,  the  jadial, 
which  sends  one  branch,  that,  bifurcating,  sup- 
plies the  thumb  and  radial  side  of  the  index 
finger ;  and  another,  which  in  like  manner  fur- 
nishes the  inside  of  the  index  and  the  middle 
finger.  Internally  the  posterior  branch  of  the 
ulnar  supplies  the  two  remaining  fingers.  These 
branches  receive  frequent  communicating  ramuli 
from  the  anterior  collateral  nerves. 

5.  Tendons  and  muscles. — The  former  are 
less  numerous  on  this  region  than  on  the  pal- 
mar; the  order  in  which  they  cross  the  wrist 
was  mentioned  in  describing  the  aponeurosis. 
If  the  divisions  of  the  extensor  communis  be 
enumerated,  they  are  twelve  in  number ;  four 
of  these  are  inserted  at  the  base  of  the  meta- 
carpal bones  of  the  thumb,  index,  middle,  and 
little  fingers ;  they  are  the  extensor  ossis  meta- 
carpi  pollicis,  extensores  carpi  radiales,  and 
extensor  carpi  ulnaris.  The  other  tendons 
proceed  onwards  to  the  phalanges.  Those  of 
the  common  extensor  are  flattened  and  riband- 
like; the  three  inner  ones  communicate  with 
each  other,  while  that  going  to  the  index  is 
free.  Opposite  the  metacarpo-phalangean  arti- 
culation these  tendons  narrow  and  thicken, 
sending  an  expansion  to  either  side  of  the 
articulation :  they  again  flatten  on  the  first 
phalanges,  where  they  receive  the  tendons  of 
the  lumbricales  and  interossei.  At  the  articu- 
lation of  the  first  and  second  phalanges  they 
divide  into  three  portions:  a  middle  one,  that 
is  inserted  into  the  superior  extremity  of  the 
second  phalanx;  and  two  lateral  ones,  that  run 
along  its  sides,  reunite  at  its  inferior  end,  and 
are  implanted  into  the  upper  part  of  the  ungual 


*  Generally  called  the  posterior  annular  liga- 
ment. 


ORGAN  OF  HEARING. 


529 


phalanx.*  The  remaining  tendons  of  the  index 
and  little  fingers  are  implanted  into  the  pha- 
langes of  those  fingers  with  those  of  the 
common  extensor :  those  nf  the  thumb  are 
inserted  separately.  Having  no  sheaths,  these 
tendons  are  firmly  attached  by  means  of  a 
membranous  expansion  to  the  bones  to  prevent 
them  slipping  aside,  nor  have  they  here  any 
synovial  membranes,  and  are  therefore  in  con- 
tact with  those  of  the  joints;  but  as  they  pass 
through  the  sheaths  in  the  posterior  annular 
ligament,  they  are  all  provided  with  synovial 
sacs.  The  largest  is  that  of  the  extensor  com- 
munis and  indicator;  they  are  less  complex 
than  those  of  the  palmar  region,  and  their 
inflammation  less  formidable  and  not  so  pain- 
ful. The  occurrence  of  ganglia  is  here  very 
frequent.  They  sometimes  attain  a  large  size 
and  produce  considerable  inconvenience.  The 
puncture  of  them  is  not  so  dangerous  here  as 
in  the  palmar  region. 

6.  Arteries— The  course  of  the  radial  over 
the  back  of  the  hand  has  been  already  noticed  ; 
its  metacarpal  and  carpal  branches  run  across 
the  wrist  beneath  the  extensor  tendons,  unite 
with  the  posterior  carpal  branch  of  the  ulnar, 
forming  a  kind  of  dorsal  arch,  from  which  pro- 
ceed the  interosseous  and  perforating  branches, 
Ho  communicate  with  the  deep  arch ;  also  the 
dorso-digital  branches,  one  to  either  side  of  the 
fingers. 

The  bones  and  ligaments  forming  the  firm, 
light,  and  compact  skeleton  of  the  hand  have 
been  elsewhere  described.    See  article  Hand, 

BONES  AND  JOINTS. 

In  the  amputation  of  the  metacarpal  bone  of 
the  thumb,  which  is  easily  performed  at  its 
articulation  with  the  trapezium,  the  edge  of  the 
knife  should  be  kept  close  to  the  ulnar  edge  of 
the  bone,  in  order,  if  possible,  to  avoid  wound- 
ing the  radial  artery  as  it  traverses  the  inter- 
osseous space.  The  metacarpal  bone  of  the 
little  finger  may  also  easily  be  removed  by  an 
operation  similar  to  that  practised  for  the 
thumb;  the  articulating  surfaces  are  nearly 
plane  and  inclined  obliquely  upwards  and 
inwards.  Disarticulations  may  also  be  per- 
formed of  the  other  metacarpo-carpal  joints; 
but  the  operations  are  very  difficult  and  em- 
barrassing, owing  to  the  irregularity  of  the 
articular  surfaces  and  their  close  connexions 
with  each  otter,  and  in  removing  them  singly 
a  much  neater  and  easier  plan  is,  if  their 
upper  extremities  are  sufficiently  sound,  to  saw 
through  them  in  an  oblique  direction. 

In  amputating  at  the  phalangeo-metacarpal 
articulations  the  flap  is,  if  possible,  made  on 
the  palmar  surface.  At  the  first  joint  of  the 
fingers  two  flaps  are  preserved  by  making  two 
semilunar  incisions,  which  extend  from  the 
head  of  the  metacarpal  bones  to  the  termination 
of  the  commissure  of  the  fingers,  meeting  be- 
hind and  before  at  the  joint,  which  is  an  inch 
above.  They  may  all  be  amputated  together 
when  a  single  flap  is  made  on  the  palmar  surface 
terminating  at  the  line  in  the  skin  that  bounds 

It  is  not  uncommon  for  these  tendons  to  send  a 
slip  to  the  superior  extremity  of  the  first  phalanx. 
VOL  II. 


the  commissure.  In  amputating  at  the  other 
joints  of  the  fingers  it  is  necessary  to  recollect 
the  marks,  before  alluded  to  when  speaking  of 
the  skin,  and  to  divide  the  lateral  ligaments 
before  entering  the  joints. 

(  F.  T.  M'Dougall.J 

HEARING,  ORGAN  OF.  The  ear  (in  the 
wide  acceptation  of  the  term).  Organon  auditHs 
s.  auris. — Fr.  Uorgane  de  Vouie  ou  Voreille. 
Germ.  Das  Gehororgan  oder  das  Ohr. — As 
the  apparatus  of  vision  naturally  admits  of 
being  divided  into  two  parts,  viz.  the  eye-ball 
and  its  appendages,  so  we  can  distinguish  in 
the  apparatus  of  hearing  a  fundamental  organ, 
and  parts  accessory  to  the  perfect  performance 
of  its  function.  The  fundamental  organ  of 
hearing  is  what  is  commonly  called  the  internal 
ear,  or  from  the  complexity  of  its  structure,  the 
labyrinth.  The  accessory  organs  consist  of  the 
middle  ear  or  tympanum  and  external  ear.* 

If  we  extend  our  observations  to  the  animal 
series,  and  trace  the  apparatus  of  hearing  along 
the  descending  scale,  we  shall  find  that  the 
accessory  parts  gradually  disappear,  and  that 
the  sense  of  hearing  comes  at  last  to  have  for 
its  organ  merely  a  representative  of  the  laby- 
rinth in  the  higher  animals.  This  part  even, 
having  laid  aside  much  of  its  complicated 
structure,  presents  itself  under  the  form  simply 
of  a  membraneous  pouch  containing  a  fluid, 
with  a  calcareous  concretion  suspended  in  it, 
on  which  the  auditory  nervous  filaments  are 
expanded. 

The  labyrinth  being  in  the  apparatus  of  hear- 
ing exactly  what  the  eye-ball  is  in  that  of  vision, 
may  be  distinguished  by  the  name  of  ear-bulb. 
The  ear-bulb,  like  the  eye-ball,  consists  of  a  hard 
external  case,  in  the  interior  of  which  are  con- 
tained membraneous  and  nervous  parts  and 
humours.  The  accessory  parts  of  the  apparatus 
of  hearing  have  also  their  prototypes  in  the 
accessory  organs  of  the  apparatus  of  vision. 

The  different  parts  of  the  apparatus  of  hear- 
ing are  situated  in  the  interior  and  on  the  sur- 
face of  the  temporal  bone.  See  the  description 
of  the  temporal  bone  in  the  article  Cranium. 

I. — The  ear-bulb,  or  fundamental  organ  of 
hearing.    ( Bulbe  auditif,  Breschet.) 

In  man  and  the  higher  animals,  the  hard  ex- 
ternal case  of  the  ear-bulb  is  of  bone,  and  is 
called  the  osseous  labyrinth.  The  soft  textures 
contained  in  its  interior  be;ir  the  name  of  mem- 
braneous labyrinth.  The  interior  of  the  osseous 
labyrinth,  which  we  may  with  Breschetf  call 
the  labyrinthic  cavity,  is  not  completely  filled 
by  the  membraneous  labyrinth  ;  the  remaining 
space  is  occupied  by  a  limpid  watery  fluid. 

1 .  The  osseous  labyrinth  (labyrinthus  osseus  ; 
Fr.  Labyrinthe  osseux ;  Germ.  Das  knocherne 
Labyrinth.) — The  osseous  labyrinth  presents 
three  compartments,  distinguished  by  the  names 

*  Haighton,  in  Memoirs  of  the  Medical  Society 
of  London,  vol.  iii.  p.  7.    London,  1792. 

+  Recherches  anatomiques  et  physiologiques  sur 
l'organe  de  1'ouie  et  sur  I'audition,  &c.  chap.  i.  s.  x. 
Paris,  1B36. 

2  N 


530 


ORGAN  OF  HEARING. 


of  vestibule,  semicircular  canals,  and  cochlea. 
The  semicircular  canals  and  cochlea  do  not  com- 
municate immediately  with  each  other,  but  only 
mediutely  through  the  vestibule.  The  latter 
may  be  considered  the  principal  compartment. 

The  osseous  labyrinth  is  imbedded  in  the 
substance  of  the  petrous  portion  of  the  temporal 
bone,  from  the  compact  texture  of  which  it  is, 
in  the  adult,  scarcely  to  be  distinguished.  In 
the  early  periods  of  life,  however,  its  walls  con- 
sist of  a  hard  but  brittle  osseous  substance, 
around  which  is  the  then  less  compact  tissue  of 
the  petrous  bone.  Hence  it  is  in  a  young  bone 
only,  and  that  by  means  of  some  little  prepara- 
tion, that  the  external  form  of  the  osseous  laby- 
rinth can  be  well  demonstrated. 

Of  the  compartments  of  the  osseous  laby- 
rinth, the  vestibule  lies  in  the  middle,  the  semi- 
circular canals  behind  it,  and  the  cochlea  in 
front. 


Fig.  232. 


The  exterior  of  the  osseous  labyrinth  of  the  left  side. 
Natural  size. 

a.  Oval  or  vestibular  fenestra  ;  b.  round  or 
cochlear  fenestra  ;  c.  external  or  horizontal  semi- 
circular canal ;  d.  superior  or  anterior  verlical  se- 
micircular canal;  e.  posterior  or  inferior  vertical 
semicircular  canal ;  f.  the  turns  of  the  cochlea. 

The  vestibule,  ( vestibulum  ;  Fr.  le  vestibule  ; 
Germ,  der  Vorhqf.) — The  vestibule  is  an  irre- 
gularly shaped  cavity,  the  diameter  of  which 
from  above  downwards,  as  also  from  behind 
forwards,  may  be  stated  to  be  about  one-fifth 
of  an  inch.  The  distance  between  its  inner 
and  outer  wall  is  somewhat  more  than  one- 
tenth  of  an  inch.  In  an  anatomical  sense  we 
can  distinguish  in  it  three  horns,  one  of  which 
is  towards  the  anterior  and  lower  part,  another 
towards  the  posterior  and  lower  part,  whilst 
the  third  composes  the  upper  part  of  the  vesti- 
bular cavity. 

The  anterior  and  lower  horn  leads  by  an 
oval  opening  directed  forwards  and  downwards 
into  the  vestibular  scala  of  the  cochlea.  This 
opening  is  called  the  vestibular  orifice  of  the 
cochlea,  osteum  s.  apertura  scala  vestibuli 
cochlea.  The  posterior  and  lower  horn  of  the 
vestibule  corresponds  to  three  of  the  orifices  of 
the  semicircular  canals ;  the  upper  horn  to 
the  other  two  orifices. 

At  the  under  part  of  the  inner  wall  of  the 
vestibule,  within  the  limits  of  its  anterior  horn 
and  to  the  inside  of  the  vestibular  orifice  of  the 
cochlea,  is  a  hemispherical  depression,  fovea 
hemispherica  s.  sub-rotunda.  Its  bottom,  which 
corresponds  to  the  posterior  part  of  the  lower 
depression  at  the  bottom  of  the  internal  audi- 
tory meatus,  presents  a  sieve-like  spot,  macula 
cribrosa,  that  is,  it  is  perforated  by  minute 
apertures  for  the  passage  of  filaments  of  the 
auditory  nerve.  On  the  upper  wall  of  the  ves- 
tibule, bordering  the  upper  margin  of  the  hemi- 


spherical fossa  and  within  the  limits  of  the 
upper  horn,  is  another  depression,  of  an  oval 
shape,  which  is  known  by  the  name  of  fovea 
hemi-elliptica.  The  hemispherical  and  hemi-el- 
liptical  depressions  are  separated  by  a  ridge  or 
pyramidal  eminence,  eminentia  pi/ramidalis, 
pervaded  by  small  canals  for  the  passage  also 
of  nervous  filaments.  On  the  inner  wall  of  the 
vestibule,  a  little  in  front  of  the  orifice  common 
to  the  two  vertical  semicircular  canals  and 
within  the  limits  of  the  posterior  horn,  there  is, 
bordering  on  the  hemi-elliptical  and  hemisphe- 
rical depressions,  below  the  former  and  behind 
the  latter,  another  very  small  depression  or 
sulcus,  fossa  s.  cavitas  sulciformis,  which  leads 
upwards  and  backwards  to  a  small  oblique 
orifice,  that  of  the  aqueduct  of  the  vestibule, 
osteum  internum  aqueductus  vestibuli.  At  the 
middle  of  the  inner  wall  of  the  vestibule,  where 
the  boundary  lines  of  these  three  depressions 
meet,  there  is  a  slight  eminence. 

The  inner  wall  of  the  vestibule  corresponds 
to  the  bottom  of  the  internal  auditory  meatus, 
and  is  pervaded  by  small  canals,  some  of  which 
have  been  already  mentioned,  for  the  passage 
of  fibrils  of  the  auditory  nerve  and  of  blood- 
vessels. 

In  the  outer  wall  of  the  vestibule  there  is  an 
oval,  or  rather  a  kidney  or  bean-shaped  hole, 
called  foramen  ovule,  s.  fenestra  ovalis,  s.  fenes- 
tra vestibuli.  The  long  diameter  of  this  aper- 
ture, which  is  about  one-tenth  of  an  inch  or 
perhaps  a  little  more,  is  directed  from  behind 
forwards.  Its  vertical  diameter  is  about  half 
that  of  its  long  diameter.  The  upper  part  of 
the  circumference  of  the  hole  is  arched  up- 
wards, the  lower  part  is  slightly  inclined  in  the 
same  direction.  The  margin  of  the  vestibular 
fenestra  is  turned  in  towards  the  vestibule. 
Viewed  from  the  tympanum,  into  which  it 
opens  in  the  macerated  bone,  the  vestibular 
fenestra  appears  situated  at  the  bottom  of  a 
fossa,  which  was  called  by  Cotugno  pelvis 
ovalis.  In  the  recent  state  the  vestibular  fene- 
stra is  closed  in  by  the  base  of  the  stapes. 

The  semicircular  canals,  (canales  semicircu- 
lares ;  Fr.  les  canaux  semicirculaires ;  Germ,  die 
Bogengdnge  oder  halbcirkelformigen  Candle.) 
These  are  three  canals,  which,  describing  more 
than  the  half  of  an  irregular  circle,  open  at  each 
of  their  extremities  into  the  vestibule ;  hence, 
if  it  was  not  for  the  circumstance  that  two 
unite  by  one  of  their  extremities  to  form  a 
common  short  canal,  there  would  be  in  the 
vestibule  six  orifices  of  semicircular  canals,  in- 
stead of  the  five  only  which  exist.  The  calibre 
of  these  canals  is  about  one-twentieth  of  an  inch 
in  the  direction  from  the  concavity  to  the  con- 
vexity of  their  curve ;  in  the  opposite  direction 
they  are  somewhat  compressed,  so  that  a  trans- 
verse section,  instead  of  presenting  a  round 
orifice,  presents  an  elliptical  one.  The  semicir- 
cular canals  are  wider  where  they  open  into  the 
vestibule,  but  especially  so  at  one  of  their  ex- 
tremities, which  presents  a  dilatation  in  the 
form  of  a  bulb,  called  ampulla  or  ampullary 
sinus,  sinus  ampullaceus. 

Two  of  the  semicircular  canals  occupy  a 
vertical  position  and  one  of  them  a  horizontal. 


ORGAN  OF  HEARING. 


531 


Of  the  vertical,  one  is  anterior  and  superior, 
the  other  posterior  and  inf  erior.  The  horizon- 
tal is  external. 

Superior  vertical  semicircular  canal,  canalis 
semicircularis  verticalis  superior.  The  superior 
vertical  semicircular  canal  has  its  arch  directed 
upwards,  and  its  extremities,  which  are  more 
widely  divergent  than  those  of  either  of  the 
other  two  semicircular  canals,  downwards.  Fol- 
lowed from  its  outer  extremity,  it  describes  its 
curve  from  without  and  upwards,  then  down- 
wards and  inwards,  with  an  inclination  from 
before  backwards, — in  a  word,  across  the  petrous 
bone.  The  convexity  of  the  curve  of  this  semi- 
circular canal  can  always  be  recognized  on  the 
upper  surface  of  the  petrous  bone.  The  con- 
cavity of  it  is  free  in  the  foetus  and  in  the  adult 
of  some  of  the  lower  animals,  as  the  dog,  hare, 
&c. 

The  inner  extremity  of  the  superior  vertical 
semicircular  canal  and  the  upper  extremity  of 
the  posterior  vertical  unite  to  form  a  common 
canal,  canalis  communis,  which  is  about  one- 
eighth  of  an  inch  long,  and  somewhat  wider 
than  either  of  the  two  which  unite  to  form  it. 

Posterior  vertical  semicircular  canal,  canalis 
semicircularis  verticalis  posterior.  Leaving  the 
common  canal,  the  posterior  vertical  semicircu- 
lar canal  describes  its  curve  parallel  to  the 
inner  and  posterior  surface  of  the  petrous  bone, 
perpendicularly  from  above  backwards,  then 
downwards  and  forwards.  The  convexity  of 
the  curve  is  thus  directed  backwards  and 
slightly  outwards,  its  extremities  forwards  and 
inwards. 

Horizontal  semicircular  canal,  canalis  semi- 
circularis horizontalis.  This  is  the  shortest  of 
the  three  canals  ;  traced  from  its  anterior  extre- 
mity, which  is  close  to  that  of  the  superior  ver- 
tical, it  curves  outwards  and  backwards,  then 
inwards  and  forwards.  Its  convexity  is  out- 
wards, its  extremities  directed  inwards. 

We  described  in  the  vestibule  three  horns, 
into  the  posterior  and  into  the  superior  of 
which  the  semicircular  canals  opened.  In  the 
superior  horn  is  observed  the  orifice  of  the  ex- 
ternal extremity  of  the  superior  vertical  semi- 
circular canal,  and  immediately  below  that  and 
above  the  fenestra  vestibuli,  the  orifice  of  the 
anterior  extremity  of  the  horizontal  semicircular 
canal.  Both  of  these  orifices  are  dilated  into 
ampullae.  In  the  posterior  horn  is  the  orifice 
of  the  canal  common  to  the  two  vertical  semi- 
circular canals.  Below  and  in  front  of  this 
orifice  is  the  opening  of  the  inferior  extremity 
of  the  posterior  vertical  semicircular  canal. 
Above  the  latter  and  immediately  outside  the 
former  is  the  opening  of  the  posterior  extremity 
of  the  horizontal.  Of  all  these  orifices  in  the 
posterior  horn,  that  of  the  lower  extremity  of 
the  posterior  vertical  semicircular  canal  is  the 
only  one  which  is  dilated  into  an  ampulla. 

There  are  thus  three  ampullary  dilatations, 
one  at  the  outer  extremity  of  the  superior  verti- 
cal semicircular  canal,  a  second  at  the  anterior 
extremity  of  the  horizontal,  and  the  third  at  the 
lower  extremity  of  the  posterior  vertical.  In 
the  lower  and  anterior  wall  of  the  ampullary 
sinus  of  the  posterior  vertical  semicircular  canal 


is  a  small  sieve-like  spot  indicating  the  entrance 
of  nervous  filaments. 

The  cochlea,  ( cochlea;  Fr.  le  limagon;  Germ. 
die  Schnecke. )—  The  cochlea  does  not  exist  in 
all  its  perfection  except  in  the  Mammifera.  In 
birds  it  is  in  a  very  rudimentary  state,  but  it  is 
easy  to  trace  parts  analogous  to  what  we  find 
in  the  Mammifera.  In  regard  to  frequency  of 
occurrence  in  the  animal  series,  the  cochlea 
does  not  stand  next  to  the  semicircular  canals  ; 
the  tympanum  is  found  in  a  greater  number  of 
animals. 

The  cochlea  forms  the  anterior  part  of  the 
labyrinth,  and  is,  perhaps  of  all  the  parts  of 
the  ear,  that  of  which  it  is  the  most  difficult  to 
give,  either  by  descriptions  or  delineations,  a 
correct  idea.  If  we  can  figure  to  ourselves  a 
tube  tapering  towards  one  extremity  where  it 
ends  in  a  cul-de-sac,  and  coiled,  like  the  shell 
of  a  snail,  round  an  axis  or  central  pillar;  and 
if  we  suppose  this  tube  subdivided  into  two 
passages  by  a  thin  partition  running  throughout 
its  length,  and  of  course  spirally  round  the 
axis,  we  shall  have  some  conception  of  the 
disposition  of  the  cochlea. 

The  tube  of  which  the  cochlea  is  composed, 
canalis  spiralis  cochlea,  is  about  an  inch  and  a 
half  long,  about  one-tenth  of  an  inch  in  dia- 
meter at  its  commencement,  and  about  one- 
twentieth  of  an  inch  at  its  termination.  It 
describes  two  turns  and  a  half,  and  that  in  a 
direction  from  below  upwards — from  left  to 
right  in  the  right  ear,  and  from  right  to  left  in  the 
left  ear.  The  apex  of  the  coil,  which  is  also  the 
apex  of  the  tube  itself,  is  directed  forwards  and 
outwards.  The  commencement  of  the  first 
turn  of  the  cochlea  forms  an  eminence  towards 
the  cavity  of  the  tympanum,  called  the  pro- 
montory. The  second  turn  lies  at  its  com- 
mencement within  the  first,  and  only  towards 
its  termination  rises  decidedly  above  the  level 
of  it.  By  the  base  of  the  tube  the  cochlea  is 
connected  with  the  vestibule.  The  cul-de-sac 
at  the  apex  forms  a  sort  of  vaulted  roof  called 
cupola. 

The  axis,  or  central  pillar,  modiolus  s.  colu- 
mella cochlea.  The  first  turn  of  the  cochlea 
takes  a  wider  circular  sweep  than  the  rest,  a 
sweep  having  an  average  diameter  of  a  quarter 
of  an  inch,  and  is  separated  from  the  second 
turn  by  the  interposition  of  a  soft  bony  sub- 
stance, which  extends  also  a  little  way  between 
the  second  and  third.  The  axis,  or  central 
pillar,  as  has  been  pointed  out  by  Ilg,*  is 
nothing  more  than  the  internal  walls  of  the 
tube  of  the  cochlea  and  the  central  space 
circumscribed  by  their  turns,  in  which  space 
the  filaments  of  the  cochlear  nerve,  running  in 
small  bony  canals,  are  contained.  Now  in  con- 
sequence of  the  wide  sweep  the  first  turn  of 
the  cochlea  takes  in  comparison  with  the  rest, 
the  axis  is  very  thick,  about  one-seventh  of  an 
inch,  where  it  is  surrounded  by  the  first  turn, 
and  rapidly  becomes  thinner  from  the  second 
onwards  to  its  termination.  The  last  part  of 
it  is  in  fact  formed  merely  by  the  fold  which 

*  Einige    anatomische     Beobachtungen,  etc. 
Prag.  1821,  p.  7. 

2  N  2 


532 


ORGAN  OF  HEARING. 


the  internal  wall  of  the  tube  of  the  cochlea  ne- 
cessarily forms'where  it  bends  abruptly  at  the 
last  turn.  This  last  part  of  the  axis,  viewed 
from  the  cavity  of  the  second  turn  of  the  tube, 
has  a  funnel-like  appearance,  the  wide  mouth 
corresponding  to  the  cupola;  hence  it  is  called 
infundibulum  or  sci/phus.  But  viewed  from  the 
last  turn,  the  so-called  infundibulum  is  a  mere 
free  edge  which  proceeds  directly  to  be  con- 
founded with  the  walls  of  the  cochlea.  But 
all  this,  if  the  disposition  of  a  snail's  shell,  or 
a  tube  coiled  round  be  rightly  conceived,  is 
understood  of  itself. 

Exposed  by  the  removal  of  the  outer  walls 
of  the  cochlea,  the  axis  is  somewhat  like  the 
common  pictorial  representations  of  the  tower 
of  Babel.  It  has  a  spongy  porous  appearance. 
It  is  pervaded  by  numerous  small  canals  which 
run  from  its  base  onwards  to  orifices  on  its 
sides,  corresponding  to  the  spiral  lamina,  and 
transmit  into  the  cochlea  the  ramifications  of 
the  cochlear  branch  of  the  auditory  nerve  and 
bloodvessels.  The  outermost  of  the  canals  are 
the  shortest;  towards  the  interior  they  gradually 
become  longer,  and  there  is  one  canal  in  parti- 
cular wider  than  the  rest,  twhich  runs  through- 
out its  whole  length  ;  it  is  called  tubulus  cen- 
tralis modioli,  and  opens  at  the  so-called  in- 
fundibulum. 

The  base  of  the  axis  corresponds  to  the  an- 
terior part  of  the  inferior  depression  at  the 
bottom  of  the  internal  auditory  meatus,  and 
presents  the  commencing  orifices  of  the  small 
canals  just  mentioned,  arranged  in  a  spiral 
manner  corresponding  to  the  turns  of  the  coch- 
lea, tractus  spirulis  f'oraminulentus  of  Co- 
tugno.* 

Spiral  lamina  and  scala  of  the  cochlea. — 
The  passages  into  which  the  tube  of  the  coch- 
lea is  subdivided  are  called  scala,  and  the  par- 
tition lamina  spiralis. 

The  spiral  lamina  is  partly  bony,  partly 
membraneous;  but  as  we  are  describing  the 
osseous  shell  of  the  labyrinth  only,  it  is  with 
the  bony  part  alone  we  have  at  present  to  do. 
The  bony  part  of  the  spiral  lamina,  zonula  ossea 
lamina:  spiralis,  is  coiled  round  the  axis  or  cen- 
tral pillar  of  the  cochlea  like  the  stairs  in  a 
spiral  staircase.  The  internal  or  central  margin 
of  the  bony  spiral  lamina  is  inserted  on  the 
axis.  Its  peripheral  margin  is  free  in  the  dry 
bone,  so  that  the  two  scalae  are  not  found  com- 
pletely separated  from  each  other,  as  in  the  re- 
cent state,  when  the  membraneous  extension  of 
the  spiral  lamina  exists.  At  the  place  where 
the  spiral  lamina  is  inserted  on  the  axis,  there 
is  a  sort  of  canal  all  round,  which  has  been 
specially  described  by  Rosenthal!  under  the 
name  of  canalis  spiralis  modioli. 

The  spiral  lamina  commences  with  a  bend 
or  sweep  upwards  and  forwards  at  the  base  of 
the  cochlea,  below  the  hemispherical  depres- 
sion of  the  vestibule  and  opposite  the  bridge  of 
bone  which  separates  the  vestibular  fenestra 

*  De  aqueductibus  auris  humanae  interna?  ana- 
tomies dissertatio,  s.  xxiv.  pp.  36—38.  Viennae, 
1774. 

f  Ueber  den  Ban  der  Spindel  im  menschlichert 
Ohr.    In  Meckel's  Archiv.  Bd.  viii.  p.  75. 


from  the  cochlear  fenestra.  Its  broadest  part, 
which  is  about  the  middle  of  the  first  turn  of 
the  cochlea,  is  about  one-twentieth  of  an,  inch. 
Towards  the  summit  of  the  cochlea  it  insen- 
sibly contracts,  and  ceasing  to  be  connected 
to  the  axis,  where  the  latter  presents  the  free 
margin  already  mentioned,  terminates  at  the 
commencement  of  the  third  turn  in  a  curved 
hook-like  point.  This  hook,  hamulus  lamina: 
spirulis,  has  a  free  concave  margin  towards  the 
axis,  and  a  convex  margin,  which  latter,  how- 
ever, like  the  rest  of  the  peripheral  margin  of 
the  bony  spiral  lamina,  is  not  free  in  the  recent 
state,  but  is  continuous  with  the  membrane 
which  completes  the  partition. 

In  consequence  of  the  above  mode  of  termi- 
nation of  the  bony  spiral  lamina  by  means  of 
a  free  margin  towards  the  axis  of  the  cochlea, 
an  opening  of  communication  is  left,  even  in 
the  recent  state,  between  the  two  scalae  of  the 
cochlea.  For  this  opening,  which  was  called 
by  Cassebohm*  canalis  scularum  communis,  we 
adopt  from  Breschet-j-  the  name  helicotrema.\ 

The  bony  spiral  lamina  consists  of  two  thin 
plates  of  bone,  between  which  run  numerous 
small  canals  from  the  central  margin  of  the 
lamina  to  its  peripheral— the  continuation  of 
those  already  described  in  the  axis,  and  which 
therefore  bend  at  a  right  angle  in  passing  from 
the  axis  into  the  spiral  lamina.  At  the  free 
edge  of  the  osseous  part  of  the  spiral  lamina, 
the  two  plates  of  bone  are  intimately  incorpo- 
rated. This  part  of  the  bony  spiral  lamina, 
which  is  more  delicate,  denser,  whiter,  more 
transparent,  and,  in  the  recent  state,  more 
elastic  than  the  rest,  is  what  Breschet  calls  the 
middle  zone.  The  surface  of  the  spiral  lamina 
corresponding  to  the  tympanic  scala  is  much 
marked  with  striae  running  from  the  inner 
margin  to  the  outer.  The  surface  correspond- 
ing to  the  vestibular  scala  is  less  striated. 

Of  the  two  scalae  of  the  cochlea,  one,  scala 
tympani,  communicates  with  the  cavity  of  the 
tympanum  through  the  fenestra  rotunda  or 
cochlear  fenestra,  which  however,  in  the  recent 
slate,  is  closed  by  a  membrane ;  the  other, 
scala  veslibuli,  opens  by  an  oval  orifice  freely 
into  the  vestibule,  and  it  is  only  by  means  of 
the  communication  which  the  tympanic  scala 
has  with  the  vestibular  scala  through  the  heli- 
cotrema  that  the  former  communicates  with  the 
rest  of  the  labyrinthic  cavity.  The  tympanic 
scala  is  wider  at  the  commencement  than  the 
vestibular,  which  on  its  part  again  is  larger 
toward  the  termination.  Near  the  fenestra  ro- 
tunda there  is  in  the  tympanic  scala  a  very 
minute  orifice,  that  of  the  aqueduct  of  the 
cochlea.  We  shall  return  to  the  spiral  lamina, 
the  scalae  of  the  cochlea,  and  the  mechanism  of 
the  helicotrema,  when  speaking  of  the  mem- 
brane lining  the  labyrinthic  cavity. 

The  aqueducts. — What  are  called  the  aque- 
ducts are  two  canals  of  very  minute  calibre, 
opening  by  one  extremity  in  the  labyrinthic 

*  Tractatus  quintus  anat.  de  aure  humana,  etc. 
HaUe  Magd.  1735,  s.  194,  p.  12. 
t  Op.  cit.  s.  xiv. 

\  E?u£,  tXia-j-ai,  volvere,  and  rfripa,  foramen. 


ORGAN  OF  HEARING. 


533 


cavity,  and  by  the  other  on  the  surface  of  the 
petrous  portion  of  the  temporal  bone.  They 
are  generally  associated  with  the  name  of  Co- 
tugno,*  who,  though  not  their  discoverer,  was 
the  first  to  give  a  complete  description  of  them. 
One,  called  aqueductus  vestibuli,  communicates 
with  the  vestibule ;  the  other,  aqueductus  cock- 
Lea,  with  the  tympanic  scala  of  the  cochlea. 

The  internal  orifice  of  the  aqueduct  of  the 
vestibule  is  observed  to  commence  by  a  groove 
or  sulcus,  the  sulciform  depression  already  de- 
scribed in  the  vestibule,  immediately  below 
and  in  front  of  the  opening  common  to  the  two 
vertical  semicircular  canals.  From  this  the 
aqueduct  turns  itself  round  the  inner  wall  of 
the  common  canal,  and  then  follows  a  course 
downwards  and  backwards.  Gradually  widen- 
ing, it  opens  under  that  sort  of  osseous  scale 
observed  a  little  behind  the  middle  of  the  pos- 
terior and  inner  surface  of  the  petrous  bone, 
just  above  the  jugular  fossa  ;  towards  the  latter 
there  is  usually  a  groove  running  on  the  surface 
of  the  bone  from  the  orifice  of  the  aqueduct. 
The  length  of  the  course  of  the  aqueduct  of 
the  vestibule  is  about  one-third  of  an  inch. 

The  aqueduct  of  the  cochlea  commences  by 
a  very  small  orifice  in  the  lower  wall  of  the 
scala  tympani  immediately  before  the  fenestra 
rotunda.  It  proceeds  downwards,  inwards, 
and  forwards,  in  the  inner  wall  of  the  jugular 
fossa  of  the  temporal  bone,  and  widening  in 
its  course  it  opens  at  the  bottom  of  that  tri- 
angular pyramidal  depression,  situated  towards 
the  middle  of  the  edge  which  limits  the  inner 
and  inferior  surfaces  of  the  petrous  bone,  and 
below  the  internal  auditory  meatus.  The 
length  of  its  course  is  about  a  quarter  of  an  inch. 
The  aqueduct  of  the  cochlea  is  very  wide  in 
the  pig.  Of  the  aqueducts  we  shall  observe 
farther  in  speaking  of  the  membrane  lining 
the  labyrinthic  cavity. 


Fig  233. 


The  labyrinthic  cavity  of  the  right  side,  magnified 
two  diameters. 


a.  superior  horn  of  the  vestibule  ;  b.  posterior 
and  inferior  horn;  r.  anterior  and  inferior  horn 
leading  into  the  cochlea ;  rf.  hemispherical  depres- 
sion ■,  e.  hemi-ellipiical  depression  ;  f.  pyramidal 
elevation  bet  ween  the  two  having  a  porous  sieve  - 
like  appearance  from  being  pervaded  by  canals  for 
the  passage  of  nervous  filaments  •,  t/.  superior 
vertical  semicircular  canal ;  It.  its  ampullavy  dila- 
tation ;  t.  posterior  vertical  semicircular  canal  ; 
k.   its  ampullary  dilatation ;   /.  canal  common  to 


the  superior  and  posterior  vertical  semicircular 
canals  ;  m.  orifice  by  which  the"  common  canal 
opens  into  the  vestibule  ;  n.  horizontal  semi- 
circular canal ;  o.  its  ampullary  dilatation ;  p. 
vestibular  orifice  of  the  aqueduct  of  the  vestibule  ; 
q.  osseous  part  of  the  spiral  lamina,  seen  from  the 
surface  which  corresponds  to  the  vestibular  scala; 
r  r.  space  which  is  occupied  by  the  membraneous 
part  of  the  spiral  lamina;  s.  hamulus  or  hook  in 
which  the  bony  spiral  lamina  ends;  t.  helico- 
trema;  u.  substance  of  the  petrous  bone,  between 
the  first  turns  of  the  cochlea;  v.  orifice  of  the  aque- 
ductus cochleae. 

Membrane  lining  the  labyrinthic  cavity. — 
The  cavities  of  the  osseous  labyrinth  which  we 
have  just  described  are  lined  by  a  serous  or 
fibro-serous  membrane,  extremely  delicate  and 
closely  adherent  to  the  surfaces.  The  mem- 
braneous labyrinth  must  not  be  confounded  with 
it.  This  membrane,  which  may  be  compared 
to  that  serous  pellicle  on  the  inner  surface  of 
the  sclerotica,  known  by  the  name  of  mem- 
brana  fusca  or  arachrioidea  oculi,  is  more 
manifest  at  an  early  age  than  in  adults,  and  is 
nowhere  so  distinct  as  at  the  places  where  the 
nerves  enter,  and  at  the  bottom  of  the  tym- 
panic scala  of  the  cochlea.  It  is  it  which 
completes  the  spiral  septum  of  the  cochlea,  by 
an  arrangement  immediately  to  be  described. 

The  fenestra  rotunda  or  cochlear  fenestra  is, 
in  the  recent  state,  closed  by  a  membrane 
which  shuts  out  the  cavity  of  the  tympanum 
from  any  direct  communication  with  the 
cochlea.  This  membrane,  called  by  Scarpa  * 
the  secondary  membrane  of  the  tympanum, 
membrana.  tympani  secundaria,  is  concave  to- 
wards the  cavity  of  the  tympanum,  convex 
towards  the  tympanic  scala  of  the  cochlea,  and 
is  received  at  its  circumference  into  a  groove 
within  the  orifice  of  the  fenestra  rotunda.  It 
is  composed  theoretically  of  three  layers,  the 
inner  of  which  is  nothing  but  the  fibro-serous 
membrane  under  consideration.  The  outer 
layer  is  a  continuation  of  that  which  lines  the 
cavity  of  the  tympanum.  The  third  and  pro- 
per layer  is  situated  between  the  two  men- 
tioned. The  same  may  be  said  in  regard  to 
that  membrane,  which,  together  with  the  base 
of  the  stapes,  closes  the  vestibular  fenestra. 

The  membrane  lining  the  tympanic  scala 
of  the  cochlea  is  continued  into  that  lining  the 
vestibular  scala  at  the  opening  called  heli- 
cotrema.  The  membrane  of  the  vestibular 
scala  is  continuous  with  that  lining  the  vesti- 
bule, which  on  its  part  is  continuous  with  that 
of  the  semicircular  canals.  Lastly,  the  same 
membrane  lines  the  aqueducts. 

Such  is  a  general  description  of  the  mem- 
brane lining  the  labyrinthic  cavity;  but  to 
understand  the  disposition  of  the  cochlea  and 
aqueducts  in  the  recent  state,  we  must  take  a 
nearer  view  of  this  membrane  such  as  it  exists 
in  those  cavities,  which,  indeed,  is  the  must 
important  and  difficult  part  of  it. 

Of  the  cochha  in  the  recent  state. — The 
cochlea  is  the  last  addition  made  to  the  laby- 
rinth in  the  ascending  scale  of  the  animal 
series.  As  was  said,  it  is  in  birds  in  a  very  ru- 


*  Op.  cit. 


*  De  atiditu  ct  olfactu,  cap.  li.  s.  19.  p.  35. 


534 


ORGAN  OF  HEARING. 


dimentary  state.  It  is  in  fact  a  mere  pouch 
or  diverticulum  not  at  all  coiled  up,  in  which, 
however,  can  be  distinguished  a  part  corres- 
ponding to  a  lamina  spiralis,  which  is  repre- 
sented by  a  cartilage,  and  a  vestibular  and  a 
tympanic  scala,  together  with  a  cochlear  fe- 
nestra. This  analogy,  much  insisted  on  by 
Breschet,*  I  gave  a  brief  notice  of  some  years 
ago.f 

The  cochlea  is  richly  supplied  with  nerves. 
The  spiral  lamina  is  that  part  of  it  on  which 
its  nerves  expand ;  this  must  therefore  be  con- 
sidered as  forming  a  very  essential  element  of 
the  cochlea,  and  may  be  viewed  as  being  in 
the  economy  of  that  part  of  the  internal  ear 
what  the  apparatus  of  the  membraneous  laby- 
rinth is  to  the  vestibule  and  semicircular 
canals. 

The  bony  spiral  lamina  is  rendered  a  com- 
plete partition  between  the  scalae  of  the  cochlea 
by  a  membraneous  continuation,  zonula  mem- 
brarwcea  lamina  spiralis  s.  zona  Valsalva, 
formed  by  the  application  against  each  other 
of  the  membranes,  which  line  the  interior  of 
the  two  scalae,  at  the  moment  they  are  reflected 
from  the  free  edge  of  the  bony  spiral  lamina 
to  the  outer  walls  of  the  cochlea.  Hence  the 
spiral  partition  of  the  cochlea,  when  complete, 
is  osseous  at  its  inner  or  central  part,  and  mem- 
braneous at  its  outer  or  peripheral. 

The  outer  part  of  the  osseous  zone  of  the 
spiral  lamina  is  thinner  than  the  rest ;  it  is 
semi-osseous,  semi -membraneous,  and  the 
membraneous  spiral  lamina  at  its  junction 
with  it  presents  a  fine  cartilaginous  stripe  ; 
hence  Comparetti  and  Sommerrmg  described 
the  spiral  lamina  as  composed  of  concentric 
bands  or  zones.  They  admitted  four,  viz.  1, 
the  inner  thick  part  of  the  bony  spiral  lamina  ; 
2,  the  outer  thin  part;  3,  the  cartilaginous 
stripe  commencing  the  membraneous  spiral 
lamina ;  and  4,  the  rest  of  the  membraneous 
spiral  lamina,  or  the  membraneous  spiral  la- 
mina properly  so  called.  The  first  zone  is  con- 
tinued into  the  hamulus  cochlete,  the  second 
ceases  towards  the  second  turn  of  the  cochlea, 
and  the  third  and  fourih  are  continued  beyond 
the  hamulus  cochlea,  forming  of  themselves 
the  spiral  partition  in  the  last  turn. 

It  is  sufficient  to  admit,  with  Breschet,}  only 
three  zones  ;  an  osseous  zone,  a  middle  zone, 
and  a  membraneous  zone  ;  the  third  and 
fourth  zones  of  Comparetti  being  compre- 
hended under  the  latter. 

The  osseous  zone  of  the  spiral  lamina  we 
have  already  described,  and  alluded  to  the 
middle  zone.  The  latter,  when  it  still  exists 
in  the  dry  bone,  appears  merely  as  the  outer 
margin  of  the  former.  It  is  the  narrowest  of 
the  three  zones,  and  is  most  distinct  in  the  first 


*  Op.  cit.  and  also  Recherches  Anatomiques  et 
Physiologiques  sur  Forgane  de  l'audition  chez  les 
Oiseaux.  Paris,  1836. 

f  "  Note  on  the  ear  of  Birds,"  in  the  first  and 
only  volume  of  the  second  series  of  the  Edinburgh 
Journal  of  Natural  and  Geographical  Science. 
Edinburgh,  1831. 

|  Op.  cit.  chap.  ix.  s.  cxcix. 


Fig.  234. 


B 


The  axis  of  the  cochlea  and  spiral  lamina  isolated, 
in  order  to  show  the  disposition  of  the  three  zones. 
The  vestibular  lamina  of  the  osseous  zone  is  re- 
moved.   (  From  Breschet.) 

A,  natural  size.  B,  magnified. 
a.  trunk  of  the  cochlear  nerve  ;  4.  distribution  of 
the  filaments  of  this  nerve  in  the  osseous  zone  ; 
c.  nervous  anastomoses  in  the  middle  zone ;  d. 
membraneous  zone  ;  e.  osseous  substance  of  the 
axis ;  /.  helicotrema  or  hole  of  communication 
betwixt  the  two  scalae. 

turn  of  the  cochlea.  Breschet  describes  it  as 
composed  of  the  membranes  lining  the  interior 
of  the  two  scalae,  where  they  first  meet  each 
other  in  passing  from  the  bony  spiral  lamina, 
together  with  osseous  particles  deposited  be- 
tween them.  In  this  interstice  between  the 
membranes  also  are  contained  the  last  rami- 
fications of  the  filaments  of  the  cochlear  nerve, 
still  enveloped  by  their  neurilemma,  and 
sprinkled  over  by  the  small  bony  particles  just 
mentioned. 

Different  from  the  middle  zone,  the  mem- 
braneous zone  goes  on  increasing  in  breadth, 
though  not  regularly,  from  the  base  to  the 
summit  of  the  cochlea.  It  is  the  longest  and 
most  extensive  of  the  three  zones.  It  is  it 
alone  which  extends  into  the  last  turn  of  the 
cochlea.  According  to  Breschet  the  mem- 
braneous zone  should  be  composed  of  three 
layers,  the  two  exterior  of  which  should  be, 
as  already  said,  formed  by  the  membranes 
lining  the  interior  of  the  seals,  and  the  mid- 
dle one  by  the  expansion  and  interlacing  of  the 
neurilemmatic  sheaths  from  the  middle  zone ; 
but  these  layers  are  so  thin  and  so  closely 
united  that  they  are  inseparable,  and  constitute 
a  membrane  of  great  thinness  and  transparency, 
on  which,  however,  bloodvessels  can  be  easily 
seen. 

The  membraneous  zone  presents  a  central 
margin  continuous  with  the  rest  of  the  spiral 
lamina,  except  in  the  third  turn  of  the  cochlea, 
where  this  margin  forms  nearly  the  third  of 
the  circumference  of  the  helicotrema,  and 
where  it  runs  into  the  peripheral  margin  at  an 
acute  angle.  The  peripheral  margin,  which 
is  much  thicker  than  the  rest  of  the  mem- 
braneous zone,  is  pervaded  by  a  vascular  sinus, 
like  that  which  in  the  eye  runs  round  the 
circumference  of  the  cornea  at  the  insertion  of 
the  iris. 


ORGAN  OF  HEARING. 


535 


Fig.  235. 


A  diagram  from  Breschet,  intended,  according  to  him,  to  give  an 
exact  idea  of  the  disposition  of  the  helicotrema.  The  walls 
of  the  vestibular  scala  are  supposed  to  be  removed. 

a  a  a.  represent  the  osseous  and  middle  zone  of  the  spiral 
lamina ;  its  termination  in  the  hamulus  or  hook  is  seen  ; 
b  b  b  b.  this  darker  and  narrower  stripe  represents  the  mem- 
braneous zone  of  the  spiral  septum  ;  towards  the  summit  of 
the  cochlea  it  becomes  a  little  broader,  and  at  its  termination 
constitutes  by  itself  alone  the  septum  between  the  two  seals 
at  their  termination  ;  c.  the  commencement  of  the  tympanic 
scala  ;  d.  the  external  or  great  margin  ;  e.  the  internal  mar- 
gin of  the  turns  of  the  cochlea  ;  the  two  margins  d  and  e 
meet  at  o ;  fff  the  vacant  space  corresponding  to  the  axis  ; 
it  terminates  at  o,  which  corresponds  to  the  summit  of  the 
axis;  x.  helicotrema  or  hole  which  establishes  a  communica- 
tion between  the  two  scalae. 


The  section  of  the  peripheral  margin  of  the 
membraneous  zone  presents  a  triangular  sur- 
face, the  base  of  which  is  inserted  on  the  osse- 
ous wall  of  the  cochlea.  This  swollen  margin 
of  the  membraneous  zone  is,  according  to 
Breschet,  evidently  continuous,  at  the  origin 
of  the  spiral  lamina  in  the  base  of  the  cochlea, 
with  the  osseous  zone,  a  circumstance  which 
is  particularly  to  be  remarked  in  very  young 
foetuses,  where  all  these  parts  are  still  cartila- 
ginous. This  thickened  margin  of  the  mem- 
braneous zone  Breschet  therefore  considers  as 
analogous  to  the  tympanic  cartilage  of  the 
bird's  cochlea,  having  exactly  the  same  rela- 
tions and  uses. 


pared  to  the  tympanic  cartilage  of  birds  ; 
/.  scala  vestibuli ;  g.  scala  tympani ;  h. 
periosteum  lining  the  vestibular  scala, 
more  vascular  than  fibrous ;  i.  peri- 
osteum of  the  tympanic  scala ;  j.  nerve. 

In  vascularity  and  richness  in 
nerves,  the  spiral  lamina  bears  a 
great  resemblance  to  the  iris.  Like 
it,  also,  it  is  the  partition  between 
two  chambers,  containing  an  aque- 
ous humour,  and  communicating, 
like  the  aqueous  chambers  of  the  eye, 
by  a  single  orifice. 

The  two  scala;  of  the  cochlea  have 
not  the  same  length  nor  the  same 
diameter.  Toward  the  base  of  the 
cochlea  the  tympanic  scala  exceeds 
somewhat  the  vestibular;  its  diameter 
is,  at  the  same  time,  also  a  little  more 
considerable,  as  far  as  towards  the 
middle  of  the  first  turn  of  the  spire. 
The  two  scalse  have  then  the  same 
diameter,  and  preserve  the  equality 
to  the  commencement  of  the  last  turn. 
There  the  tympanic  scala  contracts, 
and  in  particular  flattens  considerably, 
and  is  at  last  confounded,  through  the 
helicotrema,  with  the  vestibular  scala, 
which  still  continues  for  two-thirds  of 
a  turn,  and  then  ends  in  a  cul-de-sac. 
This  is  also  to  be  noted  in  regard  to 
the  vestibular  scala  of  the  bird's  coch- 
lea, which  indeed  is  very  large,  and 
proceeds  considerably  beyond  the  tym- 
panic scala.  It  ends  in  a  large  cul-de- 
sac  called  lagena. 


Fig.  236. 


Diagram  of  a  transverse  section  of  the  two  tcalee  of 
the  cochlea  (from  Breschet). 

a.  a.  osseous  wall  ;  b.  osseous  zone  compared  to 
the  vestibular  cartilage  of  the  cochlea  of  birds  ;  c. 
middle  zone  compared  to  the  audilive  lamellae ; 
d.  membraneous  zone  ;  e.  cartilaginiform  swelling  of 
the  external  margin  of  the  membraneous  zone,  com- 


A  section  of  the  cochlea  parallel  to  the  direction  of 
its  axis,  in  order  to  show  the  disposition  of  the  whole 
of  its  parts.  Magnified.    ( From  Breschet.) 

a.  a.  a.  trunk  of  the  cochlear  nerve  ;  b.  b.  fila- 
ments of  this  nerve  in  the  osseous  zone  ;  c.  c.  c.  c. 
nervous  anastomoses  in  the  middle  zone  ;  d.  d.  d.  d, 
membraneous  zone  ;  e.  e.  e.  e.  swelling  of  the  exter- 
nal margin  of  the  membraneous  zone;  1,  1,  axis 
of  the  cochlea;  2,  infundibulum ;  3,  3,  3,  3,  exter- 
nal osseous  wall  of  the  cochlea  ;  4,  4,  4,  4,  osseous 
lamina  separating  the  turns  of  the  spire  of  the 
cavity  of  the  cochlea  ;  5,  5,  5,  5,  tympanic  lamella 
of  the  osseous  zone  of  the  spiral  lamina  ;  6.  vesti- 
bular lamella;  7,  hamulus  or  hook,  which  ter- 
minates the  osseous  zone  ;  8,  helicotrema,  with  a 
bristle  introduced  into  it. 


536 


ORGAN  OF  HEARING. 


Farther  observations  on  the  aqueducts. — The 
aqueducts,  the  one  leading  from  the  vesti- 
bule, and  the  other  from  the  tympanic  scala  of 
the  cochlea,  are  lined  by  a  continuation  of  the 
thin  and  delicate  pellicle  which  invests  the  in- 
terior of  those  cavities. 

Under  the  osseous  scale,  on  the  surface  of 
the  petrous  bone,  where  the  aqueduct  of  the 
vestibule  ends,  there  is  a  small  triangular  pouch 
produced  by  a  separation  of  the  dura  mater  into 
two  layers.  Into  this  pouch  the  lining  mem- 
brane of  the  aqueduct  enters,  and  ends  in  a 
cul-de-sac.  The  pouch  is  called  by  Cotugno 
the  membraneous  cavity  of  the  aqueduct.  I 
found  the  structure  just  described  of  unusual 
size,  in  consequence  of  irregular  development, 
in  the  ear  of  a  man  deaf  and  dumb  from  birth, 
which  I  examined  some  years  ago.  The  trian- 
gular pouch  in  the  dura  mater  was  about  one- 
third  of  an  inch  long  at  its  sides,  and  was  dis- 
tended by  a  clear  liquid.  Every  time  pressure 
was  made  on  the  distended  pouch,  a  fine  jet  of 
liquid  issued  through  a  small  opening  which 
had  been  made  in  the  superior  vertical  semicir- 
cular canal.  Similar  cases  have  been  described 
by  Mondini*  and  others. 

The  lining  membrane  of  the  aqueduct  of  the 
cochlea  ends,  in  like  manner,  in  a  cul-de-sac, 
which,  however,  is  not  so  large  as  that  of  the 
aqueduct  of  the  vestibule. 

The  liquid  contained  in  the  labyrinthic  ca- 
vity, or  liquid  of  Cotugno,  or  perilymph. 
( Aquula  Cotunnii.) — The  cavities  of  the 
osseous  labyrinth  contain  a  liquid,  the  secre- 
tion, probably,  of  their  thin  and  delicate 
lining  membrane.  They  contain  m>  air, 
as  has  been  asserted.  The  liquid  called  the 
liquid  of  Cotugno,  or  by  De  Blainville  peri- 
lymph, must  not  be  confounded  with  ano- 
ther which  is  contained  in  the  interior  of  the 
membraneous,  labyrinth.  Dominico  Cotugno,^ 
though  not  actually  the  discoverer  of  this  liquid, 
yet  took  a  more  correct  view  of  it  than  his  pre- 
decessors in  this  branch  of  anatomical  research, 
Valsalva,!  Vieussens,§  Cassebohm,||  and  Mor- 
gagni.H  He  in  fact  recognised  in  it  a  substance 
fulfilling  some  office  in  the  exercise  of  hearing, 
a  view  of  the  matter  which  was  admitted  by 
I  Jailer,  and  put  beyond  doubt  by  Ph.  Fr. 
Meckel,**  and  since  their  time  recognised  by 
all  physiologists. 

The  perilymph  occupies,  in  the  vestibule  and 
semicircular  canals,  all  the  space  not  taken  up 
by  the  membraneous  labyrinth.  The  cochlea 
contains  nothing  but  it ;  and  as  all  the  cavi- 

*  Comment.  Bonon.  torn.  vii.  Anatomia  Surdi 
Nati.  p.  422. 

t  De  Aqueductibus  Auris  Humans  Anatomica 
Dissfrtatio,  s.  xxix.-xxxi.    Neapoli,  1760. 

{  De  Aure  Humana  Tractatus,  &c,  cap.  iii.  s.  17, 
p.  79.    Trajecti  ad  Rhenum,  1707. 

§  Traite  Nouveau  de  la  Structure  de  l'oreille,  p. 
75.    Toulouse,  1714. 

||  Tractatus  Quintus  Anatomicus  de  Aure  Hu- 
mana, &c,  pp.  20-21.  De  Labyrintho.  Hals  Magd. 
1735. 

1;  Epist.  Anatom.  xii.  s.  64,  p.  469.  Venetiis 
1740. 

*•  Dissertatio  Anatomico-Physiologica  de  Laby- 
rinthi  Auris  Cont-ntis,  &c.    Argentorati,  1777,  s.  8. 


ties  of  the  osseous  labyrinth  communicate,  it  is 
the  same  humour  in  each. 

In  all  fishes,  except  thecartilaginous  with  fixed 
gills,  the  labyrinthic  cavity  is  very  imperfect, 
being  in  many  of  them  open  towards  the  cranial 
cavity,  or  at  the  most  separated  from  it  only  by 
a  membraneous  partition,  as  in  the  cod ;  hence 
the  encephalic  liquid  in  some  of  them  is  not  dis- 
tinct from  the  perilymph  whose  function  it  must 
perforin.  In  thecartilaginous  fishes  with  fixed 
gills,  on  the  contrary,  the  labyrinthic  cavity  is 
completely  separated  from  the  cranial ;  therefore 
in  them  we  meet  with  perilymph  distinct  from 
the  encephalic  liquid,  and  that,  too,  in  pretty 
large  quantity. 

In  birds  the  perilymph  is  in  much  less  quan- 
tity than  in  the  mammifera,  in  proportion  to  the 
size  of  the  membraneous  labyrinth.  In  rep- 
tiles the  quantity  of  perilymph  is  still  less. 

Cotugno  and  Meckel  supposed  that  the 
aqueducts  were  a  sort  of  diverticula,  or  cavi- 
ties which  served  to  let  off  the  superabundant 
perilymph,  when  necessary,  during  the  act  of 
hearing.  This  opinion  is,  however,  now-a-days 
very  much  questioned,  and  several  anatomists, 
Brugnone,  Ribes,  Breschet,  &c,  refuse  to  those 
aqueducts  the  uses  which  Cotugno  assigned 
them,  and  consider  them  merely  as  canals  des- 
tined for  the  passage  of  bloodvessels.  Although 
they  may  be  insignificant  in  a  physiological 
point  of  view,  still,  if  the  description  I  have 
given  of  them  be  correct,  they  must  be  consi- 
dered as  something  more  than  mere  canals  for 
the  transmission  of  vessels.  The  constancy  of 
the  aqueducts,  moreover,  is  another  argument 
against  their  being  mere  vascular  canals. 

Breschet,*  and  in  Hildebrandt's  Anatomieby 
Weberf  the  same  idea  is  concisely  expressed, 
explains  the  mode  of  formation  of  the  aque- 
ducts by  supposing  that  at  first  the  labyrinthic 
cavity  is  nothing  but  a  sac  formed  by  a  prolon- 
gation of  the  dura  mater  in  the  same  way  as  the 
tunica  vaginalis  is  of  the  peritoneum  ;  that  as 
development  proceeds,  the  tube  of  communi- 
cation between  the  labyrinthic  sac  of  the  dura 
mater  and  general  cavity  of  the  dura  mater  is 
gradually  contracted  and  elongated  ;  and  that  as 
ossification  extends,  the  tube  becomes  sur- 
rounded by  osseous  substance,  and  presents 
itself  under  the  appearance  of  an  aqueduct. 

"This  view,"  says  Breschet,  "is  rendered 
probable,  for  in  many  fishes  the  labyrinthic 
cavity  forms  one  with  that  of  the  cranium, 
and  if,  in  these  animals,  a  prolongation  of  the 
walls  of  the  cranium  tended  to  separate  the 
brain  from  the  ear,  there  would  result  a  small 
canal  establishing  a  communication  between 
the  two  cavities,  and  this  canal  would  be 
nothing  but  an  aqueduct." 

According  to  this  view,  the  lining  membrane 
of  the  labyrinthic  cavity  may  be  considered  as 
a  continuation  of  the  arachnoideal  layer  of  the 
dura  mater,  perhaps  of  the  dura  mater  also. 

2.  The  membraneous  labyrinth,  ( labyrinthus 
membranaceus.  Fr.  Lubyrinthe  membraneux. 
Germ.  Das  hdutige  Labyrinth.) — Within  the 

*  Op.  cit. 

t  Hand  iv.  p.  32. 


ORGAN  OF  HEARING. 


537 


osseous  labyrinth  is  contained  an  extremely 
delicate  and  complicated  membiano  -  ner- 
vous apparatus,  called  membraneous  laby- 
rinth, first  properly  described  by  Scarpa.* 
It  does  not  extend  into  all  the  compartments 
of  the  osseous  labyrinth,  but  only  occupies  the 
vestibule  and  semicircular  canals.  The  coch- 
lea, as  has  been  said,  contains  in  its  cavity 
nothing  but  perilymph. 

The  vestibular  part  of  the  membraneous 
labyrinth,  and  of  that  perhaps  one  of  the 
pouches  only,  is  all  that  is  really  fundamental 
in  the  structure  of  an  organ  of  hearing.  In 
the  Crustacea  and  Cephalopodous  Mollusca  in 
which  the  organ  of  hearing  exists  in  its  sim- 
plest form,  and  even  in  the  Cyclostomatous 
fishes  there  is  nothing  but  a  small  pouch  con- 
taining a  little  liquid  and  a  lapilliform  body. 

Much  smaller  than  the  cavities  which  con- 
tain it,  the  membraneous  labyrinth  is  sus- 
pended as  it  were  in  the  perilymph.  It  does 
not  appear  to  adhere  to  the  walls  of  the  laby- 
rinthic  cavity  except  at  the  points  where  it  re- 
ceives nervous  filaments. 

The  component  parts  of  the  membraneous 
labyrinth  are: — 

1.  The  common  sinus.  2.  The  membrane- 
ous ampullae  and  semicircular  tubes.  3.  The 
saccule. 


Fig.  238. 


A  magnified  representation  of  the  left  osseous  laby- 
rinth laid  open  to  show  the  membraneous  labyrinth 
in  its  situation.    (  From  Breschet.) 

a.  membraneous  ampulla  of  the  ampullary  sinus 
of  tlie  anterior  semicircular  canal ;  b.  membrane- 
ous ampulla  of  the  ampullary  sinus  of  the  external 
semicircular  canal ;  c.  membraneous  ampulla  of 
the  ampullary  sinus  of  the  posterior  semicircular 
canal;  d.  anterior  memhraneous  semicircular  tube; 
e.  external  membraneous  semicircular  tube ;  f. 
posterior  membraneous  semicircular  tube  :  g.  coin- 

*  De  auditu  ct  olfactu. 


mon  membraneous  tube  resulting  from  the  junction 
of  the  tubes  d  and  f ;  h.  the  place  where  the  ex- 
ternal membraneous  semicircular  tube  opens  into 
the  common  sinus  ;  i  i.  common  sinus  filling  a 
great  part  of  the  vestibule  ;  k.  a  small  mass  of 
calcareous  powder  shining  through  its  walls  ;  I  I. 
saccule,  also  containing,  m.  another  mass  of  cal- 
careous powder  ;  n  a  nervous  fasciculus,  furnishing, 
0.  an  expansion  to  the  anterior  membraneous  am- 
pulla ;  p.  another  to  the  ampulla  of  the  external 
tube,  and  q.  a  third  to  the  common  sinus  ;  r.  ner- 
vous fasciculus  to  the  saccule  ;  another  fasciculus 
of  nervous  filaments,  not  letteted,  is  seen  going  to 
the  ampulla  of  the  posterior  membraneous  semi- 
circular tube  ;  s  s.  spiral  lamina  ;  s.  the  termin- 
ation of  the  spiral  lamina  in  the  hamulus  ;  t.  com- 
mencement of  the  scala  tympani  near  the  fenestra 
rotunda,  which  is  here  no  longer  seen  ;  u.  com- 
mencement of  the  scala  vestibuli  ;  x.  extremity  of 
the  axis  around  which  the  termination  of  the  spiral 
lamina  turns  ;  y  y.  a  bristle  engaged  in  the  heli- 
cotrema  ;  x.  place  where  the  summit  of  the  axis 
is  continued  into  the  wall  of  the  osseous  labyrinth  ; 
www,  membraneous  portion  of  the  spiral  lamina, 
particularly  broad  in  the  last  turn,  (lettered  u  u  u 
in  the  figure  instead  of  w  w  w)  ;  *****  *  spaces 
between  the  walls  of  the  labyrinthic  cavity  and 
membraneous  labyrinth  occupied  by  the  peri- 
lymph. 


Fig.  239. 


The  left  membraneous  labyrinth  isolated  together  with 
the  nerves.    Magnified.    (  From  Breschet.  J 

a.  ampulla  of  the  anterior  semicircular  tube  ; 

b.  ampulla  of  the  horizontal  semicircular  tube  ; 

c.  ampulla  of  the  posterior  semicircular  tube  ;  d. 
common  tube  ;  e.  mass  of  calcareous  particles 
lying  in  the  common  sinus;  f.  the  saccule  con- 
taining also  a  mass  of  calcareous  particles ;  k. 
portio  dura  of  the  seventh  pair ;  m.  nervous  fila- 
ments to  the  ampulla  of  the  anterior  semicircular 
tube  ;  n.  filaments  to  the  ampulla  of  the  hori- 
zontal semicircular  tube;  filaments  are  also  seen 
going  to  the  ampulla  of  the  posterior  semicircular 
tube,  not  lettered  ;  o.  filaments  to  the  common 
sinus ;  q.  filaments  to  the  saccule ;  r.  cochlear 
nerve. 

The  common  sinus,  membraneous  ampulla, 
and  membraneous  semicircular  tubes. —  These 
constitute  but  one  apparatus  which  is  just  the 
counterpart  of  the  vestibule,  ampullary  sinuses, 
and  semicircular  canals  of  the  osseous  laby- 
rinth; the  semicircular  tubes  opening  into  the 
ampullae  and  common  sinus  in  the  same  way 


538 


ORGAN  OF  HEARING. 


that  the  semicircular  canals  open  into  the  am- 
pullary  dilatations  and  the  vestibule. 

The  common  sinus  is  an  elongated,  laterally 
compressed  pouch,  and  lies  in  the  posterior 
part  of  the  vestibule.  It  extends  into  the 
upper  horn  to  join  the  ampulla  of  the  superior 
vertical,  and  of  the  horizontal  semicircular 
tubes  ;  and  into  the  posterior  and  lower  horn, 
to  join  the  ampulla  of  the  posterior  semicircular 
tube,  and  to  receive  the  tubulus  communis 
and  cylindrical  extremity  of  the  horizontal 
tube,  as  they  emerge  from  their  respective 
canals.  Its  upper  end,  which  is  larger  than 
its  lower,  lies  in  the  hemi-elliptical  cavity,  to 
the  bottom  of  which  it  is  fixed  by  nervous 
filaments. 

The  membraneous  tubes  are  only  about  a 
third  part  of  the  calibre  of  the  semicircular 
canals  in  which  they  are  contained.  Like  the 
latter  they  are  distinguished  by  the  epithets, 
superior  vertical,  posterior  vertical,  and  hori- 
zontal. Each  membraneous  semicircular  tube 
opens  at  one  of  its  extremities,  like  its  cor- 
responding osseous  canal,  into  an  oval  dila- 
tation called  ampulla,  which  on  its  part  com- 
municates with  the  common  sinus.  As  the 
vertical  semicircular  canals  unite  at  one  of 
their  extremities  to  form  the  common  canal, 
so  their  corresponding  membraneous  tubes 
also  unite  to  form  a  common  tube,  tubulus 
communis,  which  occupies  the  common  canal. 

At  the  place  where  the  nervous  filaments 
enter  the  common  sinus,  its  wall  presents  a 
much  more  considerable  thickness  and  consist- 
ence than  elsewhere. 

According  to  Steifensand,*  who  has  ex- 
amined the  structure  of  the  ampullae  very 
carefully,  each  ampulla  presents  a  very  much 
arched  surface,  superficies  convexa,  and  op- 
posite to  this  a  concave  or  indented  surface, 
superficies  concava  s.  injiexa,  which  receives 
the  nervous  filaments.  Where  the  nerve  enters 
there  is  a  transverse  depression,  sulcus  trans- 
versa, by  which  this  surface  is  divided  into 
two  parts.  This  transverse  depression  on  the 
outside  produces  in  the  interior  a  fold  of  the 
membrane  composing  the  wall  of  the  ampulla, 
and  through  which  the  nerve  enters.  This 
fold  forms  a  transverse  septum,  septum  trans- 
versum,  which  divides  the  interior  of  the  am- 
pulla into  two  parts;  one  of  which,  the  sinus 
part,  communicates  by  the  osteum  sinus  with 
the  common  sinus,  and  the  other,  the  tube  part, 
by  the  osteum  tubuli  with  the  membraneous 
tube. 

Saccule,  sacculus  rotundus.  This  is  a  round 
membraneous  bag,  smaller  than  the  common 
sinus  in  front  of  which  it  lies  in  the  hemisphe- 
rical depression  of  the  vestibule.  It  is  firmly 
fixed  in  its  place  by  nervous  filaments  which 
proceed  to  it  through  the  apertures  observed 
in  the  bottom  of  the  hemispherical  depression. 
As  has  been  mentioned  in  regard  to  the  com- 
mon sinus,  the  wall  of  the  saccule  presents  an 
increase  of  thickness  and  consistence  at  the 
place  where  the  nervous  filaments  enter  it. 

*  Miiller's  Archiv.  fiir  Anat.  Physiol,  und  wis- 
senschaftl.  Medecin.  1835.  Heft.  II.  pp.  173,  174. 


Small  in  the  Mammifera,  the  saccule  is  very 
distinct  and  large  in  fishes. 

The  common  sinus  and  saccule  adhere  to 
each  other,  but  whether  their  cavities  com- 
municate has  not  been  determined.  They  are 
fixed,  as  has  been  said,  to  the  inner  wall  of  the 
vestibule,  by  the  nervous  filaments  which  they 
receive  through  the  apertures  with  which  that 
part  is  perforated.  Towards  the  outer  wall 
they  are  nowhere  in  contact  with  the  base  of 
the  stapes,  the  perilymph  intervening.  This 
circumstance,  first  distinctly  pointed  out  by 
Scarpa,*  and  particularly  insisted  on  by  Bre- 
schet,  shows  that  it  is  only  by  the  intermedium 
of  the  perilymph  that  the  movements  of  the 
stapes  can  have  any  impression  on  the  nervous 
expansions  of  the  membraneous  labyrinth. 

The  common  sinus,  ampullae,  semicircular 
tubes,  and  saccule  are  composed  of  a  firm  trans- 
parent membraneous  coat,within  which  is  a  ner- 
vous expansion,  and  outside  which  is  a  cellulo- 
vascular  layer,  in  some  places  tinged  black  or 
brown.  Of  the  nervous  expansion  we  shall 
speak  under  the  head  of  the  auditory  nerves. 
In  the  sheep,  hare,  rabbit,  &c.  the  walls  of 
the  membraneous  labyrinth  present  patches  of 
black  pigment,  a  circumstance  noticed  by 
Scarpa,!  Comparetti,J  and  Breschet.§  Before 
I  knew  of  the  observations  of  these  anatomists 
I  had  myself  observed  the  fact.  I  was  not, 
however,  led  to  the  discovery  of  it  by  accident; 
but,  being  engaged  in  researches  on  the  pig- 
ment of  the  eye,  and  considering  the  analogy 
which  the  organs  of  sense  bear  to  each  other 
in  their  general  anatomical  structure,  I  was 
curious  to  know  whether  pigment  did  not  exist 
also  in  the  ear.  Examination  proved  to  me 
that  it  did ;  for  I  found,  as  Scarpa  and  Com- 
paretti  had  previously  noticed,  pigment  de- 
posited in  the  form  of  small  black  spots  in  the 
membraneous  parts  of  the  labyrinth  in  dif- 
ferent Mammifera.  In  some  I  have  found  a 
distinct  cell ulo- vascular  layer  of  a  black  or 
brown  colour  forming  the  outer  surface  of  the 
membraneous  labyrinth.  And,  contrary  to 
what  Breschet  asserts,  I  have  found  pigment 
in  the  membraneous  labyrinth  of  the  human 
ear  also.  It  appears,  especially  on  the  am- 
pullae, under  the  form  of  a  slight  but  perfectly 
distinct  brown  tinge,  similar  to  what  is  seen 
around  the  ciliary  processes  in  the  eyes  of 
Albinos. 

Semicircular  tubes  are  found  in  all  the  Ver- 
tebrate animals,  with  the  single  exception  of 
the  Cyclostomata.  When  they  do  exist  there 
are  never  more  nor  less  than  three. 

The  common  sinus,  ampullae,  semicircular 
tubes,  and  saccule  contain  a  limpid  humour. 
Suspended  in  this  humour  there  is  found  in 
the  common  sinus  and  also  in  the  saccule  a 
small  mass  of  calcareous  powder. 

The  liquid  of  the  membraneous  labyrinth, 

*  Anatomicae  disquisitiones  de  Auditu  et  Olfactu, 
s.  xvi.  p.  55. 

t  Op.  cit.  s.  iv.  p.  49. 

i  Observat.  Anatom.  de  aure  interna  coroparat. 
p.  xxxii.  Praefat. 
§  Op.  Cit. 


ORGAN  OF  HEARING. 


539 


or  endolymph  or  vitreous  humour  (if'  the  ear. 
( Aquula  labyrinthi  membranacei.  Humor 
vitreus  auris.  Fr.  Vitrine  auditive.  Germ. 
Wasser  des  hdutigen  Labyrinths.  Die 
Glasf'euchtigkeit  des  Ohres. — This  humour, 
first  distinctly  pointed  out  by  Scarpa,  fills 
exactly  all  the  cavities  of  the  membrane- 
ous labyrinth, — that  is  to  say,  in  the  human 
ear,  the  common  sinus,  ampullae,  the  semi- 
circular tubes,  and  saccule.  Like  the  peri- 
lymph, it  is  almost  as  limpid  as  water.  In 
the  endolymph  there  are,  as  has  been  said, 
always  found  suspended  calcareous  concre- 
tions. The  endolymph  is  in  birds  as  limpid 
as  in  the  Mammifera;  but  in  reptiles  it  is  in 
general  more  dense  than  water  and  a  little 
viscid.  It  is  viscid  in  all  fishes,  but  especially 
so  in  the  Chondropterygenous,  in  which  it  often 
presents  itself  in  the  form  of  jelly.  It  is  also 
very  decidedly  viscid  in  the  Cephalopodous 
Mollusca. 

The  masses  of  calcareous  matter  contained 
within  the  membraneous  labyrinth.  — In  the  ear- 
bulb  of  all  animals  which  possess  one,  there 
are  found  small  masses  of  a  chalky  nature ; 
in  some  solid,  in  others  pulverulent.  Solid 
concretions  are  found  in  the  osseous  fishes, 
and  in  the  Chondropterygenous  fishes  with  free 
gills,  such  as  the  sturgeon.  The  chalky  mat- 
ter is  in  a  pulverulent  state  in  Mammifera, 
birds,  reptiles,  and  in  Chondropterygenous 
fishes  with  fixed  gills.  In  the  Batrachian  rep- 
tiles and  Cephalopodous  Mollusca,  the  cal- 
careous matter  appears  rather  under  a  concrete 
form. 

These  calcareous  masses  are  best  known  in 
osseous  fishes,  in  which  they  are  hard  but 
brittle  bodies  of  a  determinate  shape.  In 
those  animals,  indeed,  they  have  been  erro- 
neously considered  as  analogous  to  the  tym- 
panic ossicles  of  the  higher  V'ertebrata.  MM. 
Breschet*  and  Huschkef  have  lately  called 
particular  attention  to  the  subject,  and  have 
described  masses  of  calcareous  matter  in  the 
ear  of  reptiles,  birds,  and  Mammifera.  Scarpa 
and  Comparetti  had  observed  them  in  the 
human  ear,  without,  however,  detecting  their 
nature.  But  they  had  been  unequivocally 
noticed  before  by  De  Blainville  ;  %  and  pre- 
viously to  the  first  publication  of  Breschet's 
papers  on  the  ear  in  the  Annates  des  Sciences 
Maturelles,  I  had  also  studied  them  throughout 
the  animal  series. 

Breschet  has  proposed  for  the  solid  masses 
the  name  of  otolithi,  from  ovs,  auris,  and  AiGo?, 
lapis;  and  for  the  pulverulent  ones  that  of 
otoconia,  from  ot;;,  and  xon;,  pulvis.  Otoconia 
has  been  translated  into  German  by  Lincke  § 
Ohrsand.  Huschke  calls  the  pulverulent  matter 

*  Lib.  cit. 

t  Isis,  1834.  Heft.  1.  p.  107.  1833.  Heft.  vii. 
p.  676. 

\  De  l'Organization  des  Animauxou  Principes 
d'Anatomie  comparee,  torn.  i.  p.  451-458.  Paris, 
1822.  Also,  Cours  ile  Physiologie  generale  et  com- 
paree, &c.  Paris,  1829.  xii  Lecon.  p.  399. 

§  Das  Gehororgan,  &c.  s.  176.  p.  203.  Leipzic. 
1837.  V  h 


ear-crystals,  Ohrkrystalle.  Krause,  ear-chalk, 
Ohrkalk. 

In  the  ear  of  man  and  the  Mammifera  in 
general  there  are  two  masses  of  calcareous 
matter ;  one  in  the  common  sinus  and  the 
other  in  the  saccule.  According  to  Huschke 
and  Barruel  they  are  composed  of  mucus, 
carbonate  and  phosphate  of  lime,  and  some 
animal  matter.  They  are  said  to  be  more  dis- 
tinct in  the  foetus  than  in  the  adult.  From  my 
own  observations  I  should  say  that  they  exist 
in  the  human  adult  as  distinctly  as  in  the  fcetus. 
Concretions  are  never  found  in  the  ampulla;  or 
semicircular  canals,  either  in  man  or  any  of 
the  lower  animals. 

Examined  in  man  and  the  Mammifera  the 
concretions  are  suspended  in  the  endolymph, 
and  correspond  to  the  points  of  the  common 
sinus  and  saccule  where  the  nervous  filaments 
are  implanted. 

The  grains  composing  the  calcareous  mass 
are  held  together  by  a  soft  mucous  tissue. 

Huschke  describes  the  grains  as  crystalline, 
small  six-sided  columns,  pointed  at  the  ends 
with  three  surfaces.  They  appear  to  me,  under 
the  microscope,  to  have  an  oval  form,  more  or 
less  elongated,  in  man  and  the  mammifera, 
passing  into  a  spindle  shape  in  birds  and  rep- 
tiles, and,  though  transparent,  they  do  not  pre- 
sent any  very  decided  crystalline  form.  The 
particles  of  chalk  examined  through  the  micro- 
scope have  a  somewhat  similar  appearance,  but 
much  smaller.  The  grains  of  the  ear  are  of 
different  sizes.  Of  a  mass  which  I  removed 
from  the  ear  of  a  middle-aged  man,  the  greatest 
number  had  their  longest  diameter  equal  to  that 
of  the  globules  of  the  human  blood,  that  is, 
about  the  three-thousandth  part  of  an  inch. 

There  is  found  in  the  cochlea  of  birds  a  mass 
of  calcareous  matter.  Breschet  says  he  has 
found,  in  cochleae  of  the  human  fcetus,  which 
had  been  dried  but  not  macerated,  small  masses 
of  cretaceous  matter  deposited  near  the  summit 
of  the  cochlea;  and  Huschke*  once  found,  in 
the  fluid  of  the  cochlea  of  a  child,  a  collection 
of  microscopical  crystals. 

Cruveilhier*  asks,  do  the  small  masses  of 
cretaceous  matter,  found  in  the  ear  of  man  and 
the  mammifera,  fulfil  the  same  function  as  the 
stones  in  the  ear  of  fishes  ?  or  must  they  be 
considered  as  a  remains  only  of  a  part  import- 
ant in  other  animals  ?  Breschet  says,  "  the 
otolithes  and  otoconies  have,  for  their  use,  to 
communicate  to  the  nervous  extremities  a  more 
vivid  and  energetic  impression  than  a  simple 
liquid  like  the  endolymph  could  do;  for  the 
vibrations  of  a  solid  body  are  much  more  sen- 
sible for  their  force  and  degree  of  intensity  than 
those  of  a  liquid  body."  However  this  may  be, 
it  appears  that  the  development  of  these  con- 
cretions coincides,  in  some  degree,  with  the 
medium  inhabited  by  the  animal ;  thus,  they 
are  stony  in  most  animals  living  in  water,  and 
pulverulent  in  such  as  exist  in  air. 

The  auditory  or  acoustic  nerve. — Nervus  au- 

*  Loc.  cit. 

t  Anatomie  descriptive,  tome  iii.  p.  524. 


4 


ORGAN  OF  HEARING. 


540 

ditorius  s.  ucusticus. — Fr.  Nerf audit  if 'ou  acous- 
tique. — Germ.  Der  Gehornerv. — The  internal 
auditory  meatus  of  the  temporal  bone  appears 
to  enrl  in  a  cul-de-sac  ;  but,  examined  more 
closely,  the  bottom  is  found  divided  into  two 
unequal-sized  depressions,  an  upper  and  a 
lower,  by  a  crest,  which  extends  backwards 
from  the  anterior  and  outer  wall  of  the  meatus. 
The  upper  depression,  which  is  the  smaller,  is 
subdivided  into  two,  an  anterior  and  a  posterior, 
by  a  small  vertical  pillar.  The  anterior  leads 
into  the  aqueduct  of  Fallopius,  and  gives  pas- 
sage to  the  facial  nerve.  The  posterior  is  almost 
funnel-shaped,  and  presents  two  or  three  pretty 
large  apertures,  and  several  smaller  and  less 
distinct  ones.  These  are  the  mouths  of  small 
canals  which  lead  into  the  vestibule,  and  their 
terminating  orifices  produce  that  sieve-like  ap- 
pearance in  the  pyramidal  elevation  between 
the  hemi-elliptical  and  hemispherical  depres- 
sions, and  which  extends  towards  the  ampullary 
dilatations  in  the  superior  horn  of  the  vestibule. 

The  lower  and  larger  depression  presents  two 
subdivisions.  The  anterior  and  larger  corres- 
ponds to  the  base  of  the  axis  of  the  cochlea ; 
it  presents  a  spiral  groove  or  tract — tractus  spi- 
ralisJbraminutentus,  answering  to  the  turns  of 
the  cochlea,  and  perforated  like  a  sieve  by  nu- 
merous apertures,  which  diminish  in  size  towards 
the  centre,  where  there  is  one  opening  larger 
than  the  rest.  The  posterior  subdivision  of  the 
lower  depiession  is  a  small  superficial  fossa, 
perforated  by  two  or  three  larger,  and  a  great 
number  of  smaller  apertures,  which  open  into 
the  hemispherical  depression  of  the  vestibule, 
producing  the  sieve-like  spot  already  mentioned 
as  existing  there.  Below  this  superficial  fossa 
there  is  a  pretty  large  hole,  leading  into  a 
canal  in  the  posterior  wall  of  the  vestibule, 
which  opens  by  several  small  orifices,  forming 
the  sieve-like  spot  within  the  mouth  of  the 
ampullary  dilatation  of  the  lower  extremity  of 
the  posterior  vertical  semicircular  canal. 

The  different  minute  apertures  we  have  de- 
scribed give  passage  to  the  fibrils  of  the  audi- 
tory nerve. 

The  internal  auditory  meatus  is  lined  by 
dura  mater. 

The  facial  nerve  enters  the  internal  auditory 
meatus  along  with  the  auditory  nerve.  At  the 
bottom  of  the  meatus  there  is  a  communication 
between  the  two  nerves,  which  was  first  pointed 
out  by  Mr.  Sw?n.  Separating  from  the  audi- 
tory nerve,  the  facial  leaves  the  internal  meatus, 
by  entering  the  aqueduct  of  Fallopius. 

From  its  origin  to  about  where  it  enters  the 
internal  auditory  meatus,  the  auditory  nerve 
presents  most  distinctly  the  delicate-walled 
tubular  structure  of  brain.  Within  the  mea- 
tus it  assumes  the  ordinary  thick-walled  cylin- 
drical tubular  structure  of  nerves;  a  circum- 
stance overlooked  by  Ehrenberg,  when  he  ad- 
duced, as  a  peculiarity  of  the  special  nerves  of 
sense,  that  they  presented  throughout  their 
course  the  so-called  varicose  tubular  structure. 

The  auditory  nerve  divides  into  two  branches 
— an  anterior,  or  cochlear ;  and  a  posterior,  or 
vestibular  branch, —  which  externally  remain 


united  together  as  far  as  the  bottom  of  the 
meatus.  The  former  is  whiter,  and  has  its  fila- 
ments more  compactly  bound  together  than  the 
latter.  Examined  under  the  microscope,  the 
cylindrical  tubules  of  the  cochlear  nerve  ap- 
peared to  me  to  be  larger  than  those  of  the 
vestibular,  and  to  contain,  or  at  least  to  give  out, 
a  greater  quantity  of  nervous  medulla. 

The  anterior  branch,  or  cochlear  nerve,  ner- 
vus  cochlea,  is  something  like  a  flat  tape  rolled 
on  itself  longways.  It  proceeds  forwards  to 
that  depression  at  the  bottom  of  the  internal 
auditory  meatus,  already  described  as  corres- 
ponding to  the  base  of  the  axis.  Here  it  resolves 
itself  into  a  number  of  fine  filaments,  which 
enter  the  apertures  in  the  spiral  tract  of  holes. 
Traversing  the  small  bony  canals  leading  from 
those  apertures  into  the  substance  of  the  axis, 
they  enter  the  bony  spiral  lamina  according  as 
their  turn  comes,  by  bending  nearly  at  a  right 
angle,  and  spread  out  upon  it.  The  first  fila- 
ments given  oft'  are  the  largest,  the  rest  gradually 
diminish  in  size. 

The  first  turn  of  the  spiral  lamina  is  supplied 
by  those  which  enter  the  first  turn  of  the  spiral 
tract  of  holes  ;  the  second  turn  receives  the 
filaments  which  traverse  the  bony  canals,  into 
which  the  fine  apertures  of  the  second  turn  of 
the  spiral  tract  lead ;  and  the  last  half  turn  is 
supplied  by  that  large  bundle  of  filaments  ter- 
minating the  nerve,  and  which,  entering  the 
axis  by  the  large  opening  in  the  centre  of  the 
spiral  tract,  emerges  at  its  summit. 

The  vestibular  nerve,  nervus  vestibuli,  which 
presents  a  small  gangliform  enlargement,  di- 
vides into  three  branches.  The  uppermost, 
which  is  the  largest,  lies  in  the  depression  be- 
hind the  entrance  to  the  aqueduct  of  Fallopius. 
Its  filaments  having  penetrated  the  vestibule 
by  the  small  apertures  of  the  canals  already 
mentioned  in  the  pyramidal  elevation,  arrange 
themselves  into  three  fasciculi;  of  which  one  is 
distributed  to  the  common  sinus,  and  the  other 
two  to  the  ampulla;  belonging  to  the  superior 
vertical  and  to  the  horizontal  semicircular  tube. 

The  fibrils  of  the  next  branch  enter  the  ves- 
tibule by  the  apertures  at  the  bottom  of  the 
hemispherical  depression,  and  terminate  in  the 
saccule. 

The  third,  or  lowest  branch,  which  is  the 
smallest,  enters  that  canal  described  in  the  pos- 
terior wall  of  the  vestibule,  and  which  opens 
by  a  sieve-like  spot  within  the  ampullary  dila- 
tation of  the  posterior  semicircular  canal.  Its 
fibrils  are  distributed  to  the  ampulla  of  the 
posterior  semicircular  tube. 

Such  is  the  description  of  the  divisions  of 
the  auditory  nerve  as  given  by  most  authors, 
and  as  it  has  appeared  to  me  in  the  examina- 
tions I  have  made.  Krause  and  Breschet,  how- 
ever, describe  the  mode  of  division  ditfeiently. 
The  former  says  the  nerve  of  the  saccule  comes 
off  from  the  cochlear  nerve ;  the  latter,  that  the 
cochlear  nerve  (which  he  calls  the  posterior 
fasciculus  of  the  auditory  nerve)  gives  off  both 
the  saccular  nerve  and  the  filaments  to  the  pos- 
terior ampulla.  I  have  not  at  present  an  oppor- 
tunity to  repeat  my  examination  of  the  parts, 


ORGAN  OF  HEARING. 


541 


to  enable  me  to  say  positively  which  description 
is  the  most  correct.* 

The  nervous  fibrils  of  the  cochlea,  according 
to  Breschet,  traverse  the  osseous  zone  of  the 
spiral  lamina  under  the  form  of  cylindrical 
bundles,  which,  in  the  middle  zone,  become 
flat,  and  anastomose  by  loops.  These  loops 
are  intermingled  with  small  osseous  particles. 
Near  the  outer  margin  of  the  middle  zone,  the 
neurilemma  leaves  the  nervous  filaments,  and 
goes  to  form  the  framework  of  the  membraneous 
zone,  whilst  small  globules  are  seen  irregularly 
disseminated  around  the  convexity  of  the  loops 
which  the  filaments  form  by  their  anastomoses. 
All  this,  however,  is  not  so  unequivocally  dis- 
tinct as  Breschet  pretends.  What  I  have  been 
able  to  see  in  regard  to  the  termination  of  the 
nerves  on  the  spiral  lamina,  is  simply  this : — 
The  tubular  structure  of  the  nervous  filaments 
ceases,  among  grains  of  nervous  matter  ar- 
ranged into  a  sort  of  expansion.  There  is 
nothing  that  can  be  called  a  termination  in 
loops.  Mueller  thinks  the  nervous  fibrils  do 
not  form  loops  in  the  bird's  cochlea.  "  But," 
says  Mueller,  "  it  is  of  no  consequence,  in  the 
present  state  of  the  physiology  of  the  nerves, 
whether  the  nerves  of  sensation  form  at  their 
terminations  loops  or  not." 

Treviranusf  found  a  papillary  termination 
of  the  nervous  filaments,  not  only  in  the  retina, 
but  also  in  the  nervous  expansions  of  the  ear 
and  nose.  The  papillae  of  the  auditory  nerve 
he  saw  on  the  spiral  lamina  of  the  cochlea  in 
young  mice.  The  osseous  part  is  entirely 
covered  with  filamentous  papillae,  lying  close 
together.  Gottsche  also  found  the  ends  of  the 
nerves  of  the  cochlea  in  hares  and  rabbits  club- 
shaped.  In  the  hare,  the  nervous  cylinders  ter- 
minate in  an  oval  knob. 

The  following  figures  from  Breschet  illustrate 
his  views  of  the  mode  of  termination  of  the 
nervous  filaments  of  the  cochlea. 


Fig.  240. 


The  cochlear  nerve  entirely  isolated.    ( Magnified. ) 
a,  a,  a.  trunk  of  the  nerve  -,   6,  b,  b.  its  filaments 
in  the  osseous  zone  of  the  spiral  lamina  ;  c,  c,  c.  the 
anastomoses  in  the  middle  zone. 


*  In  the  sheep  I  have  found  the  division  of  the 
auditory  nerve  corresponding  to  the  first  description 
given  above. 

t  Beitrage,  &c.  lsten  Bandes  2tes  Heft.  Neue 
Untersuchungen  ueber  die  organischen  Elemente 
der  thierischen  Koerper,  p.  55.  Bremen,  1835. 


Fig.  24t. 


A,  a  small  piece  of  the  spiral  lamina,  natural  size, 
as  seen  from  the  surface  corresponding  to  the  scala 
vestibuli. 

B,  the  same  part  considerably  magnified  to  show 
the  globular  structure  (?)  of  the  nerves  and  the  mode 
in  which  the  neurilemma  leaves  them  at  the  place 
where  they  form  their  anastomoses. 

a.  Portion  of  the  trunk  of  the  cochlear  nerve  ; 

b.  fasciculi  lodged  in  the  osseous  zone  of  the  cochlea ; 

c,  c.  anastomoses  in  the  middle  zone  ;  d,  d,  d.  the 
neurilemma  leaving  the  nervous  loops,  interlacing 
and  forming  the  basis  of  the  membraneous  zone. 

As  to  the  mode  in  which  the  nervous  fila- 
ments enter  and  terminate  in  the  membraneous 
labyrinth.  The  nervous  filaments,  according 
to  Scarpa,  before  penetrating  the  vestibule  of 
the  small  bony  canals,  lay  aside  their  thicker 
sheath,  and  become  softer  and  whiter.  The 
filaments  expand  on  the  parts  for  which  they 
are  destined,  appear  to  form  a  network,  and, 
having  penetrated  into  the  interior,  are  resolved 
into  a  nervous  pulp  which  lines  the  inner  sur- 
face. Scarpa  compares  this  nervous  expansion 
in  the  saccule  to  the  retina. 

According  to  Breschet's  account,  the  nervous 
filaments,  in  penetrating  into  the  interior  of  the 
different  membraneous  pouches,  are  accompa- 
nied by  a  sheath  furnished  by  the  pouch  itself, 
which  is  folded  inwards,  and  accompanies  them 
until  these  filaments  spread  themselves  out. 
Hence  it  is  that,  at  the  entrance  of  the  nerves, 
the  walls  of  the  pouch  are  always  thicker,  and 
form  a  more  or  less  considerable  projection  in 
the  interior.  This  prominence  is  slight  in  the 
saccule  and  common  sinus,  but  very  well 
marked  in  the  interior  of  the  ampullae,  where  it 
forms  a  sort  of  incomplete  septum  across ;  a 
structure  which  is  small  in  man  and  the  mam- 
mifera,  but  very  much  developed  in  birds  and 
the  higher  reptiles. 

At  those  prominences  the  nervous  filaments, 
says  Breschet,  present  anastomosing  loops,  and 
the  neurilemma  leaving  them  to  be  incorporated 
with  vessels,  and  thus  to  form  the  framework 
of  the  membraneous  labyrinth,  the  nervous 
globules  come  into  immediate  contact  with  the 
mass  of  calcareous  matter. 

What  I  have  said  of  Breschet's  account  of 


542 


ORGAN  OF  HEARING. 


the  terminations  of  the  cochlear  nerve  is  also 
applicable  here.  The  filaments  of  the  nerves 
of  the  common  sinus  and  saccule  expand  in  a 
fan-like  manner  on  their  walls,  and  having  pe- 
netrated them,  are  resolved  into  a  nervous  layer 
like  the  retina,  situated  on  the  inner  surface  of 
the  walls  of  those  cavities.  This  nervous  layer 
is,  in  the  human  ear,  pervaded  by  extremely 
minute  transparent  fibres.  In  the  rabbit  I  have 
distinctly  seen,  with  a  doublet  magnifying  150 
diameters,  a  fibrous  or  tubular  structure  similar 
to  that  of  the  retina  first  discovered  by  Ehren- 
berg. 

As  regards  the  entrance  of  the  nerves  of  the 
ampullae,  Steifensand*  gives  a  similar  but  more 
detailed  account  than  Breschet,  He  says,  the 
nerve,  after  having  embraced  in  a  forked  man- 
ner about  a  third  of  the  circumference  of  the 
ampulla,  enters  the  wall  of  it. 

Resolving  itself  now  into  infinitely  fine  fila- 
ments, the  nerve  penetrates  the  septum  which 
lies  quite  close  to  the  opening  in  the  common 
sinus,  and  which  resembles  a  semilunar  emi- 
nence projecting  into  the  interior.  It  now 
covers  the  surface  of  the  septum  and  a  circum- 
scribed portion  of  the  adjacent  inner  surface  of 
the  wall  of  the  ampulla  with  an  extremely  deli- 
cate nervous  pulp.  The  two  ends  of  the  semi- 
lunar septum,  gradually  flattening  and  spread- 

Fig.  242. 


Common  sinus,  together  with  the  ampullee  and  semi  - 
circular tubes,  and  the  entrance  of  the  nerves  into 
them.    (  From  Steifensand. ) 


Fig.  243. 


The  ampullee  of  the  superior  and  horizontal  semi- 
circular tubes,  with  a  part  of  the  common  sinus.  The 
fan-like  expansion  of  the  nervous  fibrils  on  the  latter 
is  seen,  and  also  the  fork-like  expansion  of  the  nerves 
on  the  outer  surface  of  the  ampullee.  Magnified, 
(  From  Steifensand. ) 

*  Miiller's  Archiv.  fur  Anatomie,  Physiologie, 
und  wissenschaftliche  Medecin,  1835.  Heft.  ii. 
s.  174  and  184. 


ing  out,  lose  themselves  in  the  wall  of  the  am 
pulla. 

Fig.  244.  Fig.  246. 


Fig.  245.  n 


Fig.  244,  (from  Steifensand.)  The  ampulla 
opened  in  order  to  exhibit  the  septum. 

Fig.  245,  (from  Steifensand. )  The  fork-like  ter- 
mination of  the  nerve  of  the  ampulla  und  the  semilunar 
septum,  having  the  appearance  of  pure  nervous  sub- 
stance. 

Fig.  246,  ( also  from  Steifensand. J  The  expan- 
sion of  the  nervous  pulp  over  the  septum. 

Bloodvessels  of'  the  labyrinth. — The  prin- 
cipal artery  of  the  labyrinth  is  the  arteria 
auditiva  interior.  It  is  a  branch  of  the  basi- 
lar. It  enters  the  internal  auditory  meatus 
along  with  the  nerve  of  the  seventh  pair,  and 
at  the  bottom  of  it  divides  into  two  branches, 
the  cochlear  and  vestibular  arteries,  which 
enter  the  labyrinth  with  the  corresponding 
nervous  filaments. 

The  cochlear  artery,  arteria  cochlea,  divides 
into  a  number  of  branches  which  enter  the 
cochlea  by  the  spiral  tract  of  holes ;  one  in  par- 
ticular, arteria  centralis  modioli,  passes  through 
the  central  canal  of  the  axis  as  far  as  the  apex 
of  the  cochlea. 

The  vessels  of  the  walls  of  the  cochlea  are 
more  numerous  in  the  scala  vestibuli  than  in 
the  scala  tympani.  The  arterial  branches  on 
the  spiral  lamina  anastomose  with  each  other 
at  the  outer  margin  of  the  osseous  zone.  From 
the  convexity  of  the  anastomotic  arches  nume- 
rous small  arteries  arise  and  run  parallel  as  far 
as  the  outer  margin  of  the  middle  zone,  where 
they  again  anastomose,  forming  loops  infinitely 
smaller,  from  the  convexity  of  which  capillary 
vessels  run.  These  capillary  vessels  terminate 
in  a  sinus  of  a  venous  nature,  lodged  in  the 
substance  of  the  outer  margin  of  the  spiral 
lamina. 

The  vestibular  artery,  arteria  vestibuli,  sup- 
plies the  vestibule  and  semicircular  canals  to- 
gether with  their  contents,  the  saccule,  common 
sinus,  ampulla?,  and  semicircular  tubes,  and 
sends  a  branch  along  the  surface  of  the  spiral 
lamina  corresponding  to  the  vestibular  scala. 
The  stylo-mastoid  artery,  a  branch  of  the  poste- 
rior auricular,  sends  a  twig  to  the  external 
semicircular  canal.  The  occipital  artery  also 
frequently  sends  twigs  to  the  labyrinth. 

The  bloodvessels  form  a  beautiful  plexus  on 
the  ampullae,  and  considerable  trunks  run  along 
the  whole  length  of  the  semicircular  tubes,  sup- 
ported on  their  surface  by  a  delicate  cellular 
tissue,  which  forms  the  vehicle  for  the  passage 
of  the  small  lateral  branches  given  off  to  the 
walls  of  the  tubes. 


ORGAN  OF  HEARING. 


543 


Not  much  is  known  of  the  veins  of  the  laby- 
rinth. The  internal  auditory  artery  is  accom- 
panied by  a  corresponding  vein  which  carries 
away  the  blood  from  the  labyrinth,  and  empties 
it  into  the  superior  petrosal  sinus.  Another 
vein,  says  Weber,*  goes  perhaps  from  the  laby- 
rinth through  a  small  opening  in  the  cleft  of 
the  aqueduct,  and  empties  itself  into  the  trans- 
verse sinus. 

Of  the  veins  of  the  cochlea,  some,  according 
to  Breschet,  accompany  their  arteries ;  others 
enter  the  sinus,  lodged  in  the  substance  of  the 
outer  margin  of  the  spiral  lamina.  Near  the 
base  of  the  cochlea,  this  sinus  communicates 
with  the  veins  of  the  vestibule. 

Nothing  is  known  of  the  absorbents  of  the 
labyrinth. 

Fig.  247. 


A  section  of  the  cochlea  parallel  to  its  axis,  showing 
the  distribution  of  the  vessels  in  its  interior.  It  is  the 
veins  that  are  delineated,  but  their  distribution  is 
almost  the  same  as  that  of  the  arteries.  Magnified. 
( From  Breschet.) 

a,  a.  Veins  accompanying  the  trunk  of  the  coch- 
lear nerve,  and  penetrating  the  nervous  branches 
across  the  spiral  lamina  ;  b.  first  anastomoses  at  the 
periphery  of  the  osseous  zone  ;  c,  c.  second  anasto- 
moses at  the  periphery  of  the  middle  zone  ;  d.  last 
ramuscules,  which  are  almost  parallel,  occupying 
the  membraneous  zone  ;  e,  e,  e.  venous  sinus  in 
the  peripheral  margin  of  the  membraneous  zone. 

II.   Accessory  parts  of  the  apparatus 

OF  HEARING. 

Of  these  parts,  the  auricle  collects  the  so- 
norous undulations,  and  the  auditory  passage 
conducts  them  to  the  middle  ear  or  tympanum, 
where  they  are  modified  and  transmitted  to  the 
sensitive  part  of  the  apparatus,  the  ear-bulb. 

A  tympanum  is  found  in  reptiles,  birds,  and 
Mammifera,  a  perfect  external  ear  only  in  the 
Mammifera.  The  lip-like  folds  of  skin  before 
the  membrana  tympani,  in  some  birds  and  rep- 
tiles, may,  however,  be  considered  rudiments 
of  an  external  ear.  Among  the  Mammifera, 
the  Cetacea  have  no  auricle,  and  only  a  very 
contracted  auditory  passage. 

It  was  said  that  the  tympanum  exists  in  a 
greater  number  of  animals  than  the  cochlea. 
This  refers  to  a  discovery  made  by  Weber,f 
that  a  prolongation  of  the  swimming-blad- 

*  In  Hildebrandt's  Anatomie. 
t  De  Aure  et  auditu  Hominis  et  animalium, 
Lipsiae,  1820. 


der  in  the  herring,  in  the  cyprinoid  fishes, 
in  silurus  glanis,  and  in  several  species  of 
cobitis,  has  a  connexion  with  the  membraneous 
labyrinth  in  the  same  manner  that  the  prolon- 
gation of  the  mucous  membrane  of  the  throat, 
forming  essentially  the  tympanum  and  Eusta- 
chian tube,  is  extended  to  the  surface  of  the 
labyrinth ;  and  moreover,  that  in  all  those 
fishes,  with  the  exception  of  the  herring,  there 
exist  bones  analogous  to  the  tympanic  ossicles 
in  the  higher  animals. 

1.  The  middle  ear,  or  tympanum,  and  its  ap- 
pendages. 

The  cavity  of  the  typunum,  cavitus  tympani; 
Fr.  cuisse  du  tympan  ou  du  tambour ;  Germ,  die 
Trommelhohle  oder  Paukenhohle. — The  cavity 
of  the  tympanum  is  a  space  lying  at  the  peri- 
pheral surface  of  the  ear-bulb,  and  measuring 
from  above  downwards  as  well  as  from  before 
backwards  about  four-tenths  of  an  inch,  and 
from  without  inwards  about  three-twentieths  of 
an  inch.  It  is  bounded  internally  by  the  outer 
wall  of  the  osseous  labyrinth  ;  externally  by  a 
vibratile  membrane,  the  membrana  tympani, 
and  that  portion  of  the  temporal  bone  into 
,  which  it  is  framed.  Anteriorly  a  canal,  the 
['  Eustachian  tube,  leads  from  it  into  the  throat ; 
and  posteriorly  and  superiorly  it  communicates 
with  the  mastoid  cells. 

The  cavity  of  the  tympanum  is  traversed  by 
a  chain  of  small  bones,  extending  from  the 
membrana  tympani  to  the  vestibular  fenestra, 
and  is  lined  by  a  very  delicate  membrane  of  a 
fibro-mucous  character,  which  is  prolonged  into 
all  its  sinuosities  and  dependent  cavities.  This 
membrane  is  moreover  reflected  on  the  parts 
which  traverse  the  cavity,  and  envelopes  them. 
The  lining  membrane  of  the  tympanum  is  con- 
tinuous through  the  medium  of  that  of  the 
Eustachian  tube,  with  the  mucous  membrane 
of  the  throat. 

A  condition  essential  to  the  due  performance 
of  the  function  of  the  tympanum  is  that  the 
external  air  have  free  access  to  its  cavity. 

Examined  on  the  dry  bone,  the  inner  wall 
of  the  tympanum  presents  a  considerable  emi- 
nence; behind  and  below  which  is  an  opening 
somewhat  of  a  triangular  form,  and  in  a  fossa 
above  it  another  opening,  about  twice  the  size 
of  the  preceding,  and  of  an  ovoid  shape.  From 
the  description  which  has  been  already  given 
of  the  osseous  labyrinth,'  it  will  be  immediately 
perceived  that  the  eminence  in  question,  called 
the  promontory,  is  that  which  the  commence- 
ment of  the  cochlea  forms;  that  the  opening 
below  and  behind  it  is  the  fenestra  rotunda  or 
cochlear  fenestra,  and  the  opening  above  it  the 
fenestra  ovalis  or  vestibular  fenestra. 

The  surface  of  the  promontory  is  marked  by 
a  groove  ;  sometimes  instead  of  a  groove  there 
is  a  canal.  This  groove  is  continuous  below 
with  a  canal,  several  lines  in  length,  which 
opens  in  that  depression  in  the  partition  be- 
twixt the  lower  orifice  of  the  carotid  canal  and 
the  foramen  lacerum  posterius.  Above,  in  front 
of  the  vestibular  fenestra,  the  groove  again  runs 
into  a  canal  which  proceeds  forwards  and  up- 
wards between  the  canal  for  the  internal  muscle 
of  the  malleus  and  the  commencement  of  the 


544 


ORGAN  OF  HEARING. 


aqueduct  of  Fallopius,  and  opens  on  the  upper 
surface  of  the  petrous  portion  of  the  temporal 
bone  outside  and  in  front  of  the  hiatus  of  Fal- 
lopius. This  canal,  first  accurately  described 
by  Arnold,*  and  called  by  him  the  tympanic 
canal,  cana/is  tympanicus,  is  traversed  by  the 
nerve  of  Jacobson,  which  establishes  a  com- 
munication betwixt  the  glosso-pharyngeal  and 
the  otic  ganglion.  Besides  this  groove  there 
are  several  others  corresponding  to  the  branches 
of  the  tympanic  plexus  of  nerves. 

The  opening  below  and  behind  the  promon- 
tory, the  fenestra  rotunda  or  cochlear  fenestra, 
leads,  by  a  short  infundibuliform  canal  directed 
obliquely  inwards,  into  the  lower  or  tympanic 
scala  of  the  cochlea.  Looking  into  this  very 
short  canal  sideways,  a  groove  is  remarked  en- 
circling the  margin  of  its  inner  orifice.  This 
groove  receives  the  circumference  of  the  secon- 
dary membrane  of  the  tympanum. 

The  opening  above  the  promontory,  the  fe- 
nestra ovalis  or  vestibular  fenestra,  has  already 
been  described  in  speaking  of  the  vestibule. 
All  that  we  have  to  add  here  is  that  it  is  sur- 
rounded externally  close  to  its  edge  by  a  small 
channel  or  groove. 

Above  the  vestibular  fenestra  and  running  in 
much  the  same  direction  as  its  long  diameter 
is  a  round  elongated  ridge,  within  which  is  the 
aqueduct  of  Fallopius.  Below  this  ridge  and 
behind  the  vestibular  fenestra  is  a  small  mam- 
millary  or  pyramidal  eminence,  called  the  pyra- 
mid, eminentia  papillaris  s.  protuberantia  py- 
ramidalis.  The  apex  of  the  pyramid,  directed 
forwards  and  a  little  outwards,  presents  an 
opening  leading  into  a  canal,  which  extends 
backwards  and  downwards,  then  becom.ng 
vertical  lies  in  front  of  the  lower  part  of  the 
aqueduct  of  Fallopius.  In  the  thin  lamina  of 
bone  which  separates  the  two  canals  there  is 
an  aperture.  The  muscle  of  the  stapes  is 
lodged  in  the  canal,  and  its  tendon  issues  by 
the  aperture  in  the  apex,  of  the  pyramid. 
About  one-sixth  of  an  inch  behind  the  pyra- 
mid and  close  to  the  groove  for  the  insertion  of 
the  circumference  of  the  membrana  tympani 
is  the  opening  by  which  the  chorda  tympani, 
accompanied  by  an  artery,  enters  the  tym- 
panum. 

In  front  and  a  little  above  the  vestibular 
fenestra,  and  on  the  anterior  extremity  of  the 
prominence  of  the  aqueduct  of  Fallopius,  is  a 
tubular  projection  with  a  wide  open  mouth 
directed  outwards.  This  tubular  projection, 
•which  is  generally  found  incomplete  in  the 
dry  bone,  in  consequence  of  being  composed 
of  a  very  thin  brittle  substance,  is  what  has 
been  called  the  cochlear ij'orm  process.  It  is 
the  continuation,  bent  at  nearly  a  right  angle 
outwards,  of  the  canal  or  half  canal,  about  half 
an  inch  in  length,  and  destined  for  the  recep- 
tion of  the  internal  muscle  of  the  malleus, 
which  lies  above  the  osseous  part  of  the  Eusta- 
chian tube,  and  is  separated  from  it  merely  by 

*  Ueber  den  Canalis  tympanicus  und  mastoideus, 
in  Tiedemann's,  Treviranus,  und  Gmelin's  Zeit- 
schrift  fur  die  Physiologie,  B.  iv.  Heft  2,  No.  xxi. 
p.  284. 


a  thin  lamina  of  bone,  the  continuation  of 
that  forming  the  tubular  projection. 

Fig.  248. 


The  inner  wall  of  tfie  tympanum. 

a.  Promontory;  b.  vestibular  fenestra;  c.  coch- 
lear fenestra ;  d.  pyramid ;  e.  eminence  of  the 
aqueduct  of  Fallopius  ;  f.  cochleariform  process 
and  half  canal  for  the  internal  muscle  of  the  mal- 
leus. 

The  outer  wall  of  the  tympanum  is  formed 
by  the  membrana  tympani  and  the  inner  ex- 
tremity of  the  osseous  part  of  the  external  au- 
ditory passage,  in  which  the  membrana  tympani 
is  framed. 

Osseous  portion  of  the  auditory  passage. — 
This  leads  from  the  outside  of  the  temporal 
bone.  In  front  of  it  lies  the  glenoid  cavity, 
and  behind  it  is  the  mastoid  process.  It  is 
about  three-quarters  of  an  inch  long.  Its 
course  is  from  without  inwards  and  from 
behind  forwards,  at  first  a  little  upwards  and 
then  downwards.  It  is  wider  at  either  extre- 
mity than  in  its  middle.  A  cross  section  of 
the  passage  presents  an  elliptical  orifice,  the 
long  diameter  of  which  is  directed  from  behind 
forwards  and  from  below  upwards.  Its  extre- 
mities are  cut  obliquely  in  such  a  way  that  in- 
ternally the  anterior  wall  exceeds  the  posterior, 
whereas  at  the  outer  orifice  the  posterior  wall 
exceeds  the  anterior  in  length. 

The  margin  of  the  outer  orifice  is  rough  and 
irregular  to  give  attachment  to  the  cartilaginous 
portion  of  the  passage  and  to  the  auricle.  Just 
within  the  inner  orifice  the  osseous  auditory 
passage  is  grooved  all  round  except  at  its  upper 
part.  This  groove  is  for  the  reception  of  the 
circumference  of  the  membrana  tympani. 

In  the  foetus  the  osseous  portion  of  the  audi- 
tory passage  is  a  mere  ring  of  bone,  the  tym- 
panic ring,  incomplete  at  the  upper  part  where 
the  groove  in  the  adult  is  wanting.  The  tym- 
panic ring  serves  as  a  frame  for  the  membrana 
tympani.  On  the  inner  surface  of  the  superior 
extremity  of  the  anterior  cms  of  this  incomplete 
ring  of  bone  there  is  a  broad  superficial  groove, 
into  which  the  processus  gracilis  of  the  malleus 
is  received. 

By-and-bye  the  tympanic  ring  is  united  to 
the  temporal  bone,  and  in  process  of  time  the 
part  outside  the  groove  grows  outwards  so  as  to 
form  that  plate  of  bone,  thick  behind,  thin  in 
front,  rolled  together  in  the  form  of  an  incom- 
plete tube,  which  in  the  adult  composes  the 
lower,  the  anterior,  and  the  posterior  walls  of 
the  osseous  auditory  passage. 


ORGAN  OF  HEARING. 


545 


The  tympanic  ring  lies  immediately  behind 
the  glenoid  cavity  of  the  temporal  bone,  from 
which  its  anterior  part  is  separated  by  a  fissure. 
The  middle  part  of  this  fissure,  together  with  a 
line  indicating  the  whole,  remains  permanent 
in  the  adult,  and  is  known  by  the  name  of 
fissure  of  Glasser.  Its  internal  orifice  is,  in  the 
adult  as  it  is  in  the  young  bone,  in  the  outer 
wall  of  the  tympanum,  anteriorly  of,  and  close 
to  the  groove  for  the  reception  of  the  membrana 
tympani.  The  fissure  of  Glasser  gives  passage 
to  the  ligament,  or  so-called  great  external 
muscle  of  the  malleus,  which  is  inserted  into 
the  processus  gracilis  of  the  malleus.  The 
chorda  tympani  does  not  actually  pass  through 
the  fissure  of  Glasser  as  commonly  described, 
but  as  M.  Huguier*  has  shown,  through  a  par- 
ticular canal,  extremely  narrow  and  about  half 
an  inch  long,  which  runs  in  the  line  of  the 
fissure,  and  opens  at  the  re-entering  angle  be- 
tween the  squamous  and  petrous  portions  of 
the  temporal  bone. 

•  Membrane  of'  the  tympanum, ( membrana  tym- 
pani, Fr.  la  membrane,  du  tympan  ou  du  tam- 
bour,) Germ,  das  TrommetfeU  oder  Pauken- 

j'ell. — A  proper  membrana  tympani  exists  only 
in  birds  and  mammifera.  In  reptiles  there  is  a 
very  imperfect  representation  of  one.  In  birds 
the  membrana  tympani  is  convex  externally,  in 
the  mammifera,  on  the  contrary,  it  is  concave. 
The  convexity  externally  in  birds  forms  a  very 
important  distinguishing  character  of  the  class. 
In  the  cetaceous  mammifera  the  membrana  tym- 
pani is  thick,  and  presents  a  prolongation  like 
the  tube  of  a  funnel  into  the  cavity  of  the  tym- 
panum. 

The  membrana  tympani  is  situated  at  the 
bottom  of  the  external  auditory  passage,  be- 
tween which  and  the  cavity  of  the  tympanum 
it  is  interposed  like  a  partition.  It  is  a  thin, 
semi-transparent,  glistening,  dry-looking  mem- 
brane. Its  shape  is  an  oval,  truncated  at  one 
extremity,  the  upper.  Rather  more  than  the 
upper  half  of  its  vertical  diameter  is  traversed 
by  the  handle  of  the  malleus,  which,  when  the 
membrane  is  examined  on  the  living  subject  by 
means  of  the  speculum  auris,  appears  directed 
from  above  downwards  and  backwards. 

The  longest  diameter  of  the  membrana  tym- 
pani, which  is  directed  from  above  downwards, 
and  from  behind  forwards,  is  about  eight- 
twentieths  of  an  inch, and  its  shortest,  that  from 
behind  forwards,  somewhat  less  than  seven 
twentieths  of  an  inch.  It  is  fixed  by  its  cir- 
cumference in  the  circular  groove  already  men- 
tioned, at  the  inner  orifice  of  the  osseous  part 
of  the  external  auditory  passage,  or  in  the  foetus, 
the  tympanic  ring;  and  as  in  the  adult  the  ori- 
fice is  cut  obliquely  from  behind  forwards, 
from  above  downwards,  and  from  without  in- 
wards, so  is  the  direction  of  the  membrane. 
Hence  it  forms,  with  the  upper  and  posterior 
wall  of  the  auditory  passage,  an  obtuse  angle, 
and  with  the  lower  and  anterior  wall,  an  acute 
angle. 

Figure  249  represents  the  adult  membrana 

*  Cruveilhicr,  Anatomie  Descriptive,  tome  iii. 
p.  508. 

VOL.  II. 


tympani  of  the  right  side;  a.  as  seen  from  the 
auditory  passage ;  b.  as  seen  from  the  tympa- 
num. Its  shape,  size,  the  mode  in  which  the 
malleus  is  connected  with  it,  and  the  cartila- 
ginous ring  which  forms  its  circumfeience,  are 
sufficiently  well  shown. 


Fig.  249. 


The  membrana  tympani  does  not  present 
plane  surfaces.  On  the  contrary  its  centre  is 
drawn  inwards,  so  that  it  is  concave  externally, 
and  convex  internally.  This  disposition  of  the 
membrana  tympani  depends  on  its  connexion 
with  the  handle  of  the  malleus.  The  latter  being- 
fixed  in  its  whole  length  to  considerably  more 
than  the  upper  half  of  the  vertical  diameter  of 
the  former,  and  having  an  inward  direction  in- 
fenorly,  the  membrana  tympani  is,  as  it  were, 
drawn  inwards  to  it,  hence  the  concavity  ex- 
ternally. 

As  regards  the  composition  of  the  membrana 
tympani,  it  consists  of  a  proper  membrane  and 
two  borrowed  layers,  one  of  . which,  covering 
the  external  surface  of  the  proper  membrane,  is 
a  delicate  continuation,  in  the  form  of  a  blind 
end,  of  the  lining  of  the  auditory  passage,  and 
the  other,  situated  on  the  inner  surface,  is 
a  continuation  of  the  delicate  membrane  which 
gives  a  lining  generally  to  the  cavity  of  the 
tympanum.  The  latter  adheres  very  closely  to 
the  proper  membrane,  the  other  not  so  inti- 
mately, as  it  readily  separates  from  it  by  putre- 
faction, and  can  be  drawn  out  along  with  the 
rest  of  the  epidermis  of  the  external  auditory 
passage  in  a  cul-de-sac. 

Structure  of  the  proper  membrane.- — The  pro- 
per membrane  can  be  divided  into  two  layers, 
an  outer  thin  one,  consisting  of  radiating  fibres, 
and  an  inner  thicker  layer,  which  is  less  dis- 
tinctly fibrous,  though,  when  torn  it  does  indi- 
cate a  fibrous  disposition,  and  that  in  a  direc- 
tion opposite  to  the  former.  The  radiating 
fibres  run  from  its  circumference  towards  the 
centre,  to  be  fixed  to  the  handle  of  the  malleus 
along  its  whole  extent.  Towards  the  centre 
they  become  stronger,  and  being,  of  course, 
more  asrgregated,  the  layer  which  they  compose 
is  thicker  and  more  compact  in  the  centre  than 
towards  its  circumference.  The  fibres  which 
cross  the  radiating  ones  are  also  more  aggre- 
gated at  the  centre.  They  run  parallel  with 
the  handle  of  the  malleus,  and  turn  round 
its  extremity.  At  the  circumference  of  the 
proper  membrane,  there  is  a  thick  firm  ligamen- 
tous or  cartilaginous  ring,  (Jig.  249,)  which 
is  fixed  in  the  groove  of  the  bone.  This  liga- 
mentous ring  appears  to  be  formed  by  an  ag- 
gregation of  the  circular  fibres  interwoven  with 
the  peripheral  extremities  of  the  radiating 
ones.  The  part  of  the  membrana  tympani 
midway  between  its  centre  and  circumference 
is  the  thinnest. 

The  radiating  fibres  have  been  supposed  to 
2  o 


546 


ORGAN  OF  HEARING. 


be  muscular  by  Sir  Everard  Home  and  others, 
but  this  has  not  been  confirmed  by  microscopi- 
cal examination. 

Mr.  Shrapnell*  describes  at  the  anterior  and 
superior  part  of  the  membrana  tympani,  above 
the  short  process  of  the  malleus  and  its  suspen- 
sory ligament,  and  where  the  groove  in  the  bone 
is  deficient,  a  flaccid  tissue,  composed  of  irre- 
gularly arranged  fibres,  to  which  he  gives  the 
name  of  membrana  Jiuccida,  in  opposition  to  the 
re>t  of  the  membrana  tympani,  which  he  calls 
membrana  team.  This  flaccid  tissue  is  more 
developed  in  some  of  the  lower  animals,  the 
sheep  and  hare  for  instance,  than  in  man,  and 
can  be  readily  made  to  bulge  out  towards  the 
auditory  passage  by  blowing  air  into  the  Eusta- 
chian tube.  But  we  cannot  look  upon  it,  with 
Mr.  Shrapnell,  as  properly  forming  any  part  of 
the  membrana  tympani.  It  is  merely  a  mass 
of  dense,  reddish,  vascular  cellular  tissue,  sur- 
rounding the  neck  of  the  malleus,  and  conti- 
nuous with  a  similar  tissue  found  under  the 
lining  integument  of  the  upper  wall  of  the 
osseous  auditory  passage.  It  is  this  same  tis- 
sue which  has  been  described  as  a  muscle,  and 
sometimes  as  a  ligament. 

The  membrana  tympani  has  been  said  to 
present  in  the  natural  state  a  perforation  closed 
by  a  valve.  Rivinus,-f  though  not  the  first  to 
mention  it,  dwelt  on  it,  however,  in  a  parti- 
cular manner,  hence  the  perforation  has  been 
called  hiatus  Rivinianus.  The  subject  has  been 
more  recently  taken  up  by  Wittmann  and 
Vest.} 

The  membrana  tympani  receives  a  nerve 
from  the  third  division  of  the  fifth,  which  has 
communications  with  filaments  of  the  chorda 
tympani. 

To  resume  our  description  of  the  cavity  of 
the  tympanum: — In  the  upper  wall  of  the 
tympanum  there  is  an  excavation  for  receiving 
the  upper  part  of  the  incus,  and  leading  from 
that,  at  the  upper  and  back  part  of  the  tympa- 
num, is  a  short,  wide,  triangular  canal,  with  a 
rough  cellular  surface.  This  is  the  passage  to 
the  mastoid  cells,  through  the  medium  of  a 
large  cell,  sinuosiias  mastoidea  s.  sinus  mammil- 
laris,  s.  antrum  mammillare,  which  already  ex- 
ists in  the  young  bone  between  the  squamous 
and  petrous  portions. 

The  mastoid  cells  are  cavities  in  the  mas- 
toid process,  all  communicating  with  each 
other.  They  are  quite  irregular  in  regard  to 
size,  number,  and  relative  situation.  In  early 
life,  as  the  mastoid  process  is  not  fully  formed, 
they  do  not  exist,  they  are  only  found  com- 
pletely developed  in  the  adult. 

Inferiorly,  the  cavity  of  the  tympanum  forms 
a  sort  of  furrow,  which  presents  nothing  parti- 
cular. It  is  bounded  by  the  plate  of  bone 
which  forms  the  outer  wall  of  the  jugular  fossa. 

*  On  the  form  and  strueture  of  the  membrana 
tympani,  in  London  Medical  Gazette,  vol.  x.  p. 
120.    London,  1832. 

t  De  audhus  vitiis,  Lipsiae,  1717,  4,  p  32.  Tab. 
adj.  Fig.  1,  b.  et  fig.  2,  b. 

X  Ueber  die  Wittmannsche  Trommelfellklappe, 
in  den  medizinisch.  .lahrbiichern  des  oestr.  Staates. 
Bd.  v.  Wien,  1819,  p.  123,  133. 


Anteriorly,  the  cavity  of  the  tympanum 
opens  into  the  osseous  portion  of  the  Eustachian 
tube. 

The  ossicles  or  small  bones  of  the  ear  (ossi- 
cula  auditus  s.  aurium,  Fr.  osselets  de  I'  ouie  ; 
Germ.  dieG eh'6rkn'6chelchen,orG eh'urbeinchen ). 
In  the  upper  part  of  the  cavity  of  the  tympa- 
num, there  are  three  small  bones  articulated 
with  each  other,  and  forming  a  chain  which 
reaches  from  the  membrana  tympani  to  the  ves- 
tibular fenestra.  The  bones  are  named  malleus, 
incus,  and  stapes,  from  their  resembling  more  or 
less  respectively  a  hammer,  an  anvil,  and  a 
stirrup  iron. 

The  innermost  and  most  essential  is  the  sta- 
pes ;  it  is  it  alone  which  in  birds  and  reptiles 
remains,  when  the  others  have  disappeared,  or 
been  reduced  to  merely  cartilaginous  pieces. 
The  stapes  is  engaged  in  the  vestibular  fenes- 
tra. 

The  outermost  of  the  chain,  the  malleus,  is 
in  connexion  with  the  membrana  tympani. 

The  hammer  bone,  (malleus,)  Fr.  le  marteau, 
Germ,  das  Hammer,  presents  a  head,  a  neck,  a 
handle,  and  two  processes,  one  longer,  and  one 
shorter. 

The  head,  caput  s.  capitulum,  is  round  and 
smooth  on  one  surface,  and  on  the  other  pre- 
sents a  saddle-shaped  depression,  surrounded 
by  a  small  elevated  border.  The  depression 
articulates  with  the  incus,  and  the  border  is  for 
the  attachment  of  the  synovial  capsule  of  this 
minute  joint. 

The  neck,  collum  s.  cervix,  is  flattened  in  one 
diameter,  and  joins  the  handle  at  an  obtuse 
angle. 

The  handle,  manubrium  mallei,  compressed 
from  the  side  corresponding  to  the  articular 
depression  to  the  opposite  side,  and  diminish- 
ing in  thickness  towards  its  extremity,  forms, 
together  with  the  short  process,  a  double  curve, 
like  an  Italic  f.  The  extremity  is  also  com- 
pressed, as  if  beaten  flat,  but  in  an  opposite  di- 
rection, so  that  the  broad  surfaces  of  the  extre- 
mity correspond  to  the  edges  of  the  rest  of  the 
handle. 

Short  or  blunt  process,  processus  brevis  s. 
obtusus.  From  the  projecting  side  of  the  an- 
gle formed  by  the  junction  of  the  neck  and 
manubrium,  this  process,  which  is  short,  thick 
and  conical,  rises. 

The  long  or  slender  process,  processus  longus, 
s.  gracilis,  s.  spinosus,  s.  Folii,  springs  from  the 
neck,  and  from  that  side  of  it  which  corres- 
ponds with  the  non-articular  surface  of  the 
head.  The  long  process  is  of  considera- 
ble length,  and  terminates  in  a  broad,  flat, 
spatula-like  extremity,  first  described  by  Rau,* 
although  the  commencement  or  root  of  the 
process  itself  had  been  previously  delineated 
and  described  by  Folius.  The  long  process  is 
generally  found  broken  off,  either  from  its  being 
so  slender,  or  from  its  having  been,  especially 
in  old  subjects,  united  to  the  groove  in  which  it 
is  lodged. 

The  anvil  bone,  incus,  Fr.  Venclume,  Germ. 

*  Boerhaave  Praelect.  in  Tnstitt.,  Prop.  iv.  p. 
358. 


ORGAN  OF  HEARING. 


547 


der  Amboss. — This  has  been  compared,  also,  to 
a  bicuspid  molar  tooth.  It  is  divided  into  a 
body,  and  two  processes,  or  crura. 

The  body,  corpus,  presents  a  concave  articu- 
lar surface,  by  which  it  is  joined  to  the  malleus  : 
around  this  surface  is  a  groove,  (particularly 
deep  and  broad  on  the  side  towards  the  laby- 
rinth, that  is,  the  side  on  which  the  lenticular 
process  projects,)  for  the  insertion  of  the  articu- 
lar capsule. 

The  shorter  of  the  two  processes,  crus  s.  pro- 
cessus superior  s.  brevis,  is  blunt  at  its  apex, 
and  compressed  from  one  side  to  another. 

The  longer  process,  crus  s.  processus  inferior 
s.  longus,  is  more  slender,  and  becomes  gradually 
thinner  towards  its  extremity,  where  it  is  slightly 
curved,  and  where  it  presents,  supported  on  a 
short  bony  pedicle,  given  off  at  a  right  angle 
from  its  side,  the  lenticular  process,  processus 
lenticularis  incudis  ;*' — a  small  oval  plate  so 
situated,  that  a  line  drawn  through  the  long 
diameter  of  it  would  intersect  obliquely  a  line 
corresponding  to  the  long  crus  of  the  incus. 
The  free  surface  of  the  lenticular  process  is 
convex,  and  is  destined  to  articulate  with  the 
corresponding  concave  surface  on  the  head  of 
the  stapes.  The  lenticular  process  has  been, 
and  is  still,  often  described  as  a  separate  bone, 
under  the  name  of  os  lenticulare. 

The  stirrup  bone,  ( stapes ).  Fr.  Uetrier. 
Germ.  Der  Ziteigbiigel. — Exactly  like  a  stirrup, 
this  bone  presents  a  base,  two  crura,  and  a  head, 
where  the  crura  unite. 

The  base,  basis,  the  essential  part  of  the  bone, 
has  precisely  the  same  shape  as  the  vestibular 
fenestra  to  which  it  is  applied,  only  a  little 
smaller.  The  arched  margin  of  the  base  cor- 
responds to  the  upper  edge  of  the  fenestra,  and 
the  indented  margin  to  the  lower  edge. 

The  surface  of  the  base  corresponding  to  the 
vestibular  fenestra  is  slightly  convex.  The  other 
surface  is  grooved  ;  but  the  groove  is  subdivided 
by  a  ridge,  which  extends  obliquely  along  it 
lengthways,  and  which  is  continuous  at  its  ex- 
tremities with  the  upper  margin  of  the  groove 
on  the  inner  surface  of  one  crus,  and  the  lower 
margin  of  the  groove  of  the  opposite  crus. 
The  margin  of  the  base  projects  like  a  ledge 
beyond  the  insertion  of  the  crura. 

Of  the  two  crura,  one  is  shorter  and  straighter 
than  the  other ;  both  are  grooved  on  the  surfaces 
regarding  each  other,  and  the  grooves  are  con- 
tinued into  that  just  described  in  the  base,  in 
such  a  way  that  the  groove  of  one  crus  is  con- 
tinued into  one  of  the  divisions,  and  the  groove 
of  the  other  crus  into  the  other. 

The  head,  capitulum,  somewhat  oblong  and 
flat,  presents  a  superficial  depression  on  its  top, 
oblique  from  above  downwards,  and  from  with- 
out inwards,  for  receiving  the  convex  articular 
surface  of  the  lenticular  process  of  the  incus. 
There  is  sometimes  an  appearance  of  a  neck 
supporting  the  head. 

Position,  connexions,  and  articulations  of  the 
small  bones  of  the  tympanum.- — The  handle  of 

*  Blumenbach,  Geschichte,  und  Beschreibung 
der  menschl.  Knochen,  s.  50,  p.  145. 


Fig.  250. 


Small  bones  of  the  tympanum  of  the  left  side,  mag- 
nified considerably  more  than  twice.  (  f  rom  Soem- 
mering.) 

A  is  the  malleus  seen  from  the  side  correspond- 
ing to  the  membrana  tympani  :  a.  head  ;  b.  articu- 
lar surface  ;  c.  neck;  d.  handle;  e.  short  process ; 
f.  long  process. 

B.  The  incus  seen  from  its  outer  surface  also  : 
a.  body ;  b.  articular  surface  ;  c.  short  crus  ;  d. 
long  crus  ;  e  e.  lenticular  process. 

C.  The  stapes:  a.  head;  b.  neck;  c.  anterior 
and  less  bent  crus  ;  d.  posterior  and  more  bent  crus ; 
e.  base. 

D.  A  fore-shortened  view  of  the  stapes :  a.  an- 
terior and  less  curved  crus  ;  b.  posterior  crus,  the 
two  are  seen  uniting  at  the  head,  the  articular  sur- 
face of  which  is  seen;  c.  base. 

the  malleus  is  fixed  to  the  membrana  tympani. 
The  articular  surface  on  the  head  of  the  malleus, 
to  the  corresponding  surface  on  the  body  of  the 
incus,  and  the  long  process  of  the  incus,  is 
through  the  medium  of  its  lenticular  process 
articulated  with  the  stapes.  These  two  joints 
are  furnished  with  small  articular  capsules. 

The  head  of  the  malleus  lies  in  the  upper 
space  of  the  tympanum,  above  the  upper  margin 
of  the  membrana  tympani.  Its  articular  sur- 
face is  directed  obliquely  backwards  and  in- 
wards. The  surface  of  the  neck,  corresponding 
to  the  prominence  of  the  angle  which  it  forms 
with  the  manubrium,  is  hitched  like  a  shoulder 
under  the  upper  part  of  the  circumference  of 
the  inner  extremity  of  the  auditory  passage. 
The  handle  of  the  malleus,  it  has  been  said, 
is  compressed  from  one  side  to  another,  so  that 
it  presents  two  flat  surfaces  and  two  edges  or 
ridges.  That  edge  or  ridge  which  is  continued 
down  from  the  short  process  is  turned  outwards, 
and  corresponds  to  the  membrana  tympani  ; 
into  it,  indeed,  along  its  whole  extent,  the  cen- 
tral extremities  of  the  radiating  fibres  of  that 
membrane  are  inserted.  The  extremity  of  the 
handle  of  the  malleus,  which  is  curved  forwards 
and  outwards,  is  compressed,  but  in  a  direction 
contrary  to  the  rest  of  the  handle ;  so  that  one 
of  the  flat  surfaces,  that  corresponding  to  the 
outer  ridge  of  the  rest  of  the  handle,  is  con- 
nected with  the  membrana  tympani  at  a  point 
below  its  centre,  and  nearer  its  anterior  edge. 
It  is  at  this  point  that  the  bottom  of  the  con- 
cavity is  which  the  membrana  tympani  presents 
externally.  At  its  upper  part  the  membrana 
tympani  is  pushed  outwards  by  the  short  pro- 
cess of  the  malleus,  which  projects  towards  the 
auditory  passage. 

2  o  2 


548 


ORGAN  OF  HEARING. 


The  long  process  of  the  malleus  is  directed 
forwards,  and  lies  in  a  groove  within  the  anterior 
part  of  that  for  the  reception  of  the  membrana 
tympani,  and  close  to  the  fissure  of  Glasser. 

To  the  top  of  the  head  of  the  malleus,  a 
ligament  extends  downwards  from  the  upper 
wall  of  the  cavity  of  the  tympanum.  Another 
ligament,  known  also  under  the  name  of  the 
great  external  muscle  of  the  malleus,  proceeds 
from  the  spinous  process  of  the  sphenoid  bone 
backwards  and  inwards,  through  the  fissure  of 
Glasser,  and  is  inserted  into  the  long  process  of 
the  malleus.  A  third  ligament  has  been  de- 
scribed, as  arising  from  within  the  upper  and 
posterior  margin  of  the  inner  orifice  of  the 
auditory  passage  above  the  margin  of  the  niem- 
brana tympani,  and  proceeding  downwards  and 
inwards  to  be  inserted  into  the  handle  of  the 
malleus  below  the  short  process,  close  to  the 
place  where  the  connexion  between  the  handle 
of  the  malleus  and  the  membrana  tympani 
ceases.  Of  this  ligament,  which  has  also  been 
described  as  a  muscle,  small  external  muscle  of 
the  malleus,  there  is  not  much  trace,  except  in 
the  reddish  cellular  tissue  already  mentioned. 

The  body  of  the  incus  lies  in  the  upper  and 
posterior  part  of  the  tympanic  cavity.  Its 
articular  surface,  corresponding  to  that  of  the 
malleus,  is  directed  forwards,  and  a  little  up- 
wards and  outwards.  The  articulating  surfaces 
of  the  two  bones  are  incrusted  with  cartilage, 
and  the  joint  is  provided  with  a  synovial  mem- 
brane, which  is  strengthened  by  ligamentous 
fibres.  The  short  branch  is  directed  horizon- 
tally backwards  towards  the  entrance  into  the 
mastoid  cells,  and  is  there  fixed  by  means  of  a 
short  and  broad  ligament,  which  arises  from  a 
small  pit  in  the  outer  wall,  and  embracing  its 
extremity,  is  inserted  on  it.  The  long  branch 
extends  perpendicularly  downwards,  almost  pa- 
rallel with  the  handle  of  the  malleus,  but  nearer 
the  inner  wall  of  the  tympanum,  towards  which 
its  extremity,  bearing  the  lenticular  process,  is 
curved. 

The  stapes,  situated  lower  down  in  the  cavity 
of  the  tympanum  than  the  other  bones,  lies 
with  its  base  applied  to  the  vestibular  fenestra, 
to  the  circumference  of  which  it  is  closely  fixed 
by  a  circular  ligament,  ligamenhm  annulare 
buseos  stapidis.  This  ligament  springs  from  the 
margin  of  the  vestibular  fenestra,  and  is  inserted 
into  the  jutting  margin  of  the  base  of  the  stapes 
all  round.  Besides  this  ligament,  there  are  re- 
flections of  the  membrane  lining  the  tympanum, 
and  of  that  lining  the  vestibule.  The  con- 
nexions of  the  base  of  the  stapes  with  the  ves- 
tibular fenestra  are  such  as  to  admit  of  some 
degree  of  movement,  but  not  to  any  very  great 
extent, — so  little,  that  it  would  seem  one  object 
of  the  mechanism  of  the  fenestra  ovalis,  and  its 
closure  by  the  base  of  the  stapes,  was  merely 
to  interrupt  the  continuity  of  the  osseous  walls 
of  the  vestibule. 

The  short  branch  of  the  stapes  is  in  front ; 
the  long  branch  behind,  and  its  head  outwards, 
where  it  meets  and  art.culates  with  the  lenticu- 
lar process  of  the  Ion?  branch  of  the  incus. 
This  articulation  presents  also  cartilages  of  in- 


crustation, and  a  minute  synovial  capsule,  to- 
gether with  strengthening  ligamentous  fibres. 

Fig.  251. 


The  small  bones  connected  together,  and  their  relation 
to  the  osseous  labyrinth.  Left  side.  Magnified. 
(  From  Soemmerring . ) 


Muscles  of  the  small  bones. — Some  anatomists 
admit  four  muscles  :  three  attached  to  the  mal- 
leus and  one  to  the  stapes.  Of  the  three  at- 
tached to  the  malleus,two  are  described  as  having 
for  their  action  the  relaxation  of  the  membrana 
tympani;  but  these  so  called  laxutores  tym- 
pani are  merely  ligaments,  and  have  been  de- 
scribed above  as  such.  I  agree  with  Hagen- 
bach,*  Breschet,t  and  Lincke,J  that  two  muscles 
only  can  be  distinctly  demonstrated,  and  these 
two  are  both  tensors  of  the  tympanum.  A 
relaxation,  or  state  of  rest  of  the  membrana 
tympani,  takes  place  of  itself,  as  Treviranus§ 
remarks,  when  the  tensors  cease  to  act;  hence 
a  relaxator  muscle  of  the  membrana  tympani 
was  not  required 

Muscle  of  the  malleus,  musculus  interims 
mallei  s.  tensor  tympani. — This  muscle  occupies 
the  canal,  or  half  canal,  which  was  described  as 
lying  above  the  osseous  part  of  the  Eustachian 
tube.  It  arises  from  the  posterior  and  under 
part  of  the  sphenoid  bone,  from  the  superior 
part  of  the  cartilaginous  portion  of  the  Eusta- 
chian tube,  and  also  from  an  aponeurotic  sheath 
which  lines  the  canal,  or  completes  the  groove 
in  which  it  is  lodged.  Its  fibres  proceed  from 
before  backwards,  and  terminate  in  a  slender 
tendon,  which  bending  at  a  right  angle,  as  a 
rope  over  a  pulley,  enters  the  cavity  of  the 
tympanum,  through  the  tubular  projection  al- 
ready described  as  a  continuation  of  the  canal 
in  which  it  lies.  Having  entered  the  tympanum, 
it  proceeds  outwards,  and  is  inserted  into  a 
slight  elevation,  sometimes  remarked  on  the 
inner  and  anterior  surface  of  the  handle  of  the 
malleus  below  the  long  process,  and  also  a 
little  below  and  opposite  the  root  of  the  shoit 

*  Disquisitiones  anatomicae  circa  miisculos  amis 
intern*  hominis  et  Mammalium,  &c.  Basileae,  1833, 
p.  20. 

t  Op.  cit.  s.  xxxiii. 

}  Das  Ciehororgan,  &c.  Leipzig,  1837,  p.  140, 
s.  114. 

§  Biolo^ie,  Band.  vi.  p.  376. 


ORGAN  OF  HEARING. 


546 


process.  The  muscle  of  the  malleus  receives 
a  nervous  brand)  from  the  otic  ganglion. 

By  the  action  of  this  muscle,  the  handle  of 
the  malleus  is  drawn  inwards  and  forwards, 
whilst  the  head  is  moved  in  the  opposite  direc- 
tion, in  consequence  of  the  bone  moving  on  its 
long  process  as  on  an  axis.  The  result  of  this 
movement  of  the  bone  is,  that  the  membrana 
tympani,  which  is  attached  to  the  handle  of  the 
malleus  in  its  whole  length,  is  also  drawn  in- 
wards and  stretched.  Besides  the  tension  to 
which  the  membrana  tympani  is  thus  subjected, 
the  base  of  the  stapes  is  forced  against  the  ves- 
tibular fenestra,  m  consequence  of  the  move- 
ment communicated  by  the  head  of  the  malleus 
to  the  incus,  which  tends  to  press  inwards  the 
long  extremity  of  the  latter. 

Muscle  of  the  stupes,  M. stapedius. — This  is 
lodged,  and  takes  origin  in  the  cavity  of 
the  pyramid  already  described.  Much  paler 
and  smaller  than  the  preceding  muscle,  it  is 
inserted  into  the  posterior  and  upper  part  of  the 
head  of  the  stapes  by  a  slender  tendon,  which 
issues  by  the  aperture  in  the  summit  of  the  py- 
ramid, and  proceeds  downwards  and  forwards 
to  its  termination. 

The  stapedius  muscle  receives  a  nervous  fila- 
ment from  the  facial  nerve. 

The  first  effect  of  the  action  of  this  muscle 
will  be  to  press  the  posterior  part  of  the  base  of 
the  stapes  against  the  vestibular  fenestra.  At 
the  same  time  the  long  branch  of  the  incus  will 
be  drawn  backwards  and  inwards,  and  the  head 
of  the  malleus  being,  by  this  movement  of  the 
incus,  pressed  forwards  and  outwards,  its  han- 
dle will  be  carried  inwards,  and  the  membrana 
tympani  thus  put  on  the  stretch.  Breschet 
calls  the  muscle  of  the  stapes  a  iaxator,  but  I 
do  not  know  on  what  grounds. 

Magendie*  mentions  the  circumstance  that 
in  the  stapedius  muscle  of  the  ox  and  horse, 
there  is  imbedded  a  small  lenticular  bone. 
Professor  Berthold  of  Gbttingenf  has  more 
lately  called  attention  to  the  same  circumstance. 
Berthold  has  not  found  this  bone  in  man,  nor 
sheep,  nor  deer,  nor  goats,  nor  swine.  In  the 
ox  and  calf  it  is  about  one-half  to  three-fourths 
of  a  line  in  its  longest  diameter,  and  one-third 
in  the  shortest,  and  lies  surrounded  by  the  mus- 
cular and  tendinous  substance  where  the  for- 
mer passes  into  the  latter.  In  the  horse  it  is  a 
little  nearer  the  lower  margin  of  the  muscle  and 
tendon,  and  is  much  smaller  than  in  the  ox; 
moreover,  it  is  not  round,  but  is  a  longish  plate, 
somewhat  thicker  in  the  middle. 

At  the  place  where  the  stapedius  muscle  is 
inserted  into  the  stapes,  HyrtlJ  has  sometimes 
found  in  the  human  ear  a  small  process  of  bone 
which  in  some  cases  was  so  long  as  to  extend 

*  Sur  les  organes  qui  tendent  ou  relachent  la  mem- 
brane du  tympan  et  la  chaine  des  osselets  de  l'ouie 
dans  l'homme  et  les  animaux  mammiferes.  In 
Journal  de  Physiologie  experimental,  t.  1.,  p. 
346.    Paris,  1821. 

t  Ueber  ein  linsenformiges  Kndchelchen  im 
Musculus  Stapedius  mehrerer  Saugethiere.  In 
Mueller's  Archiv.  Jahrg.  1838. 

i  Beitr'age  zur  patbologischen  Anatomie  des 
Gehbrorgans,  in  the  Medicin.  Jahrb'ucher  .  des 
k.  k.  oestr.  Staates.  Wien  1836.  Bd.  xx.  p. 
439. 


into  the  belly  of  the  muscle  itself.  Teichmeyer* 
has  described  this  free  bone  of  the  stapedius 
muscle  as  constant  in  man. 

Having  described  the  walls  and  contents  of 
the  cavity  of  the  tympanum,  we  come  now  to 
speak  of  the  membrane  which  lines  it. 

The  lining  membrane  of  the  cavity  of  the 
tympanum  is  in  continuity  with  the  mucous 
membrane  of  the  throat,  through  the  Kustachian 
tube.  Extremely  delicate,  and  in  some  parts 
very  vascular,  it  is  not  merely  a  mucous 
membrane,  but  is  theoretically  a  combination 
of  periosteum  and  mucous  membrane,  being 
what  Bicbat  called  fibro-mucous.  It  invests  all 
the  elevations  and  depressions  observed  on  the 
walls  of  the  tympanum,  and  extends  into  the 
mastoid  cells.  The  outer  layer  of  the  mem- 
brane of  the  fenestra  rotunda,  membrana  tym- 
pani secundaria,  is  a  continuation  of  it. 

The  base  of  the  stapes  is  fixed  by  its  circum- 
ference to  the  outer  edge  of  the  groove,  which 
encircles  the  vestibular  fenestra,  by  a  membrane 
or  ligament.  The  lining  membrane  of  the  ves- 
tibule, continued  over  the  base  of  the  stapes 
from  within,  also  invests  the  inner  surface  of 
this  annular  ligament,  whilst  the  outer  surface 
of  it  is  covered  by  the  membrane  lining  the 
tympanum  as  it  is  reflected  on  the  stapes. 

The  membrane  lining  the  tympanum  invests 
the  small  bones  and  the  tendons  of  their  mus- 
cles where  they  run  free  in  the  cavity.  A  fold 
of  it  fills  up  the  space  bounded  by  the  crura  and 
base  of  the  stapes.  The  chorda  tympani,  also, 
in  its  passage  across  the  tympanum,  is  enve- 
loped by  it.  Lastly,  it  forms  the  inner  bor- 
rowed layer  of  the  membrana  tympani,  cover- 
ing and  adhering  closely  to  the  handle  of  the 
malleus. 

The  Eustachian  tube,  ( tuba  Eustachii,  s.  ca- 
nalis  pulatinus  tympani;  Fr.  la  trompe  d'Eus- 
tuclii ;  Germ,  die  Eustuchische  Rohre  oder  der 
Gaumengang  des  mittlcren  Ohrs.)  —  The 
Eustachian  tube  is  a  passage  of  communication 
betwixt  the  cavity  of  the  tympanum  and  the 
throat.  In  length  about  an  inch  and  a  half,  it 
is  directed  from  behind  forwards,  from  without 
inwards,  and  from  above  downwards.  Its  gut- 
tural orifice  is  wider  than  that  by  which  it  opens 
into  the  tympanum. 

Proceeding  from  the  tympanum,  its  first  part 
is  an  osseous  canal,  the  osseous  part  of  the  Eus- 
tachian tube;  the  walls  of  the  remainder  of  it 
are  composed  partly  of  cartilage,  partly  of 
fibrous  membrane,  the  cartilaginous  and  mem- 
braneous portion  of  the  Eustachian  tube. 

The  osseous  part  of  the  Eustachian  tube,  pars 
ossea  tuba  Eustachii,  begins  at  the  anterior  and 
lower  part  of  the  tympanum,  by  a  funnel-like 
orifice,  and  runs  forwards  and  inwards  on  the 
outside  of  the  carotid  canal,  and  below  that  for 
the  reception  of  the  internal  muscle  of  the  mal- 
leus. It  is  about  half  an  inch  in  length,  and 
ends  by  a  notched  and  irregular  edge  at  the  re- 
entering angle,  between  the  squamous  and 
petrous  portions  of  the  temporal  bone.  Its 
calibre  contracts  in  its  course  forwards,  and  is 
compressed  from  without  and  below  inwards 

*  Vindiciae  quorundam  inventorum  anat.  in  dubium 
vocatorum.    Heme.  1727.  4. 


550 


ORGAN  OF  HEARING. 


and  upwards.  In  the  dry  bone  it  is  wide 
enough  to  admit  the  end  of  a  quill  stripped  of 
its  feathery  part,  about  one-twelfth  of  an  inch 
thick.  In  the  recent  state,  when  lined  by  its 
mucous  membrane,  it  is  very  much  narrower. 

The  car  tilaginous  and  membraneous  portion 
of  the  Eustachian  tube, pars  curlitagineaet  mem- 
branacea  tuba  Eustac/ut. — In  the  skull  it  is  ob- 
served that  the  osseous  part  of  the  Eustachian 
tube  is  continuous  with  a  sort  of  gutter  which 
is  formed  by  the  outer  and  anterior  side  of  the 
petrous  bone,  and  the  posterior  inner  and  lower 
margin  of  the  great  wing  of  the  sphenoid  bone. 
To  this  gutter  the  external  wall  of  that  part  of 
the  Eustachian  tube  under  consideration,  which 
is  partly  cartilaginous  and  partly  fibro-membra- 
neous,  corresponds  at  its  tympanic  extremity; 
towards  the  guttural  orifice  of  the  tube,  the 
membraneous  wall  is  applied  against  the  circum- 
flex muscle  of  the  palate.  The  inner,  and  also 
the  upper  wall  of  this  portion  of  the  Eustachian 
tube,  is  formed  of  a  grooved  cartilaginous  la- 
mina of  a  triangular  form,  fixed  by  dense  cel- 
lular tissue  to  the  irregular  extremity  of  the 
osseous  portion,  to  the  apex  of  the  petrous 
bone,  and  to  the  root  of  the  inner  plate  of  the 
pterygoid  process  of  the  sphenoid.  At  the 
guttural  orifice  of  the  Eustachian  tube,  it  forms 
a  semilunar  prominence  with  its  convexity 
turned  upwards  and  backwards.  The  cartila- 
ginous plate  of  the  outer  wall  does  not  extend 
to  the  mouth  of  the  tube,  but  only  fills  up  that 
place  where  the  outer  wall  of  the  bony  groove 
above-mentioned  as  continuous  with  the  osseous 
part  of  the  Eustachian  tube  is  defective,  that  is, 
from  before  the  foramen  spinosum  of  the  sphe- 
noid to  the  scaphoid  fossa  at  the  root  of  the  in- 
ner plate  of  the  pterygoid  process. 

The  cartilaginous  and  membraneous  portion 
of  the  Eustachian  tube  is  about  one  inch  long. 
Being  compressed  from  within  outwards,  a  sec- 
tion of  it  is  an  elliptical  fissure.  From  its  junc- 
tion with  the  osseous  portion,  it  goes  on  widen- 
ing, so  that  the  point  of  junction  is  the  narrow- 
est part  of  the  tube; — in  the  recent  state,  about 
one-thirtieth  of  an  inch  in  diameter,  just  suffi- 
cient to  admit  a  small  probe. 

The  mouth  of  the  Eustachian  tube  in  the 
throat  forms  an  oval-shaped  fissure,  about 
three-eighths  of  an  inch  long,  bounded  ante- 
riorly and  posteriorly  by  prominent  swollen 
edges.  The  fissure  is  directed  obliquely  from 
above  downwards,  and  from  before  backwards, 
and  is  situated  at  the  upper  and  lateral  part  of 
the  pharynx  behind  the  soft  palate.  In  refe- 
rence to  the  nasal  passage,  my  observation 
agrees  with  that  of  Kramer,*  that  the  lower 
angle  of  the  guttural  orifice  of  the  Eustachian 
tube  lies  a  very  little  deeper  than  the  horizontal 
line  of  the  lowest  meatus,  whilst  the  upper 
angle  is  a  little  deeper  than  the  horizontal  line 
of  the  middle  meatus. 

The  Eustachian  tube  is  essentially  a  tegumen- 
tary  canal ;  through  it  atmospherical  air  is  ad- 
mitted into  the  tympanum,  a  condition  which, 
by  keeping  up  an  equable  pressure  on  either 
side  of  the  membrana  tympani,  and  giving  free 

*  Die  Erkenntniss  unci  Heilung  der  Ohrenkrank- 
heiten.    Berlin,  1836.  p.  243. 


scope  to  the  play  of  the  small  bones  upon  each 
other,  is  necessary  for  the  perfect  exercise  of 
hearing.  Its  lining  membrane  is  continuous 
with  that  of  the  throat  on  the  one  hand,  and 
with  that  of  the  tympanum  on  the  other. 
At  the  guttural  orifice  of  the  tube,  it  has  all  the 
properties  of  the  mucous  membrane  of  the 
nose  and  throat ;  as  it  approaches  the  tympa- 
num it  becomes  thinner  and  finer,  until  it 
assumes  all  the  characters  of  the  fibro-mucous 
lining  of  the  tympanum.  Within  the  osseous 
portion  of  the  tube,  it  no  longer  presents  any  of 
the  mucous  glands  which  are  found  in  the 
mucous  membrane  of  the  prominent  edges  of 
the  guttural  orifice,  and  in  that  lining  the  carti- 
laginous and  membraneous  portion — mucous 
glands,  which  perform  so  important  a  part  in 
the  economy,  and  particularly  the  morbid  states, 
of  the  Eustachian  tube  and  apparatus  of  hear- 
ing generally. 


Fig.  252. 


The  two  muscles  of  the  small  bones,  and  the  Eusta- 
chian tube.    ( From  Soemmerring.) 

a.  b.  c.  d.  Eustachian  tube  ;  e.  muscle  of  the  mal- 
leus ;  f.  the  muscle  of  the  stapes. 

2.  The  external  ear,  including  the  auditory 
passage. 

A.  The  auricle  or  the  ear,  ( auricula  s.  pin- 
na,) Fr.  pavilion  de  L'oreille;  Germ,  das  Ohr. — 
The  human  auricle,  as  is  known,  presents  on 
the  surface  directed  outwards,  prominences 
bounding  gutter-like  depressions,  which  wind 
like  a  maze  in  different  directions;  but  all  lead 
at  last  into  the  auditory  passage.  Considered 
in  a  general  way,  the  surface  directed  outwards 
is  concave.  The  surface  turned  towards  the 
side  of  the  head  is,  on  the  contrary,  generally 
speaking,  convex,  but  it  is  depressed  at  the 
places  corresponding  to  the  elevations  on  the 
outer  surface,  and  more  elevated  where  the  de- 
pressions are. 

The  hem-like  fold  of  the  edge  of  the  ear  all 
round  is  called  helix.  The  eminence  within 
the  helix  is  called  ant  helix,  and  the  gutter-like 
depression  between  the  two  is  called  the  navi- 
cular fossa.  At  its  upper  extremity  the  anthe- 
lix  divides  into  two  branches,  between  which  is 
a  triangular  depression  called fossa  innominata. 
The  lower  extremity  of  the  anthelix  runs  into 
a  projection  called  antitragus,  opposite  which, 
and  under  the  anterior  part  of  the  helix,  is  a 
broad  projecting  plate  called  tragus,  which 
lies  over  the  entrance  of  the  auditory  passage 


ORGAN  OF  HEARING. 


551 


like  a  valve.  The  posterior  margin  of  the 
tragus,  and  anterior  margin  of  the  antitragus, 
meet  inferiorly;  but  superiorly  they  are  sepa- 
rated by  a  considerable  notch.  Bounded  by 
the  anthelix,  tragus,  and  antitragus,  and  tra- 
versed horizontally  by  the  commencement  of  the 
helix,  is  a  deep  cavity,  called  concha,  at  the  an- 
terior part  of  which  is  the  auditory  passage 
leading  from  it,  as  the  pipe  from  the  mouth  of  a 
funnel.  The  lower  pendulous  part  of  the  ear  is 
called  lobule. 


The  cartilage  of  the  ear  is  covered  by  peri- 
chondrium, which  imparts  considerable  strength 
to  it.  When  the  perichondrium  is  removed  by 
dissection,  the  cartilage  is  found  to  be  very 
brittle. 


Fig.  253. 


a.  b.  c.  d.  e.  the  helix  ; 
f.g.  the  upper  and  lower 
crura  of  the  anthelix  ;  h. 
the  point  of  junction  of 
the  two  crura ;  i.  h.  the 
anthelix  ;  I.  tragus  ■,  m. 
antitragus  ;  n.  lobule  ;  o. 
navicular  fossa  p.  fossa 
innominata  ;  q  cavity  of 
the  concha  ;  r.  entrance 
of  the  auditory  passage. 


The  auricle  of  the  left  side  ( reduced  in  size ).  (  From 
Soemmerring .  ) 

Stripped  of  the  skin  which  invests  it,  the 
auricle  is  found  to  be  composed  of  a  cartila- 
ginous skeleton,  on  which  its  elasticity  depends. 
The  skeleton  presents,  with  some  modifications, 
all  the  eminences  and  depressions  we  have  de- 
scribed, except  the  lobule,  which  consists  merely 
of  a  prolonged  fold  of  skin,  between  the  layers 
of  which  is  cellular  and  adipose  tissue. 

In  the  skeleton  of  the  auricle,  the  helix  com- 
mences by  an  acute  point  in  the  excavation 
of  the  concha.  Gradually  becoming  broader 
and  more  elevated,  it  proceeds  obliquely  up- 
wards and  forwards,  then  turning  round  the 
upper  margin  of  the  ear,  contracts  in  breadth  ; 
and  about  the  middle  of  the  posterior  margin, 
its  hemlike  fold  having  ceased,  its  simple  edge 
is  continued  into  a  free  tail-like  process  of  car- 
tilage, which  is  separated  by  a  fissure  from  the 
antitragus.  On  the  anterior  part  of  the  helix 
above  the  tragus,  there  is  a  mammillary  process 
of  cartilage  which  gives  attachment  to  a  liga- 
ment. Behind  and  below  the  root  of  this 
mammillary  process,  there  is  a  small  vertical 
fissure  in  the  helix,  incisura  helicis. 

Regarding  the  anthelix  there  is  little  more  to 
be  said,  except  that  the  lower  branch  of  its 
upper  extremity  forms  a  very  prominent  crest ; 
and  that  inferiorly  the  anthelix  is  continued  into 
the  same  tail-like  process  that  the  helix  runs 
into,  and  is  also  partly  continued  into  the  anti- 
tragus. 

The  antitragus  is  a  small  plate  of  cartilage, 
forming  an  angle, directed  upwards  and  forwards. 
It  is  continuous  by  its  base  with  the  cartilage 
of  the  concha.  The  lobule  hangs  from  the 
antitragus,  and  the  tail-like  process  of  cartilage 
common  to  the  helix  and  anthelix. 

Tragus. — Between  the  helix  and  tragus  there 
is  no  connexion  by  cartilage.  The  space  is 
merely  filled  by  a  continuation  of  the  fibrous 
cellular  tissue  which  constitutes  the  upper  and 
posterior  part  of  the  cartilaginous  and  mem- 
braneous portion  of  the  auditory  passage. 


Fig.  254. 


a.  a.  a.  a.  helix  ;  b.  ant- 
helix ;  c.  two  crura  of 
anthelix  ;  d.  cavity  of  the 
concha  ;  e.  antitragus  ; 
f.  tragus  ;  g.  fissure  be- 
tween the  tragus  and 
commencement  of  carti- 
laginous portion  of  the 
.  auditory  passage,  the 
larger  fissure  of  Satito- 
rini. 


Skeleton  of  the  cartilage  of  the  external  ear  (dimi- 
nished).   (  From  Soemmerring.) 

The  skin  covering  the  cartilage  of  the  ear 
adheres  intimately  to  its  unequal  surface,  less 
so  to  ij:s  back  and  circumference.  The  lower 
part  of  the  hem-like  fold  of  the  helix  is  formed 
entirely  by  it ;  also  the  lobule,  as  has  been 
already  said.  The  skin  of  the  auricle  contains 
a  number  of  sebaceous  follicles,  particularly  in 
the  concha,  and  around  the  entrance  of  the  au- 
ditory passage. 

On  the  tragus  is  observed,  especially  in  old 
people,  a  small  tuft  of  hair,  which  has  been 
compared  to  a  goat's  beard ;  whence  the  name 
tragus,(Tgayo;,  h  ireus,)  which  the  Germans  trans- 
late Bock.  The  antitragus  they  call  Gcgenbock. 

Ligaments  of  the  ear.  Anterior  ligament, 
( ligumentum auricula  anterius ) . — This  proceeds 
from  the  root  of  the  zygomatic  process  to  the 
lower  and  anterior  part  of  the  helix,  and  to  the 
tragus. 

Posterior  ligament,  (ligumentum  auricula 
posterius ). — Extends  from  the  outer  surface  of 
the  mastoid  process  to  the  posterior  surface  of 
the  cartilage  of  the  ear,  where  the  concha  runs 
into  the  auditory  passage.  Besides  the  above 
ligaments  binding  the  ear  to  the  head,  there  are 
others  which  extend  from  one  point  of  the  car- 
tilage of  the  ear  to  another. 

Muscles  of  the  ear. — The  muscles  of  the  ear 
fall  into  two  classes :  viz.  those  which,  arising 
from  the  head,  are  inserted  into  the  ear,  and 
move  it  as  a  whole  ;  and  those  which,  extend- 
ing from  one  part  of  the  cartilage  to  another, 
are  calculated,  were  they  strong  enough,  to  pro- 
duce a  change  in  the  general  form  of  the  auricle. 

Muscles  which  move  the  ear  as  a  whole,  or  the 
extrinsic  muscles. —  The  elevator,  or  superior 
muscle  of  the  ear,  ( M.  attollens  auriculam  s. 
superior  auricula ),  is  a  broad  thin  muscle, 
composed  of  fibres  spread  out  on  the  upper  part 
of  the  side  of  the  head.  It  arises  from  the 
middle  part  of  the  epicranial  aponeuroses,  and 
also  from  the  temporal  aponeuroses  ;  thence,  to 
its  insertion  into  that  elevation  of  the  ear-carti- 
lage on  the  surface  next  the  head,  which  cor- 
responds to  the  fossa  innominata,  the  fibres  be- 
come more  aggregated,  so  that  the  muscle  is 
much  narrower,  but  thicker  inferiorly  than  su- 
periorly.   By  elevating  the  upper  part  of  the 


ORGAN  OF  HEARING. 


ear,  it  will  widen  and  straighten  the  auditory 

passage. 

The  retractor  or  posterior  muscles  of  the  ear, 
( M.  retrahentes  auriculam,  s.  posteriores  auri- 
cula.) These  ordinarily  consist  of  three  bundles, 
sometimes  only  two,  which,  taking  their  origin 
from  the  mastoid  process,  run  forwards  to  the 
cartilage  of  the  ear,  into  winch  they  are  inserted 
at  the  eminence  on  the  back  of  the  concha, 
corresponding  to  the  commencement  of  the  helix 
on  the  other  side. 

In  drawing  the  eai  backwaids,  these  muscles 
Will  dilate  and  flatten  the  concha,  and  widen 
the  entrance  to  the  auditory  passage. 

The  anterior  muscle  of  the  ear,  (  M.uttrahens 
auriculam  s.  anterior  auricula.,)  arises  from  the 
zygomatic  process,  and,  in  its  course  backwards 
to  the  ear,  gradually  contracts,  untd  it  ends  in  a 
short  tendon,  which  is  inserted  into  the  anterior 
surlace  of  the  helix,  immediately  above  the 
tragus.    It  draws  the  ear  forwards. 


Fig.  255. 


The  cartilage  of  the  left  auricle  from  behind,  and 
the  extrinsic  muscles  (  diminished ).  (  From  Soemmer- 
ing). 

a.  m.  attollens  auriculam  ;  b.  m.  anterior  auri- 
culae ;  c.  d.  two  m.  retrahentes  auriculam. 

Intrinsic  muscles  of  the  ear.- — These  muscles 
are  very  delicate  and  weak,  little  adapted  to 
produce  any  sensible  change  in  the  form  of  the 
ear.    Five  are  admitted  : — 

The  larger  muscle  of  the  helix,  ( M.  helicis 
major,)  arises  from  the  lower  and  anterior  part 
of  the  helix,  on  the  outer  and  anterior  surface 
of  which  it  ascends  for  about  three  quarters  of 
an  inch,  and  then  is  inserted  into  the  helix  above 
the  point  where  the  ear  becomes  free  from  its 
attachment  to  the  head. 

"The  smaller  muscle  of  the  helix,  ( M.  helicis 
minor.) — This  lies  farther  down  and  more  be- 
hind than  the  preceding.    It  begins  at  the  place 


where  the  helix  rises  from  the  concha,  and  is 
inserted  into  the  posterior  margin  of  the  ascend- 
ing portion  of  the  helix. 

The  muscle  of  the  tragus,  C m.  tragicus). — Of 
an  oblong  square  form,  this  muscle  covers  the 
outer  surface  of  the  tragus,  from  the  lower  part 
to  the  upper  margin  of  which  its  fibres  run. 

The  muscle  of  the  antitrugus,  (m.  antitragi- 
cus). — The  fibres  of  this  muscle  arise  from  the 
outer  surface  of  the  antitiagus,  and  are  inserted 
by  a  small  tendon  to  which  they  converge  into 
the  lower  extremity  of  the  anthehx. 


Fig.  256. 


The  intrinsic  muscles  situated  on  the  concave  side  of 
the  auricle  (diminished ).    ( From  Soemmering ). 


The  transverse  muscle  of  the  ear,  ( m.  trans- 
versa auricula,)  is  situated  on  the  back  of  the 
ear.  It  is  composed  of  fasciculi  not  very  dis- 
tinctly muscular,  which  run  from  the  dorsum  of 
the  concha  to  the  back  of  the  anthelix,  and  the 
elevation  which  corresponds  to  the  navicular 
fossa. 

Fig.  257. 


a.  transversus  mus- 
cle ;  6.  helix ;  c.  back 
of  the  concha  ;  d.  tra- 
gus; e.  fissure  of  San- 
torini. 


The  back  of  the  cartilage  of  the'  external  ear  and 
the  transversus  muscle  ( diminished ).  (  From  Soemmer- 
ing). 

B.  'The  external  auditory  passage,  (meatus  au- 
ditorius  externus  s.  porus  acuslicus;  Fr.  Le.  con- 
duit audit  if  ou  uuriculaire;  Germ.  Der  Gehor- 
gang.) — Like  the  Eustachian  tube,  the  external 
auditory  passage  is  composed  of  an  osseous 
portion,  and  a  portion  partly  cartilaginous  and 
partly  membraneous.  The  osseous  portion  has 
been  already  described  as  a  part  of  the  outer 
wall  of  the  tympanum;  the  other  portion  comes 
to  be  noticed  here  as  a  continuation  of  the  car- 
tilage of  the  auricle.  The  passage  will  then  be 
considered  as  a  whole. 

Cartilaginous  and  membraneous  portion  of 
the  external  auditory  passage,  meatus  auditoriut 
cartilugineus-membranaceus.  This  portion  of 
the  auditory  passage,  about  half  an  inch  long,  is 
formed  in  front  and  below  by  cartilage,  above 


ORGAN  OF  HEARING. 


553 


and  behind  by  dense  fibro-membraneous  cellu- 
lar tissue,  in  which  many  cerumiiious  glands  are 
imbedded. 

The  plate  of  cartilage  which  forms  the  an- 
terior and  lower  wall  of  this  portion  of  the 
auditory  passage  is  of  a  triangular  shape  with  a 
fissure  running  through  ils  base  to  near  the  apex. 
The  base  is  below;  the  apex  above.  The  base 
corresponds  to  the  anterior  surface  of  the  mas- 
toid process.  One  side  is  attached  to  the 
anterior  and  lower  part  of  the  circumference 
of  the  outer  extremity  of  the  osseous  passage, 
by  dense  and  strong  cellular  tissue.  The  other 
side  corresponds  to  the  base  of  the  tragus. 
The  apex  or  angle  formed  by  the  two  sides 
runs  into  the  upper  part  of  the  base  of  the 
tragus,  and  corresponds  to  the  root  of  the 
zygomatic  process.  The  angle  formed  by  the 
base,  and  that  side  which  is  attached  to  the 
osseous  part  of  the  passage,  is  extended  into 
a  broad  pointed  tongue,  which  is  fixed  into  the 
deep  and  rough  depression  at  the  lowest  part 
of  the  margin  of  the  orifice  of  the  osseous 
passage.  The  angle  formed  by  the  base  and 
Ihe  other  side  is  continued  into  the  concha. 

The  dense  fibrous  cellular  tissue,  which 
completes  the  passage  above  and  behind,  ex- 
tends from  the  cartilage  of  the  concha  to  the 
upper  and  posterior  part  of  the  margin  of  the 
external  orifice  of  the  osseous  part  of  the  passage. 

What  are  called  the  fissures  of  Santonni, 
incisure  Suntoriniunte,  are: — 1.  that  fissure 
extending  through  the  base  of  the  triangular 
plate  of  cartilage  to  near  its  apex  ;  and  2.  that 
between  the  outer  margin  of  the  cartilage  and 
the  base  of  the  tragus.  These  fissures  are 
closed  by  fibrous  cellular  tissue  which,  particu- 
larly over  the  second  fissure,  appeared  to  San- 
torini  to  consist  of  muscular  fibres.  These 
fibres  have,  therefore,  received  the  name  of  the 
muscle  of  the  largest  fissure,  or  the  muscle  of 
Santorini,  m.  incisure  majuris  s.  Santorini. 
IJaller  considered  their  action  to  be,  by  ap- 
proximating the  cartilaginous  pieces,  to  shorten 
the  length  of  the  passage. 

V  iewed  as  a  whole,  the  auditory  passage  is  a 
canal  of  an  oval  calibre.  It  leads  from  the 
auricle  to  the  tympanum,  from  the  cavity  of 
which  it  is  separated  by  the  interposition  of  the 
membrana  tympani.  In  front  of  it  lies  the 
joint  of  the  lower  jaw,  behind  is  the  mastoid 
process.  In  the  adult  its  length  is  about  an  inch 
and  a  quarter,  and  its  direction  is  at  first  some- 
what forwards,  then  upwards  and  backwards, 
and  lastly  downwards  and  forwards  again.  Its 
louver  wall  is  from  one-tenth  to  one-fifth  of  an 
inch  longer  than  the  upper. 

The  auditory  passage  is  lined  by  a  continua- 
tion of  the  skin  of  the  auricle.  This  skin  be- 
comes more  and  more  delicate  as  it  approaches 
the  osseous  part  of  the  passage, — extremely  so 
where  it  is  continued  on  the  outer  surface  of 
the  membrana  tympani.  The  skin  of  the  audi- 
tory passage  is  covered  with  fine  hairs,  and  in 
old  persons  close  to  the  entrance,  hairs  like 
those  on  the  tragus,  sometimes  of  considerable 
length,  are  enrooted. 

The  skin  of  the  auditory  passage  is  connected 
to  the  subjacent  cartilage  and  bone  by  rather 


dense  and  sparing  cellular  tissue.  The  epider- 
mis readily  separates  by  putrefaction,  and  may 
be  drawn  out  like  the  finger  of  a  glove,  the 
blind  end  being  the  part  which  forms  the  outer 
borrowed  layer  of  the  membrana  tympani. 

From  about  a  tenth  of  an  inch  within  the 
auditory  passage  to  about  one-fifth  of  an  inch 
from  the  membrana  tympani,  the  lining  integu- 
ment is  perforated  by  numerous  small  aper- 
tures, the  terminations  of  the  excretory  ducts  of 
the  glands  which  secrete  the  ear-wax.  These 
excretory  orifices  are  most  numerous  about  the 
middle  of  the  passage,  towards  the  termination 
of  the  cartilaginous  and  membraneous  portion. 

The  ceruminous  glands,  glandules  cerumi? 
non<e,  are  small  round  or  oval  bodies  of  a 
brownish  yellow  colour,  and  very  vascular. 
They  are  imbedded  in  the  areola;  presented  by 
the  dense  cellular  tissue  which  connects  the 
skin  of  the  auditory  passage  to  the  subjacent 
cartilage  or  bone. 

The  ear-wax,  cerumen,  is,  as  is  known,  a 
thick  orange-coloured  or  yellowish  brown  viscid 
substance,  of  an  extremely  bitter  taste,  and 
somewhat  aromatic  odour.  When  first  secreted, 
it  is  a  thin  yellowish  milky  fluid.  (See  Leru- 
men.) 

The  auditory  passage,  especially  in  the 
middle,  is  usually  covered  with  a  more  or  less 
thick  layer  of  it.  It  consists  principally  of  a 
butter-like  fat  and  albumen  in  combination  with 
a  peculiar  animal  matter;  of  a  yellow,  bitter, 
alcoholic  extractive  matter,  with  lactate  of  potass 
and  lime  and  a  watery  extractive  matter. 

In  irritation  or  diseased  states  of  the  glands, 
the  ear-wax  is  changed  in  its  properties,  and  is 
thrown  out  in  larger  quantities  than  usual,  so 
that  it  collects  and  comes  sometimes  to  fill 
completely  the  auditory  passage,  and  thus  give 
rise  to  dulness  of  hearing. 


Fig.  258. 


Horixontal  section  of  the  auditory  passage  ( dimi- 
nished ).    (  From  Soemmerriny ). 

a.  Skin  of  the  face  in  front  of  the  ear  ;  b.  lobule 
of  the  auricle  ;  c.  the  antitragus  ;  d.  the  tragus  cut ; 
e.  ai  thelix  ;  /".helix;  g.  anterior  part  of  the  osseous 
auditory  passage,  cut;  h,h.  anterior  part  of  the 
cartilaginous  portion  of  the  passage,  cut ;  i.  poste- 
rior part  of  the  cartilage  of  the  ear  ;  h.  membrana 
tympani  ;  /.  section  of  the  mastoid  process  ;  m. 
dura  mater ;  n.  skin  behind  the  ear.  It  is  seen 
continued  over  the  auricle,  and  from  that  into  the 
auditory  passage  ;  o.  first  or  greater  curve  of  the 
auditory  passage  ;  the  end  of  which  is  directed  fur- 
wards  ;  p.  the  second  or  smaller  curve,  directed 
backwards;  q.  third  and  smallest  curve  ;  at  o.  and 
p.  are  Been  the  orifices  of  the  ceruminous  glands. 


554 


ORGAN  OF  HEARING. 


Nerves  of  the  accessory  parts  of  the  apparatus 
of  hearing. 

Nerves  of  the  tympanum. — The  tympanum 
receives  nerves  from  different  sources — from 
the  fifth,  the  seventh,  eighth,  and  ninth  pairs  of 
cerebral  nerves.  Moreover,  its  nerves  have 
communication  with  the  sympathetic  system. 

The  facial  nerve  or  portio  dura  of  the  seventh 
pair  rises  from  the  brain  by  two  roots,  which 
unite  together  in  the  meatus  auditorius  inter- 
nus,  but  before  uniting,  the  smaller  root  sends 
off' a  delicate  filament,  which  forms  a  commu- 
nication, as  has  been  mentioned,  with  the  au- 
ditory nerve.  This  communication,  first  pointed 
out  by  Swan,  has  recently  been  very  fully  in- 
vestigated by  Arnold.  According  to  the  latter, 
in  the  middle  or  at  the  bottom  of  the  internal 
auditory  meatus,  one  or  several  delicate  fila- 
ments go  oft"  from  the  smaller  branch  of  the 
facial,  and  join  the  auditory  nerve.  After  this 
the  facial  nerve  enters  the  aqueduct  of  Fallo- 
pius,  and  issues  from  the  cranium  through  the 
stylo-mastoid  hole.  In  this  course  it  receives, 
at  the  place  where  it  forms  the  knee-like  bend 
into  the  aqueduct  of  Fallopius,  the  superior 
branch  of  the  Vidian  or  superficial  petrosal 
nerve,  neivus  petrosus  superficialis,  s.  major. 

The  superficial  petrosal  nerve  comes  ofF, 
along  with  the  inferior  branch  of  the  Vidian  or 
deep  petrosal  nerve,  from  the  posterior  part  of 
the  spheno-palatine  ganglion  or  ganglion  of 
Meckel.  Leaving  the  deep  petrosal  nerve  at 
the  posterior  orifice  of  the  Vidian  canal,  the 
superficial  petrosal  proceeds  upwards  through 
the  cartilaginous  substance  in  the  foramen  lace- 
rum  medium,  and  then  runs  backwards  in  the 
groove  on  the  anterior  surface  of  the  petrous 
bone  leading  to  the  hiatus  of  Fallopius. 
Having  entered  the  latter,  it  joins  the  facial 
nerve,  and  forms,  with  its  external  fasciculi,  a 
gangliform  swelling,  intumescentia  ganglifor- 
mis  nei-vi  facialis,  of  a  grayish  appearance  and 
soft  consistence. 

From  this  swelling  a  filament  arises  by  one 
or  two  roots,  and  runs  backwards  into  the  in- 
ternal auditory  passage  to  join  the  upper  por- 
tion of  the  auditory  nerve,  where  the  first  fila- 
ment joined,  and  forms  with  it  a  small  reddish 
gray  elevation,  known  to  and  delineated  by 
Scarpa. 

Another  branch,  which  arises  from  the  gan- 
glionic swelling,  is  the  chorda  tympani.  The 
chorda  tympani  thus  in  reality  derives  its  origin 
both  from  the  facial  and  the  superficial  petrosal 
nerves.  The  chorda  tympani  accompanies  the 
facial  nerve  along  the  aqueduct  of  Fallopius 
till  within  a  little  of  the  exit  of  the  latter  by  the 
stylo-mastoid  hole.  The  chorda  tympani  then 
leaves  the  facial  nerve  at  an  acute  angle,  and 
proceeds  upwards  in  a  proper  canal  in  the 
bone,  enters  the  cavity  of  the  tympanum  by  the 
opening  just  within  the  posterior  part  of  the 
groove  for  the  membrana  tympani  already  de- 
scribed. From  this  opening  it  proceeds  for- 
wards between  the  long  process  of  the  incus 
and  the  handle  of  the  malleus,  to  the  fissure  of 
Glasser,  through  the  canal  beside  which,  already 
described,  it  makes  its  exit  from  the  cavity  of 
the  tympanum.    It  then  descends  by  the  inner 


side  of  the  ascending  ramus  of  the  lower  jaw, 
and  joins  at  an  acute  angle  the  lingual  nerve. 
In  its  passage  across  the  cavity  of  the  tympa- 
num, the  chorda  tympani  anastomoses  by  one 
or  several  filaments  with  the  nerve  which  the 
fifth  pair  sends  to  the  membrana  tympani. 


Fig.  259. 


The  membrana  tympani  from  within,  and  the  course 
of  the  chorda  tympani  across  the  tympanum,  together 
with  the  connexions  of  the  malleus  and  incus  (magni- 
fied ).    (  From  Soemmerritig J. 

a.  Membrana  tympani ;  b.  handle  of  the  malleus 
and  tendon  of  the  internus  mallei  cut  near  its  in- 
sertion ;  c,  c.  the  chorda  tympani. 

To  return  to  the  facial  nerve.  It  gives  off, 
a  little  below  the  pyramid,  a  branch  to  the  sta- 
pedius muscle. 

The  pneumogastric  nerve,  in  its  passage 
through  the  base  of  the  skull,  forms  a  small 
ganglion,  from  which  springs  a  nerve  which 
goes  to  the  ear,  ramus  auricularis  nervi  vagi. 
This  nerve  is  joined  by  a  filament  from  the 
petrous  ganglion  of  the  glosso-pharyngeal ;  it 
then  runs,  according  to  Arnold,  in  a  groove  in 
the  jugular  fossa,  and  at  last  arrives  at  the 
aqueduct  of  Fallopius.  Here  it  divides  into 
three  branches,  the  smallest  of  which  runs  up- 
wards in  the  aqueduct  of  Fallopius  towards 
the  origin  of  the  facial  nerve,  and  unites  with 
it;  the  second  branch,  which  is  somewhat 
larger,  runs  downwards,  and  also  anastomoses 
with  the  facial.  The  third  and  most  considera- 
ble branch  will  be  noticed  along  with  the 
nerves  of  the  auricle  and  auditory  passage. 

The  nervous  anastomosis  in  the  tympanum. — 
The  principal  nerve  of  this  anastomosis  is  the 
nerve  of  Jacobson,  or  tympanic  nerve  of  Arnold. 

The  tympanic  nerve,  nervus  tympanicus,  ex- 
tends between  the  petrous  ganglion  of  the  glosso- 
pharyngeal nerve  and  the  otic  ganglion  or  gan- 
glion of  Arnold.  To  follow  it  from  the  glosso- 
pharyngeal, we  find  it  arises  from  the  upper 
part  of  the  petrous  ganglion,  along  with  another 
filament,  which  goes  to  communicate  with  the 
ganglion  cervicale  supremum,  and  also  with  the 
pneumogastric.  The  tympanic  nerve  enters, 
by  the  tympanic  canal  already  described,  the 
cavity  of  the  tympanum.  Here  the  nerve  ap- 
pears near  the  anterior  margin  of  the  fenestra 
rotunda,  traverses  the  groove  on  the  promon- 
tory, arrives  in  front  of  the  vestibular  fenestra, 
then  enters  the  proper  osseous  canal,  into  which 
the  groove  on  the  promontory  is  continued  su- 


ORGAN  OF  HEARING. 


555 


periorly,  and  which  opens  on  the  surface  of  the 
petrous  bone  outside,  and  in  front  of  the  hiatus 
of  Fallopius.  From  this  the  nerve  advances 
between  the  anterior  margin  of  the  petrous 
bone  and  the  posterior  angle  of  the  great  wing 
of  the  sphenoid,  between  the  internal  muscle 
of  the  malleus  and  the  superficial  petrosal 
nerve.  There  it  approaches  the  nerve  of  the 
internus  mallei,  and  proceeds  parallel  with  it, 
and  under  the  name  of  nervus  petrosus  superfi- 
citilis  minor  Arnoldi,*  goes  to  join  the  otic 
ganglion. 

Fig,  260. 


Nervous  plexus  of  the  tympanum  (from  Breschet.) 


a.  Internal  carotid  artery  ;  b.  glosso-pharyngeal 
nerve;  c.  petrous  ganglion  of  the  same  nerve; 
d.  the  principal  trunk  of  the  nervous  plexus  of  the 
tympanum  which  extends  to  join,  e.  the  otic  gang- 
lion or  ganglion  of  Arnold  ;  f.  lower  maxillary 
nerve  to  which  the  ganglion  adheres  ;  9.  filaments 
of  communication  between  the  nerve  of  Jacobson 
and  the  carotid  plexus;  /(.  carotid  plexus;  i.  fila- 
ment to  the  fenestra  rotunda,  or  cochlear  fenestra  ; 
k.  filament  to  the  vestibular  fenestra;  /.filament 
going  to  anastomose  with  the  facial  nerve;  m.  fila- 
ment running  alongside  the  Eustachian  tube ; 
n.  portio  dura  of  the  seventh  pair  ;  0.  chorda  tym- 
pani  cut ;  p.  nervous  filament  from  the  otic  gang- 
lion to  the  muscle  of  the  malleus. 

The  branches  given  off  and  the  communica- 
tions formed  by  the  tympanic  nerve  in  the  course 
described,  are  the  following.  On  entering  the 
tympanum,  the  tympanic  nerve  divides  into 
two  branches,  a  lower  and  an  upper.  The 
lower  branch  first  gives  twigs  to  the  Eustachian 
tube,  and  then  passes  out  of  the  cavity  of  the 
tympanum  into  the  carotid  canal,  through  a 

*  Bidder  (Neurologische  Beobachtungen.  Dor- 
pat,  1836,)  has  recently  discovered  a  new  nervus 
petrosus  superficialis,  which,  for  the  sake  of  distinc- 
tion, he  calls  tertius.  It  proceeds  from  the  plexus 
accompanying  the  middle  meningeal  artery  into  the 
cavity  of  the  cranium,  passes  through  a  proper  fis- 
sure in  the  anterior  surface  of  the  petrous  bone  and 
under  the  entrance  of  the  canal  of  Fallopius  into 
the  petrous  bone  to  join  the  facial.  It  is  not  always 
present. 


passage  in  the  bone,  where  it  anastomoses  with 
the  sympathetic  nerve.  The  upper  branch,  the 
continuation  of  the  nerve,  gives  a  twig  to  the 
secondary  membrana  tympani.  According  to 
Varrentrapp,  there  arises  from  it,  by  two  roots, 
a  twig  which  runs  on  the  inner  wall  of  the 
cavity  of  the  tympanum,  then  into  the  Eusta- 
chian tube,  the  cartilage  of  which  it  penetrates 
anteriorly,  and  at  last  loses  itself  in  the  mucous 
glands  around  its  guttural  orifice.  A  little 
higher  up  a  third  branch  goes  to  the  vestibular 
fenestra,  and,  according  to  Lauth,  the  tympanic 
nerve  receives,  immediately  on  its  entrance  into 
the  canal  in  the  upper  part  of  the  petrous  bone, 
a  filament  from  the  facial  nerve.  Moreover, 
the  tympanic  nerve  receives  a  filament  of  com- 
munication from  the  external  branch  of  the 
nervus  curoticus,  the  anterior  and  stronger 
branch  of  the  first  cervical  ganglion  of  the  sym- 
pathetic. 

From  the  otic  ganglion  a  nerve  goes  to  the 
internal  muscle  of  the  malleus,  ramus  ad  ten- 
sorem  tympani.  It  arises  from  the  upper  and 
posterior  part  of  the  ganglion,  and  runs  back- 
wards on  the  inner  side  of  the  middle  menin- 
geal artery  to  the  muscle. 

2.  Nerves  of  the  auricle  and  auditory  pas- 
sage.— The  auricle  and  auditory  passage  derive 
their  nerves  from  the  cervical  plexus,  from  the 
facial,  from  the  third  branch  of  the  fifth  pair, 
and  also  from  the  pneumogastric. 

The  nerve  from  the  cervical  plexus  is  the 
great  auricular  nerve,  nervus  auriculuris  mag- 
nus.  It  comes  off  from  the  anterior  branch  of 
the  third  cervical  nerve,  and  is  distributed 
principally  to  the  skin  on  the  back  of  the 
auricle  and  to  the  posterior  muscles.  One 
branch  passes  between  the  antitragus  and  the 
tail-like  process  of  the  helix  to  the  other  surface 
of  the  ear  and  ramifies  there. 

The  faciul  ner.ve  on  its  exit  from  the  stylo- 
mastoid hole  gives  off  the  posterior,  inferior  or 
deep  auricular  nerve,  nervus  auriculuris  pos- 
terior, profundus  inferior,  which  receives  a 
twig  from  the  pneumogastric  and  another  from 
the  great  auricular  branch  of  the  third  cervical 
and  then  divides  into  two  branches,  a  posterior 
larger,  and  an  anterior  smaller.  The  former 
gives  twigs  to  the  skin  of  the  mastoid  process 
and  the  retrahentes  auriculam  muscles,  the 
latter  spreads  on  the  lower  and  posterior  part 
of  the  cartilaginous  auditory  passage  and  the 
concha,  giving  twigs  to  the  skin  of  these  parts 
and  the  retrahentes  auriculam.  It  sometimes 
sends  a  branch  through  the  cartilage  into  the 
auditory  passage  to  ramify  in  the  integument 
lining  that  part. 

The  temporal  branches  of  the  facial  nerve 
send  filaments  to  the  skin  of  the  anterior  part 
of  the  auricle,  and  to  its  anterior  and  superior 
muscles. 

The  superficial  temporal  nerve,  a  branch  of 
the  posterior  and  inferior  fasciculus  of  the  third 
division  of  the  fifth  pair,  gives  off  two  branches, 
nervi  meatus  auditorii  externi,  inferior  et  supe- 
rior, the  ramifications  of  which  are  distributed 
to  the  integument  of  the  auditory  passage  and 
concha.  There  is  one  branch,  nervus  tympani, 
which  runs  under  the  upper  wall  of  the  osseous 


55C 


ORGAN  OF  HEARING. 


auditory  passage  to  the  membrana  tympani, 
between  the  layers  of  which  it  glides  and  sepa- 
rates into  very  delicate  filaments,  by  one  or  two 
of  which  it  anastomoses  with  the  chorda  tym- 
pani. The  last  branch  of  the  superficial  tem- 
poral nerve  sends  filaments  to  the  auricle  and 
its  anterior  and  superior  muscles. 

The  third  and  most  considerable  branch  of 
the  auricular  nerve  of  the  pneumogastric, 
ramus  auricular  is  nervi  vagi,  gets  into  the  cana- 
liculus mastoideus  of  Arnold,  through  an  open- 
ing near  the  lower  aperture  of  the  cunalis  chorda 
tympani.  It  heie  divides  into  two  branches, 
one  of  which  joins,  as  has  been  said,  the  pos- 
terior auricular  branch  of  the  facial  nerve ;  the 
other,  which  is  stronger,  arrives  at  the  posterior 
wall  of  the  external  auditory  passage,  gives 
filaments  to  the  ceruminous  glands,  and  in 
company  with  a  branch  of  the  posterior  auricu- 
lar artery  penetrates  the  cartikige  of  the  ear  to 
ramify  on  the  skin  covering  its  convex  surface. 

Arteries  of  the  external  ear  and  tympanum. 
The  posterior  auricular  artery.  This  sup- 
plies branches  which  ramify  on  the  convex 
surface  of  the  auricle,  and  also  turn  over  the 
helix  to  spread  out  on  the  other  surface.  Twigs 
are  also  given  off  to  the  auditory  passage. 

A  remarkable  branch  of  the  posterior  auri- 
cular is  the  stylo-mastoid  artery.  This  enters 
the  stylo-mastoid  hole  and  runs  along  the 
aqueduct  of  Fallopius,  and  ends  by  anasto- 
mosing with  a  branch  of  the  middle  meningeal, 
called  the  Vidian  artery,  which  enters  by  the 
hiatus  of  Fallopius.  In  its  course  the  stylo- 
mastoid artery  transmits  twigs  to  the  mastoid 
cells,  the  external  auditory  passage,  the  mem- 
brana tympani,  the  stapedius  muscle,  and  the 
external  semicircular  canal. 

The  twig  to  the  membrana  tympani  is  called 
arteria  tympanica  superior.  This  artery,  toge- 
ther with  the  arteria  tympanica  inferior  from 
the  internal  maxillary,  supplies  the  membrana 
tympani.  The  arteries  run  round  the  circum- 
ference of  the  membrane  and  down  along  the 
handle  of  the  malleus,  and  branching  out  form 
by  their  inosculations  a  fine  net-work. 

The  temporal  artery  sends  branches  to  the 
anterior  part  of  the  auricle,  the  external  auditory 
passage,  and  to  the  ceruminous  glands.  It  also 
gives  off'  a  branch  which  enters  the  tympanum 
by  the  fissure  of  Glasser,  and  ramifies  in  the 
mucous  membrane  of  the  outer  wall  of  that 
cavity. 

The  occipital  artery  gives  twigs  to  the  auricle. 

The  internal  ?naxillary  artery. — This  artery 
gives  off  a  branch  to  the  joint  of  the  lower  jaw, 
a  twig  of  which,  the  arteria  tympanica  inferior, 
just  mentioned,  passes  through  the  fissure  of 
Glasser  into  the  tympanum  and  inosculates  on 
the  membrana  tympani  with  the  twigs  of  the  su- 
perior tympanic  artery  of  the  stylo-mastoid.  The 
internal  maxillary  also  sends  a  branch,  the  deep 
auricular  artery,  arteria  auricularis  profunda, 
to  the  cartilaginous  portion  of  the  auditory 
passage,  where  it  supplies  the  lining  integu- 
ment and  glands.  It  moreover  sometimes  gives 
small  branches  to  the  Eustachian  tube. 

The  middle  meningeal  artery  in  the  first  part 
of  its  course  gives  branches  to  the  Eustachian 


tube.  In  the  cranium  it  sends  a  branch,  arteria 

Vidiana,  into  the  Fallopian  canal,  which  has 
been  already  described  as  anastomosing  with 
the  stylo-mastoid.  It  also  sends  branches  to 
the  tympanum,  which  ramify  in  the  mucous 
membrane  of  that  cavity  and  in  the  muscles  of 
the  small  bones. 

The  accessory  middle  meningeal  artery,  when 
present,  gives  branches  to  the  Eustachian  tube. 
The  inferior  pharyngeal  artery  also  gives 
branches  to  the  Eustachian  tube,  to  the  pyramid 
and  cavity  of  the  tympanum.  The  Eustachian 
tube  also  receives  twigs  from  the  inferior  pala- 
tine brunch  of  the  facial  artery. 

The  internal  carotid,  before  entering  the 
cranium,  sometimes  gives  a  small  twig  to  the 
Eustachian  tube  and  sends  another,  through  a 
small  passage  leading  from  the  carotid  canal 
into  the  tympanum,  to  the  promontory. 

In  some  animals,  such  as  the  mole,  the 
squirrel,  the  guinea-pig,  the  marmot,  &c.  there 
is  an  osseous  canal  like  a  bar  of  bone  extending 
over  the  vestibular  fenestra  and  running  through 
between  the  crura  of  the  stapes.  This  was 
first  observed  by  Sir  Anthony  Carlisle  in  the 
marmot  and  guinea-pig,  who  describes  it  as 
"  an  osseous  bolt  to  rivet  it  (the  stapes)  to  its 
situation."*  The  canal  is  for  the  passage  of  an 
artery  and  nerve  which  in  some  other  animals 
are  unprovided  with  an  osseous  canal  in  their 
course  through  the  stapes.  The  artery  running 
through  the  stapes  was  observed  about  ten 
years  ago  by  Professor  Ottof  in  hybernating 
animals;  but  Professor  Hyrtl  of  Prague}  has 
shewn  that  the  artery  is  by  no  means  peculiar 
to  those  animals,  as  it  does  not  occur  in  all, 
and  as  it  occurs  in  animals  which  do  not  hyber- 
nate. 

Mr.  Shrapnell  §  describes  in  the  human  ear 
an  artery  accompanied  by  a  nerve,  passing 
through  the  membrane  which  fills  up  the  space 
between  the  arms  of  the  stapes.  Mr.  Shrapnell 
was  led  to  this  observation  from  what  he  had 
seen  in  the  rat,  viz.  a  nerve  and  artery  passing 
through  the  stapes  and  supported  by  a  minute 
channel  of  bone.  Professor  Hyrtl  ||  has  more 
recently  described  three  modes  of  distribution 
of  the  arteries  in  man,  which  he  has  met  with, 
analogous  to  the  artery  running  through  the 
stapes  in  the  animals  above  mentioned. 

The  arteries  of  the  external  and  middle  ear 
are  accompanied  by  corresponding  veins.  As 
to  lymphatics,  there  are  some  small  glands 
behind  the  auricle  and  in  front  of  the  mastoid 
process.  '  The  lymphatic  vessels  of  the  external 
ear  accompany  the  arteries  and  veins,  but  prin- 
cipally the  latter.  Little  or  nothing  is  known 
of  the  lymphatics  of  the  tympanum. 

*  On  the  Physiology  of  the  Stapes  in  Philosoph. 
Trans.  1805,  p.  204. 

t  Nova  Acta  Acad.  Caes.  Leop.,  torn.  xiii. 
p.  662. 

%  Ueber  die  Analogien  der  durch  den  Steigbiigel 
verlaufenden  Arterie,  &c.  in  Medicinische  Jahr- 
biicher  des  oesterreichischen  Staates,  Bd.  xix. 
p.  457,  Wien  1836. 

S  On  the  Nerves  of  the  Ear,  in  London  Medical 
Gazette,  vol.  x.  p.  507,  1832. 

||  Loc.  cit. 


ORGAN  OF  HEARING. 


557 


III. 

1 .  Development  and  irregular  conditions  of  the 
orguyi  of  hearing. 

A.  Development  and  irregular  conditions  of 
the  ear-bulb. — Our  knowledge  of  the  early  for- 
mation of  the  ear-bulb  is  not  very  precise.  This 
much  we  know,  that  it  has  quite  a  separate 
origin  from  the  rest  of  the  apparatus  of  hearing. 
Hence,  in  the  irregular  conditions  of  the  organ 
depending  on  defective  development,  there  is 
no  constant  and  necessary  relation  betwixt  the 
labyrinth  and  the  accessory  parts  of  the  ear ; 
for  the  latter  may  be  imperfect  while  the  former 
is  in  its  natural  state,  and  vice  versa.  In  many 
cases,  however,  it  has  been  found  that  imper- 
fect development  of  the  one  attended  an  irre- 
gular condition  of  the  other.  The  earlier  a 
part  is  formed  the  fewer  deviations  it  is  subject 
to,  so  a  greater  number  of  malformations  affect 
the  accessory  parts  than  the  ear-bulb,  as  the 
former  are  developed  subsequent  to  the  latter. 

The  development  of  the  ear-bulb  commences 
very  early,  soon  after  the  appearance  of  the 
eye.  It  takes  place  by  the  springing  forth  of 
the  auditory  nerve  in  the  form  of  a  tubular 
prolongation  of  the  brain.  At  its  central  ex- 
tremity the  cavity  of  the  cerebral  prolongation 
is  continuous  with  that  of  the  fourth  ventricle. 
Its  peripheral  extremity,  which  extends  into 
the  muscular  layer  of  the  embryo,  and  particu- 
larly into  the  osseous  part  of  it,  forms  a  vesi- 
cular dilatation  which  is  gradually  separated 
from  the  brain.  To  this  vesicle  of  nervous 
substance,  which  is  the  labyrinth,  there  grows 
inwards  a  reflection  of  the  tegumentary  layer  to 
form  the  accessory  parts  of  the  organ  of  hearing. 

Such  is  Haer's  account  of  the  development 
of  the  ear  in  the  chick .  Huschke,  on  the  con- 
trary, says  that  the  membraneous  labyrinth  does 
not  arise  from  the  brain,  but  is  originally  a 
blind  sac  of  the  skin  with  an  excretory  duct, 
which  gradually  contracts,  until  the  blind  sac 
of  skin  is  completely  cut  off  from  the  rest  of 
the  tegumentary  system. 

However  this  may  be,  the  labyrinth,  accord- 
ing to  the  observations  of  Valentin*  made  on 
the  embjryo  of  the  sheep,  exists  at  a  very  early 
period,  under  the  form  of  a  simple  elongated 
tube  with  an  oblong  cavity,  which  is  the  ves- 
tibule. This  cavity  becomes  broader,  assumes 
a  rounder  form,  and  presents  in  the  interior  a 
somewhat  uneven  surface.  Soon  after  this,  its 
inner  end  is  elongated  and  begins  to  make  a 
circular  turn,  which  is  the  first  rudiment  of  the 
cochlea.  The  turns  of  this  cochlear  vesicle  be- 
come gradually  more  developed.  A  short  time 
after  the  commencement  of  the  development  of 
the  cochlea,  the  semicircular  canals  begin  to 
show  themselves  as  processes  or  diverticula  of 
the  vestibule.  There  first  appears  the  posterior 
over  and  behind  the  vestibular  fenestra;  it  be- 
comes elongated  from  within  and  below  out- 
wards and  upwards,  then  bending  in  the  form 
of  an  arch  returns  to  the  vestibule.  In  a  si- 
milar manner  the  superior  and  inferior  semi- 
circular canals  are  formed.    The  semicircular 

*  HanJhuch  der  EntwickeluDgsgeschichte  ties 
Mensehen,  p.  206. 


canals  are  at  first  proportionally  very  wide,  but 
gradually  contract,  till  at  last  the  ampullae  pre- 
sent the  only  trace  of  their  former  width.  The 
vestibule  itself  has  diminished  in  breadth  and 
length,  and  acquired  a  more  trapezoidal  form. 
The  vestibular  fenestra,  which  was  before  not 
very  distinct  and  still  round,  has  become  more 
evident  and  exhibits  an  oval  shape.  /  1 

What  Valentin  here  describes  is  only  the 
basis  of  the  future  osseous  labyrinth.  There 
exist  as  yet  no  observations  bearing  on  the  mode 
of  development  of  the  membraneous  labyrinth. 

The  irregular  conditions  which  the  labyrinth 
has  been  found  to  present,  as  well  as  the  struc- 
ture permanent  in  the  lower  animals,  corre- 
spond in  a  remarkable  manner  with  the  above-de- 
scribed stages  of  development.  Thus  in  a  mon- 
strous foetus,  Hyrtl*  found,  instead  of  a  vestibule, 
cochlea,  semicircular  canals,  and  internal  mea- 
tus, a  single  very  capacious  cavity,  containing  a 
membraneous  sac,  in  which  the  auditory  nerve, 
sufficiently  well  developed,  terminated.  There 
was  no  trace  of  vestibular  or  cochlear  fenestra, 
and  the  accessory  parts  of  the  organ  were  en- 
tirely wanting,  llodererf  describes  a  somewhat 
similar  case,  in  which,  however,  some  of  the 
accessory  parts  presented  themselves,  though 
in  a  very  rudimentary  and  imperfect  form. 

The  cochlea  has  presented  itself  as  a  mere 
subdivision  of  the  vestibule  without  any  wind- 
ings, a  state  of  parts  which  is  permanent  in 
birds.  In  other  cases,  though  presenting  wind- 
ings, these  have  been  found  fewer  than  natural, 
and  sometimes  the  spiral  lamina  has  been 
wanting  or  not  extending  throughout  all  the 
turns  of  the  cochlea,  so  that  no  subdivision 
into  scalae  or  but  a  very  imperfect  one  pre- 
sented itself.  The  semicircular  canals  are 
sometimes  smaller  and  narrower  than  usual ; 
one  or  all  of  them  have  been  found  wanting  or 
but  partially  present.  In  the  latter  case,  after 
running  a  short  way,  they  have  been  observed 
stopping  short  and  terminating  in  a  cul-de-sac. 
The  semicircular  canals,  as  they  are  formed 
later,  more  frequently  present  deviations  from 
the  regular  structure  than  the  vestibule  and 
cochlea. 

Our  knowledge  of  the  ear-bulb  in  the  human 
embryo  commences  at  about  the  third  month, 
when  the  membraneous  labyrinth  is  already 
very  perfectly  developed  and  surrounded  by  a 
cartilaginous  shell,  having  a  structure  as  com- 
plicated as  at  a  more  advanced  period  the  bony 
shell  presents.  The  membraneous  labyrinth  is 
at  this  early  period  so  firm  that  it  is  not  very 
difficult,  by  means  of  careful  dissection  and 
manipulation,  to  extract  the  whole  from  its 
cartilaginous  case. 

According  to  Meckel,}  the  membraneous  la- 
byrinth is  composed  at  first  of  two  perfectly 

*  Beitr'age  zur  pathologischen  Anatomic  des 
Gehbrorgans.  In  the  Medicinische  Jahrbucher, 
des  k.  k.  oestr.  Staates.  Wien,  1836.  Bd.  xx. 
p.  446. 

t  Descriptio  foetus  parasitici.  In  Commentariis 
Soc.  reg.  Gcettingensis.  torn.  iv.  1754,  pp.  136 — 
148. 

J  Manuel  d'Anatomie,  etc.  traduit  par  Jourdan 
et  Breschet,  tome  iii.  s.  1948— 3o  Paiis,  1825. 


558 


ORGAN  OF  HEARING. 


distinct  membranes,  the  one  simply  inclosed 
within  the  other,  but  not  connected  further. 
The  inner  membrane  is  thinner  but  firmer  and 
more  elastic  than  the  outer.  The  latter,  which 
does  not  adhere  to  the  cartilaginous  case  any 
more  than  it  does  to  the  osseous  labyrinth 
which  succeeds  it,  gradually  becomes  thin, 
until  at  the  seventh  month  there  is  no  longer 
any  trace  of  it.  The  inner  membrane,  on  the  con- 
trary, becomes  proportionally  thicker  and  firmer. 

Meckel  has  never  found  the  membraneous 
labyrinth  in  a  more  simple  form,  nor  has  he 
been  able  to  determine  whether  it  ever  exists 
naked  in  the  cranium. 

At  a  very  early  period  the  pulpy  mass  of 
the  auditory  nerve  becomes  converted  into 
nervous  bundles,  and  grows  either  by  lateral 
additions  or  by  an  increase  of  its  filaments. 
The  cochlear  part  of  it,  according  to  Valentin,* 
lies  free  in  the  tube  of  the  cochlea  under  the 
form  of  a  thick  white  cord;  it  follows  the  turns 
of  the  cochlea,  but  gives  no  considerable  la- 
teral fibrils  to  the  walls  of  it.  As  to  how  the 
auditory  nerve  ends  in  the  membraneous  laby- 
rinth at  this  period  nothing  is  known. 

In  an  anencephalous  foetus  described  by 
Hyrtl,f  the  cochlea  was  represented  by  a  ca- 
vity, from  the  base  of  which,  corresponding  to 
the  internal  meatus,  there  rose  a  pyramid  com- 
posed of  canals  and  extended  to  the  roof  of  it. 
This  pyramid  and  the  canals  composing  it  were 
the  representative  of  the  axis  and  its  canals  for 
the  transmission  of  the  fibrils  of  the  cochlear 
nerve.  There  was  no  trace  of  a  turn  of  the 
cochlea  nor  of  a  lamina  spiralis. 

We  now  enter  into  a  more  explored  region, 
viz.  the  progress  of  ossification  in  the  laby- 
rinthic  shell,  and  for  the  knowledge  we  possess 
on  the  subject  we  are  chiefly  indebted  to  the 
late  J.  F.  Meckel.}, 

The  osseous  labyrinth  is  at  first  merely  mem- 
braneous; by-and-bye  it  becomes  cartilaginous, 
and  lastly  ossifies.  The  membraneous  laby- 
rinth has  not  been  properly  distinguished  from 
it.  The  former  at  first  lies  free  in  the  cavity 
of  the  cranium ;  the  latter  has  never  been  ob- 
served in  an  uncovered  state. 

The  development  of  the  osseous  labyrinth  is 
quite  distinct  from  the  formation  of  the  bony 
substance  of  the  petrous  bone.  The  latter  com- 
mences before  the  former. 

Ossification  commences  in  the  labyrinth  to- 
wards the  end  of  the  third  month  round  the 
fenestra  rotunda,  first  at  the  upper  part,  then 
at  the  lower  part ;  and  when  a  ring  of  bone  has 
thus  been  produced,  ossification  extends  for- 
wards. At  the  same  time  that  the  process  just 
described  takes  place,  another  osseous  nucleus, 
quite  distinct  from  the  preceding,  is  developed 
at  the  outer  extremity  of  the  superior  vertical 
semicircular  canal ;  there  then  appears  a  third 
small  scale  nearly  in  the  middle  of  the  posterior 
vertical  semicircular  canal.  Proceeding  from 
the  first  nucleus  of  bone,  ossification  makes 
rapid   progress  backwards  and  downwards ; 

*  Op.  cit.  p.  208. 
t  Op.  et  loc.  cit. 
t  Op.  et  loc.  cit. 


whence  the  floor  of  the  labyrinth  is  formed' 
The  second  nucleus  enlarges  perhaps  even 
more  quickly  than  the  first,  so  that  the  whole 
superior  vertical  semicircular  canal  is  soon  os- 
sified, with  the  exception  of  its  lower  concave 
surface.  From  the  inner  extremity  of  this  se- 
micircular canal  ossification  extends  on  the 
inner  surface  of  the  petrous  bone,  circum- 
scribes the  internal  auditory  meatus,  penetrates 
into  its  interior,  and  forms  the  base  of  the 
cochlea.  In  the  fifth  month  ossification  ex- 
tends from  the  two  first  nuclei  to  the  horizontal 
semicircular  canal. 

In  the  ossification  of  the  cochlea,  that  of  the 
petrous  bone  has  but  a  very  small  share.  All 
that  the  petrous  bone  contributes  is  merely  a 
thin  prolongation  which  it  sends  between  the 
turns  of  the  cochlea.  This  process  is  at  first 
broader  than  at  a  subsequent  period.  From 
the  third  month,  as  the  cochlea  widens  from 
without  inwards,  the  process  in  question  be- 
comes thinner,  and,  at  the  same  time,  are  deve- 
loped the  less  considerable  projections  which 
separate  externally  the  first  external  turn  and  a 
half  of  the  cochlea  from  each  other. 

The  ossification  of  the  labyrinth  has  been 
found  imperfect;  thus  Krombholz*  relates  a 
case  in  which  he  found  the  semicircular  canals, 
as  well  as  both  scala;  of  the  cochlea,  presenting 
the  same  thinness  of  walls  as  is  remarked  in  the 
foetus.  Some  places  were  merely  membraneous. 
I  have  already  mentioned  that  the  aqueducts 
are  sometimes  unusually  wide,  a  circumstance 
conceivable  when  we  consider  the  mode  in 
which  most  likely  they  are  developed,  and 
which  was  spoken  of  when  considering  them. 
In  certain  of  the  lower  animals,  such  as  the 
pig,  they  are  naturally  wide. 

At  first  the  osseous  labyrinth  is  quite  dis- 
tinct from  the  mass  of  the  petrous  bone,  in 
which  it  is,  as  it  were,  embedded.  Its  outer 
surface  is,  up  to  the  fifth  month,  quite  smooth ; 
the  corresponding  inner  surface  of  the  osseous 
mass  of  the  petrous  bone  is  smooth  also,  but 
not  so  much  so.  The  two  surfaces  are  soon 
confounded  together,al though  the  spongy  cellular 
structure  of  the  petrous  bone  can  still,  even  for 
some  time  after  birth,  be  easily  enough  removed 
from  around  the  hard  bony  substance  of  the  laby- 
rinth. Afterwards  they  become  inseparable, 
though  it  is  still  possible  to  perceive  a  trace 
of  the  line  of  demarcation  between  them, 
especially  in  the  cochlea. 

All  the  above  circumstances  show  that  the 
osseous  labyrinth,  though  in  the  petrous  bone, 
is  not  of  it;  and  that,  as  has  been  already  said,  it 
cannot  be  affirmed  to  belongto  the  skeleton,  but 
to  be  merely  embedded  in  a  bone  which  does. 
Moreover  as  Weberf  remarks,  the  osseous  laby- 
rinth is  not  in  all  animals  enclosed  in  the  same 
bone  of  the  skull.;  for  in  fishes,  when  a  trace  of  the 
osseous  labyrinth  is  yet  to  be  found,  the  semi- 
circular canals,  or  the  rudimentary  representa- 
tive of  them,  are  situated  in  the  occipital  bone. 

*  Miicke,  kurze  Uebersicht  der  gegenwartig  be- 
stehenden  Lehr-und-Erziehungsanstalten  fur  Taub- 
itumme  u.  s.  w.  Prag.  1827,  p.  19. 

f  Hildebrandt's  Anatoraie.    Bd.  iv.  p.  40. 


ORGAN  OF  HEARING. 


559 


B.  Development  and  irregular  conditions  of' 
the  tympanum  and  external  ear. 

1.  Of  the  tympanum  and  its  contents. 

1,  The  cavity  of  the  tympanum. — A  prolon- 
gation or  diverticulum  of  the  mucous  mem- 
brane of  the  throat,  extending  to  the  periphe- 
ral surface  of  the  labyrinth,  and  forming,  with 
its  blind  end,  a  dilatation  there,  gives  us  the 
simplest  idea  of  a  tympanum  and  Eustachian 
tube.  According  to  Huschke*— and  his  views 
are  more  or  less  supported  by  Burdach,f 
Rathke,J  and  Valentin,§ — the  cavity  of  the  tym- 
panum with  the  Eustachian  tube  is  a  metamor- 
phosis or  remains  of  the  first  branchial  fissure. 
iJence,  in  its  origin,  the  tympanum  has  nothing 
in  common  with  the  labyrinth. 

Valentin||  found  the  Eustachian  tube  and 
cavity  of  the  tympanum,  in  an  embryo  at  the 
seventh  week,  under  the  form  of  a  conical  or 
pyramidal  fossa.  This  fossa  gradually  extends 
into  a  tube,  at  first  short  and  wide,  but  after- 
wards longer  and  narrower  in  proportion  as  the 
cavity  of  the  tympanum  becomes  developed, 
and  recedes  from  the  cavity  of  the  mouth. 
The  Eustachian  tube  is  at  first  simply  membra- 
neous. About  the  middle  of  pregnancy,  ac- 
cording to  Meckel^  and  Burdach,**  the  third 
month  according  to  Valentin,  it  acquires  a 
cartilaginous  investment. 

The  blind  membraneous  pouch  which  repre- 
sents the  cavity  of  the  tympanum  is  at  first 
very  small  and  contracted,  and  is  to  be  distin- 
guished from  the  walls  of  the  tympanum,  which 
it  invests.  The  peripheral  surface  of  the  laby- 
rinth forms,  as  is  known,  the  inner  solid  wall 
of  the  tympanum,  and  the  tympanic  ring  and 
membrana  tympani  the  outer  wall.  In  pro- 
portion, therefore,  as  these  parts,  and  also  the 
mastoid  process  are  developed,  so  does  the  tym- 
panic cavity  acquire  its  proper  form,  and  is 
more  and  more  withdrawn,  both  from  the  cavity 
of  the  mouth  and  the  lateral  surface  of  the 
head,  with  the  integument  of  which  it  is,  at  an 
early  period,  in  contact. 

The  prolongation  of  the  mucous  membrane 
of  the  pharynx  forming  the  Eustachian  tube 
and  cavity  of  the  tympanum,  is  at  first  very 
vascular,  soft,  and  loose,  like  the  mucous  mem- 
brane of  the  nasal  and  guttural  cavities;  but 
after  birth  it  loses  its  vascularity,  and  assumes 
a  more  simple  character.  United  by  loose 
cellular  tissue  to  the  subjacent  osseous  wall,  it 
applies  itself  over  all  the  elevations,  and  dips 
into  the  depressions  of  it,  and  moreover  forms 
folds  in  which  the  ossicles  are  enveloped.  The 
cavity  of  the  tympanum  is  in  the  foetus  filled 
with  a  mucus,  sometimes  transparent,  some- 

*  Isis  von  Oken,  Jahrg.  1827,  p.  401 ;  Jahrg. 
1828  p.  161;  Jahrg.  1831,  p.  951  ;  and  Meckef's 
Archiv  fur  Anatotnie  nnd  Physiologie,  1832,  p. 

t  Die  Phvsiologie  als  Erfahrungswissenschaft. 
Bd.  ii.  p.  465. 

X  Anat.  physiol.  Untersuchungen  liber  den  Kiem- 
enapparat  und  das  Zungenbein,  1832,  p.  120. 

§  Handbuch  der  Entwickelungsgeschichte  dcs 
Menschen,  p.  211. 

||  L.  c.  p.  211  and  212. 

If  Manuel  d'Anatomie,  &c.  torn.  iii.  s.  1948,  p. 
197.  1 
**  Op.  cit.  Bd.  ii.  p.  465. 


times  bloody,  and  varying  from  the  consistence 
of  water  to  that  of  a  thick  jelly. 

The  cavity  of  the  tympanum  has  been  found 
sometimes  unusually  contracted ;  sometimes, 
on  the  contrary,  very  much  dilated.  Non-de- 
velopment of  the  Eustachian  tube  would  be 
necessarily  attended  by  non-development  of  the 
tympanum,  but.  not  contrariwise.  Absence 
of  the  Eustachian  tube  and  cavity  of  the  tym- 
panum has  only  been  found  in  foetuses,  in  other 
respects  monstrous.  ■ 

In  describing  the  development  of  the  osse- 
ous labyrinth,  it  has  been  already  mentioned 
that  its  peripheral  surface,  which  forms  the 
inner  solid  -wall  of  the  tympanum,  begins  to 
be  ossified  towards  the  end  of  the  third  month. 
An  ossific  point  first  appears  on  the  promontory 
at  the  circumference  of  the  cochlear  fenestra,  and 
gradually  extends  upwards,  downwards,  for- 
wards and  backwards.  At  this  time  there 
is  no  trace  of  mastoid  process.  In  the  fourth 
month  the  sinuositus  mastoidea  begins  to  ap- 
pear, and  the  cavity  of  the  tympanum  be- 
comes somewhat  wider.  The  aqueduct  of  Fal- 
lopius  is  not  yet  ossified,  noi  the  canals  for  the 
muscles  of  the  stapes  and  malleus,  a  state  of 
parts  found  permanent  in  most  of  the  lower  mam- 
mifera,  and  also  frequently  met  with  in  the  irre- 
gular conditions  of  the  ear  in  man.  When  the 
cochlea  is  arrested  in  its  developement,  the  pro- 
montory is  small  in  proportion  or  entirely 
wanting. 

In  the  fifth  mouth  the  aqueduct  ofFallopius 
and  the  canals  for  the  muscles  of  the  stapes  and 
malleus  are  ossified.  In  this  month,  also,  the 
vestibular  fenestra  is  found  completely  formed, 
and  appears  proportionally  larger  than  in  the 
adult.  In  the  sixth  month,  the  temporal  bone 
being  altogether  more  developed,  and  the  mas- 
toid process  having  begun  to  appear,  the  cavity 
of  the  tympanum  increases  in  capacity,  espe- 
cially its  upper  part,  and  the  sinuositas  mas- 
toidea. The  direction  and  situation  of  the 
cochlear  fenestra  vary  much  at  the  different 
periods  of  formation,  which  is  owing  chiefly  to 
the  degree  of  development  of  the  promontory. 

The  vestibular  and  cochlear  fenestra  are 
sometimes  found  unusually  small,  or  even  en- 
tirely wanting,  the  latter  being  obliterated  by 
an  extension  of  osseous  substance,  the  former 
by  the  same  cause,  or  by  anchylosis  of  the 
base  of  the  stapes.  The  cochlear  fenestra  some- 
times appears  to  open  into  the  vestibule,  but  this 
is  when  the  cochlea  is  in  a  very  rudimentary 
state.  Such  a  condition  may  be  compared  with 
the  state  of  parts  found  m  the  bird's  ear. 

Little  or  nothing  is  known  of  the  origin  and 
development  of  the  membrana  tympani.  It 
may  be  looked  upon  as  the  persistence  of  that 
septum  which  exists  at  an  early  period  at 
the  opening  of  all  mucous  canals,  and  which 
is  produced  by  the  meeting  of  the  indentation 
inwards  of  the  skin  with  the  diveiticulum  of 
the  mucous  cavity  of  the  blastoderma.  The 
membrana  tympani  is  larger  in  proportion,  and 
more  vascular  the  younger  the  fcetus  is.  The 
form,  situation,  and  direction  of  it  in  the  fcetus 
is  dependent  on  the  tympanic  ring,  and  is  quite 
different  from  what  is  found  in  the  adult.  In 
regard  to  form,  it  is  rounder.    As  to  situation, 


560 


ORGAN  OF  HEARING. 


the  osseous  portion  of  the  auditory  passage 
not  being  yet  developed,  the  membrana  tympani 
is  found  at  first  closer  to  the  surface  than  after- 
wards; and  its  direction  is  oblique  from  above 
downwards,  and  from  without  inwards,  so  that 
it  has  a  more  or  less  horizontal  position,  corres- 
ponding to  the  base  of  the  cranium. 

More  is  known  of  the  origin  and  develop- 
ment of  the  tympanic  ring  in  which  the  mem- 
brana tympani  is  framed.  It  appears  later 
than  the  membrana  tympani  and  the  ossicles. 
A  specimen  of  the  tympanic  ring  before  me, 
which  was  removed  from  an  embryo  at  about 
the  third  month,  is  an  incomplete  ring  of  bone 
about  one-tenth  of  an  inch  in  diameter.  It  is 
about  the  thickness  of  a  hair,  except  at  its 
anterior  extremity,  which  is  broad  and  flat  like 
a  spatula,  for  the  extent  of  about  one-twelfth 
of  an  inch.  The  groove  for  the  membrana 
tympani  can  be  perceived  with  a  magnifying 
glass.  From  the  fifth  month  the  tympanic  ring 
is  found  more  or  less  adherent  to  the  rest  of 
the  temporal  bone.  In  the  lower  Mammifera 
there  are  three  parts  developed  from  the  tym- 
panic ring,  viz.  1,  the  groove  for  the  mem- 
brana tympani,  2,  the  bulla  ossea,  and  3,  the 
osseous  part  of  the  auditory  passage.  In 
birds  the  tympanic  ring  is  represented  by  the 
os  guadrutum.  In  man  there  is  no  bulla  ossea, 
only  the  groove  for  the  membrana  tympani  and 
the  osseous  part  of  the  auditory  passage.  The 
side  of  the  tympanic  ring  external  to  the  groove 
shoots  out  to  form  the  osseous  part  of  the 
external  auditory  passage,  but  so  slowly  that 
from  the  second  to  the  sixth  or  seventh  year, 
the  lower  surface  of  the  auditory  passage  is 
still  cartilaginous,  although  the  outer  orifice  to 
which  the  cartilaginous  part  of  the  auditory 
passage  is  fixed  is  already  ossified.  About  the 
twelfth  year  the  passage  is  closed  in  by  bone, 
and  becomes  quite  complete  towards  manhood. 
The  inner  surface  of  the  ring  grows  a  little 
at  the  lower  part,  and  helps,  together  with  a 
process  which  extends  from  the  petrous  bone, 
to  form  the  lower  wall  of  the  tympanic  cavity. 
It  is  to  be  remarked  that  this  inner  part  of  the 
tympanic  ring  always  remains  distinct  and  is 
never  changed  so  much  as  the  external. 

Fig.  261. 


The  tympanic  ring,  and  the  membrana  tympani  framed 
into  it.  The  handle  of  the  malleus  is  seen  shining 
through  tfte  membrane. 

The  whole  outer  wall  of  the  cavity  of  the 
tympanum  has  been  found  wanting  in  a  mon- 
strous foetus.  Hyrtl,  who  mentions  the  case, 
says  that  the  cavity  of  the  tympanum  itself 
was  represented  only  by  a  very  shallow  depres- 


sion in  the  petrous  bone,  in  which  the  skin  of 
the  auditory  passage  formed  a  cul-de-sac.  The 
Eustachian  tube  was  present.  Hyrtl  mentions 
another  case  in  which  the  tympanic  ring  was 
much  smaller  than  usual,  and  in  which  the 
membrana  tympani  presented  in  the  direction 
of  one  of  its  radii,  a  large  opening  as  if  a 
piece  had  been  cut  out.  The  so-called  hiatus 
R  ivinianus  ou^ht,  perhaps,  to  be  looked  upon, 
as  Husehke  observes,  as  a  defect  in  original 
formation.  The  membrana  tympani  has  been 
sometimes  found  congenitally  too  large,  some- 
times too  small,  sometimes  of  an  elongated 
form,  sometimes  of  a  triangular  form.  A 
thickening  and  parchment  appearance  of  the 
membrane,  or  ossification  of  it  to  a  greater  or 
less  extent,  if  not  always,  appears  to  be  more 
usually  an  acquired  malformation. 

2.  The  small  bones  of  the  tympanum. — The 
small  bones  are  formed  at  a  very  early  period. 
The  malleus  and  incus  appear  before  the 
stapes.  The  two  former,  according  to  Rathke 
and  Valentin,  appear  like  a  small  wart  growing 
out  from  the  posterior  wall  of  the  tympanum. 
The  stapes  is  like  a  growth  from  the  outer  sur- 
face of  the  labyrinth ;  it  appears  as  a  small 
pyramidal  wart  flattened  on  the  sides  and  thin 
in  the  middle,  lying,  according  to  Rathke,  in 
a  small  funnel-like  depression,  the  bottom  of 
which  is  the  future  vestibular  fenestra. 

According  to  Weber*  the  ossicles  are  not 
developed  in  the  cavity  of  the  mucous  mem- 
brane of  the  tympanic  cavity,  but  in  a  sac 
which  is  a  continuation  of  the  dura  mater,  and 
comes  through  a  fissure  between  the  petrous 
bone  and  the  squamous  portion  of  the  tem- 
poral into  the  tympanic  cavity.  This  situation 
of  the  ossicles  at  an  early  period  corresponds 
with  that  of  those  discovered  by  Weber  in  the 
fishes  already  mentioned.  By  this  mode  of 
development,  as  far  as  regards  situation, 
may  be  explained  the  dislocated  state  of  the 
ossicles  so  frequently  found  in  the  irregular 
conditions  of  the  ear. 

According  to  Meckel,!  the  ossicles  are  at 
the  commencement  of  the  third  month  pro- 
portionally very  large,  though  still  cartilaginous, 
and  the  stapes  not  to  be  distinguished  from  the 
incus.  Thus,  for  example,  the  length  of  the 
malleus  in  a  foetus  of  the  fourth  month  amounts 
to  three  lines,  whilst  the  length  of  the  body 
from  the  vertex  to  the  coccyx  measures  four 
inches,  hence  the  lenght  of  the  malleus  is  to 
that  of  the  trunk  as  one  to  sixteen ;  whereas 
in  the  adult  the  proportion  is  only  as  one  to 
ninety,  the  malleus  being  four  lines  long,  and 
the  distance  between  the  vertex  and  the  coccyx 
amounting  to  two-and-a-half  feet.  At  birth 
the  ossicles  are  as  large  as  in  the  adult. 

Ossification  of  the  small  bones  commences, 
according  to  Burdach,J  about  the  twelfth  week. 
Rathke  and  Valentin  agree  with  Meckel,  that 
ossification  begins  first  and  at  the  same  time  in 
the  malleus  and  incus,  and  only  afterwards  in 
the  stapes.  In  the  malleus  the  first  point  of 
bone  appears  on  the  head,  a  second  at  the  root 


*  Hildebrandt's  Anatomie,  Band;  i 
t  Op.  cit.  torn.  iii.  p.  197.  s.  1948. 
X  Op.  cit.  Band.  ii.  p.  384. 


p.  39. 


ORGAN  OF  HEARING. 


561 


of  the  long  process.  In  the  incus  the  first 
point  of  ossification  occurs  in  the  longer  crus 
near  the  body,  and  from  this  point  it  extends 
during  the  fourth  and  fifth  months,  so  far  that 
the  whole  is  ossified  with  the  exception  of  the 
point  of  the  short  process.  The  long  crus 
Meckel  always  found  completely  ossified, 
whilst  the  short  crus  was  still  cartilaginous. 

The  stapes  is  still  cartilaginous  when  ossi- 
fication has  made  considerable  progress  in  the 
other  two  bones.  According  to  Meckel  ossi- 
fication does  not  commence  at  any  determinate 
point  of  the  stapes ;  only  he  never  observed  it 
first  on  the  head.  According  to  Rathke  there 
are  three  particular  nuclei,  one  for  each  of  the 
sides  of  the  triangle  which  the  stapes  repre- 
sents. 

The  opening  between  the  crura  of  the  stapes 
is  at  first  very  inconsiderable, — a  condition 
analogous  to  what  is  found  permanent  in  the 
Cetacea,  &c. 

The  ossicles  are  not  unfrequently  irregular 
in  their  form,  size,  and  situation.  They  may 
even  be  wanting.  The  stapes,  as  it  is  the  last 
formed,  presents  the  most  numerous  and  most 
varied  malformations  ;  the  malleus  the  fewest. 
The  stapes  has  been  found,  by  Tiedemann, 
as  it  is  at  first,  like  a  pyramid  without  any 
opening  ;  again,  it  has  been  found  with  but  a 
very  small  opening,  or  presenting  indeed  the 
crura,  but  the  space  between  them  filled  up 
by  a  thin  plate  of  bone.  Only  one  crus  has 
been  found  rising  from  the  middle  of  the  base 
in  the  form  of  a  slender  pedicle  of  bone  as  in 
the  bird,  and  presenting  no  trace  of  an  articular 
cavity  for  the  reception  of  the  lenticular  pro- 
cess of  the  incus,  &c. 

A  remarkable  circumstance  connected  with 
the  early  formation  of  the  malleus  is  the 
existence,  as  Meckel*  first  observed,  of  a 
straight  cartilaginous  process,  having  the 
shape  of  a  very  elongated  cone,  which  ex- 
tends from  the  anterior  part  of  the  head 
of  the  malleus  to  the  place  where  the  two 
halves  of  the  lower  jaw  unite  in  front.  The 
cartilaginous  process  passes  out  of  the  cavity 
of  the  tympanum  between  the  petrous  bone 
and  tympanic  ring.  This  process,  though 
having  much  the  same  situation,  must  not  be 
confounded  with  the  processus  gracilis.  The 
former  lies  above  the  latter,  and  both  parts  are 
quite  distinct  from  each  other.  Moreover  the 
cartilaginous  process  never  ossifies,  but  dis- 
appears in  the  eighth  month.  Huschkef  has 
discovered  a  similar  process  extending  be- 
tween the  short  crus  of  the  incus  and  the  supe- 
rior horn  of  the  hyoid  bone  through  the  me- 
dium of  the  styloid  process. 

*  Op.  cit.  torn.  iii.  p.  199.  s.  1948.  See  also 
Huschke  Beitrage  zur  Physiologie  und  Natur- 
gescliichte,  p.  48.  Taf.  ii.  Fig.  1.  Isis  von  Oken, 
1833.  Heft.  vii.  p.  678.  Serres,  Annales  des 
Sciences  Naturelles,  1827,  p.  112.  Weber,  Hilde- 
brandt's  Anatomie,  4te.  Ausgabe.  Band.  iv.  p.  47. 
Rathke,  op.  cit.  p.  122,  and  Valentin,  op.  cit. 
p.  214. 

+  Isis  von  Oken,  loc.  cit.  and  Valentin,  op.  et 
loc.  cit. 

VOL.  II. 

i     i  >       .        >*  ■/ 

>'  "v  ; " !  v. '  '  1 1 1  *  J\  -< 


The  most  interesting  irregular  formation  of 
the  malleus  is  what  appears  to  be  connected 
in  some  manner  with  the  above  described  early 
condition  of  the  malleus  and  incus.  Such 
cases  are  related  by  Hyrtl,*  Heusinger,f  and 
Hesselbach.J 

2.  Of  the  external  ear. — The  external  ear 
soon  disappears  in  the  animal  series.  It  is 
the  last  part  of  the  apparatus  of  hearing 
which  makes  its  appearance  in  the  human 
embryo.  It  is  very  subject  to  irregular  deve- 
lopment. It  is  only  about  the  middle  of  the 
second  month  that  a  trace  of  it  can  be  ob- 
served. It  is  at  first  merely  a  slight  elevation 
of  the  skin,  broad  above,  narrow  below.  In 
the  middle  of  this  elevation  is  a  longitudinal 
fissure  of  the  same  form,  which  is  narrower 
and  at  the  same  time  deeper  from  above 
downwards.  The  prominence  soon  becomes 
more  elevated  and  thinner  at  its  posterior  part, 
and  projects  above  the  surface  of  the  side 
of  the  head,  from  which  circumstance  the 
middle  depression  is  a  little  exposed.  At  the 
same  time  or  soon  after,  the  anterior  part  of 
the  prominence  is  found  divided  into  two 
halves  by  a  transverse  fissure  running  forwards; 
the  inferior  half  is  the  antitragus,  and  the  supe- 
rior the  commencement  of  the  helix.  At  the 
same  time  this  anterior  part  of  the  external  ear 
rises  also,  and  the  posterior  spreads  more  out. 
In  the  third  month  the  anthelix  and  tragus  are 
developed  ;  the  concha  is  not  yet  perfectly  dis- 
tinct; it  is  only  indicated  by  the  middle  de- 
pression. In  the  fourth  and  fifth  month  the 
hollow  of  the  concha  appears,  and  is  completely 
formed  in  the  sixth.  The  lobule  is  the  last  part 
which  presents  itself. 

The  cartilage  begins  to  be  formed  in  the 
third  month,  but  is  developed  slowly.  To- 
wards the  end  of  pregnancy,  though  thicker, 
harder,  and  firmer,  it  is  still  incomplete. 

The  cartilaginous  portion  of  the  auditory 
passage  as  well  as  the  auricle  is  at  first  pro- 
portionally much  smaller  than  afterwards.  The 
skin  lining  the  auditory  passage  is  softer  and 
thicker  than  in  the  adult,  and  is  covered  with 
a  thickly  set  down.  In  the  foetus  the  auditory 
passage  is  rounder,  straighter,  and  shorter  than 
in  the  adult. 

The  auricles  may  not  be  formed  at  all,  or 
their  development  may  be  so  arrested  that  they 
shall  be  represented  merely  by  unshapely  folds 
of  skin  with  or  without  cartilage,  or  they  may 
deviate  more  or  less  from  their  usual  form, 
size,  and  situation.  Imperfect  formation  of 
the  auricle  is  frequently  accompanied  by  ab- 
sence or  closure  of  the  auditory  passage.  Pro- 
fessor Samuel  Cooper  mentions  the  case 
of  a  child  in  which  there  was  not  the  slightest 
trace  either  of  external  ear  or  auditory  passage. 

*  Op.  et  loc.  cit. 

f  Specimen  mala;  conformationis  organorum 
auditus  human!  rarissimum  et  memoratu  dignis- 
simum,  cum  tvibus  tabulis  aeri  incisis.  Jenae, 
1824. 

%  Beschreibung  der  pathologischen  Priiparate, 
welche  in  der  kbniglichen  anatomischen  Anstalt 
zu  VVurzburg  aufbewahit  werden.  Giessen,  1824. 

2  P 


562 


ORGAN  OF  HEARING. 


Sometimes,  however,  the  auditory  passage  has 
been  found  regular  though  the  auricles  were 
wanting. 

The  auditory  passage  is  sometimes  found  too 
wide,  sometimes  too  narrow,  sometimes  too 
short.  Closure  of  the  auditory  passage  may 
be  either  partial  or  through  its  whole  extent. 
It  is  move  rarely  the  effect  of  disease  than  of 
irregular  primitive  formation.  Partial  closure 
may  be  by  an  extension  of  the  skin  over  the 
mouth  of  the  passage.  Authors  mention  cases 
of  a  membraneous  septum  sometimes  deep  in 
the  auditory  passage  and  before  the  membrana 
tympani,  sometimes  nearer  the  entrance  of  the 
passage. 

In  monstrous  foetuses  all  the  accessory  parts 
of  the  apparatus  of  hearing  together  have  been 
found  wanting. 

II.    PARALLEL    BETWEEN  THE  EAR  AND 
THE  EYE. 

A  parallel  has  often  been  drawn  betwixt  the 
ear  and  the  eye.  Breschet,  in  his  memoir, 
already  so  often  cited  in  the  course  of  this 
article,  compares  the  perilymph  to  the  aqueous 
humour,  the  endolymph  to  the  vitreous  hu- 
mour, and  the  calcareous  concretions  to  the 
crystalline  body. 

The  comparison  which  I  should  institute 
between  the  component  parts  of  the  ear  and 
the  eye  is  the  following: — 

The  osseous  labyrinth  may  be  compared  to 
the  sclerotica,  and  the  fenestra  rotunda,  or  coch- 
lear fenestra,  to  the  cornea. 

To  find  a  part  in  the  eye  analogous  to  the 
vestibular  fenestra,  we  must  first  consider  that 
the  latter  is  a  yielding  part  of  the  otherwise 
solid  wall  of  the  labyrinth ;  that  through  the 
medium  of  it,  the  chain  of  small  bones  and 
their  muscles  in  the  tympanum  exercise  on  the 
soft  parts  contained  in  the  labyrinthic  cavity, 
a  certain  degree  of  tension  or  compression 
fitted  probably  to  accommodate  in  some  man- 
ner the  ear  to  the  perception  of  different 
degrees  of  sound.  In  the  case  of  the  eye, 
the  sclerotica,which  corresponds  to  the  osseous 
labyrinth,  is  thinner  and  more  yielding  at  the 
middle  of  its  circumference,  (remarkably  so  in 
the  Greenland  seal).  From  this  it  has  been 
supposed  that  the  action  of  the  muscles  of  the 
eye-ball  might  by  their  compression  produce 
a  change  of  shape  fitted  to  accommodate  the 
eye  to  distances.  Hence  the  vestibular  fenestra 
and  middle  thin  part  of  the  sclerotica  might 
be  compared  to  each  other  in  as  far  as  regards 
the  function  which  each  performs  in  the  eco- 
nomy of  its  own  organ.  However  this  may  be, 
the  vestibular  fenestra  of  the  ear  and  the  thin 
part  of  the  sclerotica  correspond  to  each  other 
as  far  as  can  be  in  relative  position ;  and  if  we 
admit  the  action  just  mentioned  of  the  muscles 
upon  the  eye-ball,  we  have,  as  I  shall  imme- 
diately show,  their  counterparts  in  the  muscles 
of  the  small  bones  of  the  tympanum. 

The  tympanic  scala  of  the  cochlea  may  be 
compared  to  the  anterior  chamber  of  the 
aqueous  humour,  and  the  vestibular  scala  to 
the  posterior  chamber. 


The  spiral  lamina,  considering  its  vascu- 
larity and  richness  in  nerves,  and  its  forming 
a  partition  between  two  chambers  containing 
an  aqueous  humour,  may,  as  I  have  already 
said  in  a  former  part  of  this  article,  be  con- 
sidered the  counterpart  of  the  iris,  and  the 
helicotrema  that  of  the  pupil. 

The  membrane  lining  the  labyrinthic  cavity 
bears  the  same  relation  to  the  latter  as  the 
arachnoidea  ticuli*  does  to  the  sclerotica.  The 
space  filled  with  perilymph,  between  the  osse- 
ous and  membraneous  labyrinth,  may  be  con- 
sidered analogous  to  that  between  the  sclerotica 
and  choroid.  It  however  communicates  with 
the  scalae  of  the  cochlea,  the  parts  analogous 
to  the  chambers  of  the  aqueous  humour,  be- 
cause there  is  nothing  in  the  ear  to  be  com- 
pared to  the  ciliary  ligament. 

Forming  the  membraneous  labyrinth  we  find, 

1.  a  delicate  cellular  tissue  supporting  the 
branches  of  the  bloodvessels,  and  which  is 
sometimes  found  containing  black  pigment ; 

2.  a  firm  transparent  membraneous  coat,  within 
which,  3.  is  a  nervous  expansion  ;  4.  the  endo- 
lymph; 5.  suspended  in  the  latter  the  mass  of 
calcareous  matter.  The  cellulo-vascular  layer 
containing  pigment,  together  with  the  rest  of 
the  walls  of  the  membraneous  labyrinth,  may 
be  compared  to  the  choroid  coat  of  the  eye, 
the  nervous  expansion  to  the  retina,  the  endo- 
lymph to  the  vitreous  humour,  and  the  calca- 
reous mass  to  the  lens. 

In  the  lower  animals  the  cochlea  is  the  first 
part  of  the  ear-bulb  to  disappear ;  in  regard  to 
the  eye-ball,  the  aqueous  chambers  to  which 
I  have  compared  the  scalae  of  the  cochlea,  are 
in  like  manner  the  first  parts  which  in  the  de- 
preciation of  the  structure  of  the  eye,  in  the 
animal  series,  disappear,  e.  g.  the  eye  of  the 
Cephalopodous  Mollusca. 

Is  the  cochlear  nerve  the  same  in  function 
with  the  vestibular?  The  vestibular  nerve  is 
the  special  nerve  of  hearing ;  but  does  not  the 
cochlear  nerve  perform  some  function  in  the 
economy  of  the  ear  analogous  to  what  the 
ciliary  nerves  perform  in  that  of  the  eye  ? 

If  an  example  is  required  in  which  the  optic 
nervous  filaments  enter  the  eye  separately  as 
do  the  nervous  filaments  of  the  ear-bulb,  it  is 
to  be  found  in  the  Cephalopodous  Mol- 
lusca.f 

As  in  front  of  the  eyeball  there  is,  or  rather 
would  be,  if  it  was  not  that  the  eyelids  are 
constantly  in  contact  with  the  eyeball,  a  space 
lined  by  a  mucous  membrane,  the  conjunctiva, 
so  at  the  peripheral  surface  of  the  ear-bulb, 
there  is  a  space,  the  tympanic  cavity,  lined  by 
a  mucous  membrane  also.  Moreover,  as  there 
is  a  passage  into  the  nose  from  the  space 
bounded  by  the  conjunctiva,  so  does  the  tym- 

*  See  mv  figure  and  description  of  a  horizontal 
section  of  the  human  eye,  in  Mackenzie's  Practical 
Treatise  on  Diseases  of  the  Eye.  Second  Edition. 
London,  1835. 

t  See  a  paper  "  On  the  Retina  of  the  Cuttle- 
fish," in  the  London  and  Edinburgh  Philosophical 
Magazine  for  January,  1836. 


ORGAN  OF  HEARING. 


563 


panic  cavity  communicate  with  the  throat  by 
the  Eustachian  tube.  In  the  tympanic  cavity 
there  is  a  chain  of  small  bones,  articulated  to 
each  other  and  moved  by  muscles,  which 
serves  to  produce  some  change  in  the  state  of 
tension  of  the  soft  parts  of  the  ear-bulb ;  in 
the  conjunctival  space  there  is  nothing  analo- 
gous, although,  without  pushing  the  point  too 
far,  we  might  compare  the  muscles  of  the  eye- 
ball with  those  of  the  ossicles  of  the  tym- 
panum, both  being  equally,  in  fact,  outside 
their  respective  mucous  membranes.  In  re- 
gard to  the  ossicles  I  would  remark  that, 
according  to  the  views  of  Weber,*  they  must 
be  reckoned  among  those  which  do  not  belong 
to  the  skeleton,  and  which  are  of  very  incon- 
stant occurrence.  Such  are  the  bone  of  the 
penis  in  many  animals,  the  teeth,  the  ring  of 
bony  plates  round  the  front  of  the  sclerotica  of 
the  bird's  eye,  SfC. 

Apart  in  the  composition  of  the  appendages 
of  the  eye  analogous  to  the  membrana  tym- 
pani  is  only  to  be  conceived  by  supposing  the 
existence  of  a  mediate  ankyloblepharon,  that 
is,  an  irregular  membrane  stretched  between 
the  edges  of  the  eyelids,  uniting  them  toge- 
ther and  closing  in  the  space  lined  by  the  con- 
junctiva, which  space  would  now  communi- 
cate with  the  exterior,  only  by  the  lachrymal 
canalicules  and  nasal  duct,  in  the  same  way 
that  the  tympanic  cavity  communicates  with 
the  exterior  only  by  the  Eustachian  tube.  A 
congenital  fissure  or  total  absence  of  the  mem- 
brana tympani  is  an  irregularity  of  structure 
in  the  ear,  which  may  be  compared  to  what  is 
regular  in  the  eye.  A  mind  accustomed  to 
trace  analogies  will  perceive  a  resemblance  : — 
to  the  external  auditory  passage  in  that  short 
space  at  the  opening  of  the  eyelids  extending 
from  the  inner  edge  of  the  tarsal  margin  to  the 
outer ;  to  the  ceruininous  glands  in  the  Mei- 
bomian follicles;  and  to  the  hairs  at  the  en- 
trance of  the  auditory  passage  in  the  eyelashes. 
The  auricle,  if  it  is  necessary  to  look  for  a  part 
corresponding  to  it,  may  be  placed  in  the  same 
category  with  the  eyebrows. 

Bibliography.— General  Works  on  the  Organ 
of  Hearing. 

Gabriel  Fallopius,  Observationes  Anatomicae. 
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l'oreille  ;  ed.  cum  Lamy  explic.  median,  des  fonc- 
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Joseph  du  Verney,  Observation  sur  l'organe  de 
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*  Hildebrandt's  Anatomie,  Band.  iv.  p.  39. 


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usages  et  les  maladies  de  toutes  les  parties  de 
l'oreille.  Paris,  1683-1718,  12mo.  Leide,  1731, 
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humana  tractatus,  &c.  Genevae,  1716,  4to.  Ditto, 
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2  P  2 


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4to.  with  the  table  of  Santorini. 

On  the  ear-wax . —  Haygarth,  in  Medical  Observa- 
tions and  Inquiries,  vol.  iv.  edit.  2,  1772,  p.  198- 
205.  Berzelius,  Lehrbuch  der  Thierchemie.  Dres- 
den, 1831,  8vo.  p.  440. 

On  the  comparative  anatomy  of  the  ear. — J.  Hunter, 
An  account  of  the  organ  ot  hearing  in  fishes,  in 
Phil.  Trans,  and  Animal  Economy.  The  works  of 
Scarpa,  Comparetti,  Monro,  Pohl,  Weber,  and  De 
Blainville,  already  mentioned.  G.  R.  Treviranus, 
Ueber  den  inneren  Bau  der  Schnecke  des  Ohrs  der 
Vbgel,  in  Tiedemann  und  Treviranus  Zeitschrift 
fur  Physiologie.  B.  i.  188-196.  C.J.  H.  Windisch- 
mann,  De  penitiore  auris  in  Amphibiis  structura. 
Lipsias,  1831.  G.  Breschet,  Recherches  anato- 
miques et  physiologiques  sur  l'organe  de  l'audition 
chez  les  oiseaux.  Paris,  1836,  in  8vo.  and  atlas 
in  fol.  Ditto,  Sur  l'organe  de  l'Audition  chez  les 
Poissons.    Paris,  1837. 

C  T.  Wharton  Jones.) 

HEARING  (in  Physiology,)  audition  ;  Lat. 
auditus;  Fr.  l'audition,  sens  de  l'ouie;  Germ. 
das  Gehor,  Gehorsinn. — Of  all  the  senses,  that 
of  hearing  is  the  most  valuable  to  man  in  his 
social  condition,  for  without  it  all  interchange 
of  ideas  through  the  medium  of  a  spoken 
language  would  be  impossible.  To  it  indeed, 
as  a  distinguished  metaphysician  has  remarked, 
we  are  indirectly  indebted  for  the  use  of  verbal 
language.  By  the  sense  of  hearing  men  and 
animals  take  cognizance  of  sounds  and  distin- 
guish their  varieties,  the  almost  innumerable 
multitude  of  which  may  well  excite  our  admi- 
ration of  the  sense.  "  Who,"  says  the  excel- 
lent Derham,  "  who  but  an  intelligent  Being, 
what  less  than  an  omnipotent  and  infinitely 
wise  God,  could  contrive  and  make  such  a  fine 
body,  such  a  medium,  so  susceptible  of  every 
impression  that  the  sense  of  hearing  liath  occasion 


HEARING. 


565 


for,  to  empower  all  animals  to  express  their 
sense  and  meaning  to  others ;  to  make  known 
their  fears,  their  wants,  their  pains  and  sorrows 
in  melancholick  tones;  their  joys  and  pleasures 
in  more  harmonious  notes;  to  send  their  minds 
at  great  distances  in  a  short  time  in  loud 
boations ;  or  to  express  their  thoughts  near  at 
hand  with  a  gentle  voice  or  in  secret  whispers. 
And  to  say  no  more,  who  less  than  the  same 
most  wise  and  indulgent  Creator  could  form 
such  an  ceconomy  as  that  of  melody  and  musick 
is ;  that  the  medium  should,  as  I  said,  so 
readily  receive  every  impression  of  sound,  and 
convey  the  melodious  vibration  of  every  musi- 
cal string,  the  harmonious  pulses  of  every 
animal  voice,  and  of  every  musical  pipe;  and 
the  ear  be  as  well  adapted  and  ready  to  receive 
all  these  impressions  as  the  medium  to  convey 
them.  And  lastly,  that  by  means  of  the  curious 
lodgment  and  inosculation  of  the  auditory 
nerves,  the  orgasms  of  the  spirits  should  be 
allayed  and  perturbations  of  the  mind  in  a  great 
measure  quieted  and  stilled ;  or  to  express  it 
in  the  words  of  the  last-cited  famous  author 
(Willis),  '  that  musick  should  not  only  affect 
the  fancy  with  delight,  but  also  give  relief  to 
the  grief  and  sadness  of  the  heart ;  yea,  appease 
all  those  turbulent  passions  which  are  excited 
in  the  breast  by  an  immoderate  ferment  and 
fluctuation  of  the  blood.'" 

Preliminary  observations  on  sound:* — Sound 
is  the  result  of  an  impulse  of  any  kind  con- 
veyed by  the  air  to  our  ears.  The  analysis 
of  what  takes  place  on  the  production  of  various 
familiar  sounds  or  noises  abundantly  explains 
this.  If  the  ear  be  applied  to  one  extremity  of 
a  long  beam  of  timber  and  a  person  tap  with 
his  finger  on  the  other,  the  impulse  is  distinctly 
perceived  by  the  impression  of  sound  which  is 
conveyed.  A  fine  probe  introduced  carefully 
through  the  meatus  externus,  and  made  to 
impinge  upon  the  membrana  tympani,  however 
gently,  will  occasion  the  sensation  of  sound. 
To  produce  the  sensation,  then,  of  sound,  an  im- 
pulse is  necessary  either  of  some  solid  directly 
upon  the  membrane  of  the  tympanum  itself,  or 
of  the  air  which  is  always  in  contact  with  that 
membrane.  The  body  by  which  the  sound  is 
produced,  denominated  by  Professor  Wheat- 
stone  f  a  phonic,  occasions  in  the  surrounding 
air  vibrations  or  oscillations,  corresponding  in 
number  and  extent  to  those  which  exist  in 
itself;  and  these  vibrations  or  oscillations  being 
propagated  to  the  organ  of  hearing,  give  rise  to 
the  sensation.  This  agitation  of  the  air  sur- 
rounding the  body  from  whence  the  sound 
emanates  is  manifest  in  numerous  instances  ; — 
the  report  of  a  cannon,  the  rushing  of  waters,  the 
rattling  of  carriages,  which  in  the  crowded  tho- 
roughfares of  London  communicate  their  vibra- 
tions to  the  walls  and  floors  of  the  houses  and 
even  to  the  furniture.   In  the  familiar  instance 

*  It  will  be  perceived  that  in  the  ensuing  obser- 
vations the  writer  has  borrowed  largely  from  Sir 
John  Herschel's  admirable  essay  on  sound  in  the 
Encyclopedia  Metropolitana.  He  has  also  to 
acknowledge  his  obligations  to  the  article  on  Acous- 
tics in  Pouillet's  Elcmens  dc  Physique. 

f  Annals  of  Philosophy,  new  series,  vol.  vi. 


of  eliciting  sound  from  a  finger-glass  partly  full 
of  water  by  rubbing  the  wetted  finger  round  its 
brim,  the  vibrations  which  this  friction  excites 
in  the  glass  are  rendered  evident  by  the  crispa- 
tions  produced  in  the  water  immediately  in 
contact  with  it.  The  vibration  of  the  water,  as 
indicated  by  these  crispations,  corresponds  with 
that  of  the  glass — the  greater  the  intensity  of 
the  sound  elicited,  the  more  considerable  are 
the  vibrations  in  the  glass,  and  consequently 
the  more  manifest  are  those  of  the  water,  and 
vice  versa.  "  In  musical  sounds  we  may  also 
observe  an  agitation  which  is  often  felt  commu- 
nicating itself  to  the  surrounding  bodies.  If, 
for  example,  we  stand  under  or  near  a  piano- 
forte when  it  is  sounding',  we  feel  a  sensible 
tremor  in  the  floor  of  the  apartment.  If  we 
lay  the  finger  or  hand  on  the  instrument  or 
touch  any  other,  such  as  a  violin  when  it  is 
sounding,  or  a  bell,  we  feel  the  same  sort  of 
tremor  in  every  part  of  them;  and  this  is  well 
observed  in  the  case  of  any  glass  vessel,  such 
as  a  tumbler  or  large  cup.  If  we  strike  it  so 
as  to  make  it  sound,  and  then  touch  the  mouth 
of  it  with  the  finger,  we  feel  a  sensible  tremor 
in  the  glass;  and  when  this  internal  agitation 
is  stopped,  as  it  generally  is  by  the  contact 
with  the  finger,  then  the  sound  ceases  along 
with  it."* 

The  disturbance  produced  in  the  air  by  a 
sounding  body  has  been  from  a  very  early 
period  illustrated  by  a  reference  to  the  waves 
formed  in  still  water  by  a  stone  falling  into  it. 
"  Voice,"  says  Vitruvius,  "  is  breath  flowing 
and  made  sensible  to  the  hearing  by  striking 
the  air.  It  moves  in  infinite  circumferences  of 
circles,  as  when,  by  throwing  a  stone  into  still 
water,  you  produce  innumerable  circles  of 
waves,  increasing  from  the  centre  and  spread- 
ing outwards,  till  the  boundary  of  the  space  or 
some  obstacle  prevents  their  outlines  from  going 
further.  In  the  same  manner  the  voice  makes 
its  motions  in  circles.  But  in  water  the  circles 
move  breadthways  upon  a  level  plane;  the 
voice  proceeds  in  breadth,  and  also  successively 
ascends  in  height."f  That  the  presence  of  air  is 
necessary  for  the  production  of  sound  is  proved 
by  the  experiment  first  tried  by  HauksbeeJ  and 
repeated  by  Biot.  A  bell  was  made  to  ring  in 
the  receiver  of  an  air-pump,  and  in  proportion 
as  the  air  was  exhausted  it  was  found  that  the 
sound  died  away,  and  it  again  returned  as  the 
air  was  re-admitted.  On  the  other  hand,  the 
bell  sounded  more  strongly  when  the  air  within 
the  receiver  was  condensed,  and  the  greater  the 
condensation  of  the  air,  the  louder  was  the 
sound. 

Any  irregular  impulse  communicated  to  the 
air  produces  a  noise,  in  contradistinction  to 
a  musical  sound.  This  latter  results  from  a 
succession  of  impulses,  which  occur  at  ex- 
actly equal  intervals  of  time,  and  which  are 
exactly  similar  in  duration  and  intensity. 
When  these  impulses  succeed  each  other  with 
great  rapidity,  the  sound  appears  continuous, 

*  Encycl.  Britann.  art.  Acoustics, 
t  Vitruvius  de  Arch.  v.  3,  quoted  in  Whewell's 
History  of  the  Inductive  Sciences. 
1  Phil.  Trans.  1705. 


566 


HEARING. 


in  consequence  of  the  duration  of  the  impres- 
sion upon  the  auditory  nerve.  The  frequency 
of  repetition  necessary  for  the  production  of  a 
continued  sound  from  single  impulses  is, 
according  to  Sir  J.  Herschel,  probably  not  less 
than  sixteen  times  in  a  second,  though  the 
limit  would  appear  to  differ  in  different  ears. 

We  distinguish  in  musical  sounds,  1,  the 
pitch  ;  2,  the  intensity  or  loudness ;  3,  the 
quality.  The  pitch  of  the  sound  depends  on 
the  rapidity  with  which  the  vibrations  succeed 
each  other,  and  any  two  sounds  produced  by 
the  same  number  of  vibrations  or  impulses  in 
the  same  time  are  said  to  be  in  unison.  The 
loudness  or  intensity  depends  upon  the  violence 
and  extent  of  the  primitive  impulse.  The  quality 
is  supposed  by  Sir  J.  Herschel  to  depend  on  the 
greater  or  less  abruptness  of  the  impulses,  or 
generally,  on  the  law  which  regulates  the  excur- 
sions of  the  molecules  of  air  originally  set  in 
motion. 

Sound  may  be  communicated  by  air,  aeri- 
form fluids,  liquids  or  solids,  with  variable 
degrees  of  velocity.  In  air  at  the  temperature 
of  62°  Fahr.  sound  travels  at  the  rate  of  1125 
feet  in  a  second,  or  1090  feet  in  a  second  in 
dry  air  at  the  freezing  temperature. 

The  velocity  with  which  sound  travels  is, 
however,  quite  independent  of  its  intensity  or 
its  tone;  sounds  of  all  pitches  and  of  every 
quality  travel  with  equal  speed,  as  is  proved 
by  the  fact  that  distance  does  not  destroy  the 
harmony  of  a  rapid  piece  of  music  played  by 
a  band.  If  notes  of  a  different  pitch  travelled 
with  different  velocities,  they  would  not  reach 
the  ear  in  the  order  in  which  they  were  played. 
Moreover,  Biot  put  it  to  the  test  of  direct  ex- 
periment ;  he  caused  several  tunes  to  be  played 
on  a  flute  at  the  end  of  a  pipe  3120  feet  long, 
and  found  that  they  could  be  distinctly  heard 
without  the  slightest  derangement. 

Neither  is  the  velocity  of  sound  affected  by 
an  increase  of  density  in  the  air.  It  is,  how- 
ever, greater  in  warm  than  in  cold  air  in  conse- 
quence of  the  greater  elasticity  of  the  former. 
In  the  different  gases  much  variety  has  been 
observed  in  the  velocity  of  sound  ;  through  car- 
bonic gas  the  rate  of  the  velocity  is  said  to  be 
one-third  slower  than  ordinary,  but  through  hy- 
drogen gas,  which  is  twelve  times  more  elastic 
than  common  air,  the  speed  exceeds  the  usual 
rate  three  and  a  half  times.  A  more  striking 
difference  is  as  regards  the  intensity  of  sound 
or  the  impression  it  is  capable  of  producing  on 
our  organs  of  hearing.  This  varies  conside- 
rably with  the  increase  or  diminution  in  the 
density  of  the  transmitting  gas.  By  means  of 
a  piece  of  clock-work,  which  caused  a  ham- 
mer to  strike  at  regular  intervals,  the  conduct- 
ing power  of  the  gas  could  be  estimated,  the 
clock-work  being  placed  in  a  glass  receiver  filled 
with  the  gas.  It  was  thus  that  Priestley  ascer- 
tained that  in  hydrogen  the  sound  was  scarcely 
louder  than  in  vacuo;  in  carbonic  acid  and  in 
oxygen  it  was  somewhat  louder  than  in  air. 

Water  can  transmit  sound,  as  the  anatomist 
would  infer  must  be  the  case  from  the  fact 
that  fishes  are  provided  with  distinct  and  highly 
developed  organs  of  hearing.    Hauksbee,  An- 


deron,  the  Abbe"  Nollet,  and  Franklin  have 
abundantly  proved  this  by  their  experiments. 
M.  Colladon,  by  means  of  a  tin  cylinder  three 
yards  long  and  eight  inches  in  diameter,  closed 
at  its  lower  end  but  open  to  the  air  above, 
plunged  vertically  in  the  water,  was  enabled  to 
hear  the  sound  of  a  bell  at  a  distance  of  about 
nine  miles,  and  from  numerous  observations 
he  concluded  that  the  velocity  of  sound  in 
water  at  about  46°  Fahr.  was  equal  to  4708 
feet  in  the  second. 

Solids  convey  sound  as  well  as  or  even 
better  than  air  or  liquids.  Elasticity  and  ho- 
mogeneousness  are  the  qualities  which  best 
adapt  solids  for  the  conveyance  of  sound : 
hard  substances,  then,  which  are  the  most 
elastic,  conduct  sound  best.  An  interesting 
experiment  of  Hassenfratz  and  Gay  Lussac,  in 
the  quarries  of  Paris,  affords  a  striking  contrast 
of  the  relative  conducting  powers  of  air  and 
solids.  A  blow  of  a  hammer  against  the  rock 
produced  two  sounds  which  separated  in  their 
progress ;  that  propagated  through  the  stone 
arrived  almost  instantly,  while  the  sound  con- 
veyed by  the  air  lagged  behind.  A  more  re- 
markable experiment  was  that  of  Herhold  and 
Rahn,  related  by  Chladni: — a  metallic  wire 
600  feet  long  was  stretched  horizontally,  and 
at  one  end  a  plate  of  sonorous  metal  was 
attached ;  when  the  plate  was  slightly  struck, 
a  person  at  the  opposite  end,  holding  the  wire 
in  his  teeth,  heard  at  every  blow  two  distinct 
sounds,  the  first  transmitted  almost  simulta- 
neously by  the  metal,  the  other  arriving  later 
through  the  air.  Biot,  with  the  assistance  of 
Messrs.  Boulard  and  Malus,  concluded  the 
velocity  of  sound  in  cast  iron  at  the  tempera- 
ture 51°  Fah.  to  be  11,090  feet  in  a  second. 

litjiexion  of  sound. — Sonorous  undulations 
in  passing  from  one  medium  to  another  always 
experience  a  partial  reflexion,  and  when  they 
encounter  a  fixed  obstacle,  they  are  wholly 
reflected ;  and  in  both  cases  the  angle  of  in- 
cidence is,  as  in  the  reflexion  of  light,  equal  to 
the  angle  of  reflexion. 

Echos  are  sounds  reflected  from  some  ob- 
stacle which  is  placed  in  their  way,  as  the  wall 
of  a  house,  or  those  of  an  apartment,  or  the 
surface  of  a  rock,  or  the  vaulted  roof  of  a 
church,  &c;  and  a  sound  thus  reflected  may, 
by  meeting  another  similar  obstacle,  be  again 
reflected,  and  thus  the  echo  may  be  repeated 
many  times  in  succession,  becoming,  however, 
fainter  at  each  repetition  till  it  dies  away  alto- 
gether. The  phenomena  of  echos  illustrate 
beautifully  the  analogy  between  sound  and 
light.  Thus,  the  reflexion  of  sound  from  con- 
cave and  convex  surfaces  takes  place  exactly  as 
in  the  case  of  light :  if  a  reflecting  surface  be 
concave  towards  an  auditor,  the  sounds  re- 
flected from  its  several  points  will  converge 
towards  him,  exactly  as  reflected  rays  of  light 
do ;  and  he  will  receive  a  sound  more  intense 
than  if  the  surface  were  plane,  and  the  more 
so  the  nearer  it  approaches  to  a  sphere  con- 
centric with  himself;  the  contrary  is  the  case 
if  the  echoing  surface  be  convex.  If  the 
echo  of  a  sound  excited  at  one  station  be 
required  to  be  heard  most  intensely  at  another, 


HEARING. 


567 


the  two  stations  ought  to  be  conjugate  foci  of 
the  reflecting  surface,  i.  e.  such  that  if  the 
reflecting  surface  were  polished,  rays  of  light 
diverging  from  one  would  be  made  after  re- 
flexion to  converge  to  the  other.  Hence,  if  a 
vault  be  in  the  form  of  a  hollow  ellipsoid  of 
revolution,  and  a  speaker  be  placed  in  one 
focus,  his  words  will  be  heard  by  an  auditor  in 
the  other,  as  if  his  ears  were  close  to  the  other's 
lips.  The  same  will  hold  good  if  the  vault  be 
composed  of  twosegments  of  paraboloids  having 
a  common  axis,  and  their  concavities  turned 
towards  each  other;  only  in  this  case  sounds 
excited  in  the  focus  of  one  segment  will  be 
collected  in  the  focus  of  the  other  after  two 
reflexions. 

The  most  favourable  circumstances  for  the 
production  of  a  distinct  echo  from  plane  sur- 
faces is  when  the  auditor  is  placed  between  two 
such  exactly  half-way.  In  this  situation  the 
sounds  reverberated  from  both  will  reach  him 
at  the  same  instant,  and  reinforce  each  other : 
if  nearer  to  one  surface  than  the  other,  the  one 
will  reach  him  sooner  than  the  other,  and  the 
echo  will  be  double  and  confused.* 

We  propose  to  enquire  the  part  which  each 
portion  of  the  complex  auditory  apparatus  of 
man  performs  in  the  function  of  hearing. 

I.  Of  the  internal  ear. — The  fact  that  a 
part,  answering  precisely  to  the  vestibule,  is  to 
be  met  with  in  every  class  of  animals  in  whom 
an  auditory  apparatus  can  be  detected,  affords 
a  strong  presumption  that  this  portion  of  the 
labyrinth  is  the  essential  part  of  the  organ. 
Here  is  the  seat  of  the  principal  expansion  of 
the  auditory  nerve  upon  the  saccule  and 
common  sinus,  which  floating  in  the  perilymph 
communicate,  through  the  medium  of  that  fluid, 
with  the  membrane  of  the  fenestra  ovalis,  and 
consequently  with  the  air  contained  in  the  tym- 
panum. Any  vibrations  or  oscillations  then 
excited  in  the  membrane  of  the  fenestra  ovalis, 
cannot  fail  to  affect  the  perilymph  to  a  propor- 
tional extent,  and  through  it  the  membranous 
vestibule.  In  the  simple  ear  of  Crustaceans 
as  well  as  that  of  Cephalopods  and  the  lowest 
Cyclostomous  fishes,  the  sonorous  impressions 
are  conveyed  directly  to  the  vestibular  cavity 
through  the  solid  material  in  which  that  cavity 
is  formed,  or,  as  in  some  Crustaceans,  through 
the  vibration  of  an  external  membrane. 

In  the  higher  organized  fishes,  too,  the 
labyrinth  constitutes  the  whole  of  the  auditory 
apparatus,  nor  has  it  any  kind  of  opening  to  or 
communication  with  the  external  air,  being 
lodged  in  the  walls  or  cavity  of  the  cranium, 
the  sonorous  impressions  must  be  conveyed 
through  the  solid  cranial  parietes ;  for,  in  truth, 
there  is  no  other  mode  in  which  they  can  be 
conveyed,  and  we  know  that  solids  are  even 
better  conductors  of  sound  than  either  liquids 
or  aerial  fluids.f 

As  to  the  function  performed  by  the  otolithes, 

*  Herschel,  Encycl.  Metrop. 

t  Hunter,  Monro,  Weber,  and  Treviranus,  how- 
ever, describe  a  communication  with  the  exterior  in 
Rays  and  the  Shark  by  two  long  canals  ;  but  Scarpa, 
Bell,  and  Blainville  positively  deny  that  these 
ducts  perform  the  office  of  auditory  canals,  j 


or  the  calcareous  dust,  otokonies,  which  are 
found  in  the  sacculus  vestibuli  of  the  ears  of 
Cephalopods  and  Fishes,  no  satisfactory  theory 
has  as  yet  been  offered  by  any  physiologist. 
Although  it  is  now  admitted  that  similar  cal- 
careous particles  exist  in  the  vestibules  of  all 
vertebrated  animals,  still  they  are  only  in  a 
rudimental  condition  when  compared  with 
those  of  fishes  ;  indeed  it  seems  not  unreason- 
able to  suppose  that  the  calcareous  dust  or 
otokonie  of  cartilaginous  fishes  (the  ray  or 
shark  for  example)  is  rudimental  of  the  hard, 
porcellaneous,  and  artfully  formed  otolithe  of 
the  osseous  fishes.*  A  sort  of  loose  notion 
seems  to  prevail,  that  the  presence  of  this  hard 
body  in  the  vestibule  favours  the  communication 
of  sound,  by  impinging  upon  the  expansion  of 
the  auditory  nerve.  The  following  obser- 
vations of  Camper  no  doubt  propagated  this 
idea,  if  they  did  not  originally  give  rise  to  it : 
"  Pour  etre  convaincfi,"  says  this  distinguished 
physiologist,  "  qu'un  corps  plus  on  moins 
dur,  mais  flottant  dans  une  substance  gela- 
tineuse  recoit  la  plus  legere  commotion  ou 
mouvement  exterieur,  on  n'a  qu'a  remplir  un 
verre  de  gelce  de  corne  de  cerf,  ct  y  plonger 
quelque  corps,  on  sentira  aux  doigts  le  mouve- 
ment de  ce  corps  des  qu'on  remuera  le  verre, 
ou  qu'on  lui  donnera  un  petit  choc  avec  un 
doigt  de  l'autre  main.  Quand  on  enferme  dans 
une  petite  vessie  quelque  corps  dur,  le  moindre 
mouvement  de  la  vessie  fait  branler  ce  corps, 
qui  produit  une  sensation  tres  forte  sur  le  doigt 
qui  tient  la  vessie."  f 

Sir  A.  Carlisle  thinks  that  the  nature  of  this 
substance  has  reference  to  the  habits  of  the 
particular  class  of  fishes  in  which  it  exists. 
"  Fishes,"  he  says,  "  are  only  provided  with 
more  simple  organs  of  hearing,  ordained  to 
inform  them  of  collisions  among  rocks  and 
stones,  or  the  rushing  of  water  or  moving 
bodies  in  that  element :  and  since  the  collisions 
of  stones  or  of  water  are  only  variable  in  their 
magnitude  or  intensity,  fishes  are  provided 
with  these  dense  ossicles  to  repeat  the  sem- 
blable  acute  tones  of  similarly  dense  substances, 
such  as  rocks,  stones,  gravel,  &c."  Again, 
"  There  is  an  especial  sac  of  calcareous  pulp 
given  to  skates  and  some  other  cartilaginous 
fishes  in  the  place  of  the  dense  ossicles,  ap- 
parently intended  to  respond  to  the  movements 
of  sand  and  muddy  strata  on  which  they  are 
doomed  to  reside ;  and  it  is  remarkable  that  the 
sturgeon  has  its  auditory  ossicles  consisting 
partly  of  hard  substance  and  partly  of  calca- 
reous pulp."  % 

Weber  believes  that  the  otolithes  in  fishes 
supply  the  place  of  the  cochlea  which  is  want- 
ing in  these  animals:  the  auditory  nerves  being 
connected  with  them   receive  the  vibrations 

*  So  definite  does  the  form  of  these  otolithes 
appear  to  be  in  osseous  fishes,  that  Cuvier  says 
the  osseous  fishes  may  be  determined  by  their 
otolithes  as  well  as  by  any  other  character. 

t  Mem.  de  l'Acad.  des  Sciences,  an.  1779,  and 
quoted  in  Scarpa  De  auditu  et  olfactu,  p.  23. 

%  Quoted  from  a  Mss.  Essay  on  sound,  in  the 
Hunterian  Catalogue,  vol.  iii.  p.  193.  Miiller  calls 
the  otolithe  "  Eine  freier  solider  Schwingungen 
repcrcutirender  Kbrpcr." 


568 


HEARING. 


direct  from  them,  or  sometimes  the  otolithes 
are  so  placed  with  reference  to  the  expansion 
of  the  vestibular  nerve,  as  to  be  able  to  com- 
press it  against  the  cranium. 

But  in  man  and  those  animals  in  whom,  in 
addition  to  a  more  complicated  labyrinth,  there 
is  also  an  external  auditory  passage  and  tym- 
panum, it  would  appear  that  the  sonorous 
vibrations  are  conducted  in  two  ways ;  first, 
through  the  meatus  externus  and  tympanum 
to  the  vestibule  and  semicircular  canals ;  and, 
secondly,  through  the  bones  of  the  head  di- 
rectly to  the  auditory  nerve.  Sounds  pro- 
ceeding from  external  bodies,  as  Weber  ob- 
serves, are  conveyed  in  the  former  way ;  but 
the  oscillations  of  one's  own  voice,  although 
they  in  part  find  their  way  by  the  external  pas- 
sage, are  chiefly  conducted  by  the  cranial  bones; 
and,  as  Professor  VVheatstone  has  remarked, 
those  sounds  are  best  heard  which  are  articu- 
lated most  in  the  mouth,  and  with  that  cavity 
least  open,  as  e,  ou,  te,  kew.  Closing  both  ears 
by  firmly  pressing  the  hands  upon  them,  one's 
own  voice  is  not  heard  less  distinctly,  but  on 
the  contrary  more  loud  and  clear  than  when 
both  ears  are  left  open ;  and  if  only  one  ear  be 
closed,  the  voice  is  heard  more  distinctly  and 
louder  in  that  ear  than  in  the  open  one.* 

The  observations  and  experiments  of  Weber 
render  it  very  probable  that  the  cochlea  is  that 
part  of  the  labyrinth  which  is  more  particularly 
suited  to  appreciate  sounds  communicated 
through  the  solid  case  of  the  head,  or,  to  use 
his  words,  that  sounds  propagated  through  the 
bones  of  the  head  are  heard  specially  by  the 
cochlea,  but  that  sounds  conducted  through  the 
external  meatus  are  perceived  by  the  membra- 
nous vestibule  and  semicircular  canals  more 
easily  than  by  the  cochlea.  The  following  con- 
siderations favour  these  views. 

It  is  an  admitted  fact  in  acoustics  that 
sounds  are  most  perfectly  conducted  by  sub- 
stances of  uniform  elasticity,  and  that  when 
propagated  from  air  or  water  to  a  solid,  or 
from  a  solid  to  air  or  water,  they  are  conducted 
much  less  completely.  Now,  inasmuch  as  the 
cochlea  may  be  regarded  as  part  and  parcel  of 
the  cranial  bones,  the  sounds  which  are  pro- 
pagated by  these  bones  would  reach  the  nervous 
expansion  in  that  portion  of  the  labyrinth  by  the 
most  direct  route;  whereas,  to  affect  the  re- 
maining parts  of  the  labyrinth,  the  sound  must 
be  conducted  from  the  bone  through  the  peri- 
lymph to  the  membranous  vestibule  and  semi- 
circular canals.  Moreover,  when  it  is  con- 
sidered that  the  cochlear  nerves  are  disposed 
in  a  radiated  manner  in  the  lamina  spiralis, 
it  will  appear  evident  that  the  oscillations  pro- 
pagated to  the  petrous  portion  of  the  temporal 
bone  must  exert  a  direct  influence  on  the  coch- 
lear portion  of  the  auditory  nerve. 

One  or  two  experiments  with  the  tuning-fork 
show  not  only  that  the  cranial  bones  do  con- 
duct, but  also  that  sounds,  inaudible  or  im- 
perfectly audible  through  the  meatus  externus, 
may  be  distinctly  heard  when  the  sounding 

*  E.  H.  Weber  De  Auditu  in  Annotai.  Anatom. 
et  Physiolog.  Lips.  1834. 


body  is  brought  into  contact  with  a  bone  of  the 
cranium  or  face.  When  the  tuning-fork  is  put 
into  vibration  by  striking  it  against  any  solid 
body,  if  held  near  the  external  ear  its  vibrations 
are  heard  distinctly,  but  let  the  handle  be 
applied  to  the  teeth  or  to  the  superior  maxilla, 
and  the  sound  appears  much  louder ;  or  if  the 
fork  be  held  near  the  ear  until  the  sound  has 
almost  died  away,  and  then  its  handle  be  ap- 
plied to  the  superior  maxilla  or  the  teeth,  the 
sound  seems  greatly  to  revive  and  continues 
for  a  considerable  period,  the  handle  being 
kept  in  contact  with  the  bone. 

When  the  conducting  stem  of  the  sounding 
tuning  fork  is  placed  on  any  part  of  the  head, 
if  both  ears  be  closed  by  being  covered  with 
the  hands,  a  considerable  augmentation  of  the 
sound  will  be  observed.*  If  the  sounding- 
fork  be  kept  in  contact  with  the  head  for  a 
short  time,  both  ears  remaining  open,  and  then 
one  ear  be  closed,  the  sound  will  be  greatly 
augmented  in  the  closed  ear,  and  will  appear 
to  be  heard  exclusively  by  it.  This  experiment 
is  more  striking  if  the  stem  of  the  tuning-fork 
be  applied  to  the  mastoid  process  on  one  side  : 
when  both  ears  remain  open,  the  sound  seems 
to  be  heard  chiefly  by  the  ear  in  the  vicinity 
of  which  the  stem  is  placed,  but  when  the 
opposite  ear  is  closed,  it  appears  as  if  the 
sound  were  transferred  from  the  open  to  the 
closed  ear ;  and  if  the  ear  be  alternately 
opened  and  closed,  the  sound  will  alternately 
appear  to  be  transferred  from  the  one  to  the 
other.  Similar  phenomena  may  be  observed 
if  both  ears  are  closed  on  the  first  application 
of  the  tuning-fork.  The  sound  is  at  first  heard 
in  the  adjacent  ear,  and  either  remains  in  it 
or  is  transferred  to  the  opposite  one,  according 
as  the  former  remains  closed  or  is  opened. 
Mr.  Wheatstone  adds  that  if  the  meatus  and 
concha  of  one  ear  be  filled  with  water,  the 
sound  from  the  tuning-fork  will  be  referred  to 
the  cavity  containing  the  water  in  the  same  way 
as  when  it  contained  air  and  was  closed  by  the 
hand. 

These  phenomena  afford  obvious  examples 
of  the  communication  of  sound  through  the 
bones  of  the  head.  The  augmentation  of  the 
sound  in  the  closed  ear  appears  to  result,  as 
Mr.  Wheatstone  explains,f  from  the  recipro- 
cation of  the  vibrations  by  the  air  contained 
within  the  closed  cavity,  and  this  explanation 
is  confirmed  by  the  fact  that  when  the  meatus 
is  closed  by  a  fibrous  substance,  such  as  wool, 
no  increase  is  obtained. 

The  following  rationale  may  be  offered 
of  what  occurs  when  the  sound  from  the 
tuning-fork  is  communicated  to  a  closed 
ear,  in  accordance  with  the  views  of  Weber 
respecting  the  function  of  the  cochlea.  The 
vibrations  of  the  fork  are  propagated  by  the 
bones  of  the  head  to  the  cochlea,  the  fluid  of 
which  being  thus  thrown  into  vibration  causes 
the  membrane  of  the  fenestra  rotunda  to  vibrate, 

*  These  experiments  were  first  suggested  by 
Professor  Wheatstone. — See  his  experiments  on 
audition  in  the  Journal  of  the  Royal  Institution 
for  July  1827. 

t  Loc.  cit. 


HEARING. 


by  which  as  well  as  by  the  vibrations  of  the 
bones,  the  air  in  the  tympanum  is  made  to 
vibrate,  and  that  cavity  being  closed  the  sono- 
rous vibrations  are  reflected  from  its  walls  so  as 
to  give  rise  to  the  augmentation  of  the  sound. 

Autenrieth  and  Kemer  believed  the  cochlea 
to  be  that  part  of  the  auditory  apparatus  by 
which  we  perceive  what  the  French  call  the 
"  timbre"  of  sounds;  that  quality,  namely, 
which  depends  on  the  nature  of  the  material 
of  which  the  sounding  body  is  constituted, 
as  well  as  on  its  form  and  size,  and  in  some 
degree   on   the  manner  in  which  sound  is 
elicited  from  it;  and  they  considered  it  the 
office  of  the  vestibule  to  convey  to  the  sen- 
sorium  the  pitch  and  strength  of  sounds.  Their 
opinion  as  to  the  function  of  the  cochlea  was 
founded  on  some  experiments  as  to  the  extent 
to  which  ceitain  of  the  lower  animals  were 
affected  by  particular  instruments  of  music : 
the  results  obtained  from  these  experiments, 
when  taken    in  connexion  with   certain  dif- 
ferences in  the  form  and  other  characteristics 
of  the  cochlea  in  those  animals,   led  these 
authors  to  the  conclusion  that   "  those  ani- 
mals alone  seemed  to  perceive  a  difference 
of  the  '  timbre '  of  sounds  of  pretty  uniform 
pitch  and  loudness,  in  whom  the  cochlea  was 
very  long  and  projected  considerably  into  the 
cavity  of  the  tympanum,  and  was  not  much 
concealed  by  the  surrounding  bony  substance. 
Thus  it  appeared  that  a  dog  (the  cochlea  of 
dogs  being  longer  than  that  of  cats),  upon 
hearing  a  certain  note  of  the  clarionet,  set  up 
a  howl,  but  seemed  in  no  way  affected  at 
hearing  the  same  note  from  the  flute  or  violin  ; 
but  the  cat  continued  undisturbed,  although  a 
variety  of  instruments  was  sounded   in  her 
hearing.     A  rabbit  (in  which  the  cochlea  is 
prominent)  ran  away  at  the  note  C  elicited  from 
a  glass  tumbler  or  from  a  string,  but  remained 
still  when  the  same  note  was  sounded  even 
more  loudly  by  the  flute."*    But  it  is  abun- 
dantly evident  that  these  experiments  do  not 
fairly  lead  to  the  conclusion  which  these  phy- 
siologists endeavoured   to   establish ;   for,  as 
Weber  has  remarked,  it  is  one  thing  to  be  dis- 
agreeably affected  by  the  peculiar  tone  of  a 
given  note  in  an  instrument  of  music,  and 
another  thing  to  distinguish  the  timbre  of  the 
notes  of  different  musical  instruments.  As 
well  might  we  conclude  that  dogs  excel  in  the 
power  of  distinguishing  scents  and  savours, 
because  the  smell  and  taste  of  spirits  of  wine 
seem  to  be  peculiarly  disagreeable  to  them, 
and  they  reject  instantly,   although  hungry, 
any  food  offered  to  them  with  which  that  has 
been  mixed. 

It  seems  evident  that  the  cochlea  is  an  in- 
dication of  a  very  advanced  condition  of  the 
organ  of  hearing  ;  beyond  this  we  can  arrive  at 
no  definite  conclusion  in  the  present  state  of 

*  See  these  experiments  quoted  at  greater  length 
in  Weber's  paper  before  referred  to.  Autenrieth's 
paper  is  to  be  found  in  Reil's  and  Autenrieth's 
Archiv.  fur  die  Physiologie,  B.  ix.  1809 ;  and 
contains  much  valuable  and  highly  interesting 
matter  relative  to  all  the  parts  of  the  organ  of 
hearing  in  several  of  the  Mammalia. 


our  knowledge,  unless  indeed  we  admit  the 
very  general  one  of  Weber,  that  it  is  the  pri- 
mary seat  of  those  auditory  impressions  which 
are  conveyed  through  the  vibrations  of  the 
cranial  bones.  But  this  view,  however  pro- 
bable, and  supported  by  much  sound  reasoning, 
throws  no  light  on  the  object  of  the  peculiar 
form  and  mechanism  of  the  cochlea.  We 
must  not  omit  to  notice  that  a  portion  of  the 
vestibule  is  regarded  by  Weber  as  performing 
a  similar  function  to  that  of  the  cochlea,  and 
on  similar  grounds.  That  portion  which  is 
known  under  the  name  of  the  sacculus  is  so 
adherent  to  the  bony  wall  of  the  vestibule, 
corresponding  to  ihejbvea hemispheric  a,  accord- 
ing to  Scarpa,  that  it  cannot  be  separated 
without  laceration,  and  consequently  it  seems  to 
be  better  adapted  to  receive  the  sonorous  vibra- 
tions which  are  conveyed  by  the  cranial  bones. 

The  remaining  parts  of  the  labyrinth,  namely, 
the  three  semicircular  canals  and  the  common 
sinus,  are  most  affected  by  those  sounds  which 
are  conveyed  through  the  external  meatus  :  it 
seems  evident  at  least  that  they  must  be  more 
affected  than  the  cochlea  from  the  connexion 
between  the  membrana  tympani  and  fenestra 
ovalis  through  the  chain  of  tympanic  ossi- 
cles, by  which  that  membrane  is  brought 
into  direct  communication  with  the  perilymph 
surrounding  the  membranous  labyrinth.  On 
the  other  hand  these  parts  are  badly  adapted 
to  receive  the  impression  of  vibrations  direct 
from  the  cranial  bones,  being  separated  from 
the  corresponding  osseous  parts  by  the  peri 
lymph,  and  that  part  of  the  auditory  nerve 
which  is  distributed  to  them,  having  no  con- 
nexion with  the  bone.  An  experiment  of 
Weber  illustrates  the  relation  of  the  perilymph 
to  the  membranous  labyrinth,  and  shows  that 
an  impulse  upon  the  membrana  tympani  is 
capable  of  affecting  it.  In  some  birds,  the 
falcon  for  example,  the  semicircular  canals  are 
so  large,  that  the  membranous  canals  may  be 
easily  seen.  If  in  such  a  bird  one  osseous 
semicircular  canal  be  opened  by  a  small  open- 
ing, care  being  taken  not  to  injure  the  mem- 
branous canal,  and  then  we  press  the  mem- 
brane of  the  tympanum  inwards,  at  each  com 
pression  we  observe  the  water  contained  in  the 
bony  canal  to  flow  out  with  a  jerk.  He  there- 
fore concludes  that  the  sonorous  undulations 
conveyed  by  the  cranial  bones  are  communi- 
cated more  immediately  to  the  nerve  of  the 
cochlea,  but  those  conveyed  by  the  external 
meatus  to  the  nerve  of  the  vestibule. 

The  semicircular  canals  are  remarkable  for 
the  constancy  of  their  number,  and  of  their  re- 
lative position  with  respect  to  each  other,  in  all 
animals  in  whom  they  are  found.  They  exist 
in  almost  all  fishes,  and  in  all  the  other  vertebrate 
classes,  and  in  these  they  are  never  less  than 
three  in  number,  two  of  which  are  always 
placed  vertically  and  one  horizontally.  The 
opinion  that  the  arrangement  of  these  canals 
has  reference  to  conveying  the  sensation  of  the 
direction  of  sounds,  I  find  expressed  by  Au- 
tenrieth and  Kerner  in  the  paper  already  re- 
ferred to.  "In  no  animal,"  they  say,  "are  these 
canals  ever  more  or  fewer  on  each  side  than 


570 


HEARING. 


three,  which  are  so  situated  that  they  correspond 
to  the  three  dimensions  of  a  cube,  its  length, 
breadth,  and  depth,  and  that  every  sound  ar- 
riving in  one  of  these  three  directions  will 
always  strike  one  canal  at  right  angles  to  its 
axis,  and  another  in  its  length.  The  position 
of  these  canals  is  likewise  such,  that  the  cor- 
responding canals  of  opposite  sides  cannot  be 
parallel,  and  that  therefore  any  sound  which 
strikes  the  head  in  any  given  direction  affects 
the  semicircular  canal  of  one  side  much  more 
than  the  corresponding  one  of  the  opposite 
side,  whereby  it  may  be  determined  whether 
the  sound  coming  in  a  straight  line  (from  west 
to  east  for  example,)  has  really  moved  from 
west  to  east,  or  from  east  to  west."*  They 
state  that  in  animals  in  whom  the  semicircular 
canals  are  highly  developed,  the  power  of  dis- 
tinguishing the  direction  of  sounds  is  marked 
to  a  proportionate  degree.  Thus  in  the  mole, 
the  development  of  these  canals  is  very  con- 
siderable, and  from  a  simple  experiment  it 
appears  that  this  animal  readily  distinguishes 
the  direction  of  sounds.  A  mole  was  intro- 
duced into  a  wide  but  flat  vessel  filled  with 
earth,  in  which  he  was  allowed  to  burrow, 
and  it  was  found  that  the  mole  could  be  made 
to  move  about  by  sounding  an  instrument  out- 
side the  vessel ;  if  the  instrument  were  sounded 
on  one  side,  the  animal  would  always  imme- 
diately turn  to  the  other,  f  The  fox  seemed  to 
distinguish  the  direction  of  sounds  better  than 
cats  :  if  at  the  same  time,  and  at  opposite  sides, 
the  high  tones  of  a  little  bell  and  the  deep 
tones  of  a  bass  viol  were  sounded,  the  fox 
always  turned  to  the  side  whence  the  high 
notes  came.  Cats  seem  to  be  sensible  of  the 
direction  of  high  notes  only.  When  upon  a 
violin,  or  a  flageolet,  or  upon  a  glass  goblet 
containing  water,  high  notes  were  sounded, 
the  cats  always  turned  towards  the  place 
whence  the  sound  came,  even  although  the  in- 
strument was  concealed  from  them  :  on  the 
other  hand,  when  a  person  seated  on  the  ground 
sounded  the  low  notes  of  a  bass  viol  before  several 
cats  in  a  garden,  they  seemed  to  seek  in  all  direc- 
tions for  the  place  of  the  sounding  body,  without 
nitting  upon  the  right  one.  The  cow,  the 
horse,  the  pig,  and  the  rabbit  seemed  to  mani- 
fest particularly  little  sensibility  to  the  direction 
of  sounds.  The  dog  appears  to  have  less  power 
to  distinguish  the  direction  of  sound  than  man; 
his  smell  seems  to  assist  him,  and  it  is  well 
known  that  when  a  dog  is  called  by  his  master, 
he  commonly  runs  backwards  and  forwards 
for  some  time  before  he  finds  out  the  right 
direction.  The  human  semicircular  canals 
greatly  exceed  in  width  all  others  examined  by 
Autenrieth  and  Kerner,  but  this  excess  is  more 
as  regards  the  canals  properly  so  called,  but 
does  not  apply  to  the  ampullae.    Scarpa  had 

*  Op.  cit.  p.  363. 

t  This  experiment,  however,  was  repeated  by 
Esser,  who  assures  us  that  the  direction  of  the 
movements  of  the  mole  was  not  influenced  by  the 
direction  of  the  tones  of  the  instrument.  Kastner's 
Archiv.  fur  die  gesammte  Naturlehre,  B.  12,  s.,56. 
quoted  in  Treviranus,  Ergchein.  und  Gesetze  des 
Organischen  Lebens. 


already  remarked,  that  although  the  canals  of 
oxen  and  horses  were  narrower  than  those  of 
man,  the  ampullae  were  scarcely  at  all  smaller 
than  in  the  human  subject.  These  observers 
further  remarked,  in  many  animals  they  ex- 
amined, an  inverse  ratio  between  the  width 
of  the  ampulla  and  that  of  the  canals ;  that 
the  former  were  wider  in  proportion  as  the 
latter  were  narrow.  In  fine,  they  conclude 
that  the  wider  the  semicircular  canals,  the  size 
of  the  animal  being  taken  into  account,  the 
greater  is  the  power  of  distinguishing  the  direc- 
tion of  sound.  Of  the  lower  animals,  the 
first  in  order  as  regards  this  power  is  the 
hedge-hog,  which,  after  the  human  subject, 
has,  relatively  to  its  size,  the  widest  semicircu- 
lar canals ;  we  may  form  some  idea  of  the 
width  of  these  canals  from  the  fact  that  in 
their  centre  they  are  nearly  as  wide  as  the 
semicircular  canals  of  the  pig,  which  is  so 
very  much  larger  an  animal.  Next  to  the 
hedge-hog  stands  the  mole,  whose  canals  are, 
proportionally  to  the  size  of  the  animal,  both 
remarkably  wide  and  long ;  they  are  peculiar 
also  as  projecting  free  (visible  without  any  prepa- 
tion)  into  the  cavity  of  the  cranium.  The 
mouse  and  the  bat  come  next,  then  the  fox  and 
the  dog,*  the  rabbit,  the  cat,  the  pig,  the  cow, 
the  horse,  and  lastly  the  sheep. 

Professor  Wheatstone  advocates  the  theory 
that  our  notions  of  audible  direction  depend 
upon  the  excitation  of  those  portions  of  the 
auditory  nerve  which  belong  to  the  semi- 
circular canals.  He  conceives  that  we  dis- 
tinguish best  the  direction  of  those  sounds 
which  are  sufficiently  intense  to  affect  the  bones 
of  the  head,  and  that  it  is  from  the  portion 
which  is  transmitted  through  those  bones  that 
our  perception  of  the  direction  is  obtained. 
Thus,  we  always  find  it  difficult  to  tell  by  the 
ear  the  position  whence  the  feeble  tones  of  the 
(Eolian  harp  proceed.  The  three  semicircular 
canals,  then,  being  situated  in  planes  at  right 
angles  with  each  other,  are  affected  by  the 
sound  transmitted  through  the  bones  of  the 
head  with  different  degrees  of  intensity  accord- 
ing to  the  direction  in  which  the  sound  is  trans- 
mitted ;  for  instance,  if  the  sound  be  trans- 
mitted in  the  plane  of  any  one  canal,  the  ner- 
vous matter  in  that  canal  will  be  more  strongly 
acted  on  than  that  in  either  of  the  other  two  ; 
or  if  it  be  transmitted  in  the  plane  intermediate 
between  the  planes  of  this  canal  and  the  ad- 
jacent one,  the  relative  intensity  with  which 
those  two  canals  will  be  affected  will  depend 
upon  the  direction  of  the  intermediate  plane. 
The  direction  suggested  to  the  mind  will  cor- 
respond with  the  position  of  the  canal  upon 
which  the  strongest  impression  has  been  made.-t- 

*  The  width  of  the  canals  in  dogs  was  found  to 
vary  in  the  different  races.  Autenrieth  and  Kerner, 
loc.  cit. 

f  Dr.  Young  thought  that  the  semicircular  canals 
seemed  very  capable  of  assisting  in  the  estimation 
of  the  acuteness  or  pitch  of  a  sound  by  receiving 
its  impression  at  their  opposite  ends,  and  occa- 
sioning a  recurrence  of  similar  effects  at  different 
points  of  their  length,  according  to  the  different 
character  of  the  sound ;  while  the  greater  or  less 


HEARING. 


571 


No  conclusions  can  be  derived  from  the 
experiments  of  Flourens  with  respect  to  the 
functions  of  the  several  parts  of  the  labyrinth. 
The  effects  of  disease  had  already  sufficiently 
indicated  the  relative  importance  of  the  dif- 
ferent parts  of  the  ear,  and  even  to  a  certain 
extent  of  those  of  the  labyrinth.  Thus  we 
knew  that  stoppage  or  destruction  of  the  ex- 
ternal parts  does  no  more  than  impair  the  sense 
of  hearing,  and  that  so  long  as  the  labyrinth 
remains  perfect,  or  at  least  the  vestibule,  the 
sense  is  not  destroyed.  Sound  may  be  con- 
veyed to  the  auditory  nerve  through  the  bones 
of  the  head,  as  may  be  proved  by  the  sen- 
sation of  sound  produced  by  the  application 
of  a  tuning-fork  in  vibration  to  the  teeth  or 
to  some  one  of  the  cranial  bones.  By  a  parity 
of  reasoning,  Flourens  having  successively  de- 
stroyed the  several  parts  of  the  ear  in  pigeons, 
inferred  that  the  nervous  expansion  in  the  ves- 
tibule was  the  part  of  the  organ  most  essential 
to  audition  :  "  that  in  strictness,  it  is  the  only 
indispensable  part,  for  all  the  others  may  be 
removed;  yet  if  this  continue,  audition  is  not 
destroyed."  Partial  destruction  of  the  nervous 
expansion  in  the  vestibule  only  partially  destroys 
the  sense,  and  complete  destruction  of  this  ex- 
pansion involves  total  deafness.  The  vestibule 
may  be  laid  open  without  any  very  considerable 
alteration  in  the  sense ;  but  rupture  of  the  semi- 
circular canals  rendered  the  hearing  confused 
and  painful,  and  was  moreover  accompanied 
with  a  quick  and  violent  tossing  of  the  head.* 

One  can  scarcely  imagine  vivisections  less 
likely  to  lead  to  useful  results  than  those 
which  involve  the  exposure  of  the  deep-seated 
internal  parts  of  the  ear,  a  dissection  which 
even  on  the  dead  subject  demands  no  ordinary 
skill ;  nor  can  we  refrain  from  expressing  our 
opinion  that  had  M.  Flourens  never  attempted 
these  experiments,  physiology  would  have  been 
none  the  worse,  and  our  respect  for  his  hu- 
manity would  have  been  all  the  greater. 

II.  Of  the  accessory  parts  of  the  organ. — 
We  shall  consider  in  succession  the  parts  which 
the  external  ear — the  tympanum,  its  membrane 
and  ossicles,  and  the  Eustachian  tube,  play  in 
the  process  of  audition. 

The  external  ear  may  be  regarded  as  consist- 
ing of  two  parts,  the  auricle  and  the  meatus 
auditorius  externus.  The  complete  develope- 
ment  of  the  former  is  found  only  in  Mammi- 
ferous  animals,  and  exists  pretty  generally 
throughout  the  class  ;  with,  however,  consider- 
able diversity  of  form,  varying  from  an  almost 
flat  cartilaginous  lamella,  scarcely  at  all  under 
the  influence  of  its  muscles,  to  an  elongated 
funnel-shaped  ear-trumpet,  very  moveable  and 
completely  at  the  command  of  numerous  large 
muscles.  Man  and  the  Quadrumana  are  at  one 
extremity  of  this  scale  ;  the  Solipeds,  Rumi- 
nants, and  Cheiroptera  at  the  other.  Some, 

pressure  of  the  stapes  must  serve  to  moderate  the 
tension  of  the  fluid  within  the  vestibule,  which 
serves  to  convey  the  impression.  The  cochlea  seems 
to  be  pretty  evidently  a  micrometer  of  sound. — See 
Med.  Lit.  p.  98. 

*  Conditions  do  l'Audition  in  Experiences  sur  lc 
Systeme  nervcux,  p.  49.  Par.  1825. 


however,  are  devoid  of  the  auricle,  as  the  mole, 
the  zemni-rat,  the  mole-rat,  the  seal,  the  walrus, 
&c.  It  is  said  that  those  animals  which  are 
remarkable  for  the  large  developement  of  the 
auricle  are  almost  all  timid  or  nocturnal,  and 
consequently  require  an  acute  sense  of  hearing. 

That  the  auricle  performs  the  office  of  an 
acoustic  instrument  to  collect  and  reinforce  the 
sounds  which  fall  upon  it,  cannot  be  doubted 
in  those  cases  in  which  it  is  large  and  fully 
developed,  as  in  the  horse,  ass,  &c.  Here, 
indeed,  we  see  that  the  animal  employs  it  as 
we  might  expect  such  an  instrument  would  be 
used ;  the  open  part  is  directed  towards  the 
quarter  whence  the  sound  comes,  and  continues 
so  directed  as  long  as  the  animal  appears  to  listen. 
So  far,  however,  from  this  part  being  mainly  the 
instrument  for  enabling  the  animal  to  judge  of 
the  direction  of  sound,  it  appears  to  me  that 
it  cannot  be  applied  to  its  full  use  until  the 
direction  of  the  sound  has  been  in  some  mea- 
sure determined  ;  until  the  hearing-trumpet  has 
been  favourably  placed  with  respect  to  the 
quarter  whence  the  sound  emanates,  its  value 
is  not  fully  experienced.  If  we  watch  the 
movements  of  the  auricle  of  a  horse,  we  shall 
see  that  he  uses  it  altogether  for  concentrating 
sounds  from  particular  quarters:  when  he  moves 
it  about  quickly,  it  often  seems  as  if  he  were 
feeling  for  sounds  coming  from  certain  direc- 
tions, having  already  acquired  a  tolerable 
notion,  if  I  may  so  speak,  as  to  what  those 
directions  are.  Treviranus,*  however,  thinks 
that  the  reinforcement  of  the  sound  is  not  its 
principal  use :  "  to  what  end,"  he  asks,  "  have 
its  various  eminences  and  depressions  been 
formed,  if  it  have  no  other  use  than  this,  and 
why  are  these  particularly  developed  in  the 
human  ear,  which  can  have  little  or  no  in- 
fluence as  an  ear-trumpet  in  increasing  the 
influence  of  sounds?"  He  supposes  that  in 
the  lower  animals,  but  especially  in  man,  the 
auricle  serves  more  for  forming  a  judgment 
respecting  the  direction  of  sounds  than  for 
assisting  in  hearing.  We  cannot  understand  in 
what  way  the  fixed  auricle  of  man  can  aid  for 
this  purpose,  being  almost  immoveable,  and  in- 
deed altogether  so  for  the  purposes  of  collect- 
ing sonorous  undulations  from  different  quar- 
ters; nor  indeed  does  it  appear  that  the  opinion 
in  question  of  Treviranus  is  any  thing  more 
than  a  mere  hypothesis.  A  remark  of  Mr. 
Gough,  the  author  of  a  highly  interesting 
paper  in  the  Manchester  Memoirs  "  on  the 
method  of  judging  by  the  ear  of  the  position 
of  sonorous  bodies,"  offers  a  strong  argument 
against  this  notion.  He  observes  that  what- 
ever may  be  the  direction  of  a  sound  in  the 
open  air,  as  soon  as  it  enters  the  auditory  pas- 
sage, it  is  compelled  to  follow  the  course  of 
that  duct  until  it  reaches  the  apparatus  in  which 
the  sense  of  hearing  resides.f 

The  experimental  researches  of  Savart  throw 
some  light  upon  the  function  of  this  part  of 
the  auditory  apparatus.}    These  experiments 

*  Loc.  cit.  B.  ii.  p.  137. 

t  Manchester  Memoirs,  New  Series,  vol.  v. 

X  Majeudie's  Journal  dc  Physiologic,  torn.  iv. 


572 


HEARING. 


were  suggested  by  the  result  of  several  ob- 
servations which  he  made  upon  the  communi- 
cation of  vibrations  through  the  air  from  a 
vibrating  body  to  one  placed  even  at  a  great 
distance  from  it,  and  susceptible  of  under- 
going vibrations.  The  effect  is  best  seen  by 
using  a  thin  membrane,  such  as  very  fine  paper, 
carefully  stretched  in  a  horizontal  position  over 
the  mouth  of  a  glass,  or  of  a  small  delft  basin  : 
a  thin  layer  of  sand  is  spread  on  this,  and  a 
glass  thrown  into  vibration  by  a  violin  bow 
is  held  at  a  little  distance  from  it ;  that  the 
paper  immediately  begins  to  vibrate  is  shewn 
by  the  motions  excited  in  the  sand,  the  par- 
ticles of  which  arrange  themselves  into  figures, 
which  are  sometimes  perfectly  regular,  and 
which  form  with  so  much  rapidity  that  the  eye 
can  scarcely  follow  "  the  circumstances  which 
accompany  the  transformation  of  the  thin  layer 
of  sand  into  a  greater  or  less  number  of  lines 
of  repose." 

By  a  series  of  experiments  to  be  hereafter 
detailed,  Savart  showed  that  the  tympanic 
membrane  is  capable  of  being  thrown  into 
vibrations  by  the  sonorous  impulses  from  a 
vibrating  body  communicated  to  it  by  the  in- 
terposed air  How  far  the  external  ear  and 
auditory  canal  serve  to  increase  these  vibrations 
of  the  tympanic  membrane,  he  sought  to  ascer- 
tain by  the  following  experiments.  He  formed 
a  conical  tube  of  pasteboard,  with  a  very  wide 
mouth  at  its  base,  the  opening  at  the  smaller 
end  being  closed  by  a  thin  paper  stretched 
over  it  and  glued  to  the  margins  of  the  open- 
ing. This  tube  is  placed  resting  on  its  base, 
the  membrane  being  upwards  and  per- 
fectly horizontal,  so  that  a  layer  of  sand  may 
be  spread  over  it.  When  a  vibrating  glass  is 
brought  near  and  parallel  to  the  upper  surface 
of  this  membrane,  it  immediately  begins  to 
vibrate,  and  the  grains  of  sand  are  tossed  about 
but  raised  but  very  slightly  from  the  surface. 
If,  however,  the  vibrating  glass  be  placed  near 
the  base  or  the  wide  and  open  extremity  of  the 
tube,  the  vibrations  of  the  membrane  will  be 
found  to  be  much  more  manifest,  and  the  ex- 
cursions of  the  grains  of  sand  so  considerable, 
that  they  are  often  raised  to  a  height  of  three 
or  four  centimetres  ;  so  that  there  is  a  manifest 
difference  in  the  influence  produced  upon  the 
membrane  by  the  sonorous  undulations  excited 
in  the  air  according  as  they  impinge  upon  the 
external  surface  of  the  membrane  or  upon  that 
which  is  turned  towards  the  interior  of  the  tube. 
This  phenomenon,  Savart  adds,  may  depend 
upon  two  causes,  namely,  upon  the  concen- 
tration of  the  sonorous  undulations  by  the  tube, 
or  upon  the  communication  of  motion  to  the 
parietes  of  the  tube,  which  again  would  com- 
municate it  to  the  membrane.  With  a  view 
to  ascertain  which  of  these  causes  was  the 
effective  one,  a  second  conical  tube,  open  at 
both  ends,  was  held  with  its  narrow  extremity 
a  little  above  and  corresponding  to  the  narrow 
extremity  of  the  former  one,  but  so  that  there 
was  no  contact  between  them.  If  now  the 
glass  is  made  to  vibrate  successively  at  the 
large  orifices  of  the  two  tubes,  it  will  be  found 
that  when  placed  at  the  orifice  of  the  tube  to 


which  the  membrane  is  attached,  the  oscil- 
lations of  that  membrane  are  considerably 
greater  than  when  the  aerial  undulations  reach 
it  through  the  other  tube.  Whence  it  may  be 
inferred  that  in  all  probability  the  external  ear 
and  auditory  canal  have,  besides  any  influence 
they  may  exert  in  modifying  the  movements 
of  the  particles  of  the  air,  the  additional  function 
of  presenting  a  large  surface  to  the  aerial  un- 
dulations, consequently  to  enter  into  vibration 
under  their  influence,  and  thus  to  contribute 
to  increase  the  excursions  of  the  vibrating  pd^ts 
of  the  membrane  with  which  they  are  imme- 
diately in  contact;  the  auricle,  by  the  variety 
of  the  direction  and  the  inclination  of  its  sur- 
faces to  one  another,  can  always  present  to  the 
air  a  certain  number  of  parts,  whose  direction 
is  normal  (at  right  angles  with)  to  that  of  the 
molecular  movement  of  that  fluid. 

We  get  a  general  notion  of  the  value  of  this 
external  part  of  the  auditory  apparatus  in  col- 
lecting and  directing  the  sonorous  undulations, 
from  the  assistance  often  derived  in  hearing 
from  increasing  the  concavity  of  the  external 
ear  by  placing  the  hand  behind  it,  so  as  to 
draw  it  forward  and  shorten  it  by  pressure  at 
its  upper  and  lower  part;  by  the  dulness  of 
hearing  which  it  is  said  follows  the  loss  of  the 
auricle,  and  from  the  fact,  so  stated,  that  the 
seal  and  walrus  are  extremely  dull  of  hearing. 
As  regards  the  loss  of  the  auricle,  it  is  said 
by  Kerner  that  this  loss  is  followed  by  the 
greatest  dulness  of  hearing  in  those  animals 
in  whom  the  osseous  meatus  is  wanting.  In  a 
cat,  from  whom  the  right  ear  was  cut  close  to 
the  skull,  after  the  wound  had  healed  without 
any  stoppage  of  the  meatus,  there  was  a  re- 
markable disposition  always  to  keep  its  head 
turned  so  as  to  be  ready  to  receive  sounds  with 
the  left  ear,  and  this  continued  even  after  the 
tympanic  membrane  of  the  opposite  side  had 
been  frequently  perforated,  that  of  the  right  side 
remaining  whole ;  and  when  the  left  ear  was 
stopped  (although  the  right  tympanic  mem- 
brane was  sound,  and  the  only  injury  on  that 
side  was  the  removal  of  the  auricle,)  a  total  deaf- 
ness was  manifested  except  to  the  loudest  and 
clearest  sounds. 

The  tympanum  and  its  contents. — We  have 
already  stated  that  Savart  had  demonstrated 
that  the  membrana  tympani  is  thrown  into 
vibrations  by  undulations  of  the  air  excited  by 
a  sonorous  body.  This  he  demonstrated  ex- 
perimentally upon  the  membrana  tympani 
itself.  The  temporal  bone  having  been  sepa- 
rated, he  sawed  away  the  osseous  meatus  so 
as  to  expose  the  membrane  on  a  level  with 
the  rest  of  the  bone,  and  when  it  was  suf- 
ficiently dry,  he  covered  it  with  a  thin  layer 
of  sand.  A  vibrating  glass  held  parallel  and 
very  near  to  the  surface  of  the  membrane 
occasioned  a  slight  movement  of  the  grains  of 
sand ;  but  owing  to  the  slight  extent  and  the 
shape  of  the  membrane,  it  was  impossible  to 
determine  the  existence  of  any  nodal  line. 
In  a  second  experiment,  the  cavity  of  the  tym- 
panum was  opened,  so  as  to  expose  the  ossi- 
cles of  the  ear  and  their  muscles ;  and  it  was 
observed  that  when  the  internus  mallei  muscle 


HEARING. 


573 


acted  and  rendered  the  membrane  tense,  it  was 
much  more  difficult  to  produce  manifest  move- 
ments in  the  grains  of  sand ;  thus  affording 
much  reason  to  suppose  the  tensor  tympani 
muscle  is  analogous  in  its  use  to  the  iris,  and 
destined  to  preserve  the  organ  from  too  strong 
impressions.  This  experiment  can  be  best  tried 
on  the  membrana  tympani  of  the  calf. 

In  imitation  of  the  mechanism  by  which  the 
tension  of  the  membrana  tympani  is  effected, 
and  with  a  view  to  determine  more  decisively 
the  effects  produced  by  variation  of  the  tension 
of  that  membrane,  Savart  constructed  a  conical 
tube  (fig.  262),  with  its 
apex  truncated  and  co-  Fig.  262. 

vered  by  a  layer  of  very  m  I 

thin    paper  {rri),  which  ( 
was  glued  to  the  edge  of         /  ^~J~~Z\f 
the  opening.     A   little         /  \ 
wooden  lever  (I  I),  intro-       /  \ 
duced  through  an  open-      /  \ 

ing  in  the  side  of  the    /..-  -A 

tube,  and  resting  on  the   L,  A 

lower  margin    of    this  \  

opening  (c)  as  a  fulcrum, 

was  used  to  vary  the  tension  of  the  membrane, 
one  of  its  extremities  being  applied  to  the 
under  surface  of  the  membrane.  It  is  evident 
that,  by  depressing  the  extremity  of  the  lever 
that  was  external  to  the  tube,  the  inner  one 
would  be  raised,  and  thus  the  membrane 
stretched  to  a  greater  or  less  degree  according 
to  the  force  used  ;  on  the  other  hand,  by  ele- 
vating the  outer  extremity,  the  inner  one  was 
separated  from  the  membrane,  which  was  ac- 
cordingly restored  to  its  original  tension.  This 
little  lever  was  employed  in  imitation  of  the 
handle  of  the  malleus,  which  under  the  in- 
fluence of  its  muscles  causes  the  variation  in 
the  tension  of  the  membrana  tympani.  The 
artificial  tympanic  membrane  then  having  been 
covered  with  a  layer  of  sand,  it  was  found  that, 
under  the  influence  of  a  vibrating  glass,  used 
as  in  the  former  experiments,  a  manifest  dif- 
ference was  produced  in  the  movements  of  the 
grains  of  sand,  by  increasing  the  tension  of  the 
paper;  the  greater  the  tension,  the  less  the 
height  to  which  the  grains  of  sand  were  raised  ; 
and  these  movements  were  most  extensive 
when  the  lever  was  withdrawn  from  contact, 
and  the  membrane  left  to  itself. 

From  these  experiments  Savart  concludes 
that  the  membrana  tympani  may  be  considered 
as  a  body  thrown  into  vibration  by  the  air, 
and  always  executing  vibrations  equal  in  num- 
ber to  those  of  the  sonorous  body  which  gave 
rise  to  the  oscillations  of  the  air.  But  what  is 
the  condition  of  the  ossicles  of  the  tympanum 
whilst  the  membrane  is  thus  in  vibration?  The 
result  of  the  following  experiment  affords  a 
clue  to  the  answer  of  this  question.  To  a 
membrane  stretched  over  a  vessel,  as  in  fig. 
263,  a  piece  of  wood  (a  6)  uniform  in  thick- 
ness is  attached,  so  that  the  adherent  part  shall 
extend  from  the  circumference  to  the  centre  of 
the  membrane,  while  the  free  portion  may 
project  beyond  the  circumference.  When 
a  vibrating  glass  is  brought  near  this  mem- 
brane, very  regular  figures  are  produced,  which 


Fig.  263. 


however  are  modified  by  the  presence  of  the 
piece  of  wood,  and  the  vibrations  of  the  mem- 
brane are  communicated  to  the  piece  of  wood, 
on  which  likewise  regular  figures  may  be  pro- 
duced. The  more  extensive  the  membrane,  the 
longer  and  thicker  may  be  the  piece  of  wood 
in  which  it  can  excite  oscillations,  and  Savart 
states  that,  with  membranes  of  a  considerable 
diameter,  he  has  produced  regular  vibrations 
in  rods  of  glass  of  large  dimensions.  The 
oscillations  of  the  piece  of  wood  are  much 
more  distinct  when  the  adherent  portion  is 
thinned  down,  as  in  c  d,  jig.  264,  by  which  it 


Fig.  264. 


seems,  as  it  were,  more  completely  identified 
with  the  membrane,  and  consequently  the 
oscillations  of  this  latter  are  communicated  di- 
rectly to  the  thinned  portion  of  the  wood,  and 
thence  extended  to  the  thick  portion  a :  sand 
spread  upon  a  will  exhibit  active  movements, 
and  will  produce  very  distinct  nodal  lines.  Thus 
it  may  be  inferred  that  the  malleus  participates 
in  the  oscillations  of  the  tympanic  membrane ; 
and  these  vibrations  are  propagated  to  the  incus 
and  stapes,  and  thus  to  the  membrane  of  the 
fenestra  ovalis.  The  chain  of  ossicles  then  evi- 
dently performs  the  office  of  a  conductor  of 
oscillations  from  the  membrana  tympani  to  the 
membrane  of  the  fenestra  ovalis ;  but  the  mal- 
leus likewise  has  the  important  function  under 
the  influence  of  its  muscles  of  regulating  the 
tension  of  the  tympanic  membrane ;  and  to 
allow  of  the  changes  in  the  position  of  this 
bone  necessary  for  that  purpose,  we  find  it 
articulated  with  the  incus  by  a  distinct  di- 
arthrodial  joint,  and  between  this  latter  bone 
again  and  the  stapes  there  exists  another  and 
a  similar  joint.  This  mobility  then  of  the 
chain  of  bones,  and  the  muscular  apparatus 
of  the  malleus  and  stapes  are  totally  irrespec- 
tive of  the  conducting  office  of  the  bones,  but 
have  reference  to  the  regulation  of  the  tension 
of  the  membrane  of  the  tympanum  as  well  as 
of  that  of  the  fenestra  ovalis.* 

We  have  already  seen  how  the  muscle  of 

*  The  experiments  of  Savart  above  detailed  have 
been  several  times  carefully  repeated  by  me  with 
results  precisely  similar, 


574 


HEARING. 


the  malleus  regulates  the  membrana  tympani, 
increases  its  tension,  and  thus  limits  the  extent 
of  the  excursions  of  its  vibrations.  The  con- 
traction of  the  stapedius  muscle  causes  the 
base  of  the  stapes  to  compress  the  membrane 
of  the  fenestra  ovalis  to  a  greater  or  less  extent, 
so  that  the  degree  of  tension  of  that  membrane 
depends  on  the  condition  of  this  muscle. 
Compression  exerted  upon  the  membrane  of 
the  fenestra  ovalis  extends  to  the  perilymph 
and  through  it  is  propagated  to  the  membrane 
of  the  fenestra  rotunda,  and  in  this  way  the 
same  apparatus  which  regulates  the  tension  of 
the  membrane  of  the  fenestra  ovalis  performs 
that  office  for  that  of  the  fenestra  rotunda,  and 
Savart  has  devised  a  little  apparatus  which 
very  prettily  illustrates  the  manner  in  which 
this  may  take  place.  In  a  disc  of  wood 
(«  b,  fig.  265) 

of   a  sufficient  Fig.  265. 

thickness,  he  hoi-  ^  

lows  out  two  ca- 

vities,  o  and  r,  f  r  \ 

which  commu-  f  (  o  \r."=_n— J  J 
nicate  at  their  i  J 
bottoms      with  & 

each  other  by  a  ^  

narrow  canal  (c)   ■  

hollowed  in  the  wood,  but  not  open  on  its  sur- 
face ;  a  thin  membrane  is  extended  over  each 
of  the  cavities.  Thus,  the  air  contained  in 
these  cavities  may  pass  easily  from  one  to  the 
other,  and  may  always  maintain  the  same 
degree  of  elastic  tension  in  both.  If,  then, 
a  vibrating  glass  be  brought  .near  the  mem- 
brane r  covered  with  a  layer  of  sand,  it  will 
be  found  to  enter  freely  into  vibration,  as 
evinced  by  the  active  movements  of  the  grains 
of  sand.  If  now  pressure  be  made  with  the 
finger  on  o,  r  will  become  convex  in  propor- 
tion as  o  is  rendered  concave  by  the  pressure, 
and  when  in  this  state,  the  movements  of  the 
sand  will  be  much  less  considerable  than  be- 
fore, presenting  an  effect  precisely  similar  to 
that  produced  on  the  tympanic  membrane  by 
an  increase  of  tension.  Thus,  the  extent  of 
the  excursions  of  the  vibrations  of  the  mem- 
brane r  is  limited  by  the  pressure  exerted  upon 
o,  and  as  the  membranes  of  the  two  fenestras 
are  related  to  each  other  in  an  analogous  man- 
ner, we  may  argue  that  pressure  upon  the  larger 
one,  that  of  the  fenestra  ovalis,  will  occasion 
tension  of  the  smaller,  that  of  the  fenestra 
rotunda,  thereby  limiting  the  extent  of  the 
excursions  of  its  vibrations. 

Moreover  it  appears,  upon  reference  to  the 
anatomy  of  these  parts,  (see  fig.252,  p.  550,)  that 
the  only  muscles  which  have  been  satisfactorily 
demonstrated  are  tensors  of  the  tympanum ;  and 
that  at  whatever  extremity  of  the  chain  of  ossicles 
muscular  effort  be  first  exerted,  a  correspond- 
ing effect  will  be  produced  at  the  other  ;  that 
when  the  stapedius  muscle  acts,  the  malleus  is 
thrown  into  a  position  favourable  to  the  tension 
of  the  membrana  tympani,  and,  on  the  other 
hand,  the  contraction  of  the  internus  mallei 
depresses  the  stapes,  and  consequently  in- 
creases the  tension  of  the  membranes  of  the  two 
fenestra.   The  cessation  of  muscular  action 


restores  all  three  membranes  to  their  original 
laxity,  nor  does  it  appear  that  they  admit  of 
any  further  degree  of  relaxation  through  the 
influence  of  any  vital  process.  The  incus 
forms  a  bond  of  connexion  between  the  two 
other  bones,  and  its  motions  depend  entirely 
upon  theirs  in  consequence  of  its  articulation 
with  both,  while  from  the  fixedness  of  its  con- 
nexion with  the  mastoid  cells,  as  well  as  its 
intermediate  position,  and  its  not  having  any 
muscles  inserted  into  it,  it  is  obvious  that  its 
motions  must  be  much  more  limited  than  those 
of  the  other  bones.  Its  use  seems  to  be  to 
complete  the  chain  in  such  a  way,  that  by 
reason  of  its  double  articulation  with  the  mal- 
leus on  the  one  hand  and  the  stapes  on  the 
other,  the  tension  of  the  tympanic  membranes 
may  be  regulated  without  any  sudden  or  vio- 
lent motion,  which  could  scarcely  be  avoided 
were  the  conductor  between  the  membranes  of 
the  tympanum  and  fenestra  ovalis  one  piece  of 
bone. 

But  whence  the  necessity  of  at  all  adding 
to  the  ear  this  complex  apparatus  of  tympanum 
and  tympanic  membrane,  and  why  might  not 
the  sonorous  impressions  have  been  made  di- 
rectly upon  the  membranes  which  close  the 
openings  to  the  labyrinth  ?  Upon  this  point 
Savart  has  offered  a  conjecture  which  seems  to 
afford  the  most  probable  explanation  as  to  the 
true  object  of  these  parts.  If  the  membranes 
of  the  fenestra,  he  says,  had  been  in  imme- 
diate contact  with  the  atmosphere,  their  elastic 
state  would  have  been  constantly  undergoing 
changes,  under  the  influence  of  the  vicissitudes 
of  temperature  of  the  air,  a  circumstance  which 
would,  in  all  probability,  impair  the  power  of 
the  organ  in  detecting  differences  of  sounds. 
He  presumes  therefore  that  the  membrana  tym- 
pani prevents  this  contact  of  the  atmosphere 
with  the  membranes  of  the  labyrinth,  and  that 
the  cavity  of  the  tympanum  and  the  mastoid 
cells  form  a  kind  of  receptacle  in  which  the 
air,  which  finds  its  way  into  the  tympanum 
through  the  Eustachian  tube,  acquires  the  con- 
stant temperature  of  the  body,  and  establishes 
in  front  of  the  openings  of  the  labyrinth  a  sort 
of  atmosphere  proper  to  themselves,  the  tem- 
perature of  which  does  not  vary. 

This  same  acute  observer  remarks  that  the 
size  of  the  membrana  tympani  in  all  proba- 
bility, in  the  different  species  of  animals, 
exerts  much  influence  upon  the  number  of 
sounds  which  they  can  perceive,  and  at  the 
same  time  upon  the  limits  at  which  those 
sounds  begin  or  cease  to  be  audible.  Were 
the  tympanic  membrane  in  man  of  greater  size 
than  it  is,  there  is  no  doubt  that  instead  of 
beginning  to  hear  sounds  which  result  from 
about  thirty  vibrations  in  a  second,  we  should 
be  able  to  hear  only  sounds  of  a  higher  pitch. 
Moreover  it  may  be  reasonably  presumed  that 
animals  who  have  the  membrana  tympani 
much  larger  than  that  of  man,  hear  much 
graver  sounds  than  those  which  result  from 
thirty  vibrations  in  a  second  ;  and,  on  the  other 
hand,  there  must  be  other  animals  who  hear 
very  acute  sourds  only. 

Even  in  the  human  species,  we  observe  in 


HEARING. 


575 


different  individuals  a  similar  variation  in  the 
limits  of  sensibility  to  sounds,  that  is,  we  find, 
in  the  words  of  Dr.  Wollaston,  that  "  an  ear 
which  would  be  considered  as  perfect  with 
regard  to  the  generality  of  sounds,  may  at  the 
same  time  be  completely  insensible  to  such  as 
are  at  one  or  the  other  extremity  of  the  scale 
of  musical  notes,  the  hearing  or  not  hearing 
of  which  seems  to  depend  wholly  on  the  pitch 
or  frequency  of  vibration  constituting  the  note, 
and  not  upon  the  intensity  or  loudness  of  the 
noise."*  And  we  owe  to  this  distinguished 
man  the  knowledge  of  the  interesting  fact, 
that  an  insensibility  of  the  ear  to  low  sounds 
may  be  artificially  induced,  by  exhausting  the 
cavity  of  the  tympanum  to  a  great  degree. 
This  may  be  effected  by  forcibly  attempting  to 
take  breath  by  expansion  of  the  chest,  the 
mouth  and  nose  being  kept  shut ;  after  one 
or  two  attempts,  the  pressure  of  the  external 
air  is  strongly  felt  upon  the  membrana  tympani, 
which  is  thus  from  the  external  pressure  thrown 
into  a  state  of  considerable  tension.  An  ear 
in  this  state  becomes  insensible  to  grave  tones, 
without  losing  in  any  degree  the  perception  of 
more  acute  ones.  This  induced  defective  state 
of  the  ear,  from  exhaustion  of  the  tympanum, 
may  even  be  preserved  for  some  time  without 
the  continued  effort  of  inspiration  and  without 
even  stopping  the  breath,  and  may  in  an  in- 
stant be  removed  by  the  act  of  swallowing. 
In  repeating  this  experiment  as  I  sit  writing  at 
my  desk,  I  perceive  that  a  great  degree  of 
stillness  ensues  immediately  the  sensation  of 
pressure  upon  the  tympanic  membrane  is  felt, 
owing  no  doubt  to  the  low  rumbling  noise  of 
the  waggons  and  carriages  in  the  street  being 
imperfectly  audible.  A  similar  observation 
was  made  by  Dr.  Wollaston :  "  If  I  strike  the 
table  before  me  with  the  end  of  my  linger," 
he  says,  "  the  whole  board  sounds  with  a  deep 
dull  note.  If  I  strike  it  with  my  nail,  there 
is  also  at  the  same  time  a  sharp  sound  pro- 
duced by  quicker  vibrations  of  parts  around 
the  point  of  contact.  When  the  ear  is  ex- 
hausted, it  hears  only  the  latter  sound,  without 
perceiving  in  any  degree  the  deeper  note  of  the 
whole  table.  In  the  same  manner,  in  listening 
to  the  sound  of  a  carriage  the  deeper  rumbling 
noise  of  the  body  is  no  longer  heard  by  an 
exhausted  ear;  but  the  rattle  of  a  chain  or 
screw  remains  at  least  as  audible  as  before 
exhaustion."  Dr.  Wollaston  refers  to  the  cu- 
rious effect  produced  by  trying  this  experiment 
at  a  concert :  "  none  of  the  sharper  sounds  are 
lost,  but  by  the  suppression  of  a  great  mass  of 
louder  sounds  the  shriller  ones  are  so  much 
the  more  distinctly  perceived,  even  to  the  rat- 
tling of  the  keys  of  a  bad  instrument,  or 
scraping  of  catgut  unskilfully  touched."  Ano- 
ther very  interesting  circumstance  connected 
with  this  subject  is  the  production  of  the  same 
condition  of  the  tympanum  by  the  sudden  in- 
crease of  external  pressure  as  well  as  by  the 
decrease  of  that  within,  as  occurs  in  the  diving- 
bell  as  soon  as  it  touches  the  water,  the  pres- 

*  Wollaston  on  Sounds  inaudible  by  certain 
Ears.    Phil.  Trans.  1820. 


sure  of  which,  according  to  Wollaston,  upon 
the  included  air  closes  the  Eustachian  tube,  and 
in  proportion  to  the  descent  occasions  a  degree 
of  tension  on  the  tympanum,  that  becomes 
distressing  to  persons  who  have  not  learned  to 
obviate  this  inconvenience." 

From  one  opportunity  which  I  had  of  de- 
scending in  the  diving-bell  now  exhibiting  at  the 
Polytechnic  Institution  in  Regent-street,  I  ex- 
perienced this  sensation  very  strongly,  and 
exactly  as  Dr.  Wollaston  describes  it.  The 
first  effect  of  the  pressure  on  the  tympanic 
membrane  was  the  production  of  a  crackling 
noise,  which  was  immediately  succeeded  by  a 
painful  sense  of  pressure  in  both  ears ;  but  this 
is  immediately  relieved  by  the  act  of  swallow- 
ing ;  it  soon  however  recurs,  and  may  be  in  a 
like  manner  again  relieved.  I  had  no  means 
of  judging  exactly  as  to  the  limits  of  audition  ; 
but  I  distinctly  observed  in  conversation  with 
those  who  descended  with  me,  that  grave  tones 
were  those  least  distinctly  heard ;  the  grave 
tones  of  my  own  voice  also  were  less  distinct  as 
well  as  the  low  notes  in  whistling. 

In  such  cases  then  it  would  appear  that  from 
the  strong  compression  exerted  on  the  mem- 
brana tympani,  that  membrane  cannot  vibrate 
in  unison  with  tones  which  result  from  a  small 
number  of  vibrations.  On  the  other  hand  we 
may  infer,  from  Dr.  Wollaston's  observations, 
that  "  human  hearing,  in  general,  is  more  con- 
fined than  is  generally  supposed  with  regard 
to  its  perception  of  very  acute  sounds,  and  has 
probably  in  every  instance  some  definite  limit 
at  no  great  distance  beyond  the  sounds  ordi- 
narily heard."  The  ordinary  range  of  human 
hearing  comprised  between  the  lowest  notes  of 
the  organ  and  the  highest  known  cry  of  insects, 
includes,  according  to  Wollaston,  more  than 
nine  octaves,  the  whole  of  which  are  distinctly 
perceptible  by  most  ears.  Dr.  Wollaston  has, 
however,  related  some  cases  in  which  the  range 
was  much  less,  and  limited  as  regards  the  per- 
ception of  high  notes ;  in  one  case,  the  sense 
of  hearing  terminated  at  a  note  four  octaves 
above  the  middle  E  of  the  piano-forte;  this 
note  he  appeared  to  hear  rather  imperfectly,  but 
the  F  above  it  was  inaudible,  although  his 
hearing  in  other  respects  was  as  perfect  as  that 
of  ordinary  ears ;  another  case  was  that  of  a 
lady  who  could  never  hear  the  chirping  of  the 
gryllus  campestris;  and  in  a  third  case  the 
limit  was  so  low  that  the  chirping  of  the  com- 
mon house-sparrow  could  not  be  heard.  Dr. 
Wollaston  supposes  that  inability  to  hear  the 
piercing  squeak  of  a  bat  is  not  very  rare,  as  he 
met  with  several  instances  of  persons  not  aware 
of  such  a  sound. 

The  opinion  prevailed  for  a  long  time  that 
rupture  or  destruction  of  the  membrana  tym- 
pani is  necessarily  followed  by  the  loss  of  the 
sense.  But  Sir  A.  Cooper  proved  distinctly 
that  not  only  was  hearing  not  destroyed,  but 
that  in  some  cases  of  deafness  it  might  be 
punctured  with  considerable  benefit  to  the 
patient.*  The  most  frequent  cause  of  destruc- 
tion of  the  tympanum  is  otitis,  and  provided 

*  Phil.  Trans,  for  1800  and  1801. 


576 


HEARING. 


the  suppurative  process  does  not  extend  so  far 
as  to  destroy  the  stapes,  the  hearing  is  only 
impaired;  but  should  that  bone  and  its  attached 
membrane  suffer,  then  a  total  deafness  is  the 
consequence.  In  one  case,  related  by  Sir  A. 
Cooper,  the  membrana  tympani  was  entirely 
destroyed  on  the  left  side,  and  partially  so  on 
the  right,  yet  this  gentleman,  if  his  attention 
were  excited,  was  capable,  when  in  company, 
of  hearing  whatever  was  said  in  the  usual  tone 
of  conversation,  but  it  was  remarkable  that  he 
heard  better  with  the  left  ear  than  with  the 
right,  although  in  the  former  there  were  no 
traces  of  a  membrana  tympani.  He  could  not 
hear  from  as  great  a  distance  as  others,  and  he 
stated  that,  in  a  voyage  he  had  made  to  the 
East  Indies,  while  others,  when  ships  were 
hailed  at  sea,  could  catch  words  with  accuracy, 
his  organ  of  hearing  received  only  an  indistinct 
impression.  His  musical  ear  was  not  impaired, 
"  for  he  played  well  on  the  flute  and  had  fre- 
quently boine  a  part  in  a  concert.''  The  ex- 
ternal ear  too  had  acquired  a  considerable 
degree  of  mobility  under  the  direction  of  the 
will,  so  that  it  could  at  pleasure  be  raised  or 
drawn  backwards,  and  this  motion  was  ob- 
served to  take  place  whenever  the  attention 
was  directed  to  sounds  not  very  distinctly 
audible. 

The  Eustachian  tube  evidently  performs  a 
two-fold  office  : — it  is  the  passage  for  the  en- 
trance of  air  into  the  tympanic  cavity  from  the 
throat,  thus  affording  a  provision  for  keeping 
that  cavity  constantly  full  of  air  in  order  to 
allow  of  the  free  vibration  of  the  membranes  as 
well  as  of  the  chain  of  bones  ;  and  it  seems 
obvious  that  the  tube  communicates  with  the 
throat  in  order  that  the  air  introduced  through 
it  shall  have  acquired  the  temperature  of  the 
body.  It  likewise  affords  an  outlet  for  the  es- 
cape of  such  sonorous  undulations  as  do  not 
impinge  upon  the  labyrinthic  wall  of  the  tym- 
panum, which,  were  there  no  such  communica- 
tion with  the  external  air,  would  cause  an  echo, 
and  in  this  respect  it  performs  a  function  si- 
milar to  that  of  the  mastoid  cells.  The  neces- 
sity of  such  a  provision  as  is  afforded  by  the 
first  office  which  the  Eustachian  tube  performs, 
is  manifest  from  the  frequency  of  deafness  re- 
sulting from  a  stoppage  either  in  the  tube  or  at 
its  extremity.  Bressa  supposed  that  the  Eus- 
tachian lube  conducted  the  sonorous  impulses 
excited  by  one's  own  voice  from  the  cavity  of 
the  mouth  to  the  labyrinth  ;*  but  the  incor- 

*  Reil  and  Autenrieth,  Archiv.  fiir  die  Physiolo- 
gie,  B.  viii.  This  was  a  modification  of  an  opinion 
expressed  by  Boerhaave,  viz.,  that  those  sounds 
from  without  which  entered  the  mouth  were  conveyed 
to  the  labyrinth  through  the  Eustachian  tube.  An 
English  physiologist  advocates  the  opinion  that 
some  sounds  are  conveyed  through  the  Eustachian 
tube,  and  particularly  as  he  supposes  in  the  Cetacea, 
from  the  great  development  of  that  tube  in  these 
animals  compared  with  the  external  auditory  pas- 
sage, and  the  erroneous  notion  propagated  by  Home 
that  the  malleus  had  no  connexion  with  the  tym- 
panum, but  now  disproved  by  the  careful  exami- 
nation of  Professor  Owen.  See  Fletcher's  Phy- 
siology, and  Owen's  Edition  of  Hunter's  Animal 
Economy. 


rectness  of  this  notion  is  abundantly  proved  by 
the  fact  that  persons  who  labour  under  obstruc- 
tion of  this  tube  can  hear  their  own  voices 
plainly  enough,  while  they  are  deaf  to  those  of 
others.  Moreover,  if  we  introduce  into  the 
mouth  a  watch  or  a  vibrating  tuning  fork,  care 
being  taken  that  they  do  not  touch  any  of  the 
walls  of  the  mouth,  they  are  heard  gradually 
less  distinctly  as  they  are  approximated  to  the 
Eustachian  tube ;  indeed  when  held  far  back 
in  the  mouth  they  are  totally  inaudible.  In 
some  birds  the  air  of  the  tympanum  finds  its 
way  not  only  into  the  mastoid  cells,  but  also 
between  the  two  tables  of  the  skull,  as  in  the 
owl  and  in  singing  birds.  The  arrangement  of 
the  osseous  structure  corresponding  to  the 
diploe  is  exceedingly  beautiful  in  the  canary,  in 
which  I  have  examined  it.  The  two  tables 
seem  as  it  were  connected  by  very  fine  and  nu- 
merous bony  pillars,  the  extremities  of  which 
are  attached  to  each  table  ;  cells  freely  commu- 
nicating with  each  other  surround  these  pillars 
every  where,  and  the  air  from  the  tympanum 
thus  traverses  the  whole  of  this  cellular  struc- 
ture. The  superfluous  sonorous  undulations 
find  their  way  into  these  cells,  and  being  re- 
peatedly reflected  from  their  parietes  become 
greatly  weakened,  so  that  they  can  exert  no  fur- 
ther influence  upon  the  hearing. 

Functions  of  the  nerves. — The  nervous  ap- 
paratus connected  with  the  organ  of  hearing- 
consists  of  the  nerve  which  receives  the  sono- 
rous impressions,  and  of  other  nerves  which  are 
connected  with  the  mechanism  of  the  organ. 
That  the  portio  mollis  of  the  seventh  pair  an- 
swers to  the  former  office,  anatomy  alone  abund- 
antly proves.  With  respect  to  the  latter  nerves 
some  few  remarks  seem  necessary.  The  mus- 
cular apparatus  of  the  tympanic  ossicles  receives 
its  nerves  partly  from  the  facial  and  partly  from 
the  otic  ganglion,  thus  exhibiting  an  analogous 
arrangement  to  that  of  the  muscular  structure 
of  the  iris.  Such  an  analogy  renders  it  ex- 
tremely probable  that  the  actions  of  the  muscles 
of  the  ossicles  are  excited  in  a  similar  way  to 
that  in  which  the  iris  is  prompted  to  act.  The 
stimulus  of  sound  conveyed  to  that  portion  of 
the  nervous  centre  with  which  it  is  connected, 
excites  by  reflection  the  motor  power  of  the 
facial  nerve,  which,  through  its  connexion  di- 
rect or  indirect  with  the  muscles  of  the  ossicles, 
causes  them  to  act,  and  the  action  is  in  propor- 
tion to  the  intensity  of  the  sound,  inasmuch  as 
the  more  tense  the  membrane  of  the  tympanum, 
the  less  will  be  the  excursions  of  its  vibrations ; 
as  in  the  iris  the  more  intense  the  light,  the 
more  contracted  will  the  pupil  be.  It  is  im- 
possible in  the  present  state  of  our  knowledge 
to  say  what  is  the  office  of  the  chorda  tympani, 
or  whether  indeed  it  has  any  office  in  connexion 
with  hearing;  but  we  may  easily  conceive  that 
from  its  connexion  with  the  facial,  an  irritation 
of  it  may  excite  that  nerve.  Equally  ignorant 
are  we  of  the  function  of  the  tympanic  anas- 
tomosis. 

I  shall  conclude  with  the  following  brief 
summary  of  the  present  state  of  our  knowledge 
respecting  the  functions  of  the  several  portions 
of  the  organ  of  hearing. 


HEART. 


577 


1.  The  vestibule  is  the  essential  part  of  the 
organ.  It  detects  the  presence  and  intensity 
of  sound,  and  especially  of  those  sounds  con- 
veyed through  the  external  ear  and  tympanum. 

2.  The  cochlea,  lying  in  immediate  connec- 
tion with  the  bone,  receives  those  sounds  which 
are  propagated  through  the  bones  of  the  head. 
According  to  Kerner  it  is  the  medium  of  the 
perception  of  the  timbre  or  quality  of  sounds.* 

3.  Of  the  function  of  the  semicircular  canals 
we  know  nothing.  That  they  aid  in  forming  a 
judgment  of  the  direction  of  sounds  is  conjec- 
tured by  Autenrieth  and  Kerner,  and  more  re- 
cently by  Wheatstone. 

4.  The  tympanum  and  its  membrane  render 
the  internal  ear  independent  of  atmospheric 
vicissitudes,  and  the  former  affords  a  non-reci- 
procating cavity  for  the  free  vibration  of  the 
latter,  as  well  as  of  the  chain  of  ossicles. 

5.  The  chain  of  ossicles  acts  as  a  conductor 
of  vibrations  from  the  membrana  tympani  to 
the  fenestra  ovalis,  and  under  the  influence  of 
the  muscles  regulates  the  tension  of  the  mem- 
brana tympani,  as  well  a?  the  membrane  of  the 
fenestra  rotunda,  so  as  to  protect  the  ear  against 
the  effects  of  sounds  of  great  intensity. 

6.  The  external  ear  and  meatus  are  con- 
ductors of  vibrations  ;  the  former  in  some  de- 
gree collects  them  as  a  hearing-trumpet  would 
do,  and  probably  assists  in  enabling  us  to  judge 
of  the  direction  of  sounds. f 

(R.  B.  Todd.) 

HEART  (in  anatomy).  G 
Lat.  cor;  Fr.  caur ;  Germ.  Herz  ;  Ital.  cuore. 
The  movement  of  nutritious  juices  through  the 
texture  or  textures  of  which  an  organized  body 
is  composed,  is  a  fundamental  law  in  Physio- 
logy. In  proportion  as  the  vital  actions  become 
more  complex  and  energetic,  the  more  a  rapid 
and  certain  circulation  of  these  fluids,  which 
is  intimately  connected  with  this  condition, 
becomes  indispensable,  and  for  this  purpose 
we  have  a  pulsatory  sac  or  sacs,  called  hearts, 
superadded  to  the  circulatory  apparatus.  Ano- 
ther invariable  concomitant  of  this  energetic 
manifestation  of  the  vital  phenomena  is  the 
more  perfect  exposure  of  the  nutritious  fluids 
to  the  atmospheric  air,  and  this,  combined  with 

*  Muller,  who  seems  to  regard  the  cochlea  as  an 
apparatus  for  distinguishing  the  pitch  of  notes, 
accounts  for  its  peculiar  form  thus:  — He  supposes 
it  an  organ  in  which  the  separate  parts  of  the  nerve 
may  he  exposed  to  excitation;  for  this  purpose  all 
the  finest  fibres  of  the  nerve  lie  exposed  to  the  in- 
fluence of  the  sound-conducting  medium,  and  that 
it  has  assumed  the  spiral  form  in  order  that  the 
nerves  may  be  arranged  in  the  most  convenient 
manner  and  within  the  smallest  space.  SeehisFrag- 
ment  on  the  sense  of  hearing  appended  to  his  work, 
Zur  vergleichenden  Physiologie  des  Gesichtssinnes. 

t  Much  remains  to  be  done  to  determine  the  true 
means  by  which  we  judge  of  the  direction  of  sound. 
The  reader  who  may  be  interested  on  the  subject 
will  find  some  valuable  observations  and  experi- 
ments in  Autenrieth  and  Kerner's  paper  already 
quoted,  Mr.  Gough's  paper  in  the  Manchester 
Memoirs,  vol.  v.,  new  series,  and  one  by  Venturi 
in  Voigt's  Magazin  f.  d.  Neueste  aus  der  Physik. 
Mr.  Wheatstone's  views  are  very  briefly  stated  in 
Dr.  Elliotson's  Physiology. 

vol.  ir. 


the  dissimilar  media  in  which  different  animals 
live  and  move,  necessitates  very  important 
modifications  in  the  number,  position,  and 
structure  of  these  pulsatory  sacs.  These  hearts 
were  until  lately  supposed  to  be  exclusively 
confined  to  the  sanguiferous  vessels,  but  Muller 
and  Panizza  have  discovered  distinct  pulsating 
sacs  placed  upon  the  lymphatic  vessels  in 
several  of  the  reptile  tribe,  and  these  may  be 
considered  lymphatic  hearts. 

In  the  lowest  organized  plants,  as  the  Fungi, 
Alga;,  &c.  and  in  the  lower  classes  of  animals, 
as  the  Polypi,  Actiniae,  and  a  great  part  of  the 
intestinal  worms,  the  nutritious  fluids  are  trans- 
mitted through  their  substance  without  any 
distinct  canals  or  tubes  ;  while  in  the  higher 
classes  of  plants,  and  in  the  Medusa,  &c. 
among  animals,  vessels  are  present,  but  these 
are  unprovided  with  any  pulsatory  cavities.  In 
the  articulated  animals  generally,  the  vessels 
are  still  without  any  pulsatory  cavities ;  but  to 
make  up  for  the  deficiency,  the  dorsal  vessel 
itself  has  a  distinct  movement  of  contraction 
and  relaxation.  Various  pulsatory  dilatations 
are  placed  upon  the  vascular  system  of  the 
common  worm  ( Lumbricus  terrestris )  ;  one  or 
two  upon  the  vascular  system  of  the  Holo- 
thuria  ;  and  one  in  the  Talpa  cristata,  where 
the  dorsal  vessel  is  reflected  upon  itself  at  the 
posterior  extremity  of  the  body  to  become  con- 
tinuous with  an  analogous  ventral  vessel ;  all 
of  which  may  be  considered  as  rudimentary 
hearts. 

As  we  rise  in  the  scale  of  animals,  we  find 
that  the  heart  consists  of  two  distinct  portions — 
of  a  stronger  and  more  muscular  cavity  called 
a  ventricle,  and  of  a  weaker  and  less  muscular 
cavity  called  an  auricle.  The  latter  not  only 
serves  as  a  kind  of  reservoir  to  the  former,  but 
also,  by  the  contraction  of  its  muscular  fibres, 
drives  the  blood  into  it.  This  heart  is  placed 
within  a  sac  or  pericardium,  and  possesses 
valves  to  prevent  the  regurgitation  of  the  blood 
from  the  ventricle  into  the  auricle,  and  from 
the  aorta  back  again  into  the  ventricle.  This 
may  be  considered  as  a  perfect  single  heart. 
This  single  heart  in  some  of  the  Mollusca  and 
in  Fishes  which  have  a  double  circulation, 
propels  the  blood  not  only  through  the  lungs, 
but  also  through  the  body.  In  the  Batrachian 
Reptiles,  as  in  the  Frog,  though  the  circulation 
is  single,  the  heart  becomes  more  complicated  ; 
for  instead  of  a  single  auricle  we  have  two,  one 
of  which  receives  the  blood  returning  from  the 
respiratory  apparatus,  the  other  receives  the 
venous  blood  of  the  body.  The  pulmonic  and 
systemic  circulations  are  here  separated  as  far 
as  the  auricles  are  concerned ;  but  a  single 
ventricle  in  which  the  venous  and  arterialized 
blood  are  intermixed,  still  continues  to  propel 
the  sanguineous  current  both  through  the  lungs 
and  through  the  body.  In  the  Ophidia  or  ser- 
pent tribe  the  heart  possesses  the  same  number 
of  cavities  as  in  the  Batrachian  Reptiles  ;  but 
we  have  a  still  nearer  approach  to  the  double 
circulation  in  the  presence  of  a  rudimentary 
septum  ventriculorum.  In  some  of  the  Sauria, 
as  the  Crocodile,  the  ventricle  is  divided  by 
partitions  into  distinct  chambers,  which  never- 

2  Q 


578 


HEART. 


theloss  communicate  freely  with  each  other.  It 
would  appear,  however,  from  Meckel's  descrip- 
tion, that  the  ventricle  is  divided  by  a  complete 
septum  into  two  separate  and  distinct  chambers 
in  the  Crocodilus  Lucius.  In  the  Mammalia 
and  Birds,  where  no  intermixture  of  the  venous 
and  arterialized  blood  takes  place,  but  where 
all  the  blood  sent  along  the  aorta  has  been  pre- 
viously subjected  freely  to  the  influence  of  the 
atmospheric  air,  we  find  two  distinct  hearts, 
which  in  the  adult  have  no  communication 
with  each  other;  one  the  respiratory  heart  for 
the  transmission  of  the  blood  through  the  lungs, 
the  other  the  systemic  heart  for  the  transmission 
of  the  arterialized  blood  through  all  the  textures 
of  the  body.  These  are  not  placed  separate 
from  each  other,  as  in  some  of  the  Mollusca, 
which  with  a  double  circulation  have  an  aquatic 
respiration,  but  are  in  juxta-position,  and  in 
fact  many  of  the  muscular  fibres  are  common 
to  both. 

Human  Heart  ( normal  anatomy ). 
Position. — The  heart  in  the  human  species 
is  lodged  within  the  cavity  of  the  thorax,  occu- 
pies the  middle  mediastinum,  and  is  enclosed 
in  a  fibro-serous  capsule  called  pericardium. 
It  is  placed  obliquely  from  above  downwards 
and  from  behind  forwards,  in  front  of  the  spine 
and  behind  the  sternum.  The  apex  is  directed 
downwards,  forwards,  and  to  the  left  side,  pro- 
jects into  the  notch  on  the  anterior  margin  of 
the  left  lung,  and  in  the  quiescent  state  of  the 
organ  corresponds  to  the  posterior  surface  of 
the  cartilage  of  the  sixth  rib.  The  base  looks 
upwards,  backwards,  and  to  the  right  side ;  is 
separated  from  the  anterior  part  of  the  spine  by 
the  pericardium,  oesophagus,  aorta,  and  other 
parts  which  lie  in  the  posterior  mediastinum ; 
and  extends  from  about  the  fourth  to  the  eighth 
dorsal  vertebra.  Its  right  margin  rests  upon 
the  upper  surface  of  the  cordiform  tendon  of 
the  diaphragm,  by  which  it  is  separated  from 
the  stomach  and  liver;  its  left  margin,  which 
is  more  vertical,  looks  upwards  and  to  the  left 
side,  and  occupies  an  excavation  on  the  inner 
surface  of  the  left  lung.  Its  posterior  or  flat 
surface  rests  partly  upon  the  cordiform  tendon 
of  the  diaphragm,  having  the  pericardium  inter- 
posed between  them,  and  partly  upon  the  inner 
concave  surface  of  the  left  lung.*  Its  position 
corresponds  to  the  union  of  the  superior  third  of 
the  body  with  the  two  inferior  thirds.  The  lungs 
overlap  the  lateral,  and  part  (rarely  the  whole) 
of  the  anterior  portion  of  the  heart,  leaving 
only  in  general  about  an  inch  and  a  half  or 
two  square  inches  of  the  anterior  surface  of  the 
right  ventricle  uncovered  by  the  lung.  It  is  of 
importance  to  remember  this  fact  in  percussing 
this  region.  The  two  sacs  of  the  pleura,  as 
they  pass  between  the  spine  and  sternum  to 
form  the  mediastina,  are  interposed  between 
the  lungs  and  the  heart.  The  heart  is  subject 
to  slight  change  of  position  from  the  influence 
of  the  contiguous  organs.  It  is  carried  a  little 
downwards  during  violent  contraction  of  the 

*  In  the  lower  animals  its  position  is  vertical, 
occupying  the  mesial  line  of  the  body. 


diaphragm,  and  is  pressed  upwards  when  the 
abdominal  viscera  are  strongly  compressed  by 
the  powerful  contraction  of  the  abdominal 
muscles.  During  expiration  it  has  been  seen 
to  recede  deeper  into  the  thorax,  and  during 
inspiration  again  to  come  forward.  When  the 
body  is  bent  to  the  right  side,  the  apex  recedes 
from  the  inner  side  of  the  left  wall  of  the 
thorax  ;  when  bent  to  the  left  side,  it  is  still 
more  closely  approximated  to  it. 

Form  and  external  surface. — Its  form  is  that 
of  a  flattened  cone,  and  it  is  neither  symme- 
trical as  regards  the  mesial  line  of  the  body, 
nor  (as  we  shall  afterwards  find)  is  the  organ 
itself  symmetrical.  It  presents  an  anterior  and 
a  posterior  surface;  a  right  inferior  or  acute 
margin ;  a  left  superior  or  obtuse  margin  ;  a 
base,  and  an  apex.  Its  anterior  surface,  which 
is  also  turned  towards  the  left  side,  is  convex 
and  considerably  longer  than  the  posterior  and 
right,  which  is  flattened.  On  the  anterior  sur- 
face of  the  heart  we  find  a  distinct  groove, 
running  nearly  in  the  axis  of  the. organ,  passing 
from  above  downwards  and  from  right  to  left, 
and  containing  the  left  coronary  artery.  A 
larger  portion  of  the  heart  appears  to  lie  to  the 
right  than  to  the  left  of  this  groove.  There  is 
a  similar  groove  on  the  posterior  surface,  which 
is  nearly  vertical,  shorter  than  the  anterior,  and 
contains  a  branch  of  the  right  coronary  artery. 
These  two  grooves  are  connected  with  each 
other  at  or  near  the  apex  generally  by  a  small 
notch,  which  is  sometimes  of  sufficient  depth 
to  give  the  heart  a  bifid  appearance.*  These 
grooves  mark  the  division  of  the  heart  into 
right  and  left  sides.  These  terms  are,  how- 
ever, more  applicable  when  describing  the 
organ  in  the  lower  animals ;  for  in  the  human 
species  the  right  side  is  also  anterior  and  infe- 
rior, and  the  left  side  posterior  and  superior. 
Near  the  base  of  the  heart  and  at  the  com- 
mencement of  the  longitudinal  grooves,  we  find 
a  circular  groove  deeper  anteriorly  than  poste- 
riorly, which  contains  in  its  posterior  part  the 
coronary  vein  and  branches  of  the  coronary 
arteries.  This  circular  groove  points  out  the 
division  between  the  auricular  and  ventricular 
portions  of  the  heart.  Two  large  arteries  are 
placed  in  front  of  the  anterior  part  of  this 
groove,  the  one  posterior  to  the  other.  That 
nearest  to  the  groove  is  the  aorta,  which  springs 
from  the  base  of  the  left  ventricle ;  the  one 
placed  anterior  is  the  pulmonary  artery,  which 
arises  from  the  upper  part  of  the  right  ventricle, 
and  at  its  origin  covers,  along  with  that  part  of 
the  ventricle  to  which  it  is  attached,  the  com- 
mencement of  the  aorta.  The  ventricles  form 
the  principal  part  of  the  heart,  and  occupy  the 
middle  and  apex,  while  the  auricles  are  placed 
at  the  base.  The  base  of  the  ventricles  is  con- 
nected to  the  base  of  the  auricles.  Two  large 
veins,  the  superior  and  inferior  vense  cavae, 

*  This  notch  in  the  human  heart  looks  like  the 
rudiments  of  the  fissure  which  in  the  Dugong  and 
Rytina  separates  the  two  ventricles  from  each  other 
nearly  up  to  the  base.  This  bifid  form  of  the  heart, 
which  is  merely  a  temporary  condition  in  the  hu- 
man species,  is  permanent  in  the  Dugong  and  Ry- 
tina.   See  Jig.  264,  vol.  i.  p.  576. 


HEART. 


579 


enter  the  right,  and  the  four  pulmonary  veins 
pass  into  the  left  auricle.  The  apex  of  the 
heart  is  in  general  formed  by  the  left  ventricle 
alone.  The  base  of  the  ventricles  is  cut  ob- 
liquely from  before  backwards  and  from  above 
downwards,  and  this  explains  how  the  anterior 
surface  of  the  ventricles  should  be  longer  than 
the  posterior.  I  have  found  the  difference  of 
length  between  the  two  surfaces  in  a  consi- 
derable number  of  uninjected  hearts  to  vary 
from  half  an  inch,  or  rather  less,  to  an  inch. 
There  is  little  difference  between  the  length  of 
the  two  ventricles  in  the  uninjected  heart.  In 
the  injected  heart  the  anterior  wall  not  only 
becomes  elongated  but  much  more  convex, 
while  the  posterior  wall  is  simply  elongated, 
so  that  the  diffeience  in  length  between  the 
anterior  and  posterior  surfaces  becomes  in- 
creased. This  change  is  more  marked  in  the 
right  ventricle  than  in  the  left.  Cruveilhier 
slates  that  he  found  the  anterior  surface  of  the 
left  ventricle  to  exceed  the  posterior  by  nine  or 
ten  lines,  and  the  anterior  surface  of  the  right 
to  exceed  the  posterior  by  fifteen  lines.  These 
measurements  have  evidently  been  taken  from 
injected  hearts.  On  the  surface  of  the  heart, 
but  more  particularly  upon  the  anterior  surface 
of  the  right  ventricle,  a  white  spot,  varying  in 
size,  is  frequently  observed.  According  to 
Baillie  it  is  placed  on  the  free  or  inner  surface 
of  the  external  serous  membrane.*  These  spots 
are  so  common  an  appearance  that  it  is  some- 
what difficult  to  believe  that  they  are  morbid. 
It  is,  however,  very  probable  that  they  are  the 
result  of  some  inflammatory  action. 

■Except  in  very  emaciated  subjects  there  is  a 
greater  or  less  quantity  of  fat  occupying  the 
auricular  and  ventricular  grooves.  This  fat  is 
generally  in  greater  abundance  in  old  subjects 
than  in  young,  in  accordance  with  the  general 
law,  that  the  adipose  tissue  in  young  persons 
is  principally  collected  on  the  surface,  and  in 
old  persons  around  the  internal  organs.  When 
in  greater  quantity,  it  is  deposited  along  the 
ramifications  of  the  coronary  vessels,  and  may, 
in  cases  of  great  obesity,  almost  completely 
envelope  the  surface  of  the  heart.  It  is  gene- 
rally placed  in  greater  quantities  on  the  right 
side  than  on  the  left. 

The  human  heart  may  be  considered  as  con- 
sisting of  two  distinct  hearts  separated  from 
each  other  by  a  fleshy  septum,  and  which  in 
the  adult  have  in  general  no  communication. 
The  position  of  the  fleshy  septum  separating 
the  ventricles  is  marked  by  the  ventricular 
grooves.  Each  heart  consists  of  an  auricle  and 
ventricle  which  communicate  by  a  large  orifice. 
The  right  heart  is  occasionally  termed  the  pul- 
monic heart,  from  its  circulating  the  blood 
through  the  lungs ;  and  as  it  circulates  the 
dark  blood  it  was  termed  the  Caur  a  sang  noir 
by  Bichat.  The  left  is  occasionally  called  sys- 
temic  heart,  as  it  circulates  the  blood  through 

*  In  three  hearts  in  which  I  carefully  examined 
these  white  patches,  I  could  distinctly  trace  the 
serous  membrane  over  them.  See  the  observations 
of  M.  Bizot  (Memoires  de  la  Societe  Medicale 
d'Observation  de  Paris,  torn.  i.  p.  347,  1836,)  on 
these  spots. 


the  body  generally,  and  is  the  caur  d  saiig  rouge 
of  Bichat.  The  auricles,  from  their  immediate 
connexion  with  the  large  veins  of  the  heart, 
sometimes  receive  the  name  of  venous  portion 
of  the  heart  ( pars  cordis  venosa) ;  and  in  the 
same  manner  the  term  arterial  portion  of  the 
heart  ( purs  cordis  arteriosa )  has  been  applied 
to  the  ventricles  from  dieir  connexion  with  the 
large  arteries.  In  describing  the  different  ca- 
vities of  the  heart  we  shall  take  them  in  the 
order  in  which  the  blood  passes  through  them. 

Right  auricle  ( auricula  dextra  vel  inferior, 
atrium  venarum  cavarum ).  External  surface. 
— To  see  the  external  form  of  the  auricles  pro- 
perly it  is  necessary  that  they  be  first  filled 
with  injection.  The  right  auricle  is  of  an  irre- 
gular figure,  having  some  resemblance  to  a 
cube,  and  occupies  the  anterior,  right,  and  in- 
ferior part  of  the  base  of  the  heart.  It  receives 
all  the  systemic  venous  blood  of  the  body. 
Its  inferior  portion  rests  upon  the  diaphragm. 
Its  largest  diameter  runs  in  a  direction  from 
behind  forward,  and  from  right  to  left.  It  is 
broadest  posteriorly,  becoming  narrow  and  pro- 
longed anteriorly,  where  it  terminates  in  a 
small  and  free  appendix,  which,  from  its  re- 
semblance to  the  external  ear  of  the  dog,  has 
been  termed  auricle.  This  appendix  is  gene- 
rally serrated  on  the  edges,  more  particularly 
on  the  external,  and  projects  between  the  aorta 
and  the  upper  and  anterior  margin  of  the  right 
ventricle.  To  this  smaller  portion  the  term 
proper  auricle  has  been  given,  while  the  larger 
portion  has  been  called  sinus  vcnosus.  This 
division  of  the  auricle  into  proper  auricle  and 
sinus  venosus  is  more  distinct  in  the  left  than 
in  the  right  auricle.  The  posterior  surface  of 
the  right  auricle  is  connected  with  the  entrance 
of  the  two  cava? ;  its  inferior  with  the  base  of 
the  right  ventricle ;  its  internal  with  the  left 
auricle;  its  outer  surface  is  free;  and  anteriorly 
it  is  prolonged  into  the  proper  auricle.  The 
junction  of  its  internal  surface  with  the  cor- 
responding surface  of  the  opposite  auricle  is 
marked  by  an  indistinct  groove,  which  cor- 
responds to  the  attachment  of  the  septum  sepa- 
rating the  two  auricles.  Its  external  surface  is 
placed  on  a  plane  internal  to  the  outer  edge  of 
the  ri;j;ht  ventricle. 

Internal  surface. — The  innpr  surface  of  the 
right  auricle  can  be  satisfactoiily  examined  only 
when  it  is  opened  in  situ.  Its  interior  can  be 
best  exposed  by  making  a  longitudinal  incision 
from  the  appendix  to  the  orifice  of  the  inferior 
cava,  then  opening  the  superior  cava  along  its 
anterior  surface  and  connecting  the  two  inci- 
sions. The  inner  aspect  of  the  right  auricle 
presents  four  surfaces: — 1.  a  posterior,  where 
the  two  venje  cavee  enter ;  2.  an  outer,  upon 
which  numerous  muscular  bands  are  seen 
standing  in  relief;  3.  an  internal,  which  is 
nearly  smooth,  forms  the  septum  between  the 
two  auricles,  and  presents  an  oval  depression, 
about  the  size  of  the  point  of  the  finger,  called 
the  fossa  ovalis  ;  4.  an  anterior,  formed  by  the 
appendix,  and  which  also  presents  numerous 
muscular  bundles.  The  superior  or  descend- 
ing vena  cava  enters  at  the  upper  and  posterior 
angle,  the  inferior  or  ascending  cava  at  the 

2  Q  2 


530 


HEART. 


posterior  and  inferior.  The  entrance  of  the 
superior  cava  looks  downwards  and  forwards 
in  the  direction  of  the  body  of  the  auricle;  the 
entrance  of  the  cava  inferior  is  directed  up- 
wards, backwards,  and  inwards.  These  two 
orifices  are  circular,  and  that  of  the  cava  infe- 
rior is  larger  than  that  of  the  cava  superior. 
The  right  margins  of  these  veins  are  continuous 
with  each  other ;  the  left  or  anterior  margins 
are  continuous  with  the  auricle,  which  in  fact 
appears  at  first  sight  to  be  formed  by  an  ex- 
pansion of  the  veins ;  hence  the  term  sinus 
venosus.  Around  the  left  margin  of  the  en- 
trance of  the  cava  superior  there  is  a  prominent 
band  of  muscular  fibres;  and  around  its  right 
and  posterior  margin  there  is  another  but  less 
prominent  band  placed  at  its  angle  of  junction 
with  the  right  margin  of  the  inferior  cava.  This 
last  band  occupies  the  position  of  the  sup- 
posed tubercle  of  Lower  ( tuberculum  Loweri ). 
The  cava  inferior  occasionally  forms  a  dilata- 
tion immediately  before  it  enters  into  the  au- 
ricle. The  venae  eavae  have  properly  no  valves 
at  their  entrance  into  the  auricles.*  The  fossa 
ovalis  (valvula  foraminis  ovalis,  vestigium  fo- 
raminis ovalis ),  which  marks  the  position  of 
the  foramen  ovale  by  which  the  two  auricles 
communicated  freely  with  each  other  in  the 
foetus,  is  seen  at  the  lower  and  right  portion  of 
the  auricle,  partly  placed  in  a  notch  in  the 
posterior  and  lower  part  of  the  fleshy  portion 
of  the  septum,  and  partly  in  the  upper  part  of 
the  vena  cava  ascendens  as  it  passes  in  to  form 
the  sinus  venosus.  The  upper  and  anterior 
margins  of  this  depression  are  thick  and  pro- 
jecting (annulus  seu  isthmus  Vieusseni,  columna 
foraminis  ovalis ).  This  was  supposed  by  Vi- 
eussens  to  prevent  the  blood  of  the  cava  supe- 
rior from  falling  into  the  cava  inferior,  an  effect 
which  Lower  also  imagined  might  be  produced 
by  the  tubercle  which  he  supposed  was  placed 
at  the  junction  of  the  two  veins.  We  have 
already  pointed  out  that  the  orifices  of  the  two 
veins  are  placed  in  different  directions,  which 
is  sufficient  to  prevent  the  descending  column 
of  blood  falling  directly  upon  the  ascending. 
The  posterior  and  lower  margins  of  the  fossa 
ovalis  are  ill-defined.  The  surface  of  the  de- 
pression is  sometimes  smooth,  at  other  times 
uneven  and  reticulated.  Between  the  upper 
margin  of  the  depression  and  the  annulus  or 
thickened  edge  of  the  fossa  ovalis  we  frequently 
find  a  small  slit  passing  from  below  upwards, 
and  forming  a  valvular  opening  between  the 
two  auricles.  The  remains  of  the  Eustachian 
valve  (foraminis  ovalis  anterior  valvula)  may 
be  seen  running  from  the  anterior  and  left  side 
of  the  entrance  of  the  cava  inferior  to  the  left 
side  of  the  fossa  ovalis,  where  it  attaches  itself 
to  the  annulus.  This  valve  exhibits  very  va- 
rious appearances  in  the  adult:  sometimes  it  is 
very  indistinctly  marked,  at  other  times  it  is 
sufficiently  apparent,  and  much  more  rarely  it 
approaches  the  size  which  it  presents  in  foetal 
life.    It  is  frequently  reticulated.    Its  convex 

*  The  Eustachian  valve  cannot  be  considered  as 
essentially  connected  with  the  cava  inferior  in  the 
adult. 


margin  is  attached  to  the  surface  of  the  vein 
and  auricle ;  its  concave  margin  is  free ;  its  su- 
perior and  convex  surface  looks  towards  the 
auricle,  and  its  lower  and  concave  surface  to- 
wards the  entrance  of  the  vein.  Placed  to  the 
left  of  the  Eustachian  valve,  and  between  it 
and  the  upper  and  outer  part  of  the  base  of  the 
ventricle,  is  the  orifice  of  the  coronary  vein.  A 
valve  ( valvula  Thcbesii ),  the  free  and  concave 
margin  of  which  is  directed  upwards,  covers 
the  entrance  of  this  vein.  It  is  sometimes  im- 
perfect, occasionally  reticulated.  Instead  of 
one  coronary  valve  we  may  have  two  or  more, 
one  placed  behind  another.  These  two  valves, 
viz.  the  Eustachian  and  Thebesian,  are  formed 
by  a  reduplicature  of  the  lining  serous  mem- 
brane of  the  heart. 

The  Eustachian  valve  frequently,  however, 
contains  some  muscular  fibres  at  its  fixed  mar- 
gin. A  number  of  small  openings  (foramina 
Thebesii)  may  be  seen  on  the  inner  surface  of 
the  auricle,  some  of  which  lead  into  depres- 
sions ;  others  are  the  orifices  of  small  veins. 
The  muscular  fibres  projecting  from  the  ante- 
rior and  outer  surface,  already  alluded  to,  pass 
vertically  from  the  auricle  to  the  edges  of  the 
auriculo-ventricular  opening.  These,  from  their 
supposed  resemblance  to  the  teeth  of  a  comb, 
are  termed  musculi  pectinati.  Smaller  bun- 
dles cross  among  the  larger,  giving  the  inner 
surface  at  this  part  a  reticulated  appearance. 
At  the  places  where  the  transverse  fibres  are 
deficient,  the  outer  and  inner  serous  mem- 
branes of  the  heart  lie  in  close  contact.  In  the 
floor  or  base  of  the  auricle  there  is  a  large  oval 
opening  leading  into  the  ventricle  (right  au- 
riculo-ventricular opening),  having  its  upper 
margin  surrounded  by  a  white  ring.  The  up- 
per part  of  this  ring  has  a  yellowish  colour 
from  the  auricular  tendinous  ring  being  here 
translucent,  so  that  the  fat  lying  in  the  auri- 
cular groove  is  seen  through  it. 

Right  ventricle  ( ventriculus  anterior,  v.  dex- 
ter, v.  pulmonalis.)  External  surf  ace. — The  right 
ventricle  occupies  the  anterior  and  inferior  por- 
tion of  the  right  side  of  the  heart.  Its  form  is 
pyramidal,  the  base  looking  towards  the  au- 
ricle, its  apex  towards  the  apex  of  the  heart. 
Its  walls  are  much  thicker  than  those  of  the 
auricle.  This  thickness  arises  from  the  in- 
creased number  of  its  muscular  fibres. 

Internal  surface. — The  right  ventricle  may 
be  best  opened  by  making  an  incision  along  its 
right  edge  from  the  base  to  the  apex,  and 
another  from  the  root  of  the  pulmonary  artery 
along  its  anterior  surface  near  the  septum  to 
join  the  other  at  the  apex.  On  examining  the 
interior,  its  internal  and  posterior  walls  are 
seen  to  be  common  to  it  and  the  opposite 
ventricle,  the  anterior  and  external  walls  to 
belong  exclusively  to  itself.  Its  posterior  and 
internal  walls  are  convex,  its  anterior  and 
internal  concave.  Its  posterior  and  external 
walls  are  decidedly  shorter  than  its  internal  and 
anterior.  Its  parietes  are  rather  thinner  at  their 
attachment  to  the  anterior  margin  of  the  septum 
than  along  its  posterior  margin.  They  are  also 
considerably  thinner  at  the  apex  than  towards 
the  'base.     A   number  of    fleshy  columns 


HEART. 


58  \ 


( columns  cameo,,  teretes  lacerti)  project  from 
the  inner  surface.  We  will  find  that  they 
present  three  different  appearances  in  both 
ventricles.  1.  The  more  numerous  are  attached 
to  the  .walls  of  the  ventricles  by  their  two 
extremities,  so  that  we  can  introduce  a  probe 
under  the  middle  part.  These  divide  and  sub- 
divide in  a  variety  of  ways.  2.  Others  are 
attached  to  the  walls  of  the  ventricles  by  the 
whole  of  their  external  surface,  while  their 
internal  surface  stands  in  relief  from  these  walls. 
3.  Others  are  fixed  to  the  walls  of  the  ventricle 
by  their  lower  extremities,  are  perfectly  free  in 
the  rest  of  their  course,  and  terminate  either 
in  a  blunt  extremity  or  in  several  short  pro- 
cesses. These  last  are  few  in  number,  nearly 
vertical,  and  have  received  the  name  of  musculi 
papillures.  These  columnae  carnese  form  an  in- 
tricate network  on  the  inner  surface  of  the 
ventricle,  and  some  of  them  occasionally  cross 
its  cavity  near  the  apex.  They  are  more 
numerous  on  the  anterior  and  external  than  on 
the  posterior  and  internal  walls.  Two  large 
openings  are  placed  at  the  base  of  the  ventricle. 
The  larger,  oval  in  the  empty,  somewhat  cir- 
cular in  the  distended  heart,  is  the  right 
auriculo-ventricular  opening,  the  upper  margin 
of  which  was  already  seen  in  the  right  auricle. 
The  smaller  is  circular,  is  placed  anterior  and 
to  the  left,  is  about  three-quarters  of  an  inch 
higher  than  the  larger,  and  is  the  orifice  of  the 
pulmonary  artery.  That  portion  of  the  ven- 
tricle from  which  the  pulmonary  artery  springs 
is  prolonged  upwards  above  the  level  of  the 
rest  of  the  ventricle.  To  this  prolongation 
Cruveilhier  has  given  the  name  of  the  infun- 
dibulum.* 

The  inner  surface,  particularly  the  posterior 
part  of  this  infundibulum,  is  smooth  and 
deprived  of  columnae  carnea-.  Around  the 
auriculo-ventricular  opening  a  valve  is  placed, 
the  fixed  margin  of  which  is  attached  to  the 
circumference  of  the  opening;  the  free  margin 
projects  into  the  ventricle.  This  valve,  which 
forms  a  complete  ring  at  its  attachment,  termi- 
nates in  several  apices,  three  of  which  are  much 
more  prominent  than  the  rest,  and  on  this 
account  it  receives  the  name  of  the  tricuspid 
or  triglochin  valve  (vulvulu  trigloclris  v.  tri- 
cuspis).  The  anterior  of  these  three  portions, 
which  is  placed  on  the  side  nearest  to  the  orifice 
of  the  pulmonary  artery,  is  more  prominent  and 
broader  than  the  posterior  and  internal  portions, 
and  is  separated  from  them  by  deeper  notches 
than  these  two  are  from  each  other.  From  this 
circumstance  some  are  inclined  to  consider  this 
valve  as  consisting  of  two  portions  only.  It 
contains  several  small  tubercles  at  its  free  margin. 

*  This  part  is  very  minutely  described  by  Wolff 
under  the  term  conns  arteriosus.  Under  the  term 
infundibulum  Wolff  included  a  larger  portion  oi  the 
ventricle,  apparently  that  portion  placed  above  a 
line  drawn  from  the  upper  and  right  margin  of  the 
ventricle  obliquely  downwards  to  the  anterior  fissure. 
As  the  upper  part  of  the  right  ventricle  becomes 
gradually  narrower,  he  supposed  that  it  increases 
the  velocity  and  impetus  of  the  blood  as  it  is  driven 
from  the  ventricle. — Acta  Acad.  Imper.  Petropol. 
pro  anno  1780,  torn.  vi.  p.  209.  1784. 


This  valve,  like  the  other  valves  at  the  arterial 
and  left  auricular  orifices,  to  be  afterwards 
described,  is  composed  of  a  reduplicatureof  the 
lining  membrane  containing  some  tendinous 
fibres  between  them.  It  is  translucent  and  of 
great  toughness.  A  number  of  tendinous  cords 
( chorda  tendinete )  pass  between  the  apices  of 
these  valves  and  the  inner  surface  of  the  ven- 
tricle. Though  the  arrangement  of  these  chordae 
tendineae  is  not  uniform  in  all  cases,  yet  it  is 
of  importance  to  remark,  as  prominently  bearing 
upon  the  discussions  connected  with  the  man- 
ner in  which  these  valves  at  the  auriculo-ven- 
tricular opening  perform  their  office,  that  their 
general  distribution  is  the  same,  and  evidently 
intended  for  a  specific  purpose.*  The  greater 
part  of  these  chordae  tendineae  spring  from  the 
free  and  blunt  extremities  of  the  third  kind  of 
columnae  carneae  (musculi  papillures )  which 
we  have  described  ;  some  from  the  other  two 
kinds,  and  others  again  from  the  smooth  portion 
of  the  septum,  and  more  particularly  from  the 
low;er  part  of  the  smooth  surface  which  leads 
into  the  infundibulum.  These  tendinous  cords 
diverge  to  reach  their  insertion,  some  of  them 
dividing  and  subdividing  two  or  three  times, 
occasionally  crossing  each  other,  and  are 
inserted  principally  into  the  apices  and  margins 
of  the  notches  which  separate  the  valve  into  its 
three  portions.  A  few  of  these  cords  pass 
between  the  columns  and  inner  surface  of  the 
ventricle  without  being  attached  to  the  valve. 
The  internal  lip  of  the  valve  has  its  lower 
margin  tied  more  closely  down  to  the  surface 
of  the  ventricle  by  these  cords  than  the  other 
two  lips  ;  besides  several  short  cords  frequently 
pass  between  the  internal  surface  of  the  ven- 
tricle and  the  ventricular  surface  of  that  portion 
of  the  valve.  At  the  exit  of  the  pulmonary 
artery  from  the  upper,  anterior,  and  left  part  of 
the  ventricle,  three  valves  are  placed  ( fig.  268). 
These  from  their  form  have  received  the  name 
of  semilunar  or  sigmoid  valves.  Their  fixed 
margins  are  convex, and  adhere  to  the  tendinous 
ring  to  which  the  origin  of  the  artery  is  attached  ; 
their  free  edges,  from  the  presence  of  a  small 
triangular  tubercle  in  the  middle  of  each  ( cor- 
pus Arantii,  corpusculum  Morgagni,  corpus 
sesamoideum,)  form  two  slight  semilunar  curves 
(fig.  268).  Theextremitiesof  the  curved  attached 
edges  look  in  the  course  of  the  artery.  When 
the  blood  rushes  from  the  ventricle  into  the 
pulmonary  artery,  the  valves  are  laid  against 
the  sides  of  the  vessel,  and  the  free  edge  becomes 
vertical ;  when,  on  the  other  hand,  a  portion  of 
the  blood  falls  back  towards  the  ventricle,  the 
valves  are  thrown  inwards  and  completely 
occupy  the  calibre  of  the  artery.  At  this  time 
the  concave  surfaces  of  the  valves  are  directed 
in  the  course  of  the  artery,  the  convex  surfaces 
towards  the  ventricle.  These  valves  may  be 
distinguished  by  the  terms  anterior,  posterior  or 
left,  and  superior  or  right.    The  suggestion  of 

*  Mr.  T.  W.  King  states  (Guy's  Hospital  Reports, 
no.  iv.  p.  123.)  that  there  is  a  disposition  in  the 
chordae  tendineae  from  each  fleshy  column  to  attach 
themselves  to  the  adjoining  edges  of  two  lips  of  the 
valve,  as  in  the  left  ventricle. 


582 


HEART. 


Fantonus,  tl>at  as  three  circular  valves  meeting 
in  the  axis  of  a  canal  would  leave  a  small  space 
in  the  axis  itself,  so  the  use  of  these  corpora 
Arantii  may  be  to  fill  up  the  interval  which 
would  thus  otherwise  be  left,  has  generally 
been  adopted.*  These  valves  are  thin  and 
transparent,  yet  of  considerable  strength.  Their 
attached  are  thicker  than  their  free  margins. 
That  portion  of  the  pulmonary  artery  which  is 
placed  immediately  above  the  attachment  of  the 
semilunar  valves  bulges  out  and  forms  three 
projections,  named  from  their  discoverer 
sinuses  of  Valsalva.  These  sinuses  are  more 
apparent  in  old  than  in  young  persons. 

Lef  t  auricle  ( auricula  sinistra ;  a.  pos- 
terior ;  atrium  seu  sinus  venarum  pulmonalium, 
a.  aortkum).  External  surface. — It  occupies 
the  upper,  posterior,  and  left  part  of  the  base  of 
the  heart,  and  receives  the  blood  brought  back 
from  the  lungs  by  the  pulmonary  veins.  The 
only  part  of  the  left  auricle  that  can  be  fairly 
seen  after  the  pericardium  has  been  opened, 
and  none  of  the  parts  disturbed,  is  the  appendix. 
To  see  it  properly  the  pulmonary  artery  and 
aorta  must  be  cut  through  and  thrown  forwards. 
It  is  of  a  very  irregular  shape,  some  anatomists 
comparing  it  to  an  oblong  quadrilateral,  others 
to  an  irregular  cuboidal  figure.  Posteriorly 
it  rests  upon  the  spinal  column,  from  which  itis 
separated  by  the  parts  mentioned  in  describing 
the  position  of  the  heart  itself,  and  appears  as 
if  confined  between  the  spine  and  base  of  the 
heart, — a  fact  which  has  been  considerably 
insisted  upon  in  some  of  the  explanations  of  the 
tilting  motion  of  the  heart.  Superiorly  and  to 
the  right  it  is  connected  to  the  auricle  of  the 
opposite  side.  More  anteriorly  and  still  to  the 
right  it  is  free,  and  is  separated  from  the  right 
auricle  by  the  aorta  and  pulmonary  artery.  lis 
base  is  connected  to  the  base  of  the  corres- 
ponding ventricle.  The  auricle  is  prolonged 
forwards  at  first  to  the  left,  but  bends  towards 
the  right  before  terminating.  This  prolongation 
is  the  appendix  or  proper  auricle.  This 
appendix  is  longer,  narrower,  more  curved, 
more  denticulated  on  the  edges,  and  more 
capacious  than  the  corresponding  part  of  the 
right  auricle,  and  projects  along  the  left  side  of 
the  pulmonary  artery,  a  little  beyond  and  below 
the  anterior  margin  of  the  left  ventricle.  The 
two  left  pulmonary  veins  enter  the  posterior 
and  left  side,  and  the  two  right  pulmonary 
veins  enter  the  posterior  and  right  side  of  the 
auricle. 

The  left  auricle,  like  the  right,  has  been 
divided  into  sinus  venosus  and  proper  auricle. 
Inner  surface. — The  inner  surface  may  be 
divided  into,  1st,  a  posterior,  which  is  smooth, 
and  which  belongs  exclusively  to  itself;  2d,  an 

*  I  find  that  the  late  Dr.  A.  Duncan,  jun.  has 
justly  remarked  that  there  is  no  necessity  for  calling 
in  the  aid  of  the  corpora  Arantii  to  produce  the 
complete  obstruction  of  the  calibre  of  the  artery,  as 
the  free  edges  of  these  valves,  when  they  are 
thrown  inwards,  do  not  exactly  lie  in  close  apposition 
but  overlap  each  other.  Besides  these  bodies  are 
occasionally  very  indistinct,  and  frequently  do  not 
project  beyond  the  free  margin  of  the  valves, 
especially  in  the  pulmonary  semilunar  valves. 


anterior,  which  communicates  by  a  round 
opening  with  the  cavity  of  the  appendix;  3d,  a 
right,  the  anterior  and  greater  part  of  which 
is  formed  by  the  septum  of  the  auricles.  Upon 
this  is  observed  the  fossa  ovalis,  but  without 
the  distinct  depression  which  it  presented  in 
the  right  auricle.  The  upper  margin  of  the 
valve,  between  which  and  the  upper  thick  edge 
of  the  fossa  ovalis  the  oblique  aperture  exists, 
which  we  formerly  stated  to  be  frequently 
observed  here,  is  often  distinctly  seen  in  the 
left  auricle.  The  valvular  nature  of  this  small 
slit  must  prevent  any  intermixture  of  the  blood 
of  the  two  sides.  This  margin,  when  present, 
looks  forwards  and  to  the  left.  The  two  right 
pulmonary  veins  open  upon  this  surface  imme- 
diately posterior  to  the  septum,  and  between 
the  septum  and  posterior  surface.  4th,  A  left, 
into  which  the  two  pulmonary  veins  of  the  left 
side  open. 

The  pulmonary  veins  of  the  two  lungs  are 
thus  separated  from  each  other  by  the  whole 
breadth  of  the  auricle.  The  veins  of  the  same 
side  open  into  the  auricle,  the  one  immediately 
below  the  other,  so  that  they  occupy  the  whole 
height  of  the  auricle.  The  superior  is  generally 
the  larger.  The  two  veins  of  the  same  side 
occasionally  enter  by  a  common  opening,  or 
this  may  occur  on  one  side  only.  At  other 
times  we  may  have  five  openings.  These  veins, 
like  the  cava;,  have  no  valves  at  their  termina- 
tion in  the  auricle.  At  the  lower  and  anterior 
part  of  the  auricle  a  large  oval  opening  presents 
itself.  This  is  the  left  auriculo-ventricular 
opening,  and  like  that  on  the  right  side  it  has 
its  upper  margin  surrounded  by  a  white  tendi- 
nous ring.  This  ring,  unlike  that  of  the  right 
side,  is  everywhere  sufficiently  opaque  to  pre- 
vent the  fat  placed  in  the  auricular  groove  to 
be  seen  through  it. 

The  inner  surface  of  the  left  auricle  differs 
materially  from  that  of  the  right  in  its  greater 
smoothness,  and  the  consequently  smaller  num- 
ber of  its  musculi  pectinati.  In  fact,  the  only 
place  in  which  these  are  observed,  and  that  too 
to  a  comparatively  smaller  extent  than  in  the 
corresponding  portion  of  the  right,  is  the  ap- 
pendix. This  arises  from  the  greater  strength 
of  the  left  auricle,  the  muscular  fibres  being  so 
closely  laid  together  as  not  to  leave  any  interval 
between  them. 

LeJ't  ventricle  (ventriculus  sinister,  v.  pos- 
terior, v.  aorticus.)  External  surface. — It  is 
of  a  conical  shape,  and  occupies  the  posterior 
and  left  part  of  the  heart.  It  is  rounded  and 
does  not  present  the  flattened  appearance  of 
the  right  ventricle.  It  projects  downwards 
beyond  the  right,  and  forms  the  apex  of  the 
heart.  Though  the  left  proceeds  lower  down 
than  the  right  ventricle,  that  portion  of  the  right 
called  infundibulum  or  conus  arteriosus  mounts 
higher  than  any  part  of  the  left.  The  left  is  on 
the  whole  a  little  longer  than  the  right.  The 
circumference  of  the  base  of  the  right  ventricle 
is  greater  than  that  of  the  left,  exceeding  it  in 
some  cases  in  the  injected  heart  by  about  two 
inches. 

Internal  surface.  —  This  ventricle  is  best 
opened  by  making  an  incision  close  upon  the 


HEART. 


388 


anterior  fissure  from  the  apex  near  to  the  com- 
mencement of  the  aorta,  then  another  in- 
cision midway  between  the  posterior  fissure 
and  left  edge  of  the  ventricle,  commencing  near 
the  base  and  carrying  it  downwards  to  join  the 
other  at  the  apex.  The  anterior  and  right 
parietes  of  the  internal  surface  are  formed  by 
the  septum  ;  the  posterior  and  left  belong  ex- 
clusively to  itself.  The  walls  of  the  left  ven- 
tricle are  considerably  thicker  than  those  of  the 
right,  and  remain  apart,  while  those  of  the  right 
fall  together.  As  connected  with  this  we  may 
observe  that  the  septum  is  concave  towards  the 
left  ventricle  and  convex  towards  the  right.  As 
the  obstacles  to  be  overcome  in  transmitting  the 
blood  through  the  body  are  greater  than  those 
to  be  overcome  in  transmitting  it  through  the 
lungs,  so  is  the  left  ventricle  thicker  than  the 
right.  It  is  important  to  remark,  as  connected 
with  the  pathology  of  spontaneous  rupture  of 
the  heart,  that  the  walls  of  the  left,  like  those 
of  the  right  ventricle,  are  considerably  thinner 
at  the  apex  than  towards  the  base.*  The  ante- 
rior and  right  parietes  are  longer  than  the  pos- 
terior and  left.  The  columns  may  be  arranged 
into  three  kinds,  such  as  we  have  described  in 
the  right  ventricle.  They  are  not  so  numerous 
in  the  left  ventricle  as  in  the  right.  The  greater 
number  are  also  smaller,  and  are  principally 
placed  upon  the  posterior  and  left  wall,  near  the 
apex  of  which  they  form  deep  areolae.f  The 
upper  part  of  the  septum  which  leads  to  the 
aortic  opening,  which  we  shall  presently  describe, 
is  quite  smooth.  In  the  base  of  the  ventricle 
we  find  two  openings  placed  closely  together ; 
one  of  these,  the  smaller,  is  placed  to  the  right 
and  a  little  anterior,  is  the  commencement  of 
the  aorta,  and  occupies  the  upper  and  right 
corner  of  the  ventricle  ;  the  other  is  larger  and 
placed  to  the  left  and  a  little  posterior,  and  is 
the  auriculo-ventricular  opening  of  this  side. 
The  aortic  opening  is  only  separated  from  the 
auriculo-ventricular  opening  by  the  tendinous 
ring,  and  from  the  orifice  of  the  pulmonary 
artery  by  the  upper  part  of  the  septum.  A 
valve  resembling  the  tricuspid  is  attached  to 
the  tendinous  ring  around  the  auriculo-ventri- 
cular opening,  which,  from  being  more  de- 
cidedly divided  into  two  lips,  is  termed  bicuspid, 
and  from  its  fanciful  resemblance  to  a  bishop's 
mitre  has  generally  received  the  name  of  mitral 
valve.  Like  the  tricuspid  it  forms  a  complete 
ring  around  the  margin  of  the  auriculo-ventri- 
cular opening.  The  anterior  lip  of  the  valve  in 
the  quiescent  state  of  the  heart  hangs  suspended 
between  the  auriculo-ventricular  opening  and 
the  origin  of  the  aorta,  and  is  considerably 
larger  and  more  moveable  than  the  posterior, 
which  is  smaller  and  more  limited  in  its  move- 

*  The  circular  arrangement  of  the  muscular 
fibres  around  the  apex  (Jig.  274  J  must  have  the 
effect  ot  rapidly  approximating  the  inner  surfaces 
of  the  ventricles  at  the  apex  during  their  systole, 
more  particularly  when  the  apex  is  elongated,  as  in 
the  heart  of  the  horse,  and  thus  prevent  the  pres- 
sure from  falling  upon  the  extremity  of  the  apex, 
where  it  is  very  weakly  protected. 

t  Laennec.  has  erroneously  stated  in  general 
terms  that  the  columnar  of  the  right  ventricle  are 
larger  than  those  of  I  he  left. 


merits.  The  mitral  valve  is  formed  in  the  same 
manner  as  the  tricuspid,  and  is  somewhat 
thicker  and  stronger,  and  like  it  contains  a 
number  of  tubercles  in  its  free  margin.  The 
large  anterior  lip  of  the  mitral  valve  projecting 
downwards  into  the  ventricle  was  described  by 
Lieutaud  and  by  others  since  his  time  as 
dividing  the  ventricle  into  two  portions,  an 
aortic  and  a  ventricular.  These  are  separated 
from  each  other  at  the  upper  part  by  the  valve 
only;  at  every  other  part  they  communicate 
with  each  other.  The  same  authors  have 
described  the  larger  lip  of  the  tricuspid  valve 
as  effecting  a  similar  division  of  the  pulmonic 
ventricle.  Two  of  the  columnar  carnea;  in  the 
left  ventricle  belong  to  the  third  kind  (musculi 
papillares)  already  described,  and  are  much 
stronger  than  any  to  be  found  in  the  right  ven- 
tricle. They  are  attached  to  the  lower  part  of 
its  cavity,  pass  upwards,  and  about  the  middle 
of  the  ventricle  terminate  in  a  blunt  extremity, 
from  which  a  number  of  chorda;  tendines  pass 
to  be  attached  to  the  margins  of  the  mitral 
valve.  Bouillaud  describes  these  two  columns 
as  uniformly  occupying  the  same  position,  one 
being  placed  at  the  junction  of  its  left  and 
posterior  walls  to  form  the  left  margin  of  the 
heart ;  the  other  on  the  posterior  wall  near  its 
junction  with  the  posterior  margin  of  the  sep- 
tum.* Each  of  these  fleshy  columns  consists 
of  two  fasciculi,  of  an  anterior  and  superior, 
and  of  a  posterior  and  inferior.  The  posterior 
and  inferior  fasciculus  is  shorter  and  less  strong 
than  the  anterior.  The  chordae  tendineae  of 
the  two  anterior  or  internal  fasciculi  proceed  to 
attach  themselves  to  the  margins  of  the  anterior 
or  larger  lip  of  the  valves,  those  from  one 
fasciculus  passing  to  one  edge  of  the  lip,  and 
those  of  the  other  fasciculus  to  the  other  edge. 
As  these  chorda;  tendinea;  proceed  from  the 
fasciculi  to  the  valve,  they  diverge  from  those  of 
the  same  fasciculus,  but  converge  towards  those 
of  the  other  fasciculus.  ( Fig.  2G9  shews  the 
attachment  of  the  chorda;  tendineue  of  the  two 
anterior  or  internal  fasciculi.)  The  chorda; 
tendineae  from  the  posterior  fasciculi  pass  in  a 
similar  manner  to  be  attached  to  the  posterior 
lip.  The  posterior  lip  is  fixed  closer  in  its 
situation  than  the  anterior,  by  the  chorda;  ten- 
dinea?, and  this  is  frequently  increased  by  some 
of  these  cords  passing  from  the  walls  of  the 
ventricle  to  be  attached  to  the  ventricular  sur- 
face of  the  valve,  sometimes  nearly  as  high  as 
the  fixed  margin  of  the  valve.  These  chordae 
tendineae  are  stronger,  fewer  in  number,  and 
less  subdivided  than  those  in  the  right  ventricle. 
Several  of  them  pass  between  the  fleshy  columns 
without  being  attached  to  the  valves,  as  in  the 
right  ventricle.  Though  the  description  here 
given  is  not  perfectly  uniform  in  every  case,  but 
is  liable  to  frequent  varieties, — by  the  non-divi- 

*  I  have  satisfied  myself  by  numerous  examina- 
tions, of  the  accuracy  of  Bouillaud's  account  of  the 
position  of  these  musculi  papillares  and  the  arraa^e. 
rnent  of  the  chorda;  tendineae  in  the  human  heart. 
I  have  found  them  occupying  a  similar  position  in 
the  heart  of  the  horse,  ox,  ass,  sheep,  pig,  do"-, 
rabbit,  hedge-hog,  and  some  birds,  and  suspeet 
that  this  will  be  found  a  general  law  in  all  th<j 
warm-blooded  animals. 


584 


HEART. 


sion  of  the  musculi  papillares  into  two  fasciculi ; 
by  their  subdivision,  on  the  other  hand,  into 
several  smaller  bundles,  but  so  grouped  that 
the  position  of  the  smaller  corresponds  to  the 
larger;  and  by  the  smaller  columns  furnishing 
a  certain  number  of  the  cords  usually  given  off 
by  the  larger;  yet  there  appears  to  be  a  remark- 
able similarity  between  the  course  and  arrange- 
ment of  the  chordre  tendineae  in  all  cases.  The 
object  of  this  we  will  afterwards  see  when 
inquiring  into  the  precise  manner  in  which 
these  valves  prevent  regurgitation  into  the  auricle 
during  the  systole  of  the  ventricle.  The  origin 
of  the  aorta  is  furnished  with  three  semilunar 
valves  (Jig.  269),  which  very  exactly  resemble 
in  their  position,  shape,  and  appearance  those 
placed  at  the  commencement  of  the  pulmonary 
artery.  They  are  somewhat  stronger,  and  have 
the  corpora  sesamoidea  generally  larger  than 
those  in  the  pulmonary  artery.  Behind  these 
valves  are  three  dilatations  ( sinuses  of'  Valsalva ) 
upon  the  commencement  of  the  aorta,  similar 
to,  but  more  prominent,  than  those  at  the  com- 
mencement of  the  pulmonary  artery  (Jig.  269). 

It  was  maintained  by  several  of  the  older 
eminent  anatomists  that  the  semilunar  valves 
must  necessarily  cover  the  entrance  of  the 
coronary  arteries,*  and  that  they  were  filled, 
not  during  the  passage  of  the  blood  along  the 
aorta,  but  by  the  falling  back  of  part  of  it 
during  the  diastole  of  the  heart,  or  as  Boer- 
haave  expressed  it,  "  Heb  arterise  sunt  in  dias- 
tole, dum  reliquae  corporis  arteriae  in  systole 
constitiiuntur."f  Haller  mentions  two  circum- 
stances which  must  satisfy  every  one,  if  any 
thing  more  than  the  bare  inspection  of  the  parts 
was  necessary,  that  the  coronary  arteries  are  at 
least  generally  filled  in  the  same  manner  as  the 
other  arteries  which  arise  from  the  aorta,  and 
these  are — 1st,  the  result  of  experiments  on 
living  animals,  where  the  blood  is  seen  to  spring 
per  saltum  from  the  cut  coronary  arteries  during 
the  systole  of  the  heart;  2d,  when  a  fatus  is 
injected  by  the  umbilical  vein,  the  coronary 
arteries  are  also  filled.  More  lately,  however, 
VaustJ  has  maintained  that  the  origin  of  the 
coronary  arteries  is  generally  covered  by  the 
semilunar  valves.  He  states  that  he  has  injected 
a  great  number  of  hearts  from  the  pulmonary 
veins;  in  some  of  these  the  injection  passed 
into  the  coronary^ arteries,  but  in  by  much  the 
greater  number  these  vessels  did  not  contain  a 
single  drop  of  injection.  On  examination  of 
these  cases  he  found  that  the  semilunar  valves 
entirely  covered  the  origin  of  the  coronary 
arteries.  In  attempting  to  ascertain  this  point 
on  the  uninjected  heart,  we  must  bear  in  mind 
the  different  conditions  of  the  aorta  in  the  living 
body  and  after  death.  In  the  dead  body  the 
sinuses  of  Valsalva  are  collapsed,  so  that  the 
semilunar  valves  can  be  laid  over  the  origin  of 
the  coronary  arteries  in  some  cases,  where  they 

*  Morgagni  was  doubtful  in  this  matter,  and 
thought  that  he  had  observed  them  sometimes 
covered  by  the  valves,  at  other  times  free.  Advers. 
v.,  Animadver.  xxv. 

t  Institut.  Med.  183. 

\  Recherches  sur  la  Structure  ct  les  Mouvements 
du  Cceur,  p.  22,  (1821.) 


would  become  free  when  the  sinuses  are  dis- 
tended as  they  axe  with  blood  in  the  living 
body.  Making  every  allowance  for  this  source 
of  fallacy,  I  am  satisfied  that  I  have  seen  one 
or  two  cases  in  which  these  valves  appeared 
fairly  to  cover  the  origin  of  the  coronary  arteries. 
Supposing  that  the  origin  of  the  coronary 
arteries  were  covered  in  some  instances  by  the 
valves,  it  would  in  all  probability  be  a  matter 
of  little  moment,  as  far  as  the  efficiency  of  the 
circulation  through  these  arteries  was  concerned, 
as  long  as  the  aorta  retained  its  elasticity,  for 
the  force  with  which  it  drives  the  distending 
fluid  backwards  during  the  diastole  of  the 
heart  (a  force  which  can  be  ascertained  in  the 
dead  body)  would  be  sufficient  to  carry  on  the 
circulation.  The  circumstances  would,  how- 
ever, become  very  much  altered  in  those  cases 
which  are  sufficiently  common  in  advanced 
age,  where  the  aorta  has  from  disease  of  its 
coats  entirely  lost  its  elasticity,  and  the  coronary 
arteries  have  also  become  studded  with  calca- 
reous matter,  unless  we  suppose  what  could 
scarcely  happen,  that  the  blood  contained  in  the 
sinuses  is  forced  along  the  arteries  when  the 
valves  are  thrown  outwards.* 

Septum  of  the  ventricles. — The  septum  be- 
tween the  ventricles  is  triangular,  and  the  apex 
extends  to  the  point  of  the  heart.  It  is  of 
considerable  thickness  at  the  base,  but  becomes 
thinner  at  the  apex.  Its  position  is  oblique 
like  that  of  the  heart.  It  is  concave  towards 
the  right  ventricle,  and  convex  towards  the  left. 
From  the  slight  rotation  of  the  heart  on  its 
axis,  the  anterior  surface  of  the  septum  is 
directed  towards  the  right  side,  and  the  posterior 
towards  the  left.  It  is  composed,  like  the  other 
walls  of  the  ventricle,  principally  of  muscular 
fibres,  lined  on  the  one  side  by  the  internal 
serous  membrane  of  the  right  ventricle,  and  on 
the  other  side  by  the  corresponding  membrane 
of  the  left. 

We  have  preferred  considering  the  relative 
thickness  of  the  parietes,  the  different  capacities 
of  the  several  cavities  of  the  heart,  the  relative 
dimensions  of  the  auriculo-ventricular,  aortic, 
and  pulmonary  orifices,  and  the  size  and  weight 
of  the  heart  under  distinct  heads,  not  only  as 
this  enables  us  to  obtain  a  more  connected 
view  than  we  could  otherwise  have  done  of 
points  upon  which  there  are  many  conflicting 
opinions,  and  upon  which  it  is  so  frequently 
necessary  to  possess,  as  far  as  we  possibly  can, 
accurate  notions  in  deciding  upon  the  normal 
or  abnormal  state  of  the  organ,  but  we  were 
also  afraid  that  if  mixed  up  with  the  other  parts 
of  the  descriptive  anatomy  they  would  have 

*  Among  the  numerous  and  striking  examples 
which  the  history  of  medical  science  furnishes  us 
of  the  powerful  tendency  which  preconceived 
notions  have,  if  not  powerfully  guarded  against, 
of  influencing  our  observations  of  the  plainest  facts, 
we  may  instance  the  statements  of  Petriolus  on  this 
question.  He,  apparently  deeply  imbued  with  the 
old  hypothesis  that  the  heart  is  the  seat  of  courage, 
maintained  that  in  bold  and  carnivorous  animals 
the  coronary  arteries  were  above  the  valves;  in 
timid  and  herbivorous  animals,  on  the  contrary, 
they  arose  behind  the  valves,  while  in  man  they 
were  of  uncertain  origin,  as  he  was  bold  or  timid. 


HEART. 


585 


rendered  it  more  complicated.  We  will  find 
that  considerable  differences  in  these  respects 
may  exist  between  different  hearts  and  between 
different  parts  of  the  same  heart,  which,  to 
judge  from  the  perfect  regularity  with  which  all 
Us  functions  proceeded  before  death,  must  be 
considered  as  perfectly  healthy ;  and  it  is  from 
this  want  of  uniformity  in  the  different  parts  of 
apparently  healthy  hearts  that  we  can  in  some 
measure  account  for  the  discrepant  statements 
on  this  subject  which  exist  in  the  works  of  the 
most  celebrated  and  accurate  anatomists. 

Thickness  of  the  walls  of  the  several  cavities 
of  the  heart. — The  left  auricle  is  somewhat 
thicker  than  the  right,  and  the  left  ventricle 
very  considerably  thicker  than  the  right.  Bouil- 
laud* found  the  average  thickness  of  the  walls 
of  the  left  auricle  in  four  healthy  hearts  to  be 
1£  lines,  and  that  of  the  right  auricle  to  be 
1  line.  Lobstein  has  rather  strangely  staled 
that  the  right  auricle  is  twice  the  thickness 
of  the  left.  He  makes  the  thickness  of  the 
right  auricle  to  be  1  line,  and  that  of  the  left 
to  be  only  \  line.  Laennec  reckons  the  relative 
proportion  of  the  thickness  of  the  left  ventricle 
to  the  right  as  rather  more  than  2  to  1. 
Bouillaud  found  the  average  thickness  of  the 
right  ventricle  at  its  base  in  a  great  number 
of  cases  to  be  2J  lines,  and  that  of  the  left 
ventricle  at  the  same  part  to  be  7  lines. 
Cruveilhierf  states  the  proportionate  thickness 
of  the  right  to  the  left  ventricle  as  1  to  4, 
or  even  as  1  to  5.  According  to  Soetnmerring,J 
the  relative  thickness  of  the  two  ventricles 
is  as  1  to  3.  Andral§  states  that  in  the  adult 
the  thickness  of  the  left  to  the  right  ventricle 
is  as  2  to  1,  but  in  infancy  and  in  old  age 
it  is  as  3  or  4  to  1. 

M.  Bizot  has  lately  published  the  results 
of  the  careful  measurements  of  the  healthy 
heart  in  one  hundred  and  fifty-seven  indivi- 
duals of  all  ages. ||  The  greater  part  of  these 
observations  were  collected  at  La  Pitie,  under 
the  auspices  of  Louis.  According  to  M.  Bizot, 
the  heart  goes  on  increasing  in  all  its  dimen- 
sions— length,  breadth,  and  thickness — up  to 
the  latest  periods  of  life.  The  growth  is, 
however,  more  rapid  before  twenty-nine  years 
than  after  that  age.  While,  then,  the  muscles 
of  animal  life  are  diminishing  in  size  in  ad- 
vanced life,  the  heart  is  still  increasing  in 
bulk.  The  heart  of  the  male  is,  on  an  average, 
larger  than  that  of  the  female  at  all  the  different 
stages  of  life.  M.  Bizot  remarks  that  the 
longitudinal  section  of  the  left  ventricle  is 
fusiform,  the  thickest  part  being  situated  at 
the  junction  of  the  superior  third  with  the 
middle  third.K  The  thickness  of  this  ventricle 
goes  on  increasing  from  youth  up  to  advanced 
age.    The  following  are  a  few  of  the  measure- 

*  Traite  Clinique  des  Maladies  du  Coeur,  t.  i. 
p.  53.  1835. 

t  Anatomie  Descriptive,  t.  iii.  p.  17. 

X  De  Corporis  Huraani  Fabrica,  t.  v. 

S  Anatomie  Pathologique,  t.  ii.  p.  283. 

||  Memoires  de  la  Societe  Medic.  d'Observation 
de  Paris,  t.  i.  p.  262.  1836. 

f  Op.  cit.  p.  269  and  284. 


ments  of  the  thickness  of  the  walls  of  the 
ventricles  given  by  M.  Bizot. 

Left  ventricle,  male. 
Age.  Base.  Middle  part.  Apex. 

1  to  4  years  ....    3  lines.  2f5  lines.  1$,  line. 
50  to  79  years  .  .     4fi  „      5§§    „      4£  „ 
Average  from  16  J  .„.,        ,  19  095 
to  79  years  .  .  S    m "       722  "        ™  " 
Left  ventricle,  female. 
1  to  4  years  ....    2-^lines.  2|lines.  2-t1B  lines. 
50  to  89  years  .  .     4i    „     5    „      3|  „ 
Average  from  16}  .3  .4  „13 

to  89  years  . .  J  8  "  5  "  3u  " 
Thickness  of  right  ventricle. — The  thickest 
portion  of  the  right  ventricle  is  not  placed, 
as  M.  Bizot  remarks,  at  the  same  point  as 
in  the  left.  In  the  right  ventricle  it  is  at  the 
base  of  the  heart,  4  lines  below  the  tendinous 
ring.  The  thickness  of  the  walls  of  the  right 
ventricle,  unlike  the  left,  remains  more  nearly 
stationary  at  the  different  periods  of  life.  They 
are,  however,  a  little  thicker  in  advanced  age 
than  at  an  earlier  period  of  life. 

Right  ventricle,  male. 
Age.  Base.  Middle  part.  Apex. 

1  to  4  years  ....      f0  line.    ^  line.    ,%  line. 


1 39 

liS  " 

1  "3 

^  1Tt  i  r> 


1& 


1  9 


■IS  » 
81 

ST  v> 


1TB  line. 

n 


me. 

31  " 


2* 
25 
57 

1 

m 


30  to  49  years  . . 
50  to  79  years  . . 
Average  from  16  ) 
to  79  years 

Right  ventricle,  female. 
1  to  4  years  ....  lfB  line.  I  line.  Jj|  line. 
30  to  49  years  , 
50  to  79  years  .  \\ 
Average  from  15  }  j2 
to  59  years  . .  S  3 
Care  was  taken  to  make  all  these  measure- 
ments at  points  where  there  were  no  columnar 
carneae. 

The  thickness  of  the  septum  ventriculorum, 
according  to  Meckel,  is  11  lines  at  its  base. 
Bouillaud  obtained  the  same  results  in  the 
only  case  in  which  he  appears  to  have  measured 
the  thickness  of  the  septum.  M.  Bizot  has 
given  measurements  of  the  ventricular  septum 
at  six  different  periods  of  life,  from  which  I 
have  selected  the  following. 

Male.  Female. 
Age.  Middle  part.    Middle  part. 

1  to  4  years   3T'5  lines.       2f  lines. 

16  to  29  years....      4\}    „  4f}  „ 

50  to  79  years   5J     „  5$  „ 

The  thickness  of  the  septum  ventriculorum 
goes  on  increasing  in  thickness  from  infancy 
to  an  advanced  period  of  life. 

Relative  capacities  of  the  several  cavities. — 
The  most  conflicting  statements  exist  upon 
this  point,  and  we  find  it  perfectly  impossible 
to  come  to  any  satisfactory  decision.  Each 
cavity  of  the  heart  is  supposed,  when  mo- 
derately distended,  to  contain  rather  more  than 
two  ounces  of  fluid.  The  auricles  may  be 
safely  said  to  be  of  less  capacity  than  the 
ventricles ;  and  this  disparity  is  strikingly 
marked  in  the  larger  animals,  as  the  horse 
and  ox.  The  right  auricle  is  generally  allowed 
to  be  larger  than  the  left,  and  the  difference, 


586 


HEART. 


as  stated  by  Cloquet  and  Cruveilhier,  is  as 
5  to  4.  The  right  ventricle  is  generally  found 
larger  than  the  left  after  death.  This  difference 
has  been  very  variously  estimated  by  different 
anatomists.  Some,  as  Winslow,  Senac,  Haller, 
Lieutaudj*  and  Boyer,  have  maintained  that 
there  is  a  marked  disparity  between  the  capa- 
cities of  the  two  cavities,  while  Meckel, 
Laennec,  Bouillaud,  Portal,  and  others  be- 
lieved that  this  difference  is  to  a  smaller  extent. 
Lower  was  the  first  to  maintain  that  both 
ventricles  are  of  equal  size.  Sabatier,  Andral, 
and  others  have  supported  this  opinion  ;  while 
Cruveilhierf  states  that  he  has  satisfied  himself, 
from  comparative  injections  of  the  two  cavities, 
that  the  left  ventricle  is  a  little  larger  than 
the  right.  Gordon  has  occasionally  found 
both  ventricles  of  equal  size,  and  Portal  has 
seen  them  of  the  same  size  in  young  persons. 
Santoriniand  Michelattus  believed  that,  though 
the  capacity  of  the  left  ventricle  appears  a 
little  smaller  than  that  of  the  right,  yet  that 
the  superior  force  of  the  left  auricle  over  the 
right  dilates  the  left  ventricle  sufficiently  to 
render  it  equal  to  the  right. 

The  majority  of  anatomists,  however,  have 
always  maintained  that  the  capacity  of  the 
right  ventricle  is  greater  than  that  of  the  left, 
and  have  adduced  the  following  arguments  in 
support  of  this  opinion:  1,  that  the  right 
auricle,  right  auriculo-ventricular  orifice,  and 
origin  of  the  pulmonary  artery  are  larger  than 
the  auricle  and  corresponding  orifices  of  the 
opposite  side :  2,  that  when  both  ventricles 
have  been  filled  with  water,  mercury,  or  wax, 
more  of  these  substances  is  found  contained 
within  the  right  than  the  left :  3,  the  experi- 
ment of  LegalloisJ  shew  that  when  an  animal 
is  bled  to  death,  this  disparity  between  the 
size  of  the  ventricles  is  still  found.  Those 
who  maintain  that  the  capacity  of  these  two 
cavities  is  equal  do  so  on  the  following 
grounds: — 1,  that  as  the  walls  of  the  right 
ventricle  are  weaker  than  those  of  the  left, 
when  the  same  force  is  used  in  injecting  both, 
the  right  must,  as  a  matter  of  course,  be  more 
dilated  than  the  left.  2.  Sabatier  ingeniously 
suggested  that,  as  during  the  last  moments  of 
life  the  passage  of  the  blood  from  the  right  side 
of  the  heart  is  generally  impeded,  producing 
engorgement  of  that  side,  while  the  left  side 
was  generally  empty,  this  might  account  for 
the  greater  size  of  the  right  ventricle.  3. 
Sabatier  and  Weiss§  maintained  that  in  those 
cases  where  the  kind  of  death  was  such  that 
the  right  side  of  the  heart  could  not  be  en- 
gorged as  in  fatal  haemorrhage,  no  difference 
between  the  capacity  of  the  two  sides  could 

*  Memoires  de  l'Academie  Roy.  des  Sciences, 
t.  viii.  p.  561, 1754.  Lieutaud's  authority  is  some- 
times quoted  in  support  of  the  opinion  that  these 
cavities  are  of  equal  capacity. 

t  Anatomie  Descriptive,  t.  iii. 

|  Dictionnaire  des  Sciences  Med.  t.  v.  p.  436. 
These  experiments  were  performed  upon  dogs,  cats, 
guinea-pigs,  and  rabbits. 

§  De  dcxtro  cordis  ventriculo  post  mortem  am- 
plijre. 


be  observed.  4.  The  experiments  of  Sabatier, 
in  which,  after  tying  the  aorta  and  producing 
engorgement  of  the  left  side  of  the  heart, 
while  the  right  side  was  emptied  by  a  wound  . 
made  into  the  vena  cava  or  pulmonary  artery, 
the  left  ventricle  was  found  to  be  of  greater 
capacity  than  the  right. 

M.  Bizot  maintains  that  the  capacity  of  the 
ventricles  goes  on  increasing  from  youth  up 
to  old  age ;  and  that  this,  contrary  to  the 
opinion  of  Beclard,  is  not  so  rapid  in  old 
age  as  in  the  earlier  periods  of  life.-  The 
following  are  a  few  of  M.  Bizot's  measure- 
ments : — 

Left  ventricle,  male. 
Age.  Length.  Breadth. 

1  to  4  years   20  lines.       31  lines. 

50  to  79  years ....     36    „  56|  „ 

Average  from  15  to  )  „.M  ,  .  s 

79  years   $  6^  "  _  " 

Left  ventricle,  female. 

1  to  4  years   18^  lines.      29§  lines. 

50  to  79  years   31     „         49±  „ 

Average  from  15  to  )  „.  ,  .„23 

89  years   S     35  "  55  " 

Right  ventricle,  male. 

1  to  4  years   201  lines.     47§  lines. 

50  to  79  years ....    37±    „         87  „ 
Average  from  15  to)  „7M  o.,n 

79  years   S        "  m  " 

Rig/it  ventricle,  female. 
1  to  4  years   .....    18J  lines.     44J  lines. 

50  to  79  years   35{J   „        76  „ 

Average  from  15  to  )  „  . 

89  years   S         "  *  " 

Every  one  must  confess  that  the  right  ven- 
tricle is  generally  found  larger  after  a  natural 
death  in  the  human  subject  than  the  left ;  and 
it  appears  exceedingly  probable  that  these  two 
cavities,  in  the  healthy  state  of  the  organ, 
contain  different  quantities  of  blood  during 
life.  As  the  capacity  of  the  auricles  is  rather 
smaller  than  that  of  the  ventricles,  it  may 
be  asked  how  can  the  auricles  furnish  blood 
sufficient  to  distend  the  ventricles ?  We  shall 
afterwards  more  particularly  explain  that  the 
blood  passes  from  the  auricles  into  the  ven- 
tricles at  two  different  times  during  the  interval 
between  each  contraction,  viz.  at  the  moment 
of  its  relaxation,  and  again  during  the  con- 
traction of  the  auricles.  Various  attempts 
have  been  made  by  those  who  maintain  that 
the  right  side  of  the  heart  is  larger  than  the 
left,  to  explain  how  the  equilibrium  of  the 
circulation  can  be  maintained.  Ilelvetius* 
supposed  that  this  could  be  accounted  for 
by  the  diminution  which  the  blood  suffered 
in  passing  through  the  lungs  ;  and  in  proof 
of  this  he  erroneously  maintained  that  the 
pulmonary  arteries  were  larger  than  the  pul- 
monary veins.  Legallois  believed  that  this 
could  be  explained  (as  appears  very  probable) 
by  the  greater  size  of  the  right  auriculo-ven- 
tricular opening,  allowing  a  greater  reflux  of 
blood  back  again  into  the  auricle,  during  the 
systols  of  the  ventricles. 

*  Memoire  de  l'Acad.  Roy.  1718,  p.  285. 


HEART. 


587 


Relative  dimensions  of  the  auricula  -ven- 
tricular orifices,. — The  right  auricula-ventricular 
orifice  is  larger  than  the  left,  as  was  correctly 
stated  by  Portal.*  According  to  Cruveilhier, 
the  largest  diameter  of.  the  right  auriculo- 
ventricular  opening  which  is  antero-posterior 
is  from  16  to  18  lines,  and  its  smallest  diameter 
is  12  lines;  while  the  largest  diameter  of  the 
left  auriculo-ventricular  opening,  which  is  di- 
rected almost  transversely,  is  from  13  to  14, 
and  its  smallest  is  from  9  to  10  lines.  Bouillaud 
gives  the  results  which  he  obtained  from  the 
accurate  measurement  of  the  circumference  of 
these  two  openings  in  three  perfectly  healthy 
hearts.  The  average  circumference  of  the  left 
auriculo-ventricular  opening  was  3  inches 
63  lines  :  the  maximum  was  3  inches  10  lines, 
and  the  minimum  was  3  inches  3  lines.  The 
average  circumference  of  the  right  auriculo- 
ventricular  opening  was  3  inches  10  lines:  the 
maximum  was  4  inches,  and  the  minimum 
was  3  inches  9  lines. 

Circumference  of  the  aortic  and  pulmonary 
orifices. — The  circumference  of  the  aortic  and 
ventriculo  -  pulmonary  orifices  is  sometimes 
nearly  equal  ;  more  generally,  however,  the 
ventriculo-pulmonary  is  the  larger.  Bouillaud 
gives  the  following  measurements  of  these 
openings  taken  from  four  healthy  hearts  : — 
Average  circumference  of  the  aortic  opening, 
2  inches  5J  lines:  the  maximum  2  inches 
8  lines,  and  the  minimum  2  inches  4  lines. 
Average  circumference  of  the  ventriculo-pul- 
monary opening,  2  inches  7|  lines :  the 
maximum  2  inches  10  lines,  and  the  minimum 
2  inches  6  lines.  I  have  found  this  difference 
between  the  circumference  of  these  two  open- 
ings marked  distinctly  at  seven  years  of  age. 
M.  Bizot  has  given  measurements  of  the  ar- 
terial orifices,  of  which  the  following  is  the 
average. 

Aortic  orifice,  male. 
Average  from  16  to  79  years. .  45^-  lines. 

Aortic  orifice,  female. 

Average  from  16  to  89  years  . .  413  lines. 
Pulmonary  orifice,  male. 

Average  from  16  to  79  years  . .  54Jf  lines. 
Pulmonary  orifice,  female. 

Average  from  16  to  89  years  . .  48^  lines. 

Size  and  weight. — Laennec  has  stated  that 
the  size  of  the  heart  in  general  nearly  corre- 
sponds to  the  closed  fist  of  the  individual. 
This  can  only  be  considered  as  a  loose  ap- 
proximation, as  the  size  of  the  hand  may  vary 
in  different  individuals  otherways  resembling 
each  other,  either  from  original  conformation 
or  from  dissimilar  modes  of  life  ;  and.,  besides, 
the  size  and  form  of  the  healthy  heart  itself 
may  vary  sufficiently  to  effect  an  apparent 
difference  in  these  respects. 

The  average  length  of  the  heart,  according 
to  Meckel,  is  5J  indies,  of  which  about 
4  inches  are  to  be  allowed  for  the  ventricles, 
and  \  \  inch  for  the  auricles.  Bouillaud  found 
that  a  line  drawn  from  the  origin  of  the  aorta 
to  the  point  of  the  heart  ranged,  in  nine 

*  Anatomie  Medicalc,  t.  iii.  p.  69. 


healthy  hearts,  from  4  inches  to  3  inches 
2J  lines.  The  average  length  was  3  inches 
7J  lines. 

The  weight  of  the  heart,  according  to 
Meckel,  is  about  10  ounces,  and  its  propor- 
tionate weight  to  the  whole  body  is  as  1  to  200. 
Tiedemann  is  of  opinion  that  the  proportionate 
weight  of  the  heart  to  the  body  is  as  1  to 
1-60.*  The  weight  of  the  healthy  and  empty 
heart,  according  to  Cruveilhier,  is  from  7  to 
8  ounces.  Bouillaud  found  the  average  weight 
in  thirteen  healthy  hearts  to  be  8  ounces 
3  drachms.  According  to  Lobstein  it  weighs 
between  9  and  10  ounces.  The  size  and 
weight  of  the  heart  must  generally  be  to  a 
great  extent  in.  conformity  with  the  size  and 
weight  of  the  body.  In  an  athletic  male  we 
would  expect  it  to  weigh  about  10  ounces,  in 
an  ordinary-sized  individual  about  8  ounces, 
and  in  weakly  persons,  or  in  cases  of  pro- 
tracted debility,  it  would  be  still  more  dimi- 
nished in  weight.  For  the  same  reason  it  is 
generally  larger  and  heavier  in  males  than 
in  females. 

Structure  of  the  heart. — The  heart  consists 
of  muscular  and  tendinous  textures,  of  cellular 
tissue,  of  bloodvessels,  of  nerves,  and  of  lym- 
phatics, enclosed  between  two  serous  mem- 
branes. 

Tendinous  texture.- — The  tendinous  texture 
of  the  heart  is  placed,  1,  around  the  auriculo- 
ventricular  and  arterial  orifices;  2,  within  the 
reduplicature  of  the  lining  membrane  forming 
the  auriculo-ventricular  and  arterial  valves ;  3, 
it  forms  the  chorda?  tendinea?. 

Auriculo-ventricular  tendinous  rings. — 
Around  each  auriculo-ventricular  opening  we 
find  a  tendinous  circle  or  ring,  from  the  upper 
part  of  which  the  muscular  fibres  of  the  au- 
ricles arise,  and  from  the  lower  part  those  of 
the  ventricles,  thus  affording  perhaps  the  only 
example  in  the  human  body  of  a  strictly  in- 
voluntary muscle  having  tendinous  attach- 
ments. The  tendinous  ring  surrounding  the  left 
auriculo-ventricular  opening  is  stronger  than 
that  surrounding  the  right.  These  tendinous 
zones  are  thicker  along  the  lower  edge  where 
the  muscular  fibres  of  the  ventricle  are  attached, 
and  become  thinner  along  the  upper  edge  where 
the  muscular  fibres  of  the  auricles  are  attached, 
so  that  the  fat  occupying  the  auricular  groove 
is  seen  through  the  upper  portion  of  the  ring 
on  the  right  side.  The  right  margin  of  the  left 
auriculo-ventricular  ring  is  connected  with  that 
surrounding  the  aortic  opening.  The  existence 
of  the  auriculo-ventricular  and  arterial  tendi- 
nous rings  was  well  known  to  Lower.f 

Arterial  tendinous  rings. — The  form  of  the 
tendinous  rings  surrounding  the  arterial  open- 
ings, and  the  manner  in  which  the  large  arte- 
ries are  attached  to  their  upper  edges,  have  not, 
I  think,  been  described  with  sufficient  accu- 
racy.  These  textures  are  very  plainly  observed 

*  If  wc  consider  the  ordinary  weight  of  an  adult 
heart  to  be  8  ounces,  and  the  average  weight  of 
the  whole  body  to  be  150  lbs.  the  proportionate 
weight  of  the  heart  to  the  body  would  be  as  I 
to  225. 

f  Tractatus  De  Corde,  p.  29.  1669. 


588 


HEART. 


in  the  heart  of  the  ox  and  horse  after  a  little 
dissection.  The  following  description  is  drawn 
up  from  numerous  dissections  of  these  parts 
made  on  the  human  heart.  The  tendinous  ring 
surrounding  the  aortic  opening  is  stronger  and 
thicker  than  that  surrounding  the  orifice  of  the 
pulmonary  artery.  Both  of  them  are  stronger 
than  the  auriculo-ventricular  rings.  Each  of 
the  arterial  rings  appears  as  if  composed  of 
three  semilunar  portions  placed  on  the  same 
plane,  the  convexities  of  which  are  turned 
towards  the  ventricles  and  the  concavities  to- 
wards the  vessels  (fig.  266,  a  a ')*    Each  of 


Fig.  266. 


Appearance  of  tendinous  ring  at  the  origin  of  the 
pulmonary  artery.  In  slitting  open  the  artery, 
one  of  the  three  projecting  extremities  of  tlie  ten- 
dinous ring  has  been  divided. 

these  semilunar  portions  has  its  projecting  extre- 
mities intimately  blended  at  their  terminations 
with  the  corresponding  projecting  extremities 
of  those  next  to  it,  (Jig.  266,  b  b,)  so  that  the 
three  form  a  complete  circle,  with  three  trian- 
gular portions  projecting  from  its  upper  edge. 
The  semilunar  portions  approach  fibro-carti- 
lage  in  their  structure,  and  have  the  intervals 
left  between  their  convex  edges  filled  with  a 
texture  more  decidedly  fibrous,  (fig.  266,  d,) 
and  which  is  considerably  weaker  than  the  se- 
milunar portions,  more  particularly  on  the  left 
side  of  the  heart. f  The  thinness  of  the  ten- 
dinous structure  filling  up  these  intervals  has 
led  some  anatomists  erroneously  to  describe 
these  portions  of  the  heart  as  protected  only 
by  the  two  serous  membranes.  The  right  ten- 
dinous zone  is  broader  than  the  left  and  very 
thin,  particularly  at  its  inner  margin,  at  which 
part  in  both  sides  of  the  heart  it  assumes  more 
of  the  tendinous  than  of  the  fibro-cartilaginous 
structure.  These  tendinous  rings  are  placed 
obliquely  from  without  inwards  and  from  above 
downwards,  so  that  the  outer  edge  is  on  a  plane 
superior  to  the  inner.  The  sigmoid  valves  are 
attached  to  the  inner  edge  of  the  upper  surface, 
(fig.  267,  a,)  and  the  tendinous  fibres  placed 
in  the  fixed  margins  of  these  valves  contribute 
to  the  thickening  of  the  ring  at  this  part ;  the 
middle  coat  of  the  arteries  is  connected  to  the 
outer  edge  of  the  same  surface,  and  to  the  an- 
terior part  of  the  projecting  extremities,  (fig. 
267,  b ;)  while  the  muscular  fibres  of  the  ven- 
tricles (fig.  266,/;  fig.  267,  f})  are  attached 
to  the  lower  surface  of  the  projecting  portion 
of  the  convexity,  and  to  the  lower  margin  of 
the  fibrous  tissue  filling  up  the  space  between 
the  convexities  of  the  projecting  ends,  (fig. 

*  These  tendinous  festoons  are  represented 
stronger  in  the  woodcut  than  they  are  naturally. 

t  These  intervals  are  occupied  by  muscular  librcs 
in  the  heart  of  the  ox  and  horse. 


Fig.  267. 


Pulmonary  artery  slit  open  at  its  origin,  its  internal 
membrane  stripped  off,  and  two  of  tite  sigmoid  valves 
completely  removed. 


a  a  a,  tendinous  festoons. 

b  b,  muscular  fibres  of  the  right  ventricle. 

c  c  c,  middle  fibrous  coat  of  the  artery  after  the 
internal  serous  membrane  has  been  stripped  off. 

g,  small  portion  of  one  of  the  semilunar  valves 
left  to  show  its  attachment  to  the  inner  edge  of  the 
upper  surface  of  the  tendinous  festoon. 

267,  d.)  There  is,  however,  this  difference 
between  the  right  and  left  arterial  openings 
with  respect  to  the  attachment  of  the  muscular 
fibres;— on  the  right  side  the  muscular  fibres 
arise  from  the  projecting  portion  of  the  con- 
vexity of  the  whole  three  tendinous  festoons, 
(fig.  268,  c,  c,)  while  in  the  left  side  the  mus- 

Fig.  268. 


cular  fibres  are  attached  only  to  one  and  part 
of  a  second,  (fig.  269,  b  b,)  as  the  larger  lip 
of  the  mitral  valve  (fig.  269,  a )  is  suspended 

Fig.  269. 


HEART. 


589 


from  the  posterior  orleft^  and  a  great  part  of  the 
anterior, — in  fact  to  that  part  of  the  tendinous 
ring  which  separates  the  aortic  from  the  auri- 
culo-ventricular  opening.  From  the  posterior 
part  of  that  portion  of  the  tendinous  ring  to 
which  the  mitral  valve  is  connected,  the  ante- 
rior fibres  of  both  auricles,  near  the  septum, 
arise.  As  the  left  tendinous  ring  is  thicker  and 
narrower  than  the  right,  there  is  a  larger  space 
left  between  the  fixed  edge  of  the  valves  and 
the  attachment  of  the  middle  coat  of  the  arte- 
ries than  there  is  on  the  left  side.  This  space 
is  of  some  importance,  as  upon  it  a  consider- 
able part  of  the  pressure  of  the  column  of 
blood  in  the  large  arteries  must  be  thrown 
during  the  diastole  of  the  ventricles. 

There  is  a  good  representation  of  these  ten- 
dinous rings  given  in  Tab.  II.  Opera  Valsalvae, 
torn.  i.  At  page  129  they  are  thus  described  : 
"  In  horum  sinuum  ambitu  qua  valvulae  si- 
nubus  annectuntur  quidem  quasi  Agger  videtur 
occurrere  substantias  durioris  ad  similitudinem 
cartilaginis  tarsi  palpebrarum."  I  find  also 
that  Gerdy*  appears  to  have  had  an  accurate 
notion  of  the  form  and  appearance  of  these  ten- 
dinous rings.  He  was  aware  of  the  existence 
of  the  projecting  angles  of  the  tendinous  ring 
which  pass  up  between  the  festoons  of  the 
middle  coat  of  the  arteries,  and  which  have 
been  overlooked  m  succeeding  descriptions.  I 
find  also  that  the  late  Dr.  A.  Duncan,  jun.  has, 
in  his  unpublished  manuscript,  given  a  very 
accurate  account  of  these  structures  in  the  heart 
of  the  ox. 

Tendinous  structure  in  the  auricula-ventri- 
cular valves. — Distinct  tendinous  fibres  exist 
in  the  auriculo-ventricular  valves  enclosed  be- 
tween the  reduplication  of  the  lining  serous 
membrane.  These  are  continuous  with  the 
auriculo-ventricular  tendinous  zones,  and  are 
most  distinct  and  of  great  strength  at  the  base. 
I  could  never  observe  any  distinct  traces  of  mus- 
cular fibres  in  these  valves  in  the  human  heart 
either  when  fresh  or  after  long  boiling.  Bouil- 
laud  has,  from  the  examination  of  one  incon- 
clusive case,  but  principally  from  analogy  with 
the  corresponding  valves  of  the  heart  of  the  ox, 
supposed  that  they  may  exist  in  some  cases  in 
hypertrophy  of  the  valves.  In  making  exami- 
nations of  this  kind  we  must  be  exceedingly 
careful  not  to  mistake  the  tendinous  fibres 
when  tinged  with  blood  for  muscular  fibres, 
for  under  these  circumstances  they  certainly  at 
all  times  assume  the  appearance  of  muscular 
fibres  .f 

*  Journal  Complementaire,  torn.  x. 

t  In  the  heart  of  the  dog  1  have  seen  a  distinct 
band  of  transverse  muscular  fibres  in  the  base  of 
the  larger  lip  of  the  mitral  valve,  but  could  never 
satisfy  myself  of  the  existence  of  any  longitudinal 
muscular  fibres.  In  the  heart  of  the  ox  and  horse 
very  distinct  longitudinal  muscular  fibres  are  seen 
in  the  valves  of  both  sides  of  the  heart,  princi- 
pally, if  not  entirely,  continuous  with  the  inner 
layer  of  the  fibres  of  the  auricles.  A  greater  part 
pass  over  the  inner  surface  of  the  tendinous  rings, 
and  are  firmly  attached  to  the  tendinous  structure 
of  the  valves,  reaching  nearly  to  the  lower  margin 
of  the  smaller  segments  of  the  valves.  The  effect 
of  these  fibres  upon  the  movements  of  the  valves 
would  form  an  interesting  subject  of  investigation. 


Tendinous  structure  in  the  arterial  valves. — 
Distinct  tendinous  fibres  also  exist  in  the  arte- 
rial valves,  which  must  add  considerably  to 
their  strength  and  prevent  their  more  frequent 
rupture.  Three  of  these  tendinous  bands  in 
each  valve  are  stronger  than  the  others,  and 
their  position  deserves  attention,  as  they  are 
often  the  seat  of  disease.  One  of  these 
bands  occupies  the  free  margin  of  the  valve, 
and  passes  between  the  projecting  extremities 
of  the  tendinous  festoons  (fig.  270,  a ).  Upon 
the  middle  of  this  band  the  corpus  Arantii, 
which  is  formed  of  a  similar  texture,  is  placed. 
The  other  band  comes  from  a  point  a  little 
above  the  middle  of  the  projecting  end  of  the 
tendinous  festoon  (fig.  270,  b ),  and  passes 
up  in  a  curved  manner  towards  the  corpus 
Arantii,  leaving  between  it  and  the  superior 
band  a  triangular  space  on  each  side,  in  which, 
if  any  tendinous  fibres  exist,  they  are  exceed- 
ingly obscure.  These  two  tendinous  bands 
were  well  known  to  Morgagni.  The  third 
band  is  placed  in  the  attached  margin  of  the 
valve,  and  renders  this  part  the  thickest  and 
strongest.  Between  the  middle  band  and  the 
attached  margin  of  the  valve  a  number  of 
weaker  bands  are  placed,  which  also  pass  up- 
wards, generally  assuming  a  curved  form.  Mor- 
gagni termed  these  lower  and  weaker  fibres  jibra 
carnea,  but  they  evidently  belong  to  the  same 
structure  as  the  stronger  bands.  The  arrange- 
ment of  these  tendinous  fibres  is  best  seen  in 
the  aortic  valves,  and  the  appearance  exhibited 
in  the  accompanying  representation,  (fig.  270,) 


Fig.  270. 


which  has  been  taken  from  Morgagni,  is  not 
always  distinctly  observed,  where  the  valves 
are  perfectly  healthy,  but  become  sufficiently 
obvious  in  certain  cases  of  disease. 


Attachment  of  the  middle  coat  of  the  arte- 
ries to  the  arterial  tendinous  rings. — The  inner 
and  outer  serous  membranes  are  continued  from 
the  heart  upon  the  arteries  ;  the  one  becoming 
the  inner  coat  of  the  arteries,  and  the  other  is 
continued  for  a  short  distance  upon  their  ex- 
ternal surface.  A  thin  layer  of  cellular  tissue 
also  passes  from  the  heart  along  the  arteries 
between  their  middle  coat  and  their  external 
serous  membrane.  These  are,  however,  so  far 
unimportant  compared  with  the  attachment  of  the 
middle  coat  of  the  arteries  to  the  tendinous  fes- 
toons which  we  have  just  described.  The  middle 
coat  is  so  very  firmly  and  strongly  attached  both 
to  the  external  edges  and  to  the  anterior  portion 
of  the  upper  part  of  these  projecting  extremi- 
ties, (fig.  267,  d,)  that  it  can  be  detached  with 
great  difficulty.  Those  fibres  of  the  middle 
coat  attached   to  the  projecting  extremities, 


590 


HEART. 


which  are  apparently  of  the  same  number  and 
thickness  as  in  that  portion  of  the  artery  im- 
mediately above,  form  a  distinct  curved  edge 
(fig-  267,  ej,  as  they  pass  from  the  extremity 
of  one  festoon  to  the  other.  As  we  trace  the 
middle  coat  of  the  artery  downwards  into  the 
concavities  formed  by  each  festoon,  we  find 
that  below  this  curved  edge  they  become  stri- 
kingly thinner  and  continue  to  diminish  in 
thickness  and  in  length,  (since  they  can  only 
stretch  between  the  projecting  extremities,) 
until  we  arrive  at  the  bottom  of  the  concavity. 
These  three  thin  portions  of  the  middle  coat 
must  then  be  placed  behind  the  semilunar 
valves,  and  correspond  to  the  sinuses  of  Val- 
salva.* The  thinness  of  the  middle  coat  at  the 
sinuses  of  Valsalva  will  render  this  portion  of 
the  artery  more  dilatable,  and  predispose  it 
to  rupture  when  its  coats  are  diseased. f  The 
tendinous  zones  are  distensible,  but  to  a  con- 
siderably less  extent  than  the  middle  coat  of 
the  arteries.  I  am  not  aware  that  this  account 
of  the  manner  in  which  the  middle  coat  of  the 
arteries  is  attached  to  the  tendinous  rings  has 
been  previously  given.  I  suspect,  however, 
that  Dr.  Duncan  must  have  been  perfectly 
aware  of  it  from  some  parts  of  his  manuscript. 
The  differences  between  these  tendinous  fes- 
toons and  the  yellow  elastic  coat  of  the  arteries, 
and  the  manner  of  their  attachment,  can  easily 
be  made  out  in  the  human  heart ;  they  are, 
however,  more  apparent  in  the  larger  animals, 
as  the  horse  and  ox.  The  different  characters 
of  the  two  tissues  are  obvious  at  the  first 
glance  after  boiling,  even  in  the  human  heart. 
Muscular  tissue.% — The  greater  part  of  the 

*  So  striking  is  the  difference  between  the  middle 
coat  as  it  fills  up  the  concavity  of  these  festoons, 
and  where  it  stretches  between  the  projecting  ex- 
tremities in  the  hedgehog,  that  at  first  sight  it  ap- 
pears to  be  deficient  at  that  part. 

t  According  to  Valsalva  aneurisms  are  frequently 
found  in  this  situation  :  *'sAtque  hie  aorta?  sinus 
maximus  ille  est,  in  quo  ssepe  anenrysmata  circa 
praecordia  contingunt,  ut  propria  obseivatione 
edoctus  sum."  Valsalva?  Opera.  Epist.  Anat. 
ed.  Morgagni,  torn.  i.  p.  131.  1740.  This  greater 
tendency  to  aneurismatic  dilatation  must  depend 
upon  two  circumstances.  The  increased  calibre  of 
the  artery  at  this  part  will  increase  the  pressure 
upon  its  walls  from  the  well-known  hydrostatic  law, 
that  "  in  a  quantity  of  fluid  submitted  to  compres- 
sion, the  whole  mass  is  equally  affected,  and  simi- 
larly in  all  directions,"  and  the  diminished  thick- 
ness of  the  middle  coat  will  materially  favour  this 
distending  force. 

%  While  I  was  engaged  in  examining  the  arrange- 
ment of  the  muscular  fibres  of  the  heart,  Dr.  Alison 
had  the  kindness  to  procure  for  me  the  manuscript 
of  the  late  Dr.  A.  Duncan,  jun.  on  this  subject.  It 
was  well  known  not  only  in  this  country  but  on  the 
continent  that  Dr.  Duncan  had  for  a  very  long  pe- 
riod attended  very  particularly  to  this  question,  and 
was  in  the  habit  of  demonstrating  the  parts  he  had 
ascertained  to  his  pupils.  Unfortunately  his  inten- 
tions of  publishing  on  the  subject  were  never  car- 
ried into  execution,  and  his  papers  referring  to  it 
were  left  in  so  confused  a  state  that  it  is  exceed- 
ingly difficult  and  in  most  parts  impossible  to  make 
out  the  description.  I  have  availed  myself  of  those 
parts  that  are  legible  in  the  following  pages,  and 
these  I  have  scrupulously  acknowledged.  Dr.  Dun- 
can's dissections  of  the  heart  were  taken  entirely 
from  the  ox  and  sheep. 


heart  is  composed  of  muscular  fibres  arranged 
in  a  very  intricate  manner.  These  fibres  are 
connected  together  by  cellular  tissue,*  which, 
however,  exists  in  much  smaller  quantity  in 
the  heart  than  in  the  other  muscles  of  the  body. 
These  fibres  are  attached  generally  by  both 
extremities  to  the  tendinous  rings  situated 
around  the  orifices  of  the  heart;  the  fibres  of 
the  auricles  pass  upwards  to  form  the  auricles, 
and  those  of  the  ventricles  downwards  to  form 
the  ventricles,  so  that  these  tendinous  rings 
must  form  the  fixed  points  towards  which  all 
the  contractions  of  the  heart  take  place.  None 
of  the  muscular  fibres  of  the  auricles  are  con- 
tinuous at  any  part  with  those  of  the  ventricles, 
and  we  will  find  that  while  some  of  them  are 
confined  to  a  single  auricle,  others  belong  to 
both.  In  the  same  manner  a  great  part  of 
the  fibres  of  the  ventricles  are  common  to 
both,  and  are  interwoven  together,  while  others 
again  belong  exclusively  to  a  single  ventricle, 
or,  as  Winslowf  expressed  it,  the  heart  is  com- 
posed of  two  muscles  enveloped  in  a  third. 
The  intimate  arrangement  of  these  muscular 
fibres,  particularly  those  of  the  ventricles,  is 
exceedingly  complex,  as  the  contraction  of  the 
organ  is  not  in  one  particular  direction  only, 
but  in  all  directions,  and  has  long  been  con- 
sidered as  a  kind  of  Gordian  knot  in  anatomy. 
Vesalius,  Albinus,  and  Haller  J  confessed  their 
inability  to  trace  them,  and  more  lately  De 
Blainville§  assures  us,  from  his  own  experi- 
ence, that  we  can  only  arrive  at  very  general 
conclusions  ( des  chases  trts-gtnerales)  on  this 
subject.  By  adopting  the  method  of  long- 
continued  boiling  of  the  organ  before  com- 
mencing to  attempt  to  trace  the  course  and  ar- 
rangement of  its  fibres,  we  will  find  that  after  a 
few  trials  several  of  the  most  important  points 
connected  with  the  distribution  of  these  can  be 
ascertained,  and  by  perseverance  they  can  be 
unravelled  to  a  great  extent.  By  long  boiling 
the  muscular  fibres  are  rendered  hard  and  firm, 
while  the  tendinous  and  cellular  tissues  are 
softened  or  dissolved,  and  the  fat  melted.  Dr. 
Duncan,  who  employed  this  method  to  a  great 
extent,  states  that  the  essential  circumstance  is 
to  continue  the  boiling  long  enough,  and  that 
he  has  never  been  able  to  carry  it  too  far.  I 
have  found  from  eighteen  to  twenty  hours  gene- 
rally sufficient  for  this  purpose.  Some  have 
recommended  that  the  heart  should  be  pre- 
viously put  for  a  short  time  into  a  strong  solu- 
tion of  salt,  and  Vaust  advises  that  it  should 
be  boiled  in  a  solution  of  nitre,  for  the  purpose 
of  rendering  the  fibres  firmer.  The  boiling  is 
infinitely  superior  to  the  maceration  in  vinegar. 
By  stopping  the  boiling  before  the  tendinous 
rings  are  rendered  too  soft,  we  can  easily  see 
their  form  and  their  connexions  to  the  muscular 
fibres. 

The  eeneral  connexion  and  distribution  of 

*  [This  however  is  denied  by  other  observers, 
and  from  very  recent  and  careful  examinations. 
See  the  succeeding  article  by  Mr.  Searle. — Ed.] 

t  Memoires  de  l'Academie  Royale  des  Sciences, 
1711,  p.  197. 

X  El.  Phys.  torn.  i.  p.  351. 

§  Cours  de  Physiologie,  &c.  torn.  ii.  p.  359. 


HEART. 


591 


the  muscular  fibres  of  the  ventricles  may  be 
stated  to  be  as  follows.    1st,  Most  of  these 
fibres  are  connected  by  both  extremities  to  the 
tendinous  structure  of  the  heart,  a  fact  well 
known  to  Lower,*  though  overlooked  by  many 
subsequent  anatomists.    2d,  The  direction  of 
these  fibres  is  more  or  less  oblique,  a  com- 
paratively small   part  of  them   only  being 
vertical,  and    that  too  for  a  limited  part  of 
their  course.      The   degree  of  obliquity  of 
these  spiral  turns  is  different  in  different  por- 
tions of  the  heart :  they  are  more  ob- 
lique on  the  surface  and  less  oblique 
as  we  proceed  to  the  deeper  fibres, 
more  particularly  at  the  base.  The 
deeper  fibres  approach  more  to  the  cir- 
cular form.    3d,  As  has  been  already 
stated,  part  of  these  fibres  are  common 
to  both  ventricles;   while   part  only 
belong  exclusively  to  a  single  ventricle, 
and  that  principally  at  the  base.  4th, 
The  external  fibres  are  longer  than  the 
next  in  order,  and  after  turning  round 
the  apex  pass  upwards  into  the  interior, 
below  the  lower  margin  of  the  shorter 
fibres,  and  form  the  inner  surface  of 
the  ventricles,  while  the  deeper  again 
turn  up  below  the  lower  margin  of  the 
fibres  next  in  succession,  so  that  the 
longer  enclose  by  their  two  extremities 
all  the  shorter  fibres.    By  this  arrange- 
ment we  can  explain  how  the  base  and 
middle  part  of  the  ventricles  should 
be  much  thicker  than  the  apex.  This 
arrangement  has  been  particularly  in- 
sisted upon  by  Dr.  Duncan  and  Gerdy, 
and  to  illustrate  it  Gerdy  has  given  an 
ideal  illustration,  of  which  fig.  271  is  a 
copy. 

Fie.  271. 


run  in  a  spiral  manner  from  above  downwards 
and  from  right  to  left,  while  those  on  the  pos- 
terior surface,  which  are  in  general  more  ver- 
tical, run  from  left  to  right.  Most  of  these 
bands  are  thin  and  broad  at  the  upper  part, 
and  become  narrower  and  thicker  as  they  ap- 
proach the  apex,  where  they  form  a  remarkable 
twisting,  which  has  been  termed  the  vortex, 
(of  which  jig.  272,  taken  from  the  human  heart 
after  boiling,  is  an  accurate  representation,)  and 
then  pass  in  to  assist  in  forming  the  inner  surface 

Fig.  272. 


of  the  left  ventricle  and  the  columnar  carnere. 
The  manner  in  which  the  external  fibres  turn 
in  at  the  apex  to  form  the  inner  surface  of  the 
ventricles  and  enclose  the  deeper  fibres  was 
well  known  to  Lower,  and  he  has  illustrated 
it  by  an  engraving,  of  which  Jig.  273  is  a  copy. 


In  examining  the  course  of  the  fibres  of  the 
ventricles  we  shall  not  attempt  to  describe  each 
particular  band  of  fibres,  but  confine  ourselves 
to  their  general  arrangement.f  In  examining 
the  surface  of  the  ventricles  the  superficial 
fibres  of  the  anterior  surface  are  observed  to 

*  Tractatus  de  Corde,  p.  34  to  37.  Lugd.  Batav. 
1669. 

t  Wolff  has  named  and  minutely  described  eight 
distinct  bands  of  muscular  fibres  on  the  surface  of 
the  right  ventricle  :  Acta  Petropolit.  pro  anno  1781, 
torn.  viii.  p.  251,  1785. 


592 


HEART. 


This  arrangement  of  the  external  fibres  was 
also  well  known  to  Winslow*  and  Lancisi.f 
Winslow,  however,  denied  that  they  described 
the  figure  of  eight,  as  stated  by  Lower.  More 
lately  Gerdy  has  given  a  description  of  this 
arrangement,  to  which  he  has  added  an  en- 
graving, which  approaches  more  to  the  ap- 
pearance of  the  perfect  figure  of  eight  than 
that  given  by  Lower.  I,  however,  prefer  that 
given  by  Lower,  as  it  more  nearly  resembles 
the  arrangement  which  I  have  myself  seen  in 
tracing  these  fibres.  A  small  part  of  the  right 
and  posterior  side  of  this  vortex  is  formed  by 
fibres  from  the  posterior  surface  of  the  left 
ventricle,  and  from  that  part  of  the  posterior 
surface  of  the  right  ventricle  near  the  septum, 
and  are  attached  above  to  the  auricular  tendi- 
nous rings,  while  the  whole  of  the  anterior  and 
left  side  of  the  vortex  is  formed  by  fibres  from 
the  anterior  surface  and  right  margin  of  the 
ventricles.  On  tearing  these  last  fibres,  which 
form  the  principal  part  of  the  apex,  from  the 
anterior  surface  of  the  left  ventricle,  we  find, 
as  we  proceed  upwards,  that  a  comparatively 
small  part  of  them  cross  the  anterior  fissure 
upon  the  right  ventricle  to  reach  the  right  au- 
ricular tendinous  ring.  The  greater  number 
dip  in  at  the  anterior  longitudinal  fissure,  and 
we  shall  afterwards  find  that  they  can  be  traced 
to  the  base  of  the  septum  of  the  ventricles. 
By  tearing  off'  these  fibres  downwards,  we  open 
into  the  apex  of  the  left  ventricle.  A  general 
notion  of  the  manner  in  which  these  fibres, 
passing  from  the  base  of  the  septum,  turn  in 
at  the  apex,  and  proceed  upwards  on  the  inner 
surface  of  the  left  ventricle,  may  be  obtained 
from  fig.  273.  To  have  been  quite  accurate 
the  inner  fibres  should  have  been  more  scat- 
tered, and  some  of  them  represented  as  termin- 
ating in  the  columnse  carneoe.  By  unravelling 
the  fibres  which  form  the  apex,  we  may  open 
into  the  interior  of  the  left  ventricle  without 
breaking  a  single  muscular  fibre.  Having  thus 
opened  the  apex  of  the  heart,  although  the 
point  is  removed,  the  circular  edge  is  left  entire 
(fig.  274,  a),  and  is  formed  of  another  series 


Fig.  274. 
I 


*  Memoires  de  l'Acad.  Roy.  1711.  p.  197. 
t  De  Motu  Cordis  :  Opera  omnia,  torn.  iv.  p.  96. 
1745. 


of  fibres,  which,  like  those  taken  away,  ad- 
vance spirally  from  the  base  to  the  apex,  and 
turning  over  the  edge  (fig.  274,  b)  ascend  in 
the  opposite  direction,  continuing  their  course 
after  being  reflected.  "  Proceeding  in  the 
same  manner  the  whole  apex  of  the  left  ven- 
tricle may  be  removed,  and  the  same  principle 
of  arrangement  is  found  throughout  the  whole 
heart  even  to  the  base.  When  we  get  down  as 
far  as  the  apex  of  the  right  ventricle,  although 
the  principle  remains  the  same,  its  effects  are 
more  complicated,  as  it  applies  to  two  cavities 
instead  of  one."  I  have  frequently  satisfied 
myself  of  the  correctness  of  the  description 
contained  in  this  passage,  which  I  have  quoted 
from  the  manuscript  of  Dr.  Duncan.  This  is 
the  same  kind  of  arrangement  which,  we  have 
already  stated,  has  been  insisted  upon  by 
Gerdy,  but  which  we  believe  can  be  more 
satisfactorily  seen  by  tracing  the  fibres  in  this 
manner.  Gerdy  lays  it  down  as  a  general  law, 
that  all  the  fibres  of  the  heart  form  loops,  the 
apices  of  which  look  towards  the  apex  of  the 
heart  (fig.  271).  I  find  that  Dr.  Duncan 
states  that  while  the  apices  of  those  loops 
which  form  the  lower  part  of  the  heart  point 
to  the  apex,  as  Gerdy  has  described,  "  yet  he 
commits  a  great  error  when  he  asserts  that  the 
apices  of  all  the  fibres  of  the  heart  point  in 
that  direction,  since  the  number  of  tops  which 
point  in  the  opposte  direction  is  not  less."* 
When  the  superficial  fibres  of  the  heart  have 
been  removed  as  represented  in  fig.  274,  we 
will  find  that  if  we  trace  the  great  mass  of 
fibres  occupying  the  lower  and  middle  part  of 
the  left  ventricle,  they  will  be  seen  to  run 
spirally  in  strong  bundles  from  above  down- 
wards and  from  right  to  left,  to  wind  round 
and  form  the  posterior  as  well  as  the  anterior 
part  of  the  point  of  the  heart;  that  the  greater 
mass  pass  in  at  the  apex  of  the  left  ventricle  to 
assist  in  forming  the  columnae  carneae  and  in- 
ternal surface,  while  others  pass  in  at  the  apex 
of  the  right  ventricle,  and  others  again,  after 
turning  a  little  upwards,  dip  into  the  interior 
below  some  of  the  higher  fibres.  On  tracing 
them  upwards,  on  the  other  hand,  they  dip  in 
at  the  anterior  longitudinal  fissure  (fig.  274,  d) 
where  they  are  as  it  were  dovetailed  with  other 
fibres  from  the  anterior  surface  of  the  right 
ventricle  passing  in  at  the  same  fissure,  and 
then  mount  almost  vertically  upwards  to  the 
base  of  the  septum,  forming  part  of  the  sep- 
tum of  the  right  ventricle,  only  separated  from 
its  lining  membrane  by  a  thin  layer  of  fibres, 
and  are  inserted  in  a  strong  band  in  the  ox 
into  the  bone  of  the  heart,  which  is  placed 
between  the  auriculo-ventricular  openings  and 
aorta,  while  in  the  human  heart  they  are  spread 

*  I  could  not  discover  in  Dr.  Duncan's  manu- 
script any  other  description  or  allusion  to  the  fibres 
here  mentioned  whose  arrangement  is  opposed  to 
the  general  law  which  Gerdy  is  anxious  to  establish. 
There  is  no  doubt,  however,  that  many  of  these 
loops  at  the  base  are  principally  directed  to  the 
periphery  of  the  organ,  and  very  little  downwards, 
and  that  a  few  in  the  infundibulum  are  slightly 
directed  upwards. 


HEART. 


593 


over  a  wider  surface  at  this  their  upper  in- 
sertion. I  have  been  more  particular  in 
describing  this  part  of  the  heart,  as  this  ar- 
rangement of  the  fibres  appears  to  me  to  be 
intimately  connected  with  the  production  of 
the  tilting  motion  of  the  heart.  The  fibres 
which  occupy  the  upper  part  of  the  anterior 
surface  of  the  left  ventricle,  as  well  as  those 
occupying  the  upper  part  of  the  posterior 
surface  (nearer  the  base  than  those  bands 
already  described  as  passing  from  the  ante- 
rior surface),  partly  dip  into  the  interior  of 
the  left  ventricle  as  they  wind  round  it, 
partly  pass  in  at  the  posterior  longitudinal 
groove  to  assist  in  forming  the  septum,  while 
other  strong  bands,  more  particularly  near  the 
base,  cross  this  groove  and  dip  into  the  interior 
of  the  right  ventricle.  In  the  human  heart 
I  have  stripped  off  pretty  strong  superficial 
bundles  from  the  upper  part  of  the  posterior 
surface  of  the  left  ventricle  over  the  posterior 
longitudinal  groove,  and  over  the  surface  of 
the  right  ventricle  as  far  as  the  anterior  longitu- 
dinal fissure,  into  which  they  dipped.  In 
stripping  off  the  fibres  from  the  posterior  and 
anterior  surface  of  the  right  ventricle  at  this 
stage  of  the  dissection,  part  of  them  disap- 
pear in  their  course  around  the  ventricle,  where 
they  dip  in  to  assist  in  forming  the  interior; 
others  proceed  as  far  as  the  anterior  groove 
before  they  dip  inwards;  while  part  of  the 
fibres  which  arise  from  the  conus  arteriosus 
cross  the  upper  part  of  the  anterior  fissure 
upon  the  anterior  surface  of  the  left  ventricle, 
where  they  pass  into  the  interior  of  the  left 
ventricle.  These  fibres,  crossing  the  anterior 
surface  of  the  right  ventricle,  and  which  dip 
in  at  the  anterior  fissure,  form  the  inner  sur- 
face of  the  septum  of  the  right  ventricle.  On 
tracing  those  fibres  which  dip  inwards  at  so 
many  different  points,  they  are  observed  to  rise 
upwards  to  the  tendinous  rings  either  directly 
or  indirectly  through  the  medium  of  the  chorda 
tendinese.  In  following  the  fibres  in  this  man- 
ner we  perceive  the  intimate  connexion  that 
exists  between  the  two  ventricles,  and  that  their 
contraction  must  be  simultaneous.  We  also 
see  that  comparatively  few  fibres  cross  the 
anterior  longitudinal  groove  except  near  the 
base,  while  large  bundles  of  fibres  cross  the 
posterior  groove.  When  these  fibres  crossing 
the  two  grooves  have  been  torn  away,  the  two 
ventricles  become  detached  from  each  other. 
By  this  time  the  apices  of  both  ventricles  have 
been  opened. 

On  examining  the  deeper  fibres  (which  oc- 
cupy that  part  of  the  heart  near  the  base),  they 
are  seen  to  form  a  series  of  curved  bands,  of 
one  of  which  fig.  275  is  a  representation. 
These  bands  are  imbricated,  the  lower  disap- 
pearing by  its  internal  extremity  below  the 
higher,  so  as  to  be  inserted  by  that  extremity 
into  the  tendinous  rings  at  a  point  more  in- 
ternal than  the  corresponding  extremity  of  the 
higher  bands.  Some  of  these  bands  are  com- 
mon to  both  ventricles,  others  belong  exclu- 
sively to  one.  The  fibres  of  the  right  ventricle 
become  very  complicated  where  they  form  the 
eonus  arteriosus  and  fleshy  pons  between  the 

VOL.  II. 


Fig.  275. 


pulmonary  artery  and  right  auriculo-ventricular 
orifice.  The  fibres  of  the  left  ventricle  are 
stronger  and  coarser  than  those  of  the  right 
ventricle,  while  those  of  the  conus  arteriosus 
are  still  firmer  than  those  on  the  lower  part  of 
the  right  ventricle.*  "  There  do  not  occur  in 
any  part  of  the  heart  cellular  sheaths  or  ten- 
dinous aponeuroses  dividing  bundles  of  fibres 
as  separate  muscular  fasciculi.  Although  a 
complex  it  is  not  a  compound  muscle,  and 
does  not  consist  of  a  number  of  distinct  bellies 
or  heads.  The  only  thing  approaching  to  this 
structure  are  the  column-ae  and  a  strong  mus- 
cular stay  between  the  peripheral  and  septal 
wall  of  the  pulmonic  ventricle,  and  the  re- 
ticulated texture  on  the  inside  of  the  ventricles, 
much  more  conspicuous  in  man  than  in  oxen." 
"  Many  fibres  are  attached  to  each  other  by 
agglutination  or  in  a  manner  not  easily  under- 
stood." "  Many  fibres  bifurcate,  and  the  di- 
vided fibres  follow  different  directions  :  or  two 
fibres  from  different  parts  approximate,  and  at 
last  are  united  and  proceed  as  one  fibre.  I  am 
doubtful  if  this  can  be  considered  as  a  tendinous 
point  of  union  of  all  three.  These  points  of 
union  are  often  arranged  in  one  line  so  as  to 
give  some  appearance  of  a  pennated  muscle, 
but  the  tendinous  points,  if  they  exist,  do  not 
adhere  to  form  membranes  or  strings.  This 
bifurcation  is  very  evident  in  the  connection 
of  the  septal  with  the  peripheral  walls  of  the 
heart. "f 

The  auricles  are  formed  by  two  sets  of  fibres, 
a  superficial  and  a  deep.  The  arrangement  of 
these  two  sets  of  fibres  does  not  follow  the 
same  laws  as  those  of  the  ventricles.  The  su- 
perficial layer  (fig.  276,  a  a,  fig.  277,  a  a), 
surrounds  the  base  of  the  auricles,  and  is  of 
unequal  height  and  thickness.  It  is  broader 
on  the  anterior  and  narrow  on  the  posterior 
surface,  more  particularly  on  the  posterior  and 
outer  part  of  the  right.  It  extends  upwards 
towards  their  superior  edge  on  the  anterior 
surface,  and  on  the  posterior  surface  of  the 
left  as  far  as  the  inferior  pulmonary  veins. 
It  is  very  thin,  particularly  on  the  outer 
and  posterior  part  of  the  right  auricle.  In  its 
course  round  the  auricles  the  fibres  diverge  to 
enclose  the  appendices,  and  the  orifices  of  the 

*  Dr.  Duncan  has  given  a  very  minute  descrip- 
tion of  the  fibres  of  this  and  other  parts  of  the 
heart,  which  are  ranch  too  long  for  insertion  here. 
He  lias  also  given  a  very  accurate  and  minute  de- 
scription of  the  bone  in  the  heart  of  the  ox. 

t  Dr.  Duncan. 

2  n. 


594 


HEART. 


Fig.  276. 


large  veins.  These  fibres  cross  transversely 
between  the  anterior  surface  of  the  two  auricles 
and  connect  them  together.  These  superficial 
fibres  are  also  prolonged  into  the  interauricular 
septum  (Jig.  277,  f)  to  assist  in  forming  the 


Fig.  277. 


circular  band  of  fibres  which  surrounds  the 
fossa  ovalis.  Gerdy  figures  a  superficial  band 
of  fibres  (Jig.  276,  b)  as  belonging  exclusively 
to  the  left  auricle. 

The  deep  fibres  belong  exclusively  to  a  sin- 
gle auricle.  They  are  superficial  at  various 
parts,  where  the  external  or  circular  fibres  are 
deficient.  By  their  inner  surface  they  are  con- 
nected to  the  inner  membrane  of  the  auricles,and 
a  thin  layer  of  cellular  tissue  unites  their  outer 
surface  to  the  inner  surface  of  the  superficial 
fibres.  In  the  left  auricle  Gerdy  describes, 
1st,  a  left  auricular  loop  (Jig.  276,  c  c,  Jig.  277, 
c  c),  which  embraces  the  auricle  from  its  su- 
perior edge  to  its  base,  which  runs  a  little 
obliquely  to  the  left,  before,  above,  and  then 
behind  the  auricle,  and  is  attached  by  its  ex- 
tremities to  the  auricular  tendinous  ring  near 
the  septum.  It  is  contracted  at  that  part  where 
it  passes  between  the  pulmonary  veins.  2d. 
The  pulmonary  veins  are  surrounded  by  circu- 
lar fibres  (fig.  276,  d  d,  fig.  277,  d  d),  which 
are  continued  along  their  course  to  a  variable 
extent,- — sometimes  they  merely  surround  the 
termination  of  one  or  more  of  these  veins, 
at  other  times  I  have  seen  them  prolonged  out- 
wards as  far  as  the  roots  of  the  lungs.  These 
fibres  generally  form  a  continuous  layer,  and 


of  sufficient  thickness  to  render  them  capable 
of  constricting  these  vessels  considerably.  3d. 
Some  fibres  proper  to  the  appendix  (fig.  276, 
m  m),  which,  by  passing  between  and  uniting 
themselves  to  the  other  fibres  of  the  appendix, 
form  that  reticulated  appearance  which  it  pre- 
sents in  its  inner  surface.  Some  of  these  fibres 
are  circular,  others  form  incomplete  circles. 

In  the  right  auricle,  Gerdy  has  described, 
1st,  a  right  auricular  loop  (fig.  276,  h  h,  fig. 
277,  h),  which  is  attached  anteriorly  to  the 
tendinous  structure  at  the  base  of  the  auricle; 
it  extends  upwards  in  the  anterior  edge  of  the 
septum  auiiculorum  ;  it  then  curves  round  the 
fossa  ovalis,  of  which  it  forms  the  projecting 
edge,  and  at  the  orifice  of  the  vena  cava  supe- 
rior it  divides  into  a  right  and  left  band.  The 
first  proceeds  downwards,  becomes  engaged 
with  some  of  the  superficial  fibres  around  the 
cava  superior,  and  forms  the  angle  between 
them  (tuberculum  Loweri),  from  which  it 
passes  downward  to  the  auricular  tendinous 
ring  along  the  right  side  of  the  cava  inferior. 
The  left  division  passes  along  the  left  side  of 
the  cava  inferior,  in  the  posterior  edge  of  the 
auricular  septum,  where  it  intermixes  with  the 
fibres  which  embrace  the  entrance  of  the  coro- 
nary vein.  2d,  Some  muscular  fibres  (fig. 
276,  p),  which  pass  between  the  anterior  part 
of  the  tendinous  ring  and  the  appendix.  3d, 
Some  circular  fibres,  which  surround  the  en- 
trance of  the  cava  superior  (fig.  276,  o)  :  these 
do  not  extend  upwards  beyond  the  orifice  of 
the  vein.  4th,  The  bundles  of  fibres  which 
arise  from  the  right  side  of  the  auricular  ring 
proceed  upwards  to  the  posterior  part  of  the 
appendix,  and  form  the  musculi  pectinati 
seen  in  the  interior  of  the  auricle.  5th,  A  few 
fibres  proper  to  the  auricle  (fig.  276,  w),  which 
assume  the  circular  form.  The  action  of  all 
these  fibres  superficial  as  well  as  deep  must  be 
to  diminish  the  capacity  of  their  cavities,  and 
draw  them  towards  the  auriculo-ventricular 
openings,  and  thus  favour  the  passage  of  their 
contents  through  these  openings. 

Inner  membrane  of  the  heart. — Each  side  of 
the  heart  has  its  own  lining  membrane,  and 
botli  of  these  are  closely  allied  to  the  serous 
membranes  in  structure  and  appearance.  They 
are  continuous  with  the  inner  coat  of  the  vessels 
which  open  into  their  different  cavities.  These 
have  been  termed  the  endocarde  by  Bouillaud 
to  distinguish  them  from  the  serous  coat  of  the 
pericardium  on  the  outer  surface  of  the  heart. 
If  we  commence  to  trace  the  inner  membrane 
of  the  right  side  from  the  entrance  of  the  two 
cava?,  we  find  that  it  is  folded  upon  itself  to 
form  the  Eustachian  valve  at  the  entrance  of 
the  inferior  cava ;  it  then  passes  upon  the  inner 
surface  of  the  auricle,  and  at  the  opening  of  the 
coronary  vein  it  is  again  folded  upon  itself  to 
form  the  valve  of  the  coronary  vein.  It  passes 
through  the  auriculo-ventricular  opening,  ad- 
heres to  the  inner  surface  of  the  tendinous  ring, 
and  is  there  folded  upon  itself  to  assist  in  form- 
ing the  tricuspid  valve.  It  now  proceeds  upon 
the  inner  surface  of  the  ventricle,  and  at  the 
origin  of  the  pulmonary  artery  it  assists  in 
forming  the  semilunar  valves,  and  becomes  con- 


HEART. 


595 


tinuous  with  its  inner  coat.  If  we  trace  they 
inner  membrane  of  the  left  side  of  the  heart 
from  the  entrance  of  the  pulmonary  veins,  we 
find  that,  after  lining  the  auricle,  it  is  continued 
through  the  auriculo-ventricular  opening,  and 
is  there  folded  upon  itself  to  assist  in  forming 
the  mitral  valve.  In  the  left  ventricle  it  sur- 
rounds the  chordae  tendineae  and  unattached 
columnar  carnese  in  the  same  manner  as  in  the 
right  ventricle  ;  and  at  the  origin  of  the  aorta  it 
assists  in  forming  the  semilunar  valve,  and  be- 
comes continuous  with  the  inner  coat  of  the 
artery.  These  membranes  adhere  intimately  to 
the  inner  surface  of  the  heart  by  close  cellular 
tissue,  and  have  their  inner  surface  perfectly 
polished  and  smooth.  That  of  the  left  auricle 
is  thicker  than  that  of  the  right.  They  are 
thicker  in  the  auricles  than  in  the  ventricles. 
In  the  ventricles,  except  near  the  origin  of  the 
large  arteries,  they  are  exceedingly  thin. 

Nerves  of  the  heart. — The  heart  is  supplied 
with  nerves  from  the  sympathetic  and  par 
vagum.  The  sympathetic  branches  come  from 
the  superior,  middle,  and  inferior  cervical  gan- 
glia, and  frequently  also  from  the  first  dorsal 
ganglion.  The  branches  from  the  par  vagum 
come  directly  from  the  trunk  of  the  nerve,  and 
indirectly  from  the  recurrent  or  inferior  laryn- 
geal. The  course  of  these  on  the  right  side 
differs  from  those  of  the  left  in  some  respects, 
and  requires  a  separate  description.  These 
nerves,  like  most  of  the  other  branches  of  the 
sympathetic,  are  very  irregular  in  their  size, 
number,  and  origin,  so  that  it  would  be  difficult 
to  find  two  subjects  in  which  they  are  exactly 
alike ;  they  are  also  very  irregular  in  their 
course  before  they  reach  the  cardiac  plexus, 
but  become  more  regular  when  they  gain  the 
arteries  of  the  heart,  whose  branches  they  ac- 
company. These  nerves,  after  forming  diffe- 
rent anastomoses  and  plexuses  with  each  other 
of  the  same  side,  converge  at  the  upper  and 
back  part  of  the  arch  of  the  aorta,  where  they 
form  a  free  anastomosis  with  those  of  the  oppo- 
site side,  and  then  pass  on  to  the  heart.  The  left 
cardiac  nerves  are  sometimes  much  smaller 
than  those  on  the  right  side,  so  as  to  appear,  as 
in  the  dissection  described  by  Lobstein,*  merely 
accessory  to  those  on  the  right.  On  the  other 
hand  the  size  of  those  on  the  left  side  may  pre- 
ponderate considerably  over  those  on  the  right. 
The  proportional  size  of  the  different  nerves  of 
the  same  side  is  also  very  various.  When  the 
nerves  of  one  side  are  small,  the  deficiency  is 
made  up  by  the  greater  size  of  those  of  the  op- 
posite side  ;  and  when  any  particular  branch  is 
either  unusually  small  or  entirely  wanting,  its 
place  is  supplied  by  the  greater  size  of  the 
other  nerves  of  the  same  side,  or  of  those  of  the 
opposite  side.  The  branches  from  the  par 
vagum,  particularly  those  coming  from  the  re- 
current, vary  also  considerably  in  size.  All 
the  sympathetic  branches  of  the  cardiac  plex- 
uses are  of  a  gray  colour,  and  are  generally  not 
so  soft  as  Scarpa  has  described  them. 

The  right  cardiac  branches  of  the  sympathe- 

*  De  Nervi  Sympathetici  humani  fabrica,  &c. 
pp.  16  &  18. 


tic  are  generally  three  in  number:  1st,  superior 
cardiac  ( supremus  et  superficialis  cordis)  arises 
from  the  lower  and  inner  part  of  the  superior 
cervical  ganglion,  or  from  the  continuation  of 
the  sympathetic  between  the  superior  and 
middle  ganglia,  or  from  both  these  origins.  It 
generally  also  receives  a  filament  from  the  par 
vagum.  In  its  course  down  the  neck  it  lies 
behind  the  sheath  of  the  carotid  artery.  It 
anastomoses  with  the  external  laryngeal  nerve 
and  descendens  noni,  and  sends  a  twig  along 
the  inferior  thyroid  artery  to  the  thyroid  body  ; 
and  at  the  lower  part  of  the  neck  it  sometimes 
divides  into  two  branches  as  figured  by  Scarpa,* 
one  of  which  unites  itself  to  the  middle  car- 
diac, the  other  forms  an  anastomosis  with  the 
recurrent  nerve  of  the  same  side.  At  other 
times  it  passes  into  the  thorax  either  in  front  or 
behind  the  subclavian  artery,  takes  the  course 
of  the  arteria  innominata,  and  reaches  the  pos- 
terior part  of  the  arch  of  the  aorta,  where  it 
anastomoses  with  branches  of  the  middle  and 
inferior  cardiac  nerves,  or  with  branches  of  the 
recurrent.  It  more  rarely  appears  to  pass  to 
the  cardiac  plexus  without  any  anastomosis 
with  the  middle  and  inferior  cardiac  branches. 
It  frequently  presents  a  ganglion  in  its  course 
down  the  neck. 

Middle  cardiac  nerve. — This  nerve  arises  by 
several  short  twigs  from  the  middle  cervical 
ganglion.  This  is  generally  the  largest  of  the 
cardiac  nerves,  and  is  named  by  Scarpa  the 
great  or  deep  cardiac  nerve  ( n.  cardiacus  me- 
dius,  s.  profundus,  s.  magnus).  It  proceeds 
downwards  and  inwards,  crosses  the  subclavian 
artery,  sometimes  in  front,  at  other  times  it  di- 
vides into  several  branches,  which  surround  the 
artery  and  again  unite.  It  anastomoses  with 
the  branches  of  the  recurrent,  in  the  neigh- 
bourhood of  which  it  runs,  also  with  the  par 
vagum,  superior  and  inferior  cardiac  nerves ; 
and  following  the  course  of  the  arteria  innomi- 
nata it  passes  behind  the  arch  of  the  aorta  to 
terminate  in  the  cardiac  plexus. 

Inferior  cardiac  nerve  (n.  cardiacns  minor 
of  Scarpa). — This  nerve  generally  arises  by  fila- 
ments from  the  inferior  cervical  ganglion,  some- 
times from  the  first  dorsal  ganglion,  at  other 
times  from  both.  It  proceeds  behind  the  sub- 
clavian artery  near  to  the  recurrent  nerve.  It 
follows  the  course  of  the  innominata  close  to 
the  middle  cardiac,  with  which  it  anastomoses, 
and  proceeds  to  join  the  cardiac  plexus. 

Left  cardiac  nerves. — Perhaps  the  differences 
in  the  course  of  the  right  and  left  cardiac  nerves 
are  principally  to  be  attributed  to  the  known 
differences  between  the  large  arteries  of  the  two 
sides.  The  left  superficialis  cordis  is  figured 
by  Scarpaf  as  dividing  a  little  above  the  arch 
of  the  aorta  into  four  branches ;  two  of  these 
pass  in  front  of  the  aorta  to  form  an  anastomo- 
sis with  a  branch  of  the  par  vagum  and  deep 
cardiac  ;  a  third  also  passes  in  front  of  the  aorta, 
to  unite  itself  with  the  middle  cardiac;  and  the 
remainder  of  the  nerve  proceeds  behind  the 
arch  to  unite  itself  with  the  cardiac  plexus. 

*  Tab.  iii.  Tabulae  Neurologies,  &c. 
i  Tab.  iv.  op.  cit. 

2  u  2 


596 


HEART. 


The  left  middle  cardiac  nerve  is  generally 
smaller  than  the  right,  and  is  frequently  partly 
formed  by  a  branch  from  the  inferior  cervical 
ganglion.  It  passes  behind  the  arch  of  the 
aorta,  sometimes  in  the  form  of  a  single  trunk, 
sometimes  double,  at  other  times  triple,  and 
generally  throws  itself  into  the  upper  and  left 
part  of  the  cardiac  plexus. 

Cardiac  plexus  (great  cardiac  plexus  of 
Haller)  is  placed  behind  the  arch  of  the  aorta 
and  in  front  of  the  lower  part  of  the  trachea, 
extending  from  the  arteria  innominata  to  the 
right  branch  of  the  pulmonary  artery,  and  is 
formed  by  the  convergence  of  nearly  the  whole 
of  the  cardiac  nerves  of  both  sides,  but  more 
particularly  of  the  middle  cardiac  nerves. 
There  is  occasionally  a  distinct  ganglion  at  the 
junction  of  these  nerves;  more  generally  there 
is  only  a  plexiform  arrangement.  From  this 
plexus  a  very  few  branches  pass  upon  the  ante- 
rior surface  of  the  aorta  (  cardiuci  superficiales 
aorta ),  and  anastomose  with  the  right  coronary 
plexus  :  some  twigs  also  pass  backwards  to 
anastomose  with  the  bronchial  plexuses.  By 
far  the  greater  part  of  the  cardiac  plexus  pro- 
ceeds to  the  heart  in  the  form  of  two  large 
divisions  to  form  the  right  and  left  coronary 
plexuses  which  accompany  the  coronary  arte- 
ries. Where  the  right  branch  leaves  the  lower 
part  of  the  plexus  there  is  a  gangliform  swelling 
(ganglion  of  Wrisberg),  which  is  occasionally, 
however,  very  indistinct.  This  ganglion  fur- 
nishes the  greater  part  of  the  superficial  plexus 
of  the  aorta  which  we  have  just  described.  This 
great  right  cardiac  branch  divides  into  two 
parts;  the  smaller  passes  between  the  aorta  and 
pulmonary  artery  to  reach  the  right  side  of  the 
origin  of  the  pulmonary  artery,  where  it  attaches 
itself  to  the  right  coronary  artery  to  form  the 
principal  part  of  the  right  coronary  plexus  ;  the 
other  and  larger  portion  creeps  under  the  pul- 
monary artery  to  the  posterior  part  of  the  heart, 
to  assist  in  forming  the  left  coronary  plexus. 
The  great  left  cardiac  branch,  which  principally 
comes  from  the  upper  part  of  the  cardiac  plexus, 
and  at  first  passes  from  right  to  left  posterior  to 
the  ductus  arteriosus,  after  which  it  is  joined 
by  other  smaller  branches  which  pass  in  front 
of  the  ductus  arteriosus.  It  also  divides  into 
two  branches  ;  the  smaller  passes  between  the 
aorta  and  pulmonary  artery,  and  reaches  the 
origin  of  the  right  coronary  artery,  and  throws 
itself  into  the  right  coronary  plexus  ;  the  larger 
bends  round  the  posterior  surface  of  the  pulmo- 
nary artery  to  reach  the  left  coronary  artery, 
where  it  forms,  with  the  larger  branch  of  the 
right,  the  left  coronary  plexus.  There  is  thus 
a  free  interchange  of  filaments  between  the 
nerves  of  both  sides.  The  left  coronary  plexus 
is  considerably  larger  than  the  right,  in  propor- 
tion as  the  left  side  of  the  heart  is  thicker  than 
the  right.  These  coronary  plexuses  consist  of 
a  number  of  minute  filaments  which  accom- 
pany the  ramifications  of  the  coronary  arteries 
everywhere,  and  are  distributed  upon  the  sur- 
face of  the  auricles  as  well  as  upon  the  ventri- 
cles. They  anastomose  with  each  other  upon 
the  anterior  and  posterior  surface  of  the  heart. 
All  the  nerves  of  the  heart  enter  into  its  sub- 


stance upon  the  surface  of  the  arteries,  and 
cannot  be  traced  beyond  the  second  or  third 
division  of  the  arteries.  The  nerves  of  the 
heart  are  generally  considered  to  be  small  com- 
pared to  the  size  of  the  organ.*  Though  the 
nerves  of  the  heart  are  not  equal  in  size  to 
those  of  the  tongue  and  eye,  yet  Scarpa  is 
doubtful  if  they  are  not  equal  to  the  nerves  of 
the  other  voluntary  muscles,  as,  for  example, 
the  muscles  of  the  arm.  It  must  be  remem- 
bered that  the  minute  subdivision  and  diffusion 
of  these  nerves  over  a  large  extent  of  surface, 
by  which  many  of  them  can  only  be  seen  after 
a  minute  examination,  causes  them  to  appear  of 
less  size  than  what  they  collectively  really  are. 
Soemmerring  maintained  that  very  few  of  the 
nerves  of  the  heart  were  distributed  to  the  mus- 
cular tissue  of  the  heart,  and  that  they  more 
properly  belonged  to  the  arteries  :  "  nervi  car- 
diaci  proprie  ad  arterias,  ad  aortam  et  arterias 
coronarias  pertinent,  eaque  filia  subtilia  nervo- 
rum parum  sibi  (cordi)  constant." \  Behrends, 
the  pupil  of  Soemmering,  affirmed  that  not  a 
single  twig  went  to  the  muscular  tissue  of  the 
heart,  but  that  they  were  entirely  distributed  on 
the  coats  of  the  arteries. J  The  announcement 
of  these  opinions,  bearing  so  directly  as  they  do 
upon  the  Hallerian  doctrine  of  the  nature  of 
irritability,  so  keenly  agitated  immediately  be- 
fore throughout  Europe,  could  not  fail  to  create 
considerable  sensation  at  the  time,  and  it  is 
probable  that  to  this  we  owe  the  splendid  work 
of  Scarpa  upon  the  nerves  of  the  heart,  which 
has  entirely  set  the  question  concerning  the  dis- 
tribution of  these  nerves  at  rest.  Scarpa  has 
shown  that  when  followed  to  their  minute  dis- 
tribution, the  nerves  of  the  other  muscles  ac- 
company the  arteries  in  the  same  manner  as 
the  nerves  of  the  heart,  and  that  the  nerves  of 
the  heart  only  differ  from  those  of  voluntary 
motion  in  this,  that  the  nerves  accompanying 
the  arteries  of  the  voluntary  muscles  are  firmer 
and  thicker  than  those  of  the  heart. 

Bloodvessels  of  the  heart. — The  heart  is  sup- 
plied with  blood  by  the  two  coronary  arteries, 
for  a  description  of  which  see  Aorta.  The 
blood  is  returned  by  the  coronary  veins.  The 
branches  of  the  coronary  veins  generally  accom- 
pany those  of  the  arteries.  They  are  divided 
into  the  larger  coronary  vein  and  smaller  coro- 
nary veins. 

Great  coronary  vein  (vena  coronaria  maxima 
cordis).  —  This  vein  is  formed  by  several 
branches,  three  of  which  surpass  the  others 
considerably  in  size.  One  of  these  lies  in  the 
anterior  longitudinal  groove  ;  another  runs  along 
the  obtuse  or  left  margin  of  the  heart ;  and  the 
third,  which  may  be  replaced  by  two  or  three 

*  Bichat  in  his  Anatomie  Gencrale  says,  "  that 
the  nervous  mass  intended  for  the  muscles  of  orga- 
nic life  is  much  inferior  to  that  of  the  voluntary 
muscles.  The  heart  and  deltoid  muscle,  on  being 
compared  together,  display  in  this  respect  a  very 
considerable  difference." 

t  Corporis  humani  labrica,  torn.  v. 

\  Dissertatio  qua  demonstratur  cor  nervis  carere. 
After  making  this  general  statement,  he  admits,  in 
one  part  of  his  treatise,  that  he  has  (raced  two 
twigs  of  the  cardiac  nerves  into  the  substance  of  the 
heart. 


HEART. 


597 


smaller  veins,  runs  along  the  posterior  surface 
of  the  left  ventricle,  between  the  obtuse  margin 
and  posterior  longitudinal  groove.  The  first 
of  these  is  frequently  described  as  the  trunk  of 
the  vein,  and  it  commences  at  the  apex  of  the 
heart,  where  it  anastomoses  with  the  smaller 
posterior  and  anterior  veins.  It  runs  upwards 
in  the  anterior  longitudinal  groove  along  with 
the  left  coronary  artery,  gradually  increasing  in 
size  as  it  ascends,  from  the  junction  of  the  other 
veins.  When  it  reaches  the  base  of  the  ventri- 
cles it  changes  its  direction,  enters  the  groove 
between  the  left  auricle  and  ventricle,  leaves 
the  coronary  artery,  passes  from  left  to  right  in 
the  posterior  part  of  the  same  groove,  when  it 
becomes  considerably  dilated  ( sinus  of  the  co- 
ronary vein ).  It  then  opens  into  the  right 
auricle  at  its  lower  and  back  part  close  upon 
the  posterior  edge  of  the  septum  aunculorum. 

Smaller  posterior  coronary  vein  (vena  coro- 
naria  cordis  minor). —  It  commences  at  the 
apex  of  the  heart,  runs  up  in  the  posterior  lon- 
gitudinal groove,  or  a  little  to  its  right  side,  and 
receives  its  blood  principally  from  the  right 
ventricle.  It  generally  joins  the  sinus  of  the 
coronary  vein  ;  at  other  times  it  enters  the  auri- 
cle separately  immediately  by  the  side  of  the 
great  coronary  vein,  so  that  its  aperture  is  also 
covered  by  the  coronary  valve. 

Smaller  anterior  coronary  veins  ( vents  inno- 
minata  of  Vieussens). — These  are  very  small 
and  variable  in  number,  and  are  placed  on  the 
anterior  surface  of  the  right  ventricle.  One  of 
these,  larger  than  the  others,  (generally  the  su- 
perior,) sometimes  receives  the  name  of  ante- 
rior vein  of  Galen.  They  frequently  unite  to 
form  a  single  trunk ;  more  generally  perhaps 
they  continue  separate,  pass  in  front  of  the  right 
coronary  artery  as  it  lies  in  the  auriculo-ventri- 
cular  groove,  and  enter  the  right  auricle  at  its 
anterior  and  inferior  part.  One  of  the  musculi 
pectinati  overlaps  their  entrance,  forming  a  kind 
of  valve. 

Vena  minimis,  or  veins  of  Tltebesius,  Sire 
minute  veins,  which  enter  the  auricle  at  various 
points.  It  was  maintained  by  Vieussens,  The- 
besius,  and  Ruysch,  that  some  of  the  coronary 
veins  opened  into  the  left  side  of  the  heart, 
thus  producing  a  slight  intermixture  of  the  dark 
blood  with  the  arterial.  This  has  been  more 
lately  asserted  by  Abernethy*  and  has  been 
supposed  to  occur  more  frequently  in  phthisical 
cases ;  the  difficulty  of  transmitting  the  blood 
through  the  lungs  causes  their  enlargement. 
Such  injections  are  liable  to  great  fallacy,  from 
the  great  facility  with  which  fine  injections,  or 
even  coarse  injections  when  forcibly  pushed 
into  the  vessels,  escape  into  the  cavities  of 
organs.  Especial  care  is,  therefore,  required  in 
conducting  them.  Notwithstanding  that  we 
have  the  authority  of  some  of  the  most  accurate 
anatomists  in  favour  of  this  opinion,  it  is  very 
doubtful  if  any  of  these  veins  open  into  the  left 
side  of  the  heart.f 

*  Philos.  Trans.  1798. 

t  Professor  Jeffray  (Observations  on  the  Heart, 
&c.  of  the  Foetus,  p.  2)  mentions  a  case  in  which 
the  large  coronary  vein  opened  into  the  left  auricle. 


Sinus  of  the  coronary  vein. — This  is  always 
described  as  a  dilatation  of  the  large  coronary 
vein,  but  I  have  found  it  decidedly  muscular  in 
man  and  in  several  of  the  Mammalia,  as  the 
dog,  horse,  ox,  and  sheep ;  and  it  presents  the 
appearance  of  a  muscular  reservoir  placed  at 
the  termination  of  this  vein,  similar  to  the  auri- 
cles at  the  termination  of  the  two  cava;.  This 
sinus  is  placed  in  the  posterior  part  of  the 
groove  between  the  left  auricle  and  ventricle, 
adheres  intimately  to  the  outer  surface  of  the 
auricle,  and  communicates  by  one  extremity 
with  the  auricle,  and  by  the  other  with  the 
large  coronary  vein.  The  commencement  of 
the  dilatation  is  generally  abrupt,  and  the  first 
appearance  of  the  muscular  fibres  well  defined. 
I  have  seen  it  vary  from  two  inches  to  only 
half  an  inch  in  length.  These  muscular  fibres 
are  generally  circular ;  part  of  them,  however, 
are  oblique.  Some  of  them  belong  exclusively 
to  the  vein  ;  a  great  part  appear  to  be  connected 
with  the  muscular  fibres  of  the  auricle.  This 
muscular  sinus  must  serve  to  prevent  regurgi- 
tation along  the  coronary  veins.  I  have  also 
generally  found  a  distinct  valve  at  the  termina- 
tion of  the  coronary  vein  in  the  sinus.  This 
valve  resembles  the  valves  found  in  the  veins 
of  the  extremities.  It  is  generally  single,  some- 
times it  is  double.  I  have  also  occasionally 
found  one  or  more  single  valves  in  the  course 
of  the  vein.*  A  distinct  valve  may  also  occa- 
sionally be  seen  at  the  termination  of  the  pos- 
terior coronary  vein  in  the  sinus.  Portal  f 
mentions  that  he  has  seen  the  coronary  valve 
situated  in  the  interior  of  the  vein  a  little  from 
its  mouth.  Thebesius  and  Morgagni  have  ob- 
served valves  placed  in  some  of  the  smaller 
veins  where  they  terminate  in  the  larger.  The 
valves  of  the  coronary  veins  do  not  in  general 
prevent  the  passage  of  injections  contrary  to  the 
course  of  the  blood  along  them. 

Lymphatics  of  the  heart. — The  lymphatics 
of  the  heart  are  divided  into  two  sets — super- 
ficial and  deep ;  the  superficial  commencing 
below  the  external  serous  membrane,  and  the 
deep  upon  the  internal  membrane.  They  fol- 
low the  course  of  the  coronary  vessels.  Some 
of  them  pass  directly  into  the  thoracic  duct, 
and,  according  to  Meckel,  sometimes  directly 
into  the  subclavian  or  jugular  veins.  Others 
pass  into  the  lymphatic  glands  situated  in  front 
of  the  arch  of  the  aorta,  while  others  pass  into 
the  glands  situated  around  the  bifurcation  of 
the  trachea,  and  a  few  also  join  the  lymphatic 
vessels  of  the  lungs. 

Pericardium. — The  pericardium  is  a  fibrous 

Lecat  (Mem.  de  l'Acad.  des  Scien.  1738,  p.  62) 
found  the  coronary  veins  in  a  young  child  unite 
themselves  into  a  single  trunk  and  enter  the  left 
subclavian.  It  is  probable  that  Soemmerring  had 
this  case  in  view  when  he  states,  "  Rarissimc  vena 
haec  in  vena  subclavia  dextra  rinitur,"  (de  corp. 
hum.  fab.  torn.  v.  p.  340,  1800  )  particularly  as 
Haller,  (Element.  Phys.  torn.  i.  p.  375,  1757),  in 
quoting  the  case,  has  inadvertently  substituted  the 
word  dextra  for  sinistra. 

*  I  have  seen  two  or  three  pair  of  double  valves 
in  the  course  of  the  coronary  vein  in  the  horse  and 
ass.    These  animals  have  no  Thebesian  valve. 

t  Anatomie  Medicaid,  torn.  iii. 


598 


HEART. 


bag  surrounding  the  heart  and  origin  of  the 
large  bloodvessels,  but  without  any  direct 
attachment  to  the  heart  itself,  having  its  inner 
surface  lined  by  a  serous  membrane.  It  is 
from  this  latter  circumstance  that  it  is  generally 
termed  a  fibro-serous  membrane.  It  is  placed 
behind  the  cartilages  of  the  second,  third,  fourth, 
and  fifth  ribs  of  the  left  side  and  middle  part 
of  the  sternum.  Posteriorly  it  rests  upon  the 
parts  contained  in  the  posterior  mediastinum  ; 
anteriorly  it  corresponds  to  the  anterior  medias- 
tinum, and  may  be  reached  by  perforating  the 
left  side  of  the  sternum,  as  has  been  proposed 
in  some  cases  of  hydrops  pericardii.  The 
pleurae  adhere  to  its  lateral  and  part  of  its 
anterior  surface  by  pretty  close  cellular  tissue, 
when  the  interposed  tat  is  small  in  quantity. 
The  phrenic  nerves  with  their  small  accom- 
panying arteries  pass  down  the  thorax  between 
the  pleurae  and  lateral  surfaces  of  the  pericar- 
dium. Below,  the  fibrous  part  of  the  pericar- 
dium adheres  intimately  to  the  upper  surface 
of  the  cordiform  tendon  of  the  diaphragm,  and 
is  also  connected  by  pretty  dense  cellular  tissue 
to  the  upper  surface  of  the  muscular  fibres 
running  into  the  anterior  part  of  the  left  lobe 
of  the  tendon.  It  adheres  more  firmly  to  the 
cordiform  tendon  at  the  edges,  particularly 
anteriorly,  than  at  the  centre.  It  is  broader 
below  where  it  adheres  to  the  upper  surface  of 
the  diaphragm,  narrower  above  where  it  is 
attached  to  the  large  vessels  that  pass  in  and 
out  from  the  heart.  Upon  these  large  vessels 
the  fibrous  part  of  the  pericardium  is  prolonged, 
forming  a  kind  of  sheath,  which  gradually  be- 
comes thinner  until  it  is  confounded  with  the 
cellular  coat  of  the  vessels.  From  the  manner, 
however,  in  which  the  vena  cava  inferior  enters 
the  heart,  it  can  have  no  fibrous  sheath  of  this 
kind.  At  the  different  points  where  the  fibrous 
coat  becomes  applied  upon  these  vessels,  and 
where  the  cava  inferior  passes  through  the 
cordiform  tendon,  the  serous  coat  is  reflected 
upon  the  outer  surface  of  the  vessels,  and 
accompanies  them  back  to  the  heart  to  cover 
the  outer  surface  of  that  organ.  In  this  man- 
ner the  serous  part  of  the  pericardium  is  a  shut 
sac,  the  outer  surface  of  which  adheres  to  the 
inner  surface  of  the  fibrous  portion,  and  to  the 
outer  surface  of  the  heart.  The  inner  surface, 
like  that  of  all  the  other  serous  membranes,  is 
unadherent,  smooth,  and  shining,  and  is  every- 
where in  contact  with  itself,  and  only  contains 
the  small  quantity  of  fluid  which  serves  to 
lubricate  its  interior.  The  serous  portion  of 
the  pericardium  adheres  intimately  to  the  inner 
surface  of  the  fibrous.  At  that  part,  however, 
where  the  serous  leaves  the  fibrous  to  pass 
back  upon  the  surface  of  the  large  vessels, 
there  is  a  small  triangular  space  left  between 
them.  The  serous  membrane  is  reflected  upon 
and  covers  the  outer  surface  of  the  aorta  rather 
more  than  two  inches  above  its  origin ;  upon 
the  pulmonary  artery  about  the  same  distance 
and  immediately  before  its  bifurcation  ;  upon 
the  cava  superior  about  an  inch  above  its 
entrance  into  the  right  auricle;  upon  the  cava 
inferior  shortly  before  it  reaches  the  heart ;  upon 
the  two  right  pulmonary  veins  soon  after  they 


have  emerged  from  the  right  lung;  and  upon 
the  left  pulmonary  veins  shortly  before  they 
enter  the  auricle.  This  serous  membrane,  in 
passing  upon  the  aorta  and  pulmonary  arteries, 
covers  the  anterior  surfaces  of  both  before  it 
passes  round  upon  their  posterior ;  it  then  en- 
velopes both  arteries  in  the  same  sheath,  so 
that  their  opposed  surfaces  are  only  separated 
from  each  other  by  a  little  cellular  tissue.  It 
leaves  part  of  the  posterior  surface  of  the  cavae 
and  pulmonary  veins  uncovered,  occasionally, 
however,  enveloping  the  whole  or  nearly  the 
whole,  of  the  left  pulmonary  veins.  It  adheres 
but  loosely  to  the  large  bloodvessels,  and  firmly 
to  the  outer  surface  of  the  auricles  and  ven- 
tricles. The  attachment  of  the  fibrous  part  to 
the  cordiform  tendon  is  very  firm  at  the  edges 
and  blended  with  the  tendon,  but  becomes 
looser  towards  the  centre.  Cloquet*  describes 
the  serous  membrane  as  lying  in  contact  with 
the  upper  surface  of  the  cordiform  tendon ;  or, 
in  other  words,  he  appears  to  consider  the 
fibrous  part  not  to  be  prolonged  over  the  upper 
surface  of  the  tendon,  but  to  stop  at  its  attached 
margin.  In  most  cases  I  have  been  able  to 
trace  the  fibrous  part  of  the  pericardium  over 
the  upper  surface  of  the  cordiform  tendon,  but 
almost  always  more  or  less  diminished  in  thick- 
ness. In  some  cases  I  was  unable  to  detect 
anything  like  a  fibrous  layer  at  this  part.  The 
fibrous  part  of  the  pericardium  is  comparatively 
thin,  and  is  composed  of  tendinous  fibres 
interwoven  together.  It  is  not  much  larger 
than  sufficient  to  contain  the  heart  when  its 
cavities  are  distended.  This  fact  taken  along 
with  the  physical  properties  of  the  membrane, 
not  admitting  of  sudden  dilatation,  explains 
how  the  sudden  escape  of  a  small  quantity  of 
blood  (8  oz.  or  sometimes  less)  into  the  interior 
of  the  pericardium  is  sufficient  to  arrest  the 
heart's  action. 

The  arteries  of  the  pericardium  are  small  and 
come  from  various  sources,  from  the  bronchial, 
oesophageal,  phrenic,  from  the  arteries  of  the 
thymus  gland,  internal  mammary,  coronary 
arteries,  and  the  aorta  itself.  Its  veins  partly 
terminate  in  the  azygos,  and  partly  accompany 
the  corresponding  arteries  to  terminate  in  the 
veins  of  the  same  name.  Its  lymphatics  pass 
to  the  glands  placed  around  the  cava  superior. 
The  nerves  can  be  traced  into  its  texture. 

Uses  of  the  pericardium. — The  pericardium 
restrains  within  certain  limits  the  irregular 
movements  of  the  heart.  The  inner  serous 
surface  of  the  pericardium  must  also  facilitate 
its  ordinary  and  healthy  movements. 

Relative  position  of  the  vessels  within  the 
pericardium. — The  pulmonary  artery  at  its  origin 
overlaps  the  anterior  surface  of  the  aorta  as  it 
springs  from  the  left  ventricle.  (See  fig.  276,  s, 
for  the  lelative  position  of  these  vessels  at  their 

*  Traite  d'Anatomie  Descriptive,  p.  633,  trans- 
lated by  Knox.  Cloquet  does  not  state  distinctly 
that  the  fibrous  part  of  the  pericardium  is  not  con- 
tinued over  the  cordiform  tendon,  but  this  may  be 
inferred  from  the  statement  that  the  serous  mem- 
brane "  is  applied  below,  directly  and  in  a  very 
close  manner  upon  the  aponeuroses  of  the  dia- 
phragm." 


HEART. 


599 


origin.)  It  then  proceeds  into  the  concavity  of 
the  arch  of  the  aorta,  and  as  it  is  about  to  pass 
through  the  fibrous  coat  of  the  pericardium,  it 
divides  into  its  two  branches,  the  right  and 
left.  The  left  branch  passes  in  front  of  the 
descending  portion  of  the  arch  of  the  aorta  to 
reach  the  left  lung;  the  right  branch  passes 
behind  the  ascending  portion  of  the  arch  to 
reach  the  right  lung.  In  the  foetus  the  pulmo- 
nary artery  divides  into  three  branches,  the 
two  we  have  just  mentioned,  and  a  third,  the 
ductus  arteriosus,  which  unites  the  pulmonary 
artery  to  the  descending  portion  of  the  arch, — 
in  other  words,  after  the  aorta  has  given  off  the 
large  branches  to  the  head  and  superior  extre- 
mities. The  descending  cava,  immediately 
before  it  perforates  the  fibrous  coat  of  the  peri- 
cardium, crosses  the  right  branches  close  upon 
the  bifurcation  of  the  trachea;  within  the  peri- 
cardium it  lies  on  the  right  side  of  the  ascend- 
ing portion  of  the  arch  of  the  aorta.  The 
inferior  cava  is  seen  perforating  the  cordiform 
tendon  of  the  diaphragm,  and  almost  imme- 
diately afterwards  it  enters  the  posterior  and 
inferior  angle  of  the  right  auricle.  The  pul- 
monary veins  are  placed  inferior  to  the  two 
branches  of  the  pulmonary  artery.  The  two 
right  pulmonary  veins  pass  behind  the  right 
auricle  to  reach  the  left,  which  they  enter  near 
the  septum  auriculorum. 

Peculiarities  of  the  fatal  heart. — (For  an 
account  of  the  developement  of  the  heart  and 
large  bloodvessels  see  Ovum.)  The  heart  of 
the  foetus  before  the  fourth  month  is  placed 
vertically,  but  towards  that  period  the  apex 
begins  to  turn  towards  the  left  side.  The 
auricular  part  of  the  heart  is  considerably  larger 
in  proportion  than  the  ventricular.  The  relative 
size  of  the  heart  to  the  body  at  birth  differs 
considerably  from  that  of  the  foetus  at  an  earlier 
period  of  its  developement.  According  to 
Meckel  the  relative  size  of  the  heart  to  the 
body  about  the  second  or  third  month  of  uterine 
life  is  1  to  50;  at  birth  and  for  a  few  years 
afterwards  as  1  to  120.  The  greater  size  of  the 
heart  of  the  foetus  seems  to  depend  principally 
upon  the  greater  thickness  of  the  walls  of  its 
cavities.  The  great  disparity  between  the  thick- 
ness of  the  two  sides  so  very  apparent  shortly 
after  birth  does  not  exist  in  the  earlier  periods 
of  uterine  life,  though  also  generally  sufficiently 
well-marked  in  the  foetus  at  the  full  time.  This 
is  explained  by  the  circumstance  that  the  two 
sides  of  the  heart  at  this  period  have  nearly 
equal  obstacles  to  overcome  in  propelling  the 
blood.*  In  the  earlier  stages  of  its  deve- 
lopement the  infundibuliform  portion  of  the 
right  ventricle  is  less  prominent  than  at  a  later 
period.  The  left  ventricle  is  at  first  a  little 
larger  than  the  right ;  at  birth  and  for  a  short 
while  after  they  are  equal.  The  two  auricles 
communicate  with  eacli  other  through  the  fora- 

*  In  two  foetuses,  however,  which  I  lately  exa- 
mined, and  where  I  had  positive  evidence  that 
they  had  not  yet  reached  the  sixth  month  of  utero- 
gestation,  the  difference  between  the  thickness  of 
the  two  ventricles  of  the  heart  was  distinctly 
marked. 


men  ovale.*  This  foramen  is  at  its  maximum 
size  about  the  sixth  month. 

Valve  of  the  foramen  ovale. — This  valve, 
which,  however,  can  scarcely  be  called  a  valve, 
as  it  is  a  provision  for  effecting  the  obliteration 
of  the  foramen  ovale  at  the  time  the  child 
assumes  its  independent  existence,  first  makes 
its  appearance  at  the  lower  part  of  the  foramen 
about  the  third  month,  or,  according  to  Senac 
and  Portal,  about  the  second  month.  It  is 
formed  by  the  inner  membranes  of  the  two 
sides  of  the  heart,  containing  some  muscular 
fibres  between  them,  particularly  at  its  lower 
part.  It  is  of  a  semilunar  form ;  its  convex 
edge  adheres  to  a  greater  or  less  portion  of  the 
margins  of  the  valve  as  its  growth  is  more  or 
less  advanced;  its  concave  margin,  which  is 
free  and  loose,  looks  upwards  and  forwards. 
This  valve  may  be  said  to  belong  almost  exclu- 
sively to  the  left  auricle,  as  it  is  attached  to 
that  margin  of  the  foramen. f  Though  this 
valve  is  of  sufficient  size  at  birth  to  shut  the 
foramen,  yet  its  concave  or  upper  margin  is 
easily  depressed  so  as  to  leave  a  considerable 
interval  between  it  and  the  upper  margin 
of  the  foramen.  We  will  find,  from  the  man- 
ner in  which  the  valve  is  attached  to  the  left 
margin  of  the  foramen,  that  it  is  much  more 
easily  depressed  by  a  current  passing  from  the 
right  auricle  into  the  left  than  in  the  opposite 
direction.  In  fact  any  force  of  this  kind  ap- 
plied in  the  opposite  direction  would  rather 
tend  to  keep  the  valve  applied  to  the  upper 
edge  of  the  opening;  a  circumstance  which 
occurs  after  birth  when  the  blood  flows  along 
the  pulmonary  veins  into  the  left  auricle,  and 
which  must  materially  assist  in  producing  com- 
plete obliteration  of  the  foramen.  The  manner 
in  which  the  blood  passes  between  the  auricles 
through  the  foramen  ovale  in  the  foetus  was  the 
subject  of  a  violent  controversy  in  France  at 
the  termination  of  the  seventeenth  and  the 
commencement  of  the  eighteenth  centuries.  It 
was  first  commenced  between  Meri  on  the  one 
side,  who  had  proposed  a  new  theory  of  the 
foetal  circulation  by  which  the  blood  was  made 
to  pass  from  the  left  auricle  into  the  right,  and 
by  Duverry  and  Fauvery  on  the  opposite  side, 
who  maintained  the  opinion  of  Ilarvey,  and 
which  is  now  universally  adopted,  that  it  passes 
from  right  to  left.  Many  celebrated  anatomists 
and  mathematicians  attached  themselves  to  the 
opposite  parties,  and  at  last  the  controversy 
extended  itself  to  the  neighbouring  kingdoms.  J 

Eustachian  valve. — This  valve,  the  appear- 
ance and  position  of  which  have  been  already 

*  This  opening  is  frequently  termed  trou  de  Botal 
by  the  French  writers  though  described  by  Galen. 

t  This  explains  how  the  depression  (fossa  ovalis), 
marking  in  the  adult  the  position  of  the  valve, 
should  be  better  seen  from  the  right  than  the  left 
auricle. 

|  Those  who  may  be  anxious  to  acquaint  them- 
selves more  fully  with  the  nature  of  this  contro- 
versy and  to  examine  the  arguments  adduced  on 
both  sides  may  consult  the  M  ('moires  de  l'Academie 
for  that  period,  and  Senac's  Traite  de  la  Structure 
du  Cceur,  torn.  i.  p.  369,  ajrd  the  Supplement  in 
torn.  ii. 


600 


HEART. 


pointed  out  in  describing  the  interior  of  the 
right  auricle,  is  also  intimately  connected  with 
the  peculiarities  of  foetal  life.  It  was  discovered 
by  Eustachius  about  the  middle  of  the  six- 
teenth century,  who  contented  himself  by  point- 
ing out  its  position.  Little  attention  was  paid 
to  it  until  the  commencement  of  the  eighteenth 
century,  when  it  was  more  particularly  brought 
into  notice  by  Boerhaave  and  Lancisi,  who 
published  a  new  edition  of  the  works  and 
plates  of  Eustachius,  which  had  then  become 
very  scarce.  Lancisi  supposed  that  this  valve 
prevented  the  blood  of  the  superior  cava  from 
falling  with  too  much  force  upon  the  column 
ascending  by  the  cava  inferior.  Winslow,* 
finding  it  only  perfect  in  the  foetal  state,  and 
having  cause  to  believe  that  its  diminution  kept 
pace  with  the  increase  of  the  valve  of  the 
foramen  ovale,  was  led  to  adopt  the  opinion 
that  its  presence  had  a  special  reference  to  that 
state,  and  believed  that  it  not  only  served  to 
break  the  current  of  the  superior  cava  as  stated 
by  Lancisi,  but  also  opposed  the  regurgitation 
of  the  blood  of  the  auricle  into  the  inferior 
cava.  In  the  absence  of  this  valve  he  supposed 
there  would  arise  two  inconveniences  in  the 
foetus — the  imperfect  intermixture  of  the  con- 
tained blood,  and  the  regurgitation  of  the  blood 
of  the  umbilical  vein  into  the  placenta.  Senacf 
believed  that  the  Eustachian  valve  can  have  no 
effect  in  preventing  the  blood  of  the  cava  supe- 
rior from  falling  upon  the  current  ascending  by 
the  cava  inferior,  and  that  it  must  direct  a  part 
of  the  blood  of  the  cava  inferior  through  the 
foramen  ovale.  SabatierJ  more  particularly 
pointed  out  that  from  the  position  of  this  valve 
passing  from  the  anterior  and  left  part  of  the 
vena  cava  inferior  to  the  left  side  of  the  foramen 
ovale,  and  from  the  situation  of  the  foramen 
ovale  at  the  inferior  part  of  the  auricle,  the 
blood  of  the  cava  inferior  must  be  directed 
through  the  foramen  ovale ;  and  further,  from 
the  difference  in  the  direction  of  the  two  cavae 
themselves — the  superior  looking  downwards, 
forwards,  and  to  the  left  side,  while  the  inferior, 
though  it  is  also  slightly  directed  to  the  left, 
passes  at  the  same  time  upwards  and  back- 
wards, when  combined  with  the  upper  thick 
margin  of  the  foramen  ovale — it  would  neces- 
sarily happen  that  the  blood  of  the  superior 
cava  must  fill  the  right  auricle. 

In  three  injections  of  the  foetal  circulation 
which  I  performed,  where  arrangements  were 
made  to  imitate,  as  far  as  possibly  could  be 
done,  the  manner  in  which  the  two  currents 
flow  into  the  heart  during  the  life  of  the  foetus, 
results  were  obtained  confirmatory  of  the  opi- 
nion of  Sabatier.§  This  arrangement  cannot 
of  course  exist  in  the  early  months  of  uterine 

*  Memoires  de  l'Acad.  Roy.,  annee  1717. 
t  Op.  cit.  torn.  i.  p.  228. 

t  Traite  complet  d'Anatomie,  torn.  ii.  p.  224. 

§  Edinburgh  Medical  and  Surgical  Journal,  1835. 
These  injections  are  also  confirmatory  of  one  made 
by  Kilian,  where  the  fluid  thrown  along  the  aorta 
passed  to  the  head  and  superior  extremities,  and 
that  along  the  pulmonary  artery  to  the  lower  part 
of  the  body. 


life  from  the  imperfect  developement  of  th  e 
heart  itself,  and  in  all  probability  part  only  of 
the  blood  of  the  inferior  cava  is  transmitted 
through  the  foramen  ovale  into  the  left  side  of 
the  heart  for  a  short  time  before  birth.  The 
pulmonary  veins  appear  to  bring  very  little 
blood  to  the  left  side  of  the  heart  until  the  time 
approaches  that  the  foetus  must  necessarily 
assume  an  independent  existence.  The  circu- 
latory apparatus  becomes  gradually  prepared 
for  this  change ; — the  Eustachian  valve  begins 
to  shrink,  the  foramen  ovale  to  diminish  in  size, 
and  a  greater  quantity  of  blood  is  transmitted 
through  the  lungs.  Billard*  has  ascertained 
from  the  examination  of  the  bodies  of  a  great 
number  of  infants  who  died  within  a  few  days 
after  birth,  that  the  foramen  ovale  and  the  other 
circulatory  passages  peculiar  to  the  foetus  are 
generally  shut  about  the  eighth  day  after  birth. 
In  nineteen  infants  who  had  lived  only  one 
day  the  foramen  ovale  was  completely  open  in 
fourteen ;  in  two  it  had  commenced  to  become 
obliterated,  in  the  remaining  two  it  was  com- 
pletely shut.  On  the  subsequent  days  the 
number  of  those  with  the  foramen  shut  con- 
tinued to  increase;  and  in  twenty  examined, 
who  had  died  on  the  eighth  day,  five  only  had 
the  foramen  open. 

Physiology  of  the  heart. 
Mode  of  action  of  the  valves  of  the  heart. — 
While  the  blood  is  rushing  through  the  auri- 
culo-ventricular  openings  during  the  contrac- 
tion of  the  auricles,  the  lips  of  the  mitral  and 
tricuspid  valves  are  separated  from  each  other 
and  thrown  outwards  from  the  axis  of  the 
opening,  and  the  larger  lip  of  both  is  at  this 
time  carried  towards  the  arterial  orifices.  It 
has  generally  been  supposed  that  the  mitral  and 
tricuspid  valves  are,  during  the  systole  of  the 
ventricles,  passively  floated  up  towards,  and 
obstruct  the  auriculo-ventricular  orifices  so  as 
to  prevent  the  free  regurgitation  of  the  blood 
into  the  auricles ;  and  that  the  use  of  the  cordse 
tendmese  is  merely  to  limit  the  movements  of 
the  valves, — to  permit  them  to  be  raised  suffi- 
ciently to  close  the  orifices,  but  at  the  same 
time  to  provide  against  the  otherwise  unavoid- 
ably fatal  consequences  that  would  result  from 
these  unresisting  valves  being  carried  through 
into  the  auricles  by  the  current  of  blood.  Mayo, 
Bouillaud,  and  others  have,  however,  main- 
tained that  the  lips  of  these  valves  are  not 
approximated  in  the  mechanical  manner  just 
stated,  but  by  the  contraction  of  the  musculi 
papillares  of  which  the  cordae  tendineae  are  the 
proper  tendons.  As  the  musculi  papillares 
contract  along  with  the  other  fibres  of  the  ven- 
tricles, the  lips  of  the  valves  are  drawn  towards 
the  axis  of  the  opening,  and  are  closely  applied 
to  each  other,  forming  a  kind  of  cone,  the  apex 
of  which  projects  downwards  into  the  ven- 
tricles. Jt  is  from  the  adoption  of  these  views 
that  Bouillaud  proposes  to  call  these  musculi 
papillares,  the  tensor,  elevator,  or  adductor 
muscles  of  the  valves.    That  the  lips  of  the 

*  Traite  des  Maladies  des  Enfaas  nouveau-nes, 
&c,  p.  557,  1828. 


HEART. 


601 


valves  are  approximated  in  this  manner  appears 
to  me  to  be  the  much  more  probable  opinion; 
for  when  we  examine  the  uniform  position  and 
course  of  the  musculi  papillares  and  chords 
tendineae,  more  particularly  those  of  the  left 
ventricle ;  that  the  chordae  tendineae  pass  from 
each  musculus  papillaris  to  both  lips  of  the 
mitral  valve,  occasionally  crossing  each  other ; 
and  that  the  posterior  or  smaller  lip,  though 
it  may  be  drawn  inwards  so  as  to  meet  the 
larger  and  more  moveable,  is  so  bound  down 
as  to  be  scarcely  capable  in  most  cases  of  being 
floated  up  on  a  level  with  the  orifice ;  and 
further,  when  we  also  remember  that  the  mus- 
culi papillares  contract  at  the  same  time  with 
the  other  fibres  of  the  heart,  we  can  scarcely 
resist  coming  to  this  conclusion.  Besides,  if 
the  lips  of  the  valves  were  floated  up  to  the 
orifice,  a  greater  quantity  of  blood  would  regur- 
gitate into  the  auricles  during  the  systole  of  the 
ventricle  than  in  all  likelihood  takes  place ; 
for  as  the  lips  of  the  valve  must  be  widely 
separated  from  each  other  when  the  systole 
commences,  it  is  evident  that  a  less  quantity 
of  blood  must  have  passed  through  the  orifice 
before  the  lips  are  sufficiently  approximated  to 
obstruct  its  further  passage  when  these  are 
assisted  by  an  active  force,  than  when  they  are 
merely  passively  brought  together  by  the  cur- 
rent of  blood  passing  in  that  direction.  It  has, 
however,  been  supposed  that  the  musculi 
papillares  do  not  contract  with  the  other  fibres 
of  the  ventricles.  Ilaller  states*  that  on  laying 
open  the  heart  he  has  seen  the  muscles  of  the 
valves  contract  during  the  systole  of  the  heart. 
It  may  be  objected  to  this  experiment  that  the 
unusual  stimulus  applied  to  the  heart  in  cutting 
its  fibres  across  may  have  deranged  the  usual 
order  of  its  contractions.  I  have  repeatedly 
opened  the  heart  in  rabbits  and  waited  until  its 
contractions  had  ceased,  and  on  renewing  its 
movements  by  irritating  the  inner  surface  at  a 
distance  from  the  cut  edges,  I  have  observed 
that  the  columns;  carneae  acted  simultaneously 
with  the  other  muscular  fibres  of  the  heart.f  I 
was  also  satisfied  that  the  musculi  papillares 
were  proportionally  more  shortened  during  their 
contraction  than  the  heart  itself  taken  as  a 
whole,  which  is  nothing  more  than  what  we 
would  expect  when  we  remember  that  the  fibres 
of  the  musculi  papillares  are  so  far  free  and 
run  longitudinally,  while  by  far  the  greater  part 
of  the  other  fibres  run  in  a  spiral  manner. 

Haller,  in  relating  his  observations  on  the 
contraction  of  the  musculi  papillares,  makes 
another  statement,  which,  however,  is  decidedly 
adverse  to  this  opinion.  The  chordae  tendineae 
appeared  to  him  to  be  relaxed  during  the  con- 
traction of  the  musculi  papillares. 

It  is  difficult  to  make  satisfactory  observa- 
tions upon  the  effects  of  the  contractions  of  the 

*  Elemcnta  Physiolog.  torn.  i.  p.  390.  Sur  le 
Mouvement  du  sang,  p.  129.  Memoires  sur  la 
Nature  sensible,  torn.  i.  p.  379. 

t  [The  observations  of  the  London  Committee 
appointed  by  the  British  Association  to  examine 
into  the  motions  and  sounds  of  the  heart  confirmed 
this  view  of  the  simultaneity  of  contraction  of  the 
columns;  caruca;  and  ventricular  fibres. — Ed.] 


musculi  papillares  upon  the  tension  of  the 
chordae  tendineae.  In  several  animals  upon 
which  we  attempted  to  ascertain  this,  it  was 
only  when  the  heart  was  acting  languidly  that 
we  could  observe  what  was  likely  to  be  the 
effect  of  the  contraction  of  the  musculi  papil- 
lares on  the  chordae  tendineae  when  they  were 
placed  as  far  as  possible  in  their  natural  rela- 
tion to  each  other.  We  could  never  observe 
that  they  contracted  sufficiently  to  move  the 
valves,  but  they  certainly  rendered  some  of  the 
chordae  tendineae  more  tense.  When,  however, 
we  take  into  account,  that  in  an  experiment  of 
this  kind,  the  valves  are  not  thrown  out  widely 
from  the  orifices  of  the  auriculo-ventricular 
orifices,  the  ventricle  is  not  distended  with 
blood,  the  chordae  tendineae  consequently  not 
put  so  far  on  the  stretch  as  occurs  at  the  com- 
mencement of  the  systole,  and  that  the  con- 
tractions of  the  musculi  papillares  are  languid, 
we  can  easily  perceive  how,  in  the  natural 
systole  of  the  heart,  these  contractions  of  the 
musculi  papillares  should  be  sufficient  to  move 
the  valves  inwards,  though  not  to  such  an  extent 
as  to  apply  them  closely  to  each  other.  The  con- 
traction of  these  musculi  papillares  apparently 
sets  the  valves  in  motion,  and  they  are  subse- 
quently applied  to  each  other  by  the  currents 
of  blood.  It  may  be  supposed  that  if  the  con- 
traction of  these  musculi  papillares  can  render 
the  chordae  tendineae  sufficiently  tense  to  move 
the  valves,  this  would  prevent  the  subsequent 
elevation  of  them  to  obstruct  the  auriculo- 
ventricular  opening.  We  believe,  however, 
that  it  is  only  at  the  commencement  of  the 
systole  that  they  are  sufficiently  tense  to  move 
the  valves,  for  as  the  contraction  proceeds  the 
capacity  of  the  heart  is  so  much  diminished, 
both  in  its  transverse  and  longitudinal  dimen- 
sions, that  they  become  relaxed.  Besides,  if 
we  could  suppose  that  these  musculi  papillares 
are  capable  of  contracting  through  a  sufficient 
space  to  draw  the  valves  together,  this  would 
be  all  that  is  necessary  to  prevent  the  regurgita- 
tion of  the  blood  through  the  auriculo-ventri- 
cular opening.* 

So  convinced,  indeed,  were  the  older  anato- 
mists and  physiologists  that  the  chordae  tendineae 
are  relaxed  during  the  systole  of  the  heart,  and 
of  the  necessity  of  an  accompanying  diminution 
of  the  length  of  the  ventricles  themselves  to 
effect  this,  that  this  argumentadduced  by  Bassuel 
appears  to  have  been  principally  instrumental 
in  deciding  the  once  keenly  controverted  ques- 
tion whether  or  not  the  heart  was  elongated 
during  its  contraction.y 

*  All  these  experiments  upon  the  action  of  the 
columnar  carneae  were  finished  and  the  article 
forwarded  to  London  about  the  middle  of  June, 
1836. 

f  Mr.  T.  W.  King  in  an  elaborate  essay  (Guy's 
Hospital  Reports,  No.  iv.  April  1837,)  has  pointed 
out  what  he  conceives  to  be  a  "  safety-valve  func- 
tion in  the  right  ventricle  of  the  human  heart." 
This  view  is  founded  upon  the  fact  which  he  be- 
lieves that  he  has  ascertained,  "  that  the  tricuspid 
valve,  naturally  weak  and  imperfect,  closes  less 
and  less  accurately,  according  to  the  increasing 
degrees  of  the  ventricular  distention."  From  this 
he  is  "  convinced  that,  in  all  cases  in  which  the 


602 


HEART. 


It  may  be  supposed  that  the  relative  size  of 
the  auriculo-ventricular  orifices  to  the  length  of 
the  lips  of  the  valves  would  not  admit  of  their 
apices  being  brought  together  in  the  form  of  a 
cone  as  described,  but  it  must  be  remembered 
that  from  the  course  of  the  muscular  fibres  in 
the  immediate  neighbourhood  of  those  open- 
ings, their  areas  must  be  diminished  during 
the  systole  of  the  heart.  There  is  at  least  one 
thing  certain  connected  with  the  action  of  these 
valves,  viz.  that  the  contraction  of  the  musculi 
papillares  can  never  cause  the  valves  to  strike 
the  inner  surface  of  the  ventricle  and  produce 
a  sound  as  has  been  supposed. 

The  manner  in  which  the  semilunar  valves 
at  the  origin  of  the  aorta  and  pulmonary  artery 
perform  their  office  is  entirely  mechanical  and 
easily  understood.  During  the  systole  of  the 
heart  they  are  thrown  outwards  from  the  axes 
of  these  vessels ;  but  during  its  diastole,  when 
part  of  the  blood  driven  into  the  artery  would 
fall  back  into  the  ventricles,  these  valves  are 
thrown  inwards  and  obstruct  completely  the 
whole  calibre  of  the  arteries.  In  all  probability 
the  sinuses  of  Valsalva  placed  behind  these 
valves  contain  a  certain  quantity  of  blood  even 
during  the  systole  of  the  heart,  and  this  re- 
acting upon  the  valves  through  the  agency  of 
the  elast.city  of  the  arteries  brought  into  opera- 
tion at  the  termination  of  the  systole,  materially 
assists  in  producing  the  more  rapid  and  certain 
action  of  the  valves. 

Movements  of  the  heart. — The  heart  is  a 
muscle  of  involuntary  motion,  being,  for  the 
wisest  of  purposes,  placed  beyond  the  direct 
control  of  volition.  The  case  of  Colonel 
Townshend*  is  of  too  obscure  a  nature  to 
entitle  us  to  found  upon  it  an  opposite  doc- 
trine, more  particularly  as  it  is  at  direct  variance 
with  every  other  fact  or  observation. 

The  movements  of  the  heart,  when  the  body 
is  at  rest  or  in  a  state  of  health,  proceed  with- 
out our  consciousness.  In  certain  cases  of 
disease  they  are  attended  by  uneasy  feelings, 
but  they  are  never  at  any  time  or  under  any 
circumstances  dependent  upon  sensation  for 
their  continuance. 

It  is  not  so  easy  a  matter  as  may  at  first  be 
imagined  to  ascertain  the  order  of  succession 
in  which  the  different  cavities  of  the  heart  con- 
tract and  dilate,  and  the  different  circum- 
stances which  attend  these  movements,  even 
by  experiments  on  living  animals,  more  par- 
ticularly the  warm-blooded  animals  ;  for  if  the 
heart  when  exposed  is  acting  vigorously  and 
rapidly,  every  one  who  has  examined  for  him- 
self must  have  felt  the  exceeding  difficulty  of 
following  and  analysing  these  movements  by 

right  ventricle  is,  in  any  material  degree,  tempo- 
rarily distended  or  permanently  dilated,  the  heart 
and  lungs  are  relieved  by  a  considerable  reflux  of 
the  ventricle's  contents  into  the  auricle  and  sys- 
temic veins."  In  experiments  upon  the  lower 
animals  I  have  repeatedly  seen  the  right  ventricle, 
when  gorged  with  blood  and  acting  feebly,  empty 
itself  through  an  opening  in  the  jugular  vein. 
Bdinb.  Med.  and  Surg.  Journ.  1836. 

*  Cheyne's  English  Malady,  p.  307.  1734, 
London. 


the  eye.  If,  on  the  other  hand,  the  animal 
has  become  debilitated  and  the  movements  of 
the  heart  languid,  these  are  apt  to  deviate  from 
their  natural  order,  and  to  be  performed  in  an 
irregular  and  unnatural  manner.*  It  is  in  this 
way  that,  we  can  account  not  only  for  the  dis- 
crepant statements  of  the  older  observers,  but 
also  for  the  very  frequent  announcement  of 
new  views  on  this  subject  which  appear  in  the 
medical  periodicals  of  our  own  day.  As  we 
will  find  that  many  of  these  theories  connected 
with  the  physiological  actions  of  the  heart  even 
in  the  present  day,  have  been  founded  upon 
false  notions  of  the  normal  anatomy  and  na- 
tural movements  of  the  organ,  and  only  require 
a  reference  to  these  for  their  full  and  satis- 
factory refutation,  it  will  be  necessary  that  we 
attend  particularly  to  the  manner  in  which 
these  different  contractions  and  relaxations  suc- 
ceed each  other,  and  the  visible  phenomena 
by  which  they  are  accompanied,  as  observed 
by  the  most  accurate  experimenters. 

When  the  heart  of  a  living  animal  is  ex- 
posed and  the  organ  is  acting  in  a  natural 
manner,  the  auricles  are  observed  to  become 
distended  with  blood,  then  to  contract  rapidly 
and  simultaneously,  and  propel  part  of  it  into 
the  ventricles;  this  is  accompanied  with  a 
corresponding  enlargement  of  the  ventricles, 
which  is  immediately  followed  by  their  simul- 
taneous contraction  and  the  propulsion  of  their 
blood  along  the  large  arteries :  then  follows  a 
pause,  during  which  the  auricles  become  gra- 
dually distended  by  the  blood  flowing  along 
the  veins.  When  the  auricles  are  filled,  they 
again  contract,  and  the  same  train  of  pheno- 
mena just  described  occur  in  uniform  succes- 
sion. 

Systole  and  diastole  of  the  auricles. —  The 
contraction  or  systole  of  the  auricles  is  pre- 
ceded by  their  relaxation  or  diastole.  During 
the  diastole  the  auricles  become  distended  with 
the  blood  flowing  along  the  veins.  The  com- 
mencement of  the  diastole  occurs  during  the 
contraction  of  the  ventricles;  the  latter  part 
corresponds  to  the  pause  in  the  heart's  action, 
and  to  the  interval  between  the  recurrence  of 
the  sounds  of  the  heart,  and  is  more  or  less 
long  in  proportion  as  the  blood  flows  more  or 
less  rapidly  along  the  veins. 

The  systole  of  the  auricles  is  performed  with 
great  rapidity  when  the  action  of  the  heart  is 
still  vigorous,  and  appears  to  be  effected  by 
the  simultaneous  contraction  of  all  its  fibres. 
The  terminations  of  the  cavae  and  pulmonary 
veins  are  seen  to  contract  simultaneously  with 
the  fibres  of  the  auricles,  but  sometimes  they 
are  seen  to  contract  previous  to  the  auricles, 
into  which  they  expel  their  blood.  In  the  cold- 
blooded animals  this  contraction  of  the  ter- 
minations of  the  large  veins  extends  over  a 
greater  surface,  and  is  visible  in  the  venae  he- 

*  The  illustrious  Harvey  thus  describes  the  dif- 
ficulties which  he  experienced  in  his  first  attempts 
to  analyse  the  movements  of  the  heart :  "  ita  ut 
modo  hinc  systolem,  illinc  diastolem,  modo  c  con- 
tra, modo  varios,  modo  confusos  fieri  motus  me 
existimarem  cerncre." 


HEART. 


603 


paticae.*  Judging  from  the  number  of  mus- 
cular fibres  which  surround  the  termination  of 
the  pulmonary  veins  in  the  human  species, 
we  would  expect  these  contractions  to  occur  to 
a  greater  extent  in  these  veins  than  in  the  cava?. 
These  contractions  in  the  veins  must  assist  the 
vis  a  tergo,  or  the  force  with  which  the  column 
of  blood  flows  along  the  veins  towards  the 
heart,  in  limiting  the  regurgitation  along  these 
during  the  contraction  of  the  auricles.  This 
regurgitation  along  the  veins  appears  to  be  to 
a  small  extent  only  when  the  circulation  is  pro- 
ceeding in  a  natural  manner,  but  becomes  con- 
siderable where  there  is  any  impediment  to  the 
free  passage  of  the  blood  into  the  ventricles, 
and  when  the  blood  becomes  stagnated  in  the 
veins.  When  the  actions  of  the  heart  are  en- 
feebled, the  contractions  of  the  auricles  are 
slower,  and  may  become  more  or  less  vermi- 
cular, as  I  have  myself  occasionally  observed. 
Two  or  more  contractions  of  the  auricle  may 
also  now  be  necessary  before  the  languid  ven- 
tricle can  be  excited  to  contraction.  When 
the  action  of  the  heart  is  still  more  enfeebled, 
particular  portions  only  of  the  auricles  con- 
tinue to  contract.  According  to  the  obser- 
vations of  Harvey,  Lower,  Senac,  Ilaller,  and 
others,  the  contractions  of  the  auricles  are  per- 
formed with  considerable  force. 

Harvey  states  that  he  has  observed  that  if  the 
finger  is  applied  to  the  ventricles  in  those  cases 
where  the  action  of  the  auricles  continues  after 
the  contractions  of  the  ventricles  have  ceased, 
a  distinct  beat  is  felt  in  the  ventricle  at  each 
stroke  of  the  auricle ;  and  Senac,  in  quoting 
this,  adds  (evidently  from  his  own  observation) 
that  it  is  similar  to  the  pulse  in  the  arteries. 
Senac  also  states  that  if  an  opening  be  made 
into  the  apex  of  the  heart  under  those  circum- 
stances, a  jet  of  blood  rushes  through  it  at 
each  stroke  of  the  auricle.  He,  however, 
admits  that  the  contraction  of  the  auricles  in 
these  cases  is  not  sufficient  to  dilate  sensibly 
the  walls  of  the  ventricles,  but,  of  course,  very 
considerable  allowance  ought  to  be  made  for 
the  enfeebled  state  of  the  auricles  at  this  stage 
of  the  experiment.-)-  In  the  experiments  of 
Dr.  Hope,  Mr.  Carlisle,  M.  Bouillaud,  and 
the  Dublin  Committee  for  investigating  the 
cause  of  the  sounds  of  the  heart,  the  contrac- 
tion of  the  auricles  appeared  to  be  compara- 
tively trifling,  and  was  most  apparent  in  the 
appendices.  From  my  own  observations  upon 
rabbits  and  dogs  I  am  convinced  that  the  au- 
ricles contract  considerably  more  when  the 
movements  of  the  heart  are  proceeding  in  a 
natural  manner,  than  some  of  these  last  expe- 
riments would  lead  us  to  believe,  and  that  this 
contraction  is  not  confined  to  the  appendix, 

*  The  contractions  of  the  different  parts  of  the 
heart  in  cold-blooded  animals  have  been  observed 
to  occur  in  the  following  order  :  first,  the  termin- 
ation of  the  large  veins,  then  the  auricles,  then 
the  ventricles,  and,  lastly,  the  bulb  of  the  aorta. 

f  I  have  convinced  myself  of  the  accuracy  of 
these  statements  of  Harvey  and  Senac  in  expe- 
riments upon  dogs  opened  soon  after  they  had  been 
deprived  of  sensation. 


but  extends  over  the  whole  auricle.  When 
the  circulation  through  the  lungs  becomes  im- 
peded, the  right  ventricle  is  then  unable  to 
empty  itself,  and  the  auricle  of  the  same  side 
(and  this  is  the  one  that  is  most  generally  ob- 
served in  such  experiments)  is  consequently 
impeded  in  its  movements.  The  auricles  do 
not  certainly  exert  the  force  or  contract  to  the 
extent  which  some  have  stated,  do  not  ex- 
pel the  whole  of  their  contents,  and  their 
diastole  is  comparatively  feeble;  but  that  none 
of  the  muscular  fibres  of  the  auricles  are  pas- 
sive, but  exert  a  force  proportionate  to  their 
strength,  we  have  evidence  both  from  expe- 
riment and  the  effects  of  disease.  In  some 
of  those  cases  where  an  impediment  to  the 
passage  of  the  blood  from  the  auricle  to  the 
ventricle  exists,  all  the  muscular  fibres  of  the 
auricles  become  much  increased  in  thickness 
and  in  strength.  As  the  left  auricle  has  natu- 
rally greater  difficulties  to  overcome  in  pro- 
pelling its  blood  than  the  right,  so  we  find  that 
the  left  auricle  is  considerably  more  muscular 
than  the  right.*  The  appendix  from  its  being 
loose,  and  supplied  by  a  band  of  longitudinal 
fibres  drawing  it  backwards,  must  enjoy  a  freer 
motion  than  the  other  parts  of  the  auricle. 

Systole  and  diastole  of  the  ventricles. — 
When  the  heart  is  acting  vigorously,  the  con- 
traction of  the  ventricles  succeeds  immediately 
upon  that  of  the  auricles,  so  that  they  some- 
times appear  continuous ;  or,  in  other  words, 
the  sudden  distention  of  the  ventricles  by  the 
blood  propelled  into  them  during  the  systole 
of  the  auricles  is  rapidly  followed  by  the  con- 
traction of  the  ventricles.  The  systole  of  the 
ventricles  must  occur  during  the  diastole  of  the 
auricles.  As  we  are  only  sensible  of  the  sys- 
tole of  the  ventricles  from  external  examination 
during  life,  the  expression  systole  of  the  heart 
is  always  employed  as  synonymous  with  the 
systole  of  the  ventricles.  When  the  action  of 
the  heart  is  a  little  less  active,  an  apparent  in- 
terval is  observable  between  the  completion  of 
the  contraction  of  the  auricles  and  the  com- 
mencement of  the  contraction  of  the  ventricles, 
— the  irritability  of  the  ventricles  being  at  this 
time  somewhat  impaired,  their  contraction  does 
not  so  quickly  follow  their  sudden  distention. 
The  ventricles  during  their  systole  are  dimi- 
nished in  all  their  dimensions ;  the  apex  is 
drawn  upwards  to  the  base  and  tilted  forwards 
so  as  to  strike  the  parietes  of  the  thorax  be- 
tween the  cartilages  of  the  fifth  and  sixth  ribs.f 

"  In  the  case  mentioned  by  Allan  Burns,  where 
an  ossific  deposit  covered  the  whole  surface  of  the 
ventricles,  so  as  to  entirely,  or  nearly  entirely,  pre- 
vent their  action,  the  auricles  must  have  per- 
formed part  of  their  functions  for  some  time  before 
death.  In  one  of  the  experiments  of  Dr.  Wil- 
liams, of  London,  upon  asses,  he  observed  the 
circulation  along  the  arteries  continue  although 
the  ventricles  were  quiescent,  and  the  auricles 
alone  contracted. 

t  "  Dr.  C.  J.  13.  Williams  has,  in  a  lecture  lately 
published  in  the  Medical  Gazette  (July  28,  1838, 
p.  692,)  pointed  out  that,  during  a  deep  inspira- 
tion, the  ribs  are  elevated  without  raising  the  heart 
in  the  same  degree,  and  the  impulse  may  be  felt 


G04 


HEART. 


The  parietes  of  the  ventricles  at  this  time  are 
firm  and  resisting,  and  present  some  rugae  on 
their  outer  surface.  Mailer*  states  that  though 
the  principal  movement  of  the  ventricles  du- 
ring their  systole  is  from  the  apex  upwards, 
yet  he  has  sometimes  observed  a  slight  but  dis- 
tinct movement  from  the  base  downwards.  The 
contraction  of  the  ventricles  is  performed  with 
great  force,  and,  when  vigorous,  appears  to  be 
accomplished  by  the  simultaneous  action  of  all 
its  fibres ;  but  at  other  times,  when  it  has  be- 
come enfeebled,  it  has  been  observed  to  com- 
mence at  the  apex  and  extend  itself  upwards. 

The  diastole  of  the  ventricles  consists  of  two 
distinct  stages.  The  first,  which  immediately 
follows  its  systole,  is  sudden,  the  apex  being 
pushed  downwards  and  apparently  passing 
deeper  into  the  chest,  and  is  occasioned  by  the 
return  of  the  heart  to  its  state  of  rest.  The 
second  is  also  sudden,  and  attended  by  a  rapid 
but  not  very  extensive  enlargement  of  the  heart 
in  all  its  dimensions.  The  parietes  of  the 
heart  are  soft  and  flaccid,  and  their  external 
surface  smooth  during  their  diastole.  The 
diastole  of  the  heart  is  performed  with  con- 
siderable force,  so  that  Pechlin,  Perrault,  Ham- 
berger,  and  others  long  ago  maintained  that 
this  equally  with  the  systole  is  the  result  of  a 
vital  action.  This  opinion  was  again  revived 
by  Bichat,  Dumas,  and  their  followers,  and  is 
still  introduced  by  some  into  the  discussions 
upon  the  movements  of  the  heart.  Before 
we  can  admit  an  opinion  of  this  kind,  it 
would  be  necessary  that  very  strong  evidence 
be  adduced  in  its  favour,  as  it  is  at  perfect 
variance  with  all  that  we  know  of  the  arrange- 
ment of  the  fibres  of  the  heart,  and  of  the 
laws  of  muscular  contractility .f 

OesterreicherJ  has  performed  the  following 
experiment,  which  appears  nearly  decisive  on 
this  point.  When  a  body  is  placed  on  the 
heart  of  a  frog  heavy  enough  to  press  it  flat, 
but  sufficiently  small  to  allow  the  heart  to  be 
observed,  it  will  be  seen  that  the  body  will  be 
lifted  during  the  contraction  of  the  heart,  but 
that  during  its  extension  it  will  remain  flat. 
From  this  it  appears  that  the  extension  of  the 
heart  after  the  contraction  is  not  a  muscular 
act.  The  diastole  of  the  heart  depends  then 
upon  two  circumstances.  1st,  Upon  the  na- 
tural elasticity  of  the  organ,  which  it  possesses 
in  common  with  every  other  muscle,  and  by 
which  it  instantly  resumes  its  state  of  rest  as 
soon  as  its  contraction  has  ceased.  This,  which 
is  usually  termed  the  relaxation  of  a  muscle  in 
whatever  part  of  the  body  it  occurs,  must  be 
expected  to  be  more  energetic  in  the  heart  than 

below  the  sixth  rib.    On  the  other  hand,  when  the 
ribs  are  depressed,  as  during  a  deep  expiration, 
the  apex  of  the  heart  may  be  felt  beating  between 
the  fourth  and  fifth  ribs." 
*  El.  Phys.  torn.  i.  p.  400. 

t  Scharschmid  supposed  that  certain  pretended 
longitudinal  fibres^by  shortening  the  heart  enlarged 
its  cavities,  while  the  transverse  fibres  by  contract- 
ing separately  diminish  its  capacity. 

t  Muller's  Handbuch  der  Physiologie  des  men- 
schen,  Erster  Band,  p.  163. 


in  the  muscles  of  voluntary  motion,  as  from 
the  arrangement  of  its  fibres  a  great  part  must 
be  more  strongly  compressed.  This  occurs 
during  the  first  of  the  two  stages  into  which 
we  divided  the  diastole.  2d,  Upon  its  sudden 
distention  during  the  contraction  of  theauricles, 
when  we  have  every  reason  to  believe  that  the 
ventricles  are  completely  passive.  This  con- 
stitutes the  second  stage  of  the  diastole.  The 
blood  must  then  pass  from  the  auricles  into 
the  ventricles  during  each  diastole  at  two  dis- 
tinct periods  of  time,  corresponding  to  these 
two  stages.  During  the  first  stage,  or  the  re- 
laxation of  the  ventricles,  it  flows  from  the 
auricles  to  fill  up  the  vacuum  produced  in  their 
interior;  while,  during  the  second  stage,  it  is 
forcibly  propelled  by  the  auricles.  It  would 
be  difficult  to  estimate  the  relative  proportion 
of  these  two  quantities  of  blood.  Those  who 
suppose  that  the  contraction  of  the  auricles  is 
feeble  must  consequently  believe  that  most  of 
the  blood  passes  from  the  auricles  into  the  ven- 
tricles during  the  first  stage. 

It  has  been  long  disputed  whether  or  not  the 
ventricles  empty  themselves  completely  during 
each  systole.  It  is  very  difficult  to  perceive 
anything  like  correct  data  upon  this  point  in 
the  warm-blooded  animals  with  opaque  hearts ; 
but  reasoning  from  analogy,  from  what  we  see 
in  the  cold-blooded  animals  whose  hearts  be- 
come quite  pale  during  each  systole,  (not,  as 
Harvey  supposed,  from  the  blood  being  pressed 
out  of  its  parietes,  but  from  the  blood  in  its 
cavity,  seen  through  its  transparent  sides,  being 
almost  entirely  expelled  during  its  systole,) 
we  would  be  inclined  to  believe -that  little 
blood  remained  after  each  systole  in  the  active 
state  of  the  organ,  while  we  can  easily  sup- 
pose that  a  greater  or  less  quantity  is  left  after 
each  contraction  when  the  organ  is  less  vi- 
gorous. 

It  was  the  subject  of  a  violent  dispute  at  the 
commencement  of  the  last  century  between  the 
Montpellier  and  Parisian  anatomists  and  phy- 
siologists, whether  or  not  the  heart  became 
shortened  or  elongated  during  its  contraction. 
In  all  the  warm-blooded  animals  at  least  it 
undoubtedly  becomes  shortened.*  We  may  at 
the  same  time  state  that  the  obliteration  of  the 
cavity  of  the  ventricle  depends  much  more  upon 
the  approximation  of  its  sides  than  the  drawing 
up  of  the  apex. 

Impulse  of  the  heart. — It  has  been  at  various 
times,  and  still  is  by  some  late  and  modern 
experimenters,f  maintained  that  the  apex  of 
the  heart  strikes  the  parietes  of  the  thorax  during 

*  The  authority  of  Harvey  has  been  quoted  in 
favour  of  the  opinion  that  the  heart  becomes  elon- 
gated during  its  contraction,  and  certainly  in  one 
part  of  his  work  it  is  distinctly  stated,  that  it  is  so 
to  a  certain  extent  :  "  Undique  contrahi  magis 
vero  secundum  latera  ;  ita  uti  minores  magnitu- 
dinis  et  longiuseulum ,  et  collectum  appareat." 

t  Pigeaux,  Stokes,  Burdach,  and  Beau.  Br. 
Corrigan  has,  much  to  his  credit,  publicly  re- 
nounced his  previously  published  opinions  on  this 
question,  after  more  accurate  observations  had  con- 
vinced him  of  his  error. 


HEART. 


605 


its  diastole,  and  not  during  its  systole.  This 
is  in  reality  what  we  would  a  priori  expect, 
for  it  certainly  does  at  first  appear  somewhat 
paradoxical  that  the  heart  should  strike  the 
parietes  of  the  chest  when  the  apex  is  ap- 
proximated to  the  base.  The  concurrent  tes- 
timony of  the  most  accurate  observers  has, 
however,  fully  established  the  correctness  of 
the  fact.  Harvey  observed  it  in  the  human 
body  when  the  heart  had  been  exposed  from 
the  effects  of  disease.*  One  of  the  principal 
arguments  adduced  in  support  of  this  opinion 
by  these  authors  was  drawn  from  the  fact  that 
the  pulse  at  the  wrist  is  not  synchronous  with 
the  impulse  against  the  chest,  an  opinion 
which  had  been  pretty  generally  maintained 
since  the  time  of  Aristotle.  It  is  difficult  to 
be  convinced  of  this  when  the  pulse  is  quick  ; 
but  when  it  is  slow,  and  in  certain  cases  of 
disease  of  the  heart,  it  can  generally  be  satis- 
factorily ascertained.  So  far  then  they  are  right, 
but  in  the  next  and  most  important  step  of  the 
argument  they  fall  into  a  decided  error ;  for 
they  proceed  upon  the  supposition  that  the 
pulse  is  synchronous  in  all  the  arteries  of  the 
body  at  the  same  time,  and  consequently  the 
impulse  of  the  heart  at  the  chest  cannot  be 
synchronous  with  the  flow  of  blood  along  the 
arteries,  or,  in  other  words,  with  the  systole 
of  the  heart.  In  opposition  to  this  opinion, 
Dr.  Youngf  had  previously  shown  upon  the 
principles  of  hydraulics  that  the  pulse  along 
the  arteries  must  be  progressive,  yet  in  general 
so  rapid  as  to  appear  to  arrive  at  the  extremities 
of  the  body  without  the  intervention  of  any 
perceptible  interval  of  time.  And  when  the 
attention  of  medical  men  was  turned  to  this 
subject,  various  observers  soon  ascertained  by 
repeated  experiments  that  the  pulse  could 
be  felt  in  favourable  cases  to  pass  along  the 
arteries  in  a  progressive  manner,  —  that  the 
pulse  in  the  large  arteries  at  the  root  of  the 
neck  and  impulse  at  the  chest  are  synchronous 
or  nearly  so,  that  both  precede  that  at  the  wrist, 
and  more  distinctly  still  that  of  the  dorsal 
artery  of  the  foot.J 

Various  attempts  have  been  made  to  explain 

*  "  Simul  cordis  ipsius  motum  observavimus, 
nempe  illud  in  diastole  introrsum  subduci  et 
retrain  ;  in  systole  vero  emergere  denuo  et  protrudi 
fierique  in  corde  systolem  quo  tempore  diastole  in 
carpo  percipicbatur  :  atque  proprium  cordis  motum 
et  functionem  esse  systolem  :  deniqne  cor  tunc 
pectus  fierique  et  prominulum  esse  cum  erigitur 
sursum."  As  quoted  by  Shebeare,  Pract.  of  Phy- 
sic, vol.  i.  p.  195. 

f  Phil.  Trans.  1809. 

\  Ft  is  interesting  and  curious,  as  shewing  the 
revolution  of  opinions,  to  compare  the  strict  simi- 
larity of  the  arguments  adduced  by  the  modern 
supporters  of  this  doctrine  with  those  maintained 
by  Shebeare  in  1755.  (Practice  of  Physic,  vol.  i. 
p.  193.)  "  This,  however  plausible  it  may  ap- 
pear, cannot  be  the  true  cause  of  it  (impulse  of 
the  heart),  because  then  this  stroke  must  be  during 
the  systole  of  the  ventricles,  which  would  be  syn- 
chronous with  the  diastole  of  the  arteries  ;  whereas 
the  beating  of  the  heart  precedes  the  dilatation  of 
the  arteries,  and  thence  this  stroke  must  be  made 
dining  the  diastole  of  the  ventricles :  thus  the 
diastole  or  distention  of  the  heart  is  the  cause  of 
the  beating  against  the  ribs." 


in  what  manner  the  apex  of  the  heart  is  made 
to  impinge  against  the  parietes  of  the  chest  by 
those  who  maintain  that  it  occurs  during  the 
systole  of  the  ventricles.  Senac  supposed  that 
this  was  principally  effected  by  the  curvature 
of  the  two  large  arteries,  but  principally  of  the 
aorta,  which  arise  from  the  ventricles ;  for  at 
each  stroke  of  the  ventricles  when  an  addi- 
tional quantity  of  blood  is  driven  into  the  large 
arteries,  as  they  are  curved  they  make  an  at- 
tempt to  straighten  themselves;  and  as  this 
takes  place  to  a  slight  extent,  the  heart,  which 
is  attached  to  their  extremities,  ought  to  be 
displaced,  and  its  apex,  which  describes  the 
arc  of  a  circle  greater  than  the  other  parts  of 
the  heart,  is  thus  made  to  impinge  against  the 
walls  of  the  chest.  He  also  believed  that  the 
distention  of  the  left  auricle  with  blood  during 
its  diastole  has  also,  from  its  position  between 
the  spine  and  base  of  the  heart,  the  effect  of 
pushing  the  heart  forwards;  and  this  occurring 
at  the  same  time  with  the  attempt  which  the 
curved  arteiies  make  to  straighten  themselves, 
it  thus  acts  as  a  second  or  subsidiary  cause  in 
tilting  the  heart  forwards*  Though  this  sup- 
posed effect  of  the  curvature  of  the  large 
arteries  has  been  a  favourite  explanation  with 
many  of  the  impulse  of  the  heart  against  the 
chest,  yet  it  really  appears  to  have  little,  if  any, 
influence  in  producing  this.  Shebeare,f  and, 
more  lately,  Dr.  C'orrigan,+  have  shown  that 
the  direction  of  the  curvature  of  the  large  ar- 
teries is  such,  that  if  any  effect  of  this  kind  is 
produced,  the  heart  would  not  be  carried  to 
the  left  side,  but  in  the  direction  of  the  curve, 
which  is  exactly  in  the  opposite  direction. 
Besides  the  tiltmg  forwards  of  the  heart  has 
been  observed  though  no  blood  was  passing 
along  the  large  vessels  at  the  time,  and  the 
same  thing  takes  place  after  the  large  vessels 
have  been  cut  through  and  the  heart  removed 
from  the  body.§  Haller  and  others  have  sup- 
posed that  the  secondary  cause  assigned  by 
Senac, — viz.  the  sudden  distention  with  blood 
of  the  left  sinus  venosus  which  lies  impacted 
between  the  spine  and  left  ventricle, — is  the 
principal  if  not  the  sole  cause  by  which  the 
heart  is  pushed  forwards  against  the  ribs.  In 
confirmation  of  this  opinion  Haller  states  || 
that  if  we  inflate  the  left  auricle  after  having 
opened  the  chest,  we  see  the  point  of  the  heart 
approach  with  vivacity  the  region  of  the  mam- 
ma. As  we  cannot,  however,  under  these  cir- 
cumstances distend  the  auricle  without  also 
distending  the  corresponding  ventricle,  this 
movement  of  the  heart  depends  more  upon  the 
sudden  inflation  of  the  ventricle  than  upon  any 

*  Op.  cit.  torn.  i.  p.  356.  The  cause  of  the  tilt- 
ing motion  of  the  heart  was  also,  at  a  later  period, 
attributed  to  the  curvature  of  the  aorta  and  to  this 
exclusively  by  Dr.  W.  Hunter.  Note  in  John  Hun- 
tor's  Treatise  on  Inflammation,  p.  146,  1794. 

t  Op.  cit.  p.  195. 

%  Dublin  Med.  Trans,  vol.  i.  p.  154. 

§  Dr.  Carson  (Inquiry  into  the  Causes  of  the 
Motion  of  the  Blood,  p.  183,)  maintains  that  no 
proof  can  be  adduced  that  the  curvature  of  the 
aorta  is  rendered  more  straight  during  the  systole 
of  the  heart. 

||  Sur  le  Mouvemcnt  du  Sang,  p.  124. 


606 


HEART. 


distention  of  the  auricle,  as  any  one  may  easily 
satisfy  himself  by  repeating  the  experiment. 
Besides,  the  distention  of  the  auricles  by  the 
blood  flowing  along  the  veins  is  too  gradual  for 
this  sudden  and  rapid  impulse  of  the  heart ; 
nay  more, — the  impulse  may  be  observed  when 
no  blood  is  flowing  into  the  auricles.  Sabatier* 
believed  that  this  impulse  depends  upon  two 
causes, — 1st,  principally  upon  the  distention  of 
the  auricles,  more  particularly  the  left;  and, 
2dly,  upon  the  curvature  of  the  large  arteries. 
Apparently,  however,  perceiving  the  necessity 
of  there  being  a  sudden  distention  of  the  auri- 
cles to  produce  this,  he  supposed  that  this  was 
effected  by  the  auriculo-ventricular  valves.  He 
argued  that,  as  these  valves  during  the  diastole 
of  the  heart  form  a  cone  stretching  from  the 
base  towards  the  point  of  the  ventricle,  which 
is  full  of  blood  when  the  systole  commences, 
when  the  valves  are  carried  upwards  to  ob- 
struct the  auriculo-ventricular  orifices,  this 
blood  is  pushed  before  them  into  the  auricles, 
producing  a  reflux  into  the  auricles,  which, 
with  the  blood  flowing  along  the  cava;  and  pul- 
monary veins,  causes  a  sudden  distention  of  the 
auricles,  which  pushes  the  ventricle  forwards. f 
Meckel  appears  to  have  adopted  the  opinions 
of  Sabatier.  We  need  not  repeat  our  objec- 
tions to  this  explanation.  Dr.  Alison,  per- 
ceiving the  insufficiency  of  all  these  explana- 
tions, has  for  a  considerable  time  past  sug- 
gested in  his  lectures,  that  this  might  be  ex- 
plained by  the  arrangement  of  the  fibres, 
"  more  particularly  by  the  irregular  cone  which 
they  form,  being Jluttened  posteriorly,  and  by 
the  consequent  greater  mass  of  fibres  on  the 
anterior  surface."  More  lately  Mr.  Carlisle  + 
has  also  attempted  to  explain  this  by  the  greater 
length  of  the  anterior  fibres  of  the  heart  than 
of  the  posterior.  As  the  shape  of  the  ventricles 
is  an  oblique  cone,  and  as  they  have  their  long- 
est sides  in  front,  he  argues,  "  that  it  is  a 
law  of  muscular  contraction  that  fibres  are 
shortened  during  their  contraction  in  proportion 
to  their  length  when  relaxed.  For  instance,  if 
a  fibre  one  inch  long  lose  by  contraction  one- 
fourth  of  its  length,  or  one  quarter  of  an  inch,  a 
fibre  two  inches  in  length  will  lose  one  inch  by 
contractions  of  equal  intensity.  The  apex  then 
does  not  approach  the  base  in  the  line  of  the 
axis  of  the  ventricles,  but  is  drawn  more  to  the 
side  of  the  longer  fibres,  that  is,  towards  the 
front,  thus  producing  the  tilting  forwards." 
We  believe  that  it  may  be  proved  on  mechani- 
cal principles,  that  though  the  anterior  and  left 
surfaces  of  the  ventricles  are  considerably  longer 
than  those  on  the  posterior  and  right,  yet  during 
their  contraction,  when  they  are  drawn  towards 
their  fixed  attachments,  if  the  fibres  are  of 
equal  thickness,  the  apex  will  be  drawn  up 
nearly  in  the  diagonal  of  the  two  forces,  and 
that  if  any  tilting  upwards  of  the  apex  take 
place,  this  will  be  only  to  a  small  extent,  and 

*  Traite  complct  d'Anatomie,  torn.  ii.  p.  230. 

t  Dr.  Bostock  has  failed  of  his  usual  accuracy 
in  detailing  the  opinion  of  Sabatier  on  this  ques- 
tion. 

X  Transactions  of  British  Scientific  Association, 
vol.  iii.  Dublin  Journal  of  Medical  Science,  vol.  iv. 


be  quite  insufficient  to  account  for  the  impulse 
felt  at  the  chest.  We  must  therefore  look  to 
some  other  circumstances  besides  a  mere  diffe- 
rence in  length  of  the  two  surfaces  to  account 
for  this.  Mr.  Alderson*  has  ingeniously  at- 
tempted to  apply  the  law  of  action  and  reaction 
between  bodies, — one  of  considerable  import- 
ance in  mechanical  philosophy,  and  upon  which 
Barker's  centrifugal  mill  has  been  constructed. 
Unfortunately,  however,  for  this  explanation, 
the  axes  of  the  large  arteries  and  the  direction 
in  which  the  apex  is  tilted  do  not  by  any  means 
accord.  Dr.  Hope's  supposition  that  "  the  re- 
tropulsion  of  the  auricular  valves"  may  assist 
in  producing  this  impulse,  "  as  these  act  on  a 
column  of  blood  which  offers  a  greater  resist- 
ance than  the  weight  of  the  heart,  the  action  is 
reflected  on  the  organ  itself  and  impels  it  for- 
wards," is,  on  the  other  hand,  completely  op- 
posed to  the  law  that  action  and  reaction  are 
the  same.  As  well  may  a  man  attempt  to  pro- 
pel a  boat  by  standing  in  the  stern,  and  push 
with  an  oar  against  the  prow.  Dr.  Filhos  attri- 
buted the  impulse  to  the  spiral  turns  of  the 
fibres  at  the  apex  of  the  heart  attempting  to 
straighten  themselves  during  their  contraction, 
and  so  raise  themselves  suddenly  and  throw 
themselves  forwards.  The  objections  to  this 
explanation  are  so  palpable  that  they  must 
occur  to  every  one.  Since  the  tilting  of  the 
apex  of  the  heart  forwards  is  observed  after  the 
blood  has  ceased  to  flow  through  its  cavities,  it 
is  obvious  that  we  must  look  for  the  cause  of 
this  in  the  arrangement  of  the  muscular  fibres 
themselves,  though  it  may  be  difficult  to  point 
out  that  particular  arrangement.  It  appears  to 
me  that  the  distribution  of  some  of  the  strong 
bands  of  fibres,  the  course  of  which  I  have 
already  described  when  treating  of  the  muscu- 
lar tissue  of  the  heart,  may  satisfactorily  account 
for  it.  We  there  pointed  out  that  several  strong 
bands  of  fibres  arise  from  the  base  of  the  septum 
between  the  ventricles,  pass  downwards  and 
form  part  of  the  septum,  then  emerge  from  the 
anterior  longitudinal  groove  {fig.  274,  d ),  and 
wind  round  in  a  spiral  manner  to  form  both  the 
anterior  and  posterior  part  of  the  lower  portion 
of  the  heart.  On  entering  the  apices  of  the 
ventricles,  (principally  the  left,)  the  fibres  are 
scattered  over  their  inner  surfaces,  and  while  a 
great  number  of  them  go  directly  to  be  inserted 
into  the  tendinous  rings,  others  form  part  of  the 
columnar  carnea?.  We  have  thus  strong  bands 
of  fibres  attached  by  one  extremity  (their  septal 
extremity)  to  the  base  of  the  ventricles  at  a 
point  pretty  far  posterior,  while  at  the  other  ex- 
tremity many  of  the  fibres  are  loose,  or  at  least 
only  attached  to  the  tendinous  rings  through 
the  media  of  the  chordae  tendinea?  and  valves, 
which  must  admit  of  a  certain  degree  of  con- 
traction of  these  fibres  before  they  become  tense. 
At  each  systole  of  the  heart  when  these  fibres 
act,  it  is  evident  that  the  tendinous  rings  must 
form  the  fixed  points  towards  which  all  these 
fibres  contract ;  and  since  they  are  by  one  ex- 
tremity all  closely  and  directly  connected  to  a 

*  Quarterly  Journal  of  Science,  &c.  vol.  xviii. 
p.  223. 


fixed  attachment,  viz.  the  tendinous  rings,  while 
by  their  other  extremity  part  only  are  directly 
attached  to  the  tendinous  rings,  the  other  part 
being  loose,  or  at  least  only  connected  to  the 
tendinous  rings  through  the  lax  chorda?  tendi- 
nea  and  valves,  it  must  follow  that  the  force 
with  which  the  contraction  takes  place  towards 
the  septal  extremity  must  preponderate  over 
the  other.  If  these  bands  of  fibres  had  been  as 
closely  connected  to  the  tendinous  rings  at  the 
one  extremity  as  at  the  other,  then  the  force  of 
the  contraction  towards  both  would  have  been 
equal ;  but  since  this  is  not  the  case,  the  apex 
must  be  carried  forwards  at  the  same  time  that 
it  is  drawn  upwards  towards  the  base.  This 
forward  motion  may  also  probably  be  assisted 
by  another  arrangement  of  the  same  fibres 
which  we  have  been  describing;  for  some  of 
these  muscular  bands  are  attached  by  their 
inner  extremity  to  the  anterior  part  of  the  left 
auriculo-tendinous  ring,  so  as  to  form  loops,  the 
greater  part  of  which  lie  more  in  front  than  be- 
hind the  axis  of  the  heart,  and  may  have  a  ten- 
dency, when  in  a  state  of  contraction,  to  draw 
the  apex  forwards  and  upwards.  Now  when 
we  remember  that  by  this  elevation  of  the  apex 
forwards,  the  heart,  before  placed  obliquely, 
now  becomes  more  horizontal,  and  conse- 
quently more  approximated  to  the  walls  of  the 
chest, — the  more  particularly  as  the  transverse 
diameter  of  the  chest  diminishes  rapidly  as  we 
proceed  from  below  upwards,  we  believe  that 
we  have  here  sufficient  to  account  for  this  im- 
pulse against  the  chest.  As  the  proximity  of 
the  apex  of  the  heart  to  the  chest  is  affected  by 
the  position  of  the  body,  as  we  have  already 
pointed  out,  this  circumstance  ought  to  be  at- 
tended to  in  judging  of  the  strength  of  the  im- 
pulse of  the  heart. 

What  parts  of  the  heart  most  irritable. — The 
inner  surface  of  the  heart  is  considerably  more 
irritable  than  the  outer.  In  experiments,  when 
the  heart  has  become  quiescent,  and  refuses  to 
obey  a  stimidus  applied  to  the  outer  surface,  it 
frequently  contracts  readily  for  a  short  time 
after  this  when  air  is  introduced  into  its  cavi- 
ties, or  when  any  other  stimulant  is  applied  to 
its  inner  surface.  After  death  the  different 
cavities  of  the  heart  generally  lose  their  contrac- 
tility in  the  following  order,  the  left  ventricle, 
the  right  ventricle,  the  left  auricle,  and  last  of 
all  the  right  auricle.*  And  as  the  heart  is  gene- 
rally the  part  of  the  body  which  shews  the  latest 
evidences  of  contractility,  the  right  auricle  has 
long  received  the  name  of  ultlmum  moriens. 
Ualler  supposed  that  the  greater  persistence  of 
contractility  in  the  right  side  of  the  heart  over 
the  left  might  depend  on  the  circumstance  that 
the  right  side  of  the  heart  generally  contains  a 
greater  or  less  quantity  of  blood  after  death, 
while  the  left  side  is  generally  empty.    In  this 

*  There  is  occasionally  considerable  variety  ob- 
served in  the  order  in  which  the  different  cavities 
lose  their  contractility  after  death.  The  left  ven- 
tricle has  been  seen  to  contract  after  the  right  auri- 
cle ;  and  Haller  has  observed  in  experiments  upon 
cats  the  irritability  of  the  left  auricle  first  cease. 
In  experiments  upon  dogs  I  have  seen  the  ventri- 
cles contract  after  the  auricles  had  ceased  to  do  so. 


607 


HEART. 

manner  the  inner  surface  of  the  right  side  of  the 
heart  is  subject  after  death  to  the  presence  of  a 
stimulant  from  which  the  left  side  is  compara- 
tively free.    He  put  this  opinion  to  the  test  by 
performing  repeatedly  the  following  experi- 
ment*   He  emptied  the  right  side  of  the  heart 
by  the  section  of  the  pulmonary  artery  and 
venae   cava,   having  previously  retained  the 
blood  of  the  left  side  by  passing  a  ligature 
around  the  aorta.    The  experiment  succeeded 
many  times  :  the  right  auricle  remained  per- 
fectly immoveable,  and  the  only  motion  which 
the  right  side  retained  arose  from  the  connexion 
of  its  fibres  with  those  of  the  left  ventricle. 
The  left  auricle  retained  its  movements  for  a 
certain  time,  the  ventricles  during  a  longer 
period,  sometimes  even  for  two  hours.  He  adds, 
we  thus  transfer  from  the  right  auricle  to  the 
left  ventricle  the  property  of  being  the  last 
living  part  in  the  body,  in  preserving  for  it 
during  a  longer  period  the  irritation  produced 
by  the  contact  of  blood.    These  experiments 
of  Haller  certainly  shew  that  the  left  side  of 
the  heart  will  continue  to  contract  longer  than 
the  right  where  it  is  subjected  to  a  stimulant 
of  which  the  other  is  deprived  ;  but  they  do  not 
entitle  us  to  conclude  that  the  persistence  of 
their  contractility  is  the  same  when  placed  un- 
der similar  circumstances.    We  have  every 
reason  for  believing  that  the  right  auricle  is  the 
part  of  the  heart  which  last  loses  its  contracti- 
lity.   Indeed  Haller  himself  confesses,  that  if 
any  part  of  the  heart  remains  longer  contractile 
than  another,  it  is  the  right  auricle.  Nysten,f 
who  performed  a  number  of  experiments  upon 
the  comparative  persistence  of  the  irritability 
in  the  different  contractile  parts  of  the  body  in 
the  human  species,  after  decapitation  by  the 
guillotine,   and  when  the  heart  was  conse- 
quently emptied  of  its  blood,  obtained  the  fol- 
lowing results  upon  the  order  in  which  the  dif- 
ferent parts  of  the  heart  lose  their  contractility  : 
— 1st,  the  left  ventricle,  the  contractility  of 
which  is  annihilated  much  more  quickly  than 
that  of  the  other  organs  ;  2d,  the  right  ventri- 
cle, the  movements  of  which  generally  continue 
more  than  an  hour  after  death ;  3d,  the  two 
auricles,  the  right  being  of  all  the  parts  of  the 
heart  that  which  preserves  for  the  longest  time 
its  contractile  power. 

The  stimulant  used  in  these  experiments  was 
galvanism.  The  greater  persistence  of  the  con- 
tractility in  the  right  auricle  over  the  other  parts 
of  the  heart  has  been  observed  by  other  experi- 
menters, after  it  had  been  cut  from  the  body, 
and  consequently  without  any  contained  blood. 
The  particular  part  of  the  auricle  which  last 
loses  its  contractility  varies  in  different  cases. 
Sometimes  the  appendix  is  found  contracting 
when  the  rest  of  the  auricle  is  quiescent;  at 
other  times,  and  perhaps  more  frequently,  those 
parts  of  the  auricle  around  the  entrance  of  the 
venaj  cava?  retain  their  contractility  longest. 


*  Sur  le  mouvement  du  sang,  p.  172.  Similar 
experiments  were  performed  by  Walther  with  the 
same  results  :  Experimenta  de  vivis  animalibus, 
p.  11,  as  quoted  by  Burdach. 

t  Rechcrches  de  Physiologie,  &c.  p.  321. 


608 


HEART. 


Harvey  and  some  of  the  older  anatomists  ob- 
served the  movements  of  the  venae  cava  to 
continue  in  some  of  the  lower  animals  after  the 
auricles  had  ceased  to  move.  The  apex  of  the 
ventricles  frequently  remains  longer  contractile 
than  the  rest  of  the  ventricle.  Haller  suggested 
that  this  might  depend  on  the  remaining  blood 
gravitating  to  the  apex,  and  there  acting  as  a 
stimulant. 

Duration  of  contract  Mitt/  after  death. — In 
the  cold-blooded  animals  the  heart  may  be 
made  to  contract  fourteen,  twenty,  thirty-four 
hours,  or  even  longer  after  death.  In  warm- 
blooded animals  the  heart  remains  contractile 
for  a  much  shorter  period  after  death  than  in 
cold-blooded  animals.  Haller  found  the  heart 
contractile  in  a  warm-blooded  animal  in  one 
case  four  hours  after  death,  and  in  another 
seven  hours.  He  sometimes  observed  it  to 
cease  before  the  vermicular  motion  of  the  intes- 
tines. Wepfer  found  it  irritable  in  a  dog  six 
hours  after  death.  Nysten,  who  attended  par- 
ticularly to  this  subject,  found  in  one  of  his 
experiments  on  the  human  subject,  that  the 
ventricles  refused  to  contract  upon  the  applica- 
tion of  galvanism  one  hour  after  decapitation, 
while  the  auricles  continued  contractile  for 
seven  hours  five  minutes  after  death.*  In  ano- 
ther case  the  right  auricle  was  still  contractile 
eight  hours  after  death  ;f  and  in  a  subsequent 
case  which  he  relates,  it  remained  contractile  in 
the  neighbourhood  of  the  entrance  of  the  supe- 
rior cava  sixteen  hours  and  a  half  after  death. J 
In  the  Mammifera,  Nysten  found  that  the  left 
ventricle  often  refused  to  contract  thirty  minutes 
after  death  ;  that  the  right  ventricle  retained  its 
contractility  two  hours,  and  sometimes  longer, 
while  the  right  auricle  was  not  quiescent  upon 
the  application  of  the  galvanism  until  eight 
hours  after  death. 

He  found  it  to  vary  in  birds  according  to  the 
degree  of  muscular  activity  which  they  enjoyed 
during  life.  In  those  of  high  flight,  and  which 
exercise  great  muscular  contractility  during  life, 
and  have  a  rapid  circulation,  as  the  sparrow- 
hawk,  the  irritability  of  the  heart  and  other 
muscles  becomes  much  more  speedily  exhaust- 
ed than  in  those  the  movements  of  which  are 
comparatively  slow  and  feeble, as  in  most  domes- 
tic fowls.§  Nysten  supposes  that  the  explana- 
tion of  the  greater  persistence  of  contractility  of 
the  right  ventricle  over  the  left  lies  in  the  cir- 
cumstance that  the  left  acts  with  greater  vigour 
during  life,  thus  referring  it  to  the  important 
general  law  which  he  has  established  by  his 
experiments  upon  the  comparative  excitability 
of  the  muscular  tissue  in  the  various  classes  of 
animals,  that  the  duration  of  the  contractility 
after  death  is  in  the  inverse  ratio  of  the  muscu- 
lar energy  developed  during  life.||    Before  we 

»  Op.  cit.  p.  316. 
f  Page  318. 

i  In  these  experiments  all  the  other  parts  of  the 
body  lost  their  contractility  before  the  right  auricle. 
§  Op.  cit.  p.  349. 

||  Dr.  Marshall  Hall  (Phil.  Trans.  1832)  has 
more  lately  laid  it  down  as  a  general  law  that  the 
irritability  of  the  heart  and  other  muscles  is  in  the 
inverse  ratio  of  the  oxygen  consumed  in  respiration. 


could  admit  this  explanation,  it  would  be  ne- 
cessary to  show,  what  we  believe  it  will  be 
found  impossible  to  do,  that  the  left  ventricle, 
apart  from  its  greater  quantity  of  muscular  fibre, 
exerts  greater  strength  or  exhibits  more  ener- 
getic contractions  during  life  than  the  right 
ventricle.  In  young  animals,  immediately  after 
birth,  the  contractility  of  the  heart  continues 
longer  after  death  than  in  the  adult  animal. 
We  would  expect  this  to  be  most  apparent  in 
those  which  are  born  with  their  eyes  shut,  as 
puppies  and  kittens,  and  in  those  birds  which 
are  hatched  without  feathers,  since  these  ani- 
mals at  that  period  of  life  approach  in  their 
physiological  conditions  to  the  cold-blooded 
animals.     There  is  a   curious  circumstance 
stated  by  Mangili,  and  confirmed  by  Dr.  Mar- 
shall Hall,  connected  with  the  hybernation  of 
animals,  that  if  those  mammalia  which  hyber- 
nate  are  killed  while  under  a  state  of  lethargy, 
the  heart  and  other  muscles  remain  contractile 
for  a  longer  period  than  when  they  are  killed 
in  a  state  of  activity,  thus  resembling,  when 
under  the  influence  of  this  lethargy,  in  this  as 
in  many  other  respects,  the  physiological  con- 
dition of  the  cold-blooded  animals.    The  con- 
tractions of  the  heart  may  frequently  be  renewed 
by  the  application  of  warmth  after  they  have 
apparently  ceased.    I  have  repeatedly  observed 
the  fact  which  has  been  stated  by  Haller  and 
Nysten,  that  when  any  of  the  cavities  of  the 
heart  become  congested  with  blood,  their  con- 
tractility becomes  arrested,  and,  in  their  opi- 
nion, extinguished.*    I  have  also  found  that 
unloading  the  right  side  of  the  heart  soon  after 
the  congestion  has  taken  place,  which  can  be 
done  in  many  cases  by  opening  the  external 
jugular  vein,  acts  as  a  valuable  adjuvant  under 
certain  circumstances  in  renewing  the  heart's 
action.    These  it  would  be  out  of  place  to  dis- 
cuss here ;  but  I  may  state  that  it  appears  to 
me  to  be  principally  useful  in  certain  cases  of 
poisoning,  in  asphyxia,  and  after  the  accidental 
entrance  of  air  into  the  veins.    Since  the  intro- 
duction of  a  considerable  quantity  of  air  into 
the  veins  produces  death  by  mechanically  ar- 
resting the  movements  of  the  right  side  of  the 
heart,  we  believe  that  circumstances  may  occur 
in  which  the  surgeon  may  be  justified  in  intro- 
ducing a  tube  into  one  of  the  large  veins  pass- 
ing into  the  upper  part  of  the  chest,  and  suck- 
Various  experimenters  distinctly  show  that  as  we 
descend  in  the  scale  of  animals  the  quantity  of  oxy- 
gen consumed  diminishes,  and  that  Birds  consume 
more  than  Mammalia.     Dr.   Edwards   has  also 
shown  that  the  young  of  the  Mammalia  deteriorate 
the  atmospheric  air  less  rapidly  than  the  adult  ani- 
mals ;  and  the  experiments  of  Mangili  and  Prinella 
prove  that  hybernating  animals,  when  in  a  state  of 
lethargy,  consume  exceedingly  little  oxygen,  so 
that  there  is  evidently  some  relation  between  irri- 
tability and  the  quantity  of  oxygen  consumed  in  re- 
spiration ;  but  for  the  proof  that  the  irritability  is 
exactly  in  the  inverse  ratio  of  the  respiration,  we 
must  wait  for  Dr.  Marshall  Halt's  promised  experi- 
ments. 

*  Haller  supposed  that  this  was  effected,  as  must 
be  if  allowed  to  continue  for  any  length  of  time, 
by  the  too  great  distension  of  the  muscular  fibres, 
in  the  same  manner  as  distension  of  the  bladder 
produces  paralysis  of  its  fibres. 


HEART. 


C09 


ing  the  frothy  blood  from  the  right  side  of  the 
heart.  It  is  also  necessary  to  remember  this 
circumstance  in  experimenting  upon  the  length 
of  time  during  which  the  heart  remains  con- 
tractile after  death,  as  the  division  or  non-divi- 
sion of  the  large  veins  at  the  root  of  the  neck 
in  laying  open  the  thorax  may  considerably 
modify  the  results.* 

For  the  probable  force  exerted  by  the  heart, 
the  share  which  the  heart  has  in  carrying  on  the 
circulation,  and  the  probable  quantity  of  blood 
expelled  at  each  contraction,  see  the  article 
Circulation. 

Frequency  of  the  heart's  action. — The  fre- 
quency of  the  heart's  action  is  considerably 
modified  by  age,  condition  of  the  other  functions 
of  the  body  at  the  time,  by  mental  emotions,  and 
by  the  original  constitution  of  the  individual. 
Its  movements  are  influenced  by  very  slight 
muscular  exertion,  and  the  extent  of  this  appears 
to  vary  at  different  times  of  the  day.  In  the 
foetus  its  movements  are  rapid,  being  about 
140  in  the  minute.  At  birth  it  is  from  130  to 
140;  at  one  year  115  to  130;  second  year 
100  to  115;  third  90  to  100;  seventh  85  to 
90;  fourteenth  80  to  85;  middle  age  70  to 
75;  in  very  old  age  50  to  (35.  The  heart's 
action  generallysympathises  powerfully  with  the 
other  organs  of  the  body,  and  this  has  always 
been  regarded  as  a  most  important  and  necessary 
guide  in  the  detection  and  cure  of  diseases. 

It  becomes  strong  and  rapid  in  some  cases  of 
inflammation,  while  in  others  it  becomes  rapid 
and  feeble.  It  becomes  quicker  after  eating 
and  slower  during  sleep.  It  is  much  increased 
in  frequency  during  bodily  exertion.  In  cases 
of  great  general  debility  it  becomes  very  quick 
and  feeble.  It  becomes  more  rapid  and 
weaker  during  inspiration,  slower  and  stronger 
during  expiration. 

It  is  an  important  fact  that  when  the  con- 
tractility of  the  heart  is  much  enfeebled  by 
extensive  injuries  of  the  central  organs  of  the 
nervous  system  or  of  the  other  parts  of  the  body, 
(as  when  a  limb  is  extensively  crushed,)  its 
contractions  are  not  only  much  weaker,  but  are 
also  greatly  increased  in  frequency.  It  is  also 
worthy  of  remark  that  such  injuries  do  not  pro- 
duce convulsive  movements  in  this  organ.  The 
effect  which  severe  injuries  and  certain  inflam- 
matory affections  have  in  greatly  debilitating  or 
even  destroying  the  contractility  of  the  heart  is 
a  fact  of  great  practical  importance,  as  it  not 
only  explains  the  cause  of  the  most  alarming 
symptoms  in  such  cases,  but  also  points  out  the 
most  appropriate  remedies  to  avoid  the  chief 
tendency  to  death.  To  this  cause,  for  example, 
we  are  to  attribute  the  rapid  and  feeble  pulse, 
in  concussion  of  the  brain,  in  extensive  mecha- 
nical injuries,  the  shock  after  operations,  exten- 

*  Edinburgh  Medical  and  Surgical  Journal,  1836. 
When  I  performed  these  experiments,  I  was  not 
aware  that  I  had  been  anticipated  to  a  certain  ex- 
tent by  Mr.  Coleman.  (Wilson  on  the  Blood,  &c. 
p.  131.)  It  is  very  possible  that  the  sinuses  upon 
the  inferior  cava  and  hepatic  veins  in  the  seal  may, 
besides  answering  other  purposes,  have  the  effect 
of  preventing  this  mechanical  distension  of  the 
right  side  of  the  heart. 

VOL.  II. 


sive  burns,  peritonitis,  &c.  It  is  very  fortunate 
that  the  contractions  of  the  heart  become  more 
frequent  when  its  contractility  becomes  en- 
feebled. If  the  heart  under  these  circumstances 
had  required,  as  we  would  a  priori  expect,  the 
presence  of  a  greater  quantity  of  blood  to 
stimulate  it  to  contraction,  instead  of  a  smaller 
quantity,  as  is  actually  the  case,  what  would 
have  been  the  consequence  ?  It  is  evident 
that  since  the  resistance,  under  ordinary  cir- 
cumstances, which  the  heart  has  to  overcome  in 
contracting,  is,  according  to  a  well-known  hy- 
drostatic law,  in  proportion  to  the  extent  of  the 
area  of  the  inner  surface  of  the  cavities  of  the 
heart  at  the  commencement  of  their  contraction, 
(each  square  inch  of  surface,  according  to  the 
experiments  of  Hales,  having  a  pressure  upon 
it  nearly  equal  to  four  pounds,)  the  more  fre- 
quent contractions,  where  there  is  a  smaller 
quantity  of  blood  present  in  the  heart  at  the 
commencement  of  each  contraction,  will  not 
demand  the  same  degree  of  muscular  force  for 
their  performance,  as  if  these  had  been  less 
frequent.  If,  when  the  contractility  of  the 
heart  became  debilitated,  the  presence  of  a 
greater  quantity  of  blood  than  usual  in  its 
interior  had  been  necessary  to  stimulate  it  to 
contraction,  and  if  the  area  of  the  inner  surface 
of  the  cavities  of  the  heart  be  in  proportion  to 
the  quantity  of  blood  contained  there,  it  is 
apparent  that  the  movements  of  the  heart  would 
have  been  much  more  rapidly  and  frequently 
arrested  when  its  contractility  became  enfeebled, 
than  they  are  under  the  actual  arrangement. 

The  influence  of  mental  emotions  upon  the 
movements  of  the  heart  requires  no  illustration, 
for  this  is  so  universally  experienced  that  in 
common  language  the  heart  is  considered  to  be 
the  seat  of  the  affections  and  passions,  and  this 
has  had  a  powerful  influence  upon  the  phrase- 
ology of  all  languages. 

In  sanguine  temperaments  the  heart  gene- 
rally contracts  morefrequently  than  in  phlegmatic 
temperaments.  In  women  it  is  also  generally 
a  little  quicker  than  in  men. 

It  varies  very  much  in  different  classes  of 
animals. 

Burdach*  has  given  the  following  table  col- 
lected from  numerous  sources,  as  an  approxi- 
mative valuation  of  the  frequency  of  the  heart's 
action  in  various  animals. 

Number  of  pulsations  in  a  minute.^ 


In  the  Shark    7 

Mussel   15 

Carp   20 

Eel    24 

Snake    34 

Horse    36 

Caterpillar    36 

Bullock    38 

•  Physiologie,  vol.  iv.  p.  251. 
t  We  cannot  consider  the  number  of  pulsations 
of  the  heart  in  a  minute  given  in  the  above  table 
as  by  any  means  quite  satisfactory.    The  number 


of  pulsations  in  the  ox  and  horse  is  given  on  the 
authority  of  Vetcl  in  Froriep,  Notizen,  t.  xxiv.  p. 
112.  Other  observers  state  the  number  of  pulsa- 
tions in  a  minute  at  from  38  to  52  in  the  horse,  and 
from  64  to  70  in  the  ox. 

2  S 


CIO 


HEART. 


Ass  '..  50 

Crab   50 

Butterfly   60 

Goat   74 

Sheep    75 

Hedgehog    75 

Frog   77 

Marmot   ,   90 

Locust   90 

Ape   9o 

Dormouse    105 

Cat    110 

Duck   110 

Rabbit   120 

Menoculus  Caster    120 

Pigeon   130 

Guinea-pig   140 

Hen   140 

Bremus  terrestris   140 

Heron   200 

Menoculus  pulex   200 


For  the  effects  of  the  respiration  upon  the 
contractions  of  the  heart,  and  the  influence  of 
the  circulation  of  dark  blood  upon  its  irrita- 
bility, see  Asphyxia. 

The  cause  of  the  motion  of  the  heart. — The 
motion  of  the  heart,  and  the  constancy  and 
regularity  of  its  movements,  are  circumstances 
so  remarkable  that  they  could  not  fail  early  to 
excite  a  deep  interest  among  medical  philo- 
sophers when  they  had  once  turned  their 
attention  to  the  explanation  of  vital  phenomena. 
When  we  contemplate  the  heart  commencing 
its  movements  at  an  early  period  of  foetal 
existence,  and  never  resting  from  its  apparently 
unceasing  toil  until  the  latest  moments  of  life, 
and  when  we  remember  the  uniform  and  regu- 
lar manner  in  which  all  its  actions  are  accom- 
plished—all conspiring  for  the  proper  per- 
formance of  the  deeply  important  functions 
assigned  to  it,  we  are  at  first  impressed  with  the 
idea  that  it  is  regulated  by  laws  different  from 
similar  textures  of  the  body,  and  altogether 
peculiar  to  itself.  It  must  have  been  under 
the  influence  of  similar  impressions  that  the 
older  medical  philosophers  approached  this 
subject,  and  it  is  in  this  manner  only  that  we 
can  account  for  many  of  the  strange  specula- 
tions on  the  heart's  action  which  they  have  left 
recorded. 

We  find  one  sect  attempting  to  explain  it  by 
a  peculiar  innate  fire.  Sylvius,  the  head  of  the 
chemical  sect,  had  recourse  for  its  explanation 
to  an  effervescence  excited  by  the  intermixture 
of  the  old  and  alkaline  blood  with  the  acid 
chyle  and  acid  pancreatic  lymph.*  Descartes 
supposed  that  a  constant  succession  of  explosions 
occurred  in  the  heart  from  steam  generated 
there,  which  propelled  the  blood  through  the 
body.  Stahl  got  at  once  out  of  the  difficulty 
by  affirming  that  the  heart  was  more  particu- 
larly under  the  guidance  of  the  anima  or  soul. 
But  we  cannot  here  dwell  longer  on  these  ob- 

*  In  the  same  manner  Borelli  says,  "  Constat 
ex  dietis  immediatam  causam  motivam  cordis  esse 
ebullitionem  fermativam  tartarei  succi  sanguinei 
excitatam  a  commistione  succi  spirituosi  a  nervis 
instillati."    Be  Motu  Animalium,  p.  97. 


solete  and  to  us  in  the  present  time  almost 
incredible  opinions,  and  the  only  use  to  which 
they  are  now  applicable  is  to  serve  as  beacons 
to  keep  us,  in  all  our  inquiries  into  the  pheno- 
mena of  living  bodies,  within  the  strict  path  of 
facts  and  observation,  and  to  forcibly  impress 
upon  us  into  what  strange  and  fatal  errors  even 
the  brightest  intellects  may  fall,  when  they 
leave  the  inductive  method  of  investigation, 
and  wander  into  the  alluring  but  dangerous 
regions  of  hypothesis.  And  the  effects  of  these 
errors  are  only  the  more  to  be  dreaded  as  they 
are  often  clothed  in  the  most  seductive  in- 
genuity. It  ought  also  still  more  forcibly  to 
inculcate  upon  us  the  important  truth,  which, 
though  generally  in  our  mouths,  is  not  unfre- 
quently  forgotten  in  practice, — that  as  the 
material  world  and  all  which  it  contains  have 
been  placed  by  the  Author  of  Nature  under 
arbitrary  and  fixed  laws,  it  is  impossible  to  ex- 
tend our  knowledge  of  these  by  theorizing  in 
the  closet,  and  that  this  can  only  be  effected  by 
the  patient  interrogation  of  Nature  herself. 

It  was  not  until  the  time  of  Senac  and 
Haller  that  accurate  notions  began  to  be  enter- 
tained on  the  nature  of  the  heart's  action. 

The  cause  of  the  movements  of  the  heart  is 
distinctly  referable  to  the  same  laws  which 
regulate  muscular  contractility  in  other  parts  of 
the  body,  only  modified  to  adapt  it  for  the  per- 
formance of  its  appropriate  functions.  Like 
all  the  other  muscles  it  is  endowed  with  irrita- 
bility, which  enables  it  to  contract  upon  the 
application  of  a  stimulus.  The  ordinary  and 
natural  stimulus  of  the  heart  is  the  blood, 
which  is  constantly  flowing  into  its  cavities. 
The  greater  irritability  of  the  inner  surface  over 
the  outer  is  evidently  connected  with  the 
manner  in  which  the  stimulus  is  habitually 
applied.  When  the  blood  is  forced  on  more 
rapidly  towards  the  heart,  as  in  exercise,  its  con- 
tractions become  proportionally  more  frequent; 
and  when  the  current  moves  on  more  slowly, 
as  in  a  state  of  rest,  its  frequency  becomes  pro- 
portionally diminished.  If  the  contractions  of 
the  heart  were  not  dependent  upon  the  blood, 
and  their  number  regulated  by  the  quantity 
flowing  into  its  cavities,  very  seiious  and  in- 
evitably fatal  disturbances  in  the  circulation 
would  soon  take  place. 

As  the  heart  continues  to  contract  often  for  a 
very  considerable  time  after  the  venaa  cavae 
have  been  tied,  and  after  the  blood  has  ceased 
to  pass  through  its  cavities,  or  after  it  has  been 
removed  from  the  body,  this  has  been  supposed 
by  some  to  indicate  that  there  is  something  in 
the  heart's  structure  or  in  its  vital  properties 
which  enables  its  movements  to  proceed  inde- 
pendent of  all  other  circumstances.  But  in  all 
these  cases  a  stimulus  has  been  applied  in  some 
form  or  other  to  the  heart.  If  the  heart  has 
been  allowed  to  remain  in  its  place,  though  the 
circulation  of  the  blood  may  have  come  to  a 
stand,  part  of  it  may  yet  remain  in  the  different 
cavities  of  the  organ  ;  or  if  the  pericardium  has 
been  opened,  the  impression  of  the  external 
atmosphere  may  act  as  a  stimulus.  The  expe- 
riments of  Walther  and  Haller  formerly  men- 
tioned upon  the  comparative  irritability  of  the 


HEART. 


611 


two  sides  of  the  heart,  and  the  different  results 
obtained  when  the  one  side  of  the  heart  was 
emptied  of  blood,  and  when  it  was  retained  in 
the  other,  are  sufficient  to  shew  the  effect  which 
the  presence  of  blood  in  the  cavities  of  this 
organ  has  upon  the  continuance  of  its  action 
after  the  circulation  has  ceased.  If  the  heart 
has  been  removed  from  the  body  and  emptied 
of  its  blood,  it  must  naturally  follow  that  its 
different  cavities  will  be  tilled  with  atmospheric 
air ;  and  it  has  been  well  ascertained  that  this 
acts  as  a  very  powerful  stimulant  upon  the 
inner  surface  of  the  heart.*  Every  circumstance 
connected  with  these  experiments  is  in  exact 
conformity  with  the  opinion  that  the  movements 
of  the  heart  are  only  called  into  action  by  the 
application  of  a  stimulant.  Thus,  when  the 
irritability  of  the  heart  becomes  more  languid, 
and  when  the  blood  or  the  atmospheric 
air  in  its  cavities  becomes  insufficient  to 
raise  it  to  contraction,  strong  and  energetic 
movements  may  still  generally  be  excited  by 
having  recourse  to  a  more  powerful  stimulant, 
such  as  the  prick  of  a  scalpel  or  the  application 
of  galvanism.  Since  the  heart  is  highly  en- 
dowed with  irritability,  various  other  mild  fluids 
besides  the  blood  are  capable  of  exciting  it  to 
contraction.  As  every  organ,  however,  has  its 
irritability  adapted  for  the  function  which  it  is 
destined  to  perform,  so  we  find  that  the  heart, 
the  central  organ  of  the  circulation,  is  most 
fitly  called  into  action  by  the  blood,  its  appro- 
priate and  natural  stimulant. 

In  examining  the  nature  of  the  irritability  of 
the  heart,  and  contrasting  it  with  that  of  the 
voluntary  muscles,  we  must  not  compare  its 
contractions  with  those  excited  by  volition  in 
the  muscles  of  voluntary  motion,  for  these  last 
are  evidently  modified  by  the  nervous  influence 
for  an  obvious  purpose  ;  but  let  us  observe  both 
when  placed  under  similar  circumstances,  and 
irritated  by  the  application  of  the  same  stimu- 
lant applied  to  the  muscles  themselves,  and  we 
will  find  that  they  only  differ  in  this, — that  in 
the  voluntary  muscles  each  successive  appli- 
cation of  the  stimulant  is  generally  followed  by 
a  single  contraction,  while  in  the  heart  it  is 
followed,  except  when  the  contractility  is 
much  impaired,  by  several  consecutive  con- 
tractions alternated  with  relaxations.  This  ten- 
dency to  successive  contractions  is  also  observed, 
though  not  to  the  same  extent,  in  the  muscular 
coat  of  the  intestines. 

We  must  admit,  however,  that  the  contrac- 
tions of  the  heart  proceed  under  circumstances 
where  it  is  difficult  to  point  out  the  presence 
of  any  sufficient  stimulus,  and  where,  to  account 
for  their  continuance,  we  are  almost  obliged  to 
have  recourse  to  the  supposition,  that  there  is 
some  innate  moving  power  in  the  heart  itself. 
It  has  been  stated,  for  example,  that  the  move- 

*  Peyer,  Brunner,  and  Hallcr  have  seen  the  con- 
tractions of  the  heart  renewed  by  blowing  air  into 
the  cava  ascendens.  Wepfer  and  Steno  produced 
the  same  effect  by  inflation  of  the  thoracic  duct. 
Ennian  states  that  he  once  observed  the  renewal 
of  the  heart's  action  in  the  human  subject  by 
blowing  air  into  the  thoracic  duct.  Vide  Senac,  torn, 
i.  p.  326. 


ments  of  the  heart  will  proceed  under  the  ex- 
hausted receiver  of  an  air-pump.  I  have 
repeatedly  placed  under  the  bell-glass  of  an 
air-pump  the  heart  of  a  frog  when  removed  from 
the  body  and  emptied  of  its  blood,  and  I  could 
never  satisfy  myself  that  the  frequency  or 
strength  of  its  contractions  was  at  all  affected 
by  the  withdrawal  or  renewal  of  the  air ;  and 
though  it  might  be  urged  that  the  air  is  only 
rarefied,  not  entirely  removed,  in  the  best  ex- 
hausted receiver  of  an  air-pump,  and  that  con- 
sequently in  such  experiments  a  stimulant  still 
existed  in  the  presence  of  the  rarefied  air,  yet 
I  would  not  consider  this  explanation  of  the 
continuance  of  its  contractions  by  any  means 
satisfactory.  In  these  experiments  there  is  ano- 
ther source  of  stimulation  present  which  ought 
to  be  taken  into  account,  for,  as  I  shall  after- 
wards shew,  the  slightest  movement  of  the 
heart,  such  as  that  caused  by  its  contraction, 
upon  the  surface  upon  which  it  is  placed  when 
removed  from  the  body,  is  sufficient,  from  the 
great  irritability  of  the  organ,  to  act  as  a  stimu- 
lant upon  it.  If  these  external  stimuli  appear 
to  be  insufficient  to  account  for  the  persistence 
of  the  contractions  of  the  heart  under  the  cir- 
cumstances we  have  mentioned,  we  may  have 
recourse  to  another  explanation  drawn  from  the 
mechanical  structure  of  the  organ ;  for  it  is 
possible,  as  has  been  suggested  by  Dr.  Alison, 
that  from  the  peculiarly  convoluted  arrangement 
of  the  fibres,  the  outer  may,  during  the  con- 
traction of  the  organ,  pinch  or  stimulate  the 
inner,  and  so  cause  this  tendency  to  repeated 
contractions  from  one  application  of  a  stimu- 
lant. We  do  not,  however,  consider  that  we 
have  succeeded  perfectly  in  accounting  for  the 
continuance  of  the  contractions  of  the  heart 
under  all  circumstances,  but  we  are  unwilling 
to  admit  the  existence  of  any  peculiar  innate 
and  unknown  agency  in  the  production  of  any 
phenomenon,  until  it  is  satisfactorily  established 
that  it  cannot  be  accounted  for  on  the  known 
laws  which  regulate  similar  phenomena  in  the 
same  texture  in  other  parts  of  the  body.  And 
it  must  also  be  remembered  that  these  move- 
ments of  the  heart  have  only  been  observed 
when  its  contractility  was  still  comparatively 
vigorous,  and  where  sources  of  stimulation 
were  still  present.  We  ought,  besides,  to  be 
the  more  cautious  in  admitting  the  existence 
of  this  innate  moving  power,  since  it  is  in 
opposition  to  a  well-known  law  in  the  animal 
economy, — that  though  the  various  tissues  of 
an  organized  body  are  endowed  with  certain 
vital  properties,  yet  the  application  of  certain 
external  and  internal  stimuli  is  necessary  to 
produce  their  manifestations  of  activity.  In 
fact  it  is  from  the  action  and  reaction  of  these 
tissues  and  excitants  upon  each  other,  that  the 
phenomena  of  life  result.* 

*  The  remarks  which  we  have  made  above, 
illustrating  the  great  length  of  time  which  the  heart 
will  continue  to  contract  after  being  removed  from 
the  body,  and  when  all  communication  between  the 
nerves  ramified  in  its  substance  and  the  sympathetic 
ganglia  and  the  central  organs  of  the  nervous  sys- 
tem have  been  cut  oft,  when  taken  along  with  the 
equally  well  ascertained  fact,  that  its  contractions 

2  S  2 


612 


HEART. 


Upon  what  does  this  irritability  of  the  heart 
depend  ? — This  has  been  one  of  the  most  keenly 
agitated  questions  in  physiology,  as  a  great  part 
of  the  experiments,  and  much  of  the  reasoning 
upon  the  nature  of  muscular  irritability,  have 
been  furnished  by  this  organ.  As,  however, 
the  general  doctrines  entertained  on  this  subject 
have  already  been  fully  discussed  under  the 
article  Contractility,  we  shall  here  confine 
ourselves  to  a  few  of  the  leading  facts  connected 
with  it  which  have  a  special  reference  to  the 
heart.  The  two  principal  questions  on  this 
point  since  the  time  of  Haller  have  been,  whe- 
ther does  it  depend  upon  nervous  influence  ? 
or  is  it  a  property  of  the  muscular  fibre  itself 
independent  of  the  nerves  ? 

•  We  have  seen  that  the  nerves  distributed 
upon  the  heart  are  the  par  vagum  and  sympa- 
thetic. Numerous  experimenters  have  removed 
portions  of  the  par.  vagum  on  both  sides  of  the 
neck  without  the  slightest  diminution  of  the 
strength  of  the  contractions  of  the  heart.  These 
experiments  we  have  frequently  performed  with 
the  same  results.    There  can  now  be  no  doubt 
that  the  sudden  death  which  occasionally  fol- 
lows this  operation  is  not  to  be  attributed  to  the 
cessation  of  the  heart's  action,  as  some  of  the 
older  experimenters  believed,  but,  as  Legallois 
has  shewn,  it  depends  upon  an  arrestment  of 
the  movements  of  the  muscles  attached  to  the 
arytenoid  cartilages.    Portions  of  the  sympa- 
thetic have  also  been  destroyed  in  the  middle 
of  the  neck  without  any  effect  upon  the  con- 
traction of  the  heart,  except  what  could  be 
sufficiently  accounted  for  by  the  pain  of  the 
incisions  and  the  terror  of  the  animal.    A  por- 
tion of  both  of  the  sympathetic  and  pneumo- 
gastric  nerves  may  be  removed  in  the  neck 
with  the  same  results;  in  fact  we  cannot,  in 
the  dog  and  most  quadrupeds,  cut  the  par 
vagum  in  the  middle  of  the  neck  without  also 
dividing  the  sympathetic.     Magendie  affirms 
that  all  the  sympathetic  ganglia  of  the  neck, 
along  with  the  first  dorsal,  may  be  removed 
without  any  sensible  derangement  of  the  parts 
to  which  their  nerves  are  distributed.  Brachet* 
supposes  that  the  reason  why  the  excision  of  the 
sympathetic  ganglia  in  the  neck  does  not  always 
arrest  the  heart's  action,  is  because  there  is 
another  source  of  nervous  influence  for  the 
cardiac  nerves  placed  below  this  in  the  cardiac 
plexus  or  ganglion.    He  accordingly  put  this 
opinion  to  the  test  of  experiment,  and  he  as- 
sures us  that  the  total  destruction  of  the  cardiac 
plexus  was  followed  by  the  sudden  and  perma- 
nent arrestment  of  the  heart's  action.  Now 

may  be  readily  increased  or  renewed  under  those 
circumstances,  by  mild  excitants  applied  to  its  inner 
surface,  are  completely  opposed  to  the  supposition 
that  the  heart  is  called  into  contraction  in  a  manner 
similar  to  those  sympathetic  movements  more  lately 
described  under  the  term  excito-motary.  Though 
this  mode  of  explanation  may  be  considered  quite 
legitimate  when  applied  to  those  sympathetic  move- 
ments which  do  not  require  the  intervention  of  the 
brain  for  their  performance,  such  as  deglutition, 
respiration,  &c,  it  is  certainly  pushing  the  doctrine 
far  beyond  its  proper  limits  to  apply  it  to  the 
explanation  of  the  movements  of  the  heart. 

*  Du  systeme  nerveux  ganglionairc..  p.  120. 


when  we  consider  the  nature  of  such  an  ex- 
periment as  this,  with  the  chest  of  the  animal 
laid  open,  the  respiration  arrested,  and  the 
heart  exposed  during  the  time  the  experimenter 
is  searching  and  tearing  for  the  plexus  placed 
deep  behind  the  aorta  and  pulmonary  artery, 
and  which  would  require  a  considerable  time 
to  display  even  in  the  dead  body  when  unem- 
barrassed by  the  movements  of  the  heart,  we 
must  be  more  astonished  that  the  action  of  the 
heart  had  not  completely  ceased  before  the  ex- 
periment was  finished,  than  that  it  should  have 
continued  so  long.  Besides,  even  allowing  that 
this  experiment  could  be  relied  upon,  we  have 
sufficient  evidence,  from  the  facts  stated  above, 
to  entitle  us  to  conclude  that  the  heart  is  not 
dependent  for  its  movement  upon  any  influence 
constantly  transmitted  along  its  nerves  from  the 
central  organs  of  the   nervous  system, — the 
brain  and  spinal  marrow.    Brachet  is  himself 
obliged  to  admit,  from  other  experiments  which 
he  performed,  that  the  division  of  the  sympa- 
thetic at  the  lower  part  of  the  neck  is  not  suffi- 
cient to  arrest  the  heart's  action,  so  that  this 
experiment  is  intended  to  shew  that  its  irrita- 
bility depends  upon  the  ganglia  of  the  sympa- 
thetic itself.    The  independence  of  the  irrita- 
bility of  the  heart  upon  the  brain  and  spinal 
marrow  can  be  very  satisfactorily  proved  in 
another  manner.    The  occurrence  of  acephalous 
monsters,*  and  the   experiments  of  Wilson 
Philip,!  CliftjJ  and  Brachet§  demonstrate  that 
the  brain  or  spinal  marrow  may  be  naturally 
wanting  ;  that  one  or  both  of  them  may  be 
removed  entirely,  or  destroyed  in  small  portions 
at  a  time,  without  arresting  the  heart's  action. 
We  may  here  observe  that  the  experiments  of 
Legallois, ||  Wilson  Philip,  Wedemeyer,1f  Bra- 
chet, and  many  others,  in  which  the  action  of 
the  heart  was  arrested  by  crushing  large  portions 
of  the  brain  or  spinal  marrow,  though  they  do 
not  prove  the  dependence  of  the  irritability  of 
the  heart  upon  the  brain  and  spinal  cord,  at 
least  shew,  what  the  effects  of  mental  emotions 
upon  the  movements  of  the  heart  had  already 
pointed  out,  that  it  can  be  influenced  to  a  great 
and  most  important  extent  through  these  organs. 
The  advocates  for  the  dependence  of  the  irrita- 
bility of  the  heart  upon  the  nerves  appear  to 
have  pretty  generally  abandoned  the  opinion 
that  this  is  derived  from  the  central  organs  of 
the  nervous  system,  and   now  maintain  the 
doctrine,  which  was  more  prominently  deve- 
loped by  Bichat,  that  this  is  derived  from  the 
sympathetic,  the  ganglia  of  which,  according 
to  him,  are  independent  sources  of  nervous 
influence.     From  the  manner  in  which  the 
sympathetic  is  distributed  upon  the  heart,  it  is 

*  The  heart  is  generally  though  not  always  ab- 
sent in  acephalous  monsters. 

f  Experimental  Inquiry  into  the  vital  functions. 

X  Phil.  Trans.  1815. 

§  Systeme  nerveux  ganglionaire. 

||  Legallois  performed  these  experiments  on  the 
spinal  cord  alone,  and  supposed  he  had  proved 
that  the  movements  of  the  heart  were  dependent 
upon  that  portion  of  the  nervous  system. 

K  Physiol.  Untersuchungen  iiber  das  Nerven- 
systcm,  &c.  p.  235. 


HEART. 


613 


perfectly  impossible  to  insulate  that  organ  from 
the  nerve  and  experiment  upon  it ;  but  we 
think  we  are  justified  in  concluding  from  ob- 
servations and  experiments  derived  from  other 
sources,  that  in  all  probability  the  contractility 
of  the  heart  depends  upon  a  property  possessed 
by  the  muscular  fibre  itself  without  any  neces- 
sary intervention  of  its  nerves.  The  possibility 
of  exciting  or  increasing  the  action  of  the  heart 
by  stimuli  applied  to  its  nerves  has  been  mixed 
up  with  this  question.  Though  it  must  be 
admitted  that  mechanical  and  chemical  stimu- 
lants applied  to  a  considerable  surface  of  the 
central  organs  of  the  nervous  system  quicken 
the  heart's  action,  yet  experimenters  have  gene- 
rally acknowledged  that  these  stimulants  applied 
to  the  nerves  of  the  heart  produce  no  effect 
upon  its  movements.  Burdach,*  however, 
maintains  that  he  lias  quickened  the  heart  of  a 
rabbit  deprived  of  sensation  by  applying  caustic 
potass  to  the  trunk  of  the  sympathetic,  or  its  in- 
ferior cervical  ganglion.  That  the  heart  can  be 
excited  to  contraction  by  the  application  of 
galvanism  has  had  many  supporters,  and  many 
celebrated  names  are  arranged  both  on  the 
affirmative  and  negative  sides  of  the  question. 
That  the  movements  of  the  heart  may  be  in- 
creased or  renewed  by  the  application  of  gal- 
vanism as  the  experiment  is  usually  performed, 
there  can  be  no  reasonable  doubt ;  for  if  one 
wire  is  placed  upon  the  nerve  and  the  other 
upon  the  heart,  the  moist  nerve  will  act  as  a 
conductor  to  the  electricity,  and  the  effect  pro- 
duced will  be  the  same  as  if  the  stimulant  had 
been  applied  to  the  substance  of  the  heart  itself. 
Nysten  admits  that  movements  of  the  heart 
were  excited  by  the  galvanism  when  one  of  the 
wires  was  applied  to  one  of  the  large  arteries 
from  which  all  the  visible  filaments  of  the 
nerves  had  been  dissected  off.  Dr.  C.  Holland,! 
in  a  number  of  experiments,  satisfied  himself 
that  the  tissues  of  the  body  conduct  galvanism 
with  so  much  facility,  that  the  heart's  action 
could  readily  be  excited,  when  one  wire  was 
placed  upon  the  heart  and  the  other  in  the  nose, 
mouth,  and  even  among  the  moist  food  in  the 
stomach.  I  have  performed  similar  experiments 
with  the  same  results.  Humboldt  and  Brachet 
assert  that  they  have  quickened  the  movements 
of  the  heart  by  applying  both  wires  to  one  of 
the  cardiac  nerves.  If  these  and  the  experi- 
ments of  Burdach  could  be  relied  upon,  they 
would  be  sufficient  to  prove  that  the  heart  could 
be  occasionally  stimulated  through  the  cardiac 
nerves,  but  the  negative  experiments  on  the 
other  side  are  so  numerous,  and  the  sources  of 
fallacy  in  judging  in  this  manner  of  the  relative 
quickness  of  the  heart's  action  between  one 
time  and  another  so  obvious,  that  we  must  be 
allowed  to  distrust  them  unless  they  should  be 
confirmed  by  other  accurate  observers. 

Constancy  of  the  heart's  action. — The  con- 
stancy of  the  heart's  action  is  more  apparent 
than  real.  After  each  contraction  a  state  of 
relaxation  follows.     The  relative  duration  of 

*  Traite  de  Physiologic,  torn.  vii.  p.  74,  traduit 
par  Join  dan. 

t  Experimental  Inquiry,  &t.  p.  275. 


the  contraction  of  the  auricles  and  ventricles, 
according  to  Laennec,  appears  to  be  as  fol- 
lows : — a  third  at  most,  or  a  fourth  or  a  little 
less  by  the  systole  of  the  auricles  ;  a  fourth  or 
a  little  less  by  the  state  of  quiescence ;  and  the 
half  or  nearly  so  by  the  systole  of  the  ventricles. 
From  this  he  calculates  that  the  ventricles, 
when  the  heart  is  acting  with  its  usual  frequency, 
rest  twelve  hours  out  of  the  twenty-four,  and 
that  in  those  individuals  in  whom  the  pulse  is 
naturally  below  50,  it  must  be  in  a  state  of 
relaxation  sixteen  hours  out  of  the  twenty-four.* 
Now  this  is  a  degree  of  contraction  of  which 
many  muscles  of  the  body  are  probably  suscep- 
tible, such  as  the  muscles  which  support  the 
trunk  when  we  sit  or  walk,  and  which  some, 
as  the  diaphragm  and  intercostals,  generally 
perform. 

Regularity  of  the  heart's  movements. — The 
regularity  of  the  heart's  movements,  so  essential 
to  the  welfare  of  the  animal,  has  appeared, 
even  to  many  modern  physiologists,  to  be  inti- 
mately connected  with  some  peculiarity  in  its 
structure.  We  are  inclined,  however,  to  agree 
with  Haller,  that  this  is  perfectly  explicable  on 
the  known  laws  of  muscular  contractility 
in  other  parts  of  the  body.  The  regularity  of 
the  heart's  action  was  another  fertile  subject  of 
hypothesis  to  the  older  physiologists  ;  and  even 
in  the  present  day  we  find  the  term  "  organic 
instinct''  employpd  to  designate  it. 

The  contractions  of  the  heart  take  place  in 
the  order  in  which  the  blood  flows  into  its 
different  cavities;  and  if  the  blood  be  the  habi- 
tual stimulant  upon  which  its  movements 
depend,  this  is  exactly  what  we  would  expect. f 
The  blood  forced  in  greater  quantity  into  the 
auricles  by  the  contraction  of  the  termination 
of  the  cava;  and  pulmonary  veins,  stimulates 
the  auricles  to  contract  and  propel  an  additional 
quantity  into  the  ventricles  ;  and  this,  acting  as 
a  stimulant  upon  the  ventricles,  excites  them  to 
contract  and  drive  the  blood  into  the  arteries, 
when  the  same  series  of  phenomena  is  renewed 
and  repeated  in  the  same  succession. 

The  continuance  of  the  heart's  action  after 
the  circulation  has  ceased,  we  have  already 
attempted  to  explain  ;  and  if  these  contractions 
depend  upon  the  presence  of  a  stimulus,  they 
must  evidently  be  in  the  same  order  as  in  the 
natural  state  of  the  organ,  as  these  have  not 
been  interrupted.  The  continuance  of  the  re- 
gular order  of  the  contractions  of  the  heart 
after  its  removal  from  the  body  can  in  general, 
we  think,  be  satisfactorily  accounted  for  by 
the  substitution  of  a  new  stimulant  for  that 
of  the  blood ;  the  cavities  are  then  occu- 
pied with  air  instead  of  blood,    and  each 

*  We  have  "not  here  given  Laennec's  calculations 
of  the  relative  duration  of  the  contraction  and 
relaxation  of  the  auricles,  as  they  must  be  founded 
on  false  data — on  the  supposition  that  the  second 
sound  of  the  heart  marked  the  duration  of  the  con- 
traction of  the  auricles. 

t  This  was  also  the  doctrine  maintained  by  Se- 
nac,  op.  cit.  torn.  i.  p.  325.  Senac,  however,  was 
opposed  to  the  doctrine  of  Haller,  that  the  contrac- 
tility of  the  heart  was  a  property  inherent  in  the 
muscular  fibre,  and  independent  of  the  nerves, 
Tom.  i.  p.  451. 


614 


HEART. 


contraction  of  the  auricle  must  force  an  ad- 
ditional quantity  into  the  ventricle,  and  this, 
though  small  in  quantity,  may  be  quite  suffi- 
cient to  excite  the  ventricles  to  contraction, 
when  the  irritability  is  not  too  much  impaired.* 
It  is  only  in  this  manner,  taken  along  with  the 
greater  irritability  of  the  internal  surface  over 
the  external,  that  we  can  explain  the  observa- 
tion made  by  Dr.  Knox  in  the  course  of  his 
experiments  upon  the  irritability  of  the  heart 
in  fishes,  where,  when  the  irritability  was  nearly 
exhausted,  contractions  excited  in  the  auricle 
were  sometimes  followed  by  contractions  of  the 
ventricle,  when  irritation  of  the  outer  surface  of 
the  ventricle  itself  produced  no  effect.f  Cer- 
tainly, under  ordinary  circumstances,  this  regu- 
larity of  the  heart,  so  necessary  for  the  proper 
performance  of  its  functions,  is  a  marked  fea- 
ture in  its  action  ;  but  that  it  is  not  either  ne- 
cessarily connected  with  its  structure  or  vital 
properties,  but  depends  solely  on  the  manner 
in  which  its  stimulant,  the  blood,  is  applied,  is 
proved  by  various  facts.  1st.  The  movements 
of  the  auricles  and  ventricles  generally  cease  at 
different  times  after  death  ;  and  though  the 
auricles  much  more  frequently  continue  to  con- 
tract after  the  ventricles,  yet  several  accurate 
experimenters  have  observed  the  left  auricle 
become  quiescent  before  its  corresponding 
ventricle.];  2dly.  When  the  movements  of 
the  ventricle  have  ceased,  while  the  auricles 
continue  to  contract,  the  ventricle  may  generally 
be  excited  to  vigorous  contractions  by  the  ap- 
plication of  a  powerful  stimulus.  3dly.  When 
the  irritability  of  the  heart  becomes  somewhat 
languid,  two,  three,  or  sometimes  six  or  seven 
contractions  of  the  auricle  may  take  place  be- 
fore the  ventricles  are  roused  to  contraction  ; 
the  evident  deduction  from  which  is,  that  the 

*  When  the  heart  has  ceased  to  contract,  it  may 
frequently  be  called  into  pretty  vigorous  action  by 
opening  one  of  the  large  veins,  and  blowing  some 
air  into  its  cavities. 

t  I  have  repeatedly  attempted  to  ascertain  if  the 
circumstances  here  described  as  sometimes  occurring 
in  the  cold-blooded  animals  could  be  observed  in 
the  warm-blooded  animals,  but  without  success. 
In  one  experiment  upon  the  heart  of  a  rabbit,  after 
all  the  movements  of  the  ventricles  had  ceased, 
but  where  they  could  still  be  readily  excited  by  the 
application  of  a  stimulant,  we  were  convinced  that 
contraction  of  the  auricle,  when  excited  by  stimu- 
lation applied  to  itself  alone,  was  sometimes  fol- 
lowed by  contaction  of  the  ventricle  even  after 
the  ventricle  had  been  slit  open.  But  in  subsequent 
experiments  upon  dogs,  we  ascertained  a  source  of 
fallacy  which  we  had  overlooked  in  the  other  expe- 
riment, for  we  found  that  a  slight  movement  of 
the  heart  on  the  surface  upon  which  it  rests,  such 
as  that  caused  by  a  very  gentle  pull  at  the  large 
arteries,  and  not  exceeding  the  effects  produced  by 
the  contraction  of  the  auricle,  was,  in  some  of 
these  cases,  sufficient  to  excite  contractions  of  the 
ventricles. 

}  In  one  experiment  upon  a  cat,  I  distinctly  ob- 
served the  right  ventricle  occasionally  pulsate 
twice  for  each  pulsation  of  the  auricle.  In  another 
experiment,  1  distinctly  observed  the  contractions 
of  the  ventricles  precede  those  of  the  auricles, 
when  the  contractility  of  the  heart  had  become  en- 
feebled. In  this  case,  the  pause  in  the  heart's 
action  occurred  after  the  contraction  of  the  auri- 
cles. 


contractions  of  the  ventricles  do  not  neces- 
sarily follow  those  of  the  auricles,  unless 
the  contractions  of  the  auricles  occasion  the 
application  of  a  stimulant  to  the  inner  sur- 
face of  the  ventricles  sufficient  to  excite  Ihem 
to  contraction.  4thly.  The  movements  of  the 
ventricles  and  auricles  will  go  on  in  the  same 
manner,  though  detached  from  each  other 
by  the  knife.  5thly.  If  we  were  allowed  to 
argue  from  final  causes  in  negative  cases,  we 
could  easily  shew  that  a  peculiar  endow- 
ment, such  as  we  are  contending  against, 
would  not  be  of  the  slightest  advantage  in  se- 
curing the  regularity  and  constancy  of  the 
heart's  movements.  It  appears,  then,  quite  un- 
philosophical  to  call  in  the  agency  of  some  un- 
known and  indefinite  principle  for  the  produc- 
tion of  these  periodic  movements,  as  they  have 
been  called,  of  the  different  chambers  of  the 
heart,  when  they  can  be  satisfactorily  referred 
to  the  laws  which  regulate  muscular  contracti- 
lity in  other  parts  of  the  body.  We  have  here 
a  beautiful  example  of  the  manner  in  which 
nature  produces  adaptation  of  means  to  an  end, 
not  by  the  creation  of  new  properties,  which 
we,  in  our  ignorance,  sometimes  erroneously 
attribute  to  her,  but  by  the  employment  of 
those  already  in  use  in  the  performance  of  other 
functions,  only  modified  to  accommodate  them 
to  the  circumstances  under  which  they  are 
placed. 

Sounds  of  the.  heart. — On  applying  the  ear 
over  the  region  of  the  heart,  two  distinct 
sounds  are  heard  accompanying  its  contraction. 
Though  the  existence  of  such  sounds  seems  to 
have  been  known  to  Harvey,*  who  compares 
them  to  the  noise  made  by  the  passage  of  fluids 
along  the  oesophagus  of  a  horse  when  drinking, 
yet,  as  is  well  known,  it  is  to  Laennec  that  we 
owe  the  first  accurate  description  of  the  charac- 
ter of  these  sounds,  the  order  of  their  succes- 
sion, and  the  manner  in  which  they  may  here- 
after be  made  available  for  the  important  pur- 
poses of  the  diagnosis  of  the  diseases  of  the 
heart. 

The  first  of  these  sounds  is  dull  and  pro- 
longed ;  the  second,  which  follows  closely  upon 
the  first,  is  sharp  and  quick,  and  is  likened  by 
Laennec  to  the  flapping  of  a  valve,  or  the  lap- 
ping of  a  dog.  After  the  second  sound  a  pause 
ensues,  at  the  end  of  which  the  sounds  are 
again  heard.  These  three — the  first  sound,  the 
second  sound,  and  the  pause — occur  in  the 
same  uniform  order,  and  when  included  along 
with  the  movements  of  the  heart,  to  which  they 
owe  their  origin,  have  received  the  term  rhythm 
of  the  heart.  As  the  dull  prolonged  sound  is 
synchronous  with  the  impulse  of  the  heart,  and 
consequently  with  the  contraction  of  its  ventri- 
cles, Laennec  attributed  this  sound  to  the  con- 
traction of  the  ventricles.  The  second  sound, 
which  is  synchronous  with  the  diastole  of  the 
ventricles,  he  supposed  must  depend  upon  the 
systole  of  the  auricles  ;  and  to  this  he  was 
naturally  led  by  the  supposition  that  their  con- 
traction must  also  produce  some  sound.  From 
the  weight  of  Laennec's  authority,  this  opinion 

*  Op.  cit.  cap.  v. 


HEART. 


615 


seems  to  have  been  almost  implicitly  adopted  un- 
til the  appearance  of  a  paper  by  the  late  Professor 
Turner,  in  1829.    Professor  Turner  there  re- 
called to  the  attention  of  medical  men  the 
observations  of  Harvey,  Lancisi,  Senac,  and 
Haller,  upon  the  order  of  succession  in  which 
the  cavities  of  the  heart  contract,  which  appear 
to  have  been  forgotten  amidst  admiration  at 
the  brilliancy  of  Laennec's  progress.    He  also 
pointed  out  from  their  experiments  that  if  the 
second  sound  was  dependent  upon  the  con- 
traction of  the  auricles,  it  ought  to  precede 
instead  of  following  the  first  sound,  and  that 
the  pause  ought  to  occur  after  the  first  sound, 
and  not  after  the  second.    He  also  adduced,  in 
farther  proof  of  Laennec's  error,  observations 
drawn  from  the  effects  of  disease,  when,  from 
some  impediment  to  the  passage  of  the  blood 
from  the  right  auricle  into  the  ventricle,  a  dis- 
tinct regurgitation  takes  place  into  the  large 
veins  at  the  root  of  the  neck,  and  showed  that 
in  these  cases  the  regurgitation  marking  the 
contraction  of  the  auricles  occurs  without  any 
accompanying  sound  ;  that  immediately  after- 
wards the  impulse  is  felt  attended  by  the  first 
sound,   and   that    the  second   sound  takes 
place    during  the  diastole  of  the  ventricles 
and  the  passive   condition   of  the  auricles. 
He  suggested  that  the  second  sound  might  be 
accounted  for  by  the  falling  back  of  the  heart 
into  the  pericardium  during  its  diastole,  to 
which  "the  elasticity  of  the  ventricles  at  the 
commencement  of  the  diastole,  attracting  the 
fluid  by  suction  from  their  corresponding  auri- 
cles, may  perhaps  contribute."    Soon  after  the 
appearance  of  Mr.  Turner's  paper,  Laennec's 
explanation  of  the  cause  of  the  second  sound 
appears  to  have  been  pretty  generally  aban- 
doned ;  and  numerous  attempts,  both  in  this 
country  and  in  France,  have  since  that  time 
been  made  to  solve  this  difficulty.    Some  of 
these  explanations  appear  to  be  mere  guesses, 
occasionally  at  total  variance  with  the  anato- 
mical structure  of  the  organ,  and  at  times  pre- 
senting even  as  wide  a  departure  from  its  nor- 
mal action  as  that  given  by  Laennec  himself. 
Others,  again,  have  entered  upon  an  experi- 
mental investigation  of  the  subject  with  en- 
lightened views  of  its  anatomy  and  physiology, 
have  furnished  us  with  much  additional  infor- 
mation, and  lead  us  to  indulge  in  the  pleasing 
prospect  that  in  a  short  time  the  matter  will  be 
completely  set  at  rest. 

The  result  of  the  experiments  of  Hope  and 
Williams,  attested  as  they  have  been  by  various 
gentlemen  well  qualified  to  judge  of  their 
accuracy, — also  those  of  Mr.Carlisle,  Magendie, 
Bouillaud,  and  the  Dublin  Committee,  have 
satisfactorily  determined  that  the  account  of  the 
order  of  the  contractions  of  the  heart,  and 
their  isochronism  to  the  sounds  as  stated  by 
Mr.  Turner,  are  perfectly  correct.  As,  how- 
ever, so  many  different  circumstances  attend 
each  movement  of  the  heart,  any  one  of  which 
may  be  capable  of  producing  these  sounds,  it 
became  a  much  more  difficult  matter,  and  one 
requiring  great  perseverance  and  accuracy  of 
investigation,  to  determine  upon  what  particular 
one  or  more  of  these,  each  sound  depends. 


For  accompanying,  and  synchronous  wtth  the 
first  sound,  we  have  the  contraction  of  the  ven- 
tricles, the  collision  of  the  different  currents  of 
blood  contained  there  thus  set  in  motion,  the 
approximating  of  the  auriculo-ventricular  valves, 
the  impulse  of  the  heart  against  the  chest,  and 
the  propulsion  of  the  blood  along  the  large 
arteries;  while  attending  the  second  sound,  we 
have  the  diastole  of  the  ventricles,  and  the  rush 
of  a  certain  quantity  of  blood  from  the  auricles 
into  the  ventricles,  the  sudden  separation  of 
the  auriculo-ventricular  valves  towards  the 
walls  of  the  ventricles,  and  the  regurgitation  of 
part  of  the  blood  in  the  arteries  upon  the  semi- 
lunar valves,  throwing  them  inwards  towards 
the  axes  of  the  vessels ;  so  we  will  find  that 
each  of  these  in  its  turn  has  been  thought  ca- 
pable of  producing  the  sound  which  it  accompa- 
nies, and  still  has,  or  until  lately  had,  its  advocates 
and  supporters.  As  the  subject  is  one  surrounded 
with  numerous  and  unusual  difficulties,  and  is  of 
comparatively  recent  investigation,  it  has  fol- 
lowed, as  was  to  be  anticipated,  that  as  new 
facts  and  observations  are  collected,  many  of 
the  opinions  first  promulgated  on  this  question 
have  required  to  be  modified  or  changed;  and 
the  scientific  candour  displayed  by  several  of 
these  authors  in  renouncing  former  published 
opinions  is  deserving  of  the  highest  praise. 

Several  of  the  explanations  of  the  cause  of 
the  sounds  of  the  heart  proceed,  however,  upon 
the  supposition  that  the  relation  of  these  sounds 
to  the  movements  of  the  organ  is  different 
from  what  has  been  here  represented.  We 
shall  merely  state  these  without  alluding  to  the 
arguments  adduced  in  support  of  them,  as  we 
believe  that  they  are  founded  upon  inaccurate 
observation.  Sir  D.  Barry  believed  that  the 
first  sound  was  synchronous  with  the  diastole 
of  the  auricles,  and  the  second  sound  with  the 
diastole  of  the  ventricles.  Mr.  Pigeaux,  Dr. 
Corrigan  also  until  lately,  Dr.  Stokes,  Mr. 
Hart,  and  Mr.  Beau,  have  maintained  that  the 
first  sound  is  synchronous  with  the  diastole, 
and  not  with  the  systole  of  the  ventricles.  Ac- 
cording to  Mr.  Pigeaux,  when  the  auricles 
contract  they  project  the  blood  against  the  walls 
of  the  ventricle,  and  a  dull  sound  (first  sound) 
is  produced  ;  on  the  other  hand,  whilst  the 
ventricles  contract,  they  project  the  blood 
against  the  thin  walls  of  the  great  vessels  which 
spring  from  them,  and  a  clear  sound  (second 
sound)  is  the  result.  Dr.  Corrigan  supposed 
that  the  first  sound  was  produced  by  the  rush 
of  blood  from  the  auricles  into  the  dilating 
ventricles,  and  that  the  second  sound  owed  its 
origin  to  the  striking  together  of  the  internal 
surfaces  of  the  ventricles  during  their  contrac- 
tion, after  they  had  expelled  all  their  blood. 
Mr.  Beau  believes  with  M.  Magendie  that  the 
first  sound  arises  from  the  impulse  of  the 
heart  against  the  inner  surface  of  the  chest,  but 
differs  from  him  in  maintaining  that  this  occurs 
during  its  diastole,  and  not  during  its  systole. 
The  second  sound  he  believes  to  depend  upon 
the  dilatation  of  the  auricles.  M.  Piorry  has 
revived  the  obsolete  and  perfectly  untenable 
opinion  of  Nicholl,  that  the  two  ventricles 
contract  at  different   times,   and  attributes 


616 


HEART. 


the  dull  sound  to  the  contraction  of  the  left 
ventricle,  and  the  clear  sound  to  the  contraction 
of  the  right  ventricle.  Dr.  David  Williams, 
while  he  believes  that  the  first  sound  depends 
upon  the  rush  of  blood  into  the  large  arteries 
during  the  systole  of  the  ventricles,  attributes 
the  second  sound  to  the  musculi  papillares, 
which  he  considers  as  forming  part  of  the  val- 
vular apparatus,  causing  the  valves  to  strike 
against  the  walls  of  the  ventricles.  These  mus- 
culi papillares  do  not,  in  his  opinion,  contract 
during  the  systole  of  the  ventricles,  but  imme- 
diately afterwards,  for  the  purpose  of  throwing 
open  the  auriculo-ventricular  valves.  In  a 
former  part  of  this  article  several  circum- 
stances are  stated  adverse  to  this  opinion. 

We  shall  now  proceed  to  the  explanation  of 
the  cause  of  these  sounds  given  by  those  who 
maintain  the  views  of  the  rhythm  of  the  heart 
which  we  have  here  adopted,  as  resting  upon 
the  concurrent  testimony  of  numerous  accurate 
observers.  These  may  be  divided  into  those 
who  attribute  both  sounds  to  causes  intrinsic  to 
the  organ,  or,  in  other  words,  to  circumstances 
occurring  within  the  organ  itself,  and  into  those 
who  place  them  external  to  the  organ,  and 
depending  upon  extraneous  objects.  The  only 
supporters  of  the  latter  opinion  are  Magendie 
and  his  followers.  Magendie  maintains  that 
"incontracting,andfor  causes  long  since  known, 
the  ventricles  throw  the  apex  of  the  heart 
against  the  left  lateral  part  of  the  thorax,  and 
thus  produce  the  first  sound,  i.  e.,  the  dull 
sound.  In  dilating,  in  a  great  measure  under 
the  influence  of  the  rapid  influx  of  the  blood, 
the  heart  gives  a  shock  to  the  anterior  paries 
on  the  right  of  the  thorax,  and  thus  produces 
the  second  sound,  the  clear  sound."  In  proof 
of  this,  he  states  that  on  removing  the  sternum 
of  a  swan  (an  animal  selected  expressly  for 
the  experiment,  as  it  interfered  less  with  the 
natural  action  of  the  heart  than  in  the  Mam- 
malia), he  found  that  the  movements  of  the 
heart  produced  no  sound,  while,  on  replacing 
the  sternum,  and  allowing  the  heart  to  impinge 
upon  its  posterior  surface  as  in  the  natural 
state,  both  sounds  were  again  distinctly  heard. 
He  adduces  several  arguments  drawn  from  the 
action  of  the  heart  both  in  its  healthy  and  dis- 
eased state  in  favour  of  his  opinion  ;  and  he 
ingeniously  attempts  to  get  rid  of  the  objection 
which  must  instantly  suggest  itself,  that  in 
many  cases,  such  as  frequently  occur  in  hyper- 
trophy of  the  organ,  the  loudness  of  the  sounds 
is  diminished,  while  the  force  of  the  impulse 
is  increased,  by  arguing  that  in  these  cases  this 
increased  impulse  depends  rather  upon  a 
heaving  of  the  chest  produced  by  the  heart, 
which  from  its  increased  size  is  brought  close 
to  its  inner  surface,  than  upon  a  distinct  im- 
pingement upon  it,  such  as  takes  place  in  the 
healthy  state.  Dr.  Hope,  M.  Bouillaud,  Dr.  C. 
J.  B.  Williams,  and  the  Dublin  and  London 
Heart  Cominitees  have,  however,  distinctly 
heard  both  sounds  of  the  heart,  after  that  por- 
tion of  the  chest  against  which  it  impinges  had 
been  removed.  It  may,  nevertheless,  be  objected 
to  these  experiments,  that  as  the  stethoscope  was 
used  in  many  of  them,  the  impulse  of  the  heart 


against  the  extremity  may  have  produced  an 
effect  similar  to  its  impulse  against  the  parietes 
of  the  thorax.  M.  Bouillaud,  having  appa- 
rently this  objection  in  view,  states  that  the 
rubbing  of  the  heart  during  its  movements 
against  the  extremity  of  the  stethoscope,  is 
easily  distinguished  from  the  sounds  of  the 
heart;  and  that  he  has  distinctly  heard  both 
sounds,  though  feebler  than  through  a  stetho- 
scope, as  was  to  be  expected  when  nothing  but 
a  cloth  was  interposed  between  his  naked  ear 
and  the  surface  of  the  heart.  Dr.  C.J.  B. 
Williams,  in  his  experiments,  heard  both  sounds 
when  the  stethoscope  was  placed  over  the  origin 
of  the  large  arteries,  and  where  no  external 
impulse  could  take  place  ;  and  this  observation 
was  repeated  by  the  Dublin  Committee.  The 
Dublin  Committee  heard  both  sounds  through 
the  stethoscope,  though  feebler  after  the  peri- 
cardium had  been  injected  with  tepid  water ; 
and  in  another  experiment  they  were  also 
heard  when  the  ear  was  simply  approximated 
to  the  organ.  From  all  these  experiments,  I 
think  there  can  be  little  doubt  that  the  move- 
ments of  the  heart,  independent  of  all  extra- 
neous circumstances,  are  attended  by  a  double 
sound.  As  the  impulse  of  the  heart  against 
the  chest  must  produce  some  sound,  as  any 
one  may  convince  himself  by  making  the  ex- 
periment in  the  dead  body,  and  as  this  occurs 
during  the  systole  of  the  heart,  or,  in  other 
words,  during  the  first  sound,  it  may  increase 
the  intensity  of  that  sound.  Dr.  R.  Spittal,* 
after  relating  several  experiments  in  which  a 
sound  similar  to  that  of  the  first  sound  of  the 
heart  was  heard  by  tapping  gently  with  the 
apex  of  the  heart  or  the  point  of  the  finger 
against  the  chest,  both  when  empty  and  when 
filled  with  water,  and  after  pointing  out  several 
sources  of  fallacy  which  he  supposes  were  not 
sufficiently  guarded  against  in  the  experiments 
which  we  have  adduced  above  as  subversive  of 
this  view,  and  which  deserve  the  attention  of 
future  experimenters,  comes  to  the  conclusion 
that  "  it  is  highly  probable  that  the  percussion 
of  the  heart  against  the  thoracic  parietes  during 
the  contraction  of  the  ventricles  assists  mate- 
rally  in  the  production  of  the  first  sound." 
He  is  also  inclined  to  believe  "  that  the  act  of 
the  separation  of  the  heart  from  the  thorax  after 
its  approach,  which  was  found  in  his  experiment 
to  produce  a  sharp,  short  sound,  somewhat 
resembling  the  ordinary  sound,  may  in  certain 
circumstances  be  an  assistant  cause  to  the 
second  sound. "f  Magendie's  explanation  of 
the  second  sound  is  completely  untenable. 

Among  those  who  maintain  that  these  sounds 
depend  upon  causes  intrinsic  to  the  heart,  the 
first  sound  is  referred  by  Rouanet,  Billing, 
Bryan,  and  Bouillaud  to  the  rapid  approxima- 
tion of  the  auriculo-ventricular  valves  during 
the  systole  of  the  ventricles,  to  which  Bouillaud 

*  Edin.  Med.  and  Surg.  Journal,  July  1836. 

t  Though  Dr.  Spittal  is  inclined  to  believe  that 
the  impulse  of  the  heart  against  the  chest  has  con- 
siderable share  in  the  production  of  the  first  sound, 
he  does  not  concur  with  Majendie  in  the  explana- 
tion of  the  second  sound. 


HEART. 


617 


adds  tho  sudden  separation  of  the  semilunar 
valves  when  the  blood  is  forced  into  the  large 
arteries ;  by  Mr.  Carlisle  to  the  rushing  of  the 
blood  along  the  inner  surface  of  the  large 
arteries  during  the  systole  of  the  ventricles.* 
Dr.  Hope,  in  the  appendix  to  the  second 
edition  of  his  work,  describes  it  as  consisting, 
1st,  possibly  of  a  degree  of  valvular  sound; 
2d,  of  a  loud  smart  sound  produced  by  the 
abstract  act  of  a  sudden  jerking  extension  of 
the  muscular  walls,  in  the  same  manner  that 
such  a  sound  is  produced  by  similar  extension 
of  the  leather  of  a  pair  of  bellows;  to  avoid 
circumlocution,  he  calls  it  the  sound  of  exten- 
sion ;  3d,  a  prolongation  and  possibly  an  aug- 
mentation of  this  sound  by  the  sonorous  vibra- 
tions peculiar  to  muscular  fibre."  Dr.  C.J.  B. 
Williams  has  very  justly  objected  to  the  correct- 
ness of  the  second  cause  here  adduced  as 
aiding  in  the  production  of  the  first  sound,  as 
the  phrase  "  sound  of  extension"  is  obviously 
contradictory  when  applied  to  a  contracting 
muscle.f  Dr.  C.  J.  B.  Williams  maintains 
"  that  the  first  sound  is  produced  by  the  mus- 
cular contraction  itself,"  the  clearness  of  which 
is  increased  by  the  quantity  of  blood  in  the 
heart  "  affording  an  object  around  which  the 
fibres  effectually  tighten,  whilst  the  auricular 
valve,  by  preventing  the  reflux  of  the  blood, 
increases  its  resistance,  and  thus  adds  to  the 
tension  necessary  for  its  expulsion."  He  was 
first  led  to  the  adoption  of  this  opinion  by  the 
observations  of  Enman  and  Wollaston  upon 
the  existence  of  a  sound  accompanying  every 
rapid  muscular  contraction.  This  opinion  he 
afterwards  put  to  the  test  of  experiment,  the 
results  of  which  we  give  in  his  own  words. 
"  Experiment  1st,  observation  8th;  I  pushed 
my  finger  through  the  mitral  orifice  into  the 
left  ventricle  and  pressed  on  the  right  so  as  to 
prevent  the  influx  of  blood  into  either  ventricle  ; 
the  ventricles  continued  to  contract  strongly 
(especially  when  irritated  by  the  nail  of  the 
finger  on  the  left),  and  the  first  sound  was  still 
distinct,  but  not  so  clear  as  when  the  ventricles 
contracted  on  their  blood.  Observation  9th. 
The  same  phenomena  were  observed  when  both 
the  arteries  were  severed  from  the  heart."  He 
also  found  in  other  observations  that  the  first 
sound  was  louder  over  the  surface  of  the  ven- 
tricles than  over  the  origin  of  the  large  arteries, 
which  is  in  direct  opposition  to  the  opinion  of 
those  who  believe  that  this  is  produced  by  the 
rush  of  blood  along  the  great  arteries.  That 
the  first  sound  is  not  dependent  upon  the  closing 
of  the  auriculo-ventricular  valves,  he  also 
ascertained  from  observations,  in  which  the 
closure  of  these  valves  was  partially  or  com- 
pletely prevented,  and  yet  the  first  sound  was 
still  heard.  Besides,  this  sound  continues 
during  the  whole  of  the  ventricular  systole, 
while  the  shutting  of  the  valves  must  take  place 
and  be  completed  at  the  commencement  of  the 
systole."    That  the  collision  of  the  particles  of 

As  Mr.  Carlisle  is  a  member  of  the  Dublin 
Heart  Committee,  we  must  now  consider  him  as 
concurring  with  the  report  of  that  Committee, 
t  Medical  Gazette,  Sept.  1835. 


fluid  in  the  ventricles  does  not  produce  this 
sound  he  was  convinced  from  observations,  in 
which  it  continued  although  there  was  no  blood 
in  the  ventricles. 

Though  we  must  admit  that  these  experi- 
ments of  Dr  Williams  prove  that  part  at  least 
of  the  first  sound  is  caused  by  the  muscular 
contraction  of  the  ventricles,  yet  we  must  con- 
sider it  still  problematical,  until  we  obtain 
further  observations,  whether  it  produces  the 
whole  of  that  sound,  for  it  is  very  possible  that 
some  of  the  other  circumstances  attending  the 
systole  of  the  heart  may  increase  its  intensity. 
M.  Marc  d'Espine  has  maintained  that  both 
sounds  depend  on  muscular  movements;  the 
first  sound  upon  the  systole,  and  the  second 
upon  the  diastole  of  the  ventricles.  The  Dub- 
lin Committee  have  in  the  meantime  concluded 
that  the  first  sound  is  produced  either  by  the 
rapid  passage  of  the  blood  over  the  irregular 
internal  surface  of  the  ventricles  on  its  way 
towards  the  mouths  of  the  arteries,  or  by  the 
bruit  musculaire  of  the  ventricles,  or  probably 
by  both  these  causes.  We  must  wait  for  further 
experiments  before  this  question  can  be  fairly 
settled  .* 

Second  sound. — Later  experimenters  appear 
to  be  more  nearly  agreed  about  the  cause  of 
the  second  sound  than  that  of  the  first  sound. 
M.  Rouanet  appears  to  have  been  the  first  who 
publicly  maintained  the  opinion  that  the  second 
sound  was  dependent  upon  the  shock  ot  blood 
against  the  semilunar  valves  at  the  origin  of 
the  aorta  and  pulmonary  artery.  M.  Rouanet 
himself  acknowledges  that  he  owed  the  sug- 
gestion to  Dr.  Carswell,  at  that  time  studying 
in  Paris,  who  came  to  that  conclusion  by  a 
beautiful  process  of  reasoning  upon  the  pheno- 
mena which  presented  themselves  in  a  case  of 
aneurism  of  the  aorta.  The  same  opinion  has 
been  supported  by  Billing,  Bryan,  Carlisle,  and 
Bouillaud.f    It  is,  however,  to  Dr.  C.  J.  B. 

*  The  London  Committee,  in  their  report  given 
in  at  the  meeting  of  the  British  Scientific  Associa- 
tion for  1836,  have  adduced  some  additional  expe- 
riments in  favour  of  the  opinion  that  the  first 
sound  of  the  heart  depends  upon  muscular  con- 
traction. It  appeared  to  them  that  the  sound  pro- 
duced by  the  contraclion  of  the  abdominal  muscles 
as  heard  through  a  flexible  tube  resembles  the 
systolic  sound.  They,  however,  admit  that  though 
"  the  impulse  is  not  the  principal  cause  of  the  first 
sound,  it  is  an  auxiliary  and  occasional  cause, 
nearly  null  in  quietude  and  in  the  supine  posture, 
but  increasing  very  considerably  the  sound  of  the 
systole  in  opposite  circumstances."  From  the  great 
care  with  which  these  experiments  appear  to  have 
been  performed,  we  believe  that  we  are  now  fullv 
justified  in  adopting  this  explanation  of  the  cause 
of  the  first  sound.  The  Dublin  Committee,  in  their 
report  given  in  at  the  same  time,  also  detail  some 
experiments  which  they  believe  to  be  confirmatory 
of  their  former  conclusions.  See  Sixth  Report  of 
British  Scientific  Association. 

t  In  justice  to  Dr.  Elliott,  of  Carlisle,  I  must 
state  that  I  find,  on  consulting  his  Thesis  De 
Cordc  Humano,  published  in  Edinburgh  in  1831, 
that  he  states  (p.  53)  that  he  believes  that  the 
second  sound  of  the  heart  is  dependent  upon  the 
rush  of  blood  from  the  auricles  into  the  ventricles 
during  their  diastole,  and  also  upon  the  sudden 
flapping  inward  of  the  sigmoid  valves  at  the  origin 
of  the  large  arteries  by  the  refluent  blood. 


618 


HEART. 


Williams  that  we  owe  the  first  direct  experi- 
ments in  support  of  it.  In  one  experiment  he 
ascertained  that  the  second  sound  was  louder 
over  the  origin  of  the  large  arteries  than  over 
the  surface  of  the  ventricles,  while  it  was  the 
reverse  with  the  first  sound;  that  pressure  upon 
the  origin  of  the  aorta  and  pulmonary  artery 
suspended  the  second  sound  ;  and  that  the 
second  sound  disappeared  after  the  auricles 
had  been  laid  open,  although  the  first  conti- 
nued. In  a  second  experiment*  we  find  the  fol- 
lowing observations  stated : — "  Observation  6. 
A  common  dissecting  hook  was  passed  into 
the  pulmonary  artery,  and  was  made  to  draw 
back  and  thus  prevent  the  closure  of  the  semi- 
lunar valves ;  the  second  sound  was  evidently 
weakened  and  a  hissing  murmur  accompanied 
it.  A  shoemaker's  curved  awl  was  then  passed 
into  the  aorta  so  as  to  act  in  the  same  way  on 
the  aortic  valves.  The  second  sound  now 
entirely  censed  and  was  replaced  by  a  hissing. 
Observation  7.  The  hook  and  the  awl  were 
withdrawn  ;  the  second  sound  returned  and  the 
hissing  ceased.  Observation  8.  The  experi- 
ment 6th  was  iepeated  with  the  same  result, 
and  whilst  Dr.  Hope  listened  I  withdrew  the 
awl  from  the  aorta.  He  immediately  said, 
'  Now  I  hear  the  second  sound.'  I  then 
removed  the  hook  from  the  pulmonary  artery  ; 
Dr.  Hope  said,  '  Now  the  second  sound  is 
stronger  and  the  murmur  has  ceased.'"  The 
Dublin  Committee  have  repeated  and  con- 
firmed these  experiments  of  Dr.  Williams.  In 
tlieir  experiments  one  of  the  valves  in  each 
artery  was  transfixed  and  confined  to  the  side 
of  the  vessel  by  a  needle,  and  the  second  sound 
disappeared  ;  on  withdrawing  the  needles  they 
re-appeared. 

As  the  second  sound  thus  appears  to  be  pro- 
duced by  the  shock  of  the  blood  upon  the  semi- 
lunar valves,  its  intensity  must,  in  a  great 
measure,  depend  upon  the  diastole  of  the  ven- 
tricle drawing  part  of  the  blood  back  upon 
them,  but  perhaps  more  particularly  upon  the 
elasticity  of  the  large  arteries  returning  suddenly 
upon  their  contents  during  the  diastole  of  the 
ventricles,  when  the  distending  force  of  the 
ventricles  has  been  withdrawn.  We  would 
therefore  expect  that  the  second  sound  should 
be  louder  in  those  whose  aorta  retains  its  elas- 
ticity, than  in  those  (a  circumstance  sufficiently 
common  in  old  age)  in  whom,  from  a  morbid 
alteration  of  the  structure  of  its  coats,  the 
elasticity  is  either  lost  or  greatly  diminished. 
This  is  an  observation  which,  as  far  as  I  know, 
has  not  yet  been  verified ;  but  my  friend  Dr. 
VV.  Henderson  informs  me  that  he  is  positive 
from  numerous  observations  that  the  second 
sound  is  louder  in  young  than  in  older  persons  ; 
but  whether  this  is  in  the  exact  ratio  of  the 
change  upon  the  elasticity  of  the  coats  of  the 
large  vessels  he  is  not  at  present  prepared  to 
say. 

*  These  experiments  were  performed  upon  asses, 
in  which  the  sensation  was  first  suspended  by  a 
dose  of  wourara  poison  and  then  maintaining  arti- 
ficial respiration.  In  this  manner  the  heart  con- 
tinued to  act  upwards  of  an  hour  after  the  com- 
mencement of  the  artificial  respiration. 


Bibliography.— as  a  complete  bibliography  of 
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include  all  the  systematic  works  on  Anatomy  and 
Physiology,  we  shall  here  confine  ourselves  to  the 
enumeration  of  those  works  and  memoirs  which 
treat  exclusively  or  in  a  prominent  manner  of  the 
normal  anatomy  or  functions  of  that  organ. 

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logie,  &c.  1823.  The  plates  given  by  Gerdy  in  the 
latter  work  have  been  copied  by  M.  Jules-Cloquet 
in  his  Planches  d'Anat.  de  l'Homme,  Sec.  torn.  iv. 
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mouvemens  du  coeur,  Liege,  1821. 

Memoirs  exclusively  on  the  relative  sixe  of  the  several 
cavities  of  tJie  heart. — Helvetius,  Sur  Pinegalite  de 
capacite  qui  se  trouve  entre  les  organs  destines  a 
la  circulation  du  sang  dans  le  corps  de  l'homme, 
&c.  Mem.  de  I'Acad.  de  Paris,  1718.  Weiss,  De 
dextro  cordis  ventriculo  post  mortem  ampliore, 
Altdorf,  1745.  Avrivillius,  De  cavit.  cordis  inaequali 
amplitudine,  &c.  Haller,  Disp.  Anat.  Sel.  vol. 
viii.  pars  ii.  p.  257.  1751.  Sabatier,  Mem.  de 
I'Acad.  de  Paris,  1774. 

Treatises  exclusively  on  the  nerves  of  the  heart. — 
Neubauer  (J.  E.),  Descriptio  nervorum  cardiaca- 
rum,  Frankfort  et  Leipsick,  1772.  Andersch,  De- 
script,  nerv.  cord,  in  torn.  ii.  Ludwig  Script. 
Neurol.  1792.  Behrends  (Jo.  B.  0.),  Dissertatio 
qua.  demonstratur  cor  nervis  carere,  Mayence, 
1792  ;  reprinted  in  torn.  iii.  Ludwig  Script.  Neu- 
rol, torn.  iii.  1793.  Zerenner,  An  cor  nervis  careat 
iisque  carere  possit  ?  Erford,  1794  ;  reprinted  in 


FIBRES  OF  THE  HEART. 


019 


torn.  iv.  LudVig.  Script.  Neurol.  1795.  Scarpa, 
Tabulae  Neurologicae,  &c.  Ticin.  17:J4. 

Memoirs  on  the  peculiarities  of  the  foetal  heart. — 
Memoirs  upon  the  Foramen  Ovale  by  Duverney, 
Mery,  Bussiere,  and  Littre  in  Mem.  de  1'Acad. 
1699  to  1703.  Winslow,  Sur  une  nouvelle  valvula 
de  Ja  venae  cavae  inferior,  qui  pent  avoir  rapport  a 
la  circulation  du  sang  dans  le  foetus  :  Mem.  de 
l'Acad.  1717.  Eclaircissement  sur  un  Mem.  de 
1717.  Ibid.  1725.  Haller  (Albert),  De  Valvula 
Eustachii,  G'dtting.  1737,  et  in  Disp.  Anat.  torn.  ii. 
1747.  Brendelius,  De  valvula  venae  cavae,  Wit- 
temberg,  1738  ;  reprinted  in  Opusc.  Math,  et  Med. 
Pars  i.  Lobstein  ( J.  F.),  DeiValvula  Eustachii, 
Strasbourgh,  1771.  Sabatier,  in  Mem.  de  l'Acad. 
1774.  Wolff,  De  foramine  ovali,  &c.  in  Nova 
Comment.  1'etropol.  t.  xx.  Kilian,  Kxeislauf  im 
Kinde,  &c.  Karlsruhe,  1826.  Biel  (Guil.),  De 
foraminis  ovalis  et  ductus  arteriosi  mutationibus, 
1827.  Berlin.  Jeffruy,  Peculiarities  of  the  foetal 
circulation,  Glasgow,  1834.  Edinb.  Med.  and  Surg. 
Journ. 1835. 

On  the  sounds  of  the  heart. — Laennec,  Traitc  de 
1' Auscultation  Mediate,  &c.  Paris,  1819.  Forbes's 
translation,  4th  edit.  1834.  Turner  (John  W. ), 
3  vol.  Med.-Chirurg.  Trans.  Edinb.  1828.  Wil- 
liams ( Dr.  David ),  Edinb.  Med.  and  Surg.  Journ. 
vol.  xxxii.  1829.  Corriyan,  Dublin  Med.  Transact, 
vol.  i.  1830.  Stokes  and  Hart,  Edin.  Med.  and 
Surg.  Journ.  1830.  Sjnttal  ( Dr.  R.J,  Treatise  on 
Auscultation,  Edinb.  1830.  Rouanet,  Journal  Heh- 
dom.  No.  97.  Pigeaux,  Journal  Hebdom.  torn.  iii. 
p.  239,  et  torn.  v.  p.  187,  for  1831,  et  Archiv. 
Gen.  do  Med.  Juillet  ct  Novembre,  1832.  Billing, 
Lancet,  May,  1832.  Hope,  A  Treatise  on  Dis- 
eases of  the  Heart  and  great  Bloodvessels,  1st  edit. 
1832.  Appendix  to  2d  edit.  1835.  Bryan,  Lancet, 
Sept.  1833.  Piorry,  Archiv.  Gen.  de  Med.  Juin, 
1834.  Newbiyginy  ( Dr.  P.  S.  K.J,  Inaugural  Dis- 
sertation on  the  impulse  and  sounds  of  the  heart, 
Edin.  1834.  Carlile,  Dublin  Journal  of  Medical 
Science,  vol.  iv.  1834,  and  Transact,  of  British 
Scient.  Assoc.  vol.  iii.  1834.  Mayendie,  Jjancet, 
Feb.  1835.  Medical  Gazette,  vol.  xiv.  Bouilland, 
Traite  clinique  des  maladies  du  coeur,  torn.  i.  1835. 
Williams  ( Dr.  C.  J.  B.J,  The  Pathology  and  Diag- 
nosis of  Diseases  of  the  Chest,  3d  edit.  1835,  and 
Medical  Gazette,  Sept.  1835.  Report  of  Dublin 
Committee  for  investigating  the  sounds  ' of  the 
Heart,  Dublin  Journal  of  Medical  and  Chemical 
Science,  Sept.  1835,  and  Transactions  of  British 
Scient.  Assoc.  vol.  v.  Beau,  Lancet,  Feb.  1836. 
Spittal  (Dr.  R.),  Edin.  Med  and  Surg.  Journal, 
July,  1836.  Reports  of  the  London  and  Dublin 
Committees  for  investigating  the  sounds  of  the 
heart.  Transactions  of  Biitish  Scientific  Asso- 
ciation, vol.  vi.  1837. 

( John  Reid.) 

ON  THE  ARRANGEMENT  OF  THE 
FIBRES  OF  THE  HEART— [The  Editor 
hopes  that  the  following  detailed  account  of 
the  researches  of  Mr.  Searle  on  this  difficult 
point  of  minute  anatomy  will  not  be  deemed 
unacceptable.  Any  reference  to  the  labours  of 
other  anatomists  has  been  rendered  unnecessary 
in  consequence  of  that  part  of  the  preceding 
article  which  bears  upon  this  subject.] 

Prcliminari/  remarks. — In  order  to  unravel 
the  fibres  composing  the  ventricles  of  the  heart, 
considerable  preparation  is  necessary.  The 
auricles,  fat,  coronary  vessels,  and  external  pro- 
per membrane  should  be  cleanly  dissected  off; 
the  heart  should  then  be  boiled  thoroughly,  but 
not  too  much,  so  as  to  give  its  fibres  the  requi- 
site degree  of  firmness  without  rendering  thern 
fragile.  For  example  :  sheep's  hearts  should 
be  boiled  ten  or  fifteen  minutes  ;  calves' twenty 


or  thirty,  and  bullocks'  forty  or  fifty  minutes ; 
immediately  afterwards  they  should  be  im- 
mersed in  cold  water  ;  for  if  they  be  exposed 
to  the  air  while  hot,  their  superficial  fibres  be- 
come dark,  dry,  and  brittle.  As  the  process  of 
unravelling  occupies  many  hours,  and  as  the 
heart  requires  to  be  preserved  in  a  good  condi- 
tion, it  should  be  immersed  during  the  intervals 
in  weak  spirit  and  water.  The  heart  of  the  calf 
is  preferable  to  that  of  any  other  animal,  it 
being  on  a  scale  which  affords  distinct  views, 
while  the  fibres  of  young  are  more  easily  sepa- 
rated than  those  of  older  animals.  The  con- 
formation is  the  same  in  all  quadrupeds,  and 
bears  a  complete  resemblance  to  that  of  the 
human  heart.  When  the  coronary  vessels  are 
dissected  off,  a  depressed  line  or  track  is  left  on 
the  anterior  and  posterior  surfaces  of  the  heart. 
Since  this  line  corresponds  externally  to  the 
entire  edge  of  the  septum,  and  to  the  boundary 
of  the  right  ventricle,  it  may  be  usefully  em- 
ployed in  reference  to  these  patts.  It  is  there- 
fore denominated  the  anterior  or  posterior  co- 
ronary track,  accordingly  as  it  pertains  to  the 
anterior  or  posterior  surface  of  the  heart. 

The  fibres  of  the  heart  are  not  connected 
together  by  cellular  tissue  as  are  those  of  other 
muscles,  but  by  an  interlacement  which  in 
some  parts  is  very  intricate,  and  in  others  scarcely 
perceptible.  At  the  entire  boundary  of  the  right 
ventricle  they  decussate,  and  become  greatly 
intermixed ;  at  the  apex  and  base  of  the  left 
ventricle  they  twist  sharply  round  each  other, 
and  so  become  strongly  embraced  ;  but  in  ge- 
neral the  interlacement  is  so  slight  that  they 
appear  to  run  in  parallel  lines.  Whether  a 
mere  fasciculus  or  a  considerable  mass  of  this 
last  description  of  fibres  be  split  in  the  direc- 
tion of  the  fibres,  a  number  of  delicate  parallel 
fibres  will  present  themselves,  some  being 
stretched  across  the  bottom  of  the  fissure  per- 
fectly clean  and  free  from  any  connecting  medium 
whatever;  and  although  some  must  necessarily 
be  broken,  yet  these  are  so  few  that  they  do  not 
attract  attention  unless  sought  for.  In  this 
process  of  separation  very  little  resistance  is 
offered  ;  and  none  that  is  appreciable  when  a 
single  fibril  is  taken  hold  of  by  the  forceps, 
and  stripped  off,  and  which  could  not  be  done  if 
bound  down  by  cellular  membrane. 

If  a  piece  of  common  muscle  be  afterwards 
split,  it  will  be  found  to  offer  great  resistance,  and 
to  be  attended  with  so  much  laceration  of  the 
fibres,  that  instead  of  a  beautiful  series  of  fine 
muscular  threads  arranged  in  parallel  lines, 
a  ragged  mass  of  mutilated  fibres  appears; 
and  during  the  process  of  separation,  the  cel- 
lular substance  is  seen  not  only  to  connect  the 
fibres,  but  to  afford  the  resistance  which  is  ex- 
perienced. 

This  comparison  obtains  in  the  undressed 
state  of  the  specimens ;  but  when  cooked, 
other  distinctions  are  met  with.  For  example  : 
in  whatever  direction  a  roasted  heart  be  sliced, 
its  cut  surface  is  uniformly  smooth,  not  grained 
like  other  muscles  when  dressed  ;  and  it  eats 
short,  not  offering  that  elastic  resistance  which 
other  muscles  do  during  mastication. 

The  absence  of  cellular  substance  as  a  con- 


620 


FIBRES  OF  THE  HEART. 
Fig.  278. 


CpcaaajvO 


Fie..  279. 


Fie.  280. 


Fig.  281. 


Cj?caa 


.Cacc 


Ca.cc 


Fig.  282. 


CRO 


necting  medium  among  the  fibres  in  question  mined  the  fibres  with  me,  could  detect  its  exist- 

is  not  only  proved  by  the  absence  of  its  physi-  ence.  ,.„.,.      „     „  ,  , 

cal  characters,  but  by  its  not  being  discovered        Since  the  chief  utility  of  cellu  ar  membrane 

through  the  medium  of  the  microscope.    Nei-  in  investing  and  connecting  together  the  fibres 

ther  Mr.  Kiernan  nor  Mr.  Goadby,  who  exa-  of  a  muscle  is,  most  probably,  that  ot  retaining 


FIBRES  OF  THE  HEART. 


621 


them  within  their  proper  spheres  of  action, 
and  since  the  fibres  of  the  heart  are  devoid  of 
this  agent,  the  question  arises  as  to  what  other 
retaining  power  these  possess.  On  this  head 
no  difficulty  presents  itself;  for  the  fibres,  in 
winding  round  and  round  the  cavity  of  the  left 
ventricle,  become  arranged  in  concentric  layers  ; 
and  in  taking  a  larger  sweep,  in  surrounding 
the  right  ventricle,  the  same  arrangement  is 
preserved,  so  that  during  the  systole  of  the 
heart  the  whole  mass  of  the  fibres  firmly  com- 
press each  other,  which  necessarily  retains  them 
all  within  their  proper  spheres  of  action,  ex- 
cepting the  superficial  fibres,  of  which  those 
towards  the  base,  and  especially  those  upon  the 
right  ventricle,  where  there  is  great  latitude  of 
motion,  do  not  preserve  a  parallelism  with  their 
subjacent  fibres,  but  lie  nearly  at  right  angles 
with  them.  It  is  on  this  account,  most  proba- 
bly, that  the  superficial  fibres  have  attracted 
notice,  and  have  been  viewed  as  a  distinct 
layer. 

The  disposition  of  the  fibres  varies  in  diffe- 
rent parts  of  the  heart,  forming  parallel  lines, 
angles,  decussations,  flat  and  spiral  twists.  The 
fibres  are  arranged  in  fasciculi,  bands,  layers, 
and  a  rope,  which  are  so  entwined  together  as 
to  form  the  two  chambers  called  the  right  and 
left  ventricles.  These  are  lined  with  their  in- 
ternal proper  membrane. 

The  fasciculi  are  connected  with  the  aorta, 
pulmonary  artery,  and  carnea?  columnar,  and 
contribute  to  the  formation  of  the  bands. 

The  bands. — By  tracing  the  fibres  in  bands, 
we  are  enabled  to  develop  the  formation  of  the 
ventricles  in  a  progressive  and  systematic  man- 
ner. The  bands  spring  from  a  mass  of  fibres 
which  forms  the  apicial  part  of  the  left  ventricle, 
and  which,  in  winding  round  just  above  the 
apex  of  the  heart,  separates  into  two  bands  to 
form  the  right  ventricle. 

It  will  render  the  demonstration  more  intel- 
ligible if  a  preliminary  and  cursory  view  be 
taken  of  the  general  course  of  these  bands 
(fig.  283,  p.  626,)  by  referring  to  the  diagram. 
The  bands,  as  there  given,  form  a  mere 
skeleton  of  the  heart,  merely  indicating  the  se- 
veral courses  they  take.  The  average  width  of 
the  bands  is  not  less  than  a  third  of  the  extent 
between  the  apex  and  base  of  the  left  ventricle. 
In  the  diagram,  crc  indicates  the  winding  of 
a  considerable  mass  of  fibres  just  above  the 
apex;  at  the  septum,  s,  it  splits  into  two  bands. 
The  shorter,  Cacc,  encircles  spirally  both 
ventricles,  one  half  round  the  right,  the  other 
round  the  left  ventricle.  The  longer  band  de- 
scribes two  circles :  it  first  passes  through 
the  septum,  round  the  left  ventricle  marked 
Cpca  ;  it  secondly  passes  round  the  base,  and 
includes  both  ventricles  in  its  circuit,  marked 
progressively  Cpcaa,  Cpcaaa,  CpcaaaaC,  and 

RE. 

After  employing  so  many  letters,  it  is  requi- 
site to  explain  that  as  the  bands  are  frequently 
receiving  fresh  accessions  of  fibres,  it  is  desira- 
ble to  characterise  those  increments  individually 
by  the  initials  of  the  names  of  the  respective 
sources  from  which  they  are  derived;  and  in 
order  to  make  a  distinction  between  the  indica- 


tions of  the  fibres  and  of  their  respective  origins, 
the  latter  are  characterised  by  double,  and  the 
former  by  single  initials.  Accordingly,  the 
aorta,  the  pulmonary  artery,  the  rope,  and  the 
carneae  columnar  are  designated  aa,  pp,  kr, 
and  cc,  while  their  fibres  are  marked  a,  p,  r, 
and  c.  This  plan  is  modified  in  one  instance 
only,  viz.,  the  fibres  of  the  main  bulk  of  the 
heart,  being  derived  from  the  rope  and  the  two 
carnea?  columnse  of  the  left  ventricle,  are  desig- 
nated in  the  first  instance  by  their  proper  ini- 
tials crc  ;  but  as  numerous  increments  of 
fibres  are  being  made,  in  succession,  to  these 
three  original  sets,  it  is  convenient  to  make  an 
abbreviation  in  the  lettering;  thus,  crc  is  in- 
dicated by  C  large,  when  combined  with 
other  initials ;  accordingly,  crca  is  con- 
tracted to  Ca,  and  crcpca  to  Cpca,  and  so 
with  the  rest. 

The  layers.- — Although  the  heart  admits  of 
being  split  into  a  number  of  layers,  yet  there 
being  no  material  division  formed  by  fasciae  or 
condensed  cellular  membrane,  such  separations 
are  strictly  arbitrary.  It  is,  however,  found 
convenient  to  separate  the  fibres  into  certain 
layers,  in  order  to  give  a  methodical  de- 
monstration of  the  formation  of  this  organ. 
The  same  remarks  obtain  regarding  the  bands. 

It  is  generally  supposed  that  the  superficial 
fibres  properly  constitute  a  distinct  layer,  form- 
ing a  common  sac,  which  encloses  the  two 
ventricles.  This  is  not  strictly  the  case,  for  it 
lias  the  same  origins  and  terminations  as  have  the 
fibres  immediately  subjacent  to  it.  Neverthe- 
less, the  superficial  fibres  are,  in  the  following 
description,  considered  as  a  separate  layer,  to 
show  the  peculiar  construction  of  the  apex. 

The  rope. — It  has  already  been  stated  that 
the  longer  of  the  two  bands  terminates  at  the 
base  in  the  rope.  The  fibres  of  this  band,  in 
forming  the  brim  of  the  left  ventricle,  make  a 
sharp  twist  like  those  of  a  rope,  by  which 
means  they  become  the  inner  fibres  of  this 
chamber,  and  expand  into  a  layer  which  enters 
largely  into  the  formation  of  the  mass  which 
divides  into  the  two  bands.  So  the  principal 
band,  although  it  receives  several  increments  of 
fibres,  has  no  complete  beginning  nor  ending, 
a  considerable  portion  of  it  originating  and  ter- 
minating in  itself,  which  circumstance  renders 
it  necessary  to  fix  upon  the  most  convenient 
part  of  its  course  for  the  commencement  of  the 
demonstration. 

Although  the  system  here  adopted  of  unra- 
velling the  fibres  of  the  heart  be  strictly  arbi- 
trary, as  every  other  must  be,  yet  it  will,  most 
probably,  be  found  the  only  method  by  which 
all  the  various  courses,  and  several  connexions 
made  by  the  fibres  in  forming  the  heart,  could 
be  displayed. 

The  demonstration. — It  is  requisite  to  pur- 
sue two  methods  of  demonstration  ; — one,  de- 
scribing the  dissection,  or  unfolding,  which 
consists  in  unravelling  and  separating  the  fibres, 
and  tracing,  from  the  circumference  to  the  cen- 
tre of  the  heart,  their  various  courses,  in  the 
form  of  bands,  by  which  they  become  in  order 
unwound,  and  by  which  a  general  view  of  the 
formation  of  the  two  ventricles  is  at  the 


6*22 


FIBRES  OF  THE  HEART. 


same  time  presented.  The  other,  describing 
the  formation,  or  winding  up  of  the  fibres, 
comprehends  the  retracing  of  the  fibres  from 
the  centre  to  the  circumference,  showing  their 
respective  origins,  associations,  courses,  con- 
nexions, and  terminations,  also  the  manner  in 
which  they  are  wound  up  to  form  the  two  ven- 
tricles into  one  compact  conical  body. 

The  dissection. —  The  first  stage  consists  in 
separating  the  superficial  fibres  from  the  two 
ventricles,  which,  perhaps,  cannot  be  accom- 
plished in  a  more  simple  manner  than  by  rais- 
ing them  in  the  forms  of  two  wings  and  a  tail, 
as  represented  in  fig.  279,  which  is  to  be  done 
by  commencing  at  the  anterior  coronary  track, 
cutting  through  the  superficial  fibres  and  de- 
taching them  by  means  of  a  blunt  scalpel  in 
their  natural  direction,  so  far  as  their  insertions 
at  the  base ;  this  will  be  found  to  divest  the 
right  ventricle,  and,  from  their  obliquity,  a  part 
of  the  left.  (See  the  left  wing,  Cacc)  Then 
recommencing  at  the  anterior  coronary  track, 
the  fibres  should  be  separated  in  the  contrary 
direction,  over  the  left  ventricle  towards  the 
apex.  These  fibres  take  a  very  6piral  course, 
and  as  they  approach  the  apex  converge,  but 
on  reaching  it  they  twist  sharply  round  upon 
themselves,  like  the  fibres  of  a  thick  cord,  and 
entering  at  the  apex  become  the  internal  fibres 
of  this  chamber.  The  remaining  part  of  the 
superficial  fibres,  extending  from  the  apex  to 
the  base,  pertains  exclusively  to  the  left  ventri- 
cle; these  should  be  divided  an  inch  or  two 
above  the  apex,  and  the  apicial  portion  detach- 
ed, which  will  complete  the  tail,  Crc.  Its 
fibres  are  represented,  as  they  appear  after  sepa- 
ration, untwisted.  The  basial  portion  of  these 
fibres  should  now  be  detached  so  far  as  the 
annulus  arteriosus,  and  reflected  like  the  right 
wing,  Crc.  These,  as  do  most  other  fibres 
which  approach  the  base,  take  a  more  longitu- 
dinal course,  and  in  general  they  become  so 
separated  as  they  diverge  to  encompass  the 
basial  part  of  the  heart,  that  they  cannot  be 
raised  in  an  entire  layer  unless  some  of  the 
subjacent  fibres  be  taken  with  them. 

The  second  stage  of  the  dissection  comprises 
the  disconnecting  the  bands  which  compose  the 
outer  or  proper  wall  of  the  right  ventricle. 
The  superficial  layer  of  fibres  having  been  re- 
moved, there  remain  two  other  layers  pertain- 
ing to  this  wall  of  the  ventricle,  viz.  the  middle 
and  the  internal.  The  middle  is  separable  into 
two  bands,  the  upper  or  basial,  and  the  lower 
or  apicial.  It  is  better  to  detach  the  apicial 
band  first,  which  makes  one  spiral  circle  round 
the  heart.  Its  outer  extremity  being  attached 
to  the  root  of  the  aorta  at  its  anterior  face,  and 
sometimes  to  the  pulmonary  artery  also,  an  in- 
cision should  be  made  extending  from  the  up- 
per part  of  the  anterior  coronary  track  obliquely 
towards  the  annulus  arteriosus,  which  incision 
should,  in  a  calf's  heart,  be  a  little  more  than 
an  inch  in  length  and  a  tenth  of  an  inch  in 
depth.  The  band  should  then  be  detached 
agreeably  to  its  spiral  course  from  the  base  and 
middle  third  of  the  left,  and  from  the  lower  half 
of  the  right  ventricle,  as  far  as  the  anterior  co- 
ronary track,  the  line  from  which  the  separation 


commenced.  It  here  receives  on  its  posterior 
surface  a  considerable  accession  of  fibres  from 
the  right  surface  of  the  septum,  by  the  junction 
of  which  this  part  of  the  boundary  of  the  ven- 
tricle is  formed,  but  the  further  separation  of 
the  band  prevented.  In  fig.  281,  in  the  first  or 
basial  part  of  its  course  it  is  indistinctly  seen, 
marked  Cacc  In  fig.  282  its  middle  course 
may  be  traced,  although  the  half  circle  of  the 
band  which  wound  round  the  left  ventricle  has 
been  cut  off.  In  the  preparation  exhibited  in 
this  figure  the  separation  of  this  band  could  not 
be  effected  under  the  posterior  coronary  track, 
on  account  of  the  separation  having  been  con- 
ducted too  deeply,  where  the  fibres  decussate 
to  form  the  posterior  boundary  of  the  right  ven- 
tricle. In  fig.  281,  which  exhibits  a  dissection 
of  the  right  ventricle  of  a  bullock's  heart,  the 
whole  of  the  band,  Cacc,  is  separated  as  far 
as  the  anterior  boundary  of  this  cavity,  and  lies 
extended ;  and  the  accession  of  fibres  it  re- 
ceives from  the  right  surface  of  the  septum  are 
seen  prolonged  into  it. 

The  basial  band  crosses  the  upper  half  of 
this  ventricle.  It  cannot  be  raised  from  its 
situation  on  account  of  the  numerous  lateral 
connexions  it  forms  in  its  progress  with  the 
margins  of  the  orifices  of  the  aorta,  pulmonary 
artery,  and  annulus  venosus.  In  order  to  de- 
tach it  as  far  as  it  will  admit,  an  incision  about 
half  an  inch  on  the  right  side  of  and  parallel 
with  the  anterior  coronary  track,  should  be 
made,  extending  from  its  lower  edge  to  the 
base,  and  an  eighth  of  an  inch  in  depth,  or  as 
deep  as  will  expose  the  fibres  from  the  pulmo- 
nary artery,  which  in  general  pass  at  an  angle 
with  those  of  the  band.  Although  this  band 
cannot  be  disconnected  from  the  base,  it  can  in 
general  be  detached  from  the  fibres  of  the  sub- 
jacent layer,  so  far  as  the  posterior  coronary 
track;  sometimes,  however,  they  are  too  inter- 
woven to  admit  of  any  separation.  The  first 
part  of  this  band  is  represented  in  fig.  281, 
marked  Cpcaa;  it  was  divided  more  than 
half  an  inch  from  the  anterior  coronary  track. 
Its  continuation  may  be  seen  in  fig.  2B2,  lettered 
Cpcaaa,  where  it  is  evidently  not  discon- 
nected from,  but  merely  raised  towards 
the  base,  and  if  replaced  would  overlap  the 
fibres  taking  the  middle  course  round  the  heart. 
The  depression  at  the  line  of  the  posterior  coro- 
nary track,  pet,  is  occasioned  by  the  band  being 
bound  down  at  the  base  and  at  its  under  sur- 
face also,  by  which  means  the  upper  half  of  the 
posterior  boundary  of  this  ventricle  is  formed. 
As  the  further  pursuit  of  this  band  pertains  to 
the  third  stage,  it  will  be  made  hereafter. 

The  internal  layer.  By  the  separation  of 
the  two  former  bands  the  internal  layer  is  ex- 
posed. It  is  composed  of  fibres  from  the  pul- 
monary artery  and  from  one  of  the  carneaj  co- 
lumnae.  In  fig.  281  the  fibres,  pc,  are  seen 
arising  from  the  root  of  the  pulmonary  artery  at 
its  entire  circumference,  first  forming  a  channel 
and  then  expanding  into  a  layer,  which,  in  pro- 
ceeding obliquely  across  the  cavity,  obtains  an 
accession  of  fibres  from  one  of  the  carneaj  co- 
lumna;,  which  is  not  brought  into  view,  and 
which,  on  reaching  the  line  of  the  posterior 


FIBRES  OF  THE  HEART. 


623 


coronary  track,  joins  a  band  emerging  from  the 
septum,  and  tnus  forms  the  apicial  half  of  the 
posterior  boundary  of  this  ventricle.  It  is 
raised  from  its  situation,  but  when  replaced  its 
edge,  which  is  everted  by  the  probe,  appl.es 
itself  to  the  anterior  boundary  of  this  cavity. 
This  layer  cannot  often  be  so  extensively  dis- 
connected from  its  superjacent  bands  as  this 
figure  represents. 

The  third  stage  of  the  dissection. — Having 
separated  the  layers  composing  the  right  or 
proper  wall  of  the  right  ventricle,  the  next  pro- 
ceeding consists  in  detaching  and  unwinding 
the  band  and  layers  composing  the  left  ventri- 
cle. First,  the  detachment  of  the  basial  band. 
As  this  band  has  already  been  detached  over 
the  right  ventricle  in  the  second  stage  of  the 
dissection,  it  is  necessary  to  resume  its  separa- 
tion at  the  posterior  coronary  track.  But  as 
the  further  separation  is  somewhat  difficult,  it 
will  be  rendered  less  so  if  the  remaining  portion 
of  this  band  be  first  examined  in  fig.  282, 
wherein  it  is  represented  detached.  When  in 
its  natural  situation  it  forms  the  uppermost 
third  of  this,  the  left  ventricle,  and  its  lower 
fibres  overlap  a  part  of  those  which  occupy  the 
middle  third.  The  fibres  which  overlap  the 
others  in  taking  an  oblique  course  towards  the 
base  reach  the  brim  of  the  ventricle  and  pass 
over  it,  while  the  under  fibres  of  this  band  are 
appearing  in  succession,  and  taking  a  similar 
spiral  course  until  the  whole  bundle  of  fibres  is 
twisted  in  the  form  of  a  rope.  In  order,  there- 
fore,to  trace  ou  t  and  detach  this  band  as  it  becomes 
transformed  into  a  rope,  it  is  requisite  to  com- 
mence near  the  posterior  coronary  track  (pet ), 
in  a  continuous  line  with  the  lower  edge  of  its 
former  portion,  introducing  the  handle  of  a 
scalpel  obliquely  upwards  so  as  to  detach  the 
fibres  which  overlap  those  of  the  middle  third, 
and  to  carry  the  separation  so  far  up  as  will 
reach  those  marked  a,  coming  obliquely  down 
from  the  aorta.  In  conducting  this  separation 
from  left  to  right  it  is  soon  found  that  the  fibres 
of  this  bundle,  instead  of  overlapping  others, 
become  themselves  by  twisting  overlapped, 
rendering  it  necessary,  therefore,  to  turn  gra- 
dually the  handle  of  the  scalpel  obliquely 
downwards,  tracing  the  rope  according  to  its 
windings.  Two  scalpels  will  be  required  in 
conducting  the  further  separation. 

The  next  step  should  be  preceded  by  viewing 
the  fibres  of  the  rope  in  fig.  280,  descending 
and  radiating  into  a  layer  which  sweeps  round 
the  cavity  of  this  ventricle.  The  heart  should 
now  be  placed  in  a  small  cup  or  jar  of  a  size 
that  will  support  it  with  its  base  upwards,  and 
then,  with  the  scalpels  employed  vertically,  the 
separation  should  be  proceeded  with,  and  in 
passing  through  the  septum  a  vertical  section 
should  be  made  through  the  aorta  in  the 
line  of  separation,  which  should  be  pursued 
round  and  round,  and  progressively  deeper 
until  the  handles  of  the  scalpels  perforate  the 
external  fibres,  which,  if  they  have  been  rightly 
inclined,  they  will  do  a  little  above  the  apex  of 
the  left  ventricle,  just  after  they  have  completed 
the  division  through  the  layers  of  the  septum. 
The  band  of  fibres  occupying  the  middle  third 


of  the  heart,  and  which  now  pass  over  the  scal- 
pels, should  be  divided;  the  incision  being 
made  along  the  side  of  the  posterior  edge  of 
the  septum.  A  section  should  be  made  through 
the  rope  also,  which  allows  the  right  ventricle 
to  be  raised  from  the  left,  and  the  heart  to  be 
unwound  as  far  as  the  separation  has  been  car- 
ried. There  yet  remains  a  mass  of  fibres 
around  the  cavity  of  the  left  ventricle  to  be  de- 
tached. This  last  process  of  separation  should 
be  conducted  in  a  contrary  direction  to  that 
which  has  hitherto  been  adopted,  viz.  from  right 
to  left,  until  the  internal  membranous  lining  is 
exposed,  and  which  should  be  torn  in  order  to 
lay  open  this  chamber. 

The  heart  can  now  be  unwound  and  extended 
as  in  fig.  278,  placing  the  left  ventricle,  Iv,  at 
one  end  and  the  right  at  the  other,  removing 
that  section  of  the  aorta,  aa,  connected  to  the 
right  ventricle  from  its  counterpart  which  ex- 
clusively pertains  to  the  left,  and  which  is  hid- 
den by  the  rope,  rr  ;  removing  also  the  two 
portions  of  the  bisected  rope  to  the  two  most 
distant  diagonal  points  in  this  view.  The 
niche,  Cpc,  indicates  the  part  occupied  by 
the  divided  band  which  passed  along  the  mid- 
dle third  of  the  heart. 

The  second  method  of  demonstration. — The 
formation,  or  winding  up  of  the  fibres, 
of  the  heart.  This  description  comprehends 
the  retracing  of  the  fibres  from  the  centre  to 
the  circumference,  showing  their  respective 
origins,  associations,  courses,  connexions,  and 
terminations,  also  the  manner  in  which  they 
are  wound  up  to  form  the  two  ventricles  into 
one  compact  conical  body. 

The  first  stage  consists  in  retracing  the  su- 
perficial layer  from  its  origins  to  its  termina- 
tions. It  is  necessary  to  commence  at  the 
very  centre  of  the  heart — the  interior  of  the  left 
ventricle,  whence  spring  the  fibres  composing 
its  main  bulk.  Fig.  278,  at  its  right  extremity, 
exhibits  the  left  ventricle,  Lv,  laid  open,  exposing 
the  two  carneae  columnar,  cc  and  cc,  one  of 
which  is  placed  out  of  its  situation,  in  order  to 
show  the  interior  of  the  chamber.  The  fibres 
of  the  two  carneae  columns,  cc  and  cc,  ex- 
pand in  a  fan-like  manner  ;  those  of  the  rope, 
rr,  expand  in  a  similar  manner ;  the  radiated 
fibres  of  each  of  these  three  bodies  wind  round 
the  axis  of  this  ventricle  forming  its  parietes  ; 
and  as  they  wind  so  as  to  form  an  inverted 
cone,  it  is  clear  that  the  inmost  fibres  alone 
can  reach  the  apex.  Accordingly,  a  fasciculus 
of  the  inmost  fibres  from  each  of  these  three 
bodies,  marked  c,  R,  and  c  respectively,  pass 
down  to  the  apex  associated  together,  and  in 
their  course  make  a  gentle  twist  from  left  to 
right,  gradually  contracting  the  cavity  to  a 
point  and  closing  it ;  they  then  twist  sharply 
round  upon  each  other  and  complete  the  apex 
marked  cite  conjoint!  i/,  so  that  by  means  of 
this  twisting  the  internal  fibres  are  rendered 
external.  These  excluded  fibres  now  enter  into 
the  formation  of  the  superficial  layer,  and  form 
the  tail  of  fig.  279.  They  take  a  very  spiral 
course  near  the  apicial  part,  and  over  the  an- 
terior surface  of  the  left  ventricle  as  far  as  the 
anterior  coronary  track ;  but  as  they  approach 


624 


FIBRES  OF  THE  HEART. 


the  base,  pass  more  longitudinally.  It  is  evi- 
dent that  these  few  fibres  would  be  inadequate 
to  form  a  complete  layer,  unless  in  their  pro- 
longation they  pursued  an  uniformly  spiral 
course.  They  are  more  than  enough  to  cover 
the  apicial  part  as  they  twist  over  each  other; 
but  in  consequence  of  the  conical  form  of  the 
heart  they  soon  become  singly  arranged,  and 
as  they  diverge,  separate  and  leave  interspaces, 
some  of  which  are  occupied  by  fibres  which 
apparently  arise  abruptly  at  the  surface.  The 
fibres  which  pass  longitudinally  to  the  base  of 
the  left  ventricle  are  inserted  into  the  tendinous 
margin  of  the  annulus  arteriosus,  and  into  the 
posterior  part  of  the  root  of  the  aorta,  forming 
the  right  wing,  crc.  The  spiral  fibres  have 
been  stated  to  arrive  at  the  anterior  coronary 
track  along  its  whole  length.  The  majority  of 
them  terminate  at  the  coronary  vessels  ;  others 
are  merely  intersected  by  them,  while  others 
pass  under  these  vessels  and  become  super- 
ficial again  :  those  which  maintain  their  course 
over  the  right  ventricle  vary  in  different  hearts 
from  a  small  to  a  considerable  number.  Along 
the  whole  length  of  this  track  accessory  fibres 
from  the  interior  of  the  right  ventricle  are 
emerging  to  associate  with  these  in  their  way 
over  this  ventricle.  They  take  a  longitudinal 
course  to  the  base,  and  therefore  start  at  an 
angle  with  the  spiral  fibres  which  are  on  the 
left  side  of  the  coronary  track.  In  fig.  281 
these  accessory  fibres  from  the  aorta,  a  a,  and 
from  two  of  the  carnes  columns,  are  seen 
passing  together  obliquely  down  the  right  sur- 
face of  the  septum,  marked  acc,  to  enter 
into  the  formation  of  the  extended  band. 
These  accessory  fibres  perforate  it  along  the 
anterior  boundary,  ab,  and  become  super- 
ficial. This  layer  is,  accordingly,  in  jig.  279, 
marked  Cacc;  its  fibres  pass  at  nearly  right 
angles  with  the  subjacent  fibres,  and  when 
raised  form  the  left  wing;  its  insertions  are 
the  anterior  part  of  the  root  of  the  aorta,  the 
tendinous  margin  of  the  annulus  venosus,  and 
again  the  right  part  of  the  root  of  the  aorta. 
Sometimes  festoons  are  formed  at  the  base  by 
communications  of  fibres  between  the  pulmo- 
nary artery  and  the  aorta,  at  its  right  and  pos- 
terior aspects. 

It  occasionally  happens  that  the  accessory 
fibres  which  arise  from  the  interior  of  the  right 
ventricle  are  not  very  numerous;  in  such  cases 
a  greater  number  of  fibres  arise  abruptly  from 
its  surface. 

The  superficial  layer  has  three  sets  of  ori- 
gins: one,  primitive,  from  the  interior  of  the 
left  ventricle;  the  others,  accessory,  from  the 
interior  of  the  right  ventricle,  and  from  the 
outer  surface  of  both.  It  cannot  with  pro- 
priety be  considered  as  one  common  invest- 
ment, since  each  ventricle  for  the  most  part 
gives  birth  to  its  own  superficial  fibres.  It  is 
necessary  to  raise  it  as  a  distinct  layer  for  two 
reasons  :  first,  that  the  superficial  fibres  of 
the  right  ventricle  in  general  pass  nearly  at  right 
angles  with  their  subjacent  fibres,  and  there- 
fore require  to  be  removed  in  order  to  proceed 
with  the  next  stage  of  separation :  secondly, 
that  it  developes  the  peculiar  mode  of  closing 


the  left  ventricle,  and  of  forming  the  apex ; 
and  probably  no  other  method  than  that  of  the 
twisting  of  the  fibres  could  have  been  so  secure, 
especially  as  the  parietes  at  the  apex  of  the 
ventiicle  do  not  generally,  even  in  a  bullock's 
heart,  exceed  a  tenth  of  an  inch  in  thickness. 

The  secund  stage  — The  external  layer  having 
been  traced  from  its  origins  to  its  insertions, 
we  may  now  trace  the  deep-seated  layers ;  and 
as  these  have,  for  the  most  part,  the  same 
origins,  courses,  and  insertions  as  the  super- 
ficial layer,  we  may  commence  the  description 
at  the  same  points. 

It  has  been  already  stated  that  the  fibres  of 
the  rope  and  of  the  two  earner  columns  ex- 
pand in  a  fan-like  manner,  that  their  inmost 
fibres  pass  through  the  apex  and  become  ex- 
ternal, but  that  the  chief  of  them  wind  round 
the  axis  of  the  left  ventricle  above  the  apex, 
as  exemplified  in  fig.  279,  crc.  The  respec- 
tive sets  of  fibres  pertaining  to  these  three 
bodies  continue  separate  during  their  radiation 
only,  after  which  they  become  plaited  together 
by  folding  one  over  the  others.  Their  mode 
of  association  is  shown  in  the  extended  portion 
of  the  split  layer,  crc  in  fig.  280,  also  in 
its  counterpart,  crc,  winding  round  the  api- 
cial part  of  the  ventricle.  Again,  in  fig.  278, 
it  may  be  seen  that  the  fibres  at  the  bases  of 
these  columns  turn  under  and  pass  up  in  con- 
junction with  those  of  the  rope  forming  the 
middle  mass,  cue,  at  the  upper  of  which 
they  fold  over  making  flat  twists  upon  them- 
selves, which  have,  however,  become  exag- 
gerated in  appearance  by  the  unwinding  of  the 
heart,  as  in  rolling  it  up  again  some  of  the 
angles  are  converted  into  spires,  preserving  a 
considerable  degree  of  parallelism. 

Having  shown  the  origins,  and  the  method 
adopted  in  the  association,  of  the  fibres  form- 
ing the  middle  mass  in  jig.  278,  we  proceed  by 
tracing  the  divisions  and  prolongations  of  its 
fibres,  and  the  plan  of  building  up  the  two 
chambers  of  the  heart.  First,  the  forma- 
tion of  the  left  ventricle.  If  the  right  carnea 
columna,  cc,  be  replaced  in  contact  with  its 
fellow,  and  if  the  rope,  rr,  be  brought 
round  the  upper  part  of  this  cavity  so  as  to 
embrace  them,  and  if  portion  4  be  split  from 
the  middle  mass,  crc,  and  be  wound,  in 
association  with  the  apicial  fibres,  crc,  round 
the  lower  part  of  this  cavity,  that  division  of 
the  heart,  comprising  the  left  ventricle  and  the 
middle  mass,  will  bear  a  near  resemblance  to 
that  represented  in  fig.  280 ;  in  which  figure 
the  rope,  rr,  in  embracing  the  heads  of  the 
carnes  columns,  cc,  brings  into  view  its  fan- 
like fibres,  r,  sweeping  round  the  upper  part 
of  the  axis  of  this  ventricle ;  in  which  the 
fibres  of  portion  4,  in  winding  round  the  lower 
half  of  the  axis,  embrace  the  bodies  of  the 
carnea;  columns,  cc,  and  associate  with  the 
apicial  fibres,  crc,  and  in  which  the  ex- 
tended layer,  cue,  represents  the  middle  mass 
minus  the  portion  4,  which  is  split  from  it. 
Thus  much  pertains  exclusively  to  the  descrip- 
tion of  the  formation  of  the  left  ventricle. 
That  of  the  right  is  more  complicated,  and 
constitutes — 


FIBRES  OF  THE  HEART. 


625 


The  third  stage.  In  pursuing  the  mass  of 
blended  fibres,  crc,  occupying  the  middle 
of  fig.  278,  it  is  found  that,  after  having  formed 
the  left,  it  splits  under  the  line  marked  by 
stars  into  two  bands,  which  embrace  and  con- 
tribute to  form  the  right  ventricle.  These  sepa- 
rated bands  were  stated  in  the  preliminary 
remarks  to  be  of  unequal  lengths,  the  longer 
making  two  and  the  shorter  making  but  one 
spiral  circle  round  the  heart.  The  longer,  in 
the  first  place,  assumes  the  character  of  a  layer 
and  forms  the  middle  layer  of  the  septum. 
It  requires  to  be  described  in  three  portions. 
Portion  1,  being  attached  to  the  valve  of  the 
other  section  of  the  aorta,  was  stripped  off  in 
unwinding  the  heart ;  in  the  wound-up  state  it 
passes  over  the  pulmonary  channel  of  fibres,  p, 
along  the  part  marked  1,  in  its  way  to  the 
aorta,  a  a  ;  its  absence,  however,  opens  to 
view  the  fibres  coming  from  the  base  and  form- 
ing the  right  layer  of  the  septum.  Portion  2 
proceeds  from  the  starred  line  across  to  enter 
into  the  formation  of  the  rope,  Rit,  and  will 
be  noticed  hereafter.  Portion  3  is  the  longer 
band;  it  is  not  entirely  seen,  being  overlapped 
by  some  of  the  fibres  of  portion  4 ;  it  passes 
across  to  the  niche,  Cpc,  where  it  was  di- 
vided in  unwinding  the  heart,  in  order  to 
liberate  the  two  ventricles  which  were  encircled 
together  by  this  band.  Previously  to  pursuing 
this  band  further,  it  is  better  to  trace  it  as  the 
middle  layer  of  the  septum  in  its  natural  situ- 
ation— the  wound-up  state  of  the  heart.  In 
fig.  280  it  forms  the  extended  layer,  crc,  in 
association  with  portion  2,  and  split  from  por- 
tion 4,  which  does  not  belong  to  the  septum  ; 
on  being  replaced,  its  cut  edge,  a,  applies  to 
the  cut  edge,  b,  in  passing  as  the  middle  layer 
between  the  right  and  left  layers  of  the  septum. 
The  middle  layer  is  seen  in  fig.  282  emerging 
at  the  posterior  edge  of  the  septum,  where 
portion  2  disconnects  itself  to  join  at  the  under 
surface  the  band  above,  but  in  this  figure  is 
marked  C  large,  indicating  that  it  is  derived 
from  this  layer,  which  has  hitherto  been  lettered 
crc.  This  layer,  being  now  deprived  of  all 
its  other  portions,  will  hereafter  be  considered 
as  a  band,  and  it  has  already  been  explained 
why  it  should  be  denominated  the  longer  band. 
This  band  in  emerging  at  the  posterior  edge  of 
the  septum  is  joined  by  another  band  of  fibres, 
which  is  seen  in  fig.  281,  forming  part  of  the 
internal  layer  of  the  proper  wall  of  the  right 
ventricle;  its  fibres,  pc,  arise  from  the  pul- 
monary artery,  pp,  and  from  one  of  the 
carneae  columnae  not  in  sight ;  they  cross  ob- 
liquely over  this  cavity  to  the  posterior  edge 
of  the  septum  to  join  the  band  in  ques- 
tion. By  the  intimate  blending  of  the 
fibres  of  these  two  bands  the  apicial  half 
of  the  posterior  boundary  of  this  ventricle  is 
constructed.  The  longer  band,  now  aug- 
mented, is  lettered  accordingly  in  fig.  282, 
Cpc,  and  in  proceeding  soon  receives  at  its 
inner  surface  an  accession  of  fibres,  a,  coming 
down  from  the  aorta.  This  band,  Cpca,  in 
winding  spirally  from  left  to  right  round  the 
left  ventricle  along  its  middle  third,  gradually 
approaches  both  the  base  and  the  surface  :  for 

VOL. II. 


when  it  arrives  at  the  anterior  edge  of  the  sep- 
tum it  becomes  the  basial  band,  and  having 
been  traced  round  the  left  under  the  right  ven- 
tricle, in  making  its  second  circle  it  passes  over 
that  cavity.  Injig.  281  the  commencement  of 
its  second  course  is  exhibited.  It  is  bisected, 
one  portion,  Cpcaa,  being  held  up  by  a 
probe  ;  the  other,  at  the  anterior  coronary  track, 
act,  receives  at  its  inner  surface  a  fasciculus 
of  fibres,  a,  from  the  aorta,  aa,  and  is  also 
lettered  Cpcaa.  This  fasciculus  and  por- 
tion of  the  band  form  together  a  groove,  by 
winding  over  the  pulmonary  channel  when 
brought  down  into  its  place,  and  which  toge- 
ther form  the  basial  part  of  the  anterior  boun- 
dary of  this  cavity.  This  band  in  its  progress 
round  this  ventricle  constitutes  the  basial  band 
of  the  middle  layer  of  its  proper  wall,  and 
forms  so  many  connexions  with  the  base,  that 
to  trace  them  all  would  be  found  a  very  com- 
plicated piece  of  dissection ;  it  is,  therefore, 
deemed  better  to  give  a  general  description  of 
them.  For  instance,  the  aorta  presents  three 
different  aspects  under  -which  this  band  is  con- 
nected to  it:  the  first,  at  the  termination  of  the 
anterior  coronary  track  ;  the  second,  between 
the  pulmonary  artery  and  the  annulus  venosus  ; 
and  the  third,  between  the  annulus  venosus  and 
the  annulus  arteriosus,  or  at  the  extremity  of 
the  posterior  coronary  track.  The  aorta  re- 
ceives at  each  of  these  parts  an  insertion  of 
fibres  from  the  outer  surface  of  the  band  ;  and 
the  band  receives  on  its  inner  surface  a  fasci- 
culus from  the  aorta.  These  reciprocal  com- 
munications occasion  the  band  to  be  very  firmly 
bound  down  to  the  base,  and  to  be  arranged, 
to  a  certain  extent,  into  festoons.  For  each 
of  these  accessions  from  the  aorta,  an  addi- 
tional a  is  added  to  the  lettering  of  the  band, 
which  is,  accordingly,  designated  Cpca  a  a  a. 
As  the  band  passes  the  annulus  venosus,  its 
outer  fibres  by  a  gentle  obliquity  in  their  course 
successively  arrive  at  its  tendinous  margin, 
into  which  they  become  inserted  immediately 
below  those  of  the  superficial  layer,  and 
some  proceeding  still  more  deeply  pass 
under  the  tendinous  margin  into  the  ven- 
tricle, and  form  the  musculi  pectinati. 
In  order  to  avoid  repetition  it  may  be  here 
remarked,  that  this  part  of  the  description  ap- 
plies to  the  annulus  arteriosus  also.  The  last 
two  accessions  of  fibres  this  band  receives 
should  be  traced,  since  they  assist  in  the  con- 
struction of  the  posterior  boundary  of  the  right 
ventricle.  In  fig.  282  this  band  is  seen  in  the 
latter  part  of  its  course  round  the  right  ventri- 
cle, marked  Citaaa;  on  reaching  the  pos- 
terior coronary  track,  pet,  it  is  joined  on  its 
inner  surface  by  two  fasciculi  which  bind  it 
down  to  the  base,  but  on  each  side  of  this 
track  it  is  separated  and  raised.  One  of  these 
fasciculi,  the  last  derived  from  the  aorta,  is 
not  seen  in  this  figure ;  the  other  appears  emer- 
ging from  under  this  ventricle,  being  portion  2 
of  the  middle  layer  of  the  septum,  which 
disconnected  itself  from  this  band,  Cpc,  in 
its  first  circle  round  the  left  ventricle  ;  it  is 
marked  C  large,  being  derived  from  the  middle 
mass  of  fibres,  cue,  in  fig.  278,   in  which 

2  T 


62G 


FIBRES  OF  THE  HEART. 


portion  2  is  seen  crossing  over  to  join  the  band 
CpcaaaaC,  just  before  it  becomes  the  rope  ; 
the  fasciculus  of  fibres  a  from  the  aorta  a  a 
is  also  seen  joining  this  band  at  its  inner  sur- 
face nearer  the  base.  By  the  union  of  these 
two  fasciculi  with  the  band  in  question,  the 
basial  half  of  the  posterior  boundary  of  the 
right  ventricle  is  formed.  By  pursuing,  in 
fig.  282,  this  band  or  combination  of  fibres, 
lettered  CpcaaaaC,  it  is  seen  to  form,  while 
it  is  gradually  twisting  upon  itself,  the  brim 
of  the  left  ventricle,  and  then  to  make  a 
sharp  twist  of  its  fibres  into  the  rope  R  R,  by 
which  means  they  are  rendered  the  internal 
fibres  of  the  left  ventricle ;  in  fig.  280  they 
may  be  traced  expanding-  again  into  a  layer, 
pursuing  the  same  spiral  sweep  from  left  to 
right,  but  from  the  base  towards  the  apex,  and 
inwardly  instead  of  outwardly.  Thus  the  de- 
monstration brings  us  back  to  our  starting-point. 

We  have  yet  to  trace  the  shorter  of  the  two 
bands  which  originate  in  the  splitting  of  the 
middle  mass  of  fibres,  cue,  in  fig.  278,  to 
embrace  the  right  ventricle.  This  view  ex- 
hibits only  the  inner  fibres  of  this  mass  as  they 
are  prolonged  into  the  inner  or  longer  of  the 
two  bands;  but  fig.  281  affords  an  outer  view 
of  this  mass  of  fibres  as  they  are  prolonged 
into  the  outer  or  shorter  band.  They  are  seen 
winding  spirally  up  from  the  apex  marked 
crc,  and  at  the  anterior  coronary  track,  act, 
they  split,  in  the  form  of  a  band,  from  the 
general  mass  to  pass  over  the  lower  half  of  the 
cavity  of  the  right  ventricle.  In  this  figure 
this  band  is  separated  and  left  extended,  in 
order  that  the  accessions  of  fibres  it  receives 
from  the  right  surface  of  the  septum  may  be 
seen,  which  are  the  fibres  a  from  the  aorta 
aa,  and  the  fibres  c  and  c  form  two  of  the 
carneee  columns  (not  in  view)  passing  obliquely 
down  from  right  to  left  to  the  anterior  edge  of 
the  septum,  from  which  they  extend  into  the 
band  which  is  lettered  Cacc,  and  unite  in- 
timately with  its  fibres.  When  the  band  is 
replaced  in  its  course  over  the  ventricle,  its 
accessory  fibres  are  made  to  reflect  at  an  acute 
angle  upon  themselves,  and  thus  form  the 
apicial  part  of  its  anterior  boundary.  This 
band  describes  one  spiral  circle  round  the  heart, 
arriving  again  at  the  anterior  coronary  track  at 
its  basial  extremity;  it  is  inserted  into  the 
aorta,  and  if  the  fibres  make  a  very  oblique 
approach  to  the  base,  they  will  be  also  inserted 
into  the  tendinous  margin  of  the  annulus  arte- 
riosus. The  continuation  of  this  band  round 
the  posterior  side  of  the  heart  can  be  traced  in 
fig.  279.  Its  width  is  equal  to  about  a  third 
of  the  heart's  axis ;  it  is  seen  marked  Cacc 
in  its  spiral  ascent  from  left  to  right,  passing, 
first,  a  little  below  the  middle  third  of  the  heart; 
at  the  posterior  coronary  track,  pet,  becom- 
ing the  middle  third,  and  afterwards  approach- 
ing gradually  the  base  m  its  way  to  its  points 
of  insertion  before-mentioned. 

As  the  tracing  the  fibres  from  the  circum- 
ference to  the  centre,  and  from  the  centre  to 
the  circumference,  is  a  matter  of  much  difficulty, 
and  as  the  description  has  been  attended  with 
much  detail,  it  is  desirable  that  a  more  general 


and  concise  view  by  means  of  a  diagram  should 
be  afforded  of  the  courses  which  the  fibres  take 
in  constructing  this  organ. 

Recapitulation.  (Vid.  the  diagram  fig. 283.) 
We  commence  tracing  the  fibres  of  the  heart 
from  its  very  centre.  The  fibres,  cc,  from  the  two 
carneas  columnae  of  the  left  ventricle,  lv,  are 
joined  by  the  fibres,  r,  from  the  rope  RR, 
after  those  fibres  of  the  rope  have  expanded 
and  formed  the  internal  layer  of  the  septum  S  ; 
in  winding  round  the  axis  of  this  cavity  they 
blend  together  as  the  initial  letters  crc  indi- 
cate. The  inmost  of  these  fibres  descend  as  far 
as  the  apex,  where  they  twist  sharply  round  and 
close  the  cavity,  by  which  means  they  construct 
the  apex,  and  become  the  superficial  fibres  of 
the  heart.  But  the  chief  bulk  of  this  mass  of 
blended  fibres  makes  a  spiral  sweep  from  left 
to  right  round  the  axis  above  the  apex ;  and  when 
it  has  described  two  circles,  crc,  it  splits  at 
the  anterior  edge  of  the  septum  into  two  bands, 
one  being  considerably  longer  than  the  other. 
The  longer  first  makes  one  circle  round  the  left 
ventricle,  then  another,  enclosing  both  ventri- 
cles. In  making  the  first  circle  it  passes 
through  the  septum  forming  its  middle  layer, 
and  on  reaching  its  posterior  edge  itreceives  from 
the  pulmonary  artery  accessory  fibres,  which 
have  crossed  over  the  cavity  of  the  right  ven- 
tricle, forming  the  inmost  layer  of  its  right  or 
proper  wall,  and  fibres  from  one  of  the  carnese 
columnae  of  this  ventricle,  and  from  the  aorta, 
being  marked  Cpca.  The  accessory  fibres 
are  not  represented,  as  they  would  have  ren- 
dered the  diagram  complicated  and  unintelligi- 
ble ;  but  they  are  indicated  by  their  initials 
being  added  in  the  lettering  of  the  bands. 
This  band  in  question  may  now  be  traced 
round  the  middle  third  of  the  left  ventricle 
advancing  towards  both  the  base  and  the  outer 
surface  of  the  heart;   on  completing  its  first 

Fig.  283. 


FIBRES  OF  THE  HEART. 


627 


circle  it  arrives  again  at  the  anterior  edge  of 
the  septum,  receives  another  fasciculus  of  fibres 
from  the  aorta,  and  is  marked  Cpcaa.  It 
is  then  seen  to  take  its  course  round  the  base 
and  in  front  of  the  right  ventricle.  As  it  passes 
by  the  right  aspect  of  the  aorta,it  again  receives 
from  it  a  fasciculus  of  fibres,  and  is  lettered 
Cpcaaa  ;  on  reaching  the  posterior  edge 
of  the  septum,  it  is  further  augmented  by  two 
accessions  of  fibres,  one  from  the  aorta  at  its 
posterior  aspect,  and  the  other  from  the  middle 
layer  of  the  septum.  This  combination  of 
fibres  from  various  sources  is  indicated  by  the 
combination  of  their  initial  letters,  CpcaaaaC. 
It  should  be  borne  in  mind  that  C  large 
is  the  synalepha  of  crc— the  initials  of  the 
primitive  mass  of  blended  fibres.  This  band, 
in  passing  along  the  base  of  the  left  ventricle, 
makes  at  first  a  gentle  twist  of  its  fibres  form- 
ing the  brim  of  this  chamber;  it  afterwards 
makes  a  sharp  twist  and  assumes  the  form  of  a 
rope,  by  which  means  its  fibres  are  transferred 
to  the  interior  of  the  ventricle.  In  descending 
this  chamber,  they  expand  again  into  a  layer, 
and  wind  spirally  round  its  cavity,  first  forming 
the  internal  layer,  R,  of  the  septum,  and  then 
associating  with  the  expanded  fibres  of  the  two 
carneae  columnae,  and  thus  arrive  at  the  points 
from  which  we  commenced  tracing  them.  We 
now  return  to  the  anterior  edge  of  the  septum, 
S,  in  order  to  trace  the  shorter  band.  At  this 
part  the  primitive  mass  of  blended  fibres  splits 
into  two  bands  :  the  longer  passes  behind  the 
right  ventricle  through  the  septum  as  already 
described  ;  the  shorter  passes  in  front.  The 
shorter  first  receives  a  considerable  accession 
of  fibres  from  the  right  surface  of  the  septum, 
which  pass  down  from  the  aorta,  and  from  the 
two  Games  columns  springing  from  this  sur- 
face :  it  is  lettered  Cacc  ;  it  describes  one 
spiral  circle  round  both  ventricles.  It  first 
passes  over  the  lower  half  of  the  right  ventri- 
cle, forming  the  apicial  band  of  the  middle 
layer  of  its  proper  wall,  and  then  round  the 
left  ventricle  in  an  oblique  direction  to  the  base, 
and  terminates  at  the  aorta  near  the  anterior 
coronary  track,  having  completed  its  spiral 
circle  round  the  heart. 

As  the  demonstration  has,  in  reference  to  the 
construction  of  the  septum  and  of  the  right 
ventricle,  been  unavoidably  disconnected,  it  is 
requisite  to  give  a  more  systematic  and  com- 
prehensive description  of  their  particular  for- 
mation. 

The  septum  is  composed  of  three  layers  :  a 
left,  a  middle,  and  a  right  layer.  The  two 
former  properly  belong  to  the  left  ventricle  ; 
and  the  last  or  right  layer  exclusively  pertains 
to  the  right  ventricle.  The  two  former  are 
composed  of  the  primitive  mass  of  fibres  de- 
rived from  the  rope  and  the  carnece  columns?  of 
the  left  ventricle ;  the  left  layer  being  formed 
of  the  expanded  fibres,  R,  of  the  rope,  Rii,^g.280, 
in  their  first  sweep  round  the  cavity  ;  and  the 
middle  layer  of  the  continued  fibres  of  the 
rope  in  its  second  sweep,  blended  with  the  ex- 
panded fibres  of  the  two  carneae  columnae. 
These  blended  fibres  form  the  extended  layer 
crc  ;  its  cut  edge  a  applies  itself  to  the  cut 


edge  b,  evidently  forming  the  middle  layer  of 
the  septum.  The  last  or  right  layer  of  the 
septum  has  not  the  same  origins  as  the  two 
former  have.  Its  fibres  arise  from  the  root 
and  lower  margin  of  the  valve  of  that  section 
of  the  aorta  which  pertains  to  the  right  ven- 
tricle, from  that  part  of  the  root  of  the  pulmo- 
nary artery  contiguous  to  the  aorta,  and  from 
the  carneae  columnae  of  the  right  surface  of  the 
septum.  The  fibres  attached  to  the  aorta  and 
pulmonary  artery  may  be  seen  in  fig.  278,  lettered 
a  and  r  respectively,  and  in  Jig.  280  the  fibres 
from  the  aorta  blended  with  those  of  the  car- 
neae columnae  are  exhibited  marked  acc, 
forming  the  right  layer  of  the  septum. 

The  right  ventricle. — Although  the  right  layer 
of  the  septum  belongs  anatomically  to  the  right 
ventricle,  yet  when  functionally  considered  it 
pertains,  as  well  as  the  other  layers,  entirely  to 
the  left.  For  the  concavity  of  this  layer  is, 
like  that  of  the  other  layers  of  the  septum,  to- 
wards the  cavity  of  the  left  ventricle,  and 
therefore  during  the  systole  approaches  the  axis 
of  this  cavity,  while  it  recedes  from  that  of  the 
right  ventricle  ;  thereby  assisting  in  the  propul- 
sion of  the  blood  from  the  former,  and  to  a 
limited  extent  counteracting  the  propulsive  effort 
of  the  latter  ventricle. 

The  right  ventricle  has,  therefore,  but  one 
proper  wall,  which  is  connected  to  the  left 
ventricle  in  a  manner  to  be  described  hereafter. 
The  right  chamber  should  be  divided  into  three 
channels :  the  auricular,  the  pulmonary  or 
ventricular,  and  the  apicial.  The  auricular  is 
that  which  receives  the  blood  directly  from  the 
right  auricle ;  the  pulmonary  is  that  formed 
by  the  fibres  which  arise  from  the  root  of  the 
pulmonary  artery  at  its  entire  circumference  : 
in  Jig.  278,  the  pulmonary  artery,  pp,  and  the 
fibres,  p,  are  seen  turned  a  little  upon  their 
axis,  by  which  means  the  fibres  are  rendered 
oblique,  and  the  channel  the  more  complete ; 
and  the  apicial  channel  is  that  which  forms  the 
channel  of  communication  between  the  other 
two,  and  which  extends  to  the  apex.  The  pro- 
per wall  is  considered  as  having  three  layers, 
the  superficial,  middle,  and  internal,  although 
they  cannot  always  be  detached  from  each 
other.  The  superficial  is  composed  of  the 
mere  superficial  fibres  of  this  wall,  having  the 
same  origins  and  terminations  as  have  its  sub- 
jacent fibres;  it  forms  the  left  wing  Cacc  of 
Jig.  279,  and  may  be  seen  in  Jig.  281,  raised 
from  the  right  ventricle  and  reflected  over  the 
base  marked  Cacc  The  middle  layer  is 
composed  of  two  bands,  the  apicial  and  the 
basial.  The  apicial  is  formed  of  the  first  semi- 
circular portion  of  the  shorter  band  of  the 
heart,  and  passes  over  the  lower  half  or  apicial 
channel  of  this  chamber ;  it  lies  separated  and 
extended  over  the  apex  of  Jig.  281,  marked 
Cacc  The  basial  bind  of  this  layer  is 
formed  of  the  first  semicircular  portion  of  the 
longer  band  as  it  makes  its  second  circle  round 
the  heart.  It  is  bisected  and  separated  as 
seen  at  Cpcaa,  of  Jig.  281;  in  its  natural 
situation  it  passes  over  the  pulmonary  and 
auricular  channels  of  this  ventricle,  and  is 
closely  connected  to  the  base.    The  internal 

2  t  2 


628 


FIBRES  OF  THE  HEART. 


layer  arises  chiefly  from  the  pulmonary  artery, 
PP  ;  it  first  forms  the  pulmonary  channel,  p, 
and  then  expands  into  a  layer  which  crosses 
obliquely  over  the  apicial  channel,  associated 
with  fibres  derived  from  one  of  the  carnea? 
columns.  The  basial  portion  of  this  layer 
which  crosses  over  the  auricular  channel,  can- 
not often  be  separated  from  the  fibres  of  its 
superjacent  band,  the  fibres  of  the  musculi 
pectinati  being  intricately  interwoven  with 
them.  When  this  layer  is  replaced,  its  lower 
loose  edge  applies  itself  to  the  anterior  boun- 
dary, a  b,  of  this  cavity,  and  is  lined  with  its 
internal  proper  membrane.  Of  the  three  layers 
composing  the  proper  wall  of  this  ventricle, 
two,  the  middle  and  inner  layers/,  are  confined 
at  the  edge  of  the  septum,  forming  thereby  the 
lateral  boundary  of  this  cavity. 

The  boundary  of  the  right  ventricle. — It  is 
true  that  every  part  of  the  internal  surface  of  this 
chamber  contributes  in  forming  its  boundary. 
But,  as  this  cavity  is  formed  chiefly  by  the 
splitting  of  the  mass  of  fibres  into  layers  and 
by  their  re-union,  it  is  clear  that  unless  the 
layers  so  separated  were  well  secured  at  their 
points  of  junction,  their  separation  would  pro- 
gressively increase,  and  the  cavity  enlarge  to  a 
fatal  extent  by  the  repeated  dilatations  to  which 
it  is  subjected.  The  mode  of  union  which 
secures  this  lateral  boundary  merits  therefore 
particular  notice.  As  the  lateral  boundary 
corresponds  to  the  edge  of  the  septum,  it  admits 
of  the  same  division  into  anterior  and  posterior. 
The  anterior  boundary  being  formed  by  the 
splitting  of  the  layers,  and  the  posterior  by  their 
re-union,  their  respective  modes  of  construction 
are  not  precisely  similar.  The  anterior  boun- 
dary is  principally  formed  by  a  certain  set  of 
fibres  winding  and  reflecting  upon  themselves, 
as  shewn  in  fig.  281.  The  basial  part  of  this 
boundary,  a  b,  is  formed  of  fibres  a,  from  the 
aorta  a  a,  winding  over  the  pulmonary  channel 
of  fibres  p,  in  contributing  to  form  the  band 
Cpcaa.  The  fibres  of  this  channel  also  con- 
tribute to  form  this  part  of  the  boundary, 
as  is  represented  in  fig.  278.  The  apicial  part 
of  this  boundary  is  obviously  constructed  by 
the  fibres  acc  which  form  the  right  layer  of 
the  septum  being  prolonged  into  the  extended 
band,  which  on  being  replaced  occasions  them 
to  be  doubled  upon  themselves  in  passing  over 
the  apicial  channel  in  association  with  the  fibres 
of  this  band. 

The  posterior  boundary  is  constructed  by 
the  re-union  of  the  fibres  which  pass  in  front 
of  the  cavity  with  others  which  pass  behind  it, 
and  by  the  attachment  of  some  of  the  fibres  at 
the  base  to  the  aorta.  The  basial  half  of  this 
boundary  being  formed  by  the  conjunction  of 
the  under  fibres  of  the  basial  band  Cpcaaa, 
fig.  282,  with  a  fasciculus  of  fibres,  c,  emerging 
from  the  middle  layer  of  the  septum,  and  with 
another  fasciculus  of  fibres,  a,  jig.  278,  arising 
from  the  aorta,  aa.  That  part  of  the  boundary 
contiguous  to  the  base  is  greatly  strengthened 
by  the  outer  fibres  of  the  basial  band  being 
attached  to  the  aorta  at  its  posterior  aspect. 
And  the  apicial  half  of  the  posterior  boundary 
being  formed  by  the  conjunction  of  the  prin- 


cipal part  of  the  internal  layers  of  fibres  which 
cross  obliquely  the  cavity  of  the  right  ventricle 
with  the  chief  part  of  the  fibres  of  the  middle 
layer  of  the  septum  as  they  emerge  at  its  pos- 
terior edge,  where  they  freely  decussate.  In 
fig.  281  the  internal  layer  of  fibres,  pc,  is  seen 
crossing  the  cavity  obliquely  towards  the  apicial 
part  of  the  posterior  boundary,  and  in  fig.  282 
their  conjunction  with  the  fibres  which  emerge 
from  the  septum  is  seen  forming  a  firm  union. 
But  the  lateral  boundary  is  rendered  doubly 
secure  by  the  curious  circumstance  of  the 
coronary  vessels,  deeply  penetrating  the  sub- 
stance of  the  heart  along  the  entire  edge  of  the 
septum,  stitching  down,  as  it  were,  just  on  the 
outside  of  the  boundary,  all  the  fibres  which 
form  it. 

The  conical  form  of  the  heart. — The  only 
point  now  remaining  for  consideration  is  the 
conical  form  of  the  heart.  This  form  admits  of 
the  following  explanation.  Along  the  central 
cavity  of  the  left  ventricle  are  placed  the  two 
carneee  columnar,  the  length  of  which  is  equal 
to  the  lower  three-fourths  of  the  length  of  the 
axis  of  this  cavity.  The  fibres  of  these  two 
bodies  radiate,  as  represented  in  fig.  278  ;  and 
the  radiated  fibres  wind  round  the  axis  closely 
upon  them,  as  is  seen  in  fig.  280.  By  this 
radiation,  instead  of  all  the  fibres  passing 
longitudinally,  which  would  have  preserved 
these  bodies  in  a  state  of  equal  thickness 
throughout  their  length,  they  are  progressively 
parting  with  their  fibres,  retaining  but  a  few, 
which,  by  their  longitudinal  course,  reach  the 
apex ;  consequently  these  columns  gradually 
diminish,  becoming  pyramidal,  and  forming 
together  an  inverted  cone ;  and  as  the  fibres  in 
well-formed  hearts  wind  closely  round  these 
columns,  the  entire  ventricle  gently  assumes 
the  form  of  a  cone.  And  although  the  right 
ventricle  is,  as  it  were,  appended  to  the  left, 
yet  it  is  not  so  connected  to  it  as  to  destroy  the 
conical  form,  but,  on  the  contrary,  in  such  a 
manner  as  to  form  a  concave  parabolic  section 
of  a  cone  which  adapts  itself  to  the  gentle  cone 
of  the  left  ventricle.  The  two  ventricles  thus 
united  assume  the  form  of  the  more  rapid  cone 
of  the  heart. 

Construction  of  the  auricles. — For  the  pur- 
pose of  ascertaining  the  mode  in  which  the 
fibres  form  the  auricles,  large  hearts,  as  those  of 
bullocks  and  horses,  should  be  selected.  Not- 
withstanding the  muscularity  of  the  auricles  is 
very  much  greater  in  large  than  in  small  hearts, 
yet  the  plan  is  the  same  in  both,  although  less 
developed  in  the  latter. 

The  fibres  of  the  auricles  arise  chiefly 
from  the  tendinous  margins  of  the  annulus 
venosus  and  annulus  arteriosus ;  they  ascend 
interiorly,  and  arrange  themselves  into  several 
columns,  which  give  off  branches.  Some  of  the 
branches  form  a  simple  communication  between 
two  of  the  trunk-columns,  but  most  of  them 
subramify,  by  which  means  the  interstices  are 
filled  in.  In  small  hearts  the  columns  are  not 
only  more  slender,  but  more  numerous  and  in- 
terlaced ;  in  these,  the  interstices  in  many 
places  are  not  filled  in,  the  internal  and  external 
proper  membranes  being  in  contact,  and  thus 


FIBRES  OL'  THE  HEART. 


629 


com  pleting  the  wall.  Fig.  284  affords  an  interior 
view  of  a  section  of  the  right  auricle,  in  which, 

Fig.  284. 


the  lining  membrane  being  removed,  the  fibres 
are  seen  arising  from  the  tendinous  margin  of 
the  annulus  venosu3  av,  forming  the  internal 
part  of  the  wall  of  this  auricle,  and  in  their 
progress  up  arranged  into  columns,  c,  the 
branches  of  which  are  entwined  together  so  as 
to  construct  the  appendix.  These  convo- 
luted columns  at  the  posterior  aspect  of  the 
appendices  are  flattened,  as  shown  in  fig.  285,  c, 
where  their  fibres  are  associating  together,  and 


Fig.  285. 


in  passing  round  the  edges  to  the  anterior  sur- 
face becomeevenly  arranged  again, as  seen  in  the 
appendix  a  of  the  right  auricle,  ra,  oifig.  286. 
Thus  far  the  construction  of  the  two  auricles 


Fig.  286. 
CS  D 


CI 


agrees,  the  fibres  of  each  arising  from  its  respec- 
tive annulus,  forming  first  the  inner  part  of  the 
wall  of  the  auricle,  and  then  being  arranged 
into  columns  which  entwine  together,  forming 
the  whole  of  the  appendix.  The  fibres  of  the 
right  auricle,  after  having  formed  the  wall  of 
this  cavity,  are  prolonged  to  form  the  outer  part 
of  the  wall  of  the  left  auricle.    As  may  be  seen 


in  Jig.  286,  the  fibres  which  extend  from  the  con- 
voluted fibres  of  the  posterior  surface  of  the 
right  auricle,  ra,  wind  evenly  arranged,  some 
over  the  apex,  and  others  round  the  auricle, 
marked  c,  completing  the  outer  part  of  the  wall 
of  the  entire  auricle :  they  then  meet  at  the 
septum  S,  across  which  they  pass  associated 
together,  marked  d,  and  on  reaching  the  left 
auricle  divide  into  an  upper  portion  and  an 
anterior  and  posterior  band.  The  tipper  portion 
is  composed  of  the  continued  fibres  d,  which 
proceed  up  the  appendix  and  encircle  its  apex. 
The  anterior  band  e  winds  round  the  left  au- 
ricle la,  and  on  reaching  the  root  of  the 
aorta  k,  its  fibres  become  more  or  less  at- 
tached to  it  in  different  hearts  ;  in  its  course 
upwards,  marked  f,  when  it  has  completed  a 
circle  it  passes  behind  the  fibres  which  form  the 
first  part  of  the  circle  to  enter  into  the  formation 
of  the  fleshy  columns  of  the  appendix.  The 
posterior  band  passes  over  the  left  auricle  be- 
tween the  appendix  a  and  the  vena  cava  su- 
perior cs;  and  in  fig.  285  it  can  be  traced, 
coming  over,  marked  g,  and  passing  along  the 
posterior  surface  of  this  auricle  la,  including 
in  its  course  the  posterior  edge  of  the  appendix 
a  ;  the  fibres  which  pass  along  the  posterior 
edge  of  the  appendix,  on  arriving  at  the  ante- 
rior edge,  separate  from  the  band  g  to  pursue 
their  course  round  the  edge  of  the  appendix, — 
now  along  the  anterior  edge, — and  join  the 
fibres  d,  which  cap  the  apex.  This  division 
of  the  band  which  encircles  the  appendix  is  con- 
stant, and  evidently  affords  particular  strength 
to  its  edge.  The  band  itself  g  winds  down 
towards  the  base,  expanding  and  surrounding 
the  orifices  of  the  pulmonary  veins  p;  some 
of  its  fibres  become  lost  on  the  surface  of  the 
auricle,  and  the  others  may  be  traced  to  the  root 
of  the  aorta. 

This  band  cannot  be  completely  detached  in 
consequence  of  some  of  its  fibres  being  inter- 
woven with  its  subjacent  fibres. 

The  left  auricle,  without  the  addition  of  these 
bands,  would  nearly  balance  in  substance  and 
strength  the  right ;  their  addition  gives,  there- 
fore, to  the  left  a  considerable  preponderance 
in  these  respects  over  the  right  auricle. 

The  septum  S  is,  mfig.  286,  shown  to^be  com- 
posed, superiorly,  of  the  transverse  band  of 
fibres  d,  which  passes  from  the  right  to  the 
left  auricle ;  in  its  middle  part,  of  the  ascending 
fibres  H,  which  arise  from  the  root  of  the  aorta 
k,  and  pass  up  behind  the  band  d,  some 
joining  this  band,  the  others  proceeding  to  the 
vena  cava  superior  cs  ;  and  lastly,  at  the  infe- 
rior and  posterior  part,  of  a  slender  fasciculus 
of  fibres  which  crosses  the  septum  transversely 
between  the  root  of  the  aorta  k  and  the  vena 
cava  inferior  ci,  extending  from  the  annulus 
venosus  to  the  left  auricle,  but  which  cannot  be 
seen  in  this  figure. 

In  concluding  these  remarks  on  the  construc- 
tion of  the  auricles,  it  may  be  mentioned  that 
in  theheartsof  large  animals  a  great  difference  ex- 
ists in  the  structure  of  the  two  vena?  cava?,  the 
superiorbeingparticularly  fleshy,and  the  inferior 
apparently  devoid  of  muscularity. 

(H.  Scarle.) 


630 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


HEART,  ABNORMAL  CONDITIONS 
OF. — There  is  no  organ  in  the  body  in  which 
the  various  deviations  from  the  normal  state  have 
been  more  diligently  or  more  carefully  explored 
than  the  heart ;  nor  ought  it  to  be  otherwise, 
when  we  take  into  account  the  important  part 
which  the  heart  performs  in  the  organism,  and 
the  serious  nature  of  the  derangements  which 
its  diseases  in  general  produce, — how  many  or- 
gans and  how  many  functions  are  involved  in 
the  break-up  which  too  often  follows  the  oc- 
currence of  morbid  alterations  of  the  heart. 
The  great  frequency*  of  diseases  of  this  organ, 
and  the  manifest  and  tangible  shape  which  these 
diseases  assume,  as  well  as  the  little  liability 
of  its  component  structures  to  those  appearances 
which  have  been  denominated  pseudo-morbid, 
these  circumstances  render  it  comparatively 
easy  to  detect  and  observe  its  abnormal  condi- 
tions. To  one  who  has  made  the  natural 
condition  of  the  whole  organ,  as  well  as  of  its 
several  parts,  the  subject  of  careful  study, 
there  is  no  field  of  investigation  in  morbid 
anatomy  which  presents  fewer  difficulties. 

The  records  of  anatomy  are  not  without  in- 
stances of  total  absence  of  the  central  organ  of 
circulation  (acardia);  and  it  may  well  be 
supposed  that  such  cases  would  also  afford 
examples  of  the  defective  development  of  other 
not  less  important  organs.  In  short,  it  is  in  ace- 
phalous and  anencephalous  foetuses  that  the  heart 
is  most  frequently  wanting,  although  its  ab- 
sence is  not,  as  some  observers  suppose,  a  con- 
stant characteristic  of  these  forms  of  monstro- 
sity ;  nor  on  the  other  hand  does  acardia  ne- 
cessarily imply  acephalia  or  anencephalia. 
Thus  in  the  case  recorded  by  Marriguesf,  and 
quoted  at  length  in  Breschet's  Memoir  Sur 
I'Ectopie  (lit  Caw,Jthe  brain  was  present,  while 
all  the  usual  contents  of  the  thorax  were 
wanting,  their  place  having  been  supplied  by 
a  large  bladder  full  of  clear  water  which  occu- 
pied the  whole  thoracic  cavity.  The  details 
of  another  case  were  communicated  many 
years  ago  to  the  Royal  Society  by  Sir  Benjamin 
Brodie,  and  are  published  in  the  volume  of 
their  Transactions  for  1809.  The  foetus  was 
one  of  twins,  as  is  most  frequently  the  case 
when  the  heart  is  absent.  The  brain  was 
"  nearly  the  natural  size,  and  nothing  unusual 
was  observed  in  it."  The  heart,  thymus  gland, 
and  pleura  were  absent,  and  the  lungs  most 
imperfectly  developed.  The  aorta,  however, 
was  tolerably  perfectly  developed,  but  as  a  con- 
tinuation of  the  umbilical  artery  extending 
from  the  left  groin  upwards  on  the  fore-part  of 
the  spine  to  the  upper  part  of  the  thorax,  where 
it  gave  off  the  two  subclavian,  and  afterwards 
divided  into  the  two  carotid  arteries  without 
forming  an  arch.  The  external  and  internal 
iliac  arteries  of  the  left  side  came  from  this 
artery  in  the  left  groin  immediately  after  it  left 
the  umbilicus,  and  the  common  iliac  of  the 

*  Out  of  520  post-mortem  inspections  recorded 
by  Dr.  Clendinning,  170  were  cases  of  diseased 
heart,  or  about  33  per  cent. —  Vide  his  Crooniaa 
Lectures  for  1838,  Med.  Gazette,  vol.  xvi.  p.  657. 

f  Mem.  de  Mathem.  pres.  a  l'Acad.  des  Sc.  t.  iv. 

£  Rep.  Gen.  d'Anat.  et  de  Physiol,  t.  ii. 


right  was  given  off  from  it  in  the  lumbar  region 
after  it  had  gained  the  situation  of  the  aorta. 

We  shall  first  examine  the  congenital  devia- 
tions from  the  normal  state  hi  this  organ,  and 
secondly  its  morbid  alterations. 

I.  Congenital  abnormal  conditions. — These 
are  observed  under  three  heads.  1.  Congeni- 
tal aberrations  of  position,  or  ectopia?  of  the 
heart.  2.  Malformations  by  defect  in  deve- 
lopement.  3.  Malformations  by  excess  of  de- 
velopement. 

1.  Congenital  aberrations  of  position. — The 
simplest  form  of  malposition  is  that  in  which 
the  heart  retains  the  vertical  position  which  it 
occupies  during  the  early  periods  of  intra-ute- 
rine  life  ;  but  of  this  the  authentic  instances  are 
rare.*  Better  known  is  that  deviation  in  which 
the  heart  is  directed  downwards,  forwards,  and 
to  the  right  side.  This  malposition  generally 
occurs  as  a  part  of  a  universal  transposition  of 
the  abdominal  and  thoracic  viscera,  of  which 
many  well-marked  examples  are  now  on  re- 
cord ;  however,  it  sometimes,  although  more 
rarely,  exists  alone  without  ectopia  of  any 
other  organ.  Breschetf  records  four  cases  of 
this  latter  kind.  Otto}  has  met  with  three  in- 
stances, and  many  other  examples  are  scattered 
among  the  records  of  anatomists.§  In  this 
form  of  transposition  of  the  heart,  the  aorta 
sometimes  passes  down  along  the  right  side  of 
the  spine,  and  at  other  times  down  its  left  side. 
In  the  latter  case  the  transposition  is  not  so 
complete,  the  ventricles  retaining  their  natural 
position  with  reference  to  the  anterior  and  pos- 
terior aspects  of  the  body.  Again  the  heart 
may  be  pushed  too  much  to  the  left  side,  as  a 
mechanical  result  of  congenital  diaphragmatic 
hernia  of  the  right  side;  and  it  has  been 
found  laid  across  in  the  chest  from  one  side  to 
the  other,  the  apex  being  at  one  time  directed 
to  the  right  side,  and  at  another  to  the  left, 
or  turned  upside  down,  the  base  toward  the 
abdomen,  or  in  that  cavity,  the  apex  upwards 
still  remaining  in  the  thorax. 

In  such  cases  as  have  been  just  detailed, 
the  heart  still  retains  its  title  to  be  considered 
as  a  thoracic  viscus ;  but  other  and  more  re- 
markable malpositions  of  it  have  been  found, 
where  it  is  excluded  from  that  cavity.  These 
are,  in  fact,  congenital  thoracic  herniae  in  va- 
rious directions,  of  which  Breschet,  whose 
memoir  already  referred  to  contains  the  most 
complete  account  of  this  subject,  enumerates 
three  principal  varieties,  according  to  the  situ- 
ation in  which  the  heart  is  found,  viz.  the 
superior  or  cervical  displacement,  the  abdo- 
minal or  inferior,  and  the  thoracic  or  anterior. 

Thus  Breschet  details  a  case  in  which  the 
heart,  lungs,  and  thymus  gland  were  all  con- 
tained in  the  anterior  part  of  the  neck,  forming 
a  large  tumour  under  the  lower  jaw.  The 
point  of  the  heart  was  attached  to  the  base  of 
the  tongue,  and  placed  between  two  branches 
of  the  lower  jaw.    The  thorax  was  occupied 

*  Sandifort,  Obs.  Anat.  Path, 
t  Op.  cit. 

f  Selt.  Beobacht.  part  i,  p.  95,  and  part  ii.  p.  47. 
§  Iieuss'  Rcpertorium,  vol.  x.  p.  90-91. 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


631 


by  the  abdominal  viscera,  which  had  passed 
up  through  a  fissure  in  the  diaphragm.  In  a 
second  instance  of  this  high  displacement  the 
apex  of  the  heart  adhered  to  the  palate;  but  in 
this  case  the  malposition  appears  to  have  been 
owing  to  a  morbid  adhesion  of  the  umbilical 
cord  to  the  head,  by  which  all  the  viscera  were 
drawn  out  of  their  natural  positions.^  A  less 
degree  of  cervical  displacement  is  where  the 
heart  is  found  immediately  above  the  thorax, 
in  the  front  of  the  neck,  which,  however,  is 
very  rare. 

When  the  malposited  heart  is  found  in  the 
abdomen,  the  diaphragm  is  generally  deficient 
to  a  greater  or  less  extent. 

In  a  case  narrated  by  Mr.  Wilson,*  the 
heart  was  in  a  fissure  on  the  convex  surface  of 
the  liver — the  infant  lived  seven  days  !  Ramel 
also  gives  an  instance  of  the  heart  being  placed 
in  the  region  of  the  stomach,  and  the  indi- 
vidual in  whom  he  observed  it  was  ten  years 
of  age.  And  in  the  extraordinary  case  related 
by  Deschamps,  the  heart  occupied  the  place  of 
the  left  kidney  !  Not  the  least  marvellous  cir- 
cumstance about  this  case  is,  that  the  indi- 
vidual was  an  old  soldier,  who  had  served 
several  campaigns,  and  enjoyed  excellent  health, 
with  the  exception  of  nephritic  pains,  which 
ultimately  procured  him  his  discharge  from  the 
service.  The  right  kidney  alone  existed,  and 
was  found  in  a  state  of  suppuration. f  The 
vessels  emanating  from  the  heart  passed  through 
an  opening  in  the  diaphragm  into  the  thorax. 

Dr.  Paget  mentions  some  instances  of  vari- 
eties of  position  which  parts  of  the  heart  may 
assume  with  respect  to  each  other.  In  a  case 
recorded  in  the  first  volume  of  the  Edinburgh 
Medico-ChirurgicalTransactions  by  Dr. Holmes 
of  Canada,  the  right  auricle,  enlarged  to  the 
capacity  of  a  pint,  was  found  to  open  into  the 
left  ventricle  in  place  of  the  right,  into  which, 
however,  the  blood  afterwards  found  its  way 
through  a  small  perforation  in  the  septum  of  the 
ventricles. 

The  aorta  and  pulmonary  artery  may  arise 
from  one  ventricle  alone,  either  right  or  left,  and 
instances  of  each  preternatural  origin  are  pre- 
served in  the  museum  of  the  Edinburgh  Col- 
lege of  Surgeons. 

When  the  anterior  wall  of  the  thorax  is  de- 
ficient, the  heart  may  be  found  protruding 
through  the  opening,  as  in  fissure  of  the  ster- 
num, or  a  defect  in  its  inferior  portion  as  well 
as  in  some  of  the  ribs;  nor  does  this  mal- 
position necessarily  destroy  life.  Where  the 
deficiency  is  not  confined  to  the  wall  of  the 
thorax,  but  also  extends  to  the  abdomen,  the 
stomach,  liver,  and  spleen,  with  the  heart,  are 
found  occupying  a  large  hernial  sac  in  front 
of  the  opening,  which  is  sometimes  contained 
in  the  sheath  of  the  umbilical  cord,  or  covered 
by  an  extension  of  the .  common  integument. 
In  the  case  of  simple  fissure  of  the  sternum, 
it  has  occurred  that  the  heart  had  not  protruded, 
but  occupied  its  natural  position,  being  simply 

*  Phil.  Trans.  1798. 

t  Quoted  by  Breschct  from  the  Journ.  Gen.  de 
Med.  t.  xxvi. 


exposed  to  view  by  the  abnormal  opening  in 
the  chest.* 

2.  Malformations  by  defect  in  development. 
— Our  limits  compel  us  to  restrict  the  present 
account  to  little  more  than  an  enumeration  of 
the  congenital  malformations  which  may  be 
placed  in  this  class.  In  these  malformations 
we  find  a  diminution  in  the  normal  number  of 
the  heart's  cavities,  either  from  a  very  early 
arrest  in  the  developement  of  the  whole  organ, 
or  from  a  total  non-developement  of  the  sep- 
tum, or  from  its  imperfect  developement.  A 
few  rare  instances,  many  of  which  have  oc- 
curred in  the  lower  quadrupeds,  of  an  ex- 
tremely imperfect  state  of  the  heart,  are  quoted 
by  Otto,  in  which  that  organ  seemed  to  consist 
of  nothing  but  a  fleshy  enlargement  at  the 
commencement  of  the  aorta,  described  as  "  a 
mere  fleshy  mass  without  any  cavity,"  or  "  a 
longish  solid  mass  from  which  the  vessels  arise," 
"  or  a  mere  expanded  vascular  trunk." 

The  dicalious  heart  of  Hunter,  or  that  with 
two  cavities,  exists  at  a  very  early  period  of  the 
developement  of  the  Mammiferous  embryo: 
it  is  described  and  figured  by  Baer  in  the  em- 
bryo of  a  dog,  of  three  weeks,  only  four  lines 
in  length,  as  consisting  of  a  single  auricle  and 
a  single  ventricle.f  The  permanence  of  this 
state  of  the  heart,  similar  to  the  natural  con- 
dition of  that  organ  in  fishes,  constitutes  one 
of  the  simplest  but  rarest  malformations  in  the 
human  subject.  From  the  ventricle  a  single 
vessel  arises  which  subdivides  into  the  aorta 
and  pulmonary  artery.  A  very  perfect  example 
of  this  malformation  is  described  by  Mr. Wilson 
in  the  Philosophical  Transactions  for  1798; 
it  is  the  same  case  which  has  been  already  al- 
luded to  as  affording  an  instance  of  malposition. 
In  this  case  the  blood  was  returned  from  the 
lungs  by  two  veins  which  joined  the  superior 
vena  cava,  and  entered  the  auricle  along  with 
it,  the  inferior  cava  being  formed  in  the  usual 
way.  Other  examples  are  recorded  by  Mr. 
Slandert,J  Dr.  Farre,§  Professor  Mayer,[|  and 
Dr.  Ramsbotham.^f  H 

The  heart  with  three  parities  (tricoilia  of 
Hunter),  that  is,  containing  two  auricles  and 
one  ventricle,  or  that  form  of  the  heart  which 
belongs  to  the  Batracbian  reptiles,  must  be 
very  rare,  if  indeed  it  ever  occurs. 

A  case  is  related  by  Breschet,**  in  which  a 

*  The  reader  who  desires  farther  information  on 
the  congenital  ectopia  of  the  heart,  may  consult 
Breschet's  memoir  already  referred  to;  Dr.  Paget's 
Inaugural  Dissertation  on  Malformations  of  the 
Heart,  Ed.  1831  ;  the  article  on  Displacement  of 
the  Heart,  by  my  valued  friend  Dr.  Townsend,  in 
the  Cyclopedia  of  Practical  Medicine,  vol.  ii.; 
Fleischman  de  vitiis  congen.  circa  thoracem  et 
abdomen,  Erlang.  1810;  YVeese  de  Ectopia  Cordis, 
Bcrol.  1819  ;  and  Haan  de  Ectopia  Cordis,  Bonn. 
1825. 

t  De  ovi  Mammal,  et  Hominis  Genesi ;  also 
in  Forbes'  Journal  another  case  by  Baer,  vol.  i. 
plate  2,  fig.  9,  human  embryo  about  the  fifth 
week. 

X  Phil.  Trans.  1805. 

$  On  the  Malformations  of  the  Human  Heart. 

Arch.  Gen.de  Med.  torn.  xvii. 
1  Lond.  Med.  and  Phys.  Journal. 
**  Rep.  Gen.  d'Anat.  torn.  ii. 


632 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


single  ventricle  and  two  auricles  existed,  but 
along  with  an  imperfect  inter-auricular  septum. 
The  two  auricles,  therefore,  virtually  formed 
one  cavity.  A  similar  case  is  recorded  by 
Wolff,*  and  is  remarkable  from  the  fact  that 
the  individual  in  whom  it  was  observed  lived 
to  the  age  of  twenty-two.  These  hearts  then 
do  not  exactly  correspond  to  the  tripartite  heart 
of  Batrachia,  inasmuch  as  the  two  auricles 
communicate.  A  similar  case,  shewn  by  Mr. 
Lawrence  to  Dr.  Farre,t  explains  more  par- 
ticularly the  true  nature  of  the  malformation. 
It  was  a  deficiency  of  the  septa,  both  auricular 
and  ventricular,  the  latter  having  been  alto- 
gether wanting  ;  the  former  consisting  only  of 
a  small  muscular  band,  which  left  a  large  fora- 
men ovale  without  a  valve,  but  the  vence  cavae 
and  pulmonary  veins  opened  into  their  respec- 
tive auricles,  which  externally  appeared  to  be 
quite  separate.  The  ventricle  communicated  with 
the  two  auricles  by  a  single  ostium  ventriculi, 
and  the  aorta  and  pulmonary  artery,  the  en- 
trance of  the  latter  being  somewhat  contracted, 
arose  side  by  side  from  the  left  part  of  the 
ventricle. 

Most  of  the  other  defective  malformations  of 
the  heart  consist  in  preternatural  communica- 
tion between  the  right  and  left  cavities,  resulting 
from  various  causes.  1,  The  communication  is 
direct,eitherfromanopen foramen  ovale,  orfrom 
an  imperfection  in  the  septum  of  the  auricles 
or  of  the  ventricles,  or  from  the  co-existence 
of  all  three  or  any  two  of  them.  2.  The  com- 
munication is  indirect,  the  septa  being  perfect, 
but  the  ductus  arteriosus  remaining  pervious. 

The  open  foramen  ovale  is  by  far  the  most 
common  of  all  the  malformations  of  the  heart; 
numerous  examples  of  it  are  now  on  record, 
as  found  in  persons  of  all  ages.  The  opening 
of  communication  varies  considerably  as  to  size, 
apparently  according  to  the  period  of  develope- 
ment  at  which  the  arrest  took  place ;  the  di- 
ameter of  the  opening  ranges  between  two  and 
twelve  lines.  We  know  that  the  size  of  this 
orifice  is  inversely  as  the  size  of  the  foetus 
during  intra-uterine  life,  whence  we  may  infer 
that  the  larger  the  opening  is,  the  earlier  must 
have  been  the  period  at  which  further  deve- 
lopement  ceased.  In  many  instances  the  valve- 
like portions  which  bound  this  opening  have 
acquired  their  full  developement,  and  the  only 
defect  seems  to  be  the  non-adhesion  of  their 
margins,  so  as  to  close  the  cavity ;  this  non- 
adhesion  again  may  involve  the  whole  extent 
of  the  margins  of  the  valves,  or  only  a  very 
small  portion,  thus  leaving  a  large  or  small 
opening  of  communication  between  the  two 
auricles.  Such  a  condition  of  the  inter-auri- 
cular septum  does  not  necessarily  occasion 
that  intermixture  of  the  blood  which  so  com- 
monly accompanies  the  communication  be- 
tween the  right  and  left  cavities ;  and  where 
the  opening  is  small,  of  course  this  inter- 
mixture is  the  less  likely  to  occur.  Thus  every 
anatomist  must  be  aware  that  it  is  not  an  un- 
frequent  occurrence  to  find  an  opening  large 

*  In  Kreysig's  die  Krankeit.  Herz.  B.  iii. 
t  Loc.  cit.  p.  30. 


enough  to  introduce  a  goose-quill  in  the  hearts 
of  adults  who  during  life  exhibited  no  derange- 
ment of  the  circulation,  and  who  died  of  dis^ 
eases  totally  unconnected  with  the  heart.  On 
the  other  hand  we  are  often  surprised  at  the 
amazing  size  of  the  opening  in  the  hearts  of 
persons  who  have  lived  many  years,  and  have 
shewn  less  disturbance  of  functions  than  the 
freedom  of  the  communications  between  the 
auricles  would  warrant  us  to  expect.  In  many 
of  these  cases  the  absence  or  mildness  of  sym- 
ptoms may  be  accounted  for  by  the  obliquity 
of  the  passage  of  communication,  and  the 
overlapping  of  the  margins  of  the  valves,  so 
that  at  times  they  completely  oppose  the  flow 
of  the  blood  from  one  side  of  the  heart  to  the 
other,  whilst  at  other  times  the  passage  is  left 
more  or  less  free.  In  a  heart  which  I  lately  saw 
in  the  Museum  of  Guy's  Hospital/the  circumfe- 
rence of  the  open  foramen  ovale  was  equal  to 
that  of  a  halfpenny,  (i-  e.  about  an  inch  in 
diameter,)  and  yet  the  patient  had  lived  to  the 
adult  period;  and  in  a  case  quoted  by  Dr. 
Farre  from  Corvisart,  the  foramen  ovale  was 
"  more  than  one  inch  in  diameter."  Such  cases 
strongly  favour  the  opinion  that  the  foramen 
undergoes  considerable  enlargement  when  once 
all  impediment  to  the  passage  of  the  current 
of  blood  from  one  side  to  the  other  has  been 
removed.*  More  rarely  we  find  the  fossa 
ovalis  cribriform,  and  thus  several  small  open- 
ings of  communication  exist  between  the 
auricles,  and  sometimes  in  addition  to  the  un- 
closed foramen  ovale,  we  have  a  true  imper- 
fection in  the  septum,  as  in  the  case  related  by 
Walter,t  and  another  by  Otto.J 

Imperfection  in  the  septum  ventriculorum  is 
a  much  less  frequent  cause  of  the  communi- 
cation between  the  right  and  left  hearts  than 
the  open  foramen  ovale.  The  opening,  varying 
in  diameter  from  two  lines  to  about  an  inch, 
is  situated  towards  the  base  of  the  septum, 
so  that  the  ventricles  communicate  at  their 
bases;  a  fact  which  evidently  indicates  that  the 
opening  results  from  the  progress  of  the  de- 
velopement of  the  septum  being  arrested  near 
its  completion,  since  the  base  of  the  septum 
is  the  last  portion  formed.  The  orifice  of  com- 
munication generally  opens  upwards  towards 
the  orifices  of  both  arteries,  and  is  bounded 
inferiorly  by  the  rounded  smooth  edge  of  the 
ventricular  septum.  In  these  cases  the  aorta 
opens  into  both  ventricles  and  appears  to  arise 
from  both ;  and  frequently  the  orifice  of  the 
pulmonary  artery  is  contracted  and  more  rarely 
obliterated,  either  from  non-developement  or 
from  previous  morbid  action ;  moreover,  ap- 

*  It  is  not,  perhaps,  correct  to  suppose  every 
case  of  open  foramen  ovale  congenital  ;  at  least 
it  is  certain  that  many  patients  date  their  symptoms 
from  a  fall  or  blow  ;  and  even  without  any  evi- 
dence of  the  occurrence  of  such  violence  many 
cases  have  been  observed  which  can  be  explained 
only  by  supposing  that  the  forameaovale  had  been 
morbidly  re-opened.  See  A  bemethy  in  Phil. Trans. 
1798  ;  Otto,  Selt.  Beobachtungen  ;  and  Pasqualini, 
Memorie  sulla  frequente  apertura  del  foramine 
ovale  rinvenuta  nei  cadaveri  dei  tisici.  Rom.  1827. 

t  Observat.  Anatom. 

i  Palhol.  Anat.  by  South. 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


633 


parenfly  as  a  consequence  of  this  contracted 
state  of  the  arterial  outlet  of  the  right  ventricle 
the  ductus  arteriosus  often  remains  open, which, 
by  its  communication  with  the  aorta,  conveys 
some  blood  into  the  pulmonary  arteries  from 
that  vessel ;  and,  as  a  further  complication,  the 
right  ventricle  is  very  small  and  appears  merely 
as  an  appendage  to  the  left ;  sometimes  also 
the  left  auricle  is  very  small,  while  the  right  is 
much  dilated. 

Where  so  much  complication  exists,  as  that 
just  detailed,  one  is  only  surprised  that  vitality 
can  be  at  all  supported  after  extra-uterine  life 
has  commenced ;  yet  we  find  that  children  with 
hearts  so  malformed  live  three,  four,  or  five 
days,  and  even  as  many  weeks  or  months; 
but  where  the  perforation  of  the  septum  is  not 
accompanied  with  the  contracted  state  of  the 
pulmonary  artery,  life  may  be  prolonged  to  a 
considerable  period.  Thus,  Louis  quotes  one 
case  of  a  general  officer  (age  not  stated),  whose 
death  was  occasioned  by  the  active  part  he  took 
in  the  American  war.  Along  with  ossified 
valves  of  the  right  auriculo-ventricular  orifice, 
there  existed  a  perforation  of  the  septum  ven- 
triculorum  large  enough  to  admit  the  extremity 
of  the  little  finger.  In  another  case,  quoted 
from  Richerand,  the  patient  aged  40,  the  per- 
foration of  the  septum  was  half  an  inch  in 
diameter. 

We  say  that  the  two  sides  of  the  heart  com- 
municate indirectly  when  the  ductus  arteriosus 
continues,  as  in  its  foetal  state,  to  convey  the 
blood  of  the  right  heart  into  the  aorta  descen- 
dens,  where  it  becomes  intermixed  with  the 
blood  of  the  left  heart.  But  it  is  very  rare  to 
find  this  condition  existing  alone,  and  when  it 
does  so  exist,  the  canal  of  communication  is 
generally  very  narrow.  More  frequently  it  is 
complicated  with  a  contracted  state  of  the  pul- 
monary artery,  the  place  of  which  it  seems  to 
supply.  In  a  case  related  by  Mr.  Howship,* 
this  vessel  constituted,  in  fact,  the  trunk  of 
the  pulmonary  artery.  The  pulmonary  artery 
proper  arose  in  its  usual  situation,  but  was 
quite  impervious  at  its  root,  though  far  beyond, 
and  terminated  in  a  cul-de-sac  beside  the  heart. 
Similar  cases  are  recorded  by  Dr.  Farre.  At 
other  times  the  ductus  arteriosus  is  emploved 
to  supply  the  place  of  the  aorta  descendens;  the 
aorta  is  perfect  only  as  far  as  the  termination 
of  its  arch,  where  it  contracts,  and  its  con- 
tinuation is  formed  by  the  ductus  arteriosus, 
through  which  the  descending  aorta  receives 
its  whole  supply  of  blood.f 

A  very  perfect  case  of  this  kind  is  quoted 
by  Dr.  PagetJ  from  Steidele.  The  aorta  and 
pulmonary  artery  arose  as  usual ;  the  aorta  was 
entirely  distributed  to  the  head  and  upper 
extremities,  while  the  pulmonary  artery,  after 
giving  off  two  branches  to  the  lungs,  con- 
tinued as  the  aorta  descendens  without  any 
communication  with  the  aorta  ascendcns. 

Malformations  of  the  valves. — A  not  un- 
important class  of  defective  malformations  in 

*  Edin.  Med.  and  Surg.  Jcu-n.  vol.  ix. 

t  See  Sir  A.  Cooper's  cases  in  Farre,  loc.  cit. 

X  Loc.  cit. 


the  heart  consists  of  imperfections  in  the  num- 
ber or  structure  of  the  valves.  The  aorta  may 
have  two  valves  only,  one  of  which  may  retain 
its  natural  form  and  size,  while  the  other  pre- 
sents the  appearance  of  having  been  formed 
by  the  fusion  of  two  valves ;  it  may  therefore 
present  one  or  more  openings  in  it,  so  as  to 
appear  somewhat  cribriform.  A  similar  con- 
dition is  met  with  in  the  pulmonary  artery, 
when  sometimes  the  three  valves  seem  as  it 
were  united  to  form  one  membrane,  which  like 
a  diaphragm  stretches  across  the  mouth  of  the 
artery,  and  is  perforated  in  the  centre  by  an 
opening  through  which  the  blood  finds  its  way 
into  the  artery.  This  narrowing  of  the  orifice 
of  the  pulmonary  artery  is  the  most  frequent 
of  the  congenital  malformations  of  the  valves  : 
we  have  already  described  it  as  a  frequent  con- 
comitant of  imperfect  septum  of  the  ventricles. 
Congenital  imperfections  of  the  mitral  and 
tricuspid  valves  are  of  very  rare  occurrence. 
The  perforated  or  cribriform  condition  which 
is  frequently  seen  affecting  these  valves,  the 
Eustachian  and  Thebesian  valves,  and  more 
rarely  the  semilunar  valves,  is  probably  the 
result  of  a  morbid  atrophy. 

Congenital  absence  of  the  pericardium. — 
Connected  with  the  malformations  by  defect 
of  developement  we  may  mention  the  con- 
genital absence  of  the  pericardium,  which, 
although  very  rare,  rests  on  too  strong  evidence 
to  admit  any  further  doubt  of  the  possibility 
of  its  occurrence.  Most  of  the  cases  related 
by  the  older  authors  weie  in  connexion  with 
displacement  of  the  heart,  and  from  the  liabi- 
lity of  mistaking  universal  adhesion  of  the 
pericardium  for  this  congenital  absence,  many 
anatomists,  among  whom  was  Haller,  denied 
that  such  a  defect  had  ever  existed. 

Dr.  Baillie*  was  the  first  of  modern  anato- 
mists who  accurately  described  a  case  of  this 
kind.  "  Upon  opening,"  he  says,  "  into 
the  cavity  of  the  chest,  in  a  man  about  forty 
years  of  age,  in  order  to  explain  at  lecture  the 
situation  of  the  thoracic  viscera,  I  was  ex- 
ceedingly surprised  to  see  the  naked  heart 
lying  on  the  left  side  of  the  chest,  and  could 
scarcely  at  first  believe  what  I  saw,  but  the 
circumstances  were  too  strong  to  keep  me  long 
in  doubt.  The  heart  was  as  bare  and  distinct 
as  it  commonly  appears  in  opening  into  the 
cavity  of  the  pericardium,  and  every  collateral 

circumstance  confirmed  the  fact   The 

heart  lay  loose  in  the  left  cavity  of  the  chest, 
unconnected  in  any  way  except  by  its  vessels ; 
was  of  a  large  size,  elongated  in  its  shape, 
and  had  its  apex  opposite  to  the  eighth  rib. 
The  right  auricle  was  obviously  in  view  in  the 
same  manner  as  when  the  pericardium  has 
been  opened,  and  the  vena  cava  superior  and 
inferior  were  clearly  observed  entering  into  it. 
The  appendage  of  the  left  auricle  w  as  as  clearly 
in  view ;  and  when  the  heart  was  inverted,  so 
as  to  have  its  apex  turned  upwards,  the  extent 
of  its  cavity  was  seen  with  the  two  pulmonary 

*  On  the  want  of  a  pericardium  in  the  human  body, 
in  Transactions  of  a  Society  for  the  Improvement 
of  Med.  and  Chir.  Knowledge,  vol.  i.  p.  91,  with 
a  plate  of  the  appearances. 


634 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


veins  of  the  left  side  entering  behind  the  ap- 
pendage. The  right  and  left  ventricles  were 
distinct,  with  the  coronary  vessels  running 
upon  them ;  and  the  aorta  and  pulmonary 
artery  were  seen  clearly  emerging  from  them." 
There  is  nothing  in  Dr.  Baillie's  description 
to  indicate  positively  whether  the  visceral  layer 
of  the  serous  pericardium  was  absent  or  not, 
although  we  may  infer  its  absence ;  what  he 
says  bearing  upon  this  subject  is  as  follows  : 
"  The  heart  was  involved  in  the  reflection  of 
the  pleura,  belonging  to  the  left  side  of  the 
chest,  which  became  its  immediate  covering, 
and  upon  making  the  slightest  incision  into  the 
substance  of  the  heart,  its  muscular  structure 
was  laid  bare,  as  in  any  common  heart  de- 
prived of  its  pericardium." 

Breschet*  has  put  on  record  a  case  in  which 
the  pericardium  was  absent,  not  altogether,  but 
in  greatest  part.  The  subject  of  it  was  a 
young  man  of  twenty-eight  years  of  age,  who 
died  in  the  Hotel  Dieu  of  an  inflammatory 
affection  of  the  intestines.  The  heart  lay  free 
under  the  left  lung  without  any  external  fibro- 
serous  envelope.  The  mediastinum  was 
formed  only  by  a  simple  serous  lamina  belong- 
ing to  the  right  pleura,  and  upon  the  left  of 
this  lay  a  rudimentary  fibrous  capsule,  attached 
above  to  the  origin  of  the  great  vessels.  The 
serous  membrane  was  altogether  absent,  but 
the  heart  was  immediately  inverted  by  a  serous 
lamella,  which  was  prolonged  from  the  left 
pleura.  In  both  this  case  and  that  of  Baillie, 
the  left  phrenic  nerve  was  displaced  and  brought 
towards  the  mesial  line  of  the  body,  and  not 
covered  by  the  serous  membrane, — an  anato- 
mical character,  which,  as  Breschet  suggests, 
may  serve  to  distinguish  congenital  absence  of 
the  pericardium  from  the  simple  adhesion  of 
that  membrane  to  the  heart.f 

II.  Malformatiom  of  the  heart  by  excess  of 
developenient. —  Plurality  of  the  heart  itself 
may  be  obviously  regarded  as  coming  under 
this  head;  but  I  am  not  aware  of  any  instance 
in  which  a  double  heart  has  been  found  in  a 
perfect  single  foetus,  nor  can  the  possibility  of 
such  an  occurrence  be  deemed  admissible. 
It  is  in  monsters  formed  by  the  junction  of  two 
that  this  double  form  of  the  heart  has  been  met 
with.  Thus,  in  one  case  referred  to  in  Bouil- 
laud's  work,  all  the  upper  parts  of  the  foetus 
were  double,  while  the  inferior  were  simple. 
There  were  two  heads,  two  necks,  quite  separate 
and  of  the  ordinary  size.  The  necks  terminated 
in  a  single  very  wide  thorax,  to  the  upper  part 
pf  which  and  between  the  insertion  of  the 
two  necks  an  arm  was  attached  in  the  vertical 
direction,  one  perfectly  formed  arm  being 
placed  on  each  side  of  the  thorax.  There  were 
four  lungs,  each  having  a  distinct  pleura,  but 
only  one  diaphragm :  there  were  also  two 
hearts  and  two  pericardia,  each  of  which  had 
two  vena  cavae  and  a  pulmonary  artery,  four 
pulmonary  veins  and  an  aorta.    The  two  aortse 

*  Mem.  sur  uu  vice  de  conformation  congenitale 
des  enveloppes  du  cceur  :  Rep.  Gen.  d'Anat.  t.  i. 
p.  212. 

f  See  references  to  other  cases  in  Otto's  Path. 
Anat.  by  South,  p.  254. 


united  at  the  lower  part  of  the  dorsal  region 
of  the  spine,  and  formed  the  artery  by  which 
the  abdominal  viscera  and  lower  extremities 
were  supplied. 

The  evidence  respecting  the  occurrence  of 
an  increase  in  the  number  of  the  parts  of  the 
heart  is  very  unsatisfactory.  The  often  quoted 
case  of  Kerkring,*  with  a  double  right  ven- 
tricle ;  one  by  Vetter,f  with  four  auricles  and 
four  ventricles,  quoted  by  Otto  ;  a  third  byChe- 
mineau,J  with  three  ventricles,  are,  if  genuine, 
the  most  remarkable  instances  on  record,  be- 
sides various  instances  in  the  lower  animals, 
especially  birds.  Andral  states  that  he  has 
seen  a  heart  with  three  auricles,  and  another 
with  four  ventricles  :  it  is  much  to  be  regretted 
that  he  has  given  no  description  of  these  sin- 
gular malformations  § 

Supernumerary  cavities,  or  septa  dividing 
the  primitive  cavities  of  the  heart,  are  the  most 
common  instances  of  excessive  developement. 
Adopting  the  arrangement  of  Andral, ||  we 
find — 1,  a  supernumerary  cavity  forming  a 
sort  of  accidental  appendage  to  one  of  the 
auricles  or  ventricles,  and  communicating  with 
the  cavity  of  the  part  to  which  it  is  attached  : 

2,  a  supernumerary  septum,  forming  an  im- 
perfect division  of  one  of  the  natural  cavities  ; 

3,  a  second  cavity,  completely  partitioned  off 
by  one  of  these  septa,  and  giving  off  super- 
numerary vessels,  which  communicate  with  the 
regular  vessels  of  the  heart.  It  appears  to  me, 
however,  to  be  very  questionable  that  all  cases 
of  supernumerary  cavities  are  the  result  of  ex- 
cessive development,  but  that,  on  the  contrary, 
they  are  sometimes  mechanically  consequent 
upon  defective  formation  in  other  parts.  At 
least  it  is  in  this  way  that  I  account  for  the  con- 
dition of  the  heart  of  a  boy,  aged  ten  years, 
which  I  examined  several  years  ago,  and  which 
has  been  described  by  my  respected  friend,  Dr. 
John  Crampton,  in  the  Transactions  of  the 
Dublin  College  of  Physicians  for  1830.  In 
this  heart  there  were  three  instances  of  defective 
developement — absence  of  the  valves  of  the 
pulmonary  artery,  an  open  foramen,  and  an 
imperfect  septum  ventriculorum.  Attached  to 
the  right  ventricle  there  was  a  supernumerary 
cavity  with  which  the  pulmonary  artery  com- 
municated. This  cavity  communicated  also 
with  the  right  ventricle,  by  an  opening  large 
enough  to  admit  the  little  finger,  and  formed 
under  the  columnse  carnese  of  the  ventricle.  The 
pulmonary  artery  was  not  only  destitute  of 
valves,  but  at  the  usual  situation  of  the  valves 
its  lining  membrane  was  puckered,  by  which 
its  orifice  was  manifestly  contracted.  The  su- 
pernumerary cavity,  in  this  instance,  was  in  all 
probability  occasioned  by  a  partial  dilatation 
of  the  infundibular  portion  of  the  right  ventri- 
cle, in  consequence  of  the  obstruction  at  the 
pulmonary  orifice. 

Increase  in  the  number  of  the  valves  of  the 
large  arteries  may  be  counted  among  the  ab- 

*  Spicil  Anat.  ohs.  69,  p.  139. 

f  Aphorism,  aus  der  Pathol.  Anat. 

f  Hist,  de  l'Acad.  des  Sc.  an.  1699. 

$  Path.  Anat.  by  Townsend,  vol.  ii.  p.  333. 

j|  Loc.  cit.j 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


635 


normal  formations  by  excess.  Thus,  four  or 
even  five  valves  are  occasionally  found  in  the 
pulmonary  artery  more  frequently  than  in  the 
aorta.  The  supernumerary  valves  are  always 
small,  and  sometimes  appear  to  have  been 
formed  at  the  expense  of  the  next  normal  one. 

Anomalous  connexion  of  the  vessels  of  the 
heart.  —  Our  space  will  only  permit  us  to 
enumerate  the  principal  observed  varieties. 
1.  The  aorta  or  pulmonary  artery,  or  both, 
appear  to  arise  equally  from  both  ventricles, 
the  septum  of  the  ventricles  being  more  or  less 
deficient.  2.  The  aorta  may  arise  from  the 
right  ventricle,  and  the  pulmonary  artery  from 
the  left,  the  veins  preserving  their  natural  posi- 
tion. 3.  The  vena  azygos  opens  into  the 
right  auricle.  4.  The  hepatic  veins  open  into 
the  right  auricle.  5.  The  ductus  arteriosus 
opens  into  the  right  ventricle.  6.  Two  superior 
vena  cava  open  into  the  right  auricle.  7. 
Very  rarely  the  right  auricle  gives  insertion 
to  one  or  more  pulmonary  veins,  and  on  the 
other  hand  the  left  auricle  receives  sometimes 
the  superior  vena  cava,  and  at  other  times  the 
inferior.  8.  Meckel  states  that  he  has  seen  the 
great  coronary  vein  of  the  heart  to  open  into 
the  left  ventricle.*  Professor  JefFray,  of  Glas- 
gow, relates  a  case  in  which  the  inferior  cava 
opened  into  the  upper  part  of  the  right  auricle, 
taking  the  course  as  well  as  the  place  of  the 
vena  azygos. 

On  displacement  or  ectopia  of  the  heart  as  a 
consequence   of  disease. — The  most  common 
cause  of  morbid  displacement  of  the  heart  is 
an  effusion  of  air  or  liquid  into  one  of  the 
pleural  cavities.    The  displacement  is  most 
manifest  when  it  follows  effusion  into  the  left 
side,  by  which  the  heart  is  pushed  over  to  the 
right,  the  degree  of  displacement  depending 
on  the  amount  of  effusion,  and  thus  alteration 
of  the  heart's   position  becomes  one  of  the 
diagnostics  of  empyema,  hydiolhorax,  pneumo- 
thorax.   In  general,  the  more  rapid  the  effusion 
the  more  certainly  will  the  displacement  be 
effected,  and  the  greater  will  be  its  extent.  In 
nine  cases  out  of  ten,  as  my  friend  Dr.  Towns- 
end  remarks,t  when  the  heart  is  removed  out  of 
its  natural  situation,  the  displacement  will  be 
found  to  have  arisen  from  empyema  or  pneumo- 
thorax ;  and  of  twenty-seven  cases  observed  by 
him,  the  heart  was  perceptibly  displaced  in 
every  instance.    On  the  other  hand,  when  the 
effusion  is  slow  and  gradual,  the  extensibility 
of  the  neighbouring  textures  is  more  completely 
brought  into  play,  and  the  displacement  of  the 
heart  is  thus  counteracted,  whence  it  happens 
that  in  cases  of  chronic  dropsical  effusions  into 
the  chest,  displacement  of  the  heart  is  not  of 
frequent  occurrence,  nor  is  it  extensive  when  it 
does  take  place.    When  the  effusion  occurs  on 
the  right  side,  the  heart  may  be  pushed  more  to 
the  left,  and  upwards,  than  is  natural,  but  to 
effect  this  a  considerable  effusion  is  necessary. 
The  first  notice  of  this  fact  is  due  to  my  able 
friend,  Dr.  Townsend,  to  whose  article  I  have 
already  referred.    In  a  case  of  pneumothorax 

*  This  enumeration  is  taken  from  Bouillaud, 
Traite  des  Maladies  du  Cceur,  t.  ii.  p.  588. 
t  Cyclop.  Pract.  Med.  vol.  ii.  p.  390. 


to  which  he  refers,  and  which  I  also  witnessed, 
the  effusion  was  on  the  right  side,  and  the 
heart  was  distinctly  seen  and  felt  pulsating 
between  the  fourth  and  fifth  ribs,  near  the  left 
axilla.  After  paracentesis,  which  was  performed 
by  the  late  Dr.  M'Dowel,  the  heart  gradually 
returned  to  its  normal  position,  as  the  displacing 
force  was  removed  by  drawing  off  the  air  and 
fluid  contained  in  the  opposite  pleura.  More- 
over, as  has  recently  been  ascertained  by  Dr. 
Stokes,  the  absorption  of  an  effusion  of  the  right 
side  will  cause  the  heart  to  be  displaced  to  that 
side,  the  pleural  cavity  being  obliterated  by 
lymph,  while  the  lung  of  the  left  side  is  en- 
larged so  as  to  aid  in  occupying  the  vacant 
space  and  pushing  the  heart  over. 

It  is  scarcely  necessary  to  observe  that  tu- 
mours forming  in  the  right  or  left  sac  of  the 
pleura  may  occasion  displacement ;  thus  aneu- 
rismal  tumours  may  push  the  heart  to  the  right, 
to  the  left  and  upwards,  or  even  forwards  and 
outwards  against  the  wall  of  the  thorax,  or 
downwards,  so  that  its  apex  will  pulsate  in  the 
epigastrium.    Of  this  last  displacement,  Dr. 
Townsend*  relates  an  example.    I  have  my- 
self observed,  some  years  ago,  a  case  where  the 
heart  was  pushed  forwards  and  outwards,  and 
as  it  were  compressed  against  the  ribs  by  an 
enormous  aneurism  of  the  thoracic  aorta ;  the 
sounds  of  the  heart  were  so  modified  by  this 
compression  as  to  lead  to  the  erroneous  diagnosis 
of  concentric  hypertrophy.  In  the  case  recorded 
by  Drs.  Graves  and  Stokes,+  the  heart  was 
pushed  upwards  and  to  the  right  side  by  an 
abdominal  aneurism,  so  as  to  pulsate  in  the  in- 
tercostal space  of  the  third  and  fourth  ribs.  Dr. 
Hope  mentions  the  displacement  to  the  left  by 
an  aneurism  of  the  ascending    aorta.  Any 
cause  which  pushes  the  diaphragm  upwards 
and  prevents  its  descent,  such  as  distension  of 
the  abdomen  by  an  enlarged  viscus,  a  tumour, 
or  an  effusion,  will  change  the  position  of  the 
heart,  so  that  its  axis  will  be  directed  horizon- 
tally ;  and  Dr.  Hope  has  remarked  that  the 
same  position  may  be  produced  by  an  adhesion 
of  the  pericardium  to  the  heart,  by  which  its 
enlargement    downwards   is    prevented.  A 
diaphragmatic  hernia  will  displace  the  heart  to 
an  extent  proportionate  to  that  of  the  visceral 
protrusion.    In  a  case  recorded  by  Drs.  Graves 
and  Stokes,  the  stomach  and  a  large  portion  of 
the  transverse  arch  of  the  colon  were  lodged  in 
the  left    cavity  of  the   thorax,  and  pushed 
the  heart  and  mediastinum  towards  the  right 
side.    When  the  lung  is  enlarged  from  dilated 
air-cells,  the  heart  may  be  displaced  :  it  may 
be  drawn  considerably  downwards  by  the  dia- 
phragm, which  yields  before  the  enlarged  lung, 
thus  increasing  the  vertical  diameter  of  the 
chest ;  or  it  may  suffer  a  slight  degree  of  lateral 
displacement,  the  mediastinum  being  pushed  to 
the  right  side  by  the  lung. J 

Dr.  Stokes  has  related  the  remarkable,  and 
so  far  as  I  know  unique  case  of  displacement, 
or  as  he  terms  it  "  dislocation,"  of  the  heart 

*  Loc.  cit. 

f  Dub.  Hosp.  Rep.  vol.  v.  p.  10. 
|  See  Dr.  Stokes's  valuable  work  on  Diseases  of 
the  Chest,  pp.  187-191. 


636 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


from  external  violence.  The  patient  was 
crushed  between  a  water-wheel  and  the  em- 
bankment on  which  the  axle  was  supported. 
Several  ribs  were  broken,  as  well  as  the  right 
clavicle  and  humerus.  The  heart,  which,  ac- 
cording to  the  statement  of  the  patient,  had 
always  occupied  its  natural  situation,  was  now 
found  beating  at  the  right  side.* 

MORBID  ALTERATIONS  OF  THE  MUSCULAR 
SUBSTANCE  OF  THE  HEART. 

1.  Inflammation  of  the  muscular  structure  of 
the  heart,  or  carditis  (the  carditis  proper  of  some 
pathologists). — The  same  anatomical  characters 
which  would  lead  us  to  pronounce  any  muscu- 
lar tissue  in  a  state  of  acute  inflammation, 
would  justify  a  similar  conclusion  respecting  the 
heart.  But  from  the  sparing  deposition  of  cel- 
lular tissue  around  this  organ  and  between  its 
fibres,  the  anatomical  phenomena  which  denote 
the  previous  existence  of  inflammation  are  not  so 
marked  in  itasinthe  muscles  of  animal  life;  and 
judging  from  the  rarity  of  these  organic  signs,  as 
well  as  from  the  unfrequent  occurrence  of  those 
symptoms  which  so  great  a  morbid  process  could 
scarcely  fail  to  produce,  we  may  reasonably 
conclude  that  active  inflammation  deeply  im- 
plicating the  carneous  fibres  of  the  heart,  and 
originating  in  them,  is  very  seldom  met  with. 

The  anatomical  characters  indicative  of  car- 
ditis are  a  dark,  almost  black,  colour  of  the 
muscular  substance,  the  fibres  of  which  have 
lost  in  a  great  measure  their  cohesive  power; 
they  are  very  compressible  and  readily  torn, 
and  consequently  cannot  be  easily  isolated  to 
any  great  extent,  although  easily  separable  en 
masse.  When  the  muscular  wall  of  either  ven- 
tricle is  pressed,  the  blood  oozes  out  from  the 
divided  vessels  on  the  cut  surface  in  much 
greater  quantity  than  usual.  In  Mr.  Stanley's 
case,  as  in  all  cases,  the  dark  colour  of  the 
fibres  "  evidently  depended  on  the  nutrient 
vessels  being  loaded  with  venous  blood."  When 
in  addition  to  these  signs  we  find  purulent  de- 
posits in  various  parts  of  the  muscular  struc- 
ture, and  moreover,  when  it  is  manifest  that  the 
internal  and  external  membranes  are  implica- 
ted, from  the  effusion  of  coagulable  lymph  on 
them  to  a  greater  or  less  extent,  no  doubt  can 
be  entertained  respecting  the  exact  nature  of 
the  lesion.  In  Mr.  Stanley's  case,  "  upon 
looking  to  the  cut  surface  exposed  in  the  section 
of  either  ventricle,  numerous  small  collections 
of  dark-coloured  pus  were  visible  in  distinct 
situations  among  the  muscular  fasciculi."  +  A 
similar  case  has  been  recorded  by  Dr.  P.  M. 
Latham,  the  anatomical  characters  of  which  ac- 
corded with  those  above  mentioned.  "  The 
whole  heart  was  found  deeply  tinged  with  dark- 
coloured  blood,  and  its  substance  softened ;  and 
here  and  there,  upon  the  section  of  both  ven- 
tricles, innumerable  small  points  of  pus  oozed 
from  among  the  muscular  fibres."  J 

Every  anatomist  must  have  noticed  how 
variable  is  the  colour  and  the  consistence  of  the 
muscular  structure  of  the  heart,  even  indepen- 

*  Med.  Gazette,  vol.  viii. 
t  Med.  Chir.  Trans,  vol.  vii. 
$  Med.  Gazette,  vol.  iii. 


dent  of  disease  of  the  lining  tissues.  The  pale, 
soft,  compressible,  flexible,  and,  to  use  a  com- 
mon word,  flabby  heart,  strongly  contrasts  with 
the  firm,  plump,  fresh-looking  elastic  one;  in 
the  former,  the  flaccid  parietes  fall  together  im- 
mediately the  cavities  are  emptied  ;  in  the  lat- 
ter, the  surfaces  retain  their  convexity,  although 
the  contents  of  the  cavities  have  been  com- 
pletely removed.  Between  these  two  extremes 
there  are  various  grades  of  colour  and  consis- 
tence, of  which  Bouillaud  particularises  three 
as  being  the  result  of  inflammation,  the  red 
softening,  the  white  or  grey,  and  the  yellow. 
The  first  is  probably  that  which  may  be  said 
unequivocally  to  follow  primary  inflammation 
of  the  muscular  texture ;  the  other  two,  how- 
ever, as  Bouillaud  admits,  occur  most  fre- 
quently in  connection  with  pericarditis :  they 
occur,  too,  as  Dr.  Copland  observes,  where  no 
sign  of  inflammation  is  manifest,  and  where 
during  life  there  had  been  no  evidence  of  car- 
diac disease  ;  in  cases  of  general  cachexia  and 
of  constitutional  disease,  attended  by  discolora- 
tion of  the  surface  of  the  body,  arising,  in  fact, 
as  Dr.  Williams  explains,  from  an  altered  state 
of  the  nutrition  of  the  organ,  owing  perhaps  to 
partial  obstructions  in  the  coronary  vessels  ra- 
ther than  to  the  immediate  influence  of  inflam- 
mation. This  last  excellent  observer  makes  the 
following  judicious  remarks  in  reference  to  this 
matter.*  "  To  judge  that  the  tissue  of  the 
heart  is  especially  diseased,  we  must  see  that  it 
differs  much  in  appearance  from  the  other 
muscles  of  the  same  subject.  You  will  find, 
on  comparing  the  same  muscles  in  different 
subjects,  a  remarkable  variety  of  colour;  and 
in  some  there  is  no  freshness  in  any  of  the 
muscles,  but  all  are  pale,  and  verging  on  a 
pinkish  drab  or  dingy  brick  colour."  Perhaps 
the  most  correct  arrangement  of  the  various  cir- 
cumstances under  which  softening  of  the  heart 
may  take  place  is  that  given  by  Andral.  1st, 
Softening  connected  with  active  hyperemia  of 
the  heart ;  2d,  softening  connected  with  anremia 
of  the  heart ;  3d,  softening  connected  with 
atrophy  of  the  heart;  4th,  softening  connected 
with  an  acute  alteration  in  the  general  nutritive 
process  (as  in  typhus) ;  5th,  softening  connected 
with  a  chronic  alteration  in  the  general  nutritive 
process  (as  in  a  variety  of  chronic  diseases) ; 
6th,  softening  which  we  are  not  yet  enabled  to 
refer  to  any  morbid  condition  of  the  heart  itself 
or  of  the  rest  of  the  system.f 

Suppuration. —  The  occurrence  of  an  abscess 
uncomplicated  with  any  other  lesion  in  the 
walls  of  the  heart,  does  not  unequivocally  de- 
note the  previous  existence  of  carditis,  although 
it  may  afford  strong  presumptive  evidence  of 
the  fact :  when,  however,  we  find  abscess,  with 
lymph  or  adhesions  of  recent  date,  we  may  rea- 
sonably infer  its  inflammatory  nature.  Dr. 
Copland  has  introduced  in  a  note  to  his  inva- 
luable and  profoundly  learned  article  on  Dis- 

*  Lectures  on  Diseases  of  the  Chest,  Med.  Gaz. 
vol.  xvi. 

t  Otto  says  that  violent  exertion  appears  as  in 
other  muscles  to  render  the  heart  easily  broken 
down  ;  thus,  for  instance,  it  is  found  very  weak  in 
hunted  deer. 


ABNORMAL  CONDITIONS  OF  THE  HEART, 


637 


eases  of  the  Heart,*  an  abstract  of  several  cases 
in  which  pus  was  found  in  the  substance  of  the 
heart.  Those  quoted  from  Corvisart,  Raikem, 
and  Simonet,  and  probably  that  from  Dr. 
Craves,f  may  be  regarded  as  examples  of  puru- 
lent formation  following  carditis,  general  or 
partial.  So  likewise  is  Laennec's  case,  in 
which,  however,  the  carditis  was  consequent 
upon  pericarditis.  There  is  no  anatomical  cha- 
racter which  will  enable  us  to  distinguish  whe- 
ther a  simple  purulent  deposit,  surrounded  by 
natural  muscular  texture,  be  inflammatory  or 
not,  for  there  is  no  reason  why  the  heart  should 
be  exempt  from  that  which  we  know  often 
occurs  in  other  muscles,  namely,  non-inflam- 
matory deposits. 

Ulceration. — As  true  carditis  seems  to  be 
generally  admitted  to  be  rare,  so  we  may  con- 
clude that  ulceration  is  equally  so.  It  is  by 
the  ulcerative  process  that  some  of  the  perfora- 
tions or  ruptures  of  the  parietes  of  the  heart 
take  place ;  it  is  probable,  however,  that  the 
great  majority  of  the  ulcerations  we  meet 
with  commence  from  the  surface,  and  result 
from  membranous  inflammation  rather  than 
from  that  of  the  muscular  substance ;  the  ulcer 
commences  on  the  surfaces,  either  in  or  imme- 
diately subjacent  to  the  internal  or  external 
membrane ;  and  as  it  burrows  deeply,  it  may 
perforate  the  muscular  wall,  and  so  destroy  the 
membrane  on  the  side  opposite  to  that  on  which 
the  ulceration  had  commenced.  Sometimes  an 
ulceration  of  this  kind  gives  rise  to  aneurismal 
tumours  or  sacs,  very  variable  in  size,  projecting 
from  that  part  of  the  cavity  which  corresponds 
to  the  artery.  It  seems  evident  that  these 
tumours  are  produced  by  the  pressure  of  the 
contained  blood  distending  the  thinned  and 
yielding  wall  of  the  heart.  We  shall  return  to 
this  subject  further  on  in  treating  of  aneurisms 
of  the  heart. 

Induration. — This  condition  of  the  muscular 
structure  of  the  heart  seems  most  probably  to 
be  a  result  of  inflammation,  especially  of  the 
chronic  kind.  It  is  generally  found  in  small 
circumscribed  portions  ;  it  may  occur  in  any 
part  of  the  heart,  and  may  even  co-exist  with 
softening  :  the  hardened  portion  has  become 
particularly  firm,  is  cut  with  difficulty,  and  when 
struck  with  the  scalpel  sounds,  as  Laennec 
says,  like  a  leather  dice-box.  It  is  harder, 
denser,  less  elastic,  and  as  regards  colour  is 
paler  than  the  hypertrophied  muscular  tissue. 

Cartilaginous  and  osseous  transformations. — 
Induration  of  the  subserous  cellular  tissue  of 
the  heart  is  in  general  the  precursor  of  many  of 
these  transformations.  This  indurated  portion 
increasing  in  thickness  gradually  assumes  the 
appearance  of  cartilage — in  this  cartilage  the 
calcareous  particles  are  deposited.  I  have  not 
been  able  to  ascertain  whether  this  so-called 
ossification  exhibits,  on  examination  by  the  mi- 
croscope, the  lamellar  arrangement  of  true  bone, 
as  osseous  transformations  of  certain  permanent 
cartilages  do,  those  of  the  thyroid  cartilage  for 
example.    These  calcareous  or  osseous  patches 

*  Diet,  of  Medicine,  part  iv.  p.  191. 

t  Lond.  Med.  and  Surg.  Journal,  vol.  vii. 


or  tumours  compress  the  subjacent  muscular 
tissue,  and  produce  atrophy  of  them,  and  ac- 
cording to  Andral,  sometimes  are  connected  by 
prolongations  of  the  same  material  with  other 
calcareous  deposits  formed  round  the  orifices. 
Many  pathologists  believe  that  these  transfor- 
mations are  the  result  of  inflammation.  I  sup- 
pose there  can  be  no  doubt  that  they  follow  an 
increased  afflux  of  blood,  and  so  they  may  be 
considered,  although  not  an  immediate,  at  least 
a  remote  effect  of  inflammation,  or  rather  of  the 
altered  nutrition  and  secretion  to  which  inflam- 
mation gave  rise. 

In  a  case  recorded  by  my  friend  Mr.  Robert 
Smith,  of  Dublin,  the  apex  of  the  left  ventricle 
was  converted  into  a  dense,  white,  firm,  car- 
tilaginous structure,  the  division  of  which  with 
a  scissors  required  the  employment  of  con- 
siderable force  ;  the  alteration  of  structure  had 
extended  to  some  of  the  carneaj  columnar.* 

Tubercles. — These  productions  are  very 
rarely  if  ever  met  with  in  the  heart.  No  re- 
liance can  be  placed  on  most  of  the  instances 
recorded,  in  consequence  of  the  imperfect  and 
unsatisfactory  descriptions  accompanying  them; 
what  appears  to  one  person  to  be  tubercular 
may  present  a  totally  different  aspect  to  another. 
Laennec  says  vaguely,  "  only  three  or  four 
times  have  I  met  with  tubercles  in  the  muscular 
substance  of  the  heart."  And  Andral  states, 
that  they  are  never  met  with  in  the  heart, 
except  when  they  likewise  occur  in  other 
muscles.  Otto  says,  "although  I  have  dis- 
sected a  great  number  of  scrofulous  men  and 
animals,  I  have  never  found  a  tubercle  on  the 
heart,  and  therefore  consider  them  very  rare." 
Dr.  Elliotsonf  mentions  a  case  in  which  there 
were  scrofulous  deposits  in  the  walls  of  the 
left  ventricle,  surrounded  by  white  and  almost 
cartilaginous  induration.  In  a  case  which  came 
under  my  own  observation,  in  a  woman  be- 
tween 50  and  60  years  of  age,  there  were  several 
white  tumours  in  the  parietes  of  the  right 
ventricle,  each  about  a  quarter  of  an  inch  in 
diameter,  of  uniform  consistence  throughout, 
nor  showing  any  disposition  to  softening  in  the 
centre. 

Scirrhus. — Equally  unsatisfactory  are  the 
reports  of  anatomists  respecting  this  alteration. 
Rullierand  Billard  relate  cases  in  which  scirrhus 
had  developed  itself  on  the  heart.  Rullier'sJ 
case  was  an  instance  of  degeneration  of  the 
whole  substance  of  the  heart  into  a  scirrhous 
mass,  which  formed  irregular  knobs  on  the  ex- 
ternal and  internal  surfaces  of  the  heart.  Bil- 
lard found  three  scirrhous  tumours  embedded  in 
the  heart  of  an  infant  only  three  days  old.§ 

Medullary  fungus,  or  encephuloid  tumours.— 
Of  these,  several  instances  are  quoted  by  Andral 
from  others,  and  he  describes  two  whicli  he 
saw  himself.||  In  the  first  of  Andral's  cases  the 
whole  of  the  walls  of  the  right  auricle  and 
ventricle  were  converted  into  a  hard,  dirty 
white  substance,  traversed  by  a  number  of 

*  Dub.  Journal,  vol.  ix.  p.  418. 
t  Lumleyan  Lectures,  p.  32. 
X  Bull,  de  la  Faculte,  1813. 
S  Malad.  des  Enfans. 
(I  Loc.  cit.  vol.  ii.  p.  346. 


638 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


reddish  lines,  and  possessing  all  the  characters 
of  encephaloid.  In  the  second  case,  the 
external  wall  of  the  right  ventricle  was  occu- 
pied by  a  tumour  extending  from  its  apex  to 
its  base,  which  projected  so  far  externally  as  to 
lead  him  to  mistake  it  for  a  supernumerary 
heart,  and  likewise  protruded  internally  into 
the  cavity  of  the  ventricle.  In  a  case  which  I  saw 
myself,  the  tumour  resembled  the  well-known 
encephaloid  or  cancerous  tumour  of  the  liver, 
being,  like  it,  raised  above  the  surrounding 
muscular  structure,  and  irregular  on  its  surface. 

Melanosis. — This  deposit  is  also  found  very 
distinctly  in  the  heart.  It  appears  in  the  form 
of  small  spots  under  the  pericardium  or  endo- 
cardium, or  as  tumours  in  the  substance  of  the 
ventricle.  In  a  specimen  in  the  Museum  of 
King's  College,  London,  the  melanotic  deposits 
are  situated,  some  beneath  the  pericardium 
covering  the  right  ventricle,  and  others  on  the 
carneae  columnae  of  the  same  cavity,immediately 
subjacent  to  the  endocardium.  Neither  Andral 
nor  Bouillaud  notices  the  occurrence  of  me- 
lanosis in  the  heart. 

Hypertrophy  of  the  heart. — When  the  walls 
of  any  of  the  heart's  cavities  experience  an  in- 
crease of  thickness,  owing  to  the  developement 
of  the  muscular  substance,  they  are  said  to  be 
in  a  state  of  hypertrophy;  and  there  is  no 
morbid  state  of  this  organ  which  is  more  fre- 
quently brought  under  the  notice  of  the  phy- 
sician than  this,  as  affecting  the  parietes  of  one 
or  more  of  its  cavities.  There  is  no  alteration 
in  the  muscular  texture  apparent  to  the  naked 
eye,  except,  perhaps,  a  slight  increase  of  the 
red  colour — the  heart  is  firm,  dense,  and 
elastic  ;  in  short,  it  presents  all  those  characters 
which  we  so  often  see  manifested  in  the  ex- 
ternal voluntary  muscles,  the  developement  of 
which  is  increased  by  frequent  use.*  Hyper- 
trophy may  affect  all  the  cavities  simultaneously, 
but  in  general  it  is  limited  to  one  or  at  most 
two  cavities.  The  left  ventricle  is  that  in  which 
it  most  frequently  occurs,  next  the  right,  and 
lastly  and  rarely  the  auricles.  Nor  does  the 
hypertrophy  affect  necessarily  the  whole  pa- 
rietes of  the  cavity,  but  sometimes  it  is 
limited  to  a  small  portion,  or  to  the  septum, 
or  to  one  or  more  of  the  carneae  columns.  In 
some  cases,  as  Andral  remarks,  the  thickening 
may  be  at  its  maximum  at  the  base  of  the 
heart,  and  diminish  gradually  towards  its  apex, 
which  sometimes  retains  its  natural  thinness, 
when  all  the  rest  of  the  parietes  are  three  or 
even  four  times  as  thick  as  natural ;  or  at  other 
times,  as  Cruveilhier  observes,  becomes  so  thin 
that  one  is  astonished  that  perforation  or  dila- 
tation of  the  heart  at  its  apex  is  not  more  com- 

*  Dr.  Williams  mentions  that  in  leucophlegmatic 
subjects  the  muscular  texture  is  soft  and  flabby 
and  of  a  duller  colour.  This  is  obviously  a  con- 
dition resulting  from  other  causes,  and  not  a  cha- 
racter of  the  hypqTtrophous  heart  as  such.  And 
the  threads  or  laminas  of  dirty  white  tissue  inter- 
mingled with  the  muscular  tissue,  described  by 
him,  seem  clearly  the  result  of  the  inflammation 
which  caused  the  concomitant  adhesion  of  the  peri- 
cardium. In  the  same  light  I  would  regard  the 
dense  fibrous  tissue  described  and  delineated  by 
Carswell. — See  Med.  Gax.  vol.  xvi.  p.  915. 


mon.  In  other  individuals  again  the  thickening 
is  equal  and  uniform  from  the  base  to  the  apex, 
which  then  loses  its  pointed  form  and  acquires  a 
rounded  shape.  Lastly,  it  sometimes  happens 
that  the  hypertrophy  is  greatest  about  midway 
between  the  apex  and  base  of  the  heart,  or  is 
even  exclusively  confined  to  that  part.  When 
the  septum  is  principally  affected,  the  capacity 
of  the  right  ventricle  is  so  diminished  that  it 
sometimes  looks  like  a  small  appendix  attached 
to  the  left  ventricle.*  When  the  hypertrophy 
affects  chiefly  or  exclusively  the  right  ventricle, 
the  apex  of  the  heart  seems  to  be  formed  by  it, 
whereas  in  the  normal  state  the  apex  belongs 
to  the  left  ventricle. 

An  hypertrophous  state  of  the  parietes  of 
all  the  cavities  not  only  affects  the  form  of  the 
heart  by  changing  it  from  the  oblong  to  the 
spherical,  but,  as  was  first  noticed  by  Dr. 
Hope,f  its  position  is  altered  ;  '*  as  the  dia- 
phragm does  not  retire  sufficiently  to  yield 
space  downwards  for  the  enlarged  organ,  it 
assumes  an  unnaturally  horizontal  position, 
encroaching  so  far  upon  the  left  cavity  of  the 
chest  as  sometimes  to  force  the  lung  upwards 
as  high  as  the  level  of  the  fourth  rib  or  even 
higher." 

BertinJ  distinguishes  three  varieties  of  hy- 
pertrophy of  the  heart.  1.  That  in  which  the 
hypertrophy  is  not  accompanied  with  any  alte- 
ration in  the  capacity  of  the  cavities  of  the 
heart — simple  hypertrophy.  2.  That  in  which 
there  is  dilatation  of  the  cavity  along  with 
the  increased  substance  of  its  walls — excentric 
hyper-trophy  or  active  aneurism  of  Corvisart. 
3.  Where  the  capacity  of  the  ventricle  is  dimi- 
nished as  if  the  walls  had  encroached  by  their 
increase  of  thickness  upon  the  cavity,  or  as 
Bouillaud  expresses  it,  as  if  the  internal  mus- 
cular layers  and  the  carneae  columnae  were  prin- 
cipally the  seat  of  hypertrophy — concentric  hy- 
pertrophy.^ Of  these  the  most  frequent  is  that 
which  is  accompanied  by  dilatation,  the  dilata- 

*  Cruveilhier  doubts  the  occurrence  of  partial 
hypertrophy  affecting  the  septum  or  one  or  more 
carneas  columnae. 

t  Cyclop,  of  Pract.  Med.  art.  Hypertrophy  of 
the  Heart. 

|  Maladies  du  Cceur. 

§  A  certain  standard  of  health  is  absolutely 
necessary  to  enable  us  to  determine  as  to  the  ex- 
istence of  disease.  With  this  view  we  transcribe 
here  the  table  of  weight  and  dimensions  drawn  up 
by  Bouillaud  as  the  average  of  health. 

In  an  adult  of  ordinary  size  and  good  constitu- 
tion the  mean  weight  =  8  to  9  oz.  ;  mean  circumfe- 
reuce  =  8  to  9  inches;  mean  of  the  longitudinal 
and  transverse  diameters  =  3i  inches  (the  latter 
generally  predominates  slightly  over  the  former)  ; 
the  mean  of  the  antero-posterior  diameter  =2  inches. 
Mean  thickness  of  the  walls  of  left  ventricle  at  the 

base  =       .  .  .  .  6  to  7  lines. 

Ditto,  right  ventricle  at  the  base  =  .  2i  lines. 
Ditto,  left  auricle  =  .  .  .14  lines. 

Ditto,  right  auricle=.  .  .  1  line. 

The  average  capacity  of  the  ventricles  is  suffi- 
cient to  contain  a  hen's  egg  (that  of  the  right  ven- 
tricle slightly  exceeding  the  left). 

For  some  useful  observations  on  this  subject,  and 
on  the  normal  weight,  bulk,  &c.  of  the  heart  in 
relation  toother  viscera,  see  Dr.  Clendinning's  Lec- 
tures in  Med.  Gazette,  vol.  xvit 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


639 


tion  in  all  probability  preceding  and  giving  rise 
to  the  hypertrophy  by  rendering  an  increased 
force  of  contraction  necessary.  Simple  hyper- 
trophy is  the  least  common,  according  to 
Bouillaud  ;  concentric  hypertrophy,  according 
to  this  physician,  is  not  rare.  Considerable 
doubt,  however,  has  been  excited  recently  by 
the  high  authority  of  M.  Cruveilhier  as  to  the 
real  existence  during  life  of  such  a  condition 
as  this.  This  anatomist  believes  the  diminished 
cavity  to  be  merely  the  result  of  a  tonic  con- 
traction of  the  muscular  wall  of  the  ventricle 
in  death.  "  The  concentrically  hypertrophied 
hearts  of  Bertin  and  Bouillaud  appear  to  me," 
he  says,  "  to  be  hearts  more  or  less  hypertro- 
phied, which  death  surprised  in  all  their  energy 
of  contractility."*  The  hearts  of  all  those 
examined  by  Cruveilhier,  who  died  by  the 
executioner,  presented  to  his  observation  to  a 
great  degree  the  double  phenomenon  of  in- 
creased thickness  of  walls  and  diminished 
cavity,  and  he  has  observed  the  same  with  per- 
sons who  died  a  violent  death. f  On  one  occa- 
sion I  was  particularly  struck  with  a  similar 
condition  of  the  heart  of  a  donkey  which  had 
been  accidentally  transfixed  by  a  large  trocar, 
whereby  the  death  of  the  animal  was  caused  in 
a  few  minutes.  The  muscular  structure  of  the 
heart  was  singularly  dense.  It  had  contracted 
at  its  apex  quite  to  a  sharp  point,  and  on  cut- 
ting into  it  the  cavity  of  the  left  ventricle  ap- 
peared almost  obliterated,  and  the  muscular 
wall  much  increased  in  thickness.  I  have 
many  times,  too,  observed  the  fact  noticed  by 
Cruveilhier,  that  the  cavity  may  be  easily  en- 
larged or  restored  to  its  natural  dimensions  by 
introducing  the  finger  and  dilating  it,  or  still 
more  easily,  if  the  heart  have  been  macerated 
in  water  for  a  short  time  previously.  This  fact 
is  further  confirmed  by  Dr.  Budd,  who  sup- 
ports the  views  of  Cruveilhier  in  an  interesting 
paper  in  the  last  volume  of  the  Medico-Chimr- 
gical  Transactions.  In  one  of  Dr.  Budd's  cases 
the  thickness  of  the  parietes  of  the  left  ventricle 
eighteen  hours  after  death  varied  from  an  inch 
to  an  inch  and  a  half,  on  a  transverse  section 
made  at  a  distance  from  the  apex  of  one-third 
of  its  length,  and  the  cavity  was  not  large 
enough  to  hold  the  second  phalanx  of  the 
thumb,  and  was  almost  filled  by  the  carnece 
columnae.  This  heart,  in  its  open  state,  was 
put  to  macerate;  no  force  ivas  applied  to  extend 
it.  At  the  end  of  some  days,  on  being  folded 
up,  it  was  found  to  have  dilated  very  conside- 
rably, so  that  the  left  ventricle  could  not  then 
be  said  to  be  smaller  than  natural.  Dr.  Budd 
argues  against  the  existence  of  the  diminished 
cavity  from  the  fact  that  of  eight  cases  collected 
by  him,  no  one  afforded  signs,  either  during 
life  or  after  death,  of  any  obstacle  to  the  circu- 
lation through  the  heart.  There  were  no  irre- 
gularity of  pulse,  no  dropsy  during  life,  no  di- 
latation of  the  right  cavities  after  death,  pheno- 
mena which,  it  may  be  said,  must  of  necessity 
be  present  if  there  be  an  obstacle  to  the  circu- 

*  Diet,  do  Med.  et  Chir.  Prat.  art.  Hypertrophic, 
t  Mr.  Jackson  and  Dr.  Budd  have  observed  this 
state  of  the  heart  in  persons  who  died  of  cholera. 


lation  in  the  heart.  It  is  impossible,  as  he 
states,  to  conceive  that  a  left  ventricle,  which 
could  scarcely  hold  an  almond,  should  offer  no 
obstacle  to  the  circulation  through  the  heart. 
Yet  Laennec  has  recorded  a  case  in  which  the 
parietes  of  the  left  ventricle  had  acquired  the 
thickness  of  from  an  inch  to  an  inch  and  a  half, 
and  the  cavity  seemed  capable  at  most  of  con- 
taining an  almond  stripped  of  its  shell.  Yet 
the  day  before  the  patient's  death  his  pulse  was 
natural,  the  breathing  perfectly  free,  "  and 
nothing,"  says  Laennec,  "  led  me  to  suppose 
that  this  man  had  a  disease  of  his  heart." 

Hypertrophy  with  dilatation. — It  is  in  this 
morbid  condition  that  the  heart  acquires  the 
greatest  increase  of  size  as  well  as  the  most 
striking  alteration  of  form.  The  cor  bovinum 
of  some  authors,  so  called  from  its  enormous 
size,  affords  an  instance  of  an  extreme  develope- 
ment  of  this  form  of  disease.  The  extent  to 
which  the  heart  may  become  enlarged  in  this 
way  is  quite  extraordinary.  Of  certain  cases 
recorded  by  Bouillaud,  in  one  the  right  ventri- 
cle was  large  enough  to  contain  a  goose's  egg, 
and  the  left,  still  larger,  the  closed  hand  of  a 
female;  in  another,  the  left  ventricle  was  simi- 
larly increased  in  capacity.  In  a  third,  the 
right  auricle  of  a  child,  aged  seven  years,  was 
so  dilated  as  to  contain  a  coagulum  as  large  as 
the  closed  hand  of  an  adult.  The  thickness  of 
the  left  ventricle  in  Bouillaud's  cases  varied 
from  7  to  14  lines,  that  of  the  right  3  to  5  lines; 
but  in  some  instances  it  was  as  considerable  as 
from  8  to  10  lines  or  11  to  16  lines.  The  weight 
of  the  heart,  in  some  instances,  trebled  the  na- 
tural ;  thus  in  one  case  of  general  hypertrophy 
the  weight  was  22  ounces,  and  others  weighed 
from  13  to  20  ounces.  The  circumference  of 
the  heart  was  often  increased  to  twelve  inches, 
the  longitudinal  diameter  five  inches,  and  the 
transverse  eight  inches.  In  a  patient  who  died 
at  the  Hotel  Dieu  in  1834,  the  heart  measured 
fifteen  inches  and  a  half  at  its  base.  Hypertro- 
phy seldom  occurs  in  the  auricles,  except  when 
accompanied  by  dilatation  :  the  musculi  pecti- 
nati  are  generally  the  seat  of  the  increased  mus- 
cular developement,  and  as  the  number  and 
developement  of  these  muscular  columns  is 
greater  in  the  right  auricle  than  in  the  left  in 
the  normal  state,  (in  the  left  they  ara  only  found 
in  the  auricular  appendage,)  the  remark  of  Dr. 
Hope  follows  almost  as  a  matter  of  course, 
namely,  that  in  the  right  auricle  hypertrophy 
proceeds  to  the  greatest  extent,  its  walls  being 
sometimes  rendered  nearly  equal  in  thickness 
to  those  of  the  right  ventricle  in  the  normal 
state. 

In  the  vast  majority  of  cases  of  this  kind  the 
produces  of  inflammatory  states  of  the  pericar- 
dium or  endocardium,  or  its  appendages,  are 
present;  in  short,  a  diseased  slate  of  the  valves 
constantly  co-exists  with  hypertrophy  and  dila- 
tation. These  conditions  of  the  cavities  are  very 
frequently  traceable  to  some  obstacle  to  the  cir- 
culation through  the  heart,  and  sometimes  it 
would  seem  that  the  valvular  disease  preceded 
and  gave  rise  to  the  hypertrophous  and  dilated 
cavity;  but  it  is  not  impossible  nor  unlikely 
that  the  valvular  disease  may  follow  the  hyper- 


640 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


trophy,  and  may  result  from  the  violence  of 
contraction  of  the  enlarged  ventricle.  Dilata- 
tion of  the  aorta  at  its  commencement  and  its 
arch  is  frequently  the  consequence  of  this  dis- 
ease in  the  left  ventricle,  and  dilatation  of  the 
pulmonary  artery  ensues  upon  it  in  the  right 
ventricle. 

Dilatation  of  the  cavities  of  the  heart. — 
"  When  the  heart  is  incapable  of  sufficiently 
expelling  its  contents,  whether  in  consequence 
of  obstruction  in  the  vessels  from  it,  of  regurgi- 
tation into  it  through  imperfect  valves,  of  want 
of  power,  of  irritability,  or  of  both,  it  becomes 
distended,  and  in  time  permanently  dilated."* 
We  have  already  described  that  kind  of  dilata- 
tion which  is  the  most  common,  namely,  that 
accompanied  by  hypertrophy ;  dilatation  also 
occurs  in  connexion  with  an  opposite  condition 
of  the  parietes,  namely,  attenuation  of  them. 
The  muscular  tissue  has  lost  its  tone,  and 
yields,  as  it  were,  without  resistance  to  the  dis- 
tending force.  It  is  laid  down  by  authors  that  a 
third  variety  of  dilatation  may  exist,  what  they 
call  simple  dilatation,  or  that  in  which,  while 
the  cavity  is  dilated,  the  parietes  are  of  their  na- 
tural size.    It  seems  to  me  impossible  that  any 
cavity  of  the  heart  can,  in  a  dilated  state,  conti- 
nue of  the  natural  thickness  withouthypertrophy, 
in  the  absence  of  which  dilatation  implies  neces- 
sarily a  diminution  in  thickness;  during  dia- 
stole the  parietes  of  the  heart's  cavities  are  thin- 
ner than  during  systole ;  what  a  contracted 
muscle  gains  in  one  dimension  it  loses  in  ano- 
ther ;  and  the  same  may  be  said  of  a  relaxed  or 
distended  muscle.  Again,  if  we  contrast  a  con- 
tracted with  a  dilated  bladder,  it  seems  evident 
that  we  cannot  inflate  the  former,  however  in- 
completely, without  producing  a  manifest  dimi- 
nution in  the  thickness  of  its  walls.    Hence  I 
infer,  that  if  the  parietes  of  any  cavity  be  per- 
fectly natural,  they  must  become  thinned  under 
the  influence  of  the  force  which  produces  the 
dilatation;  and,  on  the  other  hand,  if  we  find 
that  the  parietes  of  a  dilated  cavity  possess  the 
normal  thickness,  we  may  be  assured  that  it  is 
slightly  hypertrophous.    It  appears  then  to  be 
most  correct  to  limit  the  varieties  of  dilatation 
to  two,  that  with  hypertrophy  and  that  with 
attenuation, or  the  passive  aneurism  of  Corvisart. 

In  this  latter  form  of  dilatation,  then,  we  see 
a  manifest  alteration  of  the  muscular  tissue;  it 
is  paler,  softer,  less  resisting,  less  elastic  than 
natural.  When  the  heart  is  emptied  of  its  con- 
tents, the  walls  do  not  at  all  return  upon  them- 
selves, but  remain  flaccid ;  nor  when  cut  do 
they  show  any  disposition  to  retract;  and  it  is 
this  state  of  the  muscular  substance  which  will 
serve  best  to  enable  the  anatomist  to  distinguish 
morbid  dilatations  from  those  which  result  from 
mechanical  distension  of  the  cavity  by  a  coagu- 
lum  formed  at  the  time  of  deadi.  An  obvi- 
ously diseased  state  of  both  the  internal  and 
external  membranous  coverings  of  the  heart  is 
constantly  present  along  with  this  form  of  dila- 
tation. These  membranes  lose  their  transpa- 
rency in  several  parts,  apparently  from  some 
abnormal  deposit  subjacent  to  them :  the  white 

*  Dr.  Williams,  loc.  cit. 


spot  so  often  seen  upon  the  external  surface  of 
the  right  ventricle  is  an  almost  invariable  at- 
tendant upon  the  dilated  heart.  Dilatation 
may  affect  any  or  all  of  the  heart's  cavities ;  but 
it  is  met  with  by  far  the  most  frequently  in  the 
right  ventricle,  and  very  commonly  both  ven- 
tricles are  dilated,  in  which  case  the  right  cavity 
is  generally  more  capacious  than  the  left. 

An  extreme  case  of  dilatation  is  afforded  in 
an  example  quoted  by  Bouillaud :  "  the  right 
cavities  were  so  dilated  and  their  walls  so  at- 
tenuated, that  the  auricle  was  converted  into  a 
kind  of  transparent  membrane,  and  the  ventricle 
was  reduced  only  to  the  ordinary  thickness  of 
the  auricle.'' 

In  determining  as  to  the  degree  of  attenua- 
tion of  the  walls  which  may  accompany  any 
particular  case  of  dilatation  of  the  auricles,  the 
anatomist  must  bear  in  mind  that  even  in  the 
natural  state  the  interval  between  the  musculi 
pectinati  of  the  right  auricle  is  only  composed 
of  the  endocardium  and  pericardium,  separated 
by  a  very  fine  and  transparent  cellular  tissue, 
and  by  a  few  muscular  fibres  crossing  obliquely 
from  one  pectinate  muscle  to  the  next  one.  I 
have  twice  seen  a  perfectly  natural  right  auricle 
carefully  put  up  as  a  museum  specimen  of 
morbid  attenuation  of  the  parietes,  owing  to 
ignorance  or  forgetfulness  of  this  fact. 

Dilatation  of  the  orifices  of  the  heart. — As  a 
natural  result  of  dilated  cavities  we  meet  with 
dilated  orifices  of  the  heart,  and  the  enlarge- 
ment of  which  again  produces  in  many  cases 
insufficiency  of  the  valves.  Bouillaud  gives 
the  measurement  of  the  auriculo-ventricular 
orifice  (which  is  the  most  liable  to  dilatation) 
in  three  hearts  ;  in  one  it  measured  five  inches 
in  circumference,  and  in  another  four  inches 
three  lines,  while  in  a  third  the  dilatation  was 
stated  to  be  so  great  that  the  tricuspid  valve 
could  not  be  closed. 

Aneurism  of  the  heart. — A  diseased  state  of 
the  heart  occurs  not  unfrequently,  strongly 
analogous  to  that  which  under  the  same  name 
is  so  well  known  as  occurring  in  the  arterial 
system.  Most  of  the  varieties  too  of  arterial 
aneurism  find  their  analogues  in  the  heart : 
thus  we  have,  1.  the  aneurism  by  simple  dila- 
tation, or  true  aneurism,  resulting  from  partial 
dilatation  of  one  of  the  heart's  cavities;  2. 
the  false  aneurism  or  that  resulting  from  rup- 
ture of  one  or  more  of  the  textures  entering 
into  the  formation  of  the  heart's  parietes;  3. 
we  find  the  dissecting  aneurism  analogous  to 
that  remarkable  form  of  arterial  aneurism 
first  described  by  the  late  Mr.  Shakelton ;  4. 
not  improbably,  we  also  meet  with  what  is 
analogous  to  the  varicose  aneurism,  and  may 
be  designated  spontaneous  varicose  aneurism  of 
the  heart.  To  the  zeal  and  acuteness  of  Mr. 
Thurnam  *  morbid  anatomists  are  much  in- 
debted for  his  having  arranged,  compared,  and 
classified  a  considerable  number  of  cases  of 
aneurismal  dilatations  connected  with  the  heart, 
either  observed  by  himself,  or  preserved  and 

*  Vide  his  valuable  monograph  on  Aneurisms  of 
the  Heart  in  Med.  Chir.  Trans,  vol.  xxi.  An  ap- 
pendix containing  references  to  cases  is  added. 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


041 


recorded  by  others,  whence  lie  has  been  able 
distinctly  to  prove  the  analogies  above-men- 
tioned, and  by  which  much  light  has  been 
thrown  upon  those  forms  of  disease. 

The  partial  dilatation  of  one  of  the  cavities, 
or  true  aneurism,  is  by  far  the  most  com- 
mon of  the  varieties  above-mentioned.  In 
its  early  stage  this  disease  consists  in  little 
more  than  a  bulging  of  the  wall  of  the  ventricle 
or  auricle  in  a  certain  direction  ;  as  this  in- 
creases a  pouch  or  sac  is  formed,  which  com- 
municates with  the  heart's  cavity  by  a  more  or 
less  narrow  opening.  In  some  cases  this  sac 
does  not  extend  beyond  the  external  surface  of 
the  heart,  nor  would  it  be  detected,  were  the 
anatomist  to  content  himself  with  merely  ex- 
amining the  exterior,  it  is  as  it  were  lodged  in 
the  fleshy  substance  of  the  ventricular  paries; 
but  in  other  instances  a  tumour  is  formed  pro- 
jecting considerably  beyond  the  exterior.  As  in 
arterial  aneurisms,  the  sacs  frequently  contain 
laminated  coagula,  and,  as  might  be  expected 
(i  priori,  the  larger  the  cavity  and  the  narrower 
its  orifice  of  communication,  the  more  abun- 
dant is  this  lamellar  deposit.  One  or  more 
aneurismal  sacs  may  belong  to  the  same  cavity: 
thus,  in  fifty-two  out  of  fifty-eight  cases  col- 
lected by  Mr.  Thurnam,  only  one  aneurism 
existed  in  each  ;  but  in  four  cases  two  were 
met  with  in  each;  in  one  there  were  three, 
and  in  another  four  incipient  aneurisms.  In 
two  instances,  Mr.  Thurnam  states,  it  is  not 
improbable  that  two  sacs  which  were  originally 
distinct  had  coalesced,  so  as  to  form  a  single 
aneurism,  and  in  another  case  three  sacs  ap- 
pear to  have  united  in  this  way.  We  find  the 
aneurismal  pouches  of  all  sizes :  in  nine  of  the 
cases  referred  to  in  Mr.  Thurnam 's  memoir, 
the  size  might  be  compared  to  that  of  nuts ; 
in  twenty,  to  that  of  walnuts;  in  seven,  to 
fowl's  eggs;  in  fourteen,  to  oranges;  and  in 
nine  cases,  it  almost  or  quite  equalled  that  of 
the  healthy  heart  itself.  We  cannot  always 
satisfactorily  ascertain  what  textures  enter  into 
the  formation  of  these  sacs ;  however,  in  the 
majority  of  cases,  the  three  structures  of  which 
the  heart's  parietes  are  composed  are  found  in 
the  walls  of  these  sacs;  in  others  the  muscular 
tissue  has  disappeared,  atrophied  probably  by 
the  pressure,  and  the  wall  is  composed  only 
of  the  endocardium  and  pericardium,  and  in 
others  again  the  endocardium  is  wanting,  and 
the  muscular  fibres  and  the  pericardium  are 
the  only  component  elements.*  In  some  cases 
the  wall  of  the  sac  is  strengthened  by  an  ad- 
hesion formed  with  the  loose  layer  of  the  peri- 
cardium. 

These  aneurisms  are  always  in  connection 
with  the  left  ventricle  or  left  auricle;  very  rarely 
however  with  the  latter,  and  never  with  the 
right  cavities.  In  the  paper  already  quoted 
from,  Mr.  Thurnam  has  collected  references  to 
fifty-eight  cases  of  aneurism  of  the  left  ven- 
tricle, and  eleven  of  the  left  auricle.  All  parts 
of  the  ventricle  are  liable  to  aneurismal  dila- 
tation, but  it  occurs  most  frequently  at  the 
apex :  next  in  frequency  it  is  found  at  dif- 

*  Vide  Thurnam,  loc.  cif.  p.  219. 
VOL.  II. 


ferent  points  of  the  base;  less  frequently  still 
it  occurs  in  the  lateral  walls  at  situations  in- 
termediate to  the  two  last-named,  and  very 
rarely  it  is  met  with  in  the  interventricular 
septum. 

I  will  give  the  description  of  auricular  aneu- 
rism in  Mr.  Thurnam 's  words:  "  The  dis- 
ease would  appear, from  the  preparations  I  have 
inspected,  and  the  cases  which  have  been  re- 
corded, to  have  been  nearly  uniformly  of  the 
diffused  kind,  and  to  have  generally  involved 
the  entire  sinus  of  the  auricle.  The  dilated 
walls  of  the  cavity  are  often  thickened  and  the 
seat  of  fibro-cellular  degeneration.  The  lining 
membrane  is  opaque,  rough,  and  otherwise 
diseased,  and  in  some  cases  even  ossified,  and  is 
lined  with  fibrinous  layers,  very  similar  to  those 
met  with  in  arterial  aneurisms.  In  all  these 
cases,  the  lining  membrane  appears  to  have 
been  continued  into  the  interior  of  the  dilated 
portion,  which  consequently  merits  the  name 
true  aneurism.  Occasionally  the  dilatation  is 
confined  to  the  auricular  appendage,  which 
becomes  extensively  distended  with  lamellated 
concretions."* 

The  false  aneurism,  or  that  resulting  from 
rupture,  must  be  spoken  of  merely  as  a  pos- 
sible and  probable  occurrence.  I  know  of  no 
unequivocal  example  of  it;  but  inasmuch  as 
we  must  admit  that  partial  rupture  of  the 
heart's  wall  may  take  place,  we  cannot  deny 
the  possibility  of  the  production  of  cardiac 
aneurism  in  a  manner  similar  to  that  in  which 
arterial  false  aneurism  is  produced. 

Dr.  Hope  describes  cases,  which  Mr.  Thur- 
nam very  aptly  compares  to  "  the  dissecting 
aneurism."  In  those  cases,  Dr.  Hope  says, 
"  steatoinatous  degeneration  had  caused  the 
formation  of  a  canal  from  the  aorta  underneath 
one  of  the  sigmoid  valves  and  the  internal 
membrane  of  the  left  ventricle."  But  Mr. 
Thurnam's  explanation  seems  to  me  much 
more  likely  to  be  the  true  one.  He  supposes 
that  the  aneurisms  had  been  originally  formed 
in  the  ventricle,  and  had  subsequently  commu- 
nicated with  the  aorta,  as  a  consequence  of  the 
co-existent  disease  of  the  valves  of  that  vessel. 

The  possibility  of  the  formation  of  an  aneu- 
rism resembling  theimricose  aneurism,  has  been 
likewise  suggested  by  Mr.  Thurnam,  from  the 
occurrence  of  aneurismal  pouches  in  the  sep- 
tum ventriculorum.  If  such  an  aneurism  were 
to  burst,  it  would  establish  a  communication 
with  the  right  ventricle,  a  portion  of  the  ve- 
nous system — thus  producing  "  a  lesion  alto- 
gether analogous  to  that  which  results  from  the 
wound  of  an  artery  and  its  accompanying  vein, 
and  to  which  the  name  of  spontaneous  varicose 
aneurism  of  the  heart  is  perfectly  applicable." 

Mr.  Thurnam  mentions  a  fourth  form  of 
aneurism  which  is  not  without  its  analogue  in 
the  arterial  system,  namely,  that  in  which  the 
aneurismal  sac  is  formed  by  the  endocardium 
and  pericardium.  This  may  be  compared  with 
a  variety  of  external  aneurism  in  which  the 
lining  membrane  of  the  vessel  protrudes  through 
a  rupture  in  the  middle  tunic,  constituting  a 

*  Loc.  cit.  p.  245. 

2  v 


642 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


lesion  which  has  been  sometimes  designated  ' 
"    aiieurisma    herniosum,"     and  sometimes 
"  internal  mixed  aneurism."    This  form  of 
arterial  aneurism  has  been  described  by  Haller, 
Dubois,  Dupuytren,  and  Breschet. 

In  a  large  number  of  these  cases  of  aneu- 
rism of  the  heart,  the  pericardium  has  been  at 
some  period  or  other  of  the  disease  more  or 
less  extensively  inflamed,  and  adhesions  are 
consequently  found :  the  endocardium  like- 
wise frequently  exhibits  marks  of  inflammatory 
action,  opacities,  white  spots,  &c.  and  this 
sometimes  extends  to  the  valves.  In  some  the 
muscular  substance  in  the  neighbourhood  of 
the  sac  is  degenerated,  and  assumes  the  cellulo- 
fibrous  form.* 

Atrop/n/  of  the  heart. — The  heart,  or  a  por- 
tion of  it,  may  be  said  to  be  in  the  state  of 
atrophy,  when  its  muscular  fibres  are  pale, 
soft,  easily  torn,  inelastic,  attenuated,  so  that 
the  thickness  of  the  parietes  is  greatly  di- 
minished, and  the  pericardium  covering  the 
heart  or  the  atrophied  part  of  it,  is  shrivelled 
and  wrinkled.  When  atrophy  affects  the  whole 
heart,  that  organ  becomes  much  diminished  in 
size,  the  capacity  of  its  several  cavities  being 
proportionally  diminished  ;  and  in  some  in- 
stances the  diminution  of  the  general  size  ap- 
pears to  be  more  at  the  expense  of  the  dimen- 
sions of  the  cavities  than  of  the  thickness  of 
the  walls. 

Morbid  deposit  of  fat  on  the  heart  (fatty 
degeneration  of  some  authors).  There  is  an 
alteration  met  with  not  uncommonly  in  the 
muscles  of  animal  life,  which  is  very  often  de- 
scribed as  the  fatty  degeneration  of  muscle, 
but  which  is  in  truth  an  atrophy  of  the  mus- 
cular tissue,  and  not  at  all  a  transformation  into 
fat.  This  condition,  which  resembles  fat  only 
in  its  yellow  colour,  and  may  be  easily 
distinguished  from  it  by  its  fibrous  form,  has 
never,  I  believe,  been  met  with  in  the  heart; 
a  perfect  cessation  from  active  contraction  must 
be  essential  to  its  production;  and  as  such  a 
state  of  quiescence  cannot  occur  in  the  heart 
during  life,  this  form  of  degenerate  muscular 
tissue  is  not  found  in  that  organ.  We  do,  how- 
ever, meet  with  cases  frequently,  in  which  fat 
seems  to  take  the  place  of  the  muscular  fibres 
of  the  heart:  in  proportion  as  they  appear  to 
waste  away  the  fat  is  deposited  under  the 
serous  membrane,  until  the  muscular  parietes 
of  the  heart  are  reduced  to  a  very  thin  lamina, 
of  a  pale  colour  and  easily  torn,  between  which 
and  the  pericardium  a  thick  stratum  of  fat  is 
deposited,  so  that  a  superficial  examination 
might  lead  one  to  suppose  that  the  walls  of  the 
heart  were  wholly  converted  into  this  tissue. 
The  ventricles  are  generally,  if  not  uniformly, 
the  seat  of  this  deposit,  which  must  be  re- 
garded as  an  increase  in  the  deposit  which  is 

*  On  the  subject  of  aneurisms  of  the  heart,  the 
reader  may  consult  with  benefit  Corvisart's  clas- 
sical work,  Adams  in  Dublin  Hosp.  Rep.  vol.  iv., 
Dreschet  sur  IWneurysme  Faux  consecutif  du 
Cieur,  Rep.  Gen.  d'Anat.  t.  iii.,  Dr.  Hope's  work, 
Elliotson's  Lectures  on  Diseases  of  the  Heart,  but 
especially  the  admirable  paper  of  Mr.  Thurnam. 


found  naturally  along  the  course  of  the  coro- 
nary arteries.  It  occurs  chiefly  in  old  persons, 
and  it  is  difficult  to  say  whether  the  muscular 
atrophy  which  is  always  present  is  a  con- 
sequence of  the  fatty  deposit,  or  precedes  it. 
So  enfeebled  has  the  muscular  tissue  become 
that  persons  labouring  under  this  disease  very 
commonly  die  of  a  rupture,  or  rather  a  giving 
way,  of  the  wall  of  one  of  the  ventricles.  It 
occurs  in  persons  of  debilitated  habits,  who 
either  are  incapable  of  active  exertion  or  from 
circumstances  never  attempt  it,  and,  what  is 
remarkable,  the  subjects  of  this  disease  are 
frequently  very  emaciated :  thus  M.  Bizot* 
found  this  condition  in  fourteen  out  of  twenty- 
nine  emaciated  females.  The  disease  is  like- 
wise more  common  in  women  than  in  men ; 
and  sometimes  free  oil  is  present  in  the  blood 
in  inordinate  quantity. 

Such  I  believe  to  be  the  correct  history  of 
this  state  of  the  heart,  of  which  most  erroneous 
notions  have  been  formed,  owing  in  a  great 
measure  to  the  name  under  which  the  disease 
has  been  so  often  described.  The  description 
which  I  venture  to  offer  has  been  drawn  up 
from  several  cases  of  the  disease  in  various 
grades  of  the  deposit,  which  have  come  under 
my  observation,  and  on  comparing  this 
description  with  some  of  the  best  detailed 
cases  on  record,  it  seems  perfectly  to  con- 
sist with  the  appearances  described  in  them. 
In  Mr.  Adams'  case,f  for  instance,  "  the 
right  ventricle  seemed  composed  of  fat,  of  a 
deep  yellow  colour  through '  most  of  its  sub- 
stance. The  reticulated  lining  of  the  ventricle, 
which  here  and  there  allowed  the  fat  to  appear 
between  its  fibres,  alone  presented  any  ap- 
pearance of  muscular  structure.  The  left  ven- 
tricle was  very  thin,  and  its  whole  surface  was 
covered  with  a  layer  of  fat.  Beneath  this  the 
muscular  structure  was  not  a  line  in  thickness, 
and  was  soft,  easily  torn,  and  like  liver."  Two 
cases,  recorded  by  Mr.  R.  Smithy  presented 
the  remarkable  concomitant  of  an  oily  con- 
dition of  the  blood ;  in  one  "  numerous  glo- 
bules of  oil  were  found  floating  on  the  surface 
of  the  blood  which  escaped  from  the  divided 
vessels  ;"  and  in  the  other  "  the  surface  of  the 
blood  was  thickly  covered  with  globules  of 
limpid  oil."  In  this  last  case  the  condition 
of  the  heart's  substance  is  described  as  follows  : 
"  the  heart  was  remarkably  soft,  pale,  and 
flaccid,  its  substance  most  easily  broken,  and 
its  surface  covered  with  a  layer  of  fat  a  quarter 
of  an  inch  in  depth ;  the  parietes  of  the  ven- 
tricles were  thin."  The  anatomical  condition 
of  the  former  case  is  not  so  precisely  described 
as  to  admit  of  comparison.  The  subjects  of 
both  these  cases  were  old  women,  one  aged 
ninety,  the  other  seventy  ;  and  the  former  died 
of  rupture  of  the  left  ventricle. 

I  am  quite  unable  to  account  for  the  follow- 
ing description  of  a  case  by  Dr.  Elliotson. 
He  says,  "  I  once  saw  the  muscular  substance 
of  the  heart  completely  changed,  except  at  the 

m  Mem.  de  la  Soc.  Med.  d 'Observation, 
t  Dublin  Hosp.  Rep.  vol.  iv.  p.  396. 
\  Dublin  Journal,  vol.  ix.  p.  412. 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


043* 


svrface,  to  fat.  A  mere  layer  of  red  muscular 
structure  covered  the  internal  and  external  parts 
of  the  heart  and  the  columns  earner  :  within 
every  spot  was  fatty  matter."* 

Rupture,  of  the  heart. — A  degenerate  con- 
dition of  the  muscular  tissue  is  the  most  com- 
mon cause  of  rupture  of  the  heart:  the  states 
last  described  are  those  in  which  it  most  fre- 
quently occurs ;  they  correspond  to  the  senile 
softening  of  Blaud  :f  the  wall  literally  gives 
way  at  a  certain  point,  and  a  laceration  fre- 
quently to  a  very  trifling  extent  is  found  in  that 
situation  on  examination  after  death  :  in  some 
cases,  moreover,  several  ruptures  are  found  in 
the  wall  of  the  same  cavity,  and  sometimes 
the  rupture  is  very  extensive,  or  it  is  large  in- 
ternally and  small  externally,  or  vice  versa. 
Any  of  the  cavities  may  afford  examples  of 
this  form  of  rupture,  but  the  left  ventricle  is 
by  far  the  most  frequent  seat  of  it,  as  may  be 
understood  from  the  following  numerical  state- 
ment by  Ollivier:  "  out  of  forty-nine  cases  the 
rupture  was  seated  in  the  left  ventricle  in  thirty- 
four,  in  the  right  ventricle  in  eight,  in  the  left 
auricle  in  three,  and  in  two  cases  the  ventricles 
presented  several  ruptures.  In  these  cases 
the  apex  was  the  situation  of  the  rupture  in 
nine ;  in  the  rest  the  rupture  took  place  near 
the  base.  Rupture,  however,  may  occur  in 
a  healthy  state  of  the  organ,  from  violent  bodily 
exertion;  of  this  a  remarkable  example  was 
afforded  in  the  case  of  one  of  Whitbread's 
draymen,  who  in  attempting  to  raise  a  butt  of 
porter,  fell  dead,  from  a  large  laceration  of  the 
left  ventricle,  the  structure  of  which  was  per- 
fectly healthy.  I  had  lately  an  opportunity  of 
examining  the  preparation  of  this  heart  in  the 
Museum  of  Guy's  Hospital. 

Rupture  is  also  found  to  ensue  upon  abscess 
in  the  heart,  or  upon  ulceration  and  conse- 
quent perforation ;  it  is  sometimes  caused  by 
dilatation  of  it,  and  sometimes  by  contraction 
of  one  or  more  of  the  orifices. 

Partial  rupture  may  occur,  i.  e.  the  external 
fibres  may  be  ruptured  to  a  certain  depth, 
without  penetrating  the  cavity,  or  the  internal 
ones  may  be  similarly  torn,  the  exterior  being 
unaffected.  A  more  remarkable  kind  of  par- 
tial rupture  is  that  in  which  the  carnese  co- 
lumns or  chorda;  tendinea?  are  engaged.  Cases 
of  this  form  of  rupture  seem  to  have  been 
detailed  first  by  Corvisart,  who  attributed  the 
rupture  to  violent  efforts.  Other  cases  have 
been  subsequently  recorded  by  Cheyne,  Adams, 
and  Townsend.  In  Dr.  Cheyne's  case,  "  the 
internal  surface  of  the  left  ventricle  was  much 
inflamed,  several  irregular  excrescences  were 
attached  to  the  mitral  and  semilunar  valves. 
The  chorda?  tendinea?,  which  connected  the 
larger  portion  of  the  mitral  valve  to  the  wall 
of  the  left  ventricle,  were  torn  off  just  at  the 
point  of  their  insertion  into  the  edge  of  the 
valve;  four  of  these  ruptured  tendons  hung 
loose  into  the  ventricle."! 

*  Croonian  Lectures  on  the  Heart,  p.  32. 
t  bland,  Bibl.  Med.  an.  1820. 
X  Dublin  Hosp.  Rep.  vol.  iv.    On  the  subject  of 
rupture  of  the  heart  the  reader  may  consult  Olli- 


MoRBID    STATES   OF   THE    MEMBRANES  OF 
THE  HEART. 

I.  Morbid  slates  of  the  pericardium. — 1 .  Pe- 
ricarditis. The  morbid  changes  of  the  serous 
pericardium  which  most  frequently  come  under 
the  notice  of  the  anatomist,  are  those 
which  are  consequent  upon  inflammation. 
What  the  alterations  are  which  indicate  the 
first  onset  of  inflammatory  action  it  is  not  easy 
to  determine  precisely,  as  the  opportunities  of 
inspecting  the  parts  in  this  early  stage  of  peri- 
carditis are  extremely  rare.  The  following, 
however,  may  be  stated  as  indicative  of  the 
earliest  period  of  pericarditis.  The  natural 
exhalation  becomes  diminished  or  totally 
suppressed,  and  consequently  the  surfaces  of  the 
membrane  do  not  present  their  usual  moist 
appearance ;  the  visceral  layer  of  the  pericar- 
dium is  not  so  transparent  as  in  the  natural 
state,  and  several  red  points,  which  to  the  naked 
eye  appear  like  extravasations  of  blood,  are 
manifested  on  a  considerable  portion  of  the 
membrane.  These  spots,  however,  are  not 
extravasations,  but  when  examined  with  a  lens, 
they  are  seen  to  be  produced  by  a  close  net- 
work of  extremely  minute  capillary  vessels ; 
as  inflammation  advances  these  spots  increase 
in  number,  neighbouring  ones  coalesce,  a  more 
or  less  diffused  redness  is  produced,  as  well 
from  vessels  subjacent  to,  as  in  the  membrane, 
the  membrane  becomes  less  and  less  transparent, 
and  now  an  exudation  is  distinctly  formed  on 
its  surface  of  a  very  soft  semifluid  material  (co- 
agulable  lymph),  which,  on  looking  carefully 
along  the  inflamed  surface,  is  seen  to  be  de- 
veloped in  minute  granules.  The  further  pro- 
gress of  the  disease  is  characterised  by  the 
increased  deposition  of  this  plastic  material, 
and  the  effusion  of  a  straw-coloured  serous 
fluid  into  the  bag  of  the  pericardium.  These 
morbid  changes,  of  course,  vary  in  extent ;  but 
it  is  not  uncommon  to  find  them  extending 
over  the  greatest  part  or  even  the  whole  heart, 
so  that  in  some  cases  a  second  complete  enve- 
lope is  formed  for  the  heart  between  the  visce- 
ral and  parietal  layers  of  the  serous  pericar- 
dium ;  on  the  other  hand  a  very  circumscribed 
spot  may  be  occupied  by  these  changes,  not  ex- 
ceeding a  half-crown  or  a  crown  piece  in  circumfe- 
rence ;  but  we  seldom  or  never  have  opportu- 
nities of  seeing  the  disease  on  this  limited 
scale  in  so  early  a  stage,  and  judge  of  its 
occurrence  only  from  the  existence  of  alterations 
which  may  justly  be  regarded  as  its  sequela?. 

Certain  varieties  are  observed  as  regards  the 
form  assumed  by  the  lymph,  and  the  quantity  of 
the  fluid  effused  in  this  disease.  The  lymph 
varies  in  its  characters  ;  almost  always  depo- 
sited in  a  membranous  form,  it  is  sometimes 
quite  smooth  and  uniform  on  its  free  sur- 
face ;  at  other  times  it  is  rough,  and  hangs  in 
flocculi  into  the  fluid  contained  in  the  sac  of 
the  pericardium  ;  again  it  presents  a  reticulate 
appearance,  compared  by  Corvisart,  Laennec, 
and  Bertin,  to  the  inner  surface  of  the  second 

vicr's  article  (Cceur  Rupture)  in  Diet,  de  Med., 
Townsend  in  Cyclop.  Pract.  Med.  vol.  iv.  p.  630., 
and  Bouillaud's  work. 

2  u  2 


644 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


stomach  of  the  calf,  or,  as  Laennec  suggested, 
to  the  appearance  produced  by  quickly  se- 
parating two  slabs  of  marble  which  have  been 
applied  together,  with  a  small  quantity  of 
butter  or  some  similar  substance  between  them. 
The  depth  of  the  depressions  iri  this  false 
membrane  varies  with  the  thickness  of  the 
membrane  itself.  Shortly  after  its  deposition 
the  lymph  is  very  tender  and  easily  torn,  but 
when  it  has  been  some  time  deposited,  it  ac- 
quires a  considerable  power  of  resistance.  The 
effused  fluid  in  pericarditis  varies  likewise  in 
quality  and  quantity.  In  some  cases  it  is 
whey-coloured,  with  flocculi  of  lymph  floating 
in  it ;  in  others  it  is  of  a  yellowish  colour,  ap- 
proaching that  of  pus,  and  in  some  degree  of 
the  same  consistence :  sometimes  it  is  of  a 
brownish  colour.  When  it  is  in  very  small 
quantity  it  is  less  turbid  ;  when  in  large  quan- 
tity it  resembles  whey.  In  some  cases  the 
quantity  is  very  considerable.  It  may  be  said 
to  vary  from  a  few  ounces  to  more  than  a  pint ; 
but  in  some  extreme  cases  it  goes  even  far  be- 
yond this;  thus  Corvisart  mentions  a  case  in 
which  the  effused  fluid  amounted  to  eight 
pounds,  and  in  one  described  by  Bertin  the 
distended  pericardium  formed  a  bag  seven  or 
eight  inches  broad,  five  deep,  and  ten  or  eleven 
in  height.  Sometimes  the  effusion  cannot  be 
distinguished  from  pus. 

The  coagulable  lymph  is  effused  not  only  on 
the  free  surface  of  the  visceral  layer  of  the  pe- 
ricardium, but  likewise  on  that  of  the  parietal 
layer.  That  which  is  effused  upon  this  latter 
layer  is,  however,  often  much  thinner  and 
more  delicate.  These  two  deposits  of  lymph 
are  continuous  with  each  other  at  the  reflection 
of  the  serous  pericardium  from  the  great  vessels 
on  to  the  muscular  fibres.  When  the  effused  fluid 
hasbeen  lenioved  by  absorption,  the  two  pseudo- 
membranes  being  brought  into  apposition  with 
each  other,  areas  it  were  glued  together;  they 
become  organised  by  new  vessels  shooting  into 
them  from  the  cardiac  vessels,  and  at  length 
they  assume  the  form  of  cellular  tissue.  The 
•cavity  of  the  pericardium  thus  becomes  oblite- 
rated by  the  development  of  this  new  cellular 
tissue.  The  adhesions  thus  formed  are  more 
or  less  extensive  according  to  the  extent  of  the 
primitive  inflammation,  so  that  in  some  cases 
the  pericardium  is  universally  adherent  to  the 
heart ;  in  others  the  adhesion  is  circumscribed 
within  very  narrow  limits ;  in  this  latter  case 
the  new  cellular  membrane  is  often  of  conside- 
rable length,  inasmuch  as  the  spots  to  which  it 
adheres  on  the  opposed  layers  of  serous  mem- 
brane do  not  at  all  correspond ;  but  when  the 
adhesion  is  extensive,  the  connecting  cellular 
membrane  is  generally  short  and  close,  so  much 
so  in  some  cases  that  the  pericardium  and  heart 
appear  to  be  completely  identified.  The  mus- 
cular substance  subjacent  to  the  inflamed  peri- 
cardium sometimes  appeals  to  participate  in 
the  inflammatory  process,  acquires  a  greater 
hue  of  redness  than  is  natural,  and  becomes 
softer,  and  loses  to  a  greater  or  less  degree  its 
cohesive  power. 

Such  is  the  ordinary  course  and  termination 
of  pericarditis.    Every  museum  contains  many 


specimens  illustrative  of  the  different  stages  of 
this  disease.  The  cellular  adhesion  which  fills 
up  the  pericardial  cavity  occasionally  exhibits 
further  alterations.  Sometimes  we  find  it  infil- 
trated with  serum, and  quite anasarcous;  at  other 
times  a  sero-purulent  or  purulent  fluid  is  effused 
into  it.  It  becomes  condensed,  fibrous  in  its 
character;  or  cartilaginous  or  fibro-cartilaginous 
or  even  osseous  plates  are  formed  in  it,  which 
sometimes  are  of  so  large  a  size  that  the  heart 
appears  as  if  enveloped  in  an  osseous  case. 
This  cartilaginous  or  osseous  deposit,  however, 
sometimes  takes  place  in  the  fibrous  pericardium. 
Dr.  Hodgkin  mentions  a  case  of  osseous  trans- 
formation so  extensive  that  the  osseous  plate 
occupied  a  large  portion  of  the  base  of  the 
heart,  where  it  formed  a  complete  bony  ring, 
the  apex  of  the  heart,  however,  being;  left  at 
liberty.  A  somewhat  similar  case  is  recorded 
by  my  friend  Mr.  Smith.  "  The  pericardium  was 
united  to  the  surface  of  the  heart  by  close  and 
old  adhesions,  and  around  the  base  of  the 
organ  bony  matter  was  deposited  in  considera- 
ble quantity,  apparently  between  the  two  serous 
layers  of  the  pericardium ;  it  formed  an  osseous 
belt  surrounding  nearly  theentireofthebase  ofthe 
heart  ;  its  surface  flat  and  rough,  its  margin 
irregular  and  waving,  and  its  average  breadth 
about  one  inch.  This  bony  girdle  penetrated 
into  the  substance  of  the  ventricles,  and  reached 
in  some  parts  almost  to  the  lining  membrane  of  the 
latter."*  In  Mr.  Burns'  case  the  whole  extent 
of  the  pericardium  covering  the  ventricles,  and 
the  ventricles  themselves,  except  about  a  cubic 
inch  at  the  apex  of  the  heart,  were  ossified  and 
firm  as  the  skull. 

White  spot  on  the  heart. — -There  is  no  ap- 
pearance with  which  anatomists  are  more 
familiar  than  the  white  spots  on  the  heart.  A 
single  portion  of  white  opaque,  or  nearly 
opaque  membrane,  situated  on  the  anterior  part 
of  the  right  ventricle  nearer  its  apex  than  its 
base,  and  varying  in  circumference  from  that  of 
a  shilling  to  that  of  a  half-crown,  as  thick  as 
the  pericardium  itself  and  sometimes  conside- 
rably thicker,  constitutes  what  I  have  most  fre- 
quently seen.  They  may  be  found,  however,  oc- 
casionally on  the  posterior  surface  as  well  as  the 
anterior,  on  the  left  side  as  well  as  the  right, 
on  the  auricles  as  well  as  the  ventricles.  On 
careful  examination,  it  is  evident  that  the  opa- 
city is  occasioned  by  an  adventitious  deposit. 
This  deposit,  in  a  great  number  of  the  cases 
in  which  I  have  examined  it,  consisted  of  a 
thin  lamina  of  condensed  cellular  membrane 
adherent  to  the  free  surface  of  the  visceral 
layer  of  the  pericardium,  which  could  easily  be 
dissected  off,  and  which  I  have  often  peeled  off 
with  my  fingers,  leaving  the  pericardium  appa- 
rently as  if  no  deposit  had  been  found  there. 
Dr.  Baillie,  and  more  recently  Laennec  and 
Louis,  testify  to  the  facility  with  which  it 
may  be  dissected  off.  Others,  however,  affirm 
that  the  deposit  is  most  frequently  under  the 
serous  covering  of  the  heart,  and  consequently 
in  the  subserous  cellular  tissue  by  which  that 
layer  is  connected  to  the  heart.  Corvisart 

*  Dub.  Journ,  vol.  ix.  p.  419. 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


645 


maintains  this  opinion  exclusively,  and  Dr. 
Hodgkin  states  his  belief  that  in  by  far  the 
greater  number  of  eases  these  patches  depend 
on  a  deposit  on  the  attached  surface.  This 
writer  adds — "  From  the  circumstance  of  their 
being  often  found  immediately  under  the  ster- 
num, and  from  their  being  occasionally  met 
with  on  other  parts  of  the  heart,  to  which  a  firm 
and  resisting  body  has  been  unusually  opposed  ; 
as  for  example,  when  a  bony  deposit  has  taken 
place  beneath  the  reflected  pericardium,  or 
when  an  uneven  and  remarkably  indurated 
liver  has,  even  through  the  diaphragm,  presented 
an  unequal  pressure  against  a  particular  part  of 
the  heart,  I  have  thought  it  probable  that  such 
pressure,  aided  by  the  movements  of  the  heart 
itself,  may  have  led  to  the  production  of  these 
spots.  These  formations  may  certainly  take 
place  at  a  very  early  period  of  life.  I  have 
met  with  one  rather  loose  and  thick,  but  in 
other  respects  perfectly  resembling  those  found 
in  the  adult,  on  the  right  ventricle  of  a  child 
only  ten  weeks  old.  Similar  thickening  of  the 
close  pericardium  sometimes  marks  the  course 
of  the  coronary  arteries  and  their  brandies;  and 
this  circumstance  amongst  others  tends  to  con- 
firm the  idea  which  I  entertain  as  to  its  mode 
of  formation."* 

Mr.  T.  VV.  King,  in  an  Essay  on  this  subject 
in  the  sixth  number  of  Guy's  Hospital  Reports, 
records  a  very  remarkable  example  of  the  opa- 
city. The  patch,  "  a  uniform  whitish  thicken- 
ing of  the  close  pericardium,"  nearly  equalled 
in  extent  the  anterior  surface  of  the  right  ven- 
tricle, and  was  extended  over  the  anterior  sur- 
face of  the  pulmonary  artery  as  far  as  its  bifur- 
cation. Two  similar  patches  were  found  on 
the  under  surface  of  the  ventricle.  Mr.  King 
inclines  to  the  opinion  that  this  deposit  is 
seated  in  the  proper  tissue  of  the  serous  mem- 
brane, and  considers  it  always  inflammatory 
and  pretty  constantly  the  effect  of  friction  and 
irritation.  "  The  situation  of  these  patches," 
observes  Mr.  King,"  whenever  they  occur,  im- 
plies to  my  min  d  a  egree  of  attrition  at  the 
part  more  than  belongs  to  the  pericardium  ge- 
nerally. They  are  found  on  the  surface  of  the 
right  auricle  almost  as  frequently  as  on  the  ven- 
tricle, but  not  in  so  morbid  a  form  ;  and  much 
more  divided,  even  minute,  and  often  clustered 
like  the  rippling  of  the  sand  at  ebb-tide.  One 
is  not  unfrequently  seen  along  the  anterior 
face  of  the  great  pulmonary  artery.  All  these 
relate  to  the  right  side  of  the  heart,  which  all 
pathologists  are  aware  is  often,  and  more  than 
the  left,  the  subject  of  distensions.  The 
patches  may  occasionally,  perhaps,  be  seen  on 
any  part  of  the  close  pericardium.  I  have 
seen  them  behind  the  left  pulmonary  veins  ; 
but,  omitting  this  instance,  the  next  most  com- 
mon appearance  of  the  kind  is  that  of  length- 
ened, narrow,  winding,  and  even  branching 
lines  immediately  over  the  great  vessels  of  the 
ventricles  whenever  they  are  the  subject  of  con- 
siderable dilatation.  Here,  also,  we  have  evi- 
dence of  a  disproportionate  space  of  attrition, 
resulting  from  undue  prominence." 

*Lect.  on  Morb.  iinat.  of  serous  membranes,  p.  98. 


I  am  not  aware  of  any  well-authenticated 
instance  of  ulceration  or  gangrene  of  the  peri- 
cardium. In  cases  of  ulcerative  perforation  of 
the  heart,  it  may  be  said,  however,  that  the  pe- 
ricardium ulcerates  as  the  other  parts  do. 

Tubercular  formations. — Tubercles,  whether 
cancerous,  melanotic,  or  scrofulous,  are  formed 
subjacent  to  either  serous  layer  of  the  pericar- 
dium ;  sometimes,  and  most  frequently  they 
are  deposited  between  the  visceral  layer  and  the 
heart,  or  they  may  be  found  between  the  fibrous 
pericardium  and  the  parietal  aspect  of  the  se- 
rous layer. 

Cysts. — The  serous  cysts  which  are  described 
as  occurring  in  the  heart  are  sometimes  formed 
immediately  subjacent  to  the  serous  membrane, 
and  project  into  the  pericardial  sac.  Accord- 
ing to  Andral  they  occur  most  frequently  in 
this  situation.  Similar  cysts  have  been  found 
between  the  fibrous  pericardium  and  its  serous 
lining. 

Hi/drops  pericardii  or  hydropericardium.— 
This  disease  consists  in  an  undue  accumulation 
of  fluid  in  the  sac  of  the  pericardium.  The 
fluid  is  either  simply  serous,  of  yellowish  cha- 
racter, or  it  may  be  of  a  brownish  or  reddish 
hue.  In  quantity  it  rarely  exceeds  two  pints. 
The  effusion  is  not  generally  attended  with  any 
evident  morbid  change  either  of  the  heart  or  its 
membranes,  excepting  that  in  cases  of  some 
standing,  the  heart  seems  somewhat  atrophied, 
and  the  pericardium  has  lost  its  perfect  trans- 
parency. 

Pneumopericardium. — The  presence  of  air  in 
the  pericardium,  as  the  effect  of  morbid  action 
during  life,  must  be  very  rare.  Laennec,  how- 
ever, speaks  very  confidently  of  its  existence. 
"  Sometimes,"  he  says,  "  the  air  is  combined 
with  a  liquid,  and  this  is  by  much  the  most 
frequent  case  ;  at  other  times  the  pericardium 
is  distended  by  air  alone."  Could  the  cases  of 
dry  pericardium  related  by  Baillie  have  been 
produced  by  the  developementofairin  its  cavity  ? 

Morbid  states  of  the  endocardium. — 1.  En- 
docarditis. The  lining  membrane  of  the  heart 
is  so  similar  in  its  structure  and  properties  to 
the  pericardium,  that  their  morbid  states  are 
very  similar  likewise.  The  constant  contact  of 
the  blood  with  the  former  membrane  serves, 
however,  to  modify  considerably  the  anatomical 
characters  of  disease  in  it.  We  want,  I  think, 
satisfactory  proofs  of  the  changes  induced  by 
endocarditis  in  its  earliest  stage;  these  changes 
are  described  to  be,  redness  of  the  membrane, 
with  a  more  or  less  thickened  or  swollen  condi- 
tion of  it;  but  the  redness  is  not  the  result  of 
capillary  injection,  but  seems  to  be  a  stain  on 
the  membrane,  the  result  of  contact  with  the 
blood.  The  stain  is  not  merely  superficial,  but 
has  sunk  into  the  substance  of  the  tissue,  and 
it  cannot  consequently  be  washed  off. 

The  lining  membrane  of  the  heart  is  often 
found  stained  of  a  red  colour  as  a  post-mortem 
result;  and  this  is  invariably  the  case  in  hearts 
examined  after  putrefaction  has  commenced. 
The  blood  contained  in  the  heart  has  begun  to 
alter,  various  gases  are  given  out,  and  the  inter- 
nal membrane  more  readily  imbibes  the  colour- 
ing matter  that  is  brought  in  contact  with  it. 


646 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


Can  this  redness  be  distinguished  from  that 
which  is  consequent  upon  inflammation  ?  It 
seems  to  me  that  there  is  no  anutumical  charac- 
ter by  which  the  true  nature  of  the  discoloration 
can  be  proved.    The  anatomist  must  be  guided 
in  coming  to  a  conclusion  upon  the  question 
by  concomitant  circumstances,  of  which  the 
time  which  has  elapsed  after  death,  the  quan- 
tity and  quality  of  the  blood  in  the  heart,  and 
the  state  of  the  other  organs  or  textures  of  the 
body,  are  the  most  important.    If  the  examina- 
tion has  been  made  soon  after  death,  that  is, 
within  twenty-four  hours,  if  the  blood  in  the 
heart  presents  no  undue  predominance  of  co- 
louring matter,  nor  has  undergone  any  decom- 
position, and  if  the  other  tissues  retain  their  na- 
tural state,  and  show  no  unusual  tendency  to 
putrefaction,  the  redness  may  be  inferred  to  be 
morbid  and  inflammatory;  but  this  inference  is 
confirmed  with  the  utmost  degree  of  certainty, 
if  the  redness  is  accompanied  by  an  effusion  of 
coagulable  lymph  or  of  pus,  and  by  an  unequi- 
vocal thickening  or  swelling  of  the  endocardium 
itself;  sometimes,  also,  as  Bouillaud  remarks, 
the  adhesion  of  clots,  resembling  the  buffy 
coat   of  blood,  are  among   the  anatomical 
signs   of   inflamed   endocardium.     The  in- 
flamed endocardium  is,  according  to  Bouil- 
laud, more  easily  detached  from  the  internal 
surface  of  the  heart,  owing  in  all  probability  to 
the  subjacent  cellular  tissue  having  lost  its 
force  of  cohesion,  and  become  fragile. 

Lymph  effused  on  the  endocardium  does  not 
generally  take  the  laminated  form  as  in  pericar- 
ditis, nor  do  we  find  it  covering  an  extensive 
surface,  as  in  that  disease.  Small  patches  of 
membranous  lymph  are  sometimes  met  with 
here  and  there,  either  on  the  surface  of  the 
valves  or  over  some  part  of  one  of  the  cavities; 
at  other  times  it  assumes  a  granular  or  warty 
form,  or  it  projects  in  papilliform  or  conical  or 
globular  masses  from  the  surface  of  the  valve. 
Thus  are  formed  the  vegetations  which  are 
among  the  most  frequent  valvular  diseases,  and 
which  offer  the  greatest  impediments  to  the 
adequate  action  of  the  valves.  When  examined 
recently  after  their  formation,  they  present  all 
the  characters  of  the  album ino-fibiinous  exuda- 
tions of  serous  membranes,  their  form  being 
determined  by  the  frequent  changes  of  relation 
which  the  inflamed  surface  undergoes  in  the 
heart's  action,  as  well  as  by  the  current  of 
blood  from  the  heart  continually  flowing  over 
it. 

The  further  progress  of  inflammation  of  the 
endocardium  induces  thickening  of  the  mem- 
brane or  of  the  valves,  organization  of  the  effu- 
sed lymph,  which  thus  becomes  more  firmly 
adherent  to  the  surface  on  which  it  had  arisen, 
and  induration  of  the  membrane  from  cartilagi- 
nous or  calcareous  deposits,  which  however  are 
generally  met  with  within  the  fold  of  membrane 
constituting  the  valves,  and  more  intimately 
connected  with  the  interposed  fibrous  than  with 
the  serous  membrane. 

When  inflammation  of  the  folds  of  endocar- 
dium forming  the  valves  runs  its  course  with 
great  rapidity,  it  may  induce  destruction  of 
them  to  a  greater  or  less  extent.  Softening, 


ulceration,  and  rupture  of  the  affected  valve  are 
very  speedily  produced.  "  The  ruptured  and 
ulcerated  portions,"  to  borrow  Dr.  C.  J.  Wil- 
liams's description,  "  are  found  loaded  with 
ragged,  soft,  fragile  vegetations,  more  or  less 
tinged  with  blood,  and  these  are  also  some- 
times seen  adhering  to  adjacent  parts  where  the 
endocardium  is  entire.  The  remaining  parts  of 
the  valves  are  much  thickened  and  opaque  yel- 
lowish white,  with  a  pink  hue;  and  pink  patches 
are  often  seen  in  the  aorta  with  atheromatous 
thickening."  Sometimes  a  valve  is  perforated 
in  its  centre  by  ulceration,  and  the  circumfe- 
rence of  the  perforation  is  surrounded  by  warty 
vegetations. 

It  is  well  known  that  the  endocardium  of 
the  left  side  is  much  more  liable  to  disease  than 
that  of  the  right,  whether  as  regards  the  valvu- 
lar portion  of  it  or  that  which  lines  the  interior 
of  the  heart.  But  the  views  of  Bichat  and 
others,  who  denied  the  occurrence  of  disease 
on  the  right  side,  have  been  abundantly  refuted 
by  modern  observations. 

Chronic  valvular  diseases. — Chronic  endocar- 
ditis affects  the  valves  of  the  heart  in  such  a 
manner  as  in  all  cases  to  occasion  more  or  less 
obstacle  to  the  flow  of  the  blood  from  the  ven- 
tricle or  auricle.  Sometimes,  however,  the 
disease  is  not  of  a  kind  to  interfere  with  the 
valvular  action  and  to  permit  regurgitation;  but 
at  other  times  the  disease  has  gone  so  far  in 
one  or  more  of  the  valves  as  to  prevent  its  con- 
tributing to  the  perfect  closure  of  the  orifice, 
and  consequently  to  destroy  the  power  of  the 
valves  to  oppose  regurgitation.  Hence  the 
subdivision  proposed  by  Dr.  Williams,  for  val- 
vular diseases,  into  those  which  more  or  less 
obstruct  the  current  of  the  blood  in  its  proper 
channel,  or  the  obstructive,  and  those  which 
permit  it  to  pass  in  the  reversed  direction,  or  the 
regurgitant.  Thickening  of  a  valve,  so  as  to 
prevent  its  complete  apposition  to  the  internal 
surface  of  the  artery  or  of  the  ventricle,  will  oc- 
casion obstruction,  the  degree  of  which  will 
depend  on  the  degree  of  perfection  of  apposi- 
tion with  which  the  valve  may  be  applied  to 
the  neighbouring  surface;  on  the  other  hand, 
the  degree  to  which  regurgitation  is  permitted 
will  depend  upon  the  degree  of  induration  of 
the  valve,  and  the  want  of  extensibility  which 
it  manifests. 

Thickening  of  the  edges  of  the  valves  is 
among  their  most  common  diseased  states;  the 
attached  margin  or  base  of  the  valve  is  also  very 
frequently  the  seat  of  thickening,  and  in  both 
these  situations  the  fibrous  tissue  seems  to  be 
engaged  principally  in  the  disease.  The  inter- 
vening portion  is  generally  affected  as  a  conse- 
quence of  the  extension  of  the  disease  from 
these  margins.  In  such  cases  the  thickening 
arises  from  a  deposit  between  the  layers  of  the 
fold  forming  the  valve;  in  other  cases  the  thick- 
ening is  produced  by  a  deposit  upon  the  surface 
of  the  valve.  On  the  aortic  valves  this  deposit, 
when  on  the  ventricular  surface,  is  apt  to  assume 
the  form  of  two  crescents  corresponding  in  po- 
sition as  well  as  form  to  the  two  crescentic  por- 
tions of  fibrous  tissue  within  the  fold  of  mem- 
brane by  which  the  vnUe  is  formed.    This  fact 


ABNORMAL  CONDITIONS  OF  THE  HEART. 


647 


was,  I  believe,  first  pointed  out  by  Dr. 
Watson. 

Ossification  most  commonly  manifests  itself 
in  the  fibrous  zones  which  surround  the  heart's 
orifices,  and  therefore  it  is  chiefly  to  be  found 
at  the  bases  of  the  valves ;  but  it  likewise  ex- 
tends towards  their  free  margin  ;  and  it  too  is 
apt  to  be  developed  in  the  double  crescentic 
form  in  the  aortic  valves.  Sometimes  the  ossi- 
fication appears  to  involve  principally  the  mar- 
gin of  the  valve  in  whole  or  in  part,  and  this 
occurs  much  more  frequently  in  the  semilunar 
than  in  the  auriculo-ventricular  valves.  Osseous 
deposits  in  the  valves  are  either  in  the  form  of 
thin  calcareous  lamina?  or  spiculoe,  small  round- 
ed points,  or  large  masses  more  or  less  rounded, 
and  often  projecting  to  a  considerable  extent 
beyond  the  surface  of  the  valve. 

The  effect  which  the  developement  of  these 
new  deposits  on  or  in  the  valves  has  upon  their 
size  and  form,  as  well  as  upon  the  size  and  form 
of  the  openings  which  the  valves  surround,  is 
very  various  and  very  interesting  to  the  patho- 
logist. The  almost  invariable  alteration  which 
they  produce  in  the  size  of  the  valve  is  to 
shorten  it  or  dimiwsh  it  in  depth  ;  the  valve 
becomes  corrugated\  its  free  margin  thickened, 
or  folded  in  the  direction  of  the  current,  or  in 
an  opposite  direction,  the  whole  valve  present- 
ing a  curled  appearance.  The  orifices  are 
always  more  or  less,  diminished  in  size  when 
one  or  more  valves  have  acquired  this  rigid, 
inelastic,  and  contracted  form ;  the  diminution 
is  produced  by  the  valve  or  valves  always  pro- 
jecting more  or  less  into  the  orifice ;  but  the 
greatest  degree  of  narrowing  of  the  aperture  is 
occasioned  by  the  adhesion  of  two  or  more 
valves  at  their  free  margins ;  and  in  this  way, 
as  may  be  readily  conceived,  an  orifice  be- 
comes sometimes  almost  completely  obliterated. 
The  same  causes  change  the  shape  of  the  orifi- 
ces, and  consequently  we  find  altered  size  and 
shape  constantly  going  together.  It  is  in  the 
left  auriculo-ventricular  opening  that  these 
changes  are  most  commonly  seen ;  they  rarely 
occur  to  so  great  an  extent  in  the  aortic  orifice, 
and  seldom  at  all  in  the  apertures  of  the  right 
heart.  My  friend,  Mr.  Adams,  has  made  some 
most  valuable  remarks  upon  the  contracted  au- 
riculo-ventricular orifice  of  the  left  side,  in  his 
very  valuable  paper  on  diseases  of  the  heart  in 
the  Dublin  Hospital  Reports.  His  description 
of  the  anatomical  characters  of  the  disease  cor- 
responds so  exactly  with  what  I  have  many 
times  witnessed,  that  I  cannot  refrain  from 
quoting  it.  "  When  the  dilated  (left)  auricle 
is  cut  into  and  cleared  of  the  blood  it  contains, 
at  its  lowest  part,  instead  of  the  mitral  valve,  a 
concave  membranous  septum  of  a  yellow  colour 
is  seen,  which  is  perforated  by  an  oblong 
fissure,  about  half  an  inch  in  length,  and  one  or 
two  lines  broad ;  this  fissure  I  have  observed 
to  be  always  obliquely  situated,  and  to  run 
parallel  to  the  septum  of  the  ventricles ;  it  ge- 
nerally is  of  a  semilunar  form,  the  concavity  of 
the  curve  looking  towards  the  root  of  the  aorta, 
the  convexity  backwards  ;  the  first  formed  by 
the  larger  portion  of  the  mitral  valve,  the  latter 
by  the  smaller ;  the  edges  of  this  oblong  fissure 


are  generally  studded  with  long  depositions ; 
viewed  from  the  left  ventricle,  the  membranous 
septum  is  convex,  and  the  angles  of  the  fissure 
are  connected  by  shortened  chords  tendineas, 
with  two  very  thick  fleshy  columns,  the  one  in 
front,  the  other  behind." 

Dilatation  of  the  valves. — We  sometimes 
find  the  valves  of  the  heart  in  a  dilated  or  aneu- 
rismal  state.  Laennec  has  placed  on  record  an 
example  of  this  affecting  the  mitral  valve  ;*  "  A 
little  pouch,  half  an  inch  long  and  more  than 
four  lines  in  diameter,  projected  on  the  supe- 
rior surface  of  this  valve,"  i.  e.  into  the  left 
auricle.  Mr.  Thurnam  has  appended  the 
detail  of  several  cases  to  his  memoir  already 
quoted  on  Aneurisms  of  the  Heart. f  He  de- 
scribes a  specimen,  preserved  in  the  Hunterian 
Museum,  affording  an  example  of  four  aneuris- 
maj  pouches  of  the  tricuspid  valve.  The  sime 
writer  likewise  records  a  case  in  which  there 
was  congenital  absence  of  one  aortic  valve;  the 
two,  which  were  present,  were  thick  and  fleshy, 
and  rough  on  their  ventricular  surfaces.  The 
edge  of  the  one  was  smooth,  that  of  the  other 
rugged  ;  there  was  a  deposit  of  ossific  matter  at 
their  points  of  attachment.  From  the  ventricu- 
lar surface  of  the  valve  with  the  smooth  border, 
there  projected  a  little  bag  that  would  hold  a 
swan-shot,  and  which  opened  by  a  little  round 
mouth  on  the  aortic  surface  of  the  valve.  It 
had  two  little  slits  in  its  most  depending  por- 
tion, and  was  evidently  formed  by  a  dilatation 
of  the  valve  itself." 

Atrophy  of  the  valves. — We  have  a  familiar 
instance  of  atrophy  of  valves  in  the  case  of  the 
Eustachian  valve,  which  undergoes  as  it  were  a 
sort  of  natural  atrophy  from  the  commencement 
of  extra-uterine  life.  The  valve  becomes  cri- 
briform, and  the  holes  by  which  it  is  pierced 
gradually  enlarge  and  coalesce,  and  in  this  way 
the  valve  is  worn  away.  We  often  find  one  or 
more  of  the  semilunar  valves  perforated  by 
openings  of  a  similar  kind,  without  the  co-ex- 
istence of  any  other  disease  ;  the  margin  of  the 
opening  is  always  smooth,  and  the  valve  itself 
thinner  and  more  flaccid  than  is  natural.  Ac- 
cording to  Dr.  Williams,  the  wasting  affects  the 
posterior  portion  of  the  mitral  valve,  "  the 
membrane  of  which  is  often  annihilated  by  it, 
the  cords  being  inserted  directly  into  the  auri- 
cular ring."  The  anterior  lamina  is  also  occa- 
sionally found  much  shortened,  and  without 
those  fine  thin  expansions  of  membrane  which 
commonly  unite  the  cords  to  each  other,  below 
their  insertion  into  the  thicker  part  of  the 
valve. 

.Entozoa  in  the  heart. — The  occurrence  of 
entozoa  in  the  human  heart  must  be  considered 
to  be  extremely  rare,  at  least  the  cases  on  record 
which  may  be  depended  on  are  very  few. 
Andral  states  that  he  found  the  cysticercus 
once  in  the  human  heart,  but  has  seen  it  fre- 
quently in  the  hearts  of  measly  pigs.  Many 
examples  are  mentioned  by  various  authors  of 
ascarides,  filaria?,  cercariae,  and  other  entozoa 
in  the  hearts  of  dogs  and  many  other  of  the  in- 

*  Quoted  in  Bouillaud's  work,  t.  ii.  p.  510. 
t  Log.  cit. 


648 


ANIMAL  HEAT. 


ferior  animals,  Mammalia,  as  well  as  birds, 
reptiles,  and  fishes.* 

States  of  the  blood  in  the  heart  after  death. — 
"What  appears  to  be  the  natural  state  of  the 
contents  of  the  heart  after  death  is  as  follows. 
The  right  auricle  contains  a  coagulum  of  dark 
fclood,  and  the  right  ventricle  contains  a  similar 
one,  of  less  size ;  a  very  small  quantity  of  coa- 
gulum or  of  fluid  blood  is  found  in  the  left 
cavities,  and  it  is  not  uncommon  to  find  a  coa- 
gulum extending  into  the  aorta  ;  white  coagula 
are  often  found  in  these  cavities.  Sometimes 
these  coagula,  especially  at  the  right  side, 
adhere  closely  to  the  wall  of  the  cavity  in  which 
ihey  are  situated,  and  appear  as  it  were 
moulded  upon  it,  sinking  into  the  interstices 
between  the  fleshy  columns,  so  as  to  render  it 
difficult  to  remove  them.  The  modification 
which  we  most  frequently  meet  with  in  this 
state  of  the  heart's  contents,  is  that  in  cases  of 
asphyxia;  affording,  however,  merely  an  in- 
stance of  aggravation,  if  I  may  so  speak,  of  the 
natural  state ;  the  right  cavities  and  the  vessels 
leading  to  and  from  them  are  gorged  with  dark 
blood,  liquid  or  coagulated,  while  the  left  cavi- 
ties are  nearly  empty.  Such  states  of  the 
heart's  cavities,  it  is  obvious,  are  formed  in 
articulo  mortis.  Fibrinous  masses,  either  mixed 
with  or  deprived  of  the  colouring  matter  of  the 
blood,  have  been  many  times  found,  which  it 
cannot  be  doubted  were  formed  in  the  heart  some 
time  prior  to  death,  and  probably  gave  rise  to 
symptoms  of  a  serious  nature;  these  are  the 
true  polypous  concretions  of  the  heart.  The 
manner  in  which  Mr.  Allan  Burns,  one  of  our 
earliest  British  writers  on  the  heart,  explains 
the  formation  of  some  of  these  concretions,  is 
deserving  of  attention.  "  If,"  he  says,  "  we 
strictly  scrutinize  all  the  reputed  cases  of  poly- 
pus in  the  heart,  we  shall  reduce  the  real  ex- 
amples of  this  affection  to  a  very  limited  num- 
ber indeed.  Still  we  shall  leave  a  few,  where 
there  is  reason  to  believe  that  the  concretion 
had  been  formed  a  very  considerable  time  be- 
fore death  :  but  it  must  be  understood,  that 
these  concretions  are  seldom  found  except  in 
hearts  otherwise  diseased.  In  health,  the  blood 
does  not  tarry  for  any  length  of  time  in  either 
the  heart  or  vessels;  it  is  incessantly  in  motion, 
circulating  with  greater  or  less  rapidity,  accord- 
ing to  the  state  of  the  heart  and  arteries.  The 
blood  never  in  health  remains  so  long  in  con- 
tact with  the  surfaces  of  the  heart,  as  to  allow 
of  its  being  changed  by  their  action.  In  some 
diseases  of  this  organ,  irregular  actions  are  ex- 
cited by  very  trifling  causes  ;  the  blood  stag- 
nates longer  in  the  heart  than  it  usually  does  or 
ought  to  do,  while  here  it  undergoes  changes 
by  the  reciprocal  action  of  the  blood  on  the 
heart  and  the  heart  on  the  blood ;  new  organized 
matter  is  deposited,  and  adheres  to  the  parietes 
of  the  cavity  in  which  it  is  lodged.  This  con- 
cretion slowly  increases,  the  first  panicle  acting 
as  the  exciting  cause  for  the  deposition  of  the 
second,  and  so  on." 

The  strongest  evidence  of  the  formation  of 

*  For  a  list  of  the  references  to  such  cases,  see 
South's  edit,  of  Otto,  Path.  Anat.  p.  293. 


such  coagula  some  time  before  death  consists 
in  their  being  organised  :  in  a  case  recorded  by 
the  writer  from  whom  the  preceding  passage 
was  quoted,  a  large  and  fully  organised  polypus 
was  found  in  the  right  auricle ;  its  attachment 
was  by  a  rough  surface  to  the  musculi  pectinati, 
and  its  body  hung  down  into  the  right  ventricle. 
It  very  much  resembled  a  nasal  polypus,  and 
it  was  so  firmly  fixed  to  the  heart,  that  it  allow- 
ed the  whole  mass  of  the  heart  and  a  consider- 
able portion  of  the  lungs  to  be  suspended  by  it, 
without  showing  any  tendency  to  separate.  It 
was  pendulous  and  tapered  from  below  up- 
ward ;  its  structure  was  dense  and  lamellated, 
and  not  a  single  red  globule  entered  into  its 
composition."  In  this  casp,  as  in  other  similar 
ones  quoted  by  Andral,  the  adhesion  of  the  po- 
lypus seemed  due  to  an  inflammation  of  the 
endocardium,  either  excited  by  the  contact,  or 
before  the  formation  of  the  coagulum.  That 
such  coagula  may  be  permeated  by  bloodves- 
sels is  proved  by  the  cases  of  Bouillaud  and 
Rigacci,  quoted  by  Andral :  in  the  latter  cases, 
these  reddish  filaments  passed  from  thecolumna: 
carrteae  and  entered  the  substance  of  the  poly- 
pous mass  :  they  had  all  the  appearance  of 
bloodvessels,  and  when  injected  with  mercury 
were  found  to  divide  into  a  number  of  small 
branches  that  ramified  through  the  substance  of 
the  polypus.  By  careful  dissection  it  was  as- 
certained that  the  tumour  was  formed  altogether 
of  a  mass  of  fibrine,  such  as  is  found  in  the  sac 
of  arterial  aneurisms  Pus  is  occasionally  found 
in  the  centre  of  these  fibrinous  concretions,  but 
whether  carried  to  the  heart  in  the  blood,  and 
accidentally  enclosed  in  the  coagulum  during 
its  solidification,  or  formed  in  the  coagulum  by 
some  action  within  it,  it  is  impossible  to  decide. 
Osseous  and  cartilaginous  deposits  toohave  been 
found  in  them,  as  in  the  case  from  Burns,  in 
which  one  of  these  polypi  was  ossified  in  several 
points,  and  so  perfectly  organized  that  on  inflat- 
ing the  coronary  vein,  a  number  of  minute  ves- 
sels on  the  surface  and  in  the  substance  of  the 
tumour  became  distended  with  air. 

(R.  B.  Todd.) 

HEAT,  ANIMAL.— Judging  merely  by 
our  sensations,  we  should  infallibly  conclude 
that  our  bodies  undergo  very  considerable 
changes  of  temperature.  This  belief  was  in- 
deed necessarily  entertained  previously  to  the 
time  when  natural  philosophy  had  discovered 
a  means  of  ascertaining  the  true  state  of  the 
matter.  The  application  of  the  thermometer 
has  dissipated  the  error.  But  then  error  of  an 
opposite  kind  was  run  into,  and  the  results  of 
a  very  limited  number  of  observations  led  men 
to  conclude  that  the  temperature  of  the  human 
body  was  invariable  or  nearly  so.  Still  the 
measures  of  temperature  given  by  different  ob- 
servers did  not  perfectly  accord,  though  each 
presented  his  conclusions  as  the  temperature 
of  the  race.  It  was  but  reasonable  to  imagine 
that  these  discrepancies  arose  not  from  any  want 
of  accuracy  in  observation,  but  from  diversities 
inherent  in  the  subjects  observed.  This  is 
now  known  to  be  the  case.  But  though  proofs 
of  this  truth  have  been  greatly  multiplied,  the 


ANIMAL  HEAT. 


649 


whole  subject  has  never  been  presented  in  a 
connected  and  systematic  manner. 

Since  it  is  proved  that  the  temperature  of 
the  human  body  varies,  we  can  only  obtain  an 
approximation  to  its  actual  amount  by  taking 
the  mean  of  all  the  good  observations  that 
have  ever  been  made,  being  particularly  care- 
ful to  include  the  extremes  ;  for  a  mean  gives 
but  a  very  imperfect  idea  of  a  term  that  ought 
to  represent  a  variable  number,  if  the  limits 
are  not  at  the  same  time  assigned  and  taken 
into  the  account.  The  best  observations  of  this 
kind,  provided  they  be  sufficiently  numerous, 
will  be  those  that  have  been  made  by  the  same 
individual,  inasmuch  as  there  is  great  likeli- 
hood that  he  will  always  have  made  use  of  the 
same  procedure  and  of  the  same  instruments, 
by  which  the  results  become  more  readily  com- 
parable one  with  another. 

Temperature  of  the  human  eody. — 
In  the  following  obseivations  we  shall  make 
use  of  the  measures  of  temperature  given  by 
Dr.  John  Davy.  These  amount  to  one  hun- 
dred and  fourteen  in  number,  and  were  made 
on  individuals  of  both  sexes  and  of  different 
ages  in  three  quarters  of  the  world,  in  Europe, 
Asia,  and  Africa,  in  different  latitudes,  under 
various  temperatures,  and  among  individuals 
of  different  races.  But,  as  the  knowledge  of 
the  mean  and  extreme  temperatures  of  the 
body  of  man  would  have  little  value  apart 
from  the  statement  of  the  circumstances  and 
conditions  under  which  they  were  ascertained, 
we  shall  at  the  same  time  give  the  ages  of  the 
subjects  and  the  temperature  of  the  air  at  the 
time  of  the  observations. 

The  mean  age  of  the  subjects  of  Dr.  Davy's 
observations  was  twenty-seven  years.  The  mean 
temperature  oftheairwas  23°,  3  c.  (74°  F.*) be- 
tween the  limits  of  1.5°,  5  (60°  F.)  and  27°,  8 
(82°  F.).  In  these  circumstances  the  mean 
temperature  of  the  body,  which  was  always 
taken  in  the  mouth,  was  37°,  7  (100°  F.)  be- 
tween the  extremes  35°,  8  (96°,  5  F.)  and 
38°,  9  (102°  F.).  The  greatest  difference  in 
one  hundred  and  fourteen  observations,  there- 
fore, scarcely  exceeded  three  degrees.  The 
temperature  of  the  human  body  thus  obtained 
might  be  considered  as  exact  if  the  conditions 
of  age  and  external  atmospheric  temperature 
approached  pretty  closely  to  their  respective 
means.  This,  in  fact,  was  the  case  as  regards 
the  first  term,  but  not  as  concerns  the  second  ; 
for  some  of  the  observations  were  made  under 
very  intense  degrees  of  heat,  such  as  27°,  8  (82° 
F.),  but  none  at  the  opposite  extreme,  or  at  a 
temperature  which  could  be  reputed  cold,  a 
temperature  of  15°  (59°  F.)  being  already  suf- 
ficiently agreeable.  So  that  if  the  temperature 
of  the  air  influences  that  of  the  body,  a  ques- 
tion which  we  shall  examine  by-and-by,  the 
mean  which  we  have  stated  as  the  temperature 
of  the  species  would  be  too  high. 

It    is   of    some   consequence    to  pursue 

*  [The  valuations  according  to  Fahrenheit's  scale 
the  editor  desires  may  be  regarded  as  mere  though 
close  approximations  to  the  indications  according  to 
the  centigrade  scale.] — Ed. 


these  inquiries  among  the  lower  members  of 
creation,  among  animals ;  and  the  writer  to 
whom  we  are  indebted  for  the  observations 
quoted  upon  man  has  also  made  a  great  num- 
ber upon  the  lower  animals.  We  shall  there- 
fore continue  to  make  use  of  this  series  of 
experiments,  as  we  have  already  made  use  of 
that  which  bore  upon  man  individually. 

Temperature  of  the  Mammalia. — The 
observations  here  were  made  on  thirty-one  dif- 
ferent species  taken  from  among  the  principal 
divisions  of  this  class,  and  under  a  mean  tem- 
perature of  the  external  air  equal  to  25°  (77° 
F.),  between  the  limits  of  15°  (59°  F.)  and  30° 
(86°  F.). 

The  mean  temperature  of  the  body  of  the 
Mammalia  was  38°,  4  (101°,  10  F.),  the  max- 
imum being  40°,  5  (105°  F.),  the  minimum 
37°,  2  (99°  F.).  The  extent  of  variation  Con- 
sequently presented  by  the  Mammalia,  3°,  3 
of  the  centigrade  scale  (6°  F.),  is  nearly  equal 
to  that  exhibited  by  man.  But  there  is  this 
difference  between  the  two  scales,  that  the 
extremes  and  the  mean  in  the  case  of  man  are 
inferior  to  the  corresponding  terms  in  the  case 
of  the  Mammalia. 

Temperature  of  Birds. —  The  observa- 
tions here  were  made  on  fifteen  species  in 
different  orders.  The  mean  temperature  of  the 
air  was  26°,  1  (79°  F.),  between  the  extremes 
15°  (59°  F.)  and  31°,  5  (88°,  75  F.).  The 
temperature  of  the  subjects  of  the  experiments 
offered  a  mean  of  42°,  1  (107°,  86  F.),  the  su- 
perior limit  being  43°,  9  (111°  F.),  the  inferior 
37°,  2  (99°  F.).  The  temperature  of  birds, 
therefore,  presents  a  scale  much  more  exten- 
sive than  that  of  man  and  the  Mammalia, 
amounting  to  as  many  as  6°,  7  degrees  centi- 
grade (12°  F.).  It  also  stands  above  both  of 
the  others  in  the  point  of  its  mean,  which  is 
higher  by  3°,  7  (6°  F.  nearly)  in  its  upper 
limit,  and  5°  centigrade  (about  9°  F.)  higher 
in  its  lower  limit.  The  lower  limit,  in  tact, 
corresponds  very  nearly  with  the  mean  term  of 
the  heat  of  the  Mammalia  as  exhibited  in  the 
preceding  scale.  But  in  neither  scale  can  we 
say  much  in  regard  to  the  inferior  limit,  inas- 
much as  no  observation  was  taken  at  a  tem- 
perature lower  than  that  of  fifteen  degrees  cen- 
tigrade (59°  F.). 

When  we  compare  the  preceding  statements 
of  the  temperature  of  animals,  it  is  apparent 
that  it  varies  but  little  between  one  species  and 
another  of  the  same  class.  In  passing  to  dif- 
ferent classes,  however,  the  difference  becomes 
very  considerable,  and  though  the  observations 
are  here  much  fewer  in  number,  they  are  per- 
fectly satisfactory  as  regards  the  general  result. 

Temperature  of  Reptiles. —  From  nine 
observations  made  on  members  of  the  four 
orders  of  Reptiles,  Dr.  Davy  found,  the  ex- 
ternal air  having  a  mean  temperature  of  26°,  5 
(79°,  75  F.)  between  the  extremes  32°  and  16° 
(89°,  5  and  60°,  75  F.),  that  the  temperature 
of  Reptiles  was  not  higher  than  28°  (82°,  5  F.). 

Temperature  of  Fishes. — If  from  Rep- 
tiles we  pass  to  Fishes,  corresponding  and 
even  more  remarkable  differences  are  perceived. 
Dr.  Davy,  indeed,  gives  the  temperature  of 


650 


ANIMAL  HEAT. 


no  more  than  five  species,  but  they  belonged 
to  very  different  orders.  The  mean  external 
temperature  being  22°,  3  (72°,  F.),  that  of 
fishes  was  found  to  be  but  23°,  2  (74°  F.), 
which  is  very  little  more  than  one  degree  cen- 
tigrade higher.  This  difference  becomes  even 
more  striking,  if  possible,  as  we  descend  in 
the  scale  of  animals. 

Temperature  of  Insects. —  From  eight 
observations  on  Insects  of  very  dissimilar  spe- 
cies, the  mean  temperature  of  the  air  being 
24°  (75°,  5  F.),  that  of  the  insects  was  24°,  2 
(75°,  75  F.) 

Temperature  of  the  Crustacea. — Two 
species  of  Crustaceans,  the  cray-fish  and  crab, 
presented  a  still  more  interesting  phenomenon. 
The  mean  temperature  of  the  air  was  24°,  4 
(76°  F.)  at  the  time  of  experimenting,  that  of  the 
Crustacea  24°,  1,  or  somewhat  lower  than  the 
ambient  medium.  This  we  do  not  presume  to 
present  as  the  rule,  but  we  would  say  that  the 
temperature  of  the  Crustacea  is  nearly  equal 
to  that  of  the  medium  in  which  they  are 
plunged. 

Temperature  of  the  Mollusca. —  In 
observing  the  temperature  of  a  single  Mollusc, 
the  common  oyster,  the  temperature  of  the  sea 
being  27°,  8,  (82°  F.)  that  of  the  animal  was 
27°,  8  also. 

It  is  obvious,  therefore,  that  the  differences 
in  the  temperature  of  animals  from  reptiles 
inclusively  downwards  is  very  inconsiderable. 
All  these  animals,  indeed,  may  he  united 
under  a  single  category,  and  regarded  as  con- 
stituting a  single  group  characterised  by  the 
state  or  degree  of  their  temperature.  The 
same  may  also  be  done  with  reference  to  the 
animals  of  the  two  higher  classes,  Mammalia 
and  Birds,  which  in  point  of  temperature  are 
so  nearly  akin  to  each  other. 

There  are  consequently  two  grand  divisions 
of  animals  as  regards  temperature ;  the  one 
comprising  the  Mammalia  and  Birds ;  the 
other  including  Reptiles,  Fishes,  Insects,  Crus- 
taceans, and  Molluscs.  The  first  is  known 
under  the  name  of  warm-blooded  animals,  the 
second  under  that  of  cold-blooded  animals. 

To  characterize  the  first  under  the  view  of 
temperature,  the  mean  of  the  temperatures  of 
the  respective  classes  which  compose  it  must 
first  be  taken.  From  the  experiments  of  Dr. 
Davy  the  mean  temperature  of  Mammalia  ap- 
pears to  be   38°,   4  (101°   F.  ) 

that  of  birds    42°,    1  (108°   F.  ) 

Mean  of  both  classes  40°,  25  (104°,  5  F.) 


We  may  therefore  say  that  the  mean  tempe- 
rature of  warm-blooded  animals,  including 
man,  surrounded  by  a  moderate  external  tem- 
perature is  in  round  numbers  40°  (104  F.) 
between  the  limits  of  36°  and  44°  (97°  and 
111°,  5  F.),  by  which  we  have  a  scale  of  dif- 
ference amounting  to  8°  (about  14°  F.). 

The  other  class,  that,  namely,  including  the 
cold-blooded  animals,  having  no  peculiar  tem- 
perature proper  to  them,  may  be  characterized 
in  the  following  manner: — their  temperature 
differs  little  or  not  at  all  from  that  of  the  sur- 


rounding media  in  which  they  live,  when  this  is 
at  a  degree  which  may  be  called  moderate;  so 
that  the  differences  are  either  inappreciable,  or 
do  not  exceed  the  limits  of  +  4  (39°,  50  F.). 
We  shall  return  by-and-by  upon  this  character, 
which  requires  development. 

General  conditions  of  organization  in  relation 
with  the  production  of  a  greater  or  less 
degree  of  heat. 

So  wide  a  difference  in  the  heat  of  the  two 
categories  of  animals  might  lead  to  the  pre- 
sumption that  there  is  also  a  very  great  dif- 
ference in  point  of  structure.  If,  indeed,  this 
relation  exists  and  is  easily  detected,  we  may 
be  led  to  discover  the  general  conditions  of 
organization  upon  which  the  production  of 
heat  depends.  Is  there  an  organization  com- 
mon to  Mammalia  and  Birds,  distinct  and 
different  from  that  belonging  to  the  other 
classes  of  animals  ?  This  question  can  be  an- 
swered in  the  affirmative  :  there  is  a  well-marked 
diversity  of  organization  which  distinguishes 
Mammalia  and  Birds  from  all  other  animals. 

I.  The  most  prominent  feature  of  diversity 
exists  in  the  sanguiferous  system,  which  is 
divided  through  its  entire  extent  into  two  dis- 
tinct parts  without  direct  communication  be- 
tween them,  the  heart  presenting  a  complete 
median  septum,  the  bloodvessels  in  like  man- 
ner forming  two  systems  of  canals,  which 
have  also  no  immediate  communication  in  their 
trunks. 

II.  This  peculiarity  of  structure,  which  is 
only  met  with  among  animals  having  warm 
blood,  is  regularly  associated  with  an  organ 
adapted  for  aerial  respiration.  The  character 
which  distinguishes  this  respiratory  organ  from 
the  one  met  with  among  cold-blooded  animals, 
reptiles  especially,  is  this,- — that  either  in  itself 
or  its  appendices  (the  air-sacs  of  birds)  it  pre- 
sents a  much  larger  extent  of  surface  in  relation 
with  the  air. 

III.  Warm-blooded  animals  are  farther  dis- 
tinguished from  the  cold-blooded  by  important 
modifications  of  the  digestive  canal.  1.  The 
first  portion  of  the  apparatus  from  the  mouth 
to  the  stomach  is  much  more  complex  in  them; 
for  instance,  it  presents  either  a  much  more 
perfectly  developed  dental  system,  fitted  to 
divide  the  food,  or  a  sac,  as  among  birds, 
fitted  to  macerate  the  aliment,  and  cause  it  to 
undergo  a  kind  of  preparatory  digestion  before 
it  is  passed  to  the  stomach.  2.  The  stomach 
is  more  distinct;  either  the  entrance  to  and 
exit  from  this  pouch  are  better  marked,  being 
often  provided  with  a  valve,  as  in  the  Mam- 
malia, or  its  structure  and  form  are  more  spe- 
cial, as  we  observe  it  among  Birds.  3.  The 
intestinal  canal  is  much  longer  in  the  warm 
than  in  the  cold-blooded  tribes. 

IV.  The  nervous  system  presents  diversities 
still  more  important  and  well-marked.  The 
most  striking  character  exists  in  the  proportion 
of  the  principal  trunk  of  this  system,  and 
especially  of  its  encephalic  extremity,  which 
is  much  larger  in  the  warm  than  in  the  cold- 
blooded animals. 

The  most  remarkable  structural  conditions 


ANIMAL  HEAT. 


651 


of  warm-blooded  animals,  then,  are  four  in 
number,  three  of  which  are  referable  to  the 
organs  of  nutrition,  the  fourth  to  the  nervous 
system,  which  may  be  briefly  related  in  the' 
following  order: — 1.  higher  complication  and 
greater  extent  of  the  digestive  apparatus;  2. 
entire  separation  of  the  circulating  apparatus 
into  two  systems,  the  venous  and  arterial,  with- 
out direct  communication  between  them;  3. 
organs  of  aerial  respiration  presenting  a  much 
larger  surface  to  the  contact  of  the  atmosphe- 
rical air;  4.  a  nervous  system  of  which  the 
axis,  and  especially  the  encephalic  extremity, 
bears  a  very  high  ratio  to  the  whole. 

These  structural  characters  determine  the 
following  modifications  of  function.  1st, 
The  complexness  and  greater  extent  of  the  di- 
gestive apparatus  in  warm-blooded  animals 
produces  a  more  perfect  elaboration  of  the 
matters  which  serve  for  the  formation  of  blood. 
2nd,  The  arrangement  of  the  parts  of  the  cir- 
culating system  maintains  the  arterial  blood 
quite  distinct  from  the  venous,  and  in  a  state 
of  complete  purity.  3rd,  The  respiratory  ap- 
paratus, by  the  great  extent  of  its  surfaces  in 
contact  with  the  air,  secures  that  its  distinguish- 
ing qualities  be  imparted  in  the  highest  pos- 
sible degree  to  the  arterial  blood,  which  more- 
over is  elaborated  in  larger  quantity.  The 
predominance  of  their  nervous  system,  and  es- 
pecially of  its  encephalic  extremity,  renders 
all  the  parts  of  the  body  much  more  excitable, 
and  gives  the  greatest  energy  to  the  nutritive 
functions.  The  whole  of  these  organic  condi- 
tions are  mutually  dependent,  and  may  be 
reduced  to  the  expression  of  these  two  general 
conditions: — -1st,  the  formation  and  distri- 
bution of  the  arterial  blood,  the  particularly 
exciting  and  nutritive  blood  of  the  body  ;  2nd, 
the  most  powerful  influence  of  the  nervous 
system. 

As  these  characters  of  primary  significance 
in  the  animal  economy  coincide  in  Mammalia 
and  Birds  with  the  greater  production  of  heat, 
and  thus  distinguish  them  from  all  other  ani- 
mals, it  is  probable  that  between  these  organic 
conditions  and  caloricity  or  the  power  of 
evolving  caloric,  there  is  a  relation  of  the  na- 
ture of  cause  and  effect.  It  is  even  almost 
impossible  that  this  should  be  otherwise  than 
as  it  has  been  stated  ;  for  the  characters  of 
organization  and  the  peculiarities  of  function, 
coincident  with  the  greater  evolution  of  caloric, 
are  almost  the  sole  points  of  any  importance 
that  distinguish  warm  from  cold-blooded  ani- 
mals. 

It  is  therefore  nearly  certain  that  the  condi- 
tions requisite  to  the  production  of  heat  must 
exist  within  the  circle  of  the  functions  which 
we  have  described.  And  if  this  relation  do 
actually  exist — as  these  functions  are  in  a 
state  of  mutual  dependence, — it  follows  that 
one  of  them  cannot  be  modified,  the  others 
remaining,  so  to  speak,  in  the  same  condition, 
without  modification  resulting  in  the  calorific 
capacity  likewise.  It  is  of  great  consequence 
to  verify  this  assumption,  because  if  it  be 
well-founded,  the  probability  already  elicited 
of  the  power  of  engendering  heat  being  de- 


pendent on  the  state  of  the  functions  in  the 
relations  which  have  been  indicated,  becomes 
matter  of  certainty.  So  that  it  is  of  the  highest 
import  to  follow  the  modifications  of  these 
functions  presented  by  animals  and  man  in 
order  to  compare  them  with  the  respective 
varieties  of  calorific  power  presented  by  each. 
And  if  we  find  that  they  coincide,  and  accord 
with  the  principle  established,  we  shall  have 
discovered  the  conditions  of  organization  and 
of  function  upon  which  the  production  of  ca- 
loric depends. 

Conditions  of  organization  and    of  func- 
tions may  be  entitled  the  physiological  causes 
of  the  production  of  animal  heat.    If  we 
succeed  in  determining  these,  we  ought  to 
rest  satisfied.    If,  indeed,  to  this  knowledge 
we  could  add  that  of  the  immediate  cause  of 
this  phenomenon  among  animals,  or  what  is 
the  physical  cause,  it  would  be  a  great  gain 
for  science.    This,  accordingly,  was  the  ob- 
ject of  the  labours  of  the  majority  of  phy- 
siologists who  have  given  their  attention  to  the 
subject  of  animal  heat.  But  they  could  not  possi- 
bly succeed  in  their  researches,  for  the  simple 
reason  that  natural  philosophers  themselves  have 
not  yet  discovered  how  heat  is  produced  in  the 
inorganic  world ;  although  indeed  they  have 
presumed  that  they  were  acquainted  with  it. 
It  is  not  to  be  wondered  at,  then,  that  attempts 
have  been  made  to  detect  this  presumed  cause 
amidst  the  complicated  phenomena  of  life. 
But  natural  philosophers  have  lost  confidence 
in  the  theory  which  they  had  formed,  and  are 
searching  for  a  new  one.    Meantime  they  are 
doing  what  ought  always  to  be  done  under 
such  circumstances  ;    they  are  studying  with 
care  the  various  conditions  and  circumstances 
in  which  it  is  produced  ;   determining  these 
with  precision,  and  measuring  with  rigour  the 
quantity  of  heat  produced.    Of  late,  therefore, 
many  distinguished  physiologists  have  entered 
on  the  same  path,  and  by  experiment  have 
endeavoured  to  ascertain  the  physiological  con- 
ditions of  the  production  of  heat.     But  if 
their  predecessors  have  not  attained  the  object 
they  had  in  view,  they  have  nevertheless  ren- 
dered very  essential  services  to  science  ;  for  in 
searching  after  the  physical  cause  of  heat,  they 
have  determined  with  precision  the  physiological 
conditions  of  the  production  of  animal  heat, 
which  are  of  very  great  importance.  Inde- 
pendently of  the  simple  observation  of  the  actual 
temperature  of  animals,  the  labours  of  physio- 
logists on  this  subject  consist  almost  entirely 
of  experimental  facts,  that  is  to   say,  facts 
created  by  science. 

But  there  is  one  source  of  inquiry  into  the 
laws  of  animal  heat  which  has  been  little 
dipped  into,  although  it  is  beyond  all  comparison 
the  most  abundant.  I  allude  to  that  presented 
to  us  by  nature  in  the  all  but  infinite  variety 
of  modifications  of  organization  and  pheno- 
mena exhibited  in  the  vast  chain  of  animated 
things,  not  only  in  the  diversities  of  species, 
but  also  in  the  varieties  of  age  and  constitution, 
and  the  changes  induced  by  the  states  of  health 
and  disease.  In  making  this  an  object  of 
peculiar  study,  we  become  acquainted  with 


652 


ANIMAL  HEAT. 


the  greatest  possible  number  of  phenomena 
connected  with  animal  heat ;  and  in  determin- 
ing the  physiological  conditions  of  its  produc- 
tion, we  shall  lay  up  a  store  of  theoretical 
knowledge  peculiarly  applicable  to  practice, 
the  end  and  object  of  all  physiological  inves- 
tigation. 

The  means  of  comparing  these  modifications, 
however,  and  of  judging  of  their  importance 
are  not  always  easy.  We  shall  do  as  much  as 
the  actual  state  of  our  knowledge  permits  if 
we  inquire  first,  by  what  means  we  can  ap- 
preciate the  modifications  relative  to  the  arterial 
blood. 

1.  As  regards  the  quantity  of  the  arterial 
blood,  we  shall  view  this  point  of  the  inquiry 
less  with  reference  to  the  whole  amount  of 
blood  circulating  in  the  body,  than  to  the 
quantity  which  is  formed  at  a  time,  as  it  were, 
in  the  lungs;  because  it  is  evident  that  if  the 
arterial  blood  influences  the  phenomenon  of 
heat,  the  more  that  is  formed  at  any  given 
time  the  greater  ought  to  be  the  direct  or  in- 
direct influence  upon  the  production  of  heat. 
a.  As  it  is  not  always  possible  to  have  a  direct 
and  precise  measure  of  the  relative  quantity  of 
blood  in  the  organs,  we  must  be  content  with 
an  approximative  mode  of  estimating  this, 
which  consists  in  ascertaining  in  what  degree 
the  lungs  are  loaded  with  blood,  b.  Anaid  to  the 
judgment  may  also  be  derived  from  the  relative 
size  of  the  lungs,  the  tissue  being  presumed  to 
be  nearly  alike  throughout  their  entire  mass, 
c.  With  an  equal  volume  of  lungs,  the  greater 
or  less  compactness  of  the  tissue  must  be  taken 
into  the  account.  The  closer  the  tissue  is, 
the  more  are  the  surfaces  in  contact  with  the 
air  multiplied,  d.  The  extent  and  rapidity  of 
the  respiratory  motions  form  another  element 
in  the  calculation;  for  to  increase  the  amount 
of  relation  with  the  air  is  analogous  to  the  for- 
mation of  a  larger  quantity  of  arterial  blood 
within  a  given  time. 

All  the  foregoing  data  refer  to  the  absolute 
or  relative  quantity  of  arterial  blood.  But 
there  are  other  particulars  connected  with  its 
constitution  which  it  is  necessary  to  mention. 
The  blood,  for  instance,  is  composed  of  a  fluid 
and  solid  part,  the  latter  existing  under  the 
form  of  globules.  It  is  obvious  that  the  fluid 
is  not  the  characteristic  part  of  the  blood,  in- 
asmuch as  this  is  met  with  elsewhere,  whilst 
the  globules  of  the  blood  are  only  known  as 
constituents  of  this  fluid.  The  arterial  blood 
consequently  ought  to  have  qualities  by  so  much 
the  more  distinctive  and  energetic  as  it  con- 
tains a  larger  proportion  of  globules.  Now 
this  is  a  character  that  may  be  appreciated  with 
exactness,  and  measures  of  it  have  been  given. 
But  the  globules  of  the  blood  are  not  in- 
variably of  the  same  nature,  a  fact  which  may 
be  judged  of  by  outward  and  very  obvious  and 
appreciable  characters,  namely,  size  and  form. 
The  smallness  and  more  or  less  perfectly  sphe- 
rical or  rounded  form  of  the  blood-globules 
distinguishing  animals  with  warm  blood,  co- 
incide in  the  Vertebrata  with  a  higher  capacity 
to  produce  heat.  For  we  do  not  institute  this 
comparison  here  save  in  reference  to  animals 


included  in  this  division,  inasmuch  as  the  cha- 
racters of  the  blood  have  only  been  studied 
under  these  relations  among  them.  We  shall, 
therefore,  hold  the  energy  of  the  calorific  power 
to  be  connected  with  the  smallness  and  rounded 
form  ot  the  globules  of  the  blood  in  vertebrate 
animals. 

2.  The  materials  of  the  blood  being  sup- 
plied by  the  digestive  apparatus,  we  might 
judge,  all  things  else  being  equal,  of  the  per- 
fection of  the  blood  by  the  perfection  of  this 
apparatus.  But  there  is  likewise  a  necessary 
co-relation  between  the  result  of  the  function, 
and  the  aliment;  for  instance,  when  the  ap- 
paratus shall  be  found  nearly  alike  in  any  two 
cases,  the  difference  of  food  necessarily  in- 
fluencing the  qualities  of  the  blood,  the  com- 
parison must  be  established,  every  other  cir- 
cumstance beins;  equal,  according  to  the  higher 
or  lower  nutritive  qualities  of  the  food. 

As  the  use  of  the  arterial  blood  is  to  excite 
and  nourish  the  different  parts  of  the  body, 
there  will  be  a  necessary  correspondence  be- 
tween the  blood  and  the  result  of  the  nutrition 
which  may  become  manifest  in  the  nature  and 
quality  of  the  tissues.  And  in  this  case  it 
would  be  fair  to  make  use  of  these  characters 
of  tissues  to  form  an  estimate  of  the  nature  of 
the  blood  in  reference  to  its  aptitude  to  pro- 
duce heat ;  and  this  we  shall  accordingly  do. 
But  even  in  the  event  of  all  these  characters 
failing  us,  there  is  another  source  whence  we 
can  derive  comparative  measurements,  which 
are  susceptible  of  very  rigorous  application. 

Since  it  is  necessary  that  the  venous  blood 
should  pass  through  the  lungs  in  order  to  be- 
come arterial  from  contact  with  the  air  of  the 
atmosphere,  it  is  obvious  that  it  cannot  un- 
dergo any  change  in  its  constitution  without 
the  air  at  the  same  time  suffering  a  change. 
That  the  air  is  altered  by  the  respiratory  act  is 
well  known  to  all,  and  as  there  is  a  necessary 
co-relation  between  the  blood  aerated  during 
respiration  and  the  air  which  it  alters,  the 
amount  of  alteration  undergone  by  the  one 
may  be  estimated  from  the  change  suffered  by 
the  other.  The  quantity  of  air  altered  by  re- 
spiration, all  other  things  being  equal,  ought 
to  be  found  in  relation  with  the  production  of 
heat. 

The  different  characters  which  we  have  men- 
tioned all  refer  directly  or  indirectly  to  the 
blood.  There  still  remains  one  of  another 
order  which  may  also  serve  us  as  a  guide  in 
making  comparisons  in  reference  to  the  pro- 
duction of  heat.  The  allusion  here  made  is 
to  the  nervous  system,  the  superior  value  of 
which  in  warm-blooded  animals  has  already 
been  commented  on.  It  is  thus,  then,  that  we 
may  assume  the  predominance  of  the  nervous 
axis,  and  particularly  of  its  encephalic  ex- 
tremity, as  a  condition  favourable  to  the  pro- 
duction of  heat,  and  which,  in  circumstances 
of  parity  among  the  other  conditions,  must 
tend  to  the  production  of  a  greater  quantity  of 
heat.  Such  are  the  modes  of  proceeding  which 
we  shall  follow  in  investigating  the  modi- 
fications of  the  organic  conditions  and  of  the 
functions  which  coincide  with  the  greater  evo- 


ANIMAL  HEAT. 


65 


lution  of  heat.  To  ascertain  whether  this 
coincidence  is  to  be  viewed  as  being  in  the 
mutual  relation  of  cause  and  effect,  it  imports 
to  know  whether  or  not  their  variations  are  in 
relation  with  those  of  the  heat  produced.  If 
they  coincide  whenever  we  compare  them,  pro- 
vided these  comparisons  are  but  sufficiently 
numerous,  we  shall  be  safe  in  admitting  a 
necessary  connexion  between  them.  We  were 
led  to  the  relation  which  engages  our  attention 
in  the  course  of  our  comparisons  of  warm- 
blooded animals  with  those  having  cold  blood 
considered  in  general.  Let  us  now  enter  upon 
a  comparison  of  the  same  kind,  but  more  par- 
ticular, whilst  we  take  account  of  the  most 
important  subdivisions  of  these  two  great 
groups  in  order  to  verify  our  first  inductions. 

We  shall  first  compare  Mammalia  and  Birds 
to  determine  which  of  the  two  classes,  in  con- 
formity with  the  principle  to  which  we  have 
been  led,  has  its  organization  most  favourable 
to  the  production  of  heat. 

The  lungs  of  Birds,  although  smaller,  are 
more  loaded  with  blood  than  those  of  the 
Mammalia,  and  are  in  communication  with  ex- 
tensive air-cells,  spreading  all  through  the  body 
and  even  penetrating  into  the  cavities  of  the 
bones,  so  that  the  air  may  be  said  to  penetrate 
the  body  generally,  and  to  be  in  contact  with 
the  ramifications  of  the  aorta  as  well  as  with 
those  of  the  pulmonary  artery  ;  the  blood  of  these 
animals  is  therefore  in  the  most  extensive  rela- 
tion imaginable  with  the  air  of  the  atmosphere. 
Again,  if  the  nature  of  the  blood  of  Birds  be 
considered,  independently  of  this  extensive 
relation  with  the  air,  the  organic  condition  here 
will  not  appear  less  favourable  to  them.  The 
globules  of  this  fluid,  indeed,  are  a  little  larger 
and  less  spherical  than  in  Mammalia,  which  is 
a  disadvantage ;  but  the  proportion  they  bear 
to  the  fluid  part  is  so  favourable  to  Birds  that 
this  circumstance  must  give  them  immensely  the 
advantage  in  reference  to  the  character  which 
engages  us.  With  regard  to  the  nervous  sys- 
tem, if  the  encephalic  extremity  is  developed 
in  a  minor  degree  in  Birds,  their  circulating 
and  respiratory  systems  act  with  greater  quick- 
ness. Lastly,  and  as  an  effect  of  the  whole  of 
these  conditions,  the  consumption  of  air  is  much 
greater  among  Birds  than  among  Mammalia. 

From  all  that  precedes,  it  follows,  if  the 
principles  already  laid  down  be  correct,  that 
Birds  ought  to  produce  the  greatest  quantity  of 
heat;  and  this  is  actually  the  case,  as  we  have 
seen  when  we  were  speaking  of  the  actual  tem- 
peratures of  the  different  classes  of  animals — 
the  mean  temperature  of  the  Mammalia  is 
38°,  4  (101°  F.),  that  of  Birds  42°  1  (108  F.). 
Here,  then,  is  a  powerful  confirmation  of  the 
relation  which  we  have  recognized  betwetn  the 
conditions  of  the  organization  and  the  produc- 
tion of  heat;  it  is  of  so  much  the  more  value 
as  the  relation  being  based  on  the  comparison 
of  two  classes  so  numerous,  the  verification  is 
made  on  a  scale  of  proportionate  extent.  We 
shall  extend  it  still  farther  by  contrasting  in  the 
same  manner  the  two  other  classes  of  the  Ver- 
tebrata,  Reptiles  and  Fishes. 

I.  The  organs  which  prepare  the  materials 


of  the  blood — the  digestive  apparatus  is  more 
complete  among  Reptiles  than  among  Fishes; 
1st,  in  the  dental  apparatus  when  it  exists; 
2d,  in  the  more  distinct  stomach;  3d,  in  the 
greater  length  of  the  intestines. 

II.  The  blood  of  Reptiles  is  superior  to  that 
of  Fishes  both  as  regards  the  nature  of  the 
globules  and  their  relative  proportion,  their  size 
being  smaller,  and  their  numbers  greater,  than 
among  Fishes. 

If  the  whole  of  the  blood  in  the  Reptile  is 
not  transmitted  through  the  organ  of  respira- 
tion, whilst  in  the  Fish  it  is,  a  larger  quantity 
of  this  fluid  is  brought  into  contact  with  the  air 
in  the  same  space  of  time  in  consequence  of 
the  greater  extent  of  surface  of  the  organ  in  the 
Reptile,  and  then  the  Reptile  has  the  farther 
immense  advantage  of  a  pulmonary  or  aerial 
respiration,  whilst  that  of  the  Fish  is  branchial 
or  aquatic.  To  conclude,  the  nervous  system 
of  Reptiles  is  much  more  developed  in  the 
cerebro-spinal  axis,  and  especially  in  the  ence- 
phalic extremity,  than  in  Fishes. 

From  this  comparison  it  follows  that  the 
organic  and  functional  conditions,  judging  of 
these  in  conformity  with  the  principles  which 
we  have  taken  as  our  guide,  are  much  more 
favourable  to  the  development  of  heat  in  Rep- 
tiles than  in  Fishes.  This  theoretical  deduction 
is  fully  confirmed  by  direct  observation,  as  we 
have  seen  above,  and  this  verification  becomes 
a  new  confirmation  of  the  accuracy  of  the  prin- 
ciple. 

We  continue  to  pursue  this  parallel  by  a 
summary  comparison  of  the  organization  in  its 
relations  with  the  production  of  heat  in  the 
cold-blooded  Veitebr-ata  and  the  Invertebrata 
generally.  A  glance  suffices  to  shew  the  vast 
inferiority  of  the  Invertebrata  in  this  as  in  every 
other  respect.  In  the  first  place  their  blood  is 
so  little  of  the  same  nature  as  that  which  has 
been  recognized  most  favourable  to  the  produc- 
tion of  heat,  that  it  wants  the  characters  whe- 
ther of  arterial  or  of  venous  blood.  The  blood 
of  the  Invertebrata,  with  the  exception  of  a 
very  small  group  (the  worms  with  red  blood), 
is  colourless.  In  the  structure  and  number  of 
its  globules  it  is  also  greatly  inferior.  The 
globules,  indeed,  may  be  smaller,  but  then  they 
are  of  a  much  more  simple  structure,  and  con- 
sequently lower  in  the  scale,  in  other  words 
more  imperfect.  In  the  relation  to  the  fluid 
part  of  the  blood  too,  they  are  in  much  smaller 
proportion  than  among  the  Vertebrata.  An 
analogous  character  is  manifest  in  the  tissues 
generally,  the  proportion  of  water  in  them 
being  incomparably  larger  in  the  Inverte- 
brate than  in  the  Vertebrate  series  of  animals. 
Finally,  there  is  an  immeasurable  inferiority  in 
the  nervous  systems  of  the  Invertebrate  com- 
pared with  even  the  lowest  of  the  Vertebrate 
series  of  animals. 

Ftom  all  this  it  results,  agreeably  to  the 
principle  of  which  we  are  now  showing  the 
application,  that  the  Invertebrate  ought  to  have 
a  much  smaller  capacity  of  producing  caloric 
than  even  the  cold-blooded  Vertebrate  animals; 
and  this  is  exactly  as  we  found  matters  to  be 
by  direct  experiment  in  regard  to  the  tempera- 


054 


ANIMAL  HEAT. 


tore  of  the  different  classes,  the  results  of  which 
have  been  already  stated.  The  comparison 
might  be  carried  out  in  regard  to  Insects  and 
the  Mollusca,  which  present  some  appreciable 
differences.  If  attention  were  confined  solely 
to  the  structure  of  the  greater  number  of  the 
organs  of  nutrition,  which  are  much  more 
largely  developed  in  Molluscs,  it  might  be 
inferred  that  they  had  a  higher  calorific  power 
than  Insects;  but  when  we  take  into  the  account, 
1st,  the  final  result  of  the  nutritive  functions, 
the  quality  of  the  tissues,  which  in  the  Mollusc 
are  much  more  loaded  with  watery  fluid,  by 
which  they  acquire  a  greater  degree  of  softness 
and  flaccidity,  (whence  the  class  has  its  name,) 
whilst  in  the  Insect  they  are,  on  the  contrary, 
as  remarkably  dry  and  firm ; — 2d,  when  the 
most  general  mode  of  respiration  is  compared 
in  the  two  divisions,  it  being  in  the  Insect 
aerial,  in  the  Mollusc  aquatic ;  3d  and  lastly, 
when  we  glance  on  the  one  hand  and  on  the 
other  at  the  state  of  the  nervous  system,  and 
observe  how  much  less  perfectly  this  is  developed 
in  most  of  the  Molluscs  than  in  the  Insect,  it  is 
impossible  not  to  perceive  that  according  to  the 
principles  influencing  the  production  of  heat, 
the  Mollusca  must  be  inferior  in  this  respect 
to  Insects.  This  is  indeed  the  result  of  obser- 
vations of  all  kinds,  however  imperfect  or 
limited  these  may  have  been,  as  we  have  seen 
above. 

It  is  impossible  to  carry  the  comparison 
further;  the  phenomena  connected  with  heat 
in  the  lower  grades  of  the  animal  creation 
become  inappreciable ;  and  this  even  in  virtue 
of  the  same  principle  that  has  been  an- 
nounced ;  for  the  tissues  are  found  to  become 
more  and  more  watery  as  we  descend  in  the 
scale,  till  at  length  the  solid  constituent  is 
almost  inappreciable.  Of  course  the  circulating 
fluid  must  be  watery  in  a  still  greater  ratio;  it 
contains  but  few  globules;  and  then  the  ner- 
vous system  falls  off  in  a  still  greater  propor- 
tion ;  it  becomes  more  and  more  imperfect,  till 
at  length  no  trace  of  it  is  to  be  discovered. 
We  thus  arrive  at  the  last  links  of  the  chain, 
after  having  run  over  the  whole  animal  king- 
dom, and  we  have  found  one  uniform  principle 
of  correspondence  between  organic  modification 
and  calorific  power.  It  were  difficult  to  imagine 
any  more  satisfactory  proof  of  a  principle  than 
has  been  afforded  ;  indeed  as  this  has  on  no 
one  occasion  been  found  belied,  we  are  fully 
authorized  to  regard  it  as  established. 

We  have  as  yet  examined  but  two  points  in 
reference  to  animal  heat;  1st,  the  temperature 
of  man  and  of  the  different  classes  of  animals; 
2d,  the  general  relations  of  organization  with 
the  production  of  heat.  In  mentioning  the 
temperature  in  any  case,  we  have  spoken 
of  it  as  determinate ;  and  farther,  to  have  data 
that  should  be  always  comparable,  the  tempe- 
ratures have  been  taken  regularly  in  the  same 
places, — viz.  the  mouth  m  man,  and  the  other 
extremity  of  the  intestinal  canal  in  animals. 
We  have  still  to  ascertain  whether  the  tempera- 
ture varies  or  is  identical  in  different  parts  of 
the  body. 

Temperature  of  different  parts  of  the  body. 


— There  is  no  need  of  the  thermometer  to  tell 
us  that  all  parts  of  the  body  do  not  at  all  times 
preserve  the  same  temperature.  We  are 
often  certain  that  the  extremities  are  colder 
than  the  trunk  for  example;  and  a  law  of 
decrease  of  temperature  in  the  ratio  of  the  dis- 
tance of  parts  from  the  heart  had  even  been 
deduced  from  this  observation.  But  when 
exact  measurements  came  to  betaken,  this  law 
was  soon  found  to  be  at  fault,  as  will  be  seen 
by-and-by  in  the  course  of  these  observations. 
Dr.  Davy,  in  taking  the  temperature  of  the 
different  parts  of  the  body  of  a  lamb,  found 
that  of  the  right  ventricle  of  the  heart  40°,  5 
(106°  F.),  that  of  the  left  ventricle  41°,  1  (106° 
F.).  The  left  ventricle  was  therefore  higher  in 
temperature  than  the  right  to  the  extent  of  a 
degree  of  the  scale  of  Fahrenheit's  thermometer. 
The  temperature  of  the  rectum  corresponded 
with  that  of  the  right  ventricle. 

In  my  inquiries  along  with  M.  Gentil 
into  the  relations  in  point  of  temperature  of 
certain  external  parts,  we  found  in  a  strong 
man,  perfectly  at  rest  in  mind  and  body, 
in  the  month  of  July,  the  external  air  being  at 
21°,  25  c.  (71°  F.),  the  temperature  of  the 
mouth  38°,  75  (102°  F.)  ;  that  of  the  rectum 
corresponded.  The  hands  presented  the  next 
highest  degree,  marking  nearly  37°,  5  (99°,  5  F.). 
What  is  remarkable  is  that  the  axillae  and 
groins,  which  corresponded  with  one  another, 
were  very  sensibly  lower  in  temperature  than 
the  hands ;  they  did  not  raise  the  thermometer 
higher  than  36°,  90  c.  (99°  F.).  The  cheeks 
marked  35°,  93  (90°,  5  F.),  the  temperature 
being  ascertained  by  enveloping  the  bulb 
of  the  thermometer  in  the  skin  of  these 
parts.  The  feet  were  a  little  lower,  35°  02 
(about  90°  F.) ;  their  temperature  being  deter- 
mined by  placing  the  thermometer  between  the 
two,  so  that  the  bulb  was  surrounded  on  every 
side.  The  temperature  of  the  feet  was,  there- 
fore, notably  lower  than  that  of  the  hands, 
differing  to  the  extent  of  1°,  88  of  the  centigrade 
scale  (above  3°  of  Fahrenheit's  thermometer). 
Placed  on  the  skin  between  the  thorax  and 
abdomen  the  thermometer  was  at  its  minimum, 
not  rising  higher  there  than  35°  (95°  F.);  but 
here  a  part  of  the  bulb  being  in  contact  with 
the  air,  there  must  have  been  considerable 
cooling. 

As  the  question  here  is  not  of  absolute  but 
merely  of  relative  temperatures,  we  can  make 
great  use  of  the  results  come  to  by  the  different 
writers  quoted.  We  shall  present  a  summary 
of  these  under  the  following  head. 

Relations  between  the  temperature  of  inter- 
nal parts. — 1st.  The  warmest  part  of  the  body, 
according  to  John  Hunter,  is  in  the  abdomen 
close  to  the  diaphragm.  2d.  The  next  part  in 
point  of  temperature  is  the  left  ventricle  of  the 
heart.  3d.  The  right  ventricle  of  the  heart  is 
the  next  in  succession.  The  rectum  and  the 
mouth  shut  are  of  the  same  temperature.  The 
greatest  difference  consequently  between  the 
temperature  of  these  internal  parts  does  not 
amount  to  more  than  1°  centigrade,  or  at  the 
utmost  2°  Fahrenheit. 

Supposing  the  relations  in  temperature  of  the 


ANIMAL  HEAT. 


655 


internal  parts  to  be  pretty  constant  in  the 
normal  state,  the  temperature  of  the  right  ven- 
tricle of  the  heart  and  of  the  rectum  may  be 
determined  by  taking  the  temperature  of  the 
closed  mouth ;  that  of  the  left  ventricle  will  be 
found  by  adding  0,44  c,  or  1°  F.,  to  the  degree 
indicated. 

Relations  in  point  of  temperature  between 
external  parts. — We  have  only  data  for  insti- 
tuting comparisons  in  regard  to  the  hand, 
the  axilla,  the  groin,  and  the  feet  among  the 
external  parts  of  the  body.  In  a  moderate 
summer-heat  die  hand  appears  to  be  the  part 
which  is  most  susceptible  of  showing  a  high, 
the  feet  the  parts  most  susceptible  of  exhibiting 
a  low  temperature.  The  axilla  and  groin  gene- 
rally exhibit  nearly  the  same  degree  of  tempe- 
rature; and  the  amount  in  which  they  differ  in 
this  particular  from  the  mouth  may  be  stated  at 
about  1°,  75. 

When  we  direct  our  inquiries  with  a  view  to 
ascertaining  any  general  relation  in  the  tempe- 
ratures of  different  parts  of  the  body,  whether 
external  or  internal,  we  soon  discover,  as  has 
been  already  stated,  that  this  has  no  connexion 
of  an  inverse  kind  with  their  distance  from  the 
heart.  At  the  same  time  there  is  a  general 
condition  discovered  influencing  the  tempera- 
ture of  the  different  parts.  This  is  their  situa- 
tion in  reference  to  the  surface  or  inside  of  the 
body.  The  temperature  is  higher,  for  instance, 
within  the  trunk  than  on  its  outside.  What- 
ever other  reason  may  be  assigned  for  this, 
there  is  one  which  is  purely  physical,  that  must 
influence  it  powerfully.  It  is  obvious  that  the 
surface  of  the  body  and  limbs  must  cool  much 
more  rapidly  than  the  interior  of  the  body.  So 
that,  supposing  the  temperature  at  first  to  be 
every  where  uniform,  the  difference  in  the  rate 
of  cooling  would  very  soon  suffice  to  cause  a 
notable  reduction  on  the  exterior  beyond  that 
which  took  place  in  the  interior  of  the  body. 
This  cause,  however,  can  only  be  charged  with 
its  own  share  of  influence ;  there  are  others 
which  must  act  with  considerable  effect,  and 
among  these  especially  the  one  upon  which  the 
production  of  heat  depends.  We  have  seen 
that  the  condition  of  the  functions  of  nutrition 
most  closely  in  relation  with  animal  heat  was 
connected  with  the  arterial  blood.  Now  inas- 
much as  the  arterial  blood  is  that  which  is  most 
intimately  connected  with  the  production  of 
caloric  among  animals,  we  might  fairly  expect 
that  the  temperature  generally  would  be  rather 
above  that  of  the  venous  blood.  And  we  have 
seen  that  there  was  actually  a  difference  be- 
tween the  temperatures  of  the  two  ventricles, 
that  of  the  left  being  the  higher.  Experiment 
has  also  shown  that  there  was  a  corresponding 
difference  in  the  temperatures  of  the  two  kinds 
of  blood  circulating  in  the  arteries  and  veins  ; 
arterial  blood  is  actually  higher  in  temperature 
than  venous  blood  to  the  extent  of  a  degree  of 
Fahrenheit's  scale.  We  shall  add  here,  and  in 
conformity  with  the  same  principle,  that  it  is 
to  this  difference  of  temperature  of  the  two 
kinds  of  blood  that  the  difference  in  the  tempe- 
rature of  the  right  and  left  ventricle  of  the  heart 
is  owing.    We  need  not  be  hindered  in  adopt- 


ing this  conclusion  from  the  circumstance  of 
the  blood  of  either  ventricle  being  found  in  a 
slight  degree  inferior  in  temperature  to  the  ven- 
tricle itself,  inasmuch  as  the  blood  abstracted 
from  the  canals  that  contain  it,  and  exposed  to 
the  air,  begins  to  evaporate,  and  loses  heat  ra- 
pidly. Nevertheless  it  is  not  demonstrated 
that  the  difference  in  temperature  of  the  blood 
out  of  and  of  the  blood  in  the  ventricles  of  the 
heart  depends  on  this  cause.  There  may  be 
another  at  work ;  the  influence  of  muscular 
contraction  for  instance,  a  point  which  we  shall 
examine  generally  by-and-bye.  New  means  of 
estimating  variations  of  temperature  have  been 
lately  discovered,  by  which  changes  that  en- 
tirely escaped  us  as  judged  of  by  the  thermo- 
meter are  made  abundantly  obvious;  by  which, 
indeed,  the  temperature  of  parts  inaccessible  in 
their  natural  and  normal  condition  to  the  ther- 
mometer are  now  investigated  without  diffi- 
culty. In  using  the  thermometer  as  the  means 
of  estimating  temperature,  it  is  evident  that 
this  instrument  could  not  be  introduced  into 
the  external  parts  without  injuring  the  tissues, 
without  incisions,  &c,  which  would  necessarily 
alter  them  materially,  and  produce  so  much  dis- 
turbance in  their  functions,  that  an  increase  or 
diminution  of  temperature  must  almost  neces- 
sarily have  been  the  consequence.  The  ther- 
mometer, besides,  however  small  its  dimen- 
sions, has  the  inconvenience  of  always  either 
absorbing  or  giving  out  a  considerable  quantity 
of  heat  according  to  circumstances,  before  it 
gets  into  equilibrium  with  the  parts  with  which 
it  is  brought  into  contact.  A  necessary  fall  or 
rise  in  the  absolute  temperature  of  these  parts 
is  the  natural  consequence  of  this.  Further, 
the  thermometer  is  incapable  of  showing  sudden 
variations  in  temperature;  several  minutes  must 
always  elapse  before  it  gets  into  a  state  of  equi- 
librium in  regard  to  temperature  with  the  parts 
or  medium  surrounding  it.  If  a  thermometer, 
for  instance,  be  placed  in  the  mouth,  three  or 
four  minutes  must  elapse  before  it  will  cease  to 
show  any  increase  of  temperature.  Now  if  any 
calorific  phenomena  of  short  duration  were  de- 
veloped in  that  time,  it  is  evident  that  all  idea 
of  their  occurrence  would  escape  us. 

These  considerations  led  to  the  adoption  of 
thermo-electrical  means  by  Messrs.  Becquerel 
and  Breschet.  The  processes  they  employed 
in  procuring  indications  of  temperature  were 
the  following.  The  only  means  we  have  of  pe- 
netrating into  the  interior  of  organs  without  in- 
jury is  to  make  use  of  a  needle  similar  to  that 
employed  in  acupuncture.  Now  it  is  easy  to 
arrange  this  needle  so  as  to  obtain  thermo-elec- 
tric indications,  which  proclaim  immediately 
and  with  the  greatest  precision  the  temperature 
of  the  part  or  medium  with  which  the  point 
happens  to  be  in  contact.  It  is  enough  to 
compose  this  needle  of  two  others  in  metal, 
two  of  the  extremities  of  which  are  soldered 
together  in  a  few  points  only,  whilst  the  other 
two  are  placed  in  communication  with  one  of 
the  extremities  of  the  wire  of  an  excellent  ther- 
mo-electric multiplier.  The  slightest  changes 
of  temperature  at  the  points  of  junction  give 
origin  to  an  electrical  current,  which,  iu  reacting 


656 


ANIMAL  HEAT. 


on  the  magnetic  needle,  causes  it  to  deviate  by 
a  certain  number  of  degrees,  which  conse- 
quently become  indices  of  the  temperature  of 
the  point  of  the  needle,  and  therefore  of  the 
medium  in  which  it  is  placed.  The  multiplier 
ought  to  be  so  sensitive  as  to  show  a  deviation 
of  one  degree  of  the  magnetic  needle  for  each 
one-tenth  of  a  degree  of  temperature  as  mea- 
sured by  the  centigrade  scale,  an  amount  of 
temperature  made  sensible  by  the  union  of  the 
two  ends  of  the  wire  which  forms  its  circuit 
with  an  iron  wire  soldered  by  its  ends. 

So  much  for  the  general  principle  upon 
which  and  by  which  the  inquiries  of  Messrs. 
Becquerel  and  Breschet  were  conducted.  As 
to  all  the  precautions  necessary  to  render  re- 
searches of  the  kind  fruitful,  as  these  are  nume- 
rous, we  beg  to  refer  for  an  account  of  them  to 
the  memoir  of  the  authors  themselves. 

Difference  of  temperature  according  to  the 
depth. — By  the  means  contrived  by  Becquerel 
and  Breschet  the  temperature  of  the  calf  of  the 
leg  at  the  depth  of  four  centimetres  from  the 
surface  was  found  to  be  36°,75  (about  98°  F.), 
and  at  one  centimetre  34°,50  (about  94°  F.), 
a  difference  of  2°,25  (4°  F.).  In  the  chest  the 
temperature  at  the  depth  of  the  pectoralis 
major,  compared  with  that  of  the  superficial 
cellular  tissue  at  the  depth  of  one  centimetre, 
showed  a  corresponding  difference;  the  deeper 
parts  were  2°,25  (about  4°  F.)  higher  than  the 
more  superficial.  In  seven  experiments  made 
on  the  arm  the  mean  difference  of  temperature 
between  the  deeper  strata  of  the  biceps  and  the 
superficial  cellular  tissue  over  the  same  muscle 
amounted  to  1°,59  c.  in  favour  of  the  deeper 
parts. 

The  next  point  of  inquiry  was  to  know  whether 
it  was  enough  to  penetrate  to  the  depth  of  three 
or  four  centimetres  into  the  trunk  and  limbs  to 
attain  the  points  of  highest  temperature  in 
these  parts.  With  this  view  we  have  compared 
the  observations  made  by  the  authors  mention- 
ed, in  the  same  individual,  with  regard  to  the 
temperature  of  the  mouth  and  of  the  biceps 
muscle,  and  we  find  that  the  mean  temperature 
of  the  mouth  was  36°,89,  that  of  the  biceps 
36°,88,  (about  98°  F.), — a  result  which  may  be 
called  identical  with  the  former.  The  mean  of 
seven  other  experiments,  however,  shows  the 
relation  of  36°,89  c.  for  the  mouth,  of  36°, 75  c. 
for  the  biceps ;  the  difference  here  is  evidently 
in  favour  of  the  mouth.  It  were  to  be  wished 
that  inquiries  in  this  direction  were  multiplied 
in  order  that  absolute  certainty  may  yet  be 
attained. 

In  the  preceding  experiments,  in  penetrating 
to  different  depths,  the  nature  of  the  tissues  at- 
tained also  differs,  a  circumstance  which  must 
tend  to  complicate  the  results ;  for  it  is  possi- 
ble that  the  nature  of  the  tissue  may  have  some 
influence  on  the  evolution  of  heat.  This  is 
even  an  inference  which  we  should  deduce 
from  the  principles  already  established,  were  it 
merely  in  consideration  of  the  different  quanti- 
ties of  blood  they  contain.  And  this  conclu- 
sion is  even  confirmed  by  the  experiments  of 
the  parties  mentioned  ;  for  on  compressing  the 
humeral  artery  strongly,  the  motion  of  the  nee- 


dle immediately  announced  a  fall  of  tempera- 
ture to  the  extent  of  several  tenths  of  a  degree. 
This  experiment  is  interesting  from  the  rapidity 
and  precision  of  the  effect.  There  are  other 
cases  well  known  by  which  we  are  led  to  a 
corresponding  conclusion  ;  but  nowhere  else  is 
the  fact  seen  in  so  simple  a  guise,  or  in  so  ma- 
nifest a  relation  of  cause  and  effect.  In  opera- 
tions for  aneurism,  indeed,  and  other  cases  re- 
quiring the  ligature  of  a  large  artery,  the  tem- 
perature of  the  parts  supplied  by  the  vessel 
tied  falls  so  low  as  to  require  to  be  supported 
by  artificial  warmth  ;  but  then  a  severe  and 
bloody  operation  has  been  performed  by  which 
the  conditions  are  complicated.  In  the  expe- 
riment mentioned,  on  the  contrary,  nothing 
occurs  to  disturb  the  state  of  the  economy  ;  the 
effect  instantly  follows  the  cause,  and  its 
amount  is  even  at  the  same  moment  ascer- 
tained. 

Seeing,  then,  that  in  the  same  tissue  the  freer 
or  more  interrupted  access  of  arterial  blood 
causes  the  temperature  to  vary,  it  is  fair  to  infer 
that  the  relative  freedom  of  access  or  quantity 
of  this  fluid  vvhicli  circulates  through  other 
tissues  should  have  an  influence  upon  their 
temperature  ;  in  other  words,  that  tissues  differ 
in  their  power  of  producing  heat  according  to 
the  quantity  of  blood  which  circulates  through 
them.  We  can  scarcely  doubt,  therefore,  but 
that  the  differences  of  temperature  observed  be- 
tween the  deeper  and  more  superficial  parts  are 
complicated  by  the  mere  fact  of  difference  of 
distance  from  the  surface,  and  also  by  the  cir- 
cumstance of  difference  of  tissue.  The  super- 
ficial layer  in  the  preceding  experiments  was 
cellular  membrane  ;  the  deeper  layer  was  mus- 
cular. But  the  muscles  receive  a  much  larger 
quantity  of  blood  than  the  cellular  membrane, 
and  their  temperature,  from  this  circumstance 
alone,  ought  to  be  higher.* 

*  [Messrs.  Becquerel  and  Breschet,  in  a  memoir 
lately  read  before  the  Royal  Academy  of  Sciences, 
(Ann.  des  Sciences  Nat.  Mai  1838,)  entitled, 
"  Further  Observations  on  the  Temperature  of  the 
Tissues  of  the  body  of  Man  and  the  lower  Animals, 
as  ascertained  by  means  of  thermo-electric  effects," 
have  made  a  few  additional  observations  which  de- 
serve quotation  in  this  place.  The  temperature  of 
the  mouth  being  used  as  the  standard  of  compari- 
son, the  temperature  of  the  biceps  muscle  was 
found  to  be  but  36°,  20  c,  instead  of  3b'°,  60, 
which  was  the  term  derived  from  previous  experi- 
ments, and  to  fall  short  of  the  temperature  of  the 
mouth  by  as  many  as  4°  c.  (above  7°  F.) 

In  making  experiments  upon  the  influence  of 
the  temperature  of  surrounding  media  upon  that  of 
the  tissues,  Messrs.  Becquerel  and  Breschet  intro- 
duced the  needles  of  their  thermo -electrical  appara- 
tus into  the  biceps  muscles  of  two  young  and 
healthy  individuals,  the  air  at  the  time  marking 
16°  c.  (61°F. ).  The  magnetic  needle  did  not  deviate 
in  the  least ;  so  that  the  two  muscles  possessed 
precisely  the  same  temperature.  One  of  the  arms 
was  now  immersed  for  a  quarter  of  an  hour  in  water 
of  the  temperature  successively  of  10°,  8°,  6°,  and 
0°-  c.  (50°,  47°,  43°,  and  32°  F.).  The  deviation  of 
the  needle  did  not  amount  to  more  than  two  degrees 
of  its  scale  in  favour  of  the  muscle  of  the  arm  which 
was  not  plunged  into  the  water.  The  partial  cold 
hath,  consequently,  had  only  caused  a  depression 
of  temperature  to  the  extent  of  about  one-fifth  of  a 
degree  c.   The  arm  being  now  plunged  into  water 


ANIMAL  HEAT. 


657 


We  might  even  deduce  from  this  a  fact  of 
great  importance  in  the  animal  economy,  viz. 
that  muscular  contraction  is  a  cause  of  heat,  in- 
asmuch as  it  determines  the  afflux  of  blood  to- 
wards the  muscles  themselves  as  well  as  to- 
wards all  the  surrounding  parts.  It  is  very 
difficult  to  conceive  an  occasion  of  verifying 
this  position  in  its  simplicity  ;  for  bodily  efforts, 
in  which  the  skin  becomes  red  and  injected, 
are  always  accompanied  with  some  disturbance 
of  the  respiration  and  motion  of  the  blood.  We 
have,  however,  had  an  opportunity  of  seeing 
one  individual  of  athletic  powers,  who,  by 
merely  throwing  the  muscles  of  the  fore-arm 
into  strong  contraction,  could  cause  the  integu- 
ments of  the  forearm  to  become  red.  During 
the  act  of  muscular  contraction  consequently, 
the  temperatuie  must  have  a  tendency  to  rise. 

at  the  temperature  of  42°  c.  (108°  F.)  for  fifteen 
minutes,  the  temperature  of  the  mu-cle  as  compared 
with  that  of  the  other  was  found  to  have  increased  one  - 
fifth  of  a  degree.  When  the  whole  body  was  plunged 
in  a  hot  hath  at  the  temperature  of  49°  c.  (120p  F. ), 
the  deviation  of  the  needle  varied  from  12°  to  13° 
and  14°  of  its  scale,  which  indicated  a  rise  in  tem- 
perature of  from  one-fifth  to  two-fifths  of  a  degree  c. 
The  pulse  was  increased  to  112  beats  per  minute, 
the  body  being  immersed  in  this  bath.  The  tempe- 
rature of  the  body  before  immersion  was  36°,  70  c. 
(98°  F.),  a  degree  to  which  it  immediately  returned 
after  coming  out  of  the  bath.  In  trying  experi- 
ments of  the  same  kind  subsequently,  but  with 
baths  at  a  somewhat  lower  temperature,  namely, 
42°,  50  (109°  F.),  no  rise  of  temperature  was  indi- 
cated. The  immersion  in  these  cases  was  not  con- 
tinued for  more  than  twenty  minutes.  Had  it  been 
protracted  for  a  longer  time,  the  result  might  have 
been  different.  When  a  dog,  whose  muscles  indi- 
cated a  temperature  of  33°,  50  (102°  F.),  was 
plunged  into  a  hot  bath  at  49°  c.  (120°  F.),  the 
temperature  rose  rapidly  by  half  a  degree,  a  degree, 
and  finally  two  degrees  c.  ;  but  the  animal  had  be- 
come so  much  enraged  that  it  was  found  necessary 
to  take  him  out  of  the  water.  The  needle  of  the 
apparatus  being  passed  into  the  chest,  a  like  rise  in 
temperature  was  indicated  ;  but  the  rise  in  tempe- 
rature was  found  to  happen  principally  when  the 
animal  became  angry  ;  and  it  is  doubtful  how  far 
the  slate  of  exasperation  influenced  the  results. 

In  one  experiment  the  one  needle  being  passed 
into  the  biceps  muscle  of  a  young  man,  the  other 
into  the  long  radial  supinator  of  a  man  aged  forty- 
five,  no  sensible  deviation  of  the  magnetic  indicator 
ensued.  A  vein  was  then  opened  in  one  of  the 
arms,  as  near  as  possible  to  the  point  at  which  the 
needle  had  been  introduced,  but  no  change  of  tem- 
perature took  place  either  during  or  after  the  flow 
of  the  blood.  The  common  iliac  artery  of  a  dog 
was  now  isolated  and  a  ligature  thrown  loosely 
round  it,  so  that  it  could  be  compressed  or  left  free 
at  pleasure,  and  one  of  the  needles  of  the  apparatus 
plunged  into  the  fleshy  part  of  the  thigh.  The 
current  of  blood  having  been  interrupted,  the  tem- 
perature of  the  limb  began  to  fall,  but  not  until 
after  the  lapse  of  an  interval  of  twenty  minutes, 
when  it  still  amounted  to  no  more  than  about  half  a 
degree  c.  The  free  access  of  blood  having  been 
restored,  the  temperature  soon  rose  again  to  the 
normal  point.  The  effect,  though  trifling  in  this 
case, — and  the  same  experiment  was  repeated  several 
times  always  with  the  same  result, —is  still  suffi- 
cient to  show  that  the  arterial  blood  exerts  a  direct 
influence  upon  the  temperature  of  the  animal  tis- 
sues. The  effect,  however,  it  is  obvious  from  the 
time  which  elapses  before  it  becomes  apparent,  is 
to  be'attributed,  not  to  the  blood  which  is  circulating 
in  the  trunks  and  branches  of  the  vessels,  but  to 
that  which  is  contained  in  the  vascular  rete.— Ed.] 
vol.  ji. 


This  fact  is  demonstrated  in  the  most  satis- 
factory manner  by  the  delicate  experiments  of 
Messrs.  Becquerel  and  Breschet  as  follows. 
When  one  of  the  joinings  ( soudures )  is  kept 
uniformly  at  a  temperature  of  36°  c.  (97°  F.). 
and  the  other  is  inserted  into  the  biceps  muscle 
with  the  arm  extended,  the  magnetic  needle 
was  found  to  deviate  about  .10  of  a  degree. 
On  the  arm  being  bent,  however,  the  amount 
of  deviation  was  observed  to  increase  suddenly 
to  the  extent  of  from  one  to  two  degrees. 
Waiting  till  the  oscillation  of  the  needle  and 
its  return  are  completed,  if  the  arm  be  bent 
anew  so  as  to  give  a  fresh  impulse  to  the  needle 
for  several  times  in  succession,  a  deviation  of 
fifteen  degrees  is  obtained  at  length,  equivalent 
to  a  difference  of  five  degrees  in  comparison 
with  the  original  deviation,  and  corresponding 
to  an  increase  of  about  half  a  degree  of  tem- 
perature as  measured  by  the  centigrade  scale. 
If  the  needle  be  inserted  into  the  biceps,  and 
the  arm  be  used  in  the  action  of  sawing  for 
about  five  minutes,  the  temperature  is  observed 
to  rise  considerably,  sometimes  to  the  amount 
of  a  degree  centigrade. 

In  these  researches,  then,  we  have  evidence  of 
facts  of  which  we  could  not  have  acquired  any 
precise  information  by  our  ordinary  means  of 
investigation.  Every  one,  indeed,  knows  that 
exercise  warms  the  body  ;  but  every  one  also 
sees  that  in  producing  this  effect,  besides  the 
contraction  of  the  voluntary  muscles,  exercise 
is  accompanied  by  an  acceleration  in  the  mo- 
tions of  the  heart  and  organs  of  respiration. 
In  this  simultaneous  concurrence  of  a  variety 
of  phenomena,  it  was  impossible  to  distin- 
guish the  share  which  each  had  in  the  general 
result.  Such  an  analysis  could  only  be  made 
by  an  experiment  of  the  delicate  and  ingenious 
description  of  that  which  has  been  detailed. 

It  would  appear  that  it  is  by  the  repetition 
of  the  muscular  contraction  after  each  relaxa- 
tion that  the  highest  evolution  of  heat  is  ob- 
tained, each  contraction  producing  a  slight  in- 
crease of  temperature,  which,  with  the  addition 
of  that  which  follows,  mounts  to  a  certain 
limited  point  which  it  cannot  pass.  Let  us 
remark,  however,  that  the  mere  persistence  of  a 
primary  contraction  ought  to  have  the  effect  of 
causing  or  maintaining  a  temperature  higher 
than  that  which  is  evolved  by  a  contraction 
followed  immediately  by  relaxation  ;  indeed  it 
is  now  known  that  a  permanent  muscular  con- 
traction is  but  a  series  and  succession  of  smaller 
and  imperceptible  contractions,  following  each 
other  with  extreme  rapidity. 

It  were  well  to  observe  here,  that  neighbour- 
ing parts  must  increase  in  temperature  at  the 
same  time  much  less  in  consequence  of  the 
direct  communication  of  heat  in  virtue  of  con- 
tiguity than  by  the  afflux  of  blood,  which, 
transmitted  to  the  muscles  in  larger  quantity, 
must  also  be  more  copiously  than  usual  dis- 
tributed to  adjacent  tissues.  The  relaxation  of 
the  muscles  ought,  on  the  other  hand,  to  have 
a  tendency  to  reduce  the  temperature,  and  this 
by  so  much  the  more  as  the  relaxation  is  more 
complete.  From  all  this  it  follows  that  the 
attitude  and  state  of  the  body  will  be  favours- 

2  x 


658 


ANIMAL  HEAT. 


ble  to  cooling  in  the  ratio  of  the  general  relax- 
ation of  the  muscles,  and  of  the  degree  in  which 
each  of  them  in  particular  is  in  a  state  of  qui- 
escence. This  is  what  happens  in  sleep,  of 
which  we  shall  speak  by-and-bye. 

In  the  rise  of  temperature  observed  along 
with  muscular  contraction,  we  have  in  the  first 
place  only  considered  the  action  of  the  blood ; 
but  neither  contraction  of  the  muscles  nor  the 
afflux  of  a  larger  quantity  of  blood  could  take 
place  without  the  nervous  influence;  for  it  is 
the  will  which  determines  the  muscular  contrac- 
tion, and  the  will  only  acts  through  the  me- 
dium of  the  nerves  which  are  distributed 
to  the  muscles.  From  this  consideration  it 
follows  equally  as  from  general  relations  pre- 
viously exposed,  that  whatever  lessens  the 
nervous  influence  will  likewise  tend  to  reduce 
the  temperature.  Here  we  are,  then,  reverting 
to  the  two  general  conditions  which  we  had 
already  found  to  be  the  most  influential  in  ca- 
lorification, namely,  the  arterial  blood  and  the 
nervous  system. 

This  examination  of  the  relative  tempera- 
tures of  the  different  parts  of  the  body  has  led 
us,  by  the  immediate  comparison  of  the  super- 
ficial and  deeper  layers,  to  the  consideration  of 
the 

Influence  of  external  temperature. — An  in- 
ert or  inanimate  body  of  higher  temperature 
than  the  surrounding  medium  will  of  neces- 
sity cool  faster  at  its  surface  than  in  its  internal 
parts.  A  living  body,  likewise,  having  within 
itself  a  permanent  source  of  heat,  which  we 
shall  suppose  equally  distributed  through  it, 
will  lose  more  caloric  from  its  surface  than  from 
its  interior.  This  loss  will  become  apparent 
by  the  cooling  of  the  surface,  so  long  as  the 
source  of  heat  remains  everywhere  equal.  If, 
on  the  contrary,  it  be  unequally  distributed, 
if  it  be  greater  towards  the  surface,  so 
as  to  compensate  the  greater  loss  which 
takes  place  there,  the  surface  will  have 
the  same  temperature  as  the  interior.  Without 
such  a  supposition  it  were  necessary  that  the 
surface  of  the  body  should  be  lower  in  tem- 
perature than  the  interior.  This,  indeed,  is  the 
actual  state  of  the  case.  The  external  parts  of 
living  bodies  are  colder  than  the  internal  parts, 
because  on  the  one  hand  the  focus  of  heat  is 
less,  by  reason  of  the  nature  of  the  component 
tissues,  and  on  the  other  because  the  loss  of 
heat  there  is  greater.  When  the  external  tem- 
perature falls,  then  the  outer  layers  will  tend  to 
sink  in  temperature  also,  and  will,  in  fact,  sink 
so  long  as  the  internal  source  of  heat  remains 
the  same.  This  partial  refrigeration  will  be 
propagated  internally,  and  the  general  tem- 
perature will  be  lessened  unless  the  economy 
provides  against  such  an  occurrence  by  an  in- 
crease of  activity  in  its  calorific  powers. 

The  same  reasoning  is  applicable  to  move- 
ments of  the  temperature  of  bodies  under 
the  influence  of  that  of  the  air.  Heat  will  be 
propagated  from  without  inwards,  and  will 
raise  the  general  temperature  of  the  body,  un- 
less it  lessens  in  the  same  proportion  as  it  re- 
ceives external  temperature,  that  which  it  pro- 
duces of  itself. 


The  consideration  of  the  changes  in  the  in- 
tensity of  the  internal  focus,  in  other  words,  in 
the  faculty  of  producing  heat,  and  of  the  con- 
ditions which  determine  these,  is  the  most  im- 
portant point  of  all  in  the  study  of  animal 
heat,  on  account  of  the  multitude  of  practical 
applications  which  result  from  it. 

It  is  obvious  from  what  has  already  been 
said  that  there  is  an  essential  difference  between 
inert  or  inanimate  and  animate  bodies  subjected 
to  the  influence  of  external  temperature.  The 
temperature  of  the  former  depends  solely  on 
the  general  laws  which  regulate  the  propaga- 
tion of  heat,  whilst  the  temperature  of  the 
others  is  subjected  to  the  influence  of  another 
element,  namely,  the  heat  which  they  them- 
selves produce.  Did  this  element  continue 
fixed  and  invariable,  it  would  be  possible  to 
determine,  by  the  application  of  the  known 
data  of  physics,  what  must  be  the  temperature 
of  a  living  body  under  the  influence  of  a  given 
external  temperature.  But  if  this  element 
varies,  and  the  laws  according  to  which  it 
varies  are  unknown,  it  becomes  impossible  to 
predict  in  what  manner  the  temperature  of  an 
animal  will  be  affected  by  that  of  the  medium  in 
which  it  lives.  It  is  only  very  lately,  therefore, 
that  the  temperature  of  man  and  warm-blooded 
animals,  with  the  exception  of  those  that  hy- 
bernate,  has  been  believed  to  continue  unaf- 
fected in  the  midst  of  extensive  variations  in 
the  temperature  of  the  surrounding  atmosphere. 

Variations  in  the  temperature  of  animal 
bodies  in  a  state  of  health,  independently  of 
external  temperature. — Duly  to  appreciate  the 
inquiries  that  have  been  instituted  in  this  direc- 
tion, the  first  question  to  be  asked  is,  whether 
or  not  the  temperature  of  the  body  presents 
variations,  although  external  conditions  continue 
the  same,  or  nearly  the  same  ?  The  answer 
here  must  be  in  the  affirmative  :  the  body 
varies  in  temperature  at  different  times,  exter- 
nal circumstances  as  to  temperature  continuing 
nearly  the  same.  This  is  apparent  in  the  ob- 
servations of  Dr.  John  Davy  instituted  with 
another  view,  but  quite  available  here.  We 
perceive  that  the  individual  designated  No.  1, 
having  a  temperature  of  37°  8  (100°  F.),  when 
the  air  was  at  26°,  4  (79°  F.),  had  a  tempera- 
ture of  only  37°,  5  (99°,  75  F.)  when  the  air 
was  at  26°,  7  (80°  F.),  that  is  to  say,  the  same 
person  showed  a  third  of  a  degree  c.  less  of 
temperature,  when  the  air,  instead  of  becoming 
colder,  had  actually  become  warmer  in  the 
same  proportion.  The  temperature  of  No.  3 
was  37°,  2  (99°  F.),  when  the  air  marked  25°, 
5  (78°  F.),  and  on  another  occasion  it  was  only 
36°,  9  (98°  F.),  when  the  air  was  26°  (79°  F.)  ; 
in  other  words,  the  temperature  of  the  body, 
instead  of  rising,  had  actually  fallen  by  0°,  7 
cent.,  when  that  of  the  external  air  had  risen 
0°,  9  cent. 

Influence  of  the  natural  temperature  of  the 
air  on  that  of  the  body. — It  must  be  obvious 
from  the  facts  of  the  last  paragraph  that  the 
influence  of  external  temperature  cannot  be 
appreciated  without  having  recourse  to  means 
of  observation  calculated  to  make  variations 
dependent  on  foreign  causes  to  disappear. 


ANIMAL  HEAT. 


659 


To  render  the  comparison  of  the  mean  sums 
obtained  more  certain,  we  shall  confine  our- 
selves to  the  observations  of  the  inquirer  just 
quoted,  made  upon  the  same  individuals  at 
different  temperatures.  The  following  series  is 
after  the  data  supplied  by  Dr.  Davy  : — 

Temperature  of  the  air.    Mean  temperature  of  Jive 

men. 

15°,  5  (60°  F  )   36°,  85  (93°  F.) 

25°,  5  (78°  F.)  37°,  16  (99°  F.) 

26°,  4  (79°  F.)  37°,  32  (99°  5,  F.) 

26°,  7  (80°  F.)  37°,  58  (100°  F.) 

27°,  8  (82°  F.)  37°,  70  (100°  5,  F.) 

It  is  apparent  that  these  differences,  even  the 
extremes,  do  not  surpass  the  limits  of  the 
variations  which  the  same  individual  exhibits, 
or  may  experience  spontaneously  under  the 
same  temperature  of  the  air.  But  when  it  is  con- 
sidered that  these  differences  are  mean  results, 
forming  a  series  increasing  with  the  rise  of  the 
external  temperature,  it  is  impossible  to  doubt 
of  their  standing  in  the  relation  to  one  another 
of  cause  and  effect.  If  this  dependence  and 
connection  actually  exists,  we  must  allow  that 
it  is  very  little  obvious  at  the  temperatures 
within  the  limits  of  which  these  observations 
were  made ;  for  whilst  the  temperature  of  the 
air  varied  to  the  extent  of  12°,  3  c  ,  the  changes 
in  the  mean  temperature  of  the  body  did  not 
exceed  0°,  9.  Such  slight  differences  being  apt 
to  leave  uncertainty  in  the  mind  as  to  the  cause 
producing  them,  we  shall  confirm  the  impres- 
sion they  are  nevertheless  calculated  to  make 
by  citing  others,  for  which  we  are  indebted  to 
Dr.  Reynaud,  surgeon  of  the  corvette  La 
Chevrette,  in  a  voyage  of  discovery  in  the 
Asiatic  seas  undertaken  in  the  year  1827.  The 
instruments  used  were  furnished  by  the  best 
makers  of  Paris,  and  were  compared  by  M. 
Arago  with  those  of  the  Observatory  ;  and  the 
observations  were  made  conjointly  with  M. 
Blosville,  lieutenant  of  the  vessel,  charged  by 
the  Academy  of  Sciences  of  Paris  with  various 
researches  in  natural  philosophy. 
Mean  temperature  of  the' 

body  deduced  from  ob- 
servations four  times  re- 
peated upon  each  of  eight 

men,  under  the  torrid 

zone,  the  external  tempe- 
rature varying  from  26° 

to  30°  c.  (79°,  86°  F-X 
Mean  temperature  of  the~\ 

same  eight  men  observed  | 

three  times  in  the  tern-  I  . 

perate  zone,  the  external  j 

temperature  varying  from 

12°  to  17°  (53°  to  62°  F.)_ 

These  results  confirm  those  of  Dr.  Davy  by 
so  much  the  more  as  they  were  made  within 
the  same  limits  of  external  temperature.  The 
mean  rise  of  the  temperature  of  the  body  un- 
der the  influence  of  that  of  the  air  is  also 
equally  confirmed;  but  the  amount  is  still  less 
than  as  given  by  the  English  observer. 

It  seems  impossible,  then,  to  doubt  that  the 
natural  variations  in  the  temperature  of  the  air 
affect  that  of  the  body  of  man  ;  but  this  is 
only  in  a  very  trifling  degree,  at  least  within  the 


>-37°,  58  (100  F.) 


37°,  11  (99°  F.) 


limits  of  temperature  in  which  any  extant  ob- 
servations have  been  made.  It  is  greatly  to  be 
regretted  that  neither  of  the  observers  quoted 
had  opportunities  of  ascertaining  the  effects  of 
much  lower  temperatures  than  those  they  have 
given.  There  are,  it  is  true,  many  isolated  ob- 
servations made  by  voyagers  in  the  Arctic 
regions,  both  upon  animals  and  man,  and 
although  conducted  in  no  regular  series,  or  as 
points  of  comparison  with  one  another, 
they  still  lead  to  the  same  general  result, 
namely,  that  great  differences  in  the  tempera- 
ture of  the  air  cause  slight  differences  in  the 
temperature  of  the  body  of  animals.  Thus,  in 
the  voyage  of  Captain  Parry  it  was  observed 
that  the  temperature  of  the  Mammalia  was  very 
high.  With  the  external  thermometer  at 
—  29°,  4  (—  21°,  F.),  the  temperature  of  the 
white  hare  was  +  38°,  3  (101°  F.).  With  the 
thermometer  at  —  32°,  8  (27°  F.),  the  tempe- 
rature of  a  wolf  was  -+-  40°,  5  (105  F.);  the 
temperature  of  the  Arctic  fox,  under  nearly  the 
same  circumstances,  namely,  when  the  thermo- 
meter was  standing  at  —  35°  ( — 31°  F.),  was 
as  high  as  +  41°  5  (107°  F.).  Similar  obser- 
vations have  since  been  made  in  the  same  high 
latitudes  upon  man. 

The  variations  in  the  temperature  of  warm- 
blooded animals  according  to  that  of  the  seasons 
has  been  studied  by  the  present  writer,  who  con- 
firms the  results  just  stated.  The  experiments 
of  the  writer  were  made  upon  a  great  num- 
ber of  sparrows  recently  taken  at  different 
seasons  of  the  year,  which  is  preferable  to 
keeping  these  creatures  in  captivity  for  any 
length  of  time.  The  mean  temperature  of 
these  birds  rose  progressively  from  the  depth 
of  winter  to  the  height  of  summer,  within  the 
limits  of  from  two  to  three  degrees  centigrade. 
The  observations  made  on  sparrows  exhibited 
the  greatest  differences.  In  the  month  of  Feb- 
ruary the  mean  temperature  of  these  birds  was 
found  to  be  40°,  8  (105°  F.)  ;  in  April  42° 
(108°  F.),  in  July  43°,  77  (111°  F.).  The 
temperature  from  this  time  began  to  decline, 
and  followed,  in  the  same  ratio  in  which  it  had 
increased,  the  sinking  temperature  of  the  year. 

Influence  of  media  upon  temperature. — The 
media  in  which  animals  live  do  not  act  solely 
in  the  ratio  of  their  temperature,  but  also  by 
virtue  of  the  intensity  of  their  cooling  or  heating 
power.  Thus  air  and  water  at  the  same 
degree  of  heat  will  have  a  very  different  influ- 
ence on  the  temperature  of  the  bodies  plunged 
in  them.  The  power  of  air  in  heating  or 
cooling  is  commonly  known  to  be  very  inferior 
to  that  of  water.  Bodies  acquire  or  lose  tem- 
perature much  more  slowly  in  air  than  in  water. 
A  water-bath  according  to  its  temperature  com- 
municates sensations  of  heat  or  cold  far  more 
rapidly  and  powerfully  than  an  air-bath. 
The  writer  and  M.  Centil  made  the  following 
experiment :— A  young  man  seventeen  years  of 
age,  of  strong  constitution  and  in  good  health, 
after  remaining  for  twenty  minutes  in  a  bath 
the  water  of  which  marked  13°  R.  (61°,  5  F.), 
whilst  the  air  was  14°,  R.  (63°  F.),  half  an 
hour  afterwards  was  found  to  have  lost  haM' a 
degree  of  his  original  heat  in  the  mouth  and 

2x2 


660 


ANIMAL  HEAT. 


hands,  and  a  degree  and  a  half  in  the  feet.  This 
temperature  of  the  air  may  be  regarded  as  a 
mean,  or  intermediate  between  heat  and  cold, 
and  may  be  termed  temperate  (61°  to  62°  F.). 
It  was  superior  to  that  of  the  water  by  a  degree 
R.,  and  yet  the  water  of  the  bath,  after  immersion 
in  it  for  no  longer  a  time  than  twenty  minutes, 
had  reduced  the  temperature  of  the  body 
according  to  its  parts  from  half  a  degree  to  a 
degree  and  a  half  R. 

Effects  of  external  temperature  upon  an 
isolated  part  of  the  body. — Under  this  head 
let  us  examine,  1st,  the  extent  of  the  effect,  and 
2nd,  its  influence  on  other  parts.  The  facts 
we  shall  borrow  from  the  researches  just 
quoted,  those  namely  of  myself  and  M. 
Centil.  The  hand,  at  29°  R.  (98°  F.)  having 
been  kept  immersed  in  a  tub  of  water  cooled 
down  to  +  4°  R.  (41°F.),  in  all  during  twenty 
minutes,  five  minutes  after  it  had  been  taken 
put  of  the  water,  marked  no  higher  a  tempera- 
ture than  10°  R.  (55°  F.)  This  experiment 
shows  how  rapid  and  extensive,  and  how  much 
beyond  what  could  have  been  anticipated,  may 
be  the  refrigerating  effects  of  cold  water  applied 
to  an  extremity.  Another  not  less  remarkable 
result  is  the  singular  slowness  with  which  the 
temperature  of  an  extremity  is  regained, 
although  exposed  to  the  gentle  warmth  of  the 
air.  The  hand  in  the  above  experiment,  after 
the  lapse  of  twenty-five  minutes  from  the  time 
it  was  removed  from  the  water,  was  still  no 
higher  than  16i°  R.  (69°  F.),  and  after  the 
expiration  of  an  hour  and  a  half  it  was  only 
24£°  R.  (87°  F.).  The  foot,  in  the  same  cir- 
cumstance-, gave  nearly  analogous  results. 

In  a  number  of  experiments  of  the  same 
nature  as  the  last,  where  one  hand  was  plunged 
in  water  cooled  down  by  ice,  the  other  hand, 
which  was  not  subjected  to  the  action  of  the  cold 
bath,  lost  nearly  5°  R.  in  temperature. 

It  is  therefore  apparent,  1st,  that  partial 
chills,  or  the  exposure  of  individual  parts  to 
low  temperatures,  may  be  and  are  felt  very 
extensively  even  when  the  cold  is  not  very 
severe  ;  2nd,  that  the  chilling  of  a  single  part, 
such  as  the  hand  or  the  foot,  may  cause  a  loss  of 
temperature  in  all  the  other  parts  of  the  body, 
even  far  beyond  what  could  have  been  pre- 
sumed as  likely  or  possible.  These  facts  give 
a  key  to  the  right  understanding  of  the  immense 
influence  which  partial  chills  are  capable  of 
exercising  on  the  state  of  the  general  health 

Of  the  effects  of  partial  heating. — The  hand 
being  immersed  in  water  heated  to  the  tem- 
perature of  34°  R.  (109°  F.),rose  one  degree  of 
the  same  scale,  and  the  temperature  of  other 
remote  parts  not  immediately  exposed  to  the 
influence  of  heat  were  found  to  have  risen  in  a 
corresponding  degree.  Whence  follows  this 
axiom, — that  we  cannot  either  raise  or  lower 
the  temperature  of  any  one  part  of  the  bodu 
without  all  the  other  parts  of  the  frame  being 
affected,  and  suffering  a  corresponding  rise  or 
Jail  in  temperature,  more  or  less  according 
to  circumstances.  We  may  further  presume 
from  the  comparison  of  these  facts,  that  the 
body  and  its  parts  are  liable  to  variations  of 
temperature  towards  either  extremity  of  the 


scale  from  the  mean,  much  more  considerable 
than  are  generally  imagined.  This  latter  fact 
will  appear  very  evidently  from  the  other 
inquiries  which  are  now  to  engage  our  atten- 
tion. 

Effects  of  an  excessively  high  or  excessively 
low  external  temperature  upon  the  temperature 
of  the  body. — Hitherto  we  have  only  considered 
the  changes  in  the  temperature  of  the  body  pro- 
duced by  moderate  degrees  of  external  heat  and 
cold.    We  now  pass  on  to  the  examination  of 
the  effects  caused  by  extreme  external  tempera- 
tures, and  first  of  those  that  follow  from 
excessive  heat;  designating  by  excessive  heat 
any  temperature  that   surpasses  that  of  the 
human    body.     On   a  summer's  day,  the 
temperature    of    the  air    being   37°,  77  c. 
(100°  F.),  Franklin  observed  that  the  tempera- 
ture of  his  own  body  was  nearly  35°,  55  c. 
(96°  F.).    This  fact,  which  is  perhaps  the  first 
of  the  kind  noted,  is  highly  deserving  of  atten- 
tion.    It  proves  that  man,  and  by  analogy 
otheranimals,havea  power  of  keeping  their  tem- 
perature inferior  to  that  of  the  air.  As  in  the  ob- 
servation quoted  there  is  no  means  of  knowing 
what  effect  the  excessive  external  temperature 
had  produced  upon  the  temperature  of  the 
observer,  recourse  must  be  had  to  other  facts. 
In  numerous  experiments  made  in  England  by 
Dr.  Fordyce  and  his  friends,  and  subsequently 
by  Dr.  Dobson,  in  which  these  experimenters 
exposed  themselves  to  very  high  temperatures, 
which  on  some   occasions  exceeded  that  of 
boiling  water,  the  heat  of  the  body  was  never 
observed  to  rise  more  than  one,  two,  three,  or 
four  degrees  of  Fahrenheit's  scale  at  the  utmost. 
As  in  these  experiments  the  object  especially 
proposed  was  to  determine    the  degree  of 
external  temperature  which  the  body  could 
bear,  all  the  attention  which  would  have  been 
desirable  was  not  given  to  determine  the  tem- 
perature of  the   body   before,  during,  and 
after  the  experiments.    This  is  an  omission 
which  is  common  to  the  experiments  of  For- 
dyce and  Dobson.    The  highest  temperature  of 
the  body  noted  by  Dr.  Dobson  is  102°  F.,  but 
he  does  not  mention  the  heat  before  the  experi- 
ment, nor  does  he  notice  the  rate  of  cooling 
subsequent  to  its  termination.     The  highest 
temperatures  of  the  human  body  exposed  to 
excessive  heats  ever  observed,  were  remarked 
by  Messrs.  Delaroche  and  Berger  in  their  own 
persons.    The  temperature  of  M.  Delaroche 
being  56°  56  c.  (98°  F.)  increased  5°  of  the 
centigrade  scale,  by  remaining  exposed  in  a 
chamber  the  temperature  of  which  was  80°  c. 
(176°  F.).   M.  Berger,  whose  temperature  was 
the  same  as  that  of  M.   Delaroche,  gained 
4°c.  by  remaining  for  sixteen  minutes  in  the 
hot  chamber  at  87°  c.  (188°,  5  F.).  These 
experiments  are  liable  to  this  objection, — that 
the  temperature  was  taken  in  the  mouth  in  an 
atmosphere  of  much  higher  temperature,  which 
might  have  some  influence  in  raising  the  ther- 
mometer.    To  arrive  at  conclusions  against 
which  no  kind  of  objection  could  be  raised, 
Messrs.  Delaroche  and  Berger  exposed  them- 
selves in  succession  in  a  box,  out  of  which  they 
could  pass  their  head  ;  the  hot  air  or  vapour  of 


ANIMAL  HEAT. 


661 


the  interior  being  prevented  from  escaping  by 
means  of  a  circular  pad  of  soft  napkins  placed 
between  the  edge  of  the  outlet  and  the  neck. 
The  temperature  of  the  mouth,  in  this  way,  if  it 
was  increased,  must  be  increased  in  consequence 
of  a  rise  of  temperature  in  the  parts  of  the  body 
included  in  the  bath.  After  a  stay  of  seventeen 
minutes  in  the  bath,  heated  from  37°,  5  to 
48°,  75  c.  (99°  to  120°  F.),  the  temperature  of 
M.  Delaroche's  mouth  rose  3°,  12  c.  Under 
similar  circumstances,  the  temperature  of  the 
bath  being  from  40°  to  41°,  25  c.  (104°  to 
106°  F.),  the  temperature  of  M.  Berger's  mouth 
increased  1°,  7  c.  in  the  course  of  fifteen 
minutes. 

It  is  pretty  obvious  that  experiments  upon 
the  human  subject  cannot  be  pushed  far  enough 
to  ascertain  the  highest  amount  of  temperature 
that  can  be  acquired  under  the  influence  of 
exposure  to  air  of  excessively  high  tempera- 
ture. To  judge  of  this  analogically,  recourse 
must  be  had  to  warm-blooded  animals  of  the 
two  classes,  Mammalia  and  Birds.  Messrs. 
Delaroche  and  Berger  consequently  exposed 
different  species  of  Mammalia  and  Birds  to  dry 
hot  air  of  different  temperatures,  from  50°  to 
03°,  75  c.  (122°  to  201°  P.),  leaving  them  im- 
mersed till  they  died.  The  whole  of  the  ani- 
mals that  were  made  subjects  of  experiment, 
in  spite  of  diversity  of  class  and  species,  and 
of  the  varieties  of  temperature  to  which  they 
were  exposed,  had  gained  an  increase  of  tem- 
perature nearly  equal  at  the  moment  of  their 
death.  The  limits  of  the  variations  being  be- 
tween the  terms  6°,  25  and  7°,  18  c,  the  amount 
of  difference  did  not  exceed  0°,  93  c.  which  is  a 
very  triflingquantity.  It  may  therefore  be  inferred 
that  man  and  the  warm-blooded  animals  cannot, 
under  the  influence  of  exposure  to  dry  air  of 
excessively  high  temperature,  have  the  heat  of 
their  body  raised  during  life  to  a  greater  extent 
than  from  7°  to  8°  c.  The  temperature  of  the 
body  being  increased  to  this  extent  becomes 
fatal.  It  is  in  fact  only  attained  at  the  moment 
of  dissolution  ;  perhaps  death  has  virtually 
taken  place  before  it  is  attained. 

We  have  seen  that  Franklin  observed  the 
temperature  of  his  body  to  be  lower  than  that 
of  the  air  on  a  very  hot  day.  Such  a  circum- 
stance is  rare  in  what  may  be  called  natural  con- 
ditions as  regards  man  and  the  warm-blooded 
animals  ;  inasmuch  as"  it  rarely  happens  that 
the  temperature  of  the  air  surpasses  that  of 
their  bodies  generally.  The  case  is  different, 
however,  as  regards  the  cold-blooded  tribes. 
It  is  not  at  all  necessary  that  the  temperature 
of  the  air  be  very  high  to  afford  opportunities 
of  observing  the  phenomenon  in  question 
among  cold-blooded  animals.  This  was  ob- 
served for  the  first  time  by  Sir  Charles  Blagden 
in  a  frog,  which  on  a  summer's  day,  when  the 
heat  was  by  no  means  excessive,  he  observed  to 
be  lower  in  temperature  than  the  surrounding 
air.  A  fact  of  this  kind  could  not  remain 
isolated  and  unconnected  with  others.  Accord- 
ingly we  observe  among  the  experiments  of 
Dr.  Davy  such  facts  as  the  following: — The 
temperature  of  the  atmosphere  being  32°  c. 
(90°  F.),  that  of  a  tortoise  was  only  29°,  4 


(85°  F.).  The  air  marking  26°,  7  (80°  F.), 
a  frog  indicated  25°  (77°  F.).  The  air  being  at 
28°,  3  (83°  F.),  the  blatta  orientalis  was  at 
23°,  9  (75°  F.).  The  air  at  26°,  19  c, 
(79°,  5  F.),  a  scorpion  was  at  25°,  3  (78°  F.). 
It  is  therefore  apparent  that  the  phenomenon  is 
general  among  animals  with  cold  blood  ;  that 
during  the  highest  heats  of  summer,  the  tem- 
perature still  falling  short  of  excessive,  the  heat 
of  their  bodies  is  below  that  of  the  air.  There 
is  thus  a  limit  of  summer  temperature  which 
separates  two  orders  of  phenomena  relative 
to  the  temperature  of  cold-blooded  animals. 
Starting  from  a  mean  temperature  of  the  air, 
that  of  cold-blooded  animals,  the  vertebrate 
as  well  as  the  invertebrate  tribes,  is  superior  to 
this  mean,  only  varying  in  this  respect  within 
the  narrow  limits  of  from  a  few  fractional  parts 
of  a  degree  to  about  four  degrees  centigrade, 
until  the  air  attains  the  summer  heat.  Towards 
this  limit  the  differences  decrease,  and  the 
term  25°  or  26°  c.  (77°  to  79°  F.) attained,  they 
become  nil.  The  inverse  phenomenon  is  also 
observed  :  the  temperature  of  the  greater  num- 
ber is  inferior  to  that  of  the  air,  and  the  dif- 
ferences go  on  increasing  with  the  rise  in 
temperature  of  the  external  air. 

These  phenomena  are  of  great  interest  in 
themselves,  but  of  still  greater  from  the  light 
they  cast  on  questions  of  a  similar  kind  relative 
to  man  and  the  warm-blooded  tribes  of  crea- 
tion. The  slight  evolution  of  heat  by  the  cold- 
blooded animals  rendering  their  condition  more 
simple,  allows  us  to  appreciate  distinctly  the 
influence  of  external  causes. 

We  now  proceed  to  tieatof  a  third  condition 
influencing  temperature,  namely, 

Evaporation. — The  fluids  so  far  surpass  the 
solids  in  the  bodies  of  animals  that  they  cer- 
tainly constitute  the  larger  portion  of  their 
masses ;  and,  further,  the  exterior  surface  of 
animal  bodies  generally  is  extremely  porous. 
Animals  are  consequently  subjected  to  the 
ordinary  physical  laws  of  evaporation.  It  is 
very  long  since,  in  addition  to  the  sweat  Di- 
visible perspiration,  the  existence  of  an  invisible 
perspiration  has  been  recognized.  The  latter  is 
owing  in  great  part  to  the  effects  of  evaporation. 
Now  evaporation  cannot  take  place  without  the 
occurrence  of  cooling  or  loss  of  temperature 
in  the  ratio  of  the  quantity  of  vapour  formed. 
Without  keeping  this  cause  of  refrigeration  in 
view,  we  should  fall  into  serious  mistakes  in 
estimating  the  heat  of  animals.  If,  for  ex- 
ample, we  would  compare  the  heat  of  two 
animals,  which,  unwittingly  to  the  observer, 
should  be  under  different  conditions  of  eva- 
poration, we  should  deceive  ourselves  greatly 
in  regard  to  their  respective  temperatures. 

It  is  even  so  with  reference  to  another  fact 
bearing  upon  temperature,  which  is  often  forced 
on  the  attention,  and  which  has  almost  always 
led  inquirers  into  error.  There  are  many  ani- 
mals among  the  inferior  classes  of  the  Inverte- 
brata,  which  tried  by  the  thermometer  exhibit 
no  difference  in  temperature  from  that  of  the 
surrounding  air.  These  creatures  do  not  con- 
sequently, appear  to  have  any  faculty  of  pro- 
ducing heat.   But  in  the  mere  fact  of  their  main- 


662 


ANIMAL  HEAT. 


taming  the  temperature  of  the  air  about  them, 
an  inherent  capacity  to  produce  heat  is  apparent. 
Did  they  evolve  no  caloric,  they  would  fall 
below  the  temperature  of  the  air,  in  conse- 
quence of  the  evaporation  which  goes  on  from 
the  surface  of  their  bodies.  They  must  of 
necessity  produce  as  much  as  is  necessary  to 
repair  the  loss  which  takes  place  from  this 
cause. 

What  we  have  said  of  animals  is  equally 
applicable  to  vegetables.  To  explain  the  pro- 
gression of  the  temperature  of  cold-blooded 
animals,  which  we  have  exposed  above,  regard 
must  be  had  to  the  relation  which  connects  the 
quantity  of  vapour  formed  with  the  degree  of 
external  temperature.  Within  moderate  limits, 
which  may  be  styled  temperate,  the  vapour 
formed  will  be  nearly  as  the  degrees  of  tem- 
perature of  the  air.  But  under  higher  tempera- 
tures, evaporation  will  go  on  in  a  greater  ratio 
than  that  of  the  external  temperature.  Thus 
when  the  air  is  cool  or  moderately  warm,  eva- 
poration is  trifling,  and  among  the  superior 
classes  of  cold-blooded  animals  heat  enough  is 
produced  to  maintain  their  temperature  above 
that  of  the  air.  But  when  the  air  becomes 
warmer,  as  in  the  height  of  summer,  evapora- 
tion and  the  cold  which  results  from  it  increase 
in  a  far  greater  ratio  than  the  temperature  of 
the  body,  so  that  the  body  remains  at  a  tem- 
perature inferior  to  that  of  the  air,  and  this 
by  so  much  the  more  as  the  external  tempera- 
ture rises  higher.  Twenty-five  degrees  is  the 
limit  at  which  this  change  commences  in  regard 
to  cold-blooded  animals.  But  it  is  obvious 
that  a  higher  degree  must  be  necessary  to  ob- 
serve such  phenomena  in  man  and  the  warm- 
blooded tribes,  inasmuch  as  the  heat  from 
without  is  for  a  long  time  added  to  that  pro- 
duced internally,  and  which  among  the  warm- 
blooded tribes  is  so  much  greater  in  amount 
than  it  is  among  the  cold-blooded. 

Relations  of  the  bulk  of  the  body  with 
animal  heal. — If  the  temperature  of  the  larger 
animals  be  compared  with  that  of  the  smaller, 
it  will  be  found  that  the  former  do  not  mark 
so  high  a  degree  as  the  latter.  In  the  elephant 
and  horse,  for  instance,  no  higher  a  temperature 
than  37°,  5  c.  (100°  F.)  has  been  observed, 
whilst  in  the  rat  and  squirrel  temperatures  of 
38°,  8,  and  of  39°,  4  (102°  and  103°  F.)  have 
been  noted.  To  prove  that  the  difference  is 
less  owing  to  the  order  or  species  than  to  the 
simple  size,  we  shall  contrast  several  animals 
belonging  to  the  same  order,  selecting  the 
ruminants.  The  temperature  of  the  air  being 
the  same,  namely,  26°  c.  (79°  F.),  the  tem- 
perature of  the  ox  was  found  to  be  38°,  9 
(102°  F.),  whilst  that  of  a  castrated  he-goat 
was  39°  5  (103°  F.),  and  that  of  the  she-goat 
and  sheep  40°  (104°  F.)  * 

It  is  evident  that  smallness  of  size  must  in 
itself  be  one  of  the  conditions  unfavourable  to 
height  of  temperature  among  animals,  when 
this  is  merely  viewed  in  relation  with  the  am- 
bient medium.  As  the  external  temperature  is 
almost  always  lower  than  that  of  the  bodies  of 

*  Vide  Observ.  of  Dr.  Davy. 


animals,  the  ambient  medium  tends  to  lower 
their  temperature  ;  and  small  bodies  having  a 
more  extensive  surface  in  reference  to  their  mass 
than  large  bodies,  small  animals  must  have  a 
greater  tendency  to  lose  heat  than  larger  animals. 
But,  on  the  other  hand,  the  circulation  and 
respiratory  motions  generally  increase  in  rapidity 
in  proportion  to  the  smallness  of  size ;  and  we 
have  seen  that  acceleration  of  these  motions 
had  an  influence  in  keeping  up  the  temperature. 
With  a  small  size  of  the  body,  consequently, 
we  find  associated  a  higher  activity  of  function 
which  tends  to  compensate  the  disadvantage 
resulting  from  inferior  size  in  reference  to  tem- 
perature. In  fact  it  constantly  happens  that 
this  higher  activity  more  than  compensates  the 
cooling  disposition  from  inferiority  of  size,  and 
causes  the  balance  to  incline  towards  the  side  of 
higher  temperature.  It  must  be  apparent, 
however,  that  there  is  no  occasion  for  such  a 
preponderance  always  existing  in  the  case  of 
small  animals.  And  then  we  know  that  the 
motions  of  circulation  and  of  respiration  cannot 
be  greatly  accelerated  without  causing  incon- 
venience and  even  danger  to  health  and  life. 
It  follows  that  the  external  temperature  being 
liable  to  fall  disproportionately  low,  small  ani- 
mals have  not,  under  like  disadvantageous  cir- 
cumstances, the  same  power  as  larger  animals 
of  supporting  their  temperature.  The  relations 
of  size  naturally  lead  us  to  consider  those  that 
depend  on  age. 

Relations  of  age  with  animal  heat. — The 
size  of  the  body  changes  with  the  age.  The 
same  relations  between  bulk  of  body  and  de- 
velopment of  heat  ought  therefore  to  be  ex- 
hibited in  youth  as  compared  with  adult  age. 
In  early  life  the  greater  rapidity  of  the  motions 
of  circulation  and  respiration,  all  things  else 
being  equal,  ought  to  increase  the  heat.  At 
the  same  time  the  constitution  differs  in  other 
respects,  and  if  these  were  unfavourable  to  the 
evolution  of  heat,  it  would  be  impossible  to 
foresee  the  result  of  these  two  opposite  ten- 
dencies. Nevertheless  it  is  probable,  from 
what  we  have  seen  to  happen  in  warm-blooded 
animals  of  different  sizes,  that  there  might 
occur  a  period  in  early  life  when  the  heat  would 
be  higher  than  in  adult  age.  A  confirmation 
of  this  inference  may  be  found  in  comparing  the 
different  observations  of  Dr.  Davy,  who  has 
given  a  table  of  the  temperatures  of  fifteen  chil- 
dren from  four  to  fourteen  years,  the  mean  age 
of  the  whole  being  nine  years  and  nine  months. 
The  mean  temperature  of  the  bodies  of  these 
children  was  38°,  31  (101°  F.).  But  the  mean 
temperature  of  twenty-one  adults  was  no  higher 
than  37°,82  (100°  F.):  a  difference  that  seems 
the  more  worthy  of  being  confided  in  from  the 
temperature  of  the  air  having,  at  the  time  of 
the  observations,  been  more  favourable  for  the 
adults  than  for  the  children,  this  having,  in  re- 
ference to  the  former,  been  26°  and  26°,  7 
(79°  and  80°  F.),  whilst  when  the  latter  were 
made  the  subjects  of  investigation,  it  was  but 
24°  and  26°  (75°,  5  and  79°  F.). 

It  seems  impossible,  therefore,  to  doubt  from 
what  precedes,  that  size  is  not  an  element 
which  has  much  influence  in  the  particular 


ANIMAL  HEAT. 


663 


direction  we  are  considering.  We  have  seen 
that  with  a  decrease  in  the  size  of  adult  Mam- 
malia the  circulatory  and  respiratory  motions 
were  progressively  accelerated,  and  that  by  this 
means  the  disadvantages  as  regards  cooling  in 
consequence  of  a  smaller  relative  size  of  the 
body,  are  in  some  measure  compensated,  some- 
times, indeed,  we  have  seen  the  balance  in- 
clined the  other  way,  and  the  greater  rapidity 
of  the  motions  more  than  compensate  for  the 
diminished  size  of  the  body.  Great  rapidity 
of  the  respiratory  and  circulatory  motions  may 
co-exist  with  other  organic  conditions  having 
an  opposite  tendency  as  regards  temperature  ; 
and,  according  to  the  relations  of  these,  and 
as  the  one  or  the  other  predominates,  we  may 
have  two  different  states  of  temperature  in 
early  life.  This  proposition  is  even  made  ap- 
parent when  we  compare  the  constitution  in 
early  youth  and  in  adult  age.  In  early  life  the 
celerity  of  the  motions  has  led  to  the  belief 
that  all  the  functions  of  nutrition  were  pecu- 
liarly active.  But  strength  or  energy  is  not 
always  an  accompaniment  of  simple  celerity ; 
on  the  contrary  rapidity  is  generally  indicative 
of  absence  of  power.  It  is  quite  true  that  in 
early  life  not  only  are  circulation  and  respira- 
tion, but  digestion,  assimilation,  and  growth 
likewise,  much  more  rapid  than  in  the  adult 
state.  But  does  it  follow  from  this  thut  the 
materials  of  the  blood  are  elaborated  in  the 
same  degree  of  perfection,  or  that  the  products 
of  the  action  and  contact  of  this  fluid,  the 
vaiious  tissues,  &c.  of  the  body,  are  all  as  com- 
pletely formed  ?  Everything  conduces  to  make 
us  believe  that  the  reverse  is  the  case.  If  on 
the  one  hand  rapidity  of  movement  be  a  cha- 
racter of  early  life,  weakness  is  a  feature  still 
more  manifest.  If  the  nervous  system  there- 
fore, although  acting  rapidly,  is  less  energetic, 
in  the  same  proportion  there  may  be  an  age  at 
which  the  influence  of  this  weakness  on  the 
production  of  heat  may  be  manifest.  And,  as 
the  weakness  is  greater  as  the  being  is  younger, 
it  is  in  the  very  earliest  periods  of  independent 
existence  that  this  relation  must  be  inves- 
tigated. Now  such  a  relationship  does  aclually 
exist,  although  an  opinion  to  the  contrary  had 
always  been  entertained  until  direct  experi- 
ments settled  the  question  definitively.  These 
experiments  were  performed  by  the  writer,  and 
a  summary  of  them  is  here  given.  If  the 
temperature  of  new-born  puppies  lying  beside 
their  mother  be  taken,  it  will  be  found  from 
one  to  three  degrees  inferior  to  that  of  the 
parent.  The  same  thing  obtains  in  regard  to 
the  young  of  the  rat,  the  rabbit,  the  guinea-pig, 
&c.  and  is  probably  universal  among  the  Mam- 
malia. Among  Birds  the  same  circumstance 
presents  itself  in  a  still  more  marked  degree. 
If  they  be  taken  out  of  the  nest  in  the  first 
week  or  even  fortnight  of  their  existence,  the 
difference  of  temperature  extends  to  from  2° 
to  5°  c.  between  the  young  and  the  parents. 
The  fact  has  been  ascertained  in  regard  to  the 
sparrow,  the  swallow,  the  martin,  the  sparrow- 
hawk,  the  magpie,  the  thrush,  the  starling, 
fcc.  &c,  and  is  probably,  as  among  Mammalia, 
universal.    Whence  we  may  conclude  that  the 


phenomenon  is  general  as  regards  warm-blooded 
animals.  We  might  have  taken  it  for  granted 
that  man  was  comprised  within  the  category, 
but  it  is  just  as  well  to  have  the  assurance  that 
he  forms  no  exception  to  the  law,  that  he  has 
no  peculiar  privilege  in  this  respect.  To  have 
a  precise  term  of  comparison,  the  temperature 
of  twenty  adults  was  taken  at  the  same  time, 
the  thermometer  being  applied  in  the  axilla. 
The  temperature  of  these  twenty  persons  varied 
between  35°,  5  and  37°  c.  (96°  and  99°  F.) ; 
the  mean  term  was  therefore  36°,  12  (97°  F.). 
The  temperature  of  ten  infants  varying  from  a 
few  hours  to  two  days  in  age,  ascertained  in 
the  same  manner, varied  between  34°  and  35°  5 
c.  (93°,  5  and  96°  F.).  The  mean  was  there- 
fore 34°,  75  c.  (about  94°,  5  F.).  There  was 
consequently  a  difference  of  nearly  two  degrees 
between  the  temperature  of  the  adult  and  of 
the  newly  born  babes.  Man  is  therefore  proved 
to  be  subjected  to  the  same  law  here  as  ani- 
mals having  warm  blood  in  general,  the  young 
of  which,  so  far  as  they  have  been  examined, 
and  we  may  presume  universally,  are  inferior 
in  temperature  to  their  parents. 

There  are,  therefore,  two  periods  in  youth  at 
which  the  bodily  temperature  differs  from  that 
of  the  adult  age.  These  may  be  distinguished 
as  the  first  and  second  periods  of  infancy  or 
youth.  The  first  extends  from  birth  to  an  in- 
definite period,  but  which  is  nearer  or  more 
remote  from  the  period  of  birth  in  different 
cases.  The  second  is  included  between  the 
fourth  and  the  fourteenth  year ;  the  limits  can- 
not be  more  accurately  determined.  In  the 
first  the  temperature  is  lower  than  in  adult  age, 
in  the  second  it  is  higher  The  differences  of 
temperature  in  the  first  age  of  infancy,  and  the 
adult  age,  although  very  sensible  and  impor- 
tant as  regards  the  economy,  are  indices  of  a 
difference  incomparably  greater  than  their 
numerical  indication  might  be  taken  to  imply. 
In  fact,  if  the  manner  of  observing  be  altered, 
results  of  so  extraordinary  a  character  are  come 
to  as  to  surpass  all  expectation.  To  deve- 
lope  these  the  temperature  of  the  newly  born 
being  must  not  be  taken  only  when  it  is  in 
contact  with  its  mother.  If,  after  having  as- 
certained the  temperature  of  a  puppy  in  this 
position,  it  be  removed  from  the  mother  and 
kept  isolated,  the  temperature  will  be  found  to 
fall  rapidly;  and  this  phenomenon  takes  place 
not  only  when  the  air  is  cold,  but  when  it  is 
mild.  The  phenomenon  does  not  commence 
after  a  term ;  it  is  apparent  from  the  moment 
the  separation  takes  place,  and  is  very  sensi- 
ble after  the  lapse  of  a  few  minutes.  The  fol- 
lowing is  the  rate  of  cooling  of  a  puppy  twenty- 
four  hours  old,  the  external  temperature  being 
13°  c.  (about  55°,  5  F.),  taken  at  intervals  of 
ten  minutes;  the  series  of  course  represents 
the  successive  losses  of  temperature  in  the 
course  of  the  small  intervals  of  time  indicated  : 
— temperature  in  commencing  the  observations 
36°,  87  c;  the  declensions  in  temperature  at 
intervals  of  ten  minutes  successively,  0°,  63 
1°,  12,  1°,38,  1°,25,  1°,29,  0°,  87,  1°,63, 
0°,  25,  1°,  0;  in  thirty-five  minutes  the  tem- 
perature declined  farther  1°,  25;  in  thirty-five 


664 


ANIMAL  HE  AT. 


minutes  more  it  fell  3°,  12;  in  thirty  minutes 
more  2°,  50;  in  twenty-five  minutes  more 
1°,  25;  in  thirty  minutes  morel0,  25;  so  that 
in  the  course  of  four  hours  in  all  the  tempe- 
rature declined  by  the  amount  of  18°,  12' of 
the  centigrade  scale  (about  33°  F.)!  Not  only 
had  the  temperature  of  the  animal  sunk  by  so 
large  a  quantity  in  so  short  a  period  of  time, 
the  external  temperature  being  pleasant,  but  it 
actually  could  maintain  its  temperature  at  no 
higher  a  grade  than  6°,  75  c.  (44°,  5,  F.)  above 
that  of  the  atmosphere.  Experiments  of  the  same 
kind  performed  on  three  other  puppies  of  the 
same  litter  presented  results  in  all  respects 
analogous.  The  cooling  may  even  go  much 
further  by  protracting  the  period  during  which 
the  young  animals  are  kept  apart  from  their 
parent.  For  instance,  four  puppies,  twenty- 
four  hours  old  and  of  much  smaller  size  than 
the  subjects  of  the  former  experiments,  after 
having  sunk  16°  c.  in  four  hours  and  thirty 
minutes,  lost  six  degrees  more  of  temperature 
in  the  succeeding  eight  hours  and  thirty  mi- 
nutes, the  air  remaining  all  the  while  at  13°  c. 
(55°,  5  F.).  They  consequently  lost  twenty- 
two  degrees  centigrade  in  thirteen  hours;  and, 
what  is  very  remarkable,  their  final  temperature 
was  but  one  degree  above  that  of  the  surround- 
ing air.  Kittens  and  rabbits  of  the  same  age 
exhibited  similar  phenomena,  if  possible  in  a 
more  striking  degree.  Some  kittens  were  ob- 
served to  cool  twenty  degrees  centigrade  within 
the  short  interval  of  three  hours  and  a  half, 
and  some  young  rabbits  suffered  the  same  de- 
pression of  temperature  in  two  hours  and  ten 
minutes,  the  air  being  at  the  time  at  14°  c. 
(57°,  5  F.).  These  phenomena  are  unques- 
tionably among  the  most  remarkable  we  wit- 
ness in  warm-blooded  animals.  For  here  we 
have  species  of  different  genera  of  the  Carni- 
vora  and  Rodentia,  which  at  two  periods  of 
their  existence  present  the  extremes  in  the  pro- 
duction of  heat.  They  may  be  said  to  be, 
to  all  intents  and  purposes,  cold-blooded  ani- 
mals, with  reference  to  temperature,  during 
the  earliest  period  of  life;  they  are  only  truly 
warm  blooded  animals  in  a  later  stage  of  their 
existence.  The  same  phenomena  undoubtedly 
present  themselves  in  many  other  species  ;  but 
it  would  not  be  reasonable  to  suppose  that  they 
were  exhibited  by  all. 

The  phenomena  being  connected  with  the 
state  of  constitution,  it  may  be  expected  to 
vary  in  diffeient  genera  and  families;  and  this, 
in  fact,  is  what  actually  happens.  A  young 
guinea-pia,  for  instance,  having  a  temperature 
of  38°  c.  (101°,  5  F.),  will  maintain  this  tem- 
perature when  the  atmosphere  is  mild,  although 
separated  from  its  mother.  It  is  the  same  with 
the  goat.  These  instances  are  enough  to  give 
us  a  key  to  the  external  characters  in  relation 
with  the  different  capacities  to  produce  heat 
inherent  in  the  young  Mammalia.  In  the  first 
place  we  observe  a  manifest  relation  with  the 
state  of  energy  of  the  nervous  system  :  on  the 
one  hand  we  have  the  puppy,  the  kitten,  the 
rabbit,  which  are  born  extremely  weak  ;  on  the 
other  we  have  those  animals  that  come  into  the 
world  in  a  condition  to  walk,  to  eat,  and,  as  it 


were,  furnished  forth  to  a  certain  extent  with 
the  means  of  providing  for  their  wants.  The 
question,  however,  is  to  discover  some  zoolo- 
gical character  in  relation  with  these  differ- 
ences. If  this  were  to  be  derived  from  the 
state  of  the  organs  of  locomotion,  of  the  faculty 
of  walking,  we  should  sometimes  be  led  into 
error ;  for  man,  at  the  period  of  his  birth  and 
long  afterwards,  is  not  in  a  condition  to  hold 
himself  erect,  and  yet  his  temperature  is  main- 
tained to  within  one  or  two  degrees  of  that  of 
his  mother,  if  the  external  temperature  be  but 
mild.  There  is,  however,  one  character  that 
appears  general ;  this  is  the  state  of.  the  eyes. 
Those  species  of  Mammalia  which  in  the  earlier 
period  of  their  existence  do  not  maintain  their 
temperature,  that  of  the  external  atmosphere 
being  mild  or  warm,  but  cool  down  to  the 
stundard  of  the  cold-blooded  animals,  are  born 
with  their  eyes  closed ;  whilst  those  which  main- 
tain their  temperature,  that  of  the  external 
atmosphere  being  mild,  are  born  with  their  ei/es 
open  ;  and  this,  whether  they  can  walk  about 
like  the  guinea-pig,  the  kid,  &c,  or  cannot  do 
so,  as  is  the  case  with  the  human  infant  in  par- 
ticular. 

This  general  view  of  the  state  of  energy  of  the 
nervous  system  in  relation  with  the  production 
of  heat  in  early  life,  comes  in  aid,  in  a  very 
remarkable  manner,  of  the  general  principles 
which  have  been  already  deduced  in  regard  to 
the  calorific  power.  In  going  more  deeply 
into  the  subject,  the  confirmation  becomes  more 
manifest  and  more  complete.  The  state  of  the 
eyes  affords  a  mere  external  and  zoological  in- 
dication. It  is  but  an  indication  of  other  deep 
modifications  of  the  economy,  which  it  is 
essential  to  determine  more  closely.  Now  in 
examining  the  state  of  the  organs  generally  of 
puppies  at  the  period  of  their  birth,  we  observe 
a  remarkable  disposition  of  the  sanguiferous 
system.  The  ductus  arteriosus  continues  per- 
vious and  of  large  size.  The  consequence  of 
this  structure  is  that  a  free  communication  is 
established  between  the  arterial  and  venous 
blood,  by  which  they  are  mingled  in  large  pro- 
portion one  with  another.  And  here  we  have 
precisely  the  physiological  character  derived 
from  the  nature  or  quality  of  the  blood  which 
distinguishes  the  cold-blooded  from  the  warm- 
blooded Vertebiata  (in  the  adult  age  under- 
stood). This  character  is  exactly  the  same  in 
the  other  species  of  Mammalia  which  we  have 
mentioned  as  losing  temperature  and  attaining 
the  standard  of  the  cold-blooded  tribes.  On 
the  other  hand,  in  the  guinea-pig,  to  take  an 
individual  instance,  which  from  the  first  day  of 
its  extra-uterine  existence  maintains  its  tempera- 
ture nearly  on  a  level  with  that  of  its  parent 
when  the  air  is  temperate,  the  ductus  arteriosus 
is  closed  immediately  after  birth.  The  arterial 
remaining  distinct  from  the  venous  blood,  this 
creature  is  therefore  born  with  the  organization 
characteristic  of  warm-blooded  animals,  and 
presents  phenomena  having  reference  to  calori- 
fication of  the  same  kind  as  adult  warm-blooded 
animals. 

This  relation  is  preserved  in  the  young 
Mammalia  in  every  modification  in  a  pecu- 


ANIMAL  HEAT. 


665 


liarly  interesting  manner.  The  young  Mam- 
malia which  are  born  with  the  eyes  closed,  at 
first  present  the  phenomena  of  refrigeration 
nearly  in  the  same  degree  during  the  two  or 
three  first  days  of  their  life  ;  though  they  after- 
wards exhibit  differences  of  great  extent  in  this 
respect.  Thus  a  young  rabbit  two  days  old  had 
cooled  down  to  14°  from  23°  c.  (to  58°  from 
74°  F.)  in  the  course  of  three  hours  fifty  minutes, 
theair  being  at  the  time  temperate ;  another  three 
days  old  took  seven  hours  twenty-five  minutes 
to  cool  through  a  range  of  18°  c,  when  the 
process  of  refrigeration  ceased.  A  third,  of  the 
age  of  five  days  only,  lost  5°  c.  in  temperature 
in  the  course  of  one  hour  fifty-five  minutes, 
and  maintained  itself  afterwards  at  this  tem- 
perature. During  the  following  days,  smaller 
and  smaller  depressions  of  temperature  were 
observed,  till  the  eleventh  day  after  birth,  when 
the  power  of  sustaining  the  temperature  a  little 
below  that  of  the  adult  female  parent  seemed  to 
be  acquired  permanently.  When  the  modifi- 
cations of  internal  structure  are  examined 
during  this  interval  of  time,  we  find  that  the 
ductus  arteriosus  has  been  contracting  in  the 
same  proportion  as  the  faculty  of  maintaining 
the  temperature  has  been  increasing,  and  that  it 
is  entirely  closed  at  the  epoch  when  the  tem- 
perature becomes  stationary,  the  external  tem- 
perature being  understood  all  the  while  as 
mild  or  pleasant.  At  the  same  period  pre- 
cisely too,  the  eyes  are  unsealed,  a  circum- 
stance which  confirms  the  exactness  of  the 
character  derived  from  the  state  of  this  latter 
organ,  as  distinctive  of  the  young  of  those 
Mammalia  which  are  born  as  it  were  cold- 
blooded animals,  from  those  that  come  into  the 
world  with  the  distinguishing  attribute  of  warm- 
blooded animals. 

Among  the  young  of  Birds  we  observe  as 
marked  differences  in  the  calorific  function  as 
we  have  just  acknowledged  among  Mammalia. 
Some  lose  heat  rapidly  when  separated  from  the 
mother;  others  maintain  their  temperature  to 
within  a  little  of  that  of  their  species.  Spar- 
rows, for  instance,  which  have  been  hatched  but 
a  short  while,  present  a  temperature  from  4°  to 
5°  c.  lower  than  that  of  their  parents  when  still 
contained  in  the  nest,  where  they  contribute  to 
each  other's  warmth.  But  taken  out  of  the 
nest  and  isolated,  although  the  temperature  be 
that  of  summer  they  begin  to  cool  with  extreme 
rapidity.  A  young  sparrow  a  few  days  old 
lost  as  many  as  12°  c.  in  the  short  space  of  one 
hour  seven  minutes,  the  air  at  the  time  marking 
22°  c.  (72°  F.).  The  same  thing  happens 
with  swallows,  sparrow-hawks,  &c.  But  the 
law  is  not  universal;  it  does  not  hold  in  re- 
ference to  all  the  genera.  There  are  several 
that  have  the  power  of  sustaining  their  tempera- 
ture in  spring  and  summer  at  a  degree  but 
little  below  that  of  their  parents.  Birds,  there- 
fore, form  two  groups  as  regards  the  production 
of  temperature,  just  as  the  Mammalia  do.  The 
first  cool  down  to  the  standard  of  cold-blooded 
animals;  the  second  preserve  their  warmth, 
when  the  air  is  mild  or  agreeable  as  it  is  in  the 
spring  and  summer.  But  the  zoological 
characters  that  distinguish  them  are  not  the 


same  as  among  mammiferous  animals.  All 
birds  are  hatched  or  born  with  their  eyes  open. 
But  there  are  other  characters  which  coincide 
with  the  difference  of  temperature;  and  this 
consists  in  the  absence  or  presence  of  feathers. 
The  covering  of  those  that  are  hatched  so  pro- 
vided, consists  in  a  kind  of  down,  very  close 
and  very  warm,  so  that  we  might  imagine 
the  differences  observed  in  the  liability  to  lose 
heat  or  in  the  capacity  to  engender  it,  belonged 
to  the  coat.  This  has  undoubtedly  some 
influence,  but  analogy  even  will  not  suffer 
us  to  ascribe  the  chief  effect  to  this  cause.  In 
the  Mammalia  which  are  born  with  their  eyes 
closed,  the  refrigeration  takes  place  to  the  same 
extent  whether  they  are  born  with  a  fur-coat, 
as  the  kitten,  the  puppy,  &c,  or  come  into 
the  world  naked  like  the  rabbit;  the  cooling  is 
only  more  rapid  in  the  latter  than  in  the  former. 
What  further  proves,  and  directly  proves,  that 
the  refrigeration  is  not  entirely  due  to  the  dif- 
ference in  the  external  condition  as  regards 
covering,  although  this  of  course  must  go  for 
something,  is  that  when  the  want  of  natural 
covering  is  artificially  supplied,  the  cooling  does 
not  go  on  the  less  certainly  on  this  account, 
and  to  the  same  ultimate  extent ;  it  only  takes 
place  somewhat  more  slowly.  The  counter- 
proof  is  attended  with  the  same  result.  An 
adult  sparrow  which  has  had  all  its  feathers 
clipped  off  does  not  at  first  suffer  loss  of  tem- 
perature to  the  extent  of  more  than  a  degree, 
and  by-and-by  recovers  even  this ;  whilst  a 
young  bird  of  the  same  species,  though  fur- 
nished with  some  feathers,  cools  rapidly  and  to 
a  great  extent,  as  we  have  already  seen.  Birds 
are  therefore  divided  into  two  groups  as  regards 
the  production  of  heat.  The  one  comprises 
those  that  are  hatched  with  the  skin  naked,  and 
which  cool  in  a  temperate  air  in  the  same 
manner  as  cold-blooded  animals ;  the  other 
embraces  those  that  are  produced  with  a 
downy  covering,  and  maintain  their  temperature 
at  a  considerable  elevation  in  the  ordinary  heat 
of  spring  and  sumtner. 

There  is  not  a  less  remarkable  contrast 
between  these  two  groups  of  birds  in  point 
of  calorific  power,  than  between  the  two 
groups  of  Mammalia  already  mentioned  ;  but 
the  zoological  or  external  characters  which  dis- 
tinguish them  in  the  present  instance  are  not  of 
the  same  kind.  The  state  of  the  eyes  does  not 
apply  here,  for  all  Birds  are  disclosed  with  their 
eyes  unsealed.  They  also  all  come  into  the 
world  with  the  ductus  arteriosus  closed  or  nearly 
so, — a  circumstance  which  might  have  been 
predicated,  or  inferred  from  analogy.  Yet  the 
young  of  Birds  in  the  power  of  producing  heat 
present  diversities  no  less  remarkable  than  are 
observed  among  the  young  of  the  Mammalia. 
The  separation  of  the  two  kinds  of  blood  con- 
sequently is  not  the  only  condition  which 
influences  the  production  of  heat;  but  all  that 
modifies  the  blood  on  the  one  hand,  and  the 
nervous  system  on  the  other,  as  we  have  had 
occasion  to  observe  in  a  previous  part  of  this 
paper.  Now  it  happens  that  we  have  an  op- 
portunity of  applying  this  principle  in  a  very 
particular  manner  in  the  instance  of  the  two 


666 


ANIMAL  HEAT. 


groups  of  Birds  that  engage  us,  and  that 
differ  so  essentially  in  their  powers  of  engender- 
ing caloric.  In  the  one  and  in  the  other  we 
observe  the  same  difference  in  the  state  of  the 
general  strength  which  we  have  observed  in  the 
corresponding  groups  of  the  Mammalia.  In 
the  one  which  cools  rapidly,  there  is  the  same 
state  of  weakness,  of  general  impotency  ;  in  the 
other  the  young  are  in  a  condition  to  walk,  and 
in  a  certain  sense  to  shift  for  themselves  as  soon 
as  they  have  escaped  from  the  shell'. 

We  perceive  then  in  the  first  place,  that  the 
nervous  system  is  much  less  energetic  in  the 
former  than  in  the  latter  group  ;  and  in  the 
second  place,  that  the  digestive  powers  are  in  an 
equal  degree  inferior  in  strength  ;  for  they  are 
not  only  unable  to  take  food  of  themselves  from 
muscular  incapacity,  but  also  from  the  lack  of 
the  requisite  instinct,  and,  farther,  from  their 
digestive  organs  not  being  in  a  condition  to 
elaborate  food  to  any  extent.  It  is  on  this  last 
account  that  the  parents  supply  their  young 
with  food  which  has  suffered  maceration  in 
their  own  crops,  or  has  even  in  their  stomachs 
undergone  a  kind  of  incipient  or  partial  solu- 
tion ;  or  otherwise  the  parents  have  the  instinct 
to  select  such  articles  as  are  easiest  of  digestion, 
and  best  fitted  for  the  weakly  state  of  the 
digestive  organs  of  their  progeny.  We  have 
already  observed  that  a  delect  in  the  powers  of 
digestion  implies  a  corresponding  imperfection 
in  the  blood.  Whence  we  must  conclude  by 
analogy  that  the  blood  in  the  birds  of  the  first 
group  is  inferior  in  quality  to  that  of  the  birds 
of  the  second  group.  We  consequently  still 
find  the  two  general  conditions  which  regulate 
the  production  of  heat  throughout  the  animal 
kingdom — the  state  of  the  blood,  the  slate  of 
the  nervous  system. 

The  same  principles  are  applicable  to  the 
first  period  in  the  existence  of  all  animals, 
without  distinction  of  groups,  as  compared  with 
adults.  On  the  one  hand  we  have  ascertained 
that  all  without  exception  have  a  temperature 
lower  than  that  of  their  parents  ;  on  the  other, 
nothing  can  be  more  manifest  than  their  inferi- 
ority with  reference  to  the  energy  of  the  nervous 
system.  And  more  attentive  and  extensive  ex- 
amination shows  that  this  extends  in  like  man- 
ner to  the  digestive  functions,  and  consequently 
to  those  of  nutrition  generally. 

Let  us  first  turn  our  eyes  to  the  Mammalia. 
All  of  these  are  evidently  inferior  in  this  respect 
to  the  adult.  This  is  proclaimed  in  the  distin- 
guishing character  of  the  class :  the  females  are 
provided  with  glands  for  the  purpose  of  prepa- 
ring a  food  appropriate  to  the  state  of  weakness 
of  their  young.  The  state  of  the  mouth  of  the 
young  is  a  sufficient  index  of  the  defective 
power  of  the  digestive  organs ;  the  jaws  are 
either  wholly  or  partially  without  teefh.  The 
softness,  delicacy,  paleness  of  colour,  and  insi- 
pidity of  the  tissues  of  young  Mammalia,  com- 
plete the  evidence  of  the  imperfect  elaboration 
of  the  nutrient  juices.  If,  therefore,  the  first 
and  last  products  of  the  nutritive  functions  are 
in  an  inferior  condition,  can  we  suppose  that 
the  intermediate  product,  the  blood,  will  not 
participate  in  this  inferiority?  We  have  already 


shown  in  what  this  consists  among  the  Birds  of 
the  first  group.  With  regard  to  the  second,  the 
general  considerations  relative  to  the  difference 
of  the  tissues  is  equally  applicable  to  them,  and 
these  considerations  possess  a  high  value. 
When  very  young  warm-blooded  animals,  with- 
out any  exception,  are  compared  in  this  respect 
to  the  cold-blooded  Vertebrata,  we  perceive  a 
great  analogy  in  their  component  tissues,  which 
are  softer  and  less  savoury  than  among  the 
adults  of  warm-blooded  animals.  It  is  thus 
that  we  can  account  for  a  striking  anomaly  in 
the  nervous  system  of  young  warm-blooded 
animals,  especially  Mammalia.  Their  nervous 
system,  particularly  the  encephalon,  bears  a 
higher  proportionate  ratio  to  the  whole  body 
than  it  does  in  the  adult;  but  the  softness  and 
the  other  characters  of  the  tissue  of  this  organ 
in  early  life  cause  it  to  approximate  in  a  re- 
markable manner  in  appearance  and  character 
to  the  same  tissue  in  the  cold-blooded  Verte- 
brata: If,  therefore,  the  relative  volume  predo- 
minate in  early  life,  one  of  the  conditions 
favourable  to  calorification,  the  inferiority  in 
respect  of  tissue  counterbalances  this  advan- 
tage, and  is  only  compatible  with  very  inferior 
manifestations  of  energy. 

It  is  obvious  then  that  there  is  a  universally 
pervading  analogy  between  warm-blooded  ani- 
mals in  the  first  stages  of  their  existence  and 
adult  cold-blooded  Vertebrata,  and  that  the  pa- 
rallel holds  good,  not  merely  with  reference  to 
their  inferior  power  of  producing  heat,  but  also 
with  regard  to  the  functions  of  nutrition  gene- 
rally and  the  functions  of  the  nervous  system. 
There  is  one  point  upon  which  it  is  highly  ne- 
cessary to  insist,  inasmuch  as  it  is  of  the  greatest 
importance,  both  theoretically  and  practically ; 
it  is  this  :  that  the  analogy  in  the  direction  in- 
dicated is  by  so  much  the  more  remarkable  as 
the  warm-blooded  animal  is  born  with  charac- 
ters which  distinguish  it  more  strikingly  from 
those  it  possesses  when  arrived  at  maturity.  If 
it  is  born  with  the  eyes  closed,  or  without  fur 
or  feathers,  instead  of  with  the  eyes  open  and 
the  body  covered  with  a  fur  coat  or  a  thick 
down,  it  is  because  the  creature  comes  into  the 
world  less  perfectly  developed  in  every  respect, 
and  the  whole  economy  is  more  closely  allied 
to  that  of  inferior  orders.  This,  in  other  words, 
is  as  much  as  to  say  that  the  creature  is  born 
at  a  period  relatively  precocious,  or  in  a  more 
imperfect  condition.  Whence  it  may  be  in- 
ferred that  those  warm-blooded  animals  which 
are  born  at  a  period  short  of  the  ordinary  term 
of  utero-gestation  among  the  more  perfect  spe- 
cies, will  present  a  more  marked  analogy  with 
the  cold-blooded  tribes.  Man  himself  will 
form  no  exception  to  this  rule,  which  must  be 
quite  general.  The  verification  of  this  law  has 
been  completed  by  the  physiological  experiments 
of  the  writer.  A  child  born  at  the  seventh 
month,  perfectly  healthy,  and  which  had  come 
into  the  world  with  so  little  difficulty  that  the 
accoucheur  could  not  be  fetched  in  time  to  re- 
ceive it,  had  been  well  clothed  near  a  good  fire 
when  the  temperature  was  taken  at  the  axilla. 
This  was  found  no  higher  than  32°  c.  (under 
90°  F.).    Now  we  have  seen  that  the  mean  of 


ANIMAL  HEAT. 


667 


the  temperature  of  ten  children  born  at  the  full 
time  was  34°,7o  c.  (94°,5  F.) ;  the  tempera- 
ture in  no  case  descending  lower  than  34° 
(94°  F.)>  and  ranging  between  this  and  35°, 5  c. 
(96°  F.).  Let  it  be  Observed  that  at  the 
seventh  month  the  membrana  pupillaris  no 
longer  exists  ;  the  infant  has,  therefore,  at  this 
epoch  of  its  development,  the  essential  charac- 
ters of  warm-blooded  animals  capable  of  sup- 
porting a  high  temperature  when  that  of  the 
surrounding;  atmosphere  is  mild.  But  if  it 
were  entering  the  world  some  considerable  time 
before  the  disappearance  of  the  pupillary  mem- 
brane, it  would  be  in  a  condition  analogous  to 
the  Mammalia  which  are  born  with  their  eyes 
shut ;  it  would  no  longer  be  in  a  condition  to 
maintain  an  elevated  temperature,  and  without 
doubt  would  lose  heat  precisely  as  they  do 
without  precautions  to  the  contrary. 

When  we  take  a  general  view  of  the  first  and 
second  periods  in  the  early  life  of  warm-blooded 
animals,  we  find  that  they  are  under  the  influence 
of  two  general  conditions  relative  to  calorifica- 
tion ;  conditions  which,  acting  inversely,  tend 
to  compensate  each  other  mutually ;  on  the 
one  hand,  the  celerity  of  the  motions  ;  on  the 
other,  the  imperfection  of  the  nutrient  and  ner- 
vous functions.    The  celerity  of  the  motions  of 
circulation  and  respiration  diminishes,  whilst 
the  development  of  the  nutritive  and  nervous 
functions  increases  with  age.    These  two  con- 
ditions influencing  the  production  of  heat  are, 
therefore,  in  an  inverse  ratio  to  one  another. 
And  according  to  the  nature  of  these  relations 
will  the  temperature  vary.    Were  the  opposite 
effects  equal,  there  would  be  exact  compensa- 
tion in  the  whole  phases  of  the  evolution,  from 
the  moment  of  birth  to  that  of  perfect  adole- 
scence, and  the  temperature  of  the  body  would 
be  the  same  at  every  period  of  life.    But  the 
progression  in  the  celerity  of  the  movements  on 
the  one  hand  and  of  corporeal  development  on 
the  other,  is  unequal ;  and  there  is  but  a  single 
epoch  in  the  whole  course  of  childhood  when 
such  an  equality  or  balance  exists,  and  at 
which  consequently  the  temperature  of  the 
child  is  the  same  as  that  of  the  adult.  Previous 
to  this  epoch,  the  nutritive  and  nervous  func- 
tions are  so  imperfectly  developed,  that  their 
influence,  inimical  to  the  production  of  heat, 
surpasses  the  favourable  tendency  to  this  end, 
which  we  have  in  the  celerity  of  the  motions  of 
circulation  and  respiration.    It  follows  that  the 
temperature  of  the  body  is  inferior  at  the  pre- 
ceding limit  or  to  that  of  the  adult  state  ;  with 
the  progress  of  time,  however,  the  child  attains 
this  limit,  and  then  we  have  a  new  relation 
established.    The  evolution  of  the  nutritive  and 
nervous  functions  continues,  and  although  it 
have  not  yet  attained  its  ultimate  term,  the  de- 
fect of  heat  which  results  from  this  is  all  but 
compensated  by  the  celerity  of  Use  motions, 
which  is  still  sufficiently  great,  to  surpass  in  a 
marked  degree  the  celerity  of  the  motions  in 
the  adult.    The  temperature  at  this  period  will, 
therefore,  be  above  that  of  the  adult.    This  pe- 
riod lasts  for  several  years  in  childhood  or 
youth  ;  but  then  comes  a  gradual  retardation 
in  the  motions  both  of  respiration  and  circula- 


tion, and  with  this  a  reduction  of  the  tempera- 
ture to  the  standard  of  the  adult. 

There  are  consequently  four  states  of  the 
temperature  from  birth  up  to  adolescence  inclu- 
sive. In  the  first  period  the  temperature  is  at 
the  minimum  ;  in  the  second,  it  attains  the 
adult  degree ;  this  might  be  entitled  the  period 
of  the  mean  temperature ;  in  the  third,  the 
temperature  exceeds  that  of  the  adult;  finally, 
in  the  fourth,  it  sinks  to  the  mean,  that  is, 
the  temperature  of  the  adult. 

There  are,  therefore,  constitutions  in  the  same 
class  of  animals  which  are  more  or  less  favour- 
able to  the  production  of  heat ;  for  it  is  so 
among  individuals  that  differ  in  age  in  the 
limits  between  the  moment  of  birth  and 
that  at  which  adolescence  is  completed ;  and 
this  leads  us  to  new  considerations. 

DIFFERENCES  OF  CONSTITUTION  IN  RELATION 
WITH  THE  PRODUCTION  OF  HEAT  AMONG 
ANIMALS. 

Since  the  body  and  the  functions  are  pro- 
gressively developed,  and  without  interruption 
between  the  two  grand  periods  named,  there  is 
in  the  course  of  this  long  interval  as  much  dif- 
ference in  the  state  of  the  constitution  as  (here 
are  sensible  degrees  of  development ;  a  circum- 
stance that  implies  a  long  series  of  varieties. 
But  these  intimate  differences  are  not  mani- 
fested externally  by  corresponding  states  of 
temperature  of  body.  For  we  have  seen  that 
this  undergoes  but  four  sensible  variations  in 
this  respect,  and  that, of  these  four  modifications, 
two  were  of  like  import.  It  is  every  way 
worthy  of  attention  to  observe  that,  at  the  point 
which  separates  the  first  from  the  second  period 
of  infancy,  the  temperature  should  be  equal  to 
that  of  the  adult. 

It  is  difficult  to  imagine  that  this  equality 
can  exist  under  every  variety  of  external  cir- 
cumstance, when  we  see  that  the  elements  upon 
which  it  depends  are  so  different.  And  this 
leads  us  to  consider  the  production  of  heat 
under  a  new  point  of  view.  Under  what  cir- 
cumstances has  this  equality  of  temperature  be- 
tween the  infant  and  the  adult  been  observed  ? 
It  was  when  the  external  temperature  was  mild 
or  even  warm.  "Would  the  same  thing  have 
been  observed  had  this  been  cold  or  severe  ? 
It  is  evident  that  if  the  faculty  to  produce  heat 
is  the  same  at  this  period  of  infancy  as  it  is  in 
adult  age,  the  heat  of  the  body  will  always  re- 
main the  same,  making  abstraction  of  the  diffe- 
rences that  depend  on  those  of  simple  corpo- 
real bulk.  Thus,  all  things  else  being  equal,  a 
young  animal  at  this  epoch  ought  to  cool  to  the 
same  degree  as  an  adult  under  the  influence  of 
external  cold,  if  it  have  the  same  power  of  pro- 
ducing heat.  Tf,  however,  it  be  inferior  in  its 
calorific  powers,  it  will  not  be  competent  to 
maintain  its  temperature  to  the  same  degree  as 
the  adult,  and  it  will  fall  under  this  limit  in  a 
proportion  determined  by  the  difference  which 
exists  in  the  faculty  of  producing  heat.  On 
making  application  of  the  principles  which 
have  been  already  announced,  let  us  try  if  we 
cannot  predict  the  effects.  By  reason  of  the 
inferiority  in  energy  of  the  nervous  system  in 


668 


ANIMAL  HEAT. 


early  life,  it  is  difficult  to  suppose  that  a  young 
animal  will  resist  the  action  of  intense  cold  in 
the  same  manner  as  an  adult.  This  inference 
is  fully  borne  out  by  the  following  experiment. 
A  young  guinea-pig  a  month  old,  the  tempe- 
rature of  whose  body  was  high  and  steady,  the 
temperature  of  the  external  air  being  mild,  was 
exposed  along  with  an  adult  to  the  same  degree 
of  diminished  temperature — the  air  was  at  6°c. 
(32°  F.).  In  the  course  of  an  hour  the  young 
creature  had  lost  9°  c.  in  temperature,  whilst 
the  adult  had  only  lost  2°,.5  c.  This  experi- 
ment, repeated  several  times  with  the  same 
species  of  animal,  always  gave  the  same  result. 
Young  and  adult  birds  of  the  same  species, 
treated  in  a  similar  manner,  showed  the  same 
diversity  in  their  powers  of  resisting  the  effects 
of  external  cold,  from  which  we  may  infer  that 
the  law  is  quite  general.  Several  young  mag- 
pies, for  instance,  whose  temperature  was  sta- 
tionary in  a  mild  spring  atmosphere,  were 
placed  with  an  adult  in  air  cooled  to  +4°c. 
After  the  lapse  of  twenty  minutes,  one  of  the 
young  ones  was  found  to  have  lost  14°  of  tem- 
perature. The  others,  examined  at  intervals, 
none  of  which  exceeded  one  hour  and  ten  mi- 
nutes in  length,  had  cooled  from  14°  to  16°  c. 
The  adult  bird,  on  the  contrary,  similarly  cir- 
cumstanced, did  not  suffer  a  greater  depression 
of  temperature  than  3°  c.  The  loss  of  heat 
sustained  by  the  young  birds  was  so  great  as  to 
be  incompatible  with  life,  if  continued  ;  that 
endured  by  the  old  one  was  trifling  in  amount, 
and  not  inconsistent  with  health.  It  is  quite 
true  that  the  difference  in  point  of  size  and 
quantity  of  plumage  has  an  influence  upon  this 
inequality  of  cooling  ;  but  at  the  period  of  de- 
velopment, when  the  experiment  was  tried,  the 
difference  was  not  remarkable  in  regard  to 
either  point ;  nevertheless  it  is  only  proper  to 
take  notice  of  it.  By  prolonging  the  period 
during  which  the  adults  were  exposed  to  the 
cooling  process,  the  advantages  they  derive 
from  their  greater  size  and  closer  plumage  may 
be  counterbalanced  or  compensated.  It  is  es- 
sential to  observe  that  in  the  course  of  the  fust 
hour  the  adult  bird  had  only  lost  temperature 
in  the  proportion  of  one-fifth  of  that  lost  by  the 
young  birds,  which  obviously  bears  no  ratio  to 
the  difference  in  point  of  size,  plumage,  &c. 
And  then,  the  operation  of  the  cold  being  con- 
tinued, the  adult  suffered  no  further  depres- 
sion of  temperature  :  it  fell  three  degrees  cen- 
tigrade, and  then  became  stationary.  We  can- 
not, therefore,  ascribe  the  entire  difference  in 
the  cooling  to  that  of  the  physical  conditions  of 
size  and  plumage  ;  a  difference  of  constitution 
must  go  for  a  great  deal ;  there  are  inherent 
diversities  of  constitution,  favourable  or  the  re- 
verse, to  the  production  of  heat.  The  truth  of 
this  conclusion  appears  much  more  clearly  if 
we  continue  to  subject  young  birds  to  the  same 
kind  of  experiment  at  successive  epochs  not  so 
close  to  one  another.  The  rapid  progress  they 
make  in  the  power  of  evolving  heat  is,  indeed, 
a  very  remarkable  fact.  A  few  days  later,  and 
they  lose  temperature  in  a  much  less  considera- 
ble degree  when  exposed  to  cold  under  the 
same  circumstances,  although  there  was  little 


or  no  apparent  difference  in  the  external  appear- 
ance of  the  birds.  And  this  is  a  new  and  con- 
vincing proof  that  the  inequality  in  the  disposi- 
tion to  lose  heat  obvious  at  different  periods 
of  life  under  exposure  to  a  low  external  tempe- 
rature, is  principally  owing  to  inherent  inequa- 
lity in  the  faculty  of  producing  caloric. 

It  is  of  great  importance  that  a  precise  idea 
be  formed  of  this  expression.  Up  to  a  very 
recent  period  in  the  investigation  of  animal 
heat,  no  one  thought  of  comparing  animals 
save  with  reference  to  the  temperature  of  their 
bodies  only  :  and  when  it  was  found  that  this 
was  the  same  or  different  by  so  much,  the  ac- 
count was  closed,  the  comparison  was  pushed 
no  farther,  under  the  impression  that  every 
thing  was  included  under  this  single  ostensible 
character.  Undoubtedly,  it  must  be  granted 
that,  all  else  being  alike,  equality  of  tempera- 
ture is  an  indication  of  equality  in  the  capacity 
to  produce  heat.  But  animals  in  one  set  of 
circumstances  may  actually  produce  the  same 
quantity  of  caloric,  and  not  continue  to  do  this 
the  circumstances  being  changed.  It  is  of 
consequence  to  distinguish  the  actual  produc- 
tion, from  the  power  to  produce  under  different 
conditions.  The  one  is  an  act,  the  other  a  fa- 
culty, a  distinction  of  the  highest  importance  in 
philosophical  language  in  general,  and  espe- 
cially in  that  of  physiology.  But  animals  of 
the  same  size,  subjected  to  the  same  variations 
of  external  conditions,  if  they  continue  to  ex- 
hibit corresponding  degrees  of  temperature, 
whether  these  are  higher  or  lower,  have  evi- 
dently the  same  faculty  of  producing  heat.  If, 
on  the  contrary,  they  present  different  degrees 
under  the  influence  of  precisely  similar  exter- 
nal variations  of  circumstance,  it  is  obvious 
that  they  must  possess  the  faculty  of  producing 
heat  in  different  degrees.  Unless  we  be  actu- 
ally persuaded  of  the  value  of  this  expression, 
so  simple  in  other  respects,  and  so  constantly 
held  in  view  in  all  analogous  circumstances, 
the  study  of  the  phenomena  of  animal  heat 
would  remain  as  it  were  barren,  whilst  the  in- 
vestigation of  the  diversities  of  constitution  in 
relation  with  this  faculty  is  fertile  in  interesting 
and  useful  applications. 

We  have  seen  how  constitutions  differed  in 
this  respect  according  to  age  in  the  earlier 
period  of  life  and  in  the  adult  state.  It  is 
probable  that  there  are  other  varieties  depend- 
ent on  other  causes ;  for  example,  differences 
of  season,  climate,  &c.  This  point  it  will  be 
our  next  business  to  examine. 

INFLUENCE    OF    SEASONS    IN    THE  PRODUC- 
TION   OF    ANIMAL  HEAT. 

The  temperature  of  an  animal  is  the  result, 
1st,  of  the  heat  which  it  produces  ;  2d,  of  that 
which  it  receives  ;  3d,  of  that  which  it  loses. 
The  proportion  of  heat  which  is  lost  depends 
on  two  principal  conditions,  the  relatively 
colder  temperature  of  the  atmosphere,  and  the 
amount  of  evaporation  that  takes  place  from 
the  surface  of  the  animal.  In  cold  and  tem- 
perate climates  these  two  conditions  of  cooling 
are  in  inverse  relations  to  one  another  in  the 
opposite  seasons  of  winter  and  summer.  In 


ANIMAL  HEAT. 


669 


winter  the  temperature  of  the  air  is  lower  ;  in 
summer  the  amount  of  evaporation  greater. 
These  two  conditions  of  refrigeration,  therefore, 
tend  to  compensate  one  another,  and  conse- 
quently to  maintain  the  equilibrium  of  tempe- 
rature as  regards  the  body  in  the  two  opposite 
seasons.  They  have  unquestionably  a  consi- 
derable share  in  this  business  ;  and  it  was  long 
believed  that  the  simple  difference  indicated  in 
the  external  conditions  sufficed  to  preserve  the 
temperature  of  the  body  alike  during  the  two 
periods.  But  in  reflecting  on  the  phenomena 
presented  by  cold-blooded  animals  with  the 
changes  of  the  seasons,  which  have  already 
been  spoken  of  at  length,  we  find  such  an  opi- 
nion or  view  to  be  inadmissible.  For  in  ex- 
amining those  species  of  cold-blooded  animals 
which  from  their  structure  are  liable  to  lose 
more  by  evaporation  than  any  other  animal, 
we  see  that  no  such  compensation  takes  place. 
Frogs,  lor  example,  the  skin  of  which  is  so  soft 
and  permeable,  and  whose  bodies  besides  are 
so  succulent  that  they  must  be  presumed  in  the 
most  favourable  circumstances  to  sustain  loss 
by  evaporation,  ought  to  preserve  the  same 
temperature  in  winter  and  in  summer  if  the 
low  temperature  in  winter  were  compensated 
by  the  excess  of  evaporation  in  proportion  as 
the  heat  of  the  season  augments.  But  we 
know  that  the  temperature  of  these  creatures 
follows,  to  a  very  great  extent,  that  of  the  at- 
mosphere, between  0°  and  25°  c.  (32°  and  77° 
F.),  diffeiing  at  no  time  from  it  by  more  than  a 
degree  or  two.  The  phenomenon  here  is  sim- 
ple, by  reason  of  the  slight  evolution  of 
caloric  by  the  frog,  and  leaves  no  doubt  upon 
the  mind.  We  must,  therefore,  have  recourse 
to  other  conditions,  in  order  to  explain  the 
slight  difference  that  is  observed  in  the  summer 
and  winter  temperature  of  man  and  other  warm- 
blooded animals.  Since  external  conditions 
do  not  appear  to  explain  the  phenomena,  it 
must  undoubtedly  mainly  depend  oncertain 
changes  effected  in  the  animal  itself.  Now, 
since  the  internal  conditions  which  influence 
the  temperature  of  the  body  are  those  also  that 
regulate  the  production  of  heat,  it  is  here  that 
the  change  must  be  effected. 

It  is  obvious  that  the  cause  of  refrigeration 
in  winter  being  more  active,  to  meet  the  greater 
expenditure  there  must  be  the  means  provided 
for  furnishing  a  larger  supply — the  calorific 
faculty  must  be  more  active  in  winter  than  in 
summer.  Hie  inverse  of  this  takes  place  in 
summer ;  so  that  the  temperature  of  the  body 
in  the  two  seasons  is  determined  in  the  follow- 
ing manner: — in  winter  there  is  a  more  active 
production  with  a  greater  loss ;  in  summer  a 
less  production,  with  a  smaller  loss  of  heat.  In 
this  way  is  there  compensation,  and  a  perfect 
equilibrium  maintained  at  all  seasons.  To 
render  this  relation  more  evident,  it  may  be 
expressed  in  another  manner  ;  as,  for  example, 
in  summer  the  body  receives  more  heat  from 
without,  and  produces  less ;  in  winter  it  receives 
less  and  produces  more. 

These  considerations  carry  us  farther.  As 
this  difference  in  the  production  of  heat  lasts  as 
long  as  the  various  seasons,  and  lakes  place 


progressively,  it  is  to  be  presumed  that  it  be- 
longs to  an  intimate  and  more  or  less  en- 
during change  effected  in  the  state  of  the 
body.  In  other  words,  the  constitution  alters, 
and  the  faculty  of  producing  heat  changes  in 
the  same  degree.  The  fact  thus  expressed  is 
immediately  susceptible  of  an  interesting  ap- 
plication. If  the  faculty  of  producing  heat  is 
less  in  summer,  the  temperature  of  the  body 
will  not  be  maintained  to  the  same  point  in  the 
two  seasons  under  sudden  exposure  to  the 
same  degree  of  cold.  By  subjecting  animals 
to  the  test  of  experiment  in  the  two  seasons,  it 
is  easy  to  judge  of  the  justice  of  the  preceding 
deductions,  as  well  as  of  the  principles  which 
led  to  them.  To  have  the  mode  of  refrigera- 
tion precisely  the  same,  attention  must  be  had 
not  merely  to  the  thermometric  temperature  of 
the  air,  but  also  to  its  humidity,  which  ought 
to  be  the  same  in  both  instances.  A  difference 
in  the  hygrometric  state  of  the  air  will  certainly 
produce  a  difference  in  the  effects  of  refrigera- 
tion. The  apparatus  employed  consisted  of 
earthen  vessels  plunged  amidstaquantity  of  melt- 
ing ice.  Air  thus  cooled  soon  reaches  the  point 
of  extreme  humidity.  The  air  being  at  zero  c. 
(32°  F.),  the  animal  is  introduced,  placed  upon 
a  stage  of  gauze  to  prevent  its  coming  in  con- 
tact with  the  moist  and  rapidly  conducting 
surface  of  the  vessel.  A  cover,  also  piled  over 
with  ice,  is  then  placed  over  the  apparatus,  but 
so  arranged  as  still  to  permit  the  ready  reno- 
vation of  the  air  contained  in  the  interior. 
Still  farther  to  secure  the  purity  of  the  included 
air,  a  solution  of  potash,  which  of  course  ab- 
sorbed the  carbonic  acid  produced  with  avidity, 
occupied  the  bottom  of  the  vessel.  In  winter, 
in  the  month  of  February,  the  experiment  was 
made  at  the  same  time  upon  five  adult  spar- 
rows, which  were  all  included  in  the  apparatus. 
At  the  end  of  an  hour  they  were  found  one 
with  another  to  have  lost  no  more  than  0°,  4  c, 
or  less  than  half  a  degree ;  some  of  them 
having  suffered  no  depression  of  temperature 
whatsoever,  others  having  lost  as  much  as,  but 
none  more  than,  1°  c.  The  temperature  of  the 
whole  then  remained  stationary  to  the  end  of 
the  experiment,  which  was  continued  for  three 
hours.  In  the  month  of  July  the  same  expe- 
riment was  performed  upon  four  full-grown  or 
adult  sparrows.  The  temperature  of  these 
birds  at  the  end  of  an  hour  had  undergone  a 
depression,  the  mean  term  of  which  was  3°, 
62,  and  the  extremes  6°,  5  and  2°  c.  At  the 
end  of  the  third  hour  the  mean  term  of  the 
refrigeration  suffered  was  6°,  the  extremes  being 
12°  and  3°,  5  c.  It  ought  to  have  been  stated 
that  in  the  experiment  in  the  winter  month, 
the  birds  had  been  for  some  time  kept  in  a 
warm  room,  so  that  the  sudden  transition  was 
the  same  in  both  instances,  in  the  winter  as 
well  as  the  summer  experiment.  The  diver- 
sity in  the  constitution  of  these  birds,  conse- 
quently, with  reference  to  the  powers  of  pro- 
ducing heat,  was  an  effect  of  the  difference  of 
the  seasons.  Each  month  the  temperature  of 
which  differs  in  any  degree  from  that  of  the 
month  before  or  after  it,  has  an  obvious  ten- 
dency to  modify  the  temperament  or  constitu- 


670 


ANIMAL  HEAT. 


tion  in  the  manner  which  has  been  indicated. 
In  summer  we  may  presume,  nay  we  may  be 
certain,  that  the  differences  obtain  in  degree 
according  to  the  mean  intensity  of  the  heat 
proper  to  each.  This  is  even  to  be  proved  by 
direct  experiment.  The  month  of  August,  as 
commonly  happens,  was  not  so  hot  as  the 
month  of  July,  and  six  sparrows  treated  in  the 
same  manner  as  those  that  were  the  subject  of 
the  July  experiment  already  detailed,  were 
found  not  to  suffer  refrigeration  to  the  same 
extent.  After  the  lapse  of  an  hour  the  mean 
temperature  of  the  six  had  sunk  1°,  62,  and 
after  three  hours  4°,  87  c,  from  which  it  is  ob- 
vious that  with  the  successive  declensions  of  the 
external  temperature  the  faculty  of  engendering 
heat  increases.  This  is  demonstrated  by  the 
experiments  quoted.  The  animals  that  were 
the  subjects  employed  suffered  a  relatively  less 
degree  of  refrigeration  in  the  cooler  month  than 
they  had  done  in  the  hotter,  when  exposed  to 
the  same  measure  of  cold.  In  the  first  set  of 
experiments  performed  in  one  of  the  coldest 
months  of  the  year,  the  power  of  resisting  cold 
was  made  particularly  manifest.  The  sparrows, 
kept  for  three  hours  in  an  atmosphere  at  the 
temperature  at  which  ice  melts,  scarcely  suffered 
any  loss  of  heat  at  all.  The  results  of  the 
three  series  of  experiments  detailed  confirm,  in 
every  particular,  the  conclusions  which  had 
been  come  to  analogically  and  a  priori.  They 
do  more  than  this.  They  bear  out  equally  the 
principles  which  had  been  deduced  with  refe- 
rence to  the  constitutions  more  or  less  favoura- 
ble to  the  production  of  heat.  It  is  apparent, 
in  the  first  place,  that  the  influence  of  the 
summer  and  that  of  the  winter  act  on  the  con- 
stitution in  the  same  manner  as  the  two  opposed 
periods  of  early  youth  and  adult  age.  Let  us 
therefore  inquire  in  what  manner  these  different 
conditions  tend  to  produce  analogous  effects. 
We  have  seen  that  the  constitution  of  early  life 
differed  from  that  of  adult  age,  especially  in 
the  inferior  energy  of  the  functions  of  innerva- 
tion and  nutrition.  Now  this  is  that  which 
constitutes  or  causes  the  principal  difference 
between  the  winter  and  summer  constitution  of 
man.  We  generally  feel  ourselves  weaker  in 
summer  than  in  winter,  and  our  digestive 
powers  are  then  also  decidedly  less  vigorous. 
What  completes  the  analogy  is  that  the  motions 
of  circulation  and  respiration  are  accelerated  in 
summer;  and  as  a  complement  of  the  whole 
of  these  data,  the  temperature  is  somewhat 
higher  in  summer;  just  as  we  have  seen 
that  there  is  an  epoch  in  youth  when  the  tem- 
perature exceeds  that  which  is  proper  to  com- 
plete manhood.  Thus,  the  parity  between 
the  constitution  of  youth  (in  the  second  period 
of  childhood,)  and  that  of  the  body  in  sum- 
mer, contrasted  with  the  constitution  of  the 
adult  age  and  that  of  the  body  in  winter,  exists 
in  the  three  following  relations  : — 1st,  a  lessened 
faculty  of  producing  heat ;  2d,  greater  activity 
in  the  motions  of  circulation  and  respiration  ; 
3d,  a  higher  temperature  of  the  body. 

But  this  faculty  of  adaptation  to  the  different 
seasons  inherent  in  the  body  is  only  observed 
in  the  better  constitutions.    That  it  may  be 


manifested,  it  is  necessary  there  be  present  a 
certain  energy  of  the  nervous  system ;  without 
this  even  the  moderate  colds  of  winter  will  not 
be  resisted.  Without  this  the  adult  will  have 
a  constitution  that  will  present  analogies  with 
that  of  early  infancy.  At  present  we  merely 
mention  the  kind  of  constitution ;  we  shall 
return  to  the  subject  by-and- by. 

Differences  according  to  the  nature  of  the 
climate. — The  preceding  facts  render  direct  ex- 
periments to  ascertain  the  influence  of  the  tem- 
perature of  different  climates  on  the  calorific 
power  altogether  unnecessary.  This  is  so  far 
fortunate  ;  for  it  were  no  easy  matter  to  institute 
them  to  the  extent  and  with  the  precautions 
necessary  to  security  and  satisfaction.  The 
knowledge  of  these  effects  is  a  necessary  con- 
sequence of  the  researches  that  precede.  The 
temperature  of  warm  climates  is  represented  by 
the  summer  temperature  of  temperate  climates, 
with  this  difference,  that  it  is  higher,  and  that 
with  slight  variations  it  continues  through  the 
whole  year.  Whence  it  follows  that  warm 
climates  taken  generally  must  produce  effects 
upon  the  constitution  analogous  to  those  pro- 
duced by  summer  with  us,  only  of  greater 
intensity  by  reason  of  the  higher  thermometric 
range  and  longer  continuance  of  the  heat.  The 
inhabitants  of  hot  climates  ought  consequently 
to  have  an  inferior  degree  of  calorific  power 
than  those  of  temperate  or  cold  countries,  what- 
ever be  the  season.  And  we  find,  in  fact,  that 
the  natives  of  the  warmer  latitudes  of  the  earth 
present  the  characters  in  general  that  distinguish 
the  constitution  of  the  body  in  the  summers  of 
temperate  countries,  and  characterizes  the  second 
period  of  youth — more  rapid  motions  of  the 
circulatory  and  respiratory  systems,  and  a 
higher  temperature,  conjoined  with  an  inferior 
degree  of  energy  in  the  functions  of  innervation 
and  nutrition. 

We  shall  not  here  enter  upon  the  examina- 
tion of  the  effects  upon  the  natives  of  these 
warmer  latitudes  from  change  of  climate.  We 
shall  speak  of  this  elsewhere.  After  the  periodi- 
cal changes  depending  on  the  seasons  we  shall 
pass  to  others  of  shorter  duration,  but  which 
revert  much  more  frequently,  and  are  under  the 
influence  of  other  causes. 

INFLUENCE    OF   SLEEP   ON    THE  PRODUCTION 
OF  HEAT. 

In  the  course  of  the  twenty-four  hours  the 
body  is  in  two  very  different  and  in  some  sort 
opposite  states  —  the  states  of  sleeping  and 
watching.  These  two  states  are  principally 
contrasted  in  the  energy  and  weakness  of  the 
nervous  system:  from  a  perfect  consciousness 
of  all  that  is  passing,  we  suddenly  observe  a 
complete  suspension  of  this  office  in  the  whole 
circle  of  the  functions  of  relation.  At  the  same 
time  the  motions  of  the  circulatory  and  respira- 
tory system  become  slower.  No  more  is  needed 
to  lead  to  the  conclusion  that  in  this  state  the 
temperature  must  be  lower;  this  is  an  inference 
we  draw  without  risk  of  error.  But  the  degree 
in  which  these  motions  are  retarded  is  ex- 
tremely limited ;  and  the  depression  of  tem- 
perature must  be  expected  to  be  in  the  same 


ANIMAL  HEAT. 


671 


proportion :  it  is  in  fact  very  slight,  although 
appreciable.  What  would  happen  were  the 
retardation  in  the  important  motions  mentioned 
more  considerable?  The  temperature  would 
suffer  a  corresponding  and  great  depression, 
and  various  consequences  might  be  conceived 
as  calculated  to  ensue.  If  the  degree  of  cold 
did  no  injury  to  the  economy,  the  sleep  would 
last  the  time  required  to  repair  by  rest  the 
energy  which  the  nervous  system  had  dissipated 
or  lost  by  its  activity  during  the  period  of 
watching.  If,  on  the  contrary,  the  refrigeration 
attained  a  considerable  degree,  it  would  by  the 
consequent  pain  stimulate  the  nervous  system 
so  much  as  to  cause  it  to  wake  up  to  general 
consciousness;  but  in  case  the  nervous  system 
were  not  in  a  condition  to  feel  this  excitement, 
in  other  words  to  re-act  and  produce  waking, 
it  would  sink  into  the  state  of  lethargy. 

These  divers  states  which  we  deduce  as  pos- 
sibilities, as  what  might  be  expected  to  occur 
in  sleep  according  to  the  relations  of  the  func- 
tions, do  in  fact  present  themselves  frequently 
in  nature.  It  commonly  enough  happens  that 
we  are  aroused  from  our  sleep  by  a  feeling  of 
cold,  although  the  external  temperature  has 
not  changed.  With  regard  to  the  lethargic 
state,  although  it  certainly  occurs  but  rarely, 
still  it  has  been  acknowledged  by  the  most 
respectable  authorities,  and  its  occasional  occur- 
rence seems  indubitable.  That,  however,  which 
is  rare  as  regards  man  may  be  common  and 
even  usual  as  animals  are  concerned. 

Phenomena  presented  by  hybernating  animals 
with  regard  to  the  production  of  heat. — If 
during  the  height  of  summer  and  during  the 
state  of  watching  a  dormouse  or  a  bat  be  exa- 
mined as  to  their  temperature,  this  will  be 
found  the  same  as  that  of  many  other  warm- 
blooded animals.  But  if  either  of  these  animals 
be  examined  whilst  asleep  at  the  same  season 
of  the  year,  the  temperature  will  be  found 
to  have  declined  considerably.  These  changes 
have  been  determined  by  Dr.  Marshall  Hall, 
to  whom  we  are  indebted  for  manv  ob- 
servations of  high  interest  upon  the  state  of 
the  circulation  in  hybernating  animals.  The 
writer  also  observed  the  same  diversities  in 
the  temperature  of  these  animals  according  to 
their  state  of  sleep  or  watching;  but  he  had 
not  published  his  observations  at  the  time  Dr. 
Hall's  paper  appeared.  Here,  then,  we  have 
several  species  of  warm-blooded  animals  which, 
during  the  hottest  season  of  the  year,  exhibit 
in  the  two  states  of  sleep  and  watching  a  very 
marked  contrast  in  regard  to  the  temperature  of 
their  body,  which  is  high  during  the  waking 
period,  low  during  that  of  sleep,  the  external 
temperature  having  no  part  in  the  phenomena. 
The  difference  of  temperature  coincides  very 
evidently  with  the  state  of  the  nervous  system — 
its  energy  in  watching,  its  enfeeblement  in 
sleep — a  state  which  we  have  already  seen  to 
influence  in  a  very  great  degree  the  rapidity  of 
the  motions  of  circulation  and  respiration, 
which  are  accelerated  during  the  energetic  con- 
dition, retarded  during  the  period  of  inaction. 
A  higher  temperature  in  the  one  case  and  a 


lower  temperature  in  the  other  are  necessary 
consequences. 

These  facts  are  interesting  under  two  points 
of  view.  1st,  They  show  precisely  the  kind  and 
extent  of  the  influence  which  the  states  of 
watching  and  sleep  exert  in  general  on  the 
production  of  heat  in  animal  bodies;  2d,  they 
are  remarkable  in  the  particular  instances  under 
consideration,  in  this,  that  the  differences  exhi- 
bited during  the  two  states  are  extreme.  It 
must  be  allowed,  therefore,  that  those  animals 
in  which  they  take  place  must  have  less 
energetic  nervous  systems  than  other  warm- 
blooded animals.  From  this  tendency  in 
the  animal  economy,  there  must  also  be  in 
different  species  a  diversity  rather  than  an 
equality  in  the  degree  in  which  the  phenomena 
are  exhibited.  And  this  is  confirmed  by  obser- 
vation. Some  cool  to  a  much  greater  extent 
than  others  during  their  sleep  in  the  summer 
season.  They  may  be  said  severally  to  have 
just  as  much  nervous  energy  as  is  requisite  to 
sustain  a  high  temperature  in  the  summer 
season  during  their  state  of  highest  activity, 
i.  e.  during  the  period  of  watching,  and  no 
more.  When  the  state  of  excitement  ceases, 
and  the  collapse  that  follows  excitement 
supervenes,  the  languor  manifested  is  much 
greater  than  that  of  other  animals  in  the 
same  condition,  and  their  temperature  sinks 
in  proportion.  The  energy  possessed  by  hyber- 
nating animals  seems  barely  sufficient  to  enable 
them  during  the  summer  season  to  maintain  a 
temperatureof  body  equal  tothatof  warm-blood- 
ed animals  in  general.  They  subsequently  pre- 
sent another  phenomenon  with  regard  to  their 
temperature  well  worthy  of  particular  attention, 
although  it  be  no  more  than  a  consequence  of  the 
first.  Since  it  is  a  defect  of  energy  in  the 
nervous  system  during  sleep  which  prevents 
their  maintaining  the  degree  of  rapidity  in  the 
motions  of  circulation  and  respiration  so  essen- 
tial in  their  turn  to  the  maintenance  of  a  tem- 
perature of  the  body  but  little  inferior  to  that 
pertaining  to  the  state  of  watching  in  summer, 
how  are  they  to  preserve  their  temperature  even 
during  the  watching  state  when  the  summer 
declines  into  autumn,  and  the  autumn  into 
winter? 

It  is  evident  that  if  they  follow  the  general 
rule  their  respiratory  and  circulatory  motions 
will  be  retarded  with  the  fall  of  the  atmospheric 
temperature,  and  this  by  so  much  the  more  as 
their  nervous  system  shows  a  less  degree  of 
energy.  It  is  even  presumable  that  owing  to 
the  decline  of  atmospheric  temperature  in 
autumn,  they  will  exhibit  a  temperature  of 
body  during  the  period  of  watching  analogous 
to  that  which  they  manifest  in  the  heat  of  the 
summer  season  during  sleep.  And  this  is  pre- 
cisely what  happens.  M.  de  Saissy  paid  par- 
ticular attention  to  the  state  of  these  animals 
at  intervals  from  the  month  of  August  onwards. 
On  the  6th  of  August,  the  temperature  of  the 
air  being  at  22°  c.  (72°  F.),  a  dormouse  and  a 
marmot  marked  36°  5  (98°  F.),  and  a  hedge- 
hog 34°  c.  (93°,  5  F.)  in  the  axilla.  On  the 
23d  September,  the  external  temperature  being 


672 


ANIMAL  HEAT. 


18°  (64°,  5  F.),  the  temperature  of  the  hedge- 
hog was  lower  by  2°  c,  that  of  the  marmot  by 
5°,  25  c,  and  that  of  the  dormouse  by  5°,  5  c. 
than  it  had  been  at  the  previous  date.  This  is 
a  considerable  depression,  if  it  be  remembered 
that  the  decline  in  the  atmospheric  temperature 
was  by  no  means  considerable ;  that  the  air  was 
in  fact  still  at  a  point  which  made  it  be  felt  as 
warm  to  the  generality  of  persons.  The  same 
individual  animals  examined  on  the  7th  of 
November,  the  atmospheric  temperature  being 
7°,  presented  the  following  state.  The  mar- 
mot had  lost  9°,  25  c,  the  dormouse  15°,  5  c, 
and  the  hedge-hog  21°,  25  c.  of  their  respec- 
tive temperatures  during  the  month  of  August, 
so  that  their  absolute  temperatures  were  now 
as  follows:  that  of  the  marmot  27°  (81°  F.), 
that  of  the  dormouse  21°  (70°  F.),  and  that  of 
the  hedge-hog  13°,  75  c.  (57°  F.).  Here,  there- 
fore, we  have  several  warm-blooded  animals 
which  in  autumn  approach  very  closely  to  the 
cold-blooded  tribes  with  regard  to  their  calorific 
power. 

If  they  be  next  observed  during  the  period 
of  sleep,  the  relationship  will  be  observed  if 
possible  in  a  more  striking  degree.  If,  during 
the  state  of  watching,  they  surfer  such  a  loss  of 
temperature  as  has  been  specified  with  the 
gradual  decline  of  the  temperature  of  the  year, 
they  will  certainly  suffer  still  more  remarkable 
changes  during  the  state  of  sleep,  in  conforinity 
with  the  principles  already  fully  developed. 
The  sleep  of  these  animals  will  also  become 
longer  and  deeper  in  proportion  as  the  nervous 
system  loses  its  power,  under  the  influence  of 
the  external  cold,  a  loss  which  will  be  mani- 
fested by  a  farther  retardation  in  the  motions  of 
circulation  and  respiration.  But  what  is  the 
increasing  weakness  of  the  nervous  system 
during  sleep  but  a  more  or  less  marked  state 
of  torpor  ?  The  same  degree  of  cold  con- 
tinuing, or  the  degree  of  cold  becoming  gra- 
dually greater,  the  disproportion  as  regards  the 
animal  will  increase  also,  and  will  necessarily 
attain  a  term  at  which  the  torpor  during 
sleep  will  become  lethargic.  If  the  external 
temperature  goes  on  declining,  and  attains  a 
point  at  which  it  becomes  dangerous  to  the  life 
of  the  creature,  the  cold,  within  certain  limits, 
ought  to  have  the  power  of  withdrawing  the 
animal  from  its  state  of  lethargy.  The  excite- 
ment which  appertains  to  the  waking  period, 
by  accelerating  the  motions  of  circulation  and 
of"  respiration,  will  then  cause  the  temperature 
of  the  body  to  rise.  But  if  the  external  tem- 
perature does  not  become  more  favourable,  or 
if  the  animal  finds  no  means  of  abstracting 
itself  from  its  influence,  it  has  not  sufficient 
resource  within  itself  and  must  perish. 

We  have  seen  above  that  the  changes  in  the 
seasons  produced  great  modifications  in  the 
constitution  of  wann-blooded  animals  in  gene- 
ral. But  it  were  difficult  to  imagine  any  greater 
or  more  striking  than  those  presented  to  us  by 
the  species  which  we  have  just  named,  which 
belong  to  the  family  of  hybernating  animals ; 
changes  which  arise  from  their  passing  the 
winter  months  in  a  state  of  lethargy.  When 


these  animals  are  recalled  from  this  state  to- 
wards the  end  of  autumn,  and  during  the 
course  of  the  winter,  they  may  seem  to  resume 
the  characters  which  distinguish  the  vitality  of 
warm-blooded  animals  in  general,  but  they  are 
in  a  very  different  state  at  this  epoch  from  what 
they  are  in  summer.  Their  constitution  has 
un  !ergone  important  changes,  which  it  is 
necessary  to  examine  and  appreciate  exactly. 
These  changes  are  inversely  as  those  which  the 
most  perfectly  constituted  warm-blooded  ani- 
mals experience.  These,  under  the  influence 
of  the  increasing  cold  of  autumn  and  winter, 
acquire  new  vigour,  and  their  faculty  of  pro- 
ducing heat  increases  in  consequence.  Those, 
on  the  contrary,  naturally  much  less  energetic 
even  at  the  most  favourable  period  of  the  year, 
require  to  be  excited  and  supported  by  the 
high  temperature  of  the  summer  or  warmer 
months,  to  permit  them  to  exhibit  all  their 
activity  and  strength.  It  is  in  the  warm  season 
of  the  year  that  these  animals  have  the  greatest 
degree  of  energy — energy  which  has  a  certain 
duration  even  after  the  external  conditions 
which  have  developed  it  have  ceased  to  operate  ; 
for  they  have  been  as  it  were  tempered  by  the 
continuity  of  favourable  circumstances,  espe- 
cially of  the  high  atmospheric  temperature. 
This  is  the  reason  why  they  are  so  slightly 
affected  by  the  diurnal  variations  of  the  warm 
season  of  the  year;  and  even  when  this  begins 
to  wane,  and  they  are  no  longer  stimulated  by 
the  temperature  proper  to  summer,  they  find 
sufficient  energy  in  the  store  accumulated,  as 
it  were,  during  the  fine  season  to  enable  them 
to  resist  for  a  time  and  to  a  certain  extent  the 
unfavourable  influences  with  which  they  begin 
to  be  surrounded.  These  continuing,  however, 
and  even  increasing,  they  gradually  yield  to 
their  influence,  and  sink  lethargic,  till  revived 
by  the  return  of  spring  with  its  milder  tempe- 
rature. Their  languor  even  augments  not  only 
with  a  progressively  lower  degree  of  atmospheric 
temperature,  but  with  the  persistence  of  a 
degree  which  in  itself  is  not  by  any  means 
excessive. 

These  hybernating  animals,  whilst  they  pre- 
sent the  structure  of  the  warm-blooded  tribes 
in  general,  still  approach  in  a  very  remarkable 
degree  to  the  cold-blooded  tribes  in  their 
defective  energy,  or  their  indifferent  powers  of 
reaction.  This  is  to  be  regarded  as  the  prin- 
cipal source  of  the  phenomena  they  exhibit  in 
the  current  of  the  year,  phenomena  which 
are  unknown  among  the  more  perfectly  con- 
stituted warm-blooded  animals,  but  which  are 
absolutely  of  the  same  nature  as  those  presented 
by  the  cold-blooded  Vertebrata  in  the  same 
circumstances,  and  which  only  differ  in  degree. 
This  analogy  or  resemblance  in  the  phenomena 
appears  to  arise  from  analogy  not  of  structure 
but  of  constitution.  Very  opposite  organiza- 
tions may  have  analogous  constitutions ;  cold- 
blooded animals  for  example  present  the 
greatest  diversities  of  structure,  and  all  are 
affected  and  bear  themselves  in  the  same  man- 
ner under  similar  circumstances  in  very  many 
respects.    They  have  thus  a  common  constitu- 


ANIMAL  HEAT. 


673 


tion  which  characterizes  them,  the  fundamental 
principle  or  distinguishing  feature  of  which  is 
a  defect  of  energy,  or  of  power  of  reaction. 
This  principle,  so  simple  in  itself,  and  which 
is  but  the  true  expression  of  the  various  facts 
reduced  to  unity,  renders  plain  and  obvious 
much  that  otherwise  appears  anomalous  or 
contradictory.  In  studying  the  phenomena  of 
animal  heat  under  new  relations,  we  shall  find 
the  confirmation  of  what  precedes. 

Of  the  system  upon  which  the  external 
temperature  acts  primarily  and  prin- 
CIPALLY. 

Our  sensations  admonish  us  that  it  is  the 
nervous  system  that  is  acted  upon  primarily  and 
principally  by  changes  of  external  temperature. 
In  the  first  place  the  impression  is  felt  instan- 
taneously ;  in  the  second  place  the  intensity  of 
the  sensation  is  in  relation  with  the  degree  of 
external  heat  or  cold  ;  in  the  third  place  the  im- 
pression is  not  limited  to  the  various  degrees  of 
the  corresponding  sensation  of  heat  or  cold  ;  it 
extends  to  the  other  faculties  of  the  nervous 
system,  increasing  or  diminishing  the  general 
or  special  sensibility  ;  in  the  fourth  place  it  acts 
powerfully  in  increasing  or  diminishing  the 
activity  of  the  muscular  system,  principally 
through  the  medium  of  the  nervous  system. 

Influence  of  temperature  on  the  vitality  of 
cold-blooded  animals. 
If  the  functions  of  respiration  and  general 
circulation  be  destroyed  by  the  excision  of  the 
lungs  and  heart  of  a  cold-blooded  animal,  of 
one  of  the  Batrachia  for  example,  life  may  still 
continue  for  a  time.  Of  the  three  principal 
systems  of  the  economy  the  only  one  then  left 
untouched  is  the  nervous  ;  so  that  the  animal 
may  be  viewed  as  living  almost  exclusively  by 
the  agency  of  this  system.  If  several  animals  in 
this  condition  be  plunged  in  water  deprived  of 
air,  they  will  live  in  it  different  spaces  of  time 
according  to  the  degree  of  its  temperature, 
the  extremes  compatible  with  their  existence 
being  zero  and  40  c.  It  is  towards  the 
inferior  limit,  zero,  that  they  live  the  longest. 
Towards  the  upper  limit  they  die  almost  im- 
mediately. Temperature,  consequently,  pre- 
sents in  the  scale  of  variations  just  mentioned 
very  remarkable  relations  with  the  vitality  of 
these  animals.  Towards  the  lower  limit  or  that 
of  melting  ice,  it  is  obviously  most  favourable  to 
life;  towards  the  upper  limit,  it  is  most  inimical 
to  life,  extinguishing  it  almost  immediately. 
Here  it  is  impossible  to  mistake  the  system 
upon  which  the  variety  of  temperature  exerts 
its  first  and  principal  effects — the  nervous 
system. 

If  respiration  only  be  annihilated  by 
plunging  these  creatures  under  water  deprived 
of  air,  the  temperature  of  which  is  caused  to 
vary  as  above,  they  will  be  found  to  present  the 
same  phenomena  according  to  the  degree  of 
the  heat  or  cold,  but  in  a  more  striking 
manner.  Temperature  in  this  case  has  the 
same  kind  of  influence,  but  the  effects  are  more 
manifest,  from  the  circulation  of  the  venous 
blood  prolonging  life  at  every  degree  short  of 


the  one  at  the  upper  limit  of  the  scale,  at  which 
life  is  extinguished  quite  as  suddenly  as  in  the 
former  instance. 

Such  are  the  direct  and  instantaneous  effects 
of  temperature  upon  the  vitality  of  cold- 
blooded animals.  But  there  are  others  which 
flow  from  its  successive  agency,  during  a  con- 
siderable length  of  time.  If  the  series  of  ex- 
periments just  quoted  be  made  in  summer, 
and  the  different  lengths  of  life  at  different 
degrees  of  temperature  of  the  frogs  immersed 
in  water  be  noted,  (between  the  limits  which  we 
have  pointed  out  above,)  and  the  same  expe- 
riments be  repeated  in  autumn,  the  length  or 
tenacity  of  life  manifested  by  the  animals  will 
be  much  greater  at  the  same  degrees  of  tem- 
perature— they  will  in  general  be  found  to  live 
twice  as  long  now  as  they  did  in  summer,  at 
corresponding  and  equal  temperatures  of  the 
medium  in  which  they  are  immersed.  The 
depression  of  atmospheric  temperature  in  the 
autumn  has  modified  their  constitution,  and 
actually  increased  their  vitality,  precisely  in 
the  manner  indicated  above.  The  slight 
effects  of  each  successive  fall  in  the  general 
temperature  have  accumulated  in  the  constitu- 
tion so  as  to  render  their  vitality  or  tenacity  of 
life  much  greater,  a  fact  which  is  made  abun- 
dantly manifest  by  the  faculty  of  the  animals 
to  remain  for  a  much  longer  time  immersed  in 
water  without  breathing  than  they  could  have 
done  in  summer.  If  a  third  series  of  experi- 
ments of  the  same  description  be  made  in 
winter,  the  tenacity  of  life  will  be  found  to 
have  increased  in  a  very  high  degree.  At  the 
same  degree  of  temperature  frogs  will  be  found 
to  live  immersed  in  water  deprived  of  its  air 
at  least  twice  as  long  in  winter  as  they  could 
have  done  in  autumn.  The  same  cause — the 
depression  of  the  atmospheric  temperature — 
has  continued  to  act  with  greater  intensity 
and  for  a  longer  period,  and  the  constitution, 
gradually  modified  by  greater  and  longer  con- 
tinued cold,  has  acquired  greater  tenacity  of 
life. 

The  opposite  effect  takes  place  with  the 
successive  rises  of  the  temperature  from  that  of 
winter  to  that  of  summer  ;  so  that  among  cold- 
blooded animals  the  maximum  of  vitality, 
i.  e.  tenacity  of  life,  corresponds  to  the  depth 
of  winter,  the  minimum  to  the  height  of  sum- 
mer. The  slight  and  from  moment  to  moment 
inappreciable  effects  produced  by  the  external 
temperature,  whether  tending  to  increase  or  to 
diminish  the  vitality,  accumulate  with  their 
repetition  through  the  period  of  each  season, 
and  produce  a  corresponding  change  in  the  con- 
stitution with  regard  to  tenacity  of  life.  These 
accumulated  effects  of  the  different  portions  of 
the  year  constitute  the  influence  of  the  seasons 
on  the  constitution  with  respect  to  many  of  the 
most  important  relations  of  life.  The  first  of 
these  we  have  just  examined  cursorily — that  is, 
the  faculty  of  living  in  air  according  to  the 
influence  of  the  actual  temperature,  or  of  that 
of  the  past  temperature,  in  other  words  the 
season  that  has  immediately  preceded.  The 
second  of  these  fundamental  relations  consists 
in  the  various  proportions  of  air  necessary  to 


674 


ANIMAL  HEAT. 


the  maintenance  of  life  according  to  their  re- 
lations with  the  temperature.  We  have  seen 
that  it  is  at  the  minimum  of  temperature  that 
the  cold-blooded  animals  possess  the  greatest 
tenacity  of  life,  as  regards  the  most  essential 
relation,  in  other  words  they  are  in  the  con- 
dition the  most  favourable  to  enable  them  to 
do  without  air;  at  this  point  they  are  in  a  state 
to  live  for  the  longest  time  without  breathing. 
It  is  obvious  that  here  they  must  require  less 
air  than  under  any  other  circumstances  ;  they 
must  necessarily  require  so  much  the  less,  as 
their  life  will  continue  longer  here  than  under 
any  other  circumstances  without  any  access  of 
air  at  all.  It  is,  however,  essential  to  appre- 
ciate duly  this  fundamental  relation,  namely, 
that  at  the  lower  limit  of  the  scale  of  tempera- 
ture mentioned,  cold-blooded  animals  require 
less  air  to  live,  and  what  is  more,  they  con- 
sume less  air  than  under  any  other  circum- 
stances, and  are  even  incapacitated  from  con- 
suming more  than  they  do.  The  minimum 
temperature  of  this  scale  consequently  is  an 
index  of  the  maximum  of  vitality  or  tenacity 
of  life,  and  at  the  same  time  of  the  minimum 
of  respiration.  In  the  same  proportion  as  the 
temperature  rises,  the  vitality  or  tenacity  of 
life  declines,  which  makes  it  necessary  that 
this  declension  should  be  compensated  by  a 
corresponding  increase  in  their  relation  with  the 
air,  in  order  that  the  vivifying  influence  of 
this  fluid  may  neutralize  the  deleterious  effects 
of  the  increase  of  heat.  And  this  is  what 
actually  happens.  With  the  rise  in  tempe- 
rature the  sphere  of  activity  of  the  respiration 
extends,  and  the  vivifying  influence  of  the  air, 
which  increases  with  the  quantity  of  the  fluid 
consumed,  compensates  the  successive  decre- 
ments in  vitality  or  tenacity  of  life,  dependent 
on  successive  increments  of  temperature.  We 
shall  therefore  express  in  a  very  few  words  this 
fundamental  relation  between  the  tempera- 
ture of  the  air  and  the  maintenance  of  life 
among  the  invertebrate  series  of  animals, — a 
relation  entirely  deduced  from  direct  experi- 
ment, which  we  can  but  refer  to  here,  but 
which  we  shall  lay  before  our  readers  with  all 
the  requisite  details  in  our  article  on  Respira- 
tion. The  rise  of  temperature  in  the  scale 
from  zero  to  40  c.  exerts  upon  the  nervous 
system  of  cold-blooded  animals  an  action  the 
tendency  of  which  is  to  diminish  its  vitality; 
the  air,  on  the  contrary,  exerts  a  vivifying  in- 
fluence on  this  system.  It  becomes  necessary, 
therefore,  to  the  maintenance  of  life  that  their 
respective  relations  with  the  economy  be  such 
that  their  effects  compensate  or  counterbalance 
each  other. 

The  principle  relative  to  the  influence  of 
temperature  on  the  vitality  of  cold-blooded 
animals  just  laid  down,  is  applicable  in  every 
particular  to  the  changes  experienced  and  the 
phenomena  presented  by  the  hybernating  tribes 
among  the  warm-blooded  series  of  animals. 
Their  vitality  changes  with  the  wane  of  the  year, 
i.  e.  under  the  influence  of  prolonged  exposure 
to  cold,  in  the  same  manner  They  are  then  in 
a  condition  to  exist  with  a  supply  of  air  by  so 
much  the  less  as  this  influence  has  been  more 


intense  and  more  protracted,;  and  precisely  as 
the  cold-blooded  tribes,  if  entirely  deprived  of 
air  in  winter,  they  will  live  for  a  much  longer 
time  in  this  deleterious  position  than  they 
would  have  done  in  summer. 

Influence  of  temperature  on  the  vitality  of 
warm-blooded  animals  and  of  man  in  the 
states  of  health  and  disease. 

These  principles  and  considerations  lead  us 
to  examine  what  happens  among  warm-blooded 
animals  in  the  same  circumstances.  There  being 
great  and  manifold  analogies  between  them  and 
the  preceding  tribe  of  animals,  there  must  also 
be  some  community  in  the  application  of  the 
principles  laid  down;  but  as  they  also  differ 
in  many  important  respects,  this  application 
must  be  correspondingly  restricted.  In  the 
first  place,  then,  there  is  complete  analogy 
between  the  one  and  the  other  with  regard  to 
the  influence  of  the  superior  thermal  limit  on 
the  vitality  of  the  nervous  system.  To  seize 
the  analogy  properly,  it  is  however  necessary 
to  regard  the  temperature  which  modifies  this 
system  in  each  series,  from  a  point  of  view  that 
is  common  to  both.  Whether  the  temperature 
proceeds  from  without  or  from  within,  we  may 
presume  that  it  will  influence  or  modify  the 
nervous  system  in  the  same  manner,  if  not 
to  the  same  degree,  inasmuch  as  this  system 
presents  differences.  Warm-blooded  animals 
having  in  general  a  high  temperature  at  all 
seasons  of  the  year,  they  must  be  compared 
in  this  respect  with  cold-blooded  animals  in 
the  height  of  summer.  On  the  one  hand,  heat 
within  certain  limits  tends  to  increase  sensibi- 
lity and  motility ;  warm-blooded  animals, 
therefore,  with  a  few  exceptions,  which  always 
present  a  high  temperature,  constantly  exhibit 
also,  with  a  few  exceptions,  a  high,  degree  of 
sensibility  and  motility.  The  same  thing  can 
only  be  said  of  the  cold-blooded  tribes  during 
the  continuance  of  the  warm  weather.  On  the 
other  hand,  again,  high  temperature  tends  to 
lessen  the  vitality  proper  to  the  nervous  system, 
or  the  faculty  of  living  without  the  agency  of 
the  ordinary  stimuli.  This  is  also  the  reason 
why,  if  respiration  be  interrupted  among  warm- 
blooded animals  at  all  times,  and  among  cold- 
blooded animals  during  the  warmer  seasons  of 
the  year,  they  all  perish  alike  speedily  or  nearly 
so.  The  difference  in  the  time  that  elapses 
before  life  is  extinct  still  depends  on,  or  is  in 
relation  with,  the  difference  of  temperature. 
For  in  the  hotter  season  of  the  year,  cold- 
blooded animals  never  attain  the  temperature  of 
the  warm-blooded  tribes,  even  in  the  most 
burning  climates  of  the  globe.  Their  nervous 
system  will  consequently  have  a  higher  degree 
of  vitality  in  the  sense  already  indicated  ;  that 
is  to  say,  they  will  not  perish  so  promptly  in 
summer  under  deprivation  of  air  ;  but  if  they 
be  immersed  in  water  at  the  mean  tempera- 
ture of  warm-blooded  animals  generally,  which 
is  about  40°  c.  (104°  F.),  they  will  die  as  sud- 
denly— (at  least  this  is  the  case  with  those  of 
small  size  upon  which  the  experiment  has  been 
made) — as  the  warm-blooded  Vertebrata  when 
deprived  of  the  contact  of  air. 


ANIMAL  HEAT. 


675 


The  analogy  on  either  hand  consists  in  the 
effects  of  temperature.  But  the  differences 
that  must  necessarily  occur  between  natures 
that  vary  in  so  many  other  respects  are  espe- 
cially encountered  in  the  dissimilar  effects  of 
cold.  Here  we  observe  a  general  compensa- 
tion which  distinguishes  in  tVie  most  marked 
manner  the  Vertebrata  having  a  constant  or  all 
but  a  constant  temperature,  from  the  hyber- 
nating  tribes  or  Vertebrata  whose  temperature 
varies,  and  the  cold-blooded  series  generally. 
The  relation  of  cold,  or  of  a  low  temperature 
relatively  to  the  standard  of  the  more  perfect 
beings  of  creation,  is  one  of  essential  impor- 
tance, and  requiring  our  most  careful  investi- 
gation. 

Cold,  as  has  been  said,  tends  to  diminish 
sensibility  and  motility;  but  cold  itself  is  per- 
ceived by  causing  a  diminution  of  the  general 
sensibility  ;  among  animals  of  superior  organi- 
zation it  even  acts  indirectly  as  a  stimulus  : 
the  blood  flows  into  the  parts  that  had  been 
chilled,  if  their  temperature  has  not  fallen 
too  low,  for  then  all  sensibility  is  extinguished 
and  reaction  never  occurs.  The  afflux  of 
blood  to  the  external  parts  is  manifested  by 
the  increased  redness ;  and  the  skin  becomes 
red  in  proportion  as  the  parts  it  covers  are 
susceptible  of  acquiring  a  high  temperature, 
such  as  the  hand.  We  have  shown  that  the 
consequence  of  the  afflux  of  blood  is  an  in- 
crease of  temperature  which  tends  to  counter- 
balance the  effects  of  the  refrigeration.  The 
compensation,  however,  is  not  perfect.  For 
m  winter  the  temperature  continues  above  that 
of  summer,  although  there  is  a  greater  pro- 
duction of  heat  in  winter  than  there  is  in 
summer,  as  we  have  shown  above. 

The  constitution  of  the  Vertebrata  having  a 
nearly  constant  temperature  differs  essentially 
in  the  power  of  reaction  it  possesses  ;  a  power 
which  cannot  better  be  expressed  than  by  the 
word  energy,  and  which  must  necessarily  be 
referred  to  the  nervous  system.  The  power  of 
reaction  under  the  influence  of  cold  is  exhi- 
bited in  two  modes  :  the  first  is  that  which  has 
just  been  mentioned,  in  which  the  stimulus  of 
the  cold  calls  the  blood  into  the  capillaries  of 
the  surface,  without  exciting  any  kind  of  vio- 
lent motions  in  the  circulating  and  respiratory 
systems ;  the  second  consists  essentially  in 
this  last  kind  of  excitement.  The  sharpness  of 
the  cold  stimulates  the  respiratory  motions, 
which  become  accelerated,  and  the  quickening 
of  the  motions  of  the  heart  follows  or  accom- 
panies those  of  the  lungs.  These  two  modes 
of  reaction  must  be  viewed  as  two  degrees  of 
the  same  power :  1st,  an  afflux  of  the  blood  to 
the  capillary  vessels ;  2d,  acceleration  of  the 
motions  of  the  thorax  and  heart.  There  is, 
however,  between  these  two  processes  a  diffe- 
rence which  it  is  of  the  greatest  conse- 
quence clearly  to  understand.  The  first,  so 
long  as  it  remains  within  certain  and  suitable 
limits,  is  a  reaction  that  maintains  the  eco- 
nomy in  a  stale  of  health.  The  second  tends 
to  produce  salutary  effects,  but  becoming  ex- 
cessive it  brings  the  body  into  a  state  of  disease. 
The  first  is  sufficient  to  enable  those  creatures 


whose  system  is  energetic  to  resist  the  effects 
of  rigorous  cold,  by  preserving  their  general 
activity  and  the  normal  state  of  their  functions. 
The  second  is  the  resource  of  those  animals, 
which,  although  of  the  same  species,  are  so 
constituted  that  the  energy  of  the  nervous  sys- 
tem is  less  than  in  the  former.  This  is  what 
occurs  universally  in  very  early  life.  It  is  a 
reaction  the  tendency  of  which  is  salutary,  but 
which  is  not  the  less  on  this  account  the 
index  and  essence  of  a  proper  pathological 
state.  It  is  one  of  the  cases  in  which  the  vis 
medicatrix  natura  is  peculiarly  and  most 
strikingly  manifested.  This  position  is  made 
singularly  evident  by  the  following  experi- 
ment:— when  a  young  bird,  bare,  or  but  scan- 
tily covered  with  feathers,  is  taken  from  the 
nest,  and  exposed  to  the  open  air,  even  in  the 
summer  season,  its  respiration  will  be  seeu  to 
be  accelerated  in  the  ratio  of  the  cold  it  expe- 
riences. It  is  peculiarly  worthy  of  remark 
that  this  salutary  reaction,  taking  place  under 
the  influence  of  the  nervous  system,  acting,  in 
the  case  quoted,  independently  of  the  will,  is 
in  a  great  measure  the  same  as  that  which  we 
bring  into  play  by  means  of  the  will  to  com- 
bat the  same  evil.  When  in  health,  for  instance, 
we  are  exposed  to  and  feel  the  impression  of 
cold  severely,  and  have  no  resource  but  in  our- 
selves, we  begin  immediately  to  take  exercise, 
and  move  about;  and  if  we  do  this  with  sufficient 
vigour,  the  motions  of  respiration  and  circula- 
tion are  very  soon  increased  in  rate,  and 
our  heat  returns ;  it  being  always  understood 
that  the  external  cold  is  not  at  too  rigorous 
a  degree.  From  what  precedes,  we  are  in  a 
state  to  appreciate  the  part  which  each  func- 
tion has  in  causing  the  developement  of  heat  by 
exercise.  The  experiments  of  Messrs.  Bec- 
querel  and  Breschet,  referred  to  in  an  early 
part  of  this  paper,  have  proved  that  the  con- 
traction of  the  voluntary  muscles  is  accom- 
panied by  the  evolution  of  caloric,  and  that 
the  heat  increases  by  a  succession  of  muscular 
contractions.  The  first  source  of  the  heat 
evolved  in  exercise,  therefore,  lies  in  the  con- 
tractions of  the  muscles,  that  is,  in  the  volun- 
tary motions.  These,  vigorously  called  into 
play,  are  followed  by  increased  rapidity  in  the 
action  of  the  muscles  of  respiration,  and  of 
the  central  muscle  of  circulation,  the  heart ; 
and  these,  by  the  increased  energy  they  impart 
to  the  functions  over  which  they  preside,  cause 
an  increase  in  the  temperature  in  conformity 
with  the  general  principles  already  laid  down. 
It  is  well  to  follow  the  effects  of  exercise  in  the 
various  modifications  under  the  influence  of 
cold.  They  produce  phenomena  which  extend 
farther  than  the  state  of  health,  and  which  ap- 
pear in  other  conditions  and  circumstances 
from  analogous  reasons.  Exercise,  according 
to  its  degree  and  the  degree  of  temperature 
of  the  external  air,  is  adequate  not  only  to 
compensate  a  chill,  and  to  restore  the  body  to 
its  pristine  temperature  in  every  part,  but  even 
to  do  more  than  this.  If  the  exercise  has  been 
sufficiently  prolonged,  but  not  been  excessive, 
it  may  be  suspended  ;  and  the  body,  now  re- 
stored by  its  means  to  its  temperature,  will  be 

2  v  2 


C7G 


ANIMAL  HEAT. 


apt  to  retain  it  longer  than  it  had  clone  when 
exposed  to  cold  without  any  preparation  of  the 
kind  implied  ;  it  will  resist  impressions  of  cold 
longer  after  exercise  than  it  would  after  a  state 
of  perfect  quiescence  ;  the  nervous  system 
has  acquired  new  energy ;  the  economy  is  in 
a  condition  to  react  with  greater  effect  than 
when  depending  on  the  process  just  described, 
that,  namely,  which  takes  place  independently 
of  the  agency  of  the  will.  The  repetition  of 
the  effects  that  follow  exercise  taken  at  due  in- 
tervals, hardens  the  frame  to  such  a  degree  that 
the  body  at  length  acquires  the  power,  by 
means  of  the  insensible  and  involuntary  reac- 
tion alone,  to  resist  degrees  of  cold  which  it 
could  not  have  borne  without  the  violent  and 
voluntarily  induced  reaction  of  active  muscular 
exertion. 

The  different  states  of  the  body  in  the  cir- 
cumstances just  referred  to  deserve  special 
attention,  because  they  are  reproduced  in 
others,  where  the  cause  not  being  apparent 
they  seem  to  be  spontaneous,  though  they  are 
in  fact,  as  we  shall  have  occasion  to  see,  under 
the  influence  of  an  analogous  cause.  We  sup- 
pose that  on  the  first  exposure  to  cold  during 
rest,  the  reaction  from  the  afflux  of  blood  to 
the  capillaries  is  slight,  and  that  the  cold  is 
even  sufficiently  intense  to  produce  an  opposite 
effect,  that  is,  paleness  of  the  part  chilled. 
To  this  symptom  of  the  action  of  cold,  shiver- 
ing is  superadded  in  various  degrees  of  inten- 
sity. If  recourse  be  now  had  to  exercise,  this 
state  will  last  for  a  period  long  in  proportion 
to  its  intensity,  until  violent  and  prolonged  mo- 
tion have  restored  the  temperature.  If  the 
exercise  be  continued,  the  heat  increases,  and 
even  rises  above  its  degree  at  starting  ;  in  this 
case  it  first  restores  the  proper  heat  of  the  skin, 
and  then  causes  this  tegument  to  assume  a  red 
colour,  which  may  become  extremely  intense. 
To  this  second  state  succeeds  a  third,  in  which 
the  skin,  which  had  hitherto  been  dry  and  un- 
perspiring,  becomes  soft  and  finally  bedewed 
with  moisture.  Here,  then,  we  have  three 
different  states  induced  under  the  influence  of 
cold  acting  at  first  without  opposition  on  the 
part  of  the  system,  and  then  combated  by 
powerful  and  voluntary  reaction.  First,  we 
have  coldness,  palene?s,and shivering;  secondly, 
heat  and  redness;  thirdly,  moisture  of  the  skin 
and  sweating.  In  making  the  application 
here  of  what  has  been  said  above  upon  the 
repetition  of  these  acts,  we  perceive  that  at  the 
same  degree  of  external  temperature  the  effects 
which  at  first,  and  under  other  circumstances, 
would  follow  the  impression  of  such  a  degree 
of  cold,  may  cease  to  be  felt.  This  happens 
from  the  constitution  having  improved  under 
the  actions  and  their  effects,  which  have  been 
detailed,  and  that  it  is  in  a  state,  with  the 
assistance  of  its  own  inherent  powers  of  insen- 
sible and  involuntary  reaction,  to  resist  refrige- 
ration. But  do  we  not,  when  we  strengthen 
the  constitution  to  such  a  pitch  as  enables  it  to 
resist  an  influence  which  was  a  cause  of  incon- 
venience to  it  previously,  cure  it  of  an  infir- 
mity ?  It  is  obvious  from  what  precedes  that 
the  temperature  of  the  body  may  be  indiffe- 


rently affected,  either  by  a  great  fall  in  that  of 
the  air,  or  by  an  insufficient  production  of  heat. 
The  temperature  of  the  body  tends  to  sink 
equally  when,  producing  a  great  deal  of  heat, 
it  is  exposed  to  severe  cold,  or  when,  producing 
little  heat,  it  is  exposed  to  a  moderate  warmth. 
In  either  case  the  effects  upon  the  economy 
will  be  analogous  without  being  identical.  In 
each  case  there  will  be  a  keen  sense  of  cold 
according  to  the  depression  of  the  external 
temperature  on  the  one  hand,  or  the  slightness 
of  the  evolution  of  heat  on  the  other.  In  the 
latter  case  the  insensible  reaction  will  be  ex- 
tremely limited,  as  well  as  the  voluntary  reac- 
tion, on  account  of  the  deficient  energy.  But 
there  are  still  resources  within  the  economy.  It 
is  then  that  the  involuntary  and  violent  reaction 
of  which  we  have  already  spoken  takes  place. 
The  circulation  and  the  respiration  increase  in 
rapidity  spontaneously.  In  the  case  which  we 
have  just  supposed,  there  will  be  certain  series 
of  phenomena,  analogous  to  those  we  have 
described  as  occurring  in  the  instance  of  a 
strong  individual  exposed  to  the  influence  of 
severe  cold,  who  suffers  from  it  at  first,  and 
subsequently  opposes  and  vanquishes  it  by 
means  of  a  violent  and  voluntarily  superinduced 
reaction.  When  the  faculty  of  engendering 
heat  sinks  to  a  certain  term,  there  will  be  not 
only  a  vivid  sensation  of  cold  even  in  summer, 
but  all  the  other  consequences  of  exposure  to  a 
low  temperature,  such  as  paleness,  shivering, 
&c. ;  by-and-by  the  involuntary  reaction  will 
not  fail  to  take  place;  the  respiration  and 
circulation  are  accelerated,  and  end  by  restoring 
the  temperature,  if  the  lesion  of  the  calorific 
power  have  not  been  too  extensive,  the  skin 
being  first  hot  and  dry,  and  subsequently  hot 
and  moist.  Here,  consequently,  we  have  the 
three  periods  precisely  as  in  the  case  previously 
described  :  1st,  coldness,  pallor,  and  shivering ; 
2d,  acceleration  of  respiration  and  circula- 
tion, accompanied  in  the  second  period  by  dry 
heat,  and  in  the  third  by  sweating.  There  is 
therefore  the  strongest  analogy  in  the  two 
cases.  They  resemble  one  another  in  the  cha- 
racter of  the  phenomena,  and  the  order  of 
their  succession.  This  is  so  obvious  as  merely 
to  require  mention ;  there  can  be  no  occasion 
for  more  particular  illustration.  They  have 
also  the  strictest  relationship  in  their  causes, 
without  these,  however,  being  identical.  In  the 
first  case  the  individual  produces  a  great  deal 
of  heat,  but  he  cannot  engender  enough  by  the 
ordinary  and  insensible  reaction,  in  conse- 
quence of  which  he  has  recourse  to  the  violent 
and  voluntary  reaction,  which  soon  produces 
the  desired  effect.  In  the  second,  the  indivi- 
dual produces  little  heat,  and  the  economy 
may  suffer  from  this  diminution  of  the  calorific 
faculty  to  the  extent  of  finding  itself  incapable  of 
restoring  a  sufficient  degree  of  heat  by  means  of 
a  violent  and  voluntary  reaction.  The  violent 
and  involuntary  reaction  then  succeeds,  and  pro- 
duces all  the  effects  of  that  which  is  put  into 
play  under  the  empire  of  the  will.  Nor  is  the 
resemblance  limited  to  immediate  results.  It 
further  extends  to  the  remote  and  definitive 
effect.    For  in  either  case  the  violent  effort 


ANIMAL  HEAT. 


677 


ceases  after  a  certain  interval  of  variable  extent, 
according    to    various    circumstances;  and 
a  state  of  tranquillity  comes  on  in  which  the 
body  has  recovered  the  faculty  of  engendering 
by  the  ordinary  means  the  quantity  of  heat  ne- 
cessary to  the  comfortable  existence  of  the  in- 
dividual.   After  this  the  repetition  with  greater 
or  less  frequency  of  the  same  acts  ends  by 
restoring  the  calorific  function  to  the  state  in 
which  insensible  reaction  suffices  to  maintain 
it  in  its  sufficiency.    In  the  first  case  it  is  a 
strong  individual  able  to  make  the  voluntary 
and  energetic  efforts  required  to  remedy  the 
inconvenience  he  suffers.    In  the  other  instance 
it  is  an  individual  who  has  not  the  strength 
requisite  to  make  such  efforts.    In  this  case 
nature  supplies  the   deficiency   by  exciting 
directly  the  motions  of  circulation  and  respira- 
tion by  the  painful  impression  of  cold.  Al- 
though the  condition  of  the  first  be  the  state 
of  health,  and  that  of  the  second  properly  a 
morbid  state,   they   nevertheless  have  many 
relations   in   common,    which   differ  princi- 
pally in  degree.    Does  not  the  robust  indivi- 
dual experience  an  inconvenience  for  which  he 
finds  a  remedy  in  violent  and  repeated  efforts  ? 
However  robust  he  may  be  under  ordinary  cir- 
cumstances, in  the  extraordinary  condition  in 
which  he  is  placed  the  usual  vital  processes 
no  longer  suffice  him.    He  must  have  recourse 
to  violent  means  which  disturb  the  economy  ; 
and  by  a  repetition  of  the  same  efforts  at  diffe- 
rent periods,  that  is  to  say,  in  tits  or  paroxysms, 
he  ends  by  so  far  fortifying  hirnelf  as  to  be  able  to 
do  without  them.    Is  not  this  tantamount  to 
remedying  a  relative  infirmity  of  constitution  ? 
Let  its  degree  increase  but  a  little,  and  the 
infirmity  becomes  disease.    This  parallel  is  not 
founded  on  vague  and  superficial  resemblances, 
but  on  determinate  and  fundamental  relations. 
There  is  not  one  essential  point  in  the  compari- 
son which  does  not  rest  on  the  result  of  direct 
experiments,  most  of  which  have  been  quoted 
in  preceding  parts  of  this  article.    What  must 
be  done  to  justify  the  similitude  of  these 
two  stales  ?    With  regard  to  the  state  of  health 
the  connexion  of  phenomena  having  reference 
to  the  hygienic  and  voluntary  reaction  is  well 
known.  With  reference  to  the  relation  between 
the  symptoms  in  the  morbid  state  and  the 
morbid  reaction,  it  remains  to  be  proved  that 
under  circumstances  where  there  is  but  slight 
production  of  heat,  the  feeling  of  cold  may 
induce  acceleration  in  the  respiratory  and  circu- 
latory motions.    Now  it  has  been  established  by 
experiments  already  quoted,  that  there  is  reac- 
tion of  this  precise  kind  in  such  circumstances. 
We  have  seen,  for  instance,  that  when  a  bird, 
naked  or  scantily  covered  with  feathers,  is 
taken  from  the  nest  and  exposed  to  the  air 
even  in  summer,  it  speedily  begins  to  shiver, 
and  to  exhibit  a  reaction  in  accelerated  motions 
of  respiration,  which  is  followed  by,  and  indeed 
implies  increased  rapidity  in  the  motions  of 
the  heart  and  current  of  the  blood.    It  were 
also  proper  to  show  that  the  cold  state  may,  by 
means  of  the  violent  and  involuntary  reaction, 
induce  the  restoration  of  heat.    This  is  also 


susceptible  of  proof  by  means  of  direct  expe- 
riment.   To  this  end  an  individual  (a  young 
bird  from  the  nest)  must  be  chosen  of  such 
an  age  that  the  temperature  will  not  be  apt  to 
fall  too  low  on  exposure  to  the  air.    If  the 
choice  have  been  fortunate,  it  will  be  found  that 
the  temperature  sinks  in  the  first  instance,  and 
then  rises,  so  that  it  may  even  surpass  the  de- 
gree it  showed  at  first,  under  the  influence  of 
the  reaction  occasioned  by  the  acceleration  of 
the   motions  of  respiration  and  circulation. 
The  proof  here  is,  therefore,  extremely  satis- 
factory. A  creature  in  a  state  of  health  is  taken 
and  placed  in  circumstances  in  which  the  same 
essential  symptoms  are  produced  in  the  same 
order  as  in  the  morbid  state  which  we  have 
described.    It  can  scarcely  be  necessary  to  say 
that  the  morbid  state  which  we  have  described 
in  man  is  that  of  simple  intermittent  fever. 
Not  only  in  the  beginning  of  this  disease  is 
there  a  feeling  of  cold,  but  recent  accurate  ob- 
servations have  shown,  by  means  of  the  ther- 
mometer,  that  there  is  actual  refrigeration. 
There  is,  therefore,  lesion  of  the  calorific  func- 
tion in  the  sense  previously  indicated,  that  is, 
there  is  decrease  in  the  power  to  produce  heat. 
Subsequently  the   temperature   rises  whilst 
there  is  still  more  or  less  of  the  sensation  of 
cold  remaining  ;  but  this  only  happens  by  vir- 
tue of  a  general  disposition  of  the  nervous 
system.    The  same  thing,  in  fact,  occurs  in  a 
state  of  perfect  health  ;  when  the  body  has  for 
some  time  been  exposed  to  severe  cold,  the 
sensation  continues  for  a  certain  interval  after 
it  has  been  restored  to  the  normal  temperature. 
It  is  of  little  consequence,  as  regards  the  sub- 
ject which  engages  our  attention,  that  there  are 
some  intermittent  fevers  which  do  not  exhibit 
the  phenomena  of  temperature  that  have  been 
described.    We  are  only  interested  in  proving 
that  some  do  occur  which  present  them  all, — a 
fact  that  has  been  demonstrated  by  the  best 
authorities. 

There  is  consequently  in  these  cases  a  lesion 
of  the  calorific  function,  a  lesion  of  which  the 
essence  consists  in  a  diminution  of  the  faculty 
of  producing  heat.  In  a  constitution  capable  of 
re-acting  by  the  acceleration  of  the  respiration 
and  circulation,  we  may  observe  upon  this  occa- 
sion two  principal  modifications  of  the  morbid 
state,  which  both  depend  on  the  same  cause, 
but  which  differ  in  degree.  The  first  is  that 
described  in  which  the  reaction  suffices  to 
restore  the  calorific  power  to  the  degree  com- 
patible with  health  after  one  or  more  fits  or 
paroxysms.  With  regard  to  the  second,  the 
diminution  of  the  function  of  calorification  may 
be  so  great,  that  the  reaction  may  prove  in- 
adequate to  restore  it,  not  only  permanently 
but  even  momentarily.  Theie  are  in  fact 
diseases  of  this  kind  ;  there  are  many  regular 
intermittent  fevers  that  have  no  tendency  to 
spontaneous  cure  ;  there  is  also  one  particular 
form  of  the  disease  which  proves  speedily  fatal 
without  the  intervention  of  art.  This  is  that 
form  of  intermittent  which  is  known  at  Rome 
especially  under  the  name  of  ihej'cbbrc  qlgidq, 
or  cold  fever.  It  often  happens  that  the  patient, 


678 


ANIMAL  HEAT. 


unless  suitably  treated,  dies  in  the  cold  stage  of 
the  second  or  third  paroxysm ;  sometimes  he 
will  even  perish  in  the  first. 

It  is  easy  to  produce  at  will  the  essential 
symptoms  of  these  affections  even  in  their  most 
formidable  shapes,  in  animals  in  a  state  of 
health.  All  the  young  birds,  for  example, 
belonging  to  the  group  of  those  which  at  their 
birth  have  the  weaker  calorific  powers,  can  be 
made  to  exhibit  the  phenomena  in  question.  If, 
at  the  period  of  their  exclusion  or  shortly  after 
this,  they  be  taken  out  of  the  nest,  we  have 
seen  that  they  lose  heat  rapidly  even  in  the 
summer  season ;  and  we  perceive  that  any 
reaction  of  which  they  are  capable  by  the 
acceleration  of  their  respiratory  and  circulatory 
motions  avails  them  nothing ;  their  tempera- 
ture sinks  in  spite  of  this,  till  all  reaction 
ceases  by  the  increasing  and  now  benumbing 
influence  of  the  cold,  so  that  they  speedily 
perish.  In  these  two  extreme  cases  of  dimin- 
ished production  of  heat,  there  is  similarity  in 
the  symptoms  which  ensue,  with  this  difference, 
that  in  the  algid  intermittent  there  is  lesion  or  a 
morbid  state  of  the  calorific  faculty;  whilst  in 
the  other  case  the  scanty  production  of  heat  is 
a  normal  condition  in  relation  with  the  age  of 
the  subject.  In  the  first,  the  constitution  is 
seriously  altered  ;  it  must  be  restored  or  other- 
wise the  individual  dies;  in  the  second,  there 
is  no  alteration  of  any  kind ;  the  individual 
only  requires  to  be  placed  in  circumstances 
favourable  to  the  normal  manifestation  of  the 
function  to  be  restored.  In  the  one  the 
lesion  is  so  great  that  there  is  no  resource  in 
nature  abandoned  to  her  own  efforts ;  art  must 
interfere.  In  the  other,  nature  provides  against 
the  scanty  production  of  caloric  in  giving  to 
parents  the  instinct  to  warm  their  young  by  the 
heat  of  their  own  bodies,  &c. 

We  have  seen  that  cold,  when  not  of  too 
great  intensity,  tended  to  strengthen  the  body 
by  increasing  the  faculty  of  producing  heat ; 
and  farther,  that  with  the  progressive  rise  of 
the  temperature  in  spring  and  summer  the 
energy  of  this  faculty  diminished.  This  is 
what  takes  place  with  regard  to  those  constitu- 
tions that  are  in  the  most  favourable  relation 
with  the  climate.  Let  us  now  examine  the 
nature  of  those  constitutions  that  do  not  adapt 
themselves  thoroughly  to  the  changes  of  the 
seasons,  and  see  what  the  consequences  are  with 
regard  to  them.  Let  us  begin  with  the  rela- 
tion of  these  to  the  cold  season  of  the  year. 
It  might  be  presumed  a  priori  that  those  con- 
stitutions that  have  a  very  limited  capacity  of 
engendering  heat  will  not  accommodate  them- 
selves well  to  the  cold  of  winter.  Their 
limited  powers  of  producing  heat  will  not  ena- 
ble them  to  repair  the  continually  increasing 
loss  of  it  arising  from  the  depression  of  the 
external  temperature.  They  consequently  suffer 
in  a  greater  or  less  degree  from  cold,  perhaps 
not  to  any  great  extent  in  the  first  instance, 
as  we  shall  have  occasion  to  explain  by-and- 
by,  but  still  in  some  measure ;  and  there  are 
certain  degrees  of  uneasiness  and  inconvenience 
that  may  be  regarded  as  being  still  within  the 


limits  of  health.  There  is  even  a  certain,  and 
that  a  pretty  wide  latitude  in  which  the  body 
may  vary  without  trespassing  on  the  line  of 
disease.  The  uneasiness  may  only  be  ex- 
perienced from  time  to  time,  and  not  even  be 
always  very  manifestly  referable  to  its  proper 
cause.  In  other  words  the  sensation  may  be 
something  quite  different  from  that  ordinarily 
induced  by  cold;  just  as  it  sometimes  happens 
that  among  weak  constitutions  the  necessity  of 
taking  food  is  not  always  proclaimed  by  the 
feeling  of  hunger,  but  occasionally  by  some 
other  distressing  or  painful  sensation,  with  re- 
gard to  the  true  nature  of  which  experience 
alone  can  enlighten  us.  In  such  a  low  state  of 
the  calorific  power,  the  faculty  seems  to  lose 
strength  still  further,  owing  to  the  simple  per- 
sistence of  the  same  degree  of  cold,  and  still 
more  from  the  ulterior  depression  of  the  tem- 
perature, in  the  manner  we  have  seen  when 
speaking  of  hybernating  animals.  This  dimi- 
nution in  the  temperature  of  the  air  sometimes 
occasions  among  weakly  subjects  morbid  re- 
action, the  principal  features  of  which  have 
already  been  explained.  From  all  that  pre- 
cedes, the  constitutions  that  will  be  the  most  apt 
to  suffer  from  exposure  to  cold  will  be  those  of 
the  earliest  times  of  life  observed  in  man  and 
the  warm  blooded  tribes  generally,  since  it  is 
at  this  epoch  that  they  produce  the  least  heat; 
and  as  a  corollary  from  this,  we  should  infer 
that  the  mortality  in  early  life  ought  to  be 
greater  during  the  winter  season  in  this  and 
other  countries  similarly  circumstanced.  It 
became  a  matter  of  peculiar  interest  to  verify 
this  inference  from  the  experiments  and 
reasonings  of  which  we  have  just  rendered  an 
account.  Messrs.  Villerme  and  Milne  Edwards 
accordingly  undertook  the  necessary  inquiries, 
entering  upon  extensive  statistical  researches 
with  reference  to  the  mortality  of  children  in 
the  different  seasons  of  the  year  in  France,  and 
found  that  the  mortality  of  infants  from  their  birth 
to  the  age  of  three  months  was  generally  the 
greatest  in  those  departments  of  which  the 
winters  were  the  most  severe.  For  a  similar 
reason,  the  natives  of  very  warm  climates  who 
visit  countries  whose  winters  are  excessively 
cold,  run  great  risks  of  not  being  able  to  pro- 
duce heat  enough  to  compensate  the  loss  they 
sustain  from  exposure  to  the  low  atmospheric 
changes,  and  thus  of  becoming  obnoxious  to 
disease  and  death  in  consequence.  Those  that 
have  elasticity  enough  of  c6nstitution  to  meet 
this  unwonted  demand  upon  their  calorific 
powers,  experience  an  increase  in  the  energy  of 
the  functions  upon  which  the  production  of  heat 
depends,  by  which  they  are  brought  into  har- 
mony with  the  climate.  Others  who  are  less 
robustly  constituted  complain  loudly  of  the 
cold,  languish,  and  finally  perish  if  they  do  not 
find  means  of  escaping  from  the  destructive 
tendency  of  the  cold. 

What  happens,  in  as  far  as  these  different  con- 
stitutions are  concerned,  when  the  change  of 
season  is  the  opposite  of  that  we  have  just  dis- 
cussed ?  when  the  progress  is  from  the  colder 
to  the  hotter  period  of  the  year  ?   The  constitu- 


ANIMAL  HEAT. 


679 


lions  that  have  just  been  particularly  mentioned, 
it  is  obvious,  will  find  themselves  benefited  by 
the  change  ;  they  are  continually  supplied  with 
larger  proportions  of  heat  of  which  they  were 
especially  in  want.  But  robust  constitutions, 
in  which  the  calorific  faculty  is  largely  deve- 
loped, will  they  not  be  in  an  opposite  position, 
unless  the  energy  of  the  faculty  in  question 
diminishes  in  proportion  as  the  external  tem- 
perature increases?  This  in  fact  is  what  of 
necessity  happens  to  those  in  whom  the 
power  of  accommodation  is  defective.  For 
when  the  calorific  faculty  continues  in  full 
force,  when  the  temperature  of  the  surrounding- 
atmosphere  is  high,  there  is  an  excess  of  heat 
proceeding  from  within  as  well  as  from 
without ;  and  if  the  body  does  not  suffer  in  the 
first  instance,  which  it  is  apt  to  do,  it  before 
long  feels  the  deteriorating  influence  of  this 
additional  excitement,  which  thensuperinduces 
a  series  of  morbid  phenomena  of  various  degrees 
of  intensity  according  to  circumstances.  All 
this  is  observed  to  occur  in  the  most  distinct 
manner  among  the  natives  of  cold  climates 
who  come  to  reside  in  very  hot  countries.  The 
most  robust  are  even  observed  to  be  the  most 
apt  to  suffer  from  the  change,  and  the  effect  is 
so  decided,  that  few  escape  some  derangement 
of  health,  occasioned  solely  by  the  influence  of 
the  high  temperature.  When  the  affection 
appears  in  the  acute  form,  after  recovery, 
the  new  comer  is  said  to  be  seasoned.  The 
constitution  appears  to  have  suffered  a  favour- 
able change,  which  consists  essentially  in 
a  decrease  of  the  faculty  to  produce  heat.  In 
fact  it  is  often  only  by  a  process  of  this  kind 
that  the  calorific  power  can  be  brought  into 
harmony  with  the  new  circumstances  in  which 
it  is  placed. 

Something  of  the  same  kind  even  takes 
place  in  the  constitutions  of  the  inhabitants  of 
the  countries  which  have  two  very  different 
temperatures  during  the  two  halves  of  the  year. 
Here,  however,  the  change  of  constitution  ge- 
nerally passes  insensibly  or  nearly  so,  the 
transition  being  both  less  in  itself,  and  the 
natives  being  accustomed  to  the  difference. 
Let  us  just  remark  that  we  have  here  another 
instance  of  the  vis  medkutriv  natura,  the  ten- 
dency of  which  at  all  events  is  salutary,  but  of 
which  the  violence  of  effect  by  exceeding  the 
proper  limit  frequently  becomes  fatal.  We 
even  perceive  here  that  nature  has  two  pro- 
cesses at  her  command,  by  which  she  adapts  us 
to  changes  of  external  circumstances  ;  the  one 
is  gradual  and  insensible,  the  other  is  sudden 
and  violent. 

From  repeated  observation,  and  from  experi- 
ments upon  the  effects  of  exposure  to  high  tem- 
peratures, it  is  easy  to  infer  the  general  charac- 
ter of  the  disease  in  its  simplest  form,  which  the 
natives  of  cold  climates  will  be  likely  to  con- 
tract in  hot  countries.  As  a  high  temperature 
of  the  air  accelerates  the  breathing  and  excites 
the  circulation,  it  may  arouse  these  functions  to 
such  a  pitch,  that  the  condition  becomes  truly 
pathological,  and  the  disease  which  results  is 
continued  fever  with  excessive  heat  of  surface  in 


those  countries  where  the  external  conditions 
are  subject  to  little  variety. 

There  are  other  phenomena  accompanying 
changes  of  climate  that  are  referable  rather  to  the 
state  of  health  than  to  any  morbid  condition  that 
bears  upon  the  sensations.  It  is  a  general  re- 
mark that  natives  of  the  warmer  regions  of  the 
earth,  of  a  good  natural  constitution,  when  they 
visit  countries  within  the  temperate  zone,  suffer 
little  from  the  effects  of  cold  the  first  winter ; 
on  the  contrary,  they  seem  to  live  very  much  at 
their  ease,  except  in  extreme  cases.  Let  us  see 
if  we  can  explain  this  fact  with  the  assistance 
of  the  principles  established  above.  If  the 
natives  of  warmer  climates  come  during  the 
summer  to  temperate  countries,  they  experience 
a  change  of  no  great  amount  indeed,  and 
which,  in  the  generality  of  cases,  is  not  obvious. 
The  heat  grows  less  and  less  intense,  declining 
gradually ;  freshness  or  coolness  succeeds ;  then 
comes  moderate,  and  at  last  severe  cold.  Well- 
constituted  individuals,  therefore,  and  they 
may  be  assumed  as  the  majority,  will  experi- 
ence the  general  influence  of  a  gradual  cooling 
process;  that  is  to  say,  their  faculty  of  produ- 
cing heat  will  increase,  whence  will  result  a 
feeling  of  warmth  and  of  comfort.  But  this 
faculty  has  its  limits  of  increase,  which  in  fact 
lie  within  narrower  bounds  than  in  the  case  of 
well-constituted  natives  of  temperate  climates. 
They  are  consequently  apt  at  length  to  fall 
short  of  the  mark,  and  so  to  remain,  in  regard 
to  calorification,  under  the  standard  necessary 
to  the  economy.  Whenever  the  progression 
of  which  we  have  spoken  ceases,  which  hap- 
pens in  the  course  of  the  second  winter,  these 
individuals  begin  to  experience  tiie  uneasiness 
which  results  from  its  deficiency.  It  is  easy  to 
confirm  and  render  manifest  the  justice  of  the 
above  deduction  by  means  of  a  simple  yet 
curious  experiment.  If  a  person  having  warm 
hands  will  keep  one  plunged  for  some  time  in 
water  near  the  freezing  point,  it  becomes  chilled 
of  course,  but  reaction  will  be  observed  soon  to 
take  place,  and  the  hand  will  become  red.  If  it 
be  now  taken  out  of  the  water  and  wiped  dry, 
the  individual  being  all  the  while  in  a  cool  at- 
mosphere, at  10° or  12°  c,  the  hand  will  by-and- 
by  begin  to  glow,  and  the  feeling  in  it  will  be 
that  of  a  temperature  considerably  above  the 
heat  of  the  other  hand  ; — judging  by  the  feeling 
alone  the  hand  seems  hotter  than  the  other;  tried 
by  the  thermometer,  however,  it  will  be  found, 
to  be  cooler;  or  if  it  be  applied  to  the  other,  it 
will  at  once  be  discovered  to  be  below  the  tem- 
perature of  the  hand  that  was  not  chilled. 

Let  us  follow  the  effects  upon  common  sen- 
sation produced  by  a  change  of  climate  of  an 
opposite  kind.  When  the  inhabitants  of  cold 
countries  visit  the  hotter  regions  of  the  globe, 
how  do  they  contrive  to  endure  the  heat  in  the 
first  instance?  Experience  has  often  shown  that 
when  they  are  of  the  same  race,  they  endure  it 
at  first  with  even  greater  ease  than  the  natives 
themselves,  and  that  they  brave  with  greater 
hardihood  and  less  suffering  the  utmost  ardour 
of  the  sun.  This  capacity  of  resistance,  how- 
ever, has  its  term,  and  those  who  possess  it 


680 


ANIMAL  HEAT. 


gradually  lose  it,  as  has  been  shown  in  a 
former  passage  of  this  article.  The  native  of 
the  colder  clime  is  more  robust,  and  his  nervous 
system,  less  impressible,  resists  painful  sensa- 
tions in  a  greater  degree,  and  is  not  over- 
whelmed by  the  first  effects  of  noxious  influ- 
ences. This  conclusion  is  also  susceptible  of 
demonstration  by  the  way  of  direct  experiment. 
If  during  summer  a  frog  be  completely  im- 
mersed in  a  small  quantity  of  water  at  the  ordi- 
nary temperature  of  this  season  of  the  year, 
and  the  same  experiment  be  repeated  during 
winter  with  water  heated  to  the  summer  pitch, 
the  animal  will  live  much  longer  in  the  latter 
than  in  the  former  instance.  The  nervous  sys- 
tem of  the  animal,  by  the  continued  action  of 
the  cold  of  the  autumn  and  winter,  has  been 
rendered  much  more  capable  of  resisting  noxi- 
ous influences,  as  we  have  had  occasion  to  see 
already.  It  is  on  the  same  principle  that  the 
Finlander,  according  to  the  account  of  Acerbi, 
can  endure  a  bath  at  a  much  higher  tempera- 
ture than  it  could  be  borne  by  a  native  of  a 
warm  or  more  temperate  climate. 

EFFECTS  OF  VARIOUS  OTHER  CAUSES  OF  MODI- 
FICATION IN  EXTERNAL  AGENTS. 

The  effects  of  external  heat  and  cold  on  the 
sensations  and  on  the  system  in  general  are  not 
altogether  dependent  on  degrees  of  temperature. 
Even  at  the  same  degree  atmospheric  effects 
are  often  very  different,  being  principally  influ- 
enced by  the  state  of  dryness  or  moisture,  and 
by  that  of  motion  or  rest,  of  the  air.  Speaking 
generally,  media  exert  modifying  influences 
other  than  those  comprised  in  their  tempera- 
ture upon  the  phenomena  of  animal  heat.  Eva- 
poration is  a  powerful  cause  of  cooling,  which 
increases  in  the  same  measure  as  the  evapora- 
tion. In  the  summer  season,  consequently, 
during  a  state  of  the  weather  in  which  the 
temperature  is  the  same,  but  the  hygrome- 
tric  condition  different,  the  heat  of  the  body 
will  be  higher  in  moist  than  in  dry  air.  In  the 
same  way  we  observe  all  the  effects  of  excessive 
temperature  upon  the  body  to  be  much  more 
intense  with  a  moist  than  with  a  dry  atmo- 
sphere. Intheclimate  of  northern  France  orEng- 
land  it  would  be  impossible  to  stand  a  vapour- 
bath  at  a  temperature  between  40°  and  50°  c. 
(104°  to  122°  F.)  for  more  than  ten  or  twelve 
minutes  ;  but  with  a  perfectly  dry  state  of  the 
air  it  is  possible  to  bear  a  temperature  twice,  or 
more  than  twice  as  high  during  the  same  space 
of  time.  M.  Delaroche  found  that  he  could 
not  remain  in  a  vapour-bath  raised  in  the 
course  of  eight  minutes  from  37°,5  to  5  1°,25  c. 
(100°  to  125°  F.)  for  more  than  ten  minutes 
and  a  half,  although  the  bath  fell  one  degree. 
M.  Berger  was  compelled  to  make  his  escape 
within  twelve  minutes  and  a  half  from  a  vapour- 
bath  the  temperature  of  which  had  risen  ra- 
pidly from  4 1°,25  to  53°,75c.  (106°tol29°F.). 
Both  of  these  experimenters  felt  themselves 
become  weak  and  unstable  on  their  legs,  and 
were  affected  with  vertigo,  thirst,  &c.  The 
weakness  and  thirst  continued  through  the 
remainder  of  the  day.    But  in  the  course  of 


Dr.  Dobson's  experiments,  a  young  man  con- 
tinued for  twenty  minutes  in  a  dry-air  stove, 
the  temperature  of  which  was  98°,88  c. 
(210°  F.),  within  a  degree  or  two,  conse- 
quently, of  the  ordinary  boiling  temperature 
of  water.  His  pulse,  which  usually  beat  75 
times  in  a  minute,  now  beat  164  times. 
This,  however,  is  by  no  means  the  degree 
of  heat  that  can  be  and  that  has  been  en- 
dured. M.  Berger  for  five  minutes  bore  a 
temperature  of  109°,48c;  and  Sir  Charles 
Blagden  went  still  further,  having  exposed  his 
body  during  eight  minutes  to  the  contact  of 
dry  air  heated  up  to  the  extraordinary  pitch 
of  115°,55  and  127°,7c.  (240°  and  260°  F.). 
In  assigning  40°  or  50°  c.  (104°  or  122°  F.) 
for  the  limits  of  moist  temperature  that  can 
be  borne  by  the  inhabitants  of  these  coun- 
tries, we  are  perfectly  aware  that  in  other  lati- 
tudes it  can  be  greatly  exceeded.  Thus  Acerbi, 
in  his  journey  to  the  North  Cape,  informs  us 
that  the  Finnish  peasantry  remain  for  half  an 
hour  or  more  in  a  vapour-bath,  the  temperature 
of  which  finally  rises  to  70°  and  even  75°  c. 
(158°  and  167°  F.).  We  have  already  given 
the  reason  of  this  difference  of  constitution. 

Experimental  philosophers  have  not  yet  tried 
the  precise  comparative  cooling  effects  of  dry 
air  and  of  watery  vapour ;  but  all  are  agreed 
that  the  powers  of  the  moist  atmosphere  are  by 
far  the  most  considerable.  To  measure  the 
comparative  effects  upon  the  economy  the  fol- 
lowing experiments  were  instituted.  In  equal 
spaces,  the  one  filled  with  air  at  the  point  of 
extreme  humidity,  the  other  with  extremely  dry 
air,  were  placed  young  birds  of  the  same  age, 
which  were  as  yet  incapable  of  maintaining 
their  temperature  at  its  proper  height  when 
taken  out  of  the  nest.  It  was  found  that  they 
lost  temperature  nearly  in  the  same  propor- 
tion in  the  same  space  of  time  when  the  air 
was  either  at  the  point  of  extreme  humidity 
or  of  great  dryness.  Therefore  moist  air  tends 
to  cool  at  least  as  much  as  dry  air  by  evapora- 
tion. It  cools  both  by  the  abstraction  of  heat 
and  by  its  action  on  the  nervous  system.  Its 
action  on  the  nervous  system  is  of  a  debilitating 
nature,  and  therefore  tends  to  diminish  the 
power  of  generating  heat.  The  sensation  of 
cold  was  evidently  greater  in  the  moist  air,  as 
was  shown  by  the  shivering  of  the  animal. 
There  can  be  no  doubt  that  the  action  of 
vapour  in  this  case  is  complicated  by  a  physi- 
cal influence  in  the  one  instance,  and  by  a  pecu- 
liar physiological  effect  on  the  nervous  system 
in  the  other  ;  for  it  is  well  ascertained  that  water, 
as  contrasted  with  air,  has  a  debilitating  effect 
upon  the  economy.  General  experience  comes 
in  support  of  these  results ;  men  have  ever 
agreed  that  moist  and  cold  states  of  the  atmo- 
sphere and  humid  and  cold  climates  were  more 
difficult  to  be  borne  than  those  of  an  opposite 
character.  Such  climes  in  fact  are  in  them- 
selves extremely  insalubrious.  By  their  pecu- 
liar effects  on  the  economy  they  tend  greatly  to 
lessen  the  power  of  producing  heat,  and  they 
also  engender  intermittent  fevers,  among  other 
morbid  conditions.    According  to  the  state  of 


ANIMAL  HEAT. 


681 


the  economy  and  the  degree  of  the  external 
temperature,  watery  vapour  tends  to  refrigerate 
still  more  in  winter,  and  to  add  to  the  heat  in 
summer. 

The  state  of  the  atmosphere  in  regard  to 
motion  or  rest  modifies  to  a  great  extent  the 
effects  of  a  given  temperature  upon  the  body. 
Refrigeration  by  simple  contact  increases  in 
amount  with  the  rate  of  motion  of  the  air.  The 
same  law  holds  good  in  regard  to  evaporation, 
and  indeed  this  process  always  complicates  the 
results  proceeding  from  simple  contact.  The 
cause  of  refrigeration  in  this  case  is  consequently 
double.  It  is  easy,  therefore,  to  imagine  how 
powerful  a  cause  of  cooling  a  cold  wind  must 
be.  But  observation  can  alone  give  any  ade- 
quate idea  of  the  extent  of  its  influence  in  this 
respect.  Mr.  Fisher,  one  of  the  surgeons  in 
the  expedition  under  the  command  of  Sir 
Edward  Parry  to  the  Polar  Seas,  has  given  us 
an  account  of  its  extraordinary  effects.  In  the 
frozen  regions  around  the  arctic  circle,  the 
hardy  voyagers  under  Capt.  Sir  E.  Parry  found 
that  they  could  stand  a  cold  adequate  to  freeze 
mercury  when  the  air  was  perfectly  calm,  much 
more  easily  than  a  temperature  nearly  50°  F. 
higher  when  it  blew.  The  air  in  motion  in 
this  case,  therefore,  produced  a  sensation  of 
cold  that  was  equal  to  such  a  depression  of 
temperature  as  is  indicated  by  a  fall  of  50°  of 
the  scale  of  F. — a  most  prodigious  difference. 

Sudden  transitions  of  temperature  also  exert 
a  great  influence  independently  of  any  limits  ; 
in  the  first  place,  because  the  intenseness  of 
the  sensation  of  cold  or  of  heat  is  in  propor- 
tion to  the  suddenness  of  the  abstraction,  or  of 
the  communication  of  heat ;  and  again,  be- 
cause the  faculty  of  adaptation  to  different 
degrees  of  external  temperature  is  not  acquired 
all  at  once,  but  is  only  attained  in  a  certain 
lapse  of  time,  and  by  gradual  modifications 
in  the  constitution.  We  therefore  see  that 
those  countries  of  which  the  temperature  is 
very  high  in  the  day,  but  very  low  in  the  night, 
are  subject  to  diseases  that  seem  to  belong 
more  peculiarly  to  cold  and  moist  latitudes, 
or  to  marshy  lands  where  malaria  prevails. 
But  the  transition  from  hot  to  cold  is  not 
limited  to  the  suddenness  of  the  thermal  de- 
pression ;  it  extends  to  the  refrigeration  by  the 
action  of  the  wind.  This  is  another  among 
the  many  reasons  why  in  the  latitudes  of  Eng- 
land, France,  &c.  spring  is  a  more  dangerous 
season  than  autumn.  There  are,  however,  cer- 
tain cases  of  sudden  transition  that  are  useful 
and  salutary,  as  forinstance,when  the  heat  of  the 
body  is  excessive,  and  is  doing  mischief,  whe- 
ther it  be  induced  by  an  elevated  external 
temperature,  or  proceeds  from  the  violent  and 
involuntary  action  of  our  organs.  Then  re- 
frigeration even  of  the  most  sudden  kind,  pro- 
vided it  be  restrained  within  proper  limits, 
becomes  beneficial.  It  is  thus  that  the 
affusion  of  cold  water  produces  such  excellent 
effects  in  cases  of  extreme  excitement,  and 
where  the  temperature  is  really  above  the 
natural  standard.  This  process  is  even  to  be 
regarded  as  one  of  the  most  brilliant  tri- 
umphs of  modern  medicine.    It  is  much  to 


be  regretted  that  recourse  is  not  had  to  it  more 
frequently.  It  is  evident  that  the  proper  time 
for  the  use  of  this  powerful  means  is  that  in 
which  congestion  has  not  yet  passed  into  ob- 
stinate engorgement,  that  is  to  say,  in  the 
beginning  of  the  disease,  in  which  by  allaying 
excitement  congestion  is  diminished.  The 
favourable  moment  for  using  the  cold  affusion  is 
that  in  which  the  skm  is  hot  and  dry,  which 
is  also  the  period  of  the  highest  excitation. 
The  experiments  upon  the  effects  of  baths, 
quoted  above,  tend  also  to  show  the  propriety  of 
the  practice  ;  in  citing  these,  we  mentioned  that 
the  diminution  of  temperature  produced  in  the 
body  lasted  for  hours,  and  that  the  reaction 
consequent  upon  the  use  of  the  bath  did  not 
carry  the  temperature  higher  than  the  pitch  it 
possessed  at  starting.  It  is  obvious  that  the 
effects  of  the  cold  affusion  are  to  be  derived 
from  the  principles  previously  established ; 
since  we  have  referred  the  production  of  heat 
to  two  general  conditions  of  the  economy, 
one  of  which  is  the  state  of  the  nervous  sys- 
tem. Now  the  affusion  of  cold  water  acts 
directly  upon  this  system.  There  is  another 
powerful  method  of  tempering  animal  heat, 
which  flows  from  the  other  general  condition, 
upon  which  the  production  of  heat  depends, 
viz.  the  state  of  the  blood.  We  have  seen 
above  that  the  respective  proportions  of  the 
serous  mass  of  the  blood  and  of  its  red  glo- 
bules exert  an  important  influence;  that  in 
the  class  of  vertebrate  animals  which  produce 
smaller  quantities  of  heat,  the  proportion  of 
the  serum  was  in  the  inverse  ratio  of  the 
faculty  of  calorification.  Whence  it  follows, 
that  in  cases  of  excessive  heat  of  body,  to 
reduce  the  quantity  of  red  globules  would 
prove  an  effectual  mode  of  reducing  the  tem- 
perature. Now  this  is  precisely  what  is  done 
by  bloodletting.  The  effect,  however,  in  this 
way  is  not  instantaneous.  The  first  influence 
of  bloodletting  is  simply  to  lessen  the  quan- 
tity of  the  blood,  and  this  is  the  extent  to 
which  ideas  of  the  influence  of  the  abstraction 
of  blood  are  generally  confined.  There  is, 
however,  a  consecutive  influence,  which  is  at 
the  least  as  important,  and  which  proves  much 
more  lasting.  As  the  person  who  has  been  let 
blood  confines  himself  at  the  same  time  to 
low  diet,  and  principally  to  liquids,  it  is  obvious 
that  the  blood  is  recruited  in  its  quantity 
principally  by  additions  of  watery  particles, 
without  any  notable  or  even  sensible  addition 
of  globules.  The  blood  is  therefore  altered 
essentially  in  its  constitution;  the  proportion 
of  its  component  fluid  and  solid  elements  is 
changed,  and  this  in  direct  proportion  to  the 
extent  and  frequency  of  the  venesections.  The 
consequence  of  this  is  a  diminution  of  tempe- 
rature, unless  other  causes  oppose  such  an  ef- 
fect. 

Bloodletting,  it  must  be  observed,  is  not  the 
sole  means  of  accomplishing  such  a  change  in 
the  constitution  of  the  blood.  We  can  pro- 
duce a  similar  effect  by  exciting  one  or  all  of 
the  secretions  which  are  thrown  off  by  the 
body.  Secretion  is  performed  at  the  cost  of 
the  blood,  which  supplies  both  of  its  element? 


682 


ANIMAL  HEAT. 


— the  solid  and  the  fluid  part.  The  more 
the  secretion  eliminated  abounds  in  solid  parts 
or  matters  formed  at  the  cost  of  the  solid 
constituents  of  the  blood,  the  more  is  the 
blood  impoverished  in  these  elements — the 
more  is  its  mass  of  globules  diminished. 
Absorption  then  begins,  as  in  the  preceding 
case,  to  make  up  the  quantity  of  circulating 
fluid ;  and  if  this  faculty  have  only  fluids  to 
work  upon,  it  is  evident  that,  as  in  the  case  of 
bloodletting,  the  blood  will  become  more  serous 
than  before.  The  perspiration  and  the  alvine 
secretions  act  in  this  manner,  and  nature 
makes  use  of  these,  especially  of  the  former, 
to  temper  the  burning  heat  of  paroxysms  of 
fever.  Art  but  imitates  nature  in  the  treat- 
ment of  acute  diseases  ;  she  strives  to  procure 
action  of  the  skin,  and  especially  action  of 
the  bowels.  The  use  of  diaphoretics  and  pur- 
gatives is  therefore  plainly  borne  out  by  the 
principles  which  have  been  laid  down.  The 
alvine  secretions  are  those  especially  that  carry 
off  the  largest  proportion  of  solid  matters  from 
the  blood,  and  which  therefore,  when  excited, 
prove  the  most  permanently  efficient  in  keep- 
ing down  the  temperature  of  the  body.  There 
is  another  important  reason  for  preferring  the 
intestinal  canal  to  the  skin  as  the  means,  in 
the  generality  of  instances,  of  reducing  tem- 
perature in  the  treatment  of  disease,  which 
ought  not  to  be  lost  sight  of :  this  is,  that 
we  can  excite  the  intestinal  evacuations  to  a 
great  extent  without  arousing  the  circulating 
system  in  almost  any  degree ;  very  different 
from  what  occurs  when  we  attempt  to  unload 
the  vessels  by  the  way  of  the  cutaneous  exha- 
lants,  in  which  it  is  generally  impossible  to 
produce  abundant  diaphoresis  without  arous- 
ing the  heart  and  arteries  to  unwonted  action 
as  a  preliminary.  Purgative  medicines,  there- 
fore, next  to  the  direct  abstraction  of  blood, 
are  the  most  potent  means  of  tempering  the 
heat  of  the  body  by  modifying  the  consti- 
tution of  the  blood.  Nothing  that  influences 
the  economy  can  have  an  effect  in  one  direc- 
tion only.  It  were  foreign  to  our  purpose, 
however,  to  enter  upon  any  other  than  that 
which  bears  immediately  upon  our  subject. 

There  is  another  natural  process  analogous 
in  its  effects,  which  the  preceding  consider- 
ations place  in  a  new  point  of  view.  This 
is  the  influence  of  diet  and  regimen.  Low 
diet  does  not  act  merely  in  preventing  the  ex- 
citement which  always  follows  the  ingestion  of 
solid  food ;  it  further  alters  the  constitution  of 
the  blood.  This  fluid,  receiving  a  more  scanty 
supply  of  solid  matters,  continues  nevertheless 
to  supply  the  natural  secretions  as  before,  and 
consequently  very  speedily  undergoes  by  this 
alone  a  diminution  in  the  proportion  of  its 
globules,  in  the  direct  ratio  of  the  duration  of 
the  system  of  spare  diet.  Low  diet  is  there- 
fore a  means  which  acts  in  the  same  way  as 
bloodletting  and  purging,  with  this  difference 
however,  that  it  is  slower  in  its  operation,  and 
in  the  first  instance  less  marked  in  its  effects. 
This,  therefore,  is  the  slowest  and  least  efficaci- 
ous of  the  immediate  means  of  reducing  tem- 
perature when  employed  alone,  although  its 


conjunction  is  indispensable  to  the  success  of 
any  of  the  others. 

Of  all  these  means,  one  only  is  the  proper 
effect  of  art,  namely,  the  application  of  cold  ; 
the  others  are  processes  of  the  same  natura 
medicatriv,  and  processes  which  we  merely 
imitate.  These  act  directly  in  modifying  the 
constitution  of  the  blood,  and  thus  definitively 
influence  the  nervous  system.  The  other 
exerts  its  influence  directly  on  the  nervous 
system,  in  calming  the  excitement  or  violent 
action  which  it  has  engendered  in  the  sangui- 
ferous system,  and  those  that  depend  on  it. 

The  application  of  heat  becomes  necessary 
in  morbid  states  the  reverse  of  those  that 
have  just  been  discussed.  The  proper  employ- 
ment of  this  means  depends  especially  on 
two  general  principles  bearing  upon  animal 
heat,  which  we  have  considered  above.  1st, 
The  one  is,  that  the  economy  has  the  capacity 
of  bearing  heat  in  the  same  proportion  as 
the  function  of  respiration  is  extended.  In 
those  cases  in  which  this  function  is  limited, 
or,  what  comes  to  the  same  thing,  where  any  part 
that  requires  an  accession  of  heat  is  indiffer- 
ently supplied  with  arterial  blood,  it  is  neces- 
sary to  be  extremely  cautious  in  its  applica- 
tion. 2nd,  The  other,  that  the  effects  of  ex- 
ternal heat  are  not  confined  to  the  simple 
interval  during  which  it  is  applied,  but  remain 
after  it  has  been  removed,  and  even  increase 
the  faculty  of  producing  heat.  The  applica- 
tion of  warmth  is  therefore  not  merely  pallia- 
tive or  supplementary  of  lost  heat ;  it  has 
further  a  directly  remedial  influence,  which 
may  even  be  excited  in  excess.  When  the 
lesion  of  the  calorific  faculty  has  been  great, 
without  much  or  any  organic  lesion,  other 
means  of  greater  force  than  those  usually  re- 
sorted to  by  art,  or  employed  by  nature  in 
such  circumstances,  must  be  called  in  to  assist. 
Art  has  happily  discovered  what  seems  the 
most  effectual  means  of  winding  up  the 
nervous  system,  and  enabling  the  calorific 
faculty  to  be  re-established  in  its  normal  con- 
dition. This  means  is  quinia,  the  first  of 
tonics.  This  powerful  medicine  is  conse- 
quently never  administered  in  acute  diseases 
until  all  violence  of  action  has  ceased,  and 
the  functions  have  resumed  their  habitual 
rythm.  We  find  that  the  action  of  this 
medicine  is  exerted  directly  upon  the  nervous 
system  from  this,  that  it  seems  to  have  no 
effect  on  the  secretions,  or  when  it  does  in- 
fluence these,  we  are  convinced  by  the  tri- 
fling amount  of  the  effect,  that  it  is  not  through 
them  that  the  cure  is  accomplished.  As  it 
acts  during  the  intermission,  by  restoring  the 
normal  production  of  heat,  we  have  no  reason 
to  expect  the  phenomena  which  characterize 
the  fit — the  shivering,  &c. ;  and  then  the  vio- 
lent reaction  which  we  have  in  the  hot  stage 
becomes  useless,  and  in  fact  is  no  longer  ob- 
served. 

Confirmation  of  the  general  results. 
We  have  thus  passed  in  review  the  principal 
phenomena  of  animal  heat,  reducing  or  ap- 
proximating these  at  all  times  to  the  most 


ANIMAL  HEAT. 


683 


simple  conditions.     These  conditions  them- 
selves are,  in  the  first  place,  assumed  from 
comparisons  of  the  organization  of  the  two 
grand  groups  or  series  into  which  the  animal 
kingdom  is  divided  with  reference  to  heat— 
the  cold-blooded   animals,  and   the  warm- 
blooded animals.    In   this  review  we  have 
avoided  all  hypothesis,  confining  ourselves  to 
the  severe  method  of  deduction,  always  starting 
from  well-authenticated  facts,  and  even  con- 
firming each  step  in  advance  by  new  data 
equally  indisputable.      The  harmony  which 
reigns   in  this  comprehensive  whole,  which 
embraces  the  different  classes  of  animals  and 
man,  not  only  in  the  various  modifications  of 
health,  but  even  of  disease,  in  their  relation 
to  external  agents,  and  the  therapeutic  pro- 
cesses of  nature  and  of  art,  afford  the  surest 
confirmation  of  the  reality  of  these  relations. 
As  the  phenomena  of  animal  heat  are  re- 
ferable to  two  general  conditions  of  the  eco- 
nomy,— the  state  of  the  blood  and  that  of 
the  nervous  system ;  and  as  we  have  only  in 
the  first  instance  deduced  these  from  the  com- 
parison  of  natural  facts,  although  we  have 
confirmed  them  by  new  observations  and  par- 
ticular experiments,  one  may  be  desirous  of 
seeing  them  confirmed  by  experiments  of  a 
more  general  bearing.    To  the  reasonableness 
of  this  wish  we  yield  assent  the  more  willingly, 
as  the  results  we  have  to  quote  are  deductions 
from  some  of  the  most  admirable  researches 
that  have  been  instituted  by  physiologists ; — 
I  allude  to  the   enquiries  of  Legallois,  Sir 
Benjamin  Brodie,  and  Dr.  Chossat. 

The  first  of  these  experimenters,  by  the  em- 
ployment of  various  means  for  impeding  re- 
spiration, or  limiting  the  consumption  of  air, 
found  that  the  refrigeration  of  animals  is  in 
the  compound  ratio  of  the  difficulty  experienced 
in  breathing  and  of  the  quantity  of  oxygen  con- 
sumed ;  so  that  when,  in  two  experiments,  the 
difficulty  of  breathing  is  the  same,  the  greatest 
extent  of  cooling  occurs  in  that  in  which  the 
smallest  quantity  of  oxygen  is  vitiated,  and  the 
contrary.  Now,  the  end  of  the  process  of 
respiration  being  to  change  the  venous  into 
arterial  blood,  this  conclusion  of  Legallois  con- 
firms directly  the  one  of  the  two  principal 
conditions — the  state  of  the  blood,  which  we 
have  laid  down  as  influencing  the  production 
of  heat  among  animals,  and  to  the  knowledge 
of  which  we  had  attained  by  induction. 

The  results  of  the  direct  experiments  which 
we  have  still  to  quote  also  come  powerfully 
in  aid  of  our  inferences  concerning  the  other 
principal  condition,  which  we  have  assumed 
from  induction,  influencing  the  production  of 
animal  heat:  this  is  the  state  or  action  of 

THE  NERVOUS  SYSTEM. 

Sir  B.  Brodie  demonstrated  by  a  series  of 
the  most  ingeniously  conceived  and  happily 
executed  experiments,  that  when  animals  were 
decapitated  and  respiration  was  kept  up  by 
artificial  means,  so  that  the  blood  circulated 
as  usual,  and  the  process  of  change  from  the 
venous  to  the  arterial  state  went  on  uninter- 
ruptedly, the  ordinary  quantity  of  carbonic 
acid  being  eliminated,  all  the  while,  that,  ne- 


vertheless, the  temperature  fell  rapidly,  even 
more  rapidly  than  when  no  artificial  respiration 
was  maintained. 

Dr.  Chossat  completed  these  researches  upon 
the  nervous  system  in  its  relations  with  the 
production  of  heat,  by  demonstrating  in  a 
series  of  experiments  the  following  very  im- 
portant fact,  viz.  that  the  depression  of  animal 
heat  is  constantly  in  relation  with  lesions  of 
the  nervous  system,  whether  these  lesions  im- 
plicate the  cerebrospinal  system,  or  the  system 
of  the  great  sympathetic. 

We  necessarily  confine  ourselves,  in  alluding 
to  these  admirable  researches,  to  the  most 
general  results,  and  the  conclusions  flowing 
most  immediately  from  the  experiments  insti- 
tuted. We  reserve  a  more  particular  mention 
of  them  for  the  proper  place,  namely,  the 
article  on  Respiration,  to  which  we  beg  to 
refer.  With  regard  to  the  opinions  of  writers 
generally,  we  shall  be  content  to  observe  here, 
that  they  have  for  the  most  part  regarded  the 
single  physiological  condition  which  was  the 
subject  of  their  particular  study  as  the  only 
source  of  animal  heat.  The  general  result  of 
their  united  labours,  however,  is,  that  there 
are  two  principal  sources,  the  one  depending 
on  the  arterial  blood,  the  other  on  the  energy 
of  the  nervous  system, — a  conclusion  to  which 
we  have  come  by  another  way,  by  combining 
all  the  known  facts  that  bear  upon  animal  heat, 
and  embracing  the  manifestations  presented  by 
the  whole  of  the  animal  kingdom  as  well  as 
the  isolated  phenomena  exhibited  by  man,  and 
this  not  in  one  but  in  every  condition  of  ex- 
istence, not  only  in  the  state  of  health  but  of 
disease  likewise,  not  as  beings  independent  of 
all  things  around  them,  but  as  living  in  intimate 
relationship  with  external  agents. 

Of  the  physical  cause  of  animal  heat, 
With  regard  to  the  physical  cause  of  animal 
heat,  or  to  its  mode  of  production,  there  was 
a  time,  which  we  have  not  yet  left  very  far 
behind  us,  when  natural  philosophers  and 
chemists  imagined  they  possessed  the  secret, 
especially  with  reference  to  the  mineral  king- 
dom. They  have  now  discovered  their  mis- 
take ;  and  as  the  evolution  of  heat  is  a  mystery 
to  them,  it  is  not  to  be  expected  that  it  is  less 
so  to  physiologists,  as  manifested  in  the  do- 
main which  they  cultivate  in  peculiar.  The 
problem,  in  fact,  becomes  immensely  com- 
plicated by  a  variety  of  phenomena  when  from 
the  inorganic  we  ascend  to  the  organic  world. 
All  that  could  be  done  has  been  accomplished  ; 
from  the  particular  conditions  of  organization 
and  of  function  upon  which  this  effect 
seemed  to  depend,  physiologists  have  risen  to 
those  that  were  the  most  general  and  com- 
prehensive. This,  in  fact,  was  the  end  we 
proposed  in  commencing  this  article.  That 
nothing  may  be  omitted  which  can  make  the 
sketch  more  complete,  and  none  of  the  great 
inquiries  which  have  had  animal  heat  for  their 
object  may  be  passed  over  in  silence,  we  shall 
briefly  cite  the  more  important  of  those  in 
which  the  mode  of  production  of  animal  heat 
is  discussed,  always  reserving  to  ourselves  the 


684 


HERMAPHRODITISM. 


opportunity  of  treating  several  of  these  more 
fully  in  our  article  on  Respiration. 

Lavoisier,  from  his  labours  on  combustion, 
which  laid  the  foundation  of  the  chemical 
doctrines  of  the  age  that  has  just  elapsed, 
conceived  the  ingenious  idea  of  explaining  the 
phenomena  of  animal  heat  by  the  combustion 
of  the  carbon  and  hydrogen  of  the  blood  by 
the  oxygen  of  the  air  in  the  process  of  respi- 
ration, and  the  experiments  which  he  instituted 
upon  this  point  along  with  the  illustrious  La 
Place  appeared  to  confirm  his  idea.  Still  it 
was  found  impossible  to  give  an  account  of  the 
production  of  the  whole  heat  engendered  by 
animals.  All  that  Lavoisier  and  La  Place  in- 
ferred was,  that  the  heat  evolved  by  an  animal 
was  almost  entirely  produced  by  the  combus- 
tion which  occurs  in  respiration.  As  the  calo- 
rific power  was  measured  in  one  animal,  and 
the  consumption  of  oxygen  in  another,  it  is 
evident  that  the  inference,  vitiated  in  its  ele- 
ments, became  much  less  precise  than  it  would 
otherwise  have  been. 

This  consideration  as  well  as  others  induced 
M.  Dulong,  who  is  as  well  versed  in  mecha- 
nical philosophy  as  in  chemistry,  to  take  up 
this  subject  again.  After  numerous  experi- 
ments, conducted  with  every  precaution  that 
could  secure  accuracy  of  result,  he  found  that 
the  heat  disengaged  by  the  fixation  of  the 
oxygen  in  the  act  of  respiration  was  not  equal 
to  the  whole  of  that  which  was  produced  by 
an  animal.  This  inquiry  (which  however  stood 
in  no  need  of  confirmation)  has  been  con- 
firmed by  the  analogous  inquiries  of  M.  De- 
spretz,  who  arrived  at  the  same  numerical 
results.  The  hypothesis  in  question,  there- 
fore, gives  no  solution  of  the  problem. 

BIBLIOGRAPHY. — Martine,  Essay  on  the  genera- 
tion of  Animal  Heat,  in  Essays  Med.  and  Philos. 
Lond.  1740.  Huller,  De  generat.  caloris,  &c.  Goett. 
1741.    Stevenson,  Essay  on  the  cause  of  Animal 
Heat.&c.  Med.  Essays  and  Obs.  vol.  5.  Mortimer, 
Letter  concerning  the  Nat.  Heat  of  Animals,  Phil. 
Trans.  1745.    Braim,  De  calore  animalium,  Nov. 
Comm.  Petrop.  t.  13.    Duncan,  Hypotheses  of  the 
cause  of  Animal  Heat,  Med.  and  Phil.  Com.  vol. 
6.    Experts.  &c.  Min.  of  Society  for  Philos.  Ex- 
perts, p.  157.    Martin  ( A.R.),  Various  Papers  on 
Animal  Heat  in  the  Svenska  Vetensk.  Akad.  Hand- 
lingar  for  the  years  1764  and  1766.    Hunter,  Ex- 
perts, on  the  power  of  producing  Heat,  and  on  the 
Heat  of  Vegetables  and  Animals,  Phil.  Trans.  1775- 
1778,  and  in  Animal  Economy.  Crawford( D.J. M.J, 
De  Calore  Animali,  Edinb.    Exprts.  and  Obs.  on 
Animal  Heat,  Phil.  Trans.  1786,  separately,  2d  ed. 
1788.    Leslie,  Philos.  Inquiry  into  Animal  Heat, 
Lond.  1778.    Rigby,  Essay  on  the  Theory  of  the 
Prod,  of  Animal  Heat,  Lond.  1785.    Delaroche  et 
Berger,  Mcmoire,  &c.  in  Journ.  de  Physique,  t.  71. 
Brodie,  in  Croonian  Lecture,  Phil.  Trans.  1811. 
Davy,  An  Acc.  of  some  Experts,  on  Animal  Heat, 
Phil.  Trans.  1814.  '  Legallois,  Mem.  sur  la  chaleur 
animale,  Ann.  de  Chimie,  t.  iv.   Earle,  Influence  of 
the  nervous  system  in  regulating  Heat,  Med.  Chir. 
Trans,  vol.  vii.     Chossat,  Influence  du  Systeme 
Nerveux  sur  la  Chaleur  Animale,  These,  Paris,  1820. 
Dulong,  De  la  Chaleur  Animale,  Journ.  de  Physiol, 
t.  3.  Despretx  ( Rich.),  Exper.  sur  la  Chaleur  Anim. 
Ann.  de  Chimie,  t.  26.    Home,  Influence  of  the 
Nerves  in  prodticing  Animal  Heat,  Phil.  Trans,  v. 
115.    Collard  de  Martigny,De  l'Influence  de  la  Cir- 
culation, &c.  sur  la  Chaleur  du  Sang,  Journ.  Com- 
plem.  t.  xliii.    Vide  also  Journ,  Complem.  t.  xxvi. 


The  general  works  on  Physiology,  particularly 
those  of  Rudolphi  and  Tiedemann.  Czermack,  On 
the  Temperature  of  Reptiles,  in  Zeitschr.  fiir  Phy- 
sik,  &c.  Bd.3.  Berthold,  Neue  versuche  uber  die 
Temperature,  &c.  Gotting.  1835.  Transl.  in  Ann. 
d'Analomie,  &c.  Mai  1838.  Newport,  Temp,  of 
Insects,  Phil.  Trans.  1837.  Becquerel  Breschet, 
Mem.  surla  Chaleur  Animale,  in  Ann.  des  Sciences, 
Nat.  Seconde  Serie,  t.  3,  4,  &  9. 

(  W.  F.  Edivards.) 

HERMAPHRODITISM,  or  Hermaphro- 

dism;*  Hermaphrodisia ;  androgynisme,  gynan- 
drisme ;  hermaphroditisme,  &c,  of  the  French  ; 
ermaphrodismo  of  the  Italians ;  Zwitterbildung 
of  the  Germans,  &c. 

Many  different  definitions  of  hermaphro- 
ditism, and  almost  an  equal  number  of  diffe- 
rent classifications  of  the  malformations  usu- 
ally comprehended  under  it,  have  been  proposed 
by  the  various  authors,  ancient  and  modern, 
who  have  directed  their  attention  to  this  sub- 
ject. Without  stopping  to  discuss  the  merits 
or  errors  of  these  definitions  and  classifications, 
and  without  inquiring,  as  some  have  done, 
into  the  propriety  of  the  word  itself,  we  shall 
content  ourselves  with  stating  that  under  it,  as 
a  convenient  generic  term,  we  purpose  in  the 
present  article  to  include  an  account — 1st,  of 
some  varieties  of  malformation  in  which  the 
genital  organs  and  general  sexual  configura- 
tion of  one  sex  approach,  from  imperfect  or  ab- 
normal developement,  to  those  of  the  opposite  ; 
and  2d,  of  other  varieties  of  malformation,  in 
which  there  actually  coexist  upon  the  body  of 
the  same  individual  more  or  fewer  of  the  geni- 
tal organs  and  distinctive  sexual  characters 
both  of  the  male  and  female. 

To  separate  from  one  another,  by  as  strong  a 
line  as  possible,  the  two  distinct  varieties  of 
hermaphroditic  malformation  marked  out  in 
this  definition,  we  shall  divide  hermaphroditic 
malformations,  considered  as  a  class,  into  the 
two  orders  of  Spurious  and  True;  the  spurious 
comprehending  such  malformations  of  the 
genital  organs  of  one  sex  as  make  these  organs 
approximate  in  appearance  and  form  to  those 
of  the  opposite  sexual  type ;  and  the  order, 
again,  of  true  hermaphroditism  including 
under  it  all  cases  in  which  there  is  an  actual 
mixture  or  blending  together,  upon  the  same 
individual,  of  more  or  fewer  of  both  the  male 
and  female  organs. 

Spurious  hermaphroditism  may  occur  either 
in  the  male  or  female ;  that  is,  there  may,  from 
malformation  of  the  external  sexual  organ,  be 
an  appearance  of  hermaphroditism  in  persons 
actually  of  the  female  sex,  or  from  a  similar 
cause  there  may  be  an  appearance  of  herma- 
phroditism in  persons  actually  of  the  male  sex. 
The  differences  derived  from  the  diversity  of 
sex  in  which  spurious  hermaphroditism  occurs, 
and  the  particular  varieties  of  malformation  in 
each  sex  which  may  give  rise  to  it,  will  serve  as 

*  From  the  well-known  mythological  fable  of 
the  union  into  one,  of  the  bodies  of  Hermaphro. 
ditos  (the  son  of  Epftns,  Mercury,  and  A^foJiri, 
Venus,')  and  the  nymph  Salmacis.  See  Ovid's  Me- 
tamorphoses, lib.  iv.  lab.  8. 


HERMAPHRODITISM. 


685 


bases  on  which  we  shall  found  some  further 
subdivisions  of  this  order. 

True  hermaphroditism,  as  above  defined, 
comprehends  also,  as  shall  be  afterwards  more 
particularly  shewn,  several  very  distinct  varieties 
of  malformation.  If  we  conceive  for  a  mo- 
ment all  the  reproductive  organs  to  be  placed 
on  a  vertical  plane,  (as  we  may  suppose  them 
to  be,  though  not  with  strict  correctness,  in  the 
human  body  when  in  the  erect  posture,)  we 
shall  find  that  the  principal  of  these  varieties 
may  be  all  referred  to  three  sets  of  cases  : — ■ 
1st,  those  in  which,  if  we  drew  a  vertical 
median  line  through  this  supposed  plane,  the 
two  lateral  halves  will  be  seen  to  present  organs 
differing  in  this  respect,  that  they  belong  to 
opposite  sexual  types  ;  -2d,  others  in  which, 
if  we  bisect  the  same  plane  by  a  transverse 
horizontal  line,  there  exist  organs  of  a  different 
sex  in  the  upper  from  what  are  present  in  the 
lower  segment ;  or,  in  other  words,  the  internal 
genital  organs  belong  to  one  sex,  and  the  ex- 
ternal to  another.  In  the  two  preceding  classes 
of  cases  there  is  not  necessarily,  as  we  shall 
afterwards  more  fully  point  out,  any  malforma- 
tion by  duplicity  in  the  sexual  apparatus  of  the 


malformed  individual ;  there  is  only  one  set  of 
sexual  organs  present,  but  in  some  parts  these 
organs  are  formed  upon  the  male,  and  in  others 
upon  the  female  type.  In  the  3d  and  re- 
maining set  of  cases,  however,  there  is  really 
present  to  a  greater  or  less,  though  most  gene- 
rally only  to  a  very  partial  extent,  a  double  set 
of  sexual  organs,  having  opposite  sexual  cha- 
racters, so  that  upon  the  same  body,  and  usu- 
ally upon  the  same  side,  or  upon  the  same 
vertical  line  in  our  supposed  plane,  we  find 
coexisting  two  or  more  of  the  analogous  organs 
of  the  two  sexes.  In  accordance  with  this 
view,  we  shall  consider  the  cases  of  true  her- 
maphroditic malformation  under  the  three 
corresponding  divisions  of,  1st,  lateral;  2d, 
transverse  ;  and  3d,  vertical,  or,  more  properly, 
double  or  complex  hermaphroditism  ;  and  each 
of  these  genera  will  admit  of  some  further 
convenient  subdivisions.  But  the  mode  in 
which  we  propose  to  classify  and  consider  the 
subject  will  probably  be  at  once  more  accurately 
gathered  from  the  following  table,  than  from 
any  more  lengthened  remarks  upon  it  in  the 
present  place. 


Classification  of  hermaphroditic  malformations. 

r  From  excessive  development  of  the  clitoris, 
fin  the  Female  <  &c. 

C  From  prolapsus  of  the  uterus. 


'Spurious 


\_\n  the  Male. 


Hermaphroditism 


"Latei 


True 


al. 


S 


From  extroversion  of  the  urinary  bladder. 
From  adhesion  of  the  penis  to  the  scrotum. 
.  From  hypospadic  fissure  of  the  urethra,  &c. 

Testis  on  the  right,  and  ovary  on  the  left 
side. 

Testis  on  the  left,  and  ovary  on  the  right 
side. 


Transverse 


Vertical  or 
Double  . , 


In  commenting  upon  and  illustrating  the 
different  varieties  of  hermaphroditism  in  the 
particular  order  in  which  they  are  placed  in  the 
above  table,  we  shall,  we  believe,  by  following 
that  order,  be  able  to  take  a  graduated,  and,  at 
the  same  time,  a  correct  and  comprehensive 
view  of  the  subject,  beginning  with  the  more 
simple,  and  ending  with  the  more  complex  and 
complete  species  of  hermaphroditic  malforma- 
tion, as  seen  in  the  primary  sexual  characters, 
or  the  structure  of  the  genital  parts  themselves. 
We  shall  then  consider  at  some  length  the 
curious  and  important  physiological  subject  of 
hermaphroditism  as  manifested  in  the  secondary 
sexual  characters  of  the  system.  After  having 
done  so,  we  shall  endeavour  to  show  how  far 


$  External  sexual  organs  female,  internal  male. 
\  External  sexual  organs  male,  internal  female. 

-Ovaries  and  an  imperfect  uterus  with  male 
vesicula;  seminales,  and  rudiments  of  vasa 
deferentia. 

j  Testicles,  vasa  deferentia,  and  vesicula}  se- 
minales,  with  an  imperfect  female  uterus 
and  its  appendages. 
Ovaries  and  testicles  coexisting  on  one  or 
botli  sides,  &c. 

the  diversified  forms  of  hermaphroditic  malfor- 
mation can  be  explained  upon  our  present 
knowledge  of  the  laws  of  developement ;  point 
out  the  actual  anatomical  and  physiological 
degree  of  sexual  duplicity  which  is  liable  to 
occur,  and  the  numerous  fallacies  with  which 
the  determination  of  this  question  in  individual 
cases  is  surrounded ;  and  lastly,  in  conclu- 
sion, we  shall  offer  some  general  observations 
upon  the  causes,  &c,  of  this  class  of  abnor- 
mal formations. 

I.  SPURIOUS  HERMAPHRODITISM. 

A.  In  the  female. — There  aretwo  circumstances 
in  the  conformation  of  the  genital  organs  of  the 
female,  the  existence  of  each  of  which  has  oc- 


686 


HERMAPHRODITISM. 


casionally  given  rise  to  doubts  and  errors  with 
regard  to  the  true  sex  of  the  individual  on 
whom  they  were  found— namely,  1st,  a  pre- 
ternaturally  large  size  of  the  clitoris ;  and  2d, 
a  prolapsus  of  the  uterus;  the  enlarged  cli- 
toris in  the  one  case,  and  the  protruded  ute- 
rus in  the  other,  having  been  repeatedly  mis- 
taken for  the  male  penis. 

1.  Abnormal  developement  or  magnitude  of 
the  clitoris. — In  the  earlier  months  of  intra- 
uterine life,  the  clitoris  of  the  human  female  is 
nearly,  if  not  altogether,  equal  in  size  to  the 
penis  of  the  male  foetus ;  and  at  birth  it  is 
still  relatively  of  very  considerable  dimensions. 
From  that  period,  however,  it  ceases  to  grow  in  an 
equal  ratio  with  the  other  external  genital  parts, 
so  that  at  puberty  it  is,  as  a  general  law,  found 
not  to  exceed  six  or  eight  lines  in  length. 
But  in  some  exceptional  instances  the  cli- 
toris is  observed  to  retain  up  to  adult 
age  more  or  less  of  that  greater  pro- 
portionate degree  of  developement  which 
it  presented  in  the  embryo  of  the  third 
and  fourth  month,  thus  exhibiting  in  a  per- 
sistent form  the  transitory  type  of  structure 
belonging  to  the  earlier  stages  of  foetal  life. 
In  some  instances  where  this  occurs,  the  re- 
semblance of  the  external  female  to  the  exter- 
nal male  parts  is  occasionally  considerably  in- 
creased by  the  apparent  absence  of  the  nymphae. 
Osiander*  endeavoured  to  show  that  at  the 
third  or  fourth  month  of  foetal  life  the  nymphaa 
are  very  imperfect,  and  so  very  small  as  not  to 
be  easily  observed.  Meckel,f  however,  has 
pointed  out  that  these  organs  are  not  in  reality 
of  a  small  size  at  that  time,  but  they  are  liable 
to  escape  observation  from  the  folds  of  skin  of 
which  they  consist,  making,  at  the  period 
alluded  to,  a  perfectly  continuous  membrane 
with  the  prepuce  of  the  clitoris,  and  forming 
indeed,  in  their  origin,  only  one  common  mass 
with  this  latter  body.  When  the  ulterior 
changes,  therefore,  which  these  parts  ought  to 
undergo  in  the  natural  course  of  developement 
in  the  latter  stages  of  foetal  existence,  are  sus- 
pended or  arrested  from  about  the  end  of  the 
third  month,  there  may  not  only  coexist  with 
the  enlarged  clitoris  an  apparent  want  of  nym- 
phs, but  the  resemblance  of  the  female  to  the 
male  parts  may  be  still  further  increased  by  the 
persistence  of  the  original  intimate  connexion 
of  the  nymphse  with  the  prepuce  and  body  of 
the  clitoris,  and  by  the  consequently  continuous 
coating  of  integuments,  as  well  as  the  greater 
size  and  firmness  of  this  organ. 

Excessive  size  of  the  clitoris  would  seem  to 
be  much  less  common  among  the  natives  of 
cold  and  temperate  than  among  those  of  warm 
countries.  The  frequency  of  it  in  the  climate 
of  Arabia  may  be  surmised  from  the  fact  of 
directions  having  been  left  by  Albucasis  and 
other  surgeons  of  that  country  for  the  amputa- 
tion of  the  organ;  an  operation  which  iEtius 
and  Paulus  Eginetus  describe  as  practised 
among  the  Egyptians.    According  to  the  more 

*  Abhandlungen  iiber  die  Scheidenklappe,  in 
Denkwurdigkeiten  fiir  die  Heilkunde,  Bd.  ii.  p.  4-6. 
t  Manuel  d'Anat.  Gen.  torn.  iii.  p.  666. 


modern  observations  of  Niebuhr*  and  Son- 
nini,f  circumcision  would  seem  to  be  still 
practised  upon  the  females  of  that  country. 

This  variety  of  conformation  of  the  female 
parts  appears  to  have  been  well  known  to  the 
ancient  Greeks,  and  several  of  their  authors 
have  mentioned  the  women  so  constituted 
under  the  names  of  -rp|3a<5£;  and  E-raif  la-T/nai, 
a  class  in  which  the  celebrated  poetess  Sappho 
(mascula  Sappho )  is  well  known  to  have  been 
included.  Martial,  Tertullian,  and  other  Ro- 
man authors  have  noticed  the  same  malforma- 
tion, (fricalrices,  confricatrices,)  and  alluded 
to  the  depravity  to  which  it  led.J 

*  Beschreibung  von  Arabien,  s.  77. 
t  Voyage  dans  la  Haute  et  Basse  Egypte,  torn.  ii. 
p.  37. 

X  Mart.  Epigr.  lib.  i.  ep.  91.  ;  see  also  lib.  viii. 
ep.  66.    The  frequency  of  this  crime  in  the  ancient 
gentile  world  may  be  inferred  from  the  pointed 
manner  in  which  the  Apostle  Paul  alludes  to  it, 
Romans,  chap.  i.  26.    In  Greece  it  was  in  some 
places  forbidden  by  law,  and  in  others,  as  in  Crete, 
tolerated  by  the  state.    Seneca,  in  his  95th  ep., 
when  speaking  of  the  depravity  of  the  women 
of  his  own  age,  remarks,  "  non  mutata  fcemina- 
rum  natura,  sed  vita  est.  .  .  .  Libidine  vero,  nec 
maribus  quidem  cedunt  pati  natae.  Dii  illas  deaeque 
male  perdant,  adeo  perversum  commentae  genus 
impudicitiae  viros  ineunt."  Op.  Om.  Genev.  1665, 
p.  787.    Clemens  Alexandrinus,  in  his  Paedagogus, 
exposes  the  same  vice  :  "  et  contra  naturam  fremi- 
nae,  viros  agunt  (avSpif ovrai)  et  nubunt  et  etenim 
uxores  ducunt."      Also   Athenasus,  Deipnosoph. 
lib.  xiii.  p.  605.    Justin  Martyr,  in  his  Second 
Apology,  makes  a  still  broader  accusation.  This 
author  lived  in  the  second  century,  and  in  declaim- 
ing against  the  vices  of  that  licentious  age,  he 
alleges  that  multitudes  of  boys,  females,  and  her- 
maphrodites (androqyni  ambigui  sexus )  "  nefandi 
piaculi  gratia  per  nationem  omnem  prostant."  Op. 
Om.  Col.  1686,  p.  70.    See  also  Marcus  Antoni- 
nus, De  Seipso,  ed.  Gatakeri,  Cambr.  1652,  lib.  iii., 
note  at  the  end  by  Gataker.    On  the  extent,  among 
the  ancients,  of  the  vices  above  alluded  to,  see 
Meiner's  Geschichte  des  Verfalls  der  Sitten  und 
der  Staatsverfassung  der  Roemer,  Leipzig,  1791  ; 
Neander's  Denkwurdigkeiten,  Bd.  i.  s.  143;  Pro- 
fessor Tholuck's,  of  Halle,  Exposition  of  St.  Paul's 
Epistle  to  the  Romans,  in  the  Edinburgh  Biblical 
Cabinet,  vol.  v.  p.  102,  and  in  an  Essay  on  the 
licentious  vices,  &c,  of  the  ancients,  translated 
into  Robinson's  American  Biblical  Repository,  vol. 
ii.  p.  441.    In  the  essay  last  referred  to,  Tholuck 
incidentally  mentions  (p.  422,)  that  the  deity  Mi- 
tra  (Mithras  of  the  ancient  Persians)  was  herma- 
phrodite.   For  our  own  part  we  are  inclined  to 
believe  that  many  of  the  idols  of  the  heathenish 
mythology  of  Asia  could  be  traced  to  the  deifica- 
tion of  various  monstrosities  in  man  and^  quadru- 
peds.   (See  the  figures  of  these  idols  passim  in  C, 
Coleman's  Mythology  of  the  Hindus,  Lond.  1832; 
and  E.  Upham's  History  and  Doctrine  of  Budhism, 
Lond.  1829.)    It  perhaps  is  not  unworthy  of  no- 
tice that  the  Jewish  Talmudists,  taking  the  Hebrew 
noun  in  the  Pentateuch  answering  to  man  in  its 
individual  and  not  in  its  collective  sense,  consi- 
dered, from  Genesis,  chap.  i.  v.  21,  that  our  origi- 
nal progenitor  was  hermaphrodite.    (See  Jus  Tal- 
mud. Cod.  Erwin.  c.  2 ;  Heidegg.  Hist.  Patriarch, 
t.  i.  128  ;  C.  Bauhin  De  Monstrorum  Natura,  &c, 
lib.  i.e.  24;  and  Arnaud's  Memoire,  p.  249.)  It  is 
further  interesting  to  remark  that  Plato,  in  his 
Symposion,  introduces  Aristophanes  as  holding  the 
same  opinion.    "  The  ancient  nature,"  he  observes, 
"  of  men  was  not  as  it  now  is,  but  very  different; 
for  then  he  wa3  androgynous  both  in  form  and 


HERMAPHRODITISM. 


687 


The  dimensions  which  the  clitoris  occasion- 
ally presents  are  such  as  to  render  it,  in  respect 
of  size  alone,  not  unlike  the  male  penis.  It  is 
not  unfrequently  found  of  two  or  three  inches 
in  length,  but  sometimes  it  is  seen  five  and  six 
inches  long.  Dr.  Clark  frequently  found  the 
organ  an  inch  long,  and  thick  in  proportion, 
among  the  Ibbo  and  Mandingo  women.* 

Hallerf  and  Arnaud  I  have  collected  nume- 
rous instances  of  preternatural  size  of  the  cli- 
toris. The  former  author  alludes,  among  others, 
to  two  cases  in  which  the  organ  was  stated  to 
have  been  seven  inches  in  length ;  and  to  an- 
other, mentioned  by  Chabart,  in  which  it  was 
alleged  to  have  been  twelve  inches,- — a  size 
which  we  can  only  conceive  to  have  been  the 
result  of  disease. 

When  the  female  clitoris  is  increased  greatly 
in  size,  it  is  not  wonderful  that  it  should  be 
sometimes  mistaken  for  the  male  penis, — the 
female  organ  in  the  Mammalia  naturally  differ- 
ing from  the  male  only  in  regard  to  its  smaller 
dimensions,  its  not  being  perforated  by  the 
urethra,  and  its  wanting  the  corpus  spongio- 
sum,— a  peculiarity  or  defect  of  structure  that 
exists  as  the  natural  type  of  formation  in  the 
penis  of  male  reptiles.  In  the  human  subject 
the  organs  are  composed  internally  of  the  same 
kind  of  erectile  tissue,  and  when  we  descend  in 
the  animal  scale,  and  examine  their  relations  in 
the  males  and  females  of  the  same  species,  we 
find  some  still  more  striking  analogical  peculi- 
arities of  structure.  Thus,  in  several  of  the 
Carnivora  and  Rodentia,  as  in  the  lioness,  cat, 
racoon,  bear,  marmot,  &c.  the  clitoris  contains 
a  small  bone  like  that  belonging  to  the  penis 
of  the  males  of  the  same  species ;  and  amongst 
the  Monotremata  and  Marsupiata  the  clitoris 
of  the  female,  like  the  penis  of  the  male,  is 
surmounted  by  a  bifid  glans.  In  a  species  of 
lemur  (Loi'is  gracilis  or  Slenops  tardigra- 
dus ),  the  clitoris  is  of  a  very  large  size ;  and 
the  urethra,  as  first  pointed  out  by  Daubenton,§ 

name,"("v^p°>"'l"'v  *ai  El^°C  Kai  wofwt.)  Probably  from 
the  licentious  purposes  alluded  to  by  Justin  Martyr, 
or  from  the  weak  and  imbecile  character  of  her- 
maphrodite individuals,  the  word  avSpoyno?  came  in 
latter  times  to  signify  effeminate  and  luxurious. 
The  ancient  lexicographer  Hesychius  gives  it  this 
meaning  ;  and  Theodoret,  in  his  Therap.,  speaks  of 
Bacchus  as  being  licentious,  effeminate,  and  an- 
drogynous— (yuvvic  tuv,  nai  flnXuJpittff,  xoi  avJpojoivo?.  ) 

*  Home's  Comp.  Anat.  vol.  iii.  p.  317.  On  the 
peculiarities  of  the  external  genital  organs  in  va- 
rious African  tribes,  see  a  learned  paper  by  Prof. 
Miiller  in  his  Archiv  fuer  Anatomic  for  1834.  Ht. 
iv.  s.  319.,  with  ample  references  to  the  observa- 
tions and  opinions  of  Levaillant,  liarrow,  Peron, 
Lesner,  Lichtenstein,  Burchcll,  Somerville,  &c. 
See  also  Otto,  in  his  Neue  Seltenc  Bcobaehtungcn 
zur  Anatomie,  p.  135,  shewing  the  very  prominent 
external  female  parts  of  different  African  tribes  to 
consist  differently,  1 ,  of  enlarged  nymphae,  2,  of 
enlarged  labia,  and  3,  of  the  enlarged  clitoris. 

t  El.  Phys.  torn.  vii.  part  ii.  p.  81,  82. 

X  Dissertation  sur  les  Hermaphrodites,  p.  372. 
See  also  Homberg,  De  Excrescentia  Clitoridis  nimia, 
Jena,  1671  •,  Troncliin,  De  Clitoridc,  JLugd.  1736; 
and  Ploucquet's  Literatura  Mcdica,  art.  Clitoris 
Magna,  torn.  i.  p.  299. 

§  Audibert,  Histoire  Nat.  des  Singes,  tab.  ii. 
fig.  8. 


runs  forward  and  opens  at  its  anterior  extre- 
mity between  the  branches  of  its  glans,  imita- 
ting, in  this  point  of  structure,  the  penis  of  the 
male  among  the  Mammalia. 

In  the  human  subject  the  mere  enlargement 
of  the  clitoris  alone  has  seldom  of  itself  given 
rise  to  errors  with  regard  to  the  sex  of  the  indi- 
vidual, except  in  young  children  ;  but  it  has 
frequently  happened  that  along  with  it  other 
minor  malformations  have  coexisted,  so  as  to 
render  the  sexual  distinction  much  more  ambi- 
guous. In  women  possessing  this  peculiarity 
of  structure  we  sometimes  observe,  for  in- 
stance, the  clitoris  not  only  resembling  the 
penis  in  size,  but  it  has  an  indentation  at  the 
point  of  the  glans,  imitating  the  orifice  of  the 
urethra ;  and  occasionally  the  glans  is  actually 
perforated  to  a  certain  extent  backwards,  or 
the  body  of  the  clitoris  is  drilled  more  or  less 
imperfectly  with  a  canal  like  that  of  the  male 
urethra.  In  other  instances  the  canal  and 
orifice  of  the  female  vagina  are,  by  an  excess 
of  development  in  the  median  line  of  the 
body,  much  contracted  or  nearly  shut  up,  the 
vulva  being  closed  by  a  strong  membrane  or 
hymen,  and  the  labia  cohering  so  as  to  give  the 
parts  a  near  resemblance  to  the  united  or  closed 
perinffium  and  scrotum  of  the  male.  Further, 
in  one  or  two  very  rare  cases  which  have  been 
put  upon  record,  the  ovaries  and  Fallopian 
tubes  seem  to  have  descended  through  the  in- 
guinal rings  into  the  labia,  thus  giving  an  ap- 
pearance of  the  presence  of  testicles ;  and  a 
fallacy  seems  to  have  occurred  in  some  cases 
from  the  presence  of  roundish  masses  of  fat 
in  this  situation  simulating  more  or  less  the 
same  male  organs. 

Besides,  it  often  happens  in  those  women 
who  present  more  or  fewer  of  these  peculiarities 
of  conformation  in  the  external  genital  parts, 
that  the  general  or  secondary  sexual  characters 
of  the  female  are  wanting,  or  developed  in  a 
slighter  degree  than  natural,  owing  probably 
to  the  malformations  of  the  external  organs 
being  often  combined  with  some  coexisting 
anomalies  in  those  more  important  internal  re- 
productive organs,  the  healthy  structure  and 
action  of  which  at  the  time  of  puberty  appear 
to  exercise  so  great  an  influence  on  the  deve- 
lopment of  the  peculiar  general  conformation 
and  moral  character  of  the  female.  Thus  the 
features  are  sometimes  hard,  the  figure  and 
gait  rather  masculine,  the  mamma?  slightly 
developed,  the  voice  is  deep-toned,  and  the 
chin  and  upper  lip  are  occasionally  covered 
with  a  quantity  of  hair.  In  fact,  in  some 
marked  cases  the  whole  external  character  ap- 
proaches to  that  of  the  male,  or,  more  pro- 
perly speaking,  occupies  a  kind  of  neutral 
ground  between  that  of  the  two  sexes.  Some 
of  the  more  striking  examples  of  this  first  va- 
riety of  spurious  hermaphroditism  in  the  fe- 
male will  sufficiently  illustrate  the  above  re- 
marks. 

Dr.  Ramsbotham*  has  briefly  described  the 
genital  parts  of  an  infant,  that  was  christened 
and  looked  upon  as  a  boy,  until  dissection  after 

*  Medical  Gazette,  xiii.  p.  184. 


688 


HERMAPHRODITISM. 


death  shewed  that  the  sex  was  actually  female. 
The  uterus  and  other  female  organs  (Jig.  287, 
c  c  c)  were  present  and  apparently  naturally 

Fig.  287. 


formed ;  but  the  clitoris  (b)  was  fully  as  large, 
and  in  appearance  closely  resembled  the  penis 
of  a  male  of  the  same  age.  At  its  anterior 
extremity  there  was  a  sulcus  («),  which  was 
not  the  entrance  of  the  urethra,  but  terminated 
in  a  cul-de-sac. 

Columbus*  and  De  Graaff  give  two  similar 
examples  of  the  same  form  of  spurious  her- 
maphroditism in  young  children,  in  which  the 
true  sex  was  only  fully  ascertained  by  dis- 
section after  death.  In  relation  to  the  clitoris 
in  the  case  described  by  Columbus,  that  author 
states  that  this  organ  was  furnished  with  two 
muscles  only,  and  not  with  four,  as  in  the  per- 
fect male. 

In  a  reputed  hermaphrodite  woman,  Gallay  J 
found  after  death  the  clitoris  to  be  three  and  a 
half  inches  long,  and  three  inches  and  four 
lines  in  circumference.  The  glans  and  prepuce 
were  well  developed.  The  urethra  ran  as  in 
man  through  the  body  of  the  penis  and  its 
glans.  The  labia,  nympha,  vagina,  &c.  were 
natural,  and  the  internal  female  organs,  the 
ovaries,  Fallopian  tubes,  and  uterus,  are  de- 
scribed as  scirrhous.  This  woman  had  been 
married,  but  never  had  any  children  ;  her  ca- 
tamenia,  however,  had  been  very  regular.  She 
had  a  considerable  quantity  of  hair  upon  her 
face,  and  her  voice  was  harsh  and  masculine. 

In  a  child  of  two  years  of  age,  Schneider,§ 
on  dissection  after  death,  could  find  neither 
the  labia  externa  nor  interna,  nor  any  trace  of 
the  ordinary  cleft  between  them.  The  clitoris 
was  an  inch  and  a  half  long,  and  externally 
resembled  most  perfectly  a  male  penis  fur- 
nished with  a  glans  and  prepuce ;  but  it  was 
imperforate,  having  only  at  its  anterior  extre- 
mity a  small  spot  marking  the  situation  of  the 
opening  of  the  urethra  in  the  male.  Some 

*  De  Re  Anatomica,  lib.  xv.  p.  493. 
t  Op.  Om.  cap.  iii.  xv.  or,  De  mulierum  organis 
gen.  inserv.  with  a  plate, 
t  Arnaud,  1.  c.  p.  309. 

i  Jahrbiicher  der  Staatsarzneikunde,  (1809), 
s.  193. 


lines  below  there  was  an  opening  by  which 
the  urine  was  evacuated.  This  opening  formed 
the  entrance  to  the  vagina,  which  was  found  of 
the  usual  length,  and  with  the  characteristic 
rugee.  The  canal  of  the  urethra  was  found 
entering  its  roof,  but  in  such  a  manner  that 
the  urine  was  always  evacuated  very  slowly 
and  by  drops  only  from  the  external  opening. 
All  the  internal  female  sexual  organs  were 
natural. 

M.  Beclard*  has  left  us  a  very  detailed  and 
interesting  description  of  an  example  of  spu- 
rious hermaphroditism  referable  to  the  present 
variety,  and  exhibited  at  Paris  in  1814.  The 
subject  of  the  case,  Marie  Madeline  Lefort, 
was  at  that  time  sixteen  years  of  age.  The 
proportions  of  the  trunk  and  members,  and  of 
the  shoulders  and  pelvis,  and  the  conformation 
and  dimensions  of  this  last  part  of  the  body, 
were  all  masculine;  the  volume  of  the  larynx 
also,  and  the  tone  of  the  voice  were  those  of 
an  adolescent  male ;  a  beard  was  appearing  on 
the  upper  lip,  chin,  and  region  of  the  parotids; 
some  hairs  were  growing  in  the  areola  around 
the  nipple  ;  and  the  mammas  were  of  a  mode- 
rate size.  The  inferior  extremities  were  fur- 
nished with  an  abundance  of  long  hard  hairs. 
The  symphysis  pubis  was  elongated  as  in  man ; 
the  mons  veneris  rounded,  and  the  labia  ex- 
terna were  covered  with  hair.  The  clitoris  was 
10J  (?)  inches  (27  centimetres)  in  length  when 
at  rest,  but  somewhat  more  when  erect ;  its 
glans  was  imperforate,  and  covered  in  three- 
fourths  of  its  circumference  with  a  mobile  pre- 
puce. The  body  of  this  enlarged  clitoris  was 
furnished  inferiorly  with  an  imperfect  canal, 
which  produced  a  depression  in  it,  instead  of 
that  prominence  of  this  part  which  exists  in  the 
male  penis.  This  canal  was  pierced  along  its 
under  surface  and  median  line  by  five  small 
holes  capable  of  admitting  a  small  stylet ;  and 
one  or  more  similar  apertures  seemed  to  exist 
in  it  after  it  reached  backwards  within  the  va- 
gina. The  labia  were  narrow  and  short,  and 
the  vulva  or  sulcus  between  them  was  superfi- 
cial, being  blocked  up  by  a  dense  membrane, 
which,  under  the  pressure  of  the  finger,  felt  as 
if  stretched  towards  the  anus  over  a  cavity.  At 
its  anterior  part,  or  below  the  clitoris,  there  was 
an  opening  capable  of  admitting  a  sound  of 
moderate  size,  and  this  sound  could  be  made 
to  pass  backwards  behind  the  membrane  closing 
the  vulva,  which,  when  felt  between  the  point 
of  the  instrument  and  the  finger,  seemed  about 
twice  as  thick  as  the  skin.  The  urine  was 
passed  by  this  opening,  and  also,  according  to 
the  report  of  the  individual  herself,  through 
the  cribriform  holes  in  the  canal  extending 
along  the  inferior  surface  of  the  urethra.  By 
the  same  opening  the  menstrual  fluid  escaped, 
as  Beclard  ascertained  on  one  occasion  by  per- 
sonal examination.  She  had  menstruated  re- 
gularly from  the  age  of  eight  years,  considered 
herself  a  female,  and  preferred  the  society  of 
men. 

In  this  interesting  case  we  have  present  all 
the  secondary  sexual  characters  of  the  male, 

*  Bulletins  de  la  Faculte  for  1815,  p.  273. 


HERMAPHRODITISM. 


689 


with  some  of  the  female  genital  organs  deve- 
loped in  so  excessive  a  degree  as  to  approach 
in  several  points  the  more  perfect  structure  of 
them  in  man.  The  impossibility,  however,  as 
mentioned  by  Beclard,  of  finding  any  bodies 
like  testicles  in  the  labia  or  in  the  course  of 
the  inguinal  canals,  and  more  particularly  the 
well-ascertained  fact  of  the  individual  menstru- 
ating, can  leave  no  doubt  as  to  the  nature  of 
her  sex.  The  perforation  of  the  enlarged  cli- 
toris with  the  imperfect  urethra  is  interesting, 
when  compared  with  the  peculiarities  that  we 
have  formerly  alluded  to,  of  this  part  in  the 
female  Loris,  as  pointing  out,  what  we  have  so 
often  occasion  to  observe  in  human  monstrosi- 
ties, a  type  of  structure  assumed  by  a  mal- 
formed organ  similar  to  the  normal  type  of  struc- 
ture of  the  same  organ,  in  some  of  the  inferior 
animals. 

Arnaud*  has  represented  and  described  at 
great  length  an  interesting  example  of  herma- 
phroditic malformation  that  seems  referable  to 
the  head  of  spurious  hermaphroditism  in  the 
female,  although  there  are  two  circumstances 
in  the  history  of  the  case  which  have  led  some 
authors  to  doubt  the  accuracy  of  this  opinion  ; 
and  the  opportunity  that  was  afforded  of  ascer- 
taining the  true  structure  of  the  parts  after 
death  was  unfortunately  lost  through  careless- 
ness and  neglect.  The  subject  of  the  malfor- 
mation, aged  35,  passed  in  society  for  a  female, 
and  came  to  Arnaud  complaining  of  a  small 
tumour  (fig.  288,  e)  in  the  right  groin,  which 


Fig.  288. 


had  incommoded  hermuchduring  her  whole  life. 
On  examining  this  body,  Arnaud  was  led  to 
believe  that  it  was  a  testicle,  and  he  found  a 
similar  tumour  (_/')  situated  nearer  the  inguinal 
ring  on  the  left  side.  The  bags  that  contained 
them  represented  very  exactly  the  labia  externa. 
The  clitoris  (a)  was  two  inches  and  nine  lines 
in  length,  and  placed  between  the  labia  at  their 
upper  angle.  The  glans  (b)  was  well  formed, 
and  though  imperforate  at  its  extremity,  it  pre- 
sented a  small  depression  which  ran  backwards 
along  the  whole  inferior  border  of  the  clitoris, 
indicating  the  situation  of  a  collapsed  urethral 
canal,  that  seemed  pervious  for  some  length  at 

*  Dissertation  sur  les  Hermaphrodites,  p.  265, 
pi.  x. 

VOL.  II. 


its  posterior  part,  as  it  became  distended  when 
the  patient  evacuated  the  bladder.  The  ori- 
fice (c),  however,  from  which  the  urine  actually 
flowed,  occupied  the  situation  in  which  it  exists 
in  the  perfectly  formed  female.  There  was  not 
any  vaginal  opening,  and  the  individual  men- 
struated per  anum.  At  each  menstrual  period 
a  tumour  (d)  always  appeared  in  the  perinaeum, 
which  gradually  increased  in  size,  becoming,  in 
the  course  of  three  or  four  days,  as  large  as  a 
small  hen's  egg.  When  the  perinaeal  tumour 
had  reached  this  size,  blood  began  to  flow 
from  the  anus,  although  no  haemorrhoids  or 
other  disease  of  the  bowel  was  present.  At 
these  periods  the  individual  had  often  expe- 
rienced very  alarming  symptoms,  and  in  order 
to  avert  these,  Arnaud  was  induced  to  make  an 
opening  into  the  soft  yielding  space  at  which 
the  perinaeal  tumour  above  alluded  to  appeared; 
and  at  a  considerable  depth  he  found  a  cavity 
two  inches  in  circumference,  and  about  two 
and  a  half  in  breadth,  having  projecting  into  it 
at  one  point  an  eminence  which  was  supposed 
from  its  situation  to  be  possibly  the  os  uteri. 
At  the  next  period  the  menstrual  fluid  came 
entirely  by  the  artificial  perinaeal  opening,  and 
the  usual  severe  attendant  symptoms  did  not 
supervene.  From  inattention,  however,  to  the 
use  of  the  tent,  the  opening  was  allowed  to 
become  completely  shut,  so  that  at  the  sixth 
return  of  the  menses  they  flowed  again  by  the 
anus,  and  were  accompanied  by  the  old  train 
of  severe  symptoms.  The  individual  lived  for 
several  years  afterwards.  Her  conformation  of 
body  was  remarkable.  Her  skin  was  rough, 
thick,  and  swarthy;  she  had  a  soft  black  beard 
on  her  face  ;  her  voice  was  coarse  and  mascu- 
line ;  her  chest  narrow ;  her  mammas  were  flat 
and  small  ;  her  arms  lean  and  muscular ;  her 
hands  large,  and  her  fingers  of  very  considerable 
length  and  strength.  The  form,  in  fact,  of  the 
upper  part  of  her  body  was  masculine,  but  in 
the  lower  part  the  female  conformation  predo- 
minated. The  pelvis  was  wide  and  large,  the 
os  pubis  very  elevated,  the  buttocks  large,  the 
thighs  and  legs  round,  and  the  feet  small. 

In  this  remarkable  instance,  if  we  do  not  go 
so  far  as  to  conceive  the  coexistence  of  some 
of  the  internal  organs  of  both  sexes,  we  must, 
from  the  well-ascertained  fact  of  the  menstrual 
evacuations,  allow  the  person  at  least  to  have 
been  a  female.  In  that  case  we  can  only  sup- 
pose the  tumours  in  the  labia  to  be  the  ovaries 
descended  into  that  situation  ;  and  to  the  same 
excess  of  development  which  has  produced  this 
effect,  we  may  attribute  the  closure  of  the 
vaginal  orifice,  and  the  formation  of  the  imper- 
fect urethral  canal  in  the  body  of  the  clitoris. 

Spurious  hermaphroditism  from  preternatural 
enlargement  of  the  clitoris  has  been  recognised 
among  some  of  the  lower  animals.  Rudolphi* 
has  noticed  a  mare  of  this  kind  that  had  a 
clitoris  so  large  as  almost  to  shut  up  the  en- 
trance into  the  vagina.    Lecoqf  has  detailed 

*  Riulolphi's  Bemeikun^en  auf  einer  Reise,  &c. 
Bd.  i.  s.  79.  See  a  case  also  figured  by  Ruysch  la 
his  Thesaurus  Anat.  lib.  viii.  no.  53. 

t  Jouin.  Piat.  <!e  Mtd.  Vet.  1827,  p.  103. 

2  z 


G90 


HERMAPHRODITISM. 


the  case  of  a  calf  which  Gurlt*  believes  to 
belong  to  the  present  head.  Neither  testicles 
nor  scrotum  were  observed  externally,  and  the 
penis  or  enlarged  clitoris,  which  occupied  its 
normal  situation,  was  apparently  perforated  by 
the  urethra,  and  crooked  upwards  so  as  to 
throw  the  urine  in  that  direction.  Mery  f 
shewed  by  dissection  the  true  sex  of  a  monkey, 
the  length  of  whose  clitoris  had  deceived  some 
observers  with  regard  to  the  true  sex  of  the 
animal.  The  enlarged  clitoris  was  furrowed 
on  its  inferior  surface.  The  clitoris  of  the 
female  Quadrumana  is,  as  shall  be  afterwards 
more  particularly  mentioned,  relatively  larger 
than  in  the  human  subject,  and  retains  in  a 
greater  degree  the  size  and  type  of  structure  of 
this  organ  in  the  embryo. 

We  may  here  further  mention  that,  as  pointed 
out  by  Blumenbach,!  the  clitoris  and  orifice  of 
the  urethra  are  placed  at  some  distance  from 
the  vagina  and  in  front  of  it,  in  the  rat,  mouse, 
hamster,  &c.  This  normal  structure  has  some- 
times been  mistaken  for  an  hermaphroditic  mal- 
formation .§ 

2.  From  prolapsus  of  the  uterus. — It  may 
at  first  appear  strange  that  this  occurrence 
should  ever  lead  to  any  difficulty  in  ascertain- 
ing the  sex  of  the  individual,  though  not  only 
non-professional  observers  but  even  the  most 
intelligent  medical  men  have  occasionally  been 
so  far  misled  by  the  similarity  of  the  protruded 
organ  to  the  male  penis,  as  to  mistake  a  female 
for  a  male.  Of  this  circumstance  some  curious 
illustrations  are  on  record. 

M.  Veay,  physician  at  Toulouse,  has  inserted 
in  the  Philosophical  Transactions  of  London, 
vol.  xvi.  p.  282,  a  brief  account  of  the  case  of 
Marguerite  Malause  or  Malaure,  who  was 
entered  as  a  female  patient  in  the  Toulouse 
Hospital  in  1686.  Her  trunk,  face,  &c.  pre- 
sented the  general  configuration  of  a  female, 
but  in  the  situation  of  the  vulva  there  was  a 
body  eight  inches  in  length  when  on  its  fullest 
stretch,  and  resembling  a  perfectly  formed  male 
penis  in  all  respects,  except  in  not  being  pro- 
vided with  a  prepuce.  Through  the  canal 
perforating  this  body  she  was  alleged  to  eva- 
cuate her  urine,  and  from  its  orifice  M.  Veay 
had  himself  an  opportunity  of  seeing  the  men- 
strual fluid  flow.  After  being  examined  by 
several  physicians  she  was  pronounced  to  be 
more  male  than  female,  and  ordered  by  the 
civil  authorities  to  exchange  the  name  of  Mar- 
guerite for  that  of  Amaud,  and  to  wear  male 
attire.  In  1693  she  visited  Paris  in  her  male 
habiliments,  and  reputed  herself  endowed  with 
the  powers  of  both  sexes.  The  Parisian  phy- 
sicians and  surgeons  who  examined  her  seem  all 
to  have  accorded  in  opinion  with  the  faculty  of 
Toulouse,  until  M.  Saviard||  saw  her  and  de- 
tected the  supposed  penis  to  be  merely  the 
prolapsed  uterus.  He  reduced  the  protruded 
organ,  and  cured  the  patient.  Upon  the  enigma 

*  Lehrbuch  der  Pathol.  Anat.  Bd.  ii.  s.  193. 
t  Hist,  de  l'Acad.  (1686)  torn.  i.  p.  345. 
$  Corap.  Anat.  p.  335. 

4  Doebel,  in  Nov.  Liter.  Maris  Balthici  (1698), 
p.  238. 

||  Recueil  d'Observations  Chirurgicales,  p.  150. 


of  her  hermaphroditism  being  thus  solved,  she 
was  permitted  by  the  king,  at  her  own  request, 
to  assume  again  her  female  name  and  dress. 

Sir  E.  Home*  detected  a  case  of  reputed 
hermaphroditism  of  the  same  description  as  the 
last,  in  a  French  woman  of  twenty-five  years  of 
age,  who  exhibited  herself  in  London,  and 
pretended  to  have  the  powers  of  a  male.  The 
cervix  uteri  was  uncommonly  narrow,  and  pro- 
jected several  inches  beyond  the  external  open- 
ing of  the  vagina.  The  everted  mucous  surface 
of  the  vagina  had,  from  constant  exposure,  lost 
its  natural  appearance  and  resembled  the  ex- 
ternal skin  of  the  penis.  The  orifice  of  the  os 
tinea  had  been  mistaken  for  the  orifice  of  the 
urethra.  The  prolapsus  had  been  observed  at 
an  early  age,  and  had  increased  as  the  woman 
grew  up. 

Valentinf  mentions  another  analogous  in- 
stance of  sexual  ambiguity  produced  by  a 
prolapsus  of  the  uterus.  In  this  case  the 
husband  mistook  the  displaced  organ  for  the 
penis,  and  accused  his  wife  of  having  "  cum 
sexu  virili  necquicquam  commune." 

A  case  quoted  at  great  length  by  A  maud  J 
from  Duval,  of  reputed  hermaphroditism  in  a 
person  that  was  brought  up  as  a  woman,  and 
married  at  twenty-one  years  of  age  as  a  male, 
but  who  was  shortly  afterwards  divorced  and 
imprisoned,  and  ordered  again  by  the  Court 
of  Rouen  to  assume  the  dress  of  a  woman, 
appears  to  us  to  belong  very  probably  to  the 
present  division  of  our  subject,  the  reputed 
penis  being  described  as  placed  within  the 
vagina.  The  recorded  details  of  the  case, 
however,  are  not  so  precise  as  to  leave  us  with- 
out doubt  in  regard  to  its  real  nature. 

In  cases  such  as  those  now  mentioned,  in 
which  the  prolapsed  uterus,  or,  more  properly 
speaking,  the  prolapsed  uterus  and  vagina  have 
been  mistaken  for  the  penis,  it  appears  proba- 
ble that  the  neck  of  the  uterus  must  have  been 
preternaturally  long  and  narrow,  otherwise  it 
would  be  difficult  to  account  for  the  apparent 
small  diameter  and  great  length  of  the  prolapsed 
organ.  Among  Professor  Thomson's  collection 
of  anatomical  drawings  of  diseased  structures 
there  is  one  of  an  uterus  containing  in  its  body 
a  fibro-calcareous  tumour,  and  having  a  neck 
of  three  inches  in  length.  M.  Cruveilhier  § 
has  represented  a  similarly  diseased  uterus  with 
a  neck  of  between  five  and  six  inches.  An 
organ  shaped  in  this  manner,  whether  from 
congenital  malformation  or  acquired  disease, 
would,  when  prolapsed  for  some  time,  repre- 
sent, we  conceive,  a  body  resembling  in  form 
and  size  those  observed  in  Saviard's  and  Home's 
cases.  The  prolapsus  arising  from  a  protrusion 
of  an  ordinary  shaped  uterus  is  generally  of  a 
greater  diameter  and  roundness. 

This  second  species  of  spurious  female  her- 
maphroditism is  not  observed  among  the  lower 
animals. 

B.  Spurious  hermaphroditism  in  the  male. — 

*  Comp.  Anat.  vol.  iii.  p.  318. 

t  Pandectae  Medico- Legales,  t.  i.  p.  38,  Casus  xii. 

j  Mem.  sur  les  Hermaphr.  p.  314-18. 

§  Anat.  Pathol,  liv.  xiii.  PI.  iv. 


HERMAPHRODITISM. 


691 


Malformed  males  have  been  more  often  mis- 
taken for  females  than  the  reverse.  The  varieties 
of  malformation  in  persons  actually  male,  that 
are  liable  to  lead  to  mistakes  with  regard  to 
their  true  sex,  appear  to  be,  1st,  extrophy  or 
extroversion  of  the  urinary  bladder;  2d,  ad- 
hesion of  the  inferior  surface  of  the  penis  to 
the  scrotum ;  and  3d,  and  principally,  fissure 
of  the  inferior  part  of  the  urethra  and  of  the 
scrotum  and  perinaeum. 

1.  Extroversion  of  the  urinary  bladder. — 
For  a  full  description  of  this  malformation  we 
must  refer  to  the  articles  Bladder  and  Mon- 
strosity. This  malformation  is  known  to 
occur  more  frequently  in  the  male  than  in  the 
female,  and  when  present  in  the  former  it  has 
occasionally  given  rise  to  a  supposition  of  her- 
maphroditism, the  red  fungous  mass  formed 
by  the  mucous  membrane  of  the  protruded 
posterior  wall  of  the  bladder,  and  situated 
above  the  pubis,  having  been  mistaken  for  the 
female  vulva, — an  error  which  has  probably 
been  the  more  readily  committed  from  the 
uterus  and  seminal  ducts,  and  sometimes  also, 
as  in  an  instance  described  by  A.  Fraenkel,*  a 
part  of  the  intestinal  canal  opening  upon  the 
surface  of  the  exposed  poition  of  bladder.  In 
some  instances  of  this  malformation  occurring 
in  man,  the  external  male  sexual  organs  are 
very  imperfectly  formed,  or  can  scarcely  be 
said  to  be  at  all  present.  In  other  cases  the 
scrotum  is  of  the  natural  form,  with  the  two 
testicles  in  it;  and  the  penis  is  of  considerable 
size,  though  almost  always  fissured  on  its  upper 
surface  from  the  epispadic  or  open  state  of  the 
urethra. 

An  example  of  supposed  hermaphroditic 
malformation  briefly  described  by  Ruerfe,h 
which  seems  referable  to  this  variety  will  be 
sufficient  to  illustrate  it.  "  In  the  year  1519 
an  hermaphrodite  or  androgynus,"  he  remarks, 
"  was  born  at  Zurich,  perfectly  formed  from 
the  umbilicus  upwards,  but  having  at  this  part 
a  red  mass  of  flesh,  beneath  which  were  the 
female  genitals,  and  also  under  and  in  their 
normal  situation  those  of  the  male." 

2.  Adhesion  of  the  inferior  surface  of  the 
penis  to  the  scrotum  by  a  band  of  integuments. 
— This  state  of  parts  has  occasionally  given 
rise  to  the  idea  of  hermaphroditism,  the  penis 
being  so  bound  down  as  not  to  admit  of  erec- 
tion, and  the  urine  passing  in  a  direction 
downwards,  so  as  to  imitate  the  flow  of  it  from 
the  female  parts. 

In  a  boy  of  seven  years  of  age  regarding 
whom  Brand  I  was  consulted,  the  penis  was 
confined  in  this  manner  to  the  scrotum  by 
abnormal  adhesions.  He  had  been  baptized 
and  reared  as  a  girl,  but  by  a  slight  incision 
the  adherent  organ  was  liberated,  and  the 
parents  were  convinced  of  the  mistake  that  they 
had  committed  in  regard  to  the  sex  of  their 
child.    The  difficulty  of  determining  the  true 

•  De  Organorum  Generationis  Deform.  Rarissi- 
ma,  Berlin,  1825,  with  a  plate. 

t  De  Conceptu  et  Generatione  Hominis,  p.  44. 

X  Case  of  a  boy  who  had  been  mistaken  for  a 
girl.    London,  1788. 


sex  of  the  boy  was  increased  by  the  testicles 
not  having  descended  into  the  scrotum. 

Wrisberg*  mentions  two  similar  instances 
in  persons  of  the  respective  ages  of  nineteen 
and  forty-six.  He  relieved  the  adherent  penis 
in  the  first  case  by  operation. 

3.  Fissure  of  the  inferior  part  of  the  ure- 
thra, perinaum,  fyc. — This  species  of  mal- 
formation, which  has  perhaps  more  frequently 
than  any  other  given  rise  to  the  idea  of  the 
person  affected  with  it  being  the  subject  of 
hermaphroditism,  evidently  consists  in  an  arrest 
of  the  development  of  the  external  male  sexual 
parts. 

At  an  early  stage  of  the  development  of  the 
embryo,  the  various  central  sexual  organs  are, 
like  all  the  other  single  organs  situated  on  the 
median  line  of  the  body,  found  to  be  composed 
of  two  separate  and  similar  halves,  divided 
from  each  other  by  a  vertical  fissure,  which, 
after  the  originally  blind  extremity  of  the  intes- 
tinal canal  has  opened  upon  the  perineum, 
forms  a  common  aperture  or  cloaca  for  the 
intestinal  canal,  and  also  for  the  urinary  and 
genital  apparatus,  both  of  which  are,  in  their 
primary  origin,  prolongations  from  the  lower 
part  of  that  canal.  After  a  time,  (about  the 
second  month  in  the  human  embryo,)  the 
opposite  sides  of  this  cloaca  gradually  approxi- 
mate, and  throw  out  two  corresponding  folds, 
which  by  their  union  constitute  a  septum  that 
separates  the  rectum  from  the  canal  or  portion 
of  the  fissure,  that  still  remains  common  to 
the  urinary  and  generative  organs ;  and,  in  the 
same  way,  by  two  similar  and  more  anterior 
folds,  the  urethra  of  the  female,  and  the  pelvic 
portion  of  that  of  the  male  is  subsequently 
produced.  After  this  in  the  female  the  process 
of  median  reunion  does  not  proceed  further, 
and  the  primary  perinatal  fissure  remains,  form- 
ing the  vulva  and  vagina.  In  the  male,  how- 
ever, the  development,  when  normal,  goes  on 
to  a  greater  extent,  and  the  sides  of  the  opening 
become  so  far  united  as  ultimately  to  leave  only 
the  comparatively  contracted  canal  of  the  urethra 
to  serve  as  a  common  passage  for  both  the 
internal  urinary  and  genital  organs ;  and  the 
situation  of  the  line  of  junction  of  the  opposite 
sides  of  the  original  perineal  cleft  remains  still 
marked  out  in  the  adult,  by  the  raphe  existing 
in  the  median  line  of  the  scrotum.  The  two 
lateral  parts  of  the  female  clitoris  unite  together 
into  one  solid  body,  having  on  its  under  sur- 
face a  slight  groove  or  channel,  indicative  of 
the  line  of  conjunction  of  its  two  component 
parts ;  and  the  urethra  is  left  to  open  at  the 
root  of  this  imperforated  organ.  In  the  male, 
on  the  contrary,  the  two  primitive  halves  of 
the  penis,  consolidated  together  at  an  early 
stage  along  the  course  of  their  upper  surfaces, 
come,  in  the  progress  of  development,  to  unite 
inferiorly  in  such  a  manner  with  one  another  as 
to  form  a  tubular  prolongation  of  the  pelvic 
portion  of  the  canal  of  the  urethra,  which  is 
gradually  extended  forwards  along  the  body  of 
the  penis  and  ultimately  through  its  glans. 

Many  of  the  malformations  to  which  the 

*  Comment.  Med.  &c.  Arg.  p.  534. 

2  Z  2 


692 


HERMAPHRODITISM. 


male  genital  organs  are  liable  may  be  traced  to 
stoppages  in  the  above  process  of  development, 
the  character  of  the  malformation  depending 
upon  the  period  of  the  development  at  which 
the  arrest  takes  place,  and  varying  consequently 
in  degree  from  the  existence  of  a  cloaca  or 
permanent  primitive  fissure  common  to  the 
intestinal,  urinary,  and  generative  organs,*  to 
that  want  of  closure,  to  a  greater  or  less  extent 
in  different  instances,  of  the  inferior  surface  of 
the  canal  of  the  urethra  in  the  body  of  the 
penis,  or  in  its  glans,  which  is  generally  known 
under  the  name  of  hypospadias.  When  the 
development  of  the  male  organs  is  arrested, 
immediately  after  the  two  septa  respectively 
separating  the  canals  of  the  intestine  and  urethra 
from  the  original  perinaeal  cleft  are  formed, 
and  consequently  when  this  perineal  fissure 
and  that  running  along  the  inferior  surface  of 
the  penis  are  still  open,  the  external  genital 
parts  often  come  to  present  at  birth,  and  during 
the  continuance  of  life,  a  striking  resemblance 
to  the  conformation  of  the  external  organs  of 
the  female,  and  the  resemblance  is  frequently 
rendered  greater  by  the  coexistence  of  other 
malformations  of  the  male  organs.  In  these 
cases  the  imperfect  and  undeveloped  penis  is 
generally  of  small  size,  and,  at  the  same  time, 
from  being  imperforate,  may  readily  be  mis- 
taken for  the  clitoris;  the  two  halves  of  the 
divided  scrotum  have  the  appearance  of  the 
two  labia  externa;  the  two  labia  externa  or 
nymphs  are  sometimes  represented  by  the 
lateral  divisions  of  the  penis  forming  two  folds, 
which  run  backwarks  along  the  internal  surfaces 
of  the  split  scrotum ;  and  the  cleft  in  the 
perinaeum  corresponds  in  situation  and  direc- 
tion, and  occasionally  also  in  size  and  form, 
with  the  canal  of  the  vagina;  this  cleft  is 
generally  lined  also  by  a  red  mucous  membrane 
that  is  kept,  like  the  natural  female  parts,  con- 
stantly moistened  by  the  secretions  of  the 
follicles  with  which  it  is  provided ;  its  mucous 
membrane  occasionally  presents  irregular  eleva- 
tions imperfectly  representing  the  caruncute 
myrtiformes;  and,  further,  the  opening  of  the 
urethra  at  the  root  of  the  diminutive  and  im- 
perforate penis  serves  still  more  to  assimilate 
the  malformed  parts  to  the  natural  conformation 
of  the  female  organs.  In  a  number  of  cases, 
however,  the  apparent  analogy  to  the  female 
parts  is  rendered  less  striking  by  the  perinaeal 
cleft  being  small  or  altogether  absent,  the 
urethral  orifice  at  the  root  of  the  penis  often 
forming  the  only  opening  leading  to  the  internal 
urinary  and  generative  parts,  and  the  halves  of 
the  scrotum  in  such  instances  being  frequently 
more  or  less  perfectly  united.  Generally  the 
seminal  ducts,  and  sometimes  also  the  ducts  of 
Cowper's  glands,  are  seen  opening  on  the 
surface  of  the  urethra  or  supposed  vaginal 
canal,  at  a  short  distance  from  its  external 
orifice. 

In  males  malformed  in  the  manner  described, 
the  testicles  are  seldom  found  in  the  divided 

*  See  on  this  malformation  in  the  human  subject 
(the  normal  form  of  structure  in  birds,  &c.)  Meckel 
on  kloakbildung  in  his  I'alh,  Anat.  Bd.  i.  s.  693. 


scrotum  at  birth,  but  commonly  they  descend 
into  it  through  the  inguinal  rings  towards  the 
period  of  puberty  ;  and  in  several  instances  on 
record,  in  which  the  sex  of  the  individual  had 
been  mistaken  for  that  of  a  female,  the  tumours 
formed  in  the  groin  at  that  time  by  the  organs 
in  their  descent  have  been  erroneously  regarded 
and  treated  as  hernial  protrusions.  At  the 
same  time  it  occasionally  happens  that  with 
the  descent  of  the  testicles,  and  the  arrival  of 
puberty,  the  diminutive  penis  enlarges  in  size, 
and  the  individual  assumes  more  or  less  fully 
the  habits  and  attributes  of  the  male.  In 
several  instances  on  record  this  change  has, 
under  venereal  excitation,  appeared  to  occur 
suddenly,  and  persons  formerly  reputed  female 
have  thus  unexpectedly  found  themselves  pro- 
vided with  an  erectile  male  penis.  These 
various  changes  are  occasionally  postponed  for 
a  considerable  period  beyond  the  usual  term 
of  puberty. 

In  a  few  rare  instances  one  testicle  only  de- 
scends through  the  inguinal  ring,  and  occasion- 
ally they  both  remain  throughout  life  within  the 
abdomen,  in  or  near  the  situation  in  which  they 
are  originally  developed,  imitating  in  this  ab- 
normal state  the  normal  position  of  the  same 
organs  in  many  of  the  males  among  the  lower 
animals.  In  a  number  of  instances  in  which 
the  testicles  are  thus  retained  within  the  cavity 
of  the  abdomen,  they  are  found  small  and  im- 
perfectly developed,  and  from  the  want  of  their 
usual  physiological  influence  upon  the  consti- 
tution, the  whole  physical  and  moral  character 
of  the  malformed  individual  frequently  presents 
a  considerable  approximation  to  that  of  the 
female,  or,  as  we  should  perhaps  more  justly 
express  it,  never  attains  the  perfection  of  the 
male,  but  preserves  that  kind  of  common  or 
neutral  state  exhibited  by  the  constitution  of 
both  sexes  before  the  specific  sexual  characters 
of  each  are  developed  at  the  time  of  puberty. 

Numerous  curious  examples  of  mistakes 
having  been  committed  with  regard  to  the  sex 
of  males  affected  with  the  above  species  of  mal- 
formation have  now  been  put  on  record,  from 
the  time  at  which  Iphis,  the  daughter  of  Ligdus, 
king  of  Crete,  was  conceived  to  be  changed 
into  a  man  by  the  miraculous  interference  of 
Isis,  down  to  the  present  day.  Pliny,  (lib.  vii. 
chap.iv.)  has  noticed  several  cases;  and  in  the 
treatise  of  Duval  on  hermaphrodites  a  number 
of  additional  instances  are  collected  from  Livy, 
Trallian,  and  others,  some  of  them  no  doubt 
invested  (as  most  of  the  details  regarding  her- 
maphrodites in  the  older  authors  are)  in  much 
misrepresentation  and  fable,  but  others  bearing 
every  mark  of  accuracy  and  authenticity.  In 
more  modern  times  the  sexes  of  individuals 
have  often  been  mistaken  in  consequence  of 
this  variety  of  malformation.  Jean  Chroker* 
relates,  in  apparently  the  most  authentic  man- 
ner, the  case  of  Magdelain  Mugnoz,  a  nun  of 
the  order  of  St.  Dominique  in  the  town  of 
Ubeda,  who  was  changed,  as  he  supposes,  into 
a  male,  seven  years  after  having  taken  the  vows. 

*  Fat.  Histor.  cent.  i.  and  Arnaud,  Dissertation 
sur  les  Hermaphrodites,  p.  200. 


HERMAPHRODITISM. 


693 


He  was  expelled  the  convent,  assumed  the 
male  dress,  and  took  the  name  of  Francois. 
The  sequel  of  the  story,  as  told  by  Chroker, 
would  seem  to  shew  that  his  sexual  desires  be- 
came extremely  strong,  and  he  is  said  to  have 
been  ultimately  condemned,  whether  justly  or 
not,  under  an  accusation  of  rape. 

Portal*  quotes  from  Tigeon  the  story  of  a 
person  who  was  brought  up  as  a  female,  and 
afterwards  was  considered  to  be  suddenly 
changed  by  a  surprising  metamorphosis  into  a 
male,  and  in  citing  this  case  Dr.  Hodgkin,f  of 
London,  mentions,  on  the  authority  of  a  friend, 
a  recent  instance  of  an  equally  sudden  deve- 
lopment of  the  male  sex  in  a  previously  reputed 
female.  Similar  instances  in  which  the  proper 
sex  of  malformed  males  was  unexpectedly  dis- 
covered under  the  excitement  of  sexual  passion 
at  the  period  of  puberty  are  mentioned  by  Pare, 
Tulpius,  and  others. 

SchweikardJ  has  recorded  an  instance  of  a 
person  baptized  and  brought  up  as  a  female, 
and  whose  true  sex  was  only  at  last  disclosed 
by  his  requesting,  at  the  age  of  forty-nine,  per- 
mission to  marry  a  young  woman  then  preg- 
nant by  him.  On  examination  it  was  disco- 
vered that  the  penis  was  slender  and  scarcely 
two  inches  long ;  the  right  testicle  only  had 
descended  into  the  scrotum,  and  the  urethra 
opened  at  the  root  of  the  penis,  but  its  orifice 
was  placed  in  such  a  manner  that  during  mic- 
turition the  urine  was  thrown  along  the  groove 
or  channel  on  the  under  surface  of  the  penis,  so 
as  to  appear  to  issue  from  its  anterior  extremity. 
The  two  halves  of  the  scrotum  were  so  far 
united  that  they  left  only  a  small  oval  opening 
between  the  anterior  part  of  the  raphe  and  the 
roots  of  the  corpora  cavernosa.  In  this  open- 
ing the  orifice  of  the  urethra  was  situated. 

Dr.  Baillie §  has  mentioned  a  case  which 
appears  to  belong  in  all  probability  to  the  pre- 
sent division.  The  subject  of  it  was  twenty- 
four  years  of  age.  She  had  always  passed  in 
society  as  a  woman,  and  came  for  consultation 
to  the  Nottingham  Hospital  on  account  of  her 
menses  never  having  appeared  ;  a  circumstance, 
however,  that  had  in  no  way  affected  her 
health.  The  spurious  vagina  consisted  of  a 
cul-de-sac  two  inches  in  depth.  The  penis 
was  of  the  size  of  the  female  clitoris,  but  there 
were  no  nymphse.  The  labia  were  more  pen- 
dulous than  usual,  and  contained  each  of  them 
a  body  resembling  a  testicle  of  a  moderate  size, 
with  its  cord.  The  look  of  the  individual  was 
remarkably  masculine,  with  plain  features,  but 
no  beard.  The  mammae  resembled  those  of  a 
woman.  The  person  had  no  desire  or  partiality 
for  either  sex. 

Adelaide  Preville,  who  had  been  married  as 
a  female,  died  in  the  Hotel  Dieu  of  Paris.  In 
examining  the  body  of  this  individual  after 

'  Hist,  de  l'Anat.  torn.  ii.  p.  52. 
t  Catalogue  of  Guy's  Hospital  Museum,  part  ii. 
sect.  xi. 

X  Hufeland's  Journal  der  Prak.  Heilkunde.  Bd. 
xvii.  No.  18. 

Morbid  Anatomy,  p.  410,  2d  edit. 


death,  Giraud*  found  that,  except  a  perineal 
cleft  or  false  vagina  consisting  of  a  cul-de-sac 
placed  between  the  bladder  and  rectum,  nothing 
else  resembling  the  female  sexual  apparatus 
could  be  detected,  while  all  the  organs  belong- 
ing to  the  male  sex  were  present 

Ottof  has  described  and  represented  (Jig- 289) 


Fig.  289. 


a  case  of  the  present  species  of  hermaphroditism 
in  an  individual  whose  history  is  remarkable. 
The  person  had  lived  ten  years  in  the  state  of 
wedlock  with  three  different  men  ;  but  at  the  age 
of  thirty-five  an  action  of  divorce  was  brought 
against  her  by  her  third  husband,  accusing  her 
of  being  affected  with  some  disease  of  the  sexual 
parts  that  rendered  the  connubial  act  on  his 
part  extremely  difficult  and  painful.  After 
some  difference  of  opinion  between  the  two 
medical  men  to  whose  professional  examination 
the  wife  was  submitted,  it  was  at  last  consi- 
dered that  she  was  in  reality  a  male,  and  the 
case  came  at  last  under  the  investigation  of  the 
members  of  the  Royal  Medical  College  of 
Silesia,  who  confirmed  this  opinion.  The  im- 
perforated penis  (6)  was  one  inch  and  a  half  in 
length  ;  the  perineal  fissure  (e)  forming  the 
false  vagina  was,  at  the  posterior  part  of  its 
orifice,  bounded  by  a  distinct  frenulum,  but 
was  of  a  size  sufficient  to  receive  the  glans  of 
the  husband  for  an  inch  and  a  half  in  depth. 
This  cavity,  as  well  as  the  internal  surfaces  of 
the  two  lobes  (a  «)  of  the  divided  scrotum, 
were  lined  with  a  vascular  mucous  membrane. 
At  the  bottom  of  it  the  round  orifice  of  the 
urethra  (d)  was  seen  to  open  ;  and  at  the  same 

*  Recueil  Period,  de  la  Soc.  de  Med.  torn.  ii. 
p.  315,  or  Moureau's  Hist.  Nat.  de  la  Fcmme,  t.  i. 
p.  243,  (with  a  figure  of  the  parts.) 

f  Neue  Scltcne  Bcobachtungcn  zur  Anatomic, 
&c.  p.  123. 


694 


HERMAPHRODITISM. 


point  a  hard  mass  could  be  felt,  probably  con- 
sisting of  the  prostate  gland ;  and  more  up- 
wards and  outwards,  nearly  in  the  natural 
situation  of  the  bulb,  was  seen  the  split  urethra 
(c)  with  a  row  of  three  considerably  sized  open- 
ings (./,'/)>  which,  under  pressure  and  irritation 
of  the  genital  parts,  gave  out  several  drops  of  a 
transparent  mucous  fluid.  Otto  considers  these 
openings  as  the  extremities  of  the  ducts  of  the 
prostate  and  Cowper's  glands,  and  of  the  semi- 
nal canals.  The  right  half  of  the  scrotum  con- 
tained a  small  testicle  about  the  size  of  that  of  a 
boy  of  ten  years  of  age  ;  the  left  testicle  lay  like- 
wise external  to  the  abdominal  ring,  and  was 
still  softer  and  smaller  than  the  right.  Both 
were  furnished  with  spermatic  cords.  The  ge- 
neral configuration  of  the  individual  was  strong, 
muscular,  and  meagre  ;  the  beard  was  thin  and 
soft,  and  the  face,  maram;e,  thorax,  pelvis,  and 
extremities  were  evidently  masculine. 

Along  with  the  preceding  instances  we  are 
inclined  to  classify  the  case  of  Maria  Nonzia, 
as  detailed  by  Julien  and  Soules.*  This  indi- 
vidual was  born  in  Corsica  in  1695,  was  twice 
married  as  a  female,  and  at  last  divorced  in 
1739  by  her  second  husband,  after  having  lived 
sixteen  years  in  wedlock.  The  penis  was  two 
inches  in  length,  but  imperforate,  and  the  mea- 
tus urinarius  was  placed  at  its  root.  Two 
bodies,  like  ordinary  sized  testicles,  and  fur- 
nished with  spermatic  cords,  were  felt  in  the 
divided  scrotum  ;  and  there  was  a  narrow  false 
vagina  or  perineal  canal  one  inch  and  three 
Jines  in  depth,  and  crossed  at  its  upper  extre- 
mity by  two  small  traversing  membraneous 
bridles.  The  character  and  appearance  of  the 
person  were  masculine;  the  visage  was  beard- 
ed ;  the  mammae  were  as  fully  developed  as  in 
the  adult  woman,  but  the  nipples  were  each 
surrounded  with  hair. 

So  far  as  the  preceding  details  go,  they  seem 
amply  sufficient  to  justify  us  in  considering 
Maria  Nonzia  as  a  malformed  male ;  and  we 
are  still  inclined  to  take  this  view  of  the  case, 
notwithstanding  the  statement  inserted  in  the 
report  of  Julien  and  Soules,  that  the  menses 
were  present  as  in  other  women.  For  not  to 
insist  upon  the  circumstance  that  the  reporters 
do  not  shew  that  they  made  any  minute  or 
satisfactory  inquiry  into  this  alleged  fact,  and 
not  improbably  took  it  upon  the  mere  word  of 
the  subject  of  the  case,  who  was  necessarily 
greatly  interested  in  maintaining  the  reputed 
female  character,  it  would  be  requisite,  in  any 
such  paradoxical  instance,  to  ascertain  if  the 
discharge  actually  agreed  in  character  with  the 
menstrual  fluid,  or  was  not  pure  blood,  the  re- 
sult of  an  haemorrhage  from  the  genito-urinary 
passages,  or  from  the  rectum,  where,  as  in  other 
parts  of  the  body,  this  form  of  disease  frequently 
assumes  a  periodical  type.  We  would  be  in- 
clined to  apply  even  still  more  strongly  these 
remarks  to  the  celebrated  case  of  Hannah  Wild, 
detailed  by  Dr.  Sampson.-)-    This  person  had 

*  Observ.  sur  l'Hist.  Nat.  sur  la  Physique  et  sur 
la  Peinture,  torn.  i.  p.  18,  with  a  plate. 

t  Ephem.  Nat.  Curios.  Dec.  i.  an.  iii.  p.  323. 


evidently  the  male  genital  organs  malformed  in 
the  manner  mentioned  with  regard  to  the  other 
cases  included  under  the  present  section,  and 
possessed  all  the  secondary  sexual  peculiarities 
of  the  male ;  so  that  we  can  only  receive  with 
great  doubt  and  distrust  the  alleged  existence 
of  the  menstrual  discharge,  and  the  more  so,  as 
this  is  evidently  stated  on  the  report  of  the 
subject  of  the  case  alone,  who,  deriving  a  pre- 
carious subsistence  from  the  exhibition  of  his 
malformations,  had  a  deep  interest  in  amplify- 
ing every  circumstance  that  could  enhance  the 
public  curiosity  with  respect  to  the  reality  of 
his  hermaphroditic  character. 

At  the  same  lime,  however,  it  must  be  re- 
marked that  in  some  instances  of  spurious  her- 
maphroditism, it  is  found  extremely  difficult  or 
even  impossible  during  life  to  determine  with 
precision  the  true  or  predominant  sex  of  the 
malformed  individual ;  and  in  regard  to  several 
well-known  cases  on  record,  we  find  on  this 
point  the  most  discrepant  opinions  offered  by 
different  authors.  Thus  while  Morand,*  Ar- 
naud,f  and  DeliusJ  described  Michel- Anne 
Drouart  as  a  male ;  Guyot,§  Ferrein,||  and 
Caldanif  maintained  that  this  person  was  a 
female;  and  Mertrud**  regarded  the  individual 
as  an  example  of  a  real  hermaphrodite. 

A  useful  lesson  of  caution  to  us  against  our 
forming  too  decided  and  dogmatic  an  opinion 
in  cases  in  which  the  sexual  conformation  ap- 
pears in  any  marked  degree  doubtful,  has 
lately  been  offered  in  the  instance  of  Maria- 
Dorothee  Duriee,  or,  as  this  individual  was 
named  in  the  latter  years  of  'his  life,  Charles 
Durge.  While  Metzgerff  considered  this  per- 
son as  a  specimen  of  that  kind  of  equivocal 
sexual  formation  to  which  the  designation  of  her- 
maphroditism is  truly  applicable,  Hufeland,IJ 
Mursinna,§§  Gall,  Brookes,||||  and  othersllH 
declared  the  sex  of  Duriee  to  be  in  reality 
female;  and  Stark,***  Mertens,fft  and  the 
Members  of  the  Faculty  of  Medicine  at  Paris  J  J  J 
were  equally  positive  in  regarding  the  indivi- 
dual as  merely  a  malformed  male.  The  dis- 
section of  the  body  of  Duriee  by  Professor 
Mayer  has,  as  we  shall  afterwards  state  more  in 
detail,  shewn  the  sexual  conformation  of  this 
individual  to  consist  of  a  true  mixture  of  both 
the  male  and  female  organs. 

*  Mem.  de  l'Acad.  des  Sc.  1750,  p.  165. 
t  Dissert,  sur  les  Hermaphr.  p.  298. 
J  Frank,  Sammlung.  Th.  viii.  s.  398. 

I  Mem.  de  l'Acad.  des  Sc.  1756,  p.  71. 

II  lb.  1767,  p.  205. 

«j[  Mem.  della  Societa  Italiaua,  t.  vii.  p.  130. 
**  Arnaud,  loc.  cit.  p.  293. 
tt  Gericht. -medic.  Abhandlungen.  Bd.  i.  s.  177. 
Journ.  der  Praktischen  Heilkunde,   Bd.  xii. 
s.  170. 

&§  Journ.  fur  die  Chirurgie,  Arzneikunde,  &c. 
Bd.  i.  s.  555. 

Illl  Medical  Gazette  for  October,  1836. 

^f^f  Von  dem  Neuangekommen.  Hermaphrod. 
Berl.  1801. 

***  Neuen  Archiv.  fur  die  Geburtshiilfe.  Bd.  ii. 
s.  538. 

fttBeschreibungder  mannlichen  Geschleehtslheile 
von  M.  D.  Durrier.    Leipzig,  1802,  with  two  plates, 
ttt  Med.  Gaz.  for  October,  1836. 


HERMAPHRODITISM. 


695 


In  attempting  to  determine  the  true  sex  in 
such  doubtful  instances  of  sexual  formation  as 
those  which  we  have  been  now  considering,  we 
are  inclined  to  attribute  very  little  weight  to  the 
nature  of  the  sexual  desires  of  the  malformed 
individual,  as  we  have  already  found  Adelaide 
Preville,  the  dissection  of  whose  body  shewed 
him  to  be  in  reality  a  man,  living  for  some 
years  before  death  in  the  capacity  of  a  wife, 
and  the  same  remark  might  be  further  illus- 
trated by  a  reference  to  Otto's  and  other  cases. 

A  species  of  spurious  hermaphroditism  simi- 
lar in  character  to  that  which  we  have  just  de- 
scribed in  man,  is  occasionally  met  with  in  the 
males  of  our  domestic  quadrupeds,  and  has 
been  amply  illustrated,  as  it  occurs  in  these 
animals,  by  Professor  Gurlt  in  his  work  on 
Veterinary  Medicine.  In  instances  of  this 
malformation  among  the  animals  to  which  we 
refer,  the  hypospadic  male  penis  has  usually 
been  found  of  a  tortuous  and  winding  form 
and  of  small  size.  In  the  cases  in  which  the 
fissure  of  the  parts  extends  through  the  scrotum, 
a  false  vagina  is  seldom  formed,  as  in  man,  for 
the  scrotum  in  most  quadrupeds  lies  too  remote 
from  the  perineum,  and  consequently  from  the 
normal  situation  of  the  vagina,  for  this  purpose; 
but  in  some  examples  this  division  appears  to 
be  carried  upwards  into  the  perinsum  itself, 
leaving  a  vaginal-like  opening,  in  which  the 
urethra  terminates.  The  testicles,  as  in  man, 
are  sometimes  retained  within  the  abdomen, 
and  in  other  instances  descend  into  the  scrotum. 
They  are  frequently  small  in  size.  The  mamma 
or  udder  seems  to  be  often  well  developed. 

This  variety  of  hermaphroditic  malforma- 
tion has  been  met  with  in  the  horse  by  Pen- 
chenati;*  in  the  he-goat  by  Haller;f  and  in  the 
ram  by  the  same  author,J  and  by  Wagner,§ 
Wepfer,||  Stark,1T  Gurlt,**  KauwBoerhaave,ft 
and  A.  Cooper.}!  We  have  seen  an  excellent 
specimen  of  this  malformation  in  the  last- 
mentioned  animal  in  the  museum  of  Dr. 
Handyside  of  Edinburgh.  In  this  instance 
the  internal  male  organs  are  all  perfect ;  the 
large  testicles  are  situated  in  the  halves  of  the 
split  scrotum  ;  the  penis  is  small  and  imperfo- 
rate, and  a  furrow  running  along  its  inferior 
surface  is  continued  backwards  and  upwards 
along  the  perinaeum  to  within  a  short  distance 
from  the  anus,  where  it  leads  into  a  canal,  into 
which  the  urinary  bladder  and  seminal  ducts 
open.  This  canal  is  evidently  formed  of  the 
dilated  pelvic  portion  of  the  male  urethra;  its 
orifice  is  comparatively  contracted,  but  corres- 
ponds in  situation  with  the  vulva  of  the  fe- 
male.   We  have  seen  a  second  similar  case  in 

*  Mem.  de  l'Acad.  de  Turin,  torn.  v.  p.  18. 
t  Comment.  Soc.  Keg.  Sc.  Getting,  torn.  i.  p.  2, 
tab.  i. 
t  Ibid.  p.  5,  tab.  ii. 

6  Ephem.  Nat.  Curios.  Cent.  i.  ii.  p.  235. 
I)  Miscell.  Nat.  Curios.  Dec.  i.  An.  iii.  (1672,) 
p.  255. 

f  Ibid.  Dec.  iii.  Ann.  v.  vi.,  p.  669. 
**  Lehrbuch,  p.  193. 

tt  Nov.  Comment.  Acad.  Petropolit.  torn.  i. 
(1750,)  p.  315,  tab.  xi. 

tt  Catalogue  of  Guy's  Hospital  Museum,  No. 
2546. 


the  ram  in  the  possession  of  Professor  Dick  of 
the  Veterinary  School  of  Edinburgh. 

There  is  another  variety  of  malformation  of 
the  male  parts  occasionally  found  in  quadru- 
peds, which  is  allied  in  its  nature  to  the  pre- 
ceding. In  this  second  species  all  the  exter- 
nal male  sexual  organs  are  small ;  the  short 
penis  lies,  when  not  in  a  state  of  erection,  upon 
the  posterior  surface  of  the  enlarged  udder, 
and  the  imperfectly  developed  testicles  are  ge- 
nerally retained  within  the  abdomen ;  or,  if 
they  have  passed  out  of  that  cavity,  they  are 
found  situated  in  the  substance  of  the  udder. 
The  vasa  deferentia,  prostate,  aud  Cowper's 
glands  are  usually  of  their  normal  size  and  ap- 
pearance. This  imperfect  hermaphroditic  for- 
mation appears  to  be  not  rare  among  horses, 
several  instances  of  it  in  this  animal  having 
been  now  described  by  Arnaud,*  Gohier,f 
VoImar,J  Pallas,§  Virey,||  and  Gurlt.1T  An- 
selmo**  and  Lecoqft  nave  met  with  this  variety 
of  malformation  in  the  bull ;  and  Sandford  }J 
has  described  an  instance  in  the  calf  which 
seems  referable  to  the  same  head.  Gurlt§§  also 
notices  the  preparation  of  an  analogous  case  in 
the  calf,  as  preserved  in  the  museum  at  Berlin. 

II.  TRUE  HERMAPHRODITISM. 

True  hermaphroditism  exists  as  the  normal 
type  of  sexual  conformation  in  several  classes 
of  the  vegetable  and  animal  kingdom.  Almost 
all  phanerogamic  plants,  with  the  exception  of 
those  included  under  the  class  Dicecia,  are  fur- 
nished with  both  male  and  female  reproductive 
organs,  placed  either  upon  the  same  flower, 
or,  as  in  the  Linnaean  class  Moncecia,  upon 
different  flowers  in  the  same  individual.  In  the 
class  Polygamia  various  exceptional  genera  are 
included,  that  present  indiscriminately  upon 
the  same  individual,  or  upon  different  indivi- 
duals of  the  same  species,  male,  female,  and 
hermaphrodite  flowers,  and  which  thus  form  a 
kind  of  connecting  link  between  the  general 
hermaphroditic  form  of  phanerogamic  vegeta- 
bles, and  the  unisexual  type  of  the  monoecious 
flowers,  and  the  dioecious  plants. 

From  anormalities  in  developement,  these 
normal  conditions  of  the  sexual  type  in  the 
different  members  of  the  vegetable  kingdom 
are  occasionally  observed  to  be  changed.  Thus, 
among  the  Dicecia,  individual  plants  are  some- 
times, in  consequence  of  a  true  malformation, 
observed  to  assume  an  hermaphroditic  type  of 
structure ;  or,  on  the  other  hand,  in  hermaphro- 
ditic plants  more  or  fewer  flowers  are  occa- 

*  Arnaud  sur  les  Hermaphrodites,  p.  282. 

t  Mem.  et  Observ.  sur  la  Chir.  et  la  Med.  Vet. 
torn.  i.  p.  18. 

t  Archiv.  fur  Thierheilkunde,  Bd.  iii.  s.  292. 

§  Ueschaft.  der  Gesellschaft  naturforcb.  Freunde 
zu  Berlin,  Bd.  iii.  s.  296. 

|J  Journal  Compl.  des  Sc.  Med.  torn.  xv.  p.  140. 

II  Lehrbuch  der  Path.  Anat.  13d.  ii.  p.  189  ;  and 
tab.  viii.  fig.  6. 

**  Mem.  del'  Acad,  des  Sc.  de  Turin,  torn.  ix. 
p.  103.  fig.  1-3. 

tt  Journ.  Prat,  de  Med.  Vet.  1827,  p.  102. 

tt  Med.  and  Phys.  Journal,  vol.  ii.  p.  305,  with 
two  drawings. 

§§  Loc.  cit.  p.  191. 


6V6 


HERMAPHRODITISM. 


sionally  found  unisexual,  in  consequence  of  the 
arrested  developement  of  one  order  of  their 
sexual  organs  ;  and  again, though  still  more  rarely, 
from  an  excess  of  evolution,  a  double  set  of 
male  parts,  or  a  double  set  of  stamens,  is  seen 
developed  on  some  of  the  individual  flowers. 

In  the  animal  kingdom  we  find  instances  of 
a  perfect  hermaphroditic  structure  as  the  normal 
form  of  the  sexual  type  in  the  Trematodes  and 
Cestoides  among  the  Entozoa,  in  the  abranchial 
Annelida,  in  the  Planaria,  and  in  many  of  the 
Mollusca,  particularly  in  the  Pteropoda,  and  in 
several  families  among  the  Gasteropoda.  In 
some  of  these  animals  that  are  thus  naturally 
hermaphroditic,  the  fecundation  of  the  female 
organs  of  the  bisexual  individual  is  accom- 
plished by  its  own  male  organs;  but  in  others, 
although  the  anatomical  structure  is  strictly  her- 
maphroditic, yet  the  union  of  two,  or,  as  some- 
times happens,  of  more  individuals  is  neces- 
sary to  complete  the  sexual  act ;  and  during  it 
the  female  organs  of  each  are  respectively  im- 
pregnated by  the  male  organs  of  the  other. 

In  the  Nematodes  and  Acanthocephali  among 
the  Entozoa,  and  in  the  Cephalopoda  and  Pecti- 
nibranchiate  Gasteropoda  among  the  Mollusca, 
as  well  as  in  all  symmetrically  formed  animals, 
or,  in  other  words,  in  those  whose  bodies  are 
composed  of  an  union  of  two  similar  halves, 
as  in  Insects,  and  the  Arachnida,  Crustacea,  and 
Vertebrata,  the  male  and  female  organs  of  re- 
production are  placed  each  upon  a  different 
individual  of  the  species,  constituting  the  ba- 
sis of  distinction  between  the  two  sexes.  In 
such  animals  a  mixture  of  more  or  fewer  of 
the  reproductive  organs  of  the  two  sexes  upon 
the  same  individual  appears  occasionally  as  a 
result  of  abnormal  formation  ;  but  the  male  and 
female  organs  that  coexist  in  these  cases  are 
seldom  or  never  so  anatomically  perfect  as  to 
enable  the  malformed  being  to  exercise  the 
proper  physiological  function  of  either  or  of 
both  of  the  two  sexes.  This  form  of  true  her- 
maphroditism or  abnormal  mixture  upon  the 
same  individual  of  the  organs  of  the  two  sexes 
in  the  higher  animals,  has  been  termed  unnatu- 
ral or  monstrous,  in  opposition  to  the  natural 
hermaphroditism  which  exists  as  the  normal 
type  of  sexual  structure  in  some  of  the  lower 
orders  of  animals,  and  in  phanerogamic  plants. 
The  malformation  itself  is  observed  to  differ 
greatly,  both  in  nature  and  degree,  in  different 
cases,  varying  from  the  presence  or  superaddi- 
tion  of  a  single  organ  only  of  theoppositeor  non- 
predominant  sex,  up  to  the  development  and 
co-existence  of  almost  all  the  several  parts  of 
the  two  sexes  upon  the  same  individual.  In 
describing  the  malformation,  we  shall  classify  its 
various  and  diversified  forms  under  the 
three  general  orders  pointed  out  in  our  table, 
including,  1st,  lateral ;  2dly,  transverse  ;  and 
3dly,  double  or  vertical  hermaphroditism. 

A.  Lateral  hermaphroditism.  —  According  to 
the  opinion  of  many  physiologists  of  the  pre- 
sent day,  the  two  lateral  symmetrical  halves  of 
the  body,  and  even  the  two  halves  of  all  its 
single  mesial  organs,  are  originally  developed 
in  a  great  degree  independently  of  one  another. 
Granting  this  point  in  the  doctrine  of  eccentric 


developement,  we  can  easily  conceive  how,  in 
the  same  embryo,  an  ovary  might  be  formed  on 
one  Wolffian  body,  and  a  testicle  on  the  other; 
or,  in  other  words,  how  female  organs  might  be 
developed  on  one  side,  and  male  organs  on  the 
other.  It  is  the  existence  of  such  an  unsymme- 
trical  type  of  sexual  structure  upon  the  two  op- 
posite sides  of  the  body  of  the  same  individual, 
that  constitutes  the  distinctive  characteristic  of 
lateral  hermaphroditism. 

Instances  of  this  species  of  true  hermaphro- 
ditic malformation  have  been  observed  in  many 
different  classes  of  animals,  as  well  as  in  the 
human  subject. 

Individual  examples  are  sometimes  observed 
among  insects,  particularly  among  the  Lepido- 
ptera,  in  which  all  the  different  parts  of  the  two 
sides  or  lateral  halves  of  the  body  are  formed 
after  opposite  sexual  types.  We  shall  after- 
wards have  occasion  to  notice  different  exam- 
ples of  this  form  of  lateral  hermaphroditism  as 
seen  in  the  general  conformation  of  the  body, 
but  may  here  state  that  in  two  or  three  in- 
stances such  malformed  insects  have  been  care- 
fully dissected,  and  found  to  present,  in  the  ana- 
tomical structure  of  their  sexual  organs,  a  mix- 
ture of  the  organs  of  the  male  and  female. 

In  a  MelitcBu  didymus  described  by  Klug,* 
the  general  external  characters  were  those  of  the 
male,  but  the  left  eye,  palpus,  and  antenna, 
and  the  left  sexual  fang,  were  smaller  than  in 
individuals  belonging  to  this  sex ;  and  the  left 
antenna  was  annulated  with  white  and  yellow 
at  the  apex,  while  the  right  was  of  one  colour. 
On  dissection,  the  various  male  sexual  parts 
were  present,  and  they  had  appended  to  them 
a  free  female  ovary  situated  upon  the  left,  and 
united  to  no  other  organ. 

In  a  Gastrophaga  quercifolia  dissected  by 
Schultz,  and  described  by  Rudolphi,f  the  left 
side  appeared  externally  male,  and  the  right 
female,  with  a  distinct  line  of  separation  through- 
out the  whole  body.  On  dissection,  Schultz  dis- 
covered an  ovarium  upon  the  right  side,  and 
two  testes  upon  the  left.  The  oviduct  of  the 
ovary  joined  the  canal  of  the  vasa  deferentia 
about  two  inches  before  its  termination;  and 
the  spermatheca  was  connected  with  the  com- 
mon evacuating  duct.  The  two  testicles  on  the 
left  side  were  placed  one  behind  the  other,  and 
connected  by  a  thin  vessel.  The  spermatic 
duct  belonging  to  one  of  the  testicles  imme- 
diately received,  as  in  the  Lepidoptera,  the  spi- 
ral vessel  ;  further  beyond,  and  on  the  opposite 
side,  a  second  vessel,  which  appeared  to  con- 
sist of  the  rudimental  spermatic  duct  of  the 
other  testicle,  opened  into  it.  The  oviduct  of 
the  ovary  joined  the  canal  of  the  vasa  deferen- 
tia about  two  inches  before  its  termination  in 
the  penis,  and  a  female  spermatheca  was  con- 
nected with  the  common  distended  evacuating 
duct.  I 

*  Fioriep's  Notizen,  vol.  x.  p.  183. 
t  Abhandlung.  der  Koenig.  Akad.  zu  Berlin  fur 
1825,  s.  55. 

f  See  also  drawings  of  the  body  and  genital  or- 
gans of  an  hermaphrodite  Sphinx  populi  in  Fischer's 
Oryctographie  du  Gouveinement  de  Moscou  (Mos- 
cow, 1830..) 


HERMAPHRODITISM. 


697 


A  well-marked  example  of  lateral  herma- 
phroditism among  the  Crustacea  has  been  re- 
corded by  Dr.  Nicholls.*  In  a  lobster  (Anta- 
eus murium )  he  found  on  the  right  side  of  the 
body  a  female  sexual  aperture  in  its  normal 
situation  at  the  root  of  trie  third  leg,  and  con- 
nected with  a  regularly  formed  oviduct,  full  of 
ova.  On  the  left  side  of  the  animal  there  was 
a  male  sexual  aperture  placed,  as  usual,  at  the 
root  of  the  fifth  leg,  and  connected  internally 
with  an  equally  perfect  testicle  and  spermatic 
cord.  The  general  external  conformation  of 
the  animal  corresponded  with  its  internal  sexual 
structure,  the  right  lateral  half  of  the  body 
presenting  all  the  secondary  characters  and  pe- 
culiarities of  the  female,  and  the  left  all  those  of 
the  male;  so  that  if  split  from  head  to  tail,  (to 
use  Dr.  Nicholls' mode  of  expression,)  the  animal 
would  have  been  perfectly  female  on  the  right 
side,  and  perfectly  male  on  the  left. 

The  investigations  of  Sir  E.  Homef  led  phy- 
siologists some  years  ago  to  believe  that  among 
Fishes  lateral  hermaphroditism  constituted  the 
natural  type  of  sexual  formation  in  the  genera 
Myxine  and  Petromyzon  ;  but  the  later  and 
more  accurate  observations  of  RathkeJ  have 
shewn  that  these  species  are  strictly  bisexual, 
and  that  the  opposite  opinion  had  arisen  from 
the  kidneys  of  the  female  having  been  mistaken 
for  the  male  testicles.  Various  instances,  how- 
ever, are  on  record  of  fishes,  known  to  be  nor- 
mally bisexual,  presenting  from  abnormal  deve- 
lopement  a  lateral  hermaphroditic  structure,  or  a 
roe  on  one  side,  and  a  milt  on  the  other.  Such 
an  hermaphroditic  malformation  has  been  met 
with  in  the  genera  Salmo,^  Gadus,\\  and  Cy- 
prinus*\  and  in  the  Merlangus  vulgaris,**  Aci- 
penser  husorff  and  Esox  lucius-H 

Of  lateral  hermaphroditism  in  Birds,  we  have 

*  Phil.  Trans,  for  1730,  no.  413,  vol.  xxxvi.  p. 
290,  with  drawings  of  the  animal,  and  of  its  repro- 
ductive organs. 

t  Phil.  Trans,  for  1823.  Art.  xii. 

X  Bemerkungen  ueber  den  Innern  Bau  der 
Pricke,  s.  119.  See  also  additional  observations  by 
the  same  author  in  Miiller's  Arcliiv  fur  Anatomie, 
&c.  for  1836.  Heft.  ii.  s.  171.  The  older  error  of 
Cavolini,  who  supposed  that  he  had  detected  two 
ovaries  and  two  testicles  in  the  Perca  marina  and 
Labrus  channa,  (Sulla  Generazione  dei  Peschi  et  dei 
Granchi,  Nap.  1787,)  had  been  previously  shewn 
by  Rudolphi  to  depend  upon  his  having  mistaken 
undeveloped  portions  of  the  ovaries  for  testicles. 
(Schweigger's  Skeletlose  Thiere.  s.  204;  and  Ab- 
handlungen.  Konig.  Akad.  der  Wissenschaft  zu 
Berlin,  1825.  p.  48.} 

$  Commerciurn  Litter.  Norim.  1734.    Hebd.  39. 

]|  Pipping,  Vetensk.  Akad.  nya  Handl.  (1800.) 
Bd.  xxi.  s.  33.  tab.  i.  fig.  1.  Leuwenhoeck,  Ex- 
perim.  et  Contempl.  p.  150.  Eph.  Nat.  Cur.  Dec. 
i.  Ann.  i.  obs.  125.  Du  Hamel,  Traite  des  Poissons, 
Part  ii.  p.  130. 

11  Alischer,  Breslau.  Sammlung.  1720,  p.  645 ; 
Morand,  Mem.  de  l'Acad.  des  Sc.  1737.  p.  72. 
Schwalbe,  Commer.  Lit.  Norimb.  1734.  p.  305. 

**  Marchant,  Mem.  de  l'Acad.  des  Sc.  1737.  p. 
12.    Baster,  Opusc.  Subcesiva,  torn.  i.  p.  138. 

+t  Pallas,  Reise  durch  Russe,  &c.  Theil.  ii.  s. 
341. 

ft  Reaumur,  Mem.  de  l'Acad.  1737.  p.  51. 
Starke,  Eph.  Nat.  Cur.  Dec.  iii.  ann.  vii.  and  viii. 
obs.  109. 


one  instance  recorded  by  Bechstein,*  in  a 
chicken  that  had  a  testicle  on  the  right  side  of 
the  body,  and  an  imperfect  reniform  ovary  on 
the  left.  The  external  appearance  of  the  bird 
presented  a  mixture  of  the  characters  of  the  two 
sexes. 

Rudolphi  has  referred  to  a  second  and  more 
ancient  example  of  lateral  hermaphroditism  in 
the  hen,  mentioned  by  Ileide.f  The  case,  en- 
titled by  the  author  "  galli  qui  putabatur  her- 
maphroditus  anatome  rudis,"  is  so  imperfectly 
detailed  as  not  to  be  entitled  to  much  attention. 

We  have  ourselves  been  fortunate  enough  to 
meet  with  two  domestic  fowls  that  presented  in 
their  sexual  organization  examples  of  lateral  her- 
maphroditism. In  the  first  of  these  cases  (fig. 
290)  the  female  sexual  organs  were  placed  on  the 


Fig.  290. 


left  side  of  the  body,  and  the  ovary  (a)  and  ovi- 
duct (b)  were  in  all  respects  apparently  natu- 
rally formed.  On  the  right  side,  a  male  vas 
deferens  (</),  of  about  half  the  normal  length, 

*  Naturgeschichte  der  Voegel,  &c.  Bd.  ii,  s.  1219, 
(1807). 

+  Anatome  Mytuli :  subjecta  est  Centuria  Obser. 
Amster.  1684,  p.  193,  obs.  95. 


698 


HERMAPHRODITISM. 


ran  up  from  the  cloaca  to  opposite  the  origin  of 
the  iliac  vessels  (r),  and  during  this  part  of  its 
course  was  bent  into  those  short  transverse  zig- 
zag folds  which  characterise  the  structure  of  this 
part  in  the  common  cock.  (See  article  Aves, 
vol.  i.  p.  354.)  When  it  reached  the  middle 
third  of  the  kidney  (dd),  it  lost  this  particular 
form,  became  membranous  (e),  and  after  pro- 
ceeding upwards  for  about  an  inch,  in  the  com- 
mon course  of  the  canal,  at  last  disappeared. 
The  convoluted  or  contorted  portion  ran  over  a 
space  of  about  two  and  a  half  inches,  and  if 
unrolled  would  have  extended  three  or  four 
times  that  length.  Its  canal  was  about  the 
usual  size  of  the  same  part  in  the  perfect 
cock,  and  perhaps  at  some  parts  even  more 
dilated.  Its  cavity  was  filled  with  a  whitish 
seminal-looking  albuminous  fluid,  which  at  first 
prevented  a  mercurial  injection  from  readily 
passing  through  it.  There  was  not  any  appa- 
rent vestige  of  a  testicle.  The  fowl  that  was 
the  subject  of  this  malformation  possessed  in 
an  imperfect  degree  the  plumage,  comb,  spurs, 
and  general  appearance  of  the  cock,  and  when 
young  was  considered  to  be  a  male  until  the 
time  it  commenced  to  lay  eggs,  which  it  did 
very  constantly,  except  during  the  moulting 
season,  up  to  the  time  of  its  death.  Its  eggs 
were  remarked  to  be  very  large.  They  had  re- 
peatedly been  tried  to  be  hatched,  but  always 
without  success.  The  bird  itself  was  never  known 
to  incubate.  It  was  peculiar  in  its  habits  in  so 
far  that  in  the  barn-yard  it  did  not  associate  with 
the  other  poultry,  and  at  night  roosted  sepa- 
rately from  them.  It  crowed  regularly,  espe- 
cially in  the  morning,  and  often  attempted  copu- 
lation with  the  hens. 

In  the  second  case,  the  ovaries  and  oviduct 
on  the  left  side  of  the  body  were,  as  in  the 
former  example,  natural  in  themselves ;  but 
in  the  mesometry  of  the  oviduct,  a  tube  of  the 
size  of  the  male  vas  deferens  was  found.  This 
tube,  like  the  normal  vas  deferens,  was  thrown 
into  the  distinctive  angular  folds.  It  ran  for 
about  an  inch  and  a  half  through  the  upper 
portion  of  the  mesometry,  was  blind  at  either 
extremity,  and  admitted  of  being  injected  with 
quicksilver.  On  the  right  side,  there  was  also 
a  male  vas  deferens,  marked  with  the  characte- 
ristic angular  folds.  Thjp  contorted  portion  of 
this  canal  only  stretched  in  this  instarrce'^tq , 
about  an  inch  above  the  cloaca ;  but  the  folds 
were  even  stronger  than  in  the  first  case,  and 
the  tube  itself  was  rather  more  dilated.  Above 
or  anterior  to  this  convoluted  part,  the  tube  be- 
came straight  and  membraneous,  and  ran  up  in 
this  form  for  about  two  inches  in  its  usual 
track  over  the  abdominal  surface  of  the  kidney  ; 
but  there  was  not  at  its  upper  extremity  any 
trace  of  a  testicle.  This  bird  presented  during 
life,  in  a  very  slight  degree  only,  the  appearance 
of  a  cock,  its  comb  and  spurs  being  even  less 
developed  than  in  the  previous  case.  It  shewed 
the  same  solitary  habits  in  the  poultry-yard.  It 
layed  eggs  regularly.  On  three  different  occa- 
sions I  had  a  number  of  them  submitted  to 
incubation,  but  in  none  of  them  was  a  chick 
produced. 


In  the  Quadruped,  Schlump*  has  mentioned 
an  instance  of  lateral  hermaphroditic  malfor- 
mation. In  a  young  calf  he  found  on  the  left 
side,  under  the  kidney,  a  small  testicle  having 
attached  to  it  a  vas  deferens,  which  was  con- 
nected with  the  peritonaeum  towards  the  abdo- 
minal ring  of  the  same  side,  and  there  became 
lost  in  the  cellular  texture  of  the  part.  An  ovary 
and  Fallopian  tube,  with  an  uterus  consisting  of 
a  single  horn  only,  were  connected  to  the  right 
side  of  the  loins  by  a  ligament.  The  neck  of 
the  uterus  lost  itself  in  the  cellular  substance 
beneath  the  rectum,  and  there  was  no  vagina. 
The  external  organs  were  male,  but  imperfectly 
formed.  The  udder  occupied  the  place  of  the 
scrotum. 

In  the  human  subject  several  different  in- 
stances of  sexual  malformation  have  now  been 
met  with  referable  to  the  head  of  lateral  herma- 
phroditism. In  these  cases,  along  with  a  tes- 
ticle on  one  side,  and  an  ovary  on  the  other, 
there  has  generally  co-existed  a  more  or  less  per- 
fectly formed  uterus.  The  external  parts  have 
differed  in  their  sexual  characters,  in  some  in- 
stances being  female,  in  others  male,  and  in 
others  again  of  a  neutral  or  indeterminate  type. 

In  man,  and  in  the  higher  quadrupeds,  we 
have  not  unfrequently  exhibited  to  us  a  slight 
tendency  to  this  unsymmetrical  type  of  sexual 
structure  constituting  true  lateral  hermaphro- 
ditism in  the  testicle  of  one  side  only  des- 
cending, whilst  the  other,  in  consequence  of 
imperfect  development,  remains  within  the 
inguinal  ring.  In  the  single  unsymmetrical 
ovary  of  most  female  birds  and  some  nshes,f 
we  see  a  still  nearer  approach  to  the  state ;  and 
it  is  worthy  of  remark,  that  among  birds  at 
least,  the  single  ovary  is  always  placed  upon  the 
left  side.  In  lateral  hermaphrodites  in  the  hu- 
man subject,  the  left  side  also  appears  to  be  that 
on  which  we  most  frequently  meet  with  the 
female  type  of  the  sexual  organs.  We  shall 
divide  the  following  cases  according  to  the  par- 
ticular sides  which  were  respectively  male  and 
female  in  them. 

1 .  Ovary  on  left  side,and  testes  on  the  right. — 
a.  M.  Sue  met,  in  1746,  with  an  instance  of  late- 
ral hermaphroditism  in  the  human  subject,  in  a 
young  person  of  thirteen  or  fourteen  years  of 
age,  whose  case  was  the  subject  of  a  Thesis 
sustained^  by  M.  Morand.J    Of  the  internal 

*  Archiv.  fuer  die  Thierheilkunde,  Bd.  ii.  Hft.  ii. 
s.  204.  H 

t  In  the  early  embryo  ofbirds,  the  ovaries  are  ori- 
ginally double,  as  pointed  out  by  Emmert,  (see  Reil's 
Archiv  for  1811;)  and  as  was  previously  known 
to  Wolff  and  Hochstetler,  (Anat.  Phil.  torn.  i.  p. 
349.) 

t  De  Hermaphroditis,  Paris,  1749.  This,  ac- 
cording to  Amaud,  (p.  323,)  is  the  same  case  of 
lateral  hermaphroditism  with  that  described  by 
Lecat.  If  so,  the  latter  author,  (probably  from 
drawing  his  description  from  memory,  and  not, 
as  Morand  seems  to  have  done,  from  the  parts 
placed  before  him,)  has  stated  that  along  with 
the  testicle  and  vas  deferens  on  the  one  side,  there 
existed  a  vesicula  seminalis,  and  that  both  sides 
were  provided  with  round  ligaments,  the  one  on  the 
male  side  forming  probably  one  of  the  two  tubes 
described  by  Morand  as  arising  from  the  testicle. 


HERMAPHRODITISM. 


699 


genital  organs,  there  existed  on  the  left  side 
a  very  distinct  ovary,  a  round  ligament  which 
ran  outwards  to  the  groin  of  the  same  side, 
and  a  well-formed  Fallopian  tube  with  its 
usual  fimbriated  extremity.  The  other  extre- 
mity of  the  Fallopian  tube  terminated  in 
the  fundus  of  the  uterus,  which  occupied  its 
usual  situation  between  the  bladder  and  rectum. 
On  the  right  side,  again,  there  was  a  slender 
elongated  testicle,  which  had  moved  forwards 
to  the  corresponding  inguinal  canal,  but  had 
not  proceeded  so  far  as  to  pass  out  of  the  ab- 
dominal cavity.  On  the  superior  part  of  the 
testicle  was  a  body  resembling  the  epididymis, 
and  the  testicle  itself  sent  off  two  tubes,  which 
afterwards  united  into  one  immediately  before 
their  insertion  into  the  uterus.  The  external 
genital  organs  were  those  of  ahypospadic  male, 
and  during  life  the  person  had  been  always 
looked  upon  as  belonging  to  the  male  sex.  The 
perinatal  canal  or  vagina  terminated, between  the 
scrotum  and  root  of  the  imperforate  penis,  in  a 
very  small  opening,  which  was  common  to  it 
and  to  the  meatus  urinarius. 

b.  In  1754,*  a  young  person  of  about  eighteen 
years  of  age  died  in  the  Hotel  Dieu  of  Paris ; 
and  in  dissecting  his  body,  the  anatomist,  Varole, 
found  the  reproductive  organs  malformed  in  the 
following  manner.  On  the  right  side  the 
scrotum  contained  a  testicle,  and  the  vas  defe- 
rens arising  from  it  opened,  not  as  usual  into 
the  neck,  but  into  the  middle  of  the  external 
border  of  the  corresponding  vesicula  seminalis. 
On  the  left  side  the  scrotum  was  empty  ;  and 
internally  on  this  side  there  were  found  an 
ovary,  a  Fallopian  tube  with  its  fimbriated  ex- 
tremity, a  small  oval  uterus  without  a  neck  and 
somewhat  flattened,  and  a  broad  and  round 
ligament,  the  last  of  which  ran  outwards,  and 
was  lost  in  the  cellular  tissue  of  the  left  half  of 
the  scrotum.  The  vesicula  seminalis  on  the 
right,  and  the  imperfect  uterus  on  the  left  side, 
communicated  by  a  canal  of  an  inch  and  a  half 
in  length.  The  external  organs  were  male ;  but 
the  penis  was  very  small,  had  no  corpus  spongi- 
osum, and  was  imperforate  for  half  an  inch  at 
its  anterior  extremity.  The  mamma?  were  as 
large  as  in  women  of  the  same  age.  The  indi- 
vidual had  been  regarded  during  life  as  a  male. 

c.  In  1825  the  late  Professor  Rudolphif  de- 
tailed to  the  Academy  of  Sciences  at  Berlin 
the  case  of  an  infant  who  was  reported  to  have 
died  seven  days  after  birth,  and  whose  sexual 
organs  exhibited  the  following  interesting  in- 
stance of  lateral  hermaphroditic  conformation. 

Meckel  (Reil's  Archiv.  Bd.  xi.  s.  322,)  considers 
Morand's  and  Lecat's  as  two  different  cases,  and 
points  out  that  what  is  described  as  the  male  side 
in  the  one,  was  the  female  in  the  other,  and  vice 
versa.  It  is,  perhaps,  not  unworthy  of  remark,  that 
in  the  coloured  plate  accompanying  the  translation 
of  Morand's  case  by  Gautier,  the  male  and  female 
sides  have  been  reversed  from  an  error  in  the  en- 
graving ;  and  this  circumstance  may  have  contribu- 
ted to  mislead  Lecat  in  his  description,  provided  he 
happened  to  look  to  this  notice  of  the  case. 

*  Mem.  de  la  Soc.  Med.  de  Paris,  torn.  iv.  p. 
342. 

t  Abhandlung.  Konig.  Akad.  dcrWissenscliaft.  zu 
Berlin  fur  1825,  s.  60. 


On  the  left  side  were  discovered  an  ovary 
(fig.  291,  a),  without  a  distinct  broad  ligament, 


Fig.  291. 


Uterus  (c)  turned  downwards  and  forwards  to  show 
its  posterior  surface  and  connections,  Sfc. 

and  a  Fallopian  tube  (b),  which  communi- 
cated with  the  superior  and  left  portion  of  an 
uterus  (c).    The  left  side 
of  the  scrotum  (fig.  292,       Fig.  292. 
a),  was  empty;  the  right 
(6)  contained  a  testicle 
(fig. 291, d)  furnished  with 
an  epididymis  (e)  and  tor- 
tuous vas  deferens  (./'). 
Below  the  uterus  there 
was  a  hard  flattened  ovoid 
body  (fig.  291,  g,  and 
fig.  293,  b),  which,  when 
divided    was    found  to 
consist  of  a  cavity  with 
thick  parietes,  and  was 
considered  by  Rudolphi      External  organs. 
as  the  prostate  gland  in  a  rudimentary  state. 


Fig.  293. 


Os  uteri,  va/jina, 
prostate,  and  vas 
deferens. 


The  mouth  of  the  uterus 
(fig.  293,  a)  terminated  be- 
low in  the  parietes  of  this 
ovoid  body,  and  on  the 
right  the  vas  deferens  (d) 
penetrated  into  its  sub- 
stance, but  without  open- 
ing into  its  cavity.  At  the 
inferior  part  of  the  uterus 
there  was  a  true  vagina 
(fig.  293,  c),  which  termi- 
nated in  a  cul-de-sac.  The 
anus,  rectum,  and  other 
organs  were  natural.  The 
external  sexual  parts  were 
male,  but  the  penis  was  divided  inferiorly 
(fig.  292,  c).  The  testicle  and  ovary  were  sup- 
plied with  the  two  usual  spermatic  arteries 
(fig.29l,hh). 

d.  Under  the  present  section  of  lateral  herma- 
phroditism, we  may  also,  according  to  Mayer's 
report,  include  the  celebrated  case  of  Marie 
Derrier,  or  Charles  Doerge.*  This  person  was 
baptised  and  brought  up  as  a  female,  but  at 
forty  years  of  age  was  persuaded  to  change  his 
name  and  dress  to  those  of  a  man.  We  have 
already  alluded  to  the  great  diversity  of  opinion 
which  was  entertained  by  the  medical  men  of 

*  Gazette  Med.  de  Paris  (1836),  no.  39.  Lancet, 
v.  i.  for  1836-7,  p.  140 ;  or  London  Medical  Ga- 
zette for  October  29,  1836. 


700 


HERMAPHRODITISM. 


Europe  in  regard  to  the  true  sex  of  this  indivi- 
dual. Even  the  different  parts  of  his  body  were 
at  one  time  referred  to  the  male  type,  and  at 
another  time,  and  by  other  persons,  to  the  fe- 
male. The  pelvis  was  the  only  part  that  was 
generally  considered  as  decidedly  female,  yet 
the  inspection  of  the  body  after  death  by  Pro- 
fessor Mayer  shewed  that  even  in  this  respect 
all  were  in  error. 

Of  the  female  sexual  organs  there  existed  an 
uterus,  vagina,  two  Fallopian  tubes,  and  an 
ovary  ;  and  of  the  male,  a  testicle,  and  prostate 
gland  and  penis.  The  uterus  was  placed  in 
its  normal  situation  between  the  urinary  bladder 
and  rectum,  but  with  its  fundus  directed  in  some 
degree  to  the  left.  The  organ  was  extremely 
narrow,  and  two  and  a  half  inches  in  length. 
The  cavity  of  its  cervix  presented  on  its  inner 
surface  some  slight  folds,  but  would  scarcely 
admit  a  quill ;  the  cavity  of  its  fundus  was 
nearly  half  an  inch  across.  The  small  canals  of 
two  Fallopian  tubes  opened  into  the  fundus 
uteri.  Their  abdominal  extremities  were  shut, 
but  the  corpora  fimbriata  were  present.  Near 
the  extremity  of  the  right  Fallopian  tube,  which 
was  four  inches  and  four  lines  in  length,  a  small 
flattened  almond-shaped  body  was  placed,  which 
on  examination  proved  to  be  distinctly  a  testi- 
cle. It  was  completely  enveloped  in  perito- 
naeum, and  received  a  cord  composed  of  muscu- 
lar fibres,  and  of  a  spermatic  vein  and  artery. 
Its  internal  structure  was  yellow  and  filamen- 
tous, like  that  of  the  testicle,  and  its  seminiferous 
tubes  could  be  easily  separated.  The  left  Fallo- 
pian tube  was  an  inch  shorter  than  the  right ; 
and  a  little  outside  and  behind  its  abdominal 
extremity  another  small  flattened  body  was 
found  inclosed  in  the  peritonaeum.  It  resembled 
an  ovary  rather  than  a  testicle.  Its  tissue  was 
composed  of  small  granules  conglomerated 
together.  The  penis  was  two  inches  and  nine 
lines  in  length,  and  was  for  the  greater  part 
concealed  underneath  the  mons  veneris.  During 
life  it  was  capable  of  erection,  and  was  then 
elongated  to  more  than  three  inches.  The  pre- 
puce covered  only  half  the  glans.  There  was 
not  any  corpus  spongiosum.  A  fossa  or  groove, 
representing  an  urethral  canal  divided  inferiorly, 
ran  along  the  under  surface  of  the  penis.  The 
two  folds  of  skin  forming  the  sides  of  the 
groove  separated  from  each  other  posteriorly, 
and  might  be  compared  to  nymphs.  Towards 
the  root  of  the  penis,  by  uniting  inferiorly  with 
a  puckering  of  the  skin  of  the  labia  majora  or 
divided  halves  of  the  scrotum,  they  formed  a 
circular  orifice  not  larger  than  a  quill,  having 
some  bodies,  supposed  to  be  vestiges  of  the  ca- 
runculffi  myrtiformes,  at  its  lower  edge,  and  lead- 
ing to  a  short  vestibule,  or  common  canal,  into 
which  the  urethra,  surrounded  by  a  firm  but 
small  prostate,  entered  from  above,  and  the  va- 
gina, encircled  at  its  entrance  by  a  vascular 
ring  of  varicose  veins,  opened  from  below.  The 
vagina  was  two  inches  and  eight  lines  in  length, 
and  only  ten  lines  at  its  greatest  breadth.  Its 
inner  surface  was  somewhat  wrinkled  an- 
teriorly, but  smooth  behind.  It  terminated 
above  in  a  kind  of  spongy  isthmus  representing 
the  blind  orifice  of  the  uterus,  and  from  four  to 


six  lines  in  length.  The  diameters  and  form  of 
the  pelvis  were,  on  dissection,  found  to  be  most 
evidently  masculine. 

The  general  character  of  Doerge  was  a  mix- 
ture of  the  male  and  female  type.  When  be- 
tween twenty  and  thirty,  he  had  been  examined 
by  different  medical  men  inGermany,  France,  and 
England,  and,  as  we  have  already  mentioned, 
the  most  contradictory  opinions  were  offered 
upon  his  real  sex.  The  breasts  were  not 
much  developed,  and  there  was  no  distinct 
mammary  glandular  structure.  His  stature  was 
small  (five  feet).  As  he  had  advanced  in 
age,  his  voice  had  become  more  firm  and 
grave,  and  a  slight  trace  of  beard  had  ap- 
peared ;  but  his  head  and  face  presented  the 
aspect  of  that  of  an  old  woman.  His  neck  was 
short,  and  the  thyroid  cartilage  did  not  project 
much  :  his  chest  was  fat  and  full.  During  the 
last  few  years  of  his  life  he  was  subject  to 
epistaxis  and  haemorrhoids,  but  did  not  present 
any  trace  of  sanguineous  discharge  from  the 
genital  organs, — a  phenomenon  which  was 
alleged  to  have  manifested  itself  three  limes 
during  his  twentieth  year. 

The  right  hemispheres  of  the  cerebrum  and 
cerebellum,  particularly  that  of  the  latter,  were 
smaller  and  less  developed  than  the  left,  and  the 
left  side  of  the  occiput  was  externally  more 
prominent  than  the  right.  He  is  stated  by 
Professor  Mayer  to  have  shewn  a  certain  predi- 
lection for  females,  without,  however,  feeling 
any  sexual  desire. 

2.  Testicle  on  the  left,  and  ovary  on  the 
right  side. — An  instance  of  malformation  of  the 
reproductive  organs  minutely  described  by 
Maret,*  and  which  is  in  all  its  more  essential 
anatomical  points  an  example  of  lateral  herma- 
phroditism, may  be  included  under  this  head. 

a.  The  subject  of  the  case  (Hubert  Jean 
Pierre)  died  in  the  hospital  at  Dijon  in  1767, 
at  the  age  of  seventeen.  On  the  left  side  a 
perfect  testicle  was  discovered  with  its  usual 
spermatic  vessels,  vas  deferens,  and  vesicula 
seminalis,  all  occupying  the  natural  situation 
in  which  they  are  placed  in  the  male  adult. 
The  vesicula  seminalis  contained  a  fluid  of  the 
colour  and  consistence  of  semen.  On  the  right 
side  an  oblong  cystic  tumour  was  found  lying  in 
the  iliac  fossa,  and  stretching  outwards  into  the 
inguinal  region.  On  opening  it  a  quantity  of 
reddish  limpid  fluid  escaped,  and  then  the  solid 
contents  of  the  tumour  were  seen  to  consist  of  a 
somewhat  flattened  body,  that  gave  off  from  the 
upper  part  from  its  right  side  a  short  Fallopian 
tube ;  and  at  the  fimbriated  extremity  of  this 
tube  an  ovary  of  the  natural  size,  consistence, 
and  figure,  was  situated.  The  roundish  shaped 
body  to  which  the  tube  was  attached  was  about 
an  inch  and  a  half  in  its  greatest,  and  an  inch  in 
its  smallest  diameter.  It  contained  in  its 
centre  a  small  cavity  continuous  with  that  of 
the  tube, — a  circumstance,  which,  along  with  the 
structure  of  its  walls,  left  little  doubt  that  the 
body  itself  was  an  imperfectly  formed  uterus. 
No  other  opening  except  that  of  the  tube  could 
be  traced  into  its  cavity.    Its  external  surface 

*  Mem.  de  1'  Acad,  de  Dijon,  t.  ii.  p.  157. 


HERMAPHRODITISM. 


701 


was  attached  to  the  ovary  by  a  kind  of  ligament. 
On  this  same  side  of  the  body  (the  right)  there 
existed  also  a  vesicula  sermnalis,  but  smaller 
and  more  shrivelled  than  that  on  the  left.  It 
gave  off  a  vas  deferens,  which  became  gradu- 
ally smaller  as  it  was  traced  backwards,  and  at 
last  disappeared  altogether  without  being  con- 
nected with  any  structure  resembling  a  testi- 
cle. In  regard  to  the  external  organs  of 
generation,  the  penis  was  four  inches  long 
and  imperforate,  but  in  all  other  respects  per- 
fectly formed.  It  possessed  a  corpus  spongi- 
osum, which  does  not  exist  in  the  female 
clitoris.  On  raising  the  penis,  it  was  observed 
to  cover  a  large  fissure,  the  sides  of  which 
resembled  the  labia  of  a  female.  In  the  left 
labium  or  left  half  of  the  scrotum  the  testicle 
already  alluded  to  was  placed,  but  there  was 
none  in  the  right.  When  the  labia  were 
separated,  two  red  spongy  bodies  were  seen, 
resembling  the  nymphse  in  appearance,  and 
seemingly  consisting  of  the  sides  of  the  split 
urethra.  Between  these  bodies  and  at  their 
upper  part,  the  urethra  opened  as  in  the  female  ; 
while  below  there  was  a  very  narrow  aperture 
covered  by  a  semilunar  membrane,  and  pre- 
senting on  one  side  of  its  entrance  a  small  ex- 
crescence somewhat  resembling  in  figure  a 
caruncula  myrtiformis.  This  orifice  led  into 
a  membranous  canal  or  cul-de-sac  an  inch  in 
depth,  and  half  an  inch  in  diameter.  On  the 
lower  part  of  this  canal  the  verumontanum  and 
orifices  of  the  seminal  ducts  of  both  sides  were 
discovered. 

During  life  Pierre  had  been  considered  a 
male,  but  was  not  known  to  have  shown 
any  partiality  for  the  female  sex.  His  counte- 
nance was  more  delicate  than  what  we  ordi- 
narily see  in  the  male  sex.  There  was  no 
beard  on  the  face  ;  the  larynx  was  not  enlarged 
as  in  man  ;  and  the  raamnis,  each  of  which 
was  furnished  with  a  very  large  areola,  were  of 
a  moderate  size  and  roundish  form.  The  con- 
figuration of  the  lower  part  of  the  body  was 
more  decidedly  masculine,  and  there  was 
none  of  that  enlargement  of  the  buttocks  and 
projection  of  the  thighs,  from  the  increased 
width  of  the  pelvis,  which  is  observable  in 
young  females. 

In  this  case  we  have  on  the  left  side  of  the 
body  male  sexual  organs,  consisting  of  a  per- 
fect testicle,  vas  deferens, and  vesicula  seminalis. 
On  the  right  side,  again,  we  have  a  female  ovary 
and  Fallopian  tube  with  a  rudimentary  uterus, 
together  with  an  imperfect  male  vesicula  semi- 
nalis and  vas  deferens. 

Arnaud  mentions  a  very  imperfect  form 
of  lateral  hermaphroditism  as  having  been  re- 
cognised by  M.  Boudou,  surgeon  to  the  Hotel- 
Dieu  of  Paris,  on  the  person  of  a  monk  who 
died  in  that  hospital  in  1726.  The  external 
genital  parts  were  those  of  a  hypospadic  male. 
In  one  of  the  halves  of  the  scrotum  a  testicle 
was  found  ;  the  other  was  empty.  The  seminal 
canals  and  vesicula?  seminales  on  the  side  on 
which  the  perfect  testicle  existed  were  natural 
in  their  course  and  situation.  Those  of  the 
opposite  side  lost   themselves   between  the 


bladder  and  rectum  in  a  small  body,  which,  in 
M.  Boudou's  opinion,  was  a  shrunk  uterus.* 

Among  the  preceding  cases  of  lateral  herma- 
phroditism in  the  human  subject,  there  are  four 
in  which  the  left  side,  and  one  only  in  which 
the  right  was  the  female.  In  the  last  instance 
quoted  from  Boudou  the  respective  sides  on 
which  the  male  and  female  organs  were  placed 
are  not  stated  by  Arnaud. 

B.  Transverse  hermaphroditism.— In  the 
variety  of  hermaphroditic  malformation  which 
we  have  last  considered,  we  have  found  upon 
the  same  individual  the  reproductive  organs  of 
one  side  disagreeing  in  their  sexual  type  from 
those  of  the  other.  In  the  present  division  we 
have  a  similar  sexual  antagonism  following  a 
different  direction  ;  for  supposing  the  internal 
sexual  apparatus  to  be  divided  from  the 
external  by  a  transverse  line,  we  have,  in  trans- 
verse hermaphroditism,  on  each  side  of  this 
partition,  organs  of  an  opposite  sexual  type  : 
in  other  words,  the  organs  of  reproduction 
(in  the  more  correct  sense  of  the  word)  or  the 
internal  sexual  organs  do  not,  in  the  present 
species  of  hermaphroditism,  correspond  in  type 
with  the  organs  of  copulation,  or  the  external 
sexual  parts, — a  circumstance  the  occasional 
occurrence  of  which  tends  to  shew  that  these 
two  portions  of  the  generative  apparatus  are  in 
some  degree  independent  of  one  another  in 
their  normal  development  and  existence,  and 
consequently  also  in  their  abnormal  formations. 

Transverse  hermaphroditism  varies  in  its 
character  according  to  the  relative  positions 
occupied  by  the  co-existing  male  and  female 
oigans ;  the  external  organs,  or  all  those  ex- 
terior to  the  supposed  transverse  line,  being 
sometimes  female,  and  the  internal  male,  and 
vice  versa. 

1.  Transverse  hermaphroditism  with  the 
external  sexual  organs  of  the  female  type. — In 
the  cases  included  under  this  division,  the  ex- 
ternal genital  oigans  consist  of  a  clitoris, 
vagina,  and  uterus  ;  the  uterus  is  often  rudi- 
mentary, and  sometimes  altogether  absent  and 
replaced  by  the  male  vesicula?  seminales.  The 
male  internal  organs  are  the  testicles,  generally 
small  and  imperfectly  developed,  and  placed 
either  within  or  without  the  abdomen,  with 
vasa  deferentia  terminating  in  the  uterus  and 
vagina. 

This  variety  of  sexual  malformation  has  been 
repeatedly  observed  among  our  domestic 
quadrupeds,  particularly  among  black  cattle. 
Mr.  John  Hunter,  in  an  essay  read  before  the 
Royal  Society  in  1779,  and  published  in  their 
Transactions^  and  in  his  Observations  on  the 
Animal  Economy,  shewed  that,  (as  had  been 
long  known  among  agriculturists,)  when  among 
black  cattle  the  cow  brings  forth  twin  calves, 
one  of  them  a  male,  and  the  other  apparently 
a  female,  the  male  is  a  perfect  bull  calf,  but  the 
female,  while  it  has  all  the  external  marks  of 
a  cow-calf,  as  the  teats  and  udder,  is  still,  with 
a  few  exceptions,  imperfectly  formed  in  its 

*  Arnaud,  loc.  cit.  p.  283. 
f  Vol.  lxix. 


702 


HERMAPHRODITISM. 


internal  sexual  organs,  and  very  generally  pre- 
sents a  mixture  of  the  organs  of  the  two  sexes  in 
various  degrees.  Such  hermaphroditic  twin 
cattle  have  long  been  distinguished  in  this 
country  under  the  name  of  free-martins.  In 
some  exceptional  cases  only  have  they  been 
observed  capable  of  breeding;  and  generally 
they  shew  no  sexual  desire  for  the  bull,  or  the 
bull  for  them.  In  appearance  they  resemble 
the  ox  or  spayed  heifer,  and  have  a  similar,  or 
still  greater  disposition  to  become  fat  under 
the  use  of  good  food. 

In  the  paper  to  which  we  have  referred,  Mr. 
Hunter  has  described  the  dissection  of  three 
free-martins  :  and  one  of  these  seems  to  belong 
to  our  present  division  of  female  transverse 
hermaphroditism.  The  clitoris  and  external 
parts  appear  to  have  been  strictly  of  the  female 
type,  and  there  was  a  small  udder  with  four 
teats.  The  vagina  terminated  in  a  blind  end  a 
little  beyond  the  opening  of  the  urethra,  and 
from  this  point  the  vagina  and  uterus  were  im- 
pervious. The  uterus  at  its  superior  part 
divided  into  two  horns,  and  at  the  termi- 
nations of  these  horns,  not  ovaria,  but  bodies 
resembling  the  male  testicles  were  found.  These 
bodies  had  not  a  perfect  internal  structure  like 
that  of  testicles,  but  resembled  these  organs  in 
so  far  that,  1st,  they  were  nearly  as  large  as 
the  male  testes,  and  much  larger  than  the 
female  ovaries ;  2nd,  they  were  supplied  with 
tortuous  spermatic  arteries  like  those  of  the  bull 
or  rigdil ;  and  3d,  cremaster  muscles  passed 
up  to  them,  as  in  rigdils,  from  the  abdominal 
rings.  There  were  two  small  vesicular  semi- 
nales  placed  behind  between  the  bladder  and 
uterus,  with  their  ducts  opening  into  the 
vagina.  Nothing,  according  to  Mr.  Hunter, 
similar  to  the  vasa  deferentia  was  present; 
but  Guilt  is  inclined  to  believe  that  the  parts 
which  Mr.  Hunter  has  described  as  the  horns 
of  the  uterus  were  really  the  deferent  vessels. 

Professor  Gurlt*  has  himself  given,  from  a 
preparation  in  the  Museum  of  the  Berlin 
Veterinary  School,  the  accompanying  sketch  of 
the  malformed  sexual  organs  of  a  five-year  old 
free-martin,  (fig.  294,)  which  presents  to  us  an 
illustration  of  Mr.  Hunter's  supposed  mistake, 
at  the  same  time  that  it  affords  a  well-marked 
example  of  transverse  hermaphroditism.  The 
detail  of  the  anatomical  peculiarities  of  the 
case  has  been  unfortunately  omitted  by  the 
author,but  from  the  short  explanations  appended 
to  the  drawing,  it  appears  that  the  clitoris  («) 
and  external  pudenda  (6)  were  perfectly 
feminine,  and  that  the  vagina,  short  and  funnel- 
shaped,  terminated  at  its  superior  contracted 
extremity  in  two  vasa  deferentia  (ccc),  which 
were  carried  upwards  in  a  duplicature  of  peri- 
tonaeum (d  d)  resembling  the  broad  ligament, 
until  they  joined  the  unrolled  and  lengthened 
epididymes  (e  e)  of  two  small  testicles  (J[f) 
placed  in  the  position  of  the  ovaries.  Near  the 
junction  of  the  vagina  and  vasa  deferentia 
bodies  resembling  the  male  vesicular  seminales 

*  Lehrbuch  der  Pathol.  Anat.  d.  Sang.  Th.  Bd. 
ii.  S.  186. 


Fig.  294. 


(gg)and  Cowper's  glands  (A  A)  were  situated, 
and  the  urethral  canal  (i)  opened  into  the 
vagina  and  was  shorter  than  it  usually  is  in  the 
cow. 

We  have  found  upon  a  free-martin  cow  a 
state  of  the  sexual  apparatus  very  much  re- 
sembling that  figured  in  the  above  case  by 
Professor  Gurlt.  The  two  vasa  deferentia,  as 
they  ran  in  the  duplicature  of  the  peritonaeum, 
had  very  much  the  appearance  and  shape  of  an 
imperfectly  developed  uterus.  The  vesiculae 
seminales  were  large  ;  the  vasa  deferentia  were 
quite  impervious  throughout  their  whole  course; 
and  the  bodies  placed  at  their  abdominal  ex- 
tremities were  large,  but  of  so  indeterminate  a 
structure  as  not  to  enable  us  to  pronounce  them 
to  be  either  true  testicles  or  ovaries. 

M.  Geoffroy  St.  Hilaire  published  in  1834 
a  very  distinct  case  of  an  hermaphroditic  goat 
which  had  two  male  testicles  and  epididymes 
with  a  two-horned  uterus  and  female  external 
parts.*  M.  Isidore  St.  Hilairef  mentions  a 
nearly  analogous  case  in  the  same  animal, 
and  quotes  a  third  from  Bomare  which  was  ob- 
served upon  a  deer.J 

*  Nouv.  Ann.  du  Museum  d'Hist.  Nat.  t.  ii.  p. 
141. 

t  Histoiredes  Anomalies,  t.  ii.  p.  128. 
}  Journ.  de  Phys.  t.  vi.  p.  501. 


HERMAPHRODITISM. 


To  the  present  division  of  transverse  herma- 
phroditic malformation  with  external  female  and 
internal  male  organs,  we  may  probably  also 
refer  the  case  of  the  hermaphrodite  dog  de- 
tailed by  Sir  E.  Home,*  and  three  instances  in 
the  sheep  described  by  Ruysch,f  Herholdt,J 
and  Gurlt.§  In  all  these  instances  imperfectly 
developed  testicles  were  situated  either  within 
the  abdomen  or  without  it  upon  the  udder,  at 
the  same  time  that  the  external  parts  exhibited 
in  a  more  or  less  marked  degree  the  peculiarities 
of  the  female  sex ;  the  vagina  was,  however,  nar- 
rower, and  the  clitoris  more  developed  than  in 
the  perfectly  formed  female ;  and  in  the  dog 
mentioned  by  Home,  this  latter  organ  was  very 
large,  being  three  quarters  of  an  inch  long,  and 
half  an  inch  broad,  but  still  it  could  not  pro- 
perly be  considered  as  an  imperfect  penis,  since 
the  bone,  which  forms  the  distinguishing  mark 
of  that  organ  in  the  dog,  was  wanting. 

Few  well-marked  instances  of  transverse 
hermaphroditism  with  external  female  organs 
have  been  hitherto  described  as  observed  in  the 
human  subject,  unless  we  regard  as  an  approach 
to  it  the  numerous  cases,  already  referred  to,  of 
spurious  hermaphroditic  malformation  in  the 
male  from  hypospadic  division  of  the  urethra, 
scrotum,  and  perinaeum. 

a.  In  his  essay  on  hermaphroditism,  how- 
ever, Steghlehner||  has  detailed  at  great  length 
the  particulars  of  a  case  belonging  to  the  present 
variety,  which  he  met  with  on  the  body  of  a 
woman  who  died  of  phthisis  at  the  age  of 
twenty-three.  The  external  sexual  organs  were 
all  of  the  female  type  and  in  general  well 
formed,  though  the  clitoris  and  nymphae  were 
perhaps  smaller  than  natural,  and  the  orificium 
vaginae  was  rather  contracted  and  half  shut  up 
by  a  hymen.  The  fossa  navicularis  was  very 
distinct,  and  the  vagina  normally  situated,  but 
extremely  short  and  narrow.  Its  internal  sur- 
face presented  an  appearance  of  transverse  and 
longitudinal  rugae,  but  its  upper  extremity 
formed  a  blind  sac,  and  no  traces  could  be 
found  beyond  it  of  the  uterus,  nor  indeed  any 
vestiges  whatever  of  the  other  internal  female 
organs,  the  ovaries  and  Fallopian  tubes.  On 
more  minute  examination  a  testicle  with  its 
spermatic  cord  was  found  in  each  inguinal 
region,  placed  outside  the  external  ring,  and 
surrounded  with  their  cremaster  muscles  and 
vaginal  coats.  The  testicles  were  flaccid  and 
small,  but  their  internal  structure  and  that  of 
their  epididymes  was  natural ;  and  the  slender 
pervious  vasa  deferentia  arising  from  them 
entered  the  abdomen,  descended  into  the  pelvis, 
and  were  joined  behind  the  urinary  bladder  by 
two  vesicula?  seminales  of  considerable  size. 
Their  common  ejaculatory  ducts  opened  into 
the  vagina.  The  form  of  the  thorax  and  pelvis, 
and  of  the  body  in  general,  was  feminine ;  and 

*  Phil.  Trans,  for  1795,  p.  157.  Comp.  Anat. 
iii.  323. 

t  Thesaur.  Anat.  viii.  n.  c.  iii.  tab.  115 
t  Viborg's  Sammlungs  fuer  Thierartze  (1797.) 
s.  25. 

§  Lehrbuch,  &c.  Bd.  ii.  s.  186.  tab.  ix.  2.  and 
xxii.  s.  2, 

||  Tract,  de  Hermaphr.  natura,  p.  120. 


the  mammae  and  nipples  were  well  developed, 
but  the  larynx  was  rather  more  protuberant  than 
in  females,  and  the  voice  approached  in  tone 
to  that  of  a  man.  There  had  never  been  any 
menstrual  discharge,  but  the  periodical  moli- 
mina  indicative  of  its  appearance  were  said  to 
have  been  observed  regularly.  There  were 
some  haemorrhoidal  tumours  situated  around 
the  anus. 

b.  If  possible  a  still  more  perfect  example 
of  the  present  variety  of  transverse  hermaphro- 
ditism in  the  human  subject  has  lately  been 
observed  at  Naples.  The  malformation  occurred 
in  the  person  of  an  individual  Maria  E.  Arsano, 
who  died  at  the  age  of  eighty  in  one  of  the 
pauper  charities  at  Naples,  and  who  had  passed 
through  life  as  a  female  and  been  married  as 
such.  No  suspicion  of  the  malformation 
existed  during  life,  and  it  was  only  at  first 
accidentally  discovered  in  preparing  the  dead 
body  for  demonstration  in  the  anatomical 
theatre  of  Professor  Ricco,  who  afterwards 
carefully  dissected  the  malformed  parts  in  com- 
pany with  Professors  Sorrentino  and  Grosetti. 
We  have  taken  the  following  account  and 
sketches  from  Ricco's  published  description  of 
the  case.* 

The  external  organs  of  generation  were  those 
of  the  female  in  their  natural  or  normal  state, 
consisting  of  the  mons  veneris  with  a  scanty 
quantity  of  hair  (fig.  295,  a )  ;  of  the  labia  ex- 

Fig.  295. 


terna  (fig.  295  &  296,  b  b )  naturally  formed,  and 
the  nymphae  (fig.  295  &  296,  d  d) ;  of  the 
clitoris  (fig.  295  &  296,  c ),  which  was  perfectly 
imperforate,  and  of  the  ordinary  size  of  the 
same  organ  in  the  adult  female  ;  of  the  orifice 
of  the  urethra  (fig.  295  &  296,  e )  situated  be- 
low the  clitoris ;  and  of  the  os  vaginas  (fig. 
295  &  296,  f),  which  was  of  the  usual  size  and 
diameter.  Altogether  the  aperture  of  the  vulva 
was  natural.  The  canal  of  the  urethra  was 
of  the  usual  length,  as  seen  at  u  in  the  section 

*  Cenno  Storico  su  di  un  Neutro-Uomo,  p.  5,  7. 


HERMAPHRODITISM. 


of  the  pelvis  represented  in  fig.  296,  in  which 
s  marks  the  divided  symphysis  pubis,  and  p  the 

Fig.  296. 


peritonaeum.  The  os  vaginae  shewed  no  vestiges 
of  the  membrane  of  the  hymen,  or,  in  other 
words,  was  without  carunculae  myrtiformes. 
The  canal  of  the  vagina  (fig.  296,  v )  was  about 
two  inches  long,  but  without  ruga?,  and  it  ter- 
minated internally  in  a  completely  blind  extre- 
mity or  cul-de-sac.  The  uterus  was  entirely 
wanting,  as  were  also  the  Fallopian  tubes  and 
uterine  ligaments. 

The  internal  organs  of  reproduction  were, 
on  the  other  hand,  completely  male.  The  two 
testicles  (fig.  295,  g  g)  were  situated  in  the 
region  of  the  pubis,  and  were  scarcely  clear  of 
the  inguinal  rings.  They  were  of  the  usual 
ovoid  figure,  and  natural  in  size.  They  had 
internally  the  structure  of  the  tubuli  seminiferi, 
but  it  was  not  well  developed.  The  spermatic 
cords  were  quite  normal  both  in  regard  to  their 
composition  and  the  origin  and  course  of  their 
bloodvessels.  The  right  spermatic  artery  (fig. 
295,  1)  arose,  as  usual,  from  the  renal,  and 
the  corresponding  vein  (?«),  after  forming  the 
pampiniform  plexus  (A),  opened  into  the  vena 
cava  inferior ;  while  on  the  left  side  the  artery 
(/)  arose  from  the  aorta,  and  the  vein  (in)  ter- 
minated in  the  left  emulgent.  The  epididymes 
of  the  testes  were  also  of  the  usual  vermiform 
figure,  and  the  corresponding  vasa  deferentia 
(fig.  295  &  296  h  h )  coursed  towards  their  vesi- 
culae  seminales  (fig.  296,  j),  and  terminated  in 
an  attenuated  membranous  expansion  without 
any  external  aperture  or  ducti  ejaculatorii. 
The  vesicula?  seminales  (see  the  left  one  j  in 
fig.  296)  were  placed  between  the  urinary  blad- 
der (o)  and  rectum  (r) ;  they  were  smaller  and 
more  shrunk  than  those  of  the  adult  male, 
though  certainly  they  preserved  their  naturally 
oblong  form.  Their  internal  hollow  or  tubular 
structure  was  indistinct.  The  prostate  gland 
was  not  present.  The  urinary  bladder  (o)  and 
ureters  (n  n),  the  rectum  (r),  and  the  other 
intestinal  viscera,  with  the  abdominal  blood- 
vessels (s,  the  aorta,  f,  the  vena  cava,  fig.  295) 
seem  to  have  been  all  quite  natural. 

The  head  of  the  above  individual  was  of  the 
usual  size,  the  neck  long,  and  the  stature 
ordinary.    The  periphery  of  the  thorax  was  so 


expanded  as  almost  to  equal  that  of  the  male, 
notwithstanding  the  presence  of  well  pro- 
nounced mammas.  The  face,  although  entirely 
free  from  hair,  had  yet  neither  the  expression 
of  that  of  a  female  nor  of  a  male,  but  shewed 
more  of  that  mixed  character  which  is  seen  in 
the  eunuch.  The  pelvis  was  altogether  that  of 
a  male  in  its  form  and  dimensions,  and  the 
limbs  were  perfectly  masculine.  According  to 
information  collected  after  death,  the  voice  was 
deep,  and  the  temperament  strong  and  firm. 
Though  there  was  never  any  menstruation,  yet, 
from  being  constantly  employed  in  domestic 
occupation,  the  mental  character  was  feminine, 
and  die  married  state  had  been  willingly  entered 
into. 

2.  Transverse  hermaphroditism  with  the  ex- 
ternal sexual  organs  of  the  male  type. — The 
male  organs  that  are  present  consist  of  the 
penis,  which  is  provided  with  a  regular  formed 
prepuce,  glans,  corpora  cavernosa,  and  corpus 
spongiosum,  with  the  urethra  perforating  it, 
and  of  the  prostate  gland,  verumontanum,  &c. 
The  co-existing  female  organs  are  the  ovaries, 
the  Fallopian  tubes  with  their  infundibula,  and 
the  uterus. 

We  are  not  aware  of  any  recorded  instances 
of  this  variety  of  hermaphroditic  malformation 
among  the  lower  animals.  We  have  already, 
under  the  head  of  spurious  hermaphroditism 
in  the  female  from  enlargement  of  the  clitoris, 
&c,  mentioned  several  cases,  in  which,  from 
excessive  developement,  the  external  organs  in 
women  had  assumed  some  of  the  characters  of 
the  corresponding  parts  in  man ;  but  the  two 
following  cases  described  by  Professors  Esch- 
richt  of  Copenhagen,  and  Bouillaud  of  Paris, 
present  instances  of  malformation  in  which  the 
more  exterior  sexual  organs  were  all  formed 
upon  the  male,  and  the  internal  upon  the 
female  type. 

a.  The  subject  of  the  case  described  by 
Eschricht*  was  a  twin  child  that  died  verj 
shortly  after  birth,  and  in  whom  the  external 
sexual  organs  were  of  the  male  type,  and  the 
internal  female.  The  penis  (fig.  297,  a )  and 
scrotum  (b)  were  well  developed,  but  the  usual 
raphe  seen  upon  the  latter  was  absent.  The 
urethral  canal  of  the  glans  and  body  of  the 
penis  was  pervious  throughout,  and  admitted 
of  a  sound  being  easily  passed  into  the  bladder. 
The  glans  was  remarkably  thin  and  slender. 
The  prepuce  could  be  easily  pushed  back.  No 
testicles  could  be  felt  in  the  scrotum,  and  in- 
ternally there  was  an  uterus  with  Fallopian 
tubes  and  ovaries.  The  uterus  (c)  was  about 
an  inch  in  length,  and  had  the  general  form 
presented  by  this  organ  in  female  infants.  It 
contained  a  cavity  marked  with  ruga;,  but  had 
no  orifice  inferiorly,  nor  any  vagina  attached 
to  it.  Its  blind  or  imperforate  neck  was  firmly 
attached  to  the  posterior  walls  of  the  urinary 
bladder  (g),  while  its  fundus  was  directed  very 
obliquely  downwards  and  over  to  the  left  side. 
From  the  left  side  of  the  fundus  of  the  uterus 
a  twisted  Fallopian  tube  (d)  proceeded,  having 

*  Muller's  Archiv  fuer  Anatomie,  &c.  1836, 
Heft  ii. 


HERMAPHRODITISM. 


705 


Fig.  297. 


well  developed  fimbriae  (e)  at  its  abdominal 
extremity,  and  the  broad  ligament  or  fold  of 
peritonaeum  along  which  it  ran  contained  an 
oblong  soft  body  (i),  (which  Eschricht  considered 
as  distinctly  an  ovary,)  ajid  a  round  ligament 
that  took  its  course  through  the  inguinal  canal 
of  the  same  side.  On  the  right  side  an  ovary 
(k)  and  Fallopian  tube  (J')  were  likewise  dis- 
covered, but  they  were  displaced  and  separated 
from  the  body  of  the  uterus.  The  ovary  lay  in 
the  iliac  region,  and  above  it  and  towards  its 
outer  side  was  placed  the  fimbriated  extremity 
of  the  corresponding  Fallopian  tube.  The  tube 
presented  towards  this  extremity  a  vesicular 
swelling  of  the  size  of  a  small  pea,  which 
admitted  of  being  inflated  and  filled  with 
quicksilver  through  a  small  opening  between 
the  fimbriae.  Below  this  it  was  impervious, 
and  apparently  diverged  off  into  two  prolonga- 
tions, one  of  which  (the  round  ligament)  passed 
down  into  the  inguinal  canal,  and  the  other 
crossed  over  with  a  fold  of  peritonseum  to  where 
the  rectum  and  urinary  bladder  were  preter- 
naturally  connected  together.  Professor  Jacob- 
son  suggested  that  this  latter  part  was  a  rudi- 
ment of  the  right  half  or  horn  of  the  uterus. 
It  may  perhaps,  however,  be  more  properly 
regarded  as  the  commencement  of  the  right 
Fallopian  tube,  and  in  this  case  it  would,  if 
continued  onwards,  have  been  joined  to  the 
neck  of  the  uterus, — an  arrangement  which 
would  be  quite  in  accordance  with  the  usual 
deep  and  displaced  origin  of  one  of  the  tubes 
in  instances  of  congenital  obliquity  of  the 
uterus. 

The  child  was  malformed  in  other  respects 
also.  The  anus  was  imperforate,  and  the 
rectum  (n)  opened  into  the  urinary  bladder, 
which  was  very  contracted.  The  kidneys  (m) 
were  irregularly  formed,  and  lay  near  the  pro- 
montory of  the  sacrum.  There  was  an  acces- 
sory spleen,  and  the  formation  of  the  heart  and 

VOL.  II. 


large  vessels  was  abnormal.  The  other  twin 
child  was  well  formed  and  lived. 

b.  The  case  of  transverse  hermaphroditism 
observed  by  Bouillaud*  was  even  still  better 
marked  than  that  of  Eschricht.  Valmont,  the 
individual  who  was  the  subject  of  it,  died  in 
one  of  the  hospitals  of  Paris  of  the  epidemic 
cholera.  He  was  a  hatter  by  trade,  and  had 
been  married  as  a  male.  No  further  particulars 
of  his  history  or  habits  could  be  obtained. 
The  following  was  found  by  MM.  Manec 
and  Bouillaud  to  be  the  state  of  the  external 
and  internal  sexual  organs. 

Externally  there  was  a  penis  (fig.  298)  of  a 


Fig.  298. 


medium  size,  terminating  in  a  regularly  formed 
glans  (a),  and  furnished  with  a  prepuce  (b). 

The  urethra  (fig.  299,  b  b)  opened  on  the 
inferior  side  of  the  glans  (fig.  298  &  299,  a ). 
In  its  course  from  this  point  backwards  to  tlie 
bladder,  it  perfectly  resembled  the  urethra  of  the 
male,  and  was  surrounded  at  its  origin  by  a  well- 
formed  prostate  gland  (fig.  299,  k  k).  Cowper's 
glands  were  also  present  (fig.  298,  d ).  The 
verumontanum  or  caput  gallinaginis  was  dis- 
tinct, as  well  as  the  orifices  of  the  prostatic 
follicles ;  but  the  usual  openings  of  the  seminal 
canals  could  not  be  found.  The  corpus  spon- 
giosum urethra  (fig.  298,  g)  and  the  corpora 
cavernosa  (fig.  299,  m  m)  were  as  well  deve- 
loped as  in  the  perfect  male  subject.  The 
scrotum  was  small,  and  did  not  contain  any 
testicles;  it  presented  on  its  middle  a  line  or 
raphe  extending  from  the  prepuce  to  the  anus, 
and  which  was  harder  and  better  marked  than 
it  usually  is  upon  male  subjects.  The  various 
muscles  of  the  male  perinreum  (fig.  298,  c  c) 
were  present,  and  very  perfectly  formed.  The 
constrictoresurinos  muscles  (e )  were  particularly 
long  and  thick. 

In  the  cavity  of  the  pelvis  two  ovaries  (fig. 
399,  d  d),  similar  in  form  and  structure, 
according  to  M.  Manec,  to  those  of  a  girl  of 
fifteen  or  sixteen  years  of  age,  or  (to  adopt 

*  Journ.  Hebdom.  de  Med.,  torn.  x.  p.  466. 
"  Exposition  Raisonnee  d'un  cas  de  nouvelle  ct 
singuliere  variete  d'hermapluodisme  observce  chez 
riioinme." 

3  A 


706 


HERMAPHRODITISM. 


-Fig.  299. 


M.  Bouillaud's  statement)  two  bodies  in  some 
sort  fibrous,  and  perhaps  intermediate  in 
their  structure  between  ovaries  and  testicles, 
were  found  along  with  two  Fallopian  tubes 
(Jig.  299,  g  g),  having  each  a  fimbriated  ex- 
tremity at  one  end,  and  opening  by  the  other 
into  the  cavity  of  an  uterus  (Jt)  which  occupied 
the  usual  situation  of  that  organ  in  the  female, 
and  opened  inferiorly  into  a  kind  of  vagina  (e). 
The  internal  surface  of  the  uterus  showed  the 
usual  arborescent  wrinkles  of  this  organ  in  the 
unimpregnated  state  ;  the  os  tinea;  was  regularly 
formed  ;  the  vagina  was  about  two  inches  long, 
and  of  a  middle  size,  and  presented  internally 
numerous  ridges,  such  as  are  met  with  in 
virgins.  This  canal,  when  opposite  the  neck 
of  the  bladder  at  /',  became  much  contracted, 
and  was  continued  downwards  in  the  form  of 
a  small  tube  to  the  membraneous  portion  of 
the  urethra,  into  which  it  entered  by  a  narrow 
orifice.  The  broad  ligaments  of  the  uterus  were 
normally  formed  ;  the  round  ligaments  passed 
through  the  inguinal  canal  accompanied  each 
by  an  artery  larger  than  that  of  the  correspond- 
ing one  in  the  female  sex. 

The  external  appearance  and  form  of  Valmont 
are  described  by  M.  Bouillaud  as  having  been 
intermediate  between  those  of  the  male  and 
female  sex.  The  stature  was  short ;  the  mam- 
mary glands  and  nipples  were  well  developed ; 
the  face  was  bearded ;  but  the  general  phy- 
siognomy was  still  delicate.  The  body  was  fat; 
the  hands  and  feet  were  small ;  the  pelvis  was 
shallow ;  and  the  haunches  were  wider  than  in 
a  well-formed  man. 


C.  Double  or  vertical  hermaphroditism. — 
In  the  two  divisions  or  orders  of  true  herma- 
phroditism which  have  been  already  considered, 
we  have  seen  re-united  upon  the  body  of  the 
same  individual  more  or  fewer  of  the  organs 
of  the  two  sexes,  but  so  arranged  as  not  neces- 
sarily at  least  to  present  the  occurrence  of  actual 
duplicity  in  any  of  the  corresponding  male 
and  female  parts.  In  both  lateral  and  trans- 
verse hermaphroditism  the  type  of  the  sexual 
apparatus  is  in  fact  single  in  so  far  that  it  con- 
sists, in  almost  all  cases,  in  the  presence  at 
one  part  of  an  organ  or  organs  differing  in 
sexual  type  from  those  that  are  present  at  other 
parts,  without  there  necessarily  co-existing  at 
any  one  point  the  two  corresponding  male 
and  female  organs.  In  the  present  or  third 
variety,  however,  of  true  hermaphroditism,  we 
come  to  a  tendency  to  actual  sexual  duplicity, 
in  the  co-existence  of  two  or  more  of  the  ana- 
logous organs  of  the  two  sexes  upon  the  same 
side,  or  in  the  same  vertical  line  of  the  body. 
For,  supposing  we  viewed,  either  from  before 
or  behind,  the  reproductive  organs  belonging 
to  the  two  sexes  all  stretched  out  upon  the 
same  erect  plane,  so  that  their  corresponding 
organs  should  be  exactly  superimposed  upon 
one  another, — as  the  two  female  ovaries  upon 
the  two  male  testicles,  the  Fallopian  tubes  upon 
the  vasa  deferentia,  the  uterus  upon  the  vesi- 
cular seminales  and  prostate  gland,  &c, — we 
should  find  in  vertical  or  double  hermaphro- 
ditism more  or  fewer  of  those  analogous  organs 
of  the  two  sexes  that  were  thus  placed  upon 
one  another,  and  that  consequently  lay  in  the 
same  vertical  line,  or  upon  the  same  side  of  the 
body,  co-existing  together  at  the  same  time 
upon  the  same  individual. 

Double,  vertical,  or  complex  hermaphro- 
ditism differs  much  in  variety  and  degree  in 
different  cases,  from  the  imperfect  repetition  of 
two  only  of  the  corresponding  organs  of  the 
male  and  female  upon  the  same  body,  to  the 
reunion  or  co-existence  of  almost  all  the  genital 
organs  of  both  sexes  upon  one  individual. 

For  the  purpose  of  contrasting  and  collect- 
ing together  as  much  as  possible  the  more  ana- 
logous cases,  we  shall  arrange  the  instances  of 
double  hermaphroditism  under  three  genera 
or  divisions;  the  first  including  cases  in  which 
there  co-existed  a  female  uterus  and  male  vesi- 
cular seminales,  with  a  general  female  type; 
the  second,  those  in  which  a  female  uterus, 
occasionally  provided  with  Fallopian  tubes, 
was  added  to  an  organization  that  was  in  other 
respects  essentially  male ;  and  the  third  com- 
prehending all  examples  in  which  ovaries  and 
testicles  are  alleged  to  have  been  repeated  toge- 
ther upon  one  or  both  sides  of  the  body.  Other 
divisions  of  double  hermaphroditism  may  be- 
come necessary  under  the  accumulation  of  new 
varieties  of  cases,  but  we  believe  it  will  be 
possible  to  arrange  all  the  instances  hitherto 
recorded  under  one  or  other  of  the  above  di- 
visions. In  classifying  and  describing  these 
instances  we  shall  in  the  meanwhile  offer  no 
observations  on  the  probable  anatomical  mis- 
takes that  have  been  committed  in  the  exami- 


HERMAPHRODITISM. 


707 


nation  of  individual  cases.  We  reserve  this 
important  subject  for  special  consideration 
under  a  separate  head,  where  we  shall  endea- 
vour to  shew  the  numerous  sources  of  error 
with  which  the  observation  of  individual  ex- 
amples and  varieties  of  complex  hermaphro- 
ditism is  beset. 

1.  Male  vesicular  seminales,  4'C-  superadded 
to  organs  of  a  female  sexuul  type. — In  this  first 
genus  of  double  hermaphroditism  we  find  two 
female  ovaries,  or  bodies  resembling  ovaries, 
and  an  imperfect  uterus  co-existing  with  two 
male  vesiculae  seminales,  which  are  occasion- 
ally accompanied  also  with  rudiments  of  the 
vasa  deferentia.  One  of  the  free-martins  de- 
scribed by  Mr.  Hunter  *  is  referable  to  this 
variety  of  double  hermaphroditism.  The  ex- 
ternal genital  organs  and  mammae  resembled 
those  of  the  cow,  but  were  smaller  in  size. 
The  vagina,  beyond  the  opening  of  the  urethra 
into  it,  was,  with  the  uterus  itself,  impervious. 
The  imperfect  uterus  divided  into  two  horns, 
at  the  end  of  which  were  the  ovaria.  On  each 
side  of  the  uterus  there  was  an  interrupted  vas 
deferens  broken  off  in  several  places  ;  and  be- 
tween the  bladder  and  vagina  these  vasa  de- 
ferentia terminated  in  two  vesiculae  seminales. 
The  ducts  from  the  vesiculae  and  the  vasa  de- 
ferentia opened  into  the  vagina.  In  this  in- 
stance we  have  all  the  female  organs  present, 
but  imperfect  in  their  development ;  and  at  the 
same  time  there  is  superadded  to  them  a  tubu- 
lar structure,  formed,  according  to  Mr.  Hun- 
ter's opinion,  of  the  male  vesiculae  seminales 
and  vasa  deferentia. 

We  have  met  with  a  free-martin  cow,  in 
which  upon  dissection  we  found  an  arrange- 
ment of  sexual  parts  very  similar  to  that 
described  in  the  preceding  case.  The  uterus, 
however,  though  small,  was  pervious  for  a 
distance  of  some  inches  above  the  vagina ; 
and  at  the  abdominal  end  of  each  blind  Fal- 
lopian tube  there  was  a  dilated  sac  of  con- 
siderable size  lined  by  peritonaeum,  and  open- 
ing into  the  abdominal  cavity  by  a  small  orifice. 
These  sacs  we  considered  as  abortive  attempts 
at  the  formation  of  the  fimbriated  extremities. 
The  imperfect  bodies  which  we  considered  as 
testicles  were  placed  near  the  cavities  which 
we  mention,  in  the  situation  of  the  ovaries. 
They  were  small  in  size,  and  of  an  oblong 
shape.  On  a  section  being  made  of  them, 
they  shewed  internally  a  kind  of  dense  ho- 
mogeneous yellow  tissue,  dotted  or  crossed 
with  strongly  marked  white  lines.  The  vasa 
deferentia  could  be  traced  along  each  side  of 
the  uterus  in  the  form  of  broken  dense  cords. 
The  vesiculae  seminales  were  large  and  partially 
hollow,  and  near  them  on  each  side  there  was 
an  oblong  body  of  considerable  size,  having 
the  appearance  of  Cowper's  glands.  The  tubes 
from  them,  and  from  the  vesiculae  seminales, 
opened  near  the  os  tincae  into  a  vagina  of  nearly 
the  usual  size. 

2.  An  imperfect  female  uterus,  &;c.  super- 
added to  a  sexuul  organization  essentially  male. 

*  See  An.  Kcon.  p.  64.    Mr. Well's  free-martin. 


— In  the  cases  included  under  this  second 
division  of  double  hermaphroditism  there  exist 
a  male  testicle,  or  testicles,  vasa  deferentia, 
and  vesiculae  seminales,  along  with  a  female 
uterus.  The  uterus  occupies  its  normal  situ- 
ation between  the  bladder  and  rectum.  It  is 
sometimes  defectively  developed,  and  of  a 
membranous  structure ;  and  occasionally  it  is 
not  provided  with  Fallopian  tubes,  or,  in  the 
quadruped,  with  comua.  The  cavity  of  the 
uterus  communicates  with  a  vagina  that  either 
opens  in  its  usual  situation  externally,  or,  as 
happens  more  frequently,  joins  the  male  ure- 
thra. In  some  cases  the  vagina  is  wanting, 
and  the  uterus  opens  directly  into  the  canal  of 
the  urethra. 

Several  cases  of  sexual  malformation  in  the 
ram,  goat,  and  dog  referable  to  this  variety  of 
double  hermaphroditism  have  been  described 
by  different  authors;  and  various  analogous 
instances  have  now  also  been  observed  in  the 
human  subject. 

In  a  lamb  described  and  delineated  by  Mr. 
Thomas,*  all  the  external  parts  were  male,  but 
the  scrotum  was  divided  or  hypospadic.  In- 
ternally there  were  two  perfect  male  testicles 
in  the  situation  of  the  ovaries,  with  their  epidi- 
dymes,  vasa  deferentia,  and  vesiculae  seminales; 
and  a  well-formed  two-horned  uterus  furnished 
with  its  usual  ligaments,  and  with  Fallopian 
tubes  that  ran  up  and  terminated  in  a  tortuous 
convoluted  manner  upon  the  testicles.  The 
body  of  the  uterus  possessed  the  common  rugose 
structure,  but  the  horns  were  lined  by  a  smooth 
membrane  without  their  usual  glandular  bodies 
internally.  At  the  anterior  extremity  of  the 
fundus  uteri,  a  thick  semilunar  valve,  which 
seemed  to  correspond  to  the  os  tincae,  passed 
across  and  hardly  allowed  a  fine  probe  to  be 
entered  over  its  upper  edge.  The  vagina 
scarcely  existed,  and  formed  only  a  short 
smooth  pouch  terminating  below  in  a  cul-de- 
sac.  The  male  vesiculae  seminales  and  vasa 
deferentia  entered  the  male  urethra  in  their 
normal  situation  at  the  caput  gallinaginis. 

Gurltf  has  described  and  delineated  the 
sexual  parts  of  a  goat  in  which  all  the  inter- 
nal male  genital  organs,  with  the  exception 
of  Cowper's  glands,  were  found  (jig.  300). 
There  was  also  present  an  uterus  (c)  provided 
with  long  but  narrow  and  curved  cornua  (ff), 
that  accompanied  the  vasa  deferentia  and  tes- 
ticles through  the  abdominal  rings,  and  ended 
blind  at  the  epididymes.  The  testicles  lay 
externally  upon  the  udder,  which  was  of  con- 
siderable size.  The  scrotum  was  absent;  the 
penis  (g)  was  short,  tortuous,  and  imperforate  ; 
and  there  was  a  fissure  in  the  perinaeum  into 
which  the  urethra  (/<)  opened. 

StellatiJ  has  recorded  an  analogous  case  in 
the  same  animal.     The  male  sexual  organs 

*  London  Med.  and  Phys.  Journ.  vol.  ii.  (1799), 
p.  1,  with  a  good  drawing  of  the  malformed  organs 
of  generation. 

t  Lehibuch  der  Pathol.  Anat.  Bd.  ii.  s.  195. 
pi.  ix.  fig.  1  &  "2,  and  pi.  xxii.  fig.  3  &  4. 

t  Atti  del  Real  Instit.  d'incoragg.  alle  Sc.  Nat. 
Naples,  torn.  iii.  p.  380. 

3  A  2 


703 


HERMAPHRODITISM. 


Fig.  300. 


a  a,  the  testicles  ;  b  b,  epididymes  -}  c  c,  vasa  defe- 
rentia ;  dd,  vesicular  seminales. 

were  not  entirely  complete,  and  there  were 
superadded  to  them  a  female  vagina  and  an 
imperfectly  developed  uterus,  the  Fallopian 
tubes  of  which  ran  towards  the  inguinal  rings, 
and  terminated  with  them  upon  the  epididymes 
of  the  testicles. 

Another  instance  of  hermaphroditic  malfor- 
mation in  the  goat,  detailed  at  great  length  by 
Meckel,*  seems  also  in  its  principal  points 
justly  referable  to  the  present  division  of  cases, 
although  there  was  at  the  same  time  a  tendency, 
in  the  unequal  size  of  the  two  cornua  uteri, 
&c,  to  a  degree  of  lateral  hermaphroditism. 

Professor  Mayer,  of  Bonn,f  has  detailed  at 
length  the  dissection  of  three  hermaphroditic 

*  Roil's  Archiv  fuer  die  Physiologie,  Bd.  xi. 
s.  334-8. 

Wo",?68  Select-  Pr«parat.  Mus.  Anat.  Bonn, 
p.  17-20.  tab.  iv.  fig.  5,  and  tab.  v.  figs.  1,2,  &  3. 


goats,  in  all  of  which  the  conformation  of  the 
sexual  parts  resembled  in  its  more  essential 
parts  the  preceding  cases  of  Thomas  and  Gurlt. 
In  all  the  three  instances  there  were  found  two 
male  testicles  with  their  epididymes,  vasa  de- 
ferentia,  and  vesicular  seminales ;  and  at  the 
same  time  there  was  present  a  well-marked 
female  two-homed  uterus,  with  a  vagina  open- 
ing into  the  urethra.  In  the  first  case  the  large 
hollow  comua  uteri  terminated  in  blind  ex- 
tremities, and  there  were  only  very  short  im- 
pervious rudiments  of  the  Fallopian  tubes. 
In  the  second  case,  at  the  extremity  of  the 
right  horn  of  the  uterus,  a  blind  appendicula 
was  situated,  formed  by  a  vestige  (according 
to  Mayer)  of  the  Fallopian  tube ;  and  from 
this  a  ligament  was  sent  off  to  the  correspond- 
ing testicle ;  a  similar  ligament,  but  no  appen- 
dicula, existed  on  the  left  side.  In  the  third 
case  both  Fallopian  tubes  were  present,  and 
each  ended  in  a  bursa  formed  by  the  lamina  of 
the  peritonaeum,  and  partly  surrounding  the 
testicle  and  epididymes.  In  two  of  the  in- 
stances the  ejaculatory  ducts  seem  to  have 
opened  into  the  urethra  near  the  point  at  which 
the  vagina  terminated  in  it ;  and  in  one  of  the 
cases  they  opened  into  the  canal  of  the  vagina 
itself  before  it  joined  that  of  the  urethra.  All 
the  external  organs  were  male,  but  malformed 
in  so  far  that  the  penis  was  short,  and  in  two 
of  the  cases  somewhat  twisted;  and  the  scrotum 
was  either  small  or  wanting. 

The  same  author*  has  described  the  dis- 
section of  a  dog,  the  sexual  organs  of  which 
exhibited  a  similar  variety  of  hermaphroditic 
malformation.  The  Fallopian  tubes  were  per- 
vious throughout  in  this  instance,  and  at  their 
further  extremities  opened  upon  the  neigh- 
bouring cellular  tissue.  The  body  of  the  two- 
horned  uterus  was  very  small.  On  compres- 
sing the  epididymes  and  vasa  deferentia,  a  fluid 
resembling  semen  issued  from  the  openings  of 
the  latter  into  the  urethra.  The  external  sexual 
parts  were  those  of  a  hypospadic  male. 

Several  cases  of  hermaphroditic  malforma- 
tion in  the  human  subject,  similar  in  their 
anatomical  characters  to  the  preceding,  have 
been  described  by  Columbus,  Harvey,  Petit, 
Ackermann,  and  Mayer. 

a.  In  a  person  with  external  hypospadic 
male  organs,  Columbus-f  found  two  bodies  like 
testicles  in  the  situation  of  the  ovaries,  and 
larger  in  size  than  the  latter  female  organs  na- 
turally are.  From  each  of  these  testiform 
bodies  two  sets  of  tubes  arose,  one  of  which, 
like  the  male  vasa  deferentia,  passed  on  to  the 
root  of  the  penis  and  opened  into  the  urethra ; 
while  the  other,  like  the  female  Fallopian  tubes, 
were  inserted  into  an  uterus.  The  prostate 
gland  was  absent. 

b.  Harvey  \  has  mentioned  a  very  small  her- 
maphroditic embryo,  on  which  he  found  a 
two-horned  uterus  with  two  testicles  of  a  very 

*  lb.  p.  16.  tab.  iv.  fig.  3,  external  parts  of 
generation  ;  fig.  4,  internal, 
t  De  Re  Anat.  lib.  xv. 
}  De  Gen.  Anim.  Exerc.  Ixix.  p.  304. 


HERMAPHRODITISM. 


709 


small  size,  and,  near  the  diminutive  penis,  some 
traces  of  a  prostate  gland. 

c.  The  observation  of  M.  Petit,*  of  Namur, 
is  still  more  complete.  On  the  body  of  a  sol- 
dier, aged  twenty-two,  who  died  of  his  wounds, 
and  whose  external  organs  appear  to  have 
presented  no  deviation  from  the  male  type 
except  in  the  absence  of  the  testicles  from  the 
scrotum,  these  bodies,  with  male  vasa  defe- 
rentia,  vesiculae  seminales,  and  a  prostate,  were 
found  to  co-exist  with  female  Fallopian  tubes, 
and  an  uterus  that  was  attached  to  the  neck 
of  the  urinary  bladder,  and  opened  into  the 
urethra  between  this  neck  and  the  prostate. 
The  form  of  this  imperfect  uterus,  M.  Petit 
remarks,  merited  for  it  rather  the  name  of  a 
vagina  than  of  an  uterus,  and  it  resembled 
more  this  organ  in  the  female  quadruped  than 
in  women.  From  the  body  of  the  uterus,  at 
three  inches  from  its  entrance  into  the  urethra, 
two  Fallopian  tubes  arose.  These  tubes  were 
perforated,  and  were  three  inches  and  a  half 
long;  their  abdominal  extremities  were  not 
loose  and  provided  with  fimbriae,  but  were  at- 
tached to  a  small  soft  body  on  each  side, 
occupying  nearly  the  natural  situation  of  the 
ovaries,  but  having  the  substance  or  structure 
of  the  testicles,  and  provided  with  an  epidi- 
dymis and  vas  deferens.  The  vasa  deferentia 
were  each  seven  inches  and  a  half  long,  and 
were  attached  to  two  long  and  rather  slender 
vesiculoe  seminales  placed  alongside  of  the 
uterus.  The  vesiculae  opened  into  the  urethra 
by  two  ducts. 

In  a  note  appended  to  this  case,  M.  Petit 
states  that  he  had  been  consulted  by  a  man 
who  rendered  blood  by  the  penis  regularly 
every  month,  without  pain  or  any  troublesome 
symptom.  Perhaps,  adds  M.  Petit,  this  man 
had  also  a  concealed  uterus.  We  have  been 
informed,  on  credible  authority,  of  two  similar 
cases,  the  one  in  a  young  unmarried  man  of 
seventeen  years  of  age,  and  the  other  in  a  per- 
son who  had  been  married  for  several  years 
without  his  wife  having  had  any  children.  In 
both  of  these  cases  the  discharge  was  in  very 
considerable  quantity,  and  perfectly  regular  in 
its  monthly  occurrence.  Did  it  consist  in  a 
periodical  haemorrhage  from  the  urinary  blad- 
der or  passages  only  ?  or  was  it,  as  M.  Petit 
seems  to  suppose  in  his  instance,  of  a  true 
menstrual  character,  and  produced  by  the  re- 
productive organs  of  the  female  existing  inter- 
nally, and  communicating  with  the  bladder  or 
urethra  ? 

d.  Professor  Ackermann,f  of  Jena,  pub- 
lished in  1805  the  following  interesting  case  of 
the  present  variety  of  hermaphroditic  malfor- 
mation. It  occurred  in  an  infant  that  lived 
about  six  weeks  after  birth.  On  dissection, 
two  testicles  were  found;  one  of  them  had 
descended  into  the  scrotum  or  labium;  the 
other  had  advanced  no  further  than  the  groin. 
Both  were  perfectly  formed,  and  had  their  usual 
appendages  complete.    In  the  natural  situa- 

*  Hist,  de  1'Acad.  Roy.  des  Sc.  for  1720,  p.  38. 
t  Infantis  androgyni  historia  et  iconographia, 
Edinb.  Med.  and  Surg,  .lonrn.  vol.  iii.  p.  202. 


tion  of  the  female  uterus,  there  was  found  a 
hollow  pyriform  organ,  which,  from  its  locality 
and  connections,  was  supposed  to  be  an  ute- 
rus, though  its  coats  were  finer  and  thinner, 
and  its  cavity  greater  than  naturally  belongs  to 
that  viscus.  Duplicatures  of  peritonaeum,  re- 
sembling the  ligamenta  lata,  connected  this  im- 
perfect uterus  with  the  sides  of  the  pelvis,  and 
its  cavity  opened  into  a  kind  of  short  vagina, 
which  soon  united  with  the  urethra,  and  formed 
one  common  canal  with  it  (vagina  urethralis). 
The  vasa  deferentia  ran  from  the  testicles 
towards  the  superior  angles  of  the  uterus,  and 
penetrated  into  its  substance  at  the  points 
where  the  Fallopian  tubes  are  usually  placed. 
Without  opening  here,  however,  they  passed 
onwards  under  the  internal  mucous-like  mem- 
brane of  the  uterus  and  vagina,  and  at  length 
terminated,  by  very  small  orifices,  in  the  va- 
gina urethralis.  Immediately  previous  to  en- 
tering the  ligamenta  lata,  each  vas  deferens 
formed  a  number  of  convolutions,  conglome- 
rated into  a  mass  resembling  a  vesicula  semi- 
nalis. 

e.  Steghlener*  has  described  at  great  length 
the  case  of  an  infant  that  survived  only  for 
half  an  hour  after  birth,  and  upon  whose  body 
he  found  perfect  external  male  organs  (Jig. 
301,  a  b),  and  internally  two  small  elon- 
gated testicles  (c  c),  with  their  epididymes  (g  g), 
the  convolutions  of  their  vasa  deferentia  (6  b) 


Fig.  301. 


*  De  Htrmaphr.  Nat.  p.  104. 


710 


HERMAPHRODITISM. 


distinctly  marked.  Between  the  rectum  and 
bladder  there  was  placed  a  very  large  pear- 
shaped  bag  or  pouch  (./"),  with  firm,  coria- 
ceous, but  not  thick  walls,  and  distended  with 
fluid.  This  bag  or  imperfect  cystoid  uterus 
terminated  inferiorly  by  a  narrow  neck,  in  a 
vagina  that  opened  into  the  urethra,  in  the  situ- 
ation of  the  verumontanum,  and  was  there 
dilated  into  a  large  bag  or  ampulla,  occupying 
exactly  the  site  of  the  prostate  gland,  and  re- 
sembling this  organ  also  in  its  form  and  posi- 
tion. The  internal  membrane  of  the  uterus 
was  collected  at  its  neck  into  numerous  val- 
vular-like folds,  and  that  of  the  vagina  had 
also  a  rugous  or  plicated  arrangement.  From 
the  fundus  of  the  large  sac  of  the  uterus,  and 
not  from  its  angles,  but  from  near  its  middle, 
two  impervious  solid  ducts  (Fallopian  tubes, 
or  rather  vasa  deferentia,)  arose,  and  after  a 
somewhat  flexuous  course  reached  the  testicle 
(c  f)  lying  in  the  superior  part  of  the  iliac 
fossce.  These  ducts  had  attached  to  them  at  one 
or  two  points  a  number  of  small  reddish  nodules 
(6  b),  consisting,  according  to  Steghlener,  of 
glandular  granules,  and  described  by  Acker- 
mann  in  his  case  as  vesicular  seminales.  The 
canal  of  the  urethra  was  obliterated  for  a  short 
distance  towards  the  fossa  navicularis,  and  the 
urinary  bladder  ( ;')  and  uterus  (i  i)  were  ex- 
tremely distended,  and  the  left  kidney  (>«)  was 
vesicular. 

Mayer,  in  the  work  already  referred  to,*  has 
described  and  delineated  the  following  five 
cases  of  the  present  species  of  hermaphroditic 
malformation  in  the  human  subject,  all  of 
which  he  had  himself  met  with  and  dissected. 

/".  In  a  fcetus  of  the  fourth  month,  and 
affected  withomphaloceleand  extroversion  of  the 
urinary  bladder, lie  found  male  testicles  (fig.  302, 

Fig.  302. 


a  a)  with  their  epididymes  (b  b),  and  a  two- 
horned  uterus  (c)  terminating  in  a  vagina  (tf), 
that  opened  into  the  posterior  part  of  the  uri- 
nary bladder  (e).  From  the  left  testicle  a  con- 
torted vas  deferens  (  /)  arose,and  ran  down  to  the 
vagina;  the  right  vas  deferens  (g)  was  shorter, 

*  Icones  Select.  &c.  p.  8-16.  See  also  Walther 
and  Giaefe's  Journal  der  Chirurgie  und  Augen- 
heilkunde,  Bd.  vii.  lift.  3,  and  I3d.  viii.  Hft.  2. 


and  became  thread-like,  and  disappeared  near 
the  corresponding  cornu  of  the  uterus.  A  ru- 
diment only  of  the  left  male  vesicula  seminalis 
was  observable.  The  external  organs  were 
male ;  the  glans  penis  (h)  was  imperforate. 

g.  In  another  fcetus  of  the  sixth  month,* 
there  existed  a  perfect  set  of  internal  and  exter- 
nal male  sexual  organs,  viz.,  testicles,  epididy- 
mes, vasa  deferentia,  and  vesicul*  seminales, 
with  a  prostate  gland  and  a  normally  formed 
penis  and  scrotum.  But  besides  these,  there 
was  also  present  an  imperfect  female  uterus, 
the  body  of  which  divided  into  two  cornua,  the 
right  longer  and  incurvated,  the  left  shorter  and 
sacciform.  The  neck  of  the  uterus  was  marked 
internally  by  its  usual  arborescent  appearance  ; 
and  it  opened  into  a  vagina  that  terminated  in 
the  urethra  near  the  exit  of  the  latter  from  the 
urinary  bladder. 

h.  In  a  third  casef  of  hermaphroditic  malfor- 
mation in  an  infant  who  diedof  convulsions  when 
six  months  old,  Mayer  found  the  following  blend- 
ing of  the  organs  of  the  two  sexes.  Of  the 
internal  male  genital  organs  there  were  present 
two  bodies  at  the  inguinal  rings  that  were  evi- 
dently testicles,  {fig.  303,  a,  a)  as  was  proved 


Fig.  303. 


not  only  by  their  position,  but  by  their  form, 
coverings,  connections,  and  internal  structure, 
("  theirsubstance,"  says  Mayer,  "  being  evident- 
ly composed  of  yellow  canals");  their  epidi- 
dymes (b  b)  were  also  distinctly  developed,  and 
each  of  them  sent  off  a  vas  deferens  (c  c),  which 

*  Icones,  p.  8.  tab.  ii.  fig.  5. 

t  Icones,  p.  9,  tab.  iii.  fig.  1  and  2.  *j 


HERMAPHRODITISM. 


711 


was  furnished  with  a  corresponding  multilocular 
vesicula  seminalis  (d  d).  Of  the  internal  fe- 
male sexual  organs  there  were  found  a  perfectly 
developed  uterus  (e  e),  with  its  broad  («  w) 
and  round  (u  o)  ligaments  naturally  formed 
and  placed,  and  provided  with  two  Fallopian 
tubes  (ff)  that  followed  the  course  of  the 
testicles  through  the  inguinal  canals,  and  a  va- 
gina (g)  which  opened  into  the  urethra  (//)  near 
its  external  orifice.  The  ejaculatory  ducts  of 
the  male  vesicula?  seminales  opened  into  this 
vagina  at  I  and  m.  The  internal  surface  of 
the  vagina  was  already  beginning  to  present 
the  appearance  of  its  usual  rugae.  The  cavity 
of  the  uterus  was  triangular,  and  exhibited  on 
the  internal  part  of  the  cervix  its  characteristic 
plicated  or  arborescent  structure.  The  Fallo- 
pian tubes  were,  at  their  uterine  orifices,  of  a 
large  caliber;  their  cavity  afterwards  became 
suddenly  contracted,  and  then  again  ddated, 
and  terminated  at  their  ulterior  extremities, 
where  they  lay  in  contact  with  the  testicles  at 
the  external  inguinal  rings,  in  blind  sacs  (i  i), 
without  any  very  distinct  appearance  of  fim- 
bria;. The  external  genital  parts  in  this  very 
interesting  case  were  of  a  doubtful  nature, 
being  referable  either  to  those  of  a  hypospadic 
male,  or  of  a  female  with  a  large  clitoris,  but 
without  nympha;,  the  meatus  urinarius  being  in 
its  normal  situation,  but  leading  behind  to  the 
cavities  of  both  the  urinary  bladder  and  uterus. 
The  circle  of  the  pelvic  bones  was  large. 

i.  The  two  other  instances  described  by 
Mayer  occurred  in  adult  subjects,  and  the  mal- 
formation in  both  of  them  differed  from  that 
found  in  the  cases  just  now  cited  in  this,  that 
there  was  only  one  testicle  present  along  with 
the  imperfect  uterus. 

The  subject  of  one  of  these  cases*  was  a 
person  who  died  at  the  age  of  eighteen,  and 
whose  external  sexual  organs  were  those  of  a 
hypospadic  male,  with  a  narrow  perinaeal  canal 
or  fissure.  On  dissection  this  perinaeal  canal 
was  found  to  communicate  anteriorly  with 
the  urethra,  and  posteriorly  with  a  vagina  of  two 
inches  and  nine  lines  in  length,  and  five  or  six 
lines  in  caliber.  The  anterior  and  posterior 
column  of  rugae  belonging  to  the  vagina  was 
only  slightly  marked.  Its  canal  led  to  a 
large  dilated  uterus,  the  superior  part  of  which 
was  unfortunately  cut  away  with  some  dis- 
eased viscera  before  the  genital  organs  were 
examined;  but,  from  the  portion  left,  this 
organ  seemed  to  resemble  the  uterus  of  quad- 
rupeds in  its  oblong  form,  and  in  the  thinness 
of  its  walls,  which  were  composed  of  a  caver- 
nous fibro-vascular  texture,  and  full  of  lacunas. 
The  usual  arborescent  appearance  of  the  inter- 
nal surface  of  the  os  uteri  was  very  perfectly 
marked.  Besides  these  female  organs,  there 
was  a  well-formed  male  prostate  gland  at  the 
neck  of  the  bladder ;  and  behind  the  abdomi- 
nal ring  of  the  right  side,  a  small  roundish 
body,  similar  in  form  and  texture  to  the  testi- 
cle, and  having  the  cremaster  muscle  adhering 
to  its  membranous  involucrum.  There  were 
no  traces  of  any  similar  organ  on  the  left  side. 

*  Iconcs,  p.  11.  tab,  iii.  fig.  3  and  4. 


On  both  sides  some  portions  of  a  crural  were 
seen,  but  whether  they  were  the  remains 
of  the  vasa  deferentia  or  Fallopian  tubes  was 
not  ascertained  on  account  of  the  previous 
mutilation  of  the  uterus.  On  each  side  of  the 
neck  of  the  uterus  there  was  placed  a  vesicula 
seminalis,  provided  with  an  ejaculatory  duct 
that  opened  into  the  orifice  of  the  vagina. 
The  dimensions  of  the  pelvis  approached  much 
nearer  to  those  of  the  female  than  those  of  the 
male.  In  the  secondary  sexual  characters  of 
the  individual,  the  female  type  was  further  re- 
cognised in  the  want  of  prominence  in  the 
larynx,  in  the  slender  form  of  the  neck,  and 
(according  to  Professor  Mayer)  in  the  rounded 
shape  also  of  the  heart,  the  smallness  of  the 
lungs,  the  oblong  shape  of  the  stomach,  the 
large  size  of  the  liver,  the  narrowness  of  the 
forehead,  and  the  conformation  of  the  brain  ; 
while  the  individual  approximated,  on  the 
other  hand,  to  the  male  in  the  length  and  posi- 
tion of  the  inferior  extremities,  in  the  breadth 
of  the  thorax,  the  undeveloped  state  of  the 
mammae  and  the  hairy  condition  of  their  pa- 
pillae, and  in  the  existence  of  a  slender  beard 
upon  the  chin  and  cheeks. 

j.  In  the  second  adult  subject  (a  person  of 
eighty  years  of  age)  Mayer*  found,  on  the  left 
side  of  the  cavity  of  the  abdomen,  and  near 
the  inguinal  ring,  a  small  oval  body  exhibiting 
imperfectly  in  its  internal  structure  the  tubular 
texture  of  the  male  testicle,  and  having  an 
appendix  resembling  the  epididymis  attached 
to  it.  From  this  testicle  arose  a  vas  deferens, 
which  was  joined  in  its  course  by  a  vesicula 
seminalis,  and  ended  in  an  ejaculatory  duct. 
On  the  opposite  or  right  side  a  vesicula  semina- 
lis, having  no  continuous  cavity,  was  present ; 
but  no  vestige  of  a  corresponding  testicle,  vas 
deferens,  or  ejaculatory  duct  could  be  disco- 
vered. The  prostate  gland  was  present,  and 
regularly  formed.  In  the  cavity  of  the  pelvis 
an  uterus  was  found  with  parietes  of  moderate 
thickness,  and  of  the  usual  cavernous  texture; 
its  cervix  was  marked  internally  with  the  appear- 
ance of  the  natural  arborescent  ruga?.  Inferiorly 
it  opened  into  a  narrow  membranous  vagina, 
that  received  the  right  ejaculatory  duct,  then 
passed  through  the  body  of  the  prostate,  and 
latterly  joined  the  canal  of  the  urethra.  The 
fundus  of  the  uterus  could  not  be  examined,  as 
it  had  been  removed  in  a  previous  stage  of  the 
dissection.  The  external  parts  were  male  and 
naturally  formed,  with  the  exception  of  the 
penis,  which  was  shorter  than  usual,  and  had 
the  canal  of  the  urethra  fissured  inferiorly,  and 
the  meatus  urinarius  situated  at  its  root.  The 
individual  was  during  life  regarded  as  a  male, 
but  had  all  along  remained  in  a  state  of  celi- 
bacy. The  general  appearance  of  the  face  and 
body  was  that  of  an  imperfectly  marked  male, 
but  the  pelvis  was  broad  like  that  of  a  female. 

3.  Co-existence  of  J  cm  ale  ovaries  and  male 
testicles. — This  third  division  of  complex  or 
double  hermaphroditism  includes  all  those  cases 
in  which  a  male  testicle  and  female  ovary  exist 
together  either  upon  one  side  only,  or  upon 

*  Iconcs,  p.  15,  tab.  iv.  fig.  1  and  2» 


712 


HERMAPHRODITISM. 


both  sides  of  the  body.  With  this  arrange- 
ment, other  malformations  by  duplicity  of  the 
sexual  organs  are  generally  combined ;  but 
these  are  so  various  in  their  character  as  not 
easily  to  admit  of  any  useful  generalization. 
In  considering  this  third  division  of  complex 
hermaphroditism,  we  shall  mention,  first,  the 
cases  in  which  two  testicles  and  one.  ovary  are 
stated  to  have  co-existed ;  and  secondly,  those 
in  which  there  have  been  supposed  to  be  pre- 
sent two  testicles  and  two  ovaries. 

Two  testicles  and  one  ovary.- — The  two  dis- 
sections that  we  have  previously  detailed  of 
lateral  hermaphroditic  insects,  ( see  Lateral 
Hermaphroditism,  p.  696,)  shew  that  in  these 
two  cases  this  variety  of  sexual  duplicity  existed. 
It  appears  to  have  been  observed  also  in  two 
instances  of  hermaphroditic  malformation  in 
the  quadruped,  the  histories  of  which  have 
been  described  by  Mascagni  and  Mayer. 

In  a  bull,  nine  years  of  age,  and  which 
was  provided  with  the  usual  external  organs  of 
the  male,  Mascagni  found  internally,  on  dis- 
section, a  prostrate  gland  and  two  perfect 
vesicular  seminales,  vasa  deferentia,  epidi- 
dymes,  and  testicles.  The  testicles  and  epi- 
didymes  were  injected  with  mercury  through 
the  vasa  deferentia.  In  addition  there  was  dis- 
covered near  the  left  testicle,  and  connected  to 
it  by  peritonaeum  and  bloodvessels,  a  body 
having  the  structure  of  the  female  ovary  ;  and, 
in  its  normal  situation,  there  existed  a  distended 
double  uterus,  containing  from  fifteen  to  sixteen 
pounds  of  a  clear  fluid.  This  uterus  was 
furnished  with  two  Fallopian  tubes  at  its  upper 
part,  and  terminated  inferiorly  in  a  vagina, 
which  opened  by  a  small  orifice  into  the  male 
urethra.* 

In  a  goat  dissected  by  Mayer,  f  he  found 
two  testes  with  their  epididy  mes  fully  developed, 
and  vasa  deferentia  and  vesiculae  seminales. 
One  of  the  testes  was  placed  without  and  the 
other  still  remained  within  the  abdominal  cavity. 
At  the  same  time  there  were  present  a  large  fe- 
male vagina  communicating  with  the  urethra, 
and  a  double- horned  uterus  provided  with  two 
Fallopian  tubes.  One  of  these  tubes  terminated 
in  a  blind  canal,  but  the  other  had  placed  at 
its  abdominal  extremity  several  vesicles,  resem- 
bling, according  to  Mayer,  Graafian  vesicles, 
or  an  imperfect  ovary.  The  vesicute  seminales 
and  (through  regurgitation  by  the  urethra  and 
ejaculatory  ducts)  the  cavities  of  the  vagina 
and  uterus,  were  filled  with  about  four  ounces 
of  a  whitish  fluid,  having  the  colour  and  odour 
of  male  semen.  This  fluid  could  not  be  found 
by  the  microscope  to  contain  any  seminal  ani- 
malcules, but  only  simple  and  double  Monades 
( Monades  termones  et  guttulas ).  Bergmann, 
however,  is  alleged  to  have  found  it,  on 
analysis,  to  contain  the  same  chemical  principle 
that  characterizes  human  male  semen. 

Two  testicles  and  two  ovaries. — Various  in- 
stances have  now  been  published  in  which  this 
sexual  duplicity  has  been  supposed  to  exist 

*  Atti  dell'  Acad,  delle  Scienze  di  Siena,  t.  viii. 
p.  201. 

t  Icones,  p.  20. 


among  cattle  and  other  domestic  quadrupeds, 
as  well  as  in  the  human  subject. 

One  of  the  free-martins*  described  by 
Mr.  Hunter  comes  under  this  variety.  In  the 
case  referred  to,  in  the  situation  of  the  ovaries 
"  were  placed,"  to  use  Mr.  Hunter's  words, 
"  both  the  ovaria  and  testicles," — or,  as  Sir 
Everard  Home,  in  alluding  to  this  case,  more 
justly  expresses  it,  "  an  appearance  like  both 
testicles  and  ovaria  was  met  with  close  toge- 
ther."! The  two  contiguous  bodies  were  nearly 
of  the  same  size,  being  each  about  as  large  as 
a  small  nutmeg.  There  were  no  Fallopian 
tubes  running  to  the  ovaries,  but  a  horn  of 
an  imperfect  uterus  passed  on  to  them  on  each 
side  along  the  broad  ligament.  Pervious  vasa 
deferentia  were  found  ;  they  did  not,  however, 
reach  up  completely  to  the  testicle  on  either 
side,  or  form  epididymes.  The  vesicula;  semi- 
nales were  present,  and  much  smaller  than  in 
the  perfect  bull.  The  external  parts  appear  to 
have  been  those  of  the  cow,  but  smaller  than 
natural.  The  vagina  passed  on,  as  in  the  cow, 
to  the  opening  of  the  urethra,  and,  after  having 
received  it  and  the  orifices  of  the  seminal  ducts, 
it  began  to  contract  into  a  small  canal,  which 
ran  upwards  through  the  uterus  to  the  place  of 
division  of  that  organ  into  its  two  horns. 

Velpeau,t  in  his  work  on  Midwifery,  men- 
tions that  in  an  embryo  calf,  he  had  "  found 
reunited  the  testicles  and  ovaries,  the  vasa 
deferentia,  and  uterus." 

In  an  hermaphroditic  foal-ass,  Mr.  Hunter§ 
found  both  what  he  considered  to  be  two  ovaries 
placed  in  the  natural  situation  of  these  bodies, 
and  two  testicles  lying  in  the  inguinal  rings  in 
a  process  or  theca  of  peritonaeum  similar  to 
the  tunica  vaginalis  communis  in  the  male  ass. 
No  vasa  deferentia  or  Fallopian  tubes  could  be 
detected ;  but  there  was  a  double-horned 
uterus  present,  and  from  its  broad  ligaments, 
(to  the  edges  of  which  the  comua  uteri  and 
ovaries  were  attached,)  there  passed  down  on 
either  side  into  the  inguinal  rings  a  part  similar 
to  the  round  ligament  in  the  female.  The 
horns  and  fundus  of  the  uterus  were  pervious  ; 
but  its  body  and  cervix,  and  the  canal  of  the 
vagina  from  above  the  opening  of  the  urethra 
into  it,  were  imperforate.  The  external  parts 
were  similar  to  those  of  the  female  ass ;  but 
the  clitoris,  which  was  placed  within  the 
entrance  of  the  vagina,  was  much  larger  than 
that  of  a  perfectly  formed  female ;  it  measured 
about  five  inches.  The  animal  had  two 
nipples. 

Scnba  has  given  an  account||  of  an  herma- 
phroditic sheep,  in  which  two  large  testicles 
are  stated  to  have  been  found  in  the  scrotum, 
at  the  same  time  that  there  existed,  in  their  nor- 
mal situation,  two  moderately  sized  ovaries, 
and  a  small  uterus  furnished  with  two  appa- 
rently closed  Fallopian  tubes.  The  external 
sexual  parts  appear  to  have  been  those  of  a 

*  An.  Econ.  p.  63-64,  pi.  ix. 

t  Comp.  Anat.  vol.  iii.  p.  322- 

|  Traite  de  l'Art  des  Accouchemens,  t.  i.  p.  114. 

&  An.  Econ.  p.  58. 

\\  Schrifteu  dtr  Gesellschaft  Naturforschendcr 
Fieude  zu  Berlin,  Bd.  x.  s.  367. 


HERMAPHRODITISM. 


713 


malformed  male,  the  penis  being  short  and  im- 
pervious, the  scrotum  divided,  and  the  urethra 
opening  into  a  contracted  perineal  fissure  re- 
sembling the  female  vulva.  This  animal  had 
often  attempted  connection  with  the  female 
sheep. 

Borkhausen*  has  described  a  very  similar 
case  in  the  same  species  of  animal.  Each  half 
of  the  divided  scrotum  contained  a  testicle 
which  was  regularly  formed,  but  greater  in  size 
than  usual,  and  furnished  with  a  large  sperma- 
tic artery.  The  pelvis  contained  a  normal 
uterus,  which  was  smaller,  however,  than  na- 
tural ;  it  was  provided  with  its  usual  ligaments. 
The  Fallopian  tubes  were  present  but  imper- 
forate, and  the  two  ovaries  were  full  of  vesicles 
and  inclosed  in  a  strong  membrane.  The 
vagina  was  natural  and  opened  as  in  the  female. 
Behind  the  divided  scrotum  the  rudiment  of 
an  udder  with  four  teats  (instead  of  two)  was 
situated.  The  male  penis  was  also  present, 
but  diminutive  and  short;  its  erectores  muscles 
were  small,  and  the  prostate  gland  indistinct. 
The  urethra  was  single  as  it  left  the  bladder, 
but  it  afterwards  divided  into  two  canals,  the 
wider  of  which  opened  into  the  female  vagina 
and  vulva,  and  the  narrower  ran  through  the 
male  penis.  The  urine  passed  in  a  full  stream 
through  the  former  canal,  and  only  by  drops 
through  the  latter.  The  animal  is  alleged  to 
have  attempted  coition  in  both  ways. 

In  1829,  an  account  of  an  hermaphroditic 
goat  was  published  at  Naples,  which  is  said  to 
have  been  provided  with  both  female  ovaries 
and  male  testicles.f  The  two  ovaries  occupied 
their  usual  situation  ;  no  Fallopian  tubes  were 
found  ;  but  there  were  present  a  double-horned 
uterus  with  blind  cornua,  and  a  vagina  which 
opened  externally,  as  in  the  female.  In  the 
neighbourhood  of  the  ovaries,  and  more  ex- 
ternal than  them,  two  small  testicles  were  dis- 
covered, having  two  vasa  deferentia  arising 
from  them.  The  vasa  deferentia  ran  down- 
wards to  two  corresponding  vesicular  seminales, 
that  were  placed  alongside  of  the  uterus.  In 
the  lower  angle  of  the  external  pudenda,  a 
body,  resembling  in  length  the  male  penis  more 
than  the  female  clitoris,  was  situated  :  it  was, 
as  we  have  already  had  frequently  occasion  to 
mention  in  regard  to  the  penis  in  malformed 
male  quadrupeds,  of  a  very  tortuous  or  con- 
voluted form. 

We  have  had  an  opportunity  of  examining  an 
excellent  preserved  specimen  of  double  herma- 
phroditism in  the  sow,  referable  to  the  present 
section,  which  was  met  with  some  years  ago  by 
Dr.  Knox,  and  we  have  his  permission  to  state 
here  the  following  particulars  of  the  case. 

Among  the  internal  female  organs  there  is 
present  a  natural  well-formed  double  uterus, 
provided  with  broad  ligaments  and  two  hollow 
cornua,  each  about  six  or  seven  inches  in  length. 
The  fimbriated  extremities  are  not  distinctly 
marked,  the  female  tubes  appearing  to  end 

*  Rheinisches  Mag.  zur  Erweiterung  tier  Natur- 
kunde.    Giesscn  1793.    Bd.  i.  s.  608. 

t  Brevi  ccnne  su  di  un  Neulvo  Capro;  or, 
Gurlt's  Patholo^ischen  Anatomie,  Bd.  ii.  s.  198. 


blind  at  their  upper  terminations,  as  they  have 
often  been  observed  to  do  in  similar  cases. 
The  os  uteri  opens  inferiorly  into  a  vagina, 
which  seems  normal  in  its  structure.  At  a 
short  distance  from  the  upper  extremity  of  each 
horn  of  the  uterus,  two  bodies  of  considerable 
magnitude  are  seen  lying  in  close  juxta-position. 
The  smaller  of  these  two  bodies  is  on  either 
side  about  the  size  and  shape  of  a  large  almond  ; 
and  though  internally  of  an  indeterminate 
amorphous  structure,  they  are  considered  by 
Dr.  Knox  as  answering  to  the  two  ovaries. 
The  two  larger  bodies,  which  are  placed 
between  the  supposed  ovaries  and  the  upper 
extremities  of  the  cornua  uteri,  are  most  dis- 
tinctly testicles,  as  shewn  by  their  numerous  tor- 
tuous seminiferous  tubes,  which  have  been  suc- 
cessfully filled  with  a  mercurial  injection.  They 
are  of  the  full  size  of  the  organ  in  the  adult 
male.  The  seminiferous  tubes  of  each  testicle 
terminate  in  a  vas  deferens,  which  was  injected 
from  them  ;  and  the  two  vasa  deferentia  run 
downwards  through  the  ligamenta  lata  of  the 
uterus,  and  terminate  inferiorly  in  the  upper- 
part  of  the  vagina,  thus  following  the  course 
of  those  natural  canals  in  the  female  sow  that 
we  shall  afterwards  have  occasion  to  allude  to 
at  greater  length  under  the  name  of  Gaertner's 
ducts,  and  which  Dr  Knox,  from  the  evidence 
of  the  present  case,  believes  to  be  in  reality 
typical  of  the  male  vasa  deferentia.  There  is 
no  trace  of  vesicular  seminales.  Externally 
the  vagina  opened  along  with  the  urethra  upon 
the  perinoeum,  at  a  point  lower  than  natural  in 
the  well-formed  female.  The  clitoris  in  situa- 
tion and  size  was  nearly  normal. 

The  animal  at  the  time  of  death  was  fourteen 
months  old  ;  it  was  ferocious  in  its  habits  ;  and 
it  had  been  in  vain  tried  to  be  fattened.  It  had 
repeatedly  shewn  strong  male  propensities,  and 
at  the  season  of  heat  its  vagina  is  said  to  have 
presented  the  usual  injected  appearance  ob- 
served in  the  female  sow. 

Dr.  Harlan  of  Philadelphia*  has  lately 
described  a  still  more  perfect  instance  of  dou- 
ble hermaphroditism  than  any  of  the  preceding, 
which  he  met  with  in  the  body  of  a  gibbon  or 
orang  outang,  from  the  Island  of  Borneo 
( Simla  concolor ).  This  animal  died  of  tuber- 
cular disease  in  Philadelphia  in  1826,  when  it 
was  considered  to  be  under  two  years  of  age. 
Dr.  Harlan  gives  the  following  account  of  its 
sexual  formation.  The  penis  (jig.ZO^,  a)  was 
about  one  inch  in  length,  and  subject  to  erec- 
tions ;  it  terminated  in  an  imperforate  glans  ; 
and  a  deep  groove  on  its  inferior  surface  served 
as  a  rudimentary  urethra.  This  groove  extended 
about  two-thirds  of  the  length  of  the  penis, 
the  remaining  portion  being  covered  with  a  thin 
articular  diaphanous  membrane,  which  extended 
also  across  the  vulva  (fc),  and  closed  the  external 
orifice  of  the  vagina.  The  vagina  was  rather 
large,  and  displayed  transverse  striae.  Traces 
of  the  nymphte  and  labia  externa  were  visible. 
The  meatus  urinarius  opened  beneath  the  pubis 
into  the  vagina,  but  the  urine  must  have  been 
directed  along  the  groove  of  the  penis  by  the 

*  Med.  and  Pliys.  Researches,  p.  19. 


714 


HERMAPHRODITISM. 


Fig.  304. 


External  sexual  organs  and  testicles. 

'  gg,  the  prepuce ;  hh,  the  vasa  deferentia  ;  i,  the 
anus  ;  kh,  ischiatic  protuberances. 

membrane  obstructing  the  orifice  of  the  vulva. 
The  os  tincoe  was  surrounded  by  small  globular 
glands.  The  orifice  and  neck  of  the  uterus 
admitted  a  large  probe  into  the  cavity  of  that 
organ,  which  appeared  perfect  with  all  its  ap- 
pendages. The  round  and  broad  ligaments, 
together  with  well-developed  ovaries  (jig.  305, 
b  b),  were  all  found  in  situ.     The  scrotum 


Fig.  305. 


Internal  sexual  organs  seen  from  hehind. 


d,  the  urinary  bladder  ;  ff,  rectum  j  gg,  broad 
ligaments ;  cc,  Fallopian  tubes. 


(fig.  304,  c)  was  divided,  and  consisted  of  a 
sac  on  each  side  of  the  labia  externa,  at  the 
base  of  the  penis,  covered  with  hair.  The 
testicles  (fig.  304,  d  d)  lay  beneath  the  skin  of 
the  groin  about  two  inches  from  the  symphysis 
pubis,  obliquely  outwards  and  upwards :  they 
appeared  to  be  perfectly  formed  with  the  epi- 
didymis (J[f),  &c.  The  most  accurate  examina- 
tion could  not  discover  vesiculae  seminales  ;  but 
an  opening  into  the  vagina,  above  the  meatus 
urinarius,  appeared  to  be  the  orifice  of  the  vas 
deferens.  In  all  other  respects  the  male  and 
female  organs  of  generation  were  in  this  animal 
as  completely  perfected  as  could  have  been 
anticipated  in  so  young  an  individual,  and 
resembled  those  of  other  individuals  of  a 
similar  age. 

Two  imperfect  instances  are  on  record  of  the 
co-existence  of  male  testicles  and  female  ovaries 
in  the  human  subject. 

a.  The  first  of  these  cases  is  detailed  by 
Schrell.*  It  occurred  in  an  infant  who  died 
when  nine  months  old.  All  the  internal  and 
external  male  organs  were  present  and  perfectly 
formed,  with  the  exception  of  the  prepuce  of  the 
penis,  which  seemed  divided  in  front  and  rolled 
up.  At  the  root  of  the  large  penis,  was  a  small 
vulva  or  aperture  capable  of  admitting  a  pea, 
and  provided  with  bodies  having  an  appearance 
of  labia  and  nymphse.  This  vulva  led  into  a 
vagina  that  penetrated  through  the  symphysis 
pubis,  and  terminated  in  a  nipple-like  body  or 
imperfect  uterus,  to  which,  structures  having  a 
resemblance  to  the  Fallopian  tubes  and  ovaries 
were  attached. 

b.  The  other  and  still  more  doubtful  case  of 
the  alleged  existence  of  both  testicles  and 
ovaries  in  the  human  subject,  was  first  pub- 
lished by  Beclard.f  The  case  was  met  with 
by  M.  Laumonier  of  Rouen,  who  injected  and 
dissected  the  sexual  parts,  and  deposited  them 
in  a  dried  state,  along  with  a  wax  model  repre- 
senting them  in  their  more  recent  condition,  in 
the  Museum  of  the  School  of  Medicine  at 
Paris.  In  the  wax  model  two  female  ovaries 
with  an  uterus,  vagina,  external  vulva,  and 
large  imperforate  clitoris,  are  seen  combined 
with  two  male  testicles,  the  vasa  deferentia  of 
which  terminate  in  the  uterus  at  the  place  at 
which  the  round  ligaments  are  normally  situ- 
ated ;  these  ligaments  themselves  are  wanting. 
The  preparation  of  the  dried  sexual  parts  is  far 
from  being  equally  satisfactory,  and,  in  its 
present  imperfect  condition  at  least,  does  not 
bear  out  by  any  means  the  complete  double  her- 
maphroditic structure  delineated  in  the  model. 

III.  HERMAPHRODITISM  AS  MANIFESTED  IN 
THE  GENERAL  CONFORMATION  OF  THE  BODY, 
AND  IN  THE  SECONDARY  SEXUAL  CHARAC- 
TERS. 

In  the  preceding  observations  we  have  prin- 
cipally confined  ourselves  to  the  description  of 
hermaphroditic  malformations  as  seen  in  the 
resemblance  in  appearance  and  structure  of  the 

*  Schenk's  Medic.  Chirurg.  Archiv.  Bd.  i.  s. 
t  Bullet,  de  la  Fac.  de  Med.  1815,  p.  284 ;  or, 
Diet,  des  Sc.  Med.  x.\i,  p.  111. 


HERMAPHRODITISM. 


715 


external  genital  parts  of  one  sex  to  those  of  the 
other,  and  in  the  different  degrees  and  varieties 
of  reunion  or  co  existence  of  the  reproductive 
organs  of  the  two  sexes  upon  the  body  of  the 
same  individual.  Hermaphroditism,  however, 
may  appear  not  only  in  what  are  termed  the 
primary  sexual  parts  or  characters,  or,  in  other 
words,  in  the  organs  more  immediately  subser- 
vient to  copulation  and  reproduction,  but  it 
may  present  itself  also  in  the  secondary  sexual 
characters,  or  in  those  distinctive  peculiarities 
of  the  sexes  that  are  found  in  other  individual 
parts  and  functions  of  the  economy,  as  well  as 
in  the  system  at  large.  We  have  occasionally 
an  opportunity  of  observing  some  tendency  to 
an  hermaphroditic  type  in  the  general  system, 
without  there  being  any  very  marked  corre- 
sponding anormality  in  the  sexual  organs  them- 
selves, but  it  rarely  happens  that  there  exists 
any  hermaphroditic  malformation  of  the  primary 
organs  of  generation,  without  there  being  con- 
nected with  it  more  or  less  of  an  hermaphrodi- 
tic type  in  the  secondary  sexual  characters ; 
and  this  circumstance  often  offers  us,  in  indivi- 
dual doubtful  cases,  a  new  and  perplexing 
source  of  fallacy  in  our  attempts  to  determine 
the  true  or  predominating  sex  of  the  malformed 
individual.  Before,  however,  describing  that 
variety  of  hermaphroditism  which  manifests 
itself  in  the  general  system  and  in  the  secon- 
dary sexual  peculiarities,  it  will  be  necessary, 
in  order  to  understand  its  nature  and  origin,  to 
premise  a  few  remarks  on  the  dependence  and 
relation  of  these  secondary  characters  upon  the 
normal  and  abnormal  conditions  of  the  primary 
sexual  organs. 

That  the  various  secondary  sexual  peculiari- 
ties which  become  developed  at  the  term  of 
puberty  are  intimately  dependent  upon  the 
changes  that  take  place  at  the  same  period  in 
the  organism  of  the  female  ovaries  and  male 
testicles,  seems  proved  by  various  considera- 
tions, particularly  by  the  effect  produced  by 
original  defective  development  and  acquired 
disease  in  these  parts,  and  by  the  total  removal 
of  them  from  the  body  by  operation.  In  consi- 
dering this  point  we  shall  speak  first  of  the 
effects  of  the  states  of  the  ovaries  upon  the 
female  constitution,  and  shall  then  consider 
those  of  the  testicles  upen  the  male. 

When  the  usual  development  of  the  ovaries  at 
the  term  of  puberty  does  not  take  place,  the  se- 
condary sexual  characters  which  are  naturally 
evolved  in  the  female  at  that  period  do  not  pre- 
sent themselves;  and  this  deficiency  sometimes 
occasions  an  approach  in  various  points  to  the 
male  formation.  Thus  in  a  case  recorded  by 
Dr.  Pears,*  of  a  female  who  died  of  a  pectoral 
affection  at  the  age  of  twenty-nine,  the  ovaries 
on  dissection  were  found  rudimentary  and  in- 
distinct, and  the  uterus  and  Fallopian  tubes 
were  present,  but  as  little  developed  as  before 
puberty.  This  individual  had  never  menstru- 
ated nor  shewed  any  signs,  either  mental  or 
corporeal,  of  puberty.  The  mammas  and  nip- 
ples were  as  little  developed  as  those  of  the 
male  subject.    She  had  ceased  to  grow  at  ten 

*  Phil.  Trans,  for  1805,  p.  225. 


years  of  age,  and  attained  only  the  height  of 
four  feet  six  inches. 

In  another  analogous  instance  observed  by 
Renauldin,*  scarcely  any  rudiments  of  the 
ovaries  existed,  and  the  body  of  the  uterus  was 
absent,  but  the  external  genital  female  organs 
were  well  formed.  The  individual  who  was 
the  subject  of  this  defective  sexual  development 
had  never  menstruated  ;  the  mamma  were  not 
evolved ;  in  stature  she  did  not  exceed  three 
and  a  half  French  feet;  and  her  intellect  was 
imperfectly  developed. 

In  reference  to  these  and  other  similar  in- 
stances that  might  be  quoted,!  it  may  be  ar- 
gued that  they  do  not  afford  any  direct  evidence 
of  the  evolution  of  the  sexual  characters  of  the 
female  depending  upon  that  of  the  ovaries,  as 
the  arrestment  in  the  development  of  both  may 
be  owing  to  some  common  cause  which  gives 
rise  at  the  same  time  to  the  deficiency  in  the 
development  of  the  genital  organs,  and  to  the 
stoppage  of  the  evolution  of  the  body  in  gene- 
ral. That  the  imperfection,  however,  in  the 
organism  of  the  ovaries  may  have  acted  in  such 
cases  as  the  more  immediate  cause  or  precedent 
of  the  imperfection  or  non-appearance  of  the 
secondary  characters  of  the  sex,  seems  to  be 
rendered  not  improbable,  in  regard  to  some,  if 
not  to  all  the  instances  alluded  to,  by  the  fact 
that  the  removal  of  these  organs  before  the 
period  of  puberty,  as  is  seen  in  spayed  female 
animals,  entails,  upon  the  individuals  so  treated, 
the  same  neutral  state  of  the  general  organiza- 
tion as  was  observed  in  the  above  instances ; 
or,  in  other  words,  we  have  direct  evidence  that 
the  alleged  effect  is  capable  of  being  produced 
by  the  alleged  cause ;  and  further,  when  in 
cases  of  operation  or  disease  after  the  period  of 
puberty,  both  ovaries  have  happened  to  be  de- 
stroyed, and  their  influence  upon  the  system 
consequently  lost,  the  distinctive  secondary 
characteristics  of  the  female  have  been  observed 
also  to  disappear  in  a  greater  or  less  degree. 

Thus  in  the  well-known  case  recorded  by 
Mr.  Pott, %  the  catamenia  became  suppressed, 
the  mammae  disappeared,  and  the  body  be- 
came thinner  and  more  masculine,  in  a  healthy 
and  stout  young  woman  of  twenty-three  years 
of  age,  whose  two  ovaries  formed  hernial  tu- 
mours at  the  inguinal  rings,  and  were,  in  con- 
sequence of  their  incapacitating  the  patient 
from  work,  both  removed  by  operation. 

Many  facts  seem  to  show  that  the  act  of 
menstruation  most  probably  depends  upon 
some  periodical  changes  in  the  ovaries,  if  not, 
as  Dr.  Lee§  supposes,  in  the  Graafian  vesicles 
of  these  organs;  and  when  the  function  be- 
comes suddenly  and  permanently  stopped  in  a 

*  Seances  de  l'Acad.  Roy.  de  Med.  28  Fevrier 
1826,  and  Medical  Repository  for  1826',  p.  78. 

t  Davis,  in  his  Principles  and  Practice  of  Obste- 
tric Medicine,  p.  513,  refers  to  several  instances  in 
point.  We  may  mention  that  Dr.  Haighton  found 
that  after  the  Fallopian  tubes  were  divided  in  rab- 
bits, the  ovaries  became  gradually  atrophied,  and 
the  sexual  feelings  were  lost.  Phil.  Trans,  for 
1797,  p. 173. 

t  Surgical  Works,  vol.  iii.  p.  329. 

§  Article  Ovarv  in  Cyclo.  of  Pract.  Med. 


716 


HERMAPHRODITISM. 


woman  at  the  middle  period  of  life,  without 
any  indications  of  the  catamenial  fluid  being 
merely  mechanically  retained,  we  may  perhaps 
suspect  with  reasonable  probability  the  exist- 
ence of  a  diseased  state  which  has  destroyed 
either  successively  or  simultaneously  the  func- 
tions of  both  ovaries.  In  such  a  case  the  dis- 
tinctive secondary  peculiarities  of  the  female 
sex  come  to  give  place  to  those  of  the  male. 
Thus  Vaulevier  mentions  an  instance  in  which 
menstruation  suddenly  ceased  in  a  young  and 
apparently  healthy  woman ;  no  general  or  local 
disease  followed  ;  but  soon  afterwards  a  perfect 
beard  began  to  grow  upon  her  face.*  Again, 
in  women  who  have  passed  the  period  of  their 
menstrual  and  child-bearing  life,  and  in  whom 
consequently  the  functions  and  often  the  healthy 
structure  of  the  ovaries  are  lost  or  destroyed,  we 
have  frequently  an  opportunity  of  observing  a 
similar  tendency  towards  an  assumption  of 
some  of  the  peculiarities  of  the  male ;  an  in- 
crease of  hair  often  appears  upon  the  face,  the 
mamma?  diminish  in  size,  the  voice  becomes 
stronger  and  deeper  toned,  the  elegance  of  the 
female  form  and  contour  of  body  is  lost,  and 
frequently  the  mind  exhibits  a  more  determined 
and  masculine  cast.  Women,  both  young 
and  aged,  with  this  tendency  to  the  male  cha- 
racter, are  repeatedly  alluded  to  by  the  Roman 
authors  under  the  name  of  viragines  ;  and  Hip- 
pocrates f  has  left  us  the  description  of  two 
well-marked  instances. 

Among  the  females  of  the  lower  animals  a 
similar  approach  to  the  male  character  in  the 
general  system  not  unfrequently  shows  itself 
as  an  effect  both  of  disease  and  malformation 
of  the  sexual  organs,  and  also  in  consequence 
of  the  cessation  of  the  powers  of  reproduction 
in  the  course  of  advanced  age.  Female  deer 
are  sometimes  observed  to  become  provided  at 
puberty  with  the  horns  of  the  stag,!  and  such 

*  Journ.  de  Med.  torn.  lxix.  and  Meckel  in  Reil's 
Arch.  Bd.  xi.  s.  275.  Meckel  quotes  other  similar 
cases  from  Seger  in  Ephem.  Nat.  Cur.  Dec.  i. 
Ann.  ix.  and  x.  obs.  95;  Vicat,  sur  la  Plique 
Polonaise,  in  Murray's  Pr.  Bibl.  Bd.  i.  s.  578.'; 
and  Schurig's  Parthenologia,  p.  184.  Burlin  pub- 
lished an  express  treatise  on  the  subject,  De  barba 
mulierum  ex  menstruorum  suppressione,  Altorf. 
1664.  See  also  Haller's  Elem.  Phys.  torn.  v.  p. 
32 ;  Reuss,  Repert.  Comment,  torn.  x.  p.  205 ; 
Eble,  Die  Lehre  von  den  Haaren  in  der  organischen 
Natur.  Bd.  ii.  s.  222.  Vien.  1831  ;  and  Mehliss, 
Ueber  Virilescenz  und  Rejuvenescenz  thierischer 
Korper.  Leipz.  1838,  who  quotes  several  cases 
additional  to  those  of  Meckel. 

*  De  Morb.  Vulg.  lib.  vi.  ss.  55,  56.  "  Abderus 
Phaetusa,  Pythei  conjunx,  antea  per  juventam 
fcecunda  erat ;  viro  autem  ejus  exortante,  dinar- 
ticulos  exorti  sunt.  Quae  ubi  contigerunt,  turn  cor- 
pus virile,  turn  in  universum  hirsutum  est  reddi- 
tum,  barbaque  est  enata,  et  vox  aspera  reddita. 
Sed  cum  omnia  quae  ad  menses  deducendos  facerent 
tentassemus,  non  profluxerunt,  verum  hand  ita 
multo  post  vita  funcla  est.  Idem  quoque  in  Thaso 
Namysiae,  Gorgippi  conjugi,  contigit."  Hippocr. 
Op.  ed.  Foesii,  p.  1201. 

%  Camden's  Angl.  Norm.  (1603)  p.  821.  Lan- 
celot Eph.  Nat.  Cur.  Dec.  i.  ann.  ix  and  x.  obs. 
88.  Ridinger's  Abbild.  Seltener  Thiere  Taf.  79,  or 
Meckel  in  Reil's  Archiv.  fur  die  Physiol.  Bd.  xi. 
p.  273. 


animals  are  generally  observed  to  be  barren,* 
probably  in  consequence  either  of  a  congenital 
or  acquired  morbid  condition  of  their  ovaries 
or  other  reproductive  organs.  In  old  age,  also, 
after  the  term  of  their  reproductive  life  has 
ceased,  female  deer  sometimes  acquire  the 
horns  of  the  male  in  a  more  or  less  perfect  de- 
gree ;f  and  Burdach  alleges  that  roes  sometimes 
become  provided  with  short  horns  when  they 
are  kept  from  the  male  during  the  rutting  sea- 
son, and  at  the  same  time  furnished  with  abun- 
dant nourishment.!  Mehliss  §  alludes  to  two 
cases  in  which  a  virilescent  type  was  shewn 
principally  in  the  hair  of  the  female  deer.  In 
one  of  these  instances  the  hair  of  the  head, 
neck,  and  abdomen,  the  shape  of  the  ears  and 
extremities,  and  the  odour  of  the  animal,  gave 
it  the  closest  resemblance  to  the  male,  and  it 
followed  the  other  females  as  if  urged  by  sexual 
desire. 

This  kind  of  acquired  hermaphroditism  in 
aged  females  has,  however,  been  more  fre- 
quently and  carefully  attended  to  as  it  occurs 
in  Birds  than  as  met  with  among  the  Mamma- 
lia, the  change  to  virilescence  in  the  former 
being  more  marked  and  striking  than  in  the 
latter,  owing  to  the  great  difference  which  gene- 
rally exists  between  the  plumage  of  the  male 
and  female. ||  When  old  female  birds  live  for 
any  considerable  period  after  their  ovaries  have 
ceased  to  produce  eggs,  they  are  usually  ob- 
served to  assume  gradually  more  or  less  of  the 
plumage  and  voice,  and  sometimes  the  habits 
also  of  the  male  of  their  own  species.  This 
curious  fact,  first  pointed  out  by  Aristotle  U  in 
relation  to  the  domestic  fowl,  has  now  been 
seen  to  occur  in  a  number  of  other  species  of 
birds,  but  particularly  among  the  Gallinaceae. 
It  has  been  in  modern  times  remarked  in  the 
common  fowl  ( P/iasianus  gallus )  by  Tucker, 
Butler,  and  Jameson;  in  the  common  pheasant 
(P.  colchicus )  by  Hunter  and  Isidore  St. 
Hilaire ;  in  the  golden  pheasant  (P.  pictus) 
by  Blumenbach  and  St.  Hilaire  ;  in  the  silver 
pheasant  (P.  ni/chemerus )  by  Bechstein  and 
St.  Hilaire ;  in  the  turkey  ( Meleagris )  by 
Bechstein  ;  in  the  pea-hen  ( Pavo )  by  Hunter 
and  Jameson  ;  and  in  the  partridge  ( Tetrao 
perdnx )  by  Montagu  and  Yarrell.  Among 
the  Cursores  it  is  mentioned  as  having  occurred 
in  the  bustard  ( Otis)  by  Tiedemann,  and  in 
the  American  pelican  ( Platalea  aiaia)  by 
Catesby.  In  the  order  Palmipeds  it  has  been 
observed  by  Tiedemann  and  Rumball  in  the 

*  Wildungen,  Taschenbuch  fiir  Forst-  und  Jagd- 
freunde,  s.  17. 

t  Otto's  Path.  Anat.  by  South,  p.  166,  s.  123, 
n.  18,  for  list  of  cases. 

t  Phys.  vol.  i.  §  183,  p.  318. 

§  Ueber  Virilescenz  Thierisch.  Koerper ;  or 
British  and  Foreign  Med.  Review,  vol.  vi.  p.  77. 

||  It  occurs  also  more  frequently  among  birds 
than  among  mammalia,  from  the  former  possessing 
only  a  single  ovary. 

%  "  Gallini,  cum  vicerint  gallos,  concurrunt  ma- 
resque  imitandi  subagitare  conantur.  Attollitur 
etiam  crista  ipsis,  simul  et  clunes  (uropygium)  ; 
adeo  ut  jam  non  facile  diagnoscantur  an  fceminae 
sint.  Quibusdam  etiam  calcaria  parva  surrigun- 
tur."    Hist.  Animal,  lib.  ix.  cap.  36. 


HERMAPHRODITISM. 


717 


domestic  and  wild  duck  f Anas  boscha ). 
Among  the  Scansores  it  has  been  seen  in  the 
cuckoo  ( Cuculus  canorus )  by  Payraudeau ; 
and  among  the  Passeres  in  the  cotinga  ( Am- 
pelis )  by  Dufresne  ;  in  the  chaffinch  ( Frin- 
gilla  J  and  rougequeue  (  Motacilla )  by  Prevost ; 
and  in  the  bunting  ( Ember iza  paradisaa  and 
longicauda )  by  Blumenbach. 

This  change  of  plumage  in  old  female  birds 
commences,according  to  M.Isidore  St.Hilaire,* 
much  sooner  in  some  instances  than  in  others ; 
it  may  only  begin  to  show  itself  several  years 
after  the  bird  has  ceased  to  lay,  though  depend- 
ing more  or  less  directly  upon  this  phenomenon, 
and  sometimes  it  commences  immediately  after 
it.  The  change  may  be  effected  in  a  single 
season,  though  in  general  it  is  not  complete  for 
some  years.  When  it  is  perfected,  the  female 
may  display  not  only  the  variety  of  colours,  but 
also  the  brilliancy  of  the  male  plumage,  which 
it  sometimes  resembles  even  in  its  ornamental 
appendages,  as  in  the  acquisition  of  spurs,  and, 
in  the  domestic  fowls,  of  the  comb  and  wattles 
of  the  cock.  The  voice  of  the  bird  is  also  very 
generally  changed.  Its  female  habits  and  in- 
stinct are  likewise  often  lost ;  and,  in  some  in- 
stances, it  has  been  seen  to  assume  in  a  great 
degree  those  of  the  male,  and  has  even  been 
observed  to  attempt  coition  with  other  females 
of  its  own  species  f  In  most  of  the  female 
birds  that  have  undergone  this  change,  the 
ovary  has  been  found  entirely  or  partially  dege- 
nerated, though  in  a  few  cases  the  morbid  alte- 
ration is  not  very  marked,  eggs  having  even 
been  present  in  the  organ  in  one  or  two  in- 
stances. In  general,  however,  it  is  greatly 
diminished  in  size,  or  has  become  altogether 
atrophied  ;  but  the  perfection  of  the  change  in 
the  plumage  does  not  seem  to  bear  any  direct 
ratio  with  the  degree  of  morbid  alteration  and 
atrophy  in  the  ovary. 

That  the  changes  towards  the  male  type,  de- 
scribed as  occasionally  occurring  in  old  female 
birds,  is  directly  dependent,  not  upon  their  age, 
but  upon  the  state  of  the  ovaries  in  them, 
seems  still  further  proved  by  similar  changes 
being  sometimes  observed  in  these  females  long 
previous  to  the  natural  cessation  of  the  powers 
of  reproduction,  in  consequence  of  their  ovaries 
having  become  wasted  or  destroyed  by  disease. 
Greve,^  in  his  Fragments  of  Comparative 
Anatomy  and  Physiology,  states  that  hens 
whose  ovaries  are  scirrhous  crow  sometimes 
like  cocks,  acquire   tail-feathers  resembling 


*  Edinburgh  Journ.  of  Philosoph.  Science,  (1826") 
p.  308. 

t  Rumball,  in  Home's  Comparative  Anatomy, 
vol.  iii.  p.  330,  states  having  observed  an  old  duck 
which  had  assumed  the  male  plumage,  attempt 
sexual  connection  with  another  female.  This  may 
perhaps  enable  us  to  understand  the  reputed  cases 
of  hermaphroditism  in  women,  who,  as  related  by 
Mollerus  (Tract,  de  Hermaphr.  cap.  ii.)  and  Blan- 
card,  (Collect.  Medico-Phys.  cent.  iii.  obs.  80,) 
after  having  themselves  borne  children  became  ad- 
dicted to  intercourse  with  other  females.  Of  course 
we  cannot  give  our  credence  to  the  alleged  success- 
ful issue  of  such  intercourse. 

t  Bruchstuccke  sur  vergleich.  Anat.  und  Phvsiol. 
s.  45. 


those  of  the  male,  and  become  furnished  with 
large  spurs.  The  same  author  mentions  also 
the  case  of  a  duck,  which,  from  being  previously 
healthy,  suddenly  acquired  the  voice  of  the 
male,  and  on  dissection  its  ovary  was  found 
hard,  cartilaginous,  and  in  part  ossified. 

Mr.  Yarrell,  in  a  paper  read  before  the  Royal 
Society  in  1827,*  has  stated  that  in  a  number 
of  instances  he  had  observed  young  female 
pheasants  with  plumage  more  or  less  resem- 
bling the  male,  and  in  all  of  them  he  found  on 
dissection  the  ovaries  in  a  very  morbid  state, 
and  the  oviduct  diseased  throughout  its  whole 
length,  with  its  canal  obliterated  at  its  upper 
part.  He  also  shews  that  a  similar  effect  upon 
the  secondary  sexual  characters  of  the  female 
bird  is  produced  by  the  artificial  division  and 
removal  of  a  small  portion  of  their  oviduct  in 
the  operation  of  making  capons  of  female  poul- 
try ;  and  he  states  that  his  investigations  have 
led  him  to  believe  that  in  all  animals  bearing 
external  characters  indicative  of  the  sex,  these 
characters  will  undergo  a  change  and  exhibit 
an  appearance  intermediate  between  the  perfect 
male  and  female,  wherever  the  system  is  de- 
prived of  the  influence  of  the  true  sexual  organs, 
whether  from  original  malformation,  acquired 
disease,  or  artificial  obliteration  ,f 

From  the  frequency  with  which  castration  is 
performed,  the  effects  of  the  testicles  in  evol- 
ving the  general  sexual  peculiarities  of  the  male 
have  been  more  accurately  ascertained  than 
those  of  the  ovaries  upon  the  female  consti- 
tution. These  effects  vary  according  to  the  age 
at  which  the  removal  of  the  testicles  takes 
place.  When  an  animal  is  castrated  some  time 
before  it  has  reached  the  term  of  puberty,  the 
distinctive  characters  of  the  male  are  in  general 
never  developed ;  and  the  total  absence  of  these 
characters,  together  with  the  softness  and  re- 
laxation of  their  tissues,  the  contour  of  their 
form,  the  tone  of  their  voice,  and  their  want 
of  masculine  energy  and  vigour,  assimilate 
them  more  in  appearance  and  habits  to  the 
female  than  to  the  male  type.  If  the  testicles 
are  removed  nearer  the  period  of  puberty,  or 
at  any  time  after  that  term  has  occurred,  and 


*  Phil.  Trans,  for  1827,  part  ii.  p.  268. 

t  On  old  or  diseased  female  birds  assuming  the 
plumage,  &c.  of  the  male,  see  J.  Hunter,  Observ. 
on  the  An.  Econ.  p.  75;  E.  Home,  Lect.  on  Comp. 
Anat.  vol.  iii.  p.  329;  Mauduit,  in  Encycl.  Method. 
Art.  Fuisan,  torn.  'ii.  p.  3  ;  Butter,  in  Wernerian 
Soc.  Mem.  vol.  iii.  p.  183  ;  Schneider's  Notes,  in 
his  edition  of  the  Emperor  Frederick  the  Second's 
Treatise  "  De  Arte  Venandi  cum  Avibus;"  Tucker's 
Ornithologia  Damnoniensis  ;  Catesby's  Natural 
History  of  Carolina,  &c.  i.  t.  1.  ;  Bechstein, 
Naturgeschichte  d.  Deutschlands,  bd.  ii.  §  116; 
Blumenbach,  De  anomalis  et  vitiosis  quibusdam 
nisus  formativi  aberrationibus,  p.  8  ;  and  Instit.  of 
Physiology,  p.  369;  Payrandeau,  Bull,  des  Sc. 
Nat.  t.  xiii.  p.  243 ;  Tiedemann,  Zoologie,  vol. 
iii.  p.  306  ;  Geoff.  St.  Hilaire,  Phil.  Anat.  torn.  ii. 
p.  360  ;  Isid.  St.  Hilaire,  Mem.  du  Mus.  d'Hist.  Nat. 
torn.  xii.  p.  220  ;  Annal.  des  Sc.  Nat.  t.  vii.  p.  336, 
or  Edinburgh  New  Philosophical  Journal  for  1826, 
p.  302,  with  additional  cases  by  Professor  Jameson, 
p.  309 ;  Kob,  De  mutatione  sexus,  p.  11.  Berlin, 
1823  ;  Yarrell,  Phil.  Trans,  for  1827,  p.  268,  with 
a  drawing  of  the  diseased  ovaries,  &c. 


718 


HERMAPHRODITISM. 


when  the  various  male  sexual  peculiarities  have 
been  already  developed,  the  effect  is  seldom 
so  striking;  the  sexual  instincts  of  the  animal, 
and  the  energy  of  character  which  these  in- 
stincts impart,  are  certainly  more  or  less  com- 
pletely destroyed,  and  the  tone  of  the  voice  is 
sometimes  changed  to  that  of  puberty ;  but  the 
general  male  characteristics  of  form,  such  as 
the  beard  in  man,  and  the  horns  in  the  Ru- 
minantia,  most  commonly  continue  to  grow. 
In  animals,  such  as  the  stag,  which  possess 
deciduous  horns,  the  removal  of  the  testicles 
during  the  rutting  season  causes  the  existing 
horns  to  be  permanent;  and  if  the  operation  is 
performed  in  an  adult  animal  when  out  of  heat, 
no  new  horns  in  general  appear.*  In  the  ox, 
the  effect  of  castration  upon  the  growth  of  the 
horns,  even  when  performed  before  the  time 
of  puberty,  is  quite  remarkable ;  for  instead  of 
having  their  development  altogether  stopped, 
or  their  size  at  least  diminished  by  the  opera- 
tion, as  occurs  in  the  ram  and  stag,  the  volume 
of  these  appendages  is  even  increased  by  the 
operation,  the  horns  of  the  ox  being  generally 
larger  but  less  strong  than  those  of  the  entire 
bull.  Castration  in  the  boar  causes,  according 
to  Greve,f  the  tusks  to  remain  small,  and  pre- 
vents altogether  the  replacement  of  the  teeth. 
This  author  also  states  that  the  same  operation 
on  the  horse  prevents  the  full  development  of 
the  neck,  renders  the  teeth  smaller  and  slower 
in  their  growth,  increases  the  growth  of  the 
hair,  and  the  size  of  the  horny  protuberances 
on  the  inside  of  the  legs.  The  prostate  gland, 
he  further  alleges,  as  well  as  the  vesiculae  se- 
minales,  become  augmented  as  much  as  a 
third  in  their  volume  in  consequence  of  the 
operation  .J 

The  removal  of  the  testicles  both  before  and 
after  the  period  of  puberty  commonly  gives 
rise  to  another  singular  effect,- — to  an  increased 
deposition  of  fat  over  the  body,  as  has  already 
been  mentioned  in  the  article  Adipose  Tissue, 
and  from  this  circumstance  the  general  form 
of  the  body,  and  in  man  that  of  the  mammae, 
is  sometimes  modified  in  a  degree  that  in- 
creases the  resemblance  to  the  opposite  sex. 
In  the  sterile  of  both  sexes  in  the  human  sub- 
ject an  unusual  corpulency  is  not  uncom- 
mon, and  the  same  state  is  often  met  with  in 
old  persons,  and  particularly  in  females,  after 
the  period  of  their  child-bearing  life  is  past. 

The  nature  of  the  effects  produced  by  the 
existence  and  functional  activity  of  the  testicles 
and  ovaries  upon  the  development  of  the  se- 
condary sexual  characters  of  the  male  and 
female,  may  be  further  illustrated  by  what 
occurs  in  the  season  of  heat  to  animals  such 
as  the  deer,  sheep,  birds,  &c.  that  have  peri- 
odical returns  of  the  sexual  propensity.  At  these 
periods  all  the  distinctive  general  characters 
of  the  sexes  become  much  more  prominently 
developed,  in  conjunction  with,  and  apparently 
in  consequence  of,  the  changes  which  have 

*  Buffon,  Hist.  Nat.  torn.  vi.  p.  80. 
t  Bruchstuecke  zur  Vergl.  Anat.  und  Physiol, 
p.  41. 
t  Loc.  cit.  p.  45. 


been  ascertained  by  observation  to  occur  at  that 
time  in  the  relative  size  and  activity  of  the  in- 
ternal organs  of  generation.  Thus  with  the 
return  of  the  season  of  sexual  instinct  the 
dorsal  crests  and  cutaneous  ear-lobes  of  tritons 
enlarge;  in  Batrachian  Reptiles  the  spongy 
inflations  of  the  thumbs  become  increased  in 
size ;  the  various  species  of  singing  birds  re- 
acquire their  vocal  powers ;  and  some,  as  the 
cuckoo  and  quail,  appear  capable  of  exercising 
their  voice  only  at  this  period  of  the  year. 
At  the  pairing  season  also  the  plumage  of  birds 
becomes  brighter  in  tint,  and  in  some  instances 
is  in  other  respects  considerably  changed,  as 
in  the  male  ruff  (  Tringa  pugnax),  who  then 
reassumes  the  tuft  of  feathers  upon  his  head 
and  neck,  and  the  red  tubercles  upon  his  face 
that  had  fallen  oft'  during  the  moulting,  and 
thus  left  him  more  nearly  allied  in  appearance 
to  the  female  during  the  winter.  In  reference 
to  this  subject,  it  appears  to  us  interesting  to 
remark,  that  in  certain  birds,  as  in  the  different 
species  of  the  genus  Fringilla,  the  male  pre- 
sents in  winter  a  plumage  very  similar  to  that 
of  the  female,*  and  in  the  present  inquiry  it  is 
important  to  connect  this  fact  with  the  very 
diminutive  size  and  inactive  condition  of  the 
testicles  of  these  birds  at  that  season.  (See 
Aves.) 

From  the  remarks  that  we  have  now  made 
upon  the  influence  of  the  ovaries  and  testicles 
in  developing  the  general  sexual  peculiarities 
of  the  female  and  male,  it  will  be  easy  to  con- 
ceive that  when,  in  cases  of  malformation  of 
the  external  genital  organs  giving  rise  to  the 
idea  of  hermaphroditism,  there  is  at  the  same 
time,  as  sometimes  happens,  a  simultaneous 
want  of  development  in  the  internal  organs  of 
reproduction,  particularly  in  the  ovaries  and 
testicles,  the  general  physical  and  moral  pecu- 
liarities distinctive  of  the  sex  of  the  individual 
may  be  equally  deficient,  or  have  a  tendency 
even  to  approach  in  more  or  fewer  of  their 
points  to  those  of  the  opposite  sexual  type. 
In  this  way  we  may,  it  is  obvious,  have  general 
or  constitutional  hermaphroditic  characters,  if 
they  may  be  so  termed,  added  to  those  al- 
ready existing  in  the  special  organs  of  gene- 
ration, and  rendering  more  difficult  and  com- 
plicated the  determination  of  the  true  sex  of 
the  malformed  individual.  Some  cases  of  spu- 
rious hermaphroditism  in  the  male  published 
by  Sir  E.  Homef  may  serve  to  illustrate  this 
remark. 

A  marine  soldier,  aged  twenty-three,  was 
admitted  a  patient  into  the  Royal  Naval  Hos- 
pital at  Plymouth.  He  had  been  there  only  a 
few  days,  when  a  suspicion  arose  of  his  being 
a  woman,  which  induced  Sir  Everard  to  ex- 
amine into  the  circumstances.  He  proved  to 
have  no  beard;  his  breasts  were  fully  as  large 
as  those  of  a  woman  at  that  age ;  he  was  in- 
clined to  be  corpulent;  his  skin  was  uncom- 
monly soft  for  a  man  ;  his  hands  were  fat  and 
short,  and  his  thighs  and  legs  very  much  like 
those  of  a  woman :  the  quantity  of  fat  upon 

*  Stark's  Elements  of  Nat.  Hist,  vol.i.  p.  243. 
t  Comp.  Anat.  vol.  iii.  p.  320. 


HERMAPHRODITISM. 


719 


the  os  pubis  resembled  the  mons  veneris ;  and 
in  addition  he  was  weak  in  his  intellect,  and 
deficient  in  bodily  strength.  The  external 
genital  organs  shewed  him  to  be  a  male,  but 
the  penis  was  unusually  small,  as  well  as  short, 
and  not  liable  to  erections ;  the  testicles  were 
not  larger  in  size  than  they  commonly  are  in 
the  foetal  state ;  and  he  had  never  felt  any  pas- 
sion for  the  opposite  sex. 

The  following  cases  by  the  same  author 
strongly  illustrate  this  subject.*  In  a  family  of 
three  children  residing  near  Modbury  in  De- 
vonshire, the  second,  a  daughter,  was  a  well- 
formed  female,  the  eldest  and  youngest  were 
both  malformed  males.  The  eldest  was  thir- 
teen years  of  age.  His  mons  veneris  was 
loaded  with  fat ;  no  penis  could  be  said  to  be 
present,  but  there  was  a  prseputium  a  sixth  of 
an  inch  long,  and  under  it  the  meatus  urina- 
rius,  but  no  vagina.  There  was  an  imperfect 
scrotum  with  a  smooth  surface,  there  being  no 
raphe"  in  the  middle,  but,  in  its  place,  an  in- 
dented line ;  it  contained  two  testicles,  of  the 
size  that  they  are  met  with  in  the  foetus.  His 
breasts  were  as  large  as  those  of  a  fat  woman. 
He  was  four  feet  high,  and  of  an  uncommon 
bulk,  his  body  round  the  waist  being  equal  to 
that  of  a  fat  man,  and  his  thighs  and  legs  in 
proportion.  He  was  very  dull  and  heavy,  and 
almost  an  idiot,  but  could  walk  and  talk  ;  he 
began  to  walk  when  a  year  and  a  half  old. 
The  younger  brother  was  six  years  old,  and 
uncommonly  fat  and  large  for  his  age.  He 
was  more  an  idiot  than  the  other,  not  having 
sense  enough  to  learn  to  walk  although  his 
limbs  were  not  defective. 

A  case  in  a  similar  manner  confirmatory 
of  the  preceding  remarks  is  mentioned  by  Itard 
de  Riez.f  A  young  man,  aged  twenty-three, 
had  no  testes  in  the  scrotum,  a  very  small  penis, 
not  capable  of  erection,  and  a  divided  scrotum. 
He  was  in  stature  below  the  middle  size.  His 
skin  was  soft,  smooth,  and  entirely  free  from 
hair,  the  place  of  the  beard  being  supplied  by 
a  slight  down.  The  voice  was  hoarse;  the 
muscles  were  not  well  marked  ;  the  form  of  the 
chest  resembled  that  of  the  female,  and  the 
pelvis  was  extremely  broad  and  large.  The 
intellectual  faculties  were  very  dull,  and  the 
sexual  appetite  was  entirely  wanting. 

Renauldin,  also,  in  the  same  work,]:  has  re- 
corded another  case  in  point.  In  a  soldier  of 
twenty-four  years  of  age,  whose  genital  organs 
were  extremely  undeveloped,  his  penis  being 
only  of  the  size  of  a  small  tubercle,  and  his 
testicles  not  larger  than  small  nuts,  the  pelvis 
was  broad;  the  chest  narrow;  the  face  and 
body  in  general  were  not  covered  with  hair, 
with  the  exception  of  a  small  quantity  upon 
the  pubis ;  the  voice  was  feminine,  and  the 
mammary  glands  were  as  perfectly  developed 
as  in  the  adult  female.  The  body  of  this  in- 
dividual was  rather  lean  than  otherwise.  The 

*  lb.  p.  320-21. 

t  Memoires  de  la  Soiicte  Med.  d'Emnlation, 
torn.  iii.  p.  293-5. 
t  Tom.  i.  p.  241. 


mammae  had  begun  to  enlarge  when  his  body 
attained  to  its  full  stature  at  sixteen  years  of 
age.  He  had  all  the  habits  and  sexual  desires 
of  the  male  sex. 

In  quadrupeds  as  in  man,  when  the  tes- 
ticles or  ovaries  are  imperfectly  formed,  the 
secondary  sexual  peculiarities  are  frequently 
so  defectively  evolved  as  to  offer  a  kind  of  her- 
maphroditic or  neutral  type  in  the  general  con- 
figuration and  characters  of  the  animal.  Thus, 
the  free-martin  does  not  present  an  exact 
analogy  in  form  either  with  the  bull  or  cow, 
but  exhibits  a  set  of  characters  intermediate 
between  both,  and  more  nearly  resembling 
those  of  the  ox  and  of  the  spayed  heifer.  In 
size  it  resembles  the  castrated  male  and  spayed 
female,  being  considerably  larger  than  either 
the  bull  or  the  cow,  and  having  horns  very 
similar  to  those  of  the  ox.  Its  bellow  is  simi- 
lar to  that  of  the  ox,  being  more  analogous 
to  that  of  the  cow  than  of  the  bull.  Its  flesh, 
like  that  of  the  ox  and  spayed  heifer,  is  gene- 
rally much  finer  in  its  fibre  than  the  flesh  of 
either  the  bull  or  cow,  and  is  supposed  to 
exceed  even  that  of  the  ox  and  heifer  in  deli- 
cacy of  flavour.* 

The  consideration  of  the  various  facts  that 
we  have  now  stated  inclines  us  to  believe  that 
the  natural  history  characters  of  any  species 
of  animal  are  certainly  not  to  be  sought  for 
solely  either  in  the  system  of  the  male  or  in 
that  of  the  female ;  but,  as  Mr.  Hunter  pointed 
out,  they  are  to  be  found  in  those  properties 
that  are  common  to  bolh  sexes,  and  which  we 
have  occasionally  seen  combined  together  by 
nature  upon  the  bodies  of  an  unnatural  her- 
maphrodite; or  evolved  from  the  interference 
of  art,  upon  a  castrated  male  or  spayed  female. 
In  assuming  at  the  age  of  puberty  the  distinc- 
tive secondary  peculiarities  of  his  sex,  the 
male,  as  far  as  regards  these  secondary  pecu- 
liarities, evidently  passes  into  a  higher  degree 
of  development  than  the  female,  and  leaves 
her  more  in  possession  of  those  characters  that 
are  common  to  the  young  of  both  sexes,  and 
which  he  himself  never  loses,  when  his  tes- 
ticles are  early  removed.    These  and  other 
facts  connected  with  the  evolution  of  both  the 
primary  and   secondary  peculiarities   of  the 
sexes  further  appear  to  us  to  shew  that,  phy- 
siologically at  least,  we  ought  to  consider  the 
male  type  of  organization  to  be  the  more  per- 
fect as  respects  the  individual,  and  the  female 
the   more   perfect  as   respects   the  species. 
Hence  we  find  that,  when  females  are  mal- 
formed in  the  sexual  parts  so  as  to  resemble 
the  male,  the  malformation  is  almost  always 
one  of  excessive  development,  as  enlargement 
of  the  clitoris,  union  of  the  labia,  &c. ;  and, 
on  the  other  hand,  when  the  male  organs  are 
malformed  in  such  a  manner  as  to  simulate  the 
female,  the  abnormal  appearance  is  generally 
capable  of  being  traced  to  a  defect  of  deve- 
lopment, such  as  the  want  of  closure  of  the 
perinseal  fissure,  and  of  the  inferior  part  of  the 
urethra,  diminutive  size  of  the  penis,  retention 

*  Hunter's  Obs.  on  the  An.  Econ.  p.  60. 


720 


HERMAPHRODITISM. 


of  the  testicles  in  the  abdomen,  &c.  In  the 
same  way,  when  the  female  assumes  the  secon- 
dary characters  of  the  male,  it  is  either,  first, 
when  by  original  malformation  its  own  ovaries 
and  sexual  organs  are  so  defective  in  structure 
as  not  to  be  capable  of  taking  a  part  in  the 
function  of  reproduction,  and  of  exercising 
that  influence  over  the  general  organization 
which  this  faculty  imparts  to  them;  or, 
secondly,  when  in  the  course  of  age  the  ovaries 
have  ceased  to  be  capable  of  performing  the 
action  allotted  to  them  in  the  reproductive 
process.  In  both  of  these  cases  we  observe 
the  powers  of  the  female  organization,  now 
that  its  capabilities  of  performing  its  particular 
office  in  the  continuation  of  the  species  are 
wanting  or  lost,  expend  themselves  in  perfecting 
its  own  individual  system,  and  hence  the  ani- 
mal gradually  assumes  more  or  fewer  of  those 
secondary  sexual  characters  that  belong  to  the 
male. 

We  do  not  consider  it  subversive  of  the  pre- 
ceding view  to  qualify  it  with  the  two  follow- 
ing admissions, — 1st,  that,  owing  to  the  ener- 
gies of  the  female  system  being  so  strongly 
and  constantly  directed  towards  the  reproduc- 
tive organs,  and  the  accomplishment  of  those 
important  functions  which  these  organs  have  to 
perform  in  the  economy  of  the  species,  the 
general  characters  of  the  species  may  be  de- 
veloped in  her  body  in  a  degree  less  than  they 
otherwise  would  be,  or  than  actually  consti- 
tutes the  proper  standard  of  the  species  ;  and, 
2dly,  in  consequence  of  the  peculiarities  of 
the  sexual  functions  of  the  female,  some  of 
the  individual  organs  of  her  system,  as  the 
mamma?,  are  evolved  in  a  degree  greater  than 
is  consonant  with  the  standard  characters  of  the 
species.  At  the  same  time  we  would  here 
remark  that  the  occasional  enlarged  condition 
of  the  mamma)  in  hermaphrodites  in  whom  the 
male  sexual  type  of  structure  predominates, 
(as  in  the  examples  of  spurious  male  herma- 
phrodites that  have  been  quoted  from  Sir  E. 
Home,  and  in  other  instances  mentioned  by 
Renauldin,  Julien,  Petit,  Rullier,  and  others 
in  the  human  subject,  as  well  as  in  numerous 
cases  among  hermaphrodite  quadrupeds,)  would 
almost  seem  to  shew  that  the  full  development 
of  the  mammary  glands  is  a  character  proper 
to  the  species  in  general,  rather  than  one  pecu- 
liar to  the  female  system  alone.  In  males, 
also,  who  are  perfect  in  their  reproductive 
organs  and  functions,  the  mamma?  are  some- 
times observed  to  be  developed  in  so  complete 
a  manner  as  to  be  capable  of  secreting  milk, 
forming  what  may  be  regarded  as  one  of  the 
slightest  approaches  towards  hermaphroditic 
malformation  in  the  male  organization;*  and 

*  The  secretion  of  milk  in  the  mammary  glands 
of  the  male  is  occasionally  observed  amongst  our 
domestic  quadrupeds.  See  Gurlt's  Pathologischen 
Anatomie  der  Haus-Saugthiere,  Bd.  ii.  s.  188  ; 
Blumenbach  in  the  Hanoversich  Magazin  for  1787  ; 
and  Home  in  Comp.  Anat.  iii.  p.  328.  Among 
the  recorded  instances  and  observations  upon  it  in 
man  we  may  refer  to  Paullini,  Cynographia,  p.  52  ; 
Schacher,  De  Lacte  Virorum  et  Virginum,  Leipz. 


the  mammae  of  the  infants  of  both  sexes  not 
unfrequently  contain  a  lactiform  fluid  at  birth. 

In  some  instances  of  hermaphroditic  mal- 
formation the  total  form  and  configuration  of 
the  body  have  been  alleged  to  present  not  only 
a  general  tendency  towards  the  physical  se- 
condary characters  of  the  opposite  sex,  or  to 
exhibit  in  a  permanent  state  the  neutral  con- 
dition existing  before  puberty,  but  different 
individual  parts  of  it  have  been  occasionally 
conceived  to  be  developed  after  a  different 
sexual  type.  Thus,  for  instance,  we  have  al- 
ready mentioned  in  regard  to  Hubert  Jeau 
Pierre,  that  the  upper  half  of  the  body  of  this 
individual  seemed  formed  after  the  female,  and 
the  lower  half  after  the  male  type,  the  larynx 
and  mammae  being  quite  feminine,  the  face 
shewing  no  appearance  of  beard,  and  the  arms 
being  delicate  and  finely  rounded,  while  the 
pelvis  was  narrow,  and  the  thighs  were  marked 
and  angled  as  in  man.  In  a  case  described  by 
Schneider,*  the  reverse  held  true,  the  bust 
being  male  with  a  strong  beard  and  large 
thorax,  and  the  pelvis  being  large  and  distinctly 
female.  A  more  mixed  combination  of  the 
secondary  sexual  characters  has  been  already 
described  as  existing  in  the  cases  detailed  by 
Ricco,  Mayer,  Arnaud,  Bouillaud,  &c. 

One  side  of  the  body  has  been  sometimes 
observed  to  be  apparently  formed  in  one  or 
more  of  its  parts  on  a  sexual  type  different 
from  that  of  the  same  parts  on  the  opposite 
side.  Girald,  in  his  Topography  of  Ireland,f 
mentions  a  reputed  female,  who  had  the  right 
side  of  the  face  bearded  like  that  of  a  man, 
and  the  left  smooth  like  that  of  a  woman. 
Mr.  King  J  has  described  an  interesting  in- 
stance of  hermaphroditic  malformation  in  an 
individual  whose  general  character  was  mas- 
culine, but  with  the  pelvis  large  and  wide; 
the  left  testicle  only  had  descended  into  the 
groin,  and  the  mamma  of  this  side  was  small 
comparatively  to  that  of  the  opposite  or  right 
side. 

In  a  hind  mentioned  by  Mr.  Hay,§  and 
which,  he  believed,  had  never  produced  any 
young,  one  of  the  ovaries  on  dissection  after 
death  was  found  to  be  scirrhous.  The  animal 
had  one  horn  resembling  that  of  a  three  years- 
old  stag  on  the  same  side  with  the  diseased 
ovary  ;  there  was  no  horn  on  the  opposite  side. 
Bomare||  has  given  a  similar  case  in  the  same 

1742;  Sinnibaldus,  Geneanthrop.  torn.  iv.  p.  456; 
Alex.  Benedictus,  Anatom.  Corp.  Hum.  lib.  iii. 
p.  595  ;  Winslow,  Anatomy,  vol.  ii.  p.  214  ; 
Deusing,  De  Lacte,  p.  327 ;  Kyper,  Anthropo- 
logia,  lib.  i.  p.  490;  Buffon,  Hist.  Nat.  torn.  ii. 
p.  543 ;  Bishop  of  Cork,  Phil.  Trans,  vol.  xli. 
p.  813  ;  Humboldt,  Personal  Narrative,  vol.  iii. 
p.  57  ;  Franklin,  First  Expedition  to  the  Polar 
Seas,  (London,  1823.)  p.  157. 

*  Kopp's  Jahrbuch  der  Staatsarzneikunde,  Bd.  x. 
s.  134. 

t  Topog.  Hiberniae,  in  Camden's  Angl.&c. (1603), 
part  ii.  p.  724. 

t  London  Med.  Repository  for  1820,  vol.  xiii. 
p.  87. 

4  Linnaean  Transactions,  vol.  iii.  p.  356. 
[|  Journ.  de  Phys.  torn.  vi.  p.  506. 


HERMAPHRODITISM. 


721 


animal,  where  a  single  horn  was  present,  situ- 
ated also  on  the  same  side  with  the  diseased 
and  degenerated  ovary  ;  and  Russell  *  states, 
as  the  result  of  his  experiments  on  castration 
in  the  deer,  that  when  he  removed  one  testicle 
only  from  the  animal,  the  horn  on  the  opposite 
side  was  the  more  completely  developed  of  the 
two.  Azaraf  observed  in  two  birds  the  right 
side  of  the  tail  to  possess  the  characters  of  the 
male,  and  the  left  those  of  the  female. 

In  the  hermaphroditic  lobster  previously  al- 
luded to  as  described  by  Nicholls,  the  general 
external  configuration  of  the  body  was,  like 
that  of  the  sexual  organs,  perfectly  female  on 
one  side,  and  perfectly  male  on  the  other. 

It  is  principally,  however,  among  herma- 
phroditic insects  that  a  difference  of  sexual 
type  in  the  general  conformation  of  the  oppo- 
site sides  of  the  body,  and  of  its  individual 
parts,  has  been  observed  ;  and  this  malforma- 
tion is  the  more  striking  and  easy  of  obser- 
vation in  this  class  of  animals,  on  account  of 
the  great  differences  in  colour,  size,  and  form 
respectively  presented  by  the  antenna;,  wings, 
and  other  pai  ts  of  the  body  of  the  males  and 
females  of  the  same  species. 

Lateral  hermaphroditism  of  the  body  in  In- 
sects has  been  most  frequently  observed  by 
Entomologists  amongst  the  class  Lepidoptera. 
It  has  now  been  remarked  in  the  following 
species: — in  the  Argynnis  papliia,  Lycana 
alexis,  Saturnia  pyri,  Endromis  versicolor,  and 
Hurpya  vinula  (Ochsenheimer) ;  in  the  Gas- 
trophaga  medicaginis  and  Lycana  adonis 
(Rudolphi) ;  in  the  Liparis  dispur  (Schaefer, 
Ochsenheimer,  and  Rudolphi);  in  the  Sa- 
turnia Carpini  (Capieux,  Ochsenheimer,  and 
Rudolphi);  in  iheOrastrophagaquercifblia  (Hett- 
linger  and  Rudolphi);  in  the  Gastrophaga  pini 
(Scopoli);  in  the  Gastrophaga  cratagi  (Esper); 
in  the  Sphinx  convolvuli  (Ernst);  Sphinx populi 
(Fischer  and  Westwood) ;  Papilio  polycaon 
(Macleay);  Polyonimatus  alexis  (Entomolog. 
Mag.  vol.  iii.  p.  304);  Bombyx  castrensis 
(Duval) ;  in  the  Argynnis  paphia  (Allis) ; 
in  the  Vanessa  atalanta  (Schrank  and  Germar); 
and  in  the  Vanessa  antiopha  and  Deilephila 
euphorbia  (Germar).  King  and  Germar  have 
recorded  two  instances  of  it  among  the  Cole- 
optera,  the  former  in  the  Lucanus  cervus,  and 
the  latter  in  the  Melolontha  vulgaris ;  and  Mr. 
Westwood  mentions  a  third  case  in  the  large 
water-beetle  ( Dyticus  marginalis ),  as  con- 
tained in  Mr.  Hope's  collection,  and  has  seen 
a  fourth  in  the  stag-beetle  (Lucanus  cervus ). 

Out  of  twenty-nine  recorded  cases  of  lateral 
hermaphroditism  in  Insects,  in  which  the 
sexual  characters  of  each  side  are  distinctly 
specified,  we  find  that  in  seventeen  instances 
the  right  side  was  male,  and  in  twelve  female. 
Burmeister  alleges  that  in  by  far  the  majority 
of  cases  the  right  side  is  male,  and  the  left 
female, —  a  statement  in  which  Meckel  co- 
incides, while  Westwood  maintains  the  reverse. 
The  cases  we  have  ourselves  collected  are  cer- 
tainly numerically  in  favour  of  the  former 

*  Economy  of  Nature  in  Glandular  Diseases, 
t  Kob's  Dissert,  rle  Mutatione  Sexus,  p.  19. 
VOL.  II. 


opinion,  but  the  data  are  as  yet  so  few,  and 
the  difference  so  trifling,  as  not  to  warrant  us 
to  come  to  any  decided  conclusion  on  this 
point. 

In  some  instances  we  find  among  insects  an 
imperfect  lateral  hermaphroditism  consisting  of 
some  parts  of  one  side,  as  of  one  or  more  of  the 
wings,  palpi,  or  antennse  being  formed  according 
to  a  different  sexual  type  from  the  same  parts 
of  the  opposite  side,  and  from  the  general  body 
of  the  animal.  Thus  in  the  Melitoea  described 
and  dissected  by  Klug  (see  Lateral  Herma- 
phroditism )  the  general  form  of  the  insect  was 
male,  but  the  left  eye,  palpus,  antenna,  and  left 
sexual  fang  were  smaller  than  in  individuals 
belonging  to  this  sex ;  the  left  antenna  was 
annulated  with  white  and  yellow  at  the  apex, 
while  the  right  was  of  one  colour;  the  general 
form  of  the  abdomen  was  male  but  somewhat 
thick,  and  the  wings  were  all  equal  and  male. 

In  a  Pontia  duplidice  mentioned  by  Rudol- 
phi, and  which  in  its  general  external  characters 
was  female,  the  right  anterior  wing  was  formed 
after  the  male  type,  and  the  sexual  organs  also 
resembled  those  of  the  male. 

Ochsenheimer  mentions  one  Gastrophaga 
qucrcus  with  the  body,  and  the  antenna?  and 
wings  on  the  left  side  female,  and  the  right  wings 
male ;  and  a  second  with  the  body  and  the 
right  side  female,  and  the  left  side  and  two  an- 
tennae male,  the  latter  being  brown  and  pecti- 
nated. 

In  this  imperfect  variety  of  lateral  herma- 
phroditism, the  malformed  wing,  antenna,  or 
palpus  is  sometimes  formed  after  one  sexual 
type  and  coloured  after  another.  In  a  male 
Melitwa  pha-be  noticed  by  Germar,  the  right 
wings  and  antenna  were  female  in  regard  to  size, 
but  male  in  respect  to  colouring  and  markings. 
In  a  female  Deilephila  galii,  he  found  the  left 
antenna  and  palpus  of  the  small  size  of  the  male, 
but  agreeing  in  colouring  and  markings  with  the 
corresponding  female  parts  on  the  right  side. 
In  a  Pontia  cardamincs,  which  was  male  in 
all  its  other  characters,  Ochsenheimer  observed 
the  right  superior  wing  marked  as  in  the 
female,  and  he  mentions  another  individual  of 
the  same  species  which  had  a  female  form  with 
some  male  colours. 

In  another  variety  of  insect  hermaphroditism 
the  sexual  difference  is  sometimes,  as  we  have 
already  noticed  in  regard  to  the  human  subject, 
expressed  not  by  a  lateral,  but  by  a  longitudinal 
sexual  antagonism,  or,  in  other  words,  the 
anterior  and  posterior  parts  of  the  body  are 
formed  after  the  two  opposite  sexual  types. 
Thus  in  a  Satwnia  carpini  described  by 
Ochsenheimer,  the  antennae  were  male,  the 
superior  wings  male  in  form,  but  coloured  as 
in  the  female,  and  the  posterior  wings,  with  the 
exception  of  a  reddish  brown  spot  upon  the  left, 
were,  with  the  body  and  other  parts,  female. 

Lastly,  in  a  third  variety  of  external  hermaphro- 
ditic conformation  in  Insects,  we  find  the  char- 
acters of  the  two  sexes  mixed  up  and  crossed  in 
different  irregular  combinations  upon  the  body 
of  the  same  individual.  In  a  Gastrophaga 
castrensis  described  by  Rudolphi,  and  where 
the  male  type  predominated,  with  a  tendency, 

3  8 


722 


HERMAPHRODITISM. 


however,  in  all  parts  to  the  female  form,  the 
right  antenna  and  the  wings  on  the  opposite  or 
left  side  were  distinctly  female,  while  the  left 
antenna  and  right  wings  were  entirely  male, 
the  latter  being  only  somewhat  larger  than  in 
male  insects,  and  the  colours  brighter  than  in 
the  female.  In  a  Bombyx  castremis  alluded 
to  by  Westwood,  the  wings  on  the  right  side, 
and  the  antennre  and  abdomen  of  the  left,  were 
those  of  a  male,  while  the  left  winsr,  right  an- 
tenna;, and  right  side  of  the  abdomen  were 
those  of  a  female. 

GENERAL  SUMMARY  WITH  REGARD  TO  THE 
NATURE  OF  HERMAPHRODITIC  MALFORMA- 
TIONS. 

1 .  Of  the  varieties  of  spurious  hermaphro- 
ditism.— On  some  of  these  varieties  it  is  un- 
necessary for  us  to  dwell  here.  The  first 
species  of  spurious  male  hermaphroditism,  or 
that  arising  from  extroversion  of  the  urinary 
bladder,  is  elaborately  discussed  elsewhere 
(see  Bladder);  and  two  others,  namely,  the 
second  female  species  consisting  of  prolapsus 
of  the  uterus,  and  the  second  male  consisting  of 
an  adhesion  of  the  penis  to  the  scrotum,  seem 
both  referable  to  the  head  rather  of  disease  than 
of  original  malformation.  This  latter  indeed  ap- 
pears in  all  probability  only  an  effect  or  result  of 
adhesive  inflammatory  action  in  the  affected  parts 
during  embryonic  or  foetal  life.  Both  of  the  two 
remaining  forms  of  spurious  hermaphroditism, — 
viz.  those  consisting  of  hypospadic  fissure  of  the 
urethra,  scrotum,  and  peiinaeum  in  the  male, 
and  of  abnormal  magnitude  of  the  clitoris  in  the 
female, — seem  readily  explicable  upon  the  doc- 
trine of  arrestment  and  anormality  in  the  deve- 
lopment of  the  malformed  parts. 

We  have  already  described  at  sufficient 
length  the  process  of  development  of  the  dif- 
ferent copulative  organs,  and  have  shewn  that 
those  various  degrees  of  hypospadic  malforma- 
tion which  constitute  the  common  form  of 
spurious  hermaphroditism  in  the  male,  may  be 
traced  to  arrestment  of  this  process  at  various 
periods  or  stages  of  its  progress.  And  we  may 
here  remark  that  the  earlier  this  arrestment 
occurs,  the  distinction  of  the  true  sexual  type  of 
the  malformed  organs  will  always  be  the  less 
marked,  because  the  younger  the  embryo,  and, 
on  a  similar  principle,  the  lower  we  descend  in 
the  scale  of  animal  existence,  we  find  the  dif- 
ferences between  the  organs  of  the  two  sexes 
proportionally  the  less  pronounced,  until  at 
last  we  arrive  at  that  primitive  type  in  which 
these  organs  present  altogether  a  common,  neu- 
tral,'or  indeterminate  character. 

We  have  also  already  shewn  that  at  a  certain 
early  stage  of  the  development  of  the  female 
organs,  the  female  clitoris  holds  the  same,  or 
nearly  the  same  relatively  larger  size  to  the 
whole  embryo  as  the  penis  of  the  male,  and 
that  so  far  we  may  consider  the  occasional 
occurrence  of  spurious  hermaphroditism  from 
magnitude  of  the  clitoris,  and  its  resemblance 
in  this  respect  to  the  male  organ,  as  a  perma- 
nent condition  of  a  type  of  embryonic  structure 
that  is  normally  of  a  temporary  or  transitory 
existence  only.    But  besides  this  permanence 


of  the  embryonic  type  of  the  clitoris,  we  must 
farther,  in  all  the  more  complete  instances  of 
spurious  female  hermaphroditism,  admit  an 
excess  of  development  in  the  malformed 
external  sexual  parts,  and  more  particularly  in 
the  line  of  the  median  reunion  of  the  two 
primitive  lateral  halves  or  divisions  of  these 
parts.  In  this  way  the  vagina  (a  remnant  in  the 
female  of  the  primitive  perineal  cleft  or 
fissure)  is  often  in  such  cases  more  or  less  con- 
tracted and  closed,  so  much  so  indeed  in  some 
instances  as  to  leave  only,  as  in  the  male,  a 
small  canal  common  to  the  genital  and  urinary 
passages.  If  the  median  junction  is  extended 
still  farther,  this  canal  comes  also  to  imitate  the 
male  urethra  in  this  respect,  that  it  is  united  or 
shut  up  below  in  such  a  way  as  to  be  carried 
onward  to  a  greater  or  less  length,  and  in  a 
more  or  less  perfect  condition  along  the  under 
surface  of  the  enlarged  clitoris  ;  and  occasion- 
ally the  male  type  of  structure  is  still  more 
completely  repeated  in  the  female  organization 
by  the  median  reunion  of  the  two  labia,  giving 
the  appearance  of  theunited  scrotum  and  closed 
perinaum  of  the  opposite  sex. 

If  we  divide  the  whole  sexual  apparatus  of 
the  male  and  female  into  three  corresponding 
transverse  spheres  or  segments, — the  first  or 
deep  parts  including  the  testicles  and  ovaries, 
the  second  or  median  comprehending  the  male 
seminal  canals  and  prostate  gland,  and  the 
female  oviducts  and  uterus,  and  the  third  or 
external  embracing  the  copulating  organs  of  the 
two  sexes, — we  shall  find  that,  relatively 
speaking,  the  deep  and  the  external  spheres  are 
naturally  most  developed  in  the  male  economy, 
while  the  median,  comprising  the  uterus,  (the 
principal  and  most  active  organ  in  the  female 
reproductive  system,)  is  developed  in  the 
greatest  degree  in  that  sex.  In  malformed 
females  presenting  a  spurious  hermaphroditic 
character,  this  important  portion  of  the  female 
sexual  organization  is,  in  general,  either  itself 
in  some  respects  malformed,  or,  from  the 
structure  of  the  other  parts  of  the  sexual  appa- 
ratus being  imperfect,  its  specific  importance  in 
the  economy  is  cancelled,  and  therefore  the 
energy  of  development  takes  the  same  direction 
as  in  the  male,  being  expended  upon  the  more 
complete  evolution  of  the  organs  of  the  external 
and  deep  spheres.  Hence  the  greater  size  of 
the  clitoris,  and  the  greater  development  which 
we  have  just  now  pointed  out,  in  the  median 
line  of  reunion  of  the  external  sexual  parts ; 
and  hence  also  the  occasional  though  rare 
occurrence,  in  the  same  cases,  of  the  descent  of 
the  ovaries  through  the  inguinal  rings  into  the 
labia, — an  anomaly  that  certainly  consists  in 
a  true  excess  of  development,  and  which  we 
cannot  but  regard  as  interesting,  both  in  this 
respect,  and  as  affording  a  new  point  of 
analogy  between  these  organs  themselves  and 
the  male  testicles. 

There  is  another  and  equally  interesting  point 
of  vie\v  in  which  we  may  look  upon  this  sub- 
ject. Not  only  are  the  forms  of  spurious  her- 
maphroditism which  we  have  been  considering, 
capable  of  being  traced  backward  to  certain  tran- 
sitory types  of  sexual  structure  in  the  embryos 


HERMAPHRODITISM. 


723 


of  those  animal  species  in  which  the  malfor- 
mations in  question  occur,  but  they  may  be  shewn 
also  to  present  in  their  abnormal  states  repe- 
titions of  some  of  the  normal  and  permanent 
conditions  of  the  sexual  organs  in  various  species 
of  animal  beings  placed  lower  in  the  scale  of 
life.  Thus  the  occasionally  imperforate  penis 
of  the  male  hermaphrodite  lias  been  supposed 
to  have  an  analogue  in  the  naturally  solid  penis 
of  some  of  the  species  of  the  genera  Doridium 
and  Hyalcea*  Its  more  or  less  grooved  or  hy- 
pospadie  condition  is  similar  to  the  natural 
type  of  the  same  part  in  some  hermaphrodite 
Mollusca,  as  in  the  Planorbis  and  Murex  :f 
in  its  occasional  diminutive  size  it  approaches 
the  general  smallness  of  the  partially  fissured 
penis  of  most  birds  and  reptiles  ;  and  we  find 
it  in  the  Rodentia  and  Marsupiata  tied  down 
by  a  short  prepuce  in  a  way  analogous  to  what 
is  seen  in  some  cases  of  severe  hypospadias. 
In  the  sloth  (  Uradypus  tridactylus)  the  penis 
is  small  and  grooved  in  its  lower  surface,  and 
has  the  urethra  opening  at  its  base  ;J  and  in 
several  of  the  male  Rodentia  the  scrotum  is 
also  cleft,  and  has  its  two  opposed  surfaces 
smooth,  humid,  and  free  of  hair,  as  in  most 
cases  of  hypospadic  hermaphroditism  in  man. 
In  Ophidian  and  in  most  Saurian  Reptiles,  the 
male  seminal  ducts  open  at  once  externally,  as 
in  some  male  hermaphrodites,  at  the  root  of  the 
fissured  penis. 

The  fact  of  the  testicle  some  time  remaining, 
in  cases  of  hermaphrodite  formation  in  the 
human  subject,  within  the  cavity  of  the  ab- 
domen, presents  to  us  in  a  permanent  state 
their  original  but  changeable  position  in  the 
early  foetus,  and  at  the  same  time  affords  a 
repetition  of  their  normal  situation,  in  almost 
all  the  lower  tribes  of  animals,  and  in  the 
Cetacea,  Amphibia,  Edentata,  and  some  Pa- 
chydermata,  as  the  Cape  Marmot  (Hyrux ) 
and  Elephant,  among  the  Mammalia. 

The  malformed  clitoris  in  instances  of 
spurious  hermaphroditism  assumes  also,  in  its 
abnormal  state,  types  of  structure  that  we  find 
as  the  normal  condition  of  the  organ  in  various 
inferior  animals.  Thus  in  female  Cetacea  and 
Rodentia,  and  in  the  animals  included  in 
Cuvier's  order  of  Carnassiers,  but  more  par- 
ticularly among  the  Quadrumana,  the  clitoris 
retains  as  its  permanent  normal  type  that 
relatively  larger  size  which  we  observe  in  the 
early  foetus,  and  in  female  hermaphrodites  in 
the  human  subject  :  and  further,  as  is  some- 
times seen  in  such  malformed  individuals,  the 
clitoris  becomes  partially  traversed  by  the 
urethra,  as  in  the  Ostrich,  Emu,§  and  Ant- 
eater  ;||  and  in  the  Loris  (as  we  have  noticed  in 
a  preceding  page)  and  Maki,  it  is  completely 
enclosed,  like  that  of  the  male,  in  the  body  of 

*  Burdach's  Physiologie,  Bd.  i.  §  132,  p.  231. 

t  Tiedemann's  Zeitschrift  fuer  Physiologie,  Bd, 
i.  s.  15,  or  Cuvier,  Anat.  Comp.  torn.  v.  p.  182. 

\  Meckel,  Beitrasge  zur  vergleiclicnden  Anatomic, 
Bd.  ii.  cap.  i.  p.  125. 

j  Cuvier,  Anat.  Comp.  t.  v.  p.  129. 

||  Meckel,  Archiv.  fuer  die  Physiologie,  Bd.  v. 
».  66. 


the  organ,  forming  a  continuous  and  perfect 
canal  through  it. 

We  may  here  further  observe,  (though  the 
illustrations  should  more  properly  belong  to  the 
next  section,)  that  in  cases  of  true  hermaphro- 
ditism also  in  man  and  quadrupeds,  as  well  as 
in  the  above  spurious  varieties,  there  may  be 
often  traced  in  some  portions  of  the  abnormal 
structures  a  sexual  type  bearing  a  greater  or 
less  analogy  to  the  corresponding  parts  of 
those  inferior  animals  that  are  naturally  andro- 
gynous. Thus,  in  instances  of  true  hermaphro- 
ditism, the  orifices  of  the  sexual  ducts  or 
passages  occasionally  open  into  a  common 
cavity,  as  is  normally  the  case  in  some  species' 
of  Doridium,  Helix,  and  other  Mollusca  ;  or  the 
female  oviducts  or  Fallopian  tubes,  and  the 
male  vasa  deferentia,  run  closely  alongside  of 
each  other  without  any  communication  between 
their  canals,  as  in  the  Alj/psia  and  most  Gas- 
teropoda. Indeed  the  occasional  co-existence 
even  of  both  testicles  and  ovaries  in  individuals 
among  the  higher  animals  would  be  only  a 
repetition  of,  or  retrogression  to,  the  normal 
sexual  type  of  those  genera  of  animals  that  we 
have  just  named,  and  of  the  Planaria,  Ces- 
toidea,  and  other  natural  hermaphrodites. 

In  this  way  we  see,  that,  (as  in  many  other 
monstrosities,)  the  several  varieties  of  malfor- 
mation in  the  sexual  organs  occurring  in 
spurious  human  hermaphroditism  do  not  con- 
sist of  the  substitution  of  an  entirely  new  and 
anomalous  type  of  structure,  but  are  only 
repetitions  of  certain  types  of  the  same  organs 
that  are  to  be  met  with  both  in  the  human 
foetus  and  in  the  inferior  orders  of  animal 
beings.  The  investigation  of  the  whole  subject 
shews  us  in  reference  to  the  sexual  organs, 
what  is  equally  true  in  regard  to  all  the  other 
organs  of  the  body, — that  their  different  stages 
of  development  in  the  embryos  of  man 
and  of  the  higher  orders  of  animals  cor- 
respond to  different  stages  of  their  deve- 
lopment in  the  series  of  animal  beings 
taken  as  a  whole  ;  so  that  here,  as  elsewhere, 
the  facts  of  Comparative  Anatomy  are  repro- 
duced in  those  of  Embryology,  and  both  are 
repeated  to  us  by  nature  on  a  magnified  scale 
in  the  anatomy  of  the  malformations  of  the 
part, —  a  circumstance  amply  testifying  to  the 
intimate  relations  which  subsist  between  Com- 
parative Anatomy,  the  anatomy  of  Embryonic 
Development,  and  that  of  Monstrosities. 
Indeed  proportionally  as  our  knowledge  of 
malformations  has  increased,  it  has  shewn  us 
only  the  more  strongly  that  the  laws  of  forma- 
tion and  malformation, — of  normal  and  abnor- 
mal development,  are  the  same,  or  at  least  that 
they  differ  much  more  in  degree  than  in  essence, 
and  that  the  study  of  each  is  calculated  recipro- 
cally to  illustrate  and  to  be  illustrated  by  the 
study  of  the  other. 

2.  Nature  of  true  hermaphroditic  malfor- 
mations.— Of  the  nature  of  local  malforma- 
tions by  duplicity,  we  at  present  possess  much 
less  precise  knowledge  than  of  those  of  simple 
defect  or  simple  excess  of  development ;  but 
there  are  certain  facts  ascertained  with  regard 

3  »  2 


724 


HERMAPHRODITISM. 


to  the  formation  of  the  sexual  organs,  which 
may  enable  us  to  make  an  approach  at  least  to 
accurate  ideas  of  the  character  and  origin  of 
those  anormalities  that  constitute  the  several 
varieties  of  true  hermaphroditism.  These  facts 
relate  to  the  interesting  subject  of  the  unity  of 
structure  which  is  manifested  in  the  correspond- 
ing male  and  female  reproductive  organs  of  the 
human  subject,  and  of  other  species  of  bisexual 
animals. 

By  several  of  the  Greek,  Roman,  and  Ara- 
bian physiologists,*  the  respective  organiza- 
tions of  the  two  sexes  were  considered  as  in 
some  degree  typical  of  one  another,  the  female 
being  regarded  as  an  inverted  male,  with  the 
testicles  and  penis  turned  inwards  to  form  the 
ovaries  and  uterus.  This  doctrine  of  analogy 
between  the  male  and  female  sexual  organs 
has,  with  various  modifications,  been  very  ge- 
nerally admitted  by  modern  physiologists,  and 
in  some  of  its  bearings  it  has  been  made,  more 
particularly  of  late  years,  the  subject  of  consi- 
derable discussion.  The  testicles  are  still  re- 
garded as  organs  which  correspond  with  the 
ovaries  in  their  original  situation,  in  their  vas- 
cular and  nervous  connections,  and  in  their  re- 
lative sexual  functions.  The  recent  progress 
of  the  anatomy  of  the  development  of  the  em- 
bryo has  also  shewn  that  the  two  organs  cor- 
respond in  their  primitive  origin.  It  is  now 
well  ascertained  that  the  large  masses  occupy- 
ing each  side  of  the  abdomen  of  the  embryo 
at  an  early  stage  of  development,  and  which 
Rathke  has  named  the  Wolffian  bodies  after 
their  illustrious  discoverer,  form,  in  Birds  and 
Mammalia  at  least,  the  primordial  matrices 
upon  which  the  urinary  and  genital  organs  are 
developed.  On  the  inner  side  of  each  of  these 
matrices  a  small  body  is  early  developed,  which 
seems  to  become  afterwards  either  a  testicle  or 
an  ovary,  according  to  the  particular  ulterior 
sexual  type  which  the  embryo  assumes. 

In  further  following  up  the  analogy  of  struc- 
ture between  the  organs  of  the  two  sexes,  the 
vasa  deferentia  of  the  male  are  generally  com- 
pared to  the  Fallopian  tubes  of  the  female, 
the  scrotum  to  the  external  labia,  the  body  of 
the  penis  to  the  clitoris,  and  its  corpus  spon- 
giosum, or,  according  to  others,  its  prepuce,  is 
regarded  as  corresponding  in  type  with 
the  female  nymphje.  A  considerable  dif- 
ference of  opinion,  however,  still  prevails 
as  to  the  prototype  of  the  female  uterus  in  the 
male  system.  Some  anatomists,  as  Burdach, 
Steghlener,  and  Blainville,  regard  the  uterus 
and  male  vesiculae  seminales  as  corresponding 
parts ;  while  others,  as  Meckel,  Cams,  Schmidt, 
Ackermann,  and  Serres,  compare  the  uterus  to 
the  male  prostate.  A  sufficient  number  of 
facts  seems  still  wanting  to  determine  the  accu- 
racy and  justness  of  either  of  these  analogies. 
There  are  instances  of  malformation  on  record 
which  appear  to  favour  both  opinions,  and  there 
are  other  cases  which  almost  incline  us  to  be- 

*  Aristotle,  Hist.  An.  lib.  i.  17.  Galen,  De  Semine, 
lib.  ii.  &  De  Usu  Partium,  c.  i.  Rhases,  De  Re 
Medica,  lih.  i.  cap.  26.  Avicenna,  De  Membris  Ge- 
nerut.  lib.  i:i.  21,  &c. 


lieve  that  the  vesicula?  seminales  correspond  to 
the  fundus  or  body  of  the  uterus  in  the  human 
subject,  and  to  the  cornua  uteri  in  quadrupeds  ; 
while  the  prostate  represents  in  the  male  struc- 
ture the  lower  portion  or  cervix  of  the  same 
organ.  The  phenomena  of  the  development 
of  the  reproductive  organs  in  the  embryo  will, 
when  more  fully  investigated,  probably  serve  to 
clear  up  this  question. 

M.  Geoffiroy  St.  Hilaire  has  propounded 
views  of  the  analogy  of  the  male  and  female 
organs  in  some  respects  different  from  the  above. 
He  divides  the  uterus  of  the  human  subject 
into  the  body  and  the  upper  part  or  fundus,  the 
latter  corresponding  to  what  constitutes  the 
cornua  uteri  in  the  human  embryo,  and  in  adult 
quadrupeds.  Further,  believing  that  in  the 
determination  of  all  analogies  in  type  and 
structure  between  different  organs,  the  origin 
and  course  of  the  bloodvessels  supplying  the 
part  ought  to  be  our  principal  criterion,  he  has 
been  led,  by  the  study  of  the  distribution  of  the 
branches  of  the  hypogastric  arteries,  to  consider 
the  body  of  the  uterus  and  the  vesicula?  semi- 
nales as  repetitions  of  each  other  in  the  two 
sexes  ;  and,  contraiy  to  the  opinion  of  most 
anatomists,  he  conceives  that  the  male  vasa 
deferentia  strictly  correspond  with  the  fundus 
or  cornua  uteri,  and  that  the  epididymis  repre- 
sents a  coiled-up  Fallopian  tube,  or  in  other 
words  that  the  Fallopian  tube  is  an  unrolled 
epididymis.  M  St.  Hilaire  has  offered  the 
following  table  to  shew  what  he  conceives  to 
be  analogous  organs  in  the  two  sexes : — * 


In  the  male. 
Testicle  = 
Epididymis  — 
Vas  deferens.  = 
Vesicula  seminalis  = 
Sheath  of  the  penis  = 
Penis  = 


In  the  female. 
Ovary 

Fallopian  tube 
Cornu  of  the  uterus 
Body  of  the  uterus. 
Vagina 
Clitoris 


In  tracing  out  the  analogies  between  the 
male  and  female  parts,  the  mode  in  which  we 
ought  to  consider  the  female  vagina  has  given 
rise  to  some  diversity  of  opinion.  From  the 
above  table  it  appears  that  M.  St.  Hilaire  con- 
siders it  to  be  represented  in  the  male  organiza- 
tion by  the  sheath  of  the  penis,  but  we  are  cer- 
tainly inclined  to  view  it  in  a  different  light, 
and  to  regard  it  as  a  part  in  so  far  peculiar  to 
the  female,  that  it  consists  of  a  permanent 
condition  of  that  urino-genital  perineal  fissure 
that  we  have  already  described  as  existing  at  a 
certain  period  in  the  embryos  of  both  sexes, 
and  which  is  latterly  shut  up  in  the  male,  or, 
speaking  more  accurately,  it  is  contracted  into 
what  forms  the  pelvic  portion  of  the  male 
urethra. 

If  this  were  a  fit  opportunity  for  following 
out  the  consideration  of  the  unity  of  type  be- 
tween the  male  and  female  reproductive  organs, 
it  would  be  easy  to  shew  the  justness  of  those 
greater  analogies  that  we  have  mentioned,  by 
pointing  out  other  numerous  minor,  but  still 
strong  points  of  correspondence  manifested  in 

*  Phil.  Anat.  torn.  i.  (1822,)  p.  471. 


HERMAPHRODITISM. 


72* 


the  abnormal  conditions  and  localities  of  the 
ovaries  and  testicles  in  ihe  higher  animals,  and 
in  their  conformity  of  structure  in  some  of  the 
lower.  Thus  among  Insects,  in  the  genus  Li- 
bellula  the  long  cylindrical  testes  of  the  males 
correspond  with  the  long-shaped  ovaries  of  the 
females ;  in  the  Locusta  and  Gryllotalpa, 
there  are  ramose  bunched  testicles  with  analo- 
gous fasciculated  ovaries  ;  in  the  Lumellicornia 
we  find  compound  radiating  and  united  testes, 
with  similar  radiating  and  united  ovaries  ;  and 
sometimes,  as  in  the  genera  Melolontfia  and 
Tric/uus,lhe  number  of  the  single  bodies  in  the 
testicles  corresponds  with  the  number  of  the 
oviducts.* 

We  have  already,  when  considering  spurious 
hermaphroditism  in  the  female,  mentioned 
several  facts  illustrative  of  the  analogical  pe- 
culiarities in  structure  between  the  male  penis 
and  female  clitoris  in  some  species  of  animals  ; 
and  Burmeister.f  who  regards  the  ovipositors 
and  stings  of  female  insects  as  corresponding 
to  the  clitoris  in  the  female  Vertebrata,  has 
pointed  out  a  remarkable  conformity  of  struc- 
tural type  between  its  valves  and  those  of  the 
penis  of  the  male  of  the  same  species. 

Some  organs  that  are,  as  far  as  regards  their 
functions,  peculiar  and  essential  to  one  sex 
only,  are  nevertheless  found  to  be  repeated  in 
the  opposite  sex  in  the  form  of  an  analogous 
rudimentary  type  of  structure.  Thus,  in  the 
male  we  may  observe  the  unity  of  sexual  struc- 
ture maintained  in  the  presence  of  the  rudi- 
ments of  the  mammary  gland,  which  is  func- 
tionally an  organ  of  the  female  system  only.  In 
the  human  subject,  and  in  animals  whose  females 
have  pectoral  mamma:,  these  organs  occupy  the 
same  position  in  the  male;  while  in  those 
species  of  quadrupeds  in  which  they  are  placed 
in  the  inguinal  region,  we  find  them  in  the 
corresponding  males  forming  the  scrotum  or 
bags  for  containing  the  testicles.  Hence,  as  we 
have  already  seen,  the  testicles,  in  cases  of  mal- 
formation in  these  animals,  are  often  laid  upon 
or  imbedded  in  the  udder.  In  the  same  way 
in  the  Marsupiata,  the  bone  which  the  female 
has  for  supporting  the  marsupium  is  repeated 
in  the  organization  of  the  male,  although  in  the 
latter  we  cannot  conceive  it  to  serve  any  possible 
use.J: 

In  the  female  also  we  observe  in  some  points 
a  similar  disposition  to  the  rudimentary  repe- 
tition of  parts  that  are  essential  or  peculiar 
only  to  the  male  organization,  as  in  the  repeti- 
tion in  the  clitoris  of  some  female  Rodentia,  of 
the  penis-bone  of  the  male,  and  in  the  forma- 
tion of  rudimentary  forms  of  those  processes 
of  peritoneum  which  constitute  the  tunicse 
vaginales.  We  are  ourselves  inclined  also  to 
regard  the  common  crescentic  form  of  the  hy- 
men of  the  human  female  in  the  same  light,§ 

*  Burmeister's  Entomology,  §  154.  p.  222. 
t  Loc.  cit. 

%  Home's  Lect.  on  Comp.  Anat.  vol.  ii.  pi.  v. 

§  Burdach  ( Phys.  §137,)  considers  the  small 
cutaneous  fold  situated  at  the  orifices  of  the  vasa 
deferentia,  and  Stiebel  the  membrane  placed  at  the 
extremity  of  the  urethra  (Meckel's  Archiv.  fur 
Physiol.  J5d.  viii.  s.  207.)  as  the  analogue  in  the 
male  for  the  female  hymen. 


and  to  consider  it  merely  as  an  abortive  attempt 
at  that  closure  of  the  perinseal  fissure  which 
we  have  already  described  as  effected  at  an 
early  period  in  the  male  embryo — an  opinion 
in  which  we  conceive  we  are  borne  out  both  by 
the  history  of  the' development  and  the  study 
of  the  malformations  of  the  external  sexual 
parts  in  the  female. 

M.  Isidore  St.  Hilaire  read,  in  1833,  to  the 
French  Academy  a  memoir,*  in  which,  follow- 
ing up  the  doctrine  of  his  father  with  regard  to 
the  determination  and  distinction  of  the  type  of 
parts  by  the  particular  vessels  distributed  to 
thern,  he  endeavoured  to  shew  some  new 
points  of  analogy  between  the  male  and  female 
organs,  and  to  develop  new  views  with  regard 
to  the  origin  and  particular  varieties  of  herma- 
phroditic malformations.  With  Burdach,  he 
divides  the  whole  reproductive  apparatus  of 
either  sex  into  three  transverse  spheres  and 
into  six  portions  or  segments  in  all,  or  three  on 
each  side,  viz.,  1  and  2,  the  deep  organs,  in- 
cluding the  male  testicles  and  female  ovaries  ; 

2  and  3,  the  middle  organs,  or  male  prostate 
and  vesiculae  seminales,  and  female  uterus ; 

3  and  4,  the  external  organs,  comprehending 
the  penis  and  scrotum  of  the  male,  and  the 
clitoris  and  vulva  of  the  female.  Each  of  these 
portions  or  segments  is,  M.  St.  Hilaire  points 
out,  supplied  by  an  arterial  trunk  peculiar  to 
itself,  and  the  corresponding  organs  of  the  male 
and  female  by  corresponding  arterial  branches, 
as  the  deep  organs  of  both  sexes  by  the  two 
spermatics,  the  middle  by  branches  of  the  two 
hypogastrics,  and  the  external  by  some  other 
hypogastric  branches,  and  by  the  external  pu- 
dics.  This  circumstance,  he  conceives,  renders 
all  the  segments  in  a  certain  degree  independ- 
ent of  the  others,  both  as  regards  their  develop- 
ment and  existence,  and  allows  of  the  occa- 
sional evolution  of  any  one  or  more  of  them 
on  a  type  of  sexual  structure,  different  from 
that  upon  which  the  others  are  formed  in  the 
same  individual. 

Though  assuredly  we  cannot  subscribe  to 
the  speculations  of  the  elder  St.  Hilaire,  that 
the  development  in  the  embryo  of  male  testi- 
cles or  female  ovaries,  and  consequently  the 
whole  determination  of  the  sex,  is  originally  re- 
gulated by  the  mere  relative  angle  at  which  the 
first  two  branches  of  the  spermatic  arteries 
come  off",  and  the  kind  of  course  which  they 
follow,!  (more  particularly  as  it  is  admitted  by 
most  physiologists  that  the  bloodvessels  grow, 
not  from  their  larger  trunks  or  branches  towards 
their  smaller,  but  from  their  capillary  extremi- 
ties towards  their  larger  branches,)  yet  we 
believe  that  the  doctrine  of  the  comparative 
independence  of  the  different  segments  of  the 

*  Arch.  Gen.  de  Med.  (1833)  torn.  i.  p.  306. 

t  Anat.  Phil.  torn.  i.  p.  359.  .  .  "  L'ordre 
de  variations  des  sexes  tient  a  la  position  d'un 
artere.  .  .  Le  plus  on  le  moins  d'ecarlement 
des  deux  branches  spermatiques  motive  effective- 
ment  cette  preference.  Qtieles  deux  branches  de 
l'artere  spermatique  descendent  parallolement  et  de 
compagnie,  cette  circonstance,  je  le  repete,  cette 
circonstance  donne  le  sexe  male  ;  qu'clles  s'ecar- 
tcnt  a  leur  point  de  partage,  nous  avons  le  sexe  fc- 
mcllc." 


726 


HERMAPHRODITISM. 


reproductive  organs  pointed  out  by  the  son  is 
in  its  general  principles  correct.  At  the  same 
time  we  would  here  remark  that  we  conceive 
the  doctrine  would  have  been  founded  more  on 
truth  if  the  influence  of  the  nervous  branches 
supplying  the  different  reproductive  organs  had 
been  taken  into  account  along  with  that  of 
their  arterial  vessels,  because,  as  we  shall 
point  out  when  speaking  of  the  causes  of  her- 
maphroditism, there  appears  to  be  some  con- 
nection between  the  state  of  the  nervous  sys- 
tem and  the  degree  or  condition  of  sexual  de- 
velopment. 

The  consideration  of  the  preceding  ana- 
logies in  structure  between  the  male  and 
female  organs  is  interesting  in  itself,  and,  as  far 
as  relates  to  our  present  subject,  important  in 
this  respect,  that  it  enables  us  in  some  degree 
to  understand  how  it  happens  that,  without  any 
actual  monstrous  duplicity,  we  should  some- 
times find,  in  an  organization  essentially  male, 
one  or  more  of  the  genital  organs  absent  and 
replaced  by  an  imperfect  or  neutral  organ,  or 
by  the  corresponding  organ  of  the  opposite 
sex,  and  vice  versa  ;  inasmuch  as  it  shews  us 
that  the  moulds  in  which  the  analogous  organs 
of  the  two  sexes  are  formed  are  originally  the 
same.  Hence  there  is  no  difficulty  in  con- 
ceiving that,  in  the  body  of  the  same  individual, 
the  primitive  structural  elements  of  these  parts 
should  occasionally,  in  one  or  more  points  or 
segments,  take  on,  in  the  process  of  development, 
a  different  sexual  type  from  that  which  they 
assume  at  other  points.  Indeed  some  physi- 
ologists, as  we  shall  immediately  see,  deny 
that  the  most  complete  hermaphroditic  malfor- 
mations ever  consist  of  anything  except  such  a 
want  of  conformity  between  the  sexual  type  of 
different  portions  of  the  reproductive  appa- 
ratus. 

If  each  of  the  six  segments  (and  we  believe 
that  their  number  might  be  shewn  to  be  really 
greater  than  this,)  is  thus  an  independent  cen- 
tre of  development  in  the  formation  of  the 
sexual  apparatus,  and  is  consequently  liable 
also  in  abnormal  cases  to  have  its  own  parti- 
cular malformations,  and  to  assume,  either 
alone  or  along  with  some  of  the  other  seg- 
ments, a  sexual  type  different  from  the  re- 
mainder, it  is  evident  that  we  may  have  as 
many  varieties  of  true  hermaphroditism,  with- 
out any  real  duplicity,  as  it  is  possible  to  con- 
ceive differences  of  arrangements  among  these 
six  segments.  Again,  however,  one  or  more 
of  these  segments  may  preserve  from  a  deve- 
lopment its  original  indeterminate  or  neutral 
sexual  type,  while  the  others  are  variously 
formed  either  upon  one  or  upon  both  sexual 
types ;  or  one  or  more  of  the  segments  may, 
by  a  true  malformation  by  duplicity,  have 
evolved  within  them  the  corresponding  organs 
of  the  two  sexes ;  and  if  we  consider  the  dif- 
ferent arrangements  of  double  and  single 
sexual  parts  that  might  thus  occur  in  the  six 
separate  segments,  we  may  gain  some  idea  of 
the  great  diversities  of  structure  in  the  sexual 
parts  that  are  liable  to  be  met  with  in  instances 
of  true  hermaphroditism. 

The  above  forms,  as  it  appears  to  us,  the 


most  sound  and  rational  solution  of  the  nature 
and  origin  of  many  forms  of  true  hermaphro- 
ditism which  physiological  science  is  capable 
of  affording,  upon  our  present  limited  know- 
ledge of  the  laws  of  development ;  and  its 
application  to  the  explanation  of  the  different 
varieties  of  lateral,  transverse,  and  vertical  her- 
maphroditism is  so  obvious  as  only  to  be 
required  to  be  alluded  to.    It  offers  to  us, 
however,  no  insight  into  the  probable  origin  of 
those  varieties  of  double  hermaphroditism  in 
which  there  is  an  actual  co-existence  upon  one 
or  upon  both  sides  of  the  body,  or,  in  other 
words,  in  the  same  segment  of  the  sexual 
apparatus,  of  both  the  corresponding  male  and 
female  organs.    We  can  only  refer  all  such 
instances  to  the  laws  which  regulate  the  occa- 
sional production  of  local  duplicities  indiffe- 
rent other  organs  of  single  bodies,  and  at  the 
same  time  confess  our  present  ignorance  of 
what  these  laws  are.    We  know  that  various 
individual  muscles,  nerves,  &c.  are  not  unfre- 
quently  found  double,  and  that  in  the  internal 
organs  of  the  body  examples  of  duplicity  in 
individual  viscera  are   occasionally,  though 
rarely,  observed  in  the  heart,  tongue,  trachea, 
oesophagus,    intestinal  canal,  &c.      In  the 
several   organs  composing    the  reproductive 
apparatus,  instances  of  similar  duplicity  would 
seem  to  be  even  more  common  than  among 
any  other  of  the  viscera.    Examples  of  three 
mamma?  upon  the  same  person  are  mentioned 
by  Bartholin,*  Borelli,-f  Lanzoni,I  Drejer,§ 
Robert,||  Petrequin,1f  and  others;**  and  cases 
in  which  the  number  of  these  organs  was  in- 
creased to  four  have  been  recorded  by  Faber,+f 
GardeuXjJt  Cabroli,§§  Lamy,||||  Tiedemann,^ 
Champion,***  Sinclair,-^}  ft.  Lee,Jtt  and 
Moore. §§§    An  instance  in  which  jive  mam- 
ma even  existed  upon  the  same  woman  is  re- 
ported to  have  been  seen  by  Gorre.||||||  Valen- 
tin^l^fir  and  Gunther****  have  recorded  sup- 
posed cases  of  duplicity  in  the  male  penis ;  and 
Arnaudfttt  nas  related  an  example  of  an  ana- 
logous malformation   in  the  female  clitoris. 
WeberJJJJ  met  with  a  double  vesiculaseminalis 

*  Acta  Med.  Hafn.  torn.  iii.  obs.  93. 

t  Ohserv.  Kar.  cent.  i.  p.  55. 

t  Eph.  Nat.  Cm.  Dec.  ii.  Ann.  v.  obs.  55. 

§  Arch.  Gen.  de  Med.  torn.  xvii.  p.  88. 

[)  J  urn.  Gen.  de  Med.  torn.  c.  p.  57. 

1]  Gazette  Medicale  for  April,)  1837.  Three 
distinc  t  mammas  in  a  father,  and  in  his  three  sons 
aud  two  daughters. 

**  Diet,  des  Sc.  Med.  torn,  xxxiv.  p.  529. 

tt  Eph.  Nat.  Cur.  Dec.  i.  Ann.  ii.  p.  346. 

Journ.  de  Med.  de  Corvisart,  torn,  ix,  p.  378. 

4§  Obs.  Anat.  vii. 

(Ill  Pantoni  Anat.  p.  267. 

*l\  11  Zeitschrift  fur  Physiologie,  lid. v.  s.  110.  One 
case  with  three,  and  three  with  four  nipples.  In 
one  case  the  malformation  was  hereditary. 

**"  Diet,  des  Sc.  Medic,  t.  xxx.  p.  377.  See 
also  p.  378. 

ttt  Statistical  Account  of  Scotland,  xix.  p.  288. 
tti  London  Med. -Chirurg. Trans,  vol.  xxi.  p.  266. 
§§§  Lancet  for  February  24,  1838. 
Mill  Diet,  des  Sc.  Med.  torn,  xxxiv.  p.  529. 

Eph.  Nat.  Cur.  Dec.  iii.  Ann.  iii.  obs.  77. 
****  Cohen  vom  Stein,  Halle,  1774,  p.  107. 
fttt  Mem.  de  Chir.  torn.  i.  p.  374. 
llli  Salzburg  Mediciuische  Zeitung,  1811,  s.  188. 


HERMAPHRODITISM. 


727 


on  each  side  ;  and  Hunter*  alludes  to  the  occa- 
sional occurrence  of  an  imperfect  supernumerary 
vas  deferens.  In  1833  a  case  of  a  doable  human 
uterus,  furnished  with  four  Fallopian  tubes  and 
four  ovaries,  was  shewn  by  Professor  Moureau 
to  the  Academie  de  Medecine.f  BlasiusJ 
dissected  the  body  of  a  man  on  whom  he 
detected  the  co-existence  of  three  testicles ;  the 
additional  testicle  was  of  the  natural  form  and 
size,  and  was  furnished  with  a  spermatic  artery 
and  vein  that  joined  in  the  usual  manner  the 
aorta  and  vena  cava;  it  lay  in  the  right  side  of 
the  scrotum.  Arnaud  found,  on  dissection, 
three  testicles  in  a  dog;  the  third  was  placed 
in  the  abdomen,  and  of  the  natural  consistence, 
figure,  and  size ;  it  was  furnished  with  a  vas 
deferens.§  Other  instances  of  triple  and 
quadruple  testicles  of  a  more  doubtful  charac- 
ter, inasmuch  as  the  observations  made  during 
life  were  not  confirmed  by  dissection  after 
death,  are  related  by  Voigtel,||  Sibbern,1[ 
Brown,*"*  Rennes,ff  and  others.f];  ScharfT§§ 
even  gives  an  alleged  case  of  a  man  with  five 
testicles,  three  of  which  are  stated  to  have 
been  well  formed,  while  the  other  two  were 
much  smaller  than  natural.  And,  lastly, 
Loder||||  is  said  to  have  exhibited  to  the  Goettin- 
gen  Academy  drawings  taken  from  the  body  of 
a  male  infant,  on  whom  all  the  sexual  apparatus 
existed  double,  there  being  two  penes,  a  double 
scrotum,  and  urinary  bladder,  and,  as  it  was 
supposed,  four  testicles. 

In  all  the  preceding  instances  the  local 
duplicity  of  the  particular  reproductive  and 
other  organs  adverted  to  existed  independently 
of  any  duplicity  in  the  body  in  general,  or  in 
any  other  individual  parts  of  it.  And  if  we 
once  admit,  (what  the  preceding  instances  will 
scarcely  allow  us  to  deny,)  that  there  may 
occur  a  duplicity  of  some  of  the  male  sexual 
organs  in  a  male,  or  of  some  of  the  female 
sexual  organs  in  a  female,  it  is  certainly  easy 
to  go  one  step  farther,  and  admit  that  the 
double  organ  or  organs  may,  however  rarely, 
be  formed  in  other  instances  upon  an  opposite 
sexual  type.  Indeed  all  our  knowledge  of  the 
unity  of  structure  and  development  between 
the  various  analogous  male  and  female  repro- 
ductive organs,  as  well  as  the  fact  of  the  occa- 
sional replacement  of  an  organ  of  the  one  sex 
by  that  of  the  other  in  cases  in  which  the 
sexual  type  is  entirely  single  (as  seen  in 
instances  of  lateral  hermaphroditism),  would 
lead  us  a  priori  to  suppose  that,  if  a  local 
duplicity  in  any  of  the  sexual  oi  trans  was  liable 
to  occur,  this  duplicity  would  sometimes  shew 
itself  in  the  double  organs  assuming  opposite 

*  Bell's  Anatomy,  vol.  iii.  p.  428. 

t  Journ.  Hebdom.  torn.  x.  p.  160. 

i  Ubs.  Med.  pars  iv.  obs.  20. 

§  Mem.  de  Chirurg.  s.  i.  p.  131. 

(J  Handbuch  der  Path.  Anat.  Bd.  iii.  s.  393. 

If  Acta  Hafn.  torn.  i.  p.  320. 

**  New  York  Medical  Repository,  vol.  iv.  p.  801. 
ft  Arch.  Gen.  de  Med.  t.  xxiii.  p.  17. 
tt  See  Haller's  El.  Phys.  torn.  v.  p.  411,  12.— 
and  Arnaud's  Chem.  de  Chirurg.  t.  i.  p.  128,  &c. 
v4  Eph.  Nat.  Cur.  Dec.  iii.  Ami.  v.  vi.  obs.  89. 
||||  Gbttingen  Anz.  1802,  p.  466. 


sexual  characters,  and  thus  constituting  some 
of  those  varieties  of  double  or  vertical  her- 
maphroditism that  we  have  already  had  occa- 
sion to  describe. 

In  the  preceding  observations  we  have  pro- 
ceeded upon  the  opinion  commonly  received 
by  physiologists,  of  the  fundamental  unity  of 
sex  among  all  individuals  belonging  to  the 
higher  orders  of  animals;  or,  to  express  it 
otherwise,  we  have  assumed  that  each  individual 
is,  when  normally  formed,  originally  furnished 
with  elemental  parts  capable  of  forming  one 
set  of  sexual  organs  only.  We  do  not  here 
stop  to  inquire  whether  this  single  sexual  type 
is,  in  all  embryos,  originally  female,  as  main- 
tained by  Rosenmiiller,  Meckel,  Blainville, 
Grant,  and  others;  or,  of  a  neutral  or  inter- 
mediate character,  as  supposed  by  the  St. 
Hilaires,  Sevres,  Ackermann,  Home,  &c,  and 
as  we  are  certain'y  ourselves  inclined  to  believe 
it.*  On  this  subject,  however,  a  physiological 
doctrine  of  a  different  kind  has  been  brought 
forward  by  Dr.  Knox,  and  this  doctrine  is  so 
intimately  connected  with  the  question  of  the 
nature  and  origin  of  true  hermaphrodites,  that 
we  must  here  briefly  consider  it. 

Dr.  Knox,f  in  conformity  with  some  more 
general  views  which  he  entertains  on  tran- 
scendental anatomy,  is  inclined  to  regard  the 
type  of  the  genital  organs  in  man  and  the  higher 
animals,  as  in  the  embryo,  originally  hermaph- 
roditic, or  as  comprising  elementary  yet  dis- 
tinct parts,  out  of  which  both  sets  of  sexual 
organs  could  be  formed  ;  and  lie  believes  that, 
owing  to  particular  but  unknown  circum- 
stances, either  the  one  or  the  other  only  of 
these  sets  of  elements  comes  to  be  evolved  in 
the  normal  course  of  development.  In  those 
abnormal  cases,  again,  in  which,  as  in  instances 
of  double  hermaphroditism,  more  or  fewer  of 
both  sets  of  genital  organs  are  present  upon 
the  same  individual,  he  maintains  that  this  is 
not  to  be  considered  as  a  malformation  by 
duplicity,  but  is  only  a  permanent  condition  of 
the  original  double  sexual  type,  and  is  attri- 
butable to  the  simultaneous  development  to  a 

*  Meckel  (De  Duplicitate  Monsirosa,  p.  14), 
and  Andrnl  (Anat.  l  ath.  torn.  i.  p.  101)  assume 
it,  after  Haller,  as  a  fact,  that  a  much  larger  pio- 
portion  of  monsters  belong  to  the  female  than  to 
the  male  sex  ;  and  while  they  attribute  this  circum- 
stance to  the  genital  organs  in  these  beings  retain- 
ing, from  the  general  defect  of  development,  their 
original  female  sexual  character,  they  at  the  same 
time  consider  this  circumstance  to  be  strongly 
corroborative  of  this  particular  doctrine.  Isid. 
St.  Hilaire  has  shewn  (Hist,  des  Anomal.  t.  iii. 
p.  387)  that  the  supposed  fact  itself  does  not  hold 
true  in  respect  to  some  genera  of  monsters,  and  is 
even  reversed  in  others ;  and  he  doubts  if  it  be  of 
such  a  degree  of  generality  in  respect  to  mon- 
sters in  general  as  to  merit  to  be  raised  into  a 
teratological  law.  If  the  views  of  Meckel  were 
correct,  we  should  certainly  expect  at  least  that 
spurious  hermaphroditism,  where  the  development 
of  the  sexual  parts  is  commonly  abnormal  from 
defect,  should  be  much  more  frequent  in  the  female 
than  in  the  male.  The  list,  however,  of  recorded 
cases  of  it  in  the  latter  is,  we  believe,  more  than 
double  the  number  of  it  in  the  former. 

+  Brewster's  Edinburgh  Journal  of  Science, 
vol.  ii.  p.  322. 


728 


HERMAPHRODITISM. 


greater  or  less  extent  both  of  the  male  and 
female  sets  of  sexual  elements. 

This  doctrine  of  the  original  but  temporary 
double  sexed  character  of  all  embryos  derives, 
perhaps,  its  principal  support  from  a  source  to 
which  Dr.  Knox  does  not  advert, — we  mean 
the  existence  of  this  as  the  normal  and  perma- 
nent sexual  type  in  most  plants  and  in  many  of 
the  lower  orders  of  animals.  But  this  argument 
by  analogy  certainly  cannot  by  any  means  be 
considered  as  a  sufficient  basis  for  the  establish- 
ment of  so  broad  and  important  a  generalization 
in  philosophical  anatomy.  Dr.  Knox  himself 
seems  to  have  been  induced  to  adopt  the  idea 
principally  because  it  afforded  (when  once 
assumed  as  a  fact)  a  simple  and  elegant  solution, 
upon  the  laws  of  development,  of  the  occa- 
sional occurrence  of  cases  of  true  hermaphro- 
ditism ;  and  in  doing  so,  he  appears  to  have 
proceeded  upon  the  mode  in  which  most  such 
physiological  hypotheses  have  been  made,  viz. 
by  drawing  his  premises  from  his  deductions 
instead  of  his  deductions  from  his  premises. 
In  the  present  state,  however,  of  anatomical 
and  physiological  knowledge,  Dr.  Knox's  hypo- 
thesis, however  ingenious  in  itself,  is  one  which 
we  cannot  subscribe  to ;  for  first,  it  is  totally 
opposed  to  all  the  facts  which  have  been  ascer- 
tained, and  all  the  direct  observations  which 
have  been  made  by  Ratlike,  Meckel,  Muller, 
Valentin,  and  other  modern  anatomists  upon 
the  sexual  structure  of  the  embryos  of  the 
higher  animals  in  their  earliest  state;  and, 
secondly,  if  we  were  to  admit  it  merely  as  a 
probable  hypothesis,  it  is  still  even  in  this 
respect  equally  as  incapable  as  the  old  doctrine 
of  sexual  unity,  of  explaining  all  the  cases  of 
malformation  by  duplicity  of  the  genital  organs; 
for,  as  we  have  already  shewn,  there  are  some 
apparently  well-authenticated  instances  of  the 
existence  of  three  or  four  testicles  upon  the 
same  man,  or  three  or  four  ovaries  upon  the 
same  woman  ;  and  in  reference  to  all  such  cases 
we  would,  if  we  proceeded  upon  the  same 
data  and  the  same  line  of  argument  as  those 
adopted  by  Dr.  Knox,  be  obliged  to  suppose 
that  the  original  sexual  type  is  not,  as  he  ima- 
gines, double  only  as  respects  the  two  sexes, 
but  double  even  as  respects  each  sex,  and  that 
all  embryos  had  originally  not  simply  the  ele- 
ments of  two,  but  those  of  three  or  four 
testicles  and  ovaries.  In  explaining  such  cases 
as  those  to  which  we  allude,  Dr.  Knox,  on  his 
own  doctrine,  must  of  necessity  admit  the 
existence  of  a  malformation  by  duplicity  of  the 
sexual  organs  in  question  ;  and  if  we  grant  this 
in  regard  to  these  instances,  it  is  surely  unne- 
cessary to  invent  a  particular  and  gratuitous 
hypothesis  for  the  explanation  of  the  analogous 
anatomical  anormalities  observed  in  hermaph- 
roditism. At  present  we  must,  we  believe, 
merely  consider  the  occurrence  of  anomalous 
duplicity  of  the  sexual  organs,  and  of  various 
other  individual  parts  of  the  body,  as  so  many 
simple  empirical  facts,  of  which  we  cannot,  in 
the  existing  state  of  our  knowledge,  give  any 
satisfactory  explanation,  or,  in  other  words, 
which  we  cannot  reduce  to  any  more  simple  or 
general  fact;  though  from  the  success  which 


has  attended  the  labours  of  many  modern 
investigators  in  this  particular  department  of 
anatomy,  it  seems  to  us  not  irrational  to  hope 
that  ere  long  we  may  be  enabled  to  gain  much 
new  light  upon  the  question  of  double  her- 
maphroditism and  the  whole  subject  of  mal- 
formation by  duplicity. 

ANATOMICAL    DEGREE  OF  SEXUAL  DUPLICITY 
IN  HERMAPHRODITISM. 

Though  the  cases  which  we  have  brought 
forward  do  not  present  any  instances  of  such 
perfect  hermaphrodites  in  the  human  subject 
or  in  quadrupeds  as  those  which  are  represented 
upon  the  ancient  Greek  statues  and  medals,  * 
or  that  have  been  described  and  delineated  by 
Lycosthenes,  Pare,  Schenkius,  and  the  older 
authors  on  monstrosities,  they  yet  present  to 
us  a  sufficient  number  of  instances  in  which, 
in  accordance  with  the  definition  we  have  pre- 
viously given  of  true  hermaphroditism,  there 
actually  co-existed  upon  the  body  of  the  same 
individual  more  or  fewer  of  the  genital  organs 
both  of  the  male  and  female. 

From  the  relations  and  size  of  the  bony  pelvis, 
and  the  fact  of  the  penis  and  clitoris  being  re- 
petitions only  in  situation  and  structure  and 
organic  connections  of  each  other  in  the  two 
sexes,  it  is  useless  perhaps  to  expect  that  we 
should  ever  find  in  any  one  case  all  the  parts  of 
both  sexes  present  at  the  same  time.  For 
since  the  male  penis  is  only  a  magnified  condi- 
tion of  the  female  clitoris,  and  since  both  of  these 
organs  are  connected  by  the  same  anatomical 
relations  to  the  same  part  of  the  pelvis,  it 
would  almost  require  some  duplicity  in  the 
pelvic  bones  themselves  to  admit  of  the  simul- 
taneous presence  of  both  ;  and  in  no  authentic 
case  has  any  approach  to  their  co-existence  upon 
the  same  individual  been  observed. 

Various  authors  who  have  written  upon  the 
subject  of  hermaphroditism  have  gone  so  far 
as  to  endeavour  to  refer  all  instances  of  it  to 
some  one  or  other  of  those  varieties  that  we 
have  described  under  the  name  of  spurious. 
Thus,  dogmatizing  in  a  spirit  of  unphilosophical 
scepticism,  Parsonsf  and  Hill  J  have  endea- 
voured to  shew  that  all  reputed  hermaphro- 
dites are  only  malformed  females  having  a 
preternatural  development  of  the  clitoris,  and 
in  some  instances  with  the  ovaries  descended 
into  the  labia.    Others,  on  the  contrary,  as 

*  See  Winckelman,  Hist,  de  l'Art,  t.  i.  p.  364; 
and  Caylus,  Recueil  d'Antiquites,  t.  iii ;  Heinrich, 
Commentatio  qua  Hermaphroditorum  artis  antique 
operibus  illustrium,  origines  et  causae  explicantur. 
Hamburg,  1805.  IJlumenbach,  in  his  Specimen 
Hist.  Nat.  Antiq.  artis  ( Goetting,  1808),  mentions 
and  figures  (pi.  i.  f.  5,  p.  15),  a  small  ancient  sil- 
ver cast  or  impression  of  a  case  of  hypospadias  of 
the  male  genital  parts,  which  he  supposes  to  have 
formed  a  votive  offering  from  some  individual  mal- 
formed in  the  manner  represented. 

t  Enquiry  into  the  nature  of  Hermaphrodites, 
p.  145.  We  would  particularly  point  out  the  cases 
quoted  by  Dr.  Parsons  at  p.  14,  26,  30,  88,  95,  130, 
&c.  of  his  able  essay  as  directly  contradictory  of 
his  own  doctrine,  or  as  instances  of  hermaphroditic 
appearances  in  persons  not  of  the  female  but  of  the 
male  sex. 

|  Review  of  the  Philosophical  Transactions. 


HERMAPHRODITISM. 


729 


Professors  Osiander*  and  Fei!er,f  maintain 
with  equal  inaccuracy  that  every  supposed  in- 
stance of  hermaphroditism  is  referable  to  a 
hypospadic  state  of  the  penis  and  scrotum,  in 
persons  that  are  in  other  respects  essentially 
male. 

Various  physiologists,  again,  while  they  ad- 
mit the  occurrence  of  all  the  different  varieties 
of  spurious  hermaphroditism,  are  inclined  to 
deny  that  anv  such  combinations  of  male  and 
female  organs  upon  the  same  body  as  those 
which  constitute  our  several  varieties  of  true 
hermaphroditism,  are  ever  observed  to  occur 
in  the  human  subject,  or  among  the  higher 
classes  of  animals.f  In  despite  of  the  recent 
accumulation  of  new  and  authentic  cases,  Pro- 
fessor Muller  of  Berlin  is,  in  particular,  in  his 
excellent  treatise  on  the  development  of  the 
genital  organs,  published  in  1830,§  still  in- 
clined to  coincide  in  a  great  degree  in  this 
opinion.  This  distinguished  physiologist  does 
not  indeed,  as  some  have  done,  doubt  in  any 
degree  the  authenticity  of  the  recorded  cases, 
and  even  goes  so  far  as  to  admit  the  occasional 
occurrence  of  a  combination  of  male  and  female 
organs  upon  the  same  individual,  when  that 
combination  does  not  (as  in  lateral  and  trans- 
verse hermaphroditism)  imply  a  true  sexual 
duplicity  or  repetition  of  any  of  the  cor- 
responding male  and  female  parts ;  but  he 
doubts  altogether  the  probability  of  our  third 
division  of  double  or  complex  hermaphroditism, 
and  conceives  that  in  the  examination  of  the 
cases  referable  to  that  section  a  sufficient  degree 
of  attention  has  not  been  directed  to  the  ac- 
curate anatomical  distinction  of  the  particular 
parts  supposed  to  exist,  from  others  with  which 
it  is  possible  to  confound  them.  We  shall 
here,  therefore,  shortly  inquire  into  some  of  the 
principal  sources  of  fallacy  which  are  apt  to 
mislead  the  incautious  observer  in  the  examina- 
tion of  such  instances  as  those  to  which  we 
allude  ;  and  in  doing  so  we  shall  consider  the 
various  sources  of  error  in  an  order  conformable 
with  those  divisions  of  double  hermaphroditism 
that  we  have  previously  adopted, — speaking  of 
the  mistakes  which  may  be  committed  in  judg- 
ing of  the  supposed  co-existence,  1st,  of  a 
female  uterus,  and  male  vesicula;  seminales 
and  vasa  deferentia  ;  2d,  of  a  female  uterus 
and  male  testicles,  &c. ;  3d,  of  both  testicles 
and  ovaries. 

1 .  Fallacies  in  judging  of  the  addition  of 
male  seminal  ducts  to  a  female  tape  of  sexual 
organs. — That  form  of  sexual  duplicity  which 
we  have  formerly  described  as  consisting  in  the 
supposed  superaddition  of  male  vesiculae  semi- 
nales and  vasa  deferentia  to  an  organization  in 
other  respects  female,  appears  to  have  been 

*  Neue  Denkwuerdigk.  fur  Geburtshiilfe.  Bd.  i. 
n.  8. 

t  Ueber  Angeb.  mensliche  Misbildung.  Land- 
shut  1820. 

f  Thus  Portal,  Anat.  Med.  t.  v.  p.  474;  Haller, 
El.  Phys.  t.  viii.  p.  7,  "  merito  dubitatur  j" 
Voigtel,  Handbuch  der  Path.  Anat.  Bd.  iii.  s.  364; 
Lawrence,  Art.  Generation,  in  Rees's  Cyclopaedia. 

§  Bildunsgeschichte  der  Genitalien. 


hitherto  observed  principally,  or  indeed  only 
among  the  Ruminantia,  and  has  in  particular 
been  repeatedly  found  in  free-martin  cows.  In 
judging  of  the  reality  of  this  variety  of  herma- 
phroditic malformation  in  any  given  case,  there 
is  one  source  of  fallacy  that  requires  to  be  par- 
ticularly guarded  against,  and  the  consideration 
of  which  may  probably  go  far  to  explain  away 
most  of  the  recorded  examples  of  the  mal- 
formation. In  the  female  sexual  parts  of  some 
Ruminantia  and  Pachydermata,*  but  particu- 
larly in  the  domestic  cow  and  sow,  Dr.  Gaert- 
ner  of  Copenhagen  pointed  out  in  1822f  the 
existence  of  two  canals  or  ducts  which  have 
since  that  time  been  generally  described  under 
his  name.  On  each  side  of  the  body,  one  of 
these  ducts  arises  in  the  vicinity  of  the  ovary, 
or  near  the  fimbriated  extremity  of  the  Fallopian 
tube,  runs  dov."n  first  in  the  duplicature  of  the 
broad  ligament,  and  afterwards  in  the  sub- 
stance of  the  parietes  of  the  uterus  and  vagina, 
to  near  the  meatus  urinarius,  and  there  opens 
into  the  vaginal  cavity.  Each  duct  communi- 
cates with  several  small  glands,  follicles,  or 
cysts  that  are  scattered  along  its  course,  and 
which  perhaps  may  not  be  improperly  described 
as  diverticula  from  the  ducts  themselves.  Now 
when  we  consider  the  relations  of  those  imper- 
fect ducts  and  cysts  that  are  occasionally  ob- 
served in  the  free-martin  cow,  situated  along- 
each  side  of  the  defectively  developed  uterus, 
and  which  Mr.  Hunter  has  described  as  male 
vasa  deferentia  and  vesiculae  seminales,  it  seems 
to  us  not  at  all  improbable  that  these  supposed 
male  organs  are  only  in  reality  the  ducts  of 
Gaertner,  with  their  accompanying  follicles  or 
cysts  generally  perhaps  existing  in  a  morbidly 
developed  and  dilated  condition.  They  seem 
at  least  to  correspond  much  in  their  origin, 
course,  and  position  with  the  canals  and  cysts 
discovered  by  Gaertner ;  and  certainly  in  the 
present  state  of  our  knowledge  it  would  appear 
more  reasonable  to  refer  them  to  this  normal 
portion  of  the  female  structure,  than  to  regard 
them,  until  we  have  more  decided  evidence  on 
the  subject,  as  abnormal  male  organs,  and  as 
affording,  in  consequence,  an  example  of  sexual 
duplicity. 

In  the  course  of  the  preceding  pages  we 
have  had  occasion  to  allude  to  cases  in  the 
human  subject,  and  in  the  dog  and  sheep,  in 
which  vasa  deferentia  were  stated  to  have 
existed  in  the  same  individual  along  with 
Fallopian  tubes.  Whether,  in  any  of  these 
instances,  the  supposed  male  seminal  ducts 
were  merely  canals  analogous  to  those  described 
by  Gaertner  in  the  cow  and  sow,  we  shall  not 
take  it  upon  us  to  determine,  but  in  connection 
with  this  inquiry  it  is  interesting  to  remark  that 
Malpighi,  who  seems  to  have  been  well  ac- 
quainted with  the  existence  of  the  ducts  in  the 

*  M.  Delmas  seems  to  have  observed  a  somewhat 
similar  structure  in  the  Kangaroo.  (Ephem.  Medic, 
dc  Montpellier,  t.  v.  p  115.) 

t  Anatomisk  Beskrivclse  over  et  ved  Nogle  Dyr- 
Ai'ters  uterus  nndersogt  Glandulbst  organ,  &c.  Co- 
penhagen, 1822 ;  Edin.  Med.  and  Surg.  Journ. 
vol.  xxi.  p.  460. 


730 


HERMAPHRODITISM. 


cow,  has  suggested  that  they  may  also  exist  in 
a  more  obscurely  developed  state  in  the  human 
female,  and  may  perhaps  be  identified  with  the 
ramous  lacunae  described  by  De  Graaf,  Bar- 
tholin, Riolan,  &c. 

A.  C.  Baudelocque  has,  in  a  case  published 
in  the  Revue  Medicale  for  March  1826, 
described  a  human  uterus  which  contained  in 
its  parietes  a  canal  coming  from  the  right 
Fallopian  tube,  and  opening  upon  the  internal 
surface  of  the  cervix  uteri ;  and  Moureau  and 
Gardien  seem  to  have  met  with  a  second  (?) 
similar  instance.* 

Before  leaving  this  subject  of  the  probable 
source  of  fallacy  which  we  have  to  guard 
against  in  confounding  the  ducts  of  Gaertner 
with  the  male  seminal  canals,  it  is  necessary 
also  to  observe,  that  some  anatomists!  are  now 
inclined  to  consider  these  canals  as  the  perma- 
nent remains  of  the  ducts  of  those  Wolffian 
bodies  which  we  shall  presently  have  occasion 
to  allude  to  more  at  length,  as  forming  a  tem- 
porary type  of  structure  in  the  sexual  develop- 
ment of  the  early  embryo ;  and  certainly  the 
two  appear  to  accord  in  most  points  with 
respect  to  their  situation  and  course.  If,  how- 
ever, it  happens  that  further  and  more  accurate 
observations  prove  the  two  to  be  different,  then 
the  possible  permanent  state  of  the  ducts  of 
the  Wolffian  bodies  must  be  looked  upon  as 
affording  another  source  of  error,  by  which  we 
may  deceive  ourselves  in  judging  of  sexual 
duplicity  from  the  supposed  superaddition  of 
male  seminal  canals  to  a  female  sexual 
apparatus. 

2.  Fallacies  in  the  supposed  co-existence  of 
a  female  uterus  with  testicles  and  other  organs 
of  a  male  sexual  type. — We  have,  in  a  pre- 
vious part  of  this  communication,  adduced 
about  twenty  different  instances  in  the  human 
subject,  and  in  the  quadruped,  in  which  a 
female  uterus,  or  both  an  uterus  and  Fallopian 
tubes  were  described  as  having  been  found  upon 
the  bodies  of  individuals  that  were  in  other 
respects  essentially  males. 

In  reference  to  some  of  these  instances  it 
has  been  doubted  whether  the  sexual  organiza- 
tion of  the  malformed  animal  was  not  entirely 
male,  the  supposed  and  generally  imperfect 
uterus  being  conceived  to  be  formed  either  by 
a  morbid  dilatation  and  unfolding  of  the  sub- 
stance of  the  male  prostate  gland,  or  by  an 
abnormal  union  and  development  of  the  vesi- 
culoe  seininales.  Thus,  in  the  case  detailed  by 
Ackermann,  the  only  male  sexual  organ  that 
was  entirely  deficient  was  the  prostate,  and  the 
only  reputed  female  organ  which  was  present 
was  an  imperfect  cystiform  uterus  differing 
greatly  in  structure  from  the  form  of  this  organ 
in  the  infant,  and  having,  as  in  the  normal 
state  of  the  prostate,  the  vasa  deferentia  pene- 
trating through  its  substance  without  opening 
into  its  cavity,  and  ultimately  terminating  along 

*  Medical  Repository  for  1826,  p.  571. 

f  As  Jacobson  of  Copenhagen  in  Journal  de 
l'lnstitut,  t.  ii.  p.  160;  and  Die  Okenschen  Koerper, 
&c.    Copenhagen,  1830. 


with  it  in  the  posterior  part  of  the  urethra.  In 
the  analogous  instance  quoted  in  a  preceding 
page  from  Steghlener,  a  similar  arrangement  of 
parts  was  observed;  and  in  that  case  there  was, 
in  the  enlarged  ureters  and  renal  infundibula, 
sufficient  evidence  (as  we  shall  afterwards  point 
out  when  speaking  of  the  probable  causes  of 
hermaphroditism)  of  a  distending  power  having 
acted  upon  the  whole  internal  surface  of  the 
urinary  and  genital  organs,  and  with  so  great  a 
force  (we  may  in  the  meantime  allow)  as  to  be 
capable  of  producing  such  a  morbid  dilatation 
and  unfolding  of  the  substance  of  the  prostate 
as  the  doctrine  alluded  to  requires.  Such  an 
effect  would  be  the  more  liable  to  be  produced 
if  we  can  suppose  this  latter  organ  to  have  been 
disposed,  by  original  tenuity  of  its  coats,  or  by 
morbid  softening  or  other  diseased  st.ites  of  its 
tissues,  to  yield  more  easily  to  the  dilating 
power,  than  any  of  the  other  surfaces  to  which 
it  happened  to  be  applied.  At  the  same  time, 
however,  we  confess  that  we  conceive  it  unphi- 
losophical  to  endeavour  to  account  for  alt  the 
cases  which  we  have  previously  quoted  of  the 
addition  of  a  female  uterus  to  a  male  type  of 
sexual  organization  upon  this  mechanical  prin- 
ciple, or  to  attempt  to  explain  away,  in  the  mode 
we  have  just  referred  to,  the  evidence  which 
these  cases  afford  of  the  occasional  occurrence 
of  this  combination  as  a  true  form  of  sexual 
duplicity.  For  even  granting  that  the  instances 
given  by  Ackermann  and  Steghlener,  and  per- 
haps one  or  two  other  cases,  are  not  at  all 
satisfactory  in  regard  to  the  reputed  existence 
of  such  a  variety  of  sexual  duplicity,  and 
allowing,  what  seems  indeed  not  at  all  impro- 
bable, that  the  supposed  very  imperfect  uterus 
in  these  examples  was  merely  an  organ  formed 
by  a  dilatation  of  the  prostate  and  seminal 
ducts,  there  is  still  a  sufficient  abundance  of 
cases  left  to  which  this  explanation  cannot 
possibly  apply. 

Thus,  in  the  person  dissected  by  Petit,  the 
imperfect  uterus  was  furnished  with  two  per- 
forate Fallopian  tubes  of  three  and  a  half 
inches  in  length,  and  at  the  same  time  it  is 
distinctly  stated  that  not  only  the  prostate 
gland,  but  the  vesiculre  seminales  and  vasa 
deferentia  were  also  present.  The  vasa  defe- 
rentia, between  their  origin  from  the  testicles 
and  their  urethral  termination,  were  each  above 
seven  inches  long,  and  they  entered  the  urethra 
by  two  apertures  that  were  quite  distinct  and 
separate  from  the  orifice  of  the  uterus,  which 
opened  into  the  urethral  canal  at  a  point  placed 
between  the  neck  of  the  bladder  and  the 
prostate.  In  this  case  we  cannot  suppose  that 
the  uterus  and  Fallopian  tubes  were  formed  at 
the  expense  of  the  prostate  gland  or  male 
seminal  ducts,  as  they  and  all  the  other  male 
organs  were  present ;  and  consequently  we  can 
only  consider  the  female  organs  as  a  super- 
addition  to,  and  not  a  transformation  of  the 
male  structures;  or,  in  other  words,  we  must 
look  upon  the  above  as  an  instance  of  duplicity 
in  a  part  of  the  sexual  apparatus. 

The  same  reasoning  and  remarks  might  be 
shewn,  if  it  were  necessary,  to  apply  in  a  greater 


HERMAPHRODITISM. 


731 


or  less  degree  to  the  other  analogous  examples 
in  the  human  subject  given  by  Harvey  and 
Professor  Mayer,*  as  well  as  to  the  hermaphro- 
ditic sheep  described  by  Thomas,  and  the  diffe- 
rent cases  in  the  goat  mentioned  and  delineated 
by  Guilt  and  Mayer.  In  all  these  latter  cases 
in  the  quadruped,  the  male  organization  appears 
to  have  been  perfectly  developed,  the  testicles, 
epididymes,  vasa  deferentia,  and  vesiculae  semi- 
nales  being  present  in  all  of  them ;  and  in 
Thomas's  sheep  the  superadded  female  uterus 
shewed  internally  the  usual  characteristic  rugose 
structure,  while  its  cornua  terminated  in  two 
long  Fallopian  tubes.  In  Guilt's  goat  case  all 
the  internal  male  sexual  organs  were  found, 
with  the  exception  of  Cowper's  glands;  and 
yet  we  cannot  suppose  that  these  glands  could 
have  been  transformed  and  moulded  out  into 
that  distinct  and  hollow  uterus  with  its  two  very 
long  curved  cornua,  which  the  reporter  has  re- 
presented as  being  present ;  not  to  mention  the 
total  want  of  any  collateral  evidence  in  this  and 
in  the  other  cases  to  which  we  have  just  now 
referred,  of  any  dilating  power  having  acted 
upon  the  genital  or  urinary  organs  in  the  em- 
bryo. 

3.  Fallacies  in  the  supposed  co-existence  of 
testicles  and  ovaries. — In  several  of  those  in- 
stances in  which  there  has  been  supposed  to  be 
a  co-existence  of  both  testicles  and  ovaries  upon 
the  same  side  or  sides  of  the  body,  it  seems 
highly  probable  that  there  has  been  a  fallacy  in 
the  observation,  owing  to  a  want  of  knowledge 
of  some  anatomical  circumstances  that  are  liable 
to  lead  us  into  error  in  making  an  examination 
of  such  a  case. 

We  have  previously  had  occasion  to  allude 
to  the  existence  in  the  foetal  state  of  the  Wolffian 
bodies,  which  are  placed  one  along  each  side 
of  the  spine,  and  occupy  at  an  early  period  in 
the  embryo  a  great  part  of  the  cavity  of  the 
trunk.  These  bodies,  as  is  now  well  known 
from  the  investigations  of  Rathke,  Meckel, 
Midler,  Burdach,  and  others,  form  in  Mam- 
malia and  Birds  at  least,  and  equally  so  in 
both  sexes,  the  primordial  matrices  of  the  geni- 
tal and  urinary  organs  (see  article  Ovum),  and 
in  the  natural  course  of  development  altogether 
disappear  in  man  and  in  the  quadruped  during 
the  earlier  periods  of  development,  leaving  no 
vestige  of  their  presence  in  the  extra-uterine 
animal. 

This  particular  foetal  type  of  structure,  like 
every  other  temporary  type  of  the  embryo, 
may,  from  an  impediment  or  arrest  in  the  natu- 
ral course  of  the  changes  occurring  in  the  deve- 
lopment of  the  body  in  general,  or  of  the  genital 
organs  in  particular,  become,  we  have  every 
reason  to  believe,  occasionally  permanent  in 
one  or  more  of  its  parts,  and  thus  by  its  pre- 
sence in  the  animal  lead  us  to  suppose  that  a 
rudimentary  testicle  exists  in  an  otherwise  well- 
marked  female,  or,  on  the  other  hand,  that  an 
ovary  exists  in  an  otherwise  well-marked  male. 
Both  of  these  mistakes  will  be  the  more  apt  to 
be  committed  if  the  original  excretory  duct  of 

*  See  his  second  case  in  the  foetus  and  those  of 
the  two  adults  in  a  preceding  page. 


the  Wolffian  body  remains,  for  it  may  give  the 
appearance  of  the  addition  of  a  vas  deferens  to 
the  supposed  testicle,  or  of  a  Fallopian  tube  to 
the  supposed  ovary. 

The  error,  also,  of  confounding  a  permanent 
Wolffian  body  with  the  testicle  will  be  the 
more  liable  to  occur,  in  consequence  of  the 
former  body  being  naturally  composed  of  an 
accumulation  of  convoluted  diverticula  which 
might  be  readily  mistaken  by  an  incautious  ob- 
server for  the  seminiferous  ducts  of  the  latter. 

There  is  certainly  strong  cause  for  doubting 
whether,  in  some  of  the  cases  that  we  have  cited 
of  the  supposed  co-existence  of  testicles  and 
ovaries  upon  the  same  sides,  the  uniemoved 
Wolffian  bodies  and  their  ducts  had  not  either 
been  mistaken  for  testicles  and  vasa  deferentia, 
while  the  sexual  organization  was  otherwise 
truly  female,  or  for  ovaries  and  Fallopian  tubes, 
while  the  type  of  structure  was  in  other  respects 
strictly  that  of  the  male.    This  remark  may 
perhaps  with  confidence  be  applied,  for  ex- 
ample, to  the  case  of  the  free-martin  described 
by  Mr.  Hunter ;  and  in  this  and  in  most 
other  similar  instances  the  supposed  testicles 
and  ovaries  have  not  been  at  all  examined 
with  any  thing  like  sufficient  anatomical  ac- 
curacy.   At  the  same  time,  however,  it  ap- 
pears to  us  impossible  to  explain  away  all  the 
recorded  cases  of  the  supposed  co-existence  of 
testicles  and  ovaries  upon  this  principle.  In 
reference  to  this  point  we  would  particularly 
observe  that  the  consideration  of  the  relative 
position  occupied  by  the  reputed  testicles  and 
ovaries  may  perhaps  afford  us  an  useful  guide 
in  cases  of  doubt.    In  some  of  the  instances 
that  have  been  previously  cited,  the  relative 
situation  of  the  supposed  testicles  and  ovaries 
was  exactly  such  as  the  Wolffian  bodies  are 
known  to  bear  to  these  parts.    In  other  in- 
stances, however,  as  in  the  ape  described  by 
Dr.  Harlan,  the  relative  situation  in  which  the 
testicles  and  ovaries  were  found,  was  that  which 
they  occupy  in  the  perfectly  formed  male  and 
female  ;  and  in  such  a  case  as  this  it  would 
surely  be  over-sceptical,  and  at  the  same  time 
in  opposition  to  all  that  we  yet  know  of  the 
history  of  the  Wolffian  bodies,  to  suppose  that 
these  bodies  had  imitated  the  testicles  so  far  as 
to  move  out  of  their  original  locality  and  travel 
downwards  through  the  inguinal  rings.    At  the 
same  time  we  must  recollect  that  in  this  case 
the  distinctive  anatomical  structure  both  of  the 
testicles  and  ovaries  seems  to  have  been  satis- 
factorily made  out,  in  so  far  that  the  former  are 
described  as  "  perfectly  formed,"  and  the  latter 
as  having  "  minute  ova  visible  in  them."    "  The 
male  and  female  organs  of  generation,"  Dr. 
Harlan  adds,"  were  as  completely  perfected  as 
could  have  been  anticipated  in  so  young  an  in- 
dividual, and  resembled  those  of  other  indivi- 
duals of  a  similar  age."    Now  if  we  once  admit 
in  this,  or  in  any  one  other  particular  instance, 
that  the  evidence  of  the  co-existence  of  testicles 
and  ovaries  is  satisfactory,  then  certainly  we 
may  in  any  equivocal  case  be  entitled  to  doubt 
until  we  have  some  more  sufficient  criterion  for 
distinction  pointed  out,  whether  the  dubious 
double  bodies  that  we  may  meet  with  be  a 


732 


HERMAPHRODITISM. 


rudimentary  testicle  or  ovary  conjoined  with  an 
imperfect  Wolffian  body,  or  really  a  true  in- 
stance of  the  presence  of  both  testicles  and 
ovaries  upon  the  body  of  the  same  individual. 

PHYSIOLOGICAL   DEGREE  OF  SEXUAL  PERFEC- 
TION IN  HERMAPHRODITES. 

Among  those  lower  tribes  of  animals,  such  as 
the  Abranchial  Annelida,  Pteropoda,  &c.  that 
are  naturally  hermaphrodite,  every  individual 
is  in  itself  a  perfect  representation  of  the  species 
to  which  it  belongs.  In  the  higher  orders, 
however,  in  which  the  distinction  and  separa- 
tion of  the  sexes  comes  to  be  marked,  each  in- 
dividual being  either  solely  male  or  solely 
female,  can,  as  has  often  been  remarked,  be  re- 
garded only  as  representing  one-half  of  its 
entire  species.  In  most  instances  of  hermaph- 
roditism among  these  more  perfect  animals,  the 
malformed  being  does  not  even  attain  to  this 
degree  of  perfection,  but  is  in  general  so  defec- 
tively constituted  as  not  to  have  the  proper 
physiological  characters  and  attributes  of  either 
sex.  In  cases  of  spurious  hermaphroditism  it 
would  appear  that  sometimes,  though  the  co- 
pulative or  external  sexual  parts  are  greatly  and 
variously  malformed,  the  internal  or  proper  re- 
productive organs  are  developed  with  sufficient 
perfection  to  enable  them  to  perform  the  func- 
tions belonging  to  them.  We  have  very  little 
proof,  however,  that  in  any  instances  of  what 
we  have  described  as  true  hermaphroditism, 
the  apparatus  of  either  sex  is  even  formed  with 
such  anatomical  perfection  as  to  empower  the 
malformed  being  to  bear  a  successful  part  in 
the  reproductive  function.  Indeed  in  all,  or  in 
almost  all  cases  belonging  to  this  last  order  of 
hermaphroditism,  the  individual  who  is  the 
subject  of  the  malformation  may,  with  much 
more  than  poetical  truth,  be  described  both 
anatomically  and  physiologically,  as,  in  the 
words  of  Ovid, 

Concretus  sexu,  sed  non  perfectus  utroque, 
Ambiguo  venere,  neutro  potiundus  amore. 

There  is  on  record  one  remarkable  instance 
of  apparent  exception  to  this  general  observa- 
tion, a  notice  of  which  we  have  reserved  for 
this  place  on  account  of  the  want  of  any  such 
precise  knowledge  of  the  true  anatomical  pecu- 
liarities of  the  case  as  might  enable  us  to  refer 
it  to  the  section  which  it  ought  to  occupy  in 
our  classification.  The  case  to  which  we 
allude  was  described  by  Dr.  Hendy  of  New 
York,  in  a  letter  dated  from  Lisbon  in  1807, 
and  the  subject  of  it  was  a  Portuguese,  twenty- 
eight  years  old,  of  a  tall  and  slender  but  mas- 
culine figure*  "  The  penis  and  testicles,"  to 
adopt  the  words  of  Dr.  Hendy 's  own  narrative, 
"  with  their  common  covering  the  scrotum,  are 
in  the  usual  situation,  of  the  form  and  appear- 
ance, and  very  nearly  of  the  size  of  those  of  an 
adult.  The  praeputium  covers  the  glans  com- 
pletely, and  admits  of  being  partially  retracted. 
On  the  introduction  of  a  probe,  the  male  ure- 
thra appeared  to  be  pervious  about  a  third  of 
its  length,  beyond  which  the  resistance  to  its 
passage  was  insuperable  by  any  ordinary  justi- 

-  *  New  York  Medical  Repository,  vol.  xii.  p.  86. 


fiable  force.  There  is  a  tendency  to  the  growth 
of  a  beard,  which  is  kept  short  by  clipping 
with  scissors.  Thefemale  parts  do  not  difierfrom 
those  of  the  more  perfect  sex,  except  in  the  size 
of  the  labia,  which  are  not  so  prominent,  and 
also  that  the  whole  of  the  external  organs  ap- 
pear to  be  situated  nearer  the  rectum,  and  are 
not  surrounded  with  the  usual  quantity  of  hair. 
The  thighs  do  not  possess  the  tapering  fulness 
common  to  the  exquisitely  formed  female  ;  the 
ossa  ilii  are  less  expanded,  and  the  breasts  are 
very  small.  In  voice  and  manners  the  female 
predominates.  She  menstruates  regularly,  was 
twice  pregnant,  and  miscarried  in  the  third  arid 
fifth  months  of  gestation.  During  copulation 
the  penis  becomes  erect.  There  has  never  ex- 
isted an  inclination  for  commerce  with  the 
female  under  any  circumstances  of  excitement 
of  the  venereal  passion."  In  the  preceding 
case,  (if  we  may  confidently  trust  to  the  account 
given  of  it,)  we  have  ample  proof  of  the  exist- 
ence of  the  internal  female  sexual  organs  in  the 
circumstances  of  menstruation  and  impregna- 
tion taking  place  ;  and  at  the  same  time  there 
appears  considerable  evidence  for  believing 
that  some  of  the  male  organs  were  present. 
For  even  if  we  were  to  argue  that  the  bodies 
present  in  the  scrotum  or  united  labia  might  be 
ovaries  and  not  testicles,  and  that  the  supposed 
semi-perforate  penis  was  only  an  enlarged  cli- 
toris, still  the  masculine  figure  of  the  individual, 
the  imperfect  beard,  the  narrowness  of  the 
pelvis,  and  the  form  of  the  lower  extremities 
would  tend  to  indicate  the  probable  existence 
of  the  rudiments  of  some  male  organs ;  and  if 
we  go  so  far  as  to  admit  this,  we  must  further 
allow  the  present  to  be  an  instance  of  hermaph- 
roditism, in  which  one  of  the  sets  of  sexual 
organs  was  capable  of  assuming  their  appro- 
priate physiological  part  in  the  process  of  re- 
production, though  perhaps  unable,  if  we  may 
judge  from  abortion  having  twice  occurred,  of 
ultimately  perfecting  that  process. 

The  preceding  remarks  upon  the  functional 
reproductive  powers  of  reputed  true  hermaph- 
rodites have  been  meant  to  apply  only  to  the 
supposed  perfection  ofo?;e  order  of  their  sexual 
organs.  It  becomes  a  still  more  interesting 
question  whether  it  ever  occurs  that  in  any  ab- 
normal hermaphrodite  among  the  more  perfect 
tribes  of  animals,  both  kinds  of  sexual  parts 
may  be  found  in  so  perfectly  developed  a  state 
as  to  enable  the  individual  to  complete  the 
sexual  act  within  its  own  body ;  or,  in  other 
words,  to  impregnate  and  be  impregnated  by 
itself.  Though  we  have  assuredly  no  positive 
proof  to  furnish  *  that  a  hermaphrodite  so  phy- 
siologically perfect  has  ever  yet  been  observed, 
and  should  very  strongly  doubt  its  occurrence 

*  We  do  not  certainly  feel  entitled  to  place 
among  the  category  of  correct  observations  either 
the  alleged  case  given  by  Linneus  (Mangetus'  Bib- 
liotheca  Chirurg.  lib.  iv. )  of  a  sow  with  perfect  male 
organs  on  one  side,  and  a  womb  containing  several 
foetuses  on  the  opposite  ;  or  that  mentioned  by 
Faber  (Hernandez'  Nov.  Plant.  Anim.  Mexic. 
Histor.  p.  547)  and  quoted  by  Haller  and  JRudolphi, 
of  the  co-existence,  in  a  rat,  of  ovaries  and  a  uterus 
with  nine  foetuses,  along  with  complete  male 
organs. 


HERMAPHRODITISM. 


733 


from  the  almost  universal  imperfection,  in  an 
anatomical  point  of  view,  of  the  malformed  or- 
gans, yet  we  have,  on  the  other  hand,  no  very  ra- 
tional ground,  except  that  of  the  experience  of 
all  observers  up  to  tiie  present  date,  for  denying 
entirely  and  unconditionally  the  utter  possibi- 
lity of  it.  And  peihaps  we  should  look  upon 
this  possibility  with  a  less  degree  of  scepticism 
when  we  consider  that  a  double  hermaphrodi- 
tism exists  as  the  normal  sexual  condition  of 
some  of  the  lower  tribes  of  animated  beings, 
and  at  the  same  time  take  into  account  the  fact 
of  the  more  or  less  direct  communication  which 
has  been  generally  found  to  exist  between  the 
female  uterus  and  the  male  passages,  in  cases 
of  lateral  and  of  complex  hermaphroditism  in 
the  human  subject  and  in  quadrupeds. 

In  one  of  the  cases  of  hermaphroditism  in 
the  goat,  previously  quoted  from  Mayer,  and 
where  there  weie  present  two  male  testicles, 
epididymes,  vasa  deferentia,  and  vesiculse  semi- 
nales,  and  a  female  vagina,  uterus  and  Fallo- 
pian tubes,  with  a  body  at  the  abdominal  ex- 
tremity of  one  of  these  tubes  that  was  supposed 
by  Mayer  to  resemble  a  collection  of  Graafian 
vesicles,  the  male  vasa  deferentia  opened  into 
the  female  vagina;  and  its  cavity  with  that  of 
the  uterus,  and  of  all  the  male  sexual  canals, 
was  distended  with  a  whitish  fluid  of  the  odour 
and  colour  of  male  semen,  and  containing,  ac- 
cording to  Bergmann,  the  chemical  principle 
proper  to  that  secretion.  It  is  not,  therefore, 
altogether  without  some  appearance  of  founda- 
tion in  fact,  that  Mayer  has  added  to  the  history 
of  this  case  the  following  proolematical  remark  : 
"  Fuit  ergo  revera  hermaphroditus  semetipsum 
fcecundare  studens."* 

In  a  similar  strain  Dr.  Harlan  has  added  to 
the  account  that  he  has  given  of  the  very  com- 
plete case  of  hermaphroditism  already  men- 
tioned as  met  with  in  the  Borneo  ourang- 
outang,  the  following  observations  and  queries. 
"  Admitting,"  he  remarks,  "  what  in  reality 
appeared  to  be  the  fact,  that  all  the  essential 
organs  of  both  sexes  were  present  in  this  indi- 
vidual, had  the  subject  lived  to  adult  age,  most 
interesting  results  might  have  been  elicited. 
Could  not  the  animal  have  been  impregnated 
by  a  male  individual,  by  rupturing  the  mem- 
brane closing  the  vulva  ?  or  by  masturbation, 
might  not  the  animal  have  impregnated  itself? 
by  this  means  exciting  the  testicles  to  discharge 
their  seminal  liquor  into  its  own  vagina.  The 
imperfection  of  the  urethra  most  probably 
would  have  prevented  the  animal  from  ejecting 
the  semen  into  the  vagina  of  another  indivi- 
dual."! 

It  has  been  sometimes  urged  as  an  argument 
conclusively  illustrative  of  the  fact  of  a  double 
hermaphrodite  impregnating  itself,  that  in  the 
hermaphrodite  Gustrophoga  pini  described  by 
Scopoli,];  the  insect  is  stated  to  have  been  seen 
to  advance  its  penis  and  copulate  with  its  own 
female  organs ;  and  afterwards,  we  are  inform- 
ed, the  female  side  laid  eggs  from  which  young 

*  Icones,  &c.  p.  20. 

t  Medical  and  Physical  Researches,  pp.  23,  24. 
$  Introd.  ad  Hist.  Nat.  p.  416. 


caterpillars  were  produced.  Before,  however, 
admitting  this  case  to  present  an  incontroverti- 
ble instance  of  absolute  hermaphroditism,  with 
the  functions  of  the  two  sets  of  sexual  organs 
existing  in  a  perfect  condition  upon  the  same 
individual,  it  is  necessary  to  recollect  a  possible 
source  of  fallacy  in  this  circumstance,  that 
female  Gastrophagi  have  been  observed  to  lay 
fertile  eggs,  although  they  had  not  had  pre- 
viously any  connection  with  the  male,  as  re- 
marked by  Professor  Baster*  in  one  instance  in 
a  female  Gustropluiga  quercifolia,  and  in  ano- 
ther in  the  Gastrophaga  pini  by  Suckow.f  The 
same  fact  is  further  alleged  to  have  been  ob- 
served in  some  few  instances  by  Pallas,  Trevi- 
ranus,  Bernouilli,  and  others,!  in  regard  to  in- 
dividuals belonging  to  some  other  of  the  higher 
orders  of  insects  and  animals,  as  in  the  Lii/uoeus 
auriculariaS}  and  Helix  vivipara\\  among  Mol- 
lusca,  thus  bringing  them  in  this  respect  into 
analogy  with  the  Aphides  and  Cyprides. 

CAUSES  OF  HERMAPHRODITIC  MALFORMATION. 

As  yet  we  possess  very  little  accurate  know- 
ledge either  in  respect  to  the  mode  in  which 
the  determining  causes  of  hermaphroditic  mal- 
formation act,  or  the  nature  of  these  causes 
themselves. 

Most  of  the  varieties  of  spurious  herma- 
phroditism may,  as  we  have  just  explained, 
be  traced  to  an  arrest  in  the  development  of  the 
sexual  organs  at  one  or  other  period  of  their 
evolution,  in  consequence  of  which  some  of 
those  types  of  structure  in  these  parts  which 
were  intended  to  be  temporary  and  transitory 
only,  are  rendered  fixed  or  permanent  in  their 
character.  Our  knowledge  of  the  more  imme- 
diate causes  of  such  arrested  development  in 
these  and  in  other  individual  parts  and  organs 
of  the  body,  is  as  yet  extremely  limited,  and  for 
the  discussion  of  it  we  must  refer  to  another 
part  of  the  present  work,  (see  article  Mon- 
strosities). We  may,  however,  in  reference 
to  the  particular  forms  of  arrested  development 
observed  in  hermaphroditism,  remark  that  in 
consequence  of  the  great  influence  which,  as 
we  have  already  pointed  out,  is  exercised  by 
morbid  states  of  the  ovaries  and  testicles,  in 
retarding  or  preventing  the  evolution  of  the 
sexual  apparatus  and  characters  after  birth,  it 
has  been  suggested  with  considerable  probabi- 
lity by  Meckel^!  and  Isidore  St.  Hilaire,**  that 
in  their  ultimate  analysis  certain  cases  of  her- 
maphroditic malformation  may  be  traced  in  the 
course  of  their  causation  to  morbid  influences 
exercised  in  the  early  embryo,  at  a  period 
more  or  less  near  to  conception,  upon  the 
ovaries  or  testicles,  or  upon  those  organs  of  a 
neuter  or  yet  undetermined  sex  which  after- 
wards assume  the  structure  of  one  or  other  of 

*  Mem.  de  l'Acad.  Roy.  de  Berlin,  1772. 
t  Heusinger's  Zeitschrift  fiir  Organ.  Phys.  Bd.  ii. 
s.  263. 

t  Burmeister's  Entomology,  s.  204.  Burdach's 
Physiologie,  t.  i.  §  44,  4-8. 
«  Isis  for  1817,  p.  320. 
|]  Spallanzani,  Mem.  sur  la  Resp.  p.  268. 
II  Anat.  Geu.  t.  i.  p.  609. 
**  Hist,  des  Anomal.  de  l'Organiz.  t.  ii.  58. 


734 


HERMAPHRODITISM. 


these  bodies.  Further,  the  effects  which  this 
supposed  morbid  influence  exercises  directly 
upon  the  embryonic  ovaries  and  testicles,  and 
indirectly  through  them,  upon  the  rest  of  the 
genital  apparatus,  and  consequently  the  modi- 
fications of  sexual  structure  which  it  produces, 
may  possibly  be  much  varied  according-  to  its 
extent,  duration,  and  nature,  and  according  to 
the  particular  period  of  development  at  which  it 
comes  into  action.  It  is  evident  that  this  ex- 
planation of  hermaphroditism  can  only  refer 
to  the  varieties  of  the  malformation  which 
consist  of  an  imperfection  or  deficiency  in  the 
development,  and  cannot  apply  to  those  in- 
stances in  which  there  is  a  superaddition  of 
sexual  organs.  If,  however,  we  can  once 
satisfy  ourselves  that  any  set  of  cases  whatever 
are  traceable  to  a  morbid  action  affecting  the 
testicles  or  ovaries  of  the  early  embryo,  our 
investigations  into  the  causes  of  these  cases 
will  necessarily  be  much  simplified,  for  our 
inquiries  would  be  reduced  from  a  vague  and 
indefinite  search  after  the  production  of  a  num- 
ber of  anomalies  of  structure  affecting  several 
different  organs  at  the  same  time,  to  an  attempt 
to  trace  out  the  nature  of  those  morbid  condi- 
tions to  which  the  embryonic  testicles  and 
ovaries  were  subject,  and  which  were  capable 
of  so  far  changing  the  structure  and  action  of 
these  organs  as  to  give  rise  to  the  effects  in 
question.  Of  the  diseased  states,  however, 
to  which  the  reproductive  and  other  organs  of 
the  system  are  liable  during  the  progress  of  their 
early  development,  we  at  present  know  little  or 
nothing,  although  in  the  investigation  of  this 
subject  a  key,  we  believe,  may  possibly  be  yet 
found  to  the  explanation  of  many  of  those 
malformations  to  which  different  parts  of  the 
body  are  subject. 

Osiander*  and  Dugesf  have  suggested 
that  the  variety  of  spurious  hermaphroditism 
which  consists  of  a  division  of  the  peri- 
neeum  in  the  male,  may  be  produced  me- 
chanically in  the  embryo  by  the  preterna- 
tural accumulation  of  fluid  in  the  urinary 
canal,  on  account  of  an  imperforate  state  of 
the  urethra,  and  the  consequent  distension  and 
ultimate  rupture  of  the  urethra,  &c.  From 
cases  published  by  Sandifort,  Howship,  Bil- 
lard,  and  many  others,  we  are  now  fully  aware 
of  the  fact  that  all  the  urinary  canals  of  the 
fcetus  in  utero  are  occasionally  found  morbidly 
distended  with  a  fluid,  which,  according  to 
the  interesting  observations  of  Dr.  Robert  Lee.  X 
would  appear  to  possess  the  more  character- 
istic qualities  of  urine.  We  have  dissected 
one  case  in  which  the  dilated  foetal  bladder  was 
as  large  as  an  orange,  and  have  seen  in  the 
Anatomical  Museum  of  Dr.  William  Hunter 
at  Glasgow  the  preparation  of  another  instance 
in  which  the  bladder  of  a  full-grown  foetus 
was  dilated  to  the  size  of  that  of  the  adult 
subject.  In  one  case  mentioned  by  Dr.  Mer- 
riman,  the  distended  organ  contained  half  a 

*  Neue  Denkw.  fur  Aertzte  und  Geburtsh,  Bd.  i. 
t.  264,  267. 

t  Ephem.  Med.  de  Montpellier,  t.  v.  p.  17,  45, 
and  52. 

t  London  Med.-Chirurg.  Trans,  vol.  xix. 


pint  of  urine,*  and  in  another  detailed  by  Mr. 
Feam  it  was  capable  of  containing  as  much  as 
two  quarts  of  fluid.f 

It  is  not  impossible  that  the  causes  in  ques- 
tion,— namely,  the  obliteration  of  the  urethra 
and  the  consequent  distention  of  all  the  urinary 
passages,  and  probably  also  of  the  sexual 
canals  communicating  with  these  passages, — 
may  occasionally  produce  in  the  male  embryo 
a  re-opening  of  theperinaeal  fissure,  giving  thus 
to  the  external  parts  the  appearance  of  a  female 
vulva,  and  perhaps  at  the  same  time  may  lead 
to  the  retention  and  imperfect  development 
of  the  testicles  by  the  distention  of  their  ducts, 
and  the  unusual  compression  to  which  these 
organs  may  be  subjected.  Indeed  we  have 
satisfactory  evidence,  in  a  few  instances,  that 
such  a  cause  may  have  been  in  operation,  by 
our  detecting  the  other  acknowledged  effects  of 
the  urinary  accumulation  in  question, — such  as 
preternatural !y  dilated  ureters,  and  a  cystic 
form  of  the  infundibula  of  the  kidneys,  as  in 
a  case  of  hermaphroditism  given  by  Mayer,  in 
a  human  foetus,};  in  the  kid  described  by 
Haller,§  and  in  the  child  whose  case  we  have 
already  quoted  from  Steghlener.  (See  trans- 
verse hermaphroditism. ) 

At  the  same  time  the  total  absence  of  these 
collateral  proofs  in  most  other  cases  of  hypo- 
spadias, our  knowledge  of  the  fact  that  the 
perinseal  aperture  is  in  some  cases  never  shut, 
and  the  difficulty  of  conceiving  the  possibility 
of  its  being  re-opened  when  once  it  is  firmly 
closed,  are  perhaps  sufficient  to  shew  that  the 
cause  or  causes  alluded  to  produce  in  but  few 
if  any  instances  the  effect  here  attributed  to 
them. 

We  deem  it  not  uninteresting  to  point  out 
in  this  place,  under  the  question  of  the  origin  of 
hermaphroditic  malformations,  a  circumstance 
which  has  struck  us  in  considering  one  or  two 
of  the  cases  in  which  the  sexual  apparatus  of 
one  side  of  the  body  was  more  imperfectly 
developed  than  that  of  other,  viz.  that  the 
opposite  side  of  the  encephalon  was  at  the 
same  time  defectively  formed.  Thus  in  the 
case  of  Charles  Durge,  on  the  right  side  of 
whose  body  there  was  a  well-formed  testi- 
cle, and  on  the  left  an  imperfect  ovary,  the 
right  hemispheres  of  the  cerebrum  and  cere- 
bellum, but  particularly  of  the  latter,  were 
found  by  Professor  Mayer  to  be  smaller  and 
less  developed  than  the  left,  and  the  left  side  of 
the  occiput  was  externally  more  prominent 
than  the  right.  The  same  author,  in  the  ac- 
count of  his  case  of  hermaphroditism  in  a 
person  of  eighteen  years  of  age,  which  we 
have  previously  quoted,||  and  where  there  was 
an  imperfect  testicle,  &c.  on  the  right  side,  but 
no  trace  of  testicle  or  ovary  in  the  left,  inci- 
dentally mentions  that  the  right  side  of  the 
cranium  was  somewhat  prominent, — "  dextra 
pars  cranii  paullulo  prominet,"  in  correspon- 

*  London  Med.  and  Phys.  Journ.  vol.  xxv.  p. 
279. 

t  Lancet  for  1834-35,  p.  178. 
t  See  p.  8,  of  Icones,  &c. 

§  Comment.  Soc.  Reg.  Sc.  Gotting.  torn.  i.  p.  2. 
f|  Icones,  p.  12. 


HERMAPHRODITISM. 


735 


dence,  there  is  every  reason  to  believe,  with  a 
slight  predominance  in  size  in  the  hemispheres 
of  the  encephalon  of  the  same  side.  In  ad- 
ducing these  two  cases  we  do  not  wish  to  draw 
any  inference  with  regard  to  the  relation  of 
causation  between  the  size  and  development  of 
the  encephalic  mass  and  the  determination  of 
the  sex,  but  would  merely  point  out  the  facts 
themselves  in  the  meantime,  for  the  purpose  of 
drawing  attention  to  the  subject  in  the  observa- 
tion of  any  future  similar  instances  that  may 
happen  to  occur. 

In  connection  with  the  question  of  the  causes 
of  hermaphroditism,  it  is  interesting  to  remark 
that  in  some  instances  malformations  of  the 
genital  organs  giving  rise  to  appearances  of  her- 
maphroditism have  been  observed  both  to  be 
hereditary  in  particular  families,  and  in  other 
cases  to  occur  among  several  of  the  children  of 
the  same  parents.  Thus  Heuremann*  mentions 
an  example  of  a  family  the  females  of  which 
had  for  several  generations  given  birth  to  males 
who  were  all  affected  with  hypospadias  ;  and 
Lecatf  alleges  that  a  degree  of  hypospadias 
is  not  uncommon  among  families  in  Nor- 
mandy. In  Rust's  Magazine  an  instance  is 
related  of  a  degree  of  hypospadias  existing  in  a 
father  and  son.]  Baum,§  in  his  essay  on  con- 
genital fissures  of  the  urethra,  has  referred  to 
two  instances  of  the  existence  of  hypospadias 
in  brothers  of  the  same  family,  the  first  men- 
tioned by  Walreeht,||  and  the  second  by 
Gockel.1l  Sir  Everard  Home**  found  two 
cases  of  hypospadias  in  two  children  belonging 
to  the  same  parents.  Kauw  Boerhaaveff  men- 
tions an  example  of  four  hvpospadiac  brothers, 
and  Lepechin  another  instance  of  three.]:! 
Naegele  has  reported  a  case  in  which  two  male 
twins  were  both  hypospadic,§§  and  Katsky  |||| 
and  SaviardUK  have  mentioned  similar  in- 
stances. 

We  have  already,  when  treating  of  transverse 
hermaphroditism,  alluded  to  another  fact  long 
and  extensively  known  among  our  agriculturists, 
but  first  prominently  brought  before  the  notice 
of  physiologists  by  Mr.  Hunter,  that  the  free- 
martin  cow,  or  the  cow  that  is  born  a  co-twin 
with  a  male,  is  generally  barren  and  has  its 
sexual  organs  more  or  less  defectively  developed 
or  hermaphroditically  formed.***  In  three  dif- 

*  Medicin.  Beobaclit.  Bd.  ii.  s.  234,  and  Laroche 
sur  les  Monstrnsites  de  la  Face,  p.  30. 
t  Armaud,  1.  c.  p.  312. 

%  Magazin  fuer  die  Gesammte  Heilkundc,  Bd. 
xviii.  s.  1 13. 

§  De  fissuris  urethra?  virilis  fissuris  congenitis, 
p.  54. 

||  Burdach's  Metamorphose  des  Geschlechter,  p. 
52. 

f  Eph.  Nat.  Cur.  Dec.  ii.  Ann.  5.  (1686),  p.  85. 
**  Comp.  Anat.  iii.  p.  320. 

tt  Nov,  Com.  Acad.  Sc.  Petropolit.  t.  i.  p.  61. 
tab.  xi. 
It  Ibid.  t.  xvi.  p.  525. 
i§  Meckel's  Archiv.  Bd.  v.  s.  136. 
|f||  Acta  M.  Berol.  Dec.  1,  torn,  ix,  p.  61. 
ff  Observ.  Chirurg.  p.  284. 

***  From  the  Romans  employing  the  female  noun 
taura  to  signify  a  barren  cow,  it  has  been  ingeni- 
ously conjectured  that  they  w  re  not  unacquainted 
with  the  free-martin.    Thus  Columella  de  Re  Rus- 


ferent  instances  Mr.  Hunter  confirmed  the  fact 
of  the  anomalous  sexual  development  of  such 
animals  by  dissection;  and  Scarpa*  and 
Gurltf  have  published  some  additional  ob- 
servations and  cases.  We  have  lately  had 
an  opportunity  of  dissecting  the  sexual  parts  of 
two  adult  free-martins,  and  found  them,  as 
already  detailed,  formed  after  an  abnormal  and 
imperfect  sexual  type ;  and  our  friend  Dr. 
Allen  Thomson  made  some  years  ago  a  similar 
observation  upon  a  free-martin  twin  fcetal  calf. 
Cases,  however,  exceptional  to  the  general  fact 
of  the  sterility  and  imperfect  sexual  conforma- 
tion of  the  free-martin  twin  cow  are  not  unfre- 
quently  met  with.  Mr.  Hunter  found  the 
sexual  organs  of  a  free-martin  calf  that  died 
when  about  a  month  old  apparently  naturally 
constituted.  He  speaks  also  of  having  heard  of 
some  free-martins  that  were  so  perfectly  formed 
in  their  sexual  parts  as  to  be  capable  of 
breeding;  and  different  instances  of  their  fe- 
cundity have  been  published  by  Dr.  Moulson 
and  others];  since  the  time  that  Mr.  Hunter 
directed  attention  to  this  subject.  In  some 
pretty  extensive  inquiries  which  we  have  made 
in  regard  to  this  point  among  the  agriculturists 
of  the  Lothians,  we  have  learned  only  of  two 
instances  in  which  free-martins  proved  capable 
of  propagating,  and  such  cases  seem  to  be 
always  looked  upon  as  forming  exceptions  to 
the  general  rule. 

VVe  are  not  aware  that  among  other  uni- 
parous  domestic  animals,  as  the  goat,  mare, 
&c  ,  when  a  female  is  born  a  co-twin  with  a 
male,  this  female  is  sterile,  and  has  its  sexual 
organs  hermaphroditically  formed,  as  in  the 
free-martin  cow  ;  and  we  are  sufficiently  as- 
sured that  no  such  law  holds  with  regard  to 
twins  of  opposite  sexes  among  sheep.  Sir 
Everard  Home,  in  his  essay  on  monstrous  for- 
mations, §  mentions  that  in  warm  countries 
nurses  and  midwives  have  a  prejudice  that  such 
women  as  have  been  born  twins  with  males 
seldom  breed;  and  we  have  found  the  same 
prejudice  existing  to  a  considerable  degree 
among  the  lower  orders  in  Scotland.  Mr. 
Cribb,||  of  Cambridge,  published  in  1823  a 
short  paper  in  order  to  refute  this  notion  as  far 
as  regarded  the  human  subject.  He  refers  to 
the  histories  of  seven  women  who  had  been 
born  co-twins  with  males.  Six  of  these  had 
children,  and  the  remaining  seventh  subject 
alone  had  been  married  for  several  years 
without  any  issue.  We  have  ourselves  made 
a  series  of  extensive  inquiries  of  the  same  nature 

tica,  lib.  vi.  chap.  22,  speaks  of  "  tauras  which 
occupy  the  place  of  fertile  cows  ;"  and  Varro  in 
like  manner  (lib.  ii  cap.  5. )  states  that  "  the  cow 
which  is  barren  is  called  taura"  (quae  sterilis  est, 
taura  vocatur).  There  is  no  evidence,  however, 
that  they  were  acquainted  with  the  particular  cir- 
cumstances relative  to  birth  under  which  free-mar- 
tins are  produced. 

*  Mem.  della  Societa  Italiana,  t.  ii.  p.  846. 

f  Lerbuch  der  pathol.  Anat.  Bd.  ii.  s.  188. 

\  Loudon's  Magazine  of  Natural  History,  vol. 
v.  p.  765.  See  also  Youatt  on  Cattle,  p.  539, 
Farmers'  Magazine  for  Nov.  1806  and  Nov.  1807. 

&  Comp.  Anat.  vol.  iii.  p.  333-4. 

||  London  Med.  Repos.  vol.  xx.  p.  213. 


736 


HERMAPHRODITISM. 


as  those  published  by  Mr.  Cribb,  and  have 
obtained  authentic  information  regarding  forty- 
two  adult  married  females  who  had  been  born  as 
twins  with  males.  Of  these,  thirty-six  were 
mothers  of  families,  and  six  had  no  children, 
though  all  of  them  had  been  married  for  a 
number  of  years.  Two  of  the  females  who 
have  families  were  each  born  as  a  triplet  with 
two  males.*  In  the  Medical  Repository  for 
1827  (p.  350)  an  anonymous  author  has  men- 
tioned an  instance  of  quadruplets  consisting  of 
three  boys  and  a  girl,  who  were  all  reared  :  the 
female  afterwards  became  herself  the  mother  of 
triplets.  Limited  as  the  data  to  which  we 
here  allude  confessedly  are,  they  are  still  amply 
sufficient  to  show  that  in  by  far  the  majority  of 
cases  the  females  of  twins  of  opposite  sexes  are 
in  the  human  subject  actually  fertile,  and,  as 
some  of  the  cases  we  have  collected  show,  they 
are  occasionally  unusually  prolific. 

On  the  other  hand,  however,  it  may  be  con- 
sidered by  some  that  the  same  data  rather  tend 
in  a  slight  degree,  as  far  as  they  go,  to  support 
the  popular  prejudice  of  the  infecundity  in  a 
number  of  cases  of  the  female  twin,  and  her 
analogy  in  this  respect  with  the  free-martin 
cow ;  for  out  of  the  forty-two  instances  which 
we  have  mentioned,  we  find  six  in  which  the 
woman  has  had  no  children,  though  living  in 
wedlock  for  a  number  of  years,  or  one  out  of 
seven  of  the  marriages  of  such  women  has 
proved  an  unproductive  one, — a  proportion, 
we  believe,  considerably  above  the  average 
of  unproductive  marriages  in  society  in  general, 
or  among  women  of  any  other  class.  But 
perhaps,  before  drawing  any  very  decided 
conclusion  with  regard  to  this  point,  a  more 
extended  foundation  of  data  would  be  requisite 
than  any  we  have  hitherto  been  able  to  adduce, 
as  it  is  perfectly  possible  that  our  having  met 
with  six  exceptional  cases  may  be  a  mere 
matter  of  coincidence. 

As  to  the  cause  of  the  malformation  and 
consequent  infecundity  of  the  organs  of  gene- 
ration in  the  free-martin  cow,  we  will  not  ven- 
ture to  offer  any  conjecture  in  explanation  of  it. 
It  appears  to  us  to  be  one  of  the  strangest  facts 
in  the  whole  range  of  teratological  science, 
that  the  twin  existence  in  utero  of  a  male  along 
with  a  female  should  entail  upon  the  latter  so 
great  a  degree  of  malformation  in  its  sexual 
organs,  and  in  its  sexual  organs  only.  The 
circumstance  becomes  only  the  more  inexpli- 
cable when  we  consider  this  physiological  law 
to  be  confined  principally  or  entirely  to  the 
cow,  and  certainly  not  to  hold  with  regard  to 
sheep,  or  perhaps  any  other  uniparous  animal. 

The  curiosity  of  the  fact  also  becomes 
heightened  and  increased  when  we  recollect 
that  when  the  cow  or  any  other  uniparous  ani- 
mal has  twins  both  of  the  same  sex,  as  two 
males  or  two  females,  these  animals  are  always 
both  perfectly  formed  in  their  sexual  organiza- 
tion, and  both  capable  of  propagating.  In  the 
course  of  making  the  preceding  inquiries  after 

*  Notes  of  the  histories  of  these  cases  individu- 
ally were  read  to  a  meeting  of  the  Royal  Physical 
Society  of  Edinburgh  in  the  beginning  of  1837. 


females  born  co-twins  with  males  in  the  human 
subject,  we  have  had  a  very  great  number  of 
cases  of  purely  female  and  purely  male  twins 
mentioned  to  us,  who  had  grown  up  and  be- 
come married,  and  in  only  two  or  three  in- 
stances at  most  have  we  heard  of  an  unpro- 
ductive marriage  among  such  persons. 

Further,  we  may,  in  conclusion,  remark  that 
among  the  long  list  of  individual  cases  of  her- 
maphroditism in  the  human  subject  that  we 
have  had  occasion  to  cite,  we  find  only  one 
instance,  (Eschricht's  case  of  transverse  herma- 
phroditism,) in  which  the  malformed  being  is 
stated  to  have  been  a  twin.  Katsky,  however, 
Naegele,  and  Saviard  have  each,  as  before  stated, 
mentioned  a  case  in  which  both  twins  were 
hermaphroditically  formed  in  their  sexual  organs. 

HERMAPHRODITISM   IN   DOUBLE  MONSTERS. 

One  of  the  most  curious  facts  in  the  history 
of  double  monsters  is  the  great  rarity  of  an 
opposite  or  hermaphroditic  sexual  type  in 
their  two  component  bodies,  the  genital  organs 
of  both  bodies  being  almost  always  either  both 
female  or  both  male. 

Physiological  science  affords  us  at  present 
no  satisfactory  clue  to  the  explanation  of  this 
singular  circumstance.  From  two  cases  of 
double  monstrous  embryos  observed  in  the  egg 
of  the  domestic  fowl  by  Wolff*  and  Baer,f 
and  from  a  similar  case  met  with  in  the  egg  of 
the  goose  by  Dr.  Allen  Thomson,  it  appears 
certain  that  double  monsters  sometimes  originate 
upon  a  single  yolk,  probably  in  consequence  of 
the  existence  of  two  cicatricula?  upon  this  yolk,J 
or  of  two  germinal  points  (or  two  of  the  vesi- 
cles of  Purkinje  and  Wagner)  upon  a  single 
cicatricula.  In  such  a  case  the  two  bodies  of 
the  double  monster  are  so  early  and  intimately 
united  together  as  to  form,  almost  from  the 
commencement  of  development,  a  single  sys- 
tem ;  and  therefore  the  fact  of  the  uniformity 
of  their  sexual  character  is  the  less  remarkable. 
But  in  other  instances  when  the  double  mon- 
ster originates  (as  from  the  phenomena  of  in- 
cubation in  double-yolked  eggs  we  know  to  be 
frequently  the  case,)  on  two  separate  yolks  or  in 
two  separate  embryos  becoming  fused  or  united 
together,  at  a  more  advanced  stage  of  develop- 
ment, it  appears  more  extraordinary  that  the 
sexes  of  the  two  conjoined  foetuses  should  be 
so  constantly  uniform  as  they  seem  to  be  in 
monsters  perfectly  double.  This  uniformity 
only  becomes  the  more  singular  when  we  re- 
flect that  twin  children  are  not  at  all  unfrequently 
of  opposite  sexes.§ 

*  Nov.  Comment.  Acad.  Petropolit.  torn.  xiv.  p. 
456. 

t  Meckel's  Archiv.  fur  Physiologie,  &c.  for  1827, 
p.  576. 

\  We  have  in  our  possession  a  preparation,  taken 
from  a  duck's  egg,  in  which  two  full-grown  futuses 
are  developed  on  opposite  sides  of  a  single  yolk  of 
the  common  size. 

§  In  the  Edinburgh  Lying-in  Hospital  forty-six 
cases  of  twins  occurred  from  1823  to  1836,  both 
years  inclusive.  In  seventeen  of  these  cases  the 
two  children  were  both  females  ;  in  sixteen  both 
males  ;  and  in  the  remaining  thirteen  instances  one 
child  was  male  and  the  other  female.    We  know  of 


HERMAPHRODITISM. 


737 


The  fact  itself,  however  we  may  explain  it, 
of  the  comparatively  extreme  rarity  of  both 
male  and  female  sexual  organs  upon  double 
monsters  seems  sufficiently  established  by  va- 
rious careful  investigations  made  into  the  sub- 
ject. Thus  out  of  forty-two  perfectly  double 
monsters  which  Haller*  was  able  to  collect  at 
the  time  at  which  he  wrote,  there  were  only 
two  that  were  supposed  to  be  of  double  sex, 
or,  in  other  words,  that  had  one  body  male, 
and  the  other  female.  Among  double-headed 
monsters,  with  single  lower  extremities,  he 
found  an  hermaphroditic  type  more  common, 
arid  adduces  three  examples  of  it. 

In  re-investigating  this  matter,  the  late  Pro- 
fessor Meckelf  could  discover  among  the  nu- 
merous class  of  monsters  with  perfectly  double 
bodies  united  anteriorly  or  laterally  by  the  tho- 
rax and  abdomen,  only  one  very  doubtful  case 
of  exception  to  the  above  general  fact.  In  the 
class  of  double  monsters  united  in  the  region 
of  the  pelvis  he  mentions  two  exceptional 
cases  from  Valentin'J  and  IJasenest  ;§  of  double- 
headed  monsters  with  single  bodies,  he  quotes 
three  similar  eases  from  Lemery,||  Bacher,5f 
and  Bilsius  ;**  and  of  monsters  with  a  single 
head  and  double  body  he  adduces  two  cases 
from  BrissKusff  ai1d  Condamine,JJ  in  which 
in  a  like  manner  one  body  of  the  monster  was 
supposed  to  have  female,  and  the  other  male 
sexual  organs.  Several  of  these  cases,  how- 
ever, certainly  rest  upon  too  doubtful  authority 
and  insufficient  observation. 

Isidore  St.  Hilaire  has  still  further  extended 
the  data  on  which  the  above  general  fact  is 
founded,  by  shewing  that  the  same  uniformity 
of  sex  holds  good  with  respect  to  double  para- 
sitical monsters,§§  and  even  in  monstrosities 
double  by  inclusion.  Thus  out  of  this  last  in- 
teresting class  of  double  monsters,  he  alludes|||| 
to  ten  distinct  cases  in  which  the  sex  of  the 
included  being  was  ascertained.  In  six  out  of 
these  ten  cases  the  includingand  included  body 
were  both  male;  and  in  the  other  four  they 
were  both  female. 

On  the  whole,  therefore,  we  must  consider 
as  founded  on  a  proper  induction  from  the  ex- 
isting data,  the  axiom  of  Meckel,—"  Sexuum 
diversorum  indicia  in  eodem  organismo,  quan- 
tumvis  duplicitate  peccet,  non  dari,  sed  unum 
tantum  observari."H1[  But  while  all  the  data 
hitherto  collected  with  regard  to  this  subject 

one  family  in  the  different  branches  of  which 
twelve  pairs  of  twins  have  been  born  within  three 
generations.  In  eleven  out  of  these  twelve  pairs 
the  co-twins  have  been  of  opposite  sexes. 

*  Opusc.  Anat.  (1751.)  p.  176. 

t  De  Duplicitate  Monstrosa,  p.  21. 

X  Eph.  Nat.  Cur.  Dec.  ii.  Ann.  iii.  p.  190. 

6  Comment.  Lit.  Norimb.  (1743,)  p.  58. 

||  Mem.  de  l'Acad.  des  Sc.  de  Paris,  for  1724. 

t  Roux'  Jour,  de  Med.  (1788,)  p.  483. 

**  Blankaart's  Coll.  Med.  &c.  (1680.) 

tt  Six  Observat.  de  M.  Brisseau,  (Paris,  1734,) 
p.  33.  V        '  ' 

XX  Mem.  de  l'Acad.  des  Sc.  (1733.)  p.  401, 

$§  Hist,  des  Anomal.  de  l'Organiz.  torn,  iii,  pp. 
235  and  386. 

IHI  lb.  p.  311. 

ff  De  Duplic.  Monst.  p.  21. 

VOL.  II. 


would  seem  to  point  it  thus  out  as  one  of  the 
most  constant  and  best  ascertained  laws  in  te- 
ratology, still  we  are  not  altogether  disposed  to 
consider  it  with  Zeviani*  and  Lesauvagef  as 
subject  to  no  exceptions  whatever.  In  the 
study  of  monstrosities,  as  in  the  study  of  other 
departments  of  medical  science,  we  find  many 
general,  but  no  universal  laws. 

Bibliography. — Affaitat  ( J.),  De  hermaphro- 
ditis,  Venct.  1549.  Columbus,  De  re  anatomica, 
lib.  xv.  Venet.  1559.  Bauhin  ( Caspar ),  De  her- 
maphroditorum  monstrorumque  partium  natura. 
Francof.  1609.  Sehenkius  ( J.  G. ),  Monstroium 
historia  meroorabilis,  Frankf.  1609.  Riolan,  Dis- 
cours  sur  les  hermaphrodites,  Paris,  1614.  Zac- 
chias,  Questiones  medico-legales,  lib.  vii.  Frankf. 
1657.  Palfyn,  Licetus' Traite  des  monstres.  Leid. 
1708.  Parsons,  A  mechanical  and  critical  inquiry 
into  the  nature  of  hermaphrodites,  Phil.  Trans. 
No.  xli.  and8vo.  London, 1741.  Buryhard,  Gruend- 
liche  Nachrict  von  einem  Hermaphroditen,  Bresl. 
1743.  Mertrud,  Dissertation  sur  la  fameuse  her- 
maphrodite, &c.  Paris,  1749.  3Iorand,  De  her- 
maphroditis,  Paris,  1749.  Arnuud,  Treatise  on 
hermaphrodites,  London,  1750  ;  also  in  Memoires 
de  Chirurgie,  torn.  i.  London  and  Paris,  1768. 
Haller,  Commentatio  de  hermaphroditis,  et  an 
dentur?  in  Comment.  Societ.  Rog.  Sc.  Gottin- 
gensis,  torn.  i.  p.  1-26.  Gotting.  1752  ;  and  lb. 
in  his  Opera  Minora,  torn.  ii.  Lusan.  1764.  Guil- 
tier, Observations  sur  l'histoire  naturelle,  &c. 
p.  16,  &c.  Paris,  1752.  Ferrein,  Sur  le  veritable 
sexe  de  ceux  qu'on  appelle  hermaphrodites ;  in 
Mem.  de  l'Acad  des  Sciences,  1757.  Hunter  (J.J, 
Account  of  a  Free-martin,  Philos.  Trans.  1779  ; 
and  Animal  Economy,  p.  55.  London,  1792;  or  in 
the  recent  edition  by  Owen,  1838.  Seiler,  Observ. 
nonnul.  de  Testiculorum  Descensu  et  Part.  Genit. 
Anomalis,  Leipzig,  1787.  Osiander,  Ueber  die 
Geschlechtsverwechselungen  Neugeborner  Kinder, 
in  his  Dcnkwurdigkeiten  f  ur  Geburtshiilfe,  Bd.  II. 
s.  462.  Gotting.  1795,  and  in  the  NeueDenkwurdigk, 
Bd.I.  s.  245.  YVrisberg,  De  Singulari  Deformitate 
Genitalium  in  puero  Hermaphroditum  Mentiente, 
Gotting.  1796;  and  in  his  Comment.  Medici,  Phy- 
siolog.  &c.  Argumenti.  Gotting.  1800,  p.  504-551. 
Pinel  (Ph.),  Vices  de  conformation  des  parties 
genitales,  &c.  in  Mem.  de  la  Soc.  Med.  d'Emulat. 
torn.  iv.  p.  234.  Paris,  1796.  Movreau  de  la  Sartlie, 
Quelques  considerations  sur  I'hermaphrodisme, 
ibid.  torn.  i.  p.  243  ;  also  in  his  Histoire  Naturelle 
de  laFemme,  torn.  i.  p.  211.  Paris,  1803.  Pietsch, 
Gedanken  von  den  Zwittern,  in  the  old  Hamburgh 
Magazin.  Bd.  IV;  s.  538.  Home  ( Ev.J,  Dissec- 
tion of  an  hermaphrodite  dog,  and  Obs.  on  herma- 
phrodites in  Philos.  Trans.  1795 ;  On  animals 
preternaturally  formed,  Lect.  on  Comp.  Anat. 
vol.  iii.  London,  1823.  Voigtel,  Handb.  der  Pathol. 
Anat.  Bd.  III.  Halle,  1805.  Achermann,  Infantis 
androgyni  hist,  et  iconog.  Jena,  1805.  Schuberth, 
Von  Unterschiede  der  beiden  Geschlechtcr,  in  his 
Allgem.  Gesichte  des  Lebens.  Th.  I.  Leipz.  1806. 
Schneider,  Der  Hermaphtoditismus,  in  Kopp's 
Jahrb.  der  Staatsarzneikunde,  p.  193,  1809. 
Meckel,  Ueber  die  Zwittcrbildung,  in  Rcil's  Archiv 
fuer  die  Physiol.  Bd.  XI.  Halle,  1812;  Handb. 
der  Pathol.  Anat.  Bd.  II.  Leipz.  1816;  System 
der  Vergleich.  Anatomie,  Halle,  1821.  Burduch, 
Metamorphose  der  Geschlechter,  in  Anatom.  Un- 
tersuchungen,  Leipzig,  1814  ;  Physiologie,  Bd.  I. 
Leipzig,  1826.  Metzyer,  Syst.  der  Gerichtl.  Arz- 
neywiss.  Konigsb.  1814.  Marc,  Bulletin  des  Sc. 
Medicales,  torn.  viii.  p.  179  &  245;  Articles  on  her- 
maphrodites in  the  Diction,  des  Sciences  Medicales, 
torn.  xxi.  p.  36-121,  Paris,  1817;  and  Diet,  de 
Medecine,  torn.  xi.  p.  91,    lb.  1824.  Steghlener, 

*  Mem.  delta  Soc.  Italian,  torn.  ix.  p.  521. 
t  Mem.  sur  les  Monstr.  par  Inclusion  (Caen, 
1829)  ;  or  Archiv.  Gen.  de  Med.  torn.  xxv.  p.  140. 

3  c 


738 


HERNIA. 


De  hermaphroditorum  Natura,  Leipa.  ct  Bamb. 
1817."  Virey,  Article  hermaphrodite  ou  Androgyne, 
in  Nouveau  Diction.  d'Histoire  "Naturelle,  Paris, 
1817.  Jacoby,  De  Mammalibus  Hermaphroditis 
alterno  latere  in  sexum  contrarium  vergentibus, 
iierlin,  1818.  Lawrence,  Article  Generation,  in 
Roes'  Cyclopaedia,  vol.  xvi.  London,  1819.  Feiler, 
Ueber  Angeborne  Menschliche  Missbildungen,  &c. 
Landshut,  1820.  Pierquin,  Cas  d'hermaphro- 
disme,  Montpell.  1823.  Henke,  Untersuchungen 
ueber  Hermaphroditen,  Gerichtliche  Medicin, 
Berlin,  1824.  Penchienati,  Observat.  sur  quelques 
pretendus  hermaphrodites,  Mem.  de  I'Acad.  de 
Turin,  torn.  x.  Rudolph!,  Beschreib.  einer  selt. 
Menschlichen  Zwitterbildung,  &c. ;  Abhand.  der 
Kdnigl.  Akad.  der  Wissens.  zu  Berlin  fur  1825. 
Berl.  1828.  Lippi,  Dissert.  Anatomico-Zootomico- 
Fisiologiehe,  &c.  Firenze,  1826.  Duges,  Mem. 
sur  riiermaphrodistne,  in  Ephemerides  Medicales 
de  Montpellier,  torn.  i.  Montp.  1827.  Knox, 
Outline  of  a  theory  of  herraaphrodism,  in  Brew- 
ster's Edinburgh  Journal  of  Science,  vol.  ii.  p.  322. 
Edinb.  1830.  Mutter,  Bildungsgeschichte  der 
Genitalien,  Dusseldoif,  1830.  Gurlt,  Lehrb.  der 
Patholog.  Anat.  der  Haus-Saugthiere.  Bd.  II. 
Berlin,  1831.  Mayer,  Icones  Selectae  prseparat. 
Mu^ei  Anatom.  Bonnensis  ;  Decas  Hermaphrodi- 
torum,  p.  8.  Bonn.  1831  ;  and  Walther's  and 
Graefe's  Journal,  &c.  Bd.  XVII.  Beatty,  Article 
Doubtful  Sex,  in  Cyclopaedia  of  Practical  Med. 
London,  1833.  Beck,  Medical  Jurisprudence, 
chap.  iv.  p.  69-81,  Doubtful  Sex,  London,  1836. 
Isidore  St.  Hiluire,  Histoire  des  Anomalies  de 
l'orgauization,  &c.  Paris,  1836.  Barry,  On  the 
Unity  of  Structure  in  the  Animal  Kingdom,  and 
in  Jamieson's  Edinb.  New  Philos.  Journ.  for  April, 
1837.    See  also  the  references  in  the  foot-notes. 

(James  Y.  Simpson.) 

HERNIA  (in  morbid  anatomy).  The  pro- 
trusion of  any  viscus  from  the  cavity  in  which 
it  ought  naturally  to  be  contained  is  termed  a 
hernia,  and  thus  the  apparent  escape  of  any 
part  from  any  of  the  great  cavities  of  the  body 
may  seem  to  constitute  the  disease  :  still,  how- 
ever, as  the  real  existence  of  cerebral  or  thoracic 
ruptures  rests  upon  very  doubtful  authority  and 
is  extremely  questionable,  and  as  abdominal 
protrusions  are  unfortunately  equally  palpable 
and  frequent,  the  application  of  the  term  is 
usually  limited  to  them.  To  this  frequency 
many  causes  seem  to  contribute.  In  the  walls 
of  the  abdomen  there  are  three  remarkable 
natural  openings,  or  perhaps  it  would  be  more 
correct  to  say,  there  are  three  situations  so  weak 
and  unprotected  that  they  easily  yield  and  per- 
mit the  escape  of  any  viscus  that  may  be  di- 
rected against  them  with  even  a  moderate  de- 
gree of  force :  these  are,  the  umbilicus,  through 
which  during  foetal  life  the  umbilical  cord 
passes;  the  inguinal  canal,  which  allows  the 
passage  of  the  spermatic  cord  in  the  male,  and 
the  round  ligament  of  the  uterus  in  the  female  ; 
and  the  crural  ring,  which  transmits  the  great 
bloodvessels  to  the  thigh  and  lower  extremity. 
The  nature  of  the  walls  too,  which  are  princi- 
pally composed  of  muscle,  and  the  condition  of 
the  viscera  within,  loose,  liable  to  change  of 
size  and  situation,  and  subject  to  irregular  pres- 
sure by  the  contractions  of  these  muscular  walls, 
dispose  to  the  occurrence  of  the  disease  in  any 
of  these  situations,  where  the  resistance  to  such 
pressure  is  but  feeble.  Hence  hernia?  are  most 
frequently  met  with  at  one  of  the  places  al- 


ready mentioned,— the  umbilicus  and  the  ingui- 
nal  and  femoral  canals.  But  there  are  other 
situations*  at  which  protrusions  may  possibly 
take  place,  although  fortunately  they  are  infre- 
quent, such  as,  at  the  side  of  the  ensiform  car- 
tilage, at  the  obturator  foramen,  at  the  sacro- 
ischiatic  notch,  and  between  the  vagina  and 
rectum  in  the  female.  It  is  also  evident  that 
if  the  muscles  or  tendons  of  the  diaphragm 
are  wounded,  some  portions  of  the  contents  of 
the  abdomen  may  escape,  thus  constituting  the 
varieties  of  ventral  and  phrenic  hernise.  Ac- 
cordingly the  forms  of  this  disease  have  been 
arranged  and  named  from  the  different  places  at 
which  they  occur, — an  arrangement  of  the 
greatest  practical  importance ;  for  as  the  struc- 
ture, the  size,  and  shape  of  each  aperture  must 
exert  a  peculiar  influence  on  the  condition  of 
the  protruded  viscus,  on  its  liability  to  become 
incarcerated,  on  the  possibility  of  its  being 
returned,  on  the  steps  to  be  adopted  for  this 
purpose,  and  above  all  on  the  safety  and  suc- 
cess of  an  operation  should  such  be  necessary, 
a  knowledge  of  each  of  these  in  connexion  with 
hernia  is  absolutely  indispensable. 

Besides  this  division  of  hernia  as  to  situ- 
ation, there  is  another  of  very  considerable  im- 
portance derived  from  the  nature  of  the  viscus 
displaced:  thus  in  abdominal  ruptures  the  con- 
tents of  the  tumour  may  be  intestine  alone,  in 
which  case  it  is  called  enterocele ;  or  omentum 
alone,  the  epiplocel'e ;  or  both  these  may  be 
engaged,  constituting  the  enter v-epiplocele. 
There  is  not  a  viscus  in  the  abdomen  or  pelvis, 
excepting  perhaps  only  the  pancreas  and  kid- 
neys, that  has  not  at  one  time  or  another 
formed  the  contents  of  a  rupture.  The  stomach 
has  been  partially  displaced  through  the  dia- 
phragm, or  pushed  through  the  walls  of  the  ab- 
domen :  the  duodenum  has  formed  part  of  a 
ventral  or  umbilical  hernia :  the  jejunum  or 
ileum  are  very  likely  to  be  protruded  in  any 
situation :  the  omentum  is  often  displaced, 
particularly  in  inguinal  hernia;  at  the  left  side  : 
the  large  intestines  from  being  more  fixed  are 
not  so  frequently  thrust  out,  yet  the  ccecum  and 
colon  are  but  too  often  found  among  the  con- 
tents of  a  rupture.  1  have  seen  a  large  portion 
of  the  liver  in  an  umbilical  hernia  of  the  infant : 
Verdierf  relates  numerous  cases  of  hernia  of 
the  urinary  bladder  ;  and  PottJ  mentions  one 
which  renders  it  nearly  certain  that  the  ovaria 
in  females  may  suffer  in  a  similar  manner. 
However,  the  natural  situation  of  any  viscus 
within  the  abdomen  is  but  an  uncertain  cri- 
terion by  which  to  judge  of  the  contents  of  a 
hernia  in  its  vicinity.  The  strangest  displace- 
ments have  been  observed  occasionally  in  the 
examination  of  this  disease :  thus  the  sigm#i^ 
flexure  of  the  colon-  has  been  protruded  at  the 
right  side,  and  the  ccecum  and  valve  of  th'suleJUTT-. 
at#the  left.*  In  all  large  and  old  hqrni's  Hie 
parts  are  dragged  out  of  their  proper  situations, 

-A  '  * 

\    \  V 

*  Sur  plusieurs  hemies  singulieres.  Garengeot, 
Memoires  de  l'Academie  Royale  de  Chir.  torn.  iii. 
p.  336.    Paris  edit,  in  15  vols.  1771. 

t  Mem.  de  I'Acad.  Royale  Je  Chir.  torn.  iv.  p.  1. 

f  Pott's  Works,  by  Earle,  vol.  ii.  p.  210. 


HERNIA. 


739 


and,  their  appearances  on  dissection  and  rela- 
tive positions  are  often  such  as  no  one  from 
anatomical  knowledge  alone  could  ever  have 
suspected  to  be  possible. 

In  all  forms  of  abdominal  hernia  excepting 
those  only  which  immediately  supervene  on 
penetrating  wounds,  the  contents  of  the  rupture 
are  lodged  within  a  pouch  or  bag  termed  the 
hernial  sue,  which  is  formed  of  the  peritoneum. 
This  membrane  lines  the  entire  cavity  so  per- 
fectly and  completely  that  nothing  can  pass  out 
from  it  without  the  membrane  also  participating 
in  the  derangement  and  being  pushed  out  before 
the  displaced  viscus.  Once  formed,  this  sac 
is  rarely  capable  of  being  replaced  or  returned 
into  the  cavity  of  the  abdomen  ;  never  unless 
the  hernia  is  small  and  recent,  and  "  the  cel- 
lular substance  accompanying  it  and  the  sper- 
matic cord  through  the  ring  has  not  lost  its 
natural  elasticity  and  contractility."  *  Many 
surgeons  have  doubted  the  possibility  of  such 
an  occurrence  at  any  period,-)-  but  the  fact  has 
been  demonstrated  by  dissection,  and  still  more 
forcibly  by  the  circumstance  of  the  hernia 
having  been  thus  strangulated  within  the  ab- 
domen when  the  sac  has  been  returned  along 
with  it.  However,  as  I  have  said,  the  sac  when 
once  formed  is  rarely  capable  of  being  replaced, 
nor  does  it  long  remain  in  this  abnormal  situation 
without  undergoing  some  change  in  its  patho- 
logical condition — a  change  which  it  is  not 
always  easy  satisfactorily  to  explain.  In  small 
hernia?  that  have  recently  come  down,  the  struc- 
ture of  the  sac  differs  in  nothing  from  that  of 
the  abdominal  peritoneum  ;  and  if  the  rupture 
is  not  reduced  or  kept  up  by  a  truss,  it  will  pro- 
bably increase  in  size  without  any  remarkable 
alteration  of  tissue,  for  the  membrane  is  ex- 
tremely distensible,  and  will  accommodate 
itself  to  any  quantity  of  contents.  But,  if  the 
hernia  is  carefully  kept  up,  there  can  be  no 
doubt  that  the  sac  will  gradually  contract  and 
seem  to  rise  up  and  approach  the  opening 
through  which  it  originally  passed,  so  that, 
although  its  cavity  is  never  completely  oblite- 
rated, it  is  palpably  diminished  in  size,  and  in- 
capable of  receiving  and  retaining  the  same 
quantity  of  contents  it  originally  held.  Some- 
times in  old  and  neglected  herniae  the  sac 
seems  to  become  so  thin  that  the  peristaltic 
motion  of  the  intestines  within  it  has  been 
clearly  perceived  :  this  most  frequently  occurs 
in  umbilical  hernia,  and  is  one  of  the  reasons 
why  this  form  of  rupture  was  supposed  not  to 
have  been  enveloped  in  a  sac  at  all.  Again,  on 
the  contrary,  in  old  herniae  also,  and  particularly 
where  bandages  have  been  worn  to  support  or 
compress  the  tumour,  it  seems  to  become  very 
tnick,  strong,  and  tense,  and  is  said  to  have  been 
met  with  as  tough  and  as  thick  as  cartilage. 
But  in  the  great  majority  of  instances  these 
changes  are  rather  apparent  than  real,  and 
though^doubtloss  the  structure  of  the  sac  is  no 
longer  exactly  that  which  it  possessed  before 
protrusion,  the  alteration  is  not  so  great  as 

*  Scarpa  on  Hernia,  translated  byWishart,  p.  68. 
t  See  Louis,  Mem.  de  l'Acad.  Roy.  de  Chir. 
torn.  ii.  p.  486. 


some  writers  have  supposed.  It  was  the 
opinion  of  Scarpa  that  an  old  hernial  sac  is  in 
reality  but  slightly  if  at  all  thickened,  and  that 
the  apparent  thickening  is  caused  by  the  con- 
densation of  the  cellular  tissue  external  to  and 
around  it.  And  here  I  may  remark  that  diffe- 
rences of  opinion  as  to  the  altered  structure  of 
the  sac  may  have  arisen  from  a  difference  of 
accuracy  and  minuteness  in  examination,  either 
during  the  progress  of  an  operation  or  after 
death.  We  shall  find  hereafter  that  the  normal 
anatomy  of  the  parts  connected  with  hernia  is 
largely  indebted  to  the  knife  of  the  anatomist 
for  the  shapes  of  the  different  openings,  the 
division  and  enumeration  of  the  different  layers 
of  fascia,  and  many  other  points;  but  in  the 
morbid  anatomy  of  the  disease  the  same  patient 
investigation  and  the  same  accuracy  of  descrip- 
tion has  not  been  so  uniformly  observed,  and 
hence  our  knowledge  of  the  latter  part  of  the 
subject  as  compared  with  the  former  is  by  no 
means  so  defined  and  exact. 

Where  a  rupture  has  been  a  long  time  down, 
it  is  not  probable  that  the  intestine  shall  thus 
remain  in  an  abnormal  situation  without  occa- 
sionally suffering  from  inflammation,  and  hence 
adhesions  between  it  and  the  sac  are  by  no 
means  unfrequently  formed :  the  same  effect 
may  be  produced  by  accidental  violence,  or 
from  the  latter  cause  the  sac  may  be  ruptured 
and  its  contents  left  lying  under  the  usual 
coverings  independent  of  the  peritoneum. 
This  is  another  of  the  cases  in  which  a  hernia 
has  been  supposed  to  exist  without  the  invest- 
ment of  a  sac. 

The  peritoneal  aperture  leading  from  the 
cavity  of  the  abdomen  into  that  of  the  rupture 
is  narrow,  and  is  called  the  neck  of  the  sac  :  its 
dimensions  as  to  length,  however,  vary  with 
circumstances.  As  long  as  the  communication 
is  open  and  free  between  the  two  cavities,  all 
that  portion  of  peritoneum  which  is  placed 
between  them  and  corresponds  to  the  canal 
through  which  the  rupture  has  passed,  may  be 
termed  the  neck,  and  thus  in  inguinal  hernia 
may  be  an  inch,  and  in  crural  half  an  inch  in 
length.  But  when  the  protruded  parts  are 
strangulated,  the  little  circle  only  around  which 
the  compression  directly  operates  is  more  pro- 
perly entitled  to  the  appellation,  and  its  extent 
is  seldom  greater  than  two  lines.  When  the 
neck  of  the  sac  of  a  very  recent  hernia  is  viewed 
from  the  cavity  of  the  abdomen,  the  peritoneum 
in  its  vicinity  is  seen  thrown  into  slight  folds  or 
plaits,  which  appear  to  be  prolonged  downwards 
into  the  tumour;  but  on  slitting  open  the  neck, 
I  have  never  seen  this  appearance  within  it,  the 
membrane  there  being  smooth,  rather  whiter  and 
more  opaque,  and  evidently  thicker  and  more 
uryielding  than  elsewhere.  If  such  a  hernia 
in  the  living  subject  has  been  reduced  and  kept 
up  by  la  truss,  the  neck  gradually  contracts 
under  the  pressure,  and  iis  diameter  with  re- 
spect to  that  of  the  ring  tnrough  which  it  has 
passed  is  altered  to  a  degree  that  is  of  the 
greatest  importance  in  the  event  of  another  pro- 
trusion, for  it  will  be  shewn  hereafter  that  such 
a  diminution  of  size  greatly  predisposes  to  the 
occurrence  of  strangulation.    It  is  also  possible 

3  c  2 


740 


HERNIA. 


that  the  neck  shall  be  so  contracted  that  in  the 
new  occurrence  of  hernia  an  additional  portion 
of  peritoneum  may  be  detruded,  and  then  the 
sac  must  present  the  shape  of  an  hour-glass, 
narrow  in  the  centre  and  broad  at  either  end  : 
sometimes  two,  three,  or  more  of  these  succes- 
sive protrusions  take  place,  and  then  the  sac 
is  divided  into  so  many  sacculi  with  incomplete 
intercepts  or  partitions  between  them.  Or  one 
portion  of  peritoneum  may  be  forced  within 
another,  so  that  the  intestine  is  actually  in- 
cluded within  a  double  sac.  This  last  is  a 
curious  and  very  uncommon  occurrence.  On 
the  other  hand  the  neck  of  a  hernial  sac  may 
suffer  distension.  In  very  old  ruptures  that 
have  become  irreducible  or  from  any  other 
cause  been  long  down,  the  neck  of  the  sac 
sometimes  becomes  wonderfully  dilated,  and  the 
portion  of  intestine  immediately  passing  through 
it  scarcely  subjected  to  the  slightest  pressure. 

There  is  one  form  of  hernia,  the  chief 
peculiarity  of  which  lies  in  the  nature  of  its 
peritoneal  investment,  for, correctly  speaking,  it 
possesses  no  proper  sac.  It  is  the  hernia  con- 
genita,* a  species  of  rupture  which  occurs  in 
very  young  infants,  and  sometimes,  under 
peculiar  circumstances,  in  persons  of  a  more 
advanced  age  also. 

During  the  early  periods  of  foetal  existence 
the  testes  do  not  occupy  that  situation  which 
they  possess  in  after  life.  They  are  placed 
■within  the  abdomen,  above  the  pelvis,  which  at 
this  time  is  so  small  and  imperfectly  developed 
that  many  of  the  viscera  lodged  within  it  after- 
wards, seem  now  to  lie  within  the  belly.  They 
are  just  below  the  kidneys,  in  front  of  the  psoas 
muscle  at  each  side,  and  possess,  like  other 
viscera,  an  investiture  of  peritoneum,  which  is 
afterwards  to  be  the  tunica  vaginalis  testis. 
About  the  sixth  month,  or  perhaps  the  seventh 
or  even  later,  (for  it  observes  no  exact  rule  in 
this  respect,)  the  testis  begins  to  descend,  not 
gliding  behind  theperitoneum, but  preservingits 
own  investing  coat  until  it  comes  to  the  internal 
abdominal  ring,  where  it  pushes  a  process  of 
peritoneum  out  before  it,  just  as  an  intestine 
would  do  in  the  production  of  a  hernial  sac. 
This  is  afterwards  to  become  the  tunica  vaginalis 
scroti.  The  testicle  then  passes  on  through  the 
inguinal  canal,  through  the  external  ring,f  and 
finally  drops  into  the  scrotum.  After  some 
time  the  canal  of  communication  with  the  cavity 
of  the  abdomen  begins  to  contract  and  close, 
and  if  the  usual  process  goes  on  healthily  and 
without  interruption,  very  shortly  a  complete 
obliteration  takes  place,  and  the  testis  is  sepa- 
rated from  the  abdomen  perfectly  and  for  ever. 
The  time  at  which  this  is  accomplished  is  ex- 
tremely uncertain  :  sometimes  it  is  perfect  at 
birth  ;  in  other  cases  the  canal  is  more  or  less 
open,  and  then,  if  the  infant  cries  or  struggles, 
a  portion  of  the  contents  of  the  abdomen  is 
protruded  into  the  cavity  of  the  tunica  vaginalis, 

*  Hunter's  Animal  (Economy. 

+  Sec  some  observations  on  the  descent  of  the 
testicle  by  the  late  Professor  Todd,  of  Dublin,  in  the 
1st  vol.  Dublin  Hospital  Reports.  See  also  Hey's 
Observations  in  Surgery,  p.  226. 


and  the  hernia  congenita  is  formed.  If  any  part 
of  the  above-mentioned  process  is  interrupted 
or  postponed,  it  will  occasion  some  variety. 
Thus  the  tunica  vaginalis  may  not  exhibit  its 
usual  disposition  to  close  and  become  obliter- 
ated at  its  neck,  and  then  for  a  length  of  time 
the  patient  is  exposed  to  all  the  inconvenience 
and  hazard  of  the  descent  of  a  hernia:  sometimes 
the  testicle  does  not  come  down  until  a  much 
later  period,  a  circumstance  that  is  often  occa- 
sioned by  the  gland  contracting  adhesions  with 
some  adjacent  viscus  in  its  passage,  and  may  be 
attended  with  the  additional  inconvenience  of 
drawing  down  such  viscus  along  with  it.  The 
surgeon  should  also  be  aware  of  the  possibility 
of  the  protrusion  of  another  portion  of  perito- 
neum into  the  open  tunica  vaginalis,  and  thus  a 
mixed  case  may  arise  of  a  congenital  containing 
within  it  a  proper  sacculated  hernia. 

The  congenital  rupture,  then,  has  no  proper 
sac,  but  is  lodged  within  the  tunica  vaginalis  in 
close  apposition  with  the  testis  :  hence  many 
of  its  peculiarities  can  be  explained.  It  is 
obviously  the  only  kind  of  hernia  in  which  an 
adhesion  can  exist  between  the  testicle  and  the 
protruded  viscus,  and  it  is  also  evident  that  the 
testis  does  not  bear  the  same  relation  to  the 
protruded  viscus  in  this  that  it  does  in  cases  of 
ordinary  rupture.  Here  it  is  higher  up,  and 
seems  to  be  more  mixed  and  identified  with  the 
other  contents;  the  entire  tumour  is  more  even 
and  firm,  the  protruded  parts  are  less  easily 
felt  and  distinguished;  and  Hesselbach  states 
that  when  strangulation  is  present,  the  sac  is 
every  where  equally  tense,  and  the  testis  cannot 
be  felt  at  all.  In  very  young  infants  a  small 
quantity  of  fluid  is  often  present  along  with  the 
intestine  in  the  tunica  vaginalis :  it  disappears 
when  the  child  is  placed  in  the  recumbent  posi- 
tion, and  does  not  add  to  the  difficulty  or  im- 
portance of  the  case.  It  has  been  stated  that 
the  tunica  vaginalis  has  a  natural  tendency  to 
become  closed  at  its  neck,  and  therefore  is  it 
more  likely  to  thicken  and  diminish  in  capacity 
in  this  situation  so  as  to  form  a  band  round  the 
protruded  viscus.  Pott*  was  of  opinion  that 
congenital  hernia  was  more  subject  to  be  con- 
stricted at  the  neck  of  the  sac  than  any  other : 
Wilmer  stated  that  out  of  five  cases  of  congen- 
ital hernia  on  which  he  operated,  three  were 
strangulated  at  the  neck  of  the  sac;  and  Sandi- 
fort  and  others  maintained  the  same  doctrine. 
Scarpaf  thought  that  every  displaced  portion 
of  peritoneum  possessed  the  same  tendency  to 
contraction,  and  advanced  it  as  a  reason  why 
stricture  in  the  neck  of  a  hernial  sac  should  be 
more  frequent  in  all  kinds  of  hernia  than  is 
generally  supposed.  It  is  not  easy  to  place 
implicit  reliance  on  this  latter  opinion,  because 
the  neck  of  the  common  hernial  sac  when  once 
formed  is  never  again  completely  closed  ;  but 
with  respect  to  congenital  hernia  the  observa- 
tion appears  to  be  equally  correct  and  im- 
portant. 

Scarpa}  describes  a  form  of  hernia  which  may 

*  Pott,  op.  citat.  p.  184. 
t  Page  131. 

$  Op.  citat.  p.  205  et  seq. 


HERNIA. 


741 


under  certain  circumstances  of  imperfect  or  care- 
less examination  appear  to  be  devoid  of  a  proper 
sac,  formed  by  a  descent  of  the  peritoneum. 
This  occurs  at  the  right  groin,  is  always  large, 
and  is  formed  by  a  protrusion  of  the  ccecum 
with  the  appendix  vermiformis  and  the  begin- 
ning of  the  colon.  The  coscum  is  placed  in  the 
right  ileo-lumbar  region,  and  a  portion  of  it  does 
not  possess  a  peritoneal  covering,  but  lies  abso- 
lutely without  the  great  abdominal  membranous 
sac:  when  therefore  these  parts  are  protruded, 
a  portion  of  the  ccecum  and  the  beginning  of 
the  colon  will  be  found  included  and  contained 
in  the  hernial  sac,  while  another  portion  of  the 
same  intestines  will  be  necessarily  without  the 
sac,  and  lying  denuded  in  the  cellular  substance 
which  accompanies  the  descent  of  the  perito- 
neum in  the  hernia.    If  this  tumour  is  opened 
into  by  an  incision  carried  too  much  towards 
its  external  side,  the  ccecum  and  colon  will  be 
exposed  lying  outside  of  the  peritoneum,  and  ap- 
parently devoid  of  a  hernial  sac;  but  if  cut 
into  precisely  in  the  middle  or  a  little  towards 
the  inner  side,  under  the  cremasler  muscle  and 
the  subjacent  cellular  tissue,  the  true  hernial 
sac  will  be  found,  formed  of  the  peritoneum. 
Within  this  will  be  seen  "  the  greater  portion 
of  the  ccecum  with  the  appendix  vermiformis, 
and  likewise  the  membranous  folds  and  bridles 
which  seem  to  be  detached  from  the  hernial 
sac  to  be  inserted  into  these  intestines,  the 
smaller  portion  of  which  will  be  without  the 
sac,  in  the  same  manner  as  when  these  viscera 
occupied  the  ileo-lumbar  region."    This  form 
of  rupture  I  have  never  seen,  and  must  there- 
fore refer  the  reader  to  Scarpa's  work,  wherein 
he  will  find  the  peculiarity  most  satisfactorily 
explained. 

But  in  the  arrangement  of  herniae,  that  di- 
vision is  most  practically  interesting  which  has 
reference  to  the  condition  or  state  of  the  intes- 
tine or  other  protruded  viscus,  and  the  disease 
is  then  described  as  being  reducible,  or  irredu- 
cible, or  strangulated. 

1.  A  hernia  is  said  to  be  reducible  when  it 
either  retires  spontaneously  on  the  patient  as- 
suming the  recumbent  posture,  or  can  be  re- 
placed without  difficulty  to  the  operator  or 
future  inconvenience  to  the  patient  beyond  that 
resulting  from  the  employment  of  measures 
adapted  to  retain  it  within  the  cavity.  This 
condition  supposes  that  the  relation  (particu- 
larly as  to  size)  between  the  hernia  and  the 
aperture  through  which  it  had  escaped  has  not 
undergone  any  alteration. 

2.  It  is  irreducible  when  there  is  such  a 
change  in  the  structure,  situation,  or  other  con- 
dition of  the  protruded  viscus  as  to  render  it 
impossible  to  be  returned,  although  the  aper- 
ture through  which  it  passed  may  offer  no  im- 
pediment. There  is  another  case  in  which  a 
hernia  has  been  considered  irreducible,  namely, 
when  it  would  be  impolitic  or  unwise  to  attempt 
the  reduction,  supposing  it  to  be  perfectly 
practicable. 

3.  A  hernia  is  strangulated  when  the  relation 
as  to  size  between  the  protruded  viscus  and  the 
aperture  through  which  it  has  passed  is  so 
altered  as  not  only  to  prevent  reduction,  but 


to  cause  such  a  degree  of  compression  at 
the  aperture  as  will  interrupt  the  circulation 
through  the  escaped  viscus,  and  endanger  its 
vitality.  This  condition  has  been  supposed  to 
exist  in  two  different  forms,  strangulation  by 
inflammation  and  by  "  engouement,"*  or  as 
Scarpa  terms  them,  "  the  acute  and  chronic  ;"f 
but  this  division  only  has  reference  to  the 
severity  of  the  symptoms  aud  to  the  rapidity 
or  slowness  of  their  progress,  for  although  an 
intestine  may  be  in  a  state  of  obstruction  which 
will,  if  unrelieved,  proceed  to  strangulation,  yet 
the  latter  state  cannot  be  said  to  have  arrived 
until  the  return  of  the  venous  blood  from  it  is 
actually  impeded.  The  protruded  viscus  is 
then  in  a  situation  precisely  similar  to  that  of  a 
limb  round  which  a  cord  had  been  tied  with 
sufficient  tightness  to  interrupt  the  circulation 
and  threaten  to  induce  mortification. 

These  different  conditions  will  be  best  under- 
stood by  tracing  a  rupture  through  each  of  them 
in  succession. 

A  person  may  be  suspected  to  have  a  reduci- 
ble hernia  when,  after  the  application  of  some 
force  calculated  violently  to  compress  all  the 
viscera  of  the  abdomen,  an  indolent  tumour 
appears  proceeding  from  some  of  those  places 
where  the  walls  of  the  abdomen  are  Known  to 
be  weakest  and  least  resisting.  And  the  sus- 
picion is  increased  if  the  tumour  is  elastic,  if 
it  sounds  clearly  on  gentle  percussion,  and 
becomes  suddenly  puffed  up  and  swelled,  as  if 
by  air  blown  into  it,  when  the  patient  coughs, 
sneezes,  or  performs  any  of  those  actions  which 
forcibly  agitate  the  abdominal  parietes.  The 
reducible  hernia  becomes  smaller  or  .perhaps 
disappears  altogether  when  the  patient  lies 
down  :  it  appears  of  its  full  size  when  he  stands 
erect ;  if  neglected,  it  has  a  constant  tendency 
to  increase,  which  it  does  sometimes  by  de- 
grees, slowly  and  almost  imperceptibly,  but 
more  frequently  by  sudden  additions  to  its 
bulk,  which  are  formed  by  new  protrusions. 
In  this  form  of  the  disease  the  qualities  of  the 
viscus  engaged  within  the  sac,  as  to  form,  size, 
and  structure,  may  be  considered  as  unchanged  : 
within  the  abdomen,  however,  the  fold  of 
mesentery  which  supports  the  protruded  intes- 
tine is  constantly  more  elongated  than  it  natu- 
rally should  be,  and  likewise  thicker  and  more 
loaded  with  fat.  It  is  also  marked  with  dilated 
and  tortuous  veins. 

Although  thus  displaced,  the  viscus  is_  still 
capable  of  performing  its  part  in  the  function 
of  digestion,  and  as  long  as  the  contents  of  the 
bowel  pass  fairly  and  uninterruptedly  through 
it,  there  can  be  little  or  no  danger;  but  it  is 
not  difficult  to  conceive  how  a  gut  so  circum- 
stanced may  occasion  great  inconvenience. 
The  peristaltic  motion  must  be  more  or  less 
impaired  ;  the  passage  of  the  contents  may  be 
delayed,  and  hence  will  arise  nausea,  colicky 
pains,  eructations,  and  those  other  dyspeptic 
symptoms  from  which  even  the  most  favoured 
patients  do  not  escape.    These  irregularities 

*  Goursaud,  Mem.  del' Acad.  Roy.  de  Chir.  torn, 
ii.  p.  382. 

t  Op.  cit.  p.  290. 


742 


HERNIA. 


again  can  scarcely  exist  for  any  length  of  time 
without  producing  some  inflammation,  and 
thence  it  follows  that  it  is  rare  to  meet  with  an 
old  hernia  in  which  adhesions  have  not  formed 
either  between  the  intestine  and  the  sac,  or 
between  the  convolutions  of  the  protruded 
viscera,  circumstances  that  must  render  it  im- 
possible to  replace  the  hernia,  or  supposing  it 
replaced  by  force,  will  be  likely  to  occasion 
incarcerations  within  the  cavity  of  the  abdomen 
itself.  These  adhesions,  as  discovered  either 
during  operation,  or  by  dissection  after  death, 
are  of  different  degrees  of  closeness,  firmness, 
and  tenacity,  and  have  been  arranged  under 
three  classes,  the  gelatinous,  the  membranous, 
and  the  fleshy. 

"The  gelatinous  adhesion,  a  very  general 
consequence  of  the   adhesive  inflammation 
which  attacks  membranous   parts  placed  in 
mutual  contact,  is  only  formed  by  a  certain 
quantity  of  coagulable  lymph,  effused  from  the 
surface  of  the  inflamed  parts,  which  coagulating 
assumes  sometimes  the  appearance  of  a  vesi- 
cular reddish  substance  stained  with  blood, 
sometimes  of  threads  or  whitish  membranes 
easily  separable  from  the  parts  between  which 
they  are  interposed  and  which  they  unite  to- 
gether, without  any  abrasion  or  laceration  being 
produced  by  the  separation,  on  the  surface  of 
the  parts  agglutinated  together."*    This  kind 
of  adhesion  being  the  result  of  recent  inflam- 
mation can  rarely  be  met  with  in  operations 
performed  for  the  relief  of  strangulated  hernia, 
for  the  condition  of  a  viscus  so  engaged  is  that 
in  which  such  an  effusion  would  be  unlikely,  if 
not  impossible.    Its  vessels  are  loaded  and 
congested  with  venous  blood  :  there  is  effusion 
of  serum  to  a  greater  or  less  quantity,  as  is  seen 
in  every  instance  of  obstructed  venous  circu- 
lation ;  and  if  there  is  recent  lymph,  it  must  be 
owing  to  the  fortuitous  circumstance  of  the 
viscus  having  been  inflamed  immediately  before 
it  became  strangulated.    In  a  vast  number  of 
cases  operated  on,  I  have  seen  but  one  instance 
of  the  existence  of  this  soft  adhesion,  and  in  that 
the  hernia  was  not  strangulated  :  it  was  a  case 
(such  as  is  related  by  Pott)  of  inflammation 
affecting  the  intestines  generally,  in  which  those 
within  the  hernial  sac,  of  course,  participated. 

The  membranous  and  fleshy  adhesions  are 
the  results  of  former  attacks  of  inflammation, 
and  are  exactly  similar  to  those  attachments  so 
frequently  met  with  between  serous  surfaces  in 
other  situations.  When  the  opposed  surfaces 
lie  motionless  and  undisturbed,  their  connexion 
is  firm  and  fleshy,  and  hence  this  kind  of  adhe- 
sion is  seen  at  the  neck  of  the  sac,  between  the 
omentum  and  the  sac,  and  occasionally  between 
the  intestine  and  the  testicle  in  congenital 
hernia;  whilst  between  the  convolutions  of  the 
intestine  itself,  or  between  it  and  the  sac,  any 
union  that  exists  is  more  generally  loose  and 
membranous. 

Besides  adhesion,  there  are  many  other 
causes  that  may  render  a  hernia  irreducible, 
one  of  the  most  prominent  of  which  is  the 
patient's  neglect  in  leaving  the  hernia  down, 

*  Scarpa,  p.  180. 


and  the  alterations  in  shape  and  structure  that 
thence  ensue.  In  such  case,  the  parts  within 
the  tumour,  as  the  mesentery  and  omentum, 
have  room  to  increase,  whilst  at  the  mouth  of 
the  sac  they  remain  constricted  and  of  their 
natural  size,  though  condensed  and  solidified  in 
structure.  This  happens  particularly  with  the 
omentum,  which  becomes  hard,  very  dense,  and 
compact,  and  not  unfrequently  resembles  a 
fibrous  structure  covered  by  a  fine  smooth 
membrane,  and  then  there  is  within  the  sac  a 
tumour  actually  much  larger  than  the  aperture 
it  would  have  to  pass,  and  through  which  no 
force  could  be  capable  of  pushing  it. 

It  may  happen  that  the  part  of  the  omentum 
which  is  below  the  stricture  shall  remain  loose 
and  expanded,  and  enjoy  its  natural  structure, 
whilst  that  which  is  lodged  within  the  neck  of 
the  sac  is  compressed  and  hardened,  in  which 
case  the  hernia  will  probably  prove  irreducible. 

It  sometimes  happens  that  scirrhus  of  the 
intestine  renders  a  hernia  irreducible.  Such  a 
malignant  alteration  of  structure  is  by  no  means 
frequent  in  the  intestinal  tube — certainly  far 
less  so  than  in  the  omentum,  but  the  possibility 
of  the  occurrence  is  proved  by  a  case  under  my 
own  immediate  superintendence.  The  patient 
had  a  large  hernia  which  he  had  been  able 
occasionally  to  reduce,  but  which  was  usually 
left  down.  On  a  sudden  he  was  attacked  with 
symptoms  of  strangulation,  small  quick  pulse, 
tenderness  of  the  abdomen,  acute  pain  in  the 
tumour,  constipation,  general  low  fever  and 
fcecal  vomiting.  The  operation  was  performed, 
and  the  cause  of  the  symptoms  found  not  to 
have  been  in  the  situation  of  the  neck  of  the 
sac,  which  was  more  than  commonly  open  and 
free,  but  in  a  scirrhus  of  one  of  the  lesser 
intestines.* 

The  form  of  hernia  already  noticed  as  being 
apparently  devoid  of  a  sac  has  been  mentioned 
by  Pottf  as  one  peculiarly  difficult  of  reduc- 
tion. "  They  have  consisted  of  the  coecum  with 
its  appendicula  and  a  portion  of  the  colon. 
Nor,"  continues  this  distinguished  surgeon,"  will 
the  size,  disposition,  and  irregular  figure  of  this 
part  of  the  intestinal  canal  appear  upon  due 
consideration  a  very  improbable  cause  of  the 
difficulty  or  impossibility  of  reduction  by  the 
hand  only." 

The  last  circumstance  to  be  considered  as 
rendering  a  rupture  irreducible  is  the  absolute 
size  of  the  tumour  and  the  quantity  of  viscera 
it  contains.  It  is  amazing  to  what  extent  the 
contents  of  the  abdomen  may  be  protruded 
from  it,  and  the  patient  nevertheless  enjoy  a 
state  of  health  that  might  be  called  good,  so  far 
as  the  annoyance  of  such  a  tumour  could 
warrant  the  expression.  Every  surgeon  must 
have  heard  of  hernia?  in  which  all  the  loose 
intestines  were  protruded,  and  in  fact  every 
thing  that  could  with  any  degree  of  probability 
be  supposed  to  have  been  capable  of  being 
pushed  from  the  cavity  of  the  abdomen.  I 

*  The  preparation  of  this  interesting  case  is  in 
the  Museum  of  the  Medico-Chirurgical  School,  Park 
Street,  Dublin. 

f  Pott,  op.  cit.  p.  24. 


HERNIA. 


743 


have  seen  and  dissected  a  case  of  this  descrip- 
tion in  which  the  tumour  during  life  reached  to 
within  two  inches  of  the  knee,  and  obliged  the 
unfortunate  subject  of  it  (who  was  a  lamp- 
lighter) to  wear  a  petticoat  instead  of  breeches. 
Similar  instances  are  not  very  unfrequent,  and 
it  is  obvious  that  an  attempt  at  reduction  here 
would  be  injudicious  even  if  it  was  practicable. 
It  is  the  nature  of  all  hollow  structures  in  the 
body,  whether  cavities  or  vessels,  to  accommo- 
date their  size  and  capacity  to  the  quantity  of 
their  contents,  and  the  cavity  of  the  abdomen 
will,  under  such  circumstances,  become  so  con- 
tracted as  to  be  either  incapable  of  immediately 
receiving  the  protruded  viscera  again,  or  else 
the  sudden  distension  will  excite  peritoneal 
inflammation — an  evil  greater  than  the  existence 
of  the  hernia.  These  latter,  however,  cannot 
be  regarded  as  permanently  irreducible,  for 
Arnaud,  Le  Dran,  and  Hey  have  succeeded 
in  gradually  restoring  them  by  means  of  a 
bandage  shaped  like  a  bag,  which  being  laced 
in  front  admitted  of  being  tightened  still  as  the 
tumour  diminished. 

The  last  and  most  fearful  condition  of  a  rup- 
ture is  its  state  of  strangulation,  in  which  the 
protruded  viscus,  no  longer  capable  of  being 
returned  to  its  former  situation  within  the  ab- 
domen, no  longer  fit  for  the  performance  of  its 
functions,  is  banded  and  bound  down  at  its 
neck  in  such  wise  as  to  interrupt  and  impair 
the  circulation  through  it.  In  order  properly 
to  understand  this  part  of  the  subject,  it  will  be 
necessary  to  consider  it  under  three  heads: — 
1.  the  causes  that  seem  to  produce  the  stran- 
gulation ;  2.  its  effect  on  the  structures  within 
the  hernial  sac ;  3.  its  effect  on  the  viscera 
within  the  cavity  of  the  abdomen. 

1.  Of  the  three  natural  apertures  at  which 
abdominal  hernise  commonly  occur,  one,  the 
umbilicus,  is  unquestionably  seated  within 
tendon,  and  so  circumstanced  that  any  con- 
traction of  any  muscle  connected  with  it,  whe- 
ther spasmodic  or  permanent,  must  rather  ex- 
pand the  opening  than  contract  it.  Another, 
the  crural  ring  or  canal,  is  composed  of  tendon 
and  of  bone,  and  so  constructed  that  although 
certain  positions  of  thp  trunk  or  inferior  extre- 
mity might  possibly  diminish  its  size,  no  mus- 
cular action  can  exert  any  influence  over  it. 
The  third,  the  inguinal  canal,  is  of  greater  length 
and  more  complicated  in  its  construction,  and 
it  is  a  question  whether  the  same  pathological 
condition  can  be  predicated  of  it,  or  whether 
strangulation  does  not  here  occasionally  occur 
in  consequence  of  muscular  action  alone.*  Sir 
A.  Cooper  seems  to  acknowledge  the  possibility 
of  a  spasmodic  stricture  at  the  internal  ring,  the 
strangulation  then  being  effected  by  a  com- 
pression exercised  by  the  inferior  edge  of  the 
internal  oblique  and  transversalis  muscles.-f 
Guthrie  speaks  of  hernia?  being  frequently 
strangulated  by  passing  between  the  fibres  of 
the  internal  oblique,  which  are  separated  at  the 
inferior  and  external  border  of  the  muscle  above 


the  origin  of  the  cremaster.*  Scarpa  says  that 
"  towards  the  side,  at  about  eight  lines  distance 
from  the  apex  of  the  ring,  the  lower  muscular 
fibres  of  the  internal  oblique  muscle  separate 
from  each  other  to  allow  the  spermatic  cord  to 
pass  between  them:"f  and  again,  "  the  small 
sac  or  rudiment  of  the  hernia,  not  unlike  a 
thimble,  when  it  makes  its  first  appearance 
under  the  fleshy  margin  of  the  transverse,  rests 
immediately  on  the  anterior  surface  of  the 
spermatic  cord  ;  it  then  extends  and  passes  in 
the  middle  of  the  separation  formed  by  the 
divarication  of  the  inferior  fleshy  fibres  of  the 
internal  oblique  and  of  the  principal  origin  of 
the  cremaster  muscle."]:  It  must,  however,  be 
conceded  that  Scarpa  did  not  attribute  the 
strangulation  of  any  form  of  inguinal  hernia  to 
a  contraction  of  these  muscular  fibres.  Now, 
although  it  is  almost  presumptuous  to  differ 
from  authorities  of  so  high  a  class,  yet  I  cannot 
agree  either  with  the  opinion  that  hernise  are 
liable  to  a  spasmodic  constriction,  or  with  the 
descriptive  anatomy  on  which  such  an  opinion 
might  be  founded. 

In  about  one  subject  out  of  every  three  or 
four  there  certainly  is  a  slight  divarication  or 
separation  of  fibres  of  the  external  oblique 
muscle,  or  rather  there  is  a  cellular  connexion 
between  the  origin  of  the  cremaster  muscle  and 
the  inferior  fibres  of  the  oblique,  which  is  easily 
separable  by  the  knife;  but  the  question  is, 
does  the  spermatic  cord  in  the  natural  condition, 
or  the  hernia  in  its  course  to  the  external  ring, 
pass  through  or  between  these  fibres  ?  I  believe 
they  do  not.  I  have  dissected  numerous  cases 
of  hernia  without  observing  such  a  disposition 
of  parts,  and  I  think  that  if  either  the  spermatic 
cord  or  the  hernia  took  such  a  course,  the  pro- 
trusion must  then  come  to  lie  in  front  of  the 
cremaster  muscle — a  position  that  has  not  been 
hitherto  observed.  When  a  hernia  is  found  at 
the  groin,  the  tendon  of  the  external  oblique  is 
somewhat  stretched  and  arched  forwards  above 
Poupart's  ligament  in  front  of  the  inguinal 
canal  :  the  fascia  transversalis  maybe  stretched 
also,  and  the  epigastric  artery  pulled  out  of  its 
place  and  made  to  approach  the  linea  alba; 
but  the  muscles  arising  from  Poupart's  liga- 
ment, the  internal  oblique  and  transversalis,  re- 
main unchanged,  and  if  ever  strangulation  is 
effected  through  their  operation  it  is  in  the 
manner  suggested  by  Sir  A.  Cooper.  But  it 
is  more  simple  and  perhaps  more  scientific  to 
place  muscular  contraction  out  of  the  question 
altogether.  The  phenomena  of  strangulation 
exhibit  nothing  like  the  irregularities  of  spasm: 
there  is  no  sudden  exacerbation,  no  succeeding 
relaxation — no  alternation  of  suffering  and  re- 
lief, no  assuagement  of  symptom  from  medi- 
cines decidedly  antispasmodic;  I  he  disease  once 
established  goes  on  with  an  uninterrupted  and 
certain  progression  that  will  not  admit  of  expla- 
nation by  a  cause  so  irregular  as  spasm. 

But  it  is  unnecessary  to  resort  to  an  expla- 
nation which  might  prove  so  practically  dan- 


*  See  the  anatomy  of  inguinal  and  femoral  hernia 
in  a  future  part  of  this  article, 
f  Cooper  on  Hernia,  p.  21 . 


*  Guthrie. 

t  Scarpa,  op.  cit.  p.  27. 
t  Ibid,  p.  50. 


744 


HERNIA. 


gerous,  because  the  existence  of  strangulation 
with  all  its  fearful  sequelae  may  be  proved,  in 
situations  and  under  circumstances  where  the 
influence  of  spasm  or  of  muscular  action  is  ob- 
viously impossible.  Thus  intestines  have  been 
found  strangulated  within  the  cavity  of  the  ab- 
domen itself,  as  when  a  fold  of  intestine  has 
passed  through  an  accidental  opening  in  the 
mesentery  or  the  omentum,  or  when  artificial 
bands  or  nooses  have  been  formed  by  lymph, 
the  products  of  former  inflammation.  Scarpa 
relates  a  very  interesting  case  in  which  he 
found  that  the  appendix  vermiformis  surrounded 
in  the  manner  of  a  ring  and  strangulated  a  long 
loop  of  the  ileum  just  before  its  insertion  into 
the  colon. 

If  it  be  conceded  that  the  natural  openings 
at  whicli  abdominal  herniae  occur  are  composed 
either  of  tendon  or  of  tendon  and  of  bone,  and 
therefore  are  not  subject  to  accidental  variations 
of  size  from  irregular  muscular  action,  it  would 
seem  on  a  prima  facie  view  that  wherever  any 
substance  had  passed  out  it  ought  to  be  able 
to  return,  provided  an  equal  degree  of  force  is 
employed  with  that  which  originally  caused 
the  displacement.    And  this  actually  does  take 
place,  for  the  hernia  returns  spontaneously  or 
is  easily  reduced  as  long  as  the  original  propor- 
tion between  the  size  of  the  protruded  part  and 
that  of  the  aperture  remains  unaltered.  Again, 
as  long  as  this  relation  is  maintained,  the  cir- 
culation through  and  from  the  protruded  viscus 
will  continue  equable  and  healthy,  but  an  in- 
testine from  its  structure  and  its  functions  is 
extremely  liable  to  a  change  of  size,  and  when 
that  happens,  the  proportion  no  longer  exists, 
and  the  hernia  begins  to  become  incarcerated. 
If  not  relieved,  the  protruded  viscus  continues 
to  swell,  and  is  thus  made  to  form  an  acute 
angle  at  the  spot  where  it  escaped,  which 
tightens  the  ring  of  intestine  immediately  at 
the  neck  of  the  sac  :  the  return  of  the  venous 
blood  is  thus  prevented ;  the  swelling  then 
increases  until  not  even  gas  can  pass  through, 
and  then  strangulation  is  complete.    In  this 
way  a  number  of  circumstances  connected  with 
hernia  can  be  explained.    If  the  ring  is  small, 
a  very  trifling  change  of  size  in  the  protruded 
part  will  be  sufficient  to  cause  strangulation  : 
hence  crural  hernia  is  more  liable  than  inguinal, 
and  very  recent  ruptures  in  which  the  ring  is  of 
its  natural  size  than  those  of  long  standing,  in 
whicli  that   aperture  is   probably  enlarged. 
Persons  who  are  formed  with  large  rings,  and 
thus  possess  an  hereditary  disposition  to  hernia, 
are  less  liable  to  strangulation  :  this  may  ex- 
plain Pott's  remark  that  "  if  the  hernia  be  of 
the  intestinal  kind  merely,  and  the  portion  of 
the  gut  be  small,  the  risk  is  the  greater,  stran- 
gulation being  more  likely  to  happen  in  this 
case  ;"  for  assuredly  if  the  ring  is  so  small  as  to 
permit  only  the  escape  of  a  knuckle  of  intestine, 
a  very  trifling  change  in  the  latter  will  be  suffi- 
cient to  establish    a  disproportion  between 
them.    Again,  if  a  hernia  has  come  down,  and 
been  reduced,  and  kept  up  until  the  neck  of 
the  sac  has  been  diminished  in  size,  and  if 
afterwards  a  protrusion   takes  place,  a  very 
trifling  alteration  in  this  latter  will  render  it 


incapable  of  return,  and  explain  why  such  her- 
niae are  so  frequently  strangulated  at  the  neck 
of  the  sac.    Hence  it  appears  that  a  straitness 
or  tightness  at  one  of  the  rings  may  be  a  predis- 
posing cause  of  strangulation,  that  is,  may  be 
a  reason  why  one  hernia  should  become  sooner 
strangulated  than  another,  but  the  immediate 
or  efficient  cause  is  a  change  in  the  condition 
of  the  viscus  itself.    Thus  when  a  loop  of  in- 
testine is  gangrened,  and  its  contents  have 
escaped  totally  or  partially  into  the  sac,  the 
hernia  often  returns  spontaneously,  the  parts  in 
the  immediate  neighbourhood  of  the  ring  re- 
maining unaltered.    Also  if  such  a  hernia  is 
the  subject  of  operation,  there  is  no  necessity 
for  dilating  the  seat  of  the  stricture  :  indeed 
Louis  forbids  the  practice  lest  some  essential 
point  of  adhesion  should  be  destroyed.  "Di- 
latation," says  he,  "  is  only  recommended  in 
order  to  facilitate  the  reduction  of  the  strictured 
parts.    In  the  gangrened  intestine  there  is  no 
reduction  to  make,  and  there  is  no  longer 
strangulation,  the  opening   in  the  intestines 
having  removed  the  disproportion  that  had 
existed  between  the  diameter  of  the  ring  and 
the  volume  which  the  parts  had  acquired;  and 
the  free  passage  of  the  excrement  which  the 
sphacelus  has  permitted  removes  every  symptom 
that  depends  on  the  strangulation."*    In  like 
manner  may  be  understood  why  omental  her- 
niae are  less  liable  to  become  strangulated,  be- 
cause this  structure  is  not  subject  to  any  sud- 
den change  of  shape  or  increase  of  volume  : 
when  it  does  occur,  the  progress  of  the  disease 
is  more  slow,  and  the  symptoms  are  said  to  be 
less  severe. 

The  division  of  herniae  into  the  incarcerated 
and  strangulated,  or  into  the  acute  and  chronic 
forms  of  strangulation,  however  practically 
valuable  if  it  inculcates  a  different  mode  of 
treatment  for  these  affections,  is  yet  pathologi- 
cally incorrect  if  it  supposes  any  analogy  be- 
tween them  and  the  acute  and  chronic  species 
of  inflammation.  An  incarcerated  hernia  is 
not  strangulated  ;  it  is  really  in  a  condition  re- 
sembling irreducibility.  I  have  before  stated 
that  in  large  and  old  herniae  the  neck  of  the  sac 
generally  becomes  enlarged,  and  of  course  such 
a  change  of  dimensions  in  the  protruded  viscera 
as  is  necessary  to  cause  their  strangulation  will 
be  proportionally  less  likely  to  occur.  But 
hard  and  unwholesome  and  indigestible  sub- 
stances may  gain  admission  into  some  of  them 
and  lodge  there,  for  it  must  be  recollected  that 
the  process  of  digestion  cannot  be  very  favora- 
bly carried  on  in  intestines  thus  protruded, 
placed  in  positions  that  will  render  it  necessary 
that  their  contents  must  ascend  against  the  in- 
fluence of  their  own  gravity,  and  deprived  of 
the  salutary  pressure  exercised  by  the  walls  of 
the  abdomen  on  the  viscera  within  it.  If  such 
a  lodgment  is  formed,  it  will  be  the  cause  of 
future  accumulation,  and  may  occasion  a  deter- 
mination of  blood  to  the  part  or  even  inflam- 
mation within  it,  thus  gradually  increasing  its 
volume  and  leading  it  to  a  state  that  must  end 
in  strangulation.    Undoubtedly,  if  the  dura- 

*  Mem.  de  l'Acad.  Roy.  de  Chir.  torn.  viii.  p.  45. 


HERNIA. 


745 


tion  of  such  a  case  is  reckoned  from  the  first 
occurrence  of  symptoms,  which  at  that  period 
are  only  those  of  indigestion,  it  will  be  an  ex- 
ample of  a  very  chronic  case  of  strangulated 
hernia ;  but  these  two  stages  of  the  disease 
ought  to  be  distinguished,  for  the  treatment 
that  would  be  judicious  in  the  one  might  be 
injurious  or  destructive  in  the  other.  The  in- 
carceration of  a  hernia  does  not,  moreover,  ne- 
cessarily involve  its  eventual  strangulation,  and 
this  constitutes  a  vast  difficulty  in  the  case,  for 
on  the  one  hand  few  surgeons  will  advise  an 
operation  until  there  is  an  obvious  and  decided 
necessity  for  it,  and  on  the  other  it  is  quite 
possible  in  a  case  of  this  description  that  the 
symptoms  shall  never  be  urgent,  and  yet  the 
intestine  be  found  in  a  state  of  actual  sphace 
lus.  I  have  seen  a  patient  operated  on  in 
whom  the  hernia  had  been  down  and  the 
bowels  constipated  for  eighteen  days.  The 
intestine  was  completely  mortified. 

That  strangulation  which  is  most  rapidly 
formed  is  the  most  severe  in  its  symptoms  and 
the  most  dangerous  in  its  consequences,  but 
between  these  extremes  there  is  every  possible 
degree  of  intensity.  A  hernia  has  been  gan- 
grened in  eight  hours  after  protrusion.  Mr. 
Pott  frequently  mentions  a  single  day  as  caus- 
ing a  most  important  difference  in  the  case, 
and  1  have  found  an  intestine  sphacelated  on 
the  day  following  the  first  occurrence  of  the  dis- 
ease ;  however,  in  general  the  case  is  not  so 
quickly  decided,  although  every  moment  of  its 
duration  is  pregnant  with  danger.  The  change 
that  is  effected  in  the  strangulated  viscus  next 
demands  attention.  Its  altered  condition  has 
been  always  spoken  of  under  the  name  of  in- 
flammation,* not  from  want  of  a  perfect  and 
accurate  knowledge  of  its  pathology,  but  pro- 
bably from  the  term  appearing  convenient  and 
being  hastily  adopted  by  one  writer  from  ano- 
ther. Yet  as  it  is  not  inflammation,  the  name 
is  incorrect,  and  perhaps  it  has  been  injurious 
in  leading  practitioners  to  attempt  a  mitigation 
of  the  inflammation  in  the  tumour,  instead  of 
the  more  obvious  indication,  a  diminution  of 
its  size.  The  volume  of  a  strangulated  intes- 
tine is  always  increased.  In  small  hernias 
(which  in  this  respect  can  be  more  accurately 
examined)  the  intestine,  on  the  sac  being  divi- 
ded, starts  up  and  swells  out  as  if  relieved  from 
a  compressive  force.  It  always  contains  air, 
and  if  cut  into,  a  small  portion  of  dark-coloured 
serum  will  generally  escape.  Its  colour,  which 
is  manifestly  occasioned  by  an  accumulation  of 
venous  blood,  is  at  first  of  a  reddish  tint  of 
purple,  soon  however  changing  to  a  coffee 

'  *  "The  inflammation  that  takes  place  in  stran- 
gulated hernia  is  different  from  almost  every  other 
species  :  in  most  cases  it  is  produced  by  an  unusual 
quantity  of  blood  sent  by  the  arteries  of  the  part, 
which  become  enlarged  ;  but  still  the  blood  returns 
freely  to  the  heart,  and  the  colour  of  the  inflamed 
part  is  that  of  arterial  blood  ;  whilst  in  hernia  the 
inflammation  is  caused  by  a  stop  being  put  to  the 
return  of  the  blood  through  the  veins,  which  pro- 
duces a  great  accumulation  of  this  fluid,  and  a 
change  ot  its  colour  from  the  arterial  to  the  venous 
hue.'     Cooper  on  Hernia,  p.  20. 


brown,  and  there  is  always  more  or  less  of 
serum  within  the  sac,  as  in  every  other  case  of 
venous  congestion.  If  unrelieved,  dark  and 
fibrous  spots  appear  which  are  truly  specks  of 
mortification ;  they  very  soon  separate  and 
allow  a  discharge  into  the  sac  of  a  quantity  of 
putrid  fjeces  and  horribly  fetid  gas.  This 
done,  the  intestine  either  remains  collapsed 
within  the  sac,  or  retires  spontaneously  into  the 
abdomen. 

In  the  meantime  the  parts  covering  the 
hernia  become  inflamed;  in  the  first  instance 
probably  from  sympathy  with  the  deeper  struc- 
tures, afterwards  obviously  as  an  effort  of  nature 
to  get  rid  of  the  putrid  and  sphacelated  matter 
underneath.  In  the  early  stages  the  local  symp- 
toms are  seldom  very  severe:  the  tumour  is 
scarcely  painful,  and  will  permit  reiterated  at- 
tempts at  the  reduction  of  the  hernia,  and  en- 
dure considerable  pressure,  whilst  the  abdomen 
may  not  be  touched  without  intense  suffering. 
In  a  little  time,  however,  it  becomes  tense  and 
tender  to  the  touch,  red,  oedematous,  and  pitting 
under  the  finger,  which  leaves  a  white  impres- 
sion for  a  moment  after  it  has  been  withdrawn. 
In  fact,  it  is  erysipelatous  inflammation  attack- 
ing the  coverings  of  the  hernia,  and  its  approach 
is  often  accelerated  by  handling  the  tumour  or 
by  repeated  injudicious  attempts  to  reduce  it. 
This  (if  the  patient  lives  sufficiently  long) 
always  terminates  by  the  formation  of  one  or  more 
sloughs,  on  the  separation  of  which  the  putrid 
coverings  are  thrown  off,  and  the  contents  of 
the  bowels  being  evacuated,  the  patient's  life 
may  be  saved,  but  with  the  inconvenience  and 
danger  of  an  artificial  anus  at  the  groin.    It  is 
seldom  that  the  efforts  of  nature  are  thus  ca- 
pable of  procuring  relief,  the  contents  of  the 
rupture  being  generally  sphacelated,  and  incu- 
rable mischief  effected  within  the  abdomen 
long  before  its  external  coverings  shew  anv  dis- 
position to  burst  spontaneously.    I  think  the 
condition  of  the  sac  has  some  influence  on  this 
external  inflammation.    In  all  cases  it  under- 
goes a  less  injurious  alteration  of  structure  than 
the  intestine  contained  within  it,  and  is  often 
found  comparatively  sound  while  the  latter  is 
in  a  state  approaching  to  sphacelus.  The  supe- 
riority of  its  vascular  organization,  its  containing 
a  greater  quantity  of  blood,  and  moreover  the 
volume  of  air  always  contained  within  the 
bowel,  will  explain  this  pathological  difference; 
but  the  sac  itself  sometimes  suffers  from  con- 
gestion to  a  greater  or  less  extent,  and  this,  of 
course,  in  proportion  to  the  degree  of  con- 
striction fixed  upon  its  neck.    An  old  hernial 
sac,  the  neck  of  which  is  thickened  and  ac- 
customed to  its  new  position,  and  which  is 
itself  probably  one  of  the  chief  causes  of  the 
stricture,  will  be  less  likely  to  suffer  from  an 
interrupted  circulation  than  a  recent  protrusion 
just  forced  out  through  a  narrow  undilated 
ring.    It  is  in  this  latter  case  that  the  external 
structures  ought  to  be  the  soonest  engaged,  and 
it  has  been  in  recent  and  acute  cases  of  hernia 
that  I  have  seen  the  earliest  examples  of  super- 
ficial inflammation. 

3.  Such,  during  the  progress  of  a  hernia,  is 
the  condition  of  the  parts  more  locally  engaged; 


746 


HERNIA. 


but  a  far  more  serious  because  a  more  fatal 
process  is  going  forward  within  the  abdomen. 
It  must  be  recollected  that  a  gangrene  of  the 
intestine  when  out  of  the  abdominal  cavity  is 
not  necessarily  fatal ;  that  the  gut  may  die  and 
putrefy,  and  be  thrown  off  by  the  results  of 
external  inflammation  and  sloughing,  and  yet 
the  patient  live  for  many  years  with  an  artificial 
anus,  or  even  have  the  natural  passage  per  anurn 
restored  again.  Numberless  cases  of  artificial 
anus  have  thus  occurred,  not  one  of  which 
could  have  been  saved  if  the  sloughing  of  the 
intestine  was  inevitably  mortal.  But  soon 
after  the  strangulation  is  effected,  either  from 
the  pressure  on  the  viscus,  which  may  be  sup- 
posed to  have  a  material  influence,  or  from  the 
mechanical  obstruction  to  the  passage  of  the 
feces,  inflammation  is  established  within  the 
cavity,  commencing  probably  at  the  strictured 
spot,  and  spreading  thence  with  great  rapidity. 
The  part  of  the  peritoneum  most  engaged  is 
that  which  covers  the  line  of  intestine  inter- 
posed between  the  stricture  and  the  stomach ; 
the  least,  that  which  invests  the  walls  of  the 
cavity.  This  inflammation  may  be  in  part 
salutary,  for  it  occasionally  causes  an  adhesion 
of  the  intestine  at  the  neighbourhood  of  the 
ring  so  firm  that  it  cannot  be  removed  there- 
from, and  thus  provides  for  the  occurrence  of 
an  artificial  anus  subsequently  without  the 
danger  of  any  internal  effusion  ;  but  unless  the 
stricture  is  relieved  at  this  time,  and  a  check 
thus  given  to  the  progress  of  the  disease,  the 
intestines  become  matted  with  lymph,  effusions 
are  poured  out  of  a  similar  nature  to  those  that 
occur  in  other  forms  of  peritonitis,  and  the 
patient  dies — not  of  the  gangrene  of  the  pro- 
truded intestine,  but  of  the  peritoneal  inflam- 
mation within. 

On  opening  the  body  of  a  person  who  has 
thus  died,  the  intestines  above  the  stricture  are 
found  inflamed,  of  a  red  or  pink  colour,  greatly 
distended  with  flatus  and  perhaps  with  fecal 
matters  ;  below  the  stricture  they  are  inflamed 
also,  but  remarkably  diminished  in  size.  There 
is  always  an  effusion  of  lymph  to  a  greater  or 
less  extent  glueing  the  convolutions  of  the 
bowels  together,  and  there  is  often  on  the  sur- 
face of  the  peritoneum  not  covered  with  lymph, 
a  dark  appearance  as  if  blood  was  ecchymosed 
beneath  it.  Effusions  are  also  constantly  met 
with,  sometimes  apparently  of  pure  pus, 
diffused,  particularly  throughout  the  spaces 
formed  by  the  apposition  of  the  convoluted 
intestines,  sometimes  more  abundant,  and  con- 
sisting of  serum  mixed  with  lymph  in  loose 
and  floating  flakes ;  and  occasionally  a  more 
gelatinous  substance  is  observed  very  much  re- 
sembling the  jelly-like  material  that  surrounds 
frog-spawn  in  stagnant  ponds.  I  have  never 
met  the  existence  of  gangrene  within  the  ab- 
domen in  any  case  of  death  from  strangulated 
hernia. 

The  line  of  intestine,  then,  within  the  ab- 
domen, and  the  loop  within  the  sac,  are  diffe- 
rently circumstanced.  Above  the  stricture 
there  is  active  inflammation  exactly  such  as 
might  occur  idiopathically,  presenting  the  same 
morbid  appearances,  and  accompanied  by  a 


similar  train  of  symptoms :  below,  there  is  a 
state  of  venous  congestion  in  which  the  vessels 
endeavour  to  relieve  themselves  by  pouring  out 
a  serous  effusion,  and  in  which  gangrene  super- 
venes with  a  rapidity  proportioned  to  the  tight- 
ness of  the  constriction.  Between  these,  and 
immediately  under  the  stricture,  it  is  white, 
pale,  and  bloodless  all  round  for  the  spaee  of 
two  or  three  lines,  and  appears  to  be  diminished 
in  size  more  than  it  really  is  on  account  of  the 
great  enlargement  immediately  above  and  below. 
The  condition  of  this  strictured  ring  of  intestine 
is  of  the  utmost  importance  in  the  progress  of 
the  case,  for  it  is  not  uncommon  for  it  to  ulce- 
rate or  to  slough  under  the  influence  of  the 
continued  pressure.  I  have  seen  an  operation 
admirably  performed,  and  the  intestine  returned 
under  apparently  favourable  circumstances, 
yet  the  patient  sink  and  die  in  the  course  of  a 
few  hours :  a  small  hole  existed  in  the  con- 
stricted spot,  through  which  fecal  matter  had 
escaped  and  become  diffused  within  the  cavity. 
In  another  instance,  from  the  anxiety  of  an 
operator  to  inspect  the  condition  of  this  spot 
previous  to  the  return  of  a  hernia,  the  intestine 
in  the  act  of  being  drawn  out  tore  almost  as 
easily  as  a  wetted  rag. 

It  will  not  be  difficult  to  connect  the  symp- 
toms of  this  disease  with  the  morbid  alterations 
just  described.  When  a  hernia  is  about  to 
become  strangulated,  the  earliest  symptom  is 
in  general  pain,  at  first  referred  to  the  seat  of 
the  stricture,  but  soon  becoming  diffused  over 
the  abdomen,  when  the  chief  suffering  is  often 
seated  in  the  region  of  the  navel.  The  belly 
then  becomes  hard  and  tense,  at  first  rather 
contracted,  but  subsequently  swollen  and  tym- 
panitic :  it  is  exquisitely  tender  to  the  touch, 
cannot  endure  the  slightest  pressure,  and  in 
some  cases  even  the  contact  of  the  bed-clothes 
is  intolerable.  The  patient  lies  in  bed  with 
his  legs  drawn  up,  and  if  possible  his  shoulders 
bent  forward  on  the  trunk  ;  he  cannot  without 
excessive  torture  endeavour  to  move  himself  in 
any  direction,  and  a  moment  in  the  sitting  pos- 
ture is  not  to  be  endured.  Of  course  when 
the  whole  canal  of  the  intestine  is  constricted, 
there  must  be  constipation  of  the  bowels  ;  yet 
cases  have  been  mentioned  in  which,  though 
all  the  other  symptoms  of  strangulated  hernia 
were  present,  the  discharges  from  the  bowels 
have  not  ceased, — a  circumstance  that  has  been 
explained  by  the  supposition  that  only  a  por- 
tion of  the  circumference  of  the  intestine  was 
engaged.  I  believe,  however,  that  most  of 
these  cases  were  delusive,  and  that  when  the 
alvine  discharges  have  continued  to  a  very  late 
period,  the  case  was  one  of  incarceration  in 
which  peritoneal  inflammation  may  not  be 
established  for  a  long  time  or  perhaps  at  all ; 
or  else  the  practitioner  was  deceived  by  some 
of  those  discharges  from  the  line  of  intestine 
below  the  stricture  which  are  so  frequently 
brought  away  by  the  administration  of  enemata. 
The  explanation  of  the  symptom  is  too  mecha- 
nical, particularly  when  it  is  recollected  that 
idiopathic  inflammation  of  the  peritoneum  will 
generally  (although  not  always)  produce  the 
same  effect,  and  that  it  is  as  regular,  as  constant, 


HERNIA. 


747 


and  as  complete  in  omental  as  in  intestinal 
ruptures.    At  a  very  early  period  of  the  case 
the  stomach  becomes  engaged,  and  there  is 
vomiting,  at  first  in  large  quantity  until  the 
contents  of  the  stomach  are  evacuated ;  it  is 
then  less,  dark-coloured,  and  excessively  bitter; 
and  finally  a  substance  is  discharged  having  the 
appearance  and  fetor  of  the  feculent  contents  of 
the  great  intestines.    Considering  the  structure 
and  functions  of  the  valve  of  the  ileum,  it  ap- 
pears curious  how  an  anti-peristaltic  motion 
could  be  so  completely  established  as  to  permit 
of  actual  fcecal  vomiting,  and  the  fact  (if  it  is  a 
fact)  cannot  be  explained  except  by  supposing 
the  action  of  all  the  constituent  structures  of 
the  intestine  so  deranged  that  the  influence  of 
the  valve  is  altogether  lost.    But  it  is  more 
than  doubtful  whether  this  material  is  really 
feculent,  although  it  is  difficult  from  its  sensible 
qualities  to  consider  it  in  any  other  point  of 
view;  for  I  have  frequently  seen  this  vomiting 
in  cases  where  the  hernia  were  formed  of  loops 
of  the  lesser  intestines,  and  therefore  when  the 
contents  of  those  beyond  the  iliac  valve  could 
not  have  been  thrown  off ;  and  in  every  case  it 
is  difficult  from  the  examination  of  the  dis- 
charge to  determine  its  nature  with  accuracy. 
After  the  stomach  has  been  emptied  of  its 
natural  contents,  the  act  of  vomiting  assumes  a 
very  peculiar  character  :  strictly  speaking,  it  is 
not  vomiting  or  retching,  nor  is  it  hiccup,  but 
a  slight  convulsive  effort  like  a  gulp,  which 
brings  up  without  much  effort  the  quantity  of 
a  single  mouthful  at  a  time.    The  forehead  is 
now  bedewed  with  a  cold  and  clammy  sweat; 
the  countenance  presents  a  remarkable  expres- 
sion of  agony  and  anxiety  ;  and  the  pulse  is 
small,  quick,  hard,  and  vibrating,  as  is  the  case 
in  all  internal  inflammations  of  vital  parts. 

After  some  further  time  (and  the  period  is 
very  variable)  the  characters  of  the  disease 
undergo  a  fearful  alteration.  Mortification 
attacks  the  incarcerated  viscus,  and  in  most 
instances  seems  to  bring  the  result  of  the  case 
to  a  very  speedy  issue.  The  tumour  now  loses 
its  tense  feel,  and  becomes  soft,  flabby,  and 
perhaps  emphysematous  :  in  some  instances  it 
retires  altogether.  The  belly  also  may  become 
soft,  and  in  general  there  is  a  discharge  per 
anum  of  dark-coloured  and  abominably  offen- 
sive fseces.  This  evacuation  leads  the  patient 
into  the  encouragement  of  false  hopes,  for  he 
may  have  seen  his  surgeon  endeavouring  to 
procure  stools  during  the  progress  of  the  case, 
and  combining  this  circumstance  with  the 
removal  of  the  pain  and  the  comparative  ease 
he  so  suddenly  experiences,  he  fancies  so  favour- 
able a  change  to  be  the  harbinger  of  recovery. 
But  the  delusion  lasts  not  long.  The  pulse 
becomes  low,  weak,  and  faltering :  often  it 
intermits  irregularly.  The  countenance  is 
sunken,  and  assumes  an  appearance  that  cannot 
be  described,  but  is  known  by  medical  prac- 
titioners as  the  "  facies  Hippocratica."  The  eye 
lias  a  suffused  and  glassy  look,  and  there  is  a 
certain  wildness  of  expression  very  character- 
istic. The  forehead  is  bedewed  with  a  cold 
and  clammy  sweat ;  the  extremities  become 
cold;  the  sensorium  is  affected  with  the  low 


muttering  delirium,  and  death  soon  finishes  the 
picture. 

These  symptoms  have  been  laid  down  as 
indicative  of  mortification  having  taken  place, 
probably  because  the   protruded   viscus  has 
generally  been  found  in  that  state  ;  and  from 
habit  many  practitioners  have  on  their  appear- 
ance in  cases  of  purely  idiopathic  peritonitis 
decided  on  the  presence  of  gangrene,  and  the 
hopelessness  of  recovery.    Such  cases  are  hope- 
less, and  patients  have  died,  but  not  of  mortifi- 
cation, for  although  these  symptoms  are  present 
in  most  cases  of  fatal  peritonitis,  yet  dissection 
after  death  very  rarely  exhibits  gangrene  in  that 
disease,  and  perhaps  for  this  reason,  that  the 
functions  of  the  abdominal  viscera  are  too  im- 
portant to  life  for  a  patient  to  struggle  suffici- 
ently lonrj  with  their  inflammation  to  permit  of 
mortification  being  established.     Whilst  the 
inflammation  is  very  active,  and  the  serous 
membrane  dry,  or  lymph  only  secreted  on  its 
surface,  then  is  the  pain  intense,  and  the  first 
order  of  symptoms  developed  :  but  when  effu- 
sion has  taken  place,  and  the  vessels  are  relieved 
by  the  pouring  forth  of  serum  or  sero-purulent 
fluid,  the  pain  abates,  and  the  symptoms  are 
those  of  extreme  debility.    In  confirmation  of 
this  remark  it  may  be  observed  that,  when  a 
patient  dies  from  any  sudden  effusion  into  the 
peritoneal  cavity,   whether  from  a  ruptured 
intestine,  or  gall-bladder,   or  bloodvessel,  or 
from  any  other  source,  the  symptoms  from  the 
very  commencement  are  those  of  debility  and 
collapse — the  same  sunken  and  anxious  look, 
the  same  feeble  and  fluttering  pulse,  and  the 
same  kind  of  universal  sinking  of  the  entire 
system. 

However,  although  the  symptoms  may  be 
very  formidable,  the  state  of  the  patient  is  not 
altogether  hopeless.  Art  may  still  accomplish 
a  great  deal,  and  even  the  operations  of  nature 
alone  and  unassisted  may  succeed  in  prolonging 
life,  although  under  circumstances  that  render 
life  scarcely  desirable.  When  the  hernia  has 
proceeded  to  gangrene  and  the  patient  still 
lives,  the  skin  of  the  tumour  assumes  a  very 
dark  red  and  livid  colour,  and  then  becomes 
black  in  spots.  The  cuticle  separates  and  peels 
off  in  patches,  and  some  one  or  other  of  the 
sphacelated  parts  giving  way,  a  profuse  dis- 
charge bursts  forth,  of  a  horribly  offensive 
nature.  In  the  same  way  may  the  surgeon's 
interference  prove  serviceable.  It  is  related  by 
Petit,  that  travelling  once,  he  met  in  the  out- 
house of  an  inn  an  unfortunate  being  thrown 
on  a  heap  of  straw  in  a  corner  to  die.  He  im- 
mediately recognized  the  smell  of  a  gangrened 
hernia,  and  proceeded  to  give  the  poor  fellow 
all  the  relief  within  his  power.  He  made  an 
incision,  allowed  the  feculent  matter  to  escape, 
cleared  away  the  gangrenous  and  putrid 
parts,  and  having  ordered  a  poultice  left  him 
to  his  fate.  On  his  return  he  found  him  able 
to  move  about  and  perform  active  service  within 
the  stable,  and  even  free  from  the  disagreeable 
accompaniment  of  an  artificial  anus  at  the 
groin.  This  is  a  most  gratifying  piece  of  suc- 
cessful surgery,  but  it  is  not  one  that  is  very 
frequently  realised.    In  order  to  the  possibility 


748 


HERNIA. 


of  an  artificial  anus  being  formed,  the  patient 
and  the  hernia  must  be  placed  under  circum- 
stances so  very  peculiar  that  it  will  be  easily 
perceived  how  unlikely  it  is  that  they  should 
be  united  and  combined  in  one  individual. 

1 .  Although  the  protruded  viscus  has  become 
sphacelated,  the  inflammation  within  the  ab- 
domen must  not  have  reached  such  a  height  as 
to  preclude  the  possibility  of  recovery. 

2.  Adhesions  must  be  established  between 
the  bowel  and  the  peritoneum  either  at  or  im- 
mediately above  the  neck  of  the  sac,  so  that 
when  the  stricture  is  free  and  the  enormous 
alvine  accumulation  allowed  to  escape,  it  will 
be  impossible  for  the  gut  to  withdraw  itself 
within  the  cavity  or  be  removed  from  the 
external  aperture. 

And  in  order  that  the  annoyance  of  the  arti- 
ficial anus  should  be  subsequently  removed,  it 
is  necessary  that  the  intestine  and  the  perito- 
neum to  which  it  is  adherent  should  retire  into 
the  abdomen,  and  that  the  angle  between  the 
two  intestinal  tubes  should  be  diminished  or 
removed. 

1.  If  the  first  of  these  conditions  is  indispen- 
sable, it  follows  that  the  chance  of  recovery 
with  artificial  anus  is  inversely  as  the  acuteness 
of  the  symptoms  and  the  rapidity  of  their  pro- 
gress.   As  it  is  the  inflammation  of  the  intes- 
tines that  destroys  the  patient,  it  is  pretty  evi- 
dent that  after  it  has  reached  a  given  point,  no 
operation  performed  on   the  hernia  and  no 
evacuation  of  the  contents  of  the  bowels  can 
arrest  its  progress,  or  cause  the  absorption  of 
the  lymph,  or  of  the  sero-purulent  fluid  that 
has  been  effused  into  the  peritoneal  cavity.  In 
operating  on  the  living  subject  within  twenty- 
three  hours  after  the  first  appearance  of  the 
hernia,  I  have  found  the  intestine  sphacelated  : 
in  this  case,  when  the  stricture  was  divided,  the 
discharge  from  the  intestines  within  the  ab- 
domen was  trifling  in  quantity,  and  in  order  to 
relieve  the  patient,  I  was  obliged  to  introduce 
a  gum-elastic  tube  for  a  considerable  way  into 
the  superior  fragment  of  the  bowel.    He  died 
on  the  subsequent  day,  and  on  examining  the 
body  the  front  of  the  intestines  seemed  to  be 
one  mass  of  plastic  lymph,  which  obliterated 
every  appearance  of  convolution,  and  must  have 
glued  together  the  bowels  in  such  a  manner  as 
to  prevent  the  possibility  of  a  peristaltic  motion. 
In  a  case  so  aggravated  no  hope  could  be  enter- 
tained from  the  establishment  of  an  artificial 
outlet.    It  can  now  be  easily  imagined  how 
persons  of  a  very  advanced  age,*  and  in  whom 
the  symptoms  of  strangulation  are  mild  and 
chronic,  recover  with  artificial  anus,  in  short 
that  such  a  consummation  is  most  to  be  ex- 
pected in  the  cases  to  which  the  name  "  incar- 
cerated" has  been  applied,  whereas  in  most 
instances  of  "  strangulated"  hernia  its  occurrence 
is  unlikely,  and  in  many  altogether  impossible. 

2.  The  second  great  requisite  for  the  esta- 
blishment of  an  artificial  anus  is,  that  adhesion 
shall  take  place  between  the  bowel  and  the 
peritoneum,  either  at  or  immediately  above  the 

*  See  Louis'  Memoir  on  hernia  followed  by  gan- 
grene.   Mem.  de  l'Acad.  Uoy.  v.  8. 


neck  of  the  sac,  so  that  when  the  stricture  is 
free  and  the  alvine  discharges  allowed  to  escape, 
it  will  be  impossible  for  the  gut  to  withdraw 
itself  within  the  cavity,  or  be  removed  from  the 
external  aperture.   This  adhesion  has,  I  think, 
been  generally  supposed  to  occur  "during  the 
inflammation  which  precedes  the  gangrene,"* 
but  is  nevertheless  probably  always  not  only 
subsequent  to  it,  but  to  the  separation  of  the 
unsound  and  sphacelated  parts;  and  the  at- 
tachment is,  not  between  the  contiguous  and 
opposing  smooth  surfaces  of  the  serous  mem- 
brane, but  between  the  divided  edges  of  the 
sound  portions  of  the  tube  remaining  after  the 
slough  has  been  thrown  off,  and  the  part  of  the 
neck  of  the  sac  adjacent  to  them.    I  have  ope- 
rated on  a  great  number  of  gangrened  herniae, 
and  never  found  such  an  adhesion  to  have  pre- 
viously existed,  neither  have  I  ever  met  with  it 
on  dissection,  and  I  cannot  conceive  the  possi- 
bility of  a  spontaneous  return  after  sphacelus 
(an  event  that  but  too  frequently  occurs)  if  the 
parts  were  thus  attached  together.  Assuredly 
if  such  adhesions  were  formed  at  so  early  a 
period,  they  ought  to  be  much  more  frequently 
found,  and  they  would  be  amongst  the  most 
calamitous  complications  that  could  attend  a 
hernia  ;  for  they  would  offer  an  almost  invinci- 
ble obstacle  to  its  reduction,  or  supposing  the 
bowel  to  have  been  pushed  up  by  force,  such  a 
sharp  angular  fold  would  be  formed  as  must 
prevent  the  passage  of  its  contents  and  create 
an  internal  strangulation.    Nor  is  the  consider- 
ation of  this  fact  practically  unimportant,  if  it 
leads  us  to  adopt  every  possible  precaution 
that  may  conduce  to  the  undisturbed  progress 
of  this  adhesive  process,  and  at  the  same  time 
warns  us  not  to  be  too  sanguine  in  our  expecta- 
tions.   I  have  (as  I  have  said)  operated  on  a 
vast  number  of  cases  of  gangrened  hernia,  not 
one  of  which  recovered  with  artificial  anus: 
some,  the  great  majority,  perished,  as  has  been 
remarked,  in  consequence  of  the  inflammation 
within  the  abdomen  having  reached  an  incurable 
height ;  some  others  sank  exhausted  and  died, 
the  system  being  apparently  worn  out  and 
incapable  of  a  recuperative  effort :  others  still, 
from  a  retraction  of  the  divided  end  of  the  bowel 
and  the  escape  of  its  contents  into  the  cavity; 
and  one,  from  a  cause  which,  as  it  has  not  been 
mentioned  by  any  pathological  writer,  may  be 
noticed  here.    On  the  spontaneous  separation 
of  the  sphacelated  bowel,  a  frightful  and  incon- 
trollable  hemorrhage  took  place,  some  of  which 
flowed  into  the  peritoneal  cavity,  and  was  found 
after  death  diffused  through  the  convolutions  of 
the  intestines. 

When  a  case  has  been  so  fortunate  as  to 
permit  of  the  formation  of  an  artificial  anus, 
after  the  mortified  parts  and  putrid  sloughs 
have  been  removed  a  cavity  is  seen,  generally 
irregular  and  puckered  at  its  edge,  leading 
down  to  and  communicating  with  the  injured 

*  Scarpa  on  hernia,  p.  323.  See  also  Travers  on 
wounded  intestines.  "  Dans  les  hernies,  ces  adhe- 
rences  precedent  la  destruction  des  parties,  et  elles 
previennent  le  plus  souvent  1'epanchernent  des 
matieres  dans  le  ventre." — Dupuytren,  Lecons 
Oralcs,  torn.  ii.  p.  197. 


HERNIA, 


?40 


intestine,  from  which  the  fecal  discharge  is 
constantly  trickling,  and  as  there  is  often  a  suffi- 
cient space  for  a  portion  of  this  to  lodge  and 
remain,  it  may  prove  a  source  of  troublesome 
and  dangerous  ulcerations.  In  a  short  time 
the  mucous  membrane  becomes  everted  and 
protrudes,  often,  if  neglected,  to  the  extent  of 
several  inches :  it  is  a  true  prolapsus  of  the 
membrane,  not  very  unlike  the  prolapsus  ani  in 
appearance.  At  the  bottom  of  the  cavity  al- 
ready mentioned,  are  the  orifices  of  the  intes- 
tines, the  superior  of  which  is  the  larger,  as  it  is 
from  it  the  discharge  proceeds,  whilst  the 
inferior  is  small  and  so  contracted  as  frequently 
to  be  discovered  with  difficulty.  The  partition 
between  the  orifices  is  formed  by  the  juxta- 
position and  adhesion  of  the  sides  of  the  intes- 
tine :  it  is  termed  the  "  eperon"  by  Dupuytren, 
and  is  larger  and  more  obvious  when  a  portion 
of  the  bowel  has  been  completely  removed  so 
as  to  divide  the  tube  into  two  parts,  smaller 
when  only  a  knuckle  has  been  pinched  up  and 
gangrened  without  engaging  the  entire  circum- 
ference. To  this  "  eperon"  and  double  partition 
the  mesentery  is  attached,  and  the  functions  of 
this  membranous  ligament  are  said  to  exert  a 
very  important  influence  on  the  progress  and 
after-consequences  of  artificial  anus. 

Not  only  is  the  superior  portion  of  the  intes- 
tine (that  which  is  in  relation  with  the  stomach) 
larger,  but  its  extremity  being  fixed  by  the  new 
adhesions,  the  progress  of  its  contents  is  greatly 
facilitated,  and  according  to  Dupuytren  actually 
accelerated  as  to  time.  The  inferior  or  rectal 
portion,  not  performing  its  functions,  becomes 
diminished  in  calibre,  and  contains  a  white, 
pulpy,  albuminous  material,  which  is  sometimes 
discharged  by  stool,  but  may  remain  undecom- 
posed  within  it  for  months  or  even  years.  The 
contracted  condition  of  this  portion  of  the  gut 
is  of  the  highest  importance  to  be  attended  to 
in  all  instances  where  a  recovery  is  possible  or 
likely  to  be  attempted.  This  disposition  of  all 
hollow  structures  in  the  body  to  accommodate 
themselves  to  the  bulk  or  quantity  of  their  con- 
tents has  been  already  noticed,  and  to  obviate 
the  inconveniences  likely  to  arise  from  such 
diminution,  the  older  surgeons*  strongly  recom- 
mended the  use  of  enemata,  in  order,  amongst 
other  advantages,  to  preserve  the  intestine  in  a 
sufficient  state  of  distension. 

The  progress  and  termination  of  a  case  such 
as  has  been  under  consideration  may  be  ex- 
tremely variable.  The  aperture  may  be  situa- 
ted in  the  lesser  intestine  so  high  up  or  so  near 
the  stomach  that  the  space  to  be  traversed  by 
the  aliments  and  their  period  of  detention  are 
shortened  :  their  digestion  is  then  incomplete 
and  nutrition  so  far  impaired  that  the  patient 
sinks  gradually,  and  dies  from  the  effects  of 
inanition ;  or  a  permanent  artificial  anus  may 
be  established  without  a  hope  or  a  chance  of  the 
natural  passage  ever  being  restored ;  and  this 
seemed  at  one  time  to  have  been  the  great 
object  of  surgical  practice  in  these  cases,  for  we 
find  M.  Littre,  a  celebrated  French  surgeon, 
actually  tying  up  the  lower  portion  of  the  gut 

*  See  Louis'  Memoir,  loc.  citat. 


when  he  could  find  it,  as  if  to  preclude  for  ever 
a  possibility  of  the  continuity  of  the  tube  being 
restored.  This  is  a  most  deplorable  condition, 
yet  have  patients  endured  the  annoyance  of  a 
permanent  discharge  at  the  groin  for  a  great 
length  of  time  ;  and  in  the  Museum  of  the 
School  in  Park  Street,  there  is  a  preparation 
taken  from  a  man  who  had  thus  existed  for 
upwards  of  ten  years.  There  is  a  curious  in- 
stance mentioned  by  Louis  in  which  something 
resembling  the  regular  action  of  a  sphincter  was 
clearly  observable,  and  although  the  discharge 
of  the  faeces  was  involuntary,  yet  it  was  periodical, 
and  the  gut  once  evacuated  remained  closed 
until  a  new  accumulation  took  place.  This 
person,  of  course,  was  comparatively  free  from 
that  constant  trickling  of  feces  which  is  the 
patient's  chief  annoyance,  and  which,  if  not 
palliated  by  some  ingenious  contrivance,  abso- 
lutely renders  his  life  loathsome. 

The  natural  passage  of  the  feces  has  been 
restored.  This  is  so  desirable,  so  fortunate  a 
consummation,  and  its  practicability  so  clearly 
established  by  the  circumstance  of  its  being  oc- 
casionally accomplished  solely  by  the  operations 
of  nature,  that  it  can  be  no  matter  of  surprise 
if  surgeons  have  laboured  to  attain  it  and  dili- 
gently observed  the  entire  process.  An  intes- 
tine of  which  a  portion  has  sloughed  away  is 
placed  in  a  very  different  condition  from  one 
that  has  been  simply  wounded.  When  an  en- 
tire loop  of  bowel  has  been  removed,  the  two 
portions  within  the  abdomen  passing  down  to 
the  neck  of  the  sac  lie  more  or  less  parallel  to 
each  other,  or  approach  by  a  very  acute  angle  : 
they  are  in  the  same  degree  perpendicular  to 
the  ring,  and  between  them  is  that  double  parti- 
tion termed  "eperon"  or  buttress  by  Dupuy- 
tren, and  the  "  promontory"  by  Scarpa.  Novv  as 
the  intestines  are  fixed  and  fastened  in  this  posi- 
tion, the  canal  can  never  again  become  conti- 
nuous in  directum,  and  therefore  any  material 
that  passes  from  the  upper  into  the  lower 
portion  must  do  so  by  going  round  this  inter- 
vening promontory.  Even  when  only  a  small 
fold  or  knuckle  has  been  lost,  although  the 
complete  continuity  of  the  tube  is  not  destroyed, 
and  the  partition  is  less  evident  and  prominent, 
still  an  angle  must  inevitably  be  formed  of  suffi- 
cient acuteness  materially  to  impede  the  pro- 
gress of  the  feces.  In  neither  case,  then,  can 
the  wounded  edge  of  one  portion  of  the  intes- 
tine come  to  be  applied  to  that  of  the  other, 
nor  can  adhesion  or  union  by  the  first  intention 
ever  be  accomplished  between  them.  In  lieu 
of  this,  however,  the  edges  of  the  intestine  be- 
come united  with  the  peritoneum  opposed  to 
them,  which  must  of  necessity  be  the  neck  of 
the  sac,  and  then  if  the  external  wound  can  be 
healed,  a  membranous  pouch  or  bag  is  inter- 
posed between  them,  of  a  funnel-shape,  and 
which  serves  as  a  medium  of  communication 
and  of  conveyance  for  the  fecal  matters  from 
one  portion  of  the  tube  into  the  other. 

Reflecting  on  this  pathological  condition  of 
parts,  it  will  not  be  very  difficult  to  explain  some 
of  the  varieties  observed  in  cases  of  artificial  anus. 
The  chief  obstruction  to  the  re-establishment  of 
the  canal  is  the  intervention  of  the  promontory. 


750 


HERNIA. 


If  it  is  so  large  or  otherwise  so  circumstanced 
as  entirely  to  impede  communication,  and  if 
in  this  condition  it  is  neglected,  the  discharge 
must  take  place  at  the  groin,  and  the  disease  is 
permanent.  Such,  I  believe,  is  the  history  of 
most  of  those  unhappy  beings  who  have  borne 
about  them  for  years  this  loathsome  and  dis- 
gusting affliction,  until  relieved  by  a  deatli  that 
could  not  have  proved  unwelcome.  In  a  vast 
number  of  cases  the  projection  is  not  so  great, 
and  although  it  may  impede  and  delay,  it  does 
not  altogether  prevent  the  passage  of  fasces 
from  one  portion  of  the  tube  to  the  other : 
then  as  the  external  wound  contracts,  the  neck 
of  the  sac  forms  into  a  membranous  funnel  or 
canal  of  communication,  and  the  fseces  begin 
to  pass.  The  wound  then  heals,  in  some  in- 
stances leaving  a  small  fistulous  opening 
through  which  a  limpid,  straw-coloured,  but 
fetid  fluid  constantly  distils,  whilst  in  others  a 
perfect  and  complete  cicatrix  is  formed.  But 
we  must  recollect  what  happens  in  this  seem- 
ingly perfect  cure  before  we  can  fully  appreci- 
ate the  entire  nature  of  the  case,  and  the  degree 
of  danger  that  always  overhangs  it.  It  is 
evident  that  the  viscus  must  (at  least  at  first) 
be  firmly  fixed  at  the  situation  of  the  cicatrix  ; 
that  it  no  longer  enjoys  any  freedom  of  motion, 
and  that  it  forms  an  angle  more  or  less  acute  at 
the  place  of  adhesion.  It  is  also  probable  that 
the  diameters  of  the  two  portions  of  intestine  do 
not  correspond.  Hence  the  process  of  diges- 
tion is  impaired,  the  patient  must  study  every 
article  of  food  he  consumes,  and  the  slightest 
indiscretion  is  followed  by  colicky  pains,  flatu- 
lence, and  tormina  of  the  bowels ;  often  there  is 
nausea,  vomiting,  loss  of  appetite,  and  a  drag- 
ging sensation  at  the  stomach,  this  latter  symp- 
tom being  explained  by  the  omentum  having 
formed  a  part  of  the  protrusion,  and  become  ad- 
herent at  the  new-formed  cicatrix.  It  often 
happens  that  the  scar  gives  way,  and  a  facal 
discharge  takes  place  again,  the  groin  thus 
alternately  healing  up  and  bursting  out  anew. 
This  is  more  likely  to  occur  in  cases  where  the 
very  small  fistulous  canal  has  remained,  and 
therefore  many  surgeons  have  regarded  this 
event  as  more  fortunate  than  where  the  cica- 
trization has  been  complete ;  for  the  course  of 
the  fistula  serves  as  a  guide  to  direct  the  burst- 
ing of  the  accumulation  externally,  whereas  if, 
as  sometimes  happens,  the  intestine  should  give 
way  internally,  its  contents  are  then  poured 
out  into  the  peritoneal  cavity,  and  the  result 
must  be  inevitably  fatal. 

The  most  curious  circumstance  connected 
with  the  healing  of  an  artificial  anus  is,  that 
the  position  of  the  united  intestines  and  the 
intervening  infundibulum  or  funnel  behind  the 
cicatrix  is  not  permanent.  "  It  is,"  says  Scarpa,* 
"  a  certain  fact  confirmed  by  a  very  great  num- 
ber of  observations,  that  after  the  separation  of 
the  gangrene  the  two  sound  segments  of  intes- 
tine retire  gradually  beyond  the  ring  towards 
the  cavity  of  the  abdomen,  notwithstanding  the 
adhesion  which  they  have  contracted  with  the  neck 
of  the  sac,  whether  this  is  caused  by  the  tonic 


and  retractile  action  of  the  intestine  itself  and 
of  the  mesentery,  or  rather  by  the  puckering  of 
the  cellular  substance,  which  unites  the  hernial 
sac  to  the  abdominal  parietes  within  the  ring. 
And  this  phenomenon  is  likewise  constant  and 
evident  even  in  herniae  not  gangrenous,  but 
merely  complicated  with  fleshy  adhesions  to 
the  neck  of  the  sac,  and  therefore  irreducible. 
In  these  hernia;,  the  immediate  cause  of  stran- 
gulation being  removed,  the  intestine,  together 
with  the  hernial  sac,  gradually  rises  up  towards 
the  ring,  and  at  last  is  concealed  behind  it." 
The  same  fact  has  been  observed  by  Dupuy- 
tren,*  who  attributed  it  to  the  continued  action 
of  the  mesentery  on  the  intestine.  Many  indi-. 
viduals  who  had  been  cured  of  artificial  anus 
without  operation  returned  to  the  Hotel  Dieu 
at  very  remote  periods,  and  died  of  diseases 
having  no  relation  to  the  original  complaint. 
The  parts  were  curiously  and  carefully  examined, 
and  the  intestine,  instead  of  being  fixed  to  the 
walls  of  the  belly,  was  found  free  and  floating 
within  the  cavity.  There  could  be  no  doubt 
of  the  identity  of  the  individuals,  and  moreover 
a  fibrous  cord  was  seen  extended  from  the  point 
of  the  wall  of  the  abdomen  which  corresponded 
with  the  former  artificial  anus,  to  the  intestine. 
This  cord,  some  lines  in  diameter  and  some 
inches  in  length,  thicker  at  its  extremities  than 
in  the  middle,  covered  by  peritoneum,  and 
formed  entirely  by  a  cellular  and  fibrous  tissue 
without  any  cavity,  was  evidently  produced 
by  the  progressive  elongation  of  the  cellular 
membrane  that  had  united  the  intestine  to  the 
wall  of  the  abdomen  ;  and  the  cause  which 
had  occasioned  this  elongation  was  nothing 
else  than  the  traction  exercised  by  the  mesentery 
on  the  intestine  in  the  different  motions  of  the 
body  during  life. 

Having  now  endeavoured  to  describe  gene- 
rally the  circumstances  or  conditions  under 
which  protrusions  of  the  abdominal  viscera  may 
exist,  I  proceed  to  consider  the  peculiarities 
that  arise  from  situation,  premising  that  it  is 
not  my  intention  to  enter  very  minutely  into 
the  descriptive  anatomy  of  those  several  situa- 
tions in  their  normal  or  healthy  states,  but  only 
in  reference  to  and  in  connexion  with  the  ex- 
istence of  the  disease  under  consideration. 

Inguinal  hernia. — When  a  viscus  is  pro- 
truded through  one  or  both  of  the  apertures 
termed  rings,  situated  at  the  anterior  and  infe- 
rior part  of  the  abdomen,  near  the  fold  of  the 
groin,  but  above  Poupart's  ligament,  the  hernia 
is  termed  inguinal.  It  may  exist,  therefore,  in 
three  different  conditions.  1.  Where  the  in- 
testine has  been  pushed  through  the  internal 
ring  only,  and  is  lodged  in  the  inguinal  canal : 
it  then  appears  as  a  small,  round,  firm,  and 
moderately  elastic  tumour.  2.  Where  it  has 
passed  through  the  internal  ring,  through  the 
inguinal  canal,  through  the  external  ring,  and 
dropping  down  into  the  scrotum  of  the  male  or 
the  labium  pudendi  of  the  female,  appears  as  a 
larger  and  more  yielding  tumour,  of  a  pyrami- 
dal shape,  the  apex  of  the  pyramid  being  di- 
rected towards  the  anterior  superior  spinous 


*  Scarpa,  op.  citat.  p.  313. 


*  Le9ons  Orales,  torn.  ii.  p.  207. 


HERNIA. 


751 


process  of  the  ilium.  As  these  are  but  different 
stages  of  the  same  disease,  both  come  under  the 
appellation  of  hernia  by  the  oblique  descent. 
But,  3,  when  the  viscus  has  been  forced 
through  the  parietes  immediately  behind  the 
external  ring,  and  passes  out  through  that  natural 
aperture  only,  it  is  then  for  obvious  reasons 
termed  the  hernia  by  direct  descent;  and 
although  the  external  characters  of  the  tumour 
are  not  always  such  as  to  point  out  the  peculiar 
nature  of  this  protrusion,  yet  the  relative  posi- 
tion of  the  intestine  with  respect  to  adjacent 
parts  must  be  somewhat  different  in  these  seve- 
ral cases,  a  difference  that  will  be  found  to  be 
of  some  practical  importance. 

The  peritoneal  sac,  as  viewed  internally  in 
the  direction  of  the  iliac  and  inguinal  regions, 
is  described  by  Scarpa  as  being  divided  into 
two  great  depressions  at  each  side,  the  medium 
of  partition  being  the  ligament  into  which  the 
umbilical  artery  of  the  foetus  had  degenerated, 
together  with  the  fold  of  peritoneum  raised  by 
that  ligament.  Of  these  fossa?  the  superior  or 
external  is  the  larger  and  deeper;  it  is  that 
within  which  the  intestines  are  collected  when 
strongly  compressed  by  the  abdominal  muscles 
and  by  the  diaphragm  in  any  violent  exertion ; 
and  from  it  inguinal  hernia  is  most  frequently 
protruded,  as  the  ligament  and  duplicature  of 
the  peritoneum  prevent  the  compressed  viscera 
lodged  in  this  fossa  from  removing  out  of  it  to 
descend  into  the  pelvis.  The  situation  of  the 
umbilical  artery  varies  considerably :  some- 
times it  is  close  upon  the  internal  border  of  the 
internal  ring,  in  other  subjects  at  the  distance 
of  half  an  inch  from  it,  or  even  more ;  but  it  is 
always  at  the  pubic  side  of  the  epigastric  ves- 
sels. Thus,  in  its  direction  upwards  and  in- 
wards towards  the  umbilicus  it  crosses  ob- 
liquely behind  the  inguinal  canal :  all  hernia?, 
therefore,  by  the  oblique  descent  pass  out  from 
the  external  or  superior  abdominal  fossa,  while 
those  by  the  direct  are  in  relation  to  and  are 
protruded  from  the  inferior  or  internal.  Inde- 
pendent of  this  configuration  there  is  nothing 
in  the  peritoneal  cavity  as  viewed  from  within, 
to  determine  the  occurrence  of  hernia  at  one 
place  rather  than  at  another.  The  membrane 
is  in  all  parts  equally  smooth  and  polished, 
equally  strong,*  tense,  and  resisting.  This, 
however,  is  not  the  case  with  respect  to  the 
muscular  and  tendinous  walls  of  the  abdomen, 
which  vary  very  considerably  in  density  and 
strength  in  different  situations,  and  in  these 
qualities  dissection  shews  that  the  hypogastric 
or  inguinal  regions  are  the  most  deficient  and 
therefore  most  disposed  to  permit  of  the  occur- 
rence of  hernia. 

In  prosecuting  the  dissection  from  within 
(which  is  by  far  the  most  satisfactory  manner), 
the  peritoneum  may  be  detached  by  the  fingers 
or  by  the  handle  of  the  knife  in  consequence  of 
the  laxity  of  the  cellular  tissue  connecting  it  to 

*  The  strength  of  the  peritoneum  is  proved  by  a 
curious  experiment  of  Scarpa's.  He  stretched  a 
large  circle  of  this  membrane  recently  taken  from 
the  dead  body,  on  a  hoop  like  a  drum,  and  found 
it  capable  of  supporting  a  weight  of  fifteen  pounds 
without  being  ruptured. 


the  adjacent  external  structures.  The  fascia 
transversalis  then  comes  into  view,  and  in  it  the 
aperture  termed  the  internal  ring,  through 
which  the  spermatic  cord  in  the  male,  and  the 
round  ligament  in  the  female  are  transmitted. 
This  aponeurosis  varies  in  density  and  thick- 
ness in  different  individuals  :  it  is  continuous 
with  the  fascia  iliaca,  and  is  connected  with 
the  posterior  edge  of  Poupart's  ligament :  it  is 
denser  and  stronger  externally,  and  becomes 
weaker  and  more  cellular  as  it  approaches  the 
mesial  line.  Where  the  internal  oblique  is 
muscular,  the  connexion  between  it  and  the 
fascia  transversalis  is  extremely  lax,  cellular,  and 
easily  separable ;  but  after  it  becomes  tendi- 
nous, the  union  is  much  more  intimate,  and  the 
fibres  of  the  one  can  scarcely  be  distinguished 
from  those  of  the  other  unless  by  the  difference 
of  their  direction.  In  most  subjects  the  internal 
ring  is  very  indistinct,  its  size,  shape,  and  direc- 
tion being  in  general  determined  rather  by  the 
knife  of  the  anatomist  than  by  nature.  So  far 
as  the  fascia  is  concerned,  the  external  inferior 
border  of  the  ring  is  its  strongest  part,  but  its 
internal  edge  seems  to  be  the  stronger  as  it  is 
supported  by  the  epigastric  vessels,  and  some- 
times by  the  remnant  of  the  umbilical  artery. 
Its  size  is  about  an  inch  in  length,  half  an  inch 
in  breadth  ;  its  shape  oval ;  and  the  direction 
of  its  longest  diameter  perpendicular  or  slightly 
inclining  from  above  downwards  and  outwards. 

The  position  of  the  epigastric  artery  with  re- 
spect to  the  neck  of  the  sac  at  once  points  out 
whether  a  hernia  is  by  the  direct  descent  or  not, 
for  it  marks  the  internal  or  pubic  boundary  of 
the  internal  ring.  This  vessel  is  occasionally 
irregular  in  its  origin,  but  in  its  normal  or  usual 
state  it  comes  off  from  the  external  iliac  before  it 
has  reached  Poupart's  ligament,  and  conse- 
quently in  that  position  it  lies  behind  the  bag 
of  the  peritoneum,  which  it  passes  by  forming 
an  arch,  the  concavity  of  which  is  directed  up- 
wards. It  then  appears  in  front,  between  the 
fascia  transversalis  and  the  peritoneum,  but 
more  closely  attached  to  the  former,  with  which 
it  remains  when  the  membrane  is  torn  away. 
The  vas  deferens  is  seen  coming  from  the  pel- 
vis obliquely  upwards  and  outwards  until  it 
reaches  the  spermatic  artery,  which,  having  de- 
scended from  above,  nearly  in  a  perpendicular 
direction,  meets  the  vas  deferens  at  rather  an 
acute  angle,  the  former  being  to  the  outside  and 
nearly  in  front  of  the  latter.  These  vessels 
having  passed  the  fascia  transversalis  disappear 
by  arching  round  the  epigastric  artery  and  en- 
tering the  inguinal  canal,  and  they  define  the 
inferior  margin  of  the  internal  ring.  The  re- 
mainder of  its  border  is  not  so  very  distinctly 
marked,  partly  in  consequence  of  a  very  deli- 
cate fascia  which  is  given  off  from  it  and  passes 
down  a  short  way  on  the  spermatic  cord,  where 
it  becomes  indistinct  and  is  lost;  and  partly 
because  the  transversalis  muscle  lying  before  it 
renders  the  view  obscure.  The  internal  border 
of  the  internal  ring  is  always  (as  stated  by  Sir 
A.  Cooper)  midway  between  the  anterior 
superior  spinous  process  of  the  ilium  and  the 
symphysis  pubis. 

When  a  protruded  viscus,  then,  is  passing 


752 


HERNIA. 


through  this  ring,  it  lias  the  epigastric  artery  to 
its  internal  or  pubic  side,  and  generally  the 
vessels  of  the  cord  behind  it ;  but  a  variety 
sometimes  occurs,  for  the  hernia  may  protrude 
exactly  at  the  spot  where  the  spermatic  artery 
and  vas  deferens  meet  each  other  at  an  angle, 
and  separate  these  vessels  from  each  other, 
leaving  the  artery  rather  to  the  outside  and  in 
front,  the  vas  deferens  still  occupying  its  usual 
situation  behind.  After  the  hernia  has  passed 
the  fascia  transversalis,  it  is  still  behind  the 
fibres  of  the  internal  oblique  and  transversalis 
muscles,  and  has  to  pass  a  few  lines  (the  dis- 
tance varying  in  different  subjects)  before  it 
reaches  the  posterior  surface  of  the  tendon  of 
the  external  oblique.  On  prosecuting  this  dis- 
section further  by  detaching  the  fascia  trans- 
versalis from  the  transversalis  muscle  in  a  di- 
rection downwards  and  outwards,  the  intestine 
will  be  found  to  have  entered  a  canal  of  an  inch 
and  a  quarter  to  an  inch  and  a  half  in  length, 
its  direction  being  obliquely  downwards  and 
inwards  to  the  external  ring.  This  is  termed 
the  inguinal  canal,  and  is  thus  formed.  Pou- 
part's  ligament,  whether  it  be  considered  as  a 
portion  of  the  tendon  of  the  external  oblique  or 
not,  is  powerfully  strong  and  thick  :  to  it  the 
fascia  transversalis  is  firmly  adherent  behind, 
and  the  thinner  and  more  expanded  fibres  of 
the  tendon  of  the  external  oblique  before. 
Between  these,  then,  a  sheath  is  formed  in 
which  the  hernia  is  lodged,  having  in  front  the 
tendon  of  the  external  oblique,  and  also  covered 
by  the  cremaster  muscle,  particularly  that  part 
of  it  which  has  its  origin  from  Poupart's  liga- 
ment. Behind  it  is  the  fascia  transversalis, 
and  more  internally  or  nearer  the  pubis  the 
conjoined  tendon  of  the  internal  oblique  and 
transversalis,  and  below  is  Poupart's  ligament. 
Above,  it  is  crossed  obliquely  by  the  inferior 
margin  of  the  internal  oblique  and  transversalis. 
These  muscles  have  a  fleshy  origin  from  the  ex- 
ternal third  of  Poupart's  ligament,  from  which 
they  pass  in  an  arched  form  to  be  inserted  by 
a  common  tendon  into  the  crest  of  the  pubis. 
Under  this  arch  the  viscus  slips  and  thus  places 
itself  anterior  to  the  conjoined  tendon  before 
passing  through  the  external  ring  and  becoming 
a  scrotal  hernia. 

Anatomists  have  not  agreed  in  their  descrip- 
tions of  the  internal  oblique  muscle,  although 
a  correct  and  accurate  knowledge  of  the  situa- 
tion of  it  and  of  the  transversalis  in  the  neigh- 
bourhood of  the  rings  is  indispensable  to  the 
right  understanding  of  hernia.  According  to  Sir 
A.  Cooper*  and  Lawrence,f  the  upper  part 
only  of  the  internal  ring  is  shut  up  by  these 
muscles, leaving  the  lower  unprotected,  and  con- 
sequently, according  to  this  view  of  the  subject, 
a  hernia  on  entering  the  inguinal  canal  should 
have  them  above  it.  CloquetJ  states  that  the 
inferior  border  of  the  transversalis  passes  on  a 
level  with  the  superior,  opening  internally,  but 
the  edge  of  the  internal  oblique  is  lower  down, 

*  Page  6. 

t  Lawrence  on  Ruptures,  p.  162. 
$  Anatomy  of  Hernia,  by  Jules  Cloquct,  trans- 
lated by  M'Whinnie,  p.  6. 


covers  the  spermatic  cord  in  the  inguinal  canal, 
and  passes  over  it  to  be  inserted  into  the  pubis 
at  the  point  where  it  escapes  from  the  inferior 
opening  of  the  canal,  that  is,  the  external  ring. 
Scarpa*  gives  a  different  description  still,  where 
he  says,  "  towards  the  side  at  about  eight  lines 
distance  from  the  apex  of  the  ring,  the  lower 
muscular  fibres  of  the  internal  oblique  muscle 
separate  from  each  other  to  allow  the  sper- 
matic cord  to  pass  between  them ;"  and 
Guthrief  considers  the  occasional  passage  of  a 
hernia  through  the  fibres  of  this  muscle,  and  its 
compression  by  them,  to  be  no  unfrequeut  cause 
of  strangulation.  It  is  not  easy  to  reconcile 
these  conflicting  authorities,  which  in  them- 
selves demonstrate  the  fact  that  the  inferior- 
border  of  this  muscle  exhibits  some  varieties  in 
its  relation  to  the  inguinal  canal  and  internal 
ring  according  to  the  extent  of  its  origin  from 
Poupart's  ligament.  When  a  hernia  is  present, 
I  have  always  seen  it  arched  over  the  neck  of 
the  sac,  and  although  I  would  by  no  means 
assert  that  a  rupture  never  takes  its  course 
between  these  muscular  fibres,  yet  I  have  not 
met  with  an  instance,  and  as  I  have  observed 
elsewhere,  I  imagine  such  an  occurrence  would 
create  a  deviation  from  the  usual  relative 
anatomy  of  the  cremaster  muscle  with  respect 
to  the  hernial  sac— See  Abdomen. 

The  inguinal  canal  terminates  in  front  at  the 
external  ring,  which  is  formed  by  a  separation 
of  the  fibres  of  the  external  oblique  muscle  as 
it  passes  inwards  and  downwards  to  be  inserted 
into  the  pubis.  Almost  immediately  after  the 
muscle  has  become  tendinous,  a  disposition  to 
this  separation  is  observable,  and  a  kind  of  split 
is  formed  in  the  tendon,  the  edges  of  which 
are,  however,  pretty  firmly  held  in  their  re- 
lative positions  by  fibres  passing  closely  and 
irregularly  across  from  one  to  the  other.  These 
fibres  have  been  called  the  intercolumnar  fascia. 
Besides  these  there  is  a  very  remarkable  ar- 
rangement of  tendinous  fibres  seeming  to  arise 
from  Poupart's  ligament,  and  thence  radiating 
in  an  arched  form  (the  convexity  of  the  arch 
looking  towards  the  pubis)  to  form  a  strong  in- 
terlacement with  the  fibres  of  the  external 
oblique.;];  Independent  of  these  adventitious 
bands  the  tendon  itself,  as  it  approaches  the  crural 
arch  and  the  pubis,  seems  to  become  thicker 
and  stronger ;  and  (as  has  been  remarked  by 
Scarpa)  in  the  dead  body  after  the  integuments 
are  removed  and  the  parts  left  for  some  time 
exposed,  the  lower  portion  of  the  aponeurosis 
appears  opaque  and  dense,  while  the  part  above 
the  umbilicus  preserves  its  transparency,  and 
allows  the  fleshy  fibres  of  the  subjacent  muscle 
to  be  seen  through  it.  The  separation  above 
alluded  to  being  effected,  the  tendon  is  divided 
into  two  portions,  termed  the  pillars  of  the 
ring :  the  anterior  or  internal  is  broader  and 
flatter,  and  runs  to  be  inserted  into  the  pubis  of 
the  opposite  side,  and  the  ligamentous  sub- 
stance that  covers  the  front  of  this  bone.  The 

»  Page  25. 

t  Anatomy  of  Hernia. 

|  Sometimes  termed  Camper's  fascia,  from  its 
being  so  admirably  delineated  in  the  "  Icones." 


HERNIA. 


753 


mferior  or  external  is  rounder  and  more  firm, 
and  attached  to  the  external  part  of  the  crest  or 
tuberosity  of  the  pubis.  A  triangular  aperture 
is  thus  formed  of  about  an  inch  or  an  inch  and 
a  quarter  in  length,  the  base  of  which,  nearly 
half  an  inch  across,  is  situated  at  the  pubis,  from 
which  it  tapers  gradually  off  in  a  direction 
upwards  and  outwards.  For  a  neat  demonstra- 
tion of  this  aperture  we  must  also  be  largely 
indebted  to  the  knife  of  the  anatomist,  its 
edges  being  obscured  by  a  fascia*  which  comes 
off  from  them,  and  passing  down  on  the  cord 
is  generally  of  sufficient  density  to  admit  of 
being  traced  as  far  as  the  tunica  vaginalis  testis. 
This  ring  is  never  well  developed  in  the  female, 
it  then  being  smaller,  rather  of  an  oval  figure, 
and  from  its  deficiency  of  size  appearing  to  be 
nearer  the  pubis  than  in  the  male :  even  in 
subjects  of  the  latter  sex  the  size  of  this  open- 
ing exhibits  considerable  variety.  When  a 
hernia  has  descended  through  it,  the  shape  and 
direction  of  the  external  ring  are  altered  :  the 
inferior  pillar  is  still  more  flattened  and  runs 
in  a  more  horizontal  direction  ;  the  superior  is 
banded  in  an  arched  form  rather  tightly  above 
it ;  the  shape  of  the  entire  ring  is  rendered  more 
oval  and  its  direction  more  horizontal ;  but  still 
its  relative  position  with  respect  to  the  bone  is 
so  far  preserved  that  no  hernia  can  pass,  with- 
out its  internal  edge  resting  on  this  bone. 

In  dissecting  a  hernia  of  this  description 
from  without,  after  removing  the  skin  and 
cellular  tissue  more  or  less  loaded  with  fat,  the 
fascia  superficialis  is  exposed.  This  is  a  tegu- 
ment investing  most  parts  of  the  body,  though 
far  more  dense  iu  some  situations  than  in 
others,  and  is  situated  beneath  the  subcuta- 
neous fat,  with  which  it  is  sometimes  so  much 
identified  as  to  render  its  demonstration  diffi- 
cult. At  the  groin  it  is  usually  well  developed, 
and  is  described  as  consisting  of  two  distinct 
lamina,  but  may  {by  such  as  are  curious  in 
these  dissections)  by  care  be  separated  into 
many  more.f  The  superficial  layer  is  very 
lax,  passes  over  and  has  no  connexion  with 
Poupart's  ligament,  and  is  very  generally  re- 
moved along  with  the  skin  and  fat  by  the  in- 
experienced dissector.  Its  removal  exposes 
some  of  the  glands  of  the  groin.  The  deep 
iayer  is  more  membranous,  and  possesses  more 
of  the  determined  character  of  a  fascia.  It 
adheres  intimately  to  the  muscular  fibres  of  the 
external  oblique,  passes  thence  inwards  over 
the  tendoB,  to  which  it  cannot  be  said  to  be 
attached,  as  the  connecting  cellular  tissue  is 
extremely  loose,  and  meets  its  fellow  of  the 
opposite  side  at  the  linea  alba,  to  which  both 
are  attached.  It  has  an  insertion  into  the 
pubis,  and  its  adhesion  to  Poupart's  ligament 
is  in  many  respects  extremely  intimate.  Pass- 

*  This  also  has  been  called  an  intercolumnar 
fascia,  and  a  spout-like  fascia,  &c.  It  is  to  be  re- 
gretted that  such  a  confusion  of  nomenclature  ob- 
tains in  the  description  of  these  parts, — a  confusion 
always  embarrassing  to  the  student,  and  rendering 
the  subject  uselessly  perplexing  and  difficult. 

t  Velpeau  describes  three  distinct  layers.  Ana- 
tomie  des  fiegions,  torn.  ii.  p.  70. 

VOI,.  II. 


ing  down  in  front  of  the  thigh,  it  covers*  several 
of  the  lymphatic  glands,  or  in  many  instances 
leaves  small  apertures  or  deficiencies  in  which 
glands  are  lodged  :  it  then  reaches  the  opening 
in  the  fascia  lata  for  the  transmission  of  the 
saphena  vein,  to  the  edge  of  which  it  adheres 
more  or  less  closely,  and  afterwards  descends 
upon  the  thigh,  having  this  vein  interposed 
between  it  and  the  fascia  lata.  At  the  external 
abdominal  ring  the  fascia  superficialis  sends 
down  a  sheath-like  process,  investing  the  cord 
and  descending  down  over  the  tunica  vaginalis 
and  the  testicle  :  it  must,  therefore,  under  any 
circumstances  give  a  covering  to  the  hernial 
sac.  On  the  removal  of  this,  the  fascia  that 
comes  from  the  edges  of  the  pillars  of  the  ring 
is  observed,  and  this  is  generally  much  thicker 
and  firmer  than  in  the  normal  condition  of  the 
parts.  When  so  thickened,  it  also  admits  of 
subdivision  into  several  laminae.  Immediately 
underneath  is  the  cremaster  muscle,  its  fibres 
spread  out  and  separated  so  as  to  resemble  a 
fascia,  though  in  some  instances  the  contrary  may 
be  observed,  and  they  are  seen  gathered  into 
bundles  and  greatly  thickened.  Still  deeper 
are  three  other  layers  of  fascia,  perhaps  derived 
from  that  which  comes  from  the  edges  of  the 
internal  ring,  and  finally  the  hernial  sac  is 
exposed. 

In  herniae  of  moderate  size,  the  spermatic 
artery,  veins,  and  the  vas  deferens  are  usually 
found  in  one  cord  and  enclosed  in  one  common 
sheath  lying  behind  the  sac  :  some  exceptions, 
however,  to  this  rule  are  observed,  one  of  which, 
wherein  the  bloodvessels  are  situated  on  its 
anterior  and  external  surface,  and  the  vas  defe- 
rens posteriorly  and  internally,  has  been  already 
noticed  and  explained.  But  there  is  another 
deviation  that  seems  to  be  occasioned  by  the 
growth  of  the  hernia,  and  the  compression  exer- 
cised by  it  on  the  cellular  substance  connecting 
the  constituent  parts  of  the  cord  together.  It 
can  therefore  only  be  met  with  in  large  and  old 
ruptures.  Thus,  as  the  tumour  increases,  it 
causes  this  cellular  tissue  to  be  stretched  just 
as  if  the  vas  deferens  and  the  artery  were  pulled 
asunder  in  different  directions,  whilst  the  sac 
insinuates  itself  between  them,  until  finally  the 
vessels  come  to  lie  on  one  side  of  the  hernia,  or 
it  may  be  to  occupy  its  anterior  surface.  The 
greatest  divarication  of  these  vessels  exists,  as 
might  a  priori  be  expected,  towards  the  lower 
part  of  the  tumour;  it  is  less  towards  the 
middle,  and  scarcely  if  at  all  above,  and  in  the 
vicinity  of  the  neck  of  the  sac.  A  knowledge 
of  this  fact  may  teach  us  to  beware  how  we 
prolong  an  incision  very  far  down  in  operating 
on  large  and  old  hernise. 

Perhaps  the  next  point  of  practical  import- 
ance to  consider  is,  whether,  with  all  this  ana- 
tomical and  pathological  information,  it  might 
nevertheless  be  possible  to  mistake  this  disease 
and  confound  it  with  any  other  affection.  The 

*  The  inguinal  glands  arc  generally  described  as 
lying  between  the  layers  of  the  superficial  fascia. 
On  dissection,  this  has  not  appeared  to  me  to  be 
the  case, 

3  D 


751 


HERNIA; 


hernia  just  described  may  exist  in  two  different 
conditions  ;  one,  in  winch  it  is  still  lodged  within 
the  inguinal  canal,  and  appears  in  the  form  of  a 
tumour  in  the  upper  part  of  the  groin,  termed 
bubonocele ;  the  other,  in  which  it  has  escaped 
through  the  external  ring,  and  having  dropped 
down  constitutes  scrotal  hernia. 

When  the  rupture  has  descended  no  farther 
than  the  groin,  there  are  but  two  affections  that 
can  bear  any  resemblance  to  it :  these  are,  the 
testis  itself  whilst  in  the  act  of  descending,  if 
this  process  has  been  delayed  beyond  the  usual 
period  of  life,  and  an  enlarged  inguinal  gland. 
However  possible  in  cases  of  crural  hernia  (as 
shall  be  noticed  hereafter),  a  mistake  of  the 
latter  description  is  not  likely  to  occur  in  the 
disease  under  consideration,  but  there  is  an  ob- 
servation of  Mr.  Colles  on  this  subject  de- 
serving of  attention.  "I  do  not  suppose," 
says  this  distinguished  professor,  "  that  any 
surgeon  of  competent  anatomical  knowledge 
could  mistake  it  for  inflammation  of  those 
lymphatic  glands  which  l,e  in  the  fold  of  the 
groin,  but  an  enlargement,  whether  from  a 
venereal  or  any  other  cause,  of  two  lymphatic 
glands  which  he  on  the  side  of  the  abdomen,  as 
high  up  but  rather  more  internally  than  the  in- 
ternal abdominal  ring;  an  enlargement  of  these 
glands  will  produce  appearances  resembling 
those  of  inguinal  hernia."*' 

It  seems  almost  surprising  how  the  descent 
of  the  testicle  could  possibly  be  mistaken  for 
a  hernia  when  the  mere  examination  of  the 
scrotum  would  throw  such  an  explanatory  light 
upon  the  subject,  but  a  consideration  of  the 
following  circumstances  will  be  useful  in  solving 
the  difficulty.    1st,  The  detention  of  the  tes- 
ticle within  the  abdomen  until  an  unusually 
late  period  is  by  no  means  so  infrequent  an  oc- 
currence as  is  generally  supposed  even  by  sur- 
geons in  considerable  practice  :  I  have  heard  a 
military  medical  officer  observe  on  the  great 
number  of  young  men  that  had  passed  before 
him  for  inspection  after  enlistment,  in  whom  one 
and  sometimes  both  the  testes  had  not  de- 
scended.   2d,  The  symptoms  of  both  affections 
bear  a  general  though  not  necessarily  a  close 
resemblance ;  for  the  situation  of  the  tumour 
is  exactly  the  same,  and  if  the  testicle  is  com- 
pressed and  inflamed,  the  pain  and  tenderness 
and  the  inflammatory  fever  are  to  a  certain  ex- 
tent like  the  symptoms  of  strangulation.  But 
I  have  not  met  the  same  costiveness,  at  least 
the  same  obstinate  resistance  of  the  bowels  to 
the  operation  of  aperient  medicines,  nor  the 
same  vomiting,  nor  the  same  exquisite  tender- 
ness spreading  over  the  abdomen,  and  the  pulse 
is  not  that  small,  thready,  hard,  and  rapid  vi- 
bration that  is  produced  by  peritoneal  inflam- 
mation.   In  one  case  I  perceived  that  pressure 
on  the  tumour  occasioned  that  sickening  pain 
and  sensation  of  faintness  which  a  slight  injury 
of  the  testicle  so  often  produces;  and  I  imagine 
that  in  this  case  a  light  and  very  gentle  per- 
cussion might  prove  a  useful  auxiliary  dia- 
gnostic.   But,  3rd,  it  does  not  always  happen 

*  Colles's  Surgical  Anatomy,  p.  46. 


that  the  surgeon  takes  sufficient  pains  to  inves- 
tigate the  disease  before  him.  "  He  is  apt," 
says  Mr.  Colles,*  "  at  once  to  set  down  the  case 
as  incarcerated  hernia,  a  complaint  with  which 
he  is  familiar,  and  does  not  suspect  the  exist- 
ence of  a  disease  which  is  to  him  perhaps  ex- 
tremely rare.  Boys  sometimes  indulge  in  the 
trick  of  forcing  up  the  testicles  into  the  ab- 
domen, which  may  be  followed  by  unhappy 
consequences,  for  the  gland  may  not  descend 
again,  or  if  it  does,  perhaps  a  portion  of  in- 
testine slips  down  along  with  and  behind  it, 
which  may  then  become  strangulated,  while  its 
presence  is  unsuspected  and  the  symptoms 
attributed  to  compression  of  the  testis."  A  boy, 
about  seven  years  of  age,  had  forced  the  left 
testicle  into  the  abdomen  :  ten  years  afterwards, 
the  inguinal  ring  having  probably  become  un- 
usually contracted,  the  testicle  passed  under  the 
femoral  arch  with  all  the  symptoms  of  stran- 
gulated hernia,  on  account  of  which  he  was 
obliged  to  undergo  the  operation. | 

When  the  hernia  has  become  scrotal,  it  then 
comes  more  to  resemble  diseases  of  the  testis 
and  of  the  cord,  but  in  general  these  are  very 
easily  distinguished,  and  there  are  only  three 
that  could  lead  a  practitioner  into  error,  and 
then  only  through  unpardonable  carelessness ; 
the  hydrocele  of  the  tunica  vaginalis  testis, 
the  hydrocele  of  the  spermatic  cord,  and  the 
varicocele  or  a  varicose  condition  of  the  veins 
of  the  cord. 

There  is  not  much  likelihood  that  hydrocele 
of  the  tunica  vaginalis  could,  in  its  earlier 
stages,  be  mistaken  for  hernia :  it  commences 
below  and  increases  in  an  upward  direction, 
while  a  hernia  proceeds  from  above  downwards; 
and  at  first  in  cases  of  hydrocele,  the  ring,  the 
cord,  and  all  these  parts  can  be  accurately  felt. 
As  the  disease  proceeds  and  the  water  reaches 
the  ring,  a  diagnosis  is  not  so  easy;  still  in 
almost  every  case  of  rupture  the  testis  and  the 
cord,  particularly  the  former,  can  be  easily  felt 
lying  behind  and  at  the  bottom  of  the  tumour, 
which  is  not  the  case  in  hydrocele.  Besides, 
hydrocele  is  lighter  as  to  weight ;  it  gives  a 
sensation  of  fluctuation  to  the  touch  ;  it  never 
exhibits  that  soft  doughy  character  that  belongs 
to  omental  hernia  :  moreover  it  is  diaphanous, 
and  the  light  of  a  candle  can  be  seen  through 
it,  if  the  tumour  is  examined  in  a  darkened 
room. 

A  collection  of  water  within  the  sheath  of 
the  cord  must,  I  should  think,  be  rather  an 
infrequent  occurrence ;  at  least  it  has  not 
fallen  to  my  lot  to  meet  with  many  examples 
of  it.  Still  the  practitioner  must  be  aware  of 
the  possibility  of  the  disease,  and  that  both 
from  the  nature  of  the  accident  that  occasions 
it,  and  many  of  the  accompanying  symptoms,  it 
may  very  readily  be  mistaken  for  hernia.  A 
young  man  fell  with  his  groin  against  the  edge 
of  a  tub,  and  in  an  incredibly  short  space  of 
time  afterwards  a  colourless  elastic  tumour 
appeared  in  the  usual   situation   of  hernia. 

*  Colles,  op.  citat. 

t  Scarpa,  op.  citat.  p.  235. 


HERNIA. 


7.55 


lie  was  admitted  into  the  Meath  Hospital 
under  the  care  of  the  late  Mr.  Hewson,  and 
though  some  years  have  now  elapsed  I  can 
well  recollect  the  variety  of  opinions  pronounced 
upon  it.  It  could  be  partially  pushed  up,  but 
re-appeared  instantly  on  the  pressure  being  re- 
moved :  it  was  slightly  influenced  by  coughing, 
and  it  was  extremely  tender  to  the  touch.  As 
the  patient  was  not  confined  in  the  bowels,  and 
in  fact  there  was  no  urgency  of  symptom,  no 
active  treatment  was  adopted,  and  the  tumour 
gradually  disappeared.  It  had  probably  been 
an  effusion  of  fluid  into  the  sheath  of  the  cord. 
The  manner  in  which  these  diseases  are  said  to 
be  capable  of  discrimination  is  as  follows.  Let 
the  tumour  be  pushed  up  if  possible,  and  the 
finger  of  the  operator  still  be  pressed  against 
the  ring:  if  it  is  a  hernia,  such  pressure  will  be 
sufficient  to  prevent  a  re-descent ;  but  if  it  is 
only  a  fluid,  it  will  insinuate  itself  by  the  side 
of  the  finger  and  the  tumour  shortly  re-appear. 
Scarpa*  denies  the  sufficiency  of  this  test  in 
cases  of  omental  hernia  of  small  size,  when 
situated  so  high  up  as  to  occupy  and  dilate  the 
inguinal  ring,  and  asserts  that  he  had  repeatedly 
observed  omental  inguinal  hernia  of  a  cylin- 
drical form,  which,  when  scarcely  returned,  re- 
appeared again  as  before  without  the  patient 
having  changed  his  posture  or  made  the  slight- 
est exertion  ;  and  in  like  manner  hydroceles  of 
the  spermatic  cord,  which,  when  pushed  beyond 
the  ring,  remained  there  as  long  as  the  patient 
kept  himself  in  the  supine  posture  without 
making  an  exertion.  He  seems  to  rely  more 
on  the  difference  of  consistence  and  regularity 
of  surface  in  the  two  tumours,  and  on  the  cir- 
cumstance of  the  hydrocele  being  always  broader 
inferiorly,  contrary  to  what  is  observed  in 
omental  hernia. 

A  varicose  enlargement  of  the  spermatic  vein 
is  not  easily  confounded  with  hernia,  unless  it 
has  increased  to  such  a  size  as  nearly  to  occupy 
that  side  of  the  scrotum  :  it  is  longer  in  pro- 
portion to  the  diameter  of  the  tumour  than 
hernia  usually  is,  and  its  surface  is  hard,  knotty, 
and  uneven.f  These  circumstances,  however, 
are  not  sufficient  to  remove  all  obscurity,  and  a 
farther  investigation  must  be  made  by  placing 
the  patient  in  the  horizontal  position  and  endea- 
vouring to  empty  the  vessel ;  then  let  him 
stand  up  whilst  firm  and  accurate  pressure  is 
maintained  upon  the  ring.  If  it  is  a  hernia, 
the  tumour  will  not  re-appear;  but  if  varicocele, 
it  will  return  as  speedily  or  perhaps  more  so 
than  if  no  pressure  had  been  made.  Mr. 
CollesJ  mentions  that  a  varicose  state  of  the 
cord  may  be  combined  with  hernia,  throwing 
great  obscurity  on  the  nature  of  the  disease, 
and  for  obvious  reasons  increasing  the  diffi- 
culty of  its  management. 

Inguinal  hernia  by  direct  descent. — I  now 

*  Op.  citat.  p.  98. 

t  These  symptoms  are  not  certainly  cliaracte" 
rislic  of  varicocele.  There  is  a  preparation  in  the 
Museum  of  Park  Street  taken  from  a  man  who 
exhibited  them  all  during  life.  His  disease  was  an 
enlarged,  knotted,  and  contorted  condition  of  the 
vessels  of  the  cord, 

\  Op.  citat. 


proceed  to  offer  a  few  remarks  on  the  other 
form  of  inguinal  hernia, — that  by  direct  descent,* 
which  occurs  when,  instead  of  passing  through 
the  canal,  the  protruded  viscus  is  pushed  out 
immediately  behind  the  situation  of  the  ex- 
ternal ring,  through  which  it  passes  directly. 
The  inferior  part  of  the  inguinal  canal  is  the 
weakest  of  all  the  parietes  of  the  abdomen. 
Externally,  independent  of  the  external  oblique 
muscle,  it  is  protected  as  far  as  the  external 
third  or  half  of  Poupart's  ligament  by  the 
fleshy  fibres  of  the  internal  oblique  and  trans* 
versalis  muscles,  and  by  the  fascia  transversal  is, 
which  is  dense  and  strong  in  this  situation,  but 
becomes  gradually  weaker  internally,  and  is 
nearly  lost  before  it  reaches  the  mesial  line. 
More  internally  it  is  supported  by  the  conjoined 
tendon  of  these  muscles,  but  as  it  arches  over 
the  spermatic  cord  that  portion  of  the  peri- 
toneal cavity  which  corresponds  with  the  inferior 
and  posterior  part  of  the  inguinal  canal  must 
depend  on  the  fascia  transvers.alis  alone,  now 
becoming  weaker  and  less  capable  of  resist- 
ance. More  internally  still,  and  immediately 
behind  the  external  ring,  this  region  is  best 
supported,  and  there  are  many  natural  obstacles 
to  the  production  of  hernia  in  this  situation. 
Besides  the  fasciae  already  mentioned  as  tending 
to  prevent  the  separation  of  one  pillar  of  the 
ring  from  the  other,  and  thereby  offer  an  ob- 
stacle to  the  passage  of  any  viscus  through  it, 
there  is  anotherf  of  a  triangular  shape  arising 
by  a  pretty  broad  base  from  the  crest  of  the 
pubis,  and  inserted  into  the  lineaalba  for  about 
an  inch  or  an  inch  and  a  quarter.  It  lies 
behind  the  tendon  of  the  external  oblique,  and 
before  that  of  the  internal  oblique  and  trans- 
versalis,  which  latter  it  strengthens  materially, 
and  its  external  edge  contributes  to  close  up  a 
part  of  the  external  ring.  The  edge  of  the 
rectus  muscle  extends  itself  laterally  sufficiently 
far  to  occupy  one-half  or  one-third  of  the  space 
behind  the  external  ring,  and  moreover  here  the 
conjoined  tendon  is  particularly  strong.  Not- 
withstanding these  supports,  this  part  is  weak  ; 
and  yet  when  a  hernia  occurs  here,  it  is  not  in 
consequence  of  yielding  or  stretching,  but  be- 
cause the  conjoined  tendon  actually  undergoes 
laceration. 

The  causes  of  this  hernia  are  said  to  be  three- 
fold :J  an  unnatural  weakness  of  the  conjoined 
tendon  ;  its  absence  altogether  in  consequence 
of  malformation  ;  and  its  being  ruptured  by 
direct  violence.  Of  these,  the  second  is  not 
likely  to  occur,  and  an  example  of  it  had  not 
been  met  with  by  Sir  A.  Cooper  at  the  time  of 
the  publication  of  his  work  :  the  other  two  in 
effect  amount  nearly  to  the  same  thing,  or  at 
least  stand  towards  each  other  in  the  relation  of 
a  predisposing  to  an  immediately  exciting 
cause. 

*  The  internal  inguinal  hernia  of  Hasselbach, 
Jules  Cloquet,  and  Velpeau  :  hernia  on  the  inner 
side  of  the  epigastric  artery  of  Sir  A.  Cooper,  and 
a  combination  of  ventral  and  inguinal  hernia  ac- 
cording to  Scarpa. 

f  This  is  frequently  termed  Colles's  fascia,  having 
been  first  accurately  described  by  that  writer, 

\  Cooper,  p.  51. 

3  D  2 


756 


HERNIA. 


The  hernia  by  direct  descent  is  distinguished 
from  the  oblique,  1st,  by  the  appearance  of  the 
groin,  the  apex  of  the  tumour  being  at  the 
situation  of  the  external  ring,  and  there  being 
no  enlargement  whatever  in  the  direction  of  the 
inguinal  canal  :  this  diagnostic,  however,  has 
been  found  fallacious,  for  in  old  oblique  hernia 
the  internal  ring  is  dragged  down  and  made  to 
approach  the  external  so  as  to  appear  to  form 
one  continuous  opening.    Nor  is  it  easy  to 
point  out  the  difference  even  in  dissection  ex- 
cept by  the  position  of  the  epigastric  artery, 
which  in  case  of  oblique  descent  always  lies  to 
the  pubic  side  of  the  neck  of  the  sac.  The 
neck  in  some  of  these  cases  appears  to  be 
arched  over  and  strongly  constricted  by  the 
superior  portion  of  the  ruptured  conjoined 
tendon,  which  in  these  cases  is  more  than 
usually  developed,  and  (as  it  were)  in  a  state  of 
hypertrophy.    It  was  probably  this  appearance 
that  led  to  a  belief  that  strangulation  was  occa- 
sionally produced  by  the  action  of  these  mus- 
cles.    2nd,  By  the  relative  position  of  the 
tumour  with  respect  to  the  different  structures 
composing  the  cord.    The  cremaster  muscle  in 
any  hernia  cannot  be  felt,  but  it  occupies  nearly 
its  usual  position  in  this,  being  spread  out  like 
a  fascia  in  front  of  it,  but  rather  towards  its 
outside.    The  spermatic  cord  properly  so  called 
passes  on  its  external  rather  than  on  its  pos- 
terior side;  and  although  all  its  constituent 
vessels  may  be  separated  in  this  as  in  any  other 
species  of  large  and  old  hernia?,  yet  generally 
there  is  less  divarication  in  this,  and  the  parts 
lie  together  more  compactly.     3rd,  "  This 
tumour  differs  from  the  common  bubonocele  in 
being  situated  nearer  the  penis."*    This  is  cer- 
tainly true  when  it  is  only  bubonocele;  but 
when  it  has  descended  into  the  scrotum,  the 
same  difficulty  that  has  been  noticed  as  apper- 
taining to  old  ruptures  must  also  obtain  here. 
In  applying  this  diagnostic  the  student  must 
recollect  that  the  internal  edges  of  both  hernia? 
are  equally  near  to  the  pubis  ;  it  is  by  looking 
to  the  external  border  of  the  neck  of  the  tumour 
that  he  can  render  the  test  available.    Scarpa f 
states  that  this  hernia  is  returned  without  being 
attended  by  the  gurgling  sound  :  this,  however, 
is  an  observation  perfectly  new  to  me,  and 
which  I  can  by  no  means  verify.    Lastly,  these 
herniae  appear  more  suddenly  and  attain  a  larger 
size  more  rapidly :  frequently  they  appear  as  scrotal 
ruptures  almost  from  the  earliest  period.  This, 
however,  is  still  an  uncertain  criterion,  and  in- 
deed with  the  assistance  of  all  these  circum- 
stances it  is  always  so  difficult  and  frequently 
so  utterly  impossible  to  establish  a  diagnosis, 
that  no  operation  should  be  undertaken  under 
the  conviction  of  the  disease  being  certainly  of 
one  form  or  of  the  other. 

This  rupture  should  present  to  the  anatomist 
the  same  number  of  layers  of  fascia  as  that  by 
the  oblique  descent,  the  fascia  transversalis  sup- 
plying the  place  of  that  given  off  from  the  edges 
of  the  internal  ring;  J  but  the  young  surgeon 

*  Cooper. 

t  Scarpa,  op.  citat.  p.  84. 

J  The  internal  spoul-like  fascia. 


should  be  cautioned  not  to  expect  the  same 
facilities  of  demonstration  in  the  living  subject 
that  he  possesses  in  the  dead.  In  the  former, 
the  operator  often  meets  with  layer  after  layer 
of  fascia,  numerous  beyond  his  expectation,  and 
to  which  he  can  give  no  name;  and  it  is  no  un- 
common circumstance  for  him  to  operate  on 
and  return  a  rupture  without  being  able  to  say 
of  what  nature  it  was — nay,  even  as  to  its  being 
inguinal  or  crural. 

Crural  or  femoral  hernia  takes  place 
at  the  superior  and  internal  part  of  the  thigh, 
below  the  fold  of  the  groin  ;  the  intestine  pass- 
ing out  of  the  abdomen  behind  Pou part's  liga- 
ment, between  it  and  the  transverse  ramus  of 
the  pubis,  through  an  aperture  that  has  been 
termed  the  crural  or  femoral  ring.  A  know- 
ledge of  the  constitution,  size,  and  boundaries 
of  this  ring  must  be  of  the  last  importance  to 
the  practical  surgeon,  and  accordingly  no  part 
of  the  body  has  been  examined  with  more 
minute  attention  ;  yet  if  by  these  labours  ana- 
tomy has  gained  in  accuracy  of  information  and 
very  diffuse  description,  still  the  student  is  not 
much  the  better  for  it,  inasmuch  as  almost 
every  anatomist  has  adopted  views  peculiar  to 
himself,  and  thus  in  the  details  a  degree  of  con- 
fusion has  been  produced  that  is  extremely  em- 
barrassing to  the  beginner.  I  shall,  therefore, 
avail  myself  as  little  as  possible  of  authorities, 
and  endeavour  to  describe  these  parts  as  they 
appear  upon  dissection,  commencing  from 
within,  which  is  perhaps  the  best  mode  of 
studying  the  anatomy  of  every  species  of 
hernia. 

The  distance  between  the  anterior  superior 
spinous  process  of  the  ileum  and  the  angle  of 
the  crest  of  the  pubis  is  in  the  well-formed 
female  about  five  and  a  half  inches  in  length, 
along  which  space  Poupart's  ligament  is 
stretched  like  a  bow-string  from  point  to  point. 
The  distance  from  the  ligament  thus  extended, 
backwards  to  the  edges  of  the  ileum  and  pubis 
forming  the  border  of  the  pelvis,  varies  accord- 
ing to  the  elevations  and  depressions  of  these 
bones;  but  the  entire  forms  a  very  considerable 
space,  which  is,  however,  in  general  so  well 
filled  up  that  unless  under  peculiar  circum- 
stances this  region  affords  sufficient  support 
and  protection  to  the  viscera  of  the  abdomen. 
On  examining  the  corresponding  peritoneal  sur- 
face within,  the  membrane  is  found  capable  of 
being  detruded  only  at  one  spot,  internal  to  the 
view,  and  about  an  inch  and  a  half  distant  from 
the  symphysis  pubis.  Here,  there  is  a  natural 
aperture  varying  in  size  in  different  subjects, 
into  which  the  finger  may  be  pushed  by  a  little 
violence,  and  a  small  artificial  hernial  sac  like 
a  thimble  be  thus  produced.  On  tearing  off 
the  peritoneum  it  is  easy  to  observe  the  dif- 
ferent arrangements  that  serve  to  support  and 
strengthen  this  region  of  the  abdomen. 

From  Poupart's  ligament  three  distinct  layers 
of  fascia  pass  off  in  different  directions.  The 
fascia  transversalis  has  been  already  described 
as  passing  upwards  on  the  front  of  the  abdomen, 
where  it  is  gradually  lost.  From  the  inferior 
and  posterior  part  of  the  arch  another  fascia 
passes,  at  first  downwards,  then  upwards  and 


HERNIA. 


757 


backwards,  to  expand  itself  over  the  iliacus 
internus  and  psoas  muscles  ;  and  it  is  therefore 
called  the  fascia  iliaca.  These  fasciae  are  per- 
fectly continuous  as  far  inwards  as  the  external 
border  of  the  artery,  and  form  a  smooth  and 
strong  membranous  wall  for  the  abdomen  in 
this  situation,  rather  attached  to  Poupart's  liga- 
ment than  coming  off  or  derived  from  it.* 
These  fasciae  separate  at  this  spot  and  unite 
again  between  the  artery  and  vein,  thus  forming 
a  sheath  for  the  former  vessel  :  in  like  manner 
a  separate  sheath  is  formed  for  the  vein,  when 
they  again  separate  and  leave  a  small  opening, 
which  is  the  crural  ring,  but  unite  before  they 
reach  Gimbernat's  ligament,  to  the  abdominal 
surface  of  which  they  give  an  investment,  but 
here  the  fibrous  structure  is  very  weak  and 
differs  little  in  appearance  from  cellular  mem- 
brane. These  fasciae  then  form  a  fiat,  broad 
funnel,  which  has  three  apertures  at  top,  and  the 
membranous  septa  are  of  the  greatest  use  in 
binding  the  anterior  and  posterior  faces  of  this 
fuunel  together  :  hence  a  hernia  cannot  escape 
through  in  company  with  the  artery  nor  with 
the  vein,  and  hence  also  the  vein  is  not  com- 
pressed nor  its  circulation  interfered  with,  even 
although  a.  hernia  close  to  it  is  in  a  state  of 
strangulation.  This  funnel  descends  on  the 
vessels,  to  which  it  becomes  firmly  attached,  at 
about  an  inch  and  a  half  below  Poupart's  liga- 
ment, and,  according  to  some  anatomists,  is 
there  reflected  up  again  on  the  vessels  forming 
a  cul-de-sac  or  bag.  I  thus  consider  the 
crural  ring  properly  so  called  to  be  an  aperture 
formed  by  a  deficiency  in  the  fascia  iliaca  and 
transversalis,  just  as  the  internal  inguinal  ring 
is  formed  in  the  latter  membrane  alone.  It  is 
occupied  by  a  loose  cellular  tissue,  and  in 
general  by  a  small  absorbent  gland. 

This  ring  is  of  a  different  size  in  different 
individuals ;  and  where  it  is  large,  the  person 
may  be  said  to  have  an  hereditary  or  congenital 
disposition  to  the  disease  ;  but  a  liability  to  it 
may  arise  from  accidental  circumstances  also. 
It  is  obvious  that  in  proportion  as  the  space 
beneath  the  crural  arch  is  well  filled,  and  the 
muscles  tense  and  plump,  the  aperture  at  the 
ring  must  be  small ;  also  that  it  will  be  larger 
according  to  the  greater  breadth  between  the 
spinous  process  and  the  pubis,  or  as  the  space 
under  the  crural  arch  is  deep.  Hence  it  may 
be  explained  why  this  kind  of  rupture  is  fre- 
quent amongst  women  who  have  borne  many 
children,  with  whom  the  parietes  of  the  abdo- 
men are  relaxed  ;  less  frequent  amongst  young 
and  healthy  unmarried  females,  and  scarcely 
known  amongst  men,  the  pelvis  of  the  male 
being  narrower,  and  his  muscle  better  developed 
by  use  and  exercise. 

The  crural  arch  or  Poupart's  ligament  is 

*  Their  importance  in  strengthening  this  part  of 
the  abdomen  is  proved  by  an  experiment  of  Mr. 
Colles.  "  Make  in  the  aponeurosis  which  covers 
the  iliac  muscle  an  opening  capable  of  admitting 
the  finger.  Pass  it  between  the  aponeurosis  and 
surface  of  the  muscle,  and  you  will  be  enabled,  with- 
out much  difficulty,  to  push  the  finger  under  Pou- 
part's ligament  down  to  the  fore  part  of  the  thigh." 
Colles,  op.  citat.  p.  68. 


nothing  more  than  the  inferior  pillar  of  the 
externa!  inguinal  ring,  and  is  (as  has  been  before 
stated)  inserted  into  the  crest  of  the  pubis  ;  but 
it  has  another  attachment  to  this  bone,  which, 
being  in  intimate  relation  with  femoral  hernia,  I 
have  delayed  the  description  of  until  now.  As 
the  ligament  approaches  the  pubis,  its  inferior 
edge  becomes  twisted  upwards  and  backwards 
towards  the  linea  ileo-pectinea,  into  which  it  is 
inserted  for  a  length  of  from  a  half  to  three 
quarters  of  an  inch.  Its  shape  is  triangular,  its 
posterior  attachment  being  somewhat  shorter 
than  its  anterior  ;  and  its  base,  which  has  its 
aspect  towards  the  vein,  is  somewhat  lunated. 
In  the  male  its  situation  corresponds  nearly 
with  the  external  inguinal  ring ;  and  the  sper- 
matic cord  rests  on  it  just  as  it  is  about  to  pass 
from  the  inguinal  canal. 

The  fibrous  funnel-like  sheath  already  des- 
cribed is  itself  lodged  within  a  cavity  which 
may  be  called  the  crural  canal,  and  is  thus 
formed.  The  fascia  lata  of  the  thigh  in  front 
has  two  origins,  one  from  the  whole  length  of 
Poupart's  ligament,  the  other  from  so  much  of 
the  linea  ileo-pectinea  as  gives  origin  to  the 
pectinalis  muscle,  and  from  the  ligament  of  the 
pubis.  This  latter  portion  having  passed  down 
the  thigh  unites  with  the  former  below  the  en- 
trance of  the  saphena  into  the  femoral  vein, 
below  which  point  they  form  one  continuous 
sheath  for  the  muscles  of  the  limb.  The  por- 
tion, however,  which  comes  from  Poupart's 
ligament  requires  more  attention.  At  first  it 
lies  completely  in  front  of  the  upper  part  of  the 
thigh,  and  of  course  leaves  a  triangular  space 
between  it  and  the  other  portion,  in  which  are 
lodged  the  funnel-shaped  fascial  sheath,  with 
its  contents,  the  artery  and  vein,  lymphatic 
vessels,  and  some  glands.  About  half  an  inch, 
or  in  some  subjects  a  little  more,  below  Pou- 
part's ligament  the  internal  portion  of  this  fascia 
appears  to  be  wanting,  leaving  the  vessels  un- 
covered by  it  as  far  down  as  the  point  of  union 
of  the  two  fasciae  :  I  say  appears  to  be  wanting, 
because  the  fascia  lata  is  really  continued  over 
this  space,  joins  the  pubic  portion  internally, 
and  sends  a  process  upwards  to  be  inserted 
into  the  linea  ileo-pectinea,  external  to  the 
lunated  edge  of  Gimbernat's  ligament,  and  be- 
tween it  and  the  edge  of  the  femoral  ring  ;  but 
it  is  here  so  thin  and  cellulated  that  it  is 
generally  removed  in  the  dissection.  When 
thus  disposed  of,  the  firm  portion  of  the  external 
fascia  lata,  as  it  passes  to  join  the  internal, 
assumes  a  lunated  form  above  and  below,  and 
thus  the  entire  apparent  deficiency  is  made  to 
appear  of  an  oval  figure,  the  edges  of  which  are 
crescentic,  and  which  have  been  called  by  the 
different  names  of  Iley's  ligament,  Burns'  liga- 
ment, and  the  crescentic  edge  of  the  fascia  lata. 
A  finger  pushed  from  above  through  the  crural 
ring  will  easily  feel  the  superior  margin  of  this 
aperture,  and  its  influence  on  hernia  in  this 
situation  will  soon  be  made  apparent.  The 
femoral  or  crural  canal  then  is  from  one-half  to 
three-fourths  of  an  inch  in  length,  and  is  formed 
by  the  fascia  lata  :  it  is  bounded  above,  anteriorly 
by  Poupart's  ligament  and  posteriorly  by  the  linea 
ileo-pectinea;  below,  anteriorly  by  the  crescentic 


763 


HERNIA. 


edge  of  the  fascia  lata  or  I  ley's  ligament,  and 
posteriorly  by  its  pubic  portion  :  both  externally 
and  internally  it  is  bounded  by  the  junction  of 
these  two  portions  of  fascia.  Gimbernat's  liga- 
ment, which  is  usually  described  as  forming  the 
internal  boundary  of  the  crural  ring,  rarely  fills 
up  more  than  half  the  space  between  the  crest 
of  the  pubis  and  the  femoral  vein.  This  canal, 
as  being  composed  of  fascia,  is  firm,  and  un- 
yielding :  it  cannot  be  influenced  by  the  actions 
of  any  muscle  in  the  neighbourhood,  nor  even 
so  much  as  is  generally  supposed  by  the  posi- 
tion of  the  limb.  It  should  follow  from  this 
constitution  of  parts  that  any  hernia  thus  re- 
strained should  forcibly  compress  the  vein  and 
artery  before  it  suffered  strangulation  itself,  and 
so  it  would  if  the  protrusion  had  relation  to 
this  canal  alone,  and  was  not  contained  within 
its  own  proper  portion  of  the  funnel-shaped 
sheath  already  described. 

The  neck  of  the  sac  of  a  femoral  hernia,  then, 
has  behind  it  the  fascia  iliaca  and  the  ligamento- 
cartilaginous  material  that  covers  the  sharp  edge 
of  the  linea  ileo-pectinea  :  internally  it  has  the 
junction  of  the  fascia  iliaca  and  transversalis, 
the  attachment  of  the  fascia  lata  to  the  linea 
ileo-pectinea,  and  Gimbernat's  ligament;  inter- 
nally it  must  also  have  the  spermatic  cord  in 
the  male  and  the  round  ligament  in  the  female; 
anteriorly  it  has  the  fascia  transversalis  and 
Pouparl's  ligament,  and  immediately  above  the 
neck  and  in  close  contact  with  it  is  the  sper- 
matic cord,  of  course  including  the  spermatic 
artery  :  externally  is  the  membranous  slip  in- 
terposed between  it  and  the  femoral  vein.  The 
epigastric  artery  is  also  external  to  it,  but 
although  this  vessel  is  somewhat  irregular  both 
in  origin  and  position,  yet  the  full  breadth  of 
the  vein  must  be  always  interposed  between  it 
and  the  neck  of  the  sac.  But  there  is  an 
irregular  vascular  distribution  that  must  be 
borne  in  mind.  In  a  great  number  of  subjects 
(perhaps  one  out  of  every  four  or  five)  the 
obturator  artery,  instead  of  coming  oft'  from  the 
internal  iliac,  arises  by  a  common  trunk  along 
with  the  epigastric,  which  it  soon  leaves,  and 
passing  downwards  and  inwards  crosses  the 
superior  aperture  of  the  femoral  canal  before  it 
dips  into  the  pelvis  to  reach  the  obturator 
Foramen.  In  this  course  it  sometimes  passes 
the  border  of  the  canal  posteriorly,  but  much 
more  frequently  in  front;  and  in  this  latter  case, 
if  a  hernia  existed,  the  vessel  would  embrace 
two-thirds  of  the  circle  of  the  displaced  peri- 
toneum close  to  and  immediately  above  the 
neck.  It  appears,  then,  from  these  anatomical 
relations  that  in  all  subjects  a  considerable 
degree  of  danger  may  arise  from  too  free  and 
unguarded  a  use  of  the  knife  in  operation — a 
danger  that  is  necessarily  enhanced  in  the  male 
subject :  indeed  in  consequence  of  the  risk  of 
haemorrhage  Scarpa  seemed  disposed  to  trust  to 
dilatation  and  laceration  ot  Poupart's  ligament 
for  relieving  the  stricture,  and  where  these 
means  were  insufficient  he  recommended  a  new 
and  particular  direction  to  be  given  to  the 
incision.  But  from  caieful  dissection  and  ex- 
amination of  these  parts  I  am  disposed  to 
believe  there  is  always  sufficient  space  to  free  a 


stricture  without  endangering  either  the  sper- 
matic or  the  irregular  obturator  artery.  It  must 
be  recollected  that  if  the  intestine  is  sufficiently 
liberated  to  permit  the  passage  of  gas  through 
the  immediate  seat  of  the  stricture,  its  return  is 
perfectly  practicable,  and  a  very  small  incision 
will  be  sufficient  to  accomplish  this.  Now 
these  vessels  lie,  not  on  the  neck  of  the  sac,  but 
above  it  ;  and  there  is  quite  space  enough  to  set 
the  stricture  free  without  interfering  with  them  : 
when  they  are  wounded,  it  is  in  consequence  of 
the  introduction  of  the  cutting  edge  of  the 
bistoury  too  far  within  the  stricture. 

When  a  portion  of  intestine  has  escaped 
through  the  femoral  ring,  (and  by  reason  of  the 
small  size  of  the  aperture  hernia  here  are 
seldom  large,)  it  lies  at  first  within  the  crural 
canal,  where  it  is  restricted  by  the  fascia  lata, 
and  its  existence  recognized  with  difficulty.  Jt 
has  happened  that  patients  have  perished  from 
the  incarceration  of  a  small  fold  or  knuckle  of 
intestine  without  the  circumstance  ever  having 
been  discovered  during  life.  But  after  it  has 
passed  the  crescentic  edge  of  Key's  ligament, 
and  is  relieved  from  the  pressure  of  the  fascia, 
it  comes  forward,  and  if  it  increases  farther,  its 
direction  is  rather  inwards  and  upwards,  so 
that  it  may  assume  the  position  of  an  inguinal 
hernia  to  the  extent  of  being  mistaken  for  it. 
Having  proceeded  so  far,  the  hernial  sac  has 
assumed  somewhat  of  the  form  of  an  arch  :  it 
has  passed,  first  downwards  through  the 
femoral  canal,  then  forwards  under  the  sharp 
edge  of  the  fascia  lata,  either  passing  through 
the  weak  cellular  portion  of  it  or  pushing  it 
before,  and  then  upwards  and  inwards  in  front. 
The  hollow  of  this  arch  looks  upwards,  and  is 
occupied  by  the  crescentic  edge  of  Hey's  liga- 
ment. Perhaps  this  particular  position  of  the 
hernia,  as  well  as  the  extreme  straitness  and  un- 
yielding nature  of  the  crural  canal,  has  con- 
tributed to  the  frequency  of  strangulation  to 
which  this  form  of  hernia  is  liable. 

When  a  person  stands  erect  and  without 
exertion,  Poupart's  ligament  forms  nearly  a 
direct  line  between  the  anterior  superior  spinous 
process  of  the  ileum  and  the  crest  of  the  pubis, 
and  all  the  fasciae  connected  to  it  are  in  their 
natural  state  and  sufficiently  relaxed  ;  but  if  the 
thigh  is  strongly  extended  or  the  body  bent 
backward,  the  ligament  then  becomes  tense  and 
is  arched  backward  toward  the  thigh.  The 
effect  of  the  general  tension  of  the  limb  in  this 
position  would  be  to  convert  the  arch  formed 
by  the  hernia  into  an  angle,  against  the  hollow 
of  which  the  edge  of  Hey's  ligament  would  be 
firmly  compressed,  and  a  sufficient  degree  of 
resistance  thus  created  to  the  return  of  the 
venous  blood  to  produce  a  congested  condition 
of  the  viscus.  The  operation  of  such  a  cause 
as  this  can  hardly  be  considered  as  permanent, 
but  the  mischief  once  commenced  is  not  easily 
controlled,  and  an  intestine  might  soon  be 
placed  in  such  a  condition  as  to  render  incar- 
ceration at  the  ring  inevitable. 

The  situations  at  which  crural  hernia  may 
be  strangulated  have  not  been  satisfactorily 
described,  although  there  is  no  subject  on  which 
more  anatomical  labour  has  been  bestowed.  If 


HERNIA. 


759 


I  was  to  speak  from  my  own  experience  alone, 
I  should  say  that  though  the  hernia  itself  is 
superficial,  the  seat  of  the  strangulation  is 
always  deep — somewhere  at  or  in  the  imme- 
diate neighbourhood  of  the  neck  of  the  sac.  I 
found  the  opinion  partly  on  the  dissection  of 
subjects  that  had  died  of  the  disease,  but  more 
particularly  on  the  phenomena  I  have  observed 
during  the  progress  of  an  operation  on  the 
living:  still  the  experience  of  one  individual 
can  scarcely  ever  be  sufficient  to  establish  a 
great  pathological  principle,  and  there  is  autho- 
rity that  cannot  be  questioned  for  believing 
that  crural  hernia  is  frequently  strictured  at  a 
far  less  depth  from  the  surface.  Besides  the 
neck  of  the  sac,  by  which  this  hernia  is  con- 
fessedly strictured  in  very  many  cases,  Sir  A. 
Cooper  places  the  seat  of  strangulation,  first  in 
the  crural  sheath  and  semilunar  or  lunated 
edge  of  the  fascia  lata,  and  secondly  in  the 
posterior  edge  of  the  fascia  lata.*  Mr.  Colles 
says  that  the  neck  or  constricted  part  of  crural 
hernia  does  not  always  appear  at  the  same 
depth  from  the  surface,  and  explains  the  cir- 
cumstance thus  :  "The  hernia  having  descended 
into  the  femoral  sheath,  it  escapes  through  one 
of  those  apertures  in  it  for  transmitting  the 
lymphatic  vessels,  and  also  passes  through  a 
corresponding  opening  in  the  iliac  portion  of 
the  fascia  lata.  As  it  passes  through  a  small 
aperture  in  each  of  these  parts  at  nearly  the 
same  spot,  it  must  there  be  liable  to  great  con- 
striction ;  for  these  two  layers  of  fascia  will  be 
compressed  together,  and  thus  their  strength 
and  resistance  be  considerably  augmented. 
Hence  we  should  find  the  seat  of  stricture  in 
strangulated  femoral  hernia  frequently  to  be  at 
some  distance  below  and  to  the  pubic  side  of 
the  crural  ring."f  The  descriptions  of  Hey  and 
Burns  I  cannot  profess  clearly  to  understand, 
and  I  fear  they  were  taken  rather  from  sound 
subjects  than  from  those  in  which  herriiae  were 
actually  present.  Scarpa  does  not  distinctly 
point  out  the  anatomy  of  the  seat  of  stricture, 
but  from  the  general  bearing  of  his  descriptions, 
and  above  all  from  the  anxiety  he  expresses 
relative  to  the  danger  of  wounding  the  sper- 
matic artery  in  operation,  which  vessel,  if  pre- 
sent, must  lie  close  to  the  neck  of  the  sac,  I 
would  hazard  an  opinion  that  he  believed  the 
seat  of  strangulation  to  be  always  deeply 
seated. 

In  dissecting  this  rupture  from  without,  or 
in  operating  upon  it  in  the  living,  it  will  be 
found  to  lie  at  a  different  depth  from  the  sur- 
face, and  to  possess  variety  in  the  number  of 
fascial  coverings  according  to  its  position  with 
reference  to  the  parts  already  described.  Thus 
it  may  be  placed  within  the  crural  canal, 
within  that  triangular  space  formed  by  the 
fascia  lata ;  or  having  passed  beyond  its  inferior 
opening  or  falciform  edge,  it  may  present 
more  superficially.  In  the  former  case,  after 
the  division  of  the  common  integuments,  the 
skin  and  fat,  the  superficial  fascia  is  exposed 
and  may  consist  of  many  layers — at  all  events 

*  Cooper  on  Hernia,  part  ii  p.  14. 
t  Colics'  Surgical  Anatomy,  p.  77. 


of  two :  next  is  the  dense  and  resisting  fascia 
lata  of  the  thigh  ;  and  deeper  still,  the  funnel- 
shaped  fascia  in  which  the  crural  ring  is  situated. 
Between  this  latter  and  the  sac  another  fascia 
has  been  described  under  the  name  of  the  fascia 
propria,  which  may  be  supposed  to  be  formed 
by  a  condensation  of  that  cellular  tissue  already 
described  as  occupying  the  crural  ring ;  but  I 
have  never  been  able  to  satisfy  myself  as  to  the 
existence  of  this  as  a  distinct  membrane,  and  I 
must  again  caution  the  young  operator  not  to 
expect  to  meet  with  laminse  of  fascia  as  de- 
scribed or  demonstrated  by  the  anatomist.  A 
dexterous  and  careful  dissector  may  make  al- 
most as  many  layers  of  fascia  as  he  pleases. 

After  it  has  passed  the  inferior  border  of  the 
crural  canal  and  appeared  more  externally,  the 
coverings  of  fascia  to  be  expected  must  depend 
on  the  view  taken  of  the  anatomy  of  this  part. 
If  it  is  believed  that  the  hernia  having  cleared 
this  point  merely  swells  out  on  being  relieved 
from  the  pressure,  without  passing  or  pushing 
through  any  of  the  superincumbent  structures, 
then  in  order  to  come  down  upon  the  sac  it 
would  be  necessary  to  divide  the  skin  and 
cellular  tissue,  the  different  lamina?  of  the  fascia 
superficialis,  the  cribriform  portion  of  the  fascia 
lata,  the  anterior  portion  of  the  funnel-shaped 
fascia,  and  the  fascia  propria.  If,  on  the  other 
hand,  it  is  supposed  that  the  hernia  has  escaped 
through  one  of  the  openings  in  the  femoral 
sheath,  and  a  corresponding  one  in  the  iliac 
portion  of  the  fascia  lata,  it  will  lie  more  super- 
ficial by  the  absence  of  these  investments.  In 
either  case  the  last  layer  of  fascia  most  adja- 
cent to  the  sac  is  almost  always  remarkable  for 
density  and  strength. 

The  general  symptoms  of  this  affection  are 
the  same  with  those  of  inguinal,  such  as  the 
appearance  of  the  tumour,  its  diminution  or 
disappearance  in  the  recumbent  position,  and 
the  impulse  imparted  to  it  by  coughing,  sneez- 
ing, &c. :  its  peculiar  symptoms  are  explicable 
by  its  anatomical  relations.  1.  The  crural 
hernia  is  generally  small  and  its  increase  slow  : 
the  size  of  the  ring  and  the  compression  ex- 
ercised on  it  by  so  many  superincumbent 
layers  of  fascia  will  be  sufficient  to  account  for 
this,  and  also  will  shew  why  this  rupture  is 
almost  always  painful,  and  why  position  has  so 
much  effect  on  it,  relief  being  constantly  ob- 
tained by  bending  the  thigh  on  the  pelvis  and 
rotating  the  limb  inwards.  2.  The  peculiar 
manner  of  growth,  its  first  passing  downwards, 
then  forwards,  and  then  upwards  and  inwards, 
is  caused  by  the  attachment  of  the  funnel-like 
fascia  to  the  vessels  at  the  superior  part  of  the 
thigh,  and  by  that  of  the  fascia  supeificialis 
to  the  fascia  lata  near  the  entrance  of  the 
saphena  vein  ;  thus  its  shape  is  never  pyramidal 
like  that  of  inguinal  ;  it  is  globular  or  oval,  and 
its  longest  diameter  is  transverse.  3.  I  have 
already  mentioned  its  prevalence  amongst 
females  advanced  in  life. 

As  the  testicle  is  more  subject  to  disease 
than  any  structure  at  the  top  of  the  thigh,  there 
are  more  affections  with  which  scrotal  hernia 
may  be  confounded;  but  on  the  other  hand, 
when  a  doubt  arises  on  the  subject  of  crural 


760 


HERNIA, 


hernia,  the  diagnosis  is  vastly  more  difficult,  and 
often  the  surgeon  has  to  be  guided  by  the  gene- 
ral symptoms  of  peritoneal  inflammation  rather 
than  by  the  results  of  local  examination,  how- 
ever carefully  performed.  Mr.  Colles*  states 
that  "this  species  of  hernia  is  liable  to  stran- 
gulation even  before  it  can  be  felt  externally," 
— an  observation  I  was  enabled  to  verify  a  few 
months  since  in  a  case  where  a  very  small 
knuckle  of  intestine  had  not  passed  the  inferior 
aperture  of  the  femoral  canal,  but  was  lodged 
in  an  absorbent  gland,  which  seemed  to  have 
been  hollowed  out  to  receive  it.f  But  the 
hernia  may  be  much  larger  and  still  not  disco- 
verable in  consequence  of  some  unfortunate 
complication  :  I  have  seen  a  case  of  incarce- 
rated hernia  J  in  which  an  abscess  was  seated 
at  the  superior  part  of  the  thigh  immediately 
in  front  of  the  sac ;  and  after  the  pus  had  been 
evacuated,  some  time  elapsed  before  decisive 
symptoms  pointed  out  the  existence  of  the 
more  formidable  disease  behind.  There  is, 
in  the  Museum  in  Park-street,  a  preparation 
exhibiting  a  fatty  tumour  growing  on  the  exter- 
nal surface  of  a  hernial  sac.  The  patient  from 
whom  it  was  taken  was  the  subject  of  opera- 
tion, and  after  the  integuments  and  fascia  had 
been  divided  and  this  tumour  presented,  some 
doubts  were  at  first  entertained  as  to  the  pre- 
sence of  a  hernia  beneath  it;  but  on  careful 
examination  the  operator  discovered  the  hernial 
tumour,  and  cutting  cautiously  through  the 
other,  opened  the  sac,  in  which  a  knuckle  of 
intestine  was  found  incarcerated.  The  opera- 
tion was  successful,  and  the  patient  recovered. 
"  In  many  instances,"  says  Mr.  Colles,  "  the 
difficulty  of  discriminating  the  disease  is  consi- 
derably increased  by  an  enlarged  lymphatic 
g'and  lying  anterior  to  a  very  small  hernia." 

Perhaps  there  are  no  two  affections  more 
liable  to  be  mistaken  for  each  other  than  crural 
hernia  and  an  enlarged  lymphatic  gland;  and 
however  apparently  distinct  the  two  affections 
may  be,  and  however  easy  it  may  seem  to  form 
a  diagnosis  in  theory,  still  the  best  surgeons 
speak  of  the  difficulty  of  discriminating  between 
them,  and  many  acknowledge  having  fallen 
into  the  error  themselves.  It  has  happened 
that  a  patient  has  had  a  hernia  on  one  side  and 
an  enlarged  gland  on  the  other,  and  when 
symptoms  of  strangulation  became  urgent,  it 
was  the  gland  that  was  considered  to  be  the 
most  pressing, and  it  was  selected  for  the  opera- 
tion. I  recollect  two  cases  which  occurred 
nearly  at  the  same  time  ;  one  in  which  there 
was  a  very  minute  hernia  at  the  left  groin, 
which  had  been  regarded  as  a  swelled  gland, 
and  the  patient  died  of  the  effects  of  its  stran- 
gulation ;  the  other  a  case  of  pure  peritoneal 
inflammation,  in  which  the  patient  happened  to 
have  a  swollen  gland  in  the  groin,  which  was 
actually  cut  down  upon  and  exposed,  but  the 
operation  did  not  much  injury,  for  the  patient 

*  Op.  citat.  p.  83. 

t  This  curious  case  occurred  in  the  Meath  Hospi- 
tal in  the  summer  of  1835. 

|  I  use  this  term  in  the  sense  hitherto  employed, 
not  implying  perfect  strangulation. 


subsequently  recovered.  It  has  been  said  that 
a  diagnosis  can  be  established  by  attention  to 
the  following  circumstances.  The  hernia  fol- 
lows on  some  sudden  exertion,  on  a  blow  or  a 
fall,  and  appears  suddenly  and  at  once ; 
whereas  the  gland  in  the  commencement  is 
very  small,  perhaps  like  a  moveable  kernel, 
and  increases  slowly  and  by  degrees.  Besides, 
this  diagnostic  will  be  greatly  assisted  if  there 
is  a  chancre  or  other  sore  to  account  for  the  irri- 
tation and  inflammation  of  the  gland;  but  on 
the  other  hand  the  hernia  does  not  always- 
assume  its  given  size  at  once,  it  is  often 
so  small  at  the  beginning  that  the  patient  is  not 
aware  of  its  existence,  and  so  far  from  appear- 
ing suddenly  after  a  violent  exertion  it  may 
have  been  present  for  months  without  being 
perceived.  The  hernia  receives  an  impulse 
from  coughing  or  sneezing,  and  retires  or  be- 
comes smaller  in  the  recumbent  posture,  which 
are  not  observed  to  happen  with  the  gland  ;  but 
then  an  enlarged  gland  may  be  complicated 
with  a  hernia,  and  the  symptoms  so  mixed  and 
confused  that  a  diagnosis  may  be  very  difficult. 
It  is  said  that  a  gland  maybe  moved  about  and 
withdrawn  from  its  situation  in  a  slight  degree, 
and  if  it  can  there  is  no  great  danger  of  mis- 
taking it ;  but  when  it  has  arrived  at  the  size  or 
occupies  the  place  which  could  make  it  resem- 
ble a  hernia,  then  it  does  not  admit  of  being 
moved  under  the  fascia,  and  the  diagnosis  is 
almost  impossible.  Fortunately,  a  crural  hernia 
does  not  often  consist  of  omentum,  but  when  it 
does  there  is  nothing  more  likely  to  exhibit  the 
characters  of  a  gland  in  a  state  of  chronic  dis- 
ease, and  I  know  not  how  the  two  cases  can  be 
accurately  distinguished.  Here  the  physical 
evidence  derived  from  a  gentle  percussion  (as 
already  noticed)  is  utterly  and  completely 
valueless. 

Lumbar  or  psoas  abscess  is  another  affection 
that  may  be  confounded  with  femoral  hernia, 
and  Mr.  Colles  states  that  he  had  known  the 
mistake  to  have  been  committed.  These  diseases 
resemble  each  other  in  the  following  circum- 
stances. Both  present  very  nearly  in  the  same 
situation  at  the  bend  of  the  groin,  are  firm  and 
elastic;  coughing  gives  to  each  the  same  or  a 
similar  impulse;  and  there  are  cases  on  record 
in  which  psoas  abscess  disappeared  under  pres- 
sure or  by  the  patient  assuming  the  recumbent 
posture.  Yet  I  think  the  two  cases  not  very 
difficult  of  distinction.  Psoas  abscess  is  a  dis- 
ease of  youth;  it  does  not  often  occur  in  the 
adult  except  as  a  critical  abscess  after  fever,  or 
in  connexion  with  caries  and  curvature  of  the 
spine,  in  either  of  which  cases  the  collateral 
circumstances  will  point  itout ;  whereas  femoral 
hernia  is  the  disease  of  married  women,  and  of 
course  will  not  be  likely  to  occur  at  the  same 
period  of  life  with  the  abscess.  A  sense  of 
fluctuation  is  generally  perceptible  in  psoas 
abscess ;  not  so  with  hernia.  The  abscess  is 
preceded  by  pain  and  weight  in  the  loins  and 
by  shivering.  It  is  a  scrofulous  complaint,  and 
there  will  probably  be  other  indications  of  the 
diathesis,  such  as  the  transparent  skin,  the 
thickened  upper  lip,  or  perhaps  ill-conditioned 
scars  about  the  neck.    Any  of  these  symptoms 


HERNIA. 


761 


taken  singly  may  prove  but  an  indifferent  dia- 
gnostic, but  in  the  aggregate  they  establish  such 
distinction  that  it  must  be  the  result  of  sad  in- 
attention or  of  actual  ignorance  if  any  serious 
mistake  is  committed. 

It  has  been  stated  that  a  varix  of  the  saphena 
vein  may  present  symptoms  and  appearances 
strongly  resembling  crural  hernia,  inasmuch 
as  the  tumour  disappears  under  pressure  or  in 
the  horizontal  posture,  and  returns  again  imme- 
diately on  these  influences  being  removed,  and 
also  as  it  receives  a  certain  degree  of  impulse 
from  coughing  or  sneezing.  From  anatomical 
considerations  it  would  almost  seem  impossible 
that  such  an  error  could  be  committed,  and  at 
first  sight  the  observation  seems  to  have  been 
made  for  the  purpose  of  creating  nice  distinc- 
tions and  rendering  the  subject  apparently  com- 
plete rather  than  for  any  practical  utility.  A 
case,  however,  is  related  by  Petit,  who  distin- 
guished the  real  nature  of  the  tumour  by  its 
dark-coloured  appearance  and  by  the  general 
varicose  state  of  the  remainder  of  the  vein.  If 
difficulty  is  experienced  in  any  particular  case, 
it  may  be  easily  resolved  by  making  pressure 
on  the  trunk  of  the  iliac  vein  above  Poupart's 
ligament,  when  the  tumour  will  re-appear,  even 
although  the  patient  maintains  the  horizontal 
posture. 

"  Fatty  tumours  are  not  unfrequently  found 
on  dissection  occupying  the  exact  situation  of 
crural  hernia.  I  have  not  had  an  opportunity 
of  seeing  any  case  of  this  kind  in  the  living 
body,  but  have  had  occasion  to  remark  at  least 
five  or  six  instances  of  it  every  season  in  the 
dissecting  room,  from  which  I  presume  such 
tumours  are  more  common  than  is  generally 
suspected.  In  all  those  instances  the  fatty  tu- 
mour was  connected  with  or  rather  seemed  to 
grow  from  the  outer  surface  of  the  peritoneum 
lining  the  crural  ring;  and  the  inner  surface  of 
this  membrane  when  viewed  from  the  abdomen 
had  a  contracted,  wrinkled,  and  thickened  ap- 
pearance, resembling  very  closely  the  appearance 
of  a  reduced  hernial  sac.  Whether  the  perito- 
neum had  been  protruded  in  these  instances 
I  cannot  pretend  to  say ;  nor  can  I  venture  to 
lay  down  the  symptoms  which  should  guide  us 
in  our  diagnosis  in  the  living  body.  This 
much  at  least  is  obvious,  that  these  steatoma- 
tous  tumours  will  not  be  accompanied  by 
symptoms  of  strangulation."* 

Umbilical  hernia. —  The  navel  is  the  remnant 
of  an  aperture  that  had  been  situated  nearly  in 
the  centre  of  the  front  of  the  belly,  but  nearer  to 
the  pubis  than  to  the  ensiform  cartilage:  it  is 
placed  in  the  lmea  alba, and  of  course  its  edges 
are  tendinous.  During  foetal  life  it  serves  for 
the  transmission  of  the  umbilical  vein  and  arte- 
ries, but  its  size  is  greater  than  would  merely 
suffice  for  the  passage  of  these  vessels,  in  order 
that  the  circulation  of  the  blood  through  them 
should  suffer  no  interruption  by  accidental  com- 
pression ;  and  in  a  foetus  of  seven  months  the 
edge  of  the  aponeurotic  opening  is  still  thin, 
weak,  and  unresisting.    After  birth,  when  the 

*  This  passage  is  copied  from  Colles's  Surg.  Ana- 
tomy, p.  84. 


navel  string  (as  it  is  called )  has  dropped  off, 
the  umbilical  aperture  begins  to  close,  until 
finally  that  puckered  cicatrix  is  formed,  the 
appearance  of  which  is  so  familiar;  but  the 
periods  at  which  this  process  commences  and  is 
completed,  and  the  circumstances  that  may 
occur  to  interfere  with  it,  are  of  some  importance 
with  reference  to  the  phenomena  of  hernia. 
Scarpa  says  that  it  begins  immediately,  and  that 
if  the  finger  is  passed  up  the  peritoneal  wall  of 
the  abdomen  in  a  child  two  months  after  birth, 
not  only  will  the  navel  be  found  firmly  formed 
and  completely  cicatrised,  but  there  will  be  a 
knot  or  elevation  felt  at  this  spot,  shewing  that 
it  is  then  really  stronger  than  most  other  parts 
of  the  abdominal  parietes  Lawrence  states 
that  the  contraction  commences  about  the  third 
or  fourth  month  after  birth,  and  thence  inculcates 
the  necessity  of  an  infant  being  tolerably  accu- 
rately bandaged  anterior  to  that  period  in  order 
to  prevent  the  occurrence  of  umbilical  rupture 
from  its  struggles  or  its  cries.  It  is  not  of 
much  consequence  which  of  these  opinions 
may  be  correct :  probably  both  are  so  to  a  cer- 
tain extent,  for  the  opening  is  larger  in  some 
infants  than  in  others,  and  will  require  a  longer 
time  to  close,  and  the  process  of  obliteration 
does  not  commence  in  all  exactly  at  the  same 
period  after  birth.  Whatever  variety  may 
exist  in  this  respect,  when  the  process  is  com- 
plete the  umbilicus  can  never  afterwards  be 
called  an  aperture;  it  never  again  re-opens;  and 
when  ruptures  are  observed  in  after-life  seem- 
ing to  occupy  this  situation,  it  will  be  found  on 
examination  that  some  neighbouring  parts  of 
the  linea  alba  have  given  way,  and  the  disease 
more  strictly  belongs  to  the  ventral  than  to 
umbilical  hernia. 

It  appears  then  that  by  the  salutary  provi- 
sions of  nature  the  front  of  the  abdominal  pa- 
rietes is  well  supported,  and  the  contained 
viscera  protected  from  protrusion  ;  and  even  if 
the  operations  by  which  the  umbilicus  is  closed 
should  be  accidentally  suspended  or  interfered 
with,  (as  by  the  presence  of  a  hernia  for  in- 
stance,) the  disposition  is  not  lost,  and  the  aper- 
ture preserves  its  tendency  to  close  and  become 
obliterated  for  the  first  five  or  six  years  of 
childhood.  Thus  at  any  time  within  that  period 
there  may  be  a  reasonable  probability  of  obtain- 
ing a  permanent  cure  of  umbilical  hernia; 
whereas  after  the  age  of  ten  or  twelve  years  this 
disposition  ceases  to  operate,  or  at  least  is 
greatly  impaired,  and  there  is  little  or  no  chance 
of  so  fortunate  an  occurrence. 

The  condition  in  which  the  umbilicus  exists 
at  and  after  birth  divides  the  hernia?  that  occur 
in  this  situation  into  different  orders  according 
as  they  may  appear  at  the  period  of  birth  or 
afterwards.  Scarpa  considers  the  disease  to 
consist  of  only  two  species,  the  congenital  and 
the  adventitious — the  congenital  being  that 
which  appears  in  the  infant  when  born,  and  the 
other  occurring  at  any  subsequent  period. 
Lawrence  speaks  of  three  kinds,  the  congenital, 
that  which  appears  at  birth,  and  in  which  the 
protruded  viscera  are  lodged  in  the  umbilical 
cord;  the  umbilical  hernia  of  children  occur- 
ring after  the  navel  has  been  formed,  but  pro- 


702 


HERNIA. 


trading  through  the  original  deficiency  in  the 
linea  alba  ;  and  the  hernia  of  adults,  which  has 
some  peculiarities  that  shall  be  noticed  here- 
after. 

The  congenital  umbilical  hernia  seems  to 
depend  rather  on  a  deficiency  of  the  anterior 
walls  of  the  abdomen  than  on  any  other  cause, 
and  in  the  cases  in  which  it  is  observed,  the 
aperture  at  the  navel  is  much  larger  than  it 
should  naturally  be,  and  its  tendinous  edges 
excessively  thin  and  weak.  The  deficiency  of 
the  abdominal  parietes  ranks  amongst  natural 
malformations,  and  it  is  astonishing  to  what  an 
extent  it  has  been  observed.  The  entire  of  the 
tendinous  front  of  the  belly  has  been  found 
imperfect,  and  nearly  the  whole  of  the  viscera 
displaced,  thus  forming  an  immense  rupture 
covered  at  its  base  and  for  some  extent  farther 
by  the  skin  and  superficial  investments  of  the 
body,  and  in  its  remaining  part  by  the  transpa- 
rent spongy  substance  of  the  umbilical  cord. 
The  contents  of  these  ruptures  are  greatly  varied : 
the  liver  or  a  portion  of  it,  the  spleen,  the 
stomach,  the  greater  and  the  lesser  intestines 
have  all  been  occasionally  found  thus  circum- 
stanced, but  more  particularly  the  omentum, 
which,  as  might  be  anticipated  from  its  situation, 
is  observed  to  constitute  a  part  of  almost  every 
umbilical  hernia  both  in  the  old  subject  and  in 
the  young.  Whenever  there  is  such  a  defi- 
ciency in  the  abdominal  parietes,  the  pressure 
an  infant  undergoes  in  coming  into  the  world 
materially  contributes  to  the  production  of 
hernia,  and  accordingly  it  is  observed  most  fre- 
quently after  a  protracted  and  difficult  labour ; 
and  if  it  is  large,  and  the  contents  of  the  ab- 
domen extensively  deranged  or  displaced,  it  is 
in  general  fatal,  the  infant  seldom  surviving 
beyond  two  or  three  days,  and  perhaps  not  so 
long.  In  this  affection  there  seems  to  be  a 
want  of  correspondence  between  the  size  of  the 
viscera  and  that  of  the  abdominal  cavity,  the 
former  appearing  enlarged  and  swollen  ;  and 
there  is  seldom  a  possibility  of  returning  the 
rupture,  or  of  maintaining  it  so  if  reduced. 
There  is  in  general  also  in  these  cases  some 
other  malformation  or  incomplete  development 
to  account  for  the  fatality  that  so  uniformly 
attends  them.  But  if,  on  the  other  hand,  the 
hernia  is  small,  the  case  is  by  no  means  neces- 
sarily attended  with  danger :  the  rupture  may 
be  reduced,  but  it  has  a  tendency  to  return  when- 
ever the  child  cries  or  makes  any  other  exertion, 
and  it  is  extremely  difficult  to  restrain  it  by  a 
bandage  ;  but  if  it  can  be  kept  up  for  a  few 
months,  the  umbilical  aperture  closes  as  it 
would  have  done  if  there  had  been  no  pro- 
trusion, and  the  cure  is  permanent  and  com- 
plete. 

If,  before  the  navel  has  become  cicatrized  and 
closed,  a  portion  of  any  vistus  should  happen 
to  be  protruded  through  it,  and  its  progress 
towards  obliteration  thus  interrupted  ;  or  if  the 
contraction  has  been  delayed  longer  than  usual, 
and  an  aperture  thus  left  ready  to  favour  the 
escape  of  a  part  of  intestine  from  its  natural 
situation,  the  rupture  will  be  of  the  second 
form  mentioned,  namely,  the  umbilical  hernia 
of  the  child.    This  differs  from  that  of  the 


infant  inasmuch  as  it  is  covered  by  the  skin  and 
the  cicatrized  knot  of  the  navel,  and  does  not 
lie  within  the  cord ;  and  from  that  of  the  adult, 
so  far  as,  if  replaced  and  prevented  from  again 
protruding,  the  aperture  will  gradually  contract, 
and  thus  a  permanent  cure  be  obtained,  which 
is  scarcely  to  be  expected  at  a  more  advanced 
period  of  life.  It  has  been  already  mentioned 
that  Scarpa  considered  the  perfect  contraction 
of  the  umbilicus  to  be  completed  in  about  two 
months,  and  at  the  end  of  that  time  that  it  is 
even  firmer  than  other  parts  :  he  moreover 
seemed  to  think  this  part  materially  strength- 
ened by  the  remains  of  those  vessels  which 
before  birth  made  up  a  part  of  the  cord.  The 
umbilical  vein  passing  from  the  navel  upwards 
towards  the  liver,  and  the  hypogastric  arteries 
passing  downwards, are  at  the  umbilicus  united 
by  a  cicatrix  to  the  skin  and  to  each  other,  and 
contnbute  to  prevent  the  yielding  of  the  part  as 
soon  as  they  become  ligamentous.  The  point 
of  union  of  these  vessels  must  be  pushed 
forwards  as  well  as  the  integuments  in  adven- 
titious hernia,  and  hence  it  happens  that  when 
the  umbilical  aperture  is  only  of  its  natural 
size,  the  rupture  that  takes  place  (if  any)  is 
small ;  and  in  cases  where  it  is  large  and  the 
abdominal  parietes  deficient  in  this  point,  the 
tumo  ur  is  flatter  and  more  compressed  than 
might  have  been  otherwise  expected,  and  some 
of  these  vessels  are  found  lying  on  it  and 
forming  a  part  of  its  covering. 

In  persons  more  advanced  in  life  in  whom 
the  opening  in  the  tendon  had  been  perfectly 
closed,  Scarpa  denies  that  it  ever  becomes 
relaxed  again,  and  therefore  states  that  the  rup- 
tures which  occur  from  over-distension,  from 
pregnancy,  or  as  the  sequels  of  dropsy,  are 
not  situated  in  the  original  umbilical  canal,  but 
in  some  part  of  the  linea  alba  that  has  more 
recently  given  way,  and  of  which  the  umbilicus 
happens  to  form  a  part.  He  states  further  that 
the  linea  alba  is  not  equally  strong  and  firm  in 
all  its  parts  ;  that  above  the  navel  it  becomes 
gradually  thinner,  and  in  women  who  have 
borne  many  children  it  is  uneven  in  consistence, 
and  in  some  parts  so  weak  as  to  be  liable  to 
yield  and  tear  on  a  very  slight  exertion.  Hence 
it  happens  that  these  ventro-umbilical  ruptures 
generally  occur  rather  above  the  navel;  and  the 
almost  obliterated  remains  of  this  cicatrix  (for 
by  the  distension  it  becomes  nearly  smooth)  is 
scarcely  ever  observed  to  occupy  the  centre  of 
the  tumour,  but  is  found  to  one  side  and  almost 
placed  inferiorly.  In  the  dissection  of  these 
tumours  a  laceration  or  fissure  is  constantly 
met  with  in  the  linea  alba,  sometimes  transverse, 
but  more  generally  longitudinal,  and  this  is  one 
reason  why  the  umbilical  ruptures  of  old  per- 
sons are  not  susceptible  of  a  radical  cure,  for 
there  is  a  great  difference  between  a  natural 
opening,  the  tendency  of  which  is  to  contract 
and  close,  and  one  made  by  the  yielding  and 
laceration  of  part  of  the  linea  alba  or  other 
tendinous  portion  of  the  abdominal  parietes, 
which  certainly  cannot  be  supposed  to  be  en- 
dowed with  strong  reparative  properties. 

There  was  a  question  formerly  raised  as  to 
whether  umbilical  hernia  possessed  a  peritoneal 


HERNIA. 


763 


sac,  and  it  was  generally  believed  that  no  such 
investment  had  any  existence  in  the  disease. 
Garengeot  in  his  paper  on  singular  species  of 
hernia?  expressly  states  that  ruptures  of  this 
kind  were  deficient  in  this  particular,  and  he 
was  followed  by  Petit  and  almost  all  the  elders 
of  our  profession,  who,  to  spare  themselves  the 
labour  of  investigation,  copied  from  each  other 
errors  as  well  as  truth.  It  is  really  curious  to 
observe  how  a  mistake  could  have  so  long 
maintained  its  ground  that  could  have  been  set 
at  rest  by  half-an-hour's  dissection;  and  indeed 
it  is  in  some  respects  surprising  how  such  an 
opinion  came  to  be  entertained  at  all.  In  every 
case  of  umbilical  hernia  there  must  of  neces- 
sity be  a  sac,  because  the  peritoneum  is  not 
deficient  at  the  navel,  and  the  vessels  that  pass 
within  the  cord  do  not  enter  the  cavity :  they 
lie  anterior  to  it,  and  are  partly  invested  by  the 
membrane,  which  is  entire  and  complete  behind 
the  navel,  and  neither  intestine  nor  omentum  can 
be  protruded  without  pushing  it  out  before  it, 
and  thus  constituting  a  proper  hernial  sac.  It 
may  be  that  in  large  umbilical  hernia?  the  peri- 
toneum shall  have  become  very  thin,  so  that  the 
peristaltic  motions  of  the  intestines  may  be 
easily  perceived  through  it  from  without;  or  it 
may  have  been  burst  accidentally,  and  in  either 
of  these  cases  there  will  be  an  appearance  as  if 
there  had  been  in  reality  no  sac.  And  more- 
over, the  peritoneum  immediately  behind  the 
navel  is  not  connected  to  it  by  the  same  loose 
and  distensible  cellular  tissue  that  unites  it  to 
other  parts  :  it  is  here  very  closely  joined,  and 
consequently  in  small  ruptures  only  occupying 
this  spot  there  will  be  no  appearance  of  a  sepa- 
rate and  distinct  sac,  although  the  peritoneal 
covering  is  really  there  notwithstanding.  It 
must  be  borne  in  mind,  however,  that  invest- 
ments of  umbilical  ruptures  are  always  very 
thin,  and  a  proportionate  degree  of  caution  is 
requisite  in  cutting  through  them  during  ope- 
ration. There  are  no  distinct  layers  of  fascia 
here  as  in  other  ruptures,  no  lamina;  to  sepa- 
rate one  by  one  and  one  after  another.  In  the 
congenital  species  the  contents  of  the  sac  are 
merely  covered  by  the  peritoneum  and  the 
sheath  of  the  cord.  In  the  infantile,  the 
coverings  are  the  skin  and  cicatrix  of  the  navel 
and  the  peritoneum  ;  and  in  the  adventitious 
kind  or  ventro-umbilical  we  meet  the  skin,  then 
the  superficial  fascia,  which  is  very  thin  and 
weak  on  this  part  of  the  abdomen;  next  the 
cellular  tissue  that  had  united  the  peritoneum 
to  the  adjacent  structures,  and  which  may  have 
become  condensed  so  as  to  form  a  kind  of 
fascia  propria;  and  lastly,  the  peritoneum  or 
hernial  sac  itself. 

In  almost  every  case  of  umbilical  hernia 
occurring  in  the  adult,  omentum  has  formed 
part  of  the  contents  of  the  sac,  at  least  the  ob- 
servation has  been  so  universally  made  that  the 
rule  may  be  considered  as  established.  In 
general  it  lies  before  the  intestine  in  such  a  po- 
sition as  to  conceal  it  altogether  and  make  it 
appear  as  if  no  other  viscus  was  engaged  ;  but 
sometimes  the  intestine  makes  a  passage  through 
it  and  presents  first  when  the  sac  is  opened ;  or 
both  these  structures  may  be  coiled  and  twisted 


together  in  such  wise  as  to  render  it  difficult  to 
unravel  and  separate  them  one  from  another, 
and  highly  perilous  to  return  them  in  that  con- 
dition into  the  cavity  lest  strangulation  should 
take  place  within.  From  the  circumstance 
also  of  containing  omentum,  umbilical  ruptures 
frequently  become  irreducible,  this  structure, 
when  protruded,  becoming  thickened  and  en- 
larged and  occasionally  loaded  with  fat,  so  as 
to  preclude  the  possibility  of  its  being  again 
returned  through  the  tendinous  opening.  Or 
adhesions  may  have  formed  between  the 
omentum  and  the  intestine,  or  between  either 
or  both  of  these  and  the  sac  :  in  short,  the 
rupture  may  become  irreducible  from  any  of 
the  causes  already  mentioned  as  capable  of 
producing  such  a  condition  of  parts,  but  the 
one  first  alluded  to,  namely,  the  thickening  and 
alteration  of  the  omentum,  is  the  one  most 
generally  observed. 

This  altered  condition  of  the  omentum  has 
also  a  paramount  influence  on  the  case  even  at 
a  more  remote  period.  Let  it  be  supposed  that 
symptoms  of  strangulation  have  supervened, 
and  an  operation  been  deemed  necessary  to 
preserve  existence,  the  presence  of  this  mass 
will  be  likely  to  prove  extremely  troublesome. 
Every  surgeon  is  conversant  with  the  different 
opinions  that  have  been  entertained  as  to  the 
manner  in  which  irreducible  omentum  should 
be  dealt  with.  Some*  speak  boldly  enough  of 
cutting  it  off  and  returning  any  part  that  might 
remain,  or  allowing  it  to  slip  back  into  the 
abdomen  without  feeling  any  apprehension 
from  the  possibility  of  haemorrhage.  Some 
have  tied  a  ligature  around  it  to  cause  it  to 
slough,  and  Mr.  Heyf  employed  a  ligature  in 
another  way  and  with  a  different  view,  namely, 
by  applying  it  so  tight  as  gradually  to  cut 
through  the  omentum  by  the  process  of  ab- 
sorption, but  without  entirely  destroying  the 
circulation  through  the  included  part.  Scarpa| 
left  the  omentum,  merely  covering  it  with  the 
sides  of  the  hernial  sac  and  dressing  it  lightly 
until  suppuration  appeared,  when,  he  said,  the 
pedicle  by  which  it  hung  might  be  safely  tied 
and  the  mass  cut  away.  I  notice  this  diver- 
sity of  opinion  not  for  the  purpose  of  incul- 
cating any  one  line  of  practice,  but  to  shew 
that  the  omentum  cannot  be  left  there  with 
safety.  It  is  at  all  times  and  under  every  cir* 
cumstance  not  very  highly  organized  or  able  to 
sustain  disease;  still  less  so  is  it  when  altered 
from  its  natural  arrangement,  converted  into  an 
unwieldy  mass  of  fat,  and  exposed  to  the  in- 
fluence of  the  atmosphere  in  an  open  wound. 
Sometimes  it  runs  into  tedious  and  unhealthy 
suppurations  with  profuse  and  wasting  dis- 
charges ;  more  generally,  if  the  patient  is  old 
and  debilitated,  into  mortification,  which  may 
(if  the  subject  lives  sufficiently  long)  pass  on 
to  the  unaltered  omentum  within  the  abdomen, 
nor  cease  until  it  has  reached  the  stomach. 

*  Pott,  op.  ciut.  p.  !  6.  Petit  and  Ponteau, 
Mem.  de  l'Acad.  Royale  de  Chir.  torn.  vii.  p.  338. 
Colles's  Surgical  Anatomy,  p.  100. 

t  In  this  he  was  anticipated  by  Morcau,  M£m. 
de  l'Acad.  Roy.  de  Ohir.  t.  vii.  p.  344. 

i  Op.  ckat.  p.  420. 


?64 


HIBERNATION. 


The  symptoms  of  umbilical  hernia  are 
easily  understood  by  referring  to  those  points 
in  which  it  differs  from  ruptures  situated  else- 
where. In  the  infant  the  tumour  appears  long 
and  thin,  according  to  the  quantity  of  viscera 
protruded  through  the  aperture  of  the  navel,  and 
projects  downwards  on  the  belly  :  its  coverings 
are  almost  transparent.  In  the  more  adult 
subject,  if  the  patient  is  thin  the  tumour  is  of 
a  pyriform  figure,  and  when  permitted  to  in- 
crease without  restraint  becomes  very  large 
and  hangs  pendulous  towards  the  pubes.  If 
he  is  fat  it  may  form  a  less  circumscribed 
swelling,  broad  and  flat,  apparently  extending 
in  every  direction  round  the  umbilical  aperture. 
The  sensation  imparted  to  the  finger  is  of  a 
soft  and  doughy  tumour  slightly  moveable 
under  the  skin,  but  sometimes  in  consequence 
of  the  presence  of  intestine  in  the  rupture  it 
may  possess  some  elasticity.  Occasionally, 
after  an  omental  hernia  has  remained  for  years 
without  producing  much  inconvenience,  it  sud- 
denly enlarges  towards  the  centre  and  assumes 
a  conical  chape,  the  apex  being  soft  and  elastic, 
the  base  hard  and  more  solid  :  in  this  case 
there  has  probably  been  a  fresh  protrusion  of 
intestine  which  has  burst  through  the  omentum 
and  requires  instant  attention,  as  so  circum- 
stanced it  is  extremely  liable  to  fall  into  a  state 
of  strangulation.  The  collateral  symptoms, 
such  as  nausea,  flatulence,  colicky  pains,  &c, 
are  more  severe  and  more  frequent  in  umbilical 
than  in  any  other  form  of  hernia,  a  circum- 
stance that  has  often  given  rise  to  the  idea  that 
the  stomach  formed  some  part  of  the  protrusion, 
but  perhaps  it  is  unnecessary  to  resort  to  such 
a  supposition,  for  probably  the  hernia?  of  the 
linea  alba  that  have  been  described  as  con- 
taining part  of  the  displaced  stomach  were  in 
no  wise  different  from  ordinary  umbilical 
ruptures  as  to  their  contents,  for  the  omentum 
being  protruded  will  be  sufficient  to  account 
for  every  aggravation  of  symptom. 

When  the  hernia  is  strangulated,  it  is  said 
that  the  symptoms  are  less  severe  and  less 
urgent  than  in  other  species  of  ruptures,  a  cir- 
cumstance that  has  also  been  accounted  for 
from  its  so  often  containing  omentum  alone. 
Sir  A.  Cooper  states  that  more  cases  of  stran- 
gulation occur  in  the  seasons  when  green  vege- 
tables are  plenty  than  in  others,  which  would 
seem  to  favour  the  idea  of  its  being  often  caused 
by  the  use  of  flatulent  or  indigestible  sub- 
stances. But  (except  with  reference  to  pre- 
vention) it  is  of  little  consequence  how  it  may 
be  caused,  or  whether  its  progress  is  rapid  or 
not.  When  once  formed,  it  must  be  reduced  ; 
and  it  runs  its  course  with  sufficient  rapidity  to 
render  it  extremely  alarming.  It  has  destroyed 
a  patient  in  less  than  eighteen  hours,  and 
although  such  severity  is  not  generally  to  be 
expected,  yet  in  this  or  in  any  other  kind  of 
hernia  the  smallest  unnecessary  delay  can 
never  be  justified. 

"  Sometimes  a  small  mass  of  indurated  fat, 
situated  between  the  peritoneum  and  its  union 
with  the  aponeurosis  of  the  abdominal  muscles, 
makes  its  way  insensibly  through  the  separated 
fibres  of  the  linea  alba,  and  is  at  last  elevated 


externally  in  form  of  a  tumour  which  seems  to 
have  all  the  characters  of  an  omental  hernia. 
The  existence  of  this  species  of  tumour  through 
the  linea  alba  is  not  only  a  certain  fact  and  de- 
monstrated by  several  observations  made  on  the 
dead  body  by  Morgagni,  by  Klinkosch  and 
several  others,  but  it  is  also  proved  that  it 
makes  its  appearance  in  other  parts  of  the 
linea  alba  besides  that  to  which  the  umbilical 
vein  corresponds  internally.  It  may  occur  that 
a  person  in  whom  a  similar  small  tumour  has 
existed  for  a  long  time  in  the  course  of  the 
linea  alba  may  be  attacked  from  a  quite  diffe- 
rent cause  by  violent  colic,  with  nausea,  incli- 
nation to  vomit,  and  interruption  to  the  alvine 
excretions.  The  surgeon,  in  similar  circum- 
stances, is  easily  led  into  error,"  (and  Scarpa 
committed  the  mistake  himself,)  "  presuming 
that  the  tumour  is  a  true  incarcerated  hernia  of 
the  linea  alba,  subjecting  the  patient  to  an  ope- 
ration which  has  no  connexion  with  the  cause 
of  the  disease."  Never  having  seen  any  similar 
tumour,  I  have  copied  the  above  passage  from 
Scarpa :  they  are  probably  of  the  same  nature 
with  those  described  by  Mr.  Colles  as  occa- 
sionally presenting  at  the  crural  ring.  The 
resemblance  must  be  strikingly  obvious  to 
every  reader. 

(  William  Henri/  Porter.) 

HIBERNATION  ;  etym.  hiberno,  to  win- 
ter, to  pass  the  winter;  syn.  lethargy  ;  errone- 
ously, torpor;  Fr.  sommeil  hivernal ;  Germ. 
Winterschlaf  and  Sommerschlqf ;  a  term  chiefly 
applied  to  express  that  condition  in  which  cer- 
tain animals  pass  the  winter  season. 

How  often  have  I  been  struck  with  admira- 
tion in  observing  how  variously  the  Creator  has 
provided  for  certain  of  the  insectivorous  tribes, 
the  swallow  and  the  bat,  for  example,  against 
the  period  when  the  sources  of  their  daily  food 
are  cut  off,  when  spring  and  summer  yield  to 
autumn  and  winter,  and  insects  disappear  !  The 
first  emigrates  to  a  more  genial  climate  where 
its  nutriment  still  abounds  ;  the  second  sinks 
into  a  deep  sleep,  in  which  food  is  unnecessary, 
and  which  continues  through  the  dreary  season 
of  cold  and  famine. 

It  has  not  hitherto  been  distinctly  ascertained 
to  what  extent  the  state  of  hibernation  prevails 
in  the  animal  kingdom;  the  bat,  the  hedgehog, 
and  the  dormouse,  are  the  genera  which  present 
us  with  the  most  marked  examples  of  this  sin- 
gular physiological  condition  in  this  country  ; 
to  these  the  elegant  authoress  of  "  Sketches  of 
Natural  History "  has  added  the  water-rat  and 
the  wood-mouse,  observing  of  the  former — 

"  And  when  cold  winter  comes  and  the  water- 
plants  die, 

And  his  little  brooks  yield  him  no  longer  supply, 

Down  into  his  burrow  he  cozily  creeps, 

And  quietly  through  the  long  winter-time  sleeps." 

But  before  we  proceed  to  discuss  this  ques- 
tion of  natural  history,  we  must  consider  that 
of  the  physiology  of  hibernation. 

There  is,  in  my  opinion,  an  ultimate  law  of 
animal  existence,  which  seems  to  regulate  the 
different  forms  in  which  the  different  classes  of 
animals  present  themselves.   The  quantity  of 


HIBERNATION. 


765 


respiration  is  inversely  as  the  degree  of  irritabi- 
lity of  the  muscular  fibre,  the  former  being 
marked  by  the  quantity  of  oxygen  consumed  in 
a  given  time,  ascertained  by  the  pneumatome- 
ter,*  the  latter  by  the  force  of  galvanism  neces- 
sary to  demonstrate  its  existence.  The  bird 
tribes  have  a  high  respiration  and  a  low  irrita- 
bility ;  the  reptiles  have  a  high  degree  of  irrita- 
bility and  little  respiration.  This  law  obtains 
not  only  in  the  different  tribes  of  animals,  but 
also  in  the  different  stages  or  states  of  the  same 
individual,  the  structural  changes  from  one 
stage  to  another  being  always  a  change  from  a 
lower  to  a  higher  respiration,  and  from  a  higher 
to  a  lower  degree  of  irritability,  and  the  change 
of  state,  a  change  in  the  opposite  direction  : 
thus  the  changes  from  the  egg  to  the  bird,  from 
the  tadpole  to  the  batrachian  form,  from  the 
larva  to  the  chrysalis  and  the  insect  condition, 
are  changes  in  which,  whilst  a  due  ratio  is  con- 
stantly maintained,  the  quantity  of  respiration 
is  augmented  and  the  degree  of  irritability 
diminished;  on  the  other  hand,  the  physiolo- 
gical changes  in  the  degree  of  activity  in  ani- 
mals, during  sleep,  for  example,  but  especially 
in  that  remarkable  change  which  is  the  subject 
of  this  article,  the  respiration  is  diminished 
whilst  the  degree  of  irritability  is,  pari  passu, 
augmented. 

On  what  this  susceptibility  of  change  de- 
pends, and  especially  on  what  the  power  of 
taking  on  an  augmented  irritability  depends,  is 
at  present  unknown.  But  1  think  I  may  affirm 
that  it  is  upon  this  power  that  the  capability  of 
passing  into  the  state  of  hibernation  reposes.  I 
suppose  that  all  animals  have  the  faculty  of 
sleeping;  during  sleep  the  respiration  is  slightly 
diminished,  the  irritability  probably  proportio- 
nately augmented — probably  one  ultimate  ob- 
ject of  this  state  of  repose ;  but  the  phenomenon 
has  its  appointed  limit  which  it  cannot  pass. 
In  certain  animals,  that  limit  is  not  so  con- 
fined,— the  quantity  of  respiration  is  still  further 
diminished,  the  decree  of  irritability  still  further 
augmented,  and  the  deeper  sleep,  or  lethargy, 
of  hibernation  takes  place. 

During  this  lethargy,  the  law  of  the  inverse 
ratio  of  the  respiration  and  of  the  irritability 
still  prevails,  and  the  animal  merely  puts  on  a 
reptile  state  in  these  respects.  Were  the  respi- 
ration to  be  diminished  without  the  appointed 
augmentation  of  the  irritability,  the  heart  would 
cease  to  be  stimulated,  and  the  animal  would 
die,  as  in  the  cases  of  torpor  and  slow  asphyxia; 
were  the  respiration  augmented  without  the 
proportionate  diminution  of  the  irritability,  the 
heart  would  be  over-stimulated,  and  death 
would  alike  ensue,  as  in  the  case  of  a  hiberna- 
ting animal  too  suddenly  roused  from  its  lethar- 
gy, and  as  (probably)  in  the  case  of  an  animal 
placed  in  pure  oxygen  gas. 

The  difference  between  the  hibernating  and 
all  other  animals  then  is,  an  ultimate  faculty  of 
assuming  an  augmented  degree  of  irritability  of 
the  muscular  fibre- — a  power  possessed  by  all 
animals  within  certain  limits,  but  by  the  hiber- 
nating animal  beyond  the  usual  limit. 

*  See  Phil.  Trans,  for  1832,  p.  323. 


Sleep,  however  inscrutable  in  itself,  is  the 
connecting  link  between  the  two  physiological 
states;  a  disquisition  on  hibernation  is,  there- 
fore, a  disquisition  on  sleep — on  profound  sleep. 
It  will  shortly  appear  that  one  eminent  philoso- 
pher has  fallen  into  the  error  of  assimilating 
different  physiological  phenomena  by  neglect- 
ing to  take  this  fact  into  his  consideration. 
Sleep  and  hibernation  are  similar  periodical 
phenomena,  induced  by  similar  causes,  leading 
to  similar  effects,  and  differing  only  in  degree. 
Hibernation  appears  more  extraordinary  only 
because  less  familiar  than  sleep.  Most  animals 
are,  in  fact,  naturally  awake  and  asleep  every 
revolving  day,  some  being  diurnal,  others  noc- 
turnal. But  in  summer  the  bat  actually  hiber- 
nates, loses  its  respiration,  and  with  its  respira- 
tion its  temperature,  acquires  vastly  augmented 
irritability,  and  presents  the  other  phenomena 
of  complete  hibernation,  regularly  and  periodi- 
cally every  twenty-four  hours  ;  and  the  hedge- 
hog and  the  dormouse  present  simiiar  pheno- 
mena, only  after  other  intervals. 

Sleep  then  is  the  first  stage  of  hibernation. 
The  faculty  of  passing  into  the  second  is  iden- 
tical with  that  of  assuming  a  greatly  augmented 
irritability  of  the  muscular  fibre.  Such  are  the 
results  of  my  long  attention  to  this  interesting 
physiological  question.  Much  error  has  arisen 
from  viewing  hibernation  as  a  simple  effect  of 
cold.  The  influence  of  cold  in  inducing  hiber- 
nation is  merely  its  well-known  influence  in 
inducing  sleep,  concurring  with  the  other  causes 
of  this  condition.  The  direct  effect  of  cold  on 
the  animal  frame  is,  as  I  shall  shortly  have 
occasion  to  state  particularly,  totally  different 
from  hibernation.  Hibernation  is  a  physiolo- 
gical condition;  the  direct  effect  of  cold,  or 
torpor,  is,  on  the  contrary,  a  pathological  and 
generally  a  fatal  one. 

The  term  hibernation  has  usually  been  ap- 
plied to  designate  what  its  etymology  implies, 
the  condition  in  which  certain  animals  pass  the 
winter  season.  An  error  is,  as  I  have  already 
stated,  involved  in  this  view  of  the  subject ;  for 
the  condition  termed  hibernation  is  not  con- 
fined to  the  winter  season.  Cuvier  observes, 
in  speaking  of  the  Tenrecs,  "  ce  sont  des  ani- 
maux  nocturnes  qui  passent  trois  mois  de 
l'annee  en  lethargie,  quoique  habitants  de  la 
zone  torride.  Burguifere  assure  meme  que  c'est 
pendant  les  grandes  chaleurs  qu'ils  dorment."* 
Hence  the  term  Sommerschhif  employed  in  Ger- 
many. It  is  plain  too,  from  this  circumstance, 
that  the  state  of  hibernation  is  not  necessarily 
connected  with  a  low  degree  of  external  tempe- 
rature, and  we  are  surprised  to  find  this  cele- 
brated naturalist,  whom  I  have  just  quoted, 
observing,  "  la  seule  condition  de  la  lethargie 
est  le  froid  et  l'absence  des  causes  irritantes."  f 

I  must  repeat  that  hibernation  is,  in  every 
respect,  but  the  parallel  of  ordinary  sleep,  vary- 
ing only  in  force  and  duration.  It  is  equally 
marked  by  an  inexplicable  periodicity ;  it  is 
equally  modified  by  cooperating  or  opposing 

*  Regne  Animal,  ed.  1829,  t.  i.  p.  125. 
t  Histoire  des  Sciences  Natuielles,  1829,  t.  i. 
p.  280. 


766 


HIBERNATION. 


causes ;  and  it  is  equally  manifested  in  its  pe- 
culiar effects,  only  varying  in  degree  and  inten- 
sity. 

In  giving  a  distinct  idea  of  hibernation  we 
must  extend  our  views  to  the  altered  condition 
of  each  function  in  the  animal  economy,  for 
this  peculiar  state  is  not  limited  to  any  special 
function  or  organ.  It  is,  in  fact,  a  treatise  on 
physiology  which  should  be  written,  compa- 
ring the  state  of  each  function  and  of  each 
organ,  in  the  hibernant  or  lethargic  and  in  the 
active  condition,  a  disquisition  on  sleep,  indeed, 
in  its  various  degrees,  and  in  its  effects  in  mo- 
difying the  various  functions. 

The  first  question  then  is, — what  is  sleep  ?  a 
question  difficult,  perhaps  impossible,  to  an- 
swer, if  we  mean  by  it  what  is  its  nature  or 
essence,  but  highly  interesting  to  prosecute,  if 
we  mean  what  are  its  special  phenomena  and 
their  mutual  relations. 

In  order  to  treat  of  sleep  properly,  I  must 
first  observe  that,  of  the  nervous  system,  of 
which  it  is  primarily  a  modification,  formerly 
divided  into  the  cerebrospinal  and  the  ganglio- 
nic, the  first  division  must  now  be  subdivided 
into  the  cerebral  and  the  true  spinal,  the  former 
being  the  exclusive  seat  of  sensation,  volition, 
&c. ;  the  latter,  the  special  source  of  certain 
actions  now  designated  excito-motory,  and  ob- 
served in  the  orifices,  the  ingestors,  the  expul- 
sors,  the  sphincters,  &c.  Now  it  is  the  cere- 
bral system  which  sleeps,  the  true  spinal  re- 
taining all  its  energies. 

From  this  enunciation  of  the  primary  fact  in 
sleep,  we  may  trace  the  whole  of  the  pheno- 
mena of  this  singular  condition.  In  the  state 
of  activity,  the  cerebral  system  exerts  a  peculiar 
and  continual  influence  over  the  true  spinal, 
which  ceases  during  sleep.  In  this  manner  the 
functions  of  the  latter  appear  impaired  ;  the  re- 
spiration especially,  and  with  the  respiration 
the  circulation,  with  which  it  always  maintains 
a  certain  relation,  becomes  slower,  irregular, 
and  suspended  at  intervals.  These  phenomena 
observable  in  ordinary  sleep  are  still  more  re- 
markable in  the  deep  sleep  or  lethargy  of 
hibernation  or  diumation. 

In  order  that  the  effects  of  hibernation  may 
be  traced  in  relation  to  all  the  functions  of  the 
animal  economy,  I  must  enter  into  a  few  brief 
details  relative  to  the  arrangement  of  these 
functions  and  the  order  in  which  I  propose  to 
notice  them.  The  most  simple  and  natural 
arrangement  of  the  functions  appears  to  me  to 
be  the  following  : — 

I.  Sanguification. 

1.  The  ingestion  and  >   cc  , 
rpi    j '     * ■  t  of  food. 

2.  The  digestion  . . . .  J 

„  r™    r  ( a.  of  chyme. 

3.  The  formation....  ^  6fchJle. 

. ,  (  a.  by  the  Iacteals. 

4.  Absorption  |  6.  bJ  imbibition. 

5.  The  organization  of  the  blood. 

II.  Respiration. 

-   rrx,      i       .•  S  «•  of  oxygen.  • 

1.  The  absorption  . .  \  ,     f  -;  b  B 

r  (b.  of  nitrogen,  &c. 

••,  a.  of  carbonic  acid. 


3.  The  results 


s 


a.  augmented  temperature. 

b.  a  direct  ratio  between  the 
pulsations  and  respirations. 

c.  an  inverse  ratio  between 
the  respiration  and  irrita- 
bility. 


2.  The  exhalation 


' "  I  b.  of  nitrogen,  See. 


III.  The  Circulation. 

1.  The  pulmonic. 

2.  The  systemic. 

3.  The  cardiac  or  coronary. 

4.  The  hepatic. 

5.  The  splenic. 

6.  The  circulation  as  the  (  a.  of  nutrition. 

carrier  lb.  of  temperature. 

IV.  Defcecation. 

1.  Re-absorption  by  the  lymphatics. 

f  a.  by  the  lungs. 
«  b.  by  the  skin. 

2.  Excretion  <*  c.  by  the  liver. 

J  d.  by  the  kidneys, 
v  e.  by  the  intestines. 

V.  The  Nervous  System. 

1.  The  cerebral,  or  the  system  of 

a.  The  sensations,  the  senses. 

b.  Volition,  spontaneous  motion. 

2.  The  true  spinal  or  excito-motory,  or  the 

system  of 

a.  The  orifices. 

b.  Ingestion. 

c.  Expulsion. 

d.  The  sphincters. 

3.  The  ganglionic. 

VI.  The  Muscular  System. 

1.  The  irritability. 

2.  The  motility. 

I  proceed  to  trace  the  influence  of  sleep,  and 
of  the  deeper  sleep  of  hibernation  upon  these 
various  functions,  beginning  with  the  former. 

I.  Of  sleep. — It  was  first  ascertained  experi- 
mentally by  Messrs.  Allen  and  Pepys,  that  the 
quantity  of  respiration  is  diminished  in  ordinary 
sleep.*  The  acts  of  respiration  are  obviously 
less  frequent  and  less  regular,  being  frequently 
suspended  for  a  moment  and  renewed  by  a  deep 
inspiration.  The  animal  frame  becomes  more 
susceptible  of  the  influence  of  cold.  It  is  most 
probable  that,  during  this  condition,  the  irrita- 
bility of  the  muscular  system  is  augmented, 
and  that  this  is  one  of  the  final  objects  of  sleep; 
experiments,  however,  are  still  wanting  to 
establish  a  fact  in  reference  to  ordinary  sleep, 
which  is  clearly  proved  in  regard  to  the  sleep 
of  hibernating  animals,  and  the  deeper  sleep  or 
lethargy  of  hibernation.  I  shall  now  proceed 
to  treat  of  the  sleep  of  hibernating  animals. 

II.  Of  the  sleep  of  hibernating  animals. — In 
the  sleep  of  the  hibernating  animal,  the  respira- 
tion is  more  or  less  impaired  :  if  the  animal  be 
placed  in  circumstances  which  best  admit  of 
observation,  the  acts  of  respiration  will  be 
found  to  have  greatly  diminished ;  if  it  be 
placed  in  the  pneumatometer,  little  alteration  is 

*  Phil.  Trans,  for  1809. 


HIBERNATION. 


767 


induced  in  the  bulk  of  the  air;  if  its  tempera- 
ture be  taken  by  the  thermometer,  it  will  be 
found  to  be  many  degrees  lower  than  that  of 
the  animal  in  its  active  state ;  if  it  be  deprived 
of  atmospheric  air,  it  is  not  immediately  in- 
commoded or  injured. 

These  facts  I  have  observed  in  the  hedge- 
hog,* the  dormouse,f  and  the  bat.J  If  other 
authors  have  not  made  the  same  observations, 
it  is  because  they  have  not  been  aware  how 
easily  this  sleep  is  disturbed.  To  walk  over 
the  floor,  to  touch  the  table,  is  sufficient,  in 
many  instances,  to  rouse  the  animal,  to  re-pro- 
duce respiration,  and  to  frustrate  the  experi- 
ment. 

The  bat,  which  is  a  crepuscular  or  nocturnal 
feeder,  regularly  passes  from  its  state  of  activity 
to  one  which  may  be  designated  diwnation. 
The  respiration  and  the  temperature  fail;  the 
necessity  for  respiration  is  greatly  lessened. 

During  the  summer  of  1831,  I  carefully  ob- 
served a  bat  in  this  condition.  If  it  were  quite 
quiet,  its  respiration  became  very  imperfect; 
its  temperature  was  but  a  few  degrees  above 
that  of  the  atmosphere ;  being  placed  under 
water,  it  remained  during  eleven  minutes  unin- 
jured, and  on  being  removed  became  lively 
and  continued  well. 

I  have  more  recently  watched  the  habits  of 
two  hedgehogs,  in  a  temperature  varying  from 
45°  to  50°.  These  animals  alternately  awake, 
take  food,  and  fall  asleep.  One  of  them  is 
frequently  awake,  whilst  the  other  is  dormant, 
and  goes  to  sleep  at  a  time  that  the  other 
awakes,  but  without  regularity.  When  awake, 
the  temperature  of  each,  taken  by  pressing  the 
bulb  of  a  thermometer  upon  the  stomach,  is 
about  95° ;  when  dormant,  it  is  4.5° ;  that  of 
the  atmosphere  being  42°  or  43°.  The  duration 
of  this  sleep  is  from  two  to  three  days,  accord- 
ing to  the  temperature  of  the  atmosphere.  On 
the  4th  of  February,  1832,  the  temperature  of 
the  atmosphere  being  50°,  both  the  hedgehogs 
were  dormant, — the  temperature  of  one  was 
51°,  and  that  of  the  other  52°;  on  the  succeed- 
ing day,  the  temperature  of  the  atmosphere  had 
fallen  one  degree,  the  temperature  of  one  of  the 
hedgehogs  was  49°,  whilst  that  of  the  other, 
which  had  become  lively,  had  risen  to  87°;  on 
the  succeeding  day,  the  first  had  become  some- 
what lively,  and  its  temperature  had  risen  to 
60°,  that  of  the  other  being  85°,  and  that  of  the 
atmosphere  47°. 

I  have  observed  precisely  the  same  alterna- 
tions in  the  dormouse  ;  except  that  this  animal 
awakes  daily  in  moderate  temperatures,  takes 
its  food,  and  re-passes  into  a  state  of  sleep,  in 
which  the  respiration  is  greatly  impeded,  and 
the  temperature  little  higher  than  that  of  the 
atmosphere. 

On  the  day  on  which  the  observations  were 
made  on  the  hedgehogs,  the  atmosphere  being 
49°,  that  of  two  dormice  was  52° ;  on  the  suc- 
ceeding day,  the  external  temperature  being 
47°,  that  is,  lower  by  two  degrees,  the  tempera- 

*  Erinacetis  Europrrns. 
+  Myoxua  avpllanariiis. 
%  Vespertilio  noclula. 


ture  of  one  of  these  dormice  was  92°,  and  that 
of  the  other  94°;  and  only  three  hours  after- 
wards, the  temperatures  were  60°  and  70°  re- 
spectively, with  a  slight  appearance  of  lethargy. 

The  hedgehog  and  the  dormouse  appear,  in 
fact,  to  awake  from  the  call  of  hunger,  then  to 
eat,  and  then  again  to  become  dormant,  in 
temperatures  which  may  be  termed  moderate. 
The  bat,  which  could  not  find  food  if  it  did 
awake,  does  not  undergo  these  periodical 
changes,  except  in  the  summer  season.  It  ap- 
pears to  me,  from  the  most  careful  observation, 
that  there  is  every  degree  between  the  ordinary 
sleep  of  these  animals  and  the  most  profound 
hibernation. 

It  is  quite  obvious,  from  these  observations, 
that  the  ordinary  sleep  of  hibernating  animals 
differs  from  that  of  others,  by  inducing  a  more 
impaired  state  of  the  respiration  and  of  the 
evolution  of  heat,  with  an  augmented  power  of 
bearing  the  abstraction  of  the  atmospheric  air. 
This  sleep  probably  passes  into  true  hiberna- 
tion, as  the  blood  which  circulates  through  the 
brain  becomes  more  and  more  venous,  from 
the  diminution  of  the  respiration,  and  as  the 
muscular  fibre  of  the  heart  acquires  increased 
irritability. 

It  is  absolutely  necessary,  in  comparing  the 
powers  of  hibernating  and  other  animals,  of 
evolving  heat,  accurately  to  observe  whether 
there  be  any  tendency  to  sleep.  Mr.  Hunter's 
and  M.  Edwards's  experiments  are  deficient 
for  want  of  this  attention.  Mr.  Hunter,  com- 
paring the  common  mouse  and  the  dormouse, 
exposed  to  a  very  low  temperature,  observes, 
that  the  temperature  of  the  former  was  "  dimi- 
nished 16°  at  the  diaphragm,  and  18°  in  the 
pelvis  ;  while  in  the  dormouse  it  gained  five 
degrees,  but  lost  on  a  repetition."  *  The  ex- 
planation of  these  facts  is  afforded  by  the  obser- 
vation, that  when  the  dormouse  increased  in 
temperature  it  was  "  very  lively,"  but  that  on 
the  "  repetition"  it  had  become  "  less  lively  ;" 
the  mouse  was  probably  in  a  state  of  languor 
from  apprehension  or  for  want  of  food. 

M.  Edwards  omits  to  mention  whether  the 
hibernating  animals,  in  his  experiments,  were 
disposed  to  be  lively  or  dormant,  or  whether 
they  had  recently  recovered  from  the  dormant 
state.  He  does  not  even  mention  whether  the 
experiments  on  the  bat  were  performed  in  the 
evening,  its  period  of  activity,  or  in  the  morn- 
ing or  day,  its  period  of  lethargy  or  diurnation. 
Without  a  particular  attention  to  these  points, 
no  correct  result  could  be  obtained.  The  hiber- 
nating animal,  in  a  state  of  vigour  and  activity, 
is  a  totally  different  being  from  the  same  animal 
disposed  to  become  dormant. 

In  order  to  perform  this  experiment  in  a 
satisfactory  manner,  the  bat,  for  example, 
should  be  employed  in  the  evening,  when  it 
has  naturally  awoke  from  its  deep  day-slumber, 
the  hedgehog  when  it  has  awoke  spontaneously 
to  take  food  ;  otherwise  the  disposition  to  sleep 
may  explain  the  loss  of  temperature.  We  must 
hesitate,  therefore,  in  subscribing  to  the  follow- 
ing conclusion  of  M.  Edwards:  "  No"«  voyons 

*  Animal  (Economy,  p.  114. 


768 


HIBERNATION. 


que  les  chauves-souris  produisent  habituelle- 
ment  moins  de  chaleur  que  les  animaux  a  sang 
chaud,  et  que  c'est  principalement  a  cette  cause 
qu'il  faut  attribuer  l'abaissement  de  leur  tempe- 
rature pendant  la  saison  froide.  En  comparant 
cette  experience  sur  la  chauve-souris  adulte 
avec  celles  que  nous  avons  faites  sur  les  jeunes 
animaux  a  sang  chaud,  on  y  apercoit  un  rap- 
port remarquable ;  ils  ne  produisent  pas  assez 
de  chaleur  pour  soutenir  une  temperature  elevee, 
lorsque  l'air  est  a  un  degre  voisin  de  zero. 
Mais  il  y  a  cette  difference,  que  c'est  un 
£tat  passager  chez  les  jeunes  animaux  a  sang 
chaud,  et  qu'il  est  permanent  chez  les  chauves- 
souris. 

"  II  est  evident  que  les  autres  mammiferes 
hibernans  doivent  participer  plus  ou  moins  de 
cette  maniere  d'etre.  Les  faits  que  j'ai  exposes 
suffisent  pour  nous  faire  considerer  ce  groupe 
d'animaux  sous  le  point  de  vue  suivant;  qu'au 
printemps  et  en  ete,  dans  leur  ttat  d'activite  et 
de  veille,  lorsque  leur  temperature  est  assez 
elevee  pour  ne  pas  diflerer  essentiellement  de 
celle  qui  caracterise  les  animaux  a  sang  chaud, 
ils  n'ont  pas  la  faculte  de  produire  autant  de 
chaleur;  et  tout  en  admettant  que  d'autres 
causes  peuvent  influer  sur  leur  refroidissement 
pendant  leur  hibernation,  il  faut  cependant 
l'attribuer  en  grande  partie  a  cette  particularite 
de  leur  constitution."  * 

There  are,  in  fact,  these  differences  between 
the  young  and  the  hibernating  animal:  1.  the 
former  cannot,  when  exposed  alone  to  severe 
cold,  maintain  its  own  temperature  ;  if  the  lat- 
ter appears  to  be  in  the  same  case,  it  is  only 
because  it  has  become  affected  with  its  peculiar 
lethargy;  in  its  state  of  wakefulness  and  activity 
it  maintains  its  usual  elevated  temperature  in 
the  same  manner  as  other  adult  animals  ;  2.  the 
young  animal,  in  losing  its  temperature,  be- 
comes affected,  not,  like  the  hibernating  animal, 
with  lethargy,  but  with  torpor,  a  totally  diffe- 
rent and  a  pathological  condition  which  gene- 
rally proves  fatal.  I  must  conclude  these  re- 
marks by  observing  that  I  think  the  eminent 
physiologist  whom  I  have  quoted  has  assimi- 
lated the  condition  of  the  very  young  animal 
and  the  adult  hibernating  animal  erroneously. 
The  mere  phenomenon  of  loss  of  temperature 
is  the  same ;  but  the  rationale  of  this  pheno- 
menon, its  causes  and  its  effects,  are  totally 
different. 

III.  Of  perfect  hibernation. — I  now  proceed 
to  treat  of  perfect  hibernation,  of  its  causes,  and 
of  its  effects  on  the  various  functions  which  I 
have  enumerated.  My  observations  will  con- 
sist principally  of  a  detail  of  a  series  of  obser- 
vations and  experiments  made  in  the  course  of 
the  year  1831-1832,  compared  with  the  results 
obtained  by  other  inquirers. 

I  consider  that  there  is  one  special  cause  of 
hibernation, — that  law  imposed  by  the  Creator, 
according  to  which  all  animals  become  affected 
with  sleep  at  some  period  of  each  revolving 
day,  and  the  hibernating  animal  at  some  period 
of  the  revolving  year.  We  have  thus  presented 
to  us  the  phenomena  of  diurnal  and  nocturnal 

*  Des  Agens  Physiques,  p.  155. 


animals,  and  the  winter-sleep  and  the  summer- 
sleep  of  hibernating  animals. 

Exposure  to  cold,  not  too  severe,  disposes  to 
hibernation,  as  it  disposes  to  ordinary  sleep. 
Severe  cold,  on  the  contrary,  first  rouses  the 
hibernating  animal  from  its  lethargy,  and  then 
plunges  this  and  all  animals  into  a  state  of  fatal 
torpor. 

The  absence  of  every  kind  of  stimulus  or  ex- 
citant, and  a  somewhat  confined  atmosphere,* 
also  conduce  to  hibernation. 

Every  excitement,  on  the  contrary,  that  of 
hunger,  that  of  the  sexes  probably,  tend  to  dis- 
turb this  peculiar  lethargy.  It  is  in  this  man- 
ner that  we  explain  the  periodicity  of  sleep  and 
hibernation,  though  there  is  probably  also  some 
hidden  influence  of  the  seasons,  of  the  day  or 
of  the  year,  influences  which  have  been  traced 
by  Dr.  Prout  and  by  M.  Edwards  in  regard 
to  the  quantity  of  respiration. 

I  now  proceed  to  treat  of  the  condition  of  the 
several  functions  in  hibernation. 

The  process  of  sanguification  is,  in  some 
hibernating  animals,  nearly  arrested  ;  in  others, 
it  is  entirely  so. 

There  is  much  difference  in  the  powers  of 
digestion,  and  in  the  fact  of  omitting  to  take 
food,  in  the  hibernation  of  different  animals. 
The  bat,  being  insectivorous,  would  awake  in 
vain ;  no  food  could  be  found  :  the  hedgehog 
might  obtain  snails  or  worms,  if  the  ground 
were  not  very  hard  from  frost :  the  dormouse 
would  find  less  difficulty  in  meeting  with  grain 
and  fruits.  We  accordingly  observe  a  remark- 
able difference  in  the  habits  of  awaking  from 
their  lethargy  or  hibernation,  in  these  different 
animals. 

I  have  observed  no  disposition  to  awake  at  all 
in  the  bat,  except  from  external  warmth  or  excite- 
ment. If  the  temperature  be  about  40°  or  45°, 
the  hedgehog,  on  the  other  hand,  awakes,  after 
various  intervals  of  two,  three,  or  four  days 
passed  in  lethargy,  to  take  food  ;  and  again  re- 
turns to  its  state  of  hibernation.  The  dor- 
mouse, under  similar  circumstances,  awakes 
daily. 

Proportionate  to  the  disposition  to  awake 
and  take  food,  is  the  state  of  the  functions  of 
the  stomach,  bowels  and  kidneys.  The  dor- 
mouse and  the  hedgehog  pass  the  faeces  and 
urine  in  abundance  during  their  intervals  of 
activity.  The  bat  is  scarcely  observed  to  have 
any  excretions  during  its  continued  lethargy. 

In  the  dormouse  and  the  hedgehog,  the  sense 
of  hunger  appears  to  rouse  the  animal  from  its 
hibernation,  whilst  the  food  taken  conduces  to 
a  return  of  the  state  of  lethargy.  It  has  already 
been  observed,  that  there  are  alternations  be- 
tween activity  and  lethargy  in  this  animal,  with 
the  taking  of  food,  in  temperatures  about  40° 
or  45°.  Nevertheless,  abstinence  doubtless  con- 
duces to  hibernation,  by  rendering  the  system 

*  M.  de  Saissy  observes,  "  la  marmotte,  que  j'ai 
engourdie  par  deux  fois  differentes,  ne  l'a  ete,  je 
crois,  que  parceque  je  me  suis  avise,  quand  la  re- 
spiration a  ete  bien  affaiblie,  de  boucher  le  trou  du 
couvercle.  Ce  n'a  ete  que  de  cette  maniere  que  je 
suis  parvenu  a  l'engourdir;  car  toutes  les  tentatives 
que  j'avais  faites  avant  out  ete  vaines." 


HIBERNATION. 


7G9 


more  susceptible  of  the  influence  of  cold,  in 
inducing  sleep  and  the  loss  of  temperature.  The 
hedgehog,  which  awakes  from  its  hibernation, 
and  does  not  eat,  returns  to  its  lethargy  sooner 
than  the  one  which  is  allowed  food. 

The  respiration  is  very  nearly  suspended  in 
hibernation.  That  this  function  almost  ceases, 
is  proved,  1st,  by  the  absence  of  all  detectible 
respiratory  acts  ;  2dly,  by  the  almost  entire  ab- 
sence of  any  change  in  the  air  of  the  pneuma- 
tometer ;  3dly,  by  the  subsidence  of  the  tem- 
perature to  that  of  the  atmosphere ;  and  4thly, 
by  the  capability  of  supporting,  for  a  great 
length  of  time,  the  entire  privation  of  air. 

1.  I  have  adopted  various  methods  to  ascer- 
tain the  entire  absence  of  the  acts  of  respiration. 
I  placed  bats  in  small  boxes,  divided  by  a  par- 
tition of  silk  riband,  the  cover  of  which  con- 
sisted of  glass,  and  in  the  side  of  which  a  small 
hole  was  made  to  admit  of  placing  a  long  light 
rod  or  feather  under  the  animal's  stomach.  The 
least  respiratory  movement  caused  the  extremity 
of  this  rod  to  pass  through  a  considerable  space, 
so  that  it  became  peifectly  apparent. 

Over  the  hibernating  hedgehog  I  placed  a 
similar  rod,  fixing  one  extremity  near  the  ani- 
mal, and  leaving  the  other  to  move  freely  over 
an  index.  During  hibernation  not  the  slightest 
movements  of  these  rods  could  be  observed, 
although  they  were  diligently  watched.  But 
the  least  touch,  the  slightest  shake  immediately 
caused  the  bat  to  commence  the  alternate  acts 
of  respiration,  whilst  it  invariably  produced  the 
singular  effect  of  a  deep  and  sonorous  inspira- 
tion in  the  hedgehog.  It  is  only  necessary  to 
touch  the  latter  animal  to  ascertain  whether  it 
be  in  a  state  of  hibernation  or  not :  in  the 
former  case  there  is  this  deep  sonorous  inspira- 
tion ;  in  the  latter,  the  animal  merely  moves 
and  coils  itself  up  a  little  more  closely  than 
before.  After  the  deep  inspiration,  there  are  a 
few  feeble  respirations, and  then  total  quiescence. 
The  bat  makes  similar  respirations  without  the 
deep  inspiration,  and  then  relapses  into  sus- 
pended respiration. 

2.  As  the  acts  of  respiration  are  nearly  sus- 
pended during  hibernation,  so  are  the  changes 
induced  in  the  atmospheric  air. 

On  January  the  28th,  the  temperature  of  the 
atmosphere  being  42°,  I  placed  a  bat  in  the 
most  perfect  state  of  hibernation  and  undis- 
turbed quiet,  in  the  pneumatometer,  during  the 
whole  night,  a  space  of  ten  hours,  from  lh.30m. 
to  llh.  30m.  There  was  no  perceptible  absorp- 
tion of  gas. 

Having  roused  the  animal  a  little,  I  replaced 
it  in  the  pneumatometer,  and  continued  to  dis- 
turb it  from  time  to  time,  by  moving  the  appa- 
ratus. It  continued  inactive,  and  between  the 
hours  of  lh.  20m.  and  4h.,  there  was  the  absorp- 
tion of  one  cubic  inch  only  of  gas. 

Being  much  roused  at  four  o'clock,  and  re- 
placed in  the  pneumatometer,  the  bat  now  con- 
tinued moving  about  incessantly  ;  in  one  hour, 
five  cubic  inches  of  gas  had  disappeared.  It 
was  then  removed.  A  further  absorption  took 
place  of  -8  of  a  cubic  inch  of  gas. 

Thus  the  same  little  animal,  which,  in  a  state 
of  hibernation,  passed  ten  hours  without  respi- 
ration, absorbed  or  converted  into  carbonic  acid, 

VOL.  II. 


5-8  cubic  inches  of  oxygen  gas  in  one  hour 
when  in  a  state  of  activity.  In  an  intermediate 
condition,  it  removed  one  cubic  inch  of  oxygen 
in  two  hours  and  forty  minutes. 

I  repeated  this  experiment  on  February  the 
18th.  A  bat,  in  a  state  of  perfect  hibernation, 
was  placed  in  the  pneumatometer,  and  remained 
in  it  during  the  space  of  twenty-four  hours. 
There  was  now  the  indication  of  a  very  slight 
absorption  of  gas,  not,  however,  amounting  to 
a  cubic  inch. 

On  February  the  22d,  I  repeated  this  expe- 
riment once  more,  continuing  it  during  the 
space  of  sixty  hours;  the  thermometer  de- 
scended gradually,  but  irregularly,  from  41°  to 
38°;  the  result  is  given  in  the  subjoined  table. 

External  Absorp-  Dura- 
Date  Temperature,  tion.  tion. 
Feb.  22     11  P.M  41° 

23  11  a.m  38$..**  "8  12h 

11  p.m  39±  -75  12 

24  11  a.m  38  ....  -5....  12 

11  p.m  39  ....'75  12 

25  11  a.m  38  -6  12 

3-4  60 

From  this  experiment  it  appears  that  3'4 
cubic  inches  of  oxygen  gas  disappeared  in  sixty 
hours,  from  the  respiration  of  a  bat  in  the  state 
of  lethargy.  It  has  been  seen  that  in  a  state  of 
activity,  an  equal  quantity  of  this  gas  disap- 
peared in  less  than  half  that  number  of  minutes. 
The  respiration  of  the  hibernating  bat  descends 
to  a  sub-reptile  state  ;  it  will  be  seen  shortly 
that  the  irritability  of  the  heart  and  of  the  mus- 
cular fibre  generally,  is  propoitionably  aug- 
mented. 

In  this  experiment  it  is  probable  that  the 
lethargy  of  the  animal  was  not  quite  complete. 
Should  the  temperature  of  the  atmosphere  fall, 
and  continue  at  32°,  I  shall  again  repeat  it 
under  these  circumstances.  The  respiration 
will  probably  be  still  mote  nearly  suspended. 

It  is  important  to  remark,  that  the  registra- 
tion of  the  quantity  of  absorption  in  these  expe- 
riments was  not  begun  until  several  hours  after 
the  animal  had  been  inclosed  within  the  jar  of 
the  pneumatometer,  so  that  the  absorption  of 
the  carbonic  acid  always  present  in  atmospheric 
air  was  excluded  from  the  result. 

It  may  be  a  question  whether  the  slight 
quantity  of  respiration  I  have  mentioned  be 
cutaneous.  The  absence  of  the  acts  of  respira- 
tion would  lead  us  to  this  opinion.  But  it  may 
be  observed,  that  these  acts  have  not  been 
watched,  and  can  scarcely  be  watched  continu- 
ously enough,  to  determine  the  question  of 
their  entire  absence.  Some  contrivance  to  as- 
certain whether  the  rod  has  moved  along  the 
index  daring  the  absence  of  the  observer  would 
resolve  every  doubt  upon  this  interesting  point. 
And  I  think  it  right  to  remark,  that  after  the 
apparent  total  cessation  of  respiration,  as  ob- 
served by  the  means  which  have  just  been  de- 
scribed, there  is  probably  still  a  slight  diaphrag- 
matic breathing.  I  am  led  to  this  conclusion, 
by  having  observed  a  slight  movement  of  the 
flank  in  a  favourable  light,  unattended  by  any 
motion  of  the  thorax  or  epigastrium. 

3.  Much  precaution  is  required  in  ascertain- 
3  £ 


770 


HIBERNATION. 


ing  the  comparative  temperature  of  the  animal 
with  that  of  the  atmosphere.  The  slightest  ex- 
citement induces  a  degree  of  respiration,  with 
the  consequent  evolution  of  heat. 

The  plan  which  is  best  adapted  to  determine 
this  question  in  regard  to  the  bat,  and  which  I 
have  adopted,  together  with  every  attention  to 
preserve  the  animal  quiet  and  undisturbed,  is 
the  following  :  a  box  was  made  of  mahogany, 
with  a  glass  lid,  divided  horizontally  at  its  mid- 
dle part,  by  a  fold  of  strong  riband,  and  of 


such  dimensions  as  just  to  contain  the  animal. 
The  bat  was  placed  upon  the  riband,  and  in- 
closed by  fixing  the  lid  in  its  place.  Being 
lethargic,  it  remained  in  undisturbed  quiet.  A 
thermometer,  with  a  cylindrical  bulb,  was  now 
passed  through  an  orifice  made  in  the  box  on  a 
level  with  the  riband,  under  the  epigastrium  of 
the  animal,  and  left  in  this  situation.  This 
arrangement  is  made  obvious  by  the  subjoined 
wood-cut,  (fig.  306,)  which  also  displays  the 
mode  of  examining  the  circulation. 


It  was  only  now  necessary  to  make  daily  ob- 
servations and  comparisons  between  this  ther- 
mometer and  another  placed  in  the  adjacent  at- 
mospheric air.  The  layer  of  silk,  and  the  por- 
tion of  air  underneath,  protected  the  animal 
from  the  immediate  influence  of  the  tempera- 
ture of  the  table,  on  which  the  box  was  placed. 

The  following  table  gives  the  result  of  obser- 
vations made  during  many  days,  in  very  vary- 
ing temperatures. 

Temperature  of  Temperature 
Date.  the  Atmosphere,  of  the  Animal. 

Jan.  6    11  p.m..  40  40 J 

7  8  p.m  43  43 

8   41  41^ 

9  11  p.m  47  46 

10  10  a.m  46  46 

—  12  midnight.  .47  47 

11  10  p.m  45  45 

12  11  p.m  45  45 

13  11  p.m  37  374 

14  11  a.m  37  37 

—  11  p.m  40  40 

15  2  p.m  37  37 

—  11  p.m  35  35 

16  11  p.m  37  37 

17  11  p.m  42  42 

18  11  a.m  40  40 

19  10  p.m  36  36 

20  11  p.m  39  39 

21  11  r.M  40  40 

22  11  p.m  44  44 

23  10  a.m  42§   424 

—  11  p.m  40§  404 

24  11  p.m  434   43| 

25  10  p.m  42  42 

26  10  p.m  41  41 

27  10  p.m  37  37 

28  11  a.m  344   344 

—  11  p.m  37  37 

29  11  a.m  42  42 

—  11  p.m  43  43 

30  11  p.m  42  42 

31  11  p.m  394  39i 


From  this  table  it  is  obvious  that  the  tempe- 
rature of  the  hibernating  animal  accurately  fol- 
lows that  of  the  atmosphere.  When  the  changes 
of  temperature  in  the  latter  are  slight,  the  two 
thermometers  denote  the  same  temperature.  If 
these  changes  are  greater  and  more  rapid,  the 
temperature  of  the  animal  is  a  little  lower  or 
higher,  according  as  the  external  temperature 
rises  or  falls ;  a  little  time  being  obviously  re- 
quired for  the  animal  to  attain  that  temperature. 

Similar  observations  were  made  during  the 
first  three  days  of  February.  On  the  4th,  how- 
ever, the  temperature  of  the  atmosphere  rose  to 
50§°;  that  of  the  animal  was  now  82°,  and  there 
was  considerable  restlessness.  On  the  6th,  the 
temperature  of  the  atmosphere  had  fallen  to 
474  ,  and  that  of  the  animal  to  48°,  whilst  there 
was  a  return  of  the  lethargy. 

After  this  period  there  were  the  same  equal 
alterations  of  temperature  in  the  animal  and  in 
the  atmosphere,  observed  in  the  month  of 
January. 

It  is  only  necessary  to  add  to  these  observa- 
tions, that  the  internal  temperature  is  about 
three  degrees  higher  than  that  of  the  epigas- 
trium. In  two  bats,  the  external  temperature 
of  each  of  which  was  36°,  a  fine  thermometer, 
with  an  extremely  minute  cylindrical  bulb, 
passed  gently  into  the  stomach,  rose  to  39°. 

The  following  experiments,  made  by  the 
celebrated  Jenner,  illustrate  this  point : 

"  In  the  winter,  the  atmosphere  at  44°,  the 
heat  of  a  torpid  hedgehog  at  the  pelvis  was  45°, 
and  at  the  diaphragm  48^°. 

"  The  atmosphere  26°,  the  heat  of  a  torpid 
hedgehog,  in  the  cavity  of  the  abdomen,  was 
reduced  so  low  as  30°. 

"  The  same  hedgehog  was  exposed  to  the 
cold  atmosphere  of  26°  for  two  days,  and  the 
heat  of  the  rectum  was  found  to  be  93°;  the 
wound  in  the  abdomen  being  so  small  that  it 
would  not  admit  the  thermometer.* 


*  The  animal  had  become  lively, 
on  the  Animal  (Economy,  p.  113. 


See  Hunter 


HIBERNATION. 


771 


"  A  comparative  experiment  was  made  with 
a  puppy,  the  atmosphere  at  50°;  the  heat  in 
the  pelvis,  as  also  at  the  diaphragm,  was  102°. 

"  In  summer,  the  atmosphere  at  78°,  the 
heat  of  the  hedgehog,  in  an  active  state  in  the 
cavity  of  the  abdomen,  towards  the  pelvis,  was 
95° ;  at  the  diaphragm,  97°."  * 

There  is  an  error  in  the  admirable  work  of 
M.  Edwards,  as  1  have  already  stated,  in  rela- 
tion to  the  present  subject,  which  it  is  important 
to  point  out.  M.  Edwards  first  ascertained  the 
interesting  fact,  that  the  very  young  of  those 
species  of  animals  which  are  born  blind,  lose 
their  temperature  if  removed  from  the  contact 
of  their  parent;  and  justly  concludes  that  they 
have  not  sufficient  power  of  evolving  heat,  to 
maintain  their  natural  temperature  when  so  ex- 
posed. M.  Edwards  then  subjected  hiberna- 
ting animals  to  the  action  of  cold,  and  observ- 
ing that  their  temperature  also  fell,  he  concludes 
that  they,  like  the  very  young  animal,  have  not 
the  faculty  of  maintaining  their  temperature 
under  ordinary  circumstances. f 

It  is  remarkable  that  this  acute  physiologist 
did  not  perceive  the  error  in  this  reasoning.  In 
no  instance  does  the  young  animal  maintain  its 
warmth,  when  exposed  alone  to  the  influence 
of  an  atmosphere  of  moderate  temperature. 
Can  this  be  said  of  the  hibernating  animal  ? 
Certainly  not.  In  ordinary  temperatures,  the 
hibernating  animal  maintains  its  activity,  and 
with  its  activity,  its  temperature.  The  loss  of 
temperature  in  this  kind  of  animal  is  an  in- 
duced condition,  occasioned  by  sleep. 

There  is  a  point  unnoticed  in  M.  Edwards's 
experiment.  It  is  the  condition  of  the  bat  in 
regard  to  activity  or  lethargy  under  the  exposure 
to  cold  ;  and  upon  this  the  whole  phenomena 
depend. 

The  differences  between  the  young  animal 
benumbed,  and  the  hibernating  animal  lethargic, 
from  cold,  are  both  great  and  numerous.  I 
purpose  to  point  them  out  particularly  on  a 
future  occasion. 

4.  It  is  in  strict  accordance  with  these  facts, 
that  the  lethargic  animal  is  enabled  to  bear  the 
total  abstraction  of  atmospheric  air  or  oxygen 
gas,  for  a  considerable  period  of  time. 

Spallanzani  placed  a  marmot  in  carbonic  acid 
gas,  and  makes  the  following  report  of  the  ex- 
periment in  a  letter  to  Senebier :  "  Vous  vous 
ressouviendrez  de  ma  marmotte  qui  fut  si  forte- 
ment  lethargique  dans  l'hiver  severe  de  1795  ; 
je  la  tins  alors  pendant  quatre  heures  dans  le 
gaz  acide  carbonique,  le  thermomitre  marquant 
— 12°,  elle  continua  de  vivre  dans  ce  gaz  qui 
est  le  plus  mortel  de  tous,  comme  je  vous  le 
disais :  au  moins  un  rat  et  un  oiseau  que  j'y 
placai  avec  elle  y  perirent  a  l'instant  meme.  11 
parait  done  que  sa  respiration  fut  suspendue 
pendant  tout  ce  terns-la.  Je  soumis  a  la  meme 
experience  des  chauve-souris  semblablement 
lethargiques,  et  le  resultat  fut  le  meme."  J 

*  Ibid.  p.  112. 

f  Des  Agens  Physiques,  p.  155. 

t  Memoires  sur  la  Respiration,  par  Lazare  Spal- 
lanzani, traduites  en  Fran<jais,  d'apris  son  manu- 
scrit  inedit,  par  Jean  Senebier,  p.  75. 


A  bat  which  was  lethargic  in  an  atmosphere 
of  36°  was  immersed  in  water  of  41°.  It  moved 
about  a  little,  and  expelled  bubbles  of  air  from 
its  lungs.  It  was  kept  in  the  water  during  six- 
teen minutes,  and  then  removed.  It  appeared 
to  be  uninjured  by  the  experiment. 

A  hedgehog  which  had  been  so  lethargic  in 
an  atmosphere  of  40°  as  not  to  awake  for  food 
during  several  days,  was  immersed  in  water  of 
42°.  It  moved  about  and  expelled  air  from  its 
lungs.  It  was  retained  under  the  water  during 
22J  minutes.  It  was  then  removed.  It  ap- 
peared uninjured. 

It  seems  probable  that  the  motions  observed 
in  these  animals  were  excited  through  the  me- 
dium of  the  cutaneous  nerves. 

The  power  of  supporting  the  abstraction  of 
oxygen  gas,  or  atmospheric  air,  belongs  solely 
to  the  hibernating  state,  and  is  no  property  of 
the  hibernating  animal  in  its  state  of  activity. 
After  having  found  that  the  dormant  bat,  in 
summer,  supported  immersion  in  water  during 
eleven  minutes,  uninjured,  I  was  anxious  to 
know  whether  the  active  hedgehog  possessed 
the  same  power.  I  immersed  one  of  these  ani- 
mals in  water.  It  expired  in  three  minutes, 
the  period  in  which  immersion  proves  fatal  to 
the  other  mammalia.  Sir  Anthony  Carlisle 
has,  therefore,  committed  an  error,  somewhat 
similar  to  that  of  M.  Edwards,  when  he  asserts 
that  "  animals  of  the  class  Mammalia,  which 
hibernate  and  become  torpid  in  winter,  have  at 
all  times  a  power  of  subsisting  under  a  confined 
respiration,  which  would  destroy  other  animals 
not  having  this  peculiar  habit."  *  The  power 
of  bearing  a  suspended  respiration  is  an  in- 
duced state.  It  depends  upon  sleep  or  lethargy 
themselves,  and  their  effect  in  impairing  or  sus- 
pending respiration ;  and  upon  the  peculiar 
power  of  the  left  side  of  the  heart,  of  becoming 
veno-contractile  under  these  circumstances. 

The  circulation  is  reduced  to  an  extreme  de- 
gree of  slowness,  according  to  a  law  well- 
known,  but  hitherto,  I  believe,  unexplained, 
according  to  which  the  respiration  and  the  cir- 
culation are  always  proportionate  to  each  other. 

The  wing  of  the  bat  affords  an  admirable  op- 
portunity of  observing  the  condition  of  the  cir- 
culation during  hibernation.  But  it  requires 
peculiar  management.  If  the  animal  be  taken 
from  its  cage,  and  the  wing  extended  under  the 
microscope,  it  is  roused  by  the  operation,  and 
its  respiratory  and  other  movements  are  so  ex- 
cited, that  all  accurate  observation  of  the  condi- 
tion of  the  circulation  in  the  minute  vessels  is 
completely  frustrated.  Still  greater  caution  is 
required  in  this  case  than  even  in  the  observa- 
tion of  the  respiration  and  temperature. 

After  some  fruitless  trials,  I  at  length  suc- 
ceeded perfectly  in  obtaining  a  view  of  the  mi- 
nute circulation  undisturbed.  Having  placed 
the  animal  in  its  state  of  hibernation,  in  a  little 
box  of  mahogany,  1  gently  drew  out  its  wing 
through  a  crevice  made  in  the  side  of  the  box ; 
I  fixed  the  tip  of  the  extended  wing  between 
portions  of  cork  ;  I  then  attached  the  box  and 
the  cork  to  a  piece  of  plate-glass ;  and  lastly,  I 

*  Phil.  Trans.  1805,  p.  17. 

3  e  2 


772 


HIBERNATION. 


left  the  animal  in  this  situation,  in  a  cold  atmo- 
sphere, to  resume  its  lethargy.  {See Jig.  306.) 

I  could  now  quietly  convey  the  animal  ready 
prepared,  and  place  it  in  the  field  of  the  micro- 
scrope  without  disturbing  its  slumbers,  and 
observe  the  condition  of  the  circulation. 

In  this  manner  1  have  ascertained  that, 
although  the  respiration  be  suspended,  the  cir- 
culation continues  uninterruptedly.  It  is  slow 
in  the  minute  arteries  and  veins ;  the  beat  of 
the  heart  is  regular,  and  generally  about  twenty- 
eight  times  in  the  minute. 

We  might  be  disposed  to  view  the  condition 
of  the  circulation  in  the  state  of  hibernation  as 
being  reptile,  or  analogous  to  that  of  the  batra- 
chian  tribes.  But  when  we  reflect  that  the  re- 
spiration is  nearly,  if  not  totally,  suspended, 
and  that  the  blood  is  venous,*  we  must  view 
the  condition  of  the  circulation  as  in  a  lower 
condition  still,  and,  as  it  were,  sub-reptile.  It 
may,  indeed,  be  rather  compared  to  that  state  of 
the  circulation  which  is  observed  in  the  frog  from 
which  the  brain  and  spinal  marrow  have  been 
removed  by  minute  portions  at  distant  inter- 
vals, f 

In  fact,  in  the  midst  of  a  suspended  respira- 
tion, and  an  impaired  condition  of  some  other 
functions,  one  vital  property  is  augmented. 
This  is  the  irritability,  and  especially  the  irrita- 
bility of  the  left  side  of  the  heart.  The  left 
side  of  the  heart,  which  is,  in  the  hibernating 
animal,  in  its  state  of  activity,  as  in  all  the 
other  mammalia,  only  arterio-contractile,  be- 
comes veno-contractile. 

This  phenomenon  is  one  of  the  most  remark- 
able presented  to  me  in  the  whole  animal  king- 
dom. It  forms  the  single  exception  to  the 
most  general  rule  amongst  animals  which  pos- 
sess a  double  heart.  It  accounts  for  the  possi- 
bility of  immersion  in  water  or  a  noxious  gas, 
without  drowning  or  asphyxia;  and  it  accounts 
for  the  possibility  of  a  suspended  respiration, 
without  the  feeling  of  oppression  or  pain, 
although  sensation  be  unimpaired.  It  is,  in  a 
word,  this  peculiar  phenomenon,  which,  con- 
joined with  the  peculiar  effect  of  sleep  in  in- 
ducing diminished  respiration  in  hibernating 
animals,  constitutes  the  susceptibility  and  capa- 
bility of  taking  on  the  hibernating  state.  On 
the  other  hand,  as  the  rapid  circulation  of  a 
highly  arterialized  blood  in  the  brain  and  spinal 
marrow  of  birds  probably  conduces  to  their 
activity,  the  slow  circulation  of  a  venous  blood 
doubtless  contributes  to  the  lethargy  of  the 
hibernating  animal. 

I  need  scarcely  advert  to  the  function  of 
defacation.  It  has  already  been  briefly  noticed 
under  the  head  of  sanguification,  with  which  it 
proceeds  pari  passu. 

In  regard  to  the  nervous  system,  I  can  only 
repeat  that  sensation  and  volition  are  quiescent. 

*  M.  Prunelle  observes,  "  En  comparant  le  sang 
de  deux  chauve-souris  auxquelles  j'avois  ouvert  les 
carotides,  a  l'une  pendant  son  engourdissement  et 
a  l'autre  dans  l'etat  de  veille,  j'ai  trouve  celui  de 
la  derniere  beaucoup  plus  vermeil."  Annales  du 
Museum,  tome  xviii.  p.  28. 

f  Essay  on  the  Circulation,  pp.  136-141. 


In  my  memoir  upon  the  subject  of  hibernation,* 
I  committed  an  error  relative  to  this  subject. 
But  I  am  now  satisfied  that  what  I  considered 
to  be  evidences  of  an  unimpaired  sensibility, 
were  phenomena  of  the  excito-motory  kind.  Thus 
I  have  observed  that  the  slighest  touch  applied 
to  one  of  the  spines  of  the  hedgehog  immedi- 
ately rouses  it  to  draw  that  deep  inspiration  of 
which  I  have  spoken.  The  merest  shake  in- 
duces a  few  respirations  in  the  bat.  The  least 
disturbance,  in  fact,  is  felt,  as  is  obvious  from 
its  effect  in  inducing  motion  in  the  animal. 

It  is  from  the  misconception  on  this  point 
that  the  error  has  arisen,  that  the  respiration  is 
not  absolutely  suspended  in  hibernation.  This 
function  has  been  so  readily  re-excited,  that  it 
has  been  considered  as  appertaining  to  the  state 
of  hibernation. 

As  I  have  already  stated,  the  cerebral  func- 
tions sleep,  the  true  spinal  functions  retain  their 
wonted  energy  ;  and  if  the  respiration  be  nearly 
suspended,  it  is  because  little  carbonic  acid,  the 
excitor  of  respiration,  is  evolved. 

In  the  midst  of  a  suspended  or  partially  sus- 
pended respiration,  the  irritability  of  the  mus- 
cular fibre  becomes  proportionately  augmented. 

The  single  fact  of  a  power  of  sustaining  the 
privation  of  air,  without  loss  of  life,  leads  alone 
to  the  inference  that  the  irritability  is  greatly 
augmented  in  the  state  of  hibernation.  This 
inference  flows  from  the  law  already  stated, 
and  the  fact  is  one  of  its  most  remarkable  illus- 
trations and  confirmations. 

It  might  have  been  inferred  from  these  pre- 
mises, that  the  beat  of  the  heart  would  continue 
longer  after  decapitation  in  the  state  of  hiber- 
nation than  in  the  state  of  activity  in  the  same 
animal ;  an  inference  at  once  most  singular  and 
correct. 

This  view  receives  the  fullest  confirmation 
from  the  following  remarkable  experiment:  on 
March  the  9th,  soon  after  midnight,  I  took  a 
hedgehog  which  had  been  in  a  state  of  uninter- 
rupted lethargy  during  150  hours,  and  divided 
the  spinal  marrow  just  below  the  occiput;  I 
then  removed  the  brain  and  destroyed  the 
whole  spinal  marrow  as  gently  as  possible. 
The  action  of  the  heart  continued  vigorous 
during  four  hours,  when,  seeing  no  prospect  of 
a  termination  to  the  experiment,  I  resolved  to 
envelope  the  animal  in  a  wet  cloth,  and  leave 
it  until  early  in  the  morning.  At  7  o'clock 
a.m.  the  beat  of  both  sides  of  the  heart  still 
continued.  They  still  continued  to  move  at 
10  a.m.,  each  auricle  and  each  ventricle  con- 
tracting quite  distinctly.  At  half-after  1 1  a.m. 
all  were  equally  motionless  ;  yet  all  equally 
contracted  on  being  stimulated  by  the  point  of 
a  penknife.  At  noon  the  two  ventricles  were 
alike  unmoved  on  being  irritated  as  before;  but 
both  auricles  contracted.  Both  auricles  and 
ventricles  were  shortly  afterwards  unirritable. 

This  experiment  is  the  most  extraordinary  of 
those  which  have  been  performed  upon  the 
mammalia.  It  proves  several  interesting  and 
important  points  :  1.  That  the  irritability  of  the 
heart  is  augmented  in  continued  lethargy  in  an 

*  Phil.  Trans,  for  1832. 


HIBERNATION. 


773 


extraordinary  degree.  2.  That  the  irritability 
of  the  left  side  of  the  heart  is  then  little,  if  at 
all,  less  irritable  than  the  right, — that  it  is,  in 
fact,  veno-contractile.  3.  That,  in  this  condi- 
tion of  the  animal  system,  the  action  of  the 
heart  continues  for  a  considerable  period  inde- 
pendently of  the  brain  and  spinal  marrow. 

On  April  the  20th,  at  six  o'clock  in  the  even- 
ing, the  temperature  of  the  atmosphere  being 
53°,  a  comparative  experiment  was  made  upon 
a  hedgehog  in  its  state  of  activity :  the  spinal 
marrow  was  simply  divided  at  the  occiput;  the 
beat  of  the  right  ventricle  continued  upwards 
of  two  hours,  that  of  the  left  ventricle  ceased 
almost  immediately ;  the  left  auricle  ceased  to 
beat  in  less  than  a  quarter  of  an  hour;  the  right 
auricle  also  ceased  to  beat  long  before  the  right 
ventricle. 

In  further  proof  of  the  same  fact,  I  may  here 
adduce  a  remarkable  paragraph  from  the  paper 
of  Mangili  in  the  Annales  du  Museum:* 
"  J'observai  a.  peu  pres  les  memes  choses  dans 
tine  autre  marmotte  en  lethargie,  que  je  deca- 
pitai  le  22  de  Mars  1807.  Mais  en  ouvrant 
celle-ci,  j'avois  deux  objets  :  le  premier,  d'ex- 
aminer  l'etat  des  visceres  les  plus  importans, 
comme  le  cceur,  les  poumons  et  le  cerveau.  Le 
second  etoit  de  voir  comment  procedent  les 
phenomenes  de  l'irritabilite  musculaire ;  parce 
qu'ayant  entendu  dire  a  un  celebre  naturaliste, 
que  l'engourdissement  avoit  pour  cause  Taltera*- 
tion  ou  la  suspension  de  cette  irritabilite,  jV 
m'importoit  de  savoir  si  cette  assertion  etcyt 
vraie.  Dans  la  chambre  ou  se  trouvoit  la  mar-' 
motte,  le  thermometre  etoit  a  6  degres  et  demi.^ 
1'ayant  introduit  dans  le  bas  ventre,  il  monta 
d'un  degre,  c'est-a-dire  a  7  degres  et  demi.  „ 

"  Je  trouvai  les  poumons  dans  leur  etat  na- 
turel.  Le  coeur  continua  a  battre  pendant  plus 
de  trois  heures.  Les  pulsations,  d'abord  vives 
et  frequentes,  s'afToiblirent  et  se  ralentirent  peur- 
a-peu.  J'enavois  compte  de  seize  a  dix-huit 
par  minute  au  commencement  de  la  premiere 
heure ;  a  la  fin  de  la  troisieme  je  n'en  comptois 
plus  que  trois  dans  le  meme  temps.  Les 
veines  du  cerveau  me  parurent  gonflees  de 
sang. 

"  La  tete  unie  au  cou  ayant  ete  separee  du 
tronc,  je  la  mis  dans  un  vase  avec  de  Tesprit- 
de-vin,  et  j'y  remarquai,  meme  apres  une  demi- 
heure,  des  mouvemens  assez  sensibles.  Ce  fait 
prouve,  ainsi  que  plusieurs  autres  dont  je  par- 
lerai  bien  tot,  que  si  dans  l'etat  de  lethargie 
conservatrice  la  vie  est  beaucoup  moins  ener- 
gique,  le  principe  vital  repandu  dans  les  diver- 
ses  parties,  a  beaucoup  plus  de  tenacite,  et 
tarde  bien  plus  a  s'eteindre. 

"  Je  separai  du  corps  de  l'animal  plusieurs 
morceaux  des  muscles  qui  obeissent  a  la  vo- 
lonte,  et  je  vis  avec  etonnement  que,  trois 
heures  apres  la  mort,  ils  se  contractoient  forte- 
ment  chaque  fois  que  je  les  soumettois  a  Tac- 
tion galvanique.  Ces  mouvemens  convulsifs 
ne  se  ralentirent  qu'au  bout  de  quatre  heures. 

"  II  suit  de  la  que  les  marmottes  tuees  pen- 
dant qu'elles  sont  en  lethargie,  presentent,  rela- 
tivement  a  1'irritabilitc,  a  peu  pres  les  memes 

*  Tome  x.  p.  453-456. 


phenomenes  qu'on  remarque  dans  plusieurs 
animaux  a  sang  froid. 

"  Pour  savoir  ensuite  si  les  phenomenes  d'ir- 
ritabihte  etoient  les  memes  dans  l'etat  de  veille 
et  dans  celui  de  lethargie,  le  25  de  Juin,  j'ai 
fait  perir,  precisement  de  la  meme  mamere, 
une  seconde  marmotte  qui  etoit  eveillee  depuis 
deux  mois,  et  qui  faisoit  de  frequentes  courses 
dans  le  jardin.  Mon  thermomfetre  marquoit 
ce  jour-la  18  degres:  1'ayant  introduit  dans  le 
ventre  de  la  marmotte  au  moment  ou  je  venois 
de  la  decapiter,  il  s'eleva  a  29  degres. 

"  Ayant  mis  le  cceur  a  decouvert,  comme  je 
1'avois  fait  dans  mon  experience  du  mois  de 
Mars,  je  comptai  d'abord  vingt-sept  ou  vingt- 
huit  pulsations  par  minute.  Ce  nombre  n 'etoit 
plus  que  de  douze  au  bout  d'un  quart  d'heure, 
et  de  huit,  au  bout  de  demi-heure :  dans  le  dix 
minutes  suivantes,  il  n'y  eut  plus  que  quatre 
qjulsations  tres-foibles  par  minute,  et  elles  ces- 
serent  totalement  dans  les  dix  dernieres  minutes, 
c'est-a-dire  cinquante  minutes  apres  la  mort  de 
l'animal;  tandis  que  le  cceur  de  la  marmotte 
tuee  dans  l'etat  de  lethargie,  donnoit  encore 
quatre  legeres  pulsations  par  minute,  trois 
heures  apres  que  la  tete  avoit  ete  separee  du 
corps.  Cette  grande  difference  prouve  que  le 
principe  de  l'irritabilite  s'accuinule  pendant  la 
lethargie  conservatrice. 

"  Les  chairs  musculaires  me  semblirent  plus 
pales  que  celles  de  la  marmotte  en  lethargie  : 
elles  etoient  d'abord  tres  sensibles  a  Taction 
galvanique;  mais  ses  signes  d'lrritabilite  s'afToi- 
blirent et  disparurent  bien  plus  rapidement. 
En  effet,  les  chairs  musculaires  de  cette  mar- 
motte etoient  peu  sensibles  au  bout  de  deux 
heures,  tandis  que  dans  la  marmotte  tuee  en 
hiver  elles  se  contractoient  fortement  au  bout 
de  trois  heures,  et  que  1'irritabilitc  ne  s'affoiblit 
notablement  que  quatre  heures  apres  la  mort. 

"  Les  chairs  des  muscles  intercostaux  et 
abdominaux  conserverent  leur  sensibilite  au 
stimulus  eleetrique  quelques  minutes  de  plus 
que  celles  des  membres  ;  d'ou  Ton  peut  con- 
clure  que  le  principe  de  l'irritabilite  se  conserve 
d'avantage  dans  certaines  parties  du  meme  ani- 
mal. Mais  ce  qui  est  prouve  jusqu'a  Tevidence, 
c'est  que  ce  principe  a  bien  plus  de  tenacite 
dans  les  chairs  de  l'animal  tue  pendant  l'etat 
de  lethargie,  que  dans  celles  de  l'animal  tiie" 
pendant  l'etat  de  veille." 

This  author  does  not  appear  to  have  had  any 
apprehension  of  the  extreme  importance  of  this 
extraordinary  change  in  the  irritability,  but 
merely  states  it  as  a  fact.  Its  due  value  can 
only  be  known  by  observing  the  dependence  of 
the  functions  of  life  on  that  law  of  the  inverse 
condition  of  the  respiration  and  of  the  irritabi- 
lity, of  which  so  much  has  already  been  said. 
In  the  hibernating  animal  the  respiration  is 
nearly  suspended  ;  had  not  the  irritability  be- 
come proportionately  augmented,  the  actions  of 
life  must  have  ceased  !  , 

I  must  add  one  remark  upon  the  motility  of 
the  muscular  fibre  in  hibernation  ;  it  is  unim- 
paired. Those  physiologists  who  have  asserted 
the  contrary,  have,  as  will  be  shown  shortly, 
mistaken  the  phenomena  of  torpor  from  cold, 
for  those  of  true  hibernation. 


774 


HIBERNATION. 


If  the  hedgehog  in  a  state  of  the  most  perfect 
lethargy,  uncomplicated  with  torpor,  be  touched, 
its  respiration  is  resumed,  and  it  coils  itself  up 
more  forcibly  than  before.  The  dormouse,  in 
similar  circumstances,  unfolds  itself;  and  the 
bat  moves  variously.  Not  the  slightest  stiffness 
is  observed.  The  hedgehog,  when  roused,  walks 
about,  and  does  not  stagger,  as  has  been  asserted . 
The  bat  speedily  takes  to  the  wing,  and  flies 
about  with  great  activity,  although  exhaustion 
and  death  may  subsequently  result  from  the 
experiment.  The  phenomena  are  similar  to 
those  of  awaking  from  natural  sleep.  Impaired 
motility,  stiffness,  lameness,  &c.  belong  to  tor- 
por, and  not  to  true  hibernation. 

III.  Of  reviviscence. —  Not  the  least  inte- 
resting of  the  phenomena  connected  with  hiber- 
nation are  those  of  reviviscence.  Hibernation 
induces  a  state  of  irritability  of  the  left  side  of 
the  heart,  which,  with  high  respiration  and  an 
arterialized  blood,  would  be  incompatible  with 
life.  Respiration  suddenly  restored,  and  per- 
manently excited,  is,  therefore,  as  destructive  as 
its  privation  in  other  circumstances. 

All  those  bats  which  were  sent  to  me  from 
distant  parts  of  the  country  died.  The  conti- 
nued excitement  from  the  motion  of  the  coach 
keeping  them  in  a  state  of  respiration,  the  ani- 
mal perished.  One  bat  had,  on  its  arrival, 
been  roused  so  as  to  fly  about.  Being  left 
quiet,  it  relapsed  into  a  state  of  hibernation. 
The  excitement  being  again  repeated  the  next 
day,  it  again  flew  about  the  room ;  on  the  suc- 
ceeding day  it  was  found  dead. 

It  is  in  accordance  with  this  law,  that  we 
observe  hibernating  animals  adopting  various 
measures  to  secure  themselves  from  frequent 
sources  of  disturbance  and  excitement.  They 
choose  sheltered  situations,  as  caverns,  burrows, 
&c.  secure  from  the  rapid  changes  and  the  in- 
clemencies of  the  weather  and  season.  Many 
form  themselves  nests;  others  congregate  toge- 
ther. The  hedgehog  and  the  dormouse  roll 
themselves  up  into  a  ball.  The  common  bat 
suspends  itself  by  the  claws  of  its  hinder  feet, 
with  its  head  dependent,  generally  in  clusters  ; 
the  horseshoe  bat  (ferritin  equinum )  spreads  its 
wings  so  as  to  embrace  and  protect  its  fellows. 

All  these  circumstances  are  obviously  de- 
signed to  prevent  disturbed  hibernation. 

In  the  depth  of  caverns,  and  other  situations 
sheltered  from  changes  of  temperature  in  the 
atmosphere,  the  calls  of  hunger  are  probably 
the  principal  cause  of  reviviscence  in  the  spring. 
The  other  causes  of  reviviscence  are  the  return 
of  warmth  and  external  excitements  :  it  is  inte- 
resting to  observe  and  trace  the  gradual  return 
of  respiration  in  the  former  case,  and  of  the 
temperature  of  the  animal  in  the  latter. 

If  the  hibernating  hedgehog  be  touched  even 
very  gently,  it  draws  a  deep  breath,  and  then 
continues  to  breathe  for  a  short  time.  If  this 
excitement  be  repeated,  the  animal  is  perma- 
nently roused,  and  its  temperature  raised.  If 
the  temperature  of  the  atmosphere  be  augment- 
ed, the  respiration  is  gradually  excited,  and  the 
animal  is  gradually  restored  to  its  state  of 
activity. 

If  a  hibernating  animal  be  excited  in  a  very 


cold  atmosphere,  its  temperature  rises  variously, 
and  then  falls.  A  bat  was  perfectly  lethargic 
in  a  temperature  of  36°.  A  fine  thermometer, 
with  a  cylindrical  bulb,  was  introduced  into  its 
stomach ;  it  rose  to  39°.  One  hour  after- 
wards, the  animal  not  being  further  disturbed, 
the  respiration  was  rapid,  and  the  temperature 
in  the  stomach  95°.  Shortly  afterwards  the 
temperature  was  90°.  The  minute  circulation 
was  pretty  good,  and  pulsatory  in  the  arteries, 
the  heart  beating  from  twenty-eight  to  thirty- 
six  times  in  the  minute. 

In  another  bat,  in  an  atmosphere  of  the  tem- 
perature of  36°,  the  thermometer  in  the  stomach 
rose  to  39°.  The  animal  being  continually  ex- 
cited, the  temperature  rose  to  65°,  but  speedily 
fell  to  60°. 

The  animal  excited  and  revived  in  this  man- 
ner is  in  a  state  of  exhaustion  and  inanition.  It 
is  incapable  of  maintaining  its  temperature  if 
exposed  to  cold,  and  will  die  unless  it  repass 
into  the  state  of  hibernation.  It  may  be  com- 
pared to  the  case  of  the  mouse  deprived  of  food 
in  the  following  experiment  of  Mr.  Hunter. 
"  A  mouse  was  put  into  a  cold  atmosphere  of 
13°  for  an  hour,  and  then  the  thermometer  was 
introduced  as  before  ;  but  the  animal  had  lost 
heat,  for  the  quicksilver  at  the  diaphragm  was 
carried  only  to  83°,  in  the  pelvis  to  78°. 

"  In  order  to  determine  whether  an  animal 
that  is  awakened  has  the  same  powers,  with 
respect  to  preserving  heat  and  cold,  as  one  that 
is  vigorous  and  strong,  I  weakened  a  mouse  by 
fasting,  and  then  introduced  the  bulb  of  the 
thermometer  into  its  belly ;  the  bulb  being  at 
the  diaphragm,  the  quicksilver  rose  to  97°;  in 
the  pelvis  to  95°,  being  two  degrees  colder  than 
the  strong  mouse  :  the  mouse  being  put  into 
an  atmosphere  as  cold  as  the  other,  and  the 
thermometer  again  introduced,  the  quicksilver 
stood  at  79°  at  the  diaphragm,  and  at  74°  in 
the  pelvis. 

"  In  this  experiment  the  heat  at  the  dia- 
phragm was  diminished  18°,  in  the  pelvis  21°. 

"  This  greater  diminution  of  heat  in  the 
second  than  in  the  first,  we  may  suppose  pro- 
portional to  the  decreased  power  of  the  animal, 
arising  from  want  of  food."* 

But  extreme  cold  alone,  by  a  painful  effect 
induced  on  the  sentient  nerves,  rouses  the 
hibernating  animal  from  its  lethargy,  as  has 
been  remarked  already,  and  is  illustrated  by  the 
following  experiments  of  Hunter.  "  Having 
brought  a  healthy  dormouse,  which  had  been 
asleep  from  the  coldness  of  the  atmosphere, 
into  a  room  in  which  there  was  a  fire,  (the 
atmosphere  at  64°,)  I  introduced  the  thermo- 
meter into  its  belly,  nearly  at  the  middle,  be- 
tween the  thorax  and  pubis,  and  the  quicksilver 
rose  to  74°  or  75° ;  turning  the  bulb  towards 
the  diaphragm,  it  rose  to  80° ;  and  when  I  ap- 
plied it  to  the  liver,  it  rose  to  81  §°. 

"  The  mouse  being  placed  in  an  atmosphere 
at  20°,  and  left  there  half  an  hour,  when  taken 
out  was  very  lively,  even  much  more  so  than 
when  put  in.  Introducing  the  thermometer 
into  the  lower  part  of  the  belly,  the  quicksilver 

*  Animal  (Economy,  pp.  114,  115. 


HIBERNATION. 


775 


rose  to  91°;  and  turning  it  up  to  the  liver,  to 
93°. 

"  The  animal  being  replaced  in  the  cold 
atmosphere  at  30°,  for  an  hour,  the  thermome- 
ter was  again  introduced  into  the  belly  ;  at  the 
liver  it  rose  to  93°;  in  the  pelvis  to  92°;  the 
mouse  continuing  very  lively. 

"  It  was  again  put  back  into  an  atmosphere 
cooled  to  1 9°,  and  left  there  an  hour ;  the  ther- 
mometer at  the  diaphragm  was  87°;  in  the 
pelvis  83°;  but  the  animal  was  now  less 
lively. 

"  Having  been  put  into  its  cage,  the  thermo- 
meter being  placed  at  the  diaphragm,  in  two 
hours  afterwards  was  at  93°."  * 

In  these  experiments  the  animals  appear  to 
have  been  roused  partly  by  the  state  of  the 
wound  in  the  abdomen,  but  chiefly  by  the  ex- 
treme cold.  They  can  scarcely,  however,  be 
considered  as  experiments  upon  hibernation, 
however  interesting  they  may  be  in  reference  to 
reviviscence  from  that  state. 

The  fact  of  the  fatal  influence  of  excited  re- 
spiration during  the  augmented  irritability  of 
hibernation,  contrasted  with  the  similar  fatal 
effect  of  suspended  respiration,  during  the  dimi- 
nished irritability  of  the  state  of  activity,  will 
illustrate  many  of  the  causes,  kinds,  and  phe- 
nomena of  death.  Do  not  these  resolve  them- 
selves, in  fact,  into  irritability  insufficiently  or 
excessively  excited  ? 

IV.  Of  torpor  from  cold. — It  is  highly  im- 
portant, and  essential  to  the  present  investiga- 
tion to  distinguish  that  kind  of  torpor  which 
may  be  produced  by  cold  in  any  animal,  from 
true  hibernation,  which  is  a  property  peculiar 
to  a  few  species.  The  former  is  attended  by  a 
benumbed  state  of  the  sentient  nerves,  and  a 
stiffened  condition  of  the  muscles  ;  it  is  the 
direct  and  immediate  effect  of  cold,  and  even 
in  the  hibernating  animal  is  of  an  injurious  and 
fatal  tendency;  in  the  latter,  the  sensibility  and 
motility  are  unimpaired,  the  phenomena  are 
produced  through  the  medium  of  sleep;  and 
the  effect  and  object  are  the  preservation  of 

Striking  as  these  differences  are,  it  is  certain 
that  the  distinction  has  not  always  been  made 
by  former  observers.  In  all  the  experiments 
which  have  been  made,  with  artificial  tempera- 
tures especially,  it  is  obvious  that  this  distinc- 
tion has  been  neglected. 

True  hibernation  is  induced  by  temperatures 
only  moderately  low.  All  hibernating  animals 
avoid  exposure  to  extreme  cold.  They  seek 
some  secure  retreat,  make  themselves  nests  or 
burrows,  or  congregate  in  clusters,  and,  if  the 
season  prove  unusually  severe,  or  if  their  retreat 
be  not  well  chosen  and  they  be  exposed  in  con- 
sequence to  excessive  cold,  many  become  be- 
numbed, stiffen,  and  die. 

In  our  experiments  upon  hibernation  we 
should  imitate  nature's  operations.  Would  any 
one  imagine  that  the  following  detail  contained 
the  account  of  an  experiment  upon  this  sub- 
ject ?  "  Le  31  Janvier,"  says  M.  Saissy,  "  a 
trois  heures  du  soir,  la  temperature  atmosphe- 

*  Animal  (Economy,  pp.  Ill,  112. 


rique  e"tant  a  l°-25  au-dessous  de  zero,  celle 
d'un  herisson  engourdi  profondement  a  3°'50 
au  dessus,  j'enfermai  ce  quadrupede  dans  un 
bocal  de  verre  entoure  de  toute  part  d'une  mix- 
tion de  glace  et  de  muriate  de  soude.  L'exc£s 
du  froid  le  reveilla  d'abord,  mais  trois  heures 
ont  suffi  pour  le  replonger  dans  une  profonde 
torpeur. 

"  J'avais  place  l'animal  de  maniere  que  je 
pouvais  repeter,  autant  que  je  le  jugeais  neces- 
saire,  les  experiences  thermom^tnques.  Des 
que  sa  temperature  eut  baisse  jusqu'a  zero,  (ce 
ne  fut  qu'a  2  heures  du  matin)  je  le  retirai  du 
bocal  et  le  placai  dans  une  temperature  de  12° 
et  plus  au  dessus  de  la  glace ;  mais  l'animal 
ctait  mort."  * 

To  induce  true  hibernation,  it  is  quite  neces- 
sary to  avoid  extreme  cold  ;  otherwise  we  pro- 
duce the  benumbed  and  stiffened  condition  to 
which  the  term  torpor  or  torpidity  may  be 
applied.  I  have  even  observed  that  methods 
which  secure  moderation  in  temperature,  lead 
to  hibernation  :  hedgehogs,  supplied  with  hay 
or  straw,  and  dormice,  supplied  with  cotton- 
wool, make  themselves  nests  and  become  lethar- 
gic ;  when  others,  to  which  these  materials  are 
denied,  and  which  are  consequently  more  ex- 
posed to  the  cold,  remain  in  a  slate  of  activity. 
In  these  cases,  warmth  or  moderated  cold  ac- 
tually concur  to  produce  hibernation. 

When  we  read  of  insensibility,  of  a  stiffened 
state  of  the  muscles,  and  of  a  cessation  of  the 
circulation,  as  obtaining  in  hibernation,  we  may 
be  certain  that  a  state  of  torpor  has  been  mis- 
taken for  that  condition.  The  actually  hiber- 
nating animal  exposed  to  continued  severe  cold 
is,  as  M.  Saissy  correctly  observes,  first  roused 
from  this  state  of  ease  and  preservation  into  a 
painful  activity,  and  then  plunged  into  a  fatal 
torpor. 

This  subject  will  come  to  be  considered  in  a 
subsequent  part  of  this  inquiry,  in  which  I 
purpose  to  trace  the  effects  of  cold  in  changing 
the  relative  quantity  of  respiration  and  degree 
of  the  irritability  in  animals  of  different  ages 
which  do  not  hibernate;  in  the  meantime,  the 
accurate  distinction  between  mere  torpor,  which 
may  occur  in  any  animal,  and  which  is  a  de- 
structivestate,  from  true  hibernation,  which  is 
preservative,  and  the  peculiarity  of  certain  ani- 
mals, will  enable  us  to  correct  many  inaccuracies 
into  which  Legallois,f  M.  Edwards, \  and  other 
physiologists  have  fallen.  (See  Irritability.) 

In  conclusion,  one  of  the  most  general  effects 
of  sleep  is  to  impair  the  respiration,  and  with 
that  function  the  evolution  of  animal  tempera- 
ture. The  impaired  state  of  the  respiration  in- 
duces a  less  arterial  condition  of  the  blood, 
which  then  becomes  unfit  for  stimulating  the 
heart;  accumulation  of  the  blood  takes  place 
in  the  pulmonary  veins  and  left  auricle ;  a 
sense  of  oppression  is  induced,  and  the  animal 
is  either  roused  to  draw  a  deep  sigh  or  awakes 
altogether. 

*  Recherchcs  sur  Ics  Animaux  hibernans,  par 
M.  J.  A.  Saissy,  pp.  13,14. 

+  (Euvrcs  de  Legallois,  I'aris,  1824,  p.  282. 
X  Agcns  I'hysiqtics,  pp.  148,  292. 


776  NORMAL  ANATOMY  OF  THE  HIP-JOINT. 


Such  are  the  phenomena  in  animals  in  which 
the  heart  has  not  the  faculty  of  taking  on  an 
augmented  state  of  irritability,  with  this  lessened 
degree  of  stimulus.  But  in  those  animals  which 
do  possess  this  faculty,  a  property  which  con- 
stitutes the  power  of  hibernation,  the  heart  con- 
tinues the  circulation  of  the  blood,  more  slowly 
indeed,  but  not  less  perfectly,  although  its  arte- 
rial character  be  diminished  and  its  stimulant 
property  impaired.  No  repletion  of  the  pul- 
monary veins  and  of  the  left  auricle,  no  sense 
of  oppression  is  induced,  and  the  animal  is  not 
roused  ;  the  respiration  continues  low,  the  tem- 
perature falls,  and  the  animal  can  bear,  for  a 
short  period,  the  abstraction  of  atmospheric  air. 

All  the  phenomena  of  hibernation  originate, 
then,  in  the  susceptibility  of  augmented  irritabi- 
lity. The  state  of  sleep,  which  may  be  viewed 
as  the  first  stage  of  hibernation,  induces  an  im- 
paired degree  of  respiration.  This  would  soon 
be  attended  with  pain,  if  the  irritability  of  the 
heart  were  not  at  the  same  time  augmented,  so 
as  to  carry  on  the  circulation  of  a  less  arterial 
blood,  and  the  animal  would  draw  a  deep  sigh 
— would  augment  its  respiration  or  awake. 
Occasional  sighs  are,  indeed,  observed  in  the 
sleep  of  all  animals,  except  the  hibernating.  In 
these,  the  circulation  goes  on  uninterruptedly, 
with  a  diminished  respiration,  by  the  means  of 
an  augmented  irritability.  There  is  no  stagna- 
tion of  the  blood  at  the  heart ;  consequently,  no 
uneasiness ;  and  the  animal  becomes  more  and 
more  lethargic,  as  the  circulation  of  a  venous 
blood  is  more  complete.  This  lethargy  is  even- 
tually interrupted  by  circumstances  which  break 
ordinary  sleep,  as  external  stimuli  or  the  calls 
of  appetite. 

It  still  remains  for  me  briefly  to  discuss  the 
question, — what  are  the  hibernating  animals? 
I  must  first  advert  to  the  fact,  on  which  I  have 
already  insisted,  that  hibernation  does  not  pre- 
sent itself  in  an  equal  degree  in  all  the  hiber- 
nating tribes.  All  animals  sleep  periodically, 
in  the  night  or  in  the  day.  Some  sleep  for 
several  days  together,  especially  after  taking 
food,  and  in  the  cool  seasons  of  the  year,  as  the 
hedgehog.  Perhaps  the  bat  may  be  the  only 
animal  which  sleeps  profoundly  the  winter 
through,  without  awaking  to  take  food. 

These  remarks  prepare  us  for  a  more  just 
view  of  hibernation  and  of  hibernating  animals 
than  is,  as  I  believe,  usually  taken. 

Of  the  hibernating  animals  the  most  unequi- 
vocal are  the  bat,  the  hedgehog,  the  marmot, 
the  hamster,  the  dormouse.  It  has  been  said 
that  the  bear  and  beaver  belong  to  the  num- 
ber, but  this  is  extremely  doubtful.  It  has 
been  said  also  that  the  swallow  belongs  to  the 
hibernating  class,  but  this  is  incorrect.  The 
cold-blooded  animals,  the  Chelonian,  the  Sau- 
rian, the  Ophidian,  and  the  Batrachian  tribes, 
all,  however,  indubitably  pass  the  winter  in  a 
state  of  apathy  and  lethargy.  Some  of  the 
fishes  also  become  lethargic  during  the  cold 
season.  The  same  remark  applies  to  some  of 
the  molluscous  and  insect  tribes. 

Bibmogk  4PHY.  —Hunter,  An. (Economy,  Owen's 
edition,  p.  131.    Lond.  1837.     Spallanzani,  Mem. 


sur  la  Respiration,  par  Senebier.  Genev.  1803; 
or  Eng.  translat.  Edinb.  1804.  De  Saisxy,  Re- 
cherchesexp.  surles  Anim.  Hi vernans., Lyons,  1808. 
Mangili,  Essai  sur  la  Lethargie  periodique.  Milan, 
1807.  Edwards,  sur  les  Agens  Physiques.  Paris, 
1824,  or  Dr.  Hodgkin's  English  transl.  Prunelle, 
Recherches  sur  les  phenom.  et  sur  les  causes  du 
sommeil  hivernal.  Ann.  du  Mus.  t.  xviii.  Berthuld, 
Miiller's  Archiv.  1837,  p.  67.  Muller's  Physiology, 
passim. 

(Marshall  Hall.) 

HIP-JOINT,  NORMAL  ANATOMY 
OF  (in  human  anatomy). — Fr.  articulation 
ilio-femorale  ;  Germ.  Huj't  gelenk. — This  joint 
belongs  to  the  class  of  enarthrodial  or  ball  and 
socket  joints,  being  formed  by  the  adaptation 
of  the  head  of  the  femur  to  the  acetabulum  of 
the  os  innominatum.  These  bones  are  con- 
nected by  a  very  powerful  capsular  ligament, 
which  again  is  completely  covered  by  strong 
and  thick  muscles,  under  the  influence  of  which 
the  various  motions  of  the  joint  are  performed. 
We  propose  to  examine  seriatim  the  several 
textures  entering  into  the  formation  of  this 
joint,  and  lastly  to  consider  the  motions  of 
which  it  is  susceptible. 

The  bones. — Of  the  two  bones  which  in  the 
adult  enter  into  the  formation  of  this  joint,  the 
os  innominatum  contributes  by  the  acetabulum, 
and  the  femur  by  its  head. 

The  acetabulum  (cotyloid  cavity  :  Germ,  die 
Pj'anne)  is  the  cup  or  socket  which  receives  the 
head  of  the  femur,  and  is  admitted  to  be  the 
deepest  articular  cavity  in  the  body.  Prior  to 
the  adult  period  of  life  this  cavity  serves  as 
the  centre  of  union  for  the  three  bones  of 
which  the  os  innominatum  is  formed,  viz.,  the 
ilium,  ischium,  and  pubis.  These,  however, 
do  not  enter  equally  into  the  acetabulum,  inas- 
much as  the  ischium  contributes  in  the  pro- 
portion of  rather  more  than  two-fifths,  the  ilium 
of  about  two-fifths,  whilst  the  pubis  yields  ra- 
ther less  than  one-fifth. 

Although  the  acetabulum  is  situated  nearly 
in  the  centre  of  the  separated  os  innominatum, 
it  has  a  different  position  in  relation  to  the 
entire  pelvis.  The  union  of  the  ossa  innomi- 
nata  at  the  symphysis  pubis,  and  the  comple- 
tion of  the  pelvis  by  the  addition  of  the  sacrum 
posteriorly,  place  the  acetabular  cavities  on 
either  side  upon  the  antero-external  aspect  of 
the  pelvis,  so  that  a  line  drawn  horizontally 
from  the  one  to  the  other  would  pass  through 
the  union  of  the  anterior  with  the  two  posterior 
thirds  of  the  antero-posterior  diameter  of  the 
pelvis.  The  aspect  of  each  acetabulum  is  out- 
wards and  very  slightly  forwards  as  well  as 
downwards. 

Fach  cavity  is  surrounded  for  about  four- 
fifths  of  its  circumference  by  a  sharp  but  strong 
lip  or  margin  ( supercilium,  acetabuli ),  leaving 
opposite  the  obturator  foramen  a  notch  of 
considerable  extent  C incisura  acetabuli )  di- 
rected from  without  downwards,  forwards,  and 
inwards,  the  deepest  part  of  which  is  smooth 
and  gives  passage  to  nerves  and  vessels.  This 
notch  corresponds  to  the  junction  of  the  pubis 
and  ischium  ;  and  we  may  here  observe  that 
the  margin  of  the  acetabulum  exhibits  a  slight 


NORMAL  ANATOMY  OF  THE  HIP-JOINT. 


777 


concavity  superiorly,  corresponding  to  the 
junction  of  the  pubis  and  ilium,  and  a  similar 
one  inferiorly  and  externally,  corresponding  to 
the  junction  of  the  ilium  and  ischium.  These 
concavities  are  separated  by  intervening  con- 
vexities, and  hence  the  margin  of  the  acetabu- 
lum has  the  appearance  of  a  waving  line. 
Immediately  within  the  margin  of  the  acetabu- 
lum we  perceive  a  broad  band  of  smooth 
bone  (facies  lunatu )  covered  in  the  recent 
state  by  articular  cartilage,  about  seven-eighths 
of  an  inch  wide  at  its  lower  portion,  or  oppo- 
site the  ischium,  an  inch  and  a  quarter  to  an 
inch  and  a  half  superiorly  and  externally, 
where  it  corresponds  to  the  ilium,  and  from  a 
quarter  to  half  an  inch  internally  and  superiorly 
at  the  pubis.  This  band  terminates  at  each 
extremity  of  the  notch  already  described  in  a 
process  (cornu ),  the  superior  of  which  looks 
downwards,  outwards,  and  backwards,  whilst 
the  inferior,  more  prominent  than  the  superior, 
projects  towards  the  notch,  forming  a  kind  of 
gutter  between  its  superior  margin,  and  the 
deepest  part  of  the  notch.  Internal  to  this 
band,  there  is  a  depression,  as  it  were  a  cavity 
within  the  acetabulum,  rough  and  uneven, 
uninvested  by  cartilage  in  the  recent  state, 
being  continuous  with  the  notch  leading 
towards  the  obturator  foramen.  This  is  the 
fovea  or  sinus,  and  lodges  a  quantity  of  fatty 
cellular  tissue  formerly  termed  glands  of  Havers, 
from  their  having  been  first  described  by  that 
anatomist.  On  the  upper  and  lower  portions 
of  this  inner  cavity,  various  inequalities  and 
foramina  are  seen,  the  latter  being  for  the  pas- 
sage of  the  nutritious  vessels  of  the  bone, 
which  is  very  thin  at  this  point,  so  much  so  in- 
deed, that  if  held  up  to  the  light,  it  will  be 
found  transparent.  The  depth  of  the  acetabu- 
lum is  not  uniform  in  its  different  regions. 
This  variety  corresponds  in  a  great  measure  to 
the  breadth  of  the  smooth  band  of  bone 
(fades  lunata )  already  described.  Where 
this  is  broadest,  the  cavity  possesses  the  great- 
est depth,  and  where  it  is  entirely  absent,  the 
cavity  is  very  superficial,  as  opposite  the  notch. 

The  non-articular  circumference  of  the  lip 
of  the  acetabulum  is  rough  and  marked  by 
foramina  for  the  passage  of  nutritious  vessels, 
and  also  for  the  attachment  of  the  capsular 
ligament. 

The  head  of  the  femur,  representing  about 
three-fourths  of  a  sphere,  is  supported  and  con- 
nected to  the  shaft  of  that  bone  at  an  angle 
varying  with  age,  by  a  constricted  and  flattened 
process  termed  the  neck.  A  waving  prominent 
line  surrounds  the  head  at  its  junction  with  the 
neck,  and  may  be  regarded  as  the  boundary 
line  between  these  two  parts,  leaving  on  its 
inner  side  the  articular  surface  of  the  head  of 
the  femur,  which  is  smooth,  having  in  the 
adult  its  greater  convexity  directed  upwards 
and  inwards.  At  one  point,  however,  the  ar- 
ticular character  of  this  surface  is  interrupted 
by  a  depression,  which  is  not  covered  with  carti- 
lage in  the  recent  state.  This  depression,  situ- 
ated immediately  behind  and  below  the  point 
through  which  the  axis  of  the  head  of  the  bone 


would  pass,  gives  insertion  to  the  ligamentum 
teres. 

2.  The  cartilage. — That  portion  of  the  sur- 
face of  the  acetabulum  which  corresponds 
to  the  facies  lunata  is  alone  invested  by  articu- 
lar cartilage.  This  cartilaginous  layer  is  thick- 
est at  its  external  circumference,  becoming 
gradually  thinner  as  it  proceeds  internally. 
The  head  of  the  femur,  on  the  other  hand,  is 
nearly  entirely  incrusted  with  cartilage,  which, 
as  is  usual  on  convex  surfaces,  is  thickest 
towards  its  centre,  where  it  is  interrupted  by  the 
depression  for  the  ligamentum  teres,  and  be- 
comes progressively  thinner  towards  the  circum- 
ference. 

3.  Fibro-cartilage. — Immediately  surround- 
ing the  margin  of  the  acetabulum  is  a  fibro- 
cartilaginous ring  about  three  lines  broad,  tri- 
angular in  shape,  having  its  base  attached  to 
the  brim  of  the  cavity,  whilst  its  apex  is  free. 
This  is  the  so-called  cotyloid  ligament  (ligamen- 
tum cotyloideum,  fibro-cartilagineum,  labium 
cartilugineum  acetabuli.)  It  clearly  belongs  to 
the  fibro-cartilages  of  circumference,  and  is 
the  counterpart  of  the  glenoid  ligament  in  the 
shoulder-joint  (see  Fibro-cartilage),  and  as 
it  completely  removes  the  irregular  character 
of  the  margin  of  the  acetabulum,  it  will  be 
found  to  be  deepest  where  it  corresponds  to  the 
concavities  of  the  acetabular  border.  Its  free 
border  is  sharp,  and  directed  inwards,  i.  e., 
towards  the  centre  of  the  joint,  narrowing  the 
orifice  of  the  acetabulum,  at  the  same  time  that 
it  increases  the  depth  of  that  cavity.  Its  fixed 
margin  constitutes  its  base,  and  is  connected  to 
the  brim  of  the  acetabulum ;  its  external  sur- 
face covered  by  synovial  membrane  corres- 
ponds to  the  capsular  ligament,  whilst  its  inter- 
nal, also  covered  by  synovial  membrane,  em- 
braces the  head  of  the  femur.  Having  arrived 
at  the  notch,  it  is  continued  over  each  cornu  of 
the  facies  lunata,  retaining  somewhat  of  its 
form,  but  much  diminished  in  dimensions,  and 
having  assumed  much  more  the  appearance  of 
pure  cartilage  than  of  fibro-cartilage.  It  ceases 
at  the  point  at  which  the  concave  margin  of  the 
facies  lunata  becomes  blended  with  the  con- 
vexity of  each  cornu.  It  is  not  stretched 
across  the  notch  as  some  anatomists  erroneously 
describe  it.  The  whole  extent  of  this  fibro- 
cartilage,  then,  corresponds  exactly  to  the  con- 
vex margin  of  the  facies  lunata. 

4.  Ligaments. — The  notch  of  the  acetabu- 
lum is  converted  into  a  foramen,  strengthened 
and  in  a  great  degree  closed  by  ligamentous 
fibres  arranged  in  two  layers,  and  extended 
from  the  superior  to  the  inferior  cornu.  The 
whole  forms  the  ligamentum  transversale  aceta- 
buli of  Winslow.  Of  these  the  external  and 
deepest  arises  from  the  superior,  and  is  inserted 
into  the  inferior  cornu  of  the  acetabulum.  The 
external  surface  of  this  layer,  directed  obliquely 
backwards  towards  the  cavity  of  the  acetabulum, 
corresponds  and  gives  attachment  to  the  liga- 
mentum teres.  Its  internal  surface  is  applied 
to  the  external  layer ;  its  external  margin  is 
attached  to  the  capsular  ligament,  and  its  inter- 
nal superiorly  to  the  pubis,  but  inferiorly  it  is 


778 


NORMAL  ANATOMY  OF  THE  HIP-JOINT. 


free,  and  bounds  a  foramen  for  the  passage  of 
vessels.  The  internal  layer  of  the  transverse 
ligament  is  attached  below  to  the  inferior  cornu, 
and  above  to  the  superior,  where  it  appears  to 
blend  with  the  cotyloid  ligament.  By  its  exter- 
nal surface  it  is  in  apposition  with  the  external 
layer  of  the  transverse  ligament,  and  its  inter- 
nal surface  is  directed  towards  the  obturator 
ligament  and  external  obturator  muscle.  Some 
fibres  pass  from  its  upper  margin  to  the  obtu- 
rator ligament ;  but  in  greatest  part  this  mar- 
gin contributes  to  form  the  foramen  already 
described  for  the  passage  of  vessels.  Its  infe- 
rior margin  affords  attachment  to  the  capsular 
ligament. 

Round  ligament.  (  Ligamenfmn  teres  capitis 
fomoris  seu  ligamentum  inter-articular e.) — 
This  ligament,  which  was  first  described  by 
Vesalius,  has  very  improperly  received  the 
epithet  round,  inasmuch  as  in  point  of  fact  it  is  a 
triangular  fasciculus,  about  an  inch  and  a  half  in 
length,  having  its  base  attached  to  the  aceta- 
bulum and  its  apex  to  the  depression  on  the 
head  of  the  femur.  It  is  most  advantageously 
placed  for  escaping  injury  in  the  various 
motions  of  the  joint,  as,  independently  of  its 
corresponding  to  the  soft  cushion  contained  in 
the  excavation  of  the  acetabulum,  its  direction 
and  attachments  completely  remove  it  from  all 
danger  on  this  score.  It  is  attached  by  the 
superior  portion  of  its  base  to  the  upper  cornu 
of  the  notch,  and  to  the  external  layer  of  the 
tranverse  ligament;  and  by  the  inferior  and 
larger  portion  of  its  base  to  the  lower  cornu,  as 
well  as  to  the  external  layer  of  the  tranverse 
ligament;  from  these  points  of  attachment  its 
direction  in  the  quiescent  state  of  the  limb, 
i.  e.  the  femur  being  placed  vertically  under 
the  pelvis,  is  upwards,  outwards,  and  back- 
wards, to  its  insertion  into  the  head  of  the 
femur.* 

When  the  joint  is  cut  into  in  the  recent  state, 
there  are  processes  seen  extending  from  this 
ligament  towards  the  circumference  of  the  exca- 
vation ;  these  should  not  be  mistaken  for  por- 
tions or  attachments  of  the  ligamentum  teres ; 
they  are  folds  of  the  synovial  membrane  pro- 
ceeding from  that  ligament  over  the  surface  of 
the  acetabulum.  Situated  in  the  rough  exca- 
vation of  the  acetabulum,  and  forming  a  cushion 
for  the  ligamentum  teres  in  the  several  motions 
and  positions  of  the  head  of  the  femur,  is  the 
soft  pulpy  mass  of  fatty  cellular  tissue,  covered 
by  synovial  membrane,  already  alluded  to  as  the 
glands  of  Havers,  first  described  and  figured  by 
that  anatomist  in  his  Osteologia  Nova. 

Capsular  ligament. — The  hip-joint  is  com- 
pleted by  a  strong  fibrous  investment,  termed 
capsular  ligament  ( capsula  fibrosa  ossis  fe- 
moris).  This  is  by  far  the  strongest  and 
largest  capsular  ligament  in  the  body.  How- 
ever it  is  by  no  means  uniform  in  its  strength 
and  thickness,  these  being  greatly  increased  by 

*  [Weber  states  that,  in  the  erect  posture,  the 
direction  of  the  ligamentum  teres  is  vertical.  See 
Mcchanik  der  Menschlichen  Gehwcrkzeuge,  p.  143, 
and  pi.  ii.  fig.  1. — Ed.] 


super-imposed  fibres  in  those  situations  upon 
which  a  considerable  force  is  exercised  in 
certain  motions  of  the  joint.  It  not  only  em- 
braces the  articulation,  but  also  includes  the 
neck  of  the  femur,  to  the  base  of  which  it 
extends  from  the  os  innominatum.  Its  fibres 
are  variously  directed  from  the  os  innomi- 
natum, to  which  they  are  firmly  attached 
from  the  margin  of  the  acetabulum  to  a 
considerable  distance  on  the  dorsum  of  that 
bone.  Superiorly  and  externally  they  may  be 
traced  as  far  as  the  inferior  anterior  spinous 
process  of  the  ilium  in  front,  whilst  posteriorly 
the  great  sciatic  notch  marks  their  boundary, 
and  an  arched  line  drawn  from  the  inferior 
anterior  spine  of  the  ilium  to  the  spine  of  the 
ischium  denotes  with  tolerable  exactness  their 
attachment  in  this  direction.  Inferiorly  and 
externally  they  are  attached  to  that  portion  of 
the  ischium  situated  between  the  cotyloid  cavity 
and  the  external  lip  of  the  tuber  ischii,  and  to 
this  latter  itself  by  very  strong  dense  fibres. 
Superiorly  and  internally  they  arise  from  that 
portion  of  the  ilium  situated  between  its  an- 
terior inferior  spine  and  the  ilio-pectineal 
eminence,  and  from  the  pubis  as  far  as  the 
superior  cornu  of  the  acetabulum.  Inferiorly 
and  internally  the  capsule  is  attached  to  the 
transverse  ligament  of  the  cotyloid  cavity. 

By  this  description  we  perceive  that  the  cap- 
sular ligament  is  firmly  attached  to  the  os  inno- 
minatum ;  that  with  the  exception  of  the  portion 
arising  from  the  transverse  ligament  its  origins  at 
all  points  are  from  an  inch  to  nearly  two  inches 
in  extent.  Passing  in  various  directions,  ac- 
cording to  their  several  situations,  the  fibres 
run  to  be  inserted  into  the  base  of  the  neck 
of  the  femur,  anteriorly  into  the  anterior  inter- 
trochanteric line,  superiorly  and  externally  into 
the  surface  of  the  bone  close  to  the  digital 
fossa  at  the  root  of  the  great  trochanter,  inferi- 
orly and  internally  to  the  line  leading  from  the 
lesser  trochanter  to  the  anterior  inter-trochan- 
teric  line,  and  posteriorly  it  is  partly  reflected 
upwards,  so  as  to  become  continuous  with  the 
periosteum  of  the  posterior  part  of  the  neck  of 
the  bone ;  this  reflection  taking  place  along  the 
posterior  inter-trochanteric  line,  and  partly  in- 
serted into  that  line,  especially  at  its  internal  and 
external  extremities.  The  reflected  portion  is 
derived  from  the  deep  fibres  of  the  capsule, 
which  in  passing  upwards  to  be  inserted  into 
the  bone  at  the  circumference  of  the  head,  con- . 
tribute  to  form  those  bands  of  fibrous  mem- 
brane, which  are  manifest  on  the  posterior  aspect 
of  the  neck  of  the  femur  on  opening  the  cap- 
sule, being  covered  only  by  synovial  membrane. 
These  bands  are  sometimes  of  considerable 
strength,  and  they  are  well  described  and 
figured  by  VVeitbrecht,*  by  whom  they  were 
designated  retinacula. 

We  have  already  observed  that  the  capsular 
ligament  is  not  uniform  in  thickness  at  all 
points.  At  the  outer  part  of  its  anterior  sur- 
face its  thickness  is  very  considerable,  being 
strengthened  and  increased  by  a  band  of  fibres 

*  Syndcsmologia,  Pctrop.  1742. 


NORMAL  ANATOMY  OF  THE  HIP-JOINT. 


779 


of  some  magnitude  (accessory  ligament),  arising 
from  the  inferior  anterior  spine  of  the  ilium 
and  the  space  beneath,  from  which  they  descend, 
diverging  to  be  inserted  into  the  anterior  inter- 
trochanteric line  ;  these  fibres  are  so  much  de- 
veloped in  some  instances  as  almost  to  re- 
semble a  distinct  ligament.  At  this  point  the 
capsule  is  nearly  half  an  inch  thick.  Externally 
its  thickness  is  considerable,  though  somewhat 
less  than  at  the  point  last  described.  From 
the  pubis  a  smaller  and  thinner  band  of  acces- 
sory fibres  may  be  traced  towards  the  lesser 
trochanter,  strengthening  the  capsule  in  this 
situation  ;  between  the  two  accessory  bands  in 
the  centre  of  the  anterior  surface,  the  capsule  is 
extremely  thin,  and  sometimes  wholly  destitute 
of  fibrous  tissue,  being  altogether  composed  of 
synovial  membrane,  and  a  little  cellular  tissue, 
by  which  it  is  separated  from  the  bursa  that 
lies  under  the  tendon  of  the  psoas  muscle : 
this  bursa,  moreover,  sometimes  communicates 
with  the  cavity  of  the  joint  through  an  opening 
in  this  situation. 

The  internal  surface  of  the  capsule  invested 
by  its  synovial  membrane  corresponds  to  the 
cotyloid  ligament,  to  the  neck  and  a  portion  of 
the  head  of  the  femur.  The  external  is  covered 
anteriorly  by  the  rectus  femoris,  psoas,  and 
iliacus  muscles,  internally  by  the  obturator 
externus  and  pectineus ;  posteriorly  it  lies  upon 
the  quadratus  femoris,  gemelli,  pyriformis, 
and  obturator  internus,  and  superiorly  the 
gluteus  minimus  adheres  very  closely  to  it. 

The  capsule  of  the  hip-joint,  although 
stronger,  is  not  so  long  or  so  loose  as  that  of 
the  scapulo-humeral  articulation,  neither  is  it 
pierced  by  any  tendon. 

Synovial  membrane. — To  facilitate  descrip- 
tion, let  us  commence  at  the  greatest  circum- 
ference of  the  head  of  the  femur.  From  this 
point  the  synovial  membrane  passes  outwards 
over  the  neck  of  the  bone  as  far  as  the  attach- 
ment of  the  capsular  ligament ;  from  the  bone 
it  is  reflected  on  to  the  deep  surface  of  this 
ligament,  along  which  it  passes  to  the  line  of 
its  attachment  to  the  os  innominatum  and 
transverse  ligament :  along  that  line  it  is  re- 
flected again  on  to  the  margin  of  the  acetabu- 
lum over  the  cotyloid  ligament  into  the  cavity, 
which  it  completely  lines,  and  from  which  it  is 
carried  by  the  round  ligament,  which  it  invests, 
to  the  head  of  the  femur. 

Arteries. — The  hip-joint  is  supplied  with 
blood  by  branches  from  the  obturator  artery, 
derived  from  the  internal  iliac  or  from  the  in- 
ternal circumflex  branch  of  the  femoral.  These 
are  distributed,  some  in  the  fat  and  cellular 
tissue,  filling  the  excavation  at  the  bottom  of 
the  acetabulum,  whilst  others  ramify  on  the 
ligamentum  teres,  and  are  conducted  by  it  to 
the  head  of  the  femur.  It  not  unfrequently 
occurs  that  the  joint  receives  blood  from  both 
these  sources. 

Nerves. — These  are  derived  from  the  obtu- 
rator, which  uniting  with  the  deep  division  of 
the  anterior  crural  cause  the  pain  to  be  referred 
to  the  knee  in  some  diseases  of  the  hip-joint. 

Motions. — The  motions  of  this  joint  are 
mostly  performed  by  the  femur  upon  the  os 


innominatum,  and  consist  of  flexion,  exten- 
sion, abduction,  adduction,  circumduction,  and 
rotation. 

In  slight  flexion  the  head  of  the  femur 
revolves  upon  its  axis  in  the  cotyloid  cavity ; 
the  anterior  portion  of  the  capsular  liga- 
ment being  relaxed,  whilst  the  posterior  is 
rendered  proportionally  tense.  If  this  motion 
be  augmented  to  any  considerable  extent,  the 
capsular  ligament  is  relaxed  to  a  greater  degree 
anteriorly,  whilst  posteriorly,  in  consequence  of 
the  distance  between  its  two  points  of  attach- 
ment being  increased,  it  is  very  tense,  and  ren- 
dered convex  by  being  stretched  over  the  head 
of  the  femur,  which  is  now  very  prominent  in 
this  situation,  resulting  from  the  altered  re- 
lations between  it  and  the  acetabulum.  The 
anterior  part  of  the  head  of  the  femur  is  placed 
against  the  deepest  portion  of  the  acetabulum, 
whilst  its  broad  articulating  surface  situate 
above  the  depression  for  the  round  ligament  is 
directed  backwards,  where  the  acetabulum  is 
too  shallow  to  receive  it  completely  ;  it  there- 
fore forms  a  projection  in  this  situation,  a  pro- 
jection which,  in  my  opinion,  ought  rather  to 
be  attributed  in  this  instance  to  the  natural 
formation  of  the  parts  than  to  any  displacement 
of  the  head  of  the  bone. 

When  excessive  flexion  is  combined  with 
adduction,  the  head  of  the  femur  glides  from 
before  backwards,  and  from  within  outwards  in 
the  acetabulum ;  its  anterior  portion  is  con- 
cealed in  tins  cavity,  whilst  its  posterior 
emerging  lies  against  the  capsular  ligament, 
considerably  increasing  its  tension.  To  pro- 
duce these  motions  muscles  of  great  power  are 
employed  ;  in  some  these  agents  are  not  con- 
fined merely  to  one  joint,  but  have  two  oppo- 
site functions  to  perform,  being  flexors  of  one 
joint  at  the  same  time  that  they  extend  another. 

In  abduction,  when  the  lower  extremity  of 
the  femur  is  separated  from  the  median  line, 
its  head  is  naturally  directed  downwards, 
its  inferior  portion  being  forced  against  the 
capsular  ligament ;  therefore  when  the  motion 
is  carried  to  any  great  extent  the  ligament  is 
liable  to  rupture,  and  allow  the  head  of  the 
femur  to  escape  over  the  internal  lip  of  the 
acetabulum  into  the  obturator  foramen. 

In  adduction  the  same  occurs  as  in  abduc- 
tion, but  in  an  inverse  direction,  with  this  ex- 
ception, that  as  the  motion  cannot  be  carried 
so  far,  and  as  in  this  case  the  head  of  the 
femur  is  opposed  to  the  deepest  portion  of 
the  acetabulum,  dislocation  cannot  occur. 
Simple  adduction,  unaccompanied  by  any 
flexion  of  the  joint,  is  very  limited.  Let 
any  one,  while  standing  in  the  erect  pos- 
ture, approximate  his  knees,  it  will  be  found 
that  the  utmost  he  can  do  is  to  bring  them  very 
near  to  each  other,  but  that  he  cannot  press 
them  against  each  other ;  if,  however,  the  hip- 
joints  have  been  previously  very  slightly  flexed, 
then  the  knees  may  be  easily  pressed  against 
each  other,  and  the  adduction  may  be  carried  to 
a  much  greater  extent,  so  as  to  cross  the  legs. 
It  is  limited  by  the  ligamentum  teres  and  the 
external  and  anterior  part  of  the  capsular  liga- 
ment. 


780 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


Circumduction  combining  the  four  preceding 
is  a  compound  movement,  in  which  the  inferior 
extremity  describes  a  cone,  the  apex  of  which 
is  at  the  joint ;  the  head  of  the  femur  in  the 
course  of  this  motion  successively  assumes  the 
several  situations  already  described. 

In  rotation  outwards  the  head  of  the  femur 
is  directed  forwards  and  inwards,  the  anterior 
surface  of  the  neck  looks  outwards,  the  pos- 
terior inwards  resting  on  the  brim  of  the  ace- 
tabulum ;  the  capsular  ligament  is  put  upon 
the  stretch  on  its  inner  side.  Any  sudden  jerk 
or  violence  when  in  this  position  is  liable  to 
produce  dislocation  upwards  upon  the  pubis. 

In  rotation  inwards  the  bone  assumes  the 
contrary  direction,  and  the  capsular  ligament 
and  ligamentum  teres  are  equally  put  upon  the 
stretch.  In  this  case  dislocation  may  occur 
either  upon  the  dorsum  of  the  ilium  or  into  the 
sciatic  notch.  For  this  motion  we  have  but  few 
muscles,  this  position  being  produced  merely 
by  the  tensor  vaginae  femoris  and  anterior  fibres 
of  the  gluteus  medius  muscles.  The  disparity 
between  the  number  of  muscles  influencing  the 
motions  of  rotation  outwards  and  inwards  is 
very  striking,  but  this  may  be  attributed  to  the 
direction  of  the  acetabulum  from  within  out- 
wards and  forwards  naturally  tending  to  pro- 
duce rotation  inwards.  Consequently  before 
the  opposite  motion  can  be  effected  there  is 
this  inequality  to  be  overcome,  and  hence  the 
disparity  between  the  muscles. 

( H.  Hancock.) 

HIP -JOINT,  ABNORMAL  CONDI- 
TIONS OF  THE— In  this  article  we  shall 
adopt  an  arrangement  similar  to  that  which  we 
have  followed  in  our  former  observations  on  the 
abnormal  conditions  of  particular  joints,  and 
consider  these  states  under  the  heads  of,  1. 
congenital  malformations;  2.  the  effects  of 
disease,  and,  3.  the  results  of  accident. 

Section  I.  Congenital  malformation  of  the 
hip-joint. — The  peculiar  affection  termed  by  the 
continental  surgeons  congenital  or  "original  lux- 
ation "  of  the  hip-joint,  has  not  in  our  islands  at- 
tracted the  notice  that  it  seems  to  us  to  merit. 
When  we  reflect  upon  the  very  valuable  addi- 
tions which  have  been  made  to  our  knowledge  of 
the  pathology  of  the  articulations  by  British 
writers,  and  observe  their  silence  upon  this  ab- 
normal state  of  the  hip-joint,  we  might  be  led 
to  infer  that  this  malformation  had  no  existence 
in  these  islands;  this,  however,  unfortunately  is 
not  true. 

In  the  very  valuable  museums  in  London  we 
can  easily  recognise  many  unquestionable  spe- 
cimens of  this  congenital  malformation  of  the 
bones  of  the  hip-joint.  In  Dublin  we  know 
some  living  examples  of  it,  and  our  museums 
contain  preparations  shewing  some  of  its  va- 
rieties and  most  of  its  usual  anatomical  charac- 
ters. 

At  the  meeting  of  the  British  Association  in 
Dublin  in  the  year  1835,  Dr.  Hutton  made 
some  interesting  observations  on  this  affection 
to  the  section  of  medical  science,  and  gave  an 
account  of  a  well-marked  example  of  it  affect- 
ing one   hip-joint.    On    that  occasion  Dr. 


Handyside  observed  that  he  had  met  with  a 
case  of  congenital  luxation  of  both  hip-joints, 
in  a  subject  which  had  been  brought  into  his 
anatomical  rooms  at  Edinburgh ;  and  he  added 
that  the  appearances  of  the  joints  corresponded 
very  closely  with  those  noticed  by  Dr.  Hutton. 
The  Professor  of  Anatomy  and  Surgery  to  the 
University  of  Dublin,  Dr.  Harrison,  laid  before 
the  Surgical  Society  last  winter  the  results  of 
two  accurate  post-mortem  examinations  which 
he  had  made  of  this  malformation  of  the  hip- 
joint.  The  history  of  these  cases,  as  far  as  Dr. 
Harrison  could  make  it  out,  shewed  that  the 
subjects  of  them  had  during  life  presented  the 
ordinary  signs  of  the  infirmity  in  question. 
In  one  of  them,  one  hip-joint  only  was  af- 
fected ;  in  the  second,  not  only  was  the  arrest 
of  development  such  as  to  leave  the  acetabu- 
lum a  plane  surface  by  depriving  it  of  border 
of  any  kind,  but  the  ligamentum  teres,  the 
head  and  greater  part  of  the  cervix  femoris 
were  also  deficient  on  both  sides,  so  that  the 
femora  at  their  upper  extremity  presented  a 
rude  resemblance  to  the  ossa  humeri.  In  this 
case  (jig.  307)  the  capsular  ligament  was  of  an 
extraordinary  length,  and  permitted  the  rudi- 
ment of  a  head  and  neck,  with  the  trochanter 
major,  to  ascend  and  descend  on  each  side  on 
the  dorsum  ilh,  and  to  pass  backwards  on  the 
ischium  to  the  very  edge  of  the  ischiatic  notch, 
in  the  different  movements  of  the  patient. 

The  case  of  congenital  malformation  of  the 
hip-joint  has  not  escaped  the  notice  of  conti- 
nental surgeons,*  although  perhaps  the  nature  of 
the  affection  had  not  fully  attracted  the  attention 
of  the  profession  until  Dupuytrenf  gave  the 
results  of  his  observations  of  twenty-six  cases  of 
this  malformation  which  were  presented  to  him 
in  the  course  of  his  public  and  private  practice. 
He  seems  to  have  met  with  the  affection  more 
frequently  in  the  female  than  in  the  male,  in 
the  vast  proportion  of  twenty-two  females  to 
four  males,  and  from  his  description  it  would 
appear  that  he  has  usually  found,  in  the  same 
individual,  both  hip-joints  affected.  In  the 
cases  we  have  witnessed,  we  have  not  observed 
this  very  great  preponderance  of  female  over 
male  cases ;  and  although  we  have  noticed  the 
defect  to  be  double  in  the  same  individual,  we 
have  more  frequently  observed  but  one  joint 
engaged.  This  is  of  importance  to  be  recol- 
lected, as  mistakes  in  our  diagnosis  are  more 
likely  to  occur  when  only  one  joint  is  affected, 
than  in  those  cases  in  which  the  defect  is 
double  in  the  same  individual. 

The  characters,  says  Dupuytren,  of  this 
"  original  luxation"  are  nearly  similar  to  all 
those  we  notice  belonging  to  the  ordinary  luxa- 
tion upwards  and  backwards  on  the  dorsum 
of  the  ilium  :  the  limbs  are  shortened  and  inver- 
ted ;  the  superior  extremities  of  the  femora  are 
carried  upwards,  backwards,  and  outwards,  into 
the  external  iliac  fossa,  where  a  considerable 
prominence  can  be  seen,  caused  by  the  unusual 
elevation  of  the  great  trochanter;  the  thighs, 
unusually  slender,  are  obliquely  directed  down- 

*  Palletta,  Lafond,  Callard,  Bcllomeir. 
t  Repertoire  d' Anatomic,  Lemons  Orales. 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


781 


wards,  forwards,  and  inwards,  and  this  obliquity 
is  greater  in  proportion  as  the  pelvis  is  broader ; 
hence  the  deformity  in  the  female  increases 
about  the  age  of  puberty:  there  is,  in  conse- 
quence of  this  breadth  of  the  pelvis,  a  tendency 
of  the  limbs  to  cross  each  other  inferiorly,  and 
the  movements  they  are  found  to  enjoy  are 
very  limited,  particularly  those  of  abduction 
and  rotation;  hence  the  individual  finds  great 
difficulty  in  performing  the  different  functions 
belonging  naturally  to  the  inferior  limbs. 
When  we  examine  a  person  with  this  double 
defect  standing,  we  are  struck  at  once  with  the 
apparent  want  of  proportion  between  the  superior 
and  inferior  parts  of  the  body,  with  the  imper- 
fection of  the  lower  limbs,  and  with  the  peculiar 
attitude  of  the  patient.  The  trunk  is  fully  deve- 
loped, says  Dupuytren,  whilst  the  inferior  limbs, 
short  and  slender,  seem  as  if  they  were  suited 
only  to  au  individual  of  smaller  stature.  When 
we  view  the  patient  laterally,  we  observe  that  the 
chest  and  superior  part  of  the  body  are  carried 
very  much  backwards,  while  the  anterior  part 
of  the  abdomen  is  thrown  very  prominently 
forwards,  and  at  the  same  time  we  notice  there 
is  a  corresponding  hollowing  posteriorly  in  the 
region  of  the  loins,  and  that  the  nates  jut  out 
backwards  most  conspicuously.  A  very  cha- 
racteristic circumstance  relative  to  the  standing 
position  of  these  malformed  individuals  is,  that 
they  rest  on  the  ground  only  by  the  anterior 
part  of  their  feet;  most  of  the  peculiar  cir- 
cumstances relating  to  the  attitude  of  these 
persons  follow  as  the  necessary  consequence  of 
their  hip-joints  (or  in  other  words  the  centre 
of  motion  of  the  lower  extremities)  being  placed 
behind  their  ordinary  situation  with  respect  to 
the  pelvis. 

If  a  patient  so  unhappily  constituted  wish  to 
walk,  we  see  him  incline  the  superior  part  of 
his  body  towards  the  limb  which  is  now  in- 
tended to  support  the  weight  of  the  body  ;  he 
as  it  were  balances  himself  on  the  anterior  part 
of  the  foot  of  this  side  ;  he  next  raises  from  the 
ground  the  opposite  foot,  and  transfers  labori- 
ously his  weight  from  one  side  to  the  other — 
indeed  each  time  this  motion  takes  place,  the 
head  of  the  femur  which  receives  the  weight  of 
the  body,  ascends  upon  the  external  iliac  fossa, 
and  is  sustained  by  its  ligaments  and  muscles ; 
the  pelvis  is  at  the  same  time  depressed,  and 
all  the  signs  of  displacement  become  more  ob- 
vious on  this  side,  while  they  diminish  sensibly 
on  the  other ;  in  a  word,  progression  thus  be- 
comes an  awkward  and  waddling  movement. 

It  may  appear  singular  that  running  and 
leaping  should  be  executed  by  these  patients 
with  more  facility  than  walking,  yet  such  is 
the  fact;  for  in  those  exertions  the  energy  of 
muscular  contraction,  and  the  rapidity  with 
which  the  weight  of  the  body  is  transferred  from 
one  limb  to  the  other,  are  such,  that  the  want 
of  a  true  acetabulum  is  not  so  much  felt 
as  in  walking.  Any  of  these  exercises,  how- 
ever, very  soon  induce  fatigue,  which  we  can 
readily  account  for  when  we  recollect  the 
friction  which  the  head  of  the  femur  must  un- 
dergo against  the  side  of  the  pelvis,  and  the 
great  efforts  which  the  muscles  have  to -sustain 


in  supporting  the  weight  of  tRe  body,  during  the 
balancing  or  waddling  motion  described.  When 
persons  afflicted  with  this  malformation  lie 
down  horizontally  on  their  back,  the  signs  of 
their  infirmity  become  so  slight  as  to  be 
scarcely  perceptible,  because  in  this  situation 
of  complete  repose  the  muscles  do  not  draw 
upwards  the  lower  limbs,  nor  does  the  weight 
of  the  body  depress  the  pelvis.  Dupuytren 
found  that  in  this  situation  of  the  body  he 
could  elongate  or  shorten  the  affected  limbs 
of  the  patient;  to  elongate  them,  he  says,  it 
was  merely  necessary  to  pull  slightly  down- 
wards at  the  knee  or  ankle,  and  to  shorten 
them,  to  push  them  upwards;  the  head  of  the 
femur  will  undergo  in  such  experiments  a  dis- 
placement of  one,  two,  or  even  three  inches 
(Dupuytren),  and  all  these  displacements  will 
be  affected  without  causing  any  pain  and  with 
the  greatest  ease,  convincing  us  that  no  proper 
cavity  exists  fit  to  receive  and  retain  the  head 
of  the  femur. 

It  is  of  importance  that  this  congenital  mal- 
formation of  the  hip-joint  should  be  well  under- 
stood, not  only  that  dangerous  errors  in  diagnosis 
may  be  avoided,  but  that  this  defect,  when  it 
really  exists,  may  be  recognized  early,  so  that 
timely  and  proper  treatment  may  be  resorted  to. 
It  presents  to  the  superficial  observer  many  of 
the  signs  which  belong  to  a  disease  of  the  hip- 
joint  ;  and  of  the  cases  seen  by  Dupuytren,  few, 
he  says,  had  been  recognized  by  the  surgeons 
previously  consulted  :  almost  all  these  unfor- 
tunate patients  had  been  subjected  to  painful  and 
worse  than  useless  treatment.  Many  individuals 
afflicted  with  original  luxation  of  the  hip-joint 
have  been,  in  consequence  of  the  errors  or  igno- 
rance of  their  medical  attendants,  condemned 
to  keep  their  beds  during  many  years.  "  I  have 
seen  others,"  says  he,  "  whom  they  had  forced  to 
submit  to  numberless  applications  of  leeches, 
blisters,  issues,  and  moxas ;  among  others  I 
remember  the  case  of  a  young  girl,  who  suffered 
the  application  of  twenty-one  moxas  around  the 
hip,  without  this  barbarous  treatment  having 
effected  any  favourable  change  in  the  situation 
of  this  unfortunate  patient." 

We  can  easily  distinguish  this  original 
luxation  from  disease  of  the  hip-joint,  as  there 
is  no  pain  felt  by  the  patient  either  in  the  hip 
or  knee  ;  there  is  neither  heat,  swelling,  nor 
abscess,  no  evidence  of  inflammation  chronic  or 
acute,  nor  is  there  any  cicatrix  ;  consequently 
nothing  exists  which  can  induce  us  to  believe 
that  heretofore  there  ever  existed  any  abscess  or 
fistula,  consequences  so  very  usual  in  cases  of 
disease  of  the  hip-joint,  when  this  disease  has 
arrived  at  the  stage  of  luxation. 

Dupuytren's  description  of  this  condition  of 
the  hip-joint  seems  to  apply  altogether  to  the 
case  in  which  both  joints  are  engaged ;  when 
one  articulation  only  is  affected,  so  far  as 
it  is  concerned,  the  features  of  the  congenital 
defect  are  just  as  well  marked  as  those  above 
alluded  to.  The  usual  signs  of  the  dislocation 
upwards  and  backwards  on  the  dorsum  ilii,  and 
the  same  range  of  ascent  and  descent  of  the  head 
of  the  femur  on  the  ilium  and  towards  the  ischi- 
atic  notch,  is  noticed  as  in  the  former  case  ;  as-, 


782 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


however,  the  weight  of  the  body  is  almost 
entirely  thrown  on  the  unaffected  limb,  the 
latter  becomes  much  larger  and  stronger  than 
usual,  while  the  malformed  limb  falls  into  a 
state  of  more  or  less  of  atrophy  from  want  of 
use;  its  circulation  in  general  seems  more 
languid,  and  its  nervous  energies  and  tempera- 
ture are  less  than  those  of  the  well-formed  ex- 
tremity ;  add  to  this,  as  we  have  already  noticed 
(what  might  be  expected,)  that  in  consequence 
of  the  centre  of  gravity  being  so  uniformly 
thrown  on  the  sound  limb,  a  lateral  curvature 
of  the  spine  takes  place,  and  a  great  mobility 
of  the  sacro-lumbar  articulation  exists. 

Anatomical  characters  of  this  affection. — 
Opportunities  for  ascertaining  the  anatomy  of 
this  congenital  defect,  whether  both  hip-joints 
be  implicated  or  one  only  affected,  are  very 
rare.  Although  Dupuytren  has  seen  so  many 
patients  afflicted  with  this  malformation,  he  has 
had  very  few  opportunities,  he  says,  of  study- 
ing its  anatomy,  because  the  affection  is  not  a 
disease,  but  an  infirmity  which  has  no  tendency 
to  shorten  life.  With  respect  to  the  muscles  he 
has  remarked,  that  some  of  them  around  the 
joint  are  found  to  be  well  developed,  while 
others  are  in  a  state  of  atrophy :  the  first  are 
those  which  have  still  preserved  their  functions, 
the  second  are  those  whose  action  has  been 
restrained  by  changes  induced  in  the  position 
and  form  of  the  parts  :  some  of  these  latter,  he 
says,  are  reduced  to  a  sort  of  yellow  fibrous 
tissue,  in  which  we  can  scarcely  discover  mus- 
cular fibre. 

The  cotyloid  cavity  of  the  os  ilii  in  some 
cases  scarcely  can  be  said  to  exist,  so  irregular 
are  the  traces  of  it;  sometimes  an  irregular 
bony  eminence  occupies  its  place,  having  no 
cartilaginous  covering,  no  rudiment  of  cotyloid 
ligament ;  it  is  merely  surrounded  by  resistant 
cellular  tissue,  and  covered  by  muscles  which 
pass  by  it  to  be  inserted  into  the  little  tro- 
chanter. Sometimes,  says  Dupuytren,  I  have 
found  the  ligamentum  teres  of  the  articulation 
much  elongated,  flattened  superiorly,  and  worn 
as  it  were  in  certain  points  by  the  pressure  and 
friction  of  the  head  of  the  femur ;  the  latter  is 
lodged  in  a  cavity  analogous  enough  to  that 
which  we  find  formed  in  cases  of  luxation  up- 
wards and  outwards,  which  have  been  left  for  a 
long  time  unreduced.  This  cavity  (if  such  it 
can  be  called)  is  situated  in  the  external  iliac 
fossa,  above  and  behind  the  usual  situation  of 
the  cotyloid  cavity,  at  a  height  proportioned 
to  the  shortening  of  the  limb,  or  degree  of  ascent 
of  the  head  of  the  femur.  The  superior  portion 
of  the  femur  preserves  in  all  its  parts,  its  form, 
its  dimensions,  and  its  natural  relations,  only 
the  internal  side,  and  the  anterior  part  of  the 
head  of  this  bone  has  sometimes  lost  its 
rounded  form,  a  circumstance  which  would  ap- 
pear to  result  from  the  friction  which  it  has  been 
subjected  to  by  its  frequent  contact  with  parts 
which  have  not  been  organized  to  receive  it. 

The  writer's  observation  does  not  entirely 
correspond  with  this  account  of  the  superior 
portion  of  the  femur  preserving  its  form  and 
natural  relations  with  the  rest  of  the  bone.  He 
has  usually  noticed  that  the  head  of  the  femur 


has  lost  its  spheroidal  shape,  and  presents 
somewhat  of  a  conical  appearance,  as  Dupuy- 
tren well  describes  ;  but  two  other  circumstances 
he  has  observed  in  almost  all  the  cases  he  has 
examined,  whether  in  the  recent  dissections  he 
has  himself  witnessed,  or  in  the  macerated 
bones  he  has  seen  in  Dublin  or  elsewhere  : — 
1st,  that  the  neck  of  the  femur,  instead  of 
having  its  axis  directed,  as  it  naturally  is,  from 
behind  forwards,  upwards,  and  inwards,  has  in 
this  malformation  lost  its  usual  relation  with 
the  shaft  of  the  thigh-bone,  and  the  axis  is 
directed  upwards,  and  almost  directly  forwards. 
This  alteration  in  the  direction  of  the  axis  of 
the  neck  of  the  thigh-bone  did  not  escape  the 
observation  of  Dr.  Hutton,  in  his  remarks  on 
his  case  already  alluded  to ;  he  expressed  his 
idea  of  the  altered  direction  of  the  axis  by  say- 
ing that  the  axis  of  the  neck  in  this  case  fell 
directly  on  the  anterior  part  of  the  upper  ex- 
tremity of  the  shaft :  "  the  relative  position  of  the 
neck  and  shaft  appeared  as  it  might  be  supposed 
to  do  if,  the  lower  portion  of  the  femur  being- 
fixed,  the  upper  portion  were  twisted  forwards, 
the  head  moving  through  one  fourth  of  a  circle." 
2dly.  The  other  circumstance  which  the  writer 
has  noticed  must  be  viewed  in  connec- 
tion with  this  altered  direction  of  the  usual 
axis  of  the  neck  of  the  femur  just  alluded  to  ; 
it  is  that  in  all  the  cases  he  has  as  yet  seen  of 
this  original  luxation  of  the  femur,  the  head  of 
the  thigh-bone,  instead  of  being  directed  back- 
wards, as  it  is  in  the  ordinary  luxation  on  the 
dorsum  ilii,  on  the  contrary  has  been  directed 
forwards,  and  has  been  placed  beside  the 
anterior  inferior  spinous  process  of  the  ilium, 
while  the  trochanter  major  has  been  directed 
backwards  on  the  dorsum  ilii. 

It  is  rather  strange  that  a  relative  position  of 
the  bones  of  the  hip-joint,  so  different  from 
what  has  been  observed  in  the  ordinary  dis- 
location upwards  on  the  dorsum  ilii,  and  one 
so  usually  met  with  in  the  case  of  original  lux- 
ation of  the  hip-joint,  should  have  heretofore 
escaped  observation. 

In  one  of  the  specimens  of  malformation  of 
the  hip-joint  preserved  by  Mr.  Harrison  in  the 
Museum  of  the  University  of  Dublin,  this 
relative  position  of  the  femur  and  the  anterior 
inferior  spine  of  the  ilium  can  be  noticed, 
while  the  trochanter  major  is  placed  posterior 
to  both.  And  in  two  preparations  preserved 
in  the  Richmond  Hospital  Museum,  the  same 
observation  can  be  made, — the  atrophied  heads 
of  the  thigh-bones  are  directed  forwards ;  the 
great  trochanters  lie  behind  these  heads  on  the 
sides  of  the  pelvis. 

These  are  circumstances  important  for  us  to 
keep  in  mind,  when  we  are  considering  the 
diagnosis  of  the  various  affections  of  the  hip- 
joint. 

We  say  that  such  a  remarkable  circumstance 
demands  notice  from  us,  because  in  the  cases  of 
this  affection  we  have  as  yet  observed  in  the  living 
subject,  the  thigh,  leg,  and  foot  of  the  malformed 
limb  has  not  been  so  much  inverted  as  it 
always  is  in  the  ordinary  luxation  upwards  and 
backwards  on  the  dorsum  ilii ;  indeed  in  the 
case  of  a  lad,  named  Hannon,  whom  the  writer 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


783 


has  frequently  examined,  {fig.  308,)  the  thigh, 
leg,  and  foot  were  by  no  means  inverted,  the 
ordinary  aspect  of  the  front  of  the  femur,  patella, 
&c.  was  directed  as  much  forwards  as  it 
naturally  is ;  the  shortening  and  other  signs  of 
luxation  upwards  on  the  dorsum  ihi  existed, 
and,  in  consequence  of  the  emaciated  state  of 
the  limb,  the  relative  position  of  the  head  and 
neck  of  the  femur,  above  adverted  to,  was  easily 
recognized,  when  the  hand  was  laid  upon  the 
head  of  the  bone,  and  a  strong  movement  of 
rotation  outward  was  communicated  to  the  mal- 
formed extremity. 

We  do  not  mean  to  assert  that  in  all  cases 
this  relative  position  of  the  head  and  neck  of 
the  femur  will  be  found  to  exist;  in  this,  as  in 
other  congenital  defects,  much  variety  may  be 
expected  to  be  found.  When  in  these  cases 
the  soft  parts  are  removed,  the  bones  of  the 
pelvis  present  appearances  which  are  remark- 
able enough,  although  we  believe  that  these 
appearances  have  heretofore  escaped  the  obser- 
vation of  anatomists,  who  seem  to  have  confined 
their  attention  to  the  abnormal  condition  of  the 
head  of  the  os  femoris  and  the  acetabulum. 

The  anterior  spines  of  the  ilium,  particularly 
the  inferior,  we  have  usually  found  to  be  directed 
very  much  inwards,  towards  each  other  (fig. 
307);  the  external  iliac  fossa  to  be  more  convex, 
and  the  internal  iliac  fossa  more  concave  than 
usual :  beneath  the  anterior  inferior  spine  we  no- 
tice a  deep  groove  directed  outwards,  through 
which  the  united  tendon  and  fibres  of  the  psoas 
and  iliacus  pass  to  the  lesser  trochanter  of  the 
femur,  which  process  is  always  in  these  cases 
placed  so  much  behind  as  well  as  above  its  nor- 
mal situation.  The  sub-pubic  angle  is  remark- 
ably obtuse,  the  rami  of  the  pubes  and  ischia 
are  very  oblique,  and  the  tuberosities  of  the 
ischia  greatly  everted. 

Fig.  307. 


Many  of  these  which  we  would  call  charac- 
teristic features  of  the  double  congenital  defect 
now  under  consideration  have  heretofore  escaped 


the  notice  of  all  those  who  have  written  on 
"  the  original  luxation"  of  the  hip-joint.  San- 
difort  in  his  Museum  Anatomicum  has,  how- 
ever, given  a  delineation  of  a  pelvis  belonging 
to  a  subject  in  which  he  says  both  hip-joints 
were  found  dislocated :  what  this  author  has 
there  drawn  was  probably  not  understood  in 
his  day,  but  any  one  who  has  seen  many  spe- 
cimens of  the  deformity  we  are  now  endea- 
vouring to  describe,  will  agree  with  us,  we  are 
sure,  in  considering  Plate  lxiv  a  true  repre- 
sentation of  congenital  luxation  in  both  hip- 
joints. 

When  only  one  of  the  hip-joints  is  affected 
we  find  a  lateral  curvature  of  the  spine  to  exist, 
and  the  bones  of  the  pelvis  to  be  in  a  state  of 
atrophy  on  the  malformed  side.  The  portions 
of  the  os  pubis  and  ischium  which  circum- 
scribe the  thyroid  foramen  are  generally  long 
and  slender,  and  the  tuberosity  of  the  is- 
chium is  at  a  greater  distance  from  the  sym- 
physis of  the  pubis  on  the  malformed  than  on 
the  opposite  side. 

Many  of  the  anatomical  characters  we  have 
here  stated  may  be  supposed  to  be  the  gradual 
result  of  causes  acting  from  early  infancy  on 
bones  as  yet  soft  and  cartilaginous.  The  weight 
of  the  body  so  constantly  acting  unfavourably 
on  badly-formed  bones  and  over-distended  liga- 
ments, the  efforts  of  muscles  by  their  repeated 
exertions  endeavouring  to  supply  the  defici- 
encies in  the  ligaments  and  in  the  articular  sur- 
faces of  the  bones,  are  so  many  causes  which 
must  act  on  and  alter  the  direction  of  the  head 
and  neck  of  the  femur,  distort  the  tuberosities 
of  the  ischia,  and  draw  towards  the  middle 
line  the  spines  of  the  ilium;  but  we  may  inquire 
does  the  first  fault  in  these  cases  consist  in  the 
arrest  of  development  in  the  bones?  in  the 
muscles?  or  should  we  look  to  the  nervous 
system  for  the  primitive  source  of  these  intra- 
uterine defects  ?  These  are  inquiries  which  can- 
not, we  believe,  in  the  present  state  of  our  know- 
ledge, be  satisfactorily  replied  to.  Andral  re- 
marks that  in  almost  all  cases  in  which  one  of 
the  cerebral  hemispheres  is  atrophied  we  find 
the  limbs  of  the  opposite  side  less  developed 
than  natural ;  but  he  does  not  venture  to  ex- 
press an  opinion  as  to  whether  the  imperfect 
de/elopment  of  the  brain  is  the  cause  of  the 
malformed  extremity,  or  the  repose  and  want 
of  use  of  the  latter  the  reflected  cause  of  the 
atrophy  of  the  brain.  No  doubt  we  have,  in 
one  solitary  instance  already  quoted,*  shewn 
that  a  congenital  malformation  of  the  left  hip- 
joint  coincided  with  a  deficiency  of  the  cerebral 
convolutions  of  the  right  hemisphere  of  the 
brain,  but  this  coincidence  we  have  reason  to 
believe  must  be  exceedingly  rare. 

Some  surgeons  of  eminence,  whose  opinions 
must  have  considerable  weight  with  the  pro- 
fession, have  stated  it  to  be  their  belieff  that 
"  a  simple  paralytic  condition  of  the  muscles  of 
the  lower  extremity,  as  a  consequence  of  the 
irritation  from  teething  arising  during  infancy," 
is  the  starting  point  of  disease  in  these  cases, 

*  Dr.  Hutton's  case,  Dublin  Journal,  volume  viii 
t  See  Lancet  for  1825-6. 


784 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


and  would  of  course  consider  all  the  pheno- 
mena of  the  malformation  we  have  dwelt  on, 
as  the  mere  consequences  of  the  paralytic  con- 
dition of  the  muscles.  With  such  a  doctrine 
we  are  not  at  all  disposed  to  agree;  in  no  other 
instances  do  we  find  paralysis  produce  similar 
results;  besides,  the  muscles  of  the  hip-joints 
in  many  of  these  cases  seem  in  the  exercise  of 
running  and  leaping  endowed  with  very  ener- 
getic powers  of  action.  It  is  perfectly  clear 
that  to  refer  all  in  these  cases  to  a  paralysis  of 
the  muscles  is  quite  unsatisfactory,  because  the 
abnormal  conditions  of  the  several  structures 
around  the  affected  joints  are  in  these  cases  so 
varied  and  numerous  that  we  feel  that  they 
never  can  be  rationally  referred  to  this  single 
source.  In  some  instances  we  find  a  very  well 
marked  oval  eminence  on  the  side  of  the  pelvis 
for  articulation  with  the  malformed  head  of  the 
femur,  while  no  trace  of  cotyloid  cavity  exists; 
in  some  the  defect  is  slight,  in  others  the  de- 
formity is  great;  thus  the  ligamentum  teres 
may  be  a  long  and  slender  thread  without  vas- 
cularity or  strength  in  some  cases,  in  others  we 
have  seen  it  four  inches  long,  and  at  the  same 
time  of  considerable  breadth ;  while  in  others 
again  no  trace  of  ligamentum  teres  or  head  of 
the  femur  existed,  the  imperfect  representation 
of  a  head  being  retained  by  a  lengthened  cap- 
sular ligament,  supported  by  the  smaller  mus- 
cles around  the  malformed  articulation. 

These  observations  satisfy  us  that  we  cannot 
refer  to  "  paralysis  of  the  muscles  of  the  lower 
extremity  as  a  consequence  of  irritation  from 
teething  arising  during  infancy,"  the  pheno- 
mena that  this  affection  termed  congenital  mal- 
formation of  the  hip-joint  presents. 

We  have  no  doubt  seen  some  instances  in 
which  a  certain  paralytic  tendency  and  other 
congenital  defects  seemed  combined  with  the 
malformation  of  the  hip-joint ;  but  again  we 
have  seen  many  others  in  which  there  was  no 
paralytic  tendency,  and  in  which  no  other  de- 
fect than  a  double  congenital  luxation  of  the 
hip-joint  existed ;  and  in  Dupuytren's  twenty- 
six  cases  no  mention  is  made  of  paralysis,  nor 
of  atrophy  of  the  cerebral  convolutions. 

We  confess  we  are  glad  to  feel  ourselves  able 
successfully  to  oppose  the  hopeless  idea  of  pa- 
ralysis of  the  muscles  being  in  fault,  because 
we  have  reason  to  believe  that  mechanical  treat- 
ment of  the  malformed  hip-joint  has  succeeded, 
when  early  applied,  in  lessening  the  infirmity. 
The  idea  of  paralysis  of  the  muscles  being  the 
root  of  the  evil,  precludes  all  hope  of  mecha- 
nical treatment  being  at  all  serviceable  to  these 
unfortunate  individuals. 

History  of  a  case  of  congenital  malformation 
of  the  lef  t  hip-joint,  with  the  anatomical  exa- 
mination of  the  articulation. — A  man  named 
John  North,  aet.  31,  of  weak  intellect,  was 
admitted  under  the  care  of  Dr.  Hutton,  July 
1835,  into  the  Richmond  Hospital;  he  was 
afflicted  with  a  most  severe  form  of  inflamma- 
tion of  the  larynx,  trachea,  and  lungs.  I  was 
asked  to  visit  him,  and  report  my  opinion  as  to 
whether  the  operation  of  tracheotomy  should 
be  performed,  or  whether  such  a  measure  would 
be  calculated  to  relieve  the  urgent  symptoms  of 


dyspnoea  which  seemed  in  this  case  to  threaten 
suffocation.  While  I  was  examining  the  pa- 
tient he  wished  to  get  out  of  his  bed,  and  then 
I  noticed  that  besides  having  an  atrophied  and 
contracted  state  of  the  left  forearm  and  wrist, 
his  left  lower  extremity  was  deformed,  and 
seemed  much  shorter  than  the  opposite  limb. 
Upon  even  a  very  superficial  view  of  this  left 
hip-joint  and  the  position  of  the  limb,  all  the 
more  obvious  features  of  a  dislocation  up- 
wards and  backwards  on  the  dorsum  ilii,  were 
recognized.  Upon  inquiry  it  was  ascertained, 
as  far  as  could  be  from  such  a  patient  and  from 
his  ordinary  attendants,  that  the  hip-joint  had 
never  suffered  any  accident,  and  that,  although 
he  had  issues  inserted,  he  never  had  had  any 
acute  disease  or  suffering  in  the  deformed  hip, 
which  deformity,  with  the  contraction  of  the 
upper  extremity,  was  coeval  with  their  earliest 
recollections  of  him. 

I  agreed  with  those  in  consultation  on  the 
case  that  the  state  of  the  lungs  would  speedily 
bring  about  the  death  of  the  patient,  and  that 
no  operation,  such  as  tracheotomy  or  laryngo- 
tomy,  should  be  resorted  to.  I  also  expressed 
my  conviction  that  the  left  hip-joint  presented 
a  very  fine  illustration  of  the  abnormal  state  of 
this  articulation,  which  Dupuytren  and  others 
had  described  as  a  congenital  or  original  luxa- 
tion of  the  hip.  The  next  day  the  patient  died 
of  the  inflammatory  affection  of  the  chest,  and 
a  post-mortem  examination  was  made  by  Dr. 
Hutton,  at  which  Mr.  Smith  and  the  writer 
were  present.  There  were  observed  the  same 
appearances  of  luxation  on  the  dorsum  ilii 
as  before  noticed ;  the  body  being  held  up  and 
maintained  in  the  erect  posture,  the  pelvis  was 
seen  to  be  very  oblique  and  elevated  towards 
the  malformed  side,  the  left  lower  extremity 
seemed  three  inches  shorter  than  the  right  or 
perfectly  formed  limb,  but  on  measurement  it 
was  plain  that  the  deformed  limb  was  not 
really  shortened,  but  had  merely  ascended  on 
the  dorsum  ilii.  The  trochanter  major  (natu- 
rally on  a  level  with  the  horizontal  ramus  of 
the  pubis)  was  elevated  two  inches  above  this 
bone.  In  the  prominence  and  elevation  of  the 
great  trochanter,  in  the  semiflexion  and  adduc- 
tion of  the  limb,  in  the  circumstance  of  the 
motions  of  rotation  and  abduction  being  li- 
mited,— in  all  these  the  case  nearly  resembled 
the  ordinary  luxation  on  the  dorsum  ilii,  whe- 
ther produced  by  accident  or  the  result  of  an 
old  caries;  but  the  history  of  the  case  was  op- 
posed to  either  of  these  conjectures,  and  the 
marks  of  issues  placed  there  through  ignorance 
were  not  to  mislead  us,  or  induce  us  to  alter 
our  opinion  already  expressed,  as  we  were  well 
aware  that  in  almost  all  the  cases  seen  by  Du- 
puytren similar  evidences  of  surgical  ignorance 
of  the  true  nature  of  the  affection  had  existed. 
Besides  the  unusual  prominence  and  elevation 
of  the  trochanter  major  already  mentioned,  the 
head  of  the  femur  could  itself  be  plainly  enough 
felt,  when  a  movement  of  rotation  outwards  was 
given  to  the  shaft  of  the  bone;  but  when  the 
limb  was  forcibly  elevated  or  extended,  even 
now  in  the  dead  subject,  its  range  of  move- 
ment of  ascent  and  descent  was  not  more  than 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


785 


half  an  inch  ;  in  this  particular  this  case  dif- 
fered from  those  given  by  Dupuytren,  because 
in  his  cases  the  range  of  motion  of  ascent  and 
descent  of  the  head  of  the  femur  on  the  os 
innominatum,  which  could  be  communicated, 
amounted  to  two  inches.*  The  body  having 
been  placed  on  its  face,  and  the  integuments 
removed  from  the  glutaeus  maximus,  this 
muscle  looked  somewhat  paler  in  its  colour 
than  natural,  its  lower  margin  (which  in  the 
natural  state  has  a  descent  of  obliquity  amount- 
ing to  three  inches)  was  placed  nearly  trans- 
versely. When  this  muscle  was  removed,  the 
trochanter  major  presented  itself ;  it  lay  on  the 
dorsum  of  the  ilium,  near  to  the  ischiatic 
notch,  above  the  pyriformis  and  below  the 
range  of  the  glutaei  (medius  et  minimus),  which 
were  in  a  state  of  atrophy.  The  head  of  the 
femur,  smaller  than  usual,  was  in  advance  of 
the  great  trochanter,  and  was  placed  immedi- 
ately external  to  the  anterior  inferior  spinous 
process  of  the  ilium,  and  was  here  covered 
immediately  by  the  capsular  ligament  and  some 
scattered  fibres  of  the  lesser  glutaei :  the  tensor 
vaginee  femoris  lay  in  front  of  the  head  of  the 
bone. 

The  pyriformis  and  quadratus  were  very 
oblique  m  their  course,  passing  upwardsand  out- 
wards :  all  the  muscles  in  the  front  of  the  thigh, 
such  as  the  pectinalis  and  other  adductors,  passed 
from  the  os  pubis  outwards  with  a  degree  of  ob- 
liquity three  or  four  inches  less  than  natural. 
The  psoas  magnus  was  drawn  a  little  outwards, 
and  its  edges  were  twisted  so  that  the  internal 
edge  was  diiected  backwards  and  its  external 
edge  forwards.  All  the  muscles  of  this  ex- 
tremity were  smaller  and  less  developed  than 
those  of  the  other ;  but  with  the  exception  of 
part  of  the  obturator  externns  which  looked 
fatty,  their  fibres  had  a  natural  appearance. 
There  were  no  marks  of  previous  violent  injury 
or  chronic  disease. 

The  capsular  ligament  was  attached  as  usual 
to  the  circumference  of  the  acetabulum  on  one 
part,  and  to  the  base  of  the  neck  of  the  femur 
on  the  other;  it  was  strong  and  at  the  same 
time  elongated,  so  as  to  allow  the  head  of  the 
femur  to  rest  on  the  dorsum  of  the  ilium,  but 
ligamentary  bands  passed  from  this  part  of  the 
ilium  to  the  external  surface  of  the  capsule, 
where  it  invested  the  head  of  the  femur;  these 
must  have  served  to  strengthen  and  fix  the 
capsule  and  thus  prevent  any  great  range  of 
motion  over  the  ilium.  When  this  capsule 
was  cut  into,  the  head  of  the  femur  was  found 
somewhat  conical  in  its  form  and  much  smaller 
than  usual ;  the  cartilaginous  covering,  thin  and 
of  an  azure  hue,  did  not  form  a  very  uniform 
or  perfect  covering  for  the  head  of  the  bone  ; 
there  seemed  no  deficiency  of  synovial  fluid 
within  the  joint.  The  ii.ter-articular  liga- 
ment or  ligamentum  teres,  as  it  is  called,  pre- 
sented a  very  remarkable  appearance  ;  it  was 
of  unusual  dimensions,  being  more  than  four 
inches  long;  of  a  yellowish  colour  like  tendon, 
and  as  thick  as  the  tendo  Achillis  near  the  os 

*  See  Dr.  Mutton's  account  in  the  Dublin  Jour- 
nal, vol.  viii. 
VOL.  It, 


calcis ;  instead  of  being  firm,  round,  and  thick, 
it  was  soft  and  could  be  easily  spread  out  to 
the  breadth  of  an  inch  :  its  fibres  were  con- 
nected by  means  of  a  thin  transparent  mem- 
brane like  a  synovial  structure.  This  sub- 
stitute for  the  normal  ligamentum  teres  was 
continuous  with  the  cotyloid  ligament,  or  arose 
from  that  part  of  it  which  completes  the  notch 
of  the  acetabulum  within.  From  this  origin  or 
attachment,  the  ligament  passed,  as  it  were, 
from  within  outwards  and  upwards  to  be  at- 
tached to  the  bead  of  the  femur,  presenting  in 
its  course  an  inverted  arch,  the  cavity  up- 
wards and  inwards,  the  convexity  downwards 
and  outwards.  On  its  inferior  surface  it  cor- 
responded to  the  head  of  the  femur,  where  it 
was  hollowed  out  from  before  backwards,  so  as 
to  accommodate  itself  to  the  head  of  the  bone, 
for  which  it  formed  a  kind  of  cup  which  follow- 
ed the  movements  of  the  femur,  alibrding  it 
always  a  receptacle  as  the  inter-articular  carti- 
lage does  for  the  condyle  of  the  lower  jaw.  This 
broad  ligament  had  no  connexion  by  synovial 
folds  or  fibrous  productions  with  the  bottom  of 
the  acetabulum.  The  cotyloid  ligament  was 
flattened  out  round  the  brim  of  the  acetabulum, 
and  was  otherwise  imperfect:  the  fatty  and 
vascular  cellular  structure  named  Haversian 
gland  existed  in  rather  large  quantity. 

When  a  comparative  view  of  the  bones  of  the 
pelvisand  lowerextremity  of  each  side  was  taken, 
it  was  manifest  that  the  left  lower  extremity  was 
in  a  state  of  atrophy,  that  the  thigh-bone  was 
straight  and  slender,  and  that  the  atrophy  ex- 
tended downwards  to  the  bones  of  the  leg, 
and  included  also  the  whole  of  the  left  os 
innominatum  ;  the  anterior  spines  and  crest  of 
the  ilium  were  inverted,  the  internal  iliac  fossa 
was  much  deepened,  and  the  external  surface 
of  the  ilium  rendered  more  convex  than  usual. 
The  rami  of  the  os  pubis  and  ischium  seemed 
more  attenuated  and  slender  than  those  of  the 
opposite  side,  and  the  foramen  ovale  wider. 
The  circumference  of  the  acetabulum  of  this 
side  included  nearly  as  large  a  space  as  usual, 
but  the  upper  and  outer  portion  of  its  brim  or 
its  supeicihum  was  deficient.  This  cavity  was 
shallow,  its  surface  scabrous  or  uneven,  and 
was  no  where  invested  with  cartilage;  a  flattened 
surface  above  it  marked  the  point  of  habitual 
contact  of  the  head  of  the  femur  and  ilium : 
the  bone  was  not  excavated  in  this  situation  to 
receive  the  head  of  the  femur,  which  was  re- 
tained here,  as  already  mentioned,  by  liga- 
mentous bands,  which  extended  from  this  part 
of  the  ilium  to  the  external  surface  of  the  cap- 
sular ligament.  The  femur,  it  has  been  said, 
was  atrophied  at  this  side  and  slender,  but  it 
was  of  the  same  length  as  the  opposite  bone, 
diminished  only  in  the  circumference  of  the 
shaft.  The  axis  of  the  head  and  neck  was 
directed  from  the  shaft  of  the  bone  upwards 
and  inwards,  but  it  was  straighter,  and  its  di- 
rection was  by  several  degrees  more  forward 
than  natural. 

As  we  have  detailed  this  case  merely  as  an 
illustration  of  the  congenital  malformation  of 
the  hip,  and  do  not  wish  here  to  enter  into 
minute  particulars  as  to  the  morbid  appear- 

3  F 


78G 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


ances  which  the  post-mortem  examination  fur- 
ther disclosed,  we  merely  state  that  evidences 
of  diffuse  inflammation  of  the  mucous  and 
submucous  tissues  of  the  pharynx  and  larynx, 
with  purulent  infiltration  in  the  submucous 
tissue,  existed  with  extensive  bronchitis,  as 
well  as  splenization  of  the  lungs.  It  was  more- 
over discovered  that  the  right  hemisphere  of 
the  brain  was  deficient,  and  that  a  cyst  five 
inches  in  length  and  between  two  and  three  in 
its  transverse  diameter  occupied  the  interval 
(which  was  an  inch  in  depth)  between  the  sur- 
face of  the  atrophied  brain  and  interior  of  the 
calvarium ;  this  cyst  was  filled  with  limpid 
serum. 

The  whole  of  the  left  upper  extremity  was 
in  a  state  of  atrophy,  flexed  at  the  elbow  and 
wrist-joints,  and  the  forearm  and  hand  were 
rigidly  pronated. 

A  case  of  congenital  luxation  of  the  left  hip- 
joint  very  similar  to  the  foregoing  was  under  the 
writer's  observation  for  some  time  as  an  out-pa- 
tient of  the  Richmond  Hospital.  This  lad  was 
on  different  occasions  seen  and  prescribed  for 
by  Dr.  Ilutton,  who  first  recognized  the  nature 
of  the  case,  and  the  other  surgeons  of  the  insti- 
tution. His  name  was  Martin  Hannon ;  he  was 
a  labourer,  setat.  19  years.  In  his  ordinary 
attitude,  standing,  the  spine  was  curved  laterally 
to  the  well-formed  side,  so  that  the  line  of  gra- 
vity seemed  to  pass  to  the  ground  through  the 
centre  of  the  right  or  well-formed  thigh  and 
leg  :  on  this  side  the  pelvis  was  depressed,  and 
on  the  opposite  side  elevated,  so  that  the  left 
lower  extremity  appeared  three  inches  shorter 
than  the  right.  The  oblique  position  of  the 
pelvis  above  alluded  to  accounted  for  much  of 
this  apparent  shortening,  which  nevertheless, 
by  accurate  measurement  from  the  spine  of 
the  ilium  to  the  inner  malleolus,  was  proved 
to  be  real  to  a  certain  extent,  viz.  one  inch  and 
a  half.  Next  to  the  shortening  of  the  limb, 
the  most  remarkable  circumstances  which 
caught  our  attention  were  the  prominency  and 
elevation  of  the  trochanter  major,  which  was 
found  to  be  two  inches  above  the  horizontal 


Fig.  308. 


ramus  of  the  pubis.  The  trochanter  major  was 
also  behind  its  usual  situation  (Jig.  308).  The 
hip-joint  possessed  a  certain  degree  of  the  mo- 
tions of  flexion  and  abduction,  and  when  the 
patient  was  directed  to  extend  the  thigh  back- 
wards, the  motion  about  the  sacro-lumbar  arti- 
culations seemed  preternaturally  free.  When 
the  hand  was  placed  on  the  left  hip-joint,  the 
head  of  the  femur  could  be  felt  plainly  to  be 
situated  in  a  very  unusual  position,  namely, 
forwards  and  upwards,  close  to  the  anterior 
inferior  spine  of  the  ilium,  and  in  advance 
of  its  neck  and  the  great  trochanter,  which 
lay  towards  the  ischiatic  notch :  if  now  a 
motion  of  rotation  outwards  were  commu- 
nicated to  the  femur,  the  trochanter  major 
moved  backwards,  while  the  head  of  the  femur 
rolled  forwards  and  outwards;  and  so  very  thin 
was  the  patient  that  the  head  of  the  bone  could 
be  seen  and  easily  felt  moving  in  this  novel 
situation.  The  deformed  thigh  was  at  its  upper 
part  thrown  much  outwards  (jig.  308),  and  to  re- 
cover, as  it  were,  this  deviation  outwards  above, 
it  passed  much  inwards  towards  its  lower  ex- 
tremity; the  thigh  and  leg  were  cold  and 
atrophied,  and  the  poor  lad  had  also  that  mal- 
formation of  the  ankle  called  valgus. 

He  walked  with  the  assistance  of  a  stick, 
and  in  consequence  of  the  double  defect  of  the 
left  hip-joint  and  ankle  very  imperfectly. 

The  sound  limb,  which  seemed,  in  standing, 
to  bear  the  whole  weight  of  the  body,  was 
very  muscular,  and  was  larger  in  proportion 
than  to  be  expected,  when  compared  with  the 
left  or  deformed  leg,  thigh,  chest,  and  upper 
extremities,  which  last  presented  no  peculi- 
arities. 

Such  were  the  notes  the  writer  had  taken  of 
this  case  in  December  1837,  when  the  lad  ap- 
plied to  him  at  the  hospital  to  be  relieved  of 
an  indolent  ulcer  he  had  on  the  weak  limb. 
In  the  beginning  of  the  spring  of  this  year 
he  became  affected  with  phthisis,  and  died  of 
that  disease  in  the  VVhitworth  Hospital  on  the 
12th  June,  1838.  Mr.  Smith  had  a  cast  taken 
of  the  lower  part  of  the  body,  pelvis,  and  lower 
extremities,  which  is  preserved  in  our  Museum. 
The  interior  of  the  thorax  presented  the  usual 
effects  of  phthisis. 

Left  hip-joint. —  The  muscles  around  the 
joint  were  remarkably  pale  and  greatly  attenu- 
ated ;  they  held  the  same  position  relatively  to 
the  head  of  the  bone,  as  in  the  preceding  case 
of  North,  but  they  were  more  atrophied ; 
in  many  places  all  appearance  of  muscular 
fibre  was  lost,  and  its  place  supplied  by  a 
yellow  fatty  fibrous  tissue.  The  muscles  of 
the  rest  of  the  extremity,  particularly  the  gas- 
trocnemius and  solceus,  were  in  a  similar  con- 
dition. The  sciatic  nerve  had  not  a  very 
healthy  aspect;  it  was  yellowish;  and  its  fibres, 
though  firm,  were  more  loosely  connected  than 
usual. 

The  capsular  ligament  was  remarkably  thick, 
and  was  lined  on  its  interior  or  synovial  surface 
with  a  very  red  vascular  membrane,  like  scarlet 
cloth.  The  internal  ligament  of  the  joint  or 
ligamentum  teres  was  fully  three  inches  long, 
and  much  stronger  than  usual  (Jig.  309);  it 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


787 


Fig.  309. 


grew  to  the  cotyloid  ligament  at  the  notch,  as 
is  usual,  and  had  no  other  connexion  with  the 
acetabulum,  which  contained  no  Haversian 
gland,  and  was  not  lined  by  cartilage.  The  coty- 
loid ligament  was  very  flat  and  imperfect. 

Bones. — -In  the  general  aspect  of  the  bones 
of  the  pelvis  and  of  the  femur,  there  existed  a 
very  striking  resemblance  between  this  case 
and  the  former  detailed.  The  os  innominatum 
of  the  left  or  deformed  side,  together  with  the 
femur  and  other  bones  of  the  left  lower  ex- 
tremity, were  much  smaller  than  the  os  inno- 
minatum and  bones  of  the  right  lower  ex- 
tremity ;  the  former,  besides  being  deformed, 
were  also  in  a  state  of  atrophy  in  circumference 
and  length,  while  the  latter  were  evidently  larger 
and  better  nourished  than  one  would  expect  to 
find  them  in  so  delicate  an  individual.  In  a 
word,  there  was  a  compensatory  growth  of  the 
skeleton  on  the  right  side,  as  it  were  to  make 
up  for  the  deficient  growth  of  the  left  or  mal- 
formed side.  The  head  of  the  right  femur  and 
the  corresponding  acetabulum  were  both  very 
large,  the  right  half  of  the  pelvis  too,  in  all  its 
bony  prominences,  was  well  marked,  and  the 
anterior  spines  of  the  ilium  were  inverted  ;  the 
inter- vertebral  substance  intervening  between 
the  last  lumbar  vertebra  and  base  of  the  sacrum 
was  much  thicker  than  usual. 

Section  II.  Disease. — The  abnormal  ap- 
pearances we  notice  in  the  articulation  of  the 
hip,  produced  by  disease,  are  usually  the  result 
of  inflammation,  which  may  have  been  either 
acute  or  chronic;  arising  either  in  the  synovial 
membrane,  the  cartilage,  or  the  bone.  Indeed, 
in  modern  works  on  the  diseases  of  the  joints, 
we  have  laid  down  for  us  rather  positively  the 
symptoms  and  anatomical  characters  of  syno- 
vitis, chondritis,  and  osteitis  ;  but  much  as  we 
would  wish  to  adopt  an  arrangement  that  the 
pathology  of  Pinel  and  Bichat  would  suggest, 
and  which  comes  commended  to  us  by  the  ex- 
perience of  Brodie,  we  do  not  think  that  this 
arrangement  can  be  strictly  adhered  to.  In 
acute  rheumatic  arthritis,  we  have  the  synovial 
or  fibro-synovial  structures  of  the  articulation 
engaged,  with  little,  if  any,  implication  of  the 
cartilage  or  bone,  but  in  any  of  the  cases  com- 
monly denominated  "disease  of  the  hip,"  the 
inflammation,  as  far  as  our  experience  has  gone, 


never  long  confines  itself  to  any  one  structure 
entering  into  the  composition  of  the  joint.  In 
a  work,  however,  like  this,  the  opinions  of  the 
highest  authorities  on  such  a  question  must  be 
quoted.  According  to  Sir  Benjamin  Brodie,* 
synovitis  coxae,  or  inflammation  of  the  syno- 
vial membrane  of  the  hip-joint,  may  take  place 
in  different  degrees  of  intensity  ;  but  for  the 
most  part  it  has  the  form  of  a  chronic  or  slow 
affection,  which,  while  it  impairs,  does  not  de- 
stroy the  functions  of  the  articulation.  In  the 
hip,  less  frequently  than  in  other  joints,  is  the 
fluctuation  of  the  effused  fluid  perceived,  but 
the  existence  of  swelling  is  sufficiently  evident 
beneath  the  muscles  :  there  is  fulness  of  the 
groin  and  pain,  which  is  not  "  referred  to  the 
knee,  as  in  cases  of  ulceration  of  cartilage,  but 
to  the  upper  and  inner  part  of  the  thigh,  im- 
mediately below  the  origin  of  the  adductor 
longus  ;  the  weight  can  be  borne  on  the  af- 
fected limb,  and  pressure  against  the  heel  gives 
no  pain  ;  this  (the  pain)  is  often  severe,  yet  it 
does  not  amount  to  that  excruciating  sensation 
which  exhausts  the  powers  and  spirits  of  the 
patient,  in  whom  the  cartilages  of  the  hip  are 
ulcerated." 

The  following  case  Sir  B.  Brodie  adduces  as 
an  example  of  inflammation  of  the  synovial 
membrane  of  the  hip,  terminating  in  disloca- 
tion. 

Master  L.,f  being  at  that  time  about  eight 
years  of  age,  was  attacked  towards  the  end  of 
September,  1824,  with  what  was  believed 
at  the  time  to  be  inflammation  of  one  of 
the  parotid  glands,  attended  with  a  good  deal 
of  fever ;  after  six  or  seven  days,  and  appa- 
rently in  consequence  of  the  application  of 
cold  lotions  to  the  cheek,  the  inflammation  left 
the  parotid  gland,  and  attacked  one  shoulder  and 
arm  ;  and  at  the  end  of  two  or  three  days  more 
it  left  the  shoulder  and  attacked  one  of  the  hips. 
For  six  or  eight  weeks  he  suffered  most  severely 
from  pain  referred  to  the  inside  of  the  thigh, 
extending  from  the  pubes  as  low  down  as 
within  two  or  three  inches  of  the  inner  con- 
dyle of  the  femur,  and  attended  with  a  great 
deal  of  fever.  There  was  no  pain  in  the  knee. 
The  surgeon  who  was  then  in  attendance  ap- 
plied leeches  to  the  hip,  lotions,  &c.  &c,  and 
afterwards  made  an  issue  with  caustic  behind 
the  great  trochanter.  The  fluctuation  of  fluid 
was  perceived  at  the  posterior  part  of  the  hip ; 
and  it  was  supposed  that  an  abscess  had 
formed  ;  however,  no  puncture  was  made,  and 
the  fluid  gradually  became  absorbed.  In 
March,  1825,  Master  L.  was  sufficiently  well 
to  be  able  to  walk  about,  but  it  was  discovered 
that  the  limb  was  shortened.  In  November, 
1825,  Sir  B.  Brodie  was  consulted  respecting 
him  ;  at  this  time  there  were  all  the  marks  of  a 
dislocation  of  the  hip  upwards  and  outwards, 
the  limb  was  shortened,  the  toes  turned  in- 
wards, and  the  head  of  the  femur  was  distinctly 
to  be  felt  on  the  posterior  part  of  the  ilium, 
above  the  margin  of  the  acetabulum. 

Now,  if  we  may  be  permitted  to  give  an 

*  On  Diseases  of  the  Joints,  3d  edit, 
t  Case  XI.  Brodie,  page  51,  3d  edition. 

3  F  2 


788 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


opinion  as  to  this  case,  we  would  cer- 
tainly question  much  the  correctness  of  the 
conjecture,  that  the  inflammation  of  the  hip- 
joint  was  altogether  limited  to  the  synovial 
membrane :  no  doubt,  so  far  as  the  hip  was 
concerned,  the  inflammation  began  in  the  syno- 
vial structures  ;  but  who  can  doubt  that  in  this 
case  the  cartilages  became  secondarily  en- 
gaged, that  the  acetabulum  itself  was  after  a 
time  implicated,  and  that  an  abscess  had 
formed  ?  For  our  parts,  we  have  little  doubt 
that  all  the  structures  entering  into  the  compo- 
sition of  the  articulation  were  implicated  in  the 
inflammation  of  the  joint. 

It  has  been  above  stated,  as  the  opinion  of 
the  author  now  cited,  that  synovitis  has  for  the 
most  part  the  form  of  a  chronic  affection,  but 
as  a  proof  that  a  disease,  apparently  slight, 
and  of  a  part  no  way  concerned  in  the  vital 
functions,  may  produce  such  a  degree  of  dis- 
turbance of  the  constitution  as  rapidly  to  occa- 
sion death,  he  adduces  the  following  case.* 
Sir  B.  Brodie  considers  it  a  case  of  inflam- 
mation of  the  synovial  membrane,  (synovitis 
coxa?,)  which  ran  its  course  to  a  fatal  termina- 
tion in  the  short  space  of  a  week. 

A  young  lady,  nine  years  of  age,  being  at 
play  on  the  1st  of  January,  1808,  fell  and 
wrenched  her  hip ;  she  experienced  so  little 
uneasiness,  that  she  walked  out  on  that  day 
as  usual;  in  the  evening  she  went  to  a 
dance,  but  there  was  seized  with  a  rigor,  was 
carried  home,  and  put  to  bed.  Next  morning 
she  was  much  indisposed,  and  complained  of 
pain  in  the  thigh  and  knee ;  on  the  following 
day  she  had  pain  in  the  hip,  and  was  feverish. 
These  symptoms  continued  ;  she  became  deli- 
rious, and  died  just  a  week  from  the  time 
of  the  accident.  On  inspecting  the  body  on 
the  following  day,  the  viscera  of  the  thorax  and 
abdomen  were  found  in  a  perfectly  healthy 
state.  The  hip-joint  on  the  side  of  the  injury 
contained  about  half  an  ounce  of  dark-coloured 
pus,  and  the  synovial  membrane,  where  it  was 
reflected  over  the  neck  of  the  femur,  was 
destroyed  by  ulceration  for  about  the  extent  of 
a  shilling-.  This  was  an  awful  case,  and  such, 
fortunately,  are  rare  ;  however  it  has  been  our 
lot  to  witness  some  very  similar  in  their  course 
and  unhappy  termination,  and  we  have  always 
looked  upon  them  as  specimens  of  that  terrible 
disease  "diffuse  inflammation." 

The  next  case,  No.  XVI.  in  Sir  B.  Brodie's 
work,f  vve  look  upon  exactly  in  the  same  light. 
The  following  the  writer  saw  under  the  care  of 
his  lamented  friend,  the  late  Dr.  M'Dowd. 

Synovitis  coxa  with  periostitis  succeeding  to 
a  full  oh  the  hip — deutli  in  eight  days. — Peter 
Neale,  at.  12,  admitted  into  the  Richmond 
Surgical  Hospital,  January  11,  1833.  Four 
days  previous  to  admission  he  fell  from  a  wall 
of  moderate  height,  on  the  left  hip,  which  was 
so  much  contused,  that  he  was  unable  to  stand 
upon  the  limb,  and  was  carried  home.  The 
pain  and  constitutional  disturbance  increased 
■daily  ;  on  admission  it  was  found  that  the  left 

*  Case  XV.  p.  64,  3d  edit, 
t  Page  65,  3d  edition. 


hip-joint  was  very  tense  and  swollen  ;  the  pain 
was  so  excruciating  that  he  was  unable  to  move 
in  bed  without  assistance;  his  countenance 
anxious,  sunken,  and  expressive  of  intense  suf- 
fering, tongue  furred,  black  sordes  on  his  teeth  ; 
he  was  delirious,  and  screamed  without  inter- 
mission ;  his  hip  became  more  tender,  tense, 
and  swollen  ;  he  also  now  complained  of  pain 
in  the  right  shoulder  and  elbow.  To  these 
symptoms  succeeded  drowsiness,  tendency  to 
coma,  occasional  muttering  delirium  ;  he  now 
had  a  peculiarly  wild  and  frightened  look. 
He  died  on  the  morning  of  the  15th  ;  the 
fourth  from  his  admission  into  the  hospital, 
and  the  eighth  from  the  time  of  the  fall  on  the 
hip.  The  post-mortem  examination  took  place 
four  hours  after  death.  On  cutting  through  the 
left  glutaeal  muscles,  matter  issued  from  nu- 
merous small  points  ;  the  muscular  fibres  were 
of  a  deep  red  colour  ;  the  periosteum  was  de- 
tached from  the  entire  of  the  ilium  by  a  quan- 
tity of  dark  brown  pus,  which  passed  through 
the  great  sciatic  notch,  and  separated  the  mem- 
brane from  the  whole  concavity  of  the  bone, 
which  was  of  a  pink  colour ;  the  fluid  had 
passed  through  a  small  ulcerated  opening  in 
the  capsule  of  the  joint  from  the  cotyloid 
cavity;  small  portions  of  lymph  were  found  on 
the  head  of  the  bone,  and  the  synovial  mem- 
brane, covering  the  fatty  mass  at  the  bottom  of 
the  acetabulum,  bore  evidences  of  acute  inflam- 
mation having  existed  here  ;  and  the  surface  of 
the  synovial  membrane  was  also  covered  with 
lymph.  There  was  no  ulceration  of  the  carti- 
lages. The  right  shoulder-joint  healthy.  In 
the  right  elbow-joint  a  fluid  in  small  quantity, 
resembling  that  which  was  contained  in  the 
hip-joint.* 

Cartilage. — The  inflammation  and  ulcera- 
tion of  the  cartilages  of  the  hip-joint  are  said  by 
Sir  B.  Brodie  to  be  most  frequently  met  with 
in  those  who  have  passed  the  age  of  puberty, 
and  who  are  under  thirty  or  thirty-five  ;  but 
that  they  are  sometimes  seen  in  young  children, 
and  occasionally  in  those  advanced  in  life : 
when  the  cartilage  covering  the  bones  which 
enter  into  the  articulation  of  the  hip-joint  are 
affected,  the  progress  of  the  case  is  slow;  the 
pain  is  at  first  trivial,  the  degree  of  lameness 
slight;  but  as  there  is  no  effusion  of  pus  or 
increased  secretion  of  synovial  fluid,  there  is  no 
appreciable  external  swelling;  but  the  pain, 
the  wasting  of  the  limb,  and  lameness  gra- 
dually increase,  with  the  spasmodic  startings, 
and  abscess  and  dislocation  follow,  as  in  cases 
in  which  the  inflammation  originated  in  other 
tissues.  To  exhibit  the  disease  of  the  cartilage 
where  this  structure  alone  is  engaged,  we  must 
have  some  opportunity  of  witnessing  it  in  an 
individual  who  has  died  of  some  other  com- 
plaint. The  following  case  well  illustrates  the 
opinion  of  the  first  authority  on  such  a  sub- 
ject. 

John  Catmah,  44  years  of  age,  was  admitted 
into  St.  George's  Hospital  on  the  29th  of  Sep- 
tember, 1813,  with  pains  of  the  lower  limb  of 

*  See  Dr.  M'Dowel's  observations  in  the  3d  and 
4th  volume  of  the  Dublin  Journal,  on  Synovitis,  &c. 


ABNORMAL  CONDITIONS  OF  THE  IIIP-JOINT. 


789 


the  right  side,  extending  from  the  hip  to  the 
knee,  and  resembling  the  pains  of  rheumatism. 
He  attributed  these  pains  to  his  having  caught 
cold  about  a  month  before  his  admission.  He 
laboured  also  under  a  complaint  of  his  bowels, 
of  which  he  died  on  the  4th  of  December.  On 
dissection,  no  preternatural  appearances  were 
discovered,  except  in  the  right  hip.  The  cap- 
sular ligament  and  synovial  membrane  were  in 
a  natural  state,  the  cartilages  covering  the  head 
of  the  femur  and  lining  the  bottom  of  the  ace- 
tabulum were  destroyed  by  ulceration  in  about 
one-half  of  their  extent,  and  wherever  the  carti- 
lage was  destroyed  an  ulcerated  surface  of  bone 
was  exposed  ;  the  round  ligament  was  readily 
torn  in  consequence  of  ulceration  having  ex- 
tended to  it  at  the  part  where  it  was  inserted 
into  the  acetabulum.  The  bones  possessed 
their  natural  texture  and  hardness ;  there  was 
no  pus  in  the  joint.  It  was  observed  that  the 
ulcerated  surface  of  the  acetabulum  correspond- 
ed to  that  of  the  femur,  these  surfaces  being 
exactly  in  contact  in  the  position  in  which  the 
patient  had  remained  since  his  admission  into 
the  hospital. 

Mr.  Aston  Key,  from  the  cases  he  had  an 
opportunity  of  examining  of  ulceration  of  the 
cartilage  of  the  hip-joint  in  the  early  stage  of 
the  disease,  is  of  opinion  that  the  ulceration  of 
the  cartilage  is  preceded  by  inflammation  of 
the  ligamentum  teres.  He  adduces  the  follow- 
ing interesting  case. 

A  young  female,  who,  for  six  months  prior 
to  her  death,  had  laboured  under  the  usual 
symptoms  of  chronic  inflammation  of  the  hip- 
joint,  and  when  the  symptoms  had  nearly 
yielded  to  the  treatment  employed,  was  attacked 
with  another  disease,  of  which  she  died. 

The  ligamentum  teres  was  found  much 
thicker  and  more  pulpy  than  usual  from  inter- 
stitial effusion  ;  the  vessels  on  its  investing  syno- 
vial membrane  were  distended  and  large,  with- 
out being  filled  with  injection.  At  the  root  of 
the  ligament  where  it  is  attached  to  the  head  of 
the  femur,  a  spot  of  ulceration  in  the  cartilage 
was  seen  commencing,  as  it  does  in  other  joints, 
by  an  extension  of  the  vessels  in  the  form  of  a 
membrane  from  the  root  of  the  vascular  liga- 
ment. The  same  process  had  also  begun  on 
the  acetabulum,  where  the  ligamentum  teres 
was  attached.'* 

Bone. — The  scrofulous  affection  of  the  hip- 
joint  or  morbus  coxae  of  Ford  is,  according  to 
modern  writers,  a  specimen  of  strumous  osteitis. 
The  disease,  as  far  as  the  hip-joint  itself  is  con- 
cerned, commences  deep  in  the  cancellous 
structure  of  the  bones,  and  in  general  is  re- 
markably slow  in  its  progress. 

While  the  disease  goes  on  in  the  cancellous 
structure  of  the  bones,  before  it  has  extended 
further,  and  while  there  is  no  swelling,  the 
patient  experiences  some  degree  of  pain,  which, 
however,  is  never  so  severe  as  to  occasion  seri- 
ous distress;  it  is  often  so  slight,  and  increases 
so  gradually  as  scarcely  to  be  noticed  ;  after  a 
time  the  external  parts  sympathize  with  those 
within,  and  serum  and  coagulated  lymph  being 

*  SeeMedico-Clururgica]  Transactions,  vol.  xviii. 


effused  into  the  cellular  membrane,  the  joint 
appears  swollen  :  should  the  patient  be  a  child, 
it  not  unfrequently  happens  that  this  swelling 
first  attracts  the  attention  of  the  nurse  or  pa- 
rents. The  swelling  is  puffy  and  elastic,  with 
blue  veins  meandring  over  its  surface,  but 
though  usually  more  in  degree  than  in  those 
cases  in  which  ulceration  of  the  cartilage  occurs 
as  a  primary  disease,  it  is  not  greater  in  ap- 
pearance, because  the  muscles  of  the  limb  are 
not  equally  wasted  from  want  of  exercise  ;  the 
pain  increases,  but  is  not  severe  until  matter 
has  formed,  and  the  parts  over  the  abscess  have 
become  distended  and  inflamed,  but  then  it  is 
immediately  relieved  upon  the  abscess  burst- 
ing. The  skin,  under  these  circumstances, 
assumes  a  dark  red  or  purple  colour,  the  ab- 
scess is  slow  in  its  progress,  and  when  it  bursts 
or  is  opened  it  discharges  a  thin  pus,  with  por- 
tions of  a  curdy  substance  floating  in  it ;  after- 
wards the  discharge  lessens  in  quantity,  be- 
comes thicker  in  consistence,  and  at  last  nearly 
resembles  the  cheesy  matter  which  is  found  in 
scrofulous  absorbent  glands.  In  most  instances 
several  abscesses  take  place  in  succession,  but 
at  various  intervals,  some  of  which  heal,  while 
others  remain  open,  assuming  the  form  of  fistu- 
lous sinuses,  at  the  bottom  of  which  carious 
bone  may  be  distinguished  by  means  of  a 
probe.  The  principal  difference  which  is  to  be 
observed  between  the  symptoms  of  this  affec- 
tion and  that  in  which  the  cartilage  is  primarily 
the  seat  of  inflammation,  is  in  the  degree  or 
amount  of  pain  which  the  palient  endures,  and 
which  is  much  greater  in  the  latter  than  in 
those  cases  where  the  disease  exists  in  the  can- 
cellous structure  of  the  bones.  A  girl  laboured 
under  an  affection  of  the  hip-joint,  in  which 
the  nates  were  flattened,  and  an  abscess  had 
broken  on  the  outside  of  the  thigh,  but  it  was 
observed  she  had  suffered  comparatively  little 
pain.  Under  these  circumstances  she  died, 
and  when,  says  Sir  B.  Brodie,  I  was  about  to 
examine  the  body,  1  observed  to  those  who 
were  present,  that  there  was  little  doubt  but 
that  the  origin  of  the  disease  would  be  found 
to  have  been,  not  in  the  cartilages,  nor  in  the 
bony  surfaces  to  which  they  are  connected,  but 
in  the  cancellous  structure  of  the  bone.  The 
appearances  verified  this  remark  :  the  cartilages 
were  ulcerated  and  the  bones  destroyed  to 
some  extent ;  the  latter  were  soft,  so  that  they 
might  be  cut  with  a  scalpel,  and  on  dividing 
the  articulating  extremity  of  the  femur  longitu- 
dinally, a  considerable  collection  of  thick  pus 
was  found  in  the  neck  of  that  bone  below  the 
head,  which  either  had  not  escaped  at  all,  or 
had  escaped  in  very  small  quantity  by  oozing 
through  the  cancelli  which  were  interposed  be- 
tween it  and  the  cavity  of  the  joint.  The  hip- 
joint  wears  externally  the  peculiar  aspect  of  a 
white  swelling,  and  internally  the  anatomical 
structure  will  be  found  similar.  In  this  disease 
of  the  joints  the  cancellous  structure  of  the 
bones  is  the  part  primarily  affected,  in  conse- 
quence of  which  ulceration  takes  place  in  the 
cartilages  covering  their  articulating  surfaces. 
The  cartilages  being  ulcerated,  the  subsequent 
progress  of  the  disease  is  in.  many  respects  the 


790 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


same  as  where  the  ulceration  takes  place  in 
them  jn  the  first  instance.  Rust  is  of  opinion 
that,  under  the  influence  of  the  disease  in  ques- 
tion, the  head  of  the  bone  becomes  more  volu- 
minous than  in  the  normal  state,  and  that  from 
its  gradual  increase  the  cavity  destined  to  re- 
ceive it  can  no  longer  contain  it;  that  the  cen- 
tre of  the  eminence  becomes  very  vascular  and 
softened,  and  presents  evident  traces  of  inflam- 
mation, which  Rust  thinks  always  begins  in 
the  membranous  medullary  tissue  which  occu- 
pies the  interior  of  the  cancelli  of  the  head  of 
the  bone.  Roche  and  Sanson,  from  whom  we 
have  taken  this  account  of  Rust's  opinion,  add 
that  sometimes  the  articular  head  of  the  bone 
is  not  changed  in  volume,  but  that  the  cavity 
for  receiving  the  head  is  filled  by  a  swelling  of 
the  cartilage  which  clothes  it,  and  by  that  of 
the  cellular  flocculi  or  Haversian  glands. 

Having  stated  the  opinions  of  those  who 
would  wish  to  arrange  and  distinguish  from 
each  other  the  different  morbid  affections  of  the 
hip-joint  according  to  the  different  structures 
they  originate  in,  we  regret  to  feel  obliged  here 
to  express  our  dissent  from  this  arrangement, 
as  we  find  the  greatest  difficulty  in  adhering  to 
it  practically. 

We  have  no  doubt  but  that  the  disease  of 
the  hip,  whether  acute  or  chronic  in  its  attack, 
may  begin  by  an  inflammation  of  the  synovial 
membrane  of  the  joint,  and  that  occasionally, 
particularly  in  scrofulous  subjects,  the  cancel- 
lary  structures  of  the  bones  may  be  the  first 
seat  of  the  local  disease  ;  we  might  even  yield 
an  assent  to  the  opinion  of  some,  that  the  car- 
tilages may  in  rare  cases  be  the  structures  first 
engaged  ;  but  if  we  seek  for  facts  to  convince 
the  mind  of  the  truth  of  all  such  speculations, 
we  shall  find  but  little  that  is  satisfactory  to 
guide  us.  Post-mortem  examinations  seldom 
reveal  to  us  the  state  of  the  joint,  until  the  dis- 
ease has  made  great  ravages,  and  until  several 
structures  have  been  implicated  ;  the  external 
signs  of  synovitis,  chondritis,  and  osteitis,  can- 
not, in  our  judgment,  be  distinctly  recognized 
in  all  cases  in  an  articulation  so  covered  by 
muscles  and  so  remote  from  the  surface  as  the 
hip-joint  is.  We  feel  convinced,  therefore, 
that  in  the  present  state  of  our  knowledge 
the  effects  of  disease  on  the  articulation  of 
the  hip  may  be  best  considered  under  the  fol- 
lowing heads:  1.  acute  arthritis  coxa;  2. 
chronic  strumous  arthritis  coxae ;  3.  chronic 
rheumatic  arthritis  coxae. 

1.  Acute  Art/iritis  coxa. — The  following  case 
presents  an  example  of  an  ordinary  case  of  acute 
arthritis  coxae.  Daniel  Reddy,  aet.18,  a  labourer, 
was  admitted  into  the  Richmond  Hospital  on 
the  11th  of  October,  1838.  He  now  had  all  the 
symptoms  of  a  very  severe  attack  of  acute  inflam- 
mation of  the  hip-joint.  He  stated  that  he  had 
always  been  remarkably  healthy  until  about 
four  weeks  ago,  when  in  consequence  of  having 
lain  for  some  hours  on  damp  grass,  he  had  a 
shivering,  which  was  succeeded  by  fever;  on 
the  following  morning  he  had  severe  pain  deep 
behind  the  great  trochanter ;  he  became  so  very 
lame  and  unable  to  walk  from  the  pain  in  his 
left  hip-joint,  that  he  was  compelled  to  keep 


his  bed ;  he  also  complained  of  pain  in  the 
groin  and  startings  in  the  limb.  When  the 
patient  was  supported  as  far  as  it  was  possible 
in  the  erect  position,  we  observed  posteriorly 
that  there  was  a  remarkable  flatness  and  breadth 
of  die  nates  of  the  affected  hip,  and  that  its 
lower  fold  had  disappeared  ;  there  was  a  gra- 
dual pyriform  tapering  down  of  the  hip  into 
the  thigh,  which  was  already  much  wasted ;  the 
pelvis  itself  was  rotated  on  the  spine,  the  left 
side  being  directed  backwards,  and  the  spinal 
column  much  curved  forwards,  rendering  the 
abdomen  very  prominent  in  this  direction. 
There  was  at  first  an  apparent  elongation  of  the 
limb,  which  soon  became  flexed  on  the  pelvis, 
and  so  strongly  adducted  as  to  cross  the  median 
line,  if  the  term  adduction  can  be  so  applied. 
There  was  great  heat  all  around  the  hip-joint ; 
when  pressure  was  made  either  on  the  great 
trochanter  or  in  the  groin,  it  caused  great  pain 
to  the  patient,  and  if  the  least  movement  was 
communicated  it  seemed  almost  insupportable. 
In  bed  he  lay  on  the  right  or  sound  side,  with 
the  left  side  of  the  pelvis  directed  backwards, 
the  left  thigh  and  leg  both  much  flexed  and 
directed  inwards,  as  already  remarked,  across 
the  middle  line  ;  he  kept  the  limb  by  holding- 
it  grasped  with  both  hands  near  the  knee. 
There  was  some  fulness,  fluctuation,  and  ten- 
derness on  pressure  over  the  left  iliac  fossa,  and 
shooting  pain  passed  down  to  the  knee.  There 
was  constitutional  fever  and  much  general  heat 
of  surface.  To  rest  and  active  treatment  by 
leeching,  blistering,  and  calomel  with  opium, 
his  symptoms  yielded  for  a  time,  then  he  re- 
lapsed, and  such  alternations  occurred  thrice, 
and  then  all  the  urgent  symptoms  subsided. 
In  March  his  fever  and  constitutional  distur- 
bance had  disappeared,  and  from  the  recovery 
of  his  flesh  and  expression  of  countenance,  we 
judged  that  this  attack  had  passed  over,  but 
had  left  him  liable  to  fresh  and  dangerous  re- 
turns of  inflammation  from  the  most  trivial 
causes,  either  local,  such  as  injuries,  or  consti- 
tutional. In  April  there  was  a  shortening  of 
one  inch  and  a  half,  the  foot  of  the  affected 
limb  rested  on  the  instep  of  the  other  in  stand- 
ing, and  in  lying  the  knee  was  supported 
by  a  cushion  placed  above  the  other  knee  ;  ad- 
duction extreme  ;  and  although  the  thigh,  leg, 
and  foot  were  habitually  somewhat  inverted, 
eversion  was  admissible ;  behind  there  was  a 
great  widening  of  the  buttock  and  retraction 
of  the  trochanter  major;  no  fluctuation  of 
matter  could  be  felt  about  the  joint,  nor  had 
he  any  pain  in  the  knee  or  hip. 

Such,  we  imagine,  is  the  more  ordinary 
course  of  acute  arthritis  coxae.  In  this  case 
acute  synovitis  followed  the  lying  on  the  damp 
grass ;  there  was  noticed  an  apparent  elonga- 
tion of  the  limb,  which  was  of  very  short  dura- 
tion, and  was  succeeded  by  a  shortening  at  first 
very  trifling,  scarcely  appreciable,  but  after  a 
month  half  an  inch,  and  at  last  fully  an  inch 
and  a  half.  In  consequence  of  the  very  decided 
elevation  on  the  dorsum  ilii  of  the  great  tro- 
chanter, with  the  habitual  inversion,  flexion, 
and  adduction  of  the  whole  limb,  we  might  be 
led  to  infer  that  in  this  case  the  articular  liga- 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


791 


tnent  and  fibrous  capsule  had  yielded  from 
ulceration,  and  the  muscles  had  dislocated  the 
head  of  the  femur  from  the  acetabulum  on 
the  dorsum  ilii ;  but  the  shortening  was  not 
sudden,  as  we  have  known  it  to  have  been  in 
such  cases,  but  gradual,  nor  by  a  careful  ex- 
amination of  the  dorsum  of  the  ilium,  and 
searching  deeply  behind  the  situation  of  the 
great  trochanter,  could  we  feel  the  head  of  the 
femur  where  it  should  be,  were  it  really  dis- 
located from  the  cavity  of  the  acetabulum,  nor 
by  a  forced  rotation  inwards  of  the  whole  limb 
could  the  head  of  the  bone  be  rendered  mani- 
fest. Our  strongest  reason,  however,  for  con- 
cluding that  the  head  of  the  bone  is  not  really 
luxated  on  the  dorsum  ilii  is,  that  although 
the  foot  may  habitually  be  directed  a  little  in- 
wards, still  the  foot  is  susceptible  of  rotation 
outwards  to  a  greater  extent  than  is  compatible 
with  any  idea  of  the  head  and  neck  of  the 
femur  being  thrown,  as  in  the  ordinary  luxation, 
on  the  dorsum  ilii. 

The  following  case  of  acute  arthritis  coxae 
presents  a  remarkable  example  of  this  affection, 
in  which  the  course  of  the  disease  was  rapid,  its 
symptoms  obscure,  and  death  occurred  sud- 
denly and  unexpectedly. 

On  the  11th  of  January,  1829,  I  was 
requested  by  my  friend  Mr.  Speedy,  then 
one  of  my  pupils  at  the  Richmond  School  of 
Medicine,  to  assist  him  at  the  post-mortem  ex- 
amination of  a  grenadier,  who  died  with  a 
psoas  abscess  rather  suddenly  and  unexpect- 
edly. The  man,  aged  32,  had  been  only  one 
month  complaining  of  pains  about  his  loins 
and  hip-joint,  and  was  only  a  few  days  confined 
to  bed.  The  body  was  thin,  though  not  ema- 
ciated ;  in  the  inguinal  region  a  large  fluctua- 
ting swelling  was  perceived,  which  evidently 
extended  into  the  abdominal  cavity,  and  had 
assumed  the  situation  and  form  of  a  psoas 
abscess.  While  cutting  into  the  cavity  of  the 
abdomen,  pus  was  noticed  to  issue  from  some 
of  the  veins  which  were  divided,  and  particu- 
larly from  the  epigastric.  When  the  abdomen 
was  opened,  we  obseived  that  the  sheath  of  the 
psoas  muscle  was  distended  as  high  up  as  the 
diaphragm,  and  on  puncturing  it  a  quantity  of 
purulent  matter  escaped.  A  second  abscess 
was  discovered  in  the  true  pelvis,  which  ex- 
tended from  the  back  part  of  the  thyroid  fora- 
men to  the  sacrum,  lying  outside  the  bladder 
and  rectum.  We  next  laid  fully  open  the 
sheath  of  the  psoas  muscle,  which  we  observed 
had  not  been  organized  into  the  usual  form  of 
a  cyst,  and  search  was  made  for  some  point  of 
diseased  bone  along  the  spinal  column,  but 
none  was  found  here ;  we  then  directed  our 
attention  to  the  hip-joint;  we  found  the  cap- 
sular ligament  perfect,  except  where  it  arises 
from  the  transverse  ligament  of  the  notch 
near  the  thyroid  foramen.  Here  a  large  per- 
foration existed  in  the  capsular  ligament, 
through  which  the  finger  could  be  passed  on 
through  the  thyroid  foramen  into  the  interior  of 
the  abscess  in  the  true  pelvis  ;  the  sac  of  this 
last  abscess  we  traced  as  high  as  the  bifurcation 
of  the  aorta  and  junction  of  the  common  iliac 
veins  with  the  vena  cava;  here  this  latter  vessel 


was  found  firmly  adherent  to  the  sac,  and  on 
carefully  removing  both  in  connection,  and 
slitting  up  the  vena  cava  posteriorly,  we  had  a 
view  of  a  perforation  in  its  anterior  wall,  close 
to  its  junction  with  the  iliacs;  this  perforation 
was  large  enough  to  admit  a  goose-quill,  and 
established  a  free  communication  between  the 
vein  and  the  cavity  of  the  abscess,  by  which 
blood  and  purulent  matter  had  an  easy  passage 
from  one  to  the  otlier.  How  long  this  commu- 
nication had  existed  we  could  not  ascertain  ; 
but  thus  was  satisfactorily  explained  the  extra- 
ordinary phenomenon  which  had  attracted  our 
attention  in  an  earlier  stage  of  the  dissection, 
viz.  the  issue  of  pus  from  some  of  the  veins  of 
the  abdominal  parietes  which  were  cut  across. 
On  prosecuting  the  examination  still  further, 
we  found  that  close  to  the  anterior  inferior  spine 
of  the  ilium  and  iliopubal  eminence,  where  the 
united  tendons  of  the  psoas  and  iliacus  mus- 
cles pass  over  this  part  of  the  horizontal  ramus 
of  the  os  innominatum,  a  vertical  perforation  of 
the  brim  of  the  acetabulum  existed,  half  an 
inch  deep,  of  a  funnel  shape,  with  its  largest 
part  towards  the  acetabulum,  and  capable  of 
allowing  at  its  smallest  part  a  large  sized  bougie 


Fig.  310. 


to  pass ;  through  this  the  matter  had  passed  up 
and  elevated  the  psoas  muscle  or  distended  its 
sheath,  which  thus  presented  the  ordinary  cha- 
racters of  a  psoas  abscess,  but  which  we  learned 
had  appeared  suddenly  and  without  having 
been  preceded  by  the  usual  premonitory  signs. 
There  was  no  trace  of  cartilage,  Haversian 
gland,  or  synovial  membrane  on  the  acetabu- 
lum; the  round  ligament  was  gone,  and  the 
cartilaginous  covering  of  the  head  of  the  femur 
had  been  removed,  as  well  as  the  synovial 
membrane  of  the  neck  of  this  bone.  The  ex- 
posed surfaces  of  the  bones  were  carious,  but 
the  acetabulum  had  suffered  more  particularly  ; 
it  was  deeper,  but  not  wider  than  usual ;  its 
fundus,  where  formed  by  the  ischium,  was  thin 
as  paper,  but  yet  no  perforation  had  taken 


792 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


place  in  this  part  of  the  cavity,  as  thickened 
periosteum  supported  the  bone,  while  the  ulce- 
rative absorption  was  so  active  in  the  interior 
of  this  cavity,  removing  the  bone,  osseous 
spiculae  or  stalactiform  growths,  such  as  we  are 
familiar  with  as  being  produced  around  scro- 
.i'ulous  joints,  had  been  deposited  around  the 
entire  circumference  of  the  acetabulum  ;  some 
of  these  had  much  narrowed  the  usual  extent 
of  the  obturator  foramen,  at  that  point  where 
matter  had  passed  from  the  joint  into  the  inte- 
rior of  the  pelvis.  The  bones  have  been  mace- 
rated and  preserved  in  the  Richmond  School 
Museum,  and  verify  many  of  the  statements 
made  relative  to  this  very  singular  case. 

What  influence  the  communication  between 
the  cavity  of  the  abscess  and  the  interior  of  the 
vena  cava  had  in  producing  the  fatal  result  in 
this  case,  we  do  not  feel  ourselves  called  upon 
to  determine,  nor  is  this  the  place  to  dwell  on 
this  obscure  subject.  The  usual  phenomena  of 
apparent  elongation  at  first  and  real  shortening 
of  the  limb  afterwards,  either  did  not  exist  or 
were  so  trifling  as  not  to  be  appreciated  in  this 
case,  and  the  disease  ran  its  course  rapidly  to  a 
fatal  termination,  the  head  of  the  bone  remain- 
ing in  its  normal  position  in  the  acetabulum. 
It  was  probably  from  having  witnessed  such 
cases  as  the  foregoing  that  that  experienced 
surgeon,  Boyer,  was  induced  to  make  the  fol- 
lowing remark  : — •"  On  a  observe  un  variete  de 
la  carie  qui  n'attaque  que  le  fond  de  la  cavite 
cotyloide ;  de  sorte  que  ce  fond  seulement  est 
detruit,  tandis  que  ces  bords  restent  intacts  ; 
alors  la  matiere  purulente  de  mauvaise  qualite, 
qui  la  remplit,  se  porte  jusque  dans  le  bassin, 
ou  elle  forme  un  foyer  plus  ou  moins  conside- 
rable ;  dans  ce  cas,  la  maladie  fait  perir  le 
•  sujet,  sans  deplacement  du  femur." 

We  will  adduce  but  one  example  more  of 
the  acute  arthritis  coxas,  with  the  post-mortem 
examination.  •-*:"  !-j  y"!J7->"J^*«~ 

Alexander  Clarke,  ret.  17,  on  admission  into 
the  Richmond  Hospital,  it  was  observed  that 
there  was  much  swelling  about  the  hip-joint; 
the  integuments  over  it  were  tense  and  shining, 
t  ie  glands  in  the  groin  were  swollen  and  very 
tender;  he  suffered  from  pain,  shooting  to  the 
knee  and  spasmodic  startings,  which  awoke 
him  at  night;  he  could  not  permit  the  slightest 
motion  of  the  limb,  which  was  shortened  one 
inch  and  a  quarter;  it  was  habitually  inverted 
and  flexed  on  the  trunk  ;  the  constitutional  dis- 
turbance was  considerable.  From  the  treat- 
ment adopted  he  derived  benefit,  and  a  partial 
recovery  resulted.  He  left  the  hospital,  but 
soon  returned,  in  consequence  of  an  aggravation 
of  all  the  former  symptoms,  caused  by  a  fall  on 
the  diseased  hip.  A  deep  abscess  formed  in 
the  groin  and  extended  under  Poupart's  liga- 
ment; hectic  symptoms  showed  themselves. 
There  were  alternate  diarrhoea  and  attacks  of 
vomiting.  The  abscess  in  the  iliac  fossa  in- 
creased, the  tumefaction  around  the  joint  dimi- 
nished, the  shortening  and  inversion  of  the  limb 
became  greater,  and  oedema  of  the  foot  and  leg 
occurred  ;  he  now  became  suddenly  insensible; 
his  left  arm  was  totally  paralyzed,  while  the 
right  was  convulsed  and  constantly  in  motion  ; 


his  face  too  was  distorted  by  twitchings,  and  he 
passed  his  discharges  involuntarily  ;  he  lay  thus 
for  several  days  and  died,  being  in  all  eighty 
days  ill. 

Post-mortem  examination. — Upon  cutting 
down  to  the  hip-joint  the  capsular  ligament  was 
found  to  have  been  extensively  removed  ante- 
riorly; posteriorly  and  laterally  it  was  not  ulce- 
rated, but  seemed  to  have  been  greatly  length- 
ened and  widened  ;  the  synovial  membrane 
was  lined  with  a  yellowish-green  membrane, 
just  like  what  we  see  investing  the  interior  of 
the  sac  of  an  old  chronic  abscess  ;  the  ligamen- 
tum  teres  and  cartilage,  which  invested  the 
head  of  the  bone,  had  been  removed,  the  bones 
were  rough,  unusually  red  and  vascular,  and 
were  coated  with  yellowish-green  lymph ;  the 
acetabulum  was  much  enlarged,  and  the  head 
of  the  bone  was  drawn  to  the  upper  and  outer 
part.  The  left  iliac  fossa  was  entirely  filled  by 
an  immense  abscess,  lying  between  the  muscle 
and  bone,  passing  down  under  Poupart's  liga-' 
ment  as  far  as  the  lesser  trochanter.  The  iliac 
vessels  and  the  anterior  crural  nerve  were 
pushed  forwards  ;  half  an  inch  below  Poupart's 
ligament  a  process  of  the  abscess  had  passed 
outwards  and  backwards,  which  communicated 
with  the  hip-joint,  and  having  the  muscles  pos- 
terior to  the  joint,  which  were  thinned  and 
matted  together,  to  form  its  wall  in  that  direc- 
tion. In  the  brain  purulent  matter  was  found 
on  the  arachnoid  surface  as  well  as  between  the 
several  convolutions  of  the  right  hemisphere. 
The  neighbouring  portion  of  the  brain  was 
softened  and  vascular;  there  was  no  effusion 
into  the  arachnoid  sac  or  into  the  ventricles.* 

Sometimes  the  acute  arthritis  coxa  is  an 
essential  disease,  and  the  only  one  present  at 
the  time  in  the  constitution,  being  simple  and 
confined  to  the  one  articulation,  as  in  the  case 
of  Reddy  before  quoted.  Sometimes,  however, 
the  acute  inflammation  of  the  hip-joint  is  a 
symptom  of  another  disease.  In  acute  rheu- 
matic fever  the  hip-joint  is,  in  its  turn',  some- 
times severely  visited.  Finally,  the  cases  yet 
published  of  acute  periostitis  and  synovitis 
combined,  and  of  acute  puerperal  rheumatism, 
in  which  the  hip-joint  became  implicated,  need 
not  be  discussed  here.  We  are  of  opinion  that 
such  cases  should  be  looked  upon  as  true  spe- 
cimens of  that  almost  intractable  disease  called 
diffuse  inflammation. 

Anatomical  characters. — FYom  the  post-mor- 
tem examinations  of  cases  of  acute  arthritis 
coxae  which  have  been  hitherto  made,  we  can 
collect  that  all  the  structures  around  the  joint 
are  in  a  state  of  active  vascular  congestion. 
The  synovial  membrane  and  subsynovial  struc- 
ture present  the  ordinary  characters  of  active 
congestion  and  the  results  of  acute  inflamma- 
tion. Sometimes  there  is  an  increased  secretion 
of  synovial  fluid,  and  sometimes,  in  its  stead, 
purulent  matter  distends  the  articulation.  The 
synovial  membrane,  where  it  is  reflected  over 
the  neck  of  the  femur,  has  been  found  de- 

*  See  Dublin  Journal,  vol.  iii.  and  iv„  also  pre- 
paration in  the  Richmond  Hospital  Museum,  which 
the  writer  has  recently  inspected. 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


793 


stroyed  by  ulceration.    Sometimes  the  purulent 
matter  has  been  known  to  have  escaped  from 
the  articulation  by  ulcerated  openings  in  the 
capsule  of  the  joint,  and  to  have  passed  into 
the  pelvis,  and  penetrated  between  the  muscles. 
The  fatty  mass  at  the  bottom  of  the  acetabulum 
has  been  found  swollen,  inflamed,  and  covered 
with  a  membranous  layer  of  lymph,  at  the 
same  time  in  some  of  these  cases  the  neigh- 
bouring periosteum  has  been  found  detached 
from  the  bone,  which  was  redder  than  usual. 
These  are  appearances  which  have  been  noticed 
in  those  who  have  died  of  acute  arthritic  in- 
flammation, whether  it  may  have  arisen  from 
diffuse  inflammation  or  simple  acute  disease 
confined  to  the  one  articulation.     In  acute 
cases,  actual  dislocation  of  the  bones,  we  be- 
lieve, has  not  been  noticed,  as  the  disease  seldom 
arrives  at  its  second  or  third  stage  under  such 
circumstances,  but  the  cartilage  and  synovial 
membranes  have  been  altogether  destroyed,  and 
the  porous  structure  of  the  bones  has  been  ex- 
posed, digital  depressions  have  been  seen  pro- 
duced by  acute  caries  in  the  acetabulum  and 
head  of  the  femur.    The  bones  have  then  pre- 
sented'a  rough  vascular  surface,  and  in  many 
cases  lymph  has  been  found  to  cover  the  con- 
vexity of  the  head  of  the  thigh-bone  and  to  line 
the  acetabulum.    The  head  of  the  femur  some- 
times is  but  little  altered,  either  as  to  form  or 
position,  but  when  the  acetabulum  is  largely 
excavated  by  disease,  the  head  of  the  thigh-bone 
will  be  found  to  be  drawn  by  the  muscles  to 
its  upper  and  back  part.    Even  in  acute  arthri- 
tis coxa  in  the  young  subject,  the  epiphysis  of 
the  head  of  the  femur  has  been  found  de- 
tached.*   The  ligamentum  teres  is  generally 
absorbed  early,  and  the  capsular  ligament  is 
usually  ulcerated  in  some  one  part,  so  that,  on 
the  post-mortem  examination,  the  bones  are 
found  to  be  very  moveable  on  each  other.  They 
are  usually  observed  to  be  highly  vascular,  and 
some  imagine  the  head  of  the  femur  is  en- 
larged.   Ilyperosteotic  depositions  or  stalacti- 
form  productions,  which  are  very  friable,  exist 
around  the  diseased  joint. 

2.  Chronic  strumous  arthritis  coxa. — The 
scrofulous  disease  of  the  hip-joint  is  very  gene- 
rally slow  in  its  progress,  and  is  seldom  seen, 
except  in  persons  who  bear  other  evidences  of 
the  strumous  diathesis ;  there  are  examples  of 
it  occurring  in  individuals  who  have  passed  the 
age  of  thirty  years,  though  generally  seen  in 
those  of  more  tender  years.  This  affection  of 
the  joint,  although  slow  and  insidious  in  its 
attack,  yet  is  attended  with  the  usual  pheno- 
mena of  an  inflammatory  or  sub-inflammatory 
action.  Many  of  the  writers  who  have  de- 
scribed the  "  disease  of  the  hip-joint,"  have 
assigned  to  it  three  periods  or  stages,  as  Ford 
has  done,  while  succeeding  authors  have  added 
to  the  description  of  the  three  stages  of  Ford,  a 
period  which  they  call  the  period  of  the  inva- 
sion of  the  disease.  In  this  their  first  stage, 
there  is  pain  in  the  thigh,  extending  to  the 

*  See  a  preparation  in  the  museum  of  the  Col- 
lege of  Surgeons,  Dublin,  presented  by  the  lute 
Professor  Todd. 


knee,  which  appears  and  disappears  alternately; 
a  marked  weakness  in  the  thigh,  and  a  sense  of 
feebleness  in  the  whole  limb;  the  gait  is  limp- 
ing, and  some  tension  is  felt  in  the  groin.  This 
period  lasts  sometimes  but  a  few  days,  at  other 
times  many  months.  In  the  second  period  the 
limb  is  wasted,  andapparently,  though  not  really, 
elongated  ;  the  trochanter  is  placed  lower  down, 
and  is  more  outward  than  that  of  the  opposile 
side;  the  buttock  is  flattened,  and  its  fold  is 
lower  than  natural ;  the  patient's  lameness  is 
characteristic;  he  moves  the  affected  limb 
round  with  a  shuffling  motion,  the  foot  scraping 
the  ground,  and  he  sometimes  assists  the  eleva- 
tion of  the  thigh  with  his  hand.  At  this  time 
the  knee  is  painful,  and  not  unfiequently  a 
puffy  swelling  appears  in  it,  both  which  cir- 
cumstances often  too  much  attract  the  attention 
of  patient  and  surgeon,  and  divert  it  from  the 
true  seat  of  the  disease.  The  third  period 
is  characterized  by  a  real  shortening  of  the 
limb  ;  this  is  sometimes  sudden,  and  the  im- 
mediate consequence  of  caries  of  the  brim  of 
the  acetabulum  and  luxation  of  the  head  of  the 
femur  upward  and  backward  on  the  dorsum  of 
theilium.  The  shortening  of  the  limb,  however, 
is  more  commonly  gradual,  and  the  consequence 
of  the  slow  ulceration  and  widening  of  the  ace- 
tabulum. 

It  has  of  late  been  truly  observed,  that  the 
luxation  is  not  so  common  as  generally  ima- 
gined, but  when  it  does  occur,  it  usually  takes 
place  in  the  direction  upwards  and  outwards  ; 
when  the  fibrous  capsule  and  other  ligaments 
are  destroyed  by  ulceration,  the  head  of  the 
femur  escapes  by  the  superior  and  posterior 
part  of  the  acetabulum,  and  obeying  the  action 
of  the  glutei  muscles,  it  glides  from  before 
backwards  and  without  inwards  upon  the  con-  ' 
vex  surface  of  the  ilium  ;  the  thigh  is  flexed, 
adducted,  and  turned  with  a  strong  rotation  in- 
wards ;  the  great  trochanter  approaches  the' 
crest  of  the  ilium,  the  muscles  are  raised  up  by 
the  head  of  the  femur,  and  the  buttock  is 
rounded,  and  becomes  very  protuberant  poste- 
riorly. Although  this  is  the  direction  in  which 
the  luxation  usually  takes  place,  still  it  has 
been  noticed  to  have  occurred  in  a  direction 
horizontally  backwards  towards  the  ischiatic 
notch  (Earle).  It  has  also  been  seen  in  the 
direction  downwards  and  inwards  towards  the 
foramen  ovale,  in  which  case  the  limb  is  elon- 
gated and  directed  outwards.  Still  more  rarely 
has  it  been  thrown  upwards  and  inwards  on  the 
horizontal  ramus  of  the  pubis.  In  one  in- 
stance, says  Brodie,  I  have  seen  the  dislocation 
in  the  direction  forwards,  the  head  of  the  femur 
resting  on  the  pubis,  the  knee  and  toes  being 
turned  outwards. 

It  would  be  wrong,  however,  to  suppose  that 
a  true  dislocation  of  the  head  of  the  femur 
from  the  ulcerated  acetabulum  is  a  very  com- 
mon occurrence;  although  all  these  cases, 
above  alluded  to,  have  been  witnessed,  we  be- 
lieve very  frequently  the  shortening  of  the  limb 
in  the  third  and  fourth  stage  of  the  disease 
arises  from  ulceration  and  widening  of  the  ace- 
tabulum and  destruction  of  the  head  of  the 
femur.    The  head  of  the  femur  sometimes  sepa- 


794 


ABNORMAL  CONDITIONS  OF  THE  IIIP-JOINT. 


rates  at  its  epiphysis  from  the  neck  of  the  bone, 
and  the  latter  is  drawn  up,  (fig.  311,)  and  the 

Fig.  311. 


whole  limb  shortened  greatly,  and  the  toes  are 
as  much  everted  as  when  fracture  of  the  neck 
of  the  femur  occurs  from  accident.  The  short- 
ening is  usually,  but  not  invariably,  the  pre- 
cursor of  abscess  ;  when  this  occurs,  the  disease 
is  in  its  fourth  stage.  This  period,  or  that  of 
of  the  formation  of  matter,  is  generally  marked 
by  an  aggravation  of  the  pain,  by  frequent 
spasms  and  startings  of  the  muscles,  by  greater 
wasting  of  the  limb,  occasional  oedema  of  the 
foot,  (which  is  a  very  unpromising  feature,) 
&c.  These  chronic  symptomatic  abscesses  may 
present  themselves  in  various  directions ;  the 
matter  may  remain  for  months  without  under- 
going any  change,  and  even  after  this  be  rather 
suddenly  absorbed,  or  the  pus  may  escape 
through  openings  made  by  nature  or  by  art; 
the  external  orifices  of  these  abscesses  frequently 
degenerate  into  fistulas,  from  which  exfolia- 
tions occasionally  take  place,  and  these  exfolia- 
tions are  sometimes  so  small  as  to  be  almost  sabu- 
lous, sometimes  larger  pieces  come  away  with 
pain  ;  such  are  to  be  considered  not  unfavoura- 
ble indications.  The  writer  has  known  two  ex- 
amples of  the  head  of  the  femur  thus  separated  at 
their  epiphysis  from  the  neck  of  the  bones;  in 
these  cases  the  patients  recovered,  with  the  usual 
deformity.*  Of  the  numerous  situations  around 
the  hip-joint,  in  which  matter  has  been  found 
deposited,  there  is  one  variety  which  demands 
the  special  attention  of  surgeons,  in  conse- 
quence of  the  difficulty  which  has  been  expe- 
rienced in  recognizing  the  disease,  namely,  the 
case  in  which  the  caries  affects  the  bottom  of 
the  acetabulum,  so  that  the  fundus  alone  is  de- 
stroyed.   Sir  B.  Brodie  met  with  one  case, 

*  One  of  these  was  presented  to  him  by  Mr. 
Shaw,  the  surgeon  to  the  Clonard  Dispensary,  and 
is  preserved  in  the  Richmond  School  Museum  ;  the 
other  was  shewn  by  Dr.  Carlile  lately  to  the  Patho- 
logical Society,  Dublin. 


where  in  the  bottom  of  the  acetabulum  there 
was  an  ulcerated  opening,  just  large  enough  to 
admit  a  common  probe,  communicating  with 
an  abscess  within  the  pelvis.  Mr.  Tagart* 
alludes  also  to  a  case  in  which  this  perforation 
exists.    (Figs.  312  and  313.)    Of  such  per- 


Fig.  312. 


Fig.  313. 


*  Lancet,  vol.  i.  1SJ35  and  6,  Jan.  2. 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


795 


forations  the  writer  has  seen  in  different  mu- 
seums a  great  variety :  in  many  instances  the 
opening  is  small,  in  others  of  sufficient  size  to 
admit  easily  the  head  of  the  femur.  These 
cases  are  in  the  beginning  obscure,  and  when 
abscesses  form,  they  are  concealed  within  the 
cavity  of  the  pelvis. 

Anatomical  characters. — 'When  opportuni- 
ties have  occurred  of  examining  the  interior  of 
the  hip-joint  in  those  who  have  died  of  other 
complaints,  this  articulation  being,  at  the  time 
of  death,  in  the  early  stages  of  the  chronic  dis- 
ease we  are  now  considering,  the  adipose 
cellular  mass  which  occupies  the  fundus  of  the 
acetabulum,  the  cellular  structure  which  con- 
nects the  fibres  of  the  inter-articular  ligament, 
the  subsynovial  cellular  tissue  which  surrounds 
the  corona  of  the  head  of  the  femur,  as  well  as 
the  interior  of  the  bones  themselves,  have  been 
found  to  wear  an  unusually  red  appearance 
from  increased  vascularity.  The  cartilage  has 
been  found  softened,  to  have  lost  its  usual 
lustre,  to  be  slightly  elevated,  and  too  easily 
torn  from  the  subjacent  bone ;  in  some  cases 
thinned,  in  others  detached  in  flaps;  in  some 
it  has  presented  a  corroded  appearance,  and 
coinciding  with  these  changes  purulent  matter 
has  been  found  in  the  interior  of  the  joint,  the 
capsular  ligament  thickened,  and  the  lymphatic 
glands  in  the  groin  enlarged.  In  the  anatomi- 
cal examination  of  those  who  have  died  in  the 
advanced  stages  of  the  scrofulous  disease  of  the 
hip,  if  the  patient  have  not  arrived  at  the  age 
of  puberty,  we  find  that  very  frequently  the 
original  portions  of  the  os  innoirnnatum  are 
separated  from  each  other  for  several  lines,  that 
the  epiphysis  of  the  head  of  the  femur  is  com- 
pletely detached  from  the  shaft  of  this  bone ; 
the  greater  and  lesser  trochanters  are  sometimes 
in  very  young  subjects  removed  by  absorption, 
and  evidence  of  devastating  caries  is  found  in 
the  bottom  of  the  acetabulum.    ( Fig.  311.) 

In  some  cases  the  head  of  the  bone  has  been 
found  dislocated  on  the  dorsum  ilii,  previous 
to  which  occurrence  all  the  ligaments  have  been 
destroyed,  the  acetabulum  has  the  superior  and 
posterior  part  of  its  brim  removed  by  caries, 
and  the  bone  thus  abandoned  to  the  action  of 
the  muscles  takes  the  position  it  ordinarily 
does  in  the  common  luxation  upwards  and 
backwards  on  the  dorsum  ilii.  This  complete 
dislocation  is  not  so  common  an  occurrence  as 
generally  imagined ;  there  are,  however,  some 
specimens  of  it  preserved  in  the  museum  of  the 
College  of  Surgeons  in  Dublin.  In  one  pre- 
paration, the  cartilage  of  the  head  of  the  femur 
is  perfect,  the  round  ligament  is  gone  ;  the  fur- 
ther ascent  of  the  head  of  the  bone  on  the  dor- 
sum ilii  seems  principally  restrained  by  the  ob- 
turator muscles  (fig.  314).  The  interesting 
circumstance  in  the  preparation  to  be  noticed 
is,  that  the  acetabulum  is  occupied  to  the  level 
of  its  brim  with  a  very  dense  atheromatous 
matter  or  yellowish  green  lymph,  apparently  an 
uncganized  substance  resembling  what  we  see 
contained  in  crude  scrofulous  tubercles  :  what 
remained  of  the  capsular  ligament  around  the 
neck  of  the  femur  has  been  cut  crucially,  and 
the  everted  edges  of  the  flaps  shew  the  thick- 


Fig.  314. 


ness  of  this  ligament,  increased  to  four  or  five 
lines,  and  caused  by  the  interstitial  deposition 
of  something  like  atheromatous  matter. 

We  have  in  the  foregoing  pages  alluded  to 
the  different  directions  in  which  the  head  of  the 
femur  has  been  found  dislocated  in  the  third  or 
fourth  stage  of  this  disease,  and  should  here 
state  the  anatomical  characters  of  each  luxation, 
but  we  have  not  facts  to  guide  us  in  the  de- 
scription. 

When  a  section  is  made  of  the  bones  enter- 
ing into  the  composition  of  the  hip-joint,  when 
the  patient  has  died  of  this  disease  in  an  ad- 
vanced stage,  they  will  be  found  to  be  softened 
in  the  interior,  and  to  contain  a  fatty  or  a  yel- 
lowish cheese-like  matter  in  their  cells  ;  when 
opportunities  have  occurred  for  examination  in 
an  earlier  stage  of  this  scrofulous  caries,  these 
organs  have  been  generally  found  preternatu- 
rally  red  and  vascular,  (as  before  stated,)  with 
a  deficient  proportion  of  earthy  matter,  admit- 
ting not  only  of  being  cut  with  a  knife  without 
turning  its  edge,  but  yielding  and  being  crushed 
under  very  slight  pressure.  A  modern  au- 
thor,* after  quoting  the  authority  of  Lloyd  on 
scrofula  as  proof  of  the  truth  of  some  of  the 
foregoing  observations,  adds  his  own  opinion, 
"  that  in  simple  inflammation,  uninfluenced  by 
the  scrofulous  diathesis,  particularly  when  it 
becomes  of  a  chronic  character,  bone  is  secreted 
in  abundance,  but  that  the  striking  feature 
in  this  kind  of  inflammation  is,  the  absence  of 
all  secretion  or  deposit  of  bone."  With  the 
latter  doctrine  we  cannot  at  all  agree,  and  must 
conclude  we  do  not  rightly  apprehend  the 

*  Coulson  on  the  Diseases  of  the  Hip-joint, 
Load.  1837,  4to.  p.  39. 


796 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


author,  as  we  have  very  generally  found  osseous 
growths  exterior  to  the  hip-joint  in  the  os  inno- 
minatum  and  femur,  {Jig.  310),  as  the  result 
of  scrofulous  inflammation  of  the  articulation. 
These  growths  are  generally  friable  stalactiform 
productions  which  beset  the  bones,  and  are  to 
be  seen  in  the  numerous  specimens  illustrating 
the  morbid  anatomy  of  morbus  coxa?,  which 
are  contained  in  our  museums  in  Dublin.* 
Notwithstanding  these  osseous  productions  or 
vegetations,  the  bones  are  found  to  have  dimi- 
nished much  in  their  specific  gravity.  I  have 
always  found  them  float  when  thrown  into 
water.  These  growths  are,  however,  only  met 
with  in  the  post-mortem  examination  of  such 
chronic  cases  as  have  manifested  in  their  course 
various  alternations  of  improvement  and  re- 
verses ;  they  are  almost  invariably  found  when 
the  caries  of  the  bones  had  been  arrested,  and 
an  imperfect  attempt  at  anchylosis  had  been 
made. 

We  have  also  opportunities  of  examining 
anatomically  the  hip-joints  of  persons  who  have 
had  this  disease  in  their  youth,  in  whom  it  had 
been  arrested  in  the  second  or  third  stage,  and 
who  had  attained  advanced  life,  and  died  of 
some  other  complaint.  In  some,  besides  the 
bony  growths  already  alluded  to,  we  find  ex- 
amples of  anchylosis  or  of  a  false  joint ;  indeed, 
although  an  absolute  union  and  consolidation 
of  the  bones,  viz.  the  os  innominatum  and 
the  head  of  the  femur  may  not  have  taken 
place,  still  in  most  cases  there  is  very  little 
real  motion  of  the  two  bones  upon  each  other  ; 
the  flexor  and  adductor  muscles  of  the  thigh 
and  hip-joint  are  usually  in  a  state  of  spastic 
contraction  ;  they  admit  of  but  little  increase 
of  flexion  :  whenever  we  attempt  extension,  we 
find  the  thigh  is  readily  brought  down  from 
the  abdomen,  the  lumbar  vertebrae  are  arched 
forwards,  and  this  portion  of  the  spine  and  the 
sacrolumbar  articulation  are  the  seat  of  motion, 
which  often  is  erroneously  referred  to  the  hip- 
joint.  The  os  innominatum  follows  the  head 
of  the  femur  just  as  freely  almost  as  the  scapula 
accompanies  the  various  changes  of  position 
impressed  upon  the  humerus,  when  anchylosis 
of  the  shoulder-joint  has  taken  place.  I  was 
called  upon  about  eight  years  ago  to  examine 
the  body  of  a  woman,  aged  26  years,  who  died 
in  the  Whitworth  Hospital  of  an  acute  disease. 
This  young  woman  had  walked  very  lamely  for 
many  years,  in  consequence  of  her  having  had 
a  most  tedious  and  dangerous  attack  of  hip- 
disease  twenty  years  before  her  death,  but  after 
her  recovery  from  the  first  attack  she  never  had 
any  pain  or  inflammation  in  the  joint ;  there 
were  no  evidences  of  suppuration  ever  having 
occurred  ;  marks  of  issues  were  on  the  nates. 
"When  making  an  examination  of  the  struc- 
tures around  the  articulation  and  of  the  joint 
itself,  the  muscles  were  found  remarkably 
firm,  but  somewhat  paler  than  usual ;  the 
ligamentous  structures  around  the  junction  of 

f  These  osseous  vegetations  we  have  already 
alluded  to  in  this  work,  when  speaking  of  the  chro- 
nic strumous  arthritis  of  the  elbow  :  see  p.  79, 

Elbow-joint,  Abnormal  Anatomy  of. 


the  femur  with  the  os  innominatum  were  very 
strong,  and  so  close  was  the  union  of  the  bones 
that  on  a  superficial  view  we  might  easily  ima- 
gine that  true  bony  anchylosis  had  occurred. 
1  removed  the  bones,  and  they  are  preserved  in 
the  Richmond  School  Museum.  The  whole 
head  of  the  femur  has  been  absorbed,  and  only 
one-fourth  part  of  the  neck  of  the  bone  remains; 
the  place  of  the  cotyloid  cavity  is  supplied  by 
a  rough  scabrous  surface,  of  an  oval  form  trans- 
versely, and  about  one  inch  and  one  line  in  this 
its  longest  diameter  ;  the  two  rough  bony  sur- 
faces with  eminences  and  depressions  con- 
fronted to  each,  and  reciprocally  adapted,  were 
joined  by  a  species  of  strong  fibrous  capsule  ; 
no  motion  whatever  existed  between  these 
bones,  yet  when  the  ligamentous  connexion 
between  them  was  cut,  it  was  evident  that  no 
bony  union  had  taken  place.  In  this  case  the 
false  anchylosis  had  occurred  in  a  very  unfa- 
vourable direction  ;  the  thigh  was  flexed  to  so 
great  a  degree  that  the  knee  was  really  elevated 
above  the  level  of  the  hip-joint,  and  so  much 
adducted  at  the  same  time,  that  the  knee  crossed 
much  the  middle  line.  When  she  stood  up 
straight  on  the  right  and  perfect  limb,  the  left 
heel  did  not  approach  within  twelve  inches  of 
the  ground  :  the  texture  of  the  bones  was  as 
hard  as  iron. 

We  find  in  a  modern  author  the  observation, 
which  must  be  admitted  to  be  correct,  that  true 
bony  anchylosis  of  the  hip-joint  is  rare;  but, 
he  adds,  that  many  pathologists  doubt  that 
such  an  occurrence  ever  takes  place  :  that  the 
many  specimens  of  true  bony  anchylosis  of  the 
hip  we  have  witnessed,  were  all  examples  of 
union  of  bony  surfaces  in  scrofulous  cases,  we 
would  not  wish  to  maintain,  but  we  imagine 
many  of  them  must  have  been  the  result  of  the 
ordinary  hip  disease  cured,  as  it  is  called,  by 
anchylosis.  Sir  Philip  Crampton  has  shewn 
me  a  very  fine  specimen  of  anchylosis  of  the 
hip-joint,  which  very  much  resembles  the  pre- 
paration represented  (fig.  312);  the  acetabu- 
lum had  been  the  principal  seat  of  the  disease; 
it  was  much  widened,  and  the  head  of  the  bone 
was  drawn  towards  its  upper  and  outer  part, 
where  firm  anchylosis  had  taken  place.  In 
this  case  Sir  P.  Crampton  assured  me  the  pa- 
tient had  a  constitution  eminently  scrofulous. 
He  got  well  of  the  hip-disease  by  anchylosis, 
the  thigh-bone  having  been  judiciously  pre- 
served in  a  vertical  direction  during  the  pro- 
gress of  the  cure.  He  walked  afterwards  tole- 
rably well,  but  at  the  age  of  26  became  at- 
tacked with  phthisis,  and  died.  This  case 
proves  that  true  bony  anchylosis  can  occur  in 
the  scrofulous  subject,  and  that  attention  may 
occasionally  overcome  the  disposition  to  exces- 
sive flexion  and  adduction  of  the  limb. 

The  museum  of  the  Richmond  Hospital 
contains  three  specimens,  in  which  the  junction 
of  the  os  innominatum  with  the  femur  is  as 
solid  as  if  they  formed  but  one  bone,  and  a 
vertical  section  through  the  united  bones  shews 
as  free  a  communication  of  the  cells  of  the 
cervix  femoris  and  those  of  the  os  innominatum 
as  if  these  bones  had  never  been  separately 
formed.    These  seem  to  have  been  examples 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


797 


of  early  affections  of  the  hip-disease,  in  which 
little  or  no  displacement  of  the  head  of  the 
femur  occurred. 

The  acetabulum,  we  know,  is  generally 
widened  in  this  disease,  and  the  head  of  the 
femur  is  drawn  upwards  and  outwaids  ;  if  at 
this  period  the  inflammation  be  arrested,  true 
bony  anchylosis  may  occur ;  and  if  a  happy 
direction  can  be  given  to  the  shaft  of  the  femur, 
a  very  useful  limb  may  remain,  even  though 
the  hip-joint  itself  has  lost  all  motion ;  the 
sacro-lumbar  joint  and  the  neighbouring  inter- 
vertebral structures  admit  of  much  freedom  of 
motion. 

In  examining  anatomically  the  hip-joints  of 
those  who,  having  had  the  chronic  scrofulous 
disease  of  this  articulation  in  their  youth,  and 
have  recovered  and  lived  for  years,  though 
lame,  in  these,  instead  of  anchylosis,  we  find 
a  false  joint  is  formed.  Of  this  imperfect  cure 
of  hip  disease  we  have  seen  some  examples, 
and  we  possess  one  remarkable  specimen  of  it. 
In  this  the  acetabulum  was  altogether  removed, 
and  a  triangular  space,  encircled  by  a  rounded 
brim  covered  with  a  compact  stratum  of  bone, 
existed.  The  removal  of  the  neck  of  the  femur 
was  so  complete  that  a  plane  or  rather  concave 
surface  corresponded  to  the  inner  side  of  the 
trochanter  major,  from  which  the  neck  of  the 
bone  naturally  arises. 

It  has  been  stated  that  luxation  on  the  dor- 
sum of  the  ilium  sometimes  happens  as  a  con- 
sequence of  chronic  disease  of  the  joint;  some- 
times the  disease  which  carried  away,  in  this 
instance,  the  borders  of  the  acetabulum,  seems, 
as  it  were,  to  have  been  transferred  to  the  new 
surface  of  the  os  innominatum  with  which  the 
head  of  the  femur  came  in  contact,  and  we  find 
the  process  of  ulceration  has  even  continued  its 
course  ;  again  it  sometimes  happens  that  an- 
chylosis or  a  false  joint  has  been  formed. 

Albers  and  Rust  have  described  the  change 
which  the  bones  of  the  pelvis  undergo  in  their 
form  and  situation.  The  pelvis,  in  those  who 
have  for  a  long  time  gone  lame,  is  pushed  up- 
wards, and  the  sacrum  is  flat  and  straight.  In 
a  few  cases,  however,  it  is  more  curved  than  in 
the  natural  state ;  the  coccyx  is  bent  strongly 
forwards,  and  the  connexion  of  the  last  lumbar 
vertebra  with  the  sacrum  forms  a  right  angle  ; 
the  ilium  of  the  affected  side  stands  higher,  and 
has  in  general  a  perpendicular  direction,  and 
more  of  a  triangular  form  ;  the  external  surface 
is  smooth,  whilst  the  iliac  fossa  appears  more 
hollowed  than  usual ;  this  hollowing  probably 
depends  on  the  action  of  the  iliacus  intern  us, 
which  is  greater  than  that  of  the  gluta;i.  The 
horizontal  ramus  of  the  pubes  often  seems 
lengthened  and  lower  than  in  the  natural  state, 
and  the  ischium  is  usually  drawn  outwards 
and  forwards  ;  the  perpendicular  direction  of 
the  foramen  ovale  is  changed  more  to  a  hori- 
zontal one,  and  the  opening  assumes  more  of  a 
triangular  form,  its  base  being  turned  towards 
the  acetabulum.  In  consequence  of  the 
changed  situation  of  the  bones  of  the  pelvis,  its 
different  diameters  undergo  an  essential  devia- 
tion from  the  natural  state,  the  superior  aper- 
tures of  the  pelvis  are  commonly  somewhat 


oblique,  and  the  pelvis  is  broader  on  the  affected 
side  from  before  backwards.* 

The  muscles  in  advanced  cases  are  in  a  state 
of  atrophy,  of  a  greenish  hue,  and  often  matted 
together;  sometimes  they  form  the  walls  of 
scrofulous  symptomatic  abscesses,  containing  a 
thin  serous  pus  mixed  with  flakes  ;  sometimes 
the  pus  is  inodorous,  of  ordinary  character. 
Usually  the  contents  of  the  abscess  make  their 
way  to  the  skin,  more  rarely  to  the  mucous 
surfaces.  In  more  advanced  cases  these  ab- 
scesses are  found  to  contain  fetid  air  and  puru- 
lent matter  of  a  very  bad  quality ;  in  these 
latter  circumstances  we  discover  either  an  ex- 
ternal or  internal  fistulous  opening ;  the  walls 
of  the  abscesses  have  collapsed,  and  have  been 
converted  into  fistulous  canals  lined  by  false 
membranes  ;  these  have  become,  as  it  were,  the 
excretory  canals,  through  which  the  matter  has 
been  discharged  from  the  interior  of  the  dis- 
eased joint,  and  through  which  sabulous  mat- 
ter, small  hard  pieces  of  bone,  or  pieces  as  large 
as  the  epiphysis  of  the  head  of  the  femur,  as 
elsewhere  noticed,  have  made  their  way.  The 
abscesses  are  found,  on  dissection  of  those  who 
have  died  of  morbus  coxae  strumosa?,  pointing 
or  to  have  opened  in  various  directions. 

We  have  already  stated  that  the  capsular 
ligament  has  been  found  perforated  by  fistulous 
openings,  and  that  in  the  advanced  stage  of  the 
disease  little  or  no  vestige  of  the  capsule  is  left. 
The  abscesses,  therefore,  we  meet  with  on  dis- 
section may  be  considered  as  reservoirs  for  the 
matter  which  proceeds  from  the  carious  bones  ; 
occasionally,  no  doubt,  we  shall  find  around 
the  joint  abscesses  which  have  no  communica- 
tion whatever  with  the  diseased  articulation :  not 
only  in  the  soft  parts  around  the  joint  have  we 
met  with  such  isolated  collections  of  matter, 
but  also  in  the  body  of  the  os  ilii,  and  in  the 
centre  of  the  trochanter  major  of  the  femur. 

We  have  given  an  account  of  an  acute  case 
of  morbus  coxae,  in  which  a  psoas  abscess  was 
found  to  have  originated  in  a  carious  hip-joint. 
The  communication  of  the  carious  bones  with 
the  interior  of  the  sheath  of  the  psoas  took 
place  through  a  small  perforation  in  the  hori- 
zontal ramus  of  the  os  innominatum.  In  this 
case  also  an  abscess  existed  in  the  true  pelvis, 
and  death  was  the  consequence  of  it,  having 
burst  into  the  vena  cava.  In  Mr.  Liston's 
collection  there  is  a  specimen  shewing  ex- 
tensive destruction  of  the  acetabulum,  head 
and  neck  of  the  femur,  with  several  sinuses 
leading  from  the  joint,  and  one  in  particular 
of  large  size,  leading  towards  the  rectum 
through  the  foramen  ovale ;  there  is  also  the 
rectum  corresponding  to  this  preparation,  with 
a  rounded  opening  sufficient  to  admit  the  point 
of  the  little  finger,  about  an  inch  and  a  half 
above  the  anus.  In  this  case  the  abscess  lay 
across  the  pelvis;  by  one  of  its  extremities  it 
communicated  with  the  diseased  hip-joint 
through  the  foramen  ovale  and  ulcerated  cap- 
sular ligament,  and  by  its  posterior  extremity 
with  the  rectum.  The  case  of  pelvic  abscess 
I  have  so  often  adverted  to  was  very  similarly 

*  Coulson,  p.  42. 


798 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


situated,  but  instead  of  opening  by  its  posterior 
extremity  into  the  rectum,  its  fundus  was  ele- 
vated somewhat  higher  in  the  pelvis,  and  burst 
into  the  vena  cava.  The  late  Dr.  M'Dowel,  in  the 
fourth  volume  of  the  Dublin  Journal,  says  that 
in  two  cases  of  hip-joint  disease  he  had  seen 
several  years  since,  the  matter  had  passed  into 
the  pelvis  through  the  bottom  of  the  acetabu- 
lum, and  there  accumulated  in  such  quantity 
as  to  compress  the  bladder  and  cause  retention 
of  urine,  requiring  the  daily  use  of  the  catheter. 
He  also  adds,  that  this  route  for  the  matter  is 
not  uncommon,  and  in  its  progress  that  it  may 
form  a  tumour  of  considerable  size  by  the  side 
of  the  rectum,  and  occasionally  burst  into  the 
cavity  of  this  intestine.  Sir  A.  Cooper  men- 
tions the  latter  occurrence  in  one  instance.  Dr. 
M'Dowel  adds,  I  had  an  opportunity  of  wit- 
nessing it.  Abscesses  take  their  course  from 
the  diseased  joint  into  the  pelvis,  and  open  into 
the  vagina.  Sir  B.  Brodie  mentions  a  case  of 
this  kind  in  a  child  aged  11  years;  and  in 
Dr.  Kirby's  collection,  which  he  presented 
to  the  College  of  Surgeons,  is  a  similar  ex- 
ample. Dr.  M'Dowel,  in  the  paper  already 
alluded  to,  observes  that  he  is  not  aware  of  its 
being  recorded  that  an  iliac  abscess  may  result 
from  a  caries  of  the  hip-joint,  yet  in  four  cases, 
he  adds,  I  have  found  it  to  occur.  The  fluid 
escaping  through  an  opening  on  the  inside  of 
the  capsular  ligament,  passes  upwards  behind 
the  psoas  and  ascends  into  the  iliac  fossa,  de- 
taching the  muscles  from  the  bone.  In  such 
cases  we  have  considerable  fulness  in  the  groin, 
which  can  be  traced  upwards  behind  Poupart's 
ligament ;  from  the  stretching  of  the  filaments 
of  the  anterior  crural  nerve  more  neuralgic  pain 
attends  this  case  than  we  usually  find  in  disease 
of  the  hip-joint.  The  iliac  vessels  are  dis- 
placed, become  flattened  and  adherent  to  the 
sac ;  from  the  compression  of  the  vein  much 
more  oedema  of  the  limb  is  present  than  in  or- 
dinary eases.  The  ccecum  or  the  sigmoid  flex- 
ure of  the  colon  may  be  considerably  displaced 
or  united  to  the  sac*  Sometimes  it  passes 
behind  the  vessels,  and  accumulating,  it  may 
compress  the  bladder  and  rectum,  which  then 
form  the  inner  wall  of  the  abscess. 

In  a  very  interesting  case  of  iliac  abscess 
which  was  treated  in  the  year  1833  in  the  Rich- 
mond Hospital,  ulceration  of  a  portion  of  the 
ilium  adhering  to  the  wall  of  the  abscess  oc- 
curred, and  its  contents,  after  being  poured  into 
the  abscess,  escaped  externally  through  a  fistu- 
lous opening  near  the  spine  of  the  ilium  ;  ulce- 
ration also  of  the  external  iliac  artery  took  place 
about  an  inch  and  a  half  above  Poupart's  liga- 
ment, and  sudden  death  resulted  from  the 
blood  escaping  in  large  quantity  into  the  cavity 
of  the  abscess.  The  preparation  is  preserved 
in  the  museum  of  the  Richmond  Hospital. 
The  anterior  and  crural  nerves  are  often  found 
on  the  stretch.  We  have  already  mentioned  a 
case  of  this  kind,  (Clarke,)  and  Sir  B.  Brodie 
mentions  one  in  which  he  found  two  enlarged 

*  The  matter,  which  is  generally  prevented  from 
passing  down  into  the  true  pelvis  by  the  connexion 
of  the  fascia  iliaca,  sometimes  makes  its  way  into 
this  cavity  by  ulceration  of  this  fascia. 


lymphatic  glands,  each  the  size  of  a  walnut, 
immediately  below  the  crural  arch  in  the  fore 
part  of  the  joint,  and  these  lay  in  contact  with 
and  immediately  behind  two  branches  of  the 
nerves,  so  as  to  keep  the  latter  on  the  stretch,  like 
the  strings  passing  over  the  bridge  of  a  violin. 

We  must  not  forget  that  the  diseased  action 
in  these  cases  of  chronic  strumous  arthritis  is 
not  confined  to  the  joint.  We  have  seen  ex- 
amples in  the  living  and  specimens  in  mu- 
seums, proving  that  at  the  same  lime  both  hip- 
joints  may  be  engaged  in  the  same  individual. 
In  acute  cases  we  have  given  an  example  of  the 
membranes  of  the  brain  having  been  affected, 
so  also  in  chronic  cases;  tubercles  have  also 
been  found  in  the  lungs,  the  mesenteric  glands 
extensively  enlarged,  and  ulcers  in  the  intes- 
tines, and  tubercular  accretions  in  the  perito- 
neum. 

3.  Chronic  rheumatism. —  (Morbus  coxce 
senilis,  or  chronic  rheumatic  arthritis  of  the 
hip.)  By  these  terms  we  would  wish  to  de- 
signate a  very  peculiar  disease  of  the  hip- 
joint,  the  morbid  results  of  which  are  now  pretty 
well  known  to  pathological  anatomists  ;  but  it 
must  be  confessed  that  very  little  has  been 
done  to  make  the  profession  acquainted  with 
its  symptoms  or  appropriate  treatment. 

History  of  the  disease. — We  will  venture  to 
assert  that  there  cannot  be  a  more  graphic  il- 
lustration given  of  this  disease  and  its  conse- 
quences than  those  to  be  found  in  the  Museum 
Anatomicum  of  Sandifort,  who  has  not  confined 
his  delineations  to  the  head  and  neck  of  the 
thigh-bone,  but  has  also  shewn  the  various 
alterations  of  form  which  the  acetabulum  un- 
dergoes.* For  many  years  this  disease  has 
been  accurately  described  in  the  clinical  lec- 
tures delivered  in  the  different  hospitals  in 
Dublin,  and  the  importance  of  distinguishing 
it  from  the  other  affections  of  this  articulation 
has  been  pointed  out.  Mr.  Benjamin  Bell,  in 
his  work  on  the  bones,  has,  under  the  head  of 
"  interstitial  absorption  of  the  neck  of  the 
thigh-bone,"  alluded  to  this  disease,and  detailed 
many  of  its  external  signs,  as  well  as  the  mor- 
bid changes  which  the  neck  of  the  bone  suffers  ; 
and  in  the  sixth  volume  of  the  Dublin  Journal, 
Mr.  Smith,  in  a  paper  on  the  diagnosis  of  in- 
juries of  the  hip,  has  given  a  very  good  and 
concise  account  of  this  remarkable  affection  of 
the  hip-joint. 

The  writer  of  this  article  long  ago,  in  his 
lectures,  gave  the  name  of  morbus  coxa  seni- 
lis to  the  disease  in  question,  but  as  he  has 
since  met  with  many  instances  of  it  occurring 
so  early  as  at  the  age  of  thirty  or  forty,  he  is 
now  disposed  to  substitute  for  this  name  that  of 
chronic  rheumatic  arthritis  of  the  hip-joint, 
and  he  considers  it  as  the  same  disease  pre- 
cisely as  he  has  elsewhere  in  this  work  described 
as  affecting  other  articulations.  (See  Elbow, 
Hand,  Knee,  Shoulder.) 

As  to  the  cause  of  this  chronic  disease  of  the 
hip-joint,  we  believe  little  is  known.  We 
have  heard  it  frequently  attributed  to  the  effects 
of  cold  and  wet ;  and  an  acute  attack  of  rheu- 

*  Mus  Anatom.  Lugduui  Batavorum,  1793. 
vol.  ii.  tab.  lxix.  ad  lxxiii. 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


799 


matic  arthritis  of  the  hip-joint  produced  by 
cold,  we  can  easily  conceive  may  occasionally 
merge  into  the  chronic  affection  we  wish  to 
describe.  We  have  also  reason  to  think  that 
falls  upon  the  great  trochanter  have  given  rise 
to  the  first  symptoms  of  this  disease ;  but  in 
many  cases  no  satisfactory  cause  can  be  assigned 
by  the  patient  for  the  origin  of  the  affection. 

Symptoms,  4'C- — The  patient  complains  of 
stiffness  in  the  hip-joint  and  about  the  great 
trochanter;  also  of  a  dull  boring  pain  which 
extends  down  the  front  of  the  thigh  to  the 
knee.    The  stiffness  is  most  felt  in  the  morning 
when  the   patient  commences  to  walk  ;  but 
after  exercise  the  movements  of  the  joint  be- 
come somewhat  more  free.    In  the  evening 
of  a  day  the  patient  has  had  much  walking 
exercise,  the  pain  is  always  more  severe.  The 
uneasiness,  however,  gradually  subsides  after 
he  has  retired  to  bed.    The  pain  is  always  in- 
creased when  the  patient  throws  the  weight 
of  his  body  fully  on  the  affected  joint.  But 
let  the  surgeon  press  on  the  great  trochanter, 
or  adopt  any  other  expedient  so  as  to  push  the 
head  of  the  bone  even  rudely  against  the  ace- 
tabulum, and  these  manoeuvres  are  the  sources 
of  no  uneasiness  whatever  to  the  patient.  Al- 
though we  can  easily  satisfy  ourselves  that  no 
actual  anchylosis   exists,  still   it  is  evident 
enough  that  the  motion  of  rotation  is  lost,  and 
that  the  other  movements,  particularly  flexion, 
are  confined  within  very  narrow  limits.  When 
we  place  the  patient  in  a  horizontal  position, 
and  endeavour  to  communicate  any  of  these 
movements  to  the  hip-joint,  the  patient  com- 
plains of  pain,  and  an  evident  crepitation  can  be 
heard  and  felt  deep  in  the  articulation.  The  limb 
is  apparently  shortened  by  from  two  to  three 
inches  ;  the  apparent  shortening  arises  from  the 
obliquity  of  position  of  the  pelvis  relatively  to  the 
spine,  and  the  elevation  of  the  affected  side  is 
such  that  the  crest  of  the  ilium  and  the  last  short 
rib  approach  nearer  to  each  other  at  this  side 
in  the  ordinary  attitude  of  standing  by  two 
inches  than  those  of  the  opposite  side.  All 
these  circumstances  account  for  the  apparent 
shortening  of  the  limb,  which  however,  on 
accurate  measurement,  will  be  found  not  to  be 
really  shortened  more  than  an  inch.  The  patient 
walks  very  lame,  and  with  the  foot  and  whole 
limb  greatly  everted.    The  nates  of  the  sound 
side  is  unusually  prominent,  while  that  of  the 
affected  side  is  quite  flat,  and  no  trace  of  the 
lower  fold  of  the  glutauis  is  seen.    The  mus- 
cles of  the  thigh  also  seem  somewhat  atrophied, 
still  they  do  not  want  for  firmness ;  and  we 
may  uniformly  observe  that  the  calf  of  the  leg 
of  the  affected  limb  is  not  inferior  in  size  and 
firmness  to  the  other.    When  we  minutely 
examine  the  great  trochanter,  we  find  it  larger 
and  more  prominent  than  usual ;  and  about  the 
situation  of  the  acetabulum,  horizontal  branch 
of  the  os  pubis,  and  lesser  trochanter,  bony  pro- 
tuberances can,  upon  careful  examination,  be 
recognized.  This  disease,  when  once  fully  esta- 
blished in  the  hip-joint,  rarely  or  never  extends 
itself  to  the  other  articulations.     We  have 
known,  however,  a  few  examples  in  which  it 
affected  both  hip-joints  in  the  same  individual. 


The  chronic  inflammation  of  the  various  struc- 
tures of  the  joint  in  which  the  disease  consists, 
is  never  accompanied  by  any  appreciable  de- 
gree of  heat  or  external  swelling  of  the  soft 
parts,  and  we  have  never  heard  of  the  inflam- 
mation going  on  to  suppuration. 

The  following  case  will  shew  the  necessity 
of  making  the  profession  fully  acquainted  with 
this  disease,  as  it  proves  how  very  obscure  are 
the  early  signs  of  the  affection,  and  that  even 
the  morbid  appearances  may  be  confounded 
with  those  which  are  the  result  of  accident. 
At  the  meeting  of  the  British  Association  in 
Dublin,  in  the  year  1836,  one  of  its  most  dis- 
tinguished members,  Mr.  Snow  Harris  of  Ply- 
mouth, made  the  following  communication  to 
the  medical  section  : — "  Sir  A.  Cooper  and 
many  other  eminent  surgeons  had  doubted  the 
possibility  of  union  taking  place  in  fracture  of 
the  neck  of  the  thigh-bone,  within  the  capsular 
ligament.  A  case  had  lately  fallen  under  his 
(Mr.  H.'s)  notice,  which  he  thought  would 
tend  to  set  the  question  at  rest.  It  was  that  of 
a  gentleman  who  had  received  an  injury  by 
being  thrown  from  his  gig  ten  years  ago.  He 
had  got  up  and  walked  immediately  after  the 
accident,  but  continued  lame  from  that  period 
up  to  the  time  of  his  death.  He  had  been  at- 
tended by  some  of  the  most  celebrated  surgeons 
in  London,  but  they  had  not  been  able  to  de- 
termine whether  there  was  a  fracture  of  the 
bone  or  not,  but  kept  him  lying  on  a  sofa  for 
nearly  twelve  months.  The  injured  limb  was 
shortened,  the  foot  everted,  the  thigh  wasted, 
and  owing  to  the  constant  inclination  of  the 
body  forward  on  one  side,  a  lateral  curvature 
of  the  spine  took  place.  Some  time  ago  the 
gentleman  died  of  disease  of  the  heart;  and 
Mr.  Harris,  being  anxious  to  examine  the 
parts,  removed  the  acetabulum  and  a  portion  of 
the  thigh-bone,  which  he  then  presented  for 
the  inspection  of  the  meeting.  He  had  found 
the  trochanter  higher  up  than  natural,  and  the 
neck  of  the  bone  shortened  ;  a  section  of  the 
bone  had  been  made,  and  the  line  of  union,  in 
Mr.  Harris's  opinion,  was  clearly  manifest."  * 

When  Mr.  Harris  exhibited  this  specimen  to 
the  medical  section  of  the  British  Association 
which  met  in  Dublin,  it  excited  much  interest, 
first  as  the  individual,  the  subject  of  the  case, 
was  the  celebrated  comedian  Mr.  Matthews, 
and  secondly,  as  at  the  announcement  of  the  case 
it  was  asserted  that  it  settled  in  the  affirmative 
the  much  agitated  question,  whether  the  intra- 
capsular fracture  of  the  cervix  femoris  was  or 
was  not  susceptible  of  osseous  union.  The 
writer  was  present  at  the  communication  of  this 
case  to  the  section,  and  upon  the  presentation 
of  the  specimen  expressed  his  doubts  that  this 
case,  either  from  its  history  or  post-mortem 
appearances,  was  an  example  of  the  intra-cap- 
sular  fracture,  and  rather  held  the  opinion  that 
it  was  one  of  this  chronic  rheumatic  affection 
which  he  has  been  endeavouring  to  describe ; 
in  which  opinion  he  was  most  decidedly  con- 
finned  upon  inspecting  the  acetabulum,  the 
widening  of  this  cavity,  the  complete  filling  up 

*  Sec  Dublin  Journal,  vol.  viii. 


800 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


of  the  fossa  which  is  normally  destined  to  con- 
tain the  substance  called  Haversian  gland,  the 
shortening  of  the  neck  of  the  femur  and  depres- 
sion of  the  head  towards  the  lesser  trochanter, 
and  the  ivory  deposition  on  it.  In  this  view  Mr. 
Smith,  who  had  so  well  described  the  disease  in 
question,  and  the  hospital  surgeons  around  him, 
concurred,  and  Mr.  Snow  Harris  himself  quickly 
became  a  convert  to  our  views,  and  we  are  sa- 
tisfied from  what  we  observed  of  his  liberality, 
that  we  have  his  full  permission  to  communicate 
this  case  in  its  present  form  to  the  profession. 
The  sketch  (fig.  315)  is  taken  from  the  cast  of  the 


Fig.  315. 


Mr.  Snow  Harris's  case. 


head  and  neck  of  the  femur  presented  by  Mr. 
Harris  to  the  College  of  Surgeons,  Dublin.  The 
upper  part  of  the  head  of  the  femur  was  exceed- 
ingly rough  on  its  surface,  and  of  an  oval  form 
from  above  downwards ;  the  axis  of  the  neck 
was  at  right  angles  with  the  shaft,  and  seemed 
lo  run  horizontally  inwards  and  backwards,  so 
that  the  length  of  the  fossa  which  exists  poste- 
riorly between  the  corona  of  the  head  and  the 
posterior  inter-trochanteric  line,  was  in  this  case 
less  than  a  quarter  of  an  inch,  a  fossa  which 
we  know  naturally  measures  two  inches.  In 
viewing  the  oval  form  of  the  head,  we  conclude 
the  movement  of  rotation  must  have  been  im- 
possible ;  from  the  shortening  of  the  neck  pos- 
teriorly, we  can  infer  that  the  toe  and  foot  must 
have  been  greatly  everted,  and  from  the  depres- 
sion of  the  head,  to  the  level  of  the  trochanter, 
the  femur  must  have  been  nearly  one  inch 
shorter  than  the  other.  The  lamented  indivi- 
dual had  not  suffered  from  the  disease  more 
than  ten  years,  so  that  the  morbid  appearances 
were  not  to  the  same  amount  as  we  are  accus- 
tomed to  see  as  the  result  of  this  very  slow  dis- 
ease. 

The  following  case  is  that  of  an  individual 
who  has  been,  to  the  writer's  knowledge,  suffer- 
ing for  many  years  under  this  disease. 

Patrick  Macken,  now-  aged  seventy-seven 
years,  was  brought  up  as  a  postilion  and  groom, 
but  for  the  last  seventeen  years  has  been  quite 
unfit  for  service  in  consequence  of  his  having 
been  afflicted  with  a  very  severe  pain  in  his 
right  hip  ;  from  the  first  attack  of  which  he  be- 
came lame,  and  ever  since  the  lameness  has 
been  slowly  but  gradually  increasing.  In  every 


Fig.  316. 


Chronic  rheumatic  arthritis  of  tlie  Hip. 


other  respect  his  health  is  excellent,  except  that 
he  has  some  wandering  rheumatic  pains  in  other 
joints,  particularly  in  the  right  shoulder. 

Hewalkswith  great  labour  and  pain,  and  now 
requires  the  assistance  of  a  stick  in  each  hand  (Jig. 
316);  in  the  morning  his  movements  are  stiff  and 
confined,  but  they  become  freer  on  exercise;  in 
the  evening  of  a  day  he  has  walked  much,  the  pain 
and  stiffness  are  worse  and  increased  in  propor- 
tion to  the  excess  of  exercise  and  labour  he  had 
undergone  in  the  day.  While  he  remains  in  bed 
he  rests  on  the  affected  hip,  and  suffers  no  pain 
whatever  except  he  suddenly  turns  himself  in- 
cautiously. As  soon  as  he  gets  up  and  throws  his 
entire  weight  on  the  diseased  hip-joint,  the  pain 
commences;  if  asked  in  what  particular  part  of 
the  joint  he  feels  most  suffering,  he  points  to  the 
back  part  of  the  great  trochanter  and  to  a  point 
which  corresponds  to  the  situation  of  the  lesser 
trochanter ;  he  says  the  pain  shoots  from  these 
points  down  the  front  of  the  thigh  to  the  knee. 
These  pains  are  sometimes  more  severe,  and 
sometimes  less,  without  his  being  able  to  as- 
sign any  cause  for  these  alterations,  and  he  can- 
not observe  that  the  state  of  the  weather  has  any 
influence  on  them  whatever. 

As  he  stands  at  rest,  he  throws  the  weight 
of  his  body  on  the  left  or  unaffected  limb, 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


801 


while  the  right  leg  hangs  in  front  and  slightly 
across  the  left,  and  seems  to  be  at  least  three 
inches  shorter;  he  leans  slightly  back  and 
supports  himself  on  two  sticks :  as  he  walks 
the  right  foot  is  considerably  everted,  and  when 
he  moves  without  sticks  (which  he  accomplishes 
with  the  greatest  difficulty)  he  places  the  whole 
sole  of  the  foot  flat  upon  the  ground.  He 
never,  however,  ventures  of  his  own  accord  to 
move  without  the  help  of  two  sticks,  by  the  assist- 
ance of  which  he  is  enabled  to  walk  quicker; 
while  moving  along  thus,  the  heel  of  the 
affected  limb  does  not  quite  reach  the  ground, 
and  the  lumbar  vertebrae  undergo  great  motion. 
He  cannot  under  any  circumstances  flex  the 
thigh  on  the  abdomen,  so  that  when  he  assumes 
the  sitting  posture,  he  is  obliged  to  place  him- 
self forwards  on  the  very  edge  of  the  seat,  the 
right  thigh  remaining  in  the  same  line  as  the 
axis  of  the  trunk,  the  leg  usually  flexed  and 
placed  under  the  chair,  or  across  behind  the 
other,  and  he  finds  the  utmost  difficulty  in 
putting  on  his  stockings  and  shoes.  He  has 
scarcely  any  motion  in  the  hip-joint.  When 
we  view  the  hip  in  front,  and  examine  it,  we 
see  and  can  feel  a  considerable  bony  fulness, 
corresponding  to  the  horizontal  branch  of  the 
pubis :  the  trochanter  major  seems  placed  very 
high  up,  and  is  extraordinarily  large  as  if  sur- 
rounded with  ossific  deposits.  The  thigh  is 
somewhat  atrophied,  being  an  inch  and  a  half 
less  in  circumference  than  the  other,  but  the 
calf  of  the  leg  is  not  reduced,  and  the  muscles 
seem  firm  ;  the  apparent  shortening  of  the  limb, 
when  he  rests  on  the  sound  one,  arises  from  the 
lumbar  vertebra  being  much  curved  to  the  oppo- 
site side,  and  the  pelvis  being  elevated  on  the 
affected  side,  while  the  real  shortening  ascer- 
tained by  accurate  measurement  amounts  only 
to  half  an  inch. 

If  we  place  the  patient  horizontally  and 
attempt  to  communicate  to  the  hip-joint  any 
movement,  as  of  rotation,  flexion,  abduction,  a 
well-marked  crepitus  is  elicited,  and  the  range 
of  motion  is  found  to  be  very  limited  indeed; 
a  little  abduction  is  admitted ;  rotation  and 
flexion  seem  just  to  a  sufficient  degree  to 
shew  that  no  anchylosis  exists.  The  move- 
ments give  some  pain  to  the  patient,  but  we 
can  press  the  trochanter  firmly  so  as  to  direct 
the  head  of  the  bone  deep  against  the  fundus 
of  the  acetabulum,  and  we  can  even  strike  the 
heel  and  sole  of  the  foot  with  violence  without 
giving  the  patient  the  slightest  sensation  of  pain. 

The  anatomical  characters  of  this  disease 
are  very  well  marked.  The  muscles  are  usually 
of  a  paler  colour  than  natural,  and  are  found 
not  to  be  so  well  developed  ' as  those  of  the 
opposite  or  sound  hip.  The  fibrous  capsule 
of  the  joint  is  greatly  thickened,  the  cotyloid 
ligament  is  either  ossified  or  absorbed,  and 
the  ligament  which  completes  the  notch,  and 
in  the  natural  state  gives  origin  to  the  liga- 
mentum  teres,  is  usually  converted  into  bone, 
leaving  generally  beneath  its  arch  whether 
bony  or  not  a  space  for  the  transmission  of 
bloodvessels  to  the  interior  of  the  joint;*  when 

*  Cruveilhicr,  livraison  iv.  p.  L  La  presence 
VOL.  II. 


the  disease  is  fully  established  the  ligamentum 
teres  is  altogether  removed,  the  synovial  fluid 
is  deficient  in  quantity,  and  the  cartilage  is 
removed  from  the  bottom  of  the  acetabulum, 
and  upper  surface  of  the  head  of  the  femur.  If 
here  and  there  some  vestige  of  the  synovial 
membrane  or  sub-synovial  tissue  remain,  it  is 
in  a  highly  vascular  condition,  presenting  an 
intensely  red  colour.  In  a  case  of  dissection 
which  Messrs.  Smith,  Brabazon,  and  the  writer 
witnessed  lately  of  this  disease,  we  observed 
that  the  shortened  neck  of  the  femur  was 
entirely  surrounded  with  a  number  of  red 
villous  -  looking  productions  of  the  synovial 
membrane.  These  were  of  a  rounded  and 
conical  form,  half,  an  inch  long  and  two  or 
three  lines  broad  at  their  bases.  They  resem- 
bled much  in  form  the  long  conical  papillae  to 
be  seen  on  the  tongue  and  about  the  fauces 
of  herbivorous  quadrupeds  ;  however,  instead 
of  being  white  and  firm  they  were  soft  and 
villous,  and  of  an  intensely  red  colour.  The 
line  of  the  corona  of  the  head  was  absorbed  and 
excavated  in  points,  and  the  different  foveas  or 
depressions  were  completely  occupied  by  these 
vascular  fimbriae.  Still  more  recently  the  wri- 
ter met  with  a  similar  specimen  which  he  pre- 
sented for  inspection  to  the  Pathological  So- 
ciety, in  which  these  vascular  fimbriae  were 
equally  conspicuous.* 

The  acetabulum  is  generally  much  larger 
and  deeper  than  natural,  and  forms  a  circular 
cup  often  two  inches  deep  with  a  complete  level 
brim,  which  is  sometimes  so  much  narrowed  as 
to  render  the  extraction  of  the  head  of  the 
femurdifficult.  This  is  the  most  frequent  abnor- 
mal appearance  the  acetabulum  presents ;  but 
occasionally  it  is  increased  in  size,  and  is  at  the 
same  time  very  shallow  and  of  an  oval  form. 

When  we  examine  the  bottom  of  the  acetabu- 
lum we  find  it  widened  and  not  any  trace  of 
Haversian  gland  is  left ;  the  interior  presents  a 
worn  and  porous  appearance,  the  cartilage  and 
compact  stratum  of  bone  which  the  caitilage 
normally  covers,  having  been  removed,  and  in 
some  places  where  the  friction  and  pressure 
from  the  head  of  the  femur  have  been  greatest, 
instead  of  a  rough  and  worn  porous  appearance, 
resulting  from  the  exposure  of  the  cells  of  the 
bone,  a  dense  enamel  has  been  as  it  were 
ground  into  these  pores,  and  here  the  surface 
presents  the  polish,  smoothness,  and  hardness 
of  ivory.  This  mechanical  removal  of  the  carti- 
lage and  exposure  of  the  interior  of  the  cells  of 
the  bone,  and  substitution  for  the  cartilage  of 
a  dense  inanimate  enamel,  we  imagine,  are  pro- 
cesses which  are  not  confined  to  the  acetabu- 
lum ;  but  their  results  are  seen  also  on  those 
parts  of  the  head  of  the  femur  which  are  sub- 
jected to  pressure  and  friction  ;  hence  we  find 
the  effects  of  friction,  above  alluded  to,  most 

d'un  nerf et  d'un  vaisseau,  cespartiesfondamentales 
de  l'organisation,  semblent  en  quclque  sorte  re- 
spectees  par  les  lesions  organiqucs,  qu'elles  soient 
ces  lesions  circulent  tout  a  lit  our,  mais  ne  les  en- 
vahissent  presque  jamais,  oil  du  moins  les  envahis- 
sent  apres  tous  les  autres  tissues  lorsquellcs  sont 
parvenus  a  leur  dernie.re  periode. 

*  Dublin  Journal  for  March  1839,  No.  xliii. 

3  G 


802 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


upon  the  upper  surface  of  its  head  which 
supports  the  acetabulum  in  standing  and  pro- 
gression. The  form  of  the  head  of  the  bone 
becomes  changed  and  flattened  from  above 
downwards  ;  something  like  a  bending  or 
yielding  of  the  neck  of  the  bone  may  now 
be  observed,  and  sometimes  the  inferior  part  of 
the  circumference  of  the  head  of  the  femur  is  so 
mucl)  depressed  that  the  under  surface  of  the 
head  has  approached  to  the  lesser  trochanter. 


Fig.  317. 


Upon  a  cursory  examination,  it  looks  as  if  the 
"  head  of  the  bone  were  forced  downwards  by 
the  action  of  some  great  pressure  from  above, 
and  cases  have  occurred  in  which  at  last  the 
head  of  the  femur  seemed  to  have  sunk  even 
below  the  level  of  the  great  trochanter,  and  to 
be  supported  by  the  lesser."    ( B.  Bell.) 

But  besides  these  which  we  attribute  to  the 
effects  of  physical  causes,  there  is,  in  the  con- 
templation of  the  morbid  results  of  this  chronic 
disease  of  the  hip-joint,  sufficient  to  satisfy  us 
that  a  very  active  vital  process  is  going  on  in 
the  interior  of  the  bones,  as  well  as  in  all  the 
structures  around  the  diseased  joint.  The 
Ihickening  of  the  fibrous  capsule,  and  hyper- 
amic  state  of  the  synovial  structures,  the  exu- 
berant growth  of  bone  which  we  see  around 
deepening  the  acetabulum,  or  surrounding  its 
brim  with  bony  nodules;  the  enlargement  of 
the  head  of  the  femur,  so  as  to  make  this  head 
assume  an  oval  convex  surface,  measuring  in 
circumference  ten  inches  and  a  half,  as  in  the 
specimen  from  which  the  drawing  (Jig.  317)  was 
taken,  all  these  are  sufficient  proofs  that  besides 
the  inlerstitial  absorption  going  on  in  the  interior 
of  the  cervix  femoris  in  these  cases,  a  very 
active  condition  of  the  minute  arteries  exists 
externally,  giving  birth  to  those  exostotic 
deposits  which  encircle  the  head  and  inter- 
trochanteric lines  of  the  femur.  It  has  been 
remarked,  and  we  think  with  much  truth,  that 
those  specimens  which  have  been  frequently 
produced  and  mistaken  for  united  fracture  of 
the  neck  of  the  femur,  have  been  examples  of 
interstitial  absorption  of  the  neck  of  this  bone 
combined  with  external  exostotic  deposits;  but 
these  mistakes,  however,  we  trust  are  not  here- 
after likely  to  occur. 

Section  111.  Accident. — The  hip-joint  is, 
of  course,  like  the  other  articulations,  liable  to 


sprains  and  to  contusions.  These  do  not  re- 
quire any  special  notice  here;  but  fractures 
and  luxations  of  the  bones  of  this  important 
articulation  demand  from  us  full  consideration. 

I.  Fractures. — Fractures  of  the  os  innomi- 
natum  may  traverse  the  bottom  or  fundus  of 
the  acetabulum,  or  some  portion  of  the  brim 
of  this  articular  cavity  may  have  been  broken 
off. 

1.  Fracture  of  the  acetabulum.  A.  Fracture 
of  its  fundus. — When  fracture  of  the  bones  of 
the  pelvis  happens  to  traverse  the  bottom  of  the 
acetabulum,  the  prognosis  is  unfavourable,  as  it 
is  in  all  cases  of  fracture  of  the  bones  of  the  pelvis. 
When  this  fracture  through  the  fundus  of  the 
acetabulum  is  the  consequence  of  a  fall  on  the 
feet,  knees,  or  trochanter  major  of  the  femur,  it 
sometimes  happens  that  the  head  and  neck  of 
the  femur  unbroken  are  driven  into  the 
cavity  of  the  pelvis.  "  Nous  avons  observe," 
says  Dupuytren,  "  plusieurs  fois,  l'enfonce- 
ment  de  la  cavite  cotyloide  par  la  pression 
exercee  par  la  tete  du  femur,  a  la  suite  d'une 
chute  surle  pied  ou  lesgenoux."  In  this  case, 
the  head  of  the  femur  is  driven  with  force 
against  the  fundus  of  the  acetabulum,  and  the 
latter  breaks,  and  is  crushed  in,  "  enfonce."  The 
most  remarkable  case  observed  by  Dupuytren 
was  the  following : — "  The  bottom  of  the  cotyloid 
cavity  had  been  driven  in,  and  the  head  of  the 
femur  had  passed  entirely  into  the  pelvis.  The 
neck,  which  had  not  suffered  any  solution  of 
continuity,  was  so  strongly  engaged  in  the 
opening,  that,  even  when  making  the  anatomi- 
cal examination,  I  found  it  very  difficult  to 
disengage  it,  and  to  reduce  this  new  species  of 
luxation."*  As  these  important  remarks  of 
Dupuytren  are  not  accompanied  by  all  the 
detail  that  is  to  be  desired,  where  novel  obser- 
vations are  reported,  we  shall  here  adduce  the 
following  case  of  fracture  of  the  fundus  of  the 
acetabulum,  with  displacement  of  the  head  of 
the  femur  into  the  pelvis.  Death  occurred  on 
the  fortieth  day  after  the  injury,  from  diffuse 
inflammation.  An  opportunity  was  afforded  to 
us  of  investigating  anatomically  the  precise  na- 
ture of  the  lesions  in  this  case. 

On  the  3rd  of  December,  1834,  a  man, 
named  William  Sherlock,  set.  26,  a  painter  by 
trade,  was  admitted  into  Jervis-street  Hospital, 
under  the  care  of  the  late  Mr.  Wallace.  A 
few  minutes  before  his  admission,  this  poor 
man  had  fallen  from  a  ladder,  from  a  height 
reported  to  be  fifty  feet,  on  the  flags  of  the 
street.  On  the  next  day,  the  4th  of  December, 
when  he  had  recovered  from  the  insensibility 
and  collapse  which  had  succeeded  to  the  fall, 
we  found  him  complaining  of  intense  pain  of 
the  right  hip.  He  was  quite  unable  to  move 
the  right  thigh,  and  would  not  permit  any  exa- 
mination of  the  hip,  as  the  slightest  movement 
communicated  to  the  limb  produced  intense 
agony.  The  integuments  covering  the  tro- 
chanter were  discoloured,  and  there  was  much 
swelling  around  the  hip-joint.  The  right  or 
injured  extremity  was  two  inches  shorter  than 
the  left,  which  circumstance  he  attributed  to  a 

*  Lemons  Orales. 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


803 


fracture  of  the  femur,  which  had  occurred  some 
years  previously-  Besides  this  severe  injury  of 
the  hip,  it  was  also  manifest,  from  some 
dyspnoea,  cough,  and  bloody  expectoration,  that 
his  chest  was  also  injured,  but  venesection  and 
other  suitable  treatment  having  been  resorted 
to,  the  affection  of  the  chest  seemed  to  subside. 
His  cough  and  dyspnoea  for  a  time  had  disap- 
peared, and  his  pulse  fell  to  80.  On  the  twenty- 
third  day  from  the  accident,  he  said  he  felt  that 
he  had  caught  a  most  severeand  violent  cold,  from 
a  window  having  been  kept  open  over  his  head. 
On  this  (23rd)  morning,  I  found  him  suffering 
from  great  difficulty  of  breathing  and  violent 
fits  of  coughing,  accompanied  by  scanty  frothy 
expectoration.  His  pulse  was  110,  and  hard, 
his  tongue  was  brown  and  dry,  his  skin  was  hot, 
and  I  learned  that  these  symptoms  had  suc- 
ceeded to  a  rigor.  They  were  attributed  by  me 
to  pneumonia  with  acute  pleuritis  and  consi- 
derable effusion,  of  which  there  were  found,  on 
examination  of  the  chest  by  auscultation  and 
percussion,  very  evident  signs.  These  were 
actively  combated  by  the  ordinary  treatment, 
but  without  success.  His  pulse  was  generally 
120.  He  had  cough,  with  muco-purulent  ex- 
pectoration, and  dyspnoea.  He  slill  obstinately 
refused  to  permit  any  accurate  examination  of 
the  limb  to  be  made.  He  said  his  right  thigh 
was  now  as  powerless  as  at  first,  but  the  injury 
did  not  prevent  him  sitting  up  in  bed,  when, 
from  the  urgency  of  the  dyspnoea,  he  felt  the 
desire  for  this  position ;  on  one  occasion  he 
had  himself  taken  up,  and  placed  for  a  time 
sitting  up  in  a  chair.  On  the  thirty-third  day 
after  his  admission,  I  found  that  his  right  leg  and 
thigh  had  swollen,  that  he  had  raved  much 
during  the  night;  and  that  he  had  alternate 
flushings  and  paleness  of  countenance,  which 
betrayed  much  distress.  He  now  complained 
of  pain  in  the  right  shoulder.  His  pulse  was 
130,  small  and  compressible.  He  had  reten- 
tion of  urine.  His  temper  was  irritable;  his 
tongue  was  red,  and  morbidly  clean  and  dry. 
He  had  much  thirst.  His  lips  were  pale  and 
bloodless.  He  died  on  the  12th  January,  the 
fortieth  day  from  the  accident. 

Post-mortem  examination. — There  was  effu- 
sion of  pus  into  the  cavity  of  the  right  pleura, 
and  the  usual  results  of  acute  pleuritis  ;  pus 
also  in  the  cavity  of  the  pericardium,  and  a  thin 
reticulated  layer  of  lymph  on  the  surface  of  the 
heart.  An  incision  made  through  the  soft  parts 
to  expose  the  bones  of  the  hip-joint  gave  exit 
to  a  large  quantity  of  dark  brown  serum,  mixed 
with  pus.  This  collection  of  matter  extended 
from  the  superior  part  of  the  thigh,  under  the 
peritoneum  up  to  the  kidney.  The  soft  parts 
having  been  removed,  and  the  bones  exposed, 
it  was  found  that  the  shaft,  head,  and  neck  of 
the  femur  were  uninjured,  but  the  head  of  the 
bone  was  driven  through  the  fundus  of  the 
acetabulum,  which  was  fractured  in  a  stellated 
manner,  having  been  divided  into  three  por- 
tions. The  spiculated  edges  of  the  cavity  pro- 
truded into  the  pelvis  to  the  extent  of  one  inch. 
They  were  sharp  and  hard.  Nature  had  not 
made  the  slightest  attempt  at  reparation.  The 
finger  could  be  passed  along  the  neck  of  the 


thigh-bone  into  the  cavity  of  the  pelvis, 
through  the  perforation  in  the  bottom  of  the 
acetabulum.  The  pelvis  had  been  broken  in 
several  places.  There  was  a  comminuted 
fracture  of  the  horizontal  ramus  of  the  pubis 
near  its  crest.  There  was  another  fracture  of 
this  ramus  at  its  junction  with  the  ilium,  and 
a  fracture  through  the  body  of  the  os  innpmi- 
natum  extended  from  the  anterior  inferior  spi- 
nous process  to  the  great  sciatic  notch. 

B.  Fracture  of  the  brim  of  the  acetabulum. 
■ — -The  superior  and  back  part  of  the  cotyloid 
cavity,  which  overhangs  the  head  of  the  femur, 
which  is  called  by  Soemmering  the  supercilium, 
is  sometimes  broken  off,  and  it  follows  almost 
as  a  necessary  consequence,  that  a  dislocation 
upwards  and  backwards  of  the  head  of  the 
femur  shall  occur.  It  is  an  accident  most  liable 
to  be  mistaken,  and  most  difficult  to  manage. 
We  believe,  indeed,  in  all  the  cases  which  have 
occurred,  that  permanent  lameness  has  been  the 
result.  In  such  cases,  the  luxation  of  the  hip 
is  reduced  without  much  difficulty,  but  dis- 
placement again  shortly  recurs.  In  symptoms 
and  effects  the  case  has  a  strong  resemblance 
to  the  congenital  luxation  of  the  femur.  I  was 
once  invited  by  my  friend,  Mr.  Hilles,  (now  of 
London,)  to  see  a  case  of  supposed  dislocation 
upwards  and  backwards  on  the  dorsum  of  the 
ilium.  I  met  the  late  Dr.  M' Dowel  in  con- 
sultation on  the  case.    It  was  as  follows  : — 

Thomas  Venables,  set.  25,  on  the  4th  of  Oc- 
tober, 1834,  received  a  severe  injury  of  the 
right  hip-joint  in  leaping  across  a  ditch,  having 
alighted  with  force  upon  the  right  leg.  He  fell 
immediately,  and  was  unable  to  rise  from  the 
ground,  or  to  walk  or  stand  when  raised. 
When  the  patient  was  supported  in  the  erect 
posture,  he  had  the  ordinary  symptoms  of  dis- 
location of  the  thigh-bone  upwards  and  back- 
wards on  the  dorsum  of  the  ilium.  No  cre- 
pitus was  discovered.  On  the  following 
morning  an  extending  force  having  been  ap- 
plied by  the  pulleys,  the  head  of  the  bone 
resumed  its  natural  situation,  and  the  deformity 
of  the  limb  disappeared.  When  the  patient 
was  visited  on  the  following  morning,  (the  6th,) 
it  was  found  that  during  the  night  the  head  of 
the  bone  had  started  from  the  acetabulum,  and 
that  all  the  former  signs  of  the  injury  had  re- 
appeared. On  the  7th,  the  displacement  was 
again  reduced.  While  the  bone  was  yielding 
to  the  force  of  the  pulleys,  the  writer  had  the 
palm  of  his  hand  pressing  on  the  great  tro- 
chanter, as  this  last  advanced  slowly  towards 
the  acetabulum.  He  was  sensible  of  a  rough 
grating  sensation,  which  was  communicated  to 
his  hand,  and  gave  him  the  idea  as  if  the  head 
of  the  bone  were  dragged  along  a  scabrous  rough 
surface.  The  case  proceeded  favourably  until 
the  night  of  the  10th,  when,  owing  to  the  dis- 
turbance occasioned  by  the  action  of  a  purga- 
tive medicine,  the  dislocation  recurred  a  third 
time.  It  was  observed  that,  although  when  the 
patient  was  supported  out  of  bed  the  foot  was 
inverted,  still  the  toes  could  be  somewhat 
everted.  An  accurate  examination  being  now 
instituted  to  ascertain  whether  a  fracture  ex- 
isted, a  distinct  crepitus  was  discovered  at  the 

3  c  2 


804 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


upper  and  back  part  of  the  acetabulum.  The 
crepitus  and  frequent  recurrence  of  the  dis- 
placement rendered  it  sufficiently  obvious  that 
the  brim  of  the  acetabulum  had  been  broken 
in  the  above-mentioned  situation.  The  bone 
was  a  third  time  restored  to  its  place,  and  a 
strong  band  placed  around  the  pelvis.  Inl83G, 
I  admitted  the  man  into  the  Richmond  Hos- 
pital. He  was  at  this  time  unable  to  walk 
without  the  assistance  of  a  crutch.  The  in- 
jured limb  was  one  inch  and  a  half  shorter  than 
the  other.  When  standing,  he  rested  it  upon 
the  points  of  the  toes,  the  heel  being  drawn 
upwards;  but  a  slight  degree  of  extension  was 
sufficient  to  restore  it  to  its  natural  length  ;  and 
when  the  man  was  lying  in  bed  there  was 
hardly  any  difference  perceptible  in  the  length 
of  the  two  limbs.  The  breadth  of  the  injured 
hip  was  occasionally  greater  than  that  of  the 
sound  one,  and  the  head  of  the  femur  could  be 
pushed  upwards  easily,  and,  of  course,  it  al- 
ways ascended,  when  the  patient  endeavoured 
to  support  his  weight  upon  it ;  and  in  many 
motions  of  the  joint,  the  rubbing  together  of  the 
broken  surfaces  was  distinctly  audible. 

After  having  remained  in  the  Richmond 
Hospital  under  our  observation  for  two  months, 
lie  was  discharged.  Nothing  could  be  devised 
to  make  his  limb  more  useful  to  him.  The 
fracture,  therefore,  of  the  supercilium  of  the  ace- 
tabulum is  a  very  serious  injury,  which  it  be- 
hoves surgeons  to  be  well  acquainted  with.  A 
successful  mode  of  managing  such  cases  has 
not  yet  been  exemplified.* 

2.  Fracture  of  the  superior  extremity  of  the 
femur. — The  head  of  the  femur  is  so  protected 
by  the  acetabulum,  that  it  is  seldom  or  never 
fractured,  except  by  gunshot  injuries.  The 
neck  and  rest  of  its  superior  extremity  are, 
however,  we  find,  subjected  to  various  accidents. 
The  general  symptoms  of  fractures  of  the  neck 
and  upper  extremity  of  the  femur  are,  that  the 
affected  limb  is  shorter  than  the  other,  the  heel 
vises  to  the  level  of  the  opposite  malleolus,  the 
patella,  leg,  and  foot  seem  much  everted;  there 
is  a  flattening  of  the  natis,  and  a  fulness  of  the 
groin.  The  patient  does  not  attempt  to  stand, 
much  less  to  walk.  There  is  in  the  part  itself, 
as  ft  were,  a  conscious  inability  to  support  the 
weight  of  the  body,  and  even  when  the  patient 
is  lying  on  a  horizontal  plane,  as  in  bed,  we 
find  that  be  cannot,  by  the  unassisted  effort  of 
the  muscles  of  the  injured  limb,  elevate  it  from 
the  horizontal  level,  upon  which  it  lies  power- 
less. When  the  surgeon,  standing  at  the  foot 
of  the  bed,  seizes  the  affected  limb,  and  pulls 
it  towards  him,  so  as  gradually  to  overcome  the 
contractile  power  of  the  muscles,  the  limb  is 
restored  to  its  natural  length,  and  if  now  we 
resort  to  the  painful  expedient  of  rotating  the 
thigh,  crepitus  is  rendered  manifest.  When- 
ever the  surgeon  relaxes  the  force  by  which  the 
limb  was  restored  to  its  natural  length,  the 
shortening,  eversion,  and  deformity  of  the  limb 

*  In  the  twelfth  volume  of  the  Dublin  Medical 
Journal,  Mr.  R.  Smith  has  made  some  valuable 
observations  on  this  case,  in  relation  to  the  diag- 
nosis of  obscure  cases  of  injury  of  the  hip  and 
shoulder-joints. 


recur.  Such  are  the  general  signs  of  fracture 
of  the  upper  extremity  of  the  thigh-bone. 
The  portion  of  the  bone,  called  the  neck,  may 
be  fractured  transversely  with  respect  to  the 
direction  of  its  long  axis,  either  within  or  with- 
out the  capsular  ligament.  The  first  is  deno- 
minated the  intracapsular  fracture,  the  second 
the  extra-cupsular  fracture.  Oblique  fractures 
of  the  neck  of  the  bone  are  not  impossible. 

A.  Intra-capsular  fracture  of  the  neck  of 
the  femur.  —  This  fracture  has  been  seldom 
seen  in  the  young  subject,  but  is  one  of  the 
most  common  accidents  to  which  elderly  peo- 
ple are  liable.  In  such  persons  many  cir- 
cumstances in  their  organization  appear  to  ac- 
count for  their  great  liability  to  this  accident. 
Their  muscles  have  lost  their  firmness,  and  are 
more  or  less  in  a  state  of  atrophy  ;  the  trochan- 
ter major  becomes  peculiarly  prominent;  the 
neck  of  the  femur  yielding  somewhat,  perhaps, 
to  the  weight  of  the  body,  descends  and  loses 
some  of  its  obliquity.  This  atrophy  of  the 
muscles  and  bones  is  not  so  frequently  noticed 
in  the  male  as  in  the  elderly  female,  in  whom 
the  breadth  of  the  pelvis  is  greater  and  the  tro- 
chanter major  more  projecting.  These  obser- 
vations account  sufficiently  for  the  great  liability 
to  the  intra-capsular  fracture,  which  we  notice 
in  the  elderly  subject,  and  for  the  more  fre- 
quent occurrence  of  the  accident  in  the  aged 
female  than  in  the  male.  In  the  young  subject 
the  trochanter  major  does  not  project  so  much, 
the  muscles  surrounding  the  hip-joint  are  re- 
markably firm,  and  when  falls  on  the  side 
occur,  the  surrounding  muscles  and  the  os  in- 
nominatuin  share,  with  the  great  trochanter,  the 
weight  of  the  fall.  The  bone  in  the  young 
subject  is  better  calculated  from  its  form  and 
its  organization  to  resist  the  effects  of  falls  on 
the  trochanter,  and  in  these  fractures  of  the 
neck  of  the  femur  have  been  rarely  witnessed. 
In  the  young  subject,  too,  the  neck  of  the 
femur  is  comparatively  shorter  than  in  the  aged, 
the  angle  of  union  of  the  neck  with  the  shaft  of 
the  bone  is  more  open,  and  the  axes  of  both 
neck  and  shaft  are  more  in  a  line.  The  great 
proportion  of  animal  matter  existing  in  the 
bones  of  the  young,  and  consequent  elasticity 
of  the  bone,  render  it  capable  of  resisting  frac- 
ture, while,  on  the  contrary,  the  comparative 
deficiency  of  animal  matter,  and  the  consequent 
redundancy  of  earthy  material  in  the  aged  sub- 
ject, render  the  neck  of  the  femur  friable.  In 
a  word,  the  tissue  of  the  bones  in  general  does 
not  escape,  in  the  aged,  that  atrophy  which 
affects  the  rest  of  the  system,  and  when  we  re- 
collect the  functions  which  the  neck  of  the 
thigh-bone  has  to  perform,  we  shall  not  be  sur- 
prised to  learn  that  the  effects  of  this  atrophy 
are  more  readily  felt  and  seen  in  this  part  of 
the  osseous  system  than  perhaps  any  other. 
The  superincumbent  weight  of  the  body  and 
the  action  of  muscles  must  have  a  tendency  to 
diminish  the  obliquity  of  the  neck  of  the  thigh- 
bone, to  render  it  more  horizontal,  and  conse- 
quently less  capable  of  bearing  up  against  the 
effects  of  concussion. 

Besides  the  loss  of  obliquity  of  the  neck  of 
the  thigh-bone,  we  find  two  other  circumstan- 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


805 


ces  relative  to  the  neck  of  the  bone  itself,  ren- 
dering it  very  liable  to  fracture  in  the  aged.  I 
mean  the  expansion  of  the  cells,  by  which  the 
strength  of  the  interior  of  the  bone  is  dimi- 
nished ;  and,  secondly,  by  the  partial  removal 
by  absorption  of  that  long  bony  arch  of  com- 
pact tissue,  upon  which  in  the  adult  depends, 
vve  believe,  the  principal  strength  of  the  neck 
of  the  bone  (Jig.  318)  ;  and  even  in  many  aged 
subjects,  vve  find  the  partitions  of  the  bony 
cells  removed,  and  a  large  cavity  filled  with 
fatty  medulla  occupies  the  centre  of  the  cervix 
femoi'is.  All  these  alterations  obviously  weaken 
this  portion  of  the  thigh-bone,  and  vve  feel  very 
little  doubt  but  that  when  the  condition  of  the 
bone  above  alluded  to  exists,  even  without  a 
fall  a  fracture  may  occur.  We  have  noticed 
specimens  of  senile  degeneration  of  the  neck  of 
the  femur  in  museums,  in  which  the  neck  of 
the  femur  had  been  removed  gradually  by  ab- 
sorption, so  that  the  head  of  the  bone  had  ap- 
proximated to  the  trochanters.  Such  specimens, 
where  the  history  of  the  case  was  unknown, 
have,  vve  doubt  not,  been  from  time  to  time 
adduced  as  evidences  in  favour  of  the  possibi- 
lity of  bony  consolidation  of  the  intra-capsular 
fracture.  These  observations  on  the  effects  of 
senile  degeneration  of  the  neck  of  the  thigh- 
bone sufficiently  account  for  the  remarkable 
frequency  of  the  intra-capsular  fracture  of  the 
cervix  fernoris  in  the  aged  subject  from  the 
most  trivial  causes.  The  fracture,  under  such 
circumstances,  should,  in  our  minds,  be  looked 
upon  more  as  a  stage  of  morbid  alteration, 
from  which  no  amendment  is  to  be  expected, 
than  as  an  accidental  lesion,  which  the  efforts 
of  nature  and  the  aid  of  surgery  can  be  deemed 
adequate  to  repair. 

B.  Extra-capsular  fracture  of  the  neck,  and 
fracture  of  the  superior  portion  of  the  shaft 
the  femur. — Fracture  of  the  neck  of  the  femur 
may  occur  in  a  part  of  the  bone  immedi- 
ately external  to  the  synovial  sac  and  capsu- 
lar ligament;  it  may  pass  obliquely  through 
the  cervix  fernoris  and  trochanters,  or  it  may 
occur  in  the  cellular  and  spongy  portion  of  the 
bone  which  is  immediately  external  to  these 
processes.  In  all  these  cases  the  accident  is 
usually  met  with  in  young  and  vigorous  indivi- 
duals, and  is  often  very  severe.  There  is  in 
these  cases  much  deformily,  great  eversion  of 
the  limb,  with  considerable  shortening  and 
swelling.  The  fracture  having  traversed  the 
bone  external  to  the  capsular  ligament,  there 
is  but  little  to  resist  the  full  force  of  muscular 
action  upon  the  lower  fragment  of  the  bone, 
while  the  upper  is  forced  downwards  by  the 
weight  of  the  body,  so  that,  from  both  these 
causes,  much  shortening  is  produced.  The 
muscles  are  in  a  state  of  spasm,  and  at  first 
resist  the  surgeon's  efforts  to  bring  down  the 
limb  to  its  normal  length.  The  muscles  gra- 
dually yield  to  gentle  and  continued  extension, 
and  if  now  a  movement  of  rotation  be  commu- 
nicated to  the  broken  femur,  a  crepitus  can  be 
felt  by  the  hand  pressing  on  the  great  trochan- 
ter, which  on  rotation  of  the  femur  is  perceived 
to  move  in  a  small  circle.  Fversion  of  the 
whole  limb,  in  cases  of  fracture  of  the  upper 
extremity  of  the  femur,  has  been  noticed  as 


one  of  its  most  prominent  symptoms,  and  the 
cause  of  it  may  be  fairly  attributed  to  the  pre- 
ponderating influence  of  the  rotators  outwards, 
to  which  the  lower  fragment  is  abandoned 
when  fracture  has  occurred  :  the  rotators  out- 
wards are  the  glutaeus  maximus,  the  three  ad- 
ductors, the  pectinalis,  the  psoas  magnus,  and 
iliacus  internus,  together  with  the  obturators, 
pyriformis,  and  other  muscles,  inserted  into  the 
posterior  inter-trochanteric  line.  These  mus- 
cles are  solely  opposed  by  the  rotators  inwards, 
which  are  few  and  comparatively  weak.  Not- 
withstanding the  violence  of  the  injury  in  ge- 
neral, and  the  deformity,  the  prognosis  in  these 
cases  is  much  more  favourable  than  in  the  case 
of  the  intra-capsular  fracture,  because  in  the 
former  a  solid  bony  union  of  the  fragments 
may  be  reasonably  hoped  for. 

In  considering  the  symptoms  of  fracture  of 
the  superior  extremity  of  the  shaft  and  of 
the  neck  of  the  femur,  whether  the  seat  of 
fracture  be  within  or  without  the  synovial  cap- 
sule, it  should  be  recollected  that  extraordi- 
nary cases  may  occur;  thus  there  may  be 
fracture  combined  with  inversion  of  the  limb. 
The  cause  of  this  inversion,  in  particular  cases, 
has  been  sought  for,  and  Mr.  Guthrie  gives 
ingenious  anatomical  reasons  for  this  rare  symp- 
tom, depending  upon  the  line  of  direction  the 
fracture  may  have  taken  ;  if,  for  example,  the 
fracture  may  have  taken  such  a  course  as  to 
detach  from  the  shaft  of  the  femur  the  neck, 
and  at  the  same  time  also  the  lesser  trochanter, 
to  which  is  attached  the  great  rotator  outwards, 
the  psoas  and  iliacus,  and  if  at  the  same  time 
the  attachments  of  the  gemini,  obturators,  and 
pyriformis  be  destroyed,  in  this  case  Mr.  Guthrie 
supposes  that  there  is  an  anatomical  reason  for 
the  rotation  inwards,  as  the  tensor  vaginas  ferno- 
ris and  the  anterior  fibres  of  the  glutaeus  me- 
dius  remain  unopposed.  This  explanation  is 
ingenious,  but  the  cause  of  occasional  inversion 
of  the  limb  in  fracture,  noticed  by  Petit,  De- 
sault,and  all  subsequent  writers,  has  not  yet,  in 
our  mind,  been  sufficiently  elucidated.  The 
phenomenon  of  inversion  of  the  foot,  in  cases 
of  fracture  of  the  upper  extremity  of  the  femur, 
is  extremely  rare,  but  it  has  been  noticed  in 
the  intra-capsular  fracture,  (Stanley,  Smith,) 
in  the  extra-capsular  fracture,  (Guthrie,)  and 
we  have  ourselves  seen  it  in  all  these  cases. 
The  deviation  inwards,  says  Dupuytren,  is  so 
rare,  that  we  can  scarcely  reckon  upon  meeting 
it  once  in  a  hundred  cases.  The  surgeon  of  the 
Hotel  Dieu  attributes  much  of  the  rotation  out- 
wards in  fractures  of  the  neck  of  the  thigh-bone 
to  the  action  of  the  adductor  muscles,  but  adds, 
"  il  faut  dire  aussi,  qu'on  notice  presqueaucune 
partie  d'une  autre  cause,  qui  cependant  peut 
seule  rendre  compte  de  la  deviation  en  dedans, 
et  apprendre  a  y  remedier.  Je  veux  parler  de 
I'obliquite  des  fragmens  dans  la  fracture  du  col 
du  femur,  si  le  fragment  interne  se  porte  en 
arricre,  et  l'externe  en  avant,  il  y  a  alors  devia- 
tion en  dehors.  Si,  au  contiaire,  la  fracture  est 
oblique,  en  sens  inverse,  la  deviation  aura  lieu 
en  dedans.  C'est  done  par  I'obliquite  des  frag- 
mens, que  ces  varietts  de  deviation  peuvent 
ctre  appreciees." 

C.  Fracture  of  the  neck  of  the  femur,  compli- 


806 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


cated  with  fracture  through  the  trochanter 
major. — In  the  thirteenth  volume  of  the  Medico- 
Chirurgical  Transactions,  Mr.  Stanley  has  re- 
marked that  among  the  more  complicated  inju- 
ries to  which  the  hip-joint  is  liable,  that  of 
fracture  of  the  trochanter  major,  combined  with 
fracture  of  the  neck  of  the  femur,  has,  under 
certain  circumstances,  a  strong  resemblance  to 
dislocation  of  this  bone.  Whenever  the  frac- 
tured portions  of  the  trochanter  can  be  brought 
into  contact,  a  crepitus  will  be  perceived,  which 
will  enable  the  surgeon  to  ascertain  the  precise 
nature  of  the  injury  ;  but  when  from  the  direc- 
tion of  the  fracture,  one  portion  of  the  trochan- 
ter major  has  been  drawn  by  the  muscles  to- 
wards the  sciatic  notch,  no  crepitus  can  then  be 
discovered.  A  direct  source  of- mistake  will 
then  arise  from  the  positive  resemblance  of  the 
fractured  portion  of  the  trochanter  to  the  head 
of  the  femur,  the  former  occupying  the  place 
which  the  latter  would  do  in  dislocation,  and 
if,  with  these  circumstances,  there  should  hap- 
pen to  be  inversion  of  the  injured  limb,  the 
difficulty  of  diagnosis  must  be  considerably  in- 
creased. The  writer  has  seen  such  cases  as 
those  alluded  to  by  Mr.  Stanley,  and  when  he 
confined  his  observations  to  the  consideration 
of  the  joint  only,  he  felt  all  the  difficulty  alluded 
to  in  forming  an  opinion ;  but  in  these  cases 
the  limb  can  in  general  be  brought  down  to  its 
natural  length  by  forcible  extension,  and  it  is 
possible,  too,  to  flex  the  thigh  on  the  abdomen, 
which  we  know  to  be  impracticable  in  the  case 
of  luxation.  In  most  of  the  cases  which  the 
writer  has  witnessed  of  the  fracture  traversing 
obliquely  the  superior  extremity  of  the  shaft  of 
the  femur,  detaching  the  trochanters,  the  foot 
and  whole  of  the  injured  extremity  were  everted, 
a  position  it  were  impossible  for  the  limb  to 
assume,  were  the  globular-shaped  head  of  the 
bone  on  the  dorsum  of  the  ilium,  or  placed  to- 
wards the  ischiatic  notch,  and  indeed,  in  the 
cases  which  he  has  seen,  with  inversion  of  the 
limb,  the  inverted  position  was  not  permanent, 
as  when  the  patient  was  raised  out  of  bed,  and 
assisted  to  stand  for  a  few  minutes  on  the 
sound  extremity,  the  injured  limb  gradually 
assumed  an  inclination  forwards  and  outwards; 
the  inclination,  though  slight,  was  always  to  a 
degree  which  it  were  impossible  to  give  to  the 
limb  if  the  head  of  the  bone  were  placed  on 
the  sciatic  notch.  Finally,  as  to  the  remark- 
able symptom  of  inversion  of  the  limb,  com- 
bined with  fracture,  we  have  never  seen  this  in- 
version so  rigid  as  it  is  in  the  luxation ;  the  in- 
version can  be  overcome,  and  we  have  mostly 
found  that  in  the  cases  in  which  this  symptom 
was  noticed,  there  existed  a  comminuted  frac- 
ture of  the  superior  extremity  of  the  shaft  of 
the  femur,  and  the  limb,  if  left  to  itself,  would 
be  found  sometimes  to  be  everted,  sometimes 
to  be  inverted,  and  generally  to  possess  a  re- 
markable degree  of  flexibility,  yielding  to  any 
movements  the  surgeon  wishes  to  communicate 
to  it.  Such  has  been  the  result  of  the  writer's 
individual  observations  on  these  cases. 

D.  Fractures  of  the  neck  of  the  thigh-hone, 
with  impaction  of  the  superior  or  cotyloid  frag- 
ment into  thecancel  luted  tissue  of  the  upper  extre- 
mity of  the  shaft  of  the femur. — We  have  spoken 


of  a  fracture  of  the  neck  of  the  thigh-bone,  in 
which  the  fracture  runs  transversely  with  respect 
to  the  direction  of  the  axis  of  the  neck  of  the 
bone,  and  also  of  oblique  fractures  of  the  cervix 
femoris  (Dupuytren).  In  the  former,  i.  e.  the 
transverse  fracture  of  the  neck,  the  two  opposite 
surfaces  of  the  fragments  are  generally  fairly 
confronted  to  each  other,  and  each  presents  a 
granular  broken  surface ;  but  instances  have 
been  met  with  in  which  there  existed  an  inter- 
locking of  these  surfaces.  A  bony  spicula  or 
dentiform  process,  as  it  were,  has  been  seen  to 
proceed  from  the  broken  surface  of  the  superior 
or  cotyloid  fragment,  and  to  sink  into  an  alveo- 
lar-like depression  on  the  upper  surface  of  the 
lower  fragment ;  to  use  the  words  of  Cruveil- 
hier  :  "  L'engrenement  des  fragmens  s'observe 
moins  souvent,  peut-etre  dans  la  fracture  intra- 
capsulaire  que  dans  la  fracture  extra-capsulaire. 
Cependant  je  l'ai  observee  plusieurs  fois ; 
dans  un  cas  de  fracture  intra-capsulaire  du  col, 
observe  sur  un  adulte  tres  vigoreux,  j'ai  trouve 
un  engrenement  reciproque  forme  ainsi  qu'il 
suite  le  fragment  superieur  et  le  fragment  infe- 
rieur  presentaient  chacun  une  cavite,  et  une 
avance  osseuse ;  la  cavite  de  l'un  recevait 
l'avance  de  l'autre  et  reciproquement,  l'engrene- 
ment etait,  qu'il  y  avait  immobilite  complete." 

In  the  species  of  fracture  which  we  are  now 
about  to  consider,  the  superior  or  cotyloid  frag- 
ment is  firmly  impacted  into  the  cancellated 
structure  of  the  superior  part  of  the  shaft  of  the 
femur.  In  this  case  the  limb  is  shortened 
somewhat,  though  not  much,  and  consequently 
the  case  may  be  mistaken  for  the  intra-capsular 
fracture.  When,  however,  the  surgeon  endea- 
vours to  bring  the  limb  to  its  normal  length, 
and  to  elicit  crepitus,  or  by  rotation  of  the 
femur  he  endeavours  to  ascertain  whether  the 
trochanter  moves  in  a  larger  or  smaller  circle, 
he  finds  that  he  cannot  elongate  the  shortened 
limb,  nor  elicit  crepitus  by  rotation,  nor  can  he 
learn  anything  satisfactory  by  the  movement  of 
the  trochanter.  In  general  the  fracture  is  com- 
plete of  the  compact  and  reticular  tissue  of  the 
neck  of  the  bone,  and  the  upper  fragment  is 
wedged  into  the  lower,  as  is  the  fang  of  a  tooth 
into  its  alveolus ;  but  cases,  we  believe,  have 
occurred,  in  which  the  fracture  of  the  cervix 
femoris  was  incomplete,  and  had  engaged 
merely  the  under  stratum  of  the  compact  tissue 
of  the  neck  of  the  bone.  To  comprehend  well 
what  occurs  in  the  partial  as  well  as  in  the  im- 
pacted fracture,  we  should  attend  a  little  to  the 
normal  anatomy  of  the  interior  of  the  cervix  femo- 
ris, and  the  disposition  of  the  compact  and  reti- 
cular tissue,  a  subject  the  writer  has  elsewhere 
stated  has  been  much  overlooked,  see  Dublin 
Journal,  vol.  vi.  p.  222,  from  which  we  quote  the 
following  words  :  "  Let  us  make  a  vertical  sec- 
tion through  the  neck  of  a  healthy  femur,  in  the 
direction  of  its  long  axis,  and  continue  it  down 
through  the  shaft  of  the  dry  bone,  the  section 
leaving  one-half  of  the  femur  in  front,  and  the 
other  behind  with  the  lesser  trochanter,  as  has 
been  done  in  the  specimen  of  the  healthy  femur 
of  a  well-formed  adult  man,  from  which  Jig.  318 
has  been  taken.  This  simple  view  shews  us,  that 
the  principal  strength  of  the  neck  resides  in  an 
arch  of  compact  tissue,  which  begins  small 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


807 


Fie,  318. 


where  the  globular  head  joins  the  under  part  of 
the  neck,  but  which  gradually  enlarges  down- 
wards towards  the  lesser  trochanter,  and  even 
so  low  as  the  middle  of  the  femur,  where  it 
will  be  found  nearly  twice  the  breadth  of  the 
opposite  wall  of  the  shaft  of  the  bone ;  the 
compact  stratum  which,  scarcely  thicker  than  a 
wafer,  invests  the  entire  of  the  head,  upper  part 
of  the  neck,  and  trochanter,  seems  to  have  little 
reference  to  any  design  of  imparting  strength  or 
resistance  to  this  portion  of  the  bone,  and  the 
same  may  be  said  of  the  whole  of  the  reticular 
tissue  of  these  processes,  while,  on  the  contrary, 
the  compact  tissue  of  the  under  surface  of  the 
neck  seems  artfully  arranged,  if  we  can  so  say, 
so  as  to  give  support  to  the  weight  of  the  body 
in  the  erect  position  ;  hence  do  we  find  this 
compact  stratum  thrown  into  an  arch,  upon 
which  the  weight  of  the  body  falls,  as  that  of  a 
carriage  does  on  the  C  spring  which  sustains  it. 

When  we  fall  or  leap  from  a  height  on  the 
feet  or  knees,  the  thin  upper  stratum  of  the 
neck,  and  the  whole  of  the  reticular  tissue  of 
the  bone  will  first  receive,  and  probably  yield 
somewhat  to,  the  weight,  by  which  some  of  the 
force  of  the  shock  may  be  decomposed,  but  to 
the  bony  arch  of  compact  tissue,  to  which  we 
have  alluded,  must  ultimately  be  referred  any 
violence  which  the  neck  of  the  femur  can  re- 
ceive from  any  impulse  transmitted  from  above. 

We  seldom  hear  of  a  fracture  of  the  neck  of 
the  femur  occurring  to  a  healthy  adult  when  he 
falls  with  violence  on  his  feet  or  knees,  for  the 
weight  of  the  superincumbent  body  is  thrown 
in  the  most  favourable  manner  on  the  bony 
arch  of  compact  tissue  before  alluded  to,  which 
from  its  density  and  form,  and  strength  deriva- 
ble from  both,  it  is  almost  always  able  to 
resist;  and  even  a  fracture  of  the  acetabulum 


or  rupture  of  the  capsular  ligament  and  dislo- 
cation are  accidents  more  likely  to  happen 
under  these  circumstances. 

But,  on  the  other  hand,  let  us  suppose  a 
person  to  fall  on  the  trochanter  major,  which  is 
resisted  by  the  ground,  while  the  weight  of  the 
pelvis,  &c.  acting  obliquely  on  the  under  sur- 
face of  the  neck,  will  have  a  tendency  to  bring 
the  neck  of  the  femur  into  a  straight  line  with 
the  shaft  of  the  bone,  or  in  other  words,  to 
efface  its  obliquity  ;  here  the  compact  tissue,  so 
often  alluded  to,  receives  the  force  from  below 
in  a  most  unfavourable  manner,  and  this  tissue 
cracks  across,  and  if  no  more  happens  for  the 
present,  we  shall  have  the  simplest  form  of 
partial  fracture  of  the  neck  of  the  femur. 

While  circumstances  are  in  this  state,  we 
can  conceive  the  possibility  of  a  patient  being- 
able  to  stand  after  such  an  accident,  and  even 
walk  for  some  distance;  and  when  examined 
by  the  surgeon,  we  can  understand  how  the 
latter,  as  it  has  often  happened,  might  be  de- 
ceived into  the  opinion  that  there  was  really  no 
fracture.  Again,  we  can  easily  imagine  how 
under  such  circumstances  an  awkward  move- 
ment or  a  fall  may  render  the  fracture  complete, 
or  how,  from  a  severe  secondary  injury,  or  even 
the  continued  action  of  the  first  impulse,  some- 
what varied  in  its  direction,  the  upper  fragment 
of  the  broken  neck  of  the  femur  could  be 
wedged  into  the  cancelli  of  the  shaft. 

Anatomical  characters  of  fracture  of  the 
neck  of  the  thigh-bone.- — In  those  cases  in  which 
opportunities  have  occurred  of  making  recent 
anatomical  examinations  of  those  who  have 
died  shortly  after  having  suffered  fracture  of 
the  neck  of  the  thigh-bone,  blood  has  been 
found  extensively  extravasated  beneath  the  skin, 
among  the  interstices  of  the  muscles,  and  we 
find  the  line  of  the  fractures  through  the  tro- 
chanters and  upper  portion  of  the  shaft  of  the 
femur  itself  marked  out  by  blood  in  a  coagu- 
lated state,  which  had  insinuated  itself  into  and 
among  the  interstices  of  the  broken  bones. 
When  we  examine  a  case  of  intra-capsular 
fracture  which  had  taken  place  a  long  time 
previously  to  the  death  of  the  patient,  very 
remarkable  changes  in  the  structures  around 
the  joint  are  noticed.  The  muscles,  when  com- 
pared with  those  of  the  opposite  side,  are  more 
or  less  atrophied.  This  observation,  however, 
only  applies  to  the  greater  number  of  the 
muscles  around  the  hip-joint,  as  some  of  the 
smaller  ones  (in  cases  of  ununited  fractures  of 
the  neck  of  the  thigh-bone  of  long  standing) 
are  usually  found  to  have  undergone  a  con- 
siderable change  in  their  appearance  and  struc- 
ture; of  all  these,  the  obturator  externus  seems 
to  be  the  most  changed  and  thickened.  This 
is  easily  accounted  for,  uhen  we  recollect  that 
when  the  neck  of  the  femur  is  fractured,  there  is 
a  strong  tendency  in  the  muscles  around  the  joint 
to  drag  up  the  femur,  and  cause  its  shortening  ; 
indeed,  the  capsular  ligament  and  the  obturator 
externus  alone  resist  the  ascent  of  the  head  of 
the  bone  on  the  pelvis.  The  tonic  force  of  the 
muscles  has  constantly  this  tendency  to  elevate 
the  femur  on  the  dorsum  of  the  ilium,  and 
when  the  patient  begins  to  walk,  and  to  throw 


808 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


his  weight  on  the  fractured  limb,  then  it  is 
more  particularly  that  the  power  of  the  obtu- 
rator externus  is  called  into  action  to  restrain 
the  ascent  of  the  trochanter  major,  which  is 
kept  downwards  by  the  obturator  and  by  the 
strength  of  the  capsular  ligament,  which  under- 
goes a  corresponding  change  of  structure.  The 
capsular  ligament  has  been  found  semi-cartila- 
ginous, and  occasionally  even  spiculae  of  bone 
have  been  found  in  it ;  we  have  also  known  it 
to  be  much  elongated,  so  as  to  allow  the  lower 
fragment  to  ascend  much  on  the  dorsum  of  the 
ilium.    We  have  found  the  capsular  ligament 
usually  entire  in  old  cases,  but  occasionally  the 
bursa,  which  exists  in  front  of  or  under  the 
psoas  muscle,  seems  to  have  freely  communi- 
cated with  the  interior  of  the  joint.    In  some 
cases  the  natural  thickness  of  the  capsule  is 
not  much  increased;  in  others  it  is  very  con- 
siderably so.    In  one  of  the  cases  alluded  to 
by  Mr.  Colles,  the  capsular  ligament  was  a 
quarter  of  an  inch  thick,  in  some  places  half  an 
inch,  and  it  had,  at  the  same  time,  a  firmness 
of  texture  which  might  be  termed  semicartila- 
ginous.    Two  or  three  particles  of  bone  were 
found  in  it.    The  synovial  membrane,  where  it 
meets  the  neck  of  the  femur,  has  been  fre- 
quently found  lacerated  in  recent  cases;  in 
older,  inflamed,  and  in  older  still,  adhesions  of 
the  synovial  structures  to  each  other  have  been 
observed.    Thus  the  head  of  the  fractured 
femur  lias  been  found  adherent  to  the  acetabu- 
lum, and  we  have  frequently  found  filamentous 
adhesions  between  the  synovial  membrane  of 
the  neck  of  the  bone  and  the  interior  of  the 
synovial  lining  of  the  fibrous  capsule.  The 
synovial  membrane,  in  the  normal  state,  where 
it  invests  the  narrowest  part  of  the  neck  of  the 
bone,  is  thrown  into  longitudinal  plicae  or  folds; 
some  of  the  lowest  and  most  distinct  of  these 
are  denominated  by  Weitbrecht  "  retinacula." 
We  do  not  believe  that  this  accurate  anatomist 
gave  this  name  to  these  fibro-synovial  folds 
with  any  practical  knowledge  of  the  functions 
which  they  occasionally  perform  in  cases  of 
fracture ;  but  we  know  very  well  by  experience 
that,  in  recent  cases  of  the  simple  intra-capsular 
fracture  of  the  neck  of  the  femur,  it  very  fre- 
quently, if  not  generally,  happens  that,  although 
the  neck  of  the  femur  is  broken  transversely 
with  respect  to  its  longitudinal  axis,  the  cylin- 
der of  fibro-synovial  membrane,  which  is  re- 
flected over  the  neck  of  the  bone,  is  sometimes 
left  unbroken,  or  is  only  partially  lacerated. 
The  fibrous  periosteum,  which  is  here  added  to 
the  synovial  investment  of  the  neck  of  the 
femur,  strengthens  much  this  part  of  the  mem- 
brane, and  both  together,  in  cases  of  intra-cap- 
sular fractures,  serve  the  purpose  of  keeping 
nearly  in  apposition  the  broken  fragments;  and 
in  cases  in  which  the  greater  part  of  this  cylin- 
drical investment  of  the  neck  of  the  bone  re- 
mains entire,  or  nearly  so,  the  unbroken  mem- 
brane and  the  vessels  which  pass  along  it  must 
be  the  medium  of  vascular  communication  be- 
tween the  fragments. 

Thephenomena  which extra-capsulnr  fractures 
present  are  not  unlike  those  which  are  the  result 
of  fractures  elsewhere  of  the  femur.    We  may 


remark,  however,  that  one  of  the  results  of  this 
lesion  of  the  neck  of  the  femur  (as  it  is,  in- 
deed, of  almost  all  other  injuries  or  alterations 
of  structure  of  this  part  of  the  bone)  is,  that 
the  posterior  part  of  the  neck  of  the  femur  is 
diminished  one-half  in  its  normal  length ;  the 
posterior  inter-trochanteric  ridge  of  bone  ap- 
proaches to  within  half  an  inch  of  the  circular 
line  which  marks  the  junction  of  the  head  and 
neck  of  the  bone.  A  large  quantity  of  callus 
is  usually  thrown  out  in  the  line  of  the  extra- 
capsular fracture,  and  the  trochanter  major  be- 
comes much  deformed  by  it,  and  the  neck  so 
much  shortened,  that  there  is  danger  of  the 
motions  of  the  hip-joint  being  interfered  with. 

In  recent  cases  in  which  intra-capsular  fracture 
had  occurred,  little  or  no  change  has  been  ob- 
served worth  noticing ;  but  in  old  cases  several 
phenomena  of  importance  present  themselves. 
1st,  In  some  cases  we  find  a  false  articulation 
to  have  been  formed ;  2dly,  there  is  union  of 
the  broken  surfaces  of  the  upper  and  lower 
fragment  by  means  of  ligamentous  bands; 
3dly,  it  is  reported  that  complete  bony  union 
is  effected,  but  the  controversy  upon  this  sub- 
ject can  scarcely  be  said  to  be  yet  terminated. 

Very  soon  after  intra-capsular  fracture  has 
occurred,  the  surfaces  of  the  broken  frag- 
ments undergo  changes  ;  they  are  smoothed  off 
by  the  power  of  the  absorbents,  or  are  mechani- 
cally rubbed  down  by  the  friction  of  the  broken 
surfaces,  or  by  both  these  processes  combined. 
In  general  the  neck  of  the  femur  disappears 
altogether,  and  the  basis  of  the  head  of'  the 
bone  corresponds  to  the  level  of  the  circular 
brim  of  the  acetabulum.  The  surfaces  are  ge- 
nerally brought  into  contact  by  the  muscles, 
and  frequently  adhesions  are  formed  between 
the  neck  of  the  bone  and  the  internal  surface 
of  the  capsular  ligament,  which,  as  has  already 
been  remarked,  is  greatly  thickened  ;  an  oily 
fluid,  resembling  natural  synovia,  is  shed  over 
the  broken  surfaces,  and  here  are  all  the  ele- 
ments of  a  false  articulation  present.  The  tro- 
chanters are,  in  consequence  of  the  removal  of 
the  neck  of  the  bone,  brought  near  to  the  edge 
of  the  acetabulum,  and  bony  growths  generally 
shoot  out  from  these  processes  and  from  the 
inter-trochanteric  line  posteriorly.  These  bony 
projections  or  vegetations  sometimes  rise  as 
high  as  the  edge  of  the  acetabulum,  and  when 
the  patient  stands  or  walks,  these  bony  growths 
rising  up  from  the  trochanter  are  supposed  to 
afford  a  prop  to  the  pelvis,  and  thus  to  assist 
somewhat  the  structures  which  perform  the 
functions  of  the  false  articulation.  It  has  been 
noticed  that,  in  general,  the  removal  of  bone 
from  the  upper  fragment  extends  as  far  as  the 
basis  of  the  head  and  the  level  of  the  circular 
brim  of  the  acetabulum;  but  in  some  cases  this 
fragment  has  been  hollowed  out.  Again,  in 
obedience  to  influences  which  we  cannot  ex- 
plain, it  has  happened  that  the  lower  surface  of 
the  upper  fragment  formed  an  uniform  convex 
surface,  looking  downwards,  and  corresponded 
to  a  large  excavation  formed  in  the  substance 
of  the  great  trochanter.  This,  we  find,  occurred 
in  one  of  Mr.  Colles's  cases  :  the  lower  surface 
of  the  upper  fragment  was  convex,  and  covered 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


809 


with  spots  resembling  ivory,  while  the  upper 
surface  of  the  lower  fragment  was  widely  ex- 
panded into  a  cup.    We  have,  in  our  museum, 
a  very  remarkable  specimen  of  this  abnormal 
condition  of  the  hip-joint.    The  upper  or  coty- 
loid fragment  seems  united  to  the  acetabulum 
by  an  imperfect  anchylosis,  while  the  lower 
surface  of  this  fragment  represents  perfectly  the 
half  of  a  sphere  looking  downwards  ;  the  neck 
of  the  femur  has  been  entirely  removed,  and  a 
cup  is  hollowed  out  in  the  great  trochanter  to 
receive  the  convex  surface  of  the  upper  frag- 
ment above  alluded  to.    This  surface,  as  well 
as  the  cavity  formed  in  the  trochanter,  have  the 
polish  and  hardness  of  ivory.    The  history  of 
the  case,  as  to  how  the  functions  of  the  joint 
had  been  performed,  is  unknown.    The  patient 
died  in  the  Richmond  Hospital,  under  the  care 
of  Dr.  Hutton,  of  a  disease  unconnected  with 
the  chronic  affection  of  the  hip-joint.    In  the 
examination  of  old  cases  of  intra-eapsular  frac- 
ture, we  have  found  the  capsular  ligament  short 
and  strong,  as  already  mentioned,  and  that  it 
retained  the  trochanters  close  to  the  brim  of  the 
acetabulum,  the  cervix  femoris  having  been 
altogether  removed.    In  a  case  which  Mr.  Bra- 
bazon  and  the  writer  examined  lately,  of  an  old 
woman  who  had  fractured  the  neck  of  her 
femur  several  years  before  her  death,  and  in 
whom  there  was  shortening  of  the  extremity  for 
two  inches  and  a  half,  the  neck  of  the  femur 
had  altogether  disappeared  to  its  base  The 
surface  on  the  internal  part  of  the  shaft  of  the 
femur,  from  which  the  neck  of  the  bone  nomi- 
nally springs,  was  plane  and  smooth,  and  no 
vestige  even  of  the  lesser  troeVianter  existed. 
The  under  surface  of  the  globular-shaped  head 
of  the  femur  was  removed  to  the  exact  level  of 
the  brim  of  the  acetabulum,  in  which  the  re- 
mainder of  the  head  was  still  retained  by  an 
inter-articular  ligament,  which  seemed  to  have 
been  reduced  to  the  structure  of  loose  cellular 
membrane.    The  acetabulum  of  this  side,  too, 
was  evidently  smaller  than  that  of  the  opposite 
side,  and  the  cartilage  covering  it,  and  that  also 
investing  the  remnant  of  the  head  of  the  bone, 
were  partially  removed.    From  want  of  use,  it 
would  appear  that  all  these  parts  were  in  a 
state  of  atrophy.    In  this  respect  there  was  a 
correspondence  between  the  internal  and  exter- 
nal structures  of  the  broken  limb,  for  the  whole 
extremity  was  deformed,  shortened,  and,  as  is 
usual,  much  reduced  in  size  when  compared 
with  the  opposite  limb.    Union  by  means  of 
a  ligamento-cartilaginous  substance  is  by  no 
means  uncommon.    In  this  case,  as  in  almost 
all  others,  the  neck  of  the  thigh-bone  altogether 
disappears,  and  the  trochanters  are  brought  up 
to  the  level  of  the  acetabulum,  which  still  re- 
tains the  remnant  of  the  head  of  the  bone.  The 
broken  surfaces  are  united  closely  enough  to 
each  other  by  a  fibrous  substance,  and  this 
union  is  sufficiently  analogous  to  that  which 
we  frequently  see  in  cases  of  fractured  olecra- 
non or_patella. 

We  have  spoken  of  a  species  of  fracture 
which  is  called  the  impacted  fracture.  In  this 
case  the  femur  is  broken  generally  at  the  basis 
of  the  neck,  not  far  from  the  inter-trochanteric 


lines :  sometimes  it  is  only  the  under  part  of 
the  neck  which  is  broken,  and  then  the  frac- 
ture is  only  partial ;  but  generally  the  compact 
tissue  all  round  this  portion  of  the  neck  is,  by 
an  accident,  cracked  across,  and  the  superior 
fragment,  that  is,  the  whole  of  the  cervix  femoris, 
is  impacted  into  the  cellular  structure  of  the 
superior  extremity  of  the  shaft  of  the  femur 
(figs.  319,  320).  The  limb  is  shortened  half  an 
inch,  and  in  general  everted.  In  the  Dublin 
Hospital  Reports,  vol.  ii.  Mr.  Colles  has  given 
a  aood  delineation  of  this  species  of  fracture. 
In  Sir  A.  Cooper's  work,  also,  similar  specimens 
maybe  seen  of  this  impaction  of  the  upper  frag- 
ment. "  La  realite  de  ce  fait  interessant"  seemed 
new  to  the  editors  of  Dupuytren's  "  Lemons 
Orales,''  in  1832,  in  which  we  find  it  stated  that 
the  superior  fragment  of  the  broken  neck  of  the 
thigh-bone  is  sometimes  driven  into  the  thick- 
ness of  the  spongy  texture  of  the  superior  ex- 
tremity of  the  inferior  fragment,  and  the  conso- 
lidation is  effected  readily  enough.  To  con- 
clude in  the  words  of  the  Lecons  Orales  : 
"  plusieurs  pieces  d'anatomie  pathologique, 
tirees  du  Museum  de  l'Hotel  Dieu,  et  represen- 
tant  les  fragmens  ainsi  consolides,  ont  ete  mon- 
trees  a  l'amphitheatre,  et  ont  convaincu  chacun 
de  la  realite  de  ce  fait  interessant.  II  est  utile 
de  noter  cette  cause  de  deviation;  elle  peut 
rend  re  compte,  suivant  les  cas,  de  quelques  faits 
exceptionnels  de  deviation  du  pied  en  dedans 
dans  la  fracture  du  col  du  femur,  faits  excep- 
tionnels, qui  ont  ete  observes  par  plusieurs 
auteurs."*  In  the  museum  of  the  Richmond 
Hospital  we  have  some  specimens  of  this  frac- 
ture. Fig.  319  represents  a  section  of  the  supe- 


Fig.  319. 


rior  extremity  of  the  femur  of  a  woman  who 
met  with  this  species  of  fracture.  The  history 
of  her  case,  as  recorded  in  the  catalogue,  is  as 
follows  :— "  Mary  M'Manus,  a;t.  52.  Fracture 
of  the  neck  of  the  femur  external  to  the  cap- 
sule. The  upper  fragment  has  been  driven 
down,  and  has  become  firmly  impacted  in  the 
cancelli  of  the  shaft  of  the  bone.    The  trochan- 

*  Lemons  Orales,  torn.  ii.  p,  100. 


810 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


ter  minor  is  split,  the  fissure  passing  at  right 
angles  with  the  body  of  the  femur.  The  de- 
scending ramus  of  the  pubis  was  broken  ob- 
liquely, the  fracture  passing  downwards  and 
inwards  from  the  thyroid  foramen.  There  was 
a  large  effusion  of  blood  into  the  crushed  can- 
celli  of  the  bone.  Tlie  patient,  from  whom  the 
preparation  was  taken,  was  thrown  down  by  a 
cart  loaded  with  hay.  The  horse  and  cart 
passed  over  her.  The  injured  limb  was  short- 
ened three  quarters  of  an  inch,  the  foot  was 
everted,  and  the  slightest  motion  was  painful. 
She  died  on  the  fourth  day  after  the  occurrence 
of  the  accident,  having  never  recovered  from 
the  shock."  Another  specimen  (Jig.  320)  shews 


Fig.  320. 


this  species  of  fracture  in  the  case  of  a  woman 
who  survived  the  accident.  "  Alicia  Sherlock, 
aet.  64.  Section  of  the  head  and  neck  of  the 
femur,  shewing  fracture  of  the  cervix  external 
to  the  capsule.  The  neck  of  the  bone  has  sunk 
nearly  to  a  right  angle  with  the  shaft.  The 
compact  structure  which  lines  the  concavity  of 
the  cervix  has  been  broken,  while  the  very 
thin  stratum  which  invests  the  upper  surface 
has  yielded  to  the  force  without  breaking,  but 
the  cervix  has  sunk  into  the  cancellated  texture 
of  the  shaft  at  a  right  angle,  and  is  now  sup- 
ported upon  the  lesser  trochanter.  There  is  no 
motion  whatever  between  the  broken  surfaces, 
nor  the  slightest  trace  of  fracture  at  the  central 
part  of  the  neck  of  the  bone.  The  injury  was 
produced  by  a  fall  on  the  trochanter.  There 
was  but  little  alteration  in  the  position  of  the 
foot,  but  the  tendency  was  to  eversion.  The 
shortening  amounted  to  half  an  inch,  and  cre- 
pitus was  not  distinguishable.  The  patient 
lived  three  months  and  a  half  after  the  receipt 
of  the  injury."  In  both  these  cases  we  have  a 
confirmation  of  our  opinion,  that  the  reduction 
of  the  compact  arch  of  bone  which  occupies 
the  under  surface  of  the  neck  of  the  femur  to  a 
thin  lamina,  predisposes  to  fracture  of  this  por- 
tion of  the  neck  of  the  thigh-bone.  In  the  case 
in  which  the  examination  was  made  four  days 
after  the  accident  (Jig.  319)  we  find,  of  course, 


that  there  was  no  osseous  deposition  around 
the  inter-trochanteric  lines,  but  that,  on  the 
contrary,  in  the  case,  A.  Sherlock,  (Jig.  320), 
which  survived  the  accident  for  more  than  three 
months,  exuberant  growths  of  bone  surrounded 
the  seat  of  fracture,  and  contributed  to  form  a 
kind  of  socket,  which  received  the  superior 
fragment,  by  means  of  which  the  patient  was 
enabled  to  throw  her  weight  on  the  injured 
limb,  and  even  to  walk.  The  lesser  trochanter, 
in  most  of  the  cases  which  we  have  examined, 
was  greatly  increased  by  bony  depositions,  and 
became  a  prop  to  support  the  head,  and  it  is 
probable  that,  in  these  cases,  the  acetabulum  is 
propped  up  by  the  growths  of  bone  from  the 
shaft  of  the  femur.  "  This  is  a  mode  of  union," 
says  Mr.  Colles,  (alluding  to  the  impaction,) 
"  very  little  inferior  to  callus  in  point  of  firm- 
ness, but  very  different  in  its  nature,"  and 
which,  he  conceives,  is  peculiar  to  fracture  of 
the  neck  of  the  thigh-bone.  In  these  cases 
Mr.  Colles  has  found  a  thin  cartilaginous  plate 
every  where  interposed  between  the  neck  and 
shaft.  The  new  osseous  production  could  have 
very  little  assisted  in  keeping  the  fractured 
pieces  in  apposition,  for  it  was  principally 
thrown  out  about  the  trochanters,  a  small  por- 
tion only  being  formed  below  the  neck,  yet  the 
motion  allowed  between  the  fragments  was  so 
very  inconsiderable,  that  it  required  a  close  in- 
spection to  discern  it,  so  that,  in  this  instance, 
the  new  osseous  matter  contributed  very  little 
to  the  consolidation  of  the  broken  bone,  the 
firmness  of  which  (inferior  only  to  bony  anchy- 
losis) must  therefore  be  ascribed  entirely  to  the 
interposed  thin  plate  of  cartilage.  In  one  of 
Mr.  Colles's  cases,  No.  XI.  a  vertical  section 
shewed  that  the  neck  had  been  fractured  near 
to  the  trochanters,  and  lay  across  the  top  of  the 
shaft ;  its  broken  extremity  being  in  contact 
with  the  outer  plate  of  the  shaft.  The  external 
solid  walls  of  the  neck  were  very  thin*  In  a 
specimen  of  fracture  of  the  cervix  femoris, 
which  we  possess  in  our  museum,  the  neck  of 
the  bone  has  been  broken  at  its  basis,  near  the 
inter-trochanteric  lines,  and  was  impacted  nearly 
transversely  into  the  cancellated  structure  of  the 
shaft  of  the  femur,  and  the  force  of  the  fall  was 
so  considerable  that  the  upper  fragment  has 
absolutely  penetrated  the  outer  wall  of  the  tro- 
chanter, and  would  have  been  in  naked  con- 
tact with  the  tendon  of  the  gluteus  maximus, 
had  it  not  been  for  the  existence  of  the  bursa 
there  situated. 

From  the  specimens  that  we  have  examined, 
and  have  in  our  possession,  we  entertain  no 
doubt  but  that  solid  bony  union  may  take 
place  between  the  impacted  cervix  femoris  and 
the  superior  extremity  of  the  shaft  of  the  femur. 
In  all  cases  of  the  impacted  fracture,  when  the 
patient  had  survived  the  accident  for  a  month 
or  more,  whether  the  union  was  complete  or 
incomplete,  exuberant  growth  of  bone  had 
sprung  from  the  inter-trochanteric  lines. 

Does  bony  consolidation  of  the  intra-capsular 
fracture  of  the  cervix  femoris  ever  occur? — 
This  question  has  for  the  last  twenty  years  been 

*  Dublin  Hospital  Reports,  vol.  ii.  p.  351. 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


811 


much  agitated;  Desault,  Platna,  and  John  Bell 
long  ago  expressed  their  opinion  that  a  fracture 
within  the  capsular  ligament  would  not  admit 
of  union  by  callus.  Sir  A.  Cooper  in  his 
Treatise  on  Dislocations  and  Fractures  (p.  127) 
says,  "  In  all  the  examinations  which  I  have 
made  of  transverse  fractures  of  the  cervix  femo- 
ris  entirely  within  the  capsular  ligament,  I  have 
never  met  one  in  which  a  bony  union  had  taken 
place,  or  which  did  not  admit  of  motion  of 
one  bone  upon  the  other.  To  deny  its  possibi- 
lity and  to  maintain  that  no  exception  to  the 
general  rule  can  take  place  would  be  presump- 
tuous, especially  when  we  consider  the  varieties 
of  direction  in  which  a  fracture  may  occur,  and 
the  degree  of  violence  by  which  it  may  have 
been  produced;  as,  for  example,  when  the 
fracture  is  through  the  head  of  the  bone  and 
there  is  no  separation  of  the  fractured  ends,  or 
when  the  bone  is  bioken  without  its  periosteum, 
and  the  reflected  ligament  which  covers  its 
neck  torn,  or  when  it  is  broken  obliquely, 
partly  within  and  partly  externally  to  the  cap- 
sular ligament ;  but  all  I  wish  to  be  understood 
to  say  is,  that  if  it  ever  does  happen,  it  is  an 
extremely  rare  occurrence,  and  that  I  have  not 
met  a  single  example  of  it." 

Sir  A.  Cooper's  opinions,  when  they  were 
published,  particularly  in  Paris,  excited  as- 
tonishment, and  many  observations  were  made 
in  the  clinical  lectures  and  works  of  the  day 
upon  the  supposed  error  of  the  doctrine,  that 
the  intra-capsular  fracture  of  the  neck  of  the 
thigh-bone  was  not  susceptible  of  bony  consoli- 
dation. Messrs.  Roux,  Dupuytren,  and  others 
contended  that  they  had  treated  many  cases  of 
the  intra-capsular  fracture  of  the  neck  of  the 
thigh-bone  successfully,  and  that  bony  consoli- 
dation had  been  effected,  and  besides  shewed 
to  their  classes  what  they  considered  as  decided 
examples  of  such  union  of  this  fracture.  They 
did  not  content  themselves  by  referring  to  living 
cases,  because  these  were  likely  to  be  ques- 
tioned, but  they  produced  various  specimens 
obtained  by  post-mortem  examinations  of  per- 
sons who  had  recovered  from  the  effects  of  the 
fracture,  but  had  died  of  other  disease.  Some 
of  these  specimens  were  examined  by  Mr. 
Crosse,  and  some  were  sent  to  London  to  Sir 
A.  Cooper,  but  they  failed  to  convince  either 
Mr.  Crosse  or  Sir  Astley  that  they  were  true 
instances  of  the  infra-capsular  fracture  consoli- 
dated by  bone.  We  may  say  the  same  of  some 
preparations  in  the  museum  of  the  Royal  Col- 
lege of  Surgeons,  London,  which  were  supposed 
to  be  proofs  of  a  bony  union  of  the  neck 
of  the  thigh-bone  subsequent  to  a  fracture 
within  the  capsular  ligament,  but  says  Mr. 
Wilson,  "  I  have  attentively  examined  these 
two  preparations,  and  cannot  perceive  one 
decisive  proof  in  either  of  the  bone  having 
been  actually  fractured."  One  of  these  cases 
was  published  in  the  Edinburgh  Medical  and 
Surgical  Journal  as  an  example  of  united 
fracture.  The  writer  has  known  many  speci- 
mens adduced  as  proofs  of  bony  consolidation 
of  the  intra-capsular  fracture  of  the  neck  of  the 
thigh-bone,  which,  upon  examination,  were 
found  to  have  been  the  result  of  disease.  The 


neck  of  the  thigh-bone,  we  know,  is  greatly 
shortened  when  the  hip-joint  is  the  seat  of  that 
abnormal  change  which  we  have  stated  to  be 
the  result  of  chronic  rheumatic  arthritis,  but 
in  this  case  the  previous  symptoms,  the  history 
of  the  case,  and  when  these  cannot  be  collected, 
the  state  of  the  acetabulum  and  other  appear- 
ances, sufficiently  point  out  the  difference. 
Again,  the  effect  of  senile  degeneration  of  the 
cervix  femoris  is  very  liable  to  be  mistaken  for 
an  united  intra-capsular  fracture.  In  this, 
however,  the  history  of  the  case,  the  co-existence 
of  the  same  condition  on  both  sides,  the  pene- 
tration of  the  interior  of  the  attenuated  cellular 
structure  by  an  oily  medulla,  and  other  charac- 
ters of  the  senile  degeneration,  will  serve  to 
prevent  false  conclusions.  Lastly,  we  have  also 
frequently  known  specimensof  the  impacted  frac- 
ture, where  the  whole  cervix  has  been  firmly 
driven  into  the  substance  of  the  great  trochanter, 
mistaken  for  examples  of  bony  union  of  the  in- 
tra-capsular fracture.  The  quantity  of  callus  that 
is  in  these  cases  added  to  the  great  and  lesser 
trochanters,  which  encloses  the  impacted  neck 
of  the  bone,  is  calculated  on  a  superficial  exami- 
nation to  induce  erroneous  conclusions,  but  a 
section  of  the  bone,  as  represented  in  fig.  320, 
will  explain  the  true  nature  of  the  case. 

Various  cases  have  been  laid  before  the  pub- 
lic and  read  before  different  learned  societies, 
which  have  been  considered  as  very  decided 
evidences  of  bony  consolidation  of  the  intra- 
capsular fracture  of  the  neck  of  the  femur. 

Case  1. — In  the  year  1827  Mr.  Langstaff 
presented  to  the  Medico-Chirurgical  Society  of 
London  a  specimen  of  what  he  considered  to 
have  been  an  intra-capsular  fracture  united  by 
bone.  The  case  was  that  of  a  woman  who  was 
50  years  of  age  when  the  fracture  occurred. 
She  was  confined  for  nearly  twelve  months  to 
bed  after  the  injury,  and  during  the  remainder 
of  her  life,  that  is,  for  ten  years,  she  walked  on 
crutches.  On  dissection  it  was  found  that  the 
principal  part  of  the  neck  of  the  femur  was 
absorbed,  and  the  head  and  remaining  portion 
of  the  neck  were  united  principally  by  bone, 
and  partly  by  a  cartilaginous  substance.  The 
capsular  ligament  was  immensely  thickened 
and  embraced  the  joint  very  closely,  the  carti- 
laginous covering  of  the  head  of  the  bone  and 
acetabulum  had  suffered  partial  absorption,  the 
internal  surface  of  the  capsular  ligament  was 
coated  with  lymph.  On  making  a  section  of 
the  bone,  it  was  evident  that  there  had  been  a 
fracture  of  the  neck  within  the  capsular  liga- 
ment, and  that  union  had  taken  place  by  osseous 
and  cartilaginous  media.  With  a  view  of  ascer- 
taining whether  there  was  real  osseous  union  the 
bone  was  boiled  many  hours,  which  discoloured 
it,  but  by  destroying  all  the  animal  matter  it 
satisfactorily  proved  the  extent  and  firmness  of 
the  osseous  connexion,  and  the  vacant  spaces 
occupied  with  cartilaginous  matter.  These 
appearances  are  represented  by  a  drawing  made 
shortly  after  boiling.* 

Case  2. — Dr  Brulalour,  surgeon  to  the  hos- 
pital at  Bourdeaux,  sent  to  London  the  parti- 

*  Vol.  xiii.  of  the  Society's  Transactions. 


812 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


culars  of  a  case  of  fracture  of  the  neck  of  the 
femur,  whicli  were  read  before  the  Medico- 
Chirurgical  Society  on  the  5th  of  June,  1827. 
The  following  is  an  abstract  of  it.  Dr.  James, 
an  English  physician,  set.  47,  in  good  health, 
was  thrown  from  his  horse  on  the  20th  of  March, 
1826.  He  fell  directly  on  the  great  trochanter, 
but  got  up  and  walked  a  step  or  two,  which 
occasioned  such  acute  pain  in  the  hip-joint  that 
he  instantly  fell  again.  On  examination  im- 
mediately after  the  accident,  Dr.  Brulalour 
observed  the  principal  signs  of  fracture  of  the 
neck  of  the  femur.  Extension  of  the  limb  was 
kept  up  for  two  months  so  as  to  preserve  it  of 
its  natural  length.  He  recovered  the  full  use 
of  the  limb  so  as  to  be  able  to  walk  without 
any  assistance,  even  that  of  a  cane.  Dr.  James, 
on  the  20th  of  December,  about  nine  months 
after  the  accident,  was  attacked  with  hasmate- 
mesis,  which  in  two  days  terminated  fatally. 
The  post-mortem  examination  of  the  right  coxo- 
femoral  articulation  shewed — 1st,  the  capsule 
a  little  thickened;  2d,  the  cotyloid  cavity 
sound ;  3d,  the  inter-articular  ligament  in  a 
natural  state;  4th,  the  neck  of  the  femur 
shortened,  from  the  bottom  of  the  head  to  the 
top  of  the  great  trochanter  was  only  four  lines, 
and  from  the  same  point  to  the  top  of  the  small 
trochanter  six  lines ;  5th,  an  unequal  line  sur- 
rounded the  neck,  denoting  the  direction  of 
the  fracture;  6th,  at  the  bottom  of  the  head  of 
the  femur  and  at  the  external  and  posterior  part 
considerable  bony  deposit  had  taken  place.  A 
section  of  the  bone  was  made  in  a  line  drawn 
from  the  centre  of  the  head  of  the  femur  to  the 
bottom  of  the  great  trochanter  so  as  perfectly 
to  expose  the  callus.  The  line  of  union  indi- 
cated by  the  callus  was  smooth  and  polished 
as  ivory.  The  line  of  callus  denoted  also  that 
the  bottom  of  the  head  of  the  femur  had  been 
broken  at  its  superior  and  posterior  part. 

Case  3. — Mr.  Stanley,  surgeon  to  St.  Bar- 
tholomew's Hospital,  in  May  1833  read  before 
the  Medico-Chirurgical  Society  of  London  a 
case  of  bony  union  of  a  fracture  of  the  neck  of 
the  thigh-bone  within  the  capsule,  occurring  in 
a  young  subject  a;t.  18.  In  the  examination  of 
the  body  of  this  young  man,  who  died  of  what 
was  considered  to  be  small-pox  about  three 
months  after  the  accident  of  the  hip-joint,  no 
other  morbid  appearances  were  discovered 
besides  those  of  the  injured  hip-joint.  The 
capsule  of  the  joint  was  entire  but  a  little 
thickened,  the  ligamentum  teres  was  uninjured, 
a  line  of  fracture  extended  obliquely  through 
the  neck  of  the  femur,  and  entirely  within  the 
capsule,  the  neck  of  the  bone  was  shortened, 
and  its  head,  in  consequence,  approximated  to 
the  trochanter  major.  The  fractured  surfaces 
were  in  the  closest  apposition  and  firmly  united, 
nearly  in  their  whole  extent,  by  bone.  There 
was  an  irregular  deposition  of  bone  upon  the 
neck  of  the  femur,  beneath  its  synovial  and 
periosteal  covering  along  the  line  of  the  fracture. 
Mr.  Stanley  adds,  "  the  foregoing  case  is  re- 
markable from  the  occurrence  of  a  fracture  of 
the  neck  of  the  femur  within  the  capsule  at  an 
early  age,  and  it  is,  I  believe,  the  only  example 
of  it  on  record." 


Sir  A.  Cooper  has  published  a  letter  in  the 
Medical  Gazette,  April  1834,  vol.  xiv.,  which 
is  intended  to  explain  his  sentiments  upon  this 
subject,  and  to  set  the  profession  in  general 
and  the  French  surgeons  in  particular  right  as 
to  the  conceptions  formed  of  the  doctrine  he 
held  as  to  the  susceptibility  of  the  bony  con- 
solidation of  the  intra-capsular  fracture.  In  it 
we  find  the  following  case. 

Case  4. — Mrs.  Powell,  aged  above  80  years, 
fell  down  in  the  afternoon  of  the  14th  of  No- 
vember, 1824.  Sir  Astley  Cooper  saw  her  soon 
after,  and  found  her  complaining  very  much  of 
pain  in  the  left  hip.  The  limb  could  be  moved 
in  every  direction,  but  this  motion  produced 
excessive  pain.  She  lay  on  her  back  with  the 
limb  extended,  and  nothing  whatever  was  done, 
except  to  apply  fomentations,  in  the  first  few  days. 
He  believed  there  was  a  fracture  of  the  neck  of 
the  thigh-bone  although  the  limb  remained 
quite  as  long  as  the  other,  and  he  could  per- 
ceive neither  a  crepitus  nor  any  altered  appear- 
ance in  its  position,  except  a  slight  inclination 
of  the  toes  outwards.  She  had  more  constitu- 
tional irritation  than  Sir  Astley  ever  observed 
from  a  similar  accident.  She  suffered  much 
pain  in  the  hip,  and  was  in  consequence  obliged 
to  take  an  opiate,  but  she  got  very  little  rest. 
She  generally  had  much  thirst.  There  was  the 
utmost  difficulty  in  keeping  her  bowels  open, 
and  she  had  great  pain  and  difficulty  in  making 
water.  She  had  no  appetite  for  common  food, 
and  for  three  weeks  appeared  so  weak  that  she 
was  under  the  necessity  of  taking  wine  and 
brandy.  For  some  time  all  her  urine  and 
stools  were  passed  in  bed,  but  not  involuntarily, 
and  only  because  she  could  not  be  persuaded 
to  use  proper  means ;  in  consequence  her  back 
became  very  sore.  Latterly  she  complained  of 
pain  in  the  abdomen,  which  was  very  tender 
on  pressure,  and  even  the  weight  of  the  bed- 
clothes was  inconvenient.  Her  tongue  became 
very  dry  and  brown,  and  the  last  twenty-four 
hours  she  was  insensible.  She  died  on  the 
morning  of  the  19th  December  about  five. 

Examination. — This  took  place  at  seven  in 
the  evening.  There  was  some  ecchymosis 
amongst  the  muscles  about  the  injured  part 
and  in  the  cellular  membrane  about  the  sciatic 
and  anterior  crural  nerves.  The  greatest  part 
of  the  fracture  of  the  neck  of  the  thigh-bone, 
which  was  entirely  within  f8e  capsular  ligament, 
was  firmly  united.  A  section  was  made  through 
the  fractured  part,  and  a  faint  white  line  was 
perceived  in  one  portion  of  the  union,  but  the 
rest  appeared  to  be  entirely  bone.  This  case,  says 
Mr.  Swan,  beautifully  shews  the  principle  which 
Sir  A.Cooper  has  advocated,  viz.  that  when  the 
reflected  ligament  remains  whole,  and  the  bones 
are  not  drawn  asunder,  the  nourishment  to  the 
head  of  the  bone  continues,  and  union  will  be 
produced  even  in  the  short  space  of  five  weeks, 
by  only  placing  the  knee  over  a  pillow,  and  in 
other  respects  leaving  the  case  to  nature. 

We  find  Mr.  Samuel  Cooper  is  of  opinion 
that  a  bony  consolidation  of  the  intra-capsular 
fracture  is  proved.    He  says,*  "  Sir  A.  Cooper 

*  Surgical  Diet.  p;  575,  last  ed. 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


813 


has  satisfied  himself  that  osseous  union  some- 
times takes  place,  and  he  has  in  his  own  col- 
lection a  most  unequivocal  specimen  of  it, 
which  he  was  kind  enough  to  show  me  two 
years  ago.  The  possibility  of  bony  union  is 
now  universally  acknowledged,  but  the  cure  in 
this  way  is  far  less  frequent  than  that  by  means 
of  a  ligamentary  connexion."* 

It  does  not  appear  to  us  that  this  question  is 
yet  so  entirely  settled  as  the  last  writer's  obser- 
vations would  lead  us  to  imagine  ;  although  in 
this  city  (Dublin)  the  subject  has  been  care- 
fully investigated  for  many  years,  we  do  not 
find  our  museums  yet  contain  a  single  speci- 
men of  the  intra-capsular  fracture  united  by 
bone.    In  Paris  we  find  Cruveilhier,  one  of 
the  most  eminent  pathologists  in  France,  ex- 
pressing himself  in  the  most  unreserved  manner, 
that  a  bony  consolidation  of  the  intra-capsular 
fracture  was  impossible.   Not  unaware,  as  must 
be  supposed,  of  the  eight  cases  referred  to  by 
his  pupil,  M.  Chassaignac,f  (amongst  which  are 
those  of  Langstaff,  Stanley,  and  Sir  A.  Cooper,) 
Cruveilhier,  to  whom  Chassaignac's  memoir  is 
dedicated,  thus  expresses  himself: — "Je  suis 
porte  a  considerer  comme  des  cas  de  deforma- 
tion de  la  tete  et  du  col,  la  plupart,  si  non  la 
totalite  desfaits,  que  Ton  invoque  gen6ralement 
pour  etablir  la  reunion  de  fractures  intia-cap- 
sulaires  du  col  du  femur,  a.  l'aide  d'un  cal  os- 
seux,  le  cal  est  impossible,  parceque  les  frag- 
menslibres,  au  milieu  de  la  synovie,  ne  sont  point 
entoures  des  tissues  charges  de  la  reparation  de 
la  solution  de  continuite."    Thus  not  content 
with  asserting  that  bony  union  is  impossible, 
lie  further  adds  that  he  is  convinced  from  nu- 
merous pathological  observations,  and  from  ex- 
periments on  animals,  that  the  ideas  of  bony 
union  by  means  of  a  first,  a  provisional  callus, 
and  then  by  means  of  a  final  callus,  are  erro- 
neous; he  is  certain  that  there  is  but  one  and 
the  same  callus,  which  passes  through  different 
stages  of  development,  until  the  ossification  is 
complete  ;  he  is  of  opinion  that  the  ends  of  the 
broken  bone,  no  matter  how  confronted  or  held 
together,  never  are  directly  united.  This  union, 
he  thinks,  can  only  take  place  through  the  in- 
tervention of  callus,  which  is  always  thrown 
round  the  bones  where  fractured,  like  a  clasp  or 
bony  ferule  ;  therefore,  he  reasons,  the  cause  of 
the  difference  between  the  intra-capsular  and 
extra-capsular  fractuffi,  with  reference  to  their 
susceptibility  of  b(my  consolidation,  is,  that  in 
the  first  the  fragments  are  as  it  were  abandoned 
to  themselves  to  effect  an  union  ;  here  there  is 
no  bony  ferule  or  clasp  possible,  while  in  the 
second  the  fragments  are  in  the  same  condition 
as  in  all  other  fractures;  that  is  to  say,  they  are 
surrounded  by  soft  parts,  by  the  ossification  of 
which  the  bony  clasp  is  formed.    Thus  does 
he  not  only  deny  the  possibility  of  bony  conso- 
lidation in  the  case  of  the  intra-capsular  fracture, 
but  endeavours  to  explain  why  the  union  is 
impracticable. 

We  cannot  agree  with  this  eminent  patholo- 
gist in  the  observations  that  the  ends  of  the 

*  Loc.  cit. 

t  De  la  Fracture  du  col  du  femur.   Par  E.  Clias- 
saignac,  M.D.,  Paris,  1835. 


bones  themselves  take  no  part  in  effecting  a 
bony  union,  for  in  cases  of  impacted  fracture 
alluded  to  by  us  in  a  preceding  article,  particu- 
larly in  the  case  of  Sherlock,  from  which 
fig.  320  has  been  taken,  bony  consolidation  had 
taken  place  in  almost  the  whole  line  of  the 
fracture,  and  could  only  have  been  effected 
by  the  union  of  the  two  bony  surfaces  which 
were  confronted  to  each  other.  No  doubt  the 
union  here  was  further  fortified  by  the  external 
effusion  of  new  callus,  which  surrounded  the 
bone  at  the  seat  of  the  fracture.  When  we  re- 
flect on  the  cases  adduced  in  proof  of  the  bony 
consolidation  of  the  intra-capsular  fracture,  we 
must  either  disbelieve  the  facts,  or  admit  that 
the  union  is  not  impossible. 

It  would  have  been  satisfactory  if  the  test  by 
boiling  the  specimens  of  the  united  fractures 
had  been  resorted  to  in  all  these  cases,  as  it  had 
been  in  Mr.  Langstaff's  ;  this  observation  par- 
ticularly applies  to  the  case  reported  by  Dr. 
Brulalour.  of  Bourdeaux.  We  find  in  Chas- 
saignac's report  of  this  same  case,  taken  from 
the  memoir  sent  to  the  Academy  of  Medicine 
of  Paris,  (Seancedu  16  Avril,  1827)  in  alluding 
to  the  specimen  in  question  he  says: — "Scie, 
dans  toute  sa  longueur  le  cal  se  presentait  sous 
la  forme  d'une  ligne  oblique,  raboteuse,  d'une 
couleur  moins  blanche  etd'un  consistence  un 
peu  moins  ferme  que  le  reste  de  l'os.'' 

We  had  thus  far  entered  into  this  much  agi- 
tated question,  when  an  interesting  opportunity 
occurred  to  us  of  making  the  post-mortem  exa- 
mination of  a  case  of  united  intra-capsular 
fracture.    The  history  of  the  case  was  this: — 

Owen  Curran,  set.  70,  was  for  the  last  five 
years  an  inmate  of  the  pauper  department  of 
the  House  of  Industry;  he  was  very  infirm  on 
his  limbs,  and  his  mind  was  in  a  state  of 
dotage;  on  the  1st  of  August,  1837,  while 
walking  across  his  ward,  he  fell  on  his  right 
side  ;  he  was  unable  to  rise,  and  complained  of 
pain  in  his  right  hip ;  he  was  carried  to  bed, 
and  was  immediately  visited  by  the  late  Mr. 
William  Johnstone,  who  was  then  acting  for 
me  as  clinical  pupil,  who  found  the  limb 
everted,  and  only  half  an  inch  shorter  than 
the  other.    Mr.  Johnstone  considered  the  case 
a  fracture  of  the  cervix  femoris,  which  required 
no  other  surgical  treatment  than  that  of  placing 
and  preserving  the  limb  in  a  semiflexed  po- 
sition over  pillows.    The  old  man  suffered  but 
little  pain  in  the  injured  part,  at  all  events  he 
did  not  complain  of  it.    In  about  five  weeks 
after  the  accident  he  was  raised  out  of  his  bed, 
and  when  placed  standing,  he  was  able  to  put 
the  heel  of  the  injured  limb  to  the  ground.  On 
the  30th  of  September,  that  is,  about  eight 
weeks  after  the  accident,  my  friend  Mr.  Smith 
entered  in  his  note-book  the  following  memo- 
randum of  this  case  : — "  As  the  patient  lies  in 
bed  he  can  elevate  the  injured  limb  by  the  un- 
assisted efforts  of  its  own  muscles.    The  ever- 
sion  is  slight,  and  the  degree  of  shortening 
amounts  to  one  inch ;  no  force  can  bring  the 
limb  down  to  the  length  of  the  other.  From 
the  history  and  symptoms,  this  seems  to  have 
been  a  case  of  impacted  fracture."    This  man 
survived  the  accident  one  year  and  nearly 


814 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


ten  months,  during  which  time  he  was  con- 
tented to  remain  most  of  the  time  in  his  bed, 
but  when  placed  on  his  feet,  could  stand  very 
well,  and  was  able  but  unwilling  to  walk.  On 
Tuesday  the  20th  of  May  he  got  an  attack  of 
bronchitis,  which,  the  following  Friday,  ter- 
minated fatally.  At  twelve  o'clock,  on  Satur- 
day, the  25th  May,  assisted  by  Mr.  Brabazon 
and  some  of  the  pupils  of  the  hospital,  I  made 
an  examination  of  the  body.  The  right  leg  and 
thigh  were  much  everted.  The  trochanter 
major  was  elevated,  and  projected  much  out- 
wards;  the  degree  of  shortening  just  amounted 
to  one  inch ;  the  muscles  presented  a  healthy 
appearance,  the  capsular  ligament  was  of  a  yel- 
lowish colour,  and  somewhat  thickened.  The 
femur  was  removed  from  the  acetabulum  ;  this 
/  latter  cavity  presented  a  healthy  appearance,  ex- 
cept towards  the  margin  of  it;  here  the  cartilage 
was  softened.    The  round  ligament  was  sound. 

The  head  and  neck  of  the  bone  had  lost  their 
normal  obliquity,  and  were  directed  nearly  ho- 
rizontally inwards  (fig.  321);  the  cervix  pre- 
sented, both  anteriorly  and  posteriorly,  evidence 
of  a  transverse  intra-capsular  fracture  having  oc- 
curred ;  the  globular-shaped  head  was  closely 
approximated  behind  and  below  to  the  posterior 
intertrochanteric  line,  and  to  the  lesser  trochan- 
ter, so  that  the  neck  seemed  altogether  lost 
except  anteriorly,  where  a  very  well-marked 
ridge  of  bone  shewed  the  seat  of  the  displace- 
ment and  of  the  union  of  the  fragments. 


This  ridge  is  evidently  the  upper  extremity  of 
the  lower  fragment  of  the  cervix.  The  fracture 
of  the  neck  posteriorly  was  found  to  have  been 
closer  to  the  corona  of  the  head  than  anteriorly, 
and  the  fibro-synovial  fold  in  the  former  situa- 
tion remained  unbroken.  A  section  has  been 
made  of  the  bone  through  the  head,  neck,  and 
trochanter  ;  one  portion  has  been  subjected  to 
maceration  and  to  boiling  ;  and  the  bony  union 
has  been  unaffected  by  these  tests.  Scarcely 
any  portion  of  the  neck  can  be  said  to  have 
been  left. 


Fig.  322. 


The  section, 322,  shews  the  compact  line 
which  denotes  the  union  of  the  fragments  ;  the 
head  and  shaft  seem  to  be  mutually  impacted 
into  each  other,  and  almost  the  whole  of  the 
cervix  has  been  absorbed  ;  the  line  of  union  is 
serrated,  solid, and  immoveable;  and  the  cells  of 
the  head  and  substance  of  the  shaft  seem  to 
communicate  freely  in  all  places,  except  where 
the  thin  line  of  compact  tissue  here  and  there 
points  out  the  seat  of  the  welding  together  of 
the  remaining  portions  of  the  head  and  neck  of 
the  femur. 

The  bone  was  in  its  recent  state,  on  the  25th 
of  May,  laid  before  a  meeting  of  the  Patho- 
logical Society.  It  seemed  to  be  the  univer- 
sal opinion  of  the  members  present  that  it 
was  a  decided  specimen  of  the  intra-capsu- 
lar fracture  of  the  cervix  femoris,  which  had 
been  solidly  united  by  bony  callus.  This  case 
may  be  adduced  in  formal  contradiction  to 
the  observation  and  theories  of  that  very  emi- 
nent pathologist,  Cruveilhier.  It  cannot  be 
said  to  invalidate  the  more  guarded  opinions 
of  Sir  A.  Cooper,  who,  in  his  observations  upon 
this  subject,  distinctly  stated  that  "  he  would 
not  be  understood  to  deny  the  possibility  of 
union,  when  the  bone  was  broken,  without  its 
periosteum  and  reflected^gament  being  torn, 
or  when  there  was  no  separation  of  its  fractured 
ends." 

Cases  such  as  the  foregoing  are  certainly 
rare,  but  they  appear  to  the  writer  to  belong  to 
the  class  of  impacted  fractures;  they  differ  from 
those  alluded  to  in  the  foregoing  article  merely 
in  this,  that  in  the  former  the  fracture  of  the 
cervix  takes  place  at  its  basis  near  the  trochan- 
ters, and  that,  in  the  latter,  the  fracture  occurs 
near  to  the  head  of  the  bone,  and  is  thus  en- 
tirely intra-capsular,  or  rather  may  be  considered 
as  fractures  of  the  intra-capsular  portion  of  the 
cervix  femoris.  The  question  then,  viz.  does 
bony  consolidation  of  the  intra-capsular  frac- 
ture of  the  cervix  femoris  ever  occur?  seems 
to  us  replied  to  in  the  affirmative. 

When  an  impaction  of  one,  or  a  mutual 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


815 


impaction  of  both  of  the  fragments  has  taken 
place,  then  under  such  peculiar  circumstances 
a  firm  bony  consolidation  of  the  fragments  may 
be  expected. 

Finally,  although  this  is  not  the  place  to 
speak  of  the  surgical  treatment  of  such  cases, 
we  may  remark  that  the  most  valuable  practical 
information,  in  our  mind,  derivable  from  the 
discovery  of  facts  like  the  foregoing,  is  that  the 
lenient  method  of  treatment,  viz.  by  position 
alone,  and  without  splints,  may  be  eminently 
successful,  so  far  as  the  accomplishment  of  a 
firm  reunion  of  the  fragments  is  concerned. 

II.  Luxations. — Luxations  of  the  head  of  the 
femur  from  the  acetabulum  are  by  no  means  so 
frequent  as  fractures  of  the  bones  which  enter 
into  the  composition  of  the  hip-joint. 

This  comparative  immunity  from  this  form 
of  accident  arises  from  these  circumstances, — 
that  the  acetabulum  which  lodges  the  head  of 
the  femur  has  great  depth,  and  that  the  fibrous 
membranes  which  secure  this  bone  in  the  coty- 
loid cavity  have  great  strength,  and  restrain 
within  certain  limits  its  movements.  Indepen- 
dently, however,  of  congenital  luxations,  and 
of  those  which  are  the  result  of  disease,  there 
are  six  distinct  forms  of  dislocation  of  the  hip- 
joint  to  be  described  as  the  result  of  accident 
alone. 

The  dislocations  of  the  head  of  the  femur  from 
accident  may  be  classed  as  follows: — a.  dislo- 
cation upwards  and  backwards  on  the  dorsum 
ilii ;  b.  directly  backwards  towards  the  ischiatic 
notch ;  c.  downwards  and  inwards  into  the 
foramen  ovale ;  d.  upwards,  forwards,  and  in- 
wards on  the  horizontal  ramus  of  the  pubes. 
Besides  these,  of  late  years  two  more  unusual 
luxations  have  been  described  and  verified  by 
post-moitem  examinations,  viz.  dislocation 
downwards  towards  the  tuberosity  of  the 
ischium,  and  dislocation  upwards  between  the 
anterior  inferior  spine  of  the  ilium  and  the  ilio- 
pubal  eminence. 

a.  Dislocation  of  the  head  of  the  t  femur 
upwards  and  backwards  on  the  dorsum,  of 
the  ilium. — When  the  head  of  the  thigh-bone 
is  thrown  on  the  dorsum  ilii,  the  limb  on  the 
luxated  side  is  from  one  to  two  inches 
shorter  than  the  other ;  the  thigh  is  slightly 
flexed,  or  a  little  advanced  upon  the  other,  and 
carried  into  a  slate  of  abduction,  and  of  marked 
rotation  inwards.  The.  patella  and  inner  side 
of  the  dislocated  limb  look  directly  inwards, 
and  the  great  toe  corresponds  to  the  tarsus  of 
the  opposite  foot.  The  great  trochanter,  carried 
forwards  and  upwards,  approaches  the  crest  of 
the  ilium  and  its  anterior  and  superior  spine, 
and  forms  there  a  very  well  marked  tumour; 
the  nates  raised  up  by  the  head  of  the  femur  is 
very  salient  towards  its  superior  and  posterior 
part.  If  we  make  attempts  to  bring  the  limb 
backwards  into  a  state  of  extension  or  abduc- 
tion or  of  rotation  outwards,  we  find  we  give 
much  pain  to  the  patient,  and  that  we  cannot 
move  the  bone  in  any  of  these  directions.  We 
can,  without  causing  suffering  to  the  patient, 
augment  a  little  the  flexion  towards  the  abdo- 
men, and  adduct  the  dislocated  thigh,  and  we 
can  also  increase  the  rotation  inwards  already 


existing,  or,  to  use  the  words  of  Sir  A.  Cooper, 
"  when  the  leg  is  attempted  to  be  separated 
from  the  other  it  cannot  be  accomplished,  as 
the  limb  is  firmly  fixed  in  its  new  situation,  so 
far  as  regards  its  motion  outwards.  The  thigh 
can  be  slightly  bent  across  the  other  and  towards 
the  abdomen,  but  extension  of  the  thigh  and 
rotation  outwards  are  impossible."  Rotation 
inwards,  on  the  contrary,  is  to  a  great  extent 
permitted,  so  much  so  indeed  that  we  have 
seen  the  back  part  of  the  heel  turned  forwards, 
while  the  toes  pointed  backwards.  During 
these  extreme  motions  of  rotation  inwards,  if 
the  hand  be  pressed  on  the  dorsum  of  the 
ilium  deeply,  the  head  of  the  femur  will  be 
perceived  to  roll  on  the  ilium,  and  its  tro- 
chanter major  also  can  at  this  time  be  felt  to 
be  nearer  than  natural  to  the  anterior  superior 
spinous  process  of  the  ilium  ;  the  trochanter  is 
less  prominent  than  that  on  the  opposite  side, 
for  the  neck  of  the  bone  and  the  trochanter  are 
resting  in  the  line  of  the  surface  of  the  dorsum 
ilii.  Upon  a  comparison  of  the  two  hips,  the 
roundness  of  the  dislocated  side  will  be  found 
to  have  disappeared.  A  surgeon,  then,  called 
to  a  severe  and  recent  injury  of  the  hip-joint, 
looks  for  a  difference  in  length,  change  of  posi- 
tion inwards,  diminution  of  motion,  and  de- 
creased projection  of  the  trochanter. 

The  explanation  of  the  manner  in  which  the 
dislocation  of  the  head  of  the  femur  upwards 
and  backwards  on  the  dorsum  ilii  takes  place 
has  been  the  subject  of  some  difference  of  sen- 
timent. The  late  Mr. Todd  has,  in  ouropinion, 
given  some  judicious  observations  on  this  sub- 
ject ; *  he  says,  "  the  elementary  work  on  luxa- 
tions most  generally  read  and  referred  to  in 
this  country,  is  Dr.  Farrell's  translation  of 
Boyer's  Lectures,  arranged  by  Richerand.  The 
following  is  the  description  therein  given  of  the 
manner  in  which  the  luxation  of  the  femur,  at 
present  under  consideration,  is  produced. 

"  When  by  a  fall  from  a  place,  more  or 
less  elevated,  on  the  soles  of  the  feet,  or  on 
the  knees,  the  thigh  is  pushed  forwards  and 
inwards,  the  head  of  the  femur,  forced  to- 
wards the  superior  and  external  part  of  the 
acetabulum,  breaks  the  internal  and  orbicular 
ligaments,  escapes  through  the  laceration  in 
the  latter,  and  ascends  on  the  external  face  of 
the  os  ilium  ;  but  as  the  part  of  the  os  ilium 
immediately  above  and  at  the  external  side  of 
the  cavity  is  very  convex,  the  head  of  the 
femur  soon  abandons  its  first  position,  and 
slides  backwards  and  upwards  into  the  ex- 
ternal fossa  of  the  os  ilium,  following  the  in- 
clination of  the  plane  towards  the  fossa,  and 
obeying  the  action  of  the  glutsei  muscles, 
which  draw  it  in  this  direction.  The  head 
of  the  femur,  in  ascending  thus  on  the  ex- 
ternal face  of  the  os  ilium,  pushes  upwards 
the  glutaeus  minimus,  which  forms  a  sort  of 
cap  for  it,  and  the  glutaeus  maximus  and  me- 
dius  are  relaxed  by  the  approximation  of  the 
points  into  which  they  are  inserted.  The  pyri- 
formis  is  nearly  in  its  natural  state;  the  gemini, 
obturatores,  and  quadratus  femoris  are  a  little 

*  Dublin  Hospital  Reports,  vol.  iii.  p.  397. 


816 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


elongated.  The  psoas  magnus  and  iliacus  in- 
ternus  are  relaxed,  as  are  also  tlie  other  muscles 
inserted  into  the  trochanter  minor."* 

From  the  foregoing  opinions  Mr.  Todd  dis- 
sents in  the  following  words  : — "  To  admit  of 
the  head  of  the  femur  being  '  forced  towards 
the  superior  and  external  part  of  the  aceta- 
balum,'  and  of  its  ascending  '  on  the  external 
face  of  the  os  ilium,'  it  will  be  obvious  to 
those  who  carefully  examine  the  mechanism  of 
the  articulation,  that  the  thigh  must  be  ex- 
tended on  the  trunk,  and  the  dislocating  force 
applied  externally  and  inferiorly,  so  as  to  pro- 
duce what  may  be  termed  an  excess  of  ad- 
duction. To  the  limb  assuming  such  positions, 
which  appear  to  me  to  be  quite  essential  to- 
wards the  production  of  this  dislocation  in  the 
manner  described  by  Bayer,  some  considerable 
obstacles  exist.  In  the  first  place,  I  believe  it 
seldom  happens  that  a  person  who  falls  from  a 
height  will  reach  the  ground  with  the  thigh 
extended  on  the  trunk ;  in  the  descent  the 
superior  power  of  the  flexor  muscles  will  pre- 
dominate, and  at  the  moment  of  the  appli- 
cation of  force  to  the  limb  it  will  be  more  or 
less  in  a  bent  position.  It  is  scarcely  neces- 
sary to  observe  that  this  circumstance  must 
materially  influence  the  direction  in  which  the 
head  of  the  bone  will  be  protruded  from  the 
articulating  cavity. 

"  Secondly,  should  the  thigh  and  leg  be  com- 
pletely extended  at  the  time  that  the  force  is 
applied,  it  is  probable  that  the  other  limb  will 
be  extended  also,  and  will  thus  prevent  a  move- 
ment of  the  stricken  limb  inwards  beyond  a 
certain  point ;  or,  in  other  words,  the  opposite 
limb  will  prevent  that  extent  of  adduction 
inferiorly  which  is  necessary  to  remove  the 
head  of  the  femur  from  the  acetabulum,  and  to 
admit  of  its  being  forced  upon  the  anterior 
convex  surface  of  the  dorsum  ilii.  But  whether 
the  opposite  limb  be  extended  or  not,  it  must 
oppose  a  certain  limit  to  adduction,  if  that 
term  can  be  applied  with  propriety  to  a 
lateral  movement  of  the  lower  extremity,  by 
■which  it  is  carried  beyond  the  middle  line  of 
the  body. 

"  Sir  Astley  Cooper  attributes  this  direction 
of  the  limb  to  the  circumstance  of  the  injury 
being  inflicted  when  the  knee  and  foot  are 
actually  turned  inwards ;  however,  it  appears 
to  me  that  muscular  action  is  also  in  favour  of 
the  limb  assuming  this  position. 

"  If  it  be  admitted  that  the  thigh  is  generally 
in  a  state  of  demiflexion  when  the  force  causing 
this  dislocation  is  applied,  it  must  also  be  ad- 
mitted that  in  this  state  the  pyriformis,  ob- 
turatores,  and  gemini  have  but  little  effect  as 
rotators,  the  power  of  these  muscles  as  such 
being  greater  or  less,  according  as  the  junction 
of  their  fibres  with  the  femur  approaches 
or  deviates  from  a  right  angle ;  and  that  the 
power  of  the  anterior  portion  of  the  glutaeus 
medius  and  of  the  tensor  fasciae  lata?,  as 
rotators  inwards,  is  increased  in  this  position, 
the  angle  which  their  fibres  form  with  the 
thigh-bone  being  augmented  ;   thus  the  last- 

*  Lectures  of  Boyer,  p.  156. 


mentioned  muscles  will  appear  to  possess 
much  influence  in  determining  the  inverted  po- 
sition of  the  limb,  as  they  must  draw  forwards 
the  trochanter  major  and  external  side  of  the 
thigh,  at  the  moment  in  which  the  head  of  the 
bone  escapes  from  the  acetabulum. 

"  The  inclination  of  the  thigh  forwards  and 
inwards  which  constitutes  so  remarkable  a  fea- 
ture of  this  dislocation,  may  be  attributed 
partly  to  the  tension  of  the  psoas  magnus,  the 
iliacus  internus,  and  the  pectinalis,  and  also 
to  the  peculiar  form  of  the  surface  of  the 
pelvis,  to  which  the  upper  part  of  the  femur 
is  applied  ;  but  certainly  not  as  Mr.  Samuel 
Cooper  has  asserted,  to  the  tense  state  of  the 
triceps  and  gracilis,  for  these  muscles  are  re- 
laxed." 

Anatomical  characters  of  the  taxation  (if  the 
head  of  the  thigh-bone  on  the  dorsum  ilii. — The 
appearances  which  have  been  noticed  in  the 
anatomical  examination  of  the  hip-joints  of 
individuals  who,  having  had  a  luxation  of  this 
articulation,  have  died  very  soon  afterwards 
of  other  severe  injuries  received  at  the  same 
time,  may  be  collected  from  the  study  of  some 
facts  of  this  nature  already  published.  Of 
these  none  gives  us  a  better  idea  of  the  recent 
effects  of  a  dislocation  upwards  and  backwards- 
on  the  dorsum  ilii  than  the  case  related  by  the 
late  Mr.  Todd,  in  the  third  volume  of  the  Dub- 
lin Hospital  Reports,  which  is  as  follows  : — 

Case. — In  the  summer  of  1818,  a  robust 
man,  in  attempting  to  escape  from  his  bed- 
room window  in  the  second  floor  of  a  lofty 
house,  fell  into  a  flagged  area,  by  which  acci- 
dent his  cranium  was  fractured,  and  his  left 
thigh  dislocated  upwards  and  backwards. 

The  dislocation  was  reduced  without  diffi- 
culty ;  however,  an  extensive  extravasation  of 
blood  having  taken  place  on  the  brain,  the 
patient  lingered  in  a  comatose  state  for  about 
twenty-four  hours,  and  then  died.  On  the 
day  after  dissection  was  performed,  and  the 
following  appearances  were  observed  in  the  in- 
jured joint  and  the  parts  contiguous  to  it. 

On  raising  the  glutaeus  maximus,  a  large 
cavity  filled  with  coagulated  blood  was  found 
between  that  muscle  and  the  posterior  part  of 
the  glutaeus  medius.  This  was  the  situation 
which  had  been  occupied  by  the  dislocated 
extremity  of  the  femur.  The  gluteus  medius 
and  minimus  were  uninjured.  The  pyriformis, 
gemini,  obturatores,  and  quadratus  were  com- 
pletely torn  across.  Some  fibres  of  the  pec- 
tinalis were  also  torn.  The  iliacus,  psoas,  and 
adductors  were  uninjured.  The  orbicular  liga- 
ment was  entire  at  the  superior  and  anterior 
part  only,  and  it  was  irregularly  lacerated 
throughout  the  remainder  of  its  extent.  The 
inter-articular  ligament  was  torn  out  of  the  de- 
pression on  the  head  of  the  femur,  its  attach- 
ment to  the  acetabulum  remaining  perfect. 
The  bones  had  not  sustained  any  injury. 

Cruveilhier,  in  the  28th  and  29th  livraisons 
of  his  valuable  work  on  Pathological  Anatomy, 
has  given  two  cases  of  what  he  considers  to  be 
old  luxations  of  the  head  of  the  femur  up- 
wards and  outwards  on  the  dorsum  ilii,  which 
had  been  left  unreduced  ;  the  history  of  these 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


817 


cases  was  unknown.  When  we  carefully  ex- 
amine the  author's  account  of  them,  and  refer 
to  the  eight  accompanying  drawings  he  has 
given  of  them,  doubts  may  well  arise  in  the 
mind  as  to  whether  these  are  to  be  considered 
congenital  luxations,  or  the  result  of  accidents 
which  had  occurred  after  birth.  The  author 
does  not  himself  seem  free  from  suspicion  on 
this  matter,  for,  in  commencing  his  observa- 
tions on  the  pathological  anatomy  of  cases  of 
luxation  of  the  femur  on  the  dorsum  ilii, 
upwards  and  outwards,  he  says,  "  elles  sont 
tantot  congeniales,  tantot  posterieurs  a  la  nais- 
sance.  Existe-t-il  des  differences  notables 
entre  les  unes  et  les  autres  sous  le  point  de 
l'anatomie  pathologique  ?  II  m'est  permis 
d'en  douter  jusqu'a  ce  que  des  faits  positifs 
aientetabli  le  contraire."  We  have  in  some  of 
the  preceding  pages  adduced  what  we  have 
considered  positive  proofs  that  the  anatomical 
characters  of  the  congenital  luxation  of  the  hip- 
joint  are  altogether  peculiar,  and  the  appearances 
either  in  the  living  or  the  dead  are  in  our 
opinion  by  no  means  to  be  confounded  with 
those  which  are  the  result  of  luxations  which 
have  occurred  after  birth,  and  have  been  left 
unreduced. 

When  opportunities  have  occurred  of  exa- 
mining the  hip-joints  of  those  who  have  for 
many  years  survived  a  dislocation  of  the  head 
of  the  femur  upwards  and  backwards  on  the 
dorsum  ilii,  and  which  had  been  left  unre- 
duced, remarkable  changes  have  been  noticed 
to  have  taken  place  in  the  bones  and  surround- 
ing structures. 

Muscles. — The  muscles  of  the  dislocated  hip 
have  been  found  for  the  most  part  in  a  state 
of  comparative  atrophy,  and  the  direction  of 
their  fibres  has  of  course  been  altered  by  the 
ascent  of  the  superior  extremity  of  the  femur. 
Among  the  muscles  of  the  hip-joint  the  con- 
dition of  the  gluteus  minimus  has  been  most 
dwelt  on  by  authors. 

It  is  stated  on  the  respectable  authority  of 
Boyer,  that  when  the  head  of  the  femur  is 
dislocated  upwards  and  backwards  on  the 
dorsum  ilii,  it  passes  between  the  external 
iliac  fossa,  and  the  little  gluteus ;  that  it 
carries  this  muscle  up,  and  is  as  it  were 
capped  by  it  ("  pour  ainsi  dire  coiffee").  This 
muscle,  he  elsewhere  adds,  envelopes  imme- 
diately the  head  of  the  femur  ;  it  undergoes 
very  remarkable  changes ;  it  becomes  pale ; 
■its  fibres  disappear  almost  entirely,  and  are 
changed  into  a  fibrous  substance  which  is  firm 
and  solid,  and  which  has  been  sometimes  seen 
converted  into  bone.  Cruveilhier  seems  to  have 
adopted  Boyer's  idea  as  to  the  change  this 
muscle  undergoes  in  these  cases.  But  if  it  be 
true,  as  we  believe  it  is,  that  at  the  moment 
the  luxation  we  are  now  considering  occurs, 
the  limb  is  in  a  state  of  semiflexion,  we 
shall  find  it  difficult  to  conceive  how  the  head 
of  the  bone  in  passing  can  encounter  any  of 
the  fibres  of  the  glutaeus  medius  or  minimus, 
except  it  be  the  most  posterior  and  inferior  of 
them. 

Mr,  Wallace  has,  in   the  Transactions  of 

VOL.  II. 


the  College  of  Physicians  in  Ireland,*  given 
a  very  minute  and  valuable  account  of  a  case 
of  dislocation  of  the  head  of  the  femur  on  the 
dorsum  ilii.  The  history  of  the  case  was  un- 
known ;  but  the  state  of  the  parts  engaged  left 
no  doubt  on  his  mind  that  it  must  have  been 
many  years  since  the  bone  had  been  dislocated, 
and  from  the  appearance  of  the  body  he  con- 
cluded that  the  subject  was  not  less  than  fifty. 
The  glutei  muscles  were  in  a  state  approach- 
ing to  that  of  atrophy  :  the  posterior  edge  of 
the  glutaeus  medius  ran  exactly  over  the  head 
of  the  femur;  the  texture  of  the  gluteus  mini- 
mus resembled  adeps  more  than  healthy  mus- 
cular fibre. 

The  pyriformis  did  not  extend  to  the  tro- 
chanter major,  but  terminated  at  the  distance 
of  some  inches  from  this  process,  in  the  new 
capsule  which  covered  the  head  of  the  femur. 
There  was  not  a  trace  of  the  obturator  internus, 
its  place  having  been  occupied  by  a  quantity  of 
fat  of  a  peculiarly  gristly  texture  ;  the  quadratus 
and  gemelli  were  pale  and  small,  and  were 
bisected  by  an  irregular  tendinous  line.  The 
direction  of  these  muscles  between  their  points 
of  attachment  was  more  oblique  than  natural ; 
the  psoas  and  iliacus  were  diminished  in  size, 
and  their  line  of  direction  from  the  brim  of  the 
pelvis  to  their  connexion  with  the  lesser  tro- 
chanter was  altered,  as  was  also  the  direction 
of  the  triceps,  pectinales,  and  obturator  exter- 
nus,  all  which  were  carried  upwards  above  the 
level  of  their  usual  course  by  the  elevation  of  the 
upper  extremity  of  the  femur  on  the  dorsum  ilii. 

The  femoral  vessels  and  nerves  having  passed 
under  Poupart's  ligament,  were  sunk  into  a 
deep  fossa,  and  extended  backwards  and  out- 
wards until  they  approached  the  lesser  trochan- 
ter; they  ran  more  in  a  serpentine  or  tortuous 
course  than  the  corresponding  vessels  of  the 
opposite  limb ;  the  sciatic  nerve  was  flattened, 
its  direction  curved,  and  its  vessels  were  vari- 
cose. Its  entire  structure  appeared  as  if  it  had 
been  the  seat  of  chronic  inflammation. 

Ligaments. — In  this  case  a  very  strong  liga- 
mentous fasciculus  extended  below  the  anterior 
and  lower  part  of  the  llio-pubic  eminence 
and  the  lesser  trochanter;  this  must  have  per- 
formed the  function  of  a  check  ligament  to  the 
motion  of  eversion,  for  any  attempt  at  turning 
the  limb  outwards  rendered  this  ligament  very 
tense.  A  thick  capsule  surrounded  the  new 
articulating  surface  of  the  ilium,  and  also  the 
head  and  neck  of  the  femur;  although  the  inner 
surface  of  this  was  smeared  with  synovia,  it 
had  not  the  smooth  aspect  of  an  original  syno- 
vial membrane.  There  was  imbedded  in  the 
capsule  a  piece  of  bone  of  a  rounded  figure, 
half  an  inch  in  diameter.f  There  were  no  re- 
mains of  round  ligament. 

Hones. — The  great  trochanter  was  thrown 
forwards  with  respect  to  the  head  of  the  bone  : 
the  anterior  internal  and  inferior  portion  of  the 
head  of  the  femur  was  applied  to  the  dorsum 
ilii,  and  there  was  an  articulating  surface  worn 

*  Vol.  V.  p.  252. 

t  Mr.  W.  imagined  this  to  be  a  portion  of  the 
acetabulum. 

3  H 


818 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


on  the  head  of  the  femur,  which  marked  its 
point  of  contact  with  the  os  innominatum :  the 
articulating  surface  thus  formed  on  the  head  of 
the  femur  was  very  slightly  convex,  about  one 
inch  and  a  half  in  diameter,  smooth,  whitish, 
hard,  and  polished,  though  not  uniformly  so  ; 
for  in  some  parts  the  bone  appeared  red  and 
porous ;  the  remaining  portion  of  the  head  of 
the  femur  was  not  opposed  to  bone,  but  applied 
to  the  capsule  which  surrounded  the  joint ;  the 
head  had  lost  its  natural  rounded  form,  was  very 
irregular,  and  deprived  of  its  cartilage,  but 
some  parts  of  it  were  covered  by  a  substance 
of  the  nature  of  ligament.  There  were  several 
small  pits  on  the  head  of  the  femur,  but  none 
of  them  appeared  to  have  been  the  depression 
for  the  attachment  of  the  round  ligament. 
There  was  an  irregular  ossific  deposit  round 
the  lesser  trochanter. 

The  surface  of  the  ilium,  to  which  the  head 
of  the  bone  was  applied,  was  elevated  half  an 
inch  above  the  level  of  the  surrounding  bone, 
so  that  this  cavity  appeared  to  have  been  formed 
upon  a  plate  of  bone  which  had  been  planted, 
as  it  were,  on  the  ilium.  The  superior  and 
posterior  portion  of  the  new  acetabulum,  or 
about  two-thirds  of  its  whole  extent,  was 
smooth  and  polished,  and  presented  a  suitable 
corresponding  surface  to  receive  the  head  of  the 
femur  ;  the  aspect  of  the  articulating  surface  on 
the  ilium  was  backwards,  outwards,  and  up- 
wards. There  was  scarcely  a  vestige  of  the  old 
acetabulum  in  its  site ;  there  was  a  superficial 
fossa,  of  a  triangular  form,  filled  with  a  fibrous 
substance,  continuous  with  a  surrounding  cel- 
lular tissue.  There  was  no  articular  cartilage 
on  any  portion  of  the  bones  which  formed  the 
new  joint.  There  was  a  deep  groove,  one  inch 
in  depth,  formed  on  the  outer  side  of  the  ilio- 
pubic symphysis,  for  the  lodgement  of  the  con- 
joined tendons  of  the  psoas  and  iliacus  muscles 
in  their  passage  over  the  brim  of  the  pelvis  to 
the  lesser  trochanter. 

The  pelvis,  in  this  case,  was  much  elevated 
on  the  side  corresponding  to  the  luxation. 

b.  Lupatio/i  backwards  or  towards  the  ischia- 
tic notch. — The  space  which  is  called  the 
ischiatic  notch  is  bounded  above  and  anteriorly 
by  the  ilium,  posteriorly  by  the  sacrum,  and  in- 
feriorly  by  the  sacro-sciatic  ligament  (Jig.  323). 
It  is  formed  forgiving  passage  to  the  pyriformis 
muscle  and  to  the  sciatic  nerve,  as  well  as  to  the 
great  arteries,  the  gluteal,  ischiatic,  and  internal 
pudendal.  Its  situation,  with  respect  to  the 
acetabulum  in  the  natural  position  of  the  pelvis, 
is  a  little  above  its  level,  and  it  is  also  placed 
behind  it ;  when  the  head  of  the  bone  is  thrown 
into  this  space,  it  is  placed  backwards  and  up- 
wards with  respect  to  the  acetabulum.  Therefore 
though  called  the  dislocation  backwards,  it  is 
to  be  remembered  that  it  is  a  dislocation  back- 
wards and  a  little  upwards. 

In  this  dislocation  the  head  of  the  thigh-bone 
is  placed  on  the  pyriformis  muscle,  between  the 
edge  of  the  bone  which  forms  the  upper  part  of 
the  ischiatic  notch  and  the  sacro-sciatic  liga- 
ments, behind  the  acetabulum,  and  a  little  above 
the  level  of  the  middle  of  that  cavity. 


Fig.  323. 


1,  Pyriformis;  2,  lesser  sacro-sciatic  ligament; 
3,  gemellus  superior ;  4,  obturator  internum ;  5,  ge- 
mellus inferior  ;  6,  tuber  ischii. 


It  is  the  dislocation  most  difficult  both  to 
detect  and  to  reduce ;  to  detect,  because  the 
length  of  the  limb  differs  but  little,  and  its  po- 
sition is  not  much  changed  as  regards  the  knee 
and  foot,  as  in  the  dislocation  upwards ;  to  re- 
duce, because  the  head  of  the  bone  is  placed 
deep  behind  the  acetabulum,  and  it  therefore 
requires  to  be  lifted  over  its  edge,  as  well  as  to 
be  drawn  towards  its  socket. 

The  signs  of  this  dislocation  are,  that  the 
limb  is  about  half  an  inch  shorter  than  the 
other,  but  generally  not  more  than  half  an  inch  ; 
that  the  trochanter  major  is  behind  its  usual 
place,  but  still  remains  nearly  at  right  an- 
gles with  the  ilium,  with  a  slight  inclination 
towards  the  acetabulum  ;  the  head  of  the  bone 
is  so  buried  in  the  ischiatic  notch  that  it  cannot 
be  distinctly  felt,  except  in  thin  persons,  and 
then  only  by  rolling  the  thigh-bone  forwards, 
as  far  as  the  comparatively  fixed  state  of  the 
limb  will  allow.  The  knee  and  the  foot  are 
turned  inwards,  but  not  so  much  as  in  the  dis- 
location upwards,  and  the  toe  rests  against  the 
ball  of  the  great  toe  of  the  other  foot.  When 
the  patient  is  standing,  the  toe  touches  the 
ground,  but  the  heel  does  not  quite  reach  it ; 
the  knee  is  not  so  much  advanced  as  in  the 
dislocation  on  the  dorsum  ilii,  but  is  still 
brought  a  little  more  forwards  than  the  other, 
and  is  slightly  bent.  The  limb  is  fixed,  so  that 
flexion  and  rotation  are  in  a  great  degree  pre- 
vented. 

The  following  case  of  dislocation  backwards 
towards  the  ischiatic  notch  affords  us  a  good 
example  of  this  accident.  John  Magee,  set.  54, 
a  strong  muscular  labourer,  was  admitted  into 
Jervis-street  Infirmary,  lOthof  November,1831, 
under  my  care,  in  consequence  of  his  having 
been  severely  injured  in  his  left  hip.  He  stated 
that  while  carrying  on  his  back  a  sack  of  pota- 
toes, (about  3  cwt.)  he  unfortunately  placed  his 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


819 


foot  upon  a  round  stone,  which  rolled  from 
under  him,  and  he  came  down  with  consider- 
able violence  on  his  left  knee  and  side ;  when 
raised,  he  was  incapable  of  walking,  and  was 
immediately  carried  to  hospital.  The  follow- 
ing morning,  on  examination,  we  made  the  fol- 
lowing observations  :  while  standing,  the  body 
was  bent  forwards,  inclining  towards  the  left  or 
affected  side ;  the  left  knee  and  foot  were 
turned  inwards  ;  the  knee  somewhat  more  ad- 
vanced and  higher  than  the  other,  half  flexed, 
and  the  toes  were  resting  on  the  ball  of  the 
great  toe  of  the  opposite  foot ;  posteriorly,  the 
natis  was  prominent,  and  its  lower  fold  was 
obliterated  ;  the  distance  between  the  anterior 
superior  spinous  process  of  the  ilium  and  tro- 
chanter major  was  less  by  one  inch  than  be- 
tween the  same  points  on  the  unaffected  side  ; 
the  head  of  the  bone  could  not  be  distinctly 
felt ;  the  limb  could  be  drawn  inwards  across 
the  opposite  thigh,  but  any  attempt  to  move  it 
in  the  contrary  direction  was  productive  of 
considerable  pain ;  he  complained  of  much 
uneasiness  in  the  groin  (which  was  attributed 
to  the  tense  state  of  the  muscles  inserted  into 
the  trochanter  minor)  ;  the  patient  complained 
greatly  of  numbness  extending  along  the  poste- 
rior and  outer  part  of  the  thigh  and  leg  to  the 
foot.  The  bone  was,  in  this  case,  easily  re- 
duced, not,  however,  without  the  assistance  of 
the  pulleys. 

This  dislocation  is  improperly  denominated 
by  some,  luxation  downwards  and  backwards. 
Some  surgeons,  on  the  other  hand,  describe 
cases  of  this  accident,  and  yet  name  them  dis- 
location upwards  and  backwards  on  the  dor- 
sum ilii.  Of  this  class,  is  an  interesting  ex- 
ample published  by  the  late  Dr.  Scott,  of  the 
Armagh  Infirmary,  in  the  third  volume  of  the 
Dublin  Hospital  Reports.  The  man,  the  sub- 
ject of  the  accident,  died  thirty-six  hours  after 
the  injury. 

Dr.  Scott  says : — "  When  the  patient  was 
lifted  out  of  bed  and  placed  erect,  the  limb 
retained  the  posture  before  described  ;  it  was 
nearly  two  inches  shorter  than  the  other;  the 
knee  rested  above  its  fellow  ;  the  toes  were 
turned  inwards,  and  lay  above  the  opposite 
instep.  On  viewing  the  hip,  the  trochanter 
was  manifestly  higher  on  the  maimed  side  than 
the  other.  The  hollow  naturally  formed  behind 
that  process  had  disappeared — the  buttock  was 
shorter  and  rounder,  but  flaccid  ;  the  head  of 
the  bone  could  not  be  felt  through  the  glutaei 
muscles.  No  effort  of  the  patient  could  extend 
the  limb,  but  he  had  the  power  of  bending  it  a 
little  towards  the  abdomen,  by  making  the  op- 
posite leg  a  fulcrum  for  the  inverted  toes  to 
creep  upwards  upon.  The  dislocation  was  re- 
duced, and  he  died  in  thirty-six  hours  after- 
wards, in  consequence  of  the  injury  some  of 
the  organs  in  the  abdomen  received,  at  the  same 
time  that  the  hip-joint  was  dislocated."  It  is 
stated,  that "  on  dissecting  down  to  the  hip-joint, 
an  extensive  extravasation  of  blood  presented 
itself  in  the  cutaneous  cellular  membrane,  co- 
vering the  trochanter  major,  and  also  beneath 
the  fascia  lata  of  the  thigh,  extending  several 


inches  above  and  below  the  trochanter.  The 
gluteus  magnus  being  raised  from  its  origin,  a 
considerable  extravasation  was  found  in  the 
loose  cellular  tissue  under  the  gluteus  medius. 
A  cavity  capable  of  containing  a  pullet's  egg 
was  also  brought  into  view.  This  cavity  was 
situated  directly  where  the  great  sciatic  nerve 
passes  under  the  pyrifbrm  muscle;  it  contained 
fluid  blood  ;  its  boundaries  were  the  pyriformis 
above,  the  sciatic  nerve  before  (supposing  the 
body  upright),  the  trochanter  major,  and  insertion 
of  the  gluteus  medius  external  and  posterior ; 
the  gluteus  maximus  directly  posterior.  Here 
the  displaced  head  of  the  femur  had  been 
lodged.  The  fleshy  substance  of  the  gemelli 
and  quadratus  muscles  was  found  torn  across. 
The  pyriformis  and  obturator  internus  were 
perfect;  the  extravasated  blood  followed  the 
course  of  the  sciatic  nerve  deep  into  the  thigh  ; 
there  was  also  extravasation  between  the 
gluteus  medius  and  minimus  muscles.  The 
internal  and  upper  part  of  the  capsular  liga- 
ment of  the  joint  was  ruptured;  the  external 
portion  remained  unbroken.  On  turning  the 
head  of  the  bone  out  of  its  socket,  the  liga- 
mentum  teres  was  found  to  have  been  torn  from 
its  insertion  into  the  dimple  of  the  head  of  the 
thigh-bone  ;  the  brim  of  the  acetabulum,  at  its 
upper  part,  was  fractured  to  the  extent  of  about 
one  inch ;  the  fractured  portion  lay  loose  and 
nearly  unconnected  ;  a  fracture  traversed  the 
acetabulum."  In  this  case  it  is  manifest,  from 
the  dissection,  that  the  head  of  the  bone  lay 
beneath  even  the  level  of  the  lower  edge  of  the 
pyriform  muscle,  as  Dr.  Scott  states  that  the 
boundaries  of  the  cavity  (capable  of  containing 
a  pullet's  egg,  and  rilled  with  coagulated 
blood,)  which  no  doubt  was  the  new  situation 
that  the  head  of  the  dislocated  femur  for  a  time 
rested  in, — that  the  boundaries  of  this  cavity 
were  "  the  pyriformis  above,"  &c.  The  dis- 
section we  consider  a  valuable  one,  adding 
something  to  our  knowledge  of  the  anatomical 
characters  of  the  luxation  into  the  ischiatic 
notch  ;  differing,  however,  in  some  few  particu- 
lars, from  that  of  Sir  A.  Cooper,  Dr.  Scott's,  it 
is  to  be  recollected,  was  the  dissection  of  a  case 
in  which  the  bone  had  been  only  a  few  hours 
misplaced.  When  we  analyse  the  previous 
symptoms  of  Dr.  Scott's  case,  we  do  not,  it 
must  be  confessed,  read  the  characteristic  fea- 
tures detailed  of  the  dislocation  backwards  ; 
still  the  pain  the  patient  suffered  along  the 
course  of  the  sciatic  nerve  rather  pointed  the 
attention  to  a  dislocation  on  the  sciatic  notch, 
than  to  the  ordinary  one  of  dislocation  upwards 
on  the  dorsum  ilii,  in  which  the  nerve  is 
not,  at  least  directly,  interfered  with;  and  the 
observation  added,  that  "  the  head  of  the  bone 
could  not  be  felt  through  the  glutei  muscles," 
also  would  lead  us  to  infer  that  among  many 
of  the  symptoms  this  patient  laboured  under, 
some  were  such  as  would  lead  us  to  suspect 
that  the  luxation  was  that  backwards  towards 
the  sciatic  notch,  a  suspicion  that,  in  the  wri- 
ter's mind,  the  dissection  given  by  Dr.  Scott 
would  fully  justify. 

We  suspect,  also,  that  one  of  the  cases 
3  H  2 


820 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


published  by  Mr.  Bransby  Cooper*  as  one 
of  dislocation  on  the  dorsum  llii,  was  ra- 
ther the  dislocation  we  are  now  considering, 
namely,  the  luxation  towards  the  ischiatic 
notch.  Among  some  of  this  patient's  symp- 
toms, it  is  mentioned  that  the  trochanter  major 
was  plainly  felt  behind  and  a  little  above  the 
natural  situation  with  respect  to  the  ilium;  the 
head  of  the  bone  could  be  felt  neither  in  the 
sitting,  standing,  nor  lying  posture.  Indeed, 
Mr.  B.  Cooper  himself  remarks  that,  "  upon 
taking  into  consideration  all  these  diagnostic 
marks,  I  was  induced  to  consider  the  acci- 
dent a  luxation  on  the  dorsum  of  the  ilium  ; 
although  the  head  of  the  bone  was  not  drawn 
up  so  high  as  usual,  as  indicated  by  the  slight 
shortening  of  the  limb ;  and  the  trochanter 
major  was  also  drawn  further  backwards  than 
is  usual,  in  the  dislocation  on  the  dorsum,  so 
that,  perhaps,  this  might  by  some  surgeons  have 
been  described  as  a  dislocation  to  the  ischiatic 
notch."  Mr.  Cooper  further  adds  : — "  I  doubt, 
however,  if  this  appellation  as  applied  to  a  cer- 
tain variety  of  dislocation  of  the  hip,  does  not 
rather  mystify  than  facilitate  our  diagnosis, 
for  it  leads  to  the  supposition  that  the  head  of 
the  bone  sinks  into  the  osseous  hiatus, — a  cir- 
cumstance which  could  not  occur  even  in  the 
skeleton  itself,  from  the  size  of  the  head  of  the 
bone,  and  much  less  could  it  happen  in  the 
living  subject,  when  this  notch  is  filled  up 
with  ligaments,  muscles,  vessels,  and  nerves." 
This  respectable  surgeon  proposes,  therefore, 
to  expunge  from  the  classification  of  dislocations 
the  luxation  into  the  notch,  but  to  consider  it 
only  as  a  variety  of  the  dislocation  on  the 
dorsum  ilii,  distinguishing  the  one  as  a  luxation 
upwards,  the  other  backwards,  on  the  dorsum. 
To  this  proposition  we  cannot  by  any  means 
assent,  for  we  consider  that  a  dislocation  back- 
wards behind  the  ischium,  and  to  the  ischiatic 
notch  which  is  below  the  level  of  the  ilium, 
never  can  be  properly  designated  a  variety  of 
the  dislocation  on  the  dorsum  ilii,  although  we 
might  assent  to  the  proposition  to  consider  it  a 
variety  of  the  dislocation  backwards.  The 
case  as  described  by  Sir  A.  Cooper,  of  disloca- 
tion on  the  sciatic  notch,  we  are  satisfied  is  to 
be  seen  occasionally, though  rarely,  in  the  living; 
and  the  dissection  made  by  Sir  Astley  himself, 
in  which  he  found  the  head  of  the  bone  resting 
behind  the  acetabulum  on  the  pyriform  muscle, 
the  preparation  of  which  is  to  be  found  in  the 
museum  of  St.  Thomas's  Hospital,  should, 
we  imagine,  place  the  matter  beyond  dispute. 

Anatomical  characters. — We  have,  says  Sir 
Astley  Cooper,  a  good  specimen  in  the  collec- 
tion of  St.  Thomas's  Hospital,  which  I  met 
accidentally  in  a  subject  brought  for  dissection. 
The  original  acetabulum  is  entirely  filled  with  a 
ligamentous  substance,  so  that  the  head  of  the 
bone  could  not  have  been  returned  into  it.  The 
capsular  ligament  is  torn  from  its  connection 
with  the  acetabulum  at  its  anterior  and  posterior 
junction,  but  not  at  its  superior  and  inferior. 
The  ligamentum  teres  is  broken,  and  an  inch  of 

*  Guy's  Hosp.  Repor J,  n.  1836. 


it  still  adheres  to  the  head  of  the  bone.  The 
head  ot  the  bone  rests  behind  the  acetabulum, 
on  the  pyriformis  muscle,  at  the  edge  of  the 
notch  above  the  sacro-sciatic  ligaments.  The 
muscle  on  which  it  rests  is  diminished,  but 
there  has  been  no  attempt  made  to  form  a  new 
bony  socket  for  the  head  of  the  os  femoris. 
Fig.  324. 

Around  the  head  of  the  thigh-bone  a  new 
capsular  ligament  is  formed  ;  it  does  not  adhere 
to  the  articular  cartilage  of  the  ball  of  the 
bone  which  it  surrounds,  but  could,  when 
opened,  be  turned  back  to  the  neck  of  the 
thigh-bone,  so  as  to  leave  its  head  completely 
exposed. 


Fig.  324. 


Luxation  in  the  sciatic  notch. 


Within  the  new  capsular  ligament,  which  is 
formed  of  the  surrounding  cellular  membrane, 
the  broken  ligamentum  teres  is  found.  The 
trochanter  major  is  rather  behind  the  acetabu- 
lum, but  inclined  towards  it  relatively  to  the 
head  of  the  bone.  This  dislocation,  he  adds, 
must  have  existed,  from  the  appearances  of  the 
parts,  many  years.  The  adhesions  were  too 
strong  to  have  admitted  of  any  reduction,  and 
if  reduced,  the  bone  could  not  have  remained 
in  its  original  socket. 

c.  Luxation  upwards  and  inwards  on  the 
pubcs. — This  luxation  is  more  easy  of  detection 
than  any  other  of  the  thigh.  It  happens  from  a 
person  while  walking  putting  his  foot  into 
some  unexpected  hollow  in  the  ground,  and 
his  body  at  the  moment  being  bent  backwards, 
the  head  of  the  bone  is  thrown  forward  upon 
the  os  pubis. 

The  limb  in  this  species  of  dislocation  is 
an  inch  shorter  than  the  unaffected  one ;  the 
knee  and  the  foot  are  turned  outward,  and 

*  From  Sir  A.  Cooper,  pi.  iv.  on  Fractures  and 
Dislocations. 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


821 


cannot  be  rotated  inwards,  nor  flexed  with- 
out causing  acute  suffering.  The  inguinal 
region  is  the  seat  of  the  principal  pains,  which 
however  from  this  point  extend  along  the  thigh, 
and  are  the  consequence  of  the  stretching  which 
the  anterior  crural  nerve  necessarily  suffers  as 
it  is  raised  up  at  the  neck  of  the  bone. 

The  striking  criterion  of  this  dislocation  is, 
that  the  head  of  the  thigh-bone  may  be  dis- 
tinctly felt  upon  the  pubes,  above  the  level  of 
Pou part's  ligament,  and  it  feels  as  a  hard  ball, 
which  is  readily  perceived  to  move  by  bending 
the  thigh-bone.  The  femoral  artery  has  been 
usually  felt  pulsating  along  the  inner  side  of 
the  head  of  the  bone,  but  Mr.  Smith  presented 
lately  to  the  Pathological  Society  the  cast  of 
a  ease  of  this  luxation,  in  which  he  had  noticed 
that  the  femoral  artery  ran  in  a  tortuous 
manner  directly  across  the  head  of  the  dislo- 
cated bone. 

The  great  trochanter  is  drawn  upwards  and 
forwards,  so  as  to  be  situated  in  the  trajet  of  a 
line  which  would  pass  from  the  anterior  infe- 
rior spine  of  the  ilium,  downwards  and  for- 
wards. In  a  case  of  a  dislocation  of  this  spe- 
cies which  was  left  a  long  time  unreduced,  the 
motion  of  the  knee  backwards  and  forwards 
was  fully  twelve  inches.  The  following  case 
was  admitted  into  Jervis  Street  Hospital,  under 
the  care  of  Mr.  O'Keilly,  during  the  time  I 
was  one  of  the  surgeons  to  that  institution,  and 
as  it  seemed  to  me  the  best  marked  case  of  the 
kind  I  had  ever  witnessed,  I  beg  here  to  lay  it 
before  the  reader  from  my  case-book. 

Case. — P.  Bryan,  a  powerful  man,  aged  37, 
was  admitted  into  Jervis  Street  Infirmary, 
Uec.  4,  1828.  He  was  intoxicated  when  the 
accident  which  produced  the  luxation  occurred, 
and  consequently  was  unable  to  give  any  idea 
as  to  how  the  injury  was  produced. 

As  the  patient  lay  on  his  back  in  bed  the 
affected  limb  appeared  to  lie  parallel  to  its 
fellow,  but  then  there  was  an  eversion  of  the 
whole  limb,  and  the  foot  of  course  turned  out- 
wards. One  circumstance  particularly  caught 
our  observation,  viz.  the  preternatural ly  arched 
appearance  which  the  upper  third  of  the  shaft 
of  the  femur  presented  ;  the  adductor  muscles 
were  full  and  prominent;  there  was  an  unusual 
prominence  underneath  Poupart's  ligament; 
the  anterior  superior  spinous  process  appeared 
retired. 

On  making  more  minute  examination  it  was 
found  that  the  eversion  of  the  foot  was  perma- 
nent, and  we  were  surprised  to  find  that  there 
was  but  little  difference  between  the  length  of 
both  limbs  ;  certainly  the  injured  one  was  little 
more  than  half-an-inch  shorter  than  the  sound 
one.  A  considerable  depression  existed  where 
formerly  the  trochanter  major  lay  ;  this  process 
of  bone  was  very  evident,  and  could  be  readily 
felt  about  two  inches  below  and  somewhat 
anterior  to  the  anterior  superior  spinous  pro- 
cess of  the  ilium,  and  about  the  same  distance 
internal  to  it  a  well-marked  prominence  in  the 
inguinal  region  shewed  the  new  situation  which 
the  head  of  the  femur  occupied  ;  along  its 
inner  side  were  seen  and  felt  the  pulsations  of 


the  femoral  artery.  On  communicating  a 
motion  of  rotation  outwards,  the  head  of  the 
bone  could  be  easily  felt  under  the  soft  parts  ; 
the  nates  was  flattened ;  the  femur  was  but 
little  moveable  with  respect  to  the  pelvis,  and 
any  attempt  to  draw  the  thigh  backwards 
caused  great  pain  to  the  patient :  to  flex  it  was 
impossible.  A  motion  of  rotation  outwards 
could  be  communicated  to  the  dislocated  femur, 
but  no  rotation  inwards  was  permitted.  Ad- 
duction of  the  limb  was  admissible,  even  to 
permit  the  knees  to  touch.  When  the  patient 
stood  up,  he  naturally  threw  his  weight  on  the 
sound  limb,  and  the  affected  one  was  flexed 
slightly  at  the  knee,  and  the  heel  touched  the 
inside  of  the  opposite  foot,  as  in  the  "  first 
position"  of  dancers.  The  reduction  of  the 
dislocation  was  effected  in  the  ordinary  method  ; 
indeed  the  rules  laid  down  by  Sir.  A.  Cooper 
were  fully  adopted,  and  in  due  time  succeeded. 

Anatomical  characters  of  this  luxation.— 
Sir  A.  Cooper  gives  us  an  account  of  the  dis- 
section he  made  of  one  of  these  luxations  of  the 
femur  on  the  pubes,  which  had  been  a  long 
time  unreduced;  he  found  the  original  ace- 
tabulum partially  filled  by  bone,  and  in  part 
occupied  by  the  trochanter  major,  and  both  are 
much  altered  in  form  ;  the  capsular  ligament  is 
extensively  lacerated,  and  the  ligamentum  teres 
broken.  The  head  of  the  thigh-bone  had  torn 
up  Poupart's  ligament,  so  as  to  be  admitted 
between  it  and  the  pubes  (jig.  325).   The  head 

Fig.  325. 


Luxation  on  the  pubes.* 

and  neck  of  the  bone  were  thrown  into  a  position 
under  the  iliacus  interims  and  psoas  muscles, 
the  tendons  of  which,  in  passing  to  their  in- 
sertion over  the  neck  of  the  bone,  were  elevated 
by  it  and  put  on  the  stretch.  The  crural  nerve 
passed  on  the  fore-part  of  the  neck  of  the  bone, 

*  From  Sir  A.  Cooper,  loc.  cit.  plate  v. 


822 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


upon  the  iliacus  internus  and  psoas  muscles. 
The  head  and  neck  of  the  thigh-bone  are 
flattened,  and  much  changed  in  their  form. 
Upon  the  pubes  a  new  acetabulum  is  formed 
for  the  neck  of  the  thigh-bone,  for  the  head  of 
the  bone  is  above  the  level  of  the  pubes.  The 
new  acetabulum  extended  upon  each  side  of 
the  neck  of  the  bone,  so  as  to  lock  it  in  a  cer- 
tain direction  upon  the  pubes.  Poupart's 
ligament  confines  it  on  the  fore-part ;  on  the 
inner  side  of  the  neck  of  the  bone  passed  the 
artery  and  vein,  so  that  the  head  of  the  bone 
was  seated  between  the  crural  sheath,  and  the 
anterior  and  inferior  spinous  process  of  the 
ilium. 

d.  Luxation  downwards  and  inwards  into  the 
foramen  ovale. — When  the  femur  is  in  a  forced 
state  of  abduction,  if  violence  be  in  any  man- 
ner applied  so  as  still  further  to  exaggerate  this 
movement,  the  head  of  the  femur  having  pre- 
viously glided  from  above  downwards  in  the 
acetabulum  to  its  utmost,  applies  itself  to  the 
interior  of  the  capsular  ligament,  which  it 
stretches;  if  the  force  be  continued  the  capsule 
soon  gives  way,  and  the  head  of  the  femur, 
bursting  through  the  rent,  is  dislocated  and 
lodged  in  front  of  the  obturator  foramen. 

The  symptoms  by  which  we  recognize  this 
accident  are  very  well  marked,  as  the  limb  in 
this  dislocation  is  two  inches  longer  than  the 
other.  The  body  is  bent  forwards  owing  to  the 
psoas  and  iliacus  internus  muscles  being  put 
upon  the  stretch  (fig.  326).  The  knee  is  consi- 
derably advanced ;  if  the  body  be  erect  it  is  widely 
separated  from  the  other,  and  cannot  be  brought 
without  great  difficulty  towards  the  middle  line 
or  made  to  touch  the  other  knee,  owing  to  the 
extension  of  the  glutaei  and  pyriform  muscles. 
The  foot,  though  widely  separated  from  the 
other,  is  generally  neither  turned  outwards  nor 
inwards,  although  it  varies  a  little  in  this  respect 
in  different  instances,  but  the  position  of  the 
foot  does  not  in  this  case  mark  the  accident. 
The  adductor  muscles  are  elongated  and  form 
a  round  prominent  line  which  extends  from  the 
pubes  to  the  middle  of  the  thigh.  The  foot 
and  the  knee  are  turned  outwards  because  the 
adductor  and  the  other  muscles  which  execute 
the  movement  of  rotation  outwards  are  on  the 
stretch  and  elongated.  The  thigh  cannot  be 
adducted,  and  when  we  wish  to  communicate 
this  movement  to  the  limb  the  patient  feels 
severe  pains  because  of  the  tension  which  the 
glutaei  and  rotators  outwards  suffer.  The  reason 
of  the  flexion  of  the  leg  is  two-fold ;  first  to 
relax  the  hamstring  muscles  which  are  put 
upon  the  stretch  by  the  dislocation,  and  to 
establish  an  approach  to  an  equality  in  the 
length  of  the  limb. 

When  we  examine  closely  the  injured  hip, 
we  notice  a  considerable  hollow  at  the  upper 
and  outer  part  of  the  thigh  where  the  great 
trochanter  is  normally  seen  projecting,  and  a 
depression  is  noticed  below  the  centre  of  Pou- 
part's ligament.  The  head  of  the  dislocated 
bone  can  be  felt  occasionally  at  the  inner  and 
outer  parts  of  the  thigh  towards  the  perineum. 
The  position  of  the  head  of  the  bone  is  below 


Fig.  326. 


Luxation  into  the  foramen  ovale. 

the  acetabulum  and  a  little  anterior  to  it.  The 
bent  position  of  the  body,  the  separated  knees, 
and  the  increased  length  of  the  limb  constitute 
the  striking  and  characteristic  features  of  this 
rare  accident. 

That  excellent  practical  surgeon,  Mr.  Hey 
of  Leeds,  had  not  during  a  period  of  public 
and  private  practice  for  thirty-eight  years  seen 
a  case  of  this  accident  of  luxation  downwards 
and  inwards  into  the  foramen  ovale,  until  in 
the  year  1797  three  patients  were  brought  into 
the  infirmary  of  Leeds.  In  one  of  the  best 
marked  examples  of  this  accident  the  dislocated 
thigh  appeared  much  thicker  at  the  superior 
part  than  the  other;  the  adductor  muscles,  it 
appears,  were  upon  the  stretch,  and  the  inguinal 
hollow  we  can  collect  was  effaced  (perhaps  by 
the  tension  of  the  skin  and  effusion).  Mr.  Hey 
says,  the  head  of  the  bone  could  not  be  dis- 
tinctly felt  through  the  muscles ;  yet,  from  the 
appearance  and  the  touch,  it  was  sufficiently 
evident  that  the  head  of  the  bone  lay  upon  the 
great  foramen  of  the  os  innominatum.  It 
seemed  probable  that  it  had  passed  so  far  from 
the  acetabulum  as  to  be  in  contact  with  the 
descending  part  of  the  os  pubis. 

There  was  in  this  case  a  considerable  hollow 
at  the  upper  and  outer  part  of  the  thigh  where 
the  great  trochanter  is  usually  felt  projecting. 

The  following  case  of  dislocation  of  the 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


823 


femur  into  the  foramen  ovale  I  saw  in  Steevens's 
Hospital,  and  my  friend  Dr.  Osbrey  has  obliged 
me  with  his  notes  of  the  case,  which  were  as 
follows : — 

Michael  Murphy,  at.  21,  a  labourer,  ad- 
mitted June  4th,  1834,  under  Mr.  Colles  with 
dislocation  of  the  head  of  the  femur  into  the 
foramen  ovale. 

He  stands  with  his  entire  weight  upon  the 
sound  side,  the  left  thigh  flexed  on  the  pelvis, 
his  knee  bent,  and  toes  turned  out  and  resting 
on  the  ground,  from  which  the  heel  is  raised  ; 
the  thigh  is  abducted  so  that  he  cannot  bring 
his  knees  nearer  than  within  five  inches  of 
each  other,  when  standing  up  not  within  nine, 
and  at  this  time  his  toes  are  thirteen  inches 
asunder;  the  thigh  is  wasted,  and  he  cannot 
support  any  weight  on  the  limb.  When  asked 
to  walk  without  support  he  places  his  hand 
firmly  on  the  knee,  and  bears  his  weight  on 
the  arm  and  leg  without  throwing  any  of  it  on 
the  thigh.  His  pelvis  is  lower  on  the  injured 
side,  and  there  is  a  slight  curvature  of  the 
spine,  the  convexity  to  the  same  side,  in  conse- 
quence of  which  there  is  great  apparent  length- 
ening of  the  limb.  The  real  difference  when 
measured  from  the  symphysis  pubis  to  the  point 
of  the  inner  ankle  is  two  inches  and  a  half,  but 
there  is  little  or  no  difference  when  measured 
from  the  spine  of  the  ilium  ;  and  when  the 
measurement  is  taken  from  the  tuber  ischii  the 
dislocated  limb  is  two  inches  longer  than  its 
fellow.  There  is  considerable  deformity  about 
the  joint;  a  deep  hollow  exists  immediately 
below  the  anterior  spine  of  the  ilium,  through 
which  the  sartorius  runs  obliquely,  joining  a 
prominent  ridge  when  the  muscle  is  in  action. 
The  prominence  of  the  trochanter  is  altogether 
lost,  and  that  process  can  be  with  difficulty 
felt.  The  fold  of  the  buttock  is  completely 
obliterated,  and  there  is  a  fullness  towards  the 
upper  and  back  part  of  the  thigh,  caused  by 
the  head  of  the  bone,  which  can  be  felt  through 
the  adductor  muscles,  and  seems  to  be  situated 
further  inwards  than  is  usually  described  in 
this  accident.  He  states  that  he  received  the 
injury  five  weeks  ago;  he  was  thrown  down  on 
his  right  side  obliquely  against  a  wall,  by  a 
horse  running  away  with  a  cart,  and  the  wheel 
of  the  cart  passed  over  his  left  hip  above  the 
trochanter ;  lie  felt  great  pain  at  the  time  which 
was  chiefly  referred  to  the  inside  of  the  knee. 
He  was  carried  home  and  nothing  was  done 
for  him  for  a  fortnight,  when  he  went  to  a 
hospital,  where  several  attempts  were  made  at 
reduction ;  all,  however,  failed,  and  after  re- 
maining there  a  fortnight  longer  he  came  up  to 
Dublin  in  the  state  above  described. 

On  the  12th  of  June  two  attempts  to  reduce 
the  bone  failed  altogether,  and  the  man  returned 
to  the  country. 

Anatomical  characters. — It  seems  probable 
that  the  head  of  the  dislocated  femur  passes  so 
much  forwards  and  inwards  from  the  acetabu- 
lum as  to  be  in  contact  with  the  inner  margin 
of  the  thyroid  foramen,  where  this  foramen  is 
completed  by  the  rami  of  the  ischium  and 
Dubes.    The  convexity  of  the  great  trochanter 


has  the  acetabulum  behind  it,  and  the  lesser 
trochanter  is  placed  immediately  external  and 
anterior  to  the  tuberosity  of  the  ischium.  The 
ligamentum  teres  and  lower  part  of  the  capsular 
ligament  have  been  torn  through,  and  the  head 
of  the  bone  "  become  situated  in  the  interior 
and  inner  part  of  the  thigh  upon  the  obturator 
externus  muscle." 

We  have,  says  Sir  Astley  Cooper,  an  ex- 
cellent specimen  of  this  accident  in  the  collec- 
tion of  St.  Thomas's  Hospital,  which  I  dissected 
many  years  ago.  The  head  of  the  thigh-bone 
was  found  resting  on  the  foramen  ovale,  but 
the  obturator  externus  muscle  was  completely 
absorbed,  as  well  as  the  ligament  naturally 
occupying  the  foramen  now  entirely  filled  by 
bone.  Around  the  foramen  ovale  bony  matter 
was  deposited  so  as  to  form  a  deep  cup,  in 
which  the  head  of  the  thigh-bone  was  inclosed, 
but  in  such  a  manner  as  to  allow  considerable 
motion ;  and  the  cup  thus  formed  surrounded 
the  neck  of  the  thigh-bone  without  touching  it, 
and  so  enclosed  its  head  that  it  could  not  be 
removed  from  its  new  socket  without  breaking 
its  edges.  The  inner  side  of  this  new  cup  was 
extremely  smooth,  not  having  the  least  ossified 
projection  at  any  part  to  impede  the  motion  of 
the  head  of  the  bone,  which  was  only  restrained 
by  the  muscles  from  extensive  movements. 

The  original  acetabulum  was  half  filled  by- 
bone,  so  that  it  could  not  have  received  the 
ball  of  the  thigh-bone  if  it  had  been  put  back  into 
its  natural  situation  (fig.  327).  The  head  of  the 
thigh-bone  was  very  little  altered,  its  articular 


Fig.  327. 


Luxation  into  the  foramen  ovale. 


*  From  Sir  A.  Cooper,  pi.  ii. 


824 


ABNORMAL  CONDITIONS  OF  THE  HIP-JOINT. 


cartilage  still  remained,  the  ligamentum  teres 
was  entirely  broken,  and  the  capsular  ligament 
partially  torn  through.  The  pectinalis  muscle 
and  adductor  brevis  had  been  lacerated,  but 
were  united  by  tendon.  The  psoas  muscle  and 
iliacus  interims,  the  glutafi  and  pyriformis,  were 
all  upon  the  stretch. 

e.  Cases  of  unusual  dislocations. —  In  Guy's 
Hospital  Reports  we  find  the  account  of  two 
cases  of  dislocation  of  the  head  of  the  femur 
upwards  and  outwards  towards  the  anterior 
superior  spinous  process  of  the  ilium. 

In  the  first  of  these  cases,  detailed  by  Mr. 
Morgan,  the  affected  leg  (the  left)  was  short- 
ened to  the  extent  of  at  least  two  inches,  the 
foot  was  excessively  everted,  so  much  so  as 
almost  to  give  the  toes  a  direction  backwards. 
The  injured  limb  had  a  tendency  to  cross  that 
of  the  opposite  side,  so  that  the  heel  was  thrown 
over  the  instep  of  the  opposite  foot ;  neverthe- 
less when  the  feet  were  placed  side  by  side, 
they  remained  in  that  position.  The  limb  was 
susceptible  of  all  the  natural  motions  to  some 
extent,  with  the  exception  of  rotation,  but  the 
man  complained  of  great  pain  when  under  ex- 
amination. The  projection  of  the  trochanter 
major  was  entirely  lost,  whilst  the  luxated  head 
of  the  bone  might  be  felt  under  Poupart's  liga- 
ment, just  below  and  to  the  inner  side  of  the 
anterior  superior  spinous  process  of  the  ilium, 
and  it  apparently  lay  between  the  anterior  and 
inferior  spinous  process  of  the  ilium,  and  the 
junction  of  this  last  bone  with  the  pubes;  it 
thus  rested  upon  the  brim  of  the  pelvis,  and 
projected  upwards  towards  the  abdomen ;  the 
femoral  artery  was  not  displaced  in  this  dislo- 
cation, but  could  be  traced  taking  its  usual 
course,  and  consequently  situated  to  the  inner 
side  of  the  displaced  bone. 

In  this  case  a  speedy  reduction  of  the  dislo- 
cated bone  was  effected,  but  in  the  second  case 
I  have  alluded  to,  the  bone  was  left  unreduced 
for  years.  We  are  indebted  for  the  publication 
of  the  whole  case,  accompanied  with  the  dis- 
section, to  Mr.  Bransby  Cooper,  who  tells  us 
that  the  preparation  which  illustrates  the  acci- 
dent the  patient  suffered  from,  was  presented  to 
Sir  Astley  Cooper,  by  his  friend  Mr.  Old- 
know  of  Nottingham,  and  the  bones  are  pre- 
served in  the  museum  of  Guy's  Hospital.  The 
subject  of  the  accident  was  a  lunatic,  aged  28, 
and  as  far  as  we  can  learn  from  the  detail  of 
the  case  given,  his  symptoms  were  very  much 
those  which  Mr.  Morgan's  patient  presented 
before  the  dislocation  was  reduced.* 

Upon  dissection  it  was  found  that  the  old 
acetabulum  was  deprived  of  articular  cartilage, 
and  was  in  part  filled  up  by  bony  deposit,  so 
as  to  be  rendered  wholly  unfit  for  the  reception 
of  the  head  of  the  femur.  The  new  acetabulum 
was  nearly  directly  above  the  original  cavity, 
and  was  bounded  on  the  outside  by  the  two 
anterior  spinous  processes,  and  on  the  inside  by 
the  line  of  junction  of  the  ilium  and  the  hori- 
zontal branch  of  the  pubes,  that  is  to  say,  by 
the  ileo-pubal  eminence.    The  form  of  the  new 

*  Guy's  Hospital  Reports,  January,  1836,  p.  99. 


cavity  for  the  reception  of  the  head  of  the  femur 
was  very  like  the  natural  acetabulum,  but  not 
quite  of  equal  dimensions  ;  it  is  protected  above 
by  a  growth  of  bone  which  overlapped  the  head 
of  the  femur,  and  must  have  formed  the  princi- 
pal point  of  support  of  that  bone.  The  inferior 
part  of  the  new  acetabulum  was  the  most  defi- 
cient. The  trochanter  major  sunk  partly  into 
the  old  acetabulum,  and  polished  points  on  both 
the  old  and  new  acetabulum  indicated  where 
the  head  of  the  femur  and  trochanter  major 
played  in  the  various  motions  this  imperfect 
joint  enjoyed. 

We  are  not  informed  how  the  muscles  were 
altered  from  their  normal  state,  but  may  infer 
that  most  of  them  were  more  or  less  atrophied  ; 
it  is  probable,  however,  that  both  the  obturator 
externus  and  internus  were  put  much  upon  the 
stretch,  and  retained  the  bone  more  or  less 
downwards.  It  would  have  been  interesting  to 
have  learned  the  precise  situation  of  the  rectus 
femoris,  tensor  vaginae,  and  sartorius,  psoas, 
and  iliacus,  but  we  can  easily  imagine  that 
the  latter  were  much  shortened,  and  that  they 
were  raised  up  from  the  pubes  by  the  dislocated 
bone,  the  tendon  of  the  rectus  must  have  been 
thrown  outwards  over  the  rest  of  the  femur  and 
trochanter  major.  The  head  of  the  femur  was 
altered  from  its  original  figure,  so  as  to  be 
adapted  to  the  new  acetabulum,  portions  of  it 
being  diminished  where  it  did  not  come  in  con- 
tact with  the  new  cavity,  so  that  its  spheroidal 
figure  was  lost.  The  periosteum  of  the  femur, 
as  well  as  of  the  new  acetabulum,  assisted  in 
forming  the  new  capsular  ligament.  The  arti- 
cular cartilage  of  the  head  of  the  femur  has 
been  absorbed,  and  the  same  porcelain-like 
concretion,  as  is  seen  in  the  acetabulum,  is 
provided  at  corresponding  points.  From  the 
form  of  the  articulating  surfaces,  and  the  fixed 
position  of  the  femur,  both  at  the  head  and  the 
trochanter  major,  it  will  be  observed  that  no 
other  motion  than  flexion  could  be  permitted, 
and  even  that  motion,  from  the  closeness  of  the 
attachment  at  the  trochanter,  but  to  a  limited 
extent. 

Luxation  of  the  head  of  the  femur  down- 
wards and  backwards.  —  This  luxation  may 
be  considered  as  a  very  rare  accident.  When 
the  last  edition  of  Sir  A.  Cooper's  work  on 
Fractures  and  Luxations  was  published,  the 
baronet  had  not  seen  such  an  accident,  as  he 
remarked,  "  it  is  to  be  remembered  that  there 
is  no  such  accident  as  a  dislocation  of  the  hip 
downwards  and  backwards." 

Dupuytren  says,  "  I  have  only  twice  or  thrice 
seen  this  luxation  downwards  and  backwards. 
The  limb  was  then  twisted  inwards,  a  little 
elongated,  and  it  was  impossible  to  adjust  it  to 
its  ordinary  place  and  position,  without  reducing 
the  luxation,  which  once  accomplished,  the  dis- 
placement did  not  a  second  time  recur." 

My  friend  Mr.  Wormald,  assistant-surgeon 
to  St.  Bartholomew's  Hospital,  has  published  an 
account  of  an  accident  of  this  kind  in  the  Medical 
Gazette,  June  28,  1837,  and  the  preparation, 
which  shews  the  relative  position  of  the  head 
of  the  dislocated  bone,  &c.  and  the  acetabulum, 


HYPEREMIA  AND  ANEMIA. 


825 


is  preserved  in  the  museum  of  the  hospital. 
Fig.  328. 

Fig.  328. 


Dislocation  downwards  and  backwards. 
B,  obturator  internus ;    C,  trochanter  major;  D, 
the  acetabulum;    E,  obturator  externus ;   V,  sciatic 
nerve;    I,  shaft  of  the  femur. 

"  A  maniac  who  eluded  the  vigilance  of  his 
keepers,  leaped  from  a  third  story  window. 
Besides  dislocating  his  thigh,  he  received  other 
injuries,  of  which  he  died  in  about  an  hour. 

"  On  examining  the  dislocated  limb,  it  was 
found  considerably  shortened  and  inverted, 
forming  about  half  a  right  angle  with  the  body, 
the  shaft  of  the  femur  crossing  the  symphysis 
pubis  was  fixed  immoveably  in  this  situation ; 
as  the  patient  was  sinking,  no  attempt  was 
made  at  reduction. 

"  Twelve  hours  after  the  death  of  the  patient 
I  commenced  the  dissection,  by  reflecting  the 
gluteus  maximus,  when  I  found  some  of  the 
fibres  of  the  glutoeus  medius  and  minimus  rup- 
tured at  their  posterior  edge.  The  pyriformis 
and  gemelli  were  also  partially  torn,  but  those 
portions  of  the  tendon  of  the  obturator  internus 
which  pass  through  the  lesser  ischiatic  notch 
were  drawn  out,  and  separated  from  their  con- 
nexion with  the  muscular  fibres  ;  the  head  of 
the  femur  presented  itself  through  a  rent  of  the 
capsule,  opposite  to  the  upper  part  of  the  tuber 
ischii  above  the  quadratus,  so  that  the  great 
sciatic  nerve  was  somewhat  displaced  and 
pressed  against  the  tuber  ischii. 

"  In  this  case  there  was  no  difficulty  in  de- 
tecting the  nature  of  the  injury,  as,  besides  the 
symptoms  already  described,  the  head  of  the 
femur  could  be  felt  resting  on  the  tuber  ischii, 
covered  by  the  outer  edge  of  the  gluteus  maxi- 
mus. 

"  If  this  patient  had  been  in  a  condition  to 
attempt  reduction  of  the  dislocation  by  fixing 
the  pelvis,  and  employing  extension  in  the 
direction  of  the  shaft  of  the  bone,  at  the  same 
time  everting  the  limb,  the  head  of  the  femur 
would  have  been  brought  opposite  the  rent  in 
the  capsule,  and  would  have  been  in  all  pro- 


bability replaced  in  the  acetabulum  without 
greater  difficulty  than  is  usually  experienced." 

(  Robert  Adams.) 

HYPEREMIA  and  ANiEMlA,  (v^, 
super ;  a,,  negative ;  and  onyLoc,  sanguis)  (in 
morbid  anatomy).  These  are  terms  employed 
to  denote  opposite  conditions  of  the  various 
membranous  or  parenchymatous  textures  of  the 
body  as  regards  the  quantity  of  blood  contained 
in  their  bloodvessels ;  the  former,  as  its  deriva- 
tion denotes,  indicating  a  superabundant  sup- 
ply of  blood,  the  latter  a  deficiency  of  that 
fluid.  They  are  useful  terms  to  the  anatomist, 
inasmuch  as  they  express  simply  the  state  of  a 
texture,  without  any  theory  being  involved 
respecting  the  cause  or  origin  of  that  state. 
It  ought  always  to  be  the  first  business  of  the 
anatomist  to  observe  carefully  the  actual  con- 
dition of  the  parts  submitted  to  his  examination; 
this  having  been  done,  he  should  search  dili- 
gently for  some  cause,  mechanical,  chemical,  or 
vital,  which  will  satisfactorily  account  for  the 
phenomena. 

All  vascular  textures,  it  is  obvious,  are  liable 
to  these  conditions;  and  it  is  equally  evident 
that  the  relative  frequency  of  their  occurrence 
in  different  textures  will  coincide  with  the 
natural  facility  of  the  flow  of  blood  to  or  from 
them,  as  well  as  the  quantity  of  blood  con- 
tained in  them  in  the  normal  state.  Thus  the 
lung  or  the  spleen  is  favourable  for  the  forma- 
tion of  hyperemia,  as  well  from  the  large 
supply  of  blood  in  each  as  from  the  free  com- 
munication between  their  respective  arterial  and 
venous  systems,  and  between  the  ramifications 
of  vessels  of  the  same  kind. 

A  bleached  slate  of  the  same  organs  may  be 
taken  as  a  good  example  of  the  opposite  con- 
dition, or  anaemia;  but  the  most  complete 
anosmia  is,  of  course,  to  be  found  in  organs  or 
tissues  which,  in  the  natural  state,  contain  but 
a  small  quantity  of  blood. 

It  is  important  to  notice  that  hyperemia  may 
occur  independently  of  disease  and  altogether 
as  a  cadaveric  phenomenon,  and  there  is  no 
mistake  more  frequently  committed  by  the 
incautious  observer  than  that  of  attributing  to 
the  influence  of  a  morbid  process  during  life 
appearances  which  simply  result  from  the 
ordinary  physical  laws  which  death  has  allowed 
to  exert  full  sway  over  the  tissues.  Indeed,  it 
is  only  since  anatomists  have  ceased  to  regard 
every  instance  of  an  unduly  injected  tissue  as 
a  diseased  one,  that  valuable  practical  conclu- 
sions have  been  drawn  from  post-mortem  obser- 
vations. 

We  may  pronounce  hyperemia  not  to  be  mor- 
bid, when  it  is  found  to  occupy  only  the  most 
dependent  parts  of  organs,  the  blood  having 
deserted  the  vessels  of  the  more  elevated  parts. 
At  every  post-mcrtem  examination  we  have 
abundant  examples  of  hyperemia  of  this  kind  ; 
if  the  body  have  been  laid  on  the  back,  as  is 
usually  the  case,  the  whole  of  the  skin  of  that 
region  is  largely  injected  with  blood  ;  the  sub- 
cutaneous cellular  tissue  is  in  a  similar  condi- 
tion, and  the  adjacent  muscles  more  or  less  so 


826 


HYPERTROPHY  AND  ATROPHY. 


likewise.  The  blood  in  these  cases  is  chiefly 
contained  in  capillaries  and  veins,  the  ramifica- 
tions of  which  will  be  found  fully  injected. 
The  dependent  parts  of  all  the  vascular  tissues 
and  organs  of  a  body  thus  placed,  exhibit 
similar  appearances.  The  scalp  on  the  occiput, 
the  posterior  lobes  of  the  brain,  and  the 
cerebellum  are  much  more  injected  than  the 
anterior  parts  of  the  same  textures.  The  pos- 
terior parts  of  the  lungs,  of  the  stomach  and 
intestines,  of  the  spleen,  liver,  and  kidneys 
exhibit  the  same  state  of  vascular  congestion. 
That  this  results  altogether  from  position  and 
the  blood  in  the  vessels  obeying  the  universal 
law  of  gravitation,  may  be  clearly  proved  by 
reversing  the  position  of  the  body,  when  after 
a  little  time  the  blood  will  desert  the  former 
dependent  but  now  elevated  parts,  and  those 
portions  of  the  texture  which  before  were  almost 
devoid  of  blood  from  their  elevated  position, 
now  have  their  vessels  filled  with  it. 

When  hyperemia  results  from  a  mechanical 
obstacle  to  the  circulation,  it  is  not  accumulated 
at  one  part  of  an  organ  or  viscus,  but  all  parts 
appear  equally  gorged  with  the  blood.  In 
certain  diseased  states  of  the  heart  and  liver, 
the  intestinal  canal  presents  an  example  of  this 
general  hyperemia,  owing  to  the  mechanical 
obstacle  to  the  free  circulation  of  the  blood  in 
the  right  heart.  The  circumference  of  the 
intestine  is  every  where  reddened  by  the  blood 
accumulated  in  its  capillaries. 

Andral,  by  whom  of  late  years  the  term  hy- 
peremia itself  was  brought  into  use  in  morbid 
anatomy,  gives  the  following  varieties  of  it. 
1.  Active  or  sthenic  hyperemia,  denoting  the 
state  indicated  by  the  ordinary  expression 
acute  inflammation.  2.  Passive  or  asthenic, 
resulting  from  diminished  tone  in  the  capil- 
lary vessels.  3.  Mechanical,  from  an  obstacle 
to  the  venous  circulation.  4.  Cadaveric  or 
post-mortem,  being  the  result  of  those  physical 
and  chemical  laws  to  which  all  inorganic 
matter  is  subject,  and  to  which  all  organized 
bodies  are  also  subjected  when  the  vital  spark 
has  ceased  to  animate  them.*  This  last  variety, 
moreover,  he  subdivides  into  two  genera. 
First  gemts,  hyperemia  produced  at  the  mo- 
ment of  death. — Cause;  the  contractility  of 
tissue  which  resides  in  the  small  arteries,  con- 
tinuing to  act  after  the  heart  has  ceased  to  beat. 
Second  genus,  hyperemia  produced  at  a  certain 
period  after  death.  This  genus  comprehends 
the  following  species  :■ — 1.  Hyperemia  by  hy- 
postasis or  dependent  position.  2.  Hyperemia 
by  transudation  of  the  blood  or  of  some  of  its 
component  parts  through  the  parietes  of  its 
vessels.    3.  Hyperemia  by  chemical  affinities. 

Anaemia,  a  term  long  in  use  to  express  a 
general  exsangueous  and  cachectic  condition 
of  the  body,  is  also  applied  to  a  local  state 
of  exsangueousness.  Any  cause  which  would 
impede  or  cut  off  the  wonted  supply  of  blood 
to  a  part  will  occasion  this  condition  in  it;  the 
diminution  in  the  calibre  of  the  principal  artery 
of  an  organ,  from  mechanical  pressure  or  disease 

*  Path.  Anat.  by  Townsend,  vol.  i.  p.  15. 


in  the  vessel,  or  a  depressed  state  of  the  nervous 
influence.  Hyperemia  of  one  organ  may  give 
rise  to  anaemia  of  another,  the  former  as  it 
were  attracting  the  blood  away  from  the 
latter. 

The  general  condition  of  anosmia  is  not  un- 
frequently  brought  under  the  physician's  notice 
either  as  the  result  of  some  excessive  and  long- 
continued  hemorrhage  or  of  some  deranged 
state  of  general  nutrition,  giving  rise  to  a  deterio- 
ration in  the  quality  of  the  blood,  or  a  general 
deficiency  in  the  powers  of  the  nervous  in- 
fluence. The  surface  of  the  body  is  pale,  the 
mucous  membranes,  as  far  as  they  can  be  seen, 
partake  of  the  same  exsangueous  state,  the 
secretions  are  defective  and  vitiated,  the  tone 
of  the  muscular  and  vascular  systems  is  con- 
siderably diminished,  and  this  state  may  go  on 
without  any  specific  morbid  change  in  any 
organ,  beyond  its  participation  in  the  general 
scanty  supply  of  the  blood,  or  it  may  co-exist 
with  an  organic  disease,  which,  although  it 
may  have  been  at  first  the  result  of  the  primary 
exciting  cause  of  the  anaemia,  now  serves  to 
increase  it,  or  offers  the  greatest  impediment  to 
its  removal. 

(R.  B.  Todd.) 

HYPERTROPHYandATROPHY,  (vve?, 
super,  a,,priv.,  and  T^(pu,nutrio),{m  morbid  ana- 
tomy). When  any  organ  or  tissue  has  acquired 
a  certain  increase  of  developement,  without 
any  manifest  alteration  of  its  natural  structure, 
it  is  said  to  be  in  the  state  of  hypertrophy — 
the  increase  being  due  to  a  greater  activity 
of  the  nutritive  process  in  the  part  affected. 
A  familiar  example  of  hypertrophy,  although 
not  morbid,  is  afforded  by  the  augmentation 
which  muscular  fibre  acquires  in  consequence 
of  increased  action.  If  the  biceps  muscle  of 
one  arm  be  actively  exercised,  while  that  of  the 
other  does  not  undergo  any  considerable  degree 
of  action,  the  former  acquires  a  great  increase 
of  size,  it  becomes  denser  and  firmer,  and 
manifests  the  physical  and  vital  phenomena  of 
the  muscular  tissue  with  more  than  ordinary 
energy. 

There  is  no  texture  in  the  body  which  does 
not  occasionally  exhibit  evidence  of  the  hyper- 
trophous  condition.  The  circumstances  which 
favour  its  production  are  an  abundant  and  a 
free  afflux  of  blood  to  the  part,  an  energetic 
nervous  influence  and  an  increased  demand 
upon  the  organ,  or  increased  exercise  if  it  be 
muscular;  and  indeed  these  are  the  almost  in- 
variable conditions  under  which  hypertrophy  is 
manifested.  The  heart  becomes  hypertrophous 
under  an  exalted  nervous  influence,  or  from  a 
necessarily  increased  exercise  from  the  effort  to 
overcome  some  obstacle  to  the  free  circulation  of 
the  blood  through  its  cavities ;  one  kidney 
acquires  a  great  increase  of  size  if  the  other 
one  be  incapable  of  performing  its  function. 
It  may  be  said  that  the  liver  is  in  a  state  of 
hypertrophy  in  the  foetus  in  utero,  for  it  has 
a  larger  supply  of  blood  than  in  extra-uterine 
life,  and  the  lungs  have  not  as  yet  begun  to 
share  with  it  in  the  office  of  decarbonizing  the 


ILIAC  ARTERIES. 


827 


venous  blood.  The  bladder  also,  like  the 
heart,  acquires  an  enormous  developement  of 
its  muscular  coat,  when  any  obstacle  obstructs 
the  free  flow  of  the  urine  from  it.  The  physi- 
cal condition,  then,  of  a  hypertrophous  organ 
differs  but  in  degree  from  that  of  the  part  in 
its  normal  state.  There  are,  in  general,  in- 
crease of^size,  of  weight,  and  of  consistence, 
with  more  or  less  alteration  of  shape  consequent 
upon  the  former ;  an  increased  supply  of  blood, 
and  a  consequent  heightening  of  colour.  To 
judge  therefore  how  far  an  organ  has  experi- 
enced hypertrophy,  the  anatomist  must  care- 
fully compare  its  present  condition,  as  regards 
size,  weight,  colour,  consistence,  and  supply 
of  blood,  with  the  average  state  of  the  parts  in 
health. 

Atrophy  is  not  only  opposite  in  its  nature  to 
hypertrophy,  but  it  results  from  causes  of  an 
entirely  opposite  kind.  A  defective  state  in 
the  nutritive  process  is  its  immediate  cause  : — 
the  affected  part  shows  manifest  signs  of  wast- 
ing ;  it  diminishes  in  size  and  in  consistence ; 
it  loses  its  colour  from  the  deficient  supply  of 
blood  ;  its  physical  and  vital  properties  are 
manifestly  altered,  and  are  fully  developed. 
When  the  wasting  has  gone  to  its  greatest  ex- 
tent, the  natural  texture  disappears,  or  is  so 
altered  as  to  present  but  few  of  the  characters 
of  its  normal  condition.  As  frequent  exercise 
and  use  favour  the  production  of  hypertrophy, 
so  on  the  other  hand  disuse  and  inactivity 
give  rise  to  atrophy.  Neither  the  vascular  nor 
the  nervous  systems  of  such  parts  afford  their 
wonted  supplies  ;  and  those  physical  characters 
which  are  present  in  hypertrophy  in  an  exalted 
condition,  are  in  atrophy  either  absent  altoge- 
ther, or  but  feebly  developed.  The  muscles 
of  paralytic  limbs,  the  hearts  of  old  persons 
which  have  been  overloaded  with  fat,  the 
diminution  in  size  and  almost  total  disappear- 
ance of  the  thymus  gland  in  the  adult,  the 
diminution  of  the  left  lobe  of  the  liver  in  extra- 
uterine life,  the  obliteration  and  conversion  into 
a  fibrous  cord  of  certain  disused  venous  and 
arterial  canals,  and  the  wasting  of  the  optic 
nerve  where  the  eye  is  destroyed,  are  examples 
of  atrophy  of  every  day's  occurrence.  (See  the 
articles  on  the  morbid  anatomy  of  the  different 
textures  and  organs.) 

(R.  B.  Todd.) 

ILIAC  ARTERIES*  (so  called  from  their 
situation  in  the  iliac  regions)  are  three  upon  each 
side  of  the  body,  viz.  the  primitive  iliac,  the 
internal  and  the  external  iliacs ;  they  are  the 
main  arteries  of  the  pelvis  and  the  lower  ex- 
tremity. 

Primitive  iliac  arteries  (common  iliacs, 

*  But  little  dissection  is  necessary  to  display  the 
iliac  arteries  ;  the  abdominal  wall  having  been  di- 
vided and  thrown  bads,  the  peritoneum  may  be 
detached  from  without  inward,  along  with  the  con- 
tained viscus,  from  the  iliac  fossa,  which  having 
been  done  to  a  sufficient  extent,  care  being  at  the 
same  time  taken  to  leave  uninjured  the  spermatic 
vessels  the  vas  deferens  and  the  ureter,  the  iliac 
arteries  will  be  exposed  still  covered  by  their  imme- 
diate investment. 


urterice  iliac  a  primitive,  s.  communes,  s.  pelvi- 
crurules;  Fr.  Artiresiliuques primitives;  Germ. 
Gemeinschaftliche  Huft-pntsadern,)  are  two, 
one  on  each  side :  they  are  vessels  of  great 
size,  from  three-eighths  to  four-eighths  of 
an  inch  in  diameter,  but  short,  their  length 
varying  from  one  and  a  half  to  two  and  a  half 
or  three-quarters  of  an  inch,  the  arteries  being 
longer  or  shorter,  according  to  the  height 
at  which  the  aorta  divides.  They  arise  from 
the  termination  of  the  aorta,  their  origin 
corresponding,  as  a  mean  point,  to  the  in- 
terval between  the  bodies  of  the  fourth  and 
fifth  lumbar  vertebras,  and  somewhat  to  the 
left  of  the  middle  line  of  the  vertebral 
column ;  the  exact  height  of  their  origin, 
however,  varies  considerably,  ranging  in  ordi- 
nary between  the  bodies  of  the  third  and 
fifth  vertebrae  ;  but  they  have  been  found  to 
arise  very  near  to  the  diaphragm.*"  From  their 
origin  they  descend,  and  at  the  same  time  in- 
cline outward  and  backward,  forming  with  each 
other  an  acute  angle,  but  more  so  in  the  male 
than  in  the  female  subject,  because  of  the 
greater  width  of  the  pelvis  in  the  latter,  until 
they  reach  a  point  ranging  between  the  body  of 
the  fifth  lumbar  vertebra  and  the  sacro-iliac 
articulation, f  where  they  terminate  by  dividing 
into  the  internal  and  external  iliacs.  The  point 
of  reference  usually  assigned  for  this  division  is 
the  sacro-iliac  articulation  ;  but  this  appears  not 
to  be  strictly  correct,  the  exact  point  varying  as 
well  on  the  opposite  sides  of  the  same  as  in 
different  subjects;  for  the  most  part  the  division 
takes  place  between  the  two  points,  which  have 
been  mentioned  ;  at  times  nearer  to  one,  at 
times  to  the  other,  and  according  to  Velpeau, 
it  usually  occurs  nearer  to  the  spine  upon  the 
right  than  upon  the  left  side ;  hence,  according 
to  the  same  authority,  the  right  external  iliac 
artery  is  longer  than  the  left,  and  were  it  pos- 
sible to  ascertain  these  diversities  of  origin 
during  life,  advantage  would  result  therefrom, 
inasmuch  as  the  prospect  of  success  in  high 
ligature  of  the  external  iliac  must  be  influenced 
by  the  height  of  its  origin,  and  the  difficulty  of 
reaching  the  primitive  or  the  internal  iliacs  must 
be  increased  in  the  same  proportion.  These 
views  appear  well-founded  ;  the  division  of  the 
primitive  iliac  rarely  takes  place  so  far  outward 
as  the  sacro-iliac  articulation,  and  for  the  most 
part  it  is  nearer  to  the  body  of  the  vertebra,  or 
higher  upon  the  right  than  the  left  side,  and 
therefore  the  external  iliac  of  that  side  is  usually 
the  longer,  but  this  disposition  is  not  constant; 
the  division  of  the  ri^ht  primitive  artery  is  not 
always  higher  than  that  of  the  left,  nor  conse- 
quently the  right  external  longer,  and  therefore 
while  probability  is  in  favour  of  the  conclusion 
which  the  facts  stated  indicate,  it  cannot  be 
absolutely  relied  upon. 

The  primitive  iliac  arteries  are  of  the  same 
size,  and  nearly  the  same  length ;  the  right, 
however,  is  considered  for  the  most  part  some- 
what the  longer,  because  of  the  situation  of  the 

*  Velpeau,  who  cites  Petsche  on  the  authority  of 
J.  F.  Meckel, 
t  Bogros. 


828 


ILIAC  ARTERIES. 


aorta  upon  the  left  side  of  the  spine;  Velpeau, 
however,  seems  to  question  the  existence  of  any 
difference  in  the  length  of  the  two  vessels,  inas- 
much as  the  right  divides  generally  nearer  to  the 
spine  than  the  left,  the  inclination  of  their  origin 
to  the  left  being  thus  compensated,  but  to  what- 
ever extent  this  view  may  hold  good,  it  is  by  no 
means  strictly  correct ;  in  fact  the  length  of  the 
arteries,  whether  comparative  or  absolute,  is  far 
from  regular;  nor  is  the  preponderance,  when 
present,  always  upon  the  same  side ;  the  opinion 
generally  entertained  is  probably  correct,  the 
light  artery  being  in  the  majority  of  instances 
somewhat  longer  than  the  left ;  but  the  writer 
has  found  the  left  the  longer  of  the  two,  and 
the  same  disposition  has  been  observed  by  J.  F. 
Meckel;  this  is, however,  an  unusual  disposition. 

The  relations  of  the  arteries  are  simple. 
During  their  descent  they  are  situate  in  front  of 
the  bodies  of  the  lumbar  vertebras,  with  the 
intervening  fibro-cartilages,  of  one,  two,  or  more 
of  these  bones,  according  to  the  height  at  which 
the  arteries  arise,  and  also  of  the  lateral  part  of 
the  base  of  the  sacrum  ;  they  are  both  covered 
upon  three  sides  by  the  peritoneum,  viz.  in 
front  and  laterally,  the  membrane  descending 
upon  them  from  the  root  of  the  mesentery;  the 
mesentery  itself  also  and  the  small  intestines 
are  placed  before  them,  and  the  latter  overlap 
them  upon  either  side.  Farther,  they  are  in 
front  of  the  superior  branches  of  the  middle 
sacral  artery  and  of  the  sympathetic  nerve. 
That  of  the  right  side  at  its  outset  is  placed 
before  the  left  primitive  iliac  vein,  which  it 
crosses  at  its  junction  with  the  cava,'and  par- 
tially before  the  commencement  of  the  cava 
itself ;  during  its  course  it  is  in  front  of  the 
right  primitive  vein,  at  first  only  partially,  but, 
as  it  proceeds,  covering  it  to  a  greater  extent, 
until  at  its  termination  it  is  directly  before  it. 

External  to  both,  but  on  a  plane  posterior  to 
them,  are  the  psoae  muscles,  the  left  artery  how- 
ever being  nearer  to  the  muscle  than  the  right, 
between  which  and  the  psoas  the  right  primitive 
vein  and  the  cava  intervene,  being  at  the  same 
time  posterior  to  it. 

Internal  to  both  at  their  origin  is  the  middle 
sacral  artery ;  on  the  left  side  the  left  primitive 
vein  lies  along  the  inside  of  the  artery,  but  on  a 
plane  behind  it. 

Anteriorly  the  arteries  are  crossed  at  their 
termination  by  the  corresponding  ureter,  that 
duct  being  interposed  between  the  peritoneum 
and  the  vessel,  but  more  adherent  to  the  former. 
The  relation  of  the  ureter  to  the  iliac  arteries  is 
not  uniform,  either  on  opposite  sides  or  in 
different  subjects ;  the  bifurcation  of  the  pri- 
mitive iliac  may  be  assumed  as  the  mean  point 
of  reference  for  its  transit,  the  duct  descending 
into  the  pelvis  between  the  external  and  internal 
iliacs,  and  before  the  internal ;  but  its  precise 
relation  will  depend  upon  the  height  at  which 
the  bifurcation  takes  place  and  the  side  of  the 
body  to  which  it  belongs,  and  hence  it  very 
frequently,  if  not  usually,  crosses  the  external 
iliac  upon  the  right  and  the  termination  of  the 
internal  on  the  left. 

The  artery  and  vein,  the  relations  of  which 
differ  remarkably  upon  the  two  sides,  the  vein 


beirfg  external  upon  the  right  and  internal  upon 
the  left,  and  upon  both  posterior,  are  enclosed 
within  a  condensed  cellular  investment,  pro- 
longed upward  upon  the  aorta  and  downward 
upon  the  secondary  iliacs ;  upon  the  primitive 
vessels  it  is  so  thin  that  it  may  at  times  seem 
absent;  but,  as  it  descends,  it  increases  in 
thickness,  and  acquires  upon  the  external  iliacs 
considerable  strength. 

The  primitive  iliac  arteries  ordinarily  give 
only  minute  branches  to  the  adjoining  parts, 
viz.  the  ureter,  the  peritoneum,  the.  vein,  lym- 
phatic glands  and  cellular  structure ;  but  occa- 
sionally they  have  been  found  to  give  off  the 
ilio-lumbar  artery,  and  more  rarely  a  renal  or 
spermatic  artery.* 

Although, according  to  the  view  usually  taken, 
the  primitive  iliac  terminates  by  dividing  into 
internal  and  external,  yet  in  many  instances  it 
will  be  found  that  the  primitive  and  external 
iliacs  appear  as  one  vessel  giving  off  the  internal 
from  its  posterior  side,  and  nearly  at  right 
angles,  while  in  the  foetus  the  reverse  seems  the 
case,  the  primitive  and  internal  being  continuous 
and  rather  giving  off  the  external. 

Internal  iliac  artery. f  ( Arteria  iliuca 
interna,  s.  hypogastrica,  s.  umbilicalis  ;  Fr. 
artere  iliaque  interne,  ou  hypogastrique ;  Germ. 
Becken-pulsader  oder  innere  Huft-pulsader.) 
This  artery  from  the  time  of  birth  supplies  the 
viscera  and  parietes  of  the  pelvis,  both  externally 
and  internally  ;  prior  to  that  epoch  it  is  the 
channel  through  which  the  blood  is  trans- 
mitted from  the  body  of  the  foetus  to  the 
placenta,  whence  it  may  then  be  termed  with 
propriety  the  "  placental  artery,"  since  such  is 
its  chief  office,  the  other  distribution  being  of 
inconsiderable  extent,  and  the  divisions  of  the 
artery  intended  for  it  small  in  proportion ; 
hence  the  vessel  presents  a  remarkable  contrast 
at  the  two  periods  of  life,  in  the  foetus  being  a 
large  and  long  vessel  extending  from  the  ter- 
mination of  the  aorta,  for,  as  has  been  before 
stated,  it  seems  at  that  time  the  continuation  of 
the  primitive  iliac  artery,  to  the  placenta  giving 
off  in  its  course  small  branches  to  the  viscera 
and  parietes  of  the  pelvis,  while  in  after  life  the 
placental  artery  has  disappeared,  and  in  its 
stead  is  found  a  short  trunk  of  considerable 
size, — the  commencement  of  the  placental 
artery  as  it  had  been — from  which  arise  nume- 
rous vessels  for  the  pelvis  and  its  viscera. 

The  internal  iliac  arises  from  the  posterior 
side  of  the  primitive  iliac  artery,}  between  the 
body  of  the  last  lumbar  vertebra  or  the  sacro- 
vertebral  angle,  and  the  sacro-iliac  articulation, 
but  generally  higher  upon  the  right  side  than 
the  left ;  it  descends  into  the  pelvis  in  front  of 

*  J.  F.  Meckel. 

t  The  internal  iliac  and  its  branches  should  be 
examined  first  with  the  pelvis  complete,  the  peri- 
toneum and  viscera  being  detached  trom  its  lateral 
wall,  and  the  latter  alternately  empty  and  distended  ; 
afterward  a  section  of  the  pelvis  may  be  made 
through  the  symphysis  pubis  and  the  middle  of  the 
sacrum,  preserving  the  viscera  with  their  attach- 
ments to  one  side  ;  but  this  should  not  be  done 
until  after  the  dissection  of  the  perineum. 

|  See  primitive  iliac  for  point  and  mo^e  of 
division. 


ILIAC  ARTERIES. 


829 


the  sacro-iliac  articulation  or  of  the  lateral  part 
of  the  sacrum,  as  it  may  be,  inclining  backward 
and  outward,  and  describing  a  curve  concave 
forward,  until  it  reaches  the  superior  part  of  the 
great  sciatic  notch,  where  it  usually  divides  ; 
this  however  is  by  no  means  uniform,  the  point 
of  its  division  ranging  between  the  brim  of  the 
pelvis  and  the  notch.  The  internal  iliac  is  an 
artery  of  great  size,  but  in  the  adult  smaller 
than  the  external ;  its  course  is  somewhat  tor- 
tuous and  short,  from  one  and  a  half  to  two  and 
a  half  inches. 

During  its  descent  the  artery  is  placed  before 
the  lumbo-sacral  nerve,  on  the  left  side  before 
the  primitive  iliac  vein,  and  on  both  before  the 
sacro-iliac  articulation  or  the  lateral  part  of  the 
sacrum.  Before  it  are  in  the  male  the  bladder 
or  its  lateral  connections,  in  the  female  the 
uterus  and  its  broad  fold  of  peritoneum  ;  ex- 
ternally the  artery  corresponds  to  the  internal 
iliac  and  the  commencement  of  the  primitive 
iliac  veins,  to  the  inside  of  the  psoas  magnus 
muscle,  to  the  brim  of  the  pelvis,  to  the  obtu- 
rator nerve,  which  it  crosses  nearly  at  right 
angles,  to  the  lumbo-sacral  and  first  of  the 
anterior  branches  of  the  sacral  nerves,  and  to 
the  superior  attachment  of  the  pyriformis 
muscle  :  the  ilio-lumbar  artery  is  also  external 
to  the  internal  iliac,  between  it  and  the  wall  of 
the  pelvis.  Internal  to  it  are  the  peritoneum, 
the  rectum  with  its  mesentery,  and  the  superior 
hemorrhoidal  vessels,  (these  parts  being  nearer 
to  the  artery  upon  the  left  than  the  right,)  and 
the  small  intestine  when  in  the  pelvis. 

The  external  iliac  vessels  are  above,  before, 
and  external  to  the  internal.*  In  the  foetus  the 
condition  of  the  internal  iliac  differs  remarkably 
from  that  which  it  presents  in  after  life;  in  it 
both  in  size  and  direction  this  artery  appears  the 
continuation  of  the  primitive  trunk,  exceeding 
the  external  as  much  as  afterward  it  is  exceeded 
by  it.  It  is  the  channel  which  conveys  the  blood 
to  the  placenta,  and  it  is  generally  entitled  the 
"  hypogastric  or  umbilical  artery  ;"  "  placental'' 
would  certainly  be  preferable.  It  passes  from 
the  primitive  iliac  or  rather  from  the  aorta,  for 
there  the  primitive  iliac  appears  only  the  com- 
mencement of  the  placental  artery,  downward 
and  at  first  outward  as  far  as  the  sacro-iliac 
articulation,  where  it  gives  off  the  external 
iliac  artery,  then  forward  to  the  side  of  the 
bladder,  descending  but  little  into  the  pelvis 
and  at  the  same  time  giving  off  pelvic  branches; 
it  next  changes  its  direction  and  ascends  in- 
clining inward  toward  the  umbilicus,  at  first  by 
the  side  of  the  bladder  and  then  in  the  anterior 
abdominal  wall,  between  the  peritoneum  and 
the  rectus  muscle  or  its  sheath,  and  on  either 
side  of  the  urachus ;  thus  forming  a  curve 
convex  downward  through  the  concavity  of 
which  pass  the  vas  deferens  or  round  ligament 
before,  the  ureter  posteriorly  and  the  rectum, 
the  extremity  of  the  ilium  and  the  appendages 
of  the  uterus  in  the  mean  space.  Having  reached 
the  umbilicus  the  artery  escapes  through  it 
from  the  body  of  the  foetus  and  is  conducted 

*  'Hiis  is  to  be  understood  to  refer  to  the  recum- 
bent posture ;  in  the  erect  posture  the  external  arc 
not  superior  to  the  internal  vessels. 


by  the  umbilical  cord  to  the  placenta  ;  during 
their  transit  to  the  placenta  the  arteries  at  the 
very  early  periods  of  utero-gestation,  are  straight, 
but  afterwards,  in  proportion  as  the  develope- 
ment  advances,  they  become  tortuous,  and  are 
twined  round  the  umbilical  placental  vein, 
whence  the  length  of  the  arteries  exceeds  that 
of  the  cord  which  varies  from  one  to  two  feet. 
At  the  placenta  the  two  arteries  are  connected 
by  a  considerable  anastomosis,  and  divide  into 
numerous  branches,  which  subdivide  minutely 
in  the  lobes  of  that  structure,  the  ramifications 
of  the  several  lobes  being  distinct  from  each 
other;  ordinarily  the  two  vessels  are  distinct 
until  they  approach  the  placenta,  but  they  have 
been  found  to  unite  into  a  single  one  before 
escaping  from  the  abdomen  of  the  foetus.* 
The  placental  arteries  give  off  within  the  body 
of  the  foetus  branches  similar  in  number  and 
destination  with  those  of  the  primitive  iliac  of 
the  adult,  but  in  a  rudimental  condition; 
between  the  summit  of  the  bladder  and  the 
umbilicus  however  they  do  not  furnish  branches, 
and  hence,  the  circulation  through  them  be- 
tween these  points  ceasing  at  birth,  they  be- 
come obliterated  to  the  same  extent  and 
connected  into  impervious  cords,  known  by  the 
name  of  umbilical  ligaments ;  these  hold  the 
same  course  and  relation  with  the  original 
vessels,  and  are  less  distinct  in  proportion  to 
the  age  of  the  subject;  they  are  covered  upon 
their  abdominal  aspect  by  the  peritoneum, 
which  is  reflected  upon  them  to  a  greater  or 
less  extent  according  to  the  subject,  and  thereby 
forms  triangular  falciform  folds,  the  base  of 
which  is  below  in  the  iliac  fossa,  and  the  apex 
above  toward  the  umbilicus,  and  in  the  free 
edge  of  which  the  ligament  is  contained.  At 
a  point  intermediate  to  the  brim  of  the  pelvis 
and  the  upper  part  of  the  sacro-sciatic  notch  the 
internal  iliac  artery  divides  into  branches  ;  these 
are  numerous,  amounting  altogether  in  the  male 
to  nine,  and  in  the  female  to  eleven  ;  but  in 
their  mode  of  origin  they  vary  very  much, 
arising  sometimes  separately,  sometimes  by 
common  trunks,  but  for  the  most  part  from 
two,  into  which  the  iliac  divides  ;  these  are  an 
anterior  one  giving  off  the  hemorrhoidal,  the 
umbilical,  the  vesical,  the  uterine,  the  vaginal, 
the  sciatic  and  internal  pudic,  and  a  posterior, 
from  which  arise  the  ilio-lumbar,  the  lateral 
sacral,  the  obturator  and  the  gluteal.  Another 
diversity  in  the  mode  of  their  origin  is  that  of 
the  obturator  from  the  epigastric  or  external 
iliac. 

The  branches  of  the  internal  iliac  are  arranged 
either  into  four  sets,  viz.  posterior,  anterior, 
internal,  and  inferior,!  or  into  two,  internal  and 
external,];  the  former  distributed  within,  the 
latter  without  the  pelvis  ;  the  latter  seems  the 
more  simple  division,  and  is  the  one  which  will 
be  adopted  in  this  article. 

The  internal  branches  are  in  the  male  five, 
in  the  female  seven  ;  they  are  as  follow — 

1.  The  iliolumbar  artery  varies  in  size  and  ori- 
gin ;  for  the  most  part  it  arises  from  the  posterior 

*  Cloquet. 
t  Cloquet. 
X  Harrison 


830 


ILIAC  ARTERIES. 


division  of  the  internal  iliac,  at  times  from  the 
iliac  itself;  at  times  from  the  gluteal,  occa- 
sionally from  the  primitive  iliac,  and  frequently 
by  a  trunk  common  to  it  and  the  lateral  sacral ; 
from  its  origin,  which  is  somewhat  below  the 
base  of  the  sacrum,  it  runs  upward,  outward, 
and  backward  toward  the  iliac  fossa,  passes  in 
front  of  the  sacro-iliac  articulation  and  the 
lumbo-sacral  nerve  and  external  to  the  obturator 
nerve;  having  surmounted  the  outlet  of  the 
pelvis  it  passes  behind  the  psoas  muscle,  the 
external  iliac  vessels  and  the  anterior  crural 
nerve,  and  emerges  from  behind  them  at  the 
superior  and  internal  part  of  the  fossa,  where  it 
divides.  As  the  artery  emerges  from  the  pelvis 
it  gives  off'  a  branch  which  descends  along  the 
brim,  gives  small  branches  to  the  inside  of  the 
psoas,  and  finally  anastomoses  with  a  branch 
from  the  epigastric  artery  ;  while  concealed  by 
the  psoas  it  gives  branches  to  it  and  the  iliacus 
internus.  Finally  it  divides  into  two  sets  of 
branches,  superior  or  ascending,  and  external  or 
transverse ;  the  former  ascend  beneath  the 
psoas,  supply  it,  the  iliacus  and  the  quadratus 
lumborum,  send  a  branch  into  the  vertebral 
canal  through  one  of  the  inferior  intervertebral 
foramina,  and  finally  communicate  with  the 
inferior  lumbar  arteries.  The  external  set  pass 
outward  into  the  iliac  fossa,  and  are  distin- 
guished into  two,  a  superficial  and  deep ;  the 
former  run  across  the  iliacus  muscle,  superficial 
to  it  and  beneath  the  iliac  fascia,  supply  the 
muscle  and  anastomose  freely  with  corres- 
ponding branches  from  the  circumflex  branch 
of  the  external  iliac  artery  :  the  superior  of  the 
superficial  branches  runs  round  the  crest  of  the 
ilium  within  its  inner  edge,  as  it  proceeds  it 
gives  branches  downward  to  the  iliacus  and 
upward  to  the  quadratus  lumborum,  the  trans- 
versalis  and  oblique  muscles,  some  of  which 
turn  over  the  crest  and  communicate  with 
branches  of  the  gluteal  artery  ;  finally  it  ends  in 
a  direct  and  free  anastomosis  with  the  ultimate 
branch  of  the  circumflex  artery,  the  fossa  having 
thus  an  artificial  circle  formed  around  it  in- 
ternally, between  these  branches  and  the  original 
iliacs.  The  branches  of  the  deep  set  pass  into 
the  substance  of  the  iliacus  muscle,  and  between 
it  and  the  bone,  and  are  distributed  to  the 
muscle,  the  periosteum,  and  the  bone,  one  of 
them  entering  the  ilium  through  the  canal  to  be 
observed  at  the  bottom  of  the  fossa ;  their  deep 
branches  also  communicate  with  the  circumflex 
iliac,  the  gluteal  and  the  external  circumflex 
femoral  arteries.  Sometimes  there  are  two 
ilio-lumbar  arteries. 

2.  The  lateral  sacral  artery  may  be  either 
single  or  double,  and  arises  either  from  the 
posterior  division  of  the  iliac,  from  the  iliac 
itself  on  its  inner  side,  from  the  gluteal,  or  the 
sciatic,  and  frequently  in  common  with  the 
ilio-lumbar  :  it  runs  downward,  and  inward  in 
front  of  the  lateral  part  of  the  sacrum,  the  sacral 
nerves  at  their  exit  from  the  anterior  sacral 
foramina,  and  the  pyriform  muscle  external  to 
the  middle  sacral  artery  and  the  sympathetic 
nerve  ;  it  descends  to  the  extremity  of  the 
sacrum  and  then  anastomoses  with  the  middle 
sacral  and  the  artery  of  the  other  side  ;  at  tunes 


instead  of  terminating  thus  it  enters  the  sacral 
canal  through  the  third  or  fourth  foramen  and 
is  distributed  internally.  Its  branches  are  dis- 
tinguished into  two  sets,  an  anterior  or  internal 
and  a  posterior  or  external.  The  former  are 
distributed  to  the  sacral  nerves  within  the 
pelvis,  to  the  pyriform  muscle,  to  the  pelvic 
cellular  tissue  and  glands,  to  the  levator  ani 
muscle  and  to  the  sacrum.  The  posterior  are 
the  larger,  they  are  usually  four,  but  at  times 
more  numerous,  two  branches  sometimes  taking 
the  same  course ;  they  pass  backward  along 
the  sacral  nerves,  through  the  sacral  foramina, 
into  the  canal,  and  then  divide  into  two,  of 
which  one  is  distributed  within  the  canal  to  the 
nerves  and  their  ganglia,  to  the  membranes  and 
the  sacrum ;  the  other  escapes  backward 
through  the  posterior  sacral  foramen,  and  is 
distributed  upon  the  back  of  the  sacrum  in  the 
sacro-vertebral  channel,  anastomosing  with  the 
adjoining  vessels. 

3.  The  yniddle  hemorrhoidal  artery  is  some- 
times wanting,  its  place  being  supplied  by 
branches  from  the  other  divisions  of  the  iliac; 
it  is  of  about  the  same  size  as  the  previous 
arteries,  and  varies  very  much  in  its  source, 
arising  from  the  anterior  division  of  the  iliac, 
from  that  vessel  itself  or  from  the  pudic,  the 
sciatic  or  lateral  sacral  arteries,  it  runs  down- 
ward, forward,  and  inward  along  the  side  and 
front  of  the  rectum,  at  first  between  the  intes- 
tine and  the  levator  ani,  and  then  between  it 
and  the  fundus  of  the  bladder  in  man  and  the 
vagina  in  the  female,  and  divides  into  branches, 
of  which  the  greater  part  are  distributed  to  the 
rectum,  anastomosing  with  the  branches  of  the 
superior  hemorrhoidal  from  above  and  with 
those  of  the  inferior  hemorrhoidal  from  below  ; 
others  are  distributed  to  the  fundus  of  the 
bladder,  the  prostate  and  vesiculas  in  man,  and 
to  the  vagina  in  the  female. 

4.  The  vesical  arteries  are  subject  to  great 
variety  ;  they  are  numerous  and  smaller  than 
the  last  described  :  they  are  distinguished  by 
Harrison  into  three  sets,  inferior,  middle,  and 
superior  ;  the  inferior  set  consists  of  those 
branches  given  to  the  fundus  of  the  bladder  by 
the  middle  hemorrhoidal,  pudic,  and  sciatic 
arteries ;  the  superior,  furnished  by  the  um- 
bilical, are  two  or  more  in  number,  and  are 
distributed  to  the  superior  region  of  the  bladder, 
but  the  middle  is  a  single  vessel  larger  than 
the  others,  and  given  off  by  the  iliac  artery, 
though  frequently  arising  from  some  of  its 
branches,  particularly  the  umbilical :  it  is  en- 
titled by  Chaussier  "  vesico-prostatique :"  it 
passes  downward  and  inward  to  the  fundus  of 
the  bladder,  and  then  divides  into  branches 
distributed  to  the  bladder,  and  in  the  male  also 
to  the  prostate,  the  vesiculas  and  neck  of  the 
bladder. 

5.  The  umbilical  artery.  In  the  adult  sub- 
ject a  small  arterial  canal  usually  from  an  inch 
and  a  half  to  two  inches  and  a  half  long  ex- 
tends from  the  termination  of  the  internal  iliac, 
or  from  one  of  its  branches  to  the  superior 
lateral  part  of  the  bladder;  there  it  is  continued 
with,  or  seems  to  have  attached  to  it  superiorly 
the  umbilical  ligament,  the  artery  appearing 


ILIAC  ARTERIES. 


rather  to  be  continuous  with  the  last  branch 
arising  from  it.  A  variable  number  of  branches 
arise  from  it ;  these  are  generally  the  superior 
vesical,  at  times  the  vaginal  or  the  uterine  ;  and 
according  to  their  number  and  size  its  size 
varies ;  it  is  not  destined  to  any  part,  but  only 
gives  rise  to  these  branches,  being  in  reality  not 
a  branch  of  the  iliac  but  so  much  of  the  vessel, 
originally  the  umbilical  or  placental,  as  inter- 
venes between  the  origin  of  the  great  branches 
and  the  point  at  which  it  becomes  impervious, 
which  remains  open  because  of  the  origin  of 
the  vesical  arteries,  &c.  from  it,  but  is  thus  re- 
duced in  size  because  of  their  minuteness. 

6.  The  uterine  artery  arises  either  from  the 
anterior  division  of  the  iliac,  or  from  the  pudic, 
or  at  times  from  the  umbilical ;  it  runs  forward, 
inward,  and  somewhat  downward,  until  it 
reaches  the  superior  lateral  part  of  the  vagina, 
and  entering  the  broad  peritoneal  fold  of  the 
uterus  it  ascends  in  it  along  the  lateral  region 
of  the  uterus  in  a  very  tortuous  manner,  its 
tortuosity  increasing  as  it  proceeds.  As  it  as- 
cends, it  gives  off  a  considerable  number  of 
transverse  branches,  which  attach  themselves 
to  both  surfaces  of  the  organ,  penetrate  its 
substance,  and  supply  it  with  blood,  anasto- 
mosing, at  the  same  time,  freely  with  those 
from  the  other  side.  When  it  has  reached  the 
attachment  of  the  ligament  of  the  ovary,  the 
artery  anastomoses  with  the  spermatic  artery. 
Before  the  artery  attaches  itself  to  the  uterus,  it 
gives  a  considerable  branch  to  the  vagina,  which 
descends  along  it  to  a  greater  or  less  extent 
and  is  distributed  to  both  its  aspects.  Branches 
also  go  from  it  to  the  Fallopian  tube,  the  round 
ligament,  and  the  ligament  of  the  ovary,  and 
likewise  communicate  with  branches  of  the 
spermatic. 

The  uterine  artery  in  the  unimpregnated  con- 
dition of  the  uterus  is  a  small  vessel,  little,  if  at 
all,  larger  than  the  hemorrhoidal  or  vesical 
arteries,  but  during  impregnation,  and  the  more 
so  in  proportion  as  that  state  advances,  it  un- 
dergoes a  remarkable  change,  becoming  greatly 
enlarged,  so  much  so  as  to  equal  or  exceed  in 
size  any  of  the  other  branches  of  the  internal 
iliac  ;  and  at  the  same  time  assuming  a  most 
tortuous  arrangement  as  well  in  its  branches  as 
in  its  trunk. 

7.  The  vaginal  artery  arises  also,  when  pre- 
sent, from  the  anterior  division  of  the  iliac,  or 
from  the  pudic,  the  uterine,  the  umbilical,  or 
hemorrhoidal ;  it  is  therefore  very  irregular  and 
often  absent,  its  place  being  supplied  by 
branches  from  others.  It  runs  forward  and 
downward  along  the  side  of  the  vagina,  dis- 
tributing branches  to  it,  and  also  to  the  bladder 
and  rectum.  At  the  extremity  of  the  vagina  it 
terminates  in  the  external  genital  organs,  and 
communicates  with  the  branches  of  the  pudic 
artery. 

The  external  branches  of  the  internal  iliac 
artery  are  four,  viz. 

1 .  The  obturator  or  thyroid  arteri/,  ( artere 
sous-pubio-femorale,  Chauss.)  is  a  vessel  of  con- 
siderable size,  inferior  only  to  the  gluteal,  pu- 
dic, and  sciatic  branches,  and  about  equal  to 
the  epigastric  artery,  but  irregular  in  that  as 


well  as  in  other  respects.  It  arises  most  fre- 
quently from  the  posterior  division  of  the 
internal  iliac  or  from  the  iliac  itself  imme- 
diately before  its  division ;  it  runs  forward  and 
somewhat  downward  along  the  lateral  wall  of 
the  pelvis  toward  the  superior  posterior  part  of 
the  subpubic  or  thyroid  foramen,  through 
which  it  escapes  from  the  pelvis  into  the  supe- 
rior internal  part  of  the  thigh.  The  course  of 
the  vessel  may  be  divided  into  three  parts  : — 
1st,  that  within  the  pelvis  ;  2d,  that  in  the  sub- 
pubic canal ;  3d,  that  in  the  thigh.  Within 
the  pelvis  the  artery  is  nearly  parallel  to  the 
brim  of  the  pelvis,  or  ilio-pectineal  line,  and 
from  one-half  to  three-fourths  of  an  inch  be- 
neath it,  it  holds  a  similar  relation  to  the  exter- 
nal iliac  vessels,  which  are  above  the  line  and 
from  which  it  is  distant  from  three-fourths  of  an 
inch  to  one  and  one-fourth.  It  is  accompanied 
by  the  obturator  vein  and  nerve,  and  is  placed 
between  them,  the  nerve  being  above  and  the 
vein  beneath  it.  It  is  situate  within  the  pelvic 
fascia;  externally  it  rests  against  this  fascia 
above  the  origin  of  the  levator  ani  muscle,  and 
separated  by  it  from  the  internal  obturator 
muscle  ;  internally  it  corresponds  in  front  to 
the  side  of  the  bladder  to  an  extent  proportioned 
to  the  degree  to  which  that  viscus  may  be  dis- 
tended, and  is  connected  to  it  by  cellular  sub- 
stance ;  posteriorly  it  corresponds  to  the  peri- 
toneum of  the  pelvis,  the  ureter,  and  at  times 
to  the  anterior  division  of  the  iliac  artery  or 
some  of  its  other  branches.  In  this  part  of  its 
course  it  gives  off  a  branch  which  ascends-  to 
the  iliacus  and  psoas,  brandies  to  the  obtura- 
tor internus,  to  the  lymphatic  glands  of  the 
pelvis  and  the  bladder;  lastly,  as  it  approaches 
the  subpubic  foramen  it  gives  an  important 
branch,  which  ascends  posterior  to  the  pubis, 
distributes  small  branches  as  it  proceeds,  and 
ends  in  an  anastomosis  with  a  branch,  which 
descends  from  the  epigastric  artery.  Harrison 
has  occasionally  found  a  considerable  branch 
given  off  in  this  situation,  which  passed  to  the 
side  of  the  prostate  and  the  perineum,  supply- 
ing the  place  of  deficient  branches  of  the  pudic 
artery.- 

In  escaping  from  the  pelvis  the  artery  is 
contained  in  an  oblique  canal  leading  inward 
and  forward.  This  canal,  the  subpubic,  is 
bounded  superiorly  and  externally  by  the  pu- 
bis, which  presents  on  the  under  surface  of  its 
horizontal  ramus  an  oblique  channel,  by  which 
the  roof  of  the  canal  is  formed  ;  inferiorly  and 
internally  it  is  bounded  by  the  margins  of  the 
obturator  muscles  and  ligament;  toward  the 
pelvis  it  presents  a  defined  aperture  circum- 
scribed above  by  the  pubis  and  below  by  the 
pelvic  fascia,  the  attachment  of  which  to  the 
bone  is  interrupted  at  the  part  at  which  the 
artery  passes  out,  and  which  describing  a 
curve  beneath  the  vessels,  between  its  points 
of  attachment  at  either  side  contributes  thus  to 
form  a  rounded  aperture  through  which  they 
escape  without  perforating  the  fascia ;  a  thin 
prolongation  of  the  fascia  is  detached  from  it 
beneath  the  vessels  into  the  canal.  Hernia 
occasionally  protrudes  through  this  canal,  and 
the  artery  has  been  found  by  Cooper  behind 


832 


ILIAC  ARTERIES. 


the  neck  of  the  sac  and  rather  to  its  inner  side. 
While  within  the  canal  the  artery  gives  outward 
a  considerable  branch — its  posterior  or  exter- 
nal, or  it  might  be  with  propriety  called  its 
thyroid  branch — which  runs  downward  and 
backward  along  the  external  margin  of  the 
thyroid  foramen,  between  the  two  obturator 
muscles,  giving  them  branches,  and  at  times 
altogether  consumed  in  them.  Having  reached 
the  tuberosity  of  the  ischium,  it  gives  branches 
to  the  quadratus  and  adductor  magnus  muscles, 
to  the  upper  attachments  of  the  flexors  of  the 
leg,  and  to  the  ilio-femoral  articulation,  into 
which  it  sometimes  sends  through  the  cotyloid 
notch  a  branch  more  frequently  supplied  by 
the  internal  circumflex  (femoral)  artery  ;  it  also 
sends  another  round  the  thyroid  foramen, 
which  meets  a  similar  branch  from  the  obtura- 
tor. It  anastomoses  with  the  internal  circum- 
flex and  the  sciatic  arteries.  At  its  entrance 
into  the  thigh,  the  obturator  artery  is  situate 
above  and  before  the  obturator  externus  muscle, 
and  behind  the  pectinalis,  which  with  some  of 
the  fibres  of  the  adductor  longus  must  be  divided 
in  order  to  expose  the  vessel.  It  descends  be- 
tween the  pectinalis,  the  long  and  short  adduc- 
tors, and  is  distributed  to  them,  the  adductor 
magnus,  the  gracilis,  and  the  integuments  upon 
the  upper  and  inner  part  of  the  thigh.  It  gives 
also  a  branch,  which  runs  round  the  margin 
of  the  thyroid  foramen,  and  meets  the  branch 
already  described  from  its  thyroid  branch.  The 
artery  anastomoses  freely  with  the  internal  cir- 
cumflex artery. 

The  obturator  artery  presents  many  varieties 
as  to  its  source,  of  which  some  are  deserving 
of  particular  attention.  According  to  J.  F. 
Meckel  its  ordinary  source  is  the  posterior 
division  of  the  internal  iliac,  either  immediately 
or  by  a  trunk  common  to  it  and  the  ilio-lumbar, 
but  at  least  once  in  ten  times  it  arises  from  another 
source.  The  next  most  frequent  is  the  internal 
iliac  itself  above  and  before  its  division ;  then 
the  anterior  division  of  the  iliac ;  occasionally 
the  external  iliac,  and  sometimes  the  femoral, 
even  so  low  as  two  inches  from  Poupart's  liga- 
ment. The  most  frequent  variety,  and  which 
according  to  the  same  authority  is  as  common 
as  the  origin  from  the  internal  iliac  itself,  is 
that  the  artery  arises  from  the  epigastric,  or  from 
a  trunk  common  to  both.  Sometimes  it  has  a 
double  origin,  being  formed  by  the  union  of 
two  branches  of  equal  size,  one  from  the  epi- 
gastric, and  the  other  from  the  internal  iliac, 
and  at  times  it  has  a  different  source  upon  op- 
posite sides.  In  every  case  the  destination  of 
the  artery  is  the  same ;  it  runs  to  the  inner 
aperture  of  the  subpubic  canal,  in  order  to 
escape  to  the  thigh,  and  in  so  doing  it  holds  a 
very  intimate  relation  to  the  internal  femoral 
ring  in  those  instances  in  which  it  proceeds 
either  from  the  epigastric  or  from  the  femoral. 
When  it  arises  from  the  epigastric,  it  runs 
obliquely  downward,  backward,  and  inward, 
above  the  crural  arch,  toward  the  superior 
aperture  of  the  pelvis,  then  entering  the  pelvis 
posterior  to  the  pubis  it  turns  downward  be- 
neath it,  and  gains  the  subpubic  foramen. 
During  its  descent  into  the  pelvis  the  artery 


superiorly  is  covered  by  the  peritoneum,  and 
inferiorly  corresponds  to  Poupart's  ligament 
and  the  internal  femoral  ring,  but  the  side  of 
the  ring,  at  which  it  may  be  placed,  varies  in 
different  instances.  When  the  common  trunk 
from  which  the  epigastric  and  obturator  arise  is 
short,  the  obturator  lies  close  to  the  inside  of 
the  external  iliac  vein  and  then  is  situate  on 
the  outer  side  of  the  ring,  while  when  the  com- 
mon trunk  is  long  the  artery  is  more  remote 
from  the  vein,  coasts  along  the  base  of  Gimber- 
nat's  ligament,  and  thus  runs  obliquely  across 
the  front  and  inner  side  of  the  aperture.  Ac- 
cording to  the  case,  therefore,  will  be  the  rela- 
tion of  the  artery  to  the  neck  of  femoral  hernia  ; 
in  the  former  it  will  be  situate  external  and 
posterior  to  it,  in  the  latter  anterior  and  inter- 
nal. 

When  hernia  descends  not  only  into  the  lym- 
phatic compartment  of  the  sheath,  but,  as  has 
been  observed  by  Burns,  also  into  that  belong- 
ing to  the  vein,  thus  forming  a  double  protru- 
sion, the  artery  may,  if  the  common  trunk  be 
short,  be  situate  external  to  the  neck  of  the 
former  and  internal  to  that  of  the  latter. 

The  comparative  frequency  of  this  mode  of 
origin  of  the  obturator  artery  has  been  diffe- 
rently estimated.  According  to  Monro  it  oc- 
curs in  one  of  twenty  cases  ;  Velpeau  coincides 
in  this  opinion;  Lawrence  states  it  to  be  once  in 
ten  ;  J.  F.  Meckel  considers  it  to  be  as  frequent 
as  that  from  the  internal  iliac ;  and  according 
to  the  observations  of  Cloquet  the  proportion 
of  instances  in  250  subjects  in  which  the  artery 
was  found  to  arise  from  the  epigastric,  whether 
on  one  or  both  sides,  was  one  in  three,  and  that 
of  all  the  origins  from  the  epigastric  to  all 
those  from  other  sources  was  still  greater,  about 
I..24.  A  more  important  question  is  the  pro- 
portion borne  by  those  instances  in  which  the 
obturator  arising  from  the  epigastric  is  situate 
on  the  inside  of  the  neck  of  the  hernia,  to  the 
total  number  of  such  cases,  or  to  that  of  cases 
of  femoral  hernia  requiring  operation,  for  it  is 
obviously  with  it  that  the  operator  is  concerned. 
Cooper  has  not  met  the  artery  on  the  inside  of 
the  hernia,  though  in  six  of  twenty-one  cases 
he  found  the  origin  from  the  epigastric ;  and 
Lawrence  states  that  the  proportion  of  the  for- 
mer cases  does  not  exceed  one  in  eight  or  ten, 
and  therefore  that  the  obturator  artery  would 
be  endangered  only  once  in  eighty  or  one  hun- 
dred operations. 

When  the  obturator  arises  from  the  femoral 
artery,  which  Cloquet  found  in  six  of  250 
subjects,  it  ascends  into  the  abdomen  beneath 
the  crural  arch,  along  the  pectinalis  muscle  and 
internal  to  the  femoral  vein,  and  in  femoral 
hernia  is  found  behind  the  sac. 

We  are  indebted  to  J.  F.  Meckel  for  solving 
the  apparent  irregularity  of  these  origins  of  the» 
obturator,  and  reducing  them  to  a  mere  varia- 
tion of  the  normal  condition  ;  the  obturator,  as 
has  been  stated,  is  normally  connected  with  the 
epigastric  by  an  anastomotic  branch,  and  hence 
may  be  considered  as  having  two  origins,  an 
anterior  and  a  posterior,  a  disposition  the  reality 
of  which  is  more  manifest  at  the  earlier  periods 
of  life,  and  according  as  the  one  or  the  other 


ILIAC  ARTERIES. 


833 


may  be  deficient  or  more  developed,  the  obtu- 
rator will  be  derived  principally  or  altogether 
from  the  internal  iliac  or  from  the  epigastric  ; 
when  both  are  equally  so  it  will  present  the 
double  origin. 

2.  The  gluteal  artery,  denominated  also 
posterior  iliac,  is  the  largest  branch  of  the 
internal  iliac,  and  arises  from,  or  is  the  conti- 
nuation of  the  posterior  division  of  that  vessel ; 
it  runs  downward,  backward,  and  outward,  until 
it  reaches  the  superior  part  of  the  great  sciatic 
notch ;  it  then  changes  the  direction  of  its 
course,  and  making  a  turn  passes  directly  out- 
Ward  between  the  lumbo-sacral  and  the  anterior 
branch  of  the  first  sacral  nerves,  and  escapes 
from  the  pelvis  through  the  upper  part  of  the 
notch  above  the  pyriformis  muscle,  and  accom- 
panied by  the  superior  gluteal  nerve.  As  soon 
as  the  artery  has  escaped  from  within  the  pelvis 
and  gained  its  external  aspect,  it  divides  into 
branches.  The  trunk  of  this  artery,  as  it  is  the 
largest,  so  is  it  the  shortest  of  the  branches  of 
the  iliac;  within  the  pelvis  it  corresponds  ex* 
ternally  to  the  lumbo-sacral  nerve,  internally  to 
the  rectum,  and  inferiorly  to  the  first  sacral 
nerve  and  the  pyriformis ;  it  gives  small 
branches  to  the  rectum,  the  pyriformis,  and  the 
surrounding  cellular  structure  ;  at  times  it  also 
gives  off  the  llio-lumbar,  the  lateral  sacral,  or 
the  obturator. 

At  its  exit  posteriorly  from  the  pelvis  it  is 
situate  between  the  adjoining  margins  of  the 
pyriformis  and  the  gluteus  minimus,  and  it  is 
covered  by  the  gluteus  maximus. 

The  branches  into  which  it  divides  after  its 
escape  are  two,  a  superficial  and  deep  one. 
The  first  passes  outward  and  upward  between 
the  glutei  maximus  and  medius,  and  divides 
into  numerous  branches,  which  are  distributed 
to  these  muscles,  particularly  to  the  maximus; 
many  of  them  descend  in  its  substance  toward 
its  insertion,  and  there  meet  branches  of  the 
circumflex  (femoral)  and  sciatic  arteries;  others 
pass  through  the  muscle,  become  superficial, 
and  supply  the  integument  and  subcutaneous 
fat;  others  again  pass  onward,  traverse  the 
attachment  of  the  gluteus  maximus  to  the  sa- 
crum, and  are  distributed  to  the  muscles  and 
integuments  of  the  posterior  sacral  region. 

The  second,  the  deep  branch,  passes  outward, 
upward,  and  forward,  between  the  glutei  medius 
and  minimus  muscles  toward  the  superior 
anterior  spinous  process  of  the  ilium  in  an 
arched  course  around  the  attachment  of  the 
gluteus  minimus.  As  it  proceeds  it  gives  off 
numerous  branches  upward  from  its  convexity 
and  downward  from  its  concavity ;  the  former 
are  distributed  to  the  gluteus  medius;  the  lat- 
ter are  chiefly  two,  of  which  one  runs  forward 
and  downward  toward  the  anterior  part  of  the 
great  trochanter  between  the  two  muscles,  gives 
branches  to  both,  and  finally  throws  itself  into 
the  gluteus  medius  near  the  trochanter,  and  is 
consumed  in  it :  it  communicates  freely  with 
the  external  circumflex  artery.  The  other  runs 
downward  and  forward  toward  the  back  of  the 
trochanter,  lies  for  some  way  upon  the  gluteus 
minimus,  or  over  the  interval  between  it  and 
the  pyriformis,  gives  branches  to  both  muscles, 

VOL.  IF. 


and  then  gains  the  surface  of  the  oS  innomina- 
tum  by  traversing  the  gluteus  or  by  passing 
between  it  and  the  pyriformis,  pursues  its  course 
upon  the  bone,  to  which  it  gives  an  artery,  above 
the  llio-femoral  articulation,  to  the  capsule  of 
which  it  also  gives  branches,  and  approaching 
the  anterior  inferior  spinous  process  of  the  ilium 
it  terminates  in  supplying  the  gluteus  minimus, 
and  anastomosing  with  the  external  circumflex 
artery. 

The  deep  division  of  the  gluteal  artery  hav- 
ing run  round  the  line  of  attachment  of  the 
gluteus  minimus,  and  reached  the  superior 
anterior  spinous  process,  terminates  in  an  anas- 
tomosis with  the  circumflex  iliac,  the  ilio-lumbar, 
and  the  external  circumflex  arteries;  branches 
also  turn  over  the  crest  of  the  ilium,  and  so 
communicate  with  the  iliolumbar.  The  deep 
division,  also,  furnishes  a  nutritious  artery  to 
the  ilium,  the  canal  for  which  is  to  be  seen  on 
the  dorsum  of  the  bone.  The  branches  of  the 
gluteal  artery  are  numerous  and  large  ;  in  order 
to  expose  them  the  gluteus  maximus  having 
been  dissected  clean  may  be  detached  from  the 
femur  and  raised  toward  the  sacrum,  when  the 
branches  may  be  displayed  running  in  every 
direction  as  from  an  axis. 

The  situation  of  the  gluteal  artery  external  to 
the  pelvis  permits  the  trunk  of  the  vessel  to  be 
secured ;  the  gluteus  maximus  being  the  only 
muscle  by  which  it  is  covered,  it  may  be  exposed 
by  the  division  of  that  muscle;  the  situation  of 
the  artery  may  be  first  determined  "  by  drawing 
a  line  from  the  posterior  spinous  process  of  the 
ilium  to  the  miclspace  between  the  tuberosity  of 
the  ischium  and  the  great  trochanter;  if  we  divide 
this  line  into  three,  we  shall  find  the  gluteal 
artery  emerging  from  the  pelvis  at  the  juncture 
of  its  upper  and  middle  thirds."*  The  ligature 
of  this  artery  in  case  of  aneurism  has  been  very 
much  superseded  in  favour  of  that  of  the  inter- 
nal or  even  of  the  primitive  iliac,  the  latter  of 
which  has  been  tied  by  Guthrie  for  aneurism 
of  the  gluteal  artery  ;  the  propriety  of  this  pro- 
ceeding, however,  may  be  questioned ;  the 
ligature  of  either  the  internal  or  the  primitive 
iliac  must  be  regarded  a  more  serious  operation 
than  that  of  the  gluteal,  and  the  latter  has 
proved  so  efficacious  in  the  many  instances  in 
which  it  has  been  had  recourse  to,  that,  while 
it  is  practicable,  the  other  can  be  hardly  justi- 
fiable. 

3.  'The  ischiatic  artery  arises  from  the  ante- 
rior division  of  the  internal  iliac,  which,  after 
having  given  off  its  internal  branches,  divides 
into  two,  of  which  the  posterior  and  larger  is 
the  ischiatic  ;  it  is  the  second  in  size  of  the 
branches  of  the  iliac,  being  smaller  than  the 
gluteal;  but  in  the  adult  it  appears,  for  the 
most  part,  in-  direction  the  continuation  of  the 
original  vessel ;  its  course  within  the  pelvis  is 
long;  it  descends,  at  the  same  time  inclining 
forward,  and  forming  a  curve  convex  backward, 
toward  the  inferior  part  of  the  great  sciatic 
notch,  and  escapps  through  it  from  the  pelvis 
superior  to  the  sacro-sciatic  ligaments  and  infe- 
rior to  the  pyrifoimis  muscle;  it  then  descends 

*  Harrison. 

3  I 


834 


ILIAC  ARTERIES. 


behind  the  ischium  between  its  tuberosity  and 
the  great  trochanter  of  the  femur,  and  gives  off 
as  it  descends  numerous  branches  distributed 
in  the  superior  posterior  region  of  the  thigh. 
Within  the  pelvis  the  artery  is  situate  internal 
to  the  sacral  nerves  and  the  pyriformis  muscle, 
external  to  the  rectum  and  the  peritoneum,  in 
front  of  the  sacrum,  the  nerves  and  the  attach- 
ments of  the  pyriformis,  and  posterior  and  ex- 
ternal to  the  pudic  artery;  in  escaping  from  the 
cavity  it  passes  between  the  pyriformis  and 
ischio-coccygeus  muscles,  and  is  accompanied 
by  the  pudic  artery,  to  which  it  holds  the  same 
relation  as  before,  but  is  closer  to  it,  and  by  the 
sciatic  nerve ;  within  the  pelvis  it  is  internal 
and  anterior  to  the  sacral  plexus,  but  as  it  goes 
out  it  passes  between  its  branches,  and  thus 
becomes  posterior  to  the  nerve. 

Without  the  pelvis  the  ischiatic  artery  corre- 
sponds in  front  to  the  spinous  process  of  the 
ischium,  the  gemelli,  with  the  obturator  inter- 
nus  muscles,  and  the  quadratus  ;  posteriorly,  it 
is  covered  by  the  gluteus  maximus  and  the  inte- 
guments ;  it  is  situate  at  first  behind  the  sciatic 
nerve,  but  as  it  descends  it  becomes  internal  to 
the  nerve,  the  distance  between  them  increasing 
at  the  same  time.  While  behind  the  spinous 
process  of  the  ischium  the  ischiatic  artery  is 
external  to  the  pudic  artery,  and  more  super- 
ficial, i.e.  still  posterior;  butasthe  pudic  passes 
to  the  inside  of  the  tuberosity  of  the  bone,  while 
the  ischiatic  runs  on  its  outside,  the  two  vessels 
immediately  separate  and  cease  to  be  related. 

Within  the  pelvis  the  ischiatic  artery  gives 
some  irregular  and  small  branches  to  the  rec- 
tum, the  bladder,  the  uterus,  the  vagina,  the 
cellular  tissue,  the  pyriformis  and  levator  mus- 
cles ;  at  times  it  is  considered  as  giving  off 
also  the  pudic,  the  hemorrhoidal,  or  obturator 
arteries.  The  branches  which  it  furnishes  ex- 
ternal to  the  pelvis  are  numerous  ;  among  them 
are  distinguished  the  following  : — 1.  The  coccy- 
geal branch,  of  considerable  size,  runs  down- 
ward and  inward  toward  the  coccyx,  across  the 
pudic  artery  and  posterior  to  it,  passes  through 
the  great  sacro-sciatic  ligament,  and  divides  into 
branches,  which  are  distributed  to  the  ligament, 
to  the  gluteus,  the  coccygeus,  and  levator  ani 
muscles,  to  the  posterior  aspect  of  the  sacrum 
and  coccyx,  and  to  the  fat  and  integument ;  its 
branches  communicate  with  those  of  the  pudic. 
2.  A  considerable  branch  or  set  of  branches, 
which  run  outward  and  downward  toward  the 
back  of  the  great  trochanter  upon  the  internal 
obturator,  gemelli,  and  quadratus  muscles,  sup- 
ply them  with  branches,  and  anastomose  with 
the  circumflex  (femoral)  arteries.  3.  A  branch 
or  branches  to  the  inferior  part  of  the  gluteus 
maximus,  prolonged  through  it  to  its  insertion, 
and  then  meeting  the  circumflex  and  perforating 
arteries.  4.  A  branch  or  branches,  which 
attach  themselves  to  the  sciatic  nerve,  naturally 
of  small  size,  but  regular,  and  remarkable  for 
the  extraordinary  change  they  undergo  after  the 
interruption  of  the  main  artery  of  the  thigh; 
they  arise  about  the  tuberosity  of  the  ischium, 
and  descend  along  the  nerve  giving  it  branches, 
and  communicating  with  branches  from  the 
perforating  arteries,  which  also  attach  them- 


selves to  the  nerve,  whereby  a  chain  of  auasto- 
moses  is  established  along  it,  which,  when  the 
main  channel  has  been  interrupted,  becomes 
amazingly  enlarged  and  forms,  as  it  were,  one 
remarkably  tortuous  vessel  along  the  entire 
length  of  the  nerve.  6.  A  very  considerable 
branch,  the  termination  of  the  artery,  distri- 
buted to  the  upper  extremity  of  the  flexors  of 
the  leg,  the  biceps,  &c.  and  of  the  adductor 
muscles  ;  the  ramifications  of  which  communi- 
cate with  the  perforating  and  internal  circumflex 
arteries. 

The  ischiatic  artery  is  circumstanced  external 
to  the  pelvis  so  similarly  to  the  gluteal,  that,  if 
necessary,  it  might  be  exposed  during  life  by  a 
similar  operation  ;  for  a  mpthod  of  determining 
its  situation  prior  to  operation,  the  reader  is  re- 
ferred to  the  description  of  the  pudic  artery. 

4.  The  internal  pudic  artery  arises  from  the 
anterior  division  of  the  internal  iliac,  which  for 
the  most  part,  after  having  given  off  its  other 
branches,  divides  into  the  ischiatic  and  the 
pudic  ;  the  height  at  which  the  division  takes 
place  is  uncertain  ;  at  times  it  does  not  occur 
until  the  trunk  has  descended  to  the  sciatic 
notch,  or  even  escaped  from  the  pelvis.  The 
pudic  artery  is  smaller  than  the  sciatic;  it 
passes  downward,  forward,  and  inward,  until  it 
reaches  the  inferior  part  of  the  great  sciatic 
notch,  through  which  it  escapes  from  within 
the  pelvis  in  company  with  the  ischiatic  artery, 
the  pudic,  and  sciatic  nerves  ;  having  escaped 
from  the  pelvis  it  crosses  the  extremity  of  the 
spinous  process  of  the  ischium  and  the  attach- 
ment of  the  anterior  sacro-sciatic  ligament,  and 
returns  into  the  cavity  through  the  anterior 
notch,  accompanied  by  the  pudic  nerve  ;  having 
re-entered  the  pelvis,  it  then  runs  forward,  in- 
ward, and  downward  internal  to  the  tuberosity 
of  the  ischium,  until  it  reaches  its  anterior  ex- 
tremity, whence  it  continues  its  course  upward 
along  the  inside  of  the  rami  of  the  ischium  and 
pubis  toward  the  arch  of  the  pubis,  and  beneath 
the  latter  finally  divides  ;  the  course  of  the 
artery,  therefore,  forms  a  considerable  curve 
convex  downward  and  backward,  during  which 
the  vessel  is  contained  within  the  pelvis  at  its 
commencement  and  its  termination,  and  is 
without  the  cavity  during  the  intermediate  part. 
Its  course  is  thence  divided  into  three  stages, 
during  two  of  which  it  is  within,  and  in  the 
third  without  the  cavity. 

The  first  stage  of  the  artery's  course,  through- 
out which  it  is  contained  in  the  pelvis,  extends 
from  its  origin  to  the  lower  part  of  the  posterior 
sacro-sciatic  notch,  through  which  it  escapes 
from  the  cavity  ;  it  is  of  variable  length,  in  con- 
sequence of  the  variable  height  at  which  the 
vessel  arises.  The  relations  of  the  artery  during 
this  stage  are  posteriorly  and  externally  the 
sacral  nerves,  the  pyriform  muscle,  and  the 
sacrum ;  internally  the  peritoneum  and  the 
rectum  ;  it  is  posterior  and  external  to  the  fun- 
dus of  the  bladder  and  the  vesiculae  seminales, 
and  anterior  and  internal  to  the  ischiatic  artery ; 
previous  to  its  exit  it  sometimes  passes  between 
the  sacral  nerves  before  forming  the  plexus. 
It  goes  out  from  the  pelvis  below  the  pyriformis 
and  above  the  spinous  process  of  the  ischium 


ILIAC  ARTERIES. 


835 


and  the  anterior  sacro-sciatic  ligament,  passing 
between  the  pyriformis  and  the  ischio-coccygeus 
muscles,  and  having  the  ischiatic  artery  and 
sciatic  nerve  both  external  and  posterior  to  it. 
Its  second  stage  is  situate  without  the  pelvis  ; 
it  is  usually  its  shortest  one,  lasting  only  while 
the  artery  is  crossing  the  extremity  of  the 
spinous  process  of  the  ischium,  and  not  exceed- 
ing an  inch  in  length  ;  it  is  here  situate  behind 
and  above  the  spinous  process  and  the  anterior 
or  lesser  sciatic  ligament ;  it  is  covered  poste- 
riorly by  the  superior  edge  of  the  posterior  liga- 
ment and  by  the  gluteus  maximus  muscle  ;  it 
is  internal  to  both  the  ischiatic  artery  and 
sciatic  nerve,  and  it  is  crossed  posteriorly  by 
the  coccygean  branch  of  the  former. 

The  third  stage  of  the  artery  is  its  longest 
and  most  important  one ;  during  it  the  vessel 
is  situate  within  the  skeleton  of  the  pelvis, 
though  not  within  the  pelvis,  in  the  ordinary 
sense  of  the  phrase,  i.  e.  within  its  visceral  ca- 
vity, being  excluded  therefrom  by  the  struc- 
tures which  form  its  floor;  it  lies  along  the 
inside  of  the  tuberosity  of  the  ischium  and  the 
rami  of  the  ischium  and  pubis,  and  its  course  and 
relations  being  different  at  the  posterior  and  an- 
terior parts  of  the  stage,  they  may  with  advan- 
tage be  considered  separately.  In  the  posterior 
part,  or  as  far  forward  as  the  anterior  extremity 
of  the  tuberosity  or  the  base  of  the  triangular 
ligament  of  the  perinaeum,  the  artery  descends  ; 
in  the  anterior  it  ascends;  in  the  posterior  it  is 
situate  in  the  outer  wall  of  the  space  which  in- 
tervenes between  the  inside  of  the  tuberosity  of 
the  ischium  and  the  rectum — the  ischiorectal 
space.  This  space  is  cuneiform,  its  base  below, 
toward  the  surface  ;  its  apex  above,  toward  the 
pelvis ;  its  inner  wall  is  formed  by  the  levator  ani 
and  the  dense  thin  expansion  by  which  the  mus- 
cle is  covered  externally  or  inferiorly,  its  outer 
by  the  obturator  fascia  attached  inferiorly  to  the 
edge  of  the  great  sacro-sciatic  ligament  and  of  its 
falciform  process,  and  by  the  obturator  muscle : 
the  space  is  occupied  by  a  mass  of  adipose  cel- 
lular structure,  traversed  by  some  branches  of 
the  pudic  vessels  and  nerves.  In  a  canal  in 
the  obturator  fascia  the  artery  is  contained 
through  the  posterior  part  of  the  third  stage  ;  by 
some  it  is  maintained  to  be  between  the  fascia 
and  the  muscle,  in  a  sort  of  canal  formed  inter- 
nally by  the  fascia,  externally  by  the  muscle 
and  tuberosity,  and  inferiorly  by  the  great 
sciatic  ligament ;  but  this  is  not  correct ;  the 
vessel  being  in  the  fascia,  and  not  external  to 
it ;  the  line  of  its  course  is  convex  downward, 
about  an  inch  and  a  half  from  the  under  Surface 
of  the  tuberosity  of  the  ischium  at  its  most  de^- 
pending  part,  and  from  two  to  two  and  a  half 
inches  from  the  surface,  this  distance  varying  of 
course  according  to  the  condition  of  the  sub- 
ject ;  the  line  approaches  the  margin  of  the 
ramus  or  the  spinous  process,  thence  forward 
or  backward.  In  the  anterior  part  of  the  stage 
the  vessel  is  enclosed  in  the  triangular  ligament 
along  its  attachment  to  the  bone;  consequently, 
it  is  separated  from  the  surface  by  the  superfi- 
cial stratum  of  this  structure  first,  in  the  second 
place  by  the  eras  penis,  covered  by  the  ischio- 
cavernous muscle,  and  behind  it  by  the  trans* 


versus  perinei  muscle ;  and  lastly,  by  the  super- 
ficial structures  of  the  perineum.  As  the  artery 
proceeds  it  becomes  more  superficial,  and  finally 
emerges  from  the  triangular  ligament,  beneath 
the  subpubic  ligament,  as  the  dorsal  artery  of 
the  penis. 

It  is  in  its  third  stage  that  the  pudic  artery 
is  exposed  to  danger  in  the  lateral  operation  of 
lithotomy ;  it  may  be  wounded  in  either  of  the 
two  steps  of  dividing  the  urethra  and  prostate 
or  the  subsequent  division  of  the  superficial 
structures :  in  the  former  case,  the  danger  of 
the  accident  will  be  greatest  when  the  section  is 
effected  with  the  scalpel  or  gorget,  and  in  pro- 
portion to  the  width  of  the  blade,  and  the  de* 
gree  to  which  the  cutting  edge  may  be  directed 
outward,  will  the  clanger  be  enhanced  ;  in  the 
second,  the  risk  will  be  alike  with  all  cutting 
instruments,  and  will  be  determined  by  the 
width  of  the  blade,  the  attention  paid  to  a  pro- 
per degree  of  lateralization,  the  manner  in 
which  the  instrument  is  made  to  effect  a  divi^ 
sion  of  the  parts,  and  the  extent  of  the  section. 
The  branches  of  the  pudic  artery  are  numerous, 
and  may  be  conveniently  arranged  according  to 
the  stage  of  its  course,  in  which  they  are  given 
off.  In  its  first,  before  its  exit  from  the  pelvis, 
it  gives  branches  to  the  bladder,  the  rectum, 
the  vesiculae,  prostate,  vagina,  and  uterus ;  it 
also  frequently  furnishes  the  middle  hemor- 
rhoidal. 

In  its  second  stage,  while  external  to  the 
pelvis,  it  gives  branches  to  the  gluteus,  the  pyri' 
formis,  the  obturator  and  gemelli  muscles,  the 
sacro-sciatic  ligament,  the  ischium,  and  sacrum  ; 
they  anastomose  with  the  ischiatic,  the  gluteal, 
and  internal  circumflex  arteries. 

Those  which  arise  in  its  third  stage  are  the 
most  important.  1.  The  artery  gives,  while  on 
the  inside  of  the  tuberosity  of  the  ischium, 
branches  which  are  distinguished  into  external 
and  internal ;  the  former  are  small,  and  go  to 
the  adipose  structure  beneath  the  tuberosity,  to 
the  attachment  of  the  biceps,  to  the  obturator 
intern  us,  and  the  integuments  :  the  internal  are 
larger  ;  they  come  through  the  obturator  fascia, 
run  inward  toward  the  anus,  and  are  distributed 
to  the  adipose  cellular  structure  of  the  ischio- 
rectal space,  to  the  levator  and  sphincter  ani,  to 
the  extremity  of  the  rectum,  and  the  margin  of 
the  anus;  they  anastomose  with  branches  of 
the  middle  hemorrhoidal  artery  and  with  those 
of  the  other  side  :  they  are  variable  in  number, 
being  one,  two,  or  three,  and  are  denominated 
"  external  hemorrhoidal ;"  they  are  liable  to  be 
divided  in  operations  in  the  vicinity  of  the 
anus,  e.  g.  in  the  superficial  incision  in  the 
lateral  operation  or  in  operation  for  fistula ; 
they  are,  however,  so  small  that  they  seldom 
give  trouble,  either  ceasing  to  bleed  spontane- 
ously, or  being  commanded  by  brief  compress 
sion. 

2.  The  perineal  artery. — At  a  short  distance 
from  the  base  of  the  triangular  ligament  the 
pudic  gives  off  a  branch  of  considerable  size 
and  length,  by  many  regarded  as  one  of  its 
ultimate  branches  ;  the  pudic,  according  to 
them,  terminating  by  dividing  into  two  branches, 
an  inferior,  "  the  perineal,"  and  a  superior 

3  I  2 


83G 


ILIAC  ARTERIES. 


The  perineal  artery  comes  through  the  obtu- 
rator fascia,  and  descends  to  the  perineum,  pos- 
terior to  the  transverse  muscle,  though  at  tunes 
before  it;  when  it  has  got  below  the  muscle  it 
changes  its  direction,  and  runs  forward,  up- 
ward, and  inward,  superficial  to  the  triangular 
ligament,  toward  the  root  of  the  scrotum;  at 
this  part  of  its  course  it  is  situate  along  the 
outer  side  of  the  interval  which  separates  the 
cms  penis  and  the  corpus  spongiosum  urethra?, 
internal  and  parallel  to  the  eras,  and  covered 
by  a  superficial  lamina  of  the  fascia  of  the  peri- 
neum, a  deeper  layer  of  which  intervenes  be- 
tween it  and  the  muscles  of  the  crus  and  bulb 
and  the  triangular  ligament ;  as  it  proceeds  it 
gives  the  following  branches  :  1.  outward,  one 
to  the  integument  and  subcutaneous  structure 
beneath  the  anterior  part  of  the  tuberosity  of 
the  ischium  ;  2.  inward,  one  which  runs  to  the 
interval  between  the  front  of  the  rectum  and 
the  bulb  of  the  corpus  spongiosum,  superficial 
and  parallel  to  the  transverse  muscle  ;  it  sup- 
plies the  integument  and  subcutaneous  struc- 
ture of  the  perineum,  and  the  common  inser- 
tion of  the  superficial  sphincter,  the  transverse 
muscle,  the  bulbo-cavernous  and  the  levator  ani 
in  front  of  the  rectum.  This  branch  is  at  times 
furnished  by  the  pudic  itself ;  it  is  denominated 
by  some  "  the  proper  perineal,"  by  others  "  the 
transverse  perineal."  3.  A  branch  to  the  bulbo- 
cavernous ;  4.  one  to  the  ischio-cavernous  mus- 
cles. 

The  perineal  artery  having  reached  the  back 
of  the  scrotum  sends  long  branches  into  the 
subcutaneous  structure  and  integument  of  that 
part,  and  entering  the  septum  scroti,  terminates 
in  it  as  the  "  artery  of  the  septum."  In  the 
female,  the  ultimate  branches  of  the  artery  are 
distributed  to  the  labia  majora. 

The  perineal  artery,  from  its  superficial  situa- 
tion, is  exposed  to  be  divided  on  many  occa- 
sions;  in  lateral  lithotomy  it  may  be  cut,  but 
for  the  most  part  it  escapes,  its  course  being 
external  to  the  line  of  incision ;  some  of  its 
branches,  however,  cannot  escape,  the  trans- 
verse perineal  particularly  must,  as  a  matter  of 
course,  be  divided.  Having  given  off  the  peri- 
neal artery,  the  pudic  pursues  its  course,  en- 
closed in  the  triangular  ligament,  along  the 
rami  of  the  ischium  and  pubis,  toward  the  arch 
of  the  pubis ;  arrived  under  cover  of  the  crus 
penis,  it  gives  off  a  considerable  branch,  des- 
tined principally  for  the  urethra  and  the  corpus 
spongiosum,  and  denominated  hence  by  Chaus- 
sier  "  urethro-bulbaire,"  by  Harrison  "arteria 
corporis  bulbosi  vel  spongiosi  urethra,"  but  by 
Boyer  and  Cloquet  "  artere  transverse ;"  it  is 
short,  runs  transversely  inward,  enclosed  in  the 
triangular  ligament  about  a  quarter  of  an  inch 
from  its  base,  but  nearer  to  it  externally  than 
internally;  at  the  bulb  it  divides  into  two 
parts,  of  which  one,  the  smaller,  is  distributed 
to  the  ante-prostatic  gland  ;  the  other  enters  the 
bulb  and  ramifies  through  its  vascular  struc- 
ture, being  prolonged  through  it  as  far  as  the 
glans,  supplying  at  the  same  time  the  mem- 
brane of  the  urethra  and  its  lacuna? ;  a  branch 
from  it  passes  into  the  corpus  cavernosum,  and 
anastomoses  with  the  artery  of  that  structure. 


In  the  female,  the  branch  corresponding  to  this 
is  distributed  to  the  vascular  plexus  which  sur- 
rounds the  orifice  of  the  vagina. 

The  artery  of  the  bulb  is  one  of  much  prac- 
tical importance  ;  it  is  liable  to  be  wounded  in 
lithotomy  in  the  act  of  opening  the  urethra; 
this  accident  is  incurred  when  the  canal  is 
opened  too  high,  i.  e.  too  near  to  the  arch  of 
the  pubis,  or  too  much  from  the  side  rather 
than  from  beneath,  and  in  either  case  is  pretty 
certain  to  occur ;  the  proceeding  by  which  to 
avoid  both  the  artery  and  the  bulb  itself,  is  to 
cut  into  the  urethra  as  far  back,  i.  e.  from  the 
surface,  and  as  far  from  the  arch  as  the  gui- 
dance of  the  staff  will  assure  the  operator  to  be 
safe,  the  point  of  the  knife  being  directed  as 
much  from  below  as  the  interference  of  the 
bulb  and  the  lateral  line  of  incision  will  permit; 
further,  it  is  the  design  of  the  operator  to  open 
the  canal  in  the  membranous  portion  and  be- 
hind the  bulb;  and  in  order  to  effect  this,  the 
incision  should  be  made  as  near  as  may  be  to 
the  base  of  the  triangular  ligament,  or,  if  possi- 
ble, behind  it.  If  divided,  the  artery  of  the 
bulb  may  be  tied,  though  not  without  some 
difficulty  ;  it  is  prevented  from  retracting  by 
being  enc'osed  in  the  triangular  ligament,  but 
it  is  situate  deep;  its  distance  from  the  anterior 
surface  of  the  ramus  of  the  pubis  being  about 
three-fourths  of  an  inch  ;  its  shortness  as  well 
as  its  being  concealed  by  the  crus  penis  and 
by  the  bulb  with  their  muscles,  and  being  in 
the  superior  angle  of  the  wound,  must  also 
increase  the  difficulty  of  securing  it. 

The  pudic  artery  having  reached  the  base  of 
the  subpubic  ligament  divides  into  its  two 
final  branches,  the  artery  of  the  corpus  caverno- 
sum and  the  dorsal  artery  of  the  penis. 

3.  The  artery  of  the  corpus  cavernosum  arises 
from  the  pudic  between  the  crus  penis  and  the 
ramus  of  the  pubis  and  immediately  enters  the 
crus  obliquely ;  it  is  prolonged  through  the 
vascular  tissue  of  the  corpus  cavernosum  to  its 
extremity,  distributing  branches  to  either  side, 
and  communicating  with  that  of  the  other. 
For  the  peculiar  distribution  of  the  arteries  of 
the  corpus  cavernosum  and  spongiosum, accord- 
ing to  Miiller,  see  the  article  EhectileTissue. 

4.  The  dorsal  artery  of  the  penis,  which  ap- 
pears indirection  the  continuation  of  the  original 
vessel,  comes  through  the  triangular  ligament 
and  ascends  in  front  of  the  subpubic  ligament 
through  the  angle  formed  by  the  crura  penis  at 
their  junction  ;  having  surmounted  the  crus  it 
attaches  itself  to  the  dorsal  aspect  of  the  penis 
and  runs  forward  upon  it  on  either  side  of  the 
suspensory  ligament  parallel  to  the  artery  of 
the  other  side,  and  contained  together  with  it, 
the  dorsal  vein,  and  nerves,  in  the  groove 
formed  by  the  apposition  of  the  crura,  internal 
to  the  nerve  and  external  to  the  vein;  it  is 
prolonged  to  the  anterior  extremity  of  the 
corpus  cavernosum,  where  it  breaks  up  into 
branches,  which  uniting  with  those  of  the  other 
form  an  arterial  zone  behind  the  corona  glandis, 
and  sinking  into  the  glans  are  distributed  to  its 
tissue. 

During  their  course  along  the  dorsum  of  the 
penis  the  arteries  are  tortuous,  communicate 


ILIAC  ARTERIES. 


frequently,  are  covered  not  only  by  the  skin 
and  subcutaneous  cellular  structure,  but  also 
by  a  dense  filamentary  expansion,  or  fascia, 
which  invests  the  penis  beneath  them,  and  they 
give  branches  to  those  structures  as  also  to  the 
fibrous  membrane  of  the  corpus  cavernosum, 
and  finally  to  the  prepuce.  The  dorsal  artery 
is  at  times  furnished  by  the  obturator,  or  the 
external  pudic  artery. 

Beside  the  varieties  of  origin  which  have 
been  mentioned,  the  pudic  presents  some  im- 
portant varieties  in  its  course.  It  has  been 
found  by  Burns  in  four  instances,  "  instead 
of  passing  out  of  the  pelvis  between  the 
sacro-sciatic  ligaments  to  attach  itself  to  the 
lateral  and  inferior  part  of  the  bladder,  and  to 
traverse  the  upper  segment  of  the  prostate 
gland  in  its  course  to  the  ramus  of  the  ischium." 
Another  variety  is  described  by  Harrison,  in 
which  the  proper  trunk  of  the  pudic  is  found 
unusually  small,  and  the  dorsal  artery  of  the 
penis  arises  originally  and  separately  from  the 
internal  iliac, 'runs  along  the  side  of  the  bladder 
and  prostate  gland,  and  escapes  from  the 
pelvis  along  with  the  dorsal  vein  of  the  penis 
beneath  the  arch  of  the  pubis.  The  latter  dis- 
position, mutatis  mutandis,  has  been  found  by 
Tiedemann  in  the  female  as  well  as  m  the 
male,  and  is  figured  in  his  thirtieth  plate.  It  is 
described  by  Winslow  as  the  normal  arrange- 
ment, only  thataccording  to  him  the  vessel,  which 
takes  this  unusual  course,  arises  sometimes 
from  the  common  pudic,  at  others  from  the 
iliac.  Haller  questions  the  occurrence  of  this 
disposition,  but  describes  another,  in  which 
the  inferior  vesical  artery  arising  from  the 
middle  hemorrhoidal  is  continued  on  the 
dorsum  of  the  prostate  into  the  dorsal  artery  of 
the  penis,  given,  as  in  ordinary,  from  the  pudic. 

Among  the  varieties  of  the  arterial  system 
few  possess  greater  interest  than  these,  inas- 
much as  no  foresight  or  skill  can  guard  against 
the  untoward  accidents  which  attend  their 
presence  in  lithotomy  ;  their  possibility  forbids 
a  section  of  the  prostate  upward ;  but  for- 
tunately they  are  rare. 

The  situation  of  the  pudic  artery  upon  the 
exterior  of  the  pelvis  admits  the  possibility  of 
tying  the  vessel  in  the  living  subject;  the 
plan  of  operation  necessary  for  the  purpose 
is  similar  to  that  to  be  adopted  with  the  gluteal 
artery,  only  it  must  be  performed  lower  down  ; 
it  is  the  same  with  that  for  the  ischiatic  artery; 
for  determining  the  situation  of  which  or  the 
pudic  the  following  directions  are  given  by 
Harrison  :*— "  Place  the  individual  on  his  face 
with  the  lower  extremity  extended  and  tire  toes 
turned  inwards:  feel  for  the  summit  of  the 
great  trochanter,  and  for  the  base  or  articulated 
end  of  the  coccyx  ;  these  two  points  are  on  a 
level ;  then  draw  a  line  from  one  to  the  other, 
and  we  may  be  certain  that  the  pudic  artery 
and  the  spine  of  the  ischium  are  opposite  the 
junction  of  the  middle  and  internal  thirds  of 
this  line."  The  ischiatic  artery  may  be 
reached  as  easily,  or  even  more  so,  than  the 

*  Vol.  ii.  p.  103. 


837 


gluteal ;  but  the  difficulty  which  must  attend 
the  seeking  for  the  pudic  must  be  extreme. 

The  external  iliac  artery,  (arteria 
iliaca  externa,  Lat. ;  arttrc  iliaque  externe, 
Fr. ;  portion  iliaque  dc  la  erurale,  Chauss. ; 
Aussere  Iiuft-puhader,  Ger.)  is  the  vessel 
destined  for  the  supply  of  the  lower  extremity, 
of  which  the  portion  contained  within  the 
abdomen,  in  the  iliac  region,  is  denominated  the 
"  external "  iliac,  in  contradistinction  to  the 
artery  of  the  pelvis,  the  "  internal." 

It  commences  at  the  division  of  the  primi- 
tive iliac  artery,  at  a  point  intermediate  to  the 
body  of  the  last  lumbar  vertebra,  or  the  sacro- 
vertebral  prominence,  and  the  sacro-iliac  articu- 
lation, and  it  terminates  at  the  crural  arch,  at 
a  point  midway  between  the  superior  anterior 
spinous  process  of  the  ilium  and  the  spinous 
process  of  the  pubis,*  or  at  the  outer  side  of 
the  ilio-pectineal  eminence  of  the  os  innomina- 
tum.  The  point  at  which  the  vessel  com- 
mences is  not  uniform  either  in  all  subjects  or 
on  the  two  sides  of  the  same;  depending  upon 
the  point  at  which  the  primitive  iliac  divides, 
which  is  variable,  it  will  be  higher  or  lower, 
nearer  to  the  vertebra  or  to  the  articulation, 
according  to  the  situation  of  the  bifurcation  of 
that  vessel :  on  the  right  side  of  the  body  the 
artery  commences  for  the  most  part  nearer  to 
the  body  of  the  vertebra  than  on  the  left,  on 
which  it  is  of  course  nearer  to  the  articulation  ; 
hence  the  artery  arising  higher  upon  the  former 
is  longer  upon  that  side  than  upon  the  latter, 
the  difference  in  length  varying  from  a  quarter 
to  half  an  inch.  The  external  iliac  terminates 
in  the  femoral  or  crural  artery,  strictly  so 
called  ;  but  the  distinction  between  the  two  is 
one  only  of  convenience,  inasmuch  as  they  are 
but  different  stages  of  the  same  vessel ;  there 
appears  therefore    much    propriety    in  the 

*  The  situation  of  the  artery  at  its  termination  is 
differently  stated  by  different  writers  ;  Boyer  states 
it  to  be  midway  between  the  spinous  proeess  of  the 
ilium  and  the  symphysis  pubis;  Cloquet,  midway 
between  t lie  spine  of  the  ilium  and  the  spinous  pro- 
cess of  the  pubis  ;  Harrison,  about  half  an  inch  to 
the  pubic  side  of  the  centre  of  the  crural  arch.  The 
relation  of  the  vessel  to  the  points  between  which 
it  is  placed,  is  probably  not  the  same  in  all  cases; 
but  that  assigned  to  it  by  Cloquet  seems  most 
generally  applicable.  According  to  Cooper,  with 
whom  Cloquet  concurs,  there  are,  in  the  male, 
3^  inches  from  the  symphysis  pubis  to  the 
middle  of  the  artery,  and  in  the  female  3|, 
while  the  distance  to  the  superior  anterior  spinous 
process  of  the  ilium  is  in  the  former  53.,  and  in 
the  latter  six  inches  ;  the  artery  must  therefore  ba 
external  to  the  mid-point,  being  for  the  most  part 
concave  forward  and  inward  above,  and  convex 
forward  below  ;  but  in  this  particular  it  is  not  uni- 
form, being  sometimes  nearly  straight ;  the  degreo 
of  its  tortuosity  also  appears  to  depend  upon  the 
age  of  the  subject  and  the  plenitude  of  the  vessel. 
The  direction  of  the  artery  is  oblique,  and  as  the 
primitive  iliac  and  it  are  continuous  in  the  adult,  the 
course  of  both  the  vessels  maybe  defined,  during 
life,  by  a  line  extending  from  the  umbilicus,  or 
from  half  an  inch  below  it,  at  its  left  side,  to  a  point 
midway  between  the  superior  anterior  spinous  pro- 
cess of  the  ilium  and  the  spinous  process  of  the 
pubis,  the  upper  extremity  of  the  line  varying 
according  to  the  situation  at  which  the  aorta  divides. 


833 


ILIAC  ARTERIES. 


designation  adopted  by  Chaussier,  which, 
while  it  recognises  the  identity  of  the  vessel 
throughout  its  course,  sufficiently  marks  the 
grounds  of  distinction  between  its  two  portions. 
The  external  is  somewhat  smaller  than  the 
primitive  iliac,  but  in  the  adult  considerably 
larger  than  the  internal  ;  its  direction  is  down- 
ward, outward,  and  forward,  and  hence  it 
forms  with  the  primitive  iliac  a  curve  convex 
backward,  and  seems  the  continuation  of  that 
vessel ;  its  length  is  from  three  to  four  inches, 
and  during  its  course  it  forms  one  or  more 
Curvatures. 

Such  is  the  disposition  of  the  vessel  in  the 
adult;  but  in  the  younger  subject  it  is  different 
in  some  respects;  in  the  foetus  the  external  iliac 
is  considerably  smaller  than  the  internal,  and 
does  not  seem  the  continuation  of  the  primitive 
iliac,  which  at  that  epoch  is  continued  into  the 
internal ;  the  external  appearing  rather  as  a 
branch  or  a  smaller  division  from  a  trunk 
common  to  the  other  two  ;  after  birth  the 
relative  disposition  of  the  iliacs  gradually 
changes,  until  they  acquire  that  of  the  adult. 

The  relations  of  the  external  iliac  artery  are 
as  follows  ;  posteriorly,  it  corresponds  through 
the  upper  half  of  its  course  to  the  lateral  part 
of  the  superior  aperture  of  the  pelvis;  inclining 
outwards  as  it  descends,  it  corresponds  in  its 
lower  half  to  the  os  innominatum,  and  the  more 
perfectly,  the  nearer  it  approaches  the  crural 
arch,  at  which  part  it  is  placed  in  front  of  the 
bone,  crossing  it  nearly  at  right  angles,  and 
separated  from  it  by  an  interval  occupied  by 
the  psoo-iliac  aponeurosis  and  the  psoas  muscle. 

At  its  outset  the  external  iliac  vein  is  directly 
behind  the  artery,  and  on  its  right  side,  also 
the  commencement  of  the  primitive  iliac  vein, 
the  artery  crossing  the  junction  of  the  two 
vessels,  on  that  side,  obliquely  in  its  descent; 
during-  the  remainder  of  its  course,  the  vein, 
though  posterior  to  it,  is  also  internal ;  through- 
out the  lower  half  of  its  course  it  lies  upon 
the  psoo-iliac  aponeurosis,  supported  by  the  os 
innominatum,  and  at  first  separated  from  the 
bone  only  by  the  aponeurosis ;  but  as  it  pro- 
ceeds separated  from  it  also  by  the  tendon  of  the 
psoas  parvus  when  present,  and  by  the  inner  mar- 
gin of  the  psoas  magnus,  it  is  very  near  to  the  os 
innominatum,  external  to  the  ilio-pectineal  emi- 
nence, and  being  here  supported  by  bone,  and 
made  steady  by  its  connections  it  may  with 
certainty  be  compressed  and  its  circulation 
perfectly  commanded.  Internally,  the  artery 
corresponds  above  to  the  aperture  of  the  pelvis, 
to  its  viscera  more  or  less  intimately,  according 
to  their  state  of  distension  or  contraction,  and 
also  to  the  small  intestines  which  descend  into 
it ;  in  the  lower  half  of  its  course,  the  external 
iliac  vein,  which  at  its  outset  is  behind  or 
beneath  the  artery,  is  internal,  though  still  some- 
what posterior  to  it  ;at  the  crural  arch  the  artery 
and  vein  are  nearly  upon  the  same  level,  being 
supported  by  the  os  innominatum  ;  the  artery 
however  somewhat  anterior  to  the  vein,  but 
as  the  vein  recedes  from  the  arch  it  inclines 
less  inward  than  the  artery,  and  at  the  same 
time  retreats  more  from  the  surface;  and  hence 


it  gradually  gets  more  completely  behind  the 
artery  until  at  its  junction  with  the  primitive 
vein  it  is  concealed  by  it  anteriorly. 

The  artery  is  covered  by  peritoneum,  upon 
its  inner  side  through  a  considerable  part  of  its 
course ;  above  the  membrane  covers  it  com- 
pletely ;  but  as  it  descends  the  extent  becomes 
less  in  consequence  of  the  ascent  of  the  vein  ; 
which  thus  gradually  intervenes  between  the 
artery  and  the  membrane,  and  removes  the 
latter  from  it  altogether  in  the  lower  part  of  its 
course.  When  the  primitive  iliac  divides  at  a 
high  point,  the  ureter  descends  into  the  pelvis 
internal  to  the  external  iliac  immediately  after 
its  origin ;  this  occurs  more  frequently  upon  the 
right  side  than  the  left.  Beneath  the  perito- 
neum the  artery  is  covered  by  an  investment,  of 
which  presently  again,  attaching  it  superiorly 
to  the  peritoneum  and  inferiorly  to  the  vein. 

Externally  the  artery  corresponds  through  its 
entire  course  to  the  psoas  magnus  muscle,  but 
it  is  separated  from  it  by  the  psoo-iliac  fascia,  to 
which  it  is  connected  by  its  immediate  invest- 
ment ;  the  relation  of  the  artery  and  the 
muscle  are,  however,  somewhat  different  at  the 
upper  and  lower  parts  of  the  vessel's  course; 
above,  the  artery  does  not  lie  upon  the  muscle, 
but  rests  against  its  inner  side  along  its  anterior 
part,  while  inferiorly  it  lies  upon  the  inner 
margin  of  the  muscle  at  the  same  time  that  it 
rests  against  it  externally. 

The  genito-crural  nerve  is  situate  along  the 
outer  side  of  the  artery;  this  nerve,  long  and 
slender,a  branch  of  the  lumbar  plexus,  descends 
upon  the  psoas,  extenal  to  the  artery,  and  at 
first  at  a  little  distance  from  it ;  as  it  proceeds,  it 
approaches  thevessel,andliesclosetoitenveloped 
in  the  fascia  propria;  at  the  lower  part  of  its  course 
its  genital  branch  frequently  passes  in  front 
of  the  artery.  The  anterior  crural  vein  is  also 
external  to  the  artery ;  but  it  is  considerably 
posterior  to  it,  separated  from  it  by  the  outer 
margin  of  the  psoas,  between  which  and  the 
iliacus  it  lies,  and  also  by  the  fascia  iliaca,  which 
covers  it ;  the  nerve  is  about  half  an  inch  from 
the  artery  at  the  crural  arch ;  as  it  recedes  from 
the  arch  the  distance  increases. 

In  front,  the  artery  is  covered  immediately 
by  a  cellular  investment,  formed  by  the  sub- 
peritoneal cellular  structure — -the  fascia  propria 
—  upon  the  posterior  wall  of  the  iliac  fossa; 
this  encloses  both  the  artery  and  the  vein  and  at 
the  same  time  connects  them ;  it  varies  in  its 
condition  according  to  the  subject,  in  some  it 
appears  a  dense,  but  still  cellular  expansion,  in 
others  from  the  deposition  of  fat  it  forms 
an  adipose  stratum,  which  however  still  presents 
a  more  condensed  character  in  immediate  con- 
tact with  the  vessels  ;  it  adheres  closely  to  the 
surface  of  the  fascia  iliaca  upon  either  side  of 
the  vessels  and  thus  attaches  them  to  it;  it  is 
prolonged  upward  upon  the  primitive  iliac 
vessels,  and  below,  it  ascends  between  the 
peritoneum  and  the  fascia  transversalis  upon 
the  anterior  abdominal  wall ;  upon  the  primi- 
tive iliac  it  is  very  thin  and  proportionally 
weak  ;  but  as  it  descends  it  increases  in  thick- 
ness and  strength  until  at  the  lower  part  of  the 


ILIAC  ARTERIES. 


839 


external  iliac.  It  forms  a  stratum  of  some 
thickness  and  considerable  resistance,  deserving 
of  much  attention  in  a  practical  point  of  view; 
there  are  imbedded  in  it  immediately  above  the 
crural  arch,  and  superficial  to  the  artery,  one  or 
more  lymphatic  glands;  the  genito-erural  nerve 
also  descends  enclosed  in  this  structure,  at  the 
outside  of  the  artery.  Beneath  the  investment, 
and  immediately  above  the  crural  arch,  an  ex- 
pansion of  limited  extent,  presenting  frequently 
a  true  fibrous  or  aponeurotic  character,  arises 
from  the  front  of  the  vessels,  and  passing 
forward  becomes  identified  with  the  fascia 
transversalis  upon  its  internal  surface;  thus 
connecting  the  vessels  to  the  anterior  part  of  the 
superior  aperture  of  the  femoral  sheath,  and 
closing  the  interval  between  these  parts,  which 
otherwise  would  be  unguarded. 

In  the  second  place  the  artery  is  covered 
anteriorly  through  about  four-fifths  of  its  course 
by  the  peritoneum  of  the  iliac  fossa  ;  in  the 
inferior  fifth,  i.e.,  for  from  half  to  three-fourths 
of  an  inch  immediately  above  the  crural  arch, 
the  membrane  passing  from  the  front  of  the 
artery  to  the  anterior  wall  of  the  abdomen 
leaves  the  iliac  artery  uncovered;  and  hence 
the  practical  inference  that  the  external  iliac 
artery  may  be  tied  without  disturbing  the 
peritoneum. 

Beneath  the  peritoneum  the  artery  is  crossed 
at  the  inferior  part  of  its  course  by  the  sper- 
matic vessels,  and  at  the  superior,  upon  the 
right  side  very  frequently  by  the  ureter. 

Thirdly,  the  viscera  of  the  iliac  fossa  on  the 
one  hand,  or  of  the  pelvis  on  the  other,  ac- 
cording to  circumstances,  cross  or  overlap  it ; 
on  the  right,  the  ccecum  and  the  termination 
of  the  ileum  ;  on  the  left,  the  sigmoid  flexure 
and  the  commencement  of  the  rectum,  and  on 
both  sides  the  small  intestines  are  placed  in  front 
of  it.  And  when  the  viscera  of  the  pelvis  become 
distended  and  rise  from  the  cavity  they  overlap 
it  from  that  side. 

The  third  relation  of  the  artery  in  front  is 
the  anterior  wall  of  the  iliac  region  ;  the  details 
of  this  it  is  not  proposed  to  examine  at  length, 
but  only  so  far  as  they  may  be  concerned  in 
the  relations  of  the  artery  ;  the  structures  com- 
posing the  wall  being  numerous,  they  may  be 
conveniently  arranged  into  three  sets,  viz.,  the 
superficial,  the  intermediate,  and  the  deep  or 
lining  structures. 

The  superficial  structures  are  three,  the 
skin,  the  subcutaneous  cellular  tissue,  and  the 
fascia.  Of  these  the  first  does  not  require  to 
be  dwelt  upon  ;  the  second  is  subject  to  much 
variety  in  its  condition  ;  it  forms  a  stratum  of 
considerable  thickness  in  every  case  ;  when, 
however,  the  superficial  cellular  structure  of 
the  body  is  charged  with  much  adeps,  it  then 
forms  an  uniform  and  thick  stratum  of  fat 
without  any  distinction  into  lamina;;  this  is 
best  exemplified  at  the  early  periods  of  life, 
particularly  in  children  cut  off  by  an  acute 
disease;  when,  on  the  contrary,  the  body  is 
emaciated,  it  forms  a  condensed  cellular  ex- 
pansion much  thinner  than  in  the  former  case, 
and  divisible  frequently  into  laminoe.  This 
structure  is  continued  from  the  iliac  over  the 


other  regions  of  the  abdomen,  downward  upon 
the  thigh,  and  in  the  middle  line  upon  the 
spermatic  process  of  the  male  and  the  organs 
of  generation.  Numerous  superficial  vessels 
are  contained  in  and  ramify  through  it;  these 
are  derived  from  several  sources,  but  that  which 
is  proper  to  the  iliac  region  is  the  superficial 
epigastric  artery  which  ascends  from  the 
femoral  superficial  to  the  aponeurosis  of  the 
external  oblique  muscle  and  intermediate  to 
the  inguinal  rings. 

Beneath  the  subcutaneous  stratum  is  the 
third  superficial  structure,  the  fascia  ;  this  is  a 
thin  dense  expansion  by  which  the  external 
oblique  muscle  and  its  aponeurosis  are  covered  ; 
it  is  not  confined  to  the  abdomen,  but  is  con- 
tinued into  a  similar  expansion  upon  the  ad- 
joining regions  whether  upward  or  downward  ; 
it  adheres  closely  to  the  muscular  portion  of 
the  oblique,  particularly  at  the  junction  of  the 
muscular  fibres  with  the  aponeurosis  along  the 
linea  semilunaris,  but  its  connection  to  the 
aponeurosis  itself  is  more  free,  an  extensible 
and  delicate  cellular  tissue  being  interposed. 
Hence  it  is  easily  detached  from  the  latter;  it 
is  most  dense,  fibrous,  and  strong  upon  the 
iliac  region  ;  as  it  ascends  thence  it  becomes 
less  dense  and  fibrous,  and  assumes  more  of  a 
simply  condensed  cellular  character;  it  is  not 
equally  distinct  in  every  subject,  in  all  it  can 
be  recognized  at  the  crural  arch,  and  for  some 
distance  above  it,  but  as  it  recedes  from  the 
arch  it  frequently  seems  to  be  gradually  re- 
solved and  to  cease.  Below,  it  is  attached 
posteriorly  to  the  outer  edge  of  the  crest  of  the 
ilium,  and  along  this  line  it  meets  the  insertion 
of  the  fascia  lata  of  the  bock  of  the  thigh  ;  in 
front  between  the  superior  anterior  spinous 
process  of  the  ilium  and  the  spinous  process  of 
the  pubis  it  descends  over  the  crural  arch,  having 
only  a  cellular  connection  to  it,  and  being 
separable  with  ease  from  it,  as  well  as  from 
the  aponeurosis  of  the  oblique  ;  immediately 
below  the  arch  it  is  united  to  the  superficial 
surface  of  the  fascia  of  the  thigh,  both  externally 
and  internally,  on  the  latter  side  passing  back 
to  the  pectineal  line  of  the  pubis,  into  which  it 
is  inserted  along  with  the  pubic  portion  of  the 
fascia  lata;  in  the  interval  between  the  spinous 
processes  of  the  pubis  it  is  prolonged  down- 
ward upon  the  spermatic  processes,  and  is 
continued  upon  them  in  the  form  of  a  sheath 
into  the  scrotum,  where  it  invests  the  testicle  ;  it 
is  very  thin  and  transparent  upon  the  spermatic 
process.  The  existence  of  this  structure,  to 
which  attention  appears  to  have  been  first 
directed  by  Camper,  can  always  be  demon- 
strated however  fat  or  young  the  subject  may 
be,  though,  as  has  been  stated,  it  is  not  always 
equally  manifest ;  it  seems  distinct  from  the 
subcutaneous  cellular  structure,  which  frequently 
forms  a  uniform  and  thick  stratum  of  fat  be- 
tween it  and  the  skin.  Different  views  have 
been  taken  of  its  nature ;  by  Scarpa  it  is  re- 
garded as  a  prolongation  of  the  fascia  lata  of 
the  thigh,  while  others  and  the  majority  consider 
it  as  a  continuation  of  the  superficial  fascia,  so 
called,  of  the  same  part,  and  formed  by  the  deep 
stratum  of  the  abdominal  subcutaneous  cellular 


310 


ILIAC  ARTERIES. 


structure  converted  by  condensation  or  removal 
of  its  adeps  into  an  expansion  ;  to  me  it  appears 
that  the  view  taken  of  its  nature  by  Scarpa  is  cor- 
rect, not  in  the  sense  that  it  is  a  prolongation  of 
the  fascia  lata,  but  that  it  is  of  the  same  nature, 
and  that  it  is  to  the  abdomen  the  same  structure 
which  the  fascia  lata  is  to  the  thigh  ;  it  is  a 
question  entitled  to  consideration  only  for  ac- 
curacy's sake,  but  I  have  frequently  verified  the 
inferior  connections  of  this  expansion  such  as 
they  have  been  detailed,  and  further  it  appears 
to  me  that  it  is  not  properly  continuous  with 
the  superficial  fascia  of  the  thigh,  for  if  it  be 
detached  from  the  aponeurosis  of  the  oblique 
muscle  and  the  crural  arch  without  injury  to  its 
connection  with  the  fascia  lata,  and  be  then 
held  perpendicular  to  the  latter,  the  superficial 
fascia  of  the  thigh  may  be  removed  from  the 
angle  which  it  will  thus  form  with  the  fascia 
lata,  and  its  connection  still  remain  perfect : 
a  favourable  subject  and  a  careful  dissection 
will  certainly  be  required  for  the  purpose,  but 
this  circumstance  will  not  invalidate  the  con- 
clusion ;  it  is  also  to  be  recollected  in  making 
the  dissection,  that  the  fascia  detaches  processes 
over  the  inguinal  lymphatic  glands. 

The  structures  of  the  second  order  of  parts 
concerned  with  our  subject,  are  the  aponeurosis 
of  the  external  oblique  muscle,  the  internal 
oblique  and  the  transversalis  muscles;  of  these 
the  first,  which  is  immediately  beneath  the 
fascia,  extends  over  the  entire  anterior  wall  of 
the  fossa  reaching  from  the  linea  semilunaris 
above  to  the  crural  arch  below  ;  internally  it  is 
united  with  that  of  the  other  side  in  the  linea 
alba,  and  inferiority  it  forms  the  crural  arch  by 
its  border,  which  is  attached  externally  to  the 
superior  anterior  spinous  process  of  the  ilium, 
internally  to  the  spinous  process  of  the  pubis, 
and  in  the  interior  to  the  iliac  fascia  and  the 
fascia  lata.  The  direction  of  this  band  is  to  be 
borne  in  mind,  for  it  does  not  run  directly  from 
one  of  these  points  of  bone  to  the  other ;  but 
it  descends  toward  the  thigh,  and  recedes  from 
the  surface  at  the  same  time  that  it  passes  in» 
ward,  hence  it  is  concave  both  forward  toward 
the  surface  and  upward  toward  the  abdomen  ; 
the  cause  of  this  direction  is  its  connection 
inferiorly  and  posteriorly  with  the  fascia  lata 
and  the  fascia  iliaca.  The  aponeurosis  consists 
primarily  of  tendinous  fibres  which  run  in  the 
same  direction  as  the  fibres  of  the  muscle,  i.  e., 
downward  and  inward,  parallel  to  each  other, 
and  also  to  the  crural  arch,  though  rather  con- 
verging toward  it  internally,  and  thereby  form 
a  tendinous  expansion ;  the  longitudinal  fibres 
of  the  aponeurosis  are  crossed  by  others  which 
run  downward  and  outward  ;  these  are  very 
irregular  in  number  and  do  not  interlace  with 
the  former,  to  which  they  are  superficial ;  hence 
the  aponeurosis  does  not  possess  great  strength 
in  the  transverse  direction,  and  its  longitudinal 
fibres  are  liable  to  be  separated,  and  deficien- 
cies to  be  thereby  formed  in  the  aponeurosis, 
which  are  not  ^infrequently  to  be  observed. 
The  superficial  inguinal  ring  is  seated  in  the 
aponeurosis  ;  this  aperture,  for  the  particulars  of 
which  see  the  articles  Abdomen  and  Herma, 
is  of  variable  form  and  size ;  in  some  cases  it 


is  elliptical,  in  others  triangular ;  in  the  male 
it  is  larger  than  in  the  female ;  its  position  is 
oblique,  the  longer  diameter  inclining  from  the 
pubis  upward  and  outward  toward  the  superior 
anterior  spinous  process  of  the  ilium ;  its 
actual  length  is  extremely  variable,  in  some 
instances  not  amounting  to  half  an  inch,  in 
others  exceeding  an  inch.  . 

The  inferior  part  of  the  internal  oblique  and 
of  the  transversalis  muscles,  which  alone  is 
concerned  in  the  anatomy  of  this  part  of  the 
abdominal  wall,  may  be  distinguished  into  two 
parts,  viz,,  their  muscular  portion  and  their 
aponeurosis.  The  muscles  are  both,  but  more 
particularly  the  latter,  very  thin,  though  of 
great  width  ;  they  are  placed  the  one  within  the 
other,  and  the  internal  oblique,  which  is  super- 
ficial to  the  transversalis,  also  descends  a  good 
deal  lower,  so  that  its  inferior  margin  approaches 
very  close  to  the  crural  arch,  leaving  only  suf- 
ficient space  between  them  for  the  escape  of 
the  spermatic  process,  which  it  covers  beneath 
the  aponeurosis  of  the  external  oblique,  and 
which  in  some  instances  passes  between  its 
fibres,*  while  the  margin  of  the  transversalis  is 
at  some  distance  from  the  arch,  and  rarely 
covers  the  process,  at  least  to  any  extent,  the 
process  escaping  from  the  deep  ring,  for  the 
most  part  below  the  margin  of  the  muscle ; 
Cloquet  has  even  seen  the  margin  of  the  muscle 
so  far  as  two  fingers'  breadth  above  the  point  of 
escape  of  the  cord,  and  its  fibres  are  usually 
pale,  fine,  and  scattered.  The  muscular  fibres 
of  the  lower  part  of  the  two  muscles  are  at- 
tached to  the  anterior  extremity  of  the  crest  of 
the  ilium  and  to  its  spinous  process,  also  to  the 
superior  aspect  of  the  outer  part  of  the  crural 
arch,  the  oblique  to  nearly  the  outer  half  of 
the  arch,  the  transverse  to  the  outer  third  or 
fourth,  but  the  ultimate  attachment  of  the 
latter  is  to  the  surface  of  the  fascia  iliaca  above 
the  arch,  to  which  they  adhere  very  intimately 
as  they  pass  forward  from  the  fascia  ;  they  run 
inward  nearly  transversely,  but  convex  forward 
in  proportion  to  the  prominence  of  the  abdo- 
men, those  of  the  oblique  over  the  deep  ring, 
and  the  spermatic  process  within  the  inguinal 
canal,  those  of  the  transverse  above  the  ring, 
until  they  have  both  passed  that  point ;  they 
then  descend  along  the  inside  of  the  process, 
and  at  the  same  time  recede  from  the  surface  so 
that  they  become  posterior  to  it,  and  terminate 
as  they  descend  in  a  thin  irregular  aponeurotic 
expansion  common  to  the  fibres  of  both  mus- 
cles, and  thence  denominated  "  the  conjoined 
tendon  ;"  though  designated  by  an  especial 
name,  this  is  in  reality  only  the  inferior  part  of 
the  general  conjoined  tendon  of  the  two  mus- 
cles which  terminate  between  the  umbilicus 
and  the  pubis  in  a  common  expansion  ;  this  is 
placed  superficial  to  the  rectus  muscle,  and  is 
inserted  into  the  linea  alba,  the  anterior  margin 
of  the  crest  of  the  pubis  as  far  as  its  spinous 
process,  and  thence  outward  into  the  pectineal 
line  of  the  bone,  there  forming  the  "  conjoined 
tendon"  of  the  anatomy  of  hernia.  This  struc- 
ture is  situate  behind  the  spermatic  process, 

*  Cloquet. 


ILIAC  ARTERIES. 


841 


between  it  and  the  fascia  transversalis  ;  it  ap- 
proaches very  near  to  the  inner  margin  of  the 
deep  ring,  and  at  its  insertion  into  the  pectineal 
line  it  meets  and  is  identified  with  Gimbernat's 
ligament;  it  is  closely  adherent  to  the  surface  of 
the  fascia  transversalis,  and  hence  that  fascia 
presents  an  appearance  of  thickness  and  strength 
upon  the  inside  of  the  deep  ring,  which  it  does 
not  really  possess.  From  the  inferior  margin 
of  the  internal  oblique  and  from  the  superior 
side  of  the  crural  arch  the  cremaster  muscle 
descends  upon  the  anterior  and  external  part  of 
the  spermatic  process,  forming  one  of  the 
coverings  of  the  process  within  the  inguinal 
canal,  of  course  concealing  it  after  the  division 
of  the  aponeurosis  of  the  external  oblique,  and 
requiring  to  be  detached  from  the  arch  along 
with  the  lower  fibres  of  the  internal  oblique  in 
order  that  the  process  may  be  fairly  exposed. 

The  deep  structures  of  the  anterior  wall  of 
the  iliac  fossa  are  also  three,  viz.,  the  fascia 
transversalis,  the  fascia  propria,  and  the  peri- 
toneum. 

1.  The  fascia  transversalis  is  most  remark- 
able in  the  iliac  region,  but  it  is  not  con- 
fined to  it,  being  to  be  traced  upward  to 
the  surface  of  the  diaphragm,  and  backward 
round  the  interior  of  the  lateral  walls  of  the  abdo- 
men. In  the  iliac  region  this  fascia  is  interiorly 
first  identified  with  the  fascia  iliaca  from  a  short 
distance  behind  the  anterior  superior  spinous 
process  of  the  ilium  to  the  outer  side  of  the 
external  iliac  artery,  or  about  the  middle  of  the 
crural  arch  ;  the  line  of  its  connection  with  the 
fascia  iliaca  runs  downward,  forward,  and  in- 
ward, at  a  short  distance  within  the  crest  of 
the  ilium  and  the  crural  arch,  approaching  the 
latter,  however,  as  it  descends,  until  at  the 
outside  of  the  artery  it  touches  it;  it  is  sepa- 
rated along  this  line  into  two  lamina?  which 
enclose  the  circumflex  iliac  artery  between 
them ;  there  is,  therefore,  an  interval  between 
the  arch  and  the  line  of  connection  of  the  two 
fascia?  in  which  the  fascia  iliaca  intervenes,  and 
to  the  surface  of  this  part  of  the  fascia  it  is 
that  the  internal  oblique  and  transverse  muscles 
are  attached.  In  the  second  place  the  fascia 
transversalis  descends  into  the  thigh  beneath 
the  crural  arch,  between  it  and  the  iliac  vessels, 
and  forming  the  front  of  their  sheath;  and, 
thirdly,  it  is  attached  upon  the  inside  of  the 
vessels,  along  the  pectineal  line  of  the  pubis 
posterior  to  the  conjoined  tendon  of  the  internal 
oblique  and  transverse  muscles,  between  it  and 
the  peritoneum,  and  separated  by  it  from  the 
spermatic  process,  which  is  m  front  of  both. 

Internally  the  fascia  transversalis  is  con- 
nected to  the  edge  of  the  tendon  of  the  rectus. 

Midway  between  the  superior  anterior  spi- 
nous process  of  the  ilium  and  the  spinous  pro- 
cess of  the  pubes,  and  at  from  half  to  three- 
fourths  of  an  inch  above  the  crural  arch,  the 
spermatic  process  escapes  from  the  abdomen, 
descending  within  a  cylindrical  prolongation  of 
the  fascia  by  which  the  process  is  enclosed,  and 
which  thus  forms  a  sheath  for  the  process.  By 
detaching  this  prolongation  from  the  fascia 
around  the  process,  a  circular  aperture  is 
formed  in  the  fascia,  which  is  the  deep  in- 


guinal ring,  the  situation  of  which  has  been 
just  defined.  On  the  inside  of  this  opening- 
are  situate  the  epigastric  vessels,  the  artery, 
and  vein  or  veins,  the  artery  in  the  former  case 
being  next  the  ring,  in  the  latter  at  times  the 
outer  of  the  two  veins. 

2.  The  fascia  propria  is  a  cellular  stratum  in- 
terposed between  the  peritoneum  and  the  struc- 
tures of  the  abdominal  walls  which  it  lines  ;  it 
varies  in  thickness  and  condition  at  different 
parts  and  in  different  subjects  ;  at  times  it  con- 
tains adeps,  at  others  it  is  purely  cellular,  or 
forms  a  condensed  expansion ;  in  the  iliac 
region  it  is  thicker  upon  its  posterior  than  its 
anterior  wall ;  on  the  latter  it  increases  in 
thickness  as  it  descends  towards  the  crural 
arch,  being  so  thin  towards  the  umbilicus  that 
the  peritoneum  adheres  very  closely  to  the  ten- 
dinous expansion  of  the  muscles;  at  the  deep 
inguinal  ring  it  is  more  dense,  and  the  perito- 
neum, the  fascia  transversalis,  and  it,  are  more 
intimately  connected  than  at  either  side ;  ex- 
ternal to  the  ring,  between  it  and  the  spinous 
process  of  the  ilium,  it  is  so  free  that  the  pe- 
ritoneum may  be  separated  without  difficulty 
from  the  interior  of  the  fascia  transversalis, 
and  along  the  crural  arch  it  forms,  from  the 
external  iliac  artery  outward,  a  soft  mass, 
sometimes  thick,  occupying  the  interval  left 
between  the  peritoneum  and  the  fascia  trans- 
versalis, at  the  reflection  of  the  former  from 
the  iliac  fossa  to  the  anterior  wall :  upon  this 
wall  it  encloses  the  epigastric  vessels,  the  um- 
bilical ligament,  and  the  spermatic  vessels,  and 
not  only  does  it  extend  universally  over  the  in- 
terior of  the  abdominal  walls  but  it  is  prolonged 
through  their  several  apertures  upon  the  parts 
which  pass  through  them,  as  in  the  case  of  the 
spermatic  vessels. 

From  the  anterior  wall  of  this  region  it  passes 
to  the  posterior,  where  it  lines  the  iliac  fossa, 
and  connects  the  peritoneum  or  the  viscera  to 
the  iliac  fascia  ;  at  the  outer  part  of  the  fossa 
it  is  remarkably  free,  soft,  and  easily  lacerated, 
so  that  the  peritoneum  can  be  detached,  pro- 
bably with  greater  facility  at  this  than  at  any 
other  situation;  at  its  inner  part  it  is  even  more 
abundant,  thicker  the  nearer  to  the  crural  arch, 
forming  the  investment  by  which  the  iliac  ves- 
sels are  inclosed,  and  descending  thence  into 
the  pelvis. 

Lastly,  the  peritoneum  of  the  anterior  wall 
is  continuous  inferiorly  with  that  of  the  iliac 
fossa,  being  reflected  from  the  one  to  the  other 
at  the  distance  of  five  or  six  lines  above  the 
crural  arch — a  fact  deserving  of  much  attention, 
since  it  permits  the  external  iliac  artery  to  be 
secured  without  disturbing  the  membrane.  In 
its  reflection  from  one  wall  of  the  region  to 
the  other  it  leaves  immediately  above  the  crural 
arch,  between  itself,  the  fascia  transversalis, 
and  the  fascia  iliaca,  a  triangular  interval  of 
some  lines,  occupied  by  the  fascia  propria, 
and  at  times  at  least  by  one  or  more  lymphatic 
glands;  this  space  is  widest  at  the  iliac  artery 
and  diminishes  as  it  extends  outward;  this  fact 
also  deserves  attention,  inasmuch  as  it  points 
out  where  the  fascia  transversalis  may  be  di- 
vided, if  necessary,  in  the  operation  of  expo- 


842 


ILIAC  ARTERIES. 


sing  the  external  iliac  with  least  clanger  to  the 
peritoneum,  viz.  on  the  outside  of  the  deep 
inguinal  ring  and  close  as  possible  to  the  crural 
arch.  The  peritoneum  of  the  anterior  wall  of 
the  fossa  is  weaker  toward  the  middle  line 
than  externally;  it  presents  toward  the  abdo- 
men two  depressions  or  recesses  denominated 
by  Velpeau  "  fossettes  inguinales,"  internal 
and  external;  these  depressions  vary  very  much 
in  their  depth,  sometimes  hardly  perceptible, 
at  others  of  considerable  depth  and  capacity, 
more  especially  the  external,  which  is  much 
the  larger;  they  are  produced  by  the  projection 
of  the  umbilical  ligament  from  the  interior  of 
the  abdominal  wall,  and  the  reflection  of  the 
peritoneum  round  the  ligament,  by  means  of 
which  a  triangular  fold,  wide  in  proportion  to 
the  degree  to  which  the  ligament  projects,  is 
formed,  the  base  of  which  is  below,  the  apex 
above  toward  the  umbilicus,  and  in  the  free 
edge  of  which  the  ligament  is  contained  ;  this 
fold  separates  the  depressions,  one  being 
external  to  it,  the  other  internal,  between  it 
and  the  urachus  ;  the  external  one,  the  bottom 
of  which  tends  forward  and  inward,  corresponds 
to  some  point  of  the  posterior  wall  of  the  in- 
guinal canal,  but  its  precise  relation  to  it  is 
uncertain,  because  of  the  irregularity  of  the 
position  of  the  umbilical  ligament ;  at  times 
it  is  identical  with  another  slight  depression 
situate  on  the  outside  of  the  epigastric  vessels, 
which  marks  the  situation  of  the  deep  inguinal 
ring,  the  ligament  in  such  case  being  behind 
these  vessels ;  at  others  it  corresponds  to  the 
wall  of  the  canal,  to  the  superficial  inguinal  or 
the  deep  femoral  rings,  the  ligament  being  in 
these  latter  cases  internal  to  the  epigastric 
vessels. 

The  branches  of  the  external  iliac  artery  de- 
serving of  particular  attention  are  usually  two, 
the  anterior  or  circumflex  iliac  and  the  epigas- 
tric arteries;  throughout  the  superior  part  of  its 
course  the  artery  gives  only  minute  branches  to 
the  peritoneum,  the  cellular  tissue,  the  psoas 
muscles,  and  the  lymphatics ;  the  other  two, 
which  have  been  mentioned,  are  given  off  im- 
mediately before  the  artery  escapes  from  the 
abdomen.  They  arise  at  a  very  short  distance 
above  the  crural  arch,  sometimes  so  high  as 
three-fourths  of  an  inch  from  it,  at  others  at  it, 
and  sometimes  again  below  the  arch  from  the 
femoral ;  they  proceed  one  from  the  outer  and 
the  other  from  the  inner  side  of  the  vessel^ 
sometimes  opposite  to  each  other,  at  others  in- 
differently one  above  the  other :  occasionally 
they  are  given  off  from  a  trunk  common  to 
both;  they  are  nearly  of  equal  size,  but  for  the 
most  part  the  epigastric  is  larger  than  the  cir- 
cumflex. 

1.  The  anterior  or  circumflex  iliac  artery, 
( arteria  circumflexa  iliaca  or  ilii ;  Fr.  artere 
circorijiexe  iliaque.,  ou  iliaqvc  ou  anterieure,) 
arises  from  the  outer  side  of  the  external  iliac 
on  a  level  with  or  somewhat  lower  than  the 
epigastric;  it  runs  outward  and  upward  above 
and  paiallel  to  the  crural  arch  as  far  as 
the  superior  anterior  spinous  process  of  the 
ilium;  during  this  course  it  lies  upon  the  fascia 
iliaca  superficial  to  the  psoas  and  iliacus  mus- 


cles and  the  anterior  crural  nerve,  and  it  is 
inclosed  in  a  triangular  canal,  formed  behind 
by  the  fascia  iliaca,  below  and  above  by  la- 
minae of  the  fascia  transversalis,  which  divides 
at  its  union  with  the  former,  in  order  to  inclose 
the  artery.  When  the  anterior  abdominal  wall 
has  been  thrown  down,  and  the  peritoneum 
with  the  fascia  propria  removed  from  the  iliac 
fossa,  the  course  of  the  vessel  may  be  traced  by 
a  white  line,  which  marks  the  union  of  the  two 
fasciae,  extending  from  the  middle  of  the  crural 
arch  upward  and  outward  within  about  three- 
fourths  of  an  inch  of  the  spinous  process  of 
the  ilium;  by  the  division  of  the  fascia  trans- 
versalis along  this  line  the  artery  will  be  ex- 
posed. 

During  its  course  toward  the  spinous  process 
the  artery  gives  branches  to  the  psoas  and 
iliacus,  the  transversalis  and  oblique  muscles, 
and  to  the  inguinal  glands  ;  near  the  process  it 
gives  upward  a  considerable  branch,  which 
ascends  in  the  anterior  wall  of  the  abdomen 
between  the  internal  oblique  and  transversalis 
muscles,  in  front  of  the  spinous  process,  serving 
with  its  accompanying  veins  as  a  guide  in  dis- 
section by  which  to  distinguish  between  the 
two  muscles;  it  divides  into  branches,  which 
are  distributed  to  the  muscles,  as  also  to  the 
structures,  which  cover  and  line  them,  and 
communicate  with  branches  of  the  epigastric, 
lumbar,  and  intercostal  arteries. 

The  circumflex  artery  pursues  its  course  and 
runs  backward  around  and  within  the  crest  of 
the  ilium,  internal  to  the  transversalis  muscle  ; 
during  its  course  it  gives  branches  inward  to 
the  iliacus  muscle  which  anastomose  with  si- 
milar branches  from  the  iliolumbar,  and  up- 
ward to  the  lateral  abdominal  muscles,  which 
are  partly  distributed  to  them,  partly  turn  over 
the  crest  of  the  ilium  and  communicate  with 
the  gluteal  artery,  and  in  part  communicate 
with  the  lumbar  or  intercostal  arteries.  Finally, 
the  artery,  very  much  reduced  in  size,  anasto- 
moses freely  with  the  termination  of  the  ilio- 
lumbar, which  pursues  a  similar  course  in  a 
contrary  direction  around  the  interior  of  the 
crest  of  the  ilium. 

The  circumflex  artery  has  been  found  by 
Monro  to  present  an  irregularity  deserving  of 
notice ;  he  has  seen  a  branch  from  it,  nearly  as 
large  as  the  epigastric,  pass  under  the  crural 
arch,  about  two  inches  from  the  symphysis 
pubis,  and  there  divide  into  branches,  which 
were  distributed  upon  the  symphysis  and  the 
fat  and  skin  over  the  arch. 

2.  The  epigastric  artery,  (Fr.  artere  epigiis- 
trique,  A.  sus-pubienne )  arises  from  the  in- 
ternal and  rather  anterior  part  of  the  iliac 
artery,  near  to  the  crural  arch ;  the  distance 
of  its  origin  from  the  arch,  however,  is  liable 
to  variety  ;  for  the  most  part  it  occurs  about 
half  an  inch  above  it,  but  it  is  frequently 
nearer  to  it,  or  even  at  it,  and  occasionally  it 
is  below  it,  arising  from  the  femoral  artery ;  it  is 
given  off,  as  has  been  stated,  from  that  part 
of  the  iliac,  which  is  left  uncovered  by  peri- 
toneum, and  its  point  of  origin  is  posterior  to, 
sometimes  above,  sometimes  on  a  level  with, 
and  at  others  below  the  reflection  of  the  mem- 


ILIAC  ARTERIES. 


843 


brane  from  the  posterior  to  the  anterior  wall  of 
the  abdomen.  Its  course  is  tortuous  ;  it  passes 
forward  and  inward  ;  when  its  origin  is  low,  or 
very  near  to  the  arch,  at  once  upward;  but 
when  its  origin  is  high,  at  first  downward  in 
front  of  the  external  iliac  vein,  and  then 
changing  its  direction,  when  it  has  reached  the 
reflection  of  the  peritoneum,  it  ascends  inward 
toward  the  outer  margin  of  the  rectus  muscle, 
in  front  of  the  membrane,  between  it  and  the 
iascia  transversalis ;  it  reaches  the  margin  of 
the  muscle  from  one  and  a  half  to  two  inches 
above  the  pubis,  and  then  passing  behind  it 
enters  its  sheath,  and  continues  its  course  upon 
the  posterior  surface  of  the  muscle  toward  the 
umbilicus,  and  terminates  by  dividing  into 
branches,  which  anastomose  freely  with  de- 
scending branches  of  the  internal  mammary 
artery  ;  the  main  course  of  the  vessel  is  there- 
fore oblique  upward  and  inward  ;  and  it  may 
be  defined  by  a  line  drawn  from  the  junction  of 
the  middle  and  inner  third  of  the  crural  arch  to 
within  half  an  inch  upon  either  side  of  the 
umbilicus. 

The  artery,  when  its  origin  is  high,  is  situate, 
at  its  outset,  behind  the  peritoneum,  posterior 
to  the  deep  inguinal  ring ;  in  the  rest  of  its 
course  it  is  at  first  beneath  and  then  before  it, 
in  immediate  contact  with  it  from  the  crural 
arch  to  the  edge  of  the  rectus,  and  enclosed  in 
the  fascia  propria,  but  in  the  remainder  sepa- 
rated from  it  by  the  back  of  the  sheath  of  the 
muscle  ;  it  therefore  forms  in  this  case  a  curve 
in  which  the  reflection  of  the  peritoneum  is 
contained,  and  through  which  the  vas  deferens 
forms  a  similar  curve, — the  aspect  of  the  curves 
being  however  different,  the  convexity  in  the 
former  directed  downward,  and  in  the  latter 
outward  and  somewhat  upward — the  two  cords 
hooking  round  each  other;  in  its  ascent  from 
the  crural  arch  it  is  contained  in  the  posterior 
wall  of  the  inguinal  canal,  between  the  fascia 
transversalis  and  the  peritoneum,  crossing  the 
canal  nearly  at  right  angles,  and  intermediate 
to  the  two  rings,  being  distant  from  the  outer 
part  of  the  superficial  one,  according  to  the 
size  of  the  aperture,  from  half  an  inch  to  an 
inch  and  a  half,  and  in  its  relation  to  the  deep 
ring  varying  from  the  margin  of  the  aperture 
itself  to  four  or  five  lines  distance  from  it.  It 
is  accompanied  sometimes  by  one,  at  others  by 
two  veins ;  in  the  former  case  the  artery  is 
always  external  and  next  to  the  margin  of  the 
ring;  in  the  latter,  one  of  the  veins  is  at  times 
between  it  and  the  aperture. 

The  relation  of  the  artery  to  the  inguinal 
rings  indicates  at  once  that  which  it  must  hold 
to  the  neck  of  the  sac  in  the  two  original  forms 
of  inguinal  hernia  ;  in  the  oblique  or  external 
inguinal  hernia  it  is,  as  a  matter  of  course,  placed 
beneath  and  on  the  inside;  and  in  the  direct  or 
internal  inguinal,  upon  the  outside  of  the 
neck  ;  but  in  the  former  it  must,  in  consequence 
of  its  natural  vicinity  to  the  ring,  and  the  dila- 
tation of  the  latter,  be  close  to  and  surround 
the  neck  upon  the  two  sides  mentioned,  while 
in  the  second,  unless  the  aperture  be  much 
enlarged,  it  will  be  at  a  greater  or  less  distance 
from  it;  the  risk  of  danger  to  the  vessel  from 


cutting  to  the  side,  at  which  it  lies,  in  a  stran- 
gulation at  the  neck  of  the  sac,  must  therefore 
be  much  greater  in  the  former  than  in  the 
latter.  In  the  case  of  a  hernia  originally  ob- 
lique and  become  direct  by  long  continuance, 
the  artery  carried  inward  along  with  the  deep 
ring,  from  the  displacement  of  which  the 
hernia  assumes  the  character  of  the  direct  form, 
the  artery  is  of  course  situate  still  upon  the 
inside  of  the  neck,  which  at  the  same  time  it 
surrounds  to  a  greater  extent  than  in  the  former 
instances  ;  this  third,  though  secondary,  form  of 
inguinal  hernia  presents  another  case,  in  which 
the  relation  of  the  vessel  to  the  neck  of  the 
sac  demands  attention  the  more  that  the  true 
nature  of  the  case  being  obscure  and  the 
hernia  originally  and  secondarily  direct,  being 
thence  liable  to  be  confounded,  it  is  most  im- 
portant that  it  should  be  borne  in  mind  that 
the  artery  may  be  to  the  one  side  or  the  other, 
according  as  the  hernia  has  been  originally  or 
secondarily  direct.  The  epigastric  artery  is 
also  situate,  in  its  ascent,  external  to  the  deep 
femoral  ring  ;  its  distance  from  it,  in  the  natural 
state,  is  about  half  an  inch ;  but  when  hernia 
is  present,  and  the  neck  at  all  large,  the  epi- 
gastric vessels  are  close  to  its  outer  and  anterior 
side,  the  vein,  however,  being  between  the 
artery  and  the  ring;  when  the  obturator  artery 
arises  from  the  epigastric,  the  propinquity  of  the 
latter  to  the  ring  is  increased. 

The  branches  of  the  epigastric  artery  are 
numerous,  and  some  of  them  important.  Its 
first  branches  are  two  given  off  between  its 
origin,  and  the  deep  inguinal  ring,  higher  or 
lower,  according  to  the  situation  of  the  origin 
of  the  epigastric  itself ;  they  arise,  in  some  in- 
stances separately,  in  others  by  a  single  origin, 
and  they  run  over  to  the  posterior  surface  of 
the  pubis,  the  other  to  anastomose  with  the 
obturator  artery  ;  the  former,  the  pubic  branch, 
runs  inward  above  Gimbernat's  ligament, 
sometimes  along  its  anterior,  sometimes  along 
its  posterior  margin,  to  the  back  of  the 
pubis,  and  according  to  its  course  is  liable 
to  be  situate  before  or  behind  the  neck 
of  a  femoral  hernia.  The  second,  the  obtu- 
rator branch,  runs  backward,  downward  and 
inward  toward  the  superior  aperture  of  the  pelvis, 
i.e.  in  the  direction,  which  the  obturator  artery 
when  arising  from  the  epigastric  takes;  having 
descended  into  the  pelvis  it  joins  the  obturator 
at  a  variable  distance  between  the  origin  of 
that  vessel  from  the  internal  iliac  and  the  sub- 
pubic foramen;  frequently  it  divides  at  the 
brim  of  the  pelvis  into  two,  of  which  one 
joins  the  obturator  and  the  other  runs  backward 
along  the  brim  and  anastomoses  with  the  ilio- 
lumbar artery.  This  branch  holds  precisely  the 
same  relation  to  femoral  hernia  which  the 
obturator  when  arising  from  the  epigastric  does; 
it  is  very  variable  in  size,  and  it  is  upon  its  de- 
velopment as  compared  with  that  of  the  origin 
of  the  obturator  from  the  internal  iliac  that 
depends,  whether  the  former  shall  seem  a 
branch  of  the  latter,  or  of  the  epigastric  ;  when 
the  origin  of  the  obturator  from  the  iliac  has 
become  wanting,  this  branch  takes  its  place 
and  becomes  the  obturator. 


344 


ILIAC  ARTERIES. 


2.  The  epigastric  artery  in  passing  the  deep 
inguinal  ring  gives  a  branch,  which  goes  out 
through  the  ring  in  company  with  the  spermatic 
process,  descends  to  the  scrotum  and  is  distri- 
buted to  the  structures  of  the  cord,  to  the 
tunica  vaginalis,  and  to  the  cremaster,  and  anas- 
tomoses with  branches  of  the  spermatic  artery ; 
it  is  denominated  by  some  the  inferior  sper- 
matic artery. 

3.  As  the  artery  ascends  in  the  abdominal 
vvall  it  gives  to  either  side  numerous  branches, 
which  are  distributed  among  the  structures  of 
the  wall,  anastomosing  externally  with  branches 
of  the  circumflex  iliac,  of  the  lumbar  and  the 
inferior  intercostal  arteries,  and  internally  with 
those  of  the  artery  of  the  other  side ;  many  of 
these  branches  ultimately  become  superficial, 
passing  through  the  muscles,  and  through  aper- 
tures in  the  aponeurosis  of  the  external  oblique  ; 
they  terminate  in  the  superficial  structures, 
anastomosing  with  the  other  superficial  vessels. 
4.  Finally,  the  epigastric  artery  terminates  by 
two  or  more  long  ascending  branches,  which 
meet  and  anastomose  with  branches  from  the 
internal  mammary  artery. 

Methods  of  operation  for  the  ligature  of  the 
iliac  arteries. — The  methods  of  operation  for 
the  internal  and  primitive  lliacs  being  but  mo- 
difications of  those  adopted  for  the  external,  I 
propose  to  detail  the  latter  first. 

The  operation  in  each  case  may  be  resolved 
into  three  stages,  viz.  1,  the  division  of  the 
structures  of  the  abdominal  wall ;  2,  the  dis- 
placement of  the  peritoneum  with  the  inter- 
vening viscera;  3,  the  management  of  the 
artery  and  the  parts  immediately  related  to  it. 
Several  plans  have  been  proposed  for  exposing 
the  external  iliac  artery ;  these  may  be  regarded 
as,  all,  modifications  of  the  same ;  yet  their 
number,  the  existence  of  points  of  difference 
leddmg  to  results  of  some  importance,  and  the 
advantage  to  be  derived  from  a  clear  appre- 
hension of  them,  render  it  desirable  to  distin- 
guish them  so  far  as  they  present  distinctive 
characters  deserving  notice.  I  propose,  there- 
fore, to  particularize  five  methods,  between 
which  operators  may  have  occasion  to  select. 
In  the  first  the  line  of  incision  is  straight,  and 
corresponds  to  the  course  of  the  artery.  In  the 
second  the  line  of  incision  is  also  straight,  and 
inclines  away  from  the  course  of  the  artery 
toward  the  superior  anterior  spinous  process  of 
the  ilium.  In  the  third  the  line  of  incision  is 
curved,  convex  downward  toward  the  thigh,  and 
crosses  the  course  of  the  vessel.  In  the  fourth 
the  line  of  incision  is  straight,  and  transverse  to 
the  artery's  course.  The  fifth,  which  I  would 
specify,  is  a  modification  of  the  third,  by  which 
that  plan  may  be  rendered  more  generally  ap- 
plicable. The  first  is,  that  which  was  adopted 
by  Abernethy,  by  whom  the  artery  was  first 
tied,  A.D.  1796,  and  is  now  generally  known  as 
his  method,  of  which  the  following  is  his  own 
account : — "  I  first  made  an  incision,  about 
three  inches  in  length,  through  the  integuments 
of  the  abdomen,  in  the  direction  of  the  artery, 
and  thus  laid  bare  the  aponeurosis  of  the  ex- 
ternal oblique  muscle,  which  I  next  divided 
from  its  connection  with  Poupart's  ligament,  in 


the  direction  of  the  external  wound,  for  the 
extent  of  about  two  inches.  The  margins  of 
the  internal  oblique  and  transversalis  muscles 
being  thus  exposed,  I  introduced  my  linger 
beneath  them  for  the  protection  of  the  peri- 
toneum, and  then  divided  them.  Next,  with 
my  hand  I  pushed  the  peritoneum  and  its  con- 
tents upwards  and  inwards,  and  took  hold  of 
the  artery."* 

The  second  method  seems  due  to  several, 
and  first  also  to  Abernethy.  This  may  seem 
doubtful,  from  the  account  of  his  second  ope- 
ration originally  given  by  himself,  in  which  he 
says  merely  that  "  an  incision  of  three  inches 
in  length  was  made  through  the  integuments 
of  the  abdomen  beginning  a  little  above  Pou- 
part's ligament,  and  being  continued  upwards  ; 
it  has  more  than  half  an  inch  on  the  outside  of 
the  upper  part  of  the  abdominal  ring,  to  avoid 
the  epigastric  artery."f  But  in  his  collected 
worksj  of  different  dates  it  is  expressly  stated 
of  this  and  his  subsequent  operations  that  the 
incision  "began  just  above  the  middle  of 
Poupart's  ligament,  and  consequently  external 
to  the  epigastric  artery,  and  was  continued 
upwards,  but  slightly  inclined  towards  the 
ilium."  The  plan  adopted  by  Frere  differed 
not  much  from  this.  This  method  appears 
however  more  particularly  attributable  to  lloux, 
who  seems  to  have  been  the  first  to  give  specific 
instructions  for  it,  recommending  that  the  be- 
ginning of  the  incision  should  never  be  further 
than  half  an  inch  from  and  a  very  little  higher 
than  the  anterior  superior  spine  of  the  ilium, 
and  that  it  should  be  carried  very  obliquely 
downwards  to  the  middle  of  Poupart's  liga- 
ment^ 

The  third  method  is  that  of  Sir  A.  Cooper, 
in  which  the  incision  is  begun  just  above  the 
abdominal  ring,  and  is  extended  downward  in 
a  semilunar  direction  to  the  upper  edge  of 
Poupart's  ligament,  and  again  upwards  to 
within  an  inch  of  the  anterior  superior  spinous, 
process  of  the  ilium.  This  incision  exposes 
the  tendon  of  the  external  oblique  muscle  :  in 
the  same  direction  the  above  tendon  is  to  be 
cut  through,  and  the  lower  edges  of  the  in- 
ternal oblique  and  transversalis  muscles  ex- 
posed :  the  centre  of  these  muscles  is  then  to 
be  separated  from  Poupart's  ligament :  the 
opening  by  which  the  spermatic  cord  quits  the 
abdomen  is  thus  exposed,  and  the  finger  passed 
through  it  is  directly  applied  upon  the  iliac 
artery  above  the  origin  of  the  epigastric  and 
circumflex  ilii  arteries :  the  next  step  of  the 
operation  consists  in  gently  separating  the  vein 
from  the  artery  by  the  extremity  of  a  director 
or  the  end  of  the  finger ;  the  aneurismal 
needle  is  then  passed  under  the  artery. || 

The  fourth  is  that  of  Bogros,  in  which  the 
line  of  incision  is,  as  I  understand  it,  straight, 
from  two  to  three  inches  long,  immediately 
above  the  crural  arch,  and  has  its  extremities 

*  Surgical  Works,  1830,  v.  1,  p.  292. 
t  Surgical  Observations,  1804,  p.  214. 
t  Surgical  Works,  1830,  p.  396. 
§  Cooper's  Dictionary,  and  Nouveaux  Elemens  do. 
Med.  Op. 

||  Cooper's  Lectures  by  Tyrrell,  v.  11. 


ILIAC  ARTERIES. 


845 


equidistant,  the  external  from  the  spine  of  the 
ilium,  and  the  internal  from  the  symphysis  of 
the  pubis.  The  aponeurosis  of  the  external 
oblique  muscle  having  been  laid  open  in  the 
direction  of  the  crural  arch  upon  a  grooved 
director,  the  spermatic  cord  with  the  cremaster 
is  to  be  drawn  upward  beneath  the  superior  lip 
of  the  wound ;  the  deep  ring  dilated  with  the 
point  of  the  finger ;  the  epigastric  vessels,  if 
a  guide  be  necessary,  followed  toward  their 
origin ;  the  cellular  structure  and  lymphatic 
glands  situate  above  the  arch  upon  the  artery 
separated  ;  and  the  vessel  exposed  and 
isolated.* 

In  the  fifth  method,  which  is  but  a  modi- 
fication of  Cooper's,  the  outer  extremity  of 
the  incision  as  directed  by  him  is  prolonged 
to,  or  beyond  the  superior  spinous  process  of 
the  ilium  in  proportion  to  circumstances. 

Before  these  methods  be  contrasted  with 
each  other,  a  few  additional  remarks  seem  re- 
quired in  reference  to  the  operation  however 
performed. 

1.  The  posture  of  the  patient  should  be  such 
as  will  most  relax  the  abdominal  muscles  in 
order  to  prevent  as  much  as  possible  their 
pressure  upon  the  viscera,  and  to  allow  the 
more  easy  separation  of  the  edges  of  the  wound. 
The  shoulders  should  be  raised  and  the  legs 
bent  upon  the  pelvis. 

2.  It  seems  desirable  that  unless  the  super- 
ficial wound  be  longer  than  has  been  stated, 
the  division  of  the  aponeurosis  of  the  external 
oblique  should  be  of  equal  extent. 

3.  The  recommendation  to  divide  that  apo- 
neurosis upon  a  director  appears  judicious  as 
a  means  both  of  facility  and  safety. 

4.  Where  it  can  be  used  the  finger  seems  a 
safer  instrument  with  which  to  separate  the 
internal  oblique  and  transversalis  muscles  from 
the  structures  beneath,  for  it  will  be  readily 
understood  that  the  extremity  of  a  director 
might  be  easily  thrust  through  the  peritoneum 
in  the  execution  of  this  step. 

5.  It  must  be  borne  in  mind  that  between 
the  muscles  and  the  artery  there  are  to  be  ex- 
pected beside  the  peritoneum  two  other  struc- 
tures :  1.  the  fascia  transversalis;  2.  the  im- 
mediate investment  of  the  vessels.  The  fascia 
transversalis  may  either  be  treated  in  the  manner 
directed  by  Cooper,  viz.  by  dilating  the  deep 
ring,  or  be  lacerated  with  the  nail,  as  recom- 
mended by  Guthrie,  but  it  is  to  be  recollected 
that  a  prolongation  of  the  fascia  descends  upon 
the  spermatic  cord,  and  that  therefore  there 
exists  no  opening,  and  that  the  fascia  varies 
in  strength,  and  may  at  times  be  found  so 
strong  as  to  require  more  force  to  lacerate  it 
than  it  may  be  deemed  proper  to  exert.  In 
such  case  an  opening  may  be  made  through  it 
with  the  knife,  and  enlarged  upon  a  director 
if  necessary.  This  may  be  effected  by  either 
of  two  methods,  viz.  either  by  dividing  the 
prolongation  of  the  fascia,  which  descends 
upon  the  spermatic  process,  "  having  been  first 
raised  with  a  forceps,  to  a  sufficient  extent  to 
admit  the  forefinger  to  pass  upon  the  cord  into 

*  Archives  GenOraks  ck  Med.,  t.  iii.  p.  408. 


the  internal  abdominal  ring," — a  proceeding 
adopted  by  Mott,  and  which  offers  a  safe  mode 
of  opening  that  structure ;  or  by  cutting  the 
fascia  upon  the  outside  of  the  ring,  in  the  di- 
rection toward  the  superior  spine  of  the  ilium, 
to  such  an  extent  as  may  allow  the  introduction 
of  the  director  or  the  finger :  the  section  can- 
not  be  attempted  safely  inward,  because  of  the 
vicinity  of  the  epigastric  artery,  which  is  so 
near  to  the  inner  side  of  the  deep  ring  that  it 
must  in  such  case  be  exposed  to  imminent 
danger,  situate  as  it  is  between  the  fascia 
and  the  peritoneum ;  on  the  other  hand  the 
more  close  attachment  of  the  fascia  to  the  latter 
membrane  in  proportion  as  it  recedes  from  the 
crural  arch  forbids  the  section  of  the  fascia  di- 
rectly upward  ;  while  the  existence  of  the  tri- 
angular interval,  which  has  been  described, 
between  the  fascia  and  the  peritoneum  imme- 
diately above  the  arch  renders  the  membrane 
safe  from  injury  in  a  division  outward  near  to 
the  arch  :  it  must  however  be  recollected  that 
in  approaching  the  arch  the  circumflex  ilii 
artery  is  also  approached  and  endangered,  so 
that  the  incision  should  not  be  brought  too 
near  to  that  part,  but  made  in  the  direction 
mentioned,  nor  in  any  case  be  larger  than  will 
suffice  for  the  introduction  of  the  finger  or  the 
director. 

6.  The  immediate  investment  of  the  vessels 
frequently  opposes  great  resistance  to  the  sepa-- 
ration  of  the  artery  and  vein,  and  to  the  iso- 
lation of  the  former;  this  impediment  is  due 
not  merely  to  the  strength  of  the  investment, 
but  also  to  the  absence  of  a  resisting  support 
behind  the  vessel  as  it  recedes  from  the  pubis, 
in  consequence  of  which  it  yields  to  the  pres- 
sure exerted  to  separate  it.  In  such  case  the 
nail,  the  director,  or  the  knife  has  been  recom- 
mended for  the  division  of  the  expansion ; 
Abernethy  made  a  slight  incision  on  either  side 
of  the  artery.  The  nail  does  not  seem  the  best 
instrument  in  this  instance,  because,  by  the 
use  of  it  the  vessel  must  be  a  good  deal  dis- 
turbed, a  circumstance  to  be  avoided  when- 
ever it  can  be  ;  the  knife  again  must  be  attended 
with  risk  unless  used  with  great  caution  and 
in  steady  hands,  and  the  risk  is  the  greater 
when  the  incision  is  made  at  one  side  of  the 
artery,  since  the  vein  is  thereby  endangered  ; 
it  would  seem  a  safer  proceeding  and  one  less 
likely  to  disturb  the  artery  unnecessarily,  if, 
when  it  can  be  done,  the  investment  were 
pinched  up  with  a  forceps  over  the  middle  of 
the  artery  and  then  divided  to  the  extent  to 
which  it  may  have  been  raised,  after  which, 
with  the  director  or  the  blunt  aneurism- needle, 
the  artery  may  be  isolated  with  facility  while 
the  investment  is  drawn  to  either  side  with  the 
forceps. 

7.  It  is  to  be  borne  in  mind  that  one  or 
more  lymphatic  glands  usually  lie  in  front  of 
the  artery  imbedded  in  the  cellular  structure 
which  forms  its  investment,  and  that  these 
may  be  to  be  displaced. 

8.  In  operations  upon  the  iliac  arteries,  more 
particularly  when  performed  after  the  method 
of  Abernethy,  or  upon  the  internal  or  primi- 
tive vessels,  a  protrusion  or  bearing  down  of 


846 


ILIAC  ARTERIES. 


the  abdominal  viscera  is  to  be  expected  which 
has  been  found  a  great  obstruction  to  the 
operation :  this  will  be  most  effectually  pre- 
vented by  the  use  of  purgatives  previous  to  the 
operation ;  by  posture,  the  abdominal  muscles 
being  thereby  relaxed  as  much  as  possible ; 
and  during  the  operation,  if  it  occur,  by  the 
use  of  curved  spatulas  of  considerable  width 
and  curve,  as  used  by  Mott,  with  which  the 
viscera  may  be  supported. 

9.  In  the  passage  of  the  ligature  it  will 
always  be  necessary  to  be  assured  that  the 
genito-crural  nerve  is  not  included ;  but  it  may 
be  avoided  without  difficulty,  and  can  seldom 
require  to  be  divided.  lis  situation  should  be 
borne  in  mind,  viz.  above  external  to  the  artery, 
below  external  or  anterior. 

Lastly,  it  would  seem  the  safer  plan  to  pass 
the  needle  and  ligature  from  within  outward, 
inasmuch  as  the  vein  is  internal  to  the  artery. 
In  Cooper's  Lectures  edited  by  Tyrrell,  it  is 
directed  to  pass  the  needle  from  without ;  by 
so  doing  there  is  less  risk  that  the  genito-crural 
nerve  shall  be  included,  and  in  high  operations, 
since  the  vein  is  situate  so  much  beneath  the 
artery  at  the  superior  part  of  their  course,  it 
will  not  be  thereby  much  endangered,  but  at 
the  lower  part  the  vein  must  certainly  be  more 
exposed  by  that  mode  of  passing  the  ligature 
than  by  the  contrary  one,  while  the  nerve  may 
be  avoided  without  difficulty. 

We  shall  next  consider  the  comparative 
merits  of  the  several  plans  of  operation.  In 
the  method  of  Abernethy  the  direction  of  the 
line  of  incision  is  attended  with  the  following 
consequences.  1.  It  requires  a  more  extensive 
division  of  the  oblique  and  transversalis  mus- 
cles, and  hence  is  more  likely  to  be  followed 
by  weakness  of  the  abdominal  wall.  2.  Fal- 
ling, as  first  performed  by  him,  nearly  upon 
the  course  of  the  epigastric  artery,  it  exposes 
that  vessel  to  be  divided,  though  in  the  me- 
thod adopted  by  him  in  his  latter  operations 
this  risk  must  be  very  much  diminished,  if  not 
removed.  3.  The  extent  to  which  it  is  neces- 
sary to  divide  the  internal  oblique  and  trans- 
versalis muscles  must  expose  the  peritoneum 
lining  the  anterior  wall  of  the  abdomen  to  be 
lacerated  or  divided  during  their  separation. 
4.  The  parallelism  of  the  vessel  and  the  wound 
must  render  it  necessary  to  expose  a  greater 
length  of  the  former,  in  order  to  effect  its 
separation  from  the  contiguous  parts  and  to 
pass  a  ligature  round  it.  5.  It  is  therefore 
necessary  to  detach  the  peritoneum  in  all  cases, 
and  to  a  greater  extent  than  may  be  necessary 
or  required  by  a  different  method.  6.  The 
peritoneum  must  be  detached  to  an  equal  ex- 
tent from  both  walls  of  the  abdomen — from  the 
anterior  as  much  as,  or  it  may  be  more  than, 
from  the  posterior.  7.  The  protrusion  of  the 
viscera  must  be  more  likely  to  occur. 

It  is  asserted  by  some*  that  the  spermatic 
cord  is  more  exposed  to  injury  in  this  method  ; 
but  it  appears  to  me  that  it  cannot  be  more  so 
than  in  others,  and  that  it  ought  to  be  more 
safe. 

*  Velpeau. 


The  second  method  is  free  from  many  objec- 
tions to  which  others,  and  especially  the  first, 
are  exposed.  1.  It  does  not  endanger  any 
vessel  but  the  superficial  epigastric.  2.  It  does 
not  endanger  the  spermatic  cord.  3.  Probably 
it  does  not  tend  to  weaken  the  abdominal  wall 
as  much  as  the  first  method.  4.  It  renders 
necessary  a  much  less  extensive  detachment  of 
the  peritoneum,  since  the  line  of  incision  falls 
so  much  nearer  to  the  inferior  reflection  of  the 
membrane.  Add  to  these  that  by  it  the  artery 
may  be  reached  at  as  high  a  point  as  by  the 
first,  and  no  doubt  can  remain  that  it  is  to  be 
preferred  to  it ;  and  in  cases  requiring  a  high 
ligature  of  the  vessel  there  is  none,  save  the 
modification  of  Cooper's  method,  which  can 
be  considered  equally  eligible.  It  is  still, 
however,  subject  to  the  same  conditions  with 
the  first,  only  in  less  degree.  In  the  method  of 
Cooper,  on  the  contrary,  the  internal  oblique 
and  transversalis  muscles  are  divided  to  but  an 
inconsiderable  extent,  and  the  division  of  the 
aponeurosis  of  the  external  oblique  approaches 
more  to  the  course  of  its  fibres.  The  direc- 
tion of  the  incision  being  transverse  to  that  of 
the  artery,  the  vessel  may  be  exposed,  and  a 
ligature  passed  round  it  without  stripping  it  to 
a  great  extent  and  with  little  disturbance  of  it. 
Again,  for  the  same  reason  and  because  of  the 
vicinity  of  the  incision  to  the  crural  arch,  the 
vessel  may  be  exposed  either  without  dis- 
placing the  peritoneum  at  all,  or  displacing  it 
but  little  ;  and  when  it  is  necessary  to  displace 
the  membrane,  that  may  be  effected  with  the 
least  possible  disturbance  of  it,  inasmuch  as, 
because  of  the  propinquity  of  the  line  of  in- 
cision to  the  reflection  of  the  membrane,  it  is 
not  necessary  to  detach  the  latter  from  the 
anterior  wall  of  the  abdomen.  It  must  also 
be  less  exposed  to  the  protrusion  of  the  viscera, 
and  when  the  vessel  is  tied  below,  the  reflection 
of  the  peritoneum  must  be  exempt  from  it. 
This  method  permits  the  artery  to  be  reached 
at  from  an  inch  to  an  inch  and  a  half  above  the 
crural  arch. 

On  the  other  hand  this  method  endangers 
the  epigastric  artery  and  spermatic  cord  more 
than  the  others ;  the  former  because  the  line 
of  incision  crosses  the  vessel's  course,  com- 
mencing internal  to  it,  and  the  latter  because 
the  line  of  incision  crosses  and  sweeps  over 
the  cord  in  describing  its  curve.  Velpeau  con- 
siders that  there  is  greater  danger  to  these  parts 
in  the  method  of  Abernethy,  but  I  cannot 
concur  in  this  opinion,  for  the  lower  extremity 
of  the  incision  alone  can  fall  upon  the  situation 
of  the  cord,  and  in  the  mode  adopted  by  him 
in  the  majority  of  his  operations,  the  line  of 
incision  was  external  to  that  of  the  epigastric 
artery.  Experience  too  proves  that  there  is 
greater  danger  of  dividing  the  epigastric  artery 
in  the  method  of  Cooper,  since  the  accident 
has  occurred  more  than  once  in  it,  and  in  the 
most  dexterous  hands;  thus  Averill  relates  that 
the  artery  was  wounded  by  Dupuytren,  and 
Guthrie  also  states  that  he  has  seen  the  artery 
divided  in  the  performance  of  this  operation, 
while  I  am  not  aware  of  an  instance  in  which 
the  trunk  of  the  artery  has  been  divided  in  the 


ILIAC  ARTERIES. 


847 


method  of  Abernethy.    But  these  objections 
to  the  method  of  Cooper,  however  serious  in 
themselves,  seem  of  insufficient  weight  when 
contrasted  with  those  to  which  the  plan  of 
Abernethy  is  subject,  more  especially  since 
they  only  require  caution  to  be  effectually  ob- 
viated, while  the  others  are  inseparable  from 
the  plan  to  which  they  apply.    And  hence  the 
preference  has  been  given  to  his  method,  by 
the  greater  number  of  those*  who  have  had 
opportunities   of  experimentally  testing  the 
comparative  claims  of  the  two  in  all  cases 
where  it  is  applicable ;  i.e.  in  those  instances 
in  which  the  aneurismal  tumour  has  so  little 
encroached  upon  the  crural  arch,  or  in  which 
there  is  so  much  reason  to  consider  the  artery 
in  a  healthy  condition  immediately  above  the 
arch,  that  it  may  be  with  propriety  tied  near 
to  that  part.    Sabatier  is  of  opinion  that  the 
method  of  Abernethy  should  be  preferred  in 
every  case ;  but  the  number  of  authorities 
in  favour  of  the  other  is  so  great,  that  we  must 
consider  its  greater  eligibility  as  a  decided 
question.    And  the  method  of  Cooper  pos- 
sesses the  additional  and  great  recommendation 
that  it  may  at  any  time  be  so  modified  by  the 
prolongation  of  the  upper  extremity  of  the  in- 
cision, as  to  be  adapted  to  every  case,  so  that 
in  instances,  in  which  it  may  be  found  neces- 
sary to  tie  the  artery  at  a  greater  distance  from 
the  arch  than  the  original  plan  will  permit, 
this  modification  of  it  may  be  adopted  even  in 
the  course  of  the  operation :  for  the  most  part 
surgical  writers   recommend  a  preference  of 
Abernethy 's  first  plan  in  such  circumstances ; 
but  to  this  all  the  same  objections  which  have 
been  already  stated,  apply,  and  forbid  its  adop- 
tion, while  another  less  subject  to  them  and 
not   less  efficacious  presents    for  selection. 
Abernethy's  plan  certainly  promises  one  ad- 
vantage, viz.  that  the  line  of  incision  being 
nearer  to  that  of  the  artery  the  depth  of  it  from 
the  surface  is  likely  to  be  less,  unless  where 
the  abdomen  is  very  prominent,  than'  in  the 
latter,  in  which  the  obliquity  of  the  direction 
must  increase  the  depth  of  the  wound,  and  for 
the  same  reason  it  may  be  more  easy  to  obtain 
a  view  of  the  vessel,  and  to  direct  the  opera- 
tion by  the  sight,  which  must  be  more  difficult 
in  the  latter,  and  in  proportion  as  the  point  at 
which  the  operator  aims  is  higher ;  yet,  not- 
withstanding this  circumstance  in  favour  of  the 
method  of  Abernethy,  and  the  preference  given 
by  several  to  it  in  such  cases,  the  method  of 
Cooper,  modified  as  has  been  explained,  ap- 
pears to  me  still  preferable,  inasmuch  as  the 
greater  disturbance  of  the  peritoneum,  the  risk 
of  injuring  it  in  front,  and  the  greater  debility 
of  the  abdominal  wall  likely  to  be  the  con- 
sequence of  Abernethy's  method,  seem  to  out- 
weigh its  advantages ;  there  is  beside  another 
disadvantage  attending  the  latter  and  a  cor- 
responding advantage  attending  Cooper's  plan, 
which  must  be  experienced  when  an  aneuris- 
mal tumour  occupies  the  iliac  fossa,  viz.  that, 
by  the  former  the  peritoneum  must  be  detached 
from  all  the  front  of  the  tumour,  while  in  the 

*  Norman,  Todd,  Vclpcau. 


latter  the  lower  and  inner  part  of  it  may  be 
left  undisturbed,  and  this  I  consider  a  matter 
of  some  importance. 

The  method  of  Bogros  has  been  proposed  as 
an  improvement  upon  that  of  Cooper,  under  the 
impression  that  in  the  latter  the  incision,  which 
makes  nearly  a  right  angle  with  the  artery, 
corresponds  to  the  vessel  only  by  its  internal  ex- 
tremity, while  in  the  one  which  Bogros  proposes 
the  middle  of  the  incision  corresponds  directly 
to  the  artery ;  by  this  plan  he  further  maintains 
that  greater  facility  in  the  operation  is  ob- 
tained, and  the  artery  may  be  exposed  nearly 
an  inch  above  the  crural  arch  without  disturb- 
ing the  peritoneum,  while  in  Cooper's  the 
membrane  must  be  always  displaced,  and  the 
ligature  can  be  applied  at  only  a  very  short 
distance  from  the  arch.  Bogros  plainly  under- 
stands Cooper's  incision  to  commence  at  -the 
internal  abdominal  ring,  and  in  such  case  his 
objections  would  be  well  founded.  It  is  cer- 
tainly to  be  regretted  that  Cooper  has  used  an 
ambiguous  expression,  which  has  led  others 
beside  Bogros  to  mistake  his  meaning;  but  if 
reference  be  made  to  his  description  of  the 
anatomy  of  hernia  it  will  be  found  that  by  the 
"  abdominal"  he  intends  the  superficial  in- 
guinal ring,  and  if  so,  that  the  sole  difference 
between  his  and  Bogros'  plan  is  that  in  one  the 
line  of  incision  is  straight  while  in  the  other  it 
is  curved,  whence  the  comparative  results  must 
be  the  reverse  of  those  inferred  by  Bogros,  so 
far  as  the  facility  of  securing  the  artery  and  of 
reaching  it  at  a  greater  distance  from  the  crural 
arch  is  concerned.  If  however  it  be  desired  to 
secure  the  artery  immediately  above  the  crural 
arch,  between  it  and  the  reflection  of  the  peri- 
toneum, as  may  occur  in  cases  of  femoral 
aneurism,  the  method  of  Bogros  furnishes  a 
plan  fully  adequate  to  the  intention,  free  from 
the  necessity  of  disturbing  the  peritoneum  and 
easy  of  execution ;  at  the  same  time  that  it  is 
subject  to  the  objection,  that,  unless  care  be 
taken  to  prevent  it  by  tracing  the  vessels  to 
their  origin,  which  must  render  the  operation 
more  complicated  and  delicate,  the  artery  is 
more  likely  to  be  tied  below  the  origin  of  the 
epigastric  and  circumflex  arteries  by  this  than 
by  any  other  plan,  and  this  upon  two  accounts 
had  better  be  avoided,  so  that  all  things  con- 
sidered this  plan  appears  to  me  not  so  eligible 
as  that  of  Cooper,  in  which  it  is  altogether 
optional  with  the  operator  whether  he  shall 
disturb  the  peritoneum  or  not,  or  whether  he 
shall  tie  the  vessel  immediately  above  the  arch 
or  farther  from  it,  the  one  method  being  ap- 
plicable to  all  cases, and  not  requiring,  perhaps 
during  the  operation,  a  transition  to  another, 
after  that  the  first  has  been  found  insufficient. 

The  modification  of  Cooper's  plan,  which 
has  been  enumerated  as  a  fifth  method,  can  be 
required  only  in  those  cases,  in  which  it  may- 
be necessary  to  reach  a  very  high  point  of  the 
external  or  the  primitive  iliac.  In  such  it  will 
be  a  question  whether  to  adopt  Abernethy's 
original  method,  the  second  method,  or  the  one 
under  consideration  :  for  myself  it  appears  to 
me  that  the  first  ought  to  be  abandoned  in 
operations  upon  the  external  or  primitive  iliacs, 


848 


ILIAC  ARTERIES. 


unless  there  be  something  peculiar  in  the  par- 
ticular case  to  justify  its  adoption.  The  ad- 
vantages of  the  second  method  have  been 
partly  stated  ;  to  these  is  to  be  added  that  the 
line  of  incision  will  be  made  to  correspond  more 
to  that  of  the  artery  than  by  the  last  method, 
and  consequently  the  wound  will  be  less  oblique 
in  depth,  whence  probably  there  will  be  less 
difficulty  experienced  in  holding  aside  the  parts 
which  intervene  between  the  surface  and  the 
vessel ;  and  certainly  the  operator,  who  may 
be  apprehensive  of  injuring  the  epigastric  and 
circumflex  iliac  arteries  or  the  spermatic  process, 
will  do  well  to  adopt  it.  Still  for  some  reasons 
I  feel  disposed  to  prefer  the  last,  for  1,  it  re- 
quires less  disturbance  of  the  peritoneum  ;  2, 
it  appears  to  me  that  the  exposure  of  the  vessel 
must  be  greatly  facilitated  by  carrying  the  lower 
extremity  of  the  incision  across  the  course  of 
the  artery  to  its  inner  side,  which  is  not  accom- 
plished by  the  second  method  ;  3,  a  semilunar 
line  of  incision  furnishes  a  wound  of  greater 
length,  and  capable  of  being  more  widely 
opened  than  a  straight  one,  while  caution  will 
secure  the  spermatic  process  and  the  epigastric 
artery  from  injury ;  and  if  a  branch  of  the 
circumflex  iliibe,  as  it  is  likely  to  be,  divided, 
it  may  be  tied  with  ease.  This  was  the  me- 
thod adopted  by  Mott  in  the  operation,  in 
which  he  tied  the  primitive  iliac  artery';  a  case 
which  sufficiently  establishes  the  adequacy  of 
this  plan  for  the  high  ligature  of  the  vessel,  at 
the  same  time  that  it  displays  in  a  strong  light 
the  difficulties  for  which  the  operator  must  be 
prepared.  In  such  cases  the  method  of  di- 
viding the  internal  oblique  and  transversalis 
used  by  Mott  may  be  adopted  with  advantage, 
viz.  after  having  opened  the  fascia  transversalis 
to  insinuate  the  finger  between  it  and  the  peri- 
toneum, and  guided  by  it  to  divide  both  mus- 
cles at  once  from  within.  It  must  not  be 
forgotten  that  it  is  not  uncommon  to  find  the 
ureter  crossing  the  internal  iliac  artery,  upon 
the  right  side,  near  its  origin. 

Operations  for  the  ligature  of  the  internal 
iliac  artery.  —  The  method  adopted  in  this 
operation  by  Stevens,  by  whom  the  artery  was 
first  tied,  and  that  recommended  by  the  ma- 
jority of  writers,  is  similar  in  principle  to  the 
first  plan  of  Abernethy  for  the  external  iliac, 
and  differs  from  it  only  m  the  length  of  the 
incision,  which,  according  to  Guthrie,  should 
be  five  inches,  beginning  about  half  an  inch 
above  Poupart's  ligament  and  about  the  same 
distance  to  the  outside  of  the  inner  ring;  it 
should  be  nearly  parallel  to  the  course  of  the 
epigastric  artery,  but  a  little  more  to  the  out- 
side, in  order  to  avoid  it  and  the  spermatic 
cord,  and  have  a  gradual  inclination  inwards 
toward  the  'external  edge  of  the  rectus  muscle : 
according  to  Hodgson  the  centre  of  it  should 
be  nearly  opposite  the  superior  anterior  spinous 
process  of  the  ilium.  The  aponeurosis  of  the 
external  oblique,  and  the  internal  oblique  and 
tranversalis  muscles  having  been  divided  with 
the  same  precautions  to  avoid  the  peritoneum, 
as  in  the  other  case,  the  fascia  transversalis  is 
to  be  torn  through  at  the  lower  and  outer  part, 
so  that  the  fingers  may  be  passed  outward 


towards  the  ilium,  and  the  peritoneum  detached 
from  the  iliac  fossa,  and  turned  with  its  contents 
inward  by  a  gradual  and  sidelong  movement  of 
the  fore  and  second  finger  inwards  and  upwards, 
until  passing  over  the  psoas  muscle  the  ex- 
ternal iliac  artery  is  discovered  by  its  pulsation. 
This  is  then  to  be  traced  upward  and  inward 
toward  the  spine,  where  the  origin  of  it  and 
the  internal  iliac  from  the  common  iliac  trunk 
will  be  felt.  The  artery  is  to  be  traced  down- 
ward from  its  origin  and  separated  with  care 
from  its  connections,  and  more  especially  the 
vein.  The  sides  of  the  wound  should  now  be 
separated  and  kept  apart  with  curved  spatuku 
in  order  that  the  surgeon  may,  if  possible, 
see  the  artery,  and  have  sufficient  space  fin* 
passing  the  ligature.  Great  care  must  be  taken 
to  avoid  every  thing  but  the  artery ;  the  peri- 
toneum which  covers,  and  the  ureter,  which 
crosses  it,  must  be  particularly  kept  in  mind  ; 
the  latter  may  be  separated  with  ease,  and 
usually  accompanies  the  former  as  it  is  being 
detached  from  the  artery.  The  situation  of  the 
external  iliac  artery  and  vein,  which  have  been 
crossed  to  reach  it,  must  be  always  recollected, 
and,  if  possible,  they  should  be  kept  out  of 
the  way  and  guarded  by  the  finger  of  an 
assistant.*  This  method  has  in  this  case  a 
recommendation,  which  it  does  not  possess  for 
the  other  iliacs,  viz.  that,  as  it  is  necessary  in 
tying  the  internal  iliac  to  descend  more  or  less 
into  the  pelvis,  it  is  desirable  that  the  external 
wound  should  be  as  near  as  possible  to  the 
aperture  of  the  cavity,  but  the  danger  to  the 
peritoneum  must  be  even  greater  because  of 
the  greater  extent  to  which  it  must  be  separated, 
and  the  closer  attachment  of  it  to  the  ten- 
dinous than  the  muscular  structure  of  the 
abdominal  wall.  It,  therefore,  seems  to  me  a 
question  whether  even  in  this  case  the  line  of 
incision  here  recommended  should  be  adopted, 
and  whether  it  would  not  be  better  to  have 
recourse  to  that  either  of  Roux  or  Cooper. 
Gf  the  two  perhaps  the  former  may  be  best 
adapted  to  the  internal  iliac  for  the  reason  just 
assigned ;  though,  if  the  inferior  extremity  of 
the  incision  be  not  carried  beyond  the  middle 
of  Poupart's  ligament,  difficulty  must  be  ex- 
perienced in  exposing  the  vessel  and  passing 
the  ligature;  therefore  here  again  I  am  dis- 
posed to  prefer  the  semilunar  line  of  Cooper, 
only  not  brought  so  close  to  the  crural  arch  as 
for  the  external  iliac,  and  prolonged,  as  di- 
rected by  Velpeau,  two  inches  at  its  external 
extremity. 

It  is  recommended  to  pass  the  ligature  from 
within  outward  because  the  internal  iliac  vein 
is  posterior  to  the  artery ;  this  appears  to  me, 
however,  not  the  most  judicious  plan,  by  it  the 
point  of  the  needle  must  be  first  carried  out- 
ward and  then  forward  and  inward  in  order  to 
pass  round  the  vessel :  now  the  external  iliac 
vein  is  immediately  external  to  and  crossed  by 
the  artery;  the  junction  of  the  two  iliac  veins 
is  also  external  to  the  artery,  and  the  internal 
one,  though  posterior,  is  at  the  same  time  ra- 
ther external  to  it.    In  such  a  case  the  course 

*  Guthrie  on  Diseases  of  Arteries,  p.  371-2.  ' 


ILIAC  ARTERIES. 


849 


to  be  pursued  must  be  very  much  influenced 
by  the  convenience  of  the  moment;  but  it 
would  seem  the  better  plan,  where  a  choice  can 
be  made,  to  pass  the  needle  first  backward 
between  the  artery  and  the  external  iliac  vein, 
and  then  inward  behind  the  artery  toward  the 
pelvis,  by  which  plan  the  veins  will  be  more 
surely  avoided,  and  more  space  will  be  ob- 
tained for  seizing  the  ligature. 

In  this  as  well  as  every  operation  upon  the 
iliac  arteries,  the  spermatic  vessels  must  be 
kept  in  mind,  inasmuch  as  they  require  atten- 
tion as  much  as  the  ureter  ;  they  are  usually, 
however,  like  it,  removed  with  the  peritoneum. 
Velpeau  suggests  the  possibility  of  rupturing 
the  ilio-lumbar  artery  in  isolating  the  internal 
iliac,  and  the  risk  ought  not  to  be  overlooked. 

Ligature  of  the  primitive  iliac  artery. — Any 
of  the  methods  recommended,  whether  for  the 
internal  iliac  or  the  external  at  a  high  point, 
will  answer  for  the  ligature  of  the  primitive 
iliac.  Guthrie  gives  the  preference  to  that 
upon  Abernethy's  first  plan  in  this  as  in  the 
case  of  the  internal  iliac  ;  but  it  appears  to  me 
that  here,  at  all  events,  the  method  of  Roux  or 
the  modification  of  Cooper's  operation  is  to  be 
preferred  ;  for,  beside  that  there  does  not  exist  in 
this  case  the  reason  for  approximating  the  line  of 
incision  to  the  aperture  of  the  pelvis,  which 
applies  to  the  internal  iliac  artery,  the  situation 
of  the  aneurismal  tumour  in  front  must  render 
the  direct  line  of  incision  less  convenient  than 
a  lateral  one,  and  by  the  adoption  of  the  for- 
mer there  must  be  incurred  a  great  exposure 
of  the  peritoneum  without  a  commensurate 
advantage  ;  the  necessity  also  of  stripping  the 
membrane  from  all  or  a  great  part  of  the  front 
of  the  aneurism,  incurred  by  this  plan,  must 
be  very  objectionable.  The  length  of  incision 
recommended  by  Guthrie  is  five  inches  at  the 
least,  and  may  be  required  of  even  greater 
extent;  thus  Mott  was  obliged  to  extend  it  in 
his  case  upward  and  backward,  about  half  an 
inch  within  the  ilium,  to  eight  inches :  he 
adopted  the  principle  of  Cooper,  commencing 
his  first  incision  "  just  above  the  external  ab- 
dominal ring,  and  carrying  it  in  a  semicircular 
direction  half  an  inch  above  Poupart's  liga- 
ment until  it  terminated  a  little  beyond  the 
anterior  superior  spinous  process  of  the  ilium, 
making  it  in  extent  about  five  inches."  It  is 
likely  that  a  longer  incision  may  be  necessary 
in  this  method  when  applied  to  the  primitive 
iliac  than  in  that  recommended  by  Guthrie; 
the  greater  length  of  the  external  incision  is 
doubtless  an  objection  of  secondary  impor- 
tance; but  it  is  probable  that,  when  the  pri- 
mitive artery  is  to  be  tied,  little  will  be  gained 
by  commencing  the  incision  so  low  as  was 
done  by  Mott,  and  that  it  would  be  more  ad- 
vantageous to  carry  it  upward  rather  than 
downward ;  such  appears  to  have  been  the 
design  of  Crampton  in  the  operation  per- 
formed by  him  for  the  ligature  of  the  primitive 
iliac,  in  which  the  line  of  incision  was  curved, 
concave  toward  the  umbilicus,  and  extended 
from  the  anterior  extremity  of  the  last  rib  down- 
ward beyond  the  superior  anterior  spinous 
process  of  the  ilium,  and  since  unnecessary 

VOL.  II. 


division  of  the  abdominal  parietes  is  of  course 
to  be  avoided,  and  the  leaving  them  entire  at 
the  lower  part  must  be  attended  with  two  good 
results,  viz.  avoidance  of  the  aneurism  and  less 
subsequent  danger  of  pecuniary  protrusion, 
I  cannot  but  regard  this  plan  as  a  desirable 
addition  to  the  methods  of  proceeding  when 
the  primitive  iliac  is  the  vessel  to  be  tied. 
In  passing  the  ligature  the  difference  of  the 
relation  between  the  vein  and  artery  of  the 
opposite  sides  is  to  be  borne  in  mind,  the 
former  being  external  to  the  artery  on  the  right 
and  internal  on  the  left,  on  both  sides  however 
being  upon  a  posterior  plane. 

The  obstruction  to  the  course  of  the  opera- 
tion caused  by  the  protrusion  of  the  viscera  is 
to  be  expected  ;  in  that  of  Mott  it  is  described 
as  very  great,  while  no  mention  is  made  of  it 
in  Crampton's.  This  difference  was  probably 
the  consequence  of  the  difference  in  the  site 
of  the  wounds.  The  separation  of  the  artery 
and  vein  is  more  easily  effected  than  in  the  case 
of  the  external  ihacs,  because  their  investment 
is  less  thick  and  resisting. 

The  diversity  presented  by  the  arteries  of 
the  opposite  sides  suggests  a  difference  as  to 
greater  practicability  and  probability  of  success 
on  one  as  compared  with  the  other ;  the  artery 
of  the  right  side  being  longer  than  the  left 
presents  greater  room  for  the  application  of  a 
ligature  at  a  sufficient  distance,  whether  from 
the  seat  of  the  disease  or  from  the  origin  of  the 
vessel,  while  that  of  the  left  being  more  per- 
pendicular in  its  course  and  nearer  to  the  left 
side  of  the  body  ought  to  be  more  easily  ex- 
posed ;  but  it  is  to  be  recollected  that  this  dis- 
position is  not  uniformly  present. 

Before  undertaking  an  operation  upon  any 
of  the  iliac  arteries  it  will  be  advantageous  to 
determine,  so  far  as  possible,  the  relation  of 
the  vessel,  which  is  to  be  the  subject  of.it,  to  the 
superficial  points  of  the  abdominal  wall.  This 
must  be  understood  to  be  intended  only  as  an 
approximation,  but  by  attention  to  the  follow- 
ing circumstances  it  will  prove  sufficiently 
close  to  serve  the  desired  purpose.  The  mean 
point,  at  which  the  aorta  divides  and  the  pri- 
mitive iliac  commences,  is  half  an  inch  below 
the  umbilicus  at  its  left  side,  and  thit  at  which 
the  external  iliac  terminates  is  midway  between 
the  symphysis  pubis  and  the  superior  anterior 
spinous  process  of  the  ilium  :  of  course  a  line 
connecting  these  points  will  define  the  general 
course  of  the  primitive  and  external  iliac  arte- 
ries. The  length  of  the  primitive  iliac  being 
from  two  to  three  inches,  the  extent  of  its 
course  may  be  determined  by  the  subdivision 
of  this  line.  The  point  of  demarcation  be- 
tween the  primitive  and  external  iliacs,  and 
which  will  serve  to  mark  the  orfgin  of  the  in- 
ternal and  external,  as  well  as  the  termination 
of  the  primitive,  may  be  further  determined  by 
a  line  extending  from  the  crest  of  the  ilium 
about  one  inch  and  a  half  behind  its  anterior 
superior  spinous  process  to  a  similar  point  on 
the  other  side;  such  a  line  will  traverse  the 
sacro-vertebral  articulation  posterior  to  the  di- 
vision of  the  primitive  iliac,  and  by  its  decus- 
sation with  that  before  mentioned  will  mark 

3  K 


850 


ARTERIA  INNOMINATA. 


more  particularly  the  point  of  division  of  the 
vessel,*  which  will  also  correspond  nearly  to  the 
centre  of  a  line  drawn  from  the  anterior  superior 
spinous  process  of  the  ilium  to  the  umbilieus.f 

The  practicability  and  success  of  these  ope- 
rations have  been  so  long  established  that  they 
do  not  now  require  to  be  insisted  upon. 

When  the  external  iliac  has  been  tied  below 
the  origin  of  the  epigastric  and  circumflex  ilii 
branches,  the  circulation  of  the  limb  is  main- 
tained through  the  communications  of  the 
branches  of  the  internal  iliac  with  those  of  the 
femoral,  of  which  the  principal  have  been 
ascertained  by  Sir  A.  Cooper}  to  be  the  gluteal 
with  the  external  circumflex,  the  obturator  with 
the  internal  circumflex,  and  the  ischiatic  with  the 
profunda,  and  through  those  of  the  circumflex 
iliac  with  the  same.  (See  Femoral  Artery.) 
When  the  ligature  has  been  applied  above  the 
origin  of  these  branches,  the  circulation  is  esta- 
blished also  through  their  communications  with 
the  internal  iliac,  the  internal  mammary,  the 
inferior  intercostal  and  lumbar  arteries. 

The  ligature  of  the  internal  iliac  artery  can 
cause  little  interruption  of  the  supply  of  blood 
to  the  parts  to  which  it  is  distributed  ;  its  com- 
munications are  so  numerous  and  free,  exter- 
nally and  inferiorly  with  the  external  iliac  and 
femoral  arteries ;  inward  with  that  of  the  other 
side,  and  upward  with  the  aorta  through  the 
middle  sacral  and  hemorrhoidal  arteries,  that 
the  obstruction  of  the  main  trunk  can  affect  it 
but  little. 

When  the  primitive  iliac  has  been  tied  the 
circulation  must  be  restored  by  means  of  the 
communication  which  exists  between  the  arte- 
ries of  the  upper  and  lower  extremities  through 
the  internal  mammary  and  epigastric  arteries, 
of  that  between  the  aorta  and  the  iliac  arteries, 
through  the  intercostal,  lumbar,  middle  sacral, 
hemorrhoidal,  and  the  branches  of  the  latter,  and 
of  that  between  the  iliac  arteries  of  both  sides. 

For  Bibliography,  see  Anatomy  and  Artery. 

(B.  Alcock.) 

ARTERIA  INNOMINATA,  (in  human 

anatomy)  Fr.  Tronc  brach'w-cephalique. 

The  innominata  or  brachiocephalic  artery  is 
situated  to  the  anterior  and  right  side  of  the 
thorax,  extending  from  the  arch  of  the  aorta  to 
the  sterno-clavicular  articulation. 

Of  the  three  large  vessels  proceeding  from 
the  arch  of  the  aorta,  the  innominata  is  the 
most  anterior,  the  shortest,  but  of  the  largest 
calibre ;  it  takes  its  origin  at  a  point  corres- 
ponding and  very  nearly  parallel  to,  the  upper 
edge  of  the  cartilage  of  the  second  rib  almost 
immediately  from  that  part  of  the  arch  of  the 
aorta  where  it  alters  its  direction  from  the  right 
towards  the  left  side,  or  rather  from  the  com- 
mencement of  what  is  termed  the  transverse 
portion  of  the  arch,  and  hence  the  cause  of  its 
being  at  this  point  not  only  to  the  right  side 
but  also  anterior  and  rather  superior  to  the 
other  two,  which  arise  from  the  remainder  of 

*  Guthrie, 
t  Harrison. 

J  iVledico-Cliirurgical  Transactions,  vol.  iv. 


the  transverse  division  of  the  arch,  the  left 
carotid  and  subclavian  arteries.  It  imme- 
diately ascends  obliquely  upwards,  outwards, 
and  very  slightly  backwards,  to  opposite  the. 
right  sterno-clavicular  articulation,  where  it 
divides  into  the  right  sub-clavian  and  carotid 
arteries,  the  latter  of  which,  although  the  smal- 
lest in  diameter,  appears  from  direction  to  be 
its  continuation.  The  innominata,  therefore, 
is  but  a  short  trunk,  rarely  exceeding  from  an 
inch  and  a  half  to  two  inches  in  length.  Ne- 
vertheless instances  are  upon  record  in  which 
it  has  attained  above  two  inches  and  a  half ; 
but  these  may  be  considered  more  in  the  light 
of  anomalies  than  regular  occurrences. 

We  now  proceed  to  consider  the  various  re- 
lations which  this  vessel  bears  to  the  several 
important  organs  in  its  neighbourhood,  and  we 
shall  then  the  more  readily  be  able  to  account 
for  the  many  distressing  symptoms  usually 
accompanying  its  enlargement.  At  its  origin, 
it  lies  upon  the  trachea  and  at  its  division  cor- 
responds, although  at  a  considerable  distance, 
to  the  longus  colli  muscle  separated  from  it  by 
glands  and  cellular  tissue.  Internally,  or  on 
its  left  side  from  below  upwards,  are  the  com- 
mencement of  the  left  carotid  artery  and  the 
trachea,  the  latter,  however,  lying  upon  a  plane 
posterior  to  the  artery,  a  quantity  of  cellular 
tissue  and  glands  being  usually  met  with 
between  them.  Externally  or  to  its  right 
the  relations  are  more  complicated  and  consist 
of  parts  of  very  great  importance.  It  is  here 
connected  to  the  right  pleura  and  the  middle 
and  inferior  cardiac  branches  of  the  great  sym- 
pathetic nerve;  the  internal  jugular  vein  lies 
above  it  and  on  its  right  side,  whilst  the  right 
brachio-cephalic  vein  is  to  its  right  but  some- 
what anterior.  Behind  this  vein  and  crossing 
the  subclavian  artery  at  right  angles  very  close 
to  its  origin,  we  find  the  pneumo-gastric  nerve 
entering  the  thorax  and  giving  back  its  recur- 
rent branch  which  winds  round  the  subclavian 
artery;  still  more  externally  is  the  phrenic 
nerve  conducted  into  the  thorax  upon  the  an- 
terior border  of  the  anterior  scajpnus  muscle, 
and  between  the  two  latter  the  internal  mam- 
mary branch  of  the  subclavian  artery.  The 
parts  covering  the  vessel  are  studied  with 
greatest  advantage  from  the  integuments  back- 
wards ;  and  the  best  method  of  effecting  this  is 
as  follows,  as  it  enables  us  at  the  same  time  to 
take  a  clear  view  of  the  attachment  of  the 
various  layers  of  the  cervical  fascia  to  the  first 
bone  of  the  sternum  and  the  inter-clavicular 
ligament. 

Having  placed  the  subject  with  a  block 
underneath  the  shoulders,  and  the  head  hanging 
down,  thus  drawing  the  vessel  as  much  as 
possible  out  of  the  thorax,  carry  an  incision 
of  about  five  inches  upwards,  commencing  at 
the  middle  of  the  sternum  opposite  the  carti- 
lage of  the  second  rib.  Through  this  incision 
carry  another  of  the  same  length  at  right  angles, 
commencing  at  the  left  sterno-clavicular  arti- 
culation, and  extending  along  the  right  clavicle 
as  far  as  its  centre.  This  crucial  incision 
should  merely  divide  the  skin,  the  triangular 
flaps  of  which  are  next  to  be  raised  and  re- 


ARTERIA  INNOMINATA. 


851 


fleeted  to  the  right  and  left,  thus  exposing  a 
layer  of  fascia  separating  the  skin  from  vthe 
platisma  muscle  ;  this  fascia  is  thin  externally, 
but  where  it  corresponds  to  the  interval  between 
the  two  sterno-mastoid  muscles  it  becomes 
dense  and  more  or  less  loaded  with  fat ;  reflect 
this  fascia  and  the  platisma  will  next  appear, 
behind  which  is  that  usually  described  as  the 
superficial  fascia  of  the  neck  covering  the 
sterno-mastoid  muscle,  containing  the  external 
jugular  vein,  and  increasing  considerably  in 
density  above  the  sternum,  over  which  it  passes 
down  in  front  of  the  pectoral  muscles.  Like 
the  previous  layer  its  thickness  is  augmented 
by  fat.  If  this  be  raised  the  sterno-mastoid 
muscles  and  the  first  layer  of  the  deep  cervical 
fascia,  extending  between  their  two  anterior 
margins,  are  brought  into  view,  together  with 
some  small  superficial  vessels  and  nerves. 
This  latter  fascia  should  be  carefully  examined 
above  the  sternum  to  the  anterior  margin  of 
which  it  strongly  adheres  ;  it  is  very  dense,  so 
much  so  that  if  we  endeavour  to  force  a  finger 
into  the  thorax  at  this  point,  it  effectually  resists 
our  efforts.  Behind  this  fascia  is  a  space  cor- 
responding in  depth  to  the  thickness  of  the 
upper  edge  of  the  first  bone  of  the  sternum, 
containing  fat  and  usually  a  gland,  and  in  ad- 
dition a  vein  rather  larger  than  a  crow-quill, 
extending  across  the  neck  about  half  an  inch 
above  the  sternum;  this  communicates  with  a 
vein  on  either  side  of  the  neck  running  down 
on  the  anterior  margin  of  the  sterno-mastoid 
muscle,  and  should  be  carefully  avoided  by 
the  surgeon  in  the  operation  for  tying  the  in- 
nominata,  as  it  is  of  sufficient  size  to  cause 
embarrassment  if  wounded.  If  the  fat  and 
gland  be  now  removed  we  come  down  upon 
the  second  layer  of  this  fascia,  which  is  also 
very  dense  and  adheres  to  the  inter-clavicular 
ligament.  Having  examined  these  parts  and 
the  triangular  space  existing  between  the  sternal 
and  clavicular  insertions  of  the  sterno-mastoid 
muscles,  the  sternal  insertions  of  the  latter 
should  be  detached  and  the  first  bone  of  the 
sternum  removed  ;  this  will  expose  the  remains 
of  the  thymus  gland  and  the  sterno-hyoid  and 
thyroid  muscles,  which  being  cut  through  and 
reflected  upwards  are  found  to  cover  the  deep 
or  third  layer  of  the  cervical  fascia,  which 
may  be  traced  from  the  anterior  scalenus 
muscle  to  its  union  with  its  fellow  of  the  op- 
posite side,  binding  down  the  cervical  vessels, 
&c.  Upon  removing  this  fascia  we  come  down 
upon  the  arteria  innominate  covered  by  the 
following  parts ;  inferiorly  the  left  brachio- 
cephalic vein  passes  nearly  horizontally  across 
the  root  of  the  artery  to  form  the  vena  cava 
superior  by  uniting  with  the  corresponding 
vein  of  the  right  side.  Although  the  com- 
mencement of  the  vena  cava,  strictly  speaking, 
has  a  closer  relation  to  the  arch  of  the  aorta  than 
the  innominata,  it  is  nevertheless  sufficiently 
near  the  latter  to  render  it  of  considerable  im- 
portance in  operations  performed  upon  (hat 
vessel.  Superiorly  the  first  or  upper  cardiac 
nerve  in  its  course  towards  the  thorax  crosses 
the  innominata  opposite  its  bifurcation ;  we 
next  observe  the  right  inferior  thyroid  vein, 


which,  emanating  from  the  lower  portion  of 
the  thyroid  gland,  and  having  formed  with  its 
fellow  of  the  opposite  side  the  thyroid  venous 
plexus  runs,  obliquely  downwards  from  the 
gland  towards  the  right  side  directly  in  front 
of  the  innominata  artery,  and  empties  itself 
into  the  vena  cava  superior  between  the  two 
brachio-cephalic  veins.  The  middle  thyroid 
artery,  when  it  exists,  may  now  be  seen  ascend- 
ing in  front  of  the  trachea.  These  several 
objects,  viz.  the  left  brachio-cephalic  and  thy- 
roid veins  with  the  cardiac  nerve,  are  all  en- 
veloped in  a  quantity  of  loose  cellular  tissue 
and  glands  serving  to  connect  them  to  the 
vessel,  which  may  now  be  fully  exposed  and 
its  different  relations  studied ;  when  we  shall 
observe  that  on  its  right  side  there  is  a  space 
bounded  superiorly  by  the  right  subclavian 
artery,  inferiorly  by  the  left  brachio-cephalic 
vein,  to  the  right  by  the  right  brachio-cephalic 
vein,  and  to  the  left  by  the  innominata  artery 
itself ;  this  is  the  situation  where  the  aneurismal 
needle  should  be  introduced  in  the  operation 
for  tying  this  vessel,  as  we  thus  run  less  risk  of 
wounding  the  veins. 

From  the  above  description  it  is  evident  that 
the  coverings  of  the  innominata  may  be  ar- 
ranged into  ten  layers,  which,  enumerated  from 
the  surface,  consist  of 

1.  The  skin.  2.  Layer  of  superficial  fascia. 
3.  Platisma  myoides  muscle.  4.  Superficial 
fascia.  5.  First  bone  of  the  sternum,  sternal  ex- 
tremity of  the  right  clavicle,  sterno-mastoid 
muscle,  with  its  accompanying  vein  the  sterno 
and  inter-clavicular  ligaments  and  anterior  layer 
of  deep  cervical  fascia.  6.  Cellular  tissue,  fat, 
containing  large  vein  and  a  gland;  the  second 
layer  of  deep  cervical  fascia.  7.  Sterno-hyoid 
muscle.  8.  Sterno-thyroid  muscle.  9.  Third 
layer  of  deep  cervical  fascia.  10.  Cellular 
tissue  containing  the  first  cardiac  nerve,  right 
inferior  thyroid,  and  left  brachio-cephalic  veins, 
glands,  &c. 

Arrived  opposite  to  the  right  sterno-clavicu- 
lar  articulation  and  to  the  interval  between  the 
sternal  and  clavicular  insertions  of  the  sterno- 
mastoid  muscle,  the  arteria  innominata  usually 
divides  into  the  right  carotid  and  subclavian 
arteries.  It  rarely  gives  off  any  branches  ante- 
cedent to  its  division,  but  a  small  third  branch 
is  frequently  observed  proceeding  from  it  to 
distribute  itself  in  front  of  the  trachea,  and  ter- 
minate in  the  thyroid  gland.  Mr.  Harrison, 
in  his  work  on  the  Surgical  Anatomy  of  the 
Arteries,  has  named  it  the  "  middle  thyroid 
artery."  The  French  anatomists  give  M. 
Neubauer  the  credit  of  discovering  it,  and 
consequently  term  it  "  l'artere  thyroidienne  de 
Neubauer  "  It  is,  however,  as  frequently  given 
off  from  the  aorta  between  the  arteria  inno- 
minata and  left  carotid. 

When  we  consider  the  relation  which  the  in- 
nominata bears  to  the  important  organs  sur- 
rounding it,  we  can  scarcely  be  at  any  loss  to 
account  for  the  apparently  remote  symptoms 
present  in  aneurism  of  this  vessel ;  such,  for 
instance,  as  oedema  and  blueness  of  the  upper 
extremities,  head  and  neck,  cough,  difficulty 
of  breathing  and  swallowing,  vertigo,  failure 

3  k  2 


852 


ARTERIA  INNOMINATA. 


of  sight,  &c.  Where  the  tumor  extends  to- 
wards the  right  side  it  presses  upon  the  right 
brachio-cephalic  vein,  preventing  the  return  of 
blood  from  the  right  arm  and  side  of  the  head 
and  neck ;  if  upwards  in  that  direction  the 
carotid  and  subclavian  arteries  become  im- 
plicated, and  consequent  interruption  to  the 
circulation  ensues ;.  if  forwards,  the  passage 
of  blood  is  stopped  through  the  left  brachio- 
cephalic vein  and  the  inferior  thyroid  venous 
plexus ;  if  to-  the  left,  'it  encroaches  upon  the 
left  carotid  artery  and  trachea,  whilst  by  en- 
larging backwards  it  acts  immediately  upon  the 
trachea  and  mediately  upon  the  oesophagus. 

Although  the  above  facts  are  interesting,  as 
serving  to  elucidate  the  various  phenomena 
occurring  in  this  malady,  I  fear  that  we  must 
not  attach  too  much  importance  to  them  as 
means  of  diagnosis,  inasmuch  as  many,  if  not 
all,  of  the  above  symptoms  may  result  from 
enlargement  of  other  vessels  and  other  causes, 
indeed  we  have  only  to  turn  to  the  admirable 
work  of  Mr.  Allan  Burns  on  the  Surgical  Ana- 
tomy of  the  Head  and  Neck,  to  be  at  once  aware 
of  the  probability  of  deception  in  this  respect. 

Anom'alies. — There  are  perhaps  few  arteries 
in  the  body  which  present  so  many  varieties 
and  anomalies  as  the  innominata,  whether  stu- 
died with  respect  to  its  extent,  course,  situ- 
ation, or  the  number  of  brandies  which  it  gives 
off.  In  the  first  place,  it  is  frequently  met 
with  extending  up  into  the  neck  as  high  as 
the  thyroid  cartilage  before  it  divides  into  its 
ultimate  branches,  and  sometimes  lying  in 
front  of  the  trachea.  It  is  scarcely  necessary 
to  remark  in  how  great  a  degree  this  anomaly 
increases  the  difficulties  and  dangers  attending 
the  operation  of  tracheotomy.  Secondly,  the 
most  remarkable  variety  occurring  in  the  course 
of  this  artery  is  described  by  M.  Velpeau,  who, 
in  his  El^mens  de  Mcdecine  Operatoire,  men- 
tions three  instances  in  which  it  passed  to  the 
left  side  in  front  of  the  trachea,  and  subse- 
quently wound  from  before  backwards  over 
this  organ,  returning  between  the  oesophagus 
and  vertebral  column,  to  its  usual  points  of 
division  opposite  the  right  sterno-clavicular 
articulation.  Thirdly,  the  innominata  is  also 
occasionally  irregular  as  to  situation.  It  has 
been  found  arising  from  the  centre  of  the  trans- 
verse portion  of  the  arch  of  the  aorta  instead 
of  its  commencement,  and  dividing  into  right 
and  left  carotid  arteries,  the  right  subclavian 
taking  its  origin  from  the  spot  usually  occupied 
by  the  innominata.  Again,  instead  of  being 
placed  on  the  right  it  has  been  met  with  given 
off  from  the  left  or  posterior  part  of  the  arch 
dividing  into  the  right  and  left  carotids  and  left 
subclavian,  in  other  instances  into  left  sub- 
clavian and  left  carotid.  Cases  are  also  on 
record  in  which  the  innominata  was  altogether 
absent,  the  right  carotid  and  subclavian  arte- 
ries arising  directly  from  the  arch  of  the  aorta. 
Fourthly,  it  is  frequently  anomalous  in  the 
number  of  branches  it  gives  off.  Occasionally 
the  left  carotid  arises  from  it  in  addition  to  its 
usual  branches,  sometimes  it  divides  into  the 
two  carotids  instead  of  the  subclavian  and 
carotid;  and  Tiedemann  mentions  an  instance 


where  it  gave  off  the  right  internal  mam- 
mary. 

The  considerations  of  the  functions,  size,  and 
situation  of  the  innominata,as  well  as  its  relations 
not  only  to  the  heart  and  aorta  but  also  to  the 
surrounding  parts, at  all  times  rendered  the  study 
of  this  vessel  a  subject  of  interest  and  impor- 
tance in  the  eyes  of  the  operative  surgeon;  but 
it  is  comparatively  of  later  years  since  Mr. 
Allan  Burns  first  directed  the  attention  of  the 
profession  to  the  fact  that  circulation  through 
this  vessel  might  be  suddenly  arrested  without 
the  functions  of  the  brain,  and  power  of  the 
superior  extremity  being  of  necessity  de- 
stroyed, that  surgeons  have  been  found  bold 
enough  to  attempt  placing  a  ligature  upon  it. 

There  are  three  cases  upon  record  in  which  a 
ligature  has  been  placed  upon  the  trunk  of  the 
innominata  itself.  The  first  operation  was  per- 
formed by  Professor  Mott,  of  New  York,  on 
the  11th  of  May,  1818.  The  patient  died  on 
the  26th  day  after  the  operation  from  repeated 
hemorrhage  resulting  from  ulceration  and  yield- 
ing of  the  vessel. 

The  second  was  by  Professor  Graeff  on  the 
5th  of  March,  1829.  The  patient  died  on  the 
sixty-seventh  day  after  the  operation  from  re- 
peated hemorrhage. 

The  third  was  by  Mr.  Lizars  at  the  Edin- 
burgh Royal  Infirmary,  on  the  31st  of  May, 
1837.  The  patient  died  on  the  twenty-first  day 
after  the  operation,  likewise  from  hemorrhage. 

This  artery  was  likewise  tied  by  Mr.  Bland  on 
the  25th  March,  1832.  The  patient  died  on  the 
13th  of  April,  three  weeks  after  the  operation. 

The  following  are  the  steps  of  the  operation. 
The  patient  being  placed  in  the  horizontal  po- 
sition with  the  shoulders  raised  and  the  head 
thrown  back,  make  an  incision  of  about  two 
inches  upwards  along  the  anterior  margin  of 
the  sterno-cleido-mastoid  muscle  of  the  right 
side,  commencing  at  the  upper  edge  of  the 
sternum  :  from  the  inferior  extremity  of  this 
carry  another  of  similar  extent  outwards  upon 
the  right  clavicle;  these  should  divide  the  skin 
and  subcutaneous  tissue :  next  dissect  this  flap 
from  below  upwards  and  reflect  it,  exposing  the 
platisma  muscle  ;  cut  through  this  muscle  and 
the  superficial  fascia  beneath  it,  and  then  care- 
fully detach  the  sternal  insertion  of  the  sterno- 
mastoid  muscle  and  anterior  layer  of  deep 
fascia,  and  should  there  not  be  sufficient  space 
a  portion  of  the  clavicular  fibres  of  the  muscle. 
Having  proceeded  thus  far,  cut  through  the 
second  layer  of  deep  fascia,  avoiding  the  vein 
already  described  as  crossing  this  space,  and 
subsequently  divide  the  sterno-hyoid  and  thy- 
roid muscles  upon  a  director;  this  will  expose 
the  third  layer  of  deep  fascia  covering  the 
vessel;  a  portion  of  this  should  be  pinched  up 
by  forceps  and  an  opening  very  cautiously 
made  in  it,  after  which,  with  the  handle  of  a 
scalpel,  clear  the  artery  of  its  surrounding  cel- 
lular tissue,  draw  the  thyroid  veins  to  the  left 
side,  the  right  pneumo-gastric  nerve  and  in- 
ternal jugular  vein  to  the  right,  and  pressing 
the  left  brachio-cephalic  vein  downwards,  carry 
the  ligature  obliquely  upwards  and  inwards, 
or  from  the  right  to  the  left  side,  keeping  it 


INSECTA. 


853 


close  to  tlie  vessel  to  avoid  implicating  the 
cardiac  nerves. 

Other  plans  of  operation  have  been  recom- 
mended, but  the  above  appears  to  me  to  be  the 
best,  as  it  gives  the  surgeon  room  and  oppor- 
tunity to  see  the  state  of  parts  through  which 
he  cuts,  and  enables  him,  if  necessary,  to  tie 
either  the  subclavian  or  carotid,  or  both,  with- 
out further  trouble  or  inconvenience. 

It  has  been  recommended  to  remove  a  por- 
tion of  the  first  bone  of  the  sternum  ;  but  the 
idea  will  scarcely  be  entertained  by  any  sur- 
geon possessing  a  proper  knowledge  of  the  parts, 
or  who  is  competent  to  perform  the  operation. 

In  the  year  1827  Mr.  Wardrop  introduced 
a  new  method  for  treating  aneurisms  of  the 
inriominata  in  imitation  of  Brasdor's  plan  of 
tying  the  vessel  beyond  the  aneurismal  tumour. 
He  tied  the  subclavian  artery,  having  found  that 
the  circulation  through  the  carotid  was  very 
weak  if  not  quite  obliterated. 

The  patient  was  a-  Mrs.  Denmark.  The 
results  of  this  case  have  been  recorded  as  fa- 
vourable, but  erroneously  so.  Mrs.  Denmark 
died  in  the  year  1829  of  the  same  malady  on 
account  of  which  she  underwent  the  operation. 

Altogether  his  example  has  been  followed  in 
six  cases,  with  various  results. 

In  the  first,  Mr.  Evans,  of  Belper  in  Derby- 
shire, in  the  year  1828,  tied  the  carotid  for 
aneurism  of  the  innominata  and  commence- 
ment of  the  carotid.    The  patient  recovered. 

In  the  second,  M.  Dupuytren,  on  the  12th 
of  June,  1829,  tied  the  subclavian  for  aneu- 
rism of  the  innominata.  The  patient  died  nine 
days  afterwards. 

In  the  third,  Professor  Mott  tied  the  carotid 
for  aneurism  of  the  innominata  on  the  26th  of 
September,  1829.    The  patient  recovered. 

In  the  fourth,  Dr.  Hall,  of  Baltimore,  tied 
the  carotid  for  aneurism  of  the  inriominata  on 
the  7th  of  September,  1830.  The  patient  died 
five  days  afterwards. 

In  the  fifth,  M.  Morrisson,  of  Buenos  Ayres, 
tied  the  common  carotid  for  aneurism  of  the 
innominata  on  the  8th  of  November,  1832. 
The  patient  died  twenty  months  afterwards. 

In  the  last,  Mr.  Fearn,  of  Derby,  tied  the 
carotid  for  the  same  complaint  in  the  year  1836, 
the  circulation  through  the  subclavian  being 
almost  obliterated.  Subsequent  to  the  ope- 
ration the  patient  suffered  from  repeated  at- 
tacks of  bronchitis,  with  difficulty  of  breath- 
ing and  cough  upon  the  slightest  exertion, 
so  much  so  that  on  the  26th  of  July,  1838, 
she  was  again  placed  under  Mr.  Fearn's  care. 
That  gentleman  concluding,  after  a  careful  ex- 
amination, that,  in  consequence  of  the  circu- 
lation having  been  renewed  through  the  sub- 
clavian artery,  the  previous  operation  had  not 
cured  the  aneurism  (which  he  now  found  im- 
plicated the  commencement  of  the  subclavian 
artery)  determined  upon  placing  a  ligature 
upon  this  vessel  where  it  passes  over  the  first 
rib,  and  performed  the  operation  on  the  2d  of 
August,  1838,  apparently  with  complete  success. 

Here  then  are  the  results  of  the  two  plans 
of  operation  hitherto  performed  in  connection 
with  the  innominata.    In  Hunter's  all  the  pa- 


tients were  lost  from  repeated  hemorrhage, 
although,  as  we  have  seen  in  one  instance,  the 
individual  survived  the  operation  above  two 
months.  Mr.  Pattison,  in  his  account  of  Mr. 
Mott's  case,  appears  to  attribute  the  loss  of  the 
patient  to  the  fact  of  that  gentleman's  having 
commenced  by  exposing  the  subclavian  artery, 
thereby  depriving  the  vessel,  of  nourishment 
by  the  unnecessary  destruction  of  the  vasa 
vasorum  ;  this  might  in  some  degree  have  led 
to  the  result ;  but  I  am  more  inclined  to  be- 
lieve that  it  occurred  from  other  causes  over 
which  the  surgeon  unfortunately  has  no  con- 
troul,  I  allude  to  the  situation,  origin,  and  direc- 
tion of  the  vessel  itself.  We  have  already  ob- 
served that  it  arises  from  the  commencement  of 
the  transverse  portion  of  the  arch  of  the  aorta, 
and  is  consequently  in  adirect  line  withtheaorto- 
ventricular  opening,  being  in  point  of  direction 
the  continuation  of  the  ascending  portion  of  the 
arch  of  the  aorta.  It  thus  receives  the  undi- 
minished impetus  bestowed  upon  the  blood  by 
the  contraction  of  the  ventricle  at  a  distance, 
barely  of  three  inches  ;  hence,  when  a  ligature 
is  placed  upon  it,  the  force  of  the  ventricle  is 
directed  more  immediately  upon  this  part  of 
the  artery,  a  coagulum  can  scarcely,  if  at  all, 
be  formed  here,  and  the  ligature  being  subjected 
to  the  constant  efforts  of  the  blood  to  overcome 
it,  instead  of  ulcerating  its  way  out,  cleanly  di- 
viding the  vessels,  produces  inflammation  and 
ulceration  in  its  neighbourhood  by  constant 
friction,  and  thus  gives  rise  to  the  fatal  results. 

If  I  have  here  taken  a  correct  view  of  the 
causes  which  have  led  to  the  fatal  termination 
in  all  the  cases  where  Hunter's  method  has 
been  adopted,  (and  I  have  no  reason  to  doubt 
having  done  so,  as  we  learn  from  the  accounts 
of  the  post-mortem  examinations  both  in  Mott's 
and  Lizars'  cases,  that  the  coagulum  was  very 
imperfectly  formed,  and  that  extensive  ulcera- 
tion of  the  vessel  had  ensued  in  the  neighbour- 
hood of  the  ligature,)  I  am  quite  justified  in 
adding  that  it  is  an  operation  which  should 
never  be  performed  unless  in  those  cases  where 
it  presents  the  only  chance  of  lengthening  the 
patient's  existence. 

This  remark,  however,  does  not  apply  to  the 
plan  introduced  by  Mr.  Wardrop  in  imitation 
of  Brasdor.  Out  of  the  seven  cases  in  which 
it  has  hitherto  been  employed,  and  which  I  have 
here  cited,  three  were  successful,  and  of  the 
other  four  one  lived  for  a  period  of  twenty 
months,  and  another  (Mrs.  Denmark)  for  about 
two  years  after  the  operation. 

( H.  Hancock.) 

INSECTA. — (ivropa.;  Fr.  Insecte;  Germ. 
Insecten.)  A  class  of  Invertebrate  animals, 
which,  as  constituted  by  Linnauis,  formerly 
included  several  remarkable  groups,  which 
are  now  arranged  as  distinct  classes.  Besides 
the  true  Insecta  these  were  Crustacea,  Arach- 
nida,  and  Myriapoda.  Modern  naturalists 
have  been  almost  unanimous  in  separating 
these  groups  from  Insects,  which,  in  their  per- 
fect state,  differ  from  them  in  being  constantly 
Hexapods.  Besides  this  very  marked  character, 
Insects  differ  from  Crustacea  in  respiring  atmo- 


854 


INSECTA. 


spheric  air  by  means  of  ramified  trachea? — from 
Arachnida  in  the  body  being  constantly  divided 
into  a  distinct  head,  thorax,  and  abdomen — 
and  from  Myriapoda,  in  the  body  being  com- 
posed in  general  of  thirteen  segments. 

Insects,  therefore,  may  be  characterized  as 
a  class  of  hexapodous  invertebrate  animals, 
which  possess  antennae,  and  have  the  body  com- 
posed of  several  segments,  united  into  three 
and  sometimes  four  distinct  parts,  articulated 
together,  consisting  of  head,  thorax,  and  abdo- 
men. They  breathe  atmospheric  air  by  means 
of  lateral  spiracles  and  tracheae,  and  pass  through 
a  succession  of  changes  of  form,  or  shed  their 
external  covering  before  they  arrive  at  their 
perfect  state.  They  also  possess  other  charac- 
ters in  common  with  the  Myriapods  and  Arach- 
nidans,  as  the  circulation  of  the  nutritive  fluids 
by  means  of  a  pulsatory  dorsal  vessel,  divided 
into  distinct  chambers  or  compartments,  and 
the  respiration  of  atmospheric  air  by  means  of 
spiracular  orifices,  and  with  the  Crustaceans  in 
being  in  general  oviparous. 

Anatomically  considered,  Insects,  as  re- 
marked by  Professors  Grant*  and  Owen,f  bear 
a  remarkable  analogy  amongst  invertebrated 
animals  to  Birds  amongst  the  vertebrated.  They 
constitute  the  most  beautiful,  most  active,  and 
most  highly  organized  of  any  of  the  Inverte- 
brated classes.  Like  Birds,  they  are  inhabi- 
tants of  the  air,  the  earth,  and  the  waters,  and 
the  dominion  of  some  of  them  is  even  extended 
to  the  bodies  of  other  animals.  Physiologically 
considered,  they  also  resemble  "  the  feathered 
tribes  of  air."  Like  them  they  have  a  more 
voluminous  and  extensive  respiration,  and  a 
greater  power  of  generating  and  of  maintaining 
a  higher  temperature  of  body  than  any  other 
class  in  the  division  of  animals  to  which  they 
respectively  belong.  The  number  of  species 
is  greater  than  is  known  in  any  other  division 
of  the  animal  kingdom,  and  is  only  exceeded, 
as  in  Fishes,  by  the  almost  countless  myriads 
of  individuals  which  every  species  produces. 
The  metamorphoses  which  most  of  them  under- 
go before  they  arrive  at  the  perfect  state,  and 
are  able  to  fulfil  all  the  ends  of  their  existence, 
are  more  curious  and  striking  than  in  any  other 
class,  and  in  the  greater  number  of  species  the 
same  individual  differs  so  materially  at  its  dif- 
ferent periods  of  life,  both  in  its  internal  as 
well  as  external  conformation,  in  its  habits, 
locality,  and  kind  of  food,  that  it  becomes  one 
of  the  most  interesting  investigations  of  the 
physiologist  to  ascertain  the  manner  in  which 
these  changes  are  effected, — to  trace  the  suc- 
cessive steps  by  which  that  despised  and  almost 
unnoticed  larva  that  but  a  few  days  before  was 
grovelling  on  the  earth,  with  its  internal  organi- 
zation fitted  only  for  the  reception  and  assimila- 
tion of  the  grossest  vegetable  matter,  has  had 
the  whole  of  its  external  form  so  completely 
changed  as  now  to  have  become  an  object  of 
admiration  and  delight,  and  able  to  "  spurn 
the  dull  earth"  and  wing  its  way  into  the  open 
atmosphere,  with  its  internal  parts  adapted  only 

*  Lectures  on  Comp.  Anatomy,  Lancet,  1833-34. 
t  See  Aves,  vol.  i.  p.  246. 


for  the  reception  of  the  purest  and  most  con- 
centrated aliment,  now  rendered  absolutely 
necessary  for  the  support  and  renovation  of  its 
redoubled  energies.  But  this  condition  of 
insect  life  is  greatly  modified  in  the  different 
families.  Thus  the  most  active  species  are 
diurnal  insects,  and  are  those  which  have  the 
greatest  development  of  the  organs  of  locomo- 
tion, accompanied,  as  in  birds  of  flight,  by  a 
more  voluminous  respiration,  and  a  greater 
force  and  rapidity  of  circulation,  and  consequent 
muscular  energy  and  necessity  for  a  constant 
supply  of  food,  as  is  well  exemplified  in  the 
hive-bee  and  its  affinities.  But  although  many 
species  are  furnished  with  wings  for  flight,  these 
organs  are  not  universally  met  with  in  the 
species  of  every  order,  neither  are  they  con- 
stant in  the  two  sexes  of  the  same  species.  In 
these  instances  it  is  always  the  male  individual 
that  is  furnished  with  them.  These  exceptions 
occur  among  the  beetles,  as  in  the  glow-worm 
( Lumpyris,  Jig.  335  &  336),  in  the  Blattce 
or  cock-roaches  (Jig.  343),  in  some  species  of 
of  moths  ( Bmnbycida ),  and  in  the  plant-lice 
(Aphides ),  while  in  other  species,  the  ants,  the 
individuals  are  furnished  with  wings  only  at  a 
particular  season  of  the  year,  and  lose  them 
immediately  after  the  fulfilment  of  certain 
natural  functions.  In  each  of  these  instances, 
as  noticed  by  Mr.  Owen*  in  the  ostrich  and 
other  birds  unaccustomed  to  flight,  the  extent 
to  which  the  respiratory  organs  are  developed  is 
in  proportion  to  the  habits  of  the  species,  being 
greatest  in  those  of  flight  and  least  in  those 
which  reside  constantly  on  the  ground.  Indeed, 
so  varied  are  the  forms,  so  different  the  habits 
and  modes  of  life,  that  the  division  of  Insects 
into  families  and  tribes  has  afforded  no  small 
amount  of  difficulty  to  the  scientific  naturalist 
in  arranging  them  according  to  their  most  natu- 
ral affinities,  and  hence  a  great  variety  of  sys- 
tems have  been  proposed  for  this  purpose,  all 
of  which  perhaps  are  open  to  many  objections. 

But  it  is  not  in  the  mere  division  of  Insects 
into  families  and  tribes  that  the  philosophic 
naturalist  meets  with  the  greatest  difficulty,  but 
in  assigning  the  situation  which  the  whole 
class  ought  to  occupy  in  the  animal  kingdom, 
both  in  regard  to  Insects  themselves,  and  in 
their  relations  to  other  animals.  Whether 
naturalists  adopt  as  the  basis  of  arrangement 
the  development  and  perfection  of  the  nervous 
system  or  that  of  the  skeleton,  with  the  organs 
of  circulation  and  digestion,  as  compared  with 
similar  parts  in  other  classes,  they  have  usually 
been  led  to  admit  that  while  Insects  are  superior 
to  many  groups,  which  have  been  placed  above 
them,  in  the  former  respects,  they  are  inferior  to 
them  in  the  latter;  and  hence,  although  that 
portion  of  the  animal  body  which  is  so  all- 
important  to  active  existence,  the  nervous 
system,  is  employed  without  hesitation  as  the 
fundamental  type  and  principle  of  arrangement, 
and  in  the"  vertebrated  classes  is  scarcely  ever 
departed  from,  it  has  become  in  the  hands  of 
many  naturalists  only  of  secondary  importance 
in  the  invertebrated,  and  the  greater  perfection 

*  See  Aves,  vol.  i.  p.  341. 


INSECTA. 


855 


of  the  circulatory  and  digestive  organs  in  the 
molluscous  classes  has  induced  them  to  place 
these,  which  in  other  respects  are  inferior 
in  development,  above  the  Articulated.  We 
cannot,  however,  agree  with  those  who  consider 
the  organs  of  nutrition  alone  of  sufficient  im- 
portance to  allow  of  this  deviation  from  the 
fundamental  principle  of  arrangement,  neither 
can  we  admit  with  others  that  the  nervous 
system  of  the  higher  Articulata  is  inferior  to 
that  of  the  higher  Mollusks,  the  Cephalopoda, 
while  we  ourselves  claim  for  the  higher  Articu- 
lata the  most  decided  superiority  in  the  next 
essential  character  of  arrangement- — the  deve- 
lopment of  the  skeleton  and  organs  of  locomo- 
tion. 

Without  entering  further  upon  this  difficult 
subject,  we  will  simply  state  our  conviction 
with  Carus,  Burmeister,  and  others,  that  the 
articulated  ought  to  stand  at  the  head  of  the 
invertebrated  classes,  seeing  that  they  contain 
among  them  some  of  the  most  completely 
organized  of  invertebrated  animals.  We  shall 
reserve  for  the  present  our  explanation  of  the 
steps  by  which  we  propose  to  pass  from  the 
lowest  vertebrated  forms  to  these,  in  our  esti- 
mation, the  highest  of  the  invertebrated,  and 
proceed  to  consider  the  arrangement  of  Insects, 
as  a  class,  as  proposed  by  different  naturalists, 
before  we  enter  upon  an  examination  of  the 
peculiarities  of  these  animals. 

The  principles  upon  which  naturalists  have 
attempted  to  arrange  this  interesting  class  have 
been  almost  as  various  as  the  systems  proposed. 
Aristotle  among  the  ancients  arranged  Insects 
with  reference  to  the  presence  or  absence  of 
the  organs  of  flight ;  and  although  he  was  far 
more  successful  than  many  of  his  successors  in 
separating  from  Insects  the  Crustacea,  as  a  dis- 
tinct class,  his  arrangement  of  Insects  is  not 
entirely  natural,  since  it  separates  some  of  the 
most  nearly  connected  families.  Among  the 
moderns,  Aldrovandus,  in  the  beginning  of  the 
seventeenth  century,  divided  them  into  land  and 
water  Insects,  and  subdivided  these  groups  into 
families  according  to  the  structure  of  their 
wings  and  legs.  Swammerdam  many  years 
afterwards  first  proposed  to  arrange  Insects 
with  reference  to  their  metamorphoses ;  first, 
those  which  undergo  only  a  partial  or  incom- 
plete metamorphosis,  and,  secondly,  those  which 
undergo  a  true  or  complete  one.  The  latter  he 
again  divided  into  those  which  undergo  a  slight 
change  of  form,  but  are  active  during  the  pupa 
state  ;  secondly,  those  which  have  distinct  limbs 
but  are  inactive  in  that  condition  ;  and,  lastly, 
those  which  have  no  external  development  of 
wings  or  legs,  but  remain  as  inactive  ovate 
pupa;.  This  was  the  first  step  towards  arranging 
Insects  upon  a  truly  natural  system  ;  since,  as 
Messrs.  Kirby  and  Spence  have  justly  ob- 
served,* although  the  employment  of  the  meta- 
morphoses taken  alone  leads  to  an  artificial 
arrangement,  it  is  of  the  greatest  use  in  con- 
nexion with  characters  taken  from  the  perfect 
Insect,  in  forming  a  natural  system.  Our 
illustrious  countryman  Ray,  in  the  beginning 

*  Introd.  to  lintomol.  vol,  iv.  p.  442. 


of  the  eighteenth  century,  followed  the  example 
of  Swammerdam  in  arranging  Insects  primarily 
according  to  their  metamorphoses ;  and  Lister, 
in  1710,  followed  with  a  modification  of  Ray's 
classification,  after  which  nothing  further  was 
proposed  until  Linnajus  published  the  first  edi- 
tion of  his  Systema  Naturae  in  1735.  His  arrange- 
ment was  based  upon  the  form  and  structure  of 
the  wings.  By  these  he  divided  Insects  into  three 
groups.  First,  those  wilh  four  wings,  in  which 
he  included  in  three  divisions  those  Insects 
which  now  constitute  his  orders  Coleoptem, 
Ilemiptera,  Lepidoptera,  Neuroptera,  and  Hy- 
menoptera.  In  the  second  group  he  placed 
Insects  with  two  wings,  his  single  order  Dip- 
tera;  and  in  the  third,  Insects  without  wings, 
his  order  Aptera.  In  this  arrangement,  founded 
partly  upon  that  of  Aristotle,  Linna»us  was 
particularly  successful  in  establishing  some  very 
natural  series,  although  in  including  the  Crus- 
tacea among  his  Aptera,  like  Swammerdam 
and  Ray,  he  receded  a  little  from  a  natural 
system.  After  Linnaeus,  Degeer  and  Geoffroy 
each  proposed  a  new  arrangement,  but  it  was 
not  until  an  entirely  new  set  of  organs  had 
been  selected  by  Fabricius  that  Insects  began 
to  be  arranged  upon  truly  natural  principles. 
The  parts  from  which  Fabricius  drew  his  cha- 
racters were  those  of  the  mouth,  by  which  he 
divided  Insects  primarily  into  two  sections,  the 
Mandibulated,  or  those  furnished  with  jaws  for 
comminuting  their  food,  and  the  Haustelluted, 
or  those  which  take  their  aliment  by  means  of 
a  flexible  elongated  proboscis,  without  distinct 
manducatory  organs.  But  the  difficulty  of 
forming  a  strictly  natural  system  still  existed, 
so  long  as  the  characters  employed  were  derived 
only  from  particular  sets  of  organs,  and  not 
from  a  consideration  of  the  whole.  Cuvier,  by 
founding  his  arrangement  upon  an  examination 
of  all  the  external  organs,  and  thereby  establish- 
ing natural  families,  advanced  very  far  towards 
the  object  desired,  and  was  followed  by  La- 
treille,  Lamarck,  Dumeril,  Leach,  Kirby  and 
Spence,  and  MacLeay,  who  continued  to  im- 
prove the  arrangement  of  the  class.  These  have 
been  followed  by  Messrs.  Stephens  and  Curtis, 
and  very  recently  by  Mr.  Westwood,  the  inde- 
fatigable Secretary  of  the  Entomological  Society, 
each  of  whom  has  proposed  a  different  arrange- 
ment. But  none  of  the  systems  hitherto  pro- 
posed are  entirely  satisfactory,  so  great  indeed 
is  the  difficulty  of  discovering  the  connecting 
links  of  families,  which,  distributed  over  the 
whole  globe,  are  believed  to  include  from 
100,000  to  150,000  distinct  species;  and  this 
difficulty  will  probably  continue  until  the  in- 
ternal as  well  as  the  external  organization  is 
better  known  in  a  greater  number  of  insects 
than  it  is  at  present,  and  applied  to  their 
arrangement,  as  has  lately  been  done  by  Bur- 
meister. In  the  succeeding  pages  we  shall 
adopt  the  arrangement  of  Mr.  Stephens,  giving 
a  synoptical  view  of  the  families,  with  the 
addition  of  some  of  the  recently  established 
foreign  ones,  and  shall  also  add  particular 
descriptions  of  some  of  the  most  remarkable, 
referring  our  readers  for  more  minute  descrip- 
tions of  them  to  Mr.  Stephens's  admirable 


856 


INSECTA. 


"  Illustrations,''  and  also  to  the  valuable  work  by  Mr.  Westwood,  from  which  work  we  shall 
"  An  Introduction  to  the  Modern  Classifica-  in  part  derive  the  characters  by  which  the 
tion  of  Insects,"  now  in  course  of  publication    different  tribes  are  distinguished. 


Table  of  the  Arrangement  of  Insects  according  to  the  System  of  Mr.  Stephens. 

Class  INSECTA. 

Sub-Class  I. 
MANDIBULATA. 


CoLEOPTERA. 


Pentamera. 


Tribe  1. 
Adephaga. 
(Gluttons.) 


Tribe  2. 
Rypophaga. 
(  Cleansers.) 


Pentamera. 


Sub-tribe  1. 
Geodephaga. 
Predaceous 
ground-feeders. 


Cicindelidffi  Tiger-beetles. 
Brachinidae 
Scaritida? 

V  Carabidae,  Jig.  329,  Ground-beetles. 

Harpalida 
[  Bembidiidffi 
l_Elaphridae 


Sub-tribe  2.  "\ 
Hydradephaga.  f  Diticidse  Water-beetles. 

Predaceous     i  Gyrinidae  Whirlgigs. 
water-feeders.  J 

("Heteroceridae 

I  Parniidae 
Sub-tribe  3.  Limniidae 
Phylhydrida.    <  Helophoridoe 

Water-lovers.    |  Hydrophilidae,^g.  330,  Water-beetles. 

LSphaeridiidae 
Anisotomidae 


Sub-tribe  4. 
Necrophaga. 
Carrion-feeders. 


Helocera  1. 


Lamellicornes  2.  4 


Scaphidids 

Silphidae,  Jig.  331,  Carrion-beetles. 

Nitidulidae 

Engidae 

Paussidaa,  West. 
_Dermestidae 

{  Byrrhidae  Sand-beetles. 
\  Histeridae  Dung-beetles. 

"Lucanidae  Stag-beetles. 
Scarabaeidae 

Geotrupidae,  Jig.  332,  Dung-beetles. 
Aphodiidae 
Trogidae 

Dynastidas^/Zg.333,  Rhinoceros-beetles. 
Rutelidae 
Anaplognathidas 
Melolonthidae  Cockchaffers. 
Glaphyridae 

_Cetoniadaa  Sun-beetles. 


Subsectio  3.       *\  guprggtidgg  Gold-beaters. 
Macrosterm,  West.  (Eu^nemidffi)  WesL 

(panted  sternum).  )  E1^ridae,/g.  334,  Springing  beetles. 

rCebrionidas 
J  Cyphonidae 

I  Lampyridae Jtgs.335k,336Glow-worms 
I  Telephoridae 


Sub-sectio  4. 
Aprosterni,  West. 
Malacodermi, 
(soft  skin.) 


Melyridas 
Tillidae 
Ptinidae 
Lymexylonidae 
Bostricidae 
_Scolytida2 


Death-watches. 
Wood-borers. 


INSECTA. 


857 


Pseudo- 

Tetramera, 
West. 


o 

"Si 


v. 

OLEOPTERA.  J 

seudo-trimera, '§  l 
West.       £  ) 


C 

Pseudo 


Hetero-mera.S  4 


Dermaptera. 


Ortiioptera. 


C  Curculionidae  fig.  337  Hog- 
Rhinchophora  1 .  <  Attelabidae,  West. 

L  Salpingidae 


beetles. 


Longicornes.        Sub-sectio  2. 


Phytophaga, 
Kirby. 


{ 


Eupoda 1. 
Cyclica  2. 

Trimeri  3. 


Brachelytra. 


Newroptera 


{ 


Neuroptera.  ■< 


Panorpina  1. 
Anisoptera  2. 
Libellulina  3. 

Temitina  4. 


Megaloptera  5. 


Trichopiera. 


{Cucujidae 
Priomdae  Jig.  338  Gout-beetles. 
Cerambycidae 
Lepturidae 

Crioceridae 

r  Galerucida? 

<  Chrysomelidae^g.  339 
(.Cassidae  Helmet-beetles. 

C  Coccinellidae  Lady-Cows. 

<  Endomychidae 
(.Hispidae 


Tenebrionidae 
Blapsidae  Jig.  340 
Pimelidae 
Helopidae 
Lagriidae,  West. 
Melandryidae 
Horiidse,  West. 
Mordellidae 
GCdemeridae 
Pyrochroida? 
Cantharidae  Oil-beetles. 
Notoxid'ae 
JScydmEenidae 


fPselaphidas  ~\ 
I  Tachyporidae 

<  Staphylinidae  Jig.  341  f  Rove-beetles. 
J  Stenidae 
\_Omalidae 

Forficulidae  Earwigs. 


f  Gryllidae  Grasshoppers. 
Locustidae  Locusts. 
Achetidae  Jig.  342  Crickets. 
Phasmadae 

Mantidae,  Praying  Insects. 
_Blattidae  fig.  343  Cock-roaches. 

(  Boreidae 

I  Panorpidae  Jig.  344  Scorpion-flics. 

Ephemeridae  Jig.  345  May-Jlies. 
%  Agnonidae 

)  Libellulida3,  Dragon-flies. 


("Myrmeleonidae  Lion-ants. 
j  Hemerobidae 
J  Psocidae 
j  Raphidiidaa 
I  Mantispidae,  West. 
(JTermetidae,  White  Ants. 

f  Sialidae 
(  Perlidae 


r  Philopotamidae 

%  Leptoceridae 

(.  Phryganidae  Caddis-fii 


858 


INSECTA. 


Hymenoptera. 


IIymenoptera. 


Stiiepsiptera. 


Terebrantia  1. 


Pupophaga  2. 


Aculeata  3. 


Tubulifera  4. 


s 


Tenthredinidre  fig.  355  B.  Saw-flics. 


-v  Xipbydriidae 
C  Uroceridae 

r  Evaniidae 

J  Ichneumonidae  Ichneumon-flies. 

I  Braconidee 

VAlysiidae 

•Formicidas  Ants. 
Mutillidae 
Scoliidae 
Sapygidae 

Pompilidas  Sand-wasps. 
Sphecida? 
Larrida? 
Bembecidas 
Crabronidaa 

Vespidae  Jig.  346  Hornets  4"  Wasps. 
Apidae  Bees. 
"Andrenidaa  Sand-bees. 

r  Chrysididae  Golden  wasps. 
J  Chalcididae 
j  Proctotrupidas 
vXynipidas  Gall-flies. 


Stylopidae  fig.  347 


Sub-Class  2. 
HAUSTELLATA. 


Lepidoptera.  a 


Diurna  1. 


Crepuscularia  2. 


Pomeridiana  3. 


Nocturna  4. 


Semidiurna  5. 


Vespertina  6. 


r  Papilionidae 
\  Nymphalid 
\  Lycenid 
vHesperi 


lidae  -\ 
alidae  f 
lae  r 
idae  J 


Butterflies. 


r  Zygaenidas  -\ 
)  ShS**'  348  [  Hawk-moths. 


CiEgeriidae 

s  Hepialidae 
1  Notodontidae 
)  Bombycidae 
VArctiidae 

<  Lithosiidae 
\  Noctuidae 

C  Geometridae 

<  Platyptericidae 
C  Pyralidae 


X  Moths. 


{ 


Tortricidae 
Ypuonomeutidas 
Tineidae 
Alucitidae 


Diptera. 


("Culicidae  Gnats. 

JTipulids  Long-legs. 
Asilids  fig.  349 
Empidffi 
Dolichopidse 
Rhagionidas 
Mydasidas 

Tabanidae  Blood-suckers. 
^Bombylids 


INSECTA. 


859 


Diptera  (contin.) 


homaloptera. 
Aphaniptera. 


Anthracidae 

Acroceridae 

Stratiomydae 

Xylophagidae 

Syrphidae 

Stomoxydae 

Conopidae 

CEstndae  Gad-flies. 

Muscidae  Huuse-Jiies,  fyc. 

S  Hippoboscida:  fig.  350  Forest-flies. 
\  Nycteribidse 


Pulicidae  Fleas. 


After  a. 


Hem/ptera. 


Terrestria  1. 


_Aquatica  2. 


Homoptera. 


%  Pediculids,  Lice. 

\  Nirmidse  Jig.  351  Bird-lice. 

,-Cimicidae  Bugs. 
Pentatomidae 
Coreidae 

Reduviidae  Masked  bugs. 
Acanthiidas 
^-Hydrometridas  Skip-jacks. 

Nepidae  fig.  352  Water-scorpions. 
Notonectidae  Water-boatmen. 


/-Cicadiidae  fig.  353  Tree-hoppers. 

I  Cercopidae 

J  Psyllidae 

]  Thripidae 

I  Aphidae  Plant-lice. 

^-Coccidae 


Class  Insecta,  (Insects.) 

Animal  Invertebrated,  hexapodous,  under- 
goes metamorphoses. 

Body  in  general  winged,  and  composed  of  seg- 
ments divided  into  three  distinct  regions. 

Skeleton  external,  formed  of  the  dermal  co- 
verings. 

^nienntf  two, respiration  aerial,  sexes  distinct.' 
Sub-class  1.  Mandibulata. 

Order  I.  COLEOPTERA. 

Wings  four,  anterior  ones  (elytra)  hard,  co- 
riaceous, covering  the  abdomen,  divided  by  a 
longitudinal  suture,  not  employed  in  flight; 
posterior  ones  usually  jointed,  with  their  apex 
acute.    Metamorphosis  complete. 

The  Beetles  constitute  by  far  the  most  nu- 
merous and  varied  tribes  in  any  order,  and 
differ  as  much  in  habits  and  size  as  in  general 
form.  They  include  every  variety  of  confor- 
mation and  bulk  from  the  minute  but  rapa- 
cious Staphylinidce,  to  the  gigantic  phytopha- 
gous DynastidcE  and  Cetoniida.  So  numerous 
are  the  species  that,  according  to  Burmeister,* 
there  are  28,000  in  the  Berlin  collection  alone, 
while  the  whole  that  is  known  is  supposed  to 
exceed  36,000.  In  Mr.  Stephens's  arrange- 
ment they  have  been  divided  into  families 
which  amount  to  more  than  one-third  of  the 
whole  class,  and  these  families  are  grouped 
into  six  sections.  The  first  section  includes 
most  of  the  predaceous  beetles,  and  is  divided 

*  Manual  of  Entomology  (Translation),  p.  583. 


into  two  tribes,  Adepliaga  and  Rhypophaga, 
and  these  are  divided  into  four  sub-tribes. 

The  first  sub-tribe,  Geodephaga,  includes  the 
predaceous  Ground-beetles,  which  are  cha- 
racterized by  the  elegance  of  their  form  and 
alacrity  of  their  movements.  They  have  six 
projecting  palpi,*  their  mandibles  are  strong, 
curved,  and  pointed,  and  their  legs  slender 
and  formed  for  running,  (fig.  329.)    Some  of 


Fig.  329. 


Carabiis  monilis,  (  Ground-beetle,  male. ) 

*  The  third  pair  of  palpi  are  maxillary,  and  arc 
the  analogues  of  what  we  shall  hereafter  describe 
as  the  Galea. 


860 


INSECTA. 


this  division,  the  Cicindelida,  are  extremely 
voracious,  and  most  of  them  feed  upon  dead 
animal  substances,  although  some  of  the  Hur- 
palida  are  known  to  be  vegetable  feeders. 
The  second  sub-tribe,  Hydradephaga,  includes 
the  predaceous  water-beetles,  and  the  third, 
Philhydrida,  a  variety  of  families  allied  to 
each  other  by  similarity  in  general  structure, 
by  inhabiting  water  or  damp  situations,  and  by 
subsisting  upon  decaying  animal  and  vegetable 
substances,  fungi,  &c.  Amongst  the  aquatic 
species  is  one  of  the  largest  British  beetles, 
Hydrous  piceus  (Jig.  330). 

Fig.  330. 


Hydrous  piceus,  (  Great  water -beetle,  male.) 

All  the  water-beetles  are  characterized  by  their 
four  posterior  legs  being  formed  peculiarly  for 
swimming ;  they  are  ciliated  along  the  tarsal 
joints,  the  last  of  which  is  furnished  with  a 
very  minute  claw.  The  insects  of  the  third 
sub-tribe,  the  predaceous  water-beetles,  Dyti- 
cit&e,  are  distinguished  from  those  of  the  second 
by  the  latter  having  long  and  slender  instead 
of  clavated  antennae,  and  by  their  possessing 
six  instead  of  only  four  palpi.  The  males  of 
both  sub-tribes  have  one  or  more  joints  of  their 
anterior  tarsi  (Jig.  330,  A.)  very  much  dilated, 
by  means  of  which  they  attach  themselves 
strongly  to  the  females.    Their  larva  are  active 

Fig.  331. 


and  voracious.  The  fourth  sub-tribe,  Necro- 
p/taga,  includes  the  carrion  and  burying-beetles 
(Jig.  331),  so  called  from  their  habit  of  bury- 
ing small  dead  animals  in  the  ground,  by 
digging  away  the  earth  from  beneath  them, 
and  thus  allowing  them  to  sink  down,  and 
then  depositing  their  eggs  in  the  bodies.  The 
genera  of  this  division  differ  considerably  from 
each  other,  but  may  be  characterized  as  in 
general  possessing  abruptly  clavated  antennas, 
an  oval  or  oblong  body,  with  the  elytra  often 
truncated,  and  the  legs  strong  and  formed  for 
running. 

The  second  section  is  also  divided  into  four 
tribes,  which  include  insects  of  different  habits 
and  conformation. 

In  the  first  tribe,  Helocera,  the  insects  are 
of  an  oval  shape,  and  have  the  antennas  geni- 
culated,  and  terminated  by  an  oval  club. 
Their  legs  are  flattened,  broad,  and  formed  for 
burrowing,  and  are  terminated  by  very  minute 
tarsi.  Their  bodies  are  exceedingly  hard  ;  they 
feed  upon  decaying  animal  matter,  and  when 
touched  simulate  the  appearance  of  death. 

The  second  tribe,  Lamellicornes,  are  a  very 
natural  group.  They  are  distinguished  by  the 
club  of  the  antennae  being  divided  into  plates 
or  lamellae.  Their  legs  are  thick,  strong,  and 
deeply  notched,  and  the  tarsi  of  the  anterior 
pair  in  some  families  are  very  minute.  They 
are  either  stercoraceous  or  vegetable  feeders, 
subsisting,  like  the  common  dung-beetle,  Geo- 
trupes  stercorarius*  (Jig.  332),  upon  deeom- 

Fig.  332. 


Necropltorus  vespillo,  (  Burying-beetk J. 


Geotrupes  stercorarius,  (  Dung-beetle ). 

posing  vegetable  substances,  or  like  the  chaffer- 
beetles,  Melolonthidcc,  upon  the  foliage  of 
shrubs  or  trees,    or  like   the  Dynastidisf 

*  This  drawing  is  of  a  specimen  captured  by  the 
writer  of  the  present  article  in  the  summer  of  1829, 
and  affords  a  curious  instance  of  malformation  of 
the  anterior  extremities  with  the  tibias  lunated  and 
acuminated,  without  dentations,  the  tarsi  entirely 
wanting.  It  is  now  in  the  cabinet  of  the  Rev.  F. 
W.  Hope. 

t  It  is  asserted  that  the  Dyttastes  Hercules  grasps 


INSECTA. 


861 


(fig.  333)  upon  the  sap  that  flows  from  the  The  third  tribe,  Macrosterni,  Westw.  in- 
wounded  bark  or  roots.  eludes  a  family  of  insects,  Elaterida,  (Jig.  334), 

Fig.  333.  Fig.  334. 


Dynastes  Hercules. 

,  the  epicranium  ;  b,  the  clypeus ;  c,  labrum ;  d, 
mandibles  •,  e,  maxilla  and  palpi  ;/,  labial  palpi ; 
</,  antenna;;  h,  tbe  eye;  i,  prothorax  and  born; 
k,  scntellum  ;  I,  elytra  ;  m,  abdomen;  n,  femur; 
o,  til)ia ;  p,  the  tarsus;  q,  unguis. 


Elater  noctilucus,  ( Click-beetle,  female.)  West-Indian 
Jire-beetle. 

or  springing-beetles,  which  are  commonly 
known  in  their  state  of  larvae,  as  the  wire-worm, 
and  are  often  exceedingly  injurious  to  meadows 
and  corn-fields.  In  some  counties  many  acres 
of  meadow-land  have  occasionally  been  de- 
stroyed by  these  insects  attacking  the  roots  of 
the  grass,  which  then  quickly  perishes.*  They 
are  characterized  in  their  perfect  state  by  having 
an  elongated  body,  with  the  head  sunk  deeply 
into  a  notch  in  the  prothorax ;  by  their  fan-shaped 
or  seriated  antenna?,  and  by  a  long  spine  or  pro- 
cess directed  backwards  from  the  pro-sternum  or 
under-surface  of  the  prothorax,  and  received 
into  a  groove  in  the  meso-sternum.  By  means 
of  .this  spine  they  are  enabled,  on  bending  the 
body  and  then  suddenly  retracting  it,  to  spring 
to  a  considerable  distance.  From  this  act  they 
have  derived  their  name.  Some  species  of  the 
family  are  remarkable  for  shining  brilliantly  at 
night,  and  are  the  noted  fire-flies  of  the  West 
Indies. 

In  the  fourth  tribe,  Aprosterni,  Westw., 
there  are  insects  equally  curious  and  destruc- 
tive as  in  the  preceding.  The  true  Aprosterni 
are  distinguished  chiefly  by  their  soft  flexible 
elytra,  by  an  entire  absence  of  any  process 
from  the  sternal  surface  of  the  prothorax,  and 
by  the  dilatation  of  the  margins  of  the  pro- 

the  branch  of  a  tree  between  its  frontal  (a)  and 
thoracic  horn  ( i ),  and  then  whirls  itself  round  to 
cut  through  the  bark  and  occasion  a  flow  of  sap, 
upon  which  the  insect  is  said  to  subsist.  Impro- 
bable as  the  statement  appears,  from  the  circum- 
stance that  the  thoracic  horn  is  wanting  in  the 
female,  we  were  once  assured  of  its  correctness, 
by  a  gentleman  who  affirmed  to  us  he  had  witnessed 
the  fact.  A  similar  act  is  attributed  to  the  male 
stag-beetle,  Lucanus  cervus,  which  is  furnished  with 
mandibles  nearly  half  the  length  of  its  whole  body, 
while  in  the  female  they  are  not  larger  than  in  other 
insects  of  the  same  size. 

*  The  Rev.  F.  W.  Hope  has  ascertained  that  the 
larva;  of  this  family  were  exceedingly  destructive 
to  the  potato  crops  in  the  West  of  England  during 
the  summer  of  1838,  an  account  of  which  was 
read  at  the  meeting  of  the  Entomological  Society, 
April  1st,  1839. 


862  INSECTA. 

thorax,  which  anteriorly  covers  the  base  of  the 
head.  Some  exceptions  exist  to  these  charac- 
ters in  the  Bostricida  and  their  congeners, 
which  ought  perhaps  to  be  removed  to  another 
tribe.  In  the  Lampyrida  (glow-worms),  (figs. 
335  and  336),  there  is  an  example  of  a  circum- 


Fig.  337. 


Fig.  335. 


Fig.  336. 


Male.  Female. 
Lampyris  rwctiluca,  (  Glow -worm ). 

stance  not  uncommon  among  insects,  the  pos- 
session of  wings  by  the  male  sex  and  their 
entire  absence  in  the  female.  The  Ptinidte  or 
death-watches,  and  other  Xylophagous  insects 
of  this  tribe,  although  small,  are  exceedingly 
destructive  to  furniture  and  the  wood  of  houses; 
and  the  Bostricida  and  Scolytidtc  to  living  trees. 
It  is  an  insect  of  this  family,  Scolytus  de- 
structor, that  of  late  years  has  occasioned  in- 
calculable mischief  to  the  elms  in  St.  James's 
Park  and  Kensington  Gardens,  and  in  the 
park  at  Brussels.  So  lately  as  the  summer  of 
1836  nearly  eighty  fine  elms  were  cut  down  at 
the  latter  place  and  its  neighbourhood,  in  con- 
sequence of  decay  occasioned  by  this  pest.* 
Another  species  S.  pygmteus,  which  attacks 
the  oak,  has  destroyed  many  thousands  of 
young  trees  in  the  Buis  de  Vincennes.f  Ano- 
ther genus,  Tomicus  typographus,  was  so  de- 
structive in  the  Hartz  Forest  in  Germany  du- 
ring a  series  of  years  from  the  beginning  of  the 
last  century  to  1783,  that  the  number  of  trees 
destroyed  by  it  in  that  forest  alone  was  calcu- 
lated at  a  million  and  a  half.J 

In  the  third  section,  Pseudo-tetramera, 
WESTw.,the  species  have  one  false  and  four  dis- 
tinct tarsal  joints  to  their  legs,  with  pulvilli  or 
hairy  cushion  on  their  under  surface,  and  the 
ante-penultimate  joint  is  bilobed  and  broader 
than  the  others.  The  section  is  divided  into  two 
tribes. 

In  the  first  tribe,  Rhynchophora,  (fig.  337), 
the  head  is  elongated  in  the  form  of  a  snout  or 
rostrum,  at  the  extremity  of  which  is  the  mouth, 
and  at  the  sides  are  inserted  the  antenna  which 
are  usually  geniculated  and  club-shaped.  The 
larva?  of  these  insects  are  generally  apodal, 
and  many  species  are  exceedingly  injurious  to 
the  blossoms  of  the  apple,  pear,  and  other 
fruit-trees.  Both  the  larva  and  perfect  indi- 
vidual of  one  minute  species,  well  known  as 
the  "  weevil,"  Culandra  grunaria,  closely  al- 
lied to  fig.  337,  occasion  immense  losses  in 
the  storehouses  of  the  factor  by  attacking  and 
destroying  his  corn.    The  parent  insect  not 

*  Trans.  Ent.  Society,  vol.  ii.  p.  xvi. 

f  Annal.  Soc.  Ent.  France.  1836,  pp.  xvi.  and 
xxx.  1837,  p.  iv. 

%  Latreille,  Hist.  Nat.  torn.  ii.  Gmelin,  A  fa- 
hand,  iiber  die  Wurmtroekniss.  Lcipz.  1787.  West- 
wood,  Introduction,  &c.  vol.  i.  p.  352. 


Calandra  longipes,  male. 

only  feeds  upon  the  corn  itself,  but  deposits  a 
single  egg  in  every  grain,  and  the  larva  when 
hatched  devours  the  whole  excepting  the  husk. 
The  second  tribe,  Longicomes,  (fig.  338), 

Fig.  338. 


Cerambyx  latipes. 

are  known  chiefly  by  the  great  length  of  the 
antenna?,  which  usually  exceeds  that  of  the 
whole  body.  Their  mandibles  are  strong  and 
pointed  ;  the  body  elongated  and  depressed  ; 
and  the  prothorax,  which  is  often  tuberculated 
or  spined,  is  narrower  than  the  abdomen. 
Their  larvae  are  short,  thick,  and  apodal,  and 
are  furnished  with  strong  mandibles,  and  live 
beneath  the  bark  or  in  the  wood  of  trees. 

The  third  tribe,  Phytophaga,  Kirby,  is  also 
composed  of  pseudo-tetramerous  insects,  with 
pulvilli  on  their  tarsi,  and  is  divided  into  two 
sub-tribes.  In  the  first,  Eupoda,  the  body  is 
of  an  elongated  oval  form,  the  head  is  sunk 
deeply  into  a  narrow  prothorax,  and  the  thighs 
of  the  posterior  legs  are  greatly  enlarged.  In 
the  second  sub-tribe,  Cyclica,  the  body  is  of  a 
rounded  or  oblong  oval  (fig.  339),  the  base 
of  the  prothorax  is  narrower  than  that  of  the 
elytra,  and  the  antenna?,  which  are  of  moderate 
length,  are  inserted  widely  apart  from  each 


INSECTA. 


863 


Fig.  339. 


Timurcha  tenebricosa. 


other.  It  is  an  insect  of  this  tribe,  Haltica 
nemorum,  that  often  occasions  so  much  injury 
to  the  agriculturist  by  destroying  his  crops  of 
turnips  immediately  after  the  young  plant  ap- 
pears above  ground.  The  perfect  beetle, 
scarcely  larger  than  a  millet-seed,  deposits  its 
eggs  upon  the  under  surface  of  the  first  leaves, 
and  the  larva  when  hatched  penetrates  into  the 
substance  of  the  parenchymatous  tissue,  be- 
tween the  cuticle  of  the  upper  and  under  sur- 
face of  the  leaf,  where  it  lives  until  it  is  ready 
to  undergo  its  transformations  in  the  ground.* 
In  some  years  the  plants  are  attacked  by  such 
prodigious  numbers  of  these  insects  that  many 
thousand  of  acres  are  destroyed  in  a  few  days. 
The  loss  sustained  by  the  devastations  of  this 
insect  in  Devonshire  in  1786,  is  said  to  have 
been  not  less  than  £100,000  \ 

In  the  fourth  section,  Pseudo-trimera,  West. 
the  insects  have  only  three  distinct  joints  in 
their  tarsi,  although  a  fourth  one,  exceedingly 
minute,  and  which  like  the  additional  one  in 
theTetramera  was  first  noticed  by  Messrs.  Kirby 
and  Spence,J  exists  at  the  articulation  of  the  last 
joint, as  in  the  insects  of  the  third  section.  The 
Pseudo-trimera  are  distinguished  by  their  tarsi, 
by  their  oval  or  hemispheric  shape,  and  by  the 
antennae  ending  in  a  three-jointed  club.  The 
larvae  are  hexapodous  and  active ;  those  of  the 
common  lady-cow,  Coccinella,  feed  upon 
aphides,  and  other  genera  upon  fungi. 

In  the  fifth  section,  Heteroniera,  there  are 
five  joints  in  the  first  and  second  pairs  of  legs, 
but  only  four  in  the  third,  (jig.  340).  The 
palpi,  four  in  number,  are  large  and  projecting, 
and  the  antennae,  usually  filiform  or  monili- 


Fig.  340. 


Blaps  mortisaga,  ( Darkling-beetle). 


*  Le  Keux,  Trans.  Ent.  Society,  vol.  ii.  p.  24. 
t  Kirby  and  Spence,  Introduct.  to  Entom.  vol.  i. 
p.  185. 
{  Id.  vol.  iii.  p.  683,  4. 


form,  are  never  terminated  by  a  pectinated  club. 
It  includes  many  genera  of  dissimilar  habits, 
the  darkling-beetles,  Blapsida,  the  meal-bee- 
tles, Tenebrionidte,  and  the  Cantharida,  the 
oil-beetles  and  blister-flies. 

In  the  sixth  section,  Brachelytra,  (fig.  341), 


Fig.  341. 


Creophilus  maxillosus,  (  Rove-beetle ). 

the  body  is  elongated,  and  terminated  by  two 
exsertile  papillae,  the  elytra  short,  quadrate, 
and  often  covering  only  the  meso-  and  meta- 
thorax ;  the  true  or  posterior  wings,  folded  be- 
neath the  elytra ;  head  broad  and  flattened, 
mandibles  large,  hooked,  and  pointed,  antennae 
often  enlarged  towards  their  extremities,  and 
the  tarsi  of  all  the  legs  five-jointed.  The 
larvae  are  active  and  voracious,  and  undergo  a 
complete  metamorphosis. 

The  situation  assigned  to  this  group  of  in- 
sects by  different  systematists  has  varied  con- 
siderably. Many  authors  have  placed  them 
with  the  pentamerous  insects,  unto  which  from 
their  habits  and  number  of  joints  in  their  tarsi 
they  appear  to  belong.  Thus  Dejean  assigned 
them  a  position  between  the  Hydr'adephaga 
and  Phylhydrida ;  Dr.  Leach*  between  the 
Silphida  and  Dermestida ;  Mr.  Kirby,  in  his 
recent  work,f  between  the  Adephaga  and 
Necrophaga;  and,  lastly,  Mr.  Westwood  J 
between  the  Dermestida  and  Byrrhida.  On 
the  other  hand  Mr.  Stephens,  after  Linne  and 
Fabrieius,  has  placed  them  at  the  end  of  his 
Coleoptera,  thinking,  probably,  as  Mr.  Kirby 
has  remarked,  that  they  are  connected  with  the 
following  orders,  Dermaptera  and  Orthoptera, 
by  their  abbreviated  elytra,  and  by  their  anal 
papillae  or  styles ;  as  they  are  also,  probably, 
by  the  shortness  and  structure  of  their  alimen- 
tary canal,  which  in  many  respects  as  much 
resembles  that  of  the  ForficulidcE  or  Blattidce, 
as  the  Adephaga  or  Necrophaga. 

Order  II.  DERMAPTERA. 

Wings  four,  anterior  ones  (elytra)  crustace- 
ous,  quadrate,  and  divided  by  a  straight  suture; 
not  employed  in  flight ;  posterior  ones  mem- 
branous, folded  longitudinally  and  transversely, 
only  partially  covered  by  the  elytra;  anus 
armed  with  large  moveable  forceps.  Larva 
active,  resembles  the  perfect  insect.  Metamor- 
phosis incomplete. 

The  single  family  of  this  order,  Forficulida, 
(Earwigs)  are  readily  distinguished  from  the 

*  Article  Entomology,  Edin.  Encycl.  vol.  ix. 
f  Insects,  Fauna  Borcali -Americana,  p.  85  et 
seq.  1837. 

X  Introduc.  to  the  Modern  Classification  of  In- 
sects, &c.  1838-9. 


864 


INSECTA. 


Brachelytra  by  tire  forcipated  anus,  the  great 
length  of  the  antennae,  and  the  breadth  and 
circularity  of  the  wings  when  expanded,  com- 
pared with  the  narrow  and  acute  ones  of  the 
latter  insects. 

Order  III.  ORTHOPTERA. 

Wings  four,  anterior  ones  coriaceous,  reticu- 
lated, and  overlapping  each  other,  posterior 
ones  partly  coriaceous  partly  membranous,  re- 
ticulated, and  folded  longitudinally;  head  ver- 
tical ;  mandibles,  thick,  strong,  and  dentated ; 
palpi  four,  maxillary  ones  in  most  genera  five- 
jointed.  Metamorphosis  incomplete.  The  larvae 
are  active,  and  resemble  the  perfect  insect. 

In  this  Order  are  included  many  remarkable 
families.  The  Locust id<e,  Locusts ;  the  Ache- 
tidic,  the  House  and  Mole-crickets  (fig.  342) ; 


Fig.  342. 


Gryllotalpa  vulgaris,  ( male ).  Mole-cricket. 


the  Mantida,  or  praying  insects  ;  and  the  Blat- 
tidce  (fig.  343),  or  destructive  Cock-roaches. 

Fig.  343. 


Blutta  Orientals  (male.)    The  Ccck-rOach. 


Order  IV.  NEUROPTERA. 

Wings  four,  linear,  naked,  membranaceous, 
and  minutely  reticulated ;  all  employed  in 
flight;  head  large,  eyes  projecting ;  body  linear. 

This  Order  is  divided  into  five  sections. 

In  the  first  section,  Panorpina,  or  Scorpion- 
flies  (fig.  344),  the  head  is  produced  anteriorly 


Fig.  344. 


Panorpa  communis  ( male ).  Scorpion-fly. 
(  Samouelle.J 

into  a  short  rostrum,  at  the  extremity  of  which 
is  the  mouth,  as  in  some  of  the  Curculionida: ; 
the  antenna;  are  long  and  filiform,  and  the 
body  is  slender,  and  terminates  in  the  female 
in  an  acute  ovipositor,  and  in  the  male  in  an 
articulated  claw  (a)  like  the  tail  of  the  Scor- 
pion, from  which  the  insect  derives  its  name. 
The  larva  is  unknown,  but  is  supposed  to  un- 
dergo a  complete  metamorphosis.  The  pupa 
or  nymph  is  inactive.*  The  perfect  insect  is 
predaceous. 

In  the  second  section,  the  Anisoptera  or  Ephe- 
meridtE,  May-flies  (fig.  345),  are  distinguished 


Fig.  345. 


Ephemera  vulgata.    May-fly.    ( Samouelle.) 

by  the  smallness  of  their  posterior  wings,  by  the 
shortness  of  the  antenna;,  and  by  the  long  setae 
at  the  extremity  of  the  abdomen.  The  larvae 
are  active,  and  much  resemble  the  perfect  in- 
sect. They  reside  constantly  beneath  stones, 
or  in  burrows  at  the  bottom  of  running  streams,! 
and  undergo  an  incomplete  metamorphosis. 
The  pupa  is  active  like  the'  larva.  In  the  per- 
fect insect,  which  takes  no  food,  and  is  prover- 
bially noted  for  the  shortness  of  its  existence, 
which  is  seldom  more  than  a  few  hours,  the 
parts  of  the  mouth  are  almost  entirely  oblite- 
rated. 

In  the  third  section,  Libellulina,  Dragon- 
flies,  all  the  wings  are  of  equal  size,  eyes  large 
and  prominent,  antennae  minute,  body  slender, 

*  Westwood,  Introduction  to  Entomology,  vol. 
ii.  p.  53. 
t  Ibid.  vol.  ii.  p.  29. 


INSECTA. 


8G5 


and  tarsi  with  only  three  joints.  The  larva 
and  pupa  are  active,  voracious,  and  aquatic,  and 
like  those  of  the  Ephemera,  resemble  the  per- 
fect insect.    Metamorphosis  incomplete. 

The  fourth  section,  Termitina,  have  large 
and  nearly  equal  sized  wings,  either  disposed 
horizontally  or  erect,  with  the  antennae  rather 
long  and  filiform,  as  in  Hemerobidee,  lace- 
winged  flies,  or  club-shaped,  as  in  the  ant-lions, 
Myrmelionida ■.  The  larvae  are  active  and  pre- 
daceous.  The  ant-lion  lives  at  the  bottom  of  a 
minute  pit-fall,  which  it  digs  to  entrap  other 
insects.  The  Hemerobius  lives  among  crowds 
of  Aphides,  plant-lice,  upon  which  it  feeds, 
while  the  larvae  of  the  Termites,  or  white  ants, 
live  in  societies  of  almost  innumerable  indivi- 
duals. The  first  two  of  these  families  undergo 
a  complete  metamorphosis,  and  the  insects  in 
the  condition  of  nymphs  are  inactive  in  the 
earlier  stages  of  the  pupa  state.  In  the  latter 
family  the  larva  and  pupa  greatly  resemble  the 
perfect  insect,  and  are  active  at  every  period  of 
existence. 

The  fifth  section,  Megaloptera,  have  the  pos- 
terior wings  rather  larger  than  the  anterior,  the 
head  and  pro-thorax  large  and  quadrate,  and 
the  antennae  long  and  setaceous.  Metamor- 
phosis incomplete.  According  to  Mr.  West- 
wood  *  the  larva  and  pupa  are  active,  and  not 
inclosed  in  a  case,  are  aquatic,  and  greatly  re- 
semble the  perfect  insect. 

Order  V.  TRICHOPTERA. 

Wings  four,  deflexed,  hairy,  not  reticulated  ; 
texture  slightly  coriaceous  ;  posterior  pair  pli- 
cated, broader  than  the  anterior;  antennae  very 
long,  setaceous  ;  ocelli  three  ;  maxillary  palpi 
long  ;  "  mouth  unfitted  for  mastication  ;  man- 
dibles rudimental."    Metamorphosis  complete. 

The  perfect  insects  of  this  Order,  called  by 
fishermen  "  stone-flies,"  \  are  found  on  water- 
plants,  stems  of  trees,  and  palings  by  the  side 
of  rivers.  The  larvae,  the  caddis,  or  case-worms, 
are  aquatic,  and  reside  in  little  cases  which 
they  carry  about  with  them,  and  construct  by 
uniting  bits  of  wood,  minute  shells,  and  frag- 
ments of  stones,  which  are  woven  together  with 
threads  of  fine  silk.  The  pupa  is  semi-com- 
plete, and  quiescent  during  the  greater  part  of 
its  period,  but  becomes  active,  and  creeps  out 
of  the  water  upon  the  stems  of  plants  before 
changing  to  the  perfect  insect. 

Order VI.  HYMENOPTERA. 
Wings  four,  membranous  with  large  areolar 
cells;  posterior  pair  smaller  than  the  anterior; 
antenna;  longer  than  the  head  ;  eyes  large ; 
ocelli  three.  Mandibles  strong,  and  generally 
dentated  ;  maxillae  largely  developed  ;  labium 
and  ligula  together  forming  a  long  proboscis 
sheathed  by  the  maxillae.  Female  armed  either 
with  a  borer  or  sting.  Metamorphosis  com- 
plete. 

This  Order  is  divided  into  four  sections. 
In  the  first,  Terebrantia,  borers,  the  abdo- 
men is  sessile  or  united  to  the  thorax  by  its 

*  Introdnct.  to  Entom.  vol.  ii.  p.  23. 
t  YarreU's  British  Fishes,  vol.  ii.  p.  84. 
VOL.  1 1 . 


whole  breadth.  In  one  family,  the  saw-flies, 
(fig.  355,  d),  the  abdomen  is  armed  with  two 
serrated  partially  concealed  plates,  with  which 
the  insect  cuts  through  the  bark  or  pierces  the 
leaves  of  plants  to  deposit  her  eggs.  In  ano- 
ther family,  Urocerida,  the  true  borers,  the  ab- 
domen is  armed  with  a  strong  projecting  cylin- 
drical spiculum,  which  is  grooved  on  its  under 
surface,  and  contains  two  smaller  dentated  spi- 
cula,  analogous  to  the  plates  of  the  saw-fly, 
with  which  the  insect  bores  into  timber- 
trees  and  deposits  its  eggs.  The  larvae  are 
active  and  extremely  voracious.  Those  of  the 
saw-flies,  pseudo-caterpillars  (Jig.  355,  a,)  de- 
vour the  leaves  of  plants,  and  are  sometimes 
exceedingly  injurious  to  the  agriculturist,  as 
has  been  the  case  with  those  of  Athalia  eenti- 
folice  to  the  turnip  crops  during  the  last  few 
summers,*  while  the  larvae  of  Urucerida  are  said 
to  be  equally  destructive  to  living  trees.f 

In  the  second  section,  Pnpophaga,  the  ich- 
neumon flies,  the  body  is  long  and  slender,  and 
the  abdomen  is  petiolated,  or  connected  only 
by  a  constricted  neck  with  the  thorax,  and  the 
antennae  are  long  and  setaceous.  The  larvae  are 
apodal,  and  are  parasitic  on  other  insects. 

In  the  third  section,  Aculeata,  the  body  is 
short  and  pedunculated,  and  furnished  with  a 
true  aculeus,  which  is  used  as  a  weapon  of  de- 
fence. The  larvae  are  apodal,  are  fed.  by  the 
parent  or  by  sterile  females,  and  generally  re- 
side in  cells.  Some  species  are  solitary,  and 
feed  their  young  with  the  bodies  of  other  in- 
sects, Crabronida  ;  others  live  in  society,  and 
are  either  omnivorous,  as  the  Formicidit,  ants, 
and  Vespida,  hornets  (fig.  346)  and  wasps,  or 

Fig.  346. 


Vespa  crabro.    The  Hornet.    ( Samouelle.) 


mellivorous,  as  the  humble  and  hive  bees, 
(Apida ),  which  feed  their  young  upon  a  mix- 
ture of  pollen  and  honey. 

In  the  fourth  section,  Tubitlifera,  the  body 
is  short,  slightly  convex,  and  often  compressed 
laterally ;  the  posterior  wings  are  almost  en- 
tirely destitute  of  nervures,  and  the  abdomen  is 

*  Prize  Essay  of  the  Entomological  Society  on 
the  Anatomy,  Habits,  and  Economy  of  Athalia 
centifolia,  1838,  by  G.  Newport. 

t  Westwood,  Introd.  &c.  vol.  ii.  p.  119.  Mr. 
Ruddon  in  Trans.  Entomological  Society,  vol.  i. 
p.  Ixxitv. 

3  L 


866 


INSECTA. 


furnished  either  with  a  telescopic,  jointed  tube, 
as  in  the  Chrysidida,  golden  wasps,  or  with  a 
spiculiferous  ovipositor,  which  is  partly  retrac- 
tile within  the  abdomen,  as  in  the  Cynipidte, 
gall-flies.  The  former  of  these  insects  deposit 
their  eggs  either  in  the  cells  of  other  Hymen- 
optera  or  in  the  bodies  of  active  Lepidopterous 
larvae,  before  their  change  to  the  pupa  state,  and 
thus  resemble  in  habits  the  true  Ichneumonidcc. 
The  Cynipida  puncture  the  leaves  or  bark  of 
trees  and  plants,  and  deposit  their  eggs,  at  the 
same  time  injecting  into  the  wound  a  fluid 
which  occasions  the  growth  of  galls  or  excre- 
scences, the  interior  of  which  is  both  food  and 
habitation  for  the  young  larva.  In  their  habits, 
as  Mr.  Westwood  has  well  observed,  the  Cyni- 
pida very  closely  approach  the  Terebrantia, 
and  seem  to  form  a  link  of  communication  be- 
tween them  and  the  true  lchneumunida. 

Order  VII.  STREPSIPTERA. 

Wings  four,  the  anterior  ones  (pseudelytra) 
very  minute,  twisted,  and  projecting  trans- 
versely from  the  sides  of  the  meso-thorax  like 
little  scales ;  posterior  pair  very  large,  fan- 
shaped,  with  radiating  nervures,  and  plicated 
when  folded.  Body  linear,  abdomen  com- 
pressed, metathorax  very  large  ;  meso-  and  pro- 
thorax  very  short ;  head  transverse,  broader 
than  the  pro-thorax;  eyes  slightly  peduncu- 
lated ;  antennae  inserted  into  an  exca- 
vation in  the  front,  and  terminated  by  two 
branches ;  mouth  unfitted  for  taking  food ; 
maxillae  minute,  projecting,  stiliform  ;  labial 
palpi  very  large.*    Metamorphosis  complete. 

These  insects,  Stylopida;  are  parasitic  and 
exceedingly  minute  ;  they  undergo  their  trans- 
formations in  the  bodies  of  perfect  wasps  and 
bees,  and  pass  out  between  the  abdominal  seg- 
ment. Latreille  has  aptly  designated  them  the 
CEstri  of  insects.  It  is  entirely  unknown  where 
the  eggs  are  deposited,  whether  in  the  body  of 
the  wasp  or  bee,  or  in  that  of  its  larva.  Four 
distinct  genera  of  these  minute  parasites  have 
already  been  discovered.  Stylops  Spencii  (Jig. 
347)  is  one  of  the  largest  species,  but  is  scarcely 

Fig.  347. 


Stylops  Spencii,  highly  magnified. 
Westwuod,  Ent.  Tram. 

*  Kirby  i"  Lin.  Trans,  vol.  xi.  p.  86.  Kirby 
auii  Spence,  Introduct.  vol.  iv.  p.  378. 


more  than  two  lines  in  length,  while  the  small- 
est species  yet  known,  Elenchm  Templetonii, 
West.*  is  not  more  than  two-thirds  of  a  line, 
or  scarcely  a  line  in  breadth  with  its  wings  ex- 
panded. 

The  anomalous  structure  of  these  insects  has 
been  a  matter  of  great  difficulty  to  entomolo- 
gists. Rossi,  who  first  discovered  an  insect  of 
this  order,  placed  it  with  the  Ilymenoptera. 
Mr.  Kirby  at  first  thought  that  it  ought  to  follow 
the  Coleoptera,  on  account  of  its  elytra  and 
kind  of  metamorphosis ;  Mr.  Mac  Leayf  placed 
it  between  the  Coleoptera  and  Hymenoptera, 
to  both  of  which,  as  Mr.  Kirby  had  remarked, 
it  is  connected  by  its  metamorphosis.  Dr. 
Leach  placed  it  between  the  Coleoptera  and 
Dermaptera,  while  Mr.  Newman,  who  at  first 
thought  it  belonged  to  Hymenoptera,  }  afterwards 
placed  it  with  the  Diptera,§  between  which 
two  Orders  it  was  also  placed  by  M.  Samo- 
uelle.||  It  has,  however,  been  satisfactorily 
shown  by  Mr.  Westwood H  that  it  is  an  imper- 
fectly mandibulated  insect,  and  that  if  the 
structure  of  its  oral  apparatus,  the  shortness  of 
its  first  thoracic  segments,  and  its  kind  of  me- 
tamorphosis be  considered,  it  ought  to  be 
placed  between  the  Ilymenoptera  and  Lepi- 
doptera,  at  the  end  of  the  Mandibuluta,  which 
situation  it  occupies  in  Mr.  Stephens's  arrange- 
ment.** But  the  existence  of  elytra,  and  the 
peculiar  structure  of  its  wings,  ought  not  to  be 
disregarded,  and  should  any  species  sufficiently 
large  for  minute  dissection  be  hereafter  disco- 
vered, it  is  not  improbable  that  an  examination 
of  its  internal  organs  may  lead  to  a  different 
opinion. 

Sub-Class  II.  HAUSTELLATA. 

Order  VIII.  LEPIDOPTERA. 

Wings  four,  covered  with  minute  scales ; 
mouth  proboscidal,  formed  of  two  elongated 
organs,  approximated  laterally  to  form  a  tube  ; 
when  at  rest  spirally  convoluted.  Labial  palpi 
large,  hairy.    Metamorphosis  complete. 

The  Order  is  divided  into  six  sections. 

First  the  Diurna,  day-fliers  or  butterflies,  are 
distinguished  by  their  long  clavated  antennae, 
which  in  a  few  are  also  slightly  hooked  at  the 
apex.  The  wings  are  large  and  erect  when  the 
insect  is  at  rest.  The  larva  or  caterpillar  has 
sixteen  feet.    Pupa  quiescent  and  complete. 

In  the  second  section,  Crepuscularia,  (jig. 
348,)  the  sphinges  or  hawk-moths,  the  antennae 
are  prismatic,  and  generally  thickest  in  the  mid- 
dle, the  body  large,  and  tapering  towards  its  ex- 
tremity, which  is  often  bearded,  and  the  wings 
are  elongated  and  slightly  deflexed  when  at  rest. 
The  pupa  is  smooth,  and  inclosed  in  a  coccoon, 

*  Westwood,  Transact.  Ent.  Society,  vol.  i. 
p.  169. 

t  Horae  Entomolog.  p.  371. 

\  Mag.  Natur.  Histor.  No.  23. 

6  Ent.  Mag.  vol.  ii.  p.  326. 

|l  Entomol.  Compendium,  1819,  p.  288. 

t  Trans.  Ent.  Society,  vol.  i.  p.  169  et  172. 

**  This  is  also  the  place  assigned  to  it  by  Mr. 
Westwood.  "  Introduction,"  &c.  vol.  ii.  p.  287, 
June  1,  1839. 


INSKCTA. 


867 


Fig.  348. 


Deilephila  elpenor,  the  Elephant  Sphinx, 

or  in  a  cell  of  the  earth.  The  perfect  insects 
fly  very  swiftly,  and  are  mostly  abroad  at 
twilight. 

In  the  third  section,  Pomeridiana,  which 
includes  the  silkworm-moths,  the  body  is  short 
and  thick,  proboscis  in  general  very  short, 
antennae  tapering,  and  much  pectinated  or 
feathered  in  the  males,  and  the  wings,  when  at 
rest,  deflexed  and  horizontal.  The  larva  before 
changing  incloses  itself  in  a  case,  which  in  the 
Bombycida.  is  composed  entirely  of  fine  silk. 

In  the  fourth  section,  Nocturna,  night-moths, 
the  antennas  are  setaceous,  the  proboscis  long 
and  spirally  convoluted,  the  palpi  compressed 
and  terminated  abruptly  by  a  minute  joint,  and 
the  wings,  when  at  rest,  folded  horizontally  upon 
the  abdomen.  It  is  a  larva  of  this  section, 
Agrotis  segeium,  that  of  late  years  has  been 
almost  as  injurious  to  the  agriculturist  by  attack- 
ing the  full-grown  turnip  as  that  of  the  saw- 
fly,  Athalia,  or  the  beetle,  Haltica,  by  attack- 
ing the  plant  in  the  earliest  stages  of  its  growth. 

In  the  fifth  section,  Semidiurna,  the  body  is 
slender,  the  antennas  in  general  setaceous,  the 
proboscis  short,  and  the  wings  broad  and  ex- 
panded horizontally,  as  in  the  Geometrida,  or 
deflexed  and  forming  an  angle  with  the  body  as 
in  the  PyralidtB. 

The  sixth  section,  Vespertina,  is  composed 
of  minute  species,  among  which  are  the  de- 
structive clothes-moths,  Tineida. 

Order  IX.  DIPTERA. 

Wings  two,  membranous,  naked,  and  si- 
tuated anteriorly  to  two  minute  pedunculated 
bodies  (halteres ),  the  analogues  of  the  pos- 
terior wings  in  the  preceding  orders  ;  *  meso- 
thorax  very  large,  and  forming  nearly  the  whole 
of  the  thoracic  region  ;  head  rounded,  distinct 
from  the  thorax  ;  mouth  rostriform  ;  metamor- 
phosis complete  ;  pupa  coarctate. 

Among  the  families  of  this  extensive  order 
are  the  Culicidte,  gnats,  the  Asilidce  (fig.  349) 
and  Tabanidte,  bloodsuckers,  the  (Est  ride, 
gad-flies,  and  Muscida,  common  house-flies. 
In  most  of  the  families  the  larvae  are  active  and 

*  Kiiby  and  Spence,  Introduction,  &c,  vol.  ii. 
p.  354. 


Fig.  349. 


Asilus  crabroniformis  (Samouelle). 

apodal,  or  are  furnished  only  with  abdominal 
feet.  It  is  doubtful  whether  any  of  them  cast 
their  skins  during  their  growth.  In  most  species 
it  becomes  the  outer  covering  of  the  pupa. 

Order  X.  HOMALOPTERA. 

Wings  two,  or  entirely  absent ;  head  sunk 
into  the  anterior  part  of  the  thorax,  or  divided 
from  it  only  by  a  suture  ;  abdomen  flat,  broad, 
and  obtuse ;  anus  notched ;  claws  large,  biden- 
tate  or  tridentate  ;  metamorphosis  complete  : 
pupa  coarctate. 

In  this  remarkable  order,  the  forest-flies  (fig. 
350)  and  ticks,  the  larva  is  nourished,  and  un- 


Fig.  350. 


Hippobosca  equina,  the  Forest-fly  (Samouelle). 

dergoes  its  change  into  the  pupa  state  within  the 
abdomen  of  the  parent,  as  was  first  noticed  by 
Reaumur,  by  whom  they  were  designated  "  spi- 
der-flies." Soon  after  the  pupa  is  deposited,  it 
becomes  greatly  enlarged,  and  equals  in  size  the 
body  of  the  parent.  Reaumur  found  that  its 
outer  envelope  or  case  is  formed  of  the  skin  of 
the  larva,  as  in  the  true  Diptera,  and  he  also 
succeeded  in  detecting  within  it  the  proper 
covering  of  the  nymph.  The  type  of  the  order, 
the  forest-fly  (fig.  350)  is  exceedingly  trouble- 
some to  horses  in  the  summer,  and  abounds  in 
the  New  Forest  in  Hampshire. 

Order  XI.  APHANIPTERA. 

Wings  none  ;  body  oval,  compressed  ;  head 
small,  rounded,  and  compressed ;  eyes  simple, 
orbicular ;  thighs  strong ;  posterior  legs  the 
longest ;  tarsi  five-jointed. 

The  Pulicida,  fleas,  undergo  a  complete 
metamorphosis.  The  larva  is  an  active  elon- 
gated worm,  which  spins  itself  a  case  or  coc- 
coon,  in  which  it  becomes  a  nymph,  and  at 
the  end  of  a  few  days  assumes  the  perfect 
state.  One  species,  Pule.v  penetrans,  is  ex- 
ceedingly troublesome  in  the  West  Indies  by 
introducing  itself  beneath  the  toe-nails  or  under 
the  skin,  where  it  occasions  malignant  ulcers. 
Most  of  the  species  are  of  diminutive  size,  and 
seldom  exceed  a  line  in  length.  Mr.  Kirby, 
"  3  L  2 


868 


INSECTA. 


however,  has  recently  described  one  species, 
P.  Gigus,*  which  is  two  lines  in  length. 

Order  XII.  APTERA. 

Wings  none ;  body  ovate,  flattened  ;  head 
distinct  from  the  thoracic  segments,  which  are 
narrower  than  those  of  the  abdomen  ;  mouth 
either  haustellated  or  mandibulated  ;  metamor- 
phosis incomplete. 

This  order,  which  is  formed  of  the  Pediculi 
of  Linnaeus,  and  is  based  upon  the  entire 
absence  of  the  wings  and  an  incomplete  meta- 
morphosis, affords  a  striking  proof  that  we 
ought  not  in  our  arrangements  to  place  too 
much  dependance  upon  the  presence  or  ab- 
sence of  any  one  particular  set  of  organs,  or 
kind  of  metamorphosis;  else,  as  well  remarked 
by  Burmeister,  we  ought  to  include  among  the 
Aptera  the  female  Blatta  and  the  common 
Cimex,  insects  which  evidently  belong  to 
different  orders.  But  it  may  be  further  ob- 
served that  dissimilarity  in  the  structure  of  one 
particular  kind  of  organs  is  not  alone  sufficient 
to  authorise  the  separation  of  genera  which  in 
other  respects  are  closely  united  ;  otherwise 
the  Nirjnida  (fig.  351)  ought  to  be  separated 


Fig.  351. 


Nirmus,  the  Bird-louse. 

from  the  Pediculida,  although  resembling  them 
in  every  thing  excepting  the  structure  of  the 
mouth,  the  very  part  of  the  animal  upon  which 
the  two  great  divisions  of  insects  in  the  present 
arrangement  is  founded. 

Order  XIII.  HEM  IP  TERA. 
Wings  four,  anterior  ones  partly  leathery, 
partly  membranaceous,  decussating  each  other 
at  the  apex;  posterior  wings  entirely  mem- 
branaceous ;  pro-thorax  and  scutellum  very 
large;  mouth  rostriform,  composed  of  elon- 


Fig.  352. 


Nepa  cinerea,  the  Water-scorpion  (Samouelle). 
*  Fauna  Boreali-Americana,  1837,  p.  318. 


gated  setaj ;  ocelli  three ;  metamorphosis  in- 
complete. 

This  order  is  divided  into  two  sections,  Ter- 
restria  and  Aqucitica. 

The  larva  and  pupa  are  active,  and  most 
species  subsist  upon  the  juices  of  other  ani- 
mals. The  Terrestria  are  distinguished  chiefly 
by  the  length  of  the  antennae,  which  exceeds 
that  of  the  head,  and  by  their  three-jointed 
tarsi.  The  Aquatica  have  the  antennae  in 
general  shorter  than  the  head  (which  in  some 
species  (fig.  352)  is  sunk  into  the  pro-thorax), 
the  eyes  are  large,  the  rostrum  short,  and  the 
tarsi  with  only  two  joints. 

Order  XIV.  HOMOPTERA. 

Wings  four,  anterior  pair  either  entirely 
coriaceous  or  membranaceous,  not  decussating 
each  other ;  pro-thorax  very  short ;  head  large 
and  transverse ;  antennae  shorter  than  the  head 
in  most  genera ;  abdomen  in  some  furnished 
with  a  compound  serrated  ovipositor ;  meta- 
morphosis incomplete. 

This  order  is  considered  by  many  authors  as 
only  a  section  of  the  preceding.  It  is,  how- 
ever, composed  of  several  distinct  families. 
The  types  of  the  order,  the  Cicudiidce  (fig. 
353),  tree-hoppers,  in  possessing  a  serrated 


Fig.  353. 


Cicada  hcematodes  (female ).  (Samouelle). 


ovipositor  seem  to  approach  to  the  Terebrantia, 
while  the  Thripidce,  which  in  the  structure  of 
the  mouth  resemble  mandibulated  insects,  have 
recently  been  formed  into  a  distinct  order,* 
and  have  been  placed  by  Mr.  Westwood  before 
the  Neuroptera.  Perhaps  a  closer  examination 
of  the  remaining  families,  Aphidte  and  Coccidte, 
the  plant-lice,  &c,  might  lead  to  a  similar 
removal. 

In  the  preceding  remarks  we  have  closely 
adhered  to  the  arrangement  proposed  by  Mr. 
Stephens,  but  it  cannot  be  denied  that  much 
remains  to  be  done  before  the  entomologist  will 
be  able  to  form  an  arrangement  so  far  natural 
as  to  be  free  from  serious  objections.  The 
principal  divisions  of  the  last  two  orders,  in 
possessing  ocelli,  in  the  size  of  the  thorax,  the 
connexion  of  the  wings  during  flight  (which 
we  shall  hereafter  show  exists  in  some  of  the 
Cercopiidce,)  and  in  the  serrated  terebral  ovi- 
positor, seem  to  be  more  nearly  connected 
with  the  Hymenoptera  than  with  the  wingless 
and  less  perfectly  developed  Aphaniptera  and 
Aptera. 

From  the  above  remarks  on  the  orders  it  will 

*  Thysanoptera.  Haliday,  in  Entom.  Magazine, 
vol.  iii.  &  iv. 


INSECTA. 


869 


be  seen  that  a  large  majority  of  insects  have  four 
states  of  existence, — the  egg,  the  larva,  the 
pupa,  and  the  imago  or  perfect  state.  Until 
very  lately,  it  was  supposed  that  this  peculiarity 
of  existing  at  different  periods  under  such 
different  forms  belonged  only  to  this  class  of 
the  Invertebrata,  but  recent  observation,*  as 
shown  in  the  article  Cirrhopoda,  &c.,f  has 
made  it  appear  that  there  are  other  classes 
also  which  undergo  metamorphoses,  although 
in  no  instances  do  the  animals  continue  so  long 
in  their  preparatory  states,  nor  undergo  such 
remarkable  changes  of  form  in  passing  from 
one  state  to  another,  as  insects. 

The  egg. — In  the  egg,  or  earliest  stage  of 
extra-uterine  existence,  the  insect  continues  for 
a  longer  or  shorter  time  according  to  external 
circumstances.  We  have  at  present  only  to 
notice  the  external  form,  markings,  and  colour 
of  the  egg,  which  vary  as  greatly  in  the  dif- 
ferent species  as  the  locality  in  which  it  is 
placed  by  the  parent.  The  greatest  variety  of 
these  occurs  among  the  Lepidopterous  insects. 
In  some,  as  in  the  butterfly,  Pontia  brassica, 
the  egg  is  of  an  obtuse  conical  figure,  like  a 
Florence  flask,  and  is  beautifully  ribbed  and 
beaded  on  its  exterior  surface  ;  in  others,  as  in 
one  of  the  night-moths,  Acronycta  Psi,  it  is 
ribbed,  and  is  flattened  like  a  lens; J  in  the 
small  but  beautiful  butterfly,  Tliecla  betula, 
it  is  shaped  like  a  turban  ;§  in  Clisiocampa 
neustria,  which  glues  its  eggs  together  like  a 
ring  around  the  small  branches  of  fruit-trees, 
it  is  cylindrical,  and  flattened  at  both  ends, 
and  in  the  puss-moth,  Cerura  vinulu,  its  form 
is  compressed  and  lenticular.  Among  the  Neu- 
roptera,  Hemiptera,  and  Diptera  there  are  other 
forms  equally  curious.  The  lace-winged  fly, 
Chrysopa  perla,  suspends  its  egg  in  the  air  upon 
a  long  pedicle  ;||  the  egg  of  the  water-scorpion, 
Nepa  cinerea  (fig.  3.52),  is  encircled  at  one 
extremity  by  a  coronet  of  rays  or  processes,!! 
while  in  one  of  the  dung-flies  the  egg  has  two 
projecting  appendages  which  have  somewhat 
the  appearance  of  ears.  The  color  and  mark- 
ings of  the  egg  are  not  so  various  as  its  form. 
In  the  common  green  grasshopper,  Acrida 
viridissima,  it  is  green,  like  the  seeds  of  some 
plants.  In  Pedicia  rivosa  and  Tipula  oleracea 
it  is  perfectly  black,  and  in  other  instances,  as 
in  Odonestis  potatoria,  it  is  beautifully  en- 
circled with  bands  of  white  and  green,  or  is 
speckled  with  darker  spots,  like  the  esgs 
of  birds,  as  in  Lassiocampa  quercus.  The 
prevailing  colours,  however,  are  yellow,  as  in 
the  cylindrical  eggs  of  the  oil-beetles,  the  Mcloe 
and  Proscarabai;  or  white  as  in  the  flesh-flies, 
Musca  vomitoriu  and  duwestica  ;  or  perfectly 
translucent,  as  in  the  saw-fly  of  the  turnip, 
Alitalia  centifolie.  The  external  markings 
and  sculpture  on  the  egg  are  not  less  remark- 
able than  its  general  form  and  colour.  Some- 

*  Phil.  Trans,  part  ii,  1835. 
,  f  Vol.  i.  p.  692. 
t  Sepp. 

§  Id.  quoted  by  Burmeister,  Manual  of  Ento- 
mology (Trans.),  p.  633. 

U Reaumur,  Kirby  and  Spcnce,  vol.  iii.  p.  95. 
I  Swammcrdam  Bib.  Nat.  t.  iii.  figs.  7  and  8. 


times  the  egg,  as  above  stated,  is  ribbed  and 
beaded,  sometimes  excavated  over  its  whole 
surface  into  regular  cells  like  a  honey-comb, 
at  others  it  is  imbricated  like  the  tiling  of  a 
house,  but  in  the  greater  number  of  instances 
it  is  smooth  as  in  other  animals. 

These  peculiarities  of  form  and  color  appear 
in  many  instances  to  have  relation  to  the  cir- 
cumstances under  which  the  egg  is  deposited 
by  the  parent,  to  its  preservation,  or  to  the 
locality  in  which  it  is  placed.  The  egg  of 
Scatophaga  stercoruria,  Kirby,  is  only  par- 
tially inserted  into  recent  cow-dung,*  with  its 
auricular  processes,  through  which  it  is  sup- 
posed to  respire,  exposed  to  the  influence  of  light 
and  air;  that  of  Chrysopa  perla,  K.,  the  lace- 
winged  fly,  is  attached  by  its  pedicle  in  the 
midst  of  crowds  of  Aphides,  upon  which  the 
young  larva  is  to  subsist  ;f  while  the  coro- 
netted  eggs  of  Nepa  (Jig.  352)  are  inserted  into 
the  stems  of  water-plants,  with  their  processes 
only  exposed,^  probably  for  the  purposes  of 
respiration,  until  the  enclosed  germs  are  stimu- 
lated into  active  existence  by  the  vivifying 
influence  of  light  and  air,  without  which 
perhaps  they  would  perish.  This  indeed 
happens  with  the  eggs  of  the  great  water- 
beetle,  Hydrous  piceus  (Jig.  330)  which,  ac- 
cording to  Lyonet,  are  deposited  in  a  little  nest 
that  floats  upon  the  surface,  and  from  which 
the  larva;  escape  into  the  water  immediately 
they  are  developed.  We  have  found  that  if 
the  eggs  of  this  insect  be  allowed  to  fall  to  the 
bottom  of  a  vessel  of  water,  and  remain  there 
for  some  days,  organisation  proceeds  in  them 
for  a  day  or  two,  after  which  they  perish.  For 
a  similar  purpose  the  eggs  of  Athalia  centi- 
j'olia  (Jig.  355),  which  require  a  high  atmos- 
pheric temperature  for  their  speedy  development, 
are  inserted  into  little  spaces  between  the  cuticle 
and  parenchymatous  tissue  of  the  leaf  of  the 
turnip.  In  each  of  these  instances  the  object 
to  be  insured  is  the  safety  of  the  egg  itself ; 
either  its  preservation  from  external  injury,  or 
its  full  exposure  to  atmospheric  influence  to 
accelerate  its  development.  It  may  be  re- 
marked as  a  general  rule,  that  those  eggs  from 
which  the  larva;  are  most  rapidly  developed 
are  those  which  require  the  highest  tempera- 
ture and  fullest  exposure  to  the  atmosphere. 
These  are  the  external  circumstances  which 
greatly  influence  the  development  of  the  germ 
into  the  state  of  larva. 

The  larva.— Immediately  the  insect  is  liber- 
ated from  the  external  coverings  of  the  egg  it  is 
called  a  larva.  It  is  so  designated  from  its 
then  being  as  it  were  under  a  mask  or  in  dis- 
guise, and  unable  to  fulfil  one  of  the  principal 
objects  of  its  existence,  the  continuation  of  its 
kind.  In  some  species,  as  anions  the  Aptera, 
it  has  at  this  period  the  form  of  the  parent, 
from  which  it  differs  in  nothing  externally  but 
size,  being  always  very  much  smaller.  Instances 
of  this  kind  occur  in  the  Pediculi  and  Nirmi 
(fig.  351).  In  other  species,  examples  of 
which  are  seen  in  the  Cimkes,  Btatta  (fig.  343)» 

*  Kirby  and  Spencc,  vol.  iii.  p. 97. 

+  Reaumur,  torn.  iv.  p.  376. 

j  Kirby  and  Spcnce,  vol.  iii.  p.  95. 


870 


INSECTA. 


Forficula,  and  Cicada  (fig.  353),  the  insect 
is  very  much  smaller,  but  has  the  general  form 
of  the  parent,  without  any  rudiments  of  wings 
or  elytra.  Another  description  of  larva  is  that 
in  which  the  insect  comes  from  the  egg  either 
as  a  fat  sluggish  grub,  or  as  an  active  and  vora- 
cious one,  with  an  elongated  body  very 
different  in  form  from  that  of  the  parent,  and  is 
furnished  with  but  six  legs,  which  are  attached 
to  the  anterior  part  of  the  body,  in  addition  in 
some  instances  to  two  processes  employed  as 
legs  at  its  posterior  extremity.  Examples  of 
the  last  of  these  occur  in  the  voracious  water- 
beetles,  Dyticida,  in  the  Carabidcc  or  ground- 
beetles  (fig.  354)  and  many  others  ;  and  of  the 


Fig.  354. 


Larva  of  Calosoma  Sycophanta  (  Burmeister). 

first,  in  the  Chaffer-beetles  Melolontha,  and 
stag  and  dung-beetles,  Eucanida  and  Geotru- 
pidm  (fig.  332).  Other  kinds  of  larvae,  to 
which  the  term  is  more  strictly  applicable,  are 
known  to  every  one,  as  the  caterpillars  of 
butterflies  and  moths.  These  and  the  pseudo- 
caterpillars,  the  larvae  of  the  saw-flies,  Ten- 
thredinida,  (fig.  355,  a),  are  active  and  have 


Fig.  355. 

B  A 


A  ,  larva,  and  B,  perfect  state  of  Athalia  centifoliee, 
the  saw-fly  of  the  turnip,   ( Newport,  Prize  Essay.) 

elongated  bodies  furnished,  in  addition  to  the 
six  legs  at  the  anterior  part,  with  many  others 
along  the  posterior.  They  undergo  a  complete 
metamorphosis,  both  of  external  and  internal 
conformation  in  passing  from  the  larva  to  the 
perfect  condition.  Besides  these  there  are,  as 
in  the  instance  of  hornets  (figs.  356  and  357) 
and  bees,  larvae  which  are  entirely  destitute  of 
organs  of  locomotion,  and  exist  simply  as  elon- 
gated maggots ;  and  others,  as  some  of  the 
flesh-flies,  Musca,  and  the  tailed  maggots  that 
inhabit  the  most  noisome  puddles,  Eristalis 
teuax,  which  are  entirely  destitute  of  the  true  or 
anterior  legs,  and  have  only  those  which  are 
attached  to  the  abdomen. 

These  kinds  of  larvae  were  formerly  referred 
by  Fabricius,  under  special  designations,  to 


different  kinds  of  metamorphoses,  which  those 
designations  were  supposed  to  indicate;  but,  as 
remarked  by  Burmeister,*  neither  were  the 
terms  employed  in  strict  accordance  with  the 
conditions  of  the  larvae  themselves,  nor  always 
indicatory  of  the  metamorphoses  they  were 
about  to  undergo.  We  fully  agree,  therefore, 
in  the  opinion  expressed  by  Burmeister,  that 
the  different  kinds  of  larvae  are  referable  to 
only  two  kinds  of  metamorphoses;  the  one  a 
metamorphosis  incompletu,  which  consists  sim- 
ply in  the  insect  shedding  its  skin  and 
increasing  in  size,  and  in  some  cases  acquiring 
new  organs,  but  in  all  stages  of  its  existence 
continuing  active,  and  having  the  form  of  the 
parent,  as  in  the  instances  above  noticed ; 
and  the  other  a  metamorphosis  cornpleta,  in- 
cluding all  insects  which  in  the  larva  state  have 
a  form  different  from  the  parent,  and  undergo 
a  complete  change,  both  of  external  and  inter- 
nal conformation,  before  they  arrive  at  the  per- 
fect state. 

But  whatever  be  the  form  or  changes  of  the 
insect,  the  larva  state  may  be  looked  upon  as 
its  most  voracious  period  of  life.  In  many 
species  it  is  also  its  longest  period.  Those 
which  do  not  hybernate  in  the  perfect  state 
exist  but  for  a  very  short  time  as  larvae ;  while 
those  which  continue  for  a  long  period  in  the 
larva  state,  as  the  Eucanida  and  Melolonthidse, 
some  of  which  are  said  to  continue  for  four 
years,  pass  but  a  little  while  in  the  perfect. 
But  these  periods  are  not  always  equally  long 
in  different  species  of  the  same  families.  Thus 
among  the  Apidxe,  the  Bombus  terreslris,  or 
common  humble-bee,  exists  but  for  a  short 
period  in  the  larva,  but  a  long  one  in  the  per- 
fect state  ;  while  in  a  closely  allied  genus  An- 
t/wphora  retusa,  one  of  the  solitary  bees,  that 
form  separate  nidi  in  vertical  sections  of  dry 
banks  exposed  to  the  sun,  the  insect  often  con- 
tinues through  the  whole  winter  in  the  larva 
state,  and  only  exists  for  a  few  weeks  of  the 
following  summer  in  the  perfect.  On  the 
other  hand  the  numerous  species  of  Muscidce 
exist  but  a  short  time  as  larva?,  or  maggots,  but 
a  very  long  time  as  active  flies. 

External  unatomy  of  the  larva. — The  body 
of  a  larva  is  in  general  composed  of  thirteen 
distinct  segments,  or  divisions  ;  the  first  consti- 
tutes the  head,  with  the  organs  of  manducation, 
the  second,  third,  and  fourth,  and,  as  we  shall 
hereafter  see,  in  part  also  the  fifth,  together 
form  the  thorax  of  the  future  Imago,  while 
the  remaining  ones  form  the  third  division  of 
the  body,  the  abdomen.  In  most  insects  in  the 
larva  state,  the  whole  of  these  segments  from 
the  second  to  the  thirteenth  are  equally  deve- 
loped, and  differ  but  little  from  each  other  in 
their  general  appearance.  The  second,  third, 
and  fourth  segments  have  each  a  pair  of  short 
scaly  feet,  the  rudiments  of  the  future  limbs, 
and  the  segments  of  the  abdomen  are  often 
furnished  with  soft  membranaceous  ones,  which 
disappear  entirely  when  the  larva  undergoes 
its  metamorphosis.  On  each  side  of  the  body 
there  are  in  general  nine  oval  apertures,  the 

*  Manual,  Trans,  p.  34. 


INSECTA. 


871 


spiracultc,  or  breathing  holes.  These  are  situ- 
ated in  the  true  larva,  or  caterpillar,  in  the 
second,  fifth,  sixth,  and  following  segments  to 
the  twelfth.  This  is  the  general  structure  of 
the  larva,  but  there  are  modifications  of  it  in 
every  particular.  Thus,  in  the  larva  of  those 
Ht/menopterous  insects  which  are  entirely  desti- 
tute of  feet,  there  are  fourteen  distinct  segments 
in  the  body,  besides  an  anal  tubercle,  and  ten 
spiraculae  on  each  side  (Jig.  356).    These  are 


Fig.  356.  Fig.  357. 


Lateral  view.  Inferior  view. 

Larva  of  Vespa  crabro,  magnified. 

situated  in  the  second,  third,  fourth,  and  remain- 
ing segments  to  the  twelfth,  so  that  in  these  in- 
sects the  thoracic  portion  of  the  body  contains 
an  additional  spiracle,  while  the  abdomen  has 
one  additional  segment.  This  fact  is  particularly 
interesting  from  the  circumstance  of  its  appa- 
rently disturbing  the  opinions  hitherto  advocated 
by  naturalists  respecting  the  normal  number  of 
segments,  which  has  been  thought  to  be  con- 
stantly thirteen  in  this  class  of  invertebrata,  while 
it  derivesa  greater  importance  from  theadditional 
segment  belonging  to  the  abdomen,  as  we  shall 
hereafter  prove.  This  additional  number  of 
segments,  as  constantly  occurring  in  apodal 
Hymenoptera,  was  first  pointed  out  by  Mr. 
Westwood,*  and  has  been  observed  by  ourselves 
in  every  instance  in  the  larvae  of  Vespa  Crabro, 
(jig.  356.)  Bomb  us  terrcstris,  Anthophora 
return,  Ichneumon  Atropos,  and  other  species. 
In  the  common  maggots  or  larvae  of  the  flesh- 
flies,  Muscidte,  the  body  is  elongated,  and 
tapering  at  its  anterior  extremity,  and  con- 
sists of  fourteen  segments. f  In  the  larva  of  a 
species  of  Musca  which  infests  bacon  and  other 
dried  provisions,  and  in  that  of  the  common 
flesh-fly,  Musca  vomitoria,  we  have  distinctly 

*  Trans.  Ent.  Soc.  vol.  ii.  p.  124. 

t  Fifteen,  if  wc  include  the  anterior  portion  of 
the  third  segment,  which  appears  like  a  distinct 
part.  Since  these  observations  have  been  in  print 
the  XII.  and  XIII.  Parts  of  Mr.  Wcstwood's  "  In- 
troduction "  have  been  published,  and  it  is  grati- 
fying to  observe  that  he  has  found  fifteen  segments, 
including  the  head,  in  th<i  larvu  of  OdynerilS,  Col- 
letes,  and  Anthidium. 


noticed  fourteen  (fig.  358).    The  first  four  of 


Fig.  358. 


A,  Apodal  larva  of  Sfusca ;  B,  headof  do.:,a,  mandi- 
bular hooks  ;  b,  the  anterior  bronchia;  c,  the  labium  ; 
C,  organs  of  respiration;  D,  a  portion  of  the  dorsal  vessel. 

these  appear  to  constitute  the  head  of  the  larva, 
since  in  them  are  contained  the  palpi  and  oral 
apparatus,  besides  two  remarkable  orange- 
coloured  organs,  which  project  from  the  sides 
of  the  fourth  segment,  and  on  a  cursory  view 
appear  to  be  the  organs  of  vision,  but  are  in 
reality  the  branchiae  of  the  future  pro-thorax 
(B  /;).  In  the  larva  of  the  sheep-bot,  (Estrus 
ovis,  which  resides  for  many  months  in  the 
frontal  sinuses  and  roots  of  the  horns  of  that 
animal,  there  are  thirteen  segments,  but  the 
terminal  one  is  very  indistinct,  while  the  an- 
terior one,  which  is  exceedingly  minute,  is 
proved  to  form  a  large  proportion  of  the  head, 
by  its  containing  the  oral  apparatus-,  and  by 
the  existence  in  it,  at  its  anterior  part,  of  two 
very  distinct  eyes.  These  larvae  respire  by 
means  of  two  sets  of  branchiated  organs, 
(fig.  358,  c)  situated  at  the  posterior  part 
of  the  body,  and  not  by  lateral  spiracles. 
The  apparently  anomalous  condition  of  the 
head  in  these  insects,  like  the  additional 
segment  in  Hymenoptera,  is  a  circumstance 
of  much  interest,  but  is  not  without  its 
parallel  in  perfect  individuals  of  other  classes, 
as  in  Myriapoda,  in  which  the  head  is  most 
distinctly  composed  of  at  least  three  seg- 
ments. We  must  not  conclude,  however,  with 
Dr.  Ratzeburg,  as  noticed  by  Mr.  West- 
wood,*  that  in  Hymenoptera  the  head  of  the 
Imago  corresponds  to  the  first  two  segments 
of  the  larva,  because  at  the  latter  period  of 
the  larva  state,  just  before  the  insect  becomes 

*  Trans.  Ent.  Soc.  vol.  ii.  p.  125. 


872 


INSECTA. 


a  nymph,  or  pupa,  the  head  is  found  to  occupy 
the  anterior  part  of  the  second  segment.  The 
true  head  of  the  hymenopterous  larva,  before  its 
changes  have  commenced,  is  in  reality  the 
first  segment ;  since,  as  remarked  by  Mr. 
Westwood,  it  has  not  only  the  usual  conforma- 
tion of  the  head,  but  contains  also  the  rudi- 
ments of  all  the  manducatory  organs,  and  the 
antenna;.  In  addition  to  this,  we  may  state 
that  before  the  larva  has  discontinued  to  feed, 
and  has  begun  to  prepare  itself  for  transforma- 
tion, we  have  invariably  found  on  dissection, 
that  the  first  cerebral  mass,  the  supra-cesopha- 
geal  ganglion  or  brain  is  situated  in  the  superior 
part  of  the  first  segment,  and  the  first  sub- 
cesophageal  ganglion  in  the  posterior  part  of  the 
inferior  surface;  so  that  it  is  not  until  after 
the  changes  into  the  nymph  state  have  com- 
menced, beneath  the  skin  of  the  larva,  that  the 
head  becomes  so  greatly  enlarged  as  to  en- 
croach upon  the  second  segment. 

Of  the  head.  The  head  of  a  larva,  excepting 
in  Dipterous  insects  as  above  noticed,  is 
usually  of  a  rounded  or  oval  figure,  and  of  a 
harder  texture  than  other  parts  of  the  body. 
At  its  inferior  surface  are  situated  the  organs  of 
manducation,  and  at  its  lateral  and  anterior  the 
rudiments  of  the  eyes  and  antenna;.  In  all 
true  larvae  it  is  divided  longitudinally  into  two 
halves,  by  a  suture  which  extends  from  the 
vertex  or  epicranium  to  thtj  face,  the  front  of 
which  is  formed  by  a  convex  plate,  the  clypeus, 
or  shield  (fig.  359,  b).    This  is  generally  of  a 

Fig.  359. 


Head  of  larva  of  Athalia  centifoliee. 
a,  the  epicranium  ;  b,  the  clypeus  ;  c,  labrum  ;  d,  the 
mandibles  ;  e,  maxillee  and  palpi ;  f,  ,the  labium  and 
labial  palpi.    (  Newport,  Prize  Essay.) 

semicircular,  or  a  quadrangular  form,  but  varies 
considerably  in  different  species.  Immediately 
beneath  this  plate  is  situated  another,  the 
labrum  or  upper  lip  (c).  This  also  is  of  an 
elongated,  quadrangular,  and  sometimes  heart- 
shaped  form,  and  constitutes  the  anterior 
boundary  of  the  mouth.  Beneath  this  plate  are 
a  pair  of  strong  horny  jaws,  mandibular  (d), 
which  are  in  general  thick,  curved,  and  strongly 
indented  or  toothed,  and  are  placed  one  on  each 
side  of  the  head.  Beneath  these  are  a  pair  of 
lesser  jaws,  maxilla  (e),  placed  in  a  similar 
manner,  and  with  the  mandibles  form  the 
lateral  boundaries  of  the  mouth.  The  maxillae 
are  soft,  membranaceous  and  adapted  for 
holding,  rather  than  for  comminuting  the  food 
like  the  mandibles.  They  are  in  general  also 
furnished,  as  in  ihe  larva  of  Athalia,  with  two 


other  jointed  organs,  palpi  or  feelers  which  are 
employed  by  the  insect  entirely  as  tactors. 
Behind  these  parts  is  situated  a  second  trans- 
verse plate,  the  labium  {J'),  or  inferior  lip, 
which  bounds  the  posterior  part  of  the  mouth. 
This  also,  like  the  maxilla,  is  furnished  with  a 
pair  of  jointed  palpi.  The  motions  of  the  man- 
dibles and  maxillae  differ  from  those  of  the 
jaws  in  vertebrated  animals,  being  always  from 
side  to  side,  and  meeting,  or  passing  across 
each  other  like  the  blades  of  a  pair  of  scissors. 
Besides  these  parts,  there  is  in  many  larvae  a 
projecting  papilla  situated  within  the  mouth 
upon  the  soft  membrane  of  the  labium.  This 
is  conical  and  jointed,  and  is  called  by  Messrs. 
Kirby  and  Spence  the  spinneret.  It  is  the 
common  excretory  duct  of  the  glands  which 
secrete  the  materials  with  which  the  insect  spins 
its  coccoon,  previously  to  undergoing  its  trans- 
formations. In  all  larvae  the  antenna  (g)  are 
but  slightly  developed.  They  are  situated  a 
little  above  the  base  of  the  mandibles,  on  each 
side  of  the  clypeus,  and  are  of  a  conical  form, 
jointed,  and  usually  terminating  in  a  point. 
In  some  species  they  are  three,  but  rarely 
more  than  five-jointed.  The  eyes  in  all  larvae 
are  single,  or  sessile,  and  not  compound,  or 
aggregated  together,  as  in  perfect  insects.  In 
the  pseudo-caterpillars,  Tenthredinida,  as  in 
Athalia  centijblue,  there  is  only  one  large  stem- 
ma  on  each  side  of  the  head  (A),  situated  above 
the  antennae ;  but  in  the  true  caterpillars,  Lepi- 
duptera,  as  in  the  Sphinx  ligustri,  there  are 
always  six  very  minute  ones,  placed  at  a  little 
distance  from  each  other,  in  the  form  of  an 
arc  near  the  base  of  the  mandibles  and  antennae, 
at  the  lateral  part  of  the  head.  In  the  apodal 
hymenopterous  larvae  which  constantly  reside  in 
the  dark,  the  oral  apparatus  is  developed,  but 
the  eyes  are  in  general  entirely  absent. 

The  form  of  the  oral  apparatus  in  the 
maggots,  or  larva?  of  the  Dipterous  insects, 
is  entirely  different  from  that  of  the  insects  we 
have  just  described.  In  the  larva  of  (Estrus 
ovis  instead  of  mandibles  and  maxillae  crossing 
each  other  transversely,  the  mouth  is  formed  by 
two  fissures,  the  one  anterior  and  longitudinal, 
and  the  other  posterior  and  transverse,  the  two 
meeting  each  other  in  the  form  of  the  letter  T 
inverted  thus  j,  (fig.  360).  In  the  anterior 
fissure  (c)  are  situated  two  longitudinal  power- 
ful hooks,  the"  mandibles  (d)  directed  forwards 
and  downwards,  and  employed  by  the  insect 
both  as  organs  of  progression  and  nutrition. 
At  the  base  of  these  in  the  transverse  fissure  (e), 
are  two  other  hooks,  maxillae,  of  a  similar  des- 
cription, directed  both  to  the  median  line,  but 
jointed  like  the  mandibles  in  Myriapoda,  and 
crossing  each  other  like  the  mandibles  of  the 
true  larva.  The  hooks  thus  include  between 
them  the  cavity  of  the  mouth,  in  this  manner 
adapted  both  for  wounding  and  tearing  as  well 
as  suction,  and  it  is  curious  to  observe  that  we 
have  here  in  the  larva  of  a  true  insect  an  ap- 
proach to  the  vermiform  type  of  the  permanent 
condition  of  the  oral  apparatus  of  the  leech.  In 
the  maggot  of  the  larder-flies  and  flesh-flies 
above  ailuded  to,  the  mouth  is  formed  some- 
what differently.    Behind  the  transverse  hooks 


INSECTA. 


873 


the  mouth  is  bounded  by  a  membranaceous 
labium,  while  at  its  anterior  part  it  is  furnished 
with  a  proboscidal  lip  ( fig.  358,  B  c),  divided 
into  four  very  minute  palpiform  organs.  There 
are  also  two  processes  situated  one  on  each 
side  of  the  mouth  in  the  second  segment.  At 
the  base  of  the  fourth  segment  are  the  two  pro- 
jecting orange-coloured  organs  of  a  semicircular 
form,  divided  into  what  appear  like  single 
pedunculated  eyes,  but  which  are  in  reality 
external  branchiae,  and  correspond  to  the  spira- 
cles of  the  pro-thorax  of  the  perfect  insect  (//). 
In  the  CEstrus  ovis  (fig.  360)  the  two  sides  of 

Fig.  360. 


6 


Head  of  larva  of  QZstrus  ovis. 
2,  3,  4,  segment ;  a,  optic  nerve ;  b,  epicranium  ;  c, 
labium ;  d,  mandibles  ;  e,  maxillce. 

the  fissure  that  forms  the  anterior  part  of  the 
mouth  are  developed  into  very  distinct  organs 
of  vision  (A),  in  which  may  be  traced  the  nerves 
of  two  separate  but  nearly  approximated  eyes. 
The  existence  of  distinct  eyes  in  this  larva  is 
the  more  remarkable,  from  the  circumstance  that 
the  larva  resides  in  the  frontal  sinus  of  the  skull 
of  the  sheep,  where  we  sought  for,  and  found 
the  identical  specimens  upon  which  our  obser- 
vations have  been  made. 

Organs  of  locomotion.  We  stated  above  that 
the  true  organs  of  locomotion  are  six  in  num- 
ber, both  in  the  larva  and  perfect  state,  and 
that  they  are  always  attached  to  the  second, 
third,  and  fourth  segments  of  the  body.  They 
are  distinguished  from  the  false,  or  abdominal 
legs  by  their  possessing  distinct  articulations 
or  joints,  by  the  strength  and  hardness  of  their 
texture,  ;md  by  their  general  pointed  form.  In 
Coleopterous  larvae  they  are  of  considerable 


length,  and  the  parts  of  which  they  are 
composed  are  readily  distinguished.  These 


Fig.  362.  Fig.  361. 


Fig.  361,  Thoracic  leg  of  larva  of  Cossus  ligniperda 
(Lyonet). 

o,  Coxa ;  b,  femur  ;  c,  tibia  ;  d,  tarsus  ;f,  unguis. 
Fig.  362.  Abdominal  leg. 


are  (figs.  361,  364  ***),  as  in  the  perfect 
insect,  the  claw  {J'),  the  tarsus  (cl),  the  tibia 
(c),  the  femur  (6),  and  coxa,  or  hip  (a).  In  all 
terrestrial  larvae  the  legs  are  attached  to  the 
inferior  parts  of  the  segments ;  but  in  one 
remarkable  genus  of  water-beetles  the  great 
Hydrous  piceus,  they  were  supposed  by  Frisch 
to  be  attached  so  much  nearer  to  the  dorsal 
than  the  sternal  surface  as  to  have  the  appear- 
ance of  being  actually  placed  on  the  back.  But 
this  is  erroneous,  the  mistake  having  arisen 
from  the  peculiar  formation  of  the  head,  which 
is  flat  on  its  upper,  but  convex  on  its  under  sur- 
face. The  whole  of  these  thoracic  legs,  in  all 
larvae  which  possess  them,  are  nearly  equally 
developed,  and  do  not  present  any  marked 
difference  of  form  or  size,  as  is  often  sub- 
sequently found  in  the  perfect  insects.  In  the 
larvae  of  Lepidoptera  they  are  exceedingly 
short  and  pointed,  and  in  many  Hymenoptera 
and  Diptera  are  entirely  absent.  The  false  or 
abdominal  legs  are  totally  different  in  appear- 
ance and  structure  from  the  true  or  thoracic  ones. 
Although  varying  in  number  in  different  species, 
they  are  universally  present  in  the  Lepidoptera 
(fig.  364,  ttt)  an<l  m  many  Hymenoptera  and 
Diptera.  In  some  instances,  as  in  many  of 
the  Geometridte,  there  is  only  a  single  pair  at 
the  anal  extremity  of  the  body  ;  while  in  others, 
as  in  some  of  the  Tenthredinida,  there  are  as 
many  as  eight  pairs.  In  every  instance  they 
are  soft  and  membranaceous,  without  distinct 
joints  or  articulations.  In  some  of  the  Lepi- 
doptera their  structure  is  exceedingly  curious, 
and  has  been  beautifully  illustrated  by  Lyonet 
(fig-  362),  in  his  anatomy  of  the  larva  of 
Cossus  ligniperda.  In  that  insect  their  shape 
resembles  an  inverted  cone,  with  its  apex  trun- 
cated to  form  a  flat  sole,  or  foot,  upon  which 
the  caterpillar  walks.  The  sole  in  its  middle 
can  be  rendered  concave  at  the  will  of  the 
animal,  while  around  its  margin  are  several 
rows  of  minute  hooks,  directed  outwards,  and 
when  the  sole  of  the  foot  is  pressed  firmly  upon 


874 


INSECTA. 


any  surface  in  walking  these  hooks  attach 
themselves,  and  are .  released  again  when  the 
sole  of  the  foot  is  contracted,  previously  to  the 
caterpillar's  raising  it  to  make  another  step 
forwards.  In  the  Sphingida  the  abdominal 
feet  are  formed  of  two  parts,  the  external  one, 
broad,  semicircular,  and  edged  with  minute 
hooks,  directed  inwards  like  a  claw,  and  the 
internal  one  smaller,  with  its  hooks  directed 
outwards,  so  that  two  parts  of  the  foot  are 
opposed  to  each  other,  and  grasp  the  surface 
upon  which  they  are  walking  like  the  foot  of  a 
bird.  It  is  with  these  that  the  Sphinx  at- 
taches itself  so  firmly  to  the  stems  and  branches 
of  plants,  that  it  is  often  almost  impossible  to 
remove  it  without  injury.  In  the  Sphinx  there 
are  four  pairs  of  these  legs,  attached  to  the 
seventh,  eighth,  ninth,  and  tenth  segments, 
besides  one  pair  at  the  thirteenth,  or  anal  ex- 
tremity. In  some  Dipterous  larva  the  abdomi- 
nal legs  are  the  only  organs  of  locomotion — as 
in  the  rat-tailed  larva  of  Eristalis  tenax. 

In  every  instance  these  abdominal  legs  are 
only  processes  of  the  exterior  covering  of  the 
insect,  furnished  externally  with  peculiar  deve- 
lopments of  the  cuticle,  in  the  form  of  hardened 
spines  or  hooks  like  the  claws  and  nails  of  ver- 
tebrated  animals,  and  internally  with  a  greater 
development  of  certain  portions  of  the  muscles 
of  the  abdomen.  We  have  full  proof  of  this 
in  those  numerous  apodal  larva  which  are 
capable  of  locomotion,  as  in  most  of  the 
Muscida,  the  common  maggots.  In  all  these, 
in  which  both  the  true  and  false  legs  are  entirely 
absent,  the  whole  external  surface  of  the  body 
is  modified  for  this  purpose.  In  the  maggot 
of  the  flesh-fly  the  whole  anterior  part  of  every 
segment  is  surrounded  and  beset  with  numbers 
of  very  minute  hooks,  with  their  apices  directed 
backwards.  With  these  the  larva  attaches 
itself  to  the  surface  over  which  it  moves,  and 
carries  itself  along  by  the  alternate  contraction 
and  relaxation  of  the  longitudinal  muscles  of 
its  body.  A  beautiful  adaptation  of  these 
dermal  hooks  to  the  peculiar  habits  of  the 
individual  is  observed  on  comparing  their  form 
and  position  on  the  bodies  of  the  larva;  of  two 
very  distinct  species  of  (Est?-us,  the  one  (Est?-us 
ovis,  parasitic  in  the  head  of  the  sheep,  the 
other  beneath  the  skin  on  the  backs  of  oxen, 
(Eslrus  bovis.  In  the  first  of  these  larva,  which 
moves  about  freely  in  its  habitation,  the  hooks 
(Jig-  360)  are  all  directed  backwards  around 
the  posterior  margin  of  each  segment,  a  direc- 
tion rendered  necessary  for  their  employment 
as  organs  of  locomotion  ;  but  in  the  latter  insect, 
which  is  confined  to  one  spot  for  many  months, 
in  the  tumour  occasioned  by  it  on  the  back  of 
the  ox  in  the  cellular  tissue  beneath  the  skin, 
the  hooks  are  not  required  as  organs  of  pro- 
gression, but  yet  are  rendered  necessary  for  the 
purpose  of  retaining  the  larva  in  its  nidus  un- 
affected by  the  varied  muscular  movements  of 
the  parts  around  it.  To  accomplish  this  object 
each  segment  of  the  larva  is  provided  with  two 
sets  of  hooks.  One  of  these  is  arranged  around 
the  anterior  part  of  the  segments,  and  consists 
of  very  numerous  minute  sharp- pointed  spines, 
directed  forwards,  while  the  other  is  composed 


of  strong  flattened  scales  with  curved  points, 
very  much  larger  but  less  numerous  than  the 
preceding.  These  are  disposed  around  the 
posterior  part  of  the  segments,  and  have  their 
points  directed  backwards.  The  effect  of  the 
spines  thus  placed  in  opposite  directions  evi- 
dently is  that  of  retaining  the  larva  in  exactly 
the  same  position  among  the  cellular  tissue  in 
the  back  of  the  animal,  while  the  greater 
strength  of  the  posterior  spines  enables  it  at 
will  to  penetrate  deeper  beneath  the  skin  of  its 
victim. 

We  have  thus  seen  that  in  apodal  larva  en- 
dowed with  powers  of  locomotion  the  place  of 
the  true  organs  of  progression  is  supplied  by 
peculiar  developrrients  of  the  cuticular  covering 
of  the  body,  analogous  to  the  scales  on  the 
bodies  of  Ophidian  Reptiles,  and  these  are 
employed  by  the  larva  in  all  their  progressive 
movements  in  the  same  manner  as  the  scales 
on  the  body  of  the  snake.  But  in  those  apodal 
larva  which  remain  in  the  same  locality  until 
they  have  passed  through  all  their  changes,  as 
the  larva  of  the  bee  and  wasp,  these  develop- 
ments of  the  quticular  surface  do  not  exist,  but 
the  body  is  perfectly  smooth. 

It  is  not  always,  however,  that  the  spines 
on  the  bodies  of  larva  are  employed  as  organs 
of  locomotion  since  they  exist  on  many  larva 
which  possess' both  true  and  false  feet,  and  are 
then  either  merely  ornamental  appendages  or  a 
means  of  defence.  But  whatever  be  their  use 
in  the  economy  of  the  larva,  they  are  only 
developments  of  its  external  covering,  and 
generally  disappear  when  the  insect  undergoes 
its  change  into  the  pupa  state,  being  thrown  off 
with  the  skin. 

Growth  and  changes  of  the  larva. — The  life 
of  an  insect  that  undergoes  a  true  metamor- 
phosis is  one  continued  series  of  changes  from 
the  period  of  its  leaving  the  egg  to  that  of  its 
assuming  the  perfect  state.  These  are  not 
merely  from  the  larva  to  the  pupa  and  from 
that  to  the  perfect  animal,  during  which  the 
insect  gradually  acquires  new  organs,  but  con- 
sist also  of  repeated  sheddings  of  its  skin,  which 
occur  at  certain  intervals  before  the  larva  has 
attained  its  full  size.  These  changes  and  the 
circumstances  connected  with  them  have  been 
more  particularly  watched  in  Lepidopterous 
insects,  and  have  been  carefully  noted  by  many 
naturalists,  especially  by  those  of  the  last  cen- 
tury, Redi,  Malpighi,  Gcedart,  Merian,  Ray, 
Swammerdam,  Reaumur,  Lyonet,  Bonnet,  De 
Geer,  and  others,  who  concur  in  their  state- 
ments respecting  the  manner  in  which  these 
changes  are  effected. 

Almost  immediately  after  the  insect  is 
liberated  from  the  egg  it  begins  to  feed  with 
avidity,  and  increases  much  in  size.  Accord- 
ing to  the  observations  of  Count  Dandalo*  the 
common  silk-worm,  Liparis  mori,  does  not 
then  weigh  more  than  one  hundredth  of  a  grain, 
and  is  scarcely  a  line  in  length,  but  at  the 
expiration  of  about  thirty  days,  when  it  has 
done  feeding  and  has  acquired  its  full  size,  its 

*  Count  Dandalo  on  Silk-worms  (Eng.  Trans.) 
p.  326. 


INSECTA. 


875 


average  weight  is  about  ninety-five  grains,  and 
its  length  sometimes  as  much  as  forty  lines. 
During  this  period,  therefore,  it  has  increased 
nine  thousand  and  five  hundred  times  its  origi- 
nal weight,  and  has  eaten  sixty  thousand  times 
its  weight  of  food.  But  observations  on  the 
larva  of  the  privet  hawk  moth,  Sphinx  ligustri,* 
lead  us  to  believe  that  this  estimate  of  the 
amount  of  food  eaten  is  a  little  too  great.  The 
larva  of  the  sphinx  at  the  moment  of  leaving 
the  egg  weighs  about  one  eightieth  of  a  grain; 
at  about  the  ninth  day  it  casts  its  second  skin 
and  then  weighs  about  one-eighth  of  a  grain : 
on  the  twelfth  day  it  changes  its  skin  again 
and  then  weighs  rather  more  than  nine-tenths 
of  a  grain.  On  the  sixteenth  day  it  casts  its 
fourth  skin  and  weighs  three  grains  and  a  half, 
and  on  the  twenty-second  day  enters  its  sixth 
and  last  skin  and  weighs  very  nearly  twenty 
grains;  but  on  the  thirty-second  day,  when  it 
has  acquired  its  greatest  size,  it  weighs  nearly 
one  hundred  and  twenty-five  grains,  so  that  in 
the  course  of  thirty-two  days  this  larva  increases 
about  nine  thousand  nine  hundred  and  seventy- 
six  times  its  original  weight.  At  this  period  it 
is  sometimes  more  than  four  inches  in  length. 
But  this  is  not  the  greatest  weight  that  the 
larva  attains.  One  specimen  which  was  bred 
in  its  natural  haunts  weighed  one  hundred  and 
forty-one  grains  and  seven-tenths,  so  that  in 
this  instance  the  insect  had  increased  at  the  rate 
of  eleven  thousand  three  hundred  and  twelve 
times  its  original  weight.  But  great  as  is  this 
proportion  of  increase,  it  is  exceeded  by  some 
other  larvae.  Lyonet  found  that  the  larva  of 
Cussus  ligniperda,  which  remains  about  three 
years  in  that  state,  increased  to  the  amount  of 
seventy-two  thousand  times  its  first  weight.f 
This  amazing  increase  is  occasioned  chiefly  by  a 
prodigious  accumulation  of  fat  which  exists  in 
a  greater  quantity  in  this  than  in  most  other 
larvae.  We  have  ourselves  removed  forty-two 
grains  of  fat  from  one  specimen,  which  was 
more  than  one-fourth  of  the  whole  weight  of 
the  insect.  The  occasion  for  this  prodigious 
accumulation  is  chiefly  to  supply  the  insect 
during  its  continuance  in  the  pupa  state,  while 
the  muscular  structure  of  the  limbs  and  other 
parts  of  the  body  are  in  the  course  of  develop- 
ment; and  also  to  serve,  perhaps,  as  an  imme- 
diate source  of  nutriment  to  the  insect  at  the 
period  of  its  assuming  the  perfect  state,  and 
more  particularly  during  the  rapid  development 
of  its  generative  functions ;  since,  when  these 
have  become  perfected,  the  quantity  that  re- 
mains is  very  inconsiderable.  But  all  larvae  do 
not  increase  in  these  amazing  proportions, 
although  their  actual  increase  may  be  more 
rapid.  Those  in  which  the  proportion  of  in- 
crease is  the  greatest  are  usually  those  which 
remain  longest  in  the  pupa  state,  as  in  the 
species  first  noticed.  Thus  Redit  observed  in 
the  maggots  of  the  common  flesh-flies  a  rate  of 
increase  amounting  to  about  two  hundred  times 
the  original  weight  in  twenty-four  hours,  but 
the  proportion  of  increase  in  these  larvae  does 

*  Phil.  Trans.  1837,  part  ii.  p.  315. 
t  Traite  Anat.  dc  la  Chenille,  p.  11. 
t  Be  Genciat.  Inscitoruni,  p.  27. 


not  at  all  approach  that  of  the  sphinx  and 
cossus.  From  observations  made  on  the  larva 
of  one  of  the  wild  bees,  Anthoplwra  retusa,  we 
believe  that  this  is  also  the  case  with  the  Hy- 
menoptera.  The  weight  of  the  egg  of  this 
insect  is  about  the  one  hundred  and  fiftieth 
part  of  a  grain,  and  the  average  weight  of  a 
full-grown  larva  six  grains  and  eight  tenths,  so 
that  its  increase  is  about  one  thousand  and 
twenty  times  its  original  weight ;  which,  com- 
pared with  that  of  the  sphinx  of  medium  size, 
is  but  as  one  to  nine  and  three-quarters,  and  to 
a  sphinx  of  maximum  size  only  as  one  to  a 
bttle  more  than  eleven. 

The  changes  of  skin  which  a  larva  undergoes 
before  it  enters  the  pupa  state  are  more  or  less 
frequent  in  different  species.  In  the  generality 
of  Lepidopterous  insects  it  occurs  about  five 
times,  but  in  one  of  the  tiger-moths,  Arctia 
Cuja,  according  to  Messrs.  Kirby  and  Spence,* 
ten  times.  A  few  hours  before  the  change  is 
to  take  place  the  larva  ceases  to  eat  and  remains 
motionless,  attached  by  its  abdominal  legs  to 
the  under-surface  of  the  twig  or  leaf  upon 
which  it  has  been  feeding.  Many  species  spin 
a  slight  web  or  carpet  of  silk  in  which  they 
attach  their  posterior  legs,  as  observed  by  Dr. 
Pallas  of  Apatura  iris,f  and  in  this  manner 
await  their  change,  which  appears  to  be  attended 
with  much  uneasiness  to  the  insect.  The  whole 
body  is  wrinkled  and  contracted  in  length.  In 
the  sphinx  this  contraction  occurs  to  so  great 
an  extent  in  some  of  the  longitudinal  muscles 
of  the  anterior  and  middle  part  of  the  body 
that  the  larva  assumes  that  peculiar  attitude 
from  whence  the  genus  derives  its  name.  In 
this  attitude  the  larva  remains  for  several  hours, 
during  which  there  are  occasionally  some 
powerful  contractions  and  twitchings  of  its 
whole  body,  the  skin  becomes  dry  and  shri- 
velled, and  is  gradually  separated  from  a  new 
but  as  yet  very  delicate  one  which  has  been 
formed  beneath  it,  and  the  three  or  four  anterior 
segments  are  greatly  enlarged  on  their  dorsal 
but  contracted  on  their  under  surface.  After 
several  powerful  efforts  of  the  larva  the  old 
skin  cracks  along  the  middle  of  the  dorsal 
surface  of  the  second  segment,  and  by  repeated 
efforts  the  fissure  is  extended  into  the  first  and 
third  segments,  and  the  covering  of  the  head 
divides  along  the  vertex  and  on  each  side  of 
the  clypeus.  The  larva  then  gradually  presses 
itself  through  the  opening,  withdrawing  first  its 
head  and  thoracic  legs,  and  subsequently  the 
remainder  of  its  body,  slipping  off  the  skin 
from  behind  like  the  finger  of  a  glove.  This 
process,  after  the  skin  has  once  been  ruptured, 
seldom  lasts  more  than  a  few  minutes.  When 
first  changed  the  larva  is  exceedingly  delicate, 
and  its  head,  which  does  not  increase  in  size 
until  it  again  changes  its  skin,  is  very  large  in 
proportion  to  the  rest  of  its  body.  In  a  few 
hours  the  insect  begins  again  to  feed  most 
voraciously,  particularly  after  it  has  entered  its 
last  skin,  when  its  growth  is  most  rapid.  Thus 
a  larva  of  Sphinx  ligustri,  which  at  its  last 

*  Vol.  i. 

t  Trans.  lint.  Society,  vol.  ii.  part  ii.  p.  138. 


876 


INSECTA. 


change  weighed  only  about  nineteen  or  twenty 
grains,  at  the  expiration  of  eight  days  when  it 
was  full-grown  weighed  nearly  one  hundred 
and  twenty  grains.  Most  larva?  immediately 
after  changing  their  skins  remove  to  fresh 
plants,  but  some,  as  the  larva?  of  a  beautiful 
moth,  Episema  cairuleocephala,  devour  their  old 
skins  almost  immediately  they  are  cast,  and 
sometimes  one  another  when  deprived  of  food. 

But  it  is  not  merely  the  external  covering 
which  is  thrown  off  during  these  changes  ;  the 
whole  internal  lining  of  the  alimentary  canal 
also  comes  away  with  the  skin,  as  was  formerly 
noticed  by  Swammerdam,*  and  repeatedly  ob- 
served by  ourselves  and  others.  The  lining  of 
the  mouth  and  pharynx  with  that  of  the  man- 
dibles, is  detached  with  the  covering  of  the 
head,  and  that  of  the  large  intestines  with  the 
skin  of  the  posterior  part  of  the  body,  and 
besides  these  also,  the  lining  of  the  tracheal 
tubes.  The  lining  of  the  stomach  itself,  or  that 
portion  of  the  alimentary  canal  which  extends 
from  the  termination  of  the  oesophagus  to  the 
insertion  of  the  so  called  biliary  vessels,  is  also 
detached,  and  becomes  completely  disintegrated, 
and  appears  to  constitute  part  of  the  meconium 
voided  by  the  insect  on  assuming  its  Imago 
state.  Herold,  however,  has  denied  that  this 
change  ever  occurs  in  the  alimentary  canal,  and 
says  that  in  the  trachea  it  takes  place  only  in  the 
larger  stems.  But  Swammerdam  states  that  he 
saw  it  in  the  larva  of  the  rhinoceros  beetle, 
Oryctes  nasicornis,  which  shed  both  the  lining 
of  the  colon,  and  of  the  delicate  as  well  as  larger 
branches  of  the  trachea?,f  and  Bonnet}  had  wit- 
nessed a  similar  occurrence.  Burmeister§  has 
also  seen  it,  both  with  respect  to  the  colon  and 
trachea?,  in  some  of  the  Libellulre,  and  we  now 
add  our  own  testimony  to  the  fact  of  its  occurring, 
not  simply  at  the  extremities  of  the  canal,  but 
throughout  its  whole  extent,  as  we  have  dis- 
tinctly seen  during  the  changes  of  the  nettle-but- 
terfly, Vanessa  urtica.\\  It  is  more  distinctly 
observed  when  the  larva  is  changing  into  the 
pupa  state  than  at  any  other  period,  although 
we  believe  that  it  really  does  take  place  at 
every  change  of  skin.  Hence  these  changes 
are  of  the  greatest  importance  to  the  larvae, 
which  often  perish  during  their  occurrence. 
They  are  undergone  by  all  larva?  which  possess 
the  true  organs  of  locomotion,  but  it  has  been 
questioned  whether  they  are  common  also  to 
the  apodal  larvae,  more  particularly  those  which 
constantly  remain  *in  the  same  locality  until 
they  have  changed  into  pupa?  or  nymphs. 
Reaumur  and  Huberlf  state  that  the  larva  of 
the  common  hive-bee  does  not  change  its  skin, 
but  only  grows  larger ;  Swammerdam,**  on  the 
contrary,  asserts  that  it  does,  and  also  that  he 

*  Biblia  Nat. 

t  Biblia  Nat.  p.  129,  134,  239,  &c. 

$  Contemplation  de  la  Nature,  torn.  ii.  p.  48 

§  Manual  of  Entomology,  (Trans.)  1836,  p.  428. 

||  Since  these  remarks  were  written,  a  paper  by 
Mr.  Ashton  upon  this  subject  has  been  read  at  a 
late  meeting  of  the  Entomological  Society,  Nov.  5, 
1838,  in  which  the  statements  of  Swammerdam 
respecting  these  changes  have  been  fully  confirmed. 

i[  Kirby  and  Spence,  Introduc.  vol.  iii. 

**  Biblia  Nat.  p.  163,  a. 


has  observed  the  same  thing  in  the  alimentary 
canal  of  the  hornet.*  Burmeisterf  believes  that 
it  does  not  take  place,  and  states  positively 
that  the  larvae  of  Diptera  do  not  moult.  We 
have  watched  for  these  changes  in  the  larvae  of 
the  wild  bee,  Anthophora  retusa,  but  have  been 
unable  to  observe  them,  although  we  believe 
they  do  really  occur.  But  the  universally  ac- 
knowledged accuracy  of  most  of  Swammer- 
dam's  observations,  supported  as  they  are  in  this 
instance  by  analogy,  fully  warrants  us  in  con- 
sidering this  subject  as  still  open  for  enquiry. 

When  a  full-grown  larva  is  preparing  to 
change  into  the  pupa  state  it  becomes  exceed- 
ingly restless,  ceases  to  eat,  and  diminishes 
much  in  weight.  Many  species  spin  for  them- 
selves a  covering  of  silk,  termed  a  coccoon, 
or  case,  in  which  they  await  their  transforma- 
tion. Others  prepare  little  cavities  in  the  earth 
and  line  them  with  silk  for  the  same  purpose, 
(fig.  363),  and  others  suspend  themselves  by 


Fig.  363. 


Section  of  the  coccoon  or  winter  nidus  of  Athalia 
centifoliee,  natural  size  and  magnified.  Newport, 
Prize  Essay. 

their  anal  prolegs  to  the  under  surface  of  a  leaf. 
In  each  of  these  instances  this  important  change 
takes  place  in  the  same  manner.  Before  the 
larva  thus  prepares  itself  for  metamorphosis  its 
alimentary  canal  is  completely  evacuated  of  its 
contents,  its  body,  as  at  the  previous  changes  of 
skin,  becomes  dry  and  shrivelled,  and  much 
contracted  in  length,  and  certain  enlargements 
at  the  sides  of  the  anterior  segments  indicate 
the  now  rapidly  developing  parts  of  the  future 
pupa.  These  changes  take  place  in  all  insects 
in  a  similar  manner,  but  have  been  most  fre- 
quently watched  in  Lepidoptera,  upon  which 
also  our  own  observations  have  been  made. 
We  have  also  observed  the  same  changes  in 
Hymenoptera.  The  larva  of  the  sphinx,  when 
it  is  ready  to  undergo  its  changes,  penetrates 
the  earth  to  the  depth  of  a  few  inches,  and 
there  forms  for  itself  a  little  chamber,  in  which 
it  awaits  its  transformation.  But  the  butterfly 
either  fastens  itself  by  a  little  rope  of  silk, 
carried  across  its  thorax,  to  the  under  surface 
of  some  object,  as  a  ceiling,  &c,  or  suspends 
itself  vertically  by  its  prolegs,  with  its  head 
directed  downwards,  as  is  the  case  with  the 
common  nettle  butterfly,  Vanessa  urtica.  We 
have  watched  these  changes  with  much  care  in 

*  Ibid.  p.  133,  a. 
t  Transl.  p.  432. 


INSECTA. 


877 


this  insect,  which  frequently  remains  thus 
suspended  more  than  ten  or  twenty  hours  be- 
fore the  transformation  takes  place.  During 
this  time  the  four  anterior  segments  of  the 
larva  become  greatly  enlarged,  and  the  seg- 
ments assume  a  curved  direction,  occasioned 
by  the  contraction,  or  shortening  of  the  muscles 
of  the  under  surface  of  those  segments,  which 
are  repeatedly  slowly  extended  and  shortened, 
as  if  the  insect  were  in  the  act  of  laborious 
respiration.    This  generally  takes  place  at  short 
intervals  during  the  two  hours  immediately  pre- 
ceding the  change,  and  increases  in  frequency 
as  that  period  approaches.    When  the  period 
has  arrived,  the  skin  bursts  along  the  dorsal 
part  of  the  third  segment,  or  meso-thorax,  and 
is  extended  along  the  second  and  fourth,  while 
the  coverings  of  the  head  separate  into  three 
pieces.    The  insect  then  exerts  itself  to  the 
utmost  to  extend  the  fissure  along  the  segments 
of  the  abdomen,  and  in  the  meantime  pressing 
its  body  through  the  opening  gradually  with- 
draws its  antenna  and  legs,  while  the  skin,  by 
successive  contortions  of  the  abdomen,  is  slip-  . 
ped  backwards  and  forced  towards  the  extre- 
mity of  the  body,  just  as  a  person  would  slip 
off  his  glove  or  his  stocking.  The  efforts  of  the 
insect  to  get  entirely  rid  of  it  are  then  very 
great;  it  twirls  itself  in  every  direction  in  order 
to  burst  the  skin,  and  when  it  has  exerted 
itself  in  this  manner  for  some  time,  twirls 
itself  swiftly,  first  in  one  direction,  then  in  the 
opposite,  until  at  last  the  skin  is  broken  through 
and  falls  to  the  ground,  or  is  forced  to  some 
distance  from  it.    The  new  pupa  then  hangs 
for  a  few  seconds  at  rest,  but  its  change  is  not 
yet  completed.   The  legs  and  antenna,  which 
when  withdrawn  from  the  old  skin  were  dis- 
posed along  the  under  surface  of  the  body,  are 
yet  separate,  and  do  not  adhere  together  as 
they  do  a  short  time  afterwards.  The  wings  are 
also  separate  and  very  small.   In  a  few  seconds 
the  pupa  makes  several  slow  but  powerful 
respiratory  efforts  ;  during  which  the  abdominal 
segments  become  more  contracted  along  their 
under  surface,  and  the  wings  are  much  en- 
larged and  extended  along  the  lateral  inferior 
surface  of  the  body,  while  a  very  transparent 
fluid  which  facilitated  the  slipping  off  of  the 
skin,  is  now  diffused  among  the  limbs,  and 
when  the  pupa  becomes  quiet  dries,  and  unites 
the  whole  into  one  compact  covering.*  Ex- 
actly the  same  thing  occurs  in  the  changes  of 
the  sphinx.    The  limbs  at  first  are  all  separate, 
each  one  inclosed  in  its  distinct  sheath,  but 
within  a  very  short  period  after  the  change  they 
become   agglutinated   together  by  the  fluid 
effused  between  them,  and  form  the  solid  ex- 
terior of  the  pupa  case.    The  body  of  the  insect 
is  now  divided  into  three  distinct  regions,  head, 
thorax,  and  abdomen.    The  first  step  towards 
this  division  is  the  contraction  which  takes  place 
in  all  the  longitudinal  and  diagonal  muscles  of 
the  body,  soon  after  the  larva  (Jig.  364)  has  ac- 
quired its  full  size,  by  means  of  which  each  seg- 
ment of  the  insect  forms  a  slight  intussusception, 
the  anterior  margin  of  one  segment  being  drawn 

*  See  also  Entomologist's  Text-book,  p.  208. 


Fig.  364. 


Section  of  larva  of  Sphinx  ligustri ;  1  to  13,  ( dorsal 
surface )  segments ;  1  to  12,  ( ventral  surface  J  ganglia  • 
a,  dorsal  vessel ;  b,  its  lateral  muscle ;  c  d,  oesophagus 
a?id  stomach ;  e,  ilium  j  f,  hepatic  vessels  ;  g,  caecum 
coli ;  h,  colon  and  rectum  ;  i,  testis  ;  *  *  *  thoracic 
legs ;  t  f  t  abdominal  legs.     Newport,  Phil.  Trans. 

under  the  posterior  margin  of  the  one  which  im- 
mediately precedes  it.  This  occurs  in  all  the 
segments  which  form  the  abdominal  region  of 
the  future  moth,  the  nine  posterior  ones  of  the 
larva.  When  the  period  of  changing  into  the 
pupa  state  has  arrived,  a  much  greater  shortening 
takes  place  in  the  muscles  of  the  fifth  and  sixth 
segments,  and  in  some  insects  this  is  carried  to  so 
greatan  extent  that  the  whole  body  becomes  con- 
stricted in  the  fifth  segment  like  an  hour-glass, 
and  is  thus  divided  into  two  distinct  regions, 
thorax  and  abdomen.  The  same  change  takes 
place  also  in  the  muscles  of  the  first  and  second 
segment,  by  means  of  which  the  region  of  the 
head  is  divided  from  that  of  the  thorax  (Jig.  365). 
These  duplicatures  of  the  external  covering  are 
carried  to  a  greater  extent  on  the  under  surface 
of  the  first  four  segments  than  on  the  upper, 


878  INSECTA. 


Section  of  pupa  of  sphinx  ligustri  ;  1  to  13,  dorsal 
surface,  number  of  segments ;  1  to  12,  ventral  sur- 
face, number  and  position  of  ganglia  ,*  a,  dorsal  ves- 
sel ;  b,  its  lateral  muscles  j  c  d,  (Esophagus  and  sto- 
mach ;  e,  ilium  •  f,  hepatic  vessels ;  g,  colon  ;  h, 
rectum ;  i ,  double  testis ;  k,  brain.  Newport,  Phil, 
Trans. 

and  form  the  divisions  between  the  legs  of  the 
perfect  insect, — the  bony  processes  of  the 
sternal  surface  to  which  some  of  the  principal 
muscles  are  attached.  On  the  upper  surface 
of  the  same  segments  they  in  like  manner  be- 
come the  pkragmata,  or  bony  partitions  of  the 
dorsal  surface.  The  fifth  segment  becomes  al- 
most entirely  atrophied,  and  the  sixth  very 
much  shortened.  A  part  of  the  fifth  segment 
forms  a  portion  of  the  posterior  surface  of  the 
thorax  of  the  perfect  insect,  (fig,  366)  while  the 
remainder  constitutes  the  petiole  or  neck  which 
connects  the  abdomen  with  the  thorax,  the 
sixth  being  the  first  true  segment  of  the  ab- 
dominal region.  Exactly  the  same  changes 
take  place  in  Hymenopterous  insects,  and  in 
every  other  species  in  which  we  have  had 
opportunities  of  watching  them.  We  have 
before  alluded  to  the  opinion  of  Dr.  Ratzeburg 
that  the  head  in  Hymenopterous  insects  is  com- 
posed of  two  segments  of  the  larva,  because 
just  before  the  change  into  the  nymph  or  pupa 
state  a  portion  of  the  head  is  found  beneath  the 
integuments  of  the  second  segment.  The  fact 
is  indisputable,  but  the  explanation  of  it  appears 
to  be  this.  The  true  head  of  the  Hymenopterous 
larva  consists  of  but  one  segment,  which  is 
provided  with  the  organs  of  manducation  and 
sensation  the  same  as  in  the  Lepidopterous. 
But  the  head  in  this  larva  ceases  to  become 
larger  after  a  certain  period,  while  the  other 
segments  of  the  body  continue  to  grow,  and 
ultimately  acquire  a  diameter  more  than  double 
that  of  the  head.  Now  the  parts  which  are 
to  form  the  head  of  the  future  nymph  continue 


Fig.  366. 


Section  of  perfect  state,  Sphinx  ligustri ;  letters  and 
figures  as  in  section  of  pupa.    Newport,  Phil.  Trans. 

also  to  grow  beneath  the  unyielding  cranium, 
from  which,  as  the  change  approaches,  they 
become  detached,  and  are  gradually  developed 
backwards,  and  encroach  upon  the  anterior 
portion  of  the  second  segment.  This,  in  ac- 
cordance with  the  laws  of  development,  as 
established  by  GeofFroy  St.  Hilaire,  that  in 
proportion  as  one  part  of  an  organized  body  is 
increased  beyond  its  ordinary  size,  the  part 
or  parts  in  its  immediate  vicinity  are  in  a  cor- 
responding degree  arrested  in  their  develop- 
ment, becomes  so  much  reduced,  that  in  the 
nymph,  this  second  segment,  which  in  the 
larva  is  of  the  same  size  as  the  third  and  suc- 
ceeding ones,  has  not  half  its  original  extent, 
and  being  still  further  reduced  in  that  state  con- 
stitutes at  length  the  atrophied,  and  almost  ob- 
literated pro-thorax  of  the  perfect  insect.  But 
while  the  second  segment  is  thus  encroached 
upon  by  the  first  it  is  in  like  manner  encroached  ' 
upon  from  behind  by  the  third,  the  immense 
meso-thorax,  which  supports  the  chief  organs 
of  flight  in  the  perfect  insect.  The  fourth 
segment  from  the  same  cause  is  developed 
backwards,  and  the  fifth,  diminished  to  a  very 
small  size,  exists  only  as  in  the  sphinx  as  the 
petiole  which  connects  the  thorax  with  the 
abdomen,  thus  leaving  the  nine  posterior  seg- 
ments of  the  larva  to  the  latter  region,  as  stated 
when  alluding  more  particularly  to  the  number 
of  segments  in  hymenopterous  larvae.  The 
necessity  for  this  additional  segment  in  the 
abdomen  of  these  larvse  is  a  matter  of  much 
interest,  and  appears  to  be  connected  with  the 
development  of  an  apparently  additional  organ 


INSECTA. 


879 


in  the  females  of  this  class,  a  circumstance 
to  which  we  shall  return  in  our  description 
of  the  skeleton  of  the  perfect  insect. 

The  Pupa. — We  have  seen  that  after  leaving 
the  larva  or  feeding  condition,  the  insect  as- 
sumes one  of  a  very  different  form,  which  is 
called  the  pupa,  nymph,  uurelia,  or  chrysalis 
state.  The  two  latter  terms  were  applied  by 
the  older  entomologists  to  this  stage  of  transfor- 
mation in  butterflies  and  moths.  The  term  aure- 
lia  was  used,  as  expressive  of  the  beautiful  gol- 
den colours  or  spots  with  which  many  species  are 
adorned,  as  Vanessa  urtica,  v.  atulanta,  and 
others.  The  term  chrysalis  had  a  similar  sig- 
nification. Linnaeus,  desirous  of  employing  a 
term  that  would  be  applicable  to  this  stage  of 
transformation  in  all  insects,  adopted  that  of 
pupa,  because  in  a  large  majority  of  the  class 
the  insect  is  as  it  were  swathed  (fig.  367)  or 


Fig.  367. 


Pupa  of  Deilephila  Elpenor.    Elephant  hawk-moth. 

bound  up,  as  was  formerly  the  practice  of 
swathing  children.  This  kind  of  pupa,  in 
which  the  future  limbs  are  seen  on  the  out- 
side of  the  case,  is  called  obtected.  The  term 
nymph,  which  is  sometimes  employed,  is 
applicable  only  to  those  species  in  which  the 
limbs  remain  free,  but  are  folded  up,  as  in 
the  pupae  of  the  butterfly  and  moth,  and  are 
not  covered  with  a  hard  uniform  case ;  as  in 
many  Coleopterous  and  most  Hymenopterous 
insects    (fig.  368).    When  the  pupa  is  in- 

Fig.  368. 


J 


closed  in  a  smooth  uniform  case,  but  no  signs 
of  the  limbs  or  other  parts  of  the  body  are 
visible,  as  in  Diptera,  it  is  called  courctate. 
In  these  insects  the  skin  of  the  larva  is  not 
cast  off  at  the  period  of  changing,  but  becomes 
the  covering  or  coccoon  of  the  included  pupa, 
which  is  also  inclosed  in  its  own  proper  skin 
within  it.  In  all  insects  which  undergo  a  com- 
plete metamorphosis,  this  is  the  period  of  quies- 
cence and  entire  abstinence.  Many  species 
remain  in  this  state  during  the  greatest  part 
of  their  existence,  particularly  the  true  pupaa 
of  moths  and  sphinges,  which  often  continue 
in  it  for  nearly  nine  months  of  the  whole 
year.  But  in  most  of  those  insects  which  as- 
sume the  particular  condition  of  nymph,  in 
which  the  body  remains  soft  and  delicate,  as 
the  hornets,  ants,  and  bees,  the  pupa  state  is 
the  shortest  period  of  existence,  being  often 
scarcely  more  than  a  week  or  ten  days.  In 
every  species  the  length  of  this  period  is  much 
affected  by  the  influence  of  external  circum- 
stances. Thus  if  the  larva  of  the  common  net- 
tle-butterfly, Vanessa  urtka,  change  to  a  chry- 
salis in  the  hottest  part  of  the  summer,  it  will 
often,  as  we  have  found,  be  developed  into  the 
perfect  insect  in  eight  or  nine  days;*  whilst  if 
its  change  into  the  chrysalis  takes  place  at 
the  beginning  of  summer,  it  is  fourteen  days 
before  the  perfect  insect  appears  ;  and  if  it  en- 
ters the  chrysalis  state  at  the  end  of  summer,  it 
remains  in  that  condition  through  the  winter 
until  the  following  spring.  On  the  other  hand, 
as  was  proved  by  Reaumur,  if  the  chrysalis  be 
placed  in  an  ice-house,  its  development  into 
the  perfect  insect  may  be  retarded  for  two  or 
three  years.  Again,  if  the  chrysalis  be  taken  in 
the  midst  of  winter  into  a  hot-house,  it  is  deve- 
loped into  the  perfect  insect  in  from  ten  to 
fourteen  days.  This  period  of  quiescence  is 
absolutely  necessary  in  all  those  species  which 
undergo  an  entire  change  of  form  and  habits, 
for  the  completion  of  those  structural  metamor- 
phoses by  which  the  creature  is  not  only  adapted 
to  the  performance  of  new  functions,  but  is 
equally  incapacitated  for  the  continuance  of 
some  of  those  which  it  has  previously  enjoyed. 
During  this  period  it  is  that  new  parts  are  deve- 
loped, and  the  insect's  mode  of  life  is  in  conse- 
quence entirely  changed.  Whilst  these  altera- 
tions are  taking  place  in  the  organic  structures, 
the  functions  of  the  organs  themselves  are  in  a 
great  measure* suspended,  and  the  condition  of 
the  insect  becomes  that  of  the  hybernating  ani- 
mal. Respiration  and  circulation  are  reduced 
to  their  minimum,f  and  the  cutaneous  expendi- 
ture of  the  body  is  then  almost  unappreciable 
even  by  the  most  delicate  tests.];  Thus  a  pupa 
of  Sphinx  ligustri,  which  in  the  month  of  Au- 
gust, immediately  after  its  transformation, 
weighed  71.1  grains,  in  the  month  of  April  fol- 
lowing weighed  67.4  grains,  having  thus  lost 
only  3.7  grains  in  the  long  period  of  nearly 
eight  months  of  entire  abstinence.  The  whole 
of  this  expenditure,  therefore,  had  passed  off 


Nymph  or  pupa  state  of  Vespa  crabo.  Hornet. 
Magnified. 


*  Phil.  Trans.  1834,  part  2,  p.  416. 
t  Phil.  Trans.  1836,  part  2,  pp.  555-6. 
i  Idem.  1837,  part  2,  p.  323. 


880 


INSECTA. 


by  the  cutaneous  and  respiratory  surfaces.  But 
when  the  changes  in  the  internal  structures  are 
nearly  completed,  and  the  perfect  insect  is  soon 
to  be  developed,  the  respiration  of  the  pupa  is 
greatly  increased,  and  the  gaseous  expenditure 
of  its  body  is  augmented  in  the  ratio  of  the 
volume  of  its  respiration,  which  is  greatest  the 
nearer  the  period  of  development.  Thus  in  the 
same  insect  in  which  the  diminution  of  weight 
was  so  trifling  during  eight  months'  quiescence 
and  abstinence,  it  amounted  in  the  succeeding 
fifty-one  days  to  nearly  half  the  original  weight 
•of  the  pupa,  since  the  perfect  insect,  imme- 
diately after  its  appearance  on  the  24th  of  May, 
weighed  only  thirty-six  grains. 

This  increased  activity  of  function  is  attended 
with  a  correspondent  alteration  in  the  general 
appearance  of  the  pupa.  In  the  sphinx  all  the 
parts  of  the  future  Imago  become  more  and 
more  apparent  on  the  exterior  of  the  pupa  case, 
the  divisions  into  head,  thorax,  and  abdomen 
are  more  distinctly  marked,  the  eyes,  the  an- 
tennae, and  the  limbs  appear  as  if  swollen  and 
ready  to  burst  their  envelope,  and  the  pupa 
gives  signs  of  increasing  activity  by  frequent 
and  vigorous  contortions  of  its  abdominal  seg- 
ments. The  naked  pupa  or  nymph,  in  which, 
as  we  have  seen,  all  the  parts  of  the  body  are 
free,  and  encased  only  in  a  very  delicate  mem- 
brane, acquires  a  darker  colouring  and  a  firmer 
texture,  while  the  species  which  undergo  their 
metamorphoses  into  nymphs  in  the  water,  Tri- 
choptcra,  the  caddis-flies,  acquire  a  power  of  lo- 
comotion as  the  period  of  their  full  develop- 
ment approaches,  to  enable  them  to  creep  up 
the  stems  of  plants,  and  leave  that  medium  in 
which  it  is  impossible  for  them  to  exist  as  per- 
fect insects. 

In  every  instance  the  assumption  of  the  per- 
fect state  is  accompanied  by  a  slipping  off  of 
the  external  covering.  Before  this  can  be  ef- 
fected, many  Lepidoptera,  like  the  Trichoptera, 
have  first  to  remove  themselves  from  the  locality 
in  which  they  have  undergone  their  previous 
metamorphoses.  When  this  happens  to  be  in 
the  interior  of  the  trunks  of  trees,  or  in  other 
situations  from  which  it  is  difficult  to  escape, 
the  abdominal  segments  of  the  pupa  are  often 
beset  with  minute  hooks  (fig.  367),  similar  to 
those  on  the  feet  of  the  larva.  By  means  of 
these,  by  alternately  contracting  and  extending 
its  abdominal  segments,  the  pupa  is  enabled  to 
force  an  opening  through  its  silken  coccoon,  or 
to  move  itself  along  until  it  has  overcome  the 
obstacles  which  might  oppose  its  escape  as  a 
perfect  insect. 

The  imago  or  perfect  state. — Immediately 
after  the  insect  has  burst  from  the  pupa  case  it 
suspends  itself  in  a  vertical  position  with  its 
new  organs,  the  wings,  somewhat  depending, 
and  makes  several  powerful  respiratory  efforts. 
At  each  respiration  the  wings  become  more  and 
more  enlarged  by  the  expansion  and  extension 
of  the  tracheal  vessels  within  them,  accompa- 
nied by  the  circulatory  fluids.  When  these 
organs  have  acquired  their  full  development 
the  insect  remains  at  rest  for  a  few  hours  and 
gains  strength,  and  the  exterior  of  the  body  be- 
comes hardened  and  consolidated,  and  forms, 


what  we  shall  presently  consider,  the  Dermo- 
skeleton.  This  is  what  takes  place  in  Lepidop- 
terous  insects.  Some  of  the  Coleoptera,  as  in 
the  instance  of  Melolontha  vulgaris,  the  com- 
mon chaffer-beetle,  remain  for  a  greater  length 
of  time  in  their  nidi  before  they  come  abroad 
after  entering  the  imago  state.  This  is  also  the 
case  with  the  Humble-bees.  When  these  in- 
sects first  come  from  their  cells  they  are  exceed- 
ingly feeble,  their  bodies  are  soft,  and  covered 
with  moisture,  their  thick  coating  of  hairs  has 
not  acquired  its  proper  colour,  but  is  of  a  gray- 
ish white,  and  they  are  exceedingly  susceptible 
of  diminished  warmth.  They  crowd  every 
where  among  the  cells,  and  among  other  bees, 
where  there  is  most  warmth.  In  a  few  hours 
this  great  susceptibility  is  diminished,  and  their 
bodies  acquire  their  proper  colours,  but  they 
do  not  become  sufficiently  strong  to  be  capable 
of  great  muscular  exertion,  and  undertake  the 
labours  of  the  nest  until  the  following  day. 

When  an  insect  has  once  entered  its  perfect 
state,  it  is  believed  to  undergo  no  further  meta- 
morphosis or  change  of  covering.  But  there 
exists  an  apparent  exception  to  this  general  law 
in  the  Ephemeridte,  which  are  noted  for  the 
shortness  of  their  existence  in  the  imago  state. 
When  these  insects  have  crept  out  of  the  water, 
and  rid  themselves  of  the  pupa  covering,  and 
their  wings  have  become  expanded,  they  soon 
take  flight,  but  their  first  movements  in  the  air 
are  performed  with  some  difficulty,  and  they 
shortly  alight  again  and  throw  off  a  very  deli- 
cate membrane  with  which  every  part  of  the 
body  has  been  covered,  and  then  resume  their 
flight  with  increased  activity.  The  condition 
of  the  insect  previously  to  this  final  change  has 
been  called  by  Mr.  Curtis  the  pseudimago  state. 
It  was  noticed  long  ago  by  Swammerdam,  and 
has  usually  been  thought  to  be  peculiar  to  the 
Ephemeridte,  but  occurs  also  in  the  Lepidoptera 
and  Diptera,*  but  in  them  takes  place  at  the 
same  time  with  the  change  from  the  pupa  state. 
Swammerdam  thought  the  change  peculiar  to 
the  males  of  the  Ephemeridte,  but  Mr.  West- 
wood  has  seen  it  also  in  the  females. 

Many  insects,  of  which  the  Ephemeridte  arid 
Bombycidte  are  known  examples,  take  no  food 
in  the  perfect  state,  and  exist  only  for  a  few 
hours,  or  at  most  only  a  few  days,  the  business 
of  life  being  almost  entirely  devoted  to  the  pro- 
pagation of  the  species.  In  every  instance  of 
the  entire  abstinence  of  a  species  in  the  perfect 
state  there  is  a  corresponding  atrophy  of  the 
parts  of  the  mouth.  This  we  shall  find  is  the 
case  in  the  Ephemera,  in  the  gad-fly,  (Estrus, 
and  in  the  silk-worm  moth.  In  the  latter  in- 
stance the  parts  of  the  mouth  are  simply  so 
much  diminished  in  size  as  to  be  unfitted  for 
taking  food;  in  the  former  they  have  almost 
disappeared.  On  the  other  hand,  when  the  life 
of  the  imago  is  continued  for  a  long  period,  all 
the  parts  of  the  mouth  are  fully  developed. 
The  duration  of  life  in  these  species  often  ex- 
tends for  many  weeks,  or  in  some  even  months, 
and  the  quantity  of  food  taken  is  consequently 
greater  than  is  taken  by  the  larva.    In  those 

*  Westwood's  Introduction,  &c.  vol.  ii.  p.  28. 


INSECTA. 


881 


instances  in  which  the  life  of  the  imago  is  ex- 
tended beyond  the  usual  period,  it  appears  to 
result  from  one  of  the  great  objects  of  existence 
being  unaccomplished;  the  insect  is  always  in 
a  state  of  celibacy,  in  which  condition  the  life 
of  an  ephemera  may  be  extended  to  several 
days,  and  perhaps  even  to  two  or  three  weeks.* 
1.  Dermo-skeleton. — The  skeleton  of  insects 
is  formed  of  a  modification  of  the  external 
coverings  of  the  body,  together  with  certain 
ossified  portions  situated  within  the  head  and 
thorax,  to  which  some  of  the  most  important 
muscles  are  attached.  Hence  it  is  called  a 
dermo-skeleton.  The  true  organs  of  support  are 
thus  placed  on  the  exterior  instead  of  the  inte- 
rior of  the  body,  and  the  solid  skeleton,  impact- 
ing the  whole,  as  it  were,  in  a  coat  of  mail,  gives 
additional  strength  to  the  delicate  limbs  by 
affording  a  larger  surface  for  the  attachment  of 
muscles,  while  it  more  securely  protects  the 
bodies  of  these  diminutive,  but  exquisitely 
formed  little  creatures,  from  the  injuries  to 
which  they  are  constantly  exposed.  Thus,  then, 
in  the  strength  and  position  of  the  skeleton,  in- 
sects have  as  striking  affinities  with  the  Chelo- 
nian  Reptiles  as  they  have,  as  we  shall  hereafter 
see,  with  Birds  in  the  extent,  distribution,  and 
activity  of  their  respiratory  organs;  and  with 
the  hibernating  Mammalia  in  their  maintaining 
an  elevated  temperature  of  body  only  when  in  a 
state  of  activity.  Some  naturalists,  however, 
have  contended  that  the  analogies  which  were 
traced,  first  by  our  illustrious  countryman 
Willis  in  the  year  1692,  and  subsequently 
by  Geoffroy  St.  Hilaire  and  other  comparative 
anatomists,  between  the  dermo-skeleton  of  in- 
sects and  the  proper  skeleton  of  vertebrated  ani- 
mals, are  incorrect,  and  that  the  structure  ought 
rather  to  be  regarded  as  the  analogue  of  the 
skin  than  as  that  of  the  osseous  system,  and 
hence  they  have  compared  it  only  with  the 
nails,  horns,  and  other  appendages  of  the  epi- 
dermis. These  objections  receive  additional 
•weight  and  importance  from  the  circumstance 
that  one  set  of  organs,  the  elytra,  which  form 
part  of  the  hardened  coverings,  are  actually  de- 
rived from  the  respiratory  structures.  But  it  may 
be  remarked  in  reply,  that  the  skeleton  of  in- 
sects, both  in  its  office  and  ultimate  composition, 
resembles  more  the  bones  of  Chelonian  Reptiles, 
which,  like  it,  are  covered  with  a  thin  cuticular 
lamella,  and  placed  on  the  exterior  of  the  body, 
than  the  true  skin  or  the  epidermis.  Hence  we 
shall  continue  to  regard  and  describe  it  as  sub- 
servient to  the  same  purposes  in  these  diminu- 
tive creatures  as  the  osseous  system  in  vertebrata. 
This  view  of  its  real  nature  is  justified,  as  we 
shall  presently  see,  by  analyses  of  its  chemical 
constituents.  The  peculiar  characteristic  of 
bony  structure  is  the  presence  of  a  large  propor- 
tion of  a  particular  kind  of  earthy  matter,  and 
this  is  also  one  of  the  great  characteristics  of  the 
coverings  of  insects,  which  become  consolidated 
during  the  changes,  by  the  deposition  of  a  quan- 
tity of  the  same  kind  of  earthy  matter  within 
them.  But  we  cannot  regard  the  coverings  thus 
formed  as  merely  exsiccated  non-vascular  slruc- 

*  Op.  cit.  p.  27. 

VOL.  II. 


tures  ;  on  the  contrary,  we  believe  them  to  be 
nourished  by  the  circulatory  fluids,  perhaps  to 
as  great  an  extent  as  the  external  skeleton  of 
Chelonia.  In  support  of  this  opinion  it  may  be 
remarked  that  those  internal  processes  which 
exist  in  the  perfect  state,  and  are  developed 
during  the  metamorphoses  from  duplicatures  of 
the  external  tegument,  perform  most  important 
offices  in  the  body  as  organs  of  support  and 
attachment  for  powerful  muscles.  It  can  hardly 
be  imagined  that  these  internal  processes  are 
not  nourished  by  the  circulatory  fluids  like  the 
muscles  that  are  attached  to  them,  while  it  is  well 
known  that  every  part  of  the  external  covering  is 
penetrated  by  ramifications  of  the  air-vessels,  the 
course  of  which  in  the  wings  has  recently  been 
shown  to  be  always  indicative  of  the  passages 
along  which  the  blood  circulates.*  Hence  it 
is  fair  to  infer  that  every  part  of  the  animal  sup- 
plied with  tracheae  is  also  nourished  by  the  cir- 
culatory fluid,  as  well  in  the  exterior  skeleton  of 
the  thorax  and  abdomen  as  in  the  hardened  elytra 
and  wings,  in  which  the  presence  of  the  fluid 
has  been  actually  detected  by  its  movements. 

Chemical  composition. — The  peculiar  sub- 
stance that  constitutes  the  hard  portion  of  the 
dermo-skeleton  is  called  chitinc  by  Odier,  and 
entomoline  by  Lassaigne.  The  most  generally 
received  name  is  chitine.  M.  Odier,  who  first 
analysed  the  coverings  of  insects,  and  disco- 
vered this  substance,f  found  that  it  constitutes 
about  one-fourth  part  of  their  whole  weight, 
and  that  the  remaining  three  parts  consist  of 
albumen,  extractive  matter  soluble  in  water,  a 
coloured  oil  soluble  in  alcohol,  and  a  brown 
animal  substance  soluble  in  potass,  but  insolu- 
ble in  alcohol.  The  latter  substance,  which 
exists  in  considerable  quantity,  was  found  by 
Lassaigne  to  be  analogous  to  the  peculiar  ani- 
mal matter  of  cochineal,  coccine,  and  that  it 
forms  the  basis  of  the  colouring;  matter  of  the 
skeleton.  The  composition  of  chitine  has  been 
differently  stated  by  chemists,  but  by  all  it  has 
been  shown  to  be  perfectly  distinct  from  horn, 
the  nails,  and  other  appendages  of  the  epidermis, 
in  being  quite  insoluble  in  a  hot  solution  of 
caustic  potass,  and  in  not  fusing  or  swelling  up 
like  horn  when  burnt  at  a  red  heat,  but  leaving 
a  white  ash,  which  retains  the  original  form  of 
the  part.  This  sufficiently  proves  that  the  co- 
verings of  insects  cannot  properly  be  compared 
with  the  mere  epidermis  or  its  appendages. 
According  to  Odier,  chitine  is  obtained  by  di- 
gesting the  hard  parts  of  the  skeleton  in  a  hot 
solution  of  caustic  potass,  renewed  several 
times,  until  it  has  ceased  to  have  any  action 
upon  them.  The  solution,  by  removing  the 
colouring  matter  and  other  constituents,  be- 
comes of  a  deep  brown,  and  leaves  the  chitine 
nearly  as  transparent  as  horn,  without  any 
change  of  form.  This  substance,  as  we  have 
before  stated,  constitutes  about  one-third  or 
fourth  of  the  weight  of  the  whole  skeleton,  and 
was  believed  by  Odier  to  contain  no  nitrogen, 

*  Bowerbank,  Observations  on  the  circulation  of 
blood  and  the  distribution  of  the  trachea?  in  the  win"- 
of  Chrysopa  perla,  Ent.  Mag.  No.  17,  Oct.  1836.° 

t  Memoires  de  la  Societe  d'Hist.  Natur.  de  Paris, 
torn.  i.  Zoological  Journal,  vol.  i.  p.  101,  Mav.1824. 

3  M 


882 


INSECTA. 


on  which  account  it  was  compared  by  him  to 
lignin,  the  basis  of  woody  fibre.  He  believed 
also  that  it  contains  no  carbonate  of  lime,  the 
earthy  salts  being  chiefly  phosphate  of  lime, 
with  carbonate  of  potass  and  a  little  phosphate 
of  iron.  Mr.  Children,  however,  by  a  more 
careful  and  different  mode  of  analysis,  proved 
that  chitine  is  composed  of  carbon,  hydrogen, 
nitrogen,  and  oxygen,  in  about  the  following 
proportions,  the  mean  which  we  have  deduced 
from  his  details  of  two  careful  analyses : 


Grs. 

Carbon  

46.08 

Hydrogen  . .'. . 

  5.96 

Nitrogen    . . . . 

10.29 

,  37.41 

99.74 

and  that,  in  addition  to  the  earthy  salts  men- 
tioned by  Odier,  there  are  also  small  propor- 
tions of  silica  and  magnesia,  and  a  slight  trace 
of  manganese ;  and  it  has  since  been  stated 
that  there  is  likewise  a  trace  of  carbonate  of 
lime.*  Some  authors  still  imagine  that  chitine 
contains  no  nitrogen;!  but  in  the  careful  expe- 
riments of  Mr.  Children,  who  was  assisted  by 
Professor  Datiiell,J  the  formation  of  prussic 
acid,  which  took  place  during  the  analysis,  was 
decisive  of  the  fact  of  its  existence. 

Thus,  then,  in  the  distinctness  of  its  chemical 
composition  from  that  of  horn  and  other  dermal 
appendages,  and  in  its  similarity  to  that  of  true 
bone,  in  the  greater  proportion  of  its  earthy 
matter  being  phosphate  of  lime,  may  we  not 
venture  to  infer  that  chitine,  the  basis  of  the 
insect  skeleton,  is  intermediate  in  its  chemical 
condition  between  the  ossific  and  dermal  struc- 
tures ;  or,  in  other  words,  is  an  imperfectly  de- 
veloped condition  of  bony  matter,  so  modified 
that,  while  it  is  subservient  to  the  great  purpose 
of  animal  life,  in  affording  strength  and  solidity 
to  the  parts  in  which  it  exists,  it  at  the  same 
time  admits  of  their  performing  all  the  organic 
functions  of  the  true  skin  ? 

If  such  be  not  the  case,  it  will  be  difficult 
satisfactorily  to  account  for  the  solidification  of 
those  internal  processes  which,  in  insects,  occupy 
the  position  and  perform  the  office  of  the  true 
bones  in  vertebrata,  but  which  are  originally  deri- 
ved from  the  external  teguments.  Thus  we  shall 
find  that  in  the  cranium  of  some  of  the  Coleop- 
tera,  the  most  perfect  insects,  the  cerebral  gan- 
glia are  protected  on  either  side  by  more  or  less 
perfectly  developed  lamina?  of  this  bone-like 
structure;  that  the  first  subcesophageal  ganglion 
actually  lies  in  a  cradle  of  the  same,  and  that 
the  nervous  cord  itself,  before  passing  out  of 
the  cranium,  is  not  only  protected  laterally  by 
continuations  of  these  laminae,  but  is  often  in- 
closed in  a  distinct  bony  ring.  But  it  may  be 
said  that  the  exuviation  of  the  coverings  of  in- 
sects during  the  early  period  of  life,  when  un- 

*  Professor  Owen's  Lectures  at  the  Royal  Col- 
lege of  Surgeons,  May  1837. 

t  Professor  Grant,  Lancet,  Dec.  7,  1833,  p.  393. 
Burmeislor,  Manual  of  Entomology,  (translation.) 
1836,  p.  230. 

%  Zoological  Journal,  March  1824,  p.  115. 


dergoing  their  metamorphoses,  and  a  like  con- 
dition in  other  articulata,  is  opposed  to  this 
opinion.  To  this  we  reply,  that  in  all  true  in^ 
sects  exuviation  of  the  skeleton  takes  place 
only  during  the  growth  and  metamorphoses  of 
the  individual,  and  that  when  these  are  com- 
pleted, and  the  insect  has  arrived  at  its  adult 
condition,  when  its  body  no  longer  continues  to 
be  enlarged,  the  then  perfect  skeleton  is  per- 
sistent throughout  the  remainder  of  life,  which, 
as  in  the  hive-bee,  may  continue  for  many 
months,  and  under  some  circumstances,  as  has 
been  known  among  the  Coleoptera,  even  for 
two  or  three  years.  The  exuviation  of  the  ske- 
leton of  Crustacea,  which  are  said  to  continue 
to  grow  throughout  the  whole  period  of  their 
existence,  is  similar  to  that  of  insects,  and  per- 
haps in  both  is  induced,  not  alone,  as  usually 
supposed,  by  the  mere  incasement  of  the  animal 
in  a  covering  which  prevents  the  further  growth 
of  its  body,  but  by  changes  in  the  actual  con- 
dition of  the  skeleton  itself,  dependent  upon 
the  same  laws  of  existence  which  regulate  the 
removal  of  the  old  and  the  deposition  of  new 
matter  in  the  bones  and  other  structures  of  the 
vertebrata. 

Of  the  manner  in  which  chitine  is  deposited 
in  insects  we  have  no  direct  information. 
Latreille  considers  it  to  be  a  solidification  in  the 
mucous  tissue,  and  Dr.  Grant  affirms  it  to  be 
a  deposition  upon  the  true  skin.  This  appears 
also  to  have  been  the  opinion  of  Odier,  who 
found  chitine  in  theexuviable  skeleton  of  Crus- 
tacea, in  which  he  says  it  exists  in  the  form  of 
lamellae.*  In  whatever  form  it  is  deposited,  it 
is  intimately  connected  with  the  true  corium, 
into  the  composition  of  which  it  appears  to 
enter.  It  is  covered  by  the  colouring  matter, 
and  also  with  a  distinct  epidermis  like  the 
horny  cuticle  on  the  carapace  of  Chelonia.  On 
comparing  the  experiments  of  M.  Odier  and 
Mr.  Children  the  quantity  of  chitine  appears  to 
vary  a  little  in  different  insects.f  A  curious 
circumstance  mentioned  also  by  Odier  is  that 
it  appears  to  enter  into  the  composition  of  the 
tracheae  of  the  wings,  but  not  into  that  of  their 
connecting  membranes.  If  this  be  the  case,  it 
is  a  further  proof  that  the  skeleton  ought  not  to 
be  compared  to  the  epidermal  appendages  of 
vertebrata. 

The  skeleton  consists  of  thirteen  distinct  seg- 
ments, which  are  believed  to  be  its  normal 
number  in  all  insects.  But  recent  observations 
on  the  larvae  of  Hytnenoptera  and  Diptera, 
before  alluded  to,  render  it  probable  that  this  is 
not  the  full  amount,  and  that  the  number  is  at 
least  fourteen,  at  all  events  in  some  species. 
Mr.  VVestwood  has  already  shown  this  to  be 
the  case  in  Hymenoptera,  and  that  in  the  per- 
fect state  of  ForJicula%  there  are  thirteen  dis- 
tinct segments  in  the  male,  and,  also  in  a 
rudimentary  state,  in  the  female,  besides  the 
anal  forceps.  We  have  ourselves  invariably 
found  fourteen  in  the  apodal  larvae  of  Hymen- 
optera and  in  some  of  the  Diptera;  but  we 

*  Zoological  Journal,  vol.  i.  March,  1824,  p.  108. 
+  Op.  cit, 

J  Trans.  Ent.  Society,  vol.  i.  p.  157,  et  seq. 


INSECTA. 


883 


were  not  prepared  to  meet  with  anything  like 
an  approach  to  the  same  number  in  a  perfect 
insect.    In    the  female  of  the  Gryllotalpa 
vulgaris  we  have  found  nine  distinct  segments 
in  the  abdomen,  besides  the  post-scuteHum, 
which  resembles  a  tenth  one  in  a  rudimen- 
tary condition  on  the  dorsal  surface  between 
the  meta-thorax  and  base  of  the  abdomen.  In 
the  male  of  the  same  species  there  are  also  nine 
distinct  segments,  but  the  penultimate  and 
ante-penultimate  are  in  a  rudimentary  con- 
dition, corresponding  to  those  in  the  female 
Forficula.    The  post-scutellum  at  the  base  of 
the  meta-thorax  is  as  much  developed  as  in 
the  female,  and  is  very  distinct  as  a  portion 
of  the  meta-thorax.     We  have  also  found 
the  same  number  in  a  foreign  species,  Gryl- 
lotalpa didactyla.    The  similarity  in  the  num- 
ber of  segments  thus  appears  to  connect  the 
Gryllotulpa;  with  the  Forficula.    These  va- 
riations in  perfect  insects  lead  us  to  hesitate 
in  admitting  thirteen  to  be  the  normal  number 
of  segments,  especially  as  we  shall  presently 
endeavour  to  show  that  the  head  itself  is  com- 
posed of  more  than  one.    The  varied  forms  of 
the  body  in  the  different  classes  are  entirely 
dependent  upon   the  extent   to  which  these 
primary  segments  are  developed,  whatever  be 
their  true  number,  and  chiefly  upon  the  greater 
or  less  development  of  parts  of  the  first  four  seg- 
ments.   But  whether  the  changes  in  these  seg- 
ments be  greater  or  less,  they  are  always  in 
reference  to  the  habits  or  economy  of  the  mdi- 
dividual.    Thus  in  the  Coleoptera  and  Orthop- 
tera  the  parts  of  the  mouth  are  nearly  equally 
developed,  and  are  admirably  fitted  for  all  the 
purposes  of  manducation.    In  the  Lcpidoptera 
some  of  these  parts  are  developed  to  their 
greatest  possible  extent,  the  consequence  of 
which  is  that  the  neighbouring  parts  become  atro- 
phied,  and  leave  scarcely  a  trace  of  their  former 
existence.    This  is  the  case  with  the  mandibles 
and  lips,  the  most  conspicuous  parts  of  the 
mouth  in  the  larvae  of  this  order.    In  the  imago 
the  maxillasare  greatly  elongated,  and  altered  in 
shape,  to  form  a  flexible  tube,  because  the  per- 
fect insects  are  destined  to  take  their  food  in  a 
liquid  state,  and  because  still  further,  the  food 
is  produced  in  situations  where  it  would  be  in- 
accessible to  the  insect,  were  the  mouth  of  the 
same  form  as  in  those  the  food  of  which  re- 
quires to  be  comminuted  by  the  jaws,  before  it 
is  passed  into  the  stomach.*  Then  again  in  the 
same  segment  in  which  the  oral  organs  are 
nearly  equally  developed,  other  parts  are  often 
enlarged,  and  in  like  manner  encroach  upon 
those  which  are  in  immediate  connexion  with 
them.     In  the  rapacious  Neuroptera  which 
obtain  their  food  solely  by  means  of  the  organs 
of  vision,  and  are  constantly  hawking  in  search 
of  it  in  the  brightest  light,  the  corneas  of  the 
eyes  are  expanded  over  nearly  two-thirds  of  the 
whole  surface  of  the  head,  and  in  consequence 
reduce  to  their  minimum  of  development  those 
parts  which  are  most  conspicuous  in  the  head 
of  Coleoptera,  which  usually  obtain  their  food 

*  See   Newman  on  the  External  Anatomy  of 
Insects,  p.  13. 


by  the  aid  of  other  senses.  The  causes  which 
regulate  the  development  of  the  segments  of  the 
thorax  are  exactly  those  which  influence  the 
development  of  the  head.  In  the  mole-cricket, 
which  burrows  in  the  earth  for  its  food,  the 
second  segment,  or  pro-thorax,  with  its  ap- 
pendages the  anterior  extremities,  is  enlarged 
to  its  greatest  extent,  because  it  is  necessary 
that  nearly  the  whole  strength  of  the  insect 
should  be  concentrated  in  this  segment,  to 
enable  it  to  dig  its  way  with  ease  and  rapidity 
through  a  resisting  medium,  while  the  third 
and  fourth  segments,  which  bear  the  organs  of 
flight,  in  this  species  of  minor  importance,  are 
smaller  than  in  most  other  insects.  In  the 
Coleoptera,  Geotrupidic,  which  not  only 
burrow  in  the  earth,  but  require  to  be  trans- 
ported from  place  to  place  in  quest  of  food, 
the  pro-thoracic,  and  the  wing-bearing  meta- 
thoracic  segments  are  largely  developed,  and 
form  a  great  proportion  of  die  body,  and  the 
intermediate  segment,  the  meso-thoracic,  en- 
croached upon  by  both,  is  almost  atrophied 
between  them.  On  the  other  hand,  in  the  Hy- 
menoptera,  Lepidoptera,  and  Diptera,  in  which 
the  principal  organs  of  locomotion  are  the 
anterior  wings,  the  meso-thoracic  segment  is 
enormously  enlarged,  and  the  pro-thorax  and 
meta-thorax  are  reduced  to  a  size  of  compara- 
tive insignificance. 

These  important  modifications  of  structure, 
by  means  of  which  every  part  of  the  body  is 
beautifully  adapted  to  the  habits  and  wants  of 
the  individual,  and  the  insect  itself  becomes  an 
agent  employed  by  nature  to  work  certain 
necessary  effects  on  other  parts  of  Creation,  are 
accomplished  during  the  metamorphoses  by  cer- 
tain changes  in  the  form  of  parts  of  the  external 
teguments.  By  this  means  many  insects  which  in 
their  naked  larva  condition  scarcely  at  all  differ 
in  their  general  external  appearance,  are  made 
to  assume  forms,  when  they  have  undergone 
their  metamorphoses,  so  totally  distinct  from 
each  other  as  to  be  instantly  recognisable  by  the 
most  unpractised  observer.  The  primary  divi- 
sion of  the  body  into  segments  is  effected  simply 
by  a  duplicative  of  the  external  covering.  One 
margin  of  the  fold  is  carried  over  the  other,  and 
a  simple  telescope  articulation  is  produced. 
In  this  way  the  body  of  the  larva  in  its  earliest 
condition  is  first  divided  into  its  normal  num- 
ber of  segments,  and  by  a  continuation  of  the 
same  process,  as  we  have  before  shown,  into 
distinct  regions. 

The  articulations  of  the  limbs  and  organs  of 
manducation  are  as  much  the  result  of  changes 
in  the  form  of  the  external  surface  as  the  divi- 
sion of  the  body  into  segments  or  regions. 
The  folding,  the  intussusception,  the  depression, 
or  the  extension  of  certain  portions  of  the  inte- 
gument, when  solidified,  at  the  completion  of 
the  metamorphoses,  serve  all  the  offices,  and 
become  parts  of  the  different  kinds  of  articula- 
tions, which  in  principle  are  precisely  similar 
in  insects  to  some  of  the  more  important  ones  in 
the  Vertebrata.  In  the  simple  approximation  of 
two  surfaces,  completely  solidified,  and  allowing 
of  no  motion  between  them,  we  discover  the 
common  sutural  connexion  of  some  of  the 
3  m  2 


884 


INSECTA. 


bones  in  man.  An  instance  of  this  occurs  in 
the  upper  surface  of  the  cranium  of  every  insect, 
in  the  union  of  the  clypeus  posterior  with  the 
epicranium.  In  another  duplicature,  one  sur- 
face of  which  is  rendered  concave,  and  the  cor- 
responding one  opposed  to  it  convex,  and 
allowing  of  motion  between  them  almost 
wholly  in  one  plane,  we  perceive  the  true 
gingli/moid  or  hinge-like  articulation ;  while 
the  small  intervening  portion  of  tegument,  by 
means  of  which  the  margins  of  these  surfaces 
are  connected,  becomes  thinned  and  atrophied, 
and  forms  their  proper  connecting  ligament. 
Instances  of  this  kind  of  articulation  occur  also 
in  the  head  of  most  insects  in  the  articulation 
of  the  mandibles  with  the  cranium,  as  well  as 
in  the  limbs  of  almost  every  species.  Again, 
when  a  portion  of  the  tegument  which  covers 
the  developing  organs  of  locomotion  becomes 
constricted  at  the  base  of  the  organ,  that  surface 
of  the  duplicature  which  is  nearest  the  body 
forms  a  hollow  or  cup-shaped  cavity,  into 
which  the  other  surface  of  the  duplicature, 
rendered  convex,  is  inserted,  and  in  this  way 
a  true  enarthrodial  or  cotyloid  articulation  is 
developed,  the  connecting  ligament  between 
the  two  surfaces  forming  the  internal  ligament 
of  the  joint,  which  is  thus  rendered  capable 
of  most  extensive  rotation.  The  ligament  thus 
formed  in  every  instance  is  hollow,  to  allow  a 
passage  for  the  muscles  and  other  structures 
of  the  limb.  Examples  of  this  kind  of  articu- 
lation occur  in  the  coxas  or  basial  joints  of  the 
legs,  in  the  Cerambt/cida  and  Curculionidte. 
Lastly,  where  the  tegument  is  simply  reflected 
upon  itself,  and  a  sliding  motion  allowed  of, 
we  have  the  simple  squamous  articulation.  In 
all  cases  the  development  of  one  portion  of  tegu- 
ment takes  place  at  the  expense  of  another,  as  in 
the  development  of  the  segments  themselves, 
and  not  by  the  introduction  of  a  new  element 
in  the  composition  of  the  part.  In  this  manner, 
in  accordance  with  the  law  of  centripetal  deve- 
lopment as  pointed  out  by  M.  Serres  in  the 
vertebrated  classes,  every  part  of  the  body  is 
formed  in  the  so-called  in  vertebrated. 

We  thus  recognise  four  distinct  kinds  of 
articulation,  although  several  more  have  been 
described  by  Straus-Durckheim  in  his  excellent 
work  on  Melolontha,*  but  all  of  them  appear 
to  be  reducible  to  these  primary  ones. 

These  principles  will  enable  us  to  understand 
the  cause  of  the  presence  or  absence  of  those 
structures  which  form  the  internal  skeleton,  and 
also  the  manner  in  which  the  limbs  of  the 
imago  are  developed  from  the  soft  and  uniform 
body  of  the  naked  larva.  They  may  also  tend 
to  elucidate  one  of  those  hidden  and  mysterious 
processes  of  nature  by  which  the  exterior  orga- 
nization of  the  queenor  female  inmate  of  the  hive 
is  caused  so  materially  to  differ  from  that  of  the 
so-called  neuter  or  sterile  female,  influenced  as 
it  is  said  to  be  in  its  whole  system  by  the  diffe- 
rent quality  of  the  food  supplied  to  the  larva 
during  the  first  few  hours  of  its  existence. 

According  to  the  investigations  of  the  most 
careful  observers,  Savigny,  Audouin,  Mac- 

*  Considerations,  &c.  p.  48  et  seq. 


leay,  Kirby,  Carus,  Straus-Durckheim,  New- 
man, and  others,  every  segment  of  the  perfect 
insect  is   made  up  of   distinct  parts,  not 
always  separable  from  each  other  or  developed 
to  the  same  extent,  but  existing  primarily  in  all. 
It  is  also  believed  that  the  head  itself  is  formed 
of  two  or  more  segments,  but  the  exact  number 
which  enter  into  its  composition  is  yet  a  ques- 
tion.   So  uncertain  are  the  opinions  held  upon 
this  subject,  that  while  Burmeister  recognizes 
only  two  segments,  Carus  and  Audouin  believe 
there  are  three,  Macleay  and  Newman  four, 
and  Straus-Durckheim,  even  so  many  as  seven. 
These  different  conclusions  of  the  most  able  in- 
vestigators appear  to  have  arisen  chiefly  from  too 
exclusive  examinations  of  the  head  in  perfect 
insects,  without  reference  to  the  corresponding 
parts  in  the  larvae.    It  is  only  by  comparing  the 
distinctly  indicated  parts  of  the  head  in  the  per- 
fect insect  with  similar  ones  in  the  larva  that  we 
can  hope  to  ascertain  the  exact  number  of  seg- 
ments of  which  it  is  composed.    In  the  head  of 
the  perfect  insect  there  ought  to  be  found  some 
traces  of  all  the  segments  which  exist  in  the' 
larva?  of  the  same  species,  and  in  that  of  the 
more  perfectly  developed  larvaa  that  undergo  a 
true  metamorphosis,  there  ought  in  like  manner 
to  be  found  the  rudiments  of  all  the  segments  in 
the  least  perfectly  developed.    Now  the  com- 
mon larva  of  the  Dipterous  insect,  the  maggot 
of  the  flesh-fly,  is  one  of  the  lowest  forms  we 
have  yet  examined,  and  we  have  already  seen 
that  its  head  appears  to  be  formed  of  four,  and 
perhaps  even  of  five  segments.    This  is  the 
greatest  number  yet  noticed  in  the  head  of  the 
larva  of  any  species.    If,  therefore,  we  can 
trace  the  like  number  in  the  head  of  a  perfect 
insect,  we  may  fairly  conclude  that  this  is  the 
normal  number  of  segments  throughout  the 
class.    The  head  of  the  great  water-beetle, 
Hydrous  piceus,  is  remarkably  well-fitted  for 
exemplifying  the  number  of  segments  of  which 
the  head  is  originally  composed,  the  remains 
of  four  of  the  segments  being  distinctly  marked; 
and  it  also  affords  us  a  proof  of  the  correctness 
of  the  opinions  advanced  by  Savigny  and  others, 
that  the  organs  of  manducation  are  the  proper 
articulated  members  of  distinct  segments,  and 
are  perfectly  analogous  to  the  proper  organs  of 
locomotion. 

We  shall  first  describe  the  parts  of  which 
the  head  is  composed,  and  then  endeavour  to 
explain  the  manner  in  which  these  parts  have 
been  developed  from  separate  segments  to  form 
the  perfect  cranium  and  its  appendages.  It 
has  hitherto  been  customary  with  naturalists  to 
designate  the  head  the  first  segment  of  the 
body,  and  as  every  change  in  the  nomenclature 
of  a  distinct  part  ought  always  to  be  avoided, 
unless  positively  required,  through  fear  of 
creating  confusion,  we  shall  not  deviate  on  the 
present  occasion  from  the  established  mode, 
but  when  speaking  of  it  as  a  whole  shall  con- 
sider it  the  first  segment,  while  the  aggregation 
of  segments  of  which  it  is  composed  we  shall 
designate  individually  sub-segments,  distin- 
guishing them  numerically  in  the  order  in 
which  they  appear  to  exist  in  the  earliest  con- 
dition of  the  foetal  larva. 


INSECTA. 


885 


TABLE  OF  THE  PARTS  AND  APPENDAGES  OF  THE  HEAD. 

Fixed  parts  of  the  head — external  surface. 
(a)  occiput,  including  the  foramen  occipitale  and  base  of  the  skull,  and  forming  part  of 

b,  epicranium  vertex,  Kirby  epicrane,  Straus. 

(b  1)  ocelli   stemmata. 

c,  oculi   cornees,  Straus. 

d,  clypeus  anterior  ....  )  nasus,  Kirby   chaperon,  Straus. 

d,*clypeus  posterior... .  S  clypeus,  Fabricius 

n,  gula,  Kirby  piece  basilaire,  Straus. 


e,  labrum 

f,  mandibulje 


Moveable  parts  of  the  head. 


maxilla?, 
into  . . , 


divided 


< 


1,  cardo,  Kirby  branche  transversale,  Straus,  insertio,  Newman 

2,  stipes,  Kirby  piece  dorsale,  Straus;  maxilla,  Newman 

3,  palpifer,  Newman  .  .squame  palpifer,  Straus,  bears 

4,  the  maxillary  palpus,  h. 
5,  lacinia,  Macleay,  Newman;  intermaxillaire,  Straus,  divided  into — 

6,  galea,  Fabricius ;  lobus  superior,  Kirby. 

7,  lobus  inferior,  Kirby. 

8,  unguis,  Kirby. 


i,  labium. 


{ 


ligula,  Newman;  labium,  Macleay. 
k,  the  labial  palpi. 

/,  mentum,  Macleay;  labium,  Newman  \  piece  prebasi- 

m,  submentum  .. stipes,  Macleay ;  insertio,  Newman  S     laire,  Straus. 


12,  lingua,  Newman, . .  .hypopharynx,  Savigny. 


A,  antennae 


r  scapus. 
<  pedicella. 
(.  clavola. 


|  Kir 


by. 


Sub-segments  of  the  head. 
1  st  includes  labrum  and  labium. 


Interior  of  the  head. 


<  os  epipharyngeum, 
"  "  (os  hypopharyngeum  anterius. 

os  hypopharyngeum  posterius,  jr. 
(,  lamina?  orbitales,  w ;  and  ossicula  antenna- 
i£        rum  or  toruli,  r. 
.  sutura  epicranii,  p. 
%  os  transversum,  x. 

5th  includes  epicranium  and  gula  /  laminae  squamosa?,  s  and  v  ;  lames  laterales, 

i  Straus. 

V,  tentorium,  Burmeister,  u ;  arcade,  Straus. 


2d  includes  clypeus  anterior  and  mentum  

3d  includes  clypeus  posterior  and  submentum  . , 
4th,  obsolete,  orbits  and  bones  of  the  antenna;  . 


The  above  table  exhibits  the  whole  of  the 
parts  yet  found  in  the  cranium  in  the  most 
perfect  order  of  Insects,  the  Coleoptera;  but  it 
must  be  remembered  that  many  of  these  parts 
are  less  perfectly  developed  in  the  other  Orders, 
and  in  some  of  the  species  have  not  yet  been 
discovered. 

Commencing  our  examination  of  the  head 
at  the  posterior  part  of  its  upper  surface,  we 
observe  that  the  occiput  ( a,  Jig.  369)  is  that 
portion  of  its  base  which  is  articulated  with 
the  anterior  margins  of  the  prothorax.  It  is 
perforated  by  a  large  foramen,  through  which 
the  organs  of  the  head  are  connected  with 
those  of  the  body.  It  is  very  distinct  in  the 
Hydrous  and  most  Coleoptera,  and  in  some, 
the  StaphylinidiE,  Curabidte,  and  Silphidce,  is 
constricted,  and  extended  backwards  so  as  to 
form  a  complete  neck;  but  in  others,  as  in  the 
Curculionida,  it  is  short  and  hardly  distin- 
guishable from  the  epicranium  (6),  of  which  it 
is  the  continuation  and  posterior  boundary. 


The  epicranium  is  the  whole  of  the  posterior 
and  upper  surface  of  the  head,  bounded  pos- 
teriorly by  the  occiput,  laterally  by  the  corneae 
and  sides  of  the  gula,  and  anteriorly  by  a  tri- 
angular suture  which  extends  from  the  anterior 
margin  of  the  cornea?  to  the  middle  of  the 
head  between  the  eyes,  where  its  apex  unites 
with  a  longitudinal  suture  which  extends  along 
the  median  line  to  the  occiput.  This  trian- 
gular suture  is  a  marked  character  in  the  head 
of  many  insects,  both  in  the  larva  and  perfect 
state,  and  is  of  great  importance  in  deter- 
mining the  number  of  the  sub-segments.  It  is 
very  distinct  in  the  larvae  of  Lepidoptera,  and 
is  as  marked  in  the  Melolonthida  and  the 
Staphylinida:  as  in  the  Hydrous.  In  some  of 
the  beetles  it  is  indistinctly  marked  on  the 
upper  surface,  but  forms  elevated  ridges  on  the 
interior  surface.  This  is  particularly  the  case 
in  the  Hydrous.  In  the  Dyticus  it  is  more 
distinctly  marked  by  a  lighter  colour  of  the 
skull,  while  in  the  common  dung-beetles,  Geo- 


386 


INSECTA. 


Fig.  369. 


External  superior  and  inferior  surface  of  the  head  of 
Hydrous  piceus. 
A,  antenna  ;  a,  occiput ;  b,  epicranium  ;  c,  ocn- 
]i  ;  d,  clypeus  anterior  ;  e,  labrum  ;  /,  mandibles  ; 
g,  maxilla;  h,  its  palpus;  i,  ligula;  h,  labial  pal- 
pus mentum ;  m,  submentum;  n,  gula;  o,  man- 
dibular ridge. 

trupida,  its  existence  is  indicated  by  a  slightly 
elevated  ridge.  This  suture  divides  the  epi- 
cranium from  the  posterior  portion  of  the  cly- 
peus (d),  the  most  conspicuous  portion  of  the 
head.  The  proper  boundaries  of  this  part 
have  been  ascertained  with  tolerable  precision 
in  Coleoptera,  but  do  not  appear  to  have  been 
traced  correctly  in  some  of  the  other  orders, 
particularly  in  Ortlwptera.  The  clypeus  or 
shield,  in  Coleoptera,  is  that  broad  cover  of  the 
anterior  surface  of  the  head,  bounded  poste- 
riorly by  the  epicranium  and  anteriorly  by  the 
labrum,  with  which  it  is  freely  articulated.  It 
is  the  part  called  by  Mr.  Kirby  the  nose,  and 
by  Straus  Durckheim  chaperon.  It  appears 
originally  to  be  formed  of  two  portions,  which 
we  have  called  clypeus  anterior  and  posterior, 
and  which  are  completely  united  in  some  fami- 
lies, as  in  the  Lamellicornes,  without  trace  of 
their  previous  distinction,  but  in  others  with 
slight  traces  of  their  former  separation,  as  in 
Hydrous,  while  both  parts  are  distinctly  articu- 
lated in  some  of  the  Dyticidce,  in  which  its  ante- 
rior portion  appears  to  be  moveable,  and  has  pro- 
bably been  mistaken  for  the  whole  clypeus,  as 
has  been  the  case  in  Orthoptera.*  In  some 
species  the  shield  is  curiously  excavated,  tuber- 
culated,  or  armed  with  a  long  horn,  as  in  Copris, 
Ty  ohaus,  and  Dynastes,  (fig.  333,)  oris  minute 

*  Newman,  p.  9. 


and  inconspicuous  as  in  the  Camthartda.  The 
original  division  of  the  shield  into  two  por- 
tions in  Hydrous  appears  to  be  indicated  by 
two  rough  excavations  situated  between  the 
triangular  suture,  its  posterior  boundary,  and 
the  anterior  lip.  The  labrum  or  upper  lip  (e) 
is  the  most  anterior  portion  of  the  upper  sur- 
face of  the  head,  bounded  only  on  its  posterior 
margin  by  the  clypeus.  It  is  usually  a  narrow 
transverse  piece  which  has  been  confounded  by 
some  writers,  particularly  by  Fabricius,  with 
the  clypeus.  In  some  families,  Scarabaidw 
and  Lucanidtt,  it  is  very  minute,  but,  as  re- 
marked by  Mr.  Newman,*  cannot  be  consi- 
dered to  be  in  any  case  entirely  wanting,  as 
was  supposed  by  Olivier.  In  those  cases  in 
which  it  appears  to  be  absent  it  is  concealed 
beneath  a  largely  developed  clypeus.  In  many 
families  it  is  large  and  projecting,  and  often 
notched,  as  in  the  Carabida  and  Silphida.  It 
is  also  very  distinct  in  the  water-beetles.  It 
forms  the  anterior  boundary  of  the  mouth. 

The  cornea:  constitute  a  great  portion  of  the 
fixed  parts  of  the  head.  The  principal  of  these 
(c),  the  corneas  of  the  true  or  compound  eyes, 
are  situated  on  the  lateral  external  surface  of 
the  cranium,  bounding  the  basilar  piece  below, 
and  the  epicranium  above.  They  are  two  large 
convex  surfaces,  generally  of  a  nearly  circular, 
but  sometimes  of  a  kidney-shaped  form,  divided 
into  a  great  number  of  very  minute  facets,  per- 
fectly distinct  from  each  other,  each  of  which  is 
the  proper  cornea  of  a  distinct  eye.  They  are 
more  or  less  numerous  in  different  insects, 
amounting  in  some  to  no  more  than  fifty  in  each 
compound  eye,  but  in  others  to  so  many  as 
thirty-six  thousand.  Thus  Lyonet  reckoned 
eleven  thousand  three  hundred  in  the  eye  of  the 
goat-moth,  and  Geoffroy  more  than  thirty-six 
thousand  six  hundred  in  the  eye  of  a  butterfly. 
Each  compound  cornea  is  usually  situated  im- 
mediately behind  the  external  angles  of  the 
triangular  or  epicranial  suture,  and  is  more  or 
less  protuberant  in  different  species,  as  in 
Hydrous  and  its  affinities.  This  is  particularly 
the  case  in  the  ground-beetles,  as  noticed  by 
Dalman,f  especially  in  those  which  reside  near 
water  or  in  sandy  situations,  as  the  Cicindelida, 
&c. ;  and,  as  remarked  by  Mr.  Westwood, 
these  protuberant  eyes  occur  mostly  in  insects 
of  rapacious  habits.  But  it  must  further  be 
observed  that  they  occur  also  in  insects  which 
are  not  of  rapacious  habits,  but  require  for 
some  other  purpose  an  extended  field  of  vision. 
This  is  the  case  with  the  males  of  many  species, 
and  most  remarkably  so  in  the  male  of  Lampy- 
ris  noctiluca,  the  common  glow-worm,  in  which 
the  cornea?  cover  almost  the  whole  lateral  and 
under  surface  of  the  head.  This  insect  is  well 
known  to  be  attracted  by  the  light  of  the  female. 
The  like  occurs  in  the  male  of  the  hive-bee, 
and  in  that  of  some  Diptera,  as  in  the  Empida, 
which  seek  their  females,  and  are  constantly 
found  in  copula  connexos  on  the  wing  in  the 
open  air.    Again,  in  the  sun-beetles,  Cetoniida, 

*  Paper  on  the  Nomenclature  of  the  Parts  of  the 
Head  in  Insects,  p.  18. 
i  .Entomologist's  Text-book,  p.  236. 


INSECTA. 


887 


which  live  on  the  pollen  of  flowers,  the  eyes 
are  very  protuberant.  From  these  circumstan- 
ces it  may  be  inferred  that  all  those  insects  in 
which  the  eyes  are  either  protuberant  or  very 
large  are  directed  by  sight  alone  to  some  parti- 
cular object  of  their  search,  whether  this  be  the 
female  of  the  species,  as  with  the  glow-worm, 
&c.  or  the  active  living  prey,  as  with  the  rapa- 
cious beetles ;  and  consequently  in  these  in- 
stances a  more  extended  held  of  vision  is  re- 
quired than  in  those  whose  object  of  search  is 
more  easily  discovered,  or  whose  means  of  sub- 
sistence is  less  precarious.  In  many  Coleop- 
tera  each  eye  is  divided  anteriorly  by  a  process 
of  the  epicranium,  the  canthus,  as  is  particu- 
larly the  case  in  the  Lamellicornes  (fig.  333). 
The  extent  to  which  this  is  developed  in  dif- 
ferent insects  varies  considerably,  and  seems  to 
be  greatest  in  those  species  which  are  constantly 
engaged  in  burrowing.  Thus,  while  it  is  ex- 
tended only  a  little  way  into  the  eye  in  Ceto- 
niidff,  it  is  carried  half  way  across  it  in  Copris, 
and  in  the  female  of  Lucanus  cervus,  but  less 
than  half  in  the  male;  in  the  genera  Atcuchus 
and  Dorcas  more  than  half  way  across  ;  while, 
according  to  Kirby  and  Spence,*  in  another 
genus,  Ryssonatus,  it  completely  divides  the 
eye  into  two.  In  other  instances  the  canthus 
is  not  produced,  but  the  eye  is  encroached 
upon  anteriorly  by  a  portion  of  the  epicranium 
or  by  the  base  of  the  antenna,  which  sometimes, 
as  in  the  Cerumbycidce,  appears  as  if  inserted 
into  the  eye  itself.  In  other  families,  as  in  the 
Gyrinida,  the  middle  of  the  eye  is  excavated 
across  its  whole  surface  by  a  deep  furrow, 
which  gives  the  appearance  of  two  distinct  eyes 
on  each  side  of  the  head.  In  some  insects  the 
eyes  are  entirely  absent,  an  instance  of  which 
occurs  in  one  of  the  Xylophagi,  Annomalus 
terricola,  recently  discovered  by  M.  Robert, 
near  Liege,  and  an  account  of  which  was  read 
before  the  Royal  Academy  of  Sciences  of  Brus- 
sels by  M.  Wesmael,  in  Oct.  1835.  This  in- 
sect, whose  habits  are  believed  to  be  entirely 
subterraneous,  is  without  any  external  organs 
of  vision.f 

The  ocelli,  stemmata,  or  single  eyes,  are 
simple,  convex,  hemispheric  lenses,  varying  in 
number  from  one  to  three.  They  are  always 
situated,  in  those  insects  in  which  they  exist, 
on  the  superior  part  of  the  epicranium,  poste- 
riorly to  the  triangular  suture.  They  are  en- 
tirely absent  in  Hydrous  and  all  Coleoptera 
except  the  Dcrmestida,  in  which  there  is  a 
single  ocellus  situated  on  the  centre  of  the  epi- 
cranium, a  little  posteriorly  to  the  true  eyes;  in 
one  of  the  Paussida,  and  in  some  of  the  smaller 
Brachelytra  ;J  but  they  almost  invariably  exist 
in  some  of  the  other  orders,  as  in  the  Iiymen- 
optera,  Neuroptera,  &c. 

The  under  surface  of  the  head  is  formed  chiefly 
by  the  posterior  and  lateral  parts  of  the  gula 
(fig-  369,  n),  which  unite  with  the  lateral  parts 
of  the  epicranium  and  occiput.  It  is  bounded 
anteriorly  by  an  indistinct  suture,  and  laterally 
by  the  inferior  portions  of  the  cornea;.    In  Me- 

*  Introduction  to  Entomology,  vol.  iii.  p.  602. 
t  Er.  Ent.  Soc.  vol.  ii.  Proceeding,  p,  xii. 
J  Entomologist's  Text-book,  p.  238. 


lolonthida  it  is  of  great  extent,  and  rs  the 
piece  busilaire  of  Straus  Durckhelm.    In  Hy- 
drous it  is  excavated  in  the  middle  line,  on 
each  side  of  which  are  two  elevated  ridges,  the 
remains  of  the  basilar  parts  of  the  mandibles  (o), 
the  proper  appendages  of  the  fifth  sub-segment, 
or  basilar  portion  of  the  head,  with  which  they 
have  become  consolidated.    The  sub-mentum 
(in),  piece  pie-basilaire  of  Straus,  is  the  most 
posterior  of  the  parts  that  form  the  under  faUnus* 
lip.    Straus  Durckheim  and  others  appear  to 
have  considered  this  part  as  a  process  of  the 
immoveable  structure  of  the  head,  with  which 
at  first  it  appears  to  be  firmly  united.  Mr. 
Westwood  remarks,  that  although  it  appears  to 
be  articulated  in  some  beetles,  it  is  immove- 
able, and  forms  part  of  the  under  surface  of 
the  head.*     We  have  but  little  doubt  that 
it  is  a  distinct  piece,  and  is  part  of  the  third 
sub-segment  of  the  head,  however  it  may  be- 
come anchytosed  to  the  gula  by  the  obli- 
teration of  the  fourth  in  some  instances,  or 
be  itself  entirely  obliterated  in  others.  In 
Melolontha  it  is  exceedingly  short,  but  of 
great  width.    In  Hydrous  it  is  very  distinct, 
and  the  maxilla  are  articulated  to  the  skull  on 
each  side  of  its  base,  as  is  the  case  also  in 
Melolontha  and  most  other  instances.    It  is  a 
little  narrower  posteriorly  than  anteriorly,  and 
its  length  is  not  more  than  one-half  its  breadth. 
It  is  articulated  anteriorly  with  the  mentum  (I); 
this  is  a  short  transverse  plate,  in  Hydrous 
somewhat  lunated  on  its  anterior  margin,  rather 
broader  than  long,  but  not  so  short  as  the  sub- 
mentum.    In  Dyticus  it  is  excavated  at  its 
anterior  margin,  the  sides  being  carried  forward 
like  separate  lobes.    In  this  genus  it  forms 
with  the  sub-mentum,  from  which  it  is  sepa- 
rated only  by  a  slight  transverse  articulation,  a 
broad  plate,  rounded  on  its  edges,  and  cover- 
ing nearly  the  whole  of  the  under  surface  of  the 
mouth  ;  in  some  of  the  Staphylinidie  it  is  ex- 
ceedingly short  and  broad,  in  Melolontha  it  is 
nearly  of  a  square  form,  but  its  anterior  mar- 
gin is  acute;  in  Celonia  aurata,  on  the  contrary, 
its  anterior  margin  is  much  wider  than  its  pos- 
terior, or  articulation  with  the  sub-mentum. 
In  Amphimalla  it  is  quadrate  as  in  Melolontha, 
and  forms  with  the  palpiger  a  nearly  square 
plate.  Thepa/piger,  first  described  by  Mr.  New- 
man^ is  not  developed  in  the  lip  of  Hydrous. 
In  those  genera  in  which  it  is  found,  as  in  Dy- 
ticus, it  is  an  articulation  which,  as  its  name 
implies,  bears  the  labial  palpi,  and  is  situated 
between  the  mentum  and  ligula,  of  which  it 
seems  to  be  only  a  portion.    It  is  subject  to 
great  diversity  in  size  and  shape,  and  in  conse- 
quence is  often  confounded  with  the  ligula  itself. 
It  is  said  to  be  very  distinct  in  most  of  the  Ca- 
rabidd;,  and  in  Cychrus  rostratus,  as  remarked 
by  Mr.  Newman,  it  seems  at  first  to  have  entirely 
taken  the  place  of  theligula.  Inthe  Staphylinidte, 
Goerius,  it  is  much  narrower  and  longer  than 
the  mentum,  with  which  it  forms  as  it  were  a 
cone.  In  one  of  the  Endomycliidce,  Lycoperdina 

*  Op.  cit.  1838,  p.  256. 

t  Entomol.  Magazine,  vol.  ii.  p.  82  et  scq.  Also- 
a  Paper  on  the  Nomenclature  of  the  Parts  of  the 
Head  in  Insects,  p.  19. 


888 


INSECTA. 


bovhta,  according  to  the  figure  by  Mr.  Curtis,* 
it  is  a  broad  oval  plate,  much  larger  than  either 
of  the  other  parts  of  the  labium.  This  irre- 
gularity in  its  size  is  very  perplexing  in  examin- 
ing the  parts  of  the  mouth,  since  in  those  cases 
in  which  it  is  developed  to  a  great  extent  the 
ligula  is  often  so  much  reduced  in  size  as  to 
appear  entirely  absent,  and  to  render  it  a  matter 
of  consideration  whether  it  would  not  be  better 
to  consider  the  palpiger  in  all  cases  as  only  the 
inferior  portion  of  the  true  ligula,  since,  in  a 
great  number  of  instances  in  which  the  pal- 
piger is  large,  the  ligula  is  very  small;  and,  as 
in  the  instance  of  Cychrus,  is  formed  only  of 
minute  linear  lobes,  situated  upon  and  almost 
hidden  by  the  palpiger.  The  ligula  («)  is  the 
most  anterior  portion  of  the  under  lip.  It  va- 
ries as  much  in  shape  and  size  as  the  palpiger. 
In  Hydrous  it  is  divided  into  two  lobes  by  a 
slight  fissure  in  its  anterior  margin,  which  is 
membranous,  and  covered,  as  well  as  its  in- 
ternal surface,  with  short  smooth  hairs.  It  is 
the  part  which  properly  represents  the  true  lip, 
its  internal  surface  being  continuous  with  the 
soft  membrane  of  the  mouth.  In  most  of  the 
Geodephagae  it  is  divided  into  three  linear 
lobes,  not  very  unlike  in  their  appearance  to  the 
true  palpi.  This  division  into  lobes  occurs  in 
most  of  the  predaceous  land-beetles.  In  Ci- 
cindelida  the  ligula  is  very  minute,  and  [his  is 
the  case  also  in  some  of  the  Staphylinidee.  In 
the  predatory  water-beetles,  as  Mr.  Newman 
has  observed,  the  ligula  is  of  considerable  size, 
and  this  is  particularly  the  case  in  Hydrous. 

The  mandibles  (fig.  369,/,  jig.  370,  A),  the 
true  organs  of  manducation,  are  two  exceed- 
ingly large  and  strong  arched  jaws  opposed  to 
each  other,  and  sometimes  decussating  like  the 
blades  of  a  pair  of  scissors.  This  is  the  case 
in  the  most  rapacious  insects,  Cicindelida, 
Staph ylinida,  <§c-  In  the  Hydrous  they  do 
not  decussate.  They  are  situated  immediately 
beneath  the  clypeus  and  labrum  on  each  side, 
and  are  connected  by  a  ginglymoid  articulation 
with  the  upper  and  under  surface  of  the  head. 
The  superior  external  condyle  moves  in  the 
articulating  surface  of  the  small  bone  (jig. 
372,  q),  a  little  anterior  to  the  bone  of  the 
antenna?  (?•)  and  the  inferior  external  condyle 
(jig.  370,  3)  in  the  articulating  surface 
(jig.  372,  y)  of  the  os  transversum.  In  this 
insect  their  form  is  somewhat  like  that  of 
a  sickle  or  garden  knife.  They  are  thick 
and  strong  at  their  base,  and  hooked  at  their 
apex,  and  are  armed  with  three  projecting, 
notched,  or  double-pointed  teeth.  The  inter- 
nal margin  of  the  apex  of  the  mandible  is 
excavated  or  grooved,  as  also  are  the  teeth 
along  their  posterior  surface.  The  object  of 
this  has  reference,  probably,  to  the  habit  of 
the  insect,  the  structure  of  the  jaws  being 
somewhat  similar  in  this  respect  to  that  of  the 
jaws  of  the  more  rapacious  Dyticus,  which  is 
said  to  prey  upon  small  fishes  and  water- 
insects.  The  under  surface  of  the  internal 
margin  of  each  mandible  is  covered  with  soft 
villi,  and  there  are  four  condyles  to  each 
mandible.    Those  just  described  perform  the 

*  British  Entomology. 


Fig.  370. 
C  B 


A 


A,  mandible  ;  1,  process  for  2,  extensor  tendon  ; 
3,  process  to  articulate  with  the  inferior  surface  of 
the  cranium;  4  &  5,  flexor  tendon;  6,  internal 
margin  of  jaw;  7,  bifid  teeth. 

B,  under  surface  of  the  maxilla. 

C,  internal  or  upper  surface;  1,  cardo ;  i, 
stipes;  3  &  4,  palpifer;  5,  lacinia ;  6,  galea;  7, 
lobus  inferior  ;  8,  unguis  ;  9,  retractor  maxilla  ; 
10  &  11,  levator  cardo. 

chief  motions ;  the  others  are  the  middle  ex- 
ternal condyle  (1),  which  gives  attachment  to 
the  tendon  of  the  great  extensor  muscle,  and  is 
situated  between  the  superior  and  inferior  con- 
dyles ;  and  the  internal  condyle  {b)  is  situated 
on  the  internal  posterior  margin  of  the  man- 
dible, and  gives  attachment  to  the  flexor 
muscles  of  the  jaw.  The  internal  margin  of 
the  mandible  is  also  rendered  concave,  and 
forms  part  of  the  lateral  boundary  of  the  epi- 
pharynx.  From  the  general  structure  of  the 
mandible  we  at  first  are  lead  to  suppose  that 
the  habits  of  the  insect  are  entirely  carnivorous, 
but  it  is  said  to  subsist  chiefly  upon  aquatic 
plants,  although  it  feeds  with  avidity  on  dead 
larvae  and  aquatic  mollusca.*  In  the  truly 
carnivorous  Coleoptera,  the  Cicindelida,  Cara- 
bida,  and  others,  the  mandibles  are  acutely 
pointed ;  but  in  those  which  feed  upon  vege- 
table matter,  leaves  of  trees,  &c,  they  are 
thick  and  obtusely  dentated,  as  in  Melolon- 
thida:.  In  the  generality  of  species  the  man- 
dibles are  always  strong  dentated  organs,  but 
a  few  exceptions  occur  in  the  Cetoniida,  which 
feed  on  the  pollen  of  flowers,  and  in  the 
Aphodiadte,  which  subsist  on  the  recent  excre- 
ment of  cattle,  in  which  their  margins  are  soft 
and  flexible.  They  are  always  the  most  con- 
spicuous parts  of  the  mouth,  and  differ  from 

*  Westwood,  Introdact.  Entomology,  vol.  i.  p. 
127. 


INSECTA. 


889 


the  lesser  jaws,  maxilla,  in  being  articulated 
both  with  the  upper  and  under  surface  of  the 
head. 

The  maxilla,  or  lesser  jaws  (fig.370,  B,C),  are 
of  very  compound  structure.  They  are  situated 
between  the  mandibles  and  labium,  and  are 
employed  by  the  insect  to  hold  its  food,  and  to 
convey  it  to  the  posterior  part  of  the  mouth.  They 
are  each  formed  of  four  primary  and  three  or 
more  accessory  parts,  when  mostcompletely  deve- 
loped. The  primary  parts  are  the  cardo  or  hinge, 
the  stipes  or  footstalk,  the  palpi  fer,  and  the  lacinia 
or  blade.  The  accessory  parts  are  the  galea  or 
lobus  superior,  the  lobus  inferior,  and  unguis. 
The  cardo  (jig.  370,  B,  C,  1)  is  the  joint  upon 
which  nearly  all  the  motions  of  the  maxilla 
depend.  In  Hydrous  it  is  a  minute  trapezoid 
or  irregularly  triangular  corneous  plate,  with  an 
elongated  curved  process  by  which  it  is  arti- 
culated with  the  os  transversum  on  the  under 
surface  of  the  cranium,  and  over  which  the 
cardo  is  articulated  like  a  hinge.  In  some 
genera,  as  in  Staphylinus,  it  is  more  elongated, 
and  this  is  particularly  the  case  in  Melolontha, 
whence  it  was  called  branche  transvcrsale.  In 
most  instances  it  is  as  it  were  wedged  in 
between  the  sub-mentum  and  mandible.  It  is 
articulated  at  its  anterior  margin  with  the 
second  piece  of  the  maxilla,  the  stipes  (2), 
which  forms  the  outer  surface  of  the  organ, 
being  considered  its  primary  part.  It  is  an 
elongated  corneous  plate,  broadest  at  its  articu- 
lation with  the  cardo.  It  is  approximated 
along  its  anterior  margin  to  the  squama  palpifer 
(3),  a  broad  plate  which  covers  the  superior 
external  surface  of  the  maxilla.  Immediately 
beneath  the  anterior  margin  or  apex  of  the 
squama  is  inserted  the  palpifer  (4),  a  short 
cylindrical  appendage,  which  is  usually  con- 
sidered part  of  the  squama,  the  whole  being 
together  called  the  palpifer.  It  supports  the 
proper  maxillary  or  true  palpus,  which  is  re- 
markable for  its  length  in  the  Hydrous.  The 
lacinia  (5),  sometimes  improperly  called  max- 
illa, forms  the  internal  portion  of  the  organ, 
and,  as  we  shall  hereafter  see,  appears  in  its 
earliest  condition  in  the  embryo  to  constitute  a 
separate  organ  or  appendage,  belonging  to  the 
mentum- — as  the  stipes  appear  to  belong  to  the 
sub-mentum — but  which  in  the  course  of  deve- 
lopment becomes  approximated  to  the  stipes  to 
form  part  of  the  maxilla  of  the  perfect  insect. 
Like  the  stipes,  it  is  a  broad  corneous  plate, 
which  forms  the  greater  portion  of  the  under 
surface  of  the  maxilla,  and  is  articulated  with 
the  cardo  only  by  a  small  portion  of  its  base. 
On  its  upper  surface,  which  forms  a  great  part 
of  the  sides  of  the  mouth,  it  is  soft,  membra- 
nous, and  covered  with  fine  hairs.  It  gives 
origin  at  its  anterior  truncated  extremity  to  the 
accessory  parts  of  the  maxilla,,  the  lobus  supe- 
rior and  inferior.  The  lobus  superior,  or  galea, 
is  a  thick,  double-jointed  organ  (6),  densely 
covered  at  its  anterior  margin  with  stiff  reddish 
hairs.  It  is  articulated  with  the  external  an- 
gle of  the  lacinia,  and  covers  the  lobus  inferior, 
which  is  articulated  with  the  internal  angle, 
and  on  this  account,  more  particularly  in 
Orthoptera,  is  called  the  galea  or  helmet.  It 
is  used  by  this  and  other  insects  as  a  palpus, 


or  feeler,  to  touch  and  convey  food  to  the 
mouth.  The  lobus  inferior  is  a  short  quadrate 
joint  (7),  articulated  with  the  internal  angle 
of  the  lacinia,  of  which  it  forms  the  proper 
continuation.  At  its  superior  extremity  is  a 
minute  articulated  claw  (8),  densely  covered 
on  its  upper  surface  with  long  stiff  hairs,  as  is 
also  the  whole  of  the  internal  margin  of  the  laci- 
nia itself,which  forms  the  lateral  boundary  of  the 
mouth,  and  is  continuous  with  the  soft  lining 
of  the  pharynx.  The  maxillary  palpi  (h)  are 
two  very  long  flexible  organs,  composed  each 
of  four  joints.  The  palpifer,  upon  which  they 
are  situated,  is  a  short  joint  or  tubercle,  in- 
serted at  the  anterior  external  angle  of  the 
maxilla,  between  the  angle  of  the  lacinia  and 
the  plate  which  covers  the  superior  surface  of 
the  maxilla  (3),  and  of  which  it  forms  a  part, 
but  from  which  in  this  insect  it  appears  quite 
distinct.  The  first  joint  of  the  palpus  is  ex- 
ceedingly short,  so  as  to  allow  of  extensive 
motion  to  the  organ  in  every  direction,  while 
the  second  is  much  longer  than  in  most  other 
insects,  and,  when  the  palpus  is  retracted, 
forms  with  the  third  joint  a  distinct  elbow  or 
bend.  The  third  and  fourth  joints  are  also  of 
great  length,  so  that  the  insect  is  enabled  to 
protrude  the  organ  to  a  great  distance.  The 
labial  palpi  (fig.  369,  k)  are  much  shorter  than 
the  maxillary.  The  first  two  joints  are  very 
minute,  the  second  being  partly  hidden  within 
the  first,  but  the  third  and  fourth  are  long  and 
projecting,  but  not  so  long  as  those  of  the 
maxillary  palpi. 

From  all  we  have  been  able  to  observe,  the 
office  of  the  maxilla  appears  to  be  of  a  two- 
fold kind,  and  of  greater  importance  to  the 
insect  than  that  of  the  mandibles  themselves. 
The  chief  office  is  that  of  seizing  and  retaining 
the  food  within  the  mouth ;  and  the  secondary 
that  of  assisting  the  mandibles  in  comminuting 
it  before  it  is  passed  on  to  the  pharynx.  Con- 
sequently all  the  parts  of  the  maxilla  are  sub- 
ject to  great  variation  of  form;  and  in  the  dif- 
ferent tribes  of  Coleoptera,  as  in  the  other 
orders  of  insects,  each  particular  form  is 
adapted  to  the  kind  of  food  on  which  the  in- 
sect subsists.  In  Melolontha,  in  which  the 
four  primary  parts,  the  cardo,  stipes,  palpifer, 
and  lacinia,  were  first  accurately  distinguished 
by  Straus  Durckheim,*  the  maxilla  is  a  thick 
obtuse  organ,  with  the  cardo,  which  is  less 
completely  developed  in  Hydrous  than  in  most 
other  insects,  forming  a  broad  transverse  piece, 
the  stipes  a  short  and  triangular  one,  the  pal- 
pifer also  nearly  triangular,  and  the  lacinia, 
which,  as  Straus  has  remarked,  is  always  con- 
tinuous with  the  pharynx,  nearly  also  of  a  tri- 
angular form,  and  together  constituting  a  thick 
compact  organ,  with  its  inner  angle,  the  lobus 
inferior  in  other  insects,  forming  a  strong  pro- 
jecting inarticulated  tooth,  and  its  external, 
articulated  with  a  short  thick  galea,  armed 
with  three  obtuse  points,  which  probably  serve 
the  office  of  teeth  for  masticating  the  paren- 
chymatous food  of  this  species.    This  form  of 

*  Considerations  Generales  sur  l'Anatomie  Com- 
pare* des  Animaux  Articules,  par  Hercule  Straus- 
Durckheim,  1828,  p.  68,  pi.  i.  fig.  8. 


800 


INSECTA. 


the  maxilla  and  galea  seeri^  more  peculiarly 
adapted  to  the  phytophagous  feeders,  since  in 
the  true  carnivorous  insects,  Cicindelidce,  tiger- 
beetles,  and  the  larger  Carabidtt,  ground-bee- 
tles, the  maxilla  is  more  elongated,  the  inter- 
nal lobe,  or  apex  of  the  lacinia,  is  more  acute, 
and  often  armed  with  a  sharp  hook,  and  the 
galea  assumes  the  form  of  a  distinct  palpus, 
shorter  but  similar  in  appearance  to  the  true 
maxillary  palpus.    This  is  more  manifestly 
the  case  in  the  tiger-beetles,  in  which  the  galea 
is  a  distinctly  double-jointed  palpus,  placed 
on  a  feeler-bearer,  and  the  lacinia  is  armed 
with  along  sharp  hook,  evidently  more  adapted 
for  seizing  and  piercing  its  living  food,  like  the 
canine  teeth  of  carnivorous  quadrupeds,  than 
for  comminuting  it  like  the  strong  tuberculated 
galea  of  the  vegetable-feeding  Melolontha,  or 
the  tuberculated  teeth  of  herbivorous  quadru- 
peds.   The  office  then  of  the  galea,  in  dis- 
tinctly carnivorous  insects,  is  simply  that  of  a 
palpus  or  feeler,  and  in  accordance  with  this 
view  we  find  that   in  the  tiger-beetles  it  is 
longer  than  the  inferior  lobe,  or  hooked  por- 
tion of  the  lacinia.     In  the  ground-beetles 
Mr.  Newman  has  remarked  that  it  is  shorter 
than  the  lacinia,  but,  in  the  generality  of  the 
tribe,  we  have  also  found  it  longer,  as  in  the 
rapacious  Cicindelida,  particularly  in  the  lar- 
ger Carabida,  and  this  is  also  the  case  in  some 
of  the  Harpalida,  particularly  in  one  species, 
Zabrus  gibbus,  which  is  known  to  be  a  vege- 
table feeder.    This  form  of  the  galea,  however, 
seems  more  peculiarly  to  belong  to  the  carni- 
vorous insects,  as  it  is  also  found  in  the  Dyti- 
cida?,  but  not,  as  we  have  seen,  in  the  nearly 
allied  but  far  less  rapacious  HydrophylidtB. 
On  the  other  hand,  in  most  insects  which  feed 
entirely  on  vegetable  matter,  the  galea  is  of  a 
more  obtuse  form,  and  is  less  distinct  from  the 
other  parts  of  the  maxilla  than  in  the  rapacious 
insects.    Thus  in  the  greater  number  of  the 
true  vegetable  feeders  the  galea  is  short,  thick, 
and  densely  covered  with  hair.    This  is  the 
case  not  only  with  the  maxilla?,  but  also  with 
the  mandibles  in  those  insects  whose  food  is 
the  pollen  and   perhaps  also  the  honey  of 
flowers,  as  in  the  Cetoniida,  and  also  in  the 
Geotrupida  and  other  Scarab/Bidx,  which  feed 
upon  soft  decaying  vegetable  matter.    In  the 
Cerambycida,  as  in  the  rare  insect  Monochamus 
sartor,*  in  the  Lepturida,  which  are  found 
upon  umbelliferous  plants  feeding  on  the  pollen 
and  honey ;  and  in  the  stag-beetle,  Lucanus 
cervus,  which  subsists  on  the  sap  that  flows 
from  the  wounded  bark  or  roots  of  trees,  the 
galea  is  always  densely  covered  with  hair,  and 
sometimes  elongated  to  a  considerable  extent, 
as  in  the  stag-beetle.    In  those  species  which 
are   purely  phytophagous,  as  many  of  the 
Galerucidce  and  Chrysomelide,  which  feed  on 
the  parenchymatous  structure  of  leaves,  both 
the  galea  and  lobus  inferior  are  short,  obtuse, 
and  covered  with  stiff  hairs,while  in  theCoccinel- 
lidce  that  very  much  resemble  the  latter  insects, 
but  are  carnivorous  feeders,  the  galea  is  longer 
and  distinctly  jointed,  and  resembles  the  same 
part  in  Hydrous,  being  still  covered  with  hair. 

*  Curtis's  British  Entomology,  pi.  219. 


This  is  also  the  case  in  the  common  me;tl- 
beetle,  Tenebrio  molilor,  which  belongs  to  a 
family  of  less  distinctly  vegetable  feeders. 
From  these  facts  we  are  inclined  to  believe 
that  the  structure  of  the  maxilla  has  much 
closer  connexion  with  the  kind  of  food  and 
habits  of  the  insect  than  that  of  either  the 
labium  or  the  palpi.  The  latter  organs,  how- 
ever, are  subject  to  great  variation  in  the  form 
of  the  terminal  joint,  which  in  some  species  is 
much  dilated  and  shaped  like  a  hatchet,  as  in 
the  common  lady-bird,  Coccinella,  while  in 
others  it  is  acute  or  obtuse.  The  number  of 
joints  is  usually  four,  and  it  has  been  sup- 
posed that  there  are  never  more,  either  in  the 
maxillary  or  the  labial  palpi,  in  any  Coleop- 
terous insect,  but  the  Rev.  Mr.  Kirby*  has 
mentioned  an  instance  in  which  there  appeared 
to  be  an  anomalous  condition  of  the  maxillary 
palpi,  in  this  respect,  in  one  of  the  Geode- 
phaga,  Sericoidia  bembidioides,  K.  In  one  of 
the  palpi  in  this  insect  there  was  a  fifth  joint, 
retractile  within  the  fourth.  Mr.  Kirby  sug- 
gests that  since  the  fifth  joint  was  not  apparent 
in  the  other  palpus,  it  may  perhaps  have  been 
a  false  joint,  produced  by  an  effort  of  nature 
to  repair  a  mutilated  organ,  but  at  the  same 
time  observes  that  if  this  were  the  case  it  is 
the  only  instance  he  has  met  with  in  true  in- 
sects of  the  reproduction  of  a  lost  organ. 

The  antenna  constitute  the  remaining  move- 
able parts  of  the  head  ( fig.  369,  a).  They  are 
occasionally  absent  in  the  larva,  but  never  in 
the  perfect  state  in  any  insects.  They  are  twcr 
jointed  organs,  attached  to  the  head  by  a  dis- 
tinct and  freely  moveable  articulation,  in  some 
insects  near  the  middle  of  the  front  part  of  the 
head,  but  in  Hydrous  and  most  Coleoptera 
on  each  side  immediately  anterior  to  the  cor- 
nea?, at  the  extremity  of  the  epicranial  suture, 
but  never,  so  far  as  we  are  aware,  in  the  epi- 
cranium  itself.  They  are  subject  to  much 
diversity  of  form,  on  which  account  they  have 
been  employed  by  naturalists  as  affording  cha- 
racteristic distinctions  of  different  families. 
They  have  been  divided  into  several  parts,  only 
three  of  which  appear  to  be  generally  applica- 
ble. These  are  the  scapus,  (jig.  371,  m  l),pedi- 
cella  (2),  and  clavola  (3).f  The  scapus,  or 
basial  joint,  is  usually  very  long,  and  often  the 
most  conspicuous  part  of  the  antenna.  It  is 
connected  with  the  tornlus,  or  part  upon  which 
it  moves,  by  means  of  a  ball  and  socket  arti- 
culation, beneath  the  external  margin  of  the 
clypeus.  The  second  joint,  pedicella,  in  Hy- 
drous, as  in  almost  every  species,  is  a  minute 
and  nearly  globular  articulation,  which  allows 
of  the  freest  motion,  and  supports  the  re- 
maining portion  of  the  antenna,  the  clavola, 
which  forms  the  chief  part  of  the  organ,  and 
is  that  which  varies  most  in  general  structure. 
When  each  succeeding  joint  of  the  clavola  is 
gradually  diminished  in  size  from  the  base  to 
the  apex  of  the  organ,  as  in  the  Gryllida, 
Achetida,  and  Blattidtz,  Jig.  342  and  343,  the 
antenna  presents  its  simplest  condition,  and  is 

*  Fauna  Borcali-Araericana,   vol.  iv.  Insects,, 
page  15.  pi.  i.  fig.  2. 

t  Kirby  and  Spence,  p.  515,  et  scq. 


IWSECTA. 


891 


Fig.  371. 


Antennae,  from  Burmeister,  3/eigen,  Paly,  and  Hope. 
M,  antenna  of  Melolontlta  folio;   1,  scapus  ;  2, 
pedicella;  3,  clavus  ;  3*,  the  lamina;. 


called  setaceous  (fig.  371,  A),  but  when,  as  in 
some  of  the  Locustidce,  each  joint  is  much  smal- 
ler than  the  preceding  and  is  angulated  at  its 
sides,  the.  whole  forming  a  sword-like  organ, 
it  is  called  ensiform  (B).  When  all  the  joints 
of  the  clavola  are  of  uniform  thickness,  as  in 
the  Carabidte,  (fig.  329,)  the  antenna  is  said 
to  be  filiform  (fig.  371,  C),  but  when  the  joints 
are  of  equal  size,  but  are  globular  or  rounded, 
as  in  the  Tenebrionida  (Jig.  340),  it  is  called 
jnoniliform  (jig.  371,  D).  When  the  joints, 
as  in  some  of  the  Elateridte,  (fig.  334,)  ap- 
pear like  inverted  triangles,  with  the  inner 
margin  more  produced  than  the  outer,  they 
are  said  to  be  serrated  (fig.  371,  E),  and 
when,  as  in  the  Prionidce,  the  acute  base  of 
each  joint  is  inserted  into  the  middle  of  the 
broad  apex  of  the  joint  behind  it,  imbricated 
(F).  When  every  joint  is  developed  on  one 
side  into  a  spine  or  process,  the  organ  is  said 


to  be  pectinated  (G) ;  and  when  a  spine  or 

process  is  developed  on  each  side  of  the  joints, 
bipectinaled  (&).    In  like  manner  it  is  called 
pli/mose(N )  when  each  joint  producesone  or  more 
rami  which  are  themselves  minutely  pectinated, 
as  in  many  of  the  Bombycidir;  and  when,  as  in 
Hemirr/iipus  fiabellicornis  and  other  Elaterida, 
each  process  from  a  joint  is  flattened,  and  is 
nearly  as  long  as  the  whole  of  the  succeeding 
joints  taken  together,  and  the  whole  form  a 
fan-shaped  organ,  the  antenna  is  called  Jiabel- 
late  (I).    But  when,  as  in  the  true  beetles, 
Pentamera,  the  clavola  ends  in  a  true  capi- 
tulum  or  knob,  it  is  said  to  be  donate  (K),  or 
capitate  (L),  according  as  the  knob  is  gra- 
dually or  suddenly  formed  at  the  extremity  of 
the  organ.    In  Hydrous  the  capitulum  exists 
in  that  form  which  is  designated  perfoliate,  in 
which  the  joints  of  the  club  are  separated  a 
little  from  each  other  by  a  minute  foot-stalk. 
This  form  exists  also  in  the  Necrophori,  and 
in  a  less  degree  in  the  clavated  antenna  of  other 
Silphida.    It  is  in  some  of  the  Lamellicornes, 
the  Scarabceida,  Geotrvpidte,  Dynastida,  and 
Melolonthidx,  that  the  antenna?  reach  a  degree 
of  completeness  which  seems  to  indicate  the 
real  use  of  the  organs.    Thus  in  the  Melolon- 
thidte  (M),  the  capitulum  is  divided  into  seven 
laminae,  which  may  either  be  applied  closely 
together,  or  be  widely  expanded  at  the  plea- 
sure of  the  insect.    In   the  Dynastida  and 
Geotrupida  the  capitulum  is  formed  of  only 
three  laminae,  the  two  outer  ones  being  convex 
externally,  but  flat  on  their  internal  surface, 
while  the  intermediate  one  is  flat  on  both  sur- 
faces, the  flat  surfaces  of  each  being  more 
delicately  organized  than  the  hard  corneous 
exterior.    A  similar  structure  exists  also  in  the 
Scarabteidaz.    When  the  insect  is  in  motion 
the  antennae  are  stretched  out,  and  the  laminae 
are  expanded  to  their  fullest  extent,  but  by 
many  species  are  immediately  retracted  on  the 
occurrence  of  any  loud  or  sudden  noise. 

These  are  the  usual  forms  of  the  antennae, 
but  in  some  species  they  are  subject  to  much 
greater  variation.  Thus,  in  the  remarkable 
order  Strepsiptera  ( fig.  347),  each  antenna  has 
a  distinct  lobe  at  its  base.  This  is  also  the 
case  in  some  of  the  Muscida  (N),  in  which  the 
filamentous  portion  of  the  antenna  represents 
the  true  clavola,  and  the  club-shaped  portion 
of  the  organ  is  simply  an  appendage.  A  simi- 
lar deviation  from  the  usual  structure  occurs  in 
some  Coleoptera,more  particularly  in  the  smal- 
ler water-beetles.  Thus,  in  the  Gyrinidit,  the 
true  pcdicella  is  developed  into  a  large  ear- 
shaped  cup,  which  nearly  covers  the  clavola. 
In  another  insect,  Globaria  Leachii,  Latr. 
very  beautifully  figured  in  the  recent  work 
of  the  Rev.  F.  W.  Hope,*  the  pedicella, 
(O,  2)  instead  of  being  a  small  rounded  joint, 
is  elongated  like  the  scapus  (1),  while  the  cla- 
vola (3)  ends  in  a  large  capitulum,  attached 
laterally  to  the  base  of  the  fifth  joint  and  di- 
rected backwards.  These  are  a  few  of  the 
variations  which  occur  in  the  form  of  these 

*  The  Coleouterist's  Manual,  part  ii.  tab. 
tig.  6.  1U38. 


892 


INSECTA. 


curious  organs,  the  necessity  of  which  it  is 
difficult  to  understand. 

The  function  of  the  antenna  has  been  a 
Subject  of  much  dispute  amongst  naturalists, 
some  contending  that  it  is  simply  that  of  feel- 
ing, others  that  of  smelling,  others  again  that 
of  hearing,  and  lastly  others  that  of  a  sixth 
sense  unknown  to  vertebrata.  Our  own  ob- 
servations lead  us  most  decidedly  to  the  con- 
clusion that  the  primary  function  of  the  an- 
tennae is  that  of  hearing  or  feeling  the  vibra- 
tions of  the  atmosphere,  while  an  additional 
function  possessed  by  the  antenna?  of  many 
insects  is  that  of  common  feeling  or  touch. 
We  have  endeavoured  to  support  this  opinion 
by  facts  and  experiments  detailed  in  a  paper 
on  the  use  of  the  antenna?,  which  was  read 
before  the  Entomological  Society  of  London 
in  the  beginning  of  1838,  but  which  has  not 
yet  been  printed.  First  as  regards  the  employ- 
ment of  the  antenna?  as  olfactory  organs,  there 
seems  in  their  anatomical  structure  the  most 
decided  evidence  that  they  cannot  be  designed 
for  such  purpose.  In  every  instance  in  verte- 
brata, the  faculty  of  smelling  is  situated  in  a 
delicate  mucous  or  soft  surface,  and  in  no 
animal  that  we  are  aware  of  has  it  ever  been 
found  to  reside  in  a  dry  horny  covering,  or  in 
a  tense  membranous  structure,  while,  on  the 
contrary,  that  of  hearing  is  constantly  depen- 
dent upon  an  elastic  membrane,  or  other  part 
sufficiently  delicate  to  be  affected  by  the  vibra- 
tions of  the  atmosphere.  If  therefore  the  sense 
of  smelling  be  dependent,  as  it  appears  to  be, 
upon  a  moist  or  lubricated  surface,  it  cannot 
reside  in  the  antenna?,  since  the  exterior  sur- 
face of  these  organs  is  in  every  instance  formed 
of  a  dry  hardened  covering.  On  the  other 
banc,  if  the  perception  of  sound  be  depen- 
dent upon  the  elasticity  of  a  part,  and  its  capa- 
bility of  being  affected  by  the  vibrations  of  the 
air,  the  structure  of  the  antennae  is  in  no  in- 
stance unadapted  for  the  performance  of  this 
function.  It  seems  improbable  that  the  office 
of  the  antenna?  is  simply  that  of  touching  or 
feeling  other  objects,  by  direct  contact,  as  sup- 
posed by  some  naturalists,  from  the  circum- 
stance that  in  certain  insects  these  organs  are 
much  too  short  to  be  so  employed,  being  in 
many  species,  as  in  the  Libellulida  and  Ciea- 
diid<e  (Jig.  353),  shorter  than  the  head  itself. 
But  that  they  are  so  employed  by  some  insects 
is  indisputable,  particularly  by  the  Blattida, 
Gryllidce,  and  most  of  the  Hymenoptera. 
The  Gryllida?,  when  sipping  water  from  the 
channelled  surface  of  a  moistened  leaf,  con- 
stantly feel  about  with  the  antenna? ;  and  the 
honey-bee,  when  constructing  its  cells,  ascer- 
tains their  proper  direction  and  size  by  means 
of  the  extremities  of  these  organs,  while  the 
same  insect,  when  evidently  affected  by  sounds, 
keeps  them  motionless  in  one  direction,  as  if 
in  the  act  of  listening.  Another  circumstance 
which  favours  the  opinion  that  they  are  audi- 
tory organs  is  their  greater  development  in  the 
males  of  some  species  than  in  the  females,  as 
in  the  bipectinated  antenna?  of  many  moths, 
and  the  lamellated  ones  of  the  Melolonthidts. 
The   structure  well  known  to  exist  in  the 


Crustacea,*  the  bony  tubercle  covered  exter- 
nally by  a  tense  membrane,  and  communi- 
cating internally  with  a  membranous  vesicle, 
situated  at  the  base  of  the  antennae,  sufficiently 
proves  that  in  those  animals  the  antenna?  are  or- 
gans of  hearing,  and  is  not  an  inadequate  reason 
for  regarding  them  as  ministering  to  the  same 
function  in  insects.  But  the  fact  of  the  ex- 
istence of  a  small  circular  space  discovered  by 
Treviranus,  at  the  base  of  each  antenna  in  the 
Blattida,  (jig.  373,  t)  which  are  noted  for 
extreme  acuteness  of  hearing,  and  which  space, 
as  in  Crustacea,  is  covered  by  a  membrane,  is 
an  additional  reason  for  considering  the  func- 
tion of  the  antennae  in  insects  analogous  to 
that  of  the  corresponding  organs  in  those 
animals.  Thus  then  almost  every  circumstance 
connected  with  the  antennae  leads  us  to  the 
conclusion  that  these  are  the  proper  organs  of 
hearing,  while  their  occasional  employment  as 
factors  or  cerebral  feelers  is  not  incompatible 
with  the  exercise  of  that  function,  hearing  be- 
ing in  reality  only  a  more  exquisite  sense  of 
feeling. 

Fig.  372. 


e 


Interior  of  the  upper  and  under  surface  of  the 
head  of  Hydrous, 
d,  clypeus ;  e,  labrum ;  g,  maxilla;  h,  its  pal- 
pus ;  i,  labium  ;  k,  labial  palpus  ;  p,  sutura  epi- 
cranii ;  q,  cotyloid  cavity  ;  r,  torulus;  s,  v,  lamina 
squamosa?;  t,  lamina?  posteriores  ;  u,  tentorium; 
to,  lamina?  orbitales  ;  x,  os  transversum ;  y,  arti- 
culating cavity  for  the  mandible  ;  x,  os  hypopha- 
ryngeum. 

Internal  parts  of  the  head. — On  the  interior 
surface  of  the  superior  portion  of  the  cranium 
of  Hydrous  piceus  (fig.  372),  the  insect  we  have 
selected  for  our  purpose,  is  a  thick  horny  ridge 
C p),  extending  along  the  middle  line  from  the 

*  See  vol.  i.  p.  768,  art.  Crustacea. 


INSECTA. 


893 


occipital  foramen  to  about  midway  between  the 
corneae,  where  it  becomes  much  thickened  and 
expanded,  and  then  divides  into  two  portions, 
which  pass  forwards  and  outwards  in  a  dia- 
gonal direction,  to  the  anterior  margin  of  each 
cornea.  These  ridges  on  the  internal  surface 
exactly  correspond  to  the  faint  indication  of  the 
epicranial  suture  on  the  external.  They  serve 
for  the  attachment  of  muscles,  and  divide  the 
epicranium  from  the  clypeus  posterior.  At 
the  external  angles  of  these  ridges,  immediately 
anterior  to  the  cornea;,  are  two  articulating  apo- 
physes, the  most  external  of  which,  the  torulus 
(r),  is  smooth  and  rounded  on  its  anterior  sur- 
face, and  articulates  with  the  broad  concave 
extremity  of  the  scapus]  or  basial  joint  of  the 
'n-  antennae,  and  the  external  one  (g),  (cavite  coty- 
loid, Straus,)  is  smooth,  rounded,  and  con- 
stricted in  its  middle,  and  articulates  anteriorly 
with  the  superior  external  condyle  of  the  man- 
dible, and  posteriorly  with  a  process  of  the 
lamina,  squamosa,  (s),  which  support  and  pro- 
tect the  brain,  and  are  united  with  other  la- 
mina; (y)  (lames  laterales,  Straus,)  which 
arise  from  the  inferior  surface  of  the  cranium. 
The  torulus  (r)  is  attached  externally  to  the 
most  anterior  portion  of  a  thin  broad  lamina, 
the  orbital  plate  (w),  which  extends  backwards 
to  the  posterior  angle  of  the  cornea,  in  an 
arched  direction,  separating  the  cavity  of  the 
orbit  from  the  interior  of  the  cranium,  with 
which  it  communicates  only  by  means  of  a 
round  foramen  for  the  passage  of  the  large 
optic  nerve  and  its  trachea;.  The  superior  half 
of  this  plate  consequently  belongs  to  the  epi- 
cranial, and  the  inferior  to  the  basilar  portion 
of  the  skull.  Immediately  anterior  to  the  epi- 
cranial suture  is  situated  the  clypeus  (d),  the 
middle  portion  of  which  is  smootli  and  slightly 
concave,  and  forms  the  covering  of  the  ante- 
rior part  of  the  head.  On  either  side  it  has  a 
smooth  broad  inflected  margin,  which  is  not 
included  within  the  interior  region  of  the  head. 
At  the  anterior  margin  of  the  clypeus  is  arti- 
culated the  freely  moveable  labrum  (e),  the 
under  surface  of  which  is  smooth  and  shining, 
and  gives  no  attachment  to  muscles,  excepting 
along  its  posterior  margin.  The  ridge  of  the 
epicranial  suture  is  developed  to  a  greater  ex- 
tent in  the  head  of  Hydrous  than  in  any  other 
species  we  have  yet  examined.  Its  perfect 
correspondence  with  the  faint  indication  of  the 
suture  on  the  exterior  of  the  head  clearly  in- 
dicates the  boundary  of  the  epicranium,  and  is 
of  very  great  importance,  as  we  shall  hereafter 
see,  in  enabling  us  to  determine  the  number 
of  segments  of  which  the  head  is  composed. 
This  suture  exists  in  every  species  we  have 
examined,  more  or  less  developed  in  different 
individuals.  Its  existence  appears  to  have 
been  entirely  overlooked  by  Straus-Durckheim 
in  the  head  of  Melolontha,  in  which,  indeed, 
it  is  almost  obliterated  externally,  but  when 
the  cranium  is  well  cleansed,  and  then  ex- 
amined by  means  of  transmitted  light,  a  trace 
of  it  may  still  be  observed,  and  its  situation 
internally  is  indicated  by  a  shallow  triangular 
furrow,  which  extends  backwards  from  the 
anterior  portion  of  each  orbital  plate  to  within 


a  short  distance  of  the  occipital  foramen  in  the 
middle  line,  the  longitudinal  portion  being 
exceedingly  short.  But  in  the  larva  of  the 
same  insect  the  suture  is  very  distinct  on 
the  exterior  of  the  epicranium,  and  the  ridges 
corresponding  to  the  suture  are  developed  on 
the  interior.  Anterior  to  this  suture  in  the 
same  larva  is  a  triangular  piece,  which  is 
bounded  in  front  by  a  freely  articulating  plate, 
the  anterior  clypeus.  It  is  the  part  correspond- 
ing to  this,  and  which  is  consolidated  witli  the 
true  clypeus  in  the  head  of  Hydrous,  as  in- 
dicated by  the  diagonal  depressions  before 
noticed  on  the  external  surface  of  the  head, 
which  we  shall  distinguish  in  all  insects  as  the 
clypeus  anterior. 

It  will  thus  be  found  that  in  some  insects 
the  clypeus  anterior  and  posterior  have  hitherto 
been  confounded  under  one  name,  and  in 
others  the  clypeus  posterior  and  epicranium.. 
We  believe,  however,  that  these  are  distinct 
parts  in  all  insects,  but  are  less  readily  distin- 
guished in  some  than  in  others.  The  upper 
surface  of  the  head  is  thus  shewn  to  be  formed 
of  at  least  four  clearly  indicated  portions,  both 
in  the  larva  and  perfect  insect.  In  the  larva  of 
melolontha  there  is  also  a  slight  indication  of  a 
fifth  segment,  of  which  the  antenna;,  or  ante- 
rior prolongations  of  the  spinal  columns,  are  in 
reality  the  proper  appendages.  The  indication 
of  this  segment  exists  in  a  triangular  line, 
parallel  with,  but  a  little  anterior  to,  the  suture 
behind  the  clypeus  posterior,  and  in  the  space 
included  between  it  and  the  epicranial  suture 
the  antenna;  seem  to  be  inserted.  But  al- 
though we  believe  in  the  existence  of  the  fifth 
segment  in  all  insects,  it  must  be  acknowledged 
that  it  is  not  easily  demonstrated.  Four  seg- 
ments are,  however,  readily  detected,  yet  in 
some  species  one  of  these  has  almost  disap- 
peared. Thus  in  Geotrupes  stercorarius,  the 
epicranial  suture  has  become  very  indistinct  on 
the  upper  surface  of  the  head,  and  the  ridges 
are  entirely  absent  on  the  interior,  as  in  melo- 
lontha, while  the  clypeus  posterior  exists  only 
as  a  narrow  triangular  space,  bounded  by  the 
suture  posteriorly,  and  anteriorly  by  a  ridge  cor- 
responding to  the  boundary  of  the  proper  an- 
terior clypeus  on  the  exterior  of  the  head  ;  the 
labrum  also,  as  in  all  insects,  being  quite  dis- 
tinct. In  Lucanus  cervus,  in  which  the  head 
has  reached  its  maximum  of  development,  and 
is  much  broader  than  the  pro-thorax,  there  is  no 
indication  whatever  of  the  triangular  suture  in 
the  male,  all  the  parts  of  the  head  being  firmly 
consolidated  together.  But  in  the  female  there 
is  a  faint  depression  internally,  as  in  melolon- 
tha, and  the  trace  of  a  corresponding  line  is 
apparent  in  some  specimens  externally.  In 
some  specimens  of  Melde  cicatricosus  there  is  a 
distinct  indication  of  the  suture  externally,  ex- 
tending from  the  occipital  foramen  to  near  the 
middle  line  between  the  eyes,  while  internally 
the  ridge  is  distinctly  elevated ;  but  we  have 
not  been  able  to  trace  the  clypeus  posterior, 
which  may  be  supposed  to  have  merged  in  the 
largely  developed  epicranium.  In  Blaps  mor- 
tisaga  the  epicranial  suture  is  usually  distinct 
on  the  upper  surface  of  the  head,  posterior  to 


804 


INSECTA. 


the  cornete,  but  the  ridge  is  absent,  while  the 
transverse  ridges  between  the  two  portions  of 
the  clypeus  are  distinct,  and  also  their  corres- 
ponding sutures  on  the  exterior.  On  the  other 
hand,  in  the  large  Buprestis  chrysis,  the  longi- 
tudinal portion  of  the  epicranial  suture  is  very 
distinctly  marked  on  the  upper  surface,  and  ex- 
tends as  far  forward  as  the  middle  between  the 
cornea,  while  internally  the  ridge  is  so  largely 
■developed  that  it  extends  downwards  into  the 
cavity  of  the  head,  like  the  ossified  falx  in  the 
head  of  some  Carnivorous  Mammalia,  partially 
dividing  the  posterior  region  of  the  head  into 
two  halves.  But  the  clypeus  anterior  and  pos- 
terior are  so  solidified  together,  and  united  with 
the  epicranium,  that  they  are  not  easily  distin- 
guished. This  is  also  the  case  in  the  rapacious 
ground-beetles,  Cicindelidce,  in  which  all  the 
parts  of  the  cranium  are  completely  united,  and 
the  true  clypeus  is  reduced  to  a  narrow  trans- 
verse plate,  with  which  the  labrum  is  freely  ar- 
ticulated. But  in  the  rapacious  water-beetle, 
Dyticus  niarginalis,  although  the  ridge  of  the 
•epicranial  suture  is  wanting,  as  in  Cicindelida, 
the  suture  itself  is  remarkably  distinct,  and  the 
anterior  and  posterior  clypeus  are  well  marked, 
and  are  very  clearly  seen  owing  to  their  thin- 
ness and  translucency,  when  examined  by 
transmitted  light. 

The  inferior  surface  of  the  head  affords  us 
■equal  reason  with  the  superior,  for  believing 
that  this  part  of  the  insect  is  formed  of  an  ag- 
gregation of  several  segments.  We  shall  ex- 
amine them  more  particularly  when  speaking 
of  its  development.  On  its  interior  surface 
are  parts  which  tend  much  to  confirm  the  opi- 
nion. In  Hydrous  piceus  on  each  side  of  the 
occipital  foramen  there  arises  a  strong  bony 
plate,  lamina  posterior  (t),  which,  bending  a 
little  towards  the  median  line,  extends  across 
the  basilar  portion  of  the  skull,  as  far  as  the  os 
transversum  (j),  with  which  it  is  united.  At  a 
short  distance  from  the  occipital  foramen  the 
lamina  of  one  side  is  connected  with  its  fellow 
of  the  opposite  by  a  narrow  bony  arch  (u), 
which  has  been  called  by  Straus  ('arcade,  and 
by  Burmeister,  who  has  described  it  in  Dyticus, 
the  tentorium.  The  two  lamina  beyond  this 
are  expanded  upwards  and  laterally,  and  uniting 
anteriorly  by  a  thin  process  form  a  cradle,  or 
bed,  which,  as  Straus  and  Burmeister  have  re- 
marked, supports  the  first  suboesophageal  gan- 
glion, while  the  two  lamina  posteriores  inclose 
between  them,  as  in  a  canal,  the  anterior  por- 
tion of  the  spinal  cord,  which  passes  under 
the  tentorium  in  its  exit  from  the  cranium 
through  the  occipital  foramen.  Each  of  these 
expanded  portions  of  the  lamina  are  united  hy 
their  superior  angles  with  a  narrow  process  (s), 
which  articulates,  as  before  noticed,  with  one 
of  the  apophyses  of  the  upper  surface  or  vault 
of  the  cranium.  The  orbital  plates  (w)  above 
described  are  continued  around  the  margin  of 
the  cornea,  and  form  the  inferior  lateral  boun- 
dary of  the  basilar  portion  of  the  cranium. 
Between  the  anterior  margins  of  the  cornea, 
extending  across  and  dividing  the  basilar 
part  of  the  skull  from  the  sub-mentum,  is  a 
thick  elevated  ridge,  the  os  transversum  (x). 


On  its  anterior  border  the  os  transversum  is 
connected  with  a  minute  bony  ridge,  which  ex- 
tends forwards  on  each  side  of  the  sub-mentum, 
and  it  has  also  two  articulating  surfaces.  The 
first  and  most  internal  of  these  (,r)  is  situated 
close  to  the  base  of  the  sub-mentum,  and  is  that 
with  which  the  hinge  of  the  maxilla  is  articu- 
lated. The  second  is  situated  more  externally, 
between  this  and  the  margin  of  the  cornea.  It 
is  a  deep  smooth  cotyloid  cavity  (y),  which  re- 
ceives the  external  inferior  angle  of  the  man- 
dible, and  is  separated  from  the  articulation 
for  the  hinge  of  the  maxilla  by  an  elevated 
tubercle.  Externally  the  base  of  the  skull  is 
connected  only  by  an  indistinct  suture  with  a 
quadrate  plate,  the  sub-mentum,  which  was  sup- 
posed by  Straus-Durckheim  to  form  a  process 
only  of  the  basilar  piece  in  melolontha,  and 
was  called  by  him  the  pre-basilaire.  We  have 
already  seen  that  it  is  part  of  a  distinct  segment, 
and  seems  to  correspond  to  the  clypeus  poste- 
rior of  the  upper  surface.  At  the  anterior  mar- 
gin of  the  sub-mentum,  or  rather  extending 
backwards  upon  that  segment  from  the  men- 
turn,  are  two  broad  diverging  lamina  (z), 
which  support  the  fleshy  pharynx  and  tongue, 
in  which  respect  they  are  similar  in  office  to 
the  proper  hyoid  bones  of  vertebrata.  They 
serve  as  means  of  attachment  for  some  of  the 
muscles  of  the  pharynx,  and  are  connected 
with  similar  lamina  that  cover  the  upper  sur- 
face of  the  pharynx,  and  seem  to  be  connected 
with  the  clypeus,  as  in  the  Lucanus  cervus. 
The  mcntum,  like  the  sub-mentum,  to  which  it 
is  attached,  is  broad,  quadrate,  and  supports 
the  diverging  lamina  which  form  the  floor  of 
the  mouth,  and  it  also  affords  an  attachment  for 
some  of  the  muscles  of  the  tongue  and  labial 
palpi.  The  ligula,  or  most  anterior  portion  of 
the  labium,  is  densely  covered  on  its  upper 
surface  with  hairs.  It  is  divided  in  the  median 
line  into  two  halves,  which,  when  developed  to 
a  much  greater  extent,  as  in  some  other  insects, 
take  the  name  of  paraglossa. 

The  general  structure  of  these  parts  is  similar 
in  most  Coleoptera,  but  in  some  species  there 
is  considerable  variation  of  form  and  relative 
size,  owing  to  the  greater  development  of  one 
part  than  of  another.  Thus  in  Lucanus  cervus, 
(Jig.388,)  in  which  the  whole  head  is  developed 
to  its  greatest  extent,  and  the  epicranial  and 
basilar  regions,  with  the  mandibles  (,/'),  have 
very  far  exceeded  their  usual  proportions,  the 
labrum  is  very  minute,  and  soldered  to  the 
clypeus  (d),  and  the  maxilla  (g)  are  reduced  to 
small  palpiform  organs.  Internally,  the  pos- 
terior lamina  (t)  do  not  extend  forward  to  an  os 
transversum,  but  are  short,  strong,  triangular 
plates,  which,  instead  of  being  connected,  as  in 
Hydrous  and  Melolontha,  by  an  arcade,  or  ten- 
torium (w),  support  a  double  ring,  or  annulus, 
like  the  ring  of  a  vertebra,  through  which  the 
nervous  cord  passes  before  it  arrives  at  the 
occipital  foramen.  In  Geotrupes  stercorurius 
there  is  a  like  annular  form  of  the  same  parts, 
but  the  (amine  squamosa,  which  are  absent  in 
Lucanus,  are  thick  and  strong,  and  form  a 
complete  cradle  for  the  supra-cesophageal 
ganglion.    In  like  manner  a  similar  change  in 


INSECTA. 


895 


the  form  and  relative  size  of  parts  of  the  head  oc- 
curs in  the  hog-beetles, Curculionida  {Jig.  337), 
in  which  the  head  is  elongated  forwards,  and 
the  mouth  is  situated  at  the  extremity  of  a  long 
rostrum  or  beak.    This  is  occasioned  by  the 
narrowing  and  extension  forwards  of  the  clypei, 
and  the  parts  corresponding  to  them,  the  men- 
turn  and  sub-mentum.    This  change  is  carried 
to  such  an  extent  in  some  species,  as  in  Liparis 
Germanus,  that  the  antennas  are  also  carried  for- 
wards, and  appear  as  if  situated  at  the  sides  of 
the  mouth.    That  this  is  the  manner  in  which 
the  change  of  form  is  effected  is  proved  by  the 
circumstance,  that  the  basilar  and  epicranial 
regions  in  this  insect  do  not  exceed  a  fair  pro- 
portion, as  compared  with  other  insects;  while 
the  triangular  suture,  which  always  divides  the 
epicranium  from  the  posterior  clypeus,  exists  in 
its  usual  situation  on  the  part   between  the 
eyes;  and  the  labrum,  which  is  very  distinct,  is 
freely  articulated  with  the  anterior  margin  of 
the  clypeus.    The  effect  of  this  elongation  of 
some  parts  of  the  head  and  mouth  is  the  neces- 
sarily small  size  of  others,  and  consequently  we 
find  that  the  mandibles,  which  are  so  enor- 
mously large  in  Luc-anus,  are  reduced  almost  to 
their  minimum  in  the  Curculio ;  because,  al- 
though the  elongated  form  of  the  head  is  admi- 
rably adapted  to  the  habits  of  the  insect,  in 
boring  deeply  into  hard  substances,  it  is  insuffi- 
cient for  the  support  of  large  and  powerful 
organs,  and  its  extent  of  surface  is  too  limited 
to  afford  adequate  room  for  the  muscles  neces- 
sary for  their  employment.    Wherever  large 
and  powerful  organs  exist,  the  parts  to  which 
they  are  attached  are  enlarged  in  like  manner. 
Thus  we  invariably  find  that  in  those  insects  in 
which  the  mandibles  are  large,  the  whole  head 
is  either  short  and  wide,  or  its  posterior  por- 
tions, the  basilar  and  epicranial  regions,  to 
which  the  muscles  of  the  mandibles  are  at- 
tached, greatly  exceed  those  of  the  anterior. 

The  parts  observed  in  the  head  in  Coleop- 
tera  are  equally  apparent  in  Orthoptera.  In 
this  order  the  head  is  placed  vertically  on  the 
pro-thorax,  without  any  constricted  portion  or 
neck,  so  that  the  extent  of  the  occipital  region 
is  greatly  reduced.    The  epicranium  in  some 
species,  Locustidte,  c)c.  is  broad  behind,  but 
narrowed  in  front,  where  it  is  bounded,  as  in 
other  insects,  by  the  clypeus  posterior,  and  la- 
terally by  the  cornea;  and  sides  of  the  head,  of 
which  it  forms  a  part.    In  this  order  the 
ocelli,  or  single  corneas,  which  are  found  only 
in  a  few  solitary  instances  in  Coleoptera,  exist 
in  most  of  the  families.    They  are  situated  in 
the  anterior  portion  of  the  epicranium,  and 
form  part  of  its  surface,  whether  placed  on  the 
vertical  portion  of  the  head,  or  more  anteriorly 
near  the  clypeus.    In  the  osculant  family, 
Blattida,    the   epicranium    is  exceedingly 
shortened,  but  retains  along  its  vertex  a  trace  of 
the  epicranial  suture,  which  is  scarcely  ever 
absent  in  the  insects  of  this  order.    It  is  very 
distinct  in  the  common  house-cricket  and  mole- 
cricket,  Aclietida  (Jig-  342),  in  the  Gryllidie 
and  Locust  idee.    In  the  mole-cricket  it  some- 
times appears  as  if  wholly  obliterated,  but  is 
always  seen  in  the  pupa  if  care  be  taken  to 


remove  the  down  with  which  it  is  sometimes 
covered.  Its  apex  is  situated  in  the  middle 
line  between  the  ocelli,  and  on  each  side  it 
passes  down  to  the  insertion  of  the  antenna?.  It 
is  in  this  order  that  the  suture  is  particularly 
useful  in  indicating  the  boundary  of  the  pos- 
terior clypeus,  the  extent  of  which  in  Orthop- 
tera appears  hitherto  to  have  been  overlooked. 


Fig.  373. 


Head  of  Blatta  Americana. 

A,  antenna  ;  t>  tympanum  ;  f  t>  socket  for  the  an- 
tenna, covered  with  membrane ;  dd,  clypeus, 
anterior  and  posterior;  *,  lingua;  »**,  paraglossae. 
(  Other  letters  and  Jiyures  as  in  Hydrous. ) 

In  the  epicranium  of  Blatta  (Jig.  373),  the 
suture  is  almost  obliterated,  being  only  disco- 
verable by  aid  of  the  microscope,  but  on  careful 
inspection  it  is  seen  to  end  at  a  point  opposite 
to  the  middle  of  the  superior  portion  of  the 
corneas,  where  it  forms  the  apex  of  the  triangle, 
which  enters,  on  each  side,  the  anterior  margin 
of  a  circular  space  covered  with  a  tense  mem- 
brane, the  tympanum  (f),  which  is  situated,  as 
observed  by  Treviranus,  a  little  behind  the  in- 
sertion of  the  antennas.    These  organs  are  also 
inserted  in  a  rounded  space  covered  by  a  mem- 
brane.   From  these  points  the  suture  becomes 
obliterated,  but  seems  to  pass  in  the  direction 
of  the  anterior  boundary  of  the  corneas  to  the 
base  of  the  mandibles.    The  clypeus  posterior 
(d)  thus  appears  to  form  the  greater  portion  of 
the  front  or  face  of  the  insect,  and  is  united  by 
a  transverse  freely  articulating  membrane,  ex- 
tending across  from  the  base  of  each  mandible 
with  a  short  transverse  plate,  the  clypeus  ante- 
rior (d ),  which  has  hitherto  been  looked  upon 
as  the  true  clypeus.    In  the  common  green 
grasshopper,  Acrida  viridissima,  the  boundary 
of  the  posterior  clypeus  is  at  the  most  anterior 
part  of  the  head  immediately  between  the  an- 
tennae, the  suture  extending,  as  in  other  in- 
sects, to  their  base.    The  clypeus  anterior  is  a 
short  transverse  moveable  plate,  and  is  articu- 
lated with  the  labrum  (e),  which  is  also  short, 
transverse,  and  freely  moveable  upon  the  cly- 
peus anterior.    This  moveable  condition  of  the 
anterior  clypeus  and  lip  has  not  a  little  puzzled 
entomologists.    Mr.  Newman*  has  remarked 
that  "  the  lip  and  shield  move  simultaneously 

*  Op.  cit.  p.  9. 


896 


INSECTA. 


with  the  mandibles  in  mastication,"  and  that 
"  this  is  a  departure  from  a  general  law  of 
nature,  and  its  occurrence  is  well  worth  re- 
marking; as  the  motion  of  the  shield  might  in- 
duce an  observer  to  suppose  it  the  lip,  which 
would  consequently  become  a  new  and  super- 
numerary elementary  part."  Thus,  then,  the 
motion  of  this  part  in  Orthoptera  is  considered 
as  an  anomalous  condition,  but  the  same  thing 
occurs  in  Coleoptera.  In  Dyticida,  the  cly- 
peus  is  freely  moveable,  as  well  as  the  labrum, 
and  probably  this  mobility  has  reference  to  the 
rapacious  habits  of  the  insects. 

The  inferior  surface  of  the  head  in  Orthoptera 
varies  a  little  from  the  type  of  the  Coleoptera, 
although  it  is  formed,  as  in  that  order,  of  four 
distinct  parts.  The  gtila,  or  basilar  region  ( m), 
which  includes  part  of  the  occipital  foramen,  is 
a  broad  transverse  plate,  rounded  at  its  lateral, 
and  concave  at  its  anterior  and  posterior  mar- 
gins. In  the  mole-cricket,  as  in  most  of  the 
beetles,  the  true  gula  is  well  developed  be- 
tween the  occipital  foramen  and  sub-men- 
tum,  and  in  that  insect  is  of  a  trian- 
gular shape,  with  its  apex  directed  backwards. 


Fig.  374. 


Under  surface  of  mouth  of  Btatta.    Figures  as 
before. 

But  in  the  Blattida  (fig.  374,  m ),  the  sub-men- 
tum  and  gula  appear  to  have  been  closely 
united,  without  trace  of  their  former  distinc- 
tion, and  the  men  turn  (I)  is  short,  transverse, 
and  articulated  with  the  palpiger  and  ligula 
(i).  From  the  complexity  of  parts  into 
which  the  ligula  is  divided,  we  consider  it 
better,  as  before  remarked,  to  omit  any  parti- 
cular description  of  the  palpiger,  which,  Mr. 
Newman  states,  is  situated  between  the  proper 
ligula  and  men  turn.  In  Blatta  the  ligula  is 
divided  into  six  distinct  parts.  To  two  of  these 
(i)  are  attached  the  labial  palpi,  and  they  ap- 
pear to  be  the  palpiger  as  described  by  New- 
man. From  the  upper  anterior  margin  of 
these,  nearest  the  median  line,  arise  two  short 
lobes,  covered  partly  on  their  exterior  margins 
by  two  larger  ones,  the  paraglossaz  (*  *), 
which  become  of  much  importance  in  the 
mouth  of  Hymenoptera.  In  the  mole-cricket 
the  ligula  is  divided  only  into  four  lobes,  all  of 
which  are  exceedingly  narrow,  and  very  much 
resemble  palpi.  In  some  of  the  Locustida, 
the  labium  is  simply  divided  in  the  median 
line  a.s  in  Hydrous.  The  true  ligula  or  tongue 
(Jig.  374*)  in  most  of  the  Orthoptera  is  a 
soft  projecting  fleshy  body,  like  the  tongue  of 


other  animals,  and  is  situated  above  the  men- 
turn  and  sub-mentum,  within  the  mouth  of 
which  it  forms  the  floor  and  passage  to  the 
pharynx.    In  Blatta  it  is  narrow  and  elon- 
gated, and  projects  as  far  as  the  middle  of  the 
ligula,  and  it  is  even  more  largely  developed  in 
the  Locustida  and  Achetida.    In  the  maxilla 
we  recognise  the  same  parts  as  in  Coleoptera, 
with  but  little  variation  of  form  except  in  the 
galea  and  lacinia.    The  lacinia  (5)  is  usually 
elongated,  and  furnished  with  a  sharp  hook 
bipid  at  its  apex.    In  Achetidaz  and  most  of 
the  vegetable  feeders  it  is  strong  and  much 
bent  at  its  extremity,  but  in  the  omnivorous 
Bluttidte  it  is  also  sharpened  to  a  cutting  edge 
along  its  inner  margin.    It  is  in  this  order  of 
insects  that  the  secondary  appendage  of  the 
maxilla,  the  galea  (6),  is  most  fully  developed, 
and  covers  the  lacinia  so  completely  as  to  serve 
the  office  of  a  shield  or  helmet.    In  the  vege- 
table-feeding Locustida,  this  part  is  sometimes 
three-jointed,  as  observed  by   Newman*  in 
Acri/dium,  but  usually  it  is  simply  an  obtuse 
double-jointed  organ,  hollowed  on  its  inner 
side;  but  in  the  Blattida  it  is  expanded  at  its 
extremity   into   a  thick   oval  bulb,  or  soft 
cushion,  encircled  with  fine  hairs,  evidently 
well  adapted  for  touching  or  feeling.    In  all 
the  Orthoptera,  but  more  particularly  in  the 
Blattida,  the  articulation  of  the  maxilla  with 
the  sub-mentum  is  less  compact  than  in  the 
Coleoptera  ;  and  this  appears  to  be  referable  to 
the  same  circumstance  as  before  noticed  with 
regard  to  the  mobility  of  the  anterior  clypeus, 
the  voracious  habits  of  the  insect.    Thus,  to 
allow  of  very  extensive  motion  to  the  parts,  the 
stipes  (2)  is  articulated  at  an  angle  with  the 
cardo  (1),  and  a  broad  muscular  structure,  at- 
tached along  the  inner  border  of  the  lacinia,  as 
far  as  the  base  of  its  sharp  articulated  apex, 
upon  which  it  acts,  is  interposed  between  the 
maxilla  and  sub-mentum,  and  forms  part  of  the 
inferior  boundary  of  the  mouth.    The  mandibles 
in  this  order  of  insects,  as  remarked  by  Marcel 
de  Serres,-)-  are  more  perfectly  constructed  than 
in  any  other.    In  those  which  masticate  their 
food,  and  devour  large  quantities  of  vegetable 
matter,  as  the  Locustida,  the  mandibles  are 
furnished  both  with  cutting  and  grinding  sur- 
faces.   The  anterior  or  apical  margin  is  deve- 
loped into  acute  cutting  teeth,  somewhat  like 
the  canine  teeth  of  vertebrata,  while  the  inner 
and  posterior  part  of  the  mandible  is  broad, 
flattened,  and  covered  with  elevated  irregular 
ridges,  like  the  teeth  of  some  Herbivora,  and  is 
admirably  adapted  for  grinding  or  chewing. 
This  complicated  structure  does  not  exist  in 
the  more  carnivorous  species,  the  Blattida,  in 
which  the  mandibles  are  arched,  and  indented 
with  sharp  triangular  teeth  (fig.  3TS,f),  very 
closely  resembling  the  cutting  teeth  of  Carni- 
vore, and  are  articulated  by  strong  condyles  at 
the  side  of  the  head,  on  a  line  with  the  articula- 
tion of  the  clypeus  anterior,  and  not  so  far  back 
as  that  of  the  maxilla.    The  eyes  in  Orthoptera 
are  usually  exceedingly  prominent  and  round, 
but  not  large,  except  in  Blatta,  in  which  they 
*  P.  32. 

t  Annales  des  Museums,  No.  xvi.  p.  56. 


INSECTA. 


897 


are  kidney-shaped,  and  are  spread  over  a  great 
part  of  the  sides  of  the  head.  The  ocelli, 
which  are  found  in  most  of  this  order,  do  not 
exist  in  Blatta.  They  are  very  distinct  in  the 
Gryllida  and  Locustida,  and  also  in  the  mole- 
cricket  ;  but  it  is  remarkable,  as  Mr.  Kirby  for- 
merly observed,  that  they  are  not  met  with  in 
the  pupa  or  larva  state  of  these  insects.  In  the 
pupa  of  the  mole-cricket  there  are  simply  two 
slightly  elevated  tubercles,  in  the  situation  in 
which  the  ocelli  are  afterwards  developed. 
They  thus  appear  to  have  reference  to  some 
particular  condition  of  the  perfect  insect,  al- 
though the  habits  of  the  three  states  appear  to 
be  similar.  The  antenna  are  organs  of  much 
importance,  and  are  usually  of  considerable 
length,  except  in  the  carnivorous  Mantida,  or 
praying  insects,  in  which  they  are  very  short. 
These  insects,  which  take  their  living  food  by 
sight  alone,  have  the  shortness  of  their  an- 
tenna?, the  supposed  organs  of  hearing,  com- 
pensated for  by  the  immense  size  of  their  large 
globular  cornea?,  situated  at  the  superior  angles 
of  the  head,  so  as  to  enable  the  insect  to  see  in 
every  direction.  But  in  those  which  reside  in 
the  dark,  or  which  seek  their  food  by  the  aid  of 
other  senses,  the  antenna?  are  exceedingly  long, 
and  formed  of  an  immense  number  of  joints, 
especially  in  the  Gryllida,  Achetida,  and 
Blattida,  which  are  noted  for  acuteness  of 
hearing.  In  the  interior  of  the  head  the  laminae 
squamosa  are  thick  and  strong,  and  are  articu- 
lated, as  in  Hydrous,  with  the  angles  of  the  epi- 
cranial suture  superiorly,  and  inferiorly  with  the 
lamina:  posterior es,  and  the  tentorium  forms  a 
distinct  ring,  as  in  Lucanus. 

In  the  Neuroptera  we  recognise  the  same 
elementary  parts  in  the  head  and  mouth  as  in 
the  preceding  Orders,  but  in  this  they  are  de- 
veloped into  new  forms.  The  epicranium,  so 
conspicuous  in  the  former,  is  reduced  to  its 
minimum  in  this  Order,  owing  to  the  immense 
development  of  the  organs  of  vision,  which, 
attaining  their  greatest  extent  in  (Es/nia  gran- 
dis,  are  expanded  over  the  whole  of  the  upper 
and  lateral  surfaces  of  the  head,  and  are  ap- 
proximated together  in  the  median  line,  leaving 
only  the  epicranial  suture  between  them.  A 
small  portion  only  of  the  epicranium  exists 
anterior  to  these  great  cornea?,  but  in  that  por- 
tion, as  usual,  are  situated  the  ocelli;  while 
the  minute  antennse,  reduced  also  to  their  mi- 
nimum of  size  in  these  Libellulida,  the  most 
rapacious  and  insatiable  of  all  insects,  are  still 
situated,  as  in  Coleoptera,  at  the  external  angles 
of  the  suture.  In  the  dilated  anterior  portion 
of  the  head  we  distinctly  recognize  the  clypeus 
posterior  and  anterior,  and  below  these  the 
transverse  cordiform  lubrum,  separated  by  su- 
tures, but  freely  articulated  together  as  in  Or- 
thoptera.  At  the  lower  concave  margin  of  the 
clypeus  anterior  in  CEs/ina  grandis  is  a  short 
triangular  plate  intervening  between  the  clypeus 
and  labrum,  and  articulating  with  both  like  a 
distinct  segment;  it  is  probably  only  part  of 
the  labrum.  On  the  under  surface  of  the  head 
the  gula  and  sub-mentum  are  indistinct,  and 
merged  as  it  were  in  the  construction  of  three 

VOL.  II. 


immensely  dilated,  doubly  articulated  plates, 
which  cover  the  whole  lateral  and  under  sur- 
face of  the  mouth.  The  anterior  portion  of 
the  middle  plate,  which  in  (Eshna  is  rounded 
at  its  anterior  margin,  is  the  true  ligula,  while 
the  articulation  behind  it,  from  which  arise  the 
lateral  plates,  is  the  analogue  of  the  mentum. 
The  two  lateral  plates,  composed  each  of  two 
articulations,  and  in  some  species  also  of  a 
third  very  minute  one  in  the  form  of  a  short 
spine  at  the  apex,  we  regard,  with  Brulle,*  as 
the  proper  labial  palpi  immensely  dilated.  The 
mandibles  concealed  within  the  mouth  are 
short,  strong,  and,  in  Libellula  quadrimaculnta, 
arched.  At  the  apex  they  are  bifid,  and  armed 
with  two  sharp  triangular  teeth,  and  at  their 
base  with  four  sharp-pointed  ones,  excavated, 
and  placed  in  different  directions,  adapted  for 
crushing  and  cutting  rather  than  for  mastica- 
ting the  food.  Within  the  head  they  are  arti- 
culated with  portions  of  the  epicranial  and  ba- 
silar regions,  as  in  Coleoptera.  The  maxilla  are 
long  and  prehensile.  The  true  palpi  are  en- 
tirely absent,  but  the  galea  exists  as  an  oblong 
articulated  lobe,  and  the  lucinia,  which  is  arti- 
culated at  its  base  and  sharpened  along  its 
inner  margin,  as  in  the  Blattida,  is  armed  at 
its  apex  with  four  crooked  sharp-pointed  teeth, 
while  the  cardo  is  long,  and  articulated  with 
the  base  of  the  maxilla  at  an  angle,  to  allow  of 
extensive  motion,  as  in  the  maxilla  of  Orthop- 
tera.  In  other  families  of  the  Neuroptera,  as 
in  the  Panorpida,  the  organs  of  manducation 
are  small,  but  the  anterior  part  of  the  head  is 
elongated  into  a  rostrum,  occasioned  by  the 
narrowing  and  extension  of  the  clypei,  as  we 
have  before  noticed  in  the  Curculionida,  while 
in  the  Phryganida,  which  take  no  food  in  their 
perfect  state,  the  parts  of  the  mouth  are  almost 
atrophied. 

In  Hymenoptera  the  mouth  assumes  an  en- 
tirely new  form,  but  the  changes  in  it  are  con- 
fined to  the  maxilla?  and  labrum,  which  are 
soon  to  become  its  chief  organs.  The  head, 
placed  vertically  on  the  thorax,  is  still  well  de- 
veloped. The  epicranial  region  is  large,  and 
extends  very  nearly  to  the  insertion  of  the 
antenna?  on  the  front.  In  most  species  it  is 
densely  covered  with  hairs,  and  the  ocelli  (fig. 
375,  b,)  which  are  constant  in  this  class,  are 
usually  arranged  in  a  triangle  on  its  most  ver- 
tical part.  The  cornea  (c)  are  large  and  kid- 
ney-shaped, and  cover  part  of  the  lateral  sur- 
face of  the  head,  leaving  between  them  a  broad 
front,  occupied  by  the  clypei  (d)  and  part  of 
the  epicranium.  But  in  the  males  of  the  luve- 
bee,  which  come  abroad  only  in  the  brightest 
sun-light  in  quest  of  the  female,  this  space  is 
diminished,  and  the  cornea?  are  expanded  over 
part  of  the  front,  and  the  whole  of  the  epicra- 
nial region,  as  in  the  Libellula;  the  most  ex- 
tensive vision  being  required  by  these  insects, 
to  enable  them  to  discover  the  object  of  their 
solicitude,  as  by  the  other  in  the  pursuit  of  its 
prey.    In  some  of  the  pollenivorous  and  pre- 

*  Annal.  Soc.  Enlom.  de  France,  torn.  ii.  p. 
343. 

3  N 


898 


INSECTA. 


Fig.  375. 


Anterior  and  inferior  views  of  the  mouth  and  head  of 
Antliophora  return. 
A,  antenna  ;  b,  epicranium  and  ocelli ;  c,  cor- 
nea •,  d,  clypeus  anterior  ;  e,  labrum  ;  f,  mandi- 
ble ;  g,  the  maxilla;  h,  its  palpus;  i,  feeler- 
bearer  or  part  of  the  ligula ;  It,  labial  palpus  ;  /, 
mentum;  m,  sub-mentum;  1,  cardo  of  the  maxilla  ; 
2,  stipes  ;  5,  the  lacinia  or  blade  ;  *,  ligula;  **,pa- 
raglosscB,  its  lateral  lobes. 

daceous  genera,  the  Tenthredinida  and  Ves- 
pida,  the  clypeus  posterior  seems  to  have  be- 
come entirely  obliterated,  unless  we  regard  the 
broad  clypeus  in  these  insects,  as  in  the  Hornet, 
the  posterior  one,  and  the  plate  concealed  be- 
neath it,  within  the  mouth,  to  which  the 
labrum  is  attached,  as  the  anterior.  But  we 
are  not  inclined  to  do  this,  because  in  some  of 
the  Ichneumonida  and  Sphecida  a  trace  of  the 
clypeus  posterior  remains  a  little  anterior  to  the 
antennae.  In  Ichneumon  Atropos  the  clypeus 
is  narrowed  and  depressed  in  its  middle,  as  if 
originally  formed  of  two  parts,  while  in  Ammo- 
phila  vulgaris  the  clypeus  posterior  is  clearly 
indicated  as  a  minute  triangular  plate  situated 
in  the  middle  line,  immediately  beneath  the 
insertion  of  the  antennae,  and  it  exists  in  a 
similar  form  in  some  of  the  Apidct,  as  in  the 
large  female  Bombus  lapidarius,  and  in  some 
specimens  of  Anthophora,  the  clypeus  posterior 
being  in  all  instances  bounded  by  a  trace  of  the 
triangular  suture.  The  labrum  (c)  is  always 
distinct,  but  variously  formed.  In  Vespida  it 
is  narrow,  acute,  and  hidden  beneath  the  ante- 
rior clypeus;  in  the  leaf-cutting  bees,  Mega- 
chile,  it  is  narrow  and  quadrate;  but  in  the 
hive  and  humble-bees  it  is  large,  and  rounded 
at  its  anterior  margin.  The  mandibles  are  sub- 
ject to  considerable  variation  of  form.*  In 

*  See  Essay  on  Fossorial  Hymenoptera,  by  W.  E. 
Shuckard,  p.  12,  et  seq. 


some,  as  in  Ammophila,  which  burrows  in  the 
sand,  they  are  long,  hooked,  and  furnished 
with  but  a  single  tooth  at  the  apex,  without 
cutting  edges ;  and  they  are  of  somewhat  the 
same  form  in  Anthophora  (fig.  375,/),  whose 
habits  of  life  in  this  respect  are  similar.  In  the 
Vespidie,  which  gather  the  materials  for  their 
nests  by  rasping  off  little  packets  of  fibres  from 
decaying  wood,  they  are  broad,  triangular,  and 
armed  along  their  edges  with  strong  teeth ;  and 
such  is  also  their  structure  in  Anthidium  mani- 
catum,  which  scrapes  off  the  down  from  the 
woolly  stems  and  leaves  of  plants  for  the  same 
purpose;  while,  in  the  hive-bee,  which  em- 
ploys them  in  moulding  the  soft  wax  in  the 
construction  of  the  combs,  they  are  shaped  at 
the  apex  like  a  spoon,  without  indentations ; 
their  form  in  each  instance  being  thus  dis- 
tinctly referable  to  the  habits  of  the  insects. 
In  the  gregarious  species  there  is  also  a  dif- 
ference in  their  form  in  the  two  sexes,  those  of 
the  males  being  often  smaller  and  less  curved 
than  of  the  females,  or  workers,  and  they  are 
always,  particularly  in  the  Bombi,  more  densely 
covered  with  hairs. 

In  the  whole  of  the  Terebrantia,  Pupophaga, 
and  some  of  the  Aculeata  the  mandibles  are 
still  the  chief  cibarian  organs ;  the  Athalia  em- 
ploys them  in  masticating  the  pollen  of  flowers, 
and  the  maxillae  and  labium  in  sipping  the 
honey;  while  the  omnivorous  Formicidce  and 
Vespidte  employ  them  in  tearing  and  masti- 
cating their  food,  whether  it  be  the  pulpy  sub- 
stance of  fruits,  or  the  muscles  and  hard  cover- 
ings of  other  insects.  In  the  Apidce.  the  chief 
use  of  the  mandibles  is  in  constructing  the 
nest,  while  the  maxillae  and  labium  are  the 
only  organs  employed  in  taking  food.  In  the 
strictly  carnivorous  families  the  maxilla  are  not 
longer  than  in  the  preceding  Orders.  In  most 
of  these,  as  well  also  as  in  the  Terebrantia  and 
Chri/sidida,  the  extremity  of  each  maxilla  is 
obtuse,  and  divided  into  a  distinct  lacinia  and 
galea,  and  the  palpi  are  long  and  six-jointed. 
In  the  Formicidce  and  Vespidce,  which  subsist 
upon  fluid  as  well  as  solid  aliment,  their  length 
is  increased ;  but  in  the  true  Apidce,  which 
subsist  entirely  upon  honey,  they  are  drawn 
out  to  a  great  length,  and,  with  the  labium  be- 
neath, form  a  tube  through  which  the  aliment 
is  conveyed  to  the  mouth,  as  in  the  hive  and 
humble-bees.  In  these  species  the  cardo  (1) 
is  long,  slender,  and  formed  of  two  parls,  which 
conjointly  articulate  with  the  stipes  (2).  The 
longest  of  these,  the  basilar  portion,  has  two 
apophyses  at  its  extremity,  and  is  articulated 
with  the  anterior  part  of  the  base  of  the  cra- 
nium, at  the  inner  side  of  the  articulation  for 
the  mandibles,  exactly  as  in  Coleoptera;  and 
its  muscles  in  like  manner  are  attached  to  the 
lateral  and  inferior  parts  of  the  head  and  orbital 
plates.  It  is  the  lora,  or  lever  of  Kirby,  which 
enables  the  insect,  by  the  additional  articula- 
tion of  its  second  part  with  the  sub-mentum,  to 
thrust  out  the  maxillae  and  labrum  together  to  a 
great  distance.  The  part  that  articulates  with 
the  sub-mentum,  the  proper  cardo  of  Kirby,  is 
very  short  in  Bombus  lapidarius,  but  of  consi- 


INSECTA. 


899 


Fig.  376. 


Lateral  view  of  the  mouth  of  Anthophora.  Letters 
and  figures  as  before.    12,  the  lingua,  or  tongue. 

derable  length  in  Anthophora.  In  each  in- 
stance it  is  broadest  at  its  articulation  with 
the  stipes,  and,  passing  backwards  diagonally, 
unites  at  its  extremity  with  a  corresponding 
part  of  the  opposite  side,  and  the  two  thus 
joined  articulate  with  the  narrow  sub-mentum, 
the  fulcrum  of  Kirby.  The  stipes  forms  the 
lateral  basilar  part  of  the  maxilla,  and  is  shorter 
in  Anthophora  than  in  Bombus,  in  which  it  is 
about  one-third  of  the  length  of  the  maxilla. 
The  palpifer  is  also  distinct  (3).  The  lacinia  (5) 
is  of  great  length,  and  gradually  tapers  to  its 
extremity.  Internally  it  is  slightly  concave, 
and  externally  is  covered  with  a  few  scattered 
hairs.  It  is  articulated  freely  with  the  stipes 
and  palpifer,  upon  which  it  is  inflected  in  a 
state  of  rest  to  form  a  sheath  for  the  labium, 
when  the  parts  of  the  mouth  are  folded.  When 
the  maxillae  are  extended  to  form  the  sucking 
tube  with  the  labium,  they  are  a  little  separated 
at  their  base,  and  inclose  between  them  the 
cavity  of  the  mouth,  within  which  is  a  soft 
fleshy  body,  the  lingua  (12)  or  true  tongue, 
situated  anterior  to  and  serving  as  a  valve  to  the 
pharynx.  The  sub-mentum  (m)  is  articulated 
by  a  single  joint  with  the  united  extremities  of 
the  two  cardines  (13).  It  is  long  and  narrow 
in  Anthophora,  but  short  and  triangular  in 
Bombus.  It  is  attached  at  its  sides  by  a  fine 
membrane  to  the  under  surface  of  the  head  and 
throat.  The  mentum  (I)  articulates  with  the 
sub-mentum,  and  is  an  elongated  rounded  plate, 
which  forms  internally  a  channelled  passage 
to  the  pharynx.  Within  it  are  inserted  the 
muscles  of  the  labial  palpi  (/c).  These  organs 
are  long  and  styliform,  and  arise  from  a  space 
at  the  base  of  the  ligula,  the  part  described  as 
the  palpiger  by  Newman.  Their  great  length 
is  occasioned  by  an  excessive  elongation  of  the 
second  basial  joint,  which  is  sometimes  as  long 
as  the  whole  maxilla  itself,  and  is  furnished  at 
its  distal  extremity  with  a  minute  brush  of 
hairs,  and  also  articulates  with  the  remaining 


short  joint  of  the  organ.  The  remaining  por- 
tion of  the  labium  is  divided  into  three  parts* 
The  two  lateral  ones  are  short  styliform  pro- 
cesses, the  paraglossa  (**),  and  the  central  one, 
commonly  called  the  tongue  of  the  bee,  is  the 
part  employed  by  the  insect  in  gathering  honey. 
In  Apis,  Bombus,  and  Anthophora  it  is  a  long 
tapering  muscular  organ,  formed  of  an  immense 
number  of  short  annular  divisions,  and  densely 
covered  throughout  its  whole  length  with  long 
erectile  hairs.  It  is  not  tubular  but  solid,  and 
when  actively  employed  is  extended  to  a  great 
distance  beyond  the  other  parts  of  the  mouth, 
but  when  at  rest  is  closely  packed  up  and  con- 
cealed between  the  maxillae.  The  manner  in 
which  the  honey  is  obtained  when  the  organ  is 
plunged  into  it  at  the  bottom  of  a  flower,  is  by 
lapping,  or  a  constant  succession  of  short  and 
quick  extensions  and  contractions  of  the  organ, 
which  occasion  the  fluid  to  be  accumulated 
upon  it,  and  ascend  along  its  upper  surface, 
until  it  reaches  the  orifice  of  the  tube  formed 
by  the  approximation  of  the  maxilla  above, 
and  the  labial  palpi  and  this  part  of  the  ligula 
below.  At  each  contraction  a  part  of  the  ex- 
tended ligula  is  drawn  within  the  orifice  of  the 
tube,  and  the  honey  with  which  it  is  covered 
ascends  into  the  cavity  of  the  mouth,  assisted 
in  its  removal  from  the  surface  of  the  ligula  by 
the  little  brush  of  hairs  with  which  the  elon- 
gated second  joint  of  each  labial  palpus  is  fur- 
nished. From  the  mouth  the  honey  is  passed 
on  through  the  pharynx  into  the  oesophagus  by 
the  simple  act  of  deglutition,  as  in  other  ani- 
mals. In  Anthidium  the  ligula  is  not  longer 
than  the  labial  palpi;  while  in  the  Andrenida: 
all  the  parts  of  the  mouth  are  much  shortened, 
and  resemble  similar  parts  in  the  Vespidce  in 
being  divided  into  four  lobes*  In  the  latter 
insects  the  ligula  is  quadrifid,  and  is  dilated 
at  its  apex,  and  each  lobe  is  terminated  by  a 
minute  gland.f  The  two  lateral  lobes,  para- 
glossaz,  are  shorter  than  the  middle  ones.  In 
Tenthredinida  the  ligula  is  also  short,  but  is 
divided  only  into  three  lobes. 

We  have  thus  seen  that  the  head  and  its  ap- 
pendages are  most  perfectly  developed  as  a 
whole  in  the  Coleoptera,  and  that  in  passing 
through  the  succeeding  Orders  of  Mandibulata 
certain  parts  are  more  or  less  developed  in  each 
Order,  in  accordance  with  the  general  habits 
and  mode  of  life  of  the  insects ;  that  in  the 
carnivorous  and  omnivorous  families,  and  in 
those  whose  habits  of  life  require  a  great 
amount  of  strength,  either  in  procuring  their 
food  or  in  the  construction  of  their  nests,  the 
mandibles  are  the  most  important  of  the  oral 
organs,  and  are  most  largely  developed.  But 
as  we  pass  from  insects  with  these  habits  to  the 
Haustellata,  whose  food  and  modes  of  life  are 
of  an  entirely  different  description,  the  man- 
dibles lose  their  importance,  and  become  atro- 
phied, and  their  office,  now  altered  in  its  cha- 
racter, is  performed  by  the  maxillae  and  labium, 


22. 


Newman.    Paper  on  the  Head  of  Insects,  p. 


t  Curtis.  Westwood. 


3  N  2 


900 


INSECTA. 


the  development  of  which,  in  the  higher  forms 
of  insects,  is  only  of  secondary  importance,  com- 
pared with  that  of  the  mandibles,  but  is  now 
carried  to  so  great  an  extent  that  these  organs 
become  almost  or  entirely  the  sole  means  of 
taking  food.  Not  only  do  these  changes  take 
place  in  the  parts  of  the  mouth,  but  the  whole 
head  undergoes  a  similar  alteration  in  the  rela- 
tive form  and  size  of  its  parts,  occasioned  by 
the  excessive  development  of  the  organs  of  vi- 
sion.   Thus  in  the  Lepidoptera,  (Jig.  377,)  the 


Fig.  377. 


The  head,  and  parts  of  the  mouth  of  Sphinx  Ugustri. 
A ,  antenna  ;  b,  epicranium  ,  c,  cornea ;  d,  cly- 
peus  posterior;  e,  labrum;  f,  mandible;  g,  max- 
illa or  proboscis  ;  h,  maxillary  palpus;  B,  base  of 
the  maxilla  with  the  mandibles  and  labrum;  C, 
lateral  view  of  the  same. 

lateral  and  a  large  portion  of  the  inferior  surface 
of  the  head  is  entirely  occupied  by  the  cornea? 
(r),  which  are  also  extended  far  forwards  upon 
the  anterior.  The  occipital  region  is  confined 
to  the  flat  surface  that  is  approximated  to  the 
prothorax.  The  epicranium  (6)  is  distinct,  and, 
as  in  the  preceding  Orders,  extends  as  far  an- 
teriorly on  each  side  as  the  base  of  the  antennae 
between  the  corneas,  but  the  suture  that  sepa- 
rates it  from  the  clypeus  posterior  (d)  is  almost 
transverse.  The  clypeus  posterior  is  very  large, 
and  occupies  the  whole  of  the  space  between  the 
corneas,  on  the  front  of  the  head.  It  is  convex 
as  in  Neuroptera,  and  is  narrowest  at  its  inferior 
part.  The  clypeus  anterior  appears  to  exist  in 
the  form  of  a  minute  transverse  plate,  a  little 
elongated  in  its  middle  on  the  hinder  part,  and 
separated  by  a  transverse  groove  on  its  anterior 
from  a  much  smaller  plate,  the  labrum  (e),  with 
which  it  is  consolidated.  This  part,  which  was 
first  detected  in  Lepidoptera  by  the  accurate 
Savigny,*  is  also  a  small  convex  transverse 
plate  with  a  little  triangular  scale  at  its  anterior 
margin,  fitted  closely  to  the  front  of  the  max- 
illa?. In  Sphinx  Ugustri,  ( fig.  377,)  the  separa- 

•  Memoires  sur  les  Animaux  sans  Verttibres. 


tion  of  the  labrum  by  suture  from  the  part  which 
we  regard  as  the  clypeus  anterior,  is  distinct, 
but  it  appears  to  have  been  overlooked  by  Sa- 
vigny and  others.    On  each  side  of  the  labrum 
are  the  rudiments  of  the  mandibles  (  /").  They 
are  two  minute,  triangular  plates,  attached  in 
part  to  the  labrum  and  margin  of  the  clypeus, 
to  which,   as  Savigny  has   remarked,  they 
appear  to  be  soldered.    They  are  applied  to 
the  base  of  the  maxillae,  and  in  Sphinx  appear 
each  to  be  formed  of  two  parts,  and  are  co- 
vered along  their  inner  margin  with  stiff  hairs. 
They  are  the  remains  of  the  large  corneous 
mandibles  of  the  larva.    We  are  indebted  for 
their  discovery  to  the  indefatigable  researches 
of  Savigny,  who  first  traced  their  identity.  The 
labium,  which  forms  so  conspicuous  a  part  of 
the  mouth  in  the  preceding  Orders,  like  the 
mandibles,  is  reduced  to  insignificance  in  this. 
It  is  a  small  triangular  plate,  closely  attached 
to  the  under  surface  of  the  head,  at  the  base  of 
the  maxillae,  and  its  division  into  parts,  so  dis- 
tinct in  other  insects,  is  now  scarcely  perceptible. 
The  labial  palpi  (k)  arise  one  on  each  side  of 
the  labium.    They  are  usually  long,  hairy,  and 
three-jointed,  and  are  reflected  on  the  front  of 
the  head.  Next  to  the  maxillae  they  are  the  most 
conspicuous  parts  of  the  mouth,  particularly 
in  Fyralidte  and  Tortricida,  in  which  they  are 
long  and  pointed.    The  lingua  has  been  sup- 
posed to  be  entirely  absent  in  Lepidoptera.  It 
was  not  detected  by  Savigny.    Latreille  be- 
lieved it  to  exist  in  the  suture  at  the  floor  of 
the  mouth,  but  Mr.  Newman  has  observed  a 
small  mammiform  protuberance  in  Sphinx  li- 
gustri  which  he  regards  as  the  analogue  of  the 
tongue  in  this  Order.    The  labrum,  mandibles, 
and  labium  are  entirely  concealed  by  the  re- 
flected labial  palpi  and  a  dense  clothing  of 
scales,  and  are  only  observed  when  the  anterior 
part  of  the  head  is  completely  denuded  of 
these  coverings.     Their  atrophied  condition 
affords  a  beautiful  illustration  of  the  law  that 
in  proportion  as  the  functions  of  an  organ  be- 
come suspended,  or  are  rendered  unnecessary 
by  the  employment  of  other  parts,  the  organ 
itself  becomes  wasted  and  utterly  useless,  and 
perhaps  entirely  disappears.    Thus  in  those 
Lepidoptera  whose  food  is  liquid  honey  pro- 
duced in  the  deep  chalices  of  flowers,  the 
short  mandibles  of  the  voracious  herbivorous 
larva  would  be  entirely  useless  to  the  perfect 
insect,  and  its   food  would  be  inaccessible 
to  it.    Accordingly  we  find  that  the  man- 
dibles  are   now   unimportant   organs,  and 
the  office  of  conveying  food  to  the  mouth  is 
performed  solely  by  the  maxillae  (</),  which 
are  extended  in  the  shape  of  a  long  sucking 
tube.    Each  maxilla  is  composed  of  an  im- 
mense number  of  short,  transverse,  muscular 
rings.    It  is  convex  on  its  outer  surface,  but 
concave  on  its  inner,  and  the  tube  is  formed  by 
the  approximation  of  the  two  organs.  When 
at  rest  they  are  rolled  up  like  a  watch-spring, 
between  the  large  labial  palpi,  but  are  capable 
of  being  darted  forth  in  an  instant.    They  are 
the  so-called  tongue,  or  proboscis  of  the  but- 
terfly and  moth.    Each  maxilla  has  usually 


INSECTA. 


901 


been  described  as  being  hollow  in  its  interior, 
or  forming  "  in  itself  a  tube,"*  which  appears 
to  have  arisen  from  the  circumstance  of  there 
existing  in  each,  one  or  more  large  tracheal 
vessels,  (Jig.  378,  6,  e,)  connected  with  the 
tracheae  of  the  head,  and  which  are  divided,  as 
they  approach  the  extremity  of  the  organ,  into  a 
great  number  of  minute  ramifications,  but  which 
have  no  communication  with  the  external  sur- 
face, their  distribution  being  precisely  similar  to 
that  of  the  trachea;  in  other  parts  of  the  body. 
The  maxilla  is  composed  of  elementary  parts, 
as  in  the  preceding  Orders,  but  they  are  not 
easily  distinguished.  The  long  extensile  por- 
tion is  the  proper  lacinia,  which  is  constricted 
at  its  base,  immediately  beyond  which  is  situ- 
ated, in  Sphinx  ligustri,  a  minute  three-jointed 
hairy  palpus  (h).  Mr.  Newman  could  not  de- 
tect this  maxillary  palpus  in  Sphinx,f  and  hence 
concluded  that  it  was  obsolete  in  this  family. 
It  is  indeed  exceedingly  minute  and  easily 
overlooked,  but  is  distinctly  three-jointed,  and 
densely  covered  with  long  hairs.  The  structure 
of  the  maxillae  in  different  genera  and  species 
is  particularly  interesting,  and  their  length  is 
exceedingly  various.  Thus  in  the  Sphingida, 
in  Smerinthus  ocellutus,  which  takes  no  food, 
they  scarcely  exceed  one-eighth  of  an  inch, 
while  in  Sphinx  ligustri,  which  continues  ho- 
vering on  the  wing  while  extracting  the  sweets 
from  a  flower,  they  are  nearly  two  inches  in 
length,  and  this  is  also  the  case  in  the  hum- 
ming-bird moth,  Macroglossa  stellatarum. 
In  the  butterflies,  and  in  many  of  the  Nuc- 
tuida,  they  are  often  about  equal  to  the  length 
of  the  body.  The  inner  or  concave  surface 
which  forms  the  tube  is  lined  with  a  very 
smooth  membrane,  and  extends  along  the  an- 
terior margin  throughout  the  whole  length  of 
the  organ,  as  in  the  transverse  section,  (fig. 
378,  6,  b.)  At  its  commencement  at  the  apex 
it  occupies  nearly  the  whole  breadth  of  the 
organ,  and  is  rather  smaller  than  at  its  termi- 
nation near  the  mouth,  where  the  concavity  or 
groove  does  not  occupy  more  than  about  one- 
third  of  the  breadth.  In  some  species  the  ex- 
tremity of  each  maxilla  is  furnished  along  its 
anterior  and  lateral  margin  with  a  great  number 
of  minute  papillae,  but  in  others  these  parts  are 
entirely  absent.  They  are  extensively  deve- 
loped in  some  of  the  butterflies,  as  in  Vanessa 
atalanta,  (Jig.  378,  1,  2,  c,)  in  which  they 
are  little  elongated  barrel-shaped  bodies,  (4,  c,) 
terminated  by  three  smaller  papillae,  arranged 
around  their  anterior  extremity,  with  a  fourth 
one  a  little  larger  than  the  others  placed  in 
their  centre.  These  papillae  are  arranged  in 
two  rows  along  the  lateral  and  anterior  surface 
of  each  maxilla,  near  its  extremity,  for  about 
one-sixth  part  of  its  whole  length,  as  at  1,  and 
5,  c,  d.  There  are  seventy-four  in  each  max- 
illa, or  half  of  the  proboscis.  To  judge  from 
their  structure,  and  from  the  circumstance  that 
they  are  always  plunged  deeply  into  any  fluid 
when  the  insect  is  taking  food,  they  may  pro- 

*  Newman  on  the  Head  of  Insects,  p.  28. 
t  Op.  cit.  p.  28. 


Fig.  378. 


Parts  of  the  maxilla:  or  proboscis  of  Vanessa  atalanta. 

1,  external  surface  of  the  apex  with  the  double 
row  of  papilla;  ;  2,  internal  or  concave  surface ;  a, 
transverse  muscles;  b,  tube;  c,  papillae;  d,  hooks 
which  join  the  maxillae;  3,  one  of  the  hooks;  4, 
one  of  the  papillae  ;  5,  section  of  the  tip  of  the 
maxillae,  showing  the  position  of  the  papillae  on  each 
side  of  the tube  ;  6,  section  of  maxillae  near  their 
base,  showing  the  position  of  the  tube,  b;  the  large 
trachea,  e,  and  the  smaller  one  and  nerve,  f. 

bably  be  regarded  as  organs  of  taste.  They  are 
largely  developed  in  this  genus  of  insects,  but 
in  Pontia,  the  common  white  butterflies,  and 
in  Sphinx  ligustri  they  are  scarcely  perceptible. 
There  are  also  some  curious  appendages  ar- 
ranged along  the  inner  anterior  margin  of  each 
maxilla,  in  the  shape  of  minute  hooks,  which, 
when  the  proboscis  is  extended,  serve  to  unite 
the  two  halves  together.  They  were  first  no- 
ticed by  Reaumur,*  and  subsequently  by  Mr. 
Kirby.f  In  many  insects,  as  in  Sphinx  and 
Pontia,  they  have  more  the  appearance  of 
cilia,  like  the  barbs  of  a  feather,  than  of  hooks, 
but  in  Vanessa  they  are  falcated,  and  furnished 
with  an  additional  tooth  (3,  d)  a  little  beyond  the 
apex.  They  are  so  exceedingly  minute,  and  ar- 
ranged so  closely  together,  that  their  true  form 
is  with  difficulty  distinguished.  They  lock 
across  each  other  like  the  teeth  in  the  jaws  of 
some  fishes,  and  we  are  inclined  to  believe  that 
the  points  of  the  hooks  in  one-half  of  the  pro- 
boscis are  inserted,  when  the  organ  is  extended, 
into  little  depressions  between  the  teeth  of  the 
opposite  side,  so  that  they  form  the  anterior 
surface  of  the  canal,  but  of  this  we  are  not  con- 

*  Memoires,  &c.  torn.  i.  p.  125. 
$  Introduction,  vol.  i.  p.  394. 


902 


INSECTA. 


fident.  That  they  really  form  the  anterior  sur- 
face of  the  canal  or  tube  seems  evident  from 
the  distinctness  with  which  coloured  substances 
are  observed  to  pass  along  the  tube  when  the 
insect  is  taking  food. 

There  are  various  opinions  with  regard  to  the 
manner  in  which  the  food  ascends  the  tube  to 
the  mouth.  Some  have  imagined  that  it  is 
simply  by  capillary  attraction,  and  others,  the 
chief  of  whom  was  Lamarck,  that  it  is  forced 
along  by  successive  undulations  and  contrac- 
tions of  the  sides  of  the  tube,  occasioned  by 
the  action  of  the  transverse  muscles.  Kirby 
and  Spence*  believe  that  these  undulatory 
motions,  which  certainly  do  exist  to  a  consider- 
able extent,  are  not  sufficiently  powerful  to 
carry  along  the  food  with  the  rapidity  with 
which  it  usually  ascends,  but  that  the  lateral 
canals,  which,  as  we  have  just  shewn,  are  the 
proper  tracheae  of  the  organs,  assist  in  pro- 
ducing the  phenomenon  by  occasioning  a 
vacuum  in  the  mouth  and  tube  which  faci- 
litates the  conveyance  of  the  food  more  rapidly 
along  it.  That  something  of  this  kind  does  in 
reality  occur  is  proved  by  the  following  ob- 
servation. We  gave  sugared  water,  coloured 
with  indigo,  to  two  specimens  of  Pontia  nupi, 
and  on  attentively  examining  the  front  of  the 
organ  with  a  microscope  while  the  insects  were 
busily  employed  in  partaking  of  the  fluid,  ob- 
served the  particles  of  indigo  disseminated  in 
it  ascend  along  the  tube,  not  in  a  gradual  and 
regular  succession,  as  must  have  been  the  case 
had  the  ascent  of  the  fluid  been  occasioned 
simply  by  capillary  attraction,  but  pumped  up, 
as  it  were,  sometimes  in  a  full  stream  in  quick 
succession  for  one  or  two  seconds,  as  if  the 
insect  was  then  sipping  a  full  draught,  while 
at  others  a  few  particles  only  ascended  quickly, 
followed  by  still  fewer  with  a  much  slower 
motion  ;  thus  indicating  distinct  intervals  be- 
tween each  draught  or  ascent  of  fluid.  From 
these  circumstances  we  are  led  to  offer  the 
following  explanation  of  the  manner  in  which 
the  food  ascends  the  tube  to  the  mouth.  The 
instant  an  insect  alights  upon  a  flower,  it  makes 
a  forcible  expiratory  effort,  by  which  the  air  is 
removed  both  from  the  tracheae  that  extend 
through  the  proboscis,  and  from  those  with 
which  they  are  connected  in  the  head  and 
body,  some  of  which  we  shall  hereafter  see 
are  distributed  over  the  oesophagus  and  ali- 
mentary canal,  and  at  the  moment  of  applying 
its  proboscis  to  the  food  makes  an  inspiratory 
effort,  by  which  the  tube  is  dilated,  and  the 
food  ascends  it  at  the  instant  to  supply  the 
vacuum  produced,  and  is  carried  onward  by 
the  same  act  to  the  mouth,  and  from  thence 
by  the  action  of  the  muscles  of  the  pharynx 
into  the  oesophagus  and  stomach,  without  any 
interruption  of  the  function  of  respiration,  the 
constant  ascent  of  the  fluid  into  the  mouth 
being  assisted  by  the  action  of  the  muscles  of 
the  proboscis,  which  continue  in  action  during 
the  whole  time  the  insect  is  feeding.  By  this 
combined  agency  of  the  acts  of  respiration  and 

*  Introduction,  vol.  iv.  p.  470. 


the  muscles  of  the  proboscis,  we  are  enabled  to 
understand  the  manner  in  which  the  humming- 
bird sphinx  extracts  in  an  instant  the  honey 
from  a  flower  while  hovering  over  it  without 
alighting,  and  which  it  certainly  would  be 
unable  to  do  so  rapidly  were  the  ascent  of  the 
fluid  dependent  only  upon  the  action  of  the 
muscles  of  the  organ. 

In  Diptera  there  is  the  same  irregularity  in 
the  development  of  certain  parts  of  the  head  as 
in  Neuroptera  and  Hymenoptera.  The  shape 
of  the  head  is  usually  that  of  a  flattened  hemi- 
sphere, with  its  base  or  occipital  region  con- 
cave, and  approximated  to  the  prothorax,  as  in 
the  common  house-flies,  Muscida,  the  blood- 
suckers, Tabanida,  and  the  gad-flies,  (Estrida. 
But  in  others,  as  in  the  gnats,  Culicida, 
the  long-legs,  Tipulida,  and  the  Asilida, 
( fig.  349,)  it  is  either  convex  at  its  occipital  sur- 
face or  extended  in  the  form  of  a  short  neck. 
In  the  latter  instances  the  occipital  and  epi- 
cranial regions  are  large  and  distinct,  and  the 
cornea:  are  protuberant,  and  situated  a  little 
anteriorly  at  the  sides  of  the  head,  but  do  not 
much  encroach  upon  the  epicranium.  This  is 
not  the  case  in  the  Tabanida;,  &c.  in  which  they 
occupy  nearly  the  whole  of  the  epicranial 
region.  But  in  most  of  the  genera  in  which  the 
eyes  are  thus  expanded,  there  is  usually,  as  in 
Neuroptera,  some  portion  of  the  epicranial  region 
still  existing  in  the  form  of  a  small  triangular 
space  anterior  to  the  inner  margin  of  the  corneae. 
On  this  space  the  longitudinal  portion  of  the 
triangular  suture  is  often  distinctly  marked,  and 
extends  backwards  between  the  corneae  to  the 
occiput,  as  is  well  seen  in  Tabanus  bovinus. 
Anteriorly  it  extends  as  far  as  the  middle  line 
behind  the  antennas,  where  it  terminates,  thus 
distinctly  indicating  the  proper  boundary  of  the 
clupeus  posterior  in  this  order.  The  whole 
front  of  the  head  or  face  is  formed  of  the  two 
clypei,  which  are  so  united  together  as  to  be 
scarcely  distinguished  as  originally  separate 
parts.  They  together  form  a  broad  and  some- 
what lozenge-shaped  plate,  at  the  upper 
portion  of  which  are  situated  the  antennae, 
and  at  the  lower  or  anterior,  which  is  notched, 
the  labrum,  freely  articulated  with  it,  and 
which  is  usually  concealed  beneath  it.  In 
some  genera,  as  in  the  Tabanida,  the  an- 
tennae are  inserted  on  each  side  of  the  middle 
line,  into  little  fossae  close  to  the  triangular 
suture;  while  in  others, as  in  Ckrysotoxum  and 
Conops,  the  place  of  these  fossae  is  occupied  by 
little  elevations,  upon  which  those  organs  are 
seated,  sometimes  nearly  close  together,  as  in 
Hargus.  The  face  thus  formed  of  the  two 
clypei  is  developed  laterally  on  each  side  of 
the  corneae,  and  is  gradually  narrowed  from 
its  upper  part  to  its  lower,  where  it  is  articulated 
with  the  labrum.  In  Rhingia  rostrata  the 
posterior  clypeus  is  elongated,  and  forms  the 
long  projecting  front:  it  is  deeply  notched  at 
its  interior  margin,  where,  as  also  in  Volucella, 
is  a  very  minute  plate,  apparently  the  ana- 
logue of  the  clypeus  anterior.  The  cornea:, 
as  above  stated,  are  usually  the  most  conspi- 
cuous parts  of  the  head  in  Diptera,  and  form 


INSECTA. 


903 


its  lateral  regions.  They  are  always  largest,  as 
in  Neuroptera,  in  those  species  which  are  most 
constantly  abroad  in  the  brightest  light,  and 
are  expanded  over  nearly  the  whole  of  the 
epicranial  region,  as  in  Tubanus,  Chrysotoxum, 
and  Doros.  But  although  the  corneae  of  the 
compound  eyes  are  so  largely  developed,  the 
ocelli  also  are  almost  invariably  present  in  this 
order.  They  are  generally  three  in  number, 
placed  on  the  most  vertical  part  of  the  epi- 
cranium,  immediately  behind  the  proper  cornea. 
This  is  their  situation  in  Musca,  Helophilus,  and 
Straliomys,a.nd  also  in  the  gnat,  Culex  annulcttus, 
but  we  have  not  observed  them  in  a  neigh- 
bouring genus,  Pedicia.  Professor  Muller* 
believes  that  the  ocelli  are  designed  chiefly  for 
observing  near  objects,  and  the  fact  of  their 
existing,  as  just  stated,  in  many  insects  in 
which  the  cornea  of  the  proper  eyes  are  ex- 
ceedingly large,  seems  to  favour  this  opinion. 
Their  presence,  as  in  Hymenoptera,  is  most  re- 
markable in  the  males,  as  in  the  male  Empidte, 
in  which,  although  the  proper  corneae  cover 
the  whole  surface  of  the  head,  yet  there  are 
also  three  large  ocelli  situated  in  the  trian- 
gular space  immediately  behind  the  corneae, 
and  even  elevated  upon  a  pedicle.  In  Tabanus 
there  appears  at  first  to  be  only  a  single  ocellus, 
situated  in  the  median  line  between  the  corneae 
at  the  anterior  part  of  the  head  ;  but  on  close 
inspection  it  is  found  to  be  divided  into  two  by 
the  longitudinal  suture  which  passes  through  it, 
so  that  the  two  ocelli  from  their  close  approxi- 
mation appear  but  as  one. 

In  the  organization  of  the  mouth  the  same 
parts  exist  in  Diptera  as  in  the  preceding 
orders,  but  modified  in  form  to  adapt  them  to 
a  different  mode  of  use.    Thus  we  have  seen 
that  in  Hymenoptera  and  Lepidoptera  it  was 
simply  necessary  that  the  parts  should  be 
elongated,  to  enable  the  insects  to  obtain  the 
liquid  food  already  prepared  for  them ;  but  in 
Diptera  not  merely  was  it  necessary  that  this 
should  be  the  case,  but  also  that  their  form 
should  be  materially  altered,  to  adapt  them  to 
a  mode  of  employment  different  from  that  of 
analogous  parts  in  other  insects.    Thus  in 
Tubunida,  the  labrum  and  mandibles  are  used 
like  lancets,  to  pierce  the  integuments  of  other 
animals,  before  these  parasitic  blood-suckers 
can  obtain  the  living  fluid  they  are  in  quest  of ; 
while  in  other  species,  as  in  Eristalis  floreus, 
(fig-  379,)  which  subsists  both  on  the  pollen 
and  honey  of  flowers,  the  mandibles  and 
maxilla?  are  employed  to  scrape  off  the  pollen 
from  the  anthers,  before  it  is  conveyed  along 
the  tube  formed  by  the  united  parts  of  the 
mouth  to  the  pharynx.    In  other  Diptera,  of 
which  the  food  is  entirely  fluid  and  easily  ac- 
cessible, as  in  the  common  house-flies,  Muscida, 
all  the  parts  of  the  mouth  are  soft  and  fleshy, 
and  simply  adapted  to  form  a  sucking  tube, 
which  in  a  state  of  rest  is  closely  folded  up  in 
a  deep  fissure,  on  the  under  surface  of  the 
head,  formed  by  the  two  sides  of  the  clypeus. 

*  Elements  of  Physiology,  by  J.  Muller,  M.D., 
(translated  by  W.  Baly,  M.D.,  part  v.  p.  1116, 


Fig.  379. 


Mouth  or  proboscis  of  Eristalis  floreus. 

d,  front  beneath  the  clypeus  ;  e,  labrum  ;  f,  man- 
dible ;  9,  maxilla  and  palpus  ;  i,  labium  ;  i*,  labium 
dilated  ;  inner  surface  of  paraglossa  ;  the 
rows  of  hairs  on  the  inner  surface  ;  I,  ligula  ;  m, 
cardo  and  submentum. 

On  the  other  hand,  in  the  (Estrida,  which,  as 
we  have  seen  in  the  Phryganidte,  Bombycidce, 
and  others  that  take  no  food  in  their  perfect 
state,  all  the  parts  of  the  mouth  have  entirely 
disappeared.  It  is  in  Tabanida  that  the  oral  or- 
gans of  Diptera  are  most  perfectly  developed, 
and  approach  nearest  to  those  of  Hymenoptera, 
and  are  easily  distinguished ;  while  in  the  soft 
fleshy  proboscis  of  Muscida  their  identification 
is  a  matter  of  considerable  difficulty.  Ac- 
cording to  Savigny*  the  proboscis  of  Diptera 
is  formed  solely  by  the  labium,  or  under-lip, 
divided  into  its  primary  parts  as  in  other  in- 
sects ;  while  Desvoidsyf  on  the  contrary  be- 
lieves that  it  is  not  formed  by  the  labium,  but, 
as  in  Lepidoptera,  solely  by  the  maxillae.  Now 
we  have  seen,  that  although  in  Lepidoptera 
the  maxillae  alone  form  the  tubular  mouth  or 
proboscis,  yet  that  in  Hymenoptera  the  labium 
is  the  part  chiefly  employed  in  gathering  the 
honey,  which  is  conveyed  to  the  cavity  of  the 
mouth  and  pharynx  only  by  the  maxillae  as- 
sisting to  form  a  tube  of  which  the  labium 
constitutes  the  inferior  portion.  Analogy  there- 
fore would  lead  us  to  expect  a  somewhat  si- 
milar conformation  of  the  mouth  in  Diptera, 
and  that  since  these  insects  have  either  to  pierce 
the  coverings  of  other  animals  before  they  can 
obtain  their  food,  or  to  gather  their  nourish- 
ment by  employing  the  proboscis  as  a  pre- 
hensile organ,  the  maxillae  may  fairly  be  sup- 
posed to  enter  into  its  formation,  and  accord- 
ingly we  find,  on  a  careful  examination,  that 
such  is  actually  the  case,  and  that  the  proboscis 
is  formed  of  the  maxillae  and  labium  united. 
We  have  been  led  to  this  conclusion  by  a  care- 

*  Mem.  sur  les  Anim.  sans  vertebres. 

t  Essai  sur  les  Myodaires,  par  le  Docteur  J.  B. 
Robineau  Desvoidsy,  4to,  1830,  torn.  x.  Me- 
moires  de  l'lnstitut  de  France. 


904 


INSECTA. 


ful  examination  and  comparison  of  the  parts  of 
the  mouth  in  Volucella,  Echinomyia,and  Musca, 
with  those  in  Tabanida  and  Asilidaz.  To  com- 
mence our  observations  with  the  most  perfect 
form  of  mouth,  we  find  in  Tabanida:  that  the 
labrum  is  an  elongated,  acute,  corneous  plate, 
freely  articulated  to  the  margin  of  the  clypeus, 
and  marked  along  its  middle  line  with  a 
raphe.  It  is  concave  on  its  under  surface,  and 
is  as  long  as  the  mandibles  and  maxilla,  which 
it  partially  covers,  and  somewhat  resembles  in 
appearance.  In  Culex  it  is  longer  than  these 
parts,  and  is  more  sharp- pointed.  In  Asilus 
crabroniformis  it  is  much  shorter  than  either 
the  mandibles  or  maxillae.  It  is  narrow,  tri- 
angular, and  rounded  at  its  apex,  with  a  slight 
indentation,  and  is  not  used  by  the  insect  as  a 
lancet,  as  in  the  preceding  instances,  but  merely 
forms  the  anterior  covering  of  the  mouth.  In 
Eristalis  Jioreus  (e)  it  is  a  short  mitre-shaped 
plate,  which  covers  the  base  of  the  mandibles 
and  maxilla?,  and  articulates  freely  with  the 
clypeus.  In  Volucella  bombylqns  it  is  reduced 
to  a  very  narrow  short  plate,  articulated  with, 
and,  in  a  state  of  rest,  inflected  beneath  a  small 
triangular  one,  which  is  inserted  into  a  deep 
cleft  of  the  clypeus,  and  which  appears  to  be 
the  proper  analogue  of  the  clypeus  anterior. 
In  Rhingia  rostrata  it  has  almost  entirely  dis- 
appeared, so  likewise  has  the  part  that  we 
are  inclined  to  regard  as  the  clypeus  anterior, 
which  is  inserted  into  the  cleft  at  the  extremity 
of  the  elongated  rostriform  anterior  part  of  the 
head.  In  Echinomyia  it  still  exists  as  a  very 
narrow  corneous  plate  articulated  with  the 
clypeus,  inflected  beneath  the  head  when  the 
proboscis  is  retracted,  but  forming  the  anterior 
portion  of  its  base  when  the  organ  is  extended. 
In  Musca  it  has  entirely  disappeared  as  a  dis- 
tinct piece,  but  seems  to  have  become  the 
union  of  two  corneous  plates,  which  together 
form  an  arch  on  the  front  of  the  mouth,  or  base 
of  the  proboscis,  and  represent  the  mandibles, 
the  intervening  space  being  covered  by  a  strong 
membrane.  The  mandibles,  which  had  almost 
disappeared  in  Lepidoptera,  still  exist  in  the 
rapacious  Diptera,  and  in  those  which  pierce 
the  skin  of  other  animals.  In  Tabanus  they 
are  long,  and  somewhat  lancet-shaped  plates, 
situated  immediately  beneath  the  labrum. 
They  are  slightly  curved,  like  a  cutlass,  and 
sharp-pointed.  They  are  not  employed  in 
crushing  or  cutting  solid  food,  as  in  proper 
mandibulated  insects,  but  in  puncturing  or 
piercing  with  a  horizontal  motion  from  be- 
hind forwards,  and  not  from  side  to  side. 
In  this  genus,  howevet,  their  motion  appears 
to  be  not  simply  that  of  thrusting  or  pier- 
cing, but  also  that  of  cutting  vertically  with 
a  sweeping  stroke,  like  the  lancets  of  a  cup- 
ping instrument,  for  which  motion  they  are 
well  adapted  by  their  cotyloid  form  of  arti- 
culation. In  the  common  gnat,  Culex,  they 
are  very  slender,  and  sharp-pointed.  The  pain 
occasioned  by  the  piercing,  or  supposed  biting 
of  the  insect,  arises  from  the.  act  of  thrusting 
these  instruments  through  the  skin.  In  these 
instances  the  mandibles  are  equal  in  length  to 


the  other  parts  of  the  mouth,  but  in  Eristalis, 
in  which  they  have  still  the  same  acute  form, 
they  are  somewhat  shorter.  In  the  rapacious 
Asilus  crabroniformis  the  mandibles  of  the  two 
sides  are  united  to  form  a  single,  strong,  sharp- 
pointed  barb,  very  acute,  and  ciliated  at  the 
apex  on  its  upper  surface,  and  projecting  be- 
yond the  other  parts  of  the  mouth.  In  Rhingia 
rostrata  they  still  exist  as  delicate  elongated 
setae,  approximated  at  their  apex ;  but  in  the 
neighbouring  genus,  Volucella,  we  have  been 
unable  to  detect  them,  except  as  two  flat  plates, 
approximated  to  the  anterior  part  of  what  we 
regard  the  proper  cardines  of  the  maxillae  and 
labrum,  and  by  which  the  parts  of  the  mouth 
are  thrust  forwards.  In  Echinomyia  the  man- 
dibles have  also  disappeared  as  distinct  organs, 
and  seem  to  be  united  to  the  base  of  the  car- 
dines  within  the  mouth,  as  in  Volucella,  and 
there  is  a  similar  condition  of  these  parts  in 
Musca,  in  each  instance  the  anterior  part  of  the 
mouth  being  covered  by  a  strong  membrane, 
which  supplies  the  place  of  the  horny  labrum. 
The  lingua  exists  in  most  Diptera.  It  is 
largely  developed  in  Tabanus,  in  which  it  is  a 
single  horny  seta  situated  between  the  man- 
dibles in  the  centre  of  the  mouth.  It  was  dis- 
tinctly pointed  out  by  Savigny,  and  subse- 
quently by  Latreille.  It  was  called  by  the 
former  the  hypopharynx.  The  maxilla:,  like  the 
mandibles,  undergo  a  gradual  diminution  of 
size.  In  Tabanus  they  are  straight,  and  as  long 
as  the  mandibles,  but  narrower  and  less  acute. 
In  Asilus,  (fig.  380, g)  they  are  very  acute  and 


Fig.  380. 


Under  surface  of  the  mouth  of  Asilus  crabroniformis. 

m,  submcntuin  -,  1,  cardo  ;  2,  stipes  ;  3,  palpifer  ; 
5,  lacinia  ;  h,  maxillary  palpus  ;  I,  mcntum  ; 
i,  ligula. 


INSECTA. 


905 


strong,  with  sharp  cutting  edges.  They  are  short- 
er and  narrower  than  the  mandibles,  and  are 
usually  inclosed  within  the  sheath  or  proboscis 
formed  by  the  labium.  In  this  family  some  of 
their  primary  parts  are  easily  distinguished. 
Thus  the  blades  (5)  that  lie  within  the  sheath 
of  the  labium,  are  the  true  laciniae  in  other 
insects.  These  are  articulated  at  their  base 
with  the  palpifer  (3),  a  small  triangular  plate, 
which  bears  the  maxillary  palpus  and  is  situ- 
ated most  externally, — and  also  with  a  broad 
squamous  plate  (2),  which  is  united  at  its  base 
to  its  fellow  of  the  opposite  side,  and  appears 
to  be  analogous  to  the  stipes  and  cardo(l) 
united.  This  plate,  with  its  fellow,  forms  the 
anterior  boundary  of  the  throat,  and  is  closely 
united  to  the  proper  gula  that  bounds  the 
anterior  margin  of  the  occipital  foramen.  The 
muscles  attached  to  the  posterior  margin  of  the 
mentum  and  submentum  pass  over  this  plate 
to  be  attached,  one  set  to  the  anterior  margin  of 
the  gula,  and  the  other  to  the  posterior.  In 
Volucella  bombylans  the  maxillae  have  lost 
much  of  their  importance,  but  are  still  easily 
distinguished,  and,  with  the  other  parts  of  the 
mouth,  are  beginning  to  be  merged  in  the 
united  fleshy  proboscis.  The  cardines,  upon 
which  all  the  motions  of  flexion  and  extension 
in  this  kind  of  mouth  depend,  are  very  largely 
developed.  They  are  two  elongated  plates, 
approximated  to  each  other  along  their  inner 
margins,  and  to  two  triangular  plates,  the  re- 
mains of  the  mandibles,  at  their  anterior  and 
lateral.  The  cardines  thus  form  the  posterior, 
or  basilar  part  of  the  proboscis,  and  the  plates 
which,  from  being  articulated  within  the 
margin  of  the  clypeus  posterior,  we  regard  as 
analogous  to  the  mandibles,  the  lateral.  At 
their  inferior  portion,  which  forms  the  joint  or 
elbow  of  the  proboscis,  the  cardines  are  freely 
articulated  with  the  stipes,  which  is  a  short 
plate  not  easily  distinguished  from  a  part  of  the 
mandible  with  which  it  is  also  in  apposition. 
Between  the  stipes  and  cardo  is  a  short  trian- 
gular plate,  the  palpiger,  rounded  at  its  most 
inferior  part,  and,  with  its  fellow  of  the  oppo- 
site side,  assisting  to  form  the  elbow  or  joint  of 
the  proboscis.  The  maxillary  palpus,  which 
aises  from  its  external  border,  is  long  and 
slender,  and  appears  to  be  formed  of  three 
short  joints  and  one  very  long  one.  At  the 
inner  and  anterior  margin  of  the  palpifer  and 
stipes  is  articulated  the  laciniu,  which,  as  in 
Asilus,  is  of  considerable  length.  It  is  inte- 
resting to  remark,  that  in  this  insect,  which  is 
parasitic  in  its  habits,  insinuating  itself  into 
the  nests  of  humble-bees  to  deposit  its  eggs, 
the  mandibles,  as  just  shewn,  are  atrophied,  and 
the  two  laciniae  of  the  maxillae,  although  dis- 
tinct from  each  other,  are  approximated  in  the 
middle  line  to  form  the  anterior  or  upper  sur- 
face of  the  tube  to  the  mouth,  as  in  Hymen- 
optera,  the  sides  and  lower  portion  of  the  tube 
being  formed  by  the  labium,  and  all  the  motions 
of  extension  and  flexion  in  the  proboscis  being 
dependent  upon  the  cardines,  as  we  have  before 
seen  in  Ilymenoptera.  In  this  genus  there- 
fore we  discover  one  of  the  transitionary  forms 


of  mouth  from  that  of  the  blood-sucking  in- 
sects to  those  of  the  more  omnivorous  feeders, 
all  the  parts  of  the  mouth  being  less  and  less 
distinct  in  proportion  as  the  act  of  taking  food 
is  less  complicated.  Thus  we  have  seen  that 
in  Tabanus  distinct  mandibles  are  required  to 
pierce  the  skin  of  an  animal,  before  the  food  is 
accessible;  but  in  the  Muscida,  whose  fluid 
aliment  is  every  where  present,  a  complicated 
form  of  mouth  is  unnecessary,  and  accordingly 
we  find  it  reduced  to  a  simple  sucking  tube. 
In  Eristulis  the  maxilla  are  present,  as  in 
Asilus  and  Volucella,  as  also  are  their  palpi, 
which  are  nearly  equal  to  them  in  length.  In 
Ec/iinomi/ia  they  are  less  distinct  than  in  Volu- 
cella. The  anterior  part  of  the  proboscis  at  its 
base  is  formed  simply  by  a  broad  membrane 
united  to  the  anterior  margin  of  the  atrophied 
mandibles,  while  the  lacinia?,  which  were  dis- 
tinct in  the  preceding  genera,  are  united  in 
this  genus  to  form  the  front  of  a  lower  portion 
of  the  organ.  That  this  union  has  taken 
place  is  shewn  in  the  presence  of  the  maxillary 
palpi,  which  invariably  exist  in  Dipterous 
insects.  In  all  the  Muscida  the  palpi  arise 
from  a  distinct  palpifer,  which  appears  to  be 
connected  with  a  proper  stipes,  but  the  re- 
maining parts  are  not  easily  distinguished. 
It  seems  evident,  however,  that  at  least  the 
basilar  portion  of  the  proboscis  is  formed  by 
the  union  of  the  laciniae  above  and  the  labium 
below,  as  in  Hymenoptera,  and  that  the  la- 
bium forms  the  chief  portion  of  the  organ, 
contrary  to  the  opinion  of  Desvoidsy,  who 
believed  that  the  proboscis  of  Diptera  was 
formed  of  the  maxillae  alone,  and  to  that  of 
Savigny,  who  regarded  the  proboscis  as  formed 
only  of  the  labium.  The  principle  therefore 
upon  which  the  proboscis  of  Dipteia  is  con- 
structed, is  precisely  analogous  to  that  of 
Hymenoptera,  but  there  are  important  diffe- 
rences in  the  form  of  similar  parts  in  the  two 
orders.  The  labium  includes  the  same  primary 
parts  as  in  Hymenoptera,  but  the  labial  palpi 
are  almost  invariably  absent.  The  submentum 
is  usually  indistinct.  In  Asilus  the  p'art  we 
regard  as  such  is  a  small  triangular  plate,  (m,) 
distinguished  only  when  the  parts  are  examined 
by  transmitted  light.  It  is  situated  between 
the  anterior  portions  of  the  two  cardines.  In 
Volucella  it  is  that  part  of  the  proboscis  which 
is  nearest  to  the  cardines,  close  to  the  articu- 
lation. In  Culex,  in  which  the  cardines  are 
short,  it  is  situated  very  close  to  the  under 
surface  of  the  head  ;  in  other  Diptera  it  is  fre- 
quently very  indistinct.  The  mentum  on  the 
contrary  is  always  a  conspicuous  part.  In 
Asilus  it  is  the  broadest  part  of  the  proboscis  (/). 
It  is  a  strong  horny  plate,  deeply  channelled  on 
its  upper  surface  to  form  a  canal  to  the  mouth, 
and  receive  within  it  the  mandibles  and  max- 
illae. It  is  articulated  with  the  ligula,  or  ex- 
tremity of  the  proboscis  (i),  which  is  distinctly 
formed  of  two  halves  approximated  together, 
and  narrowest  at  the  apex,  with  three  slight 
lateral  dilatations.  In  Volucella  the  mentum 
in  like  manner  is  a  strong  deeply  channelled 
plate,  covered  above  by  the  laciniae.    There  is 


* 


906 


INSECTA. 


a  similar  structure  of  the  proboscis  in  Eristalis. 
The  subraentum  is  the  part  in  which  the  flexion 
of  the  organ  takes  place ;  the  mentum,  as  in 
the  preceding  instances,  is  a  strong  horny  plate, 
almost  closed  on  its  upper  as  well  as  its  under 
surface,  and  the  ligula  is  horny,  but  terminated 
by  soft  dilatable  lips.  The  ligula  is  always 
articulated  by  a  distinct  joint  with  the  mentum, 
and  appears  to  be  constantly  present  in  this 
order.  In  Asilus,  as  we  have  just  remarked, 
it  is  strong  and  corneous,  but  in  the  less  rapa- 
cious insects,  as  in  Eristalis,  and  the  Muscida, 
it  is  terminated  by  two  dilated  fleshy  lips, 
which  we  regard  as  the  analogues  of  the 
paraglossa  (Jig.  379,  *  i.)  In  Tabanus  these  are 
exceedingly  large  and  broad,  and  are  widely 
expanded  to  encompass  the  wound  made  by 
the  insect  with  its  lancet-like  mandibles  in  the 
skin  of  the  animal  it  attacks.  The  structure 
of  these  paraglossae  is  curious.  On  their  outer 
surface  they  are  fleshy  and  muscular,  to  fit 
them  to  be  employed  as  prehensile  organs, 
while  on  their  inner  they  are  more  soft  and 
delicate,  but  thickly  covered  with  rows  of  very 
minute  stiff  hairs  (***  i)  directed  a  little  back- 
wards, and  arranged  closely  together  like  the 
teeth  of  a  comb.  There  are  very  many  rows 
of  these  hairs  on  each  of  the  paraglossae,  and 
from  their  being  all  arranged  in  a  similar  di- 
rection are  easily  employed  by  the  insect  in 
scraping  or  tearing  delicate  surfaces.  It  is  by 
means  of  this  curious  structure  that  the  busy 
house-fly  often  occasions  much  mischief  to  the 
covers  of  our  books  by  scraping  off  the  albu- 
minous polish,  and  leaving  traces  of  its  depre- 
dations in  the  soiled  and  spotted  appearance 
which  it  occasions  on  them.  It  is  by  means  of 
these  also  that  it  teases  us  in  the  heat  of  summer 
when  it  alights  on  the  hand  or  face  to  sip  the 
perspiration  as  it  exudes  from  and  is  condensed 
upon  the  skin.  The  manner  in  which  the 
fluid  ascends  the  proboscis  is  similar  to  that  of 
its  ascent  in  other  Haustellata,  it  being  de- 
pendent partly  upon  the  sucking  action  exerted 
by  the  application  of  the  proboscis,  assisted  by 
the  muscular  action  of  the  paraglossae,  as  any  one 
may  readily  convince  himself  on  watching  the 
motion  of  the  parts  in  the  common  house-fly, 
when  sipping  a  drop  of  fluid,  or  moistening 
the  stolen  grain  of  chrystallized  sugar  between 
its  paraglossae. 

The  palpi  yet  remain  to  be  noticed.  Those 
of  the  maxillae  appear  to  be  constant  throughout 
the  whole  order.  In  Culex  they  are  very  con- 
spicuous parts,  covered  with  hairs  and  as  long 
as  the  proboscis ;  they  are  formed  of  three  short 
basial  joints  and  three  very  long  ones,  the  fourth 
joint  being  more  than  twice  the  length  of  either 
of  the  others.  In  Tipula  and  Empis  they  are 
also  six-jointed,  but  of  moderate  length.  In 
Tabanus  also  they  are  very  conspicuous,  and 
appear  to  be  formed  of  two  short  and  one  very 
long  joint  densely  covered  with  hairs,  and  serve 
as  a  cover  to  the  base  of  the  proboscis.  In 
Asilus  they  are  short,  three-jointed,  and  slightly 
hairy  (Jig.  380,  h ),  and  they  are  equally  con- 
spicuous in  most  of  the  Muscida  and  Syrphida, 
in  which  they  are  formed  in  general  of  two  short 


joints  and  one  very  long  one.  In  the  common 
Musca  they  are  long  and  club-shaped,  but  in 
Eristalis  (Jig.  379,  g,  h )  and  Volucella  they  are 
long,  slender,  and  sometimes  covered  with  hairs. 
The  labial  palpi  do  not  appear  to  exist  in 
Diptera.  Savigny  believed  that  he  had  ob- 
served at  the  base  of  the  ligula  in  Tabanus  a 
pilose  excrescence  which  he  considered  the 
analogue  of  the  labial  palpi ;  but  although,  as 
Mr.  Newman  has  remarked,  the  spot  which 
Savigny  pointed  out  is  exactly  that  at  which 
they  ought  to  be  situated  if  they  really  did 
exist,  we  have  been  unable  to  detect  them  or 
to  confirm  his  opinion. 

In  Homaloptera  the  head  resembles  that  of 
Diptera.  It  is  rounded  but  flattened  on  its 
upper  surface,  and  is  so  closely  approximated 
to  the  anterior  margin  of  the  prothorax  into  a 
notch  in  which  it  is  inserted,  as  to  appear  as  if 
separated  from  it  only  by  a  suture.  All  the 
primary  parts  found  in  the  head  in  other  insects 
appear  to  be  developed  in  some  species  of  this 
order.  Thus  the  epicranium  in  Oxypterum  is 
broad,  distinct,  and  channelled  along  the 
median  line  into  a  deep  groove  (Jig.  381,  b ), 

Fig.  381. 


31 


The  upper  and  under  surface  of  the  head  in 
Oxypterum. 

b,  epicranium  ;  c,  cornea ;  d,  clypeus  posterior  ; 
d*,  clypeus  anterior ;  e,  labrum ;  /,  undeveloped 
mandibles;  g,  maxilla;  i,  labium;  *,  lingua. 


INSECTA. 


907 


and  the  triangular  suture,  particularly  the  ante- 
rior portion,  which  divides  the  epicranium 
from  the  clypeus  posterior  (d),  is  very  distinct. 
At  the  anterior  external  angle  of  this  part  of 
the  clypeus,  as  in  Coleoptera,  are  situated  the 
antenna  (a),  two  short  and  thick  porrected 
organs,  covered  with  a  few  long  hairs,  and 
which,  although  apparently  composed  each  of 
two  joints,  appear  to  be  rigid  and  motionless. 
Immediately  anterior  to  the  clypeus  posterior, 
and  divided  from  it  by  a  distinct  suture,  is  a 
short  lunated  plate  (d*),  the  clypeus  anterior. 
The  cornua  of  this  part  are  extended  laterally 
at  the  sides  of  the  mouth,  and  are  continuous 
with  a  portion  of  the  under  surface  of  the  head 
(,/')  that  bounds  the  labium.    Between  the  two 
cornua  of  the  upper  surface  is  extended  a  strong 
and  somewhat  horny  membrane  (e),  the  proper 
labrum,  which  is  continuous  with  a  similar 
membrane  on  the  under  surface  (<),  the  labium, 
which  thus  forms  the  orifice  of  the  mouth,  the 
parts  of  which  do  not  appear  to  have  been 
sufficiently  examined  in  this  order.  Thus, 
although  the  entrance  to  the  mouth  is  indicated 
by  a  distinctly  marked  labrum  and  labium, 
scarcely  more  developed  than  in  Coleoptera, 
the  habits  of  the  insect  require  that  it  should 
also  be  furnished  with  a  strong  sucking  tube. 
Accordingly  we  find  that  within  this  mem- 
branous mouth  are  situated  two  curved  horny 
plates,  a  little  convex  on  their  external,  but 
concave  on  their  internal  surface,  and  capable 
of  being  protruded  to  some  distance.  They  are 
directed  downwards,  and  when  approximated 
form  a  tube  analogous  to  that  of  Lepidoptera. 
These  parts  have  been  described  by  Curtis  as 
the  maxilla:  (g),  of  which  they  seem  to  be  the 
proper  analogues,  so  that  in  the  Ilomaloptera 
the  maxillae  form  the  sheath  or  outer  part  of  the 
sucking  tube.    At  the  base  of  these  parts, 
within  the  cavity  of  the  mouth,  are  two  horny 
margins  fringed  with  dark  hairs,  which  are 
probably  rudimental  maxillary  palpi.    In  the 
centre  of  the  mouth  is  situated  an  elongated 
slender  organ  (*),  which  is  folded  at  an  angle 
like  the  proboscis  of  Diptera,  but  is  retractile 
within  the  mouth,  and  extends  backwards  to 
the  entrance  to  the  oesophagus.    It  consists  of 
three  parts,  an  inferior  one  which  is  strong, 
horny,  and  forms  a  groove  or  canal,  the  upper 
surface  of  which  is  covered  by  another  smaller 
piece,  and  the  two  inclose  between  them  a 
third  setiform  organ.  Upon  the  precise  nature  of 
these  parts  we  do  not  offer  a  positive  opinion ; 
the  inferior  one,  which  is  continuous  with  the 
inflected  portion  of  the  labium,  seems  to  repre- 
sent an  elongated  portion  of  that  organ,  and 
the  middle  one  probably  is  the  lingua,  in  which 
case  the  upper  one  would  answer  to  a  similarly 
elongated  portion  of  the  labrum. 

The  under  surface  of  the  head  is  divided  by 
a  deep  incisure  anteriorly,  the  margins  of  which 
are  covered  with  stiff  hairs  and  form  the  lateral 
boundary  of  the  mouth.  The  mention  (/), 
described  as  such  by  Curtis,  is  a  strong  convex 
plate,  divided  also  at  its  anterior  part  by  a  con- 
tinuation of  the  incisure  just  noticed.  The 
cornea  (c),  of  an  oval  convex  shape,  are  situated 
more  on  the  upper  than  on  the  lateral  part  of 


the  head,  but  the  ocelli  in  this  insect  are  entirely 
wanting,  unless  we  regard  as  a  large  ocellus 
a  convex  plate  situated  in  the  middle  of  the 
most  posterior  part  of  the  epicranium  (6*). 
In  the  other  genera  of  this  order,  as  in  Hamo- 
bora,  the  head  is  more  orbicular  and  less  flat- 
tened ;  the  epicranium  is  broad  and  distinct, 
and  the  suture  between  this  part  and  the 
clypeus  posterior  is  strongly  marked.  In 
Melophagus,  the  tick  or  sheep-louse,  the  maxillae 
are  of  considerable  length,  and  the  retractile 
portion  of  the  labium  inclosing  the  lingua  is  of 
considerable  strength.  The  ocelli  are  present,  in- 
serted in  little  excavations  in  Hamobora,  but  ab- 
sent in  Melophagus.  In  Ni/cteribida  the  head 
offers  a  most  anomalous  condition  of  parts,  its 
form  being,  as  described  by  Latreille,  that  of  a 
reversed  cone.  We  have  had  no  opportu- 
nities of  examining  for  ourselves  either  the  head 
or  parts  of  the  mouth,  which,  according  to 
Messrs.  Curtis*  and  Westwood,t  are  styliform, 
and  analogous  to  those  of  Hippobosca. 

In  Aphaniptera  the  head  is  compressed 
from  side  to  side,  but  we  have  not  yet  identified 
its  primary  parts.  Its  chief  characteristics  are 
its  extreme  narrowness,  the  situation  of  its 
antenna;,  and  the  peculiarity  of  its  organs  of 
vision,  the  corneas  of  the  proper  eyes  being 
each  simple  and  not  compound  as  in  other 
insects.  The  mouth  is  formed  upon  the  same 
general  principles  as  in  the  blood-sucking 
Diptera,  being  composed  of  six  primary  parts 
adapted  for  piercing  the  skin,  and  occasioning 
the  pain  which  distinguishes  the  puncturing  of 
these  troublesome  insects. 

In  Aptera,  all  of  which,  like  the  insects  of 
the  two  preceding  orders,  are  parasitic  upon 
the  bodies  of  other  animals,  the  mouth  in  one 
family,  the  true  Pediculida,  is  formed  for  suck- 
ing, but  in  the  other,  the  Nirmida,  it  is  dis- 
tinctly mandibulated,  and  approaches  the  usual 
type  of  mandibulated  insects. 

In  Hemiptera  the  head  is  often  flattened  and 
somewhat  triangular,  and  the  mouth  is  rostri- 
form  as  in  some  of  the  Diptera,  but  the  sheath 
of  the  organ  is  formed  entirely  by  the  labium 
(Jig.  382,  k ).  The  corneae  are  usually  very 
prominent,  and  are  placed  at  the  posterior 
angles  of  the  head.  The  epicranium  is  distinct, 
but  its  occipital  portion  is  sunk  into  a  notch  in 
the  prothorax.  The  ocelli  are  usually  two  in 
number,  placed  on  the  most  posterior  part  of 
the  epicranium,  and  are  constant  throughout 
the  order  in  the  perfect  state,  but  are  not  deve- 
loped in  the  larva  or  pupa.  The  division  of 
the  head  into  its  primary  parts  is  very  distinct 
in  some  genera.  In  Coreus  marginatus  the 
epicranial  suture  is  strongly  marked  along  the 
middle  line  as  far  as  the  space  between  the 
corneae,  where  it  joins  the  triangular  suture  which 
passes  outwards  immediately  behind  the  inser- 
tion of  the  antenna?,  bounding  the  clypeus 
posterior.  In  some  specimens,  but  more  par- 
ticularly in  the  pupa,  a  faint  longitudinal  suture 
extends  forwards  over  the  clypeus  as  far  as  the 

*  British  Entomology,  pi.  277. 
t  On  Nycteribia,  in  Transactions  of  the  Zoologi- 
cal Society  of  London,  vol.  i.  p.  279. 


908 


INSECTA. 


Fig.  382. 


Head  of  Pentatoma  rufipes  ( Savigny ). 

most  anterior  portion  of  the  front  of  the  head, 
where  it  joins  with  a  second  triangular  suture 
which  passes  outwards  on  each  side  anterior  to 
the  insertion  of  the  antenna,  and  thus  divides 
the  clypeus  anterior  from  the  posterior.  The 
proper  triangular  suture  between  the  epicranium 
and  clypeus  passes  backwards  from  behind  the 
insertion  of  the  antennas  along  the  sides  of  the 
head  as  far  as  the  margin  of  the  cornea,  thus 
clearly  indicating  the  extent  of  the  epicranial 
region,  as  in  Coleoptera.  The  clypeus  anterior 
is  distinctly  marked  at  the  front  of  the  head  (d) 
as  a  narrow  elongated  plate,  a  little  widened  at 
its  lower  portion,  where  it  is  articulated  with  the 
labrum  (e),  which  is  narrow,  lengthened,  and 
ends  in  a  point,  and  covers  the  front  of  the 
proboscis  (A;),  which  is  formed  of  four  joints 
or  articulations,  and  is  believed  by  Savigny  to 
represent  the  true  labrum.  This  part,  which, 
in  a  state  of  rest,  is  concealed  beneath  the 
under  surface  of  the  head  and  prothorax,  forms 
a  cylindrical  tube  throughout  nearly  its  whole 
length,  from  its  apex  to  its  base,  where  it  is 
covered  by  the  labrum.  It  incloses  four  dis- 
tinct sets,  which  have  been  shewn  by  Savigny 
to  be  the  proper  mandibles  and  maxillae.  We 
are  satisfied  of  the  correctness  of  this  opinion 
from  our  own  examination  of  these  parts,  the 
insertion  of  the  muscles  belonging  to  them 
being  in  the  basilar  portion  of  the  head,  as  in 
all  the  preceding  orders.  But  it  is  in  Reduvius 
that  the  parts  of  the  head  are  most  distinctly 
marked.  The  occipital  portion  is  so  much 
elongated  backwards  as  to  form  a  very  distinct 
neck,  narrower  considerably  than  the  other 
parts  of  the  head,  and  the  corneas  are  large  and 
protuberant  and  stand  out  from  its  broadest 
part,  while  the  ocelli,  two  in  number,  are  also 
exceedingly  large  and  are  placed  on  short 
pedicles  almost  on  the  constricted  neck-like 
part  of  the  epicranium,  far  behind  the  cornea, 
and  with  their  axis  directed  posteriorly.  Be- 
tween this  portion  of  the  head  and  that  which 
contains  the  true  corneae  is  a  deep  transverse 
impression,  which  seems  to  indicate  that  the 
corneas  and  ocelli  are  derived  from  distinct  seg- 
ments. But  one  of  the  most  marked  charac- 
teristics of  the  epicranium  in  this  insect  is  the 
existence  of  a  triangular  elevation  or  ridge, 


which  commences  in  the  usual  situation  of  the 
suture  in  the  middle  line  between  the  corneas, 
and  extending  outwards  marks  the  course  of 
the  antennae.  The  posterior  margin  of  this 
ridge  is  in  the  usual  direction  of  the  triangular 
suture,  posterior  to  the  insertion  of  the  antennae. 
Anterior  to  this  is  a  lozenge-shaped  plate,  the 
clypeus  posterior,  which  is  elevated  along  its 
middle  line,  and  which  is  continuous  with  a 
similar  elevation  on  the  clypeus  anterior.  The 
labrum  is  short,  and  terminates"  in  a  triangular 
process,  that  covers  the  base  of  the  proboscis 
as  in  the  preceding  species.  We  have  thus 
five  clearly  indicated  segments  in  the  head  of  a 
perfect  insect, — the  occipito-basilar  segment 
bearing  the  ocelli,  the  proper  epicranial  with 
the  corneas  and  antennae,  the  two  clypeal,  and 
the  labial.  The  proboscis  consists,  as  in 
Coreus,  of  four  distinct  articulations,  which 
form  the  labium,  and  correspond  to  the  seg- 
ments of  the  upper  surface  of  the  head,  but 
which  are  extended  forwards  and  form  a  sheath 
for  the  setiform  mandibles  and  maxillae.  In 
the  Hydrometrida,  which  connect  the  terrestrial 
with  the  aquatic  Hemiptera,  the  head  is  elon- 
gated forwards,  and  the  corneas,  which  are  large 
and  kidney-shaped,  are  very  protuberant.  In 
Gerris  pallidum  the  epicranial  region  is  short, 
but  the  suture  is  still  very  distinct.  It  divides 
as  usual  at  a  point  opposite  to  the  middle  of 
the  corneas,  and  passes  outwards  to  their  ante- 
rior margin.  The  clypeus  posterior  is  broad 
and  lengthened,  and  seems  to  have  become 
united  with  the  anterior,  and  the  antennas  are 
moved  forwards  to  the  base  of  the  proboscis. 
The  Nepida  have  a  form  of  head  similar  to 
that  of  the  Hydrometridas,  but  the  epicranial 
region  (Jig.  383,  d)  is  of  greater  extent.  In 


Fig.  383. 


Upper  and  under  surface  of  the  head  of  Nepa  cinerea 
(  Savigny.) 

a,  occiput ;  b,  epicranium ;  c,  cornea ;  d,  cly- 
peus posterior  ;  e,  labrum  ;f,  mandibles  ;  g,  maxil- 
lae ;  i,  labium ;  *,  lingua. 

the  figure  which  we  have  copied  from  Savigny 
the  parts  of  the  head  are  not  distinguished, 
but  they  are  distinct  in  the  insect.  The  epicra- 
nial suture,  the  proper  guide  to  a  correct  deter- 
mination of  the  primary  parts  of  the  head  in 
every  species,  bounds  the  corneas  anteriorly  and 


INSECTA. 


909 


the  clypeus  posteriorly,  which  is  reduced  to  a 
small  triangular  plate  (rf)  with  its  apex  directed 
backwards.  It  is  divided  by  a  transverse  suture 
from  the  clypeus  anterior,  which  forms  a  chief 
part  of  the  front  of  the  head.  The  labium  (e), 
as  in  the  preceding  species,  is  short  and  pointed, 
the  mandibles  (J  )  are  long  and  setiform,  but 
larger  than  the  maxilla  (g),  and  the  lingua  (*), 
according  to  Savigny's  observations,  forms  a 
short  trifid  process  within  the  cavity  of  the 
mouth,  at  the  base  of  the  maxilla,  the  covering 
or  sheath  to  the  parts  being  formed,  as  in  the 
other  species,  by  the  labium. 

In  Homoptera,  which  are  considered  by 
many  naturalists  as  constituting  only  a  division 
of  the  Hemiptera,  the  general  form  of  the  head 
is  that  of  a  triangle,  the  lateral  and  basilar 
angles  of  which  are  occupied  by  the  protu- 
berant cornea.  In  the  Cicadiida  the  epicra- 
nium  is  short  but  exceedingly  wide,  bearing  at 
its  sides  on  distinct  pedicles  the  large  project- 
ing cornea  similar  to  the  pedunculated  eyes  of 
Diopsis,  one  of  the  Diptera.  The  epicranial 
suture  is  most  distinctly  marked.  It  passes 
outwards  from  the  middle  line  on  each  side 
behind  a  large,  convex,  transversely  striated 
protuberance  on  the  front,  which  is  the  proper 
clypeus  posterior,  as  far  as  the  base  of  the 
pedunculated  corneae,  where  the  antenna  are 
inserted  immediately  in  front  of  it.  The  ocelli, 
three  in  number,  arranged  in  a  triangle,  are 
placed  on  the  most  vertical  part  of  the  epicra- 
nium,  and  the  suture  passes  through  the  ante- 
rior one.  The  clypeus  anterior  is  a  short 
triangular  plate,  united  by  suture  to  the  anterior 
margin  of  the  clypeus  posterior.  It  has  usually 
been  described  as  the  labrum.  The  proper 
lubrum  is  a  small  pointed  corneous  plate,  which 
covers  the  base  of  the  proboscis  in  front,  and 
is  freely  articulated  to  the  margin  of  the  clypeus. 
It  has  been  figured  by  Messrs.  Kirby  and 
Spence*  as  an  appendage  to  the  labrum  ( appen- 
dicula ),  which,  as  just  shown,  is  the  clypeus 
anterior.  It  is  often  partially  concealed  beneatli 
the  clypeus.  The  mandibles  and  maxilla  are 
usually  strong  corneous  seta,  contained  within 
the  sheath  formed  by  the  labium.  At  the  base 
of  the  maxilla,  concealed  by  the  labium,  are 
twoshort  membranaceous  appendages,  which  are 
probably  the  rudimentary  maxillary  palpi.  They 
are  attached  to  the  external  under  surface  of 
the  maxilla,  and  are  entirely  concealed  by 
the  labium.  In  the  Fulgorida,  as  in  Fulgora 
candelaria,  the  epicranial  region  constitutes  the 
greater  portion  of  the  head.  The  large  curved 
process  or  horn  on  the  front  is  derived  entirely 
from  the  epicranium.  The  cornea,  which  are 
remarkably  protuberant,  are  included  within 
the  same  region  at  the  sides  of  the  head,  as 
also  are  the  two  ocelli,  which  are  placed  one 
on  each  side  immediately  before  the  cornea. 
The  antenna  present  a  remarkable  character, 
being  formed  of  three  short  thick  joints,  ter- 
minated by  a  minute  setaceous  one.  The  third 
joint,  which  is  nearly  globular,  is  covered  with 
minute  protuberances,  somewhat  resembling 
the  structure  of  the  cornea,  or  rather  that  of 

"  Introduct.  vol.  iii.  pi.  6,  fig.  7,  a. 


the  antenna  in  the  males  of  Eucera  longicornis. 
These  organs  are  situated  in  deep  fossa,  into 
which  the  triangular  suture  enters.  The  clypeus 
posterior  forms  the  chief  portion  of  the  front, 
as  in  the  preceding  family,  the  clypeus  anterior 
a  narrow  plate  united  to  the  latter  by  suture, 
and  the  labrum  a  small  triangular  appendage. 

We  have  entered  thus  minutely  into  an 
examination  of  the  parts  of  the  head  and  mouth 
in  the  different  orders  of  insects,  in  consequence 
of  the  uncertainty  which  has  hitherto  existed 
among  naturalists  with  regard  to  the  number  of 
segments  of  which  the  head  is  normally  com- 
posed, and  also  because  it  was  necessary  that 
we  should  first  show  the  analogous  parts  of  the 
head  in  the  different  orders  before  stating  our 
opinions  with  regard  to  the  manner  in  which 
they  are  developed ;  and  further,  because  from 
the  minuteness  of  the  subjects  and  consequent 
difficulty  of  investigation,  the  most  ample 
elucidation  was  necessary  upon  which  to  base 
our  opinions. 

In  our  examination  of  the  remaining  parts 
of  the  skeleton  the  same  minuteness  will  be  of 
less  consequence,  because  the  parts  are  more 
easily  examined,  and  have  already  been  identi- 
fied through  the  excellent  and  elaborate  investi- 
gations of  Audouin,  Macleay,  and  others. 

Developement  of  the  head. — We  have  seen 
in  our  examination  of  the  perfect  insect,  that  the 
head  is  normally  composed  of  four,  and  appa- 
rently even  of  five  sub-segments,  as  is  proved 
by  the  existence  of  the  parts  we  have  de- 
scribed, which  correspond  to  the  superior  and 
inferior  arches  of  that  number.  The  fiust,  or 
most  anterior  of  these  sub-segments,  is  formed 
by  the  labrum  above  and  the  ligula  below  ;  the 
second,  by  the  clypeus  anterior  and  the  men- 
turn;  the  third,  by  the  clypeus  posterior  and 
submentum.  But  the  fourth,  which  has  be- 
come entirely  atrophied,  is  represented  above 
only  by  the  little  bones  of  the  antenna,  within 
the  cranium,  and  perhaps  also  the  cornea  ;  and 
below  by  that  reduplicature  of  tegument  which 
forms  in  some  insects,  as  in  Hydrous,  the  large 
transverse  bone,  or  ridge  between  the  submen- 
tum and  anterior  margin  of  the  gula;  while  the 
fifth  is  formed  by  the  epicranial  region  above, 
and  the  gula  and  broad  basilar  region  below, 
the  greater  size  of  this  sub-segment  being  the 
result  of  its  confluence  with  the  preceding  one, 
the  fourth,  which  has  disappeared.  The  num- 
ber and  position  of  these  parts  are  precisely 
similar  in  the  larva  and  the  perfect  insect,  as 
seen  in  Coleoptera,  Hymenoptera,  and  the  ver- 
miform larva  of  Uiptera.  In  each  of  these 
instances  the  greater  or  less  distinctness  of  the 
parts  is  in  an  inverse  ratio  to  the  more  or  less 
perfect  organization  of  the  individual.  Thus, 
if  we  take,  for  example,  the  head  of  the  larva  of 
the  common  Chaffer-beetle,  Melolonthu,  the 
first,  second,  third,  and  fifth  sub-segments  are 
very  distinct,  and  the  antenna,  inserted  at  the 
angles  of  a  strongly  marked  triangular  suture, 
indicate  the  situation  of  the  fourth  atrophied 
sub-segment.  But  in  the  perfect  beetle,  as  we 
have  formerly  seen,  not  only  have  all  these  se- 
parate parts  of  the  larva  become  confluent,  but 
their  previous  existence  as  distinct  pieces  is 


910 


INSECTA. 


scarcely  to  be  detected.  A  similar  condition  of 
parts  exists  in  the  heads  of  other  Coleoptera. 
The  disappearance  of  one  segment  of  the  head 
thus  early  in  the  larva  state  is  in  perfect  accord- 
ance with  that  progressive  developement  which 
we  know  takes  place  in  every  part  of  the  body, 
and  hence  it  was  to  be  expected,  that  those 
parts  in  which  the  changes  first  occur  are  those 
which  first  entirely  disappear.  Hence  the  dis- 
appearance of  the  fourth  subsegment,  which  we 
believe  exists  in  the  earliest  stages  of  the  larva, 
and  of  which  the  antennas  are  the  superior  ap- 
pendages. If  we  turn  from  this  transitory 
larva  state  of  the  insect  to  the  permanent  ver- 
miform condition  of  the  Annelida,  the  lower 
Articulata,  we  find  in  the  common  Nereis  a 
condition  of  the  head  apparently  analogous  to 
that  of  the  vermiform  larva.  It  is  elongated 
forwards,  and  formed  of  distinct  segments,  of 
which  the  posterior  ones,  as  in  insects,  support 
the  organs  of  vision.  But  these  remarks  on  the 
relations  of  the  different  parts  of  the  head  are 
offered  with  much  hesitation,  because,  in 
Myriapods,  which  have  usually  been  com- 
pared with  the  larvae  of  insects,  the  form  of  the 
head  seems  to  be  opposed  to  this  mode  of  view- 
ing its  development  in  Articulata,  since  the 
antennae  and  organs  of  vision  are  situated  on 
the  most  anterior  part  of  a  large  and  broad 
shield,  which  has  been  considered  the  first 
segment.  But  if  this  be  correct,  it  will  be  diffi- 
cult to  explain  the  circumstance  of  the  an- 
tennae and  corneae  of  hexapodous  insects  being 
constantly  situated  posteriorly  to  the  first  three 
sub-segments  of  the  head,  the  labrum  and  clypei. 

The  appendages  of  the  head,  which  form 
part  of  the  organs  of  manducation,  correspond 
in  number  to  the  number  of  sub-segments. 
These  parts  are  analogous  to  those  which  consti- 
tute the  organs  of  locomotion,  when  attached  to 
other  segments  of  the  body,  as  in  Myriapoda, 
and  Crustacea.  In  the  head  of  an  insect  the 
mandibles  are  the  proper  appendages  of  the 
fifth  or  basilar  sub-segment,  while  a  small  but 
freely  articulated  lobe,  which  sometimes  exists, 
as  in  some  of  the  Bruchehitra,  at  the  inner 
side  of  the  mandible,  appears  to  represent  that 
of  the  fourth.  The  stipes,  or  external  portion 
of  the  maxilla,  which  at  its  base  articulates 
with  the  cardo,  and  at  its  distal  extremity  is 
connected  with  the  palpus,  seems  to  be  the 
proper  appendage  of  the  submentum,  while 
the  inner  portion  of  the  maxilla,  which  origi- 
nally appears  to  be  a  distinct  part,  and  which 
at  its  distal  extremity  supports  the  galea, 
seems  to  be  the  proper  appendage  of  the  se- 
cond sub-segment,  and  the  labial  palpi  in  like 
manner  represent  those  of  the  ligula  or  first. 
It  has  been  shewn  by  Savigny  and  others,  that 
these  analogues  of  the  organs  of  locomotion 
undergo  a  very  gradual  change  of  form  and  use 
in  the  different  classes.  In  Myriapoda  the  ap- 
pendages that  belong  to  the  basilar  segment  of 
the  head,  which  constitute  the  mandibles,  are 
greatly  enlarged,  and  are  directed  forwards  as 
organs  of  prehension,  like  the  chelate  organs  of 
Crustacea  and  Arachnida,  but  are  jointed  and 
retain  the  exact  form  of  true  legs.  In  insects 
the  mandibles  are  in  like  manner  directed  for- 


wards, and  are  placed  above  those  of  the  pre- 
ceding segments,  but  are  compressed,  and  mate- 
rially altered  in  size  and  shape,  their  terminal 
portions,  the  tarsal  joints,  being  undeveloped, 
and  the  tibia  alone  enormously  enlarged,  con- 
stituting the  whole  jaw  or  manducatory  organ, 
while  the  basilar  joints,  the  femur  and  coxa, 
are  lost  in  the  under  surface  of  the  segment, 
with  which  they  have  become  confluent.  That 
this  is  really  the  case  is  proved  by  the  fact  that 
all  the  muscles  that  belong  to  these  powerful 
organs  are  attached  to  the  basilar  and  postero- 
lateral parts  of  the  head,  in  the  very  situations 
which  they  must  have  occupied  had  the  organs 
remained  free  for  the  purposes  of  locomotion 
or  prehension,  as  in  Crustacea,  Arachnida,  or 
Myriapoda.  That  this  confluence  of  parts  has 
in  reality  taken  place  is  further  proved  by  the 
circumstance,  that  the  outlines  of  the  portions 
that  become  united  with  the  skull  are  distinctly 
marked  in  Lucanus  cervus,  and  still  more 
clearly  in  that  of  the  great  Hydrous  (Jig.  369, 
o).  There  is  a  remarkable  illustration  of  the 
principle  upon  which  the  change  of  form  in 
the  adaptation  of  these  organs  to  a  new  func- 
tion depends,  in  that  curious  instance  of  mon- 
strosity in  an  individual  of  Geotrupes  sterco- 
rarius,  described  in  a  former  page  (860),  in 
which  the  tibiae  of  the  pro-thoracic  legs  l^e 
been  arrested  in  their  development,  and  are 
lunated  like  the  proper  mandibles,  the  tarsi 
being  entirely  absent.  In  a  remarkable  insect, 
Onitis  uygulus,  to  which  our  attention  was 
directed  by  Mr.  Shuckard,  there  is  a  further 
illustration  of  this  principle,  in  the  permanent 
condition  of  the  pro-thoracic  legs  of  that  spe- 
cies, in  which  the  tarsi  are  entirely  absent,  and 
the  tibiae  are  lunated  and  terminated  each  by  a 
sharp  hook.  There  is  also  a  similar  condition 
of  the  same  parts  in  other  species,  0.  Olivierii, 
0.  serripes,  and  O.chinensis  and  Apelles,  while 
in  a  species  of  a  neighbouring  genus,  Bubos  bison, 
the  tibiae  are  considerably  narrower  than  in  the 
preceding,  and  approach  much  nearer  in  shape 
to  the  instance  of  monstrosity  in  Geotrupes, 
thus  distinctly  indicating,  not  only  that  the 
form  of  parts  depends  either  upon  excessive  or 
deficient  developement,  but  also  that  the  abnor- 
mal conditions  occasionally  met  with  in  some 
species  are  permanent  normal  conditions  in 
others. 

From  the  manner  in  which  the  appendages 
of  the  cranial  sub-segments  are  arranged  to  form 
the  parts  of  the  mouth,  it  necessarily  follows 
that  the  most  posterior  pair,  the  mandibles, 
are  carried  upwards,  and  become  the  superior 
lateral  organs ;  while  the  maxillae  obtain  the 
next  place  beneath  them,  and  the  whole  are 
covered  in  by  the  inferior  arches  of  their  re- 
spective sub-segments,  which  constitute  the 
labium. 

In  all  insects,  the  whole  of  the  parts  of  the 
head  in  the  perfect  individual  exist  in  the  head 
of  the  larva,  the  changes  which  take  place 
being  only  those  of  size  and  relative  position. 
When  the  head  of  the  larva  is  smaller  than  that 
of  the  future  imago,  as  in  the  Hymenoptera, 
its  increase  of  size  just  before  the  insect  changes 
into  a  nymph,  and  when  a  great  portion  of  the 


INSECTA. 


911 


head  is  found  beneath  the  skin  of  the  second 
segment,  does  not  depend  upon  its  having  be- 
come confluent  or  united  with  a  portion  of  that 
segment,  but  upon  the  development  of  those 
parts  which  already  existed  in  it  in  the  larva,  so 
that  the  diminution  which  the  second  or  pro- 
thoracic  segment  undergoes  is  simply  an  atro- 
phied condition,  which  results  from  the  deve- 
lopment of  the  adjoining  parts,  and  not  from 
an  actual  union  or  coalescence  with  them  ; 
since  in  every  instance  in  which  apart  becomes 
confluent  with  an  adjoining  one,  it  loses  its  dis- 
tinctness of  form  and  character,  and  does  not 
remain  free  as  when  simply  atrophied,  or  ar- 
rested in  its  developement.  J3ut  when  the  head 
of  the  perfect  insect  is  smaller  than  that  of  the 
larva,  as  in  the  Lepidoptera,  the  extent  of  the 
pro-thoracic  segment  is  not  diminished,  unless 
encroached  upon  from  behind  by  the  enlarge- 
ment of  the  meso-thorax. 

The  thorax  is  that  region   of  the  body 
which  immediately  follows  the  head,  and  bears 
all  the  organs  of  locomotion  in  the  perfect 
insect.    It  is  always  composed  of  three  very 
distinct  segments,  first,  the  pro-thorax,  which 
bears  the  first  pair  of  legs ;  second,  the  meso- 
thorax,  which  bears  the  first  pair  of  wings  and 
second  pair  of  legs ;  and  third,  the  meta- 
thorax,  which  bears  the  second  pair  of  wings 
and  third  pair  of  legs.    Besides  these  seg- 
ments, which  are  analogous  to  the  second, 
third,  and  fourth  in  the  larva  state,  there  is  also 
another,  the  fifth  segment  of  the  larva,  which 
enters  in  part  into  the  composition  of  the  thorax 
of  the  perfect  insect,  and  forms  its  connexion 
with  the  abdominal  region.    We  have  already 
alluded  to  this  in  our  account  of  the  changes  of 
the  larva,  (p.  877,  8,)  during  which  we  have 
shewn  that  at  least  one  segment  of  the  body 
always  becomes  atrophied,  and  very  frequently 
almost  disappears,  and  that  this  segment  is  the 
fifth.    But  we  have  not  there  sufficiently  ex- 
plained that  this  segment  belongs  partly  to  the 
thoracic  and  to  the  abdominal  regions,  on  which 
account  we  propose  to  designate  it  the  tho- 
racico-abdominal  segment,  and  consequently  the 
number  of  segments  of  which  the  abdomen  is 
composed  will  depend  upon  whether  or  not  we 
include  this  in  that  region.    For  our  own  parts 
we  prefer  to  consider  it  as  forming  a  most  dis- 
tinct part,  for  reasons  which  we  shall  presently 
explain.    Now  it  has  been  shewn  by  M.  Au- 
douin,  in  an  admirable  and  elaborate  series  of 
investigations,  that  each  segment  of  the  thorax 
is  normally  composed  of  four  sub-segments, 
which  sub-segments  or  annuli  are  each  formed 
of  distinct  parts,  one  upper  or  dorsal,  one  lower 
or  pectoral,  and  two  lateral.    The  four  annuli 
thus  formed  are  easily  demonstrable  on  the 
upper  surface  of  each  thoracic  segment,  but  are 
less  readily  detected  on  the  pectoral  or  under 
surface,  in  consequence  of  the  parts  having 
there  become  confluent,  in  order  to  afford  a 
greater  degree  of  solidity  to  the  skeleton  ;  and 
in  consequence  also  of  the  diminished  extent  of 
the  pectoral  as  compared  with  the  dorsal  sur- 
face, which,  as  before  explained,  (page  877,)  is 
dependent  upon  the  greater  extent  of  change 
that  takes  place  on  the  pectoral  than  on  the 


dorsal  surface  during  the  metamorphoses  of  the 
insect.    The  parts  capable  of  demonstration  in 
each  segment,  according  to  the  views  of  Au- 
douin,  are,  on  the  upper  or  dorsal  surface,  the 
prctscutum,  scutum,  scutellum,  and  post-scutel- 
lum  ;  on  the  inferior  or  pectoral  surface  a  single 
piece,  the  sternum,  and  on  the  lateral  two 
pieces,  the  episiernum  and  epimeron  on  each 
side ;  in  addition  to  which  there  are  also  two 
evanescent  pieces,  which  are  of  considerable 
size  in  some  species,  but  scarcely  distinguish- 
able in  others.    These  are  the  paraptera,  por- 
tions of  the  thorax  not  articulating  with  the 
sternum,  but  with  the  episiernum,  anterior  to 
each  wing,  and  the  trochantin,  articulating  with 
the  epimeron  and  coxa  of  the  leg,  the  parap- 
tera of  the  pro-thorax  being,  according  to 
Audouin,  absent.     Hence    the  number  of 
pieces  he  describes  as  forming  the  external 
thorax  are  ten  for  the  pro-thorax,  twelve  for  the 
meso-thorax,  and  a  like  number  for  the  meta- 
thorax,  making  in  all  thirty-four  pieces.  These 
are  parts  capable  of  being  demonstrated,  if  we 
regard  each  sternum  as  formed  of  two  trans- 
verse pieces  united,  and  corresponding  to  the 
episterna  and  epimera.    But  as  remarked  by 
Mr.  Macleay,*  each  sternum  at  the  maximum 
of  development  ought  to  be  regarded,  like  the 
dorsal  surface  of  each  segment,  as  composed 
of  four  transverse  sub-segments  united  longitu- 
dinally, and  the  sides  of  the  same  number.  If 
then  the  lour  portions  on  the  dorsal  surface  of 
each  segment,  and  the  sternum  on  the  under, 
be  also  divided  in  the  median  line,  the  number 
of  pieces  in  the  thorax  will  amount  to  seventy- 
two.    But  this  number,  as  Mr.  Macleay  has 
well  remarked,  can  never  appear  together  in 
any  insect,  owing  to  the  great  extent  to  which 
some  parts  are  developed,  and  the  consequent 
atrophy  of  others.    At  the  same  time  it  must 
be  observed,  that  if  we  adopt  this,  which  ap- 
pears to  be  the  correct  theoretical  mode  of  con- 
sidering the  subject,  the  number  of  pieces 
which  enter  into  the  composition  of  the  thorax 
is  in  reality  greater  than  that  given  by  M. 
Audouin,  who  has  not  described  any  parts  be- 
longing to  the  pro-thorax  as  analogues  of  the 
paraptera  of  the  meso-  and  meta-thorax,  but 
which  we  think  may  be  found  in  a  pair  of  those 
little  detached  plates  that  exist  in  the  articu- 
lating membrane  between  the  head  and  pro- 
thorax  in  Coleoptera,  and  which  have  been 
described   by   Straus  Durckheimf   as  pieces 
jugulaires,  and  conceived  by  him  to  represent 
the  remains  of  two  distinct  segments,  situated 
originally  between  the  head  and  pro-thorax,  but 
which  have  disappeared  during  the  transforma- 
tions.   But  we  are  more  inclined  to  consider 
them  as  detached  portions  of  the  pro-thorax 
than  as  remains  of  distinct  segments,  since  we 
are  totally  unaware  that  any  such  disappear- 
ance of  segments  ever  takes  place  between  the 
head  and  pro-thorax ;  the  head  or  first  segment 
of  every  Coleopterous  larva  being  the  proper 
representative  of  the  head  of  the  perfect  insect ; 
and  the  second  segment  of  the  larva  being  in 

*  Zoological  Journ.  vol.  i.  p.  177. 
f  Considerations  Gen.  &c.  p.  75. 


912 


INSECTA. 


like  manner  that  of  the  pro-thorax,  the  change 
which  takes  place  between  these  two  segments 
during  the   metamorphoses  being  chiefly  a 
shortening  of  the  sternal  surface  of  the  pro- 
thorax,  or  second  segment,  occasioned  by  a  re- 
flexion inwards  of  a  portion  of  the  external 
tegument,  to  form  the  articulation  as  in  other 
insects.    If,  therefore,  we  include  the  jugular 
pieces  of  Straus  as  the  analogues  of  the  parap- 
tera,  the  external  surface  of  each  of  the  three 
thoracic  segments  will  be  found  to  consist  of 
twelve    primary    and    readily  demonstrable 
pieces,  making  in  all  thirty-six,  the  number 
which  we  believe  always  enters  into  the  compo- 
sition of  the  thorax,  as  formerly  stated  by  M. 
Jurine.    But  it  is  probable  that  the  parts  de- 
scribed by  M.  Audouin,  and  recognised  by  our- 
selves, are  not  identical  with  those  of  that 
author,  since  the  scutum  of  the  meso-thorax  in 
Hymenoptera,  as  will  presently  be  seen,  and  as 
formerly  pointed  out  by  Mr.  Macleay,*  is  not 
only  divided  in  the  median  line,  but  its  two 
sides  are  also  separated  by  a  deep  longitudinal 
fissure  each  into  two  parts,  the  outermost  of 
which   Mr.  Macleay    designates  parapsides. 
This  division  of  the  scutum  of  the  meso-tho- 
rax, if  constant  in  the  other  orders,  would  raise 
the  number  of  distinct  pieces  to  thirty-eight. 
M.  Audouin,  who  adopts  the  name  given  to 
these  parts  by  Mr.  Macleay,  states  that  although 
he  was  previously  well  acquainted  with  this 
division  of  the  scutum  in  Hymenoptera,  he 
did  not  assign  names  to  the  pieces  because  he 
considered  them  rather  as  mere  divisions  of  the 
scutum  itself  than  as  distinct  parts  of  the  ske- 
leton.  The  existence  of  these  pieces,  therefore, 
in  Hymenoptera,  is  a  circumstance  connected 
with  the  number  and  identification  of  the  nor- 
mal parts  of  the  skeleton,  which,  it  must  be 
acknowledged,  offers  not  a  little  difficulty,  be- 
cause if  it  be  ultimately  found  that  these,  which 
are  so  distinct  in  some  genera,  the  Chryudida:,  be 
in  reality  normal  parts  of  the  mesothorax  which 
are  thus  shown  to  exist  as  such  only  by  this 
segment  being  developed  to  its  maximum  ex- 
tent in  this  Order,  it  must  be  admitted  that 
they  also  exist  primarily  in  all  other  insects, 
not  merely  in  the  mesothorax,  but  in  the  pro- 
and  metathorax,   so  that  the  dorsal  surface 
of  each  thoracic  segment  must  be  regarded  as 
formed  not  of  four  but  of  sixteen  parts,  the 
praescutum,    scutellum,    and  post-scutellum 
being  each  divided  in  the  same  manner  as  the 
scutum  into  four  pieces,  first  by  a  median  line 
into  two  halves,  and  these  again  divided  late- 
rally into  two  others.    The  two  middle  pieces 
would  then  constitute  the  no  turn,  or  dorsal  sur- 
face of  each  segment,  and  the  two  lateral  the 
parapsides.    An  equal  number  of  parts  must 
then  be  recognised  as  entering  into  the  forma- 
tion of  the  ventral  arch  of  each  segment.  Each 
middle  or  sternal  piece,  formed  of  four  con- 
secutive pieces,  analogous  to  those  of  the  dorsal 

*  Zoological  Journ.  vol.  i. 


arch,  and  divided  in  the  median  line,  would 
correspond  to  the  middle  series  of  dorsal  pieces, 
the  proper  notum,  and  a  like  number  on  each 
side  of  the  sternum  would  correspond  to  the 
lateral  portions  of  the  dorsal  arch,  the  parap- 
sides.   Of  these  lateral  pieces  of  the  ventral 
arch,  three  are  already  known  in  each  segment, 
as  we  shall  presently  find,  the  parapterun,  epi- 
sternum,  and  epimeron.    But  since  there  has 
never  yet  been  actually  found  even  an  approxi- 
mation to  this  multitude  of  pieces  in  the  dorsal 
surface  or  arch  of  the  thorax,  we  prefer  for 
the  present  to  follow  the  views  of  M.  Audouin, 
and  with  him  to  regard  the  parapsides  as  only 
detached  portions  of  the  scutum  in  Hymenop- 
tera, in  which  the  development  of  the  meso- 
thorax is  carried  to  its  greatest  extent.   It  must 
be  acknowledged,  however,  that  in  admitting 
the  parapsides  to  be  only  detached  portions  of 
the  scutum,  and  not  primary  parts,  the  same 
thins  may  be  urged  with  regard  to  some  of 
those  which,  according  to  M.  Audouin's  views, 
are  believed  to  be  normal  structures.    But  this 
objection  seems  to  be  replied  to  by  the  fact 
that  the  pieces  described  by  M.  Audouin  are 
almost  always  found  to  exist  most  distinctly 
marked,  whether  developed  to  a  greater  or  less 
extent,  in  the  generality  of  insects.  Thirty- 
six,  therefore,  we  regard  as  the  number  of 
the  distinct  external  parts  of  the  thorax.  Yet 
even  this  is  more  than  has  been  recognized 
by  others  who  have  attended  to  this  subject. 
Thus  Knoch  describes  only  twelve,  Chabrier 
and  Burmeister,  eighteen  ;  Kirby  and  Spence, 
twenty ;  Straus  Durckheim,  twenty-two  ;  and 
Macleay,  fifty-four.  But  whatever  be  considered 
the  exact  number,  they  are  never  all  distinctly 
developed  in  every  insect,  owing  to  the  causes 
before  explained  with  reference  to  the  greater 
developement  of  some  parts  than  of  others,  al- 
though some  trace  of  the  existence  of  the  atro- 
phied pieces  usually  remains.  It  is  owing,  also, 
to  the  same  causes,  that  the  actual  position  of 
the  parts  becomes  altered  in  different  insects, 
although  their  relative  position  continues  the 
same. 

Very  much  confusion  has  arisen  in  the  de- 
scriptions of  the  parts  of  the  thorax,  in  conse- 
quence of  various  authors  applying  different 
names  to  the  same  parts  in  different  insects, 
and  also  from  the  uncertainty  which,  as  above 
shewn,  exists  in  the  opinions  of  authors  with 
regard  to  the  exact  number  of  pieces  that  enter 
into  the  composition  of  the  thorax.  In  order, 
therefore,  to  obviate  as  much  as  possible  this 
serious  inconvenience  and  difficulty  in  recog- 
nizing the  parts,  we  shall  add  a  table  of  the 
names  given  to  them  by  Audouin,  with  refe- 
rences to  the  delineations  of  them  by  that 
author,  and  also  the  synonyms  used  by  other 
writers.  In  doing  this  we  shall  also  adopt 
Burmeister's  very  convenient  names  for  the 
upper  and  under  surface  of  each  thoracic  seg- 
ment, which  are  equally  simple,  and  distinctive 
of  the  parts  to  which  they  are  applied. 


INSECTA. 


VOL.  tt. 


3  o 


914 


INSECTA. 


The  pro-thorax,  as  we  have  stated,  is  com- 
posed of  four  sub-segments,  which  on  its  upper 
surface,  or  pro-notum,  are  generally  confluent, 
more  particularly  in  Coleoptera,  and  form  a 
smooth,  uniform,  and  often  very  broad  surface. 
In  shape,  the  pro-notum  is  usually  more  or  less 
quadrate  and  convex,  with  its  sides  arched  and 
dilated.  In  many  species,  as  in  some  families 
of  Coleoptera,  Orthoptera,  and  Homoptera, 
the  pro-notum  is  larger  than  the  corresponding 
part  of  any  segment  of  the  body,  being  consi- 
derably broader  and  longer  than  the  head. 
This  is  the  case  more  especially  in  those  in- 
sects which  are  much  employed  in  burrowing, 
as  in  Gfyllotalpa,  Geotrupida,  Copridte,  and 
Silphida.  Sometimes,  as  in  the  Cercopkte,  it 
is  enormously  enlarged.  In  Membracisjolidta 
it  is  developed  in  the  median  line  into  an  ele- 
vated crest  like  that  of  a  helmet,  which  is  not 
only  extended  forwards  so  as  completely  to 
conceal  the  head,  but  also  laterally  and  back- 
wards over  the  whole  body.  In  others  of  the 
same  family,  as  in  Ledra,  it  resembles  an  acute 
triangle,  its  sides  being  developed  into  two  ob- 
tuse processes,  while  it  is  elongated  backwards 
like  an  acute  spine,  which  completely  covers 
the  abdomen.  In  other  instances,  as  in  Dynas- 
tidce,  (Jig.  333,)  it  is  developed  into  a  strong 
horn  or  process,  which  is  as  long  as  the  whole 
body.  In  each  of  these  instances,  the  abnormal 
form  and  size  depend  either  upon  the  exces- 
sive development  of  the  whole  of  the  sub- 
segments,  as  in  Gryllotalpa,  or  upon  one  or 
more  of  them,  as  in  Dynustes,  since  in  those 
species  in  which  the  parts  of  the  pro-notum  are 
all  nearly  equally  developed,  and  are  of  moderate 
size,  their  lines  of  separation  are  very  distinctly 
marked,  as  in  the  common  green  grasshopper, 
Acrida  viridissima.  The  pro-sternum,  or  under 
.surface  of  the  pro-thorax,  is  considerably  shorter 
than  the  pro-notum.  In  Dyticus  circumflexus 
(fig.  384  A),  the  species  selected  by  Audouin 


Fig.  384. 


A,  under-surface  of  the  first  segment  of  the 
thorax  or  pro-sternum  of  Dyticus  circumflexus, 
(Audouin);  2  g,  pro-sternum;  2  f,  episternum  ; 
2  h,  epimeron  ;  2  s,  ante-furca  or  ento-thorax. 

for  the  purpose  of  illustrating  the  anatomy  of 
the  thorax  in  Coleoptera,  it  is  divided  into 
three  distinct  pieces.  The  sternum,  or  largest 
piece,  (2  g,)  is  situated  in  the  middle  line,  and 
is  of  a  triangular  form.  It  is  extended  on 
each  side,  at  the  anterior  part  of  the  segment, 
into  two  processes,  which  articulate  at  their  ex- 
tremities by  a  distinct  suture  with  the  produced 
margins  of  the  pro-notum.  Posteriorly  to  these 
it  is  developed  in  the  median  line  into  a  spine 
or  crest,  on  each  side  of  which  it  is  hollowed 
out  to  form  part  of  the  acetubula,  into  which  the 
coxae  of  the  anterior  legs  are  inserted.  External 


to  each  acetabulum  is  a  broad  and  somewhat 
triangular-shaped  plate,  the  episternum  (2 /). 
This  part  is  united  by  suture  at  its  anterior 
margin  to  the  extended  part  of  the  sternum,  by 
its  superior  border  to  the  dilated  margin  of  the 
pro-notum,  and  by  its  posterior  to  the  epimeron. 
It  is  a  very  distinct  piece,  and  does  not  enter  at 
all  into  ihe  formation  of  the  acetabulum,  as  it 
appears  to  do  on  a  cursory  examination.  The 
third  piece,  the  epimeron  (2  h),  is  that  which  is 
always  connected  with  the  coxa,  or  basial  joint 
of  the  leg.  In  this  species  it  is  a  narrow  plate, 
situated  posteriorly  to  the  episternum,  and 
forms  the  posterior  margin  of  the  sternal  surface 
of  the  pro-thorax.  At  its  sternal  end  it  has  a 
short  process,  that  forms  the  outer  margin  of 
the  acetabulum,  and  articulates  both  with  the 
sternum  and  episternum.  It  is  probable  that  a 
portion  of  this  process  is  the  proper  trochantin 
of  the  leg  on  each  side,  since  the  part,  which 
has  been  described  by  Audouin  as  the  tro- 
chantin in  the  meso-  and  meta-thoracic  seg- 
ments, has  not  been  delineated  in  his  drawing 
of  the  pro-thoracic.  In  Dyticus  marginatis 
there  is  a  mark  upon  the  process  which  resem- 
bles a  suture,  and  which  still  further  induces  us 
to  believe  that  this  part  is  the  analogue  of  the 
trochantin.  Within  the  cavity  of  the  pre- 
thorax,  extending  upwards  from  their  attach- 
ment to  the  pro-sternum,  are  two  bony  rami, 
which  at  their  inferior  extremity  are  developed 
into  two  rounded  plates  (2  s ),  that  form  a  col- 
lar, or  leave  a  circular  hole  between  them  for  the 
passage  of  the  spinal  cord.  They  constitute 
the  ante:furca,  the  ento-thorax  of  Audouin. 
These  are  the  parts  that  enter  into  the  formation 
of  the  pro-thorax,  exclusive  of  the  anterior  pair 
of  legs,  the  only  appendages  of  this  segment. 


Fig.  385. 


Part  of  the  meso-thorax.    (  Audouin.) 
A,  meso-sternum ;  3  a,  praescutum  ;  3  b,  scutum  ; 
3  c,  scutellum;  3  d,  post-scutellum  ;  3  e,  parapte- 
ron;  3  g,  meso-sternum  ;  3/,  episternum  ;  3  h,  epi- 
meron ;  3  s,  medifurca,  or  ento-thorax. 

The  meso-thorax,  (jig.  385,)  or  third  segment 
of  the  body,  is  usuaily  less  developed  in  this 
order  than  the  pro-thorax,  with  which  it  is  freely 
articulated  by  a  strong  membrane.  It  is,  as  its 
name  implies,  the  middle  portion  of  the  tho- 
rax, and  in  most  instances  its  division  into  four 
sub-segments  is  distinctly  marked  on  its  dorsal 


INSECTA. 


915 


Surface,  or  meso-noturn.  It  is  the  segment 
that  bears  the  elytra  and  middle  pair  of  legs. 
The  first  piece,  the  prascutum  (3  a),  is  in  ge- 
neral narrow  and  transverse  ;  it  is  very  readily 
overlooked,  being  in  most  cases  bent  down- 
wards to  form  the  meso-phrqgma,  the  anterior 
boundary  of  the  segment.  The  second  piece, 
the  scutum  (3  />),  is  a  much  broader  and  very 
distinct  corneous  plate,  and  may  be  regarded, 
perhaps,  as  the  most  important  division  ot  the 
meso-notum,  since  it  is  to  this  that  the  ante- 
rior pair  of  wings,  the  elytra,  are  articulated. 
It  is  followed  by  the  scutellum  (3  c),  which 
also  is  a  very  important  division.  Like  the 
scutum  it  is  a  broad  piece,  that  covers  the  pos- 
terior part  of  tire  meso-notum,  and  extends 
on  each  side  to  the  base  of  the  elytra,  the 
ulula,  which  arc  continuous  with  them,  being 
•attached  to  its  margin.  It  is  developed  in  the 
middle  line  into  a  remarkable  elevated  plate, 
that  is  shaped  like  an  armorial  shield,  and 
•is  so  exceedingly  large  in  some  species,  that 
it  covers  nearly  the  whole  of  the  body.  In 
Dyticus,  and  most  of  the  Coleoptera,  it  is  the 
small  triangular  plate  which  is  situated  be- 
tween the  elytra,  at  their  base,  and  is  supposed 
to  be  of  use  in  keeping  these  organs  steady 
during  flight.  The  fourth  and  last  piece  of  the 
meso-notum,  the  post-Hcutelktm  (3  d),  like  the 
prse-scutum,  is  narrow  and  inconspicuous.  It 
is  situated  immediately  behind  the  scutellum, 
and  is  the  posterior  boundary  of  the  meso- 
notum.  These  parts  together  form  the  dorsal 
surface  of  the  first  wing-bearing  segment, 
which  is  developed  to  as  great  an  extent  on  its 
tinder  as  on  its  upper  surface.  The  meso- 
notum  is  most  fully  developed  in  those  insects 
in  which  the  anterior  pair  of  wings  are  the 
largest,  as  in  the  Lepidoptera,  Ilymenoptera, 
and  Dipteia,  while  in  those  in  which  the  chief 
organs  of  flight  are  the  posterior  wings,  as  in 
the  Coleoptera,  it  is  the  smallest  of  the  three 
thoracic  segments.  The  mew-sternum  (fig.  385, 
A),  like  the  pro-sternum,  is  formed  by  a  strong 
middle  piece,  the  proper  sternum  of  the  seg- 
ment, (3  g,)  which  is  developed  laterally  into 
two  processes,  behind  which  the  coxae  of  the 
middle  pair  of  legs  are  articulated,  and  anteri- 
orly and  laterally  the  episterna  (3  /')  and  epi- 
mera  (3  h).  Each  episternal  piece  is  a  broad 
elongated  plate,  which  forms  the  anterior  part  of 
the  meso-sternum.  It  is  attached  to  the  ante- 
rior margin  of  the  lateral  sternal  process,  so 
that  its  actual  position  is  a  little  altered,  the 
corresponding  part  of  the  pro-thoracic  segment 
being  situated  behind  the  process  of  the  sternal 
piece.  This  is  a  circumstance  which  occa- 
sionally takes  place  in  the  development  of 
every  part  of  the  skeleton,  the  actual  position  of 
one  part  being  altered  by  the  greater  or  less  de- 
velopement  of  another,  while  the  relative  posi- 
tion of  each  part  always  continues  the  same. 
Thus,  although  the  episternum  is  situated  more 
anteriorly  in  the  meso-  than  in  the  pro-sternal 
surface,  it  still  continues  to  be  articulated  with 
the  sternum.  The  epimeron  (3  A)  is  situated 
behind  the  episternum.  It  is  a  narrow  elon- 
gated plate,  that  forms  the  posterior  portion 
of  die  meso-thorax,  and  is  united  to  the  anterior 


of  the  meta-thorax.  At  its  superior  extremity 
it  is  much  broader  than  at  its  inferior,  which  is 
articulated  with  the  extremity  of  the  sternal 
process,  and  also  with  the  coxae  of  the  middle 
legs.  At  the  anterior  border  of  the  episternum 
there  is  a  verv  narrow  but  distinct  plate,  the 
parapteron  (3  e).  This  piece,  which  is  con- 
nected especially  with  the  wings,  undergoes  a 
great  change  of  form  and  size  in  the  different 
orders.  In  the  Coleoptera.  it  is  narrow  and 
evanescent,  but  as  we  shall  hereafter  see,  is 
largely  developed  in  the  Lepidoptera.  It  is 
evidently  a  normal  portion  of  the  skeleton,  but 
has  only  been  described  by  Audouin  as  found 
in  the  meso-  and  meta-thoracic  segments.  We 
have  before  alluded  to  the  existence  of  two 
detached  pieces  in  the  connecting  membrane  of 
the  pro-thorax  and  head,  which  we  regard  as 
the  analogues  of  these  pieces  of  the  meso-  and 
meta-thorax.  If  this  be  correct,  the  relative 
position  of  these  to  the  other  parts  of  the  pro- 
sternum  is  precisely  similar  to  that  of  the  same 
parts  of  the  meso-stemum.  The  medifurca, 
(3  s,)  or  ento-thorax  of  this  segment,  is  at- 
tached to  the  internal  surface  of  the  sternal 
piece,  as  in  the  pro-thorax.  It  is  formed  by 
two  ascending  rami,  which  are  larger  and 
longer  than  those  of  the  pro-thorax,  but  like 
them  are  developed  into  two  expanded  por- 
tions, which  are  approximated  together  and 
form  an  arch,  under  which  the  nervous  cord 
passes  in  its  course  to  the  meta-thorax. 

Fig.  386. 
A  ^  4-a 


Parts  of  the  meta-thorax.    (  Audouin.) 
A,  meso-sternum  ;  4  a,  prae -scutum  ;  4  b,  scutum  ; 
4  c,  scutellum ;  4  d,  post-scutellum  ;  4  e,  parapteron ; 
4f,  episternum  ;  4  g,  meta-sternum -,  4  h,  epimeron  ; 
4  3,  post-furca. 

The  meta-thorax  (fig.  386)  is  the  fourth  seg- 
ment of  the  body,  and  the  third  of  the  thoracic 
region.  Its  upper  surface,  or  meta-notum,  as 
in  the  preceding  segments,  is  divided  into  four 
portions.  The  pra-scutum  (4  a)  is  a  narrow 
transverse  plate,  which  is  bent  down  at  its  ante- 
rior margin  like  the  prasscutum  of  the  meso- 
notum,  to  form  the  meta-phragma,  and  is  ex- 
tended on  each  side  as  far  as  the  paraptera, 
bounding  the  insertion  of  the  wings.  In  the 
middle  line  it  is  extended  backwards  upon  the 
dorsal  surface  as  far  as  the  scutellum,  thus  di- 
viding into  two  parts  the  second  piece,  the 
scutum,  (4  b,)  which,  like  the  corresponding 
part  of  the  meso-notum,  is  connected  with  the 

3  o  2 


916 


INSECTA. 


wings  of  the  segment.    This  connexion  is  the 
great  characteristic  of  the  scutum  in  all  insects. 
The  next  piece,  the  scutellum,  (4  c,)  is  a  much 
broader  plate,  and  is  extended  across  the  whole 
surface  of  the  meta-notum.    Like  the  corre- 
sponding piece  of  the  meso-notum,  it  bears  on 
the  middle  line  an  excavated  shield-shaped 
plate,  and  is  connected  at  its  external  margin 
with  the  borders  of  the  wings.    The  last  piece, 
the  post-scutellum,  ( 4  d,)  which,  although  nar- 
row like  the  prsescutum,  is  a  strong  horny  plate 
that  extends  on  each  side,  and  like  the  scutel- 
lum, is  connected  with  the  wings.  Its  posterior 
margin  is  bent  down  to  assist  in  forming  the 
division  between  the  thorax  and  abdomen,  and 
is  connected  with  the  remains  of  the  atrophied 
fifth  segment.    The  meta-stemum  (A)  is  fre- 
quently  the  most  developed  portion  of  the 
meta-thorax,    particularly    in    those  insects 
which,  as  Audouin  has  observed,  are  especially 
walkers.    In  Dyticus,  the  middle  piece,  the 
proper  sternum  (4  g),  is  a  smooth  expanded 
plate,  which  is  produced  at  its  anterior  part  into 
a  spine,  that  articulates  with  the  emarginated 
extremity  of  the  crest  of  the  meso-stemum.  On 
each  side  of  the  spine  it  is  developed  into  a 
broad,  smooth,  triangular  plate,  to  the  anterior 
border  of  which  is  articulated  the  episternum, 
(4  /',)  also  of  a  triangular  form.    This  piece  oc- 
cupies the  anterior  lateral  region  of  the  meta- 
sternum,  and  the  parapteron,  (4  e,)  which  is 
situated  immediately  beneath  the  insertion  of 
the  wing,  is  articulated  with  its  superior  border. 
The  epimeron  (4  It)  of  this  segment  is  exceed- 
ingly small,  and  appears  at  first  to  be  removed 
from  its  proper  situation,  being  carried  upwards 
to  the  side  of  the  body  by  the  enormously  ex- 
panded coxa  (/).    But  although  removed  from 
its  usual  situation,  and  reduced  in  size,  it  still 
retains  its  characteristic  distinction,  that  of  arti- 
culating with  the  coxa,  and  also  with  the  tro- 
chuntin  (?),  (/c,)  which,  although  minute,  is  in 
connexion  both  with  the  coxa  and  epimeron. 
The  mcta-j'urca,  or  ento-thorax  of  this  segment, 
(4  s,)  is  an  exceedingly  large  and  important 
piece,  shaped  like  the  letter  Y.    It  is  attached 
at  its  posterior  extremity  to  a  thin  vertical 
plate,  which  is  situated  between  the  united  coxte 
of  the  legs  of  this  segment,  and  it  is  also  arti- 
culated with  the  posterior  part  of  the  internal 
surface  of  the  meta-sternum.    From  this  at- 
tachment it  is  extended  upwards  and  forwards 
into  the  middle  of  the  meta-thorax,  where  it  is 
expanded  on  each  side  into  two  broad  curved 
plates,  to  which  the  muscles  of  the  posterior 
legs  are  attached.    In  the  middle  line  it  is 
grooved,  and  at  its' anterior  part  forms  a  par- 
tially covered  canal,  along  which  the  nervous 
cord  is  transmitted  in  its  course  to  the  abdo- 
men.   Besides  the  parts  now  described,  there 
are  also  two  curved  plates  reflected  inwards 
from  the  posterior  margin  of  the  meta-sternum, 
where  it  is  articulated  with  the  coxae,  and  also 
one  central  vertical  one,  which  arises  in  the  me- 
dian line  from  the  interior  surface  of  the  ster- 
num, and  which  appears  to  be  the  proper  inte- 
rior sternal  ridge.    Each  of  the  posterior  coxa; 
is  also  furnished  with  a  broad  plate,  which  is 
situated  within  the  meta-thorax,  on  each  side  of 


attachment  of  the  post-furca.  These  parts 
rd  attachments  for  the  muscles  of  the  legs. 

Fig.  337. 


Skeleton  of  Hydrous  piceus. 

A,  pectoral  surface  ;  B,  dorsal  surface  •,  2,  pro- 
nation ;  2  a,  prosternum  ;  2  /,  episternum  ;  meso- 


INSECTA. 


9-17 


notum ;  3  a,  prsescntum  ;  3  6,  scutum;  3  c,  scutcl- 
luin;  3  d,  post-scutcllum  •,  meso-sternum;  3  g,  ster- 
num ;  3  /(,  episternum  ;  of,  epimeron  ;  3  i,  crest  of 
the  meso-sternum  ;  3  e,  parapteron  ;  3  It,  trochan- 
tin  ;  4,  meta notum  ;  4  a,  praescutum  ;  4  i,  scu- 
tum ;  4  c,  scutellum  ;  4  d,  post-scutellum  ;  4  e, 
parapteron;  meta-sternum ;  4  f,  episternum;  4  g, 
meta-sternum  ;  4  h,  epimeron  ;  4  i,  crest  of  meta- 
sternum  ;  4  It,  trochantin  (?)  ;  4  I,  coxa  ;  4m,  tro- 
chanter ;  4  n,  femur ;  o,  tibia ;  p,  tarsus  ;  q,  un- 
guis. 

These  segments  constitute  the  proper  thorax 
of  the  insect,  and  the  parts  we  have  described 
are  found  in  nearly  all  the  Coleoptera,  the  most 
perfect  species  ;  although,  as  before  stated,  they 
are  sometimes  greatly  modified  in  shape,  and 
varied  in  size  and  position,  in  order  that  the 
body  of  the  insect  may  be  adapted  to  its  pecu- 
liar hubiis.    Thus  in  the  great  water-beetle, 
Hydrous  pictus,  (Jig.  337,)  which  in  its  general 
appearance  and  mode  of  life  very  nearly  resem- 
bles the  Di/ticus,  and  not  only  burrows  deeper 
into  the  mud  at  the  bottom  of  stagnant  waters, 
but  is  also  accustomed  to   float  among  the 
weeds  on  the  surface  to  bask  in  the  sun,  the 
form  of  the  sternum  is  admirably  adapted  to 
its  habits.    The  sterna  of  the  meso-thorax  and 
meta-thorax  are  not  only  both  armed  with  a 
strong  keel  like  a  boat,  but  the  two  are  firmly 
articulated  together,  which  enables  the  insect 
more  securely  to  float  on  the  surface  of  the 
water,  and  thus  afford  additional  strength  to  its 
whole  body  for  the  accomplishment  of  its  ob- 
ject.   But  in  the  Dt/ticus,  to  which  it  is  of 
the  utmost  consequence  to  be  able  to  swim 
with  the  greatest  rapidity,  and  turn  with  facility 
in  the  water,  in  the  pursuit  of  its  living  prey, 
the  pro-sternum  and  meso-sternum  only  are 
slightly  keeled,  while  the  meta-sternum  is 
smooth,  and  the  sides  of  the  body  are  acute, 
and  offer  the  least  possible  resistance  to  its 
movements.    In  addition  to  this,  to  afford  suf- 
ficient strength  to  the  body,  together  with  faci- 
lity of  motion,  the  sternum  of  the  meta-thorax 
is  produced  in  front  into  a  short  spine,  which  is 
inserted  into  a  notch  in  the  posterior  part  of 
the  meso-sternum  ;  while  the  coxse  of  the  poste- 
rior pair  of  legs  upon  which  the  chief  efforts  in 
swimming  depend,  although  enormously  en- 
larged to  afford  sufficient  space  for  the  inser- 
tion of  the  muscles,  are  flat  and  smooth  like  the 
rest  of  the  under  surface  of  the  body,  in  order 
that  they  may  not  oppose  the  slightest  impedi- 
ment to  the  motions  of  the  insect.  The  different 
forms  of  the  coxse  (/)  and  of  the  acetabula(4  /c), 
into  which  they  are  inserted,  have  also  a  refe- 
rence to  the  habits  of  the  species.    The  large 
posterior  coxa?  of  the  Vj/ticus  are  immoveably 
united  by  suture  to  the  posterior  margin  of  the 
meta-sternum,  because,  in  this  insect,  the  pos- 
terior pair  of  legs  being  especially  designed  for 
swimming,   and  their  motions  consequently 
being  almost  wholly  in  one  direction,  addi- 
tional strength  is  afforded  to  these  organs  by  the 
immobility  of  the  eoxse.    In  the  Hydrous,  in 
which  all  the  legs  are  employed  in  walking,  as 
well  as  in  swimming,  the  coxaj   are  freely 
articulated    in    their    respective  acetabula, 
and  each  one  is  supported  in  part  by  the  tro- 


chantin (?),  (A),  which  is  more  developed  than 
in  the  other  insect. 

The  strength  of  the  body  depends  much  upon 
the  size  of  the  thoracic  segments,  and  the  firm- 
ness of  union  which  exists  between  them.  Thus 
in  those  species  which  are  more  especially  em- 
ployed in  walking,  in  flying,  or  in  swimming, 
the  meso-  and  meta-thoracic  segments  are  the 
largest.    If  the  insect  be  aquatic,  the  largest 
parts,  as  we  have  seen,  are  the  sternal  surface  of 
the  meta-thorax,  and  its  coxa? ;  but  if,  on  the 
contrary,  the  habits  of  the  insect  be  aerial,  then 
the  dorsal  surface  of  the  segment  is  larger  than 
the  sternal.    In  those  insects  which  are  mostly 
employed  on  the  ground  in  running  or  walking, 
as  the  Carabida,  Geutrupida,  Coprida,  and 
Lucanidte,  the  meso-  and  meta-thoracic  seg- 
ments are  often  anchylosed  together,  to  give 
greater  strength  to  the  whole  body.    This  is 
particularly  the  case  in  Lucunus  cervus  (Jig. 
388),  in  which  the  small  sternum  of  the  meso- 
thorax  (3  g)  is  firmly  auchyclosed  to  the  enor- 
mously enlarged  sternum  of  the  meta-thorax. 
The  reason  for  this  is  not  merely  to  afford 
greater  stability  to  the  meta-thorax  and  its 
wings,  upon  which  entirely  devolves  the  labour 
of  supporting  this  unwieldy  insect  during 
flight,  but  also  to  give  greater  strength  to  the 
whole  body,  during  the  efforts  of  the  insect  to 
strip  off  the  bark  from  the  smaller  roots  and 
branches  of  trees,  to  obtain  a  flow  of  the  juices 
upon  which  it  subsists.  That  such  is  the  reason 
for  this  anchyclosed  condition  of  its  segments 
is  evident  from  the  circumstance,  that  it  occurs 
not  only  in  those  insects  which  require  great 
muscular  power  during  flight,  but  also  in  those 
which  are  much  accustomed  to  laborious  efforts 
in  tearing,  in  burrowing,  or  in  running.  In 
these,  also,  the  acetabula  (2  r,  3  r),  are  exceed- 
ingly deep,  and  almost  entirely  enclose  the 
coxae  within  them,  so  that  while  the  limb  can 
be  rotated  freely  in  almost  every  direction,  a 
dislocation  of  it  is  utterly  impossible.  The  ace- 
tabula are  situated  on  each  side  of  the  poste- 
rior part  of  the  sternum,  in  each  of  the  three 
thoracic  segments,  and  in  general  are  formed 
by  an  approximation  of  the  sternum  and  epi- 
meron, and  sometimes,  also,  of  the  epister- 
num, as  in  the  Dyticus  (Jig.  384,  A).  When, 
as  in  this   instance,  the  episternum  enters 
largely  into  the  formation  of  the  acetabulum, 
the  epimeron  is  carried  backwards,  and  forms 
the  postero-lateral  boundary,  the  episternum 
the  antero-lateral,  and  the  sternum  the  anterior 
boundary,  so  that  the  acetabulum  is  formed  by 
the  junction  of  three  articulating  sutures,  and 
completely  surrounds  the  coxa.    This  consoli- 
dation of  parts  gives  an  amazing  increase  of 
strength  to  the  segment  in  which  it  occurs,  and 
is  one  of  the  circumstances  which  enables  the 
insect  to  exert  a  degree  of  muscular  power 
which  is  sometimes  truly  astonishing.    It  oc- 
curs in  general  in  the  pro-thoracic  segment,  as 
in  Lucanus,  (388,  2,)  Geotrupes,  Ateucltus,  and 
other  Lamellicornes.   A  similar  condition  of  the 
acetabula  of  the  meso-thorax  exists  also  in  the 
same  insect  (3r).    But  instead  of  the  posterior 
wall  of  the  cavity  being  formed  by  the  epi- 


918 


TNSECTA. 


Fig.  388. 


Internal  skeleton  of  Lucanus  cervus. 


meron,  it  is  formed  by  a  reflection  inwards  of 
part  of  the  anterior  margin  of  the  meta-sternum, 
(4  </,)  with  which  the  meso-sternum  lias  become 
anchyclosed,  and  the  episternum  and  epimeron 
form  the  lateral  boundary  of  the  cavity. 
The  great  strength  of  limb  required  by  insects 
for  other  purposes  than  those  of  locomotion,  be- 
longs especially  to  the  first  and  second  pair  of 
legs,  and  consequently  the  articulations  of 
these  with  the  body  are  required  to  be  most 
secure.  We  have  seen  that  in  the  aquatic  in- 
sects the  posterior  pair  are  almost  solely  em- 
ployed in  swimming,  and  in  the  terrestrial  in- 
sects they  are  in  like  manner  employed  chiefly 


in  locomotion.  The  necessity,  therefore,  for  a 
consolidation  of  the  walls  of  the  acetabula, 
into  which  they  are  inserted,  is  not  so  great  as 
in  the  preceding  instances,  and  consequently  we 
find  that  those  for  the  posterior  pair  (4  r)  are 
formed  by  the  posterior  margin  of  the  expanded 
meta-sternum  in  front,  and  the  consolidated 
margin  of  the  inferior  surface  of  the  fifth  or 
thoracico-abdominal  segment  behind,  reflected 
inwards  and  upwards,  and  loosely  articulated 
in  the  median  line  with  the  sternum,  thus  al- 
lowing of  the  freest  motion  to  the  coxa,  the 
sides  of  each  being  formed  by  the  epimeron. 
But  in  insects  which  move  with  a  sudden 
effort,  as  in  jumping,  and  in  those  that  employ 
the  hinder  legs  as  prehensile  organs,  like  the 
Coprida,  Ateuchi,  and  others,  these  legs,  like 
the  anterior  ones,  are  inserted  into  deep 
acetabula. 

The  abdomen,  or  third  division  of  the  body., 
is  entirely  destitute  of  organs  of  locomotion. 
It  contains  the  chief  part  of  the  digestive,  re- 
spiratory, circulatory,  and  generative  systems, 
and,  like  the  thorax,  is  composed  of  distinct 
segments.  These  are  nine  in  number,  if  the 
fifth  segment  of  the  body,  which  almost  disap- 
pears during  the  change  to  the  perfect  state,  be 
included.  This  segment,  however,  we  prefer 
to  consider  as  a  distinct  part,  so  that  the  abdo- 
men consists  certainly  of  eight  segments,  be- 
sides the  anal  appendages.  Each  segment  is 
formed  of  one  dorsal  and  one  ventral  plate, 
connected  at  the  sides  by  a  distinct  membrane. 
Only  five  of  these  plates  are  in  general  to  be 
observed  on  the  under  surface,  but  some  trace 
of  the  whole  number  is  always  seen  on  the 
upper,  and  also  at  the  sides  (  fig-  388).  This 
arises  from  the  circumstance  that  a  portion  of 
the  ventral  surface  of  the  first  three  segments  of 
the  larva  is  employed  in  forming  the  under 
surface  of  the  anterior  part  of  the  abdomen  of 
the  perfect  insect,  the  change  in  Coleoptera,  as 
in  other  insects,  being  carried  to  a  greater  ex- 
tent on  the  under  than  on  the  upper  surface  of 
the  body.  One  segment,  also,  the  anal  one, 
becomes  partly  removed  from  the  others  at  the 
posterior  part,  and  is  retractile  within  the  ab- 
domen, so  that  there  are  only  five  connected 
segments  to  the  ventral  surface,  but  nine  on  the 
upper.  The  form  of  the  abdomen  is  in  general 
somewhat  triangular  or  oval  in  Coleoptera,  its 
basial  part  being  of  the  same  width  as  the  tho- 
rax. Each  segment  is  freely  moveable,  the  an- 
terior part  of  one  being  retractile  within  the 
posterior  of  another.  At  the  external  margin 
of  each  dorsal  plate,  in  the  membrane  that 
connects  those  of  the  upper  with  the  under 
surface,  there  is  an  oval  corneous  ring,  the 
spiraculum,  or  breathing  orifice,  which  commu- 
nicates internally  with  the  organs  of  respiration. 
In  most  of  the  Coleoptera  the  abdomen  is  co- 
vered by  the  elytra,  but  in  some  species  it  is 
exposed,  as  in  the  oil-beetles,  rove-beetles,  and 
ear-wigs.  In  the  latter  instances  it  is  furnished 
at  its  extremity  with  strong  forceps,  which 
appear  to  be  analogous  to  parts  which  we  are 
about  to  consider  more  particularly  in  other 
insects. 


INSECTA. 


919 


In  Orthoptera  the  structure  of  the  thorax  is 
similar  to  that  of  the  Coleoptera,  but  it  is  un- 
necessary to  describe  it  more  minutely  at  pre- 
sent, a  greater  interest  being  attached  to  the 
whole  skeleton  of  those  insects  which  undergo 
metamorphoses,  more  particularly  the  Hymen- 
optera  and  Lepidoptera,  than  to  those  in  which 
these  interesting  changes  do  not  take  place. 

The  structure  of  the  thorax  in  Hymenoptera 
merits  considerable  attention,  from  the  circum- 
stance that  it  is  scarcely  yet  decided  whether  it 
be  composed  only  of  three  distinct  segments  of 
the  larva,  or  whether  a  fourth  one  enters  in  part 
into  the  composition  of  it.  We  have  seen  that 
in  the  larva  state  in  this  order  there  are  fourteen 
distinct  segments,  besides  an  anal  tubercle,  and 
that  during  the  transformations  the  body  is  con- 
stricted in  the  fifth  segment,  which  seems  to 
form  the  connexion  between  the  thorax  and 
abdomen.  According  to  the  usually  received 
opinions,  the  true  thorax  is  always  composed  of 
but  three  segments,  but  M.  Audouin  believes 
that  this  is  not  strictly  the  case  in  Hymenop- 
tera, and  has  endeavoured  to  shew  that  in  this 
order  the  posterior  portion  of  the  thoracic  region 
is  part  of  a  segment  that  belongs  to  the  abdo- 
men. Mr.  Macleay,  on  the  contrary,  contends* 
that  this  is  not  an  additional  segment,  but  is  in 
reality  part  of  the  fourth  or  meta-thoracic  seg- 
ment of  the  larva.  In  this  opinion  he  is  sup- 
ported by  Burmeister  and  Westwood,  while  the 
views  of  Audouin  are  advocated  by  Latreille 
and  Kirby  and  Spence. 

The  pro-thorax,  which  is  a  large  segment  in 
the  larva  state,  is  greatly  reduced  in  size  in 
the  perfect  insect,  owing  to  the  operation  of 
causes  which  take  place  during  the  metamor- 
phoses. But  it  is  not  so  much  reduced  as  in 
the  Lepidoptera  and  Diptera.  The  boundaries 
of  this  segment  in  Hymenoptera,  like  those  of 
the  meta-thorax,  are  a  subject  of  dispute  among 
naturalists,  owing  to  the  segment  in  the  perfect 
state  being  divided  into  two  distinct  parts,  the 
first  of  which  is  articulated  with  the  head,  and 
freely  moveable  upon  the  other,  which  is  at- 
tached firmly  to  the  meso-thorax.  The  piece 
articulated  with  the  head  is  believed  by  Kirby 
and  Spence  to  represent  the  entire  pro-thorax, 
or  second  segment  of  the  larva.  It  bears  the 
first  pair  of  legs,  and  in  the  winged  species  is 
readily  detached  from  the  other,  which  is  the 
collure  of  those  authors,  who,  on  account  of  its 
being  attached  to  the  great  meso-thorax,  believe 
it  forms  a  part  of  that  segment.  This,  as  Mr. 
Macleay  has  shewn,  is  not  the  fact,  as  is  proved 
by  the  circumstance  that  in  the  Ants  and  other 
walking  Hymenoptera  it  is  readily  removed 
from  the  meso-thorax,  and  is  united  to  the 
anterior  piece,  which  bears  the  first  pair  of  legs  ; 
while  he  suggests  that  the  reason  for  its  being 
attached  to  the  meso-thorax  in  the  flying  spe- 
cies, is  to  give  strength  to  that  segment,  and 
support  the  wings.f  We  have  convinced  our- 
selves of  the  correctness  of  this  view  of  the 
subject  by  an  examination  of  the  parts  in  Ich- 
neumon atropos,  (fig.  389,  390,)  in  which  the 

*  Zoological  Journal,  vol.  i.  p.  145,  et  scq. 
t  Op.  cit.  p.  168. 


Fig.  389. 


Ichneumon  Atropos. 

2,  pronotum  ;  3  ft,  scutum  of  meso-thorax  ;  3  c, 
scutellum  ;  3  e,  parapteron  ;  wing  ;  4  6,  scutum 
of  meta-thorax  ;  4  d,  frenum ;  4  c,  scutellum  ;  *  *, 
spiracle  ;  I,  coxa. 

two  pieces  are  freely  separable.  The  pro-scutum 
and  scutum  of  the  pro-notum  are  exceedingly 
short  and  evanescent,  as  described  by  Mr. 
Macleay  in  Polistes,  the  prse-scutum  being 
merely  a  ligamentous  membrane  that  unites 
this  segment  to  the  head.  The  scutum  is  a 
short  plate  that  forms  the  upper  surface  of  the 
anterior  portion  of  the  segment,  the  sides  being 
formed,  as  we  shall  see,  by  the  epimera  and 
episterna  (2  g).  The  posterior  piece,  the  scutel- 
lum, is  of  considerable  size  laterally  (2  A),  but 
it  is  short  on  the  upper  surface  (2),  and  is  deeply 
notched  to  fit  it  to  the  anterior  part  of  the  meso- 
notum,  its  two  sides  being  produced  into  a  some- 
what triangular  shape,  and  wedged  in  between 
the  scutum  of  the  meso-thorax  and  the  epister- 
num  on  each  side.  The  post-scutcllum  exists 
only  as  a  rudimentary  membrane,  which  assists 
to  mark  the  proper  boundary  of  the  pro-thorax, 
this  being,  as  Mr.  Macleay  has  observed,  one 
of  the  proofs  that  the  scutellum  now  described 
does  not  belong  to  the  meso-thorax,  while  the 
non-existence  of  a  similar  membrane,  or 
phragma,  between  the  two  portions  of  the  pro- 
thorax  itself,  affords  an  additional  reason  for 
considering  these  but  as  parts  only  of  one 
segment. 

The  meso-notum  is  the  most  largely  deve- 
loped portion  of  the  thorax  in  this  order,  as  in 
Diptera  and  Lepidoptera.  It  is  a  convex  elon- 
gated plate  that  covers  nearly  the  whole  of  the 
dorsal  surface  of  the  thorax.  The  prae-scutum 
is  a  vertical  piece,  developed  inwards  to  assist 
in  the  formation  of  the  pro-phragma  that  di- 
vides the  collar  from  the  scutum.  The  scutum 
(3  b)  is  broad,  convex,  and  lozenge-shaped. 
At  its  sides  are  developed  the  anterior  pair  of 
wings,  and  at  its  base,  which  is  slightly  trun- 


920 


INSECTA. 


cated,  is  an  elevated  scutellum.    It  is  marked 
on  the  median  line  by  a  longitudinal  suture, 
and  in  some  genera  by  two  others,  one  on  each 
side  of  this.    In  the  Chrysididce,  these  lateral 
markings  completely  divide  the  scutum  into 
three  distinct  pieces,  the  two  outermost  of 
which  are  those  to  which  Mr.  Macleay  has 
given  the  name  of  parapsides,  and  which  he 
somewhat  curiously  suggests  may  probably  be 
a  third  pair  of  paraptera,*  those  of  the  pro- 
thorax,  pushed  out  of  their  proper  place.  But, 
as  remarked  by  Audouin,f  in  his  notes  to  Mr. 
Macleay's  paper,  were  this  the  case,  it  would 
indeed  be  a  most  singular  displacement ;  at  the 
same  time  we  are  compelled  to  acknowledge 
that  we  hesitate  to  admit  the  explanation  which 
M.  Audouin  has  given  of  the  nature  of  these 
pieces.    He  regards  them  as  mere  divisions  of 
the  scutum,  and  not  as  elementary  parts.  If 
this  be  the  case,  other  parts  that  are  consi- 
dered as  distinct  pieces  may  with  equal  justice 
be  regarded  as  only  occasional  divisions  of 
more  important  ones.    They  seem  rather  to  in- 
dicate the  division  of  the  skeleton  into  a  much 
greater  number  of  parts  than  are  at  present 
recognized  in  it.    We  are  led  to  this  opinion 
from  the  circumstance   that  these  markings 
exist  more  or  less  distinct  in  very  many  species. 
We  have  found  them  very  distinctly  in  the 
dried  skeleton  of  Bombus  terrestris.    The  scu- 
tellum (3  c)  is  of  large  dimensions  in  most  of 
the  Hymenoptera,  and  is  usually  considerably 
elevated  above  the  level  of  the  scutum.    It  is 
in  general  of  a  triangular  figure,  and  in  many 
species  of  this  order,  as  well  as  in  some  Dip- 
tera,  is  a  marked  character  of  the  thorax  being 
often  armed  with  spines.    The  post-scutellum 
is  not  developed  externally,  but  its  position  is 
indicated  by  an  elevated  ridge,  which  is  ex- 
tended forwards  on  each  side  from  the  hinder 
part  of  the  scutellum  very  nearly  to  the  base  of 
the  anterior  pair  of  wings,  as  in  the  Diptera 
and  Lepidoptera,  and  indicates  the  boundary  of 
the  segment.    It  forms  the  meso-phrug?na,  and 
as  Mr.  Macleay  has  remarked  in  Polistes,  is 
connected  with  the  scutum  only  at  the  sides, 
being  deficient  in  the  middle  line.    The  pec- 
toral surface  of  this  segment,  the  meso-sternum, 
is    larger  in  Ichneumon  Atropos  {fig.  390) 
than  in  many  other  species.    In  form  it  is 
nearly  quadrate  (3  g).    It  covers  the  whole 
under  surface  of  the  segment,  and  is  divided 
by  a  deep  fissure  into  two  halves.    At  its  ante- 
rior margin  it  is  united  by  an  indistinct  suture 
to  a  thin  plate,  the  episternum,  (Z  J\)  that  covers 
the  front  of  this  part  of  the  segment,  and  is 
almost  hidden  behind  the  pro-thoracic  legs,  and 
it  has  sometimes  been  considered  as  forming 
part  of  that  segment.    Its  lateral  portion  passes 
upwards  posteriorly  to  the  collar  of  the  pro- 
thorax,  and  forms  a  process  that  projects  be- 
neath the  anterior  pair  of  wings,  and  above  the 
epimeron,  (3  h,)  which  is  the  chief  portion  of 
the  side  of  this  segment.    At  its  inferior  margin 
this  piece  is  united  by  an  indistinct  suture  to 
the  sternum,  at  its  anterior  to  the  episternum, 

*  Op.  cit.  p.  169.  " 

t  Annates  de  Sciences  Natuiales.  1831. 


id  at  its  posterior  it  is  articulated  witfi 
te  coxa  of  one  of  the  middle  pair  of  legs. 


Fig.  390. 


Lateral  view  of  thorax  of  Ichneumon  Atropos. 

2g,  episternum;  2  h,  epimeron  and  scutellum 
of  pro-thorax  meso-thorax  ;  3  i,  scutum  ;  3  c, 
scutellum  ;  4  d,  frenum  ;  *  stigma  ;  3  h,  epi- 
meron ;  3  g,  sternum  ;  3  f,  episternum  ;  5,  scu- 
tellum ;  4  b,  scutum  of  meta-thorax  ;  6  to  14, 
segments  of  the  abdomen. 

The  next  segment,  the  meta-thorax,  is  an  exceed- 
ingly interesting  portion  of  the  body,  owing  to 
the  varied  extent  to  which  it  is  developed  in 
the  different  Orders  of  Insects  ;  and  on  account 
more  particularly  of  the  question  that  has  been 
started,  as  to  whether  this  portion  of  the  thorax 
in  Hymenoptera  is  formed   entirely  by  the 
fourth  segment  of  the  larva,  or  whether  a  por- 
tion of  the  fifth  also  enters  into  the  composition 
of  its  posterior  part,  as  believed  by  Audouin 
and  Latreille.   According  to  Mr.  Macleay,  the 
first  piece  of  its  dorsal  surface  or  meta-notum, 
the  pra-scutum,  is  very  distinct  in  Polistes, 
while  the  scutum  is  concealed  within  the  tho- 
rax,  being   developed  inwards  to    form  a 
pliragma,  only  a  part  of  it  being  visible  la- 
terally, but  which,  as  usual,  is  connected  with 
the  posterior  pair  of  wings,  a  circumstance  that 
invariably  characterises  the  scutum  in  all  in- 
sects.   In  Ichneumon  Atropos,  the  prce-scutum 
exists  immediately  behind  the  scutellum  of  the 
meta-thorax,  and  covers  part  of  the  scutum,  intse 
(4  b,)  which,  although  much  encroached  upon 
in  the  median  line  by  the  developement  back- 
wards of  this  part  and  the  scutellum  of  the 
preceding  segments,  is  a  distinct  region  on  each 
side  of  the  meta-notum,  and  gives  origin  to  the 
posterior  pair  of  wings.    This  sufficiently  iden- 
tifies the  part  as  the  proper  scutum,  otherwise 
it  might  be  mistaken  for  the  pra-scutum  of 
Polistes,  which  is  considerably  more  developed 
than  in  Ichneumon  Atropos.    But  the  greater 
part  of  the  scutum  is  developed  inwards,  and 
forms  a  deep  cleft  or  incision,  that  divides  the 
segment  into  two  parts  transversely,  the  poste- 


INSECTA. 


921 


rior  portion  of  which,  according  to  Mr.  Ma- 
cleay,  is  the  proper  scutellum  (5)  enormously 
enlarged,  while  Audouin  regards  it  as  being 
the  dorsal  surface  of  the  fifth  segment  of  the 
larva,  so  that,  if  the  latter  opinion  be  correct, 
the  thorax  of  Ilymenoptera  must  be  composed 
of  four  instead  of  three  segments.    We  must 
confess  that  at  first  we  were  inclined  to  Au- 
douiri's  opinion,  more  especially  on  account  of 
what  we  shall  presently  find  in  Lepidoptera, 
in  which  the  fifth  segment,  in  its  atrophied  con- 
dition, is  as  much  connected  with  the  thorax  as 
with  the  abdomen.    On  further  examination, 
however,  we  are  satisfied  that  that  portion  of  the 
meta-thorax  which  is  posterior  to  the  incisure 
belongs  to  the  third  segment  of  the  thorax  ;  but 
we  differ  from  Macleay  in  regarding  it  rather 
as  the  scutellum  and  post-scutellum  united, 
than  as  the  scutellum  alone.    Its  proper  boun- 
dary is  marked  on  each  side  of  the  segment  by 
an  elevated  ridge  or  fraenum,  (4  d,)  which  is 
extended  across  the  incisure  from  a  little  behind 
the  insertion  of  the  wings, — where  it  is  conti- 
nuous with  a  ridge  of  the  meta-notum, — as  far 
as  the  posterior  margin  of  the  acetabulum  for 
the  insertion  of  the  coxa  of  the  leg.    The  post- 
scutellum,  therefore,  may  be  regarded  as  having 
coalesced  with  the  scutellum,  and  assisted  in  the 
enlargement  of  that  part.    It  is  distinct,  but  of 
small  size  in  Pollutes,  and  is  connected  at  its 
upper  part  with  a  short  ligament,  or  funiculus, 
that  is  attached  to  the  anterior  margin  of  the 
sixth  segment  (6),  the  first  segment  of  the  ab- 
domen, which  it  assists  to  support.    But  we 
have  yet  to  trace  the  fifth  segment  of  the  larva, 
which  at  first  appears  to  be  entirely  lost.  On 
carefully  separating  or  removing  the  meta-tho- 
racic  coxae  of  Ichneumon  Atropos,  we  find  a 
very  short  plate,  reduced  almost  to  a  ligament, 
but  still  distinct  as  the  remains  of  a  separate 
segment.    It  is  the  connecting  medium  be- 
tween the  under  surface  of  the  thorax  and  ab- 
domen.   We  regard  it  as  the  remains  of  the 
ventral  plate  of  the  fifth  segment,  of  which  the 
upper  or  dorsal  plate  has  entirely  disappeared, 
or  exists  perhaps  in  an  altered  form,  as  the  fu- 
niculus just  alluded  to.    W  e  are  strengthened 
in  this  opinion  by  an  examination  of  several 
species  of  Ichneumonidte,  although  in  the  gene- 
rality of  Ilymenoptera  the  fifth  segment  ap- 
pears to  have  coalesced  with  the  sixth,  to  form 
the  petiole  or  peduncle  of  the  abdomen.  The 
meta-sternum  is  formed  of  the  same  parts  as  in 
the  preceding,  segments.    The  paraptera  are 
situated  immediately   beneath   the  posterior 
wings,  in  the  triangular  space  bounded  in 
front  by  the  epimeron  of  the  preceding  seg- 
ment, and  above  and  behind  by  the  incisure 
and  fraenum,  (  4  d,)  that  connect  the  scutellum 
with  the  scutum.  The  episternum  is  concealed 
by  the  preceding  segments,  and  the  sternum  is 
reduced  to  a  small  triangular  piece,  situated  be- 
tween the  coxae.    The  epimeron  (4  h)  is  large, 
to  give  attachment  to  the  large  coxae,  but  the 
trochantin  does  not  exist  as  a  piece  distinct 
from  the  coxa  (/),  with  which  it  appears  to 
have  become  united.    The  meta-thoracjc  or 
second  pair  of  spiracles  (**)  are  situated  in  the 
anterior  lateral  parts  of  the  scutellum.  The 


situation  of  the  spiracles  has  sometimes  been 
considered  as  indicatory  of  the  different  seg- 
ments, but,  as  remarked  by  Mr.  Macleay,  these 
parts  are  unsafe  gindes,  since  they  exist  in 
certain  segments  in  some  species,  but  not  in 
others,  and  their  situation  is  often  changed 
during  the  metamorphoses  from  the  larva  to 
the  perfeet  state.  We  have  seen  that  the  meta- 
thoracic  spiracles  of  the  larva  are  placed  at  the 
most  posterior  part  of  the  fourth  segment,  {fig. 
3.56,)  but  in  the  perfect  insect,  as  we  now  find, 
this  is  not  the  case.  If  the  situation  of  these 
parts  were  alike  in  the  two  states  of  the  insect, 
there  would  be  no  difficulty  in  identifying  the 
segments  of  the  imago  with  those  of  the  larva. 
We  believe,  however,  that  the  true  thorax  is 
formed  of  the  second,  third,  and  fourth  seg- 
ments in  all  insects,  and  that  the  fifth  segment, 
always  greatly  reduced  in  size,  and  sometimes, 
as  in  this  order,  almost  entirely  atrophied,  is 
not  in  reality  a  part  of  the  true  thorax,  but  is 
sometimes  connected  more  or  less  with  that 
region,  or  with  the  abdomen,  being  intermediate 
between  the  two.  Hence  we  have  ventured  to 
designate  it  the  thoracico-abdominal  segment. 

The  number  of  segments  in  the  abdomen  of 
perfect  Hymenoptera  appears  on  a  cursory  ex- 
amination to  vary  considerably  ;  those  in  which 
the  abdomen  is  supported  on  a  pedicle  or  foot- 
stalk having  fewer  than  others  in  which  the 
abdomen  is  of  the  same  width  as  the  thorax, 
and  the  sting  or  borer  of  the  female  is  not  con- 
cealed, as  in  Sirex  juvencus.  This  insect  on  a 
cursory  inspection  seems  to  have  nine  segments 
in  the  abdomen,  besides  a  very  large  terminal 
joint,  more  than  twice  as  large  as  any  of  the 
others,  which  is  pointed  at  its  extremity,  and 
on  the  under  surface  of  which  is  situated  the 
anal  aperture.  In  reality,  however,  there  are 
but  nine  segments  in  this  most  developed  form 
of  abdomen,  the  tenth  being  only  a  large  meta- 
thoracic  post-scutellum,  which  is  extended 
over  the  base  of  the  abdomen,  while  the  thir- 
teenth and  fourteenth  segments  of  the  larva, 
instead  of  becoming  atrophied,  as  is  usually 
the  case  in  other  insects,  during  the  metamor- 
phoses, have  coalesced  and  become  enormously 
enlarged  in  order  to  afford  sufficient  space  for 
the  muscles  required  for  the  employment  of 
the  strong  terebra  or  borer  with  which  the 
insect  penetrates  the  solid  timber  of  living  trees 
to  deposit  her  eggs.  In  the  Tenthredinida,  as 
in  Allantus  scrophularia,  there  are  nine  dis- 
tinct segments  besides  the  post-scutellum,  and 
this  is  probably  the  case  in  Athalia  centifoliic, 
although  we  can  discover  but  eight  distinct 
ones  in  that  species.  We  suspect  that  the  last 
three  segments  in  this  insect  become  united  to 
form  the  parts  connected  with  the  female  organs. 
In  the  males  there  is  the  same  number  of  seg- 
ments as  in  the  females.  This  is  also  the  case 
in  Ichneumon  Atropos  (fig.  390),  in  which  there 
are  nine  distinct  segments  to  the  abdomen 
besides  the  minute  plate  at  the  base  of  the 
sixth,  the  remains  of  the  thoracico-abdominal 
segment  before  noticed.  In  the  wasp,  hornet, 
and  bee,  only  six  segments  are  at  first  evident 
in  the  abdomen,  which  arises  from  the  circum- 
stance that  the  anal  segments,  which  form  part 


922 


INSECTA. 


of  the  organs  of  generation,  are  retractile  within 
the  abdomen.  The  sixth  segment  is  concealed, 
and  the  seventh  and  eighth  segments,  particu- 
larly the  latter,  which  is  greatly  enlarged,  form 
the  chief  portion  of  the  abdomen.  In  the 
common  honey-bee  there  appear  at  first  to  be 
but  five  segments  ;  but  one  segment,  the  sixth, 
which  forms  the  base  of  the  abdomen,  is  almost 
concealed,  and  the  others  constitute  the  sting 
and  retractile  organs  of  generation.  In  the 
male  or  drone  two  segments  are  lost  in  the 
termination  of  the  male  organs  of  generation. 
Thus,  then,  the  actual  number  of  the  segments 
is  the  same  in  all  Hymenoptera,  the  apparent 
difference  being  occasioned  by  the  retraction  of 
one  or  more  segments  within  those  which  pre- 
cede them.  To  so  great  an  extent  is  this  car- 
ried in  some  species,  as  in  the  Clirysididce,  that 
the  abdomen  at  first  sight  appears  to  be  formed 
of  only  four  segments,  the  margin  of  the  posterior 
being  armed  with  several  spines.  But  even  in 
this  family  the  number  of  segments  is  exactly 
the  same  as  in  the  Ichneumon  above  noticed, 
in  which  all  the  segments  are  apparent.  The 
five  last  segments  are  retractile  within  the 
abdomen,  and  when  extended  form  a  long 
jointed  tube,  which  is  employed  by  the  insect 
for  the  purposes  of  oviposition.  Thus  then 
the  ovipositor  of  the  Tubulifera,  the  sheath  of 
the  sting  in  the  Aculeata,  and  that  of  the  terebra 
or  borer  in  the  Terebrantia,  are  all  derived 
from  the  terminal  segments  of  the  body.  But 
we  have  already  seen  that  in  the  hymenopterous 
larva  there  is  an  additional  segment  to  the 
body,  which  from  the  existence  of  an  appa- 
rently additional  organ  in  the  perfect  insect, 
may  reasonably  be  supposed  to  be  especially 
connected  with  the  developement  of  that  part. 
On  examination,  however,  it  is  discovered  that 
it  is  not  from  the  fourteenth  or  terminal  seg- 
ment that  the  ovipositor,  or  sting,  is  entirely 
derived,  but  from  at  least  the  two  last  segments, 
the  sheath  being  developed  from  elongated 
portions  of  the  thirteenth  or  penultimate  seg- 
ment, while  the  fourteenth  forms  only  a  short 
valve  at  its  base,  like  the  extremity  of  the 
abdomen  in  Sirex.  From  these  circumstances 
it  is  evident  that  the  defensive  organs  of  the 
aculeate  Hymenoptera  are  simply  developments 
of  certain  parts  only  of  the  sides  of  the  abdominal 
segments,  while  the  tubulated  joints  of  the  ovi- 
positor of  the  Clirysididce,  with  which  there  are 
many  analogies  among  the  Lepidoptera,  are  the 
entire  segments.  It  is  evident  also  that  al- 
though the  fourteenth  segment  is  certainly  con- 
nected with  the  sting  or  borer,  it  does  not 
become  its  chief  part,  the  sheath  of  the  organ 
being  always  formed  by  parts  of  the  thirteenth 
and  sometimes  also  of  the  twelfth  segment,  so 
that  these  organs  are  simply  developements  of 
parts  which  already  exist  in  all  insects.  The 
analogues  of  the  ovipositor  are  found  in  the 
PanorpidtE  among  the  Neuroptera,  and  in  the 
Boy/tbycidiB  among  the  Lepidopteia ;  while 
those  of  the  other  forms  of  the  same  part,  the 
terebra  and  sting,  exist  in  the  exserted  oviposi- 
tors of  the  female  Gryllidie  in  the  Orthoptera, 
and  in  the  prehensile  ones  of  some  of  the 
Arcliida.  and  other  species,  in  almost  every 


instance  the  parts  being  derived  from  similar 
segments. 

In  Lepidoptera  the  size  of  the  three  segments 
of  the  thorax  is  more  unequal  than  in  Hymen- 
optera. The  prothorax  is  reduced  to  a  very  thin 
plate  or  ring,  more  especially  on  its  upper  sur- 
face or  pronotum.  On  the  prosternal  surface 
the  primary  parts,  although  greatly  reduced  fn 
size,  are  still  distinguishable.  The  prosternum 
is  a  small  square  piece,  which  is  articulated  in 
front  by  suture  with  a  part  of  the  anterior  of 
the  basal  joint  of  the  first  pair  of  legs,  and 
which  we  are  inclined  to  regard  as  the  tro- 
chantinus  (Jig-  392,  2  k).  Immediately  above 
this  is  a  short  semicircular  piece,  which  is 
perhaps  the  analogue  of  the  epimeron,  and 
which  is  united  by  suture  to  a  large  broad 
lunated  piece,  that  forms  the  greater  part  of 
the  lateral  surface  of  the  prothorax,  and  is  con- 
tinuous with  the  narrow  ring  on  the  upper  sur- 
face (Jigs.  391, 392, 2).  The  meso-notum  is  enor- 
mously developed.    The  prcEscutum  (Jig.  391) 


Fig.  391. 


Dorsal  surface  of  Sphinx  liyustri. 

is  hidden  within  the  segment  and  forms  the  pro- 
phragma,  the  anterior  boundary  of  the  segment. 
Laterally  it  is  extended  on  each  side  beneath 
the  scutum  as  far  as  the  anterior  boundary  of 
the  wings,  where  it  is  developed  on  each  side 


INSECTA. 


923 


into  a  little  inflated  eminence,  which  we  regard 
as  simply  an  extended  portion  of  the  pnescu- 
tuin  unto  which  the  parapteron  is  attached  (3  e). 
The  scutum  (3  b)  forms  a  broad  convex  plate, 
marked  in  the  middle  line  by  a  raphe.  It 
extends  from  immediately  behind  the  narrow 
ring  of  the  pronotum  on  each  side  to  the  in- 
sertion of  the  anterior  pair  of  wings,  and 
from  thence  backwards  to  a  point  opposite  to 
the  margin  of  the  posterior  pair,  thus  forming 
the  greater  portion  of  the  proper  thorax  of  the 
insect.     It  gives  attachment  on  its  internal 
surface  to  some  of  the  most  powerful  muscles 
of  the  wings,  and  consequently  requires  to  be 
more  developed  than  any  other  part  of  the 
thorax.    It  is  separated  by  a  deep  triangular 
suture  from  the  scutellum  of  the  mesothorax 
(3  c),  which  as  in  Hymenopteia  is  a  large  and 
important  part.    It  forms  the  lozenge-shaped 
posterior  part  of  the  mesothorax,  and  if  care- 
fully examined  its  angles  are  seen  to  pass  under 
the  sides  of  the  scutum,  by  the  enlargement  of 
which  it  has  been  carried  backwards.  The 
post-scutellum  (3  d)  has  almost  disappeared  ;  a 
portion  only  of  it  is  seen  on  each  side  at  the 
base  of  the  anterior  pair  of  wings,  bounded  by 
an  elevated  margin,  which  extends  outwards  to 
join  a   frcenum  that  is  connected  with  the 
posterior  margin  of  the  anterior  pair  of  wings. 
Besides  these  parts,  which  form  the  mesonotum, 
there  are  also  two  broad  moveable  plates,  the 
paruptera  (3  e),  that  cover  the  base  of  the 
anterior  pair  of  wings.    They  are  called  by 
Kirby  and  Spence  putagia,  or  tippets,  and  are 
loosely  attached  by  a  part  of  their  concave  sur- 
face to  the  little  eminences  which  we  have 
before  noticed  at  the  sides  of  the  praescutum. 
They  are  broad  arched  plates,  which  in  form 
resemble  scapulae,  and  extend  from  the  anterior 
part  of  the  scutum,  the  sides  of  which  they 
entirely  cover  as  well  as  the  insertion  of  the 
first  pair  of  wings.    They  are  always  covered 
with  long  hairs,  and  are  more  developed  in 
Lepidoptera  than  in  any  other  order.  In 
Coleoptera  we  saw  them  placed  beneath  the 
wings  on  the  anterior  part  of  the  sides  of  the 
mesothorax.     They  were  then  unimportant 
organs ;  in  Hymenoptera  they  were  removed  to 
a  position  above  the  wing,  but  in  this  order  they 
have  arrived  at  their  maximum  of  development, 
and  appear  to  be  of  great  importance  to  the 
insect.    The  meso-sternum  in  Lepidoptera  is 
a  part  of  very  difficult  examination,  and  we 
are  not  confident  that  we  have  rightly  made 
out  the  analogies  of  its  different  parts  with 
those  in  other  insects.    The  meso-sternnm  is 
greatly  reduced  in  size,  while  the  base  of  each 
leg  is  considerably  enlarged.    It  appears  to  be 
formed    by  an  union  of   the  trocliantinus 
(fig.  392,  3  k),  and  of  the  coxa  (I),  these 
parts  in  each  limb  appearing  to  be  united,  and 
distinguished  laterally  by  a  very  marked  suture. 
The  base  of  the  limbs  thus  occupies  the  greater 
part  of  the  meso-sternal  region.     The  part 
which  we  thus  regard  as  the  trochantinus  is 
articulated  in  front  with  the  sternum  (3  g),  and 
the  coxa  with  the  epimeron  (3  A).  The  sternum 
extends  upwards  on  each  side  of  the  segment 


Fig.  392. 
I 


Lateral  surface  of  Sphinx  ligustri. 

as  far  as  the  upper  portion  of  the  epimeron,  a 
little  below  the  insertion  of  the  wings.  It  is 
marked  transversely  by  a  depression  which  has 
the  appearance  of  a  suture.  At  its  anterior 
margin,  on  the  front  of  the  meso-sternum  there 
is  a  very  distinct  plate  which  is  united  to  it  by 
suture,  and  which  appears  to  be  the  proper 
episternal  piece  (3/').  The  spiracle  or  meso- 
thoracic  stigma  is  situated  in  a  little  fossa  im- 
mediately beneath  the  patagia  on  each  side 
before  the  anterior  pair  of  wings,  and  com- 
municates with  the  tracheae  between  the  pro- 
and  meso-thoracic  segments.  The  metatlwrax, 
which  bears  the  posterior  pair  of  wings,  is  con- 
siderably reduced  in  size  by  the  developement 
backwards  of  the  scutellum  of  the  meso-tborax, 
which  encroaches  upon  this  segment  poste- 
riorly, as  the  scutum  anteriorly  does  upon  the 
prothorax,  but  not  to  so  great  an  extent.  The 
prasscutum,  as  in  the  preceding  segment,  is 
concealed  within  the  thorax,  being  developed 
inwards  to  assist  with  the  post-scutellum  of  the 
preceding  segment  in  forming  the  meso- 
phragma,  while  only  a  portion  of  the  scutum  is 
visible  on  each  side  of  the  scutellum  of  the 
meso-thorax  (4  b),  where  it  forms  a  triangular 


924 


INSECTA. 


space,  from  the  sides  of  which  originate  the 
second  pair  of  wings  (*•).  It  is  hounded  pos- 
teriorly by  a  short  thick  rid;je,  the  remains  of 
the  scutellum  (4  c),  the  extremities  of  which 
pass  outwards  and  are  connected  with  the  base 
of  the  wings.  The  post-seutellum  (4  d)  is 
also  a  very  short  fold,  that  forms  the  most 
posterior  part  of  the  true  thorax.  It  is  de- 
veloped inwards  and  becomes  continuous  with 
the  remains  of  the  upper  portion  of  the  fifth 
or  thoracico-abdominal  segment  (5).  At  each 
side  it  is  connected  with  the  lateral  portions  of 
the  scutellum,  and  with  it  is  connected  to  the 
base  of  the  posterior  wings,  and  also  with  a 
membrane  or  fraenum  (5*)  that  passes  from 
the  base  of  the  posterior  wings  to  the  posterior 
margin  of  the  thoracico-abdominal  segment, 
thus  clearly  indicating  the  relation  which  this 
segment  bears  to  the  last  segment  of  the  thorax. 
The  ?netaphragma  or  septum  that  exists  between 
the  thorax  and  abdomen  is  formed  during  the 
metamorphoses  by  a  constriction  in  the  middle 
of  the  fifth  segment,  and  as  the  changes  pro- 
ceed, a  portion  of  the  fourth  segment,  the  post- 
scutellum,  is  included  in  the  fold  or  constriction, 
and  assists  to  form  the  metaphfagma,  so  that 
the  fifth  segment,  at  least  in  Lepidoptera,  is 
common  both  to  the  thorax  and  abdomen,  and 
cannot  properly  be  said  to  belong  more  espe- 
cially to  one  than  to  the  other.  Only  a  short 
portion  of  the  fifth  segment  exists  on  the  dorsal 
surface  of  the  abdomen,  posterior  to  the  thorax, 
while  the  inferior  portion,  which  was  more 
reduced  in  extent  during  the  changes  than  the 
upper,  is  reduced  to  a  very  short  piece,  which 
has  entirely  coalesced  with  the  under  surface  of 
the  sixth  segment,  the  first  true  segment  of  the 
abdomen.  In  the  meta-sternal  surface  there 
are  the  same  parts  developed  as  in  the  nieso- 
sternal,  the  arrangement  of  all  the  parts  being 
precisely  similar  to  those  of  the  meso-thorax. 
The  trockantinus  (4  A;)  is  united  with  the 
coxa  (I),  from  which  it  is  distinguished,  as  in 
the  limbs  of  the  preceding  segments,  by  a 
lateral  suture.  The  first  is  articulated  ante- 
riorly with  the  sternum  (4  g),  and  the  second 
posteriorly  with  the  epimeron  (4  h).  The 
second  or  meta-thoracic  spiracle  is  situated  in 
a  deep  cavity  behind  the  wings. 

The  abdomen  in  Lepidoptera  consists  of  nine 
distinct  segments,  or  the  remnants  of  that  num- 
ber of  the  larva  if  we  include  the  segment  which 
we  have  thus  seen  is  connected  with  the  thorax. 
We  prefer,  however,  to  consider  the  fifth  as  a 
distinct  segment,  although  a  portion  of  it  covers 
the  base  of  the  abdomen.  Each  segment  is 
formed,  as  in  other  insects,  of  two  arches,  a  su- 
perior and  an  inferior  one.  The  superior  one  is 
a  strong  corneous  plate,  and  is  equal  to  nearly  a 
complete  semicircle.  The  inferior  plate  is  similar 
in  its  form,  but  does  not  include  so  large  a 
portion  of  an  arch,  and  is  not  so  completely 
solidified.  The  lateral  margins  of  the  inferior 
arches  are  nearly  straight,  but  those  of  the 
superior  ones  are  emarginated  or  notched,  each 
notch  or  incisure  being  near  the  middle  of  the 
edge.  It  is  occupied  by  an  oval  corneous  ring, 
the  stigma  or  spiracle  which  exists  in  the  soft 


membrane  or  conjunctiva  that  connects  the 
margins  of  the  superior  and  inferior  arches  of 
the  segments.  A  similar  membrane  connects 
the  different  segments  together  longitudinally 
in  such  a  manner  that  the  anterior  margin  of 
one  segment  is  drawn  beneath  the  posterior  of 
the  one  that  immediately  precedes  it.  By  this 
arrangement  of  the  parts  of  the  segments  the 
abdomen  can  be  elongated  or  shortened  at  the 
will  of  the  insect,  and  expanded  or  contracted 
during  respiration,  which  takes  place  in  the 
abdominal  as  well  as  in  the  thoracic  region. 
There  are  nine  stigmata  or  spiracles  on  each 
side  of  the  body.  Two  of  these  we  have  seen 
are  situated  in  the  thorax,  and  the  remaining 
ones  in  the  abdomen,  from  the  sixth  to  the 
twelfth  segment ;  but  the  twelfth  is  apparently 
closed,  and  probably  does  not  take  part  in  the 
function  of  respiration,  which  is  carried  on 
chiefly  through  the  thoracic  spiracles.  It  is 
worthy  of  note  also  that  there  appears  to  be  a 
change  in  the  situation  of  one  of  the  spiracles 
during  the  transformation  of  the  larva  and  pupa 
state.  In  the  larva  a  spiracle  exists  in  the  fifth 
segment,  but  this  does  not  seem  to  be  the  case 
in  the  perfect  insect,  in  which  the  spiracle  is 
removed  forward  to  the  base  of  the  wing  in  the 
fourth,  a  circumstance  which  is  highly  interesting 
from  the  fact  that  the  wings  are  directly  con- 
nected with  the  organs  and  function  of  respira- 
tion. 

We  will  not  enter  further  upon  an  examina- 
tion of  the  thorax  and  abdomen  in  the  different 
orders,  sufficient  illustrations  having  been  given 
of  the  parts  of  which  they  are  composed,  and 
of  the  manner  in  which  they  are  developed 
from  the  almost  uniform  body  of  the  larva. 

3.  Organs  of  locomotion. —  The  wings,  the 
organs  of  flight  in  Insects,  differ  from  those  of 
Birds  in  being  supernumerary  parts  adapted 
especially  for  aerial  motion,  as  the  legs,  the 
proper  organs  of  progression,  are  for  terres- 
trial. The  wings  of  Birds  are  simply  mo- 
difications of  the  anterior  pair  of  extremi- 
ties, which  are  employed  in  most  other  Ver- 
tebrata  either  as  organs  of  prehension  or  of 
terrestrial  or  aquatic  locomotion,  and  form  parts 
of  the  normal  type  of  the  skeleton.*  But 
the  wings  of  Insects  have  no  more  analogy 
with  the  legs,  the  proper  organs  of  locomotion, 
in  the  invertebrated  than  in  the  vertebrated 
classes.  They  are  derived  entirely  from  the 
respiratory  structures,  and  have  sometimes  been 
aptly  designated  aerial  gills.  They  are  ex- 
panded portions  of  the  common  tegument  of 
the  sides  of  the  meso-  and  meta-thorax,  occa- 
sioned by  the  enlargement  and  extension  of 
numerous  tracheae  and  the  accompanying  pas- 
sages for  the  circulatory  fluids,  and  their  motions 
are  intimately  connected  with  the  function  of 
respiration.  These  trachea;  ramify  throughout 
every  part  of  the  wing,  and  immediately  after 
the  assumption  by  the  insect  of  the  imago  state 
become  solidified  like  the  rest  of  the  skeleton. 
They  are  hollow  for  the  reception  of  air  like 
the  proper  respiratory  organs  within  the  body, 

*  See  the  Article  Aves. 


INSECTA. 


925 


They  afford  strength  and  lightness  to  the  wings, 
with  which  they  are  in  direct  communication 
like  the  bones  in  the  wings  of  birds,  although 
the  organs  themselves  in  these  different  classes 
are  not  analogous.  Dr.  Leach  formerly  desig- 
nated these  solidified  trachese  in  the  wings  of 
insects  Pterigostia,  or  wing  bones,  a  name 
that  seems  appropriate,  both  on  account  of 
its  convenience  and  as  being  indicatory  of  their 
principal  function,  although  it  has  sometimes 
been  objected  to  as  incorrect  on  account  of 
their  forming  part  of  the  respiratory  system. 
But  it  may  be  remarked  that  the  true  bones  in 
the  wings  of  birds  also  communicate  with  the 
respiratory  organs,  and  perform  functions  simi- 
lar to  these  in  insects,  while  the  interesting  fact 
noticed  by  Odier,  that  in  their  solidified  con- 
dition they  are  composed  of  the  same  kind  of 
earthy  matter  as  that  which  enters  into  the 
composition  of  other  parts  of  the  skeleton,  is 
sufficient  to  warrant  us  in  retaining  the  designa- 
tion. There  appears  to  be  no  part  of  the  body 
in  vertebrata  analogous  to  the  wings  of  insects, 
except,  perhaps,  in  the  single  instance  of  one 
of  the  Saurian  reptiles,  Draco  volans,  in  which 
a  pair  of  supernumerary  organs  to  assist  in 
locomotion  are  developed  from  the  sides  of  the 
body,  and  -which  are  formed  by  the  ribs, 
directed  horizontally  outwards  and  covered  only 
by  the  skin.  We  have  thus  in  appearance  the 
remains  in  one  class  of  the  vertebrata  of  a  con- 
dition which  is  permanent  in  another  class  in 
the  invertebrata,  which  resemble  them  in  their 
general  form  and  metamorphoses.  In  every 
instance,  then,  the  wings  of  an  insect,  like 
these  appendages  of  the  thorax  in  the  reptile, 
are  perfectly  distinct  in  their  origin  from  the 
proper  organs  of  locomotion ;  they  have  their 
normal  condition  in  the  lower  invertebrata  in 
the  superior  branchial  tufts  of  the  Annelides, 
and,  consequently,  are  not  more  analogous  to 
the  wing  of  the  Bat,  as  they  have  recently  been 
supposed,*  than  to  that  of  the  Bird.  We  have 
already  seen  that  the  full  developement  of  the 
wings  takes  place  at  the  last  change  of  the 
insect,  but  it  is  commenced  in  the  earlier 
periods  of  the  larva  state,  in  which,  with  Oken 
and  Carus,  we  have  detected  these  organs  in 
their  most  rudimentary  condition.  They  are 
distinctly  seen  on  the  second  or  third  day  after 
the  insect  has  assumed  its  last  larva  covering, 
before  changing  to  the  pupa.  They  are  then 
scarcely  so  large  as  the  head  of  a  moderate 
sized  pin,  and  appear  like  newly-formed  folded 
portions  of  delicate  tegument,  extensively  sup- 
plied with  ramifications  of  minute  air-vessels, 
derived  directly  from  the  principal  trachea;. 
They  are  at  that  time  situated  immediately 
beneath  the  external  covering,  at  the  inferior 
part  of  the  sides  of  the  meso-  and  met.a-thoracic 
segments,  and  continue  to  increase  in  size 
during  the  growth  of  the  larva.  When  the 
insect  has  discontinued  to  feed,  about  a  day 
before  changing  into  the  pupa  state,  and  the 
new  skin  of  the  future  pupa  is  nearly  completed 
beneath  that  of  the  larva,  these  rudiments  of 
the  wings  have  become  so  much  enlarged  that 

*  Mod.  Clas.  Ins.  vol.  i.  p.  11. 


their  existence  is  distinctly  indicated  by  the 
swollen  appearance  of  the  segments.  It  is  at 
this  period  of  the  larva  state  that  they  were 
formerly  discovered  by  Swammerdam.*  At 
the  moment  of  Assuring  the  skin  of  the  larva, 
they  are  suddenly  somewhat  enlarged,  and 
when  the  skin  has  been  cast  off,  and  the  delicate 
parts  of  the  newly  exposed  naked  pupa  are 
beginning  to  be  agglutinated  together  and  folded 
upon  each  other  previously  to  becoming  solidi- 
fied to  form  the  strong  pupa  case,  they  again 
acquire  a  considerable  increase  of  size,  owing 
to  the  extension  and  enlargement  of  the  tracheal 
vessels  within  them,  together  with  a  corres- 
ponding increase  in  the  quantity  of  the  fluids 
in  the  circulatory  canals,  by  which  they  are 
every  where  accompanied.  The  wings  are  then 
expanded  so  as  to  cover  the  whole  under-sur- 
face  of  the  thorax  and  limbs,  and  when  the 
insect  subsequently  bursts  from  the  pupa  case 
and  is  assuming  the  perfect  state,  they  are 
again  suddenly  enlarged,  and  acquire  their  full 
expansion  through  the  recurrence  of  similar 
phenomena. 

It  is  thus  evident  that  the  wings  are  formed 
from  extensive  ramifications  of  vessels  inclosed 
between  two  membranes,  which  are  continuous 
with,  and  are  expanded  portions  of,  the  com- 
mon tegument.  In  many  instances,  as  in 
Neuroptera,  they  are  perfectly  naked,  or  are 
covered  only  with  a  few  scattered  hairs,  as  in 
Hymenoptera.  But  in  others  they  are  densely 
covered  with  peculiar  cuticular developments  in 
the  form  of  flattened  scales,  closely  imbricated 
upon  each  other,  and  inserted  each  by  a  little 
footstalk  or  quill  into  little  spaces  in  the  exter- 
nal membrane  f  In  other  instances,  as  in  the 
Coleoptera,  the  anterior  pair  become  solidified 
and  adapted  to  a  new  function,  but  are  then 
entirely  useless  as  organs  of  flight.  They  serve 
as  covers  to  protect  the  posterior  pair,  which, 
in  a  state  of  rest,  are  carefully  folded  beneath 
them ;  and  when  these  are  entirely  absent,  as 
in  some  of  the  Tcnebriunida-,  the  anterior  pair 
become  united  together  and  form  a  strong 
covering  for  the  abdomen.  Now  we  have  seen 
that  the  solidification  of  the  trachea?  alone 
affords  sufficient  strength  to  the  membranous 
wings,  which  are  always  employed  as  organs 
of  flight,  and  that  the  earthy  matter  by  which 
they  are  consolidated  is  similar  to  that  which  is 
the  means  of  consolidating  other  parts  of  the 
dermo- skeleton.  It  is  by  the  deposition  of  a 
greater  quantity  of  the  same  kind  of  earthy 
matter,  not  alone  in  the  tracheae,  but  throughout 
the  whole  substance  of  the  wings,  that  the 
anterior  pair  in  Coleoptera  are  rendered  entirely 
useless,  by  their  rigidity,  as  organs  of  flight, 
and  at  the  same  time  are  made  to  assume  a 
new  form  and  office,  and  become  the  means  of 
protecting  the  posterior  pair,  in  those  insects 
whose  habits  might  otherwise  expose  these 
necessarily  light  and  delicate  organs  to  occa- 
sional injury.  This  modification  of  structure, 
then,  in  the  form  of  elytra,  consists  simply  in 
the  solidification,  or,  if  we  may  venture  so  to 

*  Biblia  Natura,  Tab.  xxxv.  fig.  II.  e. 

f  Dr.  Roget's  Bridgewatcr  Treatise,  vol.  i.  p.  354. 


926 


INSECTA. 


call  it,  ossification  of  the  entire  organs,  and 
not  in  any  difference  in  their  normal  condition. 
In  every  instance  the  anterior  pair  of  wings,  or 
elytra,  like  the  posterior  pair,  are  formed  of 
numerous  tracheae,  accompanied  by  circulatory 
canals  extensively  ramifying  throughout  their 
whole  structure,  as  may  be  well  seen  in  the 
imperfectly  solidified  wings  of  Orthoptera  and 
Hemiptera,  and  in  the  perfectly  formed  ones  of 
many  of  the  Coleoptera,  although  it  has  some- 
times been  supposed  that  the  elytra  are  entirely 
destitute  of  these  structures.*  Excepting  in  a 
few  instances,  as  in  the  Strepsiptera,t  the  elytra 
are  almost  entirely  motionless  during  flight,  and 
are  either  simply  elevated  or  directed  horizon- 
tally in  order  that  they  may  not  impede  the 
motions  of  the  true  wings.  Thus  the  number 
and  condition  of  the  parts  employed  in  flight 
are  seen  to  vary  in  different  insects.  In  Co- 
leoptera the  posterior  wings  alone  are  actively 
employed,  in  Neuroptera  and  Hymenoptera 
both  the  anterior  and  posterior,  but  in  Hymen- 
optera the  latter  are  smaller  and  less  important 
than  the  former,  while  in  Diptera  the  posterior 
are  reduced  to  mere  appendages  of  the  atrophied 
meta-thorax,  and  the  office  of  flight  devolves 
entirely  upon  the  anterior  pair,  which  are  the 
only  ones  developed  for  such  purpose.  On  the 
other  hand,  in  some  species,  instead  of  a  reduc- 
tion in  the  number  of  these  parts,  there  is  an 
evident  tendency  to  repetition,  as  is  beautifully 
shown  in  the  existence  of  two  circular  mem- 
branous appendages  or  winglets  (alula)  deve- 
loped at  trie  inner  angles  of  the  elytra,  and 
continuous  with  the  delicate  membrane  that 
lines  the  under  surface  in  the  great  Hi/dr'uus 
and  the  Dyticida.  Similar  appendages  are 
observed  in  the  posterior  wings  of  some  Lepi- 
doptera  and  Hymenoptera,  and  in  the  proper 
wings  of  some  Diptera.  The  non-developement 
of  the  posterior  wings  in  Diptera  evidently 
seems  to  be  the  natural  result  of  the  excessive 
developement  of  the  meso-thoracic  segment, 
which  bears  the  proper  wings,  the  analogues  of 
the  anterior  pair  in  Hymenoptera,  and  the  con- 
sequent atrophied  condition  of  the  adjoining 
meta-thoracic  segment,  from  which  a  posterior 
pair  ought  to  have  been  developed.  But  that 
all  insects,  even  the  Diptera,  have  primarily 
the  same  number  of  these  organs,  is  exemplified 
in  this  order  in  the  existence  of  a  pair  of 
appendages  to  the  meta-thorax,  in  the  form  of 
little  club-shaped  bodies  denominated  halteres 
or  poisers,  and  which  exist  modified  in  form 
in  every  Dipterous  insect.  In  the  common 
gnat  they  are  simple  footstalks  surmounted  by 
a  round  knob,  attached  one  on  each  side  of  the 
atrophied  meta-thorax.  This  is  their  form  in  the 
house-fly  and  many  other  genera.  That  these  are 
the  proper  representatives  of  the  posterior  pair 
of  wings  is  now  the  opinion  of  the  most  recent 
observers,  and  is  most  decidedly  confirmed  by 
the  results  of  our  own  examinations.  They 
are  generally  more  or  less  concealed  beneath 
the  winglets,  from  which  they  are  perfectly  dis- 
tinct, being  always  connected  with  the  meta- 

*  Westwood,  Text  Book,  p.  283. 

t  Dale  in  Curtis's  British  Entomology,  fol.  226. 


thorax,  while  the  winglets  are  attached  to  the 
scutellum  of  the  meso-thorax,  and  in  some 
instances,  as  in  Tubanus  bovimis,  are  continu- 
ous with  the  margin  of  the  meso-thoracic 
wings. 

The  articulations  of  the  wings  are  formed 
upon  the  same  principles  as  those  of  the  legs, 
but  are  more  simple  in  their  construction.  Those 
at  the  proximal  extremity  of  the  cubital  ner- 
vures,  or  pterigostia,  are  of  a  somewhat  cotyloid 
form  to  allow  of  free  motion  in  several  direc- 
tions, and  often,  as  in  those  at  the  base  of  the 
elytra,  are  furnished  with  a  long  spine  or  process, 
to  which  some  of  the  powerful  muscles  are 
attached.  Those  by  which  the  wings  are 
folded  beneath  the  elytra  are  imperfectly  formed 
ginglymoid  joints  in  the  nervures,  and  seldom 
allow  of  motion  in  more  than  one  direction. 
In  most  Coleoptera,  as  in  Scarabeeida,  Hi/dro- 
philidce,  &c.  there  is  only  one  of  these  joints  in 
each  wing,  but  in  the  Bracheh/tra,  in  which 
the  wings  are  closely  packed  beneath  very  short 
covers,  there  are  often  so  many  as  four  in  each 
wing,*  while  in  other  species,  as  in  the  Bu- 
prestida,  in  which  the  wings  are  not  folded 
but  are  only  of  the  length  of  the  abdomen, 
these  joints  are  entirely  absent.  In  every 
instance  the  membranous  portions  of  the  wings 
are  either  plaited  longitudinally  or  folded  trans- 
versely when  the  wings  are  concealed  beneath 
the  elytra. 

In  the  neuration,  or  distribution  of  the  tra- 
cheae in  the  wings,  pterigostia,  which  by  the 
French  entomologists  are  called  nervures,  on  a 
casual  inspection  there  appear  to  be  many 
remarkable  variations.  But  when  the  wings 
are  attentively  examined,  it  is  found  that  there 
is  always  a  great  uniformity  in  the  distribution 
of  the  principal  nervures,  and  this  is  so  precise 
and  regular  in  many  orders  that  it  has  been 
employed  by  some  naturalists  as  strongly  cha- 
racterizing different  groups.  The  irregularity 
which  at  first  is  supposed  to  exist  in  the  dis- 
tribution of  these  nervures  in  some  families 
arises  entirely  from  the  greater  or  less  relative 
enlargement  of  the  principal  trunks  or  their 
branches.  The  characters  derived  from  these 
parts  were  formerly  employed  by  Frisch  in 
Germany  and  Harrisf  in  this  country,  but 
have  of  late  years  been  more  particularly  ap- 
plied to  the  classification  of  Hymenoptera  by 
Jurine,^  St.  Fargeau,  and  Mr.  Shuckard,  the 
first  two  of  whom  have  founded  their  arrange- 
ments of  Hymenoptera  upon  characters  de- 
rived almost  entirely  from  these  structures, 
each  of  which  they  have  designated  by  a  distinct 
name.  Mr.  Shuckard,  who  has  studied  this 
subject  with  much  care,  gives  the  following 
description  of  the  anterior  wing  in  Hymenop- 
tera^ "  The  contour  of  the  wing  is  formed 
by  its  anterior,  apical,  and  posterior  margins. 

*  Straus,  Considerat.,  &c.  p.  127. 
t  Exposition  of  English  Insects,  4to.  London, 
1782. 

J  Nouvelle  Methode  de  Classes  les  Hymenop- 
teres  et  les  Dipteres,  par  L.  Jurine,  torn.  i.  4to. 
Geneve,  1807. 

§  Transactions  of  the  Entomological  Society  of 
London,  vol.  i.  p.  209. 


INSECTA. 


927 


The  anterior  margin  is  that  portion  which  is 
situated  anteriorly  upon  its  expansion  in  flight, 
extending  from  its  base  to  its  distinctly  visible 
extremity  of  the  costal  nervure,  a  little  beyond 
the  marginal  cell ;  at  its  termination  the  apical 
'margin  commences,  and  extends  to  the  sinus 
of  the  wing,  which  is  the  incision  at  the  apex 
of  the  posterior  margin,  which  latter  extends 
from  this  sinus  back  to  the  base,  and  it  is  by 
this  margin  that  the  upper  and  under  wings 
are  connected  in  flight.  The  costal  nervure  is 
the  first  longitudinal  nervure  of  the  wing 
(Jig.  393,  a),  and,  as  we  have  seen,  extends 


Fig.  393. 


Wing  of  Hymenopterous  insect  ( Shuchwd ). 

a,  costal  nervure;  d,  post-costal;  S,  stigma; 
e,  externo  medial ;  f,  anal ;  </,  transverso-medial ; 
1,  costal  cell ;  2,  medial ;  3,  interno-medial  ;  4, 
anal  ;  h,  radial  nervure ;  5,  marginal  cell ;  6, 
cubital  nervure. 

upon  the  anterior  margin  to  just  beyond  the 
extremity  of  the  marginal  cell.  The  second 
longitudinal  nervure  is  the  post-costal  (d) ;  this 
extends  to  the  stigma  (s),  which  is  that  thick- 
ened point  or  spot  upon  the  wing  placed  upon 
its  anterior  margin  at  about  two-thirds  the  dis- 
tance of  its  base  and  extreme  apex,  and  ap- 
pears to  me  to  be  a  dilatation  of  the  costal 
nervure.  The  third  longitudinal  nervure  is  the 
externo-medial  (e),  which  proceeds  in  a  direct 
line  nearly  parallel  with  the  preceding  for  a 
little  more  than  half  the  length  of  the  post- 
costal,  or  about  one-third  of  the  entire  length 
of  the  wing,  and  then  leads  off  at  an  obtuse 
angle  to  join  the  post-costal  just  before  its 
junction  with  the  stigma.  The  anal  (f)  is  the 
fourth  longitudinal  nervure,  which  also  extends 
from  the  base  to  the  sinus  at  the  apical  ex- 
tremity of  its  posterior  margin  :  a  transverse 
nervure  unites  the  externo-medial  and  anal, 
and  which  I  purpose  calling  the  transverso- 
medial  (g).  These  nervures,  which  I  consider 
the  primary  nervures  of  the  wing,  severally 
inclose  what  have  hitherto  been  called  collec- 
tively the  basal  or  humeral  cells,  but  to  which 
I  purpose  applying  different  names  (derived 
from  the  nervures  which  inclose  them),  that 
they  may  be  more  readily  distinguished  from 
each  other.  The  first,  or  that  very  narrow  one 
between  the  costal  and  post-costal  nervures,  is 
the  costal  cell  (1);  the  second  is  that  placed 
between  the  post-costal  and  externo-medial 
nervures,  and  which  I  call  the  externo-medial 
cell  (2) :  that  inclosed  between  the  externo- 
medial  and  anal  nervures  parallelly,  and  ter- 
minated at  its  apex  by  the  transverso-medial, 
is  the  interno-medial  cell  (3);  and  the  cell 


seated  between  the  anal  nervure  and  the  pos- 
terior margin  of  the  wing  is  the  anal  cell  (4). 

"  From  the  interior  margin  of  the  stigma 
arises  the  radial  nervure  (/t),  which  makes  a 
curve  and  then  joins  the  costal  upon  the  mar- 
gin of  the  wing :  the  lanceolate  space  thus  in- 
closed forms  what  is  called  the  radial  or  mar- 
ginal cell  (5).  The  cubital  nervure  (6)  is 
nearly  parallel  with  the  radial  and  originates 
from  the  externo-medial  near  its  junction  with 
the  post-costal ;  this  extends  to  the  apical 
margin  of  the  wing  just  below  its  extreme 
apex  (6  i).  The  space  thus  inclosed  is  divided 
by  three  transverse  nervures,  which  I  propose 
calling  the  transverso-cubitals  (m,  m,  m,  m), 
inclosing  as  many  spaces  forming  so  many 
cubital  or  sub-marginal  cells,  a  fourth  being 
formed  in  consequence  of  the  nervure  extend- 
ing to  and  joining  the  apical  margin  (g).  The 
third  nervure,  originating  from  the  primary 
nervures  of  the  wing,  is  what  I  call  thedis- 
coidal  nervure  (/(),  (it  is  from  this  that  I  anti- 
cipate the  chief  results),  and  which,  commenc- 
ing at  the  transverso-medial,  extends  in  a  di- 
rect line  to  the  disc  of  the  wing  directly  be- 
tween the  stigma  and  the  sinus,  when  it  makes 
a  sudden  curve  at  a  right  angle  backwards  and 
joins  the  anal  nervure  close  to  the  sinus  (I:). 
From  this  discoidal  nervure  at  the  centre  of  its 
apical  return  another  springs,  forming  what  I 
call  the  sub-discoidal  nervure  (/),  and  which 
here  extends  to  the  posterior  margin  of  the 
wing.  From  the  cubital  nervure  two  others 
originate ;  these  are  called  the  recurrent  ner- 
vures, the  first  of  which  always  inosculates  at 
the  angle  of  the  discoidal  nervure,  and  the 
second  just  beyond  the  centre  of  the  sub- 
discoidal.  By  the  reticulation  of  these  four 
nervures  several  cells  are  formed  upon  the  disc 
of  the  wing ;  the  first  of  these,  which  is  in- 
closed between  the  discoidal  and  anal  nervures, 
I  call  the  first  discoidal  cell,  (10).  The  second 
is  that  placed  between  the  externo-medial  cubi- 
tal, first  recurrent,  and  discoidal  nervures  (11). 
The  third  discoidal  cell  is  that  inclosed  by  the 
second  recurrent,  sub-discoidal,  discoidal,  and 
first  recurrent  nervures  (12).  The  space  in- 
closed between  the  second  recurrent,  sub-dis- 
coidal, and  cubital  nervures,  and  the  pical  mar- 
gin of  the  wing,  forms  the  first  apical,  cell  (13), 
and  there  is  a  second  only  when  the  sub-dis- 
coidal nervure  extends  to  the  apical  margin, 
by  which  and  a  portion  of  the  discoidal  cell 
it  is  inclosed." 

The  distribution  of  the  nervures  in  the  wings 
of  the  males  of  some  of  the  Orthoptera  affords 
some  curious  peculiarities,  by  which  the  pteri- 
gostia  become  instrumental  in  the  production 
of  sounds.  At  the  base  of  the  superior  pair 
of  wings  in  Acrida,  at  the  inner  angle  of  each 
wing,  is  an  oval  or  nearly  circular  space 
(fig.  394,  a),  in  which  the  membrane  is  more 
transparent  and  free  from  ramifications  of  ner- 
vures than  in  any  other  part  of  the  wing. 
These  spaces  have  long  been  known  to  be  con- 
nected with  the  production  of  sound.  The 
membrane  itself  appears  to  be  thinner  than  in 
other  places,  and  more  tense,  and  the  nervures 
by  which  it  is  inclosed  are  thick  and  strong, 


928 


INSECTA. 


Fig  394. 


A 


A,  inferior  surface  of  left  wing  of  Acrida  viri- 
dissima. 

B,  upper  surface  of  the  right,  and.C,  under  sur- 
face of  left  wing  of  Acrida  brachelytra,  shewing 
the  tympanum  a,  and  bow  c,  across  which  the  file 
b  acts. 

b,  the  file  magnified. 

Until  recently  it  has  been  supposed  that  these 
were  the  only  parts  in  the  male  Acrida  con- 
cerned in  the  production  of  sound,  the  me- 
chanism of  which  has  been  explained  by  Bur- 
meister*  as  consisting  in  a  quick  attrition  of 
the  wings  against  each  other  during  a  forcible 
expiration  of  air  from  the  thoracic  tracheae  and 
spiracles,  which  are  situated  beneath,  and  are 
covered  by  the  edges  of  the  wings ;  that  the 
air  in  rushing  out  of  these  spiracles  is  driven 
against  the  tympani,  which  are  thus  occasioned 
to  vibrate  and  produce  the  sound.  But  this 
ingenious  explanation  is  not  entirely  correct; 
the  means  employed  do  not  appear  sufficient  to 
explain  the  phenomenon,  besides  which  a  part 
of  the  structure  that  is  chiefly  instrumental  in 
producing  the  sound  has  been  overlooked.  In 
addition  to  the  tympanum,  and  parts  by  which 
it  is  inclosed,  there  is  also  another  part  which 
has  not  until  recently  been  described.  It  is  a 
strong,  transversely  elongated  horny  ridge, 
situated  immediately  behind  the  tympanum, 
near  the  base  of  the  wing,  and  is  most  distinct 
on  the  upper  surface  of  the  wing  of  the  left 
side.  This  part  was  first  shown  to  us  by  the 
late  Mr.  William  Lord,  in  the  wing  of  Acrida 
viridissima,  in  February  1838,  but  it  had  pre- 

*  Manual  (translat.),  p.  470. 


viously  been  described  by  M.  Goureau,  in  an 
elaborate  paper  on  the  Stridulation  of  Insects* 
When  examined  minutely,  this  ridge,  which  is 
of  the  colour  and  appearance  of  tortoise-shell, 
is  found  to  be  striated  transversely,  so  as  to 
resemble  a  rasp  or  file.  Goureau  has  called 
it  the  bow ;  a  similar  ridge  or  file  exists  on 
the  under  surface  of  the  right  wing,  but  less 
strongly  notched,  and  is  called  by  Goureau 
the  false  bow.  When  the  wings  are  rubbed 
briskly  together,  these  rasps  or  bows  produce 
a  loud  grating  against  some  projecting  or  ele- 
vated nervures  on  the  borders  of  the  wings,  by 
means  of  which  the  drum  is  made  to  vibrate 
like  any  other  tensely  stretched  membrane 
when  agitated,  the  intensity  of  the  sounds  pro- 
duced depending  entirely  upon  the  rapidity 
and  force  employed  by  the  insect  during  the 
attrition  of  the  parts  concerned,  and  being 
entirely  independent  of  any  forcible  expiration 
of  air  from  the  thoracic  spiracles,  which  is 
thus  seen  to  be  unnecessary  for  the  production 
of  the  sound.  That  this  is  really  the  case  is 
proved  by  the  fact  that  in  Acrida  brachelytra 
(b,  c),  the  wings  are  so  exceedingly  short  and 
narrow  that  they  do  not  cover,  nor  are  they  even 
near  any  part  of  the  spiracles,  so  that  the  air  in 
passing  out  of  these  orifices  cannot  possibly  be 
driven  against  the  tympanum.  On  the  other  hand 
the  tympanum  in  this  species  (fig.  394,  B,  C) 
is  considerably  larger  than  in  others  of  the 
same  genus,  and  not  only  has  its  margins  more 
elevated,  but  has  also  a  strong  bar  extended 
across  near  its  base  (c),  is  itself  more  tense 
and  vibratory,  and  has  a  short,  strong  bar  (d), 
connected  with  the  ring  by  which  it  is  inclosed, 
and  also,  at  a  right  angle,  with  the  origin  of 
the  great  marginal  nervure  of  the  wing.  It  is 
remarkable  that  both  in  Acrida  viridissima  and 
Acrida  brachelytra,  the  tympanum  in  one  wing 
differs  from  that  of  the  other  in  being  less  re- 
gular in  its  form,  much  more  opaque,  and  tra- 
versed by  several  tracheae,  a  circumstance 
which  leads  us  still  further  to  infer  that  the 
sounds  produced  result  from  the  vibrations  of 
one  only  of  these  organs,  besides  which  the 
proper  tympani  are  not  in  corresponding  wings 
in  these  two  insects.  In  the  former,  in  which 
the  base  of  the  left  wing  is  covered  by  that  of 
the  right,  the  proper  tympanum  is  in  the  left 
wing,  while  in  the  latter  insect,  in  which  the 
right  wing  is  covered  by  the  left,  the  tympa- 
num is  in  the  left  wing,  which  is  remarkable  in 
being  entirely  deficient  of  the  file  or  bow,  but 
which  is  largely  developed  on  the  under  sur- 
face of  the  left  wing.  The  analogue  of  the 
file  in  the  right  wing  is  evidently  a  strong  por- 
tion of  the  rim  of  the  tympanum  nearest  to  the 
base  of  the  wing.  It  is  remarkable  also  that 
in  this  species  the  whole  surface  of  the  right 
wing,  in  which  the  tympanum  is  situated,  is 
more  transparent  and  free  from  nervures  than 
the  corresponding  part  of  the  left  wing,  so  that 
the  whole  surface  of  the  wing  may  perhaps  be 
rendered  sonorous.    It  is  remarkable  also  that 

*  Annates  de  la  Societe  Entomologique  de France, 

1837,  p.  31.     Entomological  Magazine,  January, 

1838,  p,  89  et  seq. 


INSECTA. 


929 


in  newly  developed  specimens,  particularly  in 

Acrida  viridissima,  the  teeth  or  markings  on 
the  file  are  more  distinct  than  in  those  which 
have  been  a  longer  time  in  the  perfect  state,  in 
which  the  teeth  appear  as  if  partially  oblite- 
rated by  use.  The  sounds,  as  remarked  by 
M.  Goureau,  may  be  readily  produced  in  the 
dead  insect  by  gently  rubbing  the  bases  of  the 
wings  together,  a  further  proof  that  the  rushing 
of  air  from  the  spiracles  is  totally  unconnected 
with  their  production.  A  similar  structure 
exists  in  the  wings  of  Acrida  grisea  and  others 
of  the  same  genus.  In  the  Achetida  the  parts 
for  stridulation  are  somewhat  differently  con- 
structed. The  wing  of  the  common  house- 
cricket,  Acheta  domestica,  differs  materially  in 
the  two  sexes.    In  the  male  (Jig.  395)  the  two 


Fig.  395. 


Wing  of  the  male  House- Cricket,  Acheta  domestica, 
shewing  the  file,  b,  and  tympanum,  a. 

wings  exactly  resemble  each  other,  and  the 
nervures  are  more  irregularly  disposed  than  in 
the  female,  in  which  they  are  arranged  either 
longitudinally  or  diagonally  with  but  very  few 
that  run  in  a  transverse  direction.  When  the 
wing  of  the  male  is  attentively  examined, 
near  ly  one-half  of  its  surface  is  found  to  be 
adapted  to  perform  the  office  of  a  tympanum. 
This  part  is  more  transparent  and  elastic  than 
the  other,  and  is  crossed  by  many  nervures  in  a 
manner  somewhat  similar  to  the  tympanum  in 
Acrida  bracheh/tra.  Besides  these  there  is  on 
the  under  surface  of  each  wing  a  large  nervure, 
which  is  curved  and  placed  somewhat  trans- 
versely near  the  base  of  the  wing,  as  in  Acrida. 
It  is  the  file  or  bow,  and  is  covered  by  a  vast 
number  of  minute,  but  freely  elevated,  semi- 
circular teeth,  which  gradually  decrease  in  size 
as  they  approach  the  external  angle  of  the 
wing  (fig-  396).  The  smallness  of  the  teeth, 
and  the  extent  of  surface  over  which  they  are 
passed  when  the  two  wings  are  rubbed  briskly 
across  each  other,  is  probably  the  cause  of  the 
very  acute  sounds  produced  by  this  insect.  In 
Gryllotalpa,  which  is  said  to  produce  a  hoarse 
croaking  sound,  the  two  wings  exactly  resem- 

VOL.  II. 


Fig.  396. 

\\ 


Tlie  round  file  of  Acheta  domestica. 

ble  each  other,  as  in  Acheta.  The  nervures 
are  thick  and  strong,  and  there  is  no  distinct 
vibratory  membrane,  but  on  the  under  surface 
of  each  wing  are  a  vast  number  of  minute 
sharp-pointed  teeth  arranged  closely  together 
along  the  middle  of  the  nervures,  not  only 
upon  that  one  which  is  analogous  to  the  file  in 
Acrida  and  Acheta,  but  also  upon  three  others 
which  run  in  a  parallel  direction  with  it,  as  well 
as  on  their  transverse  or  connecting  branches, 
so  that  the  whole  of  the  nervures  at  the  base 
of  each  wing  are  covered  with  files,  which, 
when  the  two  wings  are  rubbed  across  each 
other,  produce,  owing  to  the  shortness  of  the 
nervures,  a  low  grating  sound.  We  do  not  at 
first  perceive  the  necessity  for  a  stridulatory 
apparatus  on  the  under-surfaces  of  both  wings, 
if  the  sounds  produced  result  simply  from  the 
attrition  of  the  wings  against  each  other,  and 
the  wings  have  always  the  same  relative  posi- 
tion. But  on  close  examination  it  is  found 
that,  although  in  the  Gryllida  the  right  wing 
either  constantly  overlaps  the  left  or  the  left  the 
right,  in  the  Achetide  this  is  not  the  case,  but 
that  sometimes  one  wing  and  sometimes  the 
other  in  the  same  insect  is  the  superior.  With 
regard  to  the  acuteness  of  the  sounds  produced 
by  the  house-cricket,  it  probably  depends 
much  upon  the  length  of  the  vibrating  nervures 
on  the  large  tympanum,  as  well  as  the  small- 
ness of  the  teeth  in  the  file,  as  the  hoarse 
sounds  do,  perhaps,  upon  the  shortness  of  the 
nervures  in  Gryllotalpa.  In  Locustidtc  the 
stridulation  is  not  connected  with  the  structure 
of  the  wings. 

Besides  these  various  parts  for  the  produc- 
tion of  sounds,  the  wings  of  some  insects  are 
furnished  with  others  equally  remarkable,  but 
designed  for  a  different  purpose.  These  con- 
sist of  certain  little  hooks  and  foldings  on  the 
margins  of  the  wings,  by  means  of  which  in 
some  families  the  two  pairs  are  united  during 
flight,  in  order  that  the  motions  of  these  organs 
may  be  in  perfect  unison  with  each  other.  In 
some  genera,  as  in  the  Lepidoptera,  the  males 
alone  are  provided  with  these  hook  lets,  as  was 
formerly  noticed  by  Mr.  Haworth*  in  Apatura 
Iris,  in  which  the  wings  of  the  male  are  con- 
nected at  their  base  by  means  of  a  strong  elastic 
spring,  which  arises  from  the  base  of  the  costal 

*  Lepidoptera  Britannica,  8vo.  Lontlini,  1803. 

3  )' 


930 


INSECTA. 


nervure  of  the  inferior  wing,  and  is  received 
into  a  socket  near  the  base  of  the  main  nervure 
on  the  under  side  of  the  upper  wing.  This 
apparatus  for  connecting  the  wings  appears  to 
give  additional  strength  to  the  insect,  since  it 
exists  only  in  those  species  which  fly  most 
rapidly,  and  continue  for  a  great  length  of  time 
on  the  wing.  But  in  those  insects  in  which 
the  body  is  very  large  in  proportion  to  the 
size  of  these  organs,  and  which  are  necessitated 
by  their  habits  to  be  constantly  abroad,  and  to 
rly  to  a  great  distance,  as  is  the  case  with  the 
Ilymenoptera,  the  means  of  uniting  the  wings 
is  more  perfect.  It  consists  not  of  a  single 
booklet,  as  in  Lepidoptera,  but  of  a  series  of 
very  minute  hooks  of  a  somewhat  spiral  form 
(Jig.  397),  and  arranged  along  a  curved  portion 


Fig.  397. 


A,  inferior  wing  of  Bombus  terrestris ;  a,  the 
costal  nervure,  on  which  arc  seated  the  hooks,  b  ; 
( c,  the  winglet)  ;  B,  the  hooks  in  the  working  bee, 
apis  mellijica. 

of  the  costal  nervure,  at  the  anterior  superior 
margin  of  the  second  pair  of  wings.  These 
hooks  are  described  by  Mr.  Kirby,*  and  are 
found  in  nearly  all  the  Ilymenoptera.  They 
are  arranged  in  a  slightly  twisted  or  spiral 
direction  along  the  margin  of  the  wing,  so  as 
to  resemble  a  screw,  and  when  the  wings  are 
expanded  attach  themselves  to  a  little  fold  on 
the  posterior  margin  of  the  anterior  wing,  along 
which  they  play  very  freely  when  the  wings  are 

*  Monographia  Apum  Anglian,  vol.  i.  tab.  13, 
fig.  19.    Ipswich,  1802. 


in  motion,  slipping  to  and  fro  like  the  rings  on 
the  rod  of  a  window  curtain.  The  form  of 
the  hooks  is  very  similar  throughout  the  whole 
order,  each  hook  being  twisted  at  its  extremity 
a  little  to  one  side  and  recurved.  They  are 
always  situated  at  the  same  part  of  the  wing, 
but  vary  in  number  in  different  genera,  and 
even  in  the  sexes.  In  Urocerida,  Sirex  juvcn- 
cus,  they  are  few  and  scattered  along  the  margin 
of  the  wing,  and  this  is  also  the  case  in  Tri- 
c/iiosoma,  but  we  have  found  them  far  more 
numerous  in  Ichneumon  Atropos.  In  the 
sterile  female  or  worker  of  the  common  wasp, 
Vespa  vulguris,\ve  have  found  them  very  strong, 
and  about  twenty  in  number,  besides  five  stiff 
spines  which  are  not  bent  in  the  form  of  hooks. 
In  most  instances,  particularly  in  the  Bombi, 
the  hooks  are  less  numerous  in  the  males  than 
in  the  females.  Thus,  in  the  male  of  Bombus 
terrestris  there  are  but  eighteen  in  each  wing 
in  the  male,  but  twenty-five  in  the  fertile 
female.  In  the  male  of  Bombus  lapidarius 
there  are  only  eighteen  in  each  wing,  and  there 
is  the  same  number  in  the  worker  or  sterile 
female,  but  there  are  twenty-three  in  each  wing 
of  the  fertile  female.  In  Anthophora  retusa  there 
are  only  twenty  in  the  male,  but  twenty-two  in 
the  female.  In  Osmia  there  are  twelve  in  the 
male  and  fifteen  in  the  female.  But  the  reverse 
is  the  case  in  Anthidium  municatum,  in  which 
there  are  thirty  in  the  male,  but  only  twenty- 
five  in  the  female.  In  Megachile  there  are 
sixteen  in  the  female,  but  in  the  cuckoo-bee, 
Melecta  punctata,  there  are  thirteen  hooks  and 
four  imperfectly  developed  spines.  In  the 
male  of  Eucera  longicornis  there  are  only 
thirteen  hooks,  but  in  the  female  twenty-three, 
while  in  the  female  Calioxys  conica  there  are 
only  twelve.  In  the  queen  or  fertile  female  of 
the  common  hive-bee  there  are  only  seventeen 
slender  hooks,  arranged  at  some  distance  apart, 
and  different  in  their  appearance  from  those  of 
the  common  humble-bee.  In  the  sterile  female 
or  worker  there  are  nineteen,  but  in  the  heavy 
male,  or  drone,  there  are  twenty-one.  In  the 
male,  as  in  the  fertile  female,  of  the  hive-bee, 
the  hooks  are  placed  further  apart,  and  are  more 
slender  than  in  the  workers,  besides  which  they 
are  differently  shaped  in  the  neuter,  in  which 
each  hook  has  also  a  little  tooth  near  its  apex. 
On  reviewing  this  difference  in  the  number  of 
hooks  in  the  two  sexes,  we  are  certainly  con- 
firmed in  the  opinion  that  it  has  some  relation 
to  the  comparative  powers  of  flight  of  the 
respective  insects,  and  is  not  a  sexual  distinc- 
tion. The  great  object  of  the  hooks  evidently 
is  to  keep  the  wings  steady  during  flight,  in 
order  that  they  may  act  in  unison,  and  thereby 
enable  the  insect  to  continue  much  longer  on 
the  wing  with  less  muscular  exertion,  because, 
when  the  two  wings  are  made  to  act  but  as  one, 
the  effort  of  flying  becomes  more  concentrated, 
and  the  wings  strike  the  air  with  greater  effect 
than  if  they  were  separated  or  but  imperfectly 
connected.  It  is  well  known  that  the  males  of 
the  humble-bees,  Bombi,  are  much  feebler  on 
the  wing  than  the  fertile  females,  and  it  is  the 
same  with  the  individuals  of  the  genus  Osmia, 


INSECTA. 


931 


and  perhaps  also  with  those  of  Anthophora,  in 
which,  although  the  flight  of  the  males  is  as 
rapid  as  that  of  the  females,  we  suspect  that  it 
is  not  so  long  continued.  But  in  Anthidium 
mankatum  the  number  of  hooks  is  in  corres- 
pondence with  the  apparently  greater  power  of 
wing  in  the  male,  which  pursues  his  partner 
unceasingly,  and  darts  down  upon  her  with 
great  rapidity  at  the  season  of  connubiality. 
A  similar  remark  is  applicable  to  the  male  of 
the  hive-bee,  which  at  the  period  of  swarming 
is  exceedingly  active,  and  constantly  on  the 
wing  in  the  open  air,  in  search  of  the  queen  or 
solitary  female,  who  leaves  the  hive  but  for  a 
few  hours  on  the  first  or  second  day  after 
swarming.  Now  we  have  seen  that  the  number 
of  hooks  in  these  males  is  greater  than  in  the 
females,  and  that  their  powers  of  flight  are 
also  greater,  and  that  in'the  Bumbi  the  reverse 
is  the  case  with  regard  to  both  these  circum- 
stances. Consequently  it  is  but  fair  to  infer 
that  the  number  and  strength  of  the  hooks  are 
in  direct  relation  to  the  powers  of  the  insect. 

We  have  before  remarked  that  the  different 
forms  and  appendages  of  the  body  are  invariably 
the  result,  not  of  the  introduction  of  new 
elements  into  the  composition  of  parts,  but 
of  the  greater  or  less  extent  to  which  those 
primary  parts  are  developed.  There  is  a  beau- 
tiful illustration  of  this  principle  in  the  develop- 
ment of  the  hamuli,  which  are  only  spinous 
processes  often  observed  on  the  wings  of  other 
insects.  In  proof  of  this  we  need  but  examine 
the  wing  of  the  common  working-bee,  in  which 
there  are  several  of  these  spines  arranged  in 
a  line  with  the  hamuli,  and  inserted  in  a  similar 
manner  into  the  nervure  of  the  wing  upon  which 
the  hooks  are  situated.  In  some  instances  the 
transition  of  form  from  that  of  spines  to  hooks 
is  distinctly  marked.  Those  which  are  most 
distant  from  the  proper  hooks  retain  the  perfect 
form  of  spines,  while  those  which  are  nearest 
are  bent  in  the  same  direction,  but  to  a  less 
extent  than  the  pruper  hook,  but  sufficiently  so 
to  mark  very  distinctly  their  proper  analogy. 

In  Hemiptera,  instead  of  being  connected  by 
hooks  as  in  IJymenoptera,  the  whole  margin 
of  a  portion  of  the  anterior  wing  is  hooked  over 
a  corresponding  recurved  part  of  the  posterior, 
as  formerly  noticed  by  Chabrier*  in  the  Pentu- 
tomida.  In  the  Ilomoptera  the  wings  are  con- 
nected in  the  same  manner  as  in  Hemiptera,  as 
noticed  by  Mr.  Ashlonf  in  Membracis  curnuta. 
This  is  also  the  case  in  other  Ilomoptera.  Thus 
in  Tettigonia  bifasciata  there  is  a  triangular 
membranous  process  extending  from  the  anterior 
margin  of  the  inferior  wing,  and  which  on  its 
distal  border  is  furnished  with  four  very  dis- 
tinct but  exceedingly  minute  hooks,  resembling 
those  of  Hymenoptera.  This  process  of  the 
posterior  wing  is  curved  a  little  upwards  and 
received  into  a  fold  of  the  posterior  margin  of 
the  anterior  wing.  There  is  a  similar  structure 
in  the  wing  of  Cercopis  sanguinolenUi,  with 
this  difference,  that  the  hooks  are  very  indis- 

*  Sur  le  Vol  des  Insectes. 

t  Proceedings  of  the  Entomological  Society  of 
London  in  Transactions,  vol.  ii.  p.  20. 


tinct,  while  the  triangular  process  of  the  wing 
is  more  pointed  and  hooked  upwards.  In 
Tettigonia  spumaria  the  structure  is  exactly 
the  same.  In  lassus  viridis  the  triangular 
process  is  shorter,  but  more  extended  along 
the  costal  margin  of  the  wing,  and  is  furnished 
with  a  great  many  very  minute  imperfectly  de- 
veloped hooks,  which  attach  themselves  to  the  4 
folded  linear  margin  of  the  anterior  wing. 

The  legs,  the  proper  organs  of  locomotion, 
are  constantly  six  in  number  in  every  order  of 
insects,  but  are  subject  to  much  variety  of  form. 
Each  leg  is  composed  of  five  distinct  parts. 
First,  (jig.  332  and  398,)  the  coxa  (a)  or  basial 


Fig.  398. 


Legs  of  insects,  from  Barmeister,  Curtis,  and  Hope. 


joint,  which  is  inserted  into  the  acetabulum, 
and  connects  the  limb  with  the  thorax.  Of 
this  part  the  trochantin  is  believed  to  be  an 
appendage.  Secondly,  the  trochanter,  a 
minute  joint  attached  to  the  extremity  of  the 
coxa.  It  is  not  lettered  in  our  figure  of  the  leg 
(jig.  332,  3,  4),  but  is  placed  between  the 
coxa  and  the  third  portion  of  the  limb,  the 
femur  (b),  with  which  it  is  freely  articulated. 
The  femur  is  the  proper  thigh  of  the  insect,  and 
in  general  is  of  considerable  size.  It  is  con- 
nected by  ginglymoid  articulation  to  the  fourth 
portion  of  the  limb,  the  tibia  (c),  which  is 
usually  a  long  slender  joint,  at  the  extremity  of 
which  is  articulated  the  fifth  and  last  portion, 
the  tarsus  (d).  This  part  is  always  composed  of 
several  distinct  joints,  varying  in  number  in 
different  insects  from  two  to  six.  The  more 
common  number  is  five.    These  are  the  pri- 

3  p  2 


932 


INSECTA. 


mary  divisions  of  the  leg,  connected  together 
by  distinct  articulations,  and  in  the  most  de- 
veloped condition  of  the  limb  are  almost  in- 
variably found  in  every  insect.  The  articu- 
lation of  the  coxa  with  the  acetabulum  is 
either  ginglymoid,  as  in  the  Lamellicornes  and 
many  others,  or  cotyloid,  as  in  most  of  the 
Rhinchophora ;  that  between  the  coxa  and 
trochanter,  and  between  the  trochanter  and 
femur,  is  chiefly  of  the  former  kind,  which 
also  invariably  exists  between  the  femur  and 
tibia,  while  the  articulations  of  the  different 
joints  of  the  tarsus  with  one  another,  and  also 
with  the  tibia,  are  almost  invariably  cotyloid, 
as  in  Lucanus,  except  in  the  four  posterior  legs 
of  the  Ilydradephaga  and  other  water  insects, 
in  which  they  are  usually  ginglymoid,  because 
the  tarsi  of  these  insects  being  used  chiefly  for 
one  purpose,  that  of  swimming,  this  form  of 
joint  appears  to  be  necessary  to  give  greater 
strength  to  the  tarsus,  which  is  employed  to 
strike  the  water  almost  wholly  in  one  direction. 

Although  the  number  of  joints  in  the  tarsus 
varies  in  different  insects,  it  is  very  constant  in 
some  families,  which  are  also  connected  by 
other  circumstances.  Thus  in  a  large  group  of 
the  Coleoptera  the  tarsi  are  invariably  com- 
posed of  five  joints,  besides  a  terminal  claw, 
and  upon  this  character  they  have  been  formed 
into  one  group,  the  Pentumera ;  while  in 
another,  the  Heteromera,  there  are  constantly 
five  joints  in  each  tarsus  of  the  pro  and  meso- 
thoracic  legs,  but  only  four  in  each  of  the  two 
metathoracic.  This  tendency  to  the  production 
of  the  full  number  of  joints  is  remarkably 
shewn  in  many  instances.  Thus  in  a  large 
number  of  families,  Pseudo-tctramera,  in  which 
on  a  cursory  examination  there  appear  to  be 
only  four  joints  in  each  tarsus,  it  is  found  on  a 
closer  inspection  that  a  fifth  joint  actually  does 
exist,  in  the  form  of  a  very  minute  articulation 
(Jig.  398,  A,  4),  at  the  base  of  the  terminal 
joint  in  each  tarsus.  So  again  in  another  group, 
Pseudo-trimera,  in  which  there  appear  at  first 
to  be  only  three  joints  in  each,  it  is  found  that 
there  are  actually  four  (B,  3),  the  additional 
joint  being,  as  in  the  preceding  instances,  de- 
veloped at  the  base  of  the  terminal  one,  but 
more  distinctly  than  in  the  Pseudo-tetramera. 
This  tendency  to  a  reproduction  of  parts  is 
also  shewn  in  the  claws  at  the  extremity  of  the 
tarsi.  In  many  Coleoptera,  as  in  the  Melolon- 
th'ulie  (C),  each  claw  is  double;  while  in 
others,  as  in  Lucanus,  in  which  the  proper 
claw  is  simple,  and  articulated  to  the  terminal 
joint  of  the  tarsus,  there  is  also  an  unguicula 
or  little  claw,  supported  upon  a  distinct  joint, 
which  is  articulated  separately  from  the  proper 
claw,  with  the  last  joint  of  the  tarsus,  in  the 
middle  line  below  the  larger  one. 

The  variations  that  occur  in  the  form  of  the 
parts  of  the  leg,  as  in  other  parts  of  the  body, 
are  directly  referable  to  the  habits  or  necessi- 
ties of  the  insect.  Thus  where  the  legs  are 
employed  chiefly  in  running,  as  in  the  Ci- 
cindclida,  Carabida,  Scaritides,  and  Hurpulidce, 
they  are  usually  long  and  slender,  particularly 
the  tarsi  and  tibia; ;  the  coxse  are  very  freely 
articulated  with  the  body,  and  the  trochanters, 


particularly  those  of  the  hinder  pair  of  legs, 
are  remarkably  large.  But  when,  as  in  the 
Gyrinidee,  Dyticida,  and  Hydrop/iilida,  they 
are  employed  entirely  in  swimming,  they  are 
long,  as  in  running  insects,  and  the  tarsi  of  the 
second  and  third  pairs  are  flattened  and  broad 
like  oars,  and  their  margins,  apparently  to  in- 
crease the  breadth  of  their  oar-like  form  in  the 
water,  without  the  inconvenience  of  an  actual 
enlargement  of  the  limbs,  are  densely  clothed 
with  long  stiff  hairs  (K).  Besides  this,  the 
posterior  pair,  on  which  the  chief  action  of 
swimming  depends,  are  much  longer  than  the 
others,  and  the  tarsi  are  ciliated  to  the  very 
articulation  of  the  unguis.  The  extremity  of 
each  tibia  is  also  armed  with  one  or  more  long- 
spines,  which  may  assist  the  insect  perhaps  in 
burrowing  into  the  mud.  When  the  legs  are 
employed  simply  in  walking,  and  the  motions 
of  the  insect  are  slow,  the  legs  are  all  of  the 
same  length,  and,  as  in  the  Chrysomelida,  are 
often  covered  on  the  under  surface  of  the 
tarsi  with  little  hairy  cushions,  pulvilli.  These 
are  generally  present  also  in  climbing  insects. 
In  the  common  house-fly,  and  others  of  the 
same  genus,  instead  of  hairy  cushions  the  ter- 
minal joint  of  each  tarsus  is  furnished  near 
its  extremity  with  two  funnel-shaped  mem- 
branous suckers  (E),  by  means  of  which  the 
insect  is  enabled  to  adhere  to  smooth  surfaces, 
and  suspend  itself  in  an  inverted  position. 
Each  of  these  is  concave,  and  covered  by  a 
membrane,  and  the  manner  in  which  the  in- 
sect attaches  itself  is  by  exhausting  the  air 
beneath  each  sucker.  The  cushions  are  parti- 
cularly large  in  those  anomalous  insects  the 
Strepsiptera,  in  which  they  form  a  broad  heart- 
shaped  surface  to  each  joint  of  the  tarsi  (M). 
They  are  also  present,  but  in  a  less  perfect 
form,  in  some  of  the  running  insects,  the  Cicin- 
delida  and  Carabidte,  as  in  Dioryche  torta* 
(Mac'sL.),  in  which  the  joints  of  the  anterior 
tarsi  are  furnished  with  a  little  hairy  cushion. 
But  in  these  families  the  tarsi  of  the  anterior 
legs  of  the  males  are  always  enlarged  for  the 
same  purpose  as  in  the  Dyticida,  that  of  more 
securely  attaching  themselves  to  the  female. 
This  is  also  the  case  in  Hydrous,  in  which  the 
terminal  joints  of  the  anterior  tarsi  {fig.  330,  A) 
are  very  much  dilated.  In  the  Dyticida 
the  first  three  joints  of  the  anterior  tarsi  are 
consolidated  together,  and  form  a  broad  cir- 
cular disc,  covered  with  many  minute  funnel- 
shaped  suckers,  two  or  three  of  which  are 
much  larger  than  the  others;  in  some,  as  in 
Hyderodes  Shuckardi,  Hope,!  a  New-Holland 
species  (H),  all  the  suckers  are  of  nearly  the 
same  size.  They  exist  also  in  the  first  three 
joints  of  the  second  pair  of  tarsi  (I).  A  some- 
what similar  structure  exists  in  the  males  of 
some  of  the  sand-wasps,  Crubronida  (F).  It  is 
supposed  to  be  designed  for  the  same  purpose 
as  in  the  Dytkidce.  But  in  those  insects  it 
consists  of  a  broad  and  slightly  convex  dila- 
tation of  the  anterior  tibia;,  and  not  of  the 

*  Coleoptevist's  Manual,  Part  ii.  tab.  2.  fig. 
4,  d. 

f  Op.  cit.  pi.  3,  fig.  5.  a.  b. 


INSECTA. 


933 


tarsi,  as  in  the  latter  instances.*  Those  insects 
which  support  themselves  upon  the  surface  of 
water,  as  the  common  gnat,  have  the  under 
surface  of  each  tarsus  covered  with  rows  of 
line  hairs,  which  repel  the  water,  and  support 
the  insect  upon  the  surface.  If  the  under  sur- 
face of  the  tarsi  be  wetted  with  spirits  of  wine, 
the  insect  can  no  longer  support  itself  upon 
the  surface,  but  immediately  sinks  dovvn.f 
When  the  legs  are  employed  in  jumping,  as  in 
Haltica,  the  destructive  flea-beetle  of  the 
turnip,  and  the  Gryllida  and  Locust  id  a,  the 
posterior  pair,  upon  which  devolves  the  greatest 
effort,  as  in  the  swimming  insects,  are  con- 
siderably larger  than  the  others;  the  thighs  in 
particular  are  enlarged  and  lengthened,  to 
allow  room  for  the  insertion  of  the  muscles. 
But  when  the  legs  are  employed  in  digging  or 
burrowing,  it  is  the  anterior  pair  that  become 
the  most  important,  as  in  the  mole-cricket, 
Gryllotalpa  (G).  In  that  insect  the  coxa  («) 
is  of  an  enormous  size,  and  the  trochanter  at- 
tached to  its  inferior  margin  consists  of  two 
distinct  articulations,  one  of  which  projects  in 
a  lobulated  form,  and  probably  is  useful  in 
assisting  to  remove  the  earth  during  the  ope- 
rations of  the  insect.  The  femur  (6)  is  short 
and  broad,  and  is  articulated  both  to  the  coxa 
and  trochanter,  and  thus  derives  additional 
strength  from  its  more  secure  connexion  with 
the  base  of  the  limb  ;  while  the  tibia  (c),  which 
is  the  part  immediately  employed  in  burrow- 
ing, is  also  short,  and  divided  at  its  extremity 
into  four  strong  curved  spines,  directed  out- 
wards, and  forming  as  it  were  a  broad  hand, 
like  the  claw  of  the  mole,  for  digging  into  and 
rapidly  removing  the  earth  in  its  burrow.  The 
tarsus  id),  which  appears  to  be  almost  useless 
in  these  subterranean  labours,  consists  of  three 
short  articulations,  which  are  attached  to  the 
external  surface  of  the  tibia.  A  similar  con- 
formation of  the  tibia  exists  in  other  burrowing 
insects,  since  it  is  always  this  part  of  the 
limb  that  is  employed  in  digging,  and  not  the 
tarsus,  which  is  used  only  in  scraping  or 
scratching  away  loose  soil,  as  by  the  oil-beetles, 
Meloe,  and  the  sand-wasps.  Thus  in  the 
Scarabaida  and  Geotrupidte  the  anterior 
tarsi  are  broad  and  dentated  laterally,  and  the 
posterior  ones  are  armed  with  strong  spines. 
In  some  genera,  as  in  the  Coprides  and 
Onthophagi,  the  extremities  are  not  only 
strongly  spined,  but  are  also  broad  and  club- 
shaped,  to  assist  them  in  penetrating  into  the 
loose  excrement  beneath  which  they  are  ac- 
customed to  burrow. 

There  are  circumstances  connected  with  the 
organs  of  locomotion  in  insects  of  considerable 
interest,  and  which  cannot  be  passed  over. 
These  are  the  aberrations  of  form  which  they 
undergo  as  a  consequence  of  incomplete  de- 
velopment, and  the  occasional  existence  of 
supernumerary  limbs,  the  result  of  an  opposite 
tendency  in  the  development  of  the  germ. 
We  have  already  alluded  to  the  changes  of 
form  occasioned  by  the  former  of  these  circum- 

*  Dcgccr  Memoires,  t.  ii.  p.  810,  pi.  28. 

t  Dr.  Kogct's  Biklgewater  Treatise,  vol.  i.  p.  334. 


stances,  and  we  have  now  to  notice  the  not  less 
remarkable  occurrence  of  the  latter.  Although 
every  part  of  the  body  is  subject  more  or  less 
to  these  occurrences,  the  supernumerary  parts 
are  almost  always  antenna;  or  legs.  We  do 
not  remember  a  single  instance  of  a  supernu- 
merary wing,  or  elytron,  or  organ  of  mandu- 
cation,  although  the  whole  of  these  parts  are 
occasionally  subjected  to  an  aberration  of  form 
in  consequence  of  imperfect  development. 
Many  instances  of  this  kind  are  given  by  Dr. 
Herrmann  Asmuss,*  who  has  collected  a  mul- 
titude of  facts  connected  with  this  interesting 
subject,  from  which  it  appears  that  abnormal 
forms  are  more  frequent  in  the  antenna?  and 
legs  than  in  other  parts  of  the  body.  Only 
one  instance  is  given  of  abnormal  form  of  the 
mandible  from  arrested  development,  but 
several  of  the  antenna;  and  legs.  But  the 
most  frequent  abnormal  condition  is  found  in 
the  existence  of  supernumerary  parts.  Of 
these  he  has  given  two  instances  in  which  the 
antenna  on  one  side  of  the  head  was  double. 
These  occurred  in  one  of  the  FJaleridcc,  Athous 
/lirtwijf  and  Carabus  auratv$,%  and  one  instance 
also  in  which  it  was  trifurcated,  in  Helops 
cwruleHS.§  But  it  is  remarkable  that  the  most 
frequent  occurrence  of  supernumerary  parts  is 
of  the  legs.  Of  these  Asmuss  has  collected 
eight  examples,  and  it  is  remarkable  that  in 
six  of  them  the  parts  on  one  side  are  treble. 
Of  the  two  instances  in  which  the  parts  were 
double  the  first  occurred  in  Agriotes  obscurus,\\ 
in  which  there  were  two  perfect  prothoracic 
legs  on  the  right  side  of  the  body,  connected 
with  the  sternum  by  two  distinct  coxae.  In 
the  other  instance,  which  occurred  in  Tele- 
phorus  fuscus,%  there  were  two  meso-thoracic 
legs  on  the  left  side,  connected  together,  and 
attached  by  a  single  coxa  to  the  sternum. 
To  these  we  may  add  a  third  instance,  which 
occurred  in  Chrysomela  hmmoptera,  captured 
by  Mr.  Curtis,  and  described  in  his  British 
Entomology.**  In  this  specimen  the  super- 
numerary part  is  a  tibia,  apparently  moveable, 
and  developed  from  the  extremity  of  the  femur 
of  one  of  the  hinder  pair  of  legs.  A  similar 
remarkable  condition  is  described  by  Tiede- 
mannff  as  having  occurred  in  Melolont/ia  vul- 
garis, in  which  three  tibia;  and  tarsi  originated 
from  a  single  coxa  of  the  right  metathoracic 
leg.  Asmuss  alludes  also  to  the  specimen  of 
Oryctes  nasicornis  described  by  Audouin,U  in 
which  a  similar  number  originated  from  the 
right  prothoracic  leg ;  and  to  a  second  example 
of  Melolontha  vulgaris,^  in  which  three  tibia; 
and  tarsi  originated  from  a  triangular,  spatula- 
formed  femur  of  the  right  prothoracic  leg.  In 

*  Monstrositates  Colcoptcrorum,  Riga;  et  Dornati, 
1835. 
t  Bassi. 
f  Doumcrc. 
§  Seringe. 
||  Germar. 

Bassi. 
**  PI.  111.  Apr.  1826. 

ft  Meckel's  Archiv  tiir  Physiologic,  t.  v.  1819. 
p.  125.  tab.  2,  fig.  1. 

\%  Annalcs  dc  la  Soc.  Entora.  de  France,  1834. 
5<j  Doumcrc. 


934 


INSECTA. 


another  of  the  Melolonthida,  Rhizotrogus 
custuneus,*  three  distinct  legs  originated  by 
separate  trochanters  from  a  single  prothoracic 
coxa  of  the  right  side  (Jig.  399,  A).    But  per- 

Fig.  399. 


A,  Rhizotrogus  castaneus;  B,  Scaritea  Pyrachmon  ; 
C,  legs  of  ditto  ;  E,  F,G,  different  views  of  a  treble 
tarsus  of  Carabusperforatus  (Asmuss). 

haps  the  most  remarkable  example  is  that  given 
by  Lefebvref  of  Scarites  Pyrachmon  (B),  in 
which  from  a  single  coxa  on  the  left  side  of 
the  presternum  two  trochanters  originated 
(Jig.  399,  B,  C).  The  anterior  one,  the  proper 
trochanter,  supported  the  true  prothoracic  leg ; 
while  the  posterior  one,  in  the  form  of  an 
oblong  lanceolate  body,  attached  to  the  base  of 
the  first,  supported  two  additional  legs  equally 
well  formed  as  the  true  one.  Dr.  Asmuss  has 
also  given  an  example  in  Carabus  perforatus 
of  a  treble  fifth  joint  in  the  tarsus  of  the  left 
meta-  thoracic  leg  (E,  F,  G),  in  which  all  the 
claws  of  three  distinct  tarsi  exist. 

The  principles  upon  which  the  modifications 
of  form,  and  the  existence  of  supernumerary 
parts  depend,  as  attributable  to  retarded  or  ex- 
cessive development,  have  been  particularly 
insisted  upon  by  Saint  Hilaire,  Professor  Grant, 
and  other  comparative  anatomists,  in  reference  to 
the  development  of  the  body  in  vertebrata,  and 
are  equally  applicable  to  that  of  the  invertebrata. 
That  these  aberrations  of  form  really  depend 

*  Bassi. 

t  Guerin's  Magasin  d'Entomoloizie,  fasckul.  5, 
tab.  40. 


upon  an  arrest  of  development  is  well  shown 
in  tlie  instance  we  formerly  gave  of  Geolrupes 
stercorarius  (fig.  332),  in  confirmation  of  the 
views  of  Savigny,  respecting  the  different  kinds 
of  appendages  in  each  segment  being  simply  mo- 
difications of  the  same  normal  structure.  That 
retarded  development  is  capable  of  producing 
these  aberrant  forms  we  once  satisfied  ourself 
by  experiment  made  on  a  specimen  of  Sphinx 
ligustri.  We  carefully  watched  a  larva  that 
was  about  to  undergo  its  change  into  the  pupa 
state,  and  when  it  was  beginning  to  assume 
that  condition,  retarded  its  development  by 
repeatedly  touching  and  otherwise  disturbing 
it,  the  result  of  which  was  that  the  projecting 
case  that  usually  exists  on  the  point  of  the 
perfect  pupa  of  this  insect  was  not  developed 
in  the  pupa  in  question,  which  we  still  possess, 
and  which  exhibits  an  uniform  appearance  of 
its  exterior  almost  precisely  similar  to  that  of 
Sphinx  populi.  With  regard  to  the  existence 
of  supernumerary  limbs,  it  is  presumed,  in  the 
absence  of  any  evidence  that  these  additional 
parts  exist  also  in  the  larva,  as  we  suspect  they 
do,  as  well  as  in  the  perfect  insect,  that  they  do 
not  originate  simply  by  a  greater  development 
of  one  part  than  of  another  during  the  changes 
of  the  insect,  but  upon  an  original  tendency  to 
the  production  of  them  which  existed  in  the 
germ  itself.  This  opinion  seems  to  be  supported 
by  the  circumstance,  that  although  there  is  a 
tendency  to  the  reproduction  of  the  same  parts 
as  a  normal  condition  of  the  wings  in  some 
insects,  such  reproduction  is  not  known  to  occur 
as  an  abnormal  condition,  which  appears  to  be 
accounted  for  by  the  circumstance  that  the  wings 
themselves  are  simply  developments  of  parts  of 
other  structures,  the  respiratory  organs. 

The  muscular  system  of  Insects,  like  that  of 
other  Articulata,  is  contained  within  the  dermo- 
skeleton.  It  is  composed  of  an  immense 
number  of  distinct,  isolated,  straight  fibres, 
which  are  not  constantly  aggregated  together 
in  bundles,  united  by  common  tendons,  or 
covered  by  aponeuroses  to  form  distinct  mus- 
cles, as  in  Vertebrata,  but  remain  separate 
from  each  other,  and  only  in  some  instances 
are  united  at  one  extremity  by  tendons.  The 
greater  number  of  these  fibres  are  flat,  thin, 
and  of  the  same  size  throughout  their  whole 
length,  a  few  only  being  slightly  conical.  They 
are  arranged  parallel  to  each  other,  and  form 
layers,  or  series  of  fibres.  These  series  of 
fibres,  or  layers,  we  prefer  to  regard  as  sepa- 
rate muscles,  rather  than  as  aggregations  of 
muscles,  as  they  were  formerly  regarded  by 
Lyonet,*  because  we  are  thereby  enabled  to 
simplify  our  description  of  the  muscular  sys- 
tem of  these  animals.  But  besides  these  layers 
of  fibres,  which  form  the  greater  part  of  the 
muscular  system,  there  are  also  certain  sets 
of  fibres  which  are  united  by  tendons  to  con- 
stitute distinct  muscles,  but  they  are  not  in- 
closed by  aponeuroses.  The  muscles  of  in- 
sects differ,  then,  as  remarked  by  Straus,  f  from 

*  Traite  Anatomique  dc  la  Chenille  qui  icnge 
le  bois  de  Saule,  17b'0. 

f  Considerations,  &c.  p.  145. 


INSECTA. 


935 


those  of  the  larger  animals  in  not  being  in- 
closed by  aponeuroses,  and  in  being  formed  of 
fibres  which  are  always  free,  straight,  and  fre- 
quently are  not  connected  with  or  arise  from 
tendons.    There  is  no  instance,  as  Straus  has 
correctly  remarked,  of  a  digastric  muscle  in 
insects.    Each  fibre  is  composed  of  a  great 
number  of  very  minute  fibrillar,  or  fasciculi  of 
fibrillar,  into  which  the  fibre  may  be  easily 
torn,  after  it  has  been  hardened  for  some  time 
in  spirits  of  wine.    Professor  Wagner  has  seen 
transverse  stria?  on  the  fibres  of  insects  as  on 
those  of  vertebrated  animals,  and  we  have 
also  observed  them  very  distinctly  on  the  dorsal 
longitudinal  fibres  of  Lucanus  cervus,  and 
more  particularly  on  the  fibres  of  the  longitu- 
dinal muscles  of  the  back,  in  the  abdominal 
segments  of  the  larva  of  Odonestis  potatoria  ; 
Professor  Muller  states  that  the  voluntary  mus- 
cles of  insects  are  wholly  constituted  by  these 
transversely  striated  fibres,  each  of  which  has 
a  very  delicate  sheath,  which  can  often  be  per- 
ceived forming  a  transparent  border  to  the 
fibre.*    Those  fibres  which  are  entirely  with- 
out tendons  are  attached  by  their  whole  breadth 
either  directly  to  the  flat  internal  surface  of  the 
dermo-skeleton  or  to  elevated  ridges,  which  are 
intussuscepted  portions  of  the  tegument  within 
the  body,  the  apodemata  of  Audouin,  of  which 
the  phragmata  before  described  are  examples. 
The  tendons,  or  hard  uncontractile  ends  of  the 
muscles,  like  the  phragmata,  are  formed  by  an 
elongation  inwards  of  parts  of  the  internal 
lamina  of  the  dermo-skeleton .f    They  exist 
more  generally  in  the  perfect  insect  than  in  the 
larva,  and  in  the  muscles  of  the  head  of  the 
larva  than  in  other  parts  of  the  body.  The 
cause  of  this  appears  explicable  by  the  fact  that 
there  is  a  higher  developed  condition  of  body 
in  the  perfect  insect  than  in  the  larva,  and  in 
the  head  of  the  latter  than  in  other  parts  of  its 
body.    Distinct  tendons  exist  most  frequently 
in  the  muscles  of  the  extremities  and  organs 
of  manducation,  as   in  the  Lucanus  cervus 
(Jig.  388,  2),  in  which  a  large  flat  tendon,  of 
great  strength,  is  attached  to  the  external  con- 
dyle of  the  mandible,  and  on  each  side  of 
which  the  fibres  that  compose  the  great  ex- 
tensor penniform  muscle  are  inserted.  Tendons 
exist  also  of  great  length  in  the  legs  of  Orthop- 
tera  (Jig.  409,  a,  b,  c),  and  between  the  forked 
processes  of  the  thoracic  segments,  and  the 
margins  of  the  coxa;.    The  muscles  with  ten- 
dons are  arranged  by  Straus  under  two  divi- 
sions :  I  first,  the  conical,  in  which  the  tendon 
is  short  and  occupies  the  axis  of  the  muscle, 
where  it  is  expanded  into  a  broad  plate,  unto 
which  the  fibres  of  the  muscle,  originating 
from  a  broad  base,  and  converging  to  one  point, 
are  attached,  and  the  tendon  then  proceeds 
alone  to  the  point  of  insertion ;  second,  the 
pyramidal,  in  which  the  tendon,  as  in  the 
conical,  is  surrounded  by  short  fibres,  and  is 

*  Elements  of  Physiology,  (translation,)  partiv. 
p.  882. 
f  Straus. 
X  Op.  cit.  p.  14b". 


broad  and  divided  into  several  lamina; ;  third, 
the  pseudo-penniform,  in  which  the  fibres  ori- 
ginate in  a  row,  and,  converging,  are  attached 
sometimes  on  one  side,  and  sometimes  on  both 
sides  of  a  long  narrow  tendon ;  fourth,  the 
penniform,  which  differ  from  the  last  in  the 
margin  of  the  tendon  being  fibrous.  Like  the 
latter  the  fibres  originate  sometimes  on  one 
side  only,  and  sometimes  on  both.  Fifth,  the 
compound,  or  those  which  consist  of  several 
muscles,  each  formed  of  two  or  more  fibres, 
united  by  a  tendon,  and  these  tendons  of  two 
or  more  muscles  united  into  one  bundle ;  or 
in  which  the  tendons  of  several  bundles  of 
muscles  are  united.  Unto  these  five  forms 
Burmeister  has  added  a  sixth,  the  cylindrical^ 
the  tendon  of  which  is  a  flat  round  plate,  to 
which  the  fibres  are  attached  on  one  side,  and 
from  which  a  process  extends  on  the  opposite 
to  the  point  of  insertion,  as  in  the  muscles  of 
the  wings.  Audouin  calls  these  tendons  epi- 
dhnes,  and  regards  them  as  processes  of  the 
thorax. 

The  muscles  of  the  larva  present  great  uni- 
formity of  size  and  distribution  in  every  seg- 
ment, the  motions  of  each  of  these  divisions 
of  the  body  being  almost  precisely  similar. 
The  differences  which  exist  in  the  number,  dis- 
tribution, and  functions  of  the  muscles,  are  to 
be  sought  for  in  the  first  four  segments,  which 
compose  the  head  and  thorax  of  the  perfect 
insect.    Thus,  in  the  head  of  the  larva  there 
is  a  greater  aggregation  of  muscles  than  in  any 
other  segment  of  its  body,  because  a  greater 
number  of  organs  exist,   and  consequently 
require  these  additional  muscles.    The  pre- 
sence of  a  greater  number  of  organs  in  this 
than  in  the  succeeding  segments  is  readily  ac- 
counted for,  when  we  remember  that  the  head 
is  composed  of  several  sub-segments,  and  that 
the  appendages  belonging  to  it  are  those  of 
these  originally  distinct  parts.    But  the  situ- 
ations and  the  form  of  the  muscles  have  become 
changed  from  those  of  the  simple  muscles  of  a 
segment,  and  some  have  become  united  to 
others.    This  may  explain  the  cause  of  the 
greater  complexity  of  the  muscles  of  the  head 
of  the  larva  than  of  those  of  the  other  seg- 
ments, and  why  so  few  are  simple  like  those 
of  the  abdominal  regions,    but,  on  the  other 
hand,  are  frequently  complicated,  and  end  in 
tendons,  and  more  or  less  resemble  in  form 
the  muscles  of  Vertebrata.    Hence  the  muscles 
of  the  mandibles  are  large  and  occupy  the 
greater  part  of  the  lateral  and  posterior  region 
of  the  cranium,  the  extensor  muscles  being 
attached  to  the  lateral  and  posterior  surface  of 
the  cavity,  like  the  extensor  muscles  of  the 
legs  in  the  thoracic  segments,  and  the  flexor 
more  internally  to  parts  that  correspond  to  the 
lamina  squamosa  in  the  head  of  the  perfect 
insect,  the  analogies  of  which  in  the  thoracic 
segments  are  the  forked  processes  to  which 
the  flexor  muscles  of  the  legs  are  attached, 
like  the  corresponding  muscles  of  the  man- 
dibles on  the  head.    The  muscles  of  the  three 

*_ Manual  of  Entomology,  (trans.)  p.  249. 


936 


INSECTA. 


segments  that  follow  the  head,  and  form  the 
thorax  of  the  future  imago,  are  more  numerous 
and  complex  than  those  of  the  abdomen, 
because  unto  those  segments  belong  the  mus- 
cles of  the  proper  organs  of  locomotion ;  be- 
sides which  they  contain  also  the  rudiments  of 
the  muscles  for  the  future  wings.  The  muscles 
in  the  abdominal  segments  are  fewer  and  far 
more  simple  than  in  the  anterior  part  of  the 
body,  but  their  number,  even  in  these,  very  far 
exceeds  what  at  first  might  be  expected.  So 
numerous  are  they  in  every  segment  that 
Lyonet,  in  his  immortal  work  on  the  anatomy 
of  the  larva  'of  Cossus  ligniperda,  found  two 
hundred  and  twenty-eight  distinct  muscles  in 
the  head  alone,  and,  by  enumerating  the  fibres 
in  the  layers  of  the  different  segments,  reck- 
oned one  thousand  six  hundred  and  forty-seven 
for  the  body,  and  two  thousand  one  hundred 
and  eighteen  for  the  internal  organs,  thus 
making  together  four  thousand  and  sixty-one 
muscles  in  a  single  larva.  In  the  larva  of 
Sphinx  ligustri  we  have  found  the  muscles 
equally  numerous  with  those  discovered  by 
Lyonet  in  the  Cossus,  but  in  attempting  to 
describe  them  it  has  appeared  preferable,  as 
we  have  stated,  to  consider  each  layer  of  fibres 
collectively  as  a  separate  muscle.  In  describ- 
ing the  muscles  of  the  ventral  portion  of  a 
segment,  we  formerly*  ventured  to  designate 
them  by  names  which  were  indicatory  either  of 
their  position  or  use,  and  we  shall  continue  to 
do  so  on  the  present  occasion.  A  description 
of  the  muscles  of  a  portion  of  a  segment  will 
suffice  to  convey  some  idea  of  their  multiplicity 
and  use.  We  may  first  state  generally  that 
those  muscles  which  form  distinct  layers  or  act 
in  concert  with  each  other,  are  inserted  into 
slightly  elevated  ridges  of  the  tegument,  while 
a  single  muscle,  or  the  tendon  of  many  mus- 
cles united  together,  is  attached  to  an  elevated 
process  of  the  tegument,  which  at  that  point  is 
thicker  than  in  other  places,  and  thus  affords 
a  means  of  attachment.  There  are  always 
three  ridges  for  the  attachment  of  muscles  be- 
tween two  abdominal  segments.  The  middle 
one  is  the  largest,  and  affords  both  origin  and 
insertion  to  the  straight  or  longitudinal  muscles, 
while  the  others  in  like  manner  afford  origin  and 
insertion  to  the  oblique  ones. 

On  removing  the  fat  and  viscera  from  the 
abdomen  of  the  larva,  the  first  layer  that  pre- 
sents itself,  and  forms  the  interior  parietes  of 
the  body,  consists  of  many  longitudinal  fibres, 
which  extend  from  the  margin  of  one  segment 
to  that  of  another  as  flat,  straight  muscles, 
resembling  the  recti  abdominales  of  vertebrated 
animals.  These  muscles  extend  from  the  an- 
terior margin  of  the  sternal  surface  of  the 
second  segment  to  the  posterior  part  of  the 
twelfth  ;  but  it  is  only  at  the  anterior  margin 
of  the  sixth  segment,  which  is  in  reality  the 
commencement  of  the  true  abdomen,  that  they 
can  properly  be  considered  as  recti  muscles, 
since  it  is  at  this  part  of  the  body  that  they 
begin  to  be  fully  developed.    While  passing 

*  Phil.  Trans,  part  ii.  1836. 


through  the  thoracic  segment  they  are  nar- 
rower, thinner,  and  somewhat  differently  ar- 
ranged. They  are  connected  anteriorly  with 
the  head,  and  posteriorly  with  the  sphincters-. 
They  are  the  most  powerful  of  all  the  muscles 
of  the  abdomen,  and  are  those  which  are  most 
concerned  in  shortening  the  body,  and  effecting 
the  duplicature  of  the  external  teguments, 
during  the  changes  of  the  insect.  They  are 
also  those  which  mainly  assist  in  locomotion 
during  the  larva  state.  There  are  four  sets  of 
these  longitudinal  muscles,  two  on  the  dorsal 
and  two  on  the  ventral  surface  of  the  body 
(Jig.  400,  A  A).  Those  on  the  dorsal  surface 
are  placed  one  on  each  side  of  the  dorsal  vessel 
or  heart,  and  those  on  the  ventral  one  on  each 
side  of  the  nervous  column.  The  dorsal  sets 
extend  from  their  attachment  to  the  upper  part 
of  the  head  through  the  thorax  and  abdomen 
to  the  anus?  in  the  thirteenth  segment.  In  the 
thoracic  region  they  are  narrow  like  the  cor- 
responding muscles  of  the  ventral  surface,  but 
when  the  insect  is  undergoing  its  changes  they 
become  enormously  enlarged  in  this  region, 
and  form  the  great  depressor  muscles  of  the 
wings  (jig.  402,  x),  which  are  some  of  the 
most  powerful  muscles  of  the  thorax,  and  ex- 
tend between  the  meso-andmeta-phragma.  The 
ventral  recti  consist  of  four  sets  of  fibres,  two 
on  each  side  of  the  nervous  cord  (jig-  400, 
1,2),  and  between  which  there  is  a  slight  in- 
terspace. That  set  which  is  placed  nearest  to 
the  nervous  cord  and  median  line  of  the 
body,  is  composed  of  only  three  narrow  fas- 
ciculi of  fibres,  and  may  be  called  the  recti 
minores  (2),  while  the  other  set,  situated  more 
externally  and  covering  the  greater  portion  of 
the  ventral  surface  of  the  segment,  is  broad 
and  powerful,  and  consists  of  from  twenty  to 
twenty-five  distinct  fasciculi  or  fibres,  and  may 
be  called  the  recti  majores  (1).  The  origins 
and  insertions  of  these  are  different  from  those 
of  the  smaller  recti.  The  recti  majores  of  one 
segment  arise  from  the  middle  ridge  between 
two  segments  (3),  and  are  inserted  close  to  the 
origin  of  the  corresponding  muscles  of  the 
next  segment,  while  the  recti  minores  arise 
from  the  most  posterior  of  the  three  ridges, 
about  one-fifth  of  a  segment  posterior  to  the 
middle  ridge,  over  which  they  pass,  and  pro- 
ceed in  a  direction  parallel  to  the  larger  ones 
to  be  attached  to  part  of  the  corresponding 
ridge  in  the  next  segment.  There  is  a  small 
muscle  that  originates  from  the  same  ridge  as 
the  greater  rectus,  between  it  and  the  smaller, 
which,  from  its  passing  directly  to  the  alimen- 
tary canal,  and  connecting  that  viscus  to  the 
exterior  tegument  of  the  body,  may  be  called 
the  retractor  ventriculi  (5).  There  is  one  of 
these  muscles,  as  shown  also  by  Lyonet  in  the 
Cossus,  on  each  side  of  the  nervous  cord,  from 
the  fourth  to  the  eleventh  segment.  On  re- 
moving the  recti,  we  expose  two  layers  of  very 
fine  thin  muscles.  The  upper  layer  (B)  con- 
sists of  nine  distinct  fasciculi  of  fibres,  which 
pass  backwards  and  outwards,  in  a  slightly 
diagonal  direction  (6),  but  less  diagonally  than 
the  second  layer  (7),  that  lies  immediately 


INSECTA. 


937 


Fig.  400. 


Diagram  of  the  muscles  and  nerves  of  the  ventral  surface  of  the  segments  in  the  larva  "' 
of  Sphinx  ligustri.  ( Newport,  Phil.  Trans.) 


beneath  the  upper  one.  The  second  layer  con- 
sists of  seven  distinct  fasciculi,  which  extend 
from  the  anterior  margin  of  the  segment,  close 
to  the  smaller  rectus,  and  beneath  the  larger, 
about  half  their  breadth  across  the  segment. 
They  run  backwards  and  outwards  in  a  dia- 
gonal direction,  and  are  attached  to  the  middle 
ridge  below  the  rectus  as  far  across  the  seg- 
ment as  the  outer  margin  of  that  muscle  (8). 
These  layers  of  muscles  when  in  action  draw 
the  outer  part  of  the  anterior  margin  of  the 
following  segment  diagonally  forwards  in  the 
direction  of  the  median  line  of  the  body, 
and,  consequently,  when  these  muscles  in  se- 
veral segments  on  one  side  of  the  body  act 
ogether,  they  bring  forward  the  posterior  por- 
ion  of  the  body  of  the  same  side,  and  bend 


it  in  a  semicircular  direction.  When  these 
layers  on  both  sides  of  a  segment  act  together, 
they  draw  forwards  the  posterior  part  of  the 
body  in  a  straight  line.  The  most  internal 
of  these  layers  (6)  which  lies  close  to  the  rectus 
may  be  called  the  first  oblique,  and  the  other 
the  second  oblique  (7).  Beneath  this  there  is 
another  diagonal  layer  of  fibres  which  originates 
close  to  the  median  line  of  the  body  (9),  be- 
neath the  nervous  cord,  almost  in  a  line  with 
the  insertion  of  the  smaller  rectus.  The  origin 
of  this  set  is  exceedingly  narrow  and  distinctly 
tendinous,  and  the  fibres  diverging  pass  di- 
agonally upwards  and  outwards,  forming  a  Hat 
triangular  muscle,  the  third  oblique  (9,  10), 
which  is  attached  to  the  posterior  ridge,  and 
extends  outwards  to  the  margin  of  the  greater 


938 


INSECTA. 


rectus.  These  oblique  muscles  are  the  anta- 
gonists of  the  recti,  and  when  acting  alone 
draw  the  posterior  pdrt  of  eacli  segment  back- 
wards and  to  the  median  line  ;  consequently, 
when  the  layers  of  only  one  side  are  in  action, 
the  anterior  part  of  the  body  is  flexed  laterally 
in  the  form  of  a  curve,  but  when  those  on  both 
sides  are  in  action  the  anterior  part  of  the  body 
is  carried  directly  backwards.  Beneath  these 
oblique  muscles  there  is  another,  which  is 
formed  of  only  two  broad  fibres.  It  arises 
from  the  anterior  of  the  three  ridges  of  attach- 
ment in  the  median  line,  and  passing  diago- 
nally forwards  and  outwards  parallel  to  the  third 
oblique,  beneath  its  inner  margin,  is  attached 
to  the  third  ridge  of  insertion.  This  may  be 
called  the  fourth  oblique  (11).  Beneath  the 
posterior  extremity  of  this  muscle  lies  the 
third  rectus  (12),  which  is  formed  of  three 
fibres,  somewhat  broader  than  those  of  the 
second  or  smaller  rectus,  but  running  longitu- 
dinally in  exactly  the  same  direction,  and  hav- 
ing the  same  origin  and  insertion.  On  re- 
moving the  third  rectus  we  expose  the  eighth 
layer  of  muscular  fibres.  This  arises  from  the 
anterior  ridge,  and  is  formed  of  three  broad 
fibres  which  are  partially  crossed  at  their  origin 
by  the  third  rectus.  It  passes  diagonally  out- 
wards, and  is  attached  to  the  third  ridge,  extend- 
ing as  far  as  the  margin  of  the  rectus  and  third 
oblique,  by  which  it  is  concealed.  This  is  the 
fifth  oblique  (13).  When  this  layer  is  removed, 
the  triangular  and  transverse  muscles  are  exposed. 
The  triangularis.  (14)  is  composed  of  nine  dis- 
tinct fibres,  which  originate  in  a  longitudinal 
series  that  extends  about  half-way  across  the 
segment.  The  fibres  pass  from  their  origin 
diagonally  backwards  and  outwards,  with  vary- 
ing degrees  of  obliquity,  and  are  inserted  by 
strong  tendons  into  the  anterior  of  the  three 
transverse  ridges  (16).  They  arise  also  by 
distinct  tendons,  which  indigitate  with  a  set 
of  short  transverse  fibres,  ten  in  number,  and 
which  occupy  the  median  line  beneath  the  ner- 
vous cord, and  form  the  transversus  medius  (1 5). 
This  muscle  contracts  the  diameter  of  the  mid- 
dle of  the  under  surface  of  a  segment.  The 
triangularis,  when  acting  with  its  fellow  of  the 
opposite  side,  shortens  the  posterior  half  of 
the  ventral  surface  of  the  segment;  but  when 
acting  singly,  or  in  conjunction  with  the  third 
oblique,  shortens  that  side  of  the  segment,  and 
assists  to  bend  the  body  laterally.  It  is  a  very 
powerful  muscle  in  locomotion,  and  probably 
is  of  great  use  in  shortening  and  contracting 
the  segments  during  the  transformations.  The 
transversi  ubdominalcs  (17)  are  six  short  broad 
and  thick  fibres,  that  form  two  sets,  and 
originate  at  some  distance  from  the  median 
line,  posteriorly  to  and  on  the  outer  side  of 
the  tendons  of  the  third  oblique,  and  passing 
transversely  outwards  are  inserted  directly  into 
the  tegument,  about  half-way  across  the  segment. 
Like  the  transversus  medius  they  contract  the 
diameter  of  the  ventral  surface  of  the  segment, 
and  bring  the  sides  towards  the  median  line. 
Anteriorly  to  these  muscles,  but  further  from 
the  median  line,  is  another  set  of  six  short 
fibres,  the  ubdominales  anteriores  (18),  which 


arise  at  some  distance  from  the  median  line, 
and  passing  transversely  outwards  are  inserted 
into  the  lateral  part  of  the  segment.  The 
abdominales  lateralis  (19)  are  situated  in  the 
posterior  half  of  the  segment.  They  are  in- 
serted by  three  great  fasciculi  of  narrow  ten- 
dons into  the  inner  and  inferior  part  of  the 
segment,  and  consist  of  eight  muscular  fibres 
connected  in  the  first  tendon,  four  in  the  se- 
cond, and  seven  in  the  third.  They  form  very 
powerful  muscles,  which  interlace  with  each 
other,  and  originate  directly  from  the  tegu- 
ment of  the  sides  of  the  segment,  at  different 
distances  posteriorly  to  the  spiracle.  Some  of 
them  (20)  are  much  longer  than  others,  and 
the  whole  of  them  are  connected  with  the  false 
feet  of  the  abdomen.  On  removing  these 
muscles  we  expose  the  attachment  of  the  ob- 
liquus  posterior  (21),  which  is  composed  of 
nine  small  fibres  that  pass  diagonally  outwards 
from  their  origin,  the  anterior  ridge,  to  their 
insertion  in  the  tegument  at  different  distances 
beneath  the  lateral  abdominal  muscles.  Ano- 
ther set  of  nine  distinct  fibres,  the  postero- 
laterals obliqui  (22),  which  originate  from  the 
same  ridge  at  the  lateral  part  of  the  segment, 
cross  over  the  last  lateral  abdominal  muscle, 
and  are  inserted  between  it  and  the  one  im- 
mediately before  it.  Besides  these  layers  of 
fibres  there  are  four  other  sets  which  seem  to 
be  particularly  concerned  in  the  function  of 
respiration.  Of  these  the  transversus  lateralis 
(28)  arises  tendinous  from  beneath  the  lateral 
part  of  the  great  rectus,  and  passing  upwards, 
internal  to  the  great  longitudinal  trachea  (£), 
which  it  crosses,  is  inserted  beneath  the  ex- 
ternal margin  of  the  dorsal  rectus  (A).  The 
second  transversus  lateralis  (24)  arises  pos- 
teriorly to  the  first,  crosses  the  trachea,  and 
continuing  its  course  upwards  is  inserted  into 
the  tegument  of  the  back,  about  half-way 
across  the  dorsal  rectus.  These  muscles  ap- 
pear to  be  directly  concerned  in  contracting 
the  segments  during  expiration.  Besides  these 
muscles  there  are  also  the  retractor  spiraculi 
and  the  retractor  valvule,  which  belong  also  to 
the  ventral  and  lateral  surface  of  each  segment. 
The  retractor  spiraculi  (25)  is  attached  by  a 
long  tendon  (26)  to  the  third  ridge  of  insertion. 
It  is  a  long,  fleshy,  and  somewhat  conical  mus- 
cle, which  passes  upwards  and  obliquely  back- 
wards to  the  spiracle,  unto  the  lower  margin 
of  which  it  is  attached,  and  is  blended  with 
the  circular  fibres  that  constitute  an  orbicular 
muscle  to  that  orifice.  It  appears  to  be  di- 
rectly concerned  in  forcible  expiration,  and 
draws  the  spiracle  inwards  and  downwards, 
and  when  the  orbicular  muscle  acts  in  con- 
junction with  it  assists  in  closing  the  spiracle. 
The  remaining  muscle,  the  retractor  valvulce 
(27),  is  the  direct  antagonist  of  the  last.  It 
is  composed  of  five  distinct  fibres  (fig.  401,  c), 
which  arise  from  the  posterior  margin  of  the 
spiracle,  and  partly  also  from  the  attachment 
of  the  retractor  spiraculi  (e),  and  then,  con- 
verging, end  in  a  tendon  that  passes  diagonally 
upwards  and  backwards,  and  is  inserted  into 
a  little  elevation  in  the  tegument.  It  is  the 
proper  retractor  or  levator  muscle  of  the  spira- 


INSECTA. 


939 


Fig.  401. 


Internal  view  of  spiracle  of  larva  of  Sphinx  ligustri. 
(  Newport,  Phil.  Trans. ) 
a,  anterior  margin  of  spiracle  with  portion  of  the 
trachea;  b,  the  valve;  c,  retractor  valvulae  ;  e, 
retractor  spiraculi  ;  d,  nerve  supplying  these  mus- 
cles. 

cular  orifice,  and  acts  upon  the  internal  valve 
(b),  which  is  situated  a  little  within  the  spiracle. 
This  valve  is  a  thick,  moveable,  dark-coloured 
duplicature  of  the  lining  membrane  of  the 
posterior  border  of  the  spiracle,  and  closes 
on  that  of  the  opposite  side  («),  which  is  a 
concave  crescent-shaped  margin,  not  acted 
upon  by  muscles — like  a  cushion  or  pad. 

These  muscles  of  the  larva  of  the  Sphinx 
differ  but  little  from  those  described  by  Lyonet 
in  the  Cossus.  In  all  insects  they  give  pas- 
sage between  them  to  the  ramifications  of  tra- 
cheal vessels,  which  are  most  extensively  dis- 
tributed throughout  the  whole  body,  to  every 
muscle,  nerve,  or  other  organ.  They  are  also 
covered  in  many  places  by  numerous  con- 
nected vesicles  filled  with  adipose  matter, 
which  exist  in  the  greatest  abundance  in  the 
larva  state  in  all  insects,  occupying  the  inter- 
stices between  the  muscles  and  tracheae.  The 
same  general  structure  of  the  muscular  system 
as  that  which  we  have  just  described  in  the 
Sphinx  exists  in  all  larva?  that  undergo  a  com- 
plete metamorphosis,  whether  they  belong  to 
the  Coleopterous,  Ilymenopterous,  or  Lepi- 
dopterous  classes,  although  in  the  particular 
distribution  and  form  of  the  muscles  in  each 
there  are  necessarily  some  differences  depen- 
dent upon  difference  of  species  and  habit. 
Thus  Burmu.ster  found  a  similar  general  con- 


formation of  parts  in  the  larva  of  Calosoma 
sycophamta*  (jig.  354),  one  of  the  more  per- 
fect Coleoptera,  both  in  the  existence  of  the 
rudiments  of  muscles  for  the  wings  and  in  the 
longitudinal  muscles  of  the  dorsal  and  ventral 
surfaces  of  the  body.  The  muscles  of  the 
larvae  of  Coleoptera,  as  Burmeister  has  re- 
marked, bear  a  greater  resemblance  to  the 
muscles  of  the  perfect  insects  than  those  of  the 
larvae  of  other  classes.  It  is  not  difficult  to 
recognise  in  them  the  same  general  arrange- 
ment of  particular  muscles  which  are  after- 
wards found  in  a  more  or  less  developed  state 
in  the  perfect  insects.  An  admirable  exem- 
plification of  the  muscular  system  of  Coleop- 
tera is  given  by  Straus  Durckheim  in  his 
splendid  work  on  the  anatomy  of  Melolontlia 
vulgaris,  in  which  many  of  the  muscles  that 
exist  in  the  larva  state  may  be  distinctly  iden- 
tified, although  greatly  modified  in  form  and 
size  to  fit  them  for  new  modes  of  action,  which 
have  been  rendered  necessary  by  the  changes 
that  have  taken  place  in  the  habits  and  modes 
of  life  of  the  insect.  Thus,  as  also  remarked 
by  Straus,f  the  great  ventral  series  of  recti 
muscles  which  we  have  just  seen  in  the  larva, 
form  successively  the  retractor  muscles  of  the 
labium,  the  depressors  of  the  head,  the  re- 
tractors or  depressors  of  the  pro-sternum,  or 
those  which  draw  that  part  to  the  meso-sternum, 
and  the  pretractors  of  the  post-furca  or  trian- 
gular process  of  the  metasternum ;  and,  lastly, 
the  inferior  recti  muscles  of  the  abdomen.  But 
in  each  of  these  instances  the  size  and  form  of 
the  muscles  are  greatly  altered,  more  especially 
in  the  thoracic  region,  while  in  the  abdominal 
region  those  of  the  posterior  segments  exist 
with  less  change  of  form  than  in  the  thoracic, 
but  are  greatly  reduced  in  size,  and  those  of 
the  anterior  abdominal  segments,  in  which  the 
ventral  plates  of  two  or  more  segments  have 
become  consolidated  together,  are  atrophied 
and  have  almost  disappeared.  In  like  manner 
the  dorsal  recti  of  the  larva  exist  in  the  imago 
in  the  new  form  of  elevators  of  the  head, 
superior  retractors  or  elevators  of  the  prothorax 
and  scutellum,  and  levators,  depressors,  and 
adductors  of  the  wings  and  dorsal  longitudinal 
recti  of  the  abdomen.  In  the  latter  region 
neither  their  form  nor  direction  have  been 
changed,  but  like  the  ventral  recti  they  have 
been  mucli  reduced  in  size,  because  there  is  less 
necessity  for  their  active  employment  in  the 
perfect  than  in  the  larva  state,  in  which  nearly 
the  whole  of  the  locomotive  powers  of  the  in- 
dividual are  entirely  dependent  upon  those 
muscles.  Their  form  and  direction  have  not 
been  changed  because  the  direction  in  which 
they  ar«  employed  in  the  perfect  state  is  pre- 
cisely similar  to  that  in  which  they  are  em- 
ployed in  the  larva.  But  this  is  not  the  case 
in  the  thoracic  region,  in  which  not  only  have 
they  been  enormously  increased  in  size  and 
changed  in  form,  but  their  relative  position 
has  also  been  altered,  owing  to  the  changes 
that  have  taken  place  during  the  metamor- 

*  Trans.  Entom,  Society,  Lend.  vol.  i.  |).  335. 
t  Considerat  Geiicrales,  p.  14SJ. 


940 


INSECTA. 


phoses  in  the  position  of  parts  of  the  tegu- 
mentary  skeleton,  to  which  the  muscles  aie 
attached.  Hence  the  direction  in  which  thtse 
muscles  are  now  required  to  act  is  also  cl  anged, 
and  from  constituting,  as  in  the  larv;t,  01  ly 
one  continuous  series  of  uniform  mmcles, 
acting  in  one  direction,  in  the  perfect  insect 
they  become  muscles  that  act  in  several  direc- 
tions, at  different  angles  of  the  body,  and  in 
some  parts  exceed  in  importance  and  size 
every  other  division  of  the  muscular  system. 
Thus,  in  the  thoracic  region,  the  dorsal  mus- 
cles, which  were  parts  least  employed  in  the 
larva,  are  those  which  are  of  the  greatest  im- 
portance in  the  perfect  insect,  both  as  regards 
size  and  function.  In  the  larva,  as  we  have 
seen,  locomotion  depends  chiefly  upon  the  ab- 
dominal recti ;  but  in  the  perfect  insect,  on  the 
contrary,  nearly  the  whole  of  this  power  is 
transferred  to  the  dorsal  muscles  of  the  thorax. 
Hence  the  arrangement  of  these  muscles  is 
more  or  less  intricate,  and  differs  in  different 
classes,  according  to  the  habits  of  the  insects. 
Thus,  in  those  classes  in  which  the  prothorax 
is  short,  and  almost  or  entirely  anchylosed  to 
the  meso-thorax,  as  in  the  Hymenoptera,  Lepi- 
doptera,  and  Diptera,  and  in  which,  conse- 
quently, scarcely  any  motion  of  the  prothoracic 
segment  is  required,  the  muscles  become  al- 
most entiiely  atrophied  and  cease  to  exist,  or, 
as  is  sometimes  the  case,  their  attachments  are 
transferred  to  a  different  part  of  the  tegumen- 
tary  skeleton. 

The  most  generally  developed  form  of  the 
muscular  system  of  the  thorax  is  found  in  the 
Coleoptera,  of  which  Straus  has  given  so  admira- 
ble an  illustration  in  his  anatomy  of  Melolontha. 
It  is  from  his  description  of  the  muscles  of  that 
insect  that  we  shall  chiefly  derive  our  general 
description  of  these  parts  in  perfect  insects. 
We  shall,  however,  for  the  sake  of  uniformity, 
adopt  the  nomenclature  applied  to  these  parts 
by  liurmeister,  identifying  it  with  the  names 
originally  employed  by  Straus. 

The  muscles  that  connect  the  head  with  the 
thorax  are  contained  within  the  prothorax  (fig. 
402,2),  and  are  of  three  kinds,  extensors,Jlexors, 
and  retractors.  The  extensors,  levatures  capitis 
(a,  a),  consist  of  two  pairs,  one  of  which  arises 
from  the  middle  line  of  the  pronotum,  and 
diverging  laterally  from  its  fellow  of  the  oppo- 
site side,  passes  directly  forwards  and  is  in- 
serted by  a  narrow  tendon  into  the  anterior 
superior  margin  of  the  occipital  foramen.  The 
other  arises  further  back  from  the  prophragma. 
It  is  a  long  narrow  muscle  that  passes  directly 
forwards  through  the  prothorax,  and  is  inserted 
by  a  tendon  near  the  superior  median  line  of 
the  foramen ;  so  that  while  this  muscle  and  its 
fellow  of  the  opposite  side  elevate  the  head 
almost  in  a  straight  line,  the  one  first  described, 
when  acting  alone  or  singly,  draws  the  head  a 
little  on  one  side ;  but  when  the  whole  of  these 
muscles  act  in  unison,  they  simply  elevate  the 
head  upon  the  prothorax.  The  depressors  or 
flexors,  depressores  capitis  (b),  are  exceedingly 
short  muscles,  which  arise  from  the  jugular 
plate,  or,  when  that  part  does  not  exist,  from 
the  border  of  the  pro-sternum,  and  are  attached 


Fig.  402. 


Section  of  the  body  of  Melolontha.    ( Straus.) 


to  the  inferior  margin  of  the  occipital  foramen. 
They  simply  flex  the  head  on  the  prothorax.  The 
lateral  flexors,  depressores  externi  id),  are  two 
little  muscles  that  arise  from  the  same  point  as 
the  preceding,  and  are  attached  to  the  lateral 
inferior  margin  of  the  occipital  foramen.  The 
rotatory  muscles,  rutatures  capitis  (c),  are  two 
flat  muscles  like  the  elevators,  which  arise,  one 
at  the  side  of  the  ante-furca  and  the  other  from 
the  posterior  jugular  plate,  and  passing  up- 
wards and  outwards  are  attached  to  the  lateral 
margin  of  the  occipital  foramen.  The  retractor 
or  flexor  of  the  jugular  plate  is  a  small  muscle 
(e)  that  arises  from  the  margin  of  the  ante-furca, 
and  passing  directly  forwards  is  inserted  by  a 
small  tendon  into  the  middle  of  the  jugular 
piece.  The  oblique  extensor  of  the  jugular 
plate  is  a  long  slender  muscle  (/)  that  arises 
from  the  external  margin  of  the  pronotum,  and 
passing  obliquely  downwards  and  forwards 
traverses  the  prothorax  and  is  inserted  by  a 
narrow  tendon  to  the  jugular  plate  immediately 


INSECTA. 


941 


before  the  retractor.  The  other  retractor  (g) 
arises  from  the  anterior  superior  boundary  of 
the  pronotum,  and  passing  downwards  is  in- 
serted into  the  jugular  plate  between  the  larger 
levator  and  the  flexor  capitis. 

The  muscles  proper  to  the  prothorax  consist 
of  four  pairs,  by  which  it  is  united  to  the  suc- 
ceeding segments.     The  first  of  these,  the 
superior  retractor,  retractor  prothoracis  superior 
(/i),  arises  by  a  broad  fleshy  head  from  the 
anterior  external  margin  of  the  pronotum,  and 
passing  directly  backwards  is  inserted  by  a 
tendon  into  the  prophragma  a  little  on  one  side 
of  the  median  line.    The  next  muscle  of  im- 
portance, the  i)vferiorretrdctor{i), arises  from  the 
anterior  border  of  the  medi-furca,  and  is  united 
to  the  posterior  of  the  ante-furca,  thus  forming 
with  that  muscle  part  of  the  great  recti  of  the 
larva.    This  muscle  must  be  considered  as  the 
proper  depressor  of  the  prothorax.    The  eleva- 
tor prothoracis  (k)  is  narrow,  pyramidal,  and 
arises  fleshy  from  the  lateral  surface  of  the 
prophragma.     It   passes  downwards  and  is 
attached  by  a  narrow  tendon  to  the  superior 
portion  of  the  ante-furca.    The  rotatores  pro- 
thoracis are  the  largest  of  all  the  muscles  of 
this  segment.  They  arise,  one  on  each  side  (/), 
by  a  narrow  head  from  the  posterior  part  of 
the  pronotum,  and  passing  beneath  the  pro- 
phragma are  considerably  enlarged  and  attached 
to  the  tegument  between  the  two  segments, 
and  also  to  the  anterior  portion  of  the  meso- 
thorax.    The  remaining  muscle  proper  to  the 
prothorax  is  the  closer  of  the  spiracle,  an  ex- 
ceedingly small  muscle  not  shewn  in  the  draw- 
ing.   The  other  muscles  of  this  segment  are 
those  of  the  legs,  which  are  of  considerable 
size.    There  are  three  distinct  flexors  of  the 
coxa  (in,  n,  o).    The  first  of  these  arises  from 
the  superior  lateral  border  of  the  pronotum, 
the  second  from  the  superior  posterior  border, 
the  third  from  the  sides  of  the  prothorax,  and  the 
fourth  a  little  nearer  posteriorly,  and  the  whole 
of  them  are  attached  by  narrow  tendons  to  the 
sides  of  the  coxa.     But  there  is  only  one 
extensor  muscle  to  this  part.    In  like  manner 
the  extensor  of  the  trochanter  is  foimed  of 
three  portions,  (Jig-  403,  a,  b,  c,)  but  there  is 
only  one  flexor  (d)  and  one  abductor  (e). 
In  the  femur  there  is  one  extensor  (/'),  a  long 
penniform  muscle  that  occupies  the  superior 
part  of  the  thigh,  and  is  attached  by  a  tendon 
to  the  anterior  posterior  margin  of  the  joint, 
formed  by  the  end  of  the  tibia.    There  is  also 
but  one  flexor  (g)  in  the  femur,  which,  like  the 
preceding  muscle,  is  penniform,  and  occupies 
the   inferior  portion   of  the  femur,   and  its 
tendon  is  attached  to  the  inferior  border  of  the 
tibia.    In  the  tibia  itself  there  is  also  one 
flexor  and  one  extensor.  The  flexor  (i)  occupies 
the  superior  portion  of  the  limb,  and  ends  in 
a  long  tendon  (/)  that  passes  directly  through 
the  joints  of  the  tarsus  on  their  inferior  surface, 
and  is  attached  to  the  inferior  margin  of  the 
claw  (g).    The  extensor  (/;)  occupies  the  infe- 
rior portion  of  the  tibia  and  is  shorter  than  the 
preceding  muscle,  like  which  it  ends  in  a  long 
tendon  that  is  attached  to  the  upper  margin  of 
the  claw.    Besides  these  muscles,  which  are 


Fig.  403. 


Muscles  of  the  anterior  leg  of  Melolontha  vulgaris. 
(  Straus.  J 


common  to  the  joints  of  the  tarsus,  there  are 
two  others  belonging  to  the  claw,  situated  in 
the  last  joint.  The  first  of  these,  the  extensor 
(in),  is  short  and  occupies  the  superior  portion 
of  the  last  phalanx  of  the  tarsus,  and  the  other, 
the  flexor  (n),  is  a  much  longer  penniform 
muscle,  which  occupies  nearly  the  whole  of 
the  upper  and  under  surface  of  the  posterior 
part  of  the  phalanx,  and  is  attached,  like  the 
long  flexor  of  the  tarsus,  to  the  inferior  part  of 
the  claw.  These  are  the  muscles  of  the  pro- 
thorax and  its  organs  of  locomotion,  as  shewn 
by  Straus,  and  exemplify  the  extent  unto  which 
the  muscular  system  is  developed  in  perfect 
insects.  The  muscles  of  the  other  segments  of 
the  thorax  differ  considerably  from  these  in 
their  form  and  arrangement,  but  the  length 
unto  which  this  article  has  already  been  carried 
prevents  us  from  entering  particularly  into  their 
consideration.  The  great  depressor  muscle  of  the 
wings,  musculus  mctanoti  (fig.  402,  x),  occupies 
with  its  fellow  the  chief  portion  of  the  dorsal 
surface  of  the  meso-  and  meta-thorax,  and  the 
elevators  and  pretractors,  musculi  laterules  me- 
tanoti  (j/,?/),  the  lateral  superior  parts  of  the 
same  segment,  and  descending  obliquely  back- 
wards are  attached  to  the  metaphragma  and 
base  of  the  post-furca.  The  other  muscles 
which  belong  to  the  legs  and  those  that  connect 
the  thorax  to  the  abdomen  are  of  considerable 
size.  One  of  those  of  the  posterior  legs,  the 
second  flexor  (z),  is  seen  immediately  behind 
the  muscles  of  the  wings,  and  the  extensors 
(a,  a)  at  the  posterior  part  of  the  segment.  In 
the  abdomen  the  chief  muscles  are  the  dorsal 


942 


INSECTA. 


recti  (c,  c)  on  the  upper  svirface,  and  the  corres- 
ponding ones  on  the  ventral,  which  are  now 
chiefly  subservient  to  the  motions  of  the  organs 
of  generation. 

From  the  number  and  complexity  of  the 
muscles  in  these  "  miniatures  of  creation"' — 
insects- — we  feel  less  surprised  at  the  agility  of 
their  movements  and  the  variety  of  motions 
which  many  of  them  perform,  and  less  asto- 
nishment at  the  wonderful  strength  which 
many  species  possess.  But  still  there  are 
instances  of  some  of  them  possessing  a  degree 
of  power  that  is  almost  incredible.  The  great 
stag-beetle,  Lucunus  cervus,  which  tears  off 
the  bark  from  the  roots  and  branches  of  trees, 
has  even  been  known  to  gnaw  a  hole  an  inch  in 
diameter  through  the  side  of  an  iron  canister  in 
which  it  was  confined,  and  on  which  the  traces 
of  its  mandible  were  distinctly  visible,  as  proved 
by  Mr.  Stephens,  who  exhibited  the  canister  at 
one  of  the  meetings  of  the  Entomological  So- 
ciety,"* an  indication  of  an  amount  of  strength 
possessed  by  these  insects  of  which  before  we 
could  have  had  no  conception.  But  hardly 
Jess  surprising  is  the  strength  possessed  by 
Geotrupes  stercorarius,  which  can  support  un- 
injured, and  even  elevate  an  immense  weight, 
and  make  its  way  beneath  almost  any  amount 
of  pressure.  In  order  to  ascertain  the  amount 
of  strength  possessed  by  this  insect,  we  have 
made  a  few  experiments  from  which  it  appears 
that  it  is  able  to  sustain  and  escape  from 
beneath  a  pressure  of  from  twenty  to  thirty 
ounces,  a  prodigious  weight  when  it  is  remem- 
bered that  the  insect  itself  does  not  weigh  even 
so  many  grains.  But  this  amount  of  strength 
is  not  confined  to  the  short  thick-limbed  beetles. 

We  once  fastened  a  small  Carabus  (  ?), 

weighing  only  three  grams  and  a  half,  by  means 
of  a  silken  thread  to  a  small  piece  of  paper, 
upon  which  the  weight  to  be  moved  was  placed. 
At  a  distance  of  ten  inches  from  its  load  the 
insect  was  able  to  drag  after  it,  up  an  inclined 
plane  of  twenty-five  degrees,  very  nearly  eighty- 
five  grains.  But  when  placed  on  a  plane  of 
five  degrees  it  drew  after  it  one  hundred  and 
twenty-five  grains  exclusive  of  the  friction  to 
be  overcome  in  moving  its  load. 

The  motions  of  the  insect  in  walking  as  in 
fiying  are  dependenl  in  the  perfect  individual 
entirely  upon  the  thoracic  segments,  but  in  the 
larva  chiefly  upon  the  abdominal.  Although 
the  number  of  legs  in  the  former  is  always  six, 
and  in  the  latter  sometimes  so  many  as  twenty- 
two,  progression  is  simple  and  easy.  Midler 
states  f  that  on  watching  insects  that  move 
slowly  he  has  distinctly  perceived  that  three  legs 
are  always  moved  at  one  time,  being  advanced 
and  put  to  the  ground  while  the  other  three 
propel  the  body  forwards.  In  perfect  insects 
those  moved  simultaneously  are  the  fore  and 
hind  feet  on  one  side  and  the  intermediate  foot 
on  the  opposite,  and  afterwards  the  fore  and 
hind  feet  on  that  side  and  the  middle  one  on 
the  other,  so  that,  he  remarks,  in  two  steps  the 

*  Transact.  Ent.  Soc.  Lond.,  vol.  ii.  Journal  of 
Proceedings,  p.  xxii. 
i  Elements  of  Physiology,  p.  970.  (Transl.) 


whole  of  the  legs  are  in  motion.  A  similar 
uniformity  of  motion  takes  place  in  the  larva, 
although  the  whole  anterior  part  of  the  body  is 
elevated  and  carried  forwards  at  regular  dis- 
tances, the  steps  of  the  insect  being  almost 
entirely  performed  by  the  false  or  abdominal 
legs. 

In  fligh  t  the  motions  depend  upon  the  meso- 
and  meta-thoracic  segments  conjointly,  or  en- 
tirely upon  the  former.  The  sternal,  episternal, 
and  epimeral  pieces,  freely  articulated  together, 
correspond  in  function  with  the  sternum,  the 
ribs,  and  the  clavicles  of  birds.*  The  thorax 
is  expanded  and  contracted  at  each  motion  of 
the  wings,  as  in  birds  and  other  animals,  and 
becomes  fixed  at  each  increased  effort  as  a 
fulcrum  or  point  of  resistance  upon  which  the 
great  muscles  of  the  wings  are  to  act,  thus 
identifying  this  part  of  the  body  in  function  as 
in  structure  with  that  of  other  animals. 

The  Nervous  System. — Comparative  exami- 
nations of  the  nervous  system  in  Articulata, 
and  the  changes  which  it  undergoes,  more  es- 
pecially in  Insects,  as  well  as  the  existence  in 
it  of  parts  which  we  regard  as  analogous  to  the 
motor  and  sensitive  portions  of  the  spinal  cord 
in  vertebrata,  have  invested  this  division  of  our 
subject  with  more  than  a  common  amount  of 
interest. 

It  has  been  shewn  in  a  former  part  of  this 
work,f  that  in  Articulata  the  most  rudimentary 
condition  of  the  nervous  system  exists  in  the 
form  of  two  longitudinal  cords,  extended  along 
the  median  line  of  the  under  surface  of  the 
body,  parallel  with  each  other,  and  nearly  close 
together,  excepting  at  their  anterior  part,  where 
they  diverge,  and  pass  upwards,  to  embrace  be- 
tween them  the  commencement  of  the  alimen- 
tary canal.  In  a  more  advanced  stage  of  or- 
ganization each  of  these  cords  has  a  series  of 
enlargements  or  ganglia  in  its  course,  situated 
at  certain  distances  apart,  and  varying  in  num- 
ber according  to  the  number  of  segments  into 
which  the  body  of  the  animal  is  divided. 
These  enlargements  correspond  precisely  in  si- 
tuation in  both  cords,  so  that  the  nervous  sys- 
tem in  this  condition  may  be  described  simply 
as  composed  of  two  knotted,  parallel  cords. 
The  enlargements  in  one  cord  are  either  placed 
close  to  the  corresponding  ones  in  the  other,  or 
are  separated  only  by  a  very  slight  interspace. 
This  is  the  form  in  which  the  nervous  system 
exists,  as  we  have  seen,  in  the  Talitrus,J  in 
which  the  ganglia  are  approximated  together, 
but  are  still  distinct  from  each  other,  and  form 
a  double  series  of  enlargements,  united  by  in- 
tervening cords.  This  is  also  the  condition  in 
which  the  nervous  system  exists  in  its  most  ru- 
dimentary state  in  the  larva  of  hexapodous 
insects.  But  these  parallel  cords,  which  toge- 
ther form  the  analogue  of  the  cerebro-spinal 
system  of  vertebrata,  and  correspond  one  to 
each  side  of  the  body,  are  not  in  themselves 
simple  structures,  each  one  being  composed  of 

*  Bennet  on  the  anatomy  of  the  thorax  in  insects, 
and  its  function  during  flight,  Zoological  Journal, 
vol.  i.  p.  394. 

t  Art.  Crustacea,  Entozoa,  Annelida. 

t  Crustacea,  vol  i.  p.  763,  fig.  391. 


INSECTA. 


943 


two  distinct  columns  of  fibres,  placed  one  upon 
the  other,  and  closely  united  together  in  every 
instance.  The  under  or  external  column, 
which  is  nearest  to  the  exterior  of  the  body,  is 
that  in  which  the  ganglia  or  enlargements  are 
situated.  The  upper  one,  or  that  which  is 
internal  and  nearest  to  the  viscera,  is  entirely 
without  ganglia,  and  passes  directly  over  the 
ganglia  of  the  under  column  without  forming 
part  of  them,  but  in  very  close  approximation 
to  them.  In  some  species,  as  in  the  larvae  of 
Timarcha  tenebricosa,  (fig-  404,  2,  3,  4,)  and 
Proscalabams  vulgaris,  among  the  Coleoptera, 
and  of  the  Bee  and  other  Aculeate  Hymenop- 
tera,  this  column  is  more  apparent  than  in  the 
larvae  of  Lepidoptera,  in  which  it  is  indistinctly 
seen,  excepting  when  it  is  beginning  to  pass 
over  or  is  just  leaving  the  surface  of  a  ganglion. 

Fig.  404. 


A. 


Nervous  system  of  the  larva  of  Timarcha  teneltricosa. 
ii,  natural  size. 

The  ganglionics?  upper  or  internal  column 
of  fibres  is  the  part  which  we  believe  to 


be  analogous  to  the  motor  column  of  verte- 
brata,  and  the  external  or  under  one,  in  which 
the  ganglia  are  situated,  we  regard  as  the  ana- 
logue of  the  sensitive.  Thus  the  two  cords  are 
each  composed  of  a  motor  and  a  sensitive  co- 
lumn, and  represent,  we  believe,  the  cerebro- 
spinal system  of  vertebrate.  In  the  Aculeate 
Ilymenoptera,  the  ganglia  of  the  cords  are  in  a 
state  of  development  similar  to  those  of  the 
Talitrus  ;  they  are  approximated  together  late- 
rally, but  still  remain  distinct  from  each  other, 
and  thus  present  a  transitory  condition  in  the 
larva  state  of  an  insect  similar  to  their  perma- 
nent one  in  the  lower  Crustacea.  In  the  Timar- 
cha, the  anterior  pair,  or  supra-casophageal  gang- 
lia, still  continue  distinct  from  each  other,  (fig. 
405,  A  A,)  and  retain  their  rudimentary  form, 
as  in  the  Talitrus,  and  the  cords  are  also  sepa- 
rated ;  but  the  several  pairs  of  subcesophageal 
ganglia  have  each  coalesced  into  a  single  mass. 

Fig.  405. 


A  A 


The  supra-aesophageal  ganglia,  or  brain  of  larva  of 
Timarcha  tenebricosa.    (  Newport,  Phil.  Trans.) 

A  similar  coalescence  of  the  ganglia,  but  car- 
ried to  a  less  extent,  exists  in  the  larvae 
of  Lepidoptera,  in  which  the  form  of  the  ner- 
vous system  of  insects  has  been  most  frequently 
examined.  Malpighi  and  Swammerdam  ex- 
amined this  structure  in  the  Silkworm,  and 
Lyonet  in  the  larva  of  the  Goat-moth,  Cossus 
ligniperda.  We  have  also  examined  it  in  the 
larva  of  the  Privet  Hawk-moth,  Sphinx 
ligustri,  in  which  we  shall  now  describe  its 
general  form  and  distribution. 

Curd  and  nerves  of  the  larva. — In  the 
larva  of  the  Sphinx,  ( fig.  406,)  as  in 
most  others  of  the  vermiform  type,  the  nor- 
mal number  of  double  ganglia  is  thirteen. 
The  anterior  pair  (A)  situated  above  the  oeso- 
phagus, represent  the  brain,  and  the  first  of 
those  which  are  situated  below  it,  (/»,)  the 
medulla  oblongata.  These  are  the  proper 
ganglia  of  the  head  or  first  segment,  and  the 
cords  by  which  they  are  connected  together, 
and  which  descend  one  on  each  side  of  the 
oesophagus,  in  like  manner  represent  the  crura. 
Posteriorly  to  the  medulla  oblongata,  which  we 
shall  distinguish  as  the  first  subcesophageal 
ganglion,  the  cords  pass  directly  backwards  into 
the  second  segment,  where  they  form  the  se- 
cond subcesophageal  ganglion  (2).    They  then 


944 


INSECTA. 


diverge  a  little  from  each  other,  and  include 
between  them  the  insertions  of  the  first  set  of 
diagonal  muscles,  and  at  the  posterior  part 
of  the  third  segment  again  approach  each 
other,   and   form    the    third    ganglion  (3). 

Fig.  406. 


A. 


Nervous  system  of  the  larva  o  f  Sphinx  ligtistri. 
(Newport,  Phil.  Trans.) 

They  then  again  diverge,  and  continuing  their 
course  into  the  next  segment,  pass  on  each  side 
of  the  insertion  of  a  second  set  of  muscles,  and 
approaching  at  the  hinder  part  of  the  fourth 


segment  form  the  fourth  ganglion,  (4,)  from 
which  they  continue  their  course  side  by  side, 
and  in  the  next  segment  form  the  fifth  and  last 
ganglion,  (5,)  that  enters  into  the  composition 
of  the  thoracic  portion  of  the  nervous  cord  in 
the  perfect  insect.  From  the  fifth  ganglion  the 
cords  are  continued  in  a  direct  line,  into  the 
sixth,  seventh,  and  succeeding  segments,  form- 
ing in  each  a  double  ganglion,  to  the  eleventh, 
where  they  form  the  terminal  ganglion  (11,12). 
This  is  considerably  larger  than  any  of  the  pre- 
ceding, being  in  reality  composed  of  two  dis- 
tinct pairs,  which  originally  were  separated 
from  each  other  by  intervening  cords,  and  be- 
longed to  the  eleventh  and  twelfth  segments, 
but  which  seem  to  approach  and  become  closely 
approximated  to  each  other  during  the  earlier 
period  of  the  larva  state,  as  suggested  by  Dr. 
Grant,  and  supported  by  the  fact  that  these 
ganglia  are  found  more  or  less  approximated 
together  in  different  individuals,  the  terminal 
ganglion  in  some  being  distinctly  formed  of  two 
pairs,  scarcely  united,  and  in  others  so  com- 
pletely coalesced  as  hardly  to  be  distinguished. 
In  other  Lepidoptera,  as  in  Odonestis  potatoria 
and  Lusiocampu  neustria,  and  as  represented 
also  by  Lyonet,  in  Cossus  ligniperdu,*  the 
ganglia  continue  distinct,  and  are  separated  by 
a  very  short  portion  of  the  cords.  ■  But  in  the 
Timarcha,  the  eleventh  and  twelfth  ganglia 
have  completely  coalesced,  and  it  is  remark- 
able that  they  are  also  united  even  in  the 
rudimentary  form  of  the  nervous  system  in  the 
aculeate  Hymenoptera,  as  in  the  larva  of  the 
bee,  and  even  in  its  still  more  rudimentary  state 
in  the  larva  of  Ichneumon  Atropos,  in  both 
which  there  are  originally  thirteen  distinct  pairs 
of  ganglia,  including  the  supra-cesophageal  ones, 
although  Burmeister  has  imagined  that  the 
apodal  larvae  of  Hymenoptera  have  a  nervous 
system  without  ganglia,f  similar  to  what  he  has 
observed  and  figured  in  the  larvae  of  some  Dip- 
tera.  It  was  shown  by  Swammerdam,  J  that  in 
the  Lamellicornes,  as  in  Oryctes  nasicurnis, 
the  cords  are  united  laterally,  and  do  not  extend 
beyond  the  fourth  segment,  from  whence  the 
nerves  radiate  into  the  abdomen.  In  Dyticus, 
according  to  Burmeister, §  the  two  approxi- 
mated cords  are  very  short,  and  the  pairs  of 
ganglia  are  contiguous  to  each  other,  and  he 
has  found  a  similar  form  of  the  nervous  system 
in  the  Hog-beetles,  Calandru  sommeri,  in  which 
there  are  twelve  pairs  of  closely  approximated 
subcesophageal  ganglia.  The  supra-cesophageal 
pair  in  this  species  are  distinct,  as  in  Timarcha, 
but  each  pair  of  the  subcesophageal  has  co- 
alesced into  a  single  mass,  as  in  that  insect,  and 
the  whole  do  not  extend  beyond  the  fifth  seg- 
ment, from  whence  the  nerves  radiate  into  the 
abdomen,  as  in  the  Lamellicornes.  These  are 
the  conditions  which  the  double  cord  presents 
in  the  different  classes.  In  describing  the 
nerves  that  proceed  from  it,  we  shall  divide  them 
into  those  of  the  head,  the  thorax,  the  abdomen, 
and  the  organic  functions. 

*  Plate  ix. 

t  Manual,  (translat.)  p.  279. 

\  Biblia  "Natura,  Tab.  xxviii.  fig.  1. 

\  Op.  cit. 


INSECTA. 


945 


Nerves  of  the  head. — When  the  first  pair  of 
ganglia,  which  always  constitute  the  brain,  are 
viewed  from  above,  they  each  present  a  convex 
uniform  appearance,  arid  are  distinguished 
from  each  other  by  a  depression  between  them, 
which  is  more  apparent  on  their  anterior  than 
their  posterior  surface,  and  is  occasioned  by  the 
lateral  part  of  each  lobe  or  ganglion  being  car- 
ried a  little  forwards,  so  that  the  two  lie  across 
the  oesophagus  in  a  curved  or  lunated  direction. 
On  their  under  surface  they  are  concave,  to 
adapt  them  to  the  form  of  the  oesophagus, 
above  which  they  are  situated.  From  the  an- 
terior and  lower  part  of  each  lobe  originate 
four  remarkable  nerves,  which  belong  to  the 
organs  of  sense  and  the  viscera.  The  first  and 
largest  of  these,  the  optic,  passes  a  little  for- 
wards and  outwards  to  the  stemmata,  a  little 
behind  the  mandibles;  the  second,  the  anten- 
rtal,  passes  a  little  more  anteriorly,  to  the  pajpi- 
form  antenna;  the  third,  and  most  inferior, 
descends  at  the  side  of  the  pharynx,  and  uniting 
with  its  fellow  of  the  opposite  side  forms  a 
loop  or  collar  around  the  oesophagus,  to  the 
under-surface  of  which  it  distributes  a  few  fila- 
ments. We  consider  it  as  analogous  to  the 
glossopharyngeal  nerve  of  vertebrata.  The 
fourth  is  situated  between  the  second  and  third. 
It  passes  a  little  forwards  from  its  origin,  and 
then  ascending  above  the  pharynx,  meets  its 
fellow  of  the  opposite  side,  with  which  it  forms 
a  minute  ganglion,  from  the  hinder  part  of 
which  a  single  nerve  passes  backwards  (b) 
beneath  the  brain,  in  the  median  line  above  the 
oesophagus,  to  the  stomach  and  viscera.  This 
nerve  was  discovered  by  Swammerdam,*'  who 
called  it  the  recurrent,  from  the  manner  in 
which  it  originates  and  is  distributed,  and  it 
was  afterwards  minutely  figured  and  described 
by  Lyonet.  Miiller  has  since  described  it 
minutely,  and  figured  it  in  many  species,  in  his 
paper  on  the  sympathetic  nerves  of  insects,  as 
the  proper  visceral  nerve,  analogous  to  the  sym- 
pathetic. In  a  paper  in  the  Philosophical 
Transactions  in  1832,  we  described  it  as  the 
vagus,\  of  which  we  believe  it  is  the  proper 
analogue.  At  that  time  we  were  led  to  sup- 
pose that  it  had  previously  been  so  described 
by  Straus  Durckheim,  but  such,  as  we  have 
since  found,  was  not  the  case.  We  shall  pre- 
sently return  to  our  description  of  this  nerve, 
in  the  perfect  insect,  as  belonging  to  those  of 
the  organic  functions.  Besides  these  four  pairs 
of  nerves  from  the  anterior  part  of  the 
brain,  there  is  also  one  minute  pair  from  the 
posterior,  which  is  directed  backwards,  and  de- 
veloped on  each  side  of  the  head  into  two  pairs 
of  little  ganglia,  («,)  which  constitute  part  of 
the  sympathetic  system.  The  first  of  these 
ganglia  was  discovered  and  rudely  figured  by 
Swammerdam,};  and  afterwards  more  correctly 
by  Lyonet,  and  the  second  by  Straus  Durck- 
heim. We  have  designated  them  from  their 
situation  the  anterior  lateral  ganglia.^ 

*  Op.  cit.  tab.  xxviii.  fig  2. 

t  Part  2,  p.  386. 

X  Op.  cit.  tab.  xxviii.  tig.  3  i. 

$  Philosophical  Trans,  p.  2,  1832,  page  387. 

VOL.  II. 


These  are  the  proper  cerebral  nerves  of  the 
larva,  and  belong  to  the  senses  and  organic  func- 
tions. The  medulla  oblongata,  or  first  subceso- 
phageal  ganglion,  also  gives  origin  to  four  pairs 
of  nerves.  The  most  anterior  pair  of  these  is 
given  to  the  labium  ;  the  next  to  the  palpif'orm 
maxillae;  the  third,  the  analogue  of  the  fifth  of 
vertebrata,  conjointly  to  the  muscles  of  the 
mandibles  and  maxillae ;  and  the  fourth,  the 
most  posterior  pair,  to  the  silk  vessels,  the  pro- 
per salivary  organs  of  the  larva. 

The  nerves  of  the  thorax  belong  to  the  se- 
cond, third,  fourth,  and  fifth  suboesophageal 
ganglia,  and  their  intervening  cords.  The  first 
pair  of  nerves  from  the  second  ganglion  (2) 
are  exceedingly  small,  and  are  given  to  the 
retractor  muscles  of  the  head.  The  second 
pair  (c)  are  large,  and  are  divided  into  many 
branches  that  are  given  to  the  whole  of  the 
muscles  of  the  lateral  and  superior  part  of  that 
segment,  and  the  third  (d)  are  directed  back- 
wards, and  supply  the  anterior  or  prothoracic 
legs.  The  third  ganglion  (3)  produces  also 
three  pairs  of  nerves.  About  midway  between 
the  second  and  third  ganglion  the  cord  pro- 
duces on  each  side  a  single  nervous  trunk  (f), 
which  is  directed  a  little  backwards,  and  unites 
at  an  angle  with  the  first  nerve  from  the  third 
ganglion.  These  together  from  a  single  trunk, 
which  in  the  early  stage  of  the  larva  is  exceed- 
ingly small,  but  increases  much  in  size  as  the 
period  of  changing  into  the  pupa  state  ap- 
proaches. It  is  the  first  alary  nerve,  and  is 
given  to  the  future  anterior  pair  of  wings,  and 
is  now  distributed  among  the  muscles  of  the 
anterior  part  of  the  segment.  It  is  also  con- 
nected with  one  set  of  the  transverse  nerves  (e), 
which  exist  in  each  segment  loosely  attached 
to  the  cords,  and  which  we  shall  describe  more 
particularly  hereafter.  The  second  pair  of 
nerves  from  this  ganglion  produce  each  at  their 
base  a  small  branch,  which  has  the  appearance 
of  a  distinct  nerve,  and  which  is  distributed 
laterally  to  the  deep-seated  muscles,  while  its 
main  trunk  (g)  is  given  to  the  second,  or  meso- 
thoracic  pair  of  legs.  Half-way  between  the 
third  and  fourth  ganglion  the  cord  again  pro- 
duces on  each  side  a  single  nervous  trunk  (i), 
which,  like  the  corresponding  one  in  the  pre- 
ceding segment,  is  directed  backwards,  and 
unites  with  the  first  nerve  from  the  third  gan- 
glion. It  is  the  second  alary  nerve  given  to 
the  muscles  of  the  future  second  pair  of  wings. 
Like  the  corresponding  nerve  in  the  preced- 
ing segment,  it  is  very  small  during  the  early 
period  of  the  larva  state,  but  is  greatly  en- 
larged as  the  period  of  transformation  ap- 
proaches. It  also  unites,  like  the  former,  with 
a  set  of  the  transverse  nerves  (A),  and  then 
passes  outwards  about  midway  across  the  recti 
muscles,  between  which  it  penetrates,  and 
pursues  its  course  upwards  to  the  lateral  and 
dorsal  muscles  of  the  segments,  and  which  are 
to  act  upon  the  future  wings.  The  second 
nerve  from  the  ganglion  divides,  like  the  cor- 
responding one  from  the  ganglion  of  the  pre- 
ceding segment,  into  two  branches,  one  of 
which  (/c)  crosses  the  smaller  rectus  muscle, 
and  passes  beneath  the  larger  to  the  dorsal 

3  Q 


946 


INSECTA. 


muscles  of  this  segment,  and  the  second  is 
given  directly  to  the  third  pair  of  legs.  The 
fifth  ganglion  (5),  which  is  situated  at  the  an- 
terior part  of  the  fifth,  or  thoracico-abdominal 
segment,  belongs,  as  we  shall  hereafter  see,  to 
the  thorax.  Like  the  abdominal  ganglia  it 
gives  off  two  distinct  pairs  of  nerves,  the  an- 
terior of  which  crosses  the  smaller,  and  de- 
scends beneath  the  larger  rectus,  and  is  dis- 
tributed to  the  muscles  which  afterwards  con- 
nect the  thorax  and  abdomen  of  the  perfect 
insect;  and  the  second,  a  smaller  pair,  passes 
diagonally  backwards  below  the  third  rectus, 
to  the  triangular  and  transverse  abdominal 
muscles.  These  are  the  nerves  of  the  thorax 
in  the  larva  of  the  Sphinx.  In  other  species 
there  are  some  marked  differences  in  then- 
mode  of  distribution.  Thus,  in  the  Cossus 
ligniperda,  as  shown  by  Lyonet,  the  first  and 
second  suboesophageal  ganglia  are  closely  ap- 
proximated together,  and  have  no  intervening- 
cords,  and  their  nerves,  consequently,  pass  di- 
agonally backwards,  and  not  transversely,  as 
in  the  Sphinx.  The  nerves  for  the  future  wings 
are  not  derived,  as  in  the  Sphinx,  from  the 
ganglionless  parts  of  the  cord,  but  from  the 
ganglionated  portion  alone,  and  the  distance 
between  the  fourth  and  fifth  ganglia  is  con- 
siderably shortened.  In  the  larva  of  the  nettle 
butterfly,  Vanessa  urtica,  as  formerly  shown 
by  us,*  the  alary  nerves  are  derived  directly 
from  the  cord  itself,  between  the  second  and 
third  and  third  and  fourth  ganglia,  but  they  do 
not  unite,  as  in  the  Sphinx,  with  a  nerve  from 
the  next  ganglion,  but  only  with  the  transverse 
nerves.  But  in  some  of  the  Bombycida,  as  in 
Odoncstis  Rotatoria,  we  have  found  the  same 
connexion  to  exist  between  the  alary  nerves 
and  those  of  the  ganglia,  as  in  the  Sphinx,  and 
a  similar  union  also  between  them  and  the  trans- 
verse nerves.  This  is  particularly  interesting  from 
its  proving  that  three  distinct  branches  enter 
into  the  formation  of  the  nerves  for  the  future 
wings.  We  have  found  a  similar  double  ori- 
gination of  the  alary  nerves  in  the  vermiform 
larvae  of  Hymenoptera,  as  in  Athalia  centifolia ; 
and  Burmeister  has  detected  a  similar  condition 
of  the  same  nerves  in  the  larva  of  one  of  the 
Coleoptera,  Calosuma  sycophanta,  and,  as  we 
shall  presently  see,  a  similar  condition  exists 
even  in  some  perfect  insects.  Burmeister,  who 
observed  these  connexions  of  the  nerves  in 
Calosoma,  and  called  them  auxiliary  connect- 
ing nerves,  has  somewhat  curiously  remarked 
that  he  believes  they  have  not  before  been  ob- 
served in  any  insect,  particularly  in  the  Lepi- 
doptera,  in  proof  of  which  he  adduces  Lyonet's 
description  and  delineation  of  the  nerves  in 
Cossus,  in  which,  as  we  ourselves  have  found, 
they  certainly  do  not  exist.  The  reason  for  this 
difference  of  manner  in  which  nerves  that  are 
given  to  similar  parts  in  insects  of  the  same 
order  and  family  originate,  is  a  matter  worthy 
of  much  consideration. 

Nerves  of  the  abdomen. — All  the  nerves  from 
the  sixth  to  the  terminal  ganglion  belong  to  the 
abdomen,  and  are  nearly  uniform  both  in  num- 

*  Phil.  Trans.  1834. 


ber  and  distribution  in  the  segments.  Each 
ganglion  produces  one  pair  of  large,  and  one 
of  small  nerves,  entirely  distinct  from  the  se- 
ries of  transverse  nerves  (o)  that  lie  loosely 
upon  the  cord. 

It  will  be  remembered  that,  according  to 
our  view  of  the  structure  of  the  cord  and 
nerves,  each  nerve  from  a  gangliated  portion 
of  this  cord  is  formed  of  one  set  of  fibres  from 
the  external  or  gangliated  part,  and  one  from 
the  aganglionic  or  motor  column  (Jig.  400), 
which  passes  over  the  ganglion  («),  but  so  closely 
attached  to  it  as  to  appear  as  if  it  formed  a  part 
of  that  structure.  These,  therefore,  are  quite 
distinct  from  the  transverse  nerves  (c).  The  an- 
terior pair  of  these  nerves  from  the  gangliated 
cord  pass  laterally  across  the  smaller  rectus, 
having  first  received  a  minute  branch  from  the 
transverse  nerves,  and,  while  passing  beneath 
the  larger  rectus,  each  one  gives  off  its  first 
branch  (p),  and  when  passing  between  the 
second  and  third  oblique  muscles  its  second 
branch  (j),  which  is  directed  forwards,  and  a 
little  farther  onwards  its  third  (r),  and  its 
fourth  (s),  which  are  directed  backwards.  The 
main  trunk  (<)  then  crosses  the  great  lateral  tra- 
chea, and  having  received  another  filament 
from  the  transverse  nerve  {n),  divides  into  two 
branches  (t),  which  pass  upwards  between 
the  dorsal  oblique  and  recti  muscles,  and 
are  divided  into  numerous  ramifications. 
About  midway  across  the  dorsal  recti  some  of 
the  branches  form  a  small  plexus  (u),  before 
they  are  ultimately  distributed  to  the  muscles 
and  tegument.  The  two  first  divisions  of  this 
nerve  merit  particular  attention.  The  first  (/>) 
passes  backwards  beneath  the  greater  rectus, 
and  divides  into  two  branches.  The  anterior 
one  (y)  is  distributed  to  the  four  oblique  mus- 
cles, and  to  the  external  or  under  surface  of 
the  rectus,  which,  as  we  shall  presently  show, 
is  supplied  on  its  internal  surface  from  the 
transverse  nerves  (/).  The  second  division 
passes  backwards  and  is  given,  one  portion  to 
the  under  surface  of  the  smaller  rectus,  and 
the  other  to  the  great  oblique,  while  the  ter- 
mination of  this  portion  (w)  is  continuous  with 
a  filament  of  the  second  branch  of  the  trans- 
verse nerves  (/).  Some  branches  from  this 
nerve  pass  between  the  triangular  and  second 
oblique  muscles  (x),  and  others  are  given  to 
the  latero-abdominal.  The  second  branch  (q) 
of  the  great  moto-sensitive  nerve  passes  be- 
neath the  great  oblique,  and  gives  off  branches 
to  the  transverse  abdominal  muscles  (y),  and 
the  latero-abdominal  (z),  while  another  sup- 
plies the  latero-abdominal  (31)  and  the  oblique 
constrictor  of  the  spiracle  (25),  and  then  di- 
vides into  two  portions,  one  of  which  is  given 
to  the  retractor  valvule  (27),  and  the  other 
to  the  transverse  lateral  muscles  (24).  The 
divisions  of  this  branch  of  the  moto-sensitive 
nerve  are  particularly  interesting.  Before  dis- 
secting these  nerves  we  had  supposed  that 
the  constrictor  of  the  spiracle  (25)  and  the 
retractor  of  the  valve  (21)  were  supplied  by 
the  transverse  nerves,  and  hence  were  surprised 
on  finding  that  their  nerves  were  derived  from 
the  great  moto-sensitive  of  the  gangliated  cord, 


INSECTA. 


947 


by  which  it  is  presumed  they  are  thus  endowed 
with  voluntary  power  and  sensation.  But  on 
reflection  it  will  appear  that  this  ought  really  to 
be  the  case.  To  enable  the  insect  to  make  a 
forcible  expiration  and  close  its  spiracle,  which 
is  evidently  an  act  of  volition,  the  great  con- 
strictor of  the  spiracle  ought  to  be  endowed 
with  voluntary  nerves.  Un  the  other  hand, 
since,  as  we  know  from  experiment  that  the 
insect  has  a  voluntary  power  of  closing,  it  must 
also  have  a  similar  power  of  opening  the  orifice, 
and,  consequently,  the  retractor  valvule  ought 
to  be  supplied  from  the  same  source  as  the 
constrictor.  The  remaining  portion  of  the 
trunk  of  these  nerves  passes  forwards  and  out- 
wards, crosses  the  retractor  of  the  spiracle 
and  gives  off  its  third  branch,  which  is  again 
divided,  and  sends  one  portion  backwards  to 
the  anterior  (18)  and  the  transverse  abdominal 
muscles  (17),  and  the  other  forwards  to  the 
transverse  lateral  (23).  The  remaining  portion 
of  the  nerve  is  distributed  to  the  dorsal  muscles 
and  teguments.  The  second  nerve  from  the 
gangliated  part  of  the  cord  is  much  smaller 
than  the  first.  It  passes  diagonally  backwards 
and  outwards,  and  divides  into  two  branches, 
the  first  of  which  is  given  to  the  latero-abdo- 
minal  muscles,  and  the  second  to  the  triangular 
and  transverse  median,  while  the  other  (/c) 
passes  downwards  and  outwards,  and  is  con- 
tinuous with  part  of  the  third  branch  of  the 
transverse  nerves  (i). 

Besides  the  nerves  thus  described  as  belong- 
ing to  the  moto-sensitive  cord  in  the  thorax  and 
abdomen,  there  are  others  that  merit  particular 
consideration,  both  from  the  circumstance  of 
their  lying  loosely  above  the  cord,  and  from 
their  special  distribution.  These  nerves,  which 
were  formerly  distinguished  by  us*  as  trans- 
verse nerves  from  the  direction  of  their  prin- 
cipal branches,  and  as  respiratory  from  their 
special  distribution  to  the  respiratory  organs, 
were  discovered  by  Lyonet,  and  are  delineated 
and  particularly  described  in  his  anatomy  of 
Cossus  ligniperda.  There  is  a  plexus  of  them 
in  every  segment  of  the  thorax  and  abdomen. 
Like  the  alary  nerves  of  the  cord  in  the  thorax, 
there  is  a  little  difference  in  the  distribution  of 
some  of  them  in  the  Sphinx  from  that  of  the 
corresponding  plexus  in  the  Cossus.  In  our 
earlier  examinations  of  these  nervesf  we  be- 
lieved them  to  originate  from  the  posterior  part 
of  each  ganglion  of  the  cord,  and  this  also  was 
the  opinion  of  Lyonet  with  reference  to  those 
in  the  Cossus  which  constitute  the  second  and 
third  plexus  of  the  thorax,  and  the  last  of  the 
abdomen,  and  which,  he  expressly  states,  do 
not  come  from  the  cords,  but  from  the  ganglia. J 
We  have  since  been  satisfied  that  the  plexus  in 
one  segment  is  connected  with  that  in  each 
succeeding  one  by  means  of  a  minute  filament, 
derived  from  the  transverse  portion  of  these 

*  Phil.  Trans.  1832,  part  ii.  p.  389,  and  1834, 
part  ii.  p.  401,  also  1836,  part  ii.  p.  544. 
t  Op.  cit.  1832. 

I  Traite  Anat.  de  la  Chenille,  17G0,  also  1762, 
p.  98  and  204. 


nerves,  and  which,  passing  laterally  over  and 
very  close  to  the  ganglion  of  the  cord,  joins  its 
fellow  of  the  opposite  side,  in  the  middle  line 
behind  it,  to  form  the  longitudinal  portion  of 
the  next  plexus,  such  filament  gathering  a  few 
additional  ones  from  the  upper  or  motor  sur- 
face of  the  cords.    Hence,  as  we  have  stated,* 
these  nerves  are  of  mixed  character,  and  con- 
tain some  voluntary  motor  fibrils.  Each  plexus 
is  formed  of  these  two  filaments,  which,  closely 
approximated  together,  pass  backwards  along 
the  median  line  above  the  cord,  until  they 
arrive  just  before  the  next  ganglion,  where  they 
diverge  nearly  at  right  angles,  and  are  closely 
approximated  to  another  series  of  fibres  that 
runs  in  a  commissural  manner  transversely 
across  the  body,  from  one  side  to  the  other. 
On  each  side  a  filament  (e)  is  given  off  from 
the  transverse  nerves  to  unite  with  the  moto- 
sensitive  (f)  close  to  the  inner  side  of  the 
smaller  rectus.    Near  the  external  margin  of 
that    muscle    it  gives   off  another  branch 
(g),  which  passes  forwards  upon  the  mus- 
cle, unto  which  it  gives  filaments,  and  then 
turns  suddenly  outwards  (/i),  to  join  a  branch 
from  the  great  moto-sensitive  nerve,  while  a 
smaller  branch  is  continued  onwards  to  supply 
the  remainder  of  the  muscle.    This  union  is 
exceedingly  interesting,  and  illustrates  the  fact 
that,  even  in  the  Invertebrata,  some  of  the 
nerves  in  one  part  are  connected  by  loops  with 
those  in  others,  as  noticed  by  physiologists  in 
the  Vertebrated  classes.    The  next  branch  (i) 
of  the  transverse  nerves  is  equally  interesting 
from  the  same  circumstance.    It  is  continuous 
in  the  same  manner  with  another  branch  of  the 
moto-sensitive  {k).    This  branch  is  composed 
of  fibres  that  are  approximated  to  the  transverse 
trunk,  and  pass  some  from  without  inwards, 
and  others  from  within  outwards,  to  form  the 
nerve  («),  leaving  between  them  at  its  base  a 
little  triangular  interspace,  covered  by  a  mem- 
brane and  resembling  the  plexus  (b).  This 
nerve  passes  directly  forwards  until  it  arrives 
at  the  insertion  of  the  greater  recti  (j),  where 
it  gives  off  a  large  branch  to  those  muscles, 
and  then  passing  beneath  the  oblique  muscles, 
unto  which  it  is  distributed,  and  to  the  trian- 
gularis, becomes  connected  by  loops  with  the 
second  pair  of  moto-sensitive  nerves  (k)  in  the 
preceding  segments.     Neither  of  these  two 
branches  have  been  delineated  by  Lyonet  in 
the  Cossus.    The  next  branch  (/)  of  the  trans- 
verse nerves  is  given  to  the  trachea;  and  visceral 
surface  of  the  great  rectus,  after  which  the 
trunk  of  the  nerve  passes  outwards  until  it 
arrives  at  the  tuft  of  tracheal  vessels  which  are 
situated  just  behind  the  spiracle  (F).    It  there 
divides  (?«)  into  two  branches,  one  of  which 
passes  on  each  side  of  these  trachea;.  Some 
filaments  from  the  anterior  branch  pass  inwards 
along  the  trachea  towards  the  alimentary  canal, 
while  others  are  distributed  to  the  transverse 
lateral  muscles,  dorsal  recti,  and  lateral  mus- 
cles of  the  dorsal  vessel.    The  other  division 
of  the  nerve  also  gives  branches  to  the  trachea; 

*  Phil.  Trans,  part  ii.  1836. 

3  Q  2 


948 


INSECTA. 


and  to  the  moto-sensitive  nerve  (ri),  and,  like 
the  other,  the  obliqui  and  recti  muscles  and 
dorsal  vessel.  This  division  of  the  transverse 
nerve  into  two  branches  before  it  arrives  at  the 
trachea  is  not  figured  by  Lyonet  in  the  Cossus. 
In  his  delineation  the  transverse  nerve  crosses 
the  trachea  singly,  posteriorly  to  the  spiracle, 
where  it  communicates,  as  in  the  Sphinx,  with 
the  first  moto-sensitive  nerve  from  the  gan- 
gliated  cord,  but  does  not  give  off  a  large 
branch  anteriorly  to  the  spiracle.  We  are  thus 
particular  in  our  description  of  these  nerves, 
because  it  has  sometimes  been  supposed  that 
their  distribution  is  precisely  the  same  in  all 
Lepidoptera,  but  which  it  is  thus  seen  is  not 
the  case. 

Such,  then,  are  the  origins  and  the  distri- 
bution of  the  nerves  in  the  larvae  of  Lepidop- 
it);,into  the  description  of  which  we  have 
uitcit  dthus  minutely  in  order  to  show  that 
seme  nerves  are  distributed,  more  especially 
than  others,  to  parts  concerned  both  in  the 
organic  functions  and  the  voluntary  motions  of 
the  animal,  and  that  others  are  given  almost 
exclusively  to  parts  that  minister  entirely  to 
sensation  and  volition.  Of  the  first  kind  are 
those  which  we  have  designated  respiratory 
nerves;  of  the  second  are  those  we  have  described 
as  the  moto-sensitive,  the  proper  nerves  of  the 
cord.  The  distribution  of  the  first  so  especially 
to  the  respiratory  organs  is  a  circumstance  which 
justifies  us,  we  think,  in  still  regarding  them  by 
that  designation,  whether  they  be  considered 
as  constituting  a  distinct  system,  as  formerly 
supposed,  or  as  being  of  a  mixed  character, 
connecting  the  organic  with  the  voluntary  func- 
tions of  the  body,  as  suggested  by  Professor 
Miiller,  and  as  we  now  regard  them.  In  our 
earliest  inquiries  into  the  structure  and  uses  of 
parts  of  the  nervous  system  in  insects,  we  first 
described  these  nerves  with  reference  to  func- 
tion, as  respiratory  nerves,  but  it  was  after- 
wards suggested  by  Professor  Grant  that  these 
'  might  be  motor  nerves,'  an  opinion  founded 
analogically  upon  the  existence  of  a  loose  and 
easily  detachable  structure  situated  upon  the 
nervous  cord  in  the  Scorpion  and  the  Centi- 
pede, and  which  was  imagined  to  be  the  motor 
tract,  but  which  has  since  been  shown  to  belong 
to  the  vascular  instead  of  the  nervous  system. 
The  structure  which  we  regard  as  the  true 
motor  column,  we  have  always  found  in  close 
apposition  with  the  sensitive,  and  in  no  instance 
lying  freely  upon  or  loosely  attached  to  it. 
That  the  transverse  nerves  are  indeed  of  a 
mixed  character  may  readily  be  inferred  from 
the  description  we  have  above  given  of  their 
peculiar  structure,  which  was  in  part  noticed  by 
Lyonet,*  who  called  these  nerves  brides 
epiniires.  It  is  distinctly  seen  that  three  sets 
of  fibres  enter  into  the  composition  of  them. 
The  commissural  set,  which  runs  transversely 
across  the  cord  to  each  side  of  the  body,  is  per- 
fectly distinct  from  the  longitudinal  that  form 
the  single  loosely  attached  longitudinal  portion 
of  each  plexus  above  the  cord.    The  pecu- 

*  Op.  cit.  p.  201. 


liarity  of  their  distribution  is  also  as  remarkable 
as  their  structure.  We  have  seen  that  they  are 
given  to  the  muscles  of  the  wings,  not  sepa- 
rately, but  approximated  to  other  nervous 
trunks,  which  are  derived  both  from  the  com- 
pound cord  and  from  the  ganglia ;  that  they  are 
given  to  the  muscle  that  connects  the  alimentary 
canal  to  the  general  muscular  structures  of  the 
body ;  that  they  are  connected  with  the  nerve 
from  ganglia  of  the  cord  in  each  segment, 
are  also  given  separately  to  the  organic  struc- 
tures, the  tracheaa  and  dorsal  vessel ;  and  that 
these  nerves  alone  follow  the  course  of  the 
tracheae  inwards  to  their  distribution  on  the 
alimentary  canal ;  from  all  which  it  may  be  in- 
ferred that  their  function  is  certainly  in  part 
organic ;  while  the  fact  of  their  being  also  in 
part  continuous  with  some  of  the  nerves  from 
the  cord  which  are  distributed  to  voluntary 
muscles  renders  it  equally  apparent  that  they 
are  in  part  also  connected  with  the  function  of 
volition. 

The  nervous  system  of  the  perfect  insect 
differs  considerably  in  the  size  and  relative 
position  of  its  parts  from  that  of  the  larva. 
Instead  of  its  being  almost  equally  distributed 
to  every  segment  of  the  body,  the  greater  pro- 
portion of  it  is  removed  forwards  and  concen- 
trated in  the  head  and  thorax.  This  concentra- 
tion takes  place  in  every  insect  that  undergoes 
a  complete  metamorphosis.  The  great  principle 
upon  which  the  development  of  the  nervous 
system  depends,  is  the  approximation  and 
concentration  of  the  ganglion  of  the  different 
segments,  the  shortening  of  the  cords,  and  the 
formation  of  new  trunks,  by  the  enlargement, 
the  changing  of  place,  and  the  aggregation  of 
several  nerves  into  one  bundle,  occasioned 
and  rendered  necessary  by  other  changes  that 
take  place  in  the  body  at  a  certain  period.  A 
concentration,  therefore,  of  the  nervous  matter 
is  regarded,  both  in  the  perfect  and  larva  con- 
dition, as  a  proof  of  a  higher  stage  of  develop- 
ment in  an  insect  than  when  the  nervous  matter 
is  more  equally  distributed.  On  this  account 
partly  it  is  that  the  Coleoptera  are  considered 
the  higher  forms  of  insects,  because,  in  addition 
to  a  more  perfectly  developed  form  of  the  tegu- 
mentary  skeleton,  there  is  also  in  them  a  concen- 
tration of  the  nervous  masses,  which,  in  the 
more  perfect  species  of  the  order,  are  confined  en- 
tirely to  the  region  of  the  head  and  thorax.  This 
is  the  case  even  in  the  larva  condition  of  some 
of  the  Lamellicornes,  Scarabaida,  Geotrupidte, 
and  Melolonthida,  in  which  the  nervous  masses 
are  confined  to  the  first  five  segments,  and  the 
nerves  radiate  from  them  into  the  abdomen,  as 
formerly  shown  by  Swammerdam  in  Oryctes 
nasicornis.  But  although  an  aggregation  of  the 
nervous  masses  into  one  region  of  the  body  is 
usually,  it  is  not  invariably,  a  proof  or  an 
accompaniment  of  high  development;  since  a 
condition  similar  to  that  of  the  larvae  of  the 
Melolonthida  exists  even  in  some  of  the  lowest 
forms  of  larvae  of  other  orders,  as  in  the  larvae 
or  common  maggots  of  Diptera,  and  in  some 
of  the  perfect  insects,  as  in  the  Gad-fly,  (Estrus 
equi;  while,  on  the  contrary,  a  lengthened 


INSECTA. 


949 


form  of  cord  and  distribution  of  ganglia  exists 
even  in  many  of  the  more  perfect  Coleoptera, 
as  in  the  Carabida  (fig.  407)  and  Hydroplii- 

Fig.  407. 


Nervous  si/stem  of  Carabus  monilis. 

lidx.  Swammerdam  long  ago  showed  this 
aggregation  of  nervous  matter  in  the  maggot  of 
the  cheese-hopper,  and  Burmeister  has  since 
observed  even  a  more  concentrated  form  in  the 
larva  of  Eristalis  tenax,  the  rat-tailed  maggot 


of  cesspools  and  privies.  In  the  latter  instance, 
as  seen  also  by  ourselves,  the  nervous  system 
consists  of  a  short  nodulated  cord,  which  does 
not  extend  beyond  the  three  very  short  thoracic 
segments,  and  the  greater  portion  of  the  body, 
the  nine  posterior  segments,  receives  its  nerves 
directly  from  the  cord  in  the  thorax,  and  not 
from  a  ganglion  in  each  segment.  This  is  a 
circumstance  the  more  remarkable,  if,  as  be- 
lieved by  Straus  and  others,  the  existence  of 
the  ganglia  is  regulated  entirely  by  the  mobility 
of  the  segments  or  the  existence  of  appendages, 
because,  in  these  instances,  the  extremities  of 
those  segments  in  which  the  cord  is  placed 
are  undeveloped,  or  only,  as  in  Eristalis,  in 
the  most  rudimentary  form  and  almost  useless, 
the  sole  organs  of  locomotion  being  the  abdo- 
minal or  false  legs,  while  in  the  common 
maggots  (fig.  358)  both  the  abdominal  and 
thoracic  legs  are  absent,  and  locomotion  is 
performed  equally  by  every  segment  of  the 
body.  In  addition  to  this  it  may  be  stated  that 
in  some  of  the  active  larvae  of  the  most  perfect 
Coleoptera,  as  in  the  Carabida,  there  is  a 
lengthened  form  of  cord  and  a  ganglion  in 
almost  every  segment  of  the  body.  Burmeister 
found  the  brain  and  twelve  sub-cesophageal 
ganglia  in  the  larva  of  Calosoma,  and  yet  the 
insect  possesses  only  six  thoracic  legs,  the 
abdominal  ones  being  entirely  absent,  excepting 
only  the  caudal  leg  or  extremity  of  the  abdo- 
men, in  which  segment  there  is  no  ganglion. 
These  facts  will  prove  that  although  a  concen- 
trated form  of  the  nervous  system  usually  exists 
with  a  more  perfect  development  of  other  parts 
of  the  body,  it  exists  also  when  the  develop- 
ment of  other  parts  is  imperfect.  It  is  not, 
then,  the  immobility  of  the  segments  that  regu- 
lates the  disappearance  of  the  ganglia,  since, 
as  Burmeister  has  justly  remarked,  there  is  as 
little  motion  of  the  segments  of  the  abdomen 
in  the  perfect  Carabida  and  hucanida,  in  which 
cords  and  ganglia  exist,  as  in  the  Melolontludce, 
in  which  they  are  absent.  Neither  is  it  neces- 
sary that  ganglia  should  be  present  as  a  means 
of  supplying  energy  in  segments  upon  which, 
as  m  Eristalis,  the  entire  locomotive  power  of 
the  insect  depends,  or  that  when  ganglia  are 
present  they  are  necessarily  connected  with  the 
function  of  motion. 

The  most  concentrated  form  of  the  nervous 
system  in  all  its  states  exists  in  the  Lamelli- 
cornes,  the  Scarabceidte,  and  MelolonthidiE ; 
but  it  is  remarkable  that  even  in  these  the 
development  of  the  brain  or  supra-cesophageal 
ganglia  is  less  perfect  in  the  larva  state  than 
any  of  the  other  ganglia,  and  is  not  more 
advanced  than  in  the  Lepidoptera,  in  which, 
in  the  caterpillars  of  the  nettle  butterfly,  Vanessa 
urticte,  so  late  as  the  middle  of  the  last  period 
of  the  larva  state  we  have  found  these  ganglia 
very  distinct  from  each  other,  being  only 
approximated  in  the  middle  line  by  their  convex 
surfaces.  Towards  the  latter  period  of  the 
larva  state  they  become  rapidly  more  and  more 
united,  and  at  the  time  of  change  have  formed 
one  continued  mass,  placed  transversely  across 
the  oesophagus.  A  similar  condition  of  the 
brain  exists  in  the  soft-bodied  larva;  of  the 


950 


INSECTA. 


'  Lamcllicornes,  as  shown  in  Swammerdam's 
drawing  of  Oryctes,*  and  Burmeister  has 
delineated  a  like  condition  in  the  larva  of 
Calandra  Sommeri.f  We  have  before  seen 
(fig-  405)  that  such  is  also  the  case  in  the  brain 
of  Timarcha.  From  this  it  would  appear  that 
the  cerebral  ganglia  are  the  parts  of  the  nervous 
system  last  perfected  in  the  larva,  while  it  is 
interesting  to  observe  that  the  reverse  is  the  case 
as  respects  the  terminal  ganglion ;  that  part, 
as  correctly  remarked  by  Professor  Grant,J 
being  the  first  to  advance  forwards  and  become 
united  to  the  penultimate  ganglion,  to  form 
the  great  caudal  mass,  at  an  early  period  of  the 
larva.  This  is  evident  in  the  Timarcha,  in 
which  the  eleventh  and  twelfth  ganglia  have 
coalesced  into  a  single  mass,  while  the  cerebral 
ganglia  only  just  meet  above  the  oesophagus. 
But  this  is  not  the  case  in  the  perfect  insect, 
(fig.  408,)  in  which  the  cerebral  ganglia  (A) 


Fig.  408. 


Nervous  system  of  perfect  state  of  Timarcha  tene- 
bricosa. 

A,  cerebral  mass  or  brain ;  B,  optic  nerves ;  G, 
origin  of  sympathetic. 

have  become  greatly  enlarged,  united  together, 
and  represent  a  distinct  brain,  from  which  pro- 
ceed the  uerves  of  sense,  and  united  by  long 
crura  to  the  medulla  oblongata  (1),  from  which, 
are  given  off  as  before  the  nerves  of  the  organs 

*  Biblia  Nat.  tab.  xviii.  fig.  1. 

+  Zur  Naturgeschichte  dor  Gattung  Calandra, 
fig.  13,  Berlin,  1837. 

t  Phil.  Trans.  1832,  part  ii.  p.  384.  Outlines  of 
Comparative  Anatomy,  p.  193. 


of  manducation.  The  cords  are  enlarged,  as 
also  are  the  three  ganglia  of  the  thorax  and 
their  nerves,  and  a  coalescence  has  taken  place 
between  the  fourth,  fifth,  and  sixth  ganglia, 
their  intervening  cords  being  entirely  obliterated, 
and  the  nerves  aggregated  together  are  now 
derived  from  one  mass,  the  great  meta-thoracic 
ganglion,  the  last  part  of  the  nervous  system  in 
the  thorax.  A  similar  change  has  also  taken 
place  in  the  remaining  part  of  the  cord  and 
ganglia,  which  now  forms  the  abdominal  por- 
tion. The  cord  between  each  of  the  ganglia 
has  been  shortened,  and  the  tenth,  eleventh, 
and  twelfth  are  united  and  form  the  caudal 
mass,  which  is  situated  about  half  way  across 
the  abdomen.  Such  are  the  changes  that  take 
place  in  the  nervous  system  of  an  inferior  type 
of  Coleoptera ;  in  the  higher  forms,  as  in  the 
Melolonthida,  the  series  of  approximated 
ganglia  does  not  extend  beyond  the  middle  of 
the  meta-thorax,  the  cords  being  terminated  by 
a  kind  of  cauda  equina,  all  the  nerves  that  go 
to  the  abdomen  are  aggregated  together  and' 
extended  into  that  region  over  the  post-furca. 
A  similar  structure,  but  in  a  less  complete  form, 
exists  in  the  JJi/tiscida,  in  which,  as  in  the 
Hi/daticus  cinercus,  a  short  cord  is  found  with 
seven  constrictions  upon  it,  corresponding  to 
that  number  of  ganglia  which  probably 
existed  in  the  larva  state,  but  have  nearly  dis- 
appeared during  the  metamorphoses.  But  that 
this  concentrated  form  of  the  nervous  system  is 
not  necessarily  connected  with  high  develop- 
ment of  other  parts  of  the  body  is  further 
shown  in  the  common  Earwig,  Furficula  auri- 
cularia,  in  which  there  are  ten  distinct  sub- 


Fig.  409. 


Nervous  system  of  the  Earwig  ( Forficula  auricularia ). 

oesophageal  ganglia.  The  first,  or  medulla,  is 
large  and  closely  connected  by  very  short  crura 
with  the  brain,  there  being  only  a  narrow 


INSECTA. 


951 


passage  between  the  two  for  the  oesophagus. 
Each  segment  of  the  thorax  contains  a  ganglion, 
the  meta-thoracic  one,  which  gives  nerves  to 
the  wings,  being  the  largest.  In  the  abdominal 
portion  of  the  cord,  which  extends  as  far  as 
the  penultimate  segment,  there  are  six  double 
ganglia  very  distinct  fr,om  each  other.    This  is 
exactly  the  number  found  by  us  in  the  same 
portion  of  cord  in  the  Car-abida:,  although, 
according  to  Burmeister,  there  are  only  five. 
Thus,  then,  in  the  Forficulida,  in  which  there 
is  the  most  extensive  motion  of  the  segments 
of  the  abdomen,  there  is  the  same  number  of 
ganglia  as  in  the  Carabida,  in  which  most 
of  the  abdominal  segments  are  anchylosed 
together  and  immovable,  as  in  the  Lamelli- 
cornes,  in  which  the  whole  of  the  cord  is 
situated  within  the  region  of  the  thorax.  In 
the  oil-beetles,  as  in  Proscarabuvus  vulgaris, 
there  are  as  usual  three  thoracic  ganglia,  the 
largest  being  the  meta-thoracic,  although  the 
proper  wings,  and  scarcely  even  the  elytra,  do  not 
exist.    In  the  abdominal  region  there  are  five 
ganglia,  but  smaller  than  those  of  the  thorax, 
although  it  is  stated  by  Burmeister*  that  these 
ganglia  of  the  thorax  are  larger  than  those  of 
the  abdomen  when  perfect  organs  of  flight  are 
developed,  but  smaller  when  they  are  absent. 
So  far  as  our  own  observations  have  extended, 
we  have  invariably  found  the  thoracic  ganglia 
larger  than   the  abdominal,  whether  organs 
of  flight  exist  or  not,  a  condition  that  might 
naturally  be  expected  whether  the  ganglia  be 
connected  with  the  production  of  nervous  energy 
in  the  parts,  or  be  only  the  centres  of  sensation. 
In  the  full-grown  larva  of  this  insect,  of  which 
we  have  examined  a  considerable  number,  but 
which  at  present  appears  to  be  scarcely  if  at  all 
known  to  naturalists,  we  have  found  twelve  per- 
fectly distinct  sub-cesophageal  ganglia.  Of  these 
the  fifth  was  the  largest  and  separated  from  the 
fourth  only  by  a  very  short  cord,  as  were  also 
the  eleventh  and  twelfth,  besides  which  the 
twelfth  was  larger  than  the  eleventh,  and  ap- 
peared as  if  formed  at  an  early  period  of  two 
approximated  ganglia.    That  in  the  earliest 
state  of  this  insect  there  are  thirteen  sub- 
cesophageal  ganglia  seems  highly  probable.  On 
watching  the  changes  that  tal<e  place  it  is  found 
that  this  double  terminal  ganglion  becomes  united 
to  the  eleventh,  and  that  a  similar  union  takes 
place  between  the  fourth,  fifth,  and  sixth,  so 
that  only  five  separate  abdominal  ganglia  exist 
in  the  perfect  insect.    In  the  Forficula,  which 
does  not  undergo  a  perfect  metamorphosis,  a 
similar  change  appears  to  take  place  at  a  much 
earlier  period,  the  terminal  ganglion  being  dis- 
tinctly formed  of  two  masses,  and  the  ganglion 
of  the  meta-thorax  or  wing-bearing  segment  of 
three.    A  similar  change  appears  also  to  occur 
in  the  Staphylinidee.    In  Creophilus  maxillosus 
(fig.  341),  in  which  the  abdominal  segments  are 
as  freely  moveable  as  in  the  Earwig,  but  which 
undergoes  a  more  complete  metamorphosis, 
there  are  nine  sub-cesophageal  ganglia,  only 
the  last  three  of  which  are  abdominal,  the  last 
five  segments  being  entirely  without  ganglia. 

*  Op.  cit.  p.  281. 


There  is  exactly  the  same  form  and  position  of 
the  nervous  system  in  the  common  species, 
Goerius  olens.  On  comparing  these  circum- 
stances it  is  found  that  a  much  smaller  number 
of  ganglia  in  general  exists  in  those  perfect 
insects  which  have  undergone  a  complete  meta- 
morphosis than  in  the 'larva  state,  and  than  in 
those  that  scarcely  change  their  form.  In  the 
Grylliim,  Acrida  viridisaima  (fig.  410),  there  is 


Fig.  410. 


Nervous  system  of  Acrida  viridissirna. 
A,  brain;  1),  antennas;  B,  optic  nerves  5  d,  man- 
dibular nerve  ;  e,  auxiliary  connecting  nerve  ; 
17,  nerve  of  prothoracic  legs  ;  i,  of  second  pair 
of  legs;  k,  third  pair;  «,  tendon  of  llcxor  mus- 
cle with  its  nerve  accompanying  it  to  its  insertion 
at  extremity  of  the  femur;  c,  second  head  of  the 
same  flexor  muscle  at  the  end  of  the  tibia. 

the  same  number  of  ganglia  as  in  the  Forficula, 
and  a  similar  difference  in  the  size  of  the 
thoracic  ganglia.  But  in  this  insect  there  is 
also  a  closer  lateral  approximation  of  the  abdo- 
minal cords,  and  a  comparatively  smaller  size 
and  more  elongated  form  of  their  ganglia, 
evidently  shewing  a  tendency  to  a  more  con- 


952 


INSECTA. 


centrated  structure,  although  the  cords  still 
remain  more  distinct  from  each  other  than  in 
the  higher  forms  of  Coleoptera.  In  the  Achetida, 
of  which  the  Mole-cricket  affords  us  an  exam- 
ple, as  combining  amazing  strength  and  activity 
with  apparently  highly  developed  instinct,  there 
is  a  more  complete  general  form  of  the  nervous 
system  than  in  the  Acrida.  The  ganglia  of 
the  thorax  are  particularly  large,  but  the  ganglia 
of  the  pro-thoracic  segment,  in  which,  and  in 
the  enormous  limbs,  nearly  the  whole  strength 
of  the  insect,  as  we  have  before  seen,  is  con- 
centrated, does  not  equal  in  size  the  meta- 
thoracic  ganglion,  winch  is  nearly  one-third 
larger  than  either  of  the  others,  although  the 
wings  unto  which  it  is  given,  as  well  as  to  the 
legs,  are  only  of  secondary  importance  as 
organs  of  locomotion,  and  although  a  fifth  and 
much  smaller  ganglion  is  also  attached  to  the 
meta-thoracic.  The  cord  of  the  thorax  is  also 
large  in  proportion  to  the  size  of  the  ganglia. 
In  the  abdomen  the  relative  size  of  the  cord 
is  less  than  in  the  Acrida,  and  there  are  only 
three  small  oval  ganglia  in  it  besides  the  large 
terminal  one,  so  that  the  cord  is  extended 
scarcely  halt  way  through  the  abdomen,  and 
yet  the  whole  of  the  segments,  and  more 
especially  the  posterior  ones,  are  capable  of 
the  most  free  and  extensive  motion.  Thus, 
then,  although  in  these  and  other  forms  of 
insects,  particularly  in  the  Hymenoptera,  Lepi- 
doptera,  and  Diptera,  the  ganglia  are  usually 
aggregated  together  in  certain  segments,  appa- 
rently as  a  means  of  concentrating  the  energies 
of  the  animal  when  one  particular  region  of  its 
body  is  more  actively  employed  than  another, 
the  presence  of  ganglia  in  the  different  segments 
is  not  more  indispensable  to  the  mobility  than 
to  the  sensibility  of  these  parts  to  external  im- 
pressions, since  the  nerves  that  convey  both 
motion  and  sensation  to  them  may  be  derived 
from  ganglia  in  distant  segments,  and  yet  the 
freedom  of  motion  be  not  less  than  when  each 
segment  contains  its  own  ganglion,  and  derives 
its  nerves  immediately  from  it. 

The  structure  of  the  cords  in  the  perfect 
insect  is  almost  as  distinct  as  in  the  larva, 
although  the  whole  of  the  parts  have  become 
more  opaque  and  closely  connected  together. 
In  some  instances  it  is  more  strongly  marked 
than  in  others  after  the  cord  has  remained  for 
some  time  in  spirits  of  wine,  which  is  necessary 
before  an  examination  of  its  structure  is 
attempted.  In  many  of  the  Coleoptera  the 
motor  column  is  seen  passing  in  almost  a  direct 
line  over  the  ganglia  of  the  sensitive,  but  the 
transverse  nerves  are  less  easily  detected,  and 
in  many  instances .  appear  to  have  become 
united  with  the  other  structures.  We  have, 
however,  seen  what  we  regard  as  such  in  the 
GryllidtB,  and  more  distinctly  in  Gryllotalpa, 
lying  upon  and  above  the  motor  column.  In 
some  specimens  we  have  not  found  them  from 
their  being  easily  detached  in  those  insects, 
and,  probably,  removed  during  dissection.  But 
in  these  families  we  have  always  found  the 
motor  column  strongly  marked,  particularly 
while  passing  over  the  ganglia  of  the  thorax. 
In  the  Curubida  (Jig.  411)  the  course  of  the 


motor  column  (6)  is  distinctly  indicated  as  it 
passes  over  the  surface  of  a  ganglion  (a)  by  a 


Fig.  411. 


A  portion  of  the  ganyliated  abdominal  cord  of  Carabus 
monilis. 

a,  a  ganglion  of  the  external  or  sensitive  column  ; 
b,  the  upper  or  motor  column ;  c,  a  ganglion  of 
the  transverse  nerves. 

longitudinal  sulcus.  Just  as  it  is  entering  upon 
and  also  as  it  is  leaving  the  surface  of  the 
ganglion,  the  motor  column  gives  off  a  minute 
branch  to  join  with  the  large  branch  from  the 
ganglion  of  the  sensitive  column,  and  with  it 
form  a  compound  nerve.  At  a  part  of  the 
cord  corresponding  to  the  anterior  margin  of 
each  ganglion,  lying  upon  and  attached  to  the 
motor  column  on  each  side,  is  a  minute  gangli- 
form  mass  (c ),  which  we  regard  as  the  analogue 
of  the  plexus  of  the  transverse  nerves.  It  is  of 
an  obtusely  angulated  shape,  and  is  attached 
to  the  motor  column  by  a  minute  filament  from 
its  base  on  either  side,  and  which  passes  out- 
wards in  the  direction  of  the  anterior  pair  of 
nerves.  From  its  upper  part  in  the  median 
line  extends  another  filament,  the  course  of 
which  we  have  not  been  able  to  follow.  In 
Lucanus  cervus  the  motor  column  is  slightly 
elevated  while  passing  over  the  ganglia,  and  at 
the  anterior  margin  of  each  gives  off  a  filament 
to  join  with  the  nerve  from  that  part  of  the 
cord.  We  have  sometimes  observed  attached 
to  the  motor  column,  just  as  it  had  passed  over 
the  meta-thoracic  ganglion,  on  each  side  a 
little  gangliform  mass,  which  may  possibly  be 
part  of  a  series  of  nerves  like  those  on  the  cord 
in  the  Carabus.  In  the  aculeate  Hymenoptera, 
in  which  the  ganglia  of  the  thorax  are  large,  the 
motor  column  is  readily  observed,  but  in  some 
of  the  Terebrantia,  as  in  the  Turnip-fly,  Athalia 
centifolicc,  when  the  cord  is  examined  by  a 
strong  light,  the  motor  column  is  most  distinctly 
seen  both  on  the  ganglia  of  the  thorax  and 
abdomen,  and  in  this  insect  exhibits  an  appear- 
ance which  we  have  not  observed  in  any  other. 
This  is  a  slight  increase  in  the  diameter  of  the 
column  when  it  has  passed  about  half-way 
over  a  ganglion,  and  a  decrease  to  its  original 
size  when  leaving  it.  Two  filaments  appear  to 
be  given  off  from  the  column  to  join  the  nerve 
from  the  ganglion,  one  as  usual  at  the  anterior 
margin  of  the  ganglion,  and  the  other,  which 
appears  to  be  the  analogue  of  the  transverse 
nerves,  united  to  the  motor  column  when 
about  half-way  over  the  ganglion.  This  en- 
largement of  the  motor  column  is  greatest 
where  it  is  passing  over  the  thoracic  ganglion, 
but  is  best  seen  on  the  abdominal  ones. 
This  fact  has  appeared  particularly  interesting 


INSECTA. 


953 


to  us,  as  we  have  elsewhere  remarked,*  from 
its  seeming  to  be  analogous  to  similar  enlarge- 
ments on  those  parts  of  the  spinal  cord  in  man 
and  other  vertebrata,  from  which  proceed  the 
nerves  to  the  arms  and  lower  extremities  of  the 
body,  and  corresponds  to  the  apparent  greater 
necessity  for  accumulations  of  nervous  matter  at 
those  parts  of  the  cord.  In  Lepidoptera  the  cord 
is  less  easily  examined  in  the  perfect  than  in  the 
larva  state  owing  to  its  increased  opacity,  but  the 
transverse  nerves  are  not  only  distinct  but  have 
been  removed  forwards  and  now  pass  off  on 
either  side  midway  between  the  ganglia. 

The  brain  and  its  nerves  do  not  acquire  their 
full  development  until  near  the  termination  of 
the  pupa  state.  The  supra-oesophageal  ganglia 
(A)  of  the  larva,  which,  for  convenience  of 
description,  we  have  called  after  Burmeister 
the  cerebrum,  are  in  reality  the  analogues  of 
the  corpora  quadrigemina,  and  the  first  sub- 
cesophageal  of  the  medulla  oblongata.  Bur- 
meister has  designated  this  the  cerebellum,  but 
of  that  part  of  the  brain  in  vertebrata  we  believe 
there  is  no  analogue  in  any  of  the  invertebrata. 
Instead  of  the  cerebral  mass  being  divided  into 
two  ganglia,  as  in  the  larva,  it  has  now 
(Jig.  412,  A)  acquired  a  compact  form;  it  is 


Fig.  412. 


A,  brain  of  Timarcha  tenebricosa ;  B,  optic  nerves; 

C,  origin  of  the  sympathetic  and  the  crura ; 

D,  the  medulla  oblongata ;  b,  the  vagus  or 
visceral  nerve  passing  back  from  its  ganglion ; 
e,  lateral  nerves  from  the  ganglion. 

convex  on  its  upper  surface  with  a  slight 
depression  in  the  middle  line,  and  concave  on 
its  under,  to  adapt  it  to  the  form  of  the  oesopha- 
gus, across  which  it  is  placed.  At  its  sides  it 
gives  off  the  large  optic  nerves  (B),  which  are 
almost  equal  to  it  in  diameter.  They  pass 
directly  outwards  and  are  usually  swollen  into 
the  form  of  an  oblong  ganglion,  but  are  again 
constricted  before  they  arrive  at  the  optic  fora- 
men, through  which  they  pass  and  are  imme- 
diately expanded  into  an  immense  number  of 
fine  filaments  for  the  complicated  organ  of 
vision.  There  are  enlargments  upon  these 
nerves  at  their  base  even  in  the  larva  state 
(Jig.  405).  From  the  most  superior  portion  of 
the  cerebrum  originate  the  nerves  of  the  ocelli. 
They  vary  in  number  from  one  to  three,  and 


are  little  pyramidal  elevations  situated  on  each 
lobe,  as  seen  in  Acrida  (jig.  410),  posteriorly 
to  the  antennal  nerves  (D).  They  are  each 
covered  by  a  dark  choroid,  and  in  other  respects 
are  distinct  nerves  of  vision.  When  three  exist, 
as  in  Hymenoptera,  the  third  is  situated  in  the 
middle  line  between  the  others,  and  appears  to 
be  derived  in  part  from  each  lobe,  so  that  in 
this  ocellus  the  vision  of  both  sides  of  the  brain 
is  combined.  In  the  Vespadts,  however,  accord- 
ing to  Burmeister,  the  three  ocelli  originate 
from  a  single  foot-stalk,  and  not  separately,  as 
in  the  Apidte.  On  its  anterior  surface  the 
cerebrum  gives  off  the  antennal  nerves.  These 
also,  in  many  instances,  have  a  ganglionic 
enlargement  at  their  base,  as  is  well  seen  in 
some  of  the  Ichneumonidce  and  other  Hymen- 
optera, and  as  shown  by  Straus  Durckheim 
in  Melolontha.  The  antennal  nerves  vary  in 
position,  being  sometimes  near  the  middle  line 
and  at  others  close  to  the  base  of  the  optic, 
but  in  every  instance  anterior  to  them.  At  its 
anterior  and  inferior  surface  the  cerebrum  pro- 
duces the  two  remaining  pairs  of  nerves.  The 
most  external,  the  glosso-pharyngeal,  unites 
with  its  fellow  of  the  opposite  side  to  surround 
the  oesophagus,  as  in  the  larva.  It  is  seen  very 
distinctly  in  the  pupa  state  (jig.  415,  f)  of  the 
sphinx,  and  also  in  many  perfect  insects,  as  in 
Acrida  (fig.  410).  It  supplies  the  under-sur- 
face  of  the  throat  and  part  of  the  oesophagus, 
and  a  small  branch  is  also  given  from  its  base 
to  the  sides  of  the  mouth.  At  its  inner  side 
originates  the  recurrent  or  vagus  nerve,  which, 
after  passing  a  little  forwards,  ascends  and 
forms  its  ganglion  on  the  upper  surface  of  the 
pharynx,  and  then  passes  backwards  along  the 
oesophagus,  as  in  the  larva.  In  some  insects, 
as  in  Orthoptera,  it  originates  from  a  portion 
of  the  crura,  as  in  Crustacea,  but  its  course 
and  direction  are  always  the  same  although 
appearing  to  vary,  as  we  shall  presently  show 
when  describing  it  as  an  organic  nerve.  The 
sympathetic  originates,  as  in  the  larva,  from 
the  posterior  part  of  the  brain.  One  circum- 
stance that  particularly  distinguishes  the  brain 
from  the  other  ganglia  is  its  more  uniform 
opacity  and  greater  softness,  and  disposition  to 
deliquesce  when  exposed  for  a  short  time  to 
the  air.  It  is  usually  larger  than  most  of  the 
other  ganglia,  excepting  perhaps  the  meso- 
thoracic.  In  Hymenoptera  it  is  larger  than  in 
other  insects,  a  curious  circumstance  this  if  it 
may  be  supposed  to  have  any  reference  to  the 
comparative  instinct  of  different  species.  In 
Diptera  and  Orthoptera  it  is  also  of  great  size. 
We  were  once  desirous  of  knowing  whether  it 
contains  any  cavities  or  ventricles,  but  after  the 
most  careful  search  we  have  been  unable  to 
detect  any.  It  is  an  almost  homogeneous  mass, 
penetrated  throughout  its  whole  substance  by 
minute  air-vessels,  which  ramify  within  it  and 
also  in  the  substance  of  the  optic  nerve.  This 
is  one  of  the  circumstances  that  lead  us  to 
suspect,  as  formerly  suggested  by  Dr.  Kidd  in 
his  anatomy  of  the  Mole-cricket,*  tliat  the 
course  of  the  blood  in  the  different  structures 


*  Prize  Essay,  p.  11. 


*  Phil.  Trans.  1826. 


954 


INSECTA. 


always  accompanies  that  of  the  trachea.  The 
crura  vary  much  in  length  in  different  species. 
In  Neuroptera,  Hymenoptera,  Lepidoptera, 
Diptera,  and  Homoptera  they  are  short  and 
thick,  and  form  with  the  medulla  a  thick  collar, 
through  which  the  oesophagus  passes  as  a  narrow 
lube;  but  in  the  Gryllidte  (Jig.  410),'  and 
more  particularly  in  the  Lucanida:  (fig.  413), 
they  are  excessively  elongated,  and  they  are 
also  of  great  length  in  the  Timurcha.  The 
medulla  oblongata  varies  much  in  size ;  in  some, 
as  in  the  Lepidoptera,  it  is  as  large  as  one  of 
the  lobes  of  the  cerebrum,  while  in  others  it  is 
scarcely  thicker  than  the  crura.  It  is  always 
largest  where  large  nerves  are  required  for  the 
parts  of  the  mouth,  which  in  all  cases  are 
derived  from  it.  In  this  respect  there  is  a  striking 
analogy  between  it  and  the  medulla  oblongata 
of  vertebrata.  The  anterior  pair  of  nerves  from 
this  part  are  given  to  the  labium  and  lingua, 
while  the  two  next  pairs  are  given  to  the  man- 
dibles and  maxilla.  In  the  distribution  of  these 
nerves  there  is  great  similitude  to  that  of  the 
fifth  pair  in  the  higher  animals.  In  the  larva 
state  these  nerves  are  always  distinct  from  each 
other,  but  in  the  perfect  they  are  often  united 
at  their  base  into  one  trunk.  This  is  the  case 
in  the  Timurcha  and  Gryllida.  The  anterior 
pair  is  the  largest  in  mandibulated  insects, 
and  supplies  the  powerful  mandibles,  while 
the  posterior  pair  is  given  to  the  maxilla;.  The 
union  of  these  nerves  at  their  base  is  interesting 
from  the  circumstance  that  during  manducation 
a  consentaneous  movement  of  these  parts  is 
required,  since,  while  the  mandibles  are  em- 
ployed in  chewing,  the  maxilla?  are  also  em- 
ployed in  turning  and  assisting  to  pass  the  food 
into  the  pharynx.  In  the  Sphinx  ligustri,  and 
other  Lepidoptera,  the  chief  portion  of  the  man- 
dibular nerve  has  disappeared  in  the  perfect 
state,  in  consequence  of  the  atrophy  which  has 
taken  place  in  the  mandibles  during  the  trans- 
formations ;  but  one  branch  of  the  nerve  which 
exists  in  the  larva  state  appears  to  have  become 
approximated  to  the  maxillary  nerve,  which  is 
now  greatly  elongated  and  given  to  the  pro- 
boscis, the  representative  of  the  maxillae  of 
the  larva.  The  branch  that  appears  to  have 
belonged  to  the  mandibular  nerve  is  extended 
along  the  concave  or  inner  side  of  each  half  of 
the  proboscis,  where  the  sense  of  taste  may 
justly  be  suspected  to  reside,  and  is  traceable 
very  nearly  to  the  extremity  of  the  organ,  where 
the  papillae  we  formerly  noticed  are  situated, 
and  in  the  direction  of  which  this  nerve  is 
extended.  From  this  we  believe  it  to  be 
analogous  in  function  to  the  gustatory  portion 
of  the  fifth  nerve  in  vertebrata.  In  Lucanus 
cervus  the  mandibular  nerve  is  of  great  length, 
and  is  so  extensively  developed  as  to  afford 
almost  a  proof  of  the  elongation  of  nerves 
during  the  metamorphoses  of  the  insect.  We 
have  traced  this  nerve  from  its  origin  (Jig. 
413,  c )  into  the  base  of  the  mandible,  which  it 
enters  a  little  external  to  the  insertion  of  the 
flexor  muscles,  where  it  is  divided  into  three 
trunks,  the  inner  one  of  which  we  have  traced 
very  nearly  as  far  as  the  apex  of  the  mandible. 
The  other  two  are  situated  more  externally. 


Fig.  413. 


Nervous  system  of  Lucanus  cervus. 

A,  the  brain;  B,  optic  nerves;  C,  sympathetic; 
D,  antennal  nerves ;  a,  ganglion  of  the  vagus 
nerve;  b,  the  nerve;  i,  its  division  on  the  oeso- 
phagus ;  d,  nerve  to  the  first  pair  of  legs ;  /, 
nerve  to  the  wings,  giving  off  at  its  base  a  small 
nerve  to  the  elytra ;  g,  nerve  to  second  pair  of 
legs  ;  k,  to  third  pair ;  I,  abdominal  cord  and 
ganglia. 


INSECTA. 


955 


The  most  posterior  one  is  given  to  the  muscles 
within  the  head,  and  the  other  passes  along  the 
outward  part  of  the  interior  of  the  mandible  to 
its  apex.   The  medulla  oblongata  with  the  con- 
tinuation of  the  nervous  cord  in  all  Coleoptera 
passes  under  the  bony  arch  or  tentorium  at  the 
base  of  the  skull,  protected  on  both  sides,  as 
in  Melolontha,*  Dyticus,  and  Hydrous,  by  the 
lamina  posteriores,  which  inclose  it,  as  in  a 
canal,  distinct  from  the  oesophagus,  that  passes 
along  above  it,  and  from  which  it  is  separated 
by  a  fine  fibrous  membrane.    The  crura  and 
the  base  of  the  cerebrum  rest  upon  and  are 
partly  protected  on  each  side  by  the  lamina 
squamosa,  which  thus,  as  it  were,  form  a  kind 
of  internal  skeleton  for  the  protection  of  the 
soft  part.    The  optic  nerves  at  their  base  rest 
upon  the  lamina?  in  their  course  to  the  eye, 
and  extend  as  far  outwards  as  the  lamina 
orbitales  through  the  foramen  in  which  they 
pass,  and  are  immediately  expanded  into  an 
immense  number  of  filaments  which  form  part 
of  the  organ  of  vision,  as  we  shall  presently 
describe.  The  whole  of  the  cerebrum  is  loosely 
covered  by  a  fine  transparent  membrane  that  is 
continuous  with  the  fibrous  membrane  that 
covers  the  cord.    In  some  instances,  as  in  the 
Bombus  terrestris,  it  is  very  distinct,  and  in 
others,  as  shown  by  Burmeister,  is  studded 
with  minute  opaque  rounded  elevations,  arranged 
in  the  form  of  squares.    It  appears  to  be 
reflected  along  the  course  of  the  optic  nerves, 
and  to  be  continuous  in  part  with  the  margins 
of  the  lamina  squamosa,  and  separates  the 
brain  from  the  muscles,  by  which  it  is  on  almost 
every  side  inclosed.  In  Lucanus  cervus,  instead 
of  the  medulla  passing  under  a  simple  arch 
or  tentorium,  the  laminee  laterales  are  approxi- 
mated and  form  a  double  ring  (fig.  388, 
through  the  inferior  of  which,  as  through  the 
ring  of  a  vertebra,  the  nervous  cord  passes  in 
its  course  to  the  prothorax.    In  the  Orthoptera, 
as  in  Blatta  Americana  and  Gryllotalpa,  we 
have  seen  the  same  structure,  but  in  these  the 
ring  is  lengthened  and  forms  a  more  distinct 
canal.    In  the  Hymenoptera,  as  in  the  hornet 
and  humble-bee,  the  form  of  the  part  is  exactly 
the  same,  and  the  cord  passes  through  a  short 
bony  ring  in  its  passage  to  the  thorax.  There 
is  a  somewhat  similar  structure  in  Lepidoptera 
as  in  Sphinx  ligustri,  only  that  it  is  much  less 
complete,  the  arch  being  simply  a  bar  extended 
across  the  occipital  foramen  and  dividing  it 
into  two,  through  the  lower  one  of  which  the 
cord  passes,  and  also  on  each  side  of  it  the 
flexor  muscles  of  the  head.    A  like  form  exists 
in  the  Homoptera,  but  much  less  perfect. 

The  cord  and  nerves  of  the  thorax,  which 
are  usually  much  larger  than  those  of  the 
abdomen,  we  regard  as  the  proper  cerebro- 
spinal system,  and  the  abdominal  portion  as 
the  caudal.  This  is  the  view  taken  of  these 
parts  by  Burmeister,  with  whose  opinion  we 
perfectly  coincide.  The  prothoracic  ganglion 
is  situated  immediately  before  the  ante-furca, 
between  which  the  cord  passes  to  the  meta- 
thorax,  when  it  forms  a  great  ganglion  anterior 

*  Straus,  Considerat.  &c. 


to  and  beneath  the  medifurca,  and  then  passes 
onwards  over  the  post-furca  to  the  abdomen. 
In  the  Lamellicornes  and  others  in  which  the 
cord  terminates  in  the  thorax,  and  the  nerves 
radiate  from  thence  into  the  abdomen  as  a 
cauda  equina,  they  pass  over  the  post-furca  in  a 
bundle,  and  do  not  separate  until  they  enter 
the  latter  region.  In  the  Gryllidce,  in  whicli 
most  of  the  segments  are  equally  developed,  and 
th  ere  are  three  large  thoracic  ganglia,  the  meta- 
thoracic  one  is  situated  in  the  middle  of  the 
segment,  and  the  succeeding  or  fourth  sub- 
oesophageal  ganglion  on  the  rudimentary  post- 
furca.  In  the  Hymenoptera,  in  which  there 
are  but  two  ganglia  in  the  thorax,  the  anterior 
and  smaller  one  is  situated  at  the  margin  of  the 
metathorax,  and  the  great  ganglion  at  the 
posterior,  and  the  cord  continued  from  it  passes 
through  a  strong  bony  canal  or  ring  in  the 
medifurca,  somewhat  resembling  that. which 
exists  in  the  head,  and  then  forms  a  smaller 
ganglion  before  it  enters  the  abdomen.  In 
the  Hemiptera,  in  which  it  has  been  supposed 
that  there  is  only  one  ganglion  in  the  thoracic 
region,  the  cord  between  the  medulla  and  pro- 
thoracic  ganglion  is  exceedingly  short,  but  is 
protected  in  its  passage  through  the  elongated 
neck,  and  then  is  developed  into  a  large  pro- 
thoracic  ganglion,  the  second  ganglion  being 
situated  in  the  middle  of  the  meso-thorax  before 
the  medifurca.  These  parts  are  very  distinct 
in  Nepa  grandis.  In  the  Lepidoptera,  in  which 
the  form  of  the  thorax  is  more  compact  even 
than  in  the  Hymenoptera,  the  cord  passes  on 
each  side  of  the  medifurca  or  part  to  which 
the  triangular  muscles  are  attached,  and  is  so 
much  enlarged  as  to  appear  almost  like  a  por- 
tion or  continuation  of  each  of  the  two  great 
ganglia  situated  before  and  behind  it.  The 
cords  and  ganglia  of  the  thorax  are  covered  in 
by  a  strong  white  membrane  like  those  of  the 
head.  In  the  Lepidoptera  this  is  particularly 
firm,  so  that  the  nervous  system  is  not  included 
within  the  cavity  of  the  thorax. 

In  the  distribution  of  the  nerves  there  are 
some  peculiarities.  We  have  seen  the  auxil- 
iary connecting  nerves  of  Burmeister,  as  shown 
by  us  formerly  in  the  larva  of  the  Sphinx* 
(fig,  406),  in  many  species.  They  exist  be- 
tween the  cord  and  all  the  ganglia  of  the 
thorax  in  the  Gryllida  (fig.  410,  e,  h,)  and 
between  the  cord  and  the  nerves  to  the  wings 
in  Athalia  centifolia  and  Panorpa  communis. 
We  have  seen  them  also  in  Oiceoptorna,  Pro- 
scarabaus,  Creophilus,  Lampyris,  Forficula, 
Blatta,  and  even  in  an  imperfect  form  in 
(Eslrus,  as  well  as  in  some  of  the  Lepidoptera. 
They  are  invariably  connected  with  the  nerves 
to  the  wings,  of  which  they  form  one  portion, 
and  are  far  more  frequently  met  with  than 
Burmeister  appears  to  have  supposed.  We 
formerly!  remarked  on  a  peculiarity  in  the  dis- 
tribution of  the  thoracic  nerves  in  the  Sphinx, 
and  the  opinion  then  ventured  with  regard  to 
its  nature  we  have  since  had  reason  to  believe 
was  well  founded.   We  have  seen  the  auxiliary 

*  Phil.  Trans.  1832/part  ii.  p.  387-8. 
t  Phil.  Trans.  1834,  part  ii.  p.  394. 


956 


INSECTA. 


connecting  nerves  in  the  larva  forming  one  por- 
tion of  the  nerves  for  the  future  wing  of  the  per- 
fect insect.  The  nerves  for  both  pairs  of  wings 
are  then  derived  separately  from  two  portions  of 
cord  and  two  distinct  ganglia,  and  this  is  the 
state  in  which  they  are  also  found  soon  after 
the  insect  has  changed  to  a  pupa  (jig.  414). 

Fig.  414. 


Pupa  of  Sphinx  ligustri.    (Newport,  Phil  Tram.) 

The  connecting  nerves  are  then  derived  from 
the  cord  (e,  h),  and  being  joined  each  to  the 
first  nerve  from  the  next  ganglion  assist  to  form 
the  future  alary  nerves  (f,  i).  Now  as  the 
change  to  the  perfect  insect  proceeds,  the  second 
ganglion  (2)  becomes  approximated  to  the  third 
(5),  which  gradually  disappears,  and  the  cord 
between  it  and  the  fourth  becomes  enlarged 
and  shortened,  and  passes  on  each  side  of  the 
insertion  of  the  muscles  in  the  centre  of  the 
meso-thorax,  the  cord  between  the  second  and 
third  ganglion  having  also  become  obliterated, 
so  that  there  is  then  no  ganglion  intervening 
between  the  origins  of  the  two  pairs  of  wings, 
but  only  a  portion  of  cord.  The  nerves  for  the 
two  pairs  of  wings  then  approach  each  other 
diagonally,  the  anterior  pair  being  directed 
backwards,  and  the  posterior  forwards,  until 
they  meet  and  form  a  plexus,  their  roots  still 
continuing  distinct  from  each  other;  the  root 
of  the  anterior  being  .derived  from  the  cord 


posterior  to  the  united  second  and  third  gan- 
glia, and  that  of  the  posterior  from  the  cord 
connected  with  the  united  fourth  and  fifth  gan- 
glia. After  forming  the  plexus,  the  nerves  are 
again  separated  and  given  to  the  anterior  and 
posterior  wings.  The  reason  for  this  curious 
union  and  complexity  in  the  distribution  of  the 
nerves  to  the  wings  is  not  at  first  very  evident, 
but  on  a  little  reflexion  it  is  found  to  be  regu- 
lated by  one  of  those  beautiful  provisions  in 
the  animal  economy  by  which  the  most  perfect 
harmony  in  the  exercise  of  all  the  functions  of 
the  body  is  preserved.  The  wings,  the  most 
powerful  and  most  constantly  employed  organs, 
are  not  merely  required  to  act  with  energy,  but 
in  the  most  perfect  unison  with  each  other, 
more  especially  in  insects  of  long-continued 
or  rapid  flight,  and  hence  must  be  supplied 
with  power  from  the  same  centre,  not  merely 
that  of  voluntary  motion  but  also  of  sensation. 
That  this  is  the  reason  for  this  curious  union  of 
the  nerves  for  the  wings  seems  apparent  from 
the  circumstance  that  it  exists  in  very  many 
tetrapterous  insects  of  rapid  or  powerful  flight, 
as  in  the  Apida  and  Ichneumonidie,  while  in 
others,  even  of  the  same  order,  as  in  Athalia 
cenlifuUa:,  which  is  well  known  to  fly  heavily 
and  but  a  short  distance,  there  is  no  such  com- 
bination. In  the  Scorpion-fly  also,  Panorpa 
communis,  it  is  absent,  and  the  alary  nerves 
originate  by  double  roots  without  forming 
a  plexus  as  in  the  larva  of  the  Sphinx,  while 
the  flight  of  the  insect  is  sluggish  and  but  of 
short  duration.  Besides  this  it  may  be  re- 
marked that  in  many  Coleoptera  in  which  the 
anterior  wings  or  elytra  are  merely  elevated  and 
nearly  motionless  during  flight,  the  nerves  are 
derived  separately  from  the  cord,  and  proceed 
to  their  destination  without  being  first  com- 
bined in  a  plexus. 

The  cord  and  nerves  of  the  abdomen,  as  before 
stated,  we  regard  merely  as  a  cauda  equina. 
We  have  before  explained  the  varieties  in  the 
formation  of  the  cord  in  different  insects,  and 
need  but  further  remark  that  in  each  instance 
the  cord  in  the  abdomen,  as  in  other  parts,  is 
covered  in  by  a  strong  fibrous  membrane,  which 
separates  it  from  the  cavity  of  the  abdomen. 
In  the  Gryllidm  we  have  distinctly  recognised 
muscular  fibres  running  transversely  above  the 
cord  from  one  side  of  the  body  to  the  other. 
They  have  also  been  observed  by  Burmeister,  who 
supposes  them  to  assist  in  the  function  of  respi- 
ration by  contracting  the  segments,  and  thus 
aiding  in  the  act  of  expiration.  We  have  seen 
similar  trans-muscles  lying  above  the  mem- 
brane that  binds  down  the  nervous  cord  in  the 
abdomen  of  Bombus  terrestris.  The  mem- 
brane is  continuous  with  that  which  covers  the 
cord  in  the  thorax.  A  similar  membrane  was 
formerly  noticed  by  Lyonet  in  the  Cossus,* 
and  subsequently  by  ourselves  in  the  Sphinx.f 
Between  this  membrane  and  the  cord  there  is  a 

*  Recherches  sur  l'Anatomie  et  les  Metamor- 
phoses des  differentes  Especes  d'Insectes,  ouvrage 
posthume  de  Pierre  Lyonet.  Paris,  1832,  fig.  18, 
p.  52. 

t  Phil.  Trans.  1834,  part  ii.  p.  395,  pi.  xiv. 
fig.  9. 


r 


INSECTA. 


vessel  which  we  regard  as  connected  with  the 
circulatory  system,  as  we  shall  hereafter  show. 

As  nerves  of  organic  function,  we  have  now 
to  consider  those  which  are  especially  given  to 
the  different  internal  organs,  and  not  to  the 
voluntary  muscles.  Having  already  considered 
the  transverse  nerves,  which  are  distributed  so 


957 

especially  to  the  respiratory  organs,  as  nerves  of 
mixed  character,  those  which  we  regard  more 
especially  under  the  above  designation  are  the 
si/ in  pathetic  and  the  vagus  or  visceral  nerves. 
The  sympathetic,  or  anterior  lateral  ganglia 
(Jig.  415,  C),  are  situated  two  on  each  side  of 
the  oesophagus  behind  the  brain,  and  anterior 


Fig.  415. 


Brain  and  nerves  of  tlie  head  and  first  segment  of  a  pupa  of  Sphinx  ligustri. 

A,  brain;  B,  optic  nerves  ;  C,  anterior  lateral  or  sympathetic  ganglia;  D,  antcnnal 
nerves  ;  E,  frontal  ganglion  of  the  recurrent  or  vagus  nerve.    (Newport,  Phil.  Trans.) 


to  the  great  muscles  of  the  oesophagus  and  pha- 
rynx. They  are  of  considerable  size,  being 
each  about  one-third  as  large  as  one-half  of  the 
cerebrum,  and  they  are  connected  with  most  of 
the  other  nerves  in  the  head.  Thus,  besides 
their  connexions  {a)  with  the  brain,  one  nerve 
passes  forwards  beneath  the  optic  nerves,  and 
joins  with  a  minute  filament  from  the  nerve  to 
the  antennae,  (g,)  and  also  with  one  to  the 
mandibles,  while  another  passing  across  the 
oesophagus  is  united  with  the  main  trunk  of  the 
visceral  or  vagus  nerve  (e),  as  it  passes  along 
to  the  stomach,  and  another  branch  joins  with 
the  first  set  of  transverse  nerves  (/<),  while  other 
filaments  passing  outwards  are  distributed  to 
the  muscles  of  the  oesophagus  and  pharynx. 
This  latter  fact,  which  we  have  most  distinctly 
ascertained  in  Meloe  cicatricosus,  a  large  species 
well  adapted  both  for  an  examination  of  this 
and  of  the  visceral  nerve,  is  particularly  inte- 
resting from  the  circumstance  that,  after  the 
most  careful  examination,  we  could  not  find 
any  other  nerve  given  to  those  muscles  (fig. 
416,  C).  We  have  observed  a  similar  distri- 
bution to  the  muscles  of  the  oesophagus  in  Lu- 
canus,  and  also  in  the  Sphinx,  so  that  from  their 
connexions  we  may  justly  conclude  these  gan- 
glia to  constitute  at  least  a  portion  of  the  true 
sympathetic  system.  From  their  relative  situ- 
ation they  appear  to  be  analogous  to  the  supe- 
rior cervical  ganglia  of  the  sympathetic  in  Ver- 
tebrata.    It  is,  however,  an  interesting  fact,  as 


noticed  by  Burmeister,*  that  these  ganglia  ap- 
pear to  be  largest  in  some  of  those  insects  ire 
which  the  recurrent  nerve  which  we  have  de- 
scribed as  the  vagus  is  least  developed.  Thus,, 
as  shown  by  Muller,  Brandt,  and  Burmeister, 
these  ganglia  of  the  sympathetic  system  have 
a  large  size  in  the  Orthoptera,  and,  instead  of 
being  traceable  scarcely  beyond  the  region  of 
the  head,  send  off  one  or  two  branches  which 
run  along  the  sides  of  the  oesophagus  to  a  great 
distance,  while  the  recurrent  or  vagus  nerve, 
after  uniting  with  these  ganglia  behind  the 
brain,  appears  to  terminate  or  be  lost  in  the 
nerves  that  originate  from  them.  In  Gri/llus 
migratorius,  Burmeister  has  shownf  that  after 
the  recurrent  nerve  has  formed  a  minute  gan- 
glion jugt  behind  the  brain,  and  united  with 
the  first  of  these  sympathetic  ganglia,  it  ap- 
pears to  terminate,  while  the  same  ganglion 
sends  off  posteriorly  two  branches,  which  run 
along  the  upper  surface  of  the  oesophagus,  where 
the  external  one  forms  a  small  ganglion,  and 
that  the  second,  or  most  external  of  these  ante- 
rior lateral  ganglia,  also  sends  a  large  nerve 
backwards,  at  the  side  of  the  oesophagus,  as  far 
as  the  crop,  where  it  forms  a  ganglion  and 
sends  off  nerves,  and  at  the  hinder  part  of  the 
crop  a  second  ganglion,  from  which  nerves  are 
given  to  the  coecal  appendages  of  the  alimen- 

*  Op.  cit.  p.  288. 
t  Id.  pi.  xxxi.  tig.  6. 


958 


INSECTA. 


tary  canal.  Muller*  had  previously  shewn  a 
similar  arrangement  of  these  ganglia  in  Gryllo- 
talpa  vulgaris,  and  Brandt  f  has  since  further 
elucidated  the  distribution  of  these  structures 
in  the  same  insects.  We  have  ourselves  re- 
cently found  a  somewhat  similar  distribution  of 
these  nerves  in  one  of  the  Coleoptera,  Bupres- 
tis  chrysis,  in  which  the  first  of  the  anterior 
lateral  ganglia,  on  each  side,  besides  its  con- 
nexion with  the  brain,  gives  off  three  distinct 
nerves,  one  of  which  passes  outwards  to  the 
muscles  of  the  oesophagus  and  pharynx,  and 
another  inwards  to  unite  with  the  great  trunk 
of  the  recurrent  nerve,  while  the  third  passes 
backwards  for  a  short  distance,  and  then  forms 
the  second  of  the  lateral  ganglia,  from  which, 
in  like  manner  also,  proceed  three  other  nerves. 
The  first  of  these  passes  outwards  to  the  sides 
of  the  oesophagus,  and  the  second  inwards  to 
join  a  large  ganglion  formed  at  the  extremity 
of  the  recurrent  nerve,  while  the  third  branch 
is  of  considerable  length  and  traceable  for  a 
great  distance  along  the  sides  of  the  oesophagus. 
From  the  ganglion  at  the  termination  of  the 
recurrent  nerve,  and  which  most  certainly  be- 
longs to  this  trunk,  are  also  given  off  two  nerves, 
which  are  soon  again  divided,  and  distributed 
along  the  posterior  part  of  the  oesophagus. 
From  these  connexions,  and  the  relative  size 
of  the  parts,  it  still  appears  to  us  that  although 
the  sympathetic  and  recurrent  nerves  are  most 
intimately  connected,  and  appear  in  certain 
instances  almost  to  supply  the  place  of  each 
other,  there  is  reason  for  still  considering  them 
as  distinct,  and  for  describing  the  latter,  as  we 
formerly  designated  it,}  as  the  vagus. 

The  vag7(S,  or  visceral  nerve  of  Professor 
Muller,  after  arising,  as  in  the  larva,  from  the 
anterior  part  of  the  base  of  the  cerebrum,  and 
forming  a  ganglion  on  the  upper  surface  of  the 
pharynx,  always  passes  backwards  beneath  the 
brain,  along  the  middle  line  of  the  oesophagus. 
We  shall  first  describe  its  course  in  Lepidopte- 
rous  insects,  and  point  out  what  we  conceive  to 
be  its  analogies  to  the  vagus  of  vertebrata.  In 
the  Sphinx  it  originates  in  the  perfect  insect,  as 
in  the  larva,  from  the  lowest  part  of  the  anterior 
surface  of  the  brain  by  two  roots,  one  on  each 
side,  which  we  regard  as  analogous  to  the  two 
vagi  in  the  higher  animals.  Each  root  gives  off 
from  its  base  a  small  branch  to  the  sides  of  the 
mouth,  after  which  the  two  roots  ascend,  and 
meeting  above  the  pharynx,  form  the  frontal 
ganglion,  from  the  anterior  surface  of  which  a 
few  nerves  are  given  to  the  mouth  and  palate, 
and  also  to  the  bifurcation  of  the  dorsal  vessel, 
which,  after  having  passed  along  the  oesopha- 
gus and  beneath  the  brain,  is  divided  in  front  of 
the  brain  into  several  branches.  The  frontal 
ganglion  at  the  junction  of  these  roots  of  the 
vagus  we  regard  as  analogous  to  the  enlarge- 
ment on  the  vagus  nerve  in  vertebrata  after  it 
has  passed  out  of  the  skull  by  the  foramen  la- 
cerum  posterius.  From  the  ganglion  thus 
formed  by  the  approximation  of  the  two  roots, 
a  single  trunk  passes  backwards  along  the  me- 

*  Nova  Acta  Curios.  Nat.  vol.  xiv. 
f  Annal.  des  Sciences  Natur,  torn.  v. 
t  Phil.  Trans.  1832. 


dian  line,  lying  upon  the  oesophagus  and  be- 
neath the  dorsal  vessel,  and  giving  to  both  se- 
veral blanches  in  its  course.  When  arrived  at 
the  dilatation  of  the  oesophagus,  the  air-bag  or 
crop,  it  first  distributes  a  few  filaments  to  that 
part,  and  then  divides  into  two  primary 
branches,  which  run  along  the  sides  of  the 
stomach,  and  are  again  subdivided  and  distri- 
buted to  it.  Behind  the  brain,  the  vagus  in  the 
Sphinx  receives  but  one  branch  of  communica- 
tion on  each  side  from  the  sympathetic  ganglia, 
which  connexions  appear  to  be  analogous  to 
those  between  the  vagus  and  sympathetic  in 
vertebrata.  In  passing  along  the  median  line 
of  the  oesophagus,  the  single  vagus  in  insects 
is  in  close  relation  with  the  anterior  or  aortal 
portion  of  the  dorsal  vessel,  which  may  repre- 
sent the  two  carotids  of  the  higher  animals 
united,  and  thus  its  relation  to  these  parts  is 
also  precisely  similar  to  that  of  the  vagus,  caro- 
tids, and  oesophagus  in  these  animals.  There  is 
a  like  analogy  in  its  distribution  to  the  anterior 
part  of  the  stomach,  beyond  the  middle  portion 
of  which  it  has  never  yet  been  traced.  At  its 
point  of  division  the  single  vagus  nerve  often 
forms  a  very  distinct  ganglion,  as  in  the  Melcie 
(Jig.  416,  i).  This  is  the  usual  distribution  in 
a  large  majority  of  insects,  more  particularly 
in  the  Lepidoptera,  Coleoptera,  Neuroptera, 

Fig.  416. 


Brain  and  vagus  nerve  of  MeToe  cicairicosus. 

Hymenoptera,  and  in  many  of  the  Orthoptera. 
In  Luc  anus  cervus  (Jig.  417),  the  nerve,  conti- 
nued backwards  from  the  frontal  ganglia  (a),  is 
of  large  size  until  after  it  has  passed  beneath  the 
brain,  and  given  off  a  minute  branch  on  each 
side  to  the  dorsal  vessel  and  oesophagus,  after 
which  it  becomes  on  a  sudden  much  smaller, 
and  forms  a  second  small  ganglion,  (e,)  which 
is  connected  on  each  side  by  a  single 
branch  with  the  sympathetic  ganglia  (C,)  which 
have  assumed  an  elongated  form,  and  are 
greatly  enlarged.  After  this  the  vagus  nerve 
is  continued  as  a  single  trunk,  (&,)  until  it 


INSECTA. 


959 


has  passed  half-way  along  the  oesophagus, 
(Jig.  428,  h,)  whenit  divides  into  two  branches, 
which  pass  on  each  side  of  the  oesophagus  as  far 
as  the  gizzard,  (i,-)  where  each  forms  a  very 
minute  ganglion,  from  which  are  given  a  few 
filaments  to   the  substance  of  the  gizzard. 


Fig.  417. 


Brain,  sympathetic  ganglia,  and  vagus  nerve  of 
Lucajius  cervus. 


Each  nerve  thus  passes  on  to  the  stomach,  (k,) 
and  we  have  succeeded  in  tracing  it  about  half-way 
along  that  organ,  when  it  can  be  followed  no  far- 
ther, being  lost  by  minute  subdivisions.  As  con- 
nected also  with  the  vagus  nerve  both  in  func- 
tion and  by  analogy  of  distribution,  is  the  nerve 
which  we  noticed  so  particularly  in  the  larva, 
the  glossopharyngeal,  (jig.  418,  f,)  which  is 
remarkably  distinct  in  Lucanus,  and  as  in  the 
larva  gives  branches  to  the  under-surface  of  the 
oesophagus.  It  is  remarkable,  also,  that  in  this 
insect  each  root  of  the  vagus  arises  from  a 
ganglion  on  each  side,  situated  below  the  cere- 
bral lobes,  but  closely  connected  to  them,  and 
from  which  ganglion  the  antennal  nerves  (d)  ori- 
ginate, and  a  third  nerve,  which  is  directed 
backwards  among  the  muscles,  but  the  course 


of  which  we  have  not  yet  traced,  but  which 
probably  is  a  compound  nerve  ;  it  appears  to  be 
formed  in  part  by  the  ganglion,  (e,)  and  partly  by 
a  portion  of  the  cerebrum,  which  is  united  to  it. 

Fig.  418. 


Under- surface  of  brain,  fyc.  of  Lncnmis  cervus. 


The  form  which  the  frontal  ganglion  usually 
assumes  is  nearly  triangular,  but  in  some  in- 
stances, as  in  Carabus  monilis,  it  is  elongated, 
oval,  lying  transversely  across  the  pharynx,  but 
in  almost  all  the  insects  we  have  examined,  ex- 
cepting the  Bi/prestida  and  some  of  the  Or- 
thoptera  both  in  the  larva  and  pupa  state,  as 
in  Timarcha,  Mcluc,  Anthophora,  and  Jiumbus, 
whatever  be  its  form,  the  single  nerve  continued 
from  it  has  more  resembled  in  its  distributions 
and  relations  the  vagus  than  the  sympathetic. 
These  are  the  reasons  for  our  continuing  to  de- 
scribe it  as  the  former  rather  than  as  the  latter 
of  these  nerves.  The  fact,  however,  of  its  dis- 
position to  form  ganglia  in  its  course  appears, 
indeed,  as  observed  by  Professor  Miiller,*  to 
assimilate  it  most  in  character  with  the  sympa- 
thetic ;  but  we  conceive  this  fact  to  be  satisfac- 
torily explained  by  the  anatomy  of  these  nerves 
in  Buprestis,  in  which  the  middle  or  recurrent 
nerve,  although  exceedingly  short,  is  very 
large,  and  is  terminated  by  a  ganglion,  as  in 
the  GryUida:,  and  from  which,  in  Buprestis, 
two  small  nerves  are  continued  along  the  oeso- 
phagus, while  the  corresponding  nerves  in 
Gryllus  have  become  approximated  to  those 
from  the  lateral  ganglia,  and  assist  to  form  the 
long  gangliated  nerve  at  the  side  of  the  oesopha- 
gus. The  functions  of  the  vagus  and  sympa- 
thetic in  insects  would  thus  appear  to  be  nearly 
similar,  and  that,  as  is  sometimes  the  case  with 
these  nerves  in  veitebrata,  as  we  have  seen,  for 
example,  in  the  neck  of  the  calf,  the  two  become 
often  closely  approximated  together,  as  noticed 
also  by  Professor  Miiller,  in  the  Myxinoid 
Fishes,  in  which  the  vagus  and  sympathetic 
form  only  one  nerve,  the  chief  portion  of  which 
is  the  vagus,  and  which  is  extended  to  the  anus. 

*  MUllcr's  Archiv,  No.  v.  1837,  Jalircsbrcsht,  p. 
lxxxv.  to  viii. 


960 


INSECTA. 


Organs  of  vision. — The  eyes  of  Insects  are  of 
two  kinds,  simple  and  compound,  and  have 
been  attentively  examined  by  Professor  Miiller, 
Straus  Durckheim,  Duges,  and  others,  from 
whose  admirable  investigations  we  shall  chiefly 
derive  the  following  description.  The  large 
convex  cornea?  which  cover  the  external  surface 
of  the  head  are  divided,  as  we  have  seen,  into 
an  immense  number  of  facets,  generally  of  an 
hexagonal  shape,  or  in  very  rare  instances 
somewhat  quadrangular.  Each  facet,  (fig. 
419,  b,)  or  as  it  has  sometimes  been  called, 
corneule,  is  the  proper  cornea  of  a  distinct  eye, 
and  is  perfectly  transparent.  It  is  somewhat 
broader  at  its  base  or  external  surface  (b,  c) 


A,  section  of  the  eye  of  Melolontha  ( Straus ). 
ii,  section  of  eye  of  Libellula  (Muller  ).  C,  sec- 
tion of  do.  ( Duges ).  b,  the  external  convex 
surfaces  of  the  facet  or  corneule  c,  c,  c;  d,  base 
of  the  corneules ;  a,  the  anterior  chamber  be- 
tween the  corneule  and  iris ;  e,  pupillary  aper- 
ture in  the  iris,  formed  by  the  reflexion  inwards  of 
the  choroid  ;  /,  the  cones  filled  with  the  vitreous 
humour ;  g,  the  nerve  ;  /(,  the  choroid  surround- 
ing the  fibres  of  the  optic  nerve. 

than  at  itsinternal,(rf,)  and  each  one  is  separated 
from  those  by  which  it  is  surrounded  by  the  inter- 
position of  a  layer  of  dark-coloured  pigment,  so 
that  therays  of  light  can  pass  through  it  only  in  a 
direction  converging  to  its  centre.  In  some  in- 
stances, as  in  Lepidoptera,  it  is  convex  both  on 
its  external  and  internal  surface,  or  lens-like, 
but  in  general  is  nearly  plane.  In  the  Libellu- 
lina,  according  to  Duges,  (c,)  it  is  convex  exter- 
nally, and  slightly  concave  internally,  and  it  va- 
ries considerably  in  thickness  in  different  in- 
sects, and  in  different  facets  in  the  same 
compound  cornea.    Immediately  behind  each 


corneule  is  a  layer  of  dark-coloured  pigment, 
(/>,)  which  is  believed  to  be  continuous  with  the 
delicate  pigment  that  is  interposed  between  the 
cornea?.  It  covers  the  whole  of  the  inner  surface 
of  the  cornea,  excepting  only  in  the  centre, 
where  it  is  perforated  by  a  minute  hole  or  pupil- 
lary aperture,  (e,)  to  admit  the  rays  of  light  that 
have  passed  through  the  cornea.  Between  this 
pigment,  which  is  the  curtain  or  iris  of  the  eye, 
and  the  end  of  the  cornea,  Duges  found  a 
space,  («,)  filled  with  an  aqueous  humour.  Be- 
hind the  iris  of  each  cornea  is  a  little  cone- 
shaped  transparent  body,  (_/',)  with  its  apex 
directed  backwards  in  the  axis  of  the  eye.  It  is 
filled  with  a  perfectly  transparent  tenaceous 
fluid,  the  vitreous  humour  of  the  eye,into  which 
the  rays  of  light  received  through  the  cornea 
and  iris  are  admitted,  to  fall  upon  the  retina, 
or  termination  of  the  nerve,  (g,)  at  the  apex  of 
the  cone.  The  length  of  the  cone  differs  greatly 
in  different  insects.  It  is  shortest  in  the  Dip- 
tera,  and  scarcely  exceeds  its  breadth.  In  the 
Coleoptera  and  Lepidoptera  it  is  five  or  six 
times  longer  than  it  is  broad,  and  perhaps  even 
exceeds  this  in  some  of  the  Libellulina.  The 
apex  of  each  cone  is  received  upon  the  extremity 
of  one  of  the  many  thousand  of  fibres  (g) 
which  we  described  as  radiating  from  the  bulb 
of  the  nerve,  immediately  after  it  has  passed 
through  the  optic  foramen.  The  choroid  of 
dark  pigment  that  forms  the  iris  (A)  is  conti- 
nued backwards  over  the  surface  of  the  cone 
and  optic  fibre  to  the  bulb  of  the  optic  nerve, 
thus  completely  insulating  every  individual 
cone  and  fibre  from  those  by  which  they  are 
surrounded.  It  is  in  the  spaces  thus  occupied 
by  the  choroid  that  the  tracheal  vessels  and  cir- 
culatory passages  ramify,  so  that  the  choroid  in 
the  eyes  of  insects,  as  in  those  of  the  verte- 
brata,  is  the  proper  vascular  structure  of  the 
organ.  It  is  subject  to  much  variety  of  colour 
in  different  insects,  being  in  some  nearly  black, 
in  others  dark  blue,  violet,  green,  purple, 
brown,  or  yellow.  In  some  there  are  two  or 
three  layers  of  pigment  of  different  colours. 
The  usual  arrangement  of  these  is  first  a  dark 
coloured  portion  near  the  bulb  of  the  optic 
nerve,  then  a  lighter  colour,  and  lastly,  again,  a 
darker  near  the  cornea?.  According  to  Duges, 
the  base  of  the  cone  is  rounded  where  it  is  co- 
vered by  the  iris,  but  Muller  states  that  this  is 
the  case  only  when  the  cornea  is  devoid  of 
facets  or  corneules,  and  is  perfectly  smooth. 
According  to  the  same  authority,  the  pupillary 
aperture  is  most  distinct  when  the  cones  are 
short,  as  in  Diptera.  This  aperture  was  disco- 
vered by  Muller,  and  also  the  nature  of  the 
cones,  which  had  been  thought  by  Straus- 
Durckheim  to  be  expanded  terminations  of  the 
optic  fibres.  We  have  seen  the  iris  and  pu- 
pillary aperture  very  distinctly  in  the  eye  of 
Pontia  brassicce,  the  white  cabbage  butterfly, 
and  also  in  Sphinx  ligustri  and  Nepa  grandis. 
In  the  two  latter  instances  it  is  of  a  dark  brown, 
or  nearly  black,  and  is  particularly  large  in 
Nepa.  In  Pontia  it  is  yellow,  in  the  centre 
of  which  the  pupil  exhibits  a  glassy  brightness. 
The  manner  in  which  the  extremity  of  the  ner- 
vous fibre  is  connected  with  the  apex  of  the 
cone  has  recently  been  investigated  by  Professor 


INSECT A. 


961 


Wagner,  who  has  found  that  the  fibre  is  pro- 
longed as  a  sheath  over  the  sides  of  the  cone,  of 
which  it  is  supposed  to  form  a  part.  In  this 
manner,  each  of  the  thousands  of  corneules  or 
facets  that  form  die  compound  eye,  transmits 
impressions  from  without  inwards  to  the  optic 
nerve  and  brain,  the  perception  of  each  being- 
confined  to  that  of  the  object  immediately 
before  it,  or  in  a  line  with  its  axis  of  vision. 
On  the  exterior  surface,  between  each  cornea, 
there  are  often  some  very  fine  hairs,  as  on  the 
cornea  of  the  bee,  which  Burmeister  likens  to 
eyelashes,  and  thinks  that  they  assist  to  con- 
fine the  field  of  vision,  as  well  as  protect  the 
cornea.  This  is  the  usual  structure  of  the  eye. 
In  Melolontha,  Straus-Durckheim  describes 
the  filament  of  the  optic  nerve  as  passing 
through  a  second  or  common  choroid,  and  as 
afterwards  uniting  to  form  a  general  retina, 
which  is  connected  with  the  optic  nerve  by 
means  of  short  thick  columns.  The  use  he 
assigns  to  this  structure  is  that  of  intercepting 
tlie  impressions  of  light,  which  might  otherwise 
be  too  powerful. 

The  ocelli,  or  simple  eyes  of  insects,  re- 
semble those  of  Arachnidans,*  in  being 
formed  of  a  very  convex,  smooth,  single  cornea, 
benea<th  which  is  a  spherical  crystalline  lens, 
resting  upon  the  plano-convex  surface  .of 
the  expanded  vitreous  humour,  the  analogue 
of  the  transparent  cones  of  the  compound  .eyes. 
The  vitreous  humour,  as  in  Arachnidans,  is 
inore  convex  on  its  posterior  or  under  surface, 
and  is  contained  in  the  expanded  retina  at  the 
termination  of  the  optic  tubercle,  upon  which 
each  ocellus  is  situated,  the  exterior  surface  of 
the  retina  being  covered  by  a  dark  pigmentous 
membrane,  the  proper  choroid,  which  is  re- 
flected inwards  upon  the  anterior  portion  of  the 
-vitreous  humour,  to  form  the  iris  and  pupillary 
aperture.  Midler,  who  discovered  this  struc- 
ture in  the  stemmata  of  insects  as  well  as 
Arachnidans,  concludes  that  the  function  of 
the  simple  eyes  is  confined  exclusively  to  the 
perception  of  near  objects,  and  that  of  the 
compound  eyes  to  more  distant  ones,  and  has 
given  many  facts  in  illustration  of  this  opinion, 
and  which  shew  that  in  many  instances,  parti- 
cularly in  the  Orlhoptera,  the  ocelli  are  so 
placed  as  to  'render  it  almost  impossible  that 
they  can  be  used  except  in  viewing  near  ob- 
jects. In  all  inseets  that  undergo  a  true  me- 
tamorphosis ocelli  constitute  the  only  organs 
of  vision  in  the  larva  state.  They  vary  in 
number  in  different  species;  thus  in  the  active 
larvae  of  Hymenoptera,  as  in  Athalia,  there  are 
only  two,  one  on  each  side  of  the  head  ;  this  is 
also  the  number  in  some  of  the  carnivorous 
Coleoptera.  But  in  others  there  are  six  on 
each  side,  as  in  Dyticns,  and  the  same  number 
is  found  in  most  of  the  Lepidoptera.  We  have 
recently  detected  what  we  believe  to  be  organs 
of  vision  in  a  Dipterous  larva,  OZsirusovis,  (jig. 
360,)  which  resides  in  the  frontal  sinuses  of  the 
sheep,  into  which,  probably,  a  small  amount  of 
light  may  enter  through  the  nostrils.  These 
consist  of  two  brown  spots  on  each  side  of  the 

*  S*e  Akaciinida,  voU  i,  /ig.  94. 

VOL.  11. 


head,  (h  2,)  placed  at  a  little  distance  from  each 
other,  immediately  beneath  a  convex  and  very 
transparent  part  of  the  tegument,  which  resem- 
bles a  true  cornea.  This  is  the  most  simple 
form  of  eye  we  have  yet  met  with  in  insects, 
and  seems  to  be  merely  for  the  perception  of 
light,  like  the  eyes  of  the  Medusa  discovered 
by  Ehrenberg,  but  perhaps  more  organized,  as 
the  spots  observed  appear  to  be  a  choroid, 
which  is  seen  to  descend  until  it  is  lost  in  the 
substance  of  the  part.  No  compound  eyes 
exist  in  any  larva  that  undergoes  a  complete 
metamorphosis.  In  those  which  undergo  an 
incomplete  one,  as  in  the  Orthoptera,  the 
facets  of  the  eye  are  larger  and  more  convex 
than  in  the  perfect  state,  and  the  true  ocelli 
which  exist  in  the  perfect  state  are  not  deve- 
loped. In  the  larva  and  pupa  of  lieduvitis 
personatus  there  is  an  aggregation  of  simple 
eyes,  like  those  of  Myriapoda,  very  much 
larger  and  more  convex  than  the  facets  of  the 
compound  eye  of  the  perfect  insect.  Simple 
eyes  exist  in  the  perfect  state  in  the  Hymenop- 
tera, Orthoptera,  Ilemiptera,  Neuroptera,  Tri- 
choptera,  Homoptera,  and  in  some  of  the  Lepi- 
doptera and  Hornaloptera,  and  in  a  very  few 
instances  in  the  Coleoptera. 

Organ  of  hearing. — Every  naturalist  who  has 
at  all  attended  to  the  consideration  of  the  faculty 
of  hearing  in  insects,  is  doubtless  convinced 
that  these  little  creatures  are  not  merely  affected 
by  sounds,  but  that  hearing  constitutes  one  of 
their  chief  senses;  yet  it  is  hitherto  undecided 
what  organ  or  part  of  the  animal  is  the  seat  of 
this  function.  Wehaveabove  stated  ouropinion, 
(p.  892,)  with  many  others,  that  it  resides  in  the 
antennae,  which,  if  this  be  not  confirmed,  is  at 
any  rate  supported  by  the  experiments  hitherto 
made  upon  these  organs,  and  also  by  their 
structure  and  the  manner  in  which  they  are 
employed  by  the  insect.  The  nerves  distributed 
to  the  antennae  have  often  a  ganglion  at  their 
base,  and  are  divided  into  many  branches  almost 
immediately  after  they  have  entered  the  organ, 
so  that  at  present  no  difference  has  been  detected 
between  the  distribution  of  the  nerves  to  these 
parts  and  those  to  other  structures.  They  cer- 
tainly exhibit  no  bulbed  extremity  like  the  audi- 
tory nerves  of  the  higher  animals,  while  the 
manner  in  which  the  antennae  are  employed 
by  many  insects  has  induced  some  observers  to 
believe  that  they  are  simply  organs  of  touch. 
This  cannot  be  their  primary  function,  since,  as 
formerly  remarked,  they  are  too  short  to  be 
employed  as  tactile  organs  by  many  insects, 
while  their  structure,  we  conceive,  is  in  every 
instance  adapted  for  hearing  or  perceiving  the 
pulsations  of  the  atmosphere. 

Organs  of  touch. — The  organs  which  appear 
specially  adapted  to  the  exercise  of  this  function 
are  the  palpi,  which  derive  their  nerves,  as 
above  shown,  from  the  medulla  oblongata. 
These  organs  are  employed  in  a  similar  manner 
by  all  insects  to  touch  the  food.  It  is  with 
these  that  the  insect,  as  it  were,  feels  about 
when  it  is  in  search  of  nourishment,  and  hence 
these  may  be  regarded  as  the  proper  tactile 
organs.  It  has  sometimes  been  supposed  that 
they  are  also  concerned  in  the  function  of  taste. 

Z  it 


962 


INSECTA. 


but  this  opinion  is  not  borne  out  by  the  physi- 
cal condition  of  these  parts,  which,  in  almost 
every  instance,  is  unadapted  for  such  purpose, 
being  covered  by  a  hard  bony  exterior.  In  some 
instances  the  extremities  of  the  palpi  are  covered 
with  a  soft  bulb-like  extremity,  while  in  many 
others  which  are  known  to  perceive  the  quality  of 
food  very  quickly,  they  yet  have  the  extremities 
of  the  part  covered  with  a  hard  imperforate 
structure. 

As  to  the  seat  of  the  organ  of  smell  we  are 
quite  as  ignorant  of  it  as  of  that  of  taste.  Cuvier 
and  some  others  have  imagined  that  the  faculty 
of  smelling  resides  in  the  mucous  lining  of  the 
spiracles  at  the  sides  of  the  body,  but  ex- 
periment has  still  left  the  question  undecided. 
From  the  few  observations  we  have  been  able 
to  make  on  this  subject  we  certainly  have 
been  led  to  conclude  that  it  is  confined  to 
some  part  of  the  head,  and  not  seated  at  the 
different  spiracles. 

Tlie  development  of  the,  brain  and  nervous 
cvrd  during  the  metamorphoses  exhibits  some 
of  the  most  curious  alterations  of  form  that 
take  place  in  any  structure.  These  changes 
were  first  traced  by  Ilerold  in  the  great 
cabbage-butterfly,  Pontia  Brassiccc,  and  sub- 
sequently by  the  writer  of  the  present  article 
in  the  privet  hawk-moth,  Sphinx  ligustri* 
and  also  in  the  nettle-butterfly,  Vanessa  urtiece. 
We  have  seen  from  the  foregoing  details,  that 
during  the  last  period  of  the  larva  slate,  at 
which  time  the  insect  has  been  most  frequently 
examined,  certain  changes  of  form  have  al- 
ready taken  place  in  different  parts  of  the 
cord,  so  that  these  changes  of  structure,  which 
at  first  appear  to  be  effected  so  rapidly  at  a 
cerlain  period,  have  been  for  a  long  time  in 
progress.  We  have  seen  that,  besides  the  la- 
teral approximation  of  the  cords,  the  first 
change  consists  in  an  union  of  the  eleventh  and 
twelfth  ganglia,  the  latter  one  being  carried 
forwards ;  and  that,  although  a  complete  co- 
alescence of  these  has  sometimes  taken  place  so 
early  as  a  day  or  two  before  the  caterpillar  casts 
its  last  skin,  yet  even  at  that  period  the  cere- 
bral ganglia  have  scarcely  become  united  above 
the  oesophagus.  At  a  still  earlier  period,  when 
the  larva  has  not  yet  cast  its  third  skin,  we  have 
found  the  eleventh  ganglia  perfectly  distinct 
from  the  twelfth,  with  a  small  intervening  por- 
tion of  cord,  and  the  cerebral  ganglia  scarcely 
touching  each  other  above  the  oesophagus,  and 
the  distance,  or  extent  of  cord,  between  the 
fourth  and  fifth  ganglia  much  greater  than  at 
the  subsequent  period  when  the  insect  is  pre- 
paring to  change  into  the  pupa  state. 

We  had  commenced  our  observations  on 
these  changes  in  the  nervous  system  on  the 
larva  and  pupa  of  the  Sphinx,  when  it  appeared 
desirable  also  for  various  reasons  to  make 
similar  observations  on  an  insect  in  which 
these  changes  were  commenced  and  completed 
within  a  short  and  known  period,  and  for  that 
purpose  selected  the  commonest  of  our  native 
insects,  the  nettle-butterfly,  Vanessa  urtiete, 
which  undergoes  its  changes  within  fourteen 
days.    The  Sphinx  remains  in  the  pupa  state 

*  Phil.  Trans,  pt.  2.  1832,  1834. 


during  the  whole  winter,  by  which  we  are 
enabled  to  compare  the  same  changes  in  an 
insect  in  which  they  have  taken  place  slowly 
with  those  in  another  in  which  they  have  been 
completed  more  rapidly,  and  the  extent  of 
development  at  the  completion  of  both  is  in- 
variably found  to  be  the  same.  In  order  to 
observe  these  changes  correctly,  a  large  number 
of  the  caterpillars  was  collected  at  the  period 
when  they  have  ceased  to  feed,  and  are  about 
to  suspend  themselves  to  undergo  their  trans- 
formation, and  the  moment  was  carefully 
watched  both  when  they  suspended  them- 
selves preparatory  to  undergoing  their  meta- 
morphoses, and  also  when  they  were  in  the  act 
of  assuming  the  pupa  state.  By  these  means 
a  sufficient  number  of  specimens  was  obtained, 
and  their  periods  of  transformation  accurately 
known.  Previously  to  commencing  these  ob- 
servations on  the  nettle-butterfly,  we  had  noticed 
in  the  pupa  of  the  Sphinx  a  very  singular  ap- 
pearance at  the  base  of  each  optic  nerve,  which 
on  close  inspection  was  found  to  be  a  dark- 
coloured  membrane  of  an  ovate  form,  from 
which  is  developed  the  choroid  of  the  future 
eye.  The  existence  of  this  spot  is  exceedingly 
interesting  as  illustrating  the  manner  in  which 
the  complicated  organ  of  vision  in  the  perfect 
insect  is  developed.  This  spot,  which  at  first 
appears  like  a  dark  gelatiniform  deposit,  con- 
sists of  five  black  tubercular  elevations,  having 
the  appearance  of  so  many  parts  of  a  corru- 
gated membrane,  and  exists  before  the  larva 
has  changed  into  a  pupa.  We  have  never  found 
it  absent  in  any  insect  that  is  about  to  change, 
but  have  not  observed  it  until  the  insect  has 
ceased  to  feed. 

Two  hours  after  the  larva  of  Vanessa  urticic 
has  suspended  itself  to  undergo  its  transform- 
ation, and  in  which  state  it  remains  from  six  to 
eight,  ten,  or  even  twenty-four  hours,  according 
to  the  strength  of  the  individual  and  other  cir- 
cumstances, before  it  throws  off  its  last  larva 
skin  a  considerable  alteration  has  already  taken 
place  in  the  body  of  the  larva ;  the  cerebral 
lobes  are  still  distinct  from  each  other,  but  are  a 
little  altered  in  form,  although  not  yet  enlarged. 
When  viewed  from  above  they  exhibit  a  pear- 
shaped  appearance,  the  anterior  part  of  the 
lateral  surface  of  each  being  elongated  to  give 
origin  to  the  antennal  and  optic  nerves.  At 
the  base  of  the  latter,  even  at  this  early  period, 
the  dark  rudimentary  choroid  is  very  distinct. 
The  sub-cesophageal  ganglion  is  enlarged  to 
nearly  twice  its  original  size,  and  the  crura  are 
much  enlarged  and  shortened,  as  well  as  the 
cords  that  connect  the  second,  third,  fourth,  and 
fifth  ganglia.  The  last  two  are  separated  only 
by  a  short  interval.  The  fifth,  sixth,  and  seventh 
ganglia  are  drawn  closer  together,  the  cords 
between  them  disposed  in  an  irregular  ziz-zag 
manner,  and  the  longitudinal  direction  of  the 
ganglia  is  in  consequence  altered.  The  ganglia 
from  the  seventh  to  the  terminal  one  remain  as 
in  the  active  larva. 

By  unremittingly  watching  a  number  of 
larva  through  all  their  preparatory  stages,  we 
are  enabled  to  judge  within  a  very  short  period 
when  the  transformation  will  take  place.  A 
little  while  before  the  old  skin  is  thrown  off 


INSECTA. 


903 


Fig.  420. 

1  2  3 


Full-grown 
larva.  (Newport,  Ph.  Trans.) 


there  is  great  excitement  throughout  the  body  of 
the  insect.  About  half-an-hour  (Jig.  419,  2) 
before  this  occurs  the  alary  nerves  and  the 
cerebral,  second,  third,  fourth,  and  fifth  ganglia 
are  slightly  enlarged,  and  the  medulla  or  first 
sub-oesophageal  ganglion  very  considerably.  The 
cords  that  extend  between  them  diverge  much 
from  each  other,  while  those  between  the  fifth, 
sixth, and  seventh  ganglia,  are  disposed  in  a  more 
zig-zag  direction  than  in  other  parts  of  the  body. 

Immediately  after  the  insect  has  entered  the 
pupa  state  (3),  all  the  ganglia  are  brought 
closer  together  in  consequence  of  the  cords 
being  disposed  more  irregularly  than  at  any 
other  period,  which  has  been  occasioned  by  the 
shortening  that  has  taken  place  in  every  seg- 
ment, by  which  the  cords  are  rendered  too  long 
to  lie  in  a  direct  line.  The  cords  which  con- 
nect the  first  five  ganglia  are  slightly  increased 
in  size,  and  the  fourth  and  fifth  and  their  inter- 
vening cords,  in  which  the  first  great  changes 
commence,  are  often  nearer  together,  and  have 
become  more  united  at  this  period  of  the  trans- 
formation, in  some  specimens,  than  in  others 
at  five  or  six  hours  later.  This  is  in  accord- 
ance with  what  we  have  observed  in  the  Sphinx 
ligustri,  in  which  the  precise  period  when  the 
union  of  ganglia  takes  place  cannot  positively 
be  ascertained  in  consequence  of  its  differing 
in  different  specimens  according  to  the  vigour 
of  the  insect,  or  to  the  temperature  of  the 
season  at  the  time  of  changing. 

One  hour  after  (fig.  421,  4)  the  transform- 


Fig.  421. 

4  5  6 


One  hour  after    Twelve  hours.  Eighteen  hours, 
changing. 

ation  the  cerebral  ganglia  are  found  to  be  more 
closely  united,  the  antennal  nerves  more  dis- 
tinct, and  the  optic  nerves  more  enlarged  at 
their  base.  The  fourth  and  fifth  ganglia  are 
approaching  each  other,  and  the  cords  are  en- 
larged at  their  connexion  with  the  latter,  the 
anterior  part  of  which  has  become  less  dis- 
tinct, and  seems  about  to  coalesce  with  them. 
The  distance  between  the  remaining  ganglia  is 
also  reduced,  and  the  investing  membrane,  or 
exterior  surface  of  the  cord  exhibits  a  corrugated 
appearance  as  if  in  the  act  of  becoming 
shortened.  We  have  seen  in  the  account  pre- 
viously given  of  the  nervous  system  in  the 
larva  of  the  Sphinx,  that  besides  the  longi- 
tudinal cords  and  ganglia,  and  the  nerves  dis- 
tributed from  them,  there  are  also  the  trans- 
verse nerves.  There  are  like  nerves  in  Papilio 
urtica,  and  which  are  distributed  to  the  same 
parts  as  in  the  Sphinx.  They  commence  be- 
hind the  first  sub-oesophageal  ganglion  or  me- 
dulla, where  the  first  of  them  pass  directly  out- 
wards in  the  course  of  the  tracheae  that  come 
from  the  first  spiracle,  and  distribute  and  give 
some  branches  to  the  surface  of  the  medulla 
and  its  nerves,  and  some  also  to  the  second 
ganglion  (d),  while  the  main  branch  passes 
along  in  the  direction  of  the  muscles  of  the 
back  part  of  the  head.  Behind  the  second 
ganglion  branches  of  tracheal  vessels,  and 
also  a  nerve  from  the  transverse  plexus,  are  given 
to  the  great  alary  nerve  (  /  )  that  arises  in  this 
insect  singly  from  the  cord  between  the  second 
and  third  ganglion,  and  not,  as  in  the  Sphinx, 
one  portion  from  the  cord  and  another  from  the 
ganglion  posterior  to  it.  From  the  cord  be- 
tween the  third  and  fourth  ganglion  arises  the 
second  alary  nerve  (i),  which  like  the  preceding 
arises  singly  from  the  cord,  but  receives  also  a 

•  1832. 

3  R  2 


964 


INSECTA. 


branch  from  the  transverse  nerves  posterior  to 
the  third  ganglion.  A  plexus  of  these  trans- 
verse nerves  exists,  as  in  the  Sphinx,  anterior  to 
each  ganglion  (o,  o),  to  the  nerves  of  which 
they  give  a  single  filament  near  their  base,  and 
another  when  arrived  near  the  spiracle,  while 
their  main  branches,  as  in  the  latter  insect,  are 
distributed  separately  among  the  tracheae  and 
muscles.  Those  branches  of  transverse  nerves 
which  pass  off  laterally  from  between  the 
fourth,  fifth,  sixth,  and  seventh  ganglia,  become 
approximated  to  the  nerves  from  those  ganglia, 
and  in  the  development  of  the  insect  at  this 
period  afford  an  example  of  the  commence- 
ment of  the  interesting  fact  of  the  formation  of 
nervous  trunks  by  the  approximation  of  many 
fibres.  The  transverse  nerves  anterior  to  the  fifth 
ganglion  (5,  o)  are  those  that  first  become  united 
to  the  moto-sensitive  nerves  from  the  gangliated 
cord,  and  at  this  period  of  the  transformation 
the  two  are  beginning  to  become  united. 

Seven  hours  after  the  insect  has  become 
a  pupa  there  is  a  greater  enlargement  of  the 
cerebral  ganglia,  optic  nerves,  and  ganglia  and 
cords  of  the  future  thoracic  segments.  The 
fourth  and  fifth  have  advanced  closer  together, 
and  the  cord  between  them  has  become  so 
much  shortened,  enlarged  in  diameter,  and  ap- 
proximated to  its  fellow,  as  to  resemble  in 
shape  a  separate  elongated  ganglion,  and 
strongly  to  support  the  opinion  formerly  ad- 
vanced by  us*  of  the  actual  transmission  for- 
wards of  the  nervous  matter  within  the  in- 
vesting membranes  of  the  cord,  rather  than 
that  of  its  deposition  and  accumulation  at 
certain  parts  through  the  agency  of  the  nutri- 
tive or  vascular  system.  At  this  period  also  all 
the  remaining  ganglia  have  become  slightly 
enlarged,  and  the  distance  between  the  fifth  and 
sixth  is  much  diminished,  and  the  cords  just 
anterior  to  each  ganglion  are  also  slightly  en- 
larged and  are  disposed  with  less  irregularity 
than  at  a  previous  period.  At  this  stage  of  the 
transformation  the  transverse  nerves  (o  o)  also 
are  beginning  to  assume  their  temporary  gan- 
glionic appearance,  and  the  terminal  nerves 
from  the  caudal  ganglion  are  enlarged  to  sup- 
ply the  developing  organs  of* generation. 

At  twelve  hours  (5)  the  fifth  ganglion  has 
almost  completely  coalesced  with  the  cord  and 
fourth,  and  has  assumed  an  elongated  trian- 
gular appearance,  and  the  transverse  nerves, 
which  at  seven  hours  were  beginning  to  be 
united  to  the  nerves  from  this  ganglion,  have 
now  so  completely  joined  them  as  almost  en- 
tirely to  have  disappeared,  there  being  in 
some  instances  only  a  triangular  elevation  upon 
the  gangliated  cord,  with  a  portion  of  nerve 
passing  outwards  to  indicate  their  previous 
separation,  thus  affording  a  further  proof  of 
the  adhesion  of  contiguous  parts,  and  of  the 
manner  in  which  nervous  trunks  are  formed. 

At  eighteen  hours  (6)  the  whole  of  the  gan- 
glia, cords,  and  nerves  have  become  more  en- 
larged, particularly  those  of  the  wings,  and  the 
transverse  nerves,  although  continuing  separate, 
give  filaments  to  the  nerves  from  the  ganglia, 
and  themselves  exhibit  at  their  point  of  di- 
vision more  the  appearance  of  ganglia;  while 
the  fourth  and  fifth  ganglia  of  the  cords  have 


now  so  completely  united  as  to  appear  like  an 
irregular  elongated  mass.  The  abdominal  por- 
tion of  the  cord  is  now  extended  in  a  more 
direct  line  in  the  body,  and  anterior  to  each 
ganglion  is  still  enlarged. 

Fig.  422. 

7  8 


Twenty-four  hours, 


Thirty-six  lumrs. 


At  twenty-four  hours  (Jig  422,  7)  the  fourth 
and  fifth  ganglia  are  completely  united,  the 
fifth  being  larger  than  the  fourth.  The  cords 
before  the  sixth  are  enlarged,  as  also  are  the 
transverse  nerves  of  the  thorax,  which  seem  to 
keep  pace  with  or  rather  to  precede  the  deve- 
lopment of  the  respiratory  organs. 

At  thirty-six  hours  (8)  the  optic  nerves  have 
attained  a  size  almost  equal  to  that  of  the 
cerebral  ganglia,  and  after  this  period  become 
very  little  larger.  During  the  preceding  stages 
of  the  transformation  the  minute  black  patch 
observed  at  their  base  has  been  gradually  more 
and  more  expanded,  and  carried  forwards  from 
the  posterior  superior  part  of  each  lobe  to  its 
lateral  part,  which  at  this  period  it  is  begin- 
ning to  cover,  while  the  optic  nerves  appear  as 
if  developing  from  within  outwards,  and  have 
a  somewhat  pear-shaped  form.  The  first  sub- 
cesophageal  ganglion, ormedulla,nowforms  with 
the  cerebral  ones  a  complete  ring  around  the 
oesophagus,  the  crura  having  almost  disap- 
peared. The  fifth  ganglion  has  decreased  in 
size  and  is  now  smaller  than  the  fourth,  while, 
in  some  specimens,  the  nerves  that -arise  now 
come  from  the  cords  immediately  behind  it, 
thus  giving  a  further  proof  that  the  nervous 
substance  of  the  ganglion  has  been  transmitted 
forwards.  The  sixth  ganglion,  which  at 
twenty-four  hours  was  much  reduced  in  size, 
has  entirely  disappeared,  but  the  nerves  that 
belonged  to  it  remain  and  are  now  derived 
from  the  cord,  very  near  to  those  which  be- 
longed to  the  fifth  ganglion,  thus  further 
proving,  as  formerly  remarked  by  us,*  that  the 
nervous  substance  has  been  transmitted  for- 
wards along  the  cord.  This  view  of  the 
manner  in  which  these  changes  in  the  form  and 

*  Phil.  Trans.  1834. 


INSECTA. 


965 


size  of  different  parts  of  the  nervous  system  is 
effected  is  in  full  accordance  with  the  recently 
developed  facts  of  Ehrenberg  and  others  re- 
specting the  tubular  nature  of  the  primary 
nervous  fibres. 

At forty-eight  hours,  (Jig.  423, 9)  the  whole  of 
the  cords  have  regained  the  longitudinal  direc- 
tion, and  the  seventh  ganglion,  which  had  begun 
to  be  decreased  in  size  at  the  last  period,  has 
now  also  entirely  disappeared,  and  its  nerves, 
like  those  of  the  fifth  and  sixth,  come  from  the 
cord,  while  the  ganglia  of  the  thorax  are  ac- 
quiring a  great  size. 


Fig.  423. 


Forty-eight  hours.  Fifty-eight  hours. 

At  fifty-eight  hours  (10)  a  further  change 
has  been  effected.  The  second  and  third  tho- 
racic ganglia  have  united,  and  the  double  gan- 
glion thus  formed  is  only  separated  from  the 
Jarger  thoracic  mass  composed  of  the  fourth, 
fifth,  and  part  of  the  sixth  ganglia,  by  the  short 
but  greatly  enlarged  cords  which  pass,  as  before 
noticed,  on  each  side  of  the  central  attachment 
of  the  muscles.  The  transverse  plexus  are 
united  with  the  nerves  to  the  wings,  and  the 
whole  of  these  gangliated  portions  of  cord  have 
been  carried  forwards,  and  now  occupy  the 
middle  portion  of  the  immensely  enlarged 
meso-thorax.  The  optic  and  antennal  nerves 
have  nearly  attained  their  full  development, 
and  those  numerous  and  most  intricate  plexus 
of  nerves  in  the  three  thoracic  segments  of 
the  larva  form  only  a  few  trunks,  which  can 
hardly  be  recognized  as  the  same  structures. 
The  arrangement  of  the  whole  nervous  system 
is  now  nearly  as  it  exists  in  the  perfect  insect. 
The  whole  of  these  important  changes  are  thus 
seen  to  take  place  within  the  first  three  days 
after  the  insect  has  undergone  its  metamor- 
phosis; and  they  precede  those  of  the  alimentary 
canal,  generative  system,  and  other  organs, 
which  are  still  very  far  from  being  completed, 
and  indeed,  as  compared  with  the  nervous  sys- 
tem, have  made  but  little  progress. 

Such  is  the  rapidity  of  these  changes,  as  ob- 
served by  us  in  June,  1832,  in  a  species  that 
usually  undergoes  its  metamorphosis  from  the 
larva  to  the  perfect  state  in  about  fourteen  days. 
On  repeating  our  observation  on  the  same  insect 
in  the  following  August,  when,  from  the  in- 
creased temperature  of  the  season,  the  whole  of 


the  changes  in  the  body  were  completed  in 
about  eight  days,  we  did  not  observe  that  these 
had  become  much  accelerated,  although  the 
changes  in  the  other  structures  were  hastened. 
The  whole  of  these  phenomena  are  induced  by 
an  alteration  which  takes  place  in  the  external 
tegument,  and  the  permanent  contraction  of 
the  longitudinal  and  diagonal  muscles  of  the 
body,  by  means  of  which  the  anterior  margin 
of  one  segment  is  drawn  beneath  the  posterior 
of  that  which  immediately  precedes  it.  This 
is  carried  to  a  greater  or  less  extent  in  the  diffe- 
rent segments,  and  the  nervous  cord  being  in 
consequence  rendered  too  long  to  lie  in  a  direct 
line,  a  disposition  is  thus  induced  in  its  va- 
rious parts  to  coalesce. 

Organs  of  Nutrition.— -The  chief  organs  of 
nutrition  in  insects,  the  alimentary  canal  and 
its  appendages,  assume  a  variety  of  forms  in 
the  different  classes,  and  undergo  changes  al- 
most as  remarkable  as  those  of  the  nervous 
system.  From  being  scarcely  more  than  a 
simple  elongated  tube,  with  a  few  slight  en- 
largements in  its  course,  as  in  some  of  the 
apodal  Hymenoptera,  the  alimentary  canal  be- 
comes in  the  perfect  individual  a  long  convo- 
luted organ,  thick,  muscular,  and  divided  into 
several  compartments,  each  of  which  is  adapted 
to  a  peculiar  function,  but  subservient  to  the 
more  general  one  of  assimilating  the  food  re- 
ceived, into  one  homogeneous  material,  fitted 
for  the  nourishment  of  the  whole  body.  But 
whatever  be  its  particular  form,  the  alimentary 
canal  may  be  regarded  as  composed  of  three 
distinct  coats  or  tissues,  which  we  shall  dis- 
tinguish as  the  external  or peritonaal,  the  middle 
or  muscular,  and  the  internal  or  mucous. 

The  peritonaal  coat,  or  layer,  is  an  exceed- 
ingly transparent,  white,  shining,  and  delicate 
membrane,  and  is  observed  only  with  great 
difficulty.  It  covers  the  outer  surface  of  the 
muscular  coat  throughout  the  whole  course  of 
the  canal,  and,  as  we  are  strongly  induced  to 
believe,  although  we  have  not  positively  ascer- 
tained it,  is  continuous  with  and  reflected 
along  the  tracheal  vessels  that  ramify  on  the 
stomach,  and  forms  their  external  covering. 
We  have  never  been  able  to  detach  it  from  the 
muscular  coat,  which  it  completely  invests, 
and  to  which  it  closely  adheres,  but  we  have 
seen  it  most  distinctly  in  recently  killed  insects, 
more  particularly  in  the  Apidtc,  as  in  Antho- 
phora  return,  when  the  canal  has  been  removed 
from  the  body  and  viewed  by  transmitted  light. 
It  is  then  seen  most  distinctly  extending  along 
the  sides  of  the  canal,  directly  across  the 
angles  formed  by  the  contraction  of  some  part 
of  the  muscular  coat,  where  this  is  thrown  into 
folds  or  depressions. 

The  muscular,  or  middle  coat,  is  very  strongly 
marked.  It  is  composed  of  transverse  and  longi- 
tudinal fibres,  interlaced  with  each  other,  and  also 
of  a  series  of  oblique  fibres,  which,  as  shewn  by 
Lyonet  in  the  Cossus,  sometimes  in  part  form  the 
retractoresventriculi  muscles,  that  assist  to  retain 
the  canal  in  its  proper  position  in  the  body,  and 
connect  it  with  the  whole  muscular  system. 
Burmeister  states,*  that  distinct  transverse  and 

*  Op.  cit.  (trans,)  p.  121. 


966 


INSECTA. 


longitudinal  vessels  can  be  discovered  in  the 
muscular  coat,  but  we  have  never  been  able  to 
observe  them.  The  muscular  coat  is  most 
distinct  in  the  proventriculus  or  gizzard,  the 
ventrkulus  or  digestive  stomach,  and  the  colon, 
but  may  be  traced  throughout  the  whole  of  the 
canal.  The  longitudinal  and  transverse  fibres 
are  each  developed  to  a  greater  or  less  extent  in 
different  insects ;  in  some,  more  especially  in 
the  larva  state,  as  in  the  Lepidoptera,  the  longi- 
tudinal fibres  form  six  strong  bands,  arranged 
at  equal  distances  around  the  canal,  and  ex- 
tended from  one  extremity  of  it  to  the  other, 
more  or  less  developed  in  different  parts  of 
their  course ;  while  in  other  instances,  more 
particularly  in  the  perfect  state,  the  circular 
fibres  are  most  developed,  as  in  the  Hymenop- 
tera,  in  which  the  longitudinal  fibres  on  the 
stomach  are  scarcely  observable. 

The  mucous,  or  internal  coat,  analogous  to  the 
mucous  coat  in  the  higher  animals,  is  divided 
into  two  layers,  each  of  which  has  been  consi- 
dered as  a  distinct  structure  by  different  anato- 
mists.   The  most  internal  of  these  layers  forms 
the  proper  lining  of  the  alimentary  canal,  and 
is  a  smooth  soft  membrane,  particularly  distinct 
in  the  upper  part  of  the  canal,  but  less  so  in 
the  lower.    It  is  continuous  with  the  lining  of 
the  mouth  and  pharynx,  and  is  often  plaited 
or  folded  longitudinally,  but  seldom  trans- 
versely, excepting  where  it  covers  a  fold  of  the 
other  structures  to  form  a  valve  at  any  part  of 
the  canal.    It  is  this  membrane  which  is  often 
solidified  at  the  upper  part  of  the  canal,  and 
developed  into  rows  of  strong  horny  teeth,  as 
in  the  Orthoptera  and  some  carnivorous  Co- 
leoptera,  or  is  covered  entirely  with  exceedingly 
minute  ones  over  its  whole  surface,  as  is  parti- 
cularly the  case  in  Gryllus  migrutorius.  In 
some  instances  it  is  very  loosely  attached,  and 
forms,  as  it  were,  a  soft  and  easily  separated 
lining  to  the  canal,  more  particularly  in  the 
venlriculus,  as  in  the  MeToe  and  some  other 
genera.    The  other  layer  of  this  coal,  which  has 
been  regarded  as  a  distinct  structure,  is  situ- 
ated between  the  proper  mucous  or  lining 
membrane  and  the  muscular  coat.    It  is  this 
layer  which  is  considered  by  Straus  as  the  pro- 
per skin  or  lining.    It  is  usually  thin,  floccu- 
lent,  and  frequently  without  indications  of  dis- 
tinct texture,  although  it  is  occasionally  found 
to  possess  it,  as  shewn  by  Burmeister  in  Hi/dro- 
philtis.    Straus  has  sometimes  observed  horny 
prominences  in  it,  which  he  considers  of  a 
glandular  nature.    The  markings  in  Hydrophi- 
lus  appear  to  be  of  the  same  description.  liam- 
dohr  mistook  this  layer  for  a  layer  of  transuded 
chyle ;  Straus  and  Burmeister  regard  it  as  per- 
fectly distinct  from  the  mucous  coat,  and  Pro- 
fessor Grant  in  alluding  to  it  seems  to  regard  it 
as  a  loose  intermediate  cellular  tissue.*  This 
is  our  own  opinion  also  of  its  nature,  because 
we  have  been  unable  to  trace  it  as  a  distinct 
layer  throughout  the  whole  of  the  canal.  It 
exists  most  distinct  in  the  ventriculitis',  but  we 
have  not  been  able  to  trace  it  in  the  colon,  ex- 
cepting, perhaps,  in  the  Lepidoptera,  in  which 
it  appears  to  be  what  we  have  regarded  as  an 

*  Outlines  of  Comparative  Anatomy,  p.  349. 


adipose  coal.  The  inner  or  true  mucous  layer 
is  very  distinct,  and  in  some,  as  in  Cerura  vi- 
nula,  is  covered  with  minute  rounded  glands. 

The  alimentary  canal  is  retained  in  its 
position  in  the  body  partly  by  means  of  the  re- 
tractores  ventriculi,  which  we  have  observed 
most  distinctly  in  the  larva?  of  Diptera,  as  in 
Eristalis  tenax,  as  well  as  in  Lepidoptera  and 
others  ;  but  more  especially  by  means  of  rami- 
fications of  the  tracheal  vessels,  which  pass 
from  the  great  longitudinal  trachea?,  near  the 
spiracles,  and  are  distributed  in  profusion  over 
the  alimentary  canal  throughout  its  whole 
course.  Burmeister  says  that  a  peritonaeum, 
such  as  retains  the  intestines  in  their  place  in 
the  higher  animals,  does  not  exist  in  insects. 
This,  however,  as  we  have  above  shewn,  is  not 
strictly  the  case,  since  a  peritonoeum  certainly 
exists  as  a  coat  of  the  alimentary  canal,  al- 
though we  have  never  been  able  to  observe  it 
forming,  as  stated  by  Professor  Grant,*  "a 
distinct  thin  mesentery,"  connecting  the  con- 
volutions of  the  intestines  with  the  interior  of 
the  abdominal  segments. 

The  parts  of  the  alimentary  canal  are  the 
mouth  and  pharynx,  the  (Esophagus,  (jig-  424,  h,) 
and,  in  the  Lepidoptera,  (jig.  430,  t,)  Ilymen- 
optera,  and  Diptera,  the  crop,  which  is  a  dila- 
tation of  the  oesophagus  carried  to  so  great  an 
extent  as  to  form  a  distinct  appendicular  cavity  ; 
the  proventriculus  or  gizzard  (t),  the  venlri- 
culus or  proper  digestive  stomach  (/c),  the 
ilium  or  short  intestine  (/),  and  the  colon 
(m,  n)  and  rectum  (p).  These  exist  in  the 
most  developed  form  of  the  canal,  but  not  in- 
variably or  to  the  same  extent  in  every  insect. 
The  crop  is  frequently  absent,  as  are  also  the 
proventriculus  and  the  rectum,  but  the  remain- 
ing parts  are  almost  constantly  present.  Be- 
sides these  as  forming  parts  of  the  digestive 
apparatus,  there  are  the  appendicular  struc- 
tures, consisting  of  the  salivary  glands  (a),  the 
gastric  (a,b,c),  and  the  so-called  biliary  (p) 
and  the  anal  vessels  (s).  Of  these  the  sup- 
posed biliary  vessels  are  almost  constantly  pre- 
sent, and  less  frequently  the  salivary  and  gastric, 
and  least  frequently  the  anal  vessels,  which  have 
not  been  observed  in  many  species. 

Alimentary  canal  of  the  larva. — The  most 
simple  form  of  alimentary  canal  we  have  yet 
met  with  in  insects  exists  in  apodal  larvse 
of  parasitic  Ilymenoptera,  as  in  Ichneumon 
Alropos,  which  undergoes  all  its  changes 
within  the  cavity  of  the  abdomen,  between  the 
alimentary  canal  and  muscular  structures  of  the 
larva  and  pupa  of  Sphinx  liguslri  or  Acherontia 
Atropos.  It  consists  simply  of  an  elongated 
sac,  very  much  dilated,  and  greatly  resembling 
a  Florence  flask,  and  occupies  nearly  the  whole 
of  the  interior  of  the  body  of  the  parasite.  The 
oesophagus  is  short  and  very  distinct,  and  termi- 
nates in  the  second  segment  in  a  well-deve- 
loped valve  formed  by  a  duplicate  of  the  mu- 
cous and  muscular  coats.  Behind  this  the 
whole  forms  one  dilated  continuous  cavity,  ex- 
tended as  far  as  the  anal  segment,  but  com- 
pletely imperforate  and  slightly  intussuscepted 
at  its  extremity,  where, when  the  partis  carefully 

*  Id.  loc.  cit. 


INSECTA. 


967 


Alimentary  canal  ' of  Carabus  monilis. 

h,  (Esophagus  ;  t,  gizzard,  or  provcntriculus  ;  k, 
vcntriculus  or  digestive  stomach  ;  /,  ilium  ;  m  n, 
colon,  with  cajcal  glands  ;  o,  rectum  ;  p,  hepatic 
vessels  ;  q,  their  point  of  insertion ;  s,  anal  ves- 
sels ;  a,  b,  v,  a  gastric  vessel ;  a,b,n  portion  of  the 
lining  of  the  gizzard. 

examined  by  transmitted  light,  there  is  a  slight 
appearance  of  circular  fibres.  Its  texture 
throughout  is  distinctly  muscular,  both  longitu- 
dinal and  transverse  muscular  fibres  being  dis- 
tinctly visible  in  every  part  of  it,  and  of  nearly 
uniform  size.  This  is  a  remarkably  low  form 
of  development  in  an  insect  which  afterwards 
becomes  one  of  the  most  perfectly  organized  of 


its  class.  Tlve  next  simple  form  of  alimentary 
canal  occurs  in  the  same  order  of  insects,  as  in 
the  larva  of  the  common  Hornet,  Vespa  crabro, 
in  which  it  consists  of  a  straight  and  gradually 
enlarging  tube,  extended  as  far  backwards  as 
the  eleventh  segment,  where  it  becomes  con- 
stricted, and  forms  a  short  small  intestine, 
receiving  at  the  same  time  the  insertions  of 
very  minute  hepatic  vessels,  after  which  the 
intestine  becomes  again  slightly  enlarged  to 
form  a  rudimentary  colon.  The  next  somewhat 
more  developed  form  is  found  in  the  Apida,  as 
in  Anthophoru  rctusa,  in  which  the  canal  forms 
a  distinct  oesophagus,  which  terminates  in  a  very 
slight  dilatation,  and  then  gradually  enlarging, 
passes  onwards,  as  in  the  Hornet,  until  it  ac- 
quires its  largest  diameter  in  the  eleventh  seg- 
ment, and  becomes  constricted  to  form  the 
small  intestine,  receiving  laterally  at  the  same 
time  the  insertions  of  the  hepatic  vessels.  The 
small  intestine  then  passes  forwards,  and  after 
making  one  short  sigmoid  turn  backwards,  ends 
in  a  straight  colon  and  anal  aperture,  which  is 
distinctly  developed  in  this  insect  towards  the 
latter  part  of  the  larva  period,  at  which  time, 
after  the  insect  has  become  full  grown  and 
ceased  to  feed,  we  have  observed  feces  passed 
from  it,  but  we  have  reason  to  believe  that  the 
anal  aperture  is  not  developed  until  that  period, 
since  no  feces  are  found  in  the  cell  in  which 
the  larva  is  inclosed  until  after  the  larva  is  full- 
grown,  and  has  eaten  the  whole  of  the  food  that 
was  stored  up  with  it  when  the  cell  was  closed 
by  the  parent.  In  the  larvae  of  some  Coleop- 
tera,  as  in  the  Lamellicornes,  there  is  almost  as 
simple  a  form  of  the  alimentary  canal  as  in  the 
Apida.  In  these,  as  in  Melolontha  vulgaris, 
(jig.  425,)  it  commences  in  a  short  and  narrow 
oesophagus,  which  opens  by  a  valve  into  a  very 
capacious  stomach  that  extends  backwards  to 
the  twelfth  segment  of  the  body,  where  it  is 
gradually  decreased  in  size,  and  ends  in  a  nar- 
rowed pylorus,  which  is  divided  internally  by 
a  valve  from  a  short  and  narrow  intestine, 
that  passes  forwards  beneath  the  stomach, 
and  ends  in  a  very  large  colon,  which  at  its 
commencement  is  dilated  into  an  immense 
coecum,  and  is  in  general  distended  with  feces. 
It  terminates  beneath  the  middle  of  the 
posterior  half  of  the  stomach  in  a  rectum, 
which  passes  directly  to  an  anal  aperture. 
In  our  dissection  of  this  larva  we  did  not  observe 
theexact  pointat  which  the  biliary  vessels  enter, 
but  nevertheless  they  exist,  although  less  distinct 
than  in  the  perfect  insect.  They  were  observed 
by  Swammerdam  in  the  larva  of  Ori/ctcs  nasi* 
cornis,*  entering,  four  in  number,  at  the  pylo- 
rus. In  this  and  other  lamellicorn  larva:  the 
surface  of  the  digestive  cavity  is  increased  by 
the  addition  of  three  series  of  ccecal  appen- 
dages. The  first  surround  the  cardiac  extre- 
mity, and  consist  of  twelve  coecal  tubes,  with 
their  apices  directed  forwards,  and  dilated  on 
each  side  into  four  smaller  cceca,  so  that  each 
one  has  somewhat  the  appearance  of  a  fern- 
leaf.  From  the  situation  which  they  occupy, 
these  may  perhaps  be  regarded  as  salivary 
organs.    A  little  beyond  the  insertion  of  these 

*  Biblia  Nat.  tab.  xxvii.  fig.  V.  c. 


968 


INSECTA. 


Fig.  425 


Lateral  viexv  of  the  alimentary  canal  of  the  larva  of 
Melohmtlia  vulgaris,  with  the  three  series  of  gastric 


vessels  the  stomach  is  slightly  constricted,  and 
receives  the  insertions  of  another  set  of  caeca, 
which  differ  from  the  last  in  being  single,  co- 
nical, and  directed  backwards.  At  some  dis- 
tance beyond  these,  the  stomach  is  encircled 
by  a  third  set  of  caeca,  which  differ  from  both 
the  preceding  in  being  united  in  pairs  at  their 
base,  and  inserted,  with  their  apices  directed 
forwards,  near  the  posterior  part  of  the  stomach. 
Those  coeca,  both  of  the  second  and  third 
series,  which  are  nearest  to  the  upper  part 
of  the  stomach,  are  the  shortest.  These  cceca 
are  not  analogous  to  the  hepatic  vessels,  or  ra- 
ther those  usually  so  designated,  but  to  the 
gastric  glands  which  cover  the  stomach  in  the 
Carabida  (Jig.  424)  and  Lucanida  (Jig.  428), 
and  appear  in  this  voracious  larva  designed  to 
secrete  a  fluid  that  may  be  necessary  to  enable 
the  stomach  to  digest  the  immense  quantity  of 
vegetable  matter  taken  into  it.  In  the  Lepi- 
dopterous  larvae  the  canal  is  scarcely  more 
developed  than  in  the  Coleopterous,  since, 
although  the  oesophagus  is  elongated,  and 
the  larger  intestines  are  somewhat  more 
complicated,  no  series  of  gastric  glands  are  de- 
veloped. We  believe  we  have  seen  those  which 
surround  the  cardiac  extremity  in  some  liowbi/- 
cida,  as  in  Odonestis  potatoria,  immediately 
after  the  insect  was  killed,  but  merely  as  little 
rounded  protuberances,  the  character  of  which 
was  completely  lost  after  the  insect  had  been 
preserved  for  a  short  time  in  spirits  of  wine. 
They  exist  also  very  distinctly  in  the  Sphinx. 
In  this  order  it  commences  by  a  distinct  oeso- 
phagus (fig.  364,  c),  which  terminates  by  a  val- 
vular orifice  in  the  third  segment  in  a  long  and 
very  muscular  stomach  (C),  around  which  the 
six  longitudinal  bands  are  very  distinct,  as  also 
are  the  transverse  muscular  ones.  At  the  com- 
mencement of  the  eleventh  segment  it  becomes 
constricted,  and  terminates  in  a  distinct  pylo- 
rus, which  ends  in  a  short  ilium  (e),  into  the 
middle  of  which,  on  each  side,  are  received  the 


Fie.  426. 


Xn 


united  termination  of  the  hepatic  vessels  (f ), 
winch,  having  extended  along  the  sides  of  the 
stomach  as  far  forwards  as  the  seventh  segment, 
are  convoluted  around  this  and  the  remaining 
portion  of  the  canal.  Immediately  behind  the 
ilium  the  canal  is  developed  in  a  six  double- 
lobed  caecum  (g),  and  immediately  afterwards 
into  an  immense  sacculated  colon  (/»),  termi- 
nated by  a  very  short  rectum.  The  longitu- 
dinal bands  are  particularly  distinct  on  the 
colon,  and  extend  from  Us  posterior  part  to  the 
external  muscular  tegument  forming  the  retrac- 
tors of  the  colon  and  rectum.  In  the  active 
larvae  of  (Joleoptera  the  alimentary  canal  be- 
comes still  more  developed,  it  commences  in 
the  larvae  of  the  Carabida,  Culosoma  st/cu- 
phanta  (fig.  426),  according  to  Burmeisier,*  in 
a  very  short  oesophagus  (H), 
that  opens  at  the  posterior 
part  of  the  pro-thoracic  seg- 
ment into  a  large  cylindrical 
stomach  (K),  which  is  ex- 
tended throughout  the  great- 
er part  of  the  body,  very  si- 
milar in  appearance  to  that 
of  the  Lepidopteva.  This 
is  called  by  Burmeister  the 
cruw.  It  opens  directly 
into  another  cylindrical  sto- 
mach, much  narrower  and 
nearly  of  the  same  length, 
but  more  muscular  than  the 
preceding,  and  receiving  at 
its  posterior  extremity  (Q), 
where  it  forms  internally  a 
distinct  pyloric  valve,  the 
hepatic  vessels.  Burmeister 
remarks  that  there  is  no 
valve  of  separation  between 
the  first  and  second  of  these 
stomachs,  nor  any  rudiment 
of  the  gizzard,  which  exists 
in  the  perfect  insects  of  this 
order  (fig.  424,  i).  These 
are  succeeded  by  a  small 
intestine  or  ilium  (L), 
which  is  of  some  length, 
and  together  with  the  se- 
cond stomach  forms  several 
convolutions  in  the  body 
between  the  fust  stomach, 
or  craw,  and  the  great  in- 
testine or  colon  (M),  which 
follows  it,  and  terminates 
the  canal  in  a  protruded 
Alimentary  canal  of  anal  aperture  (U).  The 

the  larva  of  Calo-  co]on>  as  ln  most  larva?,  is 
soma    sycophanta.  muscular  and  folded 

( Burmeister. )  ■>  .  .  , 

transversely,  and  altogether 

the  canal  is  more  developed  than  in  the  pre- 
ceding instances,  as  also  are  its  appendages 
the  hepatic  vessels,  which  are  exceedingly 
long,  although  no  cceca  are  developed  upon 
them.  In  the  lihinchophora  and  Longicornes 
there  is  a  still  higher  form  of  alimentary  canal, 
as  observed    by   Burmeisterf  in  Culundra 

*  Transactions  of  Entomol.  Society  of  London, 
vol.  i.  part  3. 

t  Zur  Naturgescliichte  dcr  Gattung  Calandra. 
Beilin,  1837. 


7 


INSECTA. 


969 


Sommeri,  and  as  seen  by  ourselves  in  Callidiwn 
luridum.  In  Calandra,  which  in  external  ap- 
pearance is  scarcely  more  perfect  than  the 
apodal  larva  of  Hymenoptera,  the  alimentary 
canal  (jig.  427)  approaches  much  in  form, 


Fig.  427. 


size,  and  complication  of  its  parts  to  that  of 
the  perfect  insect.  It  commences  behind  the 
pharynx  in  a  very  short  pear-shaped  oesopha- 
gus (II),  which  opens  by  a  valve  into  a  dilated 
bag-shaped  crop  (I),  analogous  probably  to 
the  first  stomach  of  the  larva  of  Ccuospma.  This 
is  continuous  by  a  narrowed  passage  with  the 
proper  digestive  cavity,  around  the  middle  part 
of  which  (K)  are  developed  many  conical  glan- 
dular papillae  or  gastric  vessels,  that  do  not 
appear  to  have  been  noticed  in  the  larva  of 
Culusoma,  which  instead  of  subsisting  upon 
hard  vegetable  substances  like  these  Curculio- 
nidic,  preys  upon  the  soft  bodies  of  living  cater- 
pillars, and  consequently  does  not  require  for 
the  digestion  of  its  soft  animal  food  and  juices 
so  complicated  a  structure  as  those  which  de- 
vour large  quantities  of  crude  vegetable  matter, 
as  is  the  habit  of  the  Lamellicornes,  or  the  hard 
and  less  easily  solvent  woody  fibre  or  coverings 
of  insects  devoured  by  the  Calandra  or  the 
perfect  Carabida;.  At  the  posterior  extremity 
of  the  digestive  stomach  in  this  larva  are  in- 
serted, as  before  seen,  the  biliary  vessels,  not 
singly   around  the  sides  of  the  canal,  but  by 


the  union  of  four  of  these  tubes  in  a  common 
duct.  This  peculiarity  is  remarkable,  as  it 
occurs  in  some  species  in  the  perfect  in- 
sect. Besides  these  vessels  there  are  two 
others  somewhat  smaller,  which  are  inserted 
separately,  a  little  anterior  to  the  common  duct. 
These  have  been  supposed  to  be  analogous 
to  pancreatic  vessels,  but  they  are  similar 
in  almost  every  respect  to  those  which  are 
inserted  by  a  common  duct,  and  hence  may 
be  supposed  to  have  nearly  the  same  functions. 
We  have  noticed  similar  vessels  inserted  sepa- 
rately from  the  supposed  hepatic  vessels  in  the 
Dijticidte  and  in  Timarc/ia,  which  certainly 
leads  to  the  conclusion  that  they  have  some 
difference  of  function.  The  ilium  (L)  is  of 
great  length,  and  more  convoluted  than  we 
have  yet  seen  it  in  any  larva,  and  ends  in  a  very 
muscular  cylindrical  colon  (M  N),  terminated 
by  a  short  rectum.  A  similar  and  perhaps 
even  more  highly  developed  form  of  alimentary 
canal  exists  in  Callidum  luridum,  in  which  the 
anterior  portion  of  the  oesophagus  commences 
with  a  small  neck,  and  is  then  enormously  di- 
lated, after  which  it  becomes  gradually  narrowed 
and  constricted,  and  is  joined  to  a  second  sto- 
mach, which  in  like  manner  is  also  dilated  at 
its  anterior  extremity.  In  the  middle  part  of 
its  course  it  is  twice  folded,  and  is  covered  with 
minute  coeca,  as  in  Calandra,  like  which  it  ter- 
minates in  a  valvular  pylorus,  and  receives  at 
the  same  time  the  insertions  of  the  hepatic  ves- 
sels. The  ilium  is  also  of  considerable  length, 
is  exceedingly  muscular,  and  is  dilated  in  two 
parts  of  its  course  before  k  terminates  in  a 
straight  and  very  muscular  colon  and  short 
rectum,  as  in  Calandra.  The  length  and  com- 
plication of  the  intestines,  therefore,  appear  to 
have  some  reference  to  the  quality  of  the  food 
to  be  digested,  since  it  is  well  known  that  the 
food  of  these  latter  insects  is  of  difficult  assi- 
milation, being  as  it  is  chiefly  the  hard  ligneous 
fibres  of  vegetable  matter;  but  they  cannot  be 
received  as  always  indicatory  of  a  carnivorous 
vegetable  feeder,  since,  as  above  remarked,  the 
length  of  the  canal  is  considerable  in  one  en- 
tirely carnivorous  larva, while  it  is  much  shorter 
in  some  herbivorous,  and  particularly  in  polleni- 
vorous  larva?,  as  in  the  Melulont/ia  and  the 
apodal  Hymenoptera. 

In  the  perfect  insect,  the  length  of  the  ali- 
mentary canal  is  not  more  indicatory  of  the  ha- 
bits of  the  species  than  in  the  larva.  It  is 
nearly  as  long,  and  is  more  complicated,  in  the 
rapacious  Carabida:  (Jig.  423)  than  in  the 
honey-sipping  Lepidoptera,  whose  food  is  en- 
tirely liquid,  while,  as  we  have  seen,  it  is  only 
a  very  short  tube  in  the  pollenivorous  larva, 
which  subsists  upon  a  mixture  of  pollen  and 
honey  ;  but  in  the  perfect  insect,  which  subsists 
upon  honey  alone,  and  which  it  might  be  sup- 
posed requires  little  power  of  digestion,  the 
canal  is  long  and  tortuous.  In  the  rapacious 
Carabida,  it  is  from  two  to  three  times  the 
length  of  the  whole  body.  At  its  commence- 
ment at  the  pharynx  it  is  funnel-shaped,  and 
opens  directly  into  the  oesophagus  (fig.  424,//), 
which  is  gradually  enlarged  as  it  passes  through 
the  thorax,  until  it  arrives  at  the  meta-thoracic 
segment,  where  it  becomes  greatly  dilated,  and 


970 


INSECTA. 


forms  a  large  bag  or  crop,  which  we  shall  pre- 
sently see  more  perfectly  developed  in  the 
Ilaustellata.  While  passing  into  the  abdomen, 
this  part  becomes  suddenly  constricted,  and 
terminates  in  a  short  neck,  immediately  behind 
which  is  an  oval  and  very  muscular  gizzard  (£), 
which  is  developed  internally  into  four  broad 
longitudinal  horny  ridges  (a,  b),  armed  with 
strong  sharp  bristles,  as  formerly  shewn  by 
Leon  Dufour*  in  insects  of  this  family.  Be- 
tween these  ridges  are  two  channels  armed  in 
like  manner  with  a  double  row  of  minute 
hairs,  which  assist  in  more  minutely  comminu- 
ting the  hard  parts  that  are  passed  into  the 
gizzard  and  escape  trituration  by  the  ridges. 
The  substance  of  the  gizzard  is  particularly 
muscular,  and  resembles  in  colour  the  gizzard  of 
a  bird.  On  its  external  surface  the  thin  shining 
pentonceal  coat  is  very  distinctly  seen.  At  its 
base  the  gizzard  is  much  constricted,  and  the 
ridges  within  it  meet  together  so  as  to  form  a 
distinct  valve,  by  which  this  is  divided  from  the 
next  portion  of  the  alimentary  canal,  the  chylific 
ventricule  (k).  This  part  is  capacious  and 
muscular,  and  the  double  mucous  lining  within 
it  is  very  distinct.  It  is  of  considerable  length, 
and  is  gradually  decreased  in  size  from  its  com- 
mencement to  its  termination  at  the  pyloric 
valve,  where,  as  in  the  larva,  it  receives  the  he- 
patic vessels.  It  is  covered  throughout  its 
whole  course  by  an  immense  number  of  appa- 
rently ccecal  vessels  («,  b,  c),  which  in  the  upper 
half  of  its  course  are  of  considerable  length, 
but  in  the  lower  become  gradually  more  and 
more  shortened.  Burmeisterf  thinks  these 
ccecal  vessels  are  derived  entirely  from  the  inner 
or  mucous  coat  of  the  ventricule  by  intussus- 
cepted  portions,  which  pass  through  the  mus- 
cular coat  between  the  fibres  which  are  pushed 
aside  by  them,  and  consequently  that  they  do 
not  derive  any  covering  from  the  muscular  coat, 
but  of  this  we  have  considerable  doubt.  In- 
ternally they  certainly  open  each  by  a  distinct 
valvular  oritice,  derived  from  the  mucous  lining, 
as  we  have  seen  in  Carabus  monilis  (b),  and 
externally  are  covered  by  the  peritonceal  coat, 
and  on  each  side  are  furnished  with  a  minute 
ramifying  tracheal  vessel,  derived  from  the  tra- 
cheae which  are  distributed  over  the  alimentary 
canal,  as  shewn  by  Dufour.  We  cannot,  how- 
ever, imagine  that  they  derive  no  covering  from 
the  muscular  coat  of  the  ventricule,  more  espe- 
cially while  it  is  admitted  that  the  ccecal  appen- 
dages attached  to  the  anterior  and  posterior  por- 
tion of  the  ventricule  in  the  Gryllida  derive  a 
portion  of  their  structure  from  the  muscular 
coat  as  well  as  the  mucous.  These  are  most 
decidedly  secretory  organs,  and  elaborate  a 
fluid,  probably  distinct  in  its  chemical  composi- 
tion from  that  of  the  biliary  vessels  at  the 
pyloric  extremity  of  the  stomach.  The  ilium 
(/)  is  of  considerable  length.  On  its  exterior 
surface  the  longitudinal  muscular  bands  are 
distinctly  marked.  It  is  much  longer  in  pro- 
portion to  the  other  parts  of  the  intestine  in  the 
perfect  insect  than  in  the  larva.  It  terminates 
in  a  very  large  pear-shaped  colon  (;«,  n),  the 

*  Annales  des  Sciences  Naturelles,  torn.  ii.  pi.  20. 
t  Op.  cit.  p.  132. 


upper  part  of  which  corresponds  to  the  ceecum, 
which  we  shall  see  highly  developed  in  some 
other  species.  It  is  there  marked  by  six  elon- 
gated elevated  glandular  protuberances,  situated 
between  the  longitudinal  muscular  bands. 
These  elevations  seen  on  the  exterior  of  the  part 
correspond  to  others  which  we  have  found 
equally  strongly  marked  in  the  colon  of  Hy- 
menoptera,  and  we  suspect  are  the  mucous 
glands  of  the  great  intestine.  The  colon  is 
usually  distended  with  faeces,  and  terminates  in 
a  very  short  narrow  rectum  (o).  At  each  side 
of  the  colon  are  situated  the  anal  or  urinary 
vessels  (s),  which  we  shall  presently  describe. 
This  may  serve  to  illustrate  the  general  form  of 
the  alimentary  canal  in  carnivorous  Coleoptera. 
In  certain  parts  of  its  course  it  is,  however, 
more  developed  in  other  species.  Thus  in  the 
Dytkida,  we  have  found  the  oesophagus  in 
Hydulicus  cinereus,  as  described  by  authors  in 
Dyticux,  expanded  into  a  large  crop-shaped 
bag,  and  the  stomach  shorter  than  that  of  the 
Carabidce,  and  covered  by  long  cceca  throughout 
its  whole  extent.  It  receives  at  its  base  the  in- 
sertion of  four  large  hepatic  vessels,  and  also 
two  very  much  smaller  ones,  similar  to  those 
just  seen  in  the  larva  of  the  Culandrli.  The  anal 
vessels  are  also  present,  but  their  excretory 
bladder  is  larger,  and  its  neck  much  shorter 
than  in  the  Carabidm.  The  most  remarkable 
structure  is  in  the  proventriculus  or  gizzard. 
The  external  appearances  of  this  part  resembles 
that  of  an  acorn  in  its  cup.  It  is  exceedingly 
muscular,  and  is  armed  internally  with  four  re- 
markable teeth  arranged  around  its  inferior  por- 
tion, between  four  horny  ridges  developed  from 
the  mucous  lining  of  the  part,  and  covered  with 
very  strong  stiff  hairs,  as  in  the  Carabidtc.  Each 
of  these  teeth  is  broad  and  somewhat  oval  at  its 
base,  and  in  shape  resembles  a  helmet,  the  crest 
of  which  is  acute,  and  armed  with  two  sharp- 
pointed  prominences  adapted  for  cutting  the 
food,  which  it  is  known  is  swallowed  more  rapa- 
ciously and  less  comminuted  by  these  insects 
than  by  Carabida.  This  form  of  alimentary 
canal  with  a  gizzard  and  gastric  cceca  exists  in 
the  Silphidte,*  and  most  of  the  carnivorous 
feeders.  Thus  it  exists  also  in  Staphylinidte,\ 
in  which  we  have  found  the  gizzard  in  Creophi- 
lus  maxillosus  armed  with  double  longitudinal 
horny  ridges,  covered  with  stiff  hairs  as  in  Ca- 
rabus, like  which  also  the  stomach  is  covered 
with  gastric  cceca,  which  are  larger  at  the  an- 
terior than  at  the  posterior  part  of  the  organ. 
The  anal  vessels  are  also  largely  developed. 
Dufour  has  observed  the  same  in  Stap/iyli- 
nus  erythropterus.  The  gizzard  is  also  found 
in  some  of  the  Neuroptera.  It  is  very  largely 
developed  in  the  carnivorous  Pumtrpa  com- 
munis, in  which,  however,  we  have  not  found  it 
thrown  into  regular  longitudinal  folds,  but  into 
transverse  and  oblique  rugae  covered  with  stiff 
hairs.  The  alimentary  canal  in  this  species  is  of 
considerable  length,  perhaps  nearly  three  times 
that  of  the  body.  The  oesophagus  is  short? 
but  is  developed  at  its  under  surface  into 
a  minute  oval  crop,  perfectly  distinct  from 

*  Dufour,  op.  cit.  torn.  iii.  pi.  13,  fig.  5. 
t  Id. 


INSECTA. 


971 


the  common  cavity  of  the  oesophagus,  although 
not  separated  from  it  by  a  valve,  neither  is  the 
oesophagus  separated  by  a  valvular  structure 
from  the  gizzard.  The  chylific  stomach  is  ex- 
ceedingly long  and  cylindrical,  but  is  without 
gastric  coeca,  like  the  larva  of  Car-abidee,  since 
like  that,  the  Punorpa  appears  to  subsist  rather 
by  sucking  the  juices  than  by  swallowing  the 
hard  parts  of  the  body  of  its  victims.  Thus, 
then,  although  in  the  Cicindelida '(fig.  37,  vol.  1), 
the  canal  is  scarcely  longer  than  the  body,  as 
formerly  shewn  by  Dufour,  and  since  fre- 
quently instanced  as  proving  that  the  length  or 
shortness  of  the  canal  is  characteristic  of  a  car- 
nivorous or  phytophagous  feeder,  we  cannot 
admit  that  the  length  of  the  digestive  organs, 
and  the  existence  of  a  gizzard  and  gastric  ves- 
sels, are  indicatory  of  predacity  of  habits  in  the 
insect,  because  a  similar  conformation  of  parts 
exists  often  in  strictly  vegetable  feeders.  The 
existence  and  length  of  these  parts  seem  rather 
to  refer  to  the  comparative  digestibility  of  the 
food  than  to  its  animal  or  vegetable  nature. 

Among  the  more  omnivorous  feeders,  as  in 
the  Forficulida,  the  gizzard  is  still  present. 
In    Forjicula  auriculuria  the  oesophagus  is 
long  and  dilated,  and  a  short,  broad,  and  very 
muscular  gizzard  is  present.    Internally  it  is 
thrown  into  six  longitudinal  folds,  which  pro- 
ject for  some  distance  at  their  extremity  into 
the  cavity  of  the  digestive  stomach,  to  the  en- 
trance of  which,  when  closed,  they  serve  as  a 
valve.  The  canal  of  this  insect,  which,  although 
in  part  carnivorous  in  its  habits,  certainly  is 
not  of  the  most  rapacious  nature,  but  lives 
equally  upon  the  juices  of  fruits  and  flowers,  is 
scarcely  longer  than  that  of  the  most  predaceous 
Cieindela  or  Dyticus,  since  it  passes  almost  in 
a  direct  line  through  the  body,  making  but  one 
slight  convolution,  a  further  proof  that  the 
length  of  the  canal  must  not  be  taken  as  a  cri- 
terion whereby  to  judge  of  the  habits  of  a 
species.    This  will  apply  equally  to  the  om- 
nivorous Gryllidee,  in  which  there  exists  a  short 
alimentary  canal,  but  a  gizzard  of  more  com- 
plicated structure  than  that  of  Di/ticida.  In 
these  insects  the  two  layers  of  the  mucous 
coat  are  visible  even  in  the  oesophagus.  The 
second  layer  is  distinctly  glandular  and  secre- 
tory, and  in  it  there  are  many  thousands  of 
very  minute  granulary  glandular  bodies,  which 
probably  secrete  the  fluid  that  is  often  ejected 
from  the  mouth  of  the  insect  when  captured. 
The  inner  layer,  or  proper  mucous  lining,  is 
often   folded  longitudinally,  and  in  Acrida 
viridissima  these  folds,  which  are  six  in  number, 
assist  to  form  a  valve  between  the  oesophagus 
and  gizzard.    They  are  each  armed  with  five 
very  minute  hooked  teeth,  and  continued  into 
the  gizzard  develope  many  more  in  their  course 
through  that  organ.    These  first  teeth  are  ar- 
ranged around  the  entrance  to  the  gizzard,  and 
seem  designed  to  retain  the  insufficiently  com- 
minuted food  and  pass  it  on  to  that  organ. 
Next  to  these  in  succession  on  each  of  the  lon- 
gitudinal ridges  are  four  flat,  broad,  and  some- 
what quadrate  teeth,  each  of  which  is  very 
finely  denticulated  along  its  free  margin.  These 
extend  about   half-way  through  the  gizzard. 
They  appear  to  be  alternately  elevated  and  de- 


pressed during  the  action  of  the  gizzard,  and  to 
serve  to  carry  on  the  food  to  the  twelve  cutting 
teeth  with  which  each  ridge  is  also  armed,  and 
which  occupy  the  posterior  part  of  the  organ. 
These  teeth  are  triangular,  sharp-pointed,  and 
directed  posteriorly,  and  gradually  decrease  in 
size  in  succession  from  before  backwards.  Each 
tooth  is  very  strong,  sharp-pointed,  and  of  the 
colour  and  consistence  of  tortoise-shell,  and  is 
armed  on  each  side  by  a  smaller  pointed  tooth. 
These  form  the  six  longitudinal  ridges  of  the 
gizzard,  between  each  two  of  which  there  are 
two  other  rows  of  very  minute  teeth  of  a  tri- 
angular form,  somewhat  resembling  the  larger 
ones  in  structure  occupying  the  channels  be- 
tween the  ridges.    The  muscular  portion  of  the 
gizzard  is  equally  interesting.    It  is  not  merely 
formed  of  transverse  and  longitudinal  fibres, 
but  sends  from  its  inner  surface  into  the  cavity 
of  each  of  the  large  teeth  other  minute  but 
powerful  muscles,  a  pair  of  which  are  inserted 
into  each  tooth.    The  number  of  teeth  in  the 
gizzard  amounts  to  two  hundred  and  seventy, 
which  is  the  same  number  in  these  Gryllidee 
as  found  formerly  by  Dr.  Kidd*  in  the  mole- 
cricket.    Of  the  different  kinds  of  teeth  there 
areas  follows:  seventy-two  large  treble  teeth, 
twenty-four  flat  quadrate  teeth ;  thirty  small 
single-hooked  teeth,  and  twelve  rows  of  small 
triangular  teeth,  each  row  being  formed  of 
twelve  teeth.    This  is  the  complicated  gizzard 
of  the  higher  Orthoptera.    In  the  same  insect 
immediately  posterior  to  the  gizzard  the  chylific 
stomach  is  expanded  on  each  side  into  two 
large  rounded  coeca,  into  the  upper  part  of  which 
some  minute  vessels  are  traced  which  in  appear- 
ance resemble  the  hepatic  vessels.  Posteriorly 
to  these  ccsca  the  stomach  becomes  narrowed 
and  makes  one  convolution,  and  receives  around 
its  termination  the  hepatic  vessels,  which  are 
small  but  very  numerous.  It  then  is  continued 
backwards  as  a  long  ilium,  and  terminates  in  a 
muscular  banded    colon  without  a  distinct 
rectum.    The  whole  length  of  this  alimentary 
canal  does  not  exceed  more  than  about  one 
length  and  a  half  of  that  of  the  body.    A  simi- 
lar structure  exists  in  the  Blattida.    In  these 
insects  eight  large  vessels  are  inserted  around 
the  commencement  of  the  stomach  behind  the 
gizzard.   Four  of  these  are  long  and  four  short, 
and  as  observed  by  Burmeister,  these  have  been 
thought   to   be   analogous  to   pancreatic  or 
gastral  salivary  organs.  In  the  proper  Locustidte 
there  is  only  a  rudimentary  gizzard,  as  Bur- 
meister has  shown  in  Locusta  migratoriu,  in 
which  the  interior  lining  of  the  whole  oeso- 
phagus and  crop  is  covered  by  an  immense 
number  of  very  minute  horny  teeth,  for  the 
purpose   of  comminuting  the  hard  ligneous 
matter  which  we  have  sometimes  found  in 
foreign  specimens.     The  rudiments  of  the 
gizzard  exist  in  six  flat  pieces,  studded  with 
minute  teeth  like  the  lining  of  the  oesophagus. 
The  commencement  of  the  stomach  is  sur- 
rounded by  two  sets  of  coecal  appendages,  six 
in  each  set,  and  similar  in  form  to  those  of  the 
second  set  in  the  larva  of  Melolontha,  like 
which  those  on  the  under  surface  are  the 

J  Phil.  Trans.  1826. 


972 


INSECTA. 


Alimentary  canal  of  Lucanus  cervus. 

G,  anterior  muscles  of  the  pharynx;  H,  oeso- 
phagus -,  I,  gizzard  ;  K,  chylific  stomacli ;  L,  ilium  ; 
M,  colon  (ccecal  portion  of)  ;  N,  colon  ;  O,  rectum  ; 
a,  frontal  ganglion  on  the  vagus  ;  b,  vagus  ;  c,  an- 
terior lateral  ganglion  connected  to  the  vagus. 

longest.  These  are  evidently  analogous  to  the 
vessels  in  Blatta. 

But  one  of  the  most  remarkable  forms  of 
alimentary  canal  with  reference  to  the  habits  of 
the  insect  exists  in  the  male  Lucanus  cervus 
(Jig.  428),  which  subsists  entirely  upon  fluid 
aliment,  as  proved  by  the  observations  of  natu- 
ralists, and  confirmed  by  the  fact  that  its  mouth 
is  unfitted  for  mastication.  In  this  insect  the 
oesophagus  (H)  is  usually  long  and  narrow,  and 
terminates  in  the  meso-thorax  in  a  well  deve- 
loped gizzard  (I),  as  in  the  Carabus,  and  this 
is  succeeded  by  a  long  chylific  stomach  (K), 
covered  throughout  its  whole  extent  by  very 
minute  rudimentary  coeca,  as  first  noticed  by 
Dufour.  It  makes  three  distinct  convolutions, 
and  is  then  divided  by  a  pylorus,  which  re- 
ceives four  hepatic  vessels  (P)  from  an  ex- 


ceedingly short  ilium  (L),  which  passes  directly 
in  an  enormous  colon.  The  upper  portion  of 
this(M)  is  divided  from  the  lower  (N),  which 
is  thus  divided  into  colon  and  ccecum.  It  ter- 
minates in  a  long  folded  rectum  (N,  O),  and 
the  whole  are  usually  filled  with  faeces.  Now 
this  insect,  in  which  both  gizzard  and  gastric 
vessels  are  present,  can  scarcely  require  these 
parts  for  the  purpose  of  triturating  its  food, 
which  is  entirely  fluid,  besides  which,  being 
one  of  those  species  that  undergo  a  complete 
metamorphosis,  it  can  scarcely  be  supposed  to 
be  simply  a  remains  of  what  existed  in  the 
larva  state.  The  presence  of  the  gizzard  may 
be  looked  upon  as  somewhat  anomalous. 
Again  it  may  be  remarked,  that  in  Hymenoptera 
the  stomach,  which  in  many  species  digests 
only  liquid  concentrated  food  in  the  form  of 
honey,  is  much  longer  than  in  those  instances, 
as  in  Orthoptera,  in  which  the  food  is  less 
easily  digestible.  In  the  Apid<e  there  is  a  large 
alimentary  canal  with  an  immense  number  of 
biliary  vessels  attached  to  it,  while  in  the 
Tentliredinifke,  which,  besides  honey,  subsist 
partly  upon  the  pollen  of  flowers,  as  we  have 
observed  in  Athalia  centifolia,  there  is  a  very 
short  alimentary  canal  and  even  a  distinct 
gizzard  (Jig.  429,  I),  situated   between  the 


Fig.  429. 


Section  of  the  crop  (H),  gizzard  (I),  awl  stomach 
(K)  of  Athalia  centifolia;.   (Newport,  Prize  JEssuy). 

stomach  (K)  and  the  dilated  oesophagus  (II) 
or  crop  of  this  order.  We  have  detected  pollen 
in  the  proventriculus  of  this  insect,  so  that  in 
these  we  have  still  further  proof  that  the  length 
of  the  canal  is  not  always  indicatory  of  the 
habits  of  the  species. 

In  the  Lepidoptera,  which,  we  have  seen,  in 
the  larva  state  have  a  short  intestine,  have  a  com- 
paratively long  one  in  the  perfect.  In  the 
Sphinx  ligustri  (fig.  430),  the  oesophagus  (/>)  is 
long  and  narrow,  and  in  the  metathoracic  seg- 
ment is  dilated  into  a  large  crop  (t)  connected 
by  a  distinct  neck,  but  not  divided  from  it  by  a 
valve.  This  is  usually  filled  with  air,  and  has 
thence  been  called  the  sucking  stomach,  but  in 
the  Diptera,  in  which  it  also  exists,  and  com- 
mencing much  nearer  the  pharynx  is  extended 
backwards  as  a  long  and  gradually  enlarging 
tube  until  it  reaches  the  anterior  part  of  the 
abdomen,  where  it  is  expanded  transversely 
into  a  large  bag,  we  have  certainly  found  it 
partially  filled  with  food.  This  has  often  been 
found  to  be  the  case  in  the  common  flesh-fly. 
In  EristalisJloreus(1)  we  have  found  it  partially 
filled  with  yellow  pollen  from  the  flowers  of 
the  ragwort,  upon  which  the  insect  was  cap- 
tured.   We  have  at  the  same  time  observed 


INSECTA. 


973 


Fig.  430. 


Fig:  431. 


Alimentary  canal  of  Sphinx  ligustri. 

the  pollen  in  the  canal  leading  to  the  bag,  in 
the  oesophagus,  and  in  the  stomach  itself.  A 
gizzard  does  not  exist  either  in  the  Diptera  or 
Lepidoptera,  but  there  is  a  slight  rudiment  of 
it  in  the  Sphinx  (i).  The  stomach  of  Lepidop- 
tera is  in  general  short,  oval,  or  a  little  elon- 
gated (k),  and  always  very  muscular,  and  as 
in  other  insects,  the  hepatic  vessels  (p)  enter 
at  its  pyloric  extremity  (q).  The  ilium  (/)  is  of 
considerable  length.  In  the  Sphinx  it  makes 
seven  folds,  and  then  passes  straight  to  the 


A  Umentary  canal  of  Pontia  brassicee. 

colon,  which  is  developed  anteriorly  into  a  very 
large  coecum  (///),  and  terminates  in  a  narrow 
short  rectum  («).  Throughout  its  whole  course 
it  is  covered  by  the  hepatic  vessels.  In  the 
Pontia  brassica  (fig.  431),  the  digestive  sto- 
mach is  preceded  by  a  very  muscular  and 
transversely  banded  portion  of  canal  resembling 
the  stomach  of  Hymenoptera.  It  is  in  the  pre- 
cise situation  of  the  gizzard  in  other  orders,  and 
appears  to  be  the  representative  of  that  part  in 
tli is  insect.  The  true  stomach  is  long  and  oval, 
and  the  ilium  is  longer  than  in  the  Sphinx,  and 
the  ccecum,  colon,  and  rectum  are  all  distinct. 
In  the  Diptera  the  alimentary  canal  is  usually 
very  long,  and  is  scarcely  at  all  shorter  in  the 
carnivorous  than  in  the  omnivorous  feeders. 

Appendages  of  the  canal. — The  first  of  these, 
the  salivary  glands,  are  very  frequent  in  most 
of  the  orders,  but  vary  greatly  in  form  and 
number.  In  Lepidoptera  they  are  simple 
elongated  tubes  (A),  which  extend  into  the 
thorax  and  are  convoluted  beneath  the  oeso- 
phagus and  anterior  portion  of  the  alimentary 
canal.  In  the  larva  they  constitute  the  silk 
vessels,  and  empty  themselves  by  a  single  duct 
through  the  spinneret  on  the  floor  of  the 
mouth.  They  are  formed  of  three  por- 
tions ;  first,  the  excretory,  which  is  thin  and 
transparent,  and  is  gradually  enlarged  as  it 
passes  backwards  along  the  body ;  second,  the 
apparently  secretory  portion  of  the  organ,  which 
is  of  an  elongated  cylindrical  form,  externally 
transversely  marked  as  if  formed  of  muscular 
fibres,  and  internally  covered  with  a  vast 
number  of  rounded  glandular  bodies,  as  we 


974 


INSECTA. 


have  seen  in  the  recently  detached  vessel  of 
Vanessa  urtica  ;  and  lastly  of  a  third  portion, 
which  consists  of  a  minute  vessel,  extended 
from  the  apparently  coecal  extremity  of  the 
middle  portion  of  the  organ,  as  formerly  shewn 
also  by  Lyonet  in  the  Cossus.  In  the  perfect 
insect  these  parts  still  exist,  but  very  much 
reduced  in  size.  In  the  Cossus  Lyonet  has 
shewn  four  of  these  vessels,  two  of  which,  the 
proper  silk  vessels,  open  by  a  single  excretory 
duct,  and  the  others  separately  into  the  cavity 
of  the  mouth.  In  some  Coleoptera,  as  in  the 
Blapsidce,  these  organs  are  formed  of  many 
ramifying  tubes  united  on  each  side  of  the 
oesophagus  into  a  single  duct.  In  others,  as  in 
the  Orthoptera  and  Hymenoptera,  they  con- 
sist of  an  immense  number  of  rounded,  opaque, 
glandular  bodies,  aggregated  together  in  small 
clusters,  which  communicate  by  many  small 
ducts,  inserted  at  irregular  distances,  with  a 
large  and  partially  convoluted  common  or  ex- 
cretory duct,  that  opens  on  each  side  of  the 
mouth,  so  that  each  of  these  collections  of 
glands  resembles  a  bunch  of  grapes  or  currants. 
Each  of  these  rounded  granules,  or  acini  if  we 
may  so  call  them,  receive  a  minute  vessel, 
but  whether  this  is  distributed  over  its  surface 
or  is  received  directly  into  its  substance  we 
have  been  unable  to  ascertain.  These  aggre- 
gations of  salivary  glands  are  usually  situated 
on  each  side  beneath  the  oesophagus  in  the  pro- 
thorax,  and  are  very  distinct  in  the  Orthoptera 
and  Hymenoptera,  in  which  they  have  been 
often  noticed.  Muller  has  seen  them  in 
Phasma,  Treviranus  in  Apis,  Burmeister  in 
Locustida,  Grt/llidte,  and  Termes,  and  we  have 
also  seen  them  in  Loc ustidce  and  Gryllida  among 
the  Orthoptera,  and  in  Bombus,  Apis,  Ant/io- 
phora,  and  Athalia  among  the  Hymenoptera. 
Their  existence  in  the  latter  genus  is  somewhat 
interesting  from  the  circumstance  that  the  large 
quantity  of  salivary  fluid  which  these  organs 
seem  calculated  to  produce  appears  to  be 
entirely  employed  in  moistening  the  dry  pollen 
of  flowers  upon  which  the  perfect  insect  chiefly 
subsists,  before  it  is  passed  into  the  oesophagus, 
and  not  in  the  habits  or  in  constructing  of  a 
nest,  as  is  the  case  with  the  bee,  which  always 
employs  it  as  a  solvent  for  the  wax  in  the  con- 
struction of  its  combs.  In  the  latter  insect, 
according  to  Burmeister,  the  evacuating  duct 
of  these  organs  is  a  minute  spiral  vessel  re- 
sembling a  trachea,  and  empties  itself  into  the 
tube  of  the  proboscis  or  ligula.  The  form  and 
number  of  these  salivary  organs  varies  in  the 
different  classes;  the  usual  number  is  two, 
but  in  Apis  Cimex  and  Palex  there  are  four, 
each  pair  of  which  unite  into  one  duct,  while 
in  JVepa  there  are  as  many  as  six.*  In  the 
Tabanida  there  are  only  two  short  ccecal  tubes, 
into  which  many  minute  vessels  empty  them- 
selves.! Those  gastric  vessels,  which  are  in- 
serted at  the  commencement  of  the  digestive 
stomach  we  have  above  stated  have  been  re- 
garded as  salivary  organs,  but  there  is  consi- 
derable doubt  respecting  their  real  function. 
Burmeister  considers  them  to  be  analogous  to 
the  pancreas,  but  if  this  be  admitted  to  be  the 


case  in  the  Orthoptera,  those  vessels  also  which 
cover  the  exterior  of  the  digestive  stomach  in 
the  carnivorous  Coleoptera  must  be  of  the 
same  description,  since  both  empty  themselves 
into  the  digestive  stomach.  But  we  cannot 
coincide  with  him  in  this  opinion,  since  from 
an  experiment  which  we  shall  presently  notice 
there  is  reason  to  believe  that  the  fluid  poured 
into  that  cavity  during  digestion  is  of  an  acid 
nature,  analogous  to  that  which  is  found  under 
similar  circumstances  in  the  stomach  of  ver- 
tebrata ;  while  that  of  the  proper  salivary 
organs  is  believed  to  be  alkaline,  as  was  for- 
merly supposed  by  Rengger.  Treviranus  also 
believed  the  same  of  the  saliva  of  the  honey- 
bee, having  witnessed  its  employment  by  this 
insect  in  the  formation  of  its  combs.  We  have 
also  seen  this  insect  reduce  the  perfectly  trans- 
parent thin  white  scale  of  newly  secreted  wax 
to  a  pasty  or  soapy  consistence,  by  kneading  it 
between  its  mandibles,  and  mixing  it  with  a 
fluid  from  its  mouth,  before  applying  it  to 
assist  in  the  formation  of  part  of  a  new  cell, 
so  that  we  have  good  reason  to  believe  that  ihe 
salivary  fluid  thus  employed  asa  solvent  for  the 
otherwise  brittle  wax  is  of  an  alkaline  quality. 

The  Malpighian  or  supposed  biliary  vessels 
(Jig-  432,  p )  usually  enter  the  canal,  as  we 
have  seen,  at  the  pylorus.  They  vary  greatly 
in  number  from  two  to  twenty  or  even  a  hun- 
dred, as  in  some  of  the  Orthoptera  and  Hymen- 
optera, but  in  all  insects  their  function  appears 
to  be  similar.  They  are  usually  from  four  to 
six  in  number,  and  are  very  long  tubes  that 
pass  from  their  insertion  or  opening  into  the 
canal  behind  the  pylorus  directly  forwards 
about  half  way  along  the  sides  of  the  stomach, 
and  are  then  reflected  backwards  as  far  as  the 
ilium,  around  which  and  the  colon  they  make 
many  convolutions,  and  in  the  Lepidoptera 
terminate,  or  perhaps  we  ought  rather  to  say 
originate,  each  in  a  minute  vessel,  which  be- 
comes smaller  and  smaller  in  proportion  to  its 
length,  and  in  which  we  can  perceive  no  dis- 
position to  form  a  coecal  termination,  although 
we  have  been  unable  to  trace  it  to  its  origin, 
which  is  certainly  in  the  vicinity  of  the  posterior 
part  of  the  colon.  Of  this  we  have  satisfied 
ourselves  by  following  these  vessels  in  the  larva 
of  Odonestis  potatoria,  which  the  colour  of 
their  contents,  an  opaque  bright  yellow,  has 
rendered  practicable.  We  have  traced  them 
until  the  yellow  colour  has  disappeared  in  an 
opaque  white,  and  this  has  been  also  lost  in  a 
perfectly  transparent  fluid,  after  which  we  have 
been  unable  to  follow  the  vessels  further.  In 
other  insects  they  appear  to  end  in  coecal  ex- 
tremities, but  we  certainly  could  not  observe 
this  in  the  larvae  of  Lepidoptera.  It  has  also 
been  supposed  by  some  anatomists  that  these 
vessels  form  a  double  communication  with  the 
alimentary  canal,  but  this  has  entirely  escaped 
our  observation.  In  the  larva  of  Sphinx  ligustri 
and  most  other  Lepidoptera  these  vessels  are 
covered  by  an  immense  number  of  minute  oval 
coeciform  dilatations  (fig.  432,  a ),  as  is  also 
the  case  in  some  of  the  perfect  Coleoptera, 
Mclolontha*   as  shown   by  Dufour,  Straus 


Burmeister,  op.  cit.  p.  146.  t  Id.  145. 


*  See  Animal  Kingdom,  vol.  i.  fig.  38,  c. 


INSECTA. 


975 


Fig.  432. 


a,  part  of  the  hepatic  vessel  of  the  larva  of  Sphinx 
ligustri  when  nearly  full  grown,  showing  the 
cceca  ;  h,  part  of  the  same  in  the  pupa,  the  coeca 
disappearing, 

Durckheim,  and  others.    From  each  of  these 
supposed  coeca  in  the  larva  of  sphinx  we  have 
traced  an  exceedingly  minute  and  transparent 
vessel  which  has  appeared  to  be  connected  with 
other  delicate  ramifications,   and  sometimes 
with  the  immense  quantity  of  adipose  sacculi 
with  which  the  whole  viscera  are  surrounded. 
These  Malpighian  vessels  undergo  considerable, 
changes  while  the  insect  is  passing  from  the 
larva  to  the  perfect  state.    The  cceca  begin  to 
disappear  soon  after  the  insect  has  entered  the 
pupa  state  (b),  and  not  a  trace  of  them  is  dis- 
coverable in  the  perfect  insect,  so  that  the 
function  of  the  organ  is  gradually  diminished 
in  activity.    During  the  larva  state  they  exhibit 
a  remarkable  peculiarity  at  their  connexion  with 
the  alimentary  canal  which  seems  to  have  some 
reference  to  their  function.    It  is  a  dilatation 
at  the  point  of  union  of  these  vessels  in  the 
sphinx  to  form  a  single  duct  that  opens  into 
the  ilium,  and  if  these  be  hepatic  vessels  may 
represent  a  gall-bladder,  as  once  observed  to 
us  by  Dr.  Grant,  but  the  exact  function  of  the 
vessels  is  very  difficult  to  determine.  The 
following  observation  which  we  made  in  the 
summer  of  1832  and  havesince  repeated  seems 
a  little  to  show  the  nature  of  the  contents  of 
these  vessels,  and  also  of  other  parts  of  the 
alimentary  canal.     We  gave  sugared  water, 
coloured  with  indigo,  to  some  specimens  of 
Vanessa  urlica  which  had  been  confined  for 
several  hours  without  food  after  they  had  left 
the  pupa  state.     On  examining  the  insects 
about  two  hours  afterwards  the  stomach  was 
found  filled  with  fluid  containing  a  great  quan- 
tity of  pink-coloured  granules,  which  appeared 
to  be  the  vegetable  indigo  acted  upon  by  the 
acid  contents  of  the  stomach  by  which  it  had 
become  saturated,  thus  distinctly  indicating  the 
presence  of  an  acid  in  the  stomach  during 
digestion.    But  it  was  remarkable  that  some  of 
the  indigo  that  had  passed  the  pyloric  extremity 
of  the  stomach,  where  these  supposed  biliary 
vessels  enter,  and  had  also  passed  throughout 
the  whole  length  of  the  ilium  and  even  in  part 
into  the  colon,  had  been  restored  again  to 
its  original  dark  blue  colour,  thus  indicating 
the  presence  of  an  alkalescent  fluid  secreted 
either  by  the  hepatic  vessels  or  the  ilium  along 
which  the  indigo  had  passed.     But  another 
curious  circumstance  was  that  the  hepatic  ves- 
sels also  partook  of  the  same  pinkish  hue  as 
the  contents  of  the  stomach,  which  seemed  to 
indicate  that  the  contents  of  these  also  are  acid. 


The  conclusions  we  drew  from  these  observa- 
tions, which  we  repeated  very  carefully  in 
1834,  were,  that  there  is  an  acid  gastric  juice 
secreted  in  the  stomach  during  digestion,  that 
the  contents  of  the  so-called  hepatic  vessels  are 
probably  also  acid,  and  that  an  alkaline  fluid 
is  secreted  by  the  ilium,  otherwise  the  indigo 
reddened  in  the  stomach  could  not  have  been 
restored  to  its  original  colour.  These  circum- 
stances seem  to  lead  to  the  conclusion  that  the 
Malpighian  vessels  are  rather  uriniferous  than 
biliary,  more  especially  as  they  have  been 
found  by  Chevreul*  and  Audouinf  to  contain 
uric  acid;  but  if  this  be  really  their  function, 
a  question  then  arises  why  they  are  inserted  so 
near  to  the  pyloric  extremity  of  the  stomach  in 
almost  all  insects,  and  the  excreted  fluid  be 
thus  required  to  traverse  nearly  one-half  of  the 
whole  alimentary  canal  before  it  is  ejected  from 
the  body  ?  This  consideration  still  inclines  us 
to  suspend  our  opinion  as  to  their  true  function, 
and  leads  us  still  to  believe  that  they  may  be 
in  some  way  connected  with  the  function  of 
digestion  and  assimilation. 

The  anal  or  proper  uriniferous  organs. — We 
agree  with  Burmeister  that  the  anal  are  the 
true  urinary  organs.  They  do  not  in  general 
evacuate  their  contents  directly  into  the  canal, 
but  on  each  side  of  the  anus.  They  exist,  as 
we  have  seen,  in  the  Curabidte  (Jig.  424,  s ), 
and  their  general  form,  as  long  ago  shown  by 
Dufour  in  these  insects,  is  that  of  a  long  vessel 
convoluted  upon  the  colon  and  emptying  itself 
into  an  oval  or  kidney-shaped  vesicle  on  each 
side  of  the  colon,  and  terminating  in  a  single 
duct  close  to  the  anus.  Dufour  found  the 
minute  vessel  on  the  colon  connected  with  an 
aggregation  of  rounded  glandular  bodies,  each 
connected  with  the  vessels  by  a  very  minute 
filament,  but  we  have  overlooked  this  structure 
in  our  own  examinations.  Neither  have  we 
seen  it  in  the  Di/ticida,  in  which  each  urini- 
ferous organ  commences  in  two  apparently 
coecal  tubes,  which,  after  being  a  little  convo- 
luted, unite  into  one  which  empties  itself  into 
a  vesicle  on  each  side  of  the  colon  and  rectum. 
Similar  vesicles  have  been  shown  by  Dufour  in 
the  Staphylinida,  as  in  Staphylinus  erythropterus 
and  in  the  Sdphida,  in  both  which  we  have 
ourselves  distinctly  seen  them  arising  by  a 
single  vessel  which  empties  itself  into  an  urinary 
bladder  on  each  side  of  the  anus.  In  the 
Silphida  this  bladder  opens  directly  into  the 
termination  of  the  rectum. 

The  adipose  tissue. — This  tissue,  which  it  is 
necessary  to  allude  to  in  connexion  with  the 
organs  of  nutrition,  consists  of  an  immense 
number  of  little  transparent  membranous  vesicles 
filled  with  opaque  adipose  matter,  which,  in 
the  generality  of  insects,  is  perfectly  white,  but 
in  others,  as  in  the  butterflies,  is  of  a  bright 
yellow  colour.  The  vesicles  are  usually  very 
irregular  in  form,  being  sometimes  nearly  oval 
and  at  others  elongated  or  triangular.  They 
communicate  freely  with  each  other  and  form 
a  most  intricate  web  or  reticulated  structure. 
They  cover  the  whole  of  the  abdominal  viscera 

*  Straus  Durckheim, Considcrat.  tkc.  1828,  iv.  251, 
t  L'institut.  135. 


976 


INSECTA. 


like  the  omentum  of  the  higher  animals,  and 
they  are  extended  also  among  the  muscles; 
between  which  they  occupy  the  interstices,  both 
between  the  different  layers  and  the  tegumen- 
tary  skeleton.  They  do  not  form  in  the  abdo- 
men one  continuous  surface  like  the  mesentery, 
but  are  simply  attached  to  each  other,  and  to 
the  surrounding  structures  by  constricted  por- 
tions, which  allow  of  the  freest  communication. 
They  are  most  abundant  in  the  abdomen,  but 
are  extended  into  the  thorax  and  cover  more 
particularly  the  nervous  cord.  There  are  but 
very  few  in  the  region  of  the  head  or  in  the 
extremities.  We  have  never  yet  seen  them 
in  actual  communication  with  bloodvessels, 
although  we  have  observed  them  attached  by 
minute  points  along  the  whole  course  of  the 
dorsal  vessel,  in  the  abdomen,  as  if  they  were 
in  some  way  connected  with  the  return  of  the 
blood  to  the  auricular  space  that  appears  to 
surround  that  organ.  It  is  amongst  these 
vesicles  in  particular  that  the  Malpighian  or 
so-called  biliary  vessels  extend  around  the 
alimentary  canal,  and  the  tracheae  ramify  among 
them  in  the  greatest  abundance,  but  we  have 
not  observed  them  distributed  over  the  sides  of 
individual  vesicles  as  over  some  other  structures. 
These  circumstances  lead  us  to  suspect  that 
the  vesicular  structures  are  in  some  way  con- 
nected with  the  circulatory  system,  although 
they  cannot  be  regarded  either  as  arteries  or 
veins.  May  they  not  serve  the  purpose  of 
lymphatics,  while  they  become  at  the  same  time 
depositaries  of  the  nutrient  matter?  Oken  and 
Treviranus  appear  to  have  considered  them  as 
analogous  to  the  liver,  and  the  latter  author 
has  supported  his  opinion  by  the  existence  of  a 
somewhat  analogous  structure  in  the  scorpion, 
which  is  believed  to  be  the  liver  of  that  animal. 
That  they  are  most  intimately  connected  with 
the  function  of  nutrition  is  proved  by  the  cir- 
cumstance that  they  exist  in  the  greatest 
abundance  at  the  period  when  the  larva  ceases 
to  feed,  just  before  it  enters  the  pupa  state; 
that  their  contents  are  gradually  diminished 
during  that  condition  ;  and  that  they  disappear 
most  rapidly  towards  the  latter  end  of  the 
pupa  state,  when  the  organs  of  generation  are 
in  the  most  rapid  progress  of  development. 
After  the  insect  has  entered  the  perfect  state 
their  contents  have  nearly  disappeared.  Added 
to  these  circumstances  we  have  observed  that, 
during  the  earliest  periods  of  the  larva  state, 
the  quantity  of  adipose  substance  contained  in 
the  vesicles  is  very  small,  and  also  that  in  all 
perfect  insects  that  pass  the  winter  in  a  state  of 
hybernation  the  quantity  of  adipose  matter  is 
much  greater  than  in  those  which  do  not  live 
through  the  summer,  while  it  has  nearly  all 
disappeared  in  these  insects  after  they  have  left 
their  hybernacula  in  the  spring.  We  have 
remarked  these  circumstances  particularly  in 
the  later  broods  of  butterflies,  which  being 
hatched  at  the  end  of  autumn  pass  the  winter 
as  hybernants  and  appear  again  in  the  spring, 
and  we  have  constantly  noticed  the  same  thing 
in  the  large  females  of  Bombus  terrestris,  which 
live  through  the  winter.  From  these  circum- 
stances there  can  be  no  doubt  but  that  the 
adipose  matter  is  intimately  connected  with  the 


function  of  nutrition  and  the  circulatory  system, 
while  the  free  communication  which  we  have 
constantly  observed  to  exist  between  the  vesicles 
seems  to  favour  our  opinion  that  they  may 
serve  the  office  of  lymphatic  vessels.  That 
they  cannot  be  supposed  to  answer  the  purpose 
of  a  liver  seems  evident  from  the  increase  and 
diminution  of  their  contents  at  certain  periods, 
while  their  apparent  connexion  with  the  Mal- 
pighian vessels  seems  to  support  the  opinion  we 
have  advanced,  more  especially  if  these  be  regard- 
ed as  uriniferous  rather  than  as  biliary  organs. 

Circulatory  system. — It  was  formerly  sup- 
posed that  there  was  a  total  absence  of  a  circu- 
latory motion  of  the  fluids  in  insects,  and  that 
the  whole  body  was  nourished  by  a  simple 
imbibition  of  fluids  that  occupied  the  cavities 
of  its  different  regions.  This  opinion  was 
strengthened  by  the  circumstance  of  the  air- 
vessels  being  distributed  to  every  separate 
structure  and  ramifying  extensively  even  upon 
the  most  delicate  organs,  a  fact  so  remarkable 
that  it  appeared  entirely  to  obviate  the  necessity 
for  a  motion  of  the  fluids,  and  led  to  the  pro- 
mulgation of  Cuvier's  beautifully  ingenious 
theory,  that  as  the  blood  could  not  be  carried  to 
be  aerated  in  a  separate  organ  or  lung,  the  air 
was  in  consequence  brought  into  contact  with 
it  throughout  the  whole  body.  But  the  dis- 
covery of  Carus  in  1827  of  an  actual  motion 
of  the  fluids,  and  subsequently  the  discovery 
by  Straus  Durckheim  of  a  structure  in  the 
dorsal  vessel,  which  clearly  indicates  the  true 
use  of  this  organ  as  a  centre  of  circulation, 
have  sufficiently  shown  that  insects  do  not 
differ  from  other  animals  in  the  absence  of  a 
circulation  of  their  fluids,  whatever  modifica- 
tions may  exist  in  the  form  and  situation  of 
the  organs  by  which  it  is  accomplished. 

The  heart  or  great  dorsal  vessel  (fig.  433,  A) 
is  an  elongated  tapering  organ,  which,  in  every 
insect,  occupies  the  middle  line  of  the  dorsal 
surface  of  the  body,  and  extends  from  the 
posterior  part  of  the  penultimate  segment  of 
the  abdomen,  through  the  thorax,  into  the  first 
segment  or  head  of  the  animal.  That  portion 
of  it  which  is  situated  in  the  abdominal  region 
is  the  proper  analogue  of  the  heart  of  other 
other  animals,  and  is  composed  of  a  certain 
number  of  separate  compartments  or  chambers 
(a).  It  is  distinctly  muscular,  and  is  of  con- 
siderable diameter,  and  is  that  part  which  is 
actively  employed  in  circulating  the  blood. 
The  other  part  which  extends  through  the  thorax 
is  much  narrower  than  the  preceding,  and  is 
not  divided  into  chambers,  but  is  one  conti- 
nuous vessel  that  becomes  gradually  narrower 
as  it  passes  through  the  thorax  to  the  head, 
where  it  is  divided  into  separate  branches  (B). 
This  part  is  less  actively  employed  than  the 
abdominal,  being  only  the  great  vessel  through 
which  the  blood  is  sent  from  the  muscular 
heart  to  the  system,  and,  consequently,  repre- 
sents the  aorta.  In  the  structure  of  the  abdo- 
minal portion  or  true  heart  we  recognize  three 
separate  coats,  two  of  which  are  most  distinctly 
marked,  and  form  the  substance  of  the  organ ; 
but  the  third  or  external  one  is  very  delicate 
and  not  easily  observed.  Straus  Durckheim 
recognises  but  two  distinct  structures,  the 


INSECTA. 


977 


Fig.  433. 


A,  dorsal  vessel  or  heart  of  Lucamis  cermis. 

a,  the  valves  or  chambers  ;  b,  b,  the  lateral  mus- 
cles ;  c,  the  supposed  auricular  space  around  the 
vessel. 

B,  the  division  into  vessels  of  tlw  anterior  or  aortal 
portion,  of  the  dorsal  vessel  in  the  larva  of  Vanessa  urticce. 

C,  interior  of  the  dorsal  vessel  ( Straus ). 

a,  interior  of  the  valve,  showing  the  transverse 
fibres;  b,  the  auriculo -ventricular  opening  and 
valve  into  the  chambers  of  the  vessel ;  c,  semi- 
lunar valve  ;  d,  inter-ventricular  valve. 

internal  one  (C,  a)  formed  of  a  transversely 
folded  and  striated  membrane  which  is  thickest 
towards  the  middle  of  each  chamber,  and  an 
external  one  formed  of  strong,  smooth,  mus- 
cular, longitudinal  fibres.  Burmeister*  has 
suggested  that  these  may  be  only  two  layers  of 
one  muscular  structure,  and  that  the  presence 
of  a  structureless  lining  or  inner  membrane 
must  then  be  presumed,  although  it  be  too 
delicate  to  be  actually  detected  by  observation. 
The  third  or  external  coat  is  a  transparent  struc- 
tureless membrane  which  covers  the  outer 

'    *  Op.  cit.  p.  156. 

VOL.  II. 


surface  of  the  heart,  and  is  extended  directly 
over  it  without  following  the  reflexions  inwards 
of  the  muscular  coat,  where  it  forms  the  valves 
or  separations  between  the  different  chambers. 
The  division  of  the  organ  into  separate  cham- 
bers is  effected  by  means  of  an  intussusception 
or  reflexion  inwards  and  forwards  of  the  whole 
muscular  structures.    A  portion  of  each  side 
of  the  heart  is  first  extended  inwards  so  as 
very  nearly  to  meet  a  corresponding  portion 
from  the  opposite  side,  and  then  reflected  back- 
wards forms,  according  to  Straus,*  the  inter- 
ventricular valve  (d),  which  separates  each 
chamber  from  that  which  follows  it.  Posteriorly 
to  this  valve,  at  the  anterior  part  of  each  cham- 
ber, is  a  transverse  opening  or  slit  (i),  the 
auficulo-ventricular  orifice,  through  which  the 
blood  passes  into  each  chamber,  and  imme- 
diately behind  it  is  a  second  but  much  smaller 
semilunar  valve  (c),  which,  like  the  first,  is 
directed  forwards  into  the  chamber.     It  is 
between  these  two  valves  on  each  side  that  the 
blood  passes  into  the  heart  and  is  prevented 
from  returning  by  the  closing  of  the  semilunar 
valve.    When  the  blood  is  passing  into  the 
chamber  the  inter-ventricular  valve  is  thrown 
back  against  the  side  of  the  cavity,  but  is 
closed,  when,  by  the  contraction  of  the  trans- 
verse fibres,  the  diameter  of  each  chamber  is 
narrowed  and  the  blood  is  forced  along  into  the 
next.cbamber.    The  number  of  these  openings 
and  chambers  in  different  species  of  insects 
does  not  yet  appear  to  have  been  satisfactorily 
ascertained.    Straus  has  figured  nine  chambers 
in  Melolontha,  and  consequently  eight  pairs  of 
openings,  but  we  have  not  been  able  to  observe 
more  than  seven  pairs  of  openings  in  Lucanus 
cervus,  in  which  the  anterior  pair  is  almost 
hidden  at  the  commencement  of  the  aorta. 
Burmeisterf  states  that  he  could  not  find  more 
than  four  pairs  of  openings  in  the  larva  of 
Culosomu,  while  he  remarks  that  according  to 
Midler's  description  of  the  heart  in  Pliasma 
there  appears  to  be  but  one  pair  in  that  species. 
In  Bombits  terrestris  we  have  as  yet  detected 
but  five  pairs,  but  we  nevertheless  suspect  that 
these  discrepancies,  or  apparent  differences  in 
the  number  of  these  openings,  arise  less  from 
so  great  a  diversity  in  the  actual  number  than 
from  some  of  them  being  overlooked  during 
dissection,  since  we  have  invariably  found  eight 
pairs  in  Sphinx  ligustri,  both  in  the  larva  and 
perfect -state,  as  well  as  in  other  Lepidoptera ; 
while  in  the  Bombus  examined  by  us  the 
dissection  was  not  so  carefully  made  as  to 
enable  us  to  state  positively  that  there  are  not 
more  than  we  have  mentioned.    The  external 
form  of  the  chambers  in  the  very  thick  and 
muscular  heart  of  Lucanus  is  shown  in  the 
drawing  we  have  given  of  this  structure.  When 
the  heart  is  examined  by  transmitted  light,  there 
is  seen  around  it  a  bright  space  (A,  c)  in  which 
we  have  observed  the  blood  flov\irig  very  freely 
in  living  specimens  of  Agrion,  and  which  we 
regard  with  Straus  as  an   auricular  cavity, 
apparently  bounded  by  a  loose  membrane,  and 

*  C'onsiderat.  &c.  p,  356. 
f  Op.  cit.  p.  154. 

3  s 


978 


INSECTA. 


into  which  the  blood  is  received  both  in  return- 
ing backwards  from  the  head  and  thorax 
and  laterally  from  the  sides  of  the  abdomen. 
We  have  observed  a  similar  space  in  many 
insects,  particularly  in  Asilus  crabroniformis 
(Jig.  434,  D),  and  also  in  Bombus  terrestris. 


Fig.  434. 


One  valve  of  the  heart  of  Asilus  crabroniformis. 

a,  the  chamber;  b,  the  lateral  muscles;  c,  the 
auricular  space  ;  the  arrows  denote  the  course  of 
the  blood. 

In  this  insect  we  have  observed  the  fibres  of 
the  heart  crossing  each  other  in  an  oblique  di- 
rection, forming  as  it  were  a  series  of  festoons 
around  the  posterior  part  of  each  chamber. 
These,  like  the  transverse  fibres  observed  in 
Melolontha  by  Straus,  contract  the  diameter 
of  each  chamber,  and  extend  the  vessel.  Be- 
sides the  proper  muscular  structure  of  the  heart 
itself,  there  are  attached  on  each  side  of  the 
organ  several  sets  of  muscular  fibres,  arranged 
in  pairs  along  the  upper  and  under  surface  of 
each  chamber.  Each  set  of  these  fibres,  con- 
verging to  a  tendon,  and  passing  outwards, 
forms  a  triangular  muscle  (A,  b,  b),  which 
is  attached  to  the  lateral  surface  of  each  seg- 
ment. These,  which  have  been  called  the 
wings  of  the  heart,  assist  by  their  contraction 
to  shorten  and  expand  the  chambers  at  the 
auricular,  or  receiving  period  of  the  heart's  mo- 
tions, while,  as  just  explained,  the  transverse 
and  diagonal  muscles  occasion  the  ventricular, 
by  their  contracting  and  narrowing  the  diameter 
of  each  chamber.  It  is  between  the  upper  and 
under  set  of  the  lateral  muscles  that  we  believe 
the  auricular  space  to  exist,  bounded  by  a  de- 
licate membrane.  The  thoracic  or  aortal  por- 
tion of  the  heart  commences  at  the  anterior 
part  of  the  first  abdominal  segment,  where  the 
organ  bends  downwards  to  pass  under  the 
metaphragma,  and  enter  the  thorax.  When  it 
has  entered  that  region  it  immediately  ascends 
again  between  the  great  longitudinal  dorsal 
muscles  of  the  wings,  and  passes  onwards 
until  it  arrives  at  the  posterior  margin  of  the 
pronotum ;  it  then  again  descends  and  con- 
tinues its  course  along  the  upper  surface  of  the 
oesophagus,  with  which  it  passes  beneath  the 
cerebrum,  anterior  to  which,  and  immediately 
above  the  pharynx,  it  is  bifurcated  and  divided 
into  several  branches,  as  formerly  noticed  by  us 
in  the  sphinx.*  Previously  to  our  notice,  how- 

*  Phil.  Trans.  1832,  p.  ii.  p.  385. 


ever,  Carus  had  seen  the  course  of  the  blood 
in  the  head  of  insects  following  directions  cor- 
responding to  the  situations  in  which  we  have 
been  able  to  trace  a  distinct  division  of  the  aorta 
into  vessels.  We  have  found  a  similar  division 
of  the  aorta  into  branches  in  several  species  of 
Coleopterous  insects,  as  in  Meloe,  Maps,  and 
Timarcha,  although  we  have  omitted  to  trace 
it  in  Lucanus.  In  the  Sphinx  and  Vanessa 
urticce,  immediately  after  the  aorta  has  passed 
beneath  the  cerebrum  it  gives  off  laterally  two 
large  trunks,  which  are  each  equal  in  capacity  to 
about  one-third  of  the  main  vessel.  These  pass 
one  on  each  side  of  the  head,  and  are  divided 
into  three  branches,  which  are  directed  back- 
wards, but  have  not  been  traced  farther  in  conse- 
quence of  their  extreme  delicacy.  Anterior  to 
these  trunks  are  two  smaller  ones,  which  appear 
to  be  given  to  the  parts  of  the  mouth  and  an- 
tennae, and  nearer  the  median  line  are  two  others, 
which  are  the  continuations  of  the  aorta.  These 
pass  upwards  and  are  lost  in  the  integuments. 
The  whole  of  these  parts  are  so  exceedingly 
delicate  that  we  have  not  as  yet  been  able  to 
follow  them  beyond  their  origin  at  the  termina- 
tion of  the  aorta,  but  believe  them  to  be  con- 
tinuous with  very  delicate  circulatory  passages 
along  the  course  of  the  tracheal  vessels.  It  is 
in  the  head  alone  that  the  aorta  is  divided  into 
branches,  since  throughout  its  whole  course 
from  the  abdomen  it  is  one  continuous  vessel, 
neither  giving  off  branches  nor  possessing  la- 
teral muscles,  auricular  orifices,  or  separate 
chambers.  In  the  larva  state  it  is  far  more 
difficult  to  recognise  the  true  structure  of  the 
vessel  by  actual  dissection  than  in  the  perfect, 
because  the  valves  are  only  in  a  rudimentary 
condition.  But  it  is  easy  to  observe  it  in  the 
bodies  of  living  transparent  specimens,  as  done 
by  Carus,  Wagner,  Bowerbank,  and  others  in 
the  Ephemerida:  and  Agr'wnidm,  in  which  not 
only  the  form  of  the  valves  and  motions  of  the 
vessel  are  distinct,  but  also  the  abundance  of 
globules  that  circulate  in  every  direction.  Even 
in  some  of  the  opaque-bodied  maggots  of  Dip- 
tera  we  have  seen  the  form  of  the  valves  very 
distinctly  through  the  tegument  in  the  eight 
posterior  segments.  When  viewed  in  that  state 
each  chamber  appears  to  be  much  narrower  at 
its  anterior  and  posterior  extremity  than  in  its 
middle  (jig.  358,  D),  and  the  valves  formed 
by  the  reflexion  of  its  parietes  inwards,  although 
distinct,  are  very  small.  Near  the  middle  of 
each  chamber  there  is  attached  on  each  side  a 
narrow  muscle,  which  passing  backwards  is 
attached  to  the  anterior  margin  of  each  seg- 
ment. Between  the  muscle  and  the  heart  in 
each  segment,  a  large  tracheal  vessel  crosses  to 
anastomose  with  its  fellow  on  the  opposite  side, 
and  on  each  side  of  the  dorsal  vessel,  nearly 
in  the  course  of  the  lateral  muscles,  there  is  a 
faint  indication  of  a  line  which  seems  to  form 
the  boundary  of  what  we  regard  as  the  auricular 
space  in  which  the  blood  is  collected  before 
passing  into  the  chambers,  of  which  there  are 
eight  very  distinct  ones  in  these  larvae. 

The  motion  and  course  of  the  blood,  as  will 
be  seen  from  the  above  account  of  the  structure 
of  the  chief  organ  of  the  circulation,  is  first 


INSECTA, 


979 


directly  forwards  in  the  middle  line  of  the 
body,  and  then  backwards  by  the  sides  of  the 
thorax  and  abdomen,  to  the  lateral  and  pos- 
terior parts  of  the  heart,  into  which  it  is  re- 
ceived, by  means  of  transverse  currents  in  each 
segment,  through  the  auricular  space  and  ori- 
fices. This  course,  as  discovered  by  Carus,  is 
indicated  in  the  description  and  diagram  given 
in  a  former  part  of  this  work.*  The  blood, 
which  is  usually  of  a  very  transparent  greenish 
or  yellowish  colour,  is  filled  with  a  great  num- 
ber of  little  particles,  which  were  described  by 
Carus  as  oblong  or  oval,  but  more  correctly 
by  Mr.  Bowerbank  f  as  flattened  oat-shaped 
masses,  which  retain  their  form  while  circu- 
lating through  the  body,  but  like  the  particles 
of  blood  in  Vertebrata  become  globular  imme- 
diately they  are  brought  into  contact  with  water. 
It  is  stated  by  Burmeister  J  that  they  vary  in 
diameter  from  J.jth  to  ^th  of  a  line,  but  they 
differ  also  in  size  in  the  same  individual,  and 
are.  often  rough  or  tuberculated  as  noticed  by 
Edwards,§  and  as  distinctly  seen  in  the  blood  of 
Sphinx  ligustri.  The  motions  of  the  blood,  ren- 
dered perceptible  by  the  presence  of  these  par- 
ticles, was  first  observed  by  Carus  in  the  aqua- 
tic larva  of  Ephemera,  in  which,  as  in  other 
aquatic  transparent  bodied  larvae,  the  particles 
are  very  distinct.  Baker||  and  some  of  the  older 
observers  in  this  country  had  long  before  seen 
motions  of  the  fluids  in  the  limbs  of  some  in- 
sects, but  Carus  first  discovered  the  existence 
of  a  complete  circulation.  Cams  saw  the  blood 
distributed  in  several  streams  from  the  aortal 
«xtremity  of  the  dorsal  vessel  in  the  head  re- 
turning in  currents,  that  entered  the  base  of  the 
antenna.'  and  limbs,  in  which  it  formed  loops, 
and  then  flowing  into  the  abdomen  entered  the 
heart  at  its  posterior  extremity.  Wagner^]  con- 
firmed Carus'  discovery,  and  added  some  new 
observations.  He  saw  the  blood  flowing  back- 
wards in  two  venous  currents,  one  at  the  sides 
of  the  body  and  intestine,  and  the  other  along- 
side of  the  dorsal  vessel,  and  he  discovered 
that  the  blood  not  only  entered  at  the  ex- 
tremity of  the  dorsal  vessel,  but  also  at  the 
sides  in  each  segment,  at  the  valves  discovered 
by  Straus.  Both  Carus  and  Wagner,  however, 
believed  that  the  currents  of  blood  observed 
by  them  were  not  inclosed  in  distinct  parietes 
or  vessels.  Mr.  Bowerbank,**  in  repeating  these 
observations,  saw  also  the  blood  distributed  by 
the  dorsal  vessel  forming  loops  in  the  antennas 
and  limbs,  and  then  passing  backwards  m  la- 
teral and  transverse  currents,  enter  at  the  valves 
into  the  dorsal  vessel.  And  he  also  observed 
and  clearly  denned  the  structure  and  action  of 
the  valves.  He  discovered,  however,  that  the 
currents  of  blood  along  the  sides  of  the  body 
are  really  inclosed  in  distinct  parietes,  and 
do  not  flow  in  the  common  abdominal  cavity, 

*  See  Article  CIRCULATION,  vol.  i.  p.  652.,  fig. 
325. 

t  Entomol.  Mag.  vol.  i.  p.  244. 

$  Op.  cit.  404. 

$  Art.  Blood,  vol.  i.  p.  408. 

||  On  the  Microscope,  vol.  i.  p.  130. 

t  Isis,  1832. 

**  Entomological  Mag.  vol.  i.  April,  1833,  p.  239. 


as  previously  supposed,  the  boundaries  of  the 
vessels  inclosing  these  currents  being  clearly 
definable.  He  has  also  expressed  his  belief 
that  a  "  much  greater  portion  of  the  circulation 
than  we  can  clearly  define  is  carried  on  within 
given  vessels,  as  the  blood  may  frequently  be 
seen  flowing  in  curved  and  other  lines,  and  con- 
fined within  very  narrow  limits,  but  so  deeply 
seated  amidst  the  muscles  and  intestines  as  to- 
tally to  prevent  the  boundaries  of  the  current  from 
being  clearly  observed."  We  are  ourselves  most 
distinctly  of  the  same  opinion,  having  formerly, 
through  the  kindness  of  Mr.  Bowerbank,  been 
allowed  to  examine  the  circulation  in  Ephemera 
by  means  of  his  powerful  microscope.  We 
believe  also  that  we  have  seen  distinct  vessels 
passing  transversely  across  the  dorsal  surface  of 
each  segment,  in  the  direction  of  the  anterior 
part  of  each  chamber  of  the  dorsal  vessel, 
in  the  large  pupa  of  Acherontia  Alropos  and 
Sphinx  ligustri,*  but  whether  these  are  vessels 
returning  to  or  distributed  from  each  chamber, 
as  we  are  most  inclined  to  believe,  is  not  cer- 
tain. If  they  be  not  vessels  distributed  from 
the  heart,  it  is  a  somewhat  curious  circumstance 
that  the  whole  of  the  blood  should  be  first  sent 
to  the  head  of  the  insect,  and  the  viscera  of 
the  abdominal  region  be  nourished  only  by  the 
returning  blood,  which  has  in  part  passed  the 
round  of  the  circulation.  The  only  instance 
in  which  vessels  had  previously  been  supposed 
to  be  distributed  directly  from  the  heart  in  the 
abdomen  was  pointed  out  so  long  ago  as  1824 
by  Professor  Muller,f  who  discovered  a  con- 
nexion of  the  oviducts  with  the  inferior  surface 
of  the  organ  in  many  insects ;  but  these  were 
afterwards  believed  by  Carus,  Treviranus, 
Wagner,  and  Burmeister  to  be  only  ligamen- 
tous connexions.  We  have  observed  these  con- 
nexions in  many  insects,  and  certainly  believed, 
when  we  first  noticed  them,  without  being 
aware  that  they  had  previously  been  seen  by 
Midler,  that  they  were  vascular  structures.  We 
have  traced  them,  especially  in  the  Cardbidd. 
into  direct  connexion  with  the  organ,  but  have 
been  unable  to  observe  at  what  point  the  cavity 
of  the  ovarial  tubes  commences,  or  where  the 
supposed  ligamentous  portion  begins.  We 
have  seen  these  connexions  not  only  in  the 
perfect  insects  but  also  in  the  larvae,  more  espe- 
cially in  the  males  of  Sphinx  ligustri  and 
Odunestis  potatoria.  In  these  larvae  the  two 
oblong  testicles,  not  united  into  one  mass  as  in 
the  perfect  state,  are  each  attached,  side  by 
side,  by  two  short  filaments  to  that  chamber  of 
the  dorsal  vessel  which  is  situated  in  the  ninth 
segment.  One  of  these  attachments  proceeds 
from  the  anterior  and  the  other  from  the  pos- 
terior part  of  each  testicle.  Now,  if  these  at- 
tachments be  not  distinct  vessels,  it  is  remark- 
able that  these  glandular  and  secretory  organs 
should  always  be  connected  by  mere  ligaments 
with  the  great  circulatory  organ,  since,  if  the 
object  of  their  connexion  were  merely  to  retain 
them  in  their  place  in  the  abdomen,  it  would 

*  Dr.  Roget's    Bridgewater  Treatise,   vol.  ii. 
p.  245. 

t  Nova  Acta  Nat,  t.  xii.  2. 


980 


INSECTA. 


probably  be  as  well  answered  by  an  attachment  to 
any  other  part.  These  considerations  certainly 
lead  us  to  hesitate  to  admit  that  they  are  mere 
ligaments.  Whatever  be  their  nature,  as  Muller 
has  observed,  their  existence  is  indubitable. 

Besides  the  parts  now  described,  there  is 
also  another  which  is  connected  with  and 
forms  part  of  the  vascular  system,  but  the  ex- 
istence even  of  which  has  hitherto  been  almost 
overlooked.  This  is  a  distinct  vascular  canal, 
which  is  extended  along  the  upper  surface  of 
the  abdominal  portion  of  the  cerebro-spinal 
cord  in  perfect  Lepidopterous  insects,  and 
which  we  have  traced  from  the  thorax  to  the 
termination  of  the  cord.  We  have  designated 
this  structure  the  supra-spinal  vessel.  It  is 
placed  immediately  above  the  cord,  and  is 
covered  by  transverse  muscular  fibres,  which 
exclude  it  from  the  common  abdominal  cavity, 
and  give  to  the  whole  cord,  when  removed  from 
the  body  and  examined  by  transmitted  light, 
a  flocculent  appearance.  This  appearance  was 
first  noticed  by  Lyonet,*  but  the  vessel  between 
it  and  the  cord  was  not  detected  by  him.  It 
was  subsequently  figured  and  described  by  us 
in  the  Sphinxrf  and  the  whole  of  our  recent 
observations^  have  confirmed  the  opinion  we 
then  entertained  of  it.  It  is  a  most  distinct 
structure  in  the  abdomen  of  the  Sphinx,  and 
niay  be  readily  seen  after  the  abdominal  cord 
has  been  carefully  removed  from  the  body  with 
its  surrounding  structures  and  placed  for  some 
time  in  spirits  of  wine.  We  believe  this  vessel 
to  be  the  chief  means  of  returning  the  blood 
from  the  middle  and  inferior  portion  of  the 
body  to  the  posterior  extremity  of  the  dorsal 
vessel  or  heart,  and  that  it  is  analogous  to  a 
structure  which  we  have  found  to  be  a  supra- 
spinal vessel  §  in  the  Scorpion  and  Centipede, 
that  had  previously  been  supposed  to  be  a 
loose  and  easily  detached  portion  of  the  nervous 
system,  but  which  is  now  proved  to  belong  not 
to  the  nervous  but  to  the  vascular  structures. 
We  are  strongly  inclined  to  suspect  that  this 
supra-spinal  vessel  in  insects  is  connected  with 
the  anterior  portion  of  the  dorsal  vessel  or 
aorta,  in  a  manner  similar  to  the  connexion 
which  was  shown  by  Mr.  Lordfl  to  exist  be- 
tween the  corresponding  structure  and  the  heart 
in  Myriapoda.  (See  Myriapoda.)  We  believe 
also  that  we  have  seen  a  corresponding  vessel  in 
the  larva  of  the  Sphinx,  but  of  so  delicate  a  struc- 
ture as  almost  always  to  elude  detection.  It  will 
thus  be  seen  that  the  blood  certainly  flows  in 
distinct  vessels,  at  least  in  some  parts  of  the 
body  in  perfect  insects,  and  that  vessels  exist 
even  in  the  larva.  But  although  a  circulation 
of  the  blood  has  been  seen  by  Carus,  Wagner, 
and  others  in  many  perfect  insects,  it  has  been 
shown  only  in  the  appendages  of  the  body,  and 
in  those  chiefly  in  recently  developed  specimens, 
while  it  has  been  supposed  to  move  only  in  in- 

*  Recherches  sur  l'Anat.  et  lesMetam.de  diffe- 
rentes  Especes  d'Insectes.  Paris,  1832,  p.  505, 
pi.  lii.  fig.  18.  and  pi.  liv.  fig.  2. 

t  Phil.Trans.p.  ii.  1834,p.395,  pi.  xiv.  fig.9(a). 

}  Medical  Gazette,  March  17,  1838,  p.  973. 

§  Id.  March  17,  1838,  p.  971. 

U  Id.  March  3,  1838,  p.  893. 


tercellular  spaces  and  not  in  distinct  vessels. 
This  opinion,  however,  is  now  invalidated  by 
our  discovery  of  a  supra-spinal  or  great  ventral 
vessel.  A  motion  of  the  fluids  has  been  seen 
by  Carus  in  the  wings  of  recently  developed 
Libellulida,  Ephemera  lulea,  and  E.  margi- 
vatu,  and  Chrysopa  perla;  among  the  Coleop- 
tera  in  the  elytra  and  wings  of  Lanipuris  italica 
and  L.  splendidula,  Melolonlha  solstitiulis,  and 
Dyticus.  But  Carus  was  unable  to  detect  it 
in  the  wings  of  Orthoptera,  although,  accord- 
ing to  Humboldt,*  Ehrenberg  has  seen  it  in  a 
species  of  Mantis,  and  Wagner  in  the  young 
of  Nepa  cinerea  and  Cimex  tectularius  among 
the  Hemiptera ;  but  it  has  not  yet  been  ob- 
served in  the  Hymenoptera.  Burmeister  has 
seen  it  in  Eristulis  tenax  and  E.  nemorum 
among  the  Diptera,  and  Mr.  Tyrrel  f  in  Musea 
domestka  as  well  also  as  in  Geop/iilus  and  Li- 
thobius  forficatus  in  the  Class  Myriapoda.  In 
addition  to  these  Mr.  Bowerbank  has  seen  it  in 
one  of  the  Noctuida,  Phlogophora  metictt- 
losu%  in  the  Order  Lepidoptera,  in  which  it 
was  seen  also  in  the  rudimental  wings  of  some 
pupae  by  Carus.  Some  of  the  most  interesting 
observations  that  have  yet  been  made  upon 
the  motions  of  the  blood  in  these  organs  are 
those  of  Mr.  Bowerbank  §  in  Chrysopa  perla. 
Mr.  Bowerbank  found  that  in  the  lower  wing 
of  this  insect  the  blood  passes  from  the  base 
of  the  wing  along  the  costal,  post-costal,  and 
externo-medial  nervures,  outwards  to  the  apex 
of  the  organ,  giving  oft'  smaller  currents  in  its 
course,  and  that  it  returns  along  the  anal  or 
inferior  nervure  to  the  thorax.  He  states  that 
the  blood  occupies  the  chief  part  of  the  cavi- 
ties of  these  nervures,  in  each  of  the  largest  of 
which  is  a  very  small  trachea.  From  this 
statement  it  has  been  rather  hastily  concluded 
that  the  nervures  of  the  wings  are  only  venous 
trunks,  or  passages  for  the  circulatory  fluids, 
and  are  not  formed,  as  hitherto  supposed, 
chiefly  by  ramifications  of  the  tracheae.  He 
found  tracheae  existing  in  the  larger  of  these 
cavities,  which  measured  only  j^th  of  an  inch 
in  diameter,  while  the  cavities  themselves  mea- 
sured 3<|s  of  an  inch ;  but  in  others  the  tracheae 
measured  ,3TOth,  while  the  cavity  measured  only 
305th.  He  states  also  that  the  tracheae  very  rarely 
give  off  branches  while  passing  along  the  main 
nervures,  and  that  they  lie  along  the  canals  in 
a  tortuous  direction.  In  consequence  of  these 
most  interesting  observations  we  have  examined 
the  wings  of  some  dried  specimens  of  this  in- 
sect, and  have  found  that  there  exists,  as  Mr. 
Bowerbank  remarks,  a  very  large  and  perfectly 
transparent  space  around  the  tracheae,  which  is 
more  or  less  distinct  in  different  specimens,  but 
in  a  few  instances  is  not  observable.  But  we  have 
invariably  found  that  the  tracheae  not  only  exist 
throughout  the  whole  of  the  ramifications  of  the 
wings,  but  also  give  off  branches  at  every  ner- 
vure or  space  along  which  the  fluid  passes. 

*  Burmeistcr's  Manual,  p.  408. 
t  Proceedings  of  the  Royal  Society,  Jan.  15, 
1835. 

%  Entomological  Magazine,  vol.  i.  April,  1833, 
p.  243. 

$  Op.  cit.  vol.  iv.  Oct.  1836,  p.  179,  pi.  xv. 


Now  the  opinion  to  which  we  have  been  led  by 
our  examinations  of  dried  specimens,  as  we  have 
not  been  so  fortunate  as  to  obtain  living  ones, 
since  the  commencement  of  these  observations, 
is,  that  every  nervure  contains  a  distinct  tra- 
cheal or  air-bearing  vessel,  and  that  the  free 
transparent  space  by  which  it  is  surrounded, 
and  which  is  not  discoverable  by  the  naked 
eye,  but  only  by  the  microscope,  constitutes 
alone  the  proper  circulatory  passage ;  that  the 
trachea;,  which  are  obvious  to'  the  naked  eye, 
do  not  simply  lie  loosely  in  these  spaces,  but 
that  the  spaces  lie  chiefly  at  their  sides  and 
under-surface.  These  opinions  have  been  de- 
rived from  examinations  of  transverse  sections 
of  the  wings  of  the  Chrt/sopa,  at  parts  in  which, 
on  a  previous  examination  of  the  surface  of 
the  wing,  we  have  seen  both  trachea?  and  the 
spaces  around  them.  On  cutting  the  wing 
across  at  these  parts,  and  then  examining  the 
edges,  we  have  invariably  found  the  trachea? 
hollow,  unyielding  tubes,  while  the  free  spaces 
on  each  side,  which  appear  as  if  bounded  by 
the  upper  and  under  membrane  of  the  wing, 
have  appeared  collapsed,  and  almost  or  com- 
pletely closed,  so  as  scarcely  to  exhibit  any 
appearance  of  hollow  spaces.  On  examining 
the  wing  of  a  dried  specimen  of  one  of  the 
Lepidoptera,  Gonepteryx  Rhamni,  by  trans- 
verse sections,  we  have  in  every  instance  found 
the  nervures  formed  of  hollow  unyielding  tubes, 
with  all  the  characters  of  true  tracheal  vessels, 
but  have  not  been  able  to  detect  the  proper 
circulatory  spaces  at  the  sides  of  these  nervures, 
most  probably  owing  to  their  dried  and  col- 
lapsed state.  From  these  facts  we  are  led  to 
express  an  opinion  which  has  been  long  enter- 
tained by  us,  that  the  course  of  the  blood, 
whether  simply  along  intercellular  spaces,  or 
bounded  by  distinct  vessels,  is  almost  inva- 
riably in  immediate  connexion  with  the  course 
of  the  tracheae.  This  opinion  is  founded  upon 
the  circumstance  that  nearly  all  the  observations 
that  have  hitherto  been  made  have  shown  that  the 
currents  of  blood  in  the  body  of  an  insect  are 
often  in  the  vicinity  of  the  great  tracheal  vessels, 
both  in  their  longitudinal  and  transverse  direc- 
tion across  the  segments,  and  it  is  further  strength- 
ened by  Mr.  Bo wei bank's  observations  on  the 
course  of  the  blood  in  the  wings.  During  his 
observations  Mr.  Bowerbank  observes  that  he 
"  has  used  every  endeavour  to  discover,  if  pos- 
sible, whether  the  blood  has  proper  vessels,  or 
only  occupied  the  internal  cavities  of  the  ca- 
nals ;  and  that  he  is  convinced  that  the  latter  is 
the  case,  as  he  could  frequently  perceive  the 
particles  not  only  surrounding  all  parts  of  the 
trachea;,  and  occupying  the  whole  of  the  in- 
ternal diameter  of  the  canals,  but  it  frequently 
happens  that  globules  experienced  a  momen- 
tary stoppage  in  their  progress,  occasioned  by 
their  friction  against  the  curved  surface  of  the 
tracheae,  which  sometimes  gave  them  a  rotatory 
motion."  He  remarks  also  that  the  usual  course 
of  the  blood  through  the  canals  is  in  one  conti- 
nued stream,  without  pulsatory  motion,  ex- 
cepting only  when  the  insect  under  examination 
is  struggling  to  escape,  when  the  continuity  of 
the  stream  is  broken,  and  there  are  occasional 
oscillations,  of  which  he  observed,  in  one  in- 


CTA.  981 

stance,  in  a  vessel  within  a  space  or  about  one- 
fiftieth  of  an  inch,  twenty-one  oscillations  in  a 
minute ;  and  in  another,  in  the  same  space,  so 
many  as  eighty-four.  He  observed  also  in  in- 
sects that  had  been  captured  and  in  confine- 
ment for  several  days,  that  the  motions  of  the 
fluid  became  exceedingly  languid  and  almost 
entirely  ceased.  The  se  observations  are  exceed- 
ingly interesting  in  reference  to  the  genera! 
velocity  of  the  circulation,  and  the  means  by 
which  it  is  carried  on  in  the  wings.  The  entire 
absence  of  pulsations  is  remarkable,  as  it  com- 
pletely identifies  these  vessels  as  veins,  since  it 
is  well  known  that  the  circulation  is  carried  on 
through  the  body  by  means  of  regular  pulsa- 
tions of  the  dorsal  vessel.  The  number  of  these 
latter  pulsations  varies  greatly  in  different  insects. 
Thus  llerold  found  from  thirty  to  forty  in  a  minute 
in  a  full-grown  caterpillar,  and  from  forty-six  to 
forty-eight  in  a  mucli  younger  one;  Suckow  ob- 
served but  thirty,  in  the  same  space  of  time,  in  a 
full-grown  caterpillar  of  Qastropacha  pini,  and 
eighteen  only  in  its  pupa  state.  But  in  one  in- 
stance, when  the  insect  was  in  a  state  of  the  most 
violent  excitement,  we  have  counted  one  hundred 
and  forty-two  in  a  female  of  Anthophora  re- 
turn. In  a  number  of  these  insects  captured 
just  after  they  had  left  their  hybernacula  in  the 
month  of  April,  and  confined  for  some  time  in 
a  breeding-cage,  we  have  found  that  the  num- 
ber of  pulsations  varies,  as  might,  a  priori,  be 
supposed,  according  to  their  state  of  excite- 
ment. Thus  on  exposing  the  dorsal  vessel  in 
the  morning,  before  the  insects  had  been  excited, 
we  found  the  number  of  pulsations  was  about 
eighty  per  minute ;  at  ten  o'clock,  when  they 
had  become  active,  the  number  of  pulsations 
ranged  from  one  hundred  to  one  hundred  and 
ten ;  but  at  three  o'clock  in  the  afternoon,  when 
the  insects  were  quite  lively,  and  had  been 
exposed  to  the  sun  for  an  hour  or  two,  the 
number  of  pulsations  amounted  to  one  hundred 
and  forty;  while  on  another  occasion,  on  a  cold 
dull  morning,  when  the  bees  were  languid,  the 
number  of  pulsations  did  not  exceed  seventv- 
five  in  any  specimen  that  was  examined.  It 
has  usually  been  supposed,  since  the  discovery 
of  a  circulation  in  insects,  that  the  pulsations 
are  more  frequent  in  the  larva  than  the  perfect 
state ;  but  this  certainly  is  not  the  case,  if  the 
mean  number  of  observations  in  the  two  states 
be  compared.  Thus  in  a  series  of  observations 
made  by  us  on  the  Sphinx  ligustri,*  from  the 
fourth  day  after  the  larva  had  left  the  egg  until 
the  perfect  insect  was  developed,  it  was  found 
that  before  the  larva  cast  its  first  skin  the  mean 
number  of  pulsations,  in  a  state  of  moderate 
activity  and  quietude,  was  about  eighty-two  or 
three  per  minute  ;  before  casting  its  second  skin 
eighty-nine  ;  while  before  casting  its  third  it 
had  sunk  down  to  sixty-three  ;  and  before  its 
fourth  to  forty-five,  while  previously  to  leaving 
its  fourth,  and  before  it  had  ceased  to  feed,  pre- 
paratory to  entering  the  pupa  state,  it  was  not 
more  than  thirty-nine.  Thus  the  number  gra- 
dually decreases  during  the  growing  larva  state, 
but  the  force  of  the  circulation  is  very  much 
augmented.    Now  when  the  insect  is  in  a  state 

*  Phil.  Trans,  p.  2,  1837. 


982 


INSECT  A. 


of  perfect  rest,  previously  to  changing  its  skin, 
the  number  is  pretty  nearly  equal  at  each  pe- 
riod, being  about  thirty.  When  the  insect 
has  passed  into  the  pupa  state  it  sinks  down  to 
twenty-two,  and  subsequently  to  ten  or  twelve, 
and  after  that,  during  the  period  of  hybernation, 
it  almost  entirely  ceases.  But  when  the  same 
insect  which  we  had  watched  from  its  earliest 
condition  was  developed  into  the  perfect  state 
in  May  of  the  following  spring,  the  number  of 
pulsations,  after  the  insect  had  been  for  some 
time  excited  in  flight  around  the  room,  amounted 
to  from  one  hundred  and  ten  to  one  hundred 
and  thirty-nine;  and  when  the  same  insect  was 
in  a  state  of  repose,  to  from  forty-one  to  fifty. 
When,  however,  the  great  business  of  life,  the 
continuation  of  the  species,  has  been  accom- 
plished, or  when  the  insect  is  exhausted,  and 
perishing  through  want  of  food  or  other  causes, 
the  number  of  pulsations  gradually  diminishes, 
until  the  motions  of  the  heart  are  almost  im- 
perceptible. Insects,  then,  do  not  deviate  from 
other  animals,  as  has  been  supposed,  in  re- 
gard to  their  vital  phenomena,  although  it  has 
been  somewhat  curiously  imagined  that  the 
nutrient  and  circulatory  functions  are  less 
active  in  the  perfect  than  in  the  larva  condition. 
This  supposed  inferiority  has  been  attempted 
to  be  accounted  for  on  the  hypothesis  that  as 
insects  no  longer  increase  in  size  after  entering 
the  perfect  state,  there  is  but  little  expendi- 
ture or  waste  of  body,  and  that,  consequently, 
they  must  require  less  nourishment.  But  we 
have  elsewhere  shown  *  that  the  expenditure  of 
the  body,  whether  in  the  larva  or  perfect  state, 
is  in  the  ratio  of  the  amount  of  activity  and 
length  of  life  of  the  insect,  while  it  will  be 
remembered  that  those  insects  which  exist  but 
for  a  short  time  in  the  perfect  state,  and  take 
little  or  no  food,  invariably  have  a  supply 
of  nourishment  stored  up  within  their  own 
bodies,  in  immense  accumulations  of  adipose 
matter;  and  that  those  which  exist  for  a  lona; 
period  have  within  themselves  only  a  small 
quantity  of  nourishment,  but  are  by  no  means 
sparing  in  the  quantity  of  food  daily  consumed 
by  them,  being,  as  they  often  are,  some  of  the 
most  voracious  of  the  insect  race. 

Organs  of  respiration. — All  perfect  insects, 
whether  inhabitants  of  air  or  water,  breathe  air 
alone;  but  some  larva?,  that  are  constant  in- 
habitants of  water,  respire  the  air  which  is  me- 
chanically mixed  with  the  water,  by  means  of 
branchias ;  but  respiratory  organs  in  the  form  of 
trachea;  (fig.  435)  are  almost  as  extensively 
distributed  throughout  every  part  of  their  bodies 
as  in  the  perfect  insects.  We  shall  divide  the 
respiratory  organs  into  external  and  internal. 
The  external  are  of  three  kinds,  spiracles,  tra- 
chea, and  branchia.  The  internal  are  either 
simply  tracheal,  or  tracheal  and  vesicular. 

The  spiracles  are  apertures  situated  along  the 
sides  of  the  body  communicating  directly  with 
the  internal  respiratory  organs.  They  are 
usually  nine  in  number  on  each  side.  In  Hy- 
menopterous  larva?  there  are  ten.  Each  spi- 
racle consists  of  a  horny  ring,  generally  of  an 
oval  form,  within  which  is  a  valve  formed  of  a 

*  Phil,  Trans,  p.  2,  1837, 


Fig.  435. 


Portion  o  f  a  tracfseal  vessel  of  the  larva  of  Vanessa 
■urticce,  shewing,  a,  the  spiral  fibre  j  and  b,  the 
loose  investing  covering.     (Netvport,  Phil.  Trans.y 

series  of  converging  fibres,  and  which  opens 
perpendicularly  in  its  long  axis,  guarding  the 
external  entrance.  At  a  little  distance  within 
this  valve  the  spiracle  is  somewhat  enlarged, 
and  there  is  a  second  valve  of  a  more  com- 
plicated form.  This  has  already  been  noticed 
in  our  account  of  the  muscular  structure,  but 
we  must  again  describe  it  in  connexion  with  the 
respiratory  organs.  The  anterior  half  of  this 
inner  or  second  valve  is  strong,  immovable, 
and  of  a  horny  texture,  of  the  colour  of  tortoise- 
shell.  It  is  thin  and  lunated  at  its  margin. 
The  posterior  half  is  thick,  rounded,  and  freely 
moveable,  and  closes-  on  the  anterior  like  a 
cushion  or  pad.  This  is  the  structure  of  the 
spiracle  in  the  Sphinx  and  most  other  insects. 
But  m  some,  in  which  the  spiracle  is  concealed 
beneath  a  portion  of  the  skeleton,  the  horny 
external  ring  is  absent,  and  instead  of  it  the 
entrance,  or  margin  of  the  spiracle,  is  merely  a 
little  thickened  and  fringed  with  short  hairs. 
This  description  of  spiracle  exists  in  the  pro- 
thorax  of  some  Coleoptera  and  Orthoptera 
as  in  Gryllolalpa,  in  which  one  portion  or  lip 
overlaps  the  other,  thus  forming  as  it  were  an 
outer  valve  or  lid.  In  other  instances,as  in  the 
Lamellicornes,  the  spiracles  of  the  abdomen 
are  very  minute  and  circular,  and  their  open- 
ing appears  to  be  cribriform,  or  at  most  only 
very  minute,  and  surrounded  by  short  hairs. 
In  others,  again,  as  in  some  larvae,  the  spiracles 
consist  of  a  broad  margin  with  a  narrow 
middle  space  and  central  aperture  that  leads 
immediately  into  the  tracheal  vessel,  the  open- 
ing into  which  is  exceedingly  small.  The  size 
of  the  spiracles  in  different  parts  of  the  body 
varies  very  much  in  different  insects.  Those 
of  the  abdomen  are  always  much  smaller  than 
those  of  the  thorax,  and  the  most  posterior  ones, 
which  were  of  great  importance  in  the  larva 


INSECTA. 


933 


state,  are  almost  or  entirely  imperforate  in  the 
perfect.  The  reason  for  this  appears  to  result 
from  the  changes  that  take  place  as  regards 
the  region  of  the  body  in  which  respiration 
is  chiefly  carried  on  in  the  two  states  of 
the  insect.  In  the  larva  state  respiration  is 
carried  on  chiefly  in  ihe  abdominal  region,  but 
in  the  perfect  the  chief  part  of  the  body  con- 
cerned is  the  thorax.  It  is  through  the  tho- 
racic and  first  pair  of  abdominal  spiracles  that 
nearly  the  whole  of  the  air  enters  and  is  ex- 
pired at  each  act  of  respiration,  and  conse- 
quently it  is  found  that  the  spiracles  in  those 
parts  are  very  much  larger  than  in  the  abdo- 
men. The  largest  spiracle  is  usually  the  pro- 
thoracic,  of  which  we  have  an  example  in 
Geotritpes  and  Gryllotalpa,  and  the  next 
Largest,  as  in  Geotrupes,  is  the  first  abdominal. 
The  situations  in  which  the  spiracles  are  placed 
also  vary  considerably  in  different  insects.  In 
Coleoptera  and  Orthoptera  the  first  pair  are  si- 
tuated in  the  membrane  between  the  pro-  and 
meso-thorax,  and  the  remaining  ones  in  the 
meso-*  and  meta-thorax  and  following  seg- 
ments of  the  abdomen.  There  is  also  a  similar 
arrangement  of  the  spiracles  in  Hemiptera. 
But  in  other  insects,  as  in  the  larvae  of  Lepi- 
doptera,  the  first  spiracle  is  situated  in  the  pro- 
thorax,  and  the  remaining  eight  pairs  in  the 
fifth  and  succeeding  segments  to  the  twelfth  ; 
while  in  the  larvae  of  Hymenoptera,  in  which 
there  are  ten  spiracles  on  each  side,  they  are 
placed  in  the  second,  third,  fifth,  sixth,  and 
succeeding  segments  to  the  twelfth. 

The  second  form  of  external  respiratory  or- 
gans, as  Burmeister  remarks,  are  simply  elon- 
gated spiracles,  and  are  found  only  in  those 
insects  which  reside  almost  constantly  in  the 
water,  but  breathe  pure  atmospheric  air,  for 
which  purpose  they  come  to  the  surface  of  the 
water  at  intervals  to  respire.  They  are  short 
horny  tubes,  which  in  some  instances  are  sur- 
rounded by  plumose  setae.  They  are  always 
open  at  their  extremity,  and  in  general  project 
beyond  the  body.  They  are  chiefly  met  with 
in  the  aquatic  Hemiptera,  as  in  Nepa  (Jig. 
352)  and  Runatra,  and  are  usually  two  in 
number,  projecting  from  the  extremity  of  the 
abdomen.  In  Nepa  they  are  about  half  the 
length  of  the  body,  and  in  Ranatra  as  long  as 
the  whole  body  itself.  It  is  through  these 
tubes  that  the  whole  of  the  respiratory  function 
is  performed,  and  the  air  both  inspired  and  ex- 
pelled. They  exist  also  in  the  larvae  of  the 
Dyticida  and  Hydrophilida:,  in  which  they 
are  the  only  respiratory  passages,  although  it 
has  been  thought  by  some  that  lateral  spiracles 
exist  also  in  these  larvae,  as  subsequently  found 
in  their  perfect  insects.  This  form  of  respira- 
tory organ  exists  also  in  the  aquatic  larvae  of 
some  Diptera,  as  in  the  rat-tailed  maggot, 
Eristalis,  and  the  larva  of  Stratiornys.  In  the 
latter  instance  the  insect  supports  itself  at  the 
surface  of  the  water  by  a  coronet  of  radiating 
setae,  in  which  it  includes  a  bubble  of  air,  and 
descends  with  it  to  the  bottom  of  pools  for 
the  purposes  of  respiration,  and  comes  again 

*  Straus. 


to  the  surface  for  a  fresh  supply  when  the  store 
it  has  carried  with  it  is  exhausted.  These  or- 
gans are  thus  distinct  from  those  by  means  of 
which  the  insects  respire  the  air  mechanically 
mixed  with  the  water. 

Branchia  constitute  the  third  form  of  ex- 
ternal respiratory  organ.  This  form  is  met 
with  only  in  the  larva  and  pupa  state.  These 
organs  are  always  situated  at  a  part  of  the  body 
at  which  the  spiracles  are  subsequently  to  exist. 
They  are  formed,  as  in  the  larvae  of  Amphibiae,  of 
extensions  outwards  of  the  exterior  or  cuticular 
surface  of  the  body,  and  are  largely  supplied 
with  bloodvessels,  and  tracheae  ramify  within 
them.  They  are  never,  as  in  the  gills  of  fishes, 
developed  internally,  excepting  when  they  exist 
at  the  anal  extremity  of  the  body,  as  in  the 
Libellulidce,  but  are  extended  from  the  sides  as 
in  the  Tadpole,  being  simply  expansions  of  the 
external  surface.  We  are  not  aware  that  cilia 
have  yet  been  observed  on  these  surfaces,  but 
judging  from  the  analogies  of  structure  and 
formation  that  exist  between  these  parts  in 
insects  and  the  analogous  ones  in  the  larvae  of 
Amphibia,  there  seems  reason  to  expect  that 
they  do  probably  exist.  The  necessity  for  such 
structures  on  the  branchiae  may,  however,  be 
rendered  less  imperative  from  the  voluntary 
power  which  the  insect  itself  possesses  of 
moving  the  branchiae  at  pleasure,  by  which 
the  function  of  cilia,  that  of  effecting  a  con- 
stant renewal  of  the  water  in  contact  with  the 
surface  of  the  organ,  is  steadily  accomplished. 
It  is  the  belief  of  most  entomologists,*  that 
branchiae  absorb  the  air  from  the  water,  and 
convey  it  by  the  minute  ramifications  of  the 
tracheal  vessels,  with  which  they  are  abundantly 
supplied,  and  which  terminate  in  single  trunks, 
into  the  main  tracheae,  to  be  distributed  over 
the  whole  body,  as  in  insects  which  live  in  the 
open  atmosphere.  This  is  supported  by  the 
fact  that  the  tracheal  vessels,  as  seen  in  the 
transparent  bodies  of  many  aquatic  larvae,  are 
filled  with  air;  but  the  subject  still  admits  of 
enquiry,  why  in  these  instances  the  usual  func- 
tion of  branchiae  is  so  far  departed  from  as  to 
allow  of  the  air  being  absorbed  from  the  water 
into  distinct  vessels,  to  be  distributed  over  the 
whole  body,  for  the  purpose  of  aerating  the 
fluids,  rather  than  that  it  should  be  brought 
into  contact  with  the  blood,  and  undergo  the 
consequent  changes  at  the  surface  of  the  bran- 
chiae, as  in  the  larvae  of  Amphibia  and  Fishes. 

The  branchiae  of  insects  are  of  three  kinds. 
The  first  exists  in  the  form  of  elongated, 
slender,  hair-like  organs,  collected  together  in 
tufts,  that  originate  by  single  stems,  as  in  the 
larvae  and  pupae  of  gnats.f  This  form  is  by  far 
the  most  common.  These  filamentous  parts 
are  supplied  each  with  a  single  trachea  that  is 
extended  throughout  their  whole  length,  and 
which  is  connected  with  the  great  longitudinal 
tracheae  of  the  body.  In  a  very  few  instances, 
branchiae  of  this  form  originate  separately,  and 
not  in  tufts,  as,  according  to  De  Geer,|  in  the 

*  Burmeister. 

t  Burmeister,  op.  cit.  p.  167. 
X  Mcmoires  sur  les  Inscctcs,  vol.  iv.   pi.  13, 
fig.  16.19. 


984 


INSECTA. 


larva?  of  Gyrinidte,  in  which  they  are  arranged 
along  the  sides  of  each  segment  as  short  stiff 
bristles.  This  form  of  branchia?  is  also  said  to 
exist  in  one  solitary  species  of  Lepidoptera, 
Hydrocampa  straiiotata,*  and  perhaps,  also, 
in  the  other  species  of  the  same  genus,  in 
which  branchia?  of  this  form  exist  in  the  neigh- 
bourhood of  false  spiracles. 

The  second  kind  of  branchiae  exists  in  the 
form  of  flat,  oval,  or  lanceolate  plates,  extended 
from  the  sides  of  each  segment  of  the  abdo- 
men, where  spiracles  afterwards  exist  in  the 
perfect  insect.  In  some  instances,  as  in  the 
AgrionidtB,  these  plates  exist  only  at  the  extre- 
mity of  the  abdomen.  In  others,  as  in  the 
Ephemerida,  they  exist  both  at  the  sides  and  at 
the  extremity  of  the  body.  This  form  of 
branchiae  is  found  only  in  the  Neuroptera  and 
Triclioplera.  In  many  of  the  latter  instances 
these  parts  possess  also  the  additional  function 
of  being  the  chief  locomotive  organs  of  the 
insect,  and  remind  us  strongly  of  the  branchi- 
form  organs  of  locomotion  in  the  post-abdo- 
men of  many  Crustacea. 

An  anomalous  insect,  recently  discovered  by 
Mr.  Hogg  as  a  constant  inhabitant  of  the  river- 
sponge,  and  an  account  of  which  was  read  by 
Mr.  Westwood  at  a  meeting  of  the  Entomolo- 
gical Society  on  the  3rd  of  December,  1838, 
possesses  a  third  and  most  remarkable  descrip- 
tion of  branchia.  This  insect,  which  was  re- 
ferred by  Mr.  Westwood  to  the  order  Neurop- 
tera, genus  Acentropus,  Steph.  very  much 
resembles  the  larva  of  a  neuropterous  species, 
and  has  filiform  branchiae  extended  from  the 
sides  of  the  abdomen,  which  are  distinctly  ar- 
ticulated, and  apparently  five-jointed.  Mr. 
Westwood  informs  us  that  he  has  distinctly 
traced  tracheae  into  the  branchia?,  and  that  the 
open  extremity  of  each  vessel  protrudes  from 
the  tip  of  the  branchiae,  so  that  in  this  respect 
these  organs  resemble  elongated  spiracles. 

Very  few  of  those  larva?  or  pupa?  that  pos- 
sess branchia?  have  any  lateral  spiracles,  ex- 
cepting the  Culicida.  In  some  of  these,  as  in 
the  common  Gnat,  both  larva?  and  pupa?  breathe 
by  means  of  large  tracheal  vessels,  extended 
outwards  to  some  distance  from  the  head  and 
thorax,  while  the  body  is  also  furnished  with 
filamentous  branchia?.  The  larva  of  Chiro- 
nomus,  remarkable  for  its  blood-red  colour,  and 
which  breathes  through  tubes,  is  furnished  in 
its  pupa  state  with  branchia?  f  at  a  part  cor- 
responding to  that  at  which  the  first  spiracles 
are  to  appear  in  the  perfect  insect.  The  true 
Libelluiida  have  neither  lateral  nor  anal  bran- 
chia?, but,  according  to  Suckow  and  others, 
breathe  by  means  of  branchia?  in  the  colon. 
But  in  these  insects,  as  in  the  Ephemerida. 
with  lateral  branchia?,  the  acts  of  respiration  are 
also  those  of  progression ;  since,  although  the 
imbibition  and  expulsion  of  water  at  the  anal 
extremity  are  regular  and  constant,  even  when 
the  insect  is  remaining  perfectly  quiet,  they  are 
increased  both  in  number  and  force  at  every 
act  of  locomotion,  and  carry  the  body  forward 

*  Id.  vol.  i,  pi.  xxxvii. 
t  Burmeistcr,  p.  167. 


by  darts  or  sudden  impulses.  The  water  is 
received  at  the  anal  orifice  by  an  inspiratory  or 
sucking  action,  as  proved  by  the  circumstance 
that  small  particles  of  substances  floating  in 
the  water  are  drawn  in  with  the  stream  at  the 
anus  at  each  inspiration,  and  again  expelled 
from  it  when  the  water  is  ejected,  and  this  oc- 
curs with  the  greatest  regularity.  The  cavity 
into  which  the  water  is  received  is  a  clouca 
distinct  from  the  proper  alimentary  canal,, 
analogous  to  the  respiratory  cloaca  of  the  Ho- 
lothuria  and  other  lower  invertebrata. 

These  external  organs  of  respiration  all  com- 
municate with  elongated  trachea?,  from  which 
are  distributed  other  branches  over  the  internal 
structures.  In  the  larva?  of  all  insects  these 
internal  respiratory  organs  are  simply  ramified 
tubes,  but  in  perfect  insects,  and  more  parti- 
cularly in  volant  species,  these  tubes  are  di- 
lated into  an  immense  number  of  minute 
vesicles,  which  not  only  allow  of  the  most  ex- 
tensive respiration,  but  also  render  the  body 
lighter,  by  enabling  the  insect  to  alter  its  spe- 
cific gravity  during  flight.  In  all  insects  the 
vesicles  are  only  dilated  trachea?,  the  structure 
of  which  is  the  same  throughout  the  class.  In 
the  larva  of  the  Sphinx  and  other  insects  the 
tracheal  vessels  consist  of  two  elongated  tubes, 
extended  one  on  each  side  of  the  body,  and 
which  on  their  external  side  communicate  by 
very  short  tubes  with  the  spiracles,  and  on  their 
opposite,  towards  the  middle  line  of  the  body, 
give  off  near  each  spiracle  a  large  tuft  of  ves- 
sels, about  twelve  in  number,  which  extending 
inwards  are  distributed  over  the  different 
organs  within  the  body.  The  chief  of  these 
are  distributed  to  the  alimentary  canal,  while 
others  pass  upwards  among  the  muscles,  and 
ramify  most  extensively  between  them,  and  are 
given  in  great  abundance  to  the  dorsal  vessel. 
In  every  segment  other  branches  are  extended 
to  the  median  line  above  the  vessel,  and  anas- 
tomose with  corresponding  branches  from  the 
opposite  side  of  the  segment.  In  the  head  one 
large  branch  passes  forwards  from  the  pro- 
thoracic  spiracle,  and  anastomoses  with  its 
fellow  from  the  opposite  side  above  the  oeso- 
phagus, behind  the  brain,  and  the  two  thus 
united  then  give  off  four  branches,  which 
passing  forwards  over  the  brain  give  off  branches 
that  ramify  on  the  surface,  and  even  in  the 
substance  of  that  organ  and  of  the  optic 
nerves.  Other  branches  are  given  to  the 
muscles  of  the  head,  the  future  antenna?,  and 
the  organs  of  manducation.  On  the  under 
surface  of  the  body  the  tracheal  vessels  dis- 
tribute themselves  among  the  muscles,  as  on 
the  dorsal  surface,  some  passing  beneath  the 
nervous  cord  to  anastomose  with  those  from  the 
opposite  side,  while  others  are  distributed  to, 
and  ramify  extensively  over  the  surface  of  each 
gangliated  portion  ofthe  cord,  givingoff  the  most 
minute  branches  which  penetrate  the  very  sub- 
stance of  the  ganglia  (fig.  415,  i,  i),  and  also 
that  of  the  nerves  themselves,  along  which  other 
minute  branches  are  extended,  so  that  even  the 
most  important  and  delicate  organs  of  the 
body  are  plentifully  supplied  with  tracheal 
vessels.    Other  branches  of  trachea?  also  pass 


1NSECTA. 


985 


between  the  fibres  of  the  muscular  coat  of  the 
alimentary  canal,  and  ramify  extensively  be- 
tween the  mucous  coat  and  a  structure  which  we 
have  described*  as  the  adipose  coat,  which  lies 
between  the  mucous  and  muscular,  as  is  well 
seen  in  the  colon  and  coecum  of  the  puss-moth, 
Ceri/ra  vinula,  in  the  perfect  state.  It  is  in 
this  layer  that  the  ramifications  of  tracheae 
anastomose  very  freely,  but  do  not  enter  the 
mucous  or  internal  coat.  Besides  these  parts 
all  the  secretory  and  generative  organs  are  sup- 
plied with  anastomosing  branches  in  abun- 
dance, and  trachea;  are  extended  even  to  the 
very  last  joints  of  the  tarsi  in  the  limbs.  The 
only  parts  into  which  we  have  not  observed 
tracheae  penetrate  are  the  adipose  vesicles, 
upon  which  we  have  not  often  observed  rami- 
fications, although  branches  of  tracheae  are  dis- 
tributed very  extensively  among  them.  In  the 
larva  state  the  tracheae  are  always  smaller  than 
in  the  perfect,  compared  with  the  size  of  the 
individual,  and  they  are  smallest  in  those 
apodal  larvae  of  Hymenoptera  which  reside 
long  in  closed  cells,  as  the  Anthophura  return, 
in  which  insect  the  communications  of  the 
tracheae  across  the  body  are  very  distinct,  as 
was  shewn  long  ago  by  Swammerdam  in  the 
larva  of  the  hive-bee. 

The  structure  of  the  tracheae  has  been  des- 
cribed by  Swammerdam,  Sprengel,  and  others. 
Sprengel  has  described  the  structure  as  con- 
sisting of  an  external  serous  and  an  internal 
mucous  membrane;  inclosing  between  them  a 
spirally  convoluted  fibre  (fig. 435,  a),  which  is 
elastic,  and  gives  to  the  tracheae  the  appearance 
exhibited  by  the  tracheae  in  other  animals. 
The  external  or  serous  membrane  (b)  very 
loosely  surrounds  the  spiral  fibre  («).  The 
mucous  or  internal  lining,  as  we  formerly  re- 
marked, and  as  noticed  by  Swammerdam,  De 
Geer,  Lyonet,  and  Bonnet,  is  continuous  with, 
and  is  thrown  off' at  the  change  with  the  external 
covering  of  the  larva,  and  certainly  is  a  distinct 
membrane,  renewed  at  those  periods,  although 
Sprengel  believes  that  it  is  only  a  means  of 
connexion  between  the  coils  of  the  spiral  fibre, 
and  not  a  distinct  structure. 

The  vesicles,  or  dilated  tracheae,  exist  in  the 
greatest  abundance  in  volant  insects,  although 
they  also  exist  in  a  much  less  developed  form 
in  the  saltatorial.  These  vesicles  exhibit  an 
appearance  which  was  formerly  noticed  by 
Swammerdam  in  Ori/ctes  nasicornis,  and  sub- 
sequently by  Sprengel  in  other  insects.  It  con- 
sists of  an  amazing  number  of  punctured  spots, 
discoverable  only  under  a  good  microscope,  but 
which,  when  attentively  examined,  exhibit 
somewhat  the  appearance  of  perforations.  The 
precise  nature  of  these  spots  is  not  well  under- 
stood. Burmeister  conceives  that  they  are  oc- 
casioned by  the  rupture  of  the  spiral  fibre 
during  development,  and  that  the  spots  are  the 
spaces  between  the  broken  fibres.  But  Marcel 
de  Serres  and  Straus  Durckheim  deny  the 
existence  of  spiral  fibre  in  the  vesicles,  while 
Suckow  and  Burmeister  contend  that  it  cer- 
tainly  does  exist,  and  we  also  are  of  this 

»  Phil.  Tians.  1836. 


opinion.  Indeed,  when  it  is  remembered  that 
the  vesicles  exist  only  in  the  perfect  insect,  and 
are  only  dilated  tracheae,  and  that  the  existence 
of  spiral  fibre  in  the  tracheae  is  undoubted, 
surely  its  existence  can  scarcely  be  questioned 
in  the  vesicles,  although,  probably,  it  is  in  an 
almost  atrophied  condition.  Now  the  fact  that 
the  spots  are  not  observed  on  the  vesicles 
until  the  insect  has  entered  the  perfect  state, 
was,  perhaps,  one  of  the  circumstances  that 
led  Burmeister  to  his  opinion  respecting  them  ; 
but  that  they  are  not  caused  by  ruptured  spiral 
fibre  is  proved  by  the  existence  of  these  spots 
in  some  of  the  tracheae  that  communicate  direct- 
ly with  the  vesicles,  and  have  not  been  dilated, 
and  in  which  the  spiral  fibre  is  unbroken.  It 
is  also  shewn  by  the  circumstance  of  their  not 
being  in  a  regular  series,  over  the  course  of  the 
fibres,  but  distributed  thickly  and  irregularly 
over  the  surface  of  the  vesicles,  and  by  their 
existing  in  the  space  between  two  parallel 
fibres  in  the  tracheae,  and  even  in  the  substance 
of  the  fibre,  as  we  have  seen  them  in  the 
vesicles  of  the  male  of  Bombus  terrestris.  Be- 
sides this,  they  are  sometimes  seen  to  terminate 
in  an  abrupt  and  remarkable  manner  in  the 
dilatations  of  the  larger  tracheae  in  the  same 
insect.  The  results  of  our  own  observations 
lead  us  to  conclude  that  these  spots  are  not 
ruptures  of  the  spiral  fibre,  but  are  partial  per- 
forations of  the  vesicles, — that  they  do  not 
pass  through  the  internal  or  lining  coat,  and 
probably  are  little  cells  in  the  coats  of  the  vesi- 
cles, through  which  the  circulatory  fluid  can  be 
freely  submitted  to  the  action  of  the  air  in  the 
vesicles,  as  in  the  minute  terminal  cells  in  the 
lungs  of  vertebrata. 

The  use  of  the  vesicles,  as  above  remarked, 
and  as  formerly  suggested  by  Hunter,  appears 
to  be  to  enable  the  insect  to  alter  its  specific 
gravity  at  pleasure,  by  enlarging  its  bulk,  and 
thus  rendering  it  better  able  to  support  itself  on 
the  wing  with  little  muscular  effort.  That  this 
is  the  use  of  the  sacs  may  be  inferred  from 
their  non-existence  in  the  larva  state,  or  in  in- 
sects that  constantly  reside  on  the  ground,  more 
particularly  in  creeping  insects  ;  and  it  seems 
further  confirmed  by  the  fact  that,  among  volant 
insects,  those  have  the  largest  and  greatest 
number  of  vesicles  which  sustain  the  longest 
and  most  powerful  flight.  Thus  the  vesicles 
are  found  most  developed  in  the  Hymenoptera, 
Lepidoptera,  Diptera,  ;ind  some  Coleoptera  and 
Hemiptera,  in  all  which,  in  the  larva  state,  there 
is  not  the  slightest  trace  of  them.  A  still 
further  proof  that  they  are  for  lightening  the 
body  is  found  in  Lucanus  cervus.  In  the 
male  of  this  insect  the  large  and  heavy  man- 
dibles and  head,  but  more  especially  the  man- 
dibles, are  not  filled  with  solid  muscle,  as  in 
the  Hydrous  and  others  in  which  these  parts 
are  more  in  proportion  to  the  size  of  other 
parts  of  the  body,  but  with  an  immense 
number  of  vesicles,  which  in  the  mandibles 
are  developed  in  the  greatest  abundance  in 
rows  from  long  tracheae,  that  are  extended 
from  one  end  of  the  organ  to  the  other,  so  that 
the  interior  is  almost  entirely  filled  with  vesi- 
cles.   By  this  beautiful  provision  these  pro- 


986 


INSECTA. 


jecling  and  apparently  unwieldy  structures 
are  rendered  exceedingly  light,  while  their 
solid  exterior  fits  them  for  all  the  purposes  of 
strength  required  by  the  insect.  The  large  and 
apparently  heavy  body  of  the  humble-bee  is 
lightened  in  a  similar  manner.  In  this  insect 
and  others  of  the  same  order,  the  vesicles  are 
fewer  but  very  much  larger  than  in  Coleoptera. 
The  lateral  trachea;  in  the  abdomen  form  one 
continuous  chain  of  dilatations,  which  are 
larger  in  the  males  of  the  species  (fig.  436) 

Fig.  436. 


The  lateral  and  inferior  series  of  vesicular  respi- 
ratory organs  in  the  abdomen  of  a  male  individual  of 
Bombus  terrestris.   (  Newport,  Phil.  Trans. ) 


than  in  the  females.  The  longitudinal  tra- 
chea (a),  that  pass  backwards  from  the 
thoracic  region,  are  connected  just  as  they 
pass  through  the  petiole  or  thoracico-abdo- 
minal  segment  into  the  abdomen,  by  a  very 
short  transverse  branch  (/>),  which  gives  off 
two  pairs  of  minute  branches  into  the  ab- 
domen. The  longitudinal  trachea?  (c)  pur- 
suing their  course  onwards  are  dilated,  soon 
after  they  enter  the  large  first  segment  of  the 
abdomen,  into  two  enormously  expanded 
vesicles  (_/'),  above  which  is  placed  transversely 
a  third  and  much  larger  one,  which  is  formed 
from  the  anastomosing  branches  of  the  opposite 
sides  of  the  segment,  and  is  also  connected 
with  the  little  branches  given  off  from  the 
transverse  branch  (b).  Beneath  this  large 
vesicle  passes  the  dorsal  vessel,  and  between 
the  tv.  o  lateral  ones  (f)  the  alimentary  canal. 
Besides  the  branches  from  the  transverse  tracheae 
(6)  there  are  two  others  from  the  large  tra- 
cheae (e),  which  pass  longitudinally  backwards, 
one  on  each  side  of  the  oesophagus.  That  on 
the  left  side  (e,  e)  passes  as  far  as  the  posterior 


part  of  the  proventriculus,  and  then  turning 
forwards  distributes  its  branches  to  that  organ. 
The  other  on  the  right  (d,  d)  extends  no  farther 
than  the  anterior  part  of  the  proventriculus, 
immediately  behind  the  crop  or  honey-bag, 
upon  which  it  is  chiefly  distributed.  The  large 
vesicle  (,/*)  is  connected  with  the  dilated 
trachea?  in  the  succeeding  segments,  and  the 
whole  form  one  continuous  irregularly-shaped 
vesicular  cavity,  which,  along  its  under  surface 
in  each  segment,  is  dilated  into  a  funnel-shaped 
transverse  trachea  (g),  that  anastomoses  with  its 
fellow  of  the  opposite  side,  passing  beneath 
the  muscles  as  in  the  larva.  From  the  upper 
surface  of  the  longitudinal  canals  similar  fun- 
nel-shaped dilatations  (i,  k)  pass  over  the 
dorsal  surface  of  the  abdomen  and  anastomose 
in  like  manner  with  those  of  the  opposite  side, 
besides  which  single  undilated  ramifications  of 
trachea?  (/i)  pass  inwards  on  each  side  and  are 
distributed  over  the  alimentary  canal.  At  the 
posterior  part  of  the  body  the  vesicular  canals 
communicate  directly  by  a  large  branch  (/), 
from  which  large  trunks  are  given  to  the  colon 
and  organs  of  generation.  Thus,  then,  the 
use  of  the  vesicles  is  distinctly  indicated,  even 
in  the  peculiar  distribution  of  undilated  trachea? 
to  the  whole  of  the  organs  of  nutrition.  The 
distribution  of  single  ramified  trachea?  from 
large  vesicles  appears  to  be  constant  in  this 
order ;  it  was  formerly  shown  by  Leon  Du- 
four*  in  Scolia  hortorum,  and  we  have  always 
found  it  in  the  Ichneumonida  and  other  fami- 
lies. Burmeister  states  that  he  has  been  un- 
able to  ascertain  whether  this  is  also  the  case  in 
Diptera,  in  which  order  the  vesicles  are  both 
large  and  numerous.  According  to  Marcel  de 
Serresf  the  Asilida  have  an  immense  number 
of  small  elongated  vesicles  on  each  side.  In 
one  species  they  amount  to  so  many  as  sixty. 
Burmeister  remarks];  that,  in  Lepidoptera,  the 
vesicles  in  the  Sphingida  and  moths  are  chiefly 
found  in  the  males,  which  agrees  with  our  own 
observations  in  Hymenoptera.  In  Acherontia 
Atropos  he  states  also  that  the  existence  of 
spiral  fibre  in  the  vesicles  is  so  distinct  as  not 
to  be  doubted. 

This  is  the  structure  of  the  respiratory 
organs  in  volant  insects,  but  throughout  the 
class,  whether  in  volant  or  creeping  insects, 
there  is  always  a  complete  anastomosis  of  the 
trachea?  on  one  side  of  the  body  with  those  on 
the  opposite,  as  has  been  well  exemplified  by 
almost  all  insect  anatomists,  Swammerdam, 
Lyonet,  Marcel  de  Serres,  Dufour,  Straus,  and 
others. 

The  development  of  the  vesicles  begins  to 
take  place  at  about  the  period  when  the  larva 
ceases  to  feed,  preparatory  to  changing  into  the 
pupa  state.  At  the  time  when  the  larva  of  the 
Sphinx  enters  the  earth,  and  is  forming  the  cell 
in  which  it  is  to  undergo  its  transformation, 
the  longitudinal  trachea?  of  the  second,  third, 
fourth,  and  fifth  segments  become  a  little  en- 
larged. In  the  butterfly,  Vanessa  urtica, 
which  does  not  enter  the  earth,  but  suspends 

*  Journal  dc  Physique,  Sept.  1830. 

t  Meraoires  des  Museum,  torn.  iv.  p.  362. 

X  Op.  cit.  p.  181. 


INSECTA. 


987 


itself  vertically  to  undergo  its  change,  the  di- 
latation commences  while  the  insect  is  spinning 
the  silken  hangings  from  which  it  suspends 
itself;  so  that  the  changes  commence  at  a 
corresponding  period  in  both  insects.  It  is  in 
the  butterfly  that  we  have  most  closely  watched 
the  development  of  the  vesicles.  During  the 
period  that  the  insect  remains  suspended  it 
makes  several  powerful  respiratory  efforts, 
accompanied  by  much  muscular  exertion,  and 
these  efforts  are  continued  at  intervals  until  the 
old  skin  is  fissured  and  thrown  off.  It  is  at 
this  period  that  the  tracheae  become  much  en- 
larged, as  we  have  found  at  about  two  hours 
after  the  insect  has  suspended  itself.  Meckel 
observed  the  sacs  soon  after  the  insect  has 
entered  the  pupa  state,  but  it  will  thus  be  seen 
that  the  expansion  of  the  tracheae  in  the  for- 
mation of  these  sacs  commences  very  much 
earlier.  At  about  half  an  hour  before  the  in- 
sect becomes  a  pupa  we  have  found  the  whole 
of  the  trachea;  more  distended,  particularly 
those  on  the  under  surface  of  the  thorax,  from 
which  branches  are  given  to  the  legs,  so  that 
the  elongation  of  these  trachea;  is  probably 
connected  with  the  subsequent  rapid  develop- 
ment and  extension  of  those  organs.  At  this 
period  the  tracheal  of  the  abdomen  have  ex- 
perienced but  little  alteration.  It  is  at  the 
actual  period  of  transformation  that  all  the 
changes  take  place  most  rapidly.  At  that  time 
the  laborious  respiratory  efforts  made  by  the 
insect  appear  greatly  to  affect  the  condition  of 
all  the  organs.  VVhen  the  skin  is  thrown  off, 
these  efforts  cease  for  a  few  minutes,  after 
which  the  abdominal  segments  become  short- 
ened, and  the  circulatory  fluid  is  propelled 
forwards,  and  the  wings,  then  scarcely  so  large 
as  hemp-seeds,  are  gradually  distended  at  their 
base,  and  at  each  respiration  are  perceptibly 
enlarged,  and  carried  downwards  over  the  under 
surface  of  the  thorax  and  first  abdominal  seg- 
ments. Carus*  attributes  the  development  of 
the  sacs,  and  dilatation  of  the  trachea;,  to  the 
entire  closing  of  the  spiracles,  and  expansion 
of  the  air  contained  within  them,  which  he 
thinks  is  increased  in  quantity  during  the  deve- 
lopment of  the  insect.  But  from  the  circum- 
stance that  all  the  trachea  are  enlarged  imme- 
diately after  the  insect  has  entered  the  pupa 
state,  it  seems  probable  that  this  enlargement 
is  occasioned  simply  by  the  closing  of  the 
spiracles,  and  the  expansion  of  the  air  within 
the  trachea;,  during  the  powerful  respiratory 
efforts,  aided  by  the  receding  of  the  circulatory 
fluid  from  the  abdomen  into  the  partially  de- 
veloped wings,  suddenly  removing  pressure 
from  the  tracheal  tubes,  which  then  become 
distended  by  the  natural  elasticity  of  the  air 
contained  within  them ;  and  further,  that  the 
subsequent  enlargement  of  these  tracheae  into 
distinct  bags  is  occasioned,  not  by  an  in- 
creased quantity  of  air  in  the  vesicles,  as 
Carus  imagines,  but  simply  by  a  continuance 
of  the  same  cause  that  effects  the  first  dila- 

*  Introduction  to  Comparative  Anatomy,  trans- 
lated by  Gore,  1827,  vol.  ii.  p.  167, 


tation  of  the  tracheae,  the  elasticity  of  the 
contained  air,  since  the  dilatation  appears  to 
keep  pace  with  the  gradually  decreasing  size 
of  the  digestive  organs,  and  the  spiracles  are 
not  permanently  closed  during  the  pupa  state, 
respiration  being  continued  at  intervals,  ex- 
cepting perhaps  in  the  most  complete  state  of 
hybernation.  In  accordance  with  this  opinion 
we  find  that,  at  about  half  an  hour  after  the 
change,  the  pro-thoracic  tracheae  that  ramified 
over  the  oesophagus  are  enlarged  to  double 
their  original  diameter,  and  have  begun  to  be 
detached  from  that  organ.  At  seven  hours 
these  changes  have  been  carried  much  farther. 
At  twelve  hours  they  are  still  further  enlarged, 
and  the  principal  alteration  observed  is  the 
diagonal  direction  of  those  from  the  seventh 
spiracles,  which  supply  the  posterior  extremity 
of  the  digestive  stomach,  owing  to  that  organ 
having  now  become  shorter,  previously  to  its 
subsequent  change.  At  eighteen  hours  all  the 
trachea;  of  the  head  and  thorax  are  still  further 
enlarged,  and  those  from  the  third  spiracle  are 
detached  from  the  cardiac  extremity  of  the 
stomach,  and  are  more  enlarged  than  the  others, 
and  those  from  the  ninth  spiracle,  in  the  twelfth 
segment,  which  supply  the  colon,  are  begin- 
ning to  be  distinctly  vesicular.  At  thirty-six 
hours  not  only  have  the  longitudinal  tracheae 
and  their  many  branches  become  dilated,  but 
those  distributed  to  the  different  viscera  have 
also  become  vesicular.  At  forty-eight  hours 
the  development  of  these  parts  is  so  far  ad- 
vanced that  the  whole  have  assumed  the  vesi- 
cular form,  and  those  at  the  anterior  part  of  the 
abdomen  occupy  a  great  proportion  of  that 
region,  and  the  dilatation  of  others  proceeds 
until  within  a  few  days  before  the  perfect  insect 
is  developed,  before  it  is  completed.  The 
only  difference  we  have  observed  between  the 
development  of  these  organs  in  the  Sphinx 
and  the  butterfly  is  in  the  rapidity  with  which 
the  changes  are  effected.  The  Sphinx  re- 
mains many  months  in  the  pupa  state,  during 
a  great  part  of  which  time  the  changes  are 
almost  or  entirely  suspended.  The  butterfly 
remains  but  a  few  days,  and  in  consequence 
all  the  changes  proceed  with  rapidity,  which  is 
either  greater  or  less  in  proportion  to  the  season 
of  the  year  and  temperature  of  the  atmosphere. 

Function  of  respiration. — Having  dwelt  so 
long  upon  the  structure  of  the  parts  concerned 
in  respiration  we  cannot  venture  at  any  length 
upon  the  phenomena  connected  with  the  func- 
tion, which  properly  belong  to  a  distinct  sub- 
ject. (See  Respiration.)  We  would  remark, 
however,  that  the  circumstances  connected 
with  it  are  in  many  respects  particularly  in- 
teresting, while  the  results  are  similar  to  those 
of  the  respiration  in  other  air-breathing  ani- 
mals. Thus  the  acts  of  respiration  consist  of 
alternate  dilatations  and  contractions  of  the  ab- 
dominal segments,  the  air  entering  the  body 
chiefly  at  the  thoracic  spiracles,  and  partly  also 
at  the  abdominal,  during  which  the  dorsal  and 
ventral  arches  of  the  abdomen  are  alternately 
elevated  and  depressed,  like  the  ribs  of  Ver- 
tebrata.    The  number  and  frequency  of  these 


988 


INSECTA. 


respirations  vary,  as  in  Vertebrata,  according 
to  the  degree  of  activity  and  state  of  excite- 
ment of  the  insect.  Thus  when  an  insect  has 
been  subject  to  long-continued  exertion,  the 
acts  of  respiration  are  quick  and  laborious,  as 
every  one  must  have  observed  in  the  larger 
Bombi,  when  alighting  after  a  long-continued 
flight.  The  contractions  and  extensions  of  the 
abdominal  segments  are  then  short  and  quick, 
and  sometimes  so  labored  that  the  whole  ab- 
domen is  shortened  and  extended  like  the 
flanks  and  ribs  of  the  race-horse,  after  a  long 
and  severely  contested  race.  The  number  of 
respirations,  when  the  insect  is  in  a  state  of 
moderate  excitement,  varies  also  in  different 
species  as  well  as  in  the  different  states  of  the 
same  insect,  and  at  different  periods.  Thus  in 
the  green  grasshopper  we  have  noticed  from 
thirty  to  forty  regular  contractions  in  a  minute, 
alternating,  at  irregular  periods,  with  others 
more  long  and  deep  than  the  rest.  When  this 
insect  was  much  excited  the  intervals  between 
the  long  inspirations  were  longer,  and  the  in- 
spirations when  they  occurred  were  more  deep 
and  laborious.  When  an  insect  is  preparing 
itself  for  flight  the  act  of  respiration  resembles 
that  of  birds  under  similar  circumstances. 
At  the  moment  of  elevating  its  elytra  and  ex- 
panding its  wings,  which  are,  indeed,  acts  of 
respiration,  the  anterior  pairs  of  spiracles  are 
opened,  and  the  air  rushing  into  them  is  ex- 
tended over  the  whole  body,  which,  by  the  ex- 
pansion of  the  air-bags,  is  enlarged  in  bulk, 
and  rendered  of  less  specific  gravity,  so  that 
when  the  spiracles  are  closed  at  the  instant  the 
insect  endeavours  to  make  the  first  stroke  with 
and  raise  itself  upon  its  wings,  it  is  enabled  to 
rise  in  the  air,  and  sustain  a  long  and  power- 
ful flight  with  but  little  muscular  exertion. 
In  the  pupa  and  larva  state  respiration  is  per- 
formed more  equally  by  all  the  spiracles,  and 
less  especially  by  the  thoracic  ones. 

The  frequency  of  the  acts  of  respiration 
seem  to  bear  some  relation  to  the  expenditure 
of  muscular  energy  by  the  insect  in  a  state  of 
activity.  All  volant  insects  respire  a  greater 
quantity  of  air  in  a  given  time  than  terrestrial, 
and  both  these  in  their  perfect  than  in  their 
larva  state.  Thus  in  the  common  hive-bee  we 
have  noticed  from  one  hundred  and  ten  to  one 
hundred  and  sixty  contractions  of  the  abdo- 
minal segments  in  a  minute,  while  in  a  less 
active  state,  when  the  insect  was  entirely  un- 
disturbed, the  acts  of  respiration  seldom 
amounted  to  one-half  that  number.  In  an 
exceedingly  wild  and  irritable  little  bee,  An- 
thophora  retusa,  which  dies  exhausted  from  the 
most  violent  excitement  and  exertion,  in  the 
course  of  an  hour  or  two,  after  being  captured 
and  confined  during  summer,  the  acts  of  re- 
spiration are  often  performed  so  rapidly  that,  on 
one  occasion  on  which  we  observed  them,  they 
amounted  to  two  hundred  and  forty  in  a  minute, 
and  of  course  it  was  only  by  the  closest  atten- 
tion that  their  number  could  be  ascertained. 

Next  to  the  pupa  state,  a  state  of  common 
repose  is  that  in  which  insects  respire  with  the 
least  frequency.    When  a  perfect  insect  or  a 


pupa  has  remained  for  some  time  undisturbed, 
its  respiration  becomes  gradually  slower  and 
slower,  until  at  last  it  is  scarcely  perceptible. 
Thus,  in  the  midst  of  winter,  at  a  temperature 
of  the  atmosphere  a  little  below  freezing,  we 
were  unable  to  detect  more  than  the  very 
slightest  trace  of  respiration  during  two  or  three 
days,  and  even  at  the  expiration  of  fourteen 
days  the  quantity  of  carbonic  acid  gas  formed 
was  very  small.  But  when  the  insect  was  re- 
moved into  a  much  warmer  atmosphere  it 
began  again  to  respire  more  freely,  and  the 
quantity  of  carbonic  acid  produced  in  a  given 
time  was  considerably  increased.  In  a  speci- 
men of  Botnbus  terrestris,  which  had  remained 
at  rest  for  about  half  an  hour,  the  respirations 
had  become  deep  and  laboured,  and  were 
continued  regularly  at  about  fifty-eight  per 
minute.  At  the  expiration  of  one  hundred 
and  forty  minutes,  during  which  time  the  in- 
sect remained  in  a  state  of  repose,  the  respi- 
rations were  only  forty-six  per  minute,  and  at 
the  expiration  of  one  bundled  and  eighty  mi- 
nutes they  were  no  longer  perceptible.  This 
same  insect,  when  first  captured,  and  in  a  state 
of  moderate  excitement,  respired  at  the  rate  of 
one  hundred  and  twenty-five  inspirations  per  mi- 
nute. We  have  noticed  the  like  circumstances  in 
a  female  Sphinx  ligustri,  which  after  it  had  been 
excited  for  a  short  time  in  flight  breathed  at  the 
rate  of  forty-two  respirations  per  minute,  while 
after  it  had  remained  at  rest  about  seventy-five 
minutes  respired  at  the  rate  of  only  fifteen  per 
minute.  Hence  the  quantity  of  air  deterio- 
rated by  an  insect  in  a  given  time  depends 
upon  the  state  of  activity  and  condition  of  life 
of  the  individual.  In  accordance  with  the 
frequency,  and  consequently  the  quantity  of 
respiration,  such  are  the  results.  In  accele- 
rated respiration  the  circulation  of  the  fluids 
is  increased,  and  in  those  conditions,  noticed 
in  another  part  of  this  paper,  in  which  the  cir- 
culation is  accelerated,  the  acts  of  respiration 
are  at  the  same  time  more  frequent. 

The  development  of  heat,  which  is  now  found 
to  take  place  in  all  insects  as  in  the  air-breath- 
ing vertebrata,  depends  mainly  upon  the  quan- 
tity and  activity  of  respiration,  and  the  volume 
and  velocity  of  the  circulation.  In  Hymenop- 
tera,  in  which,  as  we  have  seen,  the  capacity  of 
the  respiratory  organs  is  greater  than  in  other 
insects,  and  consequently  the  quantity  of  air 
deteriorated  in  a  given  time  is  also  greater,  the 
quantity  of  heat  evolved  during  the  process  is 
proportionate  to  the  quantity  of  respiration.  In 
the  larva,  in  which,  in  relation  to  its  size,  the 
quantity  and  energy  of  respiration  are  less  than 
in  the  perfect  insect,  the  quantity  of  heat  deve- 
loped is  also  less,  so  that  in  the  larva?  of  Hyme- 
noptera  it  does  not  exceed  from  two  to  four 
degrees  that  of  the  medium  in  which  the  insect 
is  placed  ;  while  in  the  perfect  insect,  in  a  state 
of  little  activity,  the  quantity  of  heat  developed 
is  apparently  at  its  minimum  amount  at  three 
or  four  degrees  above  the  temperature  of  the 
surrounding  medium.  But  when  the  same 
insect  is  in  a  state  of  moderate  activity,  and 
consequently  is  respiring  more  frequently,  it 


INSECTA. 


989 


amounts  to  even  fifteen  or  twenty  degrees.  In 
all  cases  the  amount  of  temperature  depends 
chiefly  upon  the  quantity  of  respiration. 

We  have  seen  that  in  a  state  of  repose  the 
acts  of  respiration  become  less  and  less  frequent, 
and  that  at  last  they  are  scarcely  perceptible. 
In  like  manner  the  amount  of  heat  generated 
is  proportionate  to  the  diminished  number  of 
respirations,  and  continues  to  be  lessened  until 
the  temperature  of  the  insect  has  very  nearly 
sunk  down  to  a  level  with  that  of  the  atmo- 
sphere. There  are  also  other  circumstances 
which  moderate  the  production  of  heat.  When 
the  insect  is  fasting  less  heat  is  generated,  even 
during  a  state  of  activity,  than  when  the  insect 
is  not  deprived  of  its  proper  quantity  of  food. 
The  cause  of  this  deficiency  seems  readily  to  be 
accounted  for  on  the  consideration  that  no  new 
material,  the  product  of  digestion,  is  taken  into 
the  general  circulation,  and  requires  to  be  assi- 
milated with  the  circulatory  fluids,  and,  conse- 
quently, there  is  less  change  in  the  chemical 
condition  of  the  fluids  at  each  respiration,  than 
when  the  animal  is  taking  its  full  amount  of 
food.  Other  circumstances  also  tend  to  regu- 
late the  amount  of  heat.  When  the  insect  is 
respiring  rapidly,  the  power  and  frequency  of 
its  circulation  are  augmented,  and  not  only  is 
there  a  greater  quantity  of  gaseous  expenditure 
from  the  respiratory  organs,  but  there  is  also  a 
greater  amount  of  cutaneous  expenditure,  which 
tends  to  cool  down  the  insect  by  evaporation 
from  the  surface  of  its  body,  and  diminish  the 
amount  of  heat  developed.  This  expenditure 
is  so  enormous,  as  we  have  elsewhere  shown,* 
that  it  is  more  than  equal  to  the  quantity  of 
solid  matter  excreted  from  the  alimentary  canal 
in  a  given  time,  and,  consequently,  is  a  power- 
ful means  of  reducing  the  temperature  of  the 
insect.  One  very  marked  difference  which  ex- 
ists, in  respect  to  the  function  of  respiration  and 
the  evolution  of  heat,  between  these  air-breath- 
ing invertebrate  and  the  vertebrated  animals 
is,  not  in  their  different  powers  of  generating, 
but  of  maintaining  their  temperature.  Insects 
in  their  low  power  of  maintaining  heat  closely 
resemble  the  true  hybernating  animals.  Any 
great  or  sudden  change  of  temperature  in  the 
surrounding  medium  rapidly  reduces  the  tem- 
perature of  the  insect.  It  is  thus  seen  that  a 
reduction  of  temperature  takes  place  not  only 
at  the  period  of  true  hybernation,  which  insects 
undergo  either  in  their  pupa  or  perfect  state, 
but  also  during  vicissitudes  of  the  season,  as 
well  as  during  natural  repose.  On  the  other 
hand,  it  is  remarkable  that  the  evolution  of  heat 
in  insects  takes  place  as  rapidly  as  it  becomes 
reduced.  Its  increase  is  perceptible  by  the 
thermometer  within  a  very  few  moments  after 
the  insect  has  begun  to  respire  more  rapidly. 
The  explanation  of  this  circumstance  must  be 
sought  for  in  the  peculiar  distribution  of  the 
respiratory  organs,  which  are  extended  over  the 
whole  body,  and  aerate  the  blood  in  every  part 
of  it  at  the  same  instant,  the  result  of  which  is 
the  immediate  evolution  of  a  large  amount  of 
heat,  from  the  changes  that  occur  in  the  fluids 

*  Phil.  Trans.  1837,  p.  2. 


in  vessels  that  partake  both  of  the  venous 
and  arterial  character.  Consequently  a  large 
amount  of  heat  is  liberated  instantaneously, 
whether  the  oxygen  of  the  atmosphere  be  ab- 
sorbed into  the  circulatory  system,  or  whether 
the  whole  of  the  changes  take  place,  and  car- 
bonic acid  be  formed  in  the  respiratory  struc- 
tures. The  same  rapidity  with  which  the  heat 
is  evolved  from  the  body  accompanies  its  dimir 
nution  when  the  quantity  of  air  inspired  is 
lessened.  In  confirmation  of  this  view  with 
regard  to  the  production  of  heat  being  the  result 
of  the  chemical  changes  in  the  air  inspired, 
there  is  one  remarkable  circumstance  that  can- 
not be  passed  over.  It  is  the  voluntary  power 
which  we  have  found  is  possessed  by  some 
species  of  generating  heat  by  means  of  accelera- 
ting their  respiration.  We  observed  this  fact  in 
the  individuals  of  a  nest  of  Humble-bees,  Bom- 
bus  terrestris,  which  were  confined  by  us  for 
the  purpose  of  watching  their  habits.  Huber 
formerly  noticed  that  bees  are  in  the  habit  of 
incubating  on  the  cells  of  their  pupa;,  before  the 
perfect  insects  are  developed,  and  we  have  had 
ample  opportunities  of  confirming  his  observa- 
tions. It  was  during  the  time  that  we  were 
engaged  in  watching  these  habits  that  we  dis- 
covered that  bees  possess  this  voluntary  power 
of  increasing  their  temperature.  The  manner 
in  which  the  bee  performs  her  incubatory  office 
is  by  placing  herself  upon  the  cell  of  a  nymph 
that  is  soon  to  be  developed,  and  then  begin- 
ning to  respire  at  first  very  gradually.  In  a 
short  time  the  respirations  become  more  and 
more  frequent,  until  at  length  they  are  increased 
to  one  hundred  and  twenty  or  one  hundred 
and  thirty  per  minute.  The  body  of  the  insect 
soon  becomes  of  a  high  temperature,  and  on 
close  inspection  is  often  found  to  be  bathed 
with  perspiration.  When  this  is  the  case  the 
temperature  of  the  insect  soon  becomes  re- 
duced, and  the  insect  leaves  the  cell,  and  ano- 
ther bee  almost  immediately  takes  her  place. 
When  respiration  is  performed  less  violently, 
and  consequently  less  heat  is  evolved,  the  same 
bee  will  often  continue  on  a  cell  for  many  hours 
in  succession.  During  these  observations  we 
have,  in  some  instances,  found  the  temperature 
of  a  single  bee  exceed  that  of  the  atmosphere 
more  than  twenty  degrees.  Thus  when  the 
temperature  of  the  atmosphere  was  73°  5  Fahr. 
that  of  four  female  bees,  in  the  act  of  incuba- 
tion, was  94°  1.  On  another  occasion  when 
the  atmosphere  was  72°  5,  a  single  bee, 
nursing  on  a  single  cell,  from  which  a  per- 
fect insect  was  developed  about  eight  hours 
afterwards,  afforded  a  temperature  of  92°  3, 
the  bulb  of  the  thermometer  being  placed 
between  the  abdomen  of  the  bee  and  the 
cell.  The  insect  was  then  breathing  at  the 
rate  of  one  hundred  and  twenty  respirations  per 
minute.  In  another  instance,  the  temperature 
of  the  atmosphere  being  the  same,  that  of  ano- 
ther bee  in  the  act  of  nursing  was  94°  5. 
This  extreme  amount  of  heat  was  evolved  en- 
tirely by  an  act  of  the  will  in  accelerating  the 
respiratory  efforts,  a  strong  indication  of  the  re- 
lation which  subsists  between  the  function  of 
respiration  and   the  development  of  animal 


990 


INSECTA. 


heat.  These  curious  facts  tend  much  to  con- 
firm the  opinion  as  to  the  chief  origin  of  animal 
heat,  but  for  farther  illustration  of  this  interest- 
ing subject  we  must  refer  our  readers  to  the 
article  Respiration. 

Organs  of  generation. — These  parts  have 
already  been  treated  of  to  some  extent  in  a 
preceding  article,  (Generation,  Organs  of,) 
and  the  forms  which  they  assume  in  different 
orders,  more  particularly  those  of  the  male 
organs,  having  in  part  been  described,  we 
shall  only  briefly  allude  to  them  on  the  present 
occasion,  in  consequence  partly  of  the  great 
length  to  which  this  paper  has  already  been  ex- 
tended, and  partly  that  we  shall  necessarily 
return  to  this  subject,  more  especially  with  re- 
ference to  the  functions  of  these  parts,  in  de- 
scribing that  class  of  Articulata,  which  in  every 
respect  are  so  closely  related  to  insects,  the 
Myriapoda,  to  which  we  must  refer. 

In  our  observations  on  the  skeleton  we  have 
shown  that  the  terminal  segments  of  the  body 
invariably  form  part  of  the  external  organs  of 
generation.  The  long  ovipositor  of  the  Chry- 
sidida,  composed  of  four  distinct  annuli,  retrac- 
tile within  one  another,  and  even  within  the 
proper  abdomen  itself,  are  only  the  terminal 
segments  of  the  body,  which  is  thus  made  to 
consist  of  fewer,  but  proportionately  larger 
annuli  than  the  abdomen  of  those  in  which  so 
many  segments  are  not  employed  in  the  forma- 
tion of  the  generative  organs.  A  corresponding 
structure  is  also  seen  in  the  Panorpidce,  in 
which  the  separate  annuli,  not  retractile  to  so 
great  an  extent  as  in  the  Chrysididce,  but  capa- 
ble of  being  extended  to  as  great  a  length,  are 
distinctly  shown  to  form  part  of  the  abdomen, 
while  the  corresponding  parts  in  the  male,  the 
terminal  segments,  are  developed  into  a  claw- 
shaped  prehensile  organ.  A  similar  modifica- 
tion of  structure  exists  in  all  other  insects.  In 
some  species  one  or  more  of  these  parts  be- 
comes atrophied,  or  is  developed  to  a  greater 
extent  than  the  others,  and  the  result  is  that  in 
some  instances  we  find  long,  exsertile,  and  appa- 
rently new  organs,  while  in  others  some  parts, 
even  of  the  annuli  themselves,  appear  to  be  ab- 
sent. But  the  normal  number  is  almost  every 
where  present,  either  simply  as  terminal  plates 
of  the  abdomen,  between  which  the  proper  ex- 
cretory portion  of  the  organs  of  generation  is 
concealed,  or  more  highly  developed,  and  form- 
ing a  separate  sheath  for  that  structure. 

In  the  male  insect  (fig.  437)  the  organs  con- 
sist of  an  external  portion,  the  penis  (h),  or 
"  organ  of  intromission,"  in  which  is  inclosed 
the  termination  of  the  ductus  ejaculatorius, 
which  extends  backwards,  and  is  connected 
with  the  vesicular  seminales  (e)  and  vasa  dej'e- 
rentia,  which  are  connected  with  the  epididymis 
and  the  proper  testes  («).  These  parts  are 
found  in  a  large  number  of  insects,  in  some  de- 
veloped to  a  great  extent,  but  in  others  almost 
entirely  atrophied.  This  is  the  order  in  which 
the  parts  are  met  with  when  passing  from 
without  inwards. 

The  penis  of  the  male,  like  the  ovipositor  of  the 
female,  assumes  a  variety  of  forms.  It  is  usu- 
ally inclosed  between  two  lateral  plates,  the  ana- 


Male  organs  of  generation 
of  Athalia  centifoliee. 
m  ( Prize  Essay.)  j 


Fig.  437.  logues  of  the  sheath 

of  the  ovipositor,  and 
which  are  derived 
from  the  terminal  or 
penultimate  segment 
of  the  body.  With- 
in this  isacorrugated 
soft  membrane,  the 
preputium,  which  is 
continuous  with,  and 
is  reflected  inwards 
from  the  inferior 
margin  of  the  anal 
aperture,  and  sepa- 
rates the  organs  of 
generation  from  the 
alimentary  canal. 
When  the  penis  is 
retracted  it  is  covered 
by  this  membrane, 
which  is  corrugated 
upon  it  (fig.  402,  s). 
In  Coleoptera,  as  in 
the  Carabidie  and 
Melolonthida,  the 
penis  is  a  long  hor- 
ny tube,  retractile 
within  the  abdomen  on  the  under  surface  as  far 
as  the  anterior  segments.  The  strong  horny  co- 
vering of  this  organ  is  simply  a  consolidated  state 
of  parts  of  the  tissues  which  in  other  instances 
are  soft  and  flexible.  It  contains  within  it  the 
excretory  portion  of  the  ejaculatory  duct.  In 
most  of  the  Coleoptera,  and  in  many  other 
species,  it  has  this  strong  hardened  exterior,  ne- 
cessary apparently  for  its  employment  by  cer- 
tain species,  in  which  there  is  little  flexibility 
of  the  abdominal  segments,  as  an  organ  of  in- 
tromission. In  Carabus  monilis,  as  noticed 
also  in  C.  clathratus  by  Burmeister,  the  hard- 
ened case  of  the  penis  is  gently  curved  down- 
wards to  facilitate  its  introduction  into  the  vulva 
of  the  female.  At  its  extremity  on  the  under 
surface  it  is  a  little  elongated,  and  it  is  termi- 
nated by  a  soft  corrugated  glandiform  structure, 
which  is  perforated  in  its  centre,  and  represents 
a  glans  penis,  the  perforation  in  its  centre  being 
the  oritice  of  the  excretory  duct.  In  other 
Coleoptera  the  penis  is  also  inclosed  in  a  horny 
sheath,  and  presents  a  great  variety  of  forms  in 
different  species.  In  many  instances  it  is  fur- 
nished at  its  extremity  with  short  hooked  spines, 
by  means  of  which  the  male  effectually  retains 
his  connexion  with  the  female.  The  external 
sheath  of  the  male  organs,  which  incloses  the 
penis,  is  analogous  to  that  of  the  ovipositor  of 
the  female,  and  is  employed  when  it  is  well 
developed  to  open  the  vulva  of  the  female.  In 
many  species  it  is  scarcely  at  all  developed, 
being  like  the  sheath  of  the  ovipositor  only  a 
highly  developed  portion  of  the  lateral  plates  of 
the  terminal  abdominal  segments.  The  cir- 
cumstances above  referred  to  will  not  allow  us 
to  describe  in  detail  the  forms  of  these  organs 
of  generation  in  many  species,  we  shall  there- 
fore content  ourselves  with  a  brief  notice  of 
some  of  those  of  the  Hymenoptera  (fig.  437). 
The  general  form  of  the  penis  in  this  Order  is 
similar  to  that  of  Athalia,  and  consists  of  a 


INSECTA. 


991 


short  valvular  projectile  organ,  covered  exter- 
nally by  two  pointed  horny  plates  (i),  clothed 
with  soft  hairs.  Above  these  are  two  other 
irregular  double-jointed  plates  (/),  convex  on 
their  outer  and  concave  on  their  inner  surface, 
and  surrounded  at  their  base  by  a  bony  ring 
(/c).  They  are  half  corneous  half  membranous, 
and  folded  together  like  a  closed  fan,  and  are 
furnished  at  their  posterior  margin  with  horny 
hooks  (t),  which  are  used  as  organs  of  prehen- 
sion. Between  these  in  the  middle  line  are 
two  elongated  muscular  parts  (?n),  which  when 
applied  together  form  a  pointed  structure,  and 
inclose  between  them  in  its  retracted  state  the 
proper  intromittent  organ  (h).  These  perhaps 
assist  to  dilate  the  vulva  of  the  female,  like  the 
plates  above  noticed  in  the  Coleoptera.  In 
many  instances,  as  in  Anthidium  munkatum, 
the  posterior  margin  of  the  last  true  abdominal 
segment  is  armed  with  spines  that  are  curved 
downwards,  and  serve  to  retain  the  female,  and 
this  is  also  the  case  in  the  Chrusidida.  In 
Anthophora  retusa  the  horny  penis  formed  of 
the  last  two  segments  of  the  larva  has  also  two 
external  plates  developed  into  hooked  prehen- 
sile organs,  with  which  the  insect  grasps  the 
abdomen  of  the  female  at  the  moment  of  actual 
connexion.  In  the  Sphinx  (fig.'iQV)  and  other 
Lepidoptera  the  appendages  of  the  anal  seg- 
ment appear  to  be  analogous  to  the  sheath  of 
the  ovipositor  in  the  preceding  orders.  On 
each  side  of  these  parts  at  their  inner  surface 
are  two  horny  plates,  which  form  the  lateral 
boundary  of  the  male  organs.  Within  these  is 
a  cloaca,  in  which  the  anal  aperture  terminates, 
and  immediately  beneath  it  are  situated  the 
male  organs.  These  consist  of  an  extensile 
bifid,  ejaculatory  organ  included  between  two 
soft  valvular  parts.  They  form  the  virile 
organ.  In  the  Sphinx  the  posterior  margin  of 
the  dorsal  plate  of  the  terminal  segment  is 
armed  with  a  slender  curved  hook,  bifid  at  its 
apex,  and  bent  downwards,  like  the  hooks  in 
the  body  of  Hymenoptera,  for  retaining  con- 
nexion with  the  female.  Among  the  Diptera 
the  Asilida  have  the  male  organ  formed  in  a 
somewhat  similar  manner.  The  terminal  seg- 
ment of  the  body  forms  a  pair  of  broad  horny 
plates,  which  inclose  between  them  the  double 
stiliform  excretory  canal. 

The  ductus  ejaculatorius  passes  backwards 
from  the  penis  as  a  single  canal,  which  either  is 
exceedingly  short,  as  in  Athalia,  (Jig.  437,/), 
or  is  a  very  long  tube,  forming  many  convolutions 
in  its  course,  as  in  many  of  the  Coleoptera. 
Into  this  canal  open  the  vesicula  seminules  and 
the  vasa  deferentia.  The  vesicula  seminules  are 
usually  long  convoluted  ccecal  tubes,  which 
assume  a  variety  of  forms,  sometimes  branched 
sometimes  simple.  They  are  two,  and  some- 
times four  in  number.  In  some  species,  as  in 
Athalia  (e),  they  are  exceedingly  short,  and 
very  much  dilated,  serving  evidently  as  recep- 
tacles for  the  semen  as  it  is  secreted  by  the 
testes,  and  conveyed  towards  the  ejaculatory 
duct  by  the  vasa  deferentia  (d).  These,  like 
the  seminal  vessels,  vary  in  number  according 
to  the  number  of  the  testes.  When  the  whole 
of  the  testes  are  aggregated  together,  the  vasa 


deferentia  that  proceed  from  them  are  united 
from  each  set  of  testes  into  a  single  tube  on 
each  side  (b),  but  when  the  testes  remain  dis- 
tinct from  each  other,  each  deferential  vessel 
passes  at  first  separately  from  each  testis  for  a 
short  distance,  and  the  whole  are  then  collected 
together,  and  form  on  each  side  a  single  tube, 
which,  after  many  convolutions,  either  is  in- 
serted into  the  extremity  of  the  seminal  vessel, 
or  is  inserted  along  with  it  into  the  commence- 
ment of  the  ejaculatory  duct.  The  length  of 
the  common  deferential  vessels  is  sometimes  so 
great,  and  they  are  so  much  convoluted,  as  to 
be  readily  mistaken  for  testes,  much  larger  than 
the  proper  testicles.  This  is  the  case  in  Athalia 
(d).  The  proper  testes  are  usually  several 
rounded  glandular  bodies,  in  some  instances,  as 
in  Melotontha*  and  Lucanus,  amounting  to  as 
many  as  six  on  each  side,  and  in  a  few  in- 
stances, as  in  Athalia,  even  to  as  many  as  thir- 
teen. In  form  they  are  sometimes  rounded,  and 
sometimes  are  elongated  coeciform  tubes.  They 
are  usually  regarded  as  ccecal  organs,  but  in 
some  instances  we  have  distinctly  traced  minute 
vessels  connected  with  them,  but  whether  these 
vessels  passed  by  open  mouths  directly  into  the 
coeca,  or  whether  distributed  over  their  surface, 
is  perhaps  still  a  question;  our  impression  cer- 
tainly is  that  they  enter  the  testes.  Besides 
these  parts,  there  are  in  some  instances  struc- 
tures that  resemble  an  epididymis,  as  in  Hy- 
drous,\  but  these  are  generally  absent. 

These  organs  lie  within  the  abdominal  cavity, 
in  general  on  each  side  of  the  alimentary  canal, 
and  sometimes  above  it,  as  in  the  instance  of 
the  Lepidoptera,  in  which  the  two  separate 
testes  of  the  larva  (jig.  364,  i)  are  united  in 
the  perfect  insect  into  one  mass,  which  is  situ- 
ated immediately  beneath  the  dorsal  vessel 
(fig.  366,  i).  In  each  of  these  cases  the  con- 
nexion with  the  vessel,  as  formerly  noticed,  is 
distinctly  traced.  Besides  these  parts  we  ought 
also  to  notice  some  which  are  appendages  of 
the  organs  similar  to  appendages  found  in  the 
female,  but  the  function  of  which  is  not  dis- 
tinctly understood. 

In  the  female  the  organs  of  generation  are 
more  simple  than  in  the  male.  Of  these  we 
have  first  to  notice  those  external  parts  which 
form,  as  we  have  stated,  either  the  long  ex- 
tended ovipositor  of  the  Gryllida:,  the  sheath 
of  the  sting  of  the  bee  (jig.  438,  A,  a,d),  or 
the  sheath  or  valves  of  the  ovipositor  of  the 
Terebrantia  (C,  b).  The  condensed  descrip- 
tion of  these  parts  that  has  been  given  by  Mr. 
WestwoodJ  clearly  explains  their  structure. 
He  remarks  that,  "  from  the  centre  of  the 
under  side  of  the  abdomen,  near  its  extre- 
mity, arise  two  plates,  each  consisting  of 
two  joints,  sometimes  valvular  and  together 
forming  a  scabbard,  sometimes  more  slender, 
and  resembling  palpi,  and  sometimes  very 
long ;  between  these  plates,  as  they  exist  in  the 
bee  (A,  b),  under  the  form  of  two  flattened 
plates,  with  a  pair  of  terminal  lobes,  arise  two 
other  pieces  which  are  very  slender,  serrated 

*  Straus, 
t  Dufour. 

t  Entomologist's  Text  Book,  p.  375. 


992 


INSECTA. 


Fig.  438. 


ft 


A,  lateral  view  of  the  sting  of  the  Bee.  (  Westwood. ) 

a,  the  sheath;  b,  terminal  segment  of  the  abdo- 
men ;  c,  the  barbs  or  proper  sting  ;  d,  the  chan- 
neled surface  of  the  sheath  of  the  sting  in  which 
the  barbs  are  concealed. 

B,  the  poison-bag  and  vessels  of  the  sting  of  the 
Anthophora  retusa  ^Newport)  ;  a.  sheath  of  the 
sting  ;  6,  the  dilated  extremity  of  the  poison  duct ; 
c,  d,  the  bag  ;  e,  efferential  vessel ;  f,  the  secretory 
organs;  g,  their  vessels. 

C,  terminal  segment  of  the  abdomen  of  a  saw-fly, 
Triclwsoma  (Lyonet)  ;  a,  dorsal  end  of  the  ter- 
minal segment ;  b,  sheath  of  ovipositor  or  terminal 
ventral  arch  ;  c,  d,  the  inner  plates  or  saws,  analo- 
gous to  the  barbs,  c,  of  the  sting  of  the  bee. 

D,  one  of  the  double  lancet-pointed  saws  of 
Athalia  centifolice. 

at  the  tip  in  the  bees  (c)  but  much  broader  in 
the  saw-flies  (C,  c,  d)  and  transversely  striated, 
forming  the  saws  with  which  these  insects  are 
provided :  moreover  these  two  pieces  are  re- 
ceived in  the  bees  into  a  canal  (A,  d),  but  in 
the  saw-flies  this  gutter  is  broad,  flattened,  and 
divided  into  two  separated  parts,  forming  the 
backs  of  the  two  saws.  In  the  Ichneumons 
these  various  parts  are  so  slender  that  at  the 
first  sight  they  appear  to  consist  but  of  a  single 
piece :  on  more  minutely  examining  the  in- 
strument, however,  it  will  be  found  that  it 
consists  of  a  scabbard,  composed  of  two  pieces, 
inclosing  a  fine  hair-like  bristle,  which  is,  in 
fact,  the  exact  analogue  of  the  stinging  part  of 
the  bee's  sting,  consisting  of  three  pieces." 
This  organ  constitutes  both  a  means  of  defence 
and  also  of  depositing  the  eggs.  There  have  been 
some  doubts  with  regard  to  this  fact  in  the 
bees,  some  having  questioned  whether  the  sting 
is  at  all  employed  in  oviposition  by  these  in- 
sects ;  but  a  most  careful  and  accurate  ob- 
server, Dr.  Bevan,  distinctly  states  that  the 
ova  pass  along  the  sting  of  the  bee  lo  be  de- 
posited, and  this  statement  is  confirmed  by 
the  fact  that  this  is  certainly  the  case  in  the 


analogous  instrument  of  the  saw-flies,  as  we  our- 
selves have  distinctly  witnessed  in  Athalia 
ce.ntifoliaz.  The  analogy,  therefore,  of  the  sting 
with  the  ovipositor  of  the  Gryllidaz,  of  the  saw- 
flies,  and  other  insects,  is  distinctly  proved.  In 
Athalia  the  ovipositor  is  a  very  interesting 
organ.  It  occupies  the  under  surface  of  the 
seventh  and  eighth  segment  of  the  body,  and 
is  approximated  to  the  posterior  margin  of  the 
sixth,  a  part  of  the  seventh  having  been  re- 
moved. Four  tendons  for  the  insertion  of 
muscles  originate  from  the  extremity  of  the 
two  halves  of  the  ovipositor.  In  the  mem- 
brane that  unites  on  the  under  surface  the  two 
halves  of  the  ovipositor,  is  situated  the  vaginal 
orifice  between  the  two  saw-shaped  organs 
(C,  c,  d,  D).  Each  of  these  parts  is  composed 
of  two  plates  applied  together  back  to  back, 
and  which  together  form  a  pointed  instrument 
resembling  a  lancet  (D).  The  upper  one  of 
these  plates  (i)  is  furnished  with  small  sharp- 
pointed  teeth  directed  backwards,  and  the 
under  one  (/c)  with  fourteen  long  and  slightly 
convex  ones.  With  the  point  of  this  instru- 
ment the  insect  pierces  the  edges  of  the  leaves 
of  the  turnip,  separating  the  cuticle  with  its 
saw  preparatory  to  depositing  its  egg,  which  is 
conveyed  along  its  inner  surface,  which  is 
slightly  concave  to  allow  of  its  safe  transit 
along  the  plates.  Posteriorly  and  external  to 
these  plates  are  the  two  sheaths  of  the  ovipo- 
sitor (C,  b)  analogous  to  one  portion  of  the 
ovipositor  of  the  Gryllidce.  In  all  those  Hy- 
menoptera  furnished  with  an  ovipositor  there  is 
also  an  apparatus  for  secreting  a  peculiar  fluid, 
and  this  apparatus  is  believed  to  be  analogous 
to  the  appendages  of  the  male  organs  above 
alluded  to,  the  use  of  which  is  not  well  under- 
stood. In  the  female  these  parts  consist  of  an 
excretory  duct,  and  bag,  or  receptacle  for  the 
fluid,  a  convoluted  efferential  vessel, and  proper 
secretory  organs.  In  the  wild  bee,  Anthophora 
retusa  (B),  at  the  base  of  the  sheath  (a)  in 
which  the  two  barbs  of  the  sting  (A,  e)  are 
concealed,  is  a  smooth  dilated  space,  into  which 
the  poison  is  first  received  at  the  base  of  the 
sting.  The  poison  is  conveyed  to  this  space 
by  the  efferential  duct  (c)  from  an  oval  sac  (d ), 
in  which  it  is  accumulated  as  secreted,  and  into 
which  it  is  poured  by  a  very  large  and  much 
convoluted  efferential  vessel  (e),  which  receives 
the  fluid  from  two  coeciform  glandular  organs 
(f),  which  unite  as  they  enter  the  efferential 
vessel.  These  secretory  organs  receive  at  their 
apparently  closed  extremity  each  a  minute 
vessel,  which  we  have  distinctly  traced  to  some 
distance  from  them,  but  not  to  its  termination. 
When  the  poison  is  ejected  from  the  bag  (d ) 
into  the  base  of  the  sting,  it  passes  along  be- 
tween the  two  barbs,  as  in  a  little  gutter,  into 
the  wound.  Swammerdam  delineated  these 
parts  in  the  honey-bee,  but  did  not  notice  the 
vessels  proceeding  from  the  secretory  organs. 
In  another  insect  of  the  same  class  there  are 
similar  structures.  Thus,  in  Athalia  (Jig. 439), 
the  bag  (g)  is  oval,  but  the  efferential  vessel  is 
entirely  absent,  the  fluid  being  poured  directly 
from  the  secretory  vessels  (/()  into  the  bag  with- 
out passing  along  any  other  tube.  The  vessel  is 


INSECTA. 


993 


Fig.  439. 


Female  organs  of  generation  of  Athalia  centifoliae. 
(  Prize  Essay.) 

also  absent  between  the  bag  and  the  base  of  the 
ovipositor,  so  that  the  fluid  is  forced  directly 
from  the  bag  at  the  moment  it  is  employed. 
There  is  a  somewhat  similar  structure  in  the 
Hornet,  although  the  vessel  between  the  bag 
and  sting  is  present  as  in  the  bee.  Burmeister 
has  suggested  that  the  poison-gland  may  per- 
haps be  an  urinary  organ,  but  the  circum- 
stance of  the  fluid  contained  in  it  being  em- 
ployed by  the  insect  to  inject  into  the  cavity 
iji  which  it  deposits  its  ova,  seems  opposed  to 
this  opinion,  although  that  of  its  being  em- 
ployed by  the  bee  as  a  means  of  defence  may 
be  favourable  to  it.  The  nature  of  this  fluid 
is  distinctly  acid,  as  remarked  by  Dr.  Bevan 
in  the  honey-bee,  and  as  found  by  ourselves  in 
several  instances.  The  vaginal  aperture  at  the 
base  of  the  ovipositor  forms  the  external  orifice 
of  the  common  oviduct  or  proper  laying  tube 
(e).  This  in  some  instances  is  simply  a  di- 
lated orifice,  the  internal  lining  of  which  is 
.continuous  with  that  of  the  internal  part  of  the 
ovipositor.  This  common  oviduct  is  either  a 
simple,  straight,  uniform  tube,  or  in  some  in- 
stances is  a  little  dilated  laterally  into  pouches, 
in  which  are  received  the  lateral  appendages  of 
the  male  organ,  as  in  Melolontha.  At  its 
termination  the  common  oviduct  divides  into 
or  rather  receives  two  separate  tubes  (d ), 
one  from  each  side,  analogous  to  the  eft'erential 
vessels  of  the  male  organs.  On  the  upper 
surface  of  the  common  oviduct,  there  are 
appendages  that  vary  in  number  from  one  to 
five.  The  chief  of  these,  the  spermatheca  (f), 
alone  exists  in  Athalia.  It  is  into  this  sac  that 
the  fluid  of  the  male  is  ejected  during  co- 
pulation. Audouin  states  that  the  male  organ 
is  projected  into  it.  We  have  invariably  found 
this  vesicle,  which  is  exceedingly  large  in  Meloe, 
filled  with  white,  opaque,  seminal  fluid  after 
connexion  with  the  male,  previously  to  which 
time  we  have  as  invariably  found  this  vesicle 
^mpty.    This  appendage  is  simple  in  many  ,of 

VOh,  II. 


the  Orthoptera  as  well  as  in  Hymenoptera,  but 
in  some  other  species  there  are  also  additional 
vesicular  appendages  which  have  been  de- 
scribed as  secreting  a  glutinous  fluid.  In  all  in- 
stances these  are  attached  to  and  pour  their  con- 
tents into  the  common  oviduct,  through  which 
the  eggs  pass  to  be  deposited.  In  the  middle 
line,  at  the  union  of  the  oviducts,  are  situated 
the  terminal  ganglia  of  the  nervous  cord 
(10,  11),  when  the  cord  is  extended  to  the 
posterior  part  of  the  abdomen.  But  when  this 
is  not  the  case,  and  the  nerves  simply  radiate 
from  the  thorax  into  the  abdomen,  the  terminal 
pair  of  nerves  still  pass  in  a  corresponding 
direction  over  the  union  of  the  oviducts,  thus 
always  occupying  a  position  between  the  organs 
of  generation  and  the  termination  of  the  ali- 
mentary canal.  From  the  two  oviducts  origi- 
nate the  proper  ovarial  tubes.  In  Athalia  cen- 
tifolia  there  are  eighteen  (a,  b,  c)  attached  to 
each  oviduct,  but  in  some  other  instances,  as 
in  Mel'ue,  in  which  the  upper  part  of  the 
oviduct  on  each  side  is  dilated  into  an  im- 
mense bag  resembling  an  uterus,  they  amount 
to  some  hundreds  of  exceedingly  short  tubes 
containing  each  but  one  or  two  ova.  In  Melo- 
lontha and  Lucanus  there  are  six  on  each  side, 
but  in  some  instances,  as  in  Lixus,  as  shewn 
by  Dufour,*  there  are  only  two  on  each  side. 
These  ovarial  tubes  gradually  decrease  in  size 
from  their  base  to  their  apex,  and  those  from 
each  side  are  collected  together  at  their  apices, 
and  are  said  to  terminate  each  in  a  dilated 
ccEcal  extremity,  but  we  must  confess  we  have 
never  yet  traced  this  structure  in  any  instance. 
Muller,  as  above  stated,  traced  a  connexion 
between  the  extremities  and  the  ovarial  tubes 
and  the  dorsal  vessel  in  Phusma,  and  many 
other  insects,  as  we  have  also  done  in  several 
instances,  but  the  nature  of  these  connexions 
is  disputed.  They  certainly  appeared  to  us 
to  be  vascular,  as  supposed  by  Muller,  and 
we  have  already  stated  the  reasons  that  led  us 
to  the  same  opinion. 

We  shall  enter  on  a  consideration  of  the 
function  of  the  organs  of  generation  when  con- 
sidering this  subject  in  Myriapoda. 

In  concluding  this  lengthened  article  we 
have  only  further  to  remark  that  the  tegumen- 
tary  appendages  consist  of  hair,  scales,  and 
spines.  The  first  of  these  serves  as  a  covering 
for  the  bodies  of  many  species,  more  particu- 
larly the  Hymenoptera,  and  is  also  found 
under  the  limbs  in  many  Coleoptera.  The 
scales  are  peculiar  appendages  and  may  be 
considered,  according  to  many,  as  simply  flat- 
tened hairs.  They  entirely  cover  the  bodies  of 
many  species,  as  for  instance  the  Lepidoptera. 
The  curious  forms  and  marking  of  these  parts 
are  sometimes  exceedingly  beautiful ;  but  the 
limits  of  our  article  will  not  allow  of  our  en- 
tering at  present  on  the  consideration  of  them. 
The  spines  are  found  much  on  the  wing  of  Hy- 
menoptera and  are  often  mistaken  for  true  hairs, 
between  which  and  spines,  and  also  between 
«  these  and  scales,  there  is  a  difference  of  origin, 

*  Annales  des  Sciences  Naturelles,  torn.  vi. 
pi.  20. 

3  T 


994 


INSECTIVORA. 


spines  being  usually  developed  directly  from  a 
trachea  or  part  of  a  membrane  in  the  immediate 
vicinity  of  a  trachea. 

Bibliography.— In  addition  to  the  foot-notes 
attached  to  the  article  the  following  are  some  of  the 
principal  works  on  Insects  :  De  Animalibus  Insectis 
libri  septem,  A  uctore  Vlysse  Aldrovandee,  fol.  Bonon. 
1602.  Experimenta  circa  Generationem  Insecto- 
rum,  Francisco  Redi,  Florence,  1668.  De  Bombyce, 
M.  Malpighi,  1687?  Historia  Insectorum,  Londini, 
1710.  Methodus  Insectorum,  seu  Insecta  in  Metho- 
dum  aliqualem  digesta,  Johannes  Ray.  Systema 
Naturae,  1735-1770,  Carolus  von  Linnceus.  Memoires 
pour  servir  a  l'Histoire  des  Insectes,  par  Charles  De 
Geer,  7  torn.  4to.  Stockholme,  1752.  Traite  d'ln- 
sectologie,  par  Charles  Bonnet,  8vo.  Paris,  1748. 
Biblia  Natura;,  fol.  by  J.  Swammerdam,  translated 
by  Thomas  Flloyd,  with  Notes  by  J.  Hill,  London, 
1758.  Entomologia  Carniolica,  exhibens  Insecta 
Carniolia?  indigene,  &c.  8vo.  Joannis  Antonii  Scopoli. 
Vindobona;,  1763.  Memoires  pour  servir  a  l'Histoire 
des  Insectes,  6  torn.  4to.  par  Rene  Antoine  Erchhault 
de  Reaumur.  Traite  Anatom.  de  la  Chenille,  4to. 
par  Pierre  Lyonet,  1760.  Spicilegia  Zoologica,  &c. 
a  Petr.  Sim.  Pallas,  M.D.  4to.  Berlin,  1767-1780. 
Systema  Entomologia;,  &c.  8vo.  Jo.  Christ.  Fabricii, 
Flensburgi  et  Lipsiae,  1775.  Nova;  species  Insec- 
torum Centuris  1.  Auctore  Joanne  Rionoldo  Fostero, 
8vo.  Londini,  1771.  Historia  Naturalis  Curculio- 
num  Suecize,  Auctore  Gabriel  Bonsdorf,  4to.  Up- 
Bali;e,  1785.  Entomologia  Parisiensis,  edente.A.  F. 
Fourcroy,  M.D.  2  torn.  12mo.  Parisiis,  1785.  Ex- 
position of  English  Insects,  arranged  according  to 
the  Linnean  System,  4to.  London,  by  John  Harris, 
1782.  Entomologia  Helvetique  ou  Catalogue  des 
Insectes  de  la  Suisse,  ranges  d'apres  une  nouvelle 
Methode,  avec  Descriptions  et  Figures,  Claiville, 
Zurich,  1798.  Tableau  elementaire  de  l'Histoire 
Naturelle  des  Animaux,  par  G.  Cuvier,  1797. 
Natural  History  of  British  Insects,  by  E.  Donovan, 
16  vol.  8vo.  London.  1792-1818.  De  antennis  In- 
sectorum, 8vo.  1799,  Lehmann.  Vivarium  Naturae, 
the  Naturalist  Miscellany,  by  G.  Shaw.  Lepidop- 
tera  Britannia;,  Auctore  A.  H.  Haworth,  8vo.  Lon- 
dini, 1803.  Monographia  apum  Anglia:,  by  W. 
Kirhy,  M.A.  2  vol.  8vo.  Ipswich,  1802.  Introduc- 
tion to  Entomology,  by  William  Kirby,  M.A.  and 
William  Spence,  vol.  iv.  1816-1828.  Historia  Nat. 
des  Animaux  sans  Vertebres,  &c.  par  M.  le  Cheva- 
lier de  Lamarck,  5  torn.  8vo.  Paris.  Extrait  du 
Cours  de  Zoologie,  &c.  par  M.  de  Lamarck,  1812, 
8vo.  Elements  of  Natural  History,  2  vol.  8vo. 
Iiondon  and  Edinburgh,  1802,  by  Stewart.  Histoire 
Naturelle  des  Crustaces  et  des  Insectes,  par  P.  A. 
Latreille.  British  Entomology,  by  John  Curtis, 
F.L.S.  Histoire  abregee  des  Insectes,  Paris, 
1764,  2  torn.  4to.  by  Geoffroy.  Illustrations  of 
British  Entomology,  by  James  Francis  Stephens, 
F.L.S.  Horae  Entomologia;,  by  W.  J,  Macleay. 
Entomologia  Britannica,  1  vol.  8vo.  1802,  by  Tho- 
mas Marsham.  Considerations  Generates  sur  l'Ana- 
tomie  comparee  des  Animaux  Articules.par  Hercules 
Straus  Durckheim,  4to.  Paris,  1828.  Modern  Clas- 
sification of  Insects,  by  J.  0.  Westwood,  F.L.S. 

(G.  Newport.) 

INSECTIVORA,  (Insecta,  voro,)  a  group  of 
mammiferous  animals,  considered  by  some  au- 
thors as  a  distinct  order ;  by  others,  and  parti- 
cularly by  Cuvier,  as  a  family  only  of  the  great 
carnivorous  order,  named  by  that  great  natura- 
list Carnassiers.  The  peculiarities  of  struc- 
ture by  which  the  Insectivora  are  characterized 
appear  to  me  to  be  equally  important  with  those 
which  have  led  me  already  to  treat  of  the  Chei- 
roptera as  an  ordinal  group,  and  I  shall  there- 
fore consider  them  in  that  point  of  view. 

They  consist  of  four  very  distinct  groups, 


the  relations  of  which  are  not  very  clearly 
fixed.    I  have  ventured  to  consider  them  as 
four  families,  viz. : — 
Talpid«,  typified  by  the  mole,  Talpa. 
Erinacead*,       by  the  hedgehog,  Erinaceus. 
Soricidje,  by  the  Shrews,  Sorex. 

Tupaiam:,  by  the  genus  Tupaia. 

Such  at  least  appears  to  me,  in  the  present 
state  of  our  knowledge,  to  be  a  near  approach 
to  the  natural  groups  of  which  the  order  i9 
composed.  In  the  Talpida  I  include  the  ge- 
nera Talpa,  Condytura,  and  Chrysochloris ;  in 
the  Soricida,  the  genera  Sorex,  (with  the  sub- 
genera, so  called,  into  which  it  has  lately  been 
subdivided,)  Mygale  and  Scalops,  the  latter 
genus  being  clearly  osculant  between  the 
Soricida  and  the  Talpida ;  in  the  Erinaceadte, 
the  genera  Erinaceus,  Echinops,  and  Centenes ; 
and  m  the  Tupaiada,  the  single  genus  Tupaia, 
or  Cladobates,  as  it  is  named  by  Fred.  Cuvier. 

It  will  at  once  be  seen,  by  reference  to  this 
enumeration  of  the  types  of  form  which  occur 
in  this  order,  that  animals,  differing  greatly  in 
their  general  structure  and  habits,  are  included 
in  it.  But  it  will  also  be  found  that  they  all 
agree  in  the  general  character  of  their  teeth, 
which  are  in  all  instances  furnished  with  ele- 
vated and  pointed  tubercles,  for  the  purpose  of 
breaking  down  the  hard  and  polished  elytra  of 
coleopterous  insects,  upon  which  most  of  them 
in  a  greater  or  less  degree  subsist.  This  cha- 
racter has  already  been  exhibited  in  the  insecti- 
vorous group  of  the  Cheiroptera,  which  we  have 
considered  as  leading  towards  the  present  order ; 
and  even  in  the  lower  forms  of  the  Quadru- 
mana  a  similar  tendency  is  evident,  as  in  the 
Maki,  the  Loris,  and  others.  They  agree,  also, 
in  being  for  the  most  part  nocturnal  animals, 
and,  with  some  exceptions,  in  living  under 
ground,  or  at  least  in  exhibiting  a  tendency  to 
such  a  mode  of  life;  and  all  those  which  in- 
habit the  colder  countries  pass  the  winter  in  a 
state  of  torpidity.  They  all  possess  clavicles ; 
their  limbs  are  generally  short,  and  they  are 
plantigrade.  They  have  ventral  mamms,  the 
stomach  is  perfectly  simple,  and  they  are  desti- 
tute of  a  ccecum. 

The  different  families  which  I  have  named 
are  as  well  characterized  by  their  habits  as  by 
their  external  form,  and  their  more  intimate 
structure.  The  Talpida,  the  teeth  of  which  are 
shewn  in  the  genus  Talpa  (fig.  441,)  and  Chry- 
sochloris (fig.  450),  which  are  pre-eminently 
subterranean,  are  distinguished  by  their  extra- 
ordinary habits  of  forming  long  and  complicated 
burrows  underground,  passing  their  whole  lives 
in  a  subterranean  retreat,  in  which  they  are  born, 
feed,  breed,  hibernate,  and  die ;  and  which  re- 
treat, in  the  case  of  the  common  mole,  is  formed 
with  the  utmost  art,  and  a  beautifully  complica- 
ted construction.  The  Soricidm  (fig.  449)  are 
a  sort  of  carnivorous  mice;  and  although  they  do 
not  actually  burrow,  retreat  during  the  winter, 
and  in  their  ordinary  repose,  into  holes,  feed- 
ing, however,  on  the  surface  or  in  the  water, 
several  of  them  being  partially  aquatic,  diving 
with  facility  after  aquatic  insects,  and  remain- 
ing without  difficulty  a  long  time  under  water. 
In  both  these  families  there  is  a  peculiar  cha- 


INSECTIVORA. 


995 


raeter  in  the  structure  of  the  hair,  which  favours 
the  habits  I  have  mentioned,  and  which  will 
be  presently  described.  In  the  Erinaceada  (see 
fig.  451)  we  still  have  hibernating  animals,  but 
these,  instead  of  burrowing  or  descending  into 
deep  excavations,  conceal  themselves  only  under 
leaves,  or  in  any  superficial  hollow,  and  live 
upon  food  which  they  either  find  upon  the  sur- 
face or  dig  out  of  the  ground  with  their  hard 
moveable  muzzle  ;  the  character  of  their  integu- 
ment is  very  peculiar,  the  hair  being  modified 
into  spines  of  a  greateror  less  degree  of  firmness, 
and  the  animals  being  mostly  capable  of  rolling 
themselves  into  a  ball,  and  thus  presenting  a 
panoply  of  sharp  spines  to  their  enemies.  The 
last-named  group,  which  I  have  named  Tupai- 
ad<e,  (fig.  452)  partake,  as  before  observed, 
of  the  character  of  the  Insectivorous  Quadru- 
mana;  living  in  trees,  which  they  climb  with 
all  the  agility  of  a  monkey  or  a  squirrel.  They 
consist  but  of  a  single  genus,  named  by  the  late 
Sir  Stamford  Raffles,  Tupaia,  of  which  three 
species  are  well  distinguished.  They  are  na- 
tives of  Java. 

I.  Osteology. — It  can  scarcely  be  said  that 
there  is  any  peculiarity  of  structure  in  the  ske- 
letons of  the  whole  of  the  insectivora,  in  which 
they  differ  essentially  from  other  groups  ;  but 
on  the  other  hand,  there  are  many  in  which 
they  differ  from  each  other,  according  to  the 
very  striking  and  obvious  diversity  of  their  ha- 
bits. In  the  family  Talpida,  the  genus  Tulpa 
(fig.  440)  presents  itself  as  the  type.  In  these 
animals  the  cranium  is  greatly  elongated,  and 
of  a  tapering  or  conical  form,  a  character 
which  it  partakes  with  the  Soricida,  but  to 
a  still  more  remarkable  degree.  The  cra- 
nium of  the  Chrysochloris,  or  Cape-mole,  the 
South  African  representative  of  this  family, 
presents  this  character  in  the  most  regular 
form.  It  is,  in  fact,  a  perfect  cone,  short,  pointed 
at  the  muzzle,  broad  behind,  where  the  base  of 
the  cone  is  distinctly  circumscribed  by  a  crest, 
which  passes  from  the  root  of  the  zygomatic 
arch  of  one  side,  over  the  vertex,  to  the  cor- 
responding point  on  the  other;  on  the  sides  of 
the  head  the  zygomatic  arches  themselves  com- 
plete the  cone,  passing  obliquely  and  in  a 
straight  line  from  the  maxillary  to  the  temporal 
bone,  and  beneath  it  is  completed  by  the  in- 
clination inwards  of  the  symphysis,  the 
rami,  and  the  coracoid  processes  of  the  lower 
jaw.  The  portion  posterior  to  the  base  of  the 
cone  is  rounded. 

In  the  genera  Talpa(figAAi)  and  Condijtura 
the  head  is  equally  but  less  regularly  conical, 
and  the  snout  is  more  elongated;  the  zygomatic 


Fig.  441. 


arch  is  extremely  slender,  and  rises  obliquely, 
joining  the  cranium  considerably  above  the  audi- 
tory meatus.  A  similar  conformation  is  seen  in  the 
genus  Scalops,  which  I  have  already  mentioned 
as  leading  from  the  Talpida  to  the  Soricida. 
This  form  is  admirably  suited  for  their  subter- 
ranean progression,  as  they  push  their  way 
through  the  soil  by  their  long  moveable  snout, 
which  acts  in  some  measure  as  a  wedge. 
Amongst  the  Soricidce,  the  Scalops  approaches 
in  its  structure  most  nearly  to  the  Talpida, 
having  the  almost  perfectly  conical  form  of  the 
head  which  belongs  to  that  family ;  and  all  the 
Soricida  partake  of  it  to  a  greater  or  less  degree. 
But  the  cranium  of  the  Erinaceadtz  approaches 
more  nearly  to  that  of  the  Carnivora ;  and 
viewed  from  above,  the  sides  are  nearly  parallel, 
the  zygomatic  arches  projecting  further  than  the 
posterior  part  of  the  cranium.  The  muzzle 
is  shorter,  more  obtuse,  and  somewhat 
narrower  than  the  cranium,  which  is  com- 
pressed forwards.  In  Centenes  the  head  is 
much  more  elongated  and  conical.  The  genus 
Tupaia  has  the  head  nearly  oval,  the  muzzle 
straight,  prominent,  much  smaller  than  the  cra- 
nium, the  zygomatic  arches  but  slightly  pro- 
minent, and  the  circle  of  the  orbit  closed  pos- 
teriorly, a  circumstance  which  is  not  found  in 
any  other  of  the  order  Insectivora.    In  this 


Fig.  440. 


996 


INSECTIVORA. 


genus  the  orbit  is  therefore  circumscribed  by 
being  closed  posteriorly  by  the  union  of  the 
post-orbitar  processes  of  the  frontal  and  jugal 
bones  ;  in  all  the  other  genera  the  orbit  and  the 
temporal  fossa  are  confounded  in  one  cavity, 
without  the  trace  of  any  attempt  at  forming  a 
division  between  them.  This  peculiarity  in  the 
genus  Tupaia  shews  a  marked  tendency  to- 
wards the  insectivorous  Quadrumana. 

The  bones  of  the  face  are  very  early  united 
in  the  Talpida  and  the  Soricidee.  In  the 
genus  Centenes  there  is  no  jugal  bone.  There 
is  therefore  no  zygomatic  arch,  notwithstanding 
the  masseter  muscle  is  of  great  size.  This  is 
attached  by  a  single  tendon  to  a  sort  of  tu- 
bercle, which  represents  the  zygomatic  process 
of  the  maxillary  bone.  In  Tupaia  the  inter- 
maxillary bones  are  very  large,  and  their 
suture  descends  vertically,  nearly  half  way  be- 
tween the  nares  and  the  orbits.  The  Shrews, 
like  Centenes,  have  no  malar  bone,  and  the 
zygomatic  process  of  the  maxillary  is  even  less 
conspicuous  than  in  the  former  genus.  Most 
of  the  subterranean  forms  have  at  the  extremity 
of  the  muzzle,  that  is  to  say,  around  the  open- 
ing of  the  nares,  a  small  rim  or  border,  which 
is  especially  conspicuous  in  the  Chrysochloris, 
for  the  attachment  of  the  large  and  moveable 
cartilages  of  the  nose,  so  important  to  these 
animals  in  turning  aside  the  earth  as  they  make 
their  way  through  the  ground,  as  well  as  in 
seizing  the  worms  and  insects  on  which  they 
feed. 

The  proportions  of  the  spine  vary  greatly  in 
the  different  families  of  Insectivora,  as  may  be 
anticipated  from  the  great  difference  in  their 
habits.  On  this  subject  it  may  not  be  useless 
to  subjoin  the  following  table  of  the  numbers 
of  the  separate  classes  of  vertebrae,  which  is 
taken  from  the  last  edition  of  the  Lecons  d'Ana- 
tomie  Comparee  of  Cuvier : — 


0 

— 

E 
a 

"3 

>J. 

o 
o 

Toti 
cerv 

B 

J 

M 

u 

Erinaceus  Europaius  (Hedge- 

15 

6 

3 

12 

43 

Centenes  ecaudatus  (Tenrec) . 

15 

5 

3 

10 

40 

1-1 

7 

3? 

9 

40 

13 

7 

2 

25 

54 

Sorex  araneus  (Shrew)  .... 

14 

6 

5? 

14 

46 

S.  fodiens  (Water-shrew)  .  . 

13 

6 

5 

17 

48 

ChrysochlorisCapensis  (Cape 

19 

3 

5 

5 

39 

Talpa    Europ&a  (common 

mole)  

13 

6 

6 

11 

43 

T.  caca  (blind  mole)  

14 

.r. 

5 

1 1 

42 

Condytura  cristata  (radiated 

mole  

13 

6 

5 

17 

48 

Scalops  (mole-shrew)  

12 

7 

(3 

10 

42 

It  is  worthy  of  remark,  in  taking  a  compara- 
tive glance  at  this  list,  that  the  length  of  the 
tail  in  the  different  species  is  in  exact  accord- 
ance with  their  habits,  as  far  at  least  as  we  are 
acquainted  with  them.     Thus,  in  Tupaia,  we 


observe  a  tail  as  long  as  that  of  a  squirrel,  and 
obviously  for  the  same  object,  that  of  balanc- 
ing the  animal  when  taking  leaps  from  one 
branch  to  another ;  and  in  the  Water-shrew  the 
tail  is  lengthened  to  assist  in  swimming,  for 
which  purpose  it  is  also  fringed  on  each  side 
with  stiff  hairs.  Of  the  habits  of  the  Condy- 
tura* we  know  little,  and  of  that  little  nothing 
which  accounts  for  the  considerable  proportion 
of  the  tail. 

Of  the  form  of  the  different  vertebra?  in  the 
various  groups  of  the  Insectivora,  little  need 
be  said,  as  there  are  few  circumstances  con- 
nected with  these  bones  which  bear  materially 
upon  any  physiological  point.  It  may  be  ob- 
served, however,  that  in  the  Talpida  and  the 
Soricida  the  cervical  vertebrae  form  large  rings, 
have  strong  transverse  processes,  and,  except- 
ing the  second,  do  not  possess  any  spinous 
processes.  In  the  Erinuceadte,  and  particu- 
larly in  the  Tenrec  (Centenes )  the  transverse 
processes  are  particularly  large,  and  the  rings 
smaller  than  in  the  former  families.  The  spi- 
nous processes  are  also  wanting  in  the  dorsal 
vertebra?  of  the  mole. 

The  sternum  offers  some  peculiarities 
worthy  of  notice.  In  the  mole  the  first  ster- 
nal bone  is  very  large  and  compressed.  To  its 
anterior  pointed  extremity  the  thick  short 
clavicles  are  attached,  and  further  back  to  the 
same  bone,  the  first  rib  is  articulated ;  to  the 
second  bone  is  fixed  the  second  rib,  and  there 
succeed  to  these  three  elongated  bones  of  the 
ordinary  form,  to  each  of  which  two  pairs  of 
ribs  are  articulated  ;  then  a  small  bone,  to  which 
one  pair  of  ribs  is  fixed,  and  then  the  xiphoid 
bone,  which  is  long  and  narrow. 

In  the  Chrysochloris  the  first  bone  of  the 
sternum  is  equally  compressed  but  less  elevated ; 
and  the  anterior  half  is  furnished  on  the  up- 
per part  with  two  small  aliform  processes, 
which  are  concave,  and  support  the  first  two 
ribs,  which  are  extremely  broad;  the  long 
slender  clavicles  are  attached  at  its  anterior 
point;  and  then  follow  seven  other  oblong 
pieces,  and  an  elongated  xiphoid  bone,  which 
bears  at  its  posterior  extremity  a  semilunar  car- 
tilaginous dilatation. 

The  ribs  in  the  mole  and  its  congeners  are 
nearly  all  of  the  same  length,  giving  that  pe- 
culiar cylindrical  form  to  the  body  which  cha- 
racterises these  animals,  and  which  is  so  essen- 
tial to  their  habits ;  and  in  the  Chrysochloris  the 
first  rib  is  very  much  broader  than  the  others. 

But  it  is  in  the  bones  constituting  the  anterior 
extremities,  that  the  most  remarkable  and  in- 
teresting peculiarities  exist  in  some  of  the 
families  of  this  group.  In  the  mole  especially, 
the  anterior  extremity  (fig.  442)  exhibits  one  of 
the  most  extraordinary  modifications  to  be  found 
in  the  whole  of  the  Mammifera.  The  clavicle 
is  fully  developed  in  the  whole  of  the  Insec- 
tivora.    In  the  mole  (b)  it  offers  the  most 

*  From  the  name  condytura,  given  to  this  genus 
by  Illiger,  it  might  be  inferred  that  the  tail  is 
furnished  with  knotty  tuberosities  ;  this,  however, 
is  only  seen  in  dried  specimens,  which  doubtless 
furnished  to  Illiger  the  characters  of  the  genus, 
and  suggested  its  name. 


INSECTIVORA. 


997 


Fig.  442 


abnormal  deviation  from  the  usual  construc- 
tion. It  is  extremely  short  and  broad,  forming 
in  fact  nearly  a  square  ;  about  the  middle  of  its 
anterior  margin  a  strong  process  rises,  which 
gives  origin  to  the  subclavian  muscle,  which  in 
this  animal  is  greatly  developed.  It  is  articu- 
lated, as  usual,  with  the  sternum  by  its  interior 
extremity,  which  may  here  be  more  properly 
called  its  interior  margin ;  but  by  its  external 
margin  it  is  connected  moveably  with  the  head 
of  the  humerus,  which  connection  is  rendered 
more  solid  towards  the  anterior  part  by  a  strong 
ligament.  Its  connexion  with  the  acromion  of 
the  scapula  is  by  a  ligament  merely,  which 
extends  from  the  acromion  to  the  posterior  and 
outer  angle  of  the  clavicles.  In  Condytura  and 
even  in  Scalops  the  construction  of  this  bone  is 
on  a  similar  type;  but  in  Clirysochloris  it  is 
long  and  slender  as  in  the  other  Tnsectivora. 

The  scapula  (a)  in  the  mole  is  no  less  singu- 
larly formed  than  the  bone  just. described.  It  is 
elongated  to  an  extraordinary  degree,  being  not 
less  than  six  times  as  long  as  it  is  broad  at  the 
broadest  part,  which  is  at  the  superior  extremity. 
Towards  the  middle  it  is  contracted  and  almost 
cylindrical ;  and  the  spine,  which  runs  nearly 
the  whole  length  of  the  bone,  is  at  this  part 
almost  effaced.  The  acromion,  as  before  ob- 
served, has  only  a  ligamentous  connexion  with 
the  clavicle.  In  Condytura  and  Scalops  the 
construction  of  this  bone  is  somewhat  similar, 
and  in  Chrysochloris  it  is  also  of  considerable 
length. 

The  humerus  in  the  mole  (Jigs.  442,  c,  443) 
is  of  so  extraordinary  a  form,  that  were  it 
examined  alone,  isolated  from  its  natural  con- 
nexions, it  would  be  impossible  to  detect 


its  true  character  It  is  of  a  square  form, 
extremely  broad  at  the  superior  part,  where 
it  presents  two  articular  surfaces;  the  an- 
terior is  very  broad,  slightly  convex ;  the 
posterior  and  internal  is  narrow,  but  more 
convex  than  the  former ;  by  the  first  it  is 
articulated  to  the  clavicle,  and  by  the  latter 
to  the  scapula.  Between  the  former,  which 
may  be  considered  as  appertaining  to  the 
greater  tuberosity  of  the  bone,  and  the  head,  is 
a  deep  fossa.  The  body  of  the  bone  is  short, 
thick,  and  very  broad,  and  is  curved  upwards, 
so  that  its  articulation  with  the  forearm  is 
placed  actually  higher  than  the  shoulder,  and 
the  palm  of  the  hand  is  consequently  turned 
outwards.  In  Chrysochloris  the  form  of  this 
bone  is  not  less  remarkable.  It  is  somewhat 
longer  than  that  of  the  mole ;  its  articulation 
with  the  forearm  constitutes  half  a  sphere ;  and 
the  inner  condyle  is  so  elongated  and  inclined 
downwards,  that  the  whole  bone  forms  an  arch 
of  which  the  convexity  is  turned  outwards. 
This  condyle  is  articulated  with  a  bone,  which 
must  be  considered  as  a  most  extraordinary 
modification  of  the  ospisiforme,  which  is  as  long 
as  the  radius,  so  that  in  fact  the  forearm  may  be 
said  to  be  composed  of  three  bones. 

The  bones  of  the  forearm  (Jig. 442,  d,e)  in  the 
extraordinary  animal  which  offers  so  many  de- 
viations from  typical  structure,  the  mole,  are 
no  less  remarkable  than  those  of  the  shoulder. 
The  ulna  is  very  broad  and  much  flattened  ;  its 
superior  extremity  is  enlarged  transversely,  the 
anterior  surface  concave,  the  posterior  convex. 
The  radius  is  separated  by  a  considerable  in- 
terval from  the  ulna  throughout  their  length, 
and  the  two  bones  are  only  united  at  the  upper 
extremity  by  a  capsular  ligament.  But  the 
articular  surfaces  of  the  two  bones  are  flat,  and 
the  head  of  the  radius  is  prolonged  into  a  hook- 
like process,  forming  a  sort  of  radial  olecranon, 
so  that  rotation  is  impossible.  The  carpal  bones 
(Jig.444)  consist  of  two  series  of  five  in  each,  and 
an  additional  bone  of  a  very  peculiar  construc- 
tion. This  is  a  large  sickle-shaped  or  falciform 
bone,  having  the  convex  margin  outwards ;  it 
extends  from  the  carpal  extremity  of  the  radius 
to  the  first  metacarpal  bone.  It  is  this  bone 
which  gives  the  great  breadth  to  the  hand, 
which  is  so  important  to  this  animal  in  its 
peculiar  mode  of  life. 

The  phalanges  of  the  fingers  are  very  short, 
and  covered  by  the  integument  in  such  a 
manner  as  to  appear  to  belong  to  the  meta- 


Fig.  443. 


Fig.  444. 


998 


INSECTIVORA. 


carpal  portion  of  the  hand ;  and  it  is  only  the 
long  sharp  nails  which  extend  beyond  the  skin, 
and  are  externally  visible. 

The  position  then  of  the  anterior  extremity 
of  the  animal  is  this  :  the  humerus  is  so  placed 
that  the  inferior  or  distal  extremity  is  the  most 
raised,  so  that  the  fore-arm  is  kept  in  a  state 
between  pronation  and  supination,  the  elbow 
raised,  the  radius  and  the  thumb  placed  down- 
wards, and  the  palm  of  the  hand  directed  out- 
wards. When-  to  this  we  add  the  peculiar 
flexion  of  the  last  phalanx  of  the  fingers  with 
the  enormous  nails,  we  have  a  fossorial  struc- 
ture not  equalled  by  any  other  in  the  whole 
of  the  vertebrated  animals,  and  only  imitated 
by  the  no  less  remarkable  anomaly  amongst 
insects,  the  Gryllotalpa  or  mole-cricket. 

In  Chrysochloris  the  third  and  fourth  fingers 
are  united  by  one  large  powerful  nail,  and  are 
developed  to  an  extraordinary  size  (fig.  445), 


Fig.  445. 


the  fifth  finger  being  reduced  to  a  minute  ru- 
diment; and  the  carpal  bones  are  placed  in  an 
abrupt  curve,  so  that  the  outer  side  of  the  fifth 


finger  approaches  the  first.  The  os  pisiforme  as- 
sumes also  a  peculiar  development,  being  very 
much  elongated,  rises  in  the  direction  of  the 
forearm,  and  is  actually  articulated  with  the 
internal  condyle  of  the  humerus. 

The  pelvis  in  the  Talpida  and  Soricidee  is 
extremely  long.  The  ilia  are  narrow  and 
pointed  at  the  anterior  part.  In  the  last-named 
family,  the  pubis  and  the  ischium  are  especially 
long  and  narrow.  In  Chrysochloris,  on  the 
contrary,  the  ischium  is  very  broad. 

The  femur  offers  but  few  and  unimportant 
particularities  amongst  the  Insectivora,  unless 
it  be  that  there  is  in  the  mole  and  Chrysochloris 
a  sort  of  third  trochanter;  a  process  which  is  also 
found  in  some  of  the  lower  Quadrumana,  and 
in  some  other  of  the  Mammifera.  The  fibula 
is  united  to  the  tibia  for  nearly  the  inferior  third 
of  their  length,  in  the  Talpida,  the  Soricida, 
and  the  Erinaceada.  In  the  mole  this  union 
is  to  a  greater  extent  than  perhaps  in  any  other 
animal  of  the  Mammiferous  class. 

The  hinder  feet  in  the  whole  of  this  order 
are  plantigrade.  In  the  mole,  as  Daubenton 
and  Meckel  have  observed,  there  is  an  addi- 
tional tarsal  bone,  to  those  which  are  ordinarily 
found.  It  is  of  considerable  size,  and  seems  to 
answer  to  the  falciform  bone  of  the  anterior 
extremities  already  described.  It  is  of  an 
uniform  shape,  of  considerable  size,  and  is  arti- 
culated between  the  scaphoid  and  the  first 
cuneiform  bone,  and  extends  forwards  along 
the  first  metatarsal. 

II.  Muscles. — The  extraordinary  develope- 
ment  of  the  bones  of  the  anterior  extremity  in 
the  mole,  will,  of  course,  be  associated  with 
a  no  less  remarkable  structure  in  the  muscles 
of  the  same  part ;  and  the  known  habits  of  the 
animal  will  account  equally  for  the  necessity 
of  such  a  structure  in  both.  I  give  a  figure 
of  the  muscles  of  the  anterior  extremity  and 
of  the  anterior  part  of  the  trunk  from  Cams. 
(Fig.  446.) 


Fig.  446. 


INSECTIVORA. 


999 


The  cervical  portion  of  the  serratus  magnus 
is  simple,  excessively  thick  and  swelling,  and 
is  attached  only  to  the  posterior  vertebra?.  The 
trapezius  consists  only  of  two  bundles  of 
fleshy  fibres,  which  arise  from  the  lumbar  ver- 
tebra, and  are  inserted  into  the  posterior  ex- 
tremities of  the  long  and  narrow  scapula ;  and 
as  these  fasciculi  are  nearly  parallel,  their 
action  would  be  rather  to  separate  than  to  ap- 
proximate the  posterior  parts  of  these  bones, 
were  it  not  for  a  strong  transverse  ligament 
which  holds  them  together.  Their  application 
consists  in  moving  the  anterior  part  of  the  body 
upwards.  The  scapular  attachments  of  the 
rhomboideus  are  principally  to  this  transverse 
ligament  of  the  two  scapulae,  and  as  it  is  in- 
serted into  a  sort  of  ossified  modification  of  a 
cervical  ligament,  its  office  consists  in  raising 
the  head  with  great  force.  The  levator  scapula 
is  wanting ;  its  existence  would  be  obviously 
useless.  The  pectorulis  minor  is  very  slender  ; 
it  is  attached  to  the  anterior  parts  of  the  first 
ribs,  and  to  the  ligament,  already  mentioned, 
which  joins  the  clavicle  to  the  scapula.  There 
are  also  two  muscles  arising  from  the  anterior 
part  of  the  sternum,  and  inserted  into  the  large 
head  of  the  clavicles. 

The  most  important  muscles  of  the  humerus 
are  the  pectorulis  major,  the  latissimus  dorsi, 
and  the  teres  major,  all  of  which  are  of  great 
size ;  and  it  is  by  means  of  these  muscles  that 
the  astonishing  efforts  of  the  animal  are  made 
in  excavating  his  passages,  and  throwing  the 
earth  behind  him.  The  pectorulis  major  is  of 
extraordinary  thickness.  It  is  formed  of  six 
portions,  which  are  all  of  them  inserted  into 
the  broad  quadrate  portion  of  the  humerus. 
Four  of  these  portions  arise  from  the  sternum, 
the  fifth  from  the  clavicle ;  and  the  sixth  passes 
across  transversely  from  one  arm  to  the  other. 
The  latissimus  dorsi  is  also  of  considerable  size, 
and  is  inserted  into  the  posterior  surface  of  the 
quadrate  portion  of  the  humerus.  The  teres 
major,  which  is  of  enormous  thickness,  is  in- 
serted near  the  former  muscle. 

The  other  muscles  of  the  anterior  extremity 
do  not  require  particular  description. 

There  is  one  peculiarity  in  the  muscular  sys- 
tem which  deserves  special  notice;  it  is  the 
enormous  developement  of  the  punniculus  cur- 
nosus  in  the  hedgehog,  by  which  it  is  enabled 
to  roll  itself  up  in  a  ball  with  such  astonishing 


force  as  to  afford  with  its  spiny  covering  a 
complete  protection  against  its  most  powerful 
antagonists.  I  proceed  to  describe  this  ap- 
paratus and  its  uses. 

As  this  muscular  apparatus  has  no  attach- 
ment but  to  the  skin,  it  changes  its  position 
with  every  movement  of  the  integument ;  and 
it  is  therefore  necessary  to  consider  it  under 
the  various  relations  which  it  assumes  in  the 
different  positions  of  the  animal.  Considering 
it  then,  in  the  first  place,  as  rolled  up  in  a  ball 
(fig.  447),  either  for  defence  or  during  repose, 


Fig.  447. 


the  whole  body  is  enveloped  beneath  the  skin 
by  a  strong  sac  or  covering,  consisting  of  a 
mass  of  fleshy  and  concentric  muscular  fibres, 
of  an  oval  form.  All  these  fibres  are  attached 
intimately  to  the  skin,  and  even  to  the  base  of 
the  spines  with  which  it  is  every  where  furnished, 
so  that  it  is  even  difficult  to  detach  the  fibres  in 
dissection.  The  thickest  part  of  this  fleshy  sac 
is  at  the  lower  margin  or  mouth  of  the  sac, 
at  which  part  it  forms  a  sort  of  sphincter,  com- 
posed of  orbicular  muscular  fibres.  On  the 
other  hand,  when  the  hedge-hog  is  unrolled, 
and  at  its  full  length  (fig.  448),  the  muscle  in 
question  totally  changes  its  figure  and  relations. 
The  muscle  now  lies  over  the  back,  forming  an 
oval  covering,  the  middle  of  which  is  very  thin, 


Fig.  448. 


1000 


INSECTIVORA. 


and  the  circumference  exceedingly  thick  and 
somewhat  raised.  To  different  portions  of  this 
circumference  of  the  muscular  covering  are 
attached  several  accessory  muscles.  Anteriorly 
there  are  two  pairs ;  one  arising  from  the  me- 
dian line  and  inserted  into  the  nasal  bone ;  the 
other,  more  external,  apparently  confounded  at 
its  origin  with  the  external  orbicular  fibres,  is 
inserted  into  the  side  of  the  nose  and  incisive 
bones.  Posteriorly  a  pair  of  broad  muscles, 
of  a  pyramidal  form,  arise  from  the  posterior 
part  of  the  fleshy  circumference,  and  are  in* 
serted  into  the  side  of  the  tail  towards  the  ex- 
tremity. 

On  the  ventral  aspect  there  are  also  several 
portions  of  muscle,  belonging  to  the  same  ap- 
paratus. There  is  one  beneath  the  throat,  aris- 
ing from  the  anterior  part  of  the  thorax,  under 
the  skin,  and  is  inserted  about  the  lateral  parts 
of  the  head  near  the  ears.  Another  arises  from 
the  median  line  of  the  sternum,  and  passes 
obliquely  forwards  over  the  shoulders,  in  front 
of  them,  to  join  the  margin  of  the  great  or- 
bicular muscle  before  described.  There  is 
another  ventral  portion  which  has  a  very  ex- 
tended connexion.  It  is  attached  around  the 
anus,  to  the  lateral  parts  of  the  tail  and  neigh- 
bouring parts,  extends  over  the  whole  surface 
of  the  abdomen,  and  then  divides  into  two 
portions;  one  internal,  and  larger  than  the  other, 
passes  under  the  axilla,  and  is  inserted  into 
the  superior  and  interior  part  of  the  humerus ; 
the  other,  external,  passes  laterally  upwards,  to 
be  inserted  into  the  margin  of  the  great  or- 
bicular muscle  near  the  neck.  The  muscles 
hitherto  described  lie  superficially ;  but  there 
are  others  which  are  seated  underneath  the 
great  muscle  of  the  back.  One  arises  from  the 
side  of  the  head,  being  attached  to  the  meatus 
auditorius  on  each  side,  and  loses  itself  in  the 
anterior  point  of  the  orbicular  muscle.  There 
is  also  a  thin  layer  of  fibres  lying  beneath  the 
great  muscle,  of  which  the  anterior  are  attached 
to  the  superior  interior  portion  of  the  humerus, 
and  the  posterior  to  the  third  ventral  muscle 
already  mentioned. 

We  have  here  a  very  extensive  and  a  very 
powerful  apparatus,  and  it  now  becomes  ne- 
cessary to  consider  its  application.  When  the 
hedgehog  is  rolled  up  in  a  ball,  it  is  com- 
pletely enveloped,  as  regards  all  the  upper  and 
lateral  parts  of  the  body,  in  the  great  orbicular 
muscle.  When  once  brought  into  this  position 
the  simple  contraction  of  the  thick  circum- 
ference of  the  muscle,  which  forms  a  true 
sphincter,  is  sufficient  to  retain  it.  If  the  ani- 
mal unrolls  itself,  the  disc  of  the  great  muscle 
contracts  whilst  the  circumference  is  relaxed, 
allowing  the  exit  of  the  feet  and  the  uncover- 
ing of  the  belly  and  sides :  then  the  whole 
muscle  contracts  together,  and  lies  in  a  mass 
on  the  back.  By  this  universal  contraction, 
the  necessary  muscles  become  stretched,  and 
in  a  condition  to  perform  their  several  offices; 
by  the  contraction  of  the  anterior  ones  the  head, 
and  by  that  of  the  posterior  the  tail,  is  raised, 
whilst  those  which  lie  beneath  raise  the  head 
and  neck  together,  and  the  animal  is  now 
ready  for  progression.    On  the  other  hand,  on 


the  apprehension  of  danger,  or  when'  reposing, 
it  rolls  itself  into  a  ball  by  the  following  pro- 
cess. The  orbicular  muscle  relaxes,  and  the 
muscles  extending  from  it  to  the  head  and  to 
the  tail  extend  it  in  those  directions,  whilst  the 
deap-seated  transverse  muscles  which  are  at- 
tached to  the  external  lateral  portions,  and  lie 
on  the  belly,  bring  this  part  of  the  circum- 
ference downwards.  At  the  same  time  the 
head  is  brought  downwards  towards  the  breast 
by  the  ordinary  flexion  of  the  head,  and  by  the 
cutaneous  muscles  of  the  neck  already  de- 
scribed; the  tail  and  the  hinder  legs  are  brought 
forwards  under  the  belly,  and  the  flexors  of  the 
limbs  contract.  The  great  orbicular  muscle 
passes  downwards  over  the  sides,  then  contracts 
at  the  circumference,  and  forms  a  sort  of  sac  or 
purse,  enveloping  the  whole  body  and  limbs. 

III.  Digestive  organs. — It  is,  of  course,  in 
the  structure  of  the  digestive  organs,  and  par- 
ticularly in  that  of  the  teeth,  that  we  find  the 
distinguishing  characters  of  the  whole  order ; 
yet  so  nearly  do  these  organs  in  the  Insecti- 
vora  approximate  to  those  in  the  insectivorous 
division  of  the  Cheiroptera,  that  it  would  not 
have  been  possible  to  separate  the  two  groups, 
had  there  been  no  other  important  points  of 
distinction.  From  the  insectivorous  Quadru- 
mana  they  are  distinguished  by  the  planti- 
grade character  of  the  posterior  extremities; 
from  the  bats  by  the  whole  structure  of  the 
limbs,  and  from  all  the  true  Carnivora  by  the 
tuberculated  teeth. 

There  is  no  inconsiderable  difficulty  in  as- 
signing the  various  anterior  teeth  in  the  Insec- 
tivora  to  their  proper  classes.  In  most  of  the 
genera,  according  to  the  statement  of  both  the 
Cuviers  and  others,  there  are  no  canine  teeth, 
and  the  false  molares  are  very  numerous ;  but 
it  is  in  many  cases  doubtful  whether  the  an- 
terior false  molares,  as  they  are  termed  by 
these  anatomists,  be  not  theoretically  canines 
modified  in  their  form.  On  this  point,  how- 
ever, there  is  no  possibility  of  coming  to  a 
satisfactory  conclusion,  as  every  one  will  at 
last  form  his  own  opinion  on  each  case;  I  shall 
therefore  follow  the  arrangement  of  Frederic 
Cuvier  as  the  most  generally  known,  and, 
upon  the  whole,  by  far  the  best  authority  on 
the  teeth  of  the  Mammifera. 

The  incisive  teeth  vary  greatly  in  the  dif- 
ferent genera.  In  Mi/gale,  in  Scalops,  and  in 
Condytura,  there  is  in  the  upper  jaw  but  a 
single  incisor  on  each  side,  which  is  very  strong 
and  of  a  triangular  form.  In  the  first  of  these 
genera  it  is  somewhat  curved  downwards  and 
backwards,  and  slightly  resembles  that  of  some 
Rodentia.  In  Sorex  (JigA49)  it  is  also  single, 
very  strong,  curved,  and  similar  to  the  canine 
tooth  in  the  Carnivora,  but  furnished  with  a 
strong  tooth-like  process  posteriorly,  appearing 
almost  like  a  distinct  tooth. 

In  Talpa  (jig.  441)  there  are  three  superior 
incisores  on  each  side,  which  are  small  with 
cutting  edges,  like  those  of  the  Carnivora.  In 
Chrysockloris  (fig.  450),  the  single  superior 
incisor  is  curved,  convergent,  obliquely  trun- 
cate and  pointed;  and  in  Erinaceus  (fig. 451) 
there  are  three  pairs,  of  which  the  first  is  large, 


Fig.  4-49.  Sorex 

1 


INSECTIVORA.  100  L 

Fig.  451.  Erinaceus. 


Fig.  450.  Chrysochloris. 


Fig.  452.  Tupaia. 


obtuse,  and  strong,  separated  by  a  considerable 
interval  from  its  fellow,  and  convergent  with 
it.  The  others  are  small  and  resemble  false 
molares.  In  Tupaia  (fig.  452)  these  teeth 
are  two  on  each  side,  distant  from  each  other, 
and  from  the  first  false  molar.  The  inferior 
incisores  also  vary  greatly  in  their  form  and 
number.  In  Scalops  there  are  two,  the  first 
small,  the  second  larger  and  resembling  in  form 
a  canine  tooth.  In  Condytura  there  are  two, 
rounded  in  front,  flattened  behind.  In  Talpa 
there  are  four  similar  to  those  of  the  upper  jaw, 
and  in  Sorex  there  is  one  only  of  a  very  pecu- 
liar form  :  it  is  very  long  from  the  anterior  to 
the  posterior  part,  somewhat  hooked,  pointed, 
and,  in_  some  species,  the  edge  is  notched  or 


trifid.  There  are  no  true  canines,  according  to 
the  opinion  of  Frederick  Cuvier,  in  any  of 
these  animals,  excepting  Condytura,  Talpa, 
(in  which  they  exist  in  the  upper  jaw  only) 
Centenes,  and  Tupaia.  The  first  tooth  be- 
yond the  incisores,  considered  by  Fred.  Cuvier 
as  the  first  false  molar  in  the  lower  jaw  in  the 
mole,  is  by  Baron  Cuvier  termed  the  canine.  In 
Centenes  these  teeth  are  of  the  normal  form  ; 
and  in  fact  the  general  arrrangement  of  the 
teeth  in  this  genus  indicates  a  marked  approach 
towards  the  Carnivora.  In  Condytura  the  su- 
perior canine  is  strong  and  large ;  the  inferior 
merely  rudimentary. 

The  molares,  as  in  the  other  Zoophaga,  are 
divided  into  false  and  true.    Those  of  the 


1002 


INSECTIVORA. 


former  class  are  very  numerous  and  of  very 
various  form  in  the  different  genera,  and  the 
great  diversity  of  number  in  the  molar  teeth 
depends  in  most  cases  upon  these,  the  true 
molares  being  but  three  on  each  side  both 
above  and  below  in  all  the  genera,  excepting  in 
Chrysochloris,  in  which  they  are  f:§,  in  Eri- 
naceus,  in  which  they  are  and  in  Centenes 
In  Chrysochloris  the  true  molares  are 
very  curiously  and  beautifully  formed :  they 
are  much  compressed  from  before  backwards, 
of  a  three-sided  form,  each  of  the  angles  ter- 
minating in  a  sharp  elevated  point ;  thus,  in 
those  of  the  upper  jaw,  there  are  two  situated 
externally  and  one  internally,  and  in  the  lower 
jaw  one  externally  and  two  internally.  The 
whole  of  the  true  molares,  in  all  the  Insecti- 
vora,  are  formed  of  three-sided  prisms,  either 
single  or  double,  and  surmounted  by  acute 
tubercles. 

The  salivary  glands  are  generally  much  de- 
veloped in  the  Insectivora.  In  the  hedgehog 
the  parotids  are  larger  than  the  submaxillary ; 
the  sublingual  are  placed  in  two  rows,  of 
which  the  larger  is  situate  nearest  to  the  lower 
jaw.  In  the  mole  these  glands  are  very  large ; 
the  parotids  are  of  an  oblong  shape,  and  the 
maxillary  are  formed  of  several  rounded  and 
detached  lobes.  In  Sorex  the  maxillary  glands 
are  of  larger  size  than  the  parotids,  and  the 
latter  are  situated  very  low  to  accommodate 
the  oblique  direction  of  the  auditory  canal. 

The  form  of  the  stomach  in  this  Order  of 
animals  is  perfectly  simple,  and  does  not  greatly 
vary  in  the  different  genera.  It  is  situated 
transversely  with  regard  to  the  axis  of  the  body, 
is  somewhat  elongated,  and  the  two  orifices  are 
distant  from  each  other,  as  in  many  of  the 
Carnivore,  and  in  the  insectivorous  bats. 
The  cardiac  pouch  is  generally  distinct  and 
rounded;  the  pyloric  extremity,  on  the  con- 
trary, is  conical  and  perfectly  even.  In  Erina- 
ceus  the  cardiac  point  is  considerable,  the  en- 
trance to  the  oesophagus  being  at  no  great  dis- 
tance from  the  pylorus ;  and  the  internal  coat 
forms  numerous  ruga  and  folds.  This  form  of 
the  stomach  and  the  existence  of  plicae  must  be 
considered  as  indicating  an  aberration  from  the 
insectivorous  type,  and  a  certain  degree  of  ap- 
titude for  the  digestion  of  vegetable  matters, 
and  we  find  accordingly  that  this,  with  a  slight 
exception  or  two,  is  the  only  family  of  the 
Insectivora  which  can  exist  upon  any  but  the 
most  exclusive  animal  aliment.  The  mole,  the 
Chrysochloris,  and  all  their  congeners,  are  in 
this  latter  case;  but  the  hedgehog,  as  is  well 
known,  will  readily  eat  various  vegetable  sub- 
stances, and  often  digs  under  the  common 
plantain  for  the  purpose  of  obtaining  the  roots, 
of  which  it  appears  to  be  very  fond.  The  sto- 
mach varies  a  little  in  its  form  in  the  different 
genera  of  the  Soricida.  In  the  great  shrew  of 
India  it  is  transverse,  the  pyloric  portion  coni- 
cal, of  moderate  dimensions,  the  cardiac  pouch 
small  and  the  two  orifices  distant;  a  form 
which  indicates  an  exclusive  aptitude  for  insect 
food;  but  it  would  appear  that  the  water-shrews 
( Hydrosorex )  must  occasionally  have  recourse 
to  some  kind  of  vegetable  diet,  as  the  pyloric 


portion  is  so  much  elongated  as  to  resemble  in 
some  degree  that  of  the  Pteropida  or  fruit- 
eating  Cheiroptera,  exhibited  in  Jig.  287,  vol.  i. 
p.  600.  In  the  mole  the  oesophagus  enters  at 
about  the  middle  of  its  anterior  margin,  and 
the  lesser  curvature  is  nearly  straight  to  the 
pylorus.  The  membranes  are  extremely  deli- 
cate and  almost  transparent.  The  form  is  es- 
sentially similar  in  Chrysochloris  and  in  Con- 
dytura.  The  stomach  of  Tupaia,  according  to 
the  Baron  Cuvier,  is  of  a  globular  form. 

The  intestinal  canal  is  upon  the  whole  re- 
markably short  in  the  Insectivora.  There  are 
some  exceptions  to  this  rule,  but  the  only  one 
bearing  upon  a  difference  of  aliment  is  that  of 
the  hedgehog,  which,  as  has  been  before  ob- 
served, lives  partially  upon  vegetable  matters. 
In  this  animal  it  is,  with  regard  to  the  length 
of  the  body,  as  6.6  to  1 .  In  Talpa  and  Centenes 
this  proportion  is  even  exceeded,  but  it  is  com- 
pensated for  by  the  extreme  narrowness  of  the 
canal ;  the  diameter  of  which  is  to  its  length, 
in  the  mole,  as  1  to  82 ;  whilst  in  the  hedge- 
hog it  is  as  1  to  58.  In  Sorex  its  length  is  to 
its  diameter  only  as  about  3  to  1,  or  a  little 
more.  There  is  no  ccecum  known  to  exist  in 
any  of  the  Insectivora.  Cuvier  queries  whe- 
ther Tupaia  be  not  an  exception,  but  this  we 
have  at  present  no  means  of  ascertaining.  The 
liver  is  in  general  fully  developed  in  all  its 
parts ;  there  are  the  principal  lobe,  to  which 
the  gall-bladder  is  attached,  with  a  notch 
answering  to  the  suspensory  ligament,  a  right 
and  a  left  lobe,  and  two  smaller  lobes  or  lo- 
buli,  a  right  and  a  left.  The  whole  of  these 
parts  are  generally  found,  but  varying  without 
any  known  law,  or  any  ascertained  relation 
to  functional  peculiarity.  In  the  hedgehog 
and  in  the  mole  the  left  lobule  is  composed 
of  two  portions,  a  cardiac  and  a  pyloric,  as  in 
the  Rodentia.  In  Tupaia,  according  to  the  state- 
ment of  Cuvier,  the  three  portions  into  which 
the  liver  is  divided  belong  to  the  principal  lobe; 
there  is  no  right  or  left  lobe,  and  the  right  lo- 
bule is  also  wanting.  The  gall-bladder  is  for 
the  most  part  of  considerable  size.  In  the 
hedgehog  its  fundus  appears  beyond  the  free 
margin  of  the  liver,  and  is  supported  by  a 
process  of  falciform  ligament.  In  the  Tenrec, 
on  the  contrary,  it  is  as  it  were  incrusted  by 
the  substance  of  the  right  portion  of  the  prin- 
cipal lobe. 

IV.  Nervous  system. — The  form  and  propor- 
tions of  the  brain  in  some  of  the  Insectivora  ex- 
hibit a  degree  of  developement  not  materially 
superior  to  that  of  the  higher  Carnivora;  whilst 
others,  and  especially  the  mole,  have  the  same 
higher  proportion  which  are  found  in  the  Chei- 
roptera :  thus  in  the  hedgehog  the  volume  of 
the  brain  is  to  that  of  the  body  as  1  to  168 ; 
whilst  in  the  mole  it  is  as  1  to  36.  The  pro- 
portion of  the  cerebellum  to  the  cerebrum  in 
the  latter  animal,  however,  indicates  a  consi- 
derable developement  of  the  sexual  functions, 
being  as  1  to  4£.  Supposing  the  theories  of 
many  modern  physiologists  to  be  correct,  this 
fact  is  in  perfect  accordance  with  the  neces- 
sities of  the  animal,  whose  means  of  obtaining 
access  to  the  opposite  sex  are  extremely  diffi- 


INSECTIVORA. 


1003 


cult,  and  require  intense  ardour  and,  perseve- 
rance to  effect  this  object. 

The  most  remarkable  and  interesting  pecu- 
liarities which  are  to  be  met.  with  in  the  struc- 
ture of  any  of  the  Mammalia  are  to  be  found 
in  the  eye  of  the  mole,  and  doubtless  of  the 
nearly  allied  forms  of  Chrysochloris  and  the 
other  subterranean  species.  In  these,  in  order 
to  meet  the  requirements  of  their  habits,  the 
organ  of  sight  is  reduced  to  a  mere  rudiment, 
whilst  those  of  hearing  and  of  smell  are  deve- 
loped to  an  extraordinary  degree;  and  the 
theory  of  the  balance  of  organs  can  scarcely 
boast  of  a  stronger  support  in  the  whole  range 
of  animal  organization  than  in  this  instance. 

The  question  whether  the  mole  possesses  vi- 
sion has  been  long  and  often  debated.  With- 
out entering  into  an  unnecessary  examination 
of  all  that  has  been  said  on  both  sides  of  the 
question,  it  may  be  well  to  observe  that  the 
principal  argument  which  has  been  urged  on 
the  negative  is  derived  from  the  absence  of  an 
optic  nerve.  That  this  animal,  at  least  our 
common  species,  does  possess  the  faculty  of 
vision  to  a  certain  degree  cannot,  however,  be 
disproved,  whatever  may  be  the  means  by 
which  the  sense  is  communicated,  that  is  to 
say,  whatever  the  nerve  may  be  which  supplies 
the  place  of  the  true  optic  nerve ;  and  the  ex- 
periments of  Henri  le  Court  and  Geoffroi  St. 
Hilaire*  would  well  nigh  go  to  prove  the 
affirmative  of  the  proposition.  It  has  been 
urged  then  that  an  optic  nerve  is  absolutely 
necessary  to  the  existence  of  vision ;  and  that, 
therefore,  either  the  mole  has  a  true  optic  nerve, 
or  that  it  does  not  possess  vision.  There  have 
indeed  been  three  classes  of  observers  on  this 
point ;  those  who  maintain  that  the  mole  sees, 
and  that  it  possesses  an  optic  nerve  ;  those  who 
contend  that  it  is  blind,  and  possesses  no  such 
nerve  ;  and  others  have  ventured  to  agree  with 
the  former  as  to  its  power  of  vision,  and  with 
the  latter  in  denying  the  existence  of  the  optic 
nerve. 

The  eye  of  the  mole  is  extremely  small,  but 
differs  not  materially  in  its  structure  from  that 
of  other  animals.  The  pupil  is  elliptic  and 
vertical;  the  cornea  even  more  convex  than  that 
of  birds;  there  is  a  sclerotic  and  a  true  choroid. 
The  crystalline  lens  is  perfect,  and  much  more 
convex  than  in  most  of  the  Mammalia ;  and 
the  eye-ball,  emptied  of  its  contents,  exhibits 
at  the  base  a  lining  of  a  whitish  colour.  "  In 
an  injected  subject,"  says  Geoffroi,  "  the  cen- 
tral artery  of  the  retina  was  distinctly  seen." 
Whether  there  be  or  not  a  true  retina  will  be 
variously  solved  according  to  the  views  of  dif- 
ferent physiologists.  If  the  nerve,  whatever  it 
may  be,  which  takes  here  the  place  of  the 
optic  nerve,  be  really  the  seat  of  the  sense  of 
vision,  there  seems  to  be  no  objection  to  con- 
sider its  expansion,  upon  which  the  pictures  of 
objects  are  impressed,  as  a  retina ;  giving  the 
name  rather  to  the  physiological  than  to  the 
anatomical  character  of  the  part ;  but  be  this 
as  it  may,  from  the  posterior  part  of  this  minute 

*  Geoff.  St.  Hilaire,  C'ours  d'Hist.  Nat.  des  Mam. 
lev.  16. 


eye  there  passes  a  distinct  branch  of  a  nerve. 
Perhaps,  after  all,  the  name  and  analogy  of 
this  nerve  will  be  viewed  differently  according 
to  the  general  views  of  organic  developement 
entertained  by  different  physiologists.  Geoffroy 
considers  it  as  the  optic  nerve,  notwithstanding 
it  has  no  connexion  with  that  part  of  the  brain 
which  in  all  other  cases  is  in  immediate  com- 
munication with  it;  and  he  founds  this  opinion 
upon  the  theory  that  all  organs  are  developed 
from  without.  His  words  are  as  follow:  — 
"  Qu'est  ce  que  ce  nerf  ?  La  monstruosite  et 
la  nouvelle  theorie  sur  le  point  de  depart  des 
developpemens  organiques  assure  ma  marche : 
appuye  sur  ces  deux  fanaux,  aujourd'hui  heu- 
reusement  importes  dans  l'histoire  encore  si 
obscure  des  premieres  formations  je  ne  doute 
pas  que  ce  ne  soit  le  nerf  optique.  C'est  ce 
nerf,  parceque  cet  appareil,  qui  est  au  complet 
comme  globe  oculaire,  a  du  se  former  de  toutes 
ses  dependances  jusqu'a  l'empechement  qui  en 
arrete  le  cours.  Cette  determination  ne  sauroit 
etre  douteuse  pour  qui  reconnait  que  les  or- 
ganes  naissent  a  la  circonference  de  I'etre,  d'ou 
ils  envoient  leurs  rameaux  s'embrancher  au  plus 
pres  dans  le  centre.* 

Amongst  those  who  assert  that  the  mole  pos- 
sesses a  true  optic  nerve  is  Miiller.  His  state- 
ment is  so  brief,  and,  it  may  be  said,  so  unsa- 
tisfactory, that  it  can  scarcely  be  considered  as 
sufficient  to  outweigh  the  carefully  formed  opi- 
nion of  many  who  differ  from  him.  His  state- 
ment, as  given  in  Dr.  Baly's  translation  of  his 
admirable  book,  is  as  follows: — "  Some  ani- 
mals, though  provided  with  eyes — for  instance, 
the  mole  and  the  proteus  anguinus — have  been 
said  to  want  the  optic  nerves;  the  sense  of 
vision  being  then  placed  in  the  ophthalmic 
branch  of  the  fifth  nerve.  This  statement  has 
arisen,  in  the  case  of  the  mole,  from  inaccuracy 
in  the  anatomical  examination;  and  the  same 
is  the  case  probably  in  the  Proteus.  The  mole 
has  an  uncommonly  small  optic  nerve,  as  Dr. 
Henle  has  shewn  me."f  On  the  other  hand, 
Serres,  Gall,  Desmoulins,  and  others  have 
agreed  in  delating  that  there  is  no  nerve  passing- 
from  the  optic  lobes  to  the  eye  ;  and  Dr.  Todd 
has  recently  verified  this  statement,  and  traced 
the  nerve  which  does  supply  this  organ,  which 
he  finds  to  be  the  ophthalmic  branch  of  the 
fifth  pair.  I  give  an  enlarged  view  of  a  dissec- 
tion of  this  nerve,  drawn  by  Mr.  Bowman. 
( Fig.  453.) 

a  is  the  fifth  nerve  within  the  cranium,  b 
the  Gasserian  ganglion,  c  the  inferior  maxillary 
nerve,  d  the  ophthalmic  nerve  going  to  the  eye 
(e,)  f  the  superior  maxillary  nerve,  g  branch  of 
the  ophthalmic,  supplying  the  side  of  the  nose. 
Dr.  Todd  in  a  letter  to  me  says,  "  I  have 
been  lately  looking  at  the  point  about  the  optic 
nerve  in  the  mole.  I  can  see  an  optic  commis- 
sure, but  no  optic  nerve  beyond  it,  and  I  can 
very  distinctly  trace  a  branch  [the  ophthalmic] 
of  the  fifth  to  the  eye.  I  carefully  searched  to 
see  if  a  second  nerve  were  bound  up  in  the 
cellular  sheath  with  it,  but  could  find  none. 

*  Cours  d'Hist.  Nat.  des  Mammif.  16  If  9.  p.  27. 
t  Miiller's  Phys.  by  Baly,  p.  767. 


1004 


INSECTIVORA. 


The  chiasma  is  very  distinct,  without  a  trace  of 
a  nerve  proceeding  from  it." 


Fig.  453. 


The  organ  of  hearing  in  the  mole  is  so  con- 
structed as  to  afford  the  greatest  possible  deli- 
cacy and  acuteness  of  this  important  sense,  and 
thus  to  counterbalance  the  deficiency  in  that  of 
sight.  It  would  indeed  appear  that  the  mass 
of  compact  bone  constituting  the  petrous  por- 
tion of  the  temporal,  which  surrounds  the  laby- 
rinth in  most  of  the  Mammalia,  must  more  or 
less  diminish  the  powers  of  hearing,  for  we  find 
it  deficient  in  many  animals,  which  from  their 
habits  require  this  sense  to  be  in  the  greatest 
perfection.  Thus,  in  the  mole,  the  semicircular 
canals  are  free  and  visible  within  the  cranium, 
without  any  preparation ;  and  the  parietes  of 
the  cochlea  itself  are  almost  as  cellular  and 
loose  as  we  find  in  birds. 

The  ear  of  the  mole  possesses  no  concha ;  it 
is  small  in  the  shrews;  and  in  the  water-shrews 
(Hydfosorex )  the  external  meatus  is  closed  at 
the  will  of  the  animal  by  means  of  the  anti- 
tragus;  a  provision  obviously  essential  to  its 
aquatic  habits. 

When  it  is  considered  that  the  sense  of 
vision  is  only  available  on  the  rare  occasions 
of  the  appearance  of  the  mole  on  the  surface, 
and  then  only  for  very  limited  objects,  and  that 
all  its  intimations  of  danger,  and  its  only  guide 
to  the  opposite  sex,  are  by  means  of  the  sense  of 
hearing,  the  necessity  for  this  extraordinary  deve- 
lopement  of  that  sense  at  the  expense  of  that  of 
sight  becomes  obvious.  And  as,  from  the  nature 
and  situation  of  its  food  and  its  means  of  pro- 
curing it,  the  sense  of  smell  is  equally  neces- 
sary for  effecting  this  object,  we  find  that  the 
olfactory  organ  is  also  of  considerable  volume. 
The  structure  of  the  nose  itself  is  highly  curious 
and  admirably  suited  to  the  habits  of  the  ani- 


mal. The  cartilages  of  the  nose  are  elongated 
into  a  tube  or  trunk,  which  extends  far  beyond 
the  osseous  basis,  and  is  supported  by  a  very 
delicate  moveable  bone,  which  is  represented 
in  the  figure  of  the  cranium  of  the  mole  at 
jig.  441.  It  is  furnished  with  a  muscular  appa- 
ratus of  considerable  complexity  (seefg.  446), 
consisting  of  no  less  than  four  pairs  of  muscles, 
which  arise  from  above  the  ears,  and  passing 
forwards  are  inserted  by  separate  tendons  into 
the  circumference  of  the  extremity  of  the  carti- 
laginous snout.  This  structure  is  of  the  utmost 
advantage  to  the  animal  in  its  subterranean 
search  after  worms  and  insects. 

There  is  no  order  of  Mammalia  in  which  a 
greater  contrast  is  exhibited  in  the  external 
covering  of  the  body  than  in  the  different 
groups  of  thp  Insectivora.  The  porcupine 
and  the  mouse,  amongst  the  Rudentia,  do  not 
offer  a  more  remarkable  contrast  in  this  respect 
than  do  the  two  families  of  the  Erinaceada  and 
the  Talpida.  The  habits  of  the  hedgehog  de- 
pending for  its  defence  upon  the  panoply  of 
armour  which  it  presents  to  its  enemies,  when 
rolled  up  in  a  compact  ball  by  the  muscular 
apparatus  already  described,  it  is  furnished  on 
all  the  upper  and  lateral  parts  of  the  body 
with  hard  sharp  spines  or  quills.    Fig.  454 

Fig.  454. 


is  taken  from  a  drawing  by  William  Bell, 
engraved  in  the  Hunterian  Catalogue,  vol.  iii. 
from  which  also  the  following  description  is 
borrowed: — "  On  the  cut  edge  of  the  skin 
may  be  seen  the  roots  and  sockets  of  the  quills, 
extending  to  different  depths  from  the  surface, 
according  to  the  period  of  their  growth :  the 
newly  formed  ones  are  lodged  deep  and  ter- 
minate in  a  broad  basis,  the  pulp  being  large 
and  active,  and  the  cavity  containing  it  of  cor- 
responding size;  but  as  the  growth  of  the  quill 
proceeds,  the  reflected  integument  forming  the 
socket  contracts,  and  gradually  draws  the  quill 
nearer  the  surface;  the  pulp  is  at  the  same  time 
progressively  absorbed,  and  the  base  of  the 


INSECTIVORA. 


1005 


quill  in  consequence  gradually  increases  in  size, 
so  that  it  is  at  last  seen  to  be  attached  to  the 
surface  of  the  skin  by  a  very  narrow  neck, 
below  which  the  remains  of  the  socket  and 
theca  are  seen  in  the  form  of  a  small  bulb." 
(  Vig.  454,  a.)  "  A  completely  formed  prickle  or 
quill  cut  longitudinally  and  magnified,  shewing 
that  it  is  hollow  and  filled  with  a  pithy  sub- 
stance, which  is  transversely  disposed,  so  as  to 
divide  the  cavity  into  many  sections."  But  the 
defence  of  the  animal  against  attack  is  not  the 
only  object  of  this  modification  of  the  hair. 
I  have  more  than  once  seen  a  hedgehog  run  to 
the  edge  of  a  precipitous  descent,  and  without 
a  moment's  hesitation  throw  itself  over,  rolling 
itself  up  at  the  same  instant,  and  on  reaching 
the  bottom  run  off  perfectly  uninjured.  It  is 
unnecessary  to  point  out  how  perfectly  this 
habit  is  provided  for  by  the  elasticity  of  the 
spines,  dependent  upon  their  structure,  as  ex- 
hibited in  the  figure.  The  under  parts  of  the 
body  and  the  limbs  are  covered  with  ordinary 
hair.  The  Tenrec  and  other  Erinaceada:  re- 
semble the  hedgehog  in  these  respects,  and 
in  some  species  the  quills  and  hair  are  inter- 
mixed. 

The  mole,  on  the  other  hand,  possesses  hair 
•of  the  softest  and  most  flexible  description. 
In  its  subterranean  galleries,  which  are  not 
large  enough  to  allow  it  to  turn  round,  it  must 
often  be  obliged  to  retreat  backwards ;  and  the 
hair  therefore  is  so  constructed  as  to  lie  equally 
smooth  in  every  direction.  This  has  been  sup- 
posed to  be  effected  merely  by  its  growing  ex- 
actly perpendicular  to  the  surface  of  the  body  ; 
but  it  is  in  fact  still  more  effectually  provided 
for  by  a  remarkable  form  of  the  hair  itself. 
Each  hair  consists  of  three  or  four  broader 
portions  connected  by  intervening  portions  of 
extreme  tenuity;  so  that  there  are  several 
points  in  the  length  of  each  hair  which  pre- 
sent no  appreciable  resistance.  The  hair 
of  the  shrews  is  similarly  constructed,  and  in 
each  case  it  is  to  this  structure  that  the  pecu- 
liar and  beautiful  softness  which  characterizes 
it  is  owing.  It  is  worthy  of  remark  that  the 
colouring  matter  of  the  hair  exists  only  in  the 
broader  portions,  the  intermediate  parts  being 
wholly  colourless. 

V.  Organs  of  reproduction.  —  The  repro- 
ductive organs  of  the  Insectivora  offer,  in 
several  instances,  some  remarkable  peculiari- 
ties. The  subterranean  life  of  many  of  these 
animals  renders  the  meeting  of  the  sexes  in 
their  natural  haunts  a  matter  of  almost  for- 
tuitous occurrence  ;  and  it  is  therefore  neces- 
sary that  the  sexual  desire  should  in  the  male 
be  sufficiently  powerful  to  force  him  as  it  were 
to  seek  and  pursue  the  other  sex  through  all 
the  difficulties  and  disadvantages  occasioned 
by  their  peculiar  habits.  Hence  we  find  that 
in  most  of  them  the  male  organs  are  developed 
to  an  extraordinary  degree ;  and  in  the  mole 
the  enlargement  of  the  testes  as  the  season  of 
pairing  advances  is  as  remarkable  as  it  is  in  the 
sparrow  or  in  any  other  example  of  this  sea- 
sonal increase  of  those  organs.  Two  incom- 
patible statements  have  been  made  respecting 
s.lie  testes  in  the  mole.    Cuvier  asserts  that 


they  make  their  appearance  externally  during 
the  season  of  propagation.  Blumenbach  de- 
clares that  they  belong  to  the  true  testiconda, 
with  the  hedgehog,  &c.  The  truth  is,  as  de- 
monstrated with  his  usual  ingenuity  by  Geof- 
roy  St.  Hilaire,  that  the  testicles  of  the  mole 
never  make  their  appearance  externally,  al- 
though during  the  season  of  their  greatest  de- 
velopement  they  would  do  so  but  for  the 
peculiar  construction  of  the  parts  in  which  the 
organs  of  generation  in  this  animal  are  con- 
tained ;  for  the  abdominal  cavity  extends  be- 
yond the  pelvis,  as  far  as  the  first  four  coccy- 
geal vertebra,  which  in  fact  do  not,  properly 
speaking,  in  any  degree  constitute  the  tail, 
which  is  formed  only  of  the  posterior  seven 
vertebra,  and  the  testes  during  the  season  are 
protruded  so  as  to  lie  concealed  under  this 
portion  of  the  caudal  division  of  the  spine, 
which  forms  as  it  were  a  continuation  of  the 
upper  part  of  the  pelvis.  In  the  hedgehog  the 
testes  remain  within  the  abdomen  excepting 
during  the  spring,  and  even  then  they  are  but 
little  protruded.  The  object  of  their  being 
thus  generally  protected  is  obvious :  in  the 
hedgehog  these  organs,  if  external,  would  be 
exposed  to  danger  from  the  act  of  rolling  itself 
up,  and  in  the  mole  and  its  congeners  they 
would  interfere  with  the  act  of  excavating 
their  subterranean  passages.  The  penis  in  the 
mole  possesses  a  remarkable  peculiarity,  which 
doubtless  has  reference  to  the  condition  of  the 
female  organ  presently  to  be  described.  It 
consists  in  a  small  terminal  bony  appendage, 
covered  but  slightly  by  integument;  it  was 
considered  by  Daubenton  as  the  os  penis,  but 
from  its  different  situation  it  may  be  doubtful 
perhaps  if  it  be  in  truth  analogous  to  that  part. 

The  male  organs  are  in  the  hedgehog  deve- 
loped to  an  extraordinary  degree,  more  espe- 
cially the  vesicula  seminales.  The  testes  are  of 
an  oval  form,  smooth,  and  although  large  in 
proportion  to  the  size  of  the  animal,  are  much 
smaller  than  the  vesiculae  seminales  ;  these  are 
of  enormous  size,  each  consisting  of  four  or 
five  fascicles  of  extremely  convoluted  tubes, 
the  membranous  parietes  of  which  are  ex- 
tremely thin  and  fragile.  Cowper's  glands  and 
the  prostatic  gland  are  also  of  considerable  size 
in  this  animal.  The  orifices  of  the  vasa  defe- 
rentia,  vesicula  seminales,  prostatic  gland,  and 
Cowper's  glands  all  open  within  the  foramen 
caecum  of  the  urethra. 

The  female  organs  in  the  mole  offer  some 
peculiarities  which  deserve  more  attention  than 
they  have  hitherto  received. 

In  the  first  place,  it  appears  that  in  this 
animal   the   urinary  and  genital  orifices  are 

Fig.  455. 


i  2 


1006 


INSECTIVORA. 


wholly  distinct.  The  clitoris,  (Jig.  455,  c,) 
which  is  of  considerable  length,  and  very  much 
resembles  the  penis  of  the  male,  is  pierced  for 
the  passage  of  the  urine,  and  thus  constitutes 
a  true  urinary  penis.  Beyond  this  is  a  trans- 
verse slit  of  a  slightly  crescentic  form,  (Jig. 
455,  2),  which  constitutes  the  opening  of  the 
vagina.  There  are  none  of  those  duplicatures 
of  the  integument  which  in  other  Mammalia 
constitute  the  labia  and  nymphce,  but  the  skin 
is  smooth.  But  one  of  the  most  curious 
points  in  the  structure  of  these  parts  is  that 
in  the  virgin  state  this  vaginal  aperture  does 
not  exist,  (Jig.  455,  1,)  the  skin  being  per- 
fectly and  tightly  drawn  over  the  entrance ;  so 
that  there  are  in  this  state  but  two  openings,  the 
urethral  and  the  intestinal.  So  perfectly  is  this 
the  case  that  it  is  very  difficult  to  know  a  virgin 
female  mole  from  the  male  by  mere  external 


examination.  As  this  covering  is  so  tense,  the 
utility  of  the  little  bone  at  the  extremity  of  the 
penis  in  the  male  is  very  obvious,  and  its 
pointed  and  tapering  form  is  at  once  accounted 
for  :  it  is  clearly  intended  to  perforate  this  tense 
covering  to  the  vagina. 

Another  peculiarity  in  this  animal  is  that  the 
abdominal  cavity  being  extended  greatly  be- 
yond the  pelvis,  the  vagina,  the  rectum,  and 
the  urinary  passage  terminate  considerably  fur- 
ther back  than  in  other  animals.  The  opening 
of  the  rectum  is  opposite  to  the  articulation  of 
the  fourth  with  the  fifth  caudal  vertebra. 

The  uterus  is  of  considerable  size  in  the  mole, 
and  its  cornua  much  convoluted. 

For  Bibliography,  see  that  of  Mammalia. 

(T.  Bell.) 


ANALYTICAL  INDEX 

TO  THE 

SECOND  VOLUME. 


DIAPHRAGM  (in  anatomy  generally),  1 
Diaphragm  (in  human  anatomy),  1 

costal,  upper,  true  or  greater  muscle,  2 
septum  transversum,  2 
centrum  tendineum,  cordiform  tentfon,  2 
ligamentum  arcuatum — 

externum,  3 
internum,  S 

vertebral  or  smaller  muscle,  crura  pillars  or  appen- 
dices, 3 
foramina  or  openings,  3 

foramen  quadratum  s.  vennsum,  3 
elipticum  s.  oesopliageum,  3 
aorticum,  3 

other  smaller  foramina,  4 
relations  to  the  pleura;,  peritonaeum,  &c.  4 
arteries,  4 
veins,  4 
lymphatics,  4 
nerves,  4 
uses,  4 

malformations  and  diseases,  6 
absence,  6 
openings,  6 
ulcers,  6 
wounds,  6 
rupture,  6 
inflammation,  6 

gangrene,  collections  of  pus,  tumours,  &c.  6 
cartilaginous  and  osseous  deposits,  6 
displacement  from  ascites,  &c.  6 
Digestion,  6 

I.  Description  of  the  organs  of  digestion,  7 

mouth  with  its  appendages,  the  lips,  &c.  8 
teeth,  8 

saliv-iry  glands,  8 
oesophagus  and  deglutition,  8 

stomach,  9 
intestinal  canal,  10 

peculiarities  of  the  digestive  organs  in  different 
classes,  11 

II.  An  account  of  the  nature  of  the  substances  usually 

employed  as  food,  12 
animal  compounds,  13 
vegetable  substances,  13 
liquids,  14 
condiments,  15 
medicaments,  15 

III.  An  account  of  the  changes  which  the  food  ex- 

periences in  the  process  of  digestion,  15 
chymification,  16 

physical  and  chemical  properties  of  the  gastric 

juice,  17 
chylirication,  19 

analysis  of  chyle,  19 

IV.  Theory  of  digestion,  21 

V.  Peculiar  affections  of  the  digestive  organs,  25 
Digestive  canal  (comparative  anatomy),  27 

I.  Polygastrica,  28 
Echinodermata,  30 

systematic  arrangement,  30 

I,  Tegumentary  system,  31 

in  the  Asterias,  31 
in  the  Echini,  32 
in  the  Holothuriae,  33 

II.  Organs  of  motion,  34 
in  Asterias,  34 


Echinodermata  (continued), 
in  Echini,  35 
in  HolothuriEe,  36 

III.  Digestive  organs,  36 
in  Asterias,  36 

in  Echini,  38 

in  Holothuriae,  39 

IV.  Respiratory  organs,  40 
in  Asterias,  40 

in  the  Echini,  41 
in  Holothurice,  41 

V.  Vascular  system,  41 
in  the  Asterias,  41 
in  the  Echini,  43 

in  the  Holothuriae,  43 

VI.  Nervous  system,  44 

VII.  Generative  organs,  44 
in  the  Asterias,  45 

in  the  Echini,  45 
in  Holothuriae,  45 

VIII.  Regeneration  of  lost  parte,  45 
Edentata,  46 

osseous  system,  48 
skull,  48 

vertebral  column,  49 
pelvis,  50 

anterior  extremity,  50 
posterior  extremity,  50 
of  the  Edentata  proper,  51 
digestive  organs,  53 
organs  of  circulation,  54 
tegumentary  system,  54 
Elasticity,  55 

general  remarks,  laws,  &c.  56 

tissues  of  the  body  in  the  order  of  their  elasticity,  58 
yellow  fibrous  tissue,  58 
cartilage,  58 
fibro-cartilage,  58 
skin,  59 

cellular  tissue,  59 
muscle,  59 
bone,  59 

mucous  membrane,  59 
serous  membrane,  60 
nervous  matter,  60 
fibrous  membrane,  60 

instances  in  which  elasticity  plays  an  important  part 
in  the  mechanism  of  organized  beings,  60 
in  the  protection  of  the  body  and  its  parts,  60 
as  a  substitute  for  muscular  contraction,  61 
as  preserving  the  patulous  condition  of  certain 
outlets,  61 

as  subservient  to  locomotion,  or  movement  gene- 
rally, 61 

as  a  means  of  dividing  or  transferring  muscular 
force,  62 

converting  occasional  into  conti- 
nued forces,  62 
Elbow,  fold  or  bend  of  the  arm,  62 
skin  and  subcutaneous  tissue,  63 
veins,  63 
nerves,  64 
aponeurosis,  64 
brachial  artery,  64 
development,  64 
varieties,  65 

selection  of  a  vein  for  phlebotomy,  65 


1008 


ANALYTICAL  INDEX. 


Elbow,  articulation  of  the,  65 
bones,  65 
ligaments,  66 
motions,  67 
lateral  motion,  67 
Elbow-joint,  abnormal  conditions  of  the,  67 
I.  Accidents,  68 

simple  fractures,  68 

of  the  humerus  and  its  condyles,  68 
of  the  ulna,  69 
of  the  olecranon,  69 

luxations,  69 

of  both  bones  of  the  fore-arm  back- 
wards, 69 

of  the  bones  of  the  fore-arm  laterally,  71 
backwards 

and  outwards,  72 

backwards 

and  inwards,  72 

of  the  ulna  alone  directly  backwards,  72 
upper  extremity  of  the  radius 
from  the  humerus  and  ulna,  72 

of  the  radius  forwards,  73 

radius  alone  laterally,  73 
radius  alone  backwards,  74 
subluxation  of  die  upper  extremity  of  the  radius 
with  elongation  of  the  coronary  ligament,  74 
congenital  or  original,  of  the  upper  head  of  the 
radius  backward,  75 
U.  Diseases,  77 

of  the  synovial  membrane,  synovitis,  77 
of  the  cartilages — inflammation,  softening,  ab- 
sorption, 77 
of  the  bones — caries,  elastic  white  swelling,  78 
rheumatism,  79 
Electricity,  animal,  81 
electrical  fishes,  81 

circumstances  under  which  discharges  from  electrical 

fishes  take  place,  82 
motions  of  the  fish  in  the  act  of  discharging,  83 
physiological  effects  of  the  discharge,  83 
magnetical  effects  of  the  discharge,  85 
chemical  effects  of  the  discharge,  86 
results  of  experiments  on  the  transmission  of  the  dis- 
charge through  various  conducting  bodies,  86 
production  of  a  spark  and  evolution  of  heat,  87 
anatomy  of  the  electrical  organs,  87 
in  the  torpedo,  S8 
in  the  gymnotus,  91 
in  the  silurus,  53 
analogies  of  animal  electricity,  93 
manifestations  of  common  electricity  in  animal  sub- 
stances and  in  living  animals,  95 
uses  of  animal  electricity,  97 
Encephalon,  98 
Endosmosis,  98 

measurement  of  the  amount  of  endosmosis,  98 
strength  of  endosmosis,  98 
effects  of  temperature,  100 
explanation  of  the  phenomena,  100 
circumstances  in  which  endosmosis  occurs,  110 
Entozoa,  111 

definition,  111 

primary  division  into  three  classes— Protelmintha, 

Sterelmintha,  and  t'oelelmintha,  111 
families  of  the  first  class,  Protelmintha: 

Cercariadae,  )  1 1 

Spermatozoa,  111 

Vibrionidae,  113 

Trichina  spiralis,  1 13 
families  of  the  second  class,  Sterelmintha,  equivalent 
to  the  Orders  ot  Rudolphi,  115 

Cystica,  115 

Cestoidea,  116 

Tremaloda,  1 16 

Acanthocephala,  1 16 
families  of  the  third  class,  Ccelelmintha,  116 

Nematoidea,  116 

Acanthotheca,  116 
description  of  species  of  human  entozoa  belonging  to 
the  above  Orders,  117 

Acephalocystis  endogena,  Pill-box  Hydatid,  1 17 

Echinococcus  hominis,  117 

Cysticercus  cellulosa,  118 

Bothriocephalus  latus,  120 

Taenia  solium,  120 

Distoma  hepaticuin,  121 

Polystoma  pinguicola,  121 
venarum,  121 

Diplostomum  volvens,  121 

Filiaria  Medinensis,  122 

oculi  humani,  122 
bronchialis,  122 

Trichocephalus  dispar,  122 

Spiroptera  hominis,  123 

Strongylus  gigas,  125 

Ascaris  lumbricoides,  125 
vermicularis,  125 
tabular  view  of  Entozoa  hominis,  126 
anatomy  of  the  Entozoa,  126 

tegumentary  system,  126 

epidermic  processes  or  spines,  127  * 

A".  C.  Sk.:A« 


Entozoa  (continual). 

muscular  sy6tem,  127 

nervous  system,  129 

digestive  organs,  131 

respiratory  organs,  136 

excretory  glands,  136 

organs  of  generation,  137 
Erectile  tissue,  144 
Excretion,  147 

I.  Necessity  of  excretion,  148 

II.  Products  to  be  held  excretions,  149 
excretions  from  the  lungs,  149 

skin,  149 
bowels,  149 
kidneys — urine,  149 
excrementitious  and  recrementitious  secretions, 
150 

III.  Effects  of  the  suppression  of  secretions  on  the 

animal  economy,  150 

IV.  Manner  in  which  excretions  are  effected,  150 

V.  Matters  of  excretion  are  separated  from  the  blood 

rather  than  formed  at  the  parts  where  they  ap- 
pear, 151 

VI.  Original  source  of  the  matters  thrown  out  by  ex- 

cretion, 152 
Extremity  (in  human  anatomy),  154 
superior  extremity,  154 
clavicle,  154 

structure,  156 

development,  156 
scapula,  156 

structure,  159 

development,  159 
humerus,  159 

structure,  161 

development,  161 
fore-arm : 
ulna,  162 

structure,  163 
radius,  163 

structure,  164 

development  of  radius  and  ulna,  164 
hand,  165 
inferior  extremity,  165 
femur,  165 

structure,  167 

development,  167 
patella,  168 

structure  and  development,  168 

leg: 

tibia,  168 

structure,  170 
fibula,  170 

structure,  171 

development  of  the  bones  of  the  leg,  171 
abnormal  conditions  of  the  bones  of  the  extremi- 
ties, 171 

Eye: 

general  view,  171 
sclerotic  coat  or  membrane,  174 
cotnea,  175 
■choroid  coat,  178 
tapetum,  179 

orbiculus  s.  circulus  ciliaris,  ciliary  circle,  180 

corpus  ciliare,  ciliary  processes,  180 

pigmentum  nigrum,  180 
iris,  182 

membrana  pupillaris,  184 
retina,  185 

lamina  cribosa,  185 

porus  opticus,  186 

layers  or  membranes,  186 

foramen  centrale, orforamen  of  Soemmerring,  188 
vitreous  humour,  19! 
canal  of  Petit,  192 
corona  ciliaris,  193 
crystalline  lens,  194 

capsule,  199 
aqueous  humour,  201 
peclen  s.  marsupium  nigrum,  203 
choroid  gland  or  muscle,  205 
Face  (in  anatomy  generally  and  in  human  anatomy),  207 
I.  Bones  of  the  face,  207 

superior  maxillary  bones,  207 

maxillary  sinus,  209 
connexions  of  the  maxillary  bone,  209 
structure,  209 
development,  209 
ossa  intermaxillaria,  210 
palate  bones,  210 
connexions,  211 
structure  and  development,  211 
malar  bones,  211 
connexions,  211 
structure  and  development,  212 
nasal  bones,  212 
connexions,  212 
structure  and  development,  212 
lachrymal  bones,  212 
mnexions,  212 
.[^structure  and  development,  212 
fnfeffej^turbinated  or  spongy  bones,  21J 


,.4  ■■  h 


ANALYTICAL  INDEX. 


1009 


Face  (continued). 

connexions,  <2\$ 
structure  and  development,  213 
vomer,  ^13 

connexions,  213 

structure  and  development,  213 
lower  jaw  bone,  213 

structure,  215 

connexions  and  uses,  215 

development,  215 
of  the  face  in  general.    Dimensions,  215 

mechanism  of  the  face,  217 

development  of  the  face,  218 

articulations  of  the  face,  219 

abnormal  conditions  of  the  bones  of  the  face, 
219 

II.  Muscles  of  the  face,  220 
orbicularis  palpebrarum,  221 

relations,  221 

action,  221 
corrugatoi  supercilii,  222 
levator  palpebral  superioris,  222 

relations  and  action,  222 
muscles  of  the  nasal  region  : 
pyramidalis,  222 

levator  labii  superioris  alaeque  nasi,  222 

relations  and  action,  222 
triangularis  nasi,  223 

relations  and  action,  223 
depressor  ala  nasi  (myrtiformis),  223 

relations,  223 
dilator  alee  nasi,  223 
muscles  of  the  labial  region; 
oibicularis,  223 

relations,  223 

actions,  224 
naso-labialis,  224 
levator  labii  superioris,  224 

relations  and  action,  224 
zygomalicus  minor,  224 

relations  and  action,  224 
zygomaticus  major,  224 

relations  and  action,  224 
levator  anguli  oris,  224 

relations  and  action,  224 
depressor  anguli  oris  (triangularis  oris),  225 

relations,  action,  225 
depressor  labii  inferioris  (quadrants  menti),  225 

relations  and  action,  225 
levator  menti  (houppe  du  menton),  225 

action,  225 
buccinator,  225 

relations  and  action,  220 
platysma  myoides,  2^6 

general  review  of  the  muscles  of  the  face,  227 

III.  Integuments  of  the  face,  227 

IV.  Vessels  of  the  face,  227 
V.  Nerves  of  the  face,  228 

VI.  Abnormal  conditions  of  the  soft  parts  of  the  face, 
228 
Fascia,  229 

1.  Cellular  fasciae,  229 

2.  Aponeuroses,  or  aponeurotic  fascise,  231 
Fat,  031 

varieties  of  fat : 

lard,  232 

human  fat,  232 

fat  of  beef,  233 

neat's  foot  oil,  233 

goat's  fat,  233 

mutton  fat,  233 

whale  or  train  oil,  233 

spermaceti  oil,  233 

phocenine,  234 

fat  of  birds,  234 

fat  of  insects,  235 

adipocere,  235 
Femoral  urtery,  235 

course  and  relations  generally,  235 

femoral  canal  and  femoral  sheath,  237 

particular  course  and  relations,  237 
in  its  superior  portion,  237 
in  its  second  or  middle  portion,  242 
in  its  inferior  portion,  242 

varieties,  243 

branches  of  the  femoral  artery,  243 
superficial  epigastric,  243 

external  pndic,  244 
anterior  iliac,  244 
profunda  femoris,  245 

branches  of  the  profunda,  246 
external  circumflex,  246 
internal  circumflex,  247 
first  perforating  artery,  248 
second  peiforating  artery,  248 
third  perforating  artery,  248 
termination  of  the  profunda,  249 
anastomoiica  magna,  or  superficial  supe- 
rior internal  articular,  249 

other  branches,  and  considerations  on  the 
collateral  circulation  of  the  thigh,  249 


Fevwrul  artery  (continued) . 

anastomoses  of  the  branches  of  the  femoral  ar- 
tery, 250 

effects  of  obstructions  at  different  points  in  the 

course  of  the  artery,  251 
operative  relations  of  the  femoral  artery,  252 

Fibrine,  257 
Fibro-cartHage,  260 

morbid  conditions  of,  262 
Fibrous  tissue,  263 

white  fibrous  organs,  263 

yellow  elastic  fihrous  organs,  263 

I.  White  fibrous  organs,  263 

bloodvessels,  263 
absorbents,  263 
nerves,  263 

chemical  properties,  263 
physical  properties,  263 
periosteum,  264 
fascia?,  264 

tendinous  sheaths,  264 
fibrous  coverings,  264 
ligaments,  264 
tendons,  265 

II.  Yellow  elastic  fibrous  organs  (tela  elastica),  265 
organization  and  properties,  265 

morbid  anatomy  of  the  fibrous  tissues  : 
inflammation,  266 

cartildginous  transformation  and  ossification, 
966 

fungus,  266 
osteo-sarcoma,  Q67 
Fibular  artery,  (arteria  peroncea,)  267 
branches : 

anterior  peionceal,  257 
posterior  peronceal,  267 
Fifth  pair  of  nerves,  trigeminal  or  trifacial  nerve,  268 
general  structure  and  encephalic  connexions,  268 
external  or  extracephalic  portion  of  the  nerve,  278 
first  or  ophthalmic  division,  279 
its  branches  : 

recurrent  branch  of  the  first  division,  279 
frontal  nerve,  279 
nasal  nerve,  281 
lachrymal,  282 
second  division  of  the  fifth  or  superior  maxillary 

nerve,  283 
its  branches : 

temporo-malar,  284 
spheno-palaline,  284 

spheno-palaiine  ganglion,  or  ganglion  of  Meckel, 

285 

posterior-superior  dental,  289 
anterior-superior  dental,  289 
facial  branches,  289 
third  division  of  the  filth  or  inferior  maxillary  nerve,2QO 
its  branches : 

the  masseteric,  201 
the  deep  temporals,  291 
the  buccal,  291 
the  pterygoid,  291 

otic,  or  auricular  ganglion  of  Arnold,  292 
the  superficial  temporals,  293 
the  inlerior  maxillary  or  dental,  294 
the  lingual,  295 

chorda  tympani,  295 
submaxillary  ganglion,  297 
ganglion  of  the  lift h  nerve,  ganglion  semilunare  Gas- 
serii,  298 

vital  properties  of  the  fifth  pair  of  nerves,  299 
sensibility,  299 

influence  upon  sensation  and  volition,  29£> 

Bell's  experiments,  299 

Magendie's  experiments,  300 

Mayo's  experiments,  300 
relation  to  the  special  senses,  305 

smell,  305 

vision,  307 

hearing,  309 

influence  upon  the  nutrition  of  the  parts  to  whicfi 
it  is  distributed,  309 
progression,  315 
influence  of  disease  on  the  functions  of  the  nerve, 

316 

Fatus  (normal  anatomy),  sub  voce  Ovum 
Feetus  (abnormal  anatomy),  316 

atrophy,  318 

hernia?,  319 

hernia  cerebri,  encephaloccle,  320 
spina  bifida,  321 
cranial  tumours,  323 
injuries  of  the  cranial  bones,  323 
fractures  of  the  long  bones,  324 
mutilations,  separation  of  parts  already  formed, 
324 

convulsive  affections,  329 
effects  of  mental  impressions  on  the  mother,  330 
effects  of  inflammation,  organic  lesions,  &c.  330 
in  the  stomach  and  bowels,  331 
liver,  331 
lungs,  331 

3  u 


1010 


ANALYTICAL  INDEX. 


Fcetus  (continued), 

pleuritis,  332 

purulent  effusions,  33'2 

dropsical  effusions,  33*2 

induration  of  the  cellular  tissue,  332 

cutaneous  affections,  333 

affections  of  the  heart  and  pericardium,  334 

pericarditis,  334 

thymus,  334 

thyroid  gland,  S35 

abnormal  conditions  of  the  fcetal  bladder,  335 

urinary  deposits,  336 

premature  development  of  teeth,  336 

intestinal  worms,  336 

imperforate  anus,  336 

rickets,  337 

jaundice,  337 

cirronosis,  337 

accidental  morbid  tissues,  337 
Foot,  bones  of  the,  338 
tarsus,  339 
astragalus,  339 
os  calcis,  339 
os  cuboides,  340 
os  scaphoides,  340 
ossa  cuneiformia,  340 
structure  of  the  tarsal  bones,  341 
development,  341 
metatarsus,  341 

structure  and  development  of  its  bones,  342 
toes  :  their  phalanges,  &c.  342 
joints  of  the  tarsus,  342 

anterior  astragalo-calcanien  articulation,  342 

cuneo-scaphoid  articulation,  343 

cuboido-cuneen  articulation,  343 

articulation  of  the  two  rows  of  tarsal  bones  to  each 
other,  343 

astragalo-scaphoid  articulation,  343 

calcaneo -cuboid  articulation,  343 
motions  o<  the  tarsal  joints,  3-44 
tarso-metatarsal  articulations,  344 
metatarsal  articulations,  345 
metatarso-phalangeal  articulations,  345 
articulations  of  the  toes,  345 
motions  of  the  metatarsal  joints,  345 

metatarso-phalangeal  joints,  345 
phalangeal  joints,  345 
general  mechanism  and  endowments  of  the  foot, 
arches,  &c.  346 
Foot,  abnormal  conditions  of  the,  347 
dislocations,  347 

congenital  displacements  of  the  bones,  347 
distortions,  348 
varus,  348 
valgus,  348 
pes  equinus,  349 
flat-foot,  350 
Foot,  regions  of  the,  351 
dorsum,  351 

integuments  and  subcutaneous  cellular  tissue, 

veins,  &c.  351 
fascia  and  aponeurosis,  352 
region  of  the  toes,  353 
plantar  region,  353 

proper  plantar  legion,  353 
fascia  plantaris,  354 
deep-seated  parts,  354 
plantar  region  of  the  toes,  355 
practical  inferences,  355 
Foot,  muscles  of  the,  357 
of  the  dorsum : 

extensor  brevis  digitorum,  357 
interossei  extend  s.  dorsales,  358 
of  the  plantar  region  : 
abductor  pollicis,  353 
flexor  brevis  pollicis,  358 
adductor  pollicis,  358 
abductor  minimi  digiti,  358 
flexor  brevis  minimi  digiti,  358 
flexor  brevis  digitorum  s.  perforatus,  358 
flexor  digitorum  accessorius  s.  massacarnea  Jacobi 

Sylvii,  358 
lumbiicales,  358 

interossei  interni  s.  plantares,  358 
transversalis  pedis,  358 
classification  of  the  muscles  of  the  foot  according  to 
their  effects,  359 
Fore-arm,  (surgical  anatomy,)  361 

integuments,  and  parts  immediately  subjacent,  361 
aponeurosis,  362 
vessels,  363 

fracture  of  the  fore-arm,  364 
Fore-arm,  muscles  of  the,  365 
in  the  anterior  region,  366 

supinator  radii  longus,  366 

extensor  carpi  radialis  longior,  366 

pronator  radii  teres,  366 

flexor  carpi  radialis,  366 

palmaris  longus,  367 

flexor  communis  digitorum  sublhuis  s.  perfora- 
tus, 367 


Fore^arm,  (continued), 

flexor  carpi  ulnaris,  367 

flexor  longus  proprius  pollicis,  368 

flexor  communis  digitorum  profundus  s.  peifo- 

rans,  368 
pronator  quadratus,  368 
in  the  posterior  legion,  368 
anconeus,  368 
extensor  carpi  ulnaris,  369 
extensor  communis  digitorum,  369 
extensor  carpi  radialis  brevior,  369 
supinator  radii  brevis,  369 
extensor  ossis  metacarpi  pollicis,  369 
extensor  primi  internodii  pollicis,  S70 
extensor  secundi  internodii  nollicis,  370 
indicator  s.  extensor  proprius  primi  digiti 
manus,  370 
Fourth  pair  of  nerves,  370 
Ganglion,  37 1 

organization,  372 

reddish  grey  matter,  372 
fibres,  374 

arrangement  ot_the  fibres  in  ganglia,  374 
nature  of  the  fibres  connected  with  ganglia,  375 
coverings,  376 
bloodvessels,  376 
chemical  composition,  376 
Gasteropoda,  377 

characters  of  the  class,  377 
division  into  orders,  377 
tegumental^  system,  379 
growth  of  shell,  380 
operculum,  384 
organs  of  digestion,  384 
mouth,  384 
alimentary  canal,  384 
accessory  glands,  388 
salivary  glands,  38a 
biliary  system,  388 
organs  of  respiration,  3ho 
organs  of  circulation,  390 
nervous  system,  392 

common  sensation,  394 
touch,  taste,  smell,  394 
vision,  395 
generative  system,  396 

ova,  401 
reproduction  of  lost  parts,  402 
muscular  integument,  402 
body, 402 

retractile  muscles,  403 
foot,  403 

particular  secretions,  404 
Gelatin,  404 

Generation,  (in  human  and  comparative  anatomy,)  organs 
and  means  of,  406 
fissiparous  generation,  407 
gemmiparous  generation,  407 
oviparous  generation,  407 

I.  Division.— Animals  in  which  ovigerous  organs 
only  have  been  distinctly  recognized,  409 

II.  Division. — Animals  provided  with  ovigerous 
organs  combined  with  an  additional  secreting 
structure,  probably  subservient  to  the  fertili- 
zation of  the  ova,  410 

III.  Division. — Ovigerous  and  impregnating  or- 
gans co-existent,  but  the  cooperation  of  two 
individuals  necessary  for  mutual  impregna- 
tion, 411 

IV.  Division. — Sexes  distinct,  i.  e.  ovigerous  and 
impregnating  organs  placed  in  separate  indi- 
viduals, 412 

Insects,  413 
Arachnida,  417 
Crustacea,  417 
Mollusca,  417 
Vertebrate  ovipara,  418 
Fishes,  418 
Reptiles,  419 
Birds,  421 
Mammalia,  42i 
testes,  422 
prostate,  422 
Cowper's  glands,  422 
accessory  vesicles,  423 
penis,  structure  of,  423 
Generation,  (in  physiology,)  424 

I.  Function  of  reproduction  generally  considered,  426 
introductory  remarks,  426 
theories  of  generation,  427 
spontaneous  generation  of  animals,  429 
II.  Sketch  of  the  principal  forms  of  the  reproductive 
function  in  different  animals,  432 

1.  Non-sexual  reproduction,  432 

fissiparous  generation,  432 
gemmiparous  generation,  433 
reproduction  by  separated  buds  or  sporules, 
433 

2.  Sexual  reproduction,  434 

nature  of  the  ovum,  434 
hermaphrodite  generation,  434 


ANALYTICAL  INDEX. 


1011 


Generation,  (continued) . 

dioecious  reproduction,  or  with  distinct  in- 
dividuals of  different  sexes.  Oviparous 
and  viviparous  generation,  435 

ovoviparous  generation,  435 

varieties  in  respect  to  utero-gestalion  and 
the  development  of  the  young,  43b' 

Marsupiate  generation,  436 

Monotrematous  generation,  437 

comparison  of  animal  and  vegetable  repro- 
duction, 437 

synoptical  table  of  the  various  forms  of  the 
reproductive  process,  438 

III.  Reproductive  function  in  man  and  the  higher 

animals : 

I.  sketch  of  this  function  in  man,  438 
organs  of  reproduction,  438 
puberty,  439 

structural  differences  of  the  sexes,  439 

menstruation,  439 

periodical  heat  in  animals,  441 

age  at  which  pubcriy  occurs,  44  l 

period  during  which  the  generative  function 

is  exercised,  442 
effects  of  castration,  443 
sexual  feeling,  443 

relation  of  reproduction  to  the  bruin,  444 
distinction  of  species.    Mules,  444 
functions  of  the  external  organs  of  repro- 
duction, 445 
erection,  445 

IV.  Changes  consequent  on  fruitful  sexual  union  : 

1.  As  regards  the  female.    Conception,  447 

approximation  of  the  fimbriated  extrt  mities 

or  the  Fallopian  tubes  to  the  ovary,  447 
changes  in  the  ovaries:    bursting  of  the 

Graafian  vesicles,  443 
formation  of  the  corpus  luteum,  449 
descent  of  the  ovum.    Its  structure  and 

changes  during  its  passage,  451 
time  at  which  it  arrives  in  the  uterus,  453 
changes  in  the  uterus  after  conception,  454 
irregularities  in  the  descent  of  the  ovum, 

455 

circumstances  influencing  liability  to  con- 
ception, 456 
signs  of  recent  conception  in  women,  4  57 

2.  As  regards  the  male,  4b7 

properties  of  the  seminal  fluid,  457 
chemical  properties,  458 
spermatic  animalcules,  459 
table  of  their  sizes  in  different  animals, 
460 

circumstances  upon  which  the  fecundating 
property  of  the  seminal  fluid  depends,  46) 

difference  between  the  fecundated  and  uufe- 
cundated  ovum,  462 

is  material  contact  of  the  semen  and  ovum 
necessary  ?  462 

external  and  artificial  fecundation,  462 

courseof  the  seminal  fluid  within  the  female 
organs,  464 

nature  of  the  fecundating  print  iple.  Hypo- 
thesis of  an  aura,  &c.  466 

general  conclusions  respecting  fecundation, 
467 

V.  Miscellaneous  topics  relating  to  the  preceding 
history  of  generation,  468 

1.  superlactation,  469 

2.  influence  exerted  by  parents  on  the  qualities  of 

their  offspring,  470 

3.  number  of  children  and  relative  proportion  of 

the  male  and  female  sexes,  478 
table  of  the  proportion  of  males  to  females 
born  in  different  countries,  47S 

Gland,  480 

divisions  and  kinds  of  glands,  431 
situations,  481 
organization,  481 

minute  structure,  481 
excretory  ducts,  486 

structure  of  the  secreting  canals  and  excretory 

ducts,  487 
bloodvessels,  487 

arrangement  of  their  minute  subdivisions,  488 
lymphatics,  489 
nerves,  489 

interstitial  cellular  tissue,  489 
investing  membrane,  489 

general  conclusions  regarding  the  minute  struc- 
ture of  glands,  490 

hypotheses  on  this  subject,  490 
development  of  glands,  492 
Glosso-pharyngeal  nerve,  492 

origin  and  course,  ganglion  jugulare,  ramus  tympa- 

nicus  or  nerve  of  Jacobson,  &c.  492 
digastric  and  stylo-hyoid  branch,  496 
carotid  branches,  496 
pharyngeal  branches,  496 
lingual  blanches,  497 
tonsillitic  branches,  497 
physiology  of  this  nerve,  497 


G lit tceal  Region,  (in  surgical  anatomy,)  500 
Groin,  Region  of  the,  (in  surgical  anatomy,)  503 
Hcematosine,  503 

Hair.    Vide  Tegumentary  System,  505 
Hand,  Bones  oj  the,  (human  anatomy,)  505 

I.  Carpus,  505 

os  naviculare,  505 
os  lunare,  505 
os  cuneiforme,  505 
os  pisiforme,  505 
os  trapezium,  506 
os  trapezoides,  506 
os  magnum,  506 
os  unciforme,  506 

structure  and  development  of  the  bones  of  carpus, 

506 

II.  Metacarpus : 

first,  second,  third,  fourth,  and  fifth  metacarpal 
bones,  507 

structure  and  development  of  the  metacarpus, 

507 

III.  Fingers,  507 

metacarpal,  middle,  and  ungual  phalange?,  507 
structure  and  development,  507 
joints  of  the  hand  : 

joints  of  the  carpus,  508 

articulaiion  of  the  two  rows  of  carpal  bones  to 
each  other,  508 

motions  of  the  carpal  articulations,  503 

articulation  of  the  pisiform  bone,  508 
carpo-me  tacarpal  joints,  509 

motions  of  the  carpo-metacarpal  joints,  509 
joints  of  the  fingers  : 

metacarpophalangeal  joints,  510 

phalangeal  joints,  M0 

motions  o(  the  joints  of  the  finders,  510 
Hand,  Abnormal  Conditions  oj  the,  510 

I.  As  results  of  accidents,  510 

luxations  and  fractures,  510 

luxation  of  the  bones  of  the  carpus,  510 

luxation  of  the  bones  of  the  meiacaipus,  511 

luxation  of  the  metacarpal  bone  of  the  thumb, 
511 

luxation  of  the  phalanges  of  t lie  fingers,  511 

first  phalanx  of  the  thumb  from 
the  metacarpal  bone,  511 
anatomical  characters  of  this  accident,  512 
luxation  ot  the  second  and  third  phalanges,  514 

II.  Diseased  conditions  ; 
spina  ventosa,  case  of,  514 
strumous  osteitis,  516 
malignant  tumours,  516 

abnormal  conditions  of  the  fingers,  the  result  of 
accidents,  and  morbid  affections  of  one  or 
more  of  theirconstituent  structures,  517 

contraction  of  ihe  fingers  from  disease  of 

the  palmar  fascia,  517 
anchylosis  of  the  joints  of  the  phalanges, 

518 

III.  Congenital  malformations  of  the  hand,  519 
Hand,  Muscles  of  the,  (human  anatomy,)  519 

I.  Muscles  of  the  palm  : 

a.  muscles  of  the  external  palmar  region,  519 
abductor  pollicis,  519 

relations,  5  19 
flexor  ossis  metacarpi  s.  opponens  pollicis,  519 

relations,  590 
flexor  brevis  pollicis,  520 

relations,  520 
adductor  pollicis,  520 

relations,  520 

b.  muscles  of  the  internal  palmar  region,  520 
palmaris  brevis,  520 

relations,  520 
abductor  minimi  digiti,  520 

relations,  use,  520 
flexor  brevis  minimi  digiti,  521 

relations,  521 
adductor  ossis  metacarpi  s.  opponens  minims 
digiti,  521 

relations,  521 

c.  muscles  of  the  middle  palmar  region,  521 

Iumbricales,  521 

relations  and  uses,  521 
intcrossei  interni  ditiitorum,  521 

relations,  use,  521 

II.  Muscles  of  the  dorsum  : 

interossei  externi,  521 
relations,  uses,  522 
motions  of  the  hand  and  its  parts,  522 
Hand,  Regions  of  the,  (surgical  anatomy),  523 
I.  Palmar  region,  523 
skin,  524 

subcutaneous  cellular  tissue  and  nerves,  524 
aponeurosis,  524 

anterior  annular  ligament,  524 
palm, u*  fascia,  525 
vessels  and  nerves  : 

ulnar  artery,  525 

radial  artery,  526 

veins,  lymphatics,  nerves,  526 
median  nerve,  527 


1012 


ANALYTICAL  INDEX. 


Hand,  Regions  of  the,  (continued). 

ulnar  nerve,  527 
muscles  and  tendons,  527 
II.  Dorsal  region,  527 
skin,  528 

subcutaneous  layer  and  veins,  508 
aponeurosis,  5'28 
nerves,  528 

tendons  and  muscles,  528 
arteries,  529 

remarks  on  amputations  of  dilFerent  members  of 
tlie  hand,  529 
Hearing,  Organ  of.    The  ear,  529 

1.  The  ear-bulb  or  fundamental  organ  of  hearing,  529 

1.  osseous  labyrinth,  5_>9 

vestibule,  530 
semicircular  canals,  530 
cochlea,  53 l 

canalis  spiralis,  531 

axis,  modiolus,  columella  or  central  pil- 
lar, 53  I 

lamina  spiralis,  spiral  lamina,  and  scala;, 

532 

the  aqueducts,  532 

membrane  lining  the  labyrinthic  cavity, 

533 

of  the  cochlea  in  the  recent  stale,  533 
farther  observations  on  the  aqueducts,  536 
of  the  liquid  of  the  labyrinthic  cavity,  pe- 
rilymph, or  liquid  of  Cotugno,  53S 

2.  membranous  labyrinth,  536 

common  sinus,  membranous  ampullae,  and 

membranous  semicircular  tubes,  537 
saccule,  sacctilus  rotundus,  538 
liquid  of  the  membranous  labyrinth,  endo- 

lymph  or  vitreous  humour  of  the  ear,  538 
of  the  masses  of  calcareous  matter  contained 

within  the  membranous  labyrinth,  otolithi 

and  otoconia,  539 
auditory  or  acoustic  nerve  and  its  divisions, 

539 

bloodvessels  of  the  labyrinth,  512 

arterir  cochlea?  and  arteria  vestibuli,  542 
I!.  Accessory  parts  of  the  apparatus  of  hearing,  543 
I.  Middle  ear  or  tympanum  and  its  appendages: 
cavity  of  the  tympanum,  543 

promontory,  fenestra  rotunda,  and  fenes- 
tra ovalis,  543 
eminentia  papillaris  s.  protuberantia  py- 

ramidalis,  544 
cochleariform  process,  544 
osseous  portion  of  tlie  auditory  passage,  544 

tympanic  ring,  544 
membrane  of  the  tympanum,  545 

structure  of  the  proper  membrane,  545 
hiatus  Rivinianus,  546 
the  ossicles  or  small  bones  of  the  ear,  546 
malleus  or  hammer  bone,  546 
incus  or  anvil-bone,  546 
stapes  or  stirrup-bone,  547 
position,  connexions,  and  articulations  of 

the  small  bones  of  the  ear,  547 
muscles  of  the  small  bones,  548 

internus  mallei  s.  tensor  tympani,  548 
stapedius,  muscle  of  the  stapes,  549 
lining  membrane  of  the  cavity  of  the  tym- 
panum, 549 
the  Eustachian  tube,  549 
osseous  part,  549 

cartilaginous  and  membranous  por- 
tion, 550 

2.  The  external  ear,  including  the  auditory  pas- 
sage, 5  SO 

A.  The  auricle,  auricula  s.  pinna,  550 

helix,  550 
antihelix,  551 
antitragus,  551 
tragus,  551 
ligaments  of  the  ear: 

anterior  ligament  and  posterior  ligament, 
651 

muscles  of  the  ear : 

muscles  which  move  the  ear  as  a  whole,  or 
extrinsic  muscles : 

elevator  auris,  attollens  auriculam, 

551 

retractor  muscles,  retrahentes  auri- 

culam,  552 
anterior  muscle,  attrahens  auricu- 
Iam,  552 
intrinsic  muscles  of  the  ear: 
helicis  major,  552 
helicis  minor,  552 
tragicus,  552 
antitragicus,  552 
transversus  auriculae,  552 

B.  The  external  auditory  passage,  meatus  audito- 

rius  externus,  552 

the  cartilaginous  and  membranous  por- 
tion, 552 

incisurae  Santorinianaj,  553 
ceruminous  glands,  553 


Hearing,  Organ  of,  (continued) . 

nerves  of  the  accessory  parts  of  the  apparatus 

of  hearing,  554 
nerves  of  the  tympanum,  554 

nervus  petrosus  superficialis,  554 
intumescentia  gangliformis  nervi  fa- 
cialis, 554 
chorda  tympani,  554 
ramus  auricularis  nervi  vagi,  554 
nervous  anastomosis  in    the  tym- 
panum, 554 
nervus  lympanicus,  554 
nerves  of  the  auricle  and  auditory  pas- 
sage, 555 

arteries  of  the  external  ear  and  tympanum, 

556 

III.  1.  development  and  abnormal  conditions  of  the 

organ  of  hearing,  5S7 

A.  of  the  ear-bulb,  557 

B.  of  the  tympanum  and  its  contents  : — 

cavity  of  the  tympanum,  559 
small  bones  of  the  tympanum,  560 

C.  of  the  external  ear,  561 

IV.  parallel  between  the  ear  and  the  eye,  562 
Hearing,  (in  physiology,)  564 

preliminary  observations  on  sound,  565 

pitch,  intensity,  and  quality  in  musical  sounds,  566 

reflexion  of  sound,  565 

part  performed  by  each  portion  of  the  auditory  appa- 
ratus in  the  function  of  hearing  :  — 

I.  the  internal  ear,  567 

vestibule,  the  essential  part,  567 
office  of  the  otolithes,  567 
function  of  the  cochlea,  568 

function  of  the  semicircular  canals  and  sinus 
commune,  669 

II.  The  accessory  parts  of  the  organ,  571 

the  auricle,  571 

the  tympanum  and  its  contents,  572 
Eustachian  tube,  576 
functions  of  the  nerves,  576 
Heart,  (in  anatomy,)  577 
Human  heart  (normal  anatomy) : 
position,  578 

form  and  external  surface,  578 
right  auricle,  579 

external  surface,  579 
internal  surface,  579 

tuberculum  Loweri,  580 

fossa  ovalis,  vestigium  foraniinis  ovalis,  5S0 

annulus  s.  isthmus  Vieussenii,  5S0 

remains  of  the  Eustachian  valve,  580 

valvula  Thebesii,  580 

foramina  Thebesii,  580 

musculi  pectinati,  580 

auriculo-ventiicular  opening,  580 
right  ventricle,  580 

external  surface,  5S0 
internal  surface,  580 

colttmnae  carnese,  580 

musculi  papillares,  581 

valvula  tricuspis  s.  triglochis,  581 

chordae  tendinea;,  581 

semilunar  valves,  581 

corpus  Arantii,  513 
left  auricle  : 

external  surface,  582 
internal  surface,  582 
left  ventricle : 

external  surface,  582 
internal  surface,  582 

bicuspid  or  mitral  valve,  583 

semilunar  valves,  584 

sinuses  of  Valsalva,  584 
septum  of  the  ventricles,  584 

thickness  of  the  walls  of  the  several  cavities  of  the 
heart,  585 

measurements,  586 
relative  capacities  of  the  several  cavities,  585 

measurements,  586 
relative  dimensions  of  the  auriculo-ventricular  ori- 
fices, 587 

circumference  of  the  aortic  and  pulmonary  orifices, 

587 

measurements,  587 
size  and  weight  of  the  heart,  587 
structure  of  the  heart,  587 
tendinous  texture,  587 

auriculo-ventricular  tendinous  rings,  587 
arterial  tendinous  rings,  5n7 
tendinous  structure  of  the  auriculo-ventri- 
cular valves,  589 
tendinous  structure  in  the  arterial  valves, 
589 

attachment  of  the  middle  coat  of  the  arteries 
to  the  arterial  tendinous  rings,  539 
muscular  tissue,  590 

of  the  ventricles,  590 

of  the  auricles,  593 
inner  membrane  of  the  heart,  594 
nerves  of  the  heart,  595 

middle  cardiac  nerve,  595 


ANALYTICAL  INDEX. 


1013 


Human  Heart,  (continued.) 

inferior  cardiac  nerve,  595 

lelt  cardiac  nerve,  595 

cardiac  plexus,  596 
bloodvessels  of  the  heart,  596 

great  coronary  vein,  596 

smaller  posterior  coronary  vein,  597 
anterior  coronary  veins,  597 

venae  minimse,  or  veins  of  Thebesius,  597 

sinus  of  the  coronary  vein,  597 
sympathies  of  the  heart,  5&7 
pericardium,  597 

uses  of  the  pericardium,  59? 
relative  position  of  the  vessels  within  the  peri- 
cardium, 598 
peculiarities  of  the  foetal  heart,  599 

value  of  the  foramen  ovale,  599 

Eustachian  valve,  599 
Physiology  of  the  heart: 

mode'of  action  ol  the  valves,  600 
movements  of  the  heart,  602 

systole  and  diastole  of  the  auricles,  602 
ventricles,  603 

impulse  of  the  heart,  604 
most  irritable  parts  of  the  heart,  607 
duration  of  contractile  power  after  death,  608 
frequency  of  the  heart's  action,  609 

number  of  pulsations  in  different  animals,  609 
cause  of  motion  of  the  heart,  610 
upon  what  does  the  peculiar  irritability  of  the 

heart  depend  t  612 
constancy  of  the  heart's  action,  613 
regularity  of  the  heart's  movements,  6*13 
sounds  of  the  heart,  614 

first  sound,  6 16 

second  sound,  617 
Heart  (arrangement  of  the  fibres  of  the),  619 
Heart  (abnormal  conditions  of  the),  630 

I.  congenital  abnormal  conditions  : 

congenital  aberrations  of  position,  ectopia  cordis, 
630 

malformations  by  defect  of  development,  631 
malformations  of  the  valves,  633 
congenital  absence  of  the  pericardium,  633 
malformations  by  excess  of  development,  (i34 
anomalous  connexions  of  the  vessels  of  the  heart, 
635 

displacement  or  ectopia  of  the  heart  as  a  conse- 
quence of  disease,  635 

II.  morbid  alterations  of  the  muscular  substance  of 
the  heart : 

inflammation,  carditis  proper,  635 
suppuration,  636 
ulceration,  637 
induration,  637 

cartilaginous  and  osseous  transformations,  637 
tubercles,  637 
scirrhus,  637 

medullary  fungus,  encephaloid  tumours,  637 

melanosis,  633 

hypertrophy  : 

simple,"  i.e.  without  change  in  the  capa- 
city of  the  cavities,  638 
with  dilatation  or  increased  capacity  of 
the  cavities,   excentric  hypertrophy, 
active  aneurism  of  the  heart,  639 

dilatation  of  the  cavities  of  the  heart,  pas- 
sive aneurism,  640 

dilatation  of  the  oiifices  of  the  heart,  640 

aneurism  of  the  heart,  640 

atrophy  of  the  heart,  642 

morbid  deposit  of  fat  on  the  heart,  fatty  de- 
generation, 642 

rupture  of  the  heart,  643 
morbid  states  of  the  membranes  of  the  heart  : — 

morbid  states  of  the  pericardium,  643 

white  spot  on  the  heart,  644 

tubercular  formations,  645 

cysts,  645 

hydrops  pericardii  or  hydropericardium,  645 

pneumopericardium,  645 

morbid  states  of  the  endocardium,  645 

chronic  valvular  diseases,  646 

dilatation  of  the  valves,  647 

nlrophyof  the  valves,  647 

entozoa  in  the  heart,  64" 

states  of  the  blood  in  the  heart  after  death, 
648 

Heat,  animal,  648 

temperature  of  the  human  body,  649 
of  the  mammalia,  649 
of  birds,  64Q 
of  reptiles,  649 
of  fishes,  649 
of  insects,  650 
of  Crustacea,  650 
of  mollusca,  650 
general  conditions  of  organization  in  relation  with 
the  production  of  a  greater  or  less  degree  of 
heat,  750 

temperature  of  different  parts  of  the  body,  654 


Heat,  animal,  (continued.) 

relations  between  the  temperature  of  internal 
parts,  654 

relations  between  the  temperature  of  external 
parts,  655 

difference  of  temperature  according  to  depth,  656 
influence  of  external  temperature  generally,  658 
variations  in  temperature  independently  of  external 

temperature,  658 
influence  of  the  natural  temperature  of  the  air  on 

that  of  the  body,  65K 
influence  of  different  media  upon  temperature,  659 
effects  of  external  temperature  upon  an  isolated  part 

of  the  body,  660 
effects  of  partial  heating,  660 
effects  of  excessively  high  or  excessively  low  ex 

ternal  temperature  upon  the  temperature  of 

the  body,  660 
influence  of  evaporation,  661 
relations  of  the  bulk  of  the  body  to  animal  heat,  662 
relations  of  age  to  animal  heat,  662 
differences  of  constitution  in  relation  to  the  pro- 
duction of  heat  among  animals,  667 
influence  of  the  seasons  on  the  production  of  animal 

heat,  668 

differences  according  to  the  nature  of  the  climate, 

670 

influence  of  sleep  on  the  production  of  heat,  670 

phenomena  presented  by   hybernating  animals 
with  regard  to  the  production  of  heat,  671 

of  the  system  upon  which  the  external  temperature 
acts  primarily  and  principally,  673 

influence  of  temperature  on  the  vitality  of  cold- 
blooded animals,  673 

influence  of  temperature  on  the  vitality  of  warm- 
blooded animals  and  of  man  in  the  states  of 
health  and  disease,  674 

effects  of  various  other  causes  of  modification  in  ex- 
ternal agents,  680 

confirmation  of  the  general  results,  682 

of  the  physical  cause  of  animal  heat,  683 
Hermaphroditism,  or  Hermaphrodism,  684 

classification  of  hermaphroditic  malformations,  685 

I.  spurious  hermaphroditism; — ■ 

A.  in  the  female,  6s5 

1.  abnormal  development  or   magnitude  of 

the  clitoris,  6h6 

2.  from  prolapsus  of  the  uterus,  690 

B.  in  the  male,  690 

1.  extroversion  of  the  urinary  bladder,  691 

2.  adhesion  of  the  inferior  surface  of  the 

penis  to  the  scrotum,  691 

3.  fissure  of  the  inferior  part  of  the  urethra, 

perinaeum,  &c.  691 

II.  true  hermaphroditism,  695 

A.  lateral  hermaphroditism,  696 

1.  an  ovary  on  the  right  side  and  a  testis  on 

the  left,  693 

2.  a  testicle  on  the  left  and  an  ovary  on  the 

right  side,  700 

B.  transverse  hermaphroditism,  701 

3.  transverse  hermaphroditism  with  external 

sexual  organs  of  the  female  type,  "01 
2.  transverse  hermaphroditism  with  the  ex- 
ternal sexual  organs  of  the  male  type,  704 

C.  double  or  vertical  hermaphroditism,  706 

1.  male  vesicula:  serninalcs,  &c.  superadded  to 

organs  of  the  female  sexual  type,  707 

2.  imperfect  female  uterus,  &c.  superadded  to 

asexual  organization  essentially  male  in 
its  type,  707 

3.  Coexistence  of  female  ovaries  and  male 

testicles,  71 1 
two  testicles  and  one  ovary,  712 
two  testicles  and  two  ovaries,  712 

III.  hcrmaphrodolism  as  manifested  in  the  general 

conformation  of  the  body  and   in  the  se- 
condary sex'ial  characters,  714 
general  summary  with  regard  to  the  nature  of 
hermaphroditic  malformations,  722' 
1.  of  the  varieties  of  spurious  hermaphro- 
ditism, 722 
nature  of  true  hermaphroditic  malform- 
ations, 723 

anatomical  degree  of  sexual  duplicity  in  her- 
maphroditism, 728 

1.  fallacies  in  judging  of  the  addition  of  male 

seminal  ducts  to  a  female  type  of  sexuiil 
organs,  729 

2.  fallacies  in  the  supposed  co-existence  of  a 

female  uterus  with  testicles  and  other 
organs  of  a  male  sexual  type,  730 

3.  fallacies   in   a   supposed   co-existence  of 

testicles  and  ovaries,  731 
physiological  degree  of  sexual  perfection  in  her- 
maphrodites, 732 
causes  of  hermaphroditic  malformations,  733 
hermaphroditism  in  double  monsters,  736 
Hernia,  (morbid  anatomy,)  738 

circumstances  under  which  protrusions  of  the  ab- 
dominal viscera  take  place,  varieties,  &c.  738 


1014 


ANALYTICAL  INDEX. 


Hernia,  (continued.) 

inguinal  hernia,  750 

by  direct  descent,  755 
crural  or  femoral  hernia,  756 
umbilical  hernia,  761 
Hibernation,  764 

order  of  consideration  of  the  effects  of  hibernation, 
766 

I.  of  sleep,  766 

IT.  of  the  sleep  of  hibernating  animals,  766 

III.  of  perfect  hibernation,  768 

state  of  the  several  functions  in  hibernation  : — 
sanguification,  768 
respiration,  769 

comparative  temperature  of  hibernating 
animals  with  that  of  the  atmosphere, 770 
circulation,  771 
defecation,  772 
nervous  system,  772 

irritability,  772 

motility  of  muscular  fibre,  773 

IV.  of  reviviscence,  774 

V.  of  torpor  from  cold,  775 

Hip-joint,  anatomy  of  the,  (human  anatomy,)  776 
the  bones,  776 

acetabulum,  776 
head  of  the  femur,  777 
cartilage  of  the  acetabulum,  777 
fibro-cartilage  of  ditto,  777 
ligaments,  777 

round  ligament,  778 
capsular  ligament,  778 
synovial  membrane,  779 
arteries,  779 
nerves,  779 
motions,  779 
Hip-joint,  abnormal  conditions  of  the,  780 

Sect.  1.  congenital  malformations  of  the  hip-joint: 
original  luxation,  790 

anatomical  characters  of  the  affection,  782 

history  of  a  case  of  congenital  malformation  of 
the  left  hip-joint,  with  the  anatomical  ex- 
amination of  the  articulation,  784 

history  of  a  second  case,  786 
Sect.  II.  disease: 

inflammation  of  the  synovial  membrane  and 
other  structures,  787 
synovitis  coxa?,  with  periostitis,  788 

cartilages,  inflammation  and  destruction  of  the, 
788 

bones,  strumous  osteitis,  morbus  coxae,  scrofulous 
affection  of  the  hip-joint,  789 

acute  arthritis  coxae,  790 

'  anatomical  characters,  792, 

chronic  strumous  arthritis  coxa?,  70S 
anatomical  characters,  794 

chronic  rheumatic  arthritis  coxae,  chronic  rheu- 
matism, 798 

anatomical  characters,  801 
Sect.  III.  accidents : 

I.  fractures : 

fracture  of  the  fundus  of  the  acetabulum,  802 
fracture  of  the  brim  of  the  acetabulum,  803 
fracture  of  the  superior  extremity  of  the  femur, 
804 

A.  intra-capsular  fracture  of  the  neck  of  the 

femur,  804 

B.  extra-capsular  fracture  of  the  neck  and 
fracture  of  the  superior  portion  of  the 
shaft  of  the  femur,  805 

C.  fracture  of  the  neck  of  the  femur  com- 
plicated with  fracture  through  the  tro- 
chanter major,  805 

I).  fracture  of  the  neck  of  the  thigh-bone, 
with  impaction  of  the  superior  or  cotyloid 
fragment  into  the  cancellated  tissue  of 
the  upper  extremity  of  the  shaft  of  the 

femur,  8Qf» 
anatomical  characters  of  fracture  of  the 

neck  of  the  thigh-bone,  807 
does  bony  consolidation  of  the  intra- 
capsular fracture  of  the  cervix  femoris 
ever  occur  i  810 

II.  luxations: 

dislocation  of  the  head  of  the  femur  upwards  and 

backwards  on  the  dorsum  of  the  ilium,  815 
anatomical  characters  of  this  dislocation,  816 
dislocation  backwards  or  towards  the  ischiatic 
notch,  818 

anatomical  characters  of  this  dislocation,  820 
dislocation  upwards  and  inwards  on  the  pubes,  820 
anatomical  characters  of  this  luxation,  821 
dislocation  downwards  and   inwards   into  the 
foramen  ovale,  822 
anatomical  characters,  823 
cases  of  unusual  dislocations,  824 
upwards  and  outwards,  824 
downwards  and  backwards,  824 
Hyperemia  and  /Incemia,  (in  morbid  anatomy,)  825 
Hypertrophy  and  Atrophy,  (in  morbid  anatomy,)  826 


Iliac  Arteries,  827 

primitive  iliac  arteries,  common  iliacs,  827 
internal  iliac  artery,  828 
branches : 

1.  internal  branches : 

ilio-lumbar  artery,  829 
lateral  sacral  artery,  830 
middle  hsemorrhoidal  artery,  830 
vesical  arteries,  830 
umbilical  artery,  830 
uterine  artery,  831 
vaginal  artery,,  831 

2.  external  branches : 

obturator  or  thyroid  artery,  831 
glutaeal  artery,  833 
ischiatic  artery,  833 
internal  pudic  artery,  834 
branches : 
external  haemorrhoidal  arteries,  835 
perineal  artery,  835 
artery  of  the  corpus  cavernosum,  836 
artery  of  the  dorsum  penis,  836 
external  iliac  artery,  837 

relations,  coverings,  connexions,  837 
branches : 

anterior  or  circumflex  iliac  artery,  842 
epigastric  artery,  842 
methods  of  operation  for  the  ligature  of  the  external 
iliac  arteries,  844 
comparative  merits  of  the  different  methods,  846 
operations  for  the  ligature  of  the  internal  iliac,  849 
ligature  of  the  primitive  iliac,  849 
Jnnuminata  Arteria,  {human  unatomy,)  850 
relations,  Sec.  850 
anomalies,  852 
ligature,  852 
Instcta,  853 

Table  of  the  arrangement  of  insects  according  to  the 
system  of  Mr.  Stephens,  856 

Order  I.  Coleoptera,  859 

Order  II.  Dermaptera,  863 

Order  III.  Orthoplera,  864 

Order  IV.  Neuroptera,  864 

Older  V.  Trichoptera,  865 

Order  VI.  Hymenoptera,  865 

Order  VII,  Strepsptera,  866 
Sub-class,  Haustellata: 

Order  VIII.  Lepidoptera,  866 

Order  IX.  Diptera,  867 

Order  X.  Homaloptera,  867 

Order  XI.  Aphaniptera,  867 

Order  XI  I.  Aptera,  868 

Order  XIII.  Hemiptera,  868 

Order  XIV.  Homoptera,  868 
Different  states  of  existence  : 

the  eeg,  869 

the  larva,  869 

external  anatomy  of  the  larva,  870 
of  the  head,  872 
organs  of  locomotion,  873 
grow ih  and  changes  of  the  larva,  874 

the  pupa,  nymph,  aurelia  or  chrysalis,  879 

the  imago  or  perfect  state,  880 
Dermo-skeleton,  8b  I 

its  chemical  composition:  chitine,  881 

its  thirteen  segments,  882 

articulations,  883 

table  of  the  parts  and  appendages  of  the  head,  885 
account  of  these,  885 
mandibles,  888 
maxilla?,  889 
antennae,  890 

internal  parts  of  the  head,  892 
mouth,  897 

development  of  the  head,  9O9 
thorax,  911 

table  of  parts,  9 13 

pro-thorax,  914 

mesu-thorax,  914 

meta-thorax,  915 
abdomen,  918 
Organs  of  locomotion.— The  wings,  924 
articulations  of  the  wings,  926 
lieuration,  926 
Hie,  928 
the  legs,  931 

aberrations  of  form  in  the  organs  of  locomotion, 

933 

muscular  system,  934 

muscles  of  the  larva,  935 

perfect  insect,  939 

nervous  system  : 

in  the  larva,  943 

nerves  of  the  head,  594 

of  the  perfect  insect,  948 
organs  of  vision,  960 
organ  of  hearing,  96I 
organ  of  touch,  961 
ori>an  of  smell,  962 

development  of  the  brain  and  nervous  system,  962 


ANALYTICAL  INDEX. 


1015 


Insecta,  (continued.) 

organs  ot  nutrition  : 

alimentary  canal  and  its  appendages,  963 
peritoneal  coat,  963 
muscular  coat,  963 
mucous  coatf  966 
alimentary  canal  of  larva,  966 

appendages  of  the  canal,  973 
anal  or  proper  uriniferous  organs,  975 
adipose  tissue,  975 
circulatory  system,  976 

the  heart  or  great  dorsal  vessel,  976 
organs  of  respiration,  982 


Insecta  (x-ontinued*) 

function  of  respiration,  987 
organs  of  generation,  Q90 

tegumentary  appendages — hair,  scales,  and  spines,  993 
Insectivora,  9QA 
families,  994 
osteology,  995 
muscles,  998 
digestive  organs,  1000 

teeth,  1000 
nervous  system,  1002 
tegumemary  system,  1004 
organs  of  reproduction,  1005 


END  OF  VOL.  II. 


ERRATA  IN  VOLUME  II. 


Page  153,  col.  \,  line  13  from  bottom,  for  articulated,  read  reticulated. 

157,  col.  2,  line  20  from  bottom,  for  supra-spinata,  read  infra-spinata. 
174,  note,  dele  "  and  copied  into  Mr.  Mackenzie's  work  on  the  eye.'' 
344,  line  40,  for  inspection,  read  impaction. 

375,  col.  2,  note,  for  "  tarsor,"  read  "  tensor." 

376,  col.  2,  Bibliography,  insert  Berres. 

483,  col.  2,  line  25  from  bottom,  for  "  fluid,"  read  "  blind." 
587,  col.  1,  line  24  from  bottom,  for  45$,  read  31^. 
587,  col.  1,  line  22  from  bottom,  'for  41  J,  read  28|. 
587,  col.  1,  line  20  from  bottom,  'for  54|-f,  read  32§}. 
587,  col.  1,  line  18  from  bottom,  for  48|,  read  30^. 

598,  col.  2,  line  11  from  bottom,  for  "  The  nerves  can  be  traced,"  read  "The  nerves 

have  not  been  traced." 
608,  col.  2,  note,  for  "  Prinella,"  read  "  Prunelle." 
617,  col.  1,  line  32  from  bottom,  for  "  Enman,"  read  "  Erman." 
849,  col.  2,  line  5,  for  pecuniary,  reid  visceral. 
In  the  article  Heart,  , for  fig.  £72,  in  references,  read  fig.  274,  passim  and  vice  versa. 


MARCIIANT,  PRIMTEK,  I N  G RAM-CO U RT,  FENCHURCH-STREET. 


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